Composite fiber, structural yarn, woven knitted fabric and clothing

Abstract

The purpose of the present invention is to provide: a high-sensitivity composite fiber which satisfies both stretching performance and wear resistance, exhibits softness, deep color rendering, and bulkiness that are superior to those of a wool material, and a blended fiber composite fiber, a woven knitted fabric, and a garment comprising the same; this composite fiber contains a polyester-based thermoplastic resin A and a polyester-based thermoplastic resin B, and satisfies the following requirements. (1) The difference (MA-MB) between the weight-average molecular weight MA of the polyester-based thermoplastic resin A and the weight-average molecular weight MB of the polyester-based thermoplastic resin B is 2000-15000. (2) The apparent thickness ratio (Dthick / Dthin) of the composite fiber is from 1.00 to 1.04. And (3) the crimp elongation of the composite fiber is 3.0-25.0%. And (4) in the cross section of the composite fiber, the polyester thermoplastic resin B covers the polyester thermoplastic resin A, and the ratio (tmin / D) of the minimum value tmin of the thickness t of the polyester thermoplastic resin B to the fiber diameter D of the composite fiber is 0.01-0.10. And (5) in the cross section of the composite fiber, the length Ct of the portion where the region having the thickness t satisfying 1.00 tmin < = t < = 1.05 tmin overlaps the circumference of the composite fiber is Ct > = 0.33 C with respect to the circumferential length C of the entire composite fiber.

Description

Technical Field

[0001] The invention relates to composite fibers, structural yarns, woven fabrics and clothing. Background Art

[0002] Conventionally, there has been a demand for wool-like fabrics that have both the softness, deep coloring, and bulkiness that wool materials have, as well as the feel of wool materials, and functions such as stretchability and abrasion resistance, as well as durability.

[0003] Conventionally, as a wool-like fabric, a fabric formed by mixing and interlacing two kinds of latent crimped fibers having different heat shrinkage rates, as disclosed in Patent Document 1, for example, has been proposed.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2004-197231 Summary of the invention

[0007] Problems to be solved by the invention

[0008] As a method for obtaining a wool-like mixed color appearance, there is a method of imparting thickness in the fiber length direction by a stretching ratio less than the natural stretching ratio. This method can obtain a mixed color appearance which is a characteristic of various wool materials. On the other hand, the wool characteristics such as uniform and deep color development, fluffiness, and softness are not sufficient, and the fiber structure of the thick part is not developed, so it is difficult to obtain abrasion resistance.

[0009] In addition, as one of the methods for obtaining a soft and fluffy feel like spun wool, a method of obtaining a fabric by interlacing mixed yarns of long fibers having a crimp structure that can be seen in wool is considered. However, in the technology disclosed in Patent Document 1, when the boiling water shrinkage of the high shrinkage fiber is 10% or more, the fiber is bound in the fabric and sufficient softness cannot be obtained. In addition, the physical properties of the low shrinkage fiber disclosed in Patent Document 1 are significantly reduced by alkali treatment, so there is a problem that durability and feel cannot be achieved at the same time. In other words, it is impossible to simultaneously satisfy the spun wool feel such as softness, deep color development, and fluffiness, stretchability, and wear resistance.

[0010] The present invention has been made in view of the above circumstances, and its object is to provide a highly sensitive, particularly soft wool-like composite fiber, structural yarn, woven knitted fabric and clothing that satisfies both stretch performance and wear resistance, exhibits softness also found in wool materials, has deep color rendering, and has special advantages in fluffiness.

[0011] Means for solving problems

[0012] The present invention has the following configurations.

[0013] [1] A conjugate fiber comprising a polyester thermoplastic resin A and a polyester thermoplastic resin B, wherein the conjugate fiber satisfies the following requirements.

[0014] (1) The weight average molecular weight M of the polyester thermoplastic resin A A The weight average molecular weight M of the polyester thermoplastic resin B is B The difference (M A -M B ) is 2000~15000.

[0015] (2) The apparent thickness ratio (D thick / D thin ) is 1.00~1.04.

[0016] (3) The crimp elongation of the composite fiber is 3.0 to 25.0%.

[0017] (4) In the cross section of the composite fiber, the polyester-based thermoplastic resin B covers the polyester-based thermoplastic resin A, and the minimum value of the thickness t of the polyester-based thermoplastic resin B is t min The ratio of the fiber diameter D of the composite fiber (t min / D) is 0.01~0.10.

[0018] (5) In the cross section of the composite fiber, the thickness t satisfies 1.00t min ≤t≤1.05t min The length C of the portion where the region overlaps with the circumference of the composite fiber t The circumference C of the composite fiber as a whole is C t ≥0.33C.

[0019] [2] The conjugate fiber according to [1] above, wherein at least one other yarn coexists in the form of a mixed conjugate fiber.

[0020] [3] The conjugate fiber according to [2] above, wherein the other yarn is a latent crimped yarn.

[0021] [4] A structured yarn in which cracks are formed all around the surface of the composite fiber described in [1].

[0022] [5] The structural yarn according to [4] above, wherein at least one other yarn is present in the form of a mixed composite fiber.

[0023] [6] The structural yarn according to [5] above, wherein the other yarn is a yarn with crimped shape.

[0024] [7] A woven fabric obtained by weaving at least a part of the composite fiber described in any one of [1] to [3].

[0025] [8] A woven knitted fabric comprising, at least in part, the structural yarn according to any one of [4] to [6].

[0026] [9] Clothing comprising, at least in part, the woven knitted fabric described in [7] or [8] above.

[0027] Effects of the Invention

[0028] According to the present invention, a composite fiber having both stretchability and abrasion resistance and exhibiting softness, deep color development, and high sensitivity of a wool material having advantages in terms of bulkiness, and particularly soft wool-like, can be obtained. In particular, the structured yarn, woven knitted fabric, and clothing using the composite fiber of the present invention can be made into articles in the field of outerwear worn by women and men, such as jackets, suits, and bottoms. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] [ Figure 1 ] Figure 1 This is a cross-sectional view illustrating the existence state of the polyester-based thermoplastic resin A and the polyester-based thermoplastic resin B in the conjugate fiber of the present invention.

[0030] [ Figure 2 ] Figure 2 This is a perspective view illustrating one embodiment of the surface of the conjugate fiber of the present invention.

[0031] [ Figure 3 ] Figure 3 This is a schematic diagram of a stretching and relaxation heat treatment apparatus used when producing the conjugate fiber of the present invention.

[0032] [ Figure 4 ] Figure 4 This is a schematic diagram of a final distribution plate according to Example 1 of the composite fiber of the present invention.

