Moisture-proof decorative paper, and moisture-proof decorative panels and fittings using the same

Abstract

To provide moisture-proof decorative paper which is used in an indoor door, a kitchen door, a storage door and fusuma, a moisture-proof decorative plate using the same, and a fitting such as a door, and specifically, ones having a function of preventing warpage generated by humidity change and temperature change.SOLUTION: Decorative paper 20 is formed by laminating a paper base material 21, a printed pattern layer 22 and a protective resin layer 23 in this order, where the moisture-proof layer has a layer 31 containing a polyvinyl alcohol-based resin, a vapor-deposited layer 32, and a layer 33 containing polyolefin having at least one selected from a carboxyl group, a salt of a carboxyl group, a carboxylic acid anhydride group and carboxylate, in this order, on the back face side of the paper base material. The thickness of the layer 31 containing the polyvinyl alcohol-based resin may be 1 μm or more and 5 μm or less, the thickness of the vapor-deposited layer 32 may be 30 nm or more and 100 nm or less, and the thickness of the layer 33 containing the polyolefin may be 2 μm or more and 10 μm or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to moisture-proof decorative paper and moisture-proof decorative panels and doors that use the same, and is used for fittings such as interior doors, kitchen doors, storage doors, and sliding doors. More specifically, the paper has the function of preventing warping caused by changes in humidity, temperature, etc. [Background technology]

[0002] In the past, interior doors, kitchen doors, storage doors, and other fixtures would gradually warp during use due to humidity and temperature differences. This phenomenon occurs mainly because humidity and temperature differences between the indoor and outdoor interiors cause an imbalance in the moisture content distribution inside the wooden fixture. In other words, when humidity differences occur, differences occur in the amount of moisture absorbed and released on the front and back surfaces of the wooden fixture, causing the higher humidity side to expand due to a higher moisture content and the lower humidity side to shrink due to a lower moisture content, resulting in warping. Furthermore, when a temperature difference occurs, moisture in the wood substrate moves to the cold side, creating a gradient in moisture content along the thickness direction and causing warping. Usually, the cold side has high humidity and moisture content, and in this case, the two effects work in the same direction, which is thought to be the most pronounced cause of warping.

[0003] Methods of preventing such warping of wooden fixtures include using sheets of the same material on the front and back of doors and other fixtures to prevent them from warping to one side, and using metal supports for the frames of the fixtures. Furthermore, a method of reducing the amount of moisture absorbed and released by building materials by using moisture-proof sheets with low moisture permeability as building materials is widely used.

[0004] It has been proposed to previously adhere a moisture-proof decorative sheet having a five-layer structure of, from the front side, a protective resin layer / printed pattern layer / reinforced paper between the sheets / synthetic resin layer / reinforced paper between the sheets, to the front side of a board substrate such as plywood, using an adhesive, and also adhere a moisture-proof back sheet having a three-layer structure of reinforcing paper between the sheets / synthetic resin / reinforced paper between the sheets, using an adhesive, to the back side of the board substrate to form a moisture-proof decorative board, and then adhere this moisture-proof decorative board to the front and back of a flush door, respectively, using an adhesive (see paragraphs

[0013] to

[0016] and Figures 1 to 4 of Patent Document 1). The moisture permeability of the moisture-proof sheet at this time is 5 to 30 (g / m 2 24 hours) is considered to be good (see [Claim 2] of Patent Document 1). According to this configuration, in the moisture-proof decorative board used as the front and back decorative surface material of a flush door, the moisture-proof sheet and moisture-proof back sheet attached to the front and back of the board base material have high moisture-proof functionality, so changes in the moisture content of the board base material of the moisture-proof decorative board due to temperature and humidity differences between the front and back sides of the flush door are suppressed, resulting in an anti-warping effect. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 3206408 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in recent years, from the perspective of door design, doors over 2m in height are increasingly being adopted. As doors become taller, even a slight amount of warping can cause a large amount of warping in the entire door, so higher moisture resistance is required. As a sheet with high moisture resistance, a moisture-proof sheet with a synthetic resin base material, a metal vapor deposition film and a coating layer, has been proposed. The moisture permeability is 5 (g / m 2 It is said to be highly effective in preventing warping when used for a period of 24 hours or less.

[0007] All of these moisture-proof sheets use plastic materials, so reducing the amount of plastic used is desirable from an environmental perspective. Furthermore, when recycling decorative panels, doors, and other fixtures to which these moisture-proof sheets are attached, the wood base material and the plastic portion (synthetic resin layer and synthetic resin base material) must be separated, making them unsuitable for recycling.

[0008] The present invention has been made to solve this problem, and aims to provide a moisture-proof decorative paper that prevents warping even when used in a place where there is a large difference in temperature and humidity environment on both sides, and a moisture-proof decorative board and fittings such as doors that use the same. Furthermore, the present invention aims to provide moisture-proof decorative paper that reduces the amount of plastic used and has excellent recyclability, and moisture-proof decorative boards and fittings such as doors that use the same. [Means for solving the problem]

[0009] The present invention has solved this problem, and one aspect of the moisture-proof decorative paper of the present invention is a moisture-proof decorative paper having a moisture-proof layer laminated on the back surface of the decorative paper, wherein the decorative paper is formed by laminating a paper base material, a printed pattern layer, and a protective resin layer in this order, and the moisture-proof layer is characterized by having, on the back surface side of the paper base material, a layer containing a polyvinyl alcohol-based resin, a vapor-deposited layer, and a layer containing a polyolefin having at least one selected from a carboxyl group, a salt of a carboxyl group, a carboxylic anhydride group, and a carboxylic acid ester, in this order.

[0010] Furthermore, the moisture-proof decorative paper according to one aspect of the present invention is characterized in that the thickness of the layer containing the polyvinyl alcohol resin is 1 μm or more and 5 μm or less.

[0011] The moisture-proof decorative paper according to one aspect of the present invention is characterized in that the thickness of the vapor-deposited layer is 30 nm or more and 100 nm or less.

[0012] The moisture-proof decorative paper according to one aspect of the present invention is characterized in that the thickness of the polyolefin-containing layer is 2 μm or more and 10 μm or less.

[0013] The moisture-proof decorative paper according to one aspect of the present invention is characterized in that the weight of the paper substrate is 50% by mass or more based on the entire moisture-proof layer.

