Fiber reinforced plastic

Abstract

The present invention aims to provide a fiber-reinforced plastic having a protrusion portion, which is lightweight and excellent in mechanical properties and appearance quality, and which is formed in a shape having a plate-shaped portion and at least one protrusion portion protruding from at least one side surface of the plate-shaped portion, the plate-shaped portion having at least one layer (unidirectional layer) in which a plurality of reinforcing fibers are aligned in one direction in a matrix resin, in the fiber-reinforced plastic, the aforementioned protrusion portion extends in at least two different directions, and at least two of the directions in which the aforementioned protrusion portion extends are neither parallel nor perpendicular to each other, and all of the directions in which the aforementioned protrusion portion extends are neither parallel nor perpendicular to the fiber orientation direction in any of the unidirectional layers in the aforementioned plate-shaped portion, respectively.

Description

Technical Field

[0001] The present invention relates to fiber-reinforced plastics having a plate-like portion and a protrusion extending from at least one side of the plate-like portion, and to fiber-reinforced plastics having the aforementioned plate-like portion and protrusions formed from a plurality of reinforcing fibers and a matrix resin. Background Technology

[0002] Fiber-reinforced plastics, formed from reinforcing fibers and matrix resins, are attracting attention due to their high specific strength, specific elastic modulus, excellent mechanical properties, and high functional characteristics such as weather resistance and chemical resistance. They are expected to be effectively utilized in a wide range of fields, including industry, sports, medicine, and information and communication.

[0003] Furthermore, in order to improve the mechanical properties of fiber-reinforced plastics and promote thinner walls and lighter weight while maintaining these properties, efforts have been made to refine the cross-sectional shape of the molded parts, resulting in the design of fiber-reinforced plastics with varying wall thicknesses and rib shapes. In particular, rib shapes are effective in preventing warping of wide planar portions of the molded parts, but because the shape becomes more complex, there are challenges in terms of moldability and mass production.

[0004] Methods for manufacturing fiber-reinforced plastics with high functional properties include autoclave molding and pressure molding. In autoclave molding, a semi-cured material, called a prepreg, obtained by impregnating a thermosetting resin (as the matrix resin) into a continuous sheet or fabric of reinforcing fibers, is layered. The matrix resin is then cured by heating and pressurizing in a high-temperature autoclave (autoclave) to form the fiber-reinforced plastic. In pressure molding, the aforementioned prepregs are layered, the resulting material is placed into a mold, and heated and pressurized using a press to cure the thermosetting resin matrix resin; alternatively, a prepreg impregnated with a thermoplastic resin as the matrix resin is softened or melted, molded, and then cooled and demolded to form the final product. Especially in pressure molding using thermosetting resins, prepregs made by using fast-curing thermosetting resins as the matrix resin and impregnating them with reinforcing fibers can produce molded products in a short time. Therefore, as a high-productivity molding method, it has attracted attention in recent years.

[0005] In the molding method using the prepreg preform described above, when producing molded articles with complex shapes such as varying wall thickness or ribbed shapes, the following method is possible: subdivide the desired fiber-reinforced plastic cross-section into plate-shaped parts, rib-shaped parts, etc., mold each part separately, and then join them using adhesives or thermal fusion bonding. However, since the bonding process is time-consuming and costly, and the strength and rigidity of the joint are lower than other parts, failure will occur at the joint first, making it difficult to fully utilize the excellent mechanical properties and durability of the fiber-reinforced plastic.

[0006] On the other hand, there is a method that involves shaping the preform on a mold before molding, followed by molding. While this method solves the problem of damage caused by the joint, the shaping process is time-consuming, thus raising concerns about production efficiency and cost.

[0007] Furthermore, in fiber-reinforced plastics using short reinforcing fibers with lengths of a few millimeters to tens of millimeters, protrusions are more easily formed. For example, if the matrix resin is a thermosetting resin, compression molding using SMC (Sheet Molding Compound) or BMC (Bulk Molding Compound) can be used; if it is a thermoplastic resin, injection molding can be used. However, SMC and BMC have the following problems: uneven distribution and orientation of reinforcing fibers inevitably occur during their manufacturing process, resulting in a decrease in the mechanical properties of the molded product or a larger deviation in its property values. In addition, in injection molding, the amount of reinforcing fibers is small, and molding cannot be achieved without using short reinforcing fibers, thus significantly reducing the mechanical properties of the molded product. Therefore, as described above, it is difficult to manufacture fiber-reinforced plastics with protrusions suitable for components requiring particularly high mechanical properties and durability.

[0008] Attempts to improve upon the aforementioned problems of the prior art have been proposed (Patent Documents 1 and 2).

[0009] Patent Document 1 discloses a method for manufacturing fiber-reinforced plastic in the form of ribs by stacking at least two prepreg substrates with inserted slits and adjusted fiber lengths of 10 to 100 mm, and then pressing them together. However, even with prepreg substrates having inserted slits, the elongation of the substrate and the flowability of the fibers differ in the fiber direction and in the direction perpendicular to the fibers. Therefore, depending on the shape of the fiber-reinforced plastic and the ribs, "unfilled" portions (where no fibers or resin are filled) and "resin enrichment" (where only resin is extruded from the prepreg) may sometimes occur in the rib portion of the mold.

[0010] Furthermore, Patent Document 2 illustrates a situation where, in fiber-reinforced plastics formed from a laminate of fabric prepreg and discontinuous fiber prepreg, a fiber-reinforced plastic with less fabric mesh disorder can be obtained when the heat of resin generation in each prepreg meets specified conditions. However, by first curing the fabric prepreg disposed on the designed surface, insufficient resin flow can lead to fly-off, pinholes, and sometimes damage to surface smoothness and appearance quality.

[0011] Existing technical documents Patent documents Patent Document 1: International Publication No. 2008 / 038429 Patent Document 2: International Publication No. 2019 / 031111 Summary of the Invention

[0012] The problem that the invention aims to solve The purpose of this invention is to improve upon the problems of the prior art and provide a lightweight fiber-reinforced plastic with protrusions that has excellent mechanical properties and appearance.

[0013] Methods for solving problems The present invention, which achieves the above objectives, is described in any of the following descriptions.

[0014] (1) A fiber-reinforced plastic formed of a shape having a plate-like portion and at least one protrusion raised from at least one side of the plate-like portion, wherein the plate-like portion has at least one layer of multiple reinforcing fibers arranged unidirectionally in a matrix resin (unidirectional layer), wherein the protrusion extends in at least two different directions, and at least two of the directions in which the protrusion extends are not parallel and not perpendicular to each other, and all the directions in which the protrusion extends are not parallel and not perpendicular to the fiber orientation direction in any of the unidirectional layers of the plate-like portion.

[0015] (2) The fiber-reinforced plastic as described in (1) above, having at least one unidirectional layer in which the fiber orientation direction is neither parallel nor perpendicular to all directions in which the aforementioned protrusion extends.

[0016] (3) The fiber-reinforced plastic as described in (1) or (2) above, wherein the plate-like portion has at least two unidirectional layers, the fiber orientation directions of the two unidirectional layers being non-parallel to each other.

[0017] (4) The fiber-reinforced plastic as described in any one of (1) to (3) above, wherein the plate-like portion has at least two unidirectional layers, the fiber orientation directions of the two unidirectional layers being perpendicular to each other.

[0018] (5) The fiber-reinforced plastic as described in any one of (1) to (4) above, wherein the angle formed by all directions of the aforementioned protrusions and the fiber orientation direction in any unidirectional layer of the aforementioned plate-like portion is 15° to 80° or 100° to 165°.

[0019] (6) The fiber-reinforced plastic as described in any one of (1) to (5) above, wherein the fiber unit area weight of at least one of the aforementioned unidirectional layers located inside the aforementioned plate-like portion is 70 g / m². 2 Above, 200g / m 2 the following.

[0020] (7) The fiber-reinforced plastic as described in any one of (1) to (6) above, wherein at least one of the aforementioned unidirectional layers located inside the aforementioned plate-shaped portion comprises reinforcing fibers with a fiber length of 10 to 300 mm.

[0021] (8) The fiber-reinforced plastic as described in any one of (1) to (7) above, wherein the interior of the aforementioned plate-shaped portion has two or more of the aforementioned unidirectional layers with different fiber unit area weights.

[0022] (9) The fiber-reinforced plastic as described in (8) above, wherein the outermost layer on the protrusion side of the plate-shaped portion is a unidirectional layer, and the fiber unit area weight of the outermost unidirectional layer is less than the fiber unit area weight of at least one other unidirectional layer in the plate-shaped portion.

[0023] (10) The fiber-reinforced plastic as described in any one of (1) to (9) above, wherein the plate-shaped portion has multiple layers formed of reinforcing fibers and matrix resin, the protrusion is only on one side of the plate-shaped portion, and at least one of the layers other than the outermost layer of the side with the protrusion is a layer (non-unidirectional layer) in which multiple reinforcing fibers are oriented in at least two directions in the matrix resin.

[0024] (11) The fiber-reinforced plastic as described in any one of (1) to (10) above, wherein the plate-shaped portion has multiple layers formed of reinforcing fibers and matrix resin, the aforementioned protrusion is only on one side of the plate-shaped portion, and the aforementioned reinforcing fibers forming the outermost layer of the opposite side of the one-sided surface are fabric.

[0025] (12) A method for manufacturing fiber-reinforced plastic, wherein at least one layer of prepreg blank, in which a matrix resin is impregnated to a plurality of reinforcing fibers arranged in a unidirectional manner, is placed in a mold, the mold is closed and heated and pressurized to obtain the fiber-reinforced plastic as described in any one of (1) to (11).

[0026] Invention Effects According to the present invention, it is possible to provide a lightweight fiber-reinforced plastic with protrusions that has excellent mechanical properties and appearance quality. Attached Figure Description

[0027] Figure 1 A conceptual diagram illustrating an example of protrusions and plate-like portions in fiber-reinforced plastics.

[0028] Figure 2 A conceptual diagram illustrating examples of protrusions extending in different bidirectional directions.

[0029] Figure 3 An explanatory diagram illustrating the definitions of fiber length inserted into the prepreg blank, and the respective definitions of the length, angle, and projected length of the cut.

[0030] Figure 4 An example of a cutting pattern for inserting the cut into the prepreg blank (an example with parallel and continuous cuts).

[0031] Figure 5 Other examples of cutting patterns for inserting slits into prepreg blanks (examples with parallel and discontinuous slits).

[0032] Figure 6 Other examples of cutting patterns for inserting slits into prepreg blanks (examples with a constant angle to the reinforcing fiber and approximately half positive and half negative slits).

[0033] Figure 7 Other examples of cutting patterns for inserting slits into prepreg blanks (examples where the shortest distance between adjacent slits is longer than the length of the slit).

[0034] Figure 8 A schematic diagram showing the presence and height of mesh distortion in the surface of fiber-reinforced plastic (the side opposite to the side with the protrusions).

[0035] Figure 9 A conceptual diagram illustrating the orientation of reinforcing fibers in the protrusions and plate-like portions that constitute fiber-reinforced plastics.

[0036] Figure 10 A schematic diagram illustrating an example of the shape of a protrusion rising from a plate-like portion.

[0037] Figure 11 A diagram illustrating a molded body with Y-ribs manufactured using a mold with Y-shaped rib grooves.

[0038] Figure 12 A diagram illustrating a molded body with X-ribs manufactured using a mold with X-rib grooves.

[0039] Figure 13This is a schematic diagram of the fiber-reinforced plastic with H-shaped protrusions formed in the embodiment.

[0040] Figure 14 This is a schematic diagram of the fiber-reinforced plastic with V-shaped protrusions formed in the embodiment.

[0041] Figure 15 This is a schematic diagram of the fiber-reinforced plastic with "ハ"-shaped protrusions formed in the embodiment. Detailed Implementation

[0042] The fiber-reinforced plastic of the present invention has at least one layer (hereinafter sometimes referred to as a unidirectional layer) in which multiple reinforcing fibers are arranged in a matrix resin in a unidirectional manner, for example, as shown in the figure. Figure 2 As shown, it consists of a plate-shaped portion 100 and at least one ( Figure 2 The fiber-reinforced plastic is formed from a protrusion (at locations a and b) that rises from at least one side of the plate-like portion 100. In this invention, the protrusion extends in at least two different directions. Hereinafter, the directions in which the protrusion extends will be described.

