Island-in-the-sea type composite fiber and fabric made therefrom

Abstract

To provide a sea-island composite fiber used as a raw material for fabric having soft touch peculiar to ultrafine fibers, having both of tensile strength and toughness and having abrasion resistance.SOLUTION: The sea-island type composite fiber has two different diameters of island components constituting the sea-island type composite fiber; a thick fineness island component has a diameter of 5 to 20 μm, and a thin fineness island component has a diameter of 10 to 2000 nm; the number of the thin fineness island components is 25 times or more and 500 times or less of that of the thick fineness island component; and the island component occupies 40 wt.% or more in the sea-island type composite fiber. Moreover, it is preferable that: the thick fineness island component is positioned at a central part in one filament of the composite fiber; thin fineness components are arranged uniformly on a peripheral circumference of the thick fineness island component; the number of the thick fineness island components is 3 or less in one filament of the sea-island composite fiber; the thin fineness island component is flat extending in a radial direction, and a deformation degree thereof is 1.2 to 5.0; and the sea-island type composite fiber is composed of a multifilament.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to islands-in-the-sea type composite fibers and fabrics made thereof. [Background technology]

[0002] As a means for imparting softness to fibers, a method of imparting a fluffy appearance to the surface of a woven or knitted fabric is known. For example, a method has been proposed in which fibers made of polyester to which an organic sulfonic acid metal salt or the like has been added are made into a woven or knitted fabric, and the surface of the woven or knitted fabric is subjected to an alkali treatment and then a buffing treatment, or the buffing treatment is followed by an alkali hydrolysis treatment to microfibrillate the polyester fibers and form fluff on the surface of the woven or knitted fabric (e.g., Patent Document 1), and a method has been proposed in which fibers made of polyester to which a long-chain organic compound incompatible with polyester and / or an organic sulfonic acid metal salt has been added into a woven or knitted fabric, and the woven or knitted fabric is subjected to a concave-convex or embossing treatment or the like in combination with an alkali treatment to partially fibrillate the polyester fibers on the surface of the woven or knitted fabric (e.g., Patent Documents 2 and 3).

[0003] However, the method of blending an incompatible long-chain organic compound and / or an organic metal sulfonate into the above-mentioned polyester to fibrillate part of the fiber surface had problems with quality stability, such as the occurrence of spots during mass production.

[0004] On the other hand, as a method for forming ultrafine fibers not only on the surface but also over the entire surface, a method using an "island-in-sea type composite fiber" in which a plurality of island component polymers that are substantially continuous in the fiber axial direction are independently present in a sea component polymer is known. Such islands-in-sea type composite fibers are widely used as a constituent material for nonwoven fabrics and woven fabrics because ultrafine fiber bundles made of island components can be obtained by removing only the sea component after spinning. In particular, they are useful as leather-like sheet materials such as artificial leather and artificial leather-like woven fabrics.

[0005] To produce such ultrafine fibers, a method is generally adopted in which a sea-island fiber produced by a composite spinning method is subjected to a sea-removal process to produce ultrafine fibers. In this technique, a plurality of island components made of slightly soluble components are arranged in a sea component made of a soluble component in the fiber cross section. After producing this composite fiber or a textile product, the sea component is removed to produce ultrafine fibers made of island components.

[0006] In particular, nanofibers with a single fiber diameter of several hundred nanometers have an increased specific surface area (surface area per weight) and material flexibility, resulting in unique properties that cannot be obtained with general-purpose fibers or microfibers. For example, the reduced fiber diameter increases the contact area and increases wiping performance due to the dirt capture effect. In addition, the effects of the ultra-specific surface area include gas adsorption performance, a unique soft touch (slippery feel), and improved water absorption due to fine voids. Taking advantage of these properties, nanofibers are used in artificial leather and textiles with new textures in apparel, and the dense fiber spacing is used in sportswear that requires wind resistance and water repellency.

[0007] However, when such nanofibers are used throughout the fabric, there is a problem that the fabric becomes excessively flexible. It is easy for the fabric to lose tension or stiffness and not be able to maintain its shape. It is difficult to produce a fabric suitable for practical use in terms of mechanical properties. Furthermore, there is a problem that the processability is significantly reduced in post-processing such as sea-removal treatment in which the sea component is dissolved with a solvent and weaving and knitting in order to produce ultrafine fibers from sea-island fibers.

