Fiber structure and fiber reinforced composite material

Abstract

To provide a fiber structure and a fiber reinforced composite material, which can suppress yarn slippage in pultrusion of a single layer and suppress occurrence of dents on a molded article.SOLUTION: A fiber structure 10 is formed by repeatedly providing a unit structure 30 consisting of a plurality of first intersections 21 and a plurality of second intersections 22 in a first direction X and a second direction Y. The unit structure 30 consists of a first twill texture part 31 and a second twill texture part 32. The first twill texture part 31 constitutes 2 / 1 twill texture having two first intersections 21 and one second intersection 22 along a first yarn 11. The second twill texture part 32 constitutes 1 / 2 twill texture having one first intersection 21 and two second intersections along the first yarn 11.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a fiber structure and a fiber-reinforced composite material. [Background technology]

[0002] Fiber-reinforced composites are known as lightweight and high-strength materials and are produced by impregnating a fiber structure made of reinforcing fibers with a matrix material such as a resin and compounding the fiber structure.

[0003] For example, Patent Document 1 discloses a pultrusion molded product, which is a fiber-reinforced composite material, that has multiple woven fabric substrates, which are fiber structures. Each woven fabric substrate is made of warp and weft threads that cross each other. The pultrusion molded product is formed by stacking multiple woven fabric substrates, impregnating them with resin, and pulling them in the warp direction. In the woven fabric substrate, the weft threads arranged on the outermost surface of the woven fabric substrate laminate during pultrusion molding prevent the cured resin from remaining inside the mold, thereby suppressing the formation of dents in the pultrusion molded product. Weaves of 2 / 1 twill, 2 / 2 twill, satin, etc. are disclosed as weaves for the woven fabric substrate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-67557 Summary of the Invention [Problem to be solved by the invention]

[0005] Fiber-reinforced composite materials are sometimes produced using a single woven fabric substrate as a single-layer fiber structure. When a single-layer fiber structure is used as the woven fabric substrate, for example, in the fiber structures disclosed in Patent Document 1, which use a 2 / 1 twill or satin weave, the lengths of the weft threads passing over the warp threads are different on the front and back sides of the fiber structure. In other words, the front and back sides of the fiber structure are asymmetric. When a fiber-reinforced composite material is produced using a single-layer fiber structure, the asymmetric front and back sides of the fiber structure may create areas where the weft threads cannot scrape off the resin adhering to the inside of the mold during molding, which may result in the cured resin remaining inside the mold.

[0006] Among the fiber structures disclosed in Patent Document 1, those using a 2 / 2 twill weave allow the length of the weft threads passing over the warp threads to be the same on the front and back sides. In other words, using a 2 / 2 twill weave allows the front and back sides of the fiber structure to be symmetrical. However, in this case, the number of entanglements between the warp threads and the weft threads is reduced on both the front and back sides of the fiber structure compared to those using a 2 / 1 twill weave, which may cause misalignment during pultrusion molding. For these reasons, it is desirable for a fiber structure to suppress misalignment and prevent the occurrence of dents in the molded product due to retention of the cured resin inside the mold, even when used as a single layer as a substrate for pultrusion molding. [Means for solving the problem]

[0007] The fiber structure for solving the above-mentioned problems includes a plurality of first yarns extending in a first direction and arranged parallel to one another, and a plurality of second yarns extending in a second direction perpendicular to the first direction and arranged parallel to one another, the fiber structure having a first surface which is one surface in a third direction perpendicular to each of the first direction and the second direction, a second surface which is the other surface in the third direction, a plurality of first intersections where the first yarns and the second yarns are aligned in the third direction and the first yarns are located on the first surface and the second yarns are located on the second surface, and a plurality of first intersections where the first yarns and the second yarns are aligned in the third direction and the second yarns are located on the second surface. The present invention relates to a fiber structure that serves as a reinforcing base material for a fiber-reinforced composite material, and the fiber structure has a plurality of second intersections where a first yarn is located and the second yarn is located on the first surface, and a unit structure consisting of a plurality of the first intersections and a plurality of the second intersections is repeated a plurality of times in the first direction and the second direction, and the unit structure comprises a first twill weave portion that forms a 2 / 1 twill weave, having two of the first intersections and one of the second intersections along the first yarn, and a second twill weave portion that forms a 1 / 2 twill weave, having one of the first intersections and two of the second intersections along the first yarn.

[0008] According to this, the fiber structure has a unit structure as its smallest unit, and is formed by repeating the unit structure in each of the first and second directions. In the unit structure, the number of first intersections in the first twill weave portion is equal to the number of second intersections in the second twill weave portion. In a fiber structure having such a unit structure as its smallest unit, the distribution of each of the first intersections and second intersections formed on the first surface is also formed on the second surface. In other words, the fiber structure has the distribution of the first intersections and second intersections that is present on the first surface also on the second surface.

