JPS61174415A - Composite fiber bundle and production thereof - Google Patents

Abstract

PURPOSE:To produce a composite fiber bundle having soft feeling and high stretchability, by drawing a multi-layer laminated composite spun yarn having a specific flatness and composed of elastic polymers and non-elastic polymers laminated alternately along the direction of fiber axis, and separating the elastic polymers from the non-elastic polymers in the drawn fiber. CONSTITUTION:A composite spun fiber which is a multi-layer laminated fiber composed of elastic polymers and non-elastic polymers laminated alternately along the direction of the fiber axis and having an average flatness (L/W) of each layer of >=2 (L and W are the maximum length and the maximum width of each layer in the cross-section of the fiber), is drawn 1.5X4.5 times, and the elastic polymer component is separated from the non-elastic polymer component to obtain the objective fiber bundle wherein the ratio of the length of a non-elastic polymer fiber to that of the elastic polymer fiber existing continuously in a fiber bundle of a definite length is 1.2-3.8.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a composite fiber bundle that is soft and has high elasticity and is made of elastic fibers with a flat cross section and inelastic fibers that are also flat in cross section, and a method for manufacturing the same. It is something.

[Conventional technology]

Conventionally, composite fiber bundles consisting of fibers with a flat cross section are
All of them are known to consist only of inelastic fibers, but
Naturally, such composite fiber bundles are not highly elastic. Furthermore, core spun yarns and covered yarns with rubber or spandex cores are known as composite fibers of elastic fibers and inelastic fibers. . However, such composite fibers have a high flexural modulus and are inferior in elasticity.

[Problem that the invention seeks to solve]

In recent years, there has been a remarkable development of fibers with special properties. The present inventors conducted research on a material that is soft at the waist and rich in elasticity as a material with new performance.
Cover yarns using conventional flat fibers or conventional elastic fibers did not satisfy the above performance.

Although conventional flat fibers have a softer waist than those with a circular cross section, they generally do not have elasticity because they use inelastic fibers.

In addition, conventional Kapaya, which is a combination of elastic fibers and inelastic fibers, has a circular or nearly circular cross section, so it has high bending elasticity and is advantageous for having a soft waist. It has not been done.

[Means to solve the problem]

The present inventors have arrived at the present invention as a result of intensive research aimed at developing a composite fiber bundle that is soft and highly elastic as a new material.

That is, the present invention provides a fiber bundle consisting of elastic fibers and inelastic fibers, and the elastic fibers and inelastic fibers have a flatness L/W (
L and W are flat fibers with an average value of 2 or more in the maximum length and maximum width of the fiber cross section, respectively, and the average value of each elastic fiber continuously present in a fiber bundle of a certain length. The ratio of the real length of one inelastic fiber to the real length is 1.
2 to 3.8, and as a method for obtaining such a composite fiber bundle, a multilayer laminated fiber in which elastic polymers and inelastic polymers are alternately laminated in the fiber axis direction, And the flatness of each layer L/W (L.

W is 165 to 4 for composite spun fibers whose average values (maximum length and maximum width of each layer in the fiber cross section) are 2 or more.
．． This is a method for producing a composite fiber bundle, which is characterized in that the elastic polymer component and the inelastic polymer component are separated after being stretched five times.

The reason why the product of the present invention has a soft waist and high elasticity is explained as follows. According to the teachings of structural mechanics, the bending elasticity of materials with the same cross-sectional area is smaller if the cross-sectional structure is flat than if it is circular, resulting in what is called "softer material." That is, by making the cross-sectional structure of yarns of the same denier flat, the bending elasticity in the flat direction can be significantly reduced with almost no loss in strength or elongation. Furthermore, since flat fibers tend to tangle together less easily, when combined with elastic fibers, stretch elasticity recovery is good and a soft product can be obtained. That is, even if a hard inelastic polymer such as polyester or polypropylene is made into a thread having the above-mentioned cross section, a reasonably soft thread can be obtained.

On the other hand, if you make thread from an elastic polymer such as polyurethane,
It is a well-known fact that products with extremely high elongation can be obtained. The present inventors have discovered that a composite fiber bundle obtained by combining the above-mentioned characteristics as a fiber composite having a soft waist and high elasticity satisfies the above-mentioned required performance.

If an elastic polymer (component A) and an inelastic polymer (component B) are combined and composite-spun and stretched under conditions where component B is sufficiently oriented, component A will be temporarily fixed by component B in the stretched, so-called tension state. ◇If the yarn in which the A component is temporarily fixed in a tensioned state by the B component is treated with mechanical force such as crimping or with a solvent or heat, the A component and B component can be produced. are separated, the A component is released from the temporary fixation by the B component, the tension in the A component is released, and the A component contracts. The B component becomes loose due to the contraction of the A component in the east direction of the fiber. If elongation stress is applied to the shrunken fiber bundle obtained in this way, it can be elongated with extremely low stress based on the elasticity of the human component, at least until the temporarily fixed state before shrinkage occurs, and Since there is little entanglement between the A and 8 fibers and the inelastic fibers after splitting, the elastic recovery properties are extremely excellent, resulting in 9 fibers.

Furthermore, since both the A component fiber and the B component fiber have a flattened cross section after division, they have a so-called "flexible" property with a low bending modulus.

The elastic polymer used in the present invention is preferably polyurethane, but ester elastomers and the like can also be used.

