Moistureproof film for building material, and decorative plate

Abstract

To provide a moistureproof film for a building material which is excellent in concealment property while imparting moistureproof performance to a rear face of a decorative plate, and to reduce the number of processes by imparting concealment property to the rear face of the decorative plate without stacking a monochromatic decorative sheet thereon.SOLUTION: A moistureproof film for a building material has at least a resin base material, an inorganic layer and a barrier coat layer in this order, wherein the barrier coat layer contains a polyvinyl alcohol-based resin and a pigment.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a moisture-proof film for building materials and a decorative board. [Background technology]

[0002] 2. Description of the Related Art Decorative boards, which are formed by laminating a decorative sheet onto the surface of a wood-based substrate such as wood plywood, medium density fiberboard (MDF), hardboard, or particle board, have traditionally been used as surface materials for doors, sliding doors, partitions, flooring, and the like.

[0003] When the moisture content of the wood-based substrate is lower than the equilibrium moisture content of the wood-based substrate under outdoor conditions, the wood-based substrate absorbs moisture or water from the side of the decorative board where the decorative sheet is not laminated, causing this side to expand. On the other hand, when the moisture content of the wood-based substrate is higher than the equilibrium moisture content of the wood-based substrate under outdoor conditions, the wood-based substrate releases moisture or water, causing the substrate to shrink, whereas the side where the decorative sheet is laminated hardly absorbs or releases moisture or water, resulting in a difference in the expansion or contraction rate between the side where the decorative sheet is laminated and the side where the wood-based substrate is exposed, causing the decorative board to warp.

[0004] To prevent such warping of the wood-based substrate, for example, a method is known in which a moisture-proof film is laminated on the surface of the wood-based substrate opposite to the surface on which the decorative sheet is laminated.

[0005] For example, Patent Document 1 discloses a decorative board in which a moisture-proof film for building materials is laminated on one surface of a wood-based substrate via an adhesive layer, and a decorative sheet is laminated on the other surface of the wood-based substrate. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2017-177685 A Summary of the Invention [Problem to be solved by the invention]

[0007] In recent decorative boards, a single-color decorative sheet may be laminated on the surface of the wood-based base material opposite to the side on which the decorative sheet is laminated (also referred to as the back surface of the decorative board). However, when laminating a single-color decorative sheet on the back surface of the decorative board, the number of steps increases, leading to an increase in costs, and therefore, in some cases, the single-color decorative sheet is not laminated.

[0008] If a single-color decorative sheet is not laminated on the back surface of the decorative board, the wood-based base material is visible, resulting in a problem of poor design.

[0009] In the decorative board described in Patent Document 1, the design of the back surface of the decorative board has not been fully considered, and there is room for further improvement.

[0010] Therefore, the present disclosure provides a moisture-proof film for building materials that imparts moisture-proof performance to the back surface of a decorative board while also providing excellent concealment properties. In addition, since the concealing property can be imparted to the back surface of the decorative board without laminating a single-color decorative sheet, the number of steps can be reduced. [Means for solving the problem]

[0011] By using a moisture-proof film for building materials that has a resin substrate, an inorganic layer, and a barrier coat layer, at least in this order, and the barrier coat layer contains a polyvinyl alcohol-based resin and a pigment, it is possible to impart hiding properties to the decorative board in addition to moisture-proofing performance.

[0012] That is, the present disclosure provides a moisture-proof film for building materials, which comprises, at least in this order, a resin substrate, an inorganic layer, and a barrier coat layer, and the barrier coat layer contains a polyvinyl alcohol-based resin and a pigment.

[0013] In the moisture-proof film for building materials of the present disclosure, the barrier coat layer preferably contains 15% by mass or more and 65% by mass or less of the pigment based on the total mass of the barrier coat layer. The barrier coat layer preferably has a thickness of 0.1 μm or more and 3.0 μm or less. The resin substrate preferably has a thickness of 10 μm or more and 100 μm or less. The resin substrate preferably contains a biomass-derived component. The resin substrate preferably contains 5% by mass or more and 45% by mass or less of ethylene glycol derived from biomass, based on the total mass of the resin substrate. The present disclosure also relates to a decorative board comprising a wood-based substrate and a decorative sheet, at least in this order, on the side of the moisture-proof film for building materials that has a barrier coat layer. The decorative board of the present disclosure has the moisture-proof film for building materials and the wood-based substrate laminated together via an adhesive layer, and it is preferred that the adhesive layer contains a pigment. Effect of the Invention

[0014] The present disclosure provides a moisture-proof film for building materials that provides moisture-proof performance to the back surface of a decorative board while also providing excellent concealment. In addition, since the concealment can be provided without laminating a single-color decorative sheet to the back surface of the decorative board, the number of steps can be reduced. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a cross-sectional view for explaining a schematic diagram of a preferred example of the moisture-proof film for building materials according to the present disclosure. [Diagram 2] FIG. 2 is a cross-sectional view for explaining a schematic diagram of a preferred example of the decorative board of the present disclosure. [Diagram 3] FIG. 3 is a cross-sectional view for explaining a schematic example of a preferred example of the decorative board of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] <Moisture-proof film for building materials> The moisture-proof film for building materials of the present disclosure includes, at least in this order, a resin substrate, an inorganic layer, and a barrier coat layer, and the barrier coat layer contains a polyvinyl alcohol-based resin and a pigment.

[0017] The decorative board is provided with a resin substrate, an inorganic layer, and a barrier coat layer in this order, and the barrier coat layer is a moisture-proof film for building materials containing a polyvinyl alcohol resin and a pigment, so that the decorative board can be given not only moisture-proof performance but also concealing properties. In addition, since the concealing properties can be given without laminating a single-color decorative sheet on the back surface of the decorative board, the number of steps can be reduced, which is advantageous in terms of cost.

[0018] FIG. 1 is a cross-sectional view for explaining a schematic diagram of a preferred example of the moisture-proof film for building materials according to the present disclosure. As shown in FIG. 1, the moisture-proof film for building materials 10 includes at least a resin substrate 1, an inorganic layer 2, and a barrier coat layer 3, in this order, and the barrier coat layer 3 contains a polyvinyl alcohol-based resin and a pigment. Furthermore, a primer layer 4 may be provided on the side of the barrier coat layer 3 opposite to the side on which the inorganic layer 2 is provided. Each layer constituting the moisture-proof film for building materials of the present disclosure will be described in detail below.

[0019] (Resin substrate) The moisture-proof film for building materials of the present disclosure includes a resin substrate.

[0020] The resin substrate is not particularly limited, and a conventionally known resin film or resin sheet can be used.

[0021] Examples of resin films or resin sheets include polyester-based resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN); polyamide-based resins such as polyamide resin 6, polyamide resin 66, polyamide resin 610, polyamide resin 612, polyamide resin 11, and polyamide resin 12; and polyolefin-based resins such as α-olefin polymers such as polyethylene and polypropylene.

[0022] The resin substrate (resin film or resin sheet) preferably contains a biomass-derived component, and more preferably contains biomass-derived ethylene glycol. Specifically, it is more preferable to include a biomass polyester having ethylene glycol derived from biomass as the diol unit and a dicarboxylic acid derived from a fossil fuel as the dicarboxylic acid unit. By including a biomass-derived component in the resin base material, it is possible to reduce the use of raw materials derived from fossil fuels and reduce the environmental burden.

[0023] The resin substrate preferably contains 5% by mass or more and 45% by mass or less of ethylene glycol derived from biomass, based on the total mass of the resin substrate.

[0024] Carbon dioxide in the atmosphere contains a certain percentage of C14 (105.5 pMC), so it is known that the C14 content in plants that grow by absorbing carbon dioxide from the atmosphere, such as corn, is also about 105.5 pMC. It is also known that fossil fuels contain very little C14. Therefore, by measuring the proportion of C14 among all carbon atoms in a polyester, it is possible to determine whether or not the polyester is made from raw materials derived from biomass.

[0025] The resin film or resin sheet can be produced, for example, by using one or more of the above-mentioned resins and using a film-forming method such as an extrusion method, a cast molding method, a T-die method, a cutting method, an inflation method, or the like to form a film by multilayer co-extrusion using one or more of the above-mentioned resins, or by using two or more resins and mixing them before forming into a film. Furthermore, for example, a film stretched in a uniaxial or biaxial direction by using a tenter system or a tubular system can be used.

[0026] When one or more of the above resins are used to form a film, various plastic compounding agents and additives can be added for the purpose of improving or modifying, for example, the processability, heat resistance, weather resistance, mechanical properties, dimensional stability, oxidation resistance, slipperiness, release properties, flame retardancy, mildew resistance, electrical properties, strength, and the like of the film. The amount of the additive may range from a trace amount to several tens of percent, and may be arbitrarily selected depending on the purpose.

[0027] Examples of additives that can be used include lubricants, crosslinking agents, antioxidants, ultraviolet absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, and the like. Furthermore, modifying resins and the like may be used.

[0028] The resin substrate may be subjected to a surface treatment such as a saponification treatment, a glow discharge treatment, a corona discharge treatment, a plasma discharge treatment, an ultraviolet (UV) treatment, or a flame treatment.

[0029] The resin substrate preferably has a thickness of 10 μm or more and 100 μm or less. When the resin substrate has a thickness within the above range, abrasion resistance can be suitably imparted. The resin substrate more preferably has a thickness of 10 μm or more and 25 μm or less.

[0030] (Inorganic layer) The moisture-proof film for building materials of the present disclosure includes an inorganic layer.

[0031] The inorganic layer is preferably a vapor-deposited film of an inorganic substance or an inorganic oxide. The vapor-deposited film can be formed by a conventionally known method using a conventionally known inorganic substance or inorganic oxide, and the composition and the method of formation are not particularly limited. By providing the inorganic layer, it is possible to improve the gas barrier properties that prevent the permeation of oxygen gas, water vapor, and the like.

[0032] Examples of the deposited film that can be used include deposited films of inorganic substances or inorganic oxides such as silicon (Si), aluminum (Al), magnesium (Mg), calcium (Ca), potassium (K), tin (Sn), sodium (Na), boron (B), titanium (Ti), lead (Pb), zirconium (Zr), and yttrium (Y).

[0033] As a material suitable for building materials, it is preferable to use a vapor-deposited film of aluminum metal, or a vapor-deposited film of silicon oxide, aluminum metal, or aluminum oxide. Furthermore, when a high frequency wave is used to bond a moisture-proof film to wood during processing of a flush door, a transparent inorganic oxide vapor deposition layer is more preferable.

[0034] Inorganic oxides are expressed as, for example, SiO X , AlO X MO X (wherein, M represents an inorganic element, and the value of X varies depending on the inorganic element.) The value of x can range from 0 to 2 for silicon (Si), 0 to 1.5 for aluminum (Al), 0 to 1 for magnesium (Mg), 0 to 1 for calcium (Ca), 0 to 1 for potassium (K), 0 to 0.5 for tin (Sn), 0 to 2 for sodium (Na), 0 to 0.5 for boron (B), 0 to 1.5 for titanium (Ti), 0 to 2 for lead (Pb), 0 to 1 for zirconium (Zr), and 0 to 1.5 for yttrium (Y). In the above, when X=0, it is a completely inorganic element (pure substance) and is not transparent, and the upper limit of the range of X is the value at which it is completely oxidized. Silicon (Si) and aluminum (Al) are preferably used in building materials, and silicon (Si) with a value in the range of 1.0 to 2.0 and aluminum (Al) with a value in the range of 0.5 to 1.5 can be used.

[0035] The thickness of the vapor-deposited film varies depending on the type of inorganic substance or inorganic oxide used, but is preferably selected from the range of about 50 to 2000 Å, or about 100 to 1000 Å, for example.

[0036] In the case of an aluminum vapor deposition film, the thickness of the vapor deposition film is, for example, about 50 to 600 Å, and preferably about 100 to 450 Å. In the case of a vapor-deposited film of aluminum oxide or silicon oxide, the thickness of the vapor-deposited film is preferably about 50 to 500 Å, and more preferably about 100 to 300 Å.

[0037] Examples of methods for forming a vapor-deposited film include physical vapor deposition methods (PVD methods) such as vacuum deposition, sputtering, and ion plating, and chemical vapor deposition methods (CVD methods) such as plasma chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition.

[0038] (Barrier coat layer) The moisture-proof film for building materials of the present disclosure includes a barrier coat layer. The barrier coat layer contains a polyvinyl alcohol-based resin and a pigment.

[0039] The barrier coat layer is a layer having gas barrier properties, and is preferably a coating film. By providing the barrier coat layer, it is possible to improve the gas barrier properties that prevent the permeation of oxygen gas, water vapor, and the like.

[0040] The barrier coat layer can be formed, for example, by the following gas barrier coating film. The coating film is a coating film that retains gas barrier properties in a high-temperature and high-humidity environment, and is represented by the general formula R 1 n M(OR 2 ) m (In the formula, R 1 , R 2 represents an organic group having 1 to 8 carbon atoms, M represents a metal atom, n represents an integer of 0 or more, m represents an integer of 1 or more, and n+m represents the atomic valence of M. The coating film is made of a composition for a barrier coat layer, which contains at least one metal alkoxide represented by the formula (I) above, a polyvinyl alcohol resin, and a pigment, and is further obtained by polycondensation by a sol-gel method in the presence of a sol-gel catalyst, an acid, water, and an organic solvent.

[0041] The barrier coat layer composition can be applied onto the inorganic layer to provide a coating film, and then the coating film can be heated and dried for 10 seconds to 10 minutes at a temperature of 20°C to 180°C and below the melting point of the inorganic layer (vapor-deposited film). The inorganic layer may be coated with the coating film to form two or more overlapping layers, and the coating film may be heated and dried for 10 seconds to 10 minutes at a temperature of 20°C to 180°C and below the melting point of the inorganic layer (vapor-deposited film) to form a composite polymer layer with two or more overlapping layers of the coating film.

[0042] The metal alkoxide is represented by the above general formula R 1 n M(OR 2 ) m In the above, examples of the metal atom represented by M include silicon, zirconium, titanium, aluminum, and the like.

[0043] Two or more kinds of metal alkoxides may be used in combination. For example, by using a mixture of alkoxysilane and zirconium alkoxide, the toughness, heat resistance, etc. of the resulting moisture-proof film for building materials can be improved. In addition, deterioration of the retort resistance, etc. of the moisture-proof film for building materials during stretching can be avoided. Furthermore, when an alkoxysilane and titanium alkoxide are mixed, the thermal conductivity of the coating film is reduced, and the heat resistance is improved significantly.

[0044] As the polyvinyl alcohol resin, generally, a resin obtained by saponifying polyvinyl acetate can be used. The polyvinyl alcohol resin may be a partially saponified polyvinyl alcohol resin in which several tens of percent of acetate groups remain, a fully saponified polyvinyl alcohol in which no acetate groups remain, or a modified polyvinyl alcohol resin in which OH groups have been modified, and is not particularly limited.

[0045] Examples of the pigment include inorganic pigments such as carbon black, iron black, titanium oxide, antimony white, yellow lead, titanium yellow, red iron oxide, cadmium red, ultramarine blue, and cobalt blue; and organic pigments such as quinacridone red, isoindolinone yellow, and phthalocyanine blue. The colorant may be used alone or in combination of two or more. Among these, titanium oxide is preferable because its particle size can be changed relatively freely, it is chemically inactive, and it has an extremely high refractive index and thus a high hiding power.

[0046] From the viewpoint of hiding power, the barrier coat layer preferably contains 15% by mass or more and 65% by mass or less of a pigment based on the total mass of the barrier coat layer. When the pigment is a black pigment, the content of the pigment is more preferably 15% by mass or more and 30% by mass or less relative to the total mass of the barrier coat layer. Furthermore, when the pigment is a white pigment, the pigment content is more preferably 45% by mass or more and 60% by mass or less relative to the total mass of the barrier coat layer.

[0047] The barrier coat layer may contain a silane coupling agent. For example, a silane coupling agent having a reactive group such as an alkoxy group, such as a methoxy group or an ethoxy group, an acetoxy group, an amino group, or an epoxy group can be used.

[0048] The barrier coat layer can be produced by the following method: First, the above metal alkoxide, the above polyvinyl alcohol-based resin, a pigment, and optionally a silane coupling agent, a sol-gel catalyst, an acid, water, an organic solvent, and the like are mixed to prepare a composition for the barrier coat layer.

[0049] Next, a composition for a barrier coat layer is applied onto the above-mentioned vapor-deposited film by a conventional method, and then dried. This drying step further advances polycondensation of the metal alkoxide, the silane coupling agent, the polyvinyl alcohol resin, etc., to form a coating film. The above coating operation may be further repeated on the first coating film to form a plurality of coating films consisting of two or more layers.