[0009] Furthermore, the plurality of first twill weave portions form a 2 / 1 twill weave, and the plurality of second twill weave portions form a 1 / 2 twill weave. In this case, the unit structure has a greater number of entanglements than when the unit structure has twill weave portions woven with, for example, a 2 / 2 twill, a 1 / 3 twill, or a 3 / 1 twill. Therefore, the above-mentioned fiber structure can have a greater number of entanglements in the unit structure while having the same structure on the first and second sides. In other words, when the fiber structure is used as a reinforcing substrate for a fiber-reinforced composite material produced by pultrusion molding, it can suppress misalignment associated with pultrusion molding.

[0010] Furthermore, since the multiple first twill weave portions form a 2 / 1 twill weave, each of the multiple first yarns included in the first twill weave portion forms a first intersection portion with the second yarn. In other words, in the fiber structure, the first twill weave portion has a portion where two first intersection portions are adjacent in the first direction. For example, consider a situation in which a fiber structure is used as a reinforcing substrate to produce a fiber-reinforced composite material by pultrusion molding. In this situation, when a single-layer fiber structure impregnated with a resin or the like is pulled out of a mold in the second direction, the portion crossing the unit structure serves as a claw portion on the first surface to pull out the fiber structure and scrape off the resin or the like adhering to the mold. The fiber structure has multiple claw portions on each of the first and second surfaces. The claw portions are portions where the first yarns are exposed to the outside of the fiber structure and where the exposed first yarns are aligned in the third direction with respect to two second yarns adjacent in the first direction. In other words, the claw portions on the first surface are formed by portions of the fiber structure where two first intersections are continuous in the first direction. The claw portions on the second surface are formed by portions of the fiber structure where two second intersections are continuous in the first direction. Because the front and back are symmetrical, the fiber structure can be scraped off resin by the claw portions on each of the first and second surfaces. This scraping can prevent the adhesion of resin, etc., to the mold, thereby preventing the occurrence of dents in the manufactured fiber-reinforced composite material due to the adhesion of resin, etc. As described above, the fiber structure can prevent misalignment and prevent the occurrence of dents in the fiber-reinforced composite material during single-layer pultrusion molding.

[0011] In the above fiber structure, each of the plurality of first intersections and each of the plurality of second intersections may be formed of a plurality of the first yarns and one of the second yarns. When two first intersections are arranged side by side in the first direction, the first yarn included in the first intersection is arranged side by side with two second yarns in the third direction, and the two second yarns are arranged side by side in the first direction. In this case, the two second yarns are slightly displaced toward each other in the first direction by the first yarn that crosses in the first direction.

[0012] Next, consider a case where three second threads are lined up in the first direction. Furthermore, consider a case where the central second thread of the three second threads is displaced toward one side of the other second threads by a first thread, while being displaced toward the other side of the other second threads by a first thread different from the first thread. In this case, the second thread extends in the second direction and meanders toward both one side and the other side of the first direction. The magnitude of the load caused by the meandering on the second thread increases as the wavelength of the meandering becomes shorter. This is because, when the wavelength of the meandering is short, the angle of bending of the second thread when meandering increases.

[0013] In the textile structure having the above configuration, each of the plurality of first intersections and each of the plurality of second intersections is composed of a plurality of first yarns and one second yarn. Therefore, the interval at which the meandering occurs in the second direction can be increased. This allows the wavelength of the meandering to be lengthened. As a result, the textile structure having the above configuration can reduce the meandering that occurs in the second yarn. As a result, the textile structure having the above configuration can reduce the load acting on the second yarn.

[0014] In the above fiber structure, the first twill weave portion and the second twill weave portion may be aligned in the first direction in the unit structure. For example, compared with a case where the first twill weave portion and the second twill weave portion are aligned only in the second direction in the unit structure, the above configuration can reduce the gaps at the locations where the first twill weave portion and the second twill weave portion are interchanged. As a result, when a fiber-reinforced composite material is produced by pultrusion molding using the fiber structure having the above configuration as a base material, accumulation of resin or the like in the gaps in the fiber structure can be suppressed.

[0015] The fiber-reinforced composite material for solving the above problem is a fiber-reinforced composite material formed by impregnating a fiber structure with a matrix material, and the fiber structure is the fiber structure described above.

[0016] According to this, when a fiber-reinforced composite material is produced by pultrusion molding using the fiber structure having the above configuration as a reinforcing substrate, the fiber-reinforced composite material can be produced while suppressing misalignment in the fiber structure. Furthermore, even when a single-layer fiber structure is used as a reinforcing substrate, the above configuration can suppress adhesion of the matrix material to the inner surface of the mold used to mold the fiber structure during pultrusion molding. In other words, the above configuration can suppress the occurrence of dents in the fiber-reinforced composite material. [Effects of the Invention]

