Composite fiber and composite mixed fiber, woven knitted fabric and clothing containing the same

Abstract

In order to provide a composite fiber that satisfies both tensile properties and abrasion resistance and exhibits a fine worsted-spun appearance closer to wool, a deep, natural appearance, and a high sense of touch, and a woven and knitted fabric and clothing containing the same, a polyester thermoplastic resin A and a polyester thermoplastic resin B are included and the following requirements (1) to (4) are satisfied: (1) 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 ) is 2000 to 15000. (2) In the composite fiber, the apparent thickness ratio (D thick / D thin ) is 1.05 to 3.00. (3) 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 thermoplastic resin B is t min The ratio of the fiber diameter D of the composite fiber (t min / D) is 0.01 to 0.10. (4) In the cross section of the composite fiber, the thickness t satisfies 1.00t min ≤t≤1.05t min The perimeter of the part C t The circumference C of the composite fiber as a whole is C t ≥0.33C.

Description

Technical Field

[0001] The present invention relates to a composite fiber, a woven knitted fabric, and clothing containing the same, and particularly relates to a composite fiber having high sensibility such as a fine worsted-spinning appearance and a deep, natural appearance, and functional properties such as stretchability, a composite mixed fiber, a woven knitted fabric, and clothing containing the same. Background Art

[0002] There has long been a demand for worsted-like fabrics that reproduce the soft, fluffy feel of wool and the high resilience of stretch and stiffness. In recent years, in particular, there has been a demand for fabrics that minimize the wearer's feeling of restraint when used in clothing and that provide better movement. In other words, there has been a demand for fabrics that have a worsted-like appearance comparable to wool while also exhibiting excellent stretchability.

[0003] Furthermore, woven and knitted fabrics made of natural fibers such as wool generate a significant amount of fiber waste during use and washing. In particular, fiber waste shed from the fibers during washing can cause various problems, including increased waste, increased wastewater treatment load, and increased maintenance burden on washing machines.

[0004] Conventionally, as worsted-like fabrics, there has been proposed, for example, worsted-like fabrics comprising composite fibers having a scale structure (scale) formed on the fiber surface of wool and subjected to fine and fine detail patterning, as disclosed in Patent Document 1.

[0005] On the other hand, as a fiber used for a fabric having stretchability, an eccentric core-sheath composite fiber as disclosed in Patent Document 2 is known.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2003-328248

[0009] Patent Document 2: International Publication No. 2018 / 110523. Summary of the Invention

[0010] Problems to be solved by the invention

[0011] One approach to suppressing fiber shedding is to use long fibers to produce a worsted-like fabric. However, in the technique disclosed in Patent Document 1, when the composite fibers are parallel, friction and impact can cause delamination at the interface, leading to deterioration in fabric quality due to streaking and fuzzing. Furthermore, because cracks during alkali treatment only penetrate one side of the surface, there is the issue of insufficiently achieving a fine, worsted-like appearance. Patent Document 1 also describes composite fibers using the conventional eccentric core-sheath type. However, because the low-shrinkage component covers the high-shrinkage component, sufficient tensile properties cannot be achieved compared to parallel types. In other words, stretchability, abrasion resistance, and a worsted-like appearance cannot be simultaneously achieved.

[0012] Patent Document 2 discloses an invention for a fabric with a uniform and smooth appearance, completely contrary to the variegated appearance and worsted-spun texture. Therefore, it is impossible to achieve the variegated appearance of natural wool. Furthermore, a method of blending fibers with different dyeing properties is also disclosed as a means of achieving variegated appearance. However, this method results in significant variations in the pitch of the variegated colors due to twisting.

[0013] The present invention has been completed in view of the above situation, and its purpose is to provide a composite fiber that satisfies both tensile properties and abrasion resistance, presents a fine worsted-spun appearance closer to wool, has a deep natural appearance and high sensibility, and a composite mixed fiber, woven knitted fabric and clothing containing the same.

[0014] Means for solving problems

[0015] The conjugated fiber of the present invention comprises a polyester thermoplastic resin A and a polyester thermoplastic resin B, and the conjugated fiber satisfies the following requirements (1) to (4):

[0016] (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;

[0017] (2) In the composite fiber, the apparent thickness ratio (D thick / D thin ) is 1.05~3.00;

[0018] (3) In the cross section of the composite fiber, the polyester thermoplastic resin B covers the polyester thermoplastic resin A, and the minimum value t of the thickness t of the polyester thermoplastic resin B is t min The ratio of the fiber diameter D of the composite fiber (t min / D) is 0.01 to 0.10;

[0019] (4) In the cross section of the composite fiber, the thickness t satisfies 1.00t min ≤t≤1.05t min The perimeter of the part C t The circumference C of the composite fiber as a whole is C t ≥0.33C.

[0020] According to a preferred embodiment of the conjugate fiber of the present invention, the hysteresis loss rate of the conjugate fiber during elongation recovery under a maximum load of 0.5 cN / dtex is 0 to 70%.

[0021] According to a preferred embodiment of the composite fiber of the present invention, the thickness-to-length ratio LR1 (L2 / L1) of the thin part length (L2) to the thick part length (L1) in the fiber axis direction under a measuring load of 0.00166 cN / dtex of the composite fiber is 0.90 to 1.40, and the ratio of the thickness-to-length ratio LR2 at a measuring load of 0.11 cN / dtex to the thickness-to-length ratio LR1 at a measuring load of 0.00166 cN / dtex (LR2 / LR1) is 1.20 to 2.10.

[0022] According to a preferred embodiment of the composite fiber of the present invention, at least the fiber diameter (D thick ) portion, there are cracks on the surface of the composite fiber.

[0023] In addition, the mixed fiber of the present invention is obtained by combining at least one other yarn with the composite fiber of the present invention.

[0024] Furthermore, the woven knitted fabric of the present invention contains the above-mentioned conjugate fiber or the above-mentioned conjugate mixed fiber in at least a part thereof.

[0025] Furthermore, the clothing of the present invention contains the composite fiber or the composite mixed fiber, or the woven knitted fabric in at least a part.