[0050] Next, the substrate film coated with the composition for a barrier coat layer is heat-treated at a temperature of 20°C to 180°C and below the melting point of the deposited film, preferably at a temperature in the range of 50°C to 160°C, for 10 seconds to 10 minutes. This makes it possible to form one or more barrier coat layers on the inorganic layer by coating the composition for the barrier coat layer.

[0051] The method for applying the barrier coat layer composition may be, for example, a coating means such as roll coating using a gravure roll coater or the like, spray coating, spin coating, dipping, brush coating, bar coating, applicator, or the like. By applying the composition once or multiple times, a coating film having a dry thickness of about 0.01 to 30 μm, preferably about 0.1 to 10 μm, can be formed. Further, the composition is heated and dried under normal conditions at a temperature of 50 to 300° C., preferably 70 to 200° C., for 0.005 to 60 minutes, preferably 0.01 to 10 minutes, to cause condensation and form a barrier coat layer.

[0052] From the viewpoint of providing suitable hiding properties, the barrier coat layer preferably has a thickness of 0.1 μm or more and 3.0 μm or less. When the barrier coat layer is a multi-layered layer, the total thickness is preferably within the above range. The barrier coat layer more preferably has a thickness of 0.1 μm or more and 1.0 μm or less.

[0053] (Primer layer) The moisture-proof film for building materials of the present disclosure may include a primer layer.

[0054] The primer layer can be formed using, for example, ester-based resins, urethane-based resins, acrylic-based resins, polycarbonate-based resins, vinyl chloride-vinyl acetate copolymers, polyvinyl butyral-based resins, nitrocellulose-based resins, etc., and one or more of these resins can be used. Among these, it is particularly preferable to form a two-liquid curing type urethane resin layer that is made of a mixed resin of a urethane resin and a nitrocellulose-based resin as a base resin and an isocyanate compound as a curing agent.

[0055] The thickness of the primer layer is preferably from 0.1 μm to 3 μm, and more preferably from 0.2 μm to 1 μm.

[0056] The primer layer can be formed by using a coating method such as roll coating or gravure printing.

[0057] The primer layer has excellent adhesion to the wood-based substrate, and is therefore preferably provided on the side of the barrier coat layer opposite the side on which the inorganic layer is provided. The primer layer may be provided between each layer constituting the moisture-proof film for building materials of the present disclosure. The primer layer may be one layer or two or more layers. The two or more primer layers may have the same composition or different compositions.

[0058] (Method of manufacturing moisture-proof film for building materials) Each layer constituting the moisture-proof film for building materials of the present disclosure can be formed by the method described above. The order in which the layers constituting the moisture-proof film for building materials of the present disclosure are formed is not particularly important.

[0059] <Decorative board> The decorative board of the present disclosure comprises, at least in this order, a moisture-proof film for building materials, a wood-based substrate, and a decorative sheet.

[0060] FIG. 2 is a cross-sectional view for explaining a schematic diagram of a preferred example of the decorative board of the present disclosure. As shown in FIG. 2, the decorative board 20 includes a wood-based substrate 11 and a decorative sheet 12 on the side of the moisture-proof film for building materials 10 on which the barrier coat layer is provided.

[0061] FIG. 3 is a cross-sectional view for explaining a schematic example of a preferred example of the decorative board of the present disclosure. 3, the decorative board 20 includes a moisture-proof film for building materials 10A, a wood-based substrate 11, and a decorative sheet 12. Between the wood-based substrate 11 and the decorative sheet 12, a further moisture-proof film for building materials 10B may be provided.

[0062] (Damp-proof film for building materials) The decorative board of the present disclosure comprises a moisture-proof film for building materials.

[0063] As the moisture-proof film for building materials, the moisture-proof film for building materials of the present disclosure described above is used. The decorative board of the present disclosure may include one layer of the moisture-proof film for building materials, or may include two or more layers. When two or more layers of moisture-proof films for building materials are provided, one of the moisture-proof films for building materials does not have to be the moisture-proof film for building materials of the present disclosure. In this case, from the viewpoint of providing concealment to the surface opposite to the surface on which the decorative sheet of the wood-based substrate is laminated, it is preferable that moisture-proof film for building materials 10A in FIG. 3 be a moisture-proof film for building materials of the present disclosure, and that moisture-proof film for building materials 10B be a moisture-proof film for building materials other than the moisture-proof film for building materials of the present disclosure.

