U.S. patent application number 16/761968 was filed with the patent office on 2020-10-08 for high-strength fine-denier polyester multifilament.
The applicant listed for this patent is Toray Industries, Inc.. Invention is credited to Minoru Fujimori, Yusuke Ono, Ryota Suzuki.
Application Number | 20200318260 16/761968 |
Document ID | / |
Family ID | 1000004968143 |
Filed Date | 2020-10-08 |
United States Patent
Application |
20200318260 |
Kind Code |
A1 |
Ono; Yusuke ; et
al. |
October 8, 2020 |
HIGH-STRENGTH FINE-DENIER POLYESTER MULTIFILAMENT
Abstract
In a polyester multifilament, a core-component high-viscosity
polyester and sheath-component low-viscosity polyester have been
composited into a core-in-sheath, wherein the difference in
intrinsic viscosity between the core component and the sheath
component is 0.20 to 1.00, the total fineness is 4 to 30 dtex, the
single-yarn fineness is 1.0 to 5.0 dtex; the breaking strength is
5.0 to 9.0 cN/dtex, the fracture elongation is 12 to 45%, the
degree of interlacement is 2.0 to 15.0/m, and the number of
filaments thereof is 3 to 15.
Inventors: |
Ono; Yusuke; (Mishima-shi,
JP) ; Suzuki; Ryota; (Mishima-shi, JP) ;
Fujimori; Minoru; (Nomi-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Toray Industries, Inc. |
Tokyo |
|
JP |
|
|
Family ID: |
1000004968143 |
Appl. No.: |
16/761968 |
Filed: |
November 9, 2018 |
PCT Filed: |
November 9, 2018 |
PCT NO: |
PCT/JP2018/041591 |
371 Date: |
May 6, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
D01F 8/14 20130101 |
International
Class: |
D01F 8/14 20060101
D01F008/14 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 28, 2017 |
JP |
2017-227923 |
Claims
1. A polyester multifilament comprising: a high-viscosity polyester
as a core component; and a low-viscosity polyester as a sheath
component, the core component and the sheath component forming a
core-in-sheath composite, the polyester multifilament having a
difference in intrinsic viscosity between the core component and
the sheath component of 0.20 to 1.00, a total fineness of 4 to 30
dtex, a single-yarn fineness of 1.0 to 5.0 dtex, a breaking
strength of 5.0 to 9.0 cN/dtex, a fracture elongation of 12 to 45%,
a degree of interlacement of 2.0 to 15.0/m, and a number of
filaments of 3 to 15.
2. The polyester multifilament according to claim 1, wherein the
high-viscosity polyester as the core component has an intrinsic
viscosity of 0.70 to 1.50, and the low-viscosity polyester as the
sheath component has an intrinsic viscosity of 0.40 to 0.70.
Description
TECHNICAL FIELD
[0001] This disclosure relates to a high-strength fine-denier
multifilament that is excellent in weaving properties and wear
resistance and can be used in particular in a high-density thin
woven fabric suitable for use with athletic and outdoor
clothing.
BACKGROUND
[0002] Until now, many high-density woven fabrics made of synthetic
fiber multifilaments such as those of polyesters and nylons have
been proposed mainly for uses such as athletic clothing and
airbags. Along with the sophistication of uses, there has been a
demand for lighter woven fabrics, that is, thinner woven fabrics
and, accordingly, higher-strength woven fabrics. In particular, in
athletic and outdoor clothing, there is an increasing demand for
improved durability against active movements, and woven fabrics
have been desired to have improved wear resistance.
[0003] In Japanese Patent Laid-open Publication No. 2009-074213
(paragraph numbers [0008] to [0009]), a single-component polyester
multifilament woven fabric is proposed. The single-component
polyester multifilament woven fabric has high strength because it
contains polyethylene terephthalate having an intrinsic viscosity
of 0.70 to 1.20, and has improved weaving properties because it
contains 0.3 to 0.8 wt % of titanium oxide containing 60% or more
of particles having a primary particle diameter of 0.1 to 0.6 .mu.m
based on the total number of titanium oxide particles.
[0004] In addition, to have a thin woven fabric, it is required to
reduce the total fineness of the yarn, and the number of
constituent filaments of the yarn is inevitably reduced. Therefore,
the filaments are interlaced with difficulty, and the polyester
multifilament has poor convergence. Poor convergence deteriorates
the process passability in the production process, and makes
handling during warping and weaving difficult. In addition, because
of insufficient convergence, filament breakage (separation into
single yarns) may occur, the working of the warp during weaving may
be deteriorated, and warp breakage may easily occur. Warp breakage
not only merely stops the loom, but also requires a large amount of
labor to reconnect and restore the warp, and may greatly and
inconveniently reduce productivity. Also, in respect of the woven
fabric quality, filament breakage may cause streak-like defects. In
Japanese Patent Laid-open Publication No. 2009-013511 (paragraph
numbers [0008] to [0009]), to provide a polyamide multifilament
excellent in convergence, it is proposed to reduce the single-yarn
fineness to 0.8 dtex or less to facilitate interlacing in spite of
a small total fineness of 6 to 18 dtex, thereby making the degree
of interlacement 25 or more.
[0005] In Japanese Patent Laid-open Publication No. 2003-213528
(paragraph numbers [0013] to [0014]), a polyester monofilament for
screen gauze is proposed. The polyester monofilament is a
core-in-sheath composite yarn, a polyester used in the core
component has a limiting viscosity of 0.70 or more so that the
monofilament may have high strength, and a polyester used in the
sheath component has a limiting viscosity lower by 0.15 to 0.30
than that of the polyester used in the core component to suppress
scum (improve the wear resistance).
