JPH0473217A - Highly shrinkable polyester fiber - Google Patents

Abstract

PURPOSE:To provide the subject fiber containing polyethylene terephthalate as the core part and a polyester as the sheath part at a specific conjugation ratio, free from fusing and agglutination defect and giving a combined filament yarn having extremely high bulkiness by mixing with other fibers and treating with hot water. CONSTITUTION:The objective fiber is core-sheath polyester conjugate fiber containing (A) a polyethylene terephthalate copolymerized with cyclohexanedimethanol constituting 15-35 mol% of the glycol component as the core part on the cross-section of single filament and (B) a sheath part made of a polyester containing ethylene terphthalate accounting for >= 88 mol% of the constituent unit. The conjugation ratio of the core part to the sheath part is (10-2):1.

Description

[Detailed description of the invention] (Field of application of the invention) The present invention relates to highly shrinkable polyester fibers.

Specifically, the present invention relates to an ultra-high shrinkage polyester fiber that can be mixed with other yarns and treated with hot water to form a mixed yarn with extremely high bulkiness, and which is free from fusing and sticking.

(Prior Art) For the purpose of improving the feel, especially the bulkiness, of woven or knitted fabrics using polyester fibers, a method of using different shrinkage mixed fiber yarns is generally used. This is obtained by mixing fibers with high shrinkage and fibers with low shrinkage. A method for obtaining polyester fibers with low shrinkage is to perform crystallization using high-temperature heat centrifugation and/or a relaxation heat treatment after drawing.To obtain fibers with large shrinkage, polyester fibers are not heat set during drawing and/or polyester fibers are not heat-set during drawing. There is a method of making fibers of a polyester polymer by copolymerizing terephthalate with another type of acid component or glycol component. By combining these two methods, a bulky mixed fiber yarn can be obtained.
No. 126934 is mentioned.

If you want to obtain a blended yarn with extremely high bulk, you can use ultra-high shrinkage fibers.However, it is not possible to obtain ultra-high shrinkage polyester fibers that are effective for clothing using the above method alone. This is not possible, because even if the heat setting temperature during stretching is lowered, if a certain degree of strength is maintained, polyethylene terephthalate will only have a shrinkage rate of about 15 to 20%. Also, tertiary substances such as isophthalic acid and diethylene glycol. The shrinkage rate of polyethylene terephthalate copolymerized with the fourth component increases as the copolymerization ratio increases, and a spring water shrinkage rate of 70% is also possible. However, as the copolymerization ratio increases, the polymer's melting point decreases, and it becomes sticky and hard even in hot water, making it useless for clothing.

(Problems to be Solved by the Invention) The present invention improves the above-mentioned drawbacks, and has a highly shrinkage rate in spring water that is extremely high and does not undergo thermal agglutination or fusion in the normal manufacturing process of polyester mW products. This paper attempts to propose a shrinkable polyester fiber.

(Means for Solving the Problems) The highly shrinkable polyester fiber of the present invention is a core-sheath type polyester composite fiber, and the core portion in the cross section of the single filament contains 15 to 35 mol% of the glycol component. is polyethylene terephthalate (hereinafter abbreviated as PET) copolymerized with cyclohexaline methanol (hereinafter abbreviated as CHDM), the sheath is a polyester in which 88 mol% or more of the constituent units are ethylene terephthalate, and the core and It is characterized in that the composite ratio with the sheath part is 10=1 to 2:1.

The cross section of the high shrinkage polyester fiber of the present invention is
As shown in the figure, it is a core-sheath type composite fiber. The core is an ultra-high shrinkage component, and is PET in which 15 to 35 mol% of the glycol component is copolymerized with CHDM. The preferred copolymerization rate is 20~
It is 30 mol%.

If it is less than 15 mol%, the shrinkage will be small, and if it exceeds 35 mol%, the shrinkage will hardly change, and the sagging phenomenon (fusion of polymer granules) may occur when drying the polymer before spinning, which may cause trouble. This will result in a large number of The copolymerized PET of the core may be copolymerized with not only CHDM but also other diol components and dicarboxylic acids other than terephthalic acid, but 60 mol% or more of the constituent units may be composed of ethylene terephthalate units. desirable.

Examples of copolymerization components other than CHDM include diethylene glycol, triethylene glycol, tetramethylene glycol, and neopentyl glycol, and examples of dicarboxylic acids other than terephthalic acid include isophthalic acid, sodium sulfoisophthalate, naphthalene dicarboxylic acid, and the like.

