JP5900091B2 - Decorative sheet and decorative plate having the same - Google Patents

Description

  The present invention relates to a decorative sheet excellent in use suitability (adhesiveness), specularity and processing suitability, and a decorative board using the decorative sheet.

As a decorative board used for furniture, kitchen product cabinets, floor tiles, wall panels, kitchen sinks, etc., a decorative sheet printed with a wood grain pattern on a building material board is generally bonded with an adhesive. It is used. And the decorative sheet used for such a decorative plate has processability such as flexibility, machinability, break resistance, stain resistance, scratch resistance, water resistance, chemical resistance, weather resistance, etc. Various characteristics such as suitability for use are required.
In order to satisfy these requirements, a technique for applying a surface protective layer to the surface of a substrate that sufficiently satisfies processability is used, and an ionizing radiation curable resin composition is preferably used for the surface protective layer. . The ionizing radiation curable resin composition is a composition that is cured by ionizing radiation such as ultraviolet rays and electron beams, and the surface protective layer using the ionizing radiation curable resin composition has a high crosslinking density, so that surface strength such as abrasion resistance can be easily obtained. Various advantages are obtained.
However, the surface state of the surface protective layer is easily affected by the unevenness of the lower layer, and in particular, it is very difficult to impart specularity (surface smoothness) that has been gaining popularity among consumers seeking high-quality feeling in recent years. Furthermore, it has been very difficult to ensure suitability for use (adhesion) with an ionizing radiation resin having a high crosslinking density.
Regarding the provision of this specularity (surface smoothness), Patent Document 1 proposes that the viscosity at the time of application of the reactive hot melt adhesive is 10000 to 20000 mPa · s. This did not consider the suitability for use (adhesion).

Japanese Patent Laid-Open No. 2003-21116

  Under such circumstances, the present invention uses a decorative sheet having good useability (adhesion) between the surface protective layer and the adhesive layer, excellent specularity and good processability, and the decorative sheet. It is an object to provide a decorative board.

As a result of intensive studies in order to solve the above problems, the present inventors have determined that the base material, the thickness of the surface protective layer and the adhesive layer, and the characteristics of the adhesive constituting the adhesive layer have a specific range. Thus, the present inventors have found that the problems of the present invention can be solved, and have completed the present invention.
The gist of the present invention is as follows.

[1] On a base material, at least one layer selected from a colored hiding layer and a colored layer, an adhesive layer, a surface protective layer, and a transfer film are provided in this order, and the thickness of the base material is 40 μm or more. The thickness of the surface protective layer is 2 to 20 μm, the thickness of the adhesive layer is 1 to 18 μm, and the glass transition temperature Tg of the adhesive constituting the adhesive layer (according to JIS K7121-1987) ) Is −30 to 20 ° C., and the initial hardness (according to JIS K 6253: 2006) of the adhesive is 5 to 95.
[2] A decorative board having the decorative sheet according to [1].

  ADVANTAGE OF THE INVENTION According to this invention, the decorative sheet which has the favorable use aptitude (adhesiveness) of a surface protective layer and an adhesive bond layer, the outstanding specularity, and the favorable processability, and a decorative board using this decorative sheet are provided. Can do.

It is a schematic diagram which shows the cross section of the decorative sheet of this invention. It is a schematic diagram which shows the cross section of the decorative board using the decorative sheet of this invention.

[Decorative sheet]
The decorative sheet of the present invention has at least one layer selected from a colored hiding layer and a colored layer, an adhesive layer, a surface protective layer, and a transfer film in this order on the substrate, and the thickness of the substrate is 40 μm or more, the thickness of the surface protective layer is 2 to 20 μm, the thickness of the adhesive layer is 1 to 18 μm, and the glass transition temperature Tg (JIS K7121) of the adhesive constituting the adhesive layer -1987.) is -30 to 20 ° C., and the initial hardness (according to JIS K 6253: 2006) of the adhesive is 5 to 95. With this configuration, the decorative sheet of the present invention has good useability (adhesion) between the surface protective layer and the adhesive layer, excellent specularity, and good processability.

Hereinafter, the specific layer structure and the material of each layer of the decorative sheet of the present invention will be described with reference to FIG. One example of the decorative sheet 1 shown in FIG. 1 includes a colored concealing layer 3, a colored layer 4, an adhesive layer 5, a surface protective layer 6 that is a cured product of an ionizing radiation curable resin composition, and a transfer on a substrate 2. Films 7 are laminated in this order, and a back surface primer layer 8 is provided on the back surface of the substrate 2. In the present invention, other layers may exist between the layers.
When providing both the colored hiding layer 3 and the colored layer 4, the decorative sheet 1 of the present invention preferably has a base, a colored hiding layer, a colored layer, and an adhesive layer in this order as shown in FIG.

"Base material"
As the substrate 2, a substrate having a thickness of 40 μm or more is used. When the thickness of the base material 2 is less than 40 μm, the strength as a decorative sheet is lowered and the specularity as a decorative plate is lowered. From this viewpoint and the viewpoint of cost reduction, the thickness of the substrate 2 is preferably 40 to 650 μm, more preferably 40 to 500 μm, more preferably 45 to 500 μm, and still more preferably 48 to 250 μm.
In addition, in this invention, the back surface of the base material 2 means the surface on the opposite side to the coloring concealment layer 3 among the surfaces of the base material 2.
As specific examples of the substrate 2, various plastic films, plastic sheets, metal foils, metal sheets, metal plates, and the like can be appropriately selected depending on applications. Each of these materials may be used alone, but may be a laminate in which the above materials are arbitrarily combined.

As the plastic film or plastic sheet, plastic films and plastic sheets made of various resins such as olefin resin, acrylic resin, polyester resin, vinyl chloride resin and polyamide resin are preferable. More specifically, as the resin, polyethylene resin, polypropylene resin, polymethylpentene resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl alcohol resin, vinyl chloride-vinyl acetate copolymer resin, ethylene-vinyl acetate copolymer resin , Ethylene-vinyl alcohol copolymer resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polyethylene naphthalate-isophthalate copolymer resin, polymethyl methacrylate resin, polyethyl methacrylate resin, polybutyl acrylate resin, nylon 6 or nylon And polyamide resin represented by No. 66, cellulose triacetate resin, cellophane, polystyrene resin, polycarbonate resin, polyarylate resin, or polyimide resin.
Among these materials, olefin-based resins such as polyethylene resin and polypropylene resin are preferable from the viewpoint of production cost and influence on the environment during production.

When such a plastic film or plastic sheet is used as the base material 2, in order to improve the adhesion to the layer provided thereon, physical or other methods such as an oxidation method or a concavo-convex method are provided on one or both sides as desired. It is preferable to apply a chemical or chemical surface treatment.
Examples of the oxidation method include corona discharge treatment, chromium oxidation treatment, flame treatment, hot air treatment, and ozone-ultraviolet treatment method. Examples of the unevenness method include a sand blast method and a solvent treatment method. These surface treatments are appropriately selected according to the type of the substrate 2, but in general, the corona discharge treatment method is preferable from the viewpoints of effects and operability.
In addition, the base material 2 may be subjected to a treatment such as forming a primer layer for enhancing the usability (adhesion) between the base material 2 and each layer, and may be applied for painting or design. A pattern from various viewpoints may be formed in advance.

  As metal foil, a metal sheet, or a metal plate, what consists of aluminum, iron, stainless steel, or copper, for example can be used, and what gave these metals by plating etc. can also be used. In addition to these, composites of various materials such as fiber reinforced plastic (FRP) plates, paper honeycombs with iron plates pasted on both sides, and two aluminum plates sandwiched with polyethylene resin are also used as the base material 2 it can.

<Coloring hiding layer>
In the present invention, at least one layer selected from the colored hiding layer 3 and the colored layer 4 is provided on the substrate 2. That is, both the colored concealment layer 3 and the colored layer 4 may be included, only the colored concealment layer 3 may be included, or only the colored layer 4 may be included.
The colored concealment layer 3 in the present invention is provided as necessary for the purpose of improving the design of the decorative sheet 1 and for the purpose of improving the adhesion between the base material 2 and the colored layer 4 when the colored sheet 4 is further provided. Is preferred. The colored concealment layer 3 can adjust the surface color by giving the intended color when the substrate 2 is colored or when there is color unevenness. The colored concealment layer 3 is usually formed with an opaque color for the purpose of concealing the base material 2 and the base, but it can also be formed with a colored transparent color to make use of the pattern of the base 2 and the base. .

As the ink used for forming the colored hiding layer 3, an ink obtained by appropriately mixing a binder, a colorant such as a pigment or a dye, an extender pigment, a solvent, a stabilizer, a plasticizer, a catalyst, or a curing agent is used. The binder is not limited, for example, polyurethane resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-acrylic copolymer resin, chlorinated polypropylene resin, acrylic resin, polyester-based resin. Examples include resins, polyamide resins, butyral resins, polystyrene resins, nitrocellulose resins, and cellulose acetate resins. These may be used alone or in combination of two or more.
The colorant may be appropriately selected from the use of the decorative sheet 1 and the color compatibility with the colored layer 4. For example, carbon black (black), iron black, titanium white, antimony white, yellow lead, titanium yellow, Petals, inorganic pigments such as cadmium red, ultramarine blue, cobalt blue, organic pigments or dyes such as quinacridone red, isoindolinone yellow, phthalocyanine blue, metal pigments made of scaly foils such as aluminum and brass, titanium dioxide coated mica And pearlescent (pearl) pigments composed of scaly foil pieces such as basic lead carbonate.
The thickness of the colored hiding layer 3 is preferably 0.5 to 20 μm, more preferably 1 to 10 μm, and still more preferably 1 to 6 μm.

<Colored layer>
The colored layer 4 shown in FIG. 1 gives decorativeness to the decorative sheet 1 and is also called a decorative layer. The colored layer 4 includes both the pattern layer and the entire solid layer, but the pattern layer is preferable from the viewpoint of design.
The colored layer 4 is formed by printing various colors and / or patterns using ink and a printing machine. The pattern can be formed by multicolor printing with normal yellow, red, blue, and black process colors, or by multicolor printing with special colors prepared by preparing individual color plates constituting the pattern. Is done. In addition, the whole surface solid layer as the colored layer 4 in this invention is a layer which printed the ink with respect to the whole surface of an object, without forming a pattern. As the pattern ink used for the colored layer 4, the same ink as that used for the colored hiding layer 3 can be used.
In the present invention, the colored hiding layer 3 may be provided with a decorative property so that the colored hiding layer 3 is not provided but the colored hiding layer 3 may be provided. By doing so, you may have only the colored layer 4 without having the colored hiding layer 3.

<Adhesive layer>
In the present invention, the adhesive layer 5 is provided between at least one layer selected from the colored hiding layer and the colored layer and the surface protective layer 6. A layer other than the adhesive layer 5 may exist between the colored hiding layer 3 or the colored layer 4 and the surface protective layer 6.
In the present invention, the adhesive layer 5 needs to have a thickness of 1 to 18 μm. When the thickness of the adhesive layer 5 exceeds 18 μm, cohesive failure easily occurs in the layer of the adhesive layer 5, and as a result, the suitability (adhesiveness) between the surface protective layer 6 and the adhesive layer 5 decreases. It will be. Further, if the thickness of the adhesive layer 5 is less than 1 μm, sufficient adhesive strength cannot be obtained, and the suitability (adhesiveness) between the surface protective layer 6 and the adhesive layer 5 decreases. From the above viewpoint, the thickness of the adhesive layer 5 is preferably 1 to 15 μm, and more preferably 3 to 10 μm.

  Moreover, the glass transition temperature Tg (based on JISK7121-1987) of the adhesive which comprises the adhesive bond layer 5 which concerns on this invention needs to be -30 degreeC-20 degreeC. When the glass transition temperature Tg is lower than −30 ° C., the adhesive itself is flexible and the adhesiveness is remarkably lowered under the actual use temperature condition, causing cohesive failure in the adhesive layer. Further, when the glass transition temperature Tg exceeds 20 ° C., a heat laminate of less than 150 ° C. is insufficiently melted and the adhesiveness is remarkably lowered. Therefore, a high temperature (150 ° C. or higher) is required during the heat lamination. Deterioration and production suitability decrease occur. From these viewpoints, the glass transition temperature Tg of the adhesive is preferably −20 ° C. to 10 ° C.

  Furthermore, the initial hardness (conforming to JIS K 6253: 2006) of the adhesive constituting the adhesive layer 5 according to the present invention is required to be 5 to 95. When the initial hardness is less than 5, the back surface unevenness of the base material 2 is formed at the time of winding after lamination by heat sealing (hereinafter, also referred to as “thermal fusion”), and mirror surface properties are ensured. become unable. On the other hand, if the initial hardness is 5 or more, even when winding up after lamination by heat sealing, the back surface unevenness of the substrate 2 is not affected, and the surface smoothness of the transfer film is obtained as it is and the mirror surface is obtained. Can do. From this viewpoint, the initial hardness of the adhesive is preferably 10 to 95.

  The adhesive used for the adhesive layer 5 is not particularly limited as long as it is an adhesive that satisfies the glass transition temperature Tg and the initial hardness, but is preferably a heat-sensitive adhesive suitable for heat seal specifications. A heat-sensitive adhesive is generally a solid at normal temperature, melts or softens by heating, expresses adhesiveness, solidifies and solidifies when cooled, and has a thermoplastic resin or thermosetting resin as a main component. Refers to the adhesive. This is dissolved in an appropriate solvent or melted by heating, applied to one or both adhesive surfaces of the adherend, heated and superposed, and then cooled to adhere. is there.

  Thermoplastic resin adhesives used as heat-sensitive adhesives include, for example, (meth) acrylic resin adhesives, polyurethane resin adhesives, polyester adhesives, polyamide resin adhesives, (meth) acrylic ester-olefin copolymers. Polymer resin adhesive, vinyl chloride acetate resin adhesive, ethylene-vinyl acetate copolymer resin adhesive, ionomer resin adhesive, olefin-α olefin copolymer resin adhesive, and other adhesive-adhesive resin adhesives, and Preferred examples include thermoplastic resin adhesives that are the main components of olefin resins and foamed resin compositions, and blends with thermoplastic resins that are the main components of the film layer. Among these, (meth) acrylic resin adhesives, polyester adhesives, and polyurethane resin adhesives are more preferable.

  The thermosetting tree species adhesive used as the heat-sensitive adhesive preferably includes a composition having a property of causing a chemical reaction by heat to cause crosslinking, for example, a two-component curable urethane adhesive, a polyester urethane adhesive, Polyether urethane adhesives, acrylic adhesives, polyester adhesives, polyamide adhesives, polyvinyl acetate adhesives, epoxy adhesives, rubber adhesives, etc. A two-component curable urethane-based adhesive is suitable. By using a two-component curable urethane adhesive, a stronger adhesive strength can be obtained, and the decorative sheet 1 having excellent flexibility can be provided.

  In any adhesive, various known methods such as roll coating, gravure coating, air knife coating, comma coating and the like are used as the coating method, and gravure coating and comma coating are preferable from the viewpoint of productivity. Used.

<Surface protective layer>
In the present invention, the surface protective layer 6 may be a cured product of a thermosetting resin composition, but is preferably a cured product of an ionizing radiation curable resin composition. Of the ionizing radiation curable resin compositions, electron beam curable resin compositions are preferred. The electron beam curable resin composition can reduce the amount of solvent used, is more preferable from the viewpoint of environment and health, and does not require a photopolymerization initiator, and can provide stable curing characteristics. It is.
The ionizing radiation curable resin composition has an energy quantum capable of crosslinking and polymerizing molecules in electromagnetic waves or charged particle beams, that is, crosslinked and cured by irradiation with ultraviolet rays or electron beams. It refers to a resin composition.
The surface protective layer 6 imparts suitability for use to the decorative sheet 1 such as stain resistance, scratch resistance, water resistance, chemical resistance, weather resistance, and the like depending on the application.

(Ionizing radiation curable resin composition)
As the ionizing radiation curable resin composition used for the surface protective layer 6, a conventionally known compound can be appropriately used. Specifically, it can be appropriately selected from polymerizable monomers, polymerizable oligomers, or prepolymers conventionally used as ionizing radiation curable resins.
Typically, a (meth) acrylate monomer having a radical polymerizable unsaturated group in the molecule is suitable as the polymerizable monomer, and among them, a polyfunctional (meth) acrylate is preferable. Here, “(meth) acrylate” means “acrylate or methacrylate”, and other similar ones have the same meaning. The polyfunctional (meth) acrylate is not particularly limited as long as it is a (meth) acrylate having two or more ethylenically unsaturated bonds in the molecule. These polyfunctional (meth) acrylates may be used singly or in combination of two or more.

  Next, as the polymerizable oligomer, an oligomer having a radical polymerizable unsaturated group in the molecule, for example, epoxy (meth) acrylate, urethane (meth) acrylate, polyester (meth) acrylate, polyether (meth) acrylate The system etc. are mentioned. Here, the epoxy (meth) acrylate oligomer can be obtained, for example, by reacting (meth) acrylic acid with an oxirane ring of a relatively low molecular weight bisphenol type epoxy resin or novolak type epoxy resin and esterifying it. . Further, a carboxyl-modified epoxy (meth) acrylate oligomer obtained by partially modifying this epoxy (meth) acrylate oligomer with a dibasic carboxylic acid anhydride can also be used. The urethane (meth) acrylate oligomer can be obtained, for example, by esterifying a polyurethane oligomer obtained by reaction of polyether polyol or polyester polyol and polyisocyanate with (meth) acrylic acid. Examples of polyester (meth) acrylate oligomers include esterification of hydroxyl groups of polyester oligomers having hydroxyl groups at both ends obtained by condensation of polycarboxylic acid and polyhydric alcohol with (meth) acrylic acid, It can be obtained by esterifying the terminal hydroxyl group of an oligomer obtained by adding an alkylene oxide to a carboxylic acid with (meth) acrylic acid. The polyether (meth) acrylate oligomer can be obtained by esterifying the hydroxyl group of the polyether polyol with (meth) acrylic acid. Among the above polymerizable oligomers, those containing a polyfunctional urethane acrylate oligomer are preferred as the ionizing radiation curable resin, and those containing a bifunctional urethane acrylate oligomer are particularly preferred.

  Furthermore, other polymerizable oligomers include polybutadiene (meth) acrylate oligomers with high hydrophobicity having (meth) acrylate groups in the side chain of polybutadiene oligomers, and silicone (meth) acrylate oligomers having polysiloxane bonds in the main chain. In a molecule such as an aminoplast resin (meth) acrylate oligomer modified with an aminoplast resin having many reactive groups in a small molecule, or a novolak epoxy resin, bisphenol epoxy resin, aliphatic vinyl ether, aromatic vinyl ether, etc. There are oligomers having a cationic polymerizable functional group.

  In the present invention, a monofunctional (meth) acrylate can be appropriately used in combination with the polyfunctional (meth) acrylate and the like within a range that does not impair the object of the present invention, for the purpose of reducing the viscosity. . These monofunctional (meth) acrylates may be used alone or in combination of two or more.

  Moreover, it is preferable that the number average molecular weights (polystyrene conversion number average molecular weight measured by GPC method) of ionizing radiation-curable resin are 1000-10000, and 2000-10000 are more preferable. If the number average molecular weight is within the above range, the surface protective layer 6 can be easily formed because the processability is excellent and the coating agent composition has a suitable thixotropy.

  When an ultraviolet curable resin composition is used as the ionizing radiation curable resin composition, the photopolymerization initiator may be added in an amount of about 0.1 to 10 parts by mass with respect to 100 parts by mass of the ultraviolet curable resin. desirable. The initiator for photopolymerization can be appropriately selected from those conventionally used and is not particularly limited. Moreover, the photosensitizer conventionally used conventionally can be used as needed.

Moreover, various additives can be mix | blended with the ionizing radiation-curable resin composition in this invention according to the desired physical property of the obtained cured resin layer. Examples of this additive include a weather resistance improver, an abrasion resistance improver, a polymerization inhibitor, a crosslinking agent, an infrared absorber, an antistatic agent, an adhesion improver, a leveling agent, a thixotropic agent, a coupling agent, A plasticizer, an antifoamer, a filler, a solvent, a coloring agent, etc. are mentioned.
Here, as the weather resistance improving agent, an ultraviolet absorber or a light stabilizer can be used. The ultraviolet absorber may be either inorganic or organic. As the inorganic ultraviolet absorber, titanium dioxide, cerium oxide, zinc oxide or the like having an average particle size of about 5 to 120 nm can be preferably used. Examples of the organic ultraviolet absorber include benzotriazole-based compounds, specifically 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-3,5-di-tert-). Amylphenyl) benzotriazole, 3- [3- (benzotriazol-2-yl) -5-tert-butyl-4-hydroxyphenyl] propionic acid ester of polyethylene glycol, and the like. On the other hand, examples of the light stabilizer include hindered amines, specifically 2- (3,5-di-tert-butyl-4-hydroxybenzyl) -2′-n-butylmalonate bis (1,2,2). , 6,6-pentamethyl-4-piperidyl), bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, tetrakis (2,2,6,6-tetramethyl-4-piperidyl)- 1,2,3,4-butanetetracarboxylate and the like. In addition, as the ultraviolet absorber or light stabilizer, a reactive ultraviolet absorber or light stabilizer having a polymerizable group such as a (meth) acryloyl group in the molecule can be used.

Examples of the wear resistance improver include, for inorganic substances, spherical particles such as α-alumina, silica, kaolinite, iron oxide, diamond, and silicon carbide. Examples of the particle shape include a sphere, an ellipsoid, a polyhedron, a scale shape, and the like. Although there is no particular limitation, a spherical shape is preferable. Organic materials include synthetic resin beads such as cross-linked acrylic resin and polycarbonate resin. The particle size is usually about 30 to 200% of the film thickness. Among these, spherical α-alumina is particularly preferable because it has high hardness and a large effect on improving wear resistance, and it is relatively easy to obtain spherical particles.
Examples of the polymerization inhibitor include hydroquinone, p-benzoquinone, hydroquinone monomethyl ether, pyrogallol, and t-butylcatechol. Examples of the crosslinking agent include a polyisocyanate compound, an epoxy compound, a metal chelate compound, an aziridine compound, and an oxazoline compound. Used.
As the filler, for example, barium sulfate, talc, clay, calcium carbonate, aluminum hydroxide and the like are used.
Examples of the colorant include known coloring pigments such as quinacridone red, isoindolinone yellow, phthalocyanine blue, phthalocyanine green, titanium oxide, and carbon black.
As the infrared absorber, for example, a dithiol metal complex, a phthalocyanine compound, a diimmonium compound, or the like is used.

The ionizing radiation curable resin composition may contain silicone (meth) acrylate for the purpose of improving specularity and glossiness.
The silicone (meth) acrylate is preferably a mono- or bifunctional silicone methacrylate having one or two methacryl groups from the viewpoint of improving specularity and gloss, and has a molecular weight of 1,000 to 6,000, more preferably 3. 3,000 to 6,000, functional group equivalent (molecular weight / number of functional groups) 500 to 3,000, more preferably 1,500 to 3,000.
The silicone acrylate is preferably a polyfunctional silicone acrylate having a plurality of acrylic groups, preferably 4 or more, and more preferably 4-6, and a molecular weight of 3,000-100,000, more preferably 10,000- Examples include those having conditions of 30,000, functional group equivalent (molecular weight / functional group number) 750 to 25,000, more preferably 3,000 to 6,000.
The content of the monofunctional or bifunctional silicone methacrylate is 1.5 to 20 parts by mass, more preferably 2 to 4 parts by mass with respect to 100 parts by mass of the ionizing radiation curable resin, from the viewpoint of improving specularity and glossiness. It is. Moreover, content of the said polyfunctional silicone acrylate is 1-20 mass parts with respect to 100 mass parts of ionizing radiation curable resin, More preferably, it is 1-10 mass parts.
The ratio of the content of silicone methacrylate and silicone acrylate is from 1: 1 to 1: 5, more preferably from 1: 2 to 1: 3 (both mass ratios).

(Formation of surface protective layer)
In the present invention, the above-mentioned ionizing radiation curable component polymerizable monomer, polymerizable oligomer and various additives are homogeneously mixed at a predetermined ratio to prepare a coating solution comprising an ionizing radiation curable resin composition. . The viscosity of the coating solution is not particularly limited as long as it is a viscosity capable of forming an uncured resin layer on the coated surface by a coating method described later.
In the present invention, the coating solution thus prepared is applied by a known method such as gravure coating, bar coating, roll coating, reverse roll coating, comma coating, preferably gravure coating, and an uncured resin layer is formed. Let it form.
In the present invention, the thickness of the surface protective layer 6 after curing is required to be 2 to 20 μm, and preferably 3 to 15 μm, from the viewpoints of specularity and processability. When the thickness is less than 2 μm, the mirror surface property of the decorative sheet and the decorative plate is lowered, and when it exceeds 20 μm, the processability is lowered.

In the present invention, the uncured resin layer formed as described above is irradiated with ionizing radiation such as an electron beam and ultraviolet rays to cure the uncured resin layer. Here, when an electron beam is used as the ionizing radiation, the acceleration voltage can be appropriately selected according to the resin used and the thickness of the layer, but the uncured resin layer is usually cured at an acceleration voltage of about 70 to 300 kV. preferable.
In addition, in the electron beam irradiation, the transmission capability increases as the acceleration voltage increases. Therefore, when the base material 2 that deteriorates due to the electron beam is used as the base material 2, the penetration depth of the electron beam and the thickness of the resin layer are used. By selecting the accelerating voltage so that the two are substantially equal, it is possible to suppress the irradiation of the extra electron beam to the base material 2 and to minimize the deterioration of the base material 2 due to the excess electron beam. Can do.
The irradiation dose is preferably such that the crosslinking density of the resin layer is saturated, and is usually selected in the range of 5 to 300 kGy (0.5 to 30 Mrad), preferably 10 to 70 kGy (1 to 7 Mrad).
Furthermore, there is no restriction | limiting in particular as an electron beam source, For example, various electron beam accelerators, such as a cock loft Walton type, a bande graft type, a resonance transformer type, an insulated core transformer type, or a linear type, a dynamitron type, a high frequency type, etc. Can be used.
When ultraviolet rays are used as the ionizing radiation, those containing ultraviolet rays having a wavelength of 190 to 380 nm are emitted. There is no restriction | limiting in particular as an ultraviolet-ray source, For example, a high pressure mercury lamp, a low pressure mercury lamp, a metal halide lamp, a carbon arc lamp, etc. are used.
The cured resin layer thus formed has various functions by adding various additives, for example, a so-called hard coat function, anti-fogging coat function, and anti-fouling coat having high hardness and scratch resistance. A function, an antiglare coating function, an antireflection coating function, an ultraviolet shielding coating function, an infrared shielding coating function, and the like can be provided.

<Transfer film>
As the transfer film 7, a conventionally known film can be used, and the thickness is preferably 15 to 200 μm. If thickness is 15 micrometers or more, it will become easy to peel when peeling the film 7 for transcription | transfer. If thickness is 200 micrometers or less, the mirror surface property of the decorative sheet 1 can be ensured more suitably. From the above viewpoint, the thickness of the transfer film 7 is more preferably 18 to 195 μm, and still more preferably 22 to 190 μm.
Specifically, polyethylene terephthalate (PET) film, polybutylene terephthalate (PBT) film, polyethylene naphthalate (PEN) film, polyethylene (PE) film, polypropylene (PP) film, acrylonitrile-butadiene-styrene Examples thereof include a copolymer resin (ABS resin) film and a polycarbonate (PC) film. In these, a polyester-type film is preferable from a viewpoint of mirror surface maintenance (surface smoothness), and a stretched polyester film is especially preferable. In the present invention, since the transfer film 7 plays a role as a protective film (masking film), cost reduction and environmental consideration can be achieved by material reduction and process simplification. Further, by providing the transfer film 7 having smoothness coated with the surface protective layer 6, the decorative sheet 1 having excellent specularity that is not affected by the surface properties (surface irregularities) of the substrate 2 can be produced. .
Further, the wetting index of the transfer film 7 is preferably 35 to 50 mN / m, more preferably 40 to 45 mN / m from the viewpoint of achieving both adhesion and peelability. In the present specification, the wetting index is a value measured in accordance with JIS K 6768.
The process of peeling off the transfer film 7 and transferring the film (i) after bonding the substrate 2 and the transfer film 7, that is, laminating the transfer film 7 with other layers, the decorative sheet 1. (Ii) In order to give a role as a protective film (masking film), it may be performed after the decorative sheet 1 is bonded to the substrate 11 described later, and (iii) after construction It may be performed immediately before use, and is not particularly limited.

《Primer layer》
In the present invention, a primer layer may be provided between arbitrary layers for the purpose of improving the adhesion between the respective layers and imparting sufficient weather resistance to the decorative sheet 1.
As the ink used for forming the primer layer, an ink in which an extender, a solvent, a stabilizer, a plasticizer, a catalyst, a curing agent and the like are appropriately mixed with the binder is used as necessary. The binder is not limited, and examples thereof include ester resins, urethane resins, acrylic resins, urethane-acrylic copolymer resins, polycarbonate resins, vinyl chloride-vinyl acetate copolymers, polyvinyl butyral resins, and nitrocellulose resins. These resins may be used alone or in combination of two or more. There is no limitation on the method for applying the primer layer. For example, one or two or more resins are used as a coating composition or ink composition using a solvent or the like, and an appropriate application means such as a roll coating method or a gravure printing method is used. Can be formed.

It is preferable to add a weather resistance improver to the resin composition constituting the primer layer from the viewpoint of improving the weather resistance of the decorative sheet 1. Examples of the weather resistance improver include an ultraviolet absorber (hereinafter sometimes referred to as “UVA”) and a light stabilizer. The ultraviolet absorber (UVA) absorbs harmful ultraviolet rays and improves the long-term weather resistance and stability of the decorative sheet 1 of the present invention. In addition, the light stabilizer itself absorbs little ultraviolet light, but stabilizes by efficiently capturing harmful free radicals generated by ultraviolet energy.
Examples of these ultraviolet absorbers and light stabilizers include those used in the ionizing radiation curable resin composition described above.

  The thickness of the primer layer is preferably 0.5 to 20 μm. When the thickness of the primer layer is within the above range, sufficient adhesion and weather resistance can be obtained, and further, cracking hardly occurs during processing. From the above points, the thickness of the primer layer is more preferably 1 to 20 μm, more preferably 1 to 10 μm, and still more preferably 1 to 6 μm.

≪Back primer layer≫
The base material 2 may be provided with a primer layer 8 on the back surface for the purpose of improving adhesiveness with various adherends. It does not specifically limit as a material used for formation of the back surface primer layer 8, An acrylic resin, a vinyl chloride-vinyl acetate copolymer, polyester, a polyurethane, chlorinated polypropylene, chlorinated polyethylene etc. are mentioned. The material used for the back primer layer 8 is appropriately selected depending on the adherend.

The decorative sheet 1 of the present invention has the above-mentioned respective layers, but may have other layers within a range that does not impair the object of the present invention.
Moreover, as the decorative sheet 1 of this invention, it is preferable that total thickness is 120-650 micrometers, it is more preferable that it is 180-500 micrometers, and it is still more preferable that it is 180-250 micrometers.

