Eyeglass frames and fiber-reinforced molded bodies

Abstract

To provide a three-dimensional shaped fiber reinforced molded body having a bent part which is bent at a sharp angle, without rupture of a carbon fiber.SOLUTION: There is provided a fiber reinforced molded body 1 comprising: a front layer 3 including a carbon fiber fabric; a fiber assembly layer 5 which is at inside relative to the front layer 3, and includes a carbon fiber which is oriented at an angle greater than 0 degree and less than 90 degrees, to an orientation direction of one carbon fiber forming the carbon fiber fabric; and a resin foam layer 7. The fiber reinforced molded body 1 is integrated by a cured object of a thremosetting resin, and has a bent part 17 bent at a sharp angle, the fiber reinforced molded body being formed into a three-dimensional shape. At the bent part 17, the fiber assembly layer 5 is laminated adjacent to the front layer 3.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This disclosure relates to fiber-reinforced molded articles, prepregs for molding three-dimensional objects, and methods for manufacturing fiber-reinforced molded articles. [Background technology]

[0002] Patent Document 1 discloses a fiber-reinforced molded article having a structure in which a foam is covered with carbon fibers. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2019-116254 [Overview of the project] [Problems that the invention aims to solve]

[0004] When a fiber-reinforced molded body is a three-dimensional object with a gentle curved surface, fiber breakage is less likely to occur during molding using a pressure mold. However, if the fiber-reinforced molded body is a three-dimensional object with a highly irregular shape, there is a risk of fiber breakage during molding using a pressure mold. Therefore, there were limitations on the shape of the three-dimensional object. The present disclosure aims to provide a three-dimensional object with a highly irregular shape, such as a fiber-reinforced molded body with sharply bent sections, without causing fiber breakage, and can be realized in the following forms. [Means for solving the problem]

[0005] A surface layer containing carbon fiber fabric, A fiber aggregate layer containing carbon fibers arranged inside the surface layer and oriented at an angle greater than 0 degrees and less than 90 degrees with respect to the orientation direction of one of the carbon fibers constituting the carbon fiber fabric, A fiber-reinforced molded article comprising a resin foam layer, It is integrated by a cured thermosetting resin, It has a three-dimensional shape with sharply bent sections, In the bent portion, the fiber aggregate layer is laminated adjacent to the surface layer in a fiber-reinforced molded body. [Effects of the Invention]

[0006] According to this disclosure, a three-dimensional fiber-reinforced molded body having sharply bent portions without carbon fiber breakage is provided. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a schematic cross-sectional view showing an example of a laminated structure of a fiber-reinforced molded body. [Figure 2] Figure 2 is a schematic diagram illustrating the manufacturing method of prepregs for three-dimensional molding and fiber-reinforced molded articles. [Figure 3] Figure 3 is a perspective view showing an eyeglass frame. [Figure 4] Figure 4 is a cross-sectional view of AA in Figure 3. [Figure 5] Figure 5 is an explanatory diagram illustrating the presumed function of a conventional fiber-reinforced molded body. [Figure 6] Figure 6 is an explanatory diagram illustrating the presumed function of a conventional fiber-reinforced molded body. [Figure 7] Figure 7 is an explanatory diagram illustrating the presumed function of the fiber-reinforced molded article of this disclosure. [Figure 8] Figure 8 is an explanatory diagram illustrating the presumed function of the fiber-reinforced molded article of this disclosure. [Modes for carrying out the invention]

[0008] Herein lies a preferred example of this disclosure. • A fiber-reinforced molded body having multiple fiber aggregate layers. The resin foam layer is a fiber-reinforced molded body containing melamine resin foam. The bent portion has a first surface and a second surface where the surface layers are joined at an acute angle, The second surface is a surface aligned with the pressing direction, The fiber-reinforced molded body, wherein the maximum width of the second surface is 1 mm or more and 5 mm or less. · A prepreg for a surface layer including a carbon fiber fabric and impregnated with a thermosetting resin, A prepreg for a fiber aggregate layer disposed inside the surface layer, including carbon fibers oriented at an angle greater than 0 degrees and less than 90 degrees with respect to the orientation direction of one carbon fiber constituting the carbon fiber fabric, and impregnated with the thermosetting resin, A prepreg for a foam layer including a resin foam and impregnated with the thermosetting resin, A prepreg for forming a three-dimensional object having a bent portion bent at an acute angle. · A prepreg for a surface layer including a carbon fiber fabric and impregnated with a thermosetting resin, A prepreg for a fiber aggregate layer disposed inside the surface layer, including carbon fibers oriented at an angle greater than 0 degrees and less than 90 degrees with respect to the orientation direction of one carbon fiber constituting the carbon fiber fabric, and impregnated with the thermosetting resin, A method for manufacturing a fiber-reinforced molded body using a prepreg for forming a three-dimensional object, comprising a prepreg for a surface layer including a carbon fiber fabric and impregnated with a thermosetting resin, a prepreg for a fiber aggregate layer disposed inside the surface layer, including carbon fibers oriented at an angle greater than 0 degrees and less than 90 degrees with respect to the orientation direction of one carbon fiber constituting the carbon fiber fabric, and impregnated with the thermosetting resin, and a prepreg for a foam layer including a resin foam and impregnated with the thermosetting resin, wherein the prepreg for forming a three-dimensional object is disposed between a lower pressure mold and an upper pressure mold, at least one of which has at least one of a concave portion and a convex portion formed on a mold surface thereof, the prepreg for forming a three-dimensional object is pressed and heated by the lower pressure mold and the upper pressure mold, and the thermosetting resin is cured to form a bent portion bent at an acute angle by the mold surface on the surface layer. The three-dimensional object forming prepreg is disposed between the lower pressure mold and the upper pressure mold, at least one of which has at least one of a concave portion and a convex portion formed on a mold surface thereof, The three-dimensional object forming prepreg is pressed and heated by the lower pressure mold and the upper pressure mold, The thermosetting resin is cured to form a bent portion bent at an acute angle by the mold surface on the surface layer.

[0009] Hereinafter, the present disclosure will be described in detail. In this specification, for a description using "-" for a numerical range, unless otherwise specified, it is assumed to include the lower limit value and the upper limit value. For example, in the description of "10-20", both the lower limit value "10" and the upper limit value "20" are included. That is, "10-20" has the same meaning as "10 or more and < 20 or less".

[0010] 1. Fiber-reinforced molded body 1 As illustrated in Figure 1, the fiber-reinforced molded body 1 comprises (i) a surface layer 3 containing a carbon fiber fabric, (ii) a fiber aggregate layer 5 containing carbon fibers arranged inside the surface layer 3 and oriented at an angle greater than 0 degrees and less than 90 degrees with respect to the orientation direction of one of the carbon fibers constituting the carbon fiber fabric, and (iii) a resin foam layer 7. The fiber-reinforced molded body 1 is integrated by a cured thermosetting resin. As illustrated in Figure 4, the fiber-reinforced molded body 1 has a three-dimensional shape with a sharply bent portion 17. In the bent portion 17, the surface layer 3 and the fiber aggregate layer 5 are laminated adjacent to each other as layers containing carbon fibers.

[0011] (1) Surface layer 3 The surface layer 3 can be formed by molding a carbon fiber prepreg 3A for the surface layer, which includes a carbon fiber fabric, as illustrated in Figure 2. The carbon fiber prepreg 3A for the surface layer consists of a carbon fiber fabric 3B impregnated with a thermosetting resin. The carbon fiber fabric 3B is lightweight and has excellent rigidity. Examples of carbon fiber fabrics 3B include plain weave, twill weave, satin weave, and triaxial weave composed of warp and weft threads. From the viewpoint of enhancing the design of the surface layer 3, for example, a plain weave carbon fiber fabric (woven fabric) of carbon fibers oriented at 0 / 90 degrees is preferably used as the carbon fiber fabric 3B. The thickness of the carbon fiber fabric 3B is not particularly limited. From the viewpoint of ensuring the strength of the surface of the fiber-reinforced molded body 1 while improving the appearance, the thickness of the carbon fiber fabric 3B is preferably, for example, 0.05 mm to 0.15 mm, and more preferably 0.08 mm to 0.12 mm. Carbon fiber fabric 3B has a fiber weight of 50 g / m, which is advantageous from the viewpoint of thermosetting resin impregnation and rigidity. 2 -110g / m 2 Those that are preferable.

[0012] The thermosetting resin impregnated into the carbon fiber fabric 3B is not particularly limited. From the viewpoint of increasing the rigidity of the fiber-reinforced molded body 1, the thermosetting resin is preferably selected from the group consisting of epoxy resins, phenolic resins, and mixtures of epoxy resins and phenolic resins. From the viewpoint of ensuring the lightness and rigidity of the fiber-reinforced molded body 1, the ratio of carbon fiber fabric 3B to the thermosetting resin impregnated therein is preferably as follows: When the total of carbon fiber fabric 3B and the thermosetting resin impregnated therein is 100% by mass, it is preferable that the amount of thermosetting resin impregnated therein be 50%-80% by mass, and more preferably 55%-70% by mass.

[0013] Furthermore, the carbon fiber prepreg 3A for the surface layer may have a porous sheet 4 on at least one side. A urethane resin foam is preferably used as the porous sheet 4. A foam with an open-cell structure is even more preferably used as the porous sheet 4. The number of cells in the urethane resin foam used as the porous sheet 4 is not particularly limited. From the viewpoint of ensuring sufficient impregnation of the thermosetting resin, the number of cells is preferably 8 cells / 25mm to 100 cells / 25mm (JIS K6400-1), and more preferably 10 cells / 25mm to 90 cells / 25mm (JIS K6400-1). The thickness of the porous sheet 4 is not particularly limited. When using urethane resin foam, a thickness of 0.4 mm to 3 mm is preferred in the uncompressed state (before manufacturing the fiber-reinforced molded body 1) from the viewpoint of appearance, and 0.6 mm to 2 mm is more preferred.

[0014] (2) Fiber aggregate layer 5 The fiber aggregate layer 5 contains carbon fibers oriented at an angle greater than 0 degrees and less than 90 degrees with respect to the orientation direction of one of the carbon fibers constituting the carbon fiber fabric 3B of the surface layer 3. The fiber aggregate layer 5 can be formed by molding an inner layer carbon fiber prepreg 5A (corresponding to a prepreg for the fiber aggregate layer) containing carbon fibers, as illustrated in Figure 2. The inner layer carbon fiber prepreg 5A consists of a carbon fiber aggregate 5B impregnated with a thermosetting resin. The aggregate 5B may be a woven fabric such as a plain weave, twill weave, satin weave, or triaxial weave composed of warp and weft threads, or an aggregate 5B in which the carbon fibers are oriented in one direction. An inner layer carbon fiber prepreg 5A using an aggregate 5B in which the carbon fibers are oriented in one direction is a UD prepreg. As the aggregate 5B, for the following reasons, an aggregate 5B containing carbon fibers oriented at an angle greater than 0 degrees and less than 90 degrees, preferably 30 degrees or more and 60 degrees or less, with respect to the orientation direction of one carbon fiber constituting the carbon fiber woven fabric 3B of the surface layer 3 is used. In particular, a plain weave carbon fiber fabric (woven material) with carbon fibers oriented at ±45 degrees is preferably used. When a carbon fiber fabric with such orientation is used, the pressure received from the mold is effectively deflected, and the fiber weave is appropriately twisted, improving the conformability to the mold, improving shape transfer to the mold, and resulting in a molded product with a high appearance that matches the design. From the viewpoint of impregnation of thermosetting resin and rigidity, aggregate 5B has a fiber weight of 50 g / m 2 -600g / m 2 Those that are preferable. The number of fiber aggregate layers 5 is not particularly limited. From the viewpoint of suppressing carbon fiber breakage and obtaining a fiber-reinforced molded body 1 with a high appearance as designed, the number of layers is preferably 2 to 5.

[0015] The thermosetting resin impregnated into the aggregate 5B is not particularly limited. From the viewpoint of increasing the rigidity of the fiber-reinforced molded body 1, the thermosetting resin is preferably selected from the group consisting of epoxy resin, phenolic resin, and mixtures of epoxy resin and phenolic resin. From the viewpoint of ensuring the lightness and rigidity of the fiber-reinforced molded body 1, the ratio of aggregate 5B to the thermosetting resin impregnated therein is preferably as follows: When the total of aggregate 5B and the thermosetting resin impregnated therein is 100% by mass, it is preferable that the amount of thermosetting resin impregnated therein be 50%-80% by mass, and more preferably 55%-70% by mass.

[0016] Furthermore, the inner layer carbon fiber prepreg 5A may have a porous sheet 4 on at least one side. A urethane resin foam is preferably used as the porous sheet 4. A foam with an open-cell structure is even more preferably used as the porous sheet 4. The number of cells in the urethane resin foam used as the porous sheet 4 is not particularly limited. From the viewpoint of ensuring sufficient impregnation of the thermosetting resin, the number of cells is preferably 8 cells / 25mm to 100 cells / 25mm (JIS K6400-1), and more preferably 10 cells / 25mm to 90 cells / 25mm (JIS K6400-1). The thickness of the porous sheet 4 is not particularly limited. When using urethane resin foam, a thickness of 0.4 mm to 3 mm is preferred in the uncompressed state (before manufacturing the fiber-reinforced molded body 1) from the viewpoint of appearance, and 0.6 mm to 2 mm is more preferred.

[0017] (3) Resin foam layer 7 The resin foam layer 7 can be formed by molding a foam prepreg 7A (a porous prepreg corresponding to a prepreg for a foam layer) as illustrated in Figure 2. It is preferable that the resin foam layer 7 be positioned inside the fiber aggregate layer 5. The foam prepreg 7A is a foam (porous material) impregnated with a thermosetting resin. The foam is not particularly limited. From the viewpoint of appearance, a foam having an open-cell structure is suitable. Examples of foams that can be used include melamine resin foam, urethane resin foam, polyolefin foam, and polyamide foam. When the foam has an open-cell structure, not only is it easier for the thermosetting resin to impregnate it, but it also becomes possible to mold it with a high compressibility. By selecting the above materials as the foam, compression molding becomes possible. In particular, melamine resin foam is preferred as the foam from the viewpoint of thermosetting resin impregnation, thermoformability, and the appearance of the fiber-reinforced molded article after molding. When flame retardancy is required for the fiber-reinforced molded article 1, melamine resin foam is suitable because it has good flame retardancy. The original thickness of the foam before compression is set as appropriate, and examples of this thickness include 3 mm to 25 mm. Furthermore, from the viewpoint of ease of compression, impregnation, lightness, and rigidity, the density of the foam before compression should be 5 kg / m³. 3 -100kg / m 3 Those that are preferable.

[0018] The thermosetting resin impregnated into the foam prepreg 7A is not particularly limited. From the viewpoint of increasing the rigidity of the fiber-reinforced molded body 1, the thermosetting resin is preferably selected from the group consisting of epoxy resins, phenolic resins, and mixtures of epoxy resins and phenolic resins.

[0019] (4) Other layers (4.1) Surface layer on the back side 11 The fiber-reinforced molded body 1 may have a back surface layer 11 containing a carbon fiber fabric on its back side. The back surface layer 11 can be formed by molding the above-mentioned carbon fiber prepreg 3A for the surface layer, as illustrated in Figure 2. The back surface layer 11 may also be formed by stacking multiple layers of carbon fiber prepreg 3A for the surface layer. For example, the back surface layer 11 may comprise a first back surface layer 11A, a second back surface layer 11B, and a third back surface layer 11C, as shown in Figure 1.

[0020] (4.2) Other carbon fiber layers as intermediate layer 13 The fiber-reinforced molded body 1 may include other carbon fiber layers as an intermediate layer 13. Other carbon fiber layers can be formed by molding an intermediate layer carbon fiber prepreg 13A containing a carbon fiber fabric 13B, as illustrated in Figure 2. This intermediate layer carbon fiber prepreg 13A is constructed by impregnating a carbon fiber fabric 13B with a thermosetting resin. The carbon fiber fabric 13B is excellent in lightness and rigidity. Examples of carbon fiber fabrics 13B include plain weave, twill weave, satin weave, and triaxial weave composed of warp and weft threads. From the viewpoint of increasing the strength of the fiber-reinforced molded body 1, for example, a twill weave carbon fiber fabric (woven fabric) of carbon fibers oriented at 0 / 90 degrees is preferably used as the carbon fiber fabric 13B. From the viewpoint of increasing the strength of the fiber-reinforced molded body 1, the thickness of the carbon fiber fabric 13B is preferably 0.15 mm to 0.35 mm, and more preferably 0.20 mm to 0.30 mm. From the viewpoint of thermosetting resin impregnation and rigidity, the fiber weight of the carbon fiber fabric 13B is 50 g / m 2 -600g / m 2 Those that are preferable.

[0021] The thermosetting resin impregnated into the carbon fiber fabric 13B is not particularly limited. From the viewpoint of increasing the rigidity of the fiber-reinforced molded body 1, the thermosetting resin is preferably selected from the group consisting of epoxy resins, phenolic resins, and mixtures of epoxy resins and phenolic resins. From the viewpoint of ensuring the lightness and rigidity of the fiber-reinforced molded body 1, the ratio of carbon fiber fabric 13B to the thermosetting resin impregnated therein is preferably as follows: When the total of carbon fiber fabric 13B and the thermosetting resin impregnated therein is 100% by mass, it is preferable that the amount of thermosetting resin impregnated therein be 50%-80% by mass, and more preferably 55%-70% by mass.

[0022] Furthermore, the carbon fiber prepreg 13A for the intermediate layer may have a porous sheet 4 on at least one side. A urethane resin foam is preferably used as the porous sheet 4. A foam with an open-cell structure is even more preferably used as the porous sheet 4. The number of cells in the urethane resin foam used as the porous sheet 4 is not particularly limited. From the viewpoint of ensuring sufficient impregnation of the thermosetting resin, the number of cells is preferably 8 cells / 25mm to 100 cells / 25mm (JIS K6400-1), and more preferably 10 cells / 25mm to 90 cells / 25mm (JIS K6400-1). The thickness of the porous sheet 4 is not particularly limited. When using urethane resin foam, a thickness of 0.4 mm to 3 mm is preferred in the uncompressed state (before manufacturing the fiber-reinforced molded body 1) from the viewpoint of appearance, and 0.6 mm to 2 mm is more preferred.

[0023] (5) Preferred laminated structure of fiber-reinforced molded body 1 A preferred laminated structure of the fiber-reinforced molded body 1 is shown in Figure 1, in which the layers are arranged in the following order from the surface side. The eighth layer, the back surface layer 11, is specifically composed of three layers: the first back surface layer 11A, the second back surface layer 11B, and the third back surface layer 11C. 1st layer Surface layer 3 Second layer: Fiber aggregate layer 5 Third layer: Fiber aggregate layer 5 4th layer: Resin foam layer 7 5th layer, intermediate layer 13 6th layer: Resin foam layer 7 7th layer, intermediate layer 13 8th layer, back side surface layer 11

[0024] (6) Three-dimensional shape of fiber-reinforced molded body 1 The fiber-reinforced molded body 1 of this disclosure has a three-dimensional shape having a sharply bent portion 17. Figure 3 shows a front 19 (front frame) of an eyeglass frame as an example of the fiber-reinforced molded body 1. The front 19 is a single molded piece. The front 19 is provided with a pair of left and right rims 21, 21. A connecting portion 23 is positioned between the rims 21, 21. As shown in Figure 3, from the viewpoint of improving the design, it is preferable that the front 19 be configured such that a grid pattern can be observed from the outside, at least at the connecting portion 23. The rims 21, 21 may also be configured such that a grid pattern can be observed from the outside. As for the grid pattern, a checkerboard pattern is preferred from the viewpoint of design. For example, it is preferable that the carbon fiber fabric 3B intersecting in the vertical and horizontal directions of the front 19 is observed from the outside to appear as a checkerboard pattern. In the eyeglass frame, for example, curved armor (not shown) is attached to the outside of the rims 21, 21 of the front 19, and temples (not shown) are connected to both armors. The rim 21 is a frame that surrounds the lens. Figures 3 and 4 show an example in which the rim 21 has a bent portion 17 in which the rim surface (frame surface) is sharply bent at an acute angle in a cross section perpendicular to the direction of the frame surrounding the lens. The position of the sharply bent portion 17 is not particularly limited.

[0025] Figure 4 shows a cross-section of the bent portion 17 in Figure 3. In this cross-section, only the surface layer 3, fiber aggregate layer 5, and resin foam layer 7 in Figure 1 are schematically shown, and the layers below (inside) the resin foam layer 7 in Figure 1 are omitted. In cross-sectional view, the bent portion 17 has a first surface 25 and a second surface 27, where the surface layer 3 is joined at an acute angle. A corner 29 is located at the boundary between the first surface 25 and the second surface 27. The corner 29 may be rounded by about 0.1 mm to 1 mm, or even 0.1 mm to 2 mm, in cross-section. The second surface 27 is a surface along the press direction 31. The second surface 27 forms a part of the inner surface area of ​​the rim 21. The second surface 27 is formed by pressing the uppermost carbon fiber fabric 3B shown in Figure 2 with an upper press mold 43. Even if the angle between the first surface 25 and the second surface 27 at the bent portion 17 (bending angle) is 30 degrees or more and less than 90 degrees, the present invention makes it possible to form a three-dimensional fiber-reinforced molded body without carbon fiber breakage, even if the angle is 35 degrees or more and less than 90 degrees, and even if the angle is 40 degrees or more and less than 80 degrees. Furthermore, even when the angle (bending angle) between the first surface 25 and the second surface 27 is 30 degrees or more and less than 110 degrees, the technology of this disclosure can form a three-dimensional fiber-reinforced molded body without carbon fiber breakage, and can also be formed without carbon fiber breakage even when the angle is 35 degrees or more and less than 100 degrees, and can also be formed even when the angle is 40 degrees or more and less than 90 degrees. When the maximum width W of the second surface 27 is 2 mm or more, and more specifically 6 mm or more, and especially 11 mm or more (with an upper limit of, for example, 16 mm or less), a three-dimensional object with a highly irregular shape is formed. Even with such a three-dimensional object, carbon fiber breakage is suppressed in the fiber-reinforced molded body 1 of this disclosure. In order to form the sharply bent portion 17, there are parts of the mold that are sharply angled. In other words, when molding a highly irregular shape, the shape of that part of the molding die changes significantly locally. To put it another way, there are parts of the molding die where the step in the press direction 31 is deep (for example, parts of 2 mm or more, and more specifically 6 mm or more, and especially parts of 11 mm or more, with an upper limit of, for example, 16 mm or less). Therefore, in conventional molded bodies, local stress on the molding material (prepreg) being used increases, and there was a risk of carbon fiber breakage. Thus, conventionally, in order to obtain a good product, it was necessary to make a smooth shape, which compromised the design. In the fiber-reinforced molded body 1 of this disclosure, even if the three-dimensional shape has a sharply bent portion 17, the breakage of the carbon fibers is suppressed, thus increasing the degree of design freedom and providing superior aesthetics.

[0026] (7) Action of the fiber-reinforced molded body 1 Figure 5 schematically shows a conventional example in which three plain-weave carbon fiber prepregs 3A with 0 / 90 degree orientation for the surface layer are laminated with foam prepreg 7A. In this case, the carbon fibers F in the first, second, and third layers of the surface carbon fiber prepreg 3A are oriented in the same direction. Therefore, it is presumed that, in response to stress in the elongation direction of the carbon fibers F in the first layer (force in the direction indicated by the arrow), the second and third layers will also change from the state shown in the left diagram of Figure 6 to the state shown in the right diagram, suffering the same damage as the first layer, and the appearance of the fiber-reinforced molded body 1 will be impaired. Note that Figure 6 is a conceptual diagram of the second and third layers, as previously described. For example, let's assume that the bending occurs at the dashed line in Figure 5, and that the bending occurs at the dashed line in the center of the top and bottom of Figure 6 in the second and third layers. In this case, the carbon fibers F1 in the second and third layers, which are oriented to extend in the vertical direction in Figure 6, are perpendicular to the dashed line, and will be bent at approximately the same angle as the bending angle of the bent section 17. In other words, in each of the first, second, and third layers of the bent section, there will be carbon fibers that can be bent to approximately the same angle as the bending angle of the bent section 17. Figure 7 schematically shows a case where, from top to bottom, a plain weave carbon fiber prepreg 3A for the surface layer with a 0 / 90 degree orientation, a plain weave carbon fiber prepreg 5A for the inner layer with a ±45 degree orientation, a plain weave carbon fiber prepreg 5A for the inner layer with a ±45 degree orientation, and a foam prepreg 7A are laminated. In this case, the carbon fiber prepreg 5A for the second and third inner layers has its carbon fibers F oriented in a different direction compared to the carbon fiber prepreg 3A for the first outer layer. Therefore, with respect to the stress on the carbon fibers F of the first layer in the elongation direction, the second and third layers change from the state shown in the left diagram of Figure 8 to the state shown in the right diagram, and it is presumed that the pressure received from the mold is effectively deflected, and the fiber weave is appropriately twisted, thereby improving the ability to follow the mold. Note that Figure 8 is a conceptual diagram of the second and third layers, as previously described. For example, let's assume that the bend occurs at the dashed line in Figure 7, and that in the second and third layers, the bend occurs at the dashed line in the center of the top and bottom of Figure 8. In this case, in the second and third layers, the carbon fiber F is bent at a 45-degree angle to the dashed line, so the angle formed by the bending of the carbon fiber itself in the second and third layers will be a gentler and larger angle than the bending angle of the bent section 17. That is, in the first layer, some of the carbon fiber F are bent at almost the same angle as the bending angle of the bent section 17, but in the second and third layers, the carbon fiber F is bent at a gentler angle than the bending angle of the bent section 17. As a result, it is believed that the shape transfer to the mold will improve, and a high-quality fiber-reinforced molded body 1 with a design-accurate appearance can be obtained.

[0027] Furthermore, in the fiber-reinforced molded body 1 of this disclosure, the resin foam layer 7 is provided on the underside (inside in the direction of bending) of the carbon fiber layer. Therefore, by controlling the degree of deformation during bending molding, the thickness of each part can be adjusted, and fiber breakage can be mitigated. Thus, the optimal thickness can be applied to the optimal location, resulting in a highly aesthetic three-dimensional shape.

[0028] (8) Others The fiber-reinforced molded article 1 of this disclosure may be colored. If coloring is performed, the thermosetting resin used for impregnation may be colored. The resin foam layer 7 may also be colored.

[0029] 2. Prepregs for molding three-dimensional objects The prepreg for molding three-dimensional objects according to this disclosure comprises a surface layer prepreg, a fiber aggregate layer prepreg, and a foam layer prepreg. The surface prepreg contains carbon fiber fabric and is impregnated with thermosetting resin. The surface prepreg corresponds to the "Surface carbon fiber prepreg 3A" described in section "1. Fiber-reinforced molded body 1 (1) Surface layer 3," and redundant explanations are omitted. The fiber aggregate layer prepreg is positioned inside the surface layer 3 and contains carbon fibers oriented at an angle greater than 0 degrees and less than 90 degrees with respect to the orientation direction of one of the carbon fibers constituting the carbon fiber fabric, and is impregnated with a thermosetting resin. The fiber aggregate layer prepreg corresponds to the "inner layer carbon fiber prepreg 5A" described in section "1. Fiber-reinforced molded body 1 (2) Fiber aggregate layer 5", and redundant explanations are omitted. The foamed layer prepreg contains a resin foam and is impregnated with a thermosetting resin. The foamed layer prepreg corresponds to the "Foamed Prepreg 7A" described in section "1. Fiber-reinforced molded body 1 (3) Resin foam layer 7," so redundant explanations are omitted. The number of layers of each of the carbon fiber prepreg for the surface layer 3A (prepreg for the surface layer), carbon fiber prepreg for the inner layer 5A (prepreg for the fiber aggregate layer), and foam prepreg 7A (prepreg for the foam layer) is set appropriately according to the application of the fiber-reinforced molded body 1 and the required strength, etc. Furthermore, the prepreg for forming three-dimensional objects may also include the "carbon fiber prepreg 13A for intermediate layer" described in the section "1. Fiber-reinforced molded body 1 (4.2) Other carbon fiber layers as intermediate layer 13". The prepreg for molding three-dimensional objects of this disclosure provides a three-dimensional fiber-reinforced molded body 1 having sharply bent portions 17 without the breakage of carbon fibers.

[0030] 3. Method for manufacturing fiber-reinforced molded body 1 An example of a method for manufacturing a fiber-reinforced molded body 1 is shown. In this manufacturing method, as shown in Figure 2, at least one of a recess and a convex portion is formed on the mold surface of at least one of the pressurized molds 40, which is the lower pressurized mold 41 and the upper pressurized mold 43. A prepreg for molding a three-dimensional object is placed between the lower pressurized mold 41 and the upper pressurized mold 43. Then, the prepreg for molding a three-dimensional object is pressed and heated by the lower pressurized mold 41 and the upper pressurized mold 43 to cure the thermosetting resin and form a three-dimensional shape on the surface layer 3 having a sharply bent portion 17 by the mold surface. In this manufacturing method, the carbon fiber prepreg 3A for the surface layer (prepreg for the surface layer), the carbon fiber prepreg 5A for the inner layer (prepreg for the fiber aggregate layer), and the foamed prepreg 7A (prepreg for the foamed layer) are integrated and their shapes are fixed, and a fiber-reinforced molded body 1 is obtained. The prepregs for molding three-dimensional objects are described in the section "2. Prepregs for molding three-dimensional objects" above.

[0031] The recesses and protrusions of the pressure mold 40 form the three-dimensional shape of the fiber-reinforced molded body 1. The amount of compression of the foam prepreg 7A is adjusted by the depth of the recesses and the height of the protrusions of the pressure mold 40, thereby controlling the thickness of each part of the fiber-reinforced molded body 1.

[0032] The manufacturing method illustrated in Figure 2 is suitable for manufacturing the front 19 of an eyeglass frame. As shown in Figure 2, a lower pressurized mold 41 has a projection 41A for forming the back of the front 19 formed on its mold surface, and an upper pressurized mold 43 has a recess 43A for forming the front of the front 19 formed on its mold surface. The pre-cured carbon fiber prepreg for the surface 3A, carbon fiber prepreg for the inner layer 5A, carbon fiber prepreg for the inner layer 5A, foamed prepreg 7A, carbon fiber prepreg for the intermediate layer 13A, foamed prepreg 7A, carbon fiber prepreg for the intermediate layer 13A, carbon fiber prepreg for the surface 3A, carbon fiber prepreg for the surface 3A, and carbon fiber prepreg for the surface 3A are stacked in this order between the lower pressurized mold 41 and the upper pressurized mold 43, and each stacked prepreg is pressed and heated. The lower pressure type 41 and the upper pressure type 43 are heated to a temperature at which the thermosetting resin can be cured by a heating means such as an electric heater. According to the manufacturing method of the fiber reinforced molded body 1 of the present disclosure, a three-dimensional fiber reinforced molded body 1 having a bent portion 17 bent at an acute angle without breakage of carbon fibers is provided.

Example

[0033] 1. Example An example of manufacturing the front 19 of the glasses frame in FIG. 3 is shown. (1) Preparation of prepreg (1.1) Carbon fiber prepreg 3A for surface layer As the thermosetting resin, a phenol resin (manufactured by Asahi Organic Materials Co., Ltd., product name: PAPS-4 and Asahi Organic Materials Co., Ltd., product name: hexamethylenetetramine mixed at 100:12) was dissolved in methanol to a concentration of 30% by mass. In this phenol resin solution, a plain weave carbon fiber fabric (manufactured by Toray Industries, Inc., fiber weight 92 g / m 2 , thickness 0.1 mm) was immersed, taken out, and then naturally dried at room temperature of 25 °C for 2 hours, and further dried in an atmosphere of 60 °C for 1 hour to form 4 sheets of carbon fiber prepreg 3A for surface layer.

[0034] (1.2) Carbon fiber prepreg 5A for inner layer In the same manner as the carbon fiber prepreg 3A for surface layer, 2 sheets of carbon fiber prepreg 5A for inner layer were formed. The carbon fiber prepreg 5A for inner layer is the same as the carbon fiber prepreg 3A for surface layer in terms of material. In the laminated state described later, the direction of the carbon fibers of the carbon fiber prepreg 5A for inner layer is different from the direction of the carbon fibers of the carbon fiber prepreg 3A for surface layer, and the fiber orientation directions of both intersect. "

[0035] (1.3) Foam prepreg 7A As the foam prepreg 7A, a melamine resin foam having a continuous cell structure with air permeability (manufactured by BASF, product name: Basotect G+, thickness 5.0 mm, density 9.2 kg / m 3 , without skin layer, tensile strength 149 KPa, elongation 24%) impregnated and dried with the above phenol resin in advance was used.

[0036] (1.4) Carbon fiber prepreg 13A for intermediate layer A twill weave carbon fiber fabric (manufactured by Teijin Limited, fiber weight 200 g / m²) is placed in the above phenol resin solution. 2 A 0.25mm thick layer was immersed in the mixture, removed, and then air-dried at room temperature (120°C) for 3 minutes to form two sheets of carbon fiber prepreg 13A for the intermediate layer.

[0037] (1.5) Porous sheet 4 A porous sheet 4 was placed on one side of each of the carbon fiber prepregs: carbon fiber prepreg 3A for the surface layer, carbon fiber prepreg 5A for the inner layer, and carbon fiber prepreg 13A for the intermediate layer, all of which contain carbon fibers. As the porous sheet 4, a breathable, open-cell urethane resin foam (manufactured by Inoac Corporation, product name: MF-50LE, bulk density 0.03, cell count 50 / 25mm, thickness 0.7mm) was used.

