Mesh-like fiber reinforced composite material, mesh-like fiber reinforced composite molding material, and mesh-like fiber reinforced composite molded product

Abstract

Provided is a mesh-like fiber-reinforced composite material that has superior expansion / contraction and draping properties, excels in moldability into shapes with curved surfaces, has superior ventilation and prevents heat from being trapped while being lightweight and high-strength, and furthermore is highly rigid and has superior impact resistance. Also provided are a mesh-like knit structural body, a material for molding the mesh-like fiber-reinforced composite material, and a mesh-like fiber-reinforced composite material molded body. The mesh-like knit structural body (1) is formed from a plurality of vertical direction knit structures (20) that are created by chain-stitch yarns (2) being continuous in the vertical direction and being knitted while forming chain stitches (2A), vertical insertion yarns (5) that are single-stitch inserted in the vertical direction along the chain stitches, and horizontal insertion yarns (3) that are inserted into the vertical direction knit structures in a horizontal direction and bind together neighboring knit structures. The mesh-like fiber-reinforced composite material (10) is a mesh-like fiber-reinforced composite material resulting from impregnating only the knit structures and the vertical and horizontal yarns of the mesh-like knit structural body (1) with a resin (R) and curing the result. Among the chain-stitch yarns and the vertical and horizontal insertion yarns, at least the vertical insertion yarns are configured as carbon fiber strands comprising carbon fibers, and the percentage of open area of the mesh-like knit structural body is configured as 20-60%.

Description

[Technical Field]

[0001] The present invention relates to a mesh-shaped fiber-reinforced composite material, which is a composite material of a thermosetting or thermoplastic resin and a reinforcing fiber, and which has a high opening ratio due to its mesh shape, and is lightweight, high-strength, and highly impact-resistant, and is therefore suitable for use as a filter, cover, reinforcing member, and particularly as an interior / exterior member for protectors such as safety helmets and prosthetic limbs (prosthetic legs, prosthetic arms). The present invention also relates to a mesh-shaped fiber-reinforced composite material. Mesh-like The present invention relates to a material for molding a fiber-reinforced composite material, and further to a mesh-shaped fiber-reinforced composite molding obtained by shaping the material for molding a mesh-shaped fiber-reinforced composite material. [Background technology]

[0002] Conventionally, most mesh materials have been made of resin or metal, but resin is lightweight but lacks strength, while metal is strong but heavy.

[0003] This problem is particularly significant in protective gear worn for body protection, and in recent years, fiber-reinforced plastic components have been used in some cases. For example, caps with inner linings have been proposed and are commercially available, and are worn by security guards, station staff, police officers, and others as uniform caps to protect the head from unexpected falling objects or external impacts, and can also be worn by children, the elderly, and the general public as sports caps to protect the head.

[0004] Patent Document 1 discloses a hat 100 with a protective inner liner, as shown in Figures 20(a) and 20(b) attached to the present application, and the hat 100 includes a cloth cap-shaped hat body (crown) 102 and a brim 103, with a protective inner liner 110 provided inside the hat body 102. As shown in the figure, the protective inner liner 110 is fitted to the inside of the hat body 102 and has a bowl shape that is curved into a substantially spherical shape so that it can fit the person's head when worn by the person. The protective inner liner 110 is made of a fiber reinforced plastic (FRP) and includes an inner body 111 that forms the basic structure of the inner liner, a cushion member 112 that is arranged inside the inner body 111, and a cover sheet 113 that is arranged to cover the inner body 111 and the cushion member 112.

[0005] The protective inner hat 100 described in the above Patent Document 1 is lightweight and breathable, and is also excellent in impact resistance and comfort.

[0006] However, in the protective inner hat 100 described in Patent Document 1, the inner body 111, which forms the basic structure of the inner hat, is made of a fiber-reinforced plastic (FRP) material in which unidirectional or woven reinforced fibers are impregnated with a matrix resin such as a thermosetting resin or a thermoplastic resin and then cured. Therefore, although the inner body 111 is lightweight and strong, it can feel stuffy when worn for long periods of time, and it has been found that further improvement in breathability is desired. Also, as described above, the inner body 111 is shaped like a roughly spherical, curved bowl to fit a human head, and is made of a fiber-reinforced plastic (FRP) material in which a unidirectional or woven reinforced fiber sheet is impregnated with resin and then cured. However, the unidirectional or woven reinforced fiber sheet before resin impregnation has problems with stretchability and drapeability, and further improvement in moldability (shapeability) is desired.

[0007] Patent Document 2 discloses a sheet-shaped carbon fiber knitted fabric knitted using carbon fibers, and describes that the sheet-shaped carbon fiber knitted fabric has excellent stretchability and drapeability.

[0008] The present inventors have focused on the excellent stretchability and drapeability of the sheet-like knitted carbon fiber fabric described in Patent Document 2, and have discovered that a mesh-like reinforced fiber composite material produced by impregnating a sheet-like carbon fiber woven fabric with a predetermined amount of resin and curing it while maintaining the predetermined open area ratio of the sheet-like knitted carbon fiber fabric provides excellent breathability and prevents stuffiness, and is also lightweight and strong when used as a material for constituting the basic structure of interior materials (innerwear) for hats, various types of protectors, and prosthetic limbs (artificial legs, artificial hands), or exterior materials (frames).

[0009] Therefore, the present inventors have developed a method for manufacturing a semiconductor device, as described in Patent Document 3 and as illustrated in FIGS. 21(a) and 21(b) attached to the present application, (a) A mesh-like knitted structure 1A having gaps G formed by a plurality of vertical knitted structures 20 produced by knitting a chain stitch yarn 2 continuously in a vertical loop shape while forming chain stitches 2A, and an insertion yarn 3 inserted laterally into the vertical knitted structures 20 and binding adjacent knitted structures 20 together; (b) A mesh-shaped fiber reinforced composite material 10A formed into a curved shape in which only the knitted structure 20 (chain stitch yarn 2) and the insertion yarn 3 in the mesh-shaped knitted structure 1A are impregnated with resin R and hardened, (c) at least a part of the chain stitch yarn 2 and the inserting yarn 3 is a carbon fiber strand made of carbon fiber, (d) The mesh-like knitted structure 1A has an opening ratio of 20 to 60%, and the mesh-like fiber-reinforced composite material 10A has voids G in its configuration.

[0010] The mesh-like knitted structure 1A used in the mesh-like fiber-reinforced composite material 10A described in Patent Document 3 has excellent stretchability and drapeability, and excellent moldability (shapeability) into curved shapes, because the reinforcing fibers used are not straight but have a knitted structure.Furthermore, because it has voids G, it has excellent breathability and can prevent stuffiness, is lightweight and has sufficient strength, and has the characteristics of being able to form the basic structure of interior materials (innerwear) for hats, various types of protectors, prosthetic limbs (prosthetic legs, prosthetic hands), etc., or exterior materials (frames).

[0011] Meanwhile, the present inventors have conducted further research and experiments on the mesh-like fiber-reinforced composite material 10A described in Patent Document 3. As a result, they have found that, although the mesh-like knitted structure 1A used in the mesh-like fiber-reinforced composite material 10A described in Patent Document 3 has excellent stretchability and drapeability and is excellent in formability into curved shapes, as described above, due to its stretchability, when the mesh-like fiber-reinforced composite material 10A is impregnated with resin and hardened, i.e., when it is made into an FRP structure, there is a problem in that the resin breaks under slight external force. Therefore, when the mesh-like fiber-reinforced composite material 10A using such a mesh-like knitted structure 1A is used in a hat or the like, if stress (impact) is applied to the surface of the hat by a dropped object or the like, bending (distortion) may occur in the stressed portion, making the hat prone to deformation and prone to reducing mechanical strength such as tensile strength and bending elasticity. Therefore, even if carbon fiber strands made of carbon fiber are used for at least some of the chain stitch yarns 2 and the insert yarns 3, as described above, due to their excellent elasticity and drapeability, the amount of deformation (amount of deflection) due to impact is large, and it has been found that further improvements are desired to obtain even greater strength and impact resistance.

[0012] Therefore, although the present inventors are in a different technical field in terms of application, they focused on the structure of the continuous fiber reinforcement member, i.e., the reinforcing fiber sheet, used to produce the fixing anchor described in Patent Document 4. That is, as shown in Figures 22(a), (b), and 23 attached to this application, the reinforcing fiber sheet 1B for the fixing anchor described in Patent Document 4 has a chain stitch portion (knitted structure) 20 produced by knitting a restraining yarn (i.e., chain stitch yarn) 2 in a loop shape in the vertical direction while forming chain stitches 2A, and continuous fiber strands 50 are arranged orthogonally within the chain stitches 2A of this knitted structure 20.

[0013] In addition, in the knitted structure 20 that restrains each continuous fiber strand 50, adjacent knitted structures 20 are bound together by an insertion yarn 3. That is, the insertion yarn 3 is inserted laterally into the knitted structure 20, and is entangled at predetermined intervals along the longitudinal direction (i.e., the vertical direction) of the continuous fiber strands 50 with the knitted structure 20 knitted to surround the continuous fiber strands 50, thereby maintaining the shape of the multiple continuous fiber strands 50 in a planar state, i.e., a reinforcing fiber sheet state. That is, according to the reinforcing fiber sheet 1B described in Patent Document 4, the knitted structure 20 is formed by knitting the restraining yarns 2 continuously in the vertical direction and in a planar state, and continuous fiber strands 50 formed by bundling a large number of continuous reinforcing fibers in one direction are inserted into this knitted structure 20 continuously knitted in the vertical direction. The shape of each continuous fiber strand 50 inserted into the vertical knitted structure 20 is maintained by being connected by an insertion yarn 3 inserted laterally into the vertical knitted structure 20. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] Utility Model Registration No. 3187008 [Patent Document 2] Patent No. 4822528 [Patent Document 3] Patent No. 6362454 [Patent Document 4] Patent No. 4463657 Summary of the Invention [Problem to be solved by the invention]

[0015] Therefore, based on the technology described in Patent Document 4, the inventors inserted reinforcing fiber yarns 50 with vertical needles 1 into a plurality of vertical knitted structures 20, which are produced by knitting chain stitch yarns 2 in a continuous loop shape in the vertical direction to form chain stitches 2A in the mesh-like knitted structure 1A described in Patent Document 3, and inserted horizontal insertion yarns 3 horizontally into the vertical knitted structure 20 to produce a sheet-like mesh-like knitted structure, which they then impregnated with resin to produce a mesh-like fiber-reinforced composite material having a structure similar to that of the mesh-like fiber-reinforced composite material described in Patent Document 3, and continued to conduct research and experiments on this composite material.

