Carbon fiber woven fabric

Abstract

To provide a high basis-weight carbon fiber woven fabric which has a small crimp and allows CFRP excellent in mechanical characteristics to be molded.SOLUTION: There is provided a carbon fiber woven fabric containing a carbon fiber in each of the warp and the weft, in which the woven fabric has a basis weight of 300 g / m2 or more and 800 g / m2 or less, and an arctan (td / 50) of 1.0° or more and 3.3° or less, where t (mm) is a thickness of the woven fabric and d (yarns / 25 mm) is a weaving density.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a carbon fiber fabric that exhibits excellent properties when used in fiber composite materials. More specifically, the present invention relates to a carbon fiber fabric that suppresses a decrease in mechanical properties conventionally observed in carbon fiber fabrics with a large fabric weight per unit area by controlling the crimp angle of the woven yarns formed by the interlacing of warp yarns and weft yarns.

Background Art

[0002] Carbon fiber reinforced plastic (CFRP) composed of carbon fibers and a matrix resin is widely used in various industrial applications because of its light weight and excellent mechanical properties. As a reinforcing base material used for CFRP, a carbon fiber fabric woven by a shuttle loom or a rapier loom and having woven yarns made of carbon fibers is often used as a reinforcing base material for CFRP.

[0003] CFRP is suitably used as an aircraft member, a pressure vessel member, an automobile member, a sports member, and a repair and reinforcement material in the civil engineering and construction fields by taking advantage of its excellent performance. However, current CFRP has a problem that its cost is higher than that of conventional metal materials, and cost reduction of CFRP is an issue. As a measure for cost reduction, it is effective to maximize the high-performance characteristics of carbon fibers and reduce the amount of carbon fibers used. Further, when laminating a plurality of reinforcing base materials such as prepregs and carbon fiber fabrics, it is also effective to increase the amount of carbon fibers contained in each layer and shorten the base material preparation and molding time.

[0004] As a normal reinforcing fabric for this reinforcing base material, a fabric is made using reinforcing fiber yarns in which reinforcing fibers are converged into a substantially circular cross-section. Therefore, in the woven state, the cross-section of the reinforcing fiber yarn at the intersection where the warp yarns and weft yarns intersect is elliptical, and the woven yarns are greatly crimped. In particular, in a reinforcing fabric using thick reinforcing fiber yarns, this tendency becomes more pronounced because the thick weft yarns and warp yarns intersect. When such a reinforcing fabric with greatly crimped reinforcing fiber yarns is used as an FRP material, the stress acting on the FRP material concentrates at the intersections where the woven yarns are crimped and becomes a starting point for fracture. Therefore, the high mechanical properties characteristic of the reinforcing fibers cannot be fully exhibited.

[0005] As a measure to reduce the crimp of the woven yarns, there is a twill weave structure with fewer intersection points between the woven yarns. By adopting this structure, the crimp of the woven yarns can be reduced, and the expression of high mechanical properties becomes possible. However, due to fewer intersections, the restraint of the woven yarns becomes weak. In the case of a molding method such as hand lay-up molding where the matrix resin is impregnated while squeezing with a roller or the like, or in the case of a molding method such as RTM (Resin Transfer Molding) where the matrix resin is impregnated under high pressure, the shape of the fabric collapses and the reinforcing fibers tend to meander, and there is a problem that the high mechanical properties characteristic of the reinforcing fibers cannot be fully exhibited. Also, there is a problem that warping may occur in the CFRP due to the curing shrinkage of the resin after molding, and it cannot be adopted for members that require precision.

[0006] In response to such problems, Patent Document 1 discloses a reinforcing fiber fabric woven from thin and wide flat carbon fibers. This fabric is a reinforcing fiber fabric using flat reinforcing fibers with a yarn width / thickness ratio of 20 or more as at least one of the warp yarns and weft yarns, and a flat yarn fabric with small crimp of the woven yarns is disclosed.

