U.S. patent application number 12/083823 was filed with the patent office on 2009-03-12 for crimped yarn, method for manufacture thereof, and fiber structure.
Invention is credited to Kousuke Fukudome, Shozo Inoue, Hiroshi Kajiyama, Toshiaki Kimura, Kazuya Matsumura, Katsuhiko Mochizuki, Syusaku Narita, Atsushi Shinozaki.
Application Number | 20090068463 12/083823 |
Document ID | / |
Family ID | 37962490 |
Filed Date | 2009-03-12 |
United States Patent
Application |
20090068463 |
Kind Code |
A1 |
Mochizuki; Katsuhiko ; et
al. |
March 12, 2009 |
Crimped Yarn, Method for Manufacture thereof, and Fiber
Structure
Abstract
A crimped yarn includes a synthetic fiber which contains an
aliphatic polyester resin (A) and a thermoplastic polyamide resin
(B) and exposed area ratio of the aliphatic polyester resin (A)
with respect to fiber surface area is 5% or less and a crimp is
imparted to a multifilament comprising said synthetic fiber, and a
fiber structure containing said crimped yarn as at least a part
thereof. Furthermore, a crimped yarn in which the aliphatic
polyester resin (A) and the thermoplastic polyamide resin (B) are
constituted of a polymer alloy type synthetic fiber, or a crimped
yarn constituted by a sheath/core type composite fiber in which the
core component comprises the aliphatic polyester resin (A) or a
polymer alloy of the aliphatic polyester resin (A) and the
thermoplastic polyamide resin (B) and the sheath component
comprises the thermoplastic polyamide resin (B), and a fiber
structure containing said crimped yarn as at least a part
thereof.
Inventors: |
Mochizuki; Katsuhiko;
(Mishima, JP) ; Fukudome; Kousuke; (Mishima,
JP) ; Inoue; Shozo; (Okazaki, JP) ; Kimura;
Toshiaki; (Okazaki, JP) ; Narita; Syusaku;
(Otsu, JP) ; Shinozaki; Atsushi; (Fukui, JP)
; Kajiyama; Hiroshi; (Otsu, JP) ; Matsumura;
Kazuya; (Osaka, JP) |
Correspondence
Address: |
IP GROUP OF DLA PIPER US LLP
ONE LIBERTY PLACE, 1650 MARKET ST, SUITE 4900
PHILADELPHIA
PA
19103
US
|
Family ID: |
37962490 |
Appl. No.: |
12/083823 |
Filed: |
October 18, 2006 |
PCT Filed: |
October 18, 2006 |
PCT NO: |
PCT/JP2006/320700 |
371 Date: |
May 27, 2008 |
Current U.S.
Class: |
428/370 ;
264/168 |
Current CPC
Class: |
D02J 1/22 20130101; D02G
1/12 20130101; D02G 1/16 20130101; D02G 1/0266 20130101; D02G 1/161
20130101; D01F 8/12 20130101; D01F 8/14 20130101; D02G 1/20
20130101; Y10T 428/2924 20150115 |
Class at
Publication: |
428/370 ;
264/168 |
International
Class: |
D02G 3/04 20060101
D02G003/04; D01D 5/22 20060101 D01D005/22 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 19, 2005 |
JP |
2005-304036 |
Dec 26, 2005 |
JP |
2005-371657 |
Dec 26, 2005 |
JP |
2005-371658 |
Mar 1, 2006 |
JP |
2005-054234 |
Claims
1-33. (canceled)
34. A crimped yarn comprising a synthetic fiber comprising an
aliphatic polyester resin (A) and a thermoplastic polyamide resin
(B), wherein substantially no aliphatic polyester resin (A) is
exposed on a surface of the fiber, and a crimp is imparted to a
multifilament comprising said synthetic fiber.
35. The crimped yarn according to claim 34, wherein the synthetic
fiber has an exposed area ratio of the aliphatic polyester resin
(A) with respect to fiber surface area of 5% or less.
36. The crimped yarn according to claim 34, which is a BCF
yarn.
37. The crimped yarn according to claim 34, which is a crimped yarn
constituted of a polymer alloy type synthetic fiber containing the
aliphatic polyester resin (A) and the thermoplastic polyamide resin
(B), and has an sea/island structure in which the aliphatic
polyester resin (A) forms an island component and the thermoplastic
polyamide resin (B) forms a sea component and wherein the island
component has a domain size of 0.001 to 2 .mu.m.
38. The crimped yarn according to claim 37, wherein the aliphatic
polyester resin (A) is a crystalline resin and has a melting point
of 150 to 230.degree. C.
39. The crimped yarn according to claim 37, wherein the
thermoplastic polyamide resin (B) is a crystalline resin and has a
melting point of 150 to 250.degree. C.
40. The crimped yarn according to claim 37, wherein the aliphatic
polyester resin (A) and the thermoplastic polyamide resin (B) have
a blend ratio (weight ratio) of 5/95 to 55/45.
41. The crimped yarn according to claim 34, wherein a polymer alloy
containing the aliphatic polyester resin (A) and the thermoplastic
polyamide resin (B) further comprises compound (C) containing two
or more active hydrogen reactive groups in a molecule.
42. The crimped yarn according to claim 41, wherein the active
hydrogen reactive group is at least one selected from the group
consisting of glycidyl group, oxazoline group, carbodiimide group
and acid anhydride group.
43. The crimped yarn according to claim 41, containing 0.005 to 5
wt % of the compound (C) with respect to the total amount of the
aliphatic polyester resin (A), the thermoplastic polyamide resin
(B) and the compound (C).
44. The crimped yarn according to claim 37, further comprising
grooves extending in a fiber axis direction formed on at least a
portion of a surface of the synthetic fiber and a width of said
groove(s) is(are) 0.01 to 1 .mu.m.
45. The crimped yarn according to claim 44, wherein an aspect ratio
of the groove (longitudinal axis length of groove/width of groove)
is 10 to 500.
46. The crimped yarn according to claim 37, wherein the crimped
yarn satisfies the following physical properties: Strength: 1
cN/dtex or more Crimp elongation percentage after boiling water
treatment: 3 to 30% Non-circularity (D1/D2): 1.2 to 7.
47. The crimped yarn according to claim 37, further comprising 0.01
to 2 wt % of at least one kind crystal nucleating agent selected
from the group consisting of talc, a sorbitol derivative, a metal
salt of phosphoric acid ester, a basic inorganic aluminum compound
and a salt of melamine compound with respect to the aliphatic
polyester resin (A).
48. A method of producing a crimped yarn comprising: kneading an
aliphatic polyester resin (A) and a thermoplastic polyamide resin
(B) in a blend ratio (weight ratio) of 5/95 to 55/45 such that a
ratio of melt viscosity (.eta.b/.eta.a) (wherein, .eta.a: melt
viscosity of the aliphatic polyester resin (A), .eta.b: melt
viscosity of the thermoplastic polyamide resin (B)) is in the range
of 0.1 to 2; melt spinning the resin at a spinning temperature of,
provided that the melting point of the thermoplastic polyamide
resin (B) is Tmb, Tmb+3.degree. C. to Tmb+40.degree. C., to thereby
form a multifilament at a linear discharge velocity in a spinning
hole of a spinneret of 0.02 to 0.4 m/sec; cooling the multifilament
by setting a starting point of cooling substantially vertically
beneath 0.01 to 0.15 m from a surface of the spinneret and applying
a gas to the filament from substantially a right angle at a
velocity of 0.3 to 1 m/sec and at a temperature of 15 to 25.degree.
C.; covering the multifilament with a finishing agent for spinning;
stretching the filament in 1 to 3 stages while heating the filament
with hot rolls of 50 to 130.degree. C. such that an elongation at
break of the multifilament is 15 to 65%; heat setting the filament
by setting a final roll temperature after stretching at such that a
melting point of the aliphatic polyester resin (A) is Tma, Tma-30
to Tma+30.degree. C.; feeding the filament to an air-jet stuffing
machine and subjecting the filament to crimp processing by setting
a nozzle temperature of said machine to 5 to 100.degree. C. higher
than a final roll after stretching, to thereby form a
3-dimensionally crimped yarn, and contacting the crimped yarn with
a cooling drum and winding the crimped yarn at a speed 10 to 30%
lower than that of the final roll after stretching.
49. The method according to claim 48, further comprising adding a
compound (C) containing two or more active hydrogen reactive groups
in a molecule to the aliphatic polyester resin (A) and/or the
thermoplastic polyamide resin (B) as a compatibilizer, melting the
resulting mixture and kneading the resulting melted mixture.
50. The method according to claim 48, wherein the compound (C) is
added in an amount of 0.005 to 5 wt % with respect to the total
amount of the aliphatic polyester resin (A), the thermoplastic
polyamide resin (B) and the compound (C).
51. The method according to claim 48, further comprising adding at
least one kind crystal nucleating agent selected from the group
consisting of talc, a sorbitol derivative, a metal salt of
phosphoric acid ester, a basic inorganic aluminum compound, a salt
of melamine compound to the aliphatic polyester resin (A) and/or
the thermoplastic polyamide resin (B) and melt kneading the
resulting mixture.
52. The method according to claim 51, adding 0.01 to 2 wt % of at
least one kind crystal nucleating agent selected from the group
consisting of talc, a sorbitol derivative, a metal salt of
phosphoric acid ester, a basic inorganic aluminum compound and a
salt of melamine compound with respect to the aliphatic polyester
resin (A) to the mixture.
53. The crimped yarn according to claim 34, wherein the crimped
yarn comprises a sheath/core type composite fiber of which a core
component comprises the aliphatic polyester resin (A) or a polymer
alloy of the aliphatic polyester resin (A) and the thermoplastic
polyamide resin (B) and a sheath component comprise the
thermoplastic polyamide resin (B), and the following physical
properties (1) to (3) are satisfied: (1) Strength: 1.5 to 3
cN/dtex. 2) Single fiber thickness: 5 to 40 dtex. 3) Boiling water
shrinkage: 6% or less.
54. The crimped yarn according to claim 53, wherein a total heat
capacity of melting peak of differential calorimetric curve
measured for the crimped yarn at a heating rate of 16.degree.
C./min is 50 J/g or more.
55. The crimped yarn according to claim 53, wherein the composite
fiber has a sheath/core ratio (weight ratio) is 10/90 to 65/35.
56. The crimped yarn according to claim 53, wherein a
non-circularity (D3/D4) of a single fiber of the crimped yarn is
1.3 to 4.
57. The crimped yarn according to claim 53, wherein a crimp
elongation percentage after boiling water treatment of the crimped
yarn is 5 to 35%.
58. The crimped yarn according to claim 53, wherein a crimp
elongation percentage measured after boiling water treatment under
a load of 2 mg/dtex (elongation percentage under load) is 2 to
30%.
59. The crimped yarn according to claim 53, wherein a blend ratio
(weight ratio) of the aliphatic polyester resin (A) and the
thermoplastic polyamide resin (B) of the core component is 95/5 to
20/80.
60. The sheath/core type composite fiber according to claim 59,
wherein an alloy structure of a polymer alloy of the core component
satisfies the following (1) to (3): (1) The aliphatic polyester
resin (A) forms the island component. 2) The thermoplastic
polyamide resin (B) forms the sea component. 3) A diameter of the
island component is 0.001 to 2 .mu.m.
61. A method of producing a crimped yarn comprising: joining an
aliphatic polyester resin (A) as a core component and a
thermoplastic polyamide resin (B) as a sheath component in a
spinning hole of a spinneret; discharging the components to thereby
form a spun yarn; stretching the spun yarn at a total stretching
ratio of 2 to 5; heat setting the spun yarn at a final roll
temperature after stretching at 160 to 220.degree. C.; and
subjecting the spun yarn to a crimp processing by an air stuffer
crimp processing machine.
62. A method of producing a crimped yarn comprising: joining an
aliphatic polyester resin (A) as a core component and a
thermoplastic polyamide resin (B) as a sheath component in a weight
ratio of the core component of 10 to 65 wt %; discharging the
joined resin through a spinning hole of a spinneret such that a
melt viscosity ratio (.eta.b/.eta.a) is in a range of 0.2 to 2;
melt spinning the joined resin at a selected spinning temperature
wherein the melting point of the thermoplastic polyamide resin (B)
is Tmb, Tmb to Tmb+30.degree. C. and linear discharge velocity in
the spinning hole of the spinneret is 1 to 20 m/min to thereby form
a spun yarn; cooling the spun yarn by setting a starting point of
cooling vertically beneath 0.01 to 0.15 m from a surface of the
spinneret and applying a gas at a wind speed 0.3 to 1 m/sec and a
wind temperature of 15 to 25.degree. C. from a right angle to a
perpendicular direction to the spinneret surface to obtain a
multifilament; stretching the multifilament in 2 stages at a total
stretching ratio of 2 to 5; subjecting the multifilament to a crimp
processing and adjusting a first stage stretching roll to 50 to
90.degree. C., a second stage stretching roll to 90 to 150.degree.
C. and a final roll after stretching to 160 to 220.degree. C. to
heat set the multifilament; subjecting the multifilament to an air
jet stuffer crimp processing machine carried out by setting a
nozzle temperature of the machine to a temperature 5 to 100.degree.
C. higher than the final roll temperature to thereby form a crimped
yarn; contacting the crimped yarn with a cooling drum; and winding
the crimped yarn at a speed 10 to 30% lower than the final roll
after stretching.
63. A method of producing a crimped yarn comprising: forming a core
component comprising a polymer alloy obtained by melt kneading an
aliphatic polyester resin (A) and a thermoplastic polyamide resin
(B) as a core component with a twin screw extruding/kneading
machine and/or a single screw extruding/kneading machine, in a
range of kneading temperature of from a melting point of the
thermoplastic polyamide resin (B), (Tmb), to Tmb+40.degree. C., at
a shear rate of 200 to 20,000 sec.sup.-1 and a residence time of
0.5 to 30 minutes, and a sheath component comprising a
thermoplastic polyamide resin (B); and joining the resins in a
spinneret and discharging a composite fiber formed by the
spinneret.
Description
RELATED APPLICATIONS
[0001] This is a .sctn.371 of International Application No.
PCT/JP2006/320700, with an international filing date of Oct. 18,
2006 (WO 2007/046397 A1, published Apr. 26, 2007), which is based
on Japanese Patent Application Nos. 2005-304036, filed Oct. 19,
2005, 2005-371657, filed Dec. 26, 2005, 2005-371658, filed Dec. 26,
2005, and 2006-054234, filed Mar. 1, 2006.
TECHNICAL FIELD
[0002] This disclosure relates to crimped yarns constituted of a
synthetic fiber comprising an aliphatic polyester resin and a
thermoplastic polyamide resin in which the exposed area ratio of
the aliphatic polyester resin with respect to the fiber surface
area is extremely small.
BACKGROUND
[0003] Recently along with the increased concern to the environment
in global scale, development of fiber material decomposable in
natural environment has been strongly desired. For example, since
the main starting material of conventional general purpose plastics
is petroleum resource, it has become a big problem that the
petroleum resource would be dried up in future, or that the global
warning is caused by mass consumption of the petroleum
resource.
[0004] For that reason, in recent years, research and development
of various plastics and fibers such as of aliphatic polyesters are
activated. Among them, fibers made from plastics which can be
decomposed by microorganism, i.e., biodegradable plastics have
drawn attention.
[0005] In addition, by making plant resources as starting materials
which take in carbon dioxide from the air to grow, not only it is
expected to be able to control the global warming by circulation of
carbon dioxide, but also it may be possible to solve the problem of
the shortage of resources. For that reason, plastics of which
starting materials are plant resources, i.e., plastics made by
biomass have been drawing attention.
[0006] So far, biodegradable plastics made by biomass has problems
that not only their mechanical properties and heat resistance are
poor, but also their production cost is high, and they have not
been used as general purpose plastics. On the other hand, in recent
years, as a biodegradable plastic of which mechanical properties
and heat resistance are relatively high and its production cost is
low, polylactic acid of which starting material is lactic acid
obtainable by fermentation of starch is in the spotlight.
[0007] Aliphatic polyester resins represented by polylactic acid
have been used for a long time, for example, in medical field as a
sewing thread for surgical operation, but recently, by an
improvement of its mass production technology, it became possible
to compete in cost with other general purpose plastics.
Accordingly, development of its commercial product as a fiber has
been activated.
[0008] As developments of aliphatic polyester fibers such as of
polylactic acid fiber, by taking advantage of its biodegradability,
agricultural materials, civil engineering materials or the like are
going ahead. Following those, as big scale applications, apparel
applications, interior applications such as curtain or carpet,
automotive interior applications and industrial material
applications are also expected. However, when it is used to the
apparel applications or industrial material applications, the poor
abrasion resistance of the aliphatic polyester, especially
polylactic acid becomes a big problem.
[0009] For example, in case where polylactic acid fiber is used for
apparel uses, the fiber have been found to be poor in practical
durability such that a color staining occurs easily by a rubbing or
the like or, and in a serious case, fiber becomes whitish by a
fibrillation or, it is excessively stimulative to skin. In the case
where it is used for car interior, especially for carpet which
suffers from hard rubbing, as well as a falling down of pile of
polylactic acid easily occurs, weaving also occurs, and in a
serious case, a hole may be opened. Since aliphatic polyester
(especially, polylactic acid) easily be hydrolyzed also, the
fibrillation or weaving such as above-mentioned becomes serious
with lapse of time, and it have been found that its product life is
short.
[0010] As methods for improving abrasion resistance of polylactic
acid, for example, there are methods by preventing hydrolysis, for
example, a method of preventing hydrolysis at fiber production
process by decreasing water content of polylactic acid as low as
possible or, a method of improving hydrolysis resistance by adding
a monocarbodiimide compound. However, in any method of them,
although the lowering of abrasion resistance is prevented from the
view point that an embrittlement of polylactic acid with the lapse
of time is prevented, any of them is not a method of changing the
characteristic of polylactic acid that it is easily fibrillated,
i.e., it was found that every of them can prevent an embrittlement
with the lapse of time, but initial abrasion resistance has not
been improved from the conventional one.
[0011] As a method of greatly improving abrasion resistance, there
is a method of preventing abrasion by decreasing friction
coefficient of fiber surface by imparting a lubricant such as
aliphatic acid bisamides. However, although such a fiber is
effective in a case where an external force is small but, for
example, in a case where a big weight is added as a case of carpet,
since cohesion between fibers cannot be sufficiently prevented,
polylactic acid is broken and its use is limited.
[0012] A technique of improving mechanical characteristics of resin
composition by blending polyamide and aliphatic polyester is
disclosed (JP 2003-238775 A (page 3)). According to the method
described in JP 2003-238775 A (page 3), it is mentioned that, by
reinforcing effect of polyamide, mechanical characteristics such as
strength, heat resistance and abrasion resistance are increased
but, in the method, since the polyamide is a minor component such
that its blend ratio is 5 to 40%, the aliphatic polyester forms sea
component and, furthermore, since the aliphatic polyester and the
polyamide are incompatible and an adhesion force of the interface
between these phases is poor, it was found there are problems that
the interface is easily peeled off by an external force to become
whitish by fibrillation and abrasion speed is also high.
[0013] Furthermore, a technique is disclosed that a high elongation
polyamide fiber is prepared by micro-dispersing a polyester in a
polyamide to prevent orientation (JP 2005-206961 A (page 3)). By
making it into the polymer alloy fiber, it becomes possible to
impart a high bulkiness to a crimped yarn by mixing with a low
elongation polyamide unstretched yarn at false twist processing.
However, although the polymer alloy fiber is suitable for a sheath
yarn at the false twist processing, when it is used for production
of an air stuffer crimped yarn, since fiber orientation is rather
insufficient, heat shrinkage in the air stuffer crimping machine is
insufficient and a 3 dimensional crimp is not developed and only a
crimped yarn of which crimp elongation percentage is low can be
obtained.
[0014] Furthermore, a composite fiber of which abrasion resistance
is improved by arranging a polyamide of which abrasion resistance
is high as the sheath component, is disclosed (JP 2004-36035 A
(scope of claims)). By this technique, it is possible to greatly
prevent weaving of fiber. However, in a case where a composite
fiber is made, it was found that a new problem arises that, at a
later stage processing step or when used as a product, external
force is concentrated to the interface between the core component
and the sheath component (hereafter, referred to as sheath/core
interface) of which adhesion force is low, and the sheath/core
interface is peeled off and causes an appearance change (becomes
whitish). Once the sheath/core interface is peeled off, the peeling
extends along fiber longitudinal direction and defects like white
streaks are observed sometimes. This is a defect in an application
in which, especially, appearance is important. Also, there was a
problem that, when a peeling between the sheath/core interface
arises, the sheath component is split (hereafter, referred to as
sheath split), due to an abrasion between the core component and
the sheath component and further, it grows to a fibrillation.
[0015] In JP 2004-36035 A (scope of claims), a composite fiber of
which abrasion resistance is improved by having a thermoplastic
polyamide of a specified thickness as sheath component is
disclosed. The composite fiber exhibits an effect in applications
exposed only to relative weak abrasions such as apparel uses.
However, in applications exposed to strong external force
repeatedly such as carpet or the like, a pealing of the interface
occurs easily and an appearance change was easy to occur. In JP
2004-36035 A (scope of claims), a crimped yarn (false twisted yarn)
in which the composite fiber is used is disclosed, but it was found
that a crimped yarn comprising the composite fiber is easier to be
peeled off at its sheath/core interface than an uncrimped yarn.
Furthermore, its peeling resistance may deteriorate according to
the change of aliphatic polyester with the lapse of time, and
although the composite fiber in which a polyamide is disposed as a
sheath component was excellent in abrasion resistance, its peeling
resistance was insufficient, and had a defect that an appearance of
its product was easy to change.
[0016] It could accordingly be advantageous to provide a crimped
yarn and a fiber structure excellent in abrasion resistance as well
as excellent in aesthetic appearance after dyeing, constituted of a
synthetic fiber comprising an aliphatic polyester resin and a
thermoplastic polyamide resin.
[0017] We provide crimped yarns including a synthetic fiber
comprising an aliphatic polyester resin (A) and a thermoplastic
polyamide resin (B) with an exposed area ratio of the aliphatic
polyester resin (A) with respect to the fiber surface area of 5% or
less, and a crimp is imparted to a multifilament comprising the
synthetic fiber. We also provide fiber structures comprising the
crimped yarn in at least a portion thereof.
[0018] It is thus possible to provide a synthetic fiber and a fiber
structure which is most suitable for general apparel applications
or industrial material applications of which abrasion resistance is
greatly improved and capable of providing high quality fiber
structure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a photograph of a transmission electron microscope
(TEM) that explains the sea/island structure of a polymer alloy
fiber.
[0020] FIG. 2 is a photograph of a scanning electron microscope
(SEM) of a fiber surface layer of a crimped yarn (Example 1).
[0021] FIG. 3 is a schematic view explaining the aspect ratio of a
groove formed on fiber surface layer of the crimped yarn.
[0022] FIG. 4 is a photograph of a fiber configuration observed
from the upper side of an embodiment of BCF yarn placed on black
paper in a multifilament state.
[0023] FIG. 5 is a photograph of a fiber configuration observed
from the upper side of an embodiment of BCF yarn placed on black
paper in a state separated into single fibers.
[0024] FIG. 6 is a schematic view of a direct
spinning-stretching-crimp processing machine preferably used for
producing a crimped yarn constituted of a polymer alloy type
synthetic fiber.
[0025] FIG. 7 is a schematic view that shows hole depth, slit
length and slit width of spinning hole, and spinning hole diameter
of a spinneret in the production method.
[0026] FIG. 8 is a schematic view showing the starting point of
cooling in the production method.
[0027] FIG. 9 is a schematic view of a direct
spinning-stretching-crimp processing machine preferably used for
producing a crimped yarn comprising the sheath/core type composite
fiber (core component: aliphatic polyester resin).
[0028] FIG. 10 shows preferable examples of the cross-sectional
shape of the sheath/core type composite fiber.
[0029] FIG. 11 is a drawing showing the relation between melt
viscosity and relative viscosity.
[0030] FIG. 12 shows a longitudinal-sectional view showing a
representative spinneret used in the method.
[0031] FIG. 13 is a schematic view of a representative false twist
processing machine of Example 52.
[0032] FIG. 14 is a schematic view of a direct
spinning.cndot.stretching.cndot.crimp processing machine preferably
used for producing a crimped yarn constituted of the sheath/core
type composite fiber (core component: polymer alloy).
EXPLANATION OF CODES
[0033] 1: Spinning hopper [0034] 2: Twin screw extruding/kneading
machine [0035] 3: Spinning block [0036] 4: Spinning pack [0037] 5:
Spinneret [0038] 6: Circular chimney (yam cooling apparatus) [0039]
7: Yarn [0040] 8: Oiling device 1 [0041] 9: Oiling device 2 [0042]
10: Stretch roll [0043] 11: First heating roll (1 FR) [0044] 12:
Second heating roll (1 DR) [0045] 13: Third heating roll (2 DR)
[0046] 14: Air jet stuffer machine [0047] 15: Cooling roll [0048]
16: Tension measuring detector [0049] 17: take-up roll [0050] 18:
Interlacing nozzle [0051] 19: Winder [0052] 20: Cooling air
blow-off area [0053] 21, 65: Core component hopper [0054] 22, 66:
Sheath component hopper [0055] 23: Single screw extruding/kneading
machine of core component side [0056] 24: Single screw
extruding/kneading machine of sheath component side [0057] 25, 69:
Spinning block [0058] 26, 70: Gear pump of core component side
(metering pump) [0059] 27, 71: Gear pump of sheath component side
(metering pump) [0060] 28, 72: Spinning pack [0061] 29, 73:
Spinneret [0062] 30, 74: Uniflow cooling apparatus [0063] 31, 75:
Yarn [0064] 32, 76: Oiling device [0065] 33, 77: First roll [0066]
34, 78: Second roll [0067] 35, 79: Third roll [0068] 36, 80: Fourth
roll [0069] 37, 81: Crimp nozzle [0070] 38, 82: Cooling roll [0071]
39, 83: Sixth roll [0072] 40, 84: Seventh roll [0073] 41, 85:
Cheese package [0074] 42, 86: Winder [0075] 43: Core component
[0076] 44: Sheath component [0077] 45: Spinneret 1 (spinneret
having separate flow channels for core component and sheath
component) [0078] 46: Spinneret 2 (spinneret just before discharge)
[0079] 47: Interlacing nozzle [0080] 48: Stretched yarn cheese
[0081] 49, 51, 52, 55, 61: Yarn guide [0082] 50: Yarn [0083] 53:
Feed roll [0084] 54: First heater [0085] 56: Cooling plate [0086]
57: Three axis type twister [0087] 58: Stretch roll [0088] 59:
Second heater [0089] 60: Delivery roll [0090] 62: Interlacing
nozzle [0091] 63: Yarn guide [0092] 64: False twisted yarn [0093]
67: Twin screw extruding/kneading machine of core component side
[0094] 68: Twin screw extruding/kneading machine of sheath
component side
DETAILED DESCRIPTION
[0095] The aliphatic polyester resin (A) (hereafter, may be
referred to as "component A") is a polymer of which aliphatic alkyl
chain is connected with an ester bond. As the aliphatic polyester
resin (A), it is preferable to be crystalline and it is more
preferable that its melting point is 150 to 230.degree. C. As kinds
the aliphatic polyester resin (A), for example, polylactic acid,
polyhydroxybutyrate, polybutylene succinate, polyglycolic acid,
polycaprolactone or the like are mentioned. Polylactic acid is most
preferable among the aliphatic polyesters since its melting point
is high and excellent in thermal stability.
[0096] The above-mentioned polylactic acid is a polymer having
--(O--CHCH.sub.3--CO).sub.n-- as its repeating unit, and it is a
polymerization product of lactic acid or oligomer of lactic acid
such as lactide. Since there are two kinds of optical isomer of
lactic acid, D-lactic acid and L-lactic acid, as their polymers,
there are poly(D-lactic acid) consisting only of D-type and
poly(L-lactic acid) consisting only of L-type and polylactic acid
consisting of both of them. Regarding the optical purity of
D-lactic acid or L-lactic acid in polylactic acid, as it decreases,
crystallinity decreases and melting point depression becomes large.
To keep the heat resistance of fiber, it is preferable that the
melting point is higher than 150.degree. C. or more, and to be
160.degree. C. or more is more preferable. Still more preferably,
it is 170.degree. C. or more and especially preferably 180.degree.
C. or more.
[0097] However, other than the system in which the two kinds of
optical isomers are simply mixed as stated above, after the
above-mentioned two kinds of optical isomers are blended and formed
into a fiber, if it is subjected to a high temperature heat
treatment of 140.degree. C. or higher to convert them into a stereo
complex in which a racemic crystalline is formed, the melting point
can be made as high as 220 to 230.degree. C., and it is preferable.
In such cases, the "component A" means a mixture of poly(L lactic
acid) and poly(D lactic acid), and when its blend ratio is 40/60 to
60/40, it is best since it can increase ratio of the stereo complex
crystal. It is preferable to add a crystal nucleating agent at melt
spinning to form the stereo complex crystal efficiently. As the
crystal nucleating agents, other than talc or stratified clay
minerals, stearic acid or 12-hydroxystearic acid, stearic acid
amide or oleic acid amide, erucic acid amide, methylene bisstearic
acid amide, ethylene bisstearic acid amide, ethylene bisoleic acid
amide, butyl stearate, stearic acid monoglyceride, calcium
stearate, zinc stearate, magnesium stearate, lead stearate, etc.,
of which compatibility with polylactic acid is high can be
applied.
[0098] Furthermore, there is a residual lactide in polylactic acid
as a low molecular weight residue, but this low molecular weight
residue may become a reason which induces thermal heater stain in
stretching or bulking process, or dyeing abnormalities such as
dyeing unevenness in dyeing processing step. It may accelerate
hydrolysis of fiber or fiber product to thereby decrease their
durability. Therefore, it is preferable that amount of residual
lactide in polylactic acid is 0.3 wt % or less, more preferably 0.1
wt % or less, and still more preferably 0.03 wt % or less.
[0099] The component A may, for example in a range which does not
impair the property of polylactic acid, be a copolymer in which a
component other than lactic acid is copolymerized. As a component
to be copolymerized, polyalkylene ether glycols such as
polyethylene glycol, aliphatic polyesters such as polybutylene
succinate or polyglycolic acid, aromatic polyesters such as
polyethylene isophthalate, and ester bond formable monomers such as
hydroxycarboxylic acid, lactone, dicarboxylic acid or diol, are
mentioned. Among them, polyalkylene ether glycols, of which
compatibility with the thermoplastic polyamide resin (B)
(hereafter, may be referred to as "component B") is good, is
preferable. A copolymerization ratio of such copolymerization
component is, in a range not being impaired by a decrease of heat
resistance due to a melting point depression, preferably 0.1 to 10
mol % with respect to the polylactic acid.
[0100] To the component A, as a modifier, a particle, a color
pigment, a crystal nucleating agent, a flame retardant, a
plasticizer, an anti-static agent, an antioxidant, an ultraviolet
absorber, a lubricant, etc., may further be added. As the color
pigments, other than inorganic pigments such as carbon black,
titanium oxide, zinc oxide, barium sulfate and iron oxide, organic
pigments such as a cyanine-based, a styrene-based, a
phthalocyanine-based, an anthraquinone-based, a perinone-based, an
isoindolinone-based, a quinophthalone-based, a quinocridone-based
and a thioindigo-based one can be used. Similarly, modifiers such
as particles such as various inorganic particles including calcium
carbonate, silica, silicone nitride, clay, talc, kaolin, zirconic
acid, etc., cross-linked polymer particles or various metallic
particles can also be used. Furthermore, polymers such as waxes,
silicone oils, various surfactants, various fluororesins,
polyphenylene sulfides, polyamides, polyacrylates including
ethylene/acrylate copolymer and methyl methacrylate polymer,
various rubbers, ionomers, polyurethanes and their thermoplastic
elastomers, can be contained in a small amount.
[0101] As the lubricant preferably used in the above-mentioned
component A, aliphatic acid amides and/or aliphatic acid esters are
mentioned. As the aliphatic acid amides, for example, lauric acid
amide, palmitic acid amide, stearic acid amide, erucic acid amide,
behenic acid amide, methylol stearic acid amide, methylol behenic
acid amide, dimethylol oil amide, dimethyl lauric acid amide,
dimethyl stearic acid amide, compounds containing two amide bond in
one molecule such as saturated aliphatic acid bisamide, unsaturated
aliphatic acid bisamide or aromatic-based bisamide are mentioned,
for example, methylene biscaprylic acid amide, methylene biscapric
acid amide, methylene bislauric acid amide, methylene bismyristic
acid amide, methylene bispalmitic acid amide, methylene bisstearic
acid amide, methylene bisisostearic acid amide, methylene
bisbehenic acid amide, methylene bisoleic acid amide, methylene
biserucic acid amide, ethylene biscaprylic acid amide, ethylene
biscapric acid amide, ethylene bislauric acid amide, ethylene
bismyristic acid amide, ethylene bispalmitic acid amide, ethylene
bisstearic acid amide, ethylene bisisostearic acid amide, ethylene
bisbehenic acid amide, ethylene bisoleic acid amide, ethylene
biserucic acid amide, butylene bisstearic acid amide, butylene
bisbehenic acid amide, butylene bisoleic acid amide, butylene
biserucic acid amide, hexamethylene bisstearic acid amide,
hexamethylene bisbehenic acid amide, hexamethylene bisoleic acid
amide, hexamethylene biserucic acid amide, m-xylilene bisstearic
acid amide, m-xylilene bis-12-hydroxystearic acid amide, p-xylilene
bisstearic acid amide, p-phenylene-bisstearic acid amide,
p-phenylene-bisstearic acid amide, N,N'-distearyl adipic acid
amide, N,N'-distearyl sebacic acid amide, N,N'-dioleyl adipic acid
amide, N,N'-dioleyl sebacic acid amide, N,N'-distearyl isophthalic
acid amide, N,N'-distearyl terephthalic acid amide, methylene
bishydroxystearic acid amide, ethylene bishydroxystearic acid
amide, butylene bishydroxystearic acid amide and hexamethylene
bishydroxystearic acid amide, etc., are mentioned, and other than
that, as alkyl substituted type aliphatic acid monoamide, compounds
such as saturated aliphatic acid monoamide or unsaturated aliphatic
acid monoamide of which amide hydrogen is substituted with alkyl
group, for example, N-lauryl lauric acid amide, N-palmityl palmitic
acid amide, N-stearyl stearic acid amide, N-benenyl behenic acid
amide, N-oleyl oleic acid amide, N-stearyl oleic acid amide,
N-oleyl stearic acid amide, N-stearyl erucic acid amide, N-oleyl
palmitic acid amide or the like are mentioned. In the alkyl group,
a substituent such as hydroxyl group may be introduced in its
structure, for example, methylol stearic acid amide, methylol
behenic acid amide, N-stearyl-12-hydroxystearic acid amide, N-oleyl
12-hydroxystearic acid amide or the like are included in the alkyl
substituted type aliphatic acid monoamide.
[0102] As aliphatic acid esters, for example, aliphatic
monocarboxylic acid esters such as lauric acid cetyl ester, lauric
acid phenacyl ester, myristic acid cetyl ester, myristic acid
phenacyl ester, palmitic acid isopropylidene ester, palmitic acid
dodecyl ester, palmitic acid tetradodecyl ester, palmitic acid
pentadecyl ester, palmitic acid octadecyl ester, palmitic acid
cetyl ester, palmitic acid phenyl ester, palmitic acid phenacyl
ester, stearic acid, cetyl ester or behenic acid ethyl ester;
monoesters of ethylene glycol such as glycol monolaurate, glycol
monopalmitate or glycol monostearate, diesters of ethylene glycol
such as glycol dilaurate, glycol dipalmitate or glycol distearate;
monoesters of glycerin such as glycerin monolaurate, glycerin
monomyristate, glycerin monopalmitate or glycerin monostearate;
diesters of glycerin such as glycerin dilaurate, glycerin
dimyristate, glycerin dipalmitate or glycerin distearate; triesters
of glycerin such as glycerin trilaurate, glycerin trimyristate,
glycerin tripalmitate, glycerin tristearate, palmitodiolein,
palmitodistearin or oleodistearin, etc., are mentioned.
[0103] Among these compounds, it is preferable to use aliphatic
acid bisamide or alkyl substituted type aliphatic acid monoamide.
Aliphatic acid bisamide or alkyl substituted type aliphatic acid
monoamide has a low reactivity of its amide compared to ordinary
aliphatic acid monoamide to thereby hardly cause a reaction with
polylactic acid at melt molding, and further, since there are many
such monoamides of high molecular weight, heat resistance is high
and hardly sublimates, and accordingly, it exhibits an excellent
slipperiness without impairing its function as a lubricant. In
particular, since aliphatic acid bisamide has a lower reactivity of
its amide, it can be more preferably used, and ethylene bisstearic
acid amide is still more preferable.
[0104] Furthermore, 2 kinds or more of the aliphatic acid amide and
the aliphatic acid ester may be used, and the aliphatic acid amide
and the aliphatic acid ester may be used together.
[0105] It is necessary that a content of the aliphatic acid amide
and/or aliphatic acid ester is 0.1 wt % or more with respect to
fiber weight to exhibit the above-mentioned characteristics. It is
preferable that the content is 5 wt % or less since, when the
content is too high, mechanical properties of fiber may deteriorate
or its color tone may turn worse such that it become yellowish when
dyed. More preferable content of the aliphatic acid amide and/or
aliphatic acid ester is 0.2 to 4 wt % and, still more preferably,
it is 0.3 to 3 wt %.
[0106] Furthermore, it is preferable that a molecular weight of
polylactic acid polymer is high to improve abrasion resistance, but
when the molecular weight is too high, moldability at melt spinning
or stretchability may deteriorate. It is preferable that the weight
average molecular weight is 80,000 or more to keep abrasion
resistance, 100,000 or more is more preferable. Still more
preferably, it is 120,000 or more. On the other hand, when the
molecular weight exceeds 350,000, since stretchability deteriorates
as above-mentioned, molecular orientation is impaired and fiber
strength may decrease, as a result. Accordingly, it is preferable
that a weight average molecular weight is 350,000 or less, 300,000
or less is more preferable. Still more preferably, it is 250,000 or
less. The above-mentioned weight average molecular weight is a
value measured by a gel permeation chromatography (GPC) and
determined by being converted into the polystyrene equivalent.
[0107] A production method of polylactic acid preferably used as
the component A is not especially limited, but in concrete, a
direct dehydrative condensation method in which lactic acid is
subjected to a dehydrative condensation as it is under a presence
of an organic solvent and a catalyst (refer to JP-H6-65360A), a
method of subjecting at least 2 kinds of homopolymer to a
copolymerization and ester interchange reaction under a presence of
polymerization catalyst (refer to JP-H7-173266A), furthermore, an
indirect polymerization method in which lactic acid is once
dehydrated to be converted to cyclic dimer and subjected to a ring
opening polymerization (refer to the specification of U.S. Pat. No.
2,703,316) are mentioned.
[0108] The thermoplastic polyamide resin (B) is a polymer having an
amide bond and as the thermoplastic polyamide resin (B), for
example, polycapramide (nylon 6), polytetramethylene adipamide
(nylon 46), polyhexamethylene adipamide (nylon 66), polyundecane
amide (nylon 11), polydodecane amide (nylon 12), polyhexamethylene
sebacamide (nylon 610), polypentamethylene sebacamide (nylon 510),
etc., can be mentioned. Among them, in view of raw material cost,
nylon 6 is preferable and, to increase adhesion force of interface
by increasing compatibility with the component A, it is preferable
that methylene chain length of polyamide is long, and in that
point, nylon 11, nylon 12, nylon 610 or nylon 510 are preferable.
In view of providing a material for reducing environmental load,
nylon 610 or nylon 510 of which monomer is sebacic acid which is a
nonpetroleum raw material is preferable. The polyamide may be a
homopolymer or a copolymer. To the component B, a particle, a flame
retardant, an antistatic agent or the above-mentioned lubricant
preferably used in the component A, etc., may be added. Solution
viscosity of the thermoplastic polyamide can be measured by known
methods, such that, in the case of nylon 6, nylon 610 or the like,
it is measured by using 98% sulfuric acid solution mentioned later,
and an inherent viscosity of nylon 11 is measured by using m-crezol
solution.
[0109] Furthermore, in general, aliphatic polyesters cannot be said
to be high in heat resistance such that, the melting point is
usually 200.degree. C. or less even when it has a melting point,
and when it is melted and stored at a temperature exceeding
250.degree. C., its physical properties may deteriorate rapidly.
For that reason, it is preferable that a melting point of the
thermoplastic polyamide resin (B) to be blended is 150 to
250.degree. C., and 150 to 225.degree. C. is more preferable. Still
more preferably, it is 150 to 205.degree. C. However, in
consideration of heat resistance of crimped yarn, it is preferable
that melting point of the thermoplastic polyamide resin (B) is
higher than that of the aliphatic polyester (A). The thermoplastic
polyamide resin may be a copolymer as above-mentioned, but it is
preferable to be crystalline since its abrasion resistance may be
lowered with lowering of its crystallinity.
[0110] Regarding the presence or absence of crystallinity, it can
be decided that the polymer is crystalline when a melting peak can
be observed by a differential scanning colorimeter (DSC). The
higher the crystallinity, the more preferable, and it can be
evaluated by crystal melting peak calorie in DSC, as its index. The
crystal melting peak calorie .DELTA.H is preferably 30 J/g, more
preferably 40 J/g and still more preferably, 60 J/g.