[0026] Effects of the Invention

[0027] According to the present invention, a composite fiber having high resilience, such as elasticity and stiffness, and a soft, bulky feel can be obtained. In particular, the composite fiber of the present invention can be made into composite mixed fibers, woven and knitted fabrics, and outerwear items for women and men, such as jackets, suits, and bottoms, exhibiting excellent tensile properties and abrasion resistance, a fine worsted-spun texture closer to natural wool, and a deep, natural appearance with a high sense of touch. These fibers can also be used as outerwear for women and men, such as jackets, suits, and bottoms. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] [ Figure 1 ] Figure 1This is a cross-sectional view illustrating the existence forms of the polyester-based thermoplastic resin A and the polyester-based thermoplastic resin B in the conjugated fiber of the present invention.

[0029] [ Figure 2 ] Figure 2 This is a perspective view illustrating one embodiment of the surface of the conjugate fiber of the present invention.

[0030] [ Figure 3 ] Figure 3 This is a schematic diagram of a drawing apparatus used when producing the conjugate fiber of the present invention.

[0031] [ 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.

[0032] [ Figure 5 ] Figure 5 This is a schematic diagram of a final distribution plate according to Comparative Example 3 of the composite fiber of the present invention. DETAILED DESCRIPTION

[0033] The conjugate fiber of the present invention comprises a polyester thermoplastic resin A and a polyester thermoplastic resin B, and the conjugate fiber satisfies the following requirements (1) to (4):

[0034] (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;

[0035] (2) In the composite fiber, the apparent thickness ratio (D thick / D thin ) is 1.05~3.00;

[0036] (3) In the cross section of the composite fiber, the polyester thermoplastic resin B covers the polyester thermoplastic resin A, and the minimum value t of the thickness t of the polyester thermoplastic resin B is t min The ratio of the fiber diameter D of the composite fiber (t min / D) is 0.01 to 0.10;

[0037] (4) In the cross section of the composite fiber, the thickness t satisfies 1.00t min ≤t≤1.05t min The perimeter of the part C t The circumference C of the composite fiber as a whole is C t ≥0.33C.

[0038] Hereinafter, the present invention will be described in detail. However, 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.

[0039] [Polyester thermoplastic resin A, polyester thermoplastic resin B]

[0040] The conjugate fiber of the present invention contains a polyester-based thermoplastic resin A and a polyester-based thermoplastic resin B.

[0041] Specific examples of the polyester resin used in the conjugated fiber of the present invention include preferably polyethylene terephthalate resins whose main repeating units are ethylene terephthalate, polypropylene terephthalate resins whose main repeating units are trimethylene terephthalate, or polybutylene terephthalate resins whose main repeating units are butylene terephthalate. It is further preferred that both the polyester thermoplastic resin A and the polyester thermoplastic resin B have ethylene terephthalate as their main repeating units.

[0042] The above-mentioned polyethylene terephthalate resin, polypropylene terephthalate resin, and polybutylene terephthalate resin may contain a small amount (usually less than 30 mol%) of copolymer components as needed. When the copolymer component of the polyester thermoplastic resin A is 8 mol% or less, it is easy to make the hysteresis loss less than 70%, which is preferred. Furthermore, by making the copolymer component less than 8 mol%, it is possible to maintain the molecular orientation in the composite fiber 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 less than 5 mol%, and it is further preferred that the polyester thermoplastic resin A and the polyester thermoplastic resin B do not contain copolymer components.

[0043] It should be noted that the polyester thermoplastic resin A and the polyester thermoplastic resin B in the present invention may contain one or more micropore formers, cationic dyeing 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 within the scope not impairing the purpose of the present invention.

[0044] 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 BThe difference in weight-average molecular weight (hereinafter sometimes referred to as "weight-average molecular weight difference") is 2,000 to 15,000. By setting the weight-average molecular weight difference to 2,000 or more, preferably 5,000 or more, a composite fiber with high resilience and excellent stretchability can be obtained. On the other hand, by setting the weight-average molecular weight difference to 15,000 or less, preferably 13,000 or less, the strength of the precursor fiber can be increased, and stable spinning can be achieved.

[0045] In addition, the weight average molecular weight M of the polyester thermoplastic resin A is A The range of the value 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 it is within this range, the functionality and durability of the conjugate fiber are improved, and the process stability when the conjugate fiber is spun is also good.

[0046] It should be noted that the weight average molecular weight in the present invention is prepared by completely dissolving 2.0 mg of the composite fiber in 2.5 cm of tetrahydrofuran. 3 The weight average molecular weight is a value obtained by performing a gel permeation chromatography test using polystyrene as a standard substance using a measurement solution prepared by gel permeation chromatography. The weight average molecular weight is expressed as an integer. For example, a gel permeation chromatography (GPC) tester can be used, for example, the "TOSO GMHHR-H(S)HT" manufactured by Tosoh Corporation.

[0047] [Composite Fiber]

[0048] In the composite fiber of the present invention, the polyester thermoplastic resin B covers the polyester thermoplastic resin A. That is, Figure 1 As schematically illustrated, in a cross section approximately perpendicular to the fiber axis of the conjugated fiber, the polyester thermoplastic resin A and the polyester thermoplastic resin B are present in a substantially inseparable and bonded state, and the fiber surface has a composite cross section in which the polyester thermoplastic resin B covers the polyester thermoplastic resin A. Both short fibers and long fibers may be used, but long fibers are preferred from the perspective of fiber waste.

[0049] At this time, in the cross section of the composite fiber, the minimum value t of the thickness t 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 to 0.10. If it is less than 0.01, the fabric quality and abrasion resistance may be reduced due to fuzz, etc. It is preferably 0.02 or greater. If it exceeds 0.10, sufficient curl development and tensile properties may be difficult to achieve. It is preferably 0.08 or less.

[0050] In addition, in the cross section of the composite fiber of the present invention, the thickness t satisfies 1.00t min≤t≤1.05t min The perimeter of the part C t The circumference C of the composite fiber as a whole is C t ≥0.33C. Therefore, the area of ​​the polyester thermoplastic resin A in the cross section (S A ) and the area of ​​polyester thermoplastic resin B (S B Compared with conventional eccentric core-sheath composite fibers with the same ratio of C, the centers of gravity of the regions where the resins are present are separated, so that the resulting crimped fibers can form finer spirals and exhibit good crimp. Furthermore, in order to obtain crimp suitable for woven knitted fabrics with a worsted-like appearance, C is more preferably t ≥0.40C. In addition, in principle, C t <C, but C is preferred t ≤0.70C.

