AU2016266265B2

AU2016266265B2 - Hygroscopic core-sheath conjugate yarn and production method therefor

Info

Publication number: AU2016266265B2
Application number: AU2016266265A
Authority: AU
Inventors: Tsuyoshi Hayashi; Kentaro Takagi; Daisuke Yoshioka
Original assignee: Toray Industries Inc
Current assignee: Toray Industries Inc
Priority date: 2015-05-22
Filing date: 2016-05-11
Publication date: 2020-01-30
Anticipated expiration: 2036-05-11
Also published as: EP3299500B1; WO2016190102A1; HK1246374A1; TWI693311B; KR102465144B1; CN107614765A; US20180148863A1; JP6090546B1; KR20180010185A; EP3299500A1; CA2986887A1; CN107614765B; JPWO2016190102A1; AU2016266265A1; TW201704571A; EP3299500A4

Description

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HYGROSCOPIC CORE-SHEATH CONJUGATE YARN AND PRODUCTION METHOD THEREFOR TECHNICAL FIELD

[0001]

The present invention relates to a hygroscopic core-sheath composite fiber

which is excellent in terms of feeling.

BACKGROUND ART

[0002]

Synthetic fibers including thermoplastic resins such as polyamides and

polyesters are excellent in terms of strength, chemical resistance, heat resistance, etc., and

are hence used extensively in clothing applications, industrial applications, etc.

[0003]

In particular, polyamide fibers not only have properties such as the peculiar

softness, high tensile strength, colorability by dyeing, and high heat resistance but also

have excellent hygroscopicity, and are hence in extensive use in applications such as inner

wear and sportswear. However, polyamide fibers are insufficient in hygroscopicity as

compared with natural fibers such as cotton, and have problems such as stuffiness and

stickiness. There is hence a problem in that the polyamide fibers are inferior in

comfortableness to natural fibers.

[0004]

Under such circumstances, a synthetic fiber which shows excellent moisture

absorbing/releasing properties for eliminating stuffiness and stickiness and has

comfortableness substantially comparable to that of natural fibers is desired mainly in

inner wear applications and sportswear applications.

[0005]

Methods in which a hydrophilic compound is added to polyamide fibers

have been most commonly investigated for that purpose. For example, Patent

Document 1 proposes a method in which polyvinylpyrrolidone is blended as a

hydrophilic polymer with a polyamide and the blend is spun to thereby improve the

hygroscopicity.

[0006]

Meanwhile, investigations are being made enthusiastically in which a fiber

is made to have a core-sheath structure in which a highly hygroscopic thermoplastic

resin is used as the core and a thermoplastic resin having excellent mechanical

properties is used as the sheath, thereby attaining both hygroscopicity and mechanical

properties.

[0007]

For example, Patent Document 2 describes a core-sheath composite fiber

which has a shape including a core and a sheath, the core being unexposed on the fiber

surface, in which the core is a polyether-block-amide copolymer including nylon-6 as a

hard segment, the sheath is a nylon-6 resin, and the areal proportion between the core

and the sheath in a fiber cross-section is 3/1 to 1/5.

[0008]

Patent Document 3 describes a core-sheath composite fiber including a

polyetheresteramide as the core and a polyamide as the sheath and having high

hygroscopicity, as a core-sheath type composite fiber having excellent hygroscopicity.

C:YnterwovenYNRPortblYDCCYANIIY9669646 .doc-I72020

This composite fiber is a core-sheath type composite fiber including a thermoplastic resin

as the core and a fiber-forming polyamide resin as the sheath, in which the main

component of the thermoplastic resin constituting the core is a polyetheresteramide and the

proportion of the core is 5-50% by weight of the overall weight of the composite fiber.

[0009]

Furthermore, Patent Document 4 describes a composite fiber having moisture

absorbing/releasing properties, which includes a polyamide or a polyester as a sheath

component and a water-absorbing thermoplastic resin including crosslinked poly(ethylene

oxide) as a core component. Described therein is a highly hygroscopic core-sheath

composite fiber including a highly hygroscopic water-insoluble modified poly(ethylene

oxide) disposed as the core and a polyamide disposed as the sheath.

BACKGROUND ART DOCUMENT PATENT DOCUMENT

[0010]

Patent Document 1: JP-A-9-188917

Patent Document 2: WO 2014/10709

Patent Document 3: JP-A-6-136618

Patent Document 4: JP-A-8-209450

[0011]

However, the fiber described in Patent Document 1 has a problem in that

although this fiber has moisture absorbing/releasing properties substantially comparable to

those of natural fibers, the performance is not fully satisfactory, and even higher moisture

absorbing/releasing properties are required to be attained.

C:YnterwovenYNRPortblYDCCYANIIY9669646 .doc-I72020

[0012]

Meanwhile, the core-sheath composite fibers of Patent Documents 2 to 4 have

moisture absorbing/releasing properties equal to or higher than those of natural fibers.

