Differing-shape side-by-side composite cross-section fiber, and production methods for fabric and differing-shape cross-section fiber using same

Abstract

Provided is a differing-shape side-by-side composite cross-section fiber which comprises two types of polymers having differing glass transition points and in which the cross-sectional shapes of polymer components differ, wherein X / Y, which is the ratio of the polymer-to-polymer distance X between the centers of the smallest circles enclosing the respective differing-shape cross-sections of the polymer components to a bonding surface length Y in a cross-section, is not less than 1.1. The polymer components are preferably a polyamide polymer and a copolymer polyester polymer, and the cross-sectional shapes thereof preferably have at least two protruding shapes. The present invention also encompasses a production method for a differing-shape cross-section fiber using the differing-shape side-by-side composite cross-section fiber, and a production method for a fabric which has both a fine chambray effect and wear resistance.

Description

Modified side-by-side composite cross-section fiber, and method for manufacturing modified cross-section fiber and fabric using the same

[0001] The present invention relates to a modified side-by-side composite cross-section fiber that is excellent in processability, and a method for producing a modified cross-section fiber and fabric using the same that have a good texture and a unique appearance.

[0002] Many technological developments have been made in side-by-side composite cross-section fibers (hereinafter sometimes referred to as "composite fibers"), and they are widely used industrially. Among them, many types of composite fibers made of polyester polymers and polyamide polymers have been developed, due in part to the ease with which the polymers are available. For example, copolymer polyesters containing sulfoisophthalic acid as the polyester polymer are known to be a good combination with excellent cross-sectional formability, as the sulfonate groups of the polyester polymer and the amide groups of the polyamide polymer adhere electrostatically well. Many cross-sectional shapes have also been proposed, including sea-island cross-sections, side-by-side composite cross-sections, and pie-type split composite cross-sections.

[0003] For example, Patent Document 1 discloses moisture-sensitive crimped conjugated fibers in which copolymerized polyethylene terephthalate having sulfonate groups and polyamide containing polyalkylene glycol are bonded side-by-side, and the fibers have latent crimp development, which allows the crimp rate to change reversibly with changes in humidity. However, these conjugated fibers are used using a technology in which both components remain bonded, and the bonded surface is long, so it is not anticipated that the fibers will be split later.

[0004] On the other hand, as a technique for splitting a composite fiber after spinning, for example, Patent Document 2 discloses a method for producing a mixed yarn in which a crimped yarn is used as it is and the two components are split by a mild alkaline aqueous solution treatment. However, Patent Document 2 relates to a composite fiber of a copolymer polyester and polyamide 46 or a polyamide containing nylon 46 as the main component, and the splitting method utilizes the poor affinity between nylon 46 and the copolymer polyester, and is based on the alkaline aqueous solution treatment. However, there is a problem that the spinnability is deteriorated due to the large difference in melting points between nylon 46 and the copolymer polyester, and the texture is not superior to that of a mixed yarn produced by the conventional method in which the two components are separately spun.

[0005] Furthermore, Patent Document 3 proposes a side-by-side type composite fiber of a copolymer polyester and a polyamide, which is cost-effective, has excellent spinnability, and is easy to split in a post-process. However, the shape of the disclosed fiber is a cocoon-like shape in which two circular cross sections are joined together, and the fibers after splitting also have an approximately circular cross section, and it does not have an advantage in terms of texture over fibers made by conventional methods in which the two components are separately processed into fibers.

[0006] Furthermore, with regard to fabrics using such fibers, consumer needs are diversifying, particularly in the field of sportswear, and products that not only have functionality but also new appearances and textures are being sought. However, when known composite fibers are used, the fibers made up of multiple components are not mixed sufficiently uniformly, resulting in problems such as a poor color effect and a poor chambray feel.

[0007] JP 2003-239140 A JP 63-92721 A JP 2018-59253 A

[0008] An object of the present invention is to provide an irregular side-by-side composite cross-section fiber that can be easily split in a post-spinning process and becomes an irregular cross-section fiber with excellent texture, and a method for producing an irregular cross-section fiber and fabric using the same.

[0009] In order to solve the above problems, the following inventions are provided. 1. An irregular side-by-side composite cross-section fiber made of two polymers with different glass transition points, the cross-sectional shapes of the polymer components being irregular, characterized in that X / Y, the ratio of the inter-polymer distance X connecting the centers of the smallest encompassing circles of the irregular cross-sections of the polymer components to the joint surface distance Y in the cross-section, is 1.1 or more. 2. An irregular side-by-side composite cross-section fiber as described above in 1, in which the cross-sectional shape of the polymer components has two or more protrusion shapes on the joint surface of each polymer. 3. An irregular side-by-side composite cross-section fiber as described above in 1 or 2, in which the irregular side-by-side composite cross-section fiber is a crimped fiber. 4. An irregular side-by-side composite cross-section fiber as described above in any one of 1 to 3, in which the two polymers are a polyamide polymer and a copolymerized polyester polymer. 5. An irregular side-by-side composite cross-section fiber as described above in 4, in which the polyamide polymer is a nylon 6 polymer. 6. 6. The fiber according to claim 4 or 5, wherein the copolymerized polyester polymer is a sodium sulfoisophthalate copolymerized polyester. 7. The fiber according to any one of claims 1 to 6, wherein the two polymers are a nylon 6 polymer and a copolymerized polyester polymer, and the nylon 6 polymer is a 3D crimped fiber disposed on the inside. 8. The fiber according to claim 7, wherein the fiber contains fibers that undergo a repeated phenomenon in which, in a hot water bath at a temperature of 80°C or higher, the nylon 6 polymer on the inside of the 3D crimped coil self-extends, thereby changing from a 3D crimped structure to a linear fiber form, and then, upon removal from the hot water bath, the yarn temperature is lowered and the absorbed water is dried, thereby returning to the 3D crimped state, and wherein the elongation change rate (Equation 1) after 30 minutes of boiling water treatment is 130 to 200%. Elongation change rate: (length after hot water treatment - length when dry) / length when dry x 100 (%) Formula 1 (However, all length measurements are length under a light load of skein fineness (dtex) x 2 mg / dtex) 9. A modified side-by-side composite cross section fiber according to claim 7 or 8, wherein the nylon 6 polymer inside the three-dimensionally crimped coil self-extends in a hot water bath at a temperature of 80°C or higher, causing the bonded surfaces to peel off when the nylon 6 polymer changes from a three-dimensionally crimped structure to a linear fiber form.10. The modified side-by-side composite cross section fiber according to claim 7 or 8, wherein, in a hot water bath at a temperature of 80°C or higher, the nylon 6 polymer on the inside of the three-dimensionally crimped coil reverses to the configuration on the outside of the three-dimensionally crimped coil due to self-extension, resulting in peeling of the bonded surfaces. 11. A method for producing a modified cross section fiber, comprising peeling off the bonded surfaces of the modified side-by-side composite cross section fiber according to claim 1. 12. A method for producing a modified cross section fiber according to claim 11, wherein the peeling method is a hot water shrinkage treatment. 13. A method for producing a fabric, comprising forming a sheet using the modified side-by-side composite cross section fiber according to claim 1, which consists of two polymers with different glass transition points and wherein the cross-sectional shapes of the polymer components are modified, and peeling off the modified side-by-side composite cross section fiber. 14. A method for producing a fabric according to claim 13, wherein the two polymers with different glass transition points are polyester and polyamide. 15. A method for producing a fabric according to claim 13 or 14, wherein the modified cross sections of each polymer are the same cross-sectional shape. 16. 16. The method for producing a fabric according to any one of items 13 to 15, wherein the single fiber fineness of each component after peeling is 2.0 dtex or less. 17. The fabric has a basis weight of 30 to 300 g / m. ２ 17. A method for producing a fabric according to any one of claims 13 to 16, wherein the fabric is a knitted fabric and has a density of 50 to 120 courses / 2.54 cm and 40 to 100 wales / 2.54 cm. 18. A method for producing a fabric according to any one of claims 13 to 17, wherein the fabric is a knitted fabric and has a density of 50 to 120 courses / 2.54 cm and 40 to 100 wales / 2.54 cm. 19. A method for producing a fabric according to any one of claims 13 to 17, wherein the fabric is a woven fabric and has a warp density of 50 to 300 threads / 2.54 cm and a weft density of 50 to 300 threads / 2.54 cm. 20. A method for producing a fabric according to any one of claims 13 to 19, wherein the fabric has an abrasion resistance of 30,000 cycles or more according to the Martindale method of JIS-L1096.

[0010] According to the present invention, there are provided an irregular side-by-side composite cross section fiber that can be easily split in a post-spinning process and becomes an irregular cross section fiber with excellent texture, and a method for producing an irregular cross section fiber and fabric using the same.

[0011] 1. Atypical side-by-side composite cross section fiber of the present invention, which is X-shaped and has two protrusions on each polymer. 2. Atypical side-by-side composite cross section fiber of the present invention, in which each polymer is C-shaped and has two protrusions on each polymer. 3. Atypical side-by-side composite cross section fiber of the present invention, in which each polymer is rectangular and the short sides are joined. 4. Round side-by-side cross section fiber formed by bonding semicircles used in comparative examples. 5. Diamond-shaped side-by-side cross section fiber formed by bonding triangles used in comparative examples. 6. SEM photograph showing the crimp state after hot water treatment of the yarn made from the atypical side-by-side composite cross section fiber of Example 1. 7. SEM photograph showing the crimp state after hot water treatment of the yarn made from the round side-by-side cross section fiber of Comparative Example 1. 8. Knit structure diagram used in Examples 6, 11, and Comparative Example 4. 9. Knit structure diagram used in Examples 7 and 10. 10. Weave structure diagram used in Examples 8, 9, 12, 13, 14, and Comparative Example 5.