[0033] [ Figure 5 ] Figure 5 This is a schematic diagram of a final distribution plate according to Comparative Example 5 of the composite fiber of the present invention. DETAILED DESCRIPTION

[0034] The conjugate fiber of the present invention comprises a polyester thermoplastic resin A and a polyester thermoplastic resin B, and satisfies the following requirements (1) to (5).

[0035] (1) The weight average molecular weight M of the polyester thermoplastic resin A AThe weight average molecular weight M of the polyester thermoplastic resin B is B The difference (M A -M B ) is 2000~15000.

[0036] (2) The apparent thickness ratio (D thick / D thin ) is 1.00~1.04.

[0037] (3) The crimp elongation of the composite fiber is 3.0 to 25.0%.

[0038] (4) In the cross section of the composite fiber, the polyester-based thermoplastic resin B covers the polyester-based thermoplastic resin A, and the minimum value of the thickness t of the polyester-based thermoplastic resin B is t min The ratio of the fiber diameter D of the composite fiber (t min / D) is 0.01~0.10.

[0039] (5) In the cross section of the composite fiber, the thickness t satisfies 1.00t min ≤t≤1.05t min The length C of the portion where the region overlaps with the circumference of the composite fiber t The circumference C of the composite fiber as a whole is C t ≥0.33C.

[0040] Hereinafter, the present invention will be described in detail, but the present invention is not limited in any way to the scope of the following description unless it exceeds the gist of the present invention.

[0041] [Polyester thermoplastic resin A, polyester thermoplastic resin B]

[0042] The conjugate fiber of the present invention contains a polyester-based thermoplastic resin A and a polyester-based thermoplastic resin B.

[0043] As the polyester resin used in the composite fiber of the present invention, it is preferred that the main repeating unit is a polyethylene terephthalate resin, or the main repeating unit is a polypropylene terephthalate resin, or the main repeating unit is a polybutylene terephthalate resin. It is further preferred that the polyester thermoplastic resin A and the polyester thermoplastic resin B are both mainly repeating units of ethylene terephthalate. Here, "the main repeating unit is ethylene terephthalate" means that the proportion of the structure derived from ethylene terephthalate contained in the repeating unit is 60 mol% or more. The same applies below.

[0044] The above-mentioned polyethylene terephthalate resin, polytrimethylene terephthalate resin, and polybutylene terephthalate resin may have a small amount (usually less than 30 mol%) of copolymer components as required. If the copolymer components of the polyester thermoplastic resin A are 8 mol% or less, the curl elongation can be improved, and the strength is maintained even after alkali reduction, so it is easy to obtain flexibility, which is preferred. Furthermore, by setting the copolymer components to be 8 mol% or less, the molecular orientation in the composite fiber can be maintained even after dyeing, thereby improving the dimensional stability. In addition, it is preferred that the copolymer components of the polyester thermoplastic resin A and the polyester thermoplastic resin B are both 5 mol% or less, and it is further preferred that the polyester thermoplastic resin A and the polyester thermoplastic resin B do not contain copolymer components. By not containing copolymer components, the boiling water shrinkage of the composite fiber can be made less than 10%, thereby making it easy to make the feel of the woven knitted fabric softer.

[0045] It should be noted that, within the scope of not impairing the purpose of the present invention, the polyester thermoplastic resin A and the polyester thermoplastic resin B in the present invention may contain one or more micropore formers, cationic dyeable agents, anti-coloring agents, heat stabilizers, flame retardants, fluorescent whitening agents, matting agents, colorants, antistatic agents, hygroscopic agents, antibacterial agents, inorganic fine particles, etc. as needed.

[0046] In the composite fiber of the present invention, the weight average molecular weight M of the polyester thermoplastic resin A is A The weight average molecular weight M of the polyester thermoplastic resin B B The difference (M A -M B , hereinafter sometimes referred to as "the difference in weight average molecular weight") is 2000 to 15000. If the difference in weight average molecular weight is less than 2000, the resilience and stretchability of the composite fiber will decrease, and cracks caused by alkali treatment will not be formed, so the color development will also decrease. The difference in weight average molecular weight is preferably 5000 or more. On the other hand, if the difference in weight average molecular weight is greater than 15000, the strength of the original fiber decreases and spinning becomes unstable. The difference in weight average molecular weight is preferably 13000 or less.

[0047] In addition, the weight average molecular weight M of the polyester thermoplastic resin A is A The value range is preferably 20000 to 28000, and the weight average molecular weight M of the polyester thermoplastic resin B is B The value range of is preferably 12000 to 20000. When each is within this range, the functionality and durability of the composite fiber are improved, and the process stability when the composite fiber is spun is also good.

[0048] In addition, the weight average molecular weight in the present invention is measured by the method described in the Examples.

[0049] [Composite fiber or structural yarn]

[0050] In the composite fiber of the present invention, the polyester thermoplastic resin B covers the polyester thermoplastic resin A. That is, Figure 1 Schematically, in a cross section of the composite fiber approximately perpendicular to the fiber axis, the polyester thermoplastic resin A1 and the polyester thermoplastic resin B2 exist in a substantially inseparable and bonded state, and the fiber surface has a composite cross section in which the polyester thermoplastic resin B2 covers the polyester thermoplastic resin A1.

[0051] At this time, in the cross section of the composite fiber, the minimum value t16 of the thickness t16 of the polyester thermoplastic resin B covering the polyester thermoplastic resin A is t min The ratio of the fiber diameter D of the composite fiber (t min / D) is 0.01~0.10. If (t min / D) is less than 0.01, the quality of the fabric, abrasion resistance, and color development caused by fuzz, etc. are reduced. It is preferably 0.02 or more. min When (t / D) exceeds 0.10, it is difficult to obtain sufficient curl expression to achieve fluffiness and softness. From the perspective of further improving fluffiness, softness, and stretchability, (t / D) is preferably min / D) is preferably 0.08 or less. min The method of keeping the ratio of carbonyl group A to carbonyl group B in the above range includes, as described later, performing the spinning step using a specific distributor plate.

[0052] Furthermore, the cross section of the composite fiber of the present invention is preferably an eccentric core-sheath type.

[0053] In the cross section of the composite fiber of the present invention, the thickness t satisfies 1.00t min ≤t≤1.05t min The length C of the portion where the region overlaps with the circumference of the composite fiber t The circumference C of the composite fiber as a whole is C t ≥0.33C. Here, the aforementioned thickness t satisfies 1.00t min ≤t≤1.05t min When the region where the conjugate fiber overlaps with the region where the conjugate fiber overlaps is discontinuous, the sum of the values ​​is set to C. t By doing so, the area of ​​the polyester thermoplastic resin A in the cross section (S A ) and the area of ​​the polyester thermoplastic resin B (S BCompared with conventional eccentric core-sheath conjugate fibers having the same ratio, the centers of gravity of the regions where each resin exists are separated, so that the resulting crimped fibers can form finer spirals, can exhibit good crimp, and a woven or knitted fabric excellent in bulkiness and softness can be obtained. Further, in order to obtain crimp suitable for a woven or knitted fabric having bulkiness and softness, it is more preferably set to C t ≥0.40C. In principle, it is C t <C, but preferably C t ≤0.70C. As a method for making C t ≥0.33C, as described later, examples include performing a spinning process using a specific distribution plate, etc.