[0014] The moisture-proof decorative paper according to one aspect of the present invention is characterized in that an adhesive primer layer is provided on the outer surface of the moisture-proof layer.

[0015] The moisture-proof decorative paper according to one aspect of the present invention is characterized in that the paper base material is a reinforced inter-paper paper.

[0016] The moisture-proof decorative board according to one embodiment of the present invention is a board substrate such as plywood with a moisture-proof decorative paper attached to one side thereof, and has a moisture permeability of 5 g / m 2 A moisture-proof sheet on the backside with a durability of 24 hours or less is attached to the other side of the board substrate.

[0017] The back moisture-proof sheet of the moisture-proof decorative board in one embodiment of the present invention is formed by laminating a moisture-proof layer on the back surface of a paper substrate, and the moisture-proof layer is characterized by comprising, on the back surface side of the paper substrate, a layer containing a polyvinyl alcohol-based resin, a vapor-deposited layer, and a layer containing a polyolefin having at least one selected from a carboxyl group, a salt of a carboxyl group, a carboxylic anhydride group, and a carboxylic acid ester, in this order.

[0018] A fitting such as a door according to one aspect of the present invention is characterized in that moisture-proof decorative panels are pressure-bonded to the front and back surfaces of a wooden core member with the back moisture-proof sheet side facing inward. [Effects of the Invention]

[0019] According to one aspect of the present invention, moisture-proof decorative paper can significantly reduce moisture permeability, and can prevent warping of fittings such as doors even when used in a location where there is a large difference in temperature and humidity environment on both sides. Furthermore, the moisture-proof decorative paper according to one aspect of the present invention can contribute to reducing the amount of plastic materials used. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is an explanatory diagram showing the cross-sectional shape of one embodiment of the moisture-proof decorative paper of the present invention. FIG. [Figure 2] 1. FIG. 4 is an explanatory diagram showing a modified example of the moisture-proof decorative paper of FIG. 1, illustrating the cross-sectional shape of one embodiment of the back moisture-proof sheet A. [Figure 3] 1 is an explanatory diagram showing the cross-sectional shape of one embodiment of a moisture-proof decorative board A of the present invention. [Figure 4] 4 is an explanatory diagram showing a cross-sectional shape of an example of a moisture-proof decorative board B, which is a modification of the moisture-proof decorative board A shown in FIG. 3. FIG. [Figure 5] 1 is an explanatory diagram showing the cross-sectional shape of one embodiment of a door or other fixture using a moisture-proof decorative door panel A of the present invention. [Figure 6] 6 is an explanatory diagram showing a modified example of the door or other fitting shown in FIG. 5, illustrating the cross-sectional shape of one embodiment of the door or other fitting using the moisture-proof decorative board B. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, embodiments of the present invention will be described with reference to FIGS. The drawings are schematic, and the relationship between thickness and planar dimensions, the thickness ratio of each layer, etc., differ from the actual ones. Furthermore, the embodiments shown below are merely examples of configurations for embodying the technical idea of ​​the present invention, and the technical idea of ​​the present invention does not specify the materials, shapes, structures, etc. of the components to be described below. The technical idea of ​​the present invention can be modified in various ways within the technical scope defined by the claims.

[0022] [Moisture-proof decorative paper 10 in Figure 1] As shown in FIG. 1, the moisture-proof decorative paper 10 according to the present invention is roughly divided into two layers, with a moisture-proof layer 30 laminated on the back surface of decorative paper 20. The decorative paper 20 is made up of three layers, a paper base material 21, a print pattern layer 22, and a protective resin layer 23, laminated in this order. The moisture-proof layer 30 is made up of three layers, that is, a layer 31 containing a polyvinyl alcohol resin, a vapor-deposited layer 32, and a layer 33 containing polyolefin, provided in this order on the back side of the paper substrate 21. The polyolefin-containing layer 33 is a layer containing a polyolefin having at least one selected from a carboxyl group, a salt of a carboxyl group, a carboxylic anhydride group, and a carboxylic acid ester.

[0023] [Moisture permeability of moisture-proof decorative paper 10] The moisture permeability of the moisture-proof decorative paper 10 is 5 g / m 2 24 hours or less is preferable, and less than 4 g / m is more preferable. 2 ·24hr or less, 3g / m 2 24 hours or less is preferable. The lower limit is 0 g / m 2 24 hours is also acceptable, and 0.1g / m 2 ·24hr or more, 0.3g / m 2 ·24hr or more, 0.5g / m 2 ·24hr or more, 1.0g / m 2 -24 hours or more is acceptable.

[0024] [Paper base material 21] The paper substrate 21 is not particularly limited and may be selected appropriately depending on the intended use of the moisture-proof decorative paper 10. Specific examples of the paper substrate 21 include tissue paper, fine paper, art paper, cast coated paper, kraft paper, titanium paper, linter paper, paperboard, gypsum board paper, fine paper, coated paper, parchment paper, glassine paper, parchment paper, paraffin paper, and Japanese paper. Preferably, thin paper in which synthetic resin is mixed to increase the strength between the sheets (so-called inter-sheet reinforced paper) or paper impregnated with latex or synthetic resin is used.

[0025] The basis weight is not particularly limited, but is preferably 20 g / m 2 Below 200g / m, the fabric is too flexible and wrinkles easily occur during processing. 2 In this case, peeling from the paper layer is likely to occur, so 20 to 200 g / m 2 is preferable, and 20 to 100 g / m2 More preferably, 20 to 50 g / m 2 is more preferred. Furthermore, the paper substrate 21 may be subjected to surface treatment such as corona treatment, plasma treatment, or flame treatment, if necessary.

[0026] The paper substrate 21 may be provided with a coating layer (not shown) at least on the side that contacts the layer 31 containing a polyvinyl alcohol-based resin, which will be described later. The coating layer can prevent the layer 31 containing a polyvinyl alcohol-based resin from penetrating into the paper, and can also serve as a sealant that fills in unevenness in the paper, allowing the layer 31 containing a polyvinyl alcohol-based resin to be formed uniformly without defects.

[0027] The coating layer may contain, for example, various copolymers such as styrene-butadiene, styrene-acrylic, and ethylene-vinyl acetate copolymers, polyvinyl alcohol resins, cellulose resins, paraffin (wax), etc. as binder resins, and may also contain clay, kaolin, calcium carbonate, talc, mica, etc. as fillers. The thickness of the coating layer is not particularly limited, but may be, for example, 1 to 10 μm, or 3 to 8 μm.

