JPH1046433A - Hygroscopic polyester fiber and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject fiber having a three layer structure comprising a core layer produced from a specific resin, a sheath layer produced form a specific resin and an intermediate layer interposed between the core layer and the sheath layer, not causing the breakage of the sheath layer due to a weight- reducing processing using an alkali, excellent in spinnability and light resistance and suitable for inner clothes, etc. SOLUTION: This hygroscopic polyester fiber has a three layer structure comprising (A) a core layer comprising a hydroscopic thermoplastic resin 3 such as a polyalkylene terephthalate containing 10-50wt.% of a polyalkylene glycol having an average mol.wt. of 2000-20000, (B) a sheath layer comprising an easily alkali-soluble resin 1 such as a copolymerized polyalkylene terephthalate copolymerized with >=2.5mol% of 5-sodium sulfoisophthalic acid, and (C) an intermediate layer disposed between the core layer and the sheath layer, comprising a polyester resin 2 more insoluble in an alkali than the sheath layer and containing 0.05-5wt.% of particles which comprise cerium oxide, talc, etc., and whose surfaces are coated with amorphous silica. The hydroscopic polyester fiber is preferably subjected to a weight-reducing treatment using an alkali to elute the sheath layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an inner, inner garment,
The present invention relates to a polyester fiber excellent in hygroscopicity and particularly suitable for use in clothing materials such as sports clothing, and a method for producing the same.

[0002]

2. Description of the Related Art Polyesters represented by polyethylene terephthalate have excellent mechanical and chemical properties, are used in a wide range of fields, and have a very wide range of uses, especially as synthetic fibers. However, since the fiber made of such polyester is hydrophobic,
Compared with natural fibers, the hygroscopicity is remarkably inferior, and the use in fields where hygroscopicity is required is greatly restricted.

Conventionally, various attempts have been made to impart hydrophilicity or hygroscopicity to polyester fibers, but most of the attempts are made by devising the fiber shape or by post-processing. For example, in Japanese Patent Publication No. 61-60188, a hollow fiber is produced by using a polyester containing an alkyl sulfonate, and by reducing the alkali, the fine pores are uniformly dispersed. A fiber having a partly formed through hole from the surface to the hollow portion is disclosed. This fiber is
Although it has some water absorption due to capillary action,
Since the polymer itself is hydrophobic, its hygroscopicity is limited.

On the other hand, polyester fibers have been proposed in which a hydrophilic agent such as polyalkylene glycol or polyalkylene glycol and a metal sulfonic acid derivative is blended during polymerization or spinning. However, these hydrophilizing agents,
In particular, polyalkylene glycols have an ether bond, and therefore have a very poor light resistance, and cannot be used depending on the application.

[0005] In order to solve this problem, conjugate fibers using a polymer containing a hydrophilic agent as a core component have been proposed. By using a polymer containing a hydrophilizing agent as a core component, a certain effect is recognized in light resistance.
However, when alkali weight reduction processing is generally performed to improve the texture, the core portion expands due to polyalkylene glycol absorbing water and decomposing by alkali. Cracks and cracks occur, and the moisture-absorbing components in the core having high alkali solubility are eluted.

[0006] In order to prevent this sheath cracking, a hollow portion is provided inside the core-sheath structure (Japanese Patent Laid-Open No. 4-108113), or a three-layer structure in which a moisture-absorbing component is interposed between polyalkylene terephthalates ( Japanese Unexamined Patent Publication No. 7-278960) has been proposed, but also has a problem that under severe processing conditions, a sheath crack occurs under the severe processing conditions, resulting in a hollow fiber in which a part of the core is eluted.

[0007]

DISCLOSURE OF THE INVENTION The present invention relates to a polyester fiber which can be produced with good yarn-making properties, has no problem of sheath cracking due to alkali weight reduction processing, and has excellent hygroscopicity (and light resistance). It is intended to provide a manufacturing method.