[0054] Furthermore, the apparent thickness ratio (D thick / D thin ) of the conjugate fiber of the present invention is 1.00 to 1.04. In the present invention, the apparent thickness ratio (D thick / D thin ) means that for a 50 cm conjugate fiber bundle with a load of 0.11 cN / dtex, the width in the direction orthogonal to the fiber axis direction is measured, and after being classified into a relatively thick part and a relatively thin part by the method described in the examples, the average fiber diameter (D thick ) of the relatively thick part and the average fiber diameter (D thin ) of the relatively thin part are in a ratio. The apparent thickness ratio (D thick / D thin ) of the conjugate fiber is theoretically 1.0 or more. On the other hand, if (D thick / D thin ) is greater than 1.04, the abrasion resistance decreases, and the bulkiness and softness also decrease. (D thick / D thin ) is preferably 1.02 or less. (D thick / D thin ) can be set to the above range by performing pin stretching within a range exceeding the natural draw ratio and performing relaxation heat treatment.

[0055] It should be noted that the specific measurement methods for the above-mentioned thickness t, fiber diameter D, thickness ratio, perimeter C, etc. are as described in the examples.

[0056] In addition, the curl elongation of the composite fiber of the present invention is 3.0 to 25.0%. When the curl elongation is lower than 3.0%, bulkiness and abrasion resistance cannot be obtained. The curl elongation is preferably 5.0% or more. On the other hand, when the curl elongation exceeds 25.0%, the curl becomes too fine, thereby impairing the bulkiness and softness of the surface of the woven knitted fabric. In addition, when the curl elongation is too high, the orientation of the thermoplastic resin constituting the composite fiber is high, so cracks are not formed and the color rendering is also poor. The curl elongation is preferably 15.0% or less. The curl elongation can be measured by the method described in the examples.

[0057] The crimp elongation can be set to the above range by performing rod stretching and relaxation heat treatment on the yarn obtained by the spinning process. When only rod stretching is performed, the orientation difference of the thermoplastic resin constituting the composite fiber becomes large, and the crimp elongation becomes too large. On the other hand, when only relaxation heat treatment is performed, the orientation difference of the thermoplastic resin constituting the composite fiber becomes too small, and the crimp elongation becomes too small.

[0058] The present invention satisfies the above requirements (1) to (5) at the same time, thereby solving the problems of conventional mixed fiber materials at one stroke: high wool-like sensitivity such as softness, deep color development, and bulkiness, as well as two characteristics of stretchability and abrasion resistance.

[0059] The cross-sectional shape of the composite fiber is not particularly limited, and may be circular, elliptical, triangular or other cross-sectional shapes. A circular cross-sectional shape is more preferred because composite fibers satisfying requirements (1) to (5) can be stably spun.

[0060] In the composite fiber of the present invention, the area of ​​the polyester thermoplastic resin A in the cross section (S A ) and the area of ​​the polyester thermoplastic resin B (S B ) A :S B When the ratio is preferably 70:30 to 30:70, and more preferably 60:40 to 40:60, the physical properties are improved. A ≥S B .

[0061] The average fiber diameter D of the composite fiber in the present invention is ave The average fiber diameter D is preferably 10 μm to 30 μm. By setting the average fiber diameter within this range, elasticity, stiffness, and stretchability when woven knitted fabrics are obtained, and a soft touch closer to that of natural wool materials can be obtained. ave It is a value calculated from the fineness of the conjugate fiber.

[0062] In addition, the composite fiber of the present invention is preferably twisted according to the desired purpose. The twist coefficient (K) of the twisted yarn is preferably set to 6000 to 24000. By setting it to the above range, it is easier to obtain the stretchability and resilience of the woven knitted fabric. Here, the twist coefficient can be calculated by the following formula.

[0063] Twist coefficient (K) = number of twists (T / m) × √ (fineness (dtex) × 0.9).

[0064] The composite fiber of the present invention usually develops a structure such as crimp through a thermal history. Examples of the thermal history include a hot water treatment and an alkali weight reduction treatment in the dyeing step described below. In the present invention, a composite fiber that develops such a structure such as crimp is referred to as a structured yarn.

[0065] The structural yarn of the present invention preferably has cracks on the surface of the structural yarn in at least a part of the fiber length direction of the fiber. By having cracks on the surface of the structural yarn, the color rendering of the woven knitted fabric can be further improved. Here, the so-called "having cracks on the surface all around" can be formed by one crack on the surface of the structural yarn all around, or by two or more cracks on the surface of the structural yarn all around. In addition, it is preferred that cracks are formed on the surface of the structural yarn all around by 10 or less cracks. It is more preferred to form cracks in a direction substantially perpendicular to the length direction of the structural yarn. It is further preferred that the depth of the cracks in the direction substantially perpendicular to the structural yarn is changed in the direction of the fiber circumference. In addition, the depth of the cracks is preferably 0.5 to 5.0 μm. In addition, as the frequency of crack formation, it is preferred that cracks are formed on the surface of the structural yarn all around by 10 or less cracks within a range of 1 cm in the fiber axis direction. By doing so, the woven knitted fabric using the structural yarn can be made more flexible and have a deeper color rendering.

[0066] Here, the depth of the crack is the depth measured at the deepest part of the crack. In addition, the direction substantially perpendicular to the length direction of the structural yarn refers to, for example, Figure 2 As schematically illustrated, the crack 4 is formed along the circumference substantially perpendicular to the length direction of the structural yarn 3. In the present invention, the depth and length of the crack are observed using an electron microscope, and the average value obtained by measuring 10 cracks in one structural yarn is adopted. The specific measurement method is described in the embodiment. In addition, when it is difficult to continuously observe the entire circumference of the structural yarn, if there are cracks in any part of the multifilament, it can also be regarded as that the cracks cover the entire circumference of the surface.

[0067] [Combined composite fibers, woven fabrics, and clothing containing composite fibers or structural yarns]

[0068] The composite fiber of the present invention may be a composite fiber in which at least one other yarn coexists in the form of a mixed composite fiber. That is, the mixed composite fiber of the present invention is a composite fiber in which at least one other yarn is mixed. By doing so, the wear resistance of the woven knitted fabric can be improved.

