Board member and method for manufacturing a board member

Abstract

The present invention provides a board component and a method for manufacturing the board component that can reduce costs while using bamboo fibers and are less prone to whitening. [Solution] A board member comprising a base material made of plant fibers and thermoplastic resin, and a film layer covering one side of the base material, wherein the base material is composed of a main layer which is the main body of the base material and is made of plant fibers other than bamboo and the thermoplastic resin, and a decorative layer which is laminated on the main layer and is made of bamboo fibers and the thermoplastic resin, and the film layer covers the decorative layer.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a board member and a method for manufacturing the board member.

Background Art

[0002] Conventionally, a fiber board having a structure in which plant fibers are bonded with a thermoplastic resin has been known (for example, Patent Document 1). This type of fiber board is lightweight and has high rigidity, and is widely used as an interior material for vehicles such as a door trim of a vehicle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, there is a desire to utilize the unique texture and feel of the natural material of the fiber board containing plant fibers as a design. Among them, bamboo with a relatively thick fiber diameter as a plant fiber has been attracting attention as one of various materials. However, since bamboo fiber is more expensive than other plant fibers, there is a problem that the sales cost of the product inevitably increases. In addition, since bamboo fiber is not particularly high in strength among plant fibers, it is necessary to increase the amount used to ensure strength, which not only further increases the cost but also increases the weight.

[0005] In addition, as described above, bamboo fiber has a relatively thick fiber diameter, and there is a situation where rough unevenness is likely to occur on the surface of the fiber board. For this reason, when covering the surface of the fiber board with an increased amount of bamboo fiber with a film layer, a gap is likely to occur between the surface of the fiber board and the film layer, leading to whitening.

[0006] The technology disclosed herein has been achieved in view of the above circumstances, and aims to provide a board member and a method for manufacturing the board member that can reduce costs while using bamboo fibers and is less prone to whitening. [Means for solving the problem]

[0007] The technology disclosed herein was completed in view of the above circumstances and comprises a substrate made of plant fibers and a thermoplastic resin, and a film layer covering one side of the substrate, wherein the substrate is composed of a main layer which forms the main body of the substrate and is made of plant fibers other than bamboo and the thermoplastic resin, and a decorative layer which is laminated on the main layer and is made of bamboo fibers and the thermoplastic resin, and the film layer is a board member which covers the decorative layer.

[0008] According to the above configuration, a decorative layer containing bamboo fibers is placed on one side (the design side) of the base material of the board member, allowing for the creation of a bamboo design. On the other hand, since the main layer of the base material is made of plant fibers other than bamboo and thermoplastic resin, manufacturing costs can be reduced compared to a configuration in which expensive bamboo fibers are used throughout the entire board member.

[0009] Furthermore, although bamboo fiber is not among the strongest plant fibers, the main layer of the base material, excluding the decorative layer, is formed from plant fibers other than bamboo and thermoplastic resin, ensuring strength in the main layer. Therefore, the proportion of bamboo fiber in the decorative layer can be kept low, which in turn reduces the unevenness that occurs on one side of the base material (the surface of the decorative layer), thereby suppressing the occurrence of whitening when a film layer is applied to one side of the base material.

[0010] The proportion of bamboo fibers in the decorative layer may be smaller than the proportion of plant fibers other than bamboo in the main layer.

[0011] The main layer may consist of a first layer disposed on the opposite side of the decorative layer, containing plant fibers other than bamboo in the same proportion as the bamboo fibers contained in the decorative layer, and having the same thickness as the decorative layer, and a second layer disposed between the decorative layer and the first layer, containing plant fibers other than bamboo in a higher proportion than the bamboo fibers contained in the decorative layer.

