JP2003221732A - Polyester fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester fiber having silk-like soft touch and squeaky touch and decreasing environmental load. <P>SOLUTION: This polyester fiber is characteristically obtained by mixing 85.0-99.5 wt.% polyester A composed mainly of lactic acid with 0.5-15.0 wt.% polymer B having ≤1/30 alkali weight-loss rate based on the polymer A. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester fiber, more specifically, a polyester fiber made of a mixed polyester of polylactic acid and other polyesters, and more specifically, to obtain a silky touch and stain when formed into a cloth. Thus, the present invention relates to a polyester fiber which not only provides a feel very similar to a cloth made of silk but also reduces environmental load by mainly using non-petroleum raw materials.

[0002]

2. Description of the Related Art Polyester fibers are widely used for clothing because of their excellent functionality. Particularly in the field of women's clothing, there is a strong demand for further improvement in texture due to the trend toward high-class products in recent years. For this reason, many techniques have heretofore been proposed in which a fine texture is formed on the polyester fiber to impart a dry texture or enhance the color developability. For example, in JP-A-54-120728, JP-A-55-107512, JP-A-55-51819 and JP-A-3-124852, various particles are blended to form fine particles on the fiber surface. It has been proposed to provide a dry-touch texture or to improve color development by forming unevenness, but all of them must impart a high-grade dry-touch texture and silky squeaky feeling. I couldn't.

On the other hand, as another method, for example, Japanese Patent Application Laid-Open No.
8-98474 and Japanese Unexamined Patent Publication (Kokai) No. 6-41836 propose a method of adding an additive which is incompatible with polyester. According to the method proposed in this publication, the fiber surface is fibrillated, so that a fabric having a silky soft touch with a fluffy feeling can be obtained, but it is outside the concept of environmental load reduction which has been attracting attention in recent years. In addition, since the fiber substrate itself does not have a squeaky feeling, a sufficient effect was not obtained.

Further, in JP-A-8-209529, a modified polyester obtained by mixing a thermoplastic aliphatic polyester and a thermoplastic polyester having a lower solubility in an alkaline aqueous solution than that has a streaky irregularity on the fiber surface. A method of forming and obtaining a squeaky feeling has been proposed. However, with this method, a silky squeaky feeling can be obtained, but a soft tactile sensation cannot be obtained.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyester fiber capable of obtaining a soft touch and a blotchy feeling that a cloth made of silk has, which cannot be achieved by the above conventional techniques. .

[0006]

The object of the present invention is to provide a polyester A whose main constitutional unit is lactic acid is 85.0-9.
9.5% by weight, 0.5 to 15.0% by weight of polymer B, which is 30 times slower in alkali reduction rate than polyester A
It can be achieved by a polyester fiber characterized by being mixed with.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. The polyester fiber of the present invention contains 85.0 to 99.5% by weight of polyester A whose main constituent unit is lactic acid.
And a polymer B characterized in that the rate of alkali reduction is 30 times or more slower than that of the polyester A, and 0.5 to 15.0% by weight of the polymer B is mixed.

Polyester A having lactic acid as a main constituent unit and polyester B obtained by mixing a polymer B characterized by an alkali weight loss rate of 30 times or more slower than the polyester A in a specific ratio It has become possible.

The polyester fiber in the present invention is a thermoplastic aliphatic polyester which is biodegradable and uses a non-petroleum raw material, from the viewpoint of reducing the environmental load. Specific examples of the thermoplastic aliphatic polyester include polybutylene succinate, polyethylene succinate, polyhexamethylene fumarate and polybutylene adipate.
It is important that the polylactic acid has a relatively high melting point, good fiber-forming properties, and has a squeaky feeling on the fiber substrate itself. The weight average molecular weight of the polylactic acid used as the polyester A is not particularly specified, but from the viewpoint of stable spinning and easiness of spinning technology, it is 100,000 to 20.
It is preferably about 10,000, and 20% by weight or less of the third component may be copolymerized without impairing the object of the present invention.

Further, in order to form fibrils on the fiber surface, as the polymer B to be mixed in a small amount, one having an alkali reduction rate which is 30 times or more slower than that of the polyester A is used, and more preferably 40 times or more. . By forming fibrils on the fiber surface, a silky soft touch can be obtained. Specific examples of the polymer B include polyamides such as nylon 6 and nylon 66. From the viewpoints of yarn-forming stability, fabric quality, and weaving / knitting properties when mixed-spun with polylactic acid, ethylene terephthalate, propylene terephthalate, butylene terephthalate. Among them, a polyester having at least one kind as a main constituent unit is preferable, and the melting point is relatively low,
More preferably, it is propylene terephthalate or butylene terephthalate, which has a slower alkali weight loss rate.

The main constituent unit means that it is formed mainly of the monomer shown in the present invention, and 20 mol% or less of the third component may be copolymerized. Preferred copolymerization components include dibasic acids such as adipic acid, sebacic acid, isophthalic acid, diphenyldicarboxylic acid and naphthalene dicarboxylic acid, oxyacids such as oxybenzoic acid, and glycols such as diethylene glycol and polyethylene glycol, 5-sodium. Sulfoisophthalic acid, 2,2-bis {4- (2-hydroxyethoxy)
Examples thereof include polyesters obtained by copolymerizing one or more of phenyl} propane and the like.

Further, in order to form fibrils in the polyester fiber of the present invention, the mixing ratio of the polymer B is 0.5% by weight or more. 0.5% by weight
If it is less than the above range, fibrils are formed, but it is difficult to achieve the effect of silky touch. A more preferable mixing ratio of the polymer B is 1.0% by weight or more. When the mixing ratio of the polymer B is higher than 15% by weight, the fibril generation frequency becomes excessively high, and the polyester A preferentially occurs.
Since the amount of alkali decreases the strength of the fabric and the resulting fabric becomes poor in practicality, the mixing ratio of the polymer B is 15% by weight or less, and more preferably 10% by weight or less.

The weight reduction processing with the alkaline aqueous solution was performed by the following method. 0.5% of the polyester fiber of the present invention
% Caustic soda aqueous solution, bath ratio 1: 125, temperature 98-10
Treat at 0 ° C. Further, the weight loss rate described in the present invention is that after the polyester A or the polymer B is made into a fiber, the above weight reduction processing is performed until the weight loss rate of either one becomes 50%, and from the weight loss rate per unit time, Calculated and compared.

The method of mixing the polyester A and the polymer B in the present invention is not particularly limited, and mixing at the chip stage, or a static kneading element incorporated in a pipe or a pack after melting both polymers is used. A mixing method may be mentioned, but in order to maintain the mixed state uniform, the latter method of measuring and mixing both polymers after melting is preferable.

The method for producing the polyester fiber of the present invention is not particularly limited, but the undrawn yarn obtained by winding at a low spinning speed of less than 2000 m / min has poor deformability, and thus is not spun. A method of once winding at a speed of 2000 m / min or more and then stretching, a method of continuously stretching without once winding, and a method of high-speed spinning at 4500 m / min or more are preferable.

[0016]

The present invention will be described in more detail with reference to the following examples. In addition, the respective characteristic values of the texture characteristics (softness and squeaky feeling), fabric evaluation, and spinnability in the examples were determined by the following methods,
All items are evaluated as follows: Excellent: ○○, Excellent: ○,
The evaluation was carried out in four stages of good: Δ and poor: ×. A. Texture characteristics (soft and squeaky feeling) For each characteristic, a plain woven sample was subjected to a weight reduction process of 15% by weight with a hot alkaline aqueous solution, and then a pairwise comparison with a reference sample was performed by five skilled engineers for sensory evaluation. It was carried out in. As the reference sample, a polyester filament yarn, which is usually used as a standard variety, and silk which was similarly woven and processed were used, and the former was rated as poor and the latter was rated as excellent. B. Fabric evaluation Overall weaving property of plain weave, fabric quality and quality such as fluff, stain spots, tear strength, etc. are evaluated comprehensively according to the above criteria, and fluff with a large number of occurrences and low tear strength are defective. And C. Spinnability was comprehensively judged from the product yield of the polyester fiber obtained by the method described in the present invention and the product quality such as fluff and tarmi. Excellent: Product yield 90% or more Excellent: Product yield 80% or more, less than 90% Good: Product yield 70% or more, less than 80% Poor: Product yield less than 70% Example 1 Average molecular weight of 130,000 Polylactic acid to polyester A
The main repeating unit is propylene terephthalate as the polymer B, each component is melted in a separate melting device, and the mixing ratio of the polyester A and the polymer B is adjusted to 95: 5 by weight in the measuring device. After weighing, mixing with a static kneader installed in the polymer pipe, spinning at a spinning temperature of 260 ° C., once winding at 3000 m / min, and subsequently stretching at a draw ratio of 1.5 times , 84 dtex, 24 filaments of polyester fiber were obtained. The weight reduction ratio of each polymer was polyester A: polymer B = 120: 1.