[0043] The shape of the protrusion when viewed from above the surface of the plate-like portion is defined as the planar shape of the protrusion. The direction in which this planar shape extends is defined as the direction of extension of the protrusion (hereinafter, sometimes also referred to as the length direction). The direction perpendicular to the length direction in this planar shape is defined as the width direction of the protrusion. Here, the direction of extension of the planar shape refers to the major axis direction when the planar shape is elliptical, the long side direction when the planar shape is rectangular, and the long side direction of the rectangle with the smallest area circumscribed by the shape when the planar shape is otherwise. Furthermore, a cross section that is parallel to the length direction of the protrusion and perpendicular to the planar direction of the plate-like portion, where the length direction of the protrusion is maximized, is called the cross section of the protrusion. A cross section that is parallel to the width direction of the protrusion and perpendicular to the planar direction of the plate-like portion, where the width direction of the protrusion is maximized, is called the longitudinal section of the protrusion. As an example, when the planar shape of the protrusion is... Figure 1 In the case of such an ellipse, the major axis direction of the ellipse becomes the length direction 20 of the protrusion, the minor axis direction becomes the width direction 21 of the protrusion, the cross section perpendicular to the plane direction of the plate-like part along the major axis becomes the cross section 22 of the protrusion, and the cross section perpendicular to the plane direction of the plate-like part along the minor axis becomes the longitudinal section 23 of the protrusion.

[0044] In this invention, the protrusion extends in at least two different directions. That is, as an example, such as... Figure 2As shown, a protrusion refers to a protrusion having two or more protrusions extending in different directions, or a planar shape (such as an X-shape, V-shape, H-shape (excluding those where all directions of extension are perpendicular or parallel), or a Y-shape, etc.) that can be obtained by combining two or more planar shapes extending in different directions. That is, for example, it can be interpreted as having two length directions when the planar shape of the protrusion is X-shaped or V-shaped, and three length directions when it is H-shaped or Y-shaped. Based on this, the aforementioned planar shape is decomposed into multiple shapes, and interpreted as having multiple cross-sections and longitudinal sections corresponding to each direction.

[0045] In this invention, the at least two different directions in which the protrusion extends are neither parallel nor perpendicular to each other. Here, "neither parallel nor perpendicular" means that when any one direction is set to 0°, the other directions are not 0° or 90°.

[0046] Furthermore, the fiber-reinforced plastic of the present invention is characterized in that the plate-like portion has at least one layer (unidirectional layer) in which multiple reinforcing fibers are arranged unidirectionally in the matrix resin. The aforementioned unidirectional layer may constitute the portion corresponding to the plate-like portion, and may be either the surface layer or an inner layer portion thereof. It should be noted that, in the present invention, the material equivalent to the unidirectional layer before molding the fiber-reinforced plastic is referred to as a unidirectional prepreg preform.

[0047] In this invention, all directions in which the protrusion extends are neither parallel nor perpendicular to the fiber orientation direction in any of the unidirectional layers of the aforementioned plate-like portion (i.e., neither parallel nor perpendicular). In other words, the above requirement refers to having a unidirectional layer with respect to each direction in which the fiber orientation direction is neither parallel nor perpendicular. For example... Figure 2 As an example, if the plate-like portion has a unidirectional layer with a fiber orientation direction that is neither parallel nor perpendicular to the direction in which the protrusion a extends, and a unidirectional layer with a fiber orientation direction that is neither parallel nor perpendicular to the direction in which the protrusion b extends, then the above requirements are satisfied. Here, even if there is one (or more) unidirectional layers with fiber orientation directions that are neither parallel nor perpendicular to either of the two directions in which the protrusions a and b extend, the above requirements are satisfied, which is one of the preferred methods.

[0048] Furthermore, the statement that "the direction of the protrusion's extension is neither parallel nor perpendicular to the fiber orientation direction of the unidirectional layer" simply means that the fiber orientation direction is inclined relative to the length direction of the protrusion. That is, for example... Figure 9 (A) to (C) show how the reinforcing fibers constituting the unidirectional prepreg extend in the longitudinal direction (rib direction, paper depth direction) or orthogonal to the protrusions, but not in such a manner, but rather as follows: Figure 9As shown in (D), this refers to the way in which the reinforcing fibers are not along the longest direction of the protrusion or the direction orthogonal to it.

[0049] It should be noted that, Figure 9 (A) shows the reinforcing fiber 300 parallel to the longitudinal direction (rib direction) of the protrusion 200. Figure 9 (B) shows the reinforcing fiber 300 perpendicular to the length direction (rib direction) of the protrusion 200, further, Figure 9 (C) shows that the reinforcing fiber 300 is parallel and perpendicular to the longitudinal direction (rib direction) of the protrusion 200. On the other hand, Figure 9 (D) indicates that the cross section of the reinforcing fiber 300 is flat because the length direction (rib direction) of the reinforcing fiber 300 is neither parallel nor perpendicular to the length direction (rib direction) of the protrusion 200.

[0050] When the fiber orientation of the unidirectional layer is parallel to the length direction of the protrusion, the protrusion is unable to withstand shear loads. Therefore, the protrusion lacks strength, and cracks easily penetrate into its interior along the direction of fiber doubling, increasing the likelihood of breakage and detachment from the plate-like portion. Furthermore, when the fiber orientation of the unidirectional layer is perpendicular to the length direction of the protrusion, the reinforcing fibers have difficulty flowing into the interior of the protrusion (the recess in the mold) during molding, increasing the possibility of unfilled areas of reinforcing fibers within the molded protrusion. Additionally, if the reinforcing fibers have difficulty flowing, the possibility of extruding matrix resin from the unidirectional prepreg and creating areas with only resin (resin-rich regions) also increases.

[0051] In contrast, in the final fiber-reinforced plastic, the fact that all directions in which the protrusions extend are neither parallel nor perpendicular to the fiber orientation direction in any unidirectional layer of the plate-like portion (i.e., that at least one unidirectional layer in each extension direction is provided with the fiber orientation direction neither parallel nor perpendicular to the extension direction of the protrusion) means that the number of reinforcing fibers extending throughout each extension direction of the protrusion is reduced. Therefore, according to the present invention, it is possible to suppress... Figure 9 As shown in (A), a 500° depression is formed in the protrusion of the fiber-reinforced plastic along the direction of the fiber strands. Figure 9 The generation of the "unfilled" area 600 of fiber and resin, as shown in (B) and (C), and the generation of "resin enrichment", not only improve mechanical properties such as strength, but also improve appearance quality.

[0052] It should be noted that, in this invention, any unidirectional layer in which the direction of the protrusion extending is related to the orientation direction of the reinforcing fiber is acceptable, but it is preferable to have at least one unidirectional layer in which the entire direction of the protrusion extending is related to the orientation direction of the reinforcing fiber. By having such a layer, the fiber filling capacity of the protrusion is improved, and carbon fibers continuous with the plate-like portion are filled into the interior of each rib, resulting in a molded product with excellent mechanical properties.

[0053] Furthermore, in this invention, by extending the protrusions themselves in two or more different directions and arranging these protrusions so that they are neither parallel nor perpendicular to each other, even when unidirectional layers are individually stacked in the plate-shaped portion with the fiber orientation direction (°) being [0 / 90], the fiber orientation direction within the plate-shaped portion can be neither parallel nor perpendicular relative to the extension direction of the protrusions. Therefore, the width of the stacked structure is increased, and a molded article with protrusions that has excellent mechanical properties and excellent appearance quality can be obtained.

[0054] In this invention, the plate-like portion having at least two unidirectional layers, wherein the fiber orientation directions of the two unidirectional layers are perpendicular to each other, is one of the preferred embodiments. For example, a laminated structure corresponding to fiber orientation directions (°) of [+45 / -45], [+30 / -60], [+50 / -40], etc., is preferred, but is not particularly limited to these. Furthermore, as a whole, the laminated structure having a symmetrical laminated structure can reduce the warpage of the plate-like body (fiber-reinforced plastic) itself, and is therefore preferred.

[0055] It should be noted that the angle between the fiber orientation direction and the length direction (extension direction) of the protrusion (the angle formed by the orientation direction of the reinforcing fiber and the length direction of the protrusion) is not particularly limited as long as it is neither parallel nor perpendicular, but is preferably 15° to 80° or 100° to 165°. That is, within 0 to 90°, 15° to 80° is preferred. Furthermore, from the viewpoint of filling properties of the protrusion and the bonding strength between the protrusion and the plate-like portion, within 0 to 90°, 20° to 70° is more preferred, and 30° to 60° is even more preferred.

[0056] Details of the plate-like portions and protrusions will be described later, but they can be obtained, for example, by preparing multiple unidirectional prepreg blanks, sequentially stacking these fibers in the desired direction, and then pressing the laminate (preform). Furthermore, when manufacturing the laminate (preform), it can be shaped in a predetermined manner as needed. Then, the laminate is placed into a preheated mold (e.g., a concave mold) and molded by heating and pressing using a press, thereby obtaining fiber-reinforced plastic.

[0057] The shape of the plate-like portion is not particularly limited. The thickness can be arbitrarily designed by adjusting the amount of fiber and matrix resin used. As a method to adjust the amount of fiber and matrix resin used, in addition to adjusting the number of layers of the unidirectional prepreg, it is also possible to arbitrarily adjust the amount of resin impregnated in the unidirectional prepreg, change the type of fiber, etc.

[0058] When the fiber-reinforced plastic of the present invention is used in structural components, outer panels such as covers, and other parts in vehicles such as automobiles and motorcycles, bicycles, sports equipment such as golf clubs, and medical devices, the thickness of the plate-like portion is preferably 0.1 to 10 mm from the viewpoint of simultaneously achieving the required mechanical properties and lightweighting, as well as practicality. More preferably, it is 0.3 to 1.8 mm, and even more preferably, it is 0.5 to 1.2 mm. Particularly when used in applications requiring lightweighting, it is preferably 0.5 to 1.2 mm.

[0059] Regarding the shape of the protrusions raised from the plate-like portion, as described above, there are no particular limitations as long as they extend in at least two different directions, and at least two of these directions are neither parallel nor perpendicular to each other; various shapes can be adopted depending on the purpose. For example, the shape observed from the upper surface of the plate-like portion, in addition to... Figure 10 The Y-shape shown in (A) Figure 10 The X-shape shown in (B) Figure 10 The H-shape shown in (C) and Figure 10 In addition to the V-shaped protrusion shown in (D), protrusions of polygonal shapes and the like can also be cited. Furthermore, they can be combined.

[0060] It should be noted that, as mentioned above, when a protrusion has a planar shape that can be formed by combining two or more planar shapes extending in different directions, it is understood that the protrusion has two or more different extending directions. For example, in a case where... Figure 10 In the case of the Y-shaped planar protrusion in (A), it is interpreted as the protrusion extending along the three directions of extension direction 203, extension direction 204, and extension direction 205. Furthermore, in this invention, the following is employed... Figure 10 In the case of the protrusion of (A), in the plate-shaped portion, it is sufficient to have a unidirectional layer whose extension direction 203 is neither parallel nor perpendicular to the fiber orientation direction, a unidirectional layer whose extension direction 204 is neither parallel nor perpendicular to the fiber orientation direction, and a unidirectional layer whose extension direction 205 is neither parallel nor perpendicular to the fiber orientation direction. At this time, any two of the above three unidirectional layers can be the same unidirectional layer, or all of them can be the same unidirectional layer.

[0061] The cross-sectional shape and longitudinal shape of the protrusion can be, for example, polygonal (e.g., rectangular), triangular, or semi-circular.

[0062] Regarding the cross-sectional shape and height of the protrusion, although it is possible to set all of the multiple protrusions to have the same shape and size, it is also possible to vary them according to the concave and convex shape and curvature shape of the fiber reinforced plastic, and it is also possible to partially manufacture parts that are not in the aforementioned shape and size ratio.

[0063] In the fiber-reinforced plastic of the present invention, the height of the protrusion ( Figure 1 Reference numeral 3) in the attached figures is not particularly limited and can be designed arbitrarily, but is preferably 0.1 to 50 mm. If the height of the protrusion exceeds 50 mm, there is a possibility that an unfilled portion of the unidirectional prepreg blank will not be filled to the front end of the protrusion. Furthermore, if the height of the protrusion is less than 0.1 mm, the required rigidity of the molded article will be lower, and there is a possibility that the required mechanical properties cannot be obtained. The height of the protrusion is more preferably 0.1 to 20 mm, further preferably 1 to 10 mm, and most preferably 0.1 to 5 mm.

[0064] On the other hand, the width of the protrusion ( Figure 1 The reference numeral 1) in the attached figures is not particularly limited and can be designed arbitrarily according to the required strength and design. It should be noted that from the point of view of lightweighting, a narrower portion is preferred, but from the perspective of reinforcing the plate-like portion, for example, a width of 0.5 to 8 mm relative to the thickness of the plate-like portion (0.1 to 1.8 mm) is preferred. Further preferred is 0.5 to 3 mm, and most preferred is 0.5 to 1.5 mm.

[0065] In the fiber-reinforced plastic of the present invention, protrusions can be disposed at any position on the plate-like portion. Furthermore, the placement position of the protrusions can be confirmed during top-view observation of the entire fiber-reinforced plastic, allowing for a clear assessment of the appearance of the protrusions. The protrusions can be disposed at two or more locations. That is, protrusions of the same or different shapes can be provided at two or more locations.