[0111] The crimped yarn includes the above-mentioned synthetic
fiber comprising the aliphatic polyester resin (A) and the
thermoplastic polyamide resin (B) and almost no aliphatic polyester
resin (A) is exposed on fiber surface, and it is preferable that an
exposed area ratio of the aliphatic polyester resin (A) with
respect to fiber surface area is 5% or less. As structures having
such fiber surface configuration can be achieved by any one of (1)
or (2) of (1) "polymer alloy type synthetic fiber having an
sea/island structure in which the aliphatic polyester resin (A)
forms the island component and the thermoplastic polyamide resin
(B) forms the sea component," or (2) "sheath/core type composite
fiber of which core component is the aliphatic polyester resin (A)
or a polymer alloy of the aliphatic polyester resin (A) and the
thermoplastic polyamide resin (B), and the sheath component is the
thermoplastic polyamide resin (B)." Regarding preferable
embodiments of these (1) and (2) are described in the
following.
[0112] At first, the "polymer alloy type synthetic fiber having an
sea/island structure in which the aliphatic polyester resin (A)
forms the island component and the thermoplastic polyamide resin
(B) forms the sea component," which is one of preferable examples,
is explained.
[0113] In the case of a synthetic fiber where the component A and
the component B are blended to be made into a polymer alloy, blend
ratio is not especially limited, but to make a polymer alloy having
an sea/island structure in which the component A is the island
component, and the component B is the sea component, it is
preferable that a blend ratio (wt %) of component A/component B is
in the range of 5/95 to 55/45. In the case where the ratio of
component A is increased, it is necessary to increase melt
viscosity of the component A, .eta.a, and in the case where the
ratio component B is increased, it is necessary to increase melt
viscosity of the component B, .eta.b.
[0114] Furthermore, in the case of the polymer alloy type synthetic
fiber, it is necessary to make a polymer alloy in which the
component A is the island component and the component B is the sea
component. Accordingly, a blend ratio of the component A and the
component B is, since the higher the ratio of the component B, the
easier to make the polymer alloy, more preferably, 10/90 to 45/55,
still more preferably, 15/85 to 40/60, most preferably, 20/80 to
35/65. It is preferable to control a ratio of melt viscosity
(.eta.b/.eta.a) into the range of 0.1 to 2. More preferably, it is
0.15 to 1.5, still more preferably, 0.2 to 1. The method of
measurement of the melt viscosity .eta. is explained later in
detail, but it is a value measured at the same temperature as the
spinning temperature at a shear rate of 1216 sec.sup.-1.
[0115] In the polymer alloy type synthetic fiber, it is important
that the component A and the component B are uniformly blended, but
"uniformly blended" mentioned here means the following condition.
That is, when a cross-section slice of the synthetic fiber is
observed by a trans-mission electron microscope (TEM) (40,000
times), as shown in FIG. 1, it has a so-called sea/island structure
in which the continuous matrix component (black portion) is the sea
component, and the approximately circular and dispersed component
(white portion) is the island component and, further, it is in a
condition that a domain size of the component A constituting the
island component is as small as 0.001 to 2 .mu.m in diameter
equivalent (diameter of hypothetical circle equivalent to the
domain area). By making the domain size of the island component
into the above-mentioned range, it is possible to greatly improve
abrasion resistance of fiber. The exposed area ratio of aliphatic
polyester resin (A) in the polymer alloy type synthetic fiber can
be determined by observing the above-mentioned TEM images for the
entire peripheral to thereby respectively measure exposed length of
the white portion exposed on fiber surface (aliphatic polyester
resin) and entire peripheral length of fiber, and calculating a
ratio of the lengths.
[0116] Furthermore, an adhesion force with the component B
constituting the sea component is improved as the domain size
becomes small, since stress concentration is dispersed, but on the
other hand, when the domain size is a specified size or less,
initial abrasion resistance is apt to decrease. Accordingly, it is
preferable that the island domain size is 0.005 to 1.5 .mu.m, and
0.02 to 1.0 .mu.m is more preferable. To control a glossy texture
of the crimped yarn, it is preferable to further control the domain
size in a specified range. It becomes possible to raise an
appropriate light scattering inside the fiber and to exhibit a
glossy texture of a dewy and excellent aesthetic appearance by
covering the wavelength range of visible light (0.4 to 0.8 .mu.m)
to 1/5 wavelength thereof (0.08 to 0.16 .mu.m) by the domain size.
To exhibit a beautiful glossy texture, it is preferable that the
domain size is in the range of 0.08 to 0.8 .mu.m.
[0117] The above-mentioned domain size means, as mentioned later in
item G of Examples, a distribution of 80 domains when 100 domains
per 1 crimped yarn sample are measured and the largest 10 domain
sizes and the smallest 10 domain sizes are excluded.
[0118] Furthermore, in the case where a material constituting the
crimped yarn is the polymer alloy type synthetic fiber, different
from a block copolymer in which an aliphatic polyester block and a
polyamide block are present alternatively in 1 molecular chain, it
is important that the aliphatic polyester molecular chain
(component A) and the polyamide molecular chain (component B) are
present substantially independently. This difference of conditions
can be estimated by observing a melting point depression of the
thermoplastic polyamide resin of before and after the compounding,
that is, how the melting point based on the thermoplastic polyamide
resin in the polymer alloy lowered from the melting point of the
thermoplastic polyamide resin before the compounding. If the
melting point depression of the thermoplastic polyamide resin is
3.degree. C. or less, the aliphatic polyester and the polyamide
have hardly copolymerized (ester-amide interchange has hardly
occurred), and it is a polymer alloy condition in which the
aliphatic polyester molecular chain and the polyamide molecular
chain are present substantially independently. Since the fiber
surface layer is substantially occupied by the thermoplastic
polyamide resin which is the sea component, characteristics
inherently pertaining to the above-mentioned thermoplastic
polyamide resin are reflected to the fiber and the abrasion
resistance is greatly improved. Accordingly, it is preferable that
the melting point depression of the polyamide compounded is
2.degree. C. or less.
[0119] In the case where the material constituting the crimped yarn
is a polymer alloy type synthetic fiber, a sea/island structure is
formed in which the aliphatic polyester resin forms the island
component and the thermoplastic polyamide resin forms the sea
component. By controlling the domain size of the island component,
as well as the abrasion resistance is greatly improved, high
quality glossiness is also exhibited.
[0120] As above-mentioned, since aliphatic polyester and polyamide
usually hardly react (esteramide interchange hardly occurs),
adhesion force of interface of the above-mentioned 2 polymers is
not so high as it is. In such a circumstance, it is possible to
improve abrasion resistance by greatly increasing adhesion force of
the interface by further adding a compatibilizer (hereafter, may be
referred to as "component C"). The component C is not especially
limited as far as it increases the adhesion force of the interface
between the component A and the component B, but it is preferable
if it is a compound having two or more active hydrogen reactive
groups in a molecule, since the adhesion force of interface is
increased greatly. By carrying out a spinning in which the compound
having two or more active hydrogen reactive groups in a molecule is
added to the component A and/or the component B and melt blended,
since the compound reacts with any components of the component A
and the component B to form a cross-linked structure, a peeling off
of the interface can be prevented.
[0121] The active hydrogen reactive group is a group having a
reactivity with COOH terminal group, OH terminal group or NH.sub.2
terminal group present at the terminal of polylactic acid resin or
of the thermoplastic polyamide resin, for example glycidyl group,
oxazoline group, carbodiimide group, aziridine group, imide group,
isocyanate group, maleic acid anhydride group or the like are
preferably used. In the melt spinning which is the production
method of the crimped yarn, since molding is carried out at a
relatively low temperature as 250.degree. C. or less, a compound
excellent in low temperature reactivity is selected. Among the
above-mentioned reactive groups, glycidyl group, oxazoline group,
carbodiimide group or acid anhydride group (group produced from
maleic acid anhydride (may be referred to as maleic acid anhydride
group) or the like) are preferably used, and especially, glycidyl
group or carbodiimide group are preferably used. When 2 or more of
the above-mentioned reactive group are present, it can function as
a compatibilizer. On the other hand, when it has more than 20
reactive groups in a molecule, since spinnability may deteriorate
due to an excessive viscosity increase at the time of spinning, it
is preferable that the number of active hydrogen reactive groups in
a molecule is 2 or more and 20 or less. More preferably, it is 10
or less, still more preferably 3 or less. The kind of the reactive
group in one molecule may be plural. When the compound having 2 or
more of the above-mentioned active hydrogen reactive group is a
compound of which weight average molecular weight is 250 to 30,000,
it is preferable since it is excellent in heat resistance at melt
molding and dispersibility. More preferably, it is 250 to
20,000.
[0122] Furthermore, as a compound having these reactive groups, if
it is a copolymer graft copolymerized to the main chain of polymer
with a side chain having a reactive group, it is preferable since
not only it becomes possible to introduce many functional group in
a molecule, but also, in general, thermal characteristic such as
melting point becomes stable. Although it is possible to select a
polymer to be the main chain to be grafted with these reactive
groups, in view of easiness of its synthesis, it can be
appropriately selected from the group consisting such as of
polyester-based polymers, acrylate based polymers including
polyacrylate, polymethyl methacrylate or poly(alkyl)methacrylate,
polystyrene-based polymers and polyolefin-based polymers.
[0123] Among the component C which can be used, as the compound
having a glycidyl group, for example, a polymer of which monomer
unit is a compound having a glycidyl group or a compound of which
polymer to be the main chain is graft copolymerized with a glycidyl
group and, furthermore, those having a glycidyl group at terminal
of polyether unit are mentioned. As the monomer units having the
above-mentioned glycidyl group, glycidyl acrylate, glycidyl
methacrylate or the like are mentioned. Other than these units, it
is possible to control reactivity of glycidyl group by
copolymerizing such as a long chain alkyl acrylate. When an average
molecular weight of the polymer of which monomer unit is the
compound having a glycidyl group or the polymer to be the main
chain is in the range of 250 to 30,000, it is preferable since a
melt viscosity increase, when the component is added to be
contained in a high concentration, can be prevented. It is more
preferable that the weight average molecular weight is in the range
of 250 to 20,000. Other than that, a compound having 2 or more
glycidyl units on triazine ring is also preferable since its heat
resistance is high. For example, triglycidyl isocyanurate (TGIC),
monoallyl diglycidyl isocyanurate (MADGIC) or the like are
preferably used.
[0124] Furthermore, it is the same as to oxazoline group,
carbodiimide group, aziridine group, imide group, isocyanate group
and maleic acid anhydride group. Among the above-mentioned,
compounds having carbodiimide group is more preferable since they
are extremely excellent in low temperature reactivity. For example,
as examples of carbodiimide compounds, mono or dicarbodiimide
compounds such as diphenyl carbodiimide, di-cyclohexyl
carbodiimide, di-2,6-dimethyl phenyl carbodiimide, diisopropyl
carbodiimide, dioctyl decyl carbodiimide, di-o-toluoyl
carbodiimide, di-p-toluoyl carbodiimide, di-p-nitrophenyl
carbodiimide, di-p-aminophenyl carbodiimide, di-p-hydroxyphenyl
carbodiimide, di-p-chlorophenyl carbodiimide, di-o-chlorophenyl
carbodiimide, di-3,4-dichlorophenyl carbodiimide,
di-2,5-dichlorophenyl carbodiimide, p-phenylene-bis-o-toluoyl
carbodiimide, p-phenylene bis-dicyclohexyl carbodiimide,
p-phenylene bis-di-p-chlorophenyl carbodiimide,
2,6,2',6'-tetraisopropyl diphenyl carbodiimide, hexamethylene
bis-cyclohexyl carbodiimide, ethylene bis-diphenyl carbodiimide,
ethylene bis-di-cyclohexyl carbodiimide, N,N'-di-o-triyl
carbodiimide, N,N'-diphenyl carbodiimide, N,N'-dioctyl decyl
carbodiimide, N,N'-di-2,6-dimethyl phenyl carbodiimide,
N-triyl-N'-cyclohexyl carbodiimide, N,N'-di-2,6-diisopropyl phenyl
carbodiimide, N,N'-di-2,6-di-tert-butyl phenyl carbodiimide,
N-toluoyl-N'-phenyl carbodiimide, N,N'-di-p-nitrophenyl
carbodiimide, N,N'-di-p-aminophenyl carbodiimide,
N,N'-di-p-hydroxyphenyl carbodiimide, N,N'-di-cyclohexyl
carbodiimide, N,N'-di-p-toluoyl carbodiimide, N,N'-benzyl
carbodiimide, N-octadecyl-N'-phenyl carbodiimide,
N-benzyl-N'-phenyl carbodiimide, N-octadecyl-N-tolyl carbodiimide,
N-cyclohexyl N'-tolyl carbodiimide, N-phenyl-N'-tolyl carbodiimide,
N-benzyl N'-tolyl carbodiimide, N,N'-di-o-ethyl phenyl
carbodiimide, N,N'-di-p-ethyl phenyl carbodiimide,
N,N'-di-o-isopropyl phenyl carbodiimide, N,N'-di-p-isopropyl phenyl
carbodiimide, N,N'-di-o-isobutyl phenyl carbodiimide,
N,N'-di-p-isobutyl phenyl carbodiimide, N,N'-di-2,6-diethyl phenyl
carbodiimide, N,N'-di-2-ethyl 6-isopropyl phenyl carbodiimide,
N,N'-di-2-isobutyl 6-isopropyl phenyl carbodiimide,
N,N'-di-2,4,6-trimethyl phenyl carbodiimide,
N,N'-di-2,4,6-triisopropyl phenyl carbodiimide or
N,N'-di-2,4,6-triisobutyl phenyl carbodiimide, and
polycarbodiimides such as poly(1,6-hexamethylene carbodiimide),
poly(4,4'-methylene biscyclohexyl carbodiimide),
poly(1,3-cyclohexylene carbodiimide), poly(1,4-cyclohexylene
carbodiimide), poly(4,4'-diphenyl methane carbodiimide),
poly(3,3'-dimethyl 4,4'-diphenyl methane carbodiimide),
poly(naphthylene carbodiimide), poly(p-phenylene carbodiimide),
poly(m-phenylene carbodiimide), poly(tolyl carbodiimide),
poly(diisopropyl carbodiimide), poly(methyl-diisopropyl phenylene
carbodiimide), poly(triethyl phenylene carbodiimide) or
poly(triisopropyl phenylene carbodiimide) are mentioned. Among
them, polymers of N,N'-di-2,6-diisopropyl phenyl carbodiimide or
2,6,2',6'-tetraisopropyl di-phenyl carbodiimide are preferable.
[0125] Furthermore, the 2 or more active hydrogen reactive groups
may be the same or different reactive groups, but it is preferable
to be the same reactive group to control reactivity.
[0126] Furthermore, as the compound used as the component C, other
than the above-mentioned compounds having active hydrogen reactive
groups, polyalkylene ether glycols is preferable since it
peculiarly improve abrasion resistance. As the compounds, for
example, polyethylene glycol, polypropylene glycol, polybutylene
glycol or the like are mentioned, but among them, polyethylene
glycol of molecular weight 400 to 20,000 is preferable in view of
heat resistance, dispersibility and cost. More preferred is a
polyethylene glycol of molecular weight 600 to 6,000. It is more
preferable if both terminals of the compound were modified to
glycidyl group. It is also preferable to use it together with the
above-mentioned compound having 2 or more active hydrogen reactive
groups.
[0127] Furthermore, as a compound used as the component C, since it
is generally melt molded into a fiber at 200 to 250.degree. C. to
produce the synthetic fiber, a heat resistance durable thereto is
required. Accordingly, it is preferable that a heat loss ratio when
arrived at 200.degree. C. in a thermogravimetric (TG) analysis is
3% or less. When the heat loss ratio exceeds 3%, since pyrolyzates
bleed out at the time of spinning to thereby stain spinneret or
spinning machine, not only spinnability is deteriorated but also,
due to a smoke of gaseous pyrolyzate, a problem arises sometimes
that working environment may be aggravated. It is more preferable
that the heat loss ratio is 2% or less, still more preferably, it
is 1% or less. A 200.degree. C. heat loss ratio is the weight loss
ratio at 200.degree. C. when heated from a normal temperature (10
to 30.degree. C.) up to 300.degree. C. at a heating speed of
10.degree. C./min under nitrogen atmosphere in a thermogravimetric
(TG) analysis.
[0128] An amount of the component C to be added can be
appropriately determined by an equivalency per unit weight of
reactive group of the compound to be used, a dispersibility or
reactivity when melted, domain size of the island component and
blend ratio of the component A and the component B. To prevent
peeling of the interface, it is preferable to be 0.005 wt % or more
with respect to the total amount (100 wt %) of the component A, the
component B and the component C. More preferably, it is 0.02 wt %
or more, still more preferably, 0.1 wt % or more. When the amount
of the component C to be added is too small, its diffusion to and
degree of reaction between the interface of the 2 components are
not sufficient, and an increasing effect of adhesion force of the
interface may be limited. On the other hand, to exhibit the
performance of component C without impairing characteristics and
spinnability of the component A and the component B to be the base
material of the fiber, it is preferable that the amount of
component C is 5 wt % or less, and 3 wt % or less is more
preferable. Still more preferably, it is 1 wt % or less.
[0129] As the above-mentioned, by adding the component C, it is
possible to end-cap terminal carboxyl group of the aliphatic
polyester, and enhance hydrolysis resistance of the aliphatic
polyester. Concentration of the terminal carboxyl group having a
self-catalytic function is better to be low, and it is preferable
that the total carboxyl terminal group concentration in the
aliphatic polyester is 15 eq/ton or less, more preferably, 10
eq/ton or less and still more preferably, 0 to 7 eq/ton.
[0130] Furthermore, for the purpose of accelerating reaction of the
compound having the above-mentioned reactive group, it is
preferable to add a catalyst of a metal salt of carboxylic acid, in
particular, of its metal is an alkali metal or alkali earth metal,
to enhance reaction efficiency. Among them, it is preferable to use
a catalyst based on lactic acid such as sodium lactate, calcium
lactate or magnesium lactate. Other than that, for the purpose of
preventing a deterioration of heat resistance of the resin due to
the adding of a catalyst, it is possible to use a catalyst of which
molecular weight is relatively high such as stearic acid metal
salt, singly or in combination. The amount of the catalyst to be
added is, in view of controlling dispersibility and reactivity,
preferably, 5 to 2000 ppm with respect to the synthetic fiber. More
preferably, it is 10 to 1000 ppm and still more preferably, it is
20 to 500 ppm.
[0131] Furthermore, in the crimped yarn, it is preferable that at
least one kind crystal nucleating agent selected from talc,
sorbitol derivative, metal salt of phosphoric acid ester, basic
inorganic aluminum compound or salt of melamine compound is
contained. The crystal nucleating agents are crystal nucleating
agents effective mainly to the aliphatic polyester resin (A),
especially, to polylactic acid. By adding the crystal nucleating
agent, it becomes possible to obtain a crimped yarn of which crimp
resilience is hardly lost and excellent in fastness.
[0132] As the talc to be used as crystal nucleating agent, i.e., as
those exhibiting high crystallization characteristics while
maintaining mechanical characteristics of fiber, it is preferable
that an average particle diameter D.sub.50 is 5 .mu.m or less and
the amount of talc of which particle diameter is 10 .mu.m or more
is 0 to 4.5 vol % or less with respect to the total talc. By being
the average particle diameter D.sub.50 of the talc 5 .mu.m or less,
an effect as a crystal nucleating agent greatly increase due to
increase of apparent surface area. Accordingly, it is preferable
that the particle diameter of talc is 4 .mu.m or less and 3 .mu.m
or less is more preferable. Most preferred is 1.5 .mu.m or less.
The lower limit of the average particle diameter D.sub.50 of talc
is not especially limited, but if the particle diameter becomes
small, its aggregation is promoted to cause a poor dispersion in
the polymer and, accordingly, it is preferable to be 0.2 .mu.m or
more. It is preferable that the talc of particle diameter 10 .mu.m
or more is 4.5 vol % or less with respect to the total amount of
talc. When a coarse talc is contained, not only spinnability
decreases, but also mechanical characteristics of fiber may
deteriorate. Accordingly, a content of talc of which particle
diameter exceeds 10 .mu.m is more preferably 0 to 3 vol % with
respect to the total amount of the talc, still more preferably, it
is 0 to 2 vol % and most preferably, 0 vol %.
[0133] The particle diameter of talc described in the
above-mentioned items (1) and (2) is a value obtained from a
particle diameter distribution measured by a laser diffraction
method using SALD-2000J produced by Shimadzu Corp.
[0134] Furthermore, as the sorbitol derivatives preferably used as
the crystal nucleating agent, bisbenzylidene sorbitol, bis(p-methyl
benzylidene) sorbitol, bis (p-ethyl benzylidene) sorbitol, bis
(p-chlorobenzylidene) sorbitol, bis (p-bromobenzylidene) sorbitol,
and furthermore, sorbitol derivatives obtained by chemically
modifying the above-mentioned sorbitol derivatives are
mentioned.
[0135] Furthermore, as the metal salt of phosphoric acid esters or
as the basic inorganic aluminum compounds, compounds described in
JP2003-192883A are preferably used.
[0136] Furthermore, as the melamine compound, melamine, substituted
melamine compounds of which hydrogen of amino group is substituted
with an alkyl group, an alkenyl group or phenyl group
(JP-H9-143238A), substituted melamine compounds of which hydrogen
of amino group is substituted with a hydroxyalkyl group, a
hydroxyalkyl n (oxaalkyl) group or an aminoalkyl group
(JP-H5-202157A), deammonia condensates of melamine such as melam,
melem, mellon or methone, guanamines such as benzoguanamine or
acetoguanamine, can be used. As the salt of melamine compound,
organic acid salts or inorganic acid salts are mentioned. As the
organic acid salts, isocyanuric acid salt, carboxylic acid salts
such as of formic acid, acetic acid, oxalic acid, malonic acid,
lactic acid or citric acid, aromatic carboxylic acid salts such as
of benzoic acid, isophthalic acid or terephthalic acid, are
mentioned. It is possible to use these organic acid salts singly or
also as a mixture of 2 kinds or more of them. Among these organic
acid salts, melamine cyanurate is most preferable. As the melamine
cyanurate, those surface treated with a metal oxide sol such as
silica, alumina or antimony oxide (JP-H7-224049A), those surface
treated with polyvinyl alcohol or cellulose ethers (JP-H5-310716A)
or those surface treated with a nonionic surface active agent of
HLB 1 to 8 (JP-H6-157820A) can also be used. The mol ratio of the
melamine compound and the organic acid is not especially limited,
but it is preferable that a free melamine compound or an organic
acid which has not formed a salt is not contained in the salt
compound. A production method of the organic acid salt of melamine
compound is not especially limited, but in general, it can be
obtained as a crystalline powder, when a melamine compound and an
organic acid are mixed and reacted in water, and then filtered off
or distilled off the water and dried. As the inorganic acid salt, a
hydrochloride, a nitrate, a sulfate, a pyrosulfate, alkyl
sulfonates such as methane sulfonate or ethane sulfonate, alkyl
benzene sulfonates such as of p-toluene sulfonic acid or dodecyl
benzene sulfonic acid, a sulfamate, a phosphate, a pyrophosphate, a
polyphosphate, a phosphonate, a phenyl phosphonate, an alkyl
phosphonate, a phosphite, a borate or a tungstate, etc., are
mentioned. Among these inorganic acid salts, melamine
polyphosphate, melamine polyphosphate melam melem complex salt or
p-toluene sulfonate are preferable. The mol ratio of the melamine
compound and the inorganic acid is not especially limited, but it
is preferable that a free melamine compound or an inorganic acid
which has not formed a salt is not contained in the inorganic acid
salt compound. The production method of the inorganic acid salt of
melamine compound is not especially limited, but in general, it can
be obtained as a crystalline powder when a melamine compound and an
inorganic acid are mixed and reacted in water, and then filtered
off or distilled off the water and by dried. The production method
of pyrophosphate or polyphosphate is described, for example, in the
specifications of U.S. Pat. No. 3,920,796, JP-H10-81691A,
JP-H10-306081A, etc.
[0137] Since the adding amount of the crystal nucleating agent and
the mechanical characteristics of fiber are in an inverse
correlation, it is preferable that the adding amount is 0.01 to 2
wt % with respect to the aliphatic polyester (A). If the amount to
be added is 0.01 wt % or more, since the aliphatic polyester
crystallize promptly at the cooling step after leaving the air jet
stufffer machine, it is possible to obtain a crimped yarn excellent
in crimp fastness. By making the amount to be added 2 wt % or less,
a crimped yarn excellent in crimp fastness can be obtained while
preventing a decrease of mechanical characteristics. It is more
preferable that the amount to be added of the crystal nucleating
agent is 0.05 to 1.5 wt % and still more preferably, it is 0.2 to 1
wt %.
[0138] Furthermore, to the crimped yarn, it is preferable to add Cu
salt, K salt, Mn salt, Cr salt, tannin or the like to improve
fastness to light. In particular, CuI or KI is effective to enhance
fastness to light of the polyamide resin. The compound to be added
may be one kind, or two or more may be used together. The amount to
be added may be 0.001 to 0.5 wt % with respect to the thermoplastic
polyamide resin (B), more preferably, it is 0.005 to 0.2 wt %,
still more preferably, 0.01 to 0.1 wt %.
[0139] Furthermore, it is preferable that grooves extending along
the fiber axis direction are formed on fiber surface of the crimped
yarn. The grooves means concave lines present on the fiber surface
as shown in FIG. 2, and extend approximately in parallel along
fiber axis direction (direction of 10.degree. or less to fiber
axis). By these grooves, on the fiber surface, incident light in
the grooves is appropriately diffused and absorbed, and it becomes
possible to exhibit a dewy glossiness excellent in aesthetic
appearance. It is preferable that the width of grooves is, to
effectively raise the diffusion, 0.01 to 1 .mu.m, more preferably,
it is 0.05 to 0.9 .mu.m, and 0.08 to 0.8 .mu.m is still more
preferable. When the aspect ratio of the groove (longitudinal axis
length of groove/width of groove) is approximately in the range of
3 to 50, a good glossy texture is exhibited without impairing
abrasion resistance. The grooves can be grasped by observation by
an electron microscope (SEM). As to the width of the groove, in SEM
images, by a photograph usually magnified 5,000 times, or magnified
1,000 to 10,000 times as required, and by defining maximum width of
each groove as its width of groove, 10 widths of groove are
measured and its average value is taken as the width of groove of
the present invention. For the above-mentioned 10 grooves,
respective both ends of the grooves are connected by straight lines
and the respective length of the straight lines are taken as
longitudinal axis length of the groove, and aspect ratios of the
respective grooves were determined (refer to FIG. 3). It is
preferable to control the number of grooves to 1 to 500 grooves in
the range of 10 .mu.m.times.10 .mu.m in SEM image, since a good
glossiness is exhibited without impairing abrasion resistance. More
preferred is 3 to 40 grooves and still more preferred is 5 to 30
grooves.
[0140] Furthermore, it is preferable that strength of the crimped
yarn is, to maintain processsability or mechanical strength of
product, 1 cN/dtex or more, and 1.5 cN/dtex or more is more
preferable. Still more preferably, it is 2 cN/dtex or more and
especially preferably, 3 cN/dtex or more. An air stuffer crimped
yarn (hereafter, referred to as "BCF yarn") having such strength
can be produced by the melt spinning stretching bulking method
mentioned later. It is preferable that elongation at break is 15 to
70% since processability for making fiber product is good. More
preferably, it is 20 to 65%, still more preferably, 30 to 55%. It
is possible to produce a crimped yarn having such elongation by the
melt spinning.cndot.stretching.cndot.bulking method mentioned
later. At this time, in view of making a high performance crimped
yarn having an elongation at break of the above-mentioned range, it
may also be preferable to make the strength to 4 cN/dtex or
less.
[0141] Furthermore, it is preferable that a boiling water shrinkage
of the crimped yarn is 0 to 15%, since dimensional stability of
fiber and fiber product are good. More preferably, it is 0 to 12%,
still more preferably, 0 to 8%, most preferably, 0 to 3.5%.
[0142] Furthermore, in conventional polymer alloy fiber of an
aliphatic polyester and a polyamide, by an interface tension
between polymers, a swelling having a diameter of 1.5 to 10 times
of spinning hole diameter called as Barus effect occurs just
beneath the spinning hole at the time of melt spinning. For that
reason, a thick-and-thin is easy to occur at thinning and deforming
step in spinning, and a yarn break may occur, or a problem may
arise in qualities such as yarn unevenness. It was succeeded that
the fiber is stably formed by, as mentioned later, minimizing Barus
effect by kind of polymer, best design of melt viscosity, control
of linear discharge velocity from spinneret, optimization of
cooling condition just beneath spinneret and control of spinning
speed, and even when a swelling occurred by the Barus, as well as
by controlling an elongational flow region as close as possible to
the spinneret surface, and quick (shortening distance from
discharging to completion of thinning and deformation).
Accordingly, yarn unevenness along the fiber longitudinal direction
is also small. It is preferable that yarn unevenness (Uster
unevenness, U %, Normal value) of the crimped yarn is, for its
processability or for preventing dyeing unevenness after dyeing, 2%
or less and 1.5% or less is more preferable. Still more preferably,
it is 1% or less.
[0143] It is preferable that the crimped yarn is a "BCF yarn" (BCF:
bulked continuous filament) obtained by an air jet stuffer machine
mentioned later. BCF yarn means a filament having an irregular
entangled loop-like crimp configuration obtained by turbulent flow
effect of hot fluid (dry air, etc.), and its configuration is
explained in detail in the first chapter (pages 25 to 39) of
"Filament Processing Technical Manual (2.sup.nd Bde)" edited by The
Textile Machinery society of Japan. Examples of BCF yarn are
explained by photographs of fiber shape of FIG. 4 and FIG. 5. FIG.
4 is a photograph observed by placing one example of BCF yarn on a
black paper in multifilament state and FIG. 5 is a photograph of
the multifilament of FIG. 4 separated into single fibers and placed
on a black paper. As obvious from FIG. 4, loops of single fiber are
formed in random direction, and has a crimp configuration in which
2 or more of single fibers are entangled. As is obvious from FIG.
5, amplitude and periodicity of loop of single fiber is irregular.
As shown here, in the BCF yarn, single fibers are respectively
folded in loop state and amplitudes of the loop are irregular with
no periodicity and have a configuration in which the single fibers
are entangled with each other. It has not an excessively folded
portion and not only high in bulkiness compared to false twisted
yarns or the like, but also since it has a characteristic that the
residual torque is small, when the crimped yarn or a fiber product
in which the crimped yarn is used is abraded, external force is
easy to be dispersed to respective single fibers, and a deformation
by the external force is hardly occurred.
[0144] Regarding the crimped yarn, it is preferable that a crimp
elongation percentage after boiling water treatment is 3 to 30%,
more preferably it is 5 to 30%, still more preferably, 8 to 30% and
especially preferably, 12 to 30%. Measurement of the crimp
elongation percentage after boiling water treatment is carried out
as follows.
[0145] A crimped yarn unwound from a package (crimped yarn winding
drum or bobbin) left in an atmosphere of an environmental
temperature 25.+-.5.degree. C. and relative humidity 60.+-.10% for
20 hours or more, is immersed for 30 minutes in boiling water in a
state without a load. After the treatment, it is dried in the air
for one day and night (approximately 24 hours) under the
above-mentioned environment, and this is used as a sample of
crimped yarn after boiling water treatment. This sample is loaded
with an initial load of 1.8 mg/dtex, and after leaving for 30
seconds, a marking is made at sample length of 50 cm (L1). Next,
after leaving for 30 seconds from the time of loading a measuring
load of 90 mg/dtex instead of the initial load, sample length (L2)
is measured. From the following equation, crimp elongation
percentage after boiling water treatment (%) is determined:
Crimp elongation percentage (%)=[(L2-L1)/L1].times.100.
[0146] When a crimp elongation percentage after boiling water
treatment of such crimped yarn is lower than 3%, it may be
insufficient in crimp development, poor in bulkiness and, for
example, when it is made into a carpet or the like, it may become a
carped with no voluminous feeling. On the other hand, it is
impossible to produce a crimped yarn of which crimp elongation
percentage after boiling water treatment is 30% or more, and when
the crimp elongation percentage is tried to increase over 30%,
strength of crimped yarn may decrease significantly or it may cause
a crimp unevenness or a yarn thickness unevenness.
[0147] As to the crimped yarn, it is preferable that, in a
processing step for making a fabric structure such as dyeing or
bulking processing treatment or in a long term use after being made
into a product, crimp is hardly lost and product appearance is
maintained for a long term. Accordingly, it is preferable that a
crimp elongation percentage under a load of 2 mg/dtex after boiling
water treatment (hereafter, referred to as "elongation percentage
under load") which is an index of crimp fastness is 2% or more. The
elongation percentage under load is more preferably, 3% or more,
and still more preferably, 5% or more. There is especially no upper
limit, but by the technique, increasing to around 15% is the limit.
The elongation percentage under load can be measured by the method
described in Examples.
[0148] As to cross-sectional shape of the polymer alloy type
synthetic fiber constituting the crimped yarn, it can be freely
selected from circular cross-section, hollow cross-section,
multi-hollow cross-section, multi-lobal cross-sections such as
trilobal cross-section, flat cross-section, W type cross-section, X
type cross-section and other non-circular cross-sections, but to
enhance bulkiness of the crimped yarn to achieve a voluminous fiber
structure, non-circular cross-section of its non-circularity
(D1/D2) is 1.2 to 7 is preferable. The higher the non-circularity
of the non-circular cross-section fiber, the more voluminous fiber
structure can be made, but, on the other hand, when the
non-circularity is excessively high, flexural rigidity of fiber
increases, and there may be problems such that softness decreases,
splitting of fiber (fibrillation) occurs or a glaring glossiness is
appeared. Accordingly, it is preferable that the non-circularity is
in the range of 1.3 to 5.5, and more preferably, it is in the range
of 1.5 to 3.5.
[0149] The production method of a crimped yarn constituted by the
polymer alloy type synthetic fiber which is one preferable example
is not especially limited, but, for example, the following method
can be employed by using a direct spinning-stretching-crimp
processing machine shown in FIG. 6.
[0150] That is, in the above-mentioned combination of the aliphatic
polyester resin (A) and the thermoplastic polyamide resin (B), it
is preferable that, as well as making the blend ratio (wt %) of the
component A and the component B into the range of 5/95 to 55/45,
the ratio of melt viscosity (.eta.b/.eta.a) is controlled into the
range of 0.1 to 2. At this time, when the blend ratio of component
A is close to the lower limit of the above-mentioned blend ratio,
for example, in case where the ratio of component A is 5 to 15 wt
%, melt viscosity ratio should be increased as 0.8 to 2, but when
the blend ratio of component A is close to the upper limit, for
example, in case where the ratio of component A is 45 to 55 wt %,
the ratio of melt viscosity should be 0.1 to 0.3, that is, it is
necessary to lower the melt viscosity of the thermoplastic
polyamide resin (component B) to 1/10 to 3/10 of the aliphatic
polyester resin (component A). This is to make the configuration of
the crimped yarn constituted of the polymer alloy fiber into a
sea/island structure fiber in which the aliphatic polyester resin
(A) constitutes the island component. In the above-mentioned range,
when the ratio of component A is in the range of 15 to 45 wt %, it
is possible to make the aliphatic polyester into an island
component by making the ratio of melt viscosity to the range of 0.2
to 1. As the melt viscosity .eta. for calculating the
above-mentioned ratio of melt viscosity (.eta.b/.eta.a), a value
measured at the same temperature as its spinning temperature and at
a shear rate of 1216 sec.sup.-1 is used.
[0151] Next, in combination of the above-mentioned polymer
characteristics and blend ratio, the polymer alloy is made into a
fiber by once palletized by using such as a twin screw kneading
machine, or by kneading followed by a melt spinning. As to adding
timing of the compatibilizer (component C), it may be added at the
timing of kneading of the component A and the component B, and as
to its adding method, it may be mixed and kneaded at the same time
with the component A and the component B by supplying the
compatibilizer as it is to a kneading machine, or a master pellet
containing the component C in a high concentration is prepared
beforehand, and it may be supplied to a twin screw kneading machine
by blending with pellet of the component A and the component B. In
the case of preparing a master pellet beforehand, since it is
important to prevent a reaction of the compatibilizer, it is
preferable that the master pellet is prepared with the component A
of which molding temperature can be lowered. The reason for
suppressing the reaction of the compatibilizer as small as
possible, when the compatibilizer is a reactive type, is to
effectively prevent the reactive group reacts one-sidedly to one
component.
[0152] As to jacket temperature at the time of kneading in melt
extrusion, it is preferable to be carried out, based on melting
point of the thermoplastic polyamide (component B) (hereafter,
referred to as Tmb), at Tmb+3.degree. C. to Tmb+30.degree. C., and
it is preferable that shear rate is 300 to 9800 sec.sup.-1. By
making the jacket temperature and shear rate in these ranges, when
a fiber is obtained, as well as it becomes possible to achieve the
domain diameter, a colorless polymer alloy fiber is obtained. When
the jacket temperature exceeds this range or the shear rate exceeds
10000 sec.sup.-1 to cause a heat generation by the shear, due to a
coloring of polymer, applications of the obtained crimped yarn may
be limited.
[0153] Similarly, to maintain the above-mentioned sea/island
structure and to prevent coloring, it is preferable that the
spinning temperature is also as low as possible, i.e., it is
preferable to carry out spinning at Tmb+3.degree. C. to
Tmb+40.degree. C. More preferable spinning temperature is
Tmb+3.degree. C. to Tmb+30.degree. C., and still more preferably,
it is Tmb+3.degree. C. to Tmb+20.degree. C.
[0154] Furthermore, to prevent re-aggregation of island domain in
the spinning pack to control domain diameter, a high mesh filtering
layer (#100 to #200), a porous metal, a nonwoven fabric filter of
small filtering size (filtering size 5 to 30 .mu.m) or a blend
mixer in pack (static mixer or high mixer) may be built in. In
particular, it is extremely effective that the domain is
re-dispersed by a nonwoven fabric filter of filtering size 20 .mu.m
or less just before being discharged from spinneret, to control the
domain diameter.
[0155] Furthermore, polymer blend substance of aliphatic polyester
and polyamide is an incompatible combination, and the molten
polymer shows a strong behavior in elastic term, and swelling by
Barus effect may become large. Accordingly, it is preferable that a
linear discharge velocity at spinning hole of spinneret is, to
prevent yarn swelling by Barus effect and also to stably extend and
make fine to improve spinnability, 0.02 to 0.4 m/sec, 0.03 to 0.3
m/sec is more preferable and 0.04 to 0.2 m/sec is still more
preferable. It is also effective to enlarge depth of spinning hole
to prevent the Barus. Depth of spinning hole means the length from
the lower end of inlet hole to discharge surface as shown in FIG. 7
(a). In the case of a circular hole, depth of spinning hole means
the length from lower end of tapered portion to discharge surfaces
shown in FIG. 7 (b). The depth of spinning hole is preferably 0.3
to 5 mm, more preferably, it is 0.4 to 5 mm, and still more
preferably, 0.5 to 5 mm.
[0156] Furthermore, it is necessary that a discharged yarn has an
elongational flow region as close as possible to the spinneret
surface and quick (shortening distance from discharge to completion
of thinning and deformation). Accordingly, it is preferable that a
starting point of cooling of the discharged yarn is close to the
spinneret surface, i.e., it is preferable to start cooling from a
position substantially vertically beneath 0.01 to 0.15 m from the
spinneret surface. The starting point of cooling substantially
vertically beneath means, as shown in FIG. 8 of an enlarged
discharge portion, the intersection "c" of line "a" and line "b,"
when line "a" is drawn horizontally from the upper end of the
cooling air blow-off area and vertical line "b" is drawn downward
from the spinneret surface, i.e., it means that the distance "cd"
from the spinneret surface "d" to "c" on the vertical line "b" is
preferably 0.01 to 0.15 m. The starting point of cooling is more
preferably, from the spinneret surface substantially vertically
beneath 0.01 to 0.12 m, and still more preferably, from the
spinneret surface substantially vertically beneath 0.01 to 0.08
m.
[0157] Furthermore, the cooling method may be a uniflow type
chimney which cools from one direction, or may also be a circular
chimney which blows off cooling air from inside to outside of yarn
or from outside to inside of yarn, but a circular chimney which
cools from inside to outside of yarn is preferable, since a uniform
and quick cooling is possible. At this time, it is preferable to
cool multifilament by blowing off a gas substantially from a right
angle to the multifilament. A substantially right angle means that,
as shown in FIG. 8, flow line of the cooling air is substantially
perpendicular on line "b" (inclination is 70 to 110.degree.). As to
gas used as the cooling air is not especially limited, but a noble
gas which is stable at normal temperature (reactivity is extremely
low) such as argon, helium, nitrogen, or air are preferably used
and among them, nitrogen or air which are cheaply available are
especially preferably used.
[0158] Furthermore, at this time, it is preferable that a speed of
the cooling air is 0.3 to 1 m/sec, and 0.4 to 0.8 m/sec is more
preferable. It is preferable that a temperature of the cooling air
is low to cool the yarn quickly, but in relation to a cost of air
conditioning, 15 to 25.degree. C. is practical and preferable. As
above-mentioned, the sea/island structure is formed by a specific
combination of polymers and, further, the sea/island structure can
be discharged without a break by controlling spinning temperature
and, further, the polymer alloy fiber can be stably spun and taken
up for the first time by controlling the linear discharge velocity
at spinning hole of spinneret or, by controlling cooling method and
other conditions. The spun multifilament is covered with a known
finishing agent for spinning, but at this time, the amount of
deposition per yarn is, as a pure oil content, 0.3 to 3 wt % (in
case of oiling agent component: water or low viscosity mineral
oil=10:90, 3 to 30 wt % emulsion per yarn).