[0008] In the technology of Patent Document 4, a blended yarn is made of a fiber with a large fiber diameter and a sea-island fiber, and this blend A technology has been proposed in which sea-removal processing is carried out after weaving and knitting of fiber yarns. With this technology, the mechanical properties (e.g., tension and stiffness) of the fabric are provided by the fibers with larger fiber diameters, and the mechanical properties of the fabric can be improved compared to nanofibers alone. However, with this technology, the fibers with larger fiber diameters and the sea-island fibers tend to be unevenly distributed at the blending stage, which causes a large bias in the number of ultrafine fibers in the cross-sectional and planar directions of the final fabric, resulting in large local variations in mechanical properties (tension, stiffness, etc.) and moisture absorption, and the high density of ultrafine fibers increases friction between the fibers, causing wear and breakage of the ultrafine fibers. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 58-298457 [Patent Document 2] Japanese Patent Application Publication No. 7-197375 [Patent Document 3] Japanese Patent Application Publication No. 11-36181 [Patent Document 4] JP 2008-248445 A Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention has been made in consideration of the above-mentioned background, and an object of the present invention is to provide an islands-in-sea type composite fiber which has excellent processability, and from which a fabric obtained has the soft touch peculiar to ultrafine fibers and also has tension and stiffness, and a fabric made thereof. [Means for solving the problem]

[0011] The islands-in-the-sea type composite fiber of the present invention is The island component is made of polyethylene terephthalate and the sea component is made of copolymerized polyethylene terephthalate. The diameters of the island components constituting the islands-in-sea type composite fiber are of two or more kinds, the diameters of the large-fineness island components being 5 μm to 20 μm, the diameters of the fine-fineness island components being 10 to 2000 nm, and The fine island component is flat and elongated in the radial direction, and the irregularity degree is 1.2 to 5.0.The number of the island components is 25 to 500 times the number of the large-fineness island components, and the island components account for 40% by weight or more.

[0012] Furthermore, the large-fineness island component is located at the center of one filament of the composite fiber, the small-fineness components are evenly arranged around the large-fineness island component, and the number of large-fineness island components in one filament of the sea-island composite fiber is 3 or less. Ya, Ma It is preferable that the fiber is made of multifilaments. A further aspect of the present invention is a fabric comprising the large-fineness fibers and the small-fineness fibers derived from the islands-in-the-sea type composite fibers. Effect of the Invention

[0013] According to the present invention, it is possible to provide an islands-in-sea type composite fiber which is a fiber with excellent processability, and a fabric obtained by using the fiber has a soft touch specific to ultrafine fibers and also has tension and stiffness, and a fabric made thereof. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram showing an example of an islands-in-the-sea type composite fiber of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The present invention will be described in detail below. In the present invention, the island component polymer is not particularly limited, but preferable examples thereof include melt-moldable polymers such as polyethylene terephthalate and copolymers thereof, polyethylene naphthalate, polybutylene terephthalate, polytrimethylene terephthalate, polypropylene, polyolefin, polycarbonate, polyacrylate, polyamide, and polylactic acid.

[0016] In this case, the polymer may contain various additives such as inorganic substances such as titanium oxide, silica, barium oxide, etc., colorants such as carbon black, dyes, pigments, etc., flame retardants, fluorescent brighteners, antioxidants, or ultraviolet absorbing agents.

[0017] Examples of the sea component polymer include polymers that can be melt-molded and can be dissolved and extracted after spinning, such as copolymerized polyethylene terephthalate, polyamide, polystyrene and its copolymers, polyethylene, and polyvinyl alcohol.

[0018] In addition, to produce a fabric that has the soft touch characteristic of ultrafine fibers and also has tension and stiffness, it is preferable that the island components constituting the fine island components are arranged around the thick island component core. That is, by surrounding the thick island component core with a fiber diameter of 5 μm to 20 μm with fine island components with a fiber diameter of 10 to 2000 nm, a higher level of the soft touch characteristic of ultrafine fibers and the tension and stiffness of the fabric can be obtained. The fiber diameter range specified here means that both the shortest and longest diameters of the fiber components are within that range.