[0066] It should be noted that, in terms of the number of protrusions, when viewed from above, the parts that are visible as plate-like portions are considered not to be protrusions. The smallest protrusion surrounded by the plate-like portion is identified as an independent protrusion and counted.

[0067] When ribs are provided as protrusions, in order to simultaneously achieve the lightweighting and increased rigidity of the fiber-reinforced plastic as described in this invention, it is preferable to provide ribs at two or more locations, not just one. This expands the reinforcement range of the plate-like portion. Furthermore, with ribs provided at two or more locations, the ribs can be provided discontinuously and intermittently.

[0068] The fiber-reinforced plastic of the present invention is characterized in that, as described above, it is formed by a unidirectional prepreg blank in which at least one layer of multiple reinforcing fibers are arranged sequentially in a unidirectional direction within at least the interior of the plate-like portion, and the fiber orientation direction of any unidirectional prepreg blank is neither parallel nor perpendicular to the directions in which the protrusion extends. Here, "the interior of the plate-like portion" can refer to the portion corresponding to the plate-like portion, which may be the portion constituting the surface layer or the inner layer portion outside of it.

[0069] When two or more unidirectional prepreg layers are stacked, it is preferable that the fiber orientation directions of the layers are perpendicular to each other. That is, it is preferable that the plate-like portion has at least two of the aforementioned unidirectional layers, and the fiber orientation directions of these two unidirectional layers are perpendicular to each other. By making the fiber orientations of the layers perpendicular, the warpage and twisting of the resulting molded article can be reduced. Furthermore, since warpage and twisting can be reduced, the process effect of reducing warpage and twisting of the molded article can also be achieved. It should be noted that the relationship between the layers can be freely set according to the desired properties of the composite material, and a non-perpendicular arrangement is not excluded.

[0070] While the stacking order of unidirectional prepreg blanks can be arbitrarily set, from a formability perspective, it is preferable to stack layers that are neither parallel nor perpendicular to the length direction of the protrusions, placing them close to the protrusions. Preferably, in the plate-like portion, it is ideal to place the unidirectional prepreg blanks up to the fourth layer from the surface with the protrusions; most preferably, it is ideal to place the unidirectional prepreg blanks on the outermost layer of the surface with the protrusions. Furthermore, it is also preferable to arrange all layers from the outermost layer of the surface with the protrusions up to the second layer, and further from that outermost layer up to the fourth layer, as layers that are neither parallel nor perpendicular to the length direction of the protrusions.

[0071] Furthermore, the number of layers in the unidirectional prepreg can be increased. The more layers the unidirectional prepreg has, the more fibers flow towards the protrusions, which is therefore preferred. Preferably, there are 4 or more layers, more preferably 6 or more layers. By laminating in this way, the reinforcing fibers can easily flow towards the protrusions, and the reinforcing fibers can be easily filled to the ends of the protrusions, which is preferred from the viewpoint of formability and the mechanical properties of the protrusions.

[0072] While unidirectional prepregs can be configured such that at least the fiber orientation direction satisfies the aforementioned arrangement, in this invention, a preferred configuration is one where at least a portion of the plate-like portion has a structure formed by stacking two or more layers of unidirectional prepregs, and the fiber directions (fiber orientation directions of the unidirectional layers) of the reinforcing fiber layers of any two randomly selected unidirectional prepregs are not parallel to each other. Specifically, it is preferable to have a structure with at least two layers of reinforcing fibers arranged unidirectionally, and the orientation directions of the reinforcing fibers in any two randomly selected layers are not parallel to each other. When the orientation direction of the reinforcing fibers is only unidirectional, the protrusions are prone to warping due to the anisotropy of thermal shrinkage and linear expansion coefficients, resulting in poor dimensional accuracy. Furthermore, when the protrusions are ribs, the durability of the ribs against external forces cannot be improved when bidirectional forces or torsional forces act on them.

[0073] It should be noted that when multiple unidirectional layers (reinforcing fiber layers) with different fiber orientations are stacked, the angle (°) of the fiber orientation direction is usually taken as [0 / 90]n. S Such symmetrical stacking becomes [0 / ±60]n S [+45 / 0 / -45 / 90]n S Such isotropic lamination, and the symmetrical lamination structure relative to the lamination direction (thickness direction), is effective in reducing warpage of the plate-like portion of the fiber-reinforced plastic. On the other hand, in the fiber-reinforced plastic of the present invention, since warpage can be reduced by making the protrusions rib-shaped, the orientation direction of the fibers can be biased towards the rigidity direction required by the fiber-reinforced plastic.

[0074] Furthermore, in this invention, in at least one unidirectional layer within the plate-like portion (particularly the outermost unidirectional layer on the protrusion side), the fiber length of the reinforcing fiber is preferably set to 10–300 mm. By keeping the fiber length within this range, the reinforcing fiber can easily follow the shape of the protrusion of the molded article, improving the shaping ability of the three-dimensional shape. Moreover, since the disorder of fiber arrangement during shaping and molding is reduced, fiber-reinforced plastics with small deviations in mechanical properties and high surface smoothness can be obtained.

[0075] Specifically, by setting the fiber length to less than 300 mm, the flexibility and flowability of the fibers are improved, resulting in excellent shapeability and moldability. On the other hand, if the fiber length is set to more than 10 mm, the distance between the cuts makes it difficult for cracks generated when the fiber-reinforced plastic is subjected to high loads to connect, thus resulting in a fiber-reinforced plastic with high mechanical properties and durability.

[0076] It should be noted that when adjusting the fiber length by cutting the reinforcing fibers with a cutting tool, the reinforcing fibers may move when the cutting tool touches them, potentially resulting in fibers escaping from the tool or being caught in it. Therefore, it is believed that there may be fibers outside the aforementioned range. However, by adjusting the fiber length of most reinforcing fibers to the aforementioned range, a sufficient improvement is expected. Furthermore, since there are also fibers that are cut off during molding due to contact with the edge of the mold, there may sometimes be fibers shorter than the aforementioned range inside the molded product.

[0077] Regarding the fiber length of the reinforcing fibers, although the fiber length of all the reinforcing fibers in the fiber-reinforced plastic can be adjusted to the aforementioned range, even adjusting only the fiber length of the reinforcing fibers around the protrusions and other parts of the fiber-reinforced plastic that have shape changes can achieve sufficient results.

[0078] As a method of using a unidirectional prepreg blank with reinforcing fibers of 10 to 300 mm in length arranged unidirectionally, which can be used in this invention, for example, it can be (1) impregnating a matrix resin into a reinforcing fiber sheet obtained by spinning discontinuous reinforcing fibers obtained by spinning means such as draw-spinning; it can also be (2) impregnating a matrix resin into a reinforcing fiber sheet obtained by spinning discontinuous reinforcing fibers (e.g., chopped fibers) unidirectionally arranged unidirectionally; or it can also be (3) on the entire surface of a unidirectional prepreg blank composed of continuous reinforcing fibers, for example, Figures 3-7 As shown, insert a continuous or discontinuous finite length cut along the direction of the reinforcing fiber (the cut is inserted into the prepreg blank).

[0079] (1) The so-called draw-cut spinning is a textile method in which tension is applied to continuous fibers in a bundle state, thereby cutting the fibers into short fiber units. It is characterized by the short fiber cutting points not being concentrated in one place but being evenly distributed throughout the entire length of the bundle. It is a method of forming an aggregate by randomly arranging the cut ends of the reinforcing fibers into individual fiber units, rather than aligning them. Although the reinforcing fibers have slightly poorer formability due to flowing in individual fiber units, stress transfer is very efficient, resulting in extremely high mechanical properties. Furthermore, because the cut parts of the reinforcing fibers are dispersed, excellent quality stability can be achieved.

[0080] (2) The method of sheeting discontinuous reinforcing fibers (e.g., chopped fibers) by unidirectional arrangement is to align the cut ends of the reinforcing fibers in multiple fiber units and arrange them in a certain degree of regularity to form an assembly. Since the arrangement and distribution of reinforcing fibers will inevitably be uneven, the quality stability will be slightly worse, but since the flow is in multiple fiber units, excellent formability can be achieved.

[0081] (3) In the method of inserting the prepreg blank with a cut, the quality stability and mechanical properties are excellent because the reinforcing fibers are regularly arranged, and the formability is also excellent because the fibers flow in units of multiple fibers.

[0082] The above three methods (1), (2), and (3) can be appropriately selected according to the application. They are all methods with excellent balance between mechanical properties and formability and can be easily manufactured. However, the method of (3), which involves inserting a continuous or discontinuous finite length cut along the direction of the reinforcing fibers on the entire surface of the unidirectional prepreg blank made of continuous reinforcing fibers, is the most preferred.

[0083] It should be noted that there are no particular limitations on the method of inserting the prepreg blank into the notch. For example, it is feasible to insert the notch manually using a cutter, but it is preferable to use a mechanical method such as an automatic cutting machine that can produce in large quantities and has stable quality. There are no particular limitations on the mechanical method of inserting the notch. For example, methods such as inserting the notch at a predetermined position using a cutting machine that moves a blade on a prepreg blank substrate laid out on a worktable; methods that insert the notch by rotating a perforated rotary cutter in a straight line, or by scanning a pulsed laser used for laser processing at high speed in a straight line, thereby corresponding to the pulse cycle, etc., are all highly productive notch insertion methods and can be selected according to the available production equipment.

[0084] In the prepreg obtained through the above process, multiple discontinuous cuts are provided along the direction that traverses at least a portion of the reinforcing fibers. As a result, the fiber length of at least a portion of the reinforcing fibers is 10 to 300 mm. Moreover, by using the discontinuous cuts, the reinforcing fibers are substantially all cut off, which ensures shapeability and fiber flowability during molding.

[0085] Regarding the length of the slit, when defined as the projected length Ws on the projection plane perpendicular to the reinforcing fiber within the surface of the prepreg substrate, it is preferably in the range of 30 μm to 1.5 mm. However, since the substrate deforms during molding and forming, the slit may become longer where the substrate extends and shorter where the substrate breaks due to compression. Therefore, when observing the molded fiber-reinforced plastic, although there are areas where the slit length is not within the above range, the presence of a structure in which reinforcing fibers with a final fiber length of 10 to 300 mm are regularly arranged in the fiber-reinforced plastic results in a molded product with excellent mechanical properties and surface appearance.

[0086] By reducing Ws, the amount of reinforcing fibers cut by individual slits is reduced, potentially leading to increased strength. In particular, setting Ws to below 1.5 mm can result in significant strength improvements. On the other hand, when Ws is less than 30 μm, it can be difficult to control the slit position, leading to greater deviations in the length of the reinforcing fibers, an increase in reinforcing fibers of length outside the specified range, and decreased shape retention and flowability.

[0087] Here, the term "projection length Ws projected onto a projection plane perpendicular to the reinforcing fiber" refers to... Figure 3 , 5 As shown in Figures 6 and 7, when the cut is inserted into the surface of the prepreg blank, it is assumed that there is a projection plane in the direction perpendicular to the orientation direction of the reinforcing fiber (fiber perpendicular direction 6), which refers to the length when the cut is projected perpendicularly (along the fiber orientation direction 5) onto the projection plane.

[0088] The angle formed by the cut of the prepreg substrate and the reinforcing fiber is set as θ When, preferred θ The absolute value is in the range of 2 to 25°. By making... θ An absolute value of 25° or less can improve mechanical properties, especially tensile strength. From this perspective, a value of 25° or less is preferable. θ The absolute value is less than 15°. On the other hand, if θ If the absolute value of the angle is less than 2°, it can be difficult to insert the blade stably. That is, if the blade becomes horizontal relative to the reinforcing fiber, the reinforcing fiber can easily escape from the tool during insertion, reducing the positional accuracy of the blade. Considering the above, a more preferable approach is... θ The absolute value is 5° or higher.

[0089] As a method for inserting an incision, it is possible to use, for example... Figure 4 As shown, for example, the method of continuous insertion at the aforementioned angle, and as... Figure 7 Any of the methods shown can be used to intermittently insert multiple slits. With continuous slits, the fiber length can be kept constant, reducing deviations in mechanical properties and three-dimensional shape conformation. On the other hand, with intermittent slit insertion, by tilting the slit angle relative to the reinforcing fiber, the projected length Ws of the prepreg substrate projected onto the plane perpendicular to the reinforcing fiber can be reduced relative to the actual slit length Y. Therefore, extremely small slits, such as Ws = 1.5 mm or less, can be stably set industrially. Furthermore, compared to continuous slits, the prepreg is less prone to becoming scattered during lamination, resulting in superior workability as a prepreg.