[0007] Patent Document 2 discloses a reinforcing fiber fabric in which, in addition to the yarn width / yarn thickness ratio, the weave density, strand fineness, and fabric thickness are specified. However, the fabric areal density is 300 g / m 2The following fabrics are targeted, and in the areas with high fabric areal density, the above-mentioned problems have not been solved.

[0008] Patent Document 3 discloses a reinforcing fiber fabric with a crimp angle of less than 1 degree. However, similar to Patent Document 2, in the areas with high fabric areal density, the above-mentioned problems have not been solved.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0010] In the reinforcing fiber fabric described in Patent Document 1, when the fabric areal density is large and the crimp angle is small, the number of intersections of the warp and weft yarns is small, so the warp and weft yarns are easy to move, and the reinforcing fibers are easy to meander during molding. As a result, there is a problem that the high mechanical properties characteristic of the reinforcing fibers are not fully exhibited.

[0011] Patent Documents 2 and 3 have problems with reinforcing fiber fabrics having a high fabric areal density.

[0012] An object of the present invention is to provide a carbon fiber fabric substrate that can fully exhibit the high mechanical properties of carbon fibers and has excellent moldability even with a high fabric areal density.

Means for Solving the Problems

[0013] In order to solve the above problems, the present inventor has found a carbon fiber fabric having the following characteristics and has completed the present invention. That is, the present invention has the following configuration. [1] A carbon fiber fabric containing carbon fibers in each of the warp and weft yarns, with a fabric weight of 300 g / m 2 or more and 800 g / m 2 or less, and when the fabric thickness is t [mm] and the weave density is d [threads / 25 mm], arctan(td / 50) is 1.0° or more and 3.3° or less. [2] The carbon fiber fabric according to [1], wherein the fineness of the carbon fiber is 1,000 g / m (1,000 tex) or more and 4,000 g / m (4,000 tex) or less. [3] The carbon fiber fabric according to [1] or [2], wherein the sizing adhesion rate of the carbon fiber is 0.5 mass% or more and 10 mass% or less. [4] The carbon fiber fabric according to any one of [1] to [3], wherein the shear rigidity value is 0.40 N / ° or more and 10 N / ° or less. [5] The carbon fiber fabric according to any one of [1] to [4], wherein the stiffness and softness in the warp direction and / or the weft direction is 170 mm or more and 400 mm or less. [6] The carbon fiber fabric according to any one of [1] to [5], wherein the opening ratio is 0% or more and 10% or less. [7] The carbon fiber fabric according to any one of [1] to [6], wherein the tensile strength of the carbon fiber is 3,000 MPa or more and 7,000 MPa or less, and the tensile elastic modulus is 200 GPa or more and 600 GPa or less. [8] The carbon fiber fabric according to any one of [1] to [7], wherein the warp and / or weft yarns contain heat-sealing fibers, and the carbon fibers are blocked by the heat-sealing fibers.

Advantages of the Invention

[0014] According to the carbon fiber fabric of the present invention, excellent mechanical properties of the carbon fiber can be exhibited even at a high fabric weight of 300 g / m 2 or more. Thereby, particularly in applications where the amount of carbon fiber used is large, it is possible to reduce the amount of carbon fiber used, shorten the production time and molding time of the carbon fiber fabric, and reduce the cost of CFRP.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

DETAILED DESCRIPTION OF THE INVENTION

[0016] The carbon fiber fabric of the present invention is a carbon fiber fabric containing carbon fibers in each of the warp yarn and the weft yarn as weaving yarns, and the fabric areal density is 300 g / m 2 or more and 800 g / m 2 or less, and when the fabric thickness is t [mm] and the weaving density is d [threads / 25 mm], it is a carbon fiber fabric in which arctan(td / 50) is 1.0° or more and 3.3° or less.

[0017] Hereinafter, the configuration of the carbon fiber fabric of the present invention will be described in detail.

[0018] In the cross-section of the fabric of the present invention, the line connecting the intersections of the two perpendicular lines passing through the centers of two adjacent warp yarns or weft yarns and the center line of one weft yarn or warp yarn intersecting with the warp yarn or weft yarn, and the angle θ between the line parallel to the arrangement direction of the warp yarn or weft yarn is 1.0° or more and 3.3° or less. As will be described later, when the fabric thickness is t [mm] and the weaving density is d [threads / 25 mm], the crimp angle θ is obtained by arctan(td / 50).

