U.S. patent application number 16/915309 was filed with the patent office on 2020-10-15 for bulky yarn.
This patent application is currently assigned to Toray Industries, Inc.. The applicant listed for this patent is Toray Industries, Inc.. Invention is credited to Masato Masuda, Takashi Shibata, Hirofumi Yamanaka.
Application Number | 20200325601 16/915309 |
Document ID | / |
Family ID | 1000004928989 |
Filed Date | 2020-10-15 |
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United States Patent
Application |
20200325601 |
Kind Code |
A1 |
Masuda; Masato ; et
al. |
October 15, 2020 |
BULKY YARN
Abstract
An object of the present invention is to provide a bulky yarn
made of synthetic fibers, which is suppressed in tanglement between
filaments while having a loop shape in the surface layer thereof,
and has a soft texture and is light and excellent in heat retention
properties while being good in handleability in high-order
processing. The present invention provides a bulky yarn made of
synthetic fibers, including: a sheath yarn having a
three-dimensional crimped structure; and a core yarn twisted with
the sheath yarn to fix the sheath yarn, wherein the sheath yarn is
not substantially broken and continuously forms loops.
Inventors: |
Masuda; Masato; (Shizuoka,
JP) ; Shibata; Takashi; (Shizuoka, JP) ;
Yamanaka; Hirofumi; (Shizuoka, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Toray Industries, Inc. |
Tokyo |
|
JP |
|
|
Assignee: |
Toray Industries, Inc.
Tokyo
JP
|
Family ID: |
1000004928989 |
Appl. No.: |
16/915309 |
Filed: |
June 29, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15745559 |
Jan 17, 2018 |
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PCT/JP2016/071299 |
Jul 20, 2016 |
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16915309 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
D02G 3/36 20130101; D02G
3/34 20130101; D02G 3/42 20130101; D02G 1/162 20130101 |
International
Class: |
D02G 3/34 20060101
D02G003/34; D02G 3/42 20060101 D02G003/42; D02G 1/16 20060101
D02G001/16 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 22, 2015 |
JP |
2015-145017 |
Claims
1. A bulky yarn made of synthetic fibers, comprising: a sheath
yarn; and a core yarn twisted with the sheath yarn to fix the
sheath yarn, wherein the sheath yarn has a spiral structure with a
radius of curvature of 2 mm to 30 mm; by 10 sites randomly selected
from the single bulky yarn consisting of the sheath yarn and the
core yarn, and the textured yarn is photographed at a magnification
at which 10 or more sections from a twist point between the core
yarn and the sheath yarn to the next twist point (that is, each
section is one loop) can be recognized in the longitudinal
direction of the textured yarn, and observed for the determination
each of the 10 photographed images, the number of breaking points
of the sheath yarn per 1 mm of the bulky yarn was counted for 10
loops, and the average of the number of breaking points of the
loops was calculated, and the average was rounded off to the first
decimal place to give the number of breaking points of the loops
(number/mm), and the number of breaking points on average of the
total of 100 loops is 0.2/mm or less.
2. The bulky yarn according to claim 1, wherein the fibers that
constitute the bulky yarn have a single yarn fineness of 3.0 dtex
or more, the core yarn and the sheath yarn have a single yarn
fineness ratio (sheath/core) in a range of 0.5 to 2.0, the core
yarn and the sheath yarn have 1/mm to 30/mm twist points in a fiber
axis direction of the bulky yarn, and the crimped structure of the
sheath yarn has a radius of curvature of 2 mm to 30 mm.
3. The bulky yarn according to claim 1, wherein both or one of the
core yarn and the sheath yarn has a hollow rate of 20% or more, and
the bulky yarn have a single yarn fineness of 3.0 dtex or more.
4. The bulky yarn according to claim 1, wherein the core yarn and
the sheath yarn are monocomponent fibers of same type.
5. A textile product, comprising the bulky yarn according to claim
1 in at least part thereof.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a Divisional Application of U.S. Ser. No.
15/745,559, filed Jan. 17, 2018, which is the U.S. National Phase
application of PCT/JP2016/071299, filed Jul. 20, 2016, which claims
priority to Japanese Patent Application No. 2015-145017, filed Jul.
22, 2015, the disclosures of these applications being incorporated
herein by reference in their entireties for all purposes.
TECHNICAL FIELD OF THE INVENTION
[0002] The present invention relates to a bulky yarn made of
synthetic fibers, which includes a sheath yarn and a core yarn and
has a plurality of loops.
BACKGROUND OF THE INVENTION
[0003] Synthetic fibers made from thermoplastic polymers such as
polyesters and polyamides have features that they have good basic
characteristics such as mechanical properties and dimensional
stability, and are excellent in the balance of such
characteristics. Fiber materials based on these characteristics,
which are obtained by spinning and are made to have various
structural forms by high-order processing, are widely used not only
in clothing applications but also in interior, vehicle interior,
and industrial applications. It is no exaggeration to say that
technological innovation has been made on the development of new
techniques related to synthetic fibers based on a motivation to
simulate natural materials. Various technological proposals have
been made to make synthetic fibers develop functions derived from
natural complex structural forms. For example, some kind of
synthetic fibers are made to develop a special texture such as
squeaky touch and flexibility through simulation of a cross section
of silk. Another kind of synthetic fibers are made to develop a
special color through simulation of the Morpho butterfly or the
like. Moreover, water repellency is imparted to a fabric through
simulation of the lotus leaf. Moreover, there is an effort to
obtain a fiber structure having a soft texture and functions such
as lightweight and heat retention properties of natural down.
[0004] As the natural down, a mixture of down balls (in a granular
cotton form) collected in a small amount from the chest of
waterfowls and feathers (in a fluffy form) is generally used. These
materials are rich in the soft texture, easy to follow the body
shape, and very light, and develop excellent heat retention
properties owing to their special structural form formed of keratin
fibers. For this reason, functions of products including natural
feathers as batting have been recognized by even general users, and
the natural down is widely used in bedclothes and clothing items
such as jackets. Capture of waterfowls, however, is limited from
the viewpoint of nature conservation, and the total production of
natural down is restricted. Furthermore, due to the recent abnormal
weather and occurrence of the plague, there is a problem that the
supply of natural down largely fluctuates, and is also a problem of
price increase. In addition, despite the number of steps for the
use of natural down, such as collection, screening, disinfection,
and degreasing of the feathers, peculiar odor and animal allergy
are often at issue. Moreover, from the viewpoint of animal welfare,
there is also a movement to eliminate the use of natural down in
Europe and other countries. For this reason, attention is being
paid to a batting material made of synthetic fibers that is capable
of stable supply.
[0005] Many batting materials made of synthetic fibers have been
proposed from long ago, but there are no batting materials
comparable to natural down in terms of basic characteristics such
as the bulkiness, compression recovery, and soft texture.
[0006] Conventionally used yarn processing techniques intended for
adding high value to fibers have been generally known to be capable
of producing a bulky textured yarn by subjecting the fibers to real
twisting and then untwisting the fibers, or by mixing one or more
kinds of fibers with a fluid processing nozzle or the like, for
example. Since such bulky textured yarns are basically made of long
fibers, they can be processed into various forms, and can also be
applied to a batting material based on the bulkiness and soft
texture of the textured yarns.
[0007] Patent Document 1 discloses the following textured yarn.
First, of two kinds of fibers used, only one kind of the fibers are
supplied to a waist gauge while being swayed, and then the two
kinds of fibers are collectively subjected to real twisting to form
loops by the swayed fibers. After that, the fibers are untwisted by
further being scratched with two discs or the like to provide a
bulky textured yarn. The fibers are subjected to heat treatment at
the same time with or after the untwisting step, or sheath yarns
are fused to each other with a binder in order to strengthen the
fixing of the sheath yarns. Indeed, the method disclosed in Patent
Document 1 has a possibility of providing a bulky yarn having loops
of sheath yarns by adjusting the degree of yarn swaying or the like
in accordance with a conventional technique.
[0008] Patent Document 2 discloses a technique of injecting
compressed air to threads traveling inside an interlacing nozzle
from a direction perpendicular to the threads to open and tangle
the threads, so that the excessively supplied sheath yarns are
fixed by the difference in the yarn length. Similarly to Patent
Document 1, in Patent Document 2, it is possible to obtain a bulky
textured yarn including sheath yarns having loop shapes.
[0009] Such bulky yarns having loops suffer from tanglement between
fibers, which is generally recognized as "entanglement". The
entanglement is thought to cause poor unwinding in the high-order
processing, and to have an influence on the deterioration of the
texture of textile products and durability of textile products. For
this reason, attempts have been made to remedy the entanglement
starting from a fluid processed yarn.
[0010] Patent Document 3 discloses that a bulky fluid jet textured
yarn having a loop portion made of polytrimethylene terephthalate
(3GT) is less likely to suffer from entanglement owing to the
elasticity of the 3GT fibers.
PATENT DOCUMENTS
[0011] Patent Document 1: Japanese Patent Laid-open Publication No.
2011-246850 [0012] Patent Document 2: Japanese Patent Laid-open
Publication No. 2012-67430 [0013] Patent Document 3: Japanese
Patent Laid-open Publication No. 11-100740
SUMMARY OF THE INVENTION
[0014] In Patent Document 1 of the prior art described above, the
textured yarn can possibly be used as a batting material if the
binder is mixed in advance and the sheath yarns are fused to each
other after the processing to fix the loops. However, if loop yarns
from which the sheath yarns are partially protruded are subjected
to real twisting and the fibers are untwisted by scratching with
the rubber or the like of a mechanical kneading machine, the loops
may be partially broken or deteriorated. If the textured yarn is
used as the batting, eventually, several to several tens of the
yarns are bundled and filled. As a result, the sheath yarns are
broken in many portions to become fluff, and tangled with the
sheath yarns of the nearby textured yarn, so that there are cases
where the poor unwinding in the molding processing is caused or the
process passability in the molding processing is deteriorated.
Furthermore, since the sheath yarns are remarkably tangled with
each other between the textured yarns, when the textured yarns are
filled, the textured yarns give a feeling of a foreign body and
impair the texture. Another problem is that fusion and fixing of
the tangled portion gives a more remarkable feeling of a foreign
body.
[0015] According to the technique of Patent Document 2, in the case
of intermingling the traveling threads in the nozzle, and opening
and interlacing the fibers, the traveling threads sway in a very
short period to cause tanglement between them. For this reason,
small loops influenced by the nozzle shape are naturally
excessively formed with high frequency. In addition, since the
sheath yarn is randomly interlaced with the core yarn, the size of
the loops varies in the fiber axis direction, and the yarn is
insufficient in the bulkiness. Further, the loop yarns formed in
the nozzle stay inside the nozzle, and then discharged to the
outside of the nozzle by the injected air. For this reason, the
size of the loops and the length of the sheath yarns forming the
loops vary in the fiber axis direction of the textured yarn to form
slack. In this case, particularly a sheath yarn having slack tends
to be tangled with another sheath yarn, and there still remain
problems such as the process passability in the high-order
processing and that the portion where the sheath yarns are tangled
with each other leads to a feeling of a foreign body.
