Board member and method of manufacturing the board member

Abstract

To provide a board member suitably designed to utilize the natural material texture of plant fibers, and a method for producing a board member.SOLUTION: A board member 10 includes a substrate 11 including bonded plant fibers 111, and a skin layer 12 that covers the surface of the substrate 11. The skin layer 12 includes a first layer 21, a second layer 22 and a third layer 23 in this order from the substrate 11 side. The first layer 21 has a white color. The third layer 23 has a chromatic color. The skin layer 12 has optical transparency.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a board member and a method for manufacturing a board member, and more particularly to a board member using plant fibers and a method for manufacturing a board member. [Background technology]

[0002] Known board members have a structure in which plant fibers are bound together with a thermoplastic resin (binder resin), achieving high rigidity and light weight. As described in Patent Document 1, such board members typically include a board base material containing plant fibers and a skin material, and the skin material covers one side of the board base material, thereby providing a design through the skin material. Furthermore, Patent Document 2 describes that a wood grain design is imparted to a natural wood-look decorative fiber reinforced cement board as a board member by printing with an inkjet printer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-83742 [Patent Document 2] Japanese Patent Application Publication No. 2018-52761 Summary of the Invention [Problem to be solved by the invention]

[0004] For board components made from plant fibers, consideration is being given to creating new designs that capture the unique texture of the natural material that the plant fibers possess, and adding decorative features to them. However, because they are natural materials, plant fibers vary greatly in color, and this color variation can sometimes detract from the aesthetic appearance of the board components. Therefore, painting or coloring the board components in any color was considered. However, problems arose with painting, such as the texture of the plant fiber being lost by being covered with paint, and manufacturing becoming very complicated and resulting in a rise in costs. It was found that coloring did not sufficiently suppress the color variation of the plant fiber, and instead resulted in uneven color. Furthermore, in order to add a design to board components using the texture of plant fibers, it is necessary to expose the plant fibers on the surface of the board component, but in this case, it was found that the plant fibers will discolor or fade due to ultraviolet rays, etc., and this needs to be prevented.

[0005] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a board member and a method for manufacturing a board member that can suitably impart a design that utilizes the texture of plant fibers. [Means for solving the problem]

[0006] That is, the present invention is as follows. [1] The board member of the present invention comprises a substrate formed by bonding plant fibers, A board member comprising a skin covering the surface of the base material, The skin includes a first layer, a second layer, and a third layer in this order from the substrate side, the first layer is colored whitish, the third layer is colored chromatically; The skin has optical transparency. [2] In the board member of the present invention, the second layer may be colorless and transparent. [3] In the board member of the present invention, the first layer and the third layer are formed using polyolefin, The second layer may be made of polyamide. [4] In the board member of the present invention, the third layer may be colored with a pigment. [5] The method for manufacturing a board member of the present invention comprises: a substrate formed by bonding plant fibers; a skin covering the surface of the base material; A method for manufacturing a board member in which the surface skin is light-transmitting, a heat-pressing step of heating and pressing one surface of the raw skin to be the skin and one surface of the raw substrate to be the substrate in contact with each other, the original skin comprises a first layer, a second layer, and a third layer in this order from the one surface side of the original skin, The first layer is colored white, The main point is that the third layer is colored in a chromatic color. [6] In the method for manufacturing a board member of the present invention, the second layer may be colorless and transparent. [7] In the method for manufacturing a board member of the present invention, the first layer and the third layer are formed using polyolefin, The second layer may be made of polyamide. [8] In the method for manufacturing a board member of the present invention, the third layer may be colored with a pigment. [Effects of the Invention]

[0007] According to the board member and the method for manufacturing a board member of the present invention, it is possible to suitably impart a design based on the texture of plant fibers. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a cross-sectional view illustrating a board member. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention will be described below with reference to the drawings. The matters shown here are for illustrative purposes and are intended to exemplify embodiments of the present invention, and are set forth in order to provide what is believed to be the most effective and easily understandable explanation of the principles and conceptual features of the present invention. In this regard, it is not intended to show structural details of the present invention beyond the extent necessary for a fundamental understanding of the present invention, and the description, taken together with the drawings, will make clear to those skilled in the art how some aspects of the present invention can be actually embodied.