However, the core deteriorates due to repetitions of practical use, and there has been a

problem in that the hygroscopicity decreases with repetitions of use. In addition, fabrics

formed therefrom have softness equal to that of nylons and are hence insufficient in

feeling. A soft feeling superior to that of any existing article has been strongly desired.

SUMMARY OF THE INVENTION

[0013]

The present invention aims to provide a core-sheath composite fiber which

deals with the problems of the background-art techniques, and which may be capable of

attaining: comfortableness superior to that of natural fibers with high hygroscopicity;

laundering durability of the hygroscopicity, which makes the fiber withstand practical use;

and a soft feeling that has been impossible so far.

[0014]

Accordingly, the present invention includes the following configurations.

[0015]

(1) A hygroscopic core-sheath composite fiber which comprises: a

polyetheresteramide copolymer as a core polymer; and a polyamide as a sheath polymer,

and which has a degree of shrinkage with boiling water of 6-11%.

[0016]

(2) The hygroscopic core-sheath composite fiber according to (1), which has an

elongation of 60-90%.

[0017]

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(3) A false-twist textured yarn including the hygroscopic core-sheath composite

fiber according to (1) or (2).

[0018]

(4) A fabric at least a part of which includes the hygroscopic core-sheath

composite fiber according to (1) or (2).

[0019]

(5) A process for producing the hygroscopic core-sheath composite fiber according

to (1) or (2), the process including: ejecting a filament from a spinneret; cooling and

solidifying the ejected filament with a cooling wind; thereafter applying an aqueous

solution (oil emulsion) twice to the filament; and then winding up the filament,

in which a time gap between the first-stage application and the second-stage

application is 20 msec or longer.

[0020]

According to the present invention, it is possible to provide a core-sheath

composite fiber which can attain: comfortableness superior to that of natural fibers with

high hygroscopicity; laundering durability of the hygroscopicity, which makes the fiber

withstand practical use; and a soft feeling that has been impossible so far.

DETAILED DESCRIPTION OF THE INVENTION

[0021]

The core-sheath composite fiber of the present invention employs a

polyamide as the sheath and a thermoplastic polymer having high hygroscopicity as the

core. The term "thermoplastic polymer having high hygroscopicity as the core" means

a polymer which, when examined in a pellet form, has a AMR of 10% or higher, and

examples thereof include polyetheresteramide copolymers, poly(vinyl alcohol), and

cellulosic thermoplastic resins. Of these, a polyetheresteramide copolymer is used

from the standpoint that this polymer has satisfactory thermal stability and satisfactory

compatibility with the polyamide as the sheath and has excellent separation resistance.

By thus-configuring a core-sheath composite fiber, the fiber can be made to have a high

AMR, and a textile which has excellent hygroscopicity and is comfortable can be

achieved. AMR is an index to humidity regulation, and is expressed by the difference

in the coefficient of moisture absorption between an in-garment temperature and

humidity condition during light to medium works or light to medium exercises which is

represented by 30°Cx90O% RH and an outside-air temperature and humidity condition

represented by 20°Cx65% RH. The larger the AMR, the higher the hygroscopicity and

the better the comfortableness during wear.

[0022]

The polyetheresteramide copolymer is a block copolymer which has an

ether linkage, an ester linkage, and an amide linkage in the same molecular chain.

More specifically, the copolymer is a block copolymer obtained by subjecting a

polyamide ingredient (A) including one or more members selected from among lactams,

aminocarboxylic acids, and salts of diamines with dicarboxylic acids and a

polyetherester ingredient (B) including a dicarboxylic acid and a poly(alkylene oxide)

glycol to polycondensation reaction.

[0023]

Examples of the polyamide ingredient (A) include lactams such as

caprolactam, dodecanolactam, and undecanolactom, o-aminocarboxylic acids such as

aminocaproic acid, 11-aminoundecanoic acid and 12-aminododecanoic acid, and

diamine-dicarboxylic acid nylon salts which are precursors for nylon-66, nylon-610,

nylon-612, etc. A preferred polyamide-forming ingredient is c-caprolactam.

[0024]

The polyetherester ingredient (B) is an ingredient including a dicarboxylic

acid having 4-20 carbon atoms and a poly(alkylene oxide) glycol. Examples of the

dicarboxylic acid having 4-20 carbon atoms include aliphatic dicarboxylic acids such as

succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid and

dodecanedioic acid, aromatic dicarboxylic acids such as terephthalic acid, isophthalic

acid and 2,6-naphthalenedicarboxylic acid, and alicyclic dicarboxylic acids such as 1,4

cyclohexanedicaroxylic acid; one of these or a mixture of two or more thereof can be

used. Preferred dicarboxylic acids are adipic acid, sebacic acid, dodecanedioic acid,

terephthalic acid, and isophthalic acid. Examples of the poly(alkylene oxide) glycol

include polyethylene glycol, poly(1,2- and 1,3-propylene oxide) glycol,

poly(tetramethylene oxide) glycol, and poly(hexamethylene oxide) glycol. Preferred is

polyethylene glycol, which has especially satisfactory hygroscopicity.