[0006] The single-component polyester disclosed in JP '213,
however, has a problem in wear resistance, and hardly meets the
demand for durability in sophisticated uses.
[0007] In JP '511, the weaving properties are indeed greatly
improved by increasing the degree of interlacement to improve the
convergence. The small single-yarn fineness, however, may cause
problems such as breakage of warp and weft during weaving as well
as generation of fluff.
[0008] As for JP '528, it is difficult to make the monofilament
into a high-density woven fabric, and the monofilament is
unsuitable for use in clothing because a cloth made of the
monofilament has high rigidity due to the high single-yarn
fineness. Moreover, when the core-in-sheath composite yarn
technique is applied to a fine-denier multifilament, a
core-in-sheath composite yarn having a small single-yarn fineness
may inconveniently cause sheath breakage or may be excessively
thinned in the sheath part so that sufficient wear resistance may
not be ensured. On the contrary, in a core-in-sheath composite yarn
having a large single-yarn fineness, due to the small number of
filaments, the filaments are interlaced with difficulty, the
core-in-sheath composite yarn has poor convergence, and the weaving
properties and woven fabric quality are deteriorated.
[0009] In other words, it is difficult with conventional techniques
to obtain a polyester multifilament for thin woven fabrics that
combine durability, weaving properties, and woven fabric quality
required in sophisticated uses. Therefore, development of a
high-strength fine-denier polyester multifilament having excellent
wear resistance and convergence is desired.
[0010] It could therefore be helpful to provide a high-strength
fine-denier polyester multifilament having excellent wear
resistance and convergence for the purpose of providing a
high-density thin woven fabric that combines excellent durability,
weaving properties, and woven fabric quality and is suitable for
use with athletic and outdoor clothing.
SUMMARY
[0011] We thus provide: [0012] The polyester multifilament
contains: a high-viscosity polyester as a core component; and a
low-viscosity polyester as a sheath component, the core component
and the sheath component forming a core-in-sheath composite, and
the polyester multifilament has a difference in intrinsic viscosity
between the core component and the sheath component of 0.20 to
1.00, a total fineness of 4 to 30 dtex, a single-yarn fineness of
1.0 to 5.0 dtex, a breaking strength of 5.0 to 9.0 cN/dtex, a
fracture elongation of 12 to 45%, a degree of interlacement of 2.0
to 15.0/m, and a number of filaments of 3 to 15. [0013] Further,
the polyester multifilament is characterized in that the
high-viscosity polyester as the core component has an intrinsic
viscosity of 0.70 to 1.50, and the low-viscosity polyester as the
sheath component has an intrinsic viscosity of 0.40 to 0.70.
[0014] The high-strength polyester multifilament has excellent wear
resistance and convergence, and is capable of providing a
high-density thin woven fabric that combines excellent durability,
weaving properties, and woven fabric quality suitable for use with
athletic and outdoor clothing.
DETAILED DESCRIPTION
[0015] Our polyester multifilament will be described.
[0016] The polyester multifilament is made of a core-in-sheath
composite fiber in which, in a cross section of a single yarn, a
core component and a sheath component are arranged such that the
core component is covered with the sheath component and the core
component is not exposed to the surface of the polyester
multifilament. In general, to increase the strength of a polyester
fiber, it is known that drawing at a high draw ratio is required in
the production process of an original yarn for high orientation and
high crystallization. In weaving a high-density thin woven fabric,
since a yarn having a small total fineness is woven at high
density, the warp is subjected to intense abrasion with a reed
under a heavy load so that fluff due to single yarn breakage may be
generated. Further, thin woven fabrics used in sophisticated uses
are required to have durability against friction, and it is an
important issue to improve the wear resistance of the original
yarn.
[0017] In the polyester multifilament, from the viewpoint of
obtaining excellent wear resistance, the polyester used in the
sheath component is required to have an intrinsic viscosity lower
than that of the core component polyester, and the difference in
intrinsic viscosity is preferably 0.20 to 1.00. A difference in
intrinsic viscosity of 0.20 or more can suppress the degree of
orientation and degree of crystallinity of the sheath component
polyester, that is, the polyester at the fiber surface of the
polyester multifilament, and can provide satisfactory wear
resistance. In addition, since the sheath component bears the shear
stress at the inner wall surface of the discharge hole of the melt
spinning spinneret, the core component receives weak shear force,
has a low degree of molecular chain orientation, and is spun in a
uniform state. Therefore, the finally obtained polyester
multifilament has improved strength. Meanwhile, for the polyester
multifilament to have high strength, the sheath component is also
required to be moderately oriented. Therefore, if the difference in
intrinsic viscosity is larger than 1.00, a satisfactory original
yarn strength is not obtained. A more preferable difference in
intrinsic viscosity of the polyester is 0.30 to 0.70.
[0018] The high-viscosity polyester as the core component used in
the polyester multifilament preferably has an intrinsic viscosity
of 0.70 to 1.50. An intrinsic viscosity of 0.70 or more enables
production of a polyester multifilament combining sufficient
strength and elongation. A more preferable intrinsic viscosity is
0.80 or more. The upper limit of the intrinsic viscosity is
preferably 1.50 or less from the viewpoint of ease of molding such
as melt extrusion. In consideration of production cost, the
reduction in molecular weight due to molecular chain scission
caused by heat or shear force in the production process, and the
melt flow stability, the upper limit of the intrinsic viscosity is
more preferably 1.20 or less.
[0019] Meanwhile, an intrinsic viscosity of the low-viscosity
polyester as the sheath component of 0.40 or more provides stable
yarn-making properties. A more preferable intrinsic viscosity is
0.50 or more. Further, the intrinsic viscosity is preferably 0.70
or less to obtain satisfactory wear resistance.
