JPH10325020A - Composite fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composite fiber consisting of an ethylene-vinyl alcohol- based copolymer and a specific polyester block copolymer and capable of giving a woven or knitted fabric, excellent in gentle skin touch feeling, elasticity and softness, and fitting to the movement of a body. SOLUTION: This composite fiber is composed of an ethylene-vinyl alcohol- based copolymer and a polyester block copolymer, in which the later consists of (A) an aromatic polyester segment composed of dicarboxylic acid units and diol units of which >=70 mol.% dicarboxylic acid unit is an aromatic dicarboxylic acid unit and >=70 mol.% diol units is a 2-4C aliphatic α,ω-diol units, etc., and (B) an aliphatic polyester segment composed of dicarboxylic acid units and diol units or an aliphatic polyester segment composed of hydroxycarboxylic acid units, etc., and has a weight ratio of the components A/B=(95/5)-(30/70).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conjugate fiber capable of providing a woven or knitted fabric which is excellent in elasticity and flexibility, and which is very fit to the movement of the body, with a soft touch.

[0002]

2. Description of the Related Art The comfort of fabrics such as woven and knitted fabrics is closely related to moisture absorption, and at present, fabrics made of polyester fibers having poor moisture absorption are limited in application fields.
In particular, it has been extremely difficult to develop applications in the inner field. Therefore, in order to give moisture absorption to polyester fiber,
Numerous proposals have been made. For example, a fiber obtained by adding a polyalkylene glycol to polyester at a stage before spinning (Japanese Patent Publication No. 39-5214), a polyester fiber having a polyether segment copolymerized with a sulfonic acid group or a sulfonic acid salt (JP-A-59-106
157), but have not yet been put to practical use. In addition, in these proposals of imparting hygroscopicity, the level of hygroscopicity is low and has not reached a satisfactory level.

On the other hand, there has been proposed a method in which two kinds of polymers having different shrinkage properties are compound-spun into side-by-side type and eccentric core-sheath type in order to impart flexibility and high stretch-back property to the fabric, thereby exhibiting crimping performance. Have been. For example,
Japanese Patent Publication No. Sho 60-1404 discloses an elastic block polyetherester containing an inelastic polyester containing polybutylene phthalate as a main component and poly (tetramethylene oxide) glycol as a soft component. . However, these proposals aim at imparting crimpability to the fiber to impart flexibility to the fabric, and there is no hope for moisture absorption.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a conjugate fiber having hygroscopicity and excellent flexibility and elastic recovery.

[0005]

The above object is achieved by providing a composite fiber comprising an ethylene-vinyl alcohol copolymer and a polyester block copolymer. That is, a polyester block copolymer comprising an aromatic polyester segment (A) and an aliphatic polyester segment and / or an aliphatic polyether segment (B) is used as the polyester block copolymer, and ethylene-vinyl alcohol is used. It is a fiber that is composited with a system copolymer.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the ethylene-vinyl alcohol copolymer according to the present invention will be described. The ethylene-vinyl alcohol-based copolymer used in the present invention is a saponified ethylene-vinyl acetate-based copolymer. The amount of ethylene contained in the copolymer is preferably 25 to 70 mol%, more preferably 30 to 50 mol%. If the ethylene content of the copolymer is high, that is, if the content of the vinyl alcohol portion is low, the properties such as hydrophilicity are naturally lowered due to the reduction of hydroxyl groups, and the intended hydrophilicity, hygroscopicity, Effects such as water absorption tend to decrease. On the other hand, if the content of the vinyl alcohol portion is too high from the viewpoint of the spinning properties, the melt spinnability will decrease in the compounding with the polyester block copolymer described below, and the spinnability will deteriorate, and the single yarn It leads to cutting and thread breakage.

Further, in the present invention, the ethylene-vinyl alcohol copolymer is produced by saponifying an ethylene-vinyl acetate copolymer with sodium hydroxide, and the degree of saponification is 95% or more. Is preferred. If the saponification degree is too low, not only the crystallinity of the copolymer is reduced and the fiber basic physical properties such as strength are reduced, but also the copolymer is easily softened, causing trouble in the processing step. In addition, the texture of the obtained fiber or fiber product may be deteriorated.

