TECHNICAL FIELD
[0001] The present invention relates to a bulky yarn having a large number of loops in the
surface layer. The bulky yarn can be applied in a wide variety of fields from clothing
to industrial resources applications because the bulky yarn can appeal high heat retaining
properties with exhibiting a soft touch feeling.
BACKGROUND ART
[0002] Synthetic fibers made from thermoplastic polymers such as polyesters and polyamides
have characteristics that they have good basic characteristics such as mechanical
properties and dimensional stability, and are excellent in the balance of such characteristics.
Therefore, fiber materials utilizing thermoplastic polymers can have various structural
forms by high-order processing in addition to being capable of exhibiting polymer
properties and basic performance exhibited by yarn making, and are widely used not
only in clothing applications but also in interior decorations, vehicle interior decorations,
and industrial applications.
[0003] It is no exaggeration to say that technological innovation related to synthetic fibers
has been made based on a motivation for imitating natural materials, and various technical
proposals have been made for exhibiting functions originating from natural complex
structural forms with synthetic fibers. For example, there are various technical proposals
such as the manifestation of unique texture (friction, flexibility) by imitating the
cross section of silk, structural coloring typified by morpho butterflies, and water
repellent performance seen in leaves of lotus. One of them is an approach to exhibit
functions such as soft texture and lightweight and heat retaining properties provided
by natural feathers.
[0004] As the natural feathers, 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 exhibit excellent lightweight and heat retaining properties owing to their
special structural form formed of keratin fibers. For this reason, functions of products
including natural feathers as filling have been recognized by even general users,
and the natural feathers are widely used in bedclothes and clothing items such as
jackets.
[0005] Capture of waterfowls, however, is limited from the viewpoint of nature conservation,
and the total production of natural feathers is restricted. Furthermore, due to the
recent abnormal weather and occurrence of the plague, there is a problem that the
supply of natural feathers largely fluctuates, and is also a problem of price increase
and unstable supply. In addition, despite the number of steps for the use of natural
feathers, 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 feathers
in Europe and other countries. For this reason, attention is being paid to a filling
material made of synthetic fibers that is capable of stable supply.
[0006] Many filling materials made of synthetic fibers have been proposed from long ago,
but there are no filling materials comparable to natural feathers in terms of basic
characteristics such as the bulkiness, compression recovery, and soft texture.
[0007] For example, as shown in Patent Documents 1 and 2, by making the fiber aggregate
state spherical or radial, the bulkiness derived from the structure is improved.
[0008] Conventionally used yarn processing techniques intended for adding high value to
fibers have been generally known to be capable of manufacturing a textured yarn having
bulkiness by subjecting the fibers to twisting and then to untwisting, 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 filling material based on the bulkiness
and soft texture of the textured yarns.
[0009] In Patent Document 3, 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 twisting to form loops in the surface layer by the swayed
fibers. After that, the fibers are untwisted by further being abraded with two discs
or the like to provide a bulky textured yarn. Indeed, with this technique, there is
a possibility of providing a bulky yarn having loops formed by a sheath yarn by adjusting
the degree of yarn swaying or the like according to the conventional method.
[0010] Patent Document 4 discloses a technique in which an excessively supplied sheath yarn
is fixed by a yarn length difference by injecting compressed air from a direction
perpendicular to the traveling yarn within an entangling nozzle, and opening and entangling
the fiber. In Patent Document 4, it is possible to provide an entangled yarn having
bulkiness in which sheath yarns having a loop shape are present in the surface layer.
PRIOR ART DOCUMENTS
PATENT DOCUMENTS
[0011]
Patent Document 1: Japanese Patent Publication No. 48-7955
Patent Document 2: Japanese Patent Publication No. 51-39134
Patent Document 3: Japanese Patent Laid-open Publication No. 2011-246850
Patent Document 4: Japanese Patent Laid-open Publication No. 2012-67430
SUMMARY OF THE INVENTION
PROBLEMS TO BE SOLVED BY THE INVENTION
[0012] Those shown in Patent Documents 1 and 2 cause a foreign body sensation when compressed
and are not comparable to natural feathers from the viewpoint of soft texture of natural
feathers. In these fiber structures mainly composed of short fibers, the bulkiness
and flexibility (compression recovery) of the structure are provided by the mechanical
properties and the fineness (thickness) of the fibers used. For this reason, further
improvements are required to achieve both the conflicting properties, that is, bulkiness
and flexibility, like natural feathers do.
[0013] In Patent Document 3, in the case where twisting is applied to the loop yarn from
which the sheath yarn partially protrudes and the yarn is untwisted while abraded
with rubber or the like by a mechanical kneading machine, the protruding loop is partly
broken or deteriorated. When the textured yarn is used as a filling material, several
to several tens of yarns are finally bundled and filled. Therefore, the deteriorated
part (fluff) is remarkably entangled with the sheath yarn of other textured yarns.
When this entangled sheath yarn is filled, it causes a foreign body sensation to deteriorate
the texture or promotes entanglement, so that the bulkiness may decrease over time.
[0014] In Patent Document 4, in the case of intermingling the traveling threads in the nozzle,
and opening and entangling the fibers, the traveling yarns sway in a very short period
to cause entanglement 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 entangled with the core yarn, the size of the loops varies
in the fiber axis direction, and the yarn is restricted in the bulkiness. Further,
the loop yarn formed in the nozzle stays inside the nozzle, and is discharged to the
outside of the nozzle by the jet 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 difficulties in the process passability in the high-order processing and that the
portion where the sheath yarns are tangled with each other leads to a foreign body
sensation.
[0015] In the case of using the textured yarns as described in Patent Documents 3 and 4
as the filling material, in addition to the problems relating to bulkiness and texture
described above, both ends of the textured yarn are to be fixed for use to suppress
entanglement and twist. However, in the textured yarns described in Patent Documents
3 and 4, since the textured yarn itself does not have extensibility, the entangled
yarn fixed at a fixed length is in a state of being stretched in the filling material.
Therefore, if the design or size is so tight, there are cases where an uncomfortable
restraint feeling is produced. In particular, when clothing and the like are produced
with the yarns, because elbows, knees, neck, and waist circumference parts that are
largely moved need to be designed with a margin, extra spaces are formed. Therefore,
there are cases where functions such as heat retaining properties cannot be exhibited
sufficiently.
[0016] For this reason, a bulky yarn that has extremely high bulkiness provided by loops,
suppresses entanglement between textured yarns, and has good stretchability is desired.
[0017] An object of the present invention is to provide a bulky yarn suitable for high-performance
heat retaining materials.
SOLUTIONS TO THE PROBLEMS
[0018] The above-mentioned object is achieved by the following means.
- (1) A bulky yarn including: a sheath yarn that has continuously formed loops without
any breakages; and a core yarn that substantially fixes the sheath yarn by being interlaced
with the sheath yarn, wherein a number of loops protruding from a yarn surface layer
by not less than 3.0 mm is in a range of 1 to 30 loops/mm, an elastic modulus is not
greater than 80 cN/dtex, and an extension recovery rate at a time of 10% extension
recovery is not less than 50%.
- (2) The bulky yarn according to (1), wherein a single yarn fineness of a constituent
fiber is not less than 3.0 dtex, and a single yarn fineness ratio of the sheath yarn
to the core yarn (sheath/core) is in a range of 0.5 to 2.5.
- (3) The bulky yarn according to (1) or (2), wherein the core yarn is a side-by-side
or eccentric core-in-sheath conjugate fiber, and a fiber that constitutes the sheath
yarn is a three-dimensional crimped structure yarn having a curvature radius of 2.0
mm to 30.0 mm.
- (4) The bulky yarn according to (1) or (2), including: a sheath yarn that has formed
loops; and a core yarn that substantially fixes the sheath yarn by being interlaced
with the sheath yarn, wherein the sheath yarn has continuously formed loops substantially
without any breakages and is a conjugate fiber having a density of less than 1.00
g/cm3.
- (5) The bulky yarn according to (4), wherein the sheath yarn has a three-dimensional
crimped structure.
- (6) The bulky yarn according to (4) or (5), wherein the sheath yarn is an islands-in-sea
conjugate fiber having a hollow cross section with a hollow rate of not less than
20%.
- (7) The bulky yarn according to (6), wherein an island component in the islands-in-sea
conjugate fiber contains a polyolefin and a sea component in the islands-in-sea conjugate
fiber contains a polyester.
- (8) The bulky yarn according to (1) or (2), including: a sheath yarn that has formed
loops and a three-dimensional crimped structure; and a core yarn that substantially
fixes the sheath yarn by being interlaced with the sheath yarn, wherein a 10% modulus
is less than 1.5 cN/dtex, a fiber extension ratio at load application is not less
than 1.1, and a fiber length restoration rate after load application extension is
80 to 100%.
- (9) The bulky yarn according to (8), wherein the fiber extension ratio at load application
is not less than 1.5, and the fiber length restoration rate after load application
extension is 90 to 100%.
- (10) The bulky yarn according to any one of (1) to (9), wherein a coefficient of static
friction between fibers is not greater than 0.3.
- (11) The bulky yarn according to any one of (1) to (10), wherein both the core yarn
and the sheath yarn are composed of hollow cross-section fibers with a hollow rate
of not less than 20%.
- (12) A fiber product including the bulky yarn according to any one of (1) to (11)
in at least a part of the fiber product.
EFFECTS OF THE INVENTION
[0019] The bulky yarn of the present invention exhibits an excellent touch feeling without
a foreign body sensation, excellent lightweight and heat retaining properties and
the like because it has a unique bulky structure in which loops having a three-dimensional
crimped form are formed in the surface layer, and thus entanglement between bulky
yarns is suppressed. Because the bulky yarn of the present invention also has comfortable
stretchability that allows the bulky yarn to extend and deform under low stress, the
bulky yarn of the present invention is excellent in adherence as well as a movement
following ability which enables flexible extension and deformation in accordance with
a movement, and does not produce any unnecessary space. Therefore, the bulky yarn
of the present invention can be utilized as a high-performance and lightweight heat
retaining material that is excellent in a wearing feeling and heat retaining functions
although it is compact.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020]
Fig. 1 shows a schematic side view of an example of the bulky yarn of the present
invention.
Fig. 2 shows a schematic diagram for illustrating a yarn surface measuring method.
Fig. 3 shows a schematic diagram for illustrating a three-dimensional crimped (spiral)
structure.
Fig. 4-1 shows a schematic diagram of an example of a cross section of a side-by-side
conjugate yarn that constitutes the bulky yarn of the present invention, and Fig.
4-2 shows a schematic diagram of an example of a cross section of an eccentric core-in-sheath
conjugate yarn that constitutes the bulky yarn of the present invention.
Fig. 5 shows a schematic diagram of an example of a cross section of a hollow islands-in-sea
conjugate yarn that constitutes the bulky yarn of the present invention.
Fig. 6 shows a schematic process diagram schematically showing an example of a method
for manufacturing the bulky yarn of the present invention.
Fig. 7 shows a schematic side view for illustrating a suction nozzle used in the method
for manufacturing the bulky yarn of the present invention.
Fig. 8 shows a schematic cross-sectional view for illustrating a discharge hole of
a hollow cross-section spinneret used in the method for manufacturing the bulky yarn
of the present invention.
EMBODIMENTS OF THE INVENTION
[0021] Hereinafter, the present invention will be described in detail together with preferable
embodiments.
[0022] The bulky yarn of the present invention is a bulky yarn including: a sheath yarn
that has continuously formed loops without any breakages; and a core yarn that substantially
fixes the sheath yarn by being interlaced with the sheath yarn, wherein a number of
loops protruding from a yarn surface layer by not less than 3.0 mm is in a range of
1 to 30 loops/mm, an elastic modulus is not greater than 80 cN/dtex, and an extension
recovery rate at a time of 10% extension recovery is not less than 50%.
[0023] The bulky yarn of the present invention includes a sheath yarn that has formed loops
and a core yarn that substantially fixes the sheath yarn by being interlaced with
the sheath yarn. In the present invention, the sheath yarn has continuously formed
loops without any breakages.
[0024] The bulky yarn of the present invention is suitably made of synthetic fibers from
the viewpoint of process passability during bulky processing and making use of the
characteristics of the present invention in actual use. The term "synthetic fibers"
as used herein refers to fibers made of high molecular weight polymers. Among high
molecular weight polymers, melt-moldable thermoplastic polymers are suitably used
in the present invention because the fibers used in the present invention can be manufactured
in a highly productive melt spinning method.
[0025] Herein, examples of the thermoplastic polymers include melt-moldable polymers such
as polyethylene terephthalate or a copolymer thereof, polyethylene naphthalate, polybutylene
terephthalate, polytrimethylene terephthalate, polyolefins, polycarbonates, polyacrylates,
polyamides, polylactic acids, and thermoplastic polyurethanes.
[0026] Among these thermoplastic polymers, polycondensation polymers typified by polyesters
and polyamides are suitable because these polymers are crystalline polymers, have
high melting points, and thus do not deteriorate or flatten even when they are heated
at relatively high temperature in subsequent processes, a molding process, and actual
use. From the viewpoint of heat resistance, the melting point of the polymer is preferably
not less than 165°C.
[0027] From the viewpoint of improving the lightweight properties of the bulky yarn of the
present invention, it is more preferably that low density polypropylene, which is
a polyolefin, be at least partially used. The molecular weight of polypropylene to
be used is suitably high in order to provide, in addition to lightweight properties,
anti-flattening properties against compression, and the melt flow rate (MFR), which
is an index of the molecular weight of polypropylene, is preferably not greater than
20 g/10 min. The MFR herein is the amount of the resin extruded per 10 minutes measured
according to the method described in JIS K 7210: 1999, and the MFR generally tends
to decrease as the molecular weight of the resin increases. When the MFR of the polypropylene
to be used falls within the above-mentioned range, the bulky yarn is less likely to
be flattened by the compression and bending applied to the bulky yarn during use,
and can sufficiently withstand the impact undergone during processing. Therefore,
the bulky yarn has no problem in process passability. When polypropylene is used in
at least a part of the bulky yarn of the present invention, polypropylene containing
an antioxidant is particularly preferably used to prevent oxidation and heat generation
in the case where the bulky yarn is used in clothing and the like.
[0028] The polymer used in the present invention can contain various additives such as inorganic
substances such as titanium oxide, silica, and barium oxide, colorants such as carbon
black, dyes, and pigments, flame retardants, fluorescent whitening agents, antioxidants,
and ultraviolet absorbers.
[0029] The bulky yarn of the present invention, as illustrated in Fig. 1, includes a sheath
yarn (reference sign 1 in Fig. 1) that has formed loops and a core yarn (reference
sign 2 in Fig. 1) that substantially fixes the sheath yarn by being interlaced with
the sheath yarn.
[0030] The core yarn herein means a filament present within not greater than 0.6 mm from
a yarn surface (reference sign 3 in Fig. 2). The yarn surface means a straight line
connecting a pair of yarn path guides (reference sign 4 in Fig. 2) when a fixed length
of a textured yarn is threaded between the yarn path guides 4. The filament present
within a distance not greater than 0.6 mm from the yarn surface (reference sign 5
in Fig. 2) is the core yarn of the present invention, and is a base point of loops.