[0028] The weight of the paper substrate 21 is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, based on the weight of the moisture-proof layer 30. If the weight of the paper substrate 21 is 50% by mass or more based on the weight of the moisture-proof layer 30, the amount of plastic material used can be sufficiently reduced, and the moisture-proof decorative paper 10 can be said to be made of paper.

[0029] [Printed pattern layer 22] The printed pattern layer 22 is intended to impart design, and any pattern can be used as the pattern, such as a wood grain pattern, a stone pattern, a fabric pattern, a cork pattern, an abstract pattern, or a combination of two or more of these. A solid ink layer can be provided between the printed pattern layer 22 and the paper substrate 21 to ensure hiding power. The printing method is not particularly limited, and known printing methods such as gravure printing, offset printing, silk screen printing, and inkjet printing can be used.

[0030] There are no particular limitations on the printing ink, etc., and either oil-based or water-based inks are acceptable. The same printing inks as those used for the print pattern layer of conventional decorative paper can be used, such as acrylic ink. For example, a two-component curing urethane resin ink made by blending an isocyanate curing agent with an acrylic polyol vehicle can be used as the acrylic ink.

[0031] [Protective resin layer 23] The protective resin layer 23 is a layer for protecting the surface of the moisture-proof decorative paper 10. The protective resin layer 23 is provided to impart surface properties such as scratch resistance, abrasion resistance, stain resistance, water resistance, and weather resistance required for the moisture-proof decorative paper 10, the moisture-proof decorative board A100, the moisture-proof decorative board B101, and fittings such as doors. There are no particular limitations on the formation of the protective resin layer 23, and it can be formed by a known coating method such as gravure coating. There are no particular restrictions on the material of the protective resin layer 23, and it is possible to use materials similar to those used for the protective resin layer 23 in conventional decorative paper. For example, acrylic urethane resins and ionizing radiation curable resins can be used.

[0032] The acrylic urethane resin may be, for example, a reaction product of an acrylic polyol compound as a base compound and an isocyanate compound as a curing agent. The ionizing radiation curable resin may be, for example, a composition whose main component is at least one of a prepolymer, oligomer, and monomer having a polymerizable unsaturated bond such as a (meth)acryloyl group, which undergoes a crosslinking reaction upon irradiation with ionizing radiation such as electron beams or ultraviolet rays.

[0033] The protective resin layer 23 may be a single layer or may be a multi-layer consisting of two or three layers. In the case of a multi-layer structure, a glossy matte appearance can be achieved by separately applying a matte resin and a glossy resin. It is also possible to achieve a textured appearance by partially raising the resin. Furthermore, an antibacterial agent, an antiviral agent, etc. can be added.

[0034] [Layer 31 containing polyvinyl alcohol-based resin] The layer 31 containing a polyvinyl alcohol resin is provided on the surface of the paper substrate 21 in order to improve adhesion between the paper substrate 21 and the vapor-deposited layer 32 . Examples of polyvinyl alcohol resins include fully saponified polyvinyl alcohol resins, partially saponified polyvinyl alcohol resins, modified polyvinyl alcohol resins, and ethylene-vinyl alcohol copolymer resins. The degree of polymerization of the polyvinyl alcohol resin is preferably 300 or more and 1500 or less. If the degree of polymerization is 300 or more, the moisture-proof layer 30 will have good barrier properties and flex resistance, and if the degree of polymerization is 1500 or less, the viscosity of the coating liquid of the polyvinyl alcohol resin will be low, resulting in good coatability.

[0035] The layer 31 containing the polyvinyl alcohol resin can be provided by applying a coating liquid containing the polyvinyl alcohol resin and a solvent onto the paper substrate 21 and drying it. Examples of solvents contained in the coating liquid include water, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-propyl alcohol, n-butyl alcohol, n-pentyl alcohol, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, etc., and particularly preferred are mixed solvents of water and alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, etc. The coating liquid may also contain additives such as surfactants, preservatives, storage stabilizers, silane coupling agents, and organic titanates.

[0036] Such a layer 31 containing a polyvinyl alcohol-based resin has excellent flexibility, can suppress cracking of the vapor-deposited layer 32, and can improve adhesion between the vapor-deposited layer 32 and the layer 31 containing a polyvinyl alcohol-based resin.

[0037] The thickness of the layer 31 containing a polyvinyl alcohol resin may be, for example, 1 μm or more, 2 μm or more, or 5 μm or less. If the thickness is 1 μm or more, the irregularities of the paper substrate 21 can be efficiently filled, and the vapor-deposited layer 32 can be laminated uniformly. Furthermore, if the thickness is 5 μm or less, the vapor-deposited layer 32 can be laminated uniformly while keeping costs down.

[0038] [Vapour-deposited layer 32] The vapor-deposited layer 32 is a layer formed by vapor-depositing a metal or an inorganic compound. The vapor-deposited layer 32 may be obtained by vapor-depositing aluminum, or may contain aluminum oxide (AlOx), silicon oxide (SiOx), or the like.

[0039] The thickness of the vapor-deposited layer 32 may be appropriately set depending on the intended use, but is preferably 30 nm or more, 50 nm or more, and may be 100 nm or less, 80 nm or less. A thickness of 30 nm or more of the vapor-deposited layer 32 makes it easy to ensure sufficient continuity of the vapor-deposited layer 32, while a thickness of 100 nm or less makes it easy to sufficiently suppress the occurrence of curling and cracking, and to easily achieve sufficient gas barrier performance and portability.

[0040] From the viewpoint of barrier performance and film uniformity, it is preferable to form the deposition layer 32 by a vacuum deposition method. While known deposition methods include vacuum evaporation, sputtering, and chemical vapor deposition (CVD), vacuum deposition is preferred due to its fast deposition rate and high productivity. Among vacuum deposition methods, electron beam heating is particularly effective because it allows for easy control of the deposition rate through the irradiation area and electron beam current, and allows for rapid heating and cooling of the deposition material.

[0041] [Polyolefin-containing layer 33] The polyolefin-containing layer 33 is provided on the surface of the vapor-deposited layer 32 so as to be in contact with the vapor-deposited layer 32, and contains a polyolefin having at least one selected from a carboxyl group, a salt of a carboxyl group, a carboxylic anhydride group, and a carboxylic acid ester.