[0010] [1] Board material The board member 10 of the present invention comprises a base material 11 formed by bonding plant fibers 111 and a skin 12 covering the surface of the base material 11. The skin 12 is provided with a first layer 21, a second layer 22, and a third layer 23 in this order from the substrate 11 side, The first layer 21 is colored whitish, The third layer 23 is colored in a chromatic color, The skin 12 is characterized by being optically transparent (see FIG. 1).

[0011] The board member 10 is not particularly limited in its use, but examples thereof include interior materials for vehicles, and is particularly useful as interior materials for vehicles having a design that can be seen from inside the vehicle. Such vehicle interior materials include door trims, instrument panels, package trays, pillar garnishes, switch bases, quarter panels, armrests, seats, seat backboards, ceiling materials, console boxes, dashboards, deck trims, etc. The board member 10 may be used for only one of these materials, or for two or more materials.

[0012] (1) Base material The base material 11 is a layer formed by binding together plant fibers 111. More specifically, the base material 11 can be a layer containing plant fibers 111 and a binder resin 112 that binds the plant fibers 111 together. The thickness, basis weight, etc. of the substrate 11 are not particularly limited and can be set appropriately depending on the use of the board member 10, the desired rigidity, etc. The thickness of the substrate 11 can be, for example, 0.5 mm or more, preferably 0.5 mm or more and 200 mm or less, more preferably 1.0 mm or more and 80 mm or less, and even more preferably 1.5 mm or more and 40 mm or less. The basis weight of the substrate 11 is, for example, 0.1 kg / m 2 It can be more than 0.2 kg / m 2 More than 3kg / m 2 The following is preferable, 400 to 2500 g / m 2 More preferably, 600 to 1800 g / m 2 is more preferred.

[0013] The plant fiber 111 is a material that provides the main structure of the base material 11 and is a fiber derived from a plant. The plant species used to obtain the plant fibers 111 are not particularly limited, and examples include kenaf, jute, Manila hemp, sisal, gampi, mitsumata, kozo, banana, pineapple, coconut, corn, sugarcane, bagasse, palm, papyrus, reed, esparto, sabaigrass, wheat, rice, bamboo, conifers (such as cedar and cypress), broadleaf trees, and cotton. These plant species may be used alone or in combination of two or more. Among these plant species, kenaf and / or jute are preferred. Kenaf is a plant with a woody stem that belongs to the Malvaceae family. Its scientific names include hibiscus cannabinus and hibiscus sabdariffa, and its common names include red hemp, Cuban kenaf, Western hemp, Thai kenaf, Mesta, Bimli, Ambari hemp, and Bombay hemp. Jute also includes jute (Corchorus capsularis L.), and plants of the hemp and tilia families, including tunaso, tunaso, and mulukhiyah.

[0014] The part of the plant body used to obtain the plant fiber is not particularly limited, and any of the woody parts, non-woody parts, leaves, stems, roots, etc. can be used. Furthermore, the plant fiber may be a fiber obtained only from a specific part, or a mixed fiber obtained by mixing fibers obtained from multiple different parts. Fibers obtained from plants may be used as plant fibers in their unprocessed form, or may be subjected to various processes before being converted into plant fibers. Examples of such processes include retting (including retting using microorganisms and retting using enzymes), boiling, steaming, heating, drying, cutting, beating, washing, and chemical treatment. These processes may be used alone or in combination of two or more.

[0015] The fiber length and fiber diameter of the plant fibers 111 are not particularly limited, but the ratio of the fiber length to the fiber diameter can be set to 10 to 15,000, for example. The fiber length can be preferably 10 mm or more, more preferably 10 mm or more and 150 mm or less, even more preferably 20 mm or more and 100 mm or less, and particularly preferably 30 mm or more and 80 mm or less. The fiber diameter can be preferably 1 mm or less, more preferably 0.01 mm or more and 1 mm or less, even more preferably 0.02 mm or more and 0.7 mm or less, and particularly preferably 0.03 mm or more and 0.5 mm or less.