[0019] The fiber diameter of the thick-fineness island component in the present invention is 5 μm to 20 μm. If the fiber diameter is less than 5 μm, the texture of the fabric becomes too soft, which is not preferable. On the other hand, if the fiber diameter is more than 20 μm, it is difficult to uniformly disperse the ultrafine fibers around the thick-fineness fibers after weight reduction processing, and the smooth texture unique to ultrafine fibers is lost, which is not preferable. Furthermore, the fiber diameter is preferably in the range of 8 μm to 15 μm. In addition, it is preferable that the thick-fineness island component is located at the center of one filament of the composite fiber, and a fabric with excellent texture can be obtained. The thick-fineness island component may be a collection of multiple island components, but it is more preferable that it is composed of one island component.

[0020] Furthermore, in the sea-island composite fiber of the present invention, the diameter of the fine island component fibers is 10 to 2000 nm. If the diameter of the fine island component fibers is less than 10 nm, whitening occurs due to diffuse reflection, which is problematic in terms of quality. If the diameter of the fine island component fibers is greater than 2000 nm, the soft touch of ultrafine fibers cannot be obtained, which is undesirable. Furthermore, the diameter is preferably in the range of 200 to 1800 nm.

[0021] The number of fine island components is preferably 25 to 500 times, more preferably 30 to 250 times, the number of large island components. The fine island components are preferably arranged around the large island components, and such an arrangement allows the fabric after the sea component is removed to have abrasion resistance in addition to the soft touch and tension characteristic of ultrafine fibers. For example, when there are less than 25 times as many fine island components around the large island components, the large island components are easily exposed, which is not preferable because the soft touch characteristic of ultrafine fibers cannot be obtained. When there are more than 500 times as many fine island components around the large island components, the fine island components are in close contact with each other, or the friction increases due to the excessive number of fine island components, which is not preferable because the abrasion resistance decreases.

[0022] In addition, the shape of the fine island component that later forms the ultrafine fiber in the islands-in-the-sea type fiber is flat and long in the radial direction of the islands-in-the-sea fiber. Necessary Furthermore, the degree of atypicality in the flat section was 1.2 to 5.0. Necessary Here, the irregularity refers to the ratio of the long diameter to the short diameter (long diameter / short diameter) of the cross section of the island component that becomes ultrafine fiber after flattening. When the fiber shape becomes flat in cross section, the contact area becomes larger than that of a round cross section, resulting in the softness characteristic of ultrafine fibers. However, if the island component irregularity is too large, the strength of the fine island component decreases, and it tends to become fibrillated and whitened, causing quality problems.

[0023] In addition, the number of large-fineness island components is preferably 3 or less. If the number is too large, it is difficult to uniformly disperse the ultrafine fibers around the large-fineness fibers after weight reduction processing, or the texture of the fabric becomes too soft, which is not preferable. Furthermore, the number of large-fineness island components is most preferably 1.

[0024] The large-fineness island component and the small-fineness island component in the sea-island composite fiber can be merged with the sea component to form a composite cross section by designing the extrusion holes so as to realize a fineness difference. In sea-island composite fibers, the weight ratio of sea:island components is preferably 6:4 to 1:9. If the ratio of the sea component is large, the amount of sea polymer component that is reduced increases, and the fabric becomes excessively low density, and the intervals between the warp and weft yarns may become disordered, making it difficult to obtain tension and stiffness, which is undesirable. Conversely, if the ratio of the sea component is small, it is undesirable because poor division occurs, such as the island components sticking together in the cross section of the sea-island composite fiber.

[0025] In addition, when the distance between the fine island components and the coarse island components is H and the distance between the fine island components is h, it is preferable that h≦H≦20h. Furthermore, it is preferable that H is 10h or less, and more preferable that 1.2h≦H≦5h. If H is too large, it is difficult for the fine island components to be uniformly dispersed around the coarse island components during weight reduction processing, and the smooth feel that is unique to ultrafine fibers is lost, which is not preferable. Furthermore, if H is large, the ultrafine fibers are unevenly distributed and gather together, and the friction between the ultrafine fibers causes many thread breaks, which reduces the abrasion resistance. If H is too small, for example, if it is smaller than h, the distance between the fine island components and the coarse island components becomes too narrow, causing partial fusion, which is not preferable because the soft feel of ultrafine fibers cannot be obtained.

[0026] In addition, the distance c between the outer diameter of the sea-island composite fiber and the fine island component fibers is preferably 0.01a≦c≦3a, where a is the major axis of the fine island component fibers. It is further preferable that c is a distance equal to or less than a. If the distance c between the outer diameter of the sea-island composite fiber and the fine island component fibers is too small, this is not preferable because it may cause yarn breakage and scum during spinning. Also, if the distance c between the outer diameter of the composite fiber and the fine island component fibers is too large, this is not preferable because fusion between the island components may occur during formation of the sea-island composite fiber, since the distance between the thick-core island component fibers and the fine island component fibers and between the fine island components themselves becomes too short.