[0020] The polyester used in the polyester multifilament may be a
polyester containing polyethylene terephthalate (hereinafter
referred to as PET) as a main component.
[0021] PET be a polyester containing terephthalic acid as a main
acid component and ethylene glycol as a main glycol component, and
containing 90 mol % or more of ethylene terephthalate repeating
units. PET may, however, contain other copolymer components capable
of forming an ester bond in a proportion of less than 10 mol %.
Examples of such copolymer components include, as an acid
component, bifunctional aromatic carboxylic acids such as
isophthalic acid, phthalic acid, dibromoterephthalic acid,
naphthalene dicarboxylic acid, and o-ethoxybenzoic acid,
bifunctional aliphatic carboxylic acids such as sebacic acid,
oxalic acid, adipic acid, and dimer acid, and dicarboxylic acids
such as cyclohexanedicarboxylic acid, and as a glycol component,
ethylene glycol, diethylene glycol, propanediol, butanediol,
neopentyl glycol, bisphenol A, cyclohexane dimethanol, and
polyoxyalkylene glycols such as polyethylene glycol and
polypropylene glycol, but the copolymer components are not limited
thereto.
[0022] In addition, PET may contain, as additives, titanium dioxide
as a matting agent, silica or alumina fine particles as a
lubricant, a hindered phenol derivative as an antioxidant, and
further, a flame retardant, an antistatic agent, an ultraviolet
absorber, a coloring pigment, and the like as required.
[0023] PET in the core component is mainly responsible for the
strength of the polyester multifilament. Therefore, the amount of
an inorganic particle additive usually added to a polyester fiber,
which is typified by titanium oxide, is preferably 0.5 wt % or
less. Meanwhile, PET in the sheath component is mainly responsible
for the wear resistance of the polyester multifilament. Therefore,
it is preferable to add inorganic particles typified by titanium
oxide in an amount of about 0.1 wt % to 0.5 wt % to the sheath
component.
[0024] Next, the cross-sectional shape of the polyester
multifilament will be described.
[0025] As described above, the polyester multifilament is a
core-in-sheath composite polyester multifilament in which, in a
cross section of a single yarn, the core component and the sheath
component are arranged such that the core component is covered with
the sheath component and the core component is not exposed to the
surface of the polyester multifilament. In the "core-in-sheath"
composite polyester multifilament, it is only required that the
core component be completely covered with the sheath component, and
it is not necessarily required that the core component and the
sheath component be concentrically arranged. The polyester
multifilament may have any of number of cross-sectional shapes such
as round, flat, triangular, square, and pentagonal cross-sectional
shapes. In view of ease of achieving stable yarn-making properties
and high-order processability as well as densification of a woven
fabric, a round cross-sectional shape is preferable.
[0026] Since both the core component and the sheath component
contain a polyester, a phenomenon of delamination at a composite
interface, which frequently occurs in polyester/nylon composite
yarns, is unlikely to occur. However, in view of achieving both an
effect of improving the wear resistance exerted by the sheath
component and increase of the strength by the core component, the
composite ratio of core component:sheath component is preferably
60:40 to 95:5, and is more preferably 70:30 to 90:10.
[0027] The "composite ratio" refers to, in a cross-sectional
photograph of a single yarn of the polyester multifilament, a
cross-sectional area ratio between two types of polyesters
constituting the single yarn.
[0028] The polyester multifilament is required to have a total
fineness of 4 to 30 dtex. A total fineness of 4 dtex or more
enables stable yarn making and weaving, whereas a total fineness of
30 dtex or less may provide a desired high-density thin woven
fabric. A preferable range of the total fineness is 8 to 25
dtex.
[0029] The polyester multifilament is required to have a
single-yarn fineness of 1.0 to 5.0 dtex. If the single-yarn
fineness is less than 1.0 dtex, it is difficult to form a desired
core-in-sheath cross section, and sheath breakage tends to occur or
the sheath component tends to have a small thickness so that the
polyester multifilament may have insufficient wear resistance.
Moreover, the process passability such as yarn-making properties
and weaving properties also tends to deteriorate. A single-yarn
fineness of 5.0 dtex or less may facilitate interlacing and improve
convergence, and may provide an effect of improving process
passability and weaving properties. Moreover, the obtained woven
fabric has a satisfactory texture without being too hard while
maintaining denseness. A preferable range of the single-yarn
fineness is 1.5 to 3.0 dtex. To achieve a single-yarn fineness in
the above-mentioned range, in the method of producing a polyester
multifilament, the discharge amount and the spinneret are required
to be appropriately changed.
[0030] Further, the polyester multifilament is required to have a
number of filaments of 3 to 15. A number of filaments of 3 or more
may facilitate interlacing. Moreover, since an increased number of
filaments can distribute the contact with a reed or a guide during
weaving among single yarns, the load of friction applied to a
single yarn can be reduced, and the wear resistance of the original
yarn and the durability of the woven fabric are greatly improved.
The upper limit of the number of filaments depends on the total
fineness and single-yarn fineness, but is 15 or less.
[0031] The polyester multifilament is required to have improved
convergence to achieve excellent weaving properties and woven
fabric quality. If the convergence is insufficient, filament
breakage (separation into single yarns) may occur, the working of
the warp during weaving may be deteriorated, and the warp breakage
may easily occur. Also in respect of the woven fabric quality,
filament breakage may cause streak-like woven fabric defects.