[0016] In the technique of Patent Document 3, the use of 3GT which
elastically elongates and deforms can possibly suppress the
entanglement while keeping the moderate resilience of the sheath
yarns, because the loops are compactly converged although the
sheath yarns have a difference in the yarn length. The loop is,
however, as small as about 0.6 mm at most. Moreover, if the number
of loops is increased for achieving the bulkiness, the density of
the sheath yarns increases, so that the sheath yarns tend to be
tangled with each other, and the entanglement cannot be suppressed
in some cases.
[0017] It is desired to provide a material for batting which solves
the conventional problems and is suppressed in tanglement between
textured yarns despite its high bulkiness and compression
recoverability comparable to those of natural down. The present
invention provides a bulky yarn which is good in handleability in
high-order processing, and has a soft texture and is light and
excellent in heat retention properties.
[0018] The above-mentioned objects may be achieved by the following
means.
[0019] 1. A bulky yarn made of synthetic fibers, including:
[0020] a sheath yarn having a three-dimensional crimped structure;
and
[0021] a core yarn twisted with the sheath yarn to fix the sheath
yarn,
[0022] wherein the sheath yarn is not substantially broken and
continuously forms loops.
[0023] 2. Preferable aspects of the bulky yarn include the
following.
[0024] The bulky yarn, wherein the core yarn and the sheath yarn
have a single yarn fineness ratio (sheath/core) in a range of 0.5
to 2.0,
[0025] the core yarn and the sheath yarn have 1/mm to 30/mm twist
points in a fiber axis direction of the bulky yarn, and
[0026] the crimped structure of the sheath yarn has a radius of
curvature of 2 mm to 30 mm.
[0027] 3. The bulky yarn according to either of the above items,
wherein the fibers that constitute the bulky yarn have a single
yarn fineness of 3.0 dtex or more, and
[0028] the bulky yarn has a coefficient of static friction between
fibers of 0.3 or less.
[0029] 4. The bulky yarn according to any one of the above items,
wherein the core yarn has a three-dimensional crimp.
[0030] 5. The bulky yarn according to any one of the above items,
wherein both or one of the core yarn and the sheath yarn is hollow
section fibers having a hollow rate of 20% or more.
[0031] 6. The bulky yarn according to any one of the above items,
wherein the core yarn and the sheath yarn are monocomponent fibers
of same type.
[0032] In addition, the following product can be mentioned as a
product including the bulky yarn.
[0033] 7. A textile product, including the bulky yarn according to
any one of the above items in at least part thereof.
[0034] The bulky yarn of the present invention is suppressed in
tanglement between the bulky yarns while having a loop shape, is
good in handleability in high-order processing, has a soft texture,
and is light and excellent in heat retention properties.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] FIG. 1 is a schematic side view of a bulky yarn according to
an example of the present invention.
[0036] FIG. 2 is a simulated view for illustrating a method for
measuring a center line of a textured yarn.
[0037] FIG. 3 is a simulated view for illustrating a
three-dimensional crimped structure.
[0038] FIG. 4 is a schematic process diagram schematically showing
an example of a method for producing a bulky yarn of the present
invention.
[0039] FIG. 5 is a schematic side view for illustrating a suction
nozzle used in the method for producing a bulky yarn of the present
invention.
[0040] FIG. 6 is a schematic cross-sectional view for illustrating
a discharge hole of a spinneret for a hollow cross section used in
the method for producing a bulky yarn of the present invention.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0041] Hereinafter, embodiments of the invention will be described.
Since the bulky yarn of the present invention can be obtained by
processing a multifilament, the bulky yarn and a material in the
course of production of the bulky yarn may be referred to as a
"textured yarn".
[0042] The bulky yarn of the present invention is made of synthetic
fibers and has a bulky structure. This structure is composed of a
sheath yarn forming loops and a core yarn that is twisted with the
sheath yarn to substantially fix the sheath yarn. A feature of the
structure is that the sheath yarn has a three-dimensional crimped
structure. In addition, in the present invention, the sheath yarn
is not substantially broken. That is, the sheath yarn is a bulky
yarn and is almost continuous. Moreover, the sheath yarn
continuously forms a plurality of loops.
[0043] Herein, the synthetic fibers are fibers made of a high
molecular weight polymer. The synthetic fibers used may be fibers
produced by melt spinning, solution spinning or the like. Among
high molecular weight polymers, a melt-moldable thermoplastic
polymer is suitable for use in the present invention because such
thermoplastic polymer can be used for producing the fibers used in
the present invention by a melt spinning method of high
productivity.
[0044] Herein, examples of the thermoplastic polymer include
melt-moldable polymers such as polyethylene terephthalate and
copolymers thereof, polyethylene naphthalate, polybutylene
terephthalate, polytrimethylene terephthalate, polypropylene,
polyolefins, polycarbonate, polyacrylate, polyamides, polylactic
acid, and thermoplastic polyurethane. Among these thermoplastic
polymers, polycondensation polymers typified by polyesters and
polyamides are suitable because these polymers are crystalline
polymers and have a high melting point, so that they are free from
deterioration or fatigue even if they are heated at a relatively
high temperature in the subsequent process, molding processing, and
actual use. From the viewpoint of heat resistance, the melting
point of the polymer is preferably 165.degree. C. or higher.
[0045] The synthetic fibers used in the present invention may
contain various additives such as inorganic substances including
titanium oxide, silica, and barium oxide, coloring agents such as
carbon black, dyes, and pigments, flame retardants, fluorescent
whitening agents, antioxidants, and ultraviolet absorbers.
[0046] As illustrated in FIG. 1, the bulky yarn according to
embodiments of the present invention is composed of a sheath yarn 1
forming loops and a core yarn 2 twisted with the sheath yarn to
substantially fix the sheath yarn.
[0047] See FIG. 2. The core yarn is a filament, and is preferably
present in the range of 0.6 mm from a center line 3 of a textured
yarn. The center line of a textured yarn means a straight line
connecting a pair of thread guides 4 on which a textured yarn of a
fixed length is threaded. A filament present within the range of a
distance 5 from the center line of the textured yarn of 0.6 mm or
less is the core yarn referred to herein, and serves as a
supporting yarn for the loops of the sheath yarn. The sheath yarn
is also a filament, and is preferably protruded in a loop shape at
a distance of 1.0 mm or more from the center line of the textured
yarn. The sheath yarn is responsible for the bulkiness of the yarn
of the present invention. In the present invention, the core yarn
fixes the sheath yarn forming loops. The twist points play a role
of supporting loops of the sheath yarn which are a feature of the
present invention, and are suitably present at a moderate period.
From this viewpoint, it is preferable that the core yarn and the
sheath yarn in the bulky yarn have 1/mm to 30/mm twist points per 1
mm of the bulky yarn. When the number of twist points is within
this range, even after the sheath yarn is three-dimensionally
crimped, the loops are present at a moderate interval. Further from
this viewpoint, it is more preferable that the number of twist
points be 5/mm to 15/mm.
[0048] In order to define the core yarn and the sheath yarn and
continuously evaluate the number of twist points and the number of
loops per unit length in the longitudinal direction of the bulky
yarn, a photoelectric fluff detection device can be utilized. For
example, with use of a photoelectric fluff measuring machine (TORAY
FRAY COUNTER), distances of 0.6 mm and 1.0 mm from the center line
of the textured yarn are evaluated under the conditions of a yarn
speed of 10 m/min and a traveling yarn tension of 0.1 cN/dtex.
[0049] The sheath yarn having loops according to embodiments of the
present invention has a protruding shape in the cross section of
the bulky yarn as viewed from the longitudinal direction of the
bulky yarn, and has larger loops than those of common interlaced
yarns and taslan textured yarns.
[0050] Herein, the size of each loop means the distance 5 from the
center line 3 of the textured yarn to the apex of the loop as shown
in FIG. 2. The size of the loop is measured by observing a bulky
yarn of a fixed length threaded on the pair of thread guides 4 from
the side surface, and measuring the size in the observed image. A
photograph of one randomly selected bulky yarn is taken so that 10
or more loops formed in the bulky yarn can be observed, and the
distance 5 from the center line of the textured yarn to the apex of
each loop is measured for 10 loops in the image. Total of 10 sites
per one bulky yarn are photographed, and the size of a total of 100
loops per one bulky yarn is measured up to the second decimal place
in millimeters. The average of these numerical values is
calculated, and a value obtained by rounding off the average to the
first decimal place is taken as the size of the loops in the bulky
yarn.
[0051] According to the study of the inventors, as for the size of
the loops, it is preferable that the distance of protrusion of the
loops from the center line of the textured yarn be in the range of
1.0 mm or more and 100.0 mm or less. When the distance is within
this range, in combination with the crimped structure of the sheath
yarn, the loops enhance the intended effects according to
embodiments of the present invention, that is, the bulkiness and
suppression of tanglement. In consideration of processability into
a bulky yarn described later, the distance is more preferably 3.0
mm or more and 70.0 mm or less. Moreover, in consideration of
repeated deformation with compression recovery under harsh
environments as in sports clothing, it is particularly preferable
to set the distance to 5.0 mm or more and 60.0 mm or less.
[0052] Herein, the shape of the loops of the sheath yarn is
preferably a teardrop-shaped loop (teardrop shape) rather than an
arched loop formed by general interlacing. In the case of the
arched loop, the twist point between the core yarn and the sheath
yarn is not fixed, and the loop moves freely to some extent.
Therefore, when compressive deformation is applied to such a yarn,
the twist point will move. For this reason, the yarn hardly returns
to the original shape after compressive deformation, so that the
yarn having an arched loop may be disadvantageous from the
viewpoint of durability of the bulkiness. On the other hand, in the
case of the teardrop-shaped loop, since the loop is substantially
fixed at the twist point with the core yarn, the loop of the sheath
yarn easily returns to the original shape even after compressive
deformation. Thus, this shape is suitable for exhibiting the
bulkiness originally having resilience. The teardrop-shaped loop,
however, has been thought to be disadvantageous from the viewpoint
of suppressing the tanglement between the sheath yarns since the
sheath yarns are fixed. In embodiments of the present invention,
the three-dimensionally crimped sheath yarns suppress the
tanglement between the sheath yarns. Further, the present inventors
also found that the three-dimensional crimp and the loop shape can
develop high bulkiness.