[0069] As other yarns, there is no particular limitation as long as they are different from the composite fiber of the present invention, and they are preferably formed of polyester resins from the perspective of having good curling and mechanical properties and excellent dimensional stability to humidity and temperature changes. As polyester resins, polyethylene terephthalate resins whose main repeating units are ethylene terephthalate, polypropylene terephthalate resins whose main repeating units are propylene terephthalate, or polybutylene terephthalate resins whose main repeating units are butylene terephthalate are preferred. It should be noted that the above-mentioned polyethylene terephthalate resin or polybutylene terephthalate resin may have a small amount (usually less than 30 mol% (the total of the acid component and the glycol component is 100 mol%)) of copolymer components as required. In addition, from the perspective of soft hand feel and fiber-to-fiber recycling, it is more preferred that all yarns constituting the mixed fiber composite fiber contain no copolymer components.

[0070] In addition, the boiling water shrinkage of other yarns is preferably 10% or less, particularly preferably 8% or less. If the boiling water shrinkage is 10% or less, the softness of the woven knitted fabric can be further improved. In addition, the boiling water shrinkage is preferably 0% or more. If the boiling water shrinkage is 0% or more, the dimensional stability is excellent. The boiling water shrinkage can be obtained by the dimensions before and after immersion in hot water at 100°C according to JIS L1013 (2021) 8.18.1a method.

[0071] Furthermore, the other yarn is preferably a latent crimped yarn. Here, "latent crimped yarn" means a yarn with a crimp elongation of 5.0% or more. By making the other yarn a latent crimped yarn, stretchability and bulkiness can be improved.

[0072] When the other yarns are latent crimped yarns, the crimp elongation of the other yarns is preferably 10.0 to 30.0% higher than the crimp elongation of the composite fiber. By setting the crimp expression rate to the range, the composite fiber and the crimps with different winding diameters are mixed in the mixed fiber composite fiber, so that the fluffiness and softness closer to spinning can be obtained. When the difference in the curl expression rate is more than 10%, the fluffiness and softness can be further improved. If the difference in the curl expression rate is within 30%, the difference in the winding diameter of the composite fiber becomes smaller, which can prevent the composite fiber from separating from the other yarns.

[0073] In such a mixed fiber composite fiber, the composite fiber in the mixed fiber composite fiber also generally develops a structure such as crimping through a thermal history as described above. Therefore, the structural yarn of the present invention can be a structural yarn in which at least one other yarn coexists in the form of a mixed fiber composite fiber. Moreover, in the mixed fiber composite fiber, when the other yarn coexisting with the composite fiber is a latent crimping fiber, the structure such as crimping is developed through the above-mentioned thermal history, and as a developed crimping fiber, it coexists with the structural yarn in which the structure is developed by the composite fiber.

[0074] The woven knitted fabric of the present invention contains the conjugate fiber and / or mixed conjugate fiber of the present invention in at least a part thereof. The woven knitted fabric may also be composed of only the conjugate fiber or the mixed conjugate fiber.

[0075] That is, the woven knitted fabric of the present invention can be made by weaving and knitting using the composite fiber of the present invention in at least a part. It can be a structural yarn in which the composite fiber in the woven knitted fabric shows a structure through a dyeing process and an alkali reduction process as needed after the aforementioned weaving and knitting, or it can be a woven knitted fabric after the structural yarn showing a structure in advance is made, but the former method is preferred. Such a woven knitted fabric is a woven knitted fabric containing a structural yarn in at least a part. In addition, as described above, the composite fiber or structural yarn provided for the above-mentioned weaving and knitting can be in the form of a composite mixed fiber formed by mixing with other yarns.

[0076] The mixed fiber composite fiber can be a mixed fiber yarn, a composite false twist yarn, or a combined twist yarn of the composite fiber and other yarns. Furthermore, by interweaving or interlacing the mixed fiber composite fiber and other yarns to form a woven knitted fabric, the fluffiness and softness can be further obtained.

[0077] In the woven knitted fabric of the present invention, the ratio of the composite fiber and / or the mixed fiber composite fiber of the present invention to the mass of the woven knitted fabric is preferably 30% by mass or more, more preferably 40% by mass or more. It is also a preferred embodiment that all the fibers constituting the woven knitted fabric are formed of the composite fiber and / or the mixed fiber composite fiber of the present invention.

[0078] The fabric structure of the woven knitted fabric of the present invention is a woven fabric or a knitted fabric. As the woven fabric structure, it can be selected from plain weave, twill weave, satin weave, and their modified structures according to the feel and design. Furthermore, it can also be a multi-layer fabric structure such as a double-layer fabric. As the knitted fabric structure, it can be selected according to the desired feel and design. As for weft knitting, it can be plain knitting, rib knitting, double reverse knitting, tuck knitting, float knitting, lace mesh knitting, and their modified structures, etc., and as for warp knitting, it can be single-bar warp plain knitting, single-bar warp satin knitting, single-bar warp velvet knitting, single-bar warp knitting tuck knitting, double-bar warp plain knitting, warp satin knitting, warp velvet knitting, warp velvet-warp plain knitting, double-bar warp satin knitting, warp oblique plain knitting, and their modified structures, etc. Among these, relatively simple woven knitting structures such as plain weave or its variations, twill weave or its variations, and double bar warp satin weave are more preferred in order to have a fine combed look and a natural appearance with depth.

[0079] In addition, the clothing of the present invention contains the composite fiber (including the structural yarn showing the structure thereof), or the mixed composite fiber, or the woven knitted fabric of the present invention in at least a part. By doing so, it is possible to produce clothing that satisfies the two characteristics of stretch performance and wear resistance of the composite fiber (including the structural yarn showing the structure thereof), or the mixed composite fiber, or the woven knitted fabric of the present invention, and exhibits softness, deep color development, and fluffiness. The clothing of the present invention refers to items in the field of outerwear worn as ladies' and men's clothing, sportswear, and outdoor clothing, especially jackets, suits, bottoms, and parts thereof, such as items including the front body, back body, collar, sleeves, chest pockets, side pockets, underwear, socks, hats, etc.

[0080] [Composite fiber, structured yarn showing structure thereof, mixed fiber composite fiber, and method for producing woven knitted fabric]

[0081] Next, an example of a preferred method for producing the conjugate fiber of the present invention, the structured yarn thereof, the mixed-fiber conjugate fiber, and the woven and knitted fabric will be described.

