JPS6366942B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing surface-modified polyester composite fibers having grooves (hereinafter also referred to as groups) extending substantially perpendicular to the direction of the fiber axis. Polyester fibers have very good properties as clothing fibers, but because they are generally formed by melt spinning, they also have the same characteristic of having a smooth surface as other synthetic fibers made by melt spinning. have This characteristic of having a smooth surface is one of the characteristics that differs greatly from that of natural fibers, and is one of the reasons why the texture, luster, and depth of color when dyed are different from those of natural fibers. There is. Therefore, many surface modifications have been proposed and implemented to bring the surface morphology of polyester fibers closer to that of natural fibers. These conventional surface modifications are broadly classified into physical surface modification and chemical surface modification. and,
Physical surface modification mainly involves grinding with a grinder and heat forming method, while chemical surface modification involves solvent treatment, in which different components such as easily soluble are blended into the polyester fiber in advance depending on the purpose. There are things being done. Table 1 shows the surface modification forms obtained by such conventional surface modification methods.

[Table] That is, as is clear from Table 1, none of the conventional polyester fibers had groups on the surface in a direction perpendicular to the fiber axis, similar to the scale of wool. The reason why indentation crimping was selected as a heat forming method for physical surface modification is because although it is a crimp imparting method, it has a relatively large surface modification effect. Methods of creating indentations in the right angle direction have been proposed, but these are not practical methods that provide an effective effect, and methods that use heat dies or heated rolls such as a modified spinneret, or false twist crimp methods cause the surface to deform. However, this is due to cross-sectional deformation and the surface modification effect is small. The present invention provides a novel method for producing polyester fibers having groups on the surface in a direction perpendicular to the fiber axis. In order to maintain sufficient strength to withstand use even with groups, the structure of the sheath-core composite fiber is such that there is a core area where groups do not form and a surface area where groups form. It's on. In the present invention, a sheath-core composite fiber made of two types of polyesters having different resistances to amine solvents and having a polyester having a low resistance to the solvents arranged on the surface is treated with the solvent, and the sheath is A method for producing a surface-modified polyester composite fiber, characterized in that grooves are formed in a direction substantially perpendicular to the fiber axis on the surface of the polyester. The method of the present invention is a method of treating a sheath-core type composite fiber in which a polyester having low resistance to amine solvents is arranged in the sheath part and a polyester having high resistance in the core part, with an appropriate solvent. As polyesters that have high resistance to amine solvents for sheath-core composite fibers, homopolyesters with a higher intrinsic viscosity than those that satisfy the physical properties required when made into ordinary drawn fibers are mainly used. However, copolymerized polyesters may also be used, and in that case, polyesters with a small copolymerization ratio are preferred. Further, as the polyester having low resistance to amine solvents, homopolyesters having a low intrinsic viscosity and copolymerized polyesters having a high copolymerization ratio are used, contrary to the above-mentioned polyesters. In other words, when these two types of polyesters are used, the polyester with a high intrinsic viscosity or a low copolymerization ratio shows great resistance to amine solvents, and the polyester with a low intrinsic viscosity or a high copolymerization ratio shows great resistance to amine solvents. Polyester will exhibit less resistance. The sheath-core composite fibers are formed using conventionally known spinning and drawing methods. Solvents for treating such sheath-core composite fibers include monomethylamine, monoethylamine,
Aqueous solutions of alkylamines such as n-propylamine and butylamine, aqueous solutions of hydrazine hydrate, and the like are used. Although the mechanism of polyester decomposition reactions caused by these solvents has not yet been clearly elucidated, amorphous regions exist in the polyester formed into fibers due to the influence of residual stress, and the diethylene glycol component in the polyester is alkyl. Since it is mostly distributed in amorphous regions that are easily penetrated by solvents such as amines, it is thought that solvents such as alkylamines selectively decompose the amorphous regions to form groups. Furthermore, although the reason why the above-mentioned groups occur in the direction perpendicular to the fiber axis is not clear, it seems that defects or amorphous parts in the macroscopic structure of the polymer are concentrated in the direction perpendicular to the fiber axis due to fiber formation. As a result, the concentration is distributed regularly in the direction of the fiber axis, and the distributed concentrated portion is selectively decomposed from the outside by the amine solvent. As a result, the groups in the direction perpendicular to the fiber axis are It is thought that they occur side by side in the axial direction. As mentioned above, it has been explained that groups perpendicular to the fiber axis are formed in the polyester sheath, which has low resistance to amine solvents, and are aligned in the fiber axis direction. The pitch of the directional alignment depends on the fine structure of the fibers, which varies depending on the type of polyester and fiber formation conditions, the type of amine solvent, treatment concentration, treatment temperature, etc.