[0025]

The number-average molecular weight of the poly(alkylene oxide) glycol is

preferably 300-10,000, more preferably 500-5,000. In cases when the molecular

weight of the poly(alkylene oxide) glycol is 300 or higher, this glycol is less apt to fly

off from the system during the polycondensation reaction and a fiber having stable

hygroscopicity is obtained. Such molecular weights are hence preferred. In cases

when the molecular weight thereof is 10,000 or less, an even block copolymer is

obtained to attain stable spinning. Such molecular weights are hence preferred.

[0026]

It is preferable that the proportion of the polyetherester ingredient (B) is 20

80% by mole. Proportions thereof not less than 20% are preferred because satisfactory

hygroscopicity is obtained. Meanwhile, proportions thereof not higher than 80% are

preferred because satisfactory color fastness and laundering durability are obtained.

[0027]

Commercial examples of such polyetheresteramide copolymer are "MH

1657" and "MV 1074", both manufactured by Arkema Inc.

[0028]

Examples of the polyamide as the sheath include nylon-6, nylon-66, nylon

46, nylon-9, nylon-610, nylon-11, nylon-12, nylon-612, and the like and copolyamides

including these nylons and comonomer components such as compounds having an

amide-forming functional group, e.g., laurolactam, sebacic acid, terephthalic acid,

isophthalic acid, and 5-sodiumsulfoisophthalic acid. Preferred of these are nylone-6,

nylon-11, nylon-12, nylon-610, and nylon-612, from the standpoint of spinning because

the difference in melting point between such nylons and the polyetheresteramide

copolymer is so small that the polyetheresteramide copolymer can be inhibited from

thermally deteriorating during melt spinning. Preferred of these is nylon-6, which has

excellentdyeability.

[0029]

Various additives may have been copolymerized with or incorporated into

the sheath polyamide in the present invention according to need in a total additive

content in the range of 0.001-10% by weight. Examples of the additives include a

delustering agent, flame retardant, antioxidant, ultraviolet absorber, infrared absorber,

nucleator, fluorescent brightener, antistatic agent, hygroscopic polymer, and carbon.

[0030]

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The core-sheath composite fiber of the present invention must have a degree

of shrinkage with boiling water of 7-11%. Also disclosed is a degree of shrinkage

with boiling water of 6-11%. By regulating the degree of shrinkage with boiling water

thereof so as to be within the specified range, a soft feeling which has not been attained

with any conventional nylon is rendered possible in cases when a false-twist textured

yarn is obtained from the core-sheath composite fiber and a textile is then obtained from

the yam. In case where the degree of shrinkage with boiling water thereof is less than

6%, this core-sheath composite fiber has undergone crystallization before false twisting

and, hence, cannot be crimped in false twisting, making it impossible to attain fluffiness

and a soft feeling. Meanwhile, in case where the degree of shrinkage with boiling

water thereof is higher than 11%, the shrinkage is so large that the textile may give a

hard feeling. A more preferred range of the degree of shrinkage with boiling water is

6-10%, and an even more preferred range thereof is 7-9.5%.

[0031]

From the standpoint of attaining a degree of shrinkage in boiling water of 6

11%, for example 7-11%, it is preferable that when producing the core-sheath

composite fiber described above, an oil is applied in two stages. Although an oil is

essential for improving the smoothness and collectibility of fibers, the degree of

shrinkage with boiling water can be easily reduced by applying an aqueous solution

(emulsion) to a filament which has been cooled and solidified and, after the lapse of a

certain time period, applying an emulsion again. This is thought to be because the

first-stage application simultaneously supplies water to the fiber and crystallization

proceeds thereupon, and the second-stage oil supply ensures smoothness and

collectibility. It is preferable that the time gap between the first-stage application and

the second-stage application is 20 msec or longer, because this time gap makes it easy

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to regulate the degree of shrinkage with boiling water so as to be within the specified

range according to the present invention. Although longer application time gaps are

preferred, the longer gaps

9A

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necessitate a prolongation of the step. It is therefore preferred to set a time gap while taking

account of efficient production. Incidentally, in cases when the spinning speed is 3,000 m/min

and the distance between the first-stage and second-stage oil application positions is 1.5 m,

then the application time gap is 30 msec. Furthermore, from the standpoint of regulating the

degree of shrinkage with boiling water so as to be within the specified range, it is preferable

that the tension of the fiber during the oil application is in the range of 0.15-0.40 cN/dtex,

because the orientation of the fiber is accelerated thereby. The fiber tension is measured at a

position between the first-stage and second-stage oil application positions. It is also preferable

that the core-sheath composite fiber of the present invention has an elongation of 60-90%. It

is desirable to false-twist the core-sheath composite fiber from the standpoint of improving the

softness, and an elongation of 60-90% is preferred for the false twisting because the crimp is

less apt to change with the lapse of time or less apt to be weakened by repeated stretching and

because the softness of the fiber can be further improved.