[0090] Preferred cutting patterns for inserting the cut into the prepreg blank, such as Figure 5As shown, a plurality of discontinuous inclined cuts 9 can be provided in at least a portion of the prepreg substrate along the direction traversing the reinforcing fibers. The plurality of discontinuous inclined cuts 9 are inserted in a straight line to form columns 11, and more preferably, multiple columns 11 are arranged parallel to each other. By doing so, with the reinforcing fibers of constant length, the distance between adjacent cuts can be maximized, resulting in homogenization of the fiber-reinforced plastic and improved strength. Preferably, the distance X between columns is in the range of, for example, 1 to 5 mm.

[0091] When inserting prepreg blanks into a stack, even if the prepreg blanks are in the same fiber direction, the cut direction will differ depending on whether the prepreg blank is viewed from the surface or the back side, if the inclined cut is only in one direction. Therefore, in manufacturing fiber-reinforced plastics, there is a possibility of increased time spent controlling the cut direction to be the same each time, or increased time spent controlling the same number of lamination steps for materials with the same fiber direction but different cut directions. However, if the absolute values ​​of the slope of the cut from the fiber direction are the same, and the cuts at positive angles and negative angles each make up approximately half of the cutting pattern, then lamination can be performed using the same operation as with conventional continuous fiber prepreg blanks.

[0092] Other preferred cutting patterns for inserting the cut into the prepreg blank include: Figure 6 As shown in the diagram. In this method, at least a portion of the prepreg substrate has a plurality of discontinuous inclined cuts 9 along the direction traversing the reinforcing fibers, and although... θ The absolute value of the inclined cut 9 is essentially the same (uniform), but the angle of the inclined cut 10 is opposite to that of the inclined cut 9. Approximately half of these inclined cuts 9 and 10 are provided. Here, [the text abruptly ends here]. θ The absolute value of "substantially the same" is defined as a deviation within ±1° of the angle. In addition, "approximately half" means that when expressed as a percentage based on the total number of inclined cuts 9 and 10, they are 45% to 55% respectively (the same applies below).

[0093] As a preferred embodiment of inserting the cut into the prepreg blank, such as Figure 6 As shown, when focusing on any one cut A, one can cite among the cuts close to cut A, compared to... θ For the closest incision B with the same positive and negative sign, it is closest to the shortest distance from incision A, and θ There are more than four positive and negative cuts C. When following a three-dimensional shape, for the cut insertion portion of the prepreg blank, the movement of the fiber end is determined by the relationship between the cut angle and the fiber direction. Therefore, by having adjacent cuts of the same shape but opposite angles, isotropy in the plane after molding can be ensured under macroscopic observation.

[0094] Furthermore, as a preferred embodiment for inserting the cut into the prepreg blank, it is also preferable to... Figure 7 As shown, in this method, at least a portion of the prepreg blank is provided with multiple discontinuous inclined cuts 10 along the direction traversing the reinforcing fibers. Furthermore, these discontinuous inclined cuts 10 are inserted in a straight line and of substantially the same length Y, and the shortest distance between adjacent cuts is longer than the length Y of that cut. Here, "substantially the same length" means a difference within ±5% (the same applies hereinafter). From a mechanical point of view, fiber-reinforced plastics fail when cuts, which are points of fiber discontinuity, connect with each other through cracks. By using a cutting pattern where the distance between the cuts is separated within the plane, the effect of at least suppressing crack connection within the same plane is achieved, thus increasing strength.

[0095] Furthermore, as a preferred embodiment of the inserting prepreg blank, a plurality of discontinuous cuts are provided along the direction traversing the reinforcing fibers in at least a portion of the inserting prepreg blank. These discontinuous cuts are inserted in a straight line and of substantially the same length Y, and the distance between adjacent cuts on the same straight line is greater than three times the length Y of the cut. When cuts exist on the same straight line, there is a possibility of damage originating from the cuts occurring along their extension lines, especially as the distance between adjacent cuts increases, making crack formation easier. Therefore, by maximizing the separation of the distance between the same straight-line cuts, crack formation is suppressed, and strength is improved. Moreover, when discontinuous cuts are inserted in the same straight line and the distance between these cuts is close, the cuts are easily identified as a pattern of discontinuous straight lines after molding. On the other hand, by separating the distance between the cuts, they are not identified as a pattern, resulting in a structure with excellent surface quality. It should be noted that the existence of cuts on the same straight line means that the angle between the straight line extending a certain cut and the straight line connecting the closest points of the aforementioned cut and the cut that is the object is within 2°.

[0096] Furthermore, while all unidirectional prepreg blanks can be configured as prepreg blanks with fiber lengths adjusted to the aforementioned range, it is not necessary to arrange reinforcing fibers of the aforementioned fiber lengths in all layers. By utilizing the width, height, curvature, and angle of the protrusions in the fiber-reinforced plastic, the layers in which the unidirectional prepreg blanks with adjusted fiber lengths are arranged can be appropriately selected. That is, even if only the fiber lengths of the reinforcing fibers in, for example, the protrusions of the fiber-reinforced plastic and the reinforcing fibers in the layer directly below the protrusions in the plate-like portion are adjusted, sufficient results can be obtained.

[0097] Regarding the fiber area weight (FAW) of at least the plate-like portion of the fiber-reinforced plastic of the present invention, examples include 50 to 1,000 g / m². 2As an example, but considering deformation resistance and flowability, a value of 50–200 g / m is preferred. 2 Further preferred is 70–200 g / m 2 The optimal value is 70–120 g / m³. 2 When the plate-like portion is composed of two or more layers, it is preferable that at least one layer is within the aforementioned range. Furthermore, in the case of a laminated structure with high fiber weight per unit area, the number of laminated sheets can be reduced. However, by reducing the number of laminated sheets, the fibers on the design surface may flow towards the protrusions, resulting in fiber disorder and a poor appearance. On the other hand, in the case of a laminated structure with low fiber weight per unit area, even with the same molded article thickness, increasing the number of laminated sheets can suppress the flow of fibers on the design surface, resulting in a molded article with a high-quality design appearance.

[0098] The higher the fiber weight per unit area (FAW), the higher the rigidity of the fiber layer, exceeding 1,000 g / m². 2 As deformation resistance increases, fibers struggle to flow into the protrusions (mold recesses), making "unfilled" and "resin enrichment" more likely. Furthermore, when using a cutting tool to cut the fiber insertion slit in a high-weight-per-unit prepreg substrate, an increase in fibers escaping from the tool and the increase in fiber lengths outside the target area significantly increases the likelihood of a prepreg substrate with low flowability. Therefore, prepreg substrates with more layers and lower weight-per-unit prepreg substrates are preferred from a moldability perspective. On the other hand, a fiber weight-per-unit (FAW) of less than 50 g / m² is desirable. 2 In such cases, the cost increases due to the increased production and lamination workload of the prepreg substrate. Furthermore, from the viewpoint of reducing lamination workload, 70 g / m² is further preferred. 2 above.

[0099] When two or more unidirectional prepregs are stacked, two or more types of prepregs with different fiber unit area weights can be used and can be stacked in any order. In other words, there can be two or more unidirectional layers with different fiber unit area weights inside the plate-like portion. For example, when the protrusion is only provided on one surface, it is preferable that the fiber unit area weight of the outermost layer on the protrusion side is less than that of at least one other unidirectional layer. In this way, by placing the easily flowing, low-fiber-unit-area-weight unidirectional prepreg on the protrusion side for molding, and further by placing the difficult-to-flow, high-fiber-unit-area-weight unidirectional prepreg on the design surface side for molding, a molded product with low fiber mesh distortion and high protrusion filling can be obtained. In addition, when the protrusion is on both sides of the plate-like portion, by setting the layers near the protrusion to low fiber unit area weights and setting the middle layers to high fiber unit area weights, both protrusion filling and stacking workload can be achieved simultaneously.

[0100] Preferably, the resin mass fraction (Rc) of the molded article (fiber-reinforced plastic) of the present invention is 10-70%. More preferably, it is 20-60%. When the resin mass fraction (Rc) is less than 10%, the amount of resin on the surface of the molded article is low, and the surface of the molded article becomes uneven due to the unevenness of the fibers. Moreover, the flowability of the fibers also decreases, and "unfilled" products are easily generated during molding. On the other hand, when the resin mass fraction (Rc) exceeds 70%, there is too much resin, and excess resin is generated in the recesses of the molded article ("resin enrichment"), and the smoothness of the surface of the molded article decreases due to the curing shrinkage of the resin.

[0101] In this invention, the reinforcing fiber is not particularly limited, but glass fiber, aramid fiber, polyethylene fiber, silicon carbide fiber, and carbon fiber are preferred. Especially in obtaining lightweight fiber-reinforced composite materials with high performance and excellent mechanical properties, glass fiber and carbon fiber are preferred. Furthermore, glass fiber or carbon fiber can be used alone, or both can be used simultaneously to balance performance and cost.

[0102] Here, there is no particular limitation on the glass fiber, but E glass fiber, S glass fiber, C glass fiber, and D glass fiber are preferred. From the point of view of balancing cost and strength, E glass fiber is preferred, S glass fiber is preferred when high strength is required, C glass fiber is preferred when acid resistance is required, and D glass fiber is preferred when low dielectric constant is required.

[0103] There is no particular limitation on the average fiber diameter of the glass fiber, but the average fiber diameter is preferably 4 to 20 μm, and more preferably 5 to 16 μm. Generally, a diameter of 4 μm or more can achieve sufficient effect, while an average fiber diameter exceeding 20 μm tends to result in a decrease in strength.

[0104] Furthermore, pretreating glass fibers with coupling agents such as isocyanate compounds, organosilane compounds, organotitanate compounds, organoborane compounds, and epoxy compounds is preferred for achieving superior mechanical strength.

[0105] There are no particular limitations on the type of carbon fiber, but polyacrylonitrile-based carbon fiber, rayon-based carbon fiber, and pitch-based carbon fiber are preferred. Among these, polyacrylonitrile-based carbon fiber with high tensile strength is particularly preferred. As for the form of carbon fiber, twisted yarn, untwisted yarn, and untwisted yarn can be used.

[0106] Preferably, the tensile modulus of the aforementioned carbon fiber is in the range of 180 to 600 GPa. If the tensile modulus is within this range, the resulting fiber-reinforced plastic can be made rigid, thus enabling the resulting molded article to be lightweight. Furthermore, generally speaking, the higher the elastic modulus of carbon fiber, the lower its strength tends to be; if it is within this range, the strength of the carbon fiber itself can be maintained. More preferably, the elastic modulus is in the range of 200 to 440 GPa, and even more preferably in the range of 220 to 300 GPa. Any combination of the above upper and lower limits is acceptable. Here, the tensile modulus of the carbon fiber is a value measured according to JIS R7608-2007.

[0107] It should be noted that the following products are examples of commercially available carbon fiber products, but are not specifically limited to these. Examples include "Torayca (registered trademark)" T300, "Torayca (registered trademark)" T300B, "Torayca (registered trademark)" T400HB, "Torayca (registered trademark)" T700SC, "Torayca (registered trademark)" T800HB, "Torayca (registered trademark)" T800SC, "Torayca (registered trademark)" T830HB, and "Torayca (registered trademark)" T1000GB-. The following are examples of trademarks: "Torayca (registered trademark)" T1100GC, "Torayca (registered trademark)" M35JB, "Torayca (registered trademark)" M40JB, "Torayca (registered trademark)" M46JB, "Torayca (registered trademark)" M55J, "Torayca (registered trademark)" M60JB, "Torayca (registered trademark)" M30SC (all manufactured by Toray Industries, Inc.), and PX35 (manufactured by ZoLTEK Corporation).

[0108] Furthermore, when using fabrics with the fiber-reinforced plastic of the present invention as described below, the number of filaments of the reinforcing fibers, carbon fibers constituting the fabric, is not particularly limited. From the viewpoints of weaving productivity, the required tensile and flexural modulus of elasticity, strength, and designability of the fiber-reinforced plastic, a range of 1,000 to 70,000 filaments is preferred, and 1,000 to 60,000 filaments is more preferred. By forming multifilaments by combining multiple filaments, softness can be obtained, and they can be easily deformed into any shape through molding. In addition, for multifilaments, since the shortcomings of a single fiber can be compensated by other fibers, deviations in the mechanical properties of the molded article can be suppressed, and stable performance can be obtained.

[0109] Next, the matrix resin in combination with the aforementioned reinforcing fibers constituting the fiber-reinforced plastic of the present invention will be described. It is preferable to use a thermosetting resin or a thermoplastic resin as the main component of the matrix resin.