[0042] The layer 33 containing such a polyolefin has excellent flexibility, can suppress cracking of the vapor-deposited layer 32, and has excellent adhesion to the vapor-deposited layer 32. Furthermore, by including a polyolefin, it is possible to obtain a moisture-proof layer 30 with excellent water vapor barrier properties.

[0043] The polyolefin-containing layer 33 may contain other components in addition to the polyolefin. Examples of other components include silane coupling agents, organic titanates, polyacrylics, polyesters, polyurethanes, polycarbonates, polyureas, polyamides, polyolefin emulsions, polyimides, melamine, and phenols.

[0044] The content of polyolefin in the polyolefin-containing layer 33 may be, for example, 50% by mass or more, 70% by mass or more, 90% by mass or more, or 100% by mass.

[0045] The thickness of the polyolefin-containing layer 33 may be, for example, 2 μm or more, 3 μm or more, 10 μm or less, 8 μm or less, or 5 μm or less. Furthermore, if the thickness of the polyolefin-containing layer 33 is 10 μm or less, the adhesion to the vapor deposition layer 32 and the barrier properties can be sufficiently exhibited while keeping costs down.

[0046] The polyolefin-containing layer 33 can be provided by applying a coating liquid containing polyolefin and a solvent onto the vapor-deposited layer 32 and drying it. Examples of solvents contained in the coating liquid include water, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-propyl alcohol, n-butyl alcohol, n-pentyl alcohol, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, toluene, hexane, heptane, cyclohexane, acetone, methyl ethyl ketone, diethyl ether, dioxane, tetrahydrofuran, ethyl acetate, and butyl acetate. These solvents may be used alone or in combination of three or more. Among these, methyl alcohol, ethyl alcohol, isopropyl alcohol, toluene, ethyl acetate, methyl ethyl ketone, and water are preferred from the viewpoint of properties, and methyl alcohol, ethyl alcohol, isopropyl alcohol, and water are preferred from the viewpoint of the environment.

[0047] [Back moisture-proof sheet A11 in Figure 2] The back moisture-proof sheet A11 is a modified version of the moisture-proof decorative paper 10 of Figure 1, and as shown in Figure 2, an adhesive primer layer 40 is provided on the exposed surface of the polyolefin-containing layer 33 of the moisture-proof decorative paper 10 of Figure 1. The back surface moisture-proof sheet A11 is roughly divided into three layers, which are laminated in the order of adhesive primer layer 40, moisture-proof layer 30, and decorative paper 20. The decorative paper 20 has the same structure as that shown in FIG. 1, and is made up of three layers, namely, a paper base material 21, a print pattern layer 22, and a protective resin layer 23, which are laminated in this order.

[0048] The moisture-proof layer 30 has the same structure as in Fig. 1, and is made up of three layers, laminated in the order of polyolefin-containing layer 33, vapor-deposited layer 32, and polyvinyl alcohol-based resin-containing layer 31. The polyvinyl alcohol-based resin-containing layer 31 is adjacent to the paper substrate 21 of the decorative paper 20. The polyolefin-containing layer 33 is adjacent to the adhesive primer layer 40. The polyolefin-containing layer 33 is a layer containing polyolefin having at least one selected from a carboxyl group, a salt of a carboxyl group, a carboxylic anhydride group, and a carboxylic acid ester, similar to the moisture-proof decorative paper 10 of FIG.

[0049] The back moisture-proof sheet A11 has the same moisture permeability as the moisture-proof decorative paper 10 in FIG. 1, for example, 5 g / m 2 Moisture permeability of 24 hours or less is preferred. The backside moisture-proof sheet A11 can be, for example, a moisture-proof sheet having a metal-deposited film and a coating layer on a synthetic resin substrate. However, from the environmental perspective of reducing the amount of plastic used, a moisture-proof sheet having a moisture-proof layer on a paper substrate is preferred.

[0050] [Adhesion primer layer 40] The adhesive primer layer 40 is provided for the purpose of ensuring sufficient adhesion with various laminating adhesives, such as isocyanate-curing urethane resins and modified vinyl acetate resin emulsions, which are used when laminating onto the surface of various substrates. Known materials for this primer include various types of primers such as ester resins, urethane resins, acrylic resins, polycarbonate resins, vinyl chloride-vinyl acetate copolymers, polyvinyl butyral resins, and nitrocellulose resins, and one of these is selected to match the type of laminating adhesive.

[0051] For example, when a modified vinyl acetate resin emulsion adhesive is used as the laminating adhesive, good adhesion can be obtained with a urethane adhesive primer. Furthermore, if an inorganic fine powder such as silica is added to the adhesive primer agent, the surface of the adhesive primer layer 40 is roughened, which not only prevents blocking when the moisture-proof sheet is rolled up and stored, but also improves adhesion to the laminating adhesive due to its anchoring effect. Furthermore, these adhesive primer layers 40 can be formed alone or in combination to form an adhesive composition using an appropriate application method such as roll coating or gravure printing.

[0052] [Moisture-proof decorative board A100 in Figure 3] As shown in FIG. 3, the moisture-proof decorative board A100 is made up of moisture-proof decorative paper 10, board substrate 110, and back moisture-proof sheet A11, and is roughly divided into three layers. The moisture-proof decorative paper 10 used is that shown in FIG. 1, and the back moisture-proof sheet A11 used is that shown in FIG. The moisture-proof decorative paper 10 and the back moisture-proof sheet A11 are attached with adhesive to the front and back surfaces of the board substrate 110. In this way, a moisture-proof decorative board A100 that has been treated to prevent warping is obtained. In this case, the moisture-proof decorative paper 10 has the polyolefin-containing layer 33 shown in Figure 1 disposed on the surface adjacent to the board substrate 110. The back moisture-proof sheet A11 has the adhesive primer layer 40 shown in Figure 2 disposed on the surface adjacent to the board substrate 110.

[0053] [Plate base material 110] The board substrate 110 may be a wood-based board substrate such as medium density fiberboard (MDF), plywood, or particle board.

[0054] [Moisture-proof decorative board B101 shown in Figure 4] The moisture-proof decorative board B101 is a modified version of the moisture-proof decorative board A100 shown in Figure 3, and as shown in Figure 4, it consists of moisture-proof decorative paper 10 / board substrate 110 / backside moisture-proof sheet B12, and is roughly divided into three layers. The moisture-proof decorative paper 10 and board substrate 110 are the same as those of the moisture-proof decorative board A100 in FIG.