[0008]

The present invention solves the above-mentioned problems, and the gist thereof is as follows. (1) a core layer made of a thermoplastic resin having a hygroscopic property, a sheath layer made of an alkali-soluble resin, and an intermediate layer made of a polyester resin that is less alkali-soluble than the sheath layer disposed between the core layer and the sheath layer. A polyester fiber having a three-layer structure of the above. (2) A method for producing a hygroscopic polyester fiber, comprising subjecting the above polyester fiber or a textile fiber obtained by knitting or weaving the polyester fiber to an alkali weight reduction treatment and eluting and removing a sheath layer.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

In the present invention, examples of the hygroscopic thermoplastic resin constituting the core layer include polyamides such as nylon 4 and nylon 2T, polyetheramide, polyetherester, polyetheresteramide, ethylene / vinyl acetate. Hygroscopic thermoplastic resins such as saponified copolymers, mixtures of these hygroscopic thermoplastic resins with hydrophobic thermoplastic resins such as polyesters, polyamides, polyolefins and sodium polyacrylate, poly-
N-vinylpyrrolidone, polyacrylic acid and its copolymer, polymethacrylic acid and its copolymer, and a mixture of a water-absorbing resin and a hydrophobic thermoplastic resin such as a crosslinked polyethylene oxide-based polymer.

Of these, polyalkylene glycol having an average molecular weight of 2,000 to 20,000 is incorporated in an amount of 10 to 50% by weight, preferably
A polyalkylene terephthalate containing 15 to 35% by weight exhibits extremely high hygroscopicity, and has good spinning and stretching properties, and is advantageous in terms of cost, and is therefore preferably used. (In addition, "polyalkylene glycol" includes
It also includes those whose terminals are etherified and those which are esterified. If the molecular weight of the polyalkylene glycol is too small, sufficient hygroscopicity is not exhibited, and if it is too large, the operability during spinning is remarkably reduced, which is not preferable. Also,
If the content of the polyalkylene glycol is small, sufficient hygroscopicity will not be exhibited, and if it is too large, the operability will be significantly reduced, which is not preferable. In addition, when a compound having a sulfonic acid group such as 5-sodium sulfoisophthalic acid is copolymerized, the hygroscopicity can be further improved. In this case, the amount of the copolymer component is desirably 10 mol% or less of the total acid components. If the amount of the copolymer component is too large, the spinnability deteriorates.

In the present invention, the polyester forming the intermediate layer is preferably polyalkylene terephthalate, specifically, polyethylene terephthalate (PET) or polybutylene terephthalate. The polyalkylene terephthalate may contain a small amount of a copolymer component as long as the alkali solubility is not so large. Examples of the copolymer component include 5-sodium sulfoisophthalic acid, isophthalic acid, phthalic anhydride, and naphthalenedicarboxylic acid. Aromatic dicarboxylic acid components such as acids, aliphatic dicarboxylic acid components such as adipic acid and sebacic acid, diethylene glycol, propylene glycol, 1,4-cyclohexanedimethanol, pentaerythritol, and alkylene oxide adducts of bisphenol A and bisphenol S. Examples include hydroxycarboxylic acid components such as diol components, 4-hydroxybenzoic acid, and ε-caprolactone.

The sheath layer is eluted and removed by alkali reduction treatment, and the alkali-soluble resin constituting the sheath layer preferably has a rate of dissolving alkali more than twice as high as that of the polyester in the intermediate layer. . Specific examples of such an alkali-soluble resin include metal sulfonates such as 5-sodium sulfoisophthalic acid.
Copolymerized PET obtained by copolymerizing 5 mol% or more, and copolymerized PET obtained by copolymerizing a metal sulfonate and a polyalkylene glycol are exemplified.

In the present invention, the ratio between the core layer and the intermediate layer is preferably in the range of 15/85 to 85/15 by volume. If the ratio of the core layer is smaller than this, the hygroscopicity is inferior. On the other hand, if the ratio of the sheath is smaller than this, cracks occur in the intermediate layer during alkali weight reduction treatment, which is not preferable.

On the other hand, the ratio of the sheath layer is preferably in the range of 25 to 10% by volume of the whole fiber. Since the sheath layer is to be eluted and removed by the alkali weight reduction treatment, if this ratio is too large, not only the cost is increased but also the intermediate layer is cracked and the core layer is eluted, which is not preferable. On the other hand, the alkali weight loss treatment is to improve the texture of the fabric, and a weight loss of about 20% by weight is generally effective.
If the ratio of the sheath layer is too small, the alkali weight reduction treatment cannot be performed without affecting the intermediate layer and the core layer.