PET copolymerized with 15 to 35 mol% CHDM exhibits an extremely large shrinkage rate when immersed in spring water when formed into fibers.However, many of these copolymerized PETs have lower melting points and softening points, and some Some polymers are completely amorphous and their melting points cannot be measured. And it may even form a stalemate during soaking in spring water.

Therefore, in order to use the CHDM copolymer PET as a fiber, the CHDM copolymer PET is used as a core, and a sheath having a relatively high melting point is formed surrounding the outer periphery of the core.

The polymer of the sheath portion is a polyester in which 88 mol% or more of the structural units are ethylene terephthalate. PET
Alternatively, if isophthalic acid, sodium sulfoisophthalate CHDM, diethylene glycol, triethylene glycol, etc. are less than 12 mol%, they may be copolymerized. A stalemate may occur during setting.

The composite ratio of core and sheath is 10:1-2;l. If the sheath ratio is too small, the stability of the cross-sectional shape of the composite spinning may deteriorate, and if the sheath ratio is too large, the shrinkability of the core will be impaired.

The single yarn fineness of the highly shrinkable polyester of the present invention can be selected according to the application, but 1 to 5 d is preferable for clothing applications.The cross-sectional shape is not only round, but also has triangular and square equicore sheath structures. If you can take it, you can choose freely.

(Example) Hereinafter, this will be explained in detail with reference to examples.

Example 1 A total of 100 parts of dimethyl terephthalate (hereinafter abbreviated as DMT), ethylene glycol and 1.4CHDM is 1
00 parts of various combinations of diols were mixed, put into a polymerization tank, and subjected to an esterification reaction using calcium acetate as a transesterification catalyst, and then 1,4-CHDMO copolymerization using antimony trioxide as a polymerization catalyst. Six types of CHDM copolymerization and copolymerization PE units with different ratios were prepared and each was made into chips. After vacuum drying these chips, they were combined with PET and composite spun. A core-sheath type composite fiber as shown in Fig. 1 with copolymerized PET as the core and PET as the sheath, the core:sheath composite ratio was 5:1, and the fineness after drawing was 70-d/24f. , six types of filaments were obtained with an elongation of 30%. Note that no heat centrifugation was applied during stretching. Chip drying conditions and spinning results Table 1 Spring water shrinkage percentages are values at a load of 2 mg/d.

From the above results, based on a shrinkage rate of 40% or more in spring water, the 1,4-CHDMO copolymerization rate in the core is 15 mol%.
The above is necessary, and in view of troubles during chip drying, it is found that a copolymerization rate of 35 mol % or less is appropriate.

Example 2 Bishydroxyethylene terephthalate and bishydroxyethylene isophthalate were appropriately mixed and subjected to condensation polymerization under vacuum in a polymerization tank, and the copolymerization rate of isophthalic acid was 4.8.
12.16 mol% of 4 types of isophthalic acid copolymerized PET
(P7 to P1°) was obtained and made into chips. After drying these chips, the CHDM 25 mol % copolymer PE copolymer PE color composite used in Example 1 was applied to form a core-sheath type composite fiber as shown in FIG. Spinning and drawing were carried out in the same manner as in Example 1. From the above results, it can be seen that it is preferable for the sheath polymer to be composed of 88 mol% or more of PET.

Example 3 CHDM 25 mol% copolymerized PET used in Example 1 (
P, ) and the 8 mol % isophthalic acid copolymerized PET (Ps) used in Example 2 were composite-spun to obtain core-sheath type composite yarns 50d/24f as shown in FIG. At this time, the composite ratio of the core and sheath was changed as appropriate. Spinning/drawing is Example 1
I did the same thing.

From this result, the composite ratio of the core and sheath is 2:1 to 10:1.
is good.

(Effects of the Invention) By using the highly shrinkable polyester fiber of the present invention, making it into a mixed yarn with other yarns, and performing a heat treatment or clean water treatment after weaving w1, a fabric with extremely high bulkiness can be obtained. In addition, the highly shrinkable polyester fiber does not stick to itself during the process, so it has the advantage that the texture does not become hard.

[Brief explanation of the drawing]

1 to 4 are examples of cross-sectional shapes of the highly shrinkable polyester fibers of the present invention.

Claims (1)

[Claims] (1) A core-sheath type polyester composite fiber, in which the core portion in the single fiber cross section contains 15 to 35 mol% of the glycol component.
is polyethylene terephthalate copolymerized with cyclohexaline methanol, the sheath is a polyester in which 88 mol% or more of the constituent units are ethylene terephthalate, and the composite ratio of the core and sheath is 10:1 to 2:1. A highly shrinkable polyester fiber characterized by: