JP2007270508A - High-gloss decorative sheet and decorative laminate using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a decorative sheet with a sense of high gloss, which is excellent in stain resistance, marker erasability, surface smoothness and transparency, and which suppresses the offset of silicone, and a decorative laminate in which the sheet and a substrate are joined together. <P>SOLUTION: This decorative sheet, in which a layer obtained by cross-linking and curing an ionizing radiation-curable resin is provided as a surface protecting layer, is characterized in that a polyfunctional silicone acrylate and particulate silica are contained in the ionizing radiation-curable resin. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a decorative sheet having a high gloss feeling and a decorative board obtained by bonding the sheet and a substrate.

As a decorative sheet for furniture and kitchen cabinets, for example, a wood sheet, an inorganic material, a synthetic resin material, a metal sheet such as a steel plate, and a decorative sheet printed with a wood grain pattern, for example, is used as an adhesive. The thing of the structure bonded together by is used.
The decorative sheet used for such a surface decorative plate has appropriate flexibility for secondary processing such as laminating, lapping, and V-cut processing, suitability for processing such as machinability and rupture resistance, and usage conditions. Various properties such as weather resistance, light resistance, heat resistance, water resistance, solvent resistance, surface hardness, abrasion resistance, and scratch resistance are generally required.
In order to satisfy these requirements, a substrate that sufficiently satisfies the above processing suitability is used, and a surface protective layer is applied to the surface of the substrate, and an ionizing radiation curable resin composition is preferably used. Yes. The ionizing radiation curable resin composition is a composition that is cured by ionizing radiation such as ultraviolet rays and electron beams. When the composition is used, the surface protective layer can be applied and formed without a solvent without using an organic solvent. In addition, since the crosslink density can be increased, various advantages such as easy surface strength such as wear resistance can be obtained.

By the way, due to the recent trend toward high-end products by consumers, there is a demand for a high-class feeling for floor tiles, wall panels, furniture, and cabinets for kitchen products. Those having a high-quality appearance are desired. In addition to the above-mentioned properties such as abrasion resistance, chemical resistance, stain resistance, magic erasability, and cellophane tape resistance, which have been generally required in the past, decorative sheet properties include a high-class element. High glossiness and specularity (surface smoothness) are also important. Furthermore, focusing on the manufacturing process of the decorative sheet, it is advantageous from the viewpoint of simplification of the process, quickness, and economical efficiency, as well as the transportation of the decorative plate after manufacturing the decorative sheet. It is also an important factor that it is advantageous in terms of the slipperiness of the plate, that is, it is possible to avoid the risk of falling during storage or transportation by worsening the slipperiness.
Conventionally, as a decorative sheet having a high gloss feeling, a top coat layer is formed by applying a urethane-based paint.
Such urethane-coated paper can be obtained with relatively good surface properties of the coating film, but it may take several days to cure the coating film in the manufacturing process, which is disadvantageous in terms of productivity, and mirror surface There is a problem that it is not always satisfactory in terms of the property (smoothness) and magic erasability (for example, Patent Document 1).
On the other hand, a method of forming a coating film using an ionizing radiation curable resin is also known. For example, after a pattern is printed on a base paper, an electron beam curable resin composition such as an acrylate resin is applied or impregnated. A decorative paper can be rapidly manufactured by irradiating the sheet with an electron beam and curing it (for example, Patent Document 2). However, the conventionally known ionizing radiation curable paint as described above has a problem that it is not always satisfactory in the characteristics of the formed film.

  As mentioned above, in conventional coating compositions for decorative sheets, it is difficult to provide mirror surface properties (smoothness) due to rough surfaces, etc., so stain resistance, cellophane tape release properties, etc. Addition of silicone has been proposed for imparting (for example, Patent Document 3). However, this method improves the stain resistance, cellophane tape-proof release property, etc., but when the decorative sheet is wound up, the silicone floating on the surface of the decorative sheet is transferred to the back surface. There is a problem of transfer. Furthermore, in order to impart these characteristics, a poorly compatible silicone is added to the ionizing radiation curable resin, so that the surface smoothness is poor, the surface opacity is increased, and the sense of quality and design are impaired. Etc., there is room for further improvement.

JP-A-5-92484 Japanese Patent Publication No. 1-55991 Japanese Patent No. 2856862

  Under such circumstances, the present invention has a surface protective layer having an ionizing radiation curable resin that is excellent in surface smoothness and transparency and has a silicone back-off in a decorative sheet having high gloss. It is an object of the present invention to provide a decorative sheet and a decorative sheet obtained by bonding the sheet and a base material.

  As a result of intensive studies to achieve the above object, the inventors of the present invention have simultaneously added silicone and fine particle silica, which are highly compatible with the ionizing radiation curable resin, in the ionizing radiation curable resin forming the surface protective layer. By adding, it was possible to obtain a decorative sheet having a high gloss feeling, excellent stain resistance and magic erasability, excellent surface smoothness and transparency, and silicone back-off.

That is, the present invention
(1) A decorative sheet having a layer obtained by crosslinking and curing an ionizing radiation curable resin as a surface protective layer, the decorative sheet comprising polyfunctional silicone acrylate and fine particle silica in the ionizing radiation curable resin,
(2) The decorative sheet according to (1), wherein the fine particle silica has an average particle size of 1 μm or less.
(3) The decorative sheet according to (1) or (2), wherein the fine particle silica is contained at a ratio of 0.1 to 2.0 parts by mass with respect to 100 parts by mass of the ionizing radiation curable resin.
(4) The decorative sheet according to any one of (1) to (3), wherein the polyfunctional silicone acrylate has a bifunctional or higher functional group, and (5) any one of (1) to (4). A decorative board formed by bonding a substrate via the decorative sheet and an adhesive layer,
Is to provide.

  According to the present invention, in a decorative sheet having a high gloss feeling, it has a high gloss feeling, is excellent in stain resistance and magic erasability, is excellent in surface smoothness and transparency, and suppresses the back-off of silicone. It is possible to provide a decorative sheet having an ionizing radiation curable resin in a surface protective layer and a decorative board in which the substrate and the base material are bonded to each other through an adhesive layer.

The high gloss decorative sheet of the present invention is a decorative sheet having a layer obtained by crosslinking and curing an ionizing radiation curable resin as a surface protective layer, characterized in that it contains polyfunctional silicone acrylate and fine particle silica in the ionizing radiation curable resin. To do.
A typical structure of the high gloss decorative sheet of the present invention will be described with reference to FIG. FIG. 1 is a schematic view showing a cross-section of a decorative sheet 1 of the present invention and a decorative plate in which the decorative sheet is bonded to a substrate. In the example shown in FIG. 1, ionizing radiation containing a uniform and uniform colored layer 6, a pattern layer 7, a uniform and uniform penetration preventing layer 8, a polyfunctional silicone acrylate and fine particle silica covering the entire surface of the substrate 2. A surface protective layer 5 made of a resin obtained by crosslinking and curing a curable resin composition is laminated in this order. The polyfunctional silicone acrylate 4 shown in the figure has a characteristic of being uniformly dispersed in the surface protective layer 5, and the fine particle silica adsorbs a part of the polyfunctional silicone acrylate and floats on the surface layer portion of the surface protective layer 5. Have
The decorative sheet of the present invention can be used as a decorative plate by sticking to various substrates. Specifically, as shown in FIG. 2, the decorative sheet 1 is attached to the substrate 10 via the adhesive layer 9.

Hereinafter, the present invention will be described in detail with reference to FIG. 1 showing one preferred embodiment of the present invention.
The base material 2 used in the present invention is not particularly limited as long as it is usually used as a decorative sheet, such as various papers, plastic films, plastic sheets, metal foils, metal sheets, metal plates, and wood. A wooden board, a ceramic material, etc. can be suitably selected according to a use. Each of these materials may be used alone, but may be a laminate of any combination such as a composite of paper or a composite of paper and a plastic film.
When using these substrates, particularly plastic films or plastic sheets, as a substrate, an oxidation method or a concavo-convex method may be applied to one or both sides as desired in order to improve the adhesion to the layer provided thereon. Physical or chemical surface treatment can be applied.
Examples of the oxidation method include corona discharge treatment, chromium oxidation treatment, flame treatment, hot air treatment, ozone / ultraviolet treatment method, and examples of the unevenness method include a sand blast method and a solvent treatment method. These surface treatments are appropriately selected depending on the type of substrate, but generally, a corona discharge treatment method is preferably used from the viewpoints of effects and operability.
In addition, the base material may be subjected to a treatment such as forming a primer layer for strengthening the interlayer adhesion between the base material and each layer, painting for adjusting the color, or a pattern from a design standpoint. May be formed in advance.