[0012] The present invention will be described in detail below. The modified side-by-side composite cross-section fiber of the present invention (hereinafter sometimes referred to as the "composite cross-section fiber" or "composite fiber" of the present invention) is a modified side-by-side composite cross-section fiber composed of two polymers with different glass transition temperatures, in which the cross-sectional shapes of the polymer components are modified. Furthermore, it is essential that the ratio X / Y, which is the inter-polymer distance X connecting the centers of the minimum encompassing circles of the modified cross-sections of each polymer component in the fiber cross-section, to the bonded surface distance Y in the cross-section, be 1.1 or greater. The minimum encompassing circle is the circle with the smallest area that encompasses the modified cross-section. In special cases, such as a regular polygon, this minimum encompassing circle will coincide with the circumscribing circle, but it will have a diameter equal to or smaller than the circumscribing circle. Although there are cross-sections for which a circumscribing circle cannot be set, it is possible to draw a minimum encompassing circle.

[0013] Furthermore, the fiber having an irregular cross section of the present invention is preferably a fiber having a protruding irregular cross section, and is preferably a side-by-side irregular composite cross section fiber in which protruding irregular cross sections of polymers with different glass transition temperatures are bonded side by side. Furthermore, the side-by-side irregular composite cross section fiber is preferably an irregular cross section fiber having two or more, particularly two to four, protruding cross sections. It is also preferably an irregular side-by-side composite cross section fiber with high crimpability.

[0014] In the present invention, the term "irregular shape" refers to a non-circular shape or a shape not similar to a circle, i.e., a cross section of a fiber formed from the polymer is not a circle or a shape obtained by simply dividing a circle, such as a semicircle.

[0015] In the present invention, by making each polymer component have a noncircular shape, preferably a noncircular shape having protrusions, it is possible to make the inter-polymer distance X connecting the centers of the smallest encompassing circles of the modified cross sections of each polymer component in the fiber cross section larger than in the case of a fiber with the same fineness and a circular cross section, and the moment acting on each component in the processing step increases, resulting in a composite cross-section fiber that is more easily crimped and split.

[0016] More specific examples of non-circular irregular cross-sectional shapes include fibers in which two V-shaped polymers are bonded side by side, resulting in an X-shaped cross section for the entire composite fiber, as shown in Figure 1. Alternatively, the cross section of one polymer fiber component may have three protrusions as shown in Figure 2, or two protrusions may have a curved shape as shown in Figure 3. Furthermore, for ease of processability, it is preferable that the two polymer components are symmetrical with respect to the bonding surface, particularly point symmetrical.

[0017] In such a composite cross-section fiber in which different types of polymers are bonded side by side, the force acting on each polymer component is proportional to the distance between the two polymer components. In the present invention, by forming a non-circular modified cross section having a protrusion or the like, it is possible to increase the distance between the two polymer components, and even if the fiber has a small fineness, the amount of moment acting on each component increases, resulting in the production of a modified side-by-side composite cross-section fiber that exhibits a large crimped coil.

[0018] The inter-polymer distance X defined in the present invention is the distance between the centers of the smallest inclusive circles of the protruding cross sections of each component, as shown in Figures 1 to 6. The bonded surface distance Y is the bonded distance length of the cross section that forms the boundary between the two polymers. In the case of a curve, the bonded surface distance Y is the length of the curve along the bonded surface. Incidentally, as the bonded surface distance Y increases, the overlap of the smallest inclusive circles of each component tends to increase, and the greater the degree of overlap of the smallest inclusive circles, the smaller the inter-polymer distance X of the present invention. For example, in Figure 5, the two polymer components are bonded at the diameter of the circle, so the bonded surface distance Y is the largest for smallest inclusive circles of the same diameter (which coincides with the circumscribing circle), and the smallest inclusive circles of both polymer components are the same, resulting in the inter-polymer distance X being 0 (zero).

[0019] Furthermore, the inter-polymer distance X connecting the centers of the smallest encompassing circle of this modified cross section significantly affects the coil diameter when the conjugate fiber assumes a crimped shape. In the case of a conjugate fiber with a fineness throughout, the value of the inter-polymer distance X is inevitably small. However, in the case of a fiber cross-sectional shape with a modified cross section, such as one having a protrusion shape, as in the present invention, it is possible to increase the inter-polymer distance X between the two components even with the same fineness, and in particular, in the case of a finer fiber, a conjugate fiber is obtained that is likely to exhibit a large crimped coil. Here, the value of the inter-polymer distance X is preferably 10 μm or less, and more preferably in the range of 1 to 8 μm.

[0020] The bonding surface distance Y defined in the present invention is the length of the bonding surface between two polymers with different glass transition points, and in the case of a curve, it is the length of the curve along the bonding surface. In the present invention, a smaller bonding distance is preferable in terms of increasing the crimp size and facilitating fiber splitting. However, if the bonding distance is too small, bonding of the two polymers after extrusion from the spinneret tends to be impossible, making it difficult to form the cross section of the composite fiber and to develop crimp. Conversely, if the bonding distance is too large, the crimp size of the composite fiber becomes small and the separation of the two components during textile processing becomes insufficient. The value of the bonding surface distance Y is preferably in the range of 3 to 13 μm, and particularly preferably in the range of 5 to 12 μm.

[0021] In the present invention, the value of X / Y, which is the ratio of the inter-polymer distance X to the bonded length Y, must be 1.1 or greater. This value means that the inter-polymer distance X of both components in the cross section is greater than the bonded length Y, and such an irregular side-by-side composite cross section fiber of the present invention is a fiber that has a large crimped coil diameter and exhibits high crimp development ability. When the crimped coil is large, a fabric made from this irregular side-by-side composite cross section fiber of the present invention will have a bulging texture, resulting in a soft fabric. Furthermore, such a fiber will undergo a large change in shape when the coil shape is changed, as described below, and can be made into a fabric with a varied texture.

[0022] Furthermore, the modified side-by-side composite cross-section fiber of the present invention has a high crimp development ability, allowing it to develop fiber crimps by resisting the restraining force of woven or knitted fabrics. As a result, fabrics such as woven or knitted fabrics using the fiber can also have a high-quality, delicate texture and appearance. This is because the shapes of the fibers vary widely, and as will be described later, in such composite cross-section fibers of the present invention, each component is likely to split into modified cross-section fibers, and the split modified cross-section fibers tend to be randomly mixed both inside and outside the fiber bundle. If the X / Y ratio is less than 1.1, only fabrics lacking in volume and a natural mixed feel can be obtained. This is because the crimped coil of the composite cross-section fiber tends to be small, and yarns and fabrics using this composite cross-section fiber lack bulkiness and the splittability of both components is poor.

[0023] However, in the atypical side-by-side composite cross section fiber of the present invention, the X / Y value is 1.1 or greater. Therefore, the crimp coil becomes larger, and when such a composite fiber is used, fabrics with a fine, delicate texture and appearance are obtained. Furthermore, this characteristic is particularly pronounced when a component that self-extends in warm water, such as nylon 6, is used as one of the polymers constituting the composite fiber. That is, the crimp morphology changes significantly, and the high extensibility makes the bonded surfaces more susceptible to peeling and splitting. Furthermore, split fibers with fine fineness and an atypical cross section are randomly present inside and outside the fiber bundle, enabling fabric expression with a rich volume and natural feel. The value of X / Y, which is the ratio of the inter-polymer distance X to the bonded distance Y, is preferably 1.2 or greater and 5 or less, and particularly preferably 1.3 or greater and 2.5 or less. However, if this value is too large, the degree of atypicality becomes too great, and it becomes necessary to lower the polymer temperature in order to reduce the Bella's effect or surface tension after extrusion from the spinneret, which tends to reduce the strength and elongation of the fiber.

[0024] More specifically, the modified cross sections of each component of the modified side-by-side composite cross section fiber of the present invention are preferably, for example, shapes such as those shown in Figures 1 to 4. Furthermore, it is preferable that each polymer component has a modified cross section with two or more protrusions, as shown in Figures 1 to 3. Alternatively, the protrusions of the polymer components may be curved.

[0025] More specifically, for example, the fiber in Figure 1 is a fiber in which, when viewed from the joining surface of the two polymers, the two left and right polymers each have two protrusions, forming a V-shape, and the overall cross section of the fiber joined side by side is an X-shape. Figure 2 shows three protrusions on each side when viewed from the joining surface, while Figure 3 shows two curved protrusions on each side when viewed from the joining surface. Note that Figure 4 shows a single protrusion shape, but the inter-polymer distance X is large relative to the length of the joining surface Y, resulting in a fiber that is prone to splitting in later processes. Conversely, in the case of a conjugated fiber in which each component is semicircular, as shown in Figure 5, the circumscribed circles of the left and right components coincide, eliminating the inter-polymer distance X connecting the centers of the circumscribed circles of the modified cross sections of each polymer component, and also increasing the joining surface, resulting in a fiber with less crimp and less prone to splitting in later processes.

[0026] In the atypical side-by-side composite cross section fiber of the present invention, by making the cross section of the fiber atypical shape in this way and optimizing the value of the ratio X / Y of the inter-polymer distance X to the bonding distance length Y, the fiber becomes one that is easily crimped and easily split by slight distortion or stress concentration, and fabrics made from the atypical fiber after splitting have an excellent texture.

[0027] Here, the two polymers with different glass transition temperatures constituting the irregular side-by-side composite cross section fiber of the present invention will be described in more detail. The two polymers used in the present invention are preferably polymers that, when spun, drawn, and then heat-treated, will become fibers with significantly different shrinkage rates. The two polymers may be polymers that separately constitute one side of the irregular side-by-side composite cross section fiber, and the polymers may be copolymer polymers, etc. Furthermore, the two polymers may be polymers with different degrees of polymerization, various component ratios, additives, etc., so long as they have different glass transition temperatures.

[0028] However, it is preferable that these two polymers are well bonded during spinning and can be stably melt-spun into a composite fiber, and for example, a combination of polyamide and polyester is preferable. More specifically, nylon 6 is particularly preferable as the polyamide, and a copolymer polyester containing a sulfonate group or the like is preferable as the polyester. Furthermore, polyethylene terephthalate or polytrimethylene terephthalate is preferable as the polyester.

[0029] The polymer with a lower glass transition temperature constituting such a composite fiber is preferably polyamide or the like, and its glass transition point preferably ranges from 45 to 55°C. The polymer with a higher glass transition temperature preferably has a glass transition point in the range of 70 to 90°C. The difference in glass transition temperature between the two polymers is preferably 50°C or less, and more preferably in the range of 10 to 40°C. A temperature difference greater than this tends to increase practical disadvantages, such as poor thinning followability of the two components during the spinning process, resulting in poor spinning, or reduced fiber strength and elongation due to significant orientation suppression of the component with a lower glass transition temperature. Conversely, if the temperature difference in glass transition temperature is too small, the difference in physical properties is small, the crimp percentage of the composite fiber is reduced, and the atypical fibers derived from each polymer tend to be less likely to peel from the composite fiber.

[0030] The intrinsic viscosity η of the polymer on the low glass transition point side is preferably in the range of 1.0 to 1.6 when measured in an m-cresol solution at 30° C. The intrinsic viscosity η of the polymer on the high glass transition point side is preferably in the range of 0.4 to 0.7 when measured in an m-cresol solution at 30° C.

[0031] As a preferred example of a polymer having a high glass transition temperature used in such a composite fiber, the copolymer polyester is mentioned above. The polyester as the main component is preferably polyethylene terephthalate or polytrimethylene terephthalate.

[0032] In particular, the copolymerized polyester is preferably a modified polyester containing a sulfonate group. A preferred method for modifying the polyester by incorporating a sulfonate group is to copolymerize a compound having an alkali or alkaline earth metal salt or a phosphonium salt of sulfonic acid and one or more functional groups capable of forming an ester.

[0033] More specifically, examples of copolymerization components used for such polymers having a high glass transition temperature include 5-sulfoisophthalic acid and its ester derivatives, 5-sulfonium sulfoisophthalic acid and its ester derivatives, sodium p-hydroxyethoxybenzenesulfonate, etc. Among these, 5-sulfoisophthalic acid is preferably used.

[0034] The copolymerization amount of such copolymerization components is preferably 0.5 to 7 mol %, more preferably 1.5 to 4 mol %. If the amount is too small, the adhesion to polymers with low glass transition temperatures such as nylon-6 will be insufficient, which is undesirable as peeling may occur during the spinning process. On the other hand, if the amount is too large, the melt viscosity of the copolymer increases, which may result in reduced spinnability and other process stability problems.

[0035] Furthermore, the polyester preferably used in the present invention may contain other copolymerization components such as dioxy compounds such as diethylene glycol and hexamethylene glycol, and aliphatic dicarboxylic acids such as adipic acid, isophthalic acid and phthalic acid. The glass transition temperature of such high-glass-transition-point polymers can be adjusted by the mole percentage of copolymerization components such as sodium sulfoisophthalate.

[0036] Titanium oxide, colorants, light stabilizers, etc. may also be added as additives to the polymers such as polyester and polyamide used in the present invention, as long as they do not cause problems in spinning, drawing, and textile processing. From the viewpoint of crimp development, the ratio of the two polymer components in such a modified side-by-side composite cross section fiber of the present invention is preferably around 50:50, and it is preferable to vary the ratio of the two components within the range of 40:60 to 60:40.

[0037] The modified side-by-side composite cross section fiber of the present invention is preferably a three-dimensionally crimped modified side-by-side composite cross section fiber having the modified cross section polymer arrangement as described above and using polymers with different glass transition points, with the polymer with the lower glass transition point being positioned on the inner side of the crimp.

[0038] For the composite cross-section fiber of the present invention to form such a crimped coil, it is preferable that the difference in glass transition temperatures between the two polymers constituting the side-by-side components be large, which enables the production of a larger crimped coil. This is because, during the spinning process, after the polymers are discharged from the nozzle and pass through the heat-retention zone, cooling air is used to cool the spun yarn while promoting orientation and crystallization. During this process, the extensional viscosity of the polymer with a higher glass transition point increases first, thereby promoting orientation and crystallization relative to the other polymer. Meanwhile, the other polymer with a lower glass transition point is not sufficiently increased in extensional viscosity, but its deformation is promoted to follow the spinning line speed of the polymer with a higher glass transition point, suppressing orientation and crystallization. In this way, the difference in crystal orientation between the two components increases, thereby increasing the difference in shrinkage force between the two components and enhancing crimping performance. In this case, the polymer with a lower glass transition point becomes a less oriented polymer component, resulting in less orientation and a larger shrinkage rate, and is therefore positioned on the inner side of the crimped coil.

[0039] As mentioned above, the temperature difference between the glass transition points of the two polymer components used in the present invention is preferably 50°C or less. It is more preferably in the range of 10 to 40°C. A larger temperature difference can lead to poor spinning performance due to poor thinning followability of both components during the spinning process, or the orientation of the component with a lower glass transition temperature is significantly inhibited, resulting in low strength and elongation. Thus, as mentioned above, the modified side-by-side composite cross section fiber of the present invention is preferably crimped. Here, the crimped fiber is preferably three-dimensionally crimped or false-twisted, and three-dimensionally crimped fiber is particularly preferred.

[0040] Furthermore, by making a fabric using the modified side-by-side composite cross section fiber of the present invention and subjecting it to heat treatments such as scouring and dyeing, it is preferable that the composite cross section fiber in the final fabric have the following two forms: (1) A composite fiber that changes from a crimped structure to a flat, linear fiber form, and then returns to its original crimped state as it is removed from a hot water bath, the yarn temperature drops, and the absorbed water is naturally dried. (2) Two types of modified cross section fibers whose bonding surfaces are peeled off.

[0041] The modified cross-section fibers composed of each single component of (2) are mainly generated in the following steps (2-1) and (2-2). In particular, when a polymer that is prone to self-extension by water, such as nylon 6, is used, it is preferable to obtain modified cross-section fibers with peeled bonding surfaces in step (2-2). (2-1) When the composite cross-section fiber changes from a crimped structure to a flat, linear fiber form, the bonded surfaces peel off, resulting in two types of modified cross-section fibers. (2-2) The fiber components, such as nylon 6 polymer, on the inside of the coil are reversed to the configuration on the outside of the coil due to self-extension, resulting in two types of modified cross-section fibers with peeled bonding surfaces.

[0042] To achieve the above-mentioned state, it is particularly preferable that the modified side-by-side composite cross section fiber of the present invention uses nylon 6 polymer as the polymer with a low glass transition temperature and a copolymer polyester polymer as the polymer with a high glass transition temperature, thereby forming a three-dimensionally crimped fiber in which the nylon 6 polymer is positioned on the inside. When using nylon 6 polymer and a copolymer polyester polymer in this way, the modified side-by-side composite cross section fiber of the present invention, including the above (1) and (2), is preferably a fiber as described below.

[0043] That is, the modified side-by-side composite cross section fiber of the present invention, which satisfies (1) above, includes a fiber that undergoes a repeated phenomenon in which, in a hot water bath at a temperature of 80°C or higher, the nylon 6 polymer inside the 3D crimped coil self-extends, thereby changing from a 3D crimped structure to a linear fiber form, and then, upon removal from the hot water bath, the yarn temperature drops and the absorbed water is dried, returning to the 3D crimped state, and is preferably a modified side-by-side composite cross section fiber whose elongation change rate (Equation 1) after 30 minutes of boiling water treatment is 130 to 200%. Equation 1: Elongation change rate: (length after hot water treatment - length when dry) / length when dry x 100 (%) (Note that the length measurements are all length under a light load of hank fineness (dtex) x 2 mg / dtex).

[0044] Here, the modified side-by-side composite cross section fibers of the present invention do not necessarily have to be all fibers that repeatedly and reversibly change between crimped fibers and straight fibers as described above (1); it is also preferable that the fibers include modified cross section fibers in which the bonding surfaces are peeled off as described above (2).

[0045] When such reversibly changing atypical side-by-side composite cross section fibers are included, nylon 6 is initially arranged inside the coil of the atypical side-by-side composite cross section fibers due to its low orientation, but in a subsequent process, its self-extending property in hot water causes a phenomenon in which the crimp state of the composite cross section fibers changes. As a result, when the atypical side-by-side composite cross section fibers of the present invention are immersed in hot water or dried during textile processing using the atypical side-by-side composite cross section fibers, the apparent fiber length changes due to a change in the coil structure, and even though the fibers are in a state where they are constrained to each other in the woven or knitted fabric structure, the fibers expand and contract and the crimped coil structure changes, resulting in a mixing effect in which single yarns are rearranged within the fiber bundle, and as a result, yarns and fabrics using the composite fibers of the present invention can express a variety of natural fiber forms like natural fibers.

[0046] Furthermore, at this time, the crimped form of nylon 6 is stretched by its self-elongation in hot water, and the elongation change rate, which is the length under light load, is preferably 130 to 200%. Subsequently, upon drying, the crimped state is restored, and the apparent length shortens and returns to its original state. Since the return speed differs between each single yarn, various single yarn arrangements can be adopted, resulting in the development of a mixing effect. If the self-elongation rate is low, it tends to be difficult to achieve splitting or a mixing effect. Furthermore, if the self-elongation rate is too high, the fiber structure of nylon 6 is underdeveloped, preventing repeatability of elongation / contraction, and the effect is limited. A more preferable elongation change rate is in the range of 140 to 180%.

[0047] The modified side-by-side composite cross section fiber of the present invention, which satisfies (2) above, is also preferably a fiber that has been obtained by undergoing the process (2-1) described above. That is, the modified side-by-side composite cross section fiber of the present invention is preferably a modified side-by-side composite cross section fiber in which the bonded surfaces peel off when the nylon 6 polymer inside the three-dimensionally crimped coil self-extends in a hot water bath at a temperature of 80°C or higher, changing from a three-dimensionally crimped structure to a linear fiber form. The split fibers exhibit various properties, such as softness, gloss, and an ultra-fine feel, due to the fineness and modified cross section effect.

[0048] Furthermore, as another example of the above (2), the modified side-by-side composite cross section fiber of the present invention is preferably a fiber obtained by undergoing the above step (2-2) or the like to become the following: That is, the modified side-by-side composite cross section fiber of the present invention is preferably a modified side-by-side composite cross section fiber in which, in a hot water bath at a temperature of 80°C or higher, the nylon 6 polymer on the inside of the three-dimensionally crimped coil reverses to the configuration on the outside of the three-dimensionally crimped coil due to self-extension, and the bonded surfaces peel off.

[0049] When this phenomenon is utilized to dye the bonded polymer components with different dyes, the fibers are mixed randomly due to the movement of the split single yarns within the fiber bundle, and instead of an artificial mix of different colors, a delicate mix of different colors is created, which changes color depending on the viewing angle and creates deep shadows, making it possible to produce high-quality fabrics.

[0050] As for the physical properties of the modified side-by-side composite cross section fiber of the present invention, its thermal stress is preferably in the range of 0.15 cN / dtex to 0.5 cN / dtex. It is more preferably 0.2 cN / dtex to 0.4 cN / dtex. The thermal stress indicates the crimp development during subsequent textile processing. If the thermal stress is too low, a large crimp structure will not develop, the fabric will have little expansion, and it will be difficult to achieve a good mix effect, such as the random distribution of split fine fibers inside and outside the fiber bundle. On the other hand, if the thermal stress is too high, the fibers themselves will become hard due to shrinkage, or the fabric density will increase, making it difficult to achieve the fluffy, soft texture desired by the present invention.

[0051] The crimp percentage of the modified side-by-side composite cross section fiber is preferably 4% or more, more preferably 4.5% to 20%, and particularly preferably 10 to 18%. If the crimp percentage is too low, the difference in physical properties between the bonded cross-sectional components will be small, the coiling force due to crimping will be small, and it will be difficult to obtain good texture such as fluffiness and softness.

[0052] Furthermore, the single fiber fineness of the modified side-by-side composite cross section fiber of the present invention is preferably in the range of 0.2 dtex to 5 dtex. It is even more preferably in the range of 0.5 to 4 dtex. If the single fiber fineness is too small, it will be difficult to peel the fibers to form two types of modified cross section fibers, or the fiber strength and elongation will be too low, making it difficult to handle, and other process difficulties will arise. Furthermore, if the single fiber fineness is too large, it will be difficult to achieve a soft, delicate texture.

[0053] The fineness of the components that become the modified cross-section fibers after the modified side-by-side fibers are peeled or split is preferably 2 dtex or less for both components, more preferably 1.6 dtex or less and 0.1 dtex or more, and particularly preferably a fine fiber of less than 1.2 dtex and 0.5 dtex or more. When the modified cross-section fiber component in the composite cross-section fiber has such a low fineness, cross-section yarns of finer fineness are randomly mixed in a fabric using the modified side-by-side composite cross-section fiber of the present invention, and softness and excellent changes in appearance are obtained.

[0054] The strength and elongation of the modified side-by-side composite cross section fiber of the present invention are preferably 1.8 cN / dtex or more in strength and 20% or more in elongation. It is particularly preferable that the strength be in the range of 2 to 4 cN / dtex and the elongation be in the range of 25 to 40%. If both the strength and elongation are too low, problems will arise in terms of textile quality due to single yarn breakage and friction in subsequent weaving / knitting and processing steps.

[0055] The irregular side-by-side composite cross section fiber of the present invention can be obtained, for example, by the following manufacturing method for an irregular side-by-side composite cross section fiber. That is, this manufacturing method for an irregular side-by-side composite cross section fiber comprises discharging two polymers having different glass transition points from respective irregular cross section holes, bonding the two components inside and / or outside the nozzle hole to form a side-by-side cross section, and then spinning, drawing, and heat setting. The irregular side-by-side composite cross section fiber obtained by this manufacturing method is an irregular side-by-side composite cross section fiber made of two polymers having different glass transition points, in which the cross-sectional shapes of the polymer components are irregular, and in which the ratio X / Y, which is the inter-polymer distance X connecting the centers of the circumscribed circles of the irregular cross sections of each polymer component, to the bonded surface distance Y in the cross section, is 1.1 or more.

[0056] Furthermore, it is preferable to form a cross-sectional fiber in which protruding irregular cross sections of polymers with different glass transition points are bonded side by side. More specifically, the manufacturing method is as follows: for example, two polymers are melted in separate extruders and introduced into a spinning pack equipped with a spinneret using a metering pump such as a gear pump. The polymers are distributed to several holes in the spinneret and discharged from separate irregular discharge holes. The two components are then bonded together to form a side-by-side composite cross section with irregular cross sections, which is then wound up at various speeds to form an undrawn yarn.

[0057] After winding the undrawn yarn, it is also possible to draw it in a separate drawing machine. Alternatively, a direct draw spinning process is also possible in which the undrawn yarn is preheated on a take-up roller without being wound, and then drawn and heat-set between heat-setting rollers before being wound. Furthermore, it is also preferable to produce a partially oriented yarn (POY) with a residual elongation in the range of 100 to 150% at a high spinning speed, and then produce a false twist textured yarn (DTY textured yarn) in a false twisting process, or to mix the yarn with other yarns to produce a composite fiber. The spinning speed in these cases is preferably in the range of 1000 m / min to 3500 m / min.

[0058] Furthermore, in the stretching step, it is preferable to stretch the film using high-temperature rollers that are 10 to 30°C higher than the higher glass transition temperature of the polymer, and to heat-set the film by winding the film around high-temperature rollers that are 20 to 50°C higher than the crystallization temperature or by passing the film through a non-contact heater, thereby preheating and heat-setting the film. In order to adjust the shrinkage rate during subsequent textile processing, it is also a preferable step to provide a cooling roller after the heat-setting rollers and perform a relaxation heat treatment to reduce the shrinkage rate.

[0059] The modified side-by-side composite cross section fiber of the present invention thus obtained is converted into another method for producing a modified cross section fiber of the present invention by peeling the bonded surfaces of the modified side-by-side composite cross section fiber. In the method for producing such another modified cross section fiber of the present invention, the peeling method is preferably a hot water treatment. The hot water shrinkage treatment is preferably performed with hot water at a temperature of 80°C or higher. Boiling water treatment at 90 to 100°C is more preferred. The treatment time is preferably 1 to 10 minutes, particularly 2 to 5 minutes. It is preferable that no dissociation has occurred at the bonded surfaces before the hot water shrinkage treatment, and that separation has occurred at the bonded surfaces after the hot water shrinkage treatment, resulting in separation into two types of fibers composed of the respective polymer components alone.

[0060] After the hot water treatment, it is preferable to dry the fibers to return them to their original length. This improves the subsequent processability of the fibers. It is also preferable to repeat the hot water treatment and drying treatment multiple times to ensure more complete separation of the bonded surfaces. It is also preferable to repeat the process two to five times. In this method for producing modified cross-section fibers in which the bonded surfaces of modified side-by-side composite cross-section fibers are peeled off, the degree of splitting (e.g., peeling of the bonded surfaces) can be adjusted in each of the subsequent processing steps, such as weaving / knitting, scouring, presetting, dyeing, and final setting.

[0061] By using such a modified side-by-side composite cross section fiber of the present invention, another method for producing a fabric having a good texture and a natural mixed effect appearance can be achieved, which is another method for producing a fabric, comprising forming a sheet using the modified side-by-side composite cross section fiber of the present invention and peeling off the modified side-by-side composite cross section fiber.

[0062] The modified side-by-side composite cross section fiber used in the fabric is the modified side-by-side composite cross section fiber of the present invention described above, and it is particularly preferred that the two polymers having different glass transition temperatures are polyester and polyamide (also called "nylon"). It is also preferred that each modified cross section fiber component made of two polymers have the same cross-sectional shape.

[0063] By adopting such a manufacturing method, it is possible to obtain a fabric containing, for example, polyester modified cross-section fiber and polyamide modified cross-section fiber, characterized in that the polyester modified cross-section fiber and the polyamide modified cross-section fiber have the same surface shape.

[0064] In the fabric of the present invention, irregular cross-section fibers made of different polymers are randomly mixed within the fiber bundle, resulting in a deep color, a fine chambray effect, a bulky spun texture, and abrasion resistance.

[0065] Here, the monofilament fineness ratio (A:B) between the two types of modified cross-section fiber (A) and modified cross-section fiber (B) made of different polymers is preferably in the range of 40:60 to 60:40. Furthermore, if the cross-sectional shape of the modified cross-section fiber has two or more (more preferably 2 to 4) protrusions, bulkiness and a spun-like texture can be obtained, which is preferable. Specific examples of such shapes include a V-shape, a three-protrusion type, and a C-shape.

[0066] The single fiber fineness of the two types of modified cross-section fibers (A) and (B) is preferably 2.0 dtex or less. It is more preferably 1.6 dtex or less, particularly preferably in the range of 0.1 to 1.5 dtex or 0.5 to 1.2 dtex. The finer modified cross-section fibers are randomly mixed at the single fiber level to obtain a higher level of softness and an excellent chambray-like appearance. It is also preferable that these modified cross-section fibers are crimped fibers. Furthermore, it is preferable that the two types of modified cross-section fibers (A) and (B) are formed by splitting side-by-side composite fibers.

[0067] The modified side-by-side composite cross section fiber used in the fabric is the modified side-by-side composite cross section fiber of the present invention described above, and the two types of modified cross section fibers (A) and (B) that ultimately constitute the fabric are preferably modified cross section fibers obtained by the method for producing a modified cross section fiber using the modified side-by-side composite cross section fiber of the present invention described above.

[0068] The cross-sectional shape of the modified side-by-side composite cross-section fiber is preferably one of those shown in Figures 1 to 4 described above. The distance X between the centers of the two components is proportional to the coil diameter of the resulting crimped shape. The inventors discovered that by using a modified cross-section with a protruding shape, the distance between the centers of the two components can be increased, and a large crimped coil can be produced even with a finer fiber. Furthermore, because the modified side-by-side composite cross-section fiber is a crimped fiber, the resulting fabric has excellent texture.

[0069] In particular, by setting the ratio of the distance X between the centers of both components to the joining length Y of both cross sections to 1.1 or more, the shape of the fiber changes significantly when the swelling or coil shape of the fabric changes, allowing for a varied fabric texture. Furthermore, a high crimp development potential allows for fiber crimp to develop in response to the restraining force of the woven or knitted fabric, which also results in a wide variety of fiber shapes, and the split fibers are mixed randomly inside and outside the fiber bundle, resulting in a high-quality, delicate texture and appearance. Preferably, the ratio is 1.2 or more and 2.5 or less. If the ratio is too large, it becomes necessary to lower the polymer temperature in order to reduce the Behruss effect or surface tension after extrusion from the spinneret in order to increase the degree of irregularity, which can result in practical problems such as reduced fiber strength and elongation.

[0070] In the present invention, the fibers preferably used are atypical side-by-side conjugate cross section fibers in which the polymers have different glass transition temperatures and the polymer with the lower glass transition temperature is positioned on the inner side of the crimp. The different polymers used in the conjugate fibers are preferably nylon 6 and a sulfoisophthalic acid cation salt copolymer polyester (more preferably a sodium sulfoisophthalate copolymer polyester), and the atypical side-by-side conjugate fibers in which nylon 6 is positioned on the inner side after crimping are particularly preferred.

[0071] Nylon 6 has a lower glass transition point than the copolyester, and is therefore positioned on the inner side of the crimp. The glass transition point of nylon 6 is approximately 50°C, preferably in the range of 45 to 55°C. When the copolyester is primarily composed of polyethylene terephthalate or polytrimethylene terephthalate, the glass transition temperature is generally 70 to 90°C, depending on the copolymerization mole percentage of sodium sulfoisophthalate, and the result is an atypical side-by-side composite cross section fiber in which nylon 6 is positioned on the inner side of the crimp.

[0072] The nylon 6 placed on the inside is in a low orientation state, and therefore has a large self-extension rate in hot water, which causes changes in crimp and causes it to try to elongate beyond the length of the polyester component, making it prone to interfacial peeling.

[0073] Here, the sulfoisophthalic acid cation salt copolymerized polyester is a modified polyester copolymerized with a compound having an alkali or alkaline earth metal salt of sulfonic acid, a phosphonium salt, or the like, and having one or more functional groups capable of forming an ester. The intrinsic viscosity η of this modified polyester (measured in an o-chlorophenol solution at 25°C) is preferably 0.4 to 0.7.

[0074] Suitable copolymerization components include 5-sodium sulfoisophthalic acid and its ester derivatives, 5-phosphonium sulfoisophthalic acid and its ester derivatives, sodium p-hydroxyethoxybenzenesulfonate, etc. Among these, 5-sodium sulfoisophthalic acid is preferably used, and the copolymerization amount is preferably 0.5 to 7 mol %, more preferably 1.5 to 4 mol %, based on the acid component of the copolymerized polyester.

[0075] The sulfonate groups in the polyester copolymerized with sulfoisophthalic acid and the amide groups in the polyamide polymer provide excellent electrostatic adhesion and result in fibers with excellent cross-sectional formability. If the copolymerization amount is too low, adhesion to nylon 6 tends to be insufficient, which can lead to peeling during the spinning process and a low glass transition temperature. On the other hand, if the copolymerization amount is too high, the melt viscosity of the polymer tends to increase, which can lead to reduced spinnability and other process stability issues.

[0076] Furthermore, other copolymerization components such as dioxy compounds, such as diethylene glycol and hexamethylene glycol, and aliphatic dicarboxylic acids, such as adipic acid, isophthalic acid and phthalic acid, may be copolymerized.

[0077] For nylon 6, the intrinsic viscosity η (measured in an m-cresol solution at 30°C) is preferably 1.0 to 1.6. Furthermore, such a combination of nylon 6 and sodium sulfoisophthalate copolymerized polyester is effective in producing a delicate fabric appearance by utilizing the heterochromaticity, particularly in the subsequent dyeing step, by using an acid dye or cationic dye suited to each dye.

[0078] The composite fiber preferably contains fibers that undergo a repeating process in which, during the textile processing step, nylon 6 or the like on the inside of the coil self-extends in a hot water bath at a temperature of 80°C or higher, thereby changing from a crimped structure to a flat, linear fiber form, and then returning to its original crimped state upon removal from the hot water bath, a decrease in the yarn temperature, and drying of the absorbed water. This is a phenomenon in which the crimped state of the fiber changes when nylon 6 or the like, which has low orientation, is positioned on the inside of the coil and utilizes its self-extension property in hot water. As a result, during textile processing, the apparent fiber length changes due to changes in the coil structure caused by immersion in hot water or drying. Therefore, even though the fibers are in a state where they are constrained to each other in the woven or knitted fabric structure, the fibers' elongation and crimped coil structure change, resulting in a mixing effect, such as the rearrangement of single fibers within the fiber bundle, which allows for variations in natural fiber forms similar to those of natural fibers.

[0079] The fabric of the present invention is obtained from modified side-by-side composite cross section fibers made of two polymers with different glass transition points. In addition to being composed solely of such fibers, the fabric may also contain other fibers (for example, ordinary round cross section fibers or modified cross section fibers with different cross-sectional shapes).

[0080] The weave of the fabric of the present invention is not particularly limited, and may be either a knitted fabric or a woven fabric. Suitable examples include knitted fabrics with knitting structures such as plain weave, twill weave, and satin weave, but are not limited to these. The number of layers may be a single layer or two or more layers.

[0081] In this case, if the fabric is a knitted fabric, the knitting density is preferably 50 to 120 courses / 2.54 cm and 40 to 100 wales / 2.54 cm. If the fabric is a woven fabric, the woven fabric density is preferably 50 to 300 warp threads / 2.54 cm and 50 to 300 weft threads / 2.54 cm. In the fabric of the present invention, the basis weight of the fabric is 30 to 300 g / m. ２ It is preferable that the range is within the range of

[0082] The fabric of the present invention can be obtained, for example, by knitting or weaving the composite fiber (and other fibers as needed) in a conventional manner, and then splitting the composite fiber into two types of modified cross-section fibers by heat treatment such as dyeing or water-repellent treatment.

[0083] When dyeing is performed, the temperature for the dyeing is preferably 100 to 140°C (more preferably 110 to 135°C), and the time for keeping the top temperature is preferably within a range of 5 to 40 minutes. The dyed fabric is preferably subjected to a final dry heat set. In this case, the temperature for the final dry heat set is preferably 120 to 200°C (more preferably 140 to 180°C), and the time is preferably within a range of 1 to 3 minutes.

[0084] Furthermore, various types of processing may be additionally applied, such as conventional raising processing, ultraviolet shielding, or processing to impart functions such as antibacterial agents, deodorizers, insect repellents, luminescent agents, retroreflective agents, negative ion generators, water absorption processing, water repellents, etc. By undergoing the heating step and drying step, the fabric of the present invention has a greater degree of fiber splitting and becomes a fabric with excellent texture.

[0085] The fabric thus obtained has the above-mentioned structure, and therefore has a deep color, a fine chambray effect, a bulky spun texture, and excellent abrasion resistance. The abrasion resistance of the fabric is preferably 30,000 times or more according to the Martindale method of JIS-L1096. It is more preferably in the range of 35,000 to 100,000 times.

[0086] The present invention also provides a textile product selected from the group consisting of clothing, linings, interlinings, socks, belly warmers, hats, gloves, sleepwear, bedding coverings, bedding covers, and car seat covering materials, which uses the above-mentioned fabric. Because such textile products use the above-mentioned fabric, they exhibit deep colors, a fine chambray effect, a bulky spun-like texture, and excellent abrasion resistance.

[0087] The side-by-side composite cross-section fiber of the present invention does not undergo cross-section peeling during the spinning stage, and by bonding the composite cross-sections together, the center-to-center distance between the two cross-sections is increased, resulting in a large crimp coil. Fabrication of this composite cross-section fiber, followed by post-processing with splitting, allows for the random mixing of ultrafine composite cross-section yarns made of different polymers within the fiber bundle, resulting in a fabric with a fluffy, good texture and a natural, mixed-effect appearance.

[0088] The present invention will be described in detail below. However, the present invention is not limited to the examples described below. The measurement methods used in the examples and comparative examples will be described below.

[0089] (1) Tensile strength and elongation Measurements are made according to JIS L 1013 under the conditions of a sample yarn length of 20 cm and a constant pulling speed of 20 cm / min. The maximum load on the load-elongation curve is divided by the fineness to obtain the breaking tensile strength (or tensile strength) (cN / dtex), and the elongation at this point is the breaking elongation (%).

[0090] (2) Crimp Rate A 30 cm long reel was made, and a heavy load of 220 mg / dtex and a light load of 20 mg / dtex were applied to the reel. ０ , L １Then, the sample is treated with boiling water for 30 minutes under a light load to induce crimping, and the moisture is removed using filter paper, followed by drying for 3 hours. Then, the length L is measured again under a heavy load. ３ After measuring, remove the heavy load and measure the length L ２ was measured. ０ , L ２ , L ３ The crimp rate was measured using the following formula: Crimp rate (TC) (%) = (L ２ -L ３ ) / L ０ ×100 (%)

[0091] (3) Elongation Change Rate A 30 cm long skein was made, and after treating it in boiling water for 30 minutes, it was taken out of the water, and the moisture was absorbed with filter paper. ４ After that, the load is removed and the specimen is dried for 3 hours. Then, the length L is measured under a light load. ５ Measure the length L ４ , L ５ Using the values ​​of , the elongation rate was measured according to the following formula: Elongation rate in boiling water = (L ４ -L ５ ) / L ４ ×100 (%)

[0092] (4) Glass transition temperature (Tg) About 10 mg of the pellet was sealed in an aluminum pan for measurement, and the glass transition temperature was measured using a differential scanning calorimeter manufactured by TA-instrument Co., Ltd. under conditions of a nitrogen gas flow atmosphere and a temperature rise rate of 10° C. / min.

[0093] (5) Inter-polymer distance X and bonded surface distance Y As shown schematically in Figures 1 to 6, the length of both components bonded side by side in the fiber cross section was defined as the bonded surface distance Y, and the length connecting the centers of the smallest encompassing circles of both components in the irregular cross section was defined as the inter-polymer distance X, and the ratio X / Y was calculated.

[0094] (6) Degree of Splitting A 36G cylindrical knit was made using a raw yarn composed of atypical side-by-side composite cross section fibers, and the yarn was scoured at 80° C., then dyed with an acid dye and then with a cationic dye at 100° C. The cylindrical knit was cut perpendicular to the fiber length direction, and the cross section was observed under an electron microscope. The degree of splitting from the atypical side-by-side composite cross section fibers to the atypical cross section fibers was judged as Grade 1 when it was less than 50%, Grade 3 when it was 50-80%, and Grade 5 when it was 80% or more.

[0095] (7) Random Mixing Property The surface of the tubular knit used in (6) above was observed, and two types of polymer components were dyed separately using an acid dye and a cationic dye of different colors. The tubular knit surface was judged as grade 5 if two-colored single yarns could be uniformly confirmed in the observed area, grade 3 if there were patchy two-colored areas / one-colored areas, and grade 1 if there were only one-colored areas.

[0096] (8) Fabric Weight: Measured according to JIS L1018-1998 6.4.

[0097] (9) Cover Factor of Fabric The warp cover factor (warp CF) and the weft cover factor (weft CF) were calculated using the following formula and added together: Warp CF = (DWp / 1.1) １／２ ×MWp Latitude CF=(DWf / 1.1) １／２ × MWf [DWp is the total warp fineness (dtex), MWp is the warp weave density (counts / 2.54 cm), DWf is the total weft fineness (dtex), and MWf is the weft weave density (counts / 2.54 cm)]

[0098] (10) Abrasion Resistance of Fabric An abrasion test according to JIS 1096 Martindale method was carried out.

[0099] (11) Fine chambray appearance of fabric A tester visually inspected the fabric and judged it as "good" if it had a fine chambray appearance at the single fiber level, and "bad" if it did not.

[0100] Example 1 Nylon 6 (low glass transition point) and 2.6 mol % 5-sodium isophthalic acid copolymerized polyethylene terephthalate (η = 0.55, high glass transition point) were spun at a spinning temperature of 265°C and a spinning speed of 2500 m / min, and wound up to obtain an X-shaped composite cross section fiber as shown in Figure 1, in which each component had two protrusions. This fiber was preheated and drawn at 90°C, heat-set in a slit heater at 180°C, and wound up at a winding speed of 600 m / min to obtain an irregular side-by-side composite cross section fiber. The cross section, fiber properties, and splittability of the obtained fiber were evaluated and the results are shown in Tables 1 and 2.

[0101] (Examples 2 to 5) Fibers with modified side-by-side composite cross sections were obtained in the same manner as in Example 1, except that the cross-sectional shape was changed. Example 2 has the cross-sectional shape of FIG. 2, in which cross sections with three projections are bonded together. Example 3 has the C-shaped cross-sectional shape of FIG. 3, in which two projections are formed. Example 4 has the cross-sectional shape of FIG. 4, in which rectangular cross sections are bonded together. Example 5 has the X-shaped cross section of FIG. 1, in which two projections are formed, and has a finer fineness than Example 1. The evaluation results of the cross-sections, fiber properties, splittability, etc. of the obtained fibers are shown in Tables 1 and 2.

[0102] (Comparative Examples 1 and 2) Side-by-side composite cross-section fibers were obtained in the same manner as in Example 1, except that the cross-sectional shape was changed. Comparative Example 1 is a circular side-by-side cross-section yarn formed by bonding together semicircles as shown in Figure 5, and Comparative Example 2 is a diamond-shaped side-by-side cross-section formed by bonding together triangles as shown in Figure 6. Evaluation results for the cross-sections, fiber properties, and splittability of the obtained fibers are also shown in Tables 1 and 2.

[0103] Comparative Example 3 A modified side-by-side composite cross section fiber was obtained in the same manner as in Example 1, except that two polymers with different molecular weights of 2.6 mol % 5-sodium isophthalic acid copolymerized polyethylene terephthalate (η = 0.55) were used instead of the low glass transition point nylon 6. The evaluation results of the cross section, fiber properties, splittability, etc. of the obtained fiber are shown in Tables 1 and 2.

[0104]

[0105]

[0106] Example 6 Nylon 6 (low glass transition point) and 2.6 mol % 5-sodium sulfoisophthalic acid copolymerized polyethylene terephthalate (η=0.55, high glass transition point) were spun at a spinning temperature of 265°C and wound up at a spinning speed of 2500 m / min to obtain a side-by-side composite fiber (weight ratio of both components: 50:50) with an X-shaped cross section as shown in Figure 1. This was preheated and drawn at 90°C, heat-set using a 180°C slit heater, and wound up at a winding speed of 600 m / min to obtain a yarn consisting of a modified side-by-side composite cross section fiber with a total fineness of 55 dtex / 48 fibers (crimp rate: 5.7%).

[0107] Next, using a 36-gauge circular knitting machine, a circular knit fabric with a smooth structure as shown in Figure 9 was knitted using the composite fiber. The knit fabric was then dyed using a disperse dye at a temperature of 130°C for a 15-minute hold time. During the dyeing process, a hydrophilizing agent (polyethylene terephthalate-polyethylene glycol copolymer) was added to the knit fabric at a ratio of 2 milliliters per liter of the dye liquor by performing a co-dye treatment. The circular knit fabric was then subjected to a final dry heat set at 160°C for 1 minute.

[0108] The resulting knitted fabric was a random mix of modified cross-section fibers made of nylon 6, which had been split from the composite fiber, and modified cross-section fibers made of 2.6 mol% 5-sodium sulfoisophthalic acid copolymerized polyethylene terephthalate, forming a V-shaped cross-section (having two protrusions), and had a deep color, a fine chambray effect, a bulky spun-like texture, and abrasion resistance. The single fiber fineness of the polyester (sodium sulfoisophthalate copolymerized polyester) fiber and polyamide (nylon 6) fiber contained in the knitted fabric was both 0.6 dtex. The evaluation results are shown in Table 3.

[0109] Example 7 Nylon 6 (low glass transition temperature) and 2.6 mol% 5-sodium sulfoisophthalic acid copolymerized polyethylene terephthalate (η = 0.55, high glass transition temperature) were spun at a spinning temperature of 265°C and wound up at a spinning speed of 2500 m / min to obtain a partially oriented yarn (POY) of a side-by-side type (weight ratio of both components: 50:50) and X-shaped composite fiber (total fineness: 92 dtex / 48 fibers) as shown in Figure 1. The obtained partially oriented yarn was subjected to false twist crimping at a yarn speed of 500 m / min, a heater temperature of 155°C, and a draw ratio of 1.6 to obtain a false twist crimped yarn (DTY textured yarn) (total fineness: 55 dtex / 48 fibers, crimp rate: 4.7%).

[0110] Next, using a 28-gauge circular knitting machine, the false twisted crimped yarn made of the composite fiber and a polyurethane yarn (ROIKA (trade name), total fineness 22 dtex / strand) were knitted by plating (plated yarn) to form a plain stitch circular knit fabric as shown in Figure 10. The knit fabric was then dyed using a disperse dye and a hydrophilizing agent under the same conditions as in Example 6, and subjected to a final dry heat set at 160°C for 1 minute.

[0111] The resulting knitted fabric was a random mix of modified cross-section fibers made of nylon 6, which had been split from the composite fiber, and modified cross-section fibers made of 2.6 mol% 5-sodium sulfoisophthalic acid copolymerized polyethylene terephthalate, each with a V-shaped cross-section (having two protrusions), and had a deep color, a fine chambray effect, a bulky spun-like texture, and abrasion resistance. The single fiber fineness of the polyester (sodium sulfoisophthalate copolymerized polyester) fiber and polyamide (nylon 6) fiber contained in the knitted fabric was both 0.6 dtex. The evaluation results are also shown in Table 3.

[0112] (Example 8) The X-shaped conjugate fiber POY shown in Figure 1 made of nylon 6 and copolymerized polyethylene terephthalate obtained in Example 7 was false-twisted and crimped at a yarn speed of 500 m / min, a heater temperature of 155°C, and a draw ratio of 1.6 to obtain a false-twisted crimped yarn (total fineness 55 dtex / 48 yarns, crimp rate 5.7%).