[0159] Furthermore, it is taken up at a spinning speed of 500 to
5000 m/min and wound, or continuously subjected to a stretching
bulking processing. However, when the polymer alloy type synthetic
fiber is left in an unstretched state, orientation relaxation is
likely to arise and when there is a time difference before the
stretching-bulking processing between unstretched yarn packages, an
unevenness of strength and elongation characteristics, heat
shrinking characteristics or crimp elongation percentage of fiber
easily occurs. Accordingly, it is preferable to employ a direct
spinning stretching bulking processing method in which spinning,
stretching and bulking processing is carried out in 1 step.
[0160] The stretching may be carried out in 1, 2 or 3 stages, but
in a case where a high strength of 2 cN/dtex or more is required,
it is preferable to stretch in 2 stages or more. FIG. 6 is a
schematic view of an apparatus for carrying out 2 stage stretching
crimp processing after spinning, but in this case, taking up at 500
to 5000 m/min in 1 FR, and simultaneously heating the 1 FR to
approximately 50 to 100.degree. C., carrying out first stage
stretching between the 1 FR (single hot roll) and 1 DR (tandem
roll), and successively carrying out 2.sup.nd stage stretching
between the 1 DR and 2 DR (tandem roll). At this time, it is
important that a stretching temperature (1 DR temperature of FIG.
6) for carrying out the 2.sup.nd stage stretching is higher than
the 1 FR by at least 20.degree. C. or more, to improve process
stability. Accordingly, in a case where 1 FR temperature is
adjusted to 50 to 100.degree. C., 1 DR temperature is adjusted to
the range of 70 to 130.degree. C. and in 1 FR temperature
+20.degree. C. or more. A stretching ratio of the 1 FR to the final
stretch roll (in the case of FIG. 6, 2 DR) may be controlled such
that the elongation at break of the stretched yarn sampled at the
exit of the final stretching roll becomes 15 to 65%, and
preferably, it is 20 to 60%. At this time, as methods for making
the elongation at break into the above-mentioned range,
automatically controlling the stretch ratio by recording beforehand
the relation between out put of polymer, spinning speed and stretch
ratio between respective rolls and the elongation at break of
stretched yarn sampled at exit of the final stretch roll by a PLC
(programmable controller), or a method of controlling the
elongation at break by, in the case where the elongation at break
of the stretched yarn, when the stretched yarn is sampled at the
exit of the final stretch roll, is lower than the above-mentioned
range, setting the stretch ratio low, or in the case where the
elongation at break is high, setting the stretch ratio high, to
thereby determine the stretch ratio by controlling such that the
elongation at break of the stretched yarn would be in the range of
15 to 65%, etc., are mentioned.
[0161] By setting to the above-mentioned stretching temperature and
stretch ratio, it becomes possible to obtain a stretched yarn of
which processing stability is high, and of a high strength and
small in yarn unevenness (Uster unevenness U %). Further, by heat
setting by setting the final stretch roll temperature at
Tma-30.degree. C. to Tma+30.degree. C. based on the melting point
of the aliphatic polyester resin (component A) (hereafter, referred
to as Tma), it becomes possible to obtain a stretched yarn of a
predetermined heat shrinkage ratio. By heat setting at such high
temperature, and further, by subjecting to a high temperature
bulking processing in the next step, it becomes possible to form
micro grooves on fiber surface of the crimped yarn. As a result, a
dewy glossiness excellent in aesthetic appearance can be imparted
to final product. For the bulking processing, an air jet stuffer
machine is used and the crimp processing is carried out at a nozzle
temperature of the machine higher than the final stretch roll
temperature by 5 to 100.degree. C.
[0162] As to the air jet stuffer machine, it is described in detail
in the first chapter (pages 25 to 39) of "Filament Processing
Technical Manual (2.sup.nd Bde)" edited by The Textile Machinery
society of Japan. That is, it is a crimp processing machine widely
used for production of crimped yarns for BCF carpet, and it is a
machine which imparts an irregularly entangled loop-like bulkiness
to a filament by using turbulent flow effect of air jet. As
examples of the machine, several embodiments of the machine are
described in FIGS. 116 to 130 of the above-mentioned Filament
Processing Technical Manual, and they can be appropriately selected
in consideration of fiber thickness of multifilament, fiber
thickness of constituting single filament, non-circular-ity,
rigidity, etc.
[0163] At this time, to lower the crimp elongation percentage after
boiling water treatment, the nozzle temperature should be low, and
to make the crimp elongation percentage high, the nozzle
temperature should be high. However, when the nozzle temperature is
set higher than Tmb, since processability deteriorates rapidly,
upper limit of the nozzle temperature is Tmb+10.degree. C. A hot
fluid introduced to the nozzle is not especially limited, e.g., dry
air, dry nitrogen, air contain-ing steam, etc., but hot air
containing steam is preferable in view of thermal efficiency and
running cost.
[0164] The yarn imparted with 3 dimensional crimp by an air jet
stuffer machine is successively cooled rapidly by being contacted
with a cooling drum, to thereby fix crimp structure. After that,
crimp uniformity is improved by loading an appropriate tension to
the crimped yarn, and wound into a package at a speed lower than
the peripheral speed of the final stretch roll by 10 to 30%. At
this time, relax ratio between the final stretch roll (in FIG. 6, 2
DR) and winder may be controlled such that the winding tension
would be in the range of 0.05 to 0.12 cN/dtex so that an excessive
tension would not be loaded to the crimped yarn, i.e., a yarn with
a high crimp elongation percentage is wound at a relax ratio of 20
to 30%, and a yarn of a low crimp elongation percentage is wound at
a relax ratio of 10 to 20%.
[0165] Next, regarding the "sheath/core type composite fiber of
which core component comprises the aliphatic polyester resin (A),
or the polymer alloy comprising the aliphatic polyester resin (A)
and the thermoplastic polyamide resin (B), and the sheath component
comprises the thermoplastic polyamide resin (B)" which is the
another preferable example is explained.
[0166] In the sheath/core type composite fiber, to prevent peeling
of the composite interface so that it can be applied to carpet uses
to which a strong external force is added repeatedly, it is
necessary to have a specified fiber structure.
[0167] As a result of our aggressive investigation on the peeling
phenomena of the sheath/core interface in the sheath/core type
composite fiber, we found that, to enhance peeling resistance of
the crimped yarn, degree of orientation of amorphous phases of the
respective core component and sheath component should be low and,
in addition, crystallinities in the respective core component and
sheath component should be high, that is, by having 2 phase
structure of the crystal phase and the unoriented amorphous phase
in the respective core component and the sheath component, the
peeling resistance is greatly improved. At first, as to the crimped
yarn, as a result of investigation of a factor for lowering the
peeling resistance, it was found that the molecular orientation of
the core component and the sheath component neighboring the
sheath/core interface is apt to increase compared to other region
than the interface. It was found that, by being the molecular
orientation of the respective components neighboring the
sheath/core interface high, the sheath/core interface is apt to
have a residual stress, and when an external force is added, it
triggers a growth of interface peeling while releasing the
stress.
[0168] It is not clear as to the factor why the molecular
orientation of the core component and the sheath component
neighboring the sheath/core interface of the sheath/core type
composite fiber becomes high compared to other region, but it is
estimated because, probably, when the respective core and sheath
components thermally shrink in the crimp processing, an undue force
is added to the sheath/core interface. That is, heat shrinkage of
the fiber is caused by releasing molecular orientation of amorphous
phases of the respective core component and sheath component, but
at this time, in case of a sheath/core type composite fiber of
which core component and sheath component are different components
with each other, both components have differences in heat shrinking
characteristics. By this difference of heat shrinking
characteristics, heat shrinkages of the respective components are
prevented or accelerated by the other component. It is estimated
that the molecular chains of the core component and the sheath
component neighboring the sheath/core interface are affected by an
undue stress at transmitting heat shrinkage to each component and,
as a result, their molecular orientations are not sufficiently
released to be left in an unstable condition. A residual stress is
generated in the sheath/core interface by a molecular movement that
such molecular chain of unstable orientation condition is
orientation relaxed. When an external force is added, it triggers a
growth of an interface peeling while the stress is released.
[0169] In crimped yarns such as a false twisted yarn or a
mechanically crimped yarn, molecular orientation of the
above-mentioned core component and sheath component neighboring the
sheath/core interface is apt to increase and a residual stress is
generated in the sheath/core interface and an interface peeling may
occur. On the other hand, it was found that in the case where a
multifilament comprising the sheath/core type composite fiber is
used as a BCF yarn, different from the above-mentioned other
processings, the generation of the residual stress of the
sheath/core interface is greatly prevented to become an internal
structure which hardly arise the interface peeling. It is not clear
as to the reason, but it is estimated that, in a crimp processing
by air jet stuffer, by the turbulent flow effect of hot fluid, the
core component and the sheath component of the respective single
fibers can be heated uniformly in a short time close to the melting
point of the thermoplastic polyamide resin (B) (Tmb), and
simultaneously heat shrank under no tension condition and, in
addition, by being cooled immediately and rapidly by a cooling
roll, even in the region neighboring the sheath/core interface, it
is possible to sufficiently release molecular orientation of the
amorphous phase, and the history based on the difference of heat
shrinking characteristics of the respective components is hardly
remained.
[0170] Furthermore, the residual stress of the sheath/core
interface is also stored when the molecular chain of the core
component and the sheath component neighboring the sheath/core
interface of which orientation condition is unstable is orientation
relaxed in later stage processing steps such as dyeing or in a
change with lapse of time when used as a product, in particular, in
case where the aliphatic polyester (A) is used as the core
component, not only in a case where it is exposed to heat, but also
by a change with lapse of time, the molecular orientation of the
amorphous phase is easy to be released. Accordingly, a residual
stress in the sheath/core interface is easy to generate and the
interface is easy to be peeled off. That is, the lower the
molecular orientation of the respective amorphous phases of the
core component and sheath component of the crimped yarn, the more
excellent the peeling resistance, and it is preferable. Further,
the more the crystal phases are present in the core component and
sheath component, the more the relaxation movement of the molecular
chain of the amorphous phase is bound to render the peeling
resistance excellent, and it is preferable.
[0171] The fiber structure of the crimped yarn is closely related
to physical properties of the crimped yarn, and the crimped yarn
comprising the sheath/core type composite fiber is achieved by
adjusting to a specified strength, boiling water shrinkage and
single fiber thickness.
[0172] Strength of the crimped yarn may become high as the degree
of orientation of amorphous phase inside the fiber becomes high. In
ordinary crimped yarn comprising single component, as the strength
becomes high, it is more preferable in view of processability and
durability when used as a product, but in the crimped yarn in which
the sheath/core type composite fiber is used, since the lower the
degree of orientation of amorphous phase, the more excellent in
peeling resistance, it is preferable that the strength is 3 cN/dtex
or less. By controlling the strength of crimped yarn to 3 cN/dtex
or less, the degree of orientation of amorphous phase inside the
fiber becomes sufficiently low and a residual stress in the
sheath/core interface hardly generates, it becomes a crimped yarn
excellent in peeling resistance, and it is preferable. It is
preferable that the strength is 2.8 cN/dtex or less since a crimped
yarn more excellent in peeling resistance is obtained, to be 2.6
cN/dtex or less is more preferable, and to be 2.4 cN/dtex or less
is still more preferable. On the other hand, when the strength is
too low, spinnability, processability of later stage processing
step and durability as a product may be poor. Accordingly, it is
necessary that the strength is 1.5 cN/dtex or more, to be 1.7
cN/dtex or more is preferable, to be 1.9 cN/dtex or more is more
preferable and to be 2.1 cN/dtex or more is still more preferable.
The strength can be measured by the way indicated in Examples.
[0173] By boiling water treatment, the molecular orientation of the
amorphous phase is released and the fiber shrinks. At this time,
crystal phases present in the fiber function as binding points and
prevent relaxation of the amorphous phase. That is, the boiling
water shrinkage of the crimped yarn (hereafter, referred to as
"boiling water shrinkage") becomes low as the degree of orientation
of amorphous phase inside the fiber becomes low and the
crystallinity becomes high. That is, in the crimped yarn, as the
boiling water shrinkage becomes low, the degree of orienta-tion of
amorphous phase inside the fiber becomes low and the crystallinity
becomes high, and a residual stress in the sheath/core interface
hardly generates and the peeling resistance becomes excellent and
it is preferable.
[0174] It is possible to measure the boiling water shrinkage by the
method shown in Examples, and can be calculated by measuring the
change of fiber length under tension free condition between before
and after boiling water treatment of the crimped yarn. It is
preferable that the boiling water shrinkage of the crimped yarn is
6% or less. It is more preferable that the boiling water shrinkage
is 5% or less since the crimped yarn becomes more excellent in
peeling resistance, to be 4% or less is still more preferable and
to be 3% or less is especially preferable. The lower the boiling
water shrinkage, the more preferable, and to be 0 to 2% is most
preferable. The boiling water shrinkage may be, ideally, 0%.
[0175] Furthermore, it is preferable that the sheath/core type
composite fiber has a single fiber thickness of 5 to 40 dtex. By
being the single fiber thickness 40 dtex or less, in the crimp
processing step, the fiber is heated quickly and inside the
cross-section of the single fiber is heated uniformly, an undue
stress is unlikely to arise in the molecular chain of the core
component and sheath component neighboring the sheath/core
interface and in the sheath/core interface, a residual stress is
hardly left. That is, it is excellent in peeling resistance.
Simultaneously, since a crystallization easily occurs, fiber
structure is fixed, and it is preferable since peeling resistance
can be maintained for a long term even after dyeing step or after a
change with lapse of time. To make the molecular orientation of
amorphous phase more low, and the crystallinity high, that is,
since peeling resistance of the crimped yarn becomes excellent, it
is preferabl that the single fiber thickness is as fine as
possible, to be 38 dtex or less is preferable, to be 35 dtex or
less is more preferable, to be 33 dtex or less is still more
preferable and to be 30 dtex or less is especially preferable. On
the other hand, however, when the single fiber thickness is
excessively fine, although it is easy to form 2 phase structure of
a crystal phase and a random amorphous phase in crimping treatment,
the crimped yarn is re-extended by a stretch tension added in later
crimp extending step, winding tension added in winding step of the
crimped yarn, or a tension added in later stage processing step, an
undue stress is easily generated in the sheath/core interface.
Accordingly, it is preferable that the single fiber thickness is 5
dtex or more. More preferably, it is 6 dtex or more and still more
preferably, 8 dtex or more. As above-mentioned, the problem of
peeling which was unavoidable in the crimped yarn constituted from
the sheath/core type composite fiber of which core component
comprises the aliphatic polyester resin (A) and the sheath
component comprises the thermoplastic polyamide resin (B), has been
overcome for the first time by controlling into strength: 1.5 to 3
cN/dtex, single fiber thickness: 5 to 40 dtex and boiling water
shrinkage: 6% or less.
[0176] In the sheath/core type composite fiber, the core component
comprises the aliphatic polyester resin (A) (hereafter, referred to
also as "component A"), or a polymer alloy comprising the aliphatic
polyester resin (A) and the thermoplastic polyamide resin (B)
(hereafter, referred to also as "component B"). It is preferable
that the above-mentioned 2 component constitutes 90 wt % or more of
the core component, and to be 93 wt % or more is more preferable
and to be 95 wt % or more is still more preferable.
[0177] In the sheath/core type composite fiber, it is preferable
that, by using the polymer alloy of the aliphatic polyester resin
(A) and the thermoplastic polyamide resin (B) as the core
component, and by forming so-called sea/island or sea/sea structure
in which the component A and the component B penetrate with each
other, peeling of the sheath/core interface between the sheath
component and the core component is prevented, and a fiber of which
abrasion resistance is sufficiently high is obtained. The component
B to be used as the core component and the component B to be used
as sheath component may be the same or different. Even if the
content of the component A of the sheath/core type composite fiber
is raised to 20 wt % or more, a fiber of which abrasion resistance
and heat resistance are high can be obtained.
[0178] It is preferable that the thermoplastic polyamide resin (B)
constituting the core component constitutes the sea. Further, to
raise the ratio of the aliphatic polyester resin (A) in the polymer
alloy of the core component, it is important that a melt viscosity
of the aliphatic polyester (A) at the time of melt spinning is made
higher than the thermoplastic polyamide (B).
[0179] It is preferable that a blend ratio (weight ratio) of the
component A and the component B which constitute the core component
of the sheath/core type composite fiber is, component A/component
B=95/5 to 20/80. By having the component B in the core component,
and by the presence of the component B at least in a portion of the
sheath/core interface, an adhesion force at the sheath/core
interface is improved to thereby prevent interface peeling, and it
is preferable. In the case of a sheath/core type composite fiber,
when a peeling arises at the sheath/core interface, the fiber
becomes easy to be fibrillated. Once a fibrillation starts,
abrasion speed of the fiber rapidly increases. Accordingly, to
enhance abrasion resistance of fiber, it is important to prevent
the peeling of the sheath/core interface. The more the component B
is contained in the core component, the easier to form the polymer
alloy structures (a) or (c) mentioned later which is considered to
be preferable, and it is preferable since abrasion resistance of
fiber becomes excellent. Accordingly, it is preferable that the
blend ratio of the component B in the core component is high. On
the other hand, however, for the sheath/core type composite fiber
to be a material also having an ability of reducing environmental
load, it is preferable that plant derived component A is contained
as much as possible, that is, it is preferable to lower the ratio
of the component B. To satisfy both requirements that adhesion
force of the sheath/core interface is increased to thereby render
the abrasion resistance excellent, and to be a material low in
environmental load, it is more preferable that component
A/component B is 80/20 to 25/75, to be 70/30 to 30/70 is still more
preferable and to be 60/40 to 35/65 is especially preferable.
[0180] As to the blend ratio (weight ratio) of component
A/component B of the core component, it can be calculated based on
the weight ratio of the component A and the component B to be
supplied to melt spinning. However, in case where the blend ratio
(weight ratio) of the compon-ent A and the component B at the
production is unclear, it can also be calculated by the following
equation, for convenience. That is, the core component of
sheath/core type composite fiber may contain the component A and
the component B and other small amount components, but in such
cases, it can be considered that the core component substantially
comprises the 2 compon-ents only of the component A and the
component B, and the blend ratio (weight ratio) of com-ponent
A/component B can be calculated. At first, sheath/core type
composite fiber cross-sec-tion slice is observed by a transmission
electron microscope (TEM) at a magnification of 40,000 times, and
total area (Aa) of the component A and total area (Ab) of the
component B constitute-ing the core component are determined. It
was calculated by the following equation by putting as the specific
gravity of component A 1.26, and as the specific gravity of
component B 1.14:
Component A/component B=(Aa.times.1.26)/(Ab.times.1.14).
[0181] Furthermore, in the cross-section, in a case where boundary
line of sheath component and core component in the cross-section
was difficult to decide, taking a similar figure in the
cross-section to the fiber cross-section circumscribing the
component A which is present at outermost layer and containing the
component A in its inside only as boundary line, sheath component
and core component was differentiated.
[0182] Furthermore, as the polymer alloy structure of the core
component in the single fiber cross-section, the following (a) to
(c) are mentioned, and any of these polymer alloy structures, by an
effect of interaction between the component B in the core component
and the component B in the sheath component, a good abrasion
resistance is exhibited. However, among them, since the component B
of the core component and the component B of the sheath component
forms a continuous phase and greatly improve the abrasion
resistance of fiber, it is preferable that the polymer alloy
structure of the core component is (a) or (c) and to be (a) is
especially preferable: [0183] (a) The component A is the island
component and the component B is the sea component (sea/island
structure) [0184] (b) The component B is the island component and
the component A is the sea component (sea/island structure) [0185]
(c) Both of the component A and the component B are sea component
(sea/sea structure).
[0186] The "sea/island structure in which the component A is the
island component and the component B is the sea component" which is
the preferable polymer alloy structure (a) constituting the core
component is explained with reference to the TEM photograph of FIG.
1. In FIG. 1, the dyed component is the thermoplastic polyamide
resin (B) and the undyed component is the aliphatic polyester resin
(A). As shown in FIG. 1, a structure in which the component A is
divided by the component B, which is a continuous region, into a
plural circular domains is defined as the sea/island structure of
(a) the component A is the island component and the component B is
the sea. So-called sea/island/lake structure in which the component
B is present inside the component A which is the island component
(approximately circular) is also included in the sea/island
structure. "Island-in-sea structure in which the component A is the
sea component and the component B is the island component" which is
the polymer alloy structure (b) is a structure in which the
component B is divided into a plurality of approximately circular
region by the component A which is a continuous region. "Sea/sea
structure in which both of the component A and the component B are
sea component" which is the polymer alloy structure (c) is defined
as a structure in which both of the component A and the component B
are not approximately circular, and the island component and the
sea component cannot be differentiated.
[0187] The polymer alloy structure of the core component closely
relates to the above-mentioned blend ratio (weight ratio) of the
component A and the component B or the viscosity ratio of melt
viscosity of the component A (.eta.a) and melt viscosity of the
component B (.eta.b) mentioned later, and by respectively
controlling to appropriate ranges, the alloy structure core
component can be controlled.
[0188] Furthermore, to obtain the structure (a) which is especially
preferable polymer alloy structure, it is preferable to make melt
viscosity of the component A .eta.a high and melt viscosity of the
component B .eta.b low. This is because the polymer alloy structure
is affected by the balance of melt viscosities of the component A
and the component B. The polymer alloy structure is formed by being
subjected to a shear deformation in a molten state, but a structure
of which shear stress generated by the shear deformation is
smallest is likely to be formed. This is because the energy level
of the whole system becomes low and stable. This means that sea
component to which the shear is added directly is likely to be
formed with a component of which melt viscosity is low, and on the
contrary, a component of which melt viscosity is high is likely to
constitute island component. That is, to make the structure (a)
which is an especially preferable polymer alloy structure, it is
preferable that the ratio of melt viscosity (.eta.b/.eta.a) is
small, and to be 2 or less is preferable, to be 1.5 or less is more
preferable and to be 1 or less is still more preferable. However,
when the ratio of melt viscosity becomes too small, since diameter
of the island component may become coarse and large, it is
preferable that the ratio of melt viscosity (.eta.b/.eta.a) is 0.10
or more, to be 0.15 or more is more preferable and to be 0.20 or
more is still more preferable. Details of measurement of melt
viscosity .eta. are mentioned later, but it means a melt viscosity
measured at a temperature of 240.degree. C. and at a shear rate of
1216 sec.sup.-1.
[0189] In the case where the core component of sheath/core type
composite fiber is a sea/island structure, it is preferable that
the diameter of island component is 0.001 to 2 .mu.m. It is
preferable since by making the upper limit of the Island component
diameter 2 .mu.m, interface area formed by the component A and the
component B greatly increases and fiber abrasion resistance greatly
increases. On the other hand, if the diameter of island component
is too small, the component A and the component B are
compatibilized in a molecular level to impair crystallinity, and
abrasion resistance, heat resistance and dyeing fastness of fiber
may deteriorate. In view of this point, it is preferable that the
lower limit of the island component diameter is 0.001 or more. From
this point, it is preferable that diameter of the island component
is 0.005 to 1 .mu.m and 0.01 to 0.8 .mu.m is more preferable. Still
more preferably it is 0.02 to 0.5 .mu.m.
[0190] The diameter of island component is, as explained in detail
in the Examples, a cross-section slice of the sheath/core type
composite fiber is observed by a transmission electron microscope
(TEM) (40,000 times), and for 100 islands per 1 sample of
sheath/core type composite fiber, diameters of island component
were measured (island was taken as a circle and diameter equivalent
to area of the hypothetical circle is defined as the island
component diameter). By adjusting diameter distribution of the
island component to the above-mentioned range, abrasion resistance,
heat resistance and dyeing fastness of the fiber are improved.
[0191] Furthermore, since a material constituting the core
component of sheath/core type composite fiber is a polymer alloy,
different from a block copolymer in which aliphatic polyester block
and polyamide block are present alternatively in 1 molecular chain,
it is important that the aliphatic polyester molecular chain
(component A) and the polyamide molecular chain (component B) are
present substantially independently.
[0192] This difference of conditions can be estimated by observing
a melting point depressions of the thermoplastic polyamide resin of
before and after the compounding, that is, how the melting point
based on the thermoplastic polyamide resin in the polymer alloy
decreased from the melting point of the thermoplastic polyamide
resin before the compounding. If the melting point depression of
the thermoplastic polyamide resin is 3.degree. C. or less, the
aliphatic polyester and the polyamide have hardly copolymerized
(ester-amide interchange has hardly occurred), and it is a polymer
alloy condition in which the aliphatic polyester molecular chain
and the polyamide molecular chain are present substantially
independently.
[0193] By being the component A and the component B are present
substantially independently in this way, the thermoplastic
polyamide resin (B) which forms the sheath component and the
thermoplastic polyamide resin (B) which forms the core component
easily arise an interaction to enhance adhesion force of the
interface of the sheath component and the core component, and it is
preferable. By this effect, characteristics which is inherent to
the thermoplastic polyamide resin (B), the sheath component,
reflects to fiber characteristics to greatly improve abrasion
resistance. For that reason, it is preferable that the melting
point depression of the thermoplastic polyamide (B) is 2.degree. C.
or less. Since adhesion force of the interface between the sheath
component and the core component increases, it is preferable that
the thermoplastic polyamide resin (B) used as the core component
and the thermoplastic polyamide resin (B) used as the sheath
component are polyamides of which main repeating unit is a same
kind of monomer. For example, it may be a combination of nylon 6
and a co polyamide of which main component is nylon 6 or a
combination of nylon 6 and nylon 610. Similarly, it is preferable
that the melting points of the 2 components are as close as
possible since, at the time of melt spinning, it becomes possible
to select a spinning temperature at which respective polymers
hardly decompose and the obtained fiber is excellent in abrasion
resistance. Accordingly, it is preferable that the melting point
difference of the thermoplastic polyamide resins used for the core
component and the sheath component, respectively, is 30.degree. C.
or less, to be 20.degree. C. or less is more preferable and to be
10.degree. C. or less is still more preferable.
[0194] Furthermore, it is preferable that the island component in
the polymer alloy of the core component is in a fine and long
streak-like configuration along the fiber axis. It is preferable
since, by being the Island component streak-like, a composite
interface area where one island component adheres to the sea
component becomes large and fibrillation can be prevented. There is
a merit that strength increases by forming the island component
fine and long streaks. It is most preferable that, in a case where
the Island component is streak-like, it is perfectly parallel to
fiber axis direction, but, those inclined 5.degree. or less from
fiber axis are defined as fine and long streak-like configuration
along fiber axis.
[0195] In the sheath/core type composite fiber, since as the
content of the component A (wt % of the component A with respect to
total fiber weight) increases, it becomes more environmental load
reducing material, it is preferable that the content of the
component A is high. It is preferable that the content of the
component A is 20 wt % or more, to be 30 wt % or more is more
preferable and to be 40 wt % or more is still more preferable. On
the other hand, in view of excellence in peeling resistance,
abrasion resistance or crimp fastness, it is preferable that the
content of component A is 80 wt % or less, to be 75 wt % or less is
more preferable and to be 70 wt % or less is still more preferable.
The content of component A (wt % of component A with respect to
total fiber weight) can be calculated by the method described in
Examples. That is, from difference between the fiber weight after
dissolving off the component A only from the crimped yarn
constituted from a sheath/core type composite fiber and the weight
of the original crimped yarn is taken as the weight of component A,
it is calculated by dividing the weight difference by the weight of
the original crimped yarn.
[0196] Furthermore, in case of the sheath/core type composite
fiber, it is necessary that the sheath component comprises the
thermoplastic polyamide resin (B) only. By having the thermoplastic
polyamide (B) as the sheath component, exposed area ratio of
aliphatic polyester resin (A) with respect to fiber surface area
becomes substantially zero, and abrasion resistance greatly
increases, and it is preferable. Since, by containing the component
B more in the sheath component, it becomes to a material more
excellent in abrasion resistance and heat resistance, it is
preferable that the component B constitutes 90 wt % or more of the
sheath component, to be 93 wt % or more is more preferable, to be
95 wt % or more is still more preferable.
[0197] The thermoplastic polyamide resin (B) may be, as
above-mentioned, a copolymer, but as more crystal phase is
contained in the sheath/core type composite fiber, an orientation
relaxation of amorphous phase can be prevented more in later stage
processing step or with lapse of time in product use, and it is
preferable since a residual stress is hardly generated in the
sheath/core interface and excellent in peeling resistance.
Accordingly, in the thermoplastic polyamide resin (B), since it is
preferable that the crystallinity is as high as possible, it is
preferable that a crystal melting peak calorie .DELTA.H is 10 J/g
or more, to be 20 J/g or more is more preferable and to be 30 J/g
or more is still more preferable.
[0198] Since the aliphatic polyester resin (A) and the
thermoplastic polyamide resin (B) hardly react, to enhance the
adhesion force of the sheath/core interface formed by the
above-mentioned 2 polymers, it is also preferable to add the
above-mentioned compatibilizer (component C). In particular, by
adding a compound having two or more active hydrogen reactive
groups in a molecule to the component A and/or component B and by
melt blending and carrying out spinning, the compound reacts with
any component of the component A and the component B to form a
cross-linked structure, and it is more preferable since peeling
phenomena of the sheath/core interface can be prevented.
[0199] Furthermore, as the melting points of the component B and
the component C becomes closer, at the time of melt spinning, it
becomes possible to select a spinning temperature at which
respective polymers more hardly thermally decompose, and it is
preferable since the obtained fiber is excellent in abrasion
resistance. Accordingly, it is preferable that the difference of
melting point between the component B and the component C is
30.degree. C. or less, to be 20.degree. C. or less is more
preferable and to be 10.degree. C. or less is still more
preferable.
[0200] The amount of the component C to be added can be
appropriately determined according to an equivalency per unit
weight of reactive group of a compound to be used, dispersibility
and reactivity at the time of melting or content of the component
A, but to prevent peeling of the sheath/core interface, it is
preferable to be 0.005 wt % or more with respect to the total
amount of component A, component B and component C. More
preferably, it is 0.02 wt % or more and still more preferably, 0.1
wt % or more. When the amount of the component C is too small, an
amount of reaction at the sheath/core interface is small, and the
effect of enhancing the adhesion force at the sheath/core interface
may be limited. On the other hand, to exhibit the performance of
component C without impairing characteristics and spinnability of
the component A and the component B to be the base materials of
fiber, it is preferable that the amount of component C is 5 wt % or
less and to be 3 wt % or less is more preferable. Still more
preferably, it is 1 wt % or less.
[0201] Furthermore, for the purpose of accelerating reaction of the
compound having the above-mentioned reactive group, it is
preferable to add a metal salt of carboxylic acid, especially, a
catalyst of which metal is alkali metal or alkali earth metal,
since it can enhance reaction efficiency. Among them, it is
preferable to use a lactic acid-based catalyst such as sodium
lactate, calcium lactate or magnesium lactate. Other than that, for
the purpose of preventing a lowering of heat resistance due to
addition of the catalyst, a catalyst of a relatively high molecular
weight such as stearic acid metal salt can be used singly or in
combination. It is preferable that an adding amount of the catalyst
is, for controlling dispersibility and reactivity, 5 to 2000 ppm
with respect to the synthetic fiber. More preferably, it is 10 to
1000 ppm, and still more preferably, 20 to 500 ppm.
[0202] In the sheath/core type composite fiber, it is preferable
that the sheath/core ratio (weight ratio) is 10/90 to 65/35.
However, as the ratio of core component becomes high, the area of
sheath/core interface increases and when the ratio of core
component is high, the component A, which is low in crystallinity
and easy to change with lapse of time, is contained in much amount,
a residual stress at the sheath/core interface is likely to arise,
and peeling resistance may deteriorate. Accordingly, to enhance
peeling resistance, it is preferable that an area of the
sheath/core interface per unit volume of the core component is
large, from this view point, it is preferable that the ratio of
core component is low. Furthermore, by increasing the ratio of
sheath component, there is a merit that crimp fastness is enhanced.
Accordingly, it is preferable that the sheath/core ratio is in the
above-mentioned range, to be 10/90 to 50/50 is more preferable and
to be 10/90 to 45/55 is still more preferable.
[0203] The sheath/core ratio can be calculated by, taking sum of
weight of the core component and the sheath component to be
supplied to melt spinning as 100, calculating respective ratios of
the core component and the sheath component with respect to the
sum. However, in the case where the weight ratio of the component A
and the component B at the time of production is unclear, it can
also be calculated by the following equation, for convenience. That
is, the core component of sheath/core type composite fiber may
contain the component A and other small amount components, and the
sheath component may contain the component B and other small amount
components, but even in such cases, it can be considered that the
core component substantially comprises the component A only, and
the sheath component comprises the component B only, and the
sheath/core ratio as weight ratio of the core component and the
sheath component can be calculated. At first, sheath/core type
composite fiber cross-section slice is observed by a transmission
electron microscope (TEM) at a magnification of 4,000 times, and
total area (Aa) of the component A and total area (Ab) of the
component B constituting the core component are determined. It was
calculated by the following equation by putting as the specific
gravity of component A 1.26, and as the specific gravity of
component B 1.14:
Sheath/core ratio=weight ratio core component/weight ratio of
sheath component
Weight ratio of core
component=[(Aa.times.1.26)/(Aa.times.1.26+Ab.times.1.14)].times.100
Weight ratio of sheath
component=[(Ab.times.1.14)/(Aa.times.1.26+Ab.times.1.14)].times.100.
[0204] As to cross-sectional shape of the sheath/core type
composite fiber, various cross-sectional shapes can be employed
such as circular type, Y type, multi-lobal type, polygonal type,
flat type or hollow type. In case of multifilament, respective
single fiber cross-sectional shapes may be the same or different.
One example of a single fiber cross-sectional shape of the
sheath/core type composite fiber is shown in FIG. 10. In FIG. 10,
respective 42s denote component A and 43s denote component B. In
FIG. 10, respective embodiments of circular type, Y type and
multi-global type are illustrated. As to the sheath/core type
composite fiber, it is preferable that the cross-sectional shape
is, in concrete, Y type, multi-lobal type or flat type, and Y type
or flat type is further preferable.
[0205] In the sheath/core type composite fiber, it is preferable
that the non-circularity (D3/D4) of single fiber is 1.3 to 4. As
the non-circularity of single fiber increases, fiber surface area
becomes large, and fiber is rapidly heated in crimp processing step
and inside the cross-section of fiber is heated uniformly and, an
undue stress is hardly added to molecular chain of the core
component and the sheath component neighboring the sheath/core
interface, and a fiber excellent in peeling resistance can be
obtained, so it is preferable. Accordingly, it is preferable that
the non-circularity of single fiber is 1.3 or more, to be 1.5 or
more is more preferable, to be 1.8 or more is still more preferable
and to be 2.0 or more is especially preferable. On the other hand,
however, when the non-circularity is excessively high,
cross-sectional shape may have an acute angle portion, and abrasion
resistance may deteriorate by an external force being concentrated
to the acute angle portion. There also is a problem in production
process that the core component becomes hard to be coated with the
sheath component uniformly in longitudinal direction. To solve
these problems, it is preferable that the non-circularity is 4 or
less, to be 3.8 or less is more preferable, to be 3.5 or less is
still more preferable and to be 3.3 or less is especially
preferable.
[0206] Regarding the non-circularity of single fiber, a single
fiber cross-section is observed by using TEM in the same method as
Examples, and it is defined as the ratio of diameter D3 of the
circumscribed circle and diameter D4 of the inscribed circle
(D3/D4) of the cross-section. When a non-circular cross-section is
considered to have an approximately line symmetry or point
symmetry, the inscribed circle is a circle inscribing to outlined
curve of the single fiber cross-section, and the circumscribed
circle is a circle circumscribing to outlined curve of the single
fiber cross-section. In case where a non-circular cross-section has
not a line symmetry or point symmetry at all, a circle inscribing
at least two points with outlined curve of the single fiber and
being present inside of the fiber only and having maximum radius
which does not intersect with the outlined curve of the single
fiber is defined as the inscribed circle. As to the circumscribed
circle, a circle circumscribing at least 2 points with outlined
curve of the single fiber, being present outside of the single
fiber cross-section only, and having minimum radius in the range
that circumference of the circumscribed circle and outline of the
single fiber does not intersect is defined as the circumscribed
circle. At calculating the non-circularity, non-circularity was
calculated for 10 cross-sections cut out from different portions
and averaged to determine.
[0207] In the sheath/core type composite fiber, it is preferable
that the non-circularity of core component (D1/D2) is 1.3 to 4. As
the non-circularity of core component increases, the sheath/core
interface area per unit volume of the core component becomes large,
and it is preferable since a fiber excellent in peeling resistance
is obtained. Accordingly, it is preferable that the non-circularity
of core component is 1.3 or more, to be 1.5 or more is more
preferable, to be 1.8 or more is still more preferable and to be 2
or more is especially preferable. On the other hand, when the
non-circularity of core component is excessively large, it becomes
difficult to uniformly coat with the sheath component in
cross-section or in longitudinal direction of the single fiber, and
peeling resistance may deteriorate. Accordingly, it is preferable
that the non-circularity of core component is 4 or less, to be 3.8
or less is more preferable, to be 3.5 or less is still more
preferable and to be 3.3 or less is especially preferable. The
non-circularity of core component is determined in the same way as
above-mentioned non-circularity of single fiber in which the
sheath/core composite interface is taken as the cross-sectional
shape.
[0208] Cross-sectional shapes of preferable crimped yarns are
exemplified in FIG. 10. Cross-sectional shape of core component of
the single fiber constituting the crimped yarn is optional, but it
is preferable that the cross-sectional shape of core component is
similar to the cross-sectional shape of single fiber in view of
enhancement of adhesion force of the sheath/core interface, and in
view of excellence of peeling resistance even when the core
component ratio of the crimped yarn and, further, even the content
of the component A is high. The similar shape does not mean a
mathematically precise similarity, for example, even a case where a
cross-sectional shape of single fiber is Y type and a
cross-sectional shape of core component is Y type and both
non-circularities are different, they should be understood as
similar shapes. As a matter of course, the sheath/core type
composite fiber is not limited to the cross-sectional shapes of
FIG. 10. The number of core component of sheath/core type composite
fibers is optional and a single fiber may have one core component
inside or may have a plural number of core components. The center
of gravity of outlined shape of single fiber cross-section and the
center of gravity of outlined shape of core component may be same
or different, but since as the fiber surface is covered more
uniformly with the sheath component, abrasion resistance becomes
more excellent, it is preferable that the center of gravity of the
outlined shape of single fiber and the center of gravity of the
outlined shape of core component is same. Outlined shapes of core
component of respective single fiber cross-sections in a
multifilament, may be same or different.
[0209] Furthermore, when the sheath/core type composite fiber is a
sheath/core type composite fiber of so-called sea/island type
composite fiber in which a plural core components is present in a
single fiber cross-section, it is preferable since sheath/core
interface area per unit volume of core component increases and
peeling resistance is improved. Accordingly, it is preferable that
the core component is 3 islands or more, to be 9 islands or more is
more preferable and 24 islands or more is still more
preferable.
[0210] In the sheath/core type composite fiber, in view of
excellence of abrasion resistance, it is preferable that the fiber
surface is substantially constituted of the sheath component
entirely in its longitudinal direction of the fiber, in particular,
it is preferable that the component A is not exposed on fiber
surface. In particular, in the sheath/core type composite fiber is
excellent in peeling resistance and, in addition, by being the
fiber surface substantially covered with the sheath component,
abrasion resistance is greatly improved. To enhance abrasion
resistance and peeling resistance, it is preferable that the sheath
component is thick in entire fiber cross-section, and it is
preferable that the minimum value of thickness of sheath component
is 0.4 .mu.m or more. To be 0.7 .mu.m or more is more preferable
and to be 1 .mu.m or more is still more preferable. In the case
where a polymer alloy as the core component in spinning step, there
is a merit in production that Barus effect can be prevented to
thereby raise processability. On the other hand, when the thickness
of the sheath is too thick, ratio of the aliphatic polyester resin
(A) with respect to the total fiber weight becomes low, and it may
be an outside of the purpose of providing a material for reducing
environmental load. Accordingly, it is preferable that thickness of
the sheath component is 10 .mu.m or less, to be 7 .mu.m or less is
more preferable and to be 5 .mu.m or less is still more preferable.
To thicken the minimum value of thickness of the sheath component,
it is preferable to control sheath/core ratio, single fiber
thickness and non-circularity of single fiber into the
above-mentioned range, and it is preferable to control melt
viscosity ratio of component A and component B and spinning
temperature into the range mentioned later.
[0211] In the sheath/core type composite fiber, as the
crystallinity increases, that is, as more crystal phases are
contained, the orientation relaxation movement of amorphous phase
of the core component and the sheath component can be prevented
more easily, and it is preferable since a crimped yarn excellent in
peeling resistance can be obtained. Furthermore, as the
crystallinity increases, abrasion resistance, heat resistance,
dyeing or crimp fastness, etc., become more excellent, and it is
preferable. The crystallinity can be evaluated by a total heat
capacity of melting peak of a differential calorimetric curve
measured at heating rate 16.degree. C./min, and it is preferable
that the total heat capacity of melting peak is 50 J/g or more,
more preferably, it is 60 J/g or more and still more preferably, 70
J/g or more. To exhibit such melting peak, it is necessary to use
high crystallinity polymers as the component A and the component B.
As mentioned later, to accelerate crystallization of respective
components, it is preferable to control production conditions such
as stretch ratio, heat treatment temperature after stretching, and
crimp nozzle temperature at crimp processing step.
