JP4600676B2 - Decorative sheet - Google Patents

Description

  The present invention relates to a decorative sheet.

  The decorative sheet is used by sticking on the surface of the adherend for the purpose of protecting the surface of the adherend such as a wooden board, decoration, and the like. A decorative board obtained by attaching a decorative sheet to an adherend is used for various building materials, furniture, and the like.

  It is desirable that the outermost surface layer of the decorative sheet has a high surface strength. Conventionally, attempts have been made to form the outermost surface layer with a curable resin. For example, Patent Document 1 is a decorative sheet in which a pattern layer is provided on at least one surface of a base sheet, and a protective layer made of an ionizing radiation curable resin is provided on the surface, and in the ionizing radiation curable resin, A decorative sheet comprising an ionizing radiation reaction type weathering additive is disclosed. The curable resin layer is often laminated on various primer layers.

  Conventionally, such a decorative sheet is formed from a solvent-based composition containing an aromatic solvent such as toluene and xylene, and an aliphatic solvent such as methyl ethyl ketone and ethyl acetate, as shown in Patent Document 2, for example.

All of the above-mentioned aromatic solvents and aliphatic solvents are organic volatile substances (VOC). In particular, aromatic solvents such as toluene and xylene are formulated as guidelines for designated chemical substances in the PRTR Law and chemical substances in indoor air. Listed as a substance. In addition, problems in the working environment due to volatilization of VOC contained in the solvent-based coating agent at the time of manufacturing the decorative sheet, environmental safety problems in which the residual VOC at the time of using the decorative sheet is diffused into a general living space, etc. Yes. Therefore, reducing the amount of VOC used in the decorative sheet has become a recent issue. It is preferable to form the primer layer from an aqueous composition from the viewpoint of VOC reduction. However, when formed from an aqueous composition, the physical properties tend to be lower than when formed from a solvent-based composition.
Japanese Patent Application Laid-Open No. 11-334021 JP-A-11-198309

  An object of the present invention is to provide a decorative sheet in which a curable resin layer is laminated on a primer layer made of an aqueous composition, and the physical properties of the primer layer are good.

  As a result of intensive studies, the present inventor has found that a primer layer formed from a specific aqueous composition can achieve the above object, and has completed the present invention.

  That is, the present invention relates to the following decorative sheet.

1. A decorative sheet having a curable resin layer on the outermost surface,
The curable resin layer is laminated on a primer layer made of an aqueous composition containing an acrylic-urethane copolymer and isocyanate ,
The acrylic-urethane copolymer can be obtained by reacting at least acrylic polyol, polyester polyol, hydroxycarboxylic acid and diisocyanate,
The copolymerization ratio of the acrylic polyol and the polyester polyol is 40:60 to 60:40 in order by weight.
Makeup sheet .
2. Item 2. The decorative sheet according to Item 1, wherein the acrylic-urethane copolymer has an acid value of 20 mgKOH / g or more.
3. Item 3. The decorative sheet according to Item 1 or 2, wherein the isocyanate is a self-emulsifying isocyanate.
4). 4. The decorative sheet according to item 3, wherein the self-emulsifying isocyanate is a mixture of isocyanurate-modified polyisocyanate and allophanate group-containing polyisocyanate.
5). The decorative sheet according to Item 4, wherein the weight ratio of the isocyanurate-modified polyisocyanate and the allophanate group-containing polyisocyanate is 40:60 to 60:40 in order.
6). Item 6. The decorative sheet according to any one of Items 1 to 5, wherein the polyester polyol contains an adipate polyester polyol and a phthalate polyester polyol in a weight ratio of 50:50 to 70:30 in this order.
7). Item 7. The decorative sheet according to any one of Items 1 to 6, wherein the aqueous composition contains 20 to 60 parts by weight of isocyanate with respect to 100 parts by weight of the acrylic-urethane copolymer.
8). Item 8. The decorative sheet according to any one of Items 1 to 7, wherein the curable resin layer is an ionizing radiation curable resin layer.
9. A decorative board obtained by laminating the decorative sheet according to any one of Items 1 to 8 and an adherend.
10. A primer layer for laminating a curable resin layer, comprising an aqueous composition containing an acrylic-urethane copolymer and isocyanate,
The acrylic-urethane copolymer can be obtained by reacting at least acrylic polyol, polyester polyol, hydroxycarboxylic acid and diisocyanate,
The copolymerization ratio of the acrylic polyol and the polyester polyol is 40:60 to 60:40 in order by weight.
Primer layer.

