U.S. patent application number 14/448194 was filed with the patent office on 2014-11-20 for composite fiber, method for producing polyurethane elastomer fabric, and polyurethane elastomer fabric.
This patent application is currently assigned to KURARAY CO., LTD.. The applicant listed for this patent is KURARAY CO., LTD.. Invention is credited to Eiji AKIBA, Shunichi HAYASHI, Nobuhiro KOGA, Hitoshi NAKATSUKA.
Application Number | 20140342629 14/448194 |
Document ID | / |
Family ID | 48905134 |
Filed Date | 2014-11-20 |
United States Patent
Application |
20140342629 |
Kind Code |
A1 |
NAKATSUKA; Hitoshi ; et
al. |
November 20, 2014 |
COMPOSITE FIBER, METHOD FOR PRODUCING POLYURETHANE ELASTOMER
FABRIC, AND POLYURETHANE ELASTOMER FABRIC
Abstract
Provided is a composite fiber capable of forming a fabric giving
a good wearing feeling to a human body. This composite fiber is
composed of a polyurethane elastomer having a glass transition
temperature of 15 to 50.degree. C. as a component A, and a readily
soluble thermoplastic polymer as a component B. In a cross section
of the fiber, the component A constitutes a core, and the component
B covers 70% or longer of the circumference of the component A. The
component B may be, for example, a readily soluble polyester or
thermoplastic polyvinyl alcohol-based polymer. The composite ratio
(mass ratio) of the component A to the component B may be 90:10 to
40:60.
Inventors: |
NAKATSUKA; Hitoshi;
(Kurashiki-shi, JP) ; KOGA; Nobuhiro;
(Kurashiki-shi, JP) ; AKIBA; Eiji; (Osaka-shi,
JP) ; HAYASHI; Shunichi; (Shibuya-ku, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KURARAY CO., LTD. |
Kurashiki-shi |
|
JP |
|
|
Assignee: |
KURARAY CO., LTD.
Kurashiki-shi
JP
|
Family ID: |
48905134 |
Appl. No.: |
14/448194 |
Filed: |
July 31, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2013/051575 |
Jan 25, 2013 |
|
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14448194 |
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Current U.S.
Class: |
442/181 ; 28/168;
428/221; 428/373; 442/304 |
Current CPC
Class: |
Y10T 442/40 20150401;
D01F 6/70 20130101; D06Q 1/02 20130101; Y10T 428/249921 20150401;
D06H 7/228 20130101; Y10T 442/30 20150401; D01F 8/16 20130101; D10B
2321/06 20130101; D10B 2331/10 20130101; Y10T 428/2929 20150115;
D03D 15/08 20130101 |
Class at
Publication: |
442/181 ;
428/373; 428/221; 442/304; 28/168 |
International
Class: |
D01F 8/16 20060101
D01F008/16; D06H 7/22 20060101 D06H007/22 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 31, 2012 |
JP |
2012-017550 |
Claims
1. A composite fiber comprising: a polyurethane elastomer having a
glass transition temperature of 15 to 50.degree. C. as a component
A, the component A constituting a core in a cross section of the
fiber, and a readily soluble thermoplastic polymer as a component
B, the component B covering 70% or longer of the circumference of
the component A in the cross section.
2. The composite fiber according to claim 1, wherein the component
B comprises at least one selected from the group consisting of a
readily soluble polyester and a thermoplastic polyvinyl
alcohol-based polymer.
3. The composite fiber according to claim 1, which has a single
fiber fineness of 0.3 to 50 dtex.
4. The composite fiber according to claim 1, wherein the composite
ratio (mass ratio) of the component A to the component B is 90:10
to 40:60.
5. The composite fiber according to claim 1, which has a
core-sheath structure in which the component A is a core component
and the component B is a sheath component.
6. A method for producing a polyurethane elastomer fabric,
comprising: preparing a composite fiber as claimed in claim 1;
producing a fabric comprising the composite fiber by using the
composite fiber; and removing the component B from the fabric to
produce a polyurethane elastomer fabric comprising a polyurethane
elastomer monocomponent fiber.
7. A polyurethane elastomer fabric produced by a method as claimed
in claim 6 comprising a polyurethane elastomer monocomponent
fiber.
8. The polyurethane elastomer fabric according to claim 7, wherein
the fabric comprises a polyurethane elastomer monocomponent fiber
having a single fiber fineness of 0.3 to 50 dtex.
9. The polyurethane elastomer fabric according to claim 7, wherein
the fabric has a peak value of mechanical dynamic loss tangent (tan
.theta.) of 0.2 to 1.0.
10. The polyurethane elastomer fabric according to claim 7, wherein
the fabric comprises a polyurethane elastomer monocomponent fiber
in a continuous fiber form.
11. The polyurethane elastomer fabric according to claim 7, wherein
the fabric is a woven or knitted fabric.
Description
CROSS REFERENCE TO THE RELATED APPLICATION
[0001] This application is a continuation application, under 35
U.S.C. .sctn.111(a), of international application No.
PCT/JP2013/051575, filed Jan. 25, 2013, which claims priority to
Japanese Patent Application No. 2012-017550, filed on Jan. 31,
2012, the entire disclosure of which is herein incorporated by
reference as a part of this application.