[0053] It was found that the above-mentioned effects tend to
deteriorate when the loops of the sheath yarns are broken in the
middle or partially deteriorated. For this reason, in embodiments
of the present invention, the sheath yarns are not substantially
broken in order to satisfy the contradicting characteristics of
both the bulkiness and suppression of tanglement unprecedentedly.
It is particularly preferable that the sheath yarn be not
substantially broken in the middle of the loop.
[0054] In the determination of loop breakage in the present
invention, at 10 sites randomly selected from a single textured
yarn consisting of a sheath yarn and a core yarn, the textured yarn
is photographed at a magnification at which 10 or more sections
from a twist point between the core yarn and the sheath yarn to the
next twist point (that is, each section is one loop) can be
recognized in the longitudinal direction of the textured yarn, and
observed for the determination. That is, for each of the 10
photographed images, the number of breaking points of the sheath
yarn per 1 mm of the bulky yarn was counted for 10 loops. The
average of the number of breaking points of the loops was
calculated, and the average was rounded off to the first decimal
place to give the number of breaking points of the loops
(number/mm). Herein, when the number of breaking points on average
of the total of 100 loops is 0.2/mm or less, it means that the
sheath yarn according to the present invention is not substantially
broken, that is, the sheath yarn is almost continuous in the length
direction of the bulky yarn. When the number of breaking points is
within this range, there is substantially no sheath yarn that has a
free end, and it is possible to form loops that are not tangled
with other sheath yarns.
[0055] In the case of subjecting a yarn to real twisting and then
an untwisting step, or intermingling and opening the yarn in the
nozzle by strong air injection as in the conventional method, the
traveling thread may be slammed into the inside of the nozzle made
of metal at high frequency to be broken or deteriorated. Further,
when loops are to be formed, it is necessary to scratch the yarn
between rubber discs to untwist the yarn, so that the sheath yarn
may be broken or the mechanical properties may be largely
deteriorated. Accordingly, it is thought that the broken sheath
yarn is wound around other sheath yarns or the sheath yarns are
tangled with each other to promote the entanglement, resulting in
constraining the structural form and high-order processing of the
yarn. In the present invention, these points are greatly remedied,
and as described above, the effects produced by the
three-dimensionally crimped sheath yarn can be sufficiently
exhibited.
[0056] The sheath yarn responsible for the bulkiness has a
three-dimensional crimped structure, and is not substantially
broken and continuously forms loops. The three-dimensional crimped
structure in the present invention means a structure in which a
filament single yarn has a spiral structure as illustrated in FIG.
3.
[0057] For the evaluation of the three-dimensional crimp, at each
of 10 sites randomly selected from a bulky yarn, 10 or more sheath
yarns are selected, and the sheath yarns are observed with a
digital microscope or the like at a magnification at which the
crimp form of the sheath yarns can be recognized. In these images,
if the observed sheath yarns have a spirally swirling form, the
sheath yarns are determined to have a three-dimensional crimped
structure, and if not, the sheath yarns are determined not to have
a three-dimensional crimped structure.
[0058] Fibers having such a three-dimensional crimped structure
similar to a spring have resilience against elongation deformation
and compressive deformation. The bulky yarn of the present
invention exhibits comfortable resilience since the sheath yarn has
such structure. In the case where the bulky yarn of the present
invention is doubled and filled in the form of a yarn bundle
between fabrics, the peculiar resilience produced by the bulky yarn
of the present invention develops a good touch of the filled
material, and the sheath yarn supporting the filled material
recovers the shape like a spring even after repeated compression
recovery. Thus, the bulky yarn is suitable also from the viewpoint
of suppression of fatigue. The size of the three-dimensional crimp
of a latent crimped yarn which is obtained by common production
methods, such as conventional side-by-side composite fibers and
hollow fibers, is generally on the order of microns (10.sup.-6 m).
In the present invention, in order to enhance the effects of the
present invention, it is preferable that the size of the crimp be
on the order of millimeters (10.sup.-3 m) which is larger than the
above. In the present invention, owing to such size of the
three-dimensional crimp, it is possible to freely control the
bulkiness at the cross section of the bulky yarn viewed from the
longitudinal direction of the bulky yarn as well as the resilience
of the bulky yarn. With use of the resilience, it is naturally
possible to suppress the tanglement between the sheath yarns, which
is one of the objects of the present invention. In particular, when
the crimp size is set to a value on the order of millimeters,
tanglement between the sheath yarns is suppressed while both the
bulkiness and compressibility of mainly the sheath yarn are
satisfied.
[0059] In the sheath yarn of the present invention, the spirally
swirling spiral structure preferably has a radius of curvature in
the range of 1.0 to 30.0 mm. Herein, for the determination of the
radius of curvature of the spiral structure, an image
two-dimensionally observed with a digital microscope or the like is
used in the same manner as in the above-mentioned determination of
the presence or absence of the three-dimensional crimp. As shown in
FIG. 3, the radius of a curvature 6 formed by a fiber having a
spiral structure is defined as the radius of curvature. At each of
10 sites randomly selected from a bulky yarn, 10 or more sheath
yarns are collected, and the sheath yarns are observed with a
digital microscope or the like at a magnification at which the
crimp form of the sheath yarns can be recognized. In this way, the
radius of curvature of a total of 100 sheath yarns is measured up
to the second decimal place in millimeters. The simple average of
these measured values is calculated, and a value obtained by
rounding off the average to the first decimal place is taken as the
radius of curvature of the three-dimensional crimped structure.
[0060] The radius of curvature is more preferably 2.0 to 20.0 mm.
When the radius of curvature is within this range, the sheath yarns
come into point contact with each other while having moderate
resilience against the compression of the bulky yarn in the cross
section viewed from the longitudinal direction of the bulky yarn,
so that the bulkiness having moderate resilience is exhibited. The
radius of curvature is particularly preferably 3.0 to 15.0 mm. When
the radius of curvature is within this range, there is no problem
in the long-term durability of the bulky yarn, and the effects of
the present invention are positively exerted when the bulky yarn is
used in clothing applications in which compression recovery is
repeatedly exerted, particularly sports clothing used under harsh
environments. This is because the single yarn itself has a
three-dimensional stereoscopic form rather than two-dimensional
bending that can be imparted by mechanical pushing, and has a
spiral structure or a similar structure. Since these crimps have a
form of fine crimps on the order of microns, the fine spiral
structures mesh with each other, so that the entanglement is easily
promoted.
[0061] Meanwhile, the present inventors pushed forward the study
focusing on the form of the monofilaments, in order to achieve
suppression of tanglement between the bulky yarns which is one of
the objects of the present invention. As a result, they found that
a phenomenon completely opposite to the conventional recognition
occurs when the sheath yarn is formed of a single yarn having a
three-dimensional crimp on the order of millimeters. This is
thought to be because the bulky yarns have a suitable excluded
volume even when being made into a yarn bundle since the sheath
yarns have a three-dimensional crimp on the order of millimeters,
and the meshing between the sheath yarns is largely suppressed.
That is, the sheath yarn in the bulky yarn of the present invention
has a movable space depending on the size of the loops. According
to the definition of the present invention, each loop has, around
the twist point thereof, a relatively large hemispherical movable
space having a radius of 1.0 mm or more. In this case, the sheath
yarns having a three-dimensional crimp which is overwhelmingly
large in size relative to the fiber diameter come into point
contact with each other and resile each other, so that each sheath
yarn can exist alone without being tangled with other sheath yarns.
Further, in the sheath yarn having a three-dimensional crimp, in
addition to having the movable space described above, the sheath
yarn itself can elongate like a spring in the fiber axis direction.
Thus, when the sheath yarns cross each other, the sheath yarns can
be easily unwound by the application of vibration.
[0062] Furthermore, the three-dimensional crimp of the sheath yarn
works effectively also from the viewpoint of bulkiness which is the
basic characteristics of the present invention. The point contact
between the sheath yarns as described above produces an effect that
the sheath yarns resile one another even within one bulky yarn, and
not only the initial bulkiness but also the state where the loops
of the sheath yarns are radially opened can be maintained even
after the lapse of time. The spring-like behavior of the sheath
yarn of the present invention is difficult to achieve with a
conventional merely straight sheath yarn.
[0063] The feature of form that the sheath yarn of the present
invention forms loops and has a three-dimensional crimped structure
also has an effect on the reduction of the coefficient of friction.
As described above, this is the effect produced by the point
contact of the sheath yarn with other sheath yarns, and is one of
the effects produced by the bulky yarn having the unique structure
of the present invention. According to the study of the present
inventors, it is preferable that the coefficient of static friction
between fibers be 0.3 or less in order to suppress tanglement
between the bulky yarns while maintaining the bulkiness. The
"coefficient of static friction between fibers" as used herein is
measured with a radar type coefficient of friction tester according
to the method described in "coefficient of friction" in JIS L 1015
(2010) "Chemical fiber staple testing method". Since the JIS is
intended for staples, the standard specifies that a preliminary
work such as opening of fibers should be carried out for the
measurement. In the measurement according to the present invention,
however, treatment such as opening of fibers is not carried out,
and the coefficient of friction can be evaluated by arranging bulky
yarns in parallel into a cylindrical sliver.
[0064] In the case where the bulky yarn of the present invention is
made into a textile product, the coefficient of static friction
between fibers is preferably low since the texture is improved if
the fibers moderately slide and move at the time of compression.
The coefficient of static friction between fibers is more
preferably 0.2 or less, particularly preferably 0.1 or less.
[0065] In addition, from the viewpoint of seeking for a more
excellent touch with the bulky yarn of the present invention, the
sheath yarn and the core yarn preferably have a single yarn
fineness ratio (sheath/core) in the range of 0.5 to 2.0. When the
single yarn fineness ratio is within this range, the fineness of
the sheath yarn is close to that of the core yarn, and the bulky
yarn can be used without any feeling of a foreign body when
compressed. Further, a range of the single yarn fineness ratio
(sheath/core) in which the bulky processing can be efficiently
carried out may be 0.7 to 1.5. Further, in the bulky yarn of the
present invention, it is possible to combine various fibers. From
the viewpoint of the efficient fluid processing and no feeling of a
foreign body at the time of compression as described above, the
core yarn and the sheath yarn suitably have the same single yarn
fineness and the same mechanical properties. Specifically, in the
present invention, it is preferable to prepare two or more fibers
produced under the same yarn-making conditions and use them in the
core yarn and the sheath yarn. In particular, it is preferable that
these fibers be made from one kind of (single) resin.