[0110] Here, the thermosetting resin that is the main component of the matrix resin can be a heat-curing resin or a resin containing a curing agent, a curing accelerator, etc. A resin that forms at least a partial three-dimensional cross-linked structure by inducing a cross-linking reaction with heat is preferred, but there is no particular limitation. Examples of thermosetting resins include epoxy resin compositions, vinyl ester resin compositions, unsaturated polyester resin compositions, polyurethane resin compositions, benzoxazine resin compositions, phenolic resins, urea resin compositions, melamine resin compositions, and polyimide resin compositions, which are preferred from an operability point of view. Among these, epoxy resin compositions, vinyl ester resin compositions, and unsaturated polyester resin compositions are more preferred from the viewpoint of the performance and environmental resistance of fiber-reinforced plastics. Furthermore, the thermosetting resin composition containing these resins does not necessarily have to be a single type; the resin compositions can be mixed with each other.

[0111] Furthermore, a matrix resin composition can be prepared by dispersing the thermoplastic resin as particles or fibers in a thermosetting resin, or by dissolving the thermoplastic resin in a thermosetting resin and then blending them. For the thermoplastic resin used in this way, it is generally preferred to have a thermoplastic resin having bonds selected from carbon-carbon bonds, amide bonds, imide bonds, ester bonds, ether bonds, carbonate bonds, urethane bonds, thioether bonds, sulfonyl bonds, and carbonyl bonds, even if it partially has a cross-linked structure.

[0112] On the other hand, there is no particular limitation on the thermoplastic resin that is the main component of the matrix resin. From the viewpoints of processability, mechanical properties and design, it is preferable to use a PC / ABS resin obtained by blending polymethyl methacrylate (PBSMMA) resin, polyurethane (TPU) resin, polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, acrylonitrile butadiene styrene (ABS) resin, polyamide (PA) resin (especially PA6, PA66, PA12), polycarbonate (PC) resin, and acrylonitrile butadiene styrene (ABS) resin.

[0113] Here, when coloring is required as one of the design features of fiber-reinforced plastics, there are no particular restrictions on the color. However, by coloring the aforementioned thermoplastic resins with black, red, yellow, green, blue, purple, brown, etc., the design features can be improved.

[0114] In this invention, in order to designate at least one of the layers other than the outermost layer of the surface with protrusions as a non-unidirectional layer, a non-unidirectional reinforcing fiber sheet with reinforcing fibers oriented in at least two directions can be used with the aforementioned unidirectional prepreg blank.

[0115] The aforementioned fibers can be used as reinforcing fibers constituting the non-unidirectional reinforcing fiber sheet, but it is preferable that at least a portion of them include fibers other than thermoplastic resin fibers. When manufacturing the fiber-reinforced plastic of the present invention, heating and pressure molding are performed. However, since thermoplastic resin fibers become soft due to heat, by making at least a portion of the reinforcing fibers constituting the non-unidirectional reinforcing fiber sheet a fiber other than thermoplastic resin fibers, deviations in the thickness and shape of the molded article can be suppressed.

[0116] As a form of non-unidirectional reinforcing fiber sheet, fabric is preferred, for example. Specifically, when the fiber-reinforced plastic of the present invention has protrusions only on one side of the plate-like portion, it is preferably arranged as a fabric as the reinforcing fiber forming the outermost layer on the opposite side. For fabrics woven in with warp and weft yarns, they are used not only because of their excellent mechanical properties and morphological durability, but also to enhance design by revealing the texture of the fabric. It should be noted that the same reinforcing fibers as those in other layers can be used in the fibers constituting the fabric, but different fibers can also be used.

[0117] The weave structure and density of the fabric are not particularly limited and can be arbitrarily chosen from the perspective of fiber-reinforced plastic design. Examples of weave structures include plain weave, twill weave, satin weave, double plain weave, square plain weave, honeycomb weave, float weave, die-cast weave, and crepe weave. Examples of twill weaves include 3-ply twill, 4-ply twill, 5-ply twill, 6-ply twill, stepped twill, curved twill, broken twill, side-ribbed twill, herringbone twill, reed twill, double twill, spiral twill, checkered single-sided twill / twill checkered weave, fancy twill, and shaded twill. Examples of satin weaves include 5-end satin, 7-end satin, 8-end satin, 10-end satin, modified satin, varied satin, reinforced satin, granite weave, satin checkered fabric / satin checkered, and shaded satin. Examples of double plain weaves include warp double plain weave, weft double plain weave, and modified double plain weave. As a planar fabric, examples include regular planar fabric, modified planar fabric, irregular planar fabric, partitioned planar fabric, and triaxial fabric with fibers woven in three directions.

[0118] The reinforcing fibers constituting the fabric can be single glass fibers as exemplified above, or single carbon fibers, or combinations of different glass fibers and carbon fibers. Furthermore, other different reinforcing fibers can be used alone or in combination. In addition, due to its excellent performance, cost, and designability, it is possible to combine at least one type of glass fiber and at least one type of carbon fiber for blending.

[0119] Furthermore, in the outermost layer of fabric, which is formed on the side opposite to the side with the protrusions, it is preferable to pre-impregnate it with a matrix resin. It should be noted that the matrix resin impregnated into the fabric is preferably the same as that used in other layers, but different resins can also be used. When using a resin different from that used in other layers, it is preferable to confirm compatibility and adhesion, and insert an adhesive film or similar material as needed.

[0120] The preferred fiber area weight per unit area of ​​the fabric is 10–300 g / m². 2 More preferably 30–150 g / m 2 The fiber area weight of this fabric is 10 g / m². 2 Under the above conditions, the plastic flow of fibers imparted by the pressure generated during compression molding can be suppressed, and appearance defects such as fiber serpentine and resin enrichment on the surface of the fabric used in the surface layer can be suppressed. Furthermore, the fiber area weight of this fabric is 300 g / m². 2 In the following cases, the material is soft and has excellent shapeability, and when impregnated with epoxy resin compositions or the like during molding, the resin easily reaches the central portion in the thickness direction, leaving little unimpregnated portion (pores). As a result, it becomes a fiber-reinforced plastic exhibiting excellent mechanical properties such as compressive strength.

[0121] Regarding the unit area weight of the prepreg preform into which the matrix resin is impregnated in the fabric, when glass fiber or carbon fiber is used as the reinforcing fiber, it is preferably 20 to 400 g / m². 2 More preferably 40–300 g / m 2 The weight per unit area is 20g / m². 2 Under the above conditions, the weaveability becomes good, and the weight per unit area is 400g / m². 2 In the following cases, the fabric is soft and easy to shape. During the impregnation of the matrix resin (such as an epoxy resin composition) during the manufacturing of the prepreg blank and molding, the resin easily reaches the central part in the thickness direction, and it is not easy for unimpregnated parts (pores) to remain. As a result, it becomes a fiber-reinforced plastic exhibiting excellent mechanical properties such as compressive strength.

[0122] Furthermore, as a non-unidirectional reinforcing fiber sheet, nonwoven fabrics using the aforementioned reinforcing fibers (glass, carbon fiber, etc.) are also preferable. Nonwoven fabrics are preferably used, for example, inside plate-like sections where design is not required.

[0123] The structure and manufacturing method of nonwoven fabrics are not particularly limited. Dry methods, such as carding (where short fibers of a few centimeters are opened and formed into a thin web using a carding machine) or air-forming (where opened short fibers are dispersed by an air random machine and formed into a web on a belt conveyor), are preferred. Furthermore, in the case of nonwoven fabrics manufactured using dry methods, methods that improve the morphological stability of the web by physically interlacing fibers using needle punching, or chemically improving the morphological stability of the web by applying adhesive resins such as unsaturated polyester, polyvinyl alcohol (PVA), or their copolymers using spraying or impregnation, can be used to fix the fibers together. Examples of fiber fixing methods include: blending thermoplastic resin fibers during web manufacturing; and attaching thermoplastic resin particles to the web and then placing the web into a hot roller or oven to melt the thermoplastic resin and fix the fibers together.

[0124] As another example of nonwoven fabric, nonwoven fabrics manufactured using a wet process, in which short fibers are dispersed in water and then scooped onto a papermaking wire, are also preferred. It should be noted that, in order to improve the dimensional stability and workability of nonwoven fabrics manufactured using the wet process in the same way as those manufactured using the dry process, it is also preferable to use a spraying or impregnation method to apply adhesive resins such as unsaturated polyester, polyvinyl alcohol (PVA), or their copolymers to chemically fix the fibers together. During the wire fabric manufacturing process, the fibers are blended with thermoplastic resin, allowing thermoplastic resin particles to adhere to the wire. The wire is then placed in a hot roller or oven to melt the thermoplastic resin, thereby fixing the fibers together.

[0125] In addition to the above-mentioned nonwoven fabrics, nonwoven fabrics manufactured by spunbonding, which involves layering filaments obtained by melt spinning of thermoplastic resin onto a belt conveyor, or nonwoven fabrics manufactured by meltblowing, which involves blowing air into the spun filaments to form fine fibers and then accumulating these fibers on a web, are also preferred due to their excellent mechanical properties and low cost.

[0126] The preferred unit area weight of nonwoven fabric is 10–300 g / m². 2 To absorb the deformation of the prepreg during molding and mitigate its impact on the surface of the molded article, sufficient thickness and strength are required. However, excessive thickness may affect the physical properties of the molded article. Therefore, a thickness of 30–150 g / m² is further preferred. 2 The optimal value is 40–100 g / m³. 2 However, by overlapping nonwoven fabrics with low weight per unit area, it is also possible to adjust to the aforementioned range of weight per unit area.

[0127] When a non-unidirectional reinforcing fiber sheet is provided on the surface of the plate-shaped portion, its thickness is preferably 0.01 to 1.0 mm, more preferably 0.05 to 0.5 mm. When the thickness of the non-unidirectional reinforcing fiber sheet is 0.01 mm or more, it is possible to suppress the plastic flow of fibers imparted by the pressure generated during compression molding, and to suppress undesirable appearances such as the serpentine movement of fabric fibers used in the surface of the plate-shaped portion and resin enrichment in the design surface. On the other hand, when the thickness of the non-unidirectional reinforcing fiber sheet is 1.0 mm or less, it is soft and has excellent shapeability, and when impregnated with epoxy resin composition or the like during molding, the resin easily reaches the central part in the thickness direction, and it is not easy for unimpregnated parts (pores) to remain. As a result, it becomes a fiber-reinforced plastic exhibiting excellent mechanical properties such as compressive strength.

[0128] However, when using nonwoven fabric as a non-unidirectional reinforcing fiber sheet, since the thickness of the nonwoven fabric can be adjusted under the pressure during compression molding, it is preferable to use a nonwoven fabric with a thickness of 0.01 to 3.0 mm.

[0129] Next, a detailed description will be given regarding the manufacturing method of the fiber-reinforced plastics involved in this invention, but the invention is not limited thereto.

[0130] In the case of the fiber-reinforced plastic of the present invention, for example, a unidirectional prepreg blank formed by impregnating a matrix resin with multiple reinforcing fibers can be laminated with the same or different types of unidirectional prepreg blanks, fiber substrates, etc., as needed, and the laminated body can be integrated by heating and pressing as needed through pressure molding, autoclave molding, oven molding, or vacuum oven molding.

[0131] As for molding methods, various molding methods can be mentioned as described above, without particular limitation. However, a preferred method is the pressure molding method, which involves preparing a unidirectional prepreg blank impregnated with a matrix resin, stacking and shaping it as needed, placing it into a mold, and then heating and pressurizing it using a press. As a pressure molding method, by molding under high pressure, the integration of the fiber and the matrix resin is enhanced, and the effects of fiber relaxation and angle deviation can be reduced.

[0132] In pressure molding, the mold cavity (gap) of the die is formed into the desired shape of the fiber-reinforced plastic, and the shape of the die that contacts the protrusions of the fiber-reinforced plastic becomes a recess. As in pressure molding, during thermoforming, the reinforcing fibers and matrix resin can flow into this recess and be molded into the shape of the fiber-reinforced plastic, thus eliminating the need to pre-shape the unidirectional prepreg preform to the same shape as the fiber-reinforced plastic. Therefore, the workload of preform production can be reduced, making it preferable.

[0133] Compared to other molding methods, pressure molding offers overwhelmingly superior productivity due to its simplified pre-molding preparation and post-molding processing. Furthermore, while fiber-reinforced plastics require mold removal after cooling when the base resin is a thermoplastic, they can be demolded even when the mold temperature is substantially constant when the base resin is a thermosetting resin. Therefore, since the mold cooling process required with thermoplastic base resins is eliminated, combining it with fast-curing thermosetting resins can shorten the molding cycle and achieve high productivity.

[0134] It should be noted that the mold temperature T (°C) of the pressure molding is preferably related to the peak heating temperature Tp (°C) of the thermosetting resin based on differential scanning calorimetry (DSC) according to the following formula (I). More preferably, it is also preferred to satisfy the following formula (II).