FIELD OF THE INVENTION
[0002] The present invention relates to a composite fiber
(conjugated or bicomponent or heterofil fiber) capable of forming a
fabric which gives a good wearing feeling to a human body.
BACKGROUND ART
[0003] Hitherto, foamed bodies made of a resin having a shape
memory property have been known. In these resin foams a desired
shape is memorized, for example, by following procedure: (i)
deforming an object at a temperature equal to or higher than the
glass transition temperature thereof, for example, a temperature
such as a polymer flow starting temperature, and then (ii) cooling
the object with keeping the deformed structure to a temperature of
the glass transition temperature or lower. For example, Patent
Document 1 discloses a shape-fitting resin foam which has a glass
transition temperature of 10 to 35.degree. C. and a loss tangent of
0.20 to 0.80 in a temperature range of 10 to 35.degree. C., a ratio
(G' max/G' min) of 3.0 to 30 in which G' means a storage elastic
modulus of the foam, G' max/G' min means a ratio of the maximum
value (G' max) relative to the minimum value (G' min) in a
temperature range of 10 to 35.degree. C.
[0004] On the other hand, fabrics to be worn on human bodies are
required to give a good wearing feeling. For example, Patent
Document 2 discloses a fabric having a glass transition temperature
of 15 to 35.degree. C., a peak value of a mechanical dynamic loss
tangent being present within this glass transition temperature
range, and a peak value of the mechanical dynamic loss tangent of
0.2 to 1.0 both inclusive, and states that this fabric is produced
from a single covered yarn in which a specific polyurethane
elastomer is used as a bare yarn and nylon is used as a covering
yarn.
RELATED ART DOCUMENTS
Patent Documents
[0005] [Patent Document 1] JP Laid-open Patent Publication No.
2009-35697 (Claim 1, and paragraphs [0009] to [0013]) [0006]
[Patent Document 2] JP Laid-open Patent Publication No. 2011-149108
(Claim 1, and paragraphs [0025] to [0034])
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0007] The shape-fitting resin foam described in Patent Document 1
is wearable in contact to the human body surface so that the resin
foam fits the shape of the body surface; however, such a resin foam
cannot follow a dynamic movement of a human body.
[0008] On the other hand, the fabric described in Patent Document 2
can follow a dynamic movement of a human body. However, a specific
polyurethane elastomer yarn which constitutes such a fabric is low
in glass transition temperature; thus, the elastomer yarn is poor
not only in fiber-processability but also in
fiber-to-fabric-processability during production process of the
fabric. Accordingly, in fact, it is difficult to produce a fabric
with such a polyurethane elastomer yarn.
[0009] Thus, an object of the present invention is to provide a
yarn which can be used for fabrics including a knitted fabric, a
woven fabric and a nonwoven fabric that give a good wearing feeling
during a dynamic movement of a human body, as well as can have good
processability during production process of a fabric.
Means for Solving the Problems
[0010] The inventors of the present invention have made various
investigations about a yarn suitable for clothing giving a good
wearing feeling even during the dynamic movement of a human body,
and have found that: having a low glass transition temperature in a
specific range is important for a specific polyurethane elastomer
yarn capable of giving a good wearing feeling to a human body in
order to improve the wearing feeling; however, when the
polyurethane elastomer has such a low glass transition temperature,
it is very difficult to process a polyurethane elastomer yarn
itself, and further to convert such a yarn into a fabric form.
Accordingly, the inventors have made further advanced researches
and finally found out that when a polyurethane elastomer is
combined with a specific thermoplastic polymer to produce a
composite fiber comprising two components into a conjugated form
that the circumstance of the polyurethane elastomer core is covered
with the thermoplastic polymer in a specific proportion, it is
possible to make favorably the combined components to have a fiber
form or fiber yarn as well as to make the fiber or yarn into a
fabric form even by using a polyurethane elastomer having a low
glass transition temperature. Thus, the present invention has been
accomplished.
[0011] That is, the present invention is a composite fiber,
comprising a polyurethane elastomer having a glass transition
temperature of 15 to 50.degree. C. as a component A, and a readily
soluble (or highly dissolvable to a solvent, readily removable with
a solvent) thermoplastic polymer as a component B; the component A
constituting a core in a cross section of the fiber, and the
component B covering 70% or longer of the circumference (external
boundary) of the component A.
[0012] In the fiber, the component B may comprise at least one
selected from a readily soluble polyester and a thermoplastic
polyvinyl alcohol-based polymer.
[0013] The composite fiber may have a single fiber fineness of
about 0.3 to 50 dtex. The composite ratio (mass ratio) of the
component A to the component B may be about A:B of 90:10 to
40:60.
[0014] The composite or conjugated structure of the composite fiber
is not particularly limited to a specific one, as far as the
component B attains the coverage percentage satisfying the
above-mentioned range. Thus, the composite fiber may have various
structures. Preferably, the composite fiber has a core-sheath
structure in which the component A is a core component and the
component B is a sheath component.
[0015] The present invention also includes a method for producing a
polyurethane elastomer fabric, including: preparing a composite
fiber such as described above; producing a fabric comprising the
composite fiber by using the composite fiber; and removing the
component B from the fabric so as to produce a polyurethane
elastomer fabric (a fabric comprising a polyurethane elastomer
monocomponent fiber).