[0051] Furthermore, the apparent aspect ratio (D thick / D thin ) is 1.05 to 3.00. In the present invention, the apparent thickness ratio (D thick / D thin ) refers to the fiber diameter (D) of the portion of the composite fiber bundle whose width in the direction perpendicular to the fiber axis is relatively thicker than the average value under a load of 0.11 cN / dtex. thick ) and the fiber diameter (D thin The apparent thickness ratio (D thick / D thin If the fiber thickness t is less than 1.05, the resulting woven fabric will not have the worsted-spun appearance of natural fiber woven fabrics. It is preferably 1.25 or greater, and more preferably 1.40 or greater. If it exceeds 3.00, the natural appearance is lost, and the preferred appearance is not achieved. It is preferably 2.00 or less. It should be noted that the specific methods for measuring the thickness t, fiber diameter D, aspect ratio, circumference C, etc. are described in the Examples.

[0052] In the present invention, by simultaneously satisfying the above requirements (1) to (4), it is possible to simultaneously solve the problems of a worsted-spun, natural appearance, abrasion resistance that is a problem in side-by-side conjugate fibers, and stretchability that is a problem in general eccentric core-sheath types.

[0053] The cross-sectional shape of the composite fiber is not particularly limited and may be circular, elliptical, triangular, or other cross-sectional shapes. However, a circular shape is more preferred because composite fibers satisfying requirements (1) to (4) can be stably spun.

[0054] In the conjugate fiber of the present invention, the area of ​​the polyester thermoplastic resin A in the cross section (S A) and the area of ​​polyester thermoplastic resin B (S B ) ratio S 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 .

[0055] Secondly, the conjugate fiber of the present invention preferably has a hysteresis loss during recovery from elongation under a maximum load of 0.5 cN / dtex of 0.5 cN / dtex, preferably 0 to 70%, more preferably 40 to 70%. A hysteresis loss of 70% or less is preferred because clothing comprising a woven or knitted fabric using the conjugate fiber of the present invention exhibits sufficient recovery even when stretched by body movement, resulting in minimal deformation of the clothing. Furthermore, a hysteresis loss of 40% or greater is even more preferred because there is no excessive restraint caused by stretched clothing. It should be noted that the hysteresis loss is 0% or greater according to the measurement method.

[0056] The composite fiber of the present invention preferably has a thickness length ratio LR1 (L2 / L1) of the thin portion length (L2) to the thick portion length (L1) in the fiber axis direction under a measurement load of 0.00166 cN / dtex (1.5 mg / Denier (mg / denier)) of 0.90 to 1.40. By setting the measurement load to 0.00166 cN / dtex (1.5 mg / Denier), the relaxation during measurement of the composite fiber of the present invention can be mainly eliminated. For the composite fiber of the present invention, generally, through dyeing processing, the thin portion with relatively developed orientation becomes a light color, and the thick portion with undeveloped orientation becomes a dark color. By setting LR1 to 0.90 to 1.40, a dark and light mottled appearance with a better worsted-like appearance can be formed when dyeing woven knitted fabrics. If LR1 is increased, the light-colored portion can be increased; if LR1 is decreased, the dark-colored portion can be increased. Since a worsted-spun pattern in which light colors are slightly more prominent than dark colors can be made more prominent, LR1 is more preferably 1.00 or more, and even more preferably 1.10 or more.

[0057] However, in order to achieve a superior worsted-spun appearance in composite fibers with stretchability, in addition to the aforementioned LR1 of 0.90 to 1.40, the ratio of the thickness-to-thickness ratio LR2 at a test load of 0.11 cN / dtex (0.10 g / denier) to the thickness-to-thickness ratio LR1 at a test load of 0.00166 cN / dtex (1.5 g / denier) (LR2 / LR1) is preferably 1.20 to 2.10. Here, LR2 is the ratio (L4 / L3) of the thin portion length (L4) to the thick portion length (L3) of the composite fiber in the fiber axis direction at a test load of 0.11 cN / dtex. Worsted-spun woven knitted fabrics, such as wool woven knitted fabrics, also lack stretchability during use and therefore experience minimal changes in appearance. On the other hand, fabrics with stretchability and worsted-spun appearance may deteriorate in appearance during use, but the inventors' research has determined that this is due to changes in appearance caused by stretching. By setting the load within the above-mentioned range of the present invention, it is possible to suppress excessive changes in the balance of dark and light colors when stretching a woven fabric, thereby imparting a natural appearance. The reason for setting the measurement load to 0.11 cN / dtex (0.10 g / denier) is to cope with the stress of, for example, a state in which a garment containing a woven fabric using the conjugate fiber of the present invention is stretched by body movement. The conjugate fiber of the present invention exhibits coil-like crimps due to the shrinkage difference between the polyester thermoplastic resin A and the polyester thermoplastic resin B during the heat treatment of the dyeing process, but this crimp is actively exhibited in fine parts with large structural differences. Furthermore, when LR2 / LR1 is 1.20 to 2.10, the crimps in the fine parts are elongated, and the stretchability is also more excellent. By setting LR2 / LR1 to 1.20 or greater, more preferably 1.30 or greater, and even more preferably 1.40 or greater, excellent stretchability is achieved. By setting it to 2.10 or less, more preferably 2.00 or less, and even more preferably 1.90 or less, the thin portion ratio during elongation is maintained, resulting in a fine-textured appearance with excellent dark and light variegated colors. It should be noted that the values ​​for the aforementioned thick portion length and thin portion length are those measured by the methods described in the Examples.

[0058] In addition, the composite fiber of the present invention preferably has a fiber diameter (D thick ) portion, the surface of the conjugate fiber has cracks. More preferably, the cracks are formed in a direction substantially perpendicular to the longitudinal direction of the conjugate fiber. Even more preferably, the cracks are formed so that the depth of the cracks in the direction substantially perpendicular to the conjugate fiber varies along the circumference of the fiber. Furthermore, the crack depth is preferably 0.5 to 5.0 μm. This allows woven knitted fabrics using the conjugate fiber to have a finer, worsted-spun appearance and a natural, deep appearance.