[0066] From the viewpoint of reduction of the coefficient of
friction and suppression of tanglement in the bulky yarn as
described above, it is preferable that the core yarn also have a
three-dimensional crimped structure on the order of millimeters in
addition to the sheath yarn. The radius of curvature of the spiral
structure of the core yarn is preferably in the range of 1.0 to
30.0 mm. When the radius of curvature is within this range, at the
twist point of the core yarn substantially fixing the sheath yarn,
there is an inter-filament void derived from the three-dimensional
crimp of the core yarn. In this case, when no tension is applied to
the bulky yarn, the fulcrum of the loop can move in a limited space
also in the longitudinal direction. Thus, the movable space of the
sheath yarn is expanded, and the effects of the present invention,
that is, the suppression of tanglement and a soft texture, are more
remarkably exhibited. On the other hand, when tension is applied to
the bulky yarn, the core yarn elongates and the binding force at
the twist point between the core yarn and the sheath yarn is
increased, so that practically positive effects such as prevention
of loosening of the loops and falling off of the sheath yarn can be
exhibited. The three-dimensional crimp of the core yarn can also be
confirmed by observing a randomly collected core yarn in accordance
with the evaluation method for the three-dimensional crimp of the
sheath yarn as described above. The radius of curvature of the
spiral structure of the core yarn is more preferably 3.0 to 15.0
mm. When the radius of curvature is within this range, the bulky
yarn is good in the long-term durability, and the effects of the
present invention are positively exerted when the bulky yarn is
used in clothing applications or sports clothing in which
elongation deformation is repeatedly applied to the bulky yarn.
[0067] It is preferable that the core yarn and/or the sheath yarn
used in the present invention be hollow section fibers. It is more
preferable that the fibers having a three-dimensional crimped
structure be hollow section fibers. This is because the hollow
section fibers are advantageous in that the size of the
three-dimensional crimp can be adjusted relatively freely from
large to small.
[0068] Also from the viewpoint of protrusion of the loops, the
hollow section fibers are preferable. The reason will be described
below. In the bulky yarn according to embodiments of the present
invention, the loops of the sheath yarn originate from the twist
points with the core yarn, and are capable of protruding due to the
rigidity of the sheath yarn. In view of prevention of fatigue, it
is preferable that the sheath yarn itself have a small mass.
Therefore, from the viewpoint of the lightweight properties of the
sheath yarn, hollow section fibers having a hollow rate of 20% or
more are preferable. Herein, the "hollow rate" is the volume
fraction of a part of the fibers in which no material is
present.
[0069] For example, the hollow rate can be measured by the
following method. The sheath yarn or the core yarn is cut so that
the cross section can be observed, and then the cross section of
the fibers is photographed with an electron microscope (SEM) at a
magnification at which cross sections of 10 or more fibers can be
observed. From the photographed image, 10 fibers are randomly
selected and extracted, and the equivalent circle diameters of the
fibers and the hollow portions are measured with image processing
software. The area rate of the hollow portions is calculated from
the measured values. The above-mentioned operation is carried out
on the 10 photographed images, and the average of the 10 images is
taken as the hollow rate of the hollow section fibers of the
present invention.
[0070] In the case of round hollow fibers, there are the following
methods for conveniently evaluating the hollow rate.
[0071] The side surface of a hollow section fiber is observed with
an enlarging means such as a microscope, and the fiber diameter in
terms of the round cross section is obtained from the image. From
the fiber diameter and the density of the fiber material, the rate
of the measured fineness to the fineness of a non-hollow fiber can
be calculated as the hollow rate.
[0072] From the viewpoint of lightweight and heat retention
properties which are objects of the present invention, the bulky
yarn of the present invention suitably contains more air. Thus, the
hollow rate is more preferably 30% or more. When the hollow rate is
within this range, it is possible to feel better lightweight
properties when a bundle of the bulky yarns is held. In addition,
since a bulky yarn having such a hollow rate contains more air
having a low thermal conductivity inside, it is possible to further
enhance the heat retention properties. From such a viewpoint, the
higher the value of the hollow rate is, the more suitable it is.
The hollow rate, however, is preferably 50% or less in order that
the hollow portions may be stably produced without being collapsed
in the yarn-making step and the fluid processing step described
later.
[0073] The bulky yarn of the present invention has excellent
bulkiness, and it is preferable that the yarn that constitutes the
bulky yarn have moderate resilience. In consideration of the
problems to be solved by the present invention, it is preferable
that the synthetic fibers that constitute the bulky yarn have a
single yarn fineness of 3.0 dtex or more. Further, it is preferable
that the filaments that constitute the bulky yarn have moderate
rigidity, since deformation such as repeated compression recovery
is applied to the bulky yarn when the bulky yarn is used as
batting. Thus, it is more preferable that the single yarn fineness
be 6.0 dtex or more. Herein, the fineness means a value calculated
from the obtained fiber diameter, number of filaments, and density,
or a value of the mass per 10000 m calculated from the simple
average of a plurality of measurements of the weight of the fibers
per unit length.
[0074] The bulky yarn of the present invention preferably has a
breaking strength of 0.5 to 10.0 cN/dtex and an elongation of 5% to
700%. Herein, the strength is a value obtained by drawing a
load-elongation curve of a yarn under the conditions shown in JIS L
1013 (1999), and dividing the load value at break by the initial
fineness. The elongation is a value obtained by dividing the
elongated length at break by the initial sample length. The
breaking strength of the bulky yarn of the present invention is
preferably 0.5 cN/dtex or more in order for the bulky yarn to have
process passability in the high-order processing step and to be
capable of withstanding practical use, and the practicable upper
limit of the breaking strength is 10.0 cN/dtex. In addition, it is
preferable that the elongation be 5% or more in consideration of
process passability in the post-processing step, and the
practicable upper limit of the elongation is 700%. The breaking
strength and elongation can be adjusted by controlling the
conditions in the production process depending on the intended use.
In the case where the bulky yarn of the present invention is used
in general clothing applications such as inner and outer clothing,
or bedclothes such as futons and pillows, the breaking strength is
preferably 0.5 to 4.0 cN/dtex. Further, in sports clothing
applications in which the usage conditions are relatively harsh,
the breaking strength is preferably 1.0 to 6.0 cN/dtex.
[0075] The bulky yarn of the present invention can be made into
various fiber structures such as fiber winding packages, tows, cut
fibers, batting, fiber balls, cords, pile, and woven, knitted, and
nonwoven fabrics, and further made into various textile products.
Herein, the "textile products" can be used in applications such as
general clothing, sports clothing, clothing materials, interior
products such as carpets, sofas, and curtains, vehicle interior
products such as car seats, daily necessaries such as cosmetics,
cosmetic masks, wiping cloths, and health supplies, and
environmental and industrial materials such as filters and products
for removing hazardous substances. In particular, the bulky yarn of
the present invention is suitably used as the batting because of
its bulkiness and effects such as suppression of tanglement. In
this case, since the batting is filled into the outer fabric, the
bulky yarn is preferably made into a yarn bundle of several to
several tens of yarns, or a sheet-like material such as a nonwoven
fabric. In particular, as for the bulky yarn made into a sheet, it
is easy to fill the sheet into an outer fabric, and to adjust the
filling amount depending on the intended use. For this reason, the
bulky yarn is made into a thin, light material having heat
retention properties, and there is no concern that the material
comes out of an outer fabric. Since unnecessary sewing can be
omitted, there is no restriction on the form of the textile
product, and the textile product may have a complicated design.
[0076] Hereinafter, an example of the method for producing a bulky
yarn of the present invention will be described.
[0077] As the core yarn and the sheath yarn used in the present
invention, synthetic fibers obtained by fiberizing a thermoplastic
polymer by a melt spinning method may be used.
[0078] The spinning temperature for obtaining the synthetic fibers
used in the present invention is a temperature at which the used
polymer exhibits fluidity. The temperature at which the polymer
exhibits fluidity varies depending on the molecular weight. An
indication of the temperature is the melting point of the polymer,
and the temperature may be set at a temperature equal to or higher
than the melting point to (melting point+60.degree. C.) or lower. A
temperature of (melting point+60.degree. C.) or lower is preferable
because the polymer is not thermally decomposed in a spinning head
or a spinning pack, and the reduction in the molecular weight is
suppressed. In addition, the discharge amount of the polymer is
generally 0.1 g/min/hole to 20.0 g/min/hole per discharge hole
since a discharge amount within this range allows stable discharge
of the polymer. In this case, it is preferable to consider the
pressure loss in the discharge hole at which the stable discharge
can be ensured. A preferable indication of the pressure loss is
within the range of 0.1 MPa to 40 MPa, and the pressure loss can be
adjusted according to the melt viscosity of the used polymer, the
specification of the discharge hole, and the discharge amount.
[0079] The molten polymer discharged in this manner is cooled and
solidified, an oil agent is imparted to the molten polymer, and the
molten polymer is taken up with a roller to be formed into fibers.
Herein, the take-up speed should be determined according to the
discharge amount and the intended fiber diameter. In order to
stably produce the fibers, it is preferable to set the take-up
speed in the range of 100 to 7000 m/min. From the viewpoint of
enhancing the orientation of the synthetic fibers and improving the
mechanical properties thereof, the synthetic fibers may be wound up
and then stretched, or the synthetic fibers may be stretched
without being wound up once. As for the stretching conditions, for
example, in a stretching machine having one or more pairs of
rollers, in the case of a melt-spinnable polymer, generally, the
polymer is stretched by the circumferential speed ratio between a
first roller set at a temperature equal to or higher than the glass
transition temperature and a second roller set at about a
crystallization temperature (second roller/first roller), and then
the polymer is wound up on a winding machine. In the case of a
polymer that exhibits no glass transition, a dynamic
viscoelasticity measurement (tan .delta.) of the composite fibers
may be carried out, and a temperature equal to or higher than the
peak of the temperature/tan .delta. curve (when there are a
plurality of peaks, the one having the highest temperature) as a
preliminary heating temperature may be employed as the first roller
temperature. Herein, from the viewpoint of increasing the stretch
ratio and improving the mechanical properties, it is also a
suitable means to carry out the stretching step in multiple
stages.
[0080] The cross-sectional shape of the synthetic fibers of the
present invention is not particularly limited, and fibers having a
general round cross section, a triangular cross section, a Y-shaped
cross section, an octofoil cross section, a flat cross section, or
an amorphous shape such as a polymorphic cross section or a hollow
cross section can be obtained by changing the shape of the
discharge hole of the spinneret. Further, there is no need to form
the synthetic fibers from a single polymer, and the fibers may be
composite fibers formed from two or more kinds of polymers.
However, from the viewpoint of developing the three-dimensional
crimp of the sheath yarn, which is an important requirement of the
present invention, it is appropriate to use side-by-side composite
fibers having a hollow cross section and including two kinds of
polymers bonded together. In these fibers, a three-dimensional
crimp can be developed due to the presence of foreign substances in
the cross section of the monofilaments by subjecting the fibers to
yarn-making and yarn processing, and the subsequent heat treatment.