[0017] According to the present invention, in single-layer pultrusion molding, it is possible to suppress misalignment and the occurrence of dents in the molded product. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a perspective view showing a fiber-reinforced composite material. [Figure 2] FIG. 2 is a diagram showing the first surface of the fiber structure. [Figure 3] FIG. 3 is a diagram showing the second surface of the fiber structure. [Figure 4] FIG. 4 is a cross-sectional view taken along line 4-4 in FIG. [Figure 5] FIG. 5 is a cross-sectional view taken along line 5-5 in FIG. [Figure 6] FIG. 6 is a schematic diagram showing a fiber structure, a fiber-reinforced composite material, and a pultrusion molding device. [Figure 7] FIG. 7 is a diagram showing a fiber structure. [Figure 8] FIG. 8 is a diagram showing a fiber structure. [Figure 9] FIG. 9 is a cross-sectional view taken along line 9-9 in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, one embodiment of a fiber structure and a fiber reinforced composite material will be described with reference to FIGS. <Fiber reinforced composite materials> As shown in Fig. 1, the fiber-reinforced composite material 100 is composed of a fiber structure 10 and a matrix resin 92a as a matrix material. The fiber-reinforced composite material 100 is produced by impregnating the fiber structure 10 with the matrix resin 92a. In other words, the fiber structure 10 is a reinforcing base material for the fiber-reinforced composite material 100. The matrix resin 92a is, for example, a thermosetting resin. Examples of thermosetting resins include epoxy resin, vinyl ester resin, unsaturated polyester resin, and phenolic resin.

[0020] <Fiber structure> The fiber structure 10 is composed of a plurality of first yarns 11 and a plurality of second yarns 12. For example, when the first yarns 11 are weft yarns, the second yarns 12 are warp yarns. Each of the first yarns 11 and the second yarns 12 is a reinforcing fiber. The reinforcing fiber is, for example, carbon fiber or glass fiber. The cross-sectional shape (not shown) of the first yarns 11 when viewed from the direction in which the main yarn axis of the first yarns 11 extends is circular. As shown in Figures 3 and 4, the cross-sectional shape of the second yarns 12 when viewed from the direction in which the main yarn axis of the second yarns 12 extends is flat. The cross-sectional area of ​​the second yarns 12 is larger than that of the first yarns 11.

[0021] 1, the first yarns 11 extend in a first direction X. In other words, the main yarn axis of the first yarns 11 extends in the first direction X. In the fiber structure 10, the multiple first yarns 11 are arranged parallel to one another.

[0022] The second yarns 12 extend in the second direction Y. In other words, the main yarn axis of the second yarns 12 extends in the second direction Y. The second direction Y is a direction perpendicular to the first direction X. In other words, the second yarns 12 extend in a direction perpendicular to the first yarns 11. The multiple second yarns 12 are arranged parallel to one another.

[0023] The fiber structure 10 has a flat plate shape with a thickness direction in a third direction Z, which is perpendicular to each of the first direction X and the second direction Y. The fiber structure 10 has a first surface 13 and a second surface 14 as end surfaces in the third direction Z. In other words, the fiber structure 10 has the first surface 13, which is one surface in the third direction Z, and the second surface 14, which is the other surface in the third direction Z.

[0024] The fiber structure 10 is a single layer. Each of the plurality of first yarns 11 constitutes both a first surface 13 and a second surface 14. Furthermore, each of the plurality of second yarns 12 constitutes both a first surface 13 and a second surface 14.

[0025] <First intersection and second intersection> 2 and 3 show a portion of the textile structure 10. As shown in FIGS. 2 and 3, the textile structure 10 has a plurality of first intersections 21. The first intersections 21 are portions of the textile structure 10 where the first yarns 11 and the second yarns 12 are aligned in the third direction Z such that the first yarns 11 are located on the first surface 13 and the second yarns 12 are located on the second surface 14. In other words, at the first intersections 21, the first yarns 11 are exposed to the outside of the textile structure 10 on the first surface 13. Furthermore, at the first intersections 21, the second yarns 12 are exposed to the outside of the textile structure 10 on the second surface 14.

[0026] In the fiber structure 10, the first intersections 21 are made up of four first yarns 11 and one second yarn 12. That is, each of the multiple first intersections 21 is made up of multiple first yarns 11 and one second yarn 12.

[0027] The textile structure 10 has a plurality of second intersections 22. The second intersections 22 are portions of the textile structure 10 where the first yarns 11 and the second yarns 12 are aligned in the third direction Z such that the first yarns 11 are located on the second surface 14 and the second yarns 12 are located on the first surface 13. In other words, at the second intersections 22, the first yarns 11 are exposed to the outside of the textile structure 10 on the second surface 14. Furthermore, at the second intersections 22, the second yarns 12 are exposed to the outside of the textile structure 10 on the first surface 13.

[0028] In the fiber structure 10, the second intersections 22 are made up of four first yarns 11 and one second yarn 12. That is, each of the multiple second intersections 22 is made up of multiple first yarns 11 and one second yarn 12.

[0029] <Claws and grooves> The textile structure 10 has a plurality of claw portions 23 on each of the first surface 13 and the second surface 14. The claw portions 23 are portions of the first yarns 11 exposed to the outside of the textile structure 10, and are portions of the exposed first yarns 11 aligned in the third direction Z with respect to two second yarns 12 adjacent to each other in the first direction X. In other words, the claw portions 23 on the first surface 13 are formed by portions of the textile structure 10 where two first intersection portions 21 are continuous in the first direction X. Furthermore, the claw portions 23 on the second surface 14 are formed by portions of the textile structure 10 where two second intersection portions 22 are continuous in the first direction X.

[0030] The fiber structure 10 has a plurality of grooves 24 on each of the first surface 13 and the second surface 14. The grooves 24 are portions of two second yarns 12 adjacent to each other in the first direction X that are exposed to the outside of the fiber structure 10. In other words, the grooves 24 on the first surface 13 are formed in portions of the fiber structure 10 where two second intersections 22 are continuous in the first direction X. Furthermore, the grooves 24 on the second surface 14 are formed in portions of the fiber structure 10 where two first intersections 21 are continuous in the first direction X.

[0031] In the fiber structure 10, the claw portions 23 and the groove portions 24 are aligned in the third direction Z. In other words, the portions of the fiber structure 10 where the claw portions 23 are formed on the first surface 13 form the groove portions 24 on the second surface 14. Furthermore, the portions of the fiber structure 10 where the claw portions 23 are formed on the second surface 14 form the groove portions 24 on the first surface 13.

[0032] <Unit structure> The fiber structure 10 is composed of a plurality of unit structures 30. In Fig. 2, the unit structures 30 are indicated by the two-dot chain line. Two unit structures 30 are shown in the range of the first surface 13 of the fiber structure 10 shown in Fig. 2.

[0033] The unit structure 30 is a part of the fiber structure 10. The unit structure 30 is made up of a plurality of first yarns 11 and a plurality of second yarns 12. The unit structure 30 also is made up of a plurality of first intersections 21 and a plurality of second intersections 22.

[0034] The fibrous structure 10 is formed by arranging a plurality of unit structures 30 in each of the first direction X and the second direction Y on each of the first surface 13 and the second surface 14. In the fibrous structure 10, a first end of each unit structure 30 in the first direction X is continuous with a second end in the first direction X of another unit structure 30 adjacent to the unit structure 30. In addition, in the fibrous structure 10, a first end of each unit structure 30 in the second direction Y is continuous with a first end in the second direction Y of another unit structure 30 adjacent to the unit structure 30. Therefore, the fibrous structure 10 is formed by repeating a plurality of unit structures 30 in the first direction X and the second direction Y. The unit structure 30 is the smallest repeating unit of the fibrous structure 10. In other words, each of the first surface 13 and the second surface 14 is formed by repeating the unit structures 30 in the first direction X and the second direction Y.

[0035] The unit structures 30 at both ends of the fiber structure 10 in the first direction X each have an end that is not continuous with another unit structure 30 in the first direction X. In addition, the unit structures 30 at both ends of the fiber structure 10 in the second direction Y each have an end that is not continuous with another unit structure 30 in the second direction Y.

[0036] <First twill weave section and second twill weave section> As shown in Fig. 2, the unit structure 30 is made up of a first twill weave portion 31 and a second twill weave portion 32. The unit structure 30 is made up of the first twill weave portion 31 and the second twill weave portion 32 aligned in the second direction Y. In other words, the first twill weave portion 31 and the second twill weave portion 32 are aligned in the second direction Y in the unit structure 30.

[0037] The first twill portion 31 is formed by a 2 / 1 twill weave of a plurality of first yarns 11 and a plurality of second yarns 12. Here, the 2 / 1 twill weave is a structure in which two first intersections 21 and one second intersection 22 are arranged side by side in the first direction X, and three of these structures are provided in the second direction Y, and the three second intersections 22 are not consecutive in the second direction Y.

[0038] The first twill weave portion 31 consists of six first intersection portions 21 and three second intersection portions 22. The first twill weave portion 31 consists of three types of first twill-forming portions 31a, 31b, and 31c. The three types of first twill-forming portions 31a, 31b, and 31c are arranged in the second direction Y in the following order: first twill-forming portion 31a, first twill-forming portion 31b, and first twill-forming portion 31c. The first twill weave portion 31 is formed by arranging the three types of first twill-forming portions 31a, 31b, and 31c in the second direction Y. Each of the first twill-forming portions 31a, 31b, and 31c is formed by four first yarns 11 and three second yarns 12. In other words, each of the first twill-forming portions 31a, 31b, and 31c is formed by arranging two first intersection portions 21 and one second intersection portion 22 in the first direction X. Each of the first twill-forming portions 31a, 31b, and 31c has two first intersections 21 and one second intersection 22 along the four first yarns 11. In other words, the first twill portion 31 forms a 2 / 1 twill design having two first intersections 21 and one second intersection 22 along the first yarns 11.

[0039] In the three types of first twill forming portions 31a, 31b, and 31c, the order in which the first intersection portions 21 and the second intersection portions 22 are arranged in the first direction X is different from one another. In other words, in the first twill weave portion 31, the position of the second intersection portion 22 in the first direction X is different from one another among the three types of first twill forming portions 31a, 31b, and 31c.

[0040] Each of the first intersections 21 in the first twill weave portion 31 forms a claw portion 23 on the first surface 13 of the fiber structure 10. Each of the first intersections 21 in the first twill weave portion 31 forms a groove portion 24 on the second surface 14 of the fiber structure 10. In other words, each of the first intersections 21 in the first twill weave portion 31 is adjacent to another first intersection 21 different from the first intersection 21 in the first direction X.