[0212] In the sheath/core type composite fiber, since as the
bulkiness of the crimped yarn becomes more excellent, product
quality becomes more excellent, it is preferable that crimp
elongation percentage after boiling water treatment which is an
index of bulkiness of crimped yarn is high. Accordingly, it is
preferable that the crimp elongation percentage after boiling water
treatment is 5% or more, to be 10% or more is more preferable and
to be 15% or more is especially preferable. It is especially not
limited as to the upper limit of the crimp elongation percentage
after boiling water treatment, but when it is too high, single
fiber apt to be folded and peeling resistance may deteriorate. At
this point, it is preferable that the elongation percentage after
boiling water treatment is 35% or less, to be 33% or less is more
preferable and to be 30% or less is especially preferable.
[0213] In the sheath/core type composite fiber, in the dyeing step
or later stage processing step, or in a long term use after being
made into a fiber structure, it is preferable that crimp is hardly
lost (crimp fastness is high) and voluminous feeling of product can
be maintained for a long term. Accordingly, it is preferable that
the crimp elongation percentage after boiling water treatment under
a load of 2 mg/dtex which is an index of crimp fastness (hereafter,
crimp elongation percentage after boiling water treatment under a
load of 2 mg/dtex may be simply referred to as "elongation
percentage under load") is 2% or more. More preferably, it is 3% or
more, still more preferably, 5% or more and especially preferably,
7% or more. There is especially no upper limit, but for example, it
is preferable to be 30% or less to prevent adverse effects such as
dyeing unevenness (dark and light difference) at package terminal
surface portion at cheese dyeing processing due to an excessive
tightening of winding package. The elongation percentage under load
can be measured by the method indicated in Examples.
[0214] Furthermore, it is preferable that the elongation of the
sheath/core type composite fiber is 15 to 70%, since processability
for making into fiber product is good. A crimped yarn having such
elongation can be produced by adjusting stretch ratio into a
preferable range in the production method mentioned later. More
preferably, it is 20 to 60%, still more preferably, 30 to 50%.
[0215] It is preferable that a yarn unevenness of the sheath/core
type composite fiber is small. By reducing yarn unevenness, it
becomes possible to prevent a local concentration of an external
force when exposed to an abrasion, and it is preferable since
peeling resistance can be enhanced. Accordingly, it is preferable
that yarn unevenness (uster U %) (Normal) which is an index of yarn
unevenness is 2.5% or less, 2.0% or less is more preferable, 1.5 or
less is still more preferable and 1.0 or less is especially
preferable. Compared to conventional simple polymer alloy fiber of
an aliphatic polyester and a polyamide, in the sheath/core type
composite fiber, since it has a sheath component on fiber surface,
the Barus is prevented and thinning behavior is stabilized, yarn
unevenness is small and also has a merit to be excellent in
abrasion resistance. To reduce yarn unevenness, selecting component
A and component B of which melt viscosity ratio is in the
preferable range, and by stabilizing thinning behavior of spinline
or by carrying out melt spinning, stretching and crimping
continuously in 1 step, i.e., subjecting to a direct stretching,
crimping without allowing a change with lapse of time of the
unstretched yarn, etc., the yarn unevenness can be reduced.
[0216] A production method of the crimped yarn constituted by the
sheath/core type composite fiber which is one example is not
especially limited, but for example the following method can be
employed by using the direct spinning-stretching-crimp processing
machine shown in FIG. 9.
[0217] By raising melt viscosity (.eta.b) of the thermoplastic
polyamide resin (B) to be used, it becomes possible to raise fiber
temperature close to the melting point of the thermoplastic
polyamide resin (B) (Tmb) at heat treatment and crimp processing
step after stretching, without causing a fusion bond between single
fibers. By this, in the molecular chain of amorphous phase of the
thermoplastic polyamide resin (B), a polarization is progressed to
a molecular chain which is crystallized and to a molecular chain
which is orientation relaxed to random arrangement, and it is
preferable since peeling resistance becomes excellent. On the other
hand, to prevent sheath/core composite abnormality in spinning step
and in view of covering with the sheath component uniformly in
fiber cross-section and in fiber longitudinal direction, it is
preferable to suppress the melt viscosity of the thermoplastic
polyamide resin (B) (.eta.b) to an appropriate value. For the
above, it is preferable that the melt viscosity of the
thermoplastic polyamide resin (B) (.eta.b) is 10 to 300
Pasec.sup.-1, to be 20 to 250 Pasec.sup.-1 is more preferable and
to be 30 to 200 Pasec.sup.-1 is still more preferable.
[0218] In the case of a simple sheath/core type composite fiber of
the aliphatic polyester resin (A) and the thermoplastic polyamide
resin (B), by making uniform molecular orientation of the core
component and the sheath component in melt spinning step, the
respective components are uniformly stretched in later stretching
step, and at the time of crimp processing, a difference of heat
shrinking characteristics between the core component and the sheath
component hardly arises, and an undue stress is hardly added to
molecular chain neighboring the sheath/core interface and peeling
resistance is improved. Since molecular orientations of the core
component and the sheath component are controlled by stresses added
to the respective components in elongational deformation, it is
preferable that the melt viscosity of the aliphatic polyester resin
(A) (.eta.a) and the melt viscosity of the thermoplastic polyamide
resin (B) (.eta.b) are close, and it is preferable that the melt
viscosity ratio (.eta.b/.eta.a) which is the ratio of melt
viscosity of the component A and the component B is 0.2 to 2. More
preferably, it is 0.4 to 1.7, still more preferably, 0.6 to
1.4.
[0219] The melt viscosities .eta.a and .eta.b are melt viscosity
(Pasec) of the polymer used for the crimped yarn at temperature
240.degree. C. and shear rate 1216 sec.sup.-1, and they can be
measured by the method described in the Examples. In the case where
the component A and the component B used for the crimped yarn
cannot be obtained, they can be measured, for convenience, by
measuring relative viscosity (.eta.ra) of the component A in the
crimped yarn, and measuring relative viscosity (.eta.rb) of the
component B in the crimped yarn, .eta.a and .eta.b can be
determined for convenience. As indicated by plots of FIG. 11,
.eta.ra and .eta.a, .eta.rb and .eta.b are in the relation of the
following equations:
Relation between solution viscosity and melt viscosity of component
A log(.eta.a)=4.3049.times.log(.eta.ra)
Relation between solution viscosity and melt viscosity of component
B log(.eta.b)=5.2705.times.log (.eta.rb).
[0220] The relative viscosity can be measured by the method shown
in Examples. That is, by using an Ostwald viscometer, and for the
component A o-chlorophenol solution, and for the component B
sulfuric acid solution are used, and they are expressed by ratios
of drop time of solutions prepared by dissolving at specified
concentration, temperature and time respectively and solvents in
which respective components are not dissolved, and it is an index
indicating solution viscosity.
[0221] Furthermore, in the case where a polymer alloy prepared by
blending the aliphatic polyester (A) and the thermoplastic
polyamide resin (B) is used as the core component, while the
respective polymers being separately metered, they are mixed and
kneaded at melting point of the component B (Tmb) to melting point
of the component B (Tmb)+40.degree. C. by using a twin screw
extruding/kneading machine or single screw extruding/kneading
machine and once a polymer alloy resin is prepared. At this time,
it is preferable to use a twin screw extruding/kneading machine in
view of easiness of controlling diameter of island component. As a
method for controlling polymer alloy structure and diameter of
island component, it is possible to control by adjusting blend
ratio of the above-mentioned 2 components (component A and
component B) and melt viscosity ratio in the above-mentioned range,
and by kneading in the range of shear rate 200 to 20,000 sec.sup.-1
and residence time 0.5 to 30 min. In particular, as a method for
making the diameter of island component smaller, it is better that
the kneading temperature is low, the shear rate is high and the
residence time is short in the above-mentioned range. As the
polymer alloy resin which constitutes the core component of fiber
containing the component A and the component B, those prepared
beforehand by an extruding/kneading machine different from a
spinning machine may also be used after drying, or may be prepared
continuously at the time of spinning by an extruding/kneading
machine equipped to a spinning machine. In the case where it is
prepared beforehand, all polymer alloy to be used as the core
component may be a chip prepared beforehand, or a master chip in
which the component A or the component B is mixed/kneaded in a high
concentration is prepared and the master chip and the component A
and/or component B may be chip blended and used. Since it is easier
to uniformly disperse the component A and the component B, and it
is easier to prevent a thermal degradation of the component A, it
is also preferably employed to continuously prepare a polymer alloy
of the component A and the component B by a single screw kneading
machine and/or twin screw extruding/kneading machine equipped to a
spinning machine and supply it to a spinning pack.
[0222] By using the direct spinning.cndot.stretching.cndot.crimp
processing machine shown in FIG. 9, at joining and discharging in a
spinning hole of spinneret, the aliphatic polyester resin (A) or a
polymer alloy of the aliphatic polyester resin (A) and the
thermoplastic polyamide resin (B) as core component and the
thermoplastic polyamide resin (B) as sheath component, in a
sheath/core ratio (weight ratio) 65/35 to 10/90, by making a
combination of which melt viscosity ratio (.eta.b/.eta.a) is in the
range of 0.2 to 2 and setting spinning temperature to Tmb to
Tmb+30.degree. C. provided that the melting point of the
thermoplastic polyamide resin (B) is Tmb, a spun yarn is formed at
linear discharge velocity 1 to 20 m/min in the spinning hole of
spinneret. The spun yarn is cooled from vertically beneath 0.01 to
0.15 m from spinneret surface as starting point of cooling, by a
gas of wind speed 0.3 to 1 m/sec and wind temperature 15 to
25.degree. C. from the right angle to perpendicular direction on
spinneret surface to obtain a multifilament. The multifilament is
stretched in 2 stages in total stretching ratio 2 to 5 and then, at
being subjected to a crimp processing, heat set by setting first
stage stretching roll to 50 to 90.degree. C., the second stage
stretching roll to 90 to 150.degree. C. and final roll after the
stretching to 160 to 220.degree. C., and at being supplied to a air
jet stuffer crimp processing machine, subjected to a crimp
processing by setting nozzle temperature of the machine to a
temperature higher than the final roll temperature by 5 to
100.degree. C. to form a crimped yarn, taken up by contacting with
a cooling drum, and wound at a speed lower than the final roll
after stretching by 10 to 30%.
[0223] That is, aliphatic polyester resin (component A) such as
polylactic acid or polymer alloy (blend of component A and
component B) and the thermoplastic polyamide resin such as nylon 6
(component B) are respectively dried to prepare beforehand a
component A of which water content is 10 to 100 ppm and a component
B of which water content is 100 to 500 ppm. After the component A
and the component B are molten by separate twin screw
extruding/kneading machines or single screw extruding/kneading
machines, metered by separate gear pumps into a sheath/core ratio
(weight ratio) 65/35 to 10/90 and then, by assembling spinnerets as
shown in FIG. 12 as a spinneret constructed inside the spinning
pack, joined the component A and the component B and discharged to
obtain a spun yarn. In the case where a polymer alloy resin
comprising the above-mentioned the component A and the component B
as a core component, to prevent re-aggregation of the island
component (component A) in the polymer alloy, as filtering layer
for the core component, a device such as assembling a high mesh
filtering layer (#100 to #200) or porous metal, nonwoven fabric
filter of small filtering size (filtering size 5 to 30 .mu.m),
blend mixer in pack (static mixer or high mixer) is necessary. The
aliphatic polyester and the polyamide in the polymer alloy is an
incompatible combination, and since the molten polymer exhibits a
strong elastic behavior, a swelling called the Barus occurs and
thinning/deformation may become unstable. The polyamide (component
B) which is the sheath component has an effect of preventing the
Barus, and it is effective to control a melt viscosity of the
component B and a thickness of the sheath component into the
above-mentioned range. In addition, as methods for preventing the
Barus, raising spinning temperature to decrease tensile viscosity,
decreasing linear discharge velocity (polymer flow rate at final
tapered portion of spinning hole) by enlarging spinning hole
diameter of spinneret, Increasing length of L/D which is ratio of
spinning hole length and hole diameter, cooling spun yarn rapidly,
or the like are effective. FIG. 12 is a longitudinal-section
schematic view showing one example of a spinneret, and the
spinneret is constituted by an assembly of spinneret 2 (46) which
is a spinneret just before discharge and spinneret 1 (45) which
positioned just before spinneret 2 and has separate flow channels
for core component and sheath component.
[0224] When the component A and the component B are melted by a
kneading machine, it is preferable that the component A is melted
at a temperature of melting point of the component A (Tma) to
melting point of the component A (Tma)+40.degree. C., for example,
in case where the component A is polylactic acid of which melting
point is 170.degree. C., it is preferable to melt the component A
in the range of 170 to 210.degree. C. By melting the component A in
the above-mentioned range, hydrolysis of the component A of which
heat resistance is low can be prevented, viscosity unevenness of
the component A along longitudinal direction becomes hard to occur,
spinnability is improved and uniformity of the obtained fiber
becomes excellent, and therefore it is preferable. It is preferable
to melt the component B at a temperature of melting point of the
component B (Tmb) to melting point of the component B
(Tmb)+40.degree. C., for example, in the case where the component B
is nylon 6 of which melting point is 225.degree. C., it is
preferable to melt it in the range of 225 to 265.degree. C. By
melting the component B in the above-mentioned range, gelation or
coloring of the component B can be prevented, and therefore it is
preferable.
[0225] Spinning temperature can be determined by the melting point
of the component B (polyamide), and best range is melting point of
the component B Tmb to Tmb+30.degree. C. (for example, in the case
where melting point of the component B Tmb is 225.degree. C., it is
225 to 255.degree. C.). However, heat resistance of the component A
is not so high, if it exceeds 250.degree. C. when stored in molten
state, its physical properties may deteriorate rapidly.
Accordingly, as above-mentioned, it is preferable that a
thermoplastic polyamide resin (B) of which melting point is
250.degree. C. or less is selected as sheath component and setting
a spinning temperature to 260.degree. C. or less.
[0226] It is preferable that the linear discharge velocity at
spinning hole of spinneret is 1 to 20 m/min. By making the linear
discharge velocity 20 m/min or less, it becomes possible to
uniformly add shear stress in cross-section of single fiber to make
a uniform orientation of molecular chain of the core component and
the sheath component, and therefore, an undue stress is hardly
added to the sheath/core interface by heat shrinkage at a later
crimp processing, and a crimped yarn excellent in peeling
resistance can be obtained, and therefore, it is preferable. By
making linear discharge velocity 1 m/min or more, it is possible to
prevent a rapid thinning of spinline, and spinnability, or
uniformity of crimped yarn becomes better, and therefore, it is
preferable. It is more preferable to control linear discharge
velocity to 2 to 15 m/min and to control to 3 to 12 m/sec is still
more preferable. The linear discharge velocity, for the spinneret
just before polymer discharge 2 (46) in FIG. 12, is calculated by
the following equation based on spinning hole area, total output
and number of holes. When hole shape is different between holes of
spinneret, average of discharge area of all holes is calculated and
by employing an discharge area of a hole closest to the average
area, the linear discharge velocity is calculated by the following
equation.
[0227] FIG. 7 is a spinneret longitudinal-sectional view explaining
depth of spinning hole, hole diameter, slit length and slit width
and a schematic view of spinning hole, and slit length and slit
width of Y hole, multi-lobal hole and flat hole are shown in (a)
right drawing of non-circular hole and schematic view of spinning
hole.
linear discharge velocity (m/min)=Q/H/.rho./A/100 [0228] Q: Total
output (g/min) [0229] H: Number of holes [0230] .rho.: Melt density
(g/min) [0231] .rho.=1.08.times. content of the component A per
total fiber weight (wt %)/100+1.00.times.(1-content of the
component A per total fiber weight (wt %)/100) [0232] A: Discharge
area (cm.sup.2).
[0233] For example, in the case where spinneret hole shape is Y
hole (refer to FIG. 7 (a) non-circular hole), it can be calculated
by the equation, A (cm.sup.2)=3.times.slit width (cm).times.slit
length (cm)+(center triangle surrounded by slits), but in the case
where slit width is ignorably small compared to slit length, by
ignoring the area of (center triangle surrounded by slits), the
discharge area can be calculated by the equation, A
(cm.sup.2)=3.times.slit width (cm).times.slit length (cm).
[0234] Furthermore, it is preferable to make L/D, which is ratio of
hole diameter (D) and depth of spinning hole (L) of spinning hole
of spinneret, 0.6 to 10. By making L/D 10 or less, core component
is easily disposed to the center of fiber, and a crimped yarn
excellent in peeling resistance can be obtained, and therefore, it
is preferable. By making L/D 0.6 or more, the core component and
sheath component are uniformly distributed to respective holes and
sheath/core ratios become uniform between single fibers, i.e., all
fibers constituting multifilament are uniformly excellent in
peeling resistance, and therefore, it is preferable. It is more
preferable that L/D is 0.7 to 8, to be 0.8 to 6 is still more
preferable and to be 0.9 to 4 is especially preferable. The depth
of spinning hole means the depth of spinning hole in the spinneret
longitudinal-sectional view shown in FIG. 7, and it is the length
of which hole shape is maintained in the same shape as the spinning
hole, and it is a portion which controls flow rate when polymer is
extruded. In the case where a spinning hole is circular hole, the
hole diameter means the diameter of circular hole in the spinning
hole schematic view shown in FIG. 7. In the case where a spinning
hole is not a circular hole, discharge area A (cm.sup.2) is
calculated by the method described in the explanation of the linear
discharge velocity, and the diameter of hypothetical circle
equivalent to the discharge area is taken as the hole diameter.
[0235] When the component A and the component B are joined and
extruded by a spinneret, by controlling sheath/core ratio, melt
viscosity ratio of the component A and the component B, melt
viscosity of the component B and linear discharge velocity at
spinning hole of spinneret into the above-mentioned range, at
spinning and stretching steps, molecular orientation of the core
component and the sheath component becomes easy to be oriented, in
addition, it is possible to uniformly cover with the sheath
component along fiber longitudinal direction, and therefore, it is
preferable.
[0236] Furthermore, it is preferable to make vertically beneath
0.01 to 0.15 m from spinneret surface as starting point of cooling.
By making the starting point of cooling 0.15 m or less, spinline is
rapidly cooled, and the core component and the sheath component are
easy to be molecularly oriented, and therefore, it is preferable.
By making the starting point of cooling 0.01 m or more,
disadvantages such as discharge abnormality by containing an
unmelted polymer in spun yarn by spinneret surface being cooled
hardly occurs, and processability in production process is improved
and, therefore, it is preferable. Accordingly, it is more
preferable that the starting point of cooling is 0.02 to 0.13 m and
to be 0.03 to 0.12 m is still more preferable. A method of
positively heating spinneret surface is also preferable, by
arranging a ring heater around the spinneret surface so that the
temperature spinneret surface does not lower.
[0237] It is preferable that the cooling air is blown off to spun
yarn from a right angle to perpendicular direction on spinneret
surface, at wind speed 0.3 to 1 m/sec and wind temperature 15 to
25.degree. C. so that temperature of spinneret surface does not
lower.
[0238] Furthermore, when the fiber is left in a state of an
unstretched yarn or a stretched yarn, orientation relaxation is
likely to occur, and when there is a time difference between
unstretched yarn packages before stretching, or there is a time
difference between stretched yarn packages before crimp processing,
in particular, the molecular orientation of amorphous phase of the
core component, which is easy to be orientation relaxed, relaxes
earlier, and difference of heat shrinking characteristics of the
core component and the sheath component becomes large and, as a
result, a residual stress is easy to be generated at the
sheath/core interface of crimped yarn obtained by crimp processing.
Accordingly, it is preferable to employ a direct
spinning.cndot.stretching.cndot.crimp processing in which spinning,
stretching, crimping are carried out continuously in one step. That
is, it is preferable, after spun yarn is taken up by a take-up
roll, to carry out continuously, without winding, stretching and
heat treatment and then direct crimp processing.
[0239] An unstretched yarn is obtained by taking up a spun yarn,
and a stretched yarn obtained by stretching the unstretched yarn is
subjected to a crimping, but to enhance peeling resistance of the
sheath/core type composite fiber, it is important, at the crimping,
without generating an undue stress at the sheath/core interface, to
form a fiber structure polarized to a crystal phase and a random
amorphous phase. For that purpose, since it is preferable to highly
and uniformly orient the both component in stretched yarn before
subjecting to crimping, it is preferable to increase molecular
orientation of fiber at stretching step by subjecting stretching to
an unstretched yarn obtained at a low spinning speed. This is
because, when molecular chains of the core component and the sheath
component are oriented in a molten state by increasing spinning
speed, a difference is easy to arise in degree of orientation
between molecules of the respective components, i.e., it is
difficult to make molecular orientations of both component uniform.
In molten state, depending on melt viscosity ratio of the component
A and the component B, stresses added to respective components are
determined, and as spinning speed raises, that is, as spinning
tension of process increases, the stress difference added to
respective components becomes large. Accordingly, it is preferable
to lower spinning speed to make degree of orientations of core
component and sheath component of the unstretched yarn uniform.
Best spinning speed differs according to melt viscosity ratio of
component A and component B and sheath/core ratio, but making
spinning speed 3000 m/min or less, spinning tension can be kept
low, and it is possible to make degree of molecular orientation of
core component and sheath component in unstretched yarn uniform,
and therefore, it is preferable. On the other hand, by making
spinning speed 300 m/min or more, spinning tension becomes
moderately high, fiber oscillation of spinline is prevented to
stabilize thinning behavior, and therefore, it is preferable. It is
more preferable that the spinning speed is 350 to 2500 m/min, to be
400 to 2000 m/min is still more preferable and to be 450 to 1500
m/min is especially preferable.
[0240] Unstretched yarn of which molecular orientations of core
component and sheath component are low is molecularly oriented in a
later stretching step, but at this time, by carrying out stretching
stepwise in 2 stages or more, in addition, by raising stretching
temperature stepwise, it becomes possible to uniformly increase
molecular orientation of the core component and the sheath
component, and therefore, it is preferable.
[0241] It is very important to heat set at 160 to 220.degree. C. by
final roll after stretching. By raising heat set temperature to the
upper limit to enhance movability of molecular chain, it is
possible to polarize molecular chains of respective amorphous
phases of the aliphatic polyester (A) and the thermoplastic
polyamide resin (B) to a molecular chain to crystallize and to a
molecular chain to become random arrangement by orientation
relaxation, and therefore, it is preferable. Furthermore, since the
above-mentioned temperature range is around the melting point Tma
of the aliphatic polyester, a the core component partially melts on
the final roll, the stress at the sheath/core interface stored
until the heat set is released, and the obtained peeling resistance
of crimped yarn is greatly enhanced. More preferably, it is
170.degree. C. or more and still more preferably, 180.degree. C. or
more. On the other hand, by making the final roll temperature
220.degree. C. or less, a disadvantage that the sheath component
melts, single fiber cross-section deforms and the core component is
exposed to surface can be avoided, therefore, it is preferable.
More preferably, it is 210.degree. C. or less and still more
preferably, 200.degree. C. or less. After heat set by the final
roll in the above-mentioned range, it is immediately supplied
inside the nozzle, that is, by a residual heat effect, it is
possible to raise the fiber temperature in the crimp nozzle around
the melting point of the thermoplastic polyamide resin (B) (Tmb) in
a short time, and at the same time, it is possible to be subjected
to a heat shrink under no tension state, and as a result, a crimped
yarn of which both of the core component and the sheath component
have 2 phase structure of a crystal phase and a random amorphous
phase can be obtained, and by this way, for the first time,
generation of a stress at the sheath/core interface or a residual
stress can be prevented, and peeling resistance can be greatly
enhanced. To raise fiber temperature in the crimp nozzle, a method
of shortening the distance from the final roll to the crimp nozzle,
a method of keeping fiber temperature by a heat insulation box or a
method of heating by a noncontact heater are preferably
employed.
[0242] The final roll temperature is important for controlling
"crimp elongation percentage after boiling water treatment" which
is an index of bulkiness of the crimped yarn comprising the
sheath/core type composite fiber, or "elongation percentage under
load" which is an index of crimp fastness, and as the final roll
temperature is raised high, the crimp elongation percentage after
boiling water treatment and the elongation percentage under load
can be raised high. While aiming to obtain a crimped yarn excellent
in peeling resistance, to make a fiber having a strength of
necessary range, it is preferable to control total stretching
ratio, stretch roll temperature, final roll temperature after
stretching and temperature of crimp nozzle into the preferable
range, and at crimp processing, to sufficiently release the
molecular orientation of amorphous phase. To control the boiling
water shrinkage of the sheath/core type composite fiber into the
necessary range, it is preferable to control final roll temperature
after stretching and temperature of crimp nozzle into the
preferable range and then, after taking up by contacting around
cooling drum, to wind in a speed lower than that of the final roll
after stretching.
[0243] For example, in the case where the stretching is carried out
in 2 steps, it is preferable to heat set by setting first stage
stretching roll to 50 to 90.degree. C., the second stage stretching
roll to 90 to 150.degree. C. and final roll after stretching to 160
to 220.degree. C. More preferably, first stage stretch roll is set
to 60 to 80.degree. C., second stage stretch roll to 100 to
140.degree. C. and final roll after stretching to 170 to
210.degree. C.
[0244] Furthermore, in the case where the stretching is carried out
in 3 steps, it is preferable to set first stage stretching roll to
50 to 90.degree. C., second stage stretch roll to 90 to 130.degree.
C., third stage stretch roll to 130 to 160.degree. C. and final
roll after stretching to 160 to 220.degree. C. More preferably,
first stage stretch roll is set to 60 to 80.degree. C., second
stage stretch roll to 100 to 120.degree. C., third stage stretch
roll to 140 to 150.degree. C. and final roll after stretching to
170 to 210.degree. C.
[0245] By controlling total stretching ratio to 2 to 5 times, and
by appropriately increasing molecular orientation, it becomes
possible to immediately finalize heat shrinkage in the crimp
nozzle, and history of undue stress being added to the sheath/core
interface is hardly left, and therefore, it is preferable. As
above-mentioned, by stretching at an appropriate stretch ratio,
crystallization of the core component and the sheath component can
be accelerated, and a crimped yarn capable of maintaining peeling
resistance for more long term is obtained, in addition, crimp
fastness is also enhanced, and therefore, it is preferable. It is
more preferable that the total stretching ratio is 2.5 to 4.5 times
and to be 2.8 to 4.3 times is still more preferable. The total
stretching ratio is defined by the speed ratio of the first stage
stretch roll and the final roll after stretching, and it can be
calculated by the following equation:
Total stretching ratio=[speed (m/min) of final roll after
stretching]/[speed (m/min) of first stage stretch roll].
[0246] It is preferable that the stretched yarn heat set by the
final roll after stretching is imparted with a crimp by a nozzle in
an air jet stuffer crimp processing machine. As crimp processing
machines for forming a BCF yarn which is a preferable crimp
configuration, crimp imparting machines which carries out an
ordinary hot fluid processing treatment may be used, for example,
various crimp imparting methods such as a jet nozzle type, a jet
stuffer type and further a gear system are employed. To achieve a
high crimp imparting and its development, a jet nozzle system is
preferable, for example a crimp nozzle such as disclosed in the
specification of U.S. Pat. No. 3,781,949 is preferably used. To
enhance peeling resistance of the crimped yarn, it is preferable to
raise fiber temperature in the crimp nozzle, to immediately and
uniformly heat the core component and the sheath component of
respective single fibers to a high temperature state to be heat
shrunken, and it is preferable to raise the crimp nozzle
temperature higher than the final roll temperature after stretching
by 5 to 100.degree. C.
[0247] In the case where stretching step and crimp processing are
carried out in separate steps, it is extremely effective to subject
the stretched yarn to a heat treatment again by a hot roll or a hot
plate before supplying to the crimp nozzle. By carrying out heat
treatment again, it becomes easy to raise the fiber temperature in
the crimp nozzle and as above-mentioned, history of difference of
heat shrinkage characteristics of the core component and the sheath
component is hardly left at the sheath/core interface, and
therefore, it is preferable. It is preferable that the temperature
of re-heat treatment is 160 to 220.degree. C., to be 170 to
210.degree. C. is more preferable, and to be 180 to 200.degree. C.
is especially preferable.
[0248] Furthermore, after imparting crimp, by taking up while
contacting with a cooling drum, fiber structure of the crimped yarn
can be fixed to lower boiling water shrinkage, and therefore, it is
preferable. As the length contacting with the cooling drum of the
crimped yarn (contact length) becomes long, the fiber structure can
be fixed more and the fiber structure of the crimped yarn becomes
hard to change even a stress is added to the crimped yarn in later
winding step or in later processing step, and boiling water
shrinkage can be maintained low, and therefore, it is preferable.
It is preferable that the contact length is 20 cm or more, to be 30
cm or more is more preferable and to be 40 cm or more is still more
preferable.
[0249] It is preferable that, after taking up while contacting with
the cooling drum, the crimped yarn is wound in a speed lower than
that of the final roll after stretching without adding an excessive
stress to the crimped yarn. The temperature of the cooling drum is
usually 20 to 35.degree. C. At this time, in case where the winding
speed is lower than the final roll speed by 10 to 30%, by this, the
fiber structure fixed by the cooling drum is not changed again,
boiling water shrinkage can be kept low, a residual stress at the
sheath/core interface is hardly generated and a crimped yarn
excellent in peeling resistance can be obtained, and therefore, it
is preferable.
[0250] Furthermore, by stretching under an appropriate tension
between the cooling drum and the winder, maldistribution or
unevenness of crimp can be prevented, and uniformity can be
enhanced, and therefore, it is preferable. For example, 2 rolls are
placed between the cooling drum and the winder, and a method of
adding a tension by a speed difference between rolls, can be
employed. At this time, when the tension is excessively high, crimp
may be lost, accordingly, it is preferable that the tension for
stretch is 0.02 to 0.2 cN/dtex and to be 0.04 to 0.15 cN/dtex is
more preferable.
[0251] Furthermore, in an arbitrary step of before or after winding
the crimped yarn by the winder, it is preferable to subject the
crimped yarn to an interlacing treatment. The number and pressure
of the interlacing treatment may be controlled such that the CF
value of the crimped yarn would be 5 to 30, but since an interlace
imparted before the stretching step is loosened sometimes by the
stretching, it is preferable to interlace just before winding.
Since the yarn just before winding is under a low tension, it is
easy to be interlaced by a compressed air of a low pressure.
Accordingly, it is preferable since the crimped yarn is not
imparted with an undue stress, and peeling resistance can be
improved, and therefore, it is referable. It is preferable that the
compressed air for the treatment is 0.05 to 0.5 MPa. By subjecting
the crimped yarn to the interlacing treatment with an high speed
gas, a uniform heat treatment becomes easy and heat treatment can
be shortened.
[0252] On the other hand, it is possible to carry out crimp
processing by a false twist processing without limited to the air
jet stuffer crimp processing. In this case, by carrying out a
processing in which a highly relaxing treatment while being heated
after untwisting (Breria processing) is carried out, it is possible
to form 2 phase structure of a crystal phase and an unoriented
amorphous phase, and peeling resistance is easy to be enhanced, and
therefore, it is preferable.
[0253] Thus obtained crimped yarn can be used for fiber structure.
Further, the obtained crimped yarn can be processed by ordinary way
to a carpet to use as a carpet for a car interior.
[0254] Configuration of the crimped yarn may be a filament as it
is, or the obtained crimped yarn may be cut in an appropriate
length to handle as a staple.
[0255] In the case where the crimped yarn is a filament, it is
preferable to be interlaced and has a CF value in the range of 3 to
30. The CF value can be measured in the way described in the
Examples, and it is an index indicating a degree of being
interlaced. By making CF value 3 or more, unity of the crimped yarn
is enhanced, and it becomes possible to reduce friction between
single fibers, and at the time of fiber production, or later stage
processing or when used as a product, undue stress hardly
generates, and peeling resistance becomes excellent, and it is
preferable. It is more preferable that the CF value is 5 or more
and 7 or more is still more preferable. On the other hand, when CF
value is too high, single fibers are too much bound with each
other, crimp is bound (crimp elongation percentage after boiling
water treatment becomes low), or in bulking up step by heat (for
example, dyeing treatment, boiling water treatment or steam
treatment), crimp unevenness appears, etc., and for avoiding such
adverse effects, it is preferable that the CF value is 30 or less.
More preferably, it is 25 or less and still more preferably, 20 or
less.
[0256] Furthermore, there is especially no limit as to total fiber
thickness (fiber thickness as multifilament) of the crimped yarn,
but since residence time of the crimped yarn in the crimp nozzle
can easily be extended, it is preferable that the total fiber
thickness is 3000 dtex or less, to be 2500 dtex or less is more
preferable and to be 2000 dtex or less is still more preferable.
For making it easy to prevent pile fall when an external force is
added to carpet, it is preferable that the total fiber thickness is
500 dtex or more, to be 600 dtex or more is more preferable and to
be 700 dtex or more is still more preferable.
[0257] The number of single fibers (number of filaments)
constituting the crimped yarn can be freely selected.
[0258] Furthermore, in the case where the crimped yarn is used as a
fiber structure, it can be applied to a woven fabric, a knitted
fabric, a nonwoven fabric, a pile, cotton, etc., and other fibers
may be contained. For example, it may be a paralleled yarn, a
twisted yarn, a mixed yarn with a natural fiber, a regenerated
fiber, a semi-synthetic fiber or a synthetic fiber. As other
fibers, natural fibers such as cotton, linen, wool, silk or
regenerated fibers such as rayon or cupra, semi-synthetic fiber
such as acetate and synthetic fibers such as nylon, polyester
(polyethylene terephthalate, polybutylene terephthalate, etc.),
polyacrylonitrile and polyvinyl chloride can be applied.
[0259] Furthermore, as uses of the fiber structure in which the
crimped yarn is used, there are clothes in which abrasion
resistance is required, for example outdoor wear or sports wears
such as golf wear, athletic wear, ski wear, snow board wear and
pants thereof, casual wears such as boulzon, outers for
ladies/gentlemen such as coat, winter clothes and rain wear. As
uses which requires excellence in durability or moisture
degradation resistance in a long term use, a uniform, futons or
pillow such as kakefuton (a comforter) or shikifuton (futon
mattress), hadakakefuton (thin futon), kotatsu (wooden table frame
covered by a futon; underneath is a heat source) futon, zabuton
(cushion for sitting), baby comforter and blanket, sheets or
coverings of cushion or the like, mattress or bed pad, sheets for
hospital, medical care, hotel and baby or the like, and further,
bedding materials such as covering of sleeping-bag, cradle, baby
car, etc, and can also be preferably used in these applications.
Furthermore, it can also preferably be used for interior materials
of automobile, and among them, car carpet which require a high
abrasion resistance and moisture degradation resistance are the
best applications. It is not limited to these applications and it
may be used for, for example, anti-grass sheet for agriculture or
waterproof sheet for construction materials. As to car carpet which
is a use of preferable fiber structure, its processed structure is
not limited, for example, carpets having piles represented by woven
carpets such as dantsu, wilton, double face, Axminster, tufting,
embroidery carpet such as hook do rag, bonded carpets such as
bonded, electro-deposition or code, knit carpet such as knit or
raschel, compressed carpets such as needle punch, or combinations
thereof can be used. To obtain a carpet of low cost and voluminous
texture, a tufting carpet constituted of at least a front yarn
which is pile fiber, a base cloth to which the front yarn is tufted
and a backing material laminated to the base cloth is
preferable.
EXAMPLES
[0260] Hereafter, yarns, methods and fiber structures are explained
in detail with reference to examples. As methods of measurement in
the examples, the following methods were employed.
A. Weight Average Molecular Weight of Aliphatic Polyester
[0261] Tetrahydrofuran was mixed to a sample (aliphatic polyester
polymer) solution in chloroform to prepare a solution to be
measured. This was measured by gel permeation chromatography (GPC),
and determined weight average molecular weight in polystyrene
equivalent. In the case where a weight average molecular weight of
aliphatic polyester in a fiber was measured, a sample was dissolved
in chloroform, polyamide residue was removed by filtration, and
aliphatic polyester was taken out by drying the chloroform solution
to thereby provide it to a measurement.
TABLE-US-00001 GPC instrument: Waters2690 Column: Shodex GPC K-805L
(8 mm ID * 300 mm L), 2 columns were connected and used Solvent:
Chloroform (Wako, for HPLC) Temperature: 40.degree. C. Flow rate: 1
ml/min Concentration of sample: 10 mg/4 ml Filtration:
Maishori-disk 0.5.mu.-TOSOH Amount of injection: 200 .mu.l
Detector: Differential refractometer RI (Waters 2410) Standard:
Polystyrene (concentration: sample 0.15 mg/solvent 1 ml) Time for
measurement: 40 minutes
B. Amount of Residual Lactide in Polylactic Acid
[0262] Sample (polylactic acid polymer) 1 g was dissolved in
dichloromethane 20 ml and acetone 5 ml was added thereto.
Furthermore, it was precipitated by making to a constant volume
with cyclohexane, and analyzed by GC17A produced by Shimadzu, to
thereby determine an amount of lactide by an absolute calibration
curve. In the case of a polylactic acid in fiber, blend ratio of
polylactic acid and polyamide was determined beforehand by TEM
image which is mentioned later and amount of the above-mentioned
lactide was determined by correcting by the blend ratio.
C. Carboxyl Group Terminal Concentration
[0263] A precisely weighed sample (aliphatic polyester polymer
extracted by the following way) was dissolved in o-cresol (water
content 5%), and after an appropriate amount of dichloromethane was
added to this solution, it was determined by titrating with 0.02 N
KOH methanol solution. At this time, since oligomers such as
lactide which is cyclic dimer of lactic acid were hydrolyzed to
generate carboxylic group terminal, the total carboxyl group
terminal concentration including all of carboxyl group terminal
from polymer, carboxyl group terminal from monomer and carboxyl
group terminal from oligomer was determined. The method of
extracting aliphatic polyester from polymer alloy fiber (synthetic
fiber) or sheath/core type composite fiber is not especially
limited, but, by using chloroform, aliphatic polyester was
dissolved and filtered to remove polyamide, and then the filtrate
was dried to extract.
D. Sulfuric Acid Relative Viscosity and Inherent Viscosity of the
Thermoplastic Polyamide
[0264] Relative viscosity of nylon 6 was measured at 25.degree. C.
by preparing 0.01 g/mL solution in 98% sulfuric acid. Inherent
viscosity of nylon 11 was measured at 20.degree. C. by preparing
0.5 wt % solution in m-crezol.
E. Relative Viscosity of Aliphatic Polyester
[0265] Relative viscosity of aliphatic polyester was measured at
25.degree. C. by preparing 0.01 g/mL solution in
o-chlorophenol.
F. Melting Point and Heat of Crystal Fusion of Polymer
[0266] By using a differential scanning type calorimeter, DSC-7
model, produced by Perkin Elmer Inc., the temperature showing an
extreme value in endothermic curve of fusion measured by heating a
sample 20 mg at a heating rate of 10.degree. C./min was taken as
the melting point (.degree. C.). In addition, from the area
surrounded by the peak which forms the extreme value and the base
line (crystal melting peak area), heat of crystal fusion .DELTA.H
(J/g) of polymer was determined.
[0267] Furthermore, in the case where a raw material polymer cannot
be obtained, based on differential calorimetric curve of fiber, the
melting point of original polymer is decided. To which component a
melting peak of differential calorimetric curve of fiber is
pertained is decided by the following way. First, a crimped yarn
(fiber 1: crimped yarn containing the component A and the component
B) was subjected, as sample, to a DSC measurement in the same
measurement condition as above described, to obtain a differential
calorimetric curve 1. Next, the component A in sheath/core type
composite fiber (fiber 1) is removed by solvent (chloroform),
washed with water and vacuum dried for 24 hours at room
temperature. For the obtained fiber (fiber 2: fiber containing the
component B), a DSC measurement was carried out in the same
condition as above mentioned to obtain a differential calorimetric
curve 2. By comparing the differential calorimetric curves 1 and 2,
and by deciding that the disappeared melting peak is the melting
peak of the component A, the melting points were determined by
differential calorimetric curve 1.
[0268] Next, the component B in sheath component in sheath/core
type composite fiber (fiber 1) was removed by solvent (solution in
sulfuric acid), washed with water and vacuum dried for 24 hours at
room temperature. For the obtained fiber (fiber 3: fiber containing
the component A and the component B), a DSC measurement was carried
out in the same condition as above-mentioned to obtain a
differential calorimetric curve 3. By comparing the differential
calorimetric curves 1, 2 and 3, the melting point of the component
B in sheath component was decided. At this time, to obtain the
fiber 3, a solvent treatment condition (solvent temperature and
immersing time) by which only the component B in the sheath
component was substantially removed was decided beforehand. That
is, sheath/core type composite fiber was immersed in solvent
(solution in sulfuric acid) of a specified temperature for a
specified time, and then taken out, and the obtained fiber was
washed with water and vacuum dried for 24 hours at room
temperature. For this fiber, fiber surface is observed by an
optical microscope, and confirmed whether the sheath component is
removed or not. The above-mentioned operations are repeated for
plural solvent treatment conditions (solvent temperature and
immersing time), and a solvent treatment condition by which only
the component B of the sheath component is substantially removed,
was decided.
G. Total Heat Capacity of Melting Peak in Differential Calorimetric
Curve of Crimped Yarn
[0269] For sheath/core type composite fiber as a sample,
differential calorimetric curve was obtained in the same condition
as item F. Peaks which show extreme values in endothermic side
which are present in the differential calorimetric curve are
decided as melting peaks, and heat capacities obtained from the
areas of the respective melting peaks were totalized and it was
taken as the total heat capacity.
H. Melt Viscosity .eta.
[0270] By using Capirograph 1B produced by Toyo Seiki Co., and,
under nitrogen atmosphere, setting measurement temperature to the
same temperature as spinning temperature, respective melt
viscosities of the aliphatic polyester resin and the thermoplastic
polyamide resin at shear rate 1216 sec.sup.-1 were measured. The
measurements were carried out three times and their average value
was taken as the melt viscosity. It was measured, in case of
sheath/core type composite fiber and for a resin of which melting
point is 240.degree. C. or less, at 240.degree. C., and in case of
a resin of which melting point is 240.degree. C. or more, at
melting point +20.degree. C.