Therefore, although the fibers are so-called straight fibers at the
time of fluid processing described later, the fibers develop the
three-dimensional crimp through the loop forming step of the sheath
yarn and the subsequent heat treatment.
[0081] If the fibers are straight at the time of bulky processing,
the threads are easy to stably travel without blocking a nozzle or
the like. Also in forming the loops of the present invention, the
core yarn and the sheath yarn are efficiently swirled, so that the
loops have very similar shapes in the fiber axis direction of the
textured yarn. Heat-treating the textured yarn having the loops at
around the crystallization temperature of the polymer makes the
sheath yarn develop a three-dimensional crimp to give a bulky yarn.
The three-dimensional crimp of the sheath yarn develops
satisfactory bulkiness both in the circumferential direction and in
the cross-sectional direction of the textured yarn. It is
preferable to control the three-dimensional crimp to a moderate
level depending on the desired characteristics.
[0082] From the viewpoint of controlling the degree of crimp
development after the heat treatment, it is more preferable that
the fibers used be hollow section fibers made from a monocomponent
polymer. Hollow section fibers have an air layer having low thermal
conductivity at the center of the fibers. Therefore, a difference
in the structure is produced in the cross-sectional direction of
the fibers, for example, by discharging the fibers from a spinneret
capable of forming a hollow cross section, and then forcibly
cooling one side of the fibers with excessive cooling air or the
like, or excessively heat-treating one side of the fibers with a
heating roller or the like at the time of stretching. In the case
of hollow section fibers made from a monocomponent polymer, not
only the fibers are capable of yarn-making with a single spinning
machine, but also a three-dimensional crimp in a large size to a
small size can be relatively easily obtained by the above-mentioned
operation. Therefore, such fibers are suitable for use in the
present invention. Also from the viewpoint of crimp control by the
above-mentioned operation, as described above, the hollow rate is
preferably 20% or more, more preferably 30% or more.
[0083] Next, an example of a method for producing a bulky yarn from
fibers obtained by spinning will be described.
[0084] The method for producing a bulky yarn described herein as an
example is roughly composed of two steps. The first step is bulky
processing in which a core yarn and a sheath yarn are twisted with
each other with a fluid to form loops of the sheath yarn. The
second step is a heat treatment step in which the thread having
been subjected to the bulky processing is subjected to heat
treatment to make the sheath yarn develop a three-dimensional
crimp.
[0085] An example of the method for producing a bulky yarn of the
present invention will be described with reference to the schematic
process diagram in FIG. 4. In the first step, a predetermined
amount of synthetic fibers 8 as a raw material are unwound with
supply rollers 7 having a nip roller or the like, and sucked as a
core yarn and a sheath yarn with a suction nozzle 9 capable of
injecting compressed air.
[0086] In the suction nozzle 9, the flow rate of the compressed air
injected from the nozzle should be such a flow rate that the thread
inserted from the supply rollers into the nozzle has the minimum
required tension and stably travels between the supply rollers and
the nozzle and within the nozzle without swaying. Although the
optimum flow rate varies depending on the hole diameter of the used
suction nozzle, an indicator of the range in which the tension can
be imparted to the yarn and the loops described later can be
smoothly formed is an air speed in the nozzle of 100 m/s or more.
An indicator of the upper limit of the air speed is 700 m/s or
less. When the air speed is within this range, the thread can
stably travel inside the nozzle without being swayed by the
excessively injected compressed air.
[0087] In addition, from the viewpoint of preventing intermingling
and opening of the textured yarn inside the suction nozzle, a
propellant air jet stream injected at an injection angle (reference
sign 16 in FIG. 5) of the compressed air less than 60.degree. with
respect to the traveling thread is preferable. This is because the
loops of the sheath yarn can be uniformly formed with high
productivity. Processing with a vertical air jet stream of a fluid
injected at an injection angle of 90.degree. with respect to the
traveling thread is of course capable of producing the bulky yarn
of the present invention. However, processing with a propellant air
jet stream is preferable from the viewpoint of suppressing the
opening of the traveling thread due to the injection of the air jet
stream from the vertical direction, and suppressing the tanglement
between single yarns in a narrow space in the nozzle. The
processing with the propellant air jet stream can also suppress the
formation of arch-shaped small loops in a short period, which are
easily formed in the case of the vertical air jet stream.
[0088] In order to form the loops of the sheath yarn required for
the bulky yarn of the present invention, it is suitable not to
carry out intermingling or opening in the suction nozzle. From the
viewpoint of making a multifilament composed of single-digit number
to double-digit numbers of yarns travel in the nozzle without being
opened, it is more preferable that the injection angle of the
compressed air be 45.degree. or less with respect to the traveling
thread. Furthermore, in order to form loops outside the nozzle as
described later, it is suitable that the injected air stream
immediately after the nozzle have high stability and high
propelling power. From this viewpoint, the injection angle is
particularly preferably 20.degree. or less with respect to the
traveling thread.
[0089] There are cases where the threads led to the suction nozzle
are fed at once or in two installments. In order to produce the
bulky yarn of the present invention, it is suitable to process the
yarn by feeding the threads in two installments. The wording
"feeding in two installments" as used herein refers to a technique
of supplying the core yarn and the sheath yarn to the nozzle at
different feed speeds (amounts) with separate supply rollers or the
like. The turning force caused by an air stream described later is
utilized, so that one of the yarns that is excessively supplied
serves as a sheath yarn and forms loops.
[0090] When the feeding in two installments is carried out, it is
also possible to form loops in the nozzle with use of an
interlacing nozzle or a taslan nozzle that imparts the effects of
intermingling, opening, and interlacing to the traveling thread
inside the nozzle. However, the textured yarn obtained with such a
nozzle tends to have loops formed in a short period, and also tends
to have loops small in size.
[0091] Therefore, in order to produce a bulky yarn satisfying the
objects of the present invention, it is necessary to precisely
control a large number of parameters. In addition, when
multi-spindle spinning is carried out, there is a possibility that
the bulkiness of the bulky yarn will be different by the spindle.
Thus, it is suitable to employ a technique based on air stream
control outside the nozzle as described later also from the
viewpoint of stability of the quality. As for this point, the
present inventors considered not to positively carry out
intermingling and opening in the nozzle.
[0092] Next, a step of swirling, outside the nozzle, the thread to
which the compressed air has been applied to form loops of the
sheath yarn is carried out. This operation is based on a concept
that loops can be formed by swirling the supplied two yarns at a
position distant from the nozzle. It was found that there is a
specific phenomenon in which the sheath yarn swirls while being
opened outside the nozzle when the ratio of the air speed to the
yarn speed (air speed/yarn speed) is 100 to 3000.
[0093] Herein, the air speed means the speed of the air stream
injected together with the traveling thread from the suction nozzle
outlet. This speed can be controlled by the discharge diameter of
the nozzle and the flow rate of the compressed air. Further, the
yarn speed can be controlled by the circulating speed of the
rollers which take up the yarn after the fluid processing nozzle.
Since the turning force of the traveling thread increases and
decreases depending on the speed ratio between the air stream and
the yarn, in the case of strengthening the twist point of the
intended bulky yarn, this speed ratio should be approximated to
3000. Alternatively, in the case of loosening the twist point, this
speed ratio should be approximated to 100. Varying this speed
ratio, for example, by intermittently varying the flow rate of the
compressed air, or by varying the speed of the take-up rollers, can
vary the degree of the twist point. Meanwhile, in the case where
the bulky yarn of the present invention is used in applications in
which deformation of compression recovery is repeatedly applied as
in the batting, it is preferable to set the air speed/yarn speed to
200 to 2000. In particular, in the case of producing a bulky yarn
used in clothing such as jackets to which deformation is frequently
applied, it is particularly preferable to set the air speed/yarn
speed to 400 to 1500 from the viewpoint of imparting moderate
binding and flexibility.
[0094] The turning force is developed when the accompanying air
stream gets away from the traveling thread. Then, a turning point
10 for changing the thread path is arranged. Specifically, the
thread path may be changed with a bar guide or the like. Then, the
thread is taken up at a predetermined speed, so that the sheath
yarn is swirled around the core yarn to form loops. From the
viewpoint of ensuring the space for the swirling and of loosening
the sheath yarn by the vibration utilizing the diffusion of the air
stream injected from the nozzle, it is suitable that the turning
point of the traveling thread be located away from the nozzle
discharge hole. However, the distance between the nozzle and the
turning point which is suitable for producing the bulky yarn of the
present invention varies depending on the speed of the ejected air
stream. The turning point 10 is preferably present within a range
in which the ejected air stream travels for 1.0.times.10.sup.-5 to
1.0.times.10.sup.-3 seconds. In order to form twist points between
the core yarn and the sheath yarn at an appropriate period in
balance with the diffusion of the air stream, the distance between
the nozzle and the turning point is more preferably present within
a range in which the ejected air stream travels for
2.0.times.10.sup.-3 to 5.0.times.10.sup.-4 seconds.
[0095] Adjusting the position of the turning point enables control
of the period of the twist points of the bulky yarn of the present
invention. The twist points play a role of supporting the
self-supporting loops of the sheath yarn which are a feature
according to embodiments of the present invention, and are suitably
present at a moderate period. From this viewpoint, it is preferable
to adjust the turning point so that the core yarn and the sheath
yarn in the bulky yarn have 1/mm to 30/mm twist points. When the
number of twist points is within this range, it is preferable
because even after the sheath yarn is three-dimensionally crimped,
the loops are present at a moderate interval. Further from this
viewpoint, it is more preferable to adjust the turning point so
that the number of twist points be 5/mm to 15/mm.
[0096] A textured yarn 11 (FIG. 4) having loops of the sheath yarn
is preferably subjected to heat treatment after being wound up once
or following the bulky processing for the purpose of fixing the
form and developing the three-dimensional crimp. FIG. 4 illustrates
a processing step of carrying out heat treatment subsequently to
the loop forming step.
[0097] The heat treatment is carried out, for example, with a
heater 13 (FIG. 4). An indicator of the temperature is the
crystallization temperature of the used polymer .+-.30.degree. C.
When the heat treatment is carried out at a temperature within this
range, there is no fused and cured portion between the sheath yarns
and between the core yarns, and no feeling of a foreign body, and
the good touch is not impaired, since the treatment temperature is
far from the melting point of the polymer. The heater used in the
heat treatment step may be a general contact heater or non-contact
heater. From the viewpoint of bulkiness before the heat treatment
and suppression of deterioration of the sheath yarn, use of a
non-contact heater is preferable. The non-contact heater herein may
be an air heating heater such as a slit heater or a tube heater, a
steam heater for heating with high temperature steam, or a halogen
heater, a carbon heater, or a microwave heater based on radiation
heating.