The filament protruding in a loop shape by not less than 3.0 mm from the surface of
the yarn is a sheath yarn referred to herein, which is responsible for the bulkiness
of the bulky yarn of the present invention. The present invention includes a core
yarn that substantially fixes the sheath yarn that has formed loops. The term "substantially
fix" as used herein means that the sheath yarn self-stands from the interlacing point
between the sheath yarn and the core yarn. The self-standing state refers to a state
in which the sheath yarn stands and forms loops in the outer layer direction of the
bulky yarn from the interlacing point between the sheath yarn and the core yarn. The
interlacing point with the core yarn, that is, the vicinity of the starting point
of a loop, is often actually in a state in which filament bundles twine each other
and are mixed with each other. Therefore, the point at which the sheath yarn that
forms an apex of a loop in a distance of not less than 3.0 mm from the yarn surface
intersects with a straight line positioned 0.6 mm from the yarn surface is defined
as an interlacing point.
[0031] The interlacing point plays a role of supporting the self standing of the loop formed
by the sheath yarn, which is a characteristic of the present invention The interlacing
points are preferably present at a moderate period. From this viewpoint, the number
of interlacing points between the sheath yarn and the core yarn in the bulky yarn
needs to be 1/mm to 30/mm. When the number falls within the above-mentioned range,
the distance between loops is appropriate and thus the stretchability (extension recovery),
which is an important element of the present invention, is not impaired. Further from
this viewpoint, the number of interlacing points is more preferably in a range of
5/mm to 15/mm to play the role of fixing the loop and exhibit good stretchability.
[0032] To determine the core yarn and the sheath yarn and continuously measure the number
of loops per unit length in the fiber axis direction of the textured yarn, a photoelectric
fluff detection device can be utilized. For example, the parts at 0.6 mm and 3.0 mm
from the yarn surface are evaluated under the conditions of a yarn speed of 10 m/min
and a traveling yarn tension of 0.1 cN/dtex using a photoelectric fluff measuring
machine (TORAY FRAY COUNTER).
[0033] The sheath yarn that has loops of the present invention is substantially fixed by
the core yarn and has a form protruding toward the outer layer in the cross section
of the textured yarn.
[0034] The term "protrusion of a loop" as used herein corresponds to the distance from the
surface of the yarn (reference sign 5 in Fig. 2). The distance is determined by two-dimensionally
observing the textured yarn threaded in a fixed length on a pair of yarn path guides
from one side of the textured yarn, and measuring the distance in the observed image.
Ten randomly selected textured yarns are photographed so that the entire loops can
be observed, and protrusions of loops at 10 points are photographed in each image.
This operation is performed for a total of 10 images, and a total of 100 points are
measured in units of millimeters up to the second decimal place. An average value
of these numerical values is calculated, and a value obtained by rounding off the
value to the first decimal place is taken as the loop size (protrusion) in the present
invention.
[0035] According to the studies made by the present inventors, the loop preferably protrudes
by a length in the range of not less than 3.0 mm and not greater than 100.0 mm from
the surface of the yarn. When the protrusion length falls within the above-mentioned
range, combined with the crimped structure of the sheath yarn, the bulkiness and the
entanglement suppression effect, that is, the object of the present invention, can
be achieved without problem. In consideration of processability of the bulky yarn
described below, the protrusion length is more preferably not less than 3.0 mm and
not greater than 70.0 mm. In consideration of repeated compression recovery deformation
under harsh environments such as the environments of sports clothing, the protrusion
length is more preferably not less than 5.0 mm and not greater than 60.0 mm.
[0036] Herein, the loop formed by the sheath yarn protrudes toward the outer layer from
the interlacing point on the core yarn as the starting point, and the shape of the
loop is preferably a kurunodaru shape (a teardrop shape) rather than an arched shape
formed by general entanglement. In the case of the kurunodaru-shaped loop, the loop
is substantially fixed at the interlacing point with the core yarn, and thus the loop
formed by the sheath yarn returns to its original shape more easily after compressive
deformation as compared to the arched loop. In the first place, the kurunodaru shape
is preferable to achieve the bulkiness with resilience. The sheath yarn preferably
has a three-dimensional crimped structure from the viewpoint of the suppression of
entanglement between sheath yarns. It was also found that by adopting this structure,
marked bulkiness can be exhibited due to the synergistic effect with the loop shape.
[0037] Meanwhile, the present inventors have found as a result of their investigation that
when the loop formed by the sheath yarn is broken halfway or partially deteriorated,
the above-mentioned effect tends to decrease. Therefore, it is important that the
sheath yarn be not broken halfway in the loop from the viewpoint of simultaneously
achieving contradictory properties, that is, bulkiness and suppression of entanglement,
which cannot be provided by conventional techniques.
[0038] The breakage can be confirmed by observing 10 points randomly selected from a textured
yarn at a magnification enabling the observation from the interlacing point between
the core yarn and the sheath yarn to the next interlacing point (the entire loop).
The state in which a sheath yarn has continuously formed loops without any breakages
in the present invention means that the average of the breakages of a total of 100
sheath yarns obtained by the observation of 10 sheath yarns at 10 observation points
is not greater than 0.2. When the average falls within the above-mentioned range,
sheath yarns having free yarn ends are substantially not present, and sheath yarns
can be present without being entangled with each other. In the case of subjecting
a yarn to twisting and then an untwisting step, or intermingling and opening the yarn
in a nozzle by strong air injection as in conventional methods, the traveling yarn
may be slammed into the inside of the nozzle made of metal at high frequency to be
broken or deteriorated. Further, when loops as in the present invention are to be
formed, it is necessary to abrade the yarn between rubber discs to untwist the yarn,
and thus the sheath yarn is broken or largely deteriorated. Therefore, the broken
sheath yarn twines around other sheath yarns or the sheath yarns are tangled with
each other to promote the fastener effect, resulting in constraining the structural
form and high-order processing of the textured yarn. In the present invention, these
problems are largely eliminated and the effect provided by the sheath yarn can be
sufficiently exhibited.
[0039] The sheath yarn of the present invention preferably has a three-dimensional crimped
structure. The three-dimensional crimped structure herein refers to a single yarn
of a filament having a spiral structure as illustrated in Fig. 3. This three-dimensional
crimp can be evaluated by picking up 10 or more single yarns at 10 points selected
randomly from a textured yarn, and observing each single yarn at a magnification enabling
the observation of the crimp form using a digital microscope or the like. In the image,
if the single yarn observed has a spirally swirling form, the yarn is judged to have
a three-dimensional crimped structure, and if the single yarn has a straight form,
the yarn is judged not to have a crimped structure.
[0040] To make the present invention more effective, the curvature radius of the three-dimensional
crimp of the sheath yarn is suitably on the millimeter order (10
-3 m) size rather than the micrometer order (10
-6 m) size, which is a size exhibited by a latent crimped yarn obtained by common manufacturing
methods such as conventional side-by-side conjugate fibers and hollow fibers. In the
present invention, the bulkiness and resilience in the circumferential direction and
cross-sectional direction of the textured yarn can be freely controlled by the size
of the three-dimensional crimp, and naturally, by utilizing this resilience, the entanglement
suppression of the sheath yarns, which is one of the objects of the invention, can
also be realized. In particular, when the size of the crimp is on the millimeter order,
the bulky yarn is excellent mainly from the viewpoint of the compatibility of bulkiness
and compressibility of the sheath yarn, and in addition, the balance between the bulkiness
and the suppression of entanglement.
[0041] In the present invention, the curvature radius of the spiral structure is preferably
in the range of 2.0 mm to 30.0 mm. The curvature radius of the spiral structure herein
is defined as the length corresponding to the radius of a perfect circle inscribed
most frequently at two or more points in a curve (reference sign 6 in Fig. 3) formed
by the fiber having the spiral structure in the image two-dimensionally observed with
a digital microscope or the like by the same method as in the above-mentioned determination
of the presence or absence of the three-dimensional crimp. Curvature radiuses of the
total of 100 single yarns are measured to the second decimal place in units of millimeters
by picking up 10 or more single yarns at 10 points randomly selected from the textured
yarn, and observing each single yarn with a digital microscope or the like at a magnification
enabling confirmation of the crimp shape. A simple average of these measured values
is calculated, and a value obtained by rounding off the value to the first decimal
place is taken as the curvature radius of the three-dimensional crimped structure
of the present invention.
[0042] The curvature radius is more preferably 2.0 mm to 20.0 mm. When the curvature radius
falls within this range, loops formed by the sheath yarn have crimps like a spring.
Therefore, the sheath yarn comes in contact with the core yarn at points while having
a moderate repulsion feeling against the compression in the cross-sectional direction
of the bulky yarn, and the bulky yarn exhibits very comfortable bulkiness. Further,
considering the balance with a loop having a high processability, which will be described
later, the curvature radius is particularly preferably in the range of 3.0 mm to 15.0
mm so that the effect of the present invention is well exhibited. Within this range,
the bulky yarn has no problem with long-term durability, and the effect of the present
invention effectively works when the bulky yarn is applied to clothing to which repeated
compression recovery is applied, especially sports clothing that is used under harsh
environments.
[0043] What is necessary for the exhibition of this effect is not a two-dimensional bending
that can be imparted by mechanical pushing or the like, but the three-dimensional
shape and a spiral or similar structure possessed by the single yarn itself. Conventionally,
these crimped forms are not applied to sheath yarns because the fastener phenomenon
due to the entanglement of the yarns is relatively likely to occur. This is because
the fibers mainly used are general latent crimped fibers having fine crimps on the
micrometer order. In this case, the fine spiral structures mutually penetrate into
each other, sometimes promoting the fastener effect.
[0044] Meanwhile, to achieve the suppression of entanglement between the textured yarns
of the present application, the present inventors pushed forward the study focusing
on the form of the original yarn. As a result, the present inventors discovered that,
in particular, when three-dimensional crimps on the millimeter order are formed in
a bulky yarn having loops, a phenomenon completely opposite to the conventional recognition
occurs. Such a phenomenon is thought to be caused by the synergistic effect with the
structure of loops formed by the sheath yarn because, due to three-dimensional crimps
of the sheath yarn, bulky yarns have volumes to exclude each other and entanglement
is largely suppressed even when bulky yarns are bundled. That is, the sheath yarn
of the bulky yarn of the present invention has a movable space depending on the size
of the loop. According to the definition of the present invention, the sheath yarn
has a relatively large hemispherical movable space having a radius of not less than
2.0 mm around the fixing point of the loop. In this case, single yarns having a three-dimensional
crimp with an overwhelmingly large size relative to the fiber diameter come into contact
with each other at points and repel each other so that they can be present independently
without entanglement. In a filament having three-dimensional crimps, in addition to
the movable space described above, the single yarn itself can further extend like
a spring in the fiber axis direction. Therefore, when single yarns cross each other,
the crossed part can be easily unwound by vibration. This phenomenon is a phenomenon
unique to the structural form, as in the bulky yarn of the present invention, in which
a sheath yarn has loops formed several times to several tens of times of the conventional
one. Furthermore, the three-dimensional crimp of the sheath yarn works effectively
also from the viewpoint of bulkiness, which is the basic characteristic of the present
invention. That is, the point contact between the sheath yarns described above produces
an effect of repelling each other even within a single textured yarn, maintaining
the state of being radially opened in the cross-sectional direction of the textured
yarn over time in addition to the initial bulkiness. The conventional simple straight
filament is difficult to achieve the behavior like a spring of the radially opened
sheath yarn of the present invention. In addition, such a behavior is generated by
mutual repulsion of the sheath yarns, and sheath yarns having three-dimensional crimps
support each other, thereby achieving the significant suppression of flattening of
the sheath yarn.
[0045] The morphological characteristics that the sheath yarn of the present invention has
formed loops and a three-dimensional crimped structure can also be seen as a decrease
in coefficient of friction. The decrease in coefficient of friction is an effect provided
by the point contact with others, as described above, and is one of the effects exhibited
by the bulky yarn having the specific structure of the present invention. According
to the investigation by the present inventors, the coefficient of static friction
between fibers is preferably not greater than 0.3 in order to suppress entanglement
between textured yarns while retaining bulkiness. The coefficient of static friction
between fibers is herein measured by a radar type coefficient of friction tester in
accordance with JIS L 1015 (2010). In the present invention, unless necessary, processing
such as fiber opening is not performed, and the textured yarns is evaluated by arranged
in parallel in a cylinder. The coefficient of static friction between fibers is suitably
low, more preferably not greater than 0.2, and particularly preferably not greater
than 0.1, because the texture is improved as the fiber slides and moves moderately
when the bulky yarn of the present invention is processed into a fiber product and
compressed.
[0046] The bulky yarn of the present invention has excellent bulkiness, and the yarn that
constitutes the bulky yarn suitably has moderate resilience. This resilience can be
regarded as the cross-sectional secondary moment of the fiber, and in consideration
of the intended effect of the present invention, the single yarn fineness of the constituent
synthetic fiber is preferably not less than 3.0 dtex. When used as filling, the bulky
yarn is deformed due to repeated compression recovery and the like. Therefore, the
constituent filaments preferably have moderate rigidity, and the single yarn fineness
is more preferably not less than 6.0 dtex. The fineness herein refers to a value calculated
from the obtained fiber diameter, number of filaments, and density, or a value obtained
by calculating the weight per 10,000 m from a simple average value obtained by measuring
the weight of a unit length of fibers a plurality of times. The substantial upper
limit of the single yarn fineness in the present invention is 50.0 dtex.
[0047] The single yarn fineness ratio of the sheath yarn to the core yarn (sheath/core)
is preferably in the range of 0.5 to 2.5 from the viewpoint of appealing a more excellent
touch feeling with the bulky yarn of the present invention. When the ratio falls within
the above-mentioned range, the sheath yarn and the core yarn have finenesses close
to each other, and the bulky yarn can be used without foreign body sensation or the
like when compressed. A range of the single yarn fineness ratio (sheath/core) enabling
efficient bulky processing is 0.7 to 1.5. The above-mentioned range is more preferable
in that the effect of the present invention becomes more remarkable. In the bulky
yarn of the present invention, various fibers can be combined. However, from the viewpoint
of the efficient fluid processing and no foreign body sensation at the time of compression
as described above, the core yarn and the sheath yarn are suitably fibers having the
same single yarn fineness and the same mechanical properties. Specifically, in the
present invention, it is suitable to prepare two or more drums of 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.