[0032] The polyester multifilament is required to have a degree of
interlacement of 2.0 to 15.0/m, the degree of interlacement
representing the number of interlacements per meter. If the degree
of interlacement is less than 2.0/m, weaving properties tend to
deteriorate, that is, warp breakage may occur. The obtained woven
fabric tends to have streak-like woven fabric defects due to
filament breakage, and tends to be poor in the woven fabric
quality. A degree of interlacement of 2.0/m or more may provide
excellent weaving properties and woven fabric quality. Meanwhile,
if the degree of interlacement is too high, the polyester
multifilament has too many constraint points, and the
above-mentioned effect of distributing the contact with a reed or a
guide during weaving among single yarns to reduce the load of
friction applied to a single yarn may be reduced and, therefore,
the wear resistance of the original yarn and the durability of the
woven fabric tend to deteriorate. Therefore, the degree of
interlacement is required to be 15.0/m or less. Further, when the
degree of interlacement is further increased, the load in the
interlacing step increases, yarn breakage frequently occurs, and
the productivity may be reduced. A more preferable degree of
interlacement is 4.0 to 10.0/m.
[0033] The polyester multifilament having a breaking strength of
5.0 cN/dtex or more may have sufficient mechanical properties even
when being made into a thin woven fabric. The breaking strength is
more preferably 6.0 cN/dtex or more. In addition, the orientation
and degree of crystallinity are required to be suppressed from the
viewpoint of wear resistance. Therefore, the breaking strength is
9.0 cN/dtex or less, more preferably 8.0 cN/dtex or less.
[0034] Further, the polyester multifilament having a fracture
elongation of 12% or more can suppress yarn breakage and generation
of fluff during the weaving, and is excellent in handleability. The
polyester multifilament having a fracture elongation of 45% or less
may have a desired breaking strength. A more preferable range of
the fracture elongation is 17 to 35%.
[0035] Further, as for the strength at 5% elongation (5% Mo) and
the strength at 10% elongation (10% Mo) of the polyester
multifilament, from the viewpoint of dimensional stability of the
woven fabric, the 5% Mo is preferably 3.5 cN/dtex or more, more
preferably 3.8 cN/dtex or more. The 10% Mo is preferably 4.0
cN/dtex or more, more preferably 4.5 cN/dtex or more. In addition,
to suppress the orientation and degree of crystallinity from the
viewpoint of wear resistance, the 5% Mo is preferably 6.0 cN/dtex
or less, more preferably 5.0 cN/dtex or less. The 10% Mo is
preferably 8.0 cN/dtex or less, more preferably 7.0 cN/dtex or
less.
[0036] Next, a preferable method of producing the polyester
multifilament will be described.
[0037] A feature of the method of producing a polyester
multifilament is that the position at which the filaments are
interlaced is after drawing. When the filaments are subjected to
interlacing at the stage of an undrawn yarn, it is difficult to
interlace the filaments in the ranges of the total fineness,
single-yarn fineness, and number of filaments of the multifilament.
Therefore, interlacing the filaments at the stage after drawing, at
which the single-yarn fineness is reduced, can achieve a desired
degree of interlacement.
[0038] In addition, in the method of interlacing the filaments in
the polyester multifilament, a known interlacing nozzle can be
used. The compressed air pressure in the interlacement is
preferably 0.10 to 0.40 MPa. If the compressed air pressure is less
than 0.10 MPa, it is difficult to sufficiently interlace the
filaments, whereas if the compressed air pressure exceeds 0.40 MPa,
yarn breakage frequently occurs, and the productivity may be
reduced. The compressed air pressure is more preferably 0.15 to
0.30 MPa.
[0039] The method of spinning the polyester multifilament is not
particularly limited, and the polyester multifilament can be spun
according to a known technique. For example, high-viscosity PET as
a core component and low-viscosity PET as a sheath component are
each melt-extruded and sent to a predetermined composite pack using
a composite spinning machine, both the polymers are filtered in the
pack and then bonded together in a core-in-sheath form and
subjected to composite spinning with a spinneret, and a yarn
discharged from the spinneret is taken up to produce an undrawn
yarn. The undrawn yarn may be subjected to a two-step method in
which the undrawn yarn is wound up once and then drawn in a drawing
machine, or a one-step method in which the undrawn yarn is
continuously drawn without being wound up once. The two-step method
is more preferable because, in the interlacing described later, the
filaments are hardly interlaced if the yarn speed is high.
[0040] The method of drawing the polyester multifilament is not
particularly limited, and the polyester multifilament can be drawn
according to a known technique. For example, the drawing method can
be suitably selected from a method of performing one-stage hot
drawing between a first hot roll and a second hot roll, a method of
performing one-stage hot drawing with a first hot roll, an unheated
roll, and a hot plate between the rolls, a method of performing the
first stage hot drawing between a first hot roll and a second hot
roll and performing the second stage hot drawing between the second
hot roll and a third hot roll and the like. In particular, to
achieve high strength, it is required to draw an undrawn yarn at a
high draw ratio. When an undrawn yarn is drawn in one-stage
drawing, however, high drawing tension is applied so that problems
such as increased yarn unevenness and frequent yarn breakage may
occur. Therefore, it is preferable to draw an undrawn yarn in two
or more stages.
[0041] Further, as for the drawing temperature of the polyester
multifilament, in one-stage drawing, it is preferable that the
first hot roll usually have a temperature of (glass transition
temperature of the high-viscosity PET as the core component)+10 to
30.degree. C., and the second hot roll or the hot plate have a
temperature of 130 to 230.degree. C. A temperature of the second
hot roll or the hot plate of 130.degree. C. or more controls the
orientation, promotes the crystallization of the fiber, and
increases the strength. Meanwhile, a temperature of the second hot
roll or the hot plate of 230.degree. C. or less prevents fusion at
the hot roll or the hot plate, and provides satisfactory
yarn-making properties. In multi-stage drawing, it is preferable
that the first hot roll have a temperature of (glass transition
temperature of the high-viscosity PET as the core component)+10 to
30.degree. C., the second and subsequent hot rolls have gradually
increased temperatures, and the last hot roll have a temperature of
100 to 230.degree. C.
