Method for manufacturing board member and interior material for vehicle

Abstract

To provide a method for manufacturing a board member that contains plant fibers and has a colored layer, and that has excellent design even when holes penetrating through the board in the thickness direction are provided, and to provide an interior material for a vehicle that has excellent design. [Solution] A method for manufacturing a board member (20) having a colored layer (22) on one side of a plate-shaped base material (21) containing plant fibers and thermoplastic resin, and having a hole (24) penetrating in the thickness direction of the board, includes a lamination process for forming a laminated preboard (20L) in which the colored layer (22) is laminated on one side of a preboard (21P) containing plant fibers and thermoplastic resin; a thin-walled portion forming process for forming a thin-walled portion (28) with a relatively thin plate thickness in the part of the laminated preboard (20L) where the hole (24) will be formed; and a hole forming process for penetrating the thin-walled portion (28) in the thickness direction of the base material (21) to form the hole (24).

Description

[Technical Field]

[0001] The technologies disclosed herein relate to methods for manufacturing board members and interior materials for vehicles. [Background technology]

[0002] A conventional board member using plant fibers is known from Patent Document 1. Patent Document 1 describes a multi-layered board member in which a waterproof layer for suppressing the release of volatile organic compounds from the board substrate and a surface material such as synthetic leather, genuine leather, or fabric are laminated in this order on one side of a board substrate containing plant fibers. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-83742 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, board components have come to utilize the texture and feel of the board substrate itself, which contains plant fibers, as a design element, and in such cases, a translucent layer is used as a waterproof layer, rather than using a skin material such as synthetic leather, genuine leather, or fabric. Furthermore, in order to color the board substrate in a desired color while preserving its texture and feel, a translucent colored layer, such as a spunbond, may be provided between the board substrate and the waterproof layer.

[0005] Furthermore, when a board member containing vegetable fibers and not having a skin material is used as an interior material for a vehicle, for example, the design may be enhanced by providing a thin-walled portion in part of the board member, which allows light irradiated from outside the vehicle compartment to pass through the thin-walled portion.

[0006] However, when a board member has a colored layer as described above, the color variations in the colored layer become noticeable due to transmitted light, which detracts from the appearance. To address this issue, it is conceivable to provide holes penetrating the board surface instead of the thin-walled portions, but board members containing plant fibers tend to have rough cut surfaces, and when the inner surfaces of the holes are brightly illuminated by light, the surface roughness becomes noticeable, resulting in a problem of reduced design quality.

[0007] The technology disclosed in this specification was completed based on the above circumstances, and aims to provide a method for manufacturing a board member that contains plant fibers and has a colored layer, and a vehicle interior material that has excellent design, even when holes that penetrate through the board in the thickness direction are provided. [Means for solving the problem]

[0008] The technology disclosed in this specification, which was completed to solve the above-mentioned problems, is a method for manufacturing a board member having a colored layer on one side of a plate-shaped substrate containing plant fibers and thermoplastic resin, and having a hole formed therethrough in the thickness direction of the substrate, and includes: a lamination process for forming a laminated preboard in which the colored layer is laminated on one side of the preboard containing the plant fibers and the thermoplastic resin; a thin-walled portion forming process for forming a thin-walled portion with a relatively thin plate thickness in the part of the laminated preboard where the hole will be formed; and a hole forming process for penetrating the thin-walled portion in the thickness direction of the substrate to form the hole.

[0009] According to the above manufacturing method, since the holes are formed in the relatively thin portions of the board member, the area of ​​the inner peripheral surface of the holes is smaller than when the holes are formed in portions other than the thin portions, and the surface roughness and colored layer on the inner peripheral surface of the holes are less noticeable, thereby making it possible to provide a board member with excellent design.

[0010] Between the lamination step and the thin-walled portion formation step, a protrusion formation step may be included in the portion of the laminated pre-board that forms the hole, wherein the colored layer side is recessed and the opposite side of the colored layer protrudes, and in the thin-walled portion formation step, the tip of the protrusion may be cut in a direction along the surface of the base material to form the thin-walled portion in which the thickness of the tip is relatively reduced.