[0055] [Back moisture-proof sheet B12] The back moisture-proof sheet B12 is another variation of the moisture-proof decorative paper 10 in Figure 1, and consists of four layers, laminated in the order of paper base material 21 / layer 31 containing polyvinyl alcohol-based resin / vapor-deposited layer 32 / layer 33 containing polyolefin. The back moisture-proof sheet B12 is made by laminating, in this order, a moisture-proof layer 30 having the same structure as the moisture-proof layer 30 of the moisture-proof decorative paper 10, a layer 31 containing a polyvinyl alcohol resin, a vapor-deposited layer 32, and a layer 33 containing a polyolefin having at least one selected from a carboxyl group, a salt of a carboxyl group, a carboxylic anhydride group, and a carboxylic acid ester on an unprinted paper substrate 21; and an adhesive primer layer 40 (not shown) can be provided on the exposed surface of the moisture-proof layer 30.

[0056] The back moisture-proof sheet B12, like the back moisture-proof sheet A11, has the same moisture permeability as the moisture-proof decorative paper 10 in FIG. 1, for example, 5 g / m 2 Moisture permeability of 24 hours or less is preferred. The backside moisture-proof sheet B12 may be a moisture-proof sheet having a metal vapor-deposited film and a coating layer on a synthetic resin substrate, similar to the backside moisture-proof sheet A11. However, from the environmental perspective of reducing the amount of plastic used, a moisture-proof sheet having a moisture-proof layer on a paper substrate is preferred. The back moisture-proof sheet B12 is then attached with an adhesive to the back surface of the board substrate 110. In this way, a moisture-proof decorative board B101 that has been prevented from warping is obtained. In this case, the back moisture-proof sheet B12 has the polyolefin-containing layer 33 shown in FIG. 4 disposed on the surface adjacent to the plate substrate 110.

[0057] (Part of the doors and other fixtures in Figures 5 and 6) As shown in FIG. 5, some fittings such as doors are made up of a moisture-proof decorative board A100 / core assembly member 120 / moisture-proof decorative board A100, which can be broadly divided into three layers. Furthermore, some of the other fittings, such as doors, are made up of a moisture-proof decorative board B101 / core member 120 / moisture-proof decorative board B101, as shown in FIG. 6, and are roughly divided into three layers. As shown in Figs. 5 and 6, some of the fittings are flush doors or the like that are made by using moisture-proof decorative boards A100 or B101 on both sides of doors and are flush-processed. The moisture-proof decorative board A100 or B101 is pressure-bonded to the front and back surfaces of a wooden core member 120 using an adhesive, and is used as a fixture such as a flush door that is warp-resistant.

[0058] At this time, the moisture-proof decorative board A100 in FIG. 5 is pressed with the back moisture-proof sheet A11 facing inward using an adhesive, and the moisture-proof decorative board B101 in FIG. 6 is pressed with the back moisture-proof sheet B12 facing inward using an adhesive. The core member 120 can be made of wood-based board material such as medium density fiberboard (MDF), plywood, particle board, etc., and the flush door can also use core materials such as honeycomb panels. The adhesive used in the present invention is not limited to, for example, aqueous adhesives, solvent adhesives, chemical reaction adhesives, hot melt adhesives, etc. Any type of adhesive may be used. Known or commercially available adhesives may be appropriately selected and used.

[0059] (Features and Effects of the Embodiments Based on the Present Invention) The features of the embodiment of the present invention are as follows. (First feature) The decorative paper 20 of the first characteristic feature is, for example, as shown in Figure 1, composed of a paper base material 21, a printed pattern layer 22, and a protective resin layer 23 laminated in this order, and the moisture-proof layer 30 is composed of a layer 31 containing a polyvinyl alcohol-based resin, a vapor-deposited layer 32, and a layer 33 containing a polyolefin having at least one selected from a carboxyl group, a salt of a carboxyl group, a carboxylic anhydride group, and a carboxylic acid ester, provided in this order on the back side of the paper base material 21.

[0060] (Effect of the first feature) According to the first characteristic, moisture permeability can be significantly reduced, and warping of fittings such as doors can be prevented even when used in a location where there is a large difference in temperature and humidity environment on both sides. Furthermore, according to the first characteristic point, it can contribute to reducing the amount of plastic material used, and since it is made of wood material and paper components, it is also highly recyclable. Specifically, as shown in Tables 1 and 2 below, in the examples and comparative examples, the moisture permeability (JIS Z 0208) is 5.0 g / m 2 -Because it lasts for 24 hours or less, it has significantly better moisture-proofing performance than moisture-proof sheets made of synthetic resins such as vinyl chloride, polyethylene, polypropylene, etc., or paper / polyethylene / paper.

[0061] (Second feature) The second feature is that the thickness of the layer 31 containing the polyvinyl alcohol resin is 1 μm or more and 5 μm or less.

[0062] (Effect of the second feature) According to the second feature, when the thickness of the layer 31 containing the polyvinyl alcohol resin is 1 μm or more, the irregularities of the paper substrate 21 can be efficiently filled, and the vapor-deposited layer 32 can be laminated uniformly. Furthermore, if the thickness is 5 μm or less, the deposition layer 32 can be laminated uniformly while keeping costs down.

[0063] (Third feature) A third feature is that the thickness of the deposition layer 32 is 30 nm or more and 100 nm or less.

[0064] (Effect of the third feature) According to the third feature, by making the thickness of the vapor deposition layer 32 30 nm or more, it is easy to ensure sufficient continuity of the vapor deposition layer 32, and by making it 100 nm or less, it is possible to sufficiently suppress the occurrence of curling and cracking, and it is easy to achieve sufficient gas barrier performance and flexibility.

[0065] (Fourth feature) A fourth feature is that the thickness of the polyolefin-containing layer 33 is 2 μm or more and 10 μm or less.

[0066] (Effect of the fourth feature) According to the fourth feature, the thickness of the polyolefin-containing layer 33 is 2 μm or more and 10 μm or less, so that the adhesion to the vapor deposition layer 32 and the barrier properties can be sufficiently exhibited while keeping costs down.

[0067] (5th feature) A fifth characteristic is that the weight of the paper substrate 21 is 50% by mass or more based on the entire moisture-proof layer 30.

[0068] (Effect of the fifth feature) According to the fifth feature, if the content is 50 mass % or more, the amount of plastic material used can be sufficiently reduced. That is, according to the fifth characteristic point, it contributes to reducing the amount of plastic material used, and since it is made of wood material and paper components, it is also highly recyclable.

[0069] (6th feature) A sixth feature is that an adhesive primer layer 40 is provided on the outer surface of the moisture-proof layer 30, as shown in FIG.

[0070] (Effect of the 6th feature) According to the sixth feature, the adhesive primer layer 40 can be used for laminating and adhering to the surface of various substrates. For example, sufficient adhesion is ensured with various laminating adhesives such as isocyanate-curing urethane resins and modified vinyl acetate resin emulsions. Furthermore, by adding, for example, inorganic fine powder to the adhesive primer layer 40, the surface of the adhesive primer layer 40 is roughened, which not only prevents blocking when the moisture-proof decorative paper 10 is rolled up and stored, but also improves adhesion with the laminating adhesive due to the anchoring effect.

[0071] Furthermore, by adding inorganic fine powder to the adhesive primer, the surface of the adhesive primer layer 40 is roughened, which not only prevents blocking when the moisture-proof decorative paper 10 is rolled up and stored, but also improves adhesion with the laminating adhesive due to its anchoring effect.

[0072] (7th feature) A seventh feature is that the paper base material 21 is a reinforced inter-sheet paper.

[0073] (Effect of the seventh feature) According to the seventh characteristic point, by using inter-layer reinforced paper, it is possible to prevent the paper layers from peeling from between the layers when the product is used for a long period of time or when an unavoidable external force is applied.

[0074] (8th feature) The eighth feature is that the moisture-proof decorative paper 10 is attached to one surface of a board substrate 110 such as plywood as shown in Figs. 3 and 4, and the moisture-proof decorative paper 10 is made of a material having a moisture permeability of 5 g / m 2 A back moisture-proof sheet (for example, back moisture-proof sheet A11, back moisture-proof sheet B12) having a durability of 24 hours or less was attached to the other side of the plate substrate 110.

[0075] (Effect of the 8th feature) According to the eighth characteristic, moisture permeability can be significantly reduced, and warping of the moisture-proof decorative board (for example, moisture-proof decorative board A100, moisture-proof decorative board B101) can be prevented even when used in a location where there is a large difference in temperature and humidity environment on both sides.

[0076] (9th feature) The ninth feature is that, as shown in Figures 1 and 2, for example, a moisture-proof layer 30 is laminated on the back surface of a paper substrate 21. The moisture-proof layer 30 is composed of a layer 31 containing a polyvinyl alcohol-based resin, a vapor-deposited layer 32, and a layer 33 containing a polyolefin having at least one selected from a carboxyl group, a salt of a carboxyl group, a carboxylic anhydride group, and a carboxylic acid ester, which are provided in this order on the back surface side of the paper substrate 21.

[0077] (Effect of the 9th feature point) According to the ninth feature, moisture permeability can be significantly reduced, and even when used in a location where there is a large difference in temperature and humidity environment on both sides, warping of the moisture-proof decorative board (e.g., moisture-proof decorative board A100, moisture-proof decorative board B101) can be prevented, as shown in Figures 3 and 4.

[0078] (10th feature) The tenth feature is that moisture-proof decorative panels (e.g., moisture-proof decorative panels A100, B101) are pressed onto the front and back surfaces of the wood-based core member 120, with the back moisture-proof sheet (e.g., back moisture-proof sheet A11, back moisture-proof sheet B12, see Figures 3 and 4, for example) facing inward, as shown in Figures 5 and 6.

[0079] (Effect of the 10th feature) According to the tenth characteristic point, moisture permeability can be significantly reduced, and warping of doors and other fixtures can be prevented even when used in a location where there is a large difference in temperature and humidity environment on both sides.

[0080] (11th feature) An eleventh feature is that, as shown in Figure 4, a moisture-proof layer 30 and decorative paper 20 are laminated in this order on the surface of the board substrate 110 to form moisture-proof decorative paper 10, and the moisture-proof layer 30 and an unprinted paper substrate 21 are laminated in this order on the back surface of the board substrate 110, and an adhesive primer layer 40 can be provided on the outer surface of the paper substrate 21.

[0081] (Effect of the 11th feature point) According to the eleventh feature, an adhesive primer layer 40 can be used. [Example]

[0082] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to the following examples in any way. Example 1 50 g / m as paper base material 21 2 A coating solution of polyvinyl alcohol resin with a saponification degree of 98% and a polymerization degree of 500 dissolved in a water / IPA solution at a solids concentration of 10% by mass was applied to the surface of the reinforced paper (manufactured by Tenma Tokushu Paper Co., Ltd.) using a bar coater, and then dried in an oven to form a layer containing polyvinyl alcohol resin. The layer had a thickness of 3 μm. Subsequently, aluminum was deposited on the polyvinyl alcohol resin layer by vacuum deposition, resulting in an aluminum deposition layer with a thickness of 50 nm.

[0083] A coating solution containing a carboxyl group salt (product name: Chemipearl S500, manufactured by Mitsui Chemicals) was then applied onto the vapor-deposited layer using a bar coater and dried in an oven to form a polyolefin-containing layer, yielding a moisture-proof layer. The polyolefin-containing layer had a thickness of 3 μm. Next, a solid ink layer was applied by gravure printing to the surface of the paper substrate opposite the moisture-proof layer using an ink containing soluble nitrocellulose and acrylic resin as a binder, and a pattern ink layer was applied on top of that by gravure printing using an ink also containing soluble nitrocellulose and acrylic resin as a binder. Subsequently, a protective resin layer was applied by gravure printing using a urethane-based acrylic polyol and isocyanate, and the moisture-proof decorative paper of Example 1 was obtained.

[0084] Example 2 A moisture-proof decorative paper of Example 2 was obtained in the same manner as in Example 1, except that the thickness of the layer containing the polyvinyl alcohol resin was 1 μm.

[0085] Example 3 A moisture-proof decorative paper of Example 3 was obtained in the same manner as in Example 1, except that the thickness of the polyolefin-containing layer was set to 2 μm.