[0019] The crimp angle θ in the above fabric will be described in more detail with reference to the drawings. FIG. 1 is a partial plan view of a carbon fiber fabric 3 made of a fabric using carbon fiber yarns (warp yarn 1, weft yarn 2) as weaving yarns, and FIG. 2 is a cross-sectional view of the carbon fiber fabric 3 taken along the line A-A in FIG. 1.

[0020] In FIG. 2, two adjacent warp threads 1a are arranged at a weaving density d [threads / 25 mm]. The angle θ formed between a straight line 6 connecting intersections 5a and 5b between perpendicular lines 4a and 4b passing through the centers of the warp threads 1a and the center line 2c of one weft thread 2a intersecting the warp threads 1a, and a straight line 7 parallel to the arrangement direction of the warp threads 1a, is the crimp angle θ as defined in the present invention.

[0021] In FIG. 2, although the crimp angle parallel to the warp thread arrangement direction is shown, the crimp angle θ with respect to the weft thread arrangement direction can also be defined in the same manner for the B-B cross section in FIG. 1. Therefore, in the embodiment shown in FIG. 2, assuming the center-to-center distance 8 between the two warp threads 1a is 25 / d [mm] and the thickness 10 of the fabric is t [mm], the above crimp angle θ is obtained by the following formula. θ = arctan(td / 50) [°].

[0022] The thickness t of the fabric is measured in accordance with JIS R 7602:2008. That is, it is the thickness when a load of 50 kPa is applied for 20 seconds using a dial gauge. The weaving density d is measured in accordance with JIS R 7602:2008, that is, the number of warp threads arranged per 25 mm.

[0023] In the carbon fiber fabric of the present invention, when the fabric areal density is 300 g / m 2 or more and 800 g / m 2 or less, the above crimp angle θ is 1.0° or more and 3.3° or less. When the fabric areal density is 300 g / m 2 or more and the crimp angle θ is less than 1.0°, since the weaving density is small, the reinforcing fibers tend to meander during molding, and the high mechanical properties characteristic of the reinforcing fibers are not fully exhibited. When the crimp angle θ exceeds 3.3°, when stress acts in the warp thread direction after CFRP formation, the stress concentration at the intersection increases, and the high mechanical properties characteristic of the reinforcing fibers are not fully exhibited. When the fabric areal density is 800 g / m 2When it exceeds this value, it becomes difficult for the resin to impregnate into the carbon fiber bundles during CFRP formation, and unimpregnated portions may remain in the reinforcing fibers, or the reinforcing fibers may meander or be damaged, such as by strongly squeezing the reinforcing fibers to impregnate them, resulting in a decrease in the excellent mechanical properties of the reinforcing fibers. When the fabric basis weight is less than 300 g / m 2 If it is less than this value, when a large amount of reinforcing fibers is required, it is necessary to laminate multiple layers of the fabric, and there is a concern about an increase in cost due to an increase in working time. In addition, voids or foreign substances may remain between the layers, which may reduce the mechanical properties. The fabric basis weight is preferably 350 g / m 2 or more and 700 g / m 2 or less, more preferably 380 g / m 2 or more and 600 g / m 2 or less. The crimp angle θ is preferably 1.0° or more and 2.5° or less, more preferably 1.0° or more and 2.0° or less. When the crimp angles θ of the warp and weft yarns are different, it is preferable that both the crimp angle θ of the warp yarn and the crimp angle θ of the weft yarn are within the above range. However, when CFRP is formed, if high mechanical properties are not required for either the warp or weft direction, the crimp angle θ of the woven yarn in that direction does not necessarily have to be within the above range.