[Decorative board]
The decorative sheet 1 of the present invention can be used as a decorative board by sticking to various substrates. Specifically, as shown in FIG. 2, the decorative sheet 1 is adhered to the substrate 11 via the substrate adhesive layer 10. Examples of the decorative board 11 include wood veneer, wood plywood, particle board, wood board such as MDF (medium density fiber board), plaster board such as gypsum board, gypsum slag board, calcium silicate board, asbestos slate board. , Lightweight foamed concrete board, cement board such as hollow extruded cement board, pulp cement board, asbestos cement board, fiber cement board such as wood chip cement board, ceramics board such as ceramics, porcelain, stoneware, earthenware, glass, firewood, iron plate, Galvanized steel plate, polyvinyl chloride sol coated steel plate, aluminum plate, copper plate and other metal plates, polyolefin resin plate, acrylic resin plate, ABS resin plate, polycarbonate plate and other thermoplastic resin plates, phenol resin plate, urea resin plate, unsaturated Thermosetting resin plates such as polyester resin plates, polyurethane resin plates, epoxy resin plates, melamine resin plates, phenolic resins, So-called FRP in which a resin such as a base resin, an unsaturated polyester resin, a polyurethane resin, an epoxy resin, a melamine resin, or a diallyl phthalate resin is impregnated and cured on a glass fiber nonwoven fabric, fabric, paper, or other various fibrous base materials. Examples thereof include a resin plate such as a plate. Moreover, as a base material for decorative boards, you may use the composite base material which laminated | stacked 2 or more types of the said various base materials by well-known means, such as an adhesive agent and heat sealing | fusion.

  Further, the substrate 11 may be subjected to a treatment such as forming a primer layer, or a coating for adjusting the color or a pattern from a design viewpoint may be formed in advance. As the substrate 11 to be an adherend, plate materials of various materials, plate materials such as curved plates, or three-dimensional articles (molded products) in which the above materials are used alone or in combination are targeted.

  A backing material such as Japanese paper, Western paper, synthetic paper, non-woven fabric, woven fabric, cold paper, impregnated paper, synthetic resin sheet or the like may be attached to the decorative sheet 1 of the present invention. By sticking the backing material, the decorative sheet 1 itself can be reinforced, the decorative sheet 1 can be prevented from cracking or breaking, and the adhesive can be prevented from exuding on the surface of the decorative sheet 1, thereby preventing the occurrence of defective products. In addition, the handling becomes easy and the productivity can be improved.

In this way, the substrate 11 on which the decorative sheet 1 is placed every leaf or continuously via the substrate adhesive layer 10 is applied to the cold press, hot press, roll press, laminator, wrapping, edge pasting machine, vacuum The decorative sheet 1 is adhered to the substrate surface by using a sticking device such as a press to form a decorative board.
The decorative board manufactured as described above can be subjected to arbitrary decoration such as grooving and chamfering on the surface and the end of the mouth using a cutting machine such as a router or a cutter.

The adhesive constituting the substrate adhesive layer 10 is applied using a coating device such as a spray, a spreader, or a bar coater. For this adhesive, ethylene-vinyl acetate resin-based, vinyl acetate resin-based, urea resin-based, melamine resin-based, phenolic resin-based, isocyanate-based, urethane resin-based adhesives, etc., alone or in any mixed mixture Used as a mold adhesive. As needed, talc, calcium carbonate, clay, titanium white and other inorganic powders, wheat flour, wood flour, plastic powder, coloring agents, insect repellents, fungicides and the like can be added and mixed in the adhesive. . In general, the adhesive is applied to the substrate surface with a solid content of 35 to 100% by mass and a coating amount in the range of ^{20 to} 300 g / m ² .
Adhesion of the decorative sheet 1 on the substrate 11 is usually performed by forming the adhesive layer 10 for the substrate on the back surface of the decorative sheet 1 of the present invention and attaching the substrate 11 or applying an adhesive on the substrate 11. By the method of sticking the decorative sheet 1 or the like.

The present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.
<Evaluation method>
The decorative sheet obtained in each example was evaluated by the following methods.
(1) Glass transition temperature Tg (° C)
It measured based on JISK7121-1987. Specifically, a differential scanning calorimeter (DSC) is used to hold the adhesive specimen in advance at a temperature approximately 50 ° C. lower than the transition temperature until the device is stabilized, and then the temperature is increased at a heating rate of 20 ° C./min. The DSC curve was measured by heating to a temperature about 30 ° C. higher than the end of the transition, and the glass transition temperature Tg was determined by the method described in JIS K7121-1987.
(2) Initial hardness Each adhesive was solidified in a container to obtain a 10 mm thick specimen. Next, after leaving in a 120 ° C. environment for 2 minutes, taking it out in a 23 ° C. environment and leaving it to stand for 10 minutes to completely cool it, the adhesive was applied with a durometer (according to JIS K 6253: 2006). Hardness was measured. The range of hardness 10 to 90 is type A durometer, the range of hardness over 90 is type D durometer, the range of hardness less than 20 is necessary, the range of hardness less than 10 is type E durometer, if necessary. It was measured.

(3) Suitability for use (adhesion)
The surface protective layer was cross-cut, and Nichiban-made cello tape (registered trademark) was applied, and the operation of abrupt peeling was performed once. The presence or absence of peeling of the coating film was confirmed by visual observation and evaluated according to the following criteria.
A: There is no peeling of the coating film.
○: Very slight coating peeling is confirmed, but there is no problem in actual use.
○: Slight coating film peeling is confirmed, but there is no problem in actual use.
X: The coating film peeled entirely.
XX: Cohesive failure occurs in the adhesive layer.
(4) Designability (surface shapeability)
Each decorative sheet and decorative sheet were placed under a three-wavelength region fluorescent lamp (manufactured by Panasonic Corporation: trade name “FPL27EX-N”), and the reflected image on the surface was visually evaluated according to the following criteria. .
A: The image is clearly reflected.
○: Although not clear, an image is reflected.
○ △: Some roughness of the image is confirmed, but there is no problem in actual use.
×: The image is very rough.

(5) Workability Lapping was performed on 3R-shaped MDF (thickness 3 mm, according to JIS A 5905), and the surface condition after processing was evaluated according to the following criteria.
A: No cracks or floats occur in the surface protective layer at the lapping part.
○: Cracks and floats are generated in the surface protective layer in the lapping part, but there is no problem in actual use.
○: Cracks and floats are slightly generated in the surface protective layer at the lapping part, but there is no problem in actual use.
X: Cracks, floats, etc. occur in the surface protective layer at the lapping processed part.

Example 1
The decorative sheet of Example 1 was produced according to the following steps (a) to (c).
(A) Gravure printing on a polypropylene resin sheet (thickness 150 μm) as a base material with an ink mainly composed of a urethane resin and containing titanium oxide as a coloring pigment so that the thickness after drying becomes 2 μm. Thus, a colored hiding layer was formed. Next, a picture layer was formed as a colored layer on the colored masking layer.
(B) An ionizing radiation curable resin composition (bifunctional urethane acrylate oligomer, weight average molecular weight: 3000) on a polyethylene terephthalate film (trade name “A4100”, manufactured by Toyobo Co., Ltd., thickness 50 μm) as a transfer film. Was applied so as to have a thickness of 5 μm, and cured with an electron beam at 165 kV and 5 Mrad to form a surface protective layer.
(C) The surface of the surface protective layer obtained in the above (b) is subjected to corona treatment, and an acrylic adhesive (glass transition temperature Tg: −20 ° C., initial hardness: 50) is used as a heat seal adhesive on the treated surface. ) Was applied at a temperature of 110 to 120 ° C. so that the adhesive layer and the colored layer of (a) were in contact with each other, to prepare a decorative sheet.

<How to make a decorative board>
On one side of the substrate (thickness: 3 mm, medium density fiberboard (MDF), according to JIS A 5905), ethylene-vinyl acetate resin adhesive (aqueous emulsion type, manufactured by Chuo Rika Co., Ltd., trade name) “BA-20”) was applied so that the coating amount was 60 g / m ² (wet), and the back side of the decorative sheet and the substrate were bonded to each other through this to prepare a decorative board.
The following various evaluations were performed about the obtained decorative sheet and decorative board. The results are shown in Table 1.

Examples 2-9, Comparative Examples 1-9
As shown in Table 1, the decorative sheet and the makeup were made in the same manner as in Example 1 except that the thickness of the surface protective layer, the type and thickness of the adhesive in the adhesive layer, and the thickness of the base material were changed. A plate was made. The following various evaluations were performed about the obtained decorative sheet and decorative board. The results are shown in Table 1.

As apparent from Table 1, the decorative sheet and decorative plate of Examples 1 to 9 in which the glass transition temperature Tg and initial hardness of the adhesive constituting the adhesive layer, and the thickness of each layer satisfy the provisions of the present invention. It can be seen that the cosmetic sheet has all the suitability for use (adhesion), specularity and processability.
On the other hand, the decorative sheets and decorative plates of Comparative Examples 1 to 9 that do not satisfy all the properties of the adhesive layer and the thicknesses of the respective layers defined in the present invention are suitable for use (adhesion), specularity, and processability of the decorative sheet. One of them is low.

  The decorative sheet of the present invention and the decorative board having the same are used in various applications, for example, interior or exterior materials of buildings such as walls, ceilings, floors, window frames, doors, handrails, skirting boards, surrounding edges, and moldings. It can be used for surface decorative panels for joinery, peripheral products for kitchens, furniture or light electrical appliances, surface decorative panels for cabinets such as OA equipment, interiors and exteriors of vehicles.

DESCRIPTION OF SYMBOLS 1 Cosmetic sheet 2 Base material 3 Colored concealment layer 4 Colored layer 5 Adhesive layer 6 Surface protective layer 7 Transfer film 8 Back surface primer layer 10 Adhesive layer 11 for substrates Substrate

Claims (4)

The substrate has at least one layer selected from a colored concealment layer and a colored layer, an adhesive layer, a surface protective layer, and a transfer film in this order, and the thickness of the substrate is 40 μm or more, and the surface The thickness of the protective layer is 2 to 20 μm, the thickness of the adhesive layer is 1 to 18 μm, and the glass transition temperature Tg of the adhesive composing the adhesive layer (conforms to JIS K7121-1987). A decorative sheet, wherein the adhesive sheet has an initial hardness ( durometer hardness according to JIS K 6253: 2006) of 5 to 95.   The decorative sheet according to claim 1, wherein the surface protective layer is made of a cured product of an ionizing radiation curable resin composition, and the ionizing radiation curable resin contains a bifunctional urethane acrylate oligomer.   The decorative sheet according to claim 1 or 2, wherein the transfer film is a polyethylene terephthalate film.   A decorative board comprising the decorative sheet according to claim 1.