Below, it will be described in detail the decorative sheet of the present invention.

  The decorative sheet of the present invention is a decorative sheet having a curable resin layer (preferably an ionizing radiation curable resin layer) on the outermost surface, and the curable resin layer includes an aqueous composition containing an acrylic-urethane copolymer and an isocyanate. It is laminated | stacked on the primer layer which consists of a thing.

  Since the decorative sheet of the present invention has the primer layer, the weather resistance adhesion and solvent resistance adhesion of the curable resin layer are good. In addition, the primer layer has a good surface condition (no spots, streaks, etc.) and excellent recoatability, and a curable resin layer can be satisfactorily formed even after a lapse of time from the formation of the primer layer.

Primer layer The primer layer of the present invention is provided to form a curable resin layer thereon.

  The primer layer is formed from an aqueous composition containing an acrylic-urethane copolymer and an isocyanate. In addition, the isocyanate contained in the aqueous composition is referred to as a curing agent, and the other components are referred to as a main agent.

  An aqueous acrylic-urethane copolymer is used as the acrylic-urethane copolymer. The aqueous acrylic-urethane copolymer can be obtained, for example, by neutralizing free carboxylic acid contained in the copolymer with various neutralizing agents (alkanolamine, sodium hydroxide, etc.).

  In the present invention, the acid value of the acrylic-urethane copolymer is preferably 20 mgKOH / g or more. The acid value is more preferably 40 mgKOH / g or more, and the upper limit is not limited, but is about 60 mgKOH / g. By setting the acid value to 20 mgKOH / g or more, the particle diameter of the acrylic-urethane copolymer present in the form of fine particles in the aqueous composition can be reduced. The stability of the object can be improved. The particle size of the copolymer is not limited, but is preferably about 70 nm or less. If the particle size of the copolymer is about 50 to 60 nm, the re-solubility of the copolymer and the stability of the aqueous composition are good. It is. The acid value is a value determined from the number of mg of KOH required to neutralize free carboxyl groups contained in 1 g of the solid content of the copolymer in accordance with JIS K0070-1992.

  The method for synthesizing the acrylic-urethane copolymer is not limited, but from the viewpoint of setting the acid value before neutralization to 20 mgKOH / g or more, at least acrylic polyol, polyester polyol, diisocyanate and hydroxycarboxylic acid are reacted. A synthetic method is preferred. The acid value can be adjusted by the amount of hydroxycarboxylic acid. The amount of hydroxycarboxylic acid can be adjusted so that the acid value is preferably 20 mgKOH / g or more. The acrylic-urethane copolymer obtained by the above reaction is used after neutralizing the free carboxylic acid with a neutralizing agent to make it hydrophilic and then extending the chain with a chain extender such as diamine.

  Through the above series of reactions, polyester urethane is generated, and an acrylic polyol is introduced into the molecule to obtain an aqueous acrylic-urethane copolymer having a hydroxyl group at the terminal.

  The copolymer ratio of acrylic polyol and polyester polyol in the copolymer is preferably about 40:60 to 60:40 by weight. Within such a range, blocking properties, recoating properties and the like are improved, which is preferable.

  As the acrylic in the copolymer, a linear acrylic ester polymer having a hydroxyl group at the terminal is used. As such a linear acrylic acid ester polymer, for example, polymethyl methacrylate (PMMA) is preferable, which contributes to improvement of weather resistance.

  The polyol of the urethane component constituting the copolymer is not limited, and examples thereof include polyester polyol, polyether polyol, and polycarbonate polyol. Among these polyols, polyester polyols are preferred when importance is attached to the balance of weather resistance, adhesion, and cost merit.

  Examples of polyester polyols include known adipate polyester polyols such as adipic acid polyester polyols, succinic acid polyester polyols, and sebacic acid polyester polyols, and phthalate polyester polyols such as phthalic polyester polyols, isophthalic polyester polyols, and terephthalic acid polyester polyols. There is. Although it is not limited as a polyester polyol, From the point of adhesiveness and a weather resistance, what contains an adipate type polyester polyol and a phthalate type polyester polyol in the weight ratio of 50: 50-70: 30 in order is preferable.

  The diisocyanate constituting the copolymer is not limited, but alicyclic isocyanate is preferable, and specifically, IPDI (isophorone diisocyanate) is preferable.