I. Exposed Area Ratio of Aliphatic Polyester Resin with Respect to
Fiber Surface Area of Crimped Yarn and Size of Island Domain and
Blend Ratio
[0271] One single fiber constituting a crimped yarn is taken out,
and an ultrathin section was cut out in a direction perpendicular
to fiber axis (fiber cross-section direction), polyamide component
of the cross-section is metal-dyed with phosphotungstic acid, and
by a transmission electron microscope (TEM) of a magnification of
40,000 times, blend state of all over the outer surface was
observed and taken into a photograph. From this image taken, fiber
peripheral length is measured, and further, all exposed lengths of
white portions (aliphatic polyester resin) exposed on fiber surface
are measured, and exposed area ratio of aliphatic polyester resin
was obtained from the total exposed length of the white portions
with respect to the fiber periphral length. Further, by using image
analyzing software, "WinROOF," of Mitani Corp., as to the TEM
image, provided that an island domain (undyed portion) as a circle,
a diameter (equivalent to diameter) (2r) calculated from the domain
area was taken as its domain size. The number of domains to be
measured is 100, and 80 domains, excluding 10 domains of largest
domain size and 10 domains of smallest domain size, were provided
to determine the distribution.
[0272] The blend ratio of the component A and the component B in
fiber was determined as weight ratio by correcting the
cross-sectional areal ratio obtained from the above-mentioned TEM
image (5.93.times.4.65 .mu.m) by specific gravities of the
respective components. The specific gravities of the respective
components are, polylactic acid: 1.24, nylon 6: 1.14, nylon 11:
1.04, nylon 610:1.08 and nylon 6/66 copolymer: 1.14. [0273] TEM
instrument: H-7100FA model produced by Hitachi, Ltd. [0274]
Condition: Acceleration voltage 100 kV.
J. Surface Configuration of Crimped Yarn
[0275] One single fiber constituting crimped yarn was taken out,
and its fiber surface condition was observed and taken into a
photograph by electron microscope ESEM-2700 produced by Nikon
Instech Co., at a magnification of 5,000 times, and from this image
taken, by using an image analyzing software "WinROOF" of Mitani
Corp., arbitrarily selected 10 widths of groove (maximum width)
were measured and its average value was taken as the width of
grooves. In addition, respective lengths of the groove were
measured and the aspect ratio (length of groove/width of groove)
was determined. As number of grooves, grooves present in
arbitrarily selected 10 .mu.m.times.10 .mu.m were counted.
K. Heat Loss Ratio of Compatibilizer
[0276] By using TG/DTA 6200 of EXSTAR 6000 series produced by Seiko
Instrument Inc., sample (component C) approximately 10 mg was
weighed by a balance and from its heat loss curve obtained at
heating rate 10.degree. C./min, the heat loss ratio at
200.+-.0.5.degree. C. was determined.
L. Sheath/Core Ratio
[0277] At providing to a melt spinning, a weight of core component
(comprises only the component A) and a weight of sheath component
(comprises only the component B) were weighed respectively and,
provided that total weight of the core component and the sheath
component was 100, respective weights of the core component and the
sheath component thereto were calculated.
[0278] In the case where the weight ratios when produced of the
core component and the sheath component are not known, it is
possible to calculate by the following equation for convenience.
That is, core component of the crimped yarn may contain the
component A and a small amount of other component, and sheath
component may contain the component B and a small amount of other
component, but even in such a case, it is possible to consider that
the core component substantially comprises the component A only and
the sheath component substantially comprises the component B only,
and it is possible to calculate the sheath/core ratio as the weight
ratio of the core component and the sheath component.
[0279] At first, a cross-sectional slice of crimped fiber was
prepared, polyamide component of the slice was metal dyed with
phosphotungstic acid, and the cross-sectional area of the crimped
fiber was observed by a transmission electron microscope (TEM) at a
magnification of 4,000 times and a photograph was taken. At this
time, sheath/core interface was decided by considering the undyed
region as the component A and the dyed region as the component B,
and by image analyzing by the image analyzing software, "WinROOF"
of Mitani Corp, total area of the region constituting the core
component (Aa) and total area of the region constituting the sheath
component (Ab) were determined. By considering the specific gravity
of the component A as 1.26, and the specific gravity of the
component B as 1.14, it was calculated by the following
equation:
Sheath/core ratio=weight ratio of core component/weight ratio of
sheath component
Weight ratio of core
component=[(Aa.times.1.26)/(Aa.times.1.26+Ab.times.1.14)].times.100
Weight ratio of sheath
component=[(Ab.times.1.14)/(Aa.times.1.26+Ab.times.1.14)].times.100
[0280] TEM instrument: H-7100FA model produced by Hitachi, Ltd.
[0281] Condition: accelerating voltage 100 kV
M. Identification of Core Component (Polymer Alloy) Structure in
Sheath/Core Type Composite Fiber
[0282] An ultrathin section was cut out from a direction
perpendicular to fiber axis of a sheath/core type composite fiber,
polyamide component of the section was metal dyed with
phosphotungstic acid and its polymer alloy structure was observed
and taken as a photograph by a transmission electron microscope
(TEM) at a magnification of 40,000 times. At this time, a case in
which the island component is not dyed was identified as polymer
alloy structure (a) and a case in which the island component was
dyed was identified as polymer alloy structure (b), and a case in
which island component and sea component could not be
differentiated (respective components were not approximately
circular, and island and sea could not be differentiated) was
identified as polymer alloy structure (c). [0283] TEM instrument:
H-7100FA model of Hitachi, Ltd. [0284] Condition: Acceleration
voltage 100 kV.
N. Measurement of Island Component Diameter of Core Component
(Polymer Alloy) of Sheath/Core Type Composite Fiber
[0285] In the item M, in cases where the polymer alloy structure
was identified as (a) or (b), by using an image taken in the same
way and by using the image analyzing software "WinROOF" of Mitani
Corp., the island component diameter was determined from
hypothetical diameter calculated from area of the island component,
provided that the island component is a circle. The number of
islands to be measured was 100 islands per one sample, and its
distribution was taken as the island component diameter
distribution.
O. Blend Ratio (Weight Ratio) of Component A/Component B in Core
Component (Polymer Alloy) in Sheath/Core Type Composite Fiber
[0286] Weights of the component A and the component B were
respectively metered at providing them to a melt spinning, and a
blend ratio of the component A and the component B was
calculated.
[0287] In the case where it is difficult to respectively meter the
component A and the component B in production process, the blend
ratio (weight ratio) of component A/component B was calculated from
sheath/core type composite fiber. The core component of sheath/core
type composite fiber may contain the component A, the component B
and other small amount component, but in such a case, it is
possible to calculate the blend ratio (weight ratio) of component
A/component B by considering that the core component substantially
comprises only 2 components of the component A and the component B.
By using the image taken in the item O and by using the image
analyzing software "WinROOF" of Mitani Corp., total area of the
component A (Aa) and total area of the component B (Ab)
constituting the core component were determined, the blend ratio
was calculated by the following equation, provided that the
specific gravity of the component A was 1.26 and the specific
gravity of the component B was 1.14.
Component A/the component B=(Aa.times.1.26)/(Ab.times.1.14)
[0288] At this time, in the case where boundary line of the sheath
component and the core component in the cross-section was difficult
to decide, in the cross-section, taking a similar figure to fiber
cross-section circumscribing the component A which is present at
outermost layer and contains the component A in its inside only as
boundary line, sheath component and core component was
differentiated.
P. Minimum Value of Thickness of Sheath Component
[0289] By using the image taken in accordance with the observing
method of cross-section of crimped yarn described in the item L, a
thickness was measured at portion where, in the cross-section,
thickness of the sheath component is smallest. By randomly changing
sampling portion of cross-section slice of the crimped yarn, 10
sheets of image were prepared, and the above-mentioned measurement
was carried out for the respective images, and an average value was
taken as the minimum value of thickness of sheath component.
Q. Content of Aliphatic Polyester Resin (A)
[0290] 10 g sheath/core type composite fiber was taken out and its
weight (W1) was weighed by a balance as a sample. The sample was
immersed in 500 ml chloroform of 25.degree. C. at 24 hours, to
completely dissolve out the component A. The sheath/core type
composite fiber after dissolving out treatment was washed with
water, and after drying at 25.degree. C. for 24 hours, the fiber
weight (W2) was weighed. By using W1 and W2, the content of the
component A was calculated by the following equation:
Content of the component A(wt %)=(W1-W2).times.100/W1.
R. Fiber Thickness
[0291] By a sizing reel, 100 m crimped yarn was measured and taken
as a hank, weight of the crimped yarn of 100 m length was measured,
and a yarn thickness (dtex) was determined by multiplying the
weight 100 times. The measurement was repeated 3 times and its
average value was taken as yarn thickness (dtex). In addition,
single fiber thickness (dtex) was determined by dividing the yarn
thickness by number of filaments.
[0292] S. Strength and Elongation
[0293] A sample (crimped yarn) was measured by Tensilon UCT-100 of
Orientech Inc. in accordance with the constant rate elongation
method defined in JIS L1013 (chemical fiber filament yarn test
method, 1998). Grip length (sample length) was 200 mm. The
elongation at break was determined by the elongation at which
maximum strength in S-S curve was shown.
T. Boiling Water Shrinkage (Fusshouu)
[0294] A sample (crimped yarn) was immersed in boiling water for 15
minutes and the boiling water shrinkage was determined by
dimensional change between before and after the immersion.
Boiling water shrinkage (%)=[(L.sub.0-L.sub.1)/L.sub.0].times.100
[0295] L.sub.0: Hank length after a sample was made into a hank and
measured under an initial load of 0.088 cN/dtex. [0296] L.sub.1:
Hank length measured under initial load of 0.088 cN/dtex after the
hank of which L0 was measured was treated by boiling water under no
load, and dried in the air.
U. Yarn Unevenness, U %
[0297] A sample (crimped yarn) was subjected to a U % (Normal)
measurement by using UT4-CX/m produced by Zellweger uster Inc., at
yarn speed: 200 m/min and measurement time: 1 minute.
V. Crimp Elongation Percentage after Boiling Water Treatment
[0298] A crimped yarn unwound from a package (crimped yarn wound
drum or bobbin) left in an atmosphere of atmospheric temperature
25.+-.5.degree. C. and relative humidity 60.+-.10% for 20 hours or
more was immersed in boiling water for 30 minutes or more under no
load. After the treatment, it was dried in the air for one day and
night (approximately for 24 hours) under the above-mentioned
atmosphere, and this was used as a sample of crimped yarn after
boiling water treatment. This sample was loaded by an initial load
of 1.8 mg/dtex, and after passing 30 seconds, a marking was made at
sample length of 50 cm (L1). Subsequently, after passing 30 seconds
after a load for measurement of 90 mg/dtex instead of the initial
load was loaded, a sample length (L2) was measured. By the
following equation, crimp elongation percentage after boiling water
treatment (%) was determined:
Crimp elongation percentage (%)=[(L2-L1)/L1].times.100.
W. Crimp Elongation Percentage Under Load after Boiling Water
Treatment (Elongation Percentage Under Load)
[0299] Crimp elongation percentage was determined in the same way
as in the item M except changing to a load of 2 mg/dtex to the
crimped yarn when it was subjected to a boiling water treatment,
and the value was taken as the elongation percentage under
load.
X. CF Value
[0300] It was measured in accordance with the condition shown in
the degree of interlace of JIS L1013 (Chemical fiber, filament yarn
test method) 7.13. The number of tests was 50 times and CF value
(Coherence Factor) was determined by the following equation from
average value
[0301] L (mm) of interlacing length:
CF value=1000/L.
Y. Non-Circularity
[0302] A cross-section of a sample (crimped yarn) was cut out, and
the non-circularity was determined by the following equation from
diameter D1 of circumscribed circle of the single fiber
cross-section and diameter D2 of inscribed circle of the single
fiber cross-section:
Non-circularity=D1/D2.
Z. Non-Circularity of Sheath/Core Type Composite Fiber
[0303] By using an image taken in accordance with the observing
method of the cross-section of crimped yarn described in the item
L, it was determined by the following equation from diameter D1 of
circumscribed circle of cross-section of the crimped fiber and
diameter D2 of inscribed circle of single fiber cross-section. In
the same way, non-circularity of the core portion was also
determined by the following equation from diameter D3 of
circumscribed circle and diameter D4 of inscribed circle of the
cross-section of core portion:
Non-circularity=D1/D2
Non-circularity=D3/D4.
AA. Evaluation of Abrasion Resistance of Stretched Yarn
[0304] A sandpaper (# P600) was wound and fixed to a roller
rotating at a constant speed, and one end of a stretched yarn was
fixed to a wall and the other end was loaded as shown in FIG. 3,
and the stretched yarn was abraded by rotating the roller while
traversing the stretched yarn at a constant speed to thereby count
a number of roller rotations at which the stretched yarn was
broken. Measuring conditions are shown in the following: [0305]
Diameter of rotating body: 80 mm [0306] Contact length of yarn:
62.8 mm [0307] Contact angle of yarn: 90.degree. [0308] Number of
roller rotations: 160 rpm [0309] Traverse oscillation: 10 mm [0310]
Traverse speed: 3 times [0311] Load for measurement: 0.06
cN/dtex.
BB. Abrasion Resistance of Crimped Yarn
[0312] By using twine abrasion tester produced by Ando Tekkosho,
#P600 sandpaper was wound on a roller, and a number of roller
rotations up to a yarn break was measured in the following
conditions: [0313] Diameter of rotating body: 40 mm [0314] Contact
length of yarn: 110 mm [0315] Number of roller rotations: 200 rpm
[0316] Load for measurement: 0.4 cN/dtex.
CC. Average Particle Diameter D50 of Crystal Nucleating Agent and
Content of Crystal Nucleating Agent of 10 .mu.m or More
[0317] By using SALD-2000J produced by Shimadzu Corp. and by a
laser diffraction method, average particle diameter D50 of crystal
nucleating agent (.mu.m) was measured. In addition, from the
obtained particle diameter distribution, a volume % of the crystal
nucleating agent of 10 .mu.m or more was determined.
DD. Evaluation of Spinnability
[0318] Depending on frequency of yarn break for obtaining 100 kg
cheese package, the evaluation of spinnability was carried out. The
evaluation was classified to 4 classes of excellent (double
circle), good (.smallcircle.), fair (.DELTA.), poor (x). [0319]
Double circle: no yarn break [0320] .smallcircle.: Yarn break 1 to
5 times [0321] .DELTA.: Yarn break 6 to 10 times [0322] x: Yarn
break 11 or more
EE. Abrasion Resistance of Carpet (Abrasion Loss Ratio)
[0323] Two crimped yarns subjected to S-twist and Z-twist were
paralleled and twisted and wound. The wound yarn in cheese package
was treated to dye with a metal-complex dye ("Irgaran Red 4GL"
(produced by Ciba-Geigy AG)) at 0.6% owf, bath ratio 1:50, pH=7 and
at 98.degree. C. for 60 minutes. Furthermore, it was washed and hot
air dried at 50.degree. C. for 24 hours to thereby obtain a dyed
twisted yarn. After the twisted yarn was tufted to a PP spunbond
non-woven fabric as a front yarn, a backing material was coated on
reverse side of base fabric and dried to thereby obtain a tufting
carpet (weight 1200 g/m.sup.2).
[0324] The above-mentioned tufting carpet was cut out in a circular
shape of diameter 120 mm, and made a 6 mm hole at its center to
make a test piece. After measuring weight W0 of the test piece, it
was fixed to a taber abrasion tester (Rotary Abaster) prescribed in
ASTM D 1175 (1994) with its surface upside, and carried out an
abrasion test with H#18 abrasion wheel at compressive load 1 kgf
(9.8N), sample holder rotation speed 70 rpm and number of abrasion
5500 times, and sample weight W1 after the abrasion test was
measured. The abrasion loss ratio was calculated from these data
and by the following equation:
Abrasion loss ratio (%)=(W0-W1).times.100/(W2.times.A1/A0) [0325]
W0: Weight (g) of circular carpet before measurement [0326] W1:
Weight (g) of circular carpet after measurement [0327] W2: Weight
of carpet (g/m.sup.2) [0328] A0: Total area of circular carpet
(m.sup.2) [0329] A1: Total area contacting with abrasion wheel
(m.sup.2).
FF. Touch of Carpet (Softness) and Appearance (Glossy Texture)
[0330] The carpet was treated to dye with a metal-complex dye
("Irgaran Red 4GL" (produced by Ciba-Geigy AG)) at 0.6% owf, bath
ratio 1:50, pH=7 and at 98.degree. C. for 60 minutes. A touch
(softness) when the dyed carpet was pushed with palm and glossy
texture or gloss unevenness was confirmed under sunlight by visual
inspection to thereby evaluate touch and appearance in 4 classes,
respectively. [0331] Double circle extremely excellent [0332]
.smallcircle. . . . excellent [0333] .DELTA. . . . equal to
conventional one [0334] x . . . inferior to conventional one
GG. Peeling Resistance of Sheath/Core Composite Interface of
Sheath/Core Type Composite Fiber
[0335] A circular knit fabric comprising the crimped yarn was
prepared and the circular knit was treated to dye with a
metal-complex dye ("Irgaran Red 4GL" (produced by Ciba-Geigy AG))
at 0.6% owf, bath ratio 1:50 (as circular knit fabric), pH=7 and at
98.degree. C. for 60 minutes. After the dyeing, washed with water
and hot air dried at 50.degree. C. for 24 hours to obtain a dyed
circular knit fabric. From the dyed circular knit fabric, narrow
card shaped pieces of 50.times.100 mm were cut out as samples, and
after subjecting to crease-flex abrasion by using Scott type
crease-flex abrasion tester (SCOTT TYPE CREASE-FLEX ABRATION
TESTER, produced by Daiei Kagaku Seiki Mfg, Co., model: CF-10N), at
number of tests 1000 times, chuck distance 0 mm, abrasion stroke 45
mm and press load 0.5 kg, the sample was taken out, and appearance
change of where the crease-flex abrasion was imparted was evaluated
by the following criteria. For the same circular knit, the
measurement was carried out 5 times, and overall evaluation was
determined by total points of the respective evaluations.
[0336] <Evaluation Criteria> [0337] 5 points: No appearance
change [0338] 4 points: Partially, color loss was found. [0339] 3
points: Color loss was found and partially, pilling was found.
[0340] 2 points: Whitening was found and many pilings were found.
[0341] 1 point: Whitening was found, many pilings were found and a
hole opening was also found.
[0342] <Overall Evaluation> [0343] Double circle (excellent):
21 to 25 points [0344] .smallcircle. (good): 16 to 20 points [0345]
.DELTA. (fair): 11 to 15 points [0346] x (poor): 5 to 10
points.
HH. Abrasion Loss Ratio of Carpet
[0347] According to JIS L1096:1999 8.17.3 Taber-type method, by
using H-18 abrasion wheel and by loading 1 kgf (9.8N) load to
respective abrasion wheels of left-and-right pair, the carpet was
subjected to an abrasion by rotating a predetermined number of
rotations, and then from weights of unabraded portion and abraded
portion (refer to JIS L1096:1999 FIG. 20), abrasion loss ratio (%)
was calculated by the following equation:
Abrasion loss ratio (%)=[(pile weight of unabraded portion-pile
weight of abraded portion)/pile weight of abraded
portion].times.100
[0348] Two conditions of number of rotations of 300 times and 5500
times were employed.
II. Abrasion Loss Ratio after Wet Heat Degradation
[0349] An abrasion loss ratio was determined in the same way as
above-mentioned item HH for a carpet after being treated under
atmosphere of temperature 50.degree. C. and humidity 95% for 1200
hours. However, the number of rations was 1000 times.
JJ. Heat Resistance of Carpet (Line Mat)
[0350] Appearance change was evaluated by pressing at molding
temperature 150.degree. C. by 300t press machine produced by Miura
Press Seisakusho. [0351] .circleincircle.: No change. [0352]
.smallcircle.: A slight pressing mark was observed. [0353] x:
Fusion bond of pile occurred.
KK. Color Brightness
[0354] A carpet in which the dyed yarn was used was visually
inspected and evaluated in the following criteria. [0355]
.circleincircle.: Particularly excellent. [0356] .smallcircle.:
Excellent. [0357] .DELTA.: No difference compared to other
synthetic fiber.
LL. Strength of Car Sheet Fabric
[0358] According to the labeled strip method of JIS L 1096:1999
8.12.1 A method (strip method), at atmospheric temperature
20.degree. C., 3 test pieces for longitudinally and transversely,
respectively, were sampled, yarns were removed from both sides of
width to adjust to a width of 30 mm, and a strength at break was
measured by constant speed stretch type (Autograph (AG-G) produced
by Shimadzu Corp.) tester when tested at grip distance 150 mm and
tensile speed 200 mm/min, and calculated an average value of the 6
sheets.
MM. Strength Retention of Car Sheet Fabric in 90.degree. C.
Atmosphere
[0359] Except changing the atmospheric temperature to 90.degree.
C., fabric strength was measured in the same way as above-mentioned
item LL, and the strength retention was calculated by the following
equation:
Strength retention of fabric (%)=(strength in 90.degree. C.
atmosphere/strength in 20.degree. C. atmosphere).times.100.
NN. Abrasion Loss of Car Sheet Fabric
[0360] According to JIS L 1096:1999 8.17.3 taber type method, by
using H-18 abrasion wheel and by loading 0.5 kgf (4.9N) load to
respective abrasion wheels of left-and-right pair, the carpet was
subjected to an abrasion by rotating 3,000 times, and then weight
loss of the fabric was measured.
Synthesis Example 1
Production of Polylactic Acid
[0361] A lactide produced from L lactic acid of optical purity
99.8% was polymerized in a presence of bis(2-ethylhexanoate) tin
catalyst (mol ratio of lactide:catalyst=10000:1) under nitrogen
atmosphere at 180.degree. C. for 240 minutes to thereby obtain a
polylactic acid P1. Weight average molecular weight of the obtained
polylactic acid was 233,000. An amount of residual lactide was 0.12
wt %.
Synthesis Example 2
Production of Polylactic Acid Containing 10 wt %
Polycarbodiimide
[0362] After drying P1 and polycarbodiimide "LA-1" produced by
Nishinbo Industries, Inc., they were fed to a twin screw kneading
extruding machine such that P1:LA-1=90:10 (weight ratio), and
kneaded at cylinder temperature 200.degree. C. to thereby obtain
polylactic acid P2 containing 10 wt % LA-1. The amount of residual
lactide of the obtained polylactic acid was 0.14 wt %.
Synthesis Example 3
Production of Polylactic Acid
[0363] A lactide produced from L lactic acid of optical purity
99.8% was polymerized in a presence of bis(2-ethylhexanoate) tin
catalyst (mol ratio of lactide:catalyst=10000:1) under nitrogen
atmosphere at 180.degree. C. for 150 minutes to thereby obtain
polylactic acid P3. Weight average molecular weight of the obtained
polylactic acid was 150,000. The amount of residual lactide was
0.10 wt %.
Synthesis Example 4
Production of Polylactic Acid (P4)
[0364] A lactide of optical purity 99.5% produced from L lactic
acid was polymerized in the presence of bis(2-ethylhexanoate) tin
catalyst (mol ratio of lactide:catalyst=10000:1) under nitrogen
atmosphere at 180.degree. C. for 220 minutes to thereby obtain a
polylactic acid (P4). Weight average molecular weight of the
obtained polylactic acid (P4) was 210,000. The amount of residual
lactide was 0.13 wt %. Of the polymer (P4), melting point was
170.degree. C., heat capacity of melting peak was 45 J/g, melt
viscosity was 200 Pasec.sup.-1 and relative viscosity was 3.42.
Synthesis Example 5
Production of Polylactic Acid (P5)
[0365] A lactide produced from L lactic acid of optical purity
99.5% was polymerized in the presence of bis(2-ethylhexanoate) tin
catalyst (mol ratio of lactide:catalyst=10000:1) under nitrogen
atmosphere at 180.degree. C. for 350 minutes to thereby obtain a
polylactic acid (P5). Weight average molecular weight of the
obtained polylactic acid (P5) was 260,000. The amount of residual
lactide was 0.14 wt %. Of the polymer (P5), melting point was
170.degree. C. and heat capacity of melting point peak was 45 J/g.
Melt viscosity was 300 Pasec.sup.-1. Relative viscosity was
3.76.
Synthesis Example 6
Production of Polylactic Acid (P6)
[0366] A lactide produced from L lactic acid of optical purity
99.5% was polymerized in the presence of bis(2-ethylhexanoate) tin
catalyst (mol ratio of lactide:catalyst=10000:1) under nitrogen
atmosphere at 180.degree. C. for 150 minutes to thereby obtain a
polylactic acid (P6). Weight average molecular weight the obtained
polylactic acid (P6) was 150,000. The amount of residual lactide
was 0.10 wt %. Of the polymer (P6), melting point was 170.degree.
C., heat capacity of melting peak was 48 J/g, melt viscosity was
120 Pasec.sup.-1 and relative viscosity was 3.04.
Synthesis Example 7
Production of Polylactic Acid (P7)
[0367] A lactide produced from L lactic acid of optical purity
99.5% and lactide produced from D lactic acid of optical purity
99.5% was polymerized in a presence of bis(2-ethylhexanoate) tin
catalyst (mol ratio of L lactic acid lactide:D lactic acid
lactide:catalyst=8900:1100:1) under nitrogen atmosphere at
180.degree. C. for 220 minutes to thereby obtain a polylactic acid
(P7). Weight average molecular weight of the obtained polylactic
acid (P7) was 210,000. The amount of residual lactide was 0.12 wt
%. Of the polymer (P7), melting point was 130.degree. C., heat
capacity of melting peak was 38 J/g and melt viscosity was 200
Pasec.sup.-1. Relative viscosity was 3.42.
Synthesis Example 8
Production of Polylactic Acid (P8) Containing Polycarbodiimide 10
wt %
[0368] After drying P4 and the component C (polycarbodiimide "LA-1"
produced by Nishinbo Industries, Inc.), they were fed to a twin
screw kneading extruding machine such that P4:LA-1=90:10 (weight
ratio), and kneaded at cylinder temperature 200.degree. C. to
thereby obtain a polylactic acid (P8) containing LA-1 10 wt %. The
amount of residual lactide of the obtained polylactic acid (P8) was
0.15 wt %. Of the polymer (P8), melting point was 170.degree. C.,
heat capacity of melting peak was 44 J/g, melt viscosity was 190
Pasec.sup.-1 and relative viscosity was 3.38.
Synthesis Example 9
Production of Polylactic Acid (P9) Containing MADGIC 10 wt %
[0369] After drying P4 and the component C (monoallyl diglycidyl
isocyanuric acid ((hereafter, referred to as MADGIC) produced by
Shikoku Chemicals Corp.), they were fed to a twin screw kneading
extruding machine such that P4:MADGIC=90:10 (weight ratio), and
kneaded at cylinder temperature 200.degree. C. to thereby obtain a
polylactic acid (P9) containing MADGIC 10 wt %. The amount of
residual lactide of the obtained polylactic acid (P9) was 0.15 wt
%. Of the polymer (P9), melting point was 170.degree. C., heat
capacity of melting peak was 44 J/g, melt viscosity was 190
Pasec.sup.-1 and relative viscosity was 3.38.
Synthesis Example 10
Production of Polylactic Acid (P10) Containing 10 wt % of Compound
of Which Main Chain is Ethylene-Glycidyl Acrylate and Grafted with
Polymethyl Methacrylate
[0370] After drying P4 and the component C ("Modiper A4200"
(hereafter, abbreviated as "Modiper") produced by NOF Corp.), they
were fed to a twin screw kneading extruding machine such that
P4:"Modiper"=80:20 (weight ratio), and kneaded at cylinder
temperature 200.degree. C. to thereby obtain a polylactic acid
(P10) containing "Modiper" 20 wt %. The amount of residual lactide
of the obtained polylactic acid (P10) was 0.15 wt %. Of the polymer
(P10), melting point was 170.degree. C., heat capacity of melting
peak was 44 J/g, melt viscosity was 190 Pasec.sup.-1 and relative
viscosity was 3.38.
Example 1
[0371] The polylactic acid P1 (melting point 177.degree. C.) as the
component A, nylon 6 of relative viscosity in sulfuric acid 2.15
(melting point 225.degree. C.) as the component B were respectively
dried to control water content of the component A to 50 to 100 ppm
and water content of the component B to 100 to 300 ppm, and chip
blended in a blend ratio (weight ratio) P1/nylon 6=30/70, and fed
to the spinning hopper 1 of a spinning machine provided with a twin
screw kneading machine shown in FIG. 6 to thereby introduce into
the twin screw extruding/kneading machine 2, and metered and
discharged a molten polymer by the spinning block 3 to thereby
introduce the molten polymer to the spinning pack 4 assembled
therein and spun from the spinneret 5. To the spinneret, the
following described Y type holes were provided. At this time, the
circular chimney 6 (cooling length 30 cm) was installed such that
the uppermost end of blow-off hole was positioned 3 cm beneath the
spinneret surface to thereby cool and solidify the yarn 7 and oiled
in 2 steps by the oiling device 8 and the oiling device 9.
Furthermore, after it was taken up via the stretch roll 10, while
setting the temperature of the first heating roll 11 (hereafter,
described as 1 FR) to 60.degree. C. and spinning speed to 700
m/min, while adjusting the temperature of the second heating roll
12 (hereafter, described as 1 DR) to 120.degree. C., first stage
stretching (stretch ratio: 2.7 times) was carried out at 1890
m/min, and furthermore, while adjusting the temperature of the
third heating roll 13 (hereafter, described as 2 DR) to 157.degree.
C., second stage stretching (stretch ratio: 1.37 times) was carried
out at 2590 m/min, successively, subjected to a hot and compressed
air treatment by the air stuffer 14 at nozzle temperature
220.degree. C. to carry out crimp processing to form a
3-dimensional crimp, and after taking up by contacting with the
cooling drum 15, via the tension measuring detector 16, taken up by
the take-up roll 17, and while interlacing by the interlacing
nozzle 18, wound by the winder 19 under winding tension 12.0 g
(0.08 cN/dtex) and at winding speed 2200 m/min (a speed 15% lower
than 2 DR speed). The obtained polylactic acid crimped yarn was
1500 dtex, 96 filaments. The melt spinning condition was as
follows. The linear discharge velocity in spinneret hole under the
following conditions is 0.184 m/sec and the elongation at break of
the stretched yarn samples at the exit of 2 DR was 35%: [0372] Twin
screw extruding machine temperature: 225.degree. C. [0373] Shear
rate at kneading: approximately 2000 sec.sup.-1 [0374] Spinning
temperature: 240.degree. C. [0375] Filtering layer: 46#, white
morundum sand filled [0376] Filter: 20 .mu.m nonwoven fabric filter
(Dynaloy) [0377] Spinneret: slit width 0.14 mm, slit length 0.7 mm,
depth of hole 0.6 mm [0378] Out put: 330 g/min (1 pack 1 yarn, 96
filaments) [0379] Cooling: cooling air temperature 19.degree. C.,
wind speed 0.55 m/sec [0380] Oiling agent: oiling agent in which
polyether-based oiling agent 15 and low viscosity mineral oil 85
was mixed in this ratio was imparted in a ratio of 10% (1.5% owf as
pure oiling agent component) to yarn.
[0381] The crimped yarn was sampled approximately 100 kg but in all
processes of spinning, stretching and bulking processing, a yarn
break and a single fiber break did not occur and the processes were
very stable.
[0382] When an observation by TEM of cross-section of the obtained
fiber was carried out, it was found that a uniformly dispersed
sea/island structure was formed, and exposed area ratio of
polylactic acid with respect to fiber surface area was 1.5%. The
island domain size was 0.03 to 0.3 .mu.m in diameter equivalent.
When a section of the fiber cross-section was subjected to an
alkali etching to dissolve out polylactic acid and observed, it was
confirmed that the island component was dropout and polylactic acid
constituted the island component. The grooves as shown in FIG. 2
were formed on the fiber surface and an average width of the
grooves was 0.26 .mu.m, aspect ratio (length of grooves/width of
groove) was 20. The obtained fiber showed good fiber physical
properties that tensile strength was 2.8 cN/dtex, residual
elongation: 48%, boiling water shrinkage: 2.8%, yarn unevenness U
%: 0.8%, crimp elongation percentage: 12% and non-circularity: 2.5.
The melting points by DSC were around 175.degree. C. (polylactic
acid) and around 225.degree. C. (nylon 6), i.e., melting peaks
based on the respective components were observed. The carboxyl
group terminal concentration of polylactic acid extracted from the
fiber was 18 eq/ton. Further, the number of rotations up to yarn
break by the abrasion test was 101 rotations, i.e., a good abrasion
resistance was shown. Further, when a carpet was prepared by using
the crimped yarn and evaluated, it was found that an abrasion loss
ratio was 25.5% and it showed a very good abrasion resistance as a
carpet. A touch was soft and had a moderate hardness and it was a
carpet having a dewy and silky glossiness.
Example 2
[0383] A BCF yarn was obtained in the same way as Example 1 except
changing the blend ratio of P1/the component B to 10/90. The
spinnability in Example 2 was very stable as Example 1. When an
observation by TEM of cross-section of the obtained fiber was
carried out, it was found that a uniformly dispersed sea/island
structure was formed, and exposed area ratio of polylactic acid
with respect to fiber surface area was 0.1%. An island domain size
was 0.01 to 0.15 .mu.m in diameter equivalent, i.e., dispersion
size of island component was smaller than that of Example 1. When a
section of the fiber cross-section was subjected to an alkali
etching to thereby dissolve out polylactic acid and observed, it
was confirmed that the island component was dropout and polylactic
acid constituted the island component.
[0384] Furthermore, non-circularity of the obtained fiber was 2.4
and fiber physical properties were also good. The melting points by
DSC were around 175.degree. C. (polylactic acid) and around
225.degree. C. (nylon 6), i.e., melting peaks based on the
respective components were observed. The number of rotations up to
yarn break by the abrasion test of the obtained multifilament was
185 rotations and it was superior to that of Example 1.
[0385] Furthermore, when a carpet was prepared by using the crimped
yarn and evaluated, it was more excellent than that of Example 1 in
abrasion resistance, and a carpet having a soft touch was obtained.
However, glossy texture was inferior to that of Example 1.
Example 3
[0386] A BCF yarn was obtained in the same way as Example 1 except
changing the blend ratio of P1/the component B to 40/60.
Spinnability in Example 3 was very stable as Example 1. When an
observation by TEM of cross-section of the obtained fiber was
carried out, a uniformly dispersed sea/island structure was formed,
and exposed area ratio of polylactic acid with respect to fiber
surface area was 3.2%. The island domain size was 0.03 to 0.8 .mu.m
in diameter equivalent and dispersion size of the island component
was smaller than that of Example 1. When a carpet was prepared by
using the crimped yarn and evaluated, it was found that the carpet
of Example 1 was superior in abrasion resistance, but the carpet of
this example was more excellent than that of conventional one in
both of touch and appearance.
Example 4
[0387] A BCF yarn was obtained in the same way as Example 1 except
changing the blend ratio of P1/the component B to 5/95.
Spinnability in Example 4 was very stable as Example 1. When an
observation by TEM of a cross-section of the obtained fiber was
carried out, it was found that a uniformly dispersed sea/island
structure was formed, and exposed area ratio of polylactic acid
with respect to fiber surface area was 0%. The island domain size
was 0.01 to 0.1 .mu.m in diameter equivalent, i.e., dispersion size
of the island component was extremely small, and number of islands
was also small. Almost no groove was formed on fiber surface of the
crimped yarn. When a carpet was prepared by using the crimped yarn
and evaluated, similar to Example 1, although it has a high
softness and an excellent touch, its glossy texture was in the same
level as that of conventional one.
Example 5
[0388] A BCF yarn was obtained in the same way as Example 1 except
using nylon 6 of relative viscosity in sulfuric acid 2.05 (melting
point 225.degree. C.) as the component B and changing the blend
ratio of P1/the component B to 47/53. In Example 5, due to Barus
effect just beneath spinneret, swelling of extruded flow was
slightly large. When crimped yarn was sampled 100 kg, yarn break
occurred 2 times and its spinnability was slightly inferior to that
of Example 1. When an observation by TEM of a cross-section of the
obtained fiber was carried out, it was found that a uniformly
dispersed sea/island structure was formed, and exposed area ratio
of polylactic acid with respect to fiber surface area was 5.0%. The
island domain size was 0.03 to 0.8 .mu.m in diameter equivalent and
dispersion size of island component was slightly larger than that
of Example 1. When a carpet was prepared by using the crimped yarn
and evaluated, abrasion resistance was better in Example 1 than in
this example. Although its touch was somewhat hard and coarse, it
had a dewy and silky glossiness.
Comparative Example 1
[0389] A BCF yarn was obtained in the same way as Example 1 except
using only the component A (polylactic acid P1). Spinnability of
comparative example 1 was stable as that of Example 1. In the
obtained crimped yarn, the number of rotations up to yarn break by
the abrasion test was 9 rotations, i.e., its abrasion resistance
was extremely poor. When a carpet was prepared by using the crimped
yarn and evaluated, abrasion loss ratio was 89% and it was in a
level of which application was considerably limited.
Example 6
[0390] A BCF yarn was obtained in the same way as Example 1 except
using the polylactic acid P3 (melting point 178.degree. C.) as the
component A and except changing spinning condition as follows:
[0391] Shear rate of twin screw kneading machine: approximately 280
sec.sup.-1 [0392] Filtering layer constitution: filled with glass
beads of .phi.1 mm [0393] Filter: #200 metal mesh filter.
[0394] In Example 6, the thinning point just beneath spinneret was
not stable, and discharged flow was slightly unstable. When crimped
yarn was sampled 100 kg, yarn break occurred 3 times and
spinnability was slightly inferior to that of Example 1. When an
observation by TEM of a cross-section of the obtained fiber was
carried out, it was found that it had an sea/island structure, but
exposed area ratio of polylactic acid with respect to fiber surface
area was 1.9%. The island domain size in diameter equivalent was
0.3 to 2.5 .mu.m, i.e., dispersion size of island component was
large and its distribution was wide. Uster unevenness U % which
indicates yarn unevenness was high as 2.1%, and it was found that
there was a thickness unevenness along the longitudinal direction
of the yarn. When a carpet was prepared by using the crimped yarn
and evaluated, it was found that an abrasion loss ratio was
approximately 2 times compared to that of Example 1. Its touch was
of partially hard and coarse feeling, and glossy texture was also
in the same level as conventional one.
Comparative Example 2
[0395] A BCF yarn was obtained in the same way as Example 1 except
using the polylactic acid P3 (melting point 178.degree. C.) as the
component A and nylon 6 (melting point 225.degree. C.) of relative
viscosity in sulfuric acid 2.90 as the component B. In Comparative
example 2, an extremely large swelling was occurred due to Barus
effect just beneath spinneret and a wave phenomena in which the
thinning point goes up and down occurred and it was an unstable
condition. When crimped yarn was sampled 100 kg, yarn break
frequently occurred as 17 times, and spinnability was considerably
bad. When an observation by TEM of a cross-section of the obtained
fiber was carried out, although it had a sea/island structure, the
island component was dyed. At this time, when polylactic acid was
dissolved out by alkali etching, only the island component was
left, and it was found that the polylactic acid had formed the sea
component. In the crimped yarn, strength was low as 1.1 cN/dtex,
yarn unevenness U % was also extremely bad as 4.5%. When a carpet
was prepared by using the crimped yarn and evaluated, it was found
that an abrasion loss ratio was 87%, which is in the same level as
that of polylactic acid alone (Comparative example 1), and its
application was considerably limited.
TABLE-US-00002 TABLE 1 Comparative Comparative Example 1 Example 2
Example 3 Example 4 Example 5 example 1 Example 6 example 2
Component A PLLA PLLA PLLA PLLA PLLA PLLA PLLA PLLA Weight average
molecular weight 23.30,000 23.30,000 23.30,000 23.30,000 23.30,000
23.30,000 15.00,000 15.00,000 Melting point (.degree. C.) 177 177
177 177 177 177 178 178 Amount of residual lactide (wt %) 0.12 0.12
0.12 0.12 0.12 0.12 0.10 0.10 Melt viscosity (Pa s) 225 225 225 225
225 225 116 116 Component B N6 N6 N6 N6 N6 -- N6 N6 Relative
viscosity (or inherent 2.15 2.15 2.15 2.15 2.05 -- 2.15 2.90
viscosity) Melting point (.degree. C.) 225 225 225 225 222 -- 225
225 Heat of crystal fusion (J/g) 78 78 78 78 82 -- 78 76 Melt
viscosity (Pa s) 58 58 58 58 43 -- 58 250 Blend ratio 30/70 10/90
40/60 5/95 47/53 100/0 40/60 30/70 (component A/component B, %)
Melt viscosity ratio (.eta.b/.eta.a) 0.26 0.26 0.26 0.26 0.19 --
0.50 1.11 Physical properties of fiber Island component PLLA PLLA
PLLA PLLA PLLA -- PLLA N6 Sea component N6 N6 N6 N6 N6 -- N6 PLLA
Exposed area ratio (%) of 1.5 0.1 3.2 0 5.0 0 1.9 83.3 Component A
Domain size of the island 0.03 to 0.3 0.01 to 0.15 0.03 to 0.8 0.01
to 0.1 0.03 to 0.8 -- 0.3 to 2.5 -- component (.mu.m) Width of
grooves of fiber surface 0.26 0.12 0.36 -- 0.38 -- 0.85 -- layer
(.mu.m) Aspect ratio of groove of fiber 20 17 24 -- 25 -- 16 --
surface layer Number of grooves of fiber 7 1 10 -- 13 -- 1 --
surface layer (grooves) Carboxyl terminal 18 20 17 20 20 17 18 18
concentration (eq/ton) Non-circularity of fiber 2.5 2.4 2.6 2.3 2.3
3.0 2.1 2.8 cross-section Fiber thickness (dtex) 1500 1500 1500
1500 1500 1500 1500 1500 Strength (cN/dtex) 2.8 3.0 2.6 3.0 2.4 1.5
2.2 1.1 Elongation (%) 48 44 49 43 50 48 44 38 U % (%) 0.8 0.7 0.9
0.6 1.0 1.0 2.1 4.5 Boiling water shrinkage (%) 2.8 3.0 2.6 3.1 2.4
5.5 3.2 4.0 Wear resistance (number of 101 185 85 198 52 9 28 11
yarn break) Crimp elongation percentage (%) 12 13 10 13 8 4.5 9 2.8
Elongation percentage under 3.5 4 3 4 2.5 1.5 3 1 load (%) Physical
properties of fiber structure Abrasion loss ratio of carpet (%)
25.5 18.1 32.3 15.0 38.8 89 48.7 87 Touch of carpet (softness)
.circleincircle. .circleincircle. .largecircle. .circleincircle.