[0064] (wood base material) The decorative board of the present disclosure comprises a wood-based substrate.

[0065] The wood-based substrate is not particularly limited, and any conventionally known substrate can be used. Examples of wood-based substrates include plywood, particle board (PB), medium density fiberboard (MDF), high density fiberboard (HDF), plantation wood, and fast-growing trees.

[0066] (decorative sheet) The decorative board of the present disclosure comprises a decorative sheet.

[0067] The decorative sheet is not particularly limited, and any conventionally known sheet can be used. Examples of the decorative sheet include a decorative sheet made of a paper base material or a synthetic resin base material having at least a wood grain pattern printed thereon.

[0068] (adhesive layer) The decorative board of the present disclosure may include an adhesive layer.

[0069] The adhesive layer is preferably provided between each of the layers constituting the decorative board.

[0070] The adhesive layer is not particularly limited, and any adhesive known in the art for use in building materials can be used. Examples of adhesives include one-component or two-component curable or non-curable vinyl, (meth)acrylic, polyamide, polyester, polyether, polyurethane, epoxy, rubber, and other solvent-based, water-based, or emulsion-based laminating adhesives.

[0071] From the viewpoint of hiding power, the adhesive layer preferably contains a pigment.

[0072] As the pigment, any of those described above for the barrier coat layer can be appropriately selected.

[0073] From the viewpoint of hiding power, the adhesive layer preferably contains 15% by mass or more and 65% by mass or less of a pigment based on the total mass of the adhesive layer. When the pigment is a black pigment, the content of the pigment is more preferably 15% by mass or more and 30% by mass or less relative to the total mass of the adhesive layer. Furthermore, when the pigment is a white pigment, the pigment content is more preferably 45% by mass or more and 60% by mass or less relative to the total mass of the adhesive layer.

[0074] The adhesive can be applied by, for example, a direct gravure roll coating method, a gravure roll coating method, a kiss coating method, a reverse roll coating method, a Fountain method, a transfer roll coating method, or other methods. The amount of application is 0.1 g / m 2 ~10g / m 2 (dry state) is preferable, and 1g / m 2 ~5g / m 2 (Dry state) is more preferable.

[0075] (Manufacturing method of decorative panels) The method for producing the decorative board of the present disclosure is not particularly limited, and for example, a moisture-proof film for building materials, a wood-based substrate, and a decorative sheet may be laminated together with an adhesive layer interposed therebetween.

[0076] The present specification discloses the following:

[0077] The present disclosure (1) is a moisture-proof film for building materials, comprising at least a resin substrate, an inorganic layer, and a barrier coat layer, in this order, the barrier coat layer including a polyvinyl alcohol-based resin and a pigment. The present disclosure (2) is the moisture-proof film for building materials according to the present disclosure (1), wherein the barrier coat layer contains the pigment in an amount of 15% by mass or more and 65% by mass or less based on the total mass of the barrier coat layer. The present disclosure (3) is the moisture-proof film for building materials according to the present disclosure (1) or (2), in which the barrier coat layer has a thickness of 0.1 μm or more and 3.0 μm or less. The present disclosure (4) is the moisture-proof film for building materials according to any one of the present disclosures (1) to (3), wherein the resin substrate has a thickness of 10 μm or more and 100 μm or less. The present disclosure (5) is the moisture-proof film for building materials according to any one of the present disclosures (1) to (4), wherein the resin substrate contains a biomass-derived component. The present disclosure (6) is the moisture-proof film for building materials according to the present disclosure (5), wherein the resin substrate contains 5% by mass or more and 45% by mass or less of ethylene glycol derived from biomass, based on the total mass of the resin substrate. The present disclosure (7) is a decorative board comprising, at least in this order, a wood-based substrate and a decorative sheet on the barrier coat layer side of the moisture-proof film for building materials described in any one of the present disclosures (1) to (6). The present disclosure (8) is the decorative board according to the present disclosure (7), in which the moisture-proof film for materials and the wood-based base material are laminated via an adhesive layer, and the adhesive layer contains a pigment. EXAMPLES

[0078] Next, the present disclosure will be described in more detail by way of examples, but the present disclosure is not limited to these examples.

[0079] <Production of moisture-proof film for building materials> (First moisture-proof film) An aluminum oxide (alumina) film having a thickness of 10 nm was formed by vacuum deposition on one side of a 12 μm-thick PET film (PET-F, manufactured by Unitika Ltd.) serving as a resin substrate. Here, a hydrolysis liquid having a solid content of 4 mass % that was previously prepared and was composed of tetraethoxysilane (ethyl silicate 40), hydrochloric acid, isopropyl alcohol, and ion-exchanged water was stirred. Further, a previously prepared mixture of an aqueous polyvinyl alcohol solution, isopropyl alcohol, and ion-exchanged water was added and stirred to obtain a colorless and transparent composition for a barrier coat layer. Next, the above-mentioned composition for a barrier coat layer was coated on the vapor-deposited film (alumina film) of the PET film by gravure roll coating, dried by heating, and cured to form a barrier coat layer having a thickness of 200 nm. Furthermore, a two-liquid curing type urethane resin composition obtained by adding isocyanate as a curing agent to a urethane / nitrocellulose resin was applied onto the barrier coat layer by gravure printing to form a primer layer A having a thickness of 1 μm. In addition, the surface of the PET film opposite the vapor-deposited film layer was subjected to a corona discharge treatment, and then a two-component curing urethane resin composition made of a urethane / nitrocellulose-based resin to which isocyanate was added as a curing agent was applied to form a 1 μm-thick primer layer B, thereby obtaining a first moisture-proof film (layer structure: primer layer B / resin substrate / vapor-deposited film / barrier coat layer / primer layer A).

[0080] (Second moisture-proof film) An aluminum oxide (alumina) film having a thickness of 10 nm was formed by vacuum deposition on one side of a 12 μm-thick PET film (PET-F, manufactured by Unitika Ltd.) serving as a resin substrate. Here, a hydrolysis liquid having a solid content of 4 mass % that was previously prepared and was composed of tetraethoxysilane (ethyl silicate 40), hydrochloric acid, isopropyl alcohol, and ion-exchanged water was stirred. Further, a previously prepared mixture of an aqueous polyvinyl alcohol solution, isopropyl alcohol, and ion-exchanged water was added and stirred, followed by adding titanium oxide (solid content: 50% by mass) to obtain a white, transparent composition for a barrier coat layer. Next, the above-mentioned composition for a barrier coat layer was coated on the vapor deposition film (alumina film) of the PET film by gravure roll coating, dried by heating, and cured to form a colored barrier coat layer having a thickness of 200 nm. Finally, a two-component curing urethane resin composition, consisting of a urethane / nitrocellulose-based resin as the main agent and an isocyanate as the curing agent, was applied by gravure printing to form a primer layer 1 μm thick to obtain a second moisture-proof film (layer structure: resin substrate / vapor deposition film / colored barrier coat layer / primer layer).

[0081] Example 1 The first and second moisture-proof films thus prepared were adhered to the front and back surfaces of a 2.5 mm-thick medium-density fiberboard (MDF; wood-based substrate) via a water-soluble emulsion adhesive (adhesive layer, thickness 6 μm). When adhering the first moisture-proof film to the wood-based substrate, the primer layer A side of the first moisture-proof film was in contact with the wood-based substrate, and when adhering the second moisture-proof film to the wood-based substrate, the primer layer side of the second moisture-proof film was in contact with the wood-based substrate. Furthermore, a decorative sheet was adhered to the primer layer B side of the first moisture-proof film via a water-soluble emulsion adhesive (adhesive layer, thickness 6 μm) to obtain a decorative board. The side of the decorative board on which the decorative sheet is laminated is referred to as the front side, and the side opposite to the side on which the decorative sheet is laminated is also referred to as the back side. The water-soluble emulsion adhesive used was as follows: Base material: "BA-10L" manufactured by Japan Coating Resin Co., Ltd., modified ethylene vinyl acetate type, Hardener: "BA-11B" manufactured by Japan Coating Resin, isocyanate type (composition ratio) Base agent: Hardener = 100:2.5 (mass ratio)