[0098] Herein, from the viewpoint of heating efficiency, a heater
based on radiation heating is preferable. As for the heating time,
for example, the time for fixing the fiber structure of the fibers
that constitute the textured yarn, fixing the form of the textured
yarn, and completing the crimp development of the sheath yarn
through the crystallization should be taken into consideration.
Thus, the treatment temperature and time should be adjusted
according to the desired characteristics. After completion of the
heat treatment step, the speed of the textured yarn may be
restricted with a roller 14 (FIG. 4), and the textured yarn may be
wound on a winder 15 having a tension control function. The wound
shape is not particularly limited, and it is possible to employ the
so-called cheese winding or bobbin winding. In consideration of
processing into the final product, it is also possible to
preliminarily double a plurality of textured yarns to make a tow,
or form a sheet of the textured yarns as it is.
[0099] It is preferable to make a silicone oil agent uniformly
adhere to the bulky yarn of the present invention before and after
the heat treatment step. Preferably, a silicone film is formed on
the sheath yarn and the core yarn by moderately crosslinking the
silicone through heat treatment or the like. Herein, examples of
the silicone oil agent include dimethylpolysiloxane, hydrogen
methylpolysiloxane, aminopolysiloxane, and epoxypolysiloxane, and
these can be used alone or as a mixture. In order to form a uniform
film on the surface of the bulky yarn, the oil agent may contain a
dispersant, a viscosity modifier, a crosslinking accelerator, an
antioxidant, a flame retardant, and an antistatic agent as long as
the object of the adhesion of silicone is not impaired. The
silicone oil agent can be used without solvent or in the form of a
solution or an aqueous emulsion. From the viewpoint of uniform
adhesion of the oil agent, an aqueous emulsion is preferably used.
It is suitable that the silicone oil agent be treated so that 0.1
to 5.0% by mass of the silicone oil agent can be made to adhere to
the bulky yarn with use of an oil agent guide, an oiling roller, or
a spray. After that, it is preferable to dry the oil agent at an
arbitrary temperature for an arbitrary time to cause a crosslinking
reaction. The silicone oil agent can be made to adhere in plural
installments, and it is also suitable to laminate a strong silicone
film by making one kind of silicone or different kinds of silicone
adhere in plural installments. Forming a silicone film on the bulky
yarn by the above-mentioned treatment improves the slidability and
touch of the bulky yarn, and further enhances the effects of the
present invention.
EXAMPLES
[0100] Hereinafter, the bulky yarn of the present invention and the
effects thereof will be specifically described with reference to
examples.
[0101] In the examples and comparative examples, the following
evaluations were made.
[0102] A. Fineness
[0103] The mass of 100 m of fibers was measured and multiplied by
100 to calculate the fineness. This operation was repeated 10
times, and the simple average of the 10 values was obtained. The
simple average was rounded off to the first decimal place, and the
obtained value was taken as the fineness (dtex) of the fibers. The
single yarn fineness was calculated by dividing the fineness by the
number of filaments that constitute the fibers. Also for the single
yarn fineness, the value was rounded off to the first decimal
place, and the obtained value was taken as the single yarn
fineness.
[0104] B. Mechanical Properties of Fibers
[0105] Using a tensile tester "TENSILON" (registered trademark)
UCT-100 manufactured by ORIENTEC CORPORATION, fibers having a
sample length of 20 cm were pulled under the condition of a tension
speed of 100%/min, and a stress-strain curve was obtained. The load
at break was read, and the load was divided by the initial fineness
to calculate the breaking strength (cN/dtex). Further, the strain
at break was read, and the strain was divided by the sample length.
This value was multiplied by 100 to calculate the elongation at
break (%). Both for the breaking strength and elongation at break,
this operation was repeated 5 times at each level, the simple
average of the resultant values was obtained, and the obtained
value was rounded off to the first decimal place.
[0106] C. Evaluation of Loops (Size, Twist Point, and Breaking
Point)
[0107] A load of 0.01 cN/dtex was applied to a sample yarn so that
the sample yarn would not be slackened, and the yarn of a fixed
length was threaded on the pair of thread guides 4 as illustrated
in FIG. 2. The side surface of the threaded bulky yarn was
photographed with Microscope VHX-2000 manufactured by KEYENCE
CORPORATION at a magnification at which 10 or more loops could be
observed. For the 10 loops randomly selected from the image, a
distance 5 from a center line 3 of the textured yarn to the apex of
the loop at the tip of the loop (FIG. 2) was measured with image
processing software (WINROOF). Total of 10 sites per one textured
yarn were photographed, and the size of a total of 100 loops per
one textured yarn was measured up to the second decimal place in
millimeters. The average of these numerical values was calculated,
and a value obtained by rounding off the average to the first
decimal place was taken as the size of the loops in the bulky
yarn.
[0108] In the 10 images same as described above, a point at which a
sheath yarn having a loop apex at a position of 1.0 mm or more from
the center line 3 of the textured yarn crosses a straight line at a
position of 0.6 mm from the centerline 3 of the textured yarn was
defined as a twist point, and the number of twist points per 1 mm
of the textured yarn was counted. The number of twist points
(number/mm) of a total of 10 images was counted, and the average
thereof was rounded off to the closest whole number.
[0109] In the 10 images same as described above, the number of
breaking points in 10 loops per 1 mm of the textured yarn was
counted. The number of breaking points (number/mm) of a total of
100 loops per one bulky yarn was counted, and the average thereof
was rounded off to the first decimal place. Herein, a sample having
less than 0.2/mm breaking points was evaluated as a sample in which
the sheath yarn is not substantially broken (described as "absent"
in the description of the examples and comparative examples and in
Tables 1, 2, and 3), and a sample having 0.2/mm or more breaking
points was evaluated as a sample in which the sheath yarn is broken
(described as "present" in the description of the examples and
comparative examples and in the tables).
[0110] D. Evaluation of Crimp Form (Presence or Absence of
Three-Dimensional Crimp, and Radius of Curvature)
[0111] A textured yarn was observed at randomly selected 10 sites
with Microscope VHX-2000 manufactured by KEYENCE CORPORATION at a
magnification at which the crimp form of a single yarn can be
recognized. In each of the 10 images, 10 core yarns and 10 sheath
yarns were observed. A yarn having a spirally swirling form (spiral
structure) was determined as having a three-dimensional crimped
structure (described as "present" in the description of the
examples and comparative examples and in Tables 1, 2, and 3), and a
yarn not having a spiral structure was determined as not having a
crimped structure (described as "absent" in the description of the
examples and comparative examples and in the tables). In addition,
in the same images as described above, the radius of the curvature
6 (FIG. 3) of a crimped single yarn was measured with image
processing software (WINROOF). The radii of the 100 core yarns and
100 sheath yarns randomly selected as described above were measured
up to the second decimal place in millimeters, and the simple
average of the measured values was obtained. The simple average was
rounded off to the first decimal place, and the obtained value was
taken as the radius of curvature of the three-dimensional crimped
structure.
[0112] E. Coefficient of Static Friction Between Fibers
[0113] The coefficient of static friction between fibers was
measured with a radar type coefficient of friction tester according
to JIS L 1015 (2010). It should be noted that no pretreatment such
as opening was carried out, and the coefficient of static friction
between fibers was evaluated by arranging samples in parallel into
a cylinder.
[0114] F. Unwinding Properties (Effect of Suppressing
Entanglement)
[0115] A drum on which 500 m or more of a textured yarn is wound
was placed on a creel, and the textured yarn was unwound in the
cross-sectional direction of the drum at a speed of 30 m/min for 5
minutes. The disarrayed yarn and yarn tangle due to the
entanglement were visually confirmed and evaluated on the following
four scales.
[0116] A: No disarrayed yarn is observed and the yarn can be
satisfactorily unwound.
[0117] B: Slight disarrayed yarn is observed, but the yarn can be
unwound without problem.
[0118] C: Disarrayed yarn and slight yarn tangle are observed, but
the yarn can be unwound.
[0119] D: Disarrayed yarn and yarn tangle are observed, and the
yarn cannot be unwound.
[0120] G. Touch
[0121] A drum on which 500 m or more of a textured yarn is wound
was placed on a creel, and the textured yarn was unwound and wound
into a skein having a length of 10 m in the cross-sectional
direction of the drum with a measuring machine. One position of the
skein was fixed to prepare a sample for texture evaluation. The
touch of the sample when gripped was evaluated on the following
four scales.
[0122] A: The sample is excellent in bulkiness and flexibility, and
has an excellent texture without feeling of a foreign body.
[0123] B: The sample has a good texture with bulkiness and
flexibility.
[0124] C: The sample has bulkiness, and has a good texture without
feeling of a foreign body.
[0125] D: The sample has no bulkiness, and has a poor texture with
feeling of a foreign body.
[0126] H. Intrinsic Viscosity (IV) of Polymer
[0127] In 10 mL of o-chlorophenol having a purity of 98% or more at
a temperature of 25.degree. C., 0.8 g of the polymer to be
evaluated was dissolved, and the intrinsic viscosity (IV) of the
polymer was determined with an Ostwald viscometer at a temperature
of 25.degree. C.
Example 1
[0128] Polyethylene terephthalate (PET: IV=0.65 dl/g) was melted at
290.degree. C., weighed, charged into a spinning pack, and
discharged from a discharge hole for a hollow cross section having
3 slits (width: 0.1 mm) in concentric sectors as shown in FIG. 6.
Cooling air at 20.degree. C. was blown to one side of the
discharged thread at a flow of 100 m/min to cool and solidify the
thread. A nonionic spinning oil agent was applied to the thread,
and an unstretched yarn was wound up at a spinning speed of 1500
m/min. Then, the wound unstretched yarn was stretched 3.0 times
between rollers heated at 90.degree. C. and 140.degree. C. at a
stretching speed of 800 m/min to give a stretched yarn having a
fineness of 78 dtex, a number of filaments of 12, and a hollow rate
of 30%.
[0129] As shown in FIG. 4, each of two supply rollers was supplied
with one hollow section yarn, and the hollow section yarns were
sucked to the suction nozzle with one of the supply rollers running
at a speed of 50 m/min and the other running at a speed of 1000
m/min. In the suction nozzle, compressed air at an angle of
20.degree. with respect to the traveling thread was injected at an
air speed of 400 m/s, and the thread was ejected from the nozzle
together with the accompanying air stream so that the core yarn and
the sheath yarn would not twist with each other. The thread
injected from the nozzle was made to travel together with the air
stream for 1.0.times.10.sup.-4 seconds, and the thread path was
changed with use of a ceramic guide to give a textured yarn having
loops of the sheath yarn. The textured yarn was then taken up with
take-up rollers at 50 m/min.