[0016] While such a mesh-shaped fiber-reinforced composite material was able to achieve increased tensile strength and reduced tensile strain, it was found that when stress (impact) is applied to the surface of a hat using the mesh-shaped fiber-reinforced composite material, for example, by a dropped object, the chain stitch yarn 2 (knit structure 20) in the vertical direction that holds the reinforcing fiber yarns in the vertical direction in the stressed area lacks rigidity, causing the chain stitch yarn 2 to break, resulting in the mesh-shaped fiber-reinforced composite material not fully fulfilling the function of the reinforcing fiber yarn 50 that ensures the strength and impact resistance of the mesh-shaped fiber-reinforced composite material. Therefore, it was found that further improvements are needed to increase rigidity and obtain sufficient strength and impact resistance even when, for example, an object falls on the top of the hat.

[0017] Therefore, the object of the present invention is to provide a mesh-like fiber-reinforced composite material that is superior in stretchability and drapeability, moldability into a curved shape, and breathability, preventing stuffiness, and is lightweight and strong, and also has high rigidity and excellent impact resistance, compared to conventional materials. , mesh The present invention provides a material for molding a fiber-reinforced composite material and a mesh-shaped fiber-reinforced composite molding. [Means for solving the problem]

[0018] The above object is to provide a mesh-shaped fiber-reinforced composite material according to the present invention. , mesh In summary, according to the first aspect of the present invention, a mesh-like knitted structure is provided, which is formed by a plurality of knitted structures in the vertical direction, each knitted structure being made by knitting a chain stitch yarn continuously in the vertical direction while forming chain stitches, a vertical insertion yarn inserted in one needle in the vertical direction along the chain stitches, and a horizontal insertion yarn inserted in the horizontal direction relative to the knitted structures in the vertical direction and binding adjacent knitted structures together, A mesh-shaped fiber reinforced composite material in which only the knitting structure and the warp and weft insertion yarns in the mesh-shaped knitted structure are impregnated with a resin and hardened, At least the warp insert yarns of the chain stitch yarns and the warp and weft insert yarns are carbon fiber strands made of carbon fiber, The opening ratio of the mesh-like knitted structure is 20 to 60%. A mesh-like fiber-reinforced composite material is provided.

[0019] According to the second aspect of the present invention, there is provided a mesh-like knitted structure formed by a plurality of vertical knitting structures produced by knitting a chain stitch yarn continuously in the vertical direction while forming chain stitches, a vertical insertion yarn inserted vertically along one needle along the chain stitches, and a horizontal insertion yarn inserted horizontally into the vertical knitting structures and binding adjacent knitting structures together, A mesh-shaped fiber reinforced composite material obtained by forming the mesh-shaped knitted structure into a predetermined shape, and then impregnating only the knitting structure and the warp and weft insertion yarns in the mesh-shaped knitted structure with a resin and hardening the resin, At least the warp insert yarns of the chain stitch yarns and the warp and weft insert yarns are carbon fiber strands made of carbon fiber, The opening ratio of the mesh-like knitted structure is 20 to 60%. A mesh-like fiber-reinforced composite material is provided.

[0020] According to one embodiment of the first and second present inventions, the resin impregnated into the mesh-like knitted structure is a thermoplastic resin such as a thermoplastic epoxy resin, a phenoxy resin, a polycarbonate resin, a polyester resin, a polyurethane resin, a polyamide resin, a polyetherimide resin, or a polyetheretherketone resin; or a thermosetting resin such as a room temperature curing or thermosetting epoxy resin, a vinyl ester resin, an MMA resin, an acrylic resin, an unsaturated polyester resin, or a phenolic resin.

[0021] According to the third aspect of the present invention, there is provided a mesh-like knitted structure formed by a plurality of vertical knitting structures produced by knitting a chain stitch yarn continuously in the vertical direction while forming chain stitches, a vertical insertion yarn inserted into one needle in the vertical direction along the chain stitches, and a horizontal insertion yarn inserted horizontally into the vertical knitting structures and binding adjacent knitting structures together, A mesh-shaped fiber reinforced composite material in which only the knitted structure and the warp and weft insertion yarns in the mesh-shaped knitted structure are impregnated with a resin, hardened, and then shaped into a predetermined shape, At least the warp insert yarns of the chain stitch yarns and the warp and weft insert yarns are carbon fiber strands made of carbon fiber, The opening ratio of the mesh-like knitted structure is 20 to 60%. A mesh-like fiber-reinforced composite material is provided.

[0022] According to one embodiment of the third invention, the resin impregnated into the mesh-like knitted structure is a thermoplastic resin such as a thermoplastic epoxy resin, a phenoxy resin, a polycarbonate resin, a polyester resin, a polyurethane resin, a polyamide resin, a polyetherimide resin, or a polyetheretherketone resin.

[0023] According to one embodiment of the present invention, the weft insertion yarn is inserted at two, three, or four needles transversely to the vertical knitting structure, or the weft insertion yarn is inserted at two, three, or four needles transversely to the vertical knitting structure, and is arranged separately in front of and behind the vertical insertion yarn on the front and back of the knitted fabric. According to another embodiment, the weft insertion yarn is knitted at regular intervals into the vertical knitting structure. According to yet another embodiment, the chain stitch yarn and the weft insertion yarn are yarns made from organic fibers such as polyester, polyamide, polyacrylonitrile, polyvinyl alcohol, and polyolefin fibers, and aramid fibers; metal fibers such as titanium and steel fibers; and inorganic fibers such as carbon and glass fibers, either alone or in combination.

[0024] According to another embodiment of the present invention, the weft insertion yarns are arranged linearly in a transverse direction relative to the longitudinal knitting structure, and the weft insertion yarns are carbon fiber strands made of carbon fiber.

[0025] According to another embodiment of the present invention, the chain stitch yarn has a fineness of 10 to 600 dtex.

[0026] According to another embodiment of the present invention, the warp insertion yarns are (a) A carbon fiber strand of PAN-based carbon fiber having 24,000 or less carbon fiber filaments and a fineness of 16,000 dtex or less, or (b) A carbon fiber strand of pitch-based carbon fiber having 12,000 or less carbon fiber filaments and a fineness of 6,000 dtex or less.

[0027] According to another embodiment of the present invention, the weft insertion yarns have a fineness of 10 to 600 dtex, and are used in a state where 2 to 4 yarns are pulled together, so that the total fineness is 700 to 2500 dtex.

[0029] Also, 4According to the present invention, a mesh-like knitted structure is formed by a plurality of vertical knitting structures produced by knitting a chain stitch yarn continuously in the vertical direction while forming chain stitches, a vertical insertion yarn inserted into one needle in the vertical direction along the chain stitches, and a horizontal insertion yarn inserted horizontally into the vertical knitting structures and binding adjacent knitting structures together, A mesh-shaped fiber-reinforced composite molding material is provided in which only the knitting structure and the warp and weft insertion yarns in the mesh-shaped knitted structure are impregnated with resin.

[0030] Also, 5 According to the present invention, there is provided a mesh-shaped fiber-reinforced composite molding obtained by shaping the above-mentioned mesh-shaped fiber-reinforced composite molding material. [Effects of the Invention]

[0031] The mesh-shaped fiber-reinforced composite material of the present invention has excellent stretchability and drapeability, and is excellent in moldability into shapes having curved surfaces. Moreover, it has excellent breathability, can prevent stuffiness, is lightweight and has sufficient strength, and has high rigidity and improved impact resistance. In particular, it is ideal as a component constituting the basic structure of interior materials (innerwear) for hats, various protectors, prosthetic limbs (prosthetic legs, prosthetic hands), etc., or exterior materials (frames). Furthermore, the mesh-shaped fiber-reinforced composite material of the present invention has excellent stretchability and drapeability, and is excellent in moldability into shapes having curved surfaces. Moreover, it has excellent breathability, can prevent stuffiness, is lightweight, has sufficient strength, and has high rigidity and improved impact resistance. In particular, it is ideal as a component constituting the basic structure of interior materials (innerwear) for hats, various protectors, prosthetic limbs (prosthetic legs, prosthetic hands), etc., or exterior materials (frames), etc. Mesh pattern The mesh-shaped fiber-reinforced composite molding material can be suitably produced from the fiber-reinforced composite molding material, and the mesh-shaped fiber-reinforced composite molding material can be shaped to suitably produce a mesh-shaped fiber-reinforced composite molding of a desired shape. [Brief explanation of the drawings]