[0048] From the viewpoint of lowering of the coefficient of friction and suppression of
entanglement in such a textured yarn, it is preferable that the core yarn have a three-dimensional
crimped structure in addition to the sheath yarn. This is because also in the core
yarn, when the yarn is in a free state at the interlacing point of the core yarn that
substantially fixes the sheath yarn, a space between filaments derived from the three-dimensional
crimp of the core yarn is present, and in the case where such a textured yarn has
almost no tension, the loop of the sheath yarn can be skidded in a limited space also
in the fiber axis direction, and thus the movable space of the sheath yarn expands,
making the effect of entanglement suppression and soft texture of the present invention
more prominent. Meanwhile, when tension is applied to the textured yarn, the sheath
yarn extends, thereby exhibiting an effect in practical use, such as increase of the
binding force at the interlacing point, and prevention of the loosening of the loop
and the falling off of the sheath yarn. The three-dimensional crimp of the core yarn
can also be confirmed from the observation of the core yarn sampled randomly according
to the three-dimensional crimp evaluation method of the sheath yarn described above.
[0049] The bulky textured yarn of the present invention needs to have an elastic modulus
of not greater than 80 cN/dtex. Herein, the elastic modulus was calculated by obtaining
a stress-strain curve of the textured yarn under the conditions shown in JIS L1013
(1999), linearly approximating the initial rising portion of the curve, and finding
the slope of the line. This operation was performed on 5 samples for each level, and
a simple average value of the obtained results was obtained, and rounded off to the
first decimal place to obtain the elastic modulus.
[0050] This elastic modulus represents the rigidity at the time of extension deformation
of the textured yarn. When this value is too high, the textured yarn does not flexibly
extend and deform. Meanwhile, when the elastic modulus is not greater than 80 cN/dtex,
the textured yarn can be flexibly deformed while having an appropriate resistance
to the initial deformation force. Therefore, the textured yarn is excellent in movement
following ability, which is an object of the present invention. For example, when
a jacket is sewed with the yarn, it is naturally suitable to appropriately change
the characteristics of the sample depending on to the site. In particular, with respect
to the sites around the elbow and the knee that are often moved, the elastic modulus
is preferably not greater than 65 cN/dtex. Regarding the site such as neck circumference
or waist circumference in which rigidity can be an uncomfortable feeling of oppression,
it is particularly preferable to set the elastic modulus to not greater than 55 cN/dtex.
The substantial lower limit of the elastic modulus in the present invention is 10
cN/dtex.
[0051] To achieve the object of the present invention, it is an important requirement that
the extension recovery rate at 10% extension of the textured yarn is not less than
50%. Herein, the extension recovery rate can be evaluated by a tensile tester used
for evaluating the above-mentioned elastic modulus. That is, the textured yarn is
extended by 10% under conditions of a sample length of 20 cm and a tensile speed of
100%/min using a tensile tester, then left to stand for 1 minute, and recovered to
the original sample length at the same speed. This operation is repeated 10 times,
the stress-strain curve in this operation is recorded, and the length (S0) at 10%
extension and the length (S1) at which the stress reaches 0 are obtained to obtain
the extension recovery rate by the following formula. The same operation is performed
on 5 samples for each level, and a simple average value of the obtained results is
obtained, and rounded off to the nearest whole number to obtain the extension recovery
rate.
[S0: length at 10% extension, S1: length at which the stress reaches 0]
[0052] The bulky yarn of the present invention can exert its effect to the full extent especially
when it is applied to a part with high mobility. When the extension recovery rate
is not less than 50%, elastic properties and anti-flattening properties at repeated
extension recovery are excellent. The distortion applied repeatedly in the application
of the bulky textured yarn of the present invention is not greater than 10%, and the
textured yarn is suitably excellent in the extension recovery rate in such distortion.
Further, from this viewpoint, the higher the extension recovery rate defined herein
is, the closer it is to that of rubber elastic deformation, which means that the textured
yarn having high extension recovery rate is a material showing excellent stretchability.
The substantial upper limit in the present invention is 100%. When the bulky yarn
of the present invention is used in general clothing applications such as underwear
and outerwear or sleepwear such as bedclothes and pillows, the extension recovery
rate is preferably not less than 55%. It is particularly preferable that the extension
recovery rate be not less than 70% in sports clothing applications where the use situation
is relatively harsh.
[0053] The bulky yarn of the present invention preferably has a breaking strength of 0.5
to 10.0 cN/dtex and a degree of extension of 5 to 700%. Herein, the strength is a
value obtained by obtaining a load-extension curve of a textured yarn under the conditions
shown in JIS L 1013 (1999), and dividing the load value at break by the initial fineness.
The degree of extension is a value obtained by dividing the extension at break by
the initial sample length. To satisfy the process passability in high-order processing
processes and withstand practical use, the breaking strength of the bulky yarn of
the present invention is preferably not less than 0.5 cN/dtex, and the practicable
upper limit value is 10.0 cN/dtex. The degree of extension is preferably not less
than 5%, and the practicable upper limit value is 700% in consideration of process
passability in the post-processing process. The breaking strength and degree of extension
can be adjusted by controlling the conditions in the manufacturing process according
to the intended application. When the bulky yarn of the present invention is used
in general clothing applications such as underwear and outerwear or sleepwear such
as bedclothes and pillows, the breaking strength is preferably 0.5 to 4.0 cN/dtex.
It is particularly preferable that the breaking strength be 1.0 to 6.0 cN/dtex in
sports clothing applications where the use situation is relatively harsh.
[0054] The bulky yarn of the present invention has stretchability. As a result of intensive
investigation to exhibit stretchability not achieved in the past, the present inventors
have found that by adjusting the properties of the core yarn, comfortable stretchability
is exhibited in the processed bulky textured yarn. As a requirement for exhibiting
this stretchability, though stretchability is exhibited in principle when the core
yarn is excellent in extension recovery, to achieve the object of the present invention,
it is suitable to generate the interlacing point between the core yarn and the sheath
yarn to such an extent that a loop is formed, which is an important requirement also
from the viewpoint of prevention of flattening of the bulky textured yarn. As a result
of intensive investigations from such a viewpoint, it was found that the fiber used
for the core yarn of the present invention is preferably a side-by-side or eccentric
core-in-sheath conjugate fiber, from the viewpoint that the opening properties of
the textured yarn in the processing described later are good and the necessary interlacing
points are formed.
[0055] As illustrated in Fig. 4 (4-1), the side-by-side conjugate fiber herein refers to
a fiber having a structure in which an A polymer (reference sign 7 in Fig. 4) and
a B polymer (reference sign 8 in Fig. 4) having different properties are bonded together
in the fiber cross section in the direction perpendicular to the fiber axis. As shown
in Fig. 4 (4-2), the eccentric core-in-sheath conjugate fiber refers to a fiber having
a structure in which the A polymer (reference sign 7 in Fig. 4 (4-2)) is arranged
on either the left or the right from the center of gravity and the B polymer (reference
sign 8 in Fig. 4 (4-2)) is arranged so as to cover the A polymer in the fiber cross
section perpendicular to the fiber axis.
[0056] Both of these fibers exhibit crimps according to the shrinkage difference between
the A polymer and the B polymer as well as the fiber diameter. In accordance with
the crimps, the stretchability of the present invention is exhibited. The crimps exhibited
by the conjugate fiber are generally on the order of micrometers, thereby fixing points
suitable for making loops self-stand are formed. It is suitable that in the original
yarn stage, the yarn have a relatively flat fiber form, and the yarn exhibit fine
crimps after processing for the durability of the bulky textured yarn and the traveling
property and the like during processing. Among the conjugate fibers, side-by-side
and eccentric core-in-sheath conjugate fibers of high viscosity polyethylene terephthalate/low
viscosity polyethylene terephthalate and polybutylene terephthalate/polyethylene terephthalate
are more preferable.
[0057] The bulky yarn of the present invention can have high extension characteristics at
low stress and exhibit anti-flattening properties, that is, high resilience utilizing
the found principle. In this case, it is preferable to use an elastic yarn as the
core yarn. Examples of the elastic yarn used for the core yarn include fibers containing
as a main component at least polytrimethylene terephthalate, a polybutylene terephthalate
copolymer and a thermoplastic polyurethane. In particular, from the viewpoint that
a soft touch feeling can be obtained by minimizing the tightening feeling for wearing
comfort in the case where a produce made from the yarn is worn in an extended state,
the elastic yarn is more preferably a fiber made of a thermoplastic polyurethane or,
considering handling properties, a polyester elastomer.
[0058] The characteristic of excellent extension characteristics at low stress can be evaluated
by stress at 10% modulus. That is, the 10% modulus indicates the rigidity when 10%
strain is applied to the fiber. When the value of the 10% modulus is lower, the fiber
can be deformed flexibly from the beginning. Therefore, in the bulky yarn of the present
invention, it is preferable that the 10% modulus be less than 1.5 cN/dtex as an index
for flexible deformation.
[0059] The term "10% modulus" as used herein refers to the stress when 10% extension strain
is applied, and is obtained by obtaining a stress-strain curve of a bulky yarn under
conditions shown in JIS L 1013 (1999) and dividing the load at the time of applying
10% strain by the fineness of the core yarn. This operation is performed on 5 samples
for each level, and a simple average value of the obtained results is obtained, and
rounded off to the first decimal to obtain the 10% modulus.
[0060] When the 10% modulus is high, the bulky yarn is not flexibly extended and deformed.
When the stress is less than 1.5 cN/dtex, the bulky yarn can be flexibly deformed
from the beginning of deformation. Therefore, when the fiber is applied to clothes
or the like, discomfort such as a feeling of oppression and a taut feeling on wear
comfort is reduced, and particularly when the fiber is applied to a part of the elbow
or the knee where a taut feeling is felt, very comfortable wear comfort is provided.
From the viewpoint of extensibility at low stress, it is suitable that the stress
required for extension deformation be low, and the 10% modulus is more preferably
less than 1.0 cN/dtex, further preferably less than 0.5 cN/dtex. The substantial lower
limit of the 10% modulus in the present invention is 0.1 cN/dtex.
[0061] In view of the object of the present invention, for example, when a jacket or the
like is designed, it is suitable to change the characteristics of the bulky yarn depending
on the site. In conventional techniques, the characteristics are changed merely by
adjusting the filling amount or the like. In this case, it is impossible to achieve
a packing property and a fitting property for enhancing the heat retention effect
while suppressing an unpleasant feeling of oppression caused by stress of extension
of the material especially at around the neck, cuffs and elbow. Meanwhile, in the
bulky yarn of the present invention, such characteristics can be adjusted by appropriately
changing the characteristics of the core yarn. It is possible to manufacture a bulky
yarn having extensibility suitable for each site by the manufacturing method described
later, and it is possible to sew comfortable products by utilizing the bulky yarn.
[0062] To enhance the extensibility at low stress, it is preferable that the fiber extension
ratio at load application be not less than 1.1, and the fiber length restoration rate
be 80 to 100%.
[0063] The fiber extension ratio at load application herein can be obtained by applying
a predetermined load to a sample taken at a specific length to extend the sample,
and calculating the change in the sample length before and after load application
extension. That is, 5 m of a bulky yarn is taken using a 1 m/circumference skein,
and the taken yarn is hung with one end of the skein hooked. Then, an initial load
per sample fineness of 0.03 cN/dtex is applied to the sample to measure the original
length (L0) before load application extension. Subsequently, the initial load is removed,
and the sample is left to stand for 1 minute with an extension load per sample fineness
of 1.5 cN/dtex being applied. Then, the sample length (L1) at load application extension
is measured, and the fiber extension ratio at load application is calculated using
the formula below. The same operation is performed on 5 samples for each level, and
a simple average value of the obtained results is obtained, and rounded off to the
first decimal place to obtain the ratio.
[L0: original length before load application extension (cm), L1: length at load application
extension (cm)]
[0064] Subsequent to the measurement of the extension ratio at load application, the extension
load is removed, and the sample length (L2) after the load application extension with
the above-mentioned initial load being applied is measured. Then, the fiber length
restoration rate after load application extension is calculated by the following formula.
The same operation is performed on 5 samples for each level, and a simple average
value of the obtained results is obtained, and rounded off to the nearest whole number
to obtain the fiber length restoration rate.
[L0: original length before load application extension (cm), L1: length at load application
extension (cm), L2: length after load application extension (cm)]
[0065] When the extension ratio at load application is not less than 1.1, the textured yarn
can be highly extended. When the fiber length restoration rate is not less than 80%,
the textured yarn has excellent shape recoverability after stretching, that is, anti-flattening
properties. That is, the higher the extension ratio at load application and the fiber
length restoration rate, the closer the deformation of the bulky yarn to the rubber
elastic deformation. Thus, a bulky yarn having a high extension ratio at load application
and a high fiber length restoration rate is suitable for applications in which relatively
high extension deformation and repeated extension recovery are repeated. Therefore,
for example, when a textured yarn having the characteristics in the above-mentioned
range is used in clothing, the yarn is suitably used in a site where repeated extension
recovery is applied, such as the elbow or the knee. In such a case, stress due to
tension and the like is not felt and the deformation almost completely recovers, and
thus the shape of the clothing is not lost. Furthermore, when the yarn is combined
with an outer fabric having stretchability, clothing fitted to the body can be tailored.
In this case, a high degree of heat retaining properties due to adherence can be secured,
and at the same time, the clothing flexibly deforms in conformity with the individual's
body constitution, so that various people can wear the clothing of one size and sewing
pattern comfortably.
[0066] When the bulky yarn of the present invention is used for applications in which the
tightening feeling needs to be minimized and a soft touch feeling is appealed, including
general clothing applications such as underwear and outerwear, nightclothes, clothing
for the injured, and clothing for pregnant women, the extension ratio at load application
is more preferably not less than 1.5, further preferably not less than 2.0. When the
yarn is used as a material excellent in shape recoverability such as a material that
recovers to its original form even after being compactly stored, the fiber length
restoration rate after load application is more preferably not less than 90%, further
preferably not less than 95%.
[0067] In these extension characteristics, the upper limit of the extension is the extension
at which the sheath yarn of the bulky yarn is fully extended. Thus, the substantial
upper limit of the extension ratio at load application in the present invention is
20.0.
[0068] The fiber used in the present invention is preferably a hollow cross-section fiber.
The hollow cross-section fiber is suitable from the viewpoint that, as an advantage
of the manufacturing method described later, the three-dimensional crimp size on the
millimeter order, which is a preferable form of the sheath yarn, can be controlled
relatively freely from a large size to a small size, as well as the viewpoint of the
self standing of the loop. That is, in the bulky yarn of the present invention, the
self standing of the loop formed by the sheath yarn is responsible for the bulkiness.
Self standing of the sheath yarn is achieved by the interlacing point with the core
yarn and the rigidity of the sheath yarn. However, considering the anti-flattening
properties, it is preferable that the sheath yarn itself be also lightweight. Therefore,
specifically, it is suitable that the density (weight per unit volume) of the sheath
yarn be lower, and a fiber having a hollow cross section is preferably used. From
the viewpoint of the lightweight properties of the sheath yarn, hollow cross-section
fibers having a hollow rate of not less than 20% are more preferable. The hollow rate
herein is measured in the following manner. A hollow cross-section fiber is cut and
then the cut surface is photographed two-dimensionally with an electron microscope
(SEM) at a magnification enabling observation of 10 or more fibers. Ten fibers randomly
selected from the photographed image are picked up, and the area of the fibers and
the hollow portions is measured using image processing software, and the hollow rate
is obtained as the area rate. All of the above-mentioned values were measured for
10 images and the average value of 10 images was taken as the hollow rate of the hollow
cross-section fiber of the present invention. To easily obtain the hollow rate, the
side surface of the fiber is observed with a microscope or the like, and the fiber
diameter in terms of round cross section is measured from the image. It is also possible
to obtain the hollow rate by calculating the rate of the actually measured fineness
(actually measured weight) in the fineness in terms of a solid fiber (converted weight)
from the fiber diameter.