[0086] Example 4 A moisture-proof decorative paper of Example 4 was obtained in the same manner as in Example 1, except that the thickness of the polyolefin-containing layer was set to 10 μm.

[0087] Example 5 The moisture-proof decorative paper of Example 5 was obtained in the same manner as in Example 1, except that the vapor-deposited layer was made of silica and had a thickness of 30 nm.

[0088] Example 6 A moisture-proof decorative paper of Example 6 was obtained in the same manner as in Example 1, except that the vapor-deposited layer was made of alumina and had a thickness of 30 nm.

[0089] Example 7 50g / m as paper base material 2 A coating solution of polyvinyl alcohol resin with a saponification degree of 98% and a polymerization degree of 500 dissolved in a water / IPA solution at a solids concentration of 10% by mass was applied to one side of a reinforced paper for paper (manufactured by Tenma Tokushu Paper Co., Ltd.) using a bar coater, and then dried in an oven to form a layer containing polyvinyl alcohol resin. The layer had a thickness of 3 μm. Subsequently, aluminum was deposited on the polyvinyl alcohol resin layer by vacuum deposition, resulting in an aluminum deposition layer with a thickness of 50 nm. Then, a coating solution containing a carboxyl group salt (product name: Chemipearl S500, manufactured by Mitsui Chemicals) was applied to the vapor-deposited layer using a bar coater and dried in an oven to form a polyolefin-containing layer, thereby obtaining a back moisture-proof sheet with a moisture-proof layer. The polyolefin-containing layer at this time had a thickness of 3 μm.

[0090] The moisture-proof layer side of the moisture-proof decorative paper obtained in Example 1 was used as the adhesive side and laminated to the front surface of an MDF board substrate (3 mm, manufactured by Hokushin Co., Ltd.), and the moisture-proof layer side of the back moisture-proof sheet was used as the adhesive side and laminated to the back surface of the board substrate using a vinyl acetate resin adhesive (manufactured by Konishi Co., Ltd.) (5 g / shaku, wet), to obtain a moisture-proof decorative board with anti-warping properties. Next, a flush door (810mm x 2030mm) of Example 7 was created by attaching the moisture-proof decorative panel with the moisture-proof sheet side on the back and front of a four-sided frame made of LVL (27mm x 26mm, manufactured by First Wood Co., Ltd.) facing inward, using a vinyl acetate resin adhesive (manufactured by Konishi Co., Ltd.).

[0091] Example 8 A flush door of Example 8 was obtained in the same manner as in Example 7, except that the moisture-proof decorative paper obtained in Example 5 was used.

[0092] Example 9 A flush door of Example 9 was obtained in the same manner as in Example 7, except that the moisture-proof decorative paper obtained in Example 6 was used.

[0093] (Comparative Example 1) The moisture-proof decorative paper of Comparative Example 1 was obtained by the same procedure as in Example 1, except that a coating liquid containing a vinyl acetate-based polyolefin resin (product name: Chemipearl V300, manufactured by Mitsui Chemicals) was used instead of the coating liquid containing polyvinyl alcohol resin.

[0094] (Comparative Example 2) A moisture-proof decorative paper of Comparative Example 2 was obtained in the same manner as in Example 1, except that no vapor deposition layer was provided.

[0095] (Comparative Example 3) As a conventional moisture-proof sheet, a 30g / m2 sheet with corona treatment on one side was used. 2 The corona-treated surfaces of the above-mentioned reinforced inter-paper sheets (manufactured by Tenma Tokushu Paper Co., Ltd.) were sandwich-laminated with 50 μm of molten polyethylene resin extruded from a T-die extruder to produce a moisture-proof sheet (reinforced inter-paper sheets / polyethylene / reinforced inter-paper sheets). Next, a solid ink layer was applied to the exposed surface of the moisture-proof sheet by gravure printing using an ink containing soluble nitrocellulose and acrylic resin as a binder, as in Example 1. A pattern ink layer was then applied thereon by gravure printing using an ink also containing soluble nitrocellulose and acrylic resin as a binder. Subsequently, a protective resin layer was applied by gravure printing using a urethane-based acrylic polyol and isocyanate, thereby obtaining a moisture-proof decorative sheet of Comparative Example 3.

[0096] Comparative Example 4 The moisture-proof decorative sheet obtained in Comparative Example 3 was laminated to the surface of an MDF board substrate (3 mm, manufactured by Hokushin Co., Ltd.), and a moisture-proof sheet (reinforced paper / polyethylene / reinforced paper) was laminated to the back of the board substrate using a vinyl acetate resin adhesive (manufactured by Konishi Co., Ltd.), resulting in a moisture-proof decorative board with anti-warping properties. Next, a flush door (810mm x 2030mm) of Comparative Example 4 was created by attaching the moisture-proof sheet side of the moisture-proof decorative panel to the front and back of a four-sided frame made of a core assembled with LVL (27mm x 26mm, manufactured by First Wood Co., Ltd.) with the moisture-proof sheet side facing inward, using a vinyl acetate resin adhesive (manufactured by Konishi Co., Ltd.).

[0097] (Comparative Example 5) 50g / m 2 A solid ink layer was applied to one side of a reinforced paper (manufactured by Tenma Tokushu Paper Co., Ltd.) by gravure printing using an ink containing soluble nitrocellulose and acrylic resin as a binder, as in Example 1. A pattern ink layer was then applied thereon by gravure printing using an ink also containing soluble nitrocellulose and acrylic resin as a binder. Subsequently, a protective resin layer was applied by gravure printing using a urethane-based acrylic polyol and isocyanate, and the decorative paper of Comparative Example 5 was obtained.

[0098] The decorative paper obtained above was applied to the surface of an MDF board substrate (manufactured by Hokushin Co., Ltd.: 3 mm) at a rate of 50 g / m 2 The backside of the laminate was laminated with a reinforced inter-paper paper (manufactured by Tenma Tokushu Seishi Co., Ltd.) using a vinyl acetate resin adhesive (manufactured by Konishi Co., Ltd.) to obtain a decorative board. Next, a flush door (810mm x 2030mm) of Comparative Example 5 was created using a vinyl acetate resin adhesive (manufactured by Konishi Co., Ltd.) on the front and back of a four-sided frame assembled with a core of LVL (manufactured by First Wood Co., Ltd.: 27mm x 26mm) with the paper tube reinforced paper side facing inward on the back side.