As various papers used as the substrate, thin paper, kraft paper, titanium paper and the like can be used. These paper base materials are made of acrylic resin, styrene butadiene rubber, melamine resin for further strengthening the interlaminar strength between the fibers of the paper base material or to prevent the occurrence of scuffing. Further, a resin such as urethane resin may be added (resin impregnation after paper making, or embedded during paper making). For example, inter-paper reinforced paper, resin-impregnated paper, and the like.
In addition to these, various papers often used in the field of building materials such as linter paper, paperboard, base paper for gypsum board, or a vinyl wallpaper raw material in which a vinyl chloride resin layer is provided on the surface of the paper can be mentioned. Furthermore, coated paper, art paper, sulfate paper, glassine paper, parchment paper, paraffin paper, Japanese paper, or the like used in the office field or normal printing and packaging can also be used. Moreover, although distinguished from these papers, woven fabrics and non-woven fabrics of various fibers having an appearance and properties similar to paper can be used as the base material. Examples of various fibers include inorganic fibers such as glass fibers, asbestos fibers, potassium titanate fibers, alumina fibers, silica fibers, and carbon fibers, or synthetic resin fibers such as polyester fibers, acrylic fibers, and vinylon fibers.

  As a plastic film or a plastic sheet, what consists of various synthetic resins is mentioned. Synthetic resins include 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. Representative examples include 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 66 Examples thereof include polyamide resin, cellulose acetate resin, cellophane, polystyrene resin, polycarbonate resin, polyarylate resin, and polyimide resin.

  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. Examples of the various wood-based boards include wood fiberboards such as wood veneer, plywood, laminated wood, particle board, or MDF (medium density fiberboard). Examples of the ceramic material include ceramic building materials such as gypsum board, calcium silicate board, and wood cement board, ceramics, glass, firewood, and fired tile. 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 can also be used as the base material. .

Although there is no restriction | limiting in particular about the thickness of the base material 2, When using the sheet | seat which uses a plastic as a raw material, thickness is about 20-150 micrometers normally, Preferably it is the range of 30-100 micrometers, and a paper base material is used. When used, the basis weight is usually about ²⁰ to 150 g / m ² , preferably 30 to 100 g / m ² .

The uniform and uniform colored layer 6 covered over the entire surface shown in FIG. 1 is also referred to as a concealing layer or a full surface solid layer provided as desired for the purpose of improving the design of the decorative sheet of the present invention. . The colored layer 6 is formed when the color of the surface of the base material 2 is adjusted so that the base material 2 itself is colored or uneven in color, and gives the intended color to the surface of the base material 2. is there. Usually, it is formed with an opaque color, but it may be formed with a colored transparent color to make use of the pattern of the base. When making use of the fact that the base material 2 is white, or when the base material 2 itself is appropriately colored, it is not necessary to form the colored layer 6.
As the ink used for forming the colored layer, an ink in which 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 appropriately mixed is used. The binder is not particularly limited, and examples thereof include polyurethane resins, vinyl chloride / vinyl acetate copolymer resins, vinyl chloride / vinyl acetate / acrylic copolymer resins, chlorinated polypropylene resins, acrylic resins, and polyesters. Arbitrary resins, polyamide resins, butyral resins, polystyrene resins, nitrocellulose resins, cellulose acetate resins and the like may be used alone or in combination of two or more.
Colorants include carbon black (black), iron black, titanium white, antimony white, yellow lead, titanium yellow, petal, cadmium red, ultramarine, cobalt blue and other inorganic pigments, quinacridone red, isoindolinone yellow, phthalocyanine Organic pigments or dyes such as blue, metallic pigments composed of scaly foil pieces such as aluminum and brass, pearlescent pigments composed of scaly foil pieces such as titanium dioxide-coated mica and basic lead carbonate, and the like are used.
The colored layer 6 is preferably a so-called solid print layer having a thickness of about 1 to 20 μm.