It varies depending on processing conditions such as processing time. In addition, the core polyester, which has high resistance to amine solvents, can be made to have almost no such groups and be given strength, and the selection of two types of polyester and the fiber By appropriately setting the formation conditions and producing an eccentric sheath-core type composite fiber, it is also possible to obtain a fiber that is even more crimpable. By causing crimp to occur in this manner, the polyester composite fiber obtained by the method of the present invention will exhibit performance more similar to wool. In other words, by appropriately selecting the two types of polyester in the sheath-core composite fiber, the fiber forming conditions, the solvent treatment conditions, etc., the surface of the sheath polyester, which has low resistance to amine solvents, is coated at right angles to the fiber axis. It is possible to obtain a fiber having sufficient strength, in which groups in the same direction are arranged in the direction of the fiber axis, and furthermore, it is possible to obtain a fiber having latent crimp. In addition, if the sheath-core composite fiber is made of polyester and a polymer other than polyester, it is easy to select one that has a large difference in resistance to amine solvents and heat shrinkage after fiber formation. In this case, the excellent properties of polyester fibers are diminished, and in general, combinations of polyester and polymers other than polyester have poor compatibility and are easily peeled off, resulting in the disadvantage that the surface modification effect is not exhibited. In this regard, the present invention was made based on the discovery that groups in the direction perpendicular to the fiber axis that provide a sufficient surface modification effect can be obtained even with sheath-core composite fibers made of polyester. The surface-modified composite fiber thus obtained also has the feature of excellent durability in that the surface having groups does not fall off. As already mentioned, the groove width, depth, and pitch of the group grooves in the composite fiber obtained by the method of the present invention in the axial direction of the fibers depend on the resistance of the polyester to amine solvents, fiber formation conditions, and solvent treatment. Although it varies depending on the conditions,
The groove width of the group is mainly influenced by the solvent treatment conditions, followed by the type of polyester and fiber formation conditions, the depth is strongly influenced by the solvent treatment conditions, and the pitch of the rows is influenced by the polyester. It has been established that the type and fiber formation conditions are dominant. Therefore, if the strength of the influence of these conditions is considered, fibers with different group groove widths, depths, and arrangement pitches can be obtained with considerable freedom. Therefore, regarding various sheath-core type composite fibers with different thicknesses of polyester in the sheath part, which has low resistance to amine solvents, we investigated the problem of using fibers with different groove widths, depths, and pitches perpendicular to the fiber axis on the surface of the polyester in the sheath part. As a result of making and examining various products with groups in the same direction, we found that, where the diameter of the composite fiber is D, the thickness of the polyester in the sheath is in the range of 0.05D to 0.5D.
The groove width of each group is in the range of 0.01D to 1.0D, the depth is in the range of 0.01D to 0.5D, and the pitch in the fiber axis direction is in the range of 0.01D to 10.0D. It was found that this material is preferable because it has an excellent surface modification effect and also has sufficient fiber strength. In other words, since the thickness of the polyester in the sheath is related to the maximum depth of the group, if it is thinner than 0.05D, the depth of the group will be shallower than 0.01D in many cases, and the group effect will no longer appear.