[0012] According to the above configuration, since the proportion of plant fibers in the decorative layer and the first layer, which are arranged on the front and back of the base material, is the same, warping of the base material caused by the difference in the proportion of plant fibers on the front and back of the base material can be suppressed. Furthermore, by making the proportion of plant fibers in the second layer relatively high, it is possible to ensure strength in the second layer, thereby reducing the proportion of plant fibers in the decorative layer and the first layer and suppressing surface irregularities of the base material.

[0013] Furthermore, other technologies disclosed herein include a method for manufacturing a board member comprising a main layer made of plant fibers other than bamboo and a thermoplastic resin, and a decorative layer laminated on the main layer and made of bamboo fibers and a thermoplastic resin, wherein the decorative layer is covered with a film layer, comprising a main layer fiber web forming step of forming a main layer fiber web by laminating mixed fibers for the main layer, which are a mixture of plant fibers other than bamboo and thermoplastic resin fibers, and a decorative layer fiber web for the base material formed by laminating mixed fibers for the decorative layer, which are a mixture of bamboo fibers and thermoplastic resin fibers, on one side of the main layer fiber web. The manufacturing method involves sequentially performing the following steps: a layer fiber web lamination step; a fiber mat formation step of intertwining the base fiber webs to form a fiber mat; a pre-board formation step of heating and pressing the fiber mat to form a pre-board in which a decorative layer pre-board portion is integrally formed on one side of the main layer pre-board portion; a film placement step of placing a film on the side of the pre-board in which the decorative layer pre-board portion is arranged; and a heat press molding step of heating the pre-board on which the film is arranged and pressing it with a pair of molds to form the board member.

[0014] According to the above manufacturing method, by laminating a fiber web for a decorative layer composed of bamboo fibers in a fibrillated state and thermoplastic resin fibers on the fiber web for the main layer, it becomes difficult to form lumps of bamboo fibers in the decorative layer. Also, a configuration is formed in which a large amount of thermoplastic resin exists around the bamboo fibers, making it difficult for the bamboo fibers to be exposed on the surface of the base material. Further, since the bamboo fibers and the thermoplastic resin fibers are entangled in a mixed state to form a fiber mat, the bamboo fibers can easily penetrate into the fiber web for the main layer, and the compatibility between the main layer and the decorative layer can be improved.

Effect of the Invention

[0015] According to the technology disclosed in this specification, it is possible to provide a board member that can suppress costs while using bamboo fibers and is difficult to cause whitening, and a method for manufacturing the board member.

Brief Description of the Drawings

[0016] [Figure 1] Front view of a door trim of an embodiment [Figure 2] Partial enlarged cross-sectional view of an ornament board [Figure 3] Explanatory drawing showing the process of forming a fiber web for the main layer and the process of laminating a fiber web for the decorative layer [Figure 4] Explanatory drawing showing the process of forming a fiber mat and the process of forming a pre-board [Figure 5] Explanatory drawing showing the process of arranging a matte film [Figure 6] Explanatory drawing showing the hot press forming process [Figure 7] Table showing photographs of ornament boards of Examples and Reference Examples

Modes for Carrying Out the Invention

[0017] One embodiment will be described with reference to FIGS. 1 to 7. In this embodiment, as a board member, an ornament board 20 provided in a door trim 10 used as an interior material for a vehicle and a manufacturing method thereof will be exemplified.

[0018] The door trim 10 constitutes the interior side portion of the side door of the vehicle and is attached to the door inner panel from the interior side of the vehicle. The door trim 10 is mainly composed of a trim board 11 having a generally rectangular shape. In addition to the trim board 11, the door trim 10 includes various functional components such as an inside handle 12, an armrest 13, a door pocket 14, a speaker grill 15, etc. provided on the trim board 11 (see Fig. 1).

[0019] The trim board 11 is formed by assembling a plurality of board members to each other and is mainly composed of an upper board 17, a lower board 18, an ornament board 20, and an armrest board 19. Among these, the ornament board 20 is the board member of this embodiment, and the ornament board 20 is arranged above the armrest 13 provided on the trim board 11. The interior surface of the ornament board 20 is not covered with a skin material such as synthetic leather, genuine leather, or fabric, and is configured to utilize the texture and feel of the material of the ornament board 20 itself as a design. Note that the board members other than the ornament board 20 are configured such that the surface of a plate-like base material is covered with a skin material.