[0041] The second twill portion 32 is formed by a 1 / 2 twill weave of a plurality of first yarns 11 and a plurality of second yarns 12. Here, the 1 / 2 twill weave refers to a structure in which one first intersection portion 21 and two second intersection portions 22 are arranged side by side in the first direction X, and three of these structures are provided in the second direction Y, and the three first intersection portions 21 are not consecutive in the second direction Y.

[0042] The second twill weave portion 32 is made up of three first intersection portions 21 and six second intersection portions 22. The second twill weave portion 32 is made up of three types of second twill forming portions 32a, 32b, and 32c. The second twill weave portion 32 is formed by arranging the three types of second twill forming portions 32a, 32b, and 32c in the second direction Y. Each of the second twill forming portions 32a, 32b, and 32c is made up of four first yarns 11 and three second yarns 12. Each of the second twill forming portions 32a, 32b, and 32c is formed by arranging one first intersection portion 21 and two second intersection portions 22 in the first direction X. Each of the second twill forming portions 32a, 32b, and 32c has one first intersection portion 21 and two second intersection portions 22 along the four first yarns 11. In other words, the second twill portion 32 forms a ½ twill having one first intersection 21 and two second intersections 22 along the first yarn 11 .

[0043] In each of the three types of second twill-forming portions 32a, 32b, and 32c, the order in which the first intersection portions 21 and the second intersection portions 22 are arranged in the first direction X is different from one another. In other words, in the second twill weave portion 32, the position of the first intersection portion 21 in the first direction X is different among the three types of second twill-forming portions 32a, 32b, and 32c.

[0044] Each second intersection 22 in the second twill weave portion 32 forms a groove 24 on the first surface 13 of the fiber structure 10. Each second intersection 22 in the second twill weave portion 32 forms a claw 23 on the second surface 14 of the fiber structure 10. In other words, each second intersection 22 included in the second twill weave portion 32 is adjacent to another second intersection 22 different from the second intersection 22 in the first direction X.

[0045] The unit structure 30 is formed by alternating three types of first twill-forming portions 31a, 31b, and 31c and three types of second twill-forming portions 32a, 32b, and 32c in the second direction Y. The number of first yarns 11 contained in each of the first twill-forming portions 31a, 31b, and 31c is equal to the number of first yarns 11 contained in each of the second twill-forming portions 32a, 32b, and 32c. The number of second yarns 12 contained in each of the first twill-forming portions 31a, 31b, and 31c is equal to the number of second yarns 12 contained in each of the second twill-forming portions 32a, 32b, and 32c. In other words, the first twill-forming portions 31a, 31b, and 31c and the second twill-forming portions 32a, 32b, and 32c each contain the same number of first yarns 11 and second yarns 12. It is not necessary for the first yarns 11 and the second yarns 12 to be included in the same number in each of the first twill-forming portions 31a, 31b, 31c and in each of the second twill-forming portions 32a, 32b, 32c.

[0046] <Symmetry of the first and second surfaces of the fiber structure> Fig. 3 shows the fiber structure 10 in the range shown in Fig. 2 in a state where the fiber structure 10 is inverted while the second direction Y is fixed. In other words, the fiber structure 10 shown in Fig. 3 is the fiber structure 10 shown in Fig. 2 rotated around an axis extending in the second direction Y as the axis of rotation. In other words, Fig. 3 shows the second surface 14 of the portion of the fiber structure 10 where the first surface 13 is shown in Fig. 2. In Fig. 3, the portion shown by the two-dot chain line is the unit structure 30 shown by the two-dot chain line in Fig. 2, as viewed from the second surface 14.

[0047] The arrangement of the second intersection points 22 in the first direction X and the second direction Y in the portion shown by the dashed dotted line in Fig. 3 corresponds to the arrangement of the first intersection points 21 in the first direction X and the second direction Y on the first surface 13 of the unit feature 30. More specifically, the arrangement of the second intersection points 22 in the portion shown by the dashed dotted line in Fig. 3 is in line symmetry with the arrangement of the first intersection points 21 on the first surface 13 of the unit feature 30, with respect to the edge of the unit feature 30 in the second direction Y as the axis.

[0048] Furthermore, the arrangement of the first intersections 21 in the first direction X and the second direction Y in the portion indicated by the dashed-dotted line in FIG. 3 corresponds to the arrangement of the second intersections 22 in the first surface 13 of the unit feature 30 in the first direction X and the second direction Y. In other words, the arrangement of the first intersections 21 in the portion indicated by the dashed-dotted line in FIG. 3 matches the arrangement of the second intersections 22 in the first surface 13 of the unit feature 30 by inverting them in the second direction Y. The first surface 13 is formed by repeating the arrangement of the first intersections 21 and the second intersections 22 formed in the first surface 13 of the unit feature 30 in the first direction X and the second direction Y. The second surface 14 is formed by repeating the arrangement of the first intersections 21 and the second intersections 22 in the first direction X and the second direction Y, with the inversion of the arrangement in the second direction Y. Therefore, the second surface 14 matches the surface formed by inverting the first surface 13 in the second direction Y. In other words, in the fiber structure 10, the arrangement of the first intersections 21 and the second intersections 22 on the first surface 13 and the second surface 14 inverted in the first direction X and the second direction Y is consistent with each other.