[0113] Next, false twisted crimped yarns made from the composite fiber were used as warp and weft yarns, and a plain weave fabric was woven using a rapier loom with the design shown in Figure 11. The fabric was then spread and scoured at 95°C using a scouring device. It was then dyed with a disperse dye at 130°C using a jet dyeing machine, and then subjected to the following water-repellent treatment. The water-repellent treatment was carried out using the following processing agent, and the fabric was squeezed out at a pickup rate of 80%, dried at 130°C for 3 minutes, and then heat-treated at 170°C for 45 seconds. <Composition of processing agent> Non-fluorine water repellent 5.0 wt% (Nicca Chemical Co., Ltd., Neoseed NR-7080, hydrocarbon compound) Melamine resin 0.3 wt% (Sumitomo Chemical Co., Ltd., Sumitex Resin M-3) Catalyst 0.3 wt% (Sumitomo Chemical Co., Ltd., Sumitex Accelerator ACX) Water 94.4 wt%

[0114] The fabric thus obtained had a basis weight of 76.7 g / m ２ The warp density was 158 threads / 2.54 cm, the weft density was 107 threads / 2.54 cm, and the cover factor was 1874. The composite fiber was split to form modified cross-section fibers made of nylon 6 and modified cross-section fibers made of 2.6 mol% 5-sodium sulfoisophthalic acid copolymerized polyethylene terephthalate, which were randomly mixed to form a V-shaped cross-section (having two protrusions), and the fabric had a deep color, a fine chambray effect, a bulky spun texture, and abrasion resistance. The evaluation results are shown in Table 4.

[0115] Example 9 The plain weave fabric obtained in Example 8 was used and subjected to post-processing. This plain weave fabric had the structure shown in Figure 11, in which false-twisted crimped yarns made of nylon 6 and copolymerized polyethylene terephthalate X-shaped composite fibers as shown in Figure 1 were used as warp and weft yarns. The plain weave fabric was then subjected to a spread-fiber scouring treatment at 95°C using a scouring machine. It was then dyed with an acid dye and a cationic dye at 100°C using a jet dyeing machine, and then subjected to the same water-repellent treatment as in Example 8.

[0116] The fabric thus obtained had a basis weight of 86.8 g / m ２The warp density was 158 / 2.54 cm, the weft density was 140 / 2.54 cm, and the cover factor was 2107. The composite fiber was split to form a V-shaped (two-projection) cross section of modified cross section fibers made of nylon 6 and modified cross section fibers made of 2.6 mol% 5-sodium sulfoisophthalic acid copolymerized polyethylene terephthalate, which were randomly mixed, resulting in a deep color, a fine chambray effect, a bulky spun texture, and abrasion resistance. The evaluation results are also shown in Table 4.

[0117] Example 10: False-twist crimping was performed on POY (total fineness 92 dtex / 24 fibers) X-shaped composite fibers as shown in Figure 1 composed of nylon 6 and copolymerized polyethylene terephthalate under the same conditions as in Example 8, except that the number of filaments was changed from 48 to 24. False-twist crimped yarn (total fineness 55 dtex / 24 fibers, crimp rate 4.5%) was obtained under the same conditions as in Example 8. The ratio X / Y, which is the inter-polymer distance X connecting the centers of the smallest encompassing circles of the modified cross sections of each polymer component, to the bonded surface distance Y in the cross section, was 1.7.

[0118] Next, a 46-gauge circular knitting machine was used to knit a plain knitted fabric as shown in Fig. 10 using the composite fiber. The knitted fabric was then dyed using a disperse dye and a hydrophilizing agent under the same conditions as in Example 6, and subjected to a final dry heat set at 160°C for 1 minute.

[0119] The resulting knitted fabric was a random mix of modified cross-section fibers made of nylon 6, which had been split from the composite fiber, and modified cross-section fibers made of 2.6 mol% 5-sodium sulfoisophthalic acid copolymerized polyethylene terephthalate, forming a V-shaped cross-section (having two protrusions). It had a rich color, a fine chambray effect, a bulky spun-like texture, and abrasion resistance. The single fiber fineness of the polyester (sodium sulfoisophthalate copolymerized polyester) fiber and polyamide (nylon 6) fiber contained in the knitted fabric was both 1.1 dtex. The evaluation results are also shown in Table 3.

[0120] (Example 11) An X-shaped conjugate fiber (total fineness 55 dtex / 24 filaments, crimp rate 5.7%) shown in Figure 1 was obtained from nylon 6 and copolymerized polyethylene terephthalate under the same conditions as in Example 6, except that the number of filaments was changed from 48 to 24. The ratio X / Y, which is the inter-polymer distance X connecting the centers of the smallest encompassing circles of the modified cross sections of each polymer component, to the bonded surface distance Y in the cross section, was 1.7.

[0121] Next, using a 28-gauge circular knitting machine, the composite fiber was used to knit a circular knitted fabric with a smooth structure as shown in Figure 9. The knitted fabric was then dyed using a disperse dye and a hydrophilizing agent under the same conditions as in Example 6, and subjected to a final dry heat set at 160°C for 1 minute.

[0122] The resulting knitted fabric was a random mix of modified cross-section fibers made of nylon 6, which had been split from the composite fiber, and modified cross-section fibers made of 2.6 mol% 5-sodium sulfoisophthalic acid copolymerized polyethylene terephthalate, forming a V-shaped cross-section (having two protrusions). It had a rich color, a fine chambray effect, a bulky spun-like texture, and abrasion resistance. The single fiber fineness of the polyester (sodium sulfoisophthalate copolymerized polyester) fiber and polyamide (nylon 6) fiber contained in the knitted fabric was both 1.1 dtex. The evaluation results are also shown in Table 3.

[0123] Example 12 The X-shaped composite fiber (total fineness: 55 dtex / 24 strands, crimp rate: 5.7%) made of nylon 6 and copolymerized polyethylene terephthalate obtained in Example 11 was used. This composite fiber was used as the warp and weft, and a plain weave fabric was woven using a rapier loom with the structure shown in Figure 11. The fabric was then spread and scoured at 95°C using a scouring machine. It was then dyed with a disperse dye at 130°C using a jet dyeing machine, and then subjected to the same water-repellent finish as in Example 8.

[0124] The fabric thus obtained had a basis weight of 75 g / m ２The fabric had a warp density of 172 threads / 2.54 cm, a weft density of 128 threads / 2.54 cm, and a cover factor of 2153. The composite fibers were split to form irregular cross-section fibers made of nylon 6 and irregular cross-section fibers made of 2.6 mol% 5-sodium sulfoisophthalic acid copolymerized polyethylene terephthalate, which were randomly mixed to form a V-shaped cross-section (having two protrusions), resulting in a deep color, a fine chambray effect, a bulky spun-like texture, and abrasion resistance. The single fiber fineness of the polyester (sodium sulfoisophthalate copolymerized polyester) fiber and polyamide (nylon 6) fiber contained in the fabric was both 1.1 dtex. The evaluation results are also shown in Table 4.

[0125] Example 13: False-twist crimping was performed on POY (total fineness 92 dtex / 24 strands) X-shaped composite fiber as shown in Figure 1 composed of nylon 6 and copolymerized polyethylene terephthalate under the same conditions as in Example 10 to obtain a false-twist crimped yarn (total fineness 55 dtex / 48 strands, crimp rate 4.5%). The ratio X / Y, which is the ratio of the inter-polymer distance X connecting the centers of the smallest encompassing circles of the modified cross sections of each polymer component to the bonded surface distance Y in the cross section, was 1.7.

[0126] Next, false twisted crimped yarns made of the composite fiber were used as warp and weft yarns, and a plain weave fabric was woven using a rapier loom to have the design shown in Figure 11. Next, under the same conditions as in Example 9, the plain weave fabric was spread and scoured, dyed with an acid dye and a cationic dye, and then water-repellent finished.

[0127] The fabric thus obtained had a basis weight of 88.3 g / m ２The fabric had a warp density of 208 threads / 2.54 cm, a weft density of 112 threads / 2.54 cm, and a cover factor of 2251. The composite fibers were split to form irregular cross-section fibers made of nylon 6 and irregular cross-section fibers made of 2.6 mol% 5-sodium sulfoisophthalic acid copolymerized polyethylene terephthalate, which were randomly mixed to form a V-shaped cross-section (having two protrusions), resulting in a deep color, a fine chambray effect, a bulky spun-like texture, and abrasion resistance. The single fiber fineness of the polyester (sodium sulfoisophthalate copolymerized polyester) fiber and polyamide (nylon 6) fiber contained in the fabric was both 1.1 dtex. The evaluation results are also shown in Table 4.

[0128] Example 14 Nylon 6 (low glass transition point) and 2.6 mol% 5-sodium sulfoisophthalic acid copolymerized polyethylene terephthalate (η = 0.55, high glass transition point) were spun at a spinning temperature of 265°C and wound at a spinning speed of 2500 m / min to obtain a composite fiber having a side-by-side cross-sectional shape (weight ratio of both components: 50:50) as shown in Figure 4. This composite fiber was preheated and drawn at 90°C, heat-set using a 180°C slit heater, and wound at a winding speed of 600 m / min to obtain a yarn with a total fineness of 55 dtex / 24 yarns (crimp rate: 13.3%). The ratio X / Y, which is the ratio of the inter-polymer distance X connecting the centers of the smallest encompassing circles of the modified cross sections of each polymer component to the joint surface distance Y in the cross section, was 2.3.

[0129] Next, the composite fibers were arranged in the warp and weft, and a plain weave fabric was woven using a rapier loom with the design shown in Figure 11. The plain weave fabric was then spread and scoured under the same conditions as in Example 12, and dyed with a disperse dye at a temperature of 130°C. As in Example 12, the same water-repellent finish as in Example 8 was applied.