[0016] When the fiber length and fiber diameter are within the above-mentioned ranges, the resulting substrate 11 (board member 10) can have high strength (bending strength, bending modulus, etc., the same applies below). It is not prohibited for the plant fibers to include those whose fiber length and fiber diameter are outside the above-mentioned ranges, but the content thereof is preferably 10% by mass, and more preferably 3% by mass or less, of the total plant fibers, assuming the total plant fibers to be 100% by mass. Furthermore, the fiber length and fiber diameter of the plant fibers 111 are usually not substantially changed during the manufacturing process. Therefore, the plant fibers 111 contained in the base material 11 of the board member 10 and the plant fibers contained in the web or laminated web that becomes the base material 11 have substantially the same fiber length and fiber diameter.

[0017] The above-mentioned fiber length means the average fiber length (hereinafter the same), and is the average value measured for a total of 200 single fibers taken at random using the direct method in accordance with JIS L1015, and the fiber length measured on a measuring scale. The above-mentioned fiber diameter means the average fiber diameter (hereinafter the same), and is the average value of 200 fibers in total, each of which is randomly selected and the fiber diameter at the center of the fiber length is measured using an optical microscope.

[0018] The proportion of plant fibers 111 contained in the base material 11 is not particularly limited, but when the total of the plant fibers 111 and the binder resin 112 is 100% by mass, it is preferably 30% by mass or more and 95% by mass or less, more preferably 32% by mass or more and 85% by mass or less, even more preferably 33% by mass or more and 75% by mass or less, and particularly preferably 35% by mass or more and 70% by mass or less. Furthermore, when the entire base material 11 is taken as 100% by mass, the proportion of the plant fibers 111 and binder resin 112 contained in the base material 11, in total, of the plant fibers 111 and the binder resin 112 is preferably 70% by mass or more, more preferably 80% by mass or more and 100% by mass or less, and even more preferably 90% by mass or more and 100% by mass or less.

[0019] The base material 11 may contain other reinforcing fibers in addition to the plant fibers 111. Examples of other reinforcing fibers include metal fibers, carbon fibers, glass fibers, and resin fibers (resin fibers made of resins other than the binder resins described below, such as polyamide resin fibers and polyester resin fibers). These may be used alone or in combination of two or more. When other reinforcing fibers are included, the proportion of the other reinforcing fibers is typically 50% by mass or less, preferably 10% by mass or less, and more preferably 5% by mass or less, with the total of the plant fibers 111 and the other reinforcing fibers being 100% by mass.

[0020] The binder resin 112 is a resin that binds the plant fibers 111 together. The type of resin in the binder resin 112 is not particularly limited, and it may contain only unmodified polyolefin resin, or may contain unmodified polyolefin resin and acid-modified polyolefin resin. When the binder resin 112 contains acid-modified polyolefin resin, the binding strength of the plant fibers 111 can be improved, and the mechanical properties of the resulting board member 10 can be improved. The binder resin 112 preferably contains only a thermoplastic resin such as an unmodified polyolefin resin or an acid-modified polyolefin resin, but may also contain a thermosetting resin in addition to the thermoplastic resin. If a thermosetting resin is contained, it is preferable that the amount of the thermosetting resin is 20% by mass or less of the entire binder resin 112, where the entire binder resin 112 is 100% by mass.

[0021] The acid-modified polyolefin contained in the binder resin 112 is a resin in which an acid-modified group is introduced into a polyolefin (olefin resin) that is a skeleton resin. The presence or absence of other modifying groups other than the acid-modified group is not important. The acid-modified polyolefin may be used alone or in combination of two or more types. The polyolefin skeleton resin includes homopolymers of one type of olefin and copolymers (binary copolymers, terpolymers, etc.) of two or more types of olefin. Examples of olefin monomers constituting polyolefin include ethylene, propylene, 1-butene, 3-methyl-1-butene, 1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, etc. These may be used alone or in combination of two or more.