[0082] The conjugate fiber of the present invention can be produced by the steps of forming the ejected thermoplastic resin into an undrawn yarn or a semi-drawn yarn, winding it, and then drawing it once, and then performing a relaxation heat treatment. In particular, if the conjugate fiber is obtained by the step of forming the semi-drawn yarn, winding it, and then drawing it, it is particularly excellent in stretchability when it is made into a woven knitted fabric and dyed due to the orientation difference between the polyester thermoplastic resin A and the polyester thermoplastic resin B. In addition, the polyester resin A is highly oriented, thereby excellent in resistance to embrittlement due to alkali reduction, which is preferred.

[0083] [Spinning process]

[0084] In the method for producing the composite fiber of the present invention, first, the polyester thermoplastic resin A and the polyester thermoplastic resin B are melted separately, ejected from a spinneret, preferably at a spinning speed of 1400 m / min to 3800 m / min to form an undrawn yarn or a semi-drawn yarn and wound up. In the present invention, it is preferred to set the spinning speed to 2500 to 3800 m / min, form a semi-drawn yarn and wind up.

[0085] It is preferred to prepare the composite fiber from semi-drawn yarns because the wear resistance after alkali weight reduction is excellent. Semi-drawn yarns are more crystallized than undrawn yarns, so local fiber cutting caused by alkali weight reduction can be suppressed.

[0086] The spinning temperature is relative to the melting point (T mA 、T mB ) is preferably +20°C to +50°C. By setting (T mA 、T mB )+20°C or more, thereby preventing the molten polyester thermoplastic resin A and polyester thermoplastic resin B from solidifying and clogging in the spinning machine piping. mA 、T mB )+50°C or less, thereby suppressing thermal degradation of the molten polyester thermoplastic resin A and the molten polyester thermoplastic resin B.

[0087] The spinneret used in the method for producing the conjugate fiber of the present invention may have any known internal structure as long as it can perform spinning with stable quality and operation.

[0088] Here, in the conjugate fiber of the present invention, as described above, in the cross section of the conjugate fiber, the polyester thermoplastic resin A is completely covered with the polyester thermoplastic resin B. By setting such a cross section of the conjugate fiber, it is also possible to suppress the bending of the ejection line caused by the flow rate difference of the two thermoplastic resins ejected from the spinneret, which is a problem in the production of the conjugate fiber.

[0089] The composite fiber of the present invention preferably has a minimum thickness t of the polyester thermoplastic resin B covering the polyester thermoplastic resin A precisely controlled as described above. min , and the thickness t in the cross section of the composite fiber satisfies 1.00t min ≤t≤1.05t min The length C of the portion where the region overlaps with the circumference of the composite fiber t , it is suitable to use a spinning method using a distribution plate as exemplified in Japanese Patent Publication No. 2011-174215, Japanese Patent Publication No. 2011-208313, and Japanese Patent Publication No. 2012-136804. By using such a distribution plate, t minIf the above range is set, the min The polyester thermoplastic resin A is exposed as a result of becoming too small, thereby suppressing the whitening phenomenon and fuzz of the woven and knitted fabric. min Even if the curvature of the composite fiber is too large, the curl of the composite fiber can be expressed within an appropriate range, thereby improving the stretchability of the woven knitted fabric. In the method using such a distribution plate, the cross-sectional shape of the monofilament can be controlled by arranging the distribution holes provided in the final distribution plate at the most downstream among the distribution plates composed of multiple sheets.

[0090] [Stretching and relaxation heat treatment process]

[0091] Next, the yarn produced through the spinning step is stretched at a ratio exceeding the natural stretch ratio of the yarn, using Figure 3 The stretching and relaxation heat treatment apparatus is used to perform the stretching process, and then the relaxation heat treatment is performed to form the relaxation heat treated yarn. Through this process, the desired composite fiber can be obtained.

[0092] Figure 3 This is a schematic diagram of a stretching and relaxation heat treatment apparatus used in manufacturing the composite fiber of the present invention. That is, after the semi-stretched yarn 5 passes through the guide 6, it is heated and stretched by the heat rod 8 between the first supply roller 7 and the second supply roller 9, and then the relaxation heat treatment is performed by the heater 10 between the second supply roller 9 and the third supply roller 11 to form a composite fiber 12, which is wound in the winding section 13.

[0093] For example, a semi-drawn yarn obtained by composite spinning at a spinning speed of 2500 to 3800 m / min is subjected to rod drawing at a draw ratio of 1.5 to 2.2 times, a hot rod temperature of 70 to 150° C., and a yarn speed of 200 to 800 m / min, and then subjected to a relaxation heat treatment at a heater temperature of 130 to 180° C. and an overfeed ratio of +25 to 55% (as an example, a semi-drawn yarn obtained by composite spinning at a spinning speed of 2600 m / min is subjected to rod drawing at a draw ratio of 1.8 times, a hot rod temperature of 95° C., and a yarn speed of 300 m / min, and then subjected to a relaxation heat treatment at a heater temperature of 140° C. and an overfeed ratio of +10%), thereby obtaining a composite fiber having an apparent thickness ratio of 1.00 to 1.04 and a crimp elongation of 3.0 to 25.0%. In addition, it is preferred that the stretching is performed in a region above the upper limit of the natural stretch ratio, and the overfeed ratio of the relaxation heat treatment is 50% or less of the stretch ratio. By stretching within the above range, it is easy to control the weight loss of the fiber due to the alkali treatment, and it is possible to achieve both flexibility and abrasion resistance.

[0094] In addition, the drawn composite fiber can be combined with other yarns before or after winding to form a composite composite fiber. The composite method is not particularly limited, and common methods such as interlaced composite and taslan composite can be used.

[0095] [Woven knitted fabric forming process]

[0096] The composite fiber obtained in the stretching step is made into a woven fabric or a knitted fabric. In the case of a woven fabric, it is woven using an air jet loom, a water jet loom, a rapier loom, a projectile loom, a shuttle loom, or the like. In the case of a knitted fabric, it is knitted using a weft knitting machine such as a flat knitting machine, a fully fashioned flat knitting machine, a circular knitting machine, a computerized jacquard knitting machine, a sock knitting machine, a circular knitting machine, a tricot knitting machine, a raschel warp knitting machine, an air jet loom, or a Milanese knitting machine.

[0097] [Alkali reduction process]

[0098] Furthermore, the woven knitted fabric obtained in the step of forming the woven knitted fabric is subjected to an alkali reduction treatment as required so that the alkali reduction rate becomes 5 to 20%, more preferably 10 to 15%. This step can achieve a state where cracks are present on the entire surface of the composite fiber. In order to avoid embrittlement due to selective reduction, a continuous reduction process is preferred.