[0049] <Method of manufacturing fiber reinforced composite materials> As shown in Fig. 6, the fiber-reinforced composite material 100 is produced by a pultrusion molding apparatus 90. More specifically, the pultrusion molding apparatus 90 produces the fiber-reinforced composite material 100 by pultrusion molding using the fiber structure 10 as a reinforcing substrate. Fig. 6 schematically shows the fiber structure 10, the pultrusion molding apparatus 90, and the fiber-reinforced composite material 100. The pultrusion molding apparatus 90 includes a supply section 91, an impregnation layer 92, a compression section 93, a heating mold 94, a pultrusion section 95, and a cutting section 96.

[0050] The supply unit 91 supplies the fiber structure 10 to the impregnation layer 92. The supply unit 91 feeds the fiber structure 10 in one direction. The fiber structure 10 fed from the supply unit 91 is a single layer. The supply unit 91 feeds the fiber structure 10 such that the one feeding direction of the fiber structure 10 coincides with the second direction Y. The fiber structure 10 is fed from the supply unit 91 by being pulled in the second direction Y by the drawing unit 95.

[0051] The impregnation layer 92 contains a liquid matrix resin 92a. The matrix resin 92a is a high-temperature molten resin. In the impregnation layer 92, the fiber structure 10 delivered from the supply unit 91 is impregnated with the matrix resin 92a. The fiber structure 10 passes through the impregnation layer 92 continuously in the second direction Y.

[0052] The matrix resin 92a is impregnated into each of the first yarns 11 and the second yarns 12, and the entire fiber structure 10 is also impregnated with the matrix resin 92a. In the fiber structure 10, the matrix resin 92a penetrates between adjacent first yarns 11 and between adjacent second yarns 12. In the fiber structure 10, the matrix resin 92a also penetrates between the first yarns 11 and the second yarns 12 at each of the first intersection 21 and the second intersection 22. The entire first surface 13 and the entire second surface 14 of the fiber structure 10 are each coated with the matrix resin 92a. As a result, the entire surface of the fiber structure 10 and gaps formed in the fiber structure 10 are filled with the matrix resin 92a.

[0053] The compressing unit 93 compresses the fiber structure 10 impregnated with the matrix resin 92a. By compressing the fiber structure 10 by the compressing unit 93, the entire fiber structure 10 is pressurized in the third direction Z, and the first yarns 11 and the second yarns 12 are pressurized in the third direction Z. By compressing the fiber structure 10 by the compressing unit 93, excess matrix resin 92a is removed from the fiber structure 10.

[0054] The fiber structure 10 impregnated with the matrix resin 92a, compressed by the compressing unit 93, is introduced into the heating mold 94. The heating mold 94 heats the fiber structure 10 impregnated with the matrix resin 92a. The heating mold 94 heats each of the matrix resin 92a and the fiber structure 10 together with a core or the like (not shown). The heating mold 94 thermally cures the matrix resin 92a to match the shape of the core or the like by the heating, thereby molding a fiber-reinforced composite material 100 using the fiber structure 10 as a reinforcing base material. The molding of the fiber-reinforced composite material 100 by the heating mold 94 is performed while the fiber-reinforced composite material 100 is moved in the second direction Y by the drawing unit 95.

[0055] The pulling unit 95 pulls the fiber reinforced composite material 100 heated in the heating mold 94 in the second direction Y, thereby pulling it out of the heating mold 94. The cutting unit 96 cuts the thermoset fiber reinforced composite material 100 of the matrix resin 92a to a desired length.

[0056] [Operation of this embodiment] The operation of this embodiment will be described. The unit structure 30 has a portion where two first intersections 21 are continuously aligned in the first direction X. This portion scrapes off the matrix resin 92a adhering to the inner surface of the heating mold 94 in the second direction Y during pultrusion molding. In other words, when the fiber structure 10 is pulled out of the heating mold 94, the unit structure 30 is pulled out together with the matrix resin 92a adhering to the inner surface of the heating mold 94. Because the unit structure 30 is a repeating unit of the fiber structure 10, there is a portion where two first intersections 21 are continuously aligned throughout the entire fiber structure 10 in the first direction X, and therefore, this scraping occurs throughout the entire first direction X. Furthermore, this scraping occurs on both the first surface 13 and the second surface 14 of the fiber structure 10.

[0057] [Effects of this embodiment] The effects of this embodiment will be described. (1) In the unit structure 30, the number of first intersections 21 in the first twill weave portion 31 is equal to the number of second intersections 22 in the second twill weave portion 32. In the fiber structure 10 having such a unit structure 30 as the smallest unit, the distribution of the first intersections 21 and second intersections 22 formed on the first surface 13 is also formed on the second surface 14. In other words, the fiber structure 10 has the distribution of the first intersections 21 and second intersections 22 on the first surface 13 also on the second surface 14.