.DELTA. X .DELTA. X Appearance of carpet (glossy .circleincircle.
.DELTA. .circleincircle. .DELTA. .circleincircle. .DELTA. .DELTA. X
texture) Note) In the table, "PLLA" means "polylactic acid" and
"N6" means "nylon 6".
Example 7
[0396] A BCF yarn was obtained in the same way as Example 1 except
using nylon 11 of inherent viscosity 1.45 as the component B.
Spinnability in Example 7 was extremely stable as that of Example
1. When an observation by TEM of a cross-section of the obtained
fiber was carried out, it was found that a uniformly dispersed
sea/island structure was formed, and exposed area ratio of
polylactic acid with respect to fiber surface area was 0.9%. Island
domain size in diameter equivalent was 0.05 to 0.5 .mu.m. When a
section of the fiber cross-section was subjected to an alkali
etching to thereby dissolve out polylactic acid and observed, it
was confirmed that the island component was dropout and polylactic
acid constituted the island component.
[0397] Furthermore, when a carpet was prepared by using the crimped
yarn and evaluated, it was bulkier and of a higher quality than
that of Example 1, and its abrasion resistance was also excellent.
Both touch and appearance were very excellent as those of Example
1.
Example 8
[0398] A BCF yarn was obtained in the same way as Example 1 except
using nylon 610 (melting point 225.degree. C.) of relative
viscosity in sulfuric acid 2.15 as the component B. Spinnability of
Example 8 was extremely stable as that of Example 1. When an
observation by TEM of a cross-section of the obtained fiber was
carried out, a uniformly dispersed sea/island structure was formed,
and exposed area ratio of polylactic acid with respect to fiber
surface area was 1.2%. Island domain size in diameter equivalent
was 0.03 to 0.3 .mu.m. When a section of the fiber cross-section
was subjected to an alkali etching to thereby dissolve out
polylactic acid and observed, it was confirmed that the island
component was dropout and polylactic acid constituted the island
component. Further, when a carpet was prepared by using the crimped
yarn and evaluated, it was found that both touch and appearance
were excellent as those of Example 1.
Example 9
[0399] A BCF yarn was obtained in the same way as Example 1 except
using N6/N66 copolymerized nylon (melting point 198.degree. C.)
polymerized in a weight ratio of
.epsilon.-caprolactam/hexamethylene diammonium adipate (66
salt)=85/15 as the component B. Spinnability in Example 9 was
extremely stable as that of Example 1. When an observation by TEM
of a cross-section of the obtained fiber was carried out, a
uniformly dispersed sea/island structure was formed, and exposed
area ratio of polylactic acid with respect to fiber surface area
was 1.4%. Island domain size in diameter equivalent was 0.03 to
0.26 .mu.m. When a section of the fiber cross-section was subjected
to an alkali etching to thereby dissolve out polylactic acid and
observed, it was confirmed that the island component was dropout
and polylactic acid had constituted the island component. Further,
when a carpet was prepared by using the crimped yarn and evaluated,
it was bulkier than that of Example 1. Both touch and appearance
were very excellent as those of Example 1.
Example 10
[0400] A BCF yarn was used in the same way as Example 1 except
using the polylactic acid P2 (polycarbodiimide "LA-1": 10 wt %)
containing a compatibilizer (component C) and changing the blend
ratio to P1/the component B/P2=20/70/10 (concentration of the
component C with respect to total amount of the component A and the
component B: 1.0 wt %). Spinnability of Example 10 was extremely
stable as that of Example 1. When an observation by TEM of a
cross-section of the obtained fiber was carried out, a uniformly
dispersed sea/island structure was formed, and exposed area ratio
of polylactic acid with respect to fiber surface area was 1.1%.
Island domain size in diameter equivalent was 0.03 to 0.3 .mu.m.
Further, when a carpet was prepared by using the crimped yarn and
evaluated, its abrasion resistance was more excellent than that of
Example 1 as well as both touch and appearance were very excellent
as those of Example 1.
Comparative Example 3
[0401] A BCF yarn was obtained in the same way as Example 1 except
carrying out melt spinning by changing the spinning temperature to
270.degree. C. (Tmb+45.degree. C.). The melt viscosity of the
component A was 35 Pas and melt viscosity of the component B was 28
Pas (.eta.b/.eta.a=0.8) at the spinning temperature. In Comparative
example 3, a swelling occurred due to Barus effect just beneath
spinneret and discharged flow was slightly unstable. When crimped
yarn was sampled 100 kg, yarn break occurred 5 times, and
spinnability was slightly inferior to that of Example 1. When an
observation by TEM of a cross-section of the obtained fiber was
carried out, a portion where sea/island structure was partially
reversed and a portion where islands were connected to form a
co-continuous structure were coexisted. The strength was 1.4
cN/dtex which was approximately a half of that of Example 1 as well
as Uster unevenness U % which indicates yarn unevenness was high as
2.2%. When a carpet was prepared by using the crimped yarn and
evaluated, it was found that an abrasion loss ratio was extremely
poor as 76.5%, and its glossy texture was also inferior to that of
conventional one.
Comparative Example 4
[0402] A spinning was carried out in the same way as Example 3,
except changing the spinneret to a spinneret with a Y type hole of
which slit width 0.43 mm, slit length 2.15 mm and depth of hole 0.6
mm. Although swelling just beneath spinneret did not occur, but
thinning was not stable and it was impossible to spin. The linear
discharge velocity in spinneret hole in Comparative example 4 was
0.0195 m/sec.
Comparative Example 5
[0403] A spinning was carried out in the same way as Example 3
except changing the spinneret to a spinneret with a Y type hole of
which slit width 0.09 mm, slit length 0.45 mm and depth of hole 0.6
mm. In Comparative example 5, an extremely large swelling occurred
due to Barus effect just beneath the spinneret and, accordingly, a
wave phenomena in which the thinning point goes up and down
occurred and it was impossible to spin.
TABLE-US-00003 TABLE 2 Com- Comparative Comparative parative
Example 7 Example 8 Example 9 Example 10 example 3 example 4
example 5 Component A PLLA PLLA PLLA PLLA PLLA PLLA PLLA Weight
average molecular weight 23.30,000 23.30,000 23.30,000 23.30,000
23.30,000 23.30,000 23.30,000 Melting point (.degree. C.) 177 177
177 177 177 177 177 Amount of residual lactide (wt %) 0.12 0.12
0.12 0.12 0.12 0.12 0.12 Melt viscosity (Pa s) 225 225 225 225 35
225 225 Component B N11 N610 N6/66 copolymer N6 N6 N6 N6 Relative
viscosity (or inherent viscosity) 1.45 2.15 2.15 2.15 2.15 2.15
2.15 Melting point (.degree. C.) 186 225 198 225 225 225 225 Heat
of crystal fusion (J/g) 76 78 63 78 78 78 78 Melt viscosity (Pa s)
89 63 61 58 28 58 58 Component C -- -- -- LA-1 -- -- -- Heat loss
ratio at 200.degree. C. (%) -- -- -- 0.3 -- -- -- Content (wt %) --
-- -- 1.0 -- -- -- Blend ratio (component A/component B, %) 30/70
30/70 30/70 29.8/70.2 30/70 40/60 40/60 Melt viscosity ratio
(.eta.b/.eta.a) 0.40 0.28 0.27 0.27 0.80 0.71 0.71 Physical
properties of fiber Island component PLLA PLLA PLLA PLLA PLLA/N6 --
-- Sea component N11 N610 N6/66 copolymer N6 PLLA/N6 -- -- Exposed
area ratio (%) of Component A 0.9 1.2 1.4 1.1 11.8 -- -- Domain
size of the island component (.mu.m) 0.05 to 0.5 0.03 to 0.3 0.03
to 0.26 0.03 to 0.3 -- -- -- Width of grooves of fiber surface
layer (.mu.m) 0.26 0.23 0.25 0.24 0.46 -- -- Aspect ratio of groove
of fiber surface layer 21 22 22 19 15 -- -- Number of grooves of
fiber surface layer (grooves) 5 8 8 8 2 -- -- Carboxyl terminal
concentration (eq/ton) 18 18 18 5 63 -- -- Non-circularity of fiber
cross-section 2.7 2.5 2.6 2.7 1.5 -- -- Fiber thickness (dtex) 1500
1500 1500 1500 1500 -- -- Strength (cN/dtex) 2.5 2.2 2.4 2.7 1.4 --
-- Elongation (%) 43 48 45 42 83 -- -- U % (%) 0.8 0.8 1.0 1.0 2.2
-- -- Boiling water shrinkage (%) 2.2 3.3 4.0 3.7 2.3 -- --
Abrasion resistance (number of yarn break) 95 89 85 132 14 -- --
Crimp elongation percentage (%) 21 10 15 12 4.4 -- -- Elongation
percentage under load (%) 4.5 3 4 3.5 1.5 -- -- Physical properties
of fiber structure Abrasion loss ratio of carpet (%) 22.5 29.0 30.0
21.2 76.5 -- -- Touch of carpet (softness) .circleincircle.
.circleincircle. .circleincircle. .circleincircle. .largecircle. --
-- Appearance of carpet (glossy texture) .circleincircle.
.circleincircle. .circleincircle. .circleincircle. X -- -- Note) In
the table, "N11" means "nylon 11", "N610" means "nylon 610" and
"N6/66 copolymer" means "copolymerized nylon of nylon 6 and nylon
66".
Example 11
[0404] A BCF yarn was obtained in the same way as Example 1 except
changing the cooling air speed of the circular chimney to 0.1
nm/sec. In Example 11, swelling occurred due to Barus effect just
beneath spinneret, and a slight wave phenomena occurred.
Accordingly, in sampling of 100 kg, yarn break occurred 2 times. In
the obtained crimped yarn, strength was 1.3 cN/dtex which is
approximately a half of that of Example 1 as well as Uster
unevenness U % which indicates yarn unevenness was high as 3.3%.
When a carpet was prepared by using the crimped yarn and evaluated,
it was found that an abrasion loss ratio was slightly low as 46.8%
and it had a slightly hard and coarse touch, but had a silky glossy
texture and appearance was good.
Example 12
[0405] A BCF yarn was obtained in the same way as Example 1 except
changing the out put to 277 g/min, carrying out second stage
stretching (stretch ratio: 1.15 times) with 2 DR speed of 2173
m/min and changing the winding speed to 1847 m/min (a speed lower
than 2 DR speed by 15%). Elongation at break of stretched yarn
samples at the exit of 2 DR was 76%. In the obtained crimped yarn,
strength was 1.8 cN/dtex which was approximately 64% of the
strength of Example 1 and Uster unevenness U % which indicates yarn
unevenness was slightly high as 1.6%. When a carpet was prepared by
using the crimped yarn and evaluated, it was found that an abrasion
loss ratio was slightly high as 41.1%, but it was a level which
could be used in limited applications.
Example 13
[0406] A BCF yarn was obtained in the same way as Example 1 except
changing the set temperature at 2 DR to 130.degree. C. Spinnability
in Example 13 was extremely stable as that of Example 1. When an
observation by TEM of a cross-section of the obtained fiber was
carried out, it was found that a uniformly dispersed sea/island
structure was formed, and exposed area ratio of polylactic acid
with respect to fiber surface area was 1.5%. Island domain size in
diameter equivalent was 0.03 to 0.3 .mu.m which was the same level
as Example 1, but almost no groove was formed on fiber surface of
the crimped yarn. The crimp elongation percentage was also a half
or less of Example 1. When a carpet was pre-pared by using the
crimped yarn and evaluated, although it had more excellent touch
than that of conventional one, glossy texture was the same as that
of conventional one.
Example 14
[0407] A BCF yarn was obtained in the same way as Example 1 except
changing the set temperature at 2 DR to 110.degree. C. Spinnability
of Example 14 was stable as that of Example 1. In the obtained
fiber, crimp elongation percentage was 2.5%, i.e., crimp
development was weak. The boiling water shrinkage was high as
11.1%, i.e., Example 1 was better in dimensional stability than
this example. When a carpet was prepared by using the crimped yarn
and evaluated, it was found that both of touch and glossy texture
were same level as those of conventional one.
Example 15
[0408] A BCF yarn was obtained in the same way as Example 13 except
changing the spinneret to a spinneret with circular holes of
diameter 0.62 mm and depth of hole 1.0 mm. Spinnability of Example
15 was extremely stable as that of Example 1. Cross-section of the
obtained fiber was approximately perfect circle (non-circularity
1.0), and when cross-section was observed by TEM, a uniformly
dispersed sea/island structure was formed, and exposed area ratio
of polylactic acid with respect to fiber surface area was 1.7%.
Island domain size in diameter equivalent was 0.03 to 0.3 .mu.m,
i.e., the same level as Example 1. When a carpet was prepared by
using the crimped yarn and evaluated, although it had an excellent
touch similar to that of Example 1, but as to glossy texture,
Example 1 was better than this example.
Example 16
[0409] A BCF yarn was obtained in the same way as Example 1 except
subjecting hot compressed air treatment by an air jet stuffer
machine at nozzle temperature 150.degree. C. In the crimped yarn,
crimp elongation percentage was low as 2.7%, i.e., crimp
development was weak. When a carpet was prepared by using the
crimped yarn and evaluated, it was found that although glossy
texture was excellent, it had somewhat hard and coarse touch.
TABLE-US-00004 TABLE 3 Example Example Example Example Example
Example 11 12 13 14 15 16 Component A PLLA PLLA PLLA PLLA PLLA PLLA
Weight average molecular weight 23.30,000 23.30,000 23.30,000
23.30,000 23.30,000 23.30,000 Melting point (.degree. C.) 177 177
177 177 177 177 Amount of residual lactide (wt %) 0.12 0.12 0.12
0.12 0.12 0.12 Melt viscosity (Pa s) 225 225 225 225 225 225
Component B N6 N6 N6 N6 N6 N6 Relative viscosity (or inherent
viscosity) 2.15 2.15 2.15 2.15 2.15 2.15 Melting point (.degree.
C.) 225 225 225 225 225 225 Heat of crystal fusion (J/g) 78 78 78
78 78 78 Melt viscosity (Pa s) 58 58 58 58 58 58 Blend ratio
(component A/component B, %) 30/70 30/70 30/70 30/70 30/70 30/70
Melt viscosity ratio (.eta.b/.eta.a) 0.26 0.26 0.26 0.26 0.26 0.26
Physical properties of fiber Island component PLLA PLLA PLLA PLLA
PLLA PLLA Sea component N6 N6 N6 N6 N6 N6 Exposed area ratio (%) of
Component A 1.6 1.5 1.5 1.5 1.7 1.5 Domain size of the island
component (.mu.m) 0.05 to 0.7 0.04 to 0.4 0.03 to 0.3 0.03 to 0.3
0.03 to 0.3 0.03 to 0.3 Width of grooves of fiber surface layer
(.mu.m) 0.33 0.33 -- -- 0.25 0.18 Aspect ratio of groove of fiber
surface layer 18 17 -- -- 21 24 Number of grooves of fiber surface
layer 6 6 -- -- 9 4 (grooves) Carboxyl terminal concentration
(eq/ton) 18 20 18 18 18 18 Non-circularity of fiber cross-section
2.4 2.2 2.5 2.5 1.0 2.5 Fiber thickness (dtex) 1500 1500 1500 1500
1500 1500 Strength (cN/dtex) 1.3 1.8 2.9 3.2 2.8 2.8 Elongation (%)
38 89 48 50 49 48 U % (%) 3.3 1.6 0.7 0.6 0.5 0.8 Boiling water
shrinkage (%) 2.7 1.7 8.5 11.1 2.5 4.7 Abrasion resistance (number
of yarn break) 36 72 108 118 106 128 Crimp elongation percentage
(%) 8 5 4.5 2.5 9 2.7 Elongation percentage under load (%) 2.5 1.5
1.5 1 3 1 Physical properties of fiber structure Abrasion loss
ratio of carpet (%) 46.8 41.1 33.8 32.2 30.5 33.4 Touch of carpet
(softness) .DELTA. .largecircle. .largecircle. .DELTA.
.circleincircle. .DELTA. Appearance of carpet (glossy texture)
.largecircle. .largecircle. .DELTA. .DELTA. .largecircle.
.largecircle.
Example 17
[0410] A BCF yarn was obtained in the same way as Example 1 except
dry blending 1 wt % (0.3 wt % to whole fiber) of talc "SG-2000"
(average particle diameter D50: 0.98 .mu.m, particle of 10 .mu.m or
more: 0 vol %) produced by Nippon Talc Co. to the polylactic acid
P1 (component A). Spinnability in Example 17 was extremely stable
as that of Example 1. The crimped yarn showed an elongation
percentage under load which was 1.4 times of that of Example 1, and
crimp fastness was high.
Example 18
[0411] A BCF yarn was obtained in the same way as Example 1 except
dry blending 1 wt % (0.3 wt % to whole fiber) of melamine cyanurate
"MC-600" (average particle diameter 1.6 .mu.m, particle of 10 .mu.m
or more: 0 vol %) produced by Nissan Chemical Industries, Ltd. to
the polylactic acid P1 (component A). Spinnability in Example 18
was extremely stable as that of Example 1. The crimped yarn showed
an elongation percentage under load which was approximately 1.8
times of that of Example 1, and crimp fastness was extremely
high.
Example 19
[0412] A BCF yarn was obtained in the same way as Example 1 except
dry blending respectively 0.03 wt % of copper iodide and potassium
iodide to nylon 6 (component B) (0.021 wt % to whole fiber,
respectively).
[0413] Furthermore, the crimped yarn obtained in Example 1 and the
crimped yarn obtained in Example 19 were taken as hanks, and
subjected to a light resistance test by using UV Autofade-meter
(type: U48AU) produced by Suga Test Instrument Co. Strength
retentions were determined from strengths of before and after the
light resistance test under the following condition. As a result,
as compared to the strength retention of crimped yarn of Example 1
of 5%, strength retention of crimped yarn of Example 19 was 91%,
i.e., which was a crimped yarn extremely excellent in light
resistance.
[0414] <UV Treatment Condition> [0415] UV irradiation time:
100 hrs [0416] Black panel temperature: 83.degree. C. [0417] In-can
temperature: 64.+-.3.degree. C. [0418] In-can humidity: relative
humidity 50.+-.5% at in-can temperature
[0418] Strength retention (%)=strength (cN/dtex) after UV
treatment/strength (cN/dtex) before UV treatment.times.100
TABLE-US-00005 TABLE 4 Example 17 Example 18 Example 19 Component A
PLLA PLLA PLLA Weight average molecular weight 23.30,000 23.30,000
23.30,000 Melting point (.degree. C.) 177 177 177 Amount of
residual lactide (wt %) 0.12 0.12 0.12 Melt viscosity (Pa s) 225
225 225 Crystal nucleating agent talc melamine -- cyanurate Adding
amount of nucleating agent (wt %) 1 1 -- Component B N6 N6 N6
Relative viscosity (or inherent viscosity) 2.15 2.15 2.15 Melting
point (.degree. C.) 225 225 225 Heat of crystal fusion (J/g) 78 78
78 Melt viscosity (Pa s) 58 58 58 Light stabilizer -- -- CuI/KI
Adding amount of Light stabilizer (wt %) -- -- 0.03/0.03 Blend
ratio (component A/component B, %) 30/70 30/70 30/70 Melt viscosity
ratio (.eta.b/.eta.a) 0.26 0.26 0.26 Physical properties of fiber
Island component PLLA PLLA PLLA Sea component N6 N6 N6 Exposed area
ratio (%) of Component A 1.6 1.6 1.5 Domain size of the island
component (.mu.m) 0.03 to 0.3 0.03 to 0.3 0.03 to 0.3 Width of
grooves of fiber surface layer (.mu.m) 0.26 0.25 0.26 Aspect ratio
of groove of fiber surface layer 19 18 20 Number of grooves of
fiber surface layer (grooves) 8 8 7 Carboxyl terminal concentration
(eq/ton) 18 18 18 Non-circularity of fiber cross-section 2.5 2.5
2.5 Fiber thickness (dtex) 1500 1500 1500 Strength (cN/dtex) 2.7
2.7 2.7 Elongation (%) 45 46 47 U % (%) 0.9 0.8 0.8 Boiling water
shrinkage (%) 2.5 2.2 2.7 Abrasion resistance (number of yarn
break) 102 105 100 Crimp elongation percentage (%) 13 14 12
Elongation percentage under load (%) 5 6.3 3.5 Physical properties
of fiber structure Abrasion loss ratio of carpet (%) 23.2 22.1 26.0
Touch of carpet (softness) .circleincircle. .circleincircle.
.circleincircle. Appearance of carpet (glossy texture)
.circleincircle. .circleincircle. .circleincircle.
Example 20
[0419] For core component and sheath component respectively, by
using continuous spinning, stretching and crimping machine equipped
with a single screw kneading machine shown in FIG. 9, a BCF yarn
was obtained by continuously carrying out melt spinning,
stretching, heat treatment and crimping treatment.
[0420] To the core component hopper 21 shown in FIG. 9, the
component A (P4) was fed, and to the sheath component hopper 22,
the component B (N6-1 melting point 225.degree. C., heat capacity
of melting point peak 79 J/g, relative viscosity 2.59 and melt
viscosity 150 Pasec.sup.-1) was fed, the component A and the
component B were separately molten and kneaded by the single screw
extruding/kneading machines 23 and 24, respectively, and introduced
into the spinning block 25, respective polymers were metered and
discharged by the gear pumps 26 and 27 to introduce into the
spinning pack 28, and spun from the spinneret 29 having 96 holes of
trilobal cross-section. At this time, numbers of rotation of gear
pumps 26 and 27 for the core component and the sheath component
were selected such that sheath/core ratio=60/40 (weight ratio). The
yarn 31 was cooled and solidified by the uniflow cooling apparatus
30 and oiled by the oiling device 32. Furthermore, after taking up
by the first roll 33, the unstretched yarn was stretched by setting
a speed of the second roll 34 to a speed of 1.02 times of the speed
of the first roll 33 and then, stretched by a speed ratio of the
second roll 34 and the third roll 35, heat treated by the third
roll 35, stretched again by a speed ratio of the third roll 35 and
the fourth roll 36, heat treated again by the fourth roll 36,
imparted an air stuffer crimp by the crimping nozzle 37 which uses
a hot fluid while the yarn was relaxed (overfeed) between the
fourth roll 36 and the cooling roll (cooling drum) 38, fixed its
structure by cooling the crimped yarn on surface of the cooling
roll (cooling drum) 38, imparted a tension between the sixth roll
39 and the seventh roll 40 such that the crimp was not extended
(0.08 cN/dtex, fiber thickness of wound crimped yarn was employed
as the fiber thickness), interlaced by the interlacing nozzle 47
between the seventh roll 40 and the winder 42, and wound under a
tension which did not extend the crimp (0.08 cN/dtex, fiber
thickness of wound crimped yarn was employed as the fiber
thickness) to obtain a BCF yarn (cheese package 41) of 1920 dtex 96
filaments which was subjected to spinning, stretching, heat
treatment and crimp treatment in one step. Approximately 100 kg was
sampled but yarn break, single fiber break or the like did not
occur and the spinning was extremely stable. The result of Example
20 is shown in Table 5.
[0421] The melt spinning, stretching, heat treatment and crimp
treatment conditions are as follows: [0422] Kneading machine
temperature: 230.degree. C. [0423] Spinning temperature:
245.degree. C. [0424] Filtering layer: filled with 30# morundum
sand [0425] Filter: 20 .mu.m nonwoven fabric filter [0426]
Spinneret 2 (spinneret just before polymer discharge): slit width
0.15 mm, slit length 1.5 mm and number of holes 96 [0427] Spinneret
1 (spinneret of schematic view 45 of FIG. 12. Positioned just
before spinneret 2 having separate flow channels for core component
and sheath component) [0428] Sheath component; hole diameter 0.5
mm, spinning hole length 0.5 mm and number of holes per one
filament 3 [0429] Core component; slit width 0.12 mm, slit length
1.2 mm and number of holes per one filament 1 [0430] Out put: 498.6
g/min (1 pack 1 yarn, 96 filaments) [0431] Cooling: uniflow of
cooling length 1 m was used. cooling air temperature 20.degree. C.,
wind speed 0.5 m/sec, cooling starting position was 0.1 m beneath
spinneret surface [0432] Oiling agent: 10% concentration emulsion
oiling agent of aliphatic acid ester was deposited to by 10% per
yarn [0433] First roll temperature: 25.degree. C. [0434] Second
roll temperature: 70.degree. C. [0435] Third roll temperature:
135.degree. C. [0436] Fourth roll temperature: 190.degree. C.
[0437] Cooling roll temperature: 25.degree. C. [0438] Sixth roll
temperature: 25.degree. C. [0439] Seventh roll temperature:
25.degree. C. [0440] Heated steam treatment temperature:
230.degree. C. [0441] First roll speed: 840 m/min (=second roll
speed/1.02) [0442] Second roll speed: 857 m/min [0443] Third roll
speed: 2400 m/min [0444] Fourth roll speed: 3000 m/min [0445]
Cooling roll speed: 80 m/min [0446] Sixth roll speed: 2550 m/min
[0447] Seventh roll speed: 2600 m/min [0448] Winding speed: 2550
m/min [0449] Total stretching ratio: 3.5 times (second to third
roll: 2.8 times, third to fourth roll: 1.25 times). [0450]
Compressed air for interlacing: 0.2 MPa
[0451] The obtained BCF yarn had a crimp configuration in which
single fibers were folded in random direction in loop-like state
and the single fibers entangle with each other. Strength was 2.3
cN/dtex, boiling water shrinkage was 2.2%, and single fiber
thickness was 20 dtex. In addition, it showed excellent crimp
characteristics such that crimp elongation percentage was 25% and
elongation percentage under load was 13% and it was a crimped yarn
of which crimp is durable. When a circular knit and a carpet were
prepared by using the crimped yarn, both had voluminous feeling and
soft touch and exhibited an aesthetic glossiness and excellent in
texture.
[0452] Regarding a circular knit fabric of the obtained crimped
yarn, as a result of evaluating peeling resistance, there was no
appearance change, and it showed an excellent peeling resistance.
As a result of abrasion resistance test of a carpet in which the
obtained crimped yarn was used, it had an excellent abrasion
resistance as abrasion loss ratio 10%, and as to the carpet fabric
after the abrasion, whitening of the crimped yarn and a splitting
of sheath was not observed.
[0453] As a result of observation by TEM of a cross-section of
single fiber of the obtained crimped yarn, core component
positioned at center of the single fiber, minimum value of
thickness of the sheath component was 3.0 .mu.m, and all core
component was covered by the sheath component. That is, exposed
area ratio of polylactic acid with respect to fiber surface area
was 0%. The non-circularity of single fiber was 3.0 and
non-circularity of core component was 3.0. The melting points of
the obtained crimped yarn in DSC were 169.degree. C. (peak based on
the component A) and 224.degree. C. (peak based on the component
B), i.e., melting peaks based on each component were observed, and
total heat capacity of respective melting peaks was 72 J/g, i.e., a
sufficient crystallinity was exhibited.
Comparative Example 6
[0454] It is tried to obtain a BCF yarn comprising only the
component A in the same condition as Example 20 except, in Example
20, without using the component B and changing the spinneret, but
at the fourth roll 36 and the crimping nozzle 37, thermal bond
between single fibers was serious and spinning was impossible.
Therefore, by changing the temperature of the third roll 35, the
temperature of the fourth roll 36 and the temperature of the
crimping nozzle 37, crimped yarn of Comparative example 6 was
obtained (at this time, the speed of the sixth roll 39, the speed
of the seventh roll 40 and the winding speed were changed such that
the tension would be in the range indicated in Example 20. In
addition, the out put was controlled such that the single fiber
thickness would be 20 dtex). The spinnability was bad and yarn
break occurred 15 times in 100 kg sampling. The result of
Comparative example 6 is shown in Table 5, and specification of the
spinneret, temperature of the third roll 35, temperature of the
fourth roll 36, temperature of the crimping nozzle 37, speed of the
sixth roll 39, speed of the seventh roll 40 and winding speed of
Comparative example 6 are shown in the following: [0455] Spinneret
2 of Comparative example 6: core component slit width 0.12 mm, slit
length 1.2 mm and number of holes per one filament 1 (no flow
channel for sheath component) [0456] Third roll temperature of
Comparative example 6: 90.degree. C. [0457] Fourth roll temperature
of Comparative example 6: 110.degree. C. [0458] Crimp nozzle
temperature of Comparative example 6: 150.degree. C. [0459] Sixth
roll speed: 2650 m/min [0460] Seventh roll speed: 2660 m/min [0461]
Winding speed of Comparative example 6: 2670 m/min
[0462] From Example 20 and Comparative example 6, it is found that
the crimped yarn becomes a crimped yarn excellent in abrasion
resistance and crimp characteristics by having a sheath component.
In peeling resistance test of Comparative example 6, since it has
not a sheath component, a peeling of sheath/core interface was not
observed, but a few weaving or fibrillation of crimped yarn was
observed and void portions were observed in all tests. In addition,
in the crimped yarn of Comparative example 6, a few thermally
bonded portion was observed, strength was low as 1.2 cN/dtex and
yarn break occurred frequently in a process of preparing a circular
knit fabric or a carpet. In addition, since highly oriented
molecular chains were left in the crimped yarn and the boiling
water shrinkage was high as 10%, the peeling resistance, abrasion
resistance, crimp characteristics of the crimped yarn deteriorated
with the lapse of time.
Examples 21 to 22, Comparative examples 7 and 8
[0463] Crimped yarns of Examples 21 to 22 and Comparative examples
7 and 8 were obtained in the same way as Example 20 except
changing, in Example 20, temperature of fourth roll 36 (at this
time, at this time, the speed of sixth roll 39, the speed of the
seventh roll 40 and the winding speed were controlled such that the
tension would be that indicated in Example 20). In Examples 21 and
22, although they were not a level which causes a trouble, yarn
break occurred one times, respectively. Spinnabilities of
Comparative examples 7 and 8 were bad and respective yarn breaks
were, in Comparative example 7, 11 times and in Comparative example
8, 13 times. Results of Examples 21 to 22 and Comparative examples
7 and 8 are shown in Table 5. The spinning conditions of Examples
21 to 22 and Comparative examples 7 and 8 are described below:
[0464] Fourth roll temperature [0465] Example 21: 160.degree. C.
[0466] Example 22: 220.degree. C. [0467] Comparative example 7:
150.degree. C. [0468] Comparative example 8: 225.degree. C.
[0469] As can be understood by comparing Examples 20 to 22 and
Comparative examples 7 and 8, by employing heat treatment
temperature 160 to 220.degree. C. of the final roll after
stretching, a crimped yarn having a preferable strength and boiling
water shrinkage, i.e., a crimped yarn excellent in peeling
resistance can be obtained in high productivity. It is understood
that this is because, by employing the above-mentioned preferable
production condition, effect of partially melting the core
component on the final roll after stretching and effect that the
fiber becomes in a high temperature condition immediately in the
crimp nozzle function synergistically and, without being affected
by the difference of heat shrinking characteristics between the
core component and the sheath component, 2 phase structure of a
crystal phase and a random amorphous phase could be formed in the
core component and the sheath component. In the crimped yarn of
Comparative example 8, the sheath component partially melted by the
heat treatment on the final roll, and an irregularity arose in
cross-sectional shape to render a portion of the sheath component
thin.
[0470] Furthermore, as can be understood by comparing Examples 20
to 22, by employing the more preferable production method, it
became a crimped yarn excellent also in crimp characteristics.
Therefore, a circular knit fabric and a carpet comprising the
crimped yarn of Example 20 exhibited an excellent texture compared
to those of Examples 21 to 22.
TABLE-US-00006 TABLE 5 Com- Com- Comparative parative parative Item
Example 20 example 6 Example 21 Example 22 example 7 example 8
Component A -- P4 P4 P4 P4 P4 P4 Melting point of Component A (Tma)
.degree. C. 170 170 170 170 170 170 Melt viscosity of Component A
(.eta.a) Pa sec.sup.-1 200 200 200 200 200 200 Component B -- N6-1
-- N6-1 N6-1 N6-1 N6-1 Melting point of Component B (Tmb) .degree.
C. 225 -- 225 225 225 225 Melt viscosity of Component B (.eta.b) Pa
sec.sup.-1 150 -- 150 150 150 150 Melt viscosity -- 0.75 -- 0.75
0.75 0.75 0.75 ratio of the component A and the component B
(.eta.b/.eta.a) Sheath/core ratio (core component/sheath component)
-- 40/60 100/0 40/60 40/60 40/60 40/60 Content of the component A
wt % 40 100 40 40 40 40 Linear discharge velocity m/min 7.3 7.3 7.5
6.9 7.7 6.7 Spinning temperature .degree. C. 245 245 245 245 245
245 Total stretching ratio -- 3.5 3.5 3.5 3.5 3.5 3.5 Second roll
temperature .degree. C. 70 70 70 70 70 70 Third roll temperature
.degree. C. 135 90 135 135 135 135 Fourth roll temperature .degree.
C. 190 110 160 220 150 225 Crimp nozzle temperature .degree. C. 230
150 230 230 230 230 Fourth roll speed m/min 3000 3000 3000 3000
3000 3000 Winding speed m/min 2550 2670 2620 2420 2690 2350
(1-winding speed/fourth roll speed) .times. 100 % 15.0 11.0 12.7
19.3 10.3 21.7 Strength cN/dtex 2.3 1.2 2.9 1.7 3.6 1.3 Elongation
% 45 45 45 45 45 20 Boiling water shrinkage % 2.2 10 5.3 1.7 9.2
1.1 Single fiber thickness dtex 20 20 20 20 20 20 Non-circularity
of single fiber -- 3.0 3.0 3.0 3.0 3.0 3.0 Non-circularity of core
component -- 3.0 3.0 3.0 3.0 3.0 3.0 U % (normal) -- 1.2 2.5 1.3
1.4 2 1.9 Crimp elongation percentage after boiling water % 25 4 8
33 4 36 treatment Crimp elongation percentage under load % 13 1 4
20 2 18 CF value -- 13 13 13 13 13 13 Minimum value of sheath
component thickness .mu.m 3.0 0 3.0 2.0 3.0 0.9 Total heat capacity
of melting peak of fiber J/g 72 46 72 72 72 72 Spinnability
.circleincircle. to X .circleincircle. X .circleincircle.
.circleincircle. .largecircle. X Abrasion loss ratio wt % 10 72 19
19 33 34 Peeling resistance .circleincircle. to X .circleincircle.
X .largecircle. .largecircle. X X 24 5 18 20 10 10 Bulkiness
.circleincircle. to X .circleincircle. X .largecircle.
.circleincircle. X .largecircle. Softness .circleincircle. to X
.circleincircle. X .largecircle. .circleincircle. X .DELTA.
Examples 23 to 24, Comparative Examples 9 to 10
[0471] Crimped yarns of Examples 23 to 24, Comparative example 9 to
10 were obtained in the same way as Example 20 except changing
total stretching ratio in Example 20 (speed of the first to third
rolls were changed to the following ratio and render the speed of
the first roll 33 to a value obtained by dividing the speed of the
second roll 34 by 1.02). In Examples 23 to 24, although they were
not a level which causes a trouble, yarn break occurred one time,
respectively. Spinnability of Comparative examples 9 to 10 were
bad, and yarn breaks were observed in Comparative example 9, 12
times and in Comparative example 10, 14 times. Results of Examples
23 to 24 and Comparative examples 9 to 10 are shown in Table 6.
Spinning conditions of Examples 23 to 24 and Comparative examples 9
to 10 are shown below: [0472] Total stretching ratio [0473] Example
23: 2.1 times (second to third roll: 1.68 times, third to fourth
roll: 1.25 times) [0474] Example 24: 4.9 times (second to third
roll: 3.92 times, third to fourth roll: 1.25 times) [0475]
Comparative example 9: 1.9 times (second to third roll: 1.52 times,
third to fourth roll: 1.25 times) [0476] Comparative example 10:
5.1 times (second to third roll: 4.08 times, third to fourth roll:
1.25 times).
[0477] As can be understood by comparing Examples 20, 23 to 24 and
Comparative examples 9 to 10, by employing total stretching ratio 2
to 5 times, it becomes a crimped yarn, i.e., a crimped yarn
excellent in peeling resistance. By carrying out stretching in the
above-mentioned total stretching ratio, spinning speed can be
suppressed in an appropriate range, and the core component and the
sheath component of the stretched yarn can be uniformly oriented.
Therefore, it is understood that this is because, in the crimp
processing, a difference of heat shrinking characteristics between
the core component and the sheath component is hard to arise- and
an undue strain is not generated in molecular chains neighboring
the sheath/core interface. In Example 20, since it has a more
preferable fiber structure (strength and boiling water shrinkage)
than those of Examples 23 to 24, it is a crimped yarn excellent in
peeling resistance.
TABLE-US-00007 TABLE 6 Comparative Comparative Item Example 23
Example 24 example 9 example 10 Component A -- P4 P4 P4 P4 Melting
point of the component A (Tma) .degree. C. 170 170 170 170 Melt
viscosity of the component A (.eta.a) Pa sec.sup.-1 200 200 200 200
Component B -- N6-1 N6-1 N6-1 N6-1 Melting point of the component B
(Tmb) .degree. C. 225 225 225 225 Melt viscosity of the component B
(.eta.b) Pa sec.sup.-1 150 150 150 150 Melt viscosity ratio of the
component A and the component B -- 0.75 0.75 0.75 0.75
(.eta.b/.eta.a) Sheath/core ratio (core component/sheath component)
-- 40/60 40/60 40/60 40/60 Content of the component A wt % 40 40 40
40 Linear discharge velocity m/min 7.3 7.3 7.3 7.3 Spinning
temperature .degree. C. 245 245 245 245 Total stretching ratio --
2.1 4.9 1.9 5.1 Second roll temperature .degree. C. 70 70 70 70
Third roll temperature .degree. C. 135 135 135 135 Fourth roll
temperature .degree. C. 190 190 190 190 Crimp nozzle temperature
.degree. C. 230 230 230 230 Fourth roll speed m/min 3000 3000 3000
3000 Winding speed m/min 2550 2550 2550 2550 (1-winding
speed/fourth roll speed) .times. 100 % 15.0 15.0 15.0 15.0 Strength
cN/dtex 1.6 3.4 1.3 3.7 Elongation % 55 20 60 15 Boiling water
shrinkage % 1.3 5.4 2 6 Single fiber thickness dtex 20 20 20 20
Non-circularity of single fiber -- 3.0 3.0 3.0 3.0 Non-circularity
of core component -- 3.0 3.0 3.0 3.0 U % (normal) -- 1.5 1.8 2.6
2.5 Crimp elongation percentage after boiling water treatment % 25
25 25 25 Crimp elongation percentage under load % 13 13 6 7 Minimum
value of thickness of sheath component .mu.m 3.0 3.0 3.0 3.0 CF
value -- 13 13 13 13 Total heat capacity of melting peak of fiber
J/g 72 72 72 72 Spinnability .circleincircle. to X .circleincircle.
.circleincircle. X X Abrasion loss ratio wt % 13 14 36 34 Peeling
resistance .circleincircle. to X .largecircle. .largecircle. X X 20
18 9 9 Bulkiness .circleincircle. to X .circleincircle.
.circleincircle. .largecircle. .largecircle. Softness
.circleincircle. to X .circleincircle. .circleincircle. .DELTA.
.DELTA.
Examples 25 to 27, Comparative Examples 11 and 12
[0478] Crimped yarns of Examples 25 to 27 and Comparative examples
11 and 12 were obtained in the same way as Example 20 except
changing the number of holes of spinneret in Example 20. Although
it was not a level which causes a trouble, yarn break occurred one
time in both of Examples 25 and Example 26. Spinnabilities were not
good in Comparative examples 11 and 12, and yarn breaks occurred in
Comparative example 11, 11 times and in Comparative example 12, 12
times. Results of Examples 25 to 27 and Comparative examples 11 and
12 are shown in Table 7. Spinning conditions of Examples 25 to 27
and Comparative examples 11 and 12 are shown below: [0479] Number
of holes of spinneret [0480] Example 25: 320 [0481] Example 26: 72
[0482] Example 27: 50 [0483] Comparative example 11: 480 [0484]
Comparative example 12: 45.
[0485] As can be understood by comparing Examples 20, 25 to 27 and
Comparative examples 11 and 12, by making to a crimped yarn of the
preferable single fiber thickness, it becomes a crimped yarn
excellent in peeling resistance. It is understood that this is
because, by making single fiber thickness to 40 dtex or less, the
core component and the sheath component are quickly heated in the
crimp processing step, without giving an undue strain to the
sheath/core interface, and 2 phase structure of a crystal phase and
a random amorphous phase could be formed. By making the single
fiber thickness to 5 dtex or more, it is possible to avoid an
adverse effect that the crimped yarn was extended by a tension
loaded to the yarn and generated a strain in the sheath/core
interface, and the peeling resistance could be improved. By
comparing circular knit fabrics or carpets comprising only crimped
yarn of Examples 25, and 27, a circular knit fabric or a carpet
comprising the crimped yarn of Example 20 was excellent in
voluminous texture and the voluminous texture was able to be
maintained for a long time. That is, by making to a crimped yarn of
single fiber thickness 5 to 40 dtex, it became a crimped yarn of
which crimp fastness was also high.
TABLE-US-00008 TABLE 7 Example Comparative Comparative Item 25
Example 26 Example 27 example 11 example 12 Component A -- P4 P4 P4
P4 P4 Melting point of Component A (Tma) .degree. C. 170 170 170
170 170 Melt viscosity of Component A (.eta.a) Pa sec.sup.-1 200
200 200 200 200 Component B -- N6-1 N6-1 N6-1 N6-1 N6-1 Melting
point of Component B (Tmb) .degree. C. 225 225 225 225 225 Melt
viscosity of Component B (.eta.b) Pa sec.sup.-1 150 150 150 150 150
Melt viscosity ratio of the component A and the -- 0.75 0.75 0.75
0.75 0.75 component B (.eta.b/.eta.a) Sheath/core ratio (core
component/sheath component) -- 40/60 40/60 40/60 40/60 40/60
Content of the component A wt % 40 40 40 40 40 Linear discharge
velocity m/min 2.2 9.8 14.1 1.5 15.6 Spinning temperature .degree.
C. 245 245 245 245 245 Total stretching ratio -- 3.5 3.5 3.5 3.5
3.5 Second roll temperature .degree. C. 70 70 70 70 70 Third roll
temperature .degree. C. 135 135 135 135 135 Fourth roll temperature
.degree. C. 190 190 190 190 190 Crimp nozzle temperature .degree.
C. 230 230 230 230 230 Fourth roll speed m/min 3000 3000 3000 3000
3000 Winding speed m/min 2550 2550 2550 2550 2550 (1-winding
speed/fourth roll speed) .times. 100 % 15.0 15.0 15.0 15.0 15.0
Strength cN/dtex 2.2 2.1 2.2 1.7 2.5 Elongation % 45 45 45 45 45
Boiling water shrinkage % 5.1 4.4 4.8 8.3 9.1 Single fiber
thickness dtex 6 26.7 38.4 4 42.7 Non-circularity of single fiber
-- 3.0 3.0 3.0 3.0 3.0 Non-circularity of core component -- 3.0 3.0
3.0 3.0 3.0 U % (normal) -- 1.4 1.4 1.4 8.3 8.1 crimp elongation
percentage after boiling water treatment % 20 25 22 14 20 Crimp
elongation percentage under load % 7 9 6 2 4 Minimum value of
thickness of sheath component .mu.m 1.6 3.4 9.1 1.3 9.4 CF value --
13 13 13 13 13 Total heat capacity of melting peak of fiber J/g 70
70 69 68 62 Spinnability .circleincircle. to X .largecircle.
.largecircle. .largecircle. X X Abrasion loss ratio wt % 19 13 18
32 35 Peeling resistance .circleincircle. to X .largecircle.
.largecircle. .largecircle. X X 16 20 17 8 9 Bulkiness
.circleincircle. to X .largecircle. .largecircle. .largecircle.
.DELTA. .largecircle. Softness .circleincircle. to X .largecircle.
.largecircle. .DELTA. .largecircle. X
Examples 28 to 31
[0486] Crimped yarns of Examples 28 to 31 were obtained in the same
way as Example 20 except changing, in Example 20, the resins used
as the component A and the component B. A yarn break was not
confirmed in Examples 28, 29. In Examples 30 and 31, although it
was not a level which causes a trouble, yarn break occurred one
time, respectively. Results of Examples 28 to 29 are shown in Table
8. The resins used in Examples 28 to 31 were described below:
[0487] Resins used as core component and sheath component [0488]
Example 28: component A=P4, component B=N6-2 (melting point
225.degree. C., heat capacity of melting point peak 77 J/g,
relative viscosity 2.95, melt viscosity 300 Pasec.sup.-1) [0489]
Example 29: component A=P4, component B=N6-3 (melting point
225.degree. C., heat capacity of melting point peak 78 J/g,
relative viscosity 2.10, melt viscosity 50 Pasec.sup.-1) [0490]
Example 30: component A=P5, component B=N6-3 [0491] Example 31:
component A=P6, component B=N.sup.6-2.
[0492] As can be understood by comparing Examples 20, 28 to 31, it
is found that, by making the melt viscosity ratio of the component
A and the component B to the preferable range, crimped yarns
excellent in peeling resistance were obtained. It is understood
that this is because, by making to a preferable melt viscosity
ratio, it becomes possible to make stresses to the core component
and the sheath component uniform in melt spinning step, and since
almost no difference of molecular orientation between the core
component and the sheath component of the unstretched yarn was
generated, it was possible that the core component and the sheath
component were uniformly oriented in the stretching step,
difference of heat shrinking characteristics of the respective
component in crimp processing became small and molecular chains
neighboring the sheath/core interface was hardly be affected with
an undue strain.
[0493] Furthermore, compared to circular knit fabrics or carpets
comprising the crimped yarn of Examples 28 to 31, a circular knit
fabric or a carpet comprising the crimped yarn of Example 20 was
excellent in peeling resistance. Even when the sheath is
fibrillated, the core component is hardly exposed, and it is found
that the abrasion resistance was excellent.
TABLE-US-00009 TABLE 8 Item Example 28 Example 29 Example 30
Example 31 Component A -- P4 P4 P5 P6 Melting point of the
component A (Tma) .degree. C. 170 170 170 170 Melt viscosity of the
component A (.eta.a) Pa sec.sup.-1 200 200 300 120 Component B --
N6-2 N6-3 N6-3 N6-2 Melting point of the component B (Tmb) .degree.
C. 225 225 225 225 Melt viscosity of the component B (.eta.b) Pa
sec.sup.-1 300 50 50 300 Ratio of melt viscosity of the component A
and the component -- 1.50 0.25 0.17 2.50 B (.eta.b/.eta.a)
Sheath/core ratio (core component/sheath component) -- 40/60 40/60
40/60 40/60 Content of the component A wt % 40 40 40 40 Linear
discharge velocity m/min 7.3 7.3 7.3 7.3 Spinning temperature
.degree. C. 245 245 245 245 Total stretching ratio -- 3.5 3.5 3.5
3.5 Second roll temperature .degree. C. 70 70 70 70 Third roll
temperature .degree. C. 135 135 135 135 Fourth roll temperature
.degree. C. 190 190 190 190 Crimp nozzle temperature .degree. C.
230 230 230 230 Fourth roll speed m/min 3000 3000 3000 3000 Winding
speed m/min 2550 2550 2550 2550 (1-winding speed/fourth roll speed)
.times. 100 % 15.0 15.0 15.0 15.0 Strength cN/dtex 3.2 1.6 1.6 3.2
Elongation % 45 45 45 45 Boiling water shrinkage % 4.6 4.8 5.6 5.8
Single fiber thickness dtex 20 20 20 20 Non-circularity of single
fiber -- 3.0 3.0 3.0 3.0 Non-circularity of core component -- 3.0
3.0 3.0 3.0 U % (normal) -- 1.2 1.2 1.2 1.2 Crimp elongation
percentage after boiling water treatment % 25 25 25 25 Crimp
elongation percentage under load % 11 9 9 3 Minimum value of
thickness of sheath component .mu.m 2.7 3.0 2.3 0.3 CF value -- 13
13 13 13 Total heat capacity of melting peak of fiber J/g 74 70 72
70 Spinnability .circleincircle. to X .circleincircle.
.circleincircle. .largecircle. .largecircle. Abrasion loss ratio wt
% 15 17 24 26 Peeling resistance .circleincircle. to X
.largecircle. .largecircle. .DELTA. .DELTA. 21 18 15 15 Bulkiness
.circleincircle. to X .circleincircle. .largecircle. .largecircle.
.DELTA. Softness .circleincircle. to X .circleincircle.
.largecircle. .DELTA. .DELTA.
Examples 32 to 36
[0494] Crimped yarns of Examples 32 to 36 were obtained in the same
way as Example 20 except changing the sheath/core ratio (weight
ratio) in Example 20. Results of Examples 32 to 36 are shown in
Table 5, and the respective sheath/core ratios are shown in the
following: [0495] Example 32: core component/sheath component=20/80
[0496] Example 33: core component/sheath component=30/70 [0497]
Example 34: core component/sheath component=60/40 [0498] Example
35: core component/sheath component=70/30 [0499] Example 36: core
component/sheath component=80/20.
[0500] As can be understood from Examples 20 and 32 to 36, it is
possible to obtain crimped yarns of which peeling resistances are
more excellent, by employing sheath/core ratios considered to be
preferable. It is understood that this is because, by employing the
preferable sheath/core ratio, an area of the sheath/core interface
per a unit volume of the core component becomes large. Since it is
possible to prevent a peeling of the sheath/core interface, the
core component is not exposed to be shaved when abraded, and it
became a crimped yarn more excellent in abrasion resistance.
Further, the crimped yarn of Example 20, compared to those of
Examples 32 to 36, was a crimped yarn having a crimp of which
peeling resistance and fastness were high and of which bulkiness
and softness could be maintained for a long time.
TABLE-US-00010 TABLE 9 Example Example Item 32 33 Example 34
Example 35 Example 36 Component A -- P4 P4 P4 P4 P4 Melting point
of the component A (Tma) .degree. C. 170 170 170 170 170 Melt
viscosity of the component A (.eta.a) Pa sec.sup.-1 200 200 200 200
200 Component B -- N6-1 N6-1 N6-1 N6-1 N6-1 Melting point of the
component B (Tmb) .degree. C. 225 225 225 225 225 Melt viscosity of
the component B (.eta.b) Pa sec.sup.-1 150 150 150 150 150 Melt
viscosity ratio of the component A and the component -- 0.75 0.75
0.75 0.75 0.75 B (.eta.b/.eta.a) Sheath/core ratio (core
component/sheath component) -- 20/80 30/70 60/40 70/30 80/20
Content of the component A wt % 20 30 60 70 80 Linear discharge
velocity m/min 7.4 7.4 7.2 7.2 7.1 Spinning temperature .degree. C.
245 245 245 245 245 Total stretching ratio -- 3.5 3.5 3.5 3.5 3.5
Second roll temperature .degree. C. 70 70 70 70 70 Third roll
temperature .degree. C. 135 135 135 135 135 Fourth roll temperature
.degree. C. 190 190 190 190 190 Crimp nozzle temperature .degree.
C. 230 230 230 230 230 Fourth roll speed m/min 3000 3000 3000 3000
3000 Winding speed m/min 2550 2550 2550 2550 2550 (1-winding
speed/fourth roll speed) .times. 100 % 15.0 15.0 15.0 15.0 15.0
Strength cN/dtex 2.4 2.3 2 1.8 1.6 Elongation % 45 45 45 45 45
Boiling water shrinkage % 2.1 2.1 2.8 4.8 5.5 Single fiber
thickness dtex 20 20 20 20 20 Non-circularity of single fiber --
3.0 3.0 3.0 3.0 3.0 Non-circularity of core component -- 3.0 3.0
3.0 3.0 3.0 U % (normal) -- 1.1 1.1 1.4 1.3 1.3 Crimp elongation
percentage after boiling water treatment % 25 25 25 25 25 Crimp
elongation percentage under load % 14 14 10 6 4 Minimum value of
thickness of sheath component .mu.m 4.4 3.8 1.8 1.3 0.9 CF value --
13 13 13 13 13 Total heat capacity of melting peak of fiber J/g 77
75 62 58 51 Spinnability .circleincircle. to X .circleincircle.
.circleincircle. .circleincircle. .circleincircle. .largecircle.
Abrasion loss ratio wt % 9 9 13 20 28 Peeling resistance
.circleincircle. to X .circleincircle. .circleincircle.
.circleincircle. .largecircle. .DELTA. 25 24 23 20 14 Bulkiness
.circleincircle. to X .circleincircle. .circleincircle.
.circleincircle. .largecircle. .DELTA. Softness .circleincircle. to
X .circleincircle. .circleincircle. .circleincircle. .DELTA.
.DELTA.
Examples 37 to 41
[0501] BCF yarns of Examples 36 to 41 were obtained in the same way
as Example 20 except changing the non-circularity of single fiber
and the non-circularity of core component in Example 20 by changing
the spinneret. Results of Examples 37 to 41 are shown in Table 10
and the respective spinneret specifications are shown in the
following: [0502] Spinneret 2 of Example 37: slit width 0.3 mm,
slit length 1.5 mm and number of holes 96 [0503] Spinneret 1 of
Example 37: [0504] Sheath component; hole diameter 0.5 mm, spinning
hole length 0.5 mm and number of holes per one filament 3 [0505]
Core component; slit width 0.12 mm, slit length 0.6 mm and number
of holes per one filament 1 [0506] Spinneret 2 Example 38: slit
width 0.15 mm, slit length 2.25 mm and number of holes 96 [0507]
Spinneret 1 of Example 38: [0508] Sheath component; hole diameter
0.5 mm, spinning hole length 0.5 mm and number of holes per one
filament 3 [0509] Core component; slit width 0.12 mm, slit length
1.8 mm and number of holes per one filament 1 [0510] Spinneret 2 of
Example 39: slit width 0.25 mm, slit length 0.75 mm and number of
holes 96 [0511] Spinneret 1 of Example 39: [0512] Sheath component;
hole diameter 0.5 mm, spinning hole length 0.5 mm and number of
holes per one filament 3 [0513] Core component; slit width 0.12 mm,
slit length 0.48 mm and number of holes per one filament 1 [0514]
Spinneret 2 of Example 40: slit width 0.15 mm, slit length 2.70 mm
and number of holes 96 [0515] Spinneret 1 of Example 40: [0516]
Sheath component; hole diameter 0.5 mm, spinning hole length 0.5 mm
and number of holes per one filament 3 [0517] Core component; slit
width 0.12 mm, slit length 2.16 mm and number of holes per one
filament 1. [0518] Spinneret 2 of Example 41: spinneret hole
diameter 0.6 mm, spinning hole length 0.6 mm and number of holes 96
[0519] Spinneret 1 of Example 41: [0520] Sheath component; hole
diameter 0.5 mm, spinning hole length 0.5 mm and number of holes
per one filament 3 [0521] Core component; hole diameter 0.6 mm,
spinning hole length 0.6 mm and number of holes per one filament
1.
[0522] As can be understood from Examples 20 and 37 to 41, it is
found that, by being the non-circularity of single fiber high, the
single fiber is easily uniformly heated in the crimp nozzle, a
polarization becomes likely to occur in both components of the core
component and the sheath component between a crystal phase and a
random amorphous phase, in addition, the adhered area of the core
component and the sheath component also becomes large and a crimped
yarn excellent in peeling resistance is obtained.
[0523] However, compared to those of Examples 38 and 40, crimped
yarns of Examples 20, 37, 39 and 41 were more excellent in abrasion
resistance. That is, by making the non-circularity of single fiber
into the preferable range, it became easy to uniformly cover with
the sheath component (minimum value of thickness of sheath
component is large), and since the cross-section of single fiber
had not an excessively acute angle, a crimped yarn excellent in
peeling resistance and abrasion resistance was obtained.
TABLE-US-00011 TABLE 10 Example Example Item 37 38 Example 39
Example 40 Example 41 Component A -- P4 P4 P4 P4 P4 Melting point
of the component A (Tma) .degree. C. 170 170 170 170 170 Melt
viscosity of the component A (.eta.a) Pa sec.sup.-1 200 200 200 200
200 Component B -- N6-1 N6-1 N6-1 N6-1 N6-1 Melting point of the
component B (Tmb) .degree. C. 225 225 225 225 225 Melt viscosity of
the component B (.eta.b) Pa sec.sup.-1 150 150 150 150 150 Melt
viscosity ratio of the component A and the component -- 0.75 0.75
0.75 0.75 0.75 B (.eta.b/.eta.a) Sheath/core ratio (core
component/sheath component) -- 40/60 40/60 40/60 40/60 40/60
Content of the component A wt % 40 40 40 40 40 Linear discharge
velocity m/min 3.7 4.9 8.8 4.1 17.5 Spinning temperature .degree.
C. 245 245 245 245 245 Total stretching ratio -- 3.5 3.5 3.5 3.5
3.5 Second roll temperature .degree. C. 70 70 70 70 70 Third roll
temperature .degree. C. 135 135 135 135 135 Fourth roll temperature
.degree. C. 190 190 190 190 190 Crimp nozzle temperature .degree.
C. 230 230 230 230 230 Fourth roll speed m/min 3000 3000 3000 3000
3000 Winding speed m/min 2550 2550 2550 2550 2550 (1-winding
speed/fourth roll speed) .times. 100 % 15.0 15.0 15.0 15.0 15.0
Strength cN/dtex 2.4 2.1 2.5 2 2.5 Elongation % 45 45 45 45 45
Boiling water shrinkage % 3.1 1.8 4.2 1.6 4.5 Single fiber
thickness dtex 20 20 20 20 20 Non-circularity of single fiber --
1.4 3.8 1.2 4.2 1.0 Non-circularity of core component -- 1.4 3.8
1.2 4.2 1.0 U % (normal) -- 1 1.5 0.8 2.1 0.7 Crimp elongation
percentage after boiling water treatment % 25 25 25 25 25 Crimp
elongation percentage under load % 10 13 10 15 9 Minimum value of
thickness of sheath component .mu.m 6.4 2.4 7.5 0.8 8.2 CF value --
13 13 13 13 13 Total heat capacity of melting peak of fiber J/g 72
74 48 74 45 Spinnability .circleincircle. to X .circleincircle.
.largecircle. .largecircle. .largecircle. .circleincircle. Abrasion
loss ratio wt % 10 15 10 20 11 Peeling resistance .circleincircle.
to X .largecircle. .circleincircle. .largecircle. .largecircle.
.largecircle. 20 24 16 16 16 Bulkiness .circleincircle. to X
.largecircle. .circleincircle. .largecircle. .circleincircle.
.largecircle. Softness .circleincircle. to X .largecircle.
.circleincircle. .largecircle. .circleincircle. .largecircle.
Examples 42 to 44
[0524] BCF yarns of Examples 42 to 44 were obtained in the same way
as Example 36 except changing the chip fed to the core component
hopper in Example 36. Results of Examples 42 to 44 are shown in
Table 11, and the respective chips fed to the core component hopper
are shown in the following: [0525] Core component chip of Example
42: chip blend of P4/P8=90/10 (weight ratio) [0526] Core component
of Example 43: chip blend of P4/P9=90/10 (weight ratio) [0527] Core
component of Example 44: chip blend of P4/P10=90/10 (weight
ratio).
[0528] As can be understood from Examples 36 and 42 to 44, it was
found that, by containing the component C (compatibilizer) in the
crimped yarn, adhesion force of sheath/core interface was improved,
and a crimped yarn excellent in peeling resistance and abrasion
resistance could be obtained.
Example 45
[0529] A BCF yarn of Example 45 was obtained in the same way as
Example 36 except changing the chip fed to the sheath component
hopper in Example 36. The result of Example 45 was shown in Table
11, the chip fed to the sheath component hopper is shown in the
following: [0530] Sheath component chip of Example 45: chip blend
of N6-1/N6-4=80/20 (weight ratio) [0531] N6-4: nylon 6 containing
10 wt % EBA obtained by feeding dried N6-1 and a lubricant
(tradename, Alflow H-50L produced by NOF Corp.) (ethylene
bisstearic acid amide, hereafter, referred to as EBA) to a twin
screw kneading extruding machine such that N6-1:EBA=90:10 (weight
ratio), and kneading at cylinder temperature 220.degree. C.
Regarding the polymer, the melting point was 225.degree. C., the
heat capacity of melting peak was 81 J/g, the relative viscosity
was 2.59, and the melt viscosity was 150 Pasec.sup.-1.
[0532] As can be understood from Examples 36 and 45, it was found
that, by containing EBA (lubricant) in the crimped yarn to thereby
increase smoothness of fiber surface, external force became
difficult to be transmitted to the fiber, and a crimped yarn
excellent in peeling resistance and abrasion resistance can be
obtained.
TABLE-US-00012 TABLE 11 Item Example 42 Example 43 Example 44
Example 45 Component A -- P4/P8 blend P4/P9 blend P4/P10 blend P4
Melting point of the component A (Tma) .degree. C. 170 170 170 170
Melt viscosity of the component A (.eta.a) Pa sec.sup.-1 200 200
200 200 Component B -- N6-1 N6-1 N6-1 N6-1/N6-4 blend Melting point
of the component B (Tmb) .degree. C. 225 225 225 225 Melt viscosity
of the component B (.eta.b) Pa sec.sup.-1 150 150 150 150 Component
C -- LA-1 MADGIC Modiper -- Content of Component C wt % 0.8 0.8 1.6
-- Lubricant -- -- -- -- EBA Content of lubricant wt % -- -- -- 0.2
Melt viscosity ratio of the component A and the component -- 0.75
0.75 0.75 0.75 B (.eta.b/.eta.a) Sheath/core ratio (core
component/sheath component) -- 80/20 80/20 80/20 80/20 Content of
the component A wt % 79.2 79.2 78.4 79.2 Linear discharge velocity
m/min 7.1 7.1 7.1 7.1 Spinning temperature .degree. C. 245 245 245
245 Total stretching ratio -- 3.5 3.5 3.5 3.5 Second roll
temperature .degree. C. 70 70 70 70 Third roll temperature .degree.
C. 135 135 135 135 Fourth roll temperature .degree. C. 190 190 190
190 Crimp nozzle temperature .degree. C. 230 230 230 230 Fourth
roll speed m/min 3000 3000 3000 3000 Winding speed m/min 2550 2550
2550 2550 (1-winding speed/fourth roll speed) .times. 100 % 15 15
15 15 Strength cN/dtex 1.7 1.7 1.6 1.6 Elongation % 45 45 45 45
Boiling water shrinkage % 2.1 2.1 2 2 single fiber thickness dtex
20 20 20 20 Non-circularity of single fiber -- 3.0 3.0 3.0 3.0
Non-circularity of core component -- 3.0 3.0 3.0 3.0 U % (normal)
-- 1.3 1.3 1.3 1.3 crimp elongation percentage after boiling water
treatment % 25 25 25 25 Crimp elongation percentage under load % 4
4 4 6 Minimum value of thickness of sheath component .mu.m 0.9 0.9
0.9 0.9 CF value -- 13 13 13 13 Total heat capacity of melting peak
of fiber J/g 51 51 51 54 Spinnability .circleincircle. to X
.circleincircle. .circleincircle. .circleincircle. .circleincircle.
abrasion loss ratio wt % 16 16 15 15 Peeling resistance
.circleincircle. to X .largecircle. .largecircle. .largecircle.
.largecircle. 20 19 20 19 Bulkiness .circleincircle. to X .DELTA.
.DELTA. .DELTA. .largecircle. Softness .circleincircle. to X
.DELTA. .DELTA. .DELTA. .largecircle.
Examples 46 to 50
[0533] BCF yarns of Examples 46 to 50 were obtained in the same way
as Example 20 except changing the chips used as the component A and
the component B in Example 20. In Example 49, since it was
impossible to spin at the same spinning temperature as Example 20,
the spinning was carried out at spinning temperature 270.degree. C.
Results of Examples 46 to 50 are shown in Table 12, and the
respective component A and component B are shown in the following:
[0534] Example 46: component A/component B=P4/N11 [0535] Example
47: component A/component B=P4/(N6/N66) [0536] Example 48:
component A/component B=P4/N610 [0537] Example 49: component
A/component B=P4/N66 [0538] Example 50: component A/component
B=P7/N6-1 [0539] N11: nylon 11, melt viscosity 150 Pasec.sup.-1,
melting point 185.degree. C. and heat capacity of melting peak 42
J/g [0540] N6/N66: nylon in which monomers of nylon 6 and nylon 66
were copolymerized at a mol ratio 80/20, relative viscosity 2.59,
melting point 200.degree. C., heat capacity of melting peak 50 J/g
and melt viscosity 150 Pasec.sup.-1 [0541] N610: nylon 610,
relative viscosity 2.59, melting point 225.degree. C., heat
capacity of melting peak 68 J/g and melt viscosity 150 Pasec.sup.-1
[0542] N66: nylon 66, relative viscosity 2.59, melting point
260.degree. C., heat capacity of melting peak 73 J/g and melt
viscosity 150 Pasec.sup.-1.
[0543] As can be understood from Example 20 and Examples 46 to 48,
it was found that, by using the component B of which crystallinity
is high as the sheath component, crystallization of the sheath
component was further accelerated at the time of crimp processing,
and a crimped yarn excellent in peeling resistance could be
obtained. As the crystallinity of crimped yarn becomes high, the
crimp fastness becomes high, and it was a crimped yarn excellent on
texture of which bulkiness or softness of a circular knit fabric or
a carpet could be maintained for a long time.
[0544] As can be understood from Example 20 and Examples 49 to 50,
it is found that, by using the component A and the component B
having melting points in preferable range, it is possible to
prevent generating a viscosity unevenness inside the component A
due to heat degradation of the component A, a crimped yarn
excellent in peeling resistance can be obtained. Since there is no
viscosity unevenness inside the component A, it is easy that the
core component and the sheath component were uniformly oriented in
the spinning stretching step, and in the crimp processing,
difference of heat shrinking characteristics between the core
component and the sheath component is hardly generated. As a
result, since it becomes a crimped yarn of which boiling water
shrinkage is low, a crimped yarn excellent in peeling resistance
can be obtained.
[0545] In Example 20, compared to Examples 49 to 50, the core
component is disposed in the center portion of fiber cross-section,
and by constituting the core component and the sheath component
with polymers considered to be preferable, since fiber surface is
uniformly covered with the sheath component (i.e., minimum value of
thickness of sheath component is large), a crimped yarn excellent
in abrasion resistance can be obtained.
[0546] Furthermore, in Example 20, compared to Examples 49 to 50,
since crystallinity of crimped yarn is high, it was a crimped yarn
of which crimp fastness was high, and bulkiness or softness of a
circular knit fabric or a carpet could be maintained for a long
time, and its texture was excellent.
Example 51
[0547] A BCF yarn of Example 51 was obtained in the same way as
Example 20 except changing the spinning temperature in Example 20
to 270.degree. C. It cannot be said that spinnability was good, and
10 times yarn break occurred in 100 kg spinning.
[0548] As can be understood by comparing Example 20 and Example 51,
it is found that, by employing spinning temperature considered to
be preferable, heat degradation of the component A can be prevented
and spinnability can be improved.
[0549] Furthermore, as the viscosity unevenness by heat degradation
of the component A is suppressed more, a uniform orientation of the
core component and the sheath component becomes more easy in
spinning stretching step, and a difference of heat shrinking
characteristics between the core component and the sheath component
in the crimp processing step is hardly generated. As a result,
since it becomes a crimped yarn of which boiling water shrinkage is
low, it becomes a crimped yarn excellent in peeling resistance.
[0550] Furthermore, by preventing thermal degradation of the
component A, it became possible to dispose the core component in
center portion of fiber cross-section to thereby cover fiber
surface uniformly with the sheath component (minimum value of
sheath component is large), a crimped yarn excellent in abrasion
resistance was obtained.
TABLE-US-00013 TABLE 12 Example Example Example Example Item 46 47
48 49 Example 50 Example 51 Component A -- P4 P4 P4 P4 P7 P4
Melting point of the component A (Tma) .degree. C. 170 170 170 170
130 170 Melt viscosity of the component A (.eta.a) Pa sec.sup.-1
200 200 200 200 200 200 Component B -- N11 N6/N66 N610 N66 N6-1
N6-1 Melting point of the component B (Tmb) .degree. C. 185 200 225
260 225 225 Melt viscosity of the component B (.eta.b) Pa
sec.sup.-1 150 150 150 150 150 150 Melt viscosity ratio of the
component A and the component B -- 0.75 0.75 0.75 0.75 0.75 0.75
(.eta.b/.eta.a) Sheath/core ratio (core component/sheath component)
-- 40/60 40/60 40/60 40/60 40/60 40/60 Content of the component A
wt % 40 40 40 40 40 40 Linear discharge velocity m/min 7.3 7.3 7.3
7.3 7.3 7.3 Spinning temperature .degree. C. 245 245 245 270 245
270 Total stretching ratio -- 3.5 3.5 3.5 3.5 3.5 3.5 Second roll
temperature .degree. C. 70 70 70 70 70 70 Third roll temperature
.degree. C. 135 135 135 135 135 135 Fourth roll temperature
.degree. C. 190 190 190 190 190 190 Crimp nozzle temperature
.degree. C. 230 230 230 230 230 230 Fourth roll speed m/min 3000
3000 3000 3000 3000 3000 Winding speed m/min 2550 2550 2550 2550
2550 2550 (1-winding speed/fourth roll speed) .times. 100 % 15.0
15.0 15.0 15.0 15.0 15.0 Strength cN/dtex 1.9 2 2.4 1.6 1.6 1.6
Elongation % 45 45 45 45 45 45 Boiling water shrinkage % 5.8 5.3
2.4 5.5 5.6 5.3 Single fiber thickness dtex 20 20 20 20 20 20
Non-circularity of single fiber -- 3.0 3.0 3.0 3.0 3.0 3.0
Non-circularity of core component -- 3.0 3.0 3.0 3.0 3.0 3.0 U %
(normal) -- 1.6 1.8 1.5 2.5 2.8 2.4 CF value -- 13 13 13 13 13 13
Crimp elongation percentage after boiling water treatment % 25 25
25 25 25 25 Crimp elongation percentage under load % 8 10 10 4 4 4
Minimum value of thickness of sheath component .mu.m 2.7 3.0 2.9
1.1 0.9 1.0 Total heat capacity of melting peak of fiber J/g 40 48
53 48 42 47 Spinnability .circleincircle. to X .largecircle.
.largecircle. .circleincircle. .DELTA. .DELTA. .DELTA. Abrasion
loss ratio wt % 13 15 12 27 26 26 Peeling resistance
.circleincircle. to X .circleincircle. .largecircle.
.circleincircle. .DELTA. .DELTA. .DELTA. 21 20 23 14 14 14
Bulkiness .circleincircle. to X .largecircle. .largecircle.
.circleincircle. .DELTA. .DELTA. .DELTA. Softness .circleincircle.
to X .largecircle. .largecircle. .circleincircle. .DELTA. .DELTA.
.DELTA.
Example 52
[0551] In Example 36, an uncrimped stretched yarn was obtained in
the same way as Example 36 except using a spinning stretching
continuous heat treatment machine, i.e., using a machine in which a
yarn is wound after heat treatment without being subjected to an
air stuffer crimp processing. The condition for preparing stretched
yarn is shown in the following:
[0552] Preparing Condition of Stretched Yarn [0553] Kneading
machine temperature: 230.degree. C. [0554] Spinning temperature:
245.degree. C. [0555] Filtering layer: filled with 30# morundum
sand [0556] Filter: 20 .mu.m nonwoven fabric filter [0557]
Spinneret 2 (spinneret just before polymer discharge): slit width
0.15 mm, slit length 1.5 mm and number of holes 96 [0558] Spinneret
1 (spinneret 45 of the schematic view of FIG. 12. Positioned just
before spinneret 2 and has separate flow channels for core
component and sheath component): [0559] Sheath component; hole
diameter 0.5 mm, spinning hole length 0.5 mm and number of holes
per one filament 3 [0560] Core component; slit width 0.12 mm, slit
length 1.2 mm and number of holes per one filament 1 [0561] Out
put: 498.6 g/min (1 pack 1 yarn, 96 filaments) [0562] Sheath/core
ratio: core component/sheath component=80/20 [0563] Cooling:
uniflow of cooling length 1 m was used. Cooling air temperature
20.degree. C., wind speed 0.5 m/sec, cooling starting position was
0.1 m beneath spinneret surface [0564] Oiling agent: 10%
concentration emulsion oiling agent of aliphatic acid ester was
deposited to by 10% per yarn [0565] First roll temperature:
25.degree. C. [0566] Second roll temperature: 70.degree. C. [0567]
Third roll temperature: 135.degree. C. [0568] Fourth roll
temperature: 190.degree. C. [0569] Seventh roll temperature:
25.degree. C. [0570] First roll speed: 840 m/min (=second roll
speed/1.02) [0571] Second roll speed: 857 m/min [0572] Third roll
speed: 2400 m/min [0573] Fourth roll speed: 3000 m/min [0574]
Seventh roll speed: 2900 m/min [0575] Winding speed: 2860 m/min
[0576] Total stretching ratio: 3.5 times (second to third roll: 2.8
times, third to fourth roll: 1.25 times) [0577] Compressed air of
interlacing nozzle: 0.2 MPa.
[0578] The obtained stretched yarn was subjected to a false twist
processing (Breria processing) by using a false twist processing
machine shown in FIG. 13. That is, stretched yarn 50 unwound from
the stretched yarn cheese 48 is taken up by the feed roll 53 via
the yarn guides 49, 51 and 52, and then heated to heat set a twist
by the first heater 54 and cooled by the cooling plate 56 via the
yarn guide 55. After that, it is untwisted by the three axis type
twister 57 and taken up by the stretch roll 58. Next, it is heated
by the second heater 59 and, via the delivery roll 60 and the yarn
guide 61, interlaced by the interlacing nozzle 62 and then, via the
yarn guide 63, wound as the false twisted yarn 64. At this time,
the stretching false twist processing was carried out by adjusting
the stretch ratio to 1.05 times (=speed of stretch roll 58/speed of
feed roll 53), the temperature of the first heater 54 to
180.degree. C., the temperature of the second heater 59 to
200.degree. C., the D/Y ratio of the three axis type twister 57
(urethane disk) (=peripheral speed of urethane disk/speed of
stretch roll 58) to 1.7, the overfeed ratio (({speed of stretch
roll 58-speed of delivery roll 60}/speed of stretch roll
58).times.100) to 15%, the speed of the delivery roll 60 to 600
m/min and the compressed air of the interlacing nozzle to 0.2 MPa.
At this time, although it was not a level which causes a trouble,
yarn breaks arose 3 times in obtaining 100 kg false twisted yarn.
In the obtained false twisted yarn, the crimp elongation percentage
after boiling water treatment was 20%, the strength was 2.4
cN/dtex, single fiber thickness was 20 dtex, the boiling water
shrinkage was 6%, elongation was 45%, the minimum vale of thickness
of the sheath component was 0.8 .mu.m and the CF value was 13. In
peeling resistance evaluation of the false twisted yarn of Example
52, color fading, whitening and pilling generation were observed,
but it can be used when limited to clothing applications or the
like to which external force added is small (overall evaluation of
peeling resistance was .DELTA. (fair), overall evaluation was 12
points). The false twisted yarn of Example 52 had a crimp
configuration with an orientation in single fiber loop and also
with a residual torque, but the BCF yarn of Example 36 was
constituted by single fibers of which loop orientation and
oscillation thereof were more irregular and it was a crimped yarn
with no residual torque. That is, by a BCF yarn having a crimp
configuration considered to be preferable, it became possible to
disperse external force added to the crimped yarn to thereby obtain
a crimped yarn excellent in peeling resistance.
Comparative Example 13
[0579] A false twisted yarn was obtained in the same way as Example
52 except using in Example 52, a false twist processing machine
shown in FIG. 13 to the obtained stretched yarn and subjecting to a
false twist processing (woolly processing) in the following
condition. That is, the stretched yarn 50 unwound from the
stretched yarn cheese 48 is taken up by the feed roll 53 via the
yarn guides 49, 51 and 52, and then heated to heat set a twist by
the first heater 54 and cooled by the cooling plate 56 via yarn
guide 55. After that, it is untwisted by the three axis type
twister 57 and taken up by the stretch roll 58. Next, it is passed
to the delivery roll 60 by taking off the second heater 59 (not
heated) and, via the yarn guide 61, interlaced by the interlacing
nozzle 62 and then, via the yarn guide 63, wound as the false
twisted yarn 64. At this time, the stretching false twist
processing was carried out by adjusting the stretch ratio to 1.05
times (=speed of stretch roll 58/speed of feed roll 53), the
temperature of the first heater 54 to 180.degree. C., the D/Y ratio
of the three axis type twister 57 (urethane disk) (=peripheral
speed of urethane disk/speed of stretch roll 58) to 1.7, the speed
of the stretch roll 58 and the delivery roll 60 to 600 m/min and
the compressed air of the interlacing nozzle to 0.2 MPa. At this
time, although it was not a level which causes a trouble, yarn
breaks arose 3 times in obtaining 100 kg false twisted yarn. The
obtained false twisted yarn was a crimped yarn which exhibited a
good bulkiness as the crimp elongation percentage after boiling
water treatment was 25%, and the strength was 3.7 cN/dtex,
elongation was 28% and the boiling water shrinkage was 13%. In
peeling resistance evaluation of the false twisted yarn of
Comparative example 13, it was a crimped yarn of which appearance
was easy to be changed such that a whitening and pilling was
serious and a hole was opened, and was a fiber poor in practical
use in view of peeling resistance (overall evaluation of peeling
resistance was x (poor), overall evaluation was 5 points). As can
be understood by comparing Example 52 and Comparative example 13,
it was found that, by subjecting a yarn to a processing of highly
relaxing treatment while being heated after unwinding (Breria
processing) to thereby decrease orientation of amorphous portion
and accelerate crystallization to render both of strength and
boiling water shrinkage low, the peeling resistance could be
improved.
Example 53
[0580] As the component A, the polylactic acid P4 (melting point
170.degree. C., melt viscosity 200 Pasec.sup.-1), and as the
component B to be blended in core component, nylon 6 of relative
viscosity in sulfuric acid 2.15 (N-6-5, melting point 225.degree.
C., melt viscosity 60 Pasec.sup.-1) and as the component B to be
used as sheath component, nylon 6 of relative viscosity in sulfuric
acid 2.60 (N-6-6, melting point 225.degree. C., melt viscosity 150
Pasec.sup.1), were respectively dried and adjusted to water
contents from 50 to 100 ppm.
[0581] As spinning machine, a continuous spinning and crimping
machine equipped with a twin screw kneading machine shown in FIG.
14 was used, and an air stuffer crimped yarn was obtained by
continuously subjecting to a melt spinning, stretching, heat
treatment and crimping.
[0582] Component A (P4)/component B (N-1) were separately metered
and chip blended such that the blend ratio=40/60 (weight ratio) and
fed to the core component hopper 65 shown in FIG. 14, and the
component B (N-2) was fed to the sheath component hopper 66, and
the blend polymer of the component A and the component B, and the
component B were separately molten and kneaded by twin screw
extruding/kneading machines 67 and 68, respectively, and introduced
to the spinning block 69, the respective polymers were metered and
discharged by gear pumps 70 and 71, introduced to spinning pack 72
assembled therein and spun from spinneret 73 having 120 holes of
fine trilobal cross-sectional hole. At this time, numbers of
rotations of the gear pumps of the core component and the sheath
component were selected such that the compositing ratio of core
component/sheath component=80/20 (weight ratio) (the sheath/core
type composite fiber contains the component A 32 wt % with respect
to total weight). The yarn 75 was cooled and solidified by the
uniflow cooling apparatus 74, and oiled by the oiling device 76.
Further, after taking up by the first roll 77, stretched by the
speed ratio of the second roll 78 and the third roll 79, heat
treated by the third roll 79, further stretched by the speed ratio
of the third roll 79 and the fourth roll 80, heat treated again by
the fourth roll 80, imparting an air stuffer crimp by the crimping
nozzle 81 in which heated fluid is used while the yarn was relaxed
between the fourth roll and the cooling roll, structure of the
crimped yarn was fixed by cooling to room temperature on surface of
the roll 82, stretched between the sixth roll 83 and the seventh
roll 84 by loading a tension to an extent which does not extend the
crimp (0.05 to 0.10 cN/dtex, fiber thickness of wound crimped yarn
was used as the fiber thickness here) and wound by the winder 86 to
obtain an air stuffer crimped yarn of 1800 dtex 120 filaments
(cheese package 85) in which spinning, stretching, heat treatment
and crimping were carried out in one step. Approximately 100 kg was
sampled but yarn break, single fiber break or the like did not
occur and the spinning was extremely stable. The result of Example
53 is shown in Table 13.
[0583] The melt spinning, stretching, heat treatment and crimping
conditions were as follows: [0584] Kneading machine temperature:
230.degree. C. [0585] Spinning temperature: 240.degree. C. [0586]
Filtering layer: filled with 30# morundum sand [0587] Filter: 20
.mu.m nonwoven fabric filter [0588] Spinneret: slit width 0.15 mm,
slit length 1.5 mm and number of holes 120 [0589] Spinneret 2
(spinneret just before polymer discharge): slit width 0.15 mm, slit
length 1.5 mm and number of holes 120 [0590] Spinneret 1 (spinneret
45 of schematic view of FIG. 12. Positioned just before spinneret 2
and has separate flow channels of core component and sheath
component): [0591] Sheath component; hole diameter 0.4 mm, spinning
hole length 0.5 mm and number of holes per one filament 4 [0592]
Core component; slit width 0.08 mm, slit length 1.2 mm and number
of holes per one filament 1 [0593] Out put: 360 g/min (1 pack 1
yarn, 120 filaments) [0594] Cooling: uniflow of cooling length 1 m
was used. Cooling air temperature 20.degree. C., wind speed 0.5
m/sec, cooling starting position was 0.1 m beneath spinneret
surface [0595] Oiling agent: 10% concentration emulsion oiling
agent of aliphatic acid ester was deposited to by 10% per yarn
[0596] First roll temperature: 25.degree. C. [0597] Second roll
temperature: 75.degree. C. [0598] Third roll temperature:
140.degree. C. [0599] Fourth roll temperature: 190.degree. C.
[0600] Cooling roll temperature: 25.degree. C. [0601] Sixth roll
temperature: 25.degree. C. [0602] Seventh roll temperature:
25.degree. C. [0603] Heated steam treatment temperature:
225.degree. C. [0604] First roll speed: 690 m/min [0605] Second
roll speed: 700 m/min [0606] Third roll speed: 1750 m/min [0607]
Fourth roll speed: 2800 m/min [0608] Cooling roll speed: 80 m/min
[0609] Sixth roll speed: 2000 m/min [0610] Seventh roll speed: 2040
m/min [0611] Winding speed: 2000 m/min.
[0612] When cross-section of the obtained air stuffer crimped yarn
was observed by TEM, it was found that a uniformly dispersed
sea/island structure was formed, and diameter of the island
component was 0.05 to 0.30 .mu.m. Furthermore, since undyed
component constitutes the island component, it was an sea/island
structure in which the component A was the island and the component
B was the sea (polymer alloy structure a). Furthermore, it showed
excellent crimp characteristics as crimp elongation percentage 25%
and elongation percentage under load 19%, and it was a crimped yarn
having a crimp of which crimp was hardly lost. A carpet was
prepared by using the crimped yarn and as a result of carrying out
an abrasion resistance test, it showed an excellent abrasion
resistance as an abrasion loss ratio 10%. Furthermore, a circular
knit of the crimped yarn was prepared and as a result of evaluation
of iron heat resistance, it showed an excellent heat resistance as
exhibiting no appearance change at all. Melting points of the
crimped yarn by DSC were around 170.degree. C. (peak based on the
component A) and around 225.degree. C. (peak based on the component
B), i.e., melting peaks based on respective components were
observed, and total heat capacity of melting peak based on the
respective components was 74 J/g which indicated a sufficient
crystallinity.
Examples 54 to 57
[0613] Air stuffer crimped yarns of Examples 54 to 57 were obtained
in the same way as Example 53 except changing, in Example 53, the
blend ratio of the component A and the component B to be fed to the
core component hopper. Results of Examples 54 to 57 are shown in
Table 13 and respective blend ratios (weight ratio) of the
component A and the component B are described below: [0614] Example
54: component A/component B=20/80 [0615] Example 55: component
A/component B=55/45 [0616] Example 56: component A/component
B=70/30 [0617] Example 57: component A/component B=90/10.
[0618] From Examples 54 to 57, in the crimped yarn of sheath/core
type composite fiber, by containing the component B as a core
component, adhesion force of the sheath/core interface increases by
an interaction between the component B of the core component and
the component B of the sheath component and exhibits an excellent
abrasion resistance. Furthermore, by making the blend ratio of the
component A and the component B of the core component into the
range considered to be preferable, the polymer alloy structure of
the core component and the diameter of the island component can be
made into preferable range, and an air stuffer crimped yarn
excellent in abrasion resistance can be obtained. Since it has a
crimp of which crimp is hardly lost, qualities when used as carpet
represented by bulkiness can be maintained for a long time and
furthermore, a carpet with no degradation of the abrasion
resistance can be obtained.
TABLE-US-00014 TABLE 13 Example Item 53 Example 54 Example 55
Example 56 Example 57 Component A -- P4 P4 P4 P4 P4 Melting point
of the component A (Tma) .degree. C. 170 170 170 170 170 Melt
viscosity of the component A (.eta.a) Pa sec.sup.-1 200 200 200 200
200 Component B to be blended in core component -- N6-5 N6-5 N6-5
N6-5 N6-5 Melting point of the component B (Tmb) blended in core
component .degree. C. 225 225 225 225 225 Melt viscosity of the
component B (.eta.b) blended in core component Pa sec.sup.-1 60 60
60 60 60 Component B to be used as sheath component -- N6-6 N6-6
N6-6 N6-6 N6-6 Melting point of the component B to be used in
sheath component .degree. C. 225 225 225 225 225 Melt viscosity of
the component B to be used as sheath component Pa sec.sup.-1 150
150 150 150 150 Blend ratio of the component A and the component B
to be blended -- 40/60 20/80 55/45 70/30 90/10 in core component
(component A/component B) Melt viscosity ratio (.eta.b/.eta.a) of
Component A and the component B -- 0.30 0.30 0.30 0.30 0.30 to be
blended in core component Sheath/core weight ratio (core
component/sheath component) -- 80/20 80/20 80/20 80/20 80/20
Content of the component A wt % 32 16 44 56 72 Linear discharge
velocity m/min 4.3 4.4 4.3 4.3 4.2 Thickness of sheath component
.mu.m 2.2 2.2 2.2 2.2 2.2 Minimum value of thickness of sheath
component .mu.m 2.0 2.0 2.0 2.0 2.0 Polymer alloy structure* -- a a
a b b Diameter of island component .mu.m 0.05-0.30 0.05-0.70
0.05-1.1 0.05-0.5 0.05-0.20 Crimp elongation percentage after
boiling water treatment % 25 25 25 25 25 Crimp elongation
percentage under load % 19 20 18 14 12 Abrasion loss ratio wt % 10
9 13 15 18 Non-circularity -- 3.0 3.0 3.0 3.0 3.0 Strength of
Crimped yarn cN/dtex 2.5 2.6 2.5 2.2 2.2 Elongation of crimped yarn
% 45 45 45 45 45 Total heat capacity of melting peaks of Fiber J/g
74 79 63 59 52 Iron heat resistance .circleincircle. to XX
.circleincircle. .circleincircle. .circleincircle. .largecircle.
.largecircle. Spinnability .circleincircle. to .DELTA.
.circleincircle. .circleincircle. .circleincircle. .largecircle.
.largecircle. *Polymer alloy structure was evaluated as the
following a to c. a: Island component is the component A and sea
component is the component B b: Island component is the component B
and sea component is the component A c: Both of the component A and
the component B are sea component (sea/sea structure)
Examples 58 to 60
[0619] Air stuffer crimped yarns of Examples 58 to 60 were obtained
in the same way as Example 53 except, in Example 53, by changing
the composite ratio of the core component and the sheath component
and changing the thickness of sheath component of the stretched
yarn.
[0620] Regarding Examples 58 to 59, spinnability was excellent as
there was no yarn break and, on the other hand, in Example 60, yarn
break occurred 2 times in 100 kg spinning. Results of Examples 58
to 60 are shown in Table 14, and the respective compositing ratio
of the core component and the sheath component (weight ratio) are
shown below: [0621] Example 58: core component/sheath
component=85/15 [0622] Example 59: core component/sheath
component=90/10 [0623] Example 60: core component/sheath
component=95/5.
[0624] As can be understood by comparing Example 53 (Table 13) and
Examples 58 to 60 (Table 14), as the thickness of sheath component
becomes large, a crimped yarn of which crimp elongation percentage
is high, elongation percentage under load is high and excellent in
abrasion resistance can be obtained. As the sheath component
becomes thick, a high quality crimped yarn not only excellent in
abrasion resistance, but also of which elongation percentage under
load is high, that is, crimp is hardly lost, can be obtained.
TABLE-US-00015 TABLE 14 Example Example Example Item 58 59 60
Component A -- P4 P4 P4 Melting point of the component A (Tma)
.degree. C. 170 170 170 Melt viscosity of the component A (.eta.a)
Pa sec.sup.-1 200 200 200 Component B to be blended in core
component -- N6-5 N6-5 N6-5 Melting point of the component B to be
blended .degree. C. 225 225 225 in core component (Tmb) Melt
viscosity of the component B (.eta.b) to be blended Pa sec.sup.-1
60 60 60 in core component Component B to be used as sheath
component -- N6-6 N6-6 N6-6 Melting point of the component B to be
used as .degree. C. 225 225 225 sheath component Melt viscosity of
the component B to be used as Pa sec.sup.-1 150 150 150 sheath
component Blend ratio of the component A and the component B --
40/60 40/60 40/60 to be blended in core component (component
A/component B) Melt viscosity ratio of the component A and the --
0.30 0.30 0.30 component B to be blended in core component
(.eta.b/.eta.a) Sheath/core weight ratio (core component/sheath
component) -- 85/15 90/10 95/5 Content of the component A wt % 34
36 38 Linear discharge velocity m/min 4.3 4.3 4.3 Thickness of
sheath component .mu.m 1.6 1.1 0.5 Minimum value of thickness of
sheath component .mu.m 1.4 1.0 0.4 Polymer alloy structure* -- A A
A Diameter of island component .mu.m 0.05-0.30 0.05-0.30 0.05-0.30
Crimp elongation percentage after boiling water % 25 25 25
treatment Crimp elongation percentage under load % 16 14 12
Abrasion loss ratio wt % 11 14 17 Non-circularity -- 3.0 3.0 3.0
Strength of crimped yarn cN/dtex 2.5 2.4 2.3 Elongation of crimped
yarn % 45 45 45 Total heat capacity of melting peaks of fiber J/g
74 72 70 Iron heat resistance .circleincircle. to XX
.circleincircle. .circleincircle. .circleincircle. Spinnability
.circleincircle. to .DELTA. .circleincircle. .circleincircle.
.smallcircle. *Polymer alloy structure was evaluated as the
following a to c. a: Island component is the component A and sea
component is the component B. b: Island component is the component
B, sea component is the component A. c: Both of the component A and
the component B are sea component (sea/sea structure)
Examples 61 to 65
[0625] Air stuffer crimped yarns were obtained by subjecting to the
spinning, stretching, heat treatment and crimping in the same way
as Example 53 except changing, in Example 53, the fourth roll
temperature. Regarding Examples 53 and 61 to 64, spinnings were
extremely stable as Barus effects of the spun yarn were small and
there was no yarn break, but regarding Example 65, a slight
oscillation of yarn on the fourth roll occurred and yarn break
arose 1 time. Results of Examples 61 to 65 are shown in Table 15.
The fourth roll temperatures of Examples 61 to 65 are shown below:
[0626] Example 61: temperature of fourth roll=140.degree. C. [0627]
Example 62: temperature of fourth roll=150.degree. C. [0628]
Example 63: temperature of fourth roll=175.degree. C. [0629]
Example 64: temperature of fourth roll=200.degree. C. [0630]
Example 65: temperature of fourth roll=210.degree. C.
[0631] When Example 53 (Table 13), Examples 62 to 63 (Table 15) and
Examples 61 and 65 (Table 15) were compared, it is found that, by
making the crimp elongation percentage into the range considered to
be preferable, abrasion resistance is greatly improved. Since the
crimped yarns of Examples 53 and 62 to 63 are crimped yarns having
moderate crimp elongation percentages, the crimped yarns are hardly
fall down when abraded by an external force, and since they have
moderate flections or entanglements, external force was dispersed
to respective single fibers and the crimped yarns exhibited
excellent abrasion resistances.
TABLE-US-00016 TABLE 15 Example Example Example Item 61 62 Example
63 Example 64 65 Component A -- PLA-1 PLA-1 PLA-1 PLA-1 PLA-1
Melting point of the component A (Tma) .degree. C. 170 170 170 170
170 Melt viscosity of the component A (.eta.a) Pa sec.sup.-1 200
200 200 200 200 Component B to be blended in core component -- N6-5
N6-5 N6-5 N6-5 N6-5 Melting point of the component B (Tmb) to be
blended in .degree. C. 225 225 225 225 225 core component Melt
viscosity of the component B (.eta.b) to be blended in Pa
sec.sup.-1 60 60 60 60 60 Core component Component B to be used as
sheath component -- N6-6 N6-6 N6-6 N6-6 N6-6 Melting point of the
component B to be used as sheath .degree. C. 225 225 225 225 225
component Melt viscosity of the component B to be used as sheath Pa
sec.sup.-1 150 150 150 150 150 component Blend ratio (component
A/component B) of Component A -- 40/60 40/60 40/60 40/60 40/60 and
the component B to be blended in core component Melt viscosity
ratio (.eta.b/.eta.a) of Component A and -- 0.30 0.30 0.30 0.30
0.30 component B to be blended in core component Sheath/core weight
ratio (core component/sheath -- 80/20 80/20 80/20 80/20 80/20
component) Content of the component A wt % 32 32 32 32 32 Linear
discharge velocity m/min 4.3 4.3 4.3 4.3 4.3 Thickness of sheath
component .mu.m 2.2 2.2 2.2 2.2 2.2 Minimum value of thickness of
sheath component .mu.m 2.0 2.0 2.0 2.0 2.0 Polymer alloy structure*
-- a a a a a Diameter of island component .mu.m 0.05-0.20 0.05-0.20
0.05-0.20 0.05-0.20 0.05-0.20 Crimp elongation percentage after
boiling water treatment % 4 6 15 33 36 Crimp elongation percentage
under load % 2 4 11 25 28 Abrasion loss ratio wt % 25 18 13 8 18
Non-circularity -- 3.0 3.0 3.0 3.0 3.0 Strength of crimped yarn
cN/dtex 3.5 3 2.7 2.2 1.1 Elongation of crimped yarn % 45 45 45 45
45 Total heat capacity of melting peak of fiber J/g 72 73 74 74 75
Iron heat resistance .circleincircle. to XX .circleincircle.
.circleincircle. .circleincircle. .circleincircle. .circleincircle.
Spinnability .circleincircle. to .DELTA. .circleincircle.
.circleincircle. .circleincircle. .circleincircle. .largecircle.
*Polymer alloy structure was evaluated as the following a to c. a:
Island component is the component A and sea component is the
component B. b: Island component is the component B and sea
component is the component A. c: Both of the component A and the
component B are sea component (sea/sea structure)
Examples 66 to 68
[0632] Air stuffer crimped yarns of Examples 66 to 68 were obtained
by subjecting to spinning, stretching, heat treatment and crimping
in the same way as Example 53 except changing, in Example 53, the
specification of spinneret hole used and the non-circularity of air
stuffer crimped yarn to be obtained. Results of Examples 66 to 68
are shown in Table 16. The specifications of spinneret used in
Examples 66 to 68 are shown below: [0633] Example 66 [0634]
Spinneret 2 (spinneret just before polymer discharge): slit width
0.20 mm, slit width 0.8 mm and number of holes 120 [0635] Example
67 [0636] Spinneret 2 (spinneret just before polymer discharge):
slit length 0.18 mm, slit width 1.0 mm and number of holes 120
[0637] Example 68 [0638] Spinneret 2 (spinneret just before polymer
discharge): slit length 0.12 mm, slit width 1.8 mm and number of
holes 120.
[0639] As can be understood by comparing Example 53 (Table 13) and
Examples 66 to 68, by making an air stuffer crimped yarn of which
non-circularity is high, abrasion resistance becomes excellent.
That is, as the non-circularity of crimped yarn becomes high,
diameter of island component becomes easy to be fine in spinning
step and since it has a polymer alloy structure of which islands
are uniformly dispersed, adhesion force in the interface of
component A/component B of the core component and the component B
of the of the sheath component increases, and an excellent crimped
yarn excellent in abrasion resistance with no fibrillation is
obtained. Furthermore, by changing to a crimped yarn of which
non-circularity is high, it becomes a crimped yarn of which crimp
is hardly lost, i.e., it becomes a crimped yarn of which abrasion
resistance does not decrease even when used for a long time.
TABLE-US-00017 TABLE 16 Example Example Example Item 66 67 68 the
component A -- P4 P4 P4 Melting point of the component A (Tma)
.degree. C. 170 170 170 Melt viscosity of the component A (.eta.a)
Pa sec.sup.-1 200 200 200 the component B to be blended in core
component -- N6-5 N6-5 N6-5 Melting point of the component B (Tmb)
to be blended in .degree. C. 225 225 225 core component Melt
viscosity of the component B (.eta.b) blended in core Pa sec.sup.-1
60 60 60 component Component B to be used as sheath component --
N6-6 N6-6 N6-6 Melting point of the component B to be blended in
sheath .degree. C. 225 225 225 component Melt viscosity of the
component B to be blended in sheath Pa sec.sup.-1 150 150 150
component blend ratio of the component A and the component B to be
-- 40/60 40/60 40/60 blended in core component (component
A/component B) melt viscosity ratio of the component A and the
component B -- 0.30 0.30 0.30 to be blended in core component
(.eta.b/.eta.a) sheath/core weight ratio (core component /sheath --
80/20 80/20 80/20 component) Content of the component A wt % 32 32
32 linear discharge velocity m/min 6.1 5.4 4.5 Thickness of sheath
component .mu.m 2.2 2.2 2.2 Minimum value of thickness of sheath
component .mu.m 2.1 2.1 1.9 polymer alloy structure* -- a a a
Diameter of island component .mu.m 0.05-0.45 0.05-0.35 0.05-0.20
crimp elongation percentage after boiling water treatment % 25 25
25 Crimp elongation percentage under load % 10 14 20 abrasion loss
ratio wt % 19 15 8 non-circularity -- 1.2 1.3 4.0 strength of
crimped yarn cN/dtex 2.5 2.5 2.4 elongation of crimped yarn % 45 45
45 total heat capacity of melting peaks of fiber J/g 71 72 70 Iron
heat resistance .circleincircle. to xx .circleincircle.
.circleincircle. .circleincircle. Spinnability .circleincircle. to
.DELTA. .circleincircle. .circleincircle. .circleincircle. *Polymer
alloy structure was evaluated as the following a to c. a: Island
component is the component A and sea component is the component B.
b: Island component is the component B and sea component is the
component A. c: Both of the component A and the component B are sea
component (sea/sea structure)
Example 69
Spinning.cndot.Stretching.cndot.Crimp Processing
[0640] Polylactic acid P4 as the component A and nylon 6 (melt
viscosity 580 poise, melting point 225.degree. C.) as the component
B are kneaded in an extruding machine at kneading mass ratio
(polylactic acid:nylon) 30:70 at kneading temperature 230.degree.
C., and supplied to a spinning machine.
[0641] Spinning temperature in the spinning machine was adjusted to
230.degree. C., and after the molten polymer mixture was filtered
in a spinning pack by a metallic nonwoven fabric filter of mesh
size 20 .mu.m, it was discharged as a yarn from a spinneret having
Y type hole of number of holes 54.
[0642] The spun yarn discharged from the spinneret was, after
cooled and solidified by a chimney wind, imparted with an oiling
agent liquid of 25% by weight diluted with low viscosity mineral
oil and then contacted around a take-up roll (Nelson type roll,
rotation speed 700 m/min, roll temperature 65.degree. C.).
[0643] The yarn was not wound and successively subjected to first
stretching by contacting around first stretch roll (Nelson type
roll, rotation speed 600 m/min, roll temperature 110.degree. C.).
Furthermore, the yarn was, without winding, successively subjected
to second stretching by contacting around second stretch roll
(Nelson type roll, rotation speed 1800 m/min, roll temperature
150.degree. C.).
[0644] Without winding the yarn, the stretched yarn was
successively introduced to a crimp processing machine and subjected
to a crimp processing by hot compressed air of 170.degree. C. and
0.8 MPa, and ejected on a rotating conveyor and cooled. Next,
plug-like crimped yarn piece was stretched by a pair of separate
roll to unravel the piece. The crimped yarn was interlaced, wound
into a cheese to obtain a crimped yarn of 2000 dtex-94fil.
[0645] As to the obtained crimped yarn, island/sea relation of
polylactic acid resin and nylon 6 in the fiber was observed and, by
treating with aqueous solution of sodium hydroxyide, since the
island structure was dissolved and the sea structure remained, it
was confirmed that polylactic acid resin formed the island
structure and nylon 6 formed the sea structure.
[0646] The domain size of the island structure was 25 to 400 nm
(average 180 nm).
[0647] The non-circularity of the Y type fiber cross-section was
1.34.
(Yarn Twisting)
[0648] The above-mentioned crimped yarn was twisted at 160 t/m
S-twist as first twist, furthermore 2 yarns were paralleled and
twisted at 160 t/m Z-twist as second twist, and heat set at
105.degree. C.
(Dyeing)
[0649] Since nylon 6 forms the covering component, to dye nylon 6
with a metalcomplex dye, the dyeing treatment was carried out in
the following way.
[0650] A dyeing bath of bath ratio 1:15 was prepared in a dyeing
machine, IRGALAN (R) Black RBLN 2.0% owf as a metal-complex dye,
acetic acid 0.5 g/l and ammonium sulfate 0.5 .mu.l as a dyeing
auxiliary agent were added, and in the dyeing bath, the
above-mentioned twisted yarn was put and subjected to a dyeing
treatment at 90.degree. C. for 20 minutes.
(Base Cloth)
[0651] A spunbond nonwoven fabric of single fiber thickness 5.5
dtex and weight 100 g/m.sup.2 was obtained from the polylactic acid
P4 as the base cloth of carpet.
(Tufting)
[0652] The above-mentioned twisted yarn was tufted to the
above-mentioned base cloth at 1/8 gauge and 6.8 stitch/mm to
thereby obtain a loop carpet for car option mat of pile weight 700
g/m.sup.2.
[0653] Abrasion loss ratio of the obtained carpet was, at 300
rotation abrasion, 3.5%, at 5500 rotation abrasion, 33.3%, and an
abrasion loss ratio after wet heat degradation was 5.2%, i.e., it
exhibited an excellent abrasion resistance. The obtained carpet for
option mat exhibited a deep excellent color.
Example 70
Spinning.cndot.Stretching.cndot.Crimp Processing
[0654] A spinning stretching crimp processing were carried out in
the same way as Example 69.
(Yarn Twisting)
[0655] Yarn twisting was carried out in the same way as Example
69.
(Dyeing)
[0656] A dyeing was carried out in the same way as Example 69.
(Base Cloth)
[0657] The same one as Example 69 was used as the base cloth of
carpet.
(Tufting)
[0658] The above-mentioned twisted yarn was tufted to the
above-mentioned base cloth, at 1/8 gauge and 7.5 stitch/mm and the
pile ends were cut to obtain a saxony carpet for car option mat of
which pile length was 10 mm and pile weight was 1100 g/m.sup.2.
[0659] The abrasion loss ratio of the obtained carpet for option
mat was, at 300 rotation abrasion, 2.2%, at 5500 rotation abrasion,
20.8% and abrasion loss ratio after wet heat degradation was 3.1%,
i.e., it exhibited a good abrasion resistance. The obtained carpet
for option mat exhibited a deep and excellent color.
Example 71
Spinning.cndot.Stretching.cndot.Crimp Processing
[0660] Spinning.cndot.stretching.cndot.crimp processing was carried
out in the same way as Example 69 except changing the total output
of polymer and the number of holes of spinneret, and obtained a
crimped yarn of 1450 dtex-54fil.
[0661] As to the obtained crimped yarn, island/sea relation of
polylactic acid resin and nylon 6 in the fiber was observed and, by
treating with aqueous solution of sodium hydroxyide, since the
island structure was dissolved and the sea structure remained, it
was confirmed that polylactic acid resin formed the island
structure and nylon 6 formed the sea structure.
[0662] The domain size of the island structure was 25 to 400 nm
(average 200 nm).
[0663] The non-circularity the Y type fiber cross-section was
1.34.
(Yarn Twisting)
[0664] Yarn twisting was not carried out.
(Dyeing)
[0665] Since nylon 6 forms the covering component, to dye nylon 6,
dyeing was carried out in the same way as Example 69.
(Base Cloth)
[0666] The same one as that of Example 69 was used as a base cloth
of carpet.
(Tufting)
[0667] The above-mentioned crimped yarn was tufted to the
above-mentioned base cloth at 1/10 gauge and 12 stitch/mm, and the
pile ends were cut to obtain a velour carpet for car line mat of
which pile length was 6 mm and pile weight was 450 g/m.sup.2.
[0668] The abrasion loss ratio of the obtained carpet was, at 300
rotation abrasion, 2.6% and abrasion loss ratio after wet heat
degradation was 4.2%, i.e., it exhibited a good abrasion
resistance. The obtained carpet exhibited a deep excellent color.
The heat resistance of the obtained carpet was good as there was no
thermal bond.
Comparative Example 16
Spinning-Stretching-Crimping Processing
[0669] A crimped yarn was obtained in the same way as Example 69
except changing the kneading mass ratio of polylactic acid and
nylon to 100:0.
(Yarn Twisting)
[0670] Yarn twisting was carried out in the same way as Example
69.
(Dyeing)
[0671] Since it was 100% by weight polylactic acid resin, to dye
polylactic acid resin with a disperse dye, dyeing treatment was
carried out in the following way.
[0672] A dyeing bath of bath ratio 1:15 was prepared in a dyeing
machine and, as disperse dyes, Disperse Yellow KT-1, Disperse Red
KT-1, Disperse Blue KT-1 5% owf as total dye concentration, as
dyeing auxiliary agent, acetic acid 0.5 g/l and Nicca Sunsalt
RM-340 (produced by Nicca Chemical Co.) 0.5 g/l were added, and the
above-mentioned twisted yarn was put in the dyeing bath and
subjected to a dyeing treatment at 110.degree. C. for 30
minutes.
(Base Cloth)
[0673] The same one as that of Example 69 was used as a base cloth
for carpet.
(Tufting)
[0674] The crimped yarn was tufted in the same way as Example 69 to
thereby obtain a loop carpet of pile weight 700 g/m.sup.2.
[0675] The abrasion loss ratio of the obtained carpet was, at 300
rotation abrasion, 6.3%, at 5500 rotation abrasion, 95.2% and
abrasion loss ratio after wet heat degradation was 25.2%, i.e.,
every value was inferior to those of Example 69.
Comparative Example 17
Spinning.cndot.Stretching.cndot.Crimping Processing
[0676] A crimped yarn was obtained in the same way as Example 69
except changing the kneading mass ratio of polylactic acid and
nylon to 70:30.
[0677] As to the obtained crimped yarn, island/sea relation of
polylactic acid resin and nylon 6 in the fiber was observed and,
since sea structure was dissolved out and island structure remained
after being treated with aqueous solution of sodium hydroxide, it
was confirmed that polylactic acid resin formed the sea structure
and nylon 6 formed the island structure.
(Yarn Twisting)
[0678] Yarn twisting was carried out in the same way as Example
69.
(Dyeing)
[0679] Since polylactic acid resin formed covering component, to
dye polylactic acid resin with a disperse dye, dyeing was carried
out in the same way as Comparative example 16.
(Base Cloth)
[0680] The same one as that of Example 69 was used as a base cloth
for carpet.
(Tufting)
[0681] The above-mentioned twisted yarn was tufted to the
above-mentioned base cloth at 1/8 gauge and 7.5 stitch/mm and the
pile ends were cut to thereby obtain a saxony carpet of which pile
length was 10 mm and pile weight was 1100 g/m.sup.2.
[0682] The abrasion loss ratio of the obtained carpet was, at 300
rotation abrasion, 3.2%, at 5500 rotation abrasion, 75.1%, and
abrasion loss ratio after wet heat degradation was 18.8%, i.e., it
was inferior to that of Example 70.
Comparative Example 18
Spinning.cndot.Stretching.cndot.Crimping Processing
[0683] A crimped yarn was obtained in the same way as Example 69
except changing the kneading mass ratio of polylactic acid and
nylon to 100:0.
(Yarn Twisting)
[0684] Yarn twisting was carried out in the same way as Example
69.
(Dyeing)
[0685] Since it was 100% by weight polylactic acid resin, to dye
polylactic acid resin with a disperse dye, dyeing was carried out
in the same way as Comparative example 16.
(Base Cloth)
[0686] The same one as that of Example 69 was used as a base cloth
for carpet.
(Tufting)
[0687] The above-mentioned twisted yarn was tufted to the
above-mentioned base cloth at 1/8 gauge and 7.5 stitch/mm, and the
pile ends were cut to thereby obtain a saxony carpet of which pile
length was 10 mm and pile weight was 1100 g/m.sup.2.
[0688] The abrasion loss ratio of the obtained carpet was, at 300
rotation abrasion, 2.4%, at 5500 rotation abrasion, 85.6%, and
abrasion loss ratio after wet heat degradation was 19.9%, i.e., it
was inferior to that of Example 70.
Comparative Example 19
Spinning.cndot.Stretching.cndot.Crimping Processing
[0689] A spinning.cndot.stretching.cndot.crimping processing was
carried out in the same way as Example 69 except changing the total
output of polymer and the number of holes of spinneret and the
kneading mass ratio of polylactic acid and nylon to 70:30, and
obtained a crimped yarn of 1450 dtex-54fil.
[0690] As to the obtained crimped yarn, island/sea relation of
polylactic acid resin and nylon 6 in the fiber was observed and,
since sea structure was dissolved out and island structure remained
after being treated with aqueous solution of sodium hydroxide, it
was confirmed that polylactic acid resin formed the sea structure
and nylon 6 formed the island structure.
(Yarn Twisting)
[0691] Yarn twisting was not carried out.
(Dyeing)
[0692] Since polylactic acid resin formed covering component, to
dye polylactic acid resin with a disperse dye, dyeing was carried
out in the same way as Comparative example 16.
(Base Cloth)
[0693] The same one as that of Example 69 was used as a base cloth
for carpet.
(Tufting)
[0694] The above-mentioned crimped yarn was tufted to the
above-mentioned base cloth at 1/10 gauge and 12 stitch/mm, and the
pile ends were cut to thereby obtain a velour carpet of which pile
length was 6 mm and pile weight was 450 g/m.sup.2.
[0695] The abrasion loss ratio of the obtained carpet was, at 300
rotation abrasion, 40.2%, and abrasion loss ratio after wet heat
degradation was 50.3%, i.e., it was inferior to that of Example 71.
The heat resistance of the obtained carpet was inferior to that of
Example 71, as a fusion bond of the pile occurred in the test.
Comparative Example 20
Spinning.cndot.Stretching.cndot.Crimping Processing
[0696] A spinning.cndot.stretching.cndot.crimping processing was
carried out in the same way as Example 69 except changing the total
output of polymer, the spinneret and the kneading mass ratio of
polylactic acid and nylon to 100:0, and obtained a crimped yarn of
1450 dtex-54fil.
(Yarn Twisting)
[0697] Yarn twisting was not carried out.
(Dyeing)
[0698] Since it was 100 weight % polylactic acid resin, to dye
polylactic acid resin with a disperse dye, dyeing was carried out
in the same way as Comparative example 16.
(Base Cloth)
[0699] The same one as that of Example 69 was used as a base cloth
for carpet.
(Tufting)
[0700] The above-mentioned crimped yarn was tufted to the
above-mentioned base cloth at 1/10 gauge and 12 stitch/mm, and pile
ends were cut to obtain a velour carpet of which pile length was 6
mm and pile weight was 450 g/m.sup.2.
[0701] The abrasion loss ratio of the obtained carpet was, at 300
rotation abrasion, 43.4%, and abrasion loss ratio after wet heat
degradation was 70.2%, i.e., it was inferior to that of Example
71.
[0702] The heat resistance of the obtained carpet was inferior to
that of Example 71, as a fusion bond of the pile occurred in the
test.
Comparative Example 21
Spinning.cndot.Stretching.cndot.Crimping Processing
[0703] A spinning.cndot.stretching.cndot.crimping processing was
carried out in the same way as Example 69 except changing the total
output of polymer, the spinneret and the kneading mass ratio of
polylactic acid and nylon to 0:100 to thereby obtain a crimped yarn
of 1560 dtex-96fil.
(Yarn Twisting)
[0704] The above-mentioned crimped yarn was twisted at 140 t/m
S-twist as first twist and 2 yarns were paralleled and furthermore,
twisted at 140 t/m Z-twist as second twist, and heat set at
125.degree. C.
(Dyeing)
[0705] To dye nylon 6, dyeing was carried out in the same way as
Example 69.
(Base Cloth)
[0706] The same one as that of Example 69 was used as a base cloth
for carpet.
(Tufting)
[0707] The above-mentioned twisted yarn was tufted to the
above-mentioned base cloth at 1/10 gauge and 8.5 stitch/mm, and
pile ends were cut to thereby obtain a saxony carpet of which pile
length was 10 mm and pile weight was 1100 g/m.sup.2.
[0708] The abrasion loss ratio of the obtained carpet was, at 300
rotation abrasion, 1.0%, at 5500 rotation abrasion, 9.2%, and
abrasion loss ratio after wet heat degradation was 2.1%, i.e., it
exhibited a good abrasion resistance. The obtained carpet was
inferior in color brightness to those of Examples.
TABLE-US-00018 TABLE 17 Example Example Example Comparative
Comparative Item 69 70 71 example 16 example 17 Raw yarn Fiber
thickness dtex 2000 2000 1450 2000 2000 Pile component PLA/N6
PLA/N6 PLA/N6 PLA PLA/N6 Sea component N6 N6 N6 PLA PLA Weight
ratio PLA/N6 30/70 30/70 30/70 100/0 70/30 N6 melt viscosity poise
580 580 580 -- 580 PLA melt viscosity poise 1210 1210 1210 1210
1210 Tensile strength cN/dtex 3.04 3.04 3.04 1.78 2.12 Yarn
unevenness U % 1.55 1.55 1.55 1.34 3.12 Twisted yarn 2ply 2ply --
2ply 2ply 160S/160Z 160S/160Z 160S/160Z 160S/160Z Tuft Texture loop
saxony velour loop saxony Weight g/m2 700 1100 450 700 1100 Use --
option mat option mat line mat option mat option mat Abrasion loss
ratio 300 times % 3.5 2.2 2.6 6.3 3.2 Abrasion loss ratio 5500
times % 33.3 20.8 -- 95.2 75.1 Abrasion loss ratio after 300 times
% 5.2 3.1 4.2 25.2 18.8 Wet heat degradation Line mat heat
resistance grade -- -- .circleincircle. -- -- Color brightness
grade .circleincircle. .circleincircle. .circleincircle. .DELTA.
.largecircle. Comparative Comparative Comparative Comparative Item
example 18 example 19 example 20 example 21 Raw yarn Fiber
thickness dtex 2000 1450 1450 1560 Pile component PLA PLA/N6 PLA N6
Sea component PLA PLA PLA -- Weight ratio PLA/N6 100/0 70/30 100/0
0/100 N6 melt viscosity poise -- 580 -- 580 PLA melt viscosity
poise 1210 1210 1210 -- Tensile strength cN/dtex 1.78 2.12 1.78
3.52 Yarn unevenness U % 1.34 3.12 1.34 1.10 Twisted yarn 2ply --
-- 2ply 160S/160Z 140S/140Z Tuft Texture saxony velour velour
saxony Weight g/m2 1100 450 450 1100 Use -- option mat line mat
line mat option mat Abrasion loss ratio 300 times % 2.4 40.2 43.4
1.0 Abrasion loss ratio 5500 times % 85.6 -- -- 9.2 Abrasion loss
ratio after 300 times % 19.9 50.3 70.2 2.1 Wet heat degradation
Line mat heat resistance grade -- X X -- Color brightness grade
.DELTA. .largecircle. .DELTA. .DELTA. PLA: polylactic acid N6:
nylon 6
Example 72
Spinning.cndot.Stretching
[0709] Polylactic acid P4 as the component A and nylon 6 (melt
viscosity 580 poise, melting point 225.degree. C.) as the component
B were mixed and kneaded by an extruding machine at kneading mass
ratio (polylactic acid:nylon) 30:70 and kneading temperature
230.degree. C., and supplied to a spinning machine.
[0710] Spinning temperature in the spinning machine was adjusted to
230.degree. C., and after the polymer mixture was filtered in the
spinning pack by a metallic nonwoven fabric filter of mesh size 20
.mu.m, it was discharged as a yarn from a spinneret having circular
holes of which number of holes was 26.
[0711] At spinning speed 2000 m/min, an unstretched yarn of 252
dtex-26fil was wound and, after that, subjected to a one stage
stretching by a vertical type stretching machine in a condition of
stretch ratio 3.0 times, stretching temperature 90.degree. C. and
set temperature 130.degree. C. to thereby obtain a stretched yarn
of 84 dtex-26fil.
[0712] As to the obtained stretched yarn, island/sea relation of
polylactic acid resin and nylon 6 in the fiber was observed and,
since the island structure was dissolved and the sea structure
remained after treating with aqueous solution of sodium hydroxide,
it was confirmed that polylactic acid resin formed the island
structure and nylon 6 formed the sea structure.
[0713] The domain size of the island structure was 15 to 200 nm
(average 100 nm).
(Yarn Assembling-Knitting)
[0714] 4 of the obtained stretched yarn were assembled and a double
jersey for car sheets were prepared.
(Dyeing)
[0715] Since nylon 6 formed covering component, to dye nylon 6 with
metal-complex dye, dyeing treatment was carried out in the
following way.
[0716] A dyeing bath of bath ratio 1:15 was prepared in a dyeing
machine, by adding IRGALAN (R) Black RBLN 2.0% owf as metal-complex
dyes, acetic acid 0.5 g/l and ammonium sulfate 0.5 g/l as dyeing
auxiliary agent, and the above-mentioned twisted yarn was put into
the dyeing bath, and a dyeing treatment was carried out at
90.degree. C. for 20 minutes.
[0717] The obtained car sheet had a strength having no problem in
practical use, and strength retention at 90.degree. C. atmosphere
was also of no problem in practical use as 67.9%, and abrasion
resistance was also good.
Example 73
Spinning.cndot.Stretching
[0718] A stretched yarn of 84 dtex-26fil was obtained in the same
way as Example 72 except changing the kneading mass ratio of
polylactic acid and nylon (polylactic acid:nylon) to 20:80.
[0719] As to the obtained stretched yarn, island/sea relation of
polylactic acid resin and nylon 6 in the fiber was observed and, by
treating with aqueous solution of sodium hydroxide, since the
island structure was dissolved and the sea structure remained, it
was confirmed that polylactic acid resin formed the island
structure and nylon 6 formed the sea structure.
(Yarn Assembling-Knitting)
[0720] 4 of the obtained stretched yarn were assembled and a double
jersey for car sheets was prepared.
(Dyeing)
[0721] Since nylon 6 formed the covering component, to dye nylon 6
with a metal-complex dye, dyeing was carried out in the same way as
Example 72.
[0722] The obtained fabric had strength of no problem in practical
use, and, strength retention in 90.degree. C. atmosphere was also
of no problem in practical use as 75.8%, and abrasion resistance
was also good.
Comparative Example 22
Spinning.cndot.Stretching
[0723] A stretched yarn of 84 dtex-26fil was obtained in the same
way as Example 72 except changing the kneading mass ratio of
polylactic acid and nylon (polylactic acid:nylon) to 70:30.
[0724] As to the obtained stretched yarn, island/sea relation of
polylactic acid resin and nylon 6 in the fiber was observed and,
since sea structure was dissolved out and sea structure remained
after treatment of an aqueous solution of sodium hydroxide, it was
confirmed that polylactic acid resin formed the sea structure and
nylon 6 formed the island structure.
(Yarn Assembling.cndot.Knitting)
[0725] 4 of the obtained stretched yarn were assembled and prepared
a double jersey for car sheets.
(Dyeing)
[0726] Since polylactic acid resin formed covering component, to
dye polylactic acid resin with a disperse dye, dyeing was carried
out in the same way as Comparative example 16.
[0727] The obtained fabric was low in strength retention at
90.degree. C. atmosphere as 29.3%, and abrasion resistance was also
inferior to that of Example 72, and its practical use was difficult
as a result.
Comparative Example 23
Spinning.cndot.Stretching
[0728] A stretched yarn was obtained in the same way as Example 72
except changing the kneading mass ratio of polylactic acid and
nylon to 100:0.
(Yarn Assembling.cndot.Knitting)
[0729] 4 of the obtained stretched yarn were assembled, and a
double jersey was prepared in the same way as Example 72.
(Dyeing)
[0730] Since it was 100% by weight polylactic acid resin, to dye
polylactic acid resin with a disperse dye, dyeing was carried out
in the same way as Comparative example 16.
[0731] The obtained fabric was low in strength retention in
90.degree. C. atmosphere as 25.6%, and abrasion resistance was also
inferior to that of Example 72, and its practical use was difficult
as a result.
TABLE-US-00019 TABLE 18 Example Example Comparative Comparative
Item 72 73 example 22 example 23 Raw Fiber thickness dtex 84 84 84
84 yarn Yarn component PLA/N6 PLA/N6 PLA/N6 PLA Sea component N6 N6
PLA PLA Weight ratio PLA/N6 30/70 20/80 70/30 100/0 N6 melt
viscosity poise 580 580 580 -- PLA melt viscosity poise 1210 1210
1210 1210 Tensile strength cN/dtex 4.3 4.5 3.2 4.3 Yarn unevenness
U % 1.1 0.9 1.6 0.8 Fabric Knit structure double jersey double
jersey double jersey double jersey mocro cloth mocro cloth mocro
cloth mocro cloth Wale W/inch 29 29 30 29 Course C/inch 48 42 40 42
Weight g/m.sup.2 618 498 512 498 Dyeing condition .degree. C.
.times. min 90 .times. 30 90 .times. 30 105 .times. 30 110 .times.
30 Tensile strength N 1286 1336 638 899 Strength retention at %
67.9 75.8 29.3 25.6 90.degree. C. atmosphere Abrasion loss of g
0.15 0.11 0.50 0.47 Fabric
INDUSTRIAL APPLICABILITY
[0732] It is possible to provide a crimped yarn and a fiber
structure constituted by a synthetic fiber comprising an aliphatic
polyester resin and a thermoplastic polyamide resin excellent in
abrasion resistance as well as aesthetic appearance after dyeing,
and it is possible to provide a synthetic fiber and a fiber
structure most suitable for general apparel applications or
industrial material applications.
* * * * *