In the present invention, if the intermediate layer and / or the core layer contains particles (light-fasting agent particles) comprising cerium oxide and talc or cerium oxide and silica and the surface of which is coated with amorphous silica, the light-fastness is improved. It is preferable because it can be improved. As such light stabilizer particles, those having an average particle diameter of 0.1 to 3.0 μm are preferable, and those commercially available from Nippon Inorganic Chemical Industry Co., Ltd. under the trade name of “Serigard” can be used.

The amount of the light stabilizer particles to be added is suitably 0.05 to 5% by weight based on the resin of the core layer or the intermediate layer.
If the amount is less than 0.05% by weight, excellent light fastness cannot be obtained. If the amount exceeds 5% by weight, the particles are likely to aggregate, deteriorating the spinning operability and deteriorating the color tone of the fiber.

The composite form of the fiber may be any of concentric type and eccentric type and multi-core type as long as the intermediate layer does not crack or crack due to the alkali weight reduction treatment. Further, the cross-sectional shape of the fiber may be an irregular cross-section such as triangular, flat, or multi-leaf type in addition to the circular shape. Further, a hollow portion can be provided inside the core layer.

In the present invention, the three kinds of resins are melt-spun, drawn and heat-treated in a conventional manner to obtain a three-layered conjugate fiber.

The resulting three-layered conjugate fiber is subjected to alkali weight reduction treatment to elute and remove the sheath layer, resulting in a two-layered conjugate fiber having excellent hygroscopicity. The alkali weight reduction treatment can be performed in the state of a fiber (raw yarn or raw cotton), but usually, 3
After performing false twisting or twisting as necessary on the composite fiber having a layered structure, knitting and weaving is performed using the whole or a part of the composite fiber as a fabric, thereby improving the texture and improving moisture absorption. The resulting fabric is obtained.

The alkali weight reduction treatment may be carried out using a sodium hydroxide aqueous solution according to a conventional method for alkali weight reduction processing of polyester fibers.

The drawings are cross-sections of the three-layered conjugate fiber of the present invention ((a) in each figure) and the two-layered conjugate fiber ((b) in each figure) obtained by subjecting it to an alkali reduction treatment. FIG. 1 shows an example of a concentric type, FIG. 2 shows an example of an eccentric type, and FIG. 3 shows an example of a multi-core type. In the figure, 1 indicates an alkali-soluble resin (sheath layer), 2 indicates a polyester resin (intermediate layer), and 3 indicates a thermoplastic resin (core layer) having hygroscopicity.

[0023]

According to the present invention, since the rate of weight loss of the sheath layer is high, the alkali weight reduction treatment can be performed without affecting the intermediate layer and the core layer. And, while the texture of the fabric is improved by the alkali weight loss treatment, and the fiber surface becomes a relatively hydrophobic polyester, the fiber surface is always smooth even in a high-humidity environment, and there is little discomfort due to stickiness. A fabric with good wearing comfort is obtained. In addition, if the core layer and / or the intermediate layer contains light-resistant agent particles, a moisture-absorbing polyester fiber having excellent light resistance can be obtained.

[0024]

Next, the present invention will be described specifically with reference to examples. The methods for measuring and evaluating characteristic values and the like in the examples are as follows. (a) Intrinsic viscosity ([η]) Measured at a temperature of 20 ° C. using an equal weight mixture of phenol and ethane tetrachloride as a solvent. (b) Alkali solubility 5 g of a polymer is heated to 70 ° C.
The weight loss rate obtained from the change in weight when treated for 2 hours was used as an index. (c) Strong elongation Measured at a sample length of 50 cm and a tensile speed of 50 cm / min using Tensilon UTM-4-100 manufactured by Orientic. (d) Hygroscopicity The woven fabric is conditioned at 25 ° C. and 60% RH, and the weight W ₀ is measured.
Next, the woven fabric is dried at 80 ° C. for 6 hours under a reduced pressure of 2 Torr, left in a thermo-hygrostat set at 34 ° C. × 90% RH for 6 hours, and the weight W ₁ is measured. Then, the moisture absorption rate is calculated by the following equation. Moisture absorption (%) = [(W ₁ −W ₀ ) / W ₀ ] × 100 (e) Light fastness The light fastness of dyeing was measured according to JIS L-0841-74. (f) Evaluation of cracks Decompose the woven fabric, take out the composite yarn, sample the fiber cross section in a flake shape, observe the presence or absence of cracks for each single yarn with a microscope, according to the ratio of the number of cracked single yarns, Evaluation was made according to the following criteria. ：: 0%, Δ: less than 15%, ×: 15% or more (g) Texture The fabric was evaluated in the following three stages by a sensory test after the finish setting. ：: extremely good, △: good, ×: bad

"Serigard T-3018" used in Examples and Comparative Examples is a trade name of Nippon Inorganic Chemical Industry Co., Ltd., in which particles of cerium oxide and talc are coated with amorphous silica. The weight ratio of cerium oxide: talc: amorphous silica is 30:52:18.