[0099] [Dyeing process]

[0100] Furthermore, as required, conventional refining, relaxation treatment, intermediate heat setting, dyeing processing, and final heat setting (in the present invention, these processes are sometimes collectively referred to as "dyeing process") can be carried out before and / or after the above-mentioned alkali reduction process, or at the same time. In order to obtain the fluffiness and softness of the present invention, the feeding and tension management of each process are appropriately performed. For example, it is ideal that in the axial direction of the composite fiber of the present invention, in a roll-to-roll device that can control the feeding amount, the liquid amount and flow rate are controlled so that the overfeed is within 10%, and in an intermittent liquid flow dyeing machine, the liquid amount and flow rate are controlled so that excessive tension is not applied in the traveling direction. Although dyeing depends on the dyeability of the thermoplastic resin constituting the composite fiber or other composite yarns, it is carried out using disperse dyes or cationic dyes in a dyeing solution preferably at 110 to 130°C.

[0101] The composite fiber of the present invention usually develops a structure and crimps through the heat history in the dyeing step or the alkali weight reduction step. In addition, cracks are formed on the surface of the composite fiber in the alkali weight reduction step.

[0102] Example

[0103] Next, the present invention will be specifically described based on examples. However, the present invention is not limited to these examples. It should be noted that in the measurement of various physical properties, the measurement was performed based on the above-mentioned method unless otherwise specified.

[0104] [Measurement method]

[0105] (1) Determination of weight average molecular weight of thermoplastic resin

[0106] The weight average molecular weight of the polyester thermoplastic resin A and the polyester thermoplastic resin B used in the conjugate fiber was measured using "TOSO GMHHR-H(S)HT" manufactured by Tosoh Corporation as a gel permeation chromatography (GPC) testing machine.

[0107] Detector: Differential refractive index detector RI (Waters-2414, sensitivity 128x)

[0108] Column: Shodex HFIP806M manufactured by Showa Denko K.K. (2 connected)

[0109] Solvent: Tetrahydrofuran (25 cm 3 )

[0110] Flow rate: 1.0mL / min

[0111] Column temperature: 30°C

[0112] Injection volume: 0.10mL

[0113] Standard material: polystyrene.

[0114] (2) Average fiber diameter D ave Determination of

[0115] The fineness and number of filaments of the composite fiber were measured according to JIS L1013 (2010) 8.3.1B method and JIS L1013 (2010) 8.4, respectively, and the single-filament fineness was obtained by fineness / number of filaments. The average fiber diameter was calculated from the obtained single-filament fineness according to the following formula.

[0116] [Mathematical formula 1]

[0117]

[0118] ρ: Density (g / m 3 ) In the case of polyethylene terephthalate, it is 1.38×10 6 g / m 3 .

[0119] (3) Measurement of fiber diameter D, thickness t of polyester thermoplastic resin B covering polyester thermoplastic resin A, and fiber circumference C

[0120] The multifilament formed by the composite fiber is embedded with an embedding agent such as epoxy resin at 10 locations in a row at intervals of 1 cm in the fiber axis direction, and the resulting substance is used as a sample. The image of each sample is taken with a transmission electron microscope (TEM) at a magnification that can observe more than 10 fibers. At this time, metal staining is implemented to clarify the contrast of the joint between the polyester thermoplastic resin A and the polyester thermoplastic resin B. As an image analysis software, "WinROOF2015" manufactured by Mitani Shoji Co., Ltd. is used to measure the fiber diameter D, each circumference C measured therefrom, the thickness t of the polyester thermoplastic resin B, and the area Sa of the polyester thermoplastic resin A in the cross section from all the single fibers in the observed image. The fiber diameter D adopts the circle conversion diameter. The obtained fiber diameter D, circumference C, thickness t, and area ratio SA of the polyester thermoplastic resin A are prepared for 10 points and averaged. The fiber diameter D was calculated to three significant figures, and the circumference C, thickness t, and area ratio Sa were calculated to two significant figures as the fiber diameter D, circumference C, thickness t, and area ratio Sa of the present invention. In addition, as for the thickness t, 360 locations were measured every 1° in the circumferential direction of the fiber, and the smallest value was taken as t min , set the thickness t to 1.00t min ≤t≤1.05t min The length of the portion where the region overlaps with the circumference of the composite fiber is defined as C t In addition, the area ratio Sa of the polyester-based thermoplastic resin A is subtracted from the total area S of the cross section to obtain the area ratio Sb of the polyester-based thermoplastic resin B.

[0121] (4) Curl elongation

[0122] The crimp elongation of the conjugate fiber was calculated by the following formula.

[0123] Curl elongation (%) = [(L1-L0) / L0] × 100

[0124] L0: 50 cm of composite fiber was wrapped in gauze in a free state and left for 24 hours, then treated with hot water at 100°C for 15 minutes without load, and dried at 20°C for 24 hours at 65 RH%, and then hung at 1.1 × 10 -3 cN / dtex load after 30 seconds

[0125] L1: The length after 30 seconds when a load of 0.22 cN / dtex is applied after L0 measurement.

[0126] The measurement was performed 10 times, and the average value was rounded off to the second decimal place and the value was calculated using the first decimal place. In the case of mixed composite fibers, the composite fibers were separated and measured before L0 measurement.

[0127] (5) Apparent thickness ratio (D thick / D thin )

[0128] The composite fiber was fixed at both ends while a load of 0.11 cN / dtex was applied to the composite fiber. The diameter of the fiber bundle was measured at 500 locations at intervals of 1.0 mm in the fiber axis direction using an image obtained by taking a photo of the side of the fixed sample at a magnification of 200 times using a digital microscope "VHX2000" manufactured by KEYENCE CORPORATION. thick ) and the fiber diameter of the detail (D thin ) is determined by defining the thinner portion than the average value of all the measured data as the thin portion (thin portion < average value), and defining the thicker portion than the average value of all the measured data as the thick portion (thick portion > average value), finding the average value of the thick portion and the thin portion, and calculating the apparent thickness ratio. For the apparent thickness ratio, the third decimal place is rounded off and the value is calculated with two decimal places.

[0129] In addition, the apparent thickness ratio of the structural yarn obtained by extracting the structural yarn from the woven knitted fabric after the dyeing step (final heat setting) was also determined by the same method.

[0130] (6) Determination of the presence and depth of cracks

[0131] Using a scanning electron microscope "S-3400N" manufactured by Hitachi, Ltd. as an electron microscope, an arbitrary part of the structural yarn was observed from the woven knitted fabric after dyeing. The composite fiber was extracted from the woven knitted fabric after final heat setting without applying external force, and the presence or absence of cracks and the crack morphology were confirmed. If cracks were present, the side surface in the direction substantially orthogonal to the crack was observed at a magnification of 2000 times. The deepest depth and length of the crack were measured, and the average value of 10 cracks measured in one composite fiber was taken as the crack depth.

[0132] It should be noted that the crack morphology was determined based on the following criteria.