[0032] [Figure 1] FIG. 1 is a partial knitted structure diagram showing one embodiment of a mesh-like knitted structure used in the present invention. [Figure 2] Figure 2(a) is a partially enlarged schematic diagram of the mesh-like knitted structure shown in Figure 1, and Figure 2(b) is a schematic cross-sectional diagram taken along line AA in Figure 2(a), illustrating the resin impregnation state of the mesh-like knitted structure. [Figure 3]FIG. 3 is a diagram showing the structure of the mesh-like knitted structure shown in FIG. [Figure 4] FIG. 4 is a partial knitted structure diagram showing another embodiment of the mesh-like knitted structure used in the present invention. [Figure 5] FIG. 5 is a partial knitted structure diagram showing another embodiment of the mesh-like knitted structure used in the present invention. [Figure 6] FIG. 6 is a partial knitted structure diagram showing another embodiment of the mesh-like knitted structure used in the present invention. [Figure 7] FIG. 7 is a partial knitted structure diagram showing another embodiment of the mesh-like knitted structure used in the present invention. [Figure 8] FIG. 8 is a diagram showing the structure of the mesh-like knitted structure shown in FIG. [Figure 9] FIG. 9 is a partial knitted structure diagram showing another embodiment of the mesh-like knitted structure used in the present invention. [Figure 10] FIG. 10 is a diagram showing the structure of the mesh-like knitted structure shown in FIG. [Figure 11] FIG. 11 is a partial knitted structure diagram showing another embodiment of the mesh-like knitted structure used in the present invention. [Figure 12] FIG. 12 is a partial knitted structure diagram showing an example of a conventional mesh-like knitted structure. [Figure 13] FIG. 13 is a diagram showing the structure of the mesh-like knitted structure shown in FIG. [Figure 14] FIG. 14 is a partial knitted structure diagram showing another embodiment of the mesh-like knitted structure used in the present invention. [Figure 15] FIG. 15 is a partial knitted structure diagram showing another embodiment of the mesh-like knitted structure used in the present invention. [Figure 16] FIG. 16 is a partial knitted structure diagram showing another embodiment of the mesh-like knitted structure used in the present invention. [Figure 17] FIG. 17 is a diagram showing the structure of the mesh-like knitted structure shown in FIG. [Figure 18]18(a) to 18(e) are diagrams illustrating an embodiment of a method for molding a mesh-shaped fiber-reinforced composite material according to the present invention. [Figure 19] 19(a) and 19(b) are diagrams illustrating another embodiment of the method for molding a mesh-shaped fiber-reinforced composite material according to the present invention. [Figure 20] 20(a) and (b) are diagrams showing an embodiment of a hat in which the mesh-shaped fiber-reinforced composite material of the present invention can be used as an inner material. [Figure 21] FIG. 21(a) is a partial knitted structure diagram showing an example of a conventional mesh-like knitted structure, and FIG. 21(b) is a cross-sectional schematic diagram for explaining the resin impregnation state of the mesh-like knitted structure. [Figure 22] 22(a) and 22(b) are partial plan views showing another example of a conventional mesh-like knitted structure. [Figure 23] FIG. 23 is a schematic diagram of the mesh-like knitted structure shown in FIGS. 22(a) and 22(b). [Figure 24] Figures 24(a) and (b) are diagrams illustrating a test device for evaluating the drapeability of a mesh-like knitted structure, where Figure 24(a) is a photograph showing a picture frame jig showing the state in which a test piece of the mesh-like knitted structure is fixed, and Figure 24(b) is a diagram illustrating the shape and dimensions of the test piece of the mesh-like knitted structure. DETAILED DESCRIPTION OF THE INVENTION

[0033] Hereinafter, the mesh-shaped fiber reinforced composite material according to the present invention will be described. , mesh The fiber-reinforced composite molding material and the mesh-shaped fiber-reinforced composite molding will be described in more detail with reference to the drawings.

[0034] In this specification, "hardening" includes not only hardening of a thermosetting resin by forming a three-dimensional network structure, but also solidification of a thermoplastic resin from a fluid state.

[0035] Example 1 An embodiment of a mesh-shaped fiber-reinforced composite material 10 according to the present invention will be described with reference to Fig. 1, Fig. 2(a), (b), and Fig. 3. Fig. 1 shows a mesh-shaped fiber-reinforced composite material 10 according to the present invention. Used in 2(a) is a partially enlarged schematic view of a mesh-like knitted structure, i.e., a mesh-like fiber sheet 1, which is a sheet-like reinforcing fiber knitted fabric, particularly a sheet-like reinforcing fiber warp knitted fabric, and FIG. 2(b) is a partially enlarged schematic view of a cross section taken along line AA in FIG. 2(a), which is a view for explaining the resin impregnation state of the mesh-like knitted structure. Used in FIG. 1 is a structure diagram of a mesh-like knitted structure 1.

[0036] The mesh-shaped fiber reinforced composite material 10 according to the present invention is a mesh-shaped fiber reinforced composite material (FRP) obtained by impregnating and hardening each constituent yarn of the mesh-shaped knitted structure 1 shown in Fig. 1 with a resin R, as shown in Fig. 2(b). This mesh-shaped fiber reinforced composite material 10 is a molded product formed into a predetermined shape (sometimes simply referred to as a "shape having a curved surface" or a "predetermined shape") having at least a curved area to form the basic structure of, for example, a hat as shown in Figs. 20(a) and 20(b), various protectors, interior materials (innerwear) for prosthetic limbs (artificial legs, artificial hands), or exterior materials (frames).

[0037] To further explain, the present invention Used inAs shown in Fig. 1, the mesh-like knitted structure 1 is characterized in that it is formed into a sheet shape by a plurality of knitted structures 20 (20a, 20b), i.e., double vertical knitted structures 20 (20a, 20b) of a front side knitted structure 20a and a back side knitted structure 20b, which are produced by knitting chain stitches 2 (2a, 2b) in a loop shape continuously in the vertical direction and alternately forming chain stitches 2A on the front side and back side of the knitted fabric, i.e., double vertical knitted structures 20 (20a, 20b) of a front side knitted structure 20a and a back side knitted structure 20b, a vertical insertion yarn 5 inserted into one needle in the front side knitted structure 20a and the back side knitted structure 20b of the knitted structures 20 (20a, 20b), and a horizontal insertion yarn 3 inserted horizontally relative to the vertical knitted structures 20 and binding adjacent knitted structures 20. At least the vertical insertion yarns 5 use carbon fiber strands made of carbon fiber as reinforcing fibers. The chain stitch yarns 2 and the weft insert yarns 3 can be carbon fiber strands made of carbon fiber as the reinforcing fibers, like the warp insert yarns 5, but other reinforcing fibers can also be used. These reinforcing fibers will be described in detail later. The mesh-like knitted structure 1 can be formed into a sheet, web, or ribbon shape.

[0038] After or before the mesh-like knitted structure 1 is shaped into a predetermined shape, as described above with reference to Figures 2(a) and (b), resin R is impregnated only into the knitted structure 20 (20a, 20b) consisting of chain stitch yarns 2 (2a, 2b) in the mesh-like knitted structure 1, the vertical insert yarns 5, and the horizontal insert yarns 3. That is, as will be described in detail later, the mesh-like knitted structure 1 is formed into a predetermined shape, and then only the knitting structure 20 (20a, 20b) consisting of the chain knit yarns 2 (2a, 2b) in the mesh-like knitted structure 1 and the vertical and horizontal inserted yarns 5, 3 are impregnated with resin R and hardened to form a mesh-like fiber reinforced composite material 10 of a predetermined shape; alternatively, the mesh-like knitted structure 1 is first impregnated with resin R only the knitting structure 20 (20a, 20b) and the vertical and horizontal inserted yarns 5, 3 and hardened, and then heated and molded to form a mesh-like fiber reinforced composite material 10 of a predetermined shape.

[0039] In the mesh-like fiber reinforced composite material 10 according to the present invention, the mesh-like knitted structure 1 is a knitted fabric with loops extending in three dimensions, so the fabric (mesh-like knitted structure 1) and its molded product (mesh-like fiber reinforced composite material 10) have a thickness that cannot be obtained with FRP materials molded using woven fabrics, and this thickness provides the rigidity of the molded product (FRP). On the other hand, in woven fabrics, the reinforcing fibers tend to flatten, and even after molding, the molding pressure causes the fibers to spread flat, resulting in a thin molded product and a lack of rigidity.

[0040] Generally, chain stitch yarns in a knitted fabric base material exist in the most stable curved shape within the knitted fabric, so even when they are used as a fiber-reinforced composite material, high strength characteristics cannot be expected. However, in the present invention, for example, when shaping into a hemispherical shape, each chain stitch yarn, which is a reinforcing fiber, is hardened in a state in which it is stretched radially (in the stretching direction) from the apex of the hemisphere as it is shaped. Therefore, it exhibits high strength, especially against compression from the apex, and is ideal for molded products with curvature.

[0041] In particular, in the mesh-like fiber reinforced composite material 10 according to the present invention, the mesh-like knitted structure 1 has a double vertical knitted structure 20 (20a, 20b) of a front side knitted structure 20a and a back side knitted structure 20b, which are produced by knitting chain stitch yarns 2 (2a, 2b) in a continuous loop shape in the vertical direction to form double chain stitches 2A (2Aa, 2Ab) of a front side chain stitch 2Aa and a back side chain stitch 2Ab, and a single needle vertical insertion yarn 5 is linearly inserted into the front side knitted structure 20a and the back side knitted structure 20b of the knitted structure 20 (20a, 20b), and this single needle vertical insertion yarn 5 is a carbon fiber strand made of carbon fiber.

[0042] Thus, the present invention Used in In the mesh-like knitted structure 1, the carbon fiber strand is inserted as a single-needle vertical insertion yarn 5, so that the strength and elastic modulus in the vertical direction are increased compared to the conventional mesh-like knitted structure 1A shown in Figures 21(a) and (b), and the strength and impact resistance can be improved. Used inThe mesh-like knitted structure 1 has a vertical knitted structure 20 (20a, 20b) consisting of a front knitted structure 20a and a back knitted structure 20b made on both sides of the knitted fabric, and a horizontally inserted yarn 3 that binds this vertical knitted structure 20 (20a, 20b) together, which acts as a cushioning material for the carbon fiber yarn that is the one-needle vertically inserted yarn 5, improving impact resistance.

[0043] The mesh-like fiber-reinforced composite material 10 constructed according to the present invention may have its elasticity restricted by the single-needle vertically inserted yarn 5 in the mesh-like knitted structure 1, and further by the thickening of the horizontally inserted yarn 3, as will be described in more detail below. However, since the mesh-like knitted structure 1 has a mesh structure that is easily shear deformed, it can be easily shaped into a three-dimensional shape, such as a hemisphere, and this does not pose a problem.

[0044] The present invention Used in In evaluating the drapeability of a mesh-like knitted structure using a picture frame jig according to the picture frame method, the load measured when a 50 mm displacement is applied in a direction at an angle of 45° to the longitudinal and lateral directions of the stitches is preferably 100 N or less, more preferably 50 N or less. The smaller the measured load, the greater the deformation of the mesh-like knitted structure can be with a smaller force, making it easier to form it into a three-dimensional shape such as a hemisphere.

[0045] The evaluation of drapeability using a picture frame jig was carried out by fixing a mesh-like knitted structure (test piece 1T) cut to the shape shown in Figure 24(b) to a square metal jig 300 with a distance of 285 mm between the fulcrums (movable axes 301a to 301d) on each side and four movable corners, as shown in Figure 24(a), and measuring the load measured when a 50 mm displacement was applied in the tensile direction from the diagonal (45°) direction using a universal testing machine at a crosshead speed of 300 mm / min.The smaller the measured load, the easier the knitted structure is to deform.

[0046] Next, the mesh-like knitted structure 1 constituting the mesh-like fiber-reinforced composite material 10 of the present invention will be further described.