[0008] The copolymer can be produced by a known method. For example, ethylene and vinyl acetate are radically polymerized in a polymerization solvent such as methanol in the presence of a radical polymerization catalyst, then unreacted monomers are expelled, and a saponification reaction is caused by sodium hydroxide to produce ethylene-vinyl alcohol. After being made into a system copolymer, it is pelletized in water, washed with water and dried. In the process, an alkali metal or an alkaline earth metal is easily intervened in the copolymer, and its amount is several hundred ppm or more. When these metal ions are present, the copolymer is liable to be thermally decomposed. Therefore, it is necessary to reduce the amount to 100 ppm or less, particularly 50 ppm or less. As a method for reducing such metal ions, a method in which the wet pellets in the above-described production process are washed with a large amount of pure aqueous solution containing acetic acid, and further washed with only a large excess of pure water.

Such ethylene-vinyl alcohol-based copolymer has a melting point of about 150 to 180 ° C., and in hot water, the melting point actually decreases, and even at 150 ° C. or lower, it is easily softened. Therefore, at a composite spinning temperature with the polyester block copolymer, for example, 240 to 290 ° C., the copolymer is easily softened. Therefore, if the area of the copolymer exposed to the fiber surface is large, the copolymer may soften depending on the processing conditions, leading to a sticking phenomenon between the fibers. In order to suppress the hardness of the feeling due to the sticking phenomenon, the copolymer is subjected to acetalization treatment with aldehydes such as formaldehyde and glutaraldehyde, and acetalized dialdehyde to give hot water resistance. It is preferable to form a composite with a polyester block copolymer. Further, since the ethylene-vinyl alcohol copolymer easily gels at the time of spinning at a high temperature, it is preferable to add an antioxidant to suppress gelation.

Next, the polyester block copolymer will be described. The polyester block copolymer comprises an aromatic polyester segment (A) and an aliphatic polyester segment and / or an aliphatic polyether segment (B), wherein (a) the aromatic polyester segment (A) is a dicarboxylic acid Units and diol units.
At least 70% by mole of the aromatic dicarboxylic acid unit and at least 70% by mole of the diol unit are aliphatic α, ω-diol units having 2 to 4 carbon atoms and 1,4-cyclohexanedimethanol-unit. (B) an aliphatic polyester segment and / or an aliphatic polyether segment (B) mainly comprising a dicarboxylic acid unit and a diol unit. A polyester segment (B1), at least one of an aliphatic polyester segment (B2) mainly composed of hydroxycarboxylic acid units and an aliphatic polyether segment (B3) mainly composed of poly (alkylene oxide) glycol units. Has features.

In the aromatic polyester segment (A) constituting the copolymer, the proportion of aromatic dicarboxylic acid units is less than 70 mol% based on the total dicarboxylic acid units constituting the aromatic polyester segment (A). If this is the case, the heat resistance of the polyester block copolymer is reduced, so that a polyester block copolymer having good physical properties cannot be obtained, and thus a conjugate fiber containing the polyester block copolymer as one component is melt-spun. Is difficult to do. In order to improve the heat resistance of the polyester block copolymer and satisfactorily melt-spin a conjugate fiber comprising the copolymer as a component, at least 80 mol% of the dicarboxylic acid units are aromatic dicarboxylic acid units. It is more preferable that 90 mol% or more is an aromatic dicarboxylic acid unit.

The aromatic dicarboxylic acid unit includes
Any aromatic dicarboxylic acid unit derived from an aromatic dicarboxylic acid having a molecular weight of 400 or less may be used, and is not particularly limited. Specifically, derived from aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, biphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, diphenyl ketone dicarboxylic acid, and sodium sulfoisophthalate. Units to be used. These aromatic dicarboxylic acids may be used alone or in combination of two or more. The above-mentioned aromatic polyester segment (A) may contain, if necessary, other dicarboxylic acid units of less than 30 mol%, preferably 20 mol% or less, more preferably 10 mol% or less, for example, 1,4-cyclohexanedicarboxylic acid. Alicyclic dicarboxylic acid units such as units,
One or more aliphatic dicarboxylic acid units composed of aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, azelaic acid and sebacic acid may be used in combination.

Further, in the aromatic polyester segment (A), an aliphatic α, ω-di-
And at least one diol unit selected from 1,4-cyclohexanedimethanol units is 70 moles based on all diol units constituting the aromatic polyester segment (A). %, The heat resistance of the polyester block copolymer decreases, and the fibrillation processability decreases due to agglomeration between single yarns during spinning of the conjugate fiber and deterioration of the melt viscosity balance during spinning. Become. In this respect, the aliphatic α having 2 to 4 carbon atoms,
The ratio of at least one diol unit selected from the ω-diol unit and the 1,4-cyclohexanedimethanol unit is 80 mol of the total diol unit constituting the aromatic polyester segment (A). %, Preferably 90% by mole or more.