[0020] The ornament board 20 is a plate-like member having a predetermined thickness. The ornament board 20 is configured such that one side (the side arranged on the interior side of the vehicle) of a base material layer 21 containing plant fibers and a thermoplastic resin is covered with a semi-transparent matte film (an example of a film layer) 29 (see Fig. 2).<00001​​​​​​Examples of plant fibers other than bamboo included in the first layer 23 and the second layer 24 (main layer 22) include bast plant fibers such as kenaf and plant fibers obtained by unraveling fibrous wood. Examples of thermoplastic resins included in the first layer 23 and the second layer 24 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). The first layer 23 and the second layer 24 are said to have different proportions of plant fibers.

[0023] In this embodiment, both the first layer 23 and the second layer 24 are made of plant fibers (kenaf fibers 27) obtained from kenaf and polypropylene. However, the materials of the first layer 23 and the second layer 24 are not limited to these and can be changed as appropriate. Furthermore, the first layer 23 and the second layer 24 can each be made of different plant fibers or thermoplastic resins. In addition, both or one of the first layer 23 and the second layer 24 may be colored black.

[0024] The bamboo fibers 28 contained in the decorative layer 25 are fibers derived from bamboo. The bamboo fibers 28 have a larger diameter than the kenaf fibers 27 contained in the first layer 23 and the second layer 24. The thermoplastic resin contained in the decorative layer 25 is the same as the thermoplastic resin contained in the first layer 23 and the second layer 24 described above. The thermoplastic resin contained in the decorative layer 25 may be the same material as the thermoplastic resin contained in the first layer 23 and the second layer 24, or it may be a different material. The decorative layer 25 may be colored black.

[0025] In the aforementioned substrate 21, the thermoplastic resin functions as a binder that binds the plant fibers (kenaf fibers 27 and bamboo fibers 28).

[0026] In the base material 21 of this embodiment, the ratio of the thicknesses of each layer described above is 1st layer 23:2nd layer 24:decorative layer 25 = 1:3:1. In other words, the 1st layer 23 and the 2nd layer 24 constitute the main layer 22 of the base material 21. In the base material 21 of this embodiment, the plant fiber content of each layer is the same for the 1st layer 23 and the decorative layer 25, while the 2nd layer 24 has a higher plant fiber content compared to the 1st layer 23 and the decorative layer 25. Furthermore, the total plant fiber content (kenaf fiber 27) in the 1st layer 23 and the 2nd layer 24 (main layer 22) is higher than the bamboo fiber content in the decorative layer 25. Specifically, the plant fiber content is 10-20% by weight in the 1st layer 23 and the decorative layer 25, and 70-80% by weight in the 2nd layer 24.

[0027] The interior side (design side) of the decorative layer 25 is covered with a translucent matte film (an example of a film layer) 29. The matte film 29 has waterproof and odor-resistant properties, protects the surface of the decorative layer 25, and provides a matte effect, thereby enhancing the design of the ornament board 20. The matte film 29 is constructed by applying a matting agent to a nylon film.

[0028] Next, the effects of the ornament board 20 described above will be explained. The ornament board 20 of this embodiment comprises a base material 21 made of plant fibers and thermoplastic resin, and a matte film 29 covering one side of the base material 21. The base material 21 is composed of a main layer 22 which is the main body of the base material 21 and is made of plant fibers other than bamboo (kenaf fibers 27) and thermoplastic resin, and a decorative layer 25 which is laminated on the main layer 22 and is made of bamboo fibers 28 and thermoplastic resin. The matte film 29 covers the decorative layer 25.

[0029] According to the above configuration, a decorative layer 25 containing bamboo fibers 28 is placed on one side (the design side) of the base material 21 of the ornament board 20, so that a bamboo design can be expressed. On the other hand, since the main layer 22 of the base material 21 is made of plant fibers other than bamboo (kenaf fibers 27) and thermoplastic resin, the manufacturing cost can be reduced compared to a configuration in which expensive bamboo fibers 28 are used throughout the entire ornament board 20.

[0030] Furthermore, although bamboo fibers 28 are not among the strongest plant fibers, the main layer 22 of the base material 21, excluding the decorative layer 25, is formed from plant fibers other than bamboo (kenaf fibers 27) and thermoplastic resin, so strength can be ensured in the main layer 22. Consequently, the proportion of bamboo fibers 28 in the decorative layer 25 can be kept low, and in turn, the unevenness caused by bamboo fibers 28 on one side of the base material 21 (the surface of the decorative layer 25) can be reduced, thereby suppressing the occurrence of whitening when a matte film 29 is provided on one side of the base material 21.

[0031] Furthermore, the proportion of bamboo fibers 28 in the decorative layer 25 is set to be smaller than the proportion of plant fibers other than bamboo (kenaf fibers 27) in the main layer 22.

[0032] Furthermore, the main layer 22 is located on the opposite side of the decorative layer 25 and consists of a first layer 23 which contains the same proportion of plant fibers other than bamboo (kenaf fibers 27) as the proportion of bamboo fibers 28 contained in the decorative layer 25 and has the same thickness as the decorative layer 25, and a second layer 24 which is located between the decorative layer 25 and the first layer 23 and contains a higher proportion of plant fibers other than bamboo (kenaf fibers 27) than the proportion of bamboo fibers 28 contained in the decorative layer 25.

[0033] According to the above configuration, since the proportion of plant fibers (kenaf fibers 27 and bamboo fibers 28) in the decorative layer 25 and the first layer 23 arranged on the front and back of the base material 21 are equal, warping of the base material 21 caused by the difference in the proportion of plant fibers on the front and back of the base material 21 can be suppressed. Furthermore, by making the proportion of plant fibers (kenaf fibers 27) in the second layer 24 relatively high, it is possible to ensure strength in the second layer 24, thereby reducing the proportion of plant fibers in the decorative layer 25 and the first layer 23 and suppressing surface irregularities of the base material 21 caused by the bamboo fibers 28.

[0034] Next, the manufacturing method of the ornament board 20 of this embodiment will be described. However, the manufacturing method of this ornament board 20 is not limited in any way to the following embodiments.

[0035] The manufacturing method for the ornament board 20 of this embodiment involves sequentially performing the following steps: a fiber web formation step for the main layer, a fiber web lamination step for the decorative layer, a fiber mat formation step, a pre-board formation step, a matte film placement step, and a heat press molding step. Each step will be described in detail below.

[0036] <Process for forming the main layer fiber web> First, plant fibers (kenaf fibers 27) and thermoplastic resin fibers (polypropylene fibers) for forming the first layer 23 are laminated in layers from the base material 21 to form the first layer fiber web 23W, which will serve as the base for the first layer 23. The first layer fiber web 23W is manufactured using a fiber mat manufacturing apparatus 30 (see Figures 3 and 4).

[0037] The fiber mat manufacturing apparatus 30 is equipped with three sets of fiber supply units 31, a feed conveyor 32, a fiber opening cylinder 33, a conveyor 34, and a suction device 35. Downstream of these, it is equipped with a entanglement device 36 and a cutter 37. In Figure 3, only the first of the three sets of components is shown in detail, and overlapping components are only partially shown, with the overlapping parts omitted.

[0038] The mixed fibers 23S that constitute the first layer 23 described above are fed into the first fiber supply unit 31. Specifically, the mixed fibers 23S of plant fibers (kenaf fibers 27) and thermoplastic resin fibers (polypropylene fibers) mixed in a predetermined ratio are fed into the first fiber supply unit 31 and supplied to the fiber opening cylinder 33 by the feed conveyor 32. The fiber opening cylinder 33 has a cylindrical cylinder body 33A with a plurality of protrusions 33B on its surface (outer surface) and rotates clockwise in Figure 3 around the central axis L1. The rotating fiber opening cylinder 33 is capable of opening the mixed fibers 23S sent from the feed conveyor 32 by scratching them with the protrusions 33B. Furthermore, as the fiber opening cylinder 33 rotates, the mixed fibers 23S are caught on the surface (protrusions 33B) of the fiber opening cylinder 33 and transported upward, and then released into the air by the centrifugal force caused by the rotation of the fiber opening cylinder 33. In Figure 3, the direction of rotation of the fiber-opening cylinder 33 is indicated by arrow A1.

[0039] A walker roller 38 and a stripper roller 39 are provided on the outer circumference of the fiber-opening cylinder 33, and multiple protrusions are formed on each of their surfaces. The walker roller 38 has the function of opening the mixed fibers 23S by passing them between itself and the fiber-opening cylinder 33, and the stripper roller 39 has the function of peeling off the mixed fibers 23S that have adhered to the surface of the walker roller 38.

[0040] The conveyor 34 is a mesh conveyor with a mesh-like structure, and it is possible to deposit the mixed fibers 23S on its upper surface. A suction device 35 is located below the conveyor 34, and by sucking in air, the mixed fibers 23S can be drawn onto the upper surface of the conveyor 34. The conveyor 34 forms the first layer fiber web 23W by transporting the layer of mixed fibers 23S to the right side of Figure 3 while depositing the mixed fibers 23S on its upper surface. The direction of transport of the mixed fibers 23S by the conveyor 34 is indicated by arrow A2.

[0041] As described above, the first layer fiber web 23W is transported below a second fiber supply unit (not shown). The second fiber supply unit receives the mixed fibers 24S that constitute the second layer 24, i.e., a mixture of plant fibers (kenaf fibers 27) and thermoplastic resin fibers (polypropylene fibers) mixed in a predetermined ratio. The other components are the same as those of the first unit described above, and by depositing the mixed fibers 24S on the upper surface of the first layer fiber web 23W, a main layer fiber web 22W is formed in which the second layer fiber web 24W is laminated on the first layer fiber web 23W.

[0042] <Lamination process for decorative fiber webs> Similarly, the main layer fiber web 22W formed as described above is transported below a third fiber supply unit (not shown). The third fiber supply unit receives the mixed fibers 25S that constitute the decorative layer 25 described above, that is, mixed fibers 25S of bamboo fibers 28 and thermoplastic resin fibers (polypropylene fibers) mixed in a predetermined ratio. The other components are the same as those of the first unit described above, and by depositing the mixed fibers 25S on the upper surface of the main layer fiber web 22W (the upper surface of the second layer fiber web 24W), a base fiber web 21W is formed in which the decorative layer fiber web 25W is laminated on the main layer fiber web 22W.

[0043] <Fiber mat formation process> The fiber web 21W for the base material described above is entangled with each other by the entanglement device 36 to form a fiber mat 21M that will form the base material 21 (see Figure 4). At this time, the boundary between the fiber web 23W for the first layer and the fiber web 24W for the second layer, and the boundary between the fiber web 24W for the second layer and the fiber web 25W for the decorative layer are in an intertwined state. The fiber mat 21M is then transported to the heating and pressurizing device 40.

[0044] <Pre-board formation process> The heating and pressing device 40 consists of, for example, a hot plate press or a hot belt press, and is equipped with a heating means such as a heater that generates heat when electricity is applied. The fiber mat 21M described above is heated or pressed after heating. The heating temperature at this time is set to be above the temperature at which the thermoplastic resin fibers contained in the fiber mat 21M melt.