  As the hydroxycarboxylic acid constituting the copolymer, 2,2bis (hydroxymethyl) propionic acid is preferably used.

  The isocyanate contained in the aqueous composition is not limited, and examples thereof include known aliphatic isocyanates and alicyclic isocyanates. For example, 1,6-hexamethylene diisocyanate (HDI), 2,2,4 (2,4,4) -trimethylhexamethylene diisocyanate (TMDI), 4,4'-dicyclohexylmethane diisocyanate (HMDI), 1,4- Examples include cyclohexyl diisocyanate (CHDI), isophorone diisocyanate (IPDI), lysine diisocyanate (LDI), hydrogenated tolylene diisocyanate, and hydrogenated diphenylmethane diisocyanate. The isocyanate may be an adduct or multimer of the above isocyanate. In addition, polyisocyanates such as derivatives (adducts) obtained by adding these isocyanates to polyols may be used.

  As described above, although the isocyanate is not limited, self-emulsifying polyisocyanate is suitable, and self-emulsifying polyisocyanate that is a mixture of isocyanurate-modified polyisocyanate and allophanate group-containing polyisocyanate can be suitably used. As the self-emulsifying polyisocyanate, the weight ratio of the isocyanurate-modified polyisocyanate and the allophanate group-containing polyisocyanate is preferably about 40:60 to 60:40 in order.

More specifically, as the self-emulsifying type polyisocyanate, the following (A) and (B);
(A): a polyisocyanate obtained by reacting an isocyanurate-modified polyisocyanate (A1) of hexamethylene diisocyanate with an adduct (A2) containing at least a monool alkylene oxide (containing at least 30 mol% of ethylene oxide),
(B): an allophanate group-containing polyisocyanate having an average number of functional groups of 2 to 3 and a viscosity at 25 ° C. of 500 mPa · s or less,
Self-emulsifying polyisocyanate containing (A) :( B) = 40: 60 to 60:40 by weight ratio can be preferably used.

  The polyisocyanate (A) has water dispersibility, and the pot life when dispersed in water is about 5 to 6 hours. However, since the viscosity is high, the compatibility with the main agent is not so good. On the other hand, polyisocyanate (B) is not water-dispersed by itself, but has a low viscosity. Therefore, by mixing (B) with (A), the compatibility with the main agent is improved. The surface finish is improved. The self-emulsifying type polyisocyanate obtained by mixing the above (A) and (B) at a mass ratio of 40:60 to 60:40 is compatible with the main agent (particularly acrylic-urethane copolymer), coated surface state, pot life. Etc. are good.

  The aqueous composition for forming the primer layer is not limited as long as it is a composition (including a resin solution or a resin emulsion) in which a resin component is dissolved or dispersed in water or an aqueous solvent. In the present invention, a resin emulsion (aqueous resin emulsion) is preferable as the aqueous composition.

  The water that is the solvent can be, for example, industrial water of a grade that is used in known aqueous coating agents.

  Further, as the aqueous solvent, a mixed solvent composed of water and an organic solvent can be used. As the organic solvent, for example, water-soluble organic solvents such as glycols and glycol esters can be suitably used in addition to lower alcohols such as ethanol, isopropyl alcohol, and n-propyl alcohol. The water-soluble organic solvent is used for the purpose of improving the fluidity of the aqueous composition, improving the wettability to the substrate sheet that is the object to be coated, and adjusting the drying property. The type and amount used are determined accordingly. In the case of a mixed solvent, the ratio of water and organic solvent can be appropriately adjusted within the range of water: organic solvent 20:80 to 100: 0 (weight ratio).

  The weight ratio of the acrylic-urethane copolymer and isocyanate in the aqueous composition is not limited, but is preferably about 20 to 60 parts by weight with respect to 100 parts by weight of the acrylic-urethane copolymer.

  The binder in the aqueous composition is preferably anionic, and a basic substance (alkali) is preferably used as a neutralizing agent for functional groups such as a carboxyl group, a sulfonic acid group, and a phosphoric acid group. Examples of the neutralizing agent include ammonia, ethylamine, trimethylamine, triethylamine, triisopropylamine, tributylamine, triethanolamine, N-methyldiethanolamine, N-phenyldiethanolamine, monoethanolamine, dimethylethanolamine, diethylethanolamine, morpholine. Organic amines such as N-methylmorpholine and 2-amino-2-ethyl-1-propanol; alkali metals such as lithium, potassium and sodium; and metal hydroxides such as sodium hydroxide and potassium hydroxide. . Among these, at least one of metal hydroxide and alkanolamine is preferable because it has excellent neutralizing power and can more effectively reduce environmental pollution due to volatilization of organic solvents. In particular, at least one of sodium hydroxide, potassium hydroxide, triethanolamine and triisopropanolamine is preferable.