The aliphatic α, ω-diol unit having 2 to 4 carbon atoms is a unit composed of 1,4-butanediol, 1,3-propanediol, and 1,2-ethylene glycol. Can be mentioned. The aromatic polyester segment (A) may have only one of these diol units and 1,4-cyclohexanedimethanol unit, or may have two or more thereof.

Further, if necessary, the aromatic polyester segment (A) is less than 30 mol%, preferably 2 mol%.
0 mol% or less, more preferably 10 mol% or less of other diol units such as 1,5-pentanediole, 1,1
6-hexanediol, neopentyl glycol, 3-
Methyl-1,5-pentaneddiol, 2-methyl-1,
8-octanediol, 1,9-nonanediol, 1,1
Aliphatic diols such as cyclohexanediol; aromatic diols such as 1,4-bis (β-hydroxyethoxy) benzene and p-xylene glycol One or more diol units such as diols may be used in combination. If the amount of the aromatic polyester segment (A) is small, a polyhydric alcohol such as trimethylolethane, trimethylolpropane, glycerin, 1,2-hexanetriol or pentaerythritol may be used, if necessary. May be included.

As a specific example of the aromatic polyester segment (A), poly (tetramethylene terephthalate)
Segment, poly (tetramethylene-2,6-naphthalenedicarboxylate) segment and poly (1,4
-Cyclohexane dimethylene terephthalate) segment and the like, and these are preferable from the viewpoint of improving heat resistance and spinnability of the polyester block copolymer.

In the copolymer, the aliphatic polyester segment and / or aliphatic polyether segment (B) is composed of an aliphatic polyester segment (B1) mainly composed of dicarboxylic acid units and diol units, It is also characterized by comprising at least one of an aliphatic polyester segment (B2) mainly composed of carboxylic acid units and an aliphatic polyether segment (B3) mainly composed of poly (alkylene oxide) glycol units.

The aliphatic polyester segment (B1) will be described. The above-mentioned aliphatic polyester segment (B1) has a main dicarboxylic acid component composed of an aliphatic dicarboxylic acid component. Specifically, glutaric acid, succinic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, Dodecanedioic acid, 2-methylsuccinic acid, 2
-Methyladipic acid, 3-methyladipic acid, 3-methylpentanedioic acid, 2-methyloctanedioic acid, 3,8-dimethyldecandioic acid, 3,7-dimethyldecandioic acid, and the like. These acids can be used alone or in combination of two or more.

More preferably, it is a saturated aliphatic dicarboxylic acid unit having 6 to 14 carbon atoms. Use of a saturated aliphatic dicarboxylic acid having 14 to 14 carbon atoms is effective in suppressing a randomization reaction of a polyester block copolymer described later. Therefore, the greater the proportion of the saturated aliphatic dicarboxylic acid units having 6 to 14 carbon atoms, the more the effect of suppressing the randomization reaction of the polyester block copolymer is increased. Therefore, all the dicarboxylic acid units constituting the aliphatic polyester segment (B1) It is preferred that 70 mol% or more, especially 80 mol% or more, based on the above, is a saturated aliphatic dicarboxylic acid unit having 6 to 14 carbon atoms. As such a saturated aliphatic dicarboxylic acid unit having 6 to 14 carbon atoms, adipic acid, pimelic acid,
Examples include saturated aliphatic dicarboxylic acid units composed of suberic acid, azelaic acid, sebacic acid, monodecandioic acid, dodecandioic acid, tridecandioic acid, tetradecandioic acid, and the like. These acids can be used alone or in combination of two or more.

The diol unit constituting the aliphatic polyester segment (B1) is ethylene glycol,
1,3-propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, neopentylglycol, 1,5-pentaneddiol, 3-methyl-
1,5-pentanediole, 1,6-hexanediol-
1,7-heptanediol, 1,8-octanediol, 2-methyl-1,8-octanediol, 1,9
And diol units consisting of -nonanediol, 1,10-decanediol, cyclohexanedimethanol, cyclohexanediol and the like. These may be used alone or in combination of two or more.