[0082] Example 2 A decorative board was obtained in the same manner as in Example 1, except that the adhesive used to bond the second moisture-proof film to the wood-based substrate was changed to a colored water-soluble emulsion-based adhesive (adhesive layer, thickness 6 μm). The following colored water-soluble emulsion adhesives were used: Base material: "BA-10L" manufactured by Japan Coating Resin Co., Ltd., modified ethylene vinyl acetate type, Hardener: "BA-11B" manufactured by Japan Coating Resin, isocyanate type Pigment: Titanium dioxide (composition ratio) Base agent: hardener: pigment = 100:2.5:50 (mass ratio)

[0083] Comparative Example 1 A decorative board was produced in the same manner as in Example 1, except that the first moisture-proof film was used instead of the second moisture-proof film. When adhering to a wood-based substrate, the primer layer A side of the first moisture-proof film was in contact with the wood-based substrate on the front side, and the primer layer A side of the first moisture-proof film was in contact with the wood-based substrate on the back side. Thereafter, a white decorative sheet was adhered to the primer layer B side of the first moisture-proof film on the back surface side via a water-soluble emulsion adhesive (adhesive layer, thickness 6 μm). The side of the decorative board on which the white decorative sheet is laminated is also referred to as the back side.

[0084] Comparative Example 2 A decorative board was produced in the same manner as in Example 1, except that the first moisture-proof film was used instead of the second moisture-proof film. When adhering to a wood-based substrate, the primer layer A side of the first moisture-proof film was in contact with the wood-based substrate on the front side, and the primer layer A side of the first moisture-proof film was in contact with the wood-based substrate on the back side.

[0085] Example 3 A decorative board was produced in the same manner as in Example 1, except that in the first moisture-proof film, the resin substrate was changed to a 12 μm-thick PET film containing 20 mass % of biomass-derived ethylene glycol based on the total mass of the resin substrate.

[0086] Example 4 A decorative board was produced in the same manner as in Example 2, except that in the second moisture-proof film, the resin substrate was changed to a 12 μm-thick PET film containing 20 mass % of biomass-derived ethylene glycol based on the total mass of the resin substrate.

[0087] <Concealment> A light source (Toshiba, FLR40SD-EDL-D65 / M) was applied to the back side of the prepared decorative board from a position at 90°, and visual inspection was performed from a distance of about 1 m, and evaluation was performed according to the following criteria. The results are shown in Table 1. ++:Cannot see the color of MDF +: The color of the MDF can be seen slightly (no visible problems with appearance) -: You can check the color of the MDF

[0088] [Table 1]

[0089] As shown in Table 1, it was confirmed that Examples 1 to 4 had excellent hiding power. In addition, it was confirmed that the number of steps could be reduced in comparison with Comparative Example 1 in which a decorative sheet was laminated on the back surface side. The number of steps means the number of steps for laminating moisture-proof films for building materials or decorative sheets when producing a decorative board. [Explanation of symbols]

[0090] 1 Resin substrate 2 Inorganic layer 3 Barrier Coat Layer 4 Primer layer 10, 10A, 10B Moisture-proof film for building materials 11 Wood base material 12 Decorative Sheet 20 Decorative Panel

Claims

1. The film comprises a resin substrate, an inorganic layer, and a barrier coat layer, at least in this order; The barrier coat layer contains a polyvinyl alcohol resin and a pigment. Moisture-proof film for building materials.

2. The moisture-proof film for building materials according to claim 1 , wherein the barrier coat layer contains the pigment in an amount of 15% by mass or more and 65% by mass or less based on the total mass of the barrier coat layer.

3. 3. The moisture-proof film for building materials according to claim 1, wherein the barrier coat layer has a thickness of 0.1 μm or more and 3.0 μm or less.

4. 3. The moisture-proof film for building materials according to claim 1, wherein the resin substrate has a thickness of 10 μm or more and 100 μm or less.

5. The moisture-proof film for building materials according to claim 1 or 2, wherein the resin substrate contains a biomass-derived component.

6. The moisture-proof film for building materials according to claim 5 , wherein the resin substrate contains 5% by mass or more and 45% by mass or less of ethylene glycol derived from biomass, based on the total mass of the resin substrate.

7. A decorative board comprising, at least in this order, a wood-based substrate and a decorative sheet on the barrier coat layer side of the moisture-proof film for building materials according to claim 1 or 2.

8. The decorative board according to claim 7 , wherein the moisture-proof film for building materials and the wood-based substrate are laminated via an adhesive layer, and the adhesive layer contains a pigment.

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