[0024] Also, it is preferable to use the same type of carbon fiber for the warp and weft yarns. When the carbon fibers of the warp and weft yarns are different, the mechanical properties in the warp and weft directions may be different when CFRP is formed, and the handling may be limited. However, depending on the use of CFRP, it may be preferable to use different carbon fibers for the warp and weft yarns. In that case as well, in each direction of the warp and weft yarns, it is preferable that arctan(td / 50) is 1.0° or more and 3.3° or less.

[0025] In the present invention, the fineness of the carbon fiber is preferably 1.000 g / m (1,000 tex) or more and 4.000 g / m (4,000 tex) or less. If it is less than 1.000 g / m (1,000 tex), it is necessary to increase the weaving density to increase the fabric areal density, the crimp angle θ becomes large, and the mechanical properties may deteriorate. If it exceeds 4.000 g / m (4,000 tex), it becomes a soft fabric with a small weaving density, and the reinforcing fibers are likely to meander during molding, and the high mechanical properties characteristic of the reinforcing fibers may not be fully exhibited. More preferably, it is 1.500 g / m (1,500 tex) or more and 2.000 g / m (2,000 tex) or less, and even more preferably, it is 1.600 g / m (1,600 tex) or more and 1.800 g / m (1,800 tex) or less.

[0026] The aperture ratio of the carbon fiber fabric of the present invention is preferably 0% or more and 10% or less. The closer the aperture ratio is to 0%, the more uniformly the warp and weft yarns are arranged, so that the carbon fibers are less likely to meander during molding. However, on the other hand, when impregnating with the matrix resin, the air bubbles in the carbon fibers and the resin applied in excess tend to be less likely to be discharged. Therefore, the aperture ratio is more preferably 0.1% or more. If it exceeds 10%, the carbon fibers are likely to move, and the meandering of the carbon fibers may easily occur during molding. Regarding the range of the aperture ratio, more preferably, it is 0.1% or more and 4% or less, and even more preferably, it is 0.1% or more and 1% or less.

[0027] Here, the aperture ratio of the carbon fiber fabric is the area S on the fabric 1 When a region is set, the area S 1 The area of the voids formed in the warp and weft yarns within is S 2 When used, it refers to the value defined by the following formula. Aperture ratio [%] = S 2 / S 1 × 100.

[0028] For measuring the opening ratio, the entire width of the fabric may be captured as an image using a scanner, and the opening ratio may be derived using image processing software. When the fabric width is wide, a plurality of rectangles with at least one side of 20 cm or more may be evenly sampled in the width direction, the opening ratio for each image may be calculated, and the average value may be used as the opening ratio of the carbon fiber fabric.

[0029] As the carbon fiber used for the warp and weft, for example, polyacrylonitrile (PAN-based), pitch-based, cellulose-based, carbon fibers grown by vapor phase growth using hydrocarbons, graphite fibers, etc. can be used, and two or more of these may be used in combination. Preferably, PAN-based carbon fibers with excellent balance of mechanical properties and price are good. Also, the carbon fiber preferably has a tensile strength of 3,000 MPa or more and 7,000 MPa or less, and a tensile elastic modulus of 200 GPa or more and 600 GPa or less. More preferably, the tensile strength is 4,000 MPa or more and 6,000 MPa or less, and the tensile elastic modulus is 210 GPa or more and 260 GPa. Even more preferably, the tensile strength is 4,500 MPa or more and 6,000 MPa or less, and the tensile elastic modulus is 220 GPa or more and 250 GPa or more. Depending on the mechanical properties required when made into CFRP, it is also possible to use carbon fibers with a tensile strength exceeding 7,000 MPa or a tensile elastic modulus exceeding 600 GPa, but the cost of the carbon fiber increases. Also, when using carbon fibers with a tensile strength of less than 3,000 MPa or a tensile elastic modulus of less than 200 GPa, the mechanical properties when made into CFRP may be insufficient, so the above range of mechanical properties is preferable.