More preferably, it is a unit comprising an aliphatic diol having 5 to 12 carbon atoms. Use of an aliphatic diol having 5 to 12 carbon atoms is effective in suppressing a randomization reaction of a polyester block copolymer described later. Therefore, the higher the proportion of the aliphatic diol unit having 5 to 12 carbon atoms, the more the effect of suppressing the randomization reaction of the polyester block copolymer, so that all diols constituting the aliphatic polyester segment (B1) 70 mol% or more, especially 80 mol% or more based on the unit has 5 to 5 carbon atoms.
It is preferably 12 aliphatic diol units. Examples of the aliphatic diol unit having 5 to 12 carbon atoms include 1,1
5-pentaneddiol, 1,6-hexanediol,
1,7-heptanediol, 1,8-octanediol
1,9-nonandiole, 1,10-decandio-
Linear aliphatic diol unit consisting of 1,11-monodecandiole, 1,12-dodecandiole, etc .; neopentyl glycol, 2,2-diethyl-1,3-propanediol- 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediole,
Examples thereof include branched aliphatic diol units composed of 2-methyl-1,8-octanediol and the like. Above all, a branched aliphatic diol unit is preferable, and the flexibility and elongation of the conjugate fiber are greatly improved by including such a unit as a constituent requirement.

The aliphatic polyester segment (B
1) is, if necessary, 30 mol% or less, more preferably 20 mol% or less of another dicarboxylic acid unit, for example, a saturated alicyclic dicarboxylic acid such as cyclohexanedicarboxylic acid;
Aromatic dicarboxylic acids such as phthalic acid, terephthalic acid and isophthalic acid; unsaturated aliphatic dicarboxylic acids such as maleic acid, phthalic acid and itaconic acid; dicarboxylic acid units comprising halogen-containing dicarboxylic acids such as tetrabromophthalic acid One or two or more other diol units, for example, cycloaliphatic diols such as cyclohexanediol and cyclohexanedimethanol; 1,4-bis (β-hydroxyethoxy) benzene, p- It may have a diol unit consisting of an aromatic diol such as xylene glycol. Further, a unit composed of a small amount of a polycarboxylic acid such as trimellitic acid, trimesic acid, pyromellitic acid, and tricarballylic acid; trimethylolethane, trimethylolpropane, glycerin, 1,2-hexanetrio-
And a unit composed of a polyvalent alcohol such as pentaerythritol.

As described above, the aliphatic polyester segment (B1) contains 70 units of dicarboxylic acid units in order to suppress the randomization reaction of the polyester block copolymer.
It is preferred that at least mol% is a saturated aliphatic dicarboxylic acid unit having 6 to 14 carbon atoms, and at least 70 mol% of the diol units are aliphatic diol units having 5 to 12 carbon atoms.

The aliphatic polyester segment (B2) will be described. Aliphatic polyester segment (B
The hydroxycarboxylic acid unit constituting 2) is ε-
Hydroxycaproic acid, 6-hydroxyenanthic acid, 7
And units derived from a hydroxycarboxylic acid such as -hydroxycaprylic acid. Among them, it is preferable to use a unit derived from a saturated aliphatic hydroxycarboxylic acid. These hydroxycarboxylic acid units are 1
Not only species but also two or more species can be used in combination. When the saturated aliphatic hydroxycarboxylic acid unit is used, at least 60 mol% of all the hydroxycarboxylic acid units constituting the aliphatic polyester segment (B2),
It is particularly preferred that 70 mol% or more is a saturated aliphatic hydroxycarboxylic acid unit having 6 to 10 carbon atoms.

The aliphatic polyester segment (B3) will be described. Aliphatic polyester segment (B
3) is mainly composed of poly (alkylene oxide) glycol units, such as polyethylene glycol and poly (propylene oxide) glycol unit.
And poly (tetramethylene oxide) glycol, and these can be used alone or in combination of two or more. Preferably, a homopolymer of poly (tetramethylene oxide) glycol, or a random copolymer or block copolymer in which two or more kinds of repeating units constituting the homopolymer are copolymerized in random or block form, or A homopolymer or a mixed polymer obtained by mixing two or more of the copolymers is used.

The poly (alkylene oxide) glycol has a number average molecular weight of 400 to 8,000, preferably 5 to 8,000.
00-5000, especially 600-3500 is desirable.
If the number average molecular weight is less than 400, the blockability of the polyester block copolymer may decrease, and the heat resistance of the conjugate fiber may decrease. On the other hand, when the number average molecular weight exceeds 8000, the polyester block copolymer undergoes phase separation, hardly becomes a block copolymer, and it is difficult to impart elastic recovery to the conjugate fiber.