  What is necessary is just to set the usage-amount of a neutralizing agent suitably in the range of 1-1.1 times the quantity (equivalent) which can fully neutralize the said resin component generally. By setting within this range, desired water resistance and the like can be imparted with more reliable neutralizing power.

  If necessary, extender pigments can be added to the aqueous composition for the purpose of at least one of blocking resistance, improvement of heat resistance during embossing, improvement of adhesive force due to anchor effect, and the like.

  As the extender pigment, known or commercially available pigments can be used, and there is no particular limitation. For example, inorganic pigments such as white clay, talc, clay, diatomaceous earth, calcium carbonate, barium sulfate, titanium oxide, alumina white, silica, kaolin, mica, aluminum hydroxide, polyacrylate, polyurethane, polyester, polyethylene, polypropylene Organic pigments such as polyvinyl chloride, polyvinylidene chloride, polystyrene, polysiloxane, phenol resin, epoxy resin, benzoguanamine resin, or organic pigments composed of these copolymers can be used. These are usually desirably used in the form of particles.

  The aqueous composition may contain a weathering agent in order to improve the weather resistance of the decorative sheet. Examples of weathering agents include ultraviolet absorbers and light stabilizers. Examples of the UV absorber include benzotriazole UV absorbers and triazine UV absorbers. Examples of the light stabilizer include hindered amine light stabilizers (HALS).

Specific structure of decorative sheet As long as the decorative sheet of the present invention has a curable resin layer on the outermost surface and the curable resin layer is laminated on the primer layer, the layer structure is not particularly limited. Examples of the resin component contained in the curable resin layer include thermosetting resins and ionizing radiation curable resins.

  Among the curable resins, as the thermosetting resin, for example, phenol resin, urea resin, diallyl phthalate resin, melamine resin, guanamine resin, unsaturated polyester resin, polyurethane resin (including two-component curable polyurethane), Examples thereof include an epoxy resin, an amino alkyd resin, a melamine-urea cocondensation resin, a silicon resin, and a polysiloxane resin. A curing agent such as a crosslinking agent or a polymerization initiator, or a polymerization accelerator can be added to the resin as necessary. As the curing agent, for example, isocyanate or organic sulfonate can be added to unsaturated polyester resin or polyurethane resin, organic amine or the like can be added to epoxy resin, peroxide such as methyl ethyl ketone peroxide, or azoisobutyl nitrile. Radical initiators such as can be added to the unsaturated polyester. The ionizing radiation curable resin will be described later.

  As a configuration of the decorative sheet, for example, at least a pattern layer, a transparent resin layer, a primer layer, and an ionizing radiation curable resin layer (outermost surface layer) are provided on the base sheet, and the ionizing radiation curable resin layer is the primer layer. A preferred embodiment is a decorative sheet laminated on the substrate.

  The formation method of each layer including the primer layer is not limited. For example, printing such as gravure printing, flexographic printing, silk screen printing, offset printing, transfer printing; application of spray, roller, brush, etc .; molding of sheet-like material, etc. Any of stacked bodies can be adopted. What is necessary is just to select combining suitably from these methods according to the characteristic, raw material, etc. of each layer. Each layer is preferably formed by lamination of a molded body or a coating film made of an aqueous composition.

  The thickness of each layer is not limited, and can be appropriately determined according to the use and characteristics of the final product. Usually, it can be in the range of about 0.1 to 500 μm. In particular, the primer layer is generally desirably about 1 to 10 μm.

  Hereinafter, each layer other than the primer layer will be described using the above embodiment as a representative example.

≪Base material sheet≫
A pattern layer etc. are laminated | stacked one by one on the surface (front surface) of a base material sheet.

  As a base material sheet, what was formed, for example with the thermoplastic resin can be used conveniently. Specifically, polyvinyl chloride, polyethylene terephthalate, polybutylene terephthalate, polyamide, polyethylene, polypropylene, polycarbonate, polyethylene