[0027] In addition, the distance h between the ultrafine fiber components is preferably 0.1b≦h≦10b, more preferably 0.2b≦h≦5b, where b is the short diameter of the ultrafine fiber. If the distance h between the ultrafine fiber components is smaller than 0.1b, the distance between the ultrafine fiber components becomes too small, causing fusion between the ultrafine fiber components, which is not preferred because ultrafine fibers cannot be formed after reduction and the smooth feel that is unique to ultrafine fibers is lost. If the distance h between the ultrafine fiber components is larger than 10b, it is difficult for the fine island components to be uniformly dispersed around the thick island components, which is not preferred because the smooth feel that is unique to ultrafine fibers is lost after reduction of the sea component.

[0028] The sea-island composite fiber of the present invention is composed of the above-mentioned single yarns (filaments), but it is preferable to use it as a yarn consisting of multiple single yarns (filaments). By using it in the form of a yarn consisting of multiple single yarns, not only will the texture of the obtained fabric become softer, but the processability will also be improved. When the sea-island composite fiber is made into a yarn, the fiber fineness, number of filaments and total fineness are preferably in the ranges of single fiber fineness 0.5 to 10.0 dtex, number of filaments 5 to 75 and total fineness 30 to 170 dtex (preferably 30 to 100 dtex), respectively.

[0029] Another fabric of the present invention is made using the above-mentioned sea-island composite fiber. It is most preferable that the fabric is made only of the sea-island composite fiber, and it is preferable that the sea-island composite fiber accounts for 30% by weight or more (more preferably 50% by weight or more) of the fabric weight. As a mixing method, other fibers may be mixed into one yarn, or it is also preferable to use the sea-island composite fiber in combination with another yarn not containing the sea-island composite fiber in a woven or knitted fabric.

[0030] The fabric using the sea-island composite fiber thus obtained preferably has a friction resistance of at least 2 N. Since the yarn surface in the fabric is constituted by ultrafine fibers and the friction resistance is at least 2 N, the fabric has a unique softness and excellent quality.

[0031] In addition, in order to evaluate the abrasion resistance of the fabric of the present invention, it is preferable that after testing using JIS L10968.17.3 C method (Taber method, abrasion wheel CS-10, load 4.90 N (500 gf), 1,000 times), the change in fabric surface quality (shininess) after the test is grade 3 or higher.

[0032] The sea-island composite fiber of the present invention can be produced, for example, by the following method. First, the above-mentioned polymer is prepared as the island component polymer (polymer forming the ultrafine fibers and the central fiber). In this case, the above-mentioned polymer may contain various additives such as inorganic substances such as titanium oxide, silica, barium oxide, etc., colorants such as carbon black, pigments, dyes, etc., flame retardants, fluorescent brighteners, antioxidants, and ultraviolet absorbers.

[0033] Examples of the sea component polymer include polymers that can be melt-molded and dissolved and extracted after spinning, such as copolymerized polyethylene terephthalate, polyamide, polystyrene and its copolymers, polyethylene, and polyvinyl alcohol. In this case, the weight ratio of the two components forming the composite fiber, that is, the sea:island component ratio, is preferably 6:4 to 1:9. If the ratio of the sea component is large, the amount of sea polymer component that is reduced increases, and the fabric becomes excessively low density, and the intervals between the warp and weft yarns may become disordered, and tension and stiffness cannot be obtained, which is not preferable. Conversely, if the ratio of the sea component is small, it is not preferable because poor division occurs, such as the island components adhering to each other in the cross section of the sea-island composite fiber.

[0034] Next, each component is discharged from a spinneret having discharge holes for discharging the island components for large fine fibers (preferably 1 to 3, particularly preferably 1), the island components for ultrafine fibers (preferably 10 or more, more preferably 30 to 100) arranged radially (satellite-like) around the island components for large fine fibers, and the sea component.

