Method for manufacturing resin molded body and resin molded body

Abstract

To provide a method for manufacturing a resin molded body that enables terminal treatment of the resin molded body without using a dedicated cover member.SOLUTION: A method for manufacturing a resin molded body includes: a molding step in which a laminate 11 is formed by laminating a substrate 12 containing fibers and a thermoplastic resin and a colored layer 13 that covers one surface of the substrate 12 and imparts color to light passing through the substrate 12, and cutting an outer periphery 11A of the laminate 11 to form a predetermined product shape; and a welding step in which a protective layer 14 having translucency and waterproof properties is heat-welded to a surface of the colored layer 13 opposite to the substrate 12. In the welding step, the protective layer 14 is adhered to the surface of the colored layer 13 opposite the substrate 12 by vacuum forming and pressure forming, and an outer peripheral end 14D of the protective layer 14 is folded back from the surface of the colored layer 13 opposite the substrate 12 to the other surface of the substrate 12 so as to cover a terminal part 13E of the colored layer 13 and a terminal part 12E of the substrate 12.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The technology disclosed in this specification relates to a method for producing a resin molded product and the resin molded product. [Background technology]

[0002] Conventionally, a resin molded body is known from the following Patent Document 1. Patent Document 1 describes a door trim for a vehicle as the resin molded body, and a cover member is attached to an end portion of the door trim. The end portion of the door trim is treated by covering it with the cover member, so that the passenger does not directly touch the end portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-53305 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the resin molded body of Patent Document 1, a dedicated cover member needs to be attached in order to perform terminal processing. It is also possible to perform terminal processing by covering the terminal portion of the resin molded body with a separate adjacent member. However, in such a configuration, a separate member needs to be adjacent to the terminal portion of the resin molded body, which limits the freedom of design.

[0005] The technology disclosed in this specification has been completed based on the above circumstances, and has an object to provide a manufacturing method for a resin molded body that allows terminal treatment of the resin molded body to be performed without using a dedicated cover member. It is also an object to provide a resin molded body that allows terminal treatment of the resin molded body to be performed without using a dedicated cover member. [Means for solving the problem]

[0006] As a means for solving the above-mentioned problems, the manufacturing method of a resin molded body disclosed in the present specification includes a molding process in which a laminate including a substrate containing fibers and a thermoplastic resin and a plate-shaped substrate and a colored layer that covers one side of the substrate and imparts color to light passing through the substrate is cut at the outer periphery to mold the laminate into a predetermined product shape, and a welding process that is performed after the molding process and heat-welds a protective layer having translucency and waterproofness to the side of the colored layer opposite the substrate, wherein the welding process is characterized in that the protective layer is adhered to the side of the colored layer opposite the substrate by at least one of vacuum molding and pressure molding, and at least a portion of the outer periphery of the protective layer is folded back from the side of the colored layer opposite the substrate to the other side of the substrate, thereby covering a terminal portion of the colored layer and a terminal portion of the substrate with at least a portion of the outer periphery of the protective layer.

[0007] The waterproof protective layer can protect the substrate and the colored layer. The peripheral edge of the protective layer covers the terminals of the colored layer and the substrate, allowing the terminals of the resin molded body to be processed without using a dedicated cover member. Furthermore, the colored layer and the translucent protective layer can show the pattern of the substrate surface, including fibers, as a design, thereby improving the design.

[0008] In addition, the protective layer may comprise a waterproof layer that has waterproof properties and covers the surface of the colored layer opposite the substrate, and an adhesive layer that is interposed between the waterproof layer and the colored layer and bonds the waterproof layer to the colored layer, and in the welding process, the protective layer may be heated to a temperature below the melting point of the waterproof layer and above the melting point of the adhesive layer.

[0009] In the welding step, the waterproof layer can be welded to the colored layer via the adhesive layer. In addition, since the waterproof layer is heated at a temperature equal to or lower than its melting point, it is possible to prevent the waterproof layer from melting and deforming.

[0010] In addition, the melting point of the colored layer can be lower than the melting point of the base material, and in the welding process, the colored layer can be heated to a temperature below the melting point of the base material and above the melting point of the colored layer.

[0011] In the welding process, the colored layer is heated to a temperature above its melting point, so that the protective layer and the colored layer can be welded more reliably. In addition, the substrate is heated to a temperature below its melting point, so that the substrate is prevented from melting. This prevents the substrate from being deformed or the odor inside the substrate from leaking out to the outside.

[0012] As a means for solving the above problems, the resin molded body disclosed in the present specification comprises a plate-shaped substrate containing fibers and a thermoplastic resin, a colored layer that imparts color to light passing through and covers one side of the substrate, and a protective layer that is translucent and waterproof and covers the side of the colored layer opposite the substrate, wherein at least a portion of the outer circumferential end of the protective layer is folded back from the side of the colored layer opposite the substrate to the other side of the substrate, thereby covering an end portion of the colored layer and an end portion of the substrate.

[0013] By covering the terminal parts of the colored layer and the base material with the outer peripheral edge of the protective layer, the terminal processing of the resin molded body can be performed without using a dedicated cover member. In addition, by providing the colored layer and having the protective layer be translucent, the pattern of the base material surface containing fibers can be colored and shown as a design, thereby improving the design. Effect of the Invention

[0014] According to the present invention, it is possible to provide a manufacturing method for a resin molded body that enables terminal treatment of the resin molded body without using a dedicated cover member, and the resin molded body. [Brief description of the drawings]

[0015] [Figure 1]FIG. 1 is a diagram showing a base material forming step according to an embodiment of the present invention. [Diagram 2] Diagram showing the heat pressing process [Diagram 3] FIG. 1 is a diagram showing a state in which a laminate is placed between molds in a molding process. [Figure 4] FIG. 13 is a diagram showing a state in which the molding of the laminate is completed in the molding process. [Diagram 5] FIG. 13 is a diagram showing a state in which the protective layer is heated in the welding process. [Figure 6] FIG. 13 is a diagram showing a state in which the colored layer is heated in the welding process. [Figure 7] FIG. 13 is a diagram showing a state in which a protective layer is placed on a colored layer in a welding process. [Figure 8] FIG. 13 is a diagram showing a state in which the formation of the protective layer is completed in the welding process. [Figure 9] FIG. 13 is a diagram showing a state in which a laminate is placed between molds in a comparative example. [Figure 10] FIG. 13 is a diagram showing a state in which molding of a laminate is completed in a comparative example. [Figure 11] FIG. 13 is a diagram showing terminal treatment of a resin molded body in a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] An embodiment of the present invention will be described with reference to Figs. 1 to 11. In this embodiment, a resin molded body used for vehicle interior materials (for example, door trim ornaments, lower boards, etc.) is exemplified. As shown in Fig. 8, the resin molded body 10 includes a plate-shaped base material 12, a colored layer 13, and a protective layer 14. The base material 12 contains fibers and a thermoplastic resin. For example, kenaf fibers are used as the fibers contained in the base material 12, but the type of fibers is not limited thereto. As the fibers used in the base material 12, wood fibers, thermoplastic resin fibers, glass fibers, carbon fibers, etc. may be used. In the base material 12, the fibers are bound by a thermoplastic resin as a binder. Examples of the thermoplastic resin used in the base material 12 include polyester-based resins such as polypropylene and polyethylene.

[0017] The colored layer 13 is provided so as to cover one surface of the base material 12 (the surface facing outward in the resin molded body 10). The colored layer 13 is translucent and colored, and is capable of imparting color to light passing through it. The colored layer 13 is made of, for example, a spunbond nonwoven fabric. The material of the colored layer 13 may be, for example, polypropylene, but is not limited to this. The spunbond nonwoven fabric is a nonwoven fabric produced by a spunbond method.

[0018] The protective layer 14 is disposed in a manner that covers the surface of the colored layer 13 opposite to the substrate 12. The protective layer 14 has translucency. As shown in FIG. 5, the protective layer 14 includes a waterproof layer 14A that has waterproof and deodorizing properties and covers the surface of the colored layer 13 opposite to the substrate 12, an adhesive layer 14B that is interposed between the waterproof layer 14A and the colored layer 13 and bonds the waterproof layer 14A and the colored layer 13, and an adhesive layer 14C that covers the surface of the waterproof layer 14A opposite to the adhesive layer 14B. The thickness of the protective layer 14 (protective film) is set to, for example, about 100 μm, but is not limited thereto. For example, polyamide can be used as the material of the waterproof layer 14A, and for example, polyethylene can be used as the material of the adhesive layers 14B and 14C, but is not limited thereto.

[0019] The adhesive layer 14C is not adhered to other members, but is provided to prevent the protective layer 14 from warping. If an adhesive layer were provided on only one side of the waterproof layer 14A, there would be a concern that the protective layer 14 would warp when heated due to the difference in thermal expansion coefficient between the waterproof layer 14A and the adhesive layer. By providing adhesive layers 14B and 14C of the same material on both the front and back sides of the waterproof layer 14A, it is possible to prevent the protective layer 14 from warping when heated.

[0020] 8, an outer peripheral end 14D of the protective layer is folded back from the surface of the colored layer 13 opposite the base material 12 to the surface of the base material 12 opposite the protective layer 14 (the other surface), thereby covering an end portion 13E of the colored layer 13 and an end portion 12E of the base material 12. In the resin molded body 10, since the colored layer 13 and the protective layer 14 are each translucent, the pattern on the surface of the base material 12 can be seen and can be utilized as a design.

[0021] Next, a manufacturing apparatus for manufacturing the resin molded body 10 will be described. First, a substrate manufacturing apparatus 20 will be described. The substrate manufacturing apparatus 20 (fiber mat manufacturing apparatus) manufactures a plate-shaped fiber mat from a fiber mixture consisting of plant fibers and thermoplastic resin fibers as a binder. As shown in FIG. 1, the substrate manufacturing apparatus 20 includes a fiber supply section 21, a feed conveyor 22, a fiber opening cylinder 23, a blower section 26, a conveyor 27, a suction device 28, and an intertwining device 29.

[0022] The fibers (mixed fibers 17) fed into the fiber supply section 21 and mixed are supplied to the fiber-spreading cylinder 23 by the feed conveyor 22. The fiber-spreading cylinder 23 has a cylindrical cylinder body 23A with a plurality of protrusions 23B on the surface (outer circumferential surface) thereof, and rotates clockwise in FIG. 1 around the central axis L1. The rotating fiber-spreading cylinder 23 is capable of spreading the mixed fibers 17 sent from the feed conveyor 22 by scratching them with the protrusions 23B. As the fiber-spreading cylinder 23 rotates, the mixed fibers 17 are caught on the surface (protrusions 23B) of the fiber-spreading cylinder 23 and transported upward, and are then released into the air by the centrifugal force generated by the rotation of the fiber-spreading cylinder 23. In FIG. 1, the rotation direction of the fiber-spreading cylinder 23 is indicated by an arrow A1.

[0023] A stripper roller 24 and a walker roller 25 are provided on the outer periphery of the spreading cylinder 23, and a plurality of protrusions are formed on the surface of each of them. The walker roller 25 has a function of subjecting the mixed fibers 17 to a spreading process by passing the mixed fibers 17 between the walker roller 25 and the spreading cylinder 23, and the stripper roller 24 has a function of peeling off the mixed fibers 17 adhering to the surface of the walker roller 25.

[0024] A blower unit 26 is disposed downstream of the spreading cylinder 23, and blows air toward the spreading cylinder 23. The spread mixed fibers 17 are scattered by the air blown from the blower unit 26 and fall onto the conveyor 27.

[0025] The conveyor 27 is a mesh conveyor having a mesh shape, and the mixed fibers 17 can be deposited on the upper surface 27A of the conveyor 27. A suction device 28 is disposed below the conveyor 27, and the mixed fibers 17 can be sucked onto the upper surface 27A of the conveyor 27 by sucking air. The conveyor 27 deposits the mixed fibers 17 on the upper surface 27A and conveys the layer of the mixed fibers 17 to the right side of FIG. 1 to form a fiber web 17A. The conveyor 27 conveys the mixed fibers 17 in the direction indicated by the arrow A2. The intertwining device 29 is, for example, a needle punch device, and is configured to intertwining the fibers contained in the fiber web 17A with each other, thereby forming the fiber web 17A into a nonwoven fabric-like substrate 12.

[0026] Next, a press device for hot pressing the substrate 12 and the colored layer 13 to form the laminate 11 will be described. As shown in FIG. 2, the press device 40 is a double-belt press device, and includes a pair of belts 41 and 42 arranged opposite each other, a pair of rollers 41A and 41B for driving the belt 41, a pair of rollers 42A and 42B for driving the belt 42, a heating section 43, and a cooling section 45. The pair of belts 41 and 42 are made of a metal such as stainless steel. The substrate 12 and the colored layer 13 are conveyed to the right side of FIG. 2 by the pair of belts 41 and 42. The opposing distance T2 between the pair of belts 41 and 42 is set to a value smaller than the total thickness T1 of the substrate 12 and the colored layer 13 (the substrate 12 and the colored layer 13 placed on the conveyor 46) before hot pressing. As a result, the thickness of the substrate 12 and the colored layer 13 decreases in the process of passing between the pair of belts 41 and 42. In FIG. 2, the base material 12 before the hot press is indicated by the reference symbol 12D, and the colored layer 13 is indicated by the reference symbol 13D.

[0027] The heating section 43 is provided on each of the pair of belts 41, 42, and can heat the belts 41, 42 by blowing hot air, for example, onto the belts 41, 42. This makes it possible to heat the base material 12 and the colored layer 13 between the pair of belts 41, 42 in the area where the heating section 43 is disposed. Note that the heating method of the heating section 43 is not limited to using hot air. For example, the heating section 43 can be a heater capable of heating the belt 41 (or belt 42).

[0028] The cooling section 45 is provided on each of the pair of belts 41 and 42, and is capable of cooling the belts 41 and 42. As a result, in the arrangement area of ​​the cooling section 45, it is possible to cool the base material 12 and the colored layer 13 between the pair of belts 41 and 42. As the cooling section 45, for example, a water-cooled roller arranged on the inside of the belt 41 (or belt 42) can be exemplified. A refrigerant (for example, cold water) can be circulated inside the cooling section 45, and the belt 41 (or belt 42) is cooled by the cooling section 45 coming into contact with the belt 41 (or belt 42). The heating section 43 is arranged on the upstream side in the conveying direction D1 (right side in FIG. 2) of the base material 12 and the colored layer 13 by the pair of belts 41 and 42, and the cooling section 45 is arranged on the downstream side in the conveying direction D1.

[0029] Next, a description will be given of a molding device 50 for molding the laminate 11. The molding device 50 includes a pair of molding dies 51, 52 for press-molding the laminate 11. The pair of molding dies 51, 52 are configured to be able to approach and move away from each other by a driving device (not shown, for example, an electric motor, an air cylinder, a hydraulic cylinder, etc.), and the pair of molding dies 51, 52 are configured to be able to be closed and opened by moving them toward and away from each other.

[0030] The molding die 51 has a convex portion 51A that protrudes toward the molding die 52. The convex portion 51A has a molding surface 51B. The molding die 52 has a concave portion 52A that is concave corresponding to the convex portion 51A. The concave portion 52A has a molding surface 52B. The distance between the pair of molding dies 51, 52 in the closed state is smaller than the plate thickness of the laminate 11. As a result, when the laminate 11 is pressed with the pair of molding dies 51, 52, the laminate 11 is compressed and molded into a shape that follows the surface shape of the molding surfaces 51B, 52B.

[0031] Next, a description will be given of a molding device 60 for shaping and attaching the protective layer 14 in a shape that follows the surface shape of the laminate 11. As shown in Fig. 6, the molding device 60 includes a molding die 61 on which the laminate 11 is placed, and a box-shaped compressed air box 62 that defines a space S1 together with the outer surface of the molding die 61. The upper surface of the molding die 61 has a shape that follows the shape of the back surface (the outer surface on the substrate 12 side) of the laminate 11, and serves as a placement surface on which the laminate 11 is placed.

[0032] A vacuum chamber 63 is formed inside the molding die 61. A plurality of vacuum suction holes 61A are formed penetrating the upper wall of the molding die 61. The vacuum chamber 63 is connected to a vacuum suction device 64. The vacuum suction device 64 makes it possible to suck air from the vacuum chamber 63, and to make the vacuum chamber 63 in a vacuum state (a state where the pressure is lower than the atmospheric pressure).

[0033] An air vent 65 is formed in the upper part of the compressed air box 62. A compressed air supply device 66 that supplies compressed air into the compressed air box 62 is connected to the air vent 65. By sending compressed air to the space S1 by the compressed air supply device 66, it is possible to make the space S1 in a state where the pressure is higher than the atmospheric pressure.

[0034] Next, a method for producing the resin molded body of this embodiment will be described. The method for producing the resin molded body of this embodiment includes a base material forming step of forming the base material 12 from fibers, a hot pressing step of hot pressing the base material 12 and the colored layer 13 to integrate them into the laminate 11, a molding step of press molding the laminate 11 with a pair of molds 51 and 52, and a welding step of hot welding the protective layer 14 to the surface of the colored layer 13 opposite to the base material 12.

[0035] (Base material formation process) In the substrate forming process, the mixed fibers 17 are laminated in a plate-like state to form a fiber web 17A, and then the fibers contained in the fiber web 17A are bonded together to form the substrate 12. Specifically, as shown in FIG. 1, the mixed fibers 17 supplied from the fiber supply unit 21 to the opening cylinder 23 by the feed conveyor 22 are opened by the rotating opening cylinder 23, and the mixed fibers 17 (opened fibers) discharged from the opening cylinder 23 into the air are deposited on the upper surface 27A of the conveyor 27 in operation. The mixed fibers 17 deposited on the upper surface 27A are transported to the right side of FIG. 1 by the operation of the conveyor 27. Therefore, the deposition of the mixed fibers 17 on the upper surface 27A and the transport of the deposited mixed fibers 17 are continuously performed, thereby forming the fiber web 17A in which the mixed fibers 17 are laminated. Thereafter, the fibers contained in the fiber web 17A are entangled (bonded) together by the entanglement device 29 to form the substrate 12, which is a nonwoven fabric-like fiber mat.

[0036] (Hot pressing process) In the hot pressing process performed after the substrate cutting process, as shown in FIG. 2, the substrate 12 and the colored layer 13 are integrated by hot pressing using a press device 40. Specifically, in a state in which the colored layer 13 is placed on the substrate 12, the substrate 12 and the colored layer 13 are passed between a pair of belts 41, 42 and pressed to reduce the thickness (plate thickness) of the substrate 12 and the colored layer 13. In the hot pressing process, the substrate 12 and the colored layer 13 are heated in the process of passing between the pair of belts 41, 42 heated by a heating section 43. The heating temperature of the substrate 12 and the colored layer 13 in the hot pressing process is set to a temperature at which the thermoplastic resin fibers contained in the substrate 12 and the colored layer 13 melt.

[0037] The substrate 12 and the colored layer 13 heated by the heating section 43 are cooled in the process of passing through the region where the cooling section 45 is arranged in the pair of belts 41, 42. As a result, the molten thermoplastic resin fiber is cooled and solidified, and functions as a binder, and the fibers contained in the substrate 12 and the colored layer 13 are bonded together. As a result, the substrate 12 and the colored layer 13 are integrated to form the laminate 11. In addition, in the heat pressing process, the plate thickness of the substrate 12 is reduced, and as a result, the density increases, and the rigidity of the substrate 12 becomes higher than when it was a fiber mat. In addition, by attaching the colored layer 13 to the substrate 12 in a state where the substrate 12 is a fiber mat with a relatively low density, the colored layer 13 can be sufficiently impregnated into the substrate 12, and the color of the colored layer 13 can be beautifully developed.

[0038] (molding process) In the molding step performed after the hot pressing step, first, as shown in Fig. 3, the laminate 11 is placed between the molding dies 51 and 52. Thereafter, the laminate 11 is heated by a heating means (such as a heater that generates heat when electricity is applied) not shown. This causes the laminate 11 to be in a softened state. The molding dies 51 and 52 are closed around the laminate 11 in the softened state.

[0039] Then, when the closing of the forming dies 51, 52 is completed, the surface of the laminate 11 on the side of the convex portion 51A is formed into a shape following the shape of the forming surface 51B, and the surface on the side of the concave portion 52A is formed into a shape following the shape of the forming surface 52B, as shown in Fig. 4. Furthermore, the outer peripheral portion 11A of the laminate 11 is cut by shearing as the forming dies 51, 52 are closed, and as a result, the laminate 11 is formed into a predetermined product shape.