[0059] Here, the depth of the crack refers to the depth measured at the deepest part of the crack. Figure 2 As schematically illustrated, cracks are formed along the circumference of the composite fiber, approximately perpendicular to its longitudinal direction. While the circumferential length of the composite fiber is not particularly limited, cracks of at least 1 / 2 the circumference of the composite fiber are preferred because they provide a natural, worsted-spun appearance, similar to that of natural fibers, when woven or knitted. In the present invention, crack depth and length are measured using an electron microscope, with the average value of 10 cracks measured within a single composite fiber being used. The specific measurement method is described in the Examples.

[0060] The average fiber diameter D of the composite fiber in the present invention ave It is preferably 10 μm to 30 μm. By being within this range, elasticity, stiffness and stretchability when made into woven knitted fabrics can be obtained, and the soft touch closer to natural wool materials can be obtained. In the present invention, the average fiber diameter D ave It is a value calculated based on the fineness of the composite fiber.

[0061] Furthermore, the conjugate fiber of the present invention is preferably in the form of a flat yarn, a crimped yarn, an air-jet-processed yarn, an air-blended yarn, a twisted yarn, or the like, depending on the desired purpose.

[0062] [Compounded mixed fibers including composite fibers, woven and knitted fabrics, and clothing]

[0063] The mixed and blended fibers of the present invention are further compounded with at least one other yarn in the composite fiber of the present invention. In addition, at least a portion of the woven knitted fabric of the present invention contains the composite fiber and / or composite blended fiber of the present invention. Thus, as described above, a natural worsted-like appearance can be formed as when natural fibers are used. In addition, in the woven knitted fabric of the present invention, the woven knitted fabric can also be composed of only the composite fiber or the composite blended fiber, but by forming the woven knitted fabric in the form of a blended yarn, composite twisted yarn, or combined twisted yarn with other yarns, a more natural worsted-like and variegated feel can be obtained, which is preferred from this aspect. In the present invention, as other yarns, there are no particular restrictions as long as they are different from the composite fiber of the present invention. Among them, polyester resins are preferably included because they have good curl and mechanical properties and excellent dimensional stability to changes in humidity and temperature. Specific examples of polyester resins include polyethylene terephthalate resins whose main repeating units are ethylene terephthalate, polypropylene terephthalate resins whose main repeating units are trimethylene terephthalate, or polybutylene terephthalate resins whose main repeating units are butylene terephthalate. It should be noted that the polyethylene terephthalate resins or polybutylene terephthalate resins may contain a small amount (usually less than 30 mol%) of a copolymer component as needed.

[0064] Furthermore, it is preferred that the other yarns combined with the composite fiber of the present invention have a difference in yarn length after dyeing, as this further enhances bulkiness. To achieve this difference in yarn length, methods include physically adjusting the feed rate of each fiber during compounding, blending fibers with lower shrinkage characteristics than the composite fiber of the present invention, or compounding by false twisting. The yarn length difference is preferably 10% or greater, as bulkiness is more readily apparent, but is preferably 30% or less, considering the physical properties of woven and knitted fabrics. A specific method for measuring the yarn length difference is described in the Examples.

[0065] Furthermore, the apparent thickness ratio (D thick / D thin ) is 1.05 to 3.00, because it is possible to express the aspect ratio of the conjugated fiber of the present invention and variegated colors with a phase shift, and the worsted-spun pattern is more natural, which is more preferable.

[0066] In the woven knitted fabric of the present invention, the proportion of the conjugate fiber and / or conjugate mixed fiber of the present invention used is preferably 30% by mass or greater, more preferably 40% by mass or greater, relative to the mass of the woven knitted fabric. It is also preferred that all of the fibers constituting the woven knitted fabric be composed of the conjugate fiber and / or conjugate mixed fiber of the present invention.

[0067] The fabric structure of the woven knitted fabric of the present invention is a woven fabric or a knitted fabric. The woven fabric weave can be selected from plain, twill, satin, and variations thereof, taking into account the desired feel and design. Furthermore, a multi-layer fabric weave, such as a double-layer fabric, can also be produced. The knitted fabric weave can be selected based on the desired feel and design. For weft knitting, examples include plain, rib, purl, tuck, float, lace mesh, and variations thereof. For warp knitting, examples include single-bar warp plain, single-bar warp satin, single-bar warp pile, single-bar warp knitted tuck, double-bar warp plain, warp satin, warp pile, warp pile-warp plain, warp satin, warp twill plain, and variations thereof. Of these, relatively simple woven knitted structures, such as plain or variations thereof, twill or variations thereof, and satin, are more preferred for achieving a fine worsted-spun look and a deep, natural appearance.

[0068] Furthermore, at least a portion of the garment of the present invention comprises the conjugate fiber or conjugate blended fiber, or woven knitted fabric of the present invention. This allows for garments that utilize the fine, worsted-spun feel of the conjugate fiber or conjugate blended fiber, or woven knitted fabric of the present invention, which is close to natural wool, and possess a deep, natural appearance and high sensuality. The garment of the present invention includes outerwear items worn as women's and men's clothing, particularly jackets, suits, bottoms, and portions thereof (e.g., front bodice, back bodice, collar, sleeves, breast pockets, and side pockets).

[0069] In addition, the clothing of the present invention is preferably washed, air-blown or air-extracted after sewing, thereby removing the fiber scraps attached to the cut portion of the cloth and the surface of the cloth from the cloth, and further suppressing the generation of fiber scraps during washing.

[0070] In the woven fabric or clothing of the present invention, the fiber waste generated during washing can be evaluated by implementing a washing test of the woven fabric or clothing and using a collection bag (filter) installed on the drain hose of the washing machine to collect the fiber waste. It should be noted that when the fiber waste and the like are affected by the washing performed before the evaluation, the washing machine should be washed in advance. There are no special restrictions on the washing method. For example, there is a method of washing the washing machine in accordance with ISO 6330 (2012) without adding the laundry and detergent to the washing machine. The washing machine is washed without adding the laundry and detergent, and the rinsing and dehydration processes are performed more than once. The conditions are set to be the same as the washing conditions to be evaluated.

[0071] At this time, the washing machine used was a Type C standard washing machine specified in ISO 6330 (2012). In addition, washing was carried out by the 4N method of the Type C standard washing machine specified in ISO6330 (2012). Regarding the fiber scraps discharged from the drain port of the washing machine, a collection group was installed on the drain hose of the washing machine to collect them. In this evaluation, "Nylon Screen" NY10-HC (purchased from Flon Industries, Ltd., catalog value: opening 10 μm) was used. It should be noted that when it is difficult to obtain "Nylon Screen" NY10-HC (manufactured by Flon Industries, Ltd., catalog value: opening 10 μm), an equivalent product within the range of opening 10 μm ± 2 μm was used.