[0058] Furthermore, the unit structure 30 can have a greater number of entanglements between the first yarns 11 and the second yarns 12 than when woven with, for example, a 2 / 2 twill, a 1 / 3 twill, or a 3 / 1 twill. Therefore, the fiber structure 10 has a similar distribution of the first intersections 21 and the second intersections 22 on the first side 13 and the second side 14, while having a greater number of entanglements in the unit structure 30 than when the fiber structure 10 has a twill weave portion formed solely by a 2 / 2 twill. In other words, when used as a reinforcing substrate for pultrusion, the fiber structure 10, even in a single layer, can suppress misalignment that occurs with pultrusion.

[0059] Furthermore, in the fiber structure 10, the first twill weave portion 31 has claws 23. Consider a situation in which the fiber structure 10 is pulled out of the heating mold 94 in the second direction Y. In this situation, the claws 23 can scrape off the matrix resin 92a adhering to the inner surface of the heating mold 94 over the entire unit structure 30 in the first direction X while pulling out the fiber structure 10. Furthermore, the fiber structure 10 can scrape off the matrix resin 92a from each of the first surface 13 and the second surface 14. This scraping can prevent the matrix resin 92a from adhering to the heating mold 94, thereby preventing the fiber-reinforced composite 100 from developing dents due to the adhesion of the matrix resin 92a. As described above, the fiber structure 10 can prevent misalignment and the fiber-reinforced composite 100 from developing dents during single-layer pultrusion molding.

[0060] (2) When two first intersections 21 are arranged side by side in the first direction X, the first yarn 11 included in the first intersection 21 is arranged side by side with two second yarns 12 in the third direction Z, and the two second yarns 12 are arranged side by side in the first direction X. In this case, the two second yarns 12 are slightly displaced toward each other in the first direction X by the first yarn 11 that crosses in the first direction X.

[0061] Next, consider a case where three second yarns 12 are lined up in the first direction X. Furthermore, consider a case where the central second yarn 12 of the three second yarns 12 is displaced to one side of the other second yarns 12 by a first yarn 11, and is displaced to the other side of the other second yarns 12 by a first yarn 11 different from the first yarn 11. In this case, the second yarn 12 extends in the second direction Y and meanders to both one side and the other side of the first direction X. The magnitude of the load caused by the meandering on the second yarn 12 increases as the wavelength of the meandering decreases. This is because, when the wavelength of the meandering is short, the angle at which the second yarn 12 bends when meandering increases.

[0062] In the textile structure 10, each of the plurality of first intersections 21 and each of the plurality of second intersections 22 is composed of four first yarns 11 and one second yarn 12. Therefore, the textile structure 10 can lengthen the wavelength of the meandering by increasing the interval at which the meandering occurs in the second direction Y. As a result, the textile structure 10 can reduce the meandering in the first direction X that occurs in the second yarns 12. As a result, the textile structure 10 can reduce the load acting on the second yarns 12.

[0063] (3) When the fiber-reinforced composite material 100 is manufactured by pultrusion molding using the fiber structure 10 as a reinforcing base material, the fiber-reinforced composite material 100 can be manufactured while suppressing misalignment in the fiber structure 10. Furthermore, even when a single-layer fiber structure 10 is used as a reinforcing base material, the above configuration can suppress adhesion of the matrix resin 92a to the inner surface of the heating mold 94 that molds the fiber structure 10 during pultrusion molding. In other words, by using the fiber structure 10 as a reinforcing base material, the fiber-reinforced composite material 100 can suppress the occurrence of dents.

[0064] [Example of change] The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other within the scope of technical compatibility.

[0065] The order in which the three types of first twill-forming portions 31a, 31b, 31c in the first twill weave portion 31 are arranged in the second direction Y is the first twill-forming portion 31a, the first twill-forming portion 31b, the first twill-forming portion 31c, but this is not limited to this. Also, the order in which the three types of second twill-forming portions 32a, 32b, 32c in the second twill weave portion 32 are arranged in the second direction Y is the second twill-forming portion 32a, the second twill-forming portion 32b, the second twill-forming portion 32c, but this is not limited to this.

[0066] In the unit structure 30, the first twill forming portions 31a, 31b, 31c and the second twill forming portions 32a, 32b, 32c do not have to be arranged alternately in the second direction Y. For example, any one of the three types of first twill forming portions 31a, 31b, 31c and any one of the first twill forming portions 31a, 31b, 31c that is different from that one of the first twill forming portions 31a, 31b, 31c may be adjacent to each other in the second direction Y.

[0067] In the unit structure 30, the first twill weave portion 31 and the second twill weave portion 32 may be aligned in the first direction X. For example, Fig. 7 shows a unit structure 30 in which the first twill weave portion 31 and the second twill weave portion 32 are aligned in the first direction X. That is, in the fiber structure 10 having the above configuration, the first twill weave portion 31 and the second twill weave portion 32 are aligned in the first direction X in the unit structure 30. In Fig. 7, the boundary lines between each of the three types of first twill-forming portions 31a and each of the three types of second twill-forming portions 32a are indicated by dashed dotted lines.