[0047] (Mesh-like knitted structure) In this embodiment, the mesh-like knitted structure 1 is made of a knitting pattern 20 (20a, 20b), i.e., chain stitch yarns 2 (2a, 2b), weft insert yarns 3, and one needle warp insert yarn 5, and at least one needle warp insert yarn 5 uses a carbon fiber bundle (carbon fiber strand) made of carbon fiber as the reinforcing fiber. The chain stitch yarns 2 (2a, 2b) and the weft insert yarn 3 can also use a carbon fiber bundle (carbon fiber strand), but in this embodiment, other reinforcing fibers are used. The reinforcing fibers that can be used for these chain stitch yarns 2 (2a, 2b) and the warp and weft insert yarns 5, 3 will be described in detail later.

[0048] According to this embodiment, the mesh-like knitted structure 1 has a double knitted structure 20 (20a, 20b) formed by arranging a large number of chain stitch yarns 2 (2a, 2b) in parallel while forming continuous loops in the vertical direction (the length direction of the fiber sheet), and a three-needle swing weft insertion yarn 3 is knitted into this knitted structure 20 (20a, 20b). In this embodiment shown in Figure 1, two parallel three-needle swing weft insertion yarns 3 cross every three yarns in the knitted structure 20 (20a, 20b) every course and reverse direction (the guide is swung by three needles every course), thereby forming a warp knitted fabric.

[0049] The mesh-like knitted structure 1 used in the present invention is not limited to the above-mentioned embodiment. The number of three-needle weft-insertion yarns 3 is not limited to two, and four or other numbers of yarns can be used.

[0050] In the embodiment shown in Fig. 1, the weft insert yarn 3 crosses every third knitting structure 20 (20a, 20b) in every course, reversing its direction (three needles inserted in every course) to form a warp knitted fabric, but other configurations are also possible. That is, in the embodiment shown in Fig. 4, the weft insert yarn 3 crosses every fourth knitting structure 20 (20a, 20b) in every course, reversing its direction (four needles inserted in every course), in the embodiment shown in Fig. 5, the insert yarn crosses every second knitting structure 20 (20a, 20b) in every third course, reversing its direction (two needles inserted in every three courses), and in the embodiment shown in Fig. 6, the weft insert yarn 3 crosses every second knitting structure 20 (20a, 20b) in every fourth course, alternating every two courses (two needles inserted in every two courses, four courses) to form a warp knitted fabric.

[0051] In this embodiment, in the sheet-like mesh knitted structure (sheet material) 1, the chain stitch yarns 2 (2a, 2b) form loops, and the weft insertion yarns 3 are knitted into the loops and integrated. Therefore, when the sheet material is pulled in the longitudinal direction, for example, the loops stretch, and the arrangement angle of the weft insertion yarns 3 also changes accordingly, so the sheet material stretches easily and is highly stretchable and drapeable. This drapeability largely determines the ability to form complex curved surfaces. Because the mesh knitted structure 1 has such excellent stretchability and drapeability, it can be formed into complex curved surfaces.

[0052] Furthermore, in the mesh-like knitted structure 1, the chain stitch yarns 2 (2a, 2b) form loops, and the weft insertion yarns 3 are also arranged in a folded form in the width direction, resulting in a multidirectional fiber arrangement overall, so when made into a composite material (FRP) 10, it does not exhibit extreme anisotropy like unidirectional materials or woven fabrics. Therefore, for example, when multiple mesh-like knitted structures 1 are stacked and used, pseudo-isotropic properties can be obtained even if multiple sheets are stacked in the same direction, without having to shape each sheet individually so that the fiber axes are different, and the molding process is extremely simplified.

[0053] In this embodiment, the mesh-like knitted structure 1 is a double Russell knitted fabric, in which chain stitch yarns 2 (2a, 2b) form vertical loops in a double knitted structure 20 (20a, 20b), and weft insertion yarns 3 are knitted into the loops and integrated, so the shape is stable and the fiber orientation is not disturbed during the layering process, which is preferable, but not limited to this. A single Russell knitted fabric is also acceptable, and there are many knitted structures, such as a chain stitch variation structure, a Denbigh structure, or a combination of a chain stitch structure and a Denbigh structure. These can be designed appropriately depending on the intended use and usage pattern.

[0054] Here, we will explain the one-needle vertical insertion yarn 5 that is linearly inserted into the front side knitted structure 20a and the back side knitted structure 20b of the knitted structure 20 (20a, 20b). A flexible continuous carbon fiber strand is used as the vertical insertion yarn 5. The carbon fiber strand 5 is formed by bundling a large number of continuous carbon fibers that are drawn parallel to one direction, and this fiber bundle forms the carbon fiber strand 5.

[0055] The carbon fiber used in this example is a PAN-based carbon fiber manufactured by heating a polyacrylonitrile fiber bundle in an oxygen atmosphere to oxidize and flame-retard the fiber, and then carbonizing the resulting fiber bundle under tension in a high-temperature inert gas atmosphere. Therefore, although the processing conditions vary, the resulting carbon fiber has a high strength and high modulus of elasticity, with a tensile strength of 3 to 10 GPa and a tensile modulus of elasticity of 200 to 600 GPa, resulting in uniform properties with little variation.

[0056] The number of filaments and the fineness of the continuous carbon fiber strands 5 used in this example are 24,000 or less and 16,000 dtex or less, and may be, for example, about 18,000 or 12,000 dtex, but if the carbon fiber strands are too thick, the intersections of the chain stitch yarns 2 and the inserting yarns 3 will be thick, and there will also be voids in the knitted structure 20 where no carbon fibers are present, resulting in an FRP with significant irregularities. Therefore, it is preferable that the number of filaments is 12,000 or less (for example, in the range of 3,000 to 12,000) and the fineness of the carbon fiber strands 5 is 8,000 dtex or less (for example, in the range of 2,000 to 8,000 dtex).

[0057] In the above description, PAN-based carbon fibers are used as the carbon fibers, but pitch-based carbon fibers can be used in place of the PAN-based carbon fibers, in whole or in part. When pitch-based carbon fibers are used, the carbon fiber strands preferably have a carbon fiber filament count of 12,000 or less, preferably 3,000 to 6,000, and a fineness of 6,000 dtex or less, preferably 1,000 to 4,000 dtex. If the number of carbon fiber filaments exceeds 6,000 and the fineness exceeds 6,000 dtex, as described above, the carbon fiber strands become thicker and stronger, making it difficult to manufacture the mesh-like knitted structure 1 itself. This not only makes the intersections between the chain stitch yarn 2 and the warp and weft insertion yarns 5 and 3 thicker, resulting in a composite material 10 with significant irregularities after resin impregnation, but also makes it difficult to maintain high drapeability and stretchability.

[0058] In the above explanation, it has been explained that the mesh-like knitted structure 1 can use yarns made of carbon fiber strands for the chain stitch yarns 2 and the weft insert yarns 3 as well as the warp insert yarns, but it is not necessary for the mesh-like knitted structure 1 to be made entirely of carbon fiber, that is, it is not necessary for all of the chain stitch yarns 2 and the weft insert yarns 3 that make up the mesh-like knitted structure 1 to be made of carbon fiber strands, and depending on the properties required of the mesh-like fiber reinforced composite material, i.e., strength, weight, etc., one or more of the chain stitch yarns 2 and the weft insert yarns 3 can be replaced with other fibers. In other words, in the present invention, at least the warp insert yarns 5 are carbon fiber strands made of carbon fiber, and the remaining yarns, i.e., the chain stitch yarns 2 and the weft insert yarns 3, can be made of fibers other than carbon fiber.

[0059] In this embodiment, fibers other than carbon fibers used for the chain stitch yarn 2 and the weft insert yarn 3 include, for example, organic fibers such as polyester, polyamide, polyacrylonitrile, polyvinyl alcohol, and polyolefin fibers, and aramid fibers; metal fibers such as titanium fibers and steel fibers; and inorganic fibers such as glass fibers; either alone or in combination. The chain stitch yarn 2 made from such fibers typically has a fineness of 10 to 600 dtex, preferably 30 to 300 dtex. If the fineness exceeds 600 dtex, the yarn becomes thicker, resulting in thicker areas where the chain stitch yarn 2 intersects with the warp and weft insert yarns 5 and 3, resulting in a composite with significant irregularities after resin impregnation. Furthermore, it becomes difficult to maintain high drapeability and stretchability. Furthermore, the weft insertion yarns 3 typically have a fineness of 10 to 600 dtex, and typically 2 to 4 yarns are used in a single pair, with the total fineness of the weft insertion yarns 3 being in the range of 700 to 2500 dtex. By using a thick weft insertion yarn 3, for example, 500 dtex x 2 (total fineness 1000 dtex) to 500 dtex x 4 (total fineness 2000 dtex), it is possible to obtain a composite material with improved impact resistance after resin impregnation, without increasing the thickness of the areas where the chain stitch yarn 2 and the warp and weft insertion yarns 5, 3 intersect.

[0060] In addition, the reinforcing fiber weight per square meter of the mesh-like knitted structure 1 in this embodiment is preferably 100 to 700 g. When surface smoothness is required for the mesh-like fiber reinforced composite material 10, which is an FRP molding, a weight of 100 to 300 g / m is preferably used by using thin reinforcing fiber yarns. 2 When the mesh-shaped fiber reinforced composite material 10 is required to have good mechanical properties or when a thick mesh-shaped fiber reinforced composite material 10 is required, a thick reinforcing fiber yarn is used and the yarn density is 300 to 700 g / m 2 It is preferable that the basis weight is 100 g / m. 2 If the knitted fabric is less than 700 g / m, the chain stitches 2A will be large (mesh-like knitted structure 1), and the voids G will increase, resulting in large irregularities in the mesh-like fiber-reinforced composite material 10. 2 If this is the case, the crimping of the carbon fiber strands will increase due to the crossing of the chain stitch yarns 2, 2 with each other and with the vertical and horizontal insertion yarns 5, 3, and stress concentration will undesirably reduce the mechanical properties of the mesh-shaped fiber reinforced composite material 10.