[0042] Further, the polyester multifilament is preferably drawn at
a draw ratio of 3.0 to 7.0 in total. The draw ratio is more
preferably 3.5 to 6.0, still more preferably 3.8 to 5.0.
EXAMPLES
[0043] Hereinafter, the polyester multifilament will be
specifically described with reference to examples. The measured
values in the examples were measured by the following methods.
(1) Intrinsic Viscosity (IV)
[0044] The relative viscosity .eta.r defined by .eta./.eta..sub.0
was determined according to the following mathematical formula at a
temperature of 25.degree. C. using an Ostwald viscometer by
dissolving 0.8 g of a sample polymer in 10 mL of o-chlorophenol
(hereinafter abbreviated as "OCP") having a purity of 98% or more
at a temperature of 25.degree. C. to prepare a polymer solution.
The intrinsic viscosity (IV) was calculated from .eta.r according
to the following mathematical formula:
.eta.r=.eta./.eta..sub.0=(t.times.d)/(t.sub.0.times.d.sub.0)
Intrinsic viscosity (IV)=0.0242.eta.r+0.2634.
In the formula, .eta. is the viscosity of the polymer solution,
.eta..sub.0 is the viscosity of OCP, t is the dropping time of the
solution (sec), d is the density of the solution (g/cm.sup.3), to
is the dropping time of OCP (sec), and do is the density of OCP
(g/cm.sup.3).
(2) Total Fineness (Dtex)
[0045] A yarn was wound up into a 500-m skein, and a value obtained
by multiplying the mass (g) of the skein by 20 was defined as the
fineness.
(3) Breaking Strength (cN/Dtex), Fracture Elongation (%), and
Strength (Modulus) at 5% Elongation (cN/Dtex) and Strength
(Modulus) at 10% Elongation (cN/Dtex)
[0046] The breaking strength, fracture elongation, and strength at
5% elongation and strength at 10% elongation were measured
according to JIS L1013 (1999) using TENSILON UCT-100 manufactured
by ORIENTEC CORPORATION.
(4) Degree of Interlacement (Number/m)
[0047] A yarn was floated on water, and the number of convergence
points per meter was counted as the degree of interlacement. The
number was counted 10 times, and the average of the counted numbers
was calculated.
(5) Wear Resistance of Original Yarn
[0048] A yarn was subjected to a yarn tension of 0.9 g/dtex, a flat
part of a reed (material: SK material, 7 mm in width.times.50 mm in
length.times.50 .mu.m in thickness) was pressed against the yarn at
a contact angle of 20.degree., and the yarn subjected to a
reciprocating motion at a stroke length of 30 mm and a speed of 670
times/min for 10 minutes. The treated yarn was magnified and
observed with a microscope. The wear resistance of the original
yarn was evaluated as "A" when no fluff or fibrillation (surface
fraying) was observed, and evaluated as "C" when fluff or
fibrillation was observed.
(6) Evaluation of Weaving Properties and Weaving Quality
[0049] A fabric was woven so that the fabric may have a basis
weight of 30 to 35 g/m.sup.2 by adjusting the basis weight using a
water jet loom according to the total fineness of the filaments
used. The weaving properties were evaluated as "S" when the number
of loom stoppages per 100 m due to yarn breakage or the like was
less than 3 times, "A" when the number of loom stoppages was 3
times or more and less than 10 times, and "C" when the number of
loom stoppages was 10 times or more. The weaving quality was
evaluated by counting the total number of defects such as fluff and
filament breakage. The weaving quality was evaluated as "S" when
the total number of defects was less than 3 per 100 m, "A" when the
total number of defects was 3 or more and less than 10, and "C"
when the total number of defects was 10 or more.
(7) Wear Resistance of Fabric
[0050] The wear resistance of the fabric was measured according to
JIS L1096 (2010), method E (Martindale method). The test was
performed under the conditions of a polyester standard friction
cloth and a pressing load of 9 kPa. The judgment was made according
to the number of friction cycles before the generation of fluff.
The wear resistance of the fabric was evaluated as "A" when the
number of friction cycles was 5,000 times or more, "B" when the
number of friction cycles was 3,000 times or more and less than
5,000 times, and "C" when the number of friction cycles was less
than 3,000 times.
[0051] As for the production methods in the Examples and
Comparative Examples, polyester filaments were obtained under the
production conditions shown in Tables 1 to 3 according to a known
technique.
Example 1
[0052] PET having an intrinsic viscosity of 0.80 as a core
component and PET having an intrinsic viscosity of 0.50 as a sheath
component were melted at a temperature of 295.degree. C. using an
extruder type extrusion machine. Then, the polymers were metered
with a pump at a polymer temperature of 290.degree. C. so that the
composite ratio might be core component:sheath component=80:20, and
allowed to flow into a known composite spinneret having five holes
arranged in a core-in-sheath structure. A yarn discharged from the
spinneret was wound up once at a spinning speed of 1,200 m/min, and
then drawn with a known drawing device between a first hot roll
heated to 90.degree. C. and a second hot roll heated to 130.degree.
C. at a draw ratio of 4.2 and heat-set. The obtained drawn yarn was
interlaced with an interlacing nozzle disposed between a final roll
and a winder at an interlacing pressure of 0.23 MPa, and then wound
up at 800 m/min. No particular problem was found in yarn-making
properties, and a polyester multifilament having a total fineness
of 12.0 dtex, a single-yarn fineness of 2.4 dtex, a breaking
strength of 6.5 cN/dtex, a fracture elongation of 17.7%, and a
degree of interlacement of 5.8/m was obtained. The polyester
multifilament had satisfactory wear resistance of the original
yarn. Other physical properties of the original yarn are shown in
Table 1.
[0053] Using the polyester multifilament, a fabric was woven with a
water jet loom so that the fabric might have a basis weight of 30
g/m.sup.2. No yarn breakage occurred during 100 m of weaving, and
the polyester multifilament had very satisfactory weaving
properties. The obtained fabric was free from defects such as
fluff, and had a very satisfactory weaving quality. In addition,
the wear resistance of the fabric was satisfactory, and no fluff
was generated even after a number of friction cycles of 6,000
times.
Examples 2 and 3
[0054] A polyester multifilament was obtained in the same manner as
in Example 1 except that the draw ratio was changed to 3.9 and 3.6,
respectively. The original yarn of the obtained polyester
multifilament had physical properties as shown in Table 1. In each
of Examples 2 and 3, no yarn breakage occurred during 100 m of
weaving, and the polyester multifilament had very satisfactory
weaving properties. The obtained fabric was free from defects such
as fluff, and had a very satisfactory weaving quality. In addition,
the wear resistance of the fabric was satisfactory, and no fluff
was generated even after a number of friction cycles of 6,000
times.
Examples 4 and 5 and Comparative Examples 1 and 2
[0055] A polyester multifilament was obtained in the same manner as
in Example 1 except that the interlacing pressure was changed to
0.08 to 0.42 MPa. The original yarn of the obtained polyester
multifilament had physical properties as shown in Table 1. In
Example 4, the degree of interlacement was 9.9/m, and satisfactory
results were obtained as in Example 1 as for the wear resistance of
the original yarn, weaving properties, weaving quality, and wear
resistance of the fabric. In Example 5, the degree of interlacement
was 4.2/m, and the polyester multifilament had slightly lower
convergence than that of Example 1. Therefore, 3 times of yarn
breakage occurred during 100 m of weaving, but the polyester
multifilament had satisfactory weaving properties. Although no
fluff was observed in the obtained fabric, defects of filament
breakage were observed, and the fabric was slightly inferior to
that of Example 1. In Comparative Example 1, the interlacing
pressure was high, the yarn swayed largely at an interlacing
position, and yarn breakage occurred. The degree of interlacement
was as high as 15.3/m. The wear resistance of the original yarn was
lower than that in Example 1, and the polyester multifilament
easily generated fluff. During weaving, 6 times of yarn breakage
occurred. The weaving quality was lower than that in Example 1 and
fluff was observed. As for the wear resistance of the fabric, fluff
was generated even after a number of friction cycles of 3,500
times. In Comparative Example 2, the interlacing pressure was low.
The degree of interlacement was 1.7/m, and the filaments were
insufficiently interlaced. During weaving, warp breakage frequently
occurred, and loom stoppages occurred every few meters. As for the
weaving quality, filament breakage frequently occurred, and many
streak-like defects were observed.
TABLE-US-00001 TABLE 1 Comparative Comparative Example 1 Example 2
Example 3 Example 4 Example 5 Example 1 Example 2 High-viscosity
Intrinsic viscosity 0.80 0.80 0.80 0.80 0.80 0.80 0.80 component
(core component) Low-viscosity Intrinsic viscosity 0.50 0.50 0.50
0.50 0.50 0.50 0.50 component (sheath component) Difference in Core
component- 0.30 0.30 0.30 0.30 0.30 0.30 0.30 intrinsic viscosity
sheath component Composite ratio Core component: 80:20 80:20 80:20
80:20 80:20 80:20 80:20 sheath component Production method Two-step
Two-step Two-step Two-step Two-step Two-step Two-step method method
method method method method method Spinning speed [m/min] 1200 1200
1200 1200 1200 1200 1200 Draw ratio [times] 4.2 3.9 3.6 4.2 4.2 4.2
4.2 Interlacing position After drawing After drawing After drawing
After drawing After drawing After drawing After drawing Single-yarn
fineness at interlacing 2.4 2.4 2.4 2.4 2.4 2.4 2.4 position [dtex]
Compressed air pressure in 0.23 0.23 0.23 0.30 0.15 0.42 0.08
interlacement [MPa] Total fineness [dtex] 12.0 12.0 12.0 12.0 12.0
12.0 12.0 Single-yarn fineness [dtex] 2.4 2.4 2.4 2.4 2.4 2.4 2.4
Number of filaments 5 5 5 5 5 5 5 Breaking strength [cN/dtex] 6.5
6.0 5.5 6.4 6.4 6.4 6.5 Fracture elongation [%] 17.7 24.6 31.7 17.2
17.2 17.2 17.3 Strength at 5% elongation [cN/dtex] 5.0 4.3 3.6 5.0
5.0 5.0 5.0 Strength at 10% elongation [cN/dtex] 5.9 5.4 4.2 5.9
5.9 5.9 5.9 Degree of interlacement [number/m] 5.8 5.9 5.8 9.9 4.2
15.3 1.7 Wear resistance of original yarn A A A A A C A Weaving
properties S S S S A A C Weaving quality S S S S A A C Wear
resistance of fabric A A A A A B A
Comparative Example 3
[0056] A polyester multifilament was obtained in the same manner as
in Example 1 except that the interlacing position was changed to
before winding of the spun yarn. The physical properties of the
original yarn of the obtained polyester multifilament were as shown
in Table 2. The degree of interlacement was 0.8/m, and the
filaments were insufficiently interlaced. During weaving, warp
breakage frequently occurred, and loom stoppages occurred every few
meters. As for the weaving quality, filament breakage frequently
occurred, and many streak-like defects were observed.
Examples 6 to 8 and Comparative Examples 4 and 5
[0057] A polyester multifilament was obtained in the same manner as
in Example 2 except that the discharge amount and the number of
holes of the spinneret were adjusted to change the total fineness,
single-yarn fineness, and number of filaments. The physical
properties of the original yarn of the obtained polyester
multifilament were as shown in Table 2. In Examples 6 to 8, the
physical properties of the original yarn, weaving properties,
weaving quality, and wear resistance of the fabric were comparable
to those in Example 2. In Comparative Example 4, since the
single-yarn fineness was as large as 5.6 dtex, the degree of
interlacement was 1.2/m, and the filaments were insufficiently
interlaced. During weaving, warp breakage frequently occurred, and
loom stoppages occurred every few meters. As for the weaving
quality, filament breakage frequently occurred, and many
streak-like defects were observed. Moreover, the obtained fabric
had a rough texture. In Comparative Example 5, single yarn breakage
frequently occurred during spinning, and single yarn wrapping
frequently occurred during drawing. The obtained polyester
multifilament had a single-yarn fineness as small as 0.8 dtex, and
thus the degree of interlacement was as high as 18.8/m. The
polyester multifilament after the wear test of the original yarn
had a large amount of fluff, and poor wear resistance. In addition,
when the obtained polyester multifilament was subjected to weaving,
warp breakage frequently occurred and no fabric was woven.
Comparative Example 6
[0058] A polyester monofilament was obtained in the same manner as
in Example 1 except that the number of holes of the spinneret was
changed to one to change the discharge amount, and no interlacing
nozzle was used. The physical properties of the original yarn of
the obtained polyester monofilament are shown in Table 2. The
obtained polyester monofilament frequently caused both warp
breakage and weft breakage in a water jet loom, and no fabric was
woven.
TABLE-US-00002 TABLE 2 Comparative Comparative Comparative
Comparative Example 3 Example 6 Example 7 Example 8 Example 4
Example 5 Example 6 High-viscosity Intrinsic viscosity 0.80 0.80
0.80 0.80 0.80 0.80 0.80 component (core component) Low-viscosity
Intrinsic viscosity 0.50 0.50 0.50 0.50 0.50 0.50 0.50 component
(sheath component) Difference in Core component- 0.30 0.30 0.30
0.30 0.30 0.30 0.30 intrinsic viscosity sheath component Composite
ratio Core component: 80:20 80:20 80:20 80:20 80:20 80:20 80:20
sheath component Production method Two-step Two-step Two-step
Two-step Two-step Two-step Two-step method method method method
method method method Spinning speed [m/min] 1200 1200 1200 1200
1200 1200 1200 Draw ratio [times] 4.2 3.9 3.9 3.9 3.9 3.9 4.2
Interlacing position Spun yarn After drawing After drawing After
drawing After drawing After drawing -- Single-yarn fineness at
interlacing 10.1 2.2 1.9 1.6 5.6 0.8 -- position [dtex] Compressed
air pressure in 0.23 0.23 0.23 0.23 0.23 0.23 -- interlacement
[MPa] Total fineness [dtex] 12.0 21.7 28.1 8.2 28.2 12.0 9.8
Single-yarn fineness [dtex] 2.4 2.2 1.9 1.6 5.6 0.8 9.8 Number of
filaments 5 10 15 5 5 15 1 Breaking strength [cN/dtex] 6.2 6.1 6.0
6.4 5.8 6.1 6.3 Fracture elongation [%] 16.7 23.2 23.5 21.3 26.4
19.8 21.2 Strength at 5% elongation [cN/dtex] 4.9 4.2 4.2 4.4 4.0
4.6 3.9 Strength at 10% elongation [cN/dtex] 5.8 5.4 5.3 5.5 5.0
5.8 5.5 Degree of interlacement [number/m] 0.8 6.3 6.4 6.9 1.2 18.8
-- Wear resistance of original yarn A A A A A C A Weaving
properties C S S S C C C Weaving quality C S S S C -- -- Wear
resistance of fabric A A A A B -- --
Example 9
[0059] Spinning was performed in the same manner as in Example 1
except that PET having an intrinsic viscosity of 1.00 was used as a
core component and the spinning speed was adjusted to 600 m/min.
The yarn was wound up once, and then drawn in the same manner as in
Example 1 except that the yarn was subjected to two-stage drawing
with a known drawing device between first and second hot rolls
heated to 90.degree. C. and between the second hot roll and a third
hot roll heated to 200.degree. C. at a draw ratio of 4.5 and
heat-set, whereby a polyester multifilament was obtained. The
physical properties of the original yarn of the obtained polyester
multifilament were as shown in Table 3. During weaving, no yarn
breakage occurred over 100 m, and the polyester multifilament had
very satisfactory weaving properties. The obtained fabric was free
from defects such as fluff, and had a very satisfactory weaving
quality. In addition, the wear resistance of the fabric was
satisfactory, and no fluff was generated even after a number of
friction cycles of 6,000 times.
Example 10
[0060] A polyester multifilament was obtained in the same manner as
in Example 9 except that PET having an intrinsic viscosity of 1.25
was used as a core component and the spinning speed and the draw
ratio were adjusted to 500 m/min and 5.8, respectively. The
physical properties of the original yarn of the obtained polyester
multifilament are shown in Table 3. As for the wear resistance of
the original yarn, no fluff or fibrillation was observed, but 8
times of warp breakage occurred during 100 m of weaving. The
quality of the obtained fabric was lower than in Example 1 and
fluff was observed. The wear resistance of the fabric was lower
than in Example 1, and fluff was generated after a number of
friction cycles of 4,500 times.
Comparative Example 7
[0061] PET having an intrinsic viscosity of 0.80 was used as a
single component, and melted at a temperature of 295.degree. C.
using an extruder type extrusion machine. Then, the polymer was
allowed to flow into a known single-component spinneret having five
holes at a polymer temperature of 290.degree. C. A yarn discharged
from the spinneret was wound up once at a spinning speed of 800
m/min, and then drawn with a known drawing device between a first
hot roll heated to 90.degree. C. and a second hot roll heated to
130.degree. C. at a draw ratio of 4.3 and heat-set. The obtained
drawn yarn was interlaced with an interlacing nozzle disposed
between a final roll and a winder at an interlacing pressure of
0.23 MPa, and then wound up at 800 m/min. The physical properties
of the original yarn of the obtained polyester multifilament were
as shown in Table 3. The wear resistance of the original yarn was
lower than that in Example 1, and the polyester multifilament
easily generated fluff. No yarn breakage occurred during 100 m of
weaving, and the polyester multifilament had very satisfactory
weaving properties. However, fluff was observed in the obtained
fabric, and the fabric was inferior to that of Example 1. In
addition, the wear resistance of the fabric was greatly lower than
in Example 1, and generation of fluff was observed after a number
of friction cycles of 500 times.
Example 11
[0062] PET having an intrinsic viscosity of 0.80 as a core
component and PET having an intrinsic viscosity of 0.50 as a sheath
component were used, and subjected to spinning and drawing in a
known direct spinning-drawing device. The polymers were melted at a
temperature of 295.degree. C. using an extruder type extrusion
machine. Then, the polymers were metered with a pump at a polymer
temperature of 290.degree. C. so that the composite ratio might be
core component:sheath component=80:20, and allowed to flow into a
known composite spinneret having five holes arranged in a
core-in-sheath structure. A yarn discharged from the spinneret was
taken up at a spinning speed of 1,300 m/min, and then drawn at a
draw ratio of 3.8 without being wound up once and heat-set. The
obtained drawn yarn was interlaced with an interlacing nozzle
disposed between a final roll and a winder at an interlacing
pressure of 0.23 MPa, and then wound up at 5,000 m/min. The
yarn-making properties were inferior to those in the two-step
method as in Example 1, and yarn breakage was observed at the
interlaced portion. The physical properties of the original yarn of
the obtained polyester multifilament are shown in Table 3. The
single-yarn fineness at the interlacing position after the drawing
was 2.4 dtex, which was comparable to that of Example 1. However,
the speed of the yarn passing through the interlacing nozzle was as
high as 5,000 m/min so that the degree of interlacement was as
small as 2.8/m. Since the degree of interlacement was inferior to
that of Example 1, the polyester multifilament had poor
convergence, and 7 times of yarn breakage occurred during 100 m of
weaving. Although no fluff was observed in the obtained fabric,
defects of filament breakage were observed, and the fabric was
slightly inferior to that of Example 1.
Comparative Example 8
[0063] A polyester multifilament was obtained in the same manner as
in Example 11 except that the interlacing position was changed to
before taking up the spun yarn. The physical properties of the
original yarn of the obtained polyester multifilament are shown in
Table 3. The degree of interlacement was 0.7/m, and the filaments
were insufficiently interlaced. During weaving, warp breakage
frequently occurred, and loom stoppages occurred every few meters.
As for the weaving quality, filament breakage frequently occurred,
and many streak-like defects were observed.
TABLE-US-00003 TABLE 3 Comparative Comparative Example 9 Example 10
Example 7 Example 11 Example 8 High-viscosity Intrinsic viscosity
1.00 1.25 0.80 0.80 0.80 component (core component) Low-viscosity
Intrinsic viscosity 0.50 0.50 -- 0.50 0.50 component (sheath
component) Difference in Core component- 0.50 0.75 -- 0.30 0.30
intrinsic viscosity sheath component Composite ratio Core
component: 80:20 80:20 100:0 80:20 80:20 sheath component
Production method Two-step method Two-step method Two-step method
One-step method One-step method Spinning speed [m/min] 600 500 800
1300 1300 Draw ratio [times] 4.5 5.8 4.3 3.8 3.8 Interlacing
position After drawing After drawing After drawing After drawing
Spun yarn Single-yarn fineness at interlacing 2.4 2.4 2.4 2.4 9.1
position [dtex] Compressed air pressure in 0.23 0.23 0.23 0.23 0.23
interlacement [MPa] Total fineness [dtex] 12.0 12.0 12.0 12.0 12.0
Single-yarn fineness [dtex] 2.4 2.4 2.4 2.4 2.4 Number of filaments
5 5 5 5 5 Breaking strength [cN/dtex] 7.4 8.5 5.6 6.1 6.0 Fracture
elongation [%] 18.6 13.6 33.2 20.6 19.8 Strength at 5% elongation
[cN/dtex] 4.8 5.7 3.2 3.9 3.9 Strength at 10% elongation [cN/dtex]
6.6 8.0 4.0 5.5 5.5 Degree of interlacement [number/m] 5.3 5.1 5.5
2.8 0.7 Wear resistance A A C A A of original yarn Weaving
properties S A S A C Weaving quality S A A A C Wear resistance of
fabric A B C A A
* * * * *