[0032]

The core-sheath composite fiber of the present invention is not particularly limited

in total fineness and the number of filaments (in the case of long fibers) and in length and the

number of crimp waves (in the case of short fibers), and can be made to have any desired

cross-sectional shape in accordance with the intended use of the fabric to be obtained, etc. In

view ofuse as a long-fiber material for clothing, it is preferable that the core-sheath composite

fiber of the present invention has, as a multifilament, a total fineness of 5-235 dtex and the

number of filaments of 2-144. The cross-sectional shape preferably is circular, triangular, flat,

Y-shaped, star-shaped, eccentric, or laminate-type.

[0033]

The proportion of the core in the core-sheath composite fiber of the present

invention is preferably 20-80 parts by weight, more preferably 30-70 parts by weight,

per 100 parts by weight of the composite fiber. By regulating the proportion thereof so

as to be within that range, not only a satisfactory AMR is obtained but also the

processability during false twisting is rendered satisfactory.

[0034]

Chips of the polyamide to be used as the sheath in the present invention

have a sulfuric-acid relative viscosity of preferably 2.3-3.3, more preferably 2.6-3.3.

By regulating the sulfuric-acid relative viscosity so as to be within that range, not only

the degree of shrinkage with boiling water can be easily regulated but also the

laundering durability of AMR is improved, easily rendering comfortable textiles

possible.

[0035]

It is preferable that chips of the polyetheresteramide copolymer to be used

as the core in the present invention have an o-chlorophenol relative viscosity (OCP

relative viscosity) of 1.2-2.0. In cases when the o-chlorophenol relative viscosity

thereof is 1.2 or higher, not only optimal stress is imposed on the sheath in spinning to

cause the crystallization of the sheath polyamide to proceed, thereby facilitating control

of the degree of shrinkage with boiling water, but also the laundering durability of AMR

improves. Such o-chlorophenol relative viscosities are hence preferred.

[0036]

Besides being produced by the preferred production process described

above, the core-sheath composite fiber of the present invention can be obtained by

known techniques of melt spinning or composite spinning. Examples thereof are as

follows.

[0037]

For example, a polyamide (sheath) and a polyetheresteramide copolymer

(core) are separately melted, and the melts are metered and transported with gear

pumps, then put together to form a composite flow by an ordinary method so as to result

in a core-sheath structure, and ejected from a spinneret. A cooling wind is blown

against the resultant filament with a filament cooler, such as a chimney, thereby cooling

the filament to room temperature. In this method, an oil is supplied in two stages, and

the oiled filament is passed through take-up rollers. The peripheral speed of the take

up rollers is preferably 3,000-3,900 m/min. The filament which has passed through

the take-up rollers is stretched preferably in a stretch ratio of 1.0-1.1 and is passed

through the stretching rollers. Thereafter, the winder (winding device) is regulated so

as to impose a winding tension which results in a preferred package form, and the

filament is then wound up therewith.

[0038]

By false-twisting the core-sheath composite fiber obtained by the present

invention, the softness thereof is improved and a feeling which has not been attained so

far is obtained. The false twisting can be conducted using a known technique such as

friction processing, pin processing, or belt nip processing. When cost, etc. are taken

into account, friction processing is preferred. When crimping performance is taken

into account, pin processing is preferred. In any processing, it is preferred to set the

elongation of the false-twisted textured yarn at 25-40%, when the change of the crimp

with the lapse of time, processability in the false twisting, and the subsequent weaving

or knitting are taken into account. It is preferred to perform heat setting at 140-170°C

in order to obtain satisfactory crimp and to inhibit the crimp from changing with the

lapse of time.

[0039]

The core-sheath composite fiber of the present invention is advantageously

used in fabric and garments. With respect to the type of fabric, it is possible to select

woven fabric, knitted fabric, nonwoven fabric, etc. according to purposes, and clothing

is also included. The garments can be various clothing products including inner wear

and sportswear.

EXAMPLES

[0040]

The present invention will be explained below in more detail by reference to

Examples. In the Examples, property values were determined by the following

methods.

[0041]

(1) Sulfuric-acid Relative Viscosity

A 0.25-g portion of a sample was dissolved in sulfuric acid having a

concentration of 98% by weight, so that the sample amount was 1 g per 100 mL of the

sulfuric acid. Using an Ostwald viscometer, the solution was examined for flow time

(TI) at 25°C. Subsequently, the sulfuric acid having a concentration of 98% by weight

was examined alone for flow time (T2). The ratio of TI to T2, i.e., T1/T2, was taken

as the sulfuric-acid relative viscosity.