[0040] (Welding process) In the welding process performed after the heat pressing process, the protective layer 14 is attached so as to cover the colored layer 13. Specifically, as shown in FIG. 5, both sides of the protective layer 14 are heated by a pair of heating devices 31, 31. Here, the protective layer 14 is heated to a temperature below the melting point of the waterproof layer 14A and above the melting points of the adhesive layers 14B, 14C. Also, as shown in FIG. 6, the colored layer 13 is heated by a heating device 32 while the laminate 11 is placed in a mold 61. Here, the colored layer 13 is heated to a temperature below the melting point of the substrate 12 and above the melting point of the colored layer 13. The melting point of the colored layer 13 is lower than the melting point of the substrate 12 (more specifically, the thermoplastic resin contained in the substrate). As the heating devices 31, 32, a hot air supplying device capable of blowing hot air to a heating target can be exemplified.

[0041] Next, as shown in FIG. 7, the protective layer 14 is placed on the upper surface of the colored layer 13, and then the vacuum suction device 64 is operated. As a result, the vacuum chamber 63 is put into a vacuum state, and the protective layer 14 is sucked to the surface side of the mold 61 through the vacuum suction hole 61A. Since the base material 12 and the colored layer 13 have air permeability, it is possible to suck the protective layer 14 with the base material 12 and the colored layer 13 interposed therebetween. At the same time, the compressed air supply device 66 is operated to inject compressed air from the air vent 65 of the compressed air box 62, thereby applying pressure to the upper surface of the protective layer 14.

[0042] 8, the protective layer 14 is formed into a shape following the surface shape of the colored layer 13 and is adhered to the upper surface 13F of the colored layer 13. The outer peripheral end 14D of the protective layer 14 is folded back from the upper surface 13F side of the colored layer 13 to the rear surface 12F side of the substrate 12 and adheres to the rear surface 12F of the substrate 12. As a result, the terminal portion 13E of the colored layer 13 and the terminal portion 12E of the substrate 12 are covered with the outer peripheral end 14D of the protective layer 14.

[0043] That is, in the welding process, the protective layer 14 is adhered to the upper surface 13F (the surface opposite the substrate 12) of the colored layer 13 by vacuum forming and pressure forming, and the outer peripheral end 14D of the protective layer 14 is folded back from the upper surface 13F (the surface opposite the substrate 12) of the colored layer 13 to the back surface 12F (the other surface of the substrate 12) of the substrate 12, so that the terminal portion 13E of the colored layer 13 and the terminal portion 12E of the substrate 12 are covered with the outer peripheral end 14D of the protective layer. Thereafter, the protective layer 14 and the colored layer 13 are cooled, and the resin molded body 10 including the substrate 12, the colored layer 13, and the protective layer 14 is completed.

[0044] Next, the effects of this embodiment will be described. In this embodiment, the base material 12 and the colored layer 13 can be protected by the waterproof protective layer 14. The terminal portion 13E of the colored layer 13 and the terminal portion 12E of the base material 12 are covered by the outer peripheral end portion 14D of the protective layer 14, so that the terminal processing of the resin molded body 10 can be performed without using a dedicated cover member. In addition, by providing the colored layer 13 and having the protective layer 14 be translucent, the pattern on the surface of the base material 12 containing fibers can be colored and shown as a design, and the designability can be further improved.

[0045] As shown in the comparative example of FIG. 9 and FIG. 10, in the method of forming the resin molded body 6 by molding the laminate 5 formed by laminating the base material 12, the colored layer 13, and the protective layer 14 with the molding dies 51, 52, the outer peripheral end of the laminate 5 is cut by shearing with the molding dies 51, 52, so that the cut surface needs to be terminal-treated. For this reason, as shown in FIG. 11, it is necessary to attach a cover member 7 to the terminal portion 6A of the resin molded body 6, and it is necessary to cover the terminal portion 6B of the resin molded body 6 with another member 8. In this embodiment, since the terminal can be treated using the protective layer 14, there is no need to use a cover member. In addition, since there is no need to cover the terminal portion of the resin molded body with another member, the degree of freedom of design is not restricted.

[0046] The protective layer 14 includes a waterproof layer 14A that has waterproof properties and covers the surface of the colored layer 13 opposite to the substrate 12, and an adhesive layer 14B that is interposed between the waterproof layer 14A and the colored layer 13 and bonds the waterproof layer 14A and the colored layer 13. In the welding process, the protective layer 14 is heated to a temperature that is equal to or lower than the melting point of the waterproof layer 14A and equal to or higher than the melting point of the adhesive layer 14B. In the welding process, the waterproof layer 14A can be welded to the colored layer 13 via the adhesive layer 14B. In addition, since the waterproof layer 14A is heated at a temperature equal to or lower than the melting point, it is possible to prevent the waterproof layer 14A from melting and deforming.