[0022] For example, polypropylenes that use propylene as the olefin monomer include propylene homopolymers, propylene-ethylene copolymers, and propylene-1-butene copolymers. These may be used alone or in combination. Polypropylene usually has more than 50% of its total structural units derived from propylene monomers. Polyethylenes that use ethylene as the olefin monomer include ethylene homopolymers, ethylene-propylene copolymers, ethylene-1-butene copolymers, ethylene-1-hexene copolymers, and ethylene-4-methyl-1-pentene copolymers. These may be used alone or in combination. Polyethylene usually has 50% or more of its total structural units derived from ethylene monomers. These various olefin resins such as polypropylene and polyethylene may be used alone or in combination of two or more.

[0023] The type of acid-modified group possessed by the acid-modified polyolefin is not limited, and examples thereof include a carboxylic anhydride group (-CO-O-OC-) and a carboxylic acid group (-COOH), etc. These may be used alone or in combination of two or more. Furthermore, the acid-modified group may be introduced using any compound, such as maleic anhydride, itaconic anhydride, succinic anhydride, glutaric anhydride, adipic anhydride, maleic acid, itaconic acid, fumaric acid, acrylic acid, or methacrylic acid. These may be used alone or in combination of two or more. Among these, maleic anhydride and itaconic anhydride are preferred, with maleic anhydride being particularly preferred.

[0024] The molecular weight of the acid-modified polyolefin is not limited, and for example, the weight average molecular weight (measured by GPC method) can be 10,000 or more and 200,000 or less, preferably 15,000 or more and 100,000 or less, more preferably 20,000 or more and 60,000 or less, and even more preferably 25,000 or more and 45,000 or less. The acid value (according to JIS K0070) can be 2 or more (usually 120 or less), and is preferably 10-80, more preferably 15-70, even more preferably 20-60, and particularly preferably 23-30.

[0025] On the other hand, the non-acid-modified polyolefin contained in the binder resin 112 is a polyolefin that has not been acid-modified. There are no limitations on whether the non-acid-modified polyolefin is modified or not, and it may be an unmodified polyolefin, a modified polyolefin modified with a modifying group other than an acid-modified group, or a mixture thereof. Of the above, the description of the backbone resin constituting the acid-modified polyolefin can be applied to the unmodified polyolefin. That is, examples of unmodified polyolefins include homopolyolefins (homopolypropylene, homopolyethylene, etc.) and olefin copolymers (block polyolefins, etc.). Further, examples of olefin copolymers include propylene-ethylene copolymers (block polypropylenes) and ethylene-propylene copolymers. These may be used alone or in combination of two or more.

[0026] In addition, examples of non-acid-modified polyolefins modified with a modifying group other than an acid-modified group include acrylic modification (modification with an acryloyl group), epoxy modification (modification with an epoxy group), etc. These may be used alone or in combination of two or more. The molecular weight of the non-acid-modified polyolefin contained in the binder resin 112 is not limited, and for example, the weight average molecular weight (measured by GPC method) can be 10,000 or more and 200,000 or less, preferably 15,000 or more and 100,000 or less, more preferably 20,000 or more and 60,000 or less, and even more preferably 25,000 or more and 45,000 or less.

[0027] The ratio of acid-modified polyolefin to non-acid-modified polyolefin contained in binder resin 112 is not limited, and when the total of acid-modified polyolefin and non-acid-modified polyolefin is 100% by mass, the ratio of acid-modified polyolefin is preferably 50% by mass or less (usually 0.1% by mass or more), more preferably 0.5% by mass or more and 40% by mass or less, even more preferably 1% by mass or more and 30% by mass or less, particularly preferably 2% by mass or more and 20% by mass or less, and especially preferably 3% by mass or more and 10% by mass or less. The binder resin 112 may contain other thermoplastic resins other than polyolefins, but when the entire binder resin 112 is taken as 100% by mass, it is preferable that the proportion of other thermoplastic resins other than polyolefins is 10% by mass or less (if contained, for example, 0.01% by mass or more).