[0045] As a result, the thermoplastic resin fibers contained in the fiber mat 21M melt, and a pre-board 21P is formed in which the kenaf fibers 27 and bamboo fibers 28 are bound together by the thermoplastic resin. The pre-board 21P is made up of a main layer side pre-board portion 22P to which the kenaf fibers 27 are bound by the thermoplastic resin, and a decorative layer side pre-board portion 25P to which the bamboo fibers 28 are bound by the thermoplastic resin. Note that the pre-board 21P is in a state before it is molded into the product shape (ornament board 20) of the interior material for vehicles.

[0046] Furthermore, by heating and pressing the fiber mat 21M in this manner, the boundary between the layer containing kenaf fibers 27 (main layer side pre-board section 22P) and the layer containing bamboo fibers 28 (decorative layer side pre-board section 25P) mixes together, resulting in a state where each layer blends seamlessly with the others.

[0047] <Matte film placement process and heat press molding process> Next, the pre-board 21P is heat-press molded into the desired shape. First, the pre-board 21P formed in the pre-board forming process described above is heated and set between the upper mold 51 and the lower mold 52 of the molding die 50, which are in the open state (see Figure 5). At this time, the matte film 29 is placed between the upper surface of the pre-board 21P (the surface on which the decorative layer side pre-board portion 25P is placed) and the molding surface 51A of the upper mold 51. Once the matte film 29 is in the predetermined position, the upper mold 51 and the lower mold 52 are closed, and the pre-board 21P and the matte film 29 are cooled and compressed (see Figure 6).

[0048] The upper mold 51 is a movable mold that can be moved relative to the lower mold 52 (fixed mold) by a drive device (e.g., electric motor, air cylinder, hydraulic cylinder, etc.) not shown. The upper mold 51 and lower mold 52 can be closed and opened by moving the upper mold 51 closer to and further away from the lower mold 52.

[0049] The lower mold 52 has a molding surface 52A that protrudes toward the upper mold 51, which is the surface facing the upper mold 51. The upper mold 51 has a molding surface 51A that is recessed, corresponding to the shape of the lower mold 52, which is the surface facing the lower mold 52.

[0050] As shown in Figure 6, when the upper mold 51 and lower mold 52 are closed, the upper mold 51 is positioned opposite the lower mold 52 at a distance equal to the thickness of the ornament board 20. In other words, in the closed state, a molding space S1 for molding the ornament board 20 is formed between the upper mold 51 and the lower mold 52.

[0051] As a result, when the pre-board 21P and matte film 29 are pressed by the upper die 51 and lower die 52, the pre-board 21P and matte film 29 are compressed into a shape corresponding to the shape of the molding space S1, and the ornament board 20 is formed. The thickness of the ornament board 20 is set to be less than the sum of the thickness of the pre-board 21P and the thickness of the matte film 29.

[0052] When the thermoplastic resin contained in the pre-board 21P cools and solidifies, the thermoplastic resin seeping out from the pre-board 21P adheres the matte film 29 to the upper surface of the pre-board 21P, thereby obtaining an ornament board 20 with the matte film 29 attached.

[0053] Subsequently, the upper mold 51 and the lower mold 52 are opened, and the ornament board 20 is demolded. This completes the manufacturing of the ornament board 20.

