JPH0770826A - Polyester composite fiber - Google Patents

Abstract

(57) [Summary] [Structure] It is composed of hot water-soluble polyester A and sparingly water-soluble polyester B, the composite ratio of polyester A and polyester B is 10/90 to 30/70, and the intrinsic viscosity of polyester A is The polyester conjugate fiber which is 0.56 to 0.70, and (the intrinsic viscosity of polyester A-0.03) <(the intrinsic viscosity of polyester B). [Effect] The polyester conjugate fiber of the present invention is excellent in various properties such as its own strength, yarn-forming property, weaving and knitting property, and quality of the woven and knitting product. If the splittable conjugate fiber is used, an ultrafine yarn can be obtained only by hot water treatment, and if it is a deformed cross-section fiber having a large degree of deformation, a woven or knitted fabric having a unique texture of natural silk can be suitably obtained. Further, it has a remarkable effect that it can be mixed with a natural fiber or the like that avoids a change due to a chemical treatment.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a composite fiber composed of a hot water-soluble polyester and a sparingly soluble hot water polyester, and the strength of the fiber after the hot water-soluble polyester of the composite fiber is dissolved and removed. The present invention relates to a composite fiber which is high and has excellent practical properties, and which can give a dry silky texture by specifying a cross-sectional shape.

[0002]

2. Description of the Related Art Conventionally, splittable conjugate fibers obtained by dividing an ordinary sparingly soluble polyester into a plurality of pieces with a soluble polyester have been widely used by taking advantage of the ability to obtain ultrafine fibers by dissolving and removing the soluble polyester. There is. It is also known that when a soluble polymer is dissolved and removed from a composite fiber in which the soluble polymer is arranged at a specific position on the fiber surface, a deformed cross-section fiber having a large degree of deformation which cannot be obtained by a usual spinning method can be obtained. There is.

[0003] Such a composite fiber is preferably applied with an alkali weight reduction process which is usually used in the field of polyester fiber woven and knitted fabrics as a dissolution and removal treatment of soluble polyester. As the soluble polymer, an alkali easily soluble polyester is used, and as the alkali easily soluble polyester, a polyester obtained by copolymerizing polyethylene terephthalate with 5-sodium sulfoisophthalic acid is generally used (for example, JP-A-54-6965, JP-B-62-
61686 gazette etc.).

On the other hand, for the above-mentioned composite fiber, a soluble polymer which is soluble only in hot water without using alkali has been proposed, but a polyester obtained by copolymerizing polyethylene terephthalate with 5-sodium sulfoisophthalic acid is also proposed. Is the basis (for example, Japanese Patent Publication No. 64-6286).

However, the soluble polyester obtained by copolymerizing 5-sodium sulfoisophthalic acid increases alkali copolymer solubility or hot water solubility with an increase in the copolymerization amount, but it becomes difficult to stretch in the stretching step and stretches. It is necessary to set the magnification low. Even in the case of the composite fiber containing the soluble polyester obtained by copolymerizing 5-sodium sulfoisophthalic acid as one component, the draw ratio must be set low similarly, so that the orientation of one poorly soluble component polymer in the drawing process. However, the strength of the composite fiber is low, and the strength of the fiber after the soluble polyester is dissolved and removed is also low. When the strength of the composite fiber is low, many yarn breakages and fluffs occur in the yarn making process and the weaving and knitting process, and not only the productivity but also the quality of the obtained woven and knitted product deteriorates. Further, when the strength of the fiber after the soluble polymer is removed by dissolution is small, the tear strength of the woven or knitted material is small, and in this respect also, the practicality is poor. In particular, in the case of a composite fiber in which a soluble polymer is arranged at a specific location on the fiber surface, if the strength of the deformed cross-section fiber obtained by dissolving and removing the soluble polyester is low, the deformation of the cross-sectional shape due to fibrillation or external force becomes large. However, the drawbacks derived from this increase, resulting in a further impracticality.

[0006]

DISCLOSURE OF THE INVENTION The present inventors have found that a composite fiber composed of a hot water-soluble polymer and a sparingly hot water-soluble polymer has a drawback that its strength is small, and consequently, a soluble polymer, particularly a hot water-soluble polymer. The strength of the fiber after dissolution and removal is low, and further, when the hot water-soluble polymer is dissolved and removed to form a deformed cross-section fiber, deficiencies such as fibrillation and easy deformation of the cross-sectional shape are formed. It was found that this can be improved by optimizing the composition of the polymer. That is, the object of the present invention is not only to dissolve and remove soluble polymers, especially hot water-soluble polymers, and to exert the functions and effects based on the dissolution treatment,
An object of the present invention is to provide a polyester conjugate fiber having sufficient practicability such as weaving and knitting property (so-called process passing property) and quality of woven and knitting product.