When the composite fibers become almost only sheath parts and the depth of the group reaches 0.5D, the fiber strength decreases and the fiber becomes unusable. Also, the groove width of the group
If it is smaller than 0.01D, the group effect will not appear, and if it is larger than 1.0D, the group effect will be diminished and the fiber strength will also decrease.
Furthermore, the pitch of the group arrangement is also related to the groove width and depth, but if it is smaller than 0.01D or larger than 10.0D, the effect of the group will be diminished. and,
If the group groove width, depth, and alignment pitch are within the ranges mentioned above, for example, if the groove pitch is coarse depending on the type of polyester and fiber forming conditions, the groove width and depth may vary depending on the solvent treatment conditions. When the depth is increased, the effect of the group can be made to appear by complementing each other. Depending on the type of polyester and fiber formation conditions, groups in the direction perpendicular to the fiber axis may occur as well as groups in the direction perpendicular to the fiber axis. The surface modification effect is exhibited. In addition to the amine-based solvent treatment that causes the surface-modified composite fibers obtained by the method of the present invention to form groups, the surface-modified composite fibers obtained by the method of the present invention may also be treated with other solvents, such as alkaline treatment, to generally roughen the surface. It may be something that has undergone or is about to undergo treatment. Hereinafter, the present invention will be explained based on examples. Example 1 Polyethylene terephthalate with an intrinsic viscosity of 0.400 was used as the sheath, and polyethylene terephthalate with an intrinsic viscosity of 0.640 was used as the core. Spinning was carried out at a melting temperature of 290°C so that the weight ratio of the sheath and core was 1:2. speed
A yarn made of composite fiber was produced at 3000 m/min, and the yarn was subjected to false twisting and crimping to obtain a crimped yarn. The crimped yarn was twisted in a range of 200 to 300 T/M and woven to produce a textured yarn fabric. The processed yarn fabric was immersed in a 60% monoethylamine aqueous solution at 30° C. for 12 hours, then washed with ethyl alcohol, washed with water, and dried to obtain a treated fabric. This treated fabric had a texture more similar to wool than the processed yarn fabric before monoethylamine treatment. The surface of the composite fibers of the crimped yarn that makes up this treated fabric has a groove width of approximately 0.5.
-1.0μ, depth of about 2-5μ in the direction perpendicular to the fiber axis, the groups were lined up in the direction of the fiber axis with a pitch of about 5-8μ. Example 2 Sodium, sulfo, isophthalic acid component: 2.6
Mol% copolymerized polyethylene terephthalate with an intrinsic viscosity of 0.485 is used in the sheath, and the inner viscosity is 0.640.
of polyethylene terephthalate becomes the core, and the melting temperature is adjusted so that the weight ratio of the sheath and core is 1:2.
The yarn was spun at 290°C and drawn to make a composite fiber yarn, and this yarn was used to make woven and knitted fabrics. The woven and knitted fabrics were each immersed in a 40% monoethylamine aqueous solution at 30°C for 10 hours, then washed with ethyl alcohol, water, and dried. The obtained woven and knitted fabrics had a special dry-touch feel that was different from the woven and knitted fabrics before being treated with monoethylamine. In addition, in the composite fibers of the constituent threads of the woven and knitted fabrics treated with monoethylamine, groups in the direction perpendicular to the fiber axis were formed on the surface of the composite fibers, aligned in the direction of the fiber axis.

Claims (1)

[Claims] 1. A sheath made of two types of polyesters with different resistances to amine solvents and having a polyester with low resistance to the solvents arranged on the surface.
A surface-modified polyester conjugate fiber characterized in that the core-type conjugate fiber is treated with the solvent to form grooves in a direction substantially perpendicular to the fiber axis on the surface of the polyester of the sheath portion, which are lined up in the direction of the fiber axis. Production method.