[0130] Then, the textured yarn was led to a tube heater through the
rollers and heat-treated with heated air at 150.degree. C. for 10
seconds to set the form of the bulky yarn and develop a
three-dimensional crimp of the sheath yarn. The bulky yarn was
wound on a drum at 52 m/min with a tension control type winding
machine installed behind the tube heater.
[0131] The bulky yarn collected in Example 1 had a structure in
which loops of the sheath yarn protruded by 23.0 mm on average from
the center line of the textured yarn, and had the loops at a
frequency of 13/mm. The protruded loops were excellent in the
uniformity of size and period.
[0132] The sheath yarn formed loops and was fixed by being twisted
with the core yarn. The core yarn and the sheath yarn had a
three-dimensional crimped structure on the order of millimeters and
having a radius of curvature of 5.0 mm. No broken site was observed
in the sheath yarn, and the sheath yarn continuously formed loops.
(Number of broken sites: 0.0)
[0133] In the bulky yarn, the sheath yarn forming continuous loops
had a three-dimensional crimped structure, the coefficient of
static friction between fibers was 0.3, the bulky yarn had no
problem in the unwinding properties, and the bulky yarn was
smoothly unwound from the drum on which it is wound without causing
any yarn tangle or the like (unwinding properties: B). In addition,
the bulky yarn had a good texture with bulkiness derived from the
specific structure of the present invention (texture: B). The
results are shown in Table 1.
Example 2
[0134] A silicone oil agent containing polysiloxane at a
concentration of 8% by mass was uniformly sprayed to the bulky yarn
collected in Example 1 so that the final polysiloxane deposition
amount would be 1% by mass with respect to the bulky yarn. The
bulky yarn was heat-treated at a temperature of 165.degree. C. for
20 minutes to collect a bulky yarn of Example 2.
[0135] In Example 2, due to the formation of the silicone film, the
bulky yarn had a smoother touch than that of Example 1 did, and the
bulky yarn had a pleasant glossy feeling as well as the bulkiness
of the bulky yarn. The bulky yarn had a coefficient of static
friction between fibers of 0.1, which was found to be further lower
than that in Example 1. As a result of investigating the influence
of the silicone treatment on the form of the bulky yarn, the form
characteristics of the bulky yarn was roughly in agreement with the
form characteristics in Example 1, and other functions were
maintained. The bulky yarn was also excellent in the unwinding
properties and texture.
[0136] In addition to the unwinding properties, the bulky yarn was
easily separable. That is, when 10 bulky yarns each having a length
of 50 cm were cut and formed into a bundle, and both the ends of
the bundle were held and kneaded or rubbed, the sheath yarns were
not tangled with each other, and one bulky yarn was easily taken
out of the yarn bundle. The results are shown in Table 1.
TABLE-US-00001 TABLE 1 Example Example 1 2 Core yarn Type of
polymer -- PET PET Single yarn fineness dtex/F 6.5 6.5 Hollow rate
% 30 30 Sheath yarn Type of polymer -- PET PET Single yarn fineness
dtex/F 6.5 6.5 Hollow rate % 30 30 Fluid Feed speed Core yarn feed
speed m/min 50 50 processing Sheath yarn feed speed m/min 1000 1000
Fineness ratio Sheath/core fineness ratio -- 1.0 1.0 Nozzle Air
speed m/s 400 400 Air speed/yarn speed -- 480 480 Injection angle
.degree. 20 20 Intermingling and opening in nozzle -- absent absent
Turning point (distance/air speed) s 0.0001 0.0001 Silicone
Deposition amount % by mass 0 1 Bulky Loop Loop size mm 23.0 18.0
structure yarn Twist point number/mm 13 10 Loop breakage -- absent
absent (number of breaking points (number/mm)) (0.0) (0.0) Core
yarn Three-dimensional crimp -- present present Radius of curvature
mm 5.0 4.7 Sheath yarn Three-dimensional crimp -- present present
Radios of curvature mm 5.0 4.5 Charac- Strength cN/dtex 4.2 3.5
teristics Elongation % 31 38 Coefficient of static friction between
fibers -- 0.3 0.1 Unwinding properties (effect of suppressing
entanglement) -- B A Touch -- B A Remarks
Comparative Examples 1 and 2
[0137] In order to verify the effect of the bulky processing of the
present invention, the same operation as in Example 1 was carried
out except that a nozzle whose injection angle of compressed air
was changed to 90.degree. was used, and no turning point of the
ceramic guide was provided. In Comparative Example 1, however,
since the core yarn and the sheath yarn were excessively tangled
with each other at the same flow rate of compressed air as in
Example 1, and stable yarn processing was difficult due to clogging
of the nozzle, the air speed was reduced to 200 m/s, which was half
of that in Example 1. As a result, the yarn became capable of
traveling. Thus, the obtained textured yarn was collected, and the
characteristics were evaluated (Comparative Example 1).
[0138] In the textured yarn of Comparative Example 1, the size of
the loops of the sheath yarn was smaller than that in Example 1
before the heat treatment, and the loops were formed in a very
short period. Therefore, the textured yarn was heat-treated to be
crimped, but the textured yarn was poor in bulkiness although the
sheath yarn had loops. When the loops of the sheath yarn were
observed in detail, the loop size was uneven, and a relatively
large number of breaking points which had not been recognized in
the textured yarn picked out before the heat treatment were
observed (broken sites: "present", number of breaking points:
0.5).
[0139] With use of the textured yarn obtained in Comparative
Example 1, untwisting treatment was carried out by scratching the
textured yarn with a pair of rubber discs (Comparative Example 2).
Although the bulkiness seemingly improved, the breakage of the
loops was further increased as compared with Comparative Example 1,
the tanglement between the sheath yarns was promoted, and the
textured yarn gave a feeling of a foreign body when being
compressed. In addition, as compared with Comparative Example 1,
the yarn tangles increased, and the textured yarn was poor in
unwinding properties at the time of unwinding. The results are
shown in Table 2.
Comparative Example 3
[0140] With use of the textured yarn of Comparative Example 1,
silicone treatment was carried out in the same manner as in the
treatment carried out in Example 2 to give a textured yarn of
Comparative Example 3.
[0141] As compared with Comparative Example 1, although the
textured yarn showed a tendency toward improvement in unwinding
properties due to the slidability of silicone, the form of the
obtained textured yarn was not largely changed, and the textured
yarn had small loops in a short period. As a result, the textured
yarn was poor in swelling feeling and also poor in the texture as
compared with that in Example 2. The results are shown in Table
2.
Comparative Example 4
[0142] In order to verify the effect of the bulky processing of the
present invention, the same operation as in Comparative Example 3
was carried out except that a nozzle whose injection angle of
compressed air was changed to 60.degree. was used, and the ceramic
guide was arranged so that the yarn can be discharged immediately
after the discharge hole of the nozzle.
[0143] In Comparative Example 4, before the heat treatment,
small-sized loops and relatively large-sized loops were mixed.
Although the core yarn and the sheath yarn contracted due to the
heat treatment and a three-dimensional crimped structure was
developed, the textured yarn was greatly reduced in the overall
bulkiness as compared with Example 1. In addition, the unevenness
of the loops before the heat treatment was promoted, and a site
where the loops were partially slackened was observed. In addition,
since the injection angle of the compressed air was large, the yarn
was intermingled and opened in the nozzle, and the yarn was
deteriorated due to scratching of the single yarn against the inner
wall of the nozzle at high frequency. For this reason, after the
heat treatment, the breaking points of the loops were partially
observed although the textured yarn showed a small tendency toward
improvement as compared with Comparative Example 3. The results are
shown in Table 2.
TABLE-US-00002 TABLE 2 Comparative Comparative Comparative
Comparative Example Example Example Example 1 2 3 4 Core yarn Type
of polymer -- PET PET PET PET Single yarn fineness dtex/F 6.5 6.5
6.5 6.5 Hollow rate % 30 30 30 30 Sheath yarn Type of polymer --
PET1 PET1 PET1 PET1 Single yarn fineness dtex/F 6.5 6.5 6.5 6.5
Hollow rate % 30 30 30 30 Fluid Feed speed Core yarn feed speed
m/min 50 50 50 50 Sheath yarn feed speed m/min 1000 1000 1000 1000
Fineness ratio Sheath/core fineness ratio -- 1.0 1.0 1.0 1.0 Nozzle
Air speed m/s 200 200 400 400 Air speed/yarn speed -- 240 240 480
480 Injection angle .degree. 90 90 90 60 Intermingling and opening
-- present present present present in nozzle Turning point
(distance/ s 0 0 0 0.0000025 air speed) Silicone Deposition amount
% by mass 0 0 1 1 Bulky Loop Loop size mm 1.0 2.8 2.0 5.0 structure
Twist point number/mm 73 54 75 49 yarn Loop breakage -- present
present present present (Number of breaking (0.5) (0.7) (0.5) (0.4)
points (number/mm) Core yarn Three-dimensional crimp -- present
present present present Radius of curvature mm 4.7 4.8 4.6 4.1
Sheath yarn Three-dimensional crimp -- present present present
present Radius of curvature mm 4.2 4 4.5 4.8 Charac- Strength
cN/dtex 2.3 1.9 1.9 2.5 teristics Elongation % 21 18 32 29
Coefficient of static -- 0.5 0.6 0.4 0.4 friction between fibers
Unwinding properties -- D D D D (effect of suppressing
entanglement) Touch -- D D C C Remarks Strong rough touch Feeling
of Feeling of Feeling of Breakage occurred foreign body foreign
body foreign body due to Breakage Breakage entanglement of occurred
occurred sheath yarn
Examples 3 and 4
[0144] The same operation as in Example 2 was carried out except
that the feed speed was changed to 50 m/min for the core yarn and
500 m/min for the sheath yarn in Example 3, and 20 m/min for the
core yarn and 1000 m/min for the sheath yarn in Example 4.
[0145] In Example 3, the size of the loops was 12 mm and somewhat
smaller than that in Example 2, but the yarn was excellent in the
unwinding properties, and had a good texture.
[0146] In Example 4, although the loop size was 59 mm and larger
than that in Example 2, the loops had almost no slack. As for the
texture, the yarn had flexibility and excellent bulkiness.
Moreover, since the yarn had a structure in which the cutting and
slack of the sheath yarn were also suppressed, the yarn was good in
the unwinding properties. The results are shown in Table 3.
Example 5
[0147] A stretched yarn having a different single yarn fineness and
a different hollow rate (fineness: 78 dtex, number of filaments: 6
(single yarn fineness: 13 dtex), hollow rate: 20%) was collected by
yarn-making so as to have a hollow rate of 20% with use of a
different spinneret having 6 holes. The same operation as in
Example 1 was carried out except that the stretched yarn was used
as a sheath yarn.