[0007]

The above object of the present invention is a composite fiber composed of a hot water-soluble polyester A and a sparingly soluble hot water polyester B, in which the composite ratio of polyester A and polyester B (weight: Ratio) is 10/90 to 30
/ 70, the intrinsic viscosity of polyester A is 0.56 to 0.7
0 and (intrinsic viscosity of polyester A-0.03) <
(Intrinsic viscosity of polyester B), which can be achieved by a polyester conjugate fiber.

That is, the polyester conjugate fiber of the present invention comprises a hot water-soluble polyester A and a hot water sparingly soluble polyester B. At least a part of each segment formed of the hot water-soluble polyester A forms the surface of the composite fiber, and the segment is arranged so as to be easily removed in the hot water dissolution treatment. It may be a cross-sectional shape such as a composite fiber arranged at a specific location. Moreover, in the conjugate fiber in which the polyester A is arranged at a specific portion on the fiber surface, the effect of the present invention is easily exerted when the polyester A is dissolved and removed to obtain a deformed cross-section fiber having a large degree of deformation. If a plurality of composite fibers having a cross-sectional shape that are tapered segments from the surface of the fiber toward the inside of the fiber are present, it is possible to obtain a woven or knitted fabric which has a silky dry feel and a silky texture.

1 and 2 show polyester A (in the drawings,
1) shows the cross-sectional shape of the composite fiber of the present invention in which 3) are present as tapered segments from the surface of the fiber toward the inside of the fiber, and the remaining part is composed of polyester B (2 in the figure). As the shape of the whole fiber, Fig. 1 shows a round cross section,
FIG. 2 is a trilobal cross section. When the conjugate fibers of FIGS. 1 and 2 are subjected to hot water treatment to dissolve and remove the polyester A, the deformed cross-section yarns having a large degree of deformation shown in FIGS. 3 and 4, respectively, can be easily obtained.

Next, the polymer composition constituting the composite fiber of the present invention will be described. That is, the polyester A is soluble in hot water and the polyester B is sparingly soluble in hot water.

The hot water-soluble in the present invention means the property of being substantially dissolved in an ordinary aqueous solution at 98 ° C., and the sparingly soluble in hot water is the property of not being substantially dissolved under the above-mentioned conditions. Means there is.

The polyester A contains 5% as the third component.
-A copolyester obtained by copolymerizing sodium sulfoisophthalic acid with polyethylene terephthalate can be preferably used, but a copolymerization of only 5-sodium sulfoisophthalic acid requires a large amount of copolymerization and is stretched as described above. It may be difficult to do so. In order to easily stretch the polyester A and improve the hot water solubility, it is desirable to copolymerize the fourth component with the third component. Among the fourth components, the spinnability is not reduced,
In addition, isophthalic acid can be preferably used because it can efficiently improve hot water solubility. That is, as the polyester A, a copolymer obtained by copolymerizing 5-sodium sulfoisophthalic acid as a third component in an amount of 8 to 14 mol% and isophthalic acid as a fourth component in an amount of 10 to 33 mol% with ethylene terephthalate as a main constituent component is used. It is preferably a polymerized polyester. When the copolymerization amount of 5-sodium sulfoisophthalic acid is less than 8 mol%, the hot water solubility is lowered, and when it is more than 14 mol%, the strength of the composite fiber is apt to be lowered, and it is easily dissolved even in cold water. It may be difficult to handle in the yarn making and higher order processes. Further, if the copolymerization of isophthalic acid is less than 10 mol%, the solubility in hot water is lowered, or insoluble matter is liable to remain during the dissolution treatment.
If the amount is larger, it is difficult to obtain sufficient spinnability, which may cause defects such as a decrease in strength of the composite fiber.

On the other hand, the polyester B is preferably a polyester having an ethylene terephthalate unit of 80 mol% or more, and more preferably a polyester substantially composed of ethylene terephthalate.

The composite ratio (weight ratio) of the polyester A and the polyester B must be 10/90 to 30/70. The range is preferably 12/88 to 25/75. If the composite ratio is less than 10/90, the spinnability is deteriorated, and if it is more than 30/70, the strength of the composite fiber is decreased.

The intrinsic viscosity of polyester A is 0.
It should be 56 to 0.70. Preferably 0.56
Is about 0.68. If the intrinsic viscosity is smaller than 0.56, the spinnability becomes insufficient, and if it is larger than 0.70, the strength of the composite fiber becomes small.

[(Intrinsic viscosity of polyester A-
0.03) needs to be smaller than (intrinsic viscosity of polyester B). It is preferably (intrinsic viscosity of polyester A−0.01) <(intrinsic viscosity of polyester B). If the intrinsic viscosity of the polyester A deviates from this range, the strength of the composite fiber after hot water treatment will decrease,
This causes defects such as increased yarn breakage and fluffing in the weaving and knitting process, which not only reduces productivity but also deteriorates the quality of the woven and knitted fabric obtained by high-order processing of the fibers.

