Carbon fiber reinforced resin sheet and method for manufacturing the same

Abstract

To provide a carbon fiber-reinforced resin sheet having less color shading of coloration and having excellent designability.SOLUTION: A carbon fiber-reinforced resin sheet 1 includes: a prepreg sheet 2 including a thermoplastic resin film 11 and a carbon fiber 12 contained in a state of being oriented in the same direction in the resin film 11; and a metallic luster layer 3 that covers at least one surface of the prepreg sheet 2. The metallic luster layer 3 is a metal coating adhered to the prepreg sheet 2 by, for example, dry plating.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a carbon fiber reinforced resin sheet and a method for producing the same.

Background Art

[0002] Carbon fiber reinforced resin (hereinafter referred to as CFRP) containing carbon fiber as a reinforcing fiber may be used as an alternative to metal. However, since CFRP generally has a monotonous black color tone and does not have a luster like metal, it is inherently unsuitable for use as a design part.

[0003] In order to use CFRP as described above as a design part, for example, as in Patent Documents 1 to 3 below, it has been proposed to color CFRP.

[0004] Patent Document 1 discloses coloring the surface of CFRP (fiber reinforced prepreg) using a spraying device for spraying a coloring agent.

[0005] Patent Document 2 discloses forming CFRP (colored prepreg) by impregnating carbon fiber with a matrix resin containing a coloring agent.

[0006] Patent Document 3 discloses attaching a sizing agent containing a coloring agent to carbon fiber and forming CFRP (carbon fiber reinforced composite material) using the colored carbon fiber thus obtained.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

[0008] However, none of the coloring methods described in Patent Documents 1 to 3 may sufficiently improve the aesthetic appeal of CFRP. For example, in the method of painting CFRP as described in Patent Document 1, there is a risk that the paint may peel off. In the method of incorporating a colorant into the matrix resin as described in Patent Document 2, there is a risk of uneven coloring if the dispersion of the colorant is insufficient. In the method of attaching a colorant to carbon fibers as described in Patent Document 3, the black color of the carbon fibers may inhibit color development, resulting in a dull color.

[0009] This invention has been made in view of the above circumstances, and aims to provide a carbon fiber reinforced resin sheet with less color unevenness and excellent design. [Means for solving the problem]

[0010] To solve the above problems, the carbon fiber reinforced resin sheet according to the first invention of this application comprises a prepreg sheet containing a thermoplastic resin film and carbon fibers contained in the resin film in the same direction, and a metallic gloss layer covering at least one surface of the prepreg sheet. The total thickness of the prepreg sheet and the metallic gloss layer is 60 μm or less, and the prepreg sheet is made of the resin film and 40 g / m² on both sides of the resin film. 2 The carbon fibers are laminated in the following basis weights, It is.

[0011] According to this first invention, the blackish tones of the prepreg sheet can be covered by the metallic gloss layer, and a vivid metallic luster can be imparted to the surface of the carbon fiber reinforced resin sheet. As a result, a carbon fiber reinforced resin sheet with less color unevenness and superior design can be realized. Furthermore, because the total thickness of the prepreg sheet and the metallic gloss layer is extremely thin, at 60 μm or less, it is possible to realize a carbon fiber reinforced resin sheet with high flexibility and excellent shape conformability. Such a carbon fiber reinforced resin sheet can be suitably used, for example, as a decorative sheet to be attached to the surface of an object to be decorated. Furthermore, the basis weight of the carbon fiber is 40g / m 2 As a result, the degree of overlap of the carbon fibers can be reduced, thereby keeping the thickness of the carbon fiber laminate low. This allows for a reduction in the thickness of the prepreg sheet, making it possible to manufacture very thin carbon fiber reinforced resin sheets.

[0012] Preferably, the metallic luster layer is a metal film attached to the prepreg sheet by dry plating.

[0013] The metal gloss layer formed by dry plating has properties of being heat-resistant and having little deterioration due to rubbing. A carbon fiber reinforced resin sheet including such a metal gloss layer can maintain sufficient designability even when subjected to press molding or injection molding. Therefore, by subjecting the carbon fiber reinforced resin sheet to press molding or injection molding, a composite molded product having excellent designability can be manufactured.

[0018] The carbon fiber reinforced resin sheet according to the second invention of the present application includes a plurality of prepreg pieces having a thermoplastic resin film and carbon fibers contained in the resin film in an oriented state in the same direction, and the prepreg pieces are randomly and sheet-like. It is provided with a chopped sheet material that is assembled and integrated, and a metal gloss layer that covers at least one surface of the chopped sheet material.

[0019] According to this second invention, similar to the first invention described above, a vivid metal gloss can be imparted to the surface of the carbon fiber reinforced resin sheet, and color unevenness can be suppressed. Further, since the direction of the carbon fibers becomes random, pseudo-isotropy can be imparted to the carbon fiber reinforced resin sheet.

[0020] The manufacturing method of the carbon fiber reinforced resin sheet according to the third invention of the present application is to heat and pressurize carbon fibers oriented in one direction on a thermoplastic resin film both sides to obtain a prepreg sheet including the resin film and the carbon fibers contained therein 1 step, and forming a metal gloss layer by adhering a metal by dry plating on at least one surface of the obtained prepreg sheet 2nd step, and includes Furthermore, 40 g / m² is applied to both sides of the aforementioned resin film. 2 The first step is carried out so that the carbon fibers are laminated with the following basis weights, and the first and second steps are carried out so that the total thickness of the prepreg sheet and the metallic luster layer is 60 μm or less. is what it is.

[0021] According to this third invention, a carbon fiber reinforced resin sheet with vivid metallic luster on the surface and little color unevenness can be produced. Further, it is possible to prevent the metallic luster from being impaired by heat or rubbing, and the design property can be maintained well.

[0022] The method for manufacturing a carbon fiber reinforced resin sheet according to the fourth invention of the present application includes the steps of obtaining a prepreg sheet including the resin film and the carbon fibers contained therein by heating and pressing the carbon fibers oriented in one direction onto a thermoplastic resin film; cutting the obtained prepreg sheet into short pieces to obtain a plurality of prepreg pieces; randomly spreading the obtained prepreg pieces and heating and pressing them to obtain a chopped sheet material in which the prepreg pieces are assembled and integrated into a sheet shape; and forming a metallic luster layer by adhering a metal to at least one surface of the obtained chopped sheet material by dry plating.

[0023] According to this fourth invention, similarly to the above-described third invention, a carbon fiber reinforced resin sheet excellent in design property can be produced. Further, pseudo-isotropy can be imparted to the carbon fiber reinforced resin sheet.

Effects of the Invention

[0024] As described above, according to the present invention, a carbon fiber reinforced resin sheet with little coloring unevenness and excellent in design property can be provided.

Brief Description of the Drawings

[0025] [Figure 1] It is a schematic cross-sectional view showing the structure of a carbon fiber reinforced resin sheet according to the first embodiment of the present invention. [Figure 2] It is a flowchart showing a schematic procedure of the method for manufacturing the above carbon fiber reinforced resin sheet. [Figure 3] It is a perspective view showing a schematic configuration of an apparatus for molding a prepreg sheet. [Figure 4]This is a cross-sectional view showing the schematic configuration of an apparatus for forming a metallic luster layer on the surface of the above-mentioned prepreg sheet. [Figure 5] This is a schematic cross-sectional view showing the structure of a carbon fiber reinforced resin sheet according to a second embodiment of the present invention. [Figure 6] This flowchart outlines the general procedure for manufacturing the carbon fiber reinforced resin sheet described above. [Figure 7] This is a schematic perspective view illustrating a method for forming chopped sheet material. [Modes for carrying out the invention]

[0026] (1) First Embodiment [Structure of carbon fiber reinforced resin sheet] Figure 1 is a schematic cross-sectional view showing the structure of a carbon fiber reinforced resin sheet 1 according to a first embodiment of the present invention. As shown in this figure, the carbon fiber reinforced resin sheet 1 comprises a prepreg sheet 2 and a metallic gloss layer 3 covering the surface of the prepreg sheet 2. The prepreg sheet 2 includes a thermoplastic resin film 11 and carbon fibers 12 contained in the resin film 11. The metallic gloss layer 3 is a metallic coating attached to the surface of the prepreg sheet 2. In other words, the carbon fiber reinforced resin sheet 1 in this embodiment is a thermoplastic composite material whose surface is covered with a metallic gloss layer 3. Hereinafter, the carbon fiber reinforced resin sheet 1 will be appropriately abbreviated as CFRTP sheet 1.

[0027] The thickness d of the CFRTP sheet 1, that is, the total thickness of the prepreg sheet 2 and the metallic luster layer 3, is set to be between 30 μm and 60 μm.

[0028] The resin film 11 is an extremely thin sheet having a certain thickness and width. The resin film 11 is formed, for example, by extrusion molding of a thermoplastic resin. The thickness of the resin film 11 is set to be between 10 μm and 40 μm.

[0029] As the thermoplastic resin that is the material for the resin film 11, that is, the matrix resin of the prepreg sheet 2, for example, polyamide (especially PA6, PA9T, PA12), polyethylene, polypropylene, polyphenylene sulfide, polyolefin, polyester, polyacetal, polycarbonate, acrylic resin, acrylonitrile-butadiene-styrene copolymer (ABS), polyamide-imide, polysulfone, polyphenyl sulfone, polyetherimide, polyethersulfone, polyetherether ketone, polyether ketone ketone, polyimide, polyarylate, fluororesin, liquid crystal polymer, thermoplastic epoxy resin, etc., can be used. Alternatively, a polymer alloy obtained by mixing two or more of these thermoplastic resins may be used as the material for the resin film 11.

[0030] The carbon fibers 12 are continuous carbon fibers, laminated and fixed to both sides of the resin film 11 in the thickness direction. Specifically, the carbon fibers 12 are laminated to both sides of the resin film 11 in a state where they are oriented in a certain direction along the longitudinal direction of the resin film 11 (the direction perpendicular to the plane of the paper in Figure 1). In addition, the carbon fibers 12 are arranged side by side with close spacing in the width direction of the resin film 11 so that they form an extremely thin strip overall. For convenience, Figure 1 shows the carbon fibers 12 arranged side by side so that they do not overlap in the thickness direction of the resin film 11, but the carbon fibers 12 only need to spread in the width direction so as to cover almost the entire surface of the resin film 11, and they may be arranged in a state where they overlap to some extent.

[0031] As the carbon fiber 12, PAN (polyacrylonitrile) or pitch-based carbon fibers can be suitably used. From the viewpoint of obtaining sufficient reinforcement effect from the carbon fiber 12, high-strength PAN-based carbon fibers are more preferable. The fiber diameter of the carbon fiber 12 is set to 5 μm or more and 12 μm or less. In addition, the basis weight of the carbon fiber 12, that is, the weight of the carbon fiber 12 per unit area, is 10 g / m². 2 More than 40g / m 2The following settings are applied. In other words, the carbon fiber 12 is applied to both sides (top and bottom) of the resin film 11, with a basis weight of 10 to 40 g / m² each. 2 They are layered in such a way.

[0032] In this embodiment, the prepreg sheet 2 is a semi-impregnated type in which carbon fibers 12 are partially embedded in the resin film 11. That is, the prepreg sheet 2 in this embodiment has a resin film 11 and carbon fibers 12 laminated and fixed so as to be partially embedded on both sides of the resin film 11. In other words, the carbon fibers 12 are embedded in the surface layer of the resin film 11 in such a way that a portion of them is exposed on the outside of the resin film 11, and are not completely embedded inside the resin film 11.

[0033] The metallic luster layer 3 is formed by dry plating applied to the surface of the prepreg sheet 2. Dry plating is a plating method in which vaporized metal is deposited onto an object, such as vapor deposition (vacuum deposition) and sputtering. As is well known, vapor deposition is a method in which a film-forming material (metal) is heated in a vacuum chamber using an electron beam or laser to vaporize the metal, and the vaporized metal is deposited onto the surface of the object. Sputtering is a method in which a high voltage is applied to ionize a rare gas element, which is then collided with a film-forming material (metal) in a vacuum chamber to vaporize the metal, and the vaporized metal is deposited onto the surface of the object.

[0034] In the example shown in Figure 1, the metallic luster layer 3 is formed on only one surface (the top surface) in the thickness direction of the prepreg sheet 2. However, the metallic luster layer 3 only needs to be formed on at least one surface of the prepreg sheet 2, and the metallic luster layer 3 may be formed on both sides of the prepreg sheet 2.

[0035] The metal material for the metallic luster layer 3 can be any type as long as it is suitable for dry plating and produces a glossy finish, but aluminum, chromium, nickel, zinc, tin, gold, silver, copper, platinum, etc. are preferred.

[0036] [Manufacturing method] Next, a method for manufacturing the CFRTP sheet 1 having the structure described above will be explained. Figure 2 is a flowchart illustrating the schematic procedure of the manufacturing method. As shown in this figure, the manufacturing method for the CFRTP sheet 1 includes a sheet molding step S1 for molding a prepreg sheet 2, and a plating step S2 for forming a metallic luster layer 3 on the surface of the molded prepreg sheet 2 by dry plating.

[0037] (Sheet forming process) Figure 3 is a diagram illustrating the details of the sheet molding process S1 and is a perspective view showing the schematic configuration of the sheet molding apparatus 50 that molds the prepreg sheet 2. The sheet molding apparatus 50 shown in this figure is an apparatus that continuously molds the prepreg sheet 2 from a fiber bundle 12A, which is a bundle of carbon fibers, and a thermoplastic resin film 11.

[0038] Specifically, the sheet forming apparatus 50 comprises multiple pairs (in this case, two pairs) of heating rollers 51 arranged vertically, multiple pairs (in this case, two pairs) of cooling rollers 52 arranged vertically below the heating rollers 51, a pair of endless belts 54 wrapped between the heating rollers 51 and the cooling rollers 52, a pair of pull-out rollers 55 positioned below the endless belts 54, and a winding bobbin 56 positioned below the pull-out rollers 55.

[0039] On both sides of the uppermost heating roller 51, there are fiber-opening mechanisms (not shown) that open the fiber bundles 12A and spread them out into a strip. This fiber-opening mechanism makes it possible to form a large number of continuous carbon fibers 12 that are spread out into a thin strip by continuously opening the fiber bundles 12A. Any mechanism capable of such processing can be used as the fiber-opening mechanism, and various mechanisms can be used, such as a mechanism that spreads the fiber bundles by beating them, a mechanism that spreads the fiber bundles by blowing air on them, or a mechanism that spreads the fiber bundles by applying ultrasonic waves.

[0040] In the example shown in Figure 3, the fiber-opening mechanism includes a mechanism for supplying the opened carbon fibers 12 to one side of the resin film 11 and a mechanism for supplying the opened carbon fibers 12 to the other side of the resin film 11. Through these mechanisms, the carbon fibers 12 are introduced between one side of the resin film 11 and the heating roller 51 in contact with it, and between the other side of the resin film 11 and the heating roller 51 in contact with it.

[0041] The heating roller 51 is a high-temperature roller heated by an electric heater or a heating medium. The heating roller 51 applies pressure and heat by sandwiching the resin film 11 and the carbon fibers 12 arranged in layers on both sides therefrom via an endless belt 54. As a result, the carbon fibers 12 are continuously incorporated into the resin film 11 in a state where they are aligned in the same direction (up and down direction in Figure 2).

[0042] The cooling roller 52 is a low-temperature roller cooled by a cooling medium or the like. The cooling roller 52 pressurizes and cools the resin film 11 containing carbon fibers 12 by sandwiching it from both sides via an endless belt 54. As a result, the carbon fibers 12 are fixed to the resin film 11, and a prepreg sheet 2 is formed in which the carbon fibers 12 are laminated and integrated on both sides of the resin film 11.

[0043] The pull-out roller 55 is a roller that applies tension to the molded prepreg sheet 2 and pulls it downward.

[0044] The winding bobbin 56 is a core material for winding the prepreg sheet 2. The bobbin 56 is rotationally driven by a drive source such as a motor, and sequentially winds the prepreg sheet 2 that has been pulled out by the pull-out roller 55, thereby bundling the prepreg sheet 2 into a roll.

[0045] As described above, in this embodiment, a semi-impregnated type prepreg sheet 2 is used. Therefore, in the sheet molding apparatus 50, the heating temperature by the heating roller 51 and the pressure applied by the heating roller 51 and the cooling roller 52 are set to values ​​such that the carbon fibers 12 are partially embedded on both sides of the resin film 11 (so that a portion of the carbon fibers 12 are exposed to the outside of the resin film 11).

[0046] (Plating process) Figure 4 is a diagram illustrating the details of the plating process S2, and is a cross-sectional view showing the schematic configuration of a plating apparatus 60 that forms a metallic luster layer 3 on the surface of a prepreg sheet 2. As shown in this figure, the plating apparatus 60 comprises a vacuum chamber 61, a film-forming material 62 placed inside the vacuum chamber 61, and a vaporizer (not shown) that vaporizes the metal from the film-forming material 62.

[0047] The prepreg sheet 2 formed by the sheet molding process S1 described above is cut to an appropriate length that can be accommodated in the vacuum chamber 61, and then placed in a position opposite the film-forming material 62 inside the vacuum chamber 61.

[0048] The film-forming material 62 is the source of the metal that constitutes the metallic luster layer 3. The vaporization device vaporizes the metal from the film-forming material 62 and deposits the vaporized metal onto the surface of the prepreg sheet 2. The method of vaporizing the metal may be to heat the film-forming material 62 by irradiation with an electron beam or laser (deposition), or to collide ionized noble gas elements with the film-forming material 62 under high voltage (sputtering). The metal vaporized from the film-forming material 62 is blown toward the surface of the prepreg sheet 2 opposite to the film-forming material 62, as shown by the arrow in Figure 4, and adheres to that surface. As a result, a metallic luster layer 3 (Figure 1) is formed on one surface of the prepreg sheet 2. That is, a CFRTP sheet 1 including the prepreg sheet 2 and the metallic luster layer 3 covering its surface is manufactured.

[0049] Furthermore, when forming the metallic luster layer 3 on both sides of the prepreg sheet 2, one side of the prepreg sheet 2 can be treated with the film deposition process as described above, and then the other side of the prepreg sheet 2 can be treated with the film deposition process in the same manner.

[0050] [Effects and Effects] As described above, the CFRTP sheet 1 according to the first embodiment of the present invention includes a prepreg sheet 2 and a metallic gloss layer 3 covering it. Therefore, the blackish color tone of the prepreg sheet 2 can be covered by the metallic gloss layer 3, and a vivid metallic gloss can be given to the surface of the CFRTP sheet 1. This makes it possible to realize a CFRTP sheet 1 with less color unevenness and excellent design.

[0051] In particular, in the first embodiment described above, since the metallic luster layer 3 is formed by dry plating, it is possible to suppress the loss of metallic luster due to heat and friction. That is, the metallic luster layer 3 formed by dry plating has the properties of being heat resistant and less prone to deterioration due to friction. A CFRTP sheet 1 containing such a metallic luster layer 3 can maintain sufficient design even when subjected to press molding or injection molding. Therefore, by subjecting the CFRTP sheet 1 to press molding or injection molding, a composite molded product with excellent design can be manufactured.

[0052] Furthermore, in the first embodiment described above, the thickness d of the CFRTP sheet 1, which is the total thickness of the prepreg sheet 2 and the metallic gloss layer 3, is set to 60 μm or less, so the CFRTP sheet 1 can be suitably used as a decorative sheet. In other words, the CFRTP sheet 1, with a very small thickness d of 60 μm or less, is highly flexible and has excellent shape conformability, so it can be suitably used as a decorative sheet to be attached to the surface of an object to be decorated.

[0053] Furthermore, in the first embodiment described above, the basis weight of the carbon fiber 12 relative to the prepreg sheet 2 is 40 g / m². 2 The following setting allows us to suppress the thickness d of the CFRTP sheet 1. Specifically, the basis weight of the carbon fiber 12 is 40 g / m². 2The following means that the degree of overlap of the carbon fibers 12 is small, and the thickness of the carbon fiber lamination 12 can be kept small. As a result, the thickness of the prepreg sheet 2 can be reduced, and a very thin CFRTP sheet 1 can be manufactured.

[0054] [Differentiation] In the first embodiment described above, a prepreg sheet 2 was used in which carbon fibers 12 were laminated and fixed on both sides of a resin film 11. However, the carbon fibers 12 may be laminated on only one side of the resin film 11. In this case, it is preferable that the metallic gloss layer 3 be formed to cover the side on which the carbon fibers 12 are laminated.

[0055] In the first embodiment described above, an example was described in which carbon fibers 12 were laminated so as to be partially embedded in the surface of the resin film 11 (see Figure 1). However, the carbon fibers 12 may also be completely embedded inside the resin film 11 (so as to be hardly exposed to the outside). In other words, the prepreg sheet 2 is not limited to the semi-impregnated type used in the first embodiment above, but may also be a fully impregnated type. When forming a fully impregnated type prepreg sheet, the carbon fibers may be embedded from both sides of the resin film, or from only one side of the resin film.

[0056] (2) Second Embodiment In the first embodiment described above, the surface of the prepreg sheet 2 containing carbon fibers 12 oriented in the same direction was coated with a metallic luster layer 3. However, it is also possible to coat the surface of a molded body formed from a similar prepreg sheet with a metallic luster layer. Below, an example of a CFRTP sheet obtained in this way will be described as a second embodiment.

[0057] Figure 5 is a schematic cross-sectional view showing the structure of a CFRTP sheet (carbon fiber reinforced resin sheet) 101 according to the second embodiment. As shown in this figure, the CFRTP sheet 101 comprises a chopped sheet material 102 formed from a prepreg sheet 2 (Figure 3) and a metallic gloss layer 103 covering the surface of the chopped sheet material 102.

[0058] The chopped sheet material 102 is a sheet-like molded body obtained by assembling and integrating a large number of prepreg pieces 120 (Figure 7) into a sheet. The prepreg pieces 120 are short pieces of prepreg cut from the prepreg sheet 2 shown in the first embodiment above.

[0059] The metallic luster layer 103 is the same as the metallic luster layer 3 shown in the first embodiment above, and is a metallic film formed on the surface of the chopped sheet material 102 by dry plating. In Figure 5, the metallic luster layer 103 is formed only on one surface (the top surface) in the thickness direction of the chopped sheet material 102, but it is also possible to form the metallic luster layer 103 on both sides of the chopped sheet material 102.

[0060] The CFRTP sheet 101 described above can be manufactured by the manufacturing method shown in Figure 6. Specifically, the manufacturing method for the CFRTP sheet 101 in the second embodiment includes a first molding step S11 for molding a prepreg sheet 2 (Figure 3), a cutting step S12 for cutting out prepreg pieces 120 (Figure 7) from the molded prepreg sheet 2, a second molding step S13 for molding chopped sheet material 102 from the cut prepreg pieces 120, and a plating step S14 for forming a metallic luster layer 103 (Figure 5) on the surface of the molded chopped sheet material 102.

[0061] In the first molding step S11, carbon fibers 12 are incorporated into the resin film 11 to form a prepreg sheet 2. The contents of this first molding step S11 are the same as those of the sheet molding step S1 described in the first embodiment above.

[0062] In the subsequent cutting process S12, the prepreg sheet 2 obtained in the first molding process S11 is cut in the longitudinal and width directions to form a number of rectangular prepreg pieces 120 (Figure 7). Cutting out such prepreg pieces 120 can be achieved, for example, by an apparatus that includes a longitudinal cutting mechanism that feeds the prepreg sheet 2 in the longitudinal direction and forms a number of cuts in the prepreg sheet 2 that are aligned in the longitudinal direction (aligned in the width direction), and a transverse cutting mechanism that cuts the prepreg sheet 2 in the width direction after the cuts have been formed. Using such an apparatus, a number of rectangular prepreg pieces 120 having a certain width and length are cut out from the prepreg sheet 2. Each prepreg piece 120 contains a rectangular resin film and carbon fibers contained in the resin film that are oriented in the same direction (the longitudinal direction of the resin film).

[0063] In the second molding step S13, the chopped sheet material 102 shown in Figure 7 is formed by laminating and integrating the numerous prepreg pieces 120 obtained in the cutting step S12. In this second molding step S13, the chopped sheet material 102 is formed by randomly laying and fixing numerous prepreg pieces 120 in a two-dimensional manner on the upper surface of a thermoplastic resin carrier sheet 121. Specifically, the chopped sheet material 102 is formed by the following procedure.

[0064] First, as shown in Figure 7, a carrier sheet 121 is fed in its longitudinal direction, and numerous prepreg pieces 120 are dispersed and arranged on the upper surface of the carrier sheet 121. For example, the prepreg pieces 120 are dropped from above the carrier sheet 121 while being vibrated, and this dropping operation is repeated in each section I, II, III, etc. in the feeding direction of the carrier sheet 121, thereby increasing the density and number of layers of prepreg pieces 120 on the carrier sheet 121. As a result, the prepreg pieces 120 are stacked on the carrier sheet 121 with the fiber direction of the carbon fibers 12 contained in each prepreg piece 120 (in other words, the longitudinal direction of the prepreg piece 120) varying in various directions on the horizontal plane, and overlapping each other in the thickness direction.

[0065] Next, the carrier sheet 121 and the prepreg pieces 120 on it are pressurized and heated using a heating roller (not shown in the figure) to integrate the carrier sheet 121 and the prepreg pieces 120 with each other. That is, the pressurization and heating using the heating roller bond (fusion) the carrier sheet 121 and the prepreg pieces 120 together, and also bond (fusion) the stacked prepreg pieces 120 with each other. As a result, a chopped sheet material 102 is obtained in which the carrier sheet 121 and a number of prepreg pieces 120 are integrated. The thickness of the chopped sheet material 102, that is, the total thickness of the carrier sheet 121 and the prepreg pieces 120 stacked on it, is set to approximately 1 mm or less (for example, 0.5 mm). In other words, the number of stacked prepreg pieces 120 is set to a number such that the thickness of the chopped sheet material 102 is approximately 1 mm or less.

[0066] The material of the carrier sheet 121 can basically be the same thermoplastic resin as the matrix resin of the prepreg piece 120. However, as long as it is a thermoplastic resin, carrier sheets 121 of various materials can be used, and a carrier sheet 121 made of a different material from the resin film 11 contained in the prepreg piece 120 (prepreg sheet 2) may also be used.

[0067] Once the chopped sheet material 102 is formed by the second molding process S13 described above, the surface of the chopped sheet material 102 is coated with a metallic luster layer 103 (Figure 5) by dry plating in the subsequent plating process S14. The contents of this plating process S4 are the same as those of the plating process S2 described in the first embodiment above.

[0068] As described above, the CFRTP sheet 101 according to the second embodiment of the present invention includes a chopped sheet material 102 and a metallic gloss layer 103 covering it. Therefore, the blackish color tone of the chopped sheet material 102 can be covered by the metallic gloss layer 3, and a vivid metallic gloss can be imparted to the surface of the CFRTP sheet 101. This makes it possible to realize a CFRTP sheet 101 with less color unevenness and excellent design. In addition, since the direction of the carbon fibers 12 is random, pseudo-isotropy can be imparted to the CFRTP sheet 101.

[0069] In the second embodiment described above, the chopped sheet material 102 was formed by laminating and fixing a large number of prepreg pieces 120 onto a carrier sheet 121 made of thermoplastic resin, but the carrier sheet 121 may be omitted. In other words, it is also possible to form a sheet material 102 consisting only of prepreg pieces 120 that are laminated and fixed to each other. [Explanation of Symbols]

[0070] 1,101 Carbon Fiber Reinforced Polymer Sheet (CFRTP Sheet) 2 Prepreg sheets 3,103 Metallic luster layer 11 Resin film 12 Carbon Fiber 102 Chopped sheet material 120 prepreg pieces

Claims

1. A prepreg sheet comprising a thermoplastic resin film and carbon fibers contained in the resin film in a state oriented in the same direction, The prepreg sheet comprises a metallic gloss layer covering at least one surface, The total thickness of the prepreg sheet and the metallic gloss layer is 60 μm or less. The prepreg sheet is a carbon fiber reinforced resin sheet comprising the resin film and the carbon fibers laminated on both sides of the resin film at a basis weight of 40 g / m² or less.

2. In the carbon fiber reinforced resin sheet according to claim 1, The metallic luster layer is a film of metal attached to the prepreg sheet by dry plating, and the sheet is a carbon fiber reinforced resin sheet.

3. A chopped sheet material comprising a plurality of prepreg pieces having a thermoplastic resin film and carbon fibers contained in the resin film in the same direction, wherein the prepreg pieces are randomly assembled and integrated into a sheet, A carbon fiber reinforced resin sheet comprising a metallic gloss layer covering at least one surface of the chopped sheet material.

4. A first step involves layering unidirectionally oriented carbon fibers on both sides of a thermoplastic resin film and then heating and pressurizing it to obtain a prepreg sheet containing the resin film and the carbon fibers contained therein. The process includes a second step of forming a metallic luster layer by dry plating to deposit metal onto at least one surface of the obtained prepreg sheet, The first step is carried out such that the carbon fibers are laminated on both sides of the resin film at a basis weight of 40 g / m² or less. A method for manufacturing a carbon fiber reinforced resin sheet, comprising carrying out the first and second steps such that the total thickness of the prepreg sheet and the metallic gloss layer is 60 μm or less.

5. The steps include obtaining a prepreg sheet containing the resin film and the carbon fibers contained therein by layering carbon fibers oriented in one direction onto a thermoplastic resin film and heating and pressurizing it, The steps include cutting the obtained prepreg sheet into short pieces to obtain a plurality of prepreg pieces, The steps include: randomly laying out the obtained prepreg pieces and heating and pressurizing them to obtain a chopped sheet material in which the prepreg pieces are assembled and integrated into a sheet; A method for producing a carbon fiber reinforced resin sheet, comprising the step of depositing a metal onto at least one surface of the obtained chopped sheet material by dry plating to form a metallic luster layer.

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