[0069] From the viewpoint of lightweight and heat retaining properties, which is an object
of the present invention, the bulky yarn preferably has a larger air layer, and the
hollow rate is particularly preferably not less than 30%. Within the above-mentioned
range, improved lightweight properties can be achieved when a bundle of the textured
yarn is held, and the textured yarn is excellent in heat retaining properties because
the textured yarn has an air layer having a lower thermal conductivity. The substantial
upper limit of the hollow rate in the present invention is 50%.
[0070] The sheath yarn of the bulky yarn of the present invention preferably has a density
of less than 1.00 g/cm
3. The density of the sheath yarn herein refers to the weight per unit volume of the
sheath yarn, which is measured using a density gradient tube by the method according
to JIS L 1013: 2010. When the density of the sheath yarn falls within the above-mentioned
range, a product having lightweight properties and high comfortability in use is provided
when the yarn is used as wadding for clothing and bedding. From the viewpoint of increasing
the lightweight properties of the bulky yarn, the density of the sheath yarn is more
preferably not greater than 0.95 g/cm
3, still more preferably not greater than 0.90 g/cm
3.
[0071] To provide an unprecedented bulky yarn having lightweight properties, mechanical
properties, and a repulsion feeling, the fiber used for the sheath yarn is preferably
an islands-in-sea conjugate fiber having a hollow cross section. The islands-in-sea
conjugate fiber herein refers to a conjugate fiber having a cross-sectional structure
in which an island component made of a certain polymer is scattered in a sea component
made of another polymer. An example of the islands-in-sea conjugate fiber having this
hollow cross section is a donut-shaped islands-in-sea conjugate fiber having a hollow
portion (9) in the center of the fiber cross section and an island component (10)
scattered in a sea component (11), as shown in Fig. 5.
[0072] As described above, due to the air contained in the hollow portion at the center
of the cross section of the fiber, in addition to the lightweight properties, the
heat insulating effect is obtained by the air layer contained in the hollow portion,
thereby heat retaining properties are obtained. Furthermore, in the sea-island structure
around the hollow portion, the island component scattered in the sea component disperses
the impact such as compression and bending on the bulky yarn. Thus, the sea-island
structure reinforces while maintains the flexibility of the sheath yarn, greatly suppresses
the flattening, which sometimes causes a problem in a fiber having a high hollow rate,
and makes the bulky yarn highly resilient.
[0073] Combinations of polymers used for the island component and the sea component of the
islands-in-sea conjugate fiber can be appropriately selected and used from the above-mentioned
polymer group. However, among them, it is preferable that the island component be
a polyolefin, and the sea component be a polyester from the viewpoint of promoting
the weight reduction of the bulky yarn and achieving physical properties that provide
sufficient durability for the use as a fiber product. Polyolefins have low density,
and thus when they are used for an island component, islands-in-sea conjugate fibers
are lightweight. When a polyester is used as a sea component, physical properties
such as the degree of strength and extension of the islands-in-sea conjugate fiber
become suitable for a fiber product, and the sea component which is a matrix of the
islands-in-sea conjugate fiber has crystallinity. Therefore, the yarn becomes resistant
to deterioration and flattening in processing and use. In this case, the conjugate
ratio of the island/sea is preferably 50/50 to 10/90 from the viewpoint of providing
the islands-in-sea conjugate fiber with sufficient characteristics for the use as
a fiber product. The conjugate ratio of the island/sea is more preferably 50/50 to
20/80, further preferably 50/50 to 30/70 from the viewpoint of further increasing
the proportion of the low density polyolefin of the island component to improve the
lightweight properties of the islands-in-sea conjugate fiber.
[0074] The bulky yarn of the present invention can be used in various fiber structures and
various fiber products such as fiber winding packages, tows, cut fibers, batting,
fiber balls, cords, piles, and woven and nonwoven fabrics. Herein, the fiber products
can be used in livingware applications such as general clothing, sports clothing,
clothing materials, interior products such as carpets, sofas and curtains, vehicle
interior decorations such as car seats, cosmetics, cosmetic masks, wiping cloths,
health supplies, as well as environmental/industrial material application such as
filters and hazardous substance removal products. In particular, the bulky yarn of
the present invention is suitably utilized as a filling material because of the bulkiness
and the entanglement suppression effect. In this case, the bulky yarn is preferably
used as yarn bundles having several to several tens of fibers or a sheet-shaped material
such as a nonwoven fabric because the yarn is filled into an outer fabric. Particularly
when the yarn is made into a sheet, the yarn is easily filled into an outer fabric,
and it is easy to adjust the filling amount according to the application. Therefore,
a thin, lightweight and heat-retentive material is provided, and moreover, there is
no worry that the material gets out of the outer fabric, and sewing is unnecessary.
Thus, there is no restriction on the form of the fiber product, and a complicated
design and the like become possible.
[0075] An example of the method for manufacturing the bulky yarn of the present invention
will be described in detail below.
[0076] As the core yarn and the sheath yarn used in the present invention, a synthetic fiber
obtained by fiberizing a thermoplastic polymer by a melt spinning method may be used.
[0077] The spinning temperature at the time of spinning the synthetic fiber used in the
present invention is a temperature at which the polymer used exhibits fluidity. The
temperature at which the fluidity is exhibited varies depending on the molecular weight,
but the melting point of the polymer serves as a rough indication, and the spinning
temperature may be set at a temperature not greater than the melting point + 60°C.
A temperature in the above-mentioned range is preferable because the polymer does
not undergo thermal decomposition or the like in the spinning head or the spinning
pack, and the molecular weight reduction is suppressed. A range of discharge amount
allowing stable discharge is 0.1 g/min/hole to 20.0 g/min/hole per discharge hole.
In this case, it is preferable to consider the pressure loss in the discharge hole
that can ensure discharge stability. The pressure loss herein is preferably determined
in the range of 0.1 MPa to 40 MPa as an index based on the relationship among the
melt viscosity of the polymer, the discharge hole diameter and the discharge hole
length.
[0078] The molten polymer discharged in this way is cooled and solidified, and is taken
up by a roller whose peripheral speed is regulated after application of an oil agent
to become a synthetic fiber. This take-up speed may be determined from the discharge
amount and the intended fiber diameter, but in order to stably produce a synthetic
fiber, it is preferable to set the take-up speed in the range of 100 to 7000 m/min.
From the viewpoint of improving the orientation of the synthetic fiber and improving
the mechanical properties, the synthetic fiber may be drawn after being wound up,
or may be drawn without being wound up. As the drawing conditions, for example, in
a drawing machine having one or more pairs of rollers, as long as a fiber made of
a polymer generally showing synthetic fibers capable of melt spinning is used, the
fiber is naturally stretched in the fiber axis direction, thermally set, and wound
up due to the peripheral speed ratio between the first roller set to a temperature
not less than the glass transition temperature and not greater than the melting point
and the second roller at a temperature equivalent to the crystallization temperature.
In the case of a polymer showing no glass transition, the dynamic viscoelasticity
measurement (tan δ) of the conjugate fiber is carried out, and a temperature not less
than the temperature of the peak on the high temperature side of the obtained tan
δ is selected as the preheating temperature. From the viewpoint of increasing the
draw ratio and improving the mechanical properties, it is also a suitable means to
apply this drawing step in multiple stages.
[0079] The cross-sectional shape of the synthetic fiber of the present invention is not
particularly limited, and by changing the shape of the discharge hole in the spinneret,
it is possible to obtain a general round cross section, a triangular cross section,
a Y shape, an octagonal shape, a flat shape, and amorphous shapes such as a diverse
shape and a hollow shape. The fiber may be made of a single polymer, or may be a conjugate
fiber made of two or more kinds of polymers. However, from the viewpoint of exhibiting
the three-dimensional crimp of the sheath yarn, which is an important requirement
of the present invention, it is preferable to use a hollow cross-section fiber or
a side-by-side conjugate fiber in which two types of polymers are bonded together.
That is, these fibers exhibit a three-dimensional crimp due to a structural difference
in the cross-sectional direction by the heat treatment after yarn making and yarn
processing. Therefore, although it is a so-called straight fiber at the time of fluid
processing to be described later, a three-dimensional crimp is exhibited by the application
of heat treatment after the loop forming step with a sheath yarn. If the fibers are
straight at the time of bulky processing, the yarns easily stably travel without causing
clogging of a nozzle or the like with the yarn. Furthermore, also in forming the loop
of the present invention, the core yarn and the sheath yarn are efficiently swirled,
and the loop is formed very uniformly in the fiber axis direction of the textured
yarn. By subjecting the textured yarn with loops formed in the outer layer to heat
treatment at the crystallization temperature of the polymer as an index, the sheath
yarn exhibits a three-dimensional crimp and the bulky yarn of the present invention
is provided.
[0080] The three-dimensional crimp of the sheath yarn provides good bulkiness both in the
circumferential direction and in the cross-sectional direction of the textured yarn,
and is suitably appropriately controlled depending on the required characteristics.
From the viewpoint of control of crimp exhibition after the heat treatment, the fiber
used in the present invention is more preferably a hollow cross-section fiber. The
hollow cross-section fiber has an air layer having a low thermal conductivity at the
center of the fiber. Therefore, for example, a fiber material is discharged from a
spinneret capable of forming a hollow cross section, and then one side of the material
is forcibly cooled with excessive cooling air or the like, or one side of the material
is excessively heat-treated with a heating roller or the like at the time of drawing,
thereby the difference in structure is generated in the cross-sectional direction
of the fiber. In the case of a hollow cross-section fiber, yarn making can be performed
by a single spinning machine, and in addition, the size of the three-dimensional crimp
can be relatively freely controlled from a large size to a small size by the above-described
operation. Therefore, the hollow cross-section fiber is suitably used in the present
invention, and from the viewpoint of crimp control by the above-described operation,
a hollow cross-section fiber having a hollow rate of not less than 20% is more preferable,
and a hollow cross-section fiber having a hollow rate of not less than 30% is particularly
preferable.
[0081] In the bulky yarn of the present invention, as a first step, prescribed amounts of
core yarn (reference sign 20 in Fig. 6) and sheath yarn (reference sign 21 in Fig.
6) that are described above are supplied by supply rollers (reference sign 19 in Fig.
6) having a nip roller or the like, and the core yarn and the sheath yarn are sucked
by means of a suction nozzle (reference sign 12 in Fig. 6) capable of injecting compressed
air.
[0082] In the suction nozzle (reference sign 12 in Fig. 6), the flow rate of the compressed
air injected from the nozzle may be a flow rate at which the yarn inserted into the
nozzle from the supply rollers has the necessary minimum tension and stably travels
without yarn swaying or the like between the supply rollers and the nozzle and within
the nozzle. Although the optimum amount of the flow rate of the compressed air changes
depending on the hole diameter of the suction nozzle used, the airflow rate in the
nozzle is not less than 100 m/s as an index of a range in which yarn tension can be
provided and a loop to be described later can be smoothly formed. An approximate upper
limit of the airflow rate is not greater than 700 m/s. Within this range, the traveling
yarn will stably travel within the nozzle without yarn swaying or the like caused
by excessively injected compressed air.
[0083] Further, from the viewpoint of preventing intermingling and opening in the nozzle
and the viewpoint of uniformly forming loops by a sheath yarn with high productivity,
it is preferable that a jet angle (reference sign 22 in Fig. 7) of the compressed
air be an angle of a propulsive jet flow that is jetted at an angle less than 60°
with respect to the traveling yarn. Naturally, it is not impossible to manufacture
the bulky yarn of the present invention by processing with a vertical jet flow which
injects a fluid at an angle of 90° to the traveling yarn. However, processing with
a propulsive jet flow is preferable from the viewpoint of opening the traveling yarn
by jet flow from the vertical direction and suppressing entanglement of single yarns
in a narrow space inside the nozzle. Due to the propulsive jet flow processing, the
formation of arch-shaped small loops which are easily formed at a short period in
the case of the vertical jet flow can also be suppressed.
[0084] To form the loops formed by sheath yarns required for the bulky yarn of the present
invention, it is suitable that intermingling or opening in the suction nozzle do not
occur. From the viewpoint of making a multifilament composed of several to several
tens of yarns travel without opening the fibers in the nozzle, it is more preferable
that the jet angle of the compressed air be not greater than 45° with respect to the
traveling yarn. Furthermore, to form a loop outside the nozzle to be described later,
it is suitable that stability and propulsive force of the jet air stream immediately
after the nozzle be high. From this viewpoint, the jet angle is particularly preferably
not greater than 20° with respect to the traveling yarn.
[0085] Next, as a second step of the present invention, the yarn sucked by the suction nozzle
is swirled outside the nozzle to form a loop of the sheath yarn.
[0086] The yarn may be introduced into the suction nozzle in one feed or in two feeds, however,
to manufacture the bulky yarn of the present invention, it is suitable to perform
processing in two feeds. The term "two-feeds" as used herein means a method in which
two or more yarns are supplied into the nozzle at different feed rates (amounts) preliminarily
given by a supply roller or the like. In the method, utilizing a turning force by
an airflow described later, an excessively supplied yarn (sheath yarn) forms a bulky
structure in which a loop is formed in an outer layer. When utilizing this two feeds,
it is possible to manufacture a textured yarn having a loop using an interlace processing
nozzle or a Taslan processing nozzle that imparts intermingling, opening and entangling
effects to the traveling yarn inside the nozzle. However, the yarns processed with
these processing nozzles have loops formed at a short period, and in addition, reduced
size. Therefore, to manufacture the bulky yarn that satisfies the object of the present
invention, many parameters have to be finely controlled, and this is very difficult.
There is a possibility that the bulkiness of the textured yarn will be different by
the spindle when multi-spindle spinning is carried out, and thus, it is suitable to
use a method that utilizes airflow control outside the nozzle as described later from
the viewpoint of stability of quality. Regarding this point, the present inventors
got an idea of a concept that a loop can be formed by turning two yarns supplied at
a position distant from the nozzle without giving any intermingling or opening treatment
in the nozzle. As a result of intensive studies from the viewpoint of controlling
the airflow injected from the nozzle, the present inventors found a specific phenomenon
that the sheath yarn turns while opening when the ratio of the airflow rate to the
yarn velocity (airflow rate/yarn velocity) is from 100 to 3000.
[0087] The airflow rate referred to herein is the speed of the airflow injected from the
downstream of the suction nozzle accompanying the traveling yarn, and can be controlled
by the discharge diameter of the nozzle and the flow rate of the compressed air. The
yarn speed can be controlled by the circulating speed of the roller which picks up
the textured yarn after the fluid processing nozzle. The turning force of the traveling
yarn increases and decreases depending on the speed ratio of the airflow to the yarn.