[0072] In this method for evaluating the amount of lint generated during the washing of woven or knitted fabrics or clothing, a single piece of the fiber product to be evaluated is placed in a washing machine with a collection basket installed and washed using the aforementioned washing machine and washing conditions. However, no detergent or load cloth is used. After washing, the weight of the lint attached to the collection basket is measured. It should be noted that the term "one piece of fiber product" refers to a single piece, regardless of shape, size, or weight.

[0073] The fiber waste collected by the collection unit was then filtered through a filter that had been completely dried and its weight measured. For this evaluation, a polycarbonate membrane (K040A047A, manufactured by Advantec Toyo Co., Ltd.) was used. The filter and fiber waste were dried at 105°C for one hour and weighed. The difference between the weight and the weight before filtration was used as the fiber waste amount. The conditions for the complete drying and weight measurement were heating at 105°C for one hour, then adjusting the temperature and humidity at 20°C and 65% RH before weight measurement.

[0074] In the woven fabric and clothing of the present invention, the amount of fiber waste collected after this test can be 150 (mg / 1 fiber product) or less, and in a preferred embodiment, can be 100 (mg / 1 fiber product) or less.

[0075] [Method for producing composite fiber and woven fabric]

[0076] Next, an example of a preferred method for producing the conjugate fiber, conjugate mixed fiber, and woven / knitted fabric of the present invention will be described.

[0077] The conjugated fiber of the present invention can be produced by winding a discharged thermoplastic resin as an undrawn yarn or a semi-drawn yarn, followed by thick and thin stretching. In particular, conjugated fibers obtained by winding a semi-drawn yarn and then stretching it are preferred because the orientation difference between the polyester thermoplastic resin A and the polyester thermoplastic resin B results in excellent stretchability, particularly during dyeing, when used in woven or knitted fabrics. Furthermore, the high orientation of the polyester resin A provides excellent resistance to embrittlement due to alkali weight loss.

[0078] [Spinning process]

[0079] In the method for producing the conjugate fiber of the present invention, the polyester thermoplastic resin A and the polyester thermoplastic resin B are first melted separately, ejected from a spinning nozzle, and preferably wound as an undrawn yarn or a semi-drawn yarn at a spinning speed of 1400 m / min to 3800 m / min.

[0080] In the present invention, it is preferred to prepare the composite processed yarn of the present invention from a semi-drawn yarn because it is easy to reduce the hysteresis loss to 70% or less. Compared with an undrawn yarn, the crystallization of the semi-drawn yarn progresses, thus suppressing plastic deformation caused by a load.

[0081] The spinning temperature is preferably about the melting point (T mA 、T mB ) is +20℃~+50℃. mA 、T mB )+20℃ or more, it is possible to prevent the melted polyester thermoplastic resin A and polyester thermoplastic resin B from solidifying and clogging in the spinning machine piping. On the other hand, by (T mA 、T mB )+50°C or lower, the thermal degradation of the molten polyester thermoplastic resin A and the polyester thermoplastic resin B can be suppressed.

[0082] 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 spin fibers with high quality and stable operation.

[0083] Here, in the conjugated fiber of the present invention, as described above, the polyester thermoplastic resin A is completely covered with the polyester thermoplastic resin B in the cross section of the conjugated fiber. By forming such a cross section of the conjugated fiber, it is also possible to suppress the curvature of the ejection line caused by the difference in flow rates of the two thermoplastic resins ejected from the spinneret, which is a problem during the production of the conjugated fiber.

[0084] The composite fiber of the present invention preferably satisfies the following conditions: the minimum value tmin of the thickness t of the polyester thermoplastic resin B covering the polyester thermoplastic resin A and the thickness t in the cross section of the composite fiber satisfy 1.00t min ≤t≤1.05t min The perimeter of the part C t For precise control, it is suitable to use a spinning method using a distribution plate as exemplified in Japanese Patent Application Laid-Open No. 2011-174215, Japanese Patent Application Laid-Open No. 2011-208313, and Japanese Patent Application Laid-Open No. 2012-136804. By using such a distribution plate, t min In the above range, it is possible to min The exposure of the polyester thermoplastic resin A caused by the excessively small size can be suppressed, and the whitening phenomenon and fuzz of the woven and knitted fabric can be suppressed. Alternatively, t min The cross-sectional shape of the monofilament can be controlled by arranging the distribution holes in the final distribution plate located at the farthest downstream of the distribution plates, which are composed of multiple distribution plates.

[0085] [Stretching process]

[0086] Next, the yarn produced through the spinning step is stretched at a stretching ratio not exceeding the natural stretching ratio of the yarn using a method such as Figure 3 The stretching device as illustrated is used for stretching to form a stretched yarn. Through this process, the desired thick and thin yarns (thick and thin fancy yarns) can be obtained. For example, by performing rod stretching on a semi-stretched yarn obtained by composite spinning at a spinning speed of 2600m / min at a stretching ratio of 1.5 times, a hot rod temperature of 70°C, a setting temperature of 150°C, and a yarn speed of 300m / min, a yarn with an apparent thickness ratio of 1.05 to 3.00 can be obtained. In addition, it is preferred to stretch within the range of the lower limit of the natural stretching ratio × 1.2 times to the upper limit × 0.8 times. By making a composite fiber stretched within the above range, it is easy to adjust the ratio of the thickness-to-length ratio LR1 of the composite fiber to the thickness-to-length ratio LR2 at a load of 0.11cN / dtex (LR2 / LR1) to the range of the present invention in the dyeing process described later. When the heat shrinkage after the stretching process has a significant adverse effect on the subsequent process, in order to suppress the heat shrinkage, it is preferred to perform some kind of heat setting after the stretching process. In this case, it is also preferable to perform false twisting by a conventional method. This drawn yarn can also be used as the conjugate fiber of the present invention.

[0087] Furthermore, the stretched composite fiber can be combined with other yarns before or after winding to form a composite composite fiber. The mixing method is not particularly limited, and common methods such as interlaced mixing and taslan mixing are suitable. Heat setting, false twisting, or twisting can also be performed after mixing.