The polyester block copolymer according to the present invention may have only the aliphatic polyester segment (B1) or only the aliphatic polyester segment (B2), or the aliphatic polyester segment (B1) and the aliphatic polyester segment (B1). Both of the aliphatic polyester segments (B2) may be used in combination. It is preferable to use the aliphatic polyester segment (B1) from the viewpoint of thermal decomposition. In addition, the aliphatic polyether segment (B
3), the aliphatic polyester segment (B1) and the aliphatic polyester segment (B
2) and the aliphatic polyether segment (B3) may be used in combination. Aliphatic polyester ether (B3)
Is slightly inferior to the aliphatic polyester segment in terms of light resistance, oxidation deterioration resistance, flexibility of the drawn yarn, and the like. Therefore, it is preferable to use an aliphatic polyester segment depending on applications requiring requirements such as light resistance.

The intrinsic viscosity of the polyester block copolymer is preferably at least 0.8 dl / g when measured at 30 ° C. in a phenol / tetrachloroethane mixed solvent (equal weight ratio). It is preferably at least 0.9 dl / g, particularly preferably at least 1.1 dl / g.

Only the aliphatic polyester segment (B
When 1) and the aliphatic polyester segment (B2) are used, when the polyester block copolymer is melted, a randomization reaction proceeds between the aromatic polyester segment (A) and the aliphatic polyester segment, and the block is formed. It will spoil the nature. As a result, it becomes difficult to impart flexibility and elastic recovery to the conjugate fiber. In such a case, the concentration of terminal hydroxyl groups of the polyester block copolymer is preferably 10 μeq / g or less.

The polyester block copolymer comprising the aliphatic polyester segment (B1) and / or the aliphatic polyester segment (B2) and the aromatic polyester segment (A) is obtained by subjecting both to a transesterification reaction. However, it is preferable that at least one of the aromatic polyester and the aliphatic polyester is produced using potassium titanium oxalate as a catalyst in terms of durability such as hydrolysis resistance, color tone, and the like. This effect is particularly remarkable when polybutylene terephthalate produced using potassium potassium oxalate as a catalyst is used as the aromatic polyester. The term "potassium titanium oxalate" refers to a salt in which the carboxyl group of oxalic acid is in the form of a salt with titanium and potassium. Generally, about 0.5 mole of titanium atom and about 1 mole of potassium atom per mole of oxalic acid. Have a molar bond of the chemical formula K ₂ Ti (C ₂ O ₄ ) .nH ₂
Indicated by O. And such titanium potassium oxalate can be produced, for example, by sufficiently hydrolyzing oxalic acid and reacting with potassium titanate.However, the production method is not limited to this, and is represented by the above-mentioned chemical formula. Any titanium potassium oxalate can be used.

On the other hand, the aliphatic polyester segment (B
The polyester block copolymer obtained by using 3) is
Using an aromatic dicarboxylic acid, a low molecular weight diol and a polyalkylene glycol, polymerization can be carried out in the same manner as in a general polyester polycondensation reaction. When the above-mentioned potassium titanium oxalate is used as a polymerization catalyst, durability such as hydrolysis resistance and color tone are improved. Particularly, a polyester block copolymer comprising terephthalic acid, 1,4-butanediol and polyalkylene glycol is preferred.

The aromatic polyester segment (A) constituting the polyester block copolymer according to the present invention,
The composition ratio of the aliphatic polyester segment and / or the aliphatic polyether segment (B) is (A) /
(B) = 95 / 5-30 / 70, especially 90 / 10-4
0/60, and 80/20 to 40/60 (weight ratio)
It is preferred that If the constituent ratio of the aromatic polyester segment is too large, the flexibility and elastic recovery of the conjugate fiber may be reduced. On the other hand, if the constituent ratio is too small, the fibers adhere to each other and it is difficult to obtain a satisfactory fiber.

In the conjugate fiber of the present invention, the above-mentioned ethylene-vinyl alcohol-based copolymer (hereinafter abbreviated as EVa copolymer) and polyester block copolymer (hereinafter abbreviated as block copolymer) are used. The composite ratio of EV
a copolymer / block copolymer = 10/90 to 90/1
0, especially 25/75 to 75/25, and even 30/7
It is preferably from 0 to 70/30 (weight ratio). Ev
If the composite ratio of the copolymer a is too small, the hydrophilicity of the composite fiber will be insufficient, while if too large, the spinning processability will be poor and the elastic recovery of the composite fiber will be insufficient.