Therefore, in the case of strengthening the interlacing point of the intended bulky
yarn, the speed ratio should be approximated to 3000, and conversely in the case of
making the interlacing point loose, the speed ratio should be approximated to 100.
For the speed ratio, for example, it is also possible to change the interlacing degree
of the interlacing point by changing the flow rate of the compressed air intermittently
or by changing the speed of the take-up roller. Meanwhile, when the bulky yarn of
the present invention is used for applications in which repeated compression recovery
deformation such as in filling is imparted, it is preferable to set the airflow rate/yarn
speed in the range of 200 to 2000. In particular, in the case of manufacturing a textured
yarn used for clothing such as a jacket to which deformation is frequently applied,
from the viewpoint of imparting moderate binding and flexibility, it is particularly
preferable to set the airflow rate/yarn speed in the range of 400 to 1500.
[0088] A turning point (reference sign 13 in Fig. 6), which is the base point at which the
turning force is generated, is a point at which the traveling yarn is separated from
the accompanying airflow. Specifically, the turning point is made by just changing
the yarn path with a bar guide or the like. The sheath yarn turns around the core
yarn to form a loop when the traveling yarn is taken up at a specified speed by a
take-up roller (reference sign 15 in Fig. 6) in the traveling direction of the traveling
yarn. From the viewpoint of loosening the sheath yarn by the vibration of the sheath
yarn based on the space for turning and the diffusion of the airflow injected from
the nozzle, it is suitable that the turning point of the traveling yarn be located
away from the nozzle discharge port. However, the distance between the nozzle and
the turning point suitable for manufacturing the bulky yarn of the present invention
varies depending on the rate of the ejected air, and it is preferable that the turning
point (reference sign 13 in Fig. 6) be present during a period in which the ejected
airflow travels for 1.0 × 10
-5 seconds to 1.0 × 10
-3 seconds. To form an interlacing point between the core yarn and the sheath yarn at
an appropriate period keeping the balance with the diffusion of the airflow, the distance
between the nozzle and the turning point is preferably a distance at which the ejected
airflow travels for 2.0 × 10
-5 seconds to 5.0 × 10
-4 seconds.
[0089] By adjusting the turning point, it is also possible to control the period of the
interlacing points of the bulky yarn of the present invention. The interlacing points
play a role of supporting the self standing of the loop formed by the sheath yarn,
which is a characteristic of the present invention, and are suitably present at a
certain period. From this viewpoint, it is preferable to adjust the turning point
so that 1/mm to 30/mm of the interlacing points of the core yarn and the sheath yarn
are present in the bulky yarn. Within the above-mentioned range, it is preferable
because even after the three-dimensional crimp of the sheath yarn is exhibited, the
loops are present at a moderate interval. Further from this viewpoint, it is more
preferable to adjust the turning point so that 5/mm to 15/mm of interlacing points
are present.
[0090] A textured yarn (reference sign 14 in Fig. 6) having the loops formed by the sheath
yarn is preferably subjected to heat treatment to fix the shape and exhibit the three-dimensional
crimp after once wound up or following bulky processing. In Fig. 6, a processing step
of performing heat treatment subsequently to the loop forming step is exemplified.
[0091] The heat treatment (16 in Fig. 6) is performed by heating a textured yarn with a
heater or the like, and the processing temperature is the crystallization temperature
of the polymer used ± 30°C as an index. In the case of the treatment in this temperature
range, since the treatment temperature is far from the melting point of the polymer,
a fused and cured part between the sheath yarns or the core yarns is not generated.
Thus, there is no foreign body sensation, and the good touch feeling of the bulky
yarn of the present invention is not impaired. A general contact type or non-contact
type heater can be employed as a heater used in the heat treatment step, but a non-contact
type heater is suitably employed from the viewpoint of bulkiness before heat treatment
and suppression of deterioration of the sheath yarn. The non-contact type heater herein
is an air heating type heater such as a slit type heater or a tube type heater, a
steam heater for heating with high temperature steam, and a halogen heater, a carbon
heater, and a microwave heater in which radiant heating is used.
[0092] From the viewpoint of heating efficiency, a heater utilizing radiant heating is preferable.
The index of the heating time is, for example, the time when the fiber structure of
the fibers that constitute the textured yarn is fixed after the crystallization, or
the shape of the textured yarn is fixed and crimp exhibition of the sheath yarn is
completed, and is suitably adjusted according to the intended characteristics at the
treatment temperature and the treatment time. The speed of the textured yarn that
has undergone the heat treatment step is restricted by a delivery roller (reference
sign 17 in Fig. 6) and wound with a winder or the like equipped with a tension control
function (reference sign 18 in Fig. 6). Regarding the winding shape, there is no particular
limitation and it is possible to employ so-called cheese winding or bobbin winding.
In consideration of processing into the final product, it is also possible to preliminarily
consolidate a plurality of pieces to make a tow, or to form the textured yarn into
a sheet as it is.
[0093] It is preferable that a silicone oil agent be uniformly attached to the bulky yarn
of the present invention before and after the heat treatment step. It is advisable
to form a silicone film on the sheath yarn and the core yarn by moderately crosslinking
the silicone to be attached by heat treatment or the like. Examples of the silicone
oil agent referred to herein include dimethylpolysiloxane, hydrodienemethylpolysiloxane,
aminopolysiloxane, and epoxypolysiloxane, and these may be used alone or in combination.
From the viewpoint of uniformly forming a film on the bulky yarn, a dispersant, a
viscosity modifier, a crosslinking accelerator, an antioxidant, a fire retardant,
and an antistatic agent can be incorporated within a range not impairing the purpose
of silicone attachment. Although the silicone oil agent may be straight or used as
an aqueous emulsion, it is suitable to use the silicone oil agent as an aqueous emulsion
from the viewpoint of uniform attachment of the oil agent. It is suitable that the
silicone oil agent be treated so that 0.1 to 5.0 wt% of the silicone oil agent can
be attached to the bulky yarn in mass ratio by using an oil agent guide, an oiling
roller, or a spray. After that, it is preferable to dry the silicone oil agent at
an arbitrary temperature and an arbitrary time to cause a crosslinking reaction. The
silicone oil agent can be attached in a plurality of separate portions, and it is
also suitable to laminate a strong silicone film by separately attaching the same
kind of silicone or different kinds of silicone in separate portions. By forming the
silicone film on the bulky yarn by the above-mentioned treatment, the slipperiness
and the touch feeling of the bulky yarn are improved, and the effect of the present
invention can be further enhanced.
EXAMPLES
[0094] Hereinafter, the bulky yarn of the present invention will be specifically described
with reference to examples.
[0095] For the examples and comparative examples, the following evaluations were made.
A. Fineness
[0096] Fineness was calculated by measuring the weight of 100 m of a fiber and multiplying
the weight by 100. This calculation was repeated 10 times, and the value obtained
by rounding off the simple average of the 10 calculation results to the first decimal
place was taken as the fineness of the fiber. The single yarn fineness was calculated
by dividing the above-mentioned fineness by the number of filaments that constitute
the fiber. Also in this case, the value obtained by rounding off the value to the
first decimal place was taken as the single yarn fineness.
B. Mechanical properties (strength, elastic modulus, and 10% modulus) of fiber
[0097] Using a tensile tester Tensilon model UCT-100 manufactured by Orientec Co., Ltd.,
a stress-strain curve of a fiber was obtained under conditions of a sample length
of 20 cm and a tensile speed of 100%/min. The load at breakage was read and the load
was divided by the initial fineness to calculate the strength. The elastic modulus
was determined from the slope of the initial rising portion of the stress-strain curve
by linear approximation. The 10% modulus was calculated by reading a load of 10% strain
and dividing the value by the initial fineness. All the values were obtained by performing
the same operation on 5 samples for each level, obtaining a simple average value of
the obtained results, and rounding off the simple average value to the nearest whole
number for the strength and the elastic modulus, and to the first decimal place for
the 10% modulus.
C. Extension recovery rate of fiber at 10% extension
[0098] Using a tensile tester Tensilon model UCT-100 manufactured by Orientec Co., Ltd.,
a fiber was extended by 10% under conditions of a sample length of 20 cm and a tensile
speed of 100%/min, then left to stand for 1 minute, and recovered to the original
sample length at the same speed. This operation was repeated 10 times, the stress-strain
curve at this time was recorded, and the length (S0) at 10% extension and the length
(S1) at which the stress reached 0 were obtained to obtain the extension recovery
rate by the following formula. The same operation was performed on 5 samples for each
level, and a simple average value of the obtained results was obtained, and rounded
off to the nearest whole number to obtain the extension recovery rate.
[S0: length at 10% extension, S1: length at which the stress reached 0]
D. Fiber extension ratio at load application and fiber length restoration rate
[0099] On a 1 m/circumference skein, 5 m of a fiber was taken, and the taken fiber was hung
with one end of the skein hooked. Then, an initial load of 0.03 cN/dtex was hung from
the skein to measure the original length (L0). Subsequently, the initial load was
removed, a load of 1.5 cN/dtex was hung, and the sample was left to stand for 1 minute.
Then, the sample length (L1) at load application extension was measured, and the fiber
extension ratio at load application was calculated using the formula below. The extension
ratio at load application was obtained by performing the same operation on 5 samples
for each level, obtaining a simple average value of the obtained results, and rounding
off the simple average value to the first decimal place.
[L0: original length before load application extension (cm), L1: length at load application
extension (cm)]
[0100] Following the measurement of the extension ratio at load application, the applied
extension load was removed, then, a load of 0.03 cN/dtex same as the initial load
was hung from the skein, and the sample length (L2) after the load application was
measured to obtain the fiber length restoration rate by the following formula. Also
in this case, the fiber length restoration rate was obtained by performing the same
operation on 5 samples for each level, obtaining a simple average value of the obtained
results, and rounding off the simple average value to the nearest whole number.
[L0: original length before load application extension (cm), L1: length at load application
extension (cm), L2: length after load application extension (cm)]
E. Density
[0101] The density of the fiber was measured according to JIS L 1013: 2010 using a density
gradient tube. After the sample reached the equilibrium position in the liquid and
stopped, the sedimentation depth of the sample was read from the scale of the density
gradient tube to 1 mm, and the value was compared with the correction curve to obtain
the density. The density was obtained by performing this operation twice for each
level, obtaining a simple average value of the obtained results, and rounding off
the simple average value to the second decimal place.
F. Evaluation of loop (size, number, and breakage)
[0102] A load of 0.01 cN/dtex was applied so that slack does not occur in the textured yarn,
and a fixed length of the textured yarn was placed on a pair of yarn path guides as
shown in Fig. 2. The side of the placed textured yarn was photographed at a magnification
enabling observation of the entire loop with Microscope VHX-2000 manufactured by Keyence
Corporation. The distances (reference sign 5 in Fig. 2) from the surface of the yarn
to the tip of the loop were measured using image processing software (WINROOF) at
10 randomly selected positions in the obtained image. This procedure was performed
for a total of 10 images, and a total of 100 points were measured in units of millimeters
up to the first decimal place. An average value of these numerical values was calculated,
and a value obtained by rounding off the value to the first decimal place was taken
as the loop size (protrusion) in the present invention.
[0103] For the same 10 images, the tips of the loops and the breaking points of the sheath
yarn per unit distance were counted, and the number of loops and breaking points per
millimeter were calculated. The same operation was performed for the 10 images, and
the value obtained by rounding off the average value to the nearest whole number was
taken as the number of loops. Regarding the breaking points of the loops, the counted
breaking points of the loops were averaged and rounded off to the first decimal place
to obtain the breaking points of the loops. A sample having less than 0.2 breaking
points/mm was regarded as a sample in which the loops of the present invention are
continuously present and evaluated as a sample having no breaking points (evaluation:
A), and a sample having not less than 0.2 breaking points/mm was evaluated as a sample
having breakages (evaluation: C).
G. Crimp form evaluation (three-dimensional crimp and curvature radius)
[0104] At each of 10 points randomly selected from the textured yarn, 10 or more single
yarns were sampled, and each single yarn was observed with Microscope VHX-2000 manufactured
by Keyence Corporation at a magnification enabling confirmation of the crimp form.
In the image, if the observed single yarn had a spirally swirling form, the yarn was
judged to have a three-dimensional crimped structure (evaluation: A), and if the single
yarn had a straight form, the yarn was judged not to have a crimped structure (evaluation:
C). From the same image, the radius of the perfect circle inscribed most frequently
at two or more points in the curve (reference sign 6 in Fig. 3) of crimped fibers
was determined using image processing software (WINROOF). A total of 100 single yarns
randomly extracted as described above were measured up to the second decimal place
in units of millimeters, and the value obtained by rounding off the simple average
to the first decimal place was defined as the curvature radius of the three-dimensional
crimped structure of the present invention.
H. Coefficient of static friction between fibers
[0105] The coefficient of static friction between fibers was measured by a radar type coefficient
of friction tester according to JIS L 1015 (2010). The coefficient of static friction
between fibers was herein determined by arranging the textured yarns in parallel in
a cylinder.
I. Unwinding properties (effect of suppressing fastener phenomenon)
[0106] A drum on which not less than 500 m of the textured yarn was wound was laid on a
creel, released in the direction of the cross section of the drum for 5 minutes at
a speed of 30 m/min, and the disarraying and tangling of the yarn due to the fastener
phenomenon were visually confirmed and evaluated in the following four levels.
S: Disarraying of the yarn is not seen and the yarn can be unwound well.
A: Though disarraying of the yarn is seen slightly, the yarn can be unwound without
problem.
B: Though disarraying of the yarn and slight tangling is seen, the yarn can be unwound.
C: Disarraying and tangling of the yarn occur and the yarn cannot be unwound.
J. Touch feeling
[0107] A drum on which not less than 500 m of the textured yarn was wound was laid on a
creel, and the yarn was unwound using a measuring machine in the direction of the
cross section of the drum to form a winding form, thereby obtaining a 10 m yarn skein.
The yarn skein was fixed at one position and a sample for texture evaluation was prepared.
The touch feeling when the sample was gripped was evaluated in the following four
levels.
S: The yarn has excellent bulkiness and flexibility, and an excellent texture without
any foreign body sensation.
A: The yarn has bulkiness, flexibility, and a good texture.
B: The yarn has bulkiness and a good texture to the extent that a foreign body sensation
is not felt.
C: The yarn has no bulkiness, and has a poor texture that gives a foreign body sensation.
K. Bulkiness evaluation
[0108] The textured yarn (20 g) was filled in a cylindrical container having an inner diameter
of 28.8 cm and a height of 50.0 cm, the height H (cm) of the space occupied by the
textured yarn when a load of 0.15 g/cm
2 was applied vertically to the filled textured yarn from above was measured, the bulkiness
(inch
3/20 g) was calculated from the following formula, and the integer value obtained by
rounding off the value to the nearest whole number was taken as the bulkiness of the
textured yarn.
[0109] The height of each textured yarn was measured by reading the height from the scale
with the zero point on the bottom of the cylindrical container in mm units.