The pattern layer 7 shown in FIG. 1 gives decorativeness to the base material 2 and is formed by printing various patterns using ink and a printing machine. As patterns, there are stone patterns imitating the surface of rocks such as wood grain patterns, marble patterns (for example, travertine marble patterns), fabric patterns imitating cloth or cloth patterns, tiled patterns, brickwork patterns, etc. There are also patterns such as marquetry and patchwork that combine these. These patterns are formed by multicolor printing with the usual yellow, red, blue and black process colors, as well as by multicolor printing with special colors prepared by preparing the individual color plates that make up the pattern. Is done.
As the pattern ink used for the pattern layer 7, the same ink as that used for the colored layer 6 can be used.

  The penetration preventing layer 8 shown in FIG. 1 is a layer provided as desired, and has a function of suppressing the penetration of the ionizing radiation curable resin constituting the surface protective layer 5 into the substrate 2. In particular, this is particularly effective when the substrate 2 is a permeable substrate such as paper or nonwoven fabric. Therefore, the penetration preventing layer 8 may be located between the base material 2 and the surface protective layer 5, for example, between the base material 2 and the colored layer 6, between the colored layer 6 and the pattern layer 7, or shown in FIG. 1. Thus, it is provided between the pattern layer 7 and the surface protective layer 5. Normally, a uniform and uniform layer obtained by crosslinking and curing a curable resin, which has adhesiveness with the ionizing radiation curable resin constituting the surface protective layer 5, is formed of a pattern layer 7 and a surface protective layer 5 as shown in FIG. Provide between. As a result, when the colored layer 6, the pattern layer 7, etc. are present on the substrate 2, these surfaces are smoothed and the function of improving the adhesion between them and the surface protective layer 5 is also achieved. is there.

Next, the surface protective layer 5 is obtained by crosslinking and curing the ionizing radiation curable resin composition as described above, and the ionizing radiation curable resin is composed of a polyfunctional silicone acrylate and fine particle silica. Here, the ionizing radiation curable resin composition is one having an energy quantum capable of crosslinking and polymerizing molecules in an electromagnetic wave or a charged particle beam, that is, crosslinking or curing by irradiating ultraviolet rays or electron beams. Refers to a resin composition.
The original purpose of this surface protective layer, that is, the purpose of providing a conventional surface protective layer, is to have chemical surface properties (contamination resistance, chemical resistance, cellophane tape resistance, etc.) and mechanical properties (scratch resistance, abrasion resistance). Property etc.) depending on the application. Conventionally, silicone methacrylate has been used to improve stain resistance and cellophane tape resistance, but this has caused a problem of silicone set-off. Therefore, in the present invention, by using a resin containing polyfunctional silicone acrylate and fine particle silica as the ionizing radiation curable resin of this surface protective layer, in addition to the above-mentioned purpose of providing a conventional surface protective layer, further contamination resistance It is possible to obtain a decorative sheet having excellent properties and magic erasability, excellent surface smoothness and transparency, and suppressing silicone back-off. The polyfunctional silicone acrylate contained in the ionizing radiation curable resin of the surface protective layer mainly imparts to the decorative sheet the characteristics of improving the surface smoothness, transparency and silicone back-off.

As the polyfunctional silicone acrylate used for the silicone acrylate 4, conventionally known ones can be used. The organic group is an acrylic group, and the organic group is plural (bifunctional or more), preferably 4 or more, more preferably 6 The modified silicone oil is not particularly limited. The structure of the modified silicone oil is roughly divided into a side chain type, a both-end type, a single-end type, and a side-chain both-end type depending on the bonding position of the organic group to be substituted. There is no particular limitation.
Such a silicone acrylate has a molecular weight of 3000 to 100,000, more preferably 10,000 to 30000, and a functional group equivalent (molecular weight / number of functional groups) of 750 to 25000, more preferably from the viewpoint of increasing compatibility with the ionizing radiation curable resin. What has the conditions of 3000-6000 is used.
Content of the said polyfunctional silicone acrylate is 1-5 mass parts with respect to 100 mass parts of ionizing radiation-curable resins from a viewpoint of maintaining transparency, More preferably, it is 1-2 mass parts.

The fine-particle silica has a characteristic that it adsorbs a part of the polyfunctional silicone acrylate and floats on the surface layer portion of the surface protective layer 5 as described above. The polyfunctional silicone acrylate has a feature of being uniformly dispersed in the surface protective layer 5, but is adsorbed on the fine particle silica and floats on the surface layer portion of the surface protective layer, so that the stain resistance and magic erasability of the decorative sheet of the present invention are increased. Etc. are improved.
The particle shape of the fine particle silica used in the present invention includes a sphere, an ellipsoid, a polyhedron, a scale shape, and the like, and is not particularly limited, but a spherical shape is preferable. The average particle diameter of the fine particle silica is preferably 1 μm or less, and more preferably 0.1 μm or less. The lower limit of the average particle size is not particularly limited, but is 0.03 μm for manufacturing reasons. The content of the fine particle silica is 0.1 to 2.0 parts by mass, more preferably 0 with respect to 100 parts by mass of the ionizing radiation curable resin, from the viewpoint of sufficiently adsorbing the polyfunctional silicone acrylate and maintaining transparency. .5 to 1.0 part by mass.

As the ionizing radiation curable resin used for the surface protective layer 5, a conventionally known compound may be appropriately used. Specifically, it can be appropriately selected from polymerizable monomers, polymerizable oligomers or prepolymers conventionally used as ionizing radiation curable resin compositions.
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. 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. Specifically, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) ) Acrylate, polyethylene glycol di (meth) acrylate, hydroxypivalate neopentyl glycol di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dicyclopentenyl di (meth) acrylate, ethylene oxide modified diphosphate ( (Meth) acrylate, allylated cyclohexyl di (meth) acrylate, isocyanurate di (meth) acrylate, trimethylolpropane tri (meth) acrylate, ethylene oxide modified trimethylo Propane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified trimethylolpropane tri (meth) acrylate, tris ( (Acryloxyethyl) isocyanurate, propionic acid modified dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ethylene oxide modified dipentaerythritol hexa (meth) acrylate, caprolactone modified dipentaerythritol hexa (meth) acrylate, Examples include ethylene oxide-modified bisphenol A diacrylate. These polyfunctional (meth) acrylates may be used singly or in combination of two or more.

  In the present invention, a monofunctional (meth) acrylate can be used in combination with the polyfunctional (meth) acrylate as long as the object of the present invention is not impaired, for the purpose of lowering the viscosity. Examples of monofunctional (meth) acrylates include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl ( Examples include meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, and isobornyl (meth) acrylate. These monofunctional (meth) acrylates may be used alone 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.

  Furthermore, other polymerizable oligomers include polybutadiene (meth) acrylate oligomers with high hydrophobicity that have (meth) acrylate groups in the side chain of polybutadiene oligomers, and silicone (meth) acrylate oligomers that have 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 novolac type epoxy resin, bisphenol type epoxy resin, aliphatic vinyl ether, aromatic vinyl ether, etc. There are oligomers having a cationic polymerizable functional group.

When an ultraviolet curable resin composition is used as the ionizing radiation curable resin composition, it is desirable to add about 0.1 to 5 parts by mass of the photopolymerization initiator with respect to 100 parts by mass of the resin composition. The initiator for photopolymerization can be appropriately selected from those conventionally used and is not particularly limited. For example, for a polymerizable monomer or polymerizable oligomer having a radically polymerizable unsaturated group in the molecule. Benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2 -Phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propane-1 - 4- (2-hydroxyethoxy) phenyl-2 (hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4′-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2 -Tertiary butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethyl ketal, acetophenone dimethyl ketal It is done.
Examples of the polymerizable oligomer having a cationic polymerizable functional group in the molecule include aromatic sulfonium salts, aromatic diazonium salts, aromatic iodonium salts, metallocene compounds, and benzoin sulfonic acid esters.
Moreover, as a photosensitizer, p-dimethylbenzoic acid ester, tertiary amines, a thiol type sensitizer, etc. can be used, for example.
In the present invention, it is preferable to use an electron beam curable resin composition as the ionizing radiation curable resin composition. This is because the electron beam curable resin composition can be made solvent-free, is more preferable from the viewpoint of environment and health, and does not require a photopolymerization initiator and can provide stable curing characteristics.

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 cured resin layer obtained. 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, and as the inorganic ultraviolet absorber, titanium dioxide, cerium oxide, zinc oxide or the like having an average particle diameter of about 5 to 120 nm can be preferably used. Moreover, as an organic type ultraviolet absorber, benzotriazole type, for example, 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-3,5-di-tert-) is specifically mentioned. 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. Further, 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.

In the present invention, a polymerizable monomer, a polymerizable oligomer and various additives, which are the ionizing radiation curable components, are uniformly mixed at predetermined ratios to prepare a coating liquid composed of an ionizing radiation curable resin composition. To do. 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 surface of the substrate by a coating method described later.
In the present invention, the coating liquid prepared in this way is applied to the surface of the substrate so that the thickness after curing is 1 to 20 μm, gravure coating, bar coating, roll coating, reverse roll coating, Coating is performed by a known method such as comma coating, preferably gravure coating, to form an uncured resin layer. When the thickness after curing is 1 μm or more, a cured resin layer having a desired function is obtained. The thickness of the surface protective layer after curing is preferably about 2 to 20 μm.

In the present invention, the uncured resin layer thus formed 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 electron beam irradiation, the transmission capability increases as the acceleration voltage increases. Therefore, when using a base material that deteriorates due to the electron beam as the base material, the transmission depth of the electron beam and the thickness of the resin layer are substantially equal. By selecting the accelerating voltage so as to be equal to each other, it is possible to suppress the irradiation of the electron beam to the base material, and to minimize the deterioration of the base material due to the excessive electron beam.
The irradiation dose is preferably such that the crosslink 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 50 kGy (1 to 5 Mrad).
Further, the electron beam source is not particularly limited. For example, various electron beam accelerators such as a cockroft Walton type, a bandegraft type, a resonant transformer type, an insulated core transformer type, a linear type, a dynamitron type, and a high frequency type. 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 also be imparted.

The decorative sheet of the present invention can be used as a decorative plate by sticking to various substrates. Specifically, as shown in FIG. 2, the decorative sheet 1 is attached to the substrate 10 via the adhesive layer 9.
The board | substrate used as a to-be-adhered body is not specifically limited, A plastic board, a metal board, woody board | plates, such as a timber, a ceramic material, etc. can be selected suitably according to a use. When these substrates, particularly plastic sheets, are used as substrates, physical or chemical surface treatment such as oxidation or unevenness is optionally applied on one or both sides to improve adhesion to the decorative sheet. Can be applied.
Examples of the oxidation method include corona discharge treatment, chromium oxidation treatment, flame treatment, hot air treatment, ozone / ultraviolet treatment method, and examples of the unevenness method include a sand blast method and a solvent treatment method. These surface treatments are appropriately selected depending on the type of substrate, but generally, a corona discharge treatment method is preferably used from the viewpoints of effects and operability.

  As a plastic sheet, what consists of various synthetic resins is mentioned. Synthetic resins include 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. Representative examples include 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 66 And polyamide resin, cellulose triacetate resin, cellophane, polystyrene resin, polycarbonate resin, polyarylate resin, polyimide resin, and the like.

As 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.
Examples of wood-based boards include veneer of various materials such as cedar, firewood, firewood, pine, lawan, teak and melapie, and wood materials such as wood veneer, wood plywood, particle board, and medium density fiber board (MDF). . These can be used alone or in a laminated manner. The wooden board includes not only a wooden board but also a plastic board containing paper powder and reinforced paper having strength.
Examples of the ceramic material include ceramic building materials such as a gypsum plate, a calcium silicate plate, and a wood piece cement plate, ceramics, glass, firewood, fired tiles, plates made mainly of volcanic ash, and the like.
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 can also be used as the base material. .