[0088] [Woven fabric forming process]

[0089] The conjugate fiber obtained in the stretching step is made into a woven fabric or a knitted fabric. Woven fabrics are woven using an air jet loom, a water jet loom, a rapier loom, a projectile loom, a shuttle loom, or the like. Knitted fabrics are knitted using a weft knitting machine such as a flat knitting machine, a full fashion knitting machine, a circular knitting machine, a computerized jacquard knitting machine, a sock knitting machine, or a circular knitting machine, or a warp knitting machine such as a tricot knitting machine, a raschel knitting machine, an air jet loom, or a Milanese warp knitting machine.

[0090] [Alkali reduction process]

[0091] Furthermore, if necessary, the woven fabric obtained in the woven fabric forming step is subjected to an alkali weight reduction treatment to achieve an alkali weight reduction rate of 5% or more, more preferably 10-15%. This step can create a state in which cracks are present throughout the surface of the composite fiber. Furthermore, a continuous weight reduction process is preferred to avoid embrittlement caused by selective weight reduction.

[0092] [Dyeing process]

[0093] Furthermore, as needed, conventional scouring, relaxation, intermediate heat setting, dyeing, and final heat setting may be performed before, after, or simultaneously with the alkali reduction step (in the present invention, these steps are sometimes collectively referred to as the "dyeing step"). To achieve the ratio of the aspect ratio LR1 of the composite fiber to the aspect ratio LR2 under a load of 0.11 cN / dtex (LR2 / LR1), which is a preferred embodiment of the present invention, the feed and tension management of each step are appropriately performed. For example, the liquid volume and flow rate are preferably controlled to ensure that the feed amount in the axial direction of the composite fiber of the present invention is within 10% in equipment such as a roll-to-roll system that can control the feed amount, and to prevent excessive tension in the travel direction in a batch-type liquid jet dyeing machine. Dyeing, which also depends on the dyeability of the thermoplastic resin constituting the composite fiber or the other yarns to be composited, is preferably performed in a dyeing solution at 110-130°C using disperse dyes or cationic dyes.

[0094] Example

[0095] The present invention will be described in detail below based on the examples. However, the present invention is not limited to these examples. It should be noted that, in the measurement of various physical properties, unless otherwise specified, the measurement was performed based on the above-mentioned method.

[0096] [Measurement method]

[0097] (1) Determination of weight average molecular weight of thermoplastic resin

[0098] As a gel permeation chromatography (GPC) testing apparatus, “TOSO GMHHR-H(S)HT” manufactured by Tosoh Corporation was used.

[0099] (2) Average fiber diameter D ave Determination of

[0100] Conjugate fibers were extracted from dyed woven and knitted fabrics, and their fineness and filament count were measured according to JIS L1013 (2010) 8.3.1B and JIS L1013 (2010) 8.4, respectively. The single-filament fineness was calculated by dividing the fineness by the number of filaments. The average fiber diameter was calculated from the obtained single-filament fineness using the following formula.

[0101] [Mathematical formula 1]

[0102]

[0103] ρ: density (g / m 3 ) In the case of polyethylene terephthalate, it is 1.38×10 6 g / m 3 .

[0104] (3) Measurement of Fiber Diameter D, Thickness t of Polyester Thermoplastic Resin B Covering Polyester Thermoplastic Resin A, and Fiber Perimeter C

[0105] A multifilament yarn containing a composite fiber is embedded with an embedding agent such as epoxy resin at 10 locations at 1 cm intervals along the fiber axis to prepare a sample. An image of each sample is captured using a transmission electron microscope (TEM) at a magnification sufficient to observe 10 or more fibers. Metallic staining is applied to enhance the contrast between the junctions of polyester thermoplastic resin A and polyester thermoplastic resin B. "WinROOF2015," manufactured by Mitani Shoji Co., Ltd., is used as image analysis software. The fiber diameter D, the resulting circumference C, and the thickness t of the polyester thermoplastic resin B are measured for all the single fibers in the observed image. Ten combinations of the obtained fiber diameter D, circumference C, and thickness t are collected and averaged. The fiber diameter D is calculated to three significant figures, and the circumference C and thickness t are calculated to two significant figures. These values ​​are used as the diameter D, circumference C, and thickness t of the present invention.

[0106] (4) Hysteresis loss rate

[0107] Conjugate fibers were extracted from woven and knitted fabrics after the dyeing process (finishing heat setting). The fibers were then stretched using a Tensilon tensile tester under the constant-rate elongation conditions specified in JIS L1013 (2010) 8.5.1. The specimen length was 20 cm and the tensile rate was 20 cm / min. The fibers were stretched from an initial load of 0.1 cN / dtex to a maximum stress of 0.5 cN / dtex. The specimen was then returned to its original length at the same rate. A hysteresis curve was plotted with elongation on the horizontal axis and stress on the vertical axis. The hysteresis loss was calculated using the following formula: the area (A1) enclosed by the elongation curve, the recovery curve, and the horizontal axis; and the area (A2) enclosed by the elongation curve, a line drawn perpendicular to the horizontal axis from the end point, and the horizontal axis (elongation axis). The hysteresis loss was calculated by rounding off to one decimal place.

[0108] Hysteresis loss = (A1 / A2) × 100.

[0109] (5) Apparent thickness ratio (D thick / D thin )

[0110] Composite fibers were extracted from a woven knitted fabric after the dyeing process (finishing heat setting), and both ends of the composite fibers were fixed under a load of 0.11 cN / dtex. The diameter of the fiber bundle was measured at 500 locations at intervals of 1.0 mm in the axial direction of the fiber using a digital microscope "VHX2000" manufactured by Keyence Co., Ltd., which was taken at a magnification of 200 times. thick ) and the fiber diameter of the fine part (D thin ) is determined by defining portions thinner than the average value of the total measured data as thin parts and portions thicker than the average value as thick parts. The boundary between the thin part and the thick part is defined as the third point of three consecutive points with a thickness greater than or equal to 1.05 times the thickness of the thin part. The boundary between the thick part and the thin part is defined as the third point of three consecutive points with a thickness less than or equal to 1.05 times the thickness of the thin part. The apparent thickness ratio is calculated by rounding off the third decimal place to two decimal places.