Example 1
[0110] High viscosity polyethylene terephthalate (PET 1: IV = 0.8 dl/g) as A polymer and
low viscosity polyethylene terephthalate (PET 2: IV = 0.5 dl/g) as B polymer were
prepared, melted at 295°C, then weighed, flowed into a spinning pack equipped with
a composite spinneret, and discharged so as to give a side-by-side conjugate cross
section composed of A polymer and B polymer as exemplified in Fig. 4 (4-1) (conjugate
ratio: A polymer/B polymer = 50/50). Cooling air at 20°C was blown against the discharged
yarn at a flow rate of 20 m/min to cool and solidify the yarn, and after application
of a spinning oil agent, an undrawn yarn was wound up at a spinning speed of 1500
m/min. A conjugate fiber (single yarn fineness: 7.0 dtex) obtained by drawing the
wound undrawn yarn 3.0 times at a drawing speed of 800 m/min between rollers heated
at 90°C and 140°C was used as a core yarn.
[0111] Next, polyethylene terephthalate (PET3: IV = 0.6 dl/g) was melted at 290°C, weighed,
flowed into a spinning pack, and discharged from a hollow cross-sectional discharge
hole in which three slits (width of 0.1 mm, reference sign 23 in Fig. 8) as shown
in Fig. 8 were concentrically disposed to give a yarn with a hollow rate of 30%. Cooling
air at 20°C was blown from one side against the discharged yarn at a flow rate of
30 m/min to cool and solidify the yarn, and after application of a spinning oil agent,
an undrawn yarn was wound up at a spinning speed of 1500 m/min. Subsequently, a hollow
fiber (single yarn fineness: 6.5 dtex) obtained by drawing the wound undrawn yarn
3.0 times at a drawing speed of 800 m/min between rollers heated at 90°C and 140°C
was used as a sheath yarn.
[0112] In the process illustrated in Fig. 6, the core yarn and the sheath yarn were supplied
to the suction nozzle at supply roller speeds of 50 m/min and 1000 m/min. In the suction
nozzle, compressed air was injected at 20° against the traveling yarn at an airflow
rate of 400 m/s, and the core yarn and the sheath yarn were jetted out together with
the accompanying airflow from the nozzle without entangling. The yarn injected from
the nozzle was made to travel for 1.0 × 10
-4 seconds with the airflow, the yarn path was changed using a ceramic guide, and the
textured yarn having the loop formed by the sheath yarn was taken up by a roller of
50 m/min. The textured yarn was continuously guided to a tube heater via rollers and
heat-treated with heated air at 150°C for 10 seconds to set the form of the bulky
yarn and to cause crimps to appear in the core yarn and the sheath yarn. The bulky
yarn was wound on a drum at 52 m/min by a tension control type winder installed behind
the tube heater.
[0113] In Example 1, a bulky yarn having 22/mm loops formed by a sheath yarn protruding
by 38.0 mm on average from the surface was obtained. The protruding loops were excellent
in size and period uniformity. The sheath yarn of the textured yarn had a three-dimensional
crimped structure with a curvature radius of 5.7 mm on the millimeter order, and the
sheath yarn had continuously formed loops without any broken portions. (number of
broken portions: 0.0)
[0114] Subsequently, a silicone oil agent containing polysiloxane at a concentration of
8 wt% was uniformly sprayed to the textured yarn with a spray so that the final amount
of polysiloxane attached was 1 wt% with respect to the bulky yarn, and the resulting
product was heat-treated at a temperature of 165°C for 20 minutes to obtain the bulky
yarn of the present invention.
[0115] In the bulky yarn, the sheath yarn that had continuously formed loops had a three-dimensional
crimped structure, the coefficient of static friction between fibers was 0.1, the
textured yarn had no problem in the unwinding properties, and the yarn was successfully
smoothly unwound from the drum around which the yarn was wound without tangling or
the like (unwinding properties: S). The elastic modulus that represents rigidity was
73 cN/dtex, and the extension recovery rate was 83%. Thus, the yarn had comfortable
stretchability (texture: S). The results are shown in Table 1.
Example 2
[0116] Example 2 was carried out in accordance with Example 1 except that a PET 1/PET 2
side-by-side conjugate fiber with a single yarn fineness adjusted to 3.0 dtex by adjusting
the discharge amount was used as a core yarn using the combination of polymers used
for the core yarn of Example 1.
[0117] In Example 2, the number of loops was slightly increased by decreasing the single
yarn fineness of the core yarn. The yarn was easily deformed at the time of extension
deformation and had a more flexible texture than Example 1 did. The results are shown
in Table 1.
Examples 3 and 4
[0118] Example 3 was carried out all in accordance with Example 1 except that A polymer
was changed to polybutylene terephthalate (PBT: IV = 1.2 dl/g) and a PBT/PET 2 side-by-side
conjugate fiber collected by yarn making using a composite spinneret used in Example
1 at a spinning temperature of 290°C was used as the core yarn. A bulky yarn having
the PBT/PET 2 side-by-side conjugate fiber having a single yarn fineness adjusted
to 3.0 dtex by adjusting the discharge amount as a core yarn was sampled in the same
polymer combination as in Example 3 (Example 4) .
[0119] In Examples 3 and 4, the core yarn exhibited relatively fine crimps at the original
yarn stage, and the number of loops was decreased in the bulky textured yarn. As compared
with that of Example 1, the yarns had a low elastic modulus, were extremely flexible,
and extended and deformed at low stress. The extension recovery rate was largely improved,
and even when the yarn was deformed to a relatively high degree, the yarn was not
flattened. Thus, the yarn is a material suitable for use in a site that is largely
moved. The results are shown in Table 1.
[Table 1]
|
Example 1 |
Example 2 |
Example 3 |
Example 4 |
Core yarn |
A polymer |
- |
PET 1 |
PET 1 |
PBT |
PBT |
B polymer |
- |
PET 2 |
PET 2 |
PET 2 |
PET 2 |
A/B ratio |
- |
50/50 |
50/50 |
50/50 |
50/50 |
Cross-sectional shape |
|
Side-by-side Fig. 4 (4-1) |
Side-by-side Fig. 4 (4-1) |
Side-by-side Fig. 4 (4-1) |
Side-by-side Fig. 4 (4-1) |
Single yarn fineness |
dtex/F |
7.0 |
3.0 |
7.0 |
3.0 |
Sheath yarn |
Polymer type |
- |
PET 3 |
PET 3 |
PET 3 |
PET 3 |
Cross-sectional shape |
- |
Single hollow |
Single hollow |
Single hollow |
Single hollow |
Single yarn fineness |
dtex/F |
6.5 |
6.5 |
6.5 |
6.5 |
Density |
g/cm3 |
0.97 |
0.97 |
0.97 |
0.97 |
Fluid processing |
Feed rate |
Core yarn feed rate |
m/min |
50 |
50 |
50 |
50 |
Sheath yarn feed rate |
m/min |
1000 |
1000 |
1000 |
1000 |
Feed rate ratio |
- |
20 |
20 |
20 |
20 |
Fineness ratio |
Sheath/core |
- |
0.9 |
2.2 |
0.9 |
2.2 |
Nozzle |
Airflow rate |
m/s |
400 |
400 |
400 |
400 |
Airflow rate/yarn speed |
- |
480 |
480 |
480 |
480 |
Injection angle |
° |
20 |
20 |
20 |
20 |
Intermingling/opening within nozzle |
- |
Absent |
Absent |
Absent |
Absent |
Turning point (distance/airflow rate) |
s |
0.0001 |
0.0001 |
0.0001 |
0.0001 |
Bulky yarn |
Loop |
Size (protrusion) |
mm |
38.0 |
32.0 |
25.9 |
22.4 |
Number |
Number/mm |
22 |
28 |
7 |
8 |
Breakage (breaking point) |
- |
Absent (0.0) |
Absent (0.0) |
Absent (0.0) |
Absent (0.0) |
Three-dimensional crimp |
- |
Present |
Present |
Present |
Present |
Curvature radius |
mm |
5.7 |
5.7 |
5.7 |
5.7 |
Characteristic |
Strength |
cN/dtex |
3.5 |
3.0 |
4.0 |
3.5 |
Elastic modulus |
cN/dtex |
73 |
71 |
56 |
51 |
10% modulus |
cN/dtex |
1.5 |
1.5 |
1.4 |
1.4 |
Extension recovery rate |
% |
83 |
79 |
94 |
89 |
Fiber extension ratio |
- |
1.2 |
1.1 |
1.3 |
1.2 |
Fiber length restoration rate |
% |
88 |
84 |
100 |
95 |
Coefficient of static friction between fibers |
- |
0.1 |
0.1 |
0.1 |
0.1 |
Fastener phenomenon |
- |
S |
S |
S |
S |
Touch feeling |
- |
S |
S |
S |
S |
Bulkiness |
inch3/20 g |
506 |
426 |
496 |
431 |
Comparative Example 1
[0120] The polyethylene terephthalate (PET3: IV = 0.6 dl/g) used in the sheath yarn in Example
1 was melted at 290°C, weighed, flowed into a spinning pack, and discharged from a
hollow cross-sectional discharge hole in which three slits (width of 0.1 mm, reference
sign 23 in Fig. 8) as exemplified in Fig. 8 were concentrically disposed to give a
yarn with a hollow rate of 30%. Cooling air at 20°C increased (100 m/min) compared
to that in Example 1 was blown from one side against the yarn to cool and solidify
the yarn, and after application of a spinning oil agent, an undrawn yarn was wound
up at a spinning speed of 1500 m/min. Subsequently, procedures were carried out all
in accordance with those in Example 1 except that a hollow fiber (single yarn fineness:
6.5 dtex) obtained by drawing the wound undrawn yarn 3.0 times at a drawing speed
of 800 m/min between rollers heated at 90°C and 140°C was used as the core yarn and
the sheath yarn.
[0121] In Comparative Example 1, the yarn had almost the same form properties as those of
Example 1, but the size of loops was small and the number of loops was reduced. Although
the yarn was relatively satisfactory in unwinding properties and texture, it had a
high elastic modulus and a decreased extension recovery rate. The results are shown
in Table 2.
Comparative Example 2
[0122] All of the procedures were carried out in accordance with Comparative Example 1 except
that a nozzle having an injection angle of compressed air changed to 90° was used
and no turning point by a ceramic guide was provided. However, in Comparative Example
2, at the compressed airflow rate similar to that of Comparative Example 1, the entanglement
between the core yarn and the sheath yarn was excessive and clogging of the nozzle
occurred. Therefore, the airflow rate was decreased to 200 m/s, which is half of that
of Comparative Example 1, to collect the textured yarn and evaluate properties thereof.
[0123] In the textured yarn of Comparative Example 2, since the loop size formed by the
sheath yarn was smaller than those of Example 1 and Comparative Example 1 before the
heat treatment, and the loops were formed in a very short period. Therefore, though
loops were formed in the yarn when the sheath yarn was heat-treated to be crimped,
the bulkiness was poor. Investigation of the details of the loop formed by the sheath
yarn proved that the loop size was not uniform and there were a relatively large number
of breaking points that were not confirmed before the heat treatment (breakage present:
0.5). The results are shown in Table 2.
Comparative Example 3
[0124] The textured yarn of Comparative Example 2 was abraded with a pair of rubber discs
to perform an untwisting treatment. Although bulkiness seemed to be apparently improved,
the breakage of the loop was further increased as compared with Comparative Example
2, entanglement of the sheath yarns was promoted, and a foreign body sensation was
felt when compressed. Also, in comparison with Comparative Example 2, tangling of
the yarn frequently occurred, and unwinding properties were deteriorated at the time
of unwinding. The results are shown in Table 2.
[Table 2]
|
Comparative Example 1 |
Comparative Example 2 |
Comparative Example 3 |
Core yarn |
A polymer |
- |
PET 3 |
PET 3 |
PET 3 |
B polymer |
- |
- |
- |
- |
A/B ratio |
- |
100/0 |
100/0 |
100/0 |
Cross-sectional shape |
|
Single hollow |
Single hollow |
Single hollow |
Single yarn fineness |
dtex/F |
6.5 |
6.5 |
6.5 |
Sheath yarn |
Polymer type |
- |
PET 3 |
PET 3 |
PET 3 |
Cross-sectional shape |
- |
Single hollow |
Single hollow |
Single hollow |
Single yarn fineness |
dtex/F |
6.5 |
6.5 |
6.5 |
Density |
g/cm3 |
0.97 |
0.97 |
0.97 |
Fluid processing |
Feed rate |
Core yarn feed rate |
m/min |
50 |
50 |
50 |
Sheath yarn feed rate |
m/min |
1000 |
1000 |
1000 |
Feed rate ratio |
- |
20 |
20 |
20 |
Fineness ratio |
Sheath/core |
- |
1.0 |
1.0 |
1.0 |
Nozzle |
Airflow rate |
m/s |
400 |
200 |
200 |
Airflow rate/yarn speed |
- |
480 |
240 |
240 |
Injection angle |
° |
20 |
90 |
90 |
Intermingling/opening within nozzle |
- |
Absent |
Present |
Present |
Turning point (distance/airflow rate) |
s |
0.0001 |
0 |
0 |
Bulky yarn |
Loop |
Size (protrusion) |
mm |
23.0 |
1.0 |
2.0 |
Number |
Number/mm |
13 |
73 |
54 |
Breakage (breaking point) |
- |
Absent (0.0) |
Present (0.5) |
Present (0.7) |
Three-dimensional crimp |
- |
Present |
Present |
Present |
Curvature radius |
mm |
5.0 |
4.2 |
4.0 |
Characteristic |
Strength |
cN/dtex |
4.2 |
2.3 |
1.9 |
Elastic modulus |
cN/dtex |
104 |
101 |
103 |
10% modulus |
cN/dtex |
2.9 |
2.9 |
2.9 |
Extension recovery rate |
% |
34 |
32 |
34 |
Fiber extension ratio |
- |
Breakage |
Breakage |
Breakage |
Fiber length restoration rate |
% |
|
|
|
Coefficient of static friction between fibers |
- |
0.3 |
0.5 |
0.6 |
Fastener phenomenon |
- |
S |
C |
C |
Touch feeling |
- |
A |
C |
C |
Bulkiness |
inch3/20 g |
450 |
14 |
27 |
Example 5
[0125] Example 5 was carried out all in accordance with Example 2 except that A polymer
was changed to polytrimethylene terephthalate (3GT: IV = 1.2 dl/g) and a 3GT/PET 2
side-by-side conjugate fiber collected by yarn making using a composite spinneret
used in Example 1 at a spinning temperature of 280°C was used as the core yarn (single
yarn fineness: 3.0 dtex).
[0126] In Example 5, the number of loops was reduced as compared with Example 1, and the
extension recovery rate was reduced due to extension of the crimp of the core yarn
at the time of processing. However, the stretchability was sufficiently secured, and
the yarn had a more flexible texture due to a decrease in elastic modulus. The results
are shown in Table 3.