[0133] A. This is a form in which cracks are formed on the entire circumference of the surface of the structural yarn by 10 or less cracks within a range of 1 cm in the fiber axis direction.

[0134] B. There are less than 10 cracks on the surface of the structural yarn.

[0135] C. Although cracks are formed, the degree is intermediate between B and C.

[0136] D. Although cracks were formed, they were only within half the circumference of the surface of the structural yarn.

[0137] E. is an intermediate level between D and F.

[0138] F. No cracks were formed.

[0139] (7) Stretchability of woven and knitted fabrics

[0140] The elongation in the direction of the conjugate fiber of the present invention is measured according to JIS L1096 (2010) 8.16.1B method. When the conjugate fiber of the present invention is used in both the warp and weft, the elongation of each of the warp and weft is measured and the average value is used as the result.

[0141] (8) Wear resistance

[0142] The woven knitted fabric was dyed black, cut into a circle with a diameter of 10 cm, moistened with distilled water and mounted on a disk. The woven knitted fabric cut into a 30 cm square was directly fixed on a horizontal plate in a dry state. The disk with the woven knitted fabric moistened with distilled water was brought into horizontal contact with the woven fabric fixed on the horizontal plate, and the disk was moved in a circular motion at a speed of 50 rpm for 10 minutes in a manner such that a circle with a diameter of 10 cm was drawn at the center of the disk, so that two woven knitted fabrics were rubbed. After the friction was completed and left for 4 hours, the degree of discoloration of the woven knitted fabric mounted on the disk was judged on a scale of 1 to 5 using a gray scale for discoloration and 0.5 levels.

[0143] (9) Evaluation of color development, bulkiness, and softness of woven and knitted fabrics using composite fibers and mixed composite fibers

[0144] For samples of woven knitted fabrics formed using the composite fiber of the present invention, 10 healthy adults (5 males and 5 females) were used as evaluators, and the color development of the woven knitted fabrics was visually evaluated, and the bulkiness and softness were evaluated by touch, and sensory evaluation was performed with 5 levels of very good (5 points), good (4 points), ordinary (3 points), not very good (2 points), and poor (1 point). The average value of each examiner was rounded off to the second decimal place and calculated to the first decimal place. It should be noted that, for comparison, a woven fabric formed of false twisted yarn of polyethylene terephthalate having the same total fineness and the same number of filaments as in the examples and comparative examples was set to ordinary (3 points).

[0145] [Example 1]

[0146] The polyester thermoplastic resin A is polyethylene terephthalate with a weight average molecular weight of 25,000, and the polyester thermoplastic resin B is polyethylene terephthalate with a weight average molecular weight of 15,000. The spinning temperature is 290° C., and the polyester thermoplastic resin A and the polyester thermoplastic resin B have a mass composite ratio of 50:50. The distribution holes in the final distribution plate disposed at the most downstream of the distribution plates composed of a plurality of sheets are arranged as follows: Figure 4 In the form shown, the fiber flows into a composite fiber spinneret having 12 ejection holes. Figure 4 , a situation in which a group of distribution holes 15 of the polyester thermoplastic resin B is arranged around a group of distribution holes 14 of the polyester thermoplastic resin A in the final distribution plate is shown. In this way, an eccentric core-sheath type ( Figure 1 The yarn ejected from the spinneret was cooled by an air cooling device and given an oil agent, and then wound up at a speed of 2600 m / min using a winding machine, and stably wound up as a semi-drawn yarn with a total fineness of 100 dtex and a single filament number of 12 filaments.

[0147] Next, the semi-drawn yarn was fed to a drawing device at a speed of 300 m / min. Figure 3 The stretching apparatus shown in the figure was used to stretch the steel sheet at a stretching ratio of 1.80 times and a hot rod temperature of 95°C, and then a relaxation heat treatment was performed at a heater temperature of 140°C and an overfeed ratio of +20%, thereby obtaining an apparent thickness ratio (D thick / D thin ) 1.02 composite fiber. Regarding the composite fiber, the aforementioned (t min / D) is 0.020, C t The relationship with C is C t =0.40C(C t / C=0.40). In addition, S A :S B =50:50.

[0148] Next, the conjugate fiber having a twist of 1200 T / m was used as warp and weft to produce a 3 / 1 twill woven fabric with a warp density of 115 yarns / 2.54 cm and a weft density of 105 yarns / 2.54 cm.

[0149] The woven fabric was then subjected to scouring, relaxation, and intermediate heat setting. Thereafter, as a dyeing step, the disperse dye "Dystar Navy Blue S-GL" was used at a concentration of 1.0 owf% at 130°C for 30 minutes, and a final heat setting was performed at 160°C. The results are shown in Table 1.

[0150] [Example 2]

[0151] In the dyeing process, a conjugate fiber and a woven fabric were obtained in the same manner as in Example 1 except that an alkali reduction process (reduction rate: 10%) was performed after intermediate setting to form cracks on the surface of the single yarn of the conjugate fiber.

[0152] [Example 3]

[0153] In the composite fiber prepared in Example 1, polyethylene terephthalate fiber (56dtex-24f, boiling water shrinkage of 8%, crimping elongation of 0.0%) as other yarns was interwoven and mixed by an interweaving nozzle to prepare a composite fiber with a mixing ratio of 54%, and the warp density was 88 strands / inch (inch) and the weft density was 79 strands / inch (2.54cm). A woven fabric was obtained in the same manner as in Example 2. The results are shown in Table 1. Here, the boiling water shrinkage is determined by measuring the dimensional change before and after immersion in hot water at 100°C according to JIS L1013 (2021) 8.18.1a method.

[0154] [Example 4]

[0155] The results are shown in Table 1.

[0156] Stretched yarn: A polyethylene terephthalate with a weight average molecular weight of 25,000 and a polyethylene terephthalate with a weight average molecular weight of 15,000 were fed into a spinneret for parallel type composite fibers having 12 ejection holes at a spinning temperature of 290°C so as to have a mass conjugation ratio of 50:50 for each polyethylene terephthalate. The yarn ejected from the spinneret was cooled by an air cooling device and provided with an oil agent, and then pulled at 1,500 m / min, stretched 2.67 times between a preheating roll at 80°C and a roll at 4,000 m / min, heat-set at 130°C, and wound up by a winder to be stably wound up as a stretched yarn having a total fineness of 56 dtex, a single filament number of 12 filaments, and a crimp elongation of 32.0%.

[0157] [Example 5]

[0158] The results are shown in Table 1, except that the polyester thermoplastic resin A was a polyester having a weight average molecular weight of 19,000 and the polyester thermoplastic resin B was a polyester having a weight average molecular weight of 15,000, a woven fabric was obtained in the same manner as in Example 2.