[0111] (6) Length of the thick part in the fiber axis (L thick ) and detail length (L thin )

[0112] Composite fibers were extracted from a woven knitted fabric after the dyeing process (finishing heat setting), and both ends of the composite fibers were fixed under a specified load. Using a digital microscope "VHX2000" manufactured by Keyence Co., Ltd., the side of the fixed sample was photographed at a magnification of 200 times. The diameter of the fiber bundle was measured continuously at intervals of 1.0 mm. The thick part length and thin part length alternating in the fiber axis were measured continuously at 50 locations each. After measuring each 50 locations, the measurement direction was reversed, and the thick part length and thin part length were measured continuously at 50 locations on the same part. The average of each 100 locations was taken as L. thick , L thin It should be noted that the determination of the thick part and the thin part is based on the above (5). The measurement results are rounded off to the third decimal place and obtained to the second decimal place.

[0113] (7) Determination of the presence and depth of cracks

[0114] Using a scanning electron microscope "S-3400N" manufactured by Hitachi, Ltd., the areas identified as thick portions in item (5) above were observed. Without applying any external force, the composite fiber was extracted from the woven and knitted fabric after finishing and heat setting, and the presence or absence of cracks was confirmed. If cracks were present, the side surfaces in a direction approximately perpendicular to the cracks were observed at a magnification of 2000x. The deepest crack depth and length were measured, and the average value of 10 cracks measured within one composite fiber was used as the crack depth.

[0115] (8) Wire length difference

[0116] A yarn of about 5 cm in length is extracted from a woven knitted fabric that has been heat-set for more than 24 hours under a humidified environment of 20°C and 65RH%, and is carefully decomposed into individual monofilaments in such a way that the fiber itself does not stretch. The decomposed monofilaments are placed on a scale plate coated with glycerin, and the fiber length is measured under a load of 0.11 cN / dtex. The average length of the monofilament group with relatively short fiber length is set as La, and the average length of the monofilament group with relatively long fiber length is set as Lb, and the calculation is performed by the following formula. All monofilaments constituting the composite mixed fiber are classified into any monofilament group according to the fiber length. 20 tests are performed, and the average value is rounded to one decimal place according to Rule B (rounding method) of JIS Z 8401 (2019).

[0117] ·Fiber length difference (%) = {(Lb-La) / La}×100.

[0118] (9) Stretchability of woven and knitted fabrics using composite fibers or composite blended fibers

[0119] The elongation in the direction of the conjugate fiber of the present invention is measured according to JIS L1096 (2010) 8.16.1 B. When the conjugate fiber of the present invention is used in both the warp and weft directions, the elongation of each of the warp and weft directions is measured and the average value is used as the result.

[0120] (10) Evaluation of the feel, worsted texture, and variegated texture of woven and knitted fabrics using composite fibers and composite mixed fibers

[0121] Ten healthy adults (5 men and 5 women) served as evaluators. Samples of woven knitted fabrics formed using the conjugate fiber of the present invention were subjected to sensory evaluation by touch (particularly the feel of bulk and surface feel) on a 5-point scale of very good (5 points), good (4 points), fair (3 points), not so good (2 points), and poor (1 point). The worsted-spun fabric and the sense of variegation were visually evaluated, and the average value of each examiner was rounded off for evaluation.

[0122] (11) Fiber scraps from fiber products

[0123] Using a C-type reference washing machine described in ISO 6330 (2012), the ISO6330 (2012) C4N method was used, using the "AQW-V700E 7kg" (manufactured by Aqua Co., Ltd.), without placing any laundry in the washing machine, and performing two rinses and draining. Specifically, the program was set to the fine wash program, the water volume was set to 40 L, the washing time was set to 15 minutes, the rinsing was set to 2 times, the dehydration was set to 7 minutes, the washing water temperature was set to 40°C, and the rinsing water temperature was set to room temperature. Next, a collection bag made of "Nylon Screen NY10-HC" (manufactured by Flon Industries, Ltd., catalog value: opening 10 μm) with an opening of 11.3 μm (measured value) was installed on the drain hose of the washing machine. Then, a piece of the fiber product to be evaluated was placed in the washing machine and washed under the washing conditions of the ISO 6330 C4N method. No detergent or load cloth was used. After washing, the fiber waste adhered to the "Nylon Screen" was filtered using a pre-weighed polycarbonate membrane ("K040A047A," manufactured by Advantec Toyo Co., Ltd.). The filtered polycarbonate membrane and fiber waste were dried at 105°C for 1 hour and weighed. The difference between the weight and the pre-filtration weight was used as the fiber waste generation amount. The weight was rounded to two decimal places after the third decimal point.

[0124] [Example 1]

[0125] Polyethylene terephthalate with a weight average molecular weight of 25,000 was used as polyester thermoplastic resin A, and polyethylene terephthalate with a weight average molecular weight of 15,000 was used as polyester thermoplastic resin B. At a spinning temperature of 290°C, the polyester thermoplastic resin A and the polyester thermoplastic resin B were fed into a spinneret having 12 ejection holes so as to form a mass conjugation ratio of 50:50. It should be noted that in the spinning of Example 1, the arrangement of the distribution holes in the final distribution plate located at the most downstream of the plurality of distribution plates was set to Figure 4 The shape shown is formed into an eccentric core-sheath type ( Figure 1 The sliver ejected from the spinneret was cooled by an air cooling device, and after being given an oil agent, it was wound up at a speed of 2600m / min by a winder and stably wound as a semi-drawn yarn with a total fineness of 100dtex and a single filament count of 12 filaments.

[0126] Then, the semi-drawn yarn was fed to a drawing device at a speed of 300 m / min. Figure 3 The stretching device shown in the figure is used to stretch the rod at a stretching ratio of 1.50 times, a hot rod temperature of 70°C, and a setting temperature of 150°C, thereby obtaining an apparent thickness ratio (D thick / D thin ) is 1.40. thin / 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.

[0127] Next, a 1 / 3 twill woven fabric was produced with warp and weft yarns obtained by twisting the drawn yarns obtained by conventional methods at 1200 T / m and a warp density of 115 yarns / 2.54 cm and a weft density of 105 yarns / 2.54 cm.

[0128] The woven fabric was then subjected to scouring, intermediate heat setting, and alkali weight reduction (weight reduction rate: 10%). The fabric was then dyed using the disperse dye "Dystar Navy Blue S-GL" at a concentration of 1.0 owf% at 130°C for 30 minutes, followed by a final heat setting at 160°C. The results are shown in Table 1.