[0035] The extruded islands-in-the-sea composite fiber is solidified by cooling air, and is preferably melt-spun at 400 to 6000 m / min and then wound up. The undrawn yarn obtained may be subjected to a separate drawing process to produce a composite fiber having desired strength, elongation and heat shrinkage properties, or may be taken up on a roller at a constant speed without being wound up, and then subjected to a drawing process before being wound up. Furthermore, false twist crimping may be performed. In such islands-in-the-sea composite fiber, the single fiber fineness, the number of filaments and the total fineness are preferably within the ranges of 0.5 to 10.0 dtex, 5 to 75 filaments and 30 to 170 dtex (preferably 30 to 100 dtex), respectively.

[0036] The thus obtained sea-island composite fiber of the present invention can be made into a woven or knitted fabric, and then the sea component of the islands-in-sea type composite fiber can be subjected to a sea-removal treatment to produce another fabric of the present invention. A fabric produced using such a conjugate fiber of the present invention has the soft touch characteristic of ultrafine fibers, and also has tension and stiffness, and is excellent in wear resistance and processability. EXAMPLES

[0037] Next, examples and comparative examples of the present invention will be described in detail, but the present invention is not limited to these. In the examples, the respective items were measured by the following methods.

[0038] (1) Melt Viscosity The polymer after drying is set in an orifice set to the melting temperature of the ruder during spinning, and kept molten for 5 minutes. Then, it is extruded under several load levels, and the shear rate and melt viscosity at that time are plotted. The plots are smoothly connected to create a shear rate-melt viscosity curve, and the shear rate is 1000 s -1 Check the melt viscosity at this time.

[0039] (2) Sea-island type composite fiber island component diameter (thick core island component diameter: R, fine fineness island component, major axis: a, short axis: b), distance between thick core island component - fineness island component (H), distance between fineness island component (h), sea-island composite fiber outer diameter - distance between fineness island component (c) Using a transmission electron microscope (TEM), photographs of the fiber cross sections were taken at a magnification of 30,000 times, and the following values ​​were calculated. The island component diameter (R) is the average value of 10 filaments. The long axis: a and short axis: b of the fine island component are the average values ​​of the fine island component contained in the five filaments. In this case, the long axis and short axis are the long axis and short axis values ​​of the diameter of the circumscribed circle after assuming a circumscribed circle for each single ultrafine fiber yarn, and the ratio of the long axis to the short axis (long axis / short axis) is the irregularity. The distance between the thick-core island component and the fine-fineness island component (H), the distance between the fine-fineness island component (h), and the outer diameter of the sea-island composite fiber and the distance between the fine-fineness island component (c) are the average values ​​of the smallest values ​​of each filament among 10 filaments.

[0040] (3) Friction of textile fabrics Weight 40g / m 2 A circular knit was made so that the sample was 100 mm long and 50 mm wide, and a 100g weight was placed on it and pulled over a dry silicone plate. The friction when the load moved was measured.

[0041] (4) Abrasion resistance evaluation Abrasion resistance is evaluated by testing according to JIS L10968.17.3 C method (Taber method, abrasion wheel CS-10, load 4.90N (500gf), 1,000 times), and then observing the change in fabric surface quality (shininess) after the test. It is judged according to the following grades, and a grade of 3 or higher is preferable. Grade 5: No change. Grade 4: There is a slight shine, but it is barely noticeable. Grade 3: A little shiny, but not noticeable. Grade 2: There is a strong sense of shine and changes in surface quality are noticeable. Grade 1: The shine is very strong and the change in surface quality is so great that it is very bothersome.

[0042] [Example 1] A sea-island composite fiber of 46 dtex composed of 27 filaments was spun. The island component of the sea-island composite fiber was polyethylene etherephthalate (manufactured by Teijin Limited) with a melt viscosity of 100 Pa·s at 270°C, and the sea component of the sea-island composite fiber was polyester (modified PET1) with a melt viscosity of 150 Pa·s at 270°C, copolymerized with 3% by weight of polyethylene glycol (PEG) with a molecular weight of 4000, 9 mol% of 5-sodium sulfoisophthalic acid (SIP), and ethylene glycol (EG) as a dialcohol component. In each filament of the sea-island composite fiber, the weight ratio of the sea:island was 20:80, and the island component was a sea-island composite fiber composed of one thick island component as a core and 50 very fine island components arranged radially around it in the sea component that was later reduced and removed. Each filament of the sea-island composite fiber was discharged from 27 discharge holes, and a sea-island composite fiber composed of 27 filaments was spun. Further 1000m The filaments were wound at a speed of 100 / min and stretched 3.5 times to produce a sea-island composite fiber with 46 dtex 27 filaments. In each filament, the diameter of the thick island component that serves as the core was a perfect circle with a diameter of 10 μm, and the irregularity of the fine island component that surrounds it was an ellipse with a degree of irregularity of 1.7 (major axis 1 μm, minor axis 0.6 μm). Then, using only this 46 dtex 27 filament sea-island composite fiber, a fiber with a basis weight of 40 g / m was produced. 2 A plain knit was produced and scoured. It was then immersed in a 4% by mass NaOH aqueous solution at 80°C for 2 minutes to reduce the weight by 20% by mass using an alkali to remove the sea component, and then dried to obtain the fabric of the present invention. The fabric had a basis weight of 35 g / m 2 The physical properties and quality of the obtained fabric were measured. The results are shown in Table 1. The fabric of the present invention after weight reduction had firmness and an excellent feel.