[0159] [Example 6]

[0160] The woven fabric was obtained in the same manner as in Example 2 except that the polyester thermoplastic resin A was a polyester having a weight average molecular weight of 25,000 obtained by copolymerizing isophthalic acid (IPA) in an amount of 10 mol % relative to the acid component.

[0161] [Example 7]

[0162] The results are shown in Table 1, except that the heat setting temperature of the other yarns was 125°C and the boiling water shrinkage was 10%.

[0163] [Example 8]

[0164] The results are shown in Table 1.

[0165] Stretched yarn: Polyethylene terephthalate with a weight average molecular weight of 25,000 and polyethylene terephthalate with a weight average molecular weight of 15,000, which were obtained by copolymerizing isophthalic acid (IPA) at 10 mol% relative to the acid component, were flowed into a spinneret for parallel-type composite fibers having 12 ejection holes at a spinning temperature of 290°C and a mass conjugation ratio of 50:50 for each polyethylene terephthalate. The yarn ejected from the spinneret was cooled by an air cooling device, and after being provided with an oil agent, it was pulled at 1,500 m / min, stretched 2.67 times as it was between a preheating roll at 80°C and a roll at 4,000 m / min, heat-set at 130°C, and wound up by a winder to be stably wound up as a stretched yarn having a total fineness of 56 dtex and a single filament number of 12 filaments.

[0166] [Comparative Example 1]

[0167] In Example 4, the spinneret used was replaced with a spinneret of the type described in Japanese Patent Application Laid-Open No. 09-157941 from a distribution plate type spinneret to produce a parallel type composite fiber composed of polyester thermoplastic resin A and polyester thermoplastic resin B. A woven fabric was obtained in the same manner as in Example 4. The obtained woven fabric had low wear resistance, and high molecular weight polyethylene terephthalate with low color development was exposed, resulting in poor color development. The results are shown in Table 2.

[0168] [Comparative Example 2]

[0169] A woven fabric was obtained in the same manner as in Example 4 except that the rod stretching was not performed but the relaxation heat treatment was performed. The obtained woven fabric had low abrasion resistance due to partial fiber cutting caused by the alkali treatment, and the crimp elongation of the conjugate fiber was low, so the bulkiness was also poor. The results are shown in Table 2.

[0170] [Comparative Example 3]

[0171] A woven fabric was obtained in the same manner as in Example 4 except that the rod stretching was performed and the relaxation heat treatment was not performed. The obtained woven fabric had low color development due to high orientation of the conjugate fibers, and also had poor bulkiness and softness due to excessively high crimp elongation. The results are shown in Table 2.

[0172] [Comparative Example 4]

[0173] A woven fabric was obtained in the same manner as in Example 4 except that the rod stretching ratio was 1.50 times, the heat treatment overfeed ratio was 0%, and the apparent thickness ratio was 1.22 and the crimp elongation was 27.0%. The obtained woven fabric had low abrasion resistance in the thick part and high crimp elongation, and therefore poor softness. The results are shown in Table 2.

[0174] [Comparative Example 5]

[0175] A woven fabric was obtained in the same manner as in Example 4 except that the rod stretching ratio was set to 1.50 times to obtain a composite fiber having an apparent thickness ratio of 1.22. The obtained woven fabric had low abrasion resistance and low crimp elongation in the thick part, and therefore poor bulkiness and softness. The results are shown in Table 2.

[0176] [Comparative Example 6]

[0177] In Example 4, the minimum value t of the thickness t of the polyester thermoplastic resin B covering the polyester thermoplastic resin A is set to min The value is 10 times, and the configuration of the distribution holes of the final distribution plate of the spinneret to be used is Figure 4 Change to Figure 5 , a polyester thermoplastic resin A and a polyester thermoplastic resin B are formed, and (t min The results are shown in Table 2.

[0178] [Comparative Example 7]

[0179] The results are shown in Table 2, except that the polyester thermoplastic resin A was polyethylene terephthalate having a weight average molecular weight of 20,000 and the polyester thermoplastic resin B was polyethylene terephthalate having a weight average molecular weight of 19,000, a woven fabric was obtained in the same manner as in Example 2.

[0180] [Table 1]

[0181]

[0182] [Table 2]

[0183]

[0184] Description of Reference Numerals

[0185] 1: Polyester thermoplastic resin A

[0186] 2: Polyester thermoplastic resin B

[0187] 3: Composite fiber

[0188] 4: Crack

[0189] 5: Semi-stretched yarn

[0190] 6: Guide

[0191] 7: 1st supply roller

[0192] 8: Hot Rod

[0193] 9: Second supply roller

[0194] 10: Heater

[0195] 11: 3rd supply roller

[0196] 12: Composite fiber

[0197] 13: Winding section

[0198] 14: Distribution hole of polyester thermoplastic resin A

[0199] 15: Distribution hole of polyester thermoplastic resin B

[0200] 16: Thickness t of polyester thermoplastic resin B covering polyester thermoplastic resin A

Claims

1. A composite fiber comprising a polyester thermoplastic resin A and a polyester thermoplastic resin B, wherein the composite fiber satisfies the following requirements: (1) The weight average molecular weight M of the polyester thermoplastic resin A A The weight average molecular weight M of the polyester thermoplastic resin B B The difference (M A -M B ) is 2000~15000, (2) The apparent thickness ratio (D thick / D thin ) is 1.00~1.04, (3) The crimp elongation of the composite fiber is 3.0 to 25.0%, (4) In the cross section of the composite fiber, the polyester-based thermoplastic resin B covers the polyester-based thermoplastic resin A, and the minimum value of the thickness t of the polyester-based thermoplastic resin B is t min The ratio of the fiber diameter D of the composite fiber (t min / D) is 0.01~0.10, (5) In the cross section of the composite fiber, the thickness t satisfies 1.00t min ≤t≤1.05t min The length C of the portion where the area overlaps with the circumference of the composite fiber t The circumference C of the composite fiber as a whole is C t ≥0.33C.

2. The composite fiber according to claim 1, wherein At least one other yarn coexists in the form of a mixed composite fiber.

3. The composite fiber according to claim 2, wherein The other yarns are latent crimped yarns.

4. A structural yarn, wherein cracks are formed all around the surface of the composite fiber according to claim 1.

5. The structural yarn according to claim 4, wherein: At least one other yarn coexists in the form of mixed composite fibers.

6. The structural yarn according to claim 5, wherein: The other yarns are yarns with visible curls.

7. A woven fabric obtained by woven knitting at least partly using the conjugate fiber according to any one of claims 1 to 3.

8. A woven knitted fabric comprising the structural yarn according to any one of claims 4 to 6 in at least a part thereof.

9. A garment comprising the woven knitted fabric according to claim 7 or 8 in at least a part thereof.

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