[0061] In the mesh-like fiber-reinforced composite material 10 using the mesh-like knitted structure 1 of this embodiment, when an impact force is applied, the impact energy is first absorbed by the front knitted structure 20a and the back knitted structure 20b of the knitted structure 20 (20a, 20b) into which the vertical insertion yarns 5 are inserted, and the impact force is alleviated.As a result, unlike the composite material using the fiber sheet 1B described in Patent Document 4 (Patent Publication No. 4463657) described above with reference to Figures 22 and 23, no large load is applied to the carbon fibers 50, which are straightly arranged unidirectional materials, and the carbon fibers are prevented from breaking, resulting in an FRP molded product with high impact resistance.

[0062] Furthermore, the mesh-like knitted structure 1A used in the mesh-like fiber-reinforced composite material 10A described in Patent Document 3 (Japanese Patent No. 6362454) shown in Figures 21(a) and (b) has excellent stretchability and drapeability, as described above, and is excellent in terms of formability into curved shapes. However, because of its stretchability, when it is used in a mesh-like fiber-reinforced composite material that has been impregnated with resin and hardened, i.e., when it is made into an FRP structure, there is a problem in that it can break from the resin with a slight external force.

[0063] To further improve the impact resistance of the FRP in the mesh-shaped fiber-reinforced composite material 10 of the present invention, it is preferable to use a resin with high breaking elongation so as to increase the impact energy absorbed in the resin portion. Preferred thermoplastic resins include thermoplastic epoxy resin, phenoxy resin, polycarbonate resin, polyester resin, polyurethane resin, polyamide resin, polyetherimide resin, and polyether ether ketone resin, while preferred thermosetting resins are high-breaking elongation resins with a breaking elongation of 4% or more, such as room-temperature curing or thermosetting epoxy resin, vinyl ester resin, MMA resin, acrylic resin, unsaturated polyester resin, and phenolic resin.

[0064] A thermoplastic epoxy resin is a linear polymer exhibiting thermoplasticity that is produced by chain extension of a bifunctional epoxy compound and a bifunctional phenolic compound through addition polymerization accompanied by ring-opening of the epoxy ring. For example, it can be obtained by blending bisphenol A epoxy resin and bisphenol A in a functional group ratio of 1:1 and polymerizing the mixture in situ in the presence of a phosphorus-based polymerization catalyst.

[0065] The mesh-like knitted structure 1 can be suitably produced using a Russell knitting machine, particularly by adopting the method for producing a sheet-like carbon fiber knitted fabric described in Patent Document 2 (Japanese Patent No. 4822528), and can also be knitted using a tricot knitting machine, a crochet knitting machine, etc. Such knitted fabric production methods are well known to those skilled in the art, and therefore further detailed explanations will be omitted.

[0066] (Opening ratio) In the present invention, the opening rate of the mesh-like fiber-reinforced composite material 10 produced using the above-mentioned mesh-like knitted structure 1 is important, and as will be described in detail later, the opening rate is 20 to 60%, preferably 20 to 50%, and more preferably 30 to 50%.

[0067] According to the present invention, the mesh-like knitted structure 1 is impregnated with resin R only into the knitted structure 20 formed by the chain stitch yarn 2 and the warp and weft insertion yarns 5, 3 in the mesh-like knitted structure 1, and then hardened.In other words, the resin is not filled into the voids G in the mesh-like knitted structure 1, so the opening rate of the mesh-like fiber-reinforced composite material 10 is substantially the same as the opening rate of the mesh-like knitted structure 1.

[0068] The open area ratio generally refers to the rate at which holes are formed in a plane, such as in mesh fabrics used in screen printing or punched metal. Similarly, in the present invention, the open area ratio of the mesh knitted structure 1 refers to the rate at which holes are formed in a plane of the mesh knitted structure 1. The mesh knitted structure 1 is scanned using a two-dimensional scanner, and the ratio of the areas with and without fibers is calculated. In practice, the mesh knitted structure 1 is scanned using a two-dimensional scanner, and the open area ratio is calculated by dividing it into void areas and fiber areas using image software. For example, such an open area ratio can be efficiently determined using a two-dimensional scanner manufactured by Canon Inc. (trade name: "CanoScan4400F"). Opening rate (%) = {(area of voids) / (area of fiber + area of voids)} x 100

[0069] As described above, in the present invention, the opening ratio of the mesh-like knitted structure 1 is set to 20 to 60%. If the opening ratio is less than 20%, the rigidity is very good, but the holes do not open after molding, the breathability is poor, and the structure becomes very heavy. If the opening ratio exceeds 60%, the breathability is very good and the structure is lightweight, but the amount of reinforcing fibers as a whole is insufficient, resulting in insufficient rigidity. The opening ratio is preferably set to 20 to 50%, and more preferably 30 to 50%.

[0070] In the present invention, the size of each opening (hole) in the mesh-like knitted structure 1 is also important, and the area of each opening is 1.5 to 80 mm 2 It is important that the opening area of each piece is 1.5mm 2 If it is less than this, there is a possibility that the hole will not be drilled during molding, and the opening area will be 80 mm 2If the mesh size exceeds this value, the mesh after molding may become too large, and the mesh-like fiber-reinforced composite material 10 may lose its rigidity.

[0071] (Impregnated resin) In the present invention, after or before shaping the mesh-like knitted structure 1 into a predetermined shape, only the knitted texture 20 and the warp and weft insertion yarns 5, 3 in the mesh-like knitted structure 1 are impregnated with resin R and hardened to form a mesh-like fiber-reinforced composite material 10. The fiber content in the mesh-like fiber-reinforced composite material 10 is 30 to 70%, preferably 40 to 70%, by weight of fiber.

[0072] In the above examples, examples of thermoplastic resins include thermoplastic epoxy resin, phenoxy resin, polycarbonate resin, polyester resin, polyurethane resin, polyamide resin, polyetherimide resin, and polyether ether ketone resin, and examples of thermosetting resins include room temperature curing or thermosetting epoxy resin, vinyl ester resin, MMA resin, acrylic resin, unsaturated polyester resin, and phenolic resin. However, it is preferable to use a thermoplastic resin, more preferably a thermoplastic resin with a breaking elongation of 4% or more, even more preferably a thermoplastic resin with a breaking elongation of 10% or more, and most preferably a thermoplastic resin with a breaking elongation of 50% or more.

[0073] (Molding method) Next, a method for molding the mesh-shaped fiber-reinforced composite material 10 according to the present invention will be described.

[0074] The mesh-shaped fiber reinforced composite material 10 can be formed using the same molding methods as those used for conventionally known fiber reinforced composite materials, such as press molding, sheet winding molding, tape winding molding, and hand bending molding.

[0075] 18(a) to 18(e) show a press molding method, which is one example of a molding method. In this press molding method, a mesh-like knitted structure 1 is fitted to a convex male mold 201, and by pressing, the mesh-like knitted structure 1 is molded to imitate the male mold 201 (FIG. 18(a)). At this time, the mesh-like knitted structure 1 produced according to the present invention has good drapeability, stretchability, good moldability, and is easy to work with, as described above.

[0076] Next, resin R is applied to the mesh-like knitted structure 1 using an impregnation brush or the like so that the resin is impregnated only into the knitted structure 20 (20a, 20b) consisting of the chain stitch yarns 2 (2a, 2b) of the mesh-like knitted structure 1 and the warp and weft insertion yarns 5, 3 (FIG. 18(b)). The resin R may be a thermosetting resin or a thermoplastic resin. Thereafter, a concave female mold 202 is placed on the male mold 201, and the resin is hardened by applying a predetermined pressure and heating, thereby forming a mesh-like fiber-reinforced composite material 10 shaped into a predetermined shape (FIG. 18(c)). The mesh-like fiber-reinforced composite material 10 is removed from the mold (FIG. 18(d)) and finished into the predetermined shape (FIG. 18(e)).

[0077] 19(a) and (b) show a vacuum forming method, which is another example of a molding method. According to this vacuum forming method, the mesh-like knitted structure 1 is formed by impregnating only the knitted structure 20 consisting of chain stitch yarns 2 and the warp and weft insertion yarns 5, 3 with resin and hardening it to form a flat mesh-like knitted structure 1a made of FRP material. Although thermosetting resins can also be used in a B-stage state, thermoplastic resins are preferably used. The mesh-like knitted structure 1 may be impregnated with resin in advance or immediately before molding.

[0078] The mesh-like knitted structure 1, which has been impregnated with and cured with resin, is placed on a concave vacuum mold (female mold) 202 as a mesh-like fiber-reinforced composite molding material 1a and is further covered with a resin film 60 (FIG. 19(a)). A vacuum is drawn into the female mold 202, and a male mold 201 is pressed against the female mold 202 from the resin film 60 side with a predetermined pressing force and heated. As a result, the resin that has impregnated and cured the mesh-like knitted structure 1a softens (melts) and is molded to conform to the female mold 202. The molding mold is cooled, yielding a mesh-like fiber-reinforced composite 10 shaped to a predetermined shape (FIG. 19(b)). Thereafter, as in the press molding method, the mesh-like fiber-reinforced composite 10 is removed from the mold and finished to a predetermined shape as shown in FIGS. 18(d) and (e).

[0079] In this vacuum molding method, when the resin is softened or melted, the mesh-like knitted structure 1a It has good drapeability, stretchability, and moldability, and can be molded to follow the male mold, making it easy to work with.

[0080] According to the vacuum molding method, the mesh-like knitted structure 1, which has been pre-impregnated with resin and hardened, can be used like a prepreg as the mesh-like fiber-reinforced composite molding material 1a, which has the advantages of good productivity, the holes in the mesh-like knitted structure 1 are not crushed during molding, and the sheet thickness does not become thin during molding, resulting in a composite with a thick cross-section, making it easier to achieve high strength.

[0081] Example 2 Another embodiment of the mesh-shaped fiber-reinforced composite material 10 according to the present invention will be described with reference to Figs. 7 and 8. Fig. 7 shows the mesh-shaped fiber-reinforced composite material 10 according to this embodiment. Used in FIG. 8 is a partially enlarged knitting structure diagram for explaining a mesh-like knitted structure, i.e., a mesh-like fiber sheet 1, which is a sheet-like reinforcing fiber knitted fabric, i.e., a sheet-like reinforcing fiber warp knitted fabric, and FIG. 9 is a diagram showing the structure of the mesh-like knitted structure of this embodiment.

[0082] The mesh-shaped fiber-reinforced composite material 10 of this embodiment is produced by impregnating each constituent yarn of the mesh-shaped knitted structure 1 shown in Figure 7 with resin R and curing it, in the same manner as described in Example 1, with reference to Figures 2(a) and (b).