[0038] (2) Lamination and heating As shown in Figure 2, each prepreg was laminated and heated in a lower press mold 41 and an upper press mold 43, which have cavities, to obtain a fiber-reinforced molded body 1. Specifically, each prepreg was laminated and arranged on the cavity of the SUS lower press mold 41, which had a release agent applied to its surface in advance, in the following lamination order shown in Figure 2. Note that "0 degrees," which is the reference point for the orientation of the carbon fiber fabric, is based on the lateral direction of the front 19 of the eyeglass frame, as shown in Figure 3. <Layer 1> Carbon fiber prepreg 3A for surface layer with plain weave carbon fiber fabric oriented at +0 / -90 degrees <Layer 2, Layer 3> 5A carbon fiber prepreg for inner layer with a plain weave carbon fiber fabric oriented ±45 degrees <4th layer> Foam prepreg 7A <5th layer> Carbon fiber prepreg 13A for intermediate layer with twill weave carbon fiber fabric oriented at +0 / -90 degrees <6th layer> Foam prepreg 7A <7th layer> Carbon fiber prepreg 13A for intermediate layer with twill weave carbon fiber fabric oriented at +0 / -90 degrees <Layers 8, 9, and 10> Carbon fiber prepreg 3A for surface layer with plain weave carbon fiber fabric oriented at +0 / -90 degrees

[0039] The laminate on the lower pressurized mold 41 was compressed and heated by the upper pressurized mold 43 at 180°C for 3 minutes under a surface pressure of 5 MPa, thereby curing the phenolic resin in a compressed state. The heating was performed using casting heaters attached to the upper and lower molds. The three-dimensional shape and the thickness of each part after compression were adjusted by cavities designed according to the product shape. After the upper and lower molds cooled to room temperature, they were opened to obtain a fiber-reinforced molded body 1. The fiber-reinforced molded body 1 was trimmed to form the front 19 of the eyeglass frame. The front 19 has a sharply bent section 17 (bending angle of approximately 45 degrees). There was no breakage of carbon fibers in the bent section 17, and it had a clean appearance.

[0040] 2. Comparative Example A fiber-reinforced molded body 1 was obtained in the same manner as in the example, except that a carbon fiber prepreg 3A for the surface layer, which had a plain weave carbon fiber fabric with a +0 / -90 degree orientation, was used as the second and third layers. At the bent portion 17 of the front 19, the carbon fibers of the surface layer 3 were broken, resulting in a poor appearance.

[0041] 3. Effects of the Examples The front 19 of the eyeglass frame in this embodiment has a sharply bent portion 17, which increases the design freedom. Even in the sharply bent portion 17, there is no breakage of the carbon fiber, resulting in a clean appearance.

[0042] This disclosure is not limited to the embodiments detailed above, and three-dimensional shapes having a bending angle of 88 degrees and three-dimensional shapes having a bending angle of 89 degrees can also be formed in the same manner, and various modifications or changes are possible within the scope of this disclosure. Furthermore, the technology disclosed herein can similarly form three-dimensional shapes having a bending angle of 98 degrees, and three-dimensional shapes having a bending angle of 30 degrees or more and 98 degrees. [Explanation of Symbols]

[0043] 1 ... Fiber-reinforced molded body 3…Surface layer 3A…Carbon fiber prepreg for surface layer 3B ... Carbon fiber fabric 4…Porous sheet 5 ... Fiber aggregate layer 5A ... Carbon fiber prepreg for inner layer 5B…Aggregation 7 ... Resin foam layer 7A ... Foam prepreg 11 ... Surface layer on the reverse side 11A...1st back side surface layer 11B…Second back side surface layer 11C…Third back side surface layer 13…Middle class 13A…Carbon fiber prepreg for intermediate layer 13B…Carbon fiber fabric 17 ...Bend 19… Front 21…rim 23...Connection part 25…Side 1 27…Second side 29 ... corner 31 ... Press direction 40... Pressurized type 41…Lower pressure type 41A…Protrusion for forming the back surface 43...Upper pressure type 43A…Recess for forming the front surface F...Carbon fiber

Claims

1. A surface layer containing carbon fiber fabric, A fiber aggregate layer containing carbon fibers arranged inside the surface layer and oriented at an angle greater than 0 degrees and less than 90 degrees with respect to the orientation direction of one of the carbon fibers constituting the carbon fiber fabric, A spectacle frame comprising a resin foam layer, It is integrated by a cured thermosetting resin, It has a three-dimensional shape with sharply bent sections, In the bent portion, the surface layer and the fiber aggregate layer are laminated together. In the aforementioned bent portion, the surface layer of the eyeglass frame is bent at a sharp angle.

2. A surface layer containing carbon fiber fabric, A fiber aggregate layer containing carbon fibers arranged inside the surface layer and oriented at an angle greater than 0 degrees and less than 90 degrees with respect to the orientation direction of one of the carbon fibers constituting the carbon fiber fabric, A fiber-reinforced molded article comprising a resin foam layer, It is integrated by a cured thermosetting resin, It has a three-dimensional shape with sharply bent sections, In the bent portion, the surface layer and the fiber aggregate layer are laminated together. The bent portion has a first surface and a second surface where the surface layers are connected at an acute angle, The second surface is a surface aligned with the pressing direction, A fiber-reinforced molded body in which the maximum width of the second surface is 1 mm or more and 5 mm or less.

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