[0130] The fabric thus obtained had a basis weight of 78 g / m ２The fabric had a warp density of 180 threads / 2.54 cm, a weft density of 134 threads / 2.54 cm, and a cover factor of 2209. The composite fiber was split to form irregular cross-section fibers made of nylon 6 and irregular cross-section fibers made of 2.6 mol% 5-sodium sulfoisophthalic acid copolymerized polyethylene terephthalate, which were randomly mixed to form rectangular cross-sections, resulting in a deep color, a fine chambray effect, a bulky spun texture, and abrasion resistance. The single fiber fineness of the polyester (sodium sulfoisophthalate copolymerized polyester) fiber and polyamide (nylon 6) fiber contained in the fabric was both 1.1 dtex. The evaluation results are also shown in Table 4.

[0131] Comparative Example 4 Using polyethylene terephthalate false twist crimped yarn (semi-dull) with a total fineness of 66 dtx / 48 strands, a circular knitted fabric with a smooth structure shown in FIG. 9 was knitted using a 28-gauge circular knitting machine.

[0132] The knitted fabric was then dyed using a disperse dye at 130°C for 15 minutes. A hydrophilizing agent (polyethylene terephthalate-polyethylene glycol copolymer) was added to the knitted fabric at a ratio of 2 ml / l of the dye liquor during dyeing, thereby providing the hydrophilizing agent to the knitted fabric. The circular knitted fabric was then subjected to a final dry heat set at 160°C for 1 minute. The resulting knitted fabric had excellent water absorption and quick-drying properties, but was a solid color and did not have a chambray appearance. The evaluation results are also shown in Table 3.

[0133] Comparative Example 5 A polyester crimped yarn having a total fineness of 38 dtex / 36 strands (semi-dull, twist S: 300 t / m, yarn A) and a polyester crimped yarn having a yarn strength of 4.9 cN / dtex and a total fineness of 33 dtex / 36 strands (bright, twist Z: 300 t / m, high-strength yarn B) were arranged in a 7:2 warp yarn arrangement, and a polyester crimped yarn having a yarn strength of 4.9 cN / dtex and a total fineness of 33 dtex / 36 strands (bright, twist Z: 300 t / m, high-strength yarn B) was arranged as a weft yarn. A plain weave fabric was woven using a rapier loom to have the design shown in FIG.

[0134] The plain woven fabric was then subjected to a spread scouring treatment under the same conditions as in Example 12, and dyed with a disperse dye at a temperature of 130°C. As in Example 12, the same water-repellent treatment as in Example 8 was applied. The fabric thus obtained had a basis weight of 59.6 g / m ２ The warp density was 165 threads / 2.54 cm, the weft density was 130 threads / 2.54 cm, and the cover factor was 1667. The color was monochrome, and no chambray appearance was obtained. The evaluation results are also shown in Table 4.

[0135]

[0136]

[0137] (Discussion) The results obtained from Examples 1 to 5 and Comparative Examples 1 to 3 are further detailed below. In Examples 1 to 4, two polymers with different glass transition temperatures were combined and bonded to form a modified cross section. The ratio X / Y (the inter-polymer distance X to the bond distance Y) of each component was 1.1 or greater, resulting in a high crimp rate. Furthermore, when one of the components was nylon 6, significant changes in the crimp morphology were observed upon elongation in boiling water. As a result, the components underwent reversal of the inside and outside of the crimp coil, resulting in peeling at the bonded interface, splitting, and mixing and rearrangement of the dyed components. Two types of modified cross-section fibers separated from the modified side-by-side composite cross-section fiber were observed on the fabric surface. The crimp morphology of Example 1, as shown in Figure 7, exhibited a large crimp coil size.

[0138] Example 5 was made with an even finer fineness than Example 1, and the softness of the finer fineness gave it a comfortable feel. In addition, the mixed effect of the finer fineness produced deep shadows and a chambray effect.

[0139] Comparative Example 1 was a conventionally known side-by-side cross-section fiber made by bonding together two semicircular pieces. The distance X between the two polymer components was 0 (zero), and the distance between their centers of gravity was also shorter than the bonded surface distance Y, resulting in a small crimped shape and a small change in length before and after boiling water treatment. Therefore, there were almost no split fibers, and the blending effect in the fabric was not achieved. The crimped shape of Comparative Example 1 was a small crimped coil size, as shown in Figure 8.

[0140] Comparative Example 2 was a side-by-side cross section made by bonding together triangular cross sections, and although it had one protrusion, the bonded surface distance Y was longer than the distance X between the two component polymers, so the fabric lacked separability, with some areas showing two components and others showing only one component. The divided and undivided areas created an uneven shape on the fabric surface, and the fabric was of poor quality.

[0141] In Comparative Example 3, the polymer composition was the same, and large crimping properties were obtained due to the difference in molecular weight and cross-sectional shape. However, since nylon 6 was not used, the change in crimping morphology before and after boiling water treatment was small, and splitting and mixability were not obtained.

[0142] The present invention provides a modified side-by-side composite cross section fiber that is excellent in processability. From the modified side-by-side composite cross section fiber, a modified cross section fiber suitable for improving the quality of fabrics can be obtained, resulting in fabrics with good texture and unique appearance.

[0143] X: Distance between the centers of the smallest encompassing circles of each polymer component (inter-polymer distance) Y: Length of the interface between different polymer components (inter-interface distance)

Claims

1. A heteromorphic side-by-side composite cross-section fiber comprising two polymers with different glass transition temperatures, wherein the cross-sectional shapes of the polymer components are heteromorphic, and the ratio X / Y, which is the interpolymer distance X connecting the centers of the minimum inclusion circles of the heteromorphic cross-sections of each polymer component to the bonding surface distance Y in the cross-section, is 1.1 or greater, and the two polymers are composed of a polyamide polymer and a copolymerized polyester polymer.

2. The heteromorphic side-by-side composite cross-section fiber according to claim 1, wherein the cross-sectional shape of the polymer component has two or more protruding shapes relative to the bonding surface of each polymer.

3. The irregularly shaped side-by-side composite cross-section fiber according to claim 1, which is a crimped fiber.

4. The heteromorphic side-by-side composite cross-section fiber according to claim 1, wherein the polyamide polymer is a nylon 6 polymer.

5. The heteromorphic side-by-side composite cross-section fiber according to claim 1, wherein the copolymerized polyester polymer is a sodium sulfisophthalate copolymerized polyester.

6. The irregular side-by-side composite cross-section fiber according to claim 1, wherein the two polymers consist of a nylon 6 polymer and a copolymerized polyester polymer, and the nylon 6 polymer is positioned on the inside of the three-dimensional crimped fiber.

7. The present invention relates to a heteromorphic side-by-side composite cross-section fiber according to claim 6, wherein the nylon 6 polymer inside the three-dimensional crimped coil self-extends in a hot water bath at a temperature of 80°C or higher, changing from a three-dimensional crimped structure to a linear fiber form, and then, upon removal from the hot water bath, the fiber returns to a three-dimensional crimped state as the fiber temperature decreases and the absorbed water dries, and the elongation change rate (Equation 1) after 30 minutes of boiling water treatment is 130 to 200%. Elongation change rate: (Length after hot water treatment - Length when dry) / Length when dry × 100 (%) Equation 1 (However, all length measurements are based on a light load applied using a skein fineness (dtex) × 2 mg / dtex.)

8. The irregular side-by-side composite cross-section fiber according to claim 6, wherein the nylon 6 polymer inside the three-dimensional crimped coil self-extends in a hot water bath at a temperature of 80°C or higher, causing the bonding surface to peel off when the structure changes from a three-dimensional crimped structure to a linear fiber form.

9. The irregularly shaped side-by-side composite cross-section fiber according to claim 6, wherein in a hot water bath at a temperature of 80°C or higher, the nylon 6 polymer on the inside of the three-dimensional crimped coil reverses to its configuration on the outside of the three-dimensional crimped coil by self-extension, and the bonding surface peels off.

10. A method for producing a heteromorphic side-by-side composite cross-section fiber, comprising two polymers with different glass transition temperatures, wherein the cross-sectional shapes of the polymer components are heteromorphic, and the ratio X / Y, which is the ratio of the interpolymer distance X connecting the centers of the minimum inclusion circles of the heteromorphic cross-sections of each polymer component to the joint surface distance Y in the cross-section, is 1.1 or more, characterized by peeling off the joint surface of the heteromorphic side-by-side composite cross-section fiber.

11. A method for producing irregularly shaped cross-section fibers according to claim 10, wherein the peeling method is a hot water shrinkage treatment.

12. A method for manufacturing a fabric, characterized by using a heteromorphic side-by-side composite cross-sectional fiber composed of two polymers with different glass transition temperatures, wherein the cross-sectional shapes of the polymer components are heteromorphic, and the ratio X / Y, which is the ratio of the interpolymer distance X connecting the centers of the minimum inclusion circles of the heteromorphic cross-sections of each polymer component to the bonding surface distance Y in the cross-section, is 1.1 or greater, to form a sheet, and then peeling off the heteromorphic side-by-side composite cross-sectional fiber.

13. A method for producing a fabric according to claim 12, wherein the two polymers having different glass transition temperatures are polyester and polyamide.

14. The method for producing a fabric according to claim 12, wherein the different cross-sectional shapes of each polymer are the same cross-sectional shape.

15. A method for producing a fabric according to claim 12, wherein the single fiber fineness of each component after peeling is 2.0 dtex or less.

16. The weight of the fabric is 30-300 g / m ２ The fabric according to claim 12, which is within the range.

17. The method for manufacturing a fabric according to claim 12, wherein the fabric is a knitted fabric having a density of 50 to 120 courses per 2.54 cm and 40 to 100 wales per 2.54 cm.

18. A method for manufacturing a fabric according to claim 12, wherein the fabric is a woven fabric, and the warp density is 50 to 300 threads / 2.54 cm and the weft density is 50 to 300 threads / 2.54 cm.

19. A method for manufacturing a woven fabric according to claim 12, wherein the woven fabric has abrasion resistance of 30,000 cycles or more according to the Martindale method of JIS L1096.