[0054] Next, the effects of the manufacturing method for the ornament board 20 of this embodiment will be described. This embodiment is a manufacturing method for an ornament board 20 in which the decorative layer 25 of a base material 21 is covered with a matte film 29, the base material 21 comprising a main layer 22 made of plant fibers other than bamboo (kenaf fibers 27) and thermoplastic resin, and a decorative layer 25 laminated on the main layer 22 and made of bamboo fibers 28 and thermoplastic resin, the manufacturing method comprising a main layer fiber web forming step of forming a main layer fiber web 22W by laminating a main layer mixed fiber 22S made of a mixture of plant fibers other than bamboo (kenaf fibers 27) and thermoplastic resin fibers, and forming a base material fiber web 21W by laminating a decorative layer mixed fiber 25S made of a mixture of bamboo fibers 28 and thermoplastic resin fibers on one side of the main layer fiber web 22W. This manufacturing method sequentially performs the following steps: a fiber web lamination step for the decorative layer; a fiber mat formation step to form a fiber mat 21M by intertwining a fiber web 21W for the base material; a preboard formation step to form a preboard 21P in which the decorative layer preboard portion 25P is integrally formed on one side of the main layer preboard portion 22P by heating and pressing the fiber mat 21M; a matte film placement step to place a matte film 29 on the side of the preboard 21P in which the decorative layer preboard portion 25P is located; and a heating press molding step to form an ornament board 20 by heating the preboard 21P in which the matte film 29 is placed and pressing it with a pair of molds 50.

[0055] According to the above manufacturing method, by laminating a decorative layer fiber web 25W, which consists of opened bamboo fibers 28 and thermoplastic resin fibers, onto the main layer fiber web 22W, clumps of bamboo fibers 28 are less likely to form in the decorative layer 25. In addition, a large amount of thermoplastic resin is present around the bamboo fibers 28, making it less likely for the bamboo fibers 28 to be exposed on the surface of the base material 21. In other words, it is less likely for irregularities caused by the bamboo fibers 28 to form on the surface of the base material 21. Furthermore, since the bamboo fibers 28 and thermoplastic resin fibers are intertwined in a mixed state to form a fiber mat 21M, the bamboo fibers 28 can easily penetrate into the main layer fiber web 22W, improving the compatibility between the main layer 22 and the decorative layer 25.

[0056] <Examples> Using the manufacturing method described above, the following two types of ornament boards 20 were produced.

[0057] (Example 1) Ornament boards were prepared with the following proportions of plant fiber / thermoplastic resin in each layer and their respective basis weights.

[0058] Decorative layer: Bamboo fiber / PP = 10 / 90 300g / m 3 Layer 2: Kenaf fiber / PP = 80 / 20 900g / m 3 Layer 1: Kenaf fiber / PP=10 / 90 300g / m 3 The thickness ratio of each layer was set as follows: Layer 1: Layer 2: Decorative Layer = 1:3:1.

[0059] (Example 2) Using the same manufacturing method described above, ornament boards were produced with the following plant fiber / thermoplastic resin content ratios and basis weights in each layer.

[0060] Decorative layer: Bamboo fiber / PP = 20 / 80 300g / m 3 Second layer: Kenaf fiber / PP=70 / 30 900g / m 3 Layer 1: Kenaf fiber / PP = 20 / 80 300g / m 3 The thickness ratio of each layer was set to 1st layer:2nd layer:decorative layer = 1:3:1, as in Example 1.

[0061] (Reference example 1) A substrate was prepared in which the plant fiber / thermoplastic resin content ratio was the same as in Example 1 above, and which did not have a matte film.

[0062] (Reference example 2) A substrate was prepared in which the plant fiber / thermoplastic resin content ratio was the same as in Example 2 above, and which did not have a matte film.

[0063] Figure 7 is a table summarizing photographs of the ornament boards from Example 1 and Example 2 described above, as well as, for reference, the example of Example 1 without the matte film (i.e., the base material of Example 1) and the example of Example 2 without the matte film (i.e., the base material of Example 2).

[0064] These photographs confirm that bamboo fibers can be incorporated as a design element in any of the ornament boards. Furthermore, it was confirmed that whitening was less likely to occur even when these substrates were covered with a matte film (Examples 1 and 2). In addition, no warping occurred in any of the cases.

[0065] <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.

[0066] (1) In the above embodiment, the base material 21 was shown to have a three-layer structure consisting of a first layer 23, a second layer 24, and a decorative layer 25. However, the base material may also have a two-layer structure consisting of a layer made of plant fibers other than bamboo and thermoplastic resin, and a layer made of bamboo fibers and thermoplastic resin.