Further, as the inelastic polymer, polymers that can be used as ordinary fibers such as polyester, polyolefin, and polyamide can be used. In addition, the elastic polymer referred to in the present invention means a polymer that has an elongation elastic recovery rate of 90% or more after 1 minute when the polymer is formed into a fiber and the fiber is stretched by 50% at room temperature. . In addition, the elongation elastic recovery rate measured in the same manner as inelastic polymer is 50.
-Limited elongation of less than 50% at room temperature
It means something less than. In the present invention, it is preferable that the average flatness (L/W) of the elastic fibers and the inelastic fibers be 2 or more in order to keep the bending modulus small. The degree of flatness can be freely selected depending on the shape of the hole in the spinneret.

In addition, the ratio (tB/8) of the actual length tB of one inelastic fiber to the length tA of one elastic fiber existing in the eastward direction of fibers of a constant length (tB/8) is 1.2 to 3.
．． It is preferable that the number is 8 in order to impart extensibility and elongation recovery to the fiber. tB/lA can be freely changed by adjusting the stretching ratio before peeling. 1.2-3 above.
In order to obtain a value within the range of 8, the method of the present invention uses a method in which undrawn yarn is drawn at a draw ratio of 1.5 to 4.5 times. Note that the actual length referred to in the present invention is the length of the fiber measured along the bend of the fiber. The fiber bundle of the present invention is suitable as a pargy yarn for producing stretchable fabrics. The resulting stretchable fabric is used for bandages, supports, etc.

Example I As the A component, polyurethane obtained by melt polymerization from polytetramethylene ether glycol, bishydroxyethoxybenzene, and 4,4'-diphenylmethane diisocyanate with an average molecular weight of 1350 was used, and as the B component, polypropylene was used, and the weight ratio was A. :B=40 :60
The mixture was fed into a spinning machine equipped with a multilayer yarn spinning nozzle (30 holes) at a ratio of 100 to 200 mm, and the spinning head was heated to 220° C. and spun to obtain a 14 denier multilayer composite yarn. This multilayer composite yarn had a cross-sectional shape in which the A component and the B component were alternately laminated in 5 layers and 6 layers, respectively.

This yarn was subjected to wet heat stretching at 40° C. by a factor of 2.9 to obtain a multilayer composite filament. This filament is immersed in perchloren at 30°C to separate the A and B components, and at the same time
The components were caused to shrink and the solvent was dried to obtain a composite fiber bundle. The L/W of both the elastic fibers and inelastic fibers constituting this fiber bundle was about 10. Also, tθ of this fiber bundle
8 was 2.5.

This fiber bundle was very soft and highly elastic. Compared to the fiber before the A and B components were peeled off, the initial Young's modulus was approximately I, and the elongation was approximately 2.5 times higher, indicating that a soft and highly elastic fiber was obtained. it is obvious.

Example 2 As component A, polytetramethylene glycol with an average molecular weight of 1500 ft, 1.4-butanediol and 4.4
Polyurethane obtained by melt polymerization from '-diphenylmethane diisocyanate was fed into a spinning machine equipped with a multilayer spinning nozzle (30 yt Neil) using polybutylene terephthalate as component B at a weight ratio of 50:50, and spinning. Spinning with a head temperature of 220℃ 1
A multilayer composite yarn of 8 denier was obtained. This multilayer composite yarn is A
It had a cross-sectional shape in which five layers and six layers of component B and component B were laminated alternately, respectively.

This yarn was drawn under wet heat at 50°C by a factor of 2 to 3 to obtain a multilayer composite filament. The filament was immersed in a mixed solvent of equal weights of percrene and chloroform at 30°C to separate the A component and the B component, causing the A component to shrink, and the solvent was dried to obtain a composite fiber bundle. This item was extremely soft and highly elastic. The L/W of both the elastic fibers and inelastic fibers constituting this fiber bundle was approximately 10. Also, l-a/lh of this fiber bundle is 'L
I missed it at 8.

Example 3 A polyurethane obtained by melt polymerizing polybutylene adipate, 1,4-butanediol and 4,4'-diphenylmethane diincyanate having an average molecular weight of 1000 as the A component, and polypropylene as the B component, A multilayer composite filament was obtained in the same manner as in Example 1 with a ratio of A:B=45:55.

This filament is applied to a crimper to separate the A component and the B component, and at the same time cause the A component to shrink, forming a composite fiber bundle 'f! :Obtained. The structure and physical properties of this product were similar to those of Example 1.

Claims (1)

[Claims] 1. A fiber bundle consisting of elastic fibers and inelastic fibers, wherein the elastic fibers and the inelastic fibers have an oblateness L/W (L and W are the maximum length and maximum width of the fiber cross section, respectively). ) is a flat fiber with an average value of 2 or more, and the actual length of one inelastic fiber compared to the actual length of one elastic fiber that exists continuously in a fiber bundle of a certain length. A composite fiber bundle having a ratio of 1.2 to 3.8. 2. It is a multilayer bonded fiber in which elastic polymers and inelastic polymers are alternately laminated in the fiber axis direction, and the flatness of each layer is L/W (L and W are the maximum lengths of each layer in the fiber cross section, respectively). Manufacture of a composite fiber bundle characterized by stretching composite spun fibers having an average value of 2 or more (maximum width) by 1.5 to 4.5 times, and then separating an elastic polymer component and an inelastic polymer component. Method.