Moisture-proof decorative paper

Abstract

The purpose of the present application is to provide a moisture-proof decorative paper that has high moisture-proofing performance, whereby it is possible to prevent warpage of a decorative sheet even when used in a location where there is a large difference in temperature and humidity environments on both sides, and that addresses environmental concerns by reducing the amount of plastic used. A moisture-proof decorative paper (100) according to the present embodiment comprises a moisture-proof layer (10) and a decorative layer (20) in that order on one surface of a paper base material (11). The moisture-proof layer (10) is a laminate having a structure in which a first resin layer (12), an aluminum vapor-deposited layer (13), and a second resin layer (14) are laminated in that order from the paper base material (11) side. The thickness of the aluminum vapor-deposited layer (13) is 60 nm or more. The decorative layer (20) includes a printed layer (15) and a protective resin layer (16) in that order from the moisture-proof layer (10) side.

Description

Moisture-proof decorative paper

[0001] The present invention relates to a moisture-proof decorative paper used for fittings such as interior doors, kitchen doors, storage doors, and sliding doors, and more particularly to a moisture-proof decorative paper that is pasted onto the surface of decorative boards to prevent warping of the boards caused by changes in humidity, temperature, etc.

[0002] Traditionally, interior doors, kitchen doors, storage doors, and other fixtures have been known to gradually warp during use due to humidity and temperature fluctuations. This phenomenon occurs primarily due to uneven moisture content distribution within the wooden fixture caused by humidity and temperature differences between indoors and outdoors. Humidity differences create differences in moisture absorption and release on the front and back surfaces of the wooden fixture, resulting in expansion due to high moisture content on the higher humidity side and contraction due to low moisture content on the lower humidity side, resulting in warping. Furthermore, temperature differences cause moisture to migrate to the colder side of the wood substrate, creating a moisture content gradient across the thickness, resulting in warping. Typically, the lower temperature side is often the most humid and has a high moisture content. In such cases, these two effects act in the same direction, making warping most pronounced.

[0003] A widely used method for preventing such warping of wooden fixtures is to use moisture-proof sheets with low moisture permeability in the fixture components, thereby reducing the amount of moisture absorbed and released by the components. Patent Document 1 also proposes adhering a moisture-proof decorative sheet having a five-layer structure consisting of a protective resin layer / printed pattern layer / interleaf reinforced paper / synthetic resin layer / interleaf reinforced paper from the front side to the surface of a board substrate such as plywood, using an adhesive, and adhering a moisture-proof back sheet having a three-layer structure consisting of interleaf reinforced paper / synthetic resin / interleaf reinforced paper to the back side of the board substrate, using an adhesive, to form a moisture-proof decorative board, which is then adhered to the front and back of a flush door, respectively, using an adhesive. The moisture permeability of the moisture-proof sheet in this case is 5 (g / m ２ ・24hr) or more 30(g / m ２ ・24 hours or less is considered good.

[0004] Furthermore, when even higher moisture resistance is required, a method for preventing deformation of the decorative board is known in which a moisture-proof sheet with a vapor-deposited layer is attached to a synthetic resin substrate. Since a vapor-deposited layer must be provided on a smooth surface to achieve high moisture resistance, a synthetic resin substrate is generally selected, and it is considered technically difficult to achieve high moisture resistance using a paper substrate.

[0005] On the other hand, however, in recent years, growing environmental awareness stemming from the problem of marine plastic waste and the like has led to a growing trend toward a plastic-free society. From the perspective of reducing the amount of plastic material used, the use of paper instead of plastic materials has been considered in various fields. Furthermore, from the perspective of effective resource utilization under the Resource Effective Utilization Promotion Act, there is a demand to increase the proportion of paper in the overall laminate having barrier properties. For example, Patent Document 2 listed below discloses a base paper for metallized paper, which has a specific clay coat layer and a resin layer, in that order, on at least one side of a specific paper substrate, for forming a metallized layer by vapor deposition.

[0006] Patent No. 3206408 Patent No. 6958755

[0007] Conventional moisture-proof sheets sometimes lack sufficient moisture resistance, and when used for long periods on doors, sliding doors, partitions, and other surfaces with large differences in temperature and humidity, the degree of expansion and contraction on both sides can differ, causing warping of the decorative panels. Furthermore, all of these sheets are primarily made from plastic, and there is a demand for reducing their use to reduce environmental impact.

[0008] The present inventors have investigated various laminates comprising a paper substrate, a first resin layer, an aluminum vapor-deposited layer, and a second resin layer as laminates with excellent environmental compatibility. They have found that such laminates have a high water vapor permeability and are unstable. In other words, the present inventors have newly discovered a problem in that some of the above-mentioned laminates according to conventional techniques have low and unstable water vapor barrier properties (i.e., some have uneven water vapor barrier performance and have low yields).

[0009] The present invention has been made to solve this problem, and aims to provide an environmentally friendly moisture-proof decorative paper that has high moisture-proof performance, can prevent warping of the decorative board even when used in a place where there is a large difference in temperature and humidity environment on both sides, and reduces the amount of plastic used.

[0010] The present inventors speculate as follows why conventional laminates have high and unstable water vapor permeability and why the laminate according to the present disclosure has high and stable water vapor barrier properties (i.e., low and stable water vapor permeability).

[0011] Compared to plastic films, paper experiences greater dimensional changes due to moisture absorption and release. Meanwhile, the moisture content of paper varies depending on the production lot. Furthermore, the moisture content of paper changes depending on the environmental conditions during the production, storage, and use of moisture-proof decorative paper. In paper made continuously on a paper machine, the fibers are oriented in the machine direction (MD) of the paper machine, resulting in greater expansion and contraction in the cross direction (CD). Therefore, the aluminum vapor-deposited layer cannot keep up with the dimensional changes of the paper due to changes in moisture content, resulting in defects parallel to the MD. The defects impair the continuity of the aluminum vapor-deposited layer, increasing the water vapor permeability of the laminate.

[0012] The second resin layer is formed, for example, by wet-coating a mixture of a resin and a solvent onto the aluminum vapor-deposited layer to form a coating film and then drying the coating film. Here, as the coating film dries, the solvent volatilizes and the second resin layer is formed. If the formation of the surface layer of the second resin layer proceeds without the solvent being completely volatilized, the solvent contained in the second resin layer may bump. Such bumping of the solvent may cause micro-sized defects in the second resin layer. Furthermore, due to differences in the thermal shrinkage behavior between the paper substrate and the second resin layer, similar defects may occur in the second resin layer when the coating film for forming the second resin layer is dried. These defects in the second resin layer may reach the aluminum vapor-deposited layer. Such defects in the aluminum vapor-deposited layer can cause unstable water vapor barrier properties.

[0013] However, by making the thickness of the aluminum vapor-deposited layer 60 nm or more, it is possible to suppress the occurrence of defects caused by moisture absorption and desorption of the paper and the occurrence of defects caused by bumping of the solvent contained within the second resin layer, and as a result, the laminate has high and stable water vapor barrier properties.

[0014] According to the present disclosure, it is possible to provide a moisture-proof decorative paper that is a laminate with high and stable water vapor barrier properties and has a high paper component ratio. Furthermore, according to one aspect of the present invention, it is possible to provide a moisture-proof decorative paper that contributes to reducing the amount of plastic material used. In other words, according to one aspect of the present invention, by providing high moisture-proof performance, it is possible to prevent warping of the decorative board even when used in a place where there is a large difference in temperature and humidity environment on both sides, and by reducing the amount of plastic used, it is possible to provide an environmentally friendly moisture-proof decorative paper. Problems, configurations, and effects other than those described above will be made clear in the description of the following embodiment of the invention.

[0015] 1 is a schematic cross-sectional view showing an example of the configuration of moisture-proof decorative paper according to an embodiment of the present invention.

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings are schematic, and the relationship between thickness and planar dimensions, the ratio of each thickness, etc., differ from the actual ones. Furthermore, the embodiments shown below are merely examples of configurations that embody the technical concept of the present invention, and the technical concept of the present invention is not limited to the materials, shapes, etc. of the components described below. The technical concept of the present invention can be modified in various ways within the technical scope defined by the claims.

[0017] <Moisture-proof decorative paper 100> Figure 1 is a schematic cross-sectional view showing the configuration of moisture-proof decorative paper 100 according to this embodiment. As shown in Figure 1, the moisture-proof decorative paper 100 according to this embodiment is formed by laminating, in this order, a paper base material 11, a first resin layer 12, an aluminum vapor-deposited layer 13, a second resin layer 14, a printed pattern layer 15, and a protective resin layer 16. The thickness of the aluminum vapor-deposited layer 13 is 60 nm or more. In the moisture-proof decorative paper 100 according to this embodiment, the first resin layer 12, the aluminum vapor-deposited layer 13, and the second resin layer 14 form the moisture-proof layer 10, and the printed pattern layer 15 and the protective resin layer 16 form the decorative layer 20.

[0018] The moisture-proof decorative paper 100 according to this embodiment is a moisture-proof paper that is used, for example, by being attached to the surface of a decorative board used in an interior door panel, although this is not shown in the drawings. The moisture-proof decorative paper 100 is used to prevent warping of the decorative board caused by moisture absorption and release due to changes in indoor temperature and humidity. By using the moisture-proof decorative paper 100, it is possible to provide a moisture-proof paper that addresses the movement to eliminate plastic and the problem of marine litter, has a high proportion of paper components, and has stable and excellent water vapor barrier properties.

[0019] [Moisture permeability (water vapor permeability) of moisture-proof decorative paper 100] The moisture-proof decorative paper 100 has a water vapor permeability of 5 g / (m) at a temperature of 40°C and a relative humidity (RH) of 90%. ２ ・24hr) or less, 4g / (m ２ ・24hr) or less, 3g / (m ２ ・24hr) or less, 2g / (m ２ 24 hr) or less, or 1 g / (m ２ The water vapor transmission rate may be a value measured by the method described in the Examples below.

[0020] <Paper substrate> The paper substrate 11 is not particularly limited and may be appropriately selected depending on the application of the moisture-proof decorative paper 100. Specific examples of the paper substrate 11 include tissue paper, fine paper, art paper, cast-coated paper, kraft paper, titanium paper, linter paper, paperboard, gypsum board paper, coated paper, parchment paper, glassine paper, parchment paper, paraffin paper, and Japanese paper. Preferably, tissue paper (so-called inter-paper reinforced paper) in which a synthetic resin is mixed with paper components (e.g., cellulose fibers) to enhance inter-paper strength, or paper impregnated with latex or synthetic resin, is used.

[0021] The basis weight of the paper base material 11 is not particularly limited, but the basis weight of the paper base material 11 is preferably 20 g / m ２ If the paper substrate 11 has a basis weight of less than 200 g / m, the paper substrate 11 is too soft and wrinkles tend to occur during processing. ２ If the basis weight is more than 20 g / m, peeling from the paper layer is likely to occur. ２ More than 200g / m ２ The following range is preferred: ２ More than 100g / m ２ More preferably, the range is 20 g / m ２ 50g / m or more ２ The following ranges are more preferable: Furthermore, the surface of the paper substrate 11 may be subjected to a surface treatment such as corona treatment, plasma treatment, or flame treatment, as required.

[0022] The paper substrate 11 may have a coating layer (not shown) on at least the side of the paper substrate 11 that contacts the first resin layer 12. When the paper substrate 11 has a coating layer, the paper substrate 11 may have at least a paper layer and a coating layer. The coating layer may be provided on both surfaces (i.e., the front and back surfaces) of the paper substrate 11. The coating layer can prevent the resin constituting the first resin layer 12 from penetrating into the paper layer and also serve as a filler to fill in unevenness in the paper layer, allowing the first resin layer 12 to be formed uniformly and without defects. The coating layer may contain, as a binder resin, various copolymers such as styrene-butadiene, styrene-acrylic, and ethylene-vinyl acetate copolymers, polyvinyl alcohol resins, cellulose resins, paraffin (wax), etc. The coating layer may also contain, as a filler, clay, kaolin, calcium carbonate, talc, mica, etc. The coating layer may be a clay coating layer containing at least clay as a filler.

[0023] The rate of change in the cross-machine direction (CD) dimension of the paper substrate 11 at 40°C and 90% RH (relative humidity) relative to the dimension at 40°C and 20% RH may be 0.3% or more, 0.4% or more, or 0.6% or more, and may be 1.5%, 1.3%, or 1.0% or less. The rate of change in the machine direction (MD) dimension of the paper substrate 11 at 40°C and 90% RH relative to the dimension at 40°C and 20% RH may be 0.05% or more and 0.20% or less. If the rate of change of the paper substrate 11 is within the above numerical range, the aluminum vapor-deposited layer 13 can follow the dimensional changes of the paper that occur with changes in moisture content, making defects parallel to the MD less likely to occur.

[0024] When the paper substrate 11 has a coating layer, the thickness of the coating layer may be 1.5 μm or more and 15 μm or less. The thickness of the coating layer may also be 1.8 μm or more, 3 μm or more, 5 μm or more, or 6 μm or more. Furthermore, the thickness of the coating layer may be 12 μm or less, or 10 μm or less. When the thickness of the coating layer is within the above range, the moisture-proof decorative paper 100 can more stably achieve higher water vapor barrier properties.

[0025] The mass of the paper components contained in the paper base material 11 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 entire moisture-proof decorative paper 100. If the mass of the paper components contained in the paper base material 11 is 50% by mass or more based on the entire moisture-proof decorative paper 100, the amount of plastic material used can be sufficiently reduced, the entire moisture-proof decorative paper 100 can be said to be made of paper, and it has excellent recyclability.

[0026] <First Resin Layer> The first resin layer 12 is provided on the surface of the paper substrate 11 to improve adhesion between the paper substrate 11 and the aluminum vapor-deposited layer 13 described below, and to improve the gas barrier properties (particularly the water vapor barrier properties) of the moisture-proof decorative paper 100. The first resin layer 12 may contain at least one selected from the group consisting of polyolefins having acidic groups, polyvinyl alcohol-based resins, and polyurethane-based resins. From the viewpoint of being able to more stably obtain higher water vapor barrier properties, the first resin layer 12 preferably contains at least one of polyolefins having acidic groups and polyurethane-based resins, and more preferably contains a polyolefin having acidic groups.

[0027] When the first resin layer 12 contains a polyolefin having an acidic group, the first resin layer 12 has excellent flexibility, can suppress cracking of the aluminum vapor-deposited layer 13 that may occur after bending (folding), and can improve adhesion between the first resin layer 12 and the aluminum vapor-deposited layer 13. Furthermore, the inclusion of a polyolefin having an acidic group makes it possible to form a dense film due to the crystallinity of the polyolefin, and exhibits water vapor barrier properties. In other words, with the above-mentioned polyolefin having an acidic group, water vapor barrier properties are exhibited due to the crystallinity of the polyolefin, and the presence of the acidic group exhibits adhesion to the aluminum vapor-deposited layer 13. The polyolefin having an acidic group may have at least one selected from a carboxyl group, a salt of a carboxyl group, a carboxylic anhydride group, and a carboxylic acid ester.

[0028] Examples of polyolefins having acidic groups include copolymers of ethylene or propylene with unsaturated carboxylic acids (unsaturated compounds having a carboxyl group, such as acrylic acid, methacrylic acid, or maleic anhydride), unsaturated carboxylic acid esters, and salts of carboxylic acids neutralized with basic compounds. Other examples include copolymers of ethylene or propylene with vinyl acetate, epoxy compounds, chlorine compounds, urethane compounds, polyamide compounds, and the like. The first resin layer 12 preferably contains an ethylene-unsaturated carboxylic acid copolymer, as this provides more stable water vapor barrier properties. Specific examples of polyolefins having acidic groups include copolymers of acrylic acid esters and maleic anhydride, ethylene-vinyl acetate copolymers, and ethylene-glycidyl methacrylate copolymers.

[0029] When the first resin layer 12 contains a polyvinyl alcohol-based resin, the polyvinyl alcohol-based resin has hydroxyl groups that readily bond with metals such as aluminum in the aluminum vapor-deposited layer 13, thereby making it possible to improve adhesion between the aluminum vapor-deposited layer 13 and the first resin layer 12. Furthermore, such a first resin layer 12 has excellent flexibility and can suppress cracking of the aluminum vapor-deposited layer 13 that may occur after bending (folding). The polyvinyl alcohol-based resin is a resin that contains vinyl alcohol as a constituent unit, and examples of the polyvinyl alcohol-based resin include fully saponified polyvinyl alcohol resins, partially saponified polyvinyl alcohol resins, modified polyvinyl alcohol resins, and ethylene-vinyl alcohol copolymer resins.

[0030] Polyurethane resins are obtained by bonding the acid groups of an acid group-containing polyurethane with the amino groups of a polyamine used as a crosslinker. That is, polyurethane resins can be said to be a reaction product of an acid group-containing polyurethane and a polyamine, or to be formed by crosslinking an acid group-containing polyurethane with a polyamine. The bond between the acid groups of the acid group-containing polyurethane and the amino groups of the polyamine may be an ionic bond (e.g., an ionic bond between a carboxyl group and a tertiary amino group) or a covalent bond (e.g., an amide bond).

[0031] The acid group-containing polyurethane constituting the polyurethane-based resin has anionic properties and self-emulsifying properties due to the presence of acid groups, and is also referred to as anionic self-emulsifying polyurethane. The acid groups of the acid group-containing polyurethane can bond with the amino groups (primary amino groups, secondary amino groups, tertiary amino groups, etc.) of the polyamine constituting the polyurethane-based resin. Examples of the acid groups include carboxyl groups and sulfonic acid groups. The acid groups can usually be neutralized with a neutralizing agent (base) and may form a salt with the base. The acid groups may be located at the terminal or side chain of the acid group-containing polyurethane, but are preferably located at least on the side chain.

[0032] The acid value of the acid group-containing polyurethane can be selected within a range that ensures water dispersibility, and can be 5 to 100 mgKOH / g, or alternatively 10 to 70 mgKOH / g, or even 15 to 60 mgKOH / g. When the acid value of the acid group-containing polyurethane is at or above the lower limit of the above range (5 mgKOH / g), water dispersibility of the acid group-containing polyurethane is easily achieved, and uniform dispersion of the polyurethane resin with other materials and dispersion stability of the coating agent are easily ensured. When the acid value of the acid group-containing polyurethane is at or below the upper limit of the above range (100 mgKOH / g), water resistance and gas barrier properties of the first resin layer 12 are easily ensured. The acid value of the acid group-containing polyurethane is measured by a method in accordance with JIS K 0070.

[0033] From the viewpoint of gas barrier properties, the total concentration of urethane groups and urea groups in the acid group-containing polyurethane can be 15% by mass or more, and may be 20 to 60% by mass of the entire acid group-containing polyurethane. When the total concentration of urethane groups and urea groups is equal to or greater than the lower limit (15% by mass) of the above range, the gas barrier properties of the first resin layer 12 tend to be good. When the total concentration of urethane groups and urea groups is equal to or less than the upper limit (60% by mass) of the above range, the first resin layer 12 tends to be prevented from becoming rigid and brittle.

[0034] The urethane group concentration refers to the ratio of the molecular weight of the urethane group (59 g / equivalent) to the molecular weight of the constituent units of the polyurethane resin. The urea group concentration refers to the ratio of the molecular weight of the urea group (primary amino group (amino group): 58 g / equivalent, secondary amino group (imino group): 57 g / equivalent) to the molecular weight of the constituent units of the polyurethane resin. When a mixture of two or more types of acid group-containing polyurethane is used, the urethane group concentration and urea group concentration can be calculated based on the charged base of the reaction components, i.e., the use ratio of each component.

[0035] The acid group-containing polyurethane may have at least rigid units (units composed of hydrocarbon rings) and short-chain units (e.g., units composed of hydrocarbon chains). The constituent units of the acid group-containing polyurethane may contain a hydrocarbon ring (at least one of an aromatic and a non-aromatic hydrocarbon ring) derived from a polyisocyanate component, a polyhydroxy acid component, a polyol component, or a chain extender component (particularly, at least the polyisocyanate component).

[0036] The proportion of hydrocarbon ring units in the structural units of the acid group-containing polyurethane can be 10 to 70 mass %, alternatively 15 to 65 mass %, or alternatively 20 to 60 mass %, relative to the total of all structural units. When the proportion of hydrocarbon ring units is equal to or greater than the lower limit of the above range (10 mass %), the gas barrier properties of the first resin layer 12 are likely to be improved. When the proportion of hydrocarbon ring units is equal to or less than the upper limit of the above range (70 mass %), the first resin layer 12 is likely to be prevented from becoming rigid and brittle.

[0037] The number average molecular weight of the acid group-containing polyurethane can be selected appropriately, but can be 800 to 1,000,000, or alternatively 800 to 200,000, or 800 to 100,000. When the number average molecular weight of the acid group-containing polyurethane is equal to or less than the upper limit (1,000,000) of the above range, the coating agent is likely to have an appropriate viscosity. When the number average molecular weight of the acid group-containing polyurethane is equal to or greater than the lower limit (800) of the above range, the first resin layer 12 is likely to have good gas barrier properties. The number average molecular weight of the acid group-containing polyurethane is a value measured by gel permeation chromatography (GPC) in terms of standard polystyrene.

[0038] The acid group-containing polyurethane may be crystalline to enhance gas barrier properties. The glass transition temperature of the acid group-containing polyurethane may be 100°C or higher, or may be 110°C or higher, or may be 120°C or higher. When the glass transition temperature of the acid group-containing polyurethane is 100°C or higher, the gas barrier properties of the first resin layer 12 tend to be good. The glass transition temperature of the acid group-containing polyurethane may be 200°C or lower, or may be 180°C or lower, or may be 150°C or lower. Therefore, the glass transition temperature of the acid group-containing polyurethane may be 100 to 200°C, or may be 110 to 180°C, or may be 120 to 150°C. The glass transition temperature of the acid group-containing polyurethane is measured by differential scanning calorimetry (DSC).

[0039] The polyamine constituting the polyurethane resin is a compound having two or more basic nitrogen atoms. The basic nitrogen atom is a nitrogen atom that can bond with the acid group of the acid group-containing polyurethane, and examples thereof include nitrogen atoms in amino groups such as primary amino groups, secondary amino groups, and tertiary amino groups. The polyamine is not particularly limited as long as it can bond with the acid group of the acid group-containing polyurethane and improve the gas barrier property, and various compounds having two or more basic nitrogen atoms can be used. The polyamine can be a polyamine having two or more amino groups of at least one type selected from the group consisting of primary amino groups, secondary amino groups, and tertiary amino groups.

[0040] Examples of polyamines include alkylenediamines, polyalkylenepolyamines, and silicon compounds having multiple basic nitrogen atoms. Examples of alkylenediamines include alkylenediamines having 2 to 10 carbon atoms, such as ethylenediamine, 1,2-propylenediamine, 1,3-propylenediamine, 1,4-butanediamine, and 1,6-hexamethylenediamine. Examples of polyalkylenepolyamines include tetraalkylenepolyamine. Examples of silicon compounds having multiple basic nitrogen atoms (including nitrogen atoms such as amino groups) include silane coupling agents having multiple basic nitrogen atoms, such as 2-[N-(2-aminoethyl)amino]ethyltrimethoxysilane and 3-[N-(2-aminoethyl)amino]propyltriethoxysilane.

[0041] The amine value of the polyamine can be 100 to 1900 mgKOH / g, or alternatively, 150 to 1900 mgKOH / g, 200 to 1900 mgKOH / g, 200 to 1700 mgKOH / g, or 300 to 1500 mgKOH / g. When the amine value of the polyamine is equal to or greater than the lower limit of the above range (100 mgKOH / g), the gas barrier properties of the first resin layer 12 are likely to be improved. When the amine value of the polyamine is equal to or less than the upper limit of the above range (1900 mgKOH / g), the aqueous dispersion stability of the polyurethane resin is likely to be improved.

[0042] [Method for Measuring Amine Value] The amine value of polyamines is measured by the following method. 0.5 to 2 g of sample is weighed out accurately (sample amount: S g). 30 g of ethanol is added to the weighed sample to dissolve it. Bromophenol blue is added to the resulting solution as an indicator, and titration is carried out with a 0.2 mol / L ethanolic hydrochloric acid solution (potency: f). The point at which the color of the solution changes from green to yellow is set as the endpoint, and the titration volume (A mL) at this point is used to calculate the amine value using the following formula 1. Formula 1: Amine value = A × f × 0.2 × 56.108 / S [mg KOH / g]

[0043] In forming the polyurethane resin, the molar ratio of the acid groups of the acid group-containing polyurethane to the basic nitrogen atoms of the polyamine (acid groups / basic nitrogen atoms) can be 10 / 1 to 0.1 / 1, and may be 5 / 1 to 0.2 / 1. As the polyurethane resin, a commercially available polyurethane resin may be used, or a polyurethane resin produced by a known production method may be used.

[0044] Methods for producing polyurethane resins are not particularly limited, and include conventional aqueous polyurethane resin technologies such as the acetone method and the prepolymer method. In the urethanization reaction, urethanization catalysts such as amine catalysts, tin catalysts, and lead catalysts may be used as needed. For example, acid group-containing polyurethanes can be prepared by reacting a polyisocyanate compound with a polyhydroxy acid and, optionally, at least one of a polyol component and a chain extender component in an inert organic solvent such as a ketone such as acetone, an ether such as tetrahydrofuran, or a nitrile such as acetonitrile. More specifically, a polyisocyanate compound, a polyhydroxy acid, and a polyol component are reacted in an inert organic solvent (particularly a hydrophilic or water-soluble organic solvent) to produce a prepolymer having an isocyanate group at its terminal. The resulting prepolymer is then neutralized with a neutralizing agent and dissolved or dispersed in an aqueous medium. A chain extender component is then added and reacted, and the organic solvent is removed to produce an aqueous dispersion of the acid group-containing polyurethane. A polyurethane resin in the form of an aqueous dispersion can be prepared by adding a polyamine to the aqueous dispersion of the acid group-containing polyurethane obtained in this manner and heating it as needed. When heating, the heating temperature can be 30 to 60°C.

[0045] The first resin layer 12 may contain other components in addition to the above-described polyolefins having acidic groups, polyvinyl alcohol-based resins, and polyurethane-based resins. Examples of other components include polyolefins other than the above-described polyolefins having acidic groups, silane coupling agents, organic titanates, polyacrylics, polyesters, polyurethanes, polycarbonates, polyureas, polyamides, polyimides, melamine, and phenols. The content of at least one selected from the group consisting of polyolefins having acidic groups, polyvinyl alcohol-based resins, and polyurethane-based resins in the first resin layer 12 may be, for example, 50% by mass or more, 70% by mass or more, 90% by mass or more, or 100% by mass of the entire first resin layer 12.

[0046] The thickness of the first resin layer 12 may be, for example, 0.5 μm or more, 1 μm or more, 2 μm or more, 20 μm or less, 10 μm or less, or 5 μm or less. If the thickness of the first resin layer 12 is 0.5 μm or more, the unevenness of the paper base material 11 described above can be efficiently filled, and the aluminum vapor deposition layer 13 described below can be laminated uniformly. Furthermore, if the thickness of the first resin layer 12 is 20 μm or less, the aluminum vapor deposition layer 13 can be laminated uniformly while keeping costs down.

[0047] Examples of solvents contained in the coating liquid for forming the first resin layer 12 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. Among these, from the viewpoint of properties, methyl alcohol, ethyl alcohol, isopropyl alcohol, toluene, ethyl acetate, methyl ethyl ketone, and water are preferred. Furthermore, from the viewpoint of the environment, methyl alcohol, ethyl alcohol, isopropyl alcohol, and water are preferred.

[0048] A method for providing the first resin layer 12 includes applying a coating liquid containing the above-mentioned polyolefin, polyvinyl alcohol-based resin, or polyurethane-based resin having an acidic group and a solvent, etc., onto the paper substrate 11 to form a coating film, and then drying the coating film.

[0049] <Aluminum vapor-deposited layer> The aluminum vapor-deposited layer 13 is a layer formed by vapor-depositing aluminum or an aluminum compound. The aluminum vapor-deposited layer 13 may be obtained by vapor-depositing aluminum, or may contain aluminum oxide (AlOx), silicon oxide (SiOx), or the like. The thickness of the aluminum vapor-deposited layer 13 is 60 nm or more, and may be greater than 60 nm, greater than 70 nm, 80 nm or more, or 90 nm or more. The thickness of the aluminum vapor-deposited layer 13 may be 300 nm or less, 200 nm or less, or 100 nm or less. The thickness of the aluminum vapor-deposited layer 13 is measured by the method in the examples described below.

[0050] <Second Resin Layer> The second resin layer 14 is provided on the surface of the aluminum vapor-deposited layer 13 so as to be in contact with the aluminum vapor-deposited layer 13. The second resin layer 14 may contain a polyolefin having an acidic group. The polyolefin having an acidic group may have at least one selected from a carboxyl group, a salt of a carboxyl group, a carboxylic anhydride group, and a carboxylic acid ester.

[0051] Examples of polyolefins having acidic groups include copolymers of ethylene or propylene with unsaturated carboxylic acids (unsaturated compounds having a carboxyl group, such as acrylic acid or methacrylic acid) or unsaturated carboxylic acid esters, and salts of carboxylic acids neutralized with basic compounds. Other examples include copolymers of vinyl acetate, epoxy compounds, chlorine compounds, urethane compounds, polyamide compounds, etc. Specific examples of polyolefins having acidic groups include copolymers of acrylic acid esters and maleic anhydride, ethylene-unsaturated carboxylic acid copolymers, ethylene-vinyl acetate copolymers, and ethylene-glycidyl methacrylate copolymers.

[0052] By including a polyolefin having an acidic group, the second resin layer 14 has excellent flexibility, can suppress cracking of the aluminum vapor-deposited layer 13 that may occur after bending (folding), and has excellent adhesion to the aluminum vapor-deposited layer 13. Furthermore, by including the above-mentioned polyolefin having an acidic group, it is possible to form a dense film due to the crystallinity of the polyolefin, and water vapor barrier properties are exhibited. Furthermore, the polyolefin has an acidic group, which exhibits adhesion to the aluminum vapor-deposited layer 13.

[0053] The second resin layer 14 preferably contains an ethylene-unsaturated carboxylic acid copolymer, as this provides more stable water vapor barrier properties. The second resin layer 14 may contain other components in addition to the polyolefin having an acidic group. Examples of such other components include silane coupling agents, organic titanates, polyacrylics, polyesters, polyurethanes, polycarbonates, polyureas, polyamides, polyolefin emulsions, polyimides, melamine, and phenols. The content of the polyolefin having an acidic group in the second resin layer 14 may be, for example, 50% by mass or more, 70% by mass or more, 90% by mass or more, or 100% by mass of the entire second resin layer 14.

[0054] The thickness of the second resin layer 14 may be, for example, 0.05 μm or more, 0.5 μm or more, 1 μm or more, 2 μm or more, 20 μm or less, 10 μm or less, or 5 μm or less. If the thickness of the second resin layer 14 is 0.05 μm or more, it can fully fulfill its role as a protective layer for the aluminum vapor deposition layer 13 described above. Furthermore, if the thickness of the second resin layer 14 is 20 μm or less, it can fully fulfill its adhesion and barrier properties with the aluminum vapor deposition layer 13 while suppressing costs. Furthermore, by setting the thickness of the second resin layer 14 to 2 μm or more and 10 μm or less, the aluminum vapor deposition layer 13 becomes less likely to crack, and sufficient water vapor barrier properties and oil resistance can be obtained even after bending.

[0055] Examples of solvents contained in the coating liquid for forming the second resin layer 14 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. Among these, from the viewpoint of properties, methyl alcohol, ethyl alcohol, isopropyl alcohol, toluene, ethyl acetate, methyl ethyl ketone, and water are preferred. Furthermore, from the viewpoint of the environment, methyl alcohol, ethyl alcohol, isopropyl alcohol, and water are preferred.

[0056] A method for providing the second resin layer 14 includes applying a coating liquid containing the above-described polyolefin having acidic groups and a solvent, etc., onto the aluminum vapor-deposited layer 13 to form a coating film, and then drying the coating film. The melting point of the polyolefin having acidic groups in the coating liquid is preferably 70 to 160°C, more preferably 80 to 120°C. When the melting point of the polyolefin having acidic groups is 70°C or higher, blocking tends to be less likely to occur in high-temperature environments. From the perspective of preventing blocking, it is preferable that the particle size of the polyolefin having acidic groups be large so that the contact area is small. Although not particularly limited, the particle size of the polyolefin having acidic groups may specifically be 1 nm or more, 0.1 μm or more, 1 μm or less, 0.7 μm or less, or 0.5 μm or less.

[0057] <Printed Pattern Layer> The printed pattern layer 15 is intended to impart design, and any pattern can be used as the pattern. The pattern of the printed pattern layer 15 can be, for example, 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. Furthermore, by utilizing the brightness of the aluminum vapor deposition layer 13, the printed pattern layer 15 can be provided with a metallic pattern, providing excellent design expression. A solid ink layer can be provided between the printed pattern layer 15 and the second resin layer 14 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.

[0058] There are no particular limitations on the printing ink, and either oil-based or water-based inks are acceptable. The printing ink used for the print pattern layer 15 can be the same as the printing ink used for print pattern layers in conventional decorative papers, and for example, acrylic ink can be used. As the 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.

[0059] <Protective Resin Layer> The protective resin layer 16, which functions as a surface protective layer, is a layer for protecting the surface of the moisture-proof decorative paper 100, and is provided to impart surface properties such as scratch resistance, abrasion resistance, stain resistance, water resistance, and weather resistance required of the moisture-proof decorative paper 100. The formation of the protective resin layer (surface protective layer) 16 is not particularly limited, and it can be formed by a known coating method such as gravure coating.

[0060] The material for the protective resin layer (surface protective layer) 16 is not particularly limited, and materials similar to those used as surface protective layers in conventional decorative paper can be used. Examples of materials that can be used for the protective resin layer (surface protective layer) 16 include acrylic urethane resins and ionizing radiation curable resins. Examples of acrylic urethane resins include reaction products containing an acrylic polyol compound as the main component and an isocyanate compound as the curing agent. Examples of ionizing radiation curable resins include compositions containing, as the main component, 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.

[0061] The protective resin layer (surface protective layer) 16 may be a single layer or a multi-layer structure consisting of two or three layers. When the protective resin layer 16 is a multi-layer structure, a glossy matte finish can be achieved by applying a matte resin and a glossy resin separately. It is also possible to create a textured finish by partially raising the resin. Furthermore, antibacterial agents, antiviral agents, etc. can also be added.

[0062] <Uses of Moisture-Proof Decorative Paper> As described above, the moisture-proof decorative paper 100 of this embodiment is suitable for applications in building materials such as interior doors, kitchen doors, storage doors, and sliding doors, but is also suitable for other applications, such as building materials for door frames, furniture doors, door facings, wall surfaces, and flooring, and is also suitable for use as facings for flush panels (flush doors). Flush panels comprise hollow flat members formed by bonding boards such as plywood or medium-density fiberboard (MDF) to the front and back of a core material made of frame materials such as square timber assembled lengthwise and crosswise. By using a small amount of inexpensive material for a large-area, thick flat member, they have the advantage of being lightweight and having sufficient strength, and are therefore widely used for applications such as interior doors and furniture doors.

[0063] In such flash panels, if the two sides of the panel are exposed to environments with significantly different temperatures and humidity, or if they are placed in an environment with drastic changes in temperature and humidity, the moisture content inside the front and back panels of the core material will become uneven, causing dimensional changes and resulting in warping of the entire flash panel.To prevent this, moisture-proof sheets (moisture-proof paper) are often attached to the front and back surfaces of the front and back panels of the core material.

[0064] The moisture-proof decorative paper 100 of this embodiment not only provides sufficient moisture resistance, but also maintains sufficient moisture resistance without any significant reduction in water vapor barrier properties. In such applications, it is suitable for use by being attached to the surfaces (the surfaces opposite the core material) of the front and back boards of a flash panel. The moisture-proof sheet (moisture-proof paper) attached to the back surfaces (the surfaces facing the core material) of the front and back boards of a flash panel may be a moisture-proof sheet (i.e., the moisture-proof decorative paper 100 of this embodiment) equipped with the moisture-proof layer 10 of this embodiment, but a conventional moisture-proof sheet (moisture-proof paper) other than the moisture-proof decorative paper 100 of this embodiment may also be used. Specifically, the moisture-proof sheet (moisture-proof paper) attached to the back surfaces (the surfaces facing the core material) of the front and back boards of a flash panel may be, for example, a moisture-proof sheet made of paper / polyethylene / paper, or a moisture-proof film made of a synthetic resin film with a metal vapor deposition and a protective layer.

[0065] <Effects> The moisture-proof decorative paper 100 of this embodiment has a lower moisture permeability (JIS Z 0208) than synthetic resin sheets such as vinyl chloride, polyethylene, and polypropylene, or moisture-proof sheets made of paper / polyethylene / paper. Therefore, a moisture-proof decorative paper with excellent moisture-proof performance can be provided. Furthermore, in the moisture-proof decorative paper 100, the mass of the paper substrate 11 is 50% by mass or more of the total mass of the moisture-proof decorative paper 100. Therefore, compared to conventional moisture-proof components such as synthetic resin sheets such as vinyl chloride, polyethylene, and polypropylene (90% by mass or more of plastic material) or moisture-proof sheets made of paper / polyethylene / paper (50% by mass or more of plastic material), the mass (content) of plastic used is smaller, thereby significantly reducing the amount of plastic material used in the moisture-proof decorative paper. Furthermore, decorative panels and doors and other building materials using this moisture-proof decorative paper 100 have high moisture-proof performance and, because they are composed of wood and paper components, are also highly recyclable.

[0066] The present disclosure will be described in more detail with reference to the following examples, but the present disclosure is not limited to these examples.

[0067] The following clay-coated papers 1 and 2 were prepared as paper substrates. Clay-coated paper 1: When the temperature was changed from 40°C and 20% relative humidity (RH) to 40°C and 90% relative humidity (RH), the dimensional change rate was CD = 0.75%, MD = 0.13%, and the basis weight was 60 g / m. ２ Clay coated paper 2: When the temperature was changed from 40°C and 20% relative humidity (RH) to 40°C and 90% relative humidity (RH), the dimensional change rate was CD = 0.55%, MD = 0.07%, and the basis weight was 60 g / m. ２

[0068] <Preparation of Moisture-Proof Paper> (Example 1) Clay-coated paper 1 was used as the paper substrate. ZAIKXEN AC (Sumitomo Seika Chemicals, an aqueous dispersion of an ammonium salt of an ethylene-acrylic acid copolymer) was applied to the surface of the paper substrate (on the clay coating layer) using a gravure coater to form a coating. The coating was dried to obtain a first laminate in which a first resin layer (thickness: 3 μm) was formed on the clay coating layer. Next, aluminum was vapor-deposited on the surface of the first resin layer while the first laminate was being transported using a roll-to-roll vacuum deposition device, forming an aluminum vapor-deposited layer (thickness: 66 nm). The method for measuring the thickness of the aluminum vapor-deposited layer will be described later. Next, Chemipearl S100 (Mitsui Chemicals, an aqueous dispersion of a metal salt of an ethylene-unsaturated carboxylic acid copolymer) was applied to the aluminum vapor-deposited layer using a gravure coater to form a coating, and the coating was dried to form a second resin layer (thickness: 3 μm), thereby obtaining the moisture-proof paper of Example 1.

[0069] (Examples 2 and 3) The moisture-proof papers of Examples 2 and 3 were obtained in the same manner as Example 1, except that the conveying speed of the first laminate was slowed down when vapor-depositing aluminum to form an aluminum vapor-deposited layer of the thickness shown in Table 1.

[0070] (Comparative Examples 1 and 2) The moisture-proof papers of Comparative Examples 1 and 2 were obtained in the same manner as Example 1, except that the conveying speed of the first laminate was increased when vapor-depositing aluminum to form an aluminum vapor-deposited layer of the thickness shown in Table 2.

[0071] Example 4 Clay-coated paper 2 was used as the paper substrate. An aqueous solution of Poval PVA 5-98 (a fully saponified PVA manufactured by Kuraray) was applied to the surface of the paper substrate (on the clay coating layer) using a gravure coater to form a coating. The coating was dried to obtain a first laminate in which a first resin layer (thickness: 4 μm) was formed on the clay coating layer. Next, aluminum was vapor-deposited on the surface of the first resin layer while the first laminate was being transported using a roll-to-roll vacuum deposition device, forming an aluminum vapor-deposited layer (thickness: 61 nm). Next, Chemipearl S500 (an emulsion of acid-modified polyolefin manufactured by Mitsui Chemicals) was applied to the aluminum vapor-deposited layer using a gravure coater to form a coating, and the coating was dried to form a second resin layer (thickness: 3 μm), thereby obtaining the moisture-proof paper of Example 4.

[0072] (Examples 5 and 6) The moisture-proof papers of Examples 5 and 6 were obtained in the same manner as Example 4, except that the conveying speed of the first laminate was slowed down when vapor-depositing aluminum to form an aluminum vapor-deposited layer of the thickness shown in Table 1.

[0073] (Comparative Examples 3 and 4) The moisture-proof papers of Comparative Examples 3 and 4 were obtained in the same manner as Example 4, except that the conveying speed of the first laminate was increased when vapor-depositing aluminum to form an aluminum vapor-deposited layer of the thickness shown in Table 2.

[0074] Example 7 Clay-coated paper 2 was used as the paper substrate. Takelac WPB-341 (Mitsui Chemicals, polyurethane resin emulsion) was applied to the surface of the paper substrate (clay coating layer) using a gravure coater to form a coating. The coating was dried to obtain a first laminate in which a first resin layer (thickness: 1 μm) was formed on the clay coating layer. Next, aluminum was vapor-deposited on the surface of the first resin layer while the first laminate was being transported using a roll-to-roll vacuum deposition device, forming an aluminum vapor-deposited layer (thickness: 68 nm). Zaixen AC (Sumitomo Seika Chemicals, aqueous dispersion of ammonium salt of ethylene-acrylic acid copolymer) was applied to the aluminum vapor-deposited layer using a gravure coater to form a coating, and the coating was dried to form a second resin layer (thickness: 4 μm), thereby obtaining the moisture-proof paper of Example 7.

[0075] (Examples 8 and 9) The moisture-proof papers of Examples 8 and 9 were obtained in the same manner as Example 7, except that the conveying speed of the first laminate was slowed down when vapor-depositing aluminum to form an aluminum vapor-deposited layer of the thickness shown in Table 1.

[0076] (Comparative Examples 5 and 6) The moisture-proof papers of Comparative Examples 5 and 6 were obtained in the same manner as in Example 7, except that the conveying speed of the first laminate was increased when vapor-depositing aluminum to form an aluminum vapor-deposited layer of the thickness shown in Table 2.

[0077] Next, a solid ink layer was formed by gravure printing using an ink containing soluble nitrocellulose and acrylic resin as a binder on the upper surface of the moisture-proof layer 10 (specifically, the second resin layer 14) laminated on the paper substrate 11 of each of Examples 1 to 9 and Comparative Examples 1 to 6. A pattern ink layer (printed pattern layer 15) was then formed thereon by gravure printing using an ink also containing soluble nitrocellulose and acrylic resin as a binder. Subsequently, a surface protective layer (protective resin layer) 16 was formed by gravure printing using a urethane-based acrylic polyol and isocyanate, thereby obtaining the moisture-proof decorative paper 100 of each of Examples 1 to 9 and Comparative Examples 1 to 6, each equipped with the moisture-proof layer 10 and the decorative layer 20.

[0078] <Evaluation> (Examples 1 to 9 and Comparative Examples 1 to 6) For the moisture-proof decorative paper of the Examples and Comparative Examples, the moisture-proof decorative paper was cut into a total of nine regions, three rows along the TD direction of the moisture-proof decorative paper and three rows along the MD direction of the moisture-proof decorative paper, to obtain nine measurement samples. The film thickness and water vapor permeability of the aluminum vapor deposition layer were measured using the measurement samples thus prepared.

[0079] [Film Thickness of Aluminum Vapor-Deposited Layer] The measurement sample was embedded in UV-curable resin. The measurement sample was cut using a cryomicrotome to expose a cross section, and a specimen for cross-sectional observation was obtained. The obtained specimen was observed using a scanning electron microscope (observation magnification: 50,000 times) and an image of the cross section was taken. The thickness of the aluminum vapor-deposited layer was measured from the obtained image. The average value of the thickness of the aluminum vapor-deposited layer measured for each of the nine measurement samples was taken as the film thickness of the aluminum vapor-deposited layer. The results are shown in Tables 1 and 2.

[0080] [Water vapor permeability] According to JIS K7129-2, the water vapor permeability was measured by the Mocon method under conditions of a temperature of 40°C and a relative humidity (RH) of 90%. Measurements were performed twice for each of the nine measurement samples, yielding a total of 18 measurement data. The average value of the 18 data was adopted as the water vapor permeability. The standard deviation of the 18 data was also calculated. The results thus calculated (unit of water vapor permeability: g / (m ２ The results are shown in Tables 1 and 2.

[0081]

[0082]

[0083] As is clear from the results in Tables 1 and 2, in Comparative Examples 1 to 6, in which the aluminum vapor-deposited layer was less than 60 nm thick, the average water vapor permeability and standard deviation were large and the water vapor barrier property was unstable, whereas the moisture-proof papers of Examples 1 to 9, which had an aluminum vapor-deposited layer with a thickness of 60 nm or more, consistently achieved excellent water vapor barrier property. In other words, the moisture-proof papers of Examples 1 to 9, which had an aluminum vapor-deposited layer with a thickness of 60 nm or more, achieved excellent water vapor barrier property evenly (with good yield).

[0084] The moisture-proof decorative paper in each example is provided with a moisture-proof layer comprising an aluminum vapor deposition layer of 60 nm or more, which has been confirmed to have improved water vapor barrier performance, and is expected to have the effect of reducing warping of the decorative board caused by moisture absorption and release due to changes in indoor temperature and humidity compared to conventional products, and to reduce the amount of plastic material used. This has verified the objective of the present invention: to prevent warping of the decorative board even when used in places with large differences in temperature and humidity environments on both sides, and to provide a moisture-proof decorative paper that is also environmentally friendly.

[0085] Furthermore, for example, the present invention can take the following configurations. (1) Moisture-proof decorative paper comprising a moisture-proof layer and a decorative layer in this order on at least one surface of a paper substrate, the moisture-proof layer having a structure in which a first resin layer, an aluminum vapor-deposited layer, and a second resin layer are laminated in this order from the paper substrate side, the aluminum vapor-deposited layer having a thickness of 60 nm or more, and the decorative layer comprising a printed layer and a protective resin layer in this order from the moisture-proof layer side. (2) Moisture-proof decorative paper according to (1) above, in which the second resin layer contains a polyolefin having an acidic group. (3) Moisture-proof decorative paper according to (1) or (2) above, in which the first resin layer contains at least one selected from the group consisting of a polyolefin having an acidic group, a polyvinyl alcohol-based resin, and a polyurethane-based resin. (4) Moisture-proof decorative paper having a water vapor transmission rate of 5 g / (m) at a temperature of 40°C and a relative humidity of 90%. ２ (1) The moisture-proof decorative paper according to any one of (1) to (3) above, wherein the second resin layer contains an ethylene-unsaturated carboxylic acid copolymer. (2) The moisture-proof decorative paper according to any one of (1) to (4) above, wherein the second resin layer contains an ethylene-unsaturated carboxylic acid copolymer. (3) The moisture-proof decorative paper according to any one of (1) to (5) above, wherein the mass of paper components contained in the paper base material is 50 mass% or more based on the mass of the entire moisture-proof decorative paper. (4) The moisture-proof decorative paper according to any one of (1) to (3) above, wherein the moisture-proof decorative paper has a metallic design as a design expression of a pattern on the moisture-proof decorative paper.

[0086] DESCRIPTION OF SYMBOLS 11: Paper base material 12: First resin layer 13: Aluminum vapor deposition layer 14: Second resin layer 15: Printed pattern layer (printed layer) 16: Protective resin layer (surface protective layer) 100: Moisture-proof decorative paper 10: Moisture-proof layer 20: Decorative layer

Claims

1. A moisture-proof decorative paper comprising a moisture-proof layer and a decorative layer in this order on one side of a paper base material, the moisture-proof layer being a laminate having a structure in which a first resin layer, an aluminum vapor deposition layer, and a second resin layer are laminated in this order from the paper base material side, the aluminum vapor deposition layer having a thickness of 60 nm or more, and the decorative layer comprising a printing layer and a protective resin layer in this order from the moisture-proof layer side.

2. The moisture-proof decorative paper according to claim 1, wherein the second resin layer contains a polyolefin having an acidic group.

3. A moisture-proof decorative paper according to claim 1 or claim 2, wherein the first resin layer contains at least one selected from the group consisting of polyolefins having acidic groups, polyvinyl alcohol-based resins, and polyurethane-based resins.

4. The water vapor permeability at a temperature of 40°C and a relative humidity of 90% is 5 g / (m ２ 3. The moisture-proof decorative paper according to claim 1, wherein the moisture-proof decorative paper has a moisture-proof life of 24 hours or less.

5. The moisture-proof decorative paper according to claim 1 or 2, wherein the second resin layer contains an ethylene-unsaturated carboxylic acid copolymer.

6. A moisture-proof decorative paper according to claim 1 or claim 2, wherein the mass of the paper components contained in the paper base material is 50% by mass or more based on the mass of the entire moisture-proof decorative paper.

7. The moisture-proof decorative paper according to claim 1 or 2, wherein the design expression of the pattern on the moisture-proof decorative paper has a metallic design.

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