[0083] As described in Example 1, the mesh-like knitted structure 1 of this example has a plurality of knitted structures 20, namely, a double vertical knitted structure 20 (20a, 20b) of a front side knitted structure 20a and a back side knitted structure 20b, which are made by knitting chain stitch yarns 2 (2a, 2b) in a loop shape in the vertical direction, alternating between the front and back sides of the knitted fabric to form chain stitches 2A, i.e., double chain stitches 2A (2Aa, 2Ab) of a front side chain stitch 2Aa and a back side chain stitch 2Ab, as well as a vertical insertion yarn 5 inserted into one needle in the front side knitted structure 20a and the back side knitted structure 20b of the knitted structure 20 (20a, 20b).

[0084] Here, as shown in Figures 1 and 4 to 6, the mesh-like knitted structure 1 of Example 1 is configured so that the horizontal insertion yarns 3 forming the horizontal insertion structure are inserted horizontally, for example, by two, three, or four needles, relative to the vertical knitted structure 20, and adjacent knitted structures 20 are bound together to form a sheet.

[0085] In contrast to this, in this Example 2, as shown in Figures 7 and 8, the weft insert yarns 3 (3a, 3b) are arranged in the horizontal direction (in this Example, they are inserted and arranged with three needles, but they can also be inserted and arranged with two or four needles) with respect to the vertical knitting structure 20, and the two or four weft insert yarns 3 are separated into weft insert yarns 3a and 3b, which are separated in front and behind the vertical insert yarn 5 and are arranged on the front and back sides of the knitted fabric as front side insert yarn 3a and back side insert yarn 3b, respectively. The mesh-like knitted structure 1 of this Example 2 is characterized in that the front and back of the knitted fabric are the same (mirror symmetry).

[0086] Also in this Example 2, at least the warp insert yarns 5 use carbon fiber strands made of carbon fiber as the reinforcing fiber. The chain stitch yarns 2 and the weft insert yarns 3 (3a, 3b) can be carbon fiber strands made of carbon fiber as the reinforcing fiber, just like the warp insert yarns 5, but other reinforcing fibers can also be used. These reinforcing fibers are as explained in Example 1, and will not be explained again here.

[0087] After or before shaping the mesh-like knitted structure 1 into a predetermined shape, as described above in Example 1, resin R is impregnated only into the knitted structure 20 (20a, 20b) consisting of chain stitch yarns 2 (2a, 2b), the vertical insertion yarns 5, and the horizontal insertion yarns 3 (3a, 3b) in the mesh-like knitted structure 1.

[0088] The mesh-shaped fiber-reinforced composite material 10 of Example 2 can also achieve the same effects as the mesh-shaped fiber-reinforced composite material 10 of Example 1. That is, as understood above, the mesh-shaped fiber-reinforced composite material 10 of Example 2 formed as described above has a carbon fiber yarn inserted vertically per needle, thereby increasing the longitudinal strength and elastic modulus. Furthermore, the chain stitch yarns 2 (2a, 2b) forming the stitches and the two or four aligned two-, three-, or four-needle weft-inserted yarns 3 (3a, 3b) located on both sides of the knitted fabric act as cushioning materials for the carbon fiber yarn of the one-needle vertically inserted yarn 5, improving impact resistance. Furthermore, even if stretchability is suppressed by the insertion of the one-needle vertically inserted yarn 5 or by increasing the fineness of the weft-inserted yarns 3 (3a, 3b), the mesh structure is easily shear-deformable, so it is easy to mold (shape) into three-dimensional shapes such as hemispheres.

[0089] Example 3 Another embodiment of the mesh-shaped fiber reinforced composite material 10 according to the present invention will be described with reference to Figs. 9 and 10. Fig. 9 shows the mesh-shaped fiber reinforced composite material 10 according to this embodiment. Used in FIG. 10 is a partially enlarged knitting structure diagram for explaining a mesh-like knitted structure, i.e., a mesh-like fiber sheet 1, which is a sheet-like reinforcing fiber knitted fabric, i.e., a sheet-like reinforcing fiber warp knitted fabric, and FIG. 11 is a diagram showing the structure of the mesh-like knitted structure 1 of this embodiment.

[0090] The mesh-shaped fiber-reinforced composite material 10 of this embodiment is produced by impregnating each constituent yarn of the mesh-shaped knitted structure shown in Figure 9 with resin R and curing it, in the same manner as described in Example 1, with reference to Figures 2(a) and (b).

[0091] As shown in Figure 9, the mesh-like knitted structure 1 of this embodiment, as described in Example 1, has a plurality of knitted structures 20, namely, a double vertical knitted structure 20 (20a, 20b) of a front side knitted structure 20a and a back side knitted structure 20b, which are produced by knitting chain stitches 2 (2a, 2b) in a loop-like manner in the vertical direction, alternating between the front and back sides of the knitted fabric to form double chain stitches 2A (2Aa, 2Ab) of a front side chain stitch 2Aa and a back side chain stitch 2Ab, and a vertical insertion yarn 5 inserted into one needle in the front side knitted structure 20a and the back side knitted structure 20b of the knitted structure 20 (20a, 20b).

[0092] Here, as shown in Figures 1 and 4 to 6, the mesh-like knitted structure 1 of Example 1 is configured so that the horizontal insertion yarns 3 forming the horizontal insertion structure are inserted horizontally, for example, by two, three, or four needles, relative to the vertical knitted structure 20, and adjacent knitted structures 20 are bound together to form a sheet.

[0093] In contrast, in Example 3, as shown in Figures 9 and 10, the weft insertion yarns 3 are arranged linearly in the transverse direction relative to the vertical knitting structure 20. In Example 3, the weft insertion yarns 3, together with the vertical insertion yarns 5, use carbon fiber strands made of carbon fiber as reinforcing fibers. The chain stitch yarns 2 (2a, 2b) can be carbon fiber strands made of carbon fiber as reinforcing fibers, like the weft insertion yarns 3 and the vertical insertion yarns 5, but other reinforcing fibers can also be used. These reinforcing fibers are as explained in Example 1, and will not be explained again here.

[0094] After or before shaping the mesh-like knitted structure 1 into a predetermined shape, as described above in Example 1, resin R is impregnated only into the knitted structure 20 (20a, 20b) consisting of chain stitch yarns 2 (2a, 2b), the vertical insertion yarns 5, and the horizontal insertion yarns 3 in the mesh-like knitted structure 1.

[0095] In the mesh-shaped fiber-reinforced composite material 10 of Example 3, the carbon fiber thread is inserted vertically with one needle and linearly in the horizontal direction, so the strength and elastic modulus are increased in both the vertical and horizontal directions. On the other hand, the shapeability is slightly inferior to that of Examples 1 and 2 above, but the mesh structure provides shear strength, and there are no problems with formability (shapeability) into three-dimensional shapes such as hemispheres.

[0096] (Experimental Examples 1 to 9, Comparative Examples 1 to 5) Next, to verify the effects of the mesh-like fiber-reinforced composite material 10 and mesh-like knitted structure 1 according to the present invention, fabrics were knitted by changing the types and opening ratios of the chain stitch yarns 2, warp insertion yarns 5, and weft insertion yarns 3 of the mesh-like knitted structure 1, and then the fabrics were impregnated with resin and molded to produce mesh-like fiber-reinforced composite materials 10, which were then evaluated in various ways. The experimental results are shown in Table 1. In the experimental examples and comparative examples, the fiber content in the composite material was 65% by weight.

[0097] Experimental Example 1 As shown in the mesh-like knitting structure and knitting structure diagram of Example 1 described with reference to Figures 1 to 3, a Karl Mayer HDR8EH-S 6-gauge double Russell warp knitting machine was used, and chain stitches 2A were formed alternately on the front and back sides of the chain stitch structure 20 using Kuraray Co., Ltd.'s Vinylon 500T-200 (fineness: 500 dtex) as the chain stitch yarn 2. At the same time, Mitsubishi Chemical Co., Ltd.'s carbon fiber yarn TR50S-12L-AL (fineness: 8000 dtex) was used as the single-needle warp insert yarn 5, and the Vinylon 500T-200 used as the chain stitch yarn 2 was used as the three-needle weft insert yarn 3. These two yarns were aligned to have a total fineness of 1000 dtex and supplied to each guide hole of the knitting machine, and knitted to a width of 40 cm with a course density of 9.5 stitches / 25.4 mm.

[0098] The knitted fabric obtained had a basis weight (actual mass) of 372 g / m 2 The thickness is 1.50 mm, the aperture ratio is 43.8%, and the area of each aperture (hole) is 4.96 mm 2 The knitted fabric had almost no stretch because carbon fiber yarns with a high tensile modulus were arranged in the length direction of the knitted fabric, but the mesh structure was easily stretched in diagonal directions.

[0099] Next, the knitted fabric was impregnated with a thermoplastic epoxy resin (manufactured by Nagase ChemteX Corporation, product name "XNR6850V"), and then the solvent was dried in an oven at 120°C for 10 minutes, and then heated at 160°C for 30 minutes to obtain a flat plate.

[0100] The mesh-like fiber-reinforced composite material 10 was subjected to a punching impact strength test (drop mass: 1.59 kg, drop height: 580 mm, striker: 20 mm hemispherical) using an Instron universal testing machine "CEAST9310." The load cell capacity was 10 kN (maximum design limit 5 kN), and the impact energy (potential energy) was 9.03 J. The results are shown in Table 1. In Table 1, "Peak Force" is the maximum load in the impact test, and "Total Energy" is the area under the displacement-load curve in the impact test. "Peak Force / design mass" is the maximum load per unit mass, and the larger this value, the more impact-resistant the structure is.

[0101] In addition, flat test pieces of the mesh-like fiber reinforced composite material 10 were prepared with the long sides in the vertical or horizontal direction, with the vertical (vertical, 0°) direction being defined as the case where the auxiliary threads (warp / chain knit) of the mesh-like fiber reinforced composite material 10 are aligned in the longitudinal direction of the test piece, and the horizontal (horizontal, 90°) direction being defined as the case where the auxiliary threads are aligned in the width direction of the test piece, and the tensile strength was measured using a universal testing machine "RTF-2410" manufactured by AND Co., Ltd. in accordance with JIS K 7164 (Test method for tensile properties of plastics).