[0042]

(2) o-Chlorophenol Relative Viscosity (OCP relative viscosity)

A 0.5-g portion of a sample was dissolved in o-chlorophenol so that the

sample amount was 1 g per 100 mL of the o-chlorophenol. Using an Ostwald

viscometer, the solution was examined for flow time (TI) at 25°C. Subsequently, the

o-chlorophenol was examined alone for flow time (T2). The ratio of TI to T2, i.e.,

TI/T2, was taken as the OCP relative viscosity.

[0043]

(3) Fineness

A fiber sample was set on a counter reel having a peripheral length of 1.125

m, and the counter reel was caused to make 200 revolutions to form a hank in a loop

form. The hank was dried in a hot-air drying oven (105±2°C x 60 min) and then

weighed with a balance. The measured mass was multiplied by an official moisture

regain, and the fineness was calculated from the resultant product. The official

moisture regain of the core-sheath composite fiber was taken as 4.5% by weight.

[0044]

(4) Strength and Elongation

A fiber sample was examined with "TENSILON" (registered trademark)

UCT-100, manufactured by Orientec Co., Ltd., under the constant-speed stretching

conditions shown in JIS L1013 (Test Methods for Chemical-Fiber Filament Yams,

2010). The elongation was determined from the tensile strength/elongation curve by

obtaining the elongation at the point on the curve where a maximum strength was

observed. Meanwhile, a value obtained by dividing the maximum strength by the

fineness was taken as the strength. The measurement was made ten times, and average

values were taken as the strength and the elongation.

[0045]

(5) Degree of Shrinkage with Boiling Water

A hank of a fiber was taken, and the sample length SO was measured under

a load of 0.09 cN/dtex. Thereafter, the hank under no load was treated by immersion

in boiling water for 15 minutes. After the treatment, the hank was air-dried and the

sample length Sl was measured under a load of 0.09 cN/dtex. The degree of shrinkage

with boiling water was calculated using the following equation.

Degree of shrinkage with boiling water = (SO-S1)/S0x100% (1)

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[0046]

(6) Recovery of Stretchability (CR)

The recovery of stretchability is an index to the crimp properties of false-twisted

textured yams.

[0047]

A hank of a false-twisted texture yam was taken, and was subjected, in a free state,

to a 20-minute treatment with 90°C water and then air-dried. Subsequently, in 25°C water, a

load of 0.0018 cN/dtex was imposed on the hank, and the hank length LI was measured at 2

minutes thereafter. Next, in the same water, the load of 0.0018 cN/dtex was removed and a

load of 0.09 cN/dtex was imposed on the hank, and the hank length LO was measured at 2

minutes thereafter. The recovery of stretchability was calculated using the following equation.

CR=(LO-L1)/LOx100O% (2)

[0048]

(7) AMR

Using a circular knitting machine, a cylindrical knitted fabric was produced so as

to result in a stitch density of 50. In the case of fibers having a low fineness based on

corrected weight, the fibers were suitably put together so that the fibers being supplied to the

circular knitting machine had a total fineness of 50-100 dtex. Inthe case of ayarnhaving a

total fineness exceeding 100 dtex, a single yarn was supplied to the circular knitting machine

and knitted so as to result in a stitch density of 50 as in the case shown above. An about 1-2 g

portion of the cylindrical knitted fabric was weighed out and introduced into a weighing

bottle, dried by holding it at 110°C for 2 hours, and then weighed (WO). Next, the specimen

being examined was held at 20°C and a relative humidity of 65% for 24 hours and then

weighed (W65). Furthermore, this specimen was held at 30°C and a relative humidity of90%

for 24 hours and then weighed (W90). AMR was calculated using the following equations.

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MR1 = [(W65-W0)/W0]x 100% (3)

MR2= [(W90-W0)/W0]x100% (4)

AMR = MR2-MR1 (5)

[0049]

(8) AMR after Laundering

The cylindrical knitted fabric was repeatedly laundered 20 times by the method

No. 103 described in JIS L0217 (1995), appended table 1. Thereafter, this fabric was

examined to calculate the AMR (moisture absorbing/releasing properties) in the manner

described above.

Fabrics having a AMR of 7.0% or larger were rated as S, and fabrics having a

AMR of 5.0% or larger and less than 7 .0% were rated as A.

[0050]

(9) Retention of AMR after Laundering

The retention of AMR after laundering was calculated as an index to a change in

AMR through laundering, using the following equation.

[(AMR after laundering)/( AMR before laundering)]x100 (6)

Fabrics having a retention of AMR of 95% or higher were rated as S, and fabrics

which had a retention of AMR of 90% or higher and less than 95% and had laundering

durability and which were regarded as giving satisfactory comfortableness during wear were

rated as A. The others were rated as C.

[0051]

(10) Feeling of Fabric

A core-sheath composite fiber of the present invention and a 22-dtex elastic

polyurethane fiber were used to produce a bare plain knitted fabric using a 28G single circular knitting machine, and the knitted fabric was subjected to scouring, heat setting, dyeing, and finish setting to obtain a fabric. Meanwhile, an ordinary, nylon-6, 44-dtex, 26-filament, false-twist textured yam (CR, 26%) was prepared, and a bare plain knitted fabric was produced therefrom in the same manner as described above. The fabrics obtained were evaluated for feeling and compared. S and A were acceptable.