[0030] Also, it is preferable that the carbon fiber is flat. Also, it is preferable that there is substantially no twist and each fiber is parallel. Here, "substantially no twist" means a state where there is no twist of 1 turn or more per 1 m of yarn length. That is, it refers to a practically untwisted state, and it is preferable that there is substantially no twist in the state of the fabric. As a method of making such a fabric, there is a method of unwinding a bobbin of untwisted flat carbon fiber laterally and supplying the warp and weft so that no unwinding twist is added to make a fabric.

[0031] Furthermore, the sizing adhesion rate of the carbon fiber is preferably 0.5% by mass or more and 10% by mass or less. If it is less than 0.5% by mass, the convergence property of the carbon fiber is low, and the reinforcing fiber is likely to meander during molding, and the high mechanical properties characteristic of the reinforcing fiber may not be fully exhibited. If it exceeds 10% by mass, the convergence property of the carbon fiber is strong, and the formability of the fabric and the impregnation property of the matrix resin into the carbon fiber may deteriorate. Preferably, it is 0.6% by mass or more and 3.0% by mass or less, and more preferably 0.8% by mass or more and 1.6% by mass or less. By using carbon fiber with the sizing adhesion rate within the above range, it is possible to obtain a CFRP that exhibits higher mechanical properties, which is preferable.

[0032] The value of the shear rigidity of the carbon fiber fabric of the present invention is preferably 0.40 N / ° or more and 10 N / ° or less. If it is less than 0.40 N / °, the shape of the fabric may easily collapse during shaping or molding. If it exceeds 10 N / °, the fabric is too hard and the formability may deteriorate. More preferably, it is 0.45 N / ° or more and 5.0 N / ° or less, and even more preferably 0.50 N / ° or more and 1.0 N / ° or less.

[0033] The shear rigidity of the carbon fiber fabric is measured by the picture frame method using the two-side gripping method, which is a method for evaluating the shear deformation performance. Hereinafter, this method will be described with reference to the drawings. Fig. 3 shows a schematic diagram of the picture frame method using the two-side gripping method. The upper and lower parts of the picture frame jig are attached to a universal material testing machine (omitted in Fig. 3) so that the four corners surrounded by 11a, 11b, 11c, and 11d of the picture frame jig 11 are 90 degrees. Here, 11a and 11b have a structure with gripping parts that can grip the test piece. The picture frame jig and the carbon fiber fabric from which the test piece to be described later is cut out are left standing at 25 °C for 1 hour before the start of the test. After standing, five test pieces 13 with a long side of 220 mm and a short side of 150 mm are cut out from the carbon fiber fabric. The short side of the cut-out test piece 13 is fixed to the gripping part of 11a. At this time, the distance between 11a and 11b is 200 mm. Also, the other end of the short side of the test piece 13 is attached to the clamping part of 11b so that the long side of the test piece 13 is parallel to 11c and 11d. After attaching the test piece 13 as described above, after confirming that the measurement angle 12 is 90 °, the picture frame jig 11 is pulled in the vertical direction at a speed of 50 mm / min, and the tensile force F [N] and the measurement angle 12 at that time are measured (the measurement angle 12 is denoted as α). Then, the shear angle β [°] calculated from the following formula and ΔF / Δβ when β [°] is between 0.1 and 1.0 are calculated as the shear rigidity, and the average of the five is taken as the shear rigidity of the carbon fiber fabric. β [°]=90 - α.

[0034] At this time, when the carbon fiber types and configurations are different in the warp direction and the weft direction, two types of test pieces are prepared: one with the long side of the test piece in the warp direction and the short side in the weft direction, and the other with the long side of the test piece in the weft direction and the short side in the warp direction, and the test is carried out in the same manner. In this case, it is preferable that the shear rigidity is within the above range in both directions.

[0035] The carbon fiber fabric of the present invention preferably has a stiffness-flexibility in the warp direction and / or the weft direction of 170 mm or more and 400 mm or less. If it is less than 170 mm in both directions, the fabric is too soft and may easily collapse during shaping. If it exceeds 400 mm in both directions, the fabric becomes too hard and the formability may deteriorate. Preferably, it is 180 mm or more and 250 mm or less, more preferably 185 mm or more and 210 mm or less.