[0135] Tp-60≤T≤Tp+20···(I) Tp-30≤T≤Tp ···(II) When the mold temperature T (°C) is below Tp-60 (°C), the time required for resin curing becomes very long, and incomplete curing may also occur. On the other hand, when the temperature is above Tp+20 (°C), the rapid reaction of the resin can sometimes cause the formation of internal pores and poor curing. It should be noted that the peak heating temperature Tp (°C) based on DSC is a value measured under a heating rate of 10°C / min.

[0136] The fiber-reinforced plastic of the present invention is preferably manufactured under conditions where the minimum viscosity of the thermosetting resin used as the matrix resin, based on dynamic viscoelasticity (DMA) measurement, is 0.1 to 100 Pa·s. More preferably, it is 0.5 to 10 Pa·s. When the minimum viscosity is less than 0.1 Pa·s, only the resin flows under pressure, and sometimes the reinforcing fibers cannot adequately fill the leading edge of the protrusion. On the other hand, when it is greater than 100 Pa·s, due to insufficient resin flowability, sometimes the reinforcing fibers and resin cannot adequately fill the leading edge of the protrusion. It should be noted that the minimum viscosity based on DMA is a value measured at a heating rate of 1.5 °C / min.

[0137] Furthermore, in this invention, firstly, a unidirectional prepreg blank, which is formed by impregnating a matrix resin with multiple reinforcing fibers, is laminated together with the same or different types of unidirectional prepreg blanks, non-unidirectional reinforcing fiber sheets, or other fiber substrates to form a preform. The preform is then placed in a preheated mold (e.g., a concave mold), and the mold is closed and pressure is applied. Preferably, a fiber-reinforced plastic is obtained by forming a shape having a plate-like portion and at least one protrusion that bulges from at least one side of the plate-like portion. In this case, it is preferable that all directions in which the protrusion extends are neither parallel nor perpendicular to the fiber orientation direction of any unidirectional prepreg blank in the preform.

[0138] As described above, when a unidirectional prepreg blank is combined with other unidirectional prepreg blanks, non-unidirectional reinforcing fiber sheets or fiber substrates, it is also preferable to provide non-unidirectional reinforcing fiber sheets in at least one of the layers from the second layer onwards from the surface of the preform (i.e., the layers other than the outermost layer on the side where the protrusion is provided).

[0139] In particular, when a protrusion is provided on only one side of the plate-shaped portion and a non-unidirectional reinforcing fiber sheet in the form of a fabric is disposed on the outermost layer opposite to the side where the protrusion is provided, it is possible to suppress the plastic flow of fibers caused by the pressure applied during compression molding, and to suppress appearance defects such as fiber serpentination of the fabric fibers used on the surface and resin enrichment on the design surface.

[0140] Non-unidirectional reinforced fiber sheets can be dry sheets without matrix resin, or sheets in the form of prepreg blanks formed by impregnating at least a portion of the matrix resin.

[0141] When the non-unidirectional fiber reinforced sheet is a prepreg blank, the matrix resin pre-impregnated into the non-unidirectional fiber reinforced sheet is preferably the same resin as other prepreg blanks, but from the viewpoint of adhesion and formability, the preferred resin can be arbitrarily selected.

[0142] Furthermore, when the non-unidirectional fiber-reinforced sheet is a prepreg blank, it is preferable that the fiber volume fraction Vf[a] of the non-unidirectional fiber-reinforced sheet and the fiber volume fraction Vf[b] of the aforementioned unidirectional prepreg blank have a relationship of Vf[a] > Vf[b]. In this case, during compression molding, there is room for the matrix resin contained in the unidirectional prepreg blank to impregnate the non-unidirectional fiber-reinforced sheet. That is, by applying pressure during compression molding, the resin contained in the unidirectional prepreg blank can impregnate the unimpregnated portion of the non-unidirectional fiber-reinforced sheet, thereby obtaining a fully resin-filled molded article, and for example, a fiber-reinforced plastic with excellent mechanical properties and a porosity of 2% or less.

[0143] Furthermore, Vf[a] is preferably 55-99.9%, more preferably 80-99%. When Vf[a] is 55% or more, it is less affected by the resin flow caused by the pressure during compression molding, and the fiber flow can be suppressed. Therefore, fiber-reinforced plastics with excellent appearance quality, less fiber disorder, and less surface unevenness can be obtained.

[0144] Example The present invention will be further illustrated below with examples and comparative examples, but the present invention is not particularly limited thereto.

[0145] <Evaluation of the filling properties of fibers and resins into protrusions> [1] Observation of the appearance of the protrusion Visually confirm the presence or absence of "unfilled" areas where neither fiber nor resin is filled, and "resin-rich" areas where only resin is filled.

[0146] [2] Cross-sectional observation of the protrusion All protrusions were cut out using a disc grinder, including the plate-like portion. After grinding the cut surfaces, the interior of the protrusions was observed using a microscope (VHX-6000, manufactured by Keyence Corporation) to confirm the state of the carbon fibers filling the interior.

[0147] The case described in [1] above, where there is no "unfilled" and "resin-rich" carbon fiber filling to the front end of the rib, and the carbon fiber filling to the protrusion in [2] above is continuous with the continuous fiber of the plate-shaped portion (i.e., no "resin-rich" occurs), is evaluated as "A". The case described in [1] above, where there is no "unfilled" and "resin-rich" carbon fiber filling to the front end of the rib, and the carbon fiber filling to the protrusion in [2] above is continuous with the continuous fiber of the plate-shaped portion, but there is a slight local resin accumulation inside (less than 10% of the cross-sectional area of ​​the rib), is evaluated as "B" in the table. All other cases are evaluated as "F".

[0148] <Evaluation of warpage in molded products> Place the plate-shaped part on a flat inspection table (machine) with the protrusion facing upwards, and check the gap (lift) between the end of the plate-shaped part and the inspection table. When the plate-shaped part is in contact with the inspection table on a roughly flat surface, a corner lift of less than 0.7 mm is rated as "A". + The condition is rated "A" for those 0.7mm or more and less than 1mm, and "F" for those 1mm or more.

[0149] <Visual inspection of the design surfaces of the molded part> Hold the upper part of the plate with the protrusion facing down, and visually observe the side of the plate that is opposite to the side with the protrusion (design side) under a fluorescent lamp with an illuminance of 1200 lx (lux).

[0150] At this point, rotate the molded part 360° horizontally, and further observe it while tilting it vertically at an angle of 0° to 60°, checking along the ribs to see if the reflected light from the fluorescent lamp is deformed. A case with no deformation at any angle is rated "A", a case with deformation only at a constant angle is rated "B", and a case with deformation at any angle is rated "F".

[0151] Furthermore, the fiber width was examined for molded fabrics in which reinforcing fibers were used in the surface layer opposite to the side with the protrusion. A case where the fiber width directly below the protrusion was 90% or more of the total fiber width used was rated as "A". ++ The situation where 80% or more but less than 90% is rated as "A". + The system assigns an "A" rating to situations where the percentage is 75% or higher but less than 80%, and an "F" rating to situations where the percentage is less than 75%.

[0152] On the other hand, mesh distortion was confirmed in molded articles where unidirectional prepreg blanks were also used in the surface layer opposite to the side with the protrusions. Regarding the mesh distortion of the fibers located directly below the protrusions, the plane of the fiber-reinforced plastic was visually inspected. Figure 8 The case shown in (B) where the height of the mesh twist 402 is less than 0.3mm is rated as "A". ++ Cases exceeding 0.3 mm but less than 0.6 mm are rated as "A". + Cases exceeding 0.6mm but less than 1.0mm are rated "A", and cases exceeding 1.0mm are rated "F". It should be noted that... Figure 8 In the diagram, (A) represents the normal surface state of mesh distortion without reinforcing fibers, and (B) represents the surface state with mesh distortion.

[0153] [Example 1] Unidirectional prepreg preform #P384-S-7 (carbon fiber (4,900MPa, tensile modulus 235GPa), FAW=70g / m²) manufactured by Toray Industries, Inc. 2 (Thermosetting epoxy resin, Rc=40%), cut 12 pieces from a 100mm×100mm prepreg substrate. Lay them in a [30 / 60]6 manner to prepare a prepreg substrate laminate.

[0154] Next, prepare a 100mm×100mm concave mold as the lower mold. In addition, prepare a groove (rib groove, 1.0mm wide, 40mm long from the intersection of the ribs to the three front ends, and 3mm deep) in the center of the 100mm×100mm convex part to form a protrusion (rib). Figure 11 The convex mold (for rib formation) is used as the upper mold and heated to 150°C.

[0155] The pre-prepared prepreg substrate is laminated to make Figure 11 The 0° direction is aligned with the 0° direction of the prepreg substrate laminate and is housed in the lower mold. After the upper mold is installed on the lower mold, the molding and curing of the matrix resin are carried out using a heated pressure molding machine under the conditions of 12MPa pressure, 150℃ heating temperature and 3 minutes of pressure to obtain ribbed fiber-reinforced plastic.

[0156] The obtained fiber-reinforced plastic has a Y-shaped rib in the center of a plate-shaped portion with a width of 100 mm × length of 100 mm × thickness of 0.7 mm. It was evaluated by the method described in the above <Evaluation of the filling property of fiber and resin into the protrusion>. As a result, [1] in the appearance observation of the protrusion, it was confirmed that carbon fiber filled to the front end of each rib. [2] in the cross-sectional observation of the protrusion, it was considered that there was a slight internal resin accumulation ("resin enrichment"), but it was also confirmed that the carbon fiber continuous with the plate-shaped portion filled into the interior of each rib, so it was rated as B.

[0157] Furthermore, the evaluation was conducted using the method described in the above-mentioned "Evaluation of Warpage of Molded Articles," and the result was A. + Evaluation (contact with the inspection table on a roughly flat surface, with the lift at the four corners being greater than 0.4mm and less than 0.7mm).

[0158] The inspection was conducted using the methods described in the "Appearance Inspection of the Design Surface of Molded Articles". As a result, regarding deformation, the reflected light from the fluorescent lamp was deformed only at a certain constant angle, which is rated as B. Regarding mesh distortion, the distortion was greater than 0.6 mm but less than 1.0 mm, which is rated as A.

[0159] [Example 2] according to Figure 7 The cutting pattern is designed to achieve a fiber length of 13mm, a cut width Ws=0.25mm, and a cut angle of... θ In a manner of ±14°, a roller cutter equipped with a tool on the barrel is pressed against a unidirectional prepreg blank manufactured by Toray Industries, Inc. #P384-S-7, thereby inserting a cut into the reinforcing fiber of the prepreg blank, resulting in a cut-inserted prepreg blank.

[0160] Insert the prepreg blank through the cut, and cut 8 pieces from a 100mm×100mm prepreg substrate. Lay them in a manner that makes them [+40 / -50 / +40 / -50]s to prepare a prepreg substrate laminate.

[0161] Next, prepare a 100mm x 100mm concave mold as the lower mold. Additionally, prepare an X-shaped groove (rib groove, 1.0mm wide, 40mm long from the intersection of the ribs to each of the four front ends, and 3mm deep) in the center of the 100mm x 100mm protrusion to form a rib. Figure 12 The convex mold of the rib is used as the upper mold and heated to 150°C.

[0162] Regarding the pre-prepared prepreg substrate laminate, Figure 12 The protrusion a is set to 0°. The above-mentioned substrate laminate is housed in the lower mold. After the upper mold is installed on the lower mold, the molding and heating curing of the matrix resin are carried out using a heated pressure molding machine under the conditions of pressure of 12MPa, heating temperature of 150℃ and pressure time of 3 minutes to obtain ribbed fiber reinforced plastic.

[0163] The obtained fiber-reinforced plastic has an X-shaped rib in the center of a plate-shaped portion with a width of 100 mm × length of 100 mm × thickness of 0.7 mm. Various evaluations were performed in the same manner as in Example 1, and as a result, [1] the appearance observation of the protrusion confirmed that carbon fibers filled to the front end of each rib. In addition, [2] the cross-sectional observation of the protrusion also confirmed that carbon fibers continuous with the plate-shaped portion filled into the interior of each rib, and the rib filling performance was rated as A.

[0164] The warping of the plate-like portion is A + Evaluation (contact with the inspection table on a roughly flat surface, with the lift at the four corners being greater than 0.4mm and less than 0.7mm).

[0165] For the visual inspection of the designed surfaces of the molded product, under fluorescent light observation, the reflected light from the fluorescent light only showed distortion at a certain constant angle, which is rated as B. Further, regarding the mesh distortion, it is between 0.3mm and 0.6mm, which is rated as A. + evaluate.

[0166] [Example 3] Prepare a prepreg substrate laminate in the same manner as in Example 2.