[0047] The melting point of the colored layer 13 is lower than that of the substrate 12, and in the welding process, the colored layer 13 is heated to a temperature equal to or lower than the melting point of the substrate 12 and equal to or higher than the melting point of the colored layer 13. In the welding process, by heating the colored layer 13 to a temperature equal to or higher than the melting point, the protective layer 14 and the colored layer 13 can be more reliably welded together. In addition, since the substrate 12 is heated to a temperature equal to or lower than the melting point, the substrate 12 can be prevented from melting. This can prevent the substrate 12 from deforming or the odor inside the substrate 12 from leaking to the outside.

[0048] <Other embodiments> The technology disclosed in this specification is not limited to the embodiments described above and illustrated in the drawings, and for example, the following embodiments are also included within the technical scope. (1) In the above embodiment, the vacuum forming and the pressure forming are performed simultaneously in the welding step. However, the protective layer may be formed by at least one of the vacuum forming and the pressure forming. (2) The shape of the resin molded body 10 is not limited to that exemplified in the above embodiment and may be modified as appropriate. In addition, the use of the resin molded body 10 is not limited to use in a vehicle and may be modified as appropriate. (3) The entire terminal portions 12E, 13E of the base material 12 and the colored layer 13 do not have to be covered by the outer peripheral end portion 14D. In other words, the terminal portions of the base material 12 and the colored layer 13 only need to be covered by at least a portion of the outer peripheral end portion 14D. (4) In the above embodiment, the hot pressing step is performed by using a double belt press device to hot press the base material 12, but the present invention is not limited to this. For example, the base material 12 may be hot pressed by using a pair of press dies. (5) In the above embodiment, the fibers in the fibrous web 17A are bonded by entangling them with each other, but the present invention is not limited to this. The fibers in the fibrous web 17A may be bonded with an adhesive, or the thermoplastic resin fibers in the fibrous web 17A may be heated to melt them and then cooled and solidified to bond the fibers. [Explanation of symbols]

[0049] 10... resin molded body, 11... laminate, 11A... outer periphery, 12... substrate, 12E... end portion of substrate, 13E... end portion of colored layer, 13... colored layer, 14... protective layer, 14D... outer periphery end portion of protective layer

Claims

1. a molding process for forming a laminate into a predetermined product shape by cutting an outer periphery of the laminate obtained by laminating a substrate containing fibers and a thermoplastic resin and a colored layer that covers one surface of the substrate and imparts color to light passing therethrough; a welding step, which is performed after the molding step, of heat-welding a protective layer having translucency and waterproofness to a surface of the colored layer opposite to the base material, In the welding process, the protective layer is adhered to the surface of the colored layer opposite the substrate by at least one of vacuum forming and pressure forming, and at least a portion of the outer circumferential end of the protective layer is folded back from the surface of the colored layer opposite the substrate to the other surface of the substrate, so that a terminal portion of the colored layer and a terminal portion of the substrate are covered by at least a portion of the outer circumferential end of the protective layer.

2. The protective layer includes a waterproof layer that has waterproof properties and covers the surface of the colored layer opposite to the base material, and an adhesive layer that is interposed between the waterproof layer and the colored layer and bonds the waterproof layer and the colored layer, The method for producing a resin molded article according to claim 1 , wherein in the welding step, the protective layer is heated to a temperature equal to or lower than a melting point of the waterproof layer and equal to or higher than a melting point of the adhesive layer.

3. The melting point of the colored layer is lower than the melting point of the base material, The method for producing a resin molded article according to claim 1 or 2, wherein in the welding step, the colored layer is heated to a temperature equal to or lower than a melting point of the base material and equal to or higher than a melting point of the colored layer.

4. A substrate including fibers and a thermoplastic resin and having a plate shape; a colored layer that imparts color to light passing through the base material and covers one surface of the base material; a protective layer having translucency and waterproofness and covering a surface of the colored layer opposite to the substrate, A resin molded body, wherein at least a portion of the outer peripheral end of the protective layer is folded back from the side of the colored layer opposite the substrate to the other side of the substrate, thereby covering the terminal portion of the colored layer and the terminal portion of the substrate.

Images