S ... Far softer than the ordinary fabric formed using nylon-6.

A ... Superior in softness to the ordinary fabric formed using nylon-6.

C ... Equal to the ordinary fabric formed using nylon-6.

[0052]

(11) Overall Evaluation

In the case where all of the AMR after laundering, retention of AMR after

laundering, and feeling of fabric were rated as S, the fabric not only had

comfortableness with satisfactory moisture absorbing properties but also had excellent

softness; the overall evaluation in this case was S. In the case where all these

properties were rated as A or higher, the overall evaluation was A. In the case where

any of those properties was rated as C, the overall evaluation was C.

[0053]

(12) Tension Measurement

Tension values were measured using TENSION METER and FT-R pickup

sensor, both manufactured by Toray Engineering Co., Ltd.

[0054]

With respect to fiber tension at the time of first-stage oil application, the

value of tension was measured between the first-stage and second-stage oil application

devices, and the tension value was divided by the fineness. The resultant quotient

(cN/dtex) was taken as the fiber tension.

[0055]

Winding tension was determined by measuring the tension value (cN)

between the second roller and the winder.

[0056]

[Example 1]

A polyetheresteramide copolymer (MH 1657, manufactured by Arkema

Inc.; o-chlorophenol relative viscosity, 1.69) including nylon-6 as a polyamide

component and polyethylene glycol having a molecular weight of 1,500 as a polyether

component (poly(alkylene oxide)glycol) in which the proportion of the polyether

component was about 76% by mole was used for the core, and nylon-6 having a

sulfuric-acid relative viscosity of 2.71 and a terminal amino group content of 5.95x10-5

mol/g was used for the sheath. The polyetheresteramide copolymer and the nylon-6

were melted at 270°C and spun with a spinneret for concentric core-sheath formation so

as to result in a core-sheath ratio (parts by weight) of 50/50. The terminal amino group

content had been regulated with hexamethylenediamine and acetic acid during the

polymerization.

[0057]

During the spinning, the rotational speeds of the gear pumps were set so as

to give core-sheath composite fibers having a total fineness of 57 dtex, and the core

ingredient and the sheath ingredient were each ejected at a rate of 19.6 g/min. The

filaments ejected from the spinneret nozzle were cooled and solidified with a filament

cooler, and were then subjected to first-stage oil application in which an oil emulsion

having a concentration of 1% was applied thereto with an oiling device. The tension

of the fibers at this moment was 0.30 cN/dtex. A second-stage oiling device was

disposed at a position 2.0 m downstream from the first-stage oiling, and an oil emulsion

having a concentration of 15% was used to conduct oil application. Thereafter, the

fibers were temporarily taken up by a first roller which was rotating at a speed of 3,500 m/min, and were subsequently wound up, via a second roller which was rotating at the same speed, by a winder having a peripheral speed regulated to 3,430 m/min so as to result in a winding tension of 5 cN. In this case, the time gap between the first-stage oil application and the second-stage oil application was 34 msec. The core-sheath composite fibers obtained had the properties shown in Table 1. Thus, core-sheath composite fibers having a degree of shrinkage with boiling water of 8.5% and an elongation of 75% were obtained.

[0058]

Using a friction type false-twist texturing machine, the core-sheath

composite fibers were processed under the conditions of a processing ratio of 1.3,

processing speed of 400 m/min, and heater temperature 150°C, thereby obtaining a 44

dtex, 26-filament, false-twist textured yarn having an elongation of 34%. These false

twisting conditions were common among the Examples and the Comparative Examples.

[0059]

The false-twist textured yarn obtained was evaluated and, as a result, was

found to have a AMR of 12.1% and a AMR after laundering of 11.8%, that is, the

retention of AMR was 98%. The yarn showed highly satisfactory moisture

absorbing/releasing properties, and the moisture absorbing/releasing properties had

highly satisfactory laundering durability. The fabric showed an excellent feeling and

was superior in softness to the ordinary nylon. Consequently, the overall evaluation

was S.

[0060]

[Example 2]

The speeds of the first roller and second roller were regulated to 3,200

m/min, and spinning was conducted using the same positional relationship between the

first stage and the second stage as in Example 1, i.e., 2.0 m. Namely, spinning was

Il:\Kzh\nterwovn\NRPortbl\DCC\KZIlf6270806_I.docx-I00/2018

- 20

conducted in which the oil application time gap was 38 msec. Incidentally, the speed of the

winder was regulated so as to result in a winding tension of 5 cN, as in Example 1. The

polymer ejection rates were regulated so as to give a false-twist textured yarn having a

fineness of 44 dtex. The core-sheath composite fibers obtained had the properties shown in

Table 1. The degree of shrinkage with boiling water was 7.2%, and the elongation was 81%.