[0068] In this case, for example, in the unit structure 30, the gap at the location where the first twill weave portion 31 and the second twill weave portion 32 are interchanged can be made smaller than when the first twill weave portion 31 and the second twill weave portion 32 are aligned only in the second direction Y. The reason for this will be explained below with reference to Figs.

[0069] As shown in FIG. 2, a unit structure 30 in which a first twill weave portion 31 and a second twill weave portion 32 are aligned in the second direction Y is referred to as a unit structure 30α. On the other hand, as shown in FIG. 7, a unit structure 30 in which a first twill weave portion 31 and a second twill weave portion 32 are aligned in the first direction X is defined as a unit structure 30β.

[0070] Each of the unit structures 30α and 30β has a plurality of alternation points 40 where the first intersection points 21 and the second intersection points 22 are aligned in the second direction Y. In FIG. 2, one of the alternation points 40 in the unit structure 30α is indicated by a dashed line. Also, in FIG. 7, one of the alternation points 40 in the unit structure 30β is indicated by a dashed line. At the alternation points 40 in each of the unit structures 30α and 30β, the second yarn 12 bends from the second direction Y to the third direction Z and also bends from the third direction Z to the second direction Y. Therefore, a repulsive force is applied to each of the two adjacent first yarns 11 at the alternation point 40 in a direction separating them from each other. In FIG. 9, the direction in which the two first yarns 11 at the alternation point 40 are biased by the second yarn 12 is indicated by a double-headed arrow F.

[0071] This repulsive force creates a gap between the two first yarns 11. In the unit structure 30α, where the first twill weave portion 31 and the second twill weave portion 32 change places in the second direction Y, a region where the change point 40 exists throughout the first direction X is created. Furthermore, even when a plurality of unit structures 30α are connected in the first direction X, the change point 40 exists throughout the first direction X. Therefore, in the fiber structure 10 having the unit structure 30α, a very large gap is created between the two first yarns 11 at the change point 40. On the other hand, in the unit structure 30β, as shown in FIG. 7 , where the first twill weave portion 31 and the second twill weave portion 32 change places in the second direction Y, a region where the change point 40 exists throughout the first direction X is not created. Therefore, there are also regions where the first intersection portions 21 are aligned in the second direction Y and regions where the second intersection portions 22 are aligned in the second direction Y. Therefore, in the fiber structure 10 having the unit structure 30β, there are no very large gaps that occur in the fiber structure 10 having the unit structure 30α.

[0072] As a result, when a fiber-reinforced composite material 100 is manufactured by pultrusion molding using the fiber structure 10 as a reinforcing base material, it is possible to prevent the matrix resin 92a from accumulating in the gaps in the fiber structure 10. Furthermore, when pultrusion molding is performed using the fiber structure 10 as a reinforcing base material, it is possible to prevent misalignment in the manufactured fiber-reinforced composite material 100.

[0073] The number of first yarns 11 included in each of the first intersection portion 21 and the second intersection portion 22 does not have to be four. For example, as shown in Fig. 8 , the number of first yarns 11 included in each of the first intersection portion 21 and the second intersection portion 22 may be one.

[0074] The number of second yarns 12 included in each of the first intersection portion 21 and the second intersection portion 22 does not have to be 1. For example, the number of second yarns 12 included in each of the first intersection portion 21 and the second intersection portion 22 may be two or more. [Explanation of symbols]

[0075] 10...fiber structure, 11...plurality of first yarns, 12...plurality of second yarns, 13...first surface, 14...second surface, 21...first intersection, 22...second intersection, 30...unit structure, 31...first twill weave portion, 32...second twill weave portion, 92a...matrix resin as matrix material, 100...fiber reinforced composite, X...first direction, Y...second direction, Z...third direction.

Claims

1. a plurality of first threads extending in a first direction and arranged parallel to one another; a plurality of second yarns extending in a second direction perpendicular to the first direction and arranged parallel to one another; a first surface that is one surface in a third direction that is orthogonal to each of the first direction and the second direction; a second surface which is the other surface in the third direction; a plurality of first intersections where the first yarn and the second yarn are aligned in the third direction, the first yarn being located on the first surface, and the second yarn being located on the second surface; the first yarn and the second yarn are aligned in the third direction, and the first yarn is located on the second surface and the second yarn is located on the first surface; and a fiber structure that serves as a reinforcing substrate for a fiber-reinforced composite material, the fiber structure being formed by repeating a plurality of unit structures each consisting of a plurality of first intersection portions and a plurality of second intersection portions in the first direction and the second direction, The unit structure is a first twill portion forming a 2 / 1 twill weave having two of the first intersections and one of the second intersections along the first yarn; a second twill weave portion forming a 1 / 2 twill weave having one first intersection portion and two second intersection portions along the first yarn.

2. 2. The fiber structure according to claim 1, wherein each of the plurality of first intersections and each of the plurality of second intersections is composed of a plurality of the first yarns and one of the second yarns.

3. The fiber structure according to claim 1 , wherein in the unit structure, the first twill weave portion and the second twill weave portion are aligned in the first direction.

4. A fiber-reinforced composite material formed by impregnating a fiber structure with a matrix material, wherein the fiber structure is the fiber structure according to any one of claims 1 to 3.

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