Reference Example 1 A slurry of terephthalic acid and ethylene glycol at a molar ratio of 1 / 1.6 was continuously supplied to an esterification reactor in which bis (β-hydroxyethyl) terephthalate and its oligomer were present, and the mixture was heated at normal pressure and temperature. The esterification reaction was carried out at 250 ° C. with a residence time of 6 hours, and an esterification product having an average degree of polymerization of 7.5 was continuously obtained. To 36.3 kg of this esterification product, 15.0 kg of polyethylene glycol having an average molecular weight of 8500 was added, and the mixture was stirred and mixed for 30 minutes.
1.318 kg of a 10% by weight ethylene glycol solution, 4 × 10 ⁻⁴ mol of antimony trioxide and sodium acetate in a 5% by weight ethylene glycol solution of 0.5 mol per mol of all acid components
kg, and then 0.5 mol% of 5-
Ethylene glycol ester of sodium sulfoisophthalic acid (SIP) was added, and the pressure was gradually reduced.
The polycondensation was performed at 0.5 torr and a temperature of 270 ° C. for 3 hours. The obtained polyester (referred to as polymer A) had a good color tone, and [η] was 0.83. Table 1 shows the characteristic values of the polymer A and the like.

Reference Examples 2 to 11 In the same manner as in Reference Example 1, except that the molecular weight and the addition amount of polyethylene glycol, the addition amount of SIP and the addition amount of "Serigard T-3018" were changed to the values shown in Table 1. Polyesters (referred to as polymers BK) were obtained. Table 1 shows the characteristic values and the like of the polymers B to K.

[0028]

[Table 1]

Example 1 The polymer A obtained in Reference Example 1 was used for the core layer, the polymer B obtained in Reference Example 2 was used for the intermediate layer, and the polymer C obtained in Reference Example 3 was used for the sheath layer. The composite ratio (volume ratio) of the intermediate layer / sheath layer was 65/15/20, and the undrawn yarn was wound at a speed of 1400 m / min by discharging from a die device for a concentric three-layer composite fiber. This undrawn yarn is supplied to a normal drawing machine, preheated at 80 ° C, drawn 3.5 times, heat-treated while being in contact with a heat plate at a temperature of 150 ° C, and wound to obtain a 75d / 36f composite yarn. Was. Further, this composite yarn is used as a warp and a weft, and a non-twisted plain fabric is woven at a warp density of 110 yarns / 2.54 cm and a weft yarn density of 78 yarns / 2.54 cm, scoured according to a conventional method, and then refined.
With a 0.5% by weight aqueous solution of sodium hydroxide, a temperature of 95%
After alkali reduction treatment was performed at 20 ° C. for 20 minutes to completely remove the sheath layer, dyeing and finishing were performed according to a conventional method. The texture of the obtained fabric was good, the moisture absorption was 5.9%, and the dyeing and light fastness class 5 was excellent.
Further, the woven fabric was disassembled to take out the composite yarn, and the cross sections of all 36 single yarns constituting the composite yarn were observed, but none of the single yarns had cracks or cracks on the surface layer. Table 2 shows the strength and elongation of the composite yarn and the evaluation results of the woven fabric.

Examples 2 to 13 and Comparative Example 1 The same procedure as in Example 1 was carried out except that the composite yarn was spun while changing the polymer and the composite ratio as shown in Table 2.
In addition, "Aqua Coke" used for the core layer of Examples 12 and 13
Is a trade name of Sumitomo Seika Co., Ltd., a water-absorbing resin composed of a crosslinked product of polyethylene oxide. In Example 13, an equal weight mixture of “Aqua Coke” and nylon 6 (N6) was used. Table 2 shows the strength and elongation of the composite yarn and the evaluation results of the woven fabric.

Comparative Example 2 A composite yarn was spun in the same manner as in Example 1 except that the polymer and the composite ratio were changed as described in Table 2, but the yarn breakage occurred frequently during spinning, and the operability was extremely poor. .