[0061]

False twisting was conducted in the same manner as in Example 1, except that the

processing ratio was regulated to 1.35 so as to give a false-twist textured yam having an

elongation of 35%. Thus, a 44-dtex, 26-filament, false-twist textured yarn was obtained.

[0062]

The false-twist textured yarn obtained had a AMR after laundering of 11.2% and a

retention of AMR of 97%. The yam showed highly satisfactory moisture absorbing/releasing

properties, and the moisture absorbing/releasing properties had highly satisfactory laundering

durability. The fabric showed an excellent feeling and was superior in softness to the ordinary

nylon. Consequently, the overall evaluation was S.

[0063]

[Example 3]

The stretch ratio was regulated to 1.05. Namely, the speeds of the first roller and

the second roller were regulated to 3,500 m/min and 3,675 m/min, respectively, to conduct

spinning. The oil application time gap was the same as in Example 1, and the other conditions

were set from the same standpoint as in Example 1. The core-sheath composite fibers

obtained had the properties shown in Table 1. The degree of shrinkage with boiling water was

9.5%, and the elongation was 66%.

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False twisting was conducted in the same manner as in Example 1, except that the processing

ratio was regulated so as to give a false-twist textured yarn having an elongation of 35%.

Thus, a 44-dtex, 26-filament, false-twist textured yarn was obtained.

[0064]

The false-twist textured yarn obtained had a AMR after laundering of 12.8% and

a retention of AMR of 98%. The yarn showed highly satisfactory moisture

absorbing/releasing properties, and the moisture absorbing/releasing properties had highly

satisfactory laundering durability. Meanwhile, the feeling of the fabric was slightly rough

and hard because the degree of shrinkage with boiling water of the core-sheath composite

fibers was higher than that in Example 1. However, the fabric showed better softness than

the fabric obtained using ordinary nylon-6. Consequently, the overall evaluation was A.

[0065]

(This paragraph is intentionally left blank)

[0066]

(This paragraph is intentionally left blank)

[0067]

(This paragraph is intentionally left blank)

[0068]

[Example 5]

The procedure was changed so that the core-sheath ratio (parts by weight) was

20/80, the speeds of the first roller and the second roller were 3,800 m/min each, and the

second-stage oil application was conducted at a position 1.25 m downstream from the first

stage oil application. Namely, spinning was conducted in which the oil application time gap

was 20 msec. The core-sheath composite fibers obtained had the properties shown in Table

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- 22

1. The degree of shrinkage with boiling water was 10.8%, which was slightly high because

the time gap had been set at a shorter period. The elongation was 58%.

[0069]

False twisting was conducted in the same manner as in Example 1, except that

the processing ratio was regulated so as to give a false-twist textured yarn having an

[0070]

The false-twist textured yarn obtained had a AMR after laundering of 5.9%

and a retention of AMR of 98%. The yarn showed satisfactory moisture

highly satisfactory laundering durability. Meanwhile, the feeling of the fabric was

slightly rough and hard because the degree of shrinkage with boiling water of the core

sheath composite fibers was higher than that in Example 1. However, the fabric

showed better softness than the fabric obtained using ordinary nylon-6. Consequently,

the overall evaluation was A.

[0071]

[Example 6]

Spinning was conducted in the same manner as in Example 1, except that

nylon-6 having a sulfuric-acid relative viscosity of 3.30 and a terminal amino group

content of 4.78x10-5 mol/g was used for the sheath. The core-sheath composite fibers

obtained had the properties shown in Table 1. The degree of shrinkage with boiling

water was 9.3%, and the elongation was 70%.

[0072]

False twisting was conducted in the same manner as in Example 1, except

that the processing ratio was regulated so as to give a false-twist textured yarn having an

elongation of 35%. Thus, a 44-dtex, 26-filament, false-twist textured yarn was

obtained.

[0073]

The false-twist textured yarn obtained had a AMR after laundering of 12.2%

and a retention of AMR of 99%. The yarn showed highly satisfactory moisture

C:\Interwovn\NRPortbl\DCC\KZIIl\9003526 _.docx-2307/2019

- 24

was superior in softness to the ordinary nylon. Consequently, the overall evaluation was S.

[0074]

(This paragraph is intentionally left blank)

[0075]

(This paragraph is intentionally left blank)

[0076] (This paragraph is intentionally left blank)

[0077]

[Comparative Example 1]

Spinning was conducted in which nylon-6 having a sulfuric-acid relative

viscosity of 2.15 and a terminal amino group content of 4.70x10-5 mol/g was used for

the sheath, the speeds of the first roller and second roller were regulated to 4,000

m/min, and the positional relationship between the first stage and the second stage was

the same as in Example 1, i.e., 2.0 m. Namely, spinning was conducted in which the

oil application time gap was 30 msec. The core-sheath composite fibers obtained had

the properties shown in Table 2. The degree of shrinkage with boiling water was

11.5%, and the elongation was 68%.