The composite form of the EVa copolymer and the block copolymer is not particularly limited, and may be any composite form in which the effects of the present invention are exhibited. Therefore, it is preferable that 60% or more, especially 70% or more of the fiber cross-sectional circumference is composed of the EVa copolymer. Specifically, E
A core-sheath composite fiber in which the Va copolymer has a sheath portion and the block copolymer has a core portion, a composite fiber in which the EVa copolymer and the block copolymer are bonded side by side,
Examples thereof include a multilayer-bonded conjugate fiber in which an EVa copolymer and a block copolymer are alternately multilayer-bonded, and a heterogeneous mixed conjugate fiber in which the composite form is random between single fibers.

In the case of the core-sheath type composite fiber, it can be used as it is as a textile product for clothing or living use, and is used as a false twisted structure yarn for woven or knitted fabric, or as a raw yarn structure yarn by air entanglement. It is also possible. In the case of multi-layer laminated composite fiber and random composite fiber, it can be used as a fiber product as it is, but the fact that splitting into fibrils by physical / chemical method to form a fiber product gives a soft texture. Is preferred.

The cross-sectional shape of the conjugate fiber of the present invention is not limited to a particular one, and may be a multi-leaf cross-section such as a round cross-section, an elliptic cross-section, a three- to eight-leaf cross-section, a polygonal cross-section such as a three-to-octagonal cross section,
Either solid fiber or hollow fiber may be used. A part can be divided, so-called fibrillated.

A known composite spinning method can be applied to a method for producing composite fibers having the above-described composite ratio, composite form, and cross-sectional shape. For example, a method in which two kinds of polymers are separately melted, weighed, guided to a spinneret, and spun into a desired composite form. The spun yarn may be once wound and stretched, or may be stretched without winding the spun yarn. The spun and drawn yarn is heat-treated with heated air, hot water, steam or the like as it is or in a relaxed state.

The conjugate fiber of the present invention is used not only as a long fiber (filament) but also as a short fiber (staple), and not only as a woven or knitted fabric, but also as a dry nonwoven fabric or a wet nonwoven fabric using the staple. Useful. Of course, the composite fiber of the present invention may be used 100% or may be mixed with other fibers. In that case, the mixing ratio of the composite fiber of the present invention is desirably 20% by weight or more. .

[0039]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples.
The physical property values in the examples are values measured and calculated by the following methods. (1) Intrinsic Viscosity of Polyester Block Copolymer The copolymer was dissolved in an equal weight mixed solvent of phenol / tetrachloroethane and measured at 30 ° C. (2) Hydroxyl group concentration The hydroxyl group concentration of the copolymer was determined by measurement of proton NMR [JEOLX-500NMR, manufactured by JEOL Ltd.]. (3) Carboxyl group concentration The pellet of the copolymer was dried, dissolved in benzyl alcohol at a temperature of 215 ° C. for 3 minutes, chloroform was added to the solution after the dissolution, and methanol of potassium hydroxide was added. The neutralization point was determined by titration using phenol red as an indicator with the phenol solution, and the carboxyl group concentration was calculated.

(4) Stretchability of yarn The drawn yarn is cut to a length of 10 cm, and a take-up speed of 200 mm
/ 50% elongation at / min, and after holding for 3 seconds after elongation, the stress is unwound, and the yarn length L2 (cm) at the moment when the stress is unwound
Was measured, and the elastic recovery rate was calculated by the following equation. Elastic recovery rate (%) = [{5- (L2-10)} / 5] ×
100 (5) Hydrolysis Resistance The drawn yarn was left in a natural length state at 70 ° C. and 95% relative humidity for 35 days. The tensile breaking strength of the yarn before and after standing was measured, and the hydrolyzability was evaluated based on the retention ratio of the strength after standing to the strength before standing. (6) Hand and softness of the fabric The sensory evaluation of the tactile sensation was conducted by a panel of 10 people, and the results are shown as average scores. The evaluation criteria are shown below. 3 points: It had a moist feeling, the feel was good, the texture was similar to cotton fiber, and it was also rich in elasticity and flexibility. 2 points: The touch was slightly inferior to the cotton fiber, and the elasticity and flexibility were slightly inferior. 1 point: It was uncomfortable and rough.