[0032]

[Table 2]

Comparative Example 3 The polymer A obtained in Reference Example 1 was used for the core layer, and the reference example 2 was used for the sheath layer.
Using the polymer B obtained in the above, the core layer / sheath layer was discharged from the concentric core / sheath composite fiber die at a compounding ratio (volume ratio) of 50/50 at a composite ratio (volume ratio) of 50/50. A core-sheath type (two-layer structure) composite yarn was obtained. The obtained composite yarn is woven as a warp and a weft in the same manner as in Example 1, scoured according to a conventional method, and then reduced in alkali with a 0.5% by weight aqueous solution of sodium hydroxide at a temperature of 95 ° C for 20 minutes. Processing was performed, and dyeing and finishing setting were performed in the same manner as in Example 1. The obtained woven fabric was decomposed to take out the composite yarn, and the cross section of all 36 single yarns constituting the composite yarn was observed, but the surface layer of all the single yarns was broken, and the moisture-absorbing component of the core layer was eluted, Some were hollow. As a result, stained spots were observed and were not usable. Table 3 shows the strength and elongation of the composite yarn and the evaluation results of the woven fabric.

Comparative Examples 4 to 8 Comparative examples 4 to 8 were carried out in the same manner as in Comparative Example 3 except that the composite yarn having a two-layer structure was spun by changing the polymer and the composite ratio as shown in Table 3. Disassemble the obtained woven fabric and take out the composite yarn,
The cross section of all 36 single yarns that compose the composite yarn was observed,
The surface layers of all the single yarns were cracked, and the moisture-absorbing components of the core layer were eluted, and some were hollow. As a result, stained spots were observed and could not be put to practical use. Table 3 shows the strength and elongation of the composite yarn and the evaluation results of the woven fabric.

Comparative Example 9 The composite yarn obtained in Comparative Example 6 was scoured in the same manner as in Comparative Example 6, and the weight was reduced until the alkali weight loss rate became 20%. Was done. The obtained woven fabric was decomposed to take out the composite yarn, and the cross section of all 36 single yarns constituting the composite yarn was observed, but the surface layer of all the single yarns was broken, and the moisture-absorbing component of the core layer was eluted, Some were hollow. As a result, stained spots were observed and could not be put to practical use. Table 3 shows the strength and elongation of the obtained composite yarn and the evaluation results of the woven fabric.

[0036]

[Table 3]

[0037]

According to the present invention, a polyester fiber which can be produced with good yarn-making properties, has no problem of sheath cracking due to alkali weight reduction processing, and has excellent moisture absorption (and light resistance) and a method for producing the same. Is provided.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a cross section of a conjugate fiber having a concentric three-layer structure (a) of the present invention and a conjugate fiber having a two-layer structure obtained by subjecting it to an alkali weight reduction treatment (b).

FIG. 2 is a view schematically showing a cross section of an eccentric type three-layer composite fiber (a) of the present invention and a two-layer composite fiber (b) obtained by subjecting the composite fiber to alkali reduction treatment.

FIG. 3 is a diagram schematically showing a cross section of a multifilamentary three-layered conjugate fiber (a) of the present invention and a two-layered conjugate fiber (b) obtained by subjecting it to an alkali reduction treatment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Alkali easily soluble resin 2 Polyester resin 3 Moisture-absorbing thermoplastic resin

Claims (4)

[Claims] 1. A core layer made of a thermoplastic resin having hygroscopicity, a sheath layer made of an alkali-soluble resin, and a polyester resin which is less soluble in alkali than the sheath layer disposed between the core layer and the sheath layer. A hygroscopic polyester fiber having a three-layer structure of an intermediate layer. 2. The thermoplastic resin of the core layer has an average molecular weight of 2000.
The moisture-absorbing polyester fiber according to claim 1, which is a polyalkylene terephthalate containing 10 to 50% by weight of a polyalkylene glycol of about 20,000. 3. The resin of the core layer and / or the intermediate layer is composed of cerium oxide and talc or cerium oxide and silica, and has particles whose surface is coated with amorphous silica.
The moisture-absorbing polyester fiber according to claim 1, which contains about 5% by weight. 4. A method for producing a hygroscopic polyester fiber, comprising subjecting the polyester fiber according to claim 1, 2 or 3 or a fabric-like fiber obtained by knitting the same to alkali weight reduction and eluting and removing a sheath layer. .