[0016] The present invention also further includes a polyurethane
elastomer fabric produced by the above-mentioned method. Such a
fabric may comprise a polyurethane elastomer monocomponent fiber
(single polymer of polyurethane elastomer in a single fiber or
filament) having a single fiber fineness of 0.3 to 50 dtex.
[0017] Any combination of at least two constituent elements
disclosed in the claims and/or the specification and/or the
drawings is also included in the present invention. In particular,
any combination of two or more claims recited in the scope of
claims is included in the present invention.
Effects of the Invention
[0018] According to the present invention, since a specific
polyurethane elastomer is combined with a specific thermoplastic
polymer to be conjugate-spun so as to have a specific structure;
even when the used polyurethane elastomer is low in glass
transition temperature, fiber making processability with these
components can be improved.
[0019] In another aspect of the present invention, a composite
fiber excellent in spinnability can be obtained even when the fiber
has a small single fiber fineness.
[0020] Furthermore, according to the present invention, a
polyurethane elastomer fabric can be produced in an efficient way,
the fabric being high in flexibility in a temperature range of 15
to 50.degree. C., preferably of 15 to 45.degree. C., more
preferably of 15 to 35.degree. C., as well as being capable of
having a good wearing feeling and/or fitting during a dynamic
movement of a human body.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The present invention will be more clearly understood from
the following description of preferred embodiments thereof with
reference to the accompanying drawings. However, the embodiments
and the drawings are given only for the purpose of illustration and
explanation, and should not be used to limit the scope of this
invention. The scope of the present invention is determined by the
appended claims.
[0022] FIG. 1 is a photograph of a fiber cross section that shows
an example of a form of a composite fiber for obtaining the fiber
of the present invention;
[0023] FIG. 2 is a drawing illustrating an example of a fiber cross
section of a fiber of another embodiment of the present
invention;
[0024] FIG. 3 is a drawing illustrating an example of a fiber cross
section of a fiber of still another embodiment of the present
invention; and
[0025] FIG. 4 is a drawing illustrating an example of a fiber cross
section of a fiber of a yet another embodiment of the present
invention.
DESCRIPTION OF EMBODIMENTS
[0026] Hereinafter, the present invention will be described in
detail. The composite fiber of the present invention is a composite
fiber comprising a component A comprising a polyurethane elastomer
and a component B comprising a readily soluble thermoplastic
polymer capable of having an readily solubility in a solvent (or an
easily soluble thermoplastic polymer); and the component A
constitutes a core in a cross section of the fiber, and the
component B covers 70% or longer of the circumference of the
component A in the cross section.
[0027] The components A and B may be compatible with each other at
the interface therebetween. Preferably, these components are
incompatible with each other at the interface therebetween.
[0028] (Component A)
[0029] The polymer constituting the component A of the composite
fiber of the present invention is a polyurethane elastomer having a
glass transition temperature of 15 to 50.degree. C. The
polyurethane elastomer is not particularly limited to a specific
one, as far as the elastomer has such a low glass transition
temperature. The polyurethane elastomer having this property can be
obtained, for example, by blending a bifunctional diisocyanate
having a molecular weight of 160 to 310, a bifunctional polyol
having a molecular weight of 400 to 2000, and a chain extender that
is a diol or diamine having a molecular weight of 60 to 400 at a
molar ratio of (diisocyanate):(polyol):(chain extender) of 2.00 to
1.10:1.00:1.00 to 0.10, and then polymerizing the monomers to be
reacted in a prepolymer manner.
[0030] The bifunctional isocyanate may be appropriately selected
from any bifunctional isocyanate that can be used for producing the
polyurethane elastomer as described above, where the bifunctional
isocyanate has a molecular weight of 160 to 310. Preferred examples
of the bifunctional isocyanate include 2,4-toluene diisocyanate,
4,4'-diphenylmethane diisocyanate, carbodiimide-modified
4,4'-diphenylmethane isocyanate, hexamethylene diisocyanate and the
like. These bifunctional isocyanates may be used singly or in
combination of two or more.
[0031] The bifunctional polyol may be appropriately selected from
any bifunctional polyol that can be used for producing the
polyurethane elastomer as described above, where the bifunctional
polyol has a molecular weight of 400 to 2000. Preferred examples of
the bifunctional polyol include polypropylene glycol,
1,4-butaneglycol adipate, polytetramethylene glycol, polyethylene
glycol, and a propylene oxide adduct of bisphenol A. The
bifunctional polyol may be used to be further reacted with a
bifunctional carboxylic acid or a cyclic ether to obtain a reaction
product. Such a product is also treated as the bifunctional polyol.
These bifunctional polyols may be used singly or in combination of
two or more.
[0032] Each of the diol and the diamine that is used as the chain
extender may be appropriately selected from any diol and any
diamine that can be used for producing the polyurethane elastomer
as described above, where the chain extender (i.e., diol, diamine)
has a molecular weight of 60 to 400. Preferred examples of the diol
include ethylene glycol, 1,4-butaneglycol,
bis(2-hydroxyethyl)hydroquinone, an ethylene oxide adduct of
bisphenol A, and a propylene oxide adduct of bisphenol A. Preferred
examples of the diamine include ethylenediamine,
1,2-propylenediamine, 1,3-propylenediamine, m-xylylenediamine,
p-xylylenediamine, 4,4'-diphenylmethanediamine,
cyclohexylenediamine, 2,4-tolylenediamine, 2,6-tolylenediamine, and
hexamethylenediamine. These chain extenders may be used singly or
in combination of two or more.
[0033] The polyurethane elastomer is synthesized by using, as
starting materials, the bifunctional isocyanate, the bifunctional
polyol and the chain extender, and if necessary a catalyst, in a
prepolymer manner. According to the above synthesis, the component
A can be obtained in which the bifunctional isocyanate, the
bifunctional polyol and the chain extender are blended with one
another at a ratio of 2.00 to 1.10:1.00:1.00 to 0.10. If necessary,
the component A may contain various additives, for example, a
delustering agent (light-shielding agent) such as titanium oxide or
zinc oxide, an antioxidant, an ultraviolet absorber, and others. As
far as the polyurethane elastomer with a target property can be
obtained, these additives can be appropriately used either by
adding to the starting materials for the polymerization into the
component A, or by adding at any stage of the polymerization.
[0034] As the polyurethane elastomers having a glass transition
temperature of 15 to 50.degree. C., for example, the following
products are commercially available from SMP Technologies Inc.:
[0035] SMP MM-2520 (Tg=25.+-.3.degree. C.: 1,4-butanediol),
[0036] SMP MM-3520 (Tg=35.+-.3.degree. C.: 1,4-butanediol),
[0037] SMP MM-4520 (Tg=45.+-.3.degree. C.: 1,4-butanediol),
[0038] SMP MA-2520 (Tg=25.+-.3.degree. C.;
1,2-ethylenediamine),
[0039] SMP MA-3520 (Tg=35.+-.3.degree. C.; 1,2-ethylenediamine),
and
[0040] SMP MA-4520 (Tg=45.+-.3.degree. C.;
1,2-ethylenediamine).
[0041] Since the component A obtained by the polymerization has a
glass transition temperature of 15 to 50.degree. C., the component
A is high in flexibility at a normal or ambient temperature. When
the glass transition temperature of the component A is within a
range of 15 to 45.degree. C., more preferably of 15 to 40.degree.
C., in particular preferably of 15 to 35.degree. C., the glass
transition temperature of the component A is in the same range with
the surface temperature of human body. Thus, when such a component
is used for applied to a human body, the composite fiber comprising
the component A can give a good wearing feeling and/or close
fitting during a dynamic movement of the human body.
[0042] The glass transition point denotes a temperature at which
mechanical properties of the polymer elastomer change rapidly. In
the present invention, the glass transition point is defined as a
temperature at which the elastomer shows a peak with respect to the
mechanical dynamic loss tangent (referred to also as the tan
.delta. hereinafter). The tan .delta. is defined as the tangent of
the ratio of the loss elastic modulus G'' to the storage elastic
modulus G' (i.e., G''/G') at a frequency of 1 Hz. It should be
noted that the preferred glass transition temperature (Tg) is in a
temperature range of 25 to 40.degree. C., which is close to the
body surface temperature of any human body, and in particular
preferably in a temperature range of 25 to 35.degree. C.
[0043] (Component B)
[0044] The readily (or easily) soluble (removable or decomposable)
thermoplastic polymer, which is the component B of the composite
fiber of the present invention, may be any component as far as the
component B is melt-spinnable, as well as is easily dissolvable or
decomposable in/with a solvent or a chemical material in compare to
a polyurethane elastomer constituting the component A.
[0045] The readily soluble polymer may be a thermoplastic polymer
soluble/decomposable in/with, a solvent, for example, water
including a hot water, an alkali, or an acid. The readily soluble
polymer is preferably a readily soluble polyester-based polymer
which is soluble/decomposable in/with an alkali, or a readily
soluble thermoplastic polyvinyl alcohol-based polymer which is
soluble/decomposable in/with water.
[0046] When a readily soluble polyester-based polymer is used, the
preferable polyester is highly soluble in alkali. The readily
soluble polyester-based polymer may be, for example, a polar
group-containing copolymerized polyester or an aliphatic
polyester.
[0047] The polar group-containing copolymerized polyester may be a
copolymerized polyester obtained by copolymerizing the following
components with one another: 1 to 5% by mole of an ester-formable
sulfonic acid metal salt compound (for example, sodium
5-sulfoisophthalate or potassium 5-sulfoisophthalate); 5 to 30% by
mass of a polyalkylene glycol (for example, a
poly-C.sub.1-4-alkylene glycol such as a polypropylene glycol or a
polyethylene glycol); and a diol component and a dicarboxylic acid
component that are each conventionally used.
[0048] Examples of the aliphatic polyester include a polylactic
acid; a polyester from an aliphatic diol and an aliphatic
carboxylic acid, such as a poly(ethylene succinate), a
poly(butylene succinate), and a poly(butylene succinate co-butylene
adipate); a polyhydroxycarboxylic acid, such as a poly(glycolic
acid), a poly(3-hydroxybutyric acid), a poly(3-hydroxyvaleric
acid), and a poly(6-hydroxycaproic acid); and a
poly(.omega.-hydroxyalkanoate) such as a
poly(.epsilon.-caprolactone) and a poly(.delta.-valerolactone). Of
these aliphatic polyesters, the preferred one includes a polylactic
acid. The polylactic acid may be a poly D-lactic acid, a poly
L-lactic acid, or a mixture thereof.
[0049] The readily soluble polyester-based polymer is more
preferably a polyester which is readily soluble to alkali so that
the polyester is substantially completely dissolved (decomposed),
for example, in 60 minutes or less, preferably in 45 minutes or
less, more preferably in 30 minutes or less, in particular
preferably in 15 minutes or less when immersed in a 2% aqueous
sodium hydroxide solution that has a temperature of 100.degree. C.
at a bath ratio of 1:30.
[0050] When a water-soluble thermoplastic polyvinyl alcohol-based
polymer is used as the polymeric component B, the preferable
polyvinyl alcohol polymer may be a polyvinyl alcohol having a
viscosity-average polymerization degree of 200 to 500, a
saponification degree of 90 to 99.99% by mole (preferably 95 to 99%
by mole), and a melting point of 160 to 230.degree. C. The polymer
may be a homopolymer or a copolymer. The polymer is preferably a
copolymerized polyvinyl alcohol comprising a modifying component
such as an .alpha.-olefin having 4 or less carbon atoms (e.g.,
ethylene or propylene) in a proportion of 0.1 to 20% by mole
(preferably 5 to 15% by mole) from the viewpoint of the
melt-spinnability and water-solubility thereof, as well as the
physical properties of the obtained fibers.
[0051] The water-soluble thermoplastic polyvinyl alcohol-based
polymer is preferably, for example, a thermoplastic polyvinyl
alcohol-based polymer which is substantially completely dissolved
(decomposed), for example, in 60 minutes less, preferably in 50
minutes or less, more preferably in 30 minutes or less, in
particular preferably in 15 minutes or less when immersed in hot
water of 100.degree. C. at a bath ratio of 1:30.
[0052] (Method for Producing Composite Fiber)
[0053] The composite fiber of the present invention can be produced
so as to be combined or conjugated by using a composite-spinning
machine known in the prior art as far as the combination of the
polymeric component A and the polymeric component B has been
decided. The composite fiber can be produced by any spinning method
such as a method comprising melt-spinning these components at a low
or middle speed to obtain an as-spun filament, and drawing the
resultant filament; a direct spinning and drawing method comprising
spinning these components at a high speed; or a method comprising
spinning these components to obtain an as-spun filament, and
drawing the filament simultaneously with or followed by false
twisting.
[0054] The composite fiber of the present invention may have a
composite ratio of the component A polymer to the component B
polymer of preferably 90: to 40:60 (mass ratio), more preferably
85:15 to 60:40 (mass ratio). It is advisable to adjust the ratio
between the two components in accordance with the desired shape of
the fiber. If the proportion of the component A is too large, there
is a possibility that the fiber-forming processability, in
particular the process passing properties for producing fiber
products may be deteriorated, since the spun fibers may be mutually
stuck after winding. On the other hand, if the proportion of the
component B is too large, the fiber may not gain a good wearing
feeling to a human body, which feeling is a target of the
product.
[0055] In any cross section of the composite fiber of the present
invention, the component B does not need to cover the entire
surface of the fiber. In order to ensure winding processability
during fiber spinning, handle-ability after the winding, and
process passability during fiber product production, it is
important that the component A constitutes a core in the cross
section of the fiber, and the component B covers 70% or more of the
length of the circumference of the component A. The component B
preferably covers 80% or more of the length, and in particular
preferably covers 90% or more thereof.
[0056] The form of the conjugation in the present invention may be
a concentric form, an eccentric form or a multicore form as far as
the component B can be dissolved and removed by alkali treatment,
water treatment or some other dissolving treatment while the
component A is not cracked. The structure of the composite fiber
may be a core-sheath conjugated structure as illustrated in FIG. 1
in which the component A constitutes a core component, and the
component B constitutes a sheath component; a conjugated structure
as illustrated in FIG. 2 in which the component A constitutes a
core, and the component B intermittently covers the core; or a
conjugated structure as illustrated in FIG. 3 in which the
component A in a triangular form is covered with the component B.
The component A may have a shape, in the cross section of the
fiber, such as a circular cross-sectional shape, or an irregular
cross-sectional shape such as a triangle, a flat shape or a
multi-leaf shape. Furthermore, as illustrated in FIG. 4, the
component A may have a hollow structure therein. The component A
may have various cross-sectional shapes, for example, a one-hole
hollow shape, and a multi-hole hollow shape such as a two-hole
hollow shape, a hollow shape of more than two holes. The composite
fiber preferably has, out of these conjugated structures, a
core-sheath conjugated structure in which the component A
constitutes a core component and the component B constitutes a
sheath component.
[0057] The single fiber fineness of the composite fiber of the
present invention may be appropriately decided in accordance with a
purpose thereof, and is not particularly limited. The fineness is
selectable in a range of, for example, 0.3 to 50 dtex (preferably
0.3 to 40 dtex). The fineness is preferably 0.3 to 10 dtex
(preferably 0.3 to 5 dtex) to improve the close-fitting between
human body and the fiber product. It should be noted that,
according to the composite fiber of the present invention, a fiber
having a small fineness of 6 dtex or smaller can be obtained while
preventing fiber breakage. Such a fiber is usable in the form of a
long fiber (i.e., continuous filament), a short fiber (i.e.,
staple), or a short-cut fiber.
[0058] The composite fiber of the present invention obtained as
described above can be used as various fiber aggregates. The fiber
aggregates may be, for example, various fabrics, such as a woven
fabric, a knitted fabric, and a nonwoven fabric.
[0059] By removing the component B from the fiber aggregate, a
final product (i.e., a polyurethane elastomer fabric) suitable for
human body can be usually obtained.
[0060] For example, such a polyurethane elastomer fabric can be
obtained by a production method including a preparing step of
preparing a composite fiber as described above; a producing step of
producing a fabric comprising the composite fiber by using the
composite fiber; and a removing step of removing, from the fabric,
the component B to obtain a polyurethane elastomer fabric (a fabric
comprising a polyurethane elastomer monocomponent fiber).
[0061] It should be noted that the composite fiber fabric may
consist essentially of the composite fiber of the present
invention; or may be a woven, knitted or nonwoven fabric comprising
a part consisting essentially of the fiber of the present invention
(for example, a woven or knitted fabric comprising a fiber of the
present invention and another fiber other than the fiber of the
present invention such as a natural fiber, chemical fiber or
synthetic fiber; a woven or knitted fabric comprising a blended
yarn or a combined filament yarn comprising a fiber of the present
invention and another fiber other than the fiber of the present
invention; or a cotton-mixed nonwoven fabric). When the composite
fiber of the present invention is used in a combination with
another fiber in a woven, knitted or nonwoven fabric, the
proportion of the component A of the fiber in the woven fabric,
knitted fabric or nonwoven fabric may be, for example, 14% by mass
or more, preferably 15% by mass or more, preferably 18% by mass or
more, more preferably 23% by mass or more. When the composite fiber
of the present invention is used as a blended yarn or a combined
filament yarn, the proportion of the component A in this yearn may
be, for example, 14 to 95% by mass, and may be preferably 20% by
mass or more, preferably 30% by mass or more, more preferably 40%
by mass or more.
[0062] The polyurethane elastomer fabric obtained by removing the
component B from the composite fiber fabric by alkali treatment,
water treatment or some other treatment has a glass transition
temperature close to the temperature of the surface of human body
so as to be excellent in fitting during a dynamic movement of the
human body.
[0063] Moreover, the composite fiber according to the present
invention is advantageously used to produce a polyurethane
elastomer monocomponent fiber comprising a polyurethane elastomer
monocomponent fiber having a single fiber fineness in a range of,
for example, 0.3 to 50 dtex (preferably 0.3 to 40 dtex). When the
polyurethane elastomer monocomponent fiber having a small fineness
is desirable, the polyurethane elastomer monocomponent fiber may
have a small fineness of 0.3 to 10 dtex, preferably 0.3 to 5
dtex.
[0064] The composite fiber fabric or the polyurethane elastomer
fabric comprising the polyurethane elastomer monocomponent fiber
may be optionally subjected to a napping treatment, for example,
cloth-carding napping, or any other finishing treatment after the
process for producing the fabric.
[0065] It should be noted that the polyurethane elastomer fabric
may have a peak value of mechanical dynamic loss tangent (tan
.theta.) of, for example, 0.2 to 1.0 both inclusive, preferably 0.3
to 0.8 both inclusive, more preferably 0.4 to 0.7 both inclusive in
order for the fabric to have dynamic viscoelastic properties and
static viscoelastic properties comparable to those of human body
surface. As described above, such a fabric preferably contains the
component A in the specific proportion (for example, 14% by mass or
more).
EXAMPLES
[0066] Hereinafter, the present invention will be described in
detail by way of working examples. However, the present invention
is never limited by the examples. In the examples, the word
"part(s)" and the symbol "%" denote part(s) by mass and % by mass,
respectively, unless otherwise specified.
Example 1
[0067] As a component A was used a polyurethane elastomer named SMP
MM-3520 (manufactured by SMP Technologies Inc.; Tg of
35.+-.3.degree. C.; obtained by polymerizing a bifunctional
diisocyanate having a molecular weight of 160 to 310, a
bifunctional polyol having a molecular weight of 400 to 2000, and
1,4-butanediol diol at a molar ratio of 2.00 to 1.10:1.00:1.00 to
0.10 in a prepolymer manner). As a component B was used a
polyethylene terephthalate having an intrinsic viscosity [.eta.] of
0.52 and obtained by copolymerizing 8% by mass of a polyethylene
glycol having a molecular weight of 2000 and 5% by mole of sodium
5-sulfoisophthalate as copolymerizable components. The composite
ratio of the component A to the component B was set to a mass ratio
of 3:1, and these components were melted in different extruders,
respectively, and then the melted components were extruded from a
conjugate spinning nozzle (spinneret) to give composite filaments
each having a cross section shown in FIG. 1.
[0068] Next, the extruded filaments from the spinneret were
quenched with a transversely-blowing type cooling wind machine
having a length of 1.0 m, and continuously introduced into a tube
heater, 1.0 m in length and 30 mm in inner diameter (internal
temperature: 180.degree. C.) positioned directly downward from the
spinneret by 1.3 m, so as to be drawn inside the tube heater. An
oil was then applied to the drawn filaments from the tube heater,
and subsequently wound at a winding speed of 3000 m/minute by aid
of rollers to produce composite fibers of 111 dtex/24
filaments.
[0069] Thus obtained composite fiber was good in fiber making
processability and also knitting processability. A circular
knitting machine (28 gauges) was used to produce a circular knitted
fabric from the resultant composite fiber. This knitted fabric was
scoured, and then immersed in an aqueous alkali solution (liquid
temperature: 100.degree. C.) having a sodium hydroxide
concentration of 20 g/L at a bath ratio of 1:30 for 30 minutes so
as to dissolve the component B selectively to be removed from the
composite fiber fabric. The obtained knitted fabric made of
polyurethane elastomer monocomponent fibers gave a good wearing
feeling.
[0070] [Coverage Ratio of Component B in Fiber Cross Section]
[0071] From a photograph of a cross section of the fiber, 10
filaments were selected at random. The length of the
fiber-coverage-region of each of the filaments was measured to
calculate the percentage (coverage ratio) of the length of the
coverage-region based on the circumferential length in the fiber
cross section. The average of the respective coverage ratios of the
filaments was calculated out.
[0072] [Spinnability Evaluation]
[0073] The spinnability was evaluated in accordance with generation
status of fluffs and fiber breakage when 100 kg of the fiber
composition was spun to be wound, and was also evaluated in
accordance with generation status of fluffs and fiber breakage when
1 kg of the as-spun fibers were further unwound.
[0074] A: Fluffs and fiber breakage were not generated during fiber
spinning, as well as during fiber unwinding so that the
spinnability was good.
[0075] B: Fluffs and fiber breakage were not generated during fiber
spinning but were generated less than two times during fiber
unwinding so that the spinnability was good.
[0076] C: Fluffs and fiber breakage were generated less than two
times during fiber spinning, and were generated less than five
times during fiber unwinding.
[0077] D: Fluffs and fiber breakage were generated three or more
times during fiber spinning, and were generated six or more times
during fiber unwinding.
[0078] [Knitted Fabric Producibility Evaluation]
[0079] The knitted fabric producibility of the fiber was evaluated
in accordance with generation status of fluffs and fiber breakage
when 10 kg of the fiber was knitted.
[0080] A: Fluffs and fiber breakage were not generated so that this
property was good.
[0081] B: Fluffs and fiber breakage were generated less than two
times so that this property was good.
[0082] C: Fluffs and fiber breakage were generated two or more
times but less than five times.
[0083] D: Fluffs and fiber breakage were generated six or more
times
[0084] [Evaluation of Wearing Feeling]
[0085] Ten panelists each made a sensory evaluation about the
wearing feeling of the resultant knitted fabric. In the sensory
evaluation, each of the panelists evaluated the fabric by giving
two points, one point or zero point when the fabric was very good
in wearing feeling, was good in wearing feeling, or was poor in
wearing feeling, respectively. The total points thereof were
calculated to evaluate the wearing feeling.
[0086] A: The total points were 15 points or more.
[0087] B: The total points were 11 to 14 points.
[0088] C: The total points were 7 to 10 points.
[0089] D: The total points were 6 points or less.
Example 2
[0090] The same way as in Example 1 was performed except that the
ratio between the components A and B of the composite fiber was
changed as shown in Table 1, so as to produce a fiber and a knitted
fabric. The evaluations were performed.
[0091] The composite fiber was good in fiber making processability
and knitted fabric producing processability, and the resultant
knitted fabric was very good in wearing feeling.
Example 3
[0092] The same way as in Example 1 was performed except that
polylactic acid (6200D, manufactured by Cargill Dow LLC) was used
as the component B of the fiber, so as to produce a fiber and a
knitted fabric. The evaluations were performed.
[0093] The composite fiber was good in fiber making processability
and knitted fabric producing processability, and the resultant
knitted fabric was very good in wearing feeling.
Example 4
[0094] The same way as in Example 1 was performed to produce a
fiber and a knitted fabric except that the component B was changed
into a thermoplastic modified polyvinyl alcohol (manufactured by
Kuraray Co., Ltd.; saponification degree: 98.5, ethylene content:
8.0% by mole, and polymerization degree: 380) while using as the
component A the same polymer in Example 1, and that the spinning
oil was changed into a water-free oil composed of an antistatic
agent component and a lubricant component. Thereafter, the knitted
fabric was treated in hot water of 100.degree. C. at a bath ratio
of 1:30 for 40 minutes so as to dissolve the component B
selectively to be removed from the composite fiber fabric.
[0095] The composite fiber was good in fiber making processability
and knitted fabric producing processability. The obtained knitted
fabric made of polyurethane elastomer monocomponent fibers gave a
good wearing feeling.
Examples 5 to 6
[0096] The same way as in Example 1 was performed to produce each
of the fibers, and each of the knitted fabrics except that a
cross-sectional shapes of the fibers were changed as shown in Table
1 so as to make the evaluations.
[0097] In Examples 5 to 6, a non-circular nozzle was used as a
spinneret to produce the fiber.
[0098] Both of the examples showed the composite fiber good in
fiber making processability and knitted fabric producing
processability, and the obtained knitted fabric made of
polyurethane elastomer monocomponent fibers was very good in
wearing feeling.
TABLE-US-00001 TABLE 1 Outer-circumference Evaluation of coverage
ratio (%) of Knitted fabric feeling of worn Component A Component B
A/B Cross section component B Spinnability producibility fabric
Example 1 SMP MM-3520 Copolymerized 3/1 FIG. 1 100 A A A polyester
Example 2 SMP MM-3520 Copolymerized 4/1 FIG. 1 100 A A A polyester
Example 3 SMP MM-3520 Polylactic acid 3/1 FIG. 1 100 A A A Example
4 SMP MM-3520 Modified 3/1 FIG. 1 100 A A A polyvinyl alcohol
Example 5 SMP MM-3520 Copolymerized 3/1 FIG. 2 77 B B A polyester
Example 6 SMP MM-3520 Copolymerized 3/1 FIG. 3 100 A B B polyester
Comparative SMP MM-3520 -- -- Circular cross 0 D D D Example 1
section Comparative SMP MM-3520 -- -- Circular cross 0 D D D
Example 2 section Comparative SMP MM-3520 Copolymerized 1/1
Side-by-side 50 D D D Example 3 polyester Comparative SMP MM-3520
-- -- Circular cross 0 D D D Example 4 section Comparative SMP
MM-3520 -- -- Circular cross 0 D D D Example 5 section
Comparative Example 1
[0099] The same way as in Example 1 was performed except that the
component B shown in Table 1 was not used. The fiber making
processability was bad. The obtained knitted fabric made of
polyurethane elastomer monocomponent fibers was poor in wearing
feeling.
Comparative Example 2
[0100] The same way as in Example 1 was performed except that a
component A shown in Table 1 was used but no component B was used.
The fiber making processability was bad. The obtained knitted
fabric made of polyurethane elastomer monocomponent fibers was poor
in wearing feeling.
Comparative Example 3
[0101] The same way as in Example 1 was performed except that the
components A and B were conjugated into a side-by-side composite
fiber in which the component A constituted a core and the component
B covered 50% of the length of the entire circumference of the
component A in a cross section thereof. The resultant fiber was
poor in spinnability and knitted fabric producibility. The obtained
knitted fabric made of polyurethane elastomer monocomponent fibers
was poor in wearing feeling.
Comparative Example 4
[0102] The same way as in Example 1 was performed except that the
component B shown in Table 1 was not used. The fiber making
processability was bad. Furthermore, the obtained elastomer
monocomponent fibers were fed to an ordinary single covered yarn
producing machine in order to obtain a blended yarn in which each
of the elastomer monocomponent fibers was covered with a cotton
spun yarn 20/1. However, unwinding of the elastomer monocomponent
fibers was insufficiently attained by the adhesion of the fibers to
each other, so that the processability was bad. The obtained
knitted fabric made of blended yarns was poor in wearing
feeling.
Comparative Example 5
[0103] The same way as in Example 1 was performed except that the
component B shown in Table 1 was not used. The fiber making
processability was bad. Furthermore, the obtained elastomer
monocomponent fiber was fed to an ordinary single covered yarn
producing machine in order to obtain a blended yarn in which each
of the elastomer monocomponent fiber was covered with nylon 6
filaments 33T12. However, unwinding the elastomer monocomponent
fibers was insufficiently attained by the adhesion of the fibers to
each other, so that the processability was bad. The obtained
knitted fabric made of blended yarns was poor in wearing
feeling.
INDUSTRIAL APPLICABILITY
[0104] The composite fiber of the present invention can be used
mainly in a long (or continuous) fiber form or a short fiber form.
The composite fiber having a long fiber form can be used, alone or
as a part, to produce a woven or knitted fabric or the like
comprising polyurethane elastomer monocomponent fibers so as to be
made into a clothing material providing with a good wearing
feeling. This clothing material is suitably used for fields in
which a wearing feeling close to human skin is required as a
property for the material of underwear. The fiber may be, in a
short fiber form, used as staples for clothing, or used for dry
nonwoven fabric or wet nonwoven fabric, or for some other. The
fiber is high in flexibility in a range of 15 to 50.degree. C.,
preferably 15 to 45.degree. C., more preferably 15 to 35.degree.
C.; thus, the fiber is usable for not only clothing but also for
non-clothing, for example, for cleaning fabrics, materials for
filters, various residential materials, and industrial
materials.
[0105] As described above, the preferred embodiments of the present
invention have been described. However, referring to the present
specification, those skilled in the art would easily conceive
various changes and modifications from the embodiments within a
scope self-evident therefrom. Accordingly, such changes and
modifications are interpreted to fall within the scope of the
present invention, which is specified by the claims.
* * * * *