[0099] <Rating 1> The moisture permeability of the moisture-proof decorative papers of Examples 1 to 6 and the moisture-proof decorative papers and moisture-proof sheets of Comparative Examples 1 to 3 prepared above was calculated in accordance with JIS Z 0208, and a comparison of the moisture permeability was made. The results are shown in Tables 1 and 2. [Table 1]

[0100] [Table 2]

[0101] As is clear from the results in Tables 1 and 2, the moisture-proof decorative papers of Examples 1 to 6 had significantly lower moisture permeability than the moisture-proof decorative papers and moisture-proof sheets of Comparative Examples 1 to 3.

[0102] <Rating 2> The flush doors produced in Examples 7 to 9 and Comparative Examples 4 and 5 were subjected to a warpage test in a two-chamber one-piece environmental test chamber. As a test method, a flush door was placed at the boundary between two rooms, one side was placed in a high humidity environment and the other side was placed in a low humidity environment, and the amount of warping of the door was measured. The test method was detailed as follows: the high humidity side was kept at a humidity of 90% ± 5% and a temperature of 20°C, and the low humidity side was kept at a humidity of 50% ± 5%. The samples were left at 20°C for 8 hours, and then both chambers were left at a humidity of 50% ± 5% and a temperature of 20°C for 16 hours. This 24-hour cycle was repeated for five cycles of humidification. At this time, the maximum displacements in the vertical, horizontal and diagonal directions were measured. The results are shown in Table 3. [Table 3]

[0103] This has enabled us to verify that it is possible to provide moisture-proof decorative panels and doors and other fittings that can prevent warping even when used in places where there is a large difference in temperature and humidity environments on both sides, which is the objective of this invention.

[0104] <Evaluation result 1> (Comparison of Examples 1 to 6 with Comparative Examples 1 to 3) Using Tables 1 and 2, the moisture-proof decorative papers according to Examples 1 to 6 and the moisture-proof decorative papers according to Comparative Examples 1 to 3 were compared in terms of moisture permeability. The moisture permeability of moisture-proof decorative paper is 5g / m 2 As shown in Table 1, all of Examples 1 to 6 passed the test, with a test time of 24 hours or less being considered acceptable. In contrast, as shown in Table 2, all of Comparative Examples 1 to 3 failed.

[0105] It is presumed that the reason for this is that, compared to Example 1, Comparative Example 1 used a "coating liquid containing a vinyl acetate-based polyolefin resin" (product name: Chemipearl V300, manufactured by Mitsui Chemicals) instead of a "coating liquid containing a polyvinyl alcohol resin." It can be assumed that this is because Comparative Example 2 does not have a "vapor deposition layer" compared to Example 1. This is presumably because, compared to Example 1, Comparative Example 3 does not have a "vapor deposition layer" and also does not have a "layer containing a polyvinyl alcohol-based resin" or a "layer containing a polyolefin."

[0106] <Evaluation result 2> (Comparison of Examples 7 to 9 with Comparative Examples 4 and 5) A maximum displacement of 5.0 mm or less for the flush door was deemed acceptable, and as shown in Table 3, Examples 7 to 9 all passed. In contrast, as shown in Table 3, Comparative Examples 4 and 5 all failed. In comparison with Example 7, it is presumed that the reason for this is that Comparative Example 4 used the moisture-proof decorative sheet obtained in Comparative Example 3. In comparison with Example 7, it is presumed that the reason for this is that the decorative paper used in Comparative Example 5 does not have a "vapor deposition layer," a "layer containing a polyvinyl alcohol-based resin," or a "layer containing a polyolefin," just like Comparative Example 3. [Explanation of symbols]

[0107] 10 Moisture-proof decorative paper 11 Back moisture-proof sheet A 12 Back moisture-proof sheet B 20 decorative paper 21 Paper base material 22 Printed pattern layer 23 Protective resin layer 30 Moisture barrier 31 Layer containing polyvinyl alcohol resin 32 Deposited layer 33 Polyolefin-containing layer 100 Moisture-proof decorative paper A 101 Moisture-proof decorative paper B 110 Plate base material 120 Core assembly member

Claims

1. A moisture-proof decorative paper having a moisture-proof layer laminated on the back surface of the decorative paper, The decorative paper is formed by laminating a paper base material, a print pattern layer, and a protective resin layer in this order, the moisture-proof layer is provided on the back surface side of the paper substrate with a layer containing a polyvinyl alcohol-based resin, a vapor-deposited layer, and a layer containing a polyolefin copolymer having a monomer unit having a salt of a carboxyl group, in this order; A moisture-proof decorative paper characterized in that an adhesive primer layer is provided on the outer surface of the moisture-proof layer.

2. 2. The moisture-proof decorative paper according to claim 1, wherein the thickness of the layer containing the polyvinyl alcohol resin is 1 μm or more and 5 μm or less.

3. 3. The moisture-proof decorative paper according to claim 1, wherein the thickness of the vapor-deposited layer is 30 nm or more and 100 nm or less.

4. 4. The moisture-proof decorative paper according to claim 1, wherein the thickness of the layer containing the polyolefin copolymer is 2 μm or more and 10 μm or less.

5. 5. The moisture-proof decorative paper according to claim 1, wherein the weight of the paper substrate is 50% by mass or more based on the entire moisture-proof layer.

6. The moisture-proof decorative paper according to any one of claims 1 to 5, wherein the paper base material is a reinforced inter-paper paper.

7. The moisture-proof decorative paper according to any one of claims 1 to 6 is stuck to one surface of a board substrate, and the moisture permeability is 5 g / m ２ A moisture-proof decorative board characterized in that a back moisture-proof sheet having a durability of 24 hours or less is attached to the other side of the board substrate.

8. The back moisture-proof sheet of the moisture-proof decorative board is formed by laminating a moisture-proof layer on the back surface of a paper base material, The moisture-proof decorative board according to claim 7, characterized in that the moisture-proof layer is formed by providing, in this order, a layer containing a polyvinyl alcohol-based resin, a vapor-deposited layer, and a layer containing a polyolefin copolymer having a monomer unit having a salt of a carboxyl group on the back side of the paper base material.

9. A fixture characterized in that the moisture-proof decorative board according to claim 7 or 8 is pressure-bonded to the front and back surfaces of a wooden core member with the back moisture-proof sheet side facing inward.

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