[0036] Here, the method for measuring the stiffness-flexibility of the carbon fiber fabric will be described with reference to FIG. 4. From the carbon fiber fabric, five rectangular test pieces 16 with a long side of 300 mm and a short side of 50 mm are cut out, distinguishing between the front and back. The test pieces 16, the horizontal table 14 described below, and the pressing jig are left standing in a situation of room temperature 25°C for 1 hour. Here, the test piece 16 is laid flat on a horizontal table. Next, the test piece 16 is placed on the horizontal table 14 as shown in FIG. 4. The length of the long side of the horizontal plane 15 of the horizontal table 14 is 300 mm. Then, one end 18 of the short side of the test piece is aligned with the boundary line between the inclined plane 19 and the horizontal plane 15, and a metal pressing jig (omitted in FIG. 4) with a width of 75 mm and a length of 300 mm is placed thereon. Then, the pressing jig is horizontally moved toward the inclined plane 19 at a speed of about 3 mm / second, and the movement is stopped at the position where the inclined plane 19 and one end 18 of the short side of the test piece come into contact. The amount of movement of the position of one end 17 of the short side of the test piece at this time is read in 1 mm units and taken as the movement amount 20 of the test piece. This is measured 10 times for each of the 5 test pieces, turning the front and back over 2 times each, and the average of the obtained values is taken as the stiffness-flexibility of the carbon fiber fabric. At this time, when the carbon fiber types and configurations are different in the warp direction and the weft direction, two types of test pieces are prepared, one with the long side of the test piece in the warp direction and the short side in the weft direction, and the other with the long side of the test piece in the weft direction and the short side in the warp direction, and the test is carried out in the same manner.

[0037] The carbon fiber fabric of the present invention preferably has a form in which heat-sealing fibers are included in the warp yarns and / or weft yarns, and the carbon fibers are blocked by the heat-sealing fibers. The fact that the carbon fibers are blocked by the heat-sealing fibers means a state in which the heat-sealing fibers are heated and welded to the carbon fibers to fix the carbon fibers to each other. Examples of the heat-sealing fibers include, but are not limited to, thermoplastic fibers such as polyamide (nylon) fibers, polyethylene fibers, and polyurethane fibers. If the heat-sealing fibers are folded in the carbon fiber yarn, the adhesive force with the entangled carbon fibers will be weakened. However, in the case of a carbon fiber fabric using flat carbon fibers, since the carbon fibers are not easily folded, the adhesive force of the heat-sealing fibers is easily exerted.

[0038] Due to the high specific strength and specific modulus of elasticity derived from carbon fibers, the carbon fiber fabric of the present invention can be suitably used in various fields such as aircraft members, pressure vessel members, automobile members, sports members, and repair and reinforcement materials in the civil engineering and construction fields by various molding methods such as RTM (Resin Transfer Molding), RFI (Resin Film Infusion), RIM (Resin Injection Molding), vacuum-assisted RTM, press molding, and hand lay-up molding. Among them, for a process such as hand lay-up molding in which a resin (for example, an epoxy resin, an unsaturated polyester resin, a vinyl ester resin, a urethane resin, an acrylic resin, etc.) that becomes a matrix resin of CFRP is applied to a carbon fiber fabric and the fabric is impregnated with the resin while squeezing the fabric with a roller or the like, or a molding method such as RTM molding in which a matrix resin is impregnated into a base material at high pressure, by using the carbon fiber fabric of the present invention, it is possible to expect the excellent mechanical properties of the carbon fibers to be exhibited. Further, the lamination structure at the time of forming CFRP is not particularly limited, and it may be used in a single layer, or may be laminated in multiple layers in combination with other reinforcing base materials.

Examples

[0039] Hereinafter, the present invention will be described in more detail with reference to examples.