Reference Example 1 Sebacic acid having 10 carbon atoms (Sb
A) 20.2 kg and 3-methyl- having 6 carbon atoms
A reactor was charged with 14.2 kg of 1,5 pentaneddiol (MPD), and an esterification reaction was carried out under atmospheric pressure at a temperature of 200 ° C. while distilling off water generated outside the system. When the acid value of the reaction product became 10 or less, 11 g of titanium potassium oxalate catalyst was added, and at a temperature of 250 ° C., 200 mmHg
The reaction was continued while gradually reducing the pressure from to 100 mmHg. When the acid value of the reaction product reached 1.0, the degree of vacuum was gradually increased with a vacuum pump to complete the reaction (abbreviated as polyester B). 6000 g of polybutylene terephthalate having an intrinsic viscosity of 0.80 and the above polyester B4000
250 g with 30 g of sebacic acid (SbA)
At a reduced pressure of 0.3 mmHg for 150 minutes. As a result, as shown in Table 1, the intrinsic viscosity was 1.4.
A polyester block copolymer having dl / g, a hydroxyl group concentration of 3 μeq / g, and a carboxyl group concentration of 5 μeq / g was obtained.

Reference Examples 2 to 4 Polyester block copolymers were obtained in the same manner as in Reference Example 1 except that the acid component, diol component and catalyst shown in Table 1 were used. Table 1 shows the intrinsic viscosity, hydroxyl group concentration, and carboxyl group concentration of the obtained copolymer. However, in Reference Example 2, since polyethylene terephthalate was used as the polyester B, the temperature at which the copolymer was polymerized was set at 265 ° C., and the reaction time was appropriately changed to obtain a block copolymer having the physical properties shown in Table 1. A coalescence was obtained.

Example 1 Using methanol as a polymerization solvent, radical polymerization of ethylene and vinyl acetate was carried out at 60 ° C. to give an ethylene content of 44.
After preparing a mol% random copolymer and then performing a saponification treatment with caustic soda to obtain a saponified ethylene-vinyl acetate copolymer having a degree of saponification of 99% or more, the wet polymer was removed. The washing is repeated with a large excess of pure water containing a small amount of acetic acid, and the washing is repeated with a large excess of pure water to reduce the alkali metal ions and alkaline earth metal ions in the polymer to 10 ppm or less, respectively. Water was separated, and vacuum drying was sufficiently performed at 100 ° C. or less. The intrinsic viscosity of the obtained polymer was 1.05 dl / g. Using the obtained EVa copolymer and the block copolymer (abbreviated as TPEE-1) obtained in Reference Example 1, each was melt-extruded individually, and then weighed with a separate gear pump to obtain a composite ratio. EVa copolymer: block copolymer = 50: 50 (weight ratio), the former being a sheath,
An eccentric core-sheath type cross-sectional shape having the latter as a core was formed, melt-spun at a spinning temperature of 250 ° C., and wound at a speed of 1000 m / min. Then, drawing was performed at a magnification of 3.0 times with a roller heater at 65 ° C, and heat setting was performed with a plate heater at 130 ° C to obtain a drawn yarn of 75 denier / 24 filaments. The spinnability and stretchability were good.

Using the obtained drawn yarn as a warp and a weft, a plain fabric having a warp density of 85 yarns / inch and a weft yarn density of 81 yarns / inch was produced. Then, it was dried and preset by a conventional method. The obtained plain fabric was rich in elasticity and had flexibility. Furthermore, the hydrophilicity was also very good, and the touch was similar to cotton fiber. Table 2 shows the results. When the block copolymer constituting the drawn yarn was measured by NMR, no randomization reaction occurred.

Example 2 Spinning and drawing were carried out in the same manner as in Example 1 except that TPEE-2 shown in Table 1 was used as the block copolymer to obtain a drawn yarn of 75 denier / 24 filaments. .
A plain woven fabric was produced using the obtained drawn yarn. Spinnability,
There were no problems in stretchability and weaving. The plain fabric was excellent in elasticity and flexibility, and had a soft touch and a good feeling. Table 2 shows the results. When the block copolymer constituting the drawn yarn was measured by NMR, no randomization reaction occurred.