Examples 6 and 7
[0127] Examples 6 and 7 were carried out all in accordance with Example 1 except that the
feed rate was changed to 50 m/min for the core yarn and 500 m/min for the sheath yarn
(Example 6), and 20 m/min for the core yarn and 1000 m/min for the sheath yarn (Example
7).
[0128] In Example 6 in which the feed rate ratio was decreased, the loop size was slightly
smaller than that in Example 1, but the stretchability which is a characteristic of
the present invention was comparable and the texture was good.
[0129] In Example 7 in which the feed rate ratio was increased, although the size of the
loop was 60.1 mm, which was larger than that in Example 1, the loop had little slack.
Regarding the texture, the yarn had flexibility and excellent bulkiness, and had a
structure in which cutting and slack of the sheath yarn were also suppressed, and
the yarn was also good in unwinding properties. The results are shown in Table 3.
Example 8
[0130] All the procedures were carried out in accordance with Example 7 except that the
airflow rate was changed to 500 m/s.
[0131] In Example 8, although the tension between the nozzle and the take-up roller was
decreased by increasing the airflow rate and the traveling of the textured yarn was
slightly disturbed, the textured yarn was collected without any problem. In the textured
yarn, slack of the loop was rarely seen, but the yarn had no problem in the unwinding
properties, and a bulky yarn having the stretchability, which is a characteristic
of the present invention, was successfully collected. The results are shown in Table
3.
[Table 3]
|
Example 5 |
Example 6 |
Example 7 |
Example 8 |
Core yarn |
A polymer |
- |
3GT |
PET 1 |
PET 1 |
PET 1 |
B polymer |
- |
PET 2 |
PET 2 |
PET 2 |
PET 2 |
A/B ratio |
- |
50/50 |
50/50 |
50/50 |
50/50 |
Cross-sectional shape |
|
Side-by-side Fig. 4 (4-1) |
Side-by-side Fig. 4 (4-1) |
Side-by-side Fig. 4 (4-1) |
Side-by-side Fig. 4 (4-1) |
Single yarn fineness |
dtex/F |
3.0 |
7.0 |
7.0 |
7.0 |
Sheath yarn |
Polymer type |
- |
PET 3 |
PET 3 |
PET 3 |
PET 3 |
Cross-sectional shape |
- |
Single hollow |
Single hollow |
Single hollow |
Single hollow |
Single yarn fineness |
dtex/F |
6.5 |
6.5 |
6.5 |
6.5 |
Density |
g/cm3 |
0.97 |
0.97 |
0.97 |
0.97 |
Fluid processing |
Feed rate |
Core yarn feed rate |
m/min |
50 |
50 |
20 |
20 |
Sheath yarn feed rate |
m/min |
1000 |
500 |
1000 |
1000 |
Feed rate ratio |
- |
20 |
10 |
50 |
50 |
Fineness ratio |
Sheath/core |
- |
2.2 |
0.9 |
0.9 |
0.9 |
Nozzle |
Airflow rate |
m/s |
400 |
400 |
400 |
500 |
Airflow rate/yarn speed |
- |
480 |
480 |
1200 |
1500 |
Injection angle |
° |
20 |
20 |
20 |
20 |
Intermingling/ opening within nozzle |
- |
Absent |
Absent |
Absent |
Absent |
Turning point (distance/airflow rate) |
s |
0.0001 |
0.0001 |
0.0001 |
0.00011 |
Bulky yarn |
Loop |
Size (protrusion) |
mm |
34.9 |
26.9 |
60.1 |
36.0 |
Number |
Number/mm |
8 |
21 |
30 |
30 |
Breakage (breaking point) |
- |
Absent (0.0) |
Absent (0.0) |
Absent (0.1) |
Absent (0.0) |
Three-dimensional crimp |
- |
Present |
Present |
Present |
Present |
Curvature radius |
mm |
7.5 |
4.5 |
6.3 |
6.0 |
Characteristic |
Strength |
cN/dtex |
3.5 |
3.9 |
4.0 |
3.7 |
Elastic modulus |
cN/dtex |
50 |
78 |
70 |
71 |
10% modulus |
cN/dtex |
1.3 |
1.5 |
1.5 |
1.5 |
Extension recovery rate |
% |
52 |
84 |
75 |
73 |
Fiber extension ratio |
- |
0.7 |
1.2 |
1.0 |
1.0 |
Fiber length restoration rate |
% |
55 |
89 |
80 |
78 |
Coefficient of static friction between fibers |
- |
0.1 |
0.1 |
0.2 |
0.3 |
Fastener phenomenon |
- |
S |
S |
A |
B |
Touch feeling |
- |
S |
A |
S |
A |
Bulkiness |
inch3/20 g |
381 |
335 |
667 |
400 |
Examples 9 and 10
[0132] All the procedures were carried out in accordance with Example 2 except that the
ratio of A polymer to B polymer was changed to 60/40 (Example 9) and 30/70 (Example
10) with respect to the conjugate fiber used for the core yarn.
[0133] In Example 9, there was no significant difference in the crimp form of the core yarn,
and the form and the like of the loop of the textured yarn was not greatly affected.
Therefore, the yarn had almost the same characteristics as those in Example 2.
[0134] In Example 10, the number of loops was reduced due to the small crimp form of the
core yarn, and the extension recovery rate was increased as compared with that in
Example 2. The results are shown in Table 4.
Examples 11 and 12
[0135] All the procedures were carried out in accordance with Example 2 except that an eccentric
sheath-core conjugate fiber of PET 1/PET 2 (Example 11) and PBT/PET 2 (Example 12)
obtained using the composite spinneret that provides an eccentric sheath-core conjugate
cross section illustrated in Fig. 4 (4-2) was used as the core yarn, and the distance
of the turning point was set to 0.0006.
[0136] In Example 11, the number of loops was slightly smaller than that in Example 2. On
the other hand, in Example 12, the number of loops was increased as compared with
that in Example 4, and the binding between the sheath yarn and the core yarn was increased.
Therefore, the stretchability was improved. The results are shown in Table 4.
Comparative Example 4
[0137] All the procedure was carried out according to Comparative Example 2 except that
the hollow cross-section PET fiber used in Comparative Example 2 was used as a core
yarn and the 3GT/PET 2 side-by-side conjugate fiber used in Example 5 was used as
a sheath yarn.
[0138] In the sample of Comparative Example 4, the sheath yarn exhibited a three-dimensional
crimped shape after the heat treatment, but the fiber forming the loop was very fine
and had a curvature radius of several tens of micrometers, and the sheath yarn breakages
were observed in some places (breakage present: 0.4). Due to the exhibition of this
crimped form, the loop of the sheath yarn greatly shrunk as compared with that before
the heat treatment, and few loops exceeding 0.6 mm from the surface of the yarn were
present. For this reason, although the touch feeling of the textured yarn was a unique
rubber-like feeling, the yarn did not have the bulkiness and flexibility which are
the objects of the present invention. Because of the microfine crimp on the micrometer
order, breakage of the sheath yarn and unevenness of the protrusion of the loop, 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 4]
|
Example 9 |
Example 10 |
Example 11 |
Example 12 |
Comparative Example 4 |
Core yarn |
A polymer |
- |
PET 1 |
PET 1 |
PET 1 |
PBT |
PET 3 |
B polymer |
- |
PET 2 |
PET 2 |
PET 2 |
PET 2 |
- |
A/B ratio |
- |
60/40 |
30/70 |
50/50 |
50/50 |
- |
Cross-sectional shape |
|
Side-by-side Fig. 4 (4-1) |
Side-by-side Fig. 4 (4-1) |
Eccentric core-in-sheath Fig. 4 (4-2) |
Eccentric core-in-sheath Fig. 4 (4-2) |
Single hollow |
Single yarn fineness |
dtex/F |
3.0 |
3.0 |
3.0 |
3.0 |
6.5 |
Sheath yarn |
Polymer type |
- |
PET 3 |
PET 3 |
PET 3 |
PET 3 |
3GT/PET 2 |
Cross-sectional shape |
- |
Single hollow |
Single hollow |
Single hollow |
Single hollow |
Side-by-side Fig. 4 (4-1) |
Single yarn fineness |
dtex/F |
6.5 |
6.5 |
6.5 |
6.5 |
6.5 |
Density |
g/cm3 |
0.97 |
0.97 |
0.97 |
0.97 |
1.36 |
Fluid processing |
Feed rate |
Core yarn feed rate |
m/min |
50 |
50 |
50 |
50 |
50 |
Sheath yarn feed rate |
m/min |
1000 |
1000 |
1000 |
1000 |
1000 |
Feed rate ratio |
- |
20 |
20 |
20 |
20 |
20 |
Fineness ratio |
Sheath/core |
- |
2.2 |
2.2 |
2.2 |
2.2 |
1.0 |
Nozzle |
Airflow rate |
m/s |
400 |
400 |
400 |
400 |
200 |
Airflow rate/yarn speed |
- |
480 |
480 |
480 |
480 |
240 |
Injection angle |
° |
20 |
20 |
45 |
45 |
90 |
Intermingling/opening within nozzle |
- |
Absent |
Absent |
Absent |
Absent |
Present |
Turning point (distance/airflow rate) |
s |
0.0001 |
0.0001 |
0.0006 |
0.0006 |
0 |
Bulky yarn |
Loop |
Size (protrusion) |
mm |
32.0 |
26.2 |
31.9 |
21.7 |
0.6 |
Number |
Number/mm |
19 |
15 |
18 |
13 |
93 |
Breakage (breaking point) |
- |
Absent (0.0) |
Absent (0.0) |
Absent (0.0) |
Absent (0.0) |
Present (0.4) |
Three-dimensional crimp |
- |
Present |
Present |
Present |
Present |
Absent |
Curvature radius |
mm |
6.3 |
6.1 |
5.0 |
5.0 |
0.3 |
Characteristic |
Strength |
cN/dtex |
3.0 |
3.0 |
4.8 |
4.8 |
1.4 |
Elastic modulus |
cN/dtex |
70 |
70 |
69 |
51 |
104 |
10% modulus |
cN/dtex |
1.5 |
1.5 |
1.5 |
1.5 |
2.4 |
Extension recovery rate |
% |
88 |
94 |
88 |
100 |
48 |
Fiber extension ratio |
- |
1.2 |
1.3 |
1.2 |
1.4 |
Breakage |
Fiber length restoration rate |
% |
94 |
100 |
94 |
100 |
- |
Coefficient of static friction between fibers |
- |
0.1 |
0.1 |
0.1 |
0.1 |
0.4 |
Fastener phenomenon |
- |
S |
S |
S |
S |
B |
Touch feeling |
- |
S |
S |
A |
A |
C |
Bulkiness |
inch3/20 g |
426 |
349 |
424 |
325 |
6 |
Example 13
[0139] To increase the stretchability and flexibility of the textured yarn, the 3GT used
in A polymer of Example 5 was melted at 275°C, weighed, flowed into a spinning pack,
and discharged from a hollow cross-sectional discharge hole in which three slits (width
of 0.1 mm, reference sign 23 in Fig. 8) as exemplified in Fig. 8 were concentrically
disposed to give a yarn with a hollow rate of 10%. Cooling air at 20°C was blown against
the discharged yarn at a flow rate of 20 m/min to cool and solidify the yarn, and
after application of a spinning oil agent, an undrawn yarn was wound up at a spinning
speed of 1500 m/min. The procedures were carried out all in accordance with those
in Example 1 except that a fiber (single yarn fineness: 7.0 dtex) obtained by drawing
the wound undrawn yarn 2.8 times at a drawing speed of 800 m/min between rollers heated
at 70°C and 130°C was used as the core yarn.
[0140] In Example 13, a bulky yarn having 22/mm loops formed by a sheath yarn protruding
by 38.0 mm on average from the surface was obtained. The protruding loops were excellent
in size and period uniformity. The sheath yarn of the textured yarn had a three-dimensional
crimped structure with a curvature radius of 5.7 mm on the millimeter order, and the
sheath yarn had continuously formed loops without any broken portions. (number of
broken portions: 0.0)
[0141] In the bulky yarn, the sheath yarn that had continuously formed loops had a three-dimensional
crimped structure, the coefficient of static friction between fibers was 0.1, the
bulky yarn had no problem in the unwinding properties, and the yarn was successfully
smoothly unwound from the drum around which the yarn was wound without tangling or
the like (unwinding properties: S). In particular, the 10% modulus that represents
the resistance at the time of expansion and contraction was as low as 1.2 cN/dtex,
and the fiber restoration rate after the load application was 100%. Thus, the yarn
was excellent in anti-flattening properties, and had stretchability with a flexible
texture that allows the yarn to stretch well at low stress (texture: S). The results
are shown in Table 5.
Example 14
[0142] To further increase the stretchability and the anti-flattening properties compared
to Example 13, all the procedures were carried out in accordance with Example 13 except
that the polymer was changed to a PBT elastomer ("Hytrel" manufactured by Du Pont-Toray
Co., Ltd.) and a core yarn produced at a spinning temperature of 260°C was collected.
[0143] In Example 14, the polymer type of the core yarn was changed to a PBT elastomer excellent
in flexibility, and the bulky yarn had a 10% modulus significantly lowered as compared
with that in Example 13. The yarn had both excellent stretchability and excellent
flexibility. Also, the fiber length restoration rate was greatly improved, and there
was almost no flattening even when the yarn was deformed by application of high stress.
Thus, it was found that the yarn is a material suitably usable in a site to which
deformation compression is applied repeatedly and a site that is extended and deformed
largely when used for clothing. The results are shown in Table 5.
Example 15
[0144] Polypropylene (PP: MFR = 9 g/10 min) as an island component and PET3 (0.65 dl/g)
used in Example 1 as a sea component were separately melted at 265°C and at 300°C,
respectively, weighed, and flowed into a spinning pack. A hollow islands-in-sea conjugate
yarn as exemplified in Fig. 5 having a hollow portion at the center of the fiber cross
section and having a sea-island structure in a donut shape around the hollow portion
was melt-spun at a spin block temperature of 280°C. A composite spinneret consisting
of a weighing plate and a distribution plate described in Japanese Patent Laid-open
Publication No.
2011-174215 was used for the spinneret incorporated in the spinning pack. The distribution plate
used was a distribution plate in which a circular space not provided with a distribution
hole was provided in the center of the plate, the distribution holes of the sea component
polymer were arranged in a ring shape around the periphery of the circular space,
and further one distribution hole of the island component polymer was surrounded by
six distribution hole of the sea component polymer on the outer circumference. To
the conjugate polymer stream discharged at a conjugate ratio of islands/sea = 30/70,
cooling air at 20°C was blown from a side at a flow rate of 100 m/min to cool and
solidify the stream. Then, an oil agent was applied to the resulting product, and
the undrawn yarn was wound at a spinning rate of 1200 m/min. Then, the yarn was drawn
2.9 times at a drawing rate of 600 m/min between rollers heated at 90°C and 130°C
to obtain a drawn yarn having a fineness of 78 dtex, a number of filaments of 12,
32 islands per filament, a hollow rate of 30%, and a density of 0.87 g/cm
3. Since cooling air was applied to the hollow islands-in-sea conjugate yarn at high
speed, the yarn was cooled asymmetrically between the left and right of the fiber,
and gently crimped after the heat treatment.