[0040] (1) Materials used for the carbon fiber fabric [Carbon fiber] · "Torayca (registered trademark)" T700SC-24000-50C (manufactured by Toray Industries, Inc., tensile strength; 4,900 MPa, tensile modulus of elasticity; 230 GPa, sizing adhesion rate; 1.0 mass%, fineness; 1.650 g / m (1,650 tex), density; 1.80 g / cm 3 ) · "Torayca (registered trademark)" T700SC-12000-50C (manufactured by Toray Industries, Inc., tensile strength; 4,900 MPa, tensile modulus of elasticity; 230 GPa, sizing adhesion rate; 1.0 mass%, fineness; 0.800 g / m (800 tex), density; 1.80 g / cm 3 ) · "Torayca (registered trademark)" T700SC-12000-60E (manufactured by Toray Industries, Inc., tensile strength; 4,900 MPa, tensile modulus of elasticity; 230 GPa, sizing adhesion rate; 0.3 mass%, fineness; 0.800 g / m (800 tex), density; 1.80 g / cm 3 )

[0041] [Heat-sealing fiber] · "Elder (registered trademark)" (manufactured by Toray Industries, Inc., low melting point nylon thread, fineness; 54.8 decitex, melting point; 110 °C).

[0042] (2) Fabric property evaluation For the carbon fiber fabric to be evaluated, the shear rigidity and the stiffness-softness were measured by the above evaluation method.

[0043] (3) CFRP evaluation The carbon fiber fabric to be evaluated was cut out into 30 cm × 30 cm, and epoxy resin (AUR80 manufactured by Toray Building Materials Co., Ltd.) was applied as a matrix resin. After impregnating the resin while squeezing with a roller, it was left at room temperature for 1 week to obtain a CFRP cured plate. Using the obtained cured plate, a tensile test corresponding to JIS A 1191:2021 was carried out, and the tensile strength and the tensile modulus of elasticity were measured.

[0044] [Example 1] The "Toreca (registered trademark)" T700SC-24000-50C aligned parallel to the 1 direction was used as the warp yarn, and the "Toreca (registered trademark)" T700SC-24000-50C and the "Elder (registered trademark)" were inserted in the perpendicular direction to weave a carbon fiber fabric with a plain weave structure having a weave density d of 3.17 threads / 25 mm. Next, the fabric was heated so that the surface temperature of the fabric became 130°C to melt the heat-sealing fiber, and a carbon fiber fabric in which the warp yarn and the weft yarn were sealed was obtained. The fabric areal density was 418 g / m 2 The fabric thickness t measured according to JIS R 7602:2008 was 0.46 mm, the aperture ratio was 0.5%, and the crimp angle θ obtained by arctan(td / 50) was 1.7°.

[0045] For the obtained fabric, when measured according to the above (2) fabric property evaluation and (3) CFRP evaluation, the shear rigidity values were 0.58 N / ° in the warp direction and 0.60 N / ° in the weft direction, the stiffness-flexibility was 167 mm in the warp direction and 192 mm in the weft direction, the tensile strength was 4,724 MPa, and the tensile elastic modulus was 246 GPa.

[0046] [Comparative Example 1] A carbon fiber fabric was obtained in the same manner as in Example 1 except that the "Toreca (registered trademark)" T700SC-12000-50C was used for the warp yarn and the "Toreca (registered trademark)" T700SC-12000-50C and the "Elder (registered trademark)" were used for the weft yarn so that the weave density d became 6.57 threads / 25 mm. The fabric areal density was 427 g / m 2 The fabric thickness t measured according to JIS R 7602:2008 was 0.54 mm, the aperture ratio was 1.7%, and the crimp angle θ obtained by arctan(td / 50) was 4.1°.

[0047] When the obtained fabric was measured according to the above (2) fabric property evaluation and (3) CFRP evaluation, the shear rigidity value was 0.36 N / ° in the warp direction and 0.34 N / ° in the weft direction, and the stiffness flexibility was 169 mm in the warp direction and 167 mm in the weft direction. Compared with Example 1, it was a soft fabric in which the reinforcing fibers were likely to meander. Also, the tensile strength was 4,073 MPa, the tensile elastic modulus was 220 GPa, and due to the large crimp angle θ, the tensile strength and the tensile elastic modulus decreased.