Example 3 Spinning and drawing were carried out in the same manner as in Example 1 except that TPEE-3 shown in Table 1 was used as the block copolymer to obtain a drawn yarn of 75 denier / 24 filaments. .
A plain woven fabric was produced using the obtained drawn yarn. Spinnability,
Although there was no problem in the stretchability, the long run property of the spinning was slightly inferior to those in Examples 1 and 2. The plain fabric was excellent in elasticity and flexibility, and had a soft touch and a good feeling. Table 2 shows the results. When the block copolymer constituting the drawn yarn was measured by NMR, no randomization reaction occurred.

Example 4 Spinning and drawing were carried out in the same manner as in Example 1 except that TPEE-4 shown in Table 1 was used as the block copolymer to obtain a drawn yarn of 75 denier / 24 filaments. .
A plain woven fabric was produced using the obtained drawn yarn. Spinnability,
Although there was no problem in the stretchability, the long run property of the spinning was slightly inferior to those in Examples 1 and 2. Although the plain woven fabric was excellent in elasticity and flexibility, it was slightly inferior in softness to the plain woven fabrics obtained in Examples 1 and 2. The touch was moist. Table 2 shows the results.

Example 5 A plain fabric was obtained by spinning and stretching in the same manner as in Example 1 except that the composite form was a side-by-side type cross section. There were no problems in spinnability, stretchability, and weaving. The obtained plain woven fabric was superior in stretchability to the plain woven fabric obtained in Examples 1 to 4, but was slightly inferior in hydrolysis resistance.

Example 6 Spinning and stretching were carried out in the same manner as in Example 1 except that the composite form was an 11-layer lamination type vertical split type sectional shape. A false twist having a false twist number of 3390 T / M is applied to the obtained drawn yarn by 1
It was applied at 70 ° C. to perform a division process. A plain fabric was produced using the split drawn yarns under the same conditions as in Example 1, and was subjected to relaxation, washing with water, drying and presetting. The obtained woven fabric was rich in elasticity and flexibility, and was very comfortable. Table 2 shows the results.

Comparative Example 1 In place of the EVa copolymer, nylon 6 [manufactured by Ube Industries, Ltd.
Spinning, stretching and weaving were performed in the same manner as in Example 1 except that 1013BK-1] was used. There were no problems in spinnability, stretchability, and weaving. Although the obtained plain fabric had sufficient elasticity, it was unsatisfactory in terms of hydrophilicity, had a slimy feeling, and lacked a dry touch feeling. Table 2 shows the results.

Comparative Example 2 Spinning, stretching and weaving were performed in the same manner as in Example 1, except that polyethylene terephthalate having an intrinsic viscosity of 0.65 was used instead of the block copolymer. There were no problems in spinnability, stretchability, and weaving. However, the level of elasticity of the obtained plain fabric was low.

[0052]

[Table 1]

[0053]

[Table 2]

[0054]

The conjugate fiber of the present invention has hygroscopicity and excellent flexibility and elastic recovery.
It is suitable for clothing use and inner use.

Claims (3)

[Claims] 1. A composite fiber comprising an ethylene-vinyl alcohol copolymer and a polyester block copolymer, wherein the polyester block copolymer comprises (i) an aromatic polyester segment (A) and an aliphatic polyester segment. And / or an aliphatic polyester segment (B), wherein (a) the aromatic polyester segment (A) is mainly composed of a dicarboxylic acid unit and a diol unit, and 70 mol% or more of the dicarboxylic acid unit is An aromatic dicarboxylic acid unit wherein 70 mol% or more of the diol unit is an aliphatic α, ω-diol unit having 2 to 4 carbon atoms, and 1,4
(B) an aliphatic polyester segment and / or an aliphatic polyether segment (B) is a dicarboxylic acid unit and a diol unit; Aliphatic polyester segment (B1) composed mainly of hydroxycarboxylic acid units (B2)
And an aliphatic polyether segment (B3) mainly composed of poly (alkylene oxide) glycol units
And (ii) the aromatic polyester segment (A) / aliphatic polyester segment and / or aliphatic polyether segment (B) has a weight ratio of 95/5 to 30/70. Characteristic composite fiber. 2. The polyester block copolymer comprises an aromatic polyester segment (A) and an aliphatic polyester segment (B), and has a carboxyl group concentration of 20 μeq / g or less. The conjugate fiber according to claim 1. 3. The polyester block copolymer according to claim 1, comprising an aromatic polyester segment (A) and an aliphatic polyester segment (B), and having a terminal hydroxyl group concentration of 10 μeq / g or less. The conjugate fiber according to the above.