[0043] [Example 2] The same raw materials as those in Example 1 were used for the sea-island composite fiber, and the sea:island ratio in one filament was the same at 20:80, except that in each filament, 35 ultrafine island components were arranged radially around one large-core island component. The filaments were extruded from 27 extrusion holes in the same manner as in Example 1. Then, the filaments were wound at 1000 m / min and stretched 3.5 times to produce a sea-island composite fiber having 72 dtex and 27 filaments. In this case, the diameter of the large-core island component in one filament was a perfect circle with a diameter of 12 μm, and the diameter of the surrounding small-core island component was an ellipse with a major axis of 1.6 μm and a minor axis of 0.9 μm and an irregularity degree of 1.8. The other conditions were the same as in Example 1, and a sea-island composite fiber and a fabric obtained by using the same were obtained. The fabric after weight reduction had a firmness and was excellent in texture.

[0044] [Example 3] The same raw materials as those in Example 1 were used for the sea-island composite fiber, except that the sea:island ratio in one filament was changed to 50:50, and 200 ultrafine island components were arranged radially around one thick-core island component to produce a sea-island composite fiber filament, which was extruded from 27 extrusion holes. The filament was then wound at 1000 m / min and stretched 3.5 times to produce a sea-island composite fiber with 72 dtex and 27 filaments. At this time, the diameter of the thick-core island component was 12 μm, and the irregularity of the surrounding fine island component was 1.3, and the shape was an ellipse with a major axis of 0.5 μm and a minor axis of 0.4 μm. The rest of the process was the same as in Example 1. The fabric after the weight reduction process had tension and was excellent in texture.

[0045] [Comparative Example 1] The same raw materials as in Example 1 were used for the sea-island composite fiber, and the diameter of the thick-core island component was changed from 10 μm to 3 μm, in the same manner as in Example 1. A filament in which 50 ultra-fine island components were arranged radially around one thick-core island component with a sea:island ratio of 20:80 in one filament was extruded from 27 extrusion holes. The filament was then wound at 1000 m / min and stretched 3.5 times to produce a sea-island composite fiber with 30 dtex 27 filaments. The diameter of the thick-core island component in the center was 3 μm, and the irregularity of the surrounding fine island components was 1.8, and the shape was an ellipse with a major axis of 1.6 μm and a minor axis of 0.9 μm. A fabric was produced in the same manner as in Example 1, and the physical properties were evaluated. The fabric after weight reduction had no tension.

[0046] [Comparative Example 2] The same raw materials as in Example 1 were used for the sea-island composite fiber, except that the sea:island ratio in one filament was 70:30, and 50 ultra-fine island components were radially arranged around one thick-core island component, and the filaments were extruded from 27 extrusion holes. The filaments were then wound at 1000 m / min and stretched 3.5 times to produce a sea-island composite fiber with 125 dtex and 27 filaments. At this time, the diameter of the central thick-core island component was 10 μm, and the irregularity of the surrounding fine island components was 1.7, and the shape was an ellipse with a major axis of 1 μm and a minor axis of 0.6 μm. A fabric was produced in the same manner as in Example 1, and the physical properties were evaluated. The fabric after weight reduction had no tension and was poor in abrasion resistance. I did.