[0028] (2) Epidermis The skin 12 is a layer that covers the surface of the base material 11. Specifically, by covering the surface of the base material 11, the skin 12 can protect the base material 11 (especially the plant fibers 111 contained in the base material 11) from moisture, ultraviolet rays, and the like. Furthermore, by coloring the surface of the coated base material 11, the skin 12 can impart a design based on the texture of the plant fibers 111 contained in the base material 11, specifically, the texture, pattern, color, etc. produced by the plant fibers 111, to the board member 10, thereby improving its appearance. More specifically, the improvement in appearance due to the skin 12 is due to the fact that the plant fibers 111, which are natural materials, vary widely from one to another, particularly in terms of color, and this color variation causes uneven coloring in the board member 10, impairing the appearance. The skin 12 can suppress the color variation of the plant fibers 111 due to coloring, and can also adjust the color tone of the plant fibers 111, and by performing these functions, the appearance can be improved.

[0029] The skin 12 has three layers: a first layer 21, a second layer 22, and a third layer 23. By having these first layer 21, second layer 22, and third layer 23, the skin 12 can protect the base material 11 from moisture, ultraviolet rays, and the like, and further has the function of suppressing color variations in the plant fibers 111 and the function of adjusting the color tone of the plant fibers 111, thereby improving the aesthetic appearance. The skin 12 is arranged on the surface of the substrate 11 in the order of the first layer 21, the second layer 22, and the third layer 23 from the substrate 11 side. By having the first layer 21, the second layer 22, and the third layer 23 arranged in this manner, the skin 12 can suitably exhibit the above-mentioned functions, etc.

[0030] (2-1) 1st layer The first layer 21 is formed using a first resin. The first resin is not particularly limited, but may be a resin that has good adhesiveness to the base material 11, particularly to the binder resin 112 used in the base material 11, and specific examples include polyolefins such as polypropylene and polyethylene. The first layer 21 is colored in a whitish color and can serve as a base layer for coloring the surface 12 that colors the board member 10.

[0031] The method for coloring the first layer 21 whitish is not particularly limited, but examples include using the original color (milky white) of the first resin as is, or adding a white pigment such as titanium oxide, zinc oxide, lithopone, or white lead to the first resin. Usually, the first layer 21 can be colored whitish by adding a white pigment to the first resin. Of the three attributes of color, hue indicates differences in color tone (e.g., "red," "blue," "yellow," "green," etc.), saturation indicates differences in color vividness, and lightness indicates differences in color brightness, white is a color that has almost no hue or saturation, but does have lightness.

[0032] The white color includes white (pure white), as well as, for example, ivory, cream, off-white, light gray, and beige. Specifically, the white color can be defined as a color having a brightness (V) of 7.0 or more and 10 or less, a saturation (C) of 3 or less, and no particular limitation on the hue (H) as defined in JIS Z8721-1993. For white, the lightness (V) is preferably 7.5 or more and 10 or less, more preferably 8.0 or more and 10 or less, and even more preferably 8.5 or more and 10 or less. Furthermore, for white, the chroma (C) is preferably 2 or less, more preferably 1 or less, and even more preferably 0 (N; neutral).

[0033] The first layer 21 is colored whitish, and the plant fibers 111 contained in the base material 11 have a color darker than white (a chromatic color having hue, saturation, and brightness, usually flaxen) in comparison with the first layer 21. Therefore, the color of the plant fibers 111 contained in the base material 11 can be seen from the outside through the first layer 21. When the color of the plant fibers 111 can be seen from the outside through the first layer 21, the visible color allows the outer shape of the plant fibers 111 to be grasped and seen from the outside. That is, the first layer 21 colored whitish can have transparency to the plant fibers 111 that are darker in color than white.

[0034] The lightness of the color of the plant fibers 111 that passes through the first layer 21 and is visible from the outside is affected by the whitish color of the first layer 21. Specifically, the color of the plant fibers 111 that passes through the first layer 21 and is visible from the outside is blurred by the whitish color of the first layer 21, thereby reducing color variation due to differences in individual lightness. In other words, by being colored whitish, the first layer 21 can have the function of reducing color variation of the plant fibers 111. Furthermore, the first layer 21 has a whitish color, which allows it to have excellent reflectivity against light, including ultraviolet light, and therefore can impart light resistance to the skin 12 (board member 10), which inhibits discoloration and fading of the plant fibers 111 due to ultraviolet light and the like.

[0035] The first layer 21 can usually be formed from a resin film, a resin sheet, or the like obtained by using the first resin as a material. The thickness of the first layer 21 is not particularly limited, but can be 5 μm or more and 200 μm or less. The thickness can be preferably 10 μm or more and 150 μm or less, more preferably 15 μm or more and 80 μm or less, and even more preferably 20 μm or more and 60 μm or less. When the thickness is within the above range, the first layer 21 can have suitable permeability to the plant fibers 111. The above-mentioned thickness means an average thickness (hereinafter the same), and is, for example, an average value when the thickness is measured at multiple points on the resin film or resin sheet that forms the first layer 21 or the like.

[0036] (2-2) Second layer The second layer 22 is formed using a second resin. The second layer 22 can be a base layer that supports the first layer 21 and the third layer 23 in the skin 12 that covers the board member 10. The second resin is not particularly limited, but is preferably a resin with a higher melting point than the first resin used in the first layer 21, and more preferably a resin with good adhesiveness to the first layer 21 and the third layer 23. Specific examples of the second resin include polyamide, polyester such as polyethylene terephthalate, etc. Among these, polyamide has excellent water absorption and can impart waterproofing to the second layer 22 to prevent deterioration of the plant fibers 111 due to moisture absorption, etc.

[0037] The second layer 22, together with the first layer 21 and the third layer 23, constitutes the skin 12 and has optical transparency. The method for imparting optical transparency to the second layer 22 is not particularly limited, and examples thereof include coloring the second layer 22 in a white color similar to the first layer 21, or making the second layer 22 transparent or translucent. Typically, the second layer 22 is made transparent or semi-transparent to be light-transmitting. In this case, the plant fibers 111 can be easily seen from the outside of the skin 12 (board member 10) through the transparent or semi-transparent second layer 22. When the second layer 22 is transparent or translucent, there are no particular restrictions on its color, and it can be either colorless or colored, but among these, colorless can minimize the impact on the color of the plant fiber 111.

[0038] The second layer 22 can usually be formed from a resin film, a resin sheet, or the like obtained by using the second resin as a material. The thickness of the second layer 22 is not particularly limited, but can be 5 μm or more and 50 μm or less, preferably 7 μm or more and 40 μm or less, and more preferably 10 μm or more and 30 μm or less. When the thickness of the second layer 22 is within the above range, the skin 12 can have suitable flexibility and adequate conformability to the surface shape of the base material 11.

[0039] (2-3)Third layer The third layer 23 is formed using a third resin. The third resin is not particularly limited, but a resin that has good adhesion to the second layer 22 can be used, and specific examples include polyolefins such as polypropylene and polyethylene, which have the same resin content as the first resin. The third layer 23 is colored in a chromatic color. This third layer 23 can be used as a coloring layer for coloring the surface 12 that colors the board member 10.

[0040] The method for coloring the third layer 23 a chromatic color is not particularly limited, but examples include using a colored resin as the third resin, using a pigment, etc. Typically, the third layer 23 can be colored a chromatic color by using a pigment. A chromatic color is a color that has all three attributes of color: hue, which indicates a difference in color tone; saturation, which indicates a difference in vividness of color; and lightness, which indicates a difference in brightness of color.

[0041] Chromatic colors include brown, yellow, red, blue, green, etc. Specifically, a chromatic color can be defined as a color whose lightness (V) as defined in JIS Z8721-1993 is equal to or greater than 2.0 and less than 9.0, whose saturation (C) is greater than 2 and less than 14, and whose hue (H) is any color selected from the color wheel.

[0042] The third layer 23 has optical transparency as a component of the skin 12 together with the first layer 21 and the second layer 22. There are no particular limitations on the method for imparting optical transparency to the third layer 23, but typically, the third layer 23 is imparted optical transparency by being made transparent or translucent.

[0043] The third layer 23 can be colored to a chromatic color, so that it exhibits a color corresponding to the chromatic color. The colored third layer 23 can exhibit the color in a favorable manner in combination with the whitish color of the first layer 21. The color of the plant fibers 111 that passes through the colored third layer 23 and is visible from the outside is affected by the color of the third layer 23. Specifically, the color of the plant fibers 111 that passes through the third layer 23 and is visible from the outside is modulated by the color of the third layer 23, and color variation due to individual colors is reduced. That is, by being colored in a chromatic color, the third layer 23 can modulate the color of the plant fiber 111 and can have the function of adjusting the color tone of the plant fiber 111.

[0044] Regarding the color modulation of the plant fiber 111 by the chromatic color applied to the third layer 23, the modulation can affect at least one of the saturation and hue of the color of the plant fiber 111. When modulating the saturation of the color of the plant fiber 111, the chromatic color applied to the third resin is preferably a color close to the color of the plant fiber 111, i.e., a color similar to the color of the plant fiber 111. Similar colors can harmonize the individual colors of the plant fiber 111, which have color variations, and create a sense of color unity. When the color of the plant fiber 111 is flaxen, examples of similar colors include brown and orange. When modulating the hue of the plant fiber 111, the chromatic color applied to the third resin is preferably a color that is opposite the color of the plant fiber 111 on the color wheel, i.e., a complementary color to the color of the plant fiber 111. Complementary colors have a synergistic effect of complementing the individual colors of the plant fiber 111, and can harmonize the individual colors of the plant fiber 111, which may have color variations (this is also called "complementary color harmony"), thereby creating a sense of color unity. If the color of the plant fiber 111 is flaxen, examples of complementary colors include light blue and grayish purple.

[0045] The third layer 23 can usually be formed from a resin film, a resin sheet, or the like obtained by using the third resin as a material. The thickness of the third layer 23 is not particularly limited, but may be 5 μm or more and 200 μm or less, preferably 10 μm or more and 150 μm or less, more preferably 15 μm or more and 80 μm or less, and even more preferably 20 μm or more and 60 μm or less. When the thickness is within the above range, the first layer 21 can have suitable permeability to the plant fibers 111.

[0046] (2-4) Light transparency The skin 12 having the above-mentioned first layer 21, second layer 22 and third layer 23 is optically transparent. In the board member 10, the surface skin 12 is optically transparent, so that the plant fibers 111 of the base material 11 can be seen through the surface skin 12 from the outside. In this way, the plant fibers 111 can be seen from the outside, and therefore the board member 10 can be given a new design that incorporates the unique texture of the natural material that the plant fibers 111 have. The skin 12 can be made light-transmitting by laminating, for example, a transparent second layer 22 and a transparent third layer 23 on a white first layer 21.

[0047] The light transmittance can be defined by the total light transmittance measured in accordance with JIS K7361 for the skin 12 including the first layer 21, the second layer 22, and the third layer 23. Specifically, the total light transmittance can be 20% or more, preferably 30% or more and 95% or less, and more preferably 40% or more and 90% or less. When the total light transmittance is within the above-mentioned range, the plant fibers 111 of the substrate 11 can be clearly seen through the skin 12.

[0048] [2] Manufacturing method for board components The method for manufacturing a board member of the present invention comprises: A substrate 11 formed by bonding plant fibers 111; a skin 12 that covers the surface of the substrate 11; A method for manufacturing a board member 10 having a surface 12 that is optically transparent, comprising: a heat-pressing step of heating and pressing one surface of the raw skin to be the skin 12 and one surface of the raw substrate to be the substrate 11 in contact with each other, The raw skin comprises a first layer 21, a second layer 22, and a third layer 23 in this order from the one surface side of the raw skin, The first layer 21 is made of a first resin colored in a white or other achromatic color, The second layer 22 is made of a second resin having a higher melting point than the first resin, The third layer 23 is characterized by being made of a third resin that is colored in a chromatic color.