[0011] According to the above manufacturing method, the holes are positioned recessed from the surface of the board member on which the colored layer is applied. As a result, the inner surface of the holes is less visible when viewing the board member from the colored layer side, thus improving the aesthetic appeal. Furthermore, since the tips of the protrusions are ultimately positioned along the surface of the base material, when attaching functional components such as lighting devices to the base material (board member) on the side of the base material opposite to the colored layer, the mounting stability of the functional components to the base material (board member) can be maintained.

[0012] In the lamination process, the colored layer and the waterproof layer are laminated sequentially on one side of the pre-board, and in the thin-walled portion forming process, the tip of the protruding portion may be cut to a position where the base material and the colored layer are cut away, leaving the waterproof layer intact.

[0013] According to the above manufacturing method, the cross-section of the colored layer exposed during the thin-walled section formation process and the hole formation process faces the opposite side of the substrate from the colored layer. Therefore, when viewing the hole from the colored layer side, the cross-section of the colored layer is not visible on the inner circumference of the hole. This prevents the appearance of the hole from being diminished due to the prominence of the colored layer's cross-section. Furthermore, in the hole formation process, the plant fibers are not penetrated through the substrate, but rather through the waterproof layer. This prevents the inner surface of the hole from becoming rough due to the plant fibers.

[0014] After the lamination process, the following steps may be performed simultaneously by heat press molding: a protrusion formation step in which a protrusion is formed in the portion of the laminated pre-board that forms the hole, such that the colored layer side is recessed and the opposite side of the colored layer protrudes; and a thin-walled portion formation step in which the plate thickness at the tip of the protrusion is made relatively thinner.

[0015] In the above manufacturing method, the hole is recessed from the surface of the board member on which the colored layer is provided, so that the inner circumferential surface of the hole is difficult to see when the board member is viewed from the colored layer side, thereby further improving the design. In addition, the thin-walled portion forming process can be performed simultaneously with the protrusion forming process, which simplifies the manufacturing process.

[0016] Another technology disclosed in this specification, which was completed to solve the above-mentioned problems, is a vehicle interior material comprising a board member having a hole penetrating in the thickness direction of the board, and a lighting device provided on the exterior surface of the vehicle cabin of the hole in the board member, wherein the board member has a plate-shaped base material containing plant fiber and thermoplastic resin, and a colored layer laminated on the interior surface of the base material, and the depth dimension of the inner surface of the hole is smaller than the thickness dimension of the board member.

[0017] According to the above configuration, the depth of the inner peripheral surface of the hole is smaller than the thickness of the board member, so the surface roughness and colored layer on the inner peripheral surface of the hole are less noticeable compared to when the depth of the inner peripheral surface of the hole is the same as the thickness of the board member, resulting in excellent design properties.

[0018] The hole may be provided at the tip of a protruding portion of the board member where the side with the colored layer is recessed and the side opposite the colored layer protrudes.

[0019] According to the above configuration, when viewing the interior material (board member) for the vehicle from the inside of the vehicle (colored layer side), the inner surface of the hole becomes less visible, thus improving the aesthetic appeal.

[0020] Furthermore, a cross section of the colored layer may be exposed on the outer periphery of the hole on the outer surface of the vehicle cabin of the base material. With this configuration, the cross section of the colored layer is not visible on the inner periphery of the hole when the hole is viewed from the inside of the vehicle cabin (the colored layer side), and therefore, it is possible to prevent the cross section of the colored layer from being conspicuous and thereby reducing the appearance of the hole. [Effects of the Invention]

[0021] According to the technology disclosed in this specification, it is possible to provide a method for manufacturing a board member that contains plant fibers and has a colored layer, and a vehicle interior material that has excellent design properties, even when holes that penetrate through the board thickness direction are provided. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a front view of a door trim according to a first embodiment; [Figure 2] An explanatory diagram showing the lamination process [Figure 3] An explanatory diagram showing the protrusion forming process [Figure 4] Cross-sectional view of an ornament board with protrusions formed before drilling [Figure 5] An explanatory diagram showing the thin-walled portion forming process [Figure 6] An explanatory diagram showing the slit forming process (cross-sectional view of ornament board) [Figure 7] A partially enlarged perspective cross-sectional view of an ornament board with slits formed therein. [Figure 8] Enlarged cross-sectional view of a part of the door trim [Figure 9] 10A and 10B are explanatory views showing a protrusion portion forming step and a thin-walled portion forming step in the second embodiment; [Figure 10] Cross-sectional view of ornamental board with protrusions and thin-walled sections formed before drilling [Figure 11] An explanatory diagram showing the slit forming process (cross-sectional view of ornament board) [Figure 12] 10 is a cross-sectional view of an ornament board before drilling in which a protrusion according to a third embodiment is formed. [Figure 13] An explanatory diagram showing the thin-walled portion forming process [Figure 14] An explanatory diagram showing the slit forming process (cross-sectional view of ornament board) [Figure 15] FIG. 1 is a partially enlarged perspective cross-sectional view of an ornament board in which a slit is formed without forming a thin-walled portion. DETAILED DESCRIPTION OF THE INVENTION

[0023] <Embodiment 1> A first embodiment will be described with reference to Figures 1 to 8. This embodiment illustrates a method for manufacturing a door trim 10 (an example of a vehicle interior material) used in vehicle interior materials, and an ornament board 20 (an example of a board member) provided on the door trim 10. In each figure, arrows FR and RR indicate the front and rear of the vehicle, respectively, arrows UP and DW indicate the upper and lower sides of the vehicle, respectively, and arrows IN and OUT indicate the interior and exterior of the vehicle (inside the vehicle), respectively.

[0024] The door trim 10 constitutes the interior portion of a vehicle side door and is attached to the door inner panel from the inside of the vehicle. The door trim 10 is mainly composed of a trim board 11, and in addition to the trim board 11, it also includes various functional parts such as an inside handle 12, an armrest 13, a door pocket 14, a speaker grill 15, and a lighting device 30, which are provided on the trim board 11 (see Figures 1 and 8).

[0025] The trim board 11 is made up of a plurality of board members assembled together, and is mainly composed of an upper board 16, a middle board 17, a lower board 18, an ornament board 20, an armrest board 19, and the like. Of these, the ornament board 20 is the board member of this embodiment, and is disposed across the armrest 13 provided on the trim board 11 in the vertical direction. The interior surface of the ornament board 20 is not covered with a skin material such as synthetic leather, genuine leather, or fabric, but is configured to utilize the texture and feel of a base material 21 (described later) as a design element. Note that the board members other than the ornament board 20 are configured such that the surface of the plate-shaped base material 21 is covered with a skin material.

[0026] The ornament board 20 is a plate-shaped member having a predetermined thickness. As shown in Figures 7 and 8, the ornament board 20 comprises a plate-shaped base material 21, a colored layer 22 covering the interior surface (design surface side) of the base material 21, and a transparent or translucent waterproof film (an example of a waterproof layer) 23 covering the interior surface of the colored layer 22.

[0027] The base material 21 includes plant fibers and thermoplastic resin. Examples of plant fibers included in the base material 21 include bast plant fibers such as kenaf and plant fibers obtained by unraveling fibrous wood. The base material 21 is obtained by heat-press molding a fiber mat made by mixing plant fibers and thermoplastic resin fibers, and the thermoplastic resin functions as a binder that binds the plant fibers together. Examples of thermoplastic resins included in the base material 21 include polyolefin resins (polypropylene, polyethylene, etc.) and polyester resins (aliphatic polyester resins such as polylactic acid and polycaprolactone, aromatic polyester resins such as polyethylene terephthalate).

[0028] In this embodiment, the base material 21 is made of plant fibers obtained from kenaf and polypropylene, but the material of the base material 21 is not limited to these and can be changed as appropriate.

[0029] In this embodiment, a spunbond nonwoven fabric is used as the colored layer 22. The colored layer 22 is a layer for coloring the surface of the substrate 21 and is translucent. The transparent or translucent waterproof film 23 has waterproof and deodorizing properties, protects the surface of the substrate 21 including the colored layer 22, and provides a clear coating-like effect, thereby enhancing the design of the substrate 21. As an example of the waterproof film 23, a polyethylene-nylon-polyethylene three-layer film can be exemplified (each layer is not shown).

[0030] In this embodiment, the ornament board 20 has a plurality of slits (an example of holes) 24 arranged in the vertical direction, each slit extending linearly and continuously along the longitudinal direction (see FIG. 1). That is, the ornament board 20 has a plate surface extending in the substantially vertical direction, and the slits 24 open toward the interior and exterior of the vehicle in the vehicle width direction and extend in the longitudinal direction of the vehicle.

[0031] More specifically, the slits 24 are provided in a manner that penetrates the tips 27 of protrusions (an example of a protrusion) 25 of the ornament board 20 that protrude from the interior side of the vehicle cabin toward the exterior side of the vehicle cabin and extend in a rib-like manner in the front-to-rear direction (see FIGS. 7 and 8). The interior side of the protrusions 25 forms groove-like recesses 26 that are recessed from the main surface of the ornament board 20 inside the vehicle cabin. Light is irradiated from the exterior side of the vehicle cabin toward the interior side of the vehicle cabin through these slits 24 in the vehicle width direction, so that the door trim 10 (ornament board 20) is decorated with linear light. Note that the above-mentioned "approximately vertical" includes a state in which the plate surface is slightly inclined from the vertical direction.

[0032] Light is emitted from a lighting device 30 attached to the outside of the vehicle cabin of the slit 24 (see FIG. 8). The lighting device 30 is configured by housing an LED (not shown) and a long light guide capable of guiding the light emitted from the LED in a long rectangular box-shaped housing 31. At least the surface of the housing 31 facing the slit 24 is made of a light-transmitting material. The LED is connected to a power supply device such as a battery mounted on the vehicle via a control device (not shown). The housing 31, with the LED and light guide housed therein, is attached to the ornament board 20 from the outside of the vehicle cabin in a manner that makes it contact the ornament board 20.

[0033] Next, a description will be given of an example of a method for manufacturing the ornament board 20 and the door trim 10. Each step will be described in detail below.

[0034] <Lamination process> First, a laminated preboard 20L is produced by laminating a spunbond colored layer 22 and a waterproof and odor-resistant waterproof film 23 in this order on one side of a preboard 21P made of plant fibers bound with a thermoplastic resin (see FIG. 2). The waterproof film 23 can be, for example, a three-layer film of polypropylene-nylon-polypropylene.

[0035] <Protrusion forming process (an example of a protrusion forming process)> Next, the laminated preboard 20L is heated by a heater (not shown) to soften it. Thereafter, the softened laminated preboard 20L is placed between a pair of forming dies 40 (upper die 41 and lower die 42), and the upper die 41 and lower die 42 are closed to press-form the laminated preboard 20L using the forming surfaces of the upper die 41 and lower die 42 (see FIG. 3). As a result, the laminated preboard 20L takes on a shape that matches the shape of the forming space, and a pre-perforated ornament board 20F is formed before the slits 24 are formed.

[0036] At this time, elongated protrusions 25 (an example of a protrusion) are formed in the portions of the pre-perforated ornament board 20F where the slits 24 will be formed, recessed toward the colored layer 22 and protruding from the opposite surface of the colored layer 22 (see FIGS. 3 and 4). Hereinafter, the portions of the pre-perforated ornament board 20F other than the protrusions 25 that form the main body of the ornament board 20 will be referred to as the main surface 29. The cross section of the protrusions 25 protruding from the main surface 29 is generally rectangular with a wider diameter on the opening side. In other words, the tips 27 of the protrusions 25 are flat and extend parallel to the plate surface of the main surface 29.

[0037] In this embodiment, the thickness of the protrusions 25 and the main surface portions 29 is generally uniform throughout. Specifically, the thickness of the ornamental board 20F before drilling is approximately 2.3 mm throughout.

[0038] <Thin part forming process> Next, the tips 27 of the protrusions 25 are ground in a direction along the plate surface of the main surface 29 to form thin-walled portions 28 that are thinner than the other portions (see FIG. 5). At this time, it is preferable that the thickness of the thin-walled portions 28 is approximately the same as the thickness of the waterproof film 23, and it is preferable to ground the tips 27 of the protrusions 25 so that at least no colored layer 22 remains. In this embodiment, the thickness of the thin-walled portions 28 (the thickness of the waterproof film 23) is approximately 0.4 mm.

[0039] <Slit forming process (an example of a hole forming process)> Next, the entire thin-walled portion 28 is punched through in the thickness direction of the main surface portion 29 (a direction intersecting the plate surface) to form the slit 24 (see FIGS. 6 and 7). At this time, only the cross section of the waterproof film 23 is visible at the opening edge of the slit 24 when viewed from the colored layer 22 side (the upper side in FIG. 6, the design surface side), and the cross section of the colored layer 22 is arranged to face the opposite direction from the design surface (the lower side in FIG. 6). This prevents the colored layer 22 from being exposed inside the slit 24, which would otherwise spoil the appearance of the slit 24. In this embodiment, the width of the slit 24 is approximately 2.0 mm.

[0040] It is also possible to form slits 24 by directly punching out tips 27 of protrusions 25 in the thickness direction of main surface 29 from the state shown in Figure 4 without going through the thin-walled portion forming step, but in that case, the rough surface of base material 21 that was cut during penetration will be exposed on the inner periphery of slit 24, which will look unattractive (see Figure 15). In contrast, in this embodiment, by removing base material 21 arranged on tips 27 of protrusions 25 in advance in the thin-walled portion forming step, it is possible to prevent base material 21 from being exposed on the inner periphery of slit 24 when the slit forming step is subsequently carried out.

[0041] Furthermore, in order to form the slit 24, it is possible to perform polishing or the like until the slit 24 is formed at the tip 27 of the protrusion portion 25, rather than forming the thin-walled portion 28 and then punching out the main surface portion 29 in the plate thickness direction. However, punching out the thin-walled portion 28 in the plate thickness direction after forming it, as in this embodiment, allows the inner surface of the slit 24 to be finished more beautifully.

[0042] <Lighting equipment installation process> Finally, the lighting device 30 is installed along the formed slit 24 on the opposite side (outside the vehicle interior) of the colored layer 22 (see Figure 8). At this time, the outer circumference of the slit 24 on the exterior surface of the base material 21 is aligned with the surface of the ornament board 20 (main surface portion 29), so the lighting device 30 can be installed stably.

[0043] Next, the effects will be described. This embodiment is a manufacturing method for an ornament board 20 having a colored layer 22 on one side of a plate-shaped base material 21 containing plant fibers and a thermoplastic resin and having slits 24 penetrating in the board thickness direction, and includes a lamination step of forming a laminated preboard 20L by laminating the colored layer 22 and the waterproof film 23 on one side of a preboard 21P containing plant fibers and a thermoplastic resin, a thin-walled portion forming step of forming a thin-walled portion 28 with a relatively thin board thickness in a portion of the laminated preboard 20L where the slits 24 will be formed, and a slit forming step of penetrating the thin-walled portion 28 in the board thickness direction of the base material 21 (main surface portion 29) to form the slits 24.

[0044] According to the above manufacturing method, the slits 24 are formed in the relatively thin portions 28 of the ornament board 20, so the area of ​​the inner peripheral surface of the slits 24 is smaller than when the slits 24 are formed in portions other than the thin portions 28, and the surface roughness of the inner peripheral surface of the slits 24 and the colored layer 22 are less noticeable. In other words, it is possible to provide an ornament board 20 with excellent design.

[0045] In addition, between the lamination process and the thin-walled portion forming process, a protrusion portion forming process is included in which a protrusion portion 25 is formed in the portion of the laminated preboard 20L where the slit 24 is formed, the protrusion portion 25 being recessed on the colored layer 22 side and protruding on the opposite side of the colored layer 22, and in the thin-walled portion forming process, the tip 27 of the protrusion portion 25 is ground in a direction along the plate surface of the base material 21 (main surface portion 29) to form a thin-walled portion 28 with a relatively thin plate thickness at the tip 27.

[0046] According to the above manufacturing method, the slits 24 are provided at positions recessed from the surface of the ornament board 20 on which the colored layer 22 is provided, so that the inner circumferential surfaces of the slits 24 are less visible when the ornament board 20 is viewed from inside the vehicle compartment (the colored layer 22 side), further improving the design. Furthermore, because the tips 27 of the protrusions 25 are ultimately arranged in a direction along the plate surface of the base material 21 (main surface portion 29), when a functional component such as a lighting device 30 is attached to the base material 21 on the outside of the vehicle compartment (the side opposite the colored layer 22), the functional component can be attached stably to the base material 21 (ornament board 20).

[0047] Furthermore, in the lamination process, the colored layer 22 and the waterproof film 23 are sequentially laminated on one side of the pre-board 21P, and in the thin-walled section formation process, the tip 27 of the protruding section 25 is polished to the point where the base material 21 and the colored layer 22 are cut away, leaving only the waterproof film 23.

[0048] According to the above manufacturing method, the cross section of the colored layer 22 exposed in the thin-walled portion forming process and the slit forming process faces the outside of the vehicle cabin (the side opposite the colored layer 22) of the base material 21, so when the slit 24 is viewed from the inside of the vehicle cabin (the colored layer 22 side), the cross section of the colored layer 22 is not visible on the inner periphery of the slit 24, thereby preventing the cross section of the colored layer 22 from being conspicuous and degrading the appearance of the slit 24. Furthermore, in the slit forming process, the slit penetrates the waterproof film 23 rather than the base material 21 containing plant fibers, so that the inner periphery of the slit 24 is prevented from becoming rough due to the plant fibers.

[0049] Furthermore, the door trim 10 of this embodiment comprises an ornament board 20 having a slit 24 penetrating in the thickness direction, and a lighting device 30 provided on the exterior side of the slit 24 in the ornament board 20. The ornament board 20 has a colored layer 22 on the interior side of a plate-shaped base material 21 containing plant fibers and thermoplastic resin, and the depth dimension of the inner circumferential surface of the slit 24 is smaller than the thickness dimension of the ornament board 20 (main surface portion 29).

[0050] According to the above configuration, the depth dimension of the inner surface of the slit 24 is smaller than the thickness dimension of the ornament board 20 (main surface portion 29). Therefore, compared to the case where the depth dimension of the inner surface of the slit 24 is the same as the thickness dimension of the ornament board 20 (main surface portion 29), the surface roughness of the inner surface of the slit 24 and the colored layer 22 are less noticeable. In other words, it has superior design appeal.

[0051] Furthermore, the slit 24 is provided at the tip 27 of a protruding portion 25 on the ornament board 20 where the side with the colored layer 22 (inside the vehicle interior) is recessed and the opposite side of the colored layer 22 (outside the vehicle interior) protrudes. With this configuration, when viewing the door trim 10 (ornament board 20) from the inside of the vehicle interior (side with the colored layer 22), the inner surface of the slit 24 becomes less visible, further improving the aesthetic appeal.

[0052] Furthermore, the cross-section of the colored layer 22 is exposed on the outer circumference of the slit 24 on the exterior surface of the base material 21 inside the vehicle. With this configuration, when the slit 24 is viewed from the inside of the vehicle (the side with the colored layer 22), the cross-section of the colored layer 22 is not visible on the inner circumference of the slit 24, thereby preventing the appearance of the slit 24 from being degraded by the prominence of the cross-section of the colored layer 22.

[0053] Thus, according to this embodiment, even when an ornament board 20 containing plant fibers and having a colored layer 22 is provided with a slit 24 penetrating in the thickness direction of the board, it is possible to provide a method for manufacturing an ornament board 20 with excellent design and a door trim 10 with excellent design.

[0054] <Embodiment 2> Next, Embodiment 2 will be described with reference to Figures 9 to 11. This embodiment differs from Embodiment 1 in that the ridge formation process and the thin-walled section formation process are performed simultaneously. In the following, only the processes that differ from Embodiment 1 will be described, and redundant explanations of processes that are the same as in Embodiment 1 will be omitted.

[0055] <Protrusion Forming Process (an example of a protrusion forming process) and Thin-Walled Section Forming Process> After the lamination process is completed, the laminated pre-board 20L is heated by a heater (not shown) to soften it. Then, the softened laminated pre-board 20L is placed between a pair of molds 140 (upper mold 141 and lower mold 142), and the upper mold 141 and lower mold 142 are closed, thereby press-molding the laminated pre-board 20L with the respective molding surfaces of the upper mold 141 and lower mold 142 (see Figure 9). As a result, the laminated pre-board 20L takes on a shape that conforms to the shape of the molding space, and the pre-drilled ornament board 120F is formed before the slit 124 is created (see Figure 10).

[0056] In this embodiment, the thickness of the tip 127 of the protruding portion (an example of a projection) 125 formed in the part of the ornament board 120F before drilling that forms the slit 124 is made into a thin-walled portion 128 that is thinner than other parts by press molding. In other words, the distance between the mold faces of the upper mold 141 and the lower mold 142 is set to a relatively smaller distance dimension in the part where the protruding portion 125 is press molded compared to other parts (see Figure 9), and the thin-walled portion 128 is formed by the crushing of the base material 21, the colored layer 22 and the waterproof film 23. In this embodiment, the thickness of the thin-walled portion 128 is about 1.4 mm, compared to about 2.3 mm for the main surface portion 29.

[0057] Subsequently, the entire thin-walled portion 128 is punched through in the thickness direction of the main surface portion 29 by a slit forming process (an example of a hole forming process) similar to that of Embodiment 1 above, thereby forming a slit 124 (see Figure 11).

[0058] Even with this manufacturing method of the embodiment, the slit 124 is formed in the thin-walled portion 128 of the ornament board 120, which is relatively thin in thickness. Therefore, compared to the case where the slit 124 is formed in a part other than the thin-walled portion 128, the area of ​​the inner surface of the slit 124 is smaller, and the surface roughness of the inner surface of the slit 124 and the colored layer 22 are less noticeable. In other words, an ornament board 120 with superior design can be provided. Furthermore, since the slit 124 is provided in a recessed position (recess 126) of the ornament board 120 from the surface on which the colored layer 22 is provided, the inner surface of the slit 124 is less visible when viewing the ornament board 20 from the inside of the vehicle (colored layer 22 side), further improving the design. Moreover, since the thin-walled portion formation process can be performed simultaneously with the ridge formation process, the manufacturing process can be simplified.

[0059] Furthermore, as in this embodiment, when a thin-walled portion 128 is formed by compressing the laminated pre-board 20L, the density of the thin-walled portion 128 may be relatively higher, resulting in a darker color compared to other parts. However, as described above, the slit 124 is provided in a recessed position (recess 126) from the surface of the ornament board 120 on which the colored layer 22 is provided. Therefore, when viewing the ornament board 20 from the inside of the vehicle (the side with the colored layer 22), the inner surface of the slit 124 is less visible, and the darkness of the color is less noticeable.

[0060] <Other embodiments> The technologies disclosed herein are not limited to the embodiments described above in the description and drawings, but also include, for example, the following embodiments.

[0061] (1) In the above embodiment, the ornament boards 20 and 120 are shown to have slits 24 and 124, but the shape of the hole formed in the board member is not limited to a slit, and may be a round hole, for example. If a round hole is used, a bowl-shaped projection 225 can be formed instead of the ridge 25 and 125, and the tip 227 of the projection 225 can be polished to form a thin-walled portion 228, through which the round hole 224 can be passed (see Figures 12 to 14). Even when the hole is a slit, it is not limited to a straight shape, but may also be curved.

[0062] (2) In the above embodiment, a configuration was shown in which thin-walled portions 28 and 128 were formed at the tips 27 and 127 of the protruding portions 25 and 125, and then slits 24 and 124 were formed through them. However, it is also possible to form the thin-walled portions by means of compression or cutting, for example, without forming the protruding portions, and then form the holes through them. Furthermore, the compression or cutting when forming the thin-walled portions may be performed on the side of the colored layer or on the side opposite to the colored layer.

[0063] (3) In the above embodiment 1, in the thin-walled portion formation process, the tip 27 of the protruding portion 25 was polished to a position where the base material 21 and the colored layer 22 were cut away and the waterproof film 23 remained to form the thin-walled portion 28. However, a form in which the colored layer 22 and a part of the base material 21 remain in the thin-walled portion 28 is also possible.

[0064] (4) In the above embodiment, an ornament board 20 for a vehicle door trim 10 was used as an example of a board member and interior material for a vehicle. However, the technology disclosed herein is not limited to ornament boards and can be applied in various ways to other interior materials for vehicles such as pillar garnishes, ceiling materials, console boxes, dashboards, various instrument panels, deck trims, etc., as well as interior materials for vehicles such as railways, airplanes, ships, etc., and board members other than interior materials for vehicles. [Explanation of symbols]

[0065] 10: Door trim (interior material for vehicles) 11: Trim board 20, 120: Ornament board (board component) 20F, 120F: Ornament board before drilling 20L: Laminated pre-board 21: Base material 21P: Pre-board 22: Colored layer 23: Waterproof film (waterproof layer) 24, 124: Slit (hole) 25, 125: Protruding part 26, 126: Recess 27, 127: Tip 28, 128: Thin-walled part 29: Main surface part 30: Lighting device 31: Housing part 40, 140: Molding mold 41, 141: Upper mold 42, 142: Lower mold

Claims

1. A method for manufacturing a board member having a colored layer on one side of a plate-shaped substrate containing plant fibers and a thermoplastic resin, and having holes penetrating in the plate thickness direction, a lamination step of forming a laminated preboard by laminating the colored layer on one side of a preboard containing the plant fiber and the thermoplastic resin; a thin-walled portion forming step of forming a thin-walled portion by relatively thinning the board thickness in a portion of the laminated preboard where the hole is to be formed; and a hole forming step of penetrating the thin-walled portion in the thickness direction of the base material to form the hole.

2. a protrusion forming step, which is performed between the laminating step and the thin-walled portion forming step, of forming a protrusion in a portion of the laminated preboard where the hole is to be formed, the protrusion being recessed on the colored layer side and protruding from the opposite surface side of the colored layer; A method for manufacturing a board member as described in claim 1, wherein in the thin-walled portion forming process, the tip of the protrusion is cut in a direction along the plate surface of the base material to form the thin-walled portion with a relatively thin plate thickness at the tip.

3. In the lamination step, the colored layer and the waterproof layer are laminated in order on one side of the pre-board, The method for manufacturing a board member according to claim 2 , wherein in the thin-walled portion forming step, the tip of the protruding portion is cut to a position where the base material and the colored layer are cut away and the waterproof layer remains.

4. After the lamination step, a protrusion forming step of forming a protrusion in a portion of the laminated preboard where the hole is to be formed, the protrusion being recessed on the colored layer side and protruding on the opposite surface side of the colored layer; a thin-walled portion forming step of forming the thin-walled portion by relatively thinning the plate thickness of the tip of the protrusion; 2. The method for manufacturing a board member according to claim 1, wherein steps 1 and 2 are simultaneously carried out by hot press molding.

5. a board member having a hole penetrating in a thickness direction; and a lighting device provided on an exterior surface side of the hole in the board member, the board member has a plate-shaped base material containing plant fibers and a thermoplastic resin, and a colored layer laminated on the vehicle interior side of the base material, The depth dimension of the inner peripheral surface of the hole is smaller than the thickness dimension of the board member.

6. 6. The vehicle interior material according to claim 5, wherein the hole is provided at a tip of a protruding portion of the board member that is recessed on the colored layer side and protrudes on the opposite surface side of the colored layer.

7. 7. The vehicle interior material according to claim 6, wherein a cross section of the colored layer is exposed on the outer surface of the vehicle cabin of the base material at an outer periphery of the hole.

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