[0048] [Comparative Example 2] "Trekka (registered trademark)" T700SC-12000-60E was used for the warp and weft yarns, and weaving was performed so that the weaving density d was 6.27 yarns / 25 mm. A carbon fiber fabric was obtained in the same manner as in Example 1 except that the warp and weft yarns were not fixed. The fabric areal density was 403 g / m 2 The fabric thickness t measured based on JIS R 7602:2008 was 0.47 mm, the opening ratio was 4.2%, and the crimp angle θ obtained by arctan(td / 50) was 3.4°.

[0049] When the obtained fabric was measured according to the above (2) fabric property evaluation, the shear rigidity value was 0.11 N / °, and the stiffness flexibility was 128 mm. Compared with Example 1 and Comparative Example 1, the fabric was very soft and the meandering of the reinforcing fibers was likely to occur. Although an attempt was made to perform molding for CFRP evaluation, a large meandering of the reinforcing fibers occurred, making it impossible to carry out.

[0050] The results of the above Examples and Comparative Examples are summarized in Table 1. The carbon fiber fabric of the present invention is not limited to the above-described examples and can be used in a wide range of applications.

[0051]

Table 1

Industrial Applicability

[0052] According to the carbon fiber fabric of the present invention, 300 g / m 2 or more and 800 g / m 2While having the following high fabric areal density, due to the low crimp angle, excellent mechanical properties are exhibited, and CFRP can be molded in which carbon fibers are less likely to meander in the resin impregnation process. For the reasons described above, the carbon fiber fabric of the present invention is suitably used in a wide range of fields such as aircraft members, pressure vessel members, automobile members, sports members, and repair and reinforcement materials in the civil engineering and construction fields.

Explanation of symbols

[0053] 1, 1a warp yarns 2, 2a weft yarns 2c center line of the weft yarn 3 carbon fiber fabric 4a, 4b perpendicular lines passing through the centers of the warp yarns 5a, 5b intersection points of the perpendicular lines passing through the centers of the warp yarns and the center line of the weft yarn 6 straight line connecting between 5a and 5b 7 straight line parallel to the arrangement direction of the warp yarns θ crimp angle 8 center - to - center distance between two warp yarns 1a (equal to 25 / d) 9 t / 2 (half of the fabric thickness t) 10 fabric thickness t 11 picture frame jig 11a, 11b, 11c, 11d components of the picture frame jig 12 measurement angle 13 test piece 14 horizontal table 15 horizontal plane 16 test piece 17, 18 one end of the short side of the test piece 19 inclined plane 20 movement amount of the test piece

Claims

1. A carbon fiber woven fabric containing carbon fibers in both the warp and weft yarns, and having a fabric weight of 300 g / m ２ 800g / m or more ２ and wherein, when the woven fabric thickness is t [mm] and the weaving density is d [threads / 25 mm], the arctan (td / 50) is 1.0° or more and 3.3° or less.

2. 2. The carbon fiber fabric according to claim 1, wherein the carbon fibers have a fineness of 1.000 g / m (1,000 tex) or more and 4.000 g / m (4,000 tex) or less.

3. The carbon fiber fabric according to claim 1 or 2, wherein a sizing adhesion rate of the carbon fibers is 0.5% by mass or more and 10% by mass or less.

4. 3. The carbon fiber fabric according to claim 1, wherein the shear stiffness is 0.40 N / ° or more and 10 N / ° or less.

5. 3. The carbon fiber fabric according to claim 1, wherein the bending resistance in the warp direction and / or the weft direction is 170 mm or more and 400 mm or less.

6. 3. The carbon fiber fabric according to claim 1, wherein the opening ratio is from 0% to 10%.

7. 3. The carbon fiber fabric according to claim 1, wherein the carbon fibers have a tensile strength of 3,000 MPa or more and 7,000 MPa or less and a tensile modulus of elasticity of 200 GPa or more and 600 GPa or less.

8. 3. The carbon fiber woven fabric according to claim 1, wherein the warp and / or weft yarns contain heat-sealable fibers, and the carbon fibers are filled with the heat-sealable fibers.

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