[0047] [Comparative Example 3] The same raw materials as those in Example 1 were used for the sea-island composite fiber, and filaments in which the sea:island ratio in one filament was 20:80, but 20 very fine island components were arranged radially around one large-core island component, were discharged from 27 discharge holes. Then, the filaments were wound at 1000 m / min and stretched 3.5 times to produce a sea-island composite fiber with 63 dtex and 27 filaments. At this time, the diameter of the central large-core island component was 10 μm, and the irregularity of the surrounding small-core island components was 1.8, and the shape was an ellipse with a major axis of 2.5 μm and a minor axis of 1.4. The fabric was produced in the same manner as in Example 1, and the physical properties were evaluated. Although the fabric after the weight reduction process had tension and stiffness, it was a fabric with a stiff feel.

[0048] [Comparative Example 4] The same raw material as in Example 1 was used for the sea-island composite fiber, and the irregularity of the ultrafine island fiber components around the core was changed to 5.5, with a major axis of 4.4 μm and a minor axis of 0.8 μm, and the same procedure as in Example 1 was used to extrude filaments in which 20 ultrafine island fiber components were radially arranged around one core thick-fine island component, with a sea:island ratio of 20:80 in one filament. At this time, the fine island extrusion holes were slit-shaped, and the cross section of the fine island component was flat. After extrusion, the filaments were wound at 1000 m / min and stretched 3.5 times to produce sea-island composite fibers with 62 dtex 27 filaments. At this time, the diameter of the central thick-fine island component was 10 μm, and the irregularity of the peripheral fine island components was 5.5, with an elliptical shape with a major axis of 4.4 μm and a minor axis of 0.8 μm. Other than that, fabrics were prepared and their physical properties were evaluated in the same manner as in Example 1. Although the fabric after weight reduction had tension, it had a hard texture and was poor in abrasion resistance.

[0049] [Comparative Example 5] The same raw materials as those in Example 1 were used for the sea-island composite fiber, and although the sea:island ratio in one filament was 30:70, there were no large-fine island components as in the Example, and 836 ultrafine island components were uniformly arranged. The filaments were then extruded from 10 extrusion holes. They were then wound at 1000 m / min and stretched 4 times to obtain islands-in-sea composite fibers. As a result, a sea-island composite fiber was produced that had 56 dtex and 10 filaments, a hot water (98°C hot water) dimensional change rate of 8.0% measured by JISL1013, and an irregularity degree of the ultrafine island components of 1.0 and a perfect circle. The obtained islands-in-sea composite fiber was then aligned with a polyester fiber consisting of 33 dtex and 12 filaments (single yarn fineness of 2.75 dtex) and a hot water (98°C hot water) dimensional change rate of 35%. A mixed yarn was then produced.

[0050] Then, the weight is 40g / m 2 A plain knit was produced and scoured. It was then immersed in a 4% by mass NaOH aqueous solution at 80°C for 2 minutes to carry out 20% by mass alkali reduction to remove the sea component, and a fabric was obtained consisting of a mixed yarn of 836 x 10 = 8,360 ultrafine fibers with a diameter of 0.7 μm and 12 normal fineness fibers. The physical properties and quality were measured in the same manner as in the examples. The results are shown in Table 1. The fabric after reduction had tension but was poor in abrasion resistance.

[0051] [Table 1] [Industrial Applicability]

[0052] The present invention makes it possible to provide a fabric that has the soft touch characteristic of ultrafine fibers, and at the same time, has tension, stiffness, and abrasion resistance.

Claims

1. An islands-in-sea type composite fiber in which island components are made of polyethylene terephthalate and a sea component is made of copolymerized polyethylene terephthalate, the diameters of the island components constituting the islands-in-sea type composite fiber being of two or more types, the diameters of the coarse island components being 5 μm to 20 μm, the diameters of the fine island components being 10 to 2000 nm, the fine island components being elongated and flat in the radial direction, and the irregularity degree being 1.2 to 5.0, the number of the fine island components being 25 to 500 times the number of the coarse island components, and the island components accounting for 40% by weight or more.

2. 2. The islands-in-sea type composite fiber according to claim 1, wherein the large-fineness island component is located at the center of one filament of the composite fiber.

3. 3. The islands-in-sea type composite fiber according to claim 1, wherein the finer components are evenly arranged circumferentially around the larger island components.

4. The islands-in-sea type composite fiber according to any one of claims 1 to 3, wherein the number of large-fineness island components in one filament of the islands-in-sea type composite fiber is 3 or less.

5. An islands-in-the-sea type composite fiber according to any one of claims 1 to 4, which is made of multifilaments.

6. A fabric comprising coarse fibers and fine fibers derived from the islands-in-the-sea composite fiber according to any one of claims 1 to 5.

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