JPWO2017170823A1 - Core-sheath composite fiber, and woven fabric and fishery material using the same - Google Patents

Abstract

A core-sheath composite fiber having a core part made of a thermoplastic resin A and a sheath part made of a thermoplastic resin B other than the thermoplastic resin A, and in the cross section of the composite fiber, the sheath part has an anchor part extending into the core part. And a core-sheath composite fiber formed in an undercut shape in which the anchor part has a wider part than the base part, and a woven fabric and a fishery material using the same. Select a material that can express optimal characteristics according to the application for each of the core and sheath, and keep the amount of material used in the sheath where relatively expensive materials are required small, making it excellent as a composite fiber as a whole Therefore, it can be manufactured at a low cost while maintaining the characteristics.

Description

  The present invention relates to a core-sheath composite fiber provided with a sheath part having a specific cross-sectional structure that is difficult to peel off, and a woven fabric and a fishery material using the same.

  Composite fibers using different materials, especially core-sheath composite fibers consisting of a core and a sheath, can have both the characteristics of the material of the core and the characteristics of the material of the sheath. (For example, Patent Documents 1 to 3).

  In such a core-sheath conjugate fiber, there is a problem that peeling is likely to occur at the composite interface between the core and the sheath, and various proposals have been made for improvement of peeling (for example, Patent Document 1, 2). However, in recent years, the demand for improvement in peeling has become more advanced. For example, in industrial textile applications, the processing speed and the use speed have been increased, and the required peel strength has become higher.

  In addition, since the core-sheath composite fiber can make use of the characteristics of the different materials used as described above, for example, the core material has physical characteristics such as strength and flexibility, and the sheath material is repelled. Although it is possible to give chemical characteristics such as water resistance and chemical resistance and to have both characteristics as a composite fiber as a whole, resins that can actually be combined are limited. In particular, for the sheath part, for example, it is often desirable to use a resin having functionality such as heat resistance, water repellency, and chemical resistance. In order to limit the usage of composite fibers, and to reduce the price of the entire composite fiber, the ratio of the sheath part to the core part should be kept as low as possible while keeping the high peel strength as described above. It is desirable to reduce the amount.

  Recently, sea-island composite fibers including core-sheath composite fibers as described above have been proposed for producing island-island composite fibers that can form islands in various shapes and cross-sectional shapes of islands ( Patent Documents 4 to 6). According to this proposed technique, in the island-island composite fiber, it is possible to design the size and arrangement of the island part relative to the sea part, the cross-sectional shape, the arrangement density, etc. substantially freely, and therefore the core part in the core-sheath composite fiber. There is great expectation that the cross-sectional shape and the like of the sheath portion can be designed substantially freely, and can meet various requirements in various fields.

JP 2009-219359 A JP 2009-219360 A JP 2012-219400 A JP 2011-174215 A JP 2012-127002 A JP 2013-14872 A

  Accordingly, an object of the present invention is to focus on a recently proposed technique for manufacturing a composite fiber that can be designed substantially freely in cross-sectional form, and on the problems and requirements of conventional core-sheath composite fibers. Core-sheath composite fiber in which the sheath part can have a high peel strength with respect to the core part while being able to keep the amount of use of the sheath part material small, and fabrics and marine products using the same Is to provide.

  In order to solve the above problems, the core-sheath conjugate fiber according to the present invention is a core-sheath conjugate fiber in which the core part is made of the thermoplastic resin A and the sheath part is made of the thermoplastic resin B other than the thermoplastic resin A, In the cross section of the fiber, the sheath part has an anchor part extending into the core part, and the anchor part is formed in an undercut shape having a wider part than the root part. Consists of things.

  In such a core-sheath conjugate fiber according to the present invention, since the sheath part located around the core part has an anchor part extending into the core part, the sheath part is connected to the core part via the anchor part. It will be supported and the peeling strength with respect to the core part of a sheath part will be raised. And, when this anchor part is formed in an undercut shape having a wider part than its root part, the anchor part tries to be relatively displaced outward in the composite fiber radial direction with respect to the core part. Since the wide width portion is locked to the core portion and acts to prevent relative displacement of the anchor portion, the sheath portion can have extremely high peel strength through the anchor portion having the wide width portion. In addition, since the sheath part has a high peel strength with respect to the core part, even if the sheath part is thin, its presence is maintained without peeling around the core part, and when an expensive sheath material is used Even if it exists, it becomes possible to reduce the usage-amount of a sheath part raw material by making the sheath part into a thin layer as a whole.

  In the core-sheath conjugate fiber according to the present invention, it is preferable that the anchor portion is configured to have at least a two-stage width structure of the wide portion and the narrow portion on the root portion side. With this configuration, the wide portion can be more securely locked to the core portion with respect to the relative displacement with respect to the core portion, so that the function of preventing the peeling of the sheath portion by the anchor portion is enhanced, and the sheath portion is further peeled off. Realization of strength becomes possible.

  In the two-stage width structure of the wide part and the narrow part on the base part side as described above, the width of the wide part is preferably 1.5 times or more with respect to the narrow part on the base part side, More preferably, it is 1.8 times or more, More preferably, it is 2.0 times or more. When the width of the wide portion is 1.5 times or more, the peeling prevention function of the sheath portion by the anchor portion is further strengthened, and higher peeling strength of the sheath portion becomes possible.

  In the core-sheath composite fiber according to the present invention, it is preferable that a plurality of the anchor portions are arranged in the fiber circumferential direction of the sheath portion in the cross section of the composite fiber. By arranging the anchor portions in this way, it is possible to realize a core-sheath composite fiber in which the sheath portion is difficult to peel off in any direction of the cross section.

  In the core-sheath composite fiber according to the present invention, the area ratio of the sheath part in the cross section of the composite fiber is preferably 30% or less, more preferably 25% or less, and still more preferably 20% or less. . Although the minimum of the area ratio of the sheath part in the cross section of a composite fiber is not specifically limited, 3% or more is preferable and 5% or more is more preferable. As described above, since the core-sheath conjugate fiber according to the present invention has a high peel strength at the sheath portion, the sheath portion can be prevented from being peeled even if the sheath portion is thinned. Therefore, especially when using an expensive material for the sheath, it is possible to reduce the amount of use, and it is possible to reduce the overall cost while imparting desired functionality to the core-sheath composite fiber. become.

  Moreover, in the core-sheath conjugate fiber according to the present invention, the thermoplastic resin B may be formed of a resin having higher characteristics than the thermoplastic resin A with respect to the functions required for the sheath part. For example, the core portion mainly has physical properties such as strength and flexibility of the composite fiber, so that a general-purpose thermoplastic resin A, for example, polyamide represented by nylon 6 or nylon 66, polyethylene terephthalate, poly Thermoplastics that use resins such as butylene terephthalate, polyesters typified by polyethylene naphthalate, polyolefins typified by polyethylene, polyacetal, etc., and have superior properties with respect to the required functions, although they are relatively expensive. Resin B, for example, a resin such as fluorine resin represented by ethylene tetrafluoroethylene and polyvinylidene fluoride, polyphenylene sulfide, polyether ether ketone and the like can be used.

  For thermoplastic resins A and B, additives such as pigments, dyes, light-proofing agents, ultraviolet absorbers, antioxidants, fluorescent brighteners, crystallization inhibitors, etc., as required, do not hinder the intended performance. In the range, it can be added to the core component and / or the sheath component in the polymerization step, after polymerization, or just before spinning. In particular, when a conductivity imparting agent such as carbon black or metal powder is added, it is more suitable for industrial fabrics (since static electricity generated during a high-speed manufacturing process can be released). Further, when a filler having a specific gravity different from that of the base material resin is added, it is possible to control the floating state of the yarn in water, and therefore, it is further suitable as a marine material.

  In the thermoplastic resin B as described above, for example, when the sheath portion is required to have water repellency, antifouling property, chemical resistance, etc., the thermoplastic resin B is preferably made of a fluororesin. When the sheath portion is required to have hydrolysis resistance, chemical resistance, heat resistance, or the like, for example, the thermoplastic resin B is preferably made of polyphenylene sulfide.

  Moreover, in the core-sheath conjugate fiber according to the present invention, the fiber diameter of the core-sheath conjugate fiber is not particularly limited, but considering various practical uses, the fiber diameter may be in the range of 0.05 to 5 mm. More preferably, it is the range of 0.1-3 mm.

  The core-sheath conjugate fiber according to the present invention can be developed for various uses. The present invention also provides a woven fabric using the core-sheath conjugate fiber according to the present invention as described above. The core-sheath conjugate fiber according to the present invention is particularly suitable for industrial fabrics whose processing speed and use speed have been increased in recent years and where higher peel strength of the sheath part is required.

  In addition, the present invention also provides a marine material using the core-sheath conjugate fiber according to the present invention as described above. Examples of the fishery material to be applied include fishing lines, fishing nets, ginger nets, and the like. In particular, a marine material using a core-sheath composite fiber having a sheath according to these uses can be obtained.

  The core-sheath conjugate fiber according to the present invention can be used for sports goods such as knitted fabrics, brush bristle materials, racket guts, vehicle interior products such as car seats, interior products, and the like in addition to those described above. .

  As described above, according to the core-sheath composite fiber according to the present invention, the sheath part has a specific shape by using the composite fiber manufacturing technology capable of substantially freely designing the above-mentioned recently proposed cross-sectional shape. Even in the case where an expensive sheath material having excellent properties can be realized, and a core-sheath composite fiber having an anchor portion and high peel strength with respect to the core portion can be realized, the sheath portion is as thin as possible. The amount of material used can be kept small. Therefore, the entire composite fiber is selected by selecting a material that can exhibit the optimum characteristics according to the use for each of the core part and the sheath part, and keeping the amount of material used in the sheath part that requires a relatively expensive material small. As a result, it can be manufactured at low cost while having excellent characteristics. In particular, using the core-sheath composite fiber according to the present invention, it is possible to provide an industrial fabric or fishery material having desirable characteristics.

  Further, according to the core-sheath conjugate fiber according to the present invention, it is possible to reduce the weight of the conjugate fiber. That is, when a fiber made of a resin having a relatively large specific gravity represented by a fluorine resin is used as an industrial fabric that is driven at a high speed, a load is applied to the drive unit due to the weight of the fabric. By making such a core-sheath composite fiber, it becomes possible to reduce the specific gravity while maintaining the properties of the fiber surface, and it becomes possible to reduce the burden on the drive unit even if the use speed is high, Energy saving during driving and maintenance frequency can be reduced.

It is the whole cross-sectional view (FIG. 1 (A)) and the partial expanded cross-sectional view (FIG. 1 (B)) of the core-sheath conjugate fiber which concerns on one embodiment of this invention. It is a fragmentary cross-sectional view of the core-sheath composite fiber which shows the example of various shapes other than the shape shown in FIG. 1 of the anchor part in this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a cross section of a core-sheath conjugate fiber according to an embodiment of the present invention. The core-sheath conjugate fiber 1 shown in FIG. 1A is a core-sheath conjugate fiber in which the core 2 is made of the thermoplastic resin A and the sheath 3 is made of a thermoplastic resin B other than the thermoplastic resin A. 1, the sheath portion 3 has anchor portions 4 that extend into the core portion 2 and are arranged (equally arranged) in the fiber circumferential direction of the sheath portion 3. As shown in FIG. 1B, each anchor portion 4 is formed in an undercut shape having a wide portion 6 having a width Wb wider than the width Wa on the base portion 5 side. In the present embodiment, the anchor portion 4 is configured to have at least a two-stage width structure of a wide width portion 6 and a narrow width portion on the base portion 5 side. Moreover, in this embodiment, the width Wb of the wide width part 6 is 1.5 times or more with respect to the width Wa of the narrow width part on the base part 5 side. Furthermore, in this embodiment, the area ratio of the sheath part 3 including the anchor part 4 to the total cross-sectional area of the core-sheath conjugate fiber 1 is 30% or less.

  In the core-sheath conjugate fiber 1 according to the above embodiment, the sheath part 3 is connected to and supported by the core part 2 via the anchor part 4, but the anchor part 4 is connected to the root part 5 side. Since it is formed in an undercut shape having a wide portion 6 having a width Wb wider than the width Wa, the anchor portion 4 and eventually the sheath portion 3 are to be displaced relative to the core portion 2 outward in the composite fiber radial direction. The wide portion 6 is locked to the core portion 2 to prevent relative displacement in the direction of the anchor portion 4 (sheath portion 3). The sheath portion 3 is connected to the core portion 2 via the anchor portion 4. On the other hand, it becomes possible to have extremely high peel strength. By increasing the peel strength of the sheath portion 3 with respect to the core portion 2, the sheath portion 3 can be formed thinner, and even if the sheath portion 3 is thin, high peel strength with respect to the core portion 2 is maintained. Therefore, even when an expensive sheath material is used, the sheath 3 can be thinned to reduce the amount of the sheath material used, and the cost of the entire core-sheath composite fiber 1 can be reduced. Become. In particular, the area ratio of the sheath part 3 in the cross section of the core-sheath composite fiber 1 can be made 30% or less, and even when an expensive material is used for the sheath part 3, the amount of use is reduced. It becomes possible, and it becomes possible to aim at the cost reduction as a whole, providing desired functionality to the core-sheath conjugate fiber 1. In addition, as described above, by suppressing the area ratio of the sheath portion 3 to a small value, the specific gravity of the core-sheath composite fiber 1 as a whole can be lowered and the weight can be reduced.

  And since the said anchor part 4 is comprised by the at least 2 step | paragraph width structure of the said wide part 6 and the narrow part by the side of the base part 5, the width | variety of the wide part 6 is further narrow by the base part 5 side. By being 1.5 times or more the width of the width part, the peeling prevention function of the sheath part 3 by the anchor part 4 is further strengthened, and a higher peel strength of the sheath part 3 becomes possible. In addition, by arranging a plurality of anchor portions 4 in the fiber circumferential direction in the cross section of the core-sheath conjugate fiber 1, high peel strength of the sheath portion 3 is ensured in any direction of the cross section, and the sheath portion A core-sheath composite fiber 1 in which 3 is extremely difficult to peel is realized.

  Furthermore, regarding the sheath 3 that can be thinned as described above, if the area ratio of the sheath 3 in the cross section of the core-sheath composite fiber 1 is 30% or less, an expensive material is used for the sheath 3. Even if it exists, it becomes possible to reduce the usage-amount further, and it becomes possible to aim at the cost reduction as a whole, providing desired functionality to the core-sheath conjugate fiber 1 as a whole.

  When desired functionality is imparted to the core-sheath composite fiber 1 as a whole, for example, the core portion 2 is mainly used for general physical properties such as strength and flexibility of the composite fiber 1 in order to provide general heat. Thermoplastics that use plastic resin A such as polyamide, polyethylene terephthalate, polybutylene terephthalate, polyethylene, polyethylene naphthalate, etc., and have excellent properties with respect to the required functions for the sheath part 3 although being relatively expensive. Resins B such as polyphenylene sulfide, ethylene tetrafluoroethylene, polyvinylidene fluoride, polyetheretherketone, and the like can be used with high characteristics regarding target functionality. In particular, regarding the thermoplastic resin B constituting the sheath portion 3, for example, when the sheath portion 3 is required to have water repellency, antifouling properties, chemical resistance, etc., the thermoplastic resin B may be made of a fluororesin. Preferably, when the sheath 3 is required to have hydrolysis resistance, chemical resistance, or the like, for example, the thermoplastic resin B is preferably made of polyphenylene sulfide.

  As the shape of the anchor portion of the sheath portion in the core-sheath conjugate fiber 1 as described above, various shapes other than those shown in FIG. 1 can be adopted. Examples of various shapes are shown in FIG.

  In the example shown in FIG. 2A, the anchor portion 4a of the sheath portion 3a extending into the core portion 2a is formed in a bowl shape, and has a wide width portion Wb wider than the width Wa on the root portion side. It has an undercut shape. In the example shown in FIG. 2 (B), the anchor portion 4b of the sheath portion 3b extending into the core portion 2b has a wide-width portion formed in a partial circular shape, and is wider than the width Wa on the root portion side of the anchor portion 4b. It is formed in an undercut shape having a wide portion with a wide width Wb. In the example shown in FIG. 2C, the anchor portion 4c of the sheath portion 3c extending into the core portion 2c is formed in a T-shape, and a wide portion having a width Wb wider than the width Wa on the root portion side is formed. It has an undercut shape. In the example shown in FIG. 2 (D), the anchor portion 4d of the sheath portion 3d extending into the core portion 2d is formed in a V-shape, and a wide portion having a width Wb wider than the width Wa on the root portion side is formed. It has an undercut shape. In the example shown in FIG. 2 (E), the anchor portion 4e of the sheath portion 3e extending into the core portion 2e is formed in a cross shape, and a wide portion having a width Wb wider than the width Wa on the root portion side is formed. It has an undercut shape. In the example shown in FIG. 2 (F), the anchor portion 4f of the sheath portion 3f extending into the core portion 2f is formed in a branched shape, and a wide portion having a width Wb wider than the width Wa on the root portion side is formed. It has an undercut shape. In the example shown in FIG. 2G, the anchor portion 4g of the sheath portion 3g extending into the core portion 2g is formed in a shape in which the anchor portions having the shape as shown in FIG. 1 are stacked in a plurality of stages. The undercut shape has a wide portion having a width Wb wider than the width Wa on the base portion side. In the example shown in FIG. 2 (H), the anchor portion 4h of the sheath portion 3h extending into the core portion 2h is formed in a star shape, and a wide portion having a width Wb wider than the width Wa on the base portion side is formed. It has an undercut shape. In the example shown in FIG. 2 (I), the anchor portion 4i of the sheath portion 3i extending into the core portion 2i is formed in a hook shape, and has a wide width portion Wb wider than the width Wa on the root side. It has an undercut shape. In the example shown in FIG. 2 (J), the anchor portion 4j of the sheath portion 3j extending into the core portion 2j is formed in a saddle shape or a number 7 shape, and is wider than the width Wa on the root portion side. It is formed in an undercut shape having a wide portion of Wb. In the example shown in FIG. 2 (K), the anchor portion 4k of the sheath portion 3k extending into the core portion 2k is formed in an S-shape or a curved strip shape, and has a width Wb wider than the width Wa on the root side. It is formed in an undercut shape having a wide portion. In the example shown in FIG. 2 (L), the anchor portion 4l of the sheath portion 3l extending into the core portion 2l has a T-shaped top portion curved in FIG. 2 (C) along the sheath portion 3l. It is formed in an extending shape, and is formed in an undercut shape having a wide portion having a width Wb wider than the width Wa on the base portion side.

  Thus, the shape of the anchor portion of the sheath portion in the present invention can take various shapes, and even shapes other than the illustrated examples are included in the scope of the present invention as long as the requirements for the undercut shape in the present invention are satisfied. It is.

Examples of the present invention will be described below.
Examples 1-9, Comparative Example 1
[Production of composite fiber]
As raw materials for the core and sheath of the composite fiber, nylon 6 (noted as “Ny6” in Table 1 to be described later, “Amilan” (registered trademark) CM1021TM manufactured by Toray Industries, Inc.), nylon 66 (in Table 1 to be described later) Is represented by “Ny66”, “Amilan” (registered trademark) CM3001C-N, manufactured by Toray Industries, Inc., polyethylene terephthalate (indicated as “PET” in Table 1 described later, T755M manufactured by Toray Industries, Inc.), polyethylene naphthalate (In Table 1 described later, “PEN”, “Teonex” (registered trademark) TN8065S, manufactured by Teijin Limited), tetrafluoroethylene-ethylene copolymer (in Table 1, described below, “ETFE”, Asahi Glass Co., Ltd.) "Fluon" (registered trademark) C-88AXP), a tetrafluoroethylene-hexafluoropropylene copolymer (in Table 1 described later) Is represented by “FEP”, Daikin's neoflon EFEP: RP-4020), polyphenylene sulfide (indicated in Table 1 below as “PPS”, Toray Industries, Inc. “Torelina” (registered trademark) E2080), thermoplastic Polyester elastomer (noted as “Hytrel” in Table 1 to be described later, “Hytrel” (registered trademark) 7247 manufactured by Toray DuPont), polyoxymethylene (noted as “POM” in Table 1 to be described later), manufactured by Polyplastics “Duracon” (registered trademark) FP15X: CF2001), polyether ether ketone (denoted as “PEEK” in Table 1 to be described later, “VESTAKEEEP” (registered trademark) 3300G manufactured by Daicel Evonik) under recommended conditions And prepared. The core-sheath composite fiber was melt-spun with the composition of the core part, the sheath part, the diameter of the composite fiber, the area ratio of the sheath part, the shape and number of the anchor part as shown in Table 1.

  After the eluted fiber was cooled and solidified in water, it was stretched 4.5 times in 60 ° C warm water as the first step and 120 ° C in a dry atmosphere as the second step, and then relaxed heat set in a dry heat atmosphere To obtain a core-sheath composite fiber.

  In Comparative Example 1, as compared with Example 1, a core-sheath composite fiber having no anchor portion according to the present invention was produced. In Example 8, compared with Example 1, in Example 9, compared with Example 6, the area ratio of the sheath part was increased and the size of the anchor part (the size of the narrow part and the wide part) was increased. A core-sheath composite fiber was produced.

  The obtained core-sheath composite fiber was subjected to the following measurements and evaluations, and the results shown in Table 1 were obtained.

[Measurement of specific gravity of composite fiber]
The specific gravity of the composite fiber was measured according to the specific gravity (floating / sinking method) of JIS L 1013 (2010) 8.17.1.

[Evaluation of peel strength]
Using a yarn wear tester according to JIS L 1095 (2010) 9.10.2B method, a friction speed of 120 times / mm, a friction angle of 110 °, a reciprocating distance of 2.5 cm, a test length of 20 cm, and a friction element of φ0.6 mm Ten samples were rubbed 100 times under steel conditions. The part where the friction element hit was observed with a microscope, and the peel strength was determined according to the following criteria.
A: All the samples were integrated as a fiber, and the number of samples in which the core-sheath interface was cracked was less than 5 out of 10.
B: All samples were integrated as a fiber, and the number of samples in which cracks were observed at the core-sheath interface was 5 or more out of 10.
C: There was a sample in which the core-sheath interface peeled off and was not integrated as a fiber.

  As can be seen from the results shown in Table 1, excellent peel strength of the sheath portion is obtained with the core-sheath composite fiber according to the present invention. In particular, from the comparison between Example 1 and Comparative Example 1, the effect of improving the peel strength by the anchor portion in the present invention is clear. Moreover, from the comparison between Example 8 and Example 1, by increasing the area ratio of the sheath part and increasing the size of the anchor part (Example 8), although the specific gravity slightly increased, the peel strength of the high sheath part was increased. Could be maintained. In other words, even if the sheath area ratio is 30% or less and the amount of material used in the sheath is kept small compared to Example 8 (Example 1), the specific gravity is maintained while maintaining high peel strength. It was possible to reduce the weight of the composite fiber by reducing the above. Furthermore, from comparison between Example 9 and Example 6, by increasing the area ratio of the sheath part and increasing the size of the anchor part (Example 9), the sheath part is peeled off while maintaining the same specific gravity. The strength could be further improved. In other words, even if the sheath area ratio is 30% or less and the amount of material used in the sheath is kept small compared to Example 9 (Example 6), a practically high peel strength of the sheath is achieved. It was possible.

  The core-sheath conjugate fiber according to the present invention can be developed for all uses where improvement in peel strength of the sheath is required, and in particular, the field of fabrics including industrial fabrics, and fishery materials such as fishing lines, fishing nets, ginger nets, etc. It is suitable for these fields.

1 core-sheath conjugate fiber 2, 2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h, 2i, 2j, 2k, 2l core portion 3, 3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h, 3i, 3j, 3k, 3l sheath part 4, 4a, 4b, 4c, 4d, 4e, 4f, 4g, 4h, 4i, 4j, 4k, 4l anchor part 5 root part 6 wide part Wa narrow part width Wb wide part Width of part

Claims (11)

  A core-sheath composite fiber having a core part made of a thermoplastic resin A and a sheath part made of a thermoplastic resin B other than the thermoplastic resin A, and in the cross section of the composite fiber, the sheath part has an anchor part extending into the core part. The core-sheath composite fiber is characterized in that the anchor portion is formed in an undercut shape having a wider portion than the root portion.   The core-sheath conjugate fiber according to claim 1, wherein the anchor part is configured in at least a two-stage width structure of the wide part and a narrow part on the base part side.   The core-sheath conjugate fiber according to claim 2, wherein in the two-stage width structure, the width of the wide portion is 1.5 times or more with respect to the narrow portion on the root portion side.   The core-sheath conjugate fiber according to any one of claims 1 to 3, wherein a plurality of the anchor portions are arranged in a fiber circumferential direction of the sheath portion in a cross section of the conjugate fiber.   The core-sheath conjugate fiber according to any one of claims 1 to 4, wherein an area ratio of a sheath part in a cross section of the conjugate fiber is 30% or less.   The core-sheath composite fiber according to any one of claims 1 to 5, wherein the thermoplastic resin B is made of a resin having higher characteristics than the thermoplastic resin A with respect to a function required for the sheath portion.   The core-sheath conjugate fiber according to claim 6, wherein the thermoplastic resin B is made of a fluorine-based resin.   The core-sheath conjugate fiber according to claim 6, wherein the thermoplastic resin B is made of polyphenylene sulfide.   The core-sheath conjugate fiber according to any one of claims 1 to 8, wherein a fiber diameter is in a range of 0.05 to 5 mm.   A woven fabric using the core-sheath conjugate fiber according to any one of claims 1 to 9.   A marine material made using the core-sheath conjugate fiber according to any one of claims 1 to 9.

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