  Further, the substrate 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 a substrate to be an adherend, plate materials such as flat plates and curved plates of various materials, or three-dimensional shaped 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. By sticking the backing material, the effect of reinforcing the decorative sheet itself, preventing cracking and tearing of the decorative sheet, preventing the adhesive from exuding on the surface of the decorative sheet, and preventing the occurrence of defective products, Handling becomes easy and productivity can be improved.

  Thus, a substrate on which a decorative sheet is placed every leaf or continuously via an adhesive is attached to a cold press, a hot press, a roll press, a laminator, a lapping, an edge pasting machine, a vacuum press, etc. The decorative sheet is bonded to the substrate surface by pressing with an apparatus to obtain a decorative plate.

The adhesive is applied using an application device such as a spray, spreader, or bar coater. As the adhesive, vinyl acetate resin-based, urea resin-based, melamine resin-based, phenol resin-based, isocyanate-based adhesives, etc., are used alone or as a mixed adhesive obtained by arbitrarily mixing them. 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 80% by mass and an application amount of 50 to 300 g / m ² .
Adhesion of the decorative sheet on the substrate is usually performed by forming an adhesive layer on the back surface of the decorative sheet of the present invention and adhering the substrate or applying an adhesive on the substrate and adhering the decorative sheet. Etc.

  The decorative board manufactured as described above is also optionally cut by the decorative board, and optionally decorated such as grooving and chamfering on the surface and the mouth using a cutting machine such as a router or a cutter. Can be applied. And various uses, for example, interior or exterior materials of buildings such as walls, ceilings, floors, window frames, doors, handrails, skirting boards, margins, surface decorative boards for fittings such as malls, kitchens, furniture or light electrical appliances, It can be used for surface decorative boards of cabinets such as OA equipment, interiors and exteriors of vehicles.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by this example.
(Evaluation methods)
The decorative sheet obtained in each example was evaluated by the following methods.
(1) Evaluation of Gloss Using a gloss meter (“micro-TRI-gloss” manufactured by Gardner), gloss values in a high gloss region and a low gloss region were measured under the condition of an incident angle of 75 degrees. The higher the number, the higher the gloss (high gloss), and the lower the number, the lower the gloss (low gloss).
(2) Setback The front and back of the decorative sheets obtained in the examples and comparative examples were overlapped and cured for 72 hours under the conditions of 60 ° C. and 1 kg / cm 2, and the subsequent wetting of the back side of the decorative sheet was measured according to JIS K6768. The wettability was evaluated.
(3) Oil-based magic wiping property After filling in the coated surface with oil-based magic ink, wipe off with gauze after 3 minutes and visually evaluate the product made by erasure.
○ No ink traces △ Ink traces are slight but have no problem in practical use × Ink traces remain remarkable (4) Cellophane tape resistance (peel strength test)
A cellophane tape (cellophane adhesive tape made by Nichiban Co., Ltd., “Cerotape (registered trademark)” 25 mm width) is strongly adhered to the surface of the cosmetic material obtained in the examples and comparative examples at room temperature. The cellophane tape was forcibly peeled from the surface in the direction of 90 degrees, and the peel strength at this time was measured using a peel strength measuring device (“peel tester” manufactured by Instruments Inc.).

Example 1
As the base material 2, a reinforced paper between building materials with a weight of 30 g / m ² of rice is used, and an acrylic resin and nitrified cotton are used as a binder on one side, and an ink containing titanium white, petal, and chrome is used as a colorant, A (full surface) layer having a coating amount of 3 g / m ² was applied by gravure printing to form a colored layer 6. A woodgrain pattern layer 7 was formed by gravure printing using an ink containing nitrified cotton as a binder and a colorant mainly composed of a petiole.
Subsequently, using a coating composition having a polyisocyanate composed of a polyester urethane resin having a number average molecular weight of 20,000 and a glass transition temperature (Tg) of 59.8 ° C. and tolylene diisocyanate, a coating amount of 2 g / m. ² and gravure printing was performed on the entire surface to form a permeation preventive layer 8 (primer layer).
On these ink layers, 97.5 parts by mass of urethane acrylate, 2 parts by mass of bifunctional silicone acrylate (manufactured by Shin-Etsu Chemical Co., Ltd., functional group equivalent: about 4000), and 0.5 mass of fine particle silica having an average particle size of 0.5 μm The electron beam curable resin composition consisting of parts was applied by a gravure offset coater method at a coating amount of 13 g / m ² . After the coating, an electron beam with an acceleration voltage of 175 kV and an irradiation dose of 50 kGy (5 Mrad) was irradiated to cure the electron beam curable resin composition to obtain the surface protective layer 5. Next, curing was performed at 70 ° C. for 24 hours to obtain a decorative sheet.
The decorative sheet was evaluated for gloss, haze, set-off, oil-based magic wipe-off property and cellophane tape resistance. The results are shown in Table 1.
In addition, the back side of the decorative sheet and the lauan plywood 10 having a thickness of 2.5 mm as a substrate are applied to the wood plywood with an ethylene / vinyl acetate adhesive “BA-820” which is an aqueous emulsion manufactured by Chuo Rika Co., Ltd. Adhesion was carried out through an adhesive layer formed by coating under the condition of an amount of 60 g / m ² (wet) to produce a wood decorative board.