[0049] The raw substrate that becomes the base material 11 can be manufactured by blending resin fibers that become the binder resin 112 with plant fibers to obtain a mat, and then molding the mat into a plate using a hot press. The original skin can be produced by laminating a plurality of resin films that will become the first layer 21, the second layer 22, and the third layer 23, and bonding them together by heat fusion or the like.

[0050] The heat-pressing step is carried out by applying heat and pressure to one surface of the raw skin, specifically the surface on the first layer 21 side, in contact with one surface of the raw substrate that will become the surface of the substrate 11. The heating temperature in the heat-pressing step can be set to a temperature lower than the melting point of the second resin used in the second layer 22 and higher than the melting point of the first resin used in the first layer 21. This causes the first resin to melt, bonding the original substrate and the original skin. Specifically, when the first resin is polypropylene (melting point: 160°C-170°C) and the second resin is polyamide (melting point: 176°C-265°C), the heating temperature can be, for example, 170°C-220°C.

[0051] The pressure in the heat pressing step is not particularly limited and can be set appropriately depending on the desired thickness of the board member 10 . The board member 10 is manufactured by bonding the base material and the original skin to a desired thickness through a heat-pressing process. In this heat-pressing process, the skin 12 of the board member 10 can be formed simply by bonding the base material to the original skin, which is easier than forming a skin through multiple painting processes. The heat pressing step can be carried out using a mold, in which case the board member 10 can be formed into a desired shape according to the mold. [Explanation of symbols]

[0052] 10; board member, 11; base material, 111; plant fiber, 112; binder resin, 12; epidermis, 21; 1st layer, 22; 2nd layer, 23; 3rd layer.

Claims

1. A substrate formed by binding plant fibers; A board member comprising a skin covering the surface of the base material, The skin includes a first layer, a second layer, and a third layer in this order from the substrate side, the first layer is colored whitish, the third layer is colored chromatically; The skin is optically transparent, The board member is characterized in that the plant fibers are obtained from one or more kinds selected from kenaf, jute, Manila hemp, sisal, gampi, mitsumata, kozo, banana, pineapple, coconut, corn, sugarcane, bagasse, palm, papyrus, reed, esparto, sabaigrass, wheat, rice, bamboo, coniferous trees, broad-leaved trees, and cotton.

2. 2. The board member according to claim 1, wherein the second layer is colorless and transparent.

3. the first layer and the third layer are formed using polyolefin; 2. The board member according to claim 1, wherein the second layer is formed using polyamide.

4. 2. The board member according to claim 1, wherein the third layer is colored with a pigment.

5. A substrate formed by binding plant fibers; a skin covering the surface of the base material; A method for manufacturing a board member in which the surface skin is light-transmitting, a heat-pressing step of heating and pressing one surface of the raw skin to be the skin and one surface of the raw substrate to be the substrate in contact with each other, the original skin comprises a first layer, a second layer, and a third layer in this order from the one surface side of the original skin, The first layer is colored white, The third layer is colored in a chromatic color, The method for manufacturing a board member is characterized in that the plant fibers are obtained from one or more types selected from the group consisting of kenaf, jute, Manila hemp, sisal, gampi, mitsumata, kozo, banana, pineapple, coconut, corn, sugarcane, bagasse, palm, papyrus, reed, esparto, sabaigrass, wheat, rice, bamboo, conifers, broad-leaved trees, and cotton.

6. 6. The method for manufacturing a board member according to claim 5, wherein the second layer is colorless and transparent.

7. the first layer and the third layer are formed using polyolefin; The method for manufacturing a board member according to claim 5, wherein the second layer is made of polyamide.

8. The method for manufacturing a board member according to claim 5, wherein the third layer is colored with a pigment.

Images