[0167] Next, prepare the same mold as in Example 2 and heat it to 150°C. Then, using the concave mold surface as the design surface, configure a fabric prepreg blank manufactured by Toray Industries, Inc. (#CO6343B carbon fiber with tensile strength of 3530 MPa, tensile modulus of elasticity of 230 GPa, and area weight of 198 g / m²). 2 As the substrate for the design surface, a resin-unimpregnated glass mat (90g / m²) is placed on it. 2 Furthermore, a pre-prepared prepreg substrate laminate is further disposed on its upper layer.

[0168] The molding conditions were set to be the same as in Example 2, and fiber-reinforced plastic with X-ribs was obtained by molding.

[0169] As in Example 1, various evaluations were performed, and as a result, [1] the appearance of the protrusions confirmed that carbon fibers filled to the front ends of each rib. In addition, [2] the cross-sectional observation of the protrusions also confirmed that carbon fibers, continuous with the plate-like portion, filled into the interior of each rib, and the rib filling performance was rated A.

[0170] The warping of the plate-like portion is A + Evaluation (contact with the inspection table on a roughly flat surface, with lift at the four corners greater than 0.4mm and less than 0.7mm).

[0171] For the visual inspection of the designed surfaces of molded products, under fluorescent light observation, products that show no deformation at any specified angle are rated A. Similarly, for fabrics, fiber widths of 90% or higher are also rated A. ++ Evaluation. It is believed that by inserting resin-unimpregnated glass mat between the two surface layers, the plastic flow caused by the pressure applied during compression molding can be mitigated by the glass mat, and the flow to the ribs is not affected by the layers inserted into the prepreg blank. The shape of the fabric prepreg blank constituting the design surface can be maintained. Therefore, a fiber-reinforced plastic with a better appearance than that of Example 2 can be obtained.

[0172] [Example 4] On top of the prepreg fabric blank in the design surface, resin-unimpregnated CF paper (48 g / m²) is inserted instead of glass mat. 2 Except for this, the process is the same as in Example 3 and is molded to obtain fiber-reinforced plastic.

[0173] As in Example 1, various evaluations were performed, and as a result, [1] the appearance of the protrusions confirmed that carbon fibers filled to the front ends of each rib. In addition, [2] the cross-sectional observation of the protrusions also confirmed that carbon fibers, continuous with the plate-like portion, filled into the interior of each rib, and the rib filling performance was rated A.

[0174] The warping of the plate-like portion is A +Evaluation (contact with the inspection table on a roughly flat surface, with lift at the four corners greater than 0.4mm and less than 0.7mm).

[0175] For the visual inspection of the designed surfaces of molded products, under fluorescent light observation, products that show no deformation at any specified angle are rated A. Similarly, for fabrics, fiber widths of 90% or higher are also rated A. ++ Evaluation. Similar to Example 3, it is believed that by inserting resin-unimpregnated CF paper between the two surface layers, the plastic flow caused by the pressure applied during compression molding can be mitigated by the CF paper. It is not affected by the layer of prepreg inserted into the ribs, and the shape of the fabric prepreg constituting the design surface can be maintained. Therefore, a fiber-reinforced plastic with a better appearance than that of Example 2 can be obtained.

[0176] [Example 5] On the upper layer of the fabric prepreg blank on the design surface, a fabric prepreg blank of the same type as the fabric prepreg blank on the design surface is inserted as a resin impregnated sheet instead of glass mat. Otherwise, it is set the same as in Example 3 (i.e., two layers of fabric prepreg blanks are inserted on the design surface side) and molded to obtain fiber reinforced plastic.

[0177] As in Example 1, various evaluations were performed, and as a result, [1] the appearance of the protrusions confirmed that carbon fibers filled to the front ends of each rib. In addition, [2] the cross-sectional observation of the protrusions also confirmed that carbon fibers, continuous with the plate-like portion, filled into the interior of each rib, and the rib filling performance was rated A.

[0178] The warping of the plate-like portion is A + Evaluation (contact on the approximate entire surface of the inspection table; lift at the four corners is greater than 0.4mm and less than 0.7mm).

[0179] For the visual inspection of the designed surfaces of the molded product, under fluorescent light, if deformation can only be visually observed at a specified constant angle, it is rated B. Regarding the fabric, if the fiber width is above 90%, it is rated A. ++ Evaluation. By overlapping two fabric prepreg blanks, the plastic flow caused by the pressure applied during compression molding can be mitigated by the inner fabric prepreg blank, and the layers of prepreg blanks that flow into the ribs are not affected by the cuts inserted into the prepreg blanks. The shape of the fabric prepreg blanks constituting the design surface can be maintained, and a fiber-reinforced plastic with a better appearance than that of Example 2 can be obtained.

[0180] [Example 6] The FAW of the prepreg blank with the notch used in Example 2 was set to 100 g / m. 2Six pieces of a 100mm × 100mm prepreg substrate are cut from the prepreg substrate through the aforementioned cut. These are then stacked in a manner that results in a thickness of [+40 / -50]³. Except for the aspects described above, the process is the same as in Example 2, resulting in a fiber-reinforced plastic with ribs and the same molded sheet thickness as in Example 2.

[0181] As in Example 1, various evaluations were performed, and as a result, [1] the appearance of the protrusions confirmed that carbon fibers filled to the front ends of each rib. In addition, [2] the cross-sectional observation of the protrusions also confirmed that carbon fibers, continuous with the plate-like portion, filled into the interior of each rib, and the rib filling performance was rated A.

[0182] The warping of the plate-like portion is A + Evaluation (contact on the approximate entire surface of the inspection table; lift at the four corners is greater than 0.4mm and less than 0.7mm).

[0183] For the visual inspection of the designed surface of the molded article, under fluorescent light, deformation that can be visually observed only at a specified constant angle is rated B. Further, regarding mesh distortion, a distortion exceeding 0.6 mm but less than 1.0 mm is rated A. The decrease in mesh distortion compared to Example 2 is attributed to the fact that by reducing the number of layers, the substrate on the designed surface side is also slightly affected by fiber flow towards the protrusions.

[0184] [Example 7] The FAW of the prepreg blank with the notch used in Example 2 was set to 120 g / m. 2 Five pieces of a 100mm × 100mm prepreg substrate are cut from the prepreg substrate through the aforementioned cut. These pieces are then stacked in a [45 / -50 / 45 / -50 / 45] configuration. Except for the aspects described above, the process is the same as in Example 2, resulting in a fiber-reinforced plastic with ribs and the same molded sheet thickness as in Example 2.

[0185] As in Example 1, various evaluations were performed, and as a result, [1] the appearance of the protrusions confirmed that carbon fibers filled to the front ends of each rib. In addition, [2] the cross-sectional observation of the protrusions also confirmed that carbon fibers, continuous with the plate-like portion, filled into the interior of each rib, and the rib filling performance was rated A.

[0186] The warping of the plate-like portion is A + Evaluation (contact on the approximate entire surface of the inspection table; lift at the four corners is greater than 0.4mm and less than 0.7mm).

[0187] For the visual inspection of the designed surface of the molded article, under fluorescent light, deformation can only be visually observed at a specified constant angle, which is rated as B. Further, mesh distortion exceeding 0.6 mm but less than 1.0 mm is rated as A. The decrease in mesh distortion compared to Example 2 is attributed to the fact that by reducing the number of layers, the substrate on the designed surface side is also slightly affected by fiber flow towards the protrusions.

[0188] [Example 8] The notch inserted into the prepreg blank used in Example 2 is set to FAW=100g / m². 2 Cut four pieces from a single 100mm x 100mm prepreg substrate. This will make it [0 / 90]. s The prepreg substrate laminate is prepared by stacking the prepreg substrates in a certain manner.

[0189] Next, prepare a 100mm x 100mm concave mold as the lower mold. Additionally, prepare a groove (rib groove, 1.5mm wide, ribs 40mm long, and 5mm deep) in the center of the 100mm x 100mm protrusion to form a "ハ" shape (ideally forming a rib). Figure 15 The convex mold (with ribs) is used as the upper mold and heated to 150°C. Then, the concave mold surface is used as the design surface, and the same prepreg fabric blank as in Example 3 is configured as the design surface substrate. On top of this, a prepreg fabric blank substrate laminate is prepared. Figure 15 The material is housed in the lower mold with the line shown at 0°. After the upper mold is installed on the lower mold, a heated pressure molding machine is used to perform molding and heat curing of the matrix resin under the conditions of pressure of 12MPa, heating temperature of 150℃ and pressure time of 3 minutes to obtain ribbed fiber-reinforced plastic.

[0190] The obtained fiber-reinforced plastic has a "ハ"-shaped rib in the center of a plate-shaped portion with a width of 100mm, a length of 100mm, and a thickness of 0.7mm.

[0191] As in Example 1, various evaluations were performed, and as a result, [1] the appearance of the protrusions confirmed that carbon fibers filled to the front ends of each rib. In addition, [2] the cross-sectional observation of the protrusions also confirmed that carbon fibers, continuous with the plate-like portion, filled into the interior of each rib, and the rib filling performance was rated A.

[0192] The warping of the plate-like portion is A + Evaluation (contact on the approximate entire surface of the inspection table; lift at the four corners is greater than 0.4mm and less than 0.7mm).

[0193] For the visual inspection of the design surface of the molded product, under fluorescent light, if the deformation can be visually observed only at a certain constant angle, it is rated as B. For the fiber width of the fabric, it is rated as A if it is above 75% and less than 80%.

[0194] [Example 9] The notch inserted into the prepreg blank used in Example 2 is set to FAW=100g / m². 2 Four prepreg blanks, each 100mm x 100mm in size, are cut from the prepreg blank through the aforementioned incision. This results in a [+40 / -50] ratio. s The prepreg substrate laminate is prepared by stacking the prepreg substrates in a certain manner.

[0195] Next, a 100mm × 100mm concave mold is used as the lower mold. Furthermore, a groove (rib groove, 1.5mm wide) is prepared in the center of the 100mm × 100mm protrusion to form a rib. Figure 13 The H-shape (ideally formed) consists of a length of 40mm from the intersection of protrusions a, b, and c to the two front ends of each of protrusions b and c, and a depth of 5mm. Figure 13 The convex mold (with ribs) is used as the upper mold and heated to 150°C. Furthermore, the concave mold surface is used as the design surface, and the same prepreg fabric blank as in Example 3 is used as the design surface substrate. On top of this, a pre-preg fabric blank laminate is placed... Figure 13 The protrusion a is housed in the lower mold at 0°. After the upper mold is installed on the lower mold, the molding and curing of the matrix resin are carried out using a heated pressure molding machine under the conditions of 12 MPa pressure, 150°C heating temperature and 3 minutes of pressure to obtain ribbed fiber-reinforced plastic.

[0196] The resulting fiber-reinforced plastic has an H-shaped rib in the center of a plate-shaped portion with a width of 100 mm, a length of 100 mm, and a thickness of 0.7 mm.

[0197] As in Example 1, various evaluations were performed, and as a result, [1] the appearance of the protrusions confirmed that carbon fibers filled to the front ends of each rib. In addition, [2] the cross-sectional observation of the protrusions also confirmed that carbon fibers, continuous with the plate-like portion, filled into the interior of each rib, and the rib filling performance was rated A.

[0198] The warping of the plate-like portion is A + Evaluation (contact on the approximate entire surface of the inspection table; lift at the four corners is greater than 0.4mm and less than 0.7mm).

[0199] For the visual inspection of the design surface of the molded product, under fluorescent light, if the deformation can be visually observed only at a certain constant angle, it is rated as B. For the fiber width of the fabric, it is rated as A if it is above 75% and less than 80%.

[0200] [Example 10] Six pieces of a 100mm × 100mm prepreg substrate were cut from the prepreg substrate using the slits used in Example 5. The prepreg substrates were then stacked in a manner that made them [+40 / -50]3 to prepare a prepreg substrate laminate. The fabric prepreg, which was not used as a resin-impregnated sheet, was otherwise set up in the same manner as in Example 5 to obtain a fiber-reinforced plastic.

[0201] As in Example 1, various evaluations were performed, and as a result, [1] the appearance of the protrusions confirmed that carbon fibers filled to the front ends of each rib. In addition, [2] the cross-sectional observation of the protrusions also confirmed that carbon fibers, continuous with the plate-like portion, filled into the interior of each rib, and the rib filling performance was rated A.

[0202] The warping of the plate-like portion is A + Evaluation (contact on the approximate entire surface of the inspection table; lift at the four corners is greater than 0.4mm and less than 0.7mm).

[0203] For the visual inspection of the design surface of the molded product, under fluorescent light, if the deformation can be visually observed only at a certain constant angle, it is rated as B. For the fiber width of the fabric, it is rated as A if it is above 75% and less than 80%.

[0204] [Example 11] Six pieces of a 100mm × 100mm prepreg substrate were cut from the prepreg substrate using the slits used in Example 2. The prepreg substrates were then stacked in a manner that made them [+40 / -50]3 to prepare a prepreg substrate laminate. The fabric prepreg, which was not used as a resin-impregnated sheet, was otherwise set up in the same manner as in Example 5 to obtain a fiber-reinforced plastic.