Example 2
A decorative sheet was obtained in the same manner as in Example 1 except that the surface protective layer 5 described in Example 1 was changed to 0.3 parts by mass of fine-particle silica. The evaluation results are shown in Table 1.
Further, in the wooden decorative board described in Example 1, in place of using the decorative sheet prepared in Example 1, the wooden decorative sheet was prepared in the same manner as in Example 1 except that the decorative sheet prepared in Example 2 was used. I got a plate.

Comparative Example 1
In the surface protective layer 5 described in Example 1, a decorative sheet was obtained in the same manner as in Example 1 except that 2 parts by mass of monofunctional silicone methacrylate was used instead of using bifunctional silicone acrylate. The evaluation results are shown in Table 1.
Further, in the wooden decorative board described in Example 1, instead of using the decorative sheet prepared in Example 1, a wooden decorative material was prepared in the same manner as in Example 1 except that the decorative sheet prepared in Comparative Example 1 was used. I got a plate.

Comparative Example 2
In the surface protective layer 5 described in Example 1, instead of using bifunctional silicone acrylate, 2 parts by mass of monofunctional silicone methacrylate was used, and instead of using 0.5 parts by mass of fine-particle silica, 3 parts by mass were used. A decorative sheet was obtained in the same manner as in Example 1 except that. The evaluation results are shown in Table 1.
Further, in the wooden decorative board described in Example 1, instead of using the decorative sheet prepared in Example 1, the wooden decorative sheet was prepared in the same manner as in Example 1 except that the decorative sheet prepared in Comparative Example 3 was used. I got a plate.

  The decorative sheets obtained in Examples 1 and 2 showed high performance in all points of gloss evaluation, set-off, oil-based magic wipe-off property and cellophane tape resistance. On the other hand, in Comparative Examples 1 and 2 in which no silicone acrylate was used, a decorative sheet satisfying all the performances was not obtained.

  According to the present invention, in a decorative sheet having a high gloss feeling, the decorative sheet is excellent in stain resistance and magic erasability, excellent in surface smoothness and transparency, and suppresses the silicone back-off, and the sheet and the base. A decorative board in which a substrate is bonded to a material via an adhesive layer can be obtained.

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 of this invention.

Explanation of symbols

1. Cosmetic sheet Base material 3. Silicone acrylate 4. 4. Fine particle silica Surface protective layer 6. 6. Colored layer Picture layer 8. 8. Penetration preventing layer Adhesive layer 10. substrate

Claims (5)

  A decorative sheet having a layer obtained by crosslinking and curing an ionizing radiation curable resin as a surface protective layer, comprising a polyfunctional silicone acrylate and fine particle silica in the ionizing radiation curable resin.   The decorative sheet according to claim 1, wherein the fine particle silica has an average particle size of 1 μm or less.   The decorative sheet according to claim 1 or 2, wherein the fine particle silica is contained at a ratio of 0.1 to 2.0 parts by mass with respect to 100 parts by mass of the ionizing radiation curable resin.   The decorative sheet according to any one of claims 1 to 3, wherein the polyfunctional silicone acrylate has a bifunctional or higher functional group.   A decorative board comprising a decorative sheet according to any one of claims 1 to 4 and a substrate bonded via an adhesive layer.

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