[0102] Experimental Example 2 In Experimental Example 1, two weft insertion yarns 3a and 3b, which were made of aligned vinylon 500T-200 and supplied as three-needle weft insertion yarns 3, were inserted separately so that one was positioned above and one was positioned above the carbon fiber yarn inserted vertically through one needle in the thickness direction of the knitted fabric, as shown in the mesh-like knitting structure and knitting structure diagram shown in Example 2 described with reference to Figures 7 and 8. Knitting was carried out under the same conditions as in Experimental Example 1.

[0103] The resulting knitted fabric had a basis weight of 426 g / m 2 The thickness is 1.58 mm, the aperture ratio is 44.1%, and the area of each aperture (hole) is 5.00 mm 2 As in Experimental Example 1, the knitted fabric had almost no stretch in the length direction of the knitted fabric, but had a mesh structure that easily stretched in diagonal directions.

[0104] Next, a mesh-like fiber-reinforced composite material 10 was produced in the same manner as in Experimental Example 1, and a punching impact strength test was carried out. The results are shown in Table 1.

[0105] Experimental Example 3 In Experimental Example 1, two insert yarns of Vinylon 500T-200 were paralleled and supplied as the three-needle weft insert yarn 3, but this was increased to four, and the yarns were paralleled and supplied to a total fineness of 2000 dtex, and knitting was carried out under the same conditions as in Experimental Example 1.

[0106] The resulting knitted fabric had a basis weight of 445 g / m 2 The thickness is 1.82 mm, the aperture ratio is 24.8%, and the area of each aperture (hole) is 2.78 mm 2 As in Experimental Examples 1 and 2, the knitted fabric had almost no stretch in the length direction of the knitted fabric, but had a mesh structure that easily stretched in diagonal directions.

[0107] Next, a mesh-like fiber-reinforced composite material 10 was produced in the same manner as in Experimental Example 1, and a punching impact strength test was carried out. The results are shown in Table 1.

[0108] Experimental Example 4 In Experimental Example 3, the Vinylon 500T-200 yarn used for the chain stitch yarn 2 and the four aligned three-needle swing weft inserted yarns 3 was changed to polyester filament yarn PET560T-96-P703B (fineness: 560 dtex) manufactured by Teijin Ltd. (total fineness of weft inserted yarns: 2240 dtex), except that the yarn was knitted under the same conditions as Experimental Example 3.

[0109] The resulting knitted fabric had a basis weight of 507 g / m 2 The thickness is 1.70 mm, the aperture ratio is 26.0%, and the area of each aperture (hole) is 2.91 mm 2 As in Experimental Examples 1 and 2, the knitted fabric had almost no stretch in the length direction of the knitted fabric, but had a mesh structure that easily stretched in diagonal directions.

[0110] Next, a mesh-like fiber-reinforced composite material 10 was produced in the same manner as in Experimental Example 1, and a punching impact strength test was carried out. The results are shown in Table 1.

[0111] Experimental Example 5 In Experimental Example 2, two vinylon 500T-200 yarns, 3a and 3b, were inserted horizontally in three swing needles above and below the carbon fiber yarn inserted vertically in one swing needle, and two of each yarn were pulled together to increase the total to four yarns (total fineness of the weft-inserted yarns: 2000 dtex). The knitting was carried out under the same conditions as in Experimental Example 2.

[0112] The resulting knitted fabric had a basis weight of 483 g / m 2 The thickness is 1.70 mm, the aperture ratio is 25.2%, and the area of each aperture (hole) is 2.82 mm 2 As in Experimental Examples 1 and 2, the knitted fabric had almost no stretch in the length direction of the knitted fabric, but had a mesh structure that easily stretched in diagonal directions.

[0113] Next, a mesh-like fiber-reinforced composite material 10 was produced in the same manner as in Experimental Example 1, and a punching impact strength test was carried out. The results are shown in Table 1.

[0114] Experimental Example 6 The knitting was carried out under the same conditions as in Experimental Example 5, except that the chain stitch yarn 2 used in Experimental Example 5 and the two vinylon 500T-200 yarns used as the weft-inserted yarns 3a and 3b inserted horizontally through three swing needles were replaced with polyester filament yarn PET560T-96-P703B (fineness: 560 dtex) (total fineness of the weft-inserted yarns: 2240 dtex).

[0115] The resulting knitted fabric had a basis weight of 533 g / m 2 The thickness is 1.65mm, the aperture ratio is 26.2%, and the area of each aperture (hole) is 2.94mm 2 As in Experimental Example 5, the knitted fabric had almost no stretch in the length direction of the knitted fabric, but had a mesh structure that easily stretched in diagonal directions.

[0116] Next, a mesh-like fiber-reinforced composite material 10 was produced in the same manner as in Experimental Example 1, and a punching impact strength test was carried out. The results are shown in Table 1.

[0117] Experimental Example 7 Knitting was carried out under the same conditions as in Experimental Example 1, except that the course density, which was the knitting requirement of Experimental Example 1, of 9.5 threads / 25.4 mm was increased to 15.0 threads / 25.4 mm.

[0118] The resulting knitted fabric had a basis weight of 426 g / m 2 The thickness is 1.85 mm, the aperture ratio is 21.1%, and the area of each aperture (hole) is 1.52 mm 2 The mesh structure had a lower diagonal stretchability than the knitted fabric of Experimental Example 1 due to an increased course density and a reduced opening area.

[0119] Next, a mesh-like fiber-reinforced composite material 10 was produced in the same manner as in Experimental Example 1, and a punching impact strength test was carried out. The results are shown in Table 1.

[0120] Experimental Example 8 As shown in the mesh-like knit structure and knitting structure diagram shown in Example 3 described with reference to Figures 9 and 10, polyester filament yarn PET560T-96-P703B (fineness: 560 dtex) was used as chain stitch yarn 2, and chain stitches 2A were formed alternately on the front and back sides of the chain stitch structure 20 in the same manner as in Experimental Example 1. At the same time, carbon fiber yarn TR50S-12L-AL (fineness: 8000 dtex) manufactured by Mitsubishi Chemical Corporation was used as the one-needle warp insertion yarn 5, and the same carbon fiber yarn as used for the one-needle warp insertion yarn 5 was inserted linearly as the weft insertion yarn 3 between the front and back stitches for each course across the entire width in the width direction of the knitted fabric. As in Experimental Example 1, knitting was performed with a width of 40 cm and a course density of 9.5 stitches / 25.4 mm.

[0121] The resulting knitted fabric had a basis weight of 467 g / m 2 The thickness is 1.25 mm, the aperture ratio is 21.1%, and the area of each aperture (hole) is 2.39 mm 2 The mesh structure was such that continuous highly elastic carbon fiber threads were inserted in the length and width directions of the knitted fabric, so it was almost inelastic in both directions, but easily stretched in the diagonal direction.

[0122] Next, a mesh-like fiber-reinforced composite material 10 was produced in the same manner as in Experimental Example 1, and a punching impact strength test was carried out. The results are shown in Table 1.

[0123] Experimental Example 9 In Experimental Example 8, the carbon fiber yarn (laterally inserted yarn 3) inserted horizontally continuously in every course in the width direction was inserted every two courses (1 in 1 out), as shown in the knitting pattern of Figure 11, and other than this, knitting was performed under the same conditions as in Experimental Example 8.

[0124] The resulting knitted fabric had a basis weight of 471 g / m 2 The thickness is 1.57mm, the aperture ratio is 57.4%, and the area of each aperture (hole) is 6.5mm. 2 As with Experimental Example 8, the knitted fabric had almost no stretch in the length and width directions, but due to its large opening ratio, it had a mesh structure that was more likely to stretch in diagonal directions than the knitted fabric of Experimental Example 8.

[0125] Next, a mesh-like fiber-reinforced composite material 10 was produced in the same manner as in Experimental Example 1, and a punching impact strength test was carried out. The results are shown in Table 1.

[0126] Comparative Example 1 Comparative Example 1 is a knitted fabric similar to the mesh-shaped fiber-reinforced composite material described in the above Patent Document 3 (Japanese Patent No. 6362454), and is intended for comparison with the mesh-shaped fiber-reinforced composite material 10 of the present invention. In this comparative example, the same double Russell warp knitting machine used in the above experimental examples was used, and in the knitting structure and knitting texture diagrams shown in Figures 12 and 13, the chain stitch yarn 2 was vinylon 500T-200 (fineness: 500 dtex) used in Experimental Example 1, and the two-needle swing weft insertion yarn 3 was the carbon fiber yarn TR50S-12L-AL (fineness: 8000 dtex) used in Experimental Example 1, with the knitting width set to 40 cm and the course density set to 9.5 threads / 25.4 mm.

[0127] The resulting knitted fabric had a basis weight of 550 g / m 2 The thickness is 1.50 mm, the aperture ratio is 55.0%, and the area of each aperture (hole) is 6.04 mm 2 The knitted fabric had a mesh structure that was stretchable in both the length and width directions.

[0128] Next, a mesh-like fiber-reinforced composite material 10 was produced in the same manner as in Experimental Example 1, and a punching impact strength test was carried out. The results are shown in Table 1.

[0129] Comparative Example 2 In Comparative Example 2, the knitted fabric of Experimental Example 1 was knitted under the same conditions as Experimental Example 1, except that one vinylon 500T-200 (fineness: 500 dtex) was used as the weft insertion yarn 3 and the weft insertion structure was changed to a two-needle swing, as shown in Figure 14.

[0130] The resulting knitted fabric had a basis weight of 347 g / m 2 The thickness is 1.40 mm, the aperture ratio is 45.2%, and the area of each aperture (hole) is 5.03 mm 2 The knitted fabric had almost no stretch in the length direction, as with the knitted fabric of Experimental Example 1, but had a mesh structure that easily stretched in the width direction due to the two-needle swing horizontal insertion structure.

[0131] Next, a mesh-like fiber-reinforced composite material 10 was produced in the same manner as in Experimental Example 1, and a punching impact strength test was carried out. The results are shown in Table 1.

[0132] Comparative Example 3 The knitted fabric of Comparative Example 3 was knitted under the same conditions as the knitted fabric of Comparative Example 2, except that the carbon fiber yarn used as the one-needle warp insertion yarn 5 and the vinylon yarn used as the two-needle weft insertion yarn 3 were interchanged.