A plain weave of such polyester fibers is used, and the weight loss rate is 15% in an alkaline aqueous solution by the method described in the present invention.
After reduction processing was performed so that

The results are shown in Table 1. The yarn-forming property when obtaining the polyester fiber was as good as a product yield of 96%, a silky soft touch and a squeaky feeling were obtained, and the weavability and the fabric quality were also good. The soft feeling in the table means a silky soft touch feeling.

Examples 2-5 and Comparative Examples 1-2 Polylactic acid having an average molecular weight of 170,000 in Example 1 was used as polyester A, and the ratio of polymer B was changed as shown in Table 1 for each property. Table 1 shows the results of evaluation by the same method as in 1. The weight reduction rate ratio of each polymer was polyester A: polymer B = 100: 1.

In Examples 2 to 5, the texture properties, the fabric evaluation, and the spinnability were good. The higher the ratio of polymer B, the more fibrils tended to be formed on the fiber surface, tending to increase the softness and squeaky feeling, but in Example 5, the squeaky feeling was slightly reduced, and fluff during weaving The frequency of occurrence was high. In Comparative Example 1, fibrils were scarcely formed so that there was no soft feeling, and in Comparative Example 2, the weavability was remarkably deteriorated due to frequent occurrence of fluff.

[0021]

[Table 1]

Examples 6 to 9 Polyethylene terephthalate (hereinafter referred to as PET), polybutylene terephthalate (hereinafter referred to as PBT), nylon 6 (hereinafter referred to as N6) and nylon 66 (hereinafter referred to as N66) were used as the polymer B in Example 1. ) Are each melted in a separate melting device, and the mixing ratio of polyester A and polymer B in the weighing device is 95:
After being weighed to be 5, the mixture was mixed with the static kneader installed in the spinning pack, then taken up at 1500 m / min, and taken up at 4500 m / min without taking up once to obtain 84 dtex of 24 filaments. A polyester fiber was obtained. In addition, PET, P for polyester A
The weight reduction rates of BT were 1/30 and 1/240, respectively, and N6 and N66 were not alkali-reduced.

Table 2 shows the results of an evaluation in the same manner as that described in Example 1 using a plain weave of such polyester fibers.

Although all the fabrics had good texture characteristics, differences were found in the yarn-forming property, the weaving property, and the fabric quality. In Example 6, since the spinning temperature was set to 280 ° C. due to the high melting point of PET, the spinnability tended to deteriorate due to the thermal deterioration of the polyester A. Further, in Examples 8 to 9 in which nylon was used as the polymer B, there was a tendency that the frequency of occurrence of fluff during yarn making and weaving increased. The cause is not clear, but it is presumed that fibrillation is progressing before the alkali reduction treatment.

[0025]

[Table 2]

Comparative Example 3 The ratio of polymer B in Example 1 was set to 10%, polyester A was mixed so as to form islands of 10 islands, and polymer B was formed in the sea, and the same evaluation was carried out. Shown in. The yarn-forming property and the weaving property were good, but fibrils did not occur on the surface of the obtained polyester fiber, and neither soft feeling nor squeaky feeling was obtained.

[0027]

[Table 3]

Comparative Example 4 Table 4 shows the results of the same evaluation as in Example 1 except that the polymer B was polybutylene succinate and the spinning temperature was 220 ° C. The weight reduction ratio of each polymer was polyester A: polymer B = 1: 20. No squeaky feeling, yarn-forming property, weaving property, and fabric quality were found, but no fibrils were generated and a soft feeling was not obtained.

[0029]

[Table 4]

[0030]

INDUSTRIAL APPLICABILITY According to the present invention, 85.0 to 99.5% by weight of polyester A whose main constituent unit is lactic acid is 30% or more slower than that of polyester A in alkali reduction, and polymer B is By using a polyester fiber characterized by being mixed with 0.5 to 15.0% by weight, not only a silky soft touch and a squeaky feeling can be obtained, but also a fabric having a reduced environmental load can be obtained. it can.

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 4J002 CF052 CF062 CF072 CF181                       CL012 CL032 GK01                 4L035 BB33 HH01

Claims (2)

[Claims] 1. A polyester A whose main constituent unit is lactic acid is 85.0 to 99.5% by weight, and a polymer B whose alkali reduction rate is 30 times or more slower than that of the polyester A is 0.5.
Polyester fiber characterized by being mixed with ˜15.0% by weight. 2. The polyester fiber according to claim 1, wherein the polymer B is a polyester containing at least one of ethylene terephthalate, propylene terephthalate and butylene terephthalate as a main repeating unit.