[0145] In the process shown in Fig. 6, the obtained hollow islands-in-sea conjugate yarn
was supplied one by one to the two supply rollers, and sucked with a suction nozzle
with one of the supply rollers rotated at a speed of 50 m/min and the other at a speed
of 1000 m/min. In the suction nozzle, compressed air was injected at 20° against the
traveling yarn at an airflow rate of 400 m/s, and the core yarn and the sheath yarn
were jetted out together with the accompanying airflow from the nozzle without entangling.
The yarn injected from the nozzle was made to travel for 1.0 × 10
-4 seconds with the airflow, the yarn path was changed using a ceramic guide, and the
textured yarn having the loop formed by the sheath yarn was taken up with a take-up
roller at 50 m/min.
[0146] Subsequently, the textured yarn was guided to a tube heater via rollers and heat-treated
with heated air at 150°C for 10 seconds to set the form of the bulky yarn and to cause
a three-dimensional crimp to appear in the sheath yarn. The bulky yarn was wound on
a drum at 52 m/min by a tension control type winder installed behind the tube heater.
Furthermore, a silicone oil agent containing polysiloxane at a concentration of 8
wt% was uniformly sprayed to the collected bulky yarn with a spray so that the final
amount of polysiloxane attached was 1 wt% with respect to the bulky yarn, and the
resulting product was heat-treated at a temperature of 165°C for 20 minutes to obtain
a textured yarn.
[0147] The bulky yarn collected in Example 15 had a structure in which a loop formed by
a sheath yarn protruded from the surface of the yarn by 21.0 mm on average, and the
number of loops was 22/mm. The protruding loops were excellent in size and period
uniformity.
[0148] The core yarn and the sheath yarn had a three-dimensional crimped structure with
a curvature radius of 4.5 mm on the millimeter order, and the sheath yarn had continuously
formed loops without any broken portions.
(number of broken portions: 0.0)
[0149] In the bulky yarn, the sheath yarn that had continuously formed loops had a three-dimensional
crimped structure, the coefficient of static friction between fibers was 0.1, the
unwinding from the drum around which the yarn was wound was smooth, and thus, the
yarn was excellent in unwinding properties (unwinding properties: S). The yarn had
bulkiness derived from the specific structure of the present invention and had a texture
excellent also in flexibility (texture: S). In Example 15, the stretchability was
lower than that in Example 1, but the bulkiness evaluation showed excellent performance
of 645 inch
3/20 g. The results are shown in Table 5.
Examples 16 and 17
[0150] Procedures were carried out in accordance with Example 15 except that the island/sea
conjugate ratio and the drawn yarn density of the hollow islands-in-sea conjugate
yarn used in the sheath yarn were changed to an island/sea ratio of 20/80 and a density
of 0.90 g/cm
3 (Example 16), and an island/sea ratio of 10/90 and a density of 0.93 g/cm
3 (Example 17).
[0151] The bulky yarn collected in Example 16 had continuously formed loops of the sheath
yarn without broken portions. The sheath yarn had a three-dimensional crimped structure,
was excellent in unwinding properties from the drum around which the yarn was wound
(unwinding properties: S), and had a texture excellent in flexibility (texture: S).
In bulkiness evaluation, the yarn showed excellent bulkiness of 606 inch
3/20 g.
[0152] The bulky yarn collected in Example 17 had continuously formed loops of the sheath
yarn without broken portions. The sheath yarn had a three-dimensional crimped structure,
was excellent in unwinding properties from the drum around which the yarn was wound
(unwinding properties: S), and had a texture excellent in flexibility (texture: S).
In bulkiness evaluation, the yarn showed excellent bulkiness of 581 inch
3/20 g. The results are shown in Table 5.
[Table 5]
|
Example 13 |
Example 14 |
Example 15 |
Example 16 |
Example 17 |
Core yarn |
A polymer |
- |
3GT |
"Hytrel" |
PP |
PP |
PP |
B polymer |
- |
- |
- |
PET 3 |
PET 3 |
PET 3 |
A/B ratio |
- |
- |
- |
30/70 |
20/80 |
10/90 |
Cross-sectional shape |
|
Single hollow |
Single hollow |
Sea-island hollow Fig. 5 |
Sea-island hollow Fig. 5 |
Sea-island hollow Fig. 5 |
Single yarn fineness |
dtex/F |
7.0 |
7.0 |
6.5 |
6.5 |
6.5 |
Sheath yarn |
A polymer |
- |
PET 3 |
PET 3 |
PP |
PP |
PP |
B polymer |
- |
- |
- |
PET 3 |
PET 3 |
PET 3 |
Cross-sectional shape |
- |
Single hollow |
Single hollow |
Sea-island hollow Fig. 5 |
Sea-island hollow Fig. 5 |
Sea-island hollow Fig. 5 |
Single yarn fineness |
dtex/F |
6.5 |
6.5 |
6.5 |
6.5 |
6.5 |
Density |
g/cm3 |
0.97 |
0.97 |
0.87 |
0.90 |
0.93 |
Fluid processing |
Feed rate |
Core yarn feed rate |
m/min |
50 |
50 |
50 |
50 |
50 |
Sheath yarn feed rate |
m/min |
1000 |
1000 |
1000 |
1000 |
1000 |
Feed rate ratio |
- |
20 |
20 |
20 |
20 |
20 |
Fineness ratio |
Sheath/core |
- |
0.9 |
0.9 |
0.9 |
0.9 |
0.9 |
Nozzle |
Airflow rate |
m/s |
400 |
400 |
400 |
400 |
400 |
Airflow rate/yarn speed |
- |
480 |
480 |
480 |
480 |
480 |
Injection angle |
° |
20 |
20 |
20 |
20 |
20 |
Intermingling/opening within nozzle |
- |
Absent |
Absent |
Absent |
Absent |
Absent |
Turning point (distance/airflow rate) |
s |
0.0001 |
0.0001 |
0.0001 |
0.0001 |
0.0001 |
Bulky yarn |
Loop |
Size (protrusion) |
mm |
38.0 |
21.0 |
21.0 |
23.0 |
18.0 |
Number |
Number/mm |
22 |
18 |
22 |
27 |
18 |
Breakage (breaking point) |
- |
Absent (0.0) |
Absent (0.0) |
Absent (0.0) |
Absent (0.0) |
Present (0.4) |
Three-dimensional crimp |
- |
Present |
Present |
Present |
Present |
Absent |
Curvature radius |
mm |
5.7 |
5.2 |
4.5 |
4.1 |
3.9 |
Characteristic |
Strength |
cN/dtex |
2.6 |
3.4 |
3.6 |
3.4 |
3.5 |
Elastic modulus |
cN/dtex |
26 |
32 |
74 |
61 |
52 |
10% modulus |
cN/dtex |
1.2 |
0.2 |
2.4 |
1.9 |
1.5 |
Extension recovery rate |
% |
88 |
93 |
80 |
81 |
83 |
Fiber extension ratio |
- |
2.6 |
2.8 |
1.1 |
1.1 |
1.2 |
Fiber length restoration rate |
% |
100 |
100 |
85 |
86 |
80 |
Coefficient of static friction between fibers |
- |
0.1 |
0.1 |
0.1 |
0.1 |
0.1 |
Fastener phenomenon |
- |
S |
S |
S |
S |
S |
Touch feeling |
- |
S |
S |
A |
A |
A |
Bulkiness |
inch3/20 g |
374 |
327 |
645 |
606 |
581 |
Examples 18 and 19
[0153] Procedures were carried out all in accordance with Example 12 except that the eccentric
sheath-core conjugate fiber of PBT/PET 2 used in Example 12 was used as a core yarn
and the feed rate was changed to 50 m/min for the core yarn and 500 m/min for the
sheath yarn (Example 18), and 20 m/min for the core yarn and 1000 m/min for the sheath
yarn (Example 19).
[0154] In Example 18 in which the feed rate ratio was decreased, the loop size was slightly
smaller than that in Example 12, but the yarn had good stretchability which is a characteristic
of the present invention and exhibited an excellent texture.
[0155] In Example 19 in which the feed rate ratio was increased, although the size of the
loop was 38.0 mm, which was larger than that in Example 12, the loop had little slack.
Regarding the texture, the yarn had flexibility and excellent bulkiness, and had a
structure in which cutting and slack of the sheath yarn were also suppressed, and
the yarn was also good in unwinding properties. The results are shown in Table 6.
Examples 20 and 21
[0156] All the procedures were carried out in accordance with Example 15 except that the
eccentric sheath-core conjugate fiber of PBT/PET 2 used in Example 12 was used as
a core yarn and the PP/PET3 hollow islands-in-sea conjugate yarn used in Example 15
was used as a sheath yarn (Example 20). As a case where the feed rate ratio is changed,
a textured yarn obtained at a feed rate of the core yarn of 20 m/min and a feed rate
of the sheath yarn of 1000 m/min was also collected (Example 21).
[0157] In Example 20, loops having resilience derived from the PET component was formed
even at low density, and as in Example 15, the yarn exhibited excellent bulkiness
and good stretchability derived from the eccentric sheath-core conjugate yarn arranged
as the core yarn. Thus, the yarn had properties that were not conventionally achieved.
[0158] In Example 21, by further increasing the sheath/core ratio, the loop of the sheath
yarn was further enlarged, and the bulkiness was further improved as compared with
Example 20. In Example 21, although the loop was enlarged, the loop was excellent
in uniformity in the fiber axis direction of the textured yarn, and looseness of the
loop was not observed. In the yarn, the sea-island hollow fiber having a large crimp
was wound around the core yarn having stretchability due to crimping to make the loop
self-stand. Owing to the effect of the PET component in addition to such loops, the
yarn had comfortable resilience. The results are shown in Table 6.
Example 22
[0159] The procedures were carried out in accordance with Example 20 except that a high
elastic yarn made of the PBT elastomer ("Hytrel") used in Example 14 was used as the
core yarn.
[0160] The textured yarn of Example 22 exhibited excellent stretchability by the use of
an elastic yarn that extends and deforms under low stress as a core yarn, the fiber
length was not changed even when the yarn was deformed to a relatively high degree,
and thus the yarn had excellent resilience. As in Example 20, a sea-island hollow
fiber was adopted as the sheath yarn, and the bulkiness was also excellent.
[Table 6]
|
Example 18 |
Example 19 |
Example 20 |
Example 21 |
Example 22 |
Core yarn |
A polymer |
- |
PBT |
PBT |
PBT |
PBT |
"Hytrel" |
B polymer |
- |
PET 2 |
PET 2 |
PET 2 |
PET 2 |
- |
A/B ratio |
- |
50/50 |
50/50 |
50/50 |
50/50 |
- |
Cross-sectional shape |
|
Eccentric core-in-sheath Fig. 4 (4-2) |
Eccentric core-in-sheath Fig. 4 (4-2) |
Eccentric core-in-sheath Fig. 4 (4-2) |
Eccentric core-in-sheath Fig. 4 (4-2) |
Single hollow |
Single yarn fineness |
dtex/F |
3.0 |
3.0 |
3.0 |
3.0 |
7.0 |
Sheath yarn |
A polymer |
- |
PET 3 |
PET 3 |
PP |
PP |
PP |
B polymer |
- |
- |
- |
PET 3 |
PET 3 |
PET 3 |
Cross-sectional shape |
- |
Single hollow |
Single hollow |
Sea-island hollow Fig. 5 |
Sea-island hollow Fig. 5 |
Sea-island hollow Fig. 5 |
Single yarn fineness |
dtex/F |
6.5 |
6.5 |
6.5 |
6.5 |
6.5 |
Density |
g/cm3 |
0.97 |
0.97 |
0.87 |
0.87 |
0.87 |
Fluid processing |
Feed rate |
Core yarn feed rate |
m/min |
50 |
20 |
50 |
20 |
50 |
Sheath yarn feed rate |
m/min |
500 |
1000 |
1000 |
1000 |
1000 |
Feed rate ratio |
- |
10 |
50 |
20 |
50 |
20 |
Fineness ratio |
Sheath/core |
- |
2.2 |
2.2 |
0.9 |
2.2 |
0.9 |
Nozzle |
Airflow rate |
m/s |
400 |
400 |
400 |
400 |
400 |
Airflow rate/yarn speed |
- |
480 |
1200 |
480 |
1200 |
480 |
Injection angle |
° |
20 |
20 |
20 |
20 |
20 |
Intermingling/opening within nozzle |
- |
Absent |
Absent |
Absent |
Absent |
Absent |
Turning point (distance/airflow rate) |
s |
0.0001 |
0.0001 |
0.0001 |
0.0001 |
0.0001 |
Bulky yarn |
Loop |
Size (protrusion) |
mm |
18.0 |
38.0 |
21.0 |
38.0 |
18.0 |
Number |
Number /mm |
23 |
18 |
22 |
18 |
18 |
Breakage (breaking point) |
- |
Absent (0.0) |
Absent (0.0) |
Absent (0.0) |
Absent (0.0) |
Present (0.4) |
Three-dimensional crimp |
- |
Present |
Present |
Present |
Present |
Absent |
Curvature radius |
mm |
5.1 |
5.2 |
4.5 |
4.5 |
4.5 |
Characteristic |
Strength |
cN/dtex |
4.8 |
3.8 |
4.8 |
3.8 |
3.4 |
Elastic modulus |
cN/dtex |
51 |
46 |
51 |
46 |
32 |
10% modulus |
cN/dtex |
1.4 |
1.4 |
2.4 |
1.9 |
1.5 |
Extension recovery rate |
% |
91 |
90 |
80 |
81 |
83 |
Fiber extension ratio |
- |
1.3 |
1.3 |
1.1 |
1.3 |
2.8 |
Fiber length restoration rate |
% |
97 |
100 |
85 |
86 |
100 |
Coefficient of static friction between fibers |
- |
0.1 |
0.1 |
0.1 |
0.1 |
0.1 |
Fastener phenomenon |
- |
A |
S |
S |
S |
S |
Touch feeling |
- |
S |
S |
A |
A |
A |
Bulkiness |
inch3/20 g |
352 |
633 |
671 |
702 |
680 |
DESCRIPTION OF REFERENCE SIGNS
[0161]
- 1:
- Sheath yarn
- 2:
- Core yarn
- 3:
- Yarn surface
- 4:
- Yarn path guide
- 5:
- Distance from yarn surface
- 6:
- Curve of three-dimensional crimp
- 7:
- A polymer
- 8:
- B polymer
- 9:
- Hollow portion
- 10:
- Island component
- 11:
- Sea component
- 12:
- Suction nozzle
- 13:
- Turning point
- 14:
- Textured yarn
- 15:
- Take-up roller
- 16:
- Heater
- 17:
- Delivery roller
- 18:
- Winder
- 19:
- Supply roller
- 20:
- Core yarn
- 21:
- Sheath yarn
- 22:
- Injection angle of compressed air
- 23:
- Slit-shaped discharge hole