The intrinsic viscosity of polyester B is 0.60
The range of 0.75 is preferable for maintaining the fiber performance.

The intrinsic viscosity of each polyester referred to in the present invention is a value obtained by a conventional method in orthochlorophenol at 25 ° C.

[0019]

EXAMPLES The present invention will be specifically described below with reference to examples. Example 1 Ethylene terephthalate as hot water soluble polyester A
12 mol% of 5-sodium sulfoisophthalic acid,
25 mol% of isophthalic acid was copolymerized to prepare a copolyester having three intrinsic viscosities shown in Table 1. As the hot water sparingly soluble polyester B, polyethylene terephthalate having an intrinsic viscosity of 0.64 was prepared. Using the spinneret shown in Japanese Patent Publication No. 62-6186 for both polymers, a composite ratio of 15/85 (weight ratio) was used to spin the composite fiber of 75 denier 36 filaments shown in FIG. Habutae was woven from this fiber by a conventional method, and then hot water treatment was performed to elute and remove the polyester A component.

Strength of the obtained composite fiber before and after hot water treatment,
Table 1 shows the yarn-forming property, the weaving property, and the fabric quality. As shown in Table 1, the standard NO. 1
Had small strength-related properties, and the process passability and fabric quality were also poor. On the other hand, the level No. given as an example of the present invention. Nos. 2 and 3 are good in strength relation, processability, and woven fabric quality. 3 was excellent.

Next, the obtained woven fabric was dyed in dark blue, made into a blouse, and subjected to a wearing test for a total of 10 days. In No. 1, the elbow portion was whitened by frosting, and a remarkable deformation of the cross-sectional shape was recognized. On the other hand, in the table,
Level No. No. 2 has some frosting on the elbows, but it is level No. 2. No defects such as frosting were observed in No. 3 at all.

[0022]

[Table 1] Example 2 As the hot water-soluble polyester A, a copolyester having the same composition as in Example 1 and an intrinsic viscosity of 0.62 was prepared.
As the hot water sparingly soluble polyester B, polyethylene terephthalate having an intrinsic viscosity of 0.66 was prepared. The composite ratio was changed to 7 levels as shown in Table 2, and according to Example 1, composite spinning was performed, weaving, and elution treatment. As shown in Table 2, in the levels 4 and 10 given as comparative examples of the present invention, the level 4 has poor spinnability, and the level 10 has small strength-related properties, process passability and textile quality are also poor. It was On the other hand, the level No. given as an example of the present invention. The above-mentioned defects were not recognized in Nos. 6-8 was excellent.

[0023]

[Table 2]

[0024]

Industrial Applicability The polyester conjugate fiber of the present invention is a conjugate fiber composed of a hot water-soluble polymer and a sparingly hot water-soluble polymer, and the composition and amount of the polymer constituting the fiber are optimized. Has good spinnability, and the strength of the fiber itself is high. Consequently, the weaving and knitting properties of the composite fiber and the practical properties such as the quality of the woven and knitting product are excellent. Further, since the hot water-soluble polymer can be easily removed by the hot water treatment, it is possible to obtain an ultrafine yarn only by the hot water treatment if the splittable conjugate fiber is used, and the hot water soluble polymer is arranged at a specific position. When the composite fiber is used, it becomes a deformed cross-section yarn having a large degree of deformation only by hot water treatment, and a woven or knitted fabric having a unique texture of natural silk can be suitably obtained. Further, since the composite fiber is dissolved and removed by hot water treatment and does not require a special chemical treatment, it can be sufficiently mixed with many other types of fibers, especially natural fibers that are repelled by the change due to chemical treatment. It has a remarkable effect in the field of woven and knitted fabrics.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a circular cross-section composite fiber according to an example of the present invention.

FIG. 2 is a schematic cross-sectional view of a trilobal cross section composite fiber according to another example of the present invention.

FIG. 3 is a schematic cross-sectional view of a round cross-section fiber obtained after heat treatment of the fiber of the present invention (FIG. 1).

FIG. 4 is a schematic cross-sectional view of a deformed cross-section fiber having a large degree of deformation obtained after heat treatment of the fiber of the present invention (FIG. 2).

[Explanation of symbols]

 1: Hot water soluble polymer 2: Hot water sparingly soluble polymer

Claims (2)

[Claims] 1. A composite fiber composed of hot water-soluble polyester A and sparingly soluble hot water polyester B, wherein the composite ratio of polyester A and polyester B is 10/90 to.
30/70, intrinsic viscosity of polyester A is 0.56 ~
0.70, and (intrinsic viscosity of polyester A-0.0
3) Polyester composite fiber, wherein <(intrinsic viscosity of polyester B). 2. The polyester conjugate fiber according to claim 1, wherein a plurality of polyesters A are present in the cross section of the conjugate fiber as a segment having a taper shape from the fiber surface toward the inside of the fiber.