[0148] In Example 5, due to the thicker sheath yarn, the rigidity
of the loops was improved, and a bulky yarn excellent in resilience
was obtained. Although the yarn was reduced in flexibility as
compared with Example 1, the yarn had sufficient bulkiness. In
actual use, the touch of the product can be adjusted by adjusting
the number of yarns to be doubled, and the yarn was at a level
without problem. The results are shown in Table 3.
Example 6
[0149] A stretched yarn having a different single yarn fineness and
a different hollow rate (fineness: 78 dtex, number of filaments: 24
(single yarn fineness: 3.3 dtex), hollow rate: 40%) was collected
with use of a different spinneret having 24 discharge holes for a
hollow cross section having 4 slits each 0.1 mm in width in
concentric circles for yarn-making. The same operation as in
Example 1 was carried out except that the stretched yarn was used
as a sheath yarn.
[0150] In Example 6, the loops of the sheath yarn were
self-supporting due to the twisting with the core yarn, and the
sheath yarn was thinner than that in Example 1. As a result, the
bulky yarn was excellent in flexibility. As the number of filaments
of the sheath yarn increased and the radius of curvature of the
crimp decreased (1.5 mm), some disarrayed yarn was seen at the time
of unwinding from the drum. However, the disarrayed yarn was
eliminated by adjusting the winding tension on the drum, and the
yarn was at a level without problem in practical use. The results
are shown in Table 3.
TABLE-US-00003 TABLE 3 Example Example Example Example 3 4 5 6 Core
yarn Type of polymer -- PET PET PET PET Single yarn fineness dtex/F
6.5 6.5 6.5 6.5 Hollow rate % 30 30 30 30 Sheath yarn Type of
polymer -- PET PET PET PET Single yarn fineness dtex/F 6.5 6.5 13.0
3.3 Hollow rate % 30 30 30 40 Fluid Feed speed Core yarn feed speed
m/min 50 20 50 50 Sheath yarn feed speed m/min 500 1000 1000 1000
Fineness Sheath/core fineness ratio -- 1.0 1.0 2.0 0.5 Air Air
speed m/s 400 400 400 400 Air speed/yarn speed -- 480 1200 480 480
Injection angle .degree. 20 20 20 20 Intermingling and opening in
nozzle -- absent absent absent absent Turning point (distance/air
speed) s 0.0001 0.0001 0.0001 0.0001 Silicone Deposition amount %
by mass 1 1 0 0 Bulky Loop Loop size mm 11.7 58.5 23.4 23.4
structure yarn Twist point number/mm 13 10 2 18 Loop breakage --
absent absent absent absent (number of breaking points (number/mm)
(0.0) (0.1) (0.0) (0.2) Core yarn Three-dimensional crimp --
present present present present Radius of curvature mm 4.7 4.7 5.0
4.9 Sheath yarn Three-dimensional crimp -- present present present
present Radius of curvature mm 4.5 4.5 1.5 13 Charac- Strength
cN/dtex 3.9 4.0 3.7 4.3 teristics Elongation % 38 39 35 32
Coefficient of static friction between fibers -- 0.1 0.2 0.2 0.3
Unwinding properties -- A B A C (effect of suppressing
entanglement) Touch -- B A C A Remarks
Example 7
[0151] A stretched yarn was collected under the same conditions as
in Example 1 with use of a different spinneret having 12 round
holes so that general round section fibers would be obtained, and
the yarn was spun while being excessively cooled from one side with
cooling air at 20.degree. C. in the same manner as in Example 1.
The crimp form of the collected stretched yarn after the heat
treatment was loose as compared with that in Example 1, and the
radius of curvature of the crimp was 28 mm. The same operation as
in Example 2 was carried out except that the stretched yarn was
used as a sheath yarn.
[0152] In Example 7, since the crimp form of the sheath yarn was
loose, the loops of the sheath yarn had a tufted shape, and the
yarn had an excellent texture having moderate resilience. The
results are shown in Table 4.
Example 8
[0153] The same operation as in Example 7 was carried out except
that the round section fibers used in Example 7 were used not only
in the sheath yarn but also in the core yarn.
[0154] Also in Example 8, since a loose crimp form of the sheath
yarn was developed, loops of the sheath yarn formed a tufted
structure. In addition, since the crimp form of the core yarn was
loose, the binding at the twist point between the core yarn and the
sheath yarn was weak, and even when a load was applied to the bulky
yarn in the fiber axis direction, the sheath yarn was capable of
moving laterally. At the time of unwinding, the yarn was sometimes
tangled due to the lateral movement although at a lower frequency
than in Example 7, but the yarn was at a level without problem in
practical use. The results are shown in Table 4.
Comparative Example 5
[0155] In order to verify the effect of the three-dimensional crimp
form of the core yarn and the sheath yarn, yarn processing was
carried out with a core yarn and a sheath yarn that were made under
different conditions from those in Example 2.
[0156] First, the core yarn was made with a spinneret for general
round section fibers used in Example 7, the sheath yarn was made
with a spinneret having a discharge hole for a hollow cross section
having 3 slits each 0.1 mm in width in concentric circles used in
Example 1, and the speed of the cooling air was changed to 20
m/min. A stretched yarn was collected in the same manner as in
Example 1 except for the above-mentioned conditions. Both the
stretched yarn for the core yarn and the stretched yarn for the
sheath yarn had a fineness of 78 dtex and a number of filaments of
12, and did not develop the three-dimensional crimp form in the
present invention even after the heat treatment. A textured yarn
was collected in the same manner as in Example 1 except that these
stretched yarns were used.
[0157] In Comparative Example 5, although it was possible to form
loops by providing a turning point outside the nozzle, the crimp of
the sheath yarn did not develop even after the heat treatment, and
the sheath yarn maintained the straight form. In addition, because
the sheath yarn did not develop the crimp, the loop size was uneven
as compared with that in Comparative Example 1, and the loops were
partially slackened.
[0158] In Comparative Example 5, since the sheath yarns had loops
even though they did not develop the three-dimensional crimp, the
sheath yarns tended to be tangled with each other more easily than
in Example 1, and a lot of yarn tangles were observed at the time
of unwinding. In addition, since the textured yarn unwound from the
drum underwent compressive deformation, the loops were fatigued and
fixed in the state of being laterally slid. Thus, the textured yarn
was reduced in the bulkiness. The results are shown in Table 4.
Comparative Example 6
[0159] Low viscosity PET (IV=0.51 dl/g) and polytrimethylene
terephthalate (3GT) (IV=1.20 dl/g) were prepared, and melted at
280.degree. C. Then, the materials were weighed so that they would
be compounded at a ratio of low viscosity PET/3GT=50/50, poured
into a spinning pack having a bonding type composite spinneret, and
a composite polymer flow was discharged. Then, cooling air at
20.degree. C. was blown to the thread at a rate of 20 m/min, the
thread was cooled and solidified, and an oil agent was imparted to
the thread. Then, an unstretched yarn was wound at a spinning speed
of 1500 m/min. Then, the wound unstretched yarn was stretched 3.0
times between rollers heated at 90.degree. C. and 130.degree. C. at
a stretching speed of 800 m/min to give a stretched yarn of
side-by-side composite fibers having a fineness of 78 dtex and a
number of filaments of 12. A textured yarn was collected according
to Comparative Example 1 except that the stretched yarn was used as
a sheath yarn and the round section fibers used in Comparative
Example 5 were used as a core yarn.
[0160] In the sample of Comparative Example 6, although the sheath
yarn developed a three-dimensional crimp form after the heat
treatment, the sheath yarn had a very small radius of curvature of
several tens of micrometers, and the sheath yarn was broken at some
sites (broken sites: "present", 0.4/mm). In addition, the loops of
the sheath yarn were greatly reduced in size as compared with the
loops before the heat treatment due to the development of the crimp
form, and the number of loops having a distance exceeding 0.6 mm
from the center line of the textured yarn was small. For this
reason, the textured yarn had a unique rubber-like touch, but did
not have the bulkiness and flexibility which are the objects of the
present invention. In addition, due to the fine crimp on the order
of micrometers, breakage of the sheath yarn, and uneven protrusion
of the loops, the coefficient of static friction between fibers was
relatively high (0.4), and the unwinding properties of the drum
were not good. The results are shown in Table 4.
TABLE-US-00004 TABLE 4 Comparative Comparative Example Example
Example Example 7 8 5 6 Core yarn Type of polymer -- PET PET PET
PET Single yarn fineness dtex/F 6.5 6.5 6.5 6.5 Hollow rate % 30 0
30 0 Sheath yarn Type of polymer -- PET PET PET1 PET/3GT Single
yarn fineness dtex/F 6.5 6.5 6.5 6.5 Hollow rate % 0 0 30 0 Fluid
Feed speed Core yarn feed speed m/min 20 50 50 50 processing Sheath
yarn feed speed m/min 1000 1000 1000 1000 Fineness ratio
Sheath/core fineness ratio -- 1.0 1.0 1.0 10 Air Air speed m/s 500
300 400 200 Air speed/yarn speed -- 1500 360 480 240 Injection
angle .degree. 20 45 90 90 Intermingling and opening in nozzle --
absent absent present present Turning point (distance/air speed) s
0.00011 0.00005 0.0001 0 Silicone Deposition amount % by mass 1 1 1
0 Bulky Loop Loop size mm 58.5 23.4 19.0 0.6 structure Twist point
number/mm 20 9 69 93 yarn Loop breakage Presence or absent absent
present present (Number of breaking points (number/mm) absence
(0.0) (0.0) (0.4) (0.4) Core yarn Three-dimensional crimp Presence
or present present absent absent absence Radius of curvature mm 5.0
4.8 absent absent Sheath yarn Three-dimensional crimp Presence or
present present absent present absence Radius of curvature mm 28
5.0 absent 0.3 Bulky Charac- Strength cN/dtex 3.7 4.3 2.4 1.4
structure teristics Elongation % 36 25 18 33 yarn Coefficient of
static friction between fibers -- 0.3 0.1 0.6 0.4 Unwinding
properties -- C A D C (effect of suppressing entanglement) Touch --
B B C D Remarks Feeling of Poor in foreign body bulkiness Breakage
occurred
DESCRIPTION OF REFERENCE SIGNS
[0161] 1: Sheath yarn [0162] 2: Core yarn [0163] 3: Center line of
textured yarn [0164] 4: Thread guide [0165] 5: Distance from center
line of textured yarn to apex of loop [0166] 6: Three-dimensional
crimp [0167] 7: Supply roller [0168] 8: Synthetic fiber [0169] 9:
Suction nozzle [0170] 10: Turning point [0171] 11: Textured yarn
[0172] 12: Take-up roller [0173] 13: Heater [0174] 14: Delivery
roller [0175] 15: Winder [0176] 16: Injection angle of compressed
air [0177] 17: Slit-shaped discharge hole
* * * * *