[0129] [Example 2]

[0130] In the stretching process, the stretching ratio of the stretching device was set to 1.30 times to obtain the apparent thickness ratio (D thick / D thin ) was 1.25, a composite fiber and a woven fabric were obtained in the same manner as in Example 1. The results are shown in Table 1.

[0131] [Example 3]

[0132] In the stretching process, the stretching ratio of the stretching device was set to 1.40 times, and the apparent thickness ratio (D thick / D thin ) was 1.30, a conjugate fiber and a woven fabric were obtained in the same manner as in Example 1. The results are shown in Table 1.

[0133] [Comparative Example 1]

[0134] Conjugated fibers and woven fabrics were obtained in the same manner as in Example 1, except that polyethylene terephthalate having a weight-average molecular weight of 15,000 was used for both polyester thermoplastic resin A and polyester thermoplastic resin B. The results are shown in Table 1.

[0135] [Comparative Example 2]

[0136] In Example 1, the spinneret used was replaced with a spinneret of the type described in Japanese Patent Application Laid-Open No. 09-157941 from a distributor plate type, thereby producing a side-by-side conjugate fiber comprising polyester thermoplastic resin A and polyester thermoplastic resin B. Conjugate fibers and woven fabrics were obtained in the same manner as in Example 1. The resulting woven fabric had poor quality, with poor hand feel, worsted-spinning quality, and variegated feel. The results are shown in Table 1.

[0137] [Comparative Example 3]

[0138] In Example 1, the minimum value t of the thickness t of the polyester thermoplastic resin B covering the polyester thermoplastic resin A is t min The value of becomes 10 times, and the configuration of the distribution holes of the final distribution plate of the spinneret used is changed from Figure 4 Change to Figure 5 , a polyester thermoplastic resin A and a polyester thermoplastic resin B are prepared, (t min The results are shown in Table 1.

[0139] [Comparative Example 4]

[0140] In the stretching process, the stretching ratio in the stretching device was set to 1.90 times, and the apparent thickness ratio (D thick / D thin) was 1.00 (i.e., a yarn having a uniform fiber diameter with neither a bulging portion (thick portion) of the conjugate fiber nor a bundled portion (thin portion) of the conjugate fiber). A conjugate fiber and a woven fabric were obtained in the same manner as in Example 1. The results are shown in Table 1.

[0141] [Example 4]

[0142] In the drawn yarn produced in Example 1, the apparent thickness ratio (D thick / D thin ) was 1.15 and polyethylene terephthalate fibers (74 dtex-48f) were interwoven and mixed to give a 42% by mass composite fiber. A woven fabric was obtained in the same manner as in Example 1 except that the warp density was 82 yarns / inch and the weft density was 75 yarns / inch. The results are shown in Table 1.

[0143] [Example 5]

[0144] Conjugate fibers were produced in the same manner as in Example 1, except that the spinning speed was set at 1400 m / min to produce undrawn yarn. However, partial melting occurred during the setting step during drawing, so the setting temperature was set at 120°C to produce unmelted conjugate fibers and a woven fabric. The resulting woven fabric had a low elongation but excellent hand and spun texture. The results are shown in Table 1.

[0145] [Example 6]

[0146] Conjugate fibers and woven fabrics were obtained in the same manner as in Example 1 except that the polyester thermoplastic resin A was a polyester having a weight average molecular weight of 20,000 obtained by copolymerizing 10 mol % of isophthalic acid (IPA) relative to the acid component.

[0147] [Table 1] [Table 1]

[0148]

[0149] Description of Reference Numerals

[0150] 1: Polyester thermoplastic resin A

[0151] 2: Polyester thermoplastic resin B

[0152] 3: Composite fiber

[0153] 4: Crack

[0154] 5: Semi-stretched yarn

[0155] 6: Guide

[0156] 7: 1st feed roller

[0157] 8: Hot Rod

[0158] 9: 2nd feed roller

[0159] 10: Heater

[0160] 11: 3rd feed roller

[0161] 12: Composite fiber with thickness ratio

[0162] 13: Winding section

[0163] 14: Among the distribution holes in the final distribution plate, the distribution hole for polyester thermoplastic resin A

[0164] 15: Among the distribution holes in the final distribution plate, the distribution hole for polyester thermoplastic resin B

[0165] 16: Thickness t of the polyester thermoplastic resin B covering the 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) In the composite fiber, the apparent thickness ratio (D thick / D thin ) is 1.05~3.00; (3) In the cross section of the composite fiber, the polyester thermoplastic resin B covers the polyester thermoplastic resin A, and the minimum value t of the thickness t of the polyester thermoplastic resin B is t min The ratio of the fiber diameter D of the composite fiber (t min / D) is 0.01 to 0.10; (4) In the cross section of the composite fiber, the thickness t satisfies 1.00t min ≤t≤1.05t min The perimeter of the part C 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 The hysteresis loss rate of the composite fiber during elongation recovery under a maximum load of 0.5 cN / dtex is 0 to 70%.

3. The composite fiber according to claim 1 or 2, wherein The composite fiber has a thickness-to-length ratio LR1 (L2 / L1) of the thin part length (L2) to the thick part length (L1) in the fiber axis direction under a measuring load of 0.00166 cN / dtex of 0.90 to 1.40, and a ratio (LR2 / LR1) of the thickness-to-length ratio LR2 under a measuring load of 0.11 cN / dtex to the thickness-to-length ratio LR1 under a measuring load of 0.00166 cN / dtex of 1.20 to 2.

10.

4. The composite fiber according to claim 1 or 2, wherein At least the fiber diameter (D thick ) portion, there are cracks on the surface of the composite fiber.

5. Composite blended fibers, wherein: The conjugate fiber according to any one of claims 1 to 4 is further conjugated with at least one other yarn.

6. Woven knitted fabrics, wherein The conjugate fiber according to any one of claims 1 to 4 is contained in at least a portion of the woven knitted fabric.

7. Woven knitted fabrics, wherein The composite mixed fiber according to claim 5 is contained in at least a portion of the woven knitted fabric.

8. Clothing, including The conjugate fiber according to any one of claims 1 to 4 is contained in at least a portion of the clothing.

9. Clothing, including The composite mixed fiber according to claim 5 is contained in at least a portion of the clothing.

10. Clothing, including The woven knitted fabric according to claim 6 or claim 7 is included in at least a portion of the garment.

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