[0205] As in Example 1, various evaluations were performed, and as a result, [1] the appearance of the protrusions confirmed that carbon fibers filled to the front ends of each rib. In addition, [2] the cross-sectional observation of the protrusions also confirmed that carbon fibers, continuous with the plate-like portion, filled into the interior of each rib, and the rib filling performance was rated A.

[0206] The warping of the plate-like portion is A + Evaluation (contact on the approximate entire surface of the inspection table; lift at the four corners is greater than 0.4mm and less than 0.7mm).

[0207] For the visual inspection of the design surface of the molded product, under fluorescent light, if the deformation can be visually observed only at a certain constant angle, it is rated as B. For the fiber width of the fabric, it is rated as A if it is above 75% and less than 80%.

[0208] [Example 12] One layer of FAW=120g / m² is laminated under the prepreg fabric that forms the design surface. 2 The cut is inserted into the prepreg blank, and then 4 sheets of FAW=70g / m² are further stacked on the bottom layer. 2 The prepreg blank (i.e., replacing the prepreg substrate laminate in Example 10 with FAW=120g / m²) 2 Prepreg substrate and FAW=70g / m 2 The fiber-reinforced plastic was obtained, except as otherwise provided in Example 10.

[0209] Various evaluations were performed in the same manner as in Example 1. As a result, [1] in the appearance observation of the protrusion, it was confirmed that carbon fiber filled to the front end of each rib. [2] in the cross-sectional observation of the protrusion, it was also confirmed that carbon fiber, which is continuous with the plate-like portion, filled into the interior of each rib, and the rib filling performance was rated as A.

[0210] The warping of the plate-like portion is A + Evaluation (contact on the approximate entire surface of the inspection table; lift at the four corners is greater than 0.4mm and less than 0.7mm).

[0211] For the visual inspection of the designed surfaces of molded products, under fluorescent light observation, products that show no deformation at any angle are rated A. Similarly, for fabrics, a fiber width of 80% or more but less than 90% is also rated A. + evaluate.

[0212] [Example 13] The cut used in Example 7 was inserted into the prepreg blank and stacked in a manner of [45 / -50 / 45 / -50 / 45 / -50 / 45] for 7 layers. The stacking configuration was adjusted so that the thickness of the plate portion was 1.2 mm. Otherwise, it was set to be the same as in Example 7 to obtain fiber reinforced plastic.

[0213] Various evaluations were performed in the same manner as in Example 1. As a result, [1] in the appearance observation of the protrusion, it was confirmed that carbon fiber filled to the front end of each rib. [2] in the cross-sectional observation of the protrusion, it was also confirmed that carbon fiber, which is continuous with the plate-like portion, filled into the interior of each rib, and the rib filling performance was rated as A.

[0214] The warping of the plate-like portion is A + Evaluation (contact on the approximate entire surface of the inspection table; lift at the four corners is greater than 0.4mm and less than 0.7mm).

[0215] For the visual inspection of the designed surfaces of molded products, under fluorescent light observation, products that show no deformation at any angle are rated A. Similarly, for fabrics, a fiber width of 90% or more is also rated A. ++ evaluate.

[0216] [Example 14] The layers will be arranged in a configuration of [40 / -20]. S Four layers are stacked, and otherwise the same as in Example 8, to obtain fiber-reinforced plastic.

[0217] Various evaluations were performed in the same manner as in Example 1. As a result, [1] in the appearance observation of the protrusion, it was confirmed that carbon fiber filled to the front end of each rib. [2] in the cross-sectional observation of the protrusion, it was also confirmed that carbon fiber, which is continuous with the plate-like portion, filled into the interior of each rib, and the rib filling performance was rated as A.

[0218] The warping of the plate-like part is rated A (when in contact with the approximate entire surface of the inspection table, the lift at the four corners is greater than 0.7 mm and less than 1.0 mm).

[0219] For the visual inspection of the design surface of the molded product, under fluorescent light, if the deformation can be visually observed only at a certain constant angle, it is rated as B. For the fiber width of the fabric, it is rated as A if it is above 75% and less than 80%.

[0220] [Comparative Example 1] The unidirectional prepreg preform is arranged in a stacking direction as [0]. 12 The layers are stacked in a manner that ensures the fiber orientation is aligned with the direction of the fibers. Figure 11 The prepreg substrate laminate is housed in a mold in a parallel manner along the 0° direction. Otherwise, the fiber-reinforced plastic is molded using the same method and conditions as in Example 1 to obtain the fiber-reinforced plastic.

[0221] Various evaluations were performed in the same manner as in Example 1. The results showed that, [1] in the external observation of the protrusion, carbon fiber filled to the front end of the protrusion. However, [2] in the cross-sectional observation of the protrusion, only fibers parallel to the extending direction were found inside the portion of the rib extending along the 0° direction; no carbon fiber continuous with the plate-like portion was confirmed, resulting in an F rating. Therefore, it was considered that although carbon fiber was filled in the rib, the shear stress was weak. It should be noted that carbon fiber continuous with the plate-like portion filled the interior of the rib in the portion extending beyond the 0° direction.

[0222] The warping of the plate-like part is rated A (when the entire surface of the inspection table is in contact, the lift of the four corners is greater than 0.7 mm and less than 1 mm).

[0223] In addition, for the appearance inspection of the design surface of the molded product, observation under fluorescent light was carried out. The results confirmed that there was deformation of the reflected light from the fluorescent light at any angle, which was rated as F. Furthermore, the mesh distortion also exceeded 1.0 mm, which was also rated as F.

[0224] [Comparative Example 2] The unidirectional prepreg preforms are arranged in a stacking direction to form

[90] 12 The layers are stacked in a manner that ensures the fiber orientation is aligned with the direction of the fibers. Figure 11 The prepreg substrate laminate is housed in a mold in a parallel manner along the 0° direction. Otherwise, the fiber-reinforced plastic is molded using the same method and conditions as in Example 1 to obtain the fiber-reinforced plastic.

[0225] The evaluation was conducted using the method described in the above-mentioned <Evaluation of the Filling Performance of Fibers and Resin into the Protrusions>. As a result, [1] in the visual observation of the protrusions, the carbon fibers were not filled to the front end of the portion extending along the 0° direction of the rib, resulting in "unfilled" and "resin enrichment" in the upper part, making it impossible to obtain the target shape. For the portion extending beyond the 0° direction of the rib, the carbon fibers were filled to the front end. Moreover, [2] the cross-sectional observation of the protrusions showed that although the carbon fibers inside the portion extending along the 0° direction of the rib were continuous with the carbon fibers of the plate-like portion, the upper part was only resin, indicating that only the matrix resin had flowed. Furthermore, it was confirmed that the carbon fibers continuous with the plate-like portion were filled into the interior of the rib in the portion extending beyond the 0° direction of the rib. Since the target shape could not be obtained, the above-mentioned <Evaluation of Warpage of Molded Article> and <Visual Inspection of the Design Surface of Molded Article> were not performed.

[0226] [Comparative Example 3] The unidirectional prepreg blanks were stacked in a stacking direction of [0 / 90]6. Otherwise, the fiber-reinforced plastic was molded using the same method and conditions as in Example 1 to obtain the fiber-reinforced plastic.

[0227] The evaluation was conducted using the method described in the above-mentioned <Evaluation of the Filling Properties of Fibers and Resin into the Protrusions>. As a result, regarding the portion of the rib extending in the 0° direction, [1] based on the visual observation of the protrusion, it was known that carbon fibers filled to the front end. However, [2] the cross-sectional observation of the protrusion showed that although carbon fibers were observed at the front end of the rib, these carbon fibers were discontinuous with the carbon fibers present inside the plate-like portion, resulting in "resin enrichment". This was attributed to the fact that only the surface carbon fibers in the 0° direction flowed, and the carbon fibers below the second layer could not flow to the upper part of the rib. On the other hand, it was confirmed that in the portion of the rib extending outside the 0° direction, carbon fibers continuous with the plate-like portion filled into the interior of the rib. Since the target shape could not be obtained, the above-mentioned <Evaluation of Warpage of Molded Article> and <Visual Inspection of the Design Surface of Molded Article> were not performed.

[0228] [Table 1] [Table 2] [Table 3] [Table 4] Industrial availability The fiber-reinforced plastic of the present invention is preferably used in components requiring strength, rigidity, and lightweight, as well as components with complex shapes that require shape conformity with other components. In particular, it can be used in the aforementioned high-strength components such as bicycle cranks and frames, golf club shafts and heads, structural components such as automobile doors, seats, components, modules, or frames, outer panels and interior materials, and mechanical parts such as robotic arms. Furthermore, it is also preferably used in structural components and outer panels of medical devices and information communication equipment.

[0229] Explanation of reference numerals in the attached figures 1: Width of the longitudinal section of the protrusion (width of the protrusion) 2: Width of the cross-section of the protrusion (length of the protrusion) 3: Height of the protrusion 4: Insert the cut into the prepreg blank 5: Fiber orientation direction 6: Fiber vertical direction 7: Discontinuous incisions 8: Continuous incisions 9: Intermittent oblique cuts (at a positive angle relative to the fiber direction) 10: Discontinuous oblique cuts (at a negative angle relative to the fiber direction) 11: Columns of discontinuous incisions 20: Length direction of the protrusion 21: Width direction of the protrusion 22: Cross-section of the protrusion 23: Longitudinal section of the protrusion 100: plate-shaped part 200: Protrusion 203: Direction of the protrusion's extension 204: Direction of the protrusion's extension 205: Direction of the protrusion's extension 300: Reinforcing Fiber 400: The surface layer opposite to the side with the protrusion. 401: Reinforcing Fiber 402: Mesh distortion 500: Depression 600: Unfilled area

Claims

1. A fiber-reinforced plastic, characterized in that it is formed of a shape having a plate-like portion and at least one protrusion arising from at least one side of the plate-like portion, wherein... The plate-like portion has at least one layer of multiple reinforcing fibers arranged unidirectionally in the matrix resin, i.e., a unidirectional layer. In the fiber-reinforced plastic, the protrusions extend in at least two different directions, and at least two of the directions in which the protrusions extend are neither parallel nor perpendicular to each other. Furthermore, all the directions in which the protrusions extend are neither parallel nor perpendicular to the fiber orientation direction in any unidirectional layer of the plate-like portion.

2. The fiber-reinforced plastic as described in claim 1, wherein, It has at least one unidirectional layer whose fiber orientation is neither parallel nor perpendicular to all directions in which the protrusion extends.

3. The fiber-reinforced plastic as described in claim 1 or 2, wherein, The plate-shaped portion has at least two unidirectional layers, the fiber orientations of which are not parallel to each other.

4. The fiber-reinforced plastic as described in claim 1 or 2, wherein, The plate-shaped portion has at least two unidirectional layers, the fiber orientations of which are perpendicular to each other.

5. The fiber-reinforced plastic as described in claim 1 or 2, wherein, The angle formed by all directions in which the protrusion extends and the fiber orientation direction in any unidirectional layer of the plate-like portion is 15° to 80° or 100° to 165°.

6. The fiber-reinforced plastic as described in claim 1 or 2, wherein, The fiber unit area weight of at least one layer of the unidirectional layer inside the plate-shaped portion is 70 g / m². 2 Above, 200g / m 2 the following.

7. The fiber-reinforced plastic as described in claim 1 or 2, wherein, At least one of the unidirectional layers located inside the plate-like portion comprises reinforcing fibers with a fiber length of 10 to 300 mm.

8. The fiber-reinforced plastic as described in claim 1 or 2, wherein, The plate-shaped portion contains two or more unidirectional layers with different fiber unit area weights.

9. The fiber-reinforced plastic of claim 8, wherein, The outermost layer on the protrusion side of the plate-shaped portion is a unidirectional layer, and the fiber unit area weight of this outermost unidirectional layer is less than the fiber unit area weight of at least one unidirectional layer in the plate-shaped portion other than the outermost layer on the protrusion side.

10. The fiber-reinforced plastic as claimed in claim 1 or 2, wherein, The plate-like portion has multiple layers formed of reinforcing fibers and matrix resin, and the protrusion is only on one side of the plate-like portion. At least one layer of the layers other than the outermost layer of the side with the protrusion is a layer in which multiple reinforcing fibers are oriented in at least two directions in the matrix resin, i.e., a non-unidirectional layer.

11. The fiber-reinforced plastic as claimed in claim 1 or 2, wherein, The plate-shaped portion has multiple layers formed of reinforcing fibers and matrix resin, and the protrusion is only on one side of the plate-shaped portion. The outermost layer of the reinforcing fibers forming the opposite side of the one-sided surface is made of fabric.

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