[0067] (2) In the above embodiment, a translucent matte film 29 was given as an example of a film layer, but the type of film layer is not limited to the above embodiment.

[0068] (3) The proportion of plant fibers in each layer of the base material is not limited to the above embodiment. Also, the ratio of the thicknesses of each layer is not limited to the above embodiment and can be changed as appropriate.

[0069] (4) In the above embodiment, an ornament board 20 constituting a door trim 10 for a vehicle was given as an example of a board member, but the technology disclosed herein is not limited to the ornament board 20 and can be applied in various ways to other vehicle interior materials such as pillar garnish, ceiling material, console box, dashboard, various instrument panels, deck trim, etc., as well as to vehicle interior materials for railways, airplanes, ships, etc., and for applications other than vehicle interior materials. [Explanation of Symbols]

[0070] 20: Ornament board (board component) 21: Base material 21M: Fiber mat 21P: Pre-board 21W: Fiber web for base material 22: Main layer 22P: Pre-board section on the main layer side 22W: Fiber web for the main layer 23: First layer 23S, 24S: Mixed fiber (mixed fiber for the main layer) 23W: Fiber web for the first layer (fiber web for the main layer) 24: Second layer 24W: Fiber web for the second layer (fiber web for the main layer) 25: Decorative layer 25P: Pre-board section on the decorative layer side 25S: Mixed fiber for the decorative layer 25W: Fiber web for the decorative layer 27: Kenaf fiber (plant fiber other than bamboo) 28: Bamboo fiber 29: Matte film (film layer) 30: Fiber mat manufacturing equipment 40: Heating and pressurizing equipment 50: Molding die

Claims

1. The device comprises a base material made of plant fibers and thermoplastic resin, and a film layer covering one side of the base material. The aforementioned substrate is The main component of the substrate is a main layer made of plant fibers other than bamboo and the thermoplastic resin, The main layer is laminated with a decorative layer made of bamboo fibers and the thermoplastic resin, and the main layer is composed of these layers. The aforementioned film layer is a board member covering the aforementioned decorative layer.

2. The board member according to claim 1, wherein the proportion of bamboo fibers in the decorative layer is smaller than the proportion of plant fibers other than bamboo in the main layer.

3. The aforementioned main layer is A first layer is provided on the opposite side of the decorative layer, containing plant fibers other than bamboo in the same proportion as the bamboo fibers contained in the decorative layer, and having the same thickness as the decorative layer. The board member according to claim 1 or claim 2, comprising: a second layer disposed between the decorative layer and the first layer, and containing a higher proportion of plant fibers other than bamboo than the proportion of bamboo fibers contained in the decorative layer.

4. A method for manufacturing a board member comprising a base material having a main layer made of plant fibers other than bamboo and a thermoplastic resin, and a decorative layer laminated on the main layer and made of bamboo fibers and a thermoplastic resin, wherein the decorative layer is covered with a film layer, A main layer fiber web forming step, in which a main layer fiber web is formed by laminating a main layer mixed fiber obtained by mixing plant fibers other than bamboo and thermoplastic resin fibers, A decorative layer fiber web lamination step is performed to form a base fiber web by laminating a mixed fiber for the decorative layer, which is a mixture of bamboo fibers and thermoplastic resin fibers, onto one side of the main layer fiber web. A fiber mat forming step involves intertwining the fiber web for the base material to form a fiber mat, A pre-board forming step involves heating and pressing the aforementioned fiber mat to form a pre-board in which the decorative layer pre-board portion is integrally formed on one side of the main layer pre-board portion, A film placement step involves placing the film on the side of the pre-board where the decorative layer side pre-board portion is located. A method for manufacturing a board member, comprising: a heating press molding step in which the pre-board on which the film is arranged is heated and pressed with a pair of molds to form the board member; and so on.

Images