[0133] The weight of the resulting knitted fabric was 568 g / m 2 The thickness is 1.70 mm, the aperture ratio is 40.5%, and the area of each aperture (hole) is 4.85 mm 2 As with Comparative Example 2, the knitted fabric had almost no stretch in the length direction, just like the knitted fabric of Experimental Example 1, but because it was a two-needle swing horizontal insertion structure, it had a mesh structure that easily stretched in the width direction.

[0134] Next, a mesh-like fiber-reinforced composite material 10 was produced in the same manner as in Experimental Example 1, and a punching impact strength test was carried out. The results are shown in Table 1.

[0135] Comparative Example 4 The knitted fabric of Comparative Example 4 was knitted under the same conditions as Comparative Example 2, except that the swing width of the weft-insertion yarn 3 in the knitted fabric of Comparative Example 2 was changed from two-needle swing to three-needle swing, as shown in FIG.

[0136] The resulting knitted fabric had a basis weight of 324 g / m 2 The thickness is 1.35 mm, the aperture ratio is 51.3%, and the area of each aperture (hole) is 5.70 mm 2 The carbon fiber was inserted vertically in the length direction of the knitted fabric with one needle swing, so there was almost no stretch, as in Comparative Example 2, and the mesh structure stretched slightly in the width direction.

[0137] Next, a mesh-like fiber-reinforced composite material 10 was produced in the same manner as in Experimental Example 1, and a punching impact strength test was carried out. The results are shown in Table 1.

[0138] Comparative Example 5 The knitted fabric of Comparative Example 5 had the mesh-like knitting structure and knitting structure diagram shown in Figs. 16 and 17, and was knitted under the same conditions as Comparative Example 2 except that the swing width was changed to four needles.

[0139] The resulting knitted fabric had a basis weight of 339 g / m 2 , thickness is 1.45mm, aperture ratio is 40.6%, and the area of each aperture (hole) is 4.60mm 2 The mesh structure had less stretch in the width direction than the knitted fabric of Comparative Example 4 using the three-needle horizontal insertion yarn 3.

[0140] Next, a mesh-like fiber-reinforced composite material 10 was produced in the same manner as in Experimental Example 1, and a punching impact strength test was carried out. The results are shown in Table 1.

[0141] [Table 1]

[0142] (Consideration) The above experimental and comparative examples demonstrate that high tensile strength and impact strength can be imparted to a mesh knitted structure by inserting high-strength, high-elasticity carbon fiber yarns in the vertical or horizontal direction. This high impact strength is particularly evident because the continuously arranged carbon fibers respond quickly to impacts and absorb the impact energy. However, continuously arranged carbon fibers may be at a disadvantage in terms of formability because they are restricted in their movement during press molding. However, this is limited to cases where particularly high formability is required, and can be addressed by selecting the specifications of the knitted structure depending on the application.

[0143] On the other hand, it was confirmed that by placing thick knitted yarn or inserted yarn made of synthetic fiber around the carbon fiber yarn as a cushioning material, the carbon fiber is protected and a mesh-shaped fiber-reinforced composite material with high impact resistance can be obtained.

[0144] Furthermore, it was found from Experimental Examples 1 to 9 and Comparative Examples 2, 4, and 5 that by using thick fineness yarns for the weft-inserted yarns, the impact resistance after resin impregnation was improved. [Industrial Applicability]

[0145] The porous structure of the present invention is particularly suitable as an interior / exterior component for protectors such as protective helmets and prosthetic limbs (prosthetic legs and prosthetic hands), but its applications are not limited thereto. For example, it can be used in a wide range of industrial and consumer applications, including medical materials such as casts for immobilizing affected areas, clothing and equipment such as shoes and hats for sports and leisure, filters and housing components, reinforcing or protective components for pipes and hoses, and structural reinforcing components, as well as structural and decorative components for aircraft, rockets, artificial satellites, automobiles, motorcycles, trains, bicycles, houses, optical equipment, home appliances, and portable electronic devices, which require molding and processing into complex curved shapes while maintaining high rigidity. [Explanation of symbols]

[0146] 1. Mesh-like knitted structure 1a Mesh-shaped fiber-reinforced composite molding material 2(2a, 2b) Chain knitting yarn 2A chain stitch 3(3a, 3b) Horizontally inserted yarn 5 Vertical insertion threads 10 Mesh-like fiber-reinforced composite material 20 Knitting structure

Claims

1. The knitted structure has a mesh-like knitted structure formed by a plurality of vertical knitted structures produced by knitting chain stitches while continuous chain stitch yarns are formed in the vertical direction, a vertical insertion yarn inserted into one needle in the vertical direction along the chain stitches, and a horizontal insertion yarn inserted horizontally into the vertical knitted structures to bind adjacent knitted structures together, A mesh-shaped fiber reinforced composite material in which only the knitting structure and the warp and weft insertion yarns in the mesh-shaped knitted structure are impregnated with a resin and hardened, At least the warp insert yarns of the chain stitch yarns and the warp and weft insert yarns are carbon fiber strands made of carbon fiber, The opening ratio of the mesh-like knitted structure is 20 to 60%. A mesh-like fiber-reinforced composite material characterized by:

2. The knitted structure has a mesh-like knitted structure formed by a plurality of vertical knitted structures produced by knitting chain stitches while continuous chain stitch yarns are formed in the vertical direction, a vertical insertion yarn inserted into one needle in the vertical direction along the chain stitches, and a horizontal insertion yarn inserted horizontally into the vertical knitted structures to bind adjacent knitted structures together, A mesh-shaped fiber reinforced composite material obtained by forming the mesh-shaped knitted structure into a predetermined shape, and then impregnating only the knitting structure and the warp and weft insertion yarns in the mesh-shaped knitted structure with a resin and hardening the resin, At least the warp insert yarns of the chain stitch yarns and the warp and weft insert yarns are carbon fiber strands made of carbon fiber, The opening ratio of the mesh-like knitted structure is 20 to 60%. A mesh-like fiber-reinforced composite material characterized by:

3. 3. The mesh-shaped fiber-reinforced composite material according to claim 1 or 2, characterized in that the resin impregnated into the mesh-shaped knitted structure is a thermoplastic resin such as a thermoplastic epoxy resin, a phenoxy resin, a polycarbonate resin, a polyester resin, a polyurethane resin, a polyamide resin, a polyetherimide resin, or a polyether ether ketone resin; or a thermosetting resin such as a room temperature curing or thermosetting epoxy resin, a vinyl ester resin, an MMA resin, an acrylic resin, an unsaturated polyester resin, or a phenolic resin.

4. The knitted structure has a mesh-like knitted structure formed by a plurality of vertical knitted structures produced by knitting chain stitches while continuous chain stitch yarns are formed in the vertical direction, a vertical insertion yarn inserted into one needle in the vertical direction along the chain stitches, and a horizontal insertion yarn inserted horizontally into the vertical knitted structures to bind adjacent knitted structures together, A mesh-shaped fiber reinforced composite material in which only the knitted structure and the warp and weft insertion yarns in the mesh-shaped knitted structure are impregnated with a resin, hardened, and then shaped into a predetermined shape, At least the warp insert yarns of the chain stitch yarns and the warp and weft insert yarns are carbon fiber strands made of carbon fiber, The opening ratio of the mesh-like knitted structure is 20 to 60%. A mesh-like fiber-reinforced composite material characterized by:

5. 5. The mesh-shaped fiber-reinforced composite material according to claim 4, wherein the resin impregnated into the mesh-shaped knitted structure is a thermoplastic resin such as a thermoplastic epoxy resin, a phenoxy resin, a polycarbonate resin, a polyester resin, a polyurethane resin, a polyamide resin, a polyetherimide resin, or a polyether ether ketone resin.

6. The mesh-like fiber-reinforced composite material according to any one of claims 1 to 5, characterized in that the weft-inserted yarns are arranged by inserting two, three, or four needles in the horizontal direction relative to the vertical knitting structure.

7. The horizontally inserted yarn is arranged by inserting two, three, or four needles horizontally into the vertical knitting structure, and is arranged on the front and back of the knitted fabric, separated in front and behind the vertically inserted yarn. A mesh-like fiber-reinforced composite material described in any one of claims 1 to 5.

8. 8. The mesh-like fiber-reinforced composite material according to claim 6, wherein the weft insertion yarns are knitted into the knitted structure in the vertical direction at regular intervals.

9. The mesh-like fiber-reinforced composite material according to any one of claims 1 to 8, characterized in that the chain stitch yarns and the weft insertion yarns are yarns made from organic fibers such as polyester-based, polyamide-based, polyacrylonitrile-based, polyvinyl alcohol-based, and polyolefin-based fibers, and aramid fibers; metal fibers such as titanium fibers and steel fibers; and inorganic fibers such as carbon fibers and glass fibers, either alone or in combination.

10. The mesh-shaped fiber-reinforced composite material according to any one of claims 1 to 5, characterized in that the weft insertion yarns are arranged linearly in a transverse direction relative to the vertical knitting structure, and the weft insertion yarns are carbon fiber strands made of carbon fiber.

11. 11. The mesh-like fiber-reinforced composite material according to claim 1, wherein the chain stitch yarn has a fineness of 10 to 600 dtex.

12. The warp insertion yarns are (a) A carbon fiber strand of PAN-based carbon fiber having 24,000 or less carbon fiber filaments and a fineness of 16,000 dtex or less, or (b) A carbon fiber strand made of pitch-based carbon fiber having 12,000 or less carbon fiber filaments and a fineness of 6,000 dtex or less.

12. The mesh-like fiber-reinforced composite material according to claim 1.

13. The weft insertion yarn has a fineness of 10 to 600 dtex, and is used in a combination of 2 to 4 strands, with a total fineness of 700 to 2500 dtex. The mesh-like fiber reinforced composite material according to any one of claims 1 to 12.

14. The knitted structure has a mesh-like knitted structure formed by a plurality of vertical knitted structures produced by knitting chain stitches while continuous chain stitch yarns are formed in the vertical direction, a vertical insertion yarn inserted into one needle in the vertical direction along the chain stitches, and a horizontal insertion yarn inserted horizontally into the vertical knitted structures to bind adjacent knitted structures together, A mesh-shaped fiber-reinforced composite molding material in which only the knitting structure and the warp and weft insertion yarns in the mesh-shaped knitted structure are impregnated with resin.

15. A mesh-shaped fiber-reinforced composite molding obtained by shaping the mesh-shaped fiber-reinforced composite molding material according to claim 14.

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