[0078]

False twisting was conducted in the same manner as in Example 1, except

that the processing ratio was set so as to give a false-twist textured yam having an

elongation of 35%. Thus, a 44-dtex, 26-filament, false-twist textured yarn was

obtained.

[0079]

The false-twist textured yarn obtained had a AMR after laundering of 7.5%

and a retention of AMR of 70%. This yarn was poor in the laundering durability of

moisture absorbing/releasing properties. The feeling of the fabric was considerably

rough and hard because the degree of shrinkage with boiling water was higher than

those in the Examples. The fabric obtained was nothing but one which was equal in

feeling to the fabric obtained using ordinary nylon-6. Consequently, the overall

evaluation was C.

[0080]

[Comparative Example 2]

Spinning was conducted in which the speeds of the first roller and second

roller were regulated to 4,200 m/min, and the positional relationship between the first

stage and the second stage was the same as in Example 1, i.e., 2.0 m. Namely, spinning was conducted in which the oil application time gap was 7 msec. The core

sheath composite fibers obtained had the properties shown in Table 2. The degree of

shrinkage with boiling water was 14.5%, and the elongation was 70%.

[0081]

False twisting was conducted in the same manner as in Example 1, except

elongation of 35%. Thus, a 44-dtex, 26-filament, false-twist textured yarn was

obtained.

[0082]

The false-twist textured yarn obtained had a AMR after laundering of 10.6%

and a retention of AMR of 96%. This yarn showed highly satisfactory moisture

considerably rough and hard because the degree of shrinkage with boiling water was

higher than those in the Examples. The fabric obtained was nothing but one which

was equal in feeling to the fabric obtained using ordinary nylon-6. The feeling was

rated as C. Consequently, the overall evaluation was C.

[0083]

[Comparative Example 3]

Spinning was conducted in the same manner as in Example 1, except that

the speed of the second roller was changed to 3,465 m/min and the surface temperature

of the second roller was changed to 130°C. The core-sheath composite fibers obtained had the properties shown in Table 2. The degree of shrinkage with boiling water was

5.2%, and the elongation was 70%.

[0084]

False twisting was conducted in the same manner as in Example 1, except

elongation of 35%. Thus, a 44-dtex, 26-filament, false-twist textured yarn was

obtained.

[0085]

The false-twist textured yarn obtained had a AMR after laundering of 11.5%

and a retention of AMR of 96%. This yarn showed highly satisfactory moisture

highly satisfactory laundering durability. Meanwhile, with respect to the feeling of the

fabric, the false-twist textured yam had not been crimped because the degree of

shrinkage with boiling water had been higher than those in the Examples and because

the crystallization of the core-sheath composite fibers had proceeded. The fabric

obtained was poor in fluffiness and was nothing but one which was equal in feeling to

the fabric obtained using ordinary nylon-6. Consequently, the overall evaluation was

C.

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C:YlnterovenYNRPortblYDCCYANIIY9669646_l.doc-I/7/2020

INDUSTRIAL APPLICABILITY

[0088]

According to the core-sheath composite fiber of the present invention, high

hygroscopicity, laundering durability of the hygroscopicity, which makes the fiber

withstand practical use, and a soft feeling can be attained.

[0089]

The reference in this specification to any prior publication (or information

derived from it), or to any matter which is known, is not, and should not be taken as an

acknowledgment or admission or any form of suggestion that that prior publication (or

information derived from it) or known matter forms part of the common general

knowledge in the field of endeavour to which this specification relates.

[0090]

Throughout this specification and the claims which follow, unless the

context requires otherwise, the word "comprise", and variations such as "comprises" and

"comprising", will be understood to imply the inclusion of a stated integer or step or

group of integers or steps but not the exclusion of any other integer or step or group of

integers or steps.

Claims

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-31

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

[Claim 1]

A hygroscopic core-sheath composite fiber which comprises: a

polyetheresteramide copolymer as a core polymer; and a polyamide having a sulfuric-acid

relative viscosity of 2.6-3.3 as a sheath polymer, and which has a degree of shrinkage with

boiling water of 7-11%.
[Claim 2]

The hygroscopic core-sheath composite fiber according to claim 1, which has an

elongation of 60-90%.
[Claim 3]

A false-twist textured yarn comprising the hygroscopic core-sheath composite

fiber according to claim 1 or 2.
[Claim 4]

A fabric at least a part of which comprises the hygroscopic core-sheath

composite fiber according to claim 1 or 2.
[Claim 5]

A process for producing the hygroscopic core-sheath composite fiber according

to claim 1 or 2, the process comprising: ejecting a filament from a spinneret; cooling and

solidifying the ejected filament with a cooling wind; thereafter applying an aqueous solution

(oil emulsion) twice to the filament; and then winding up the filament,

wherein a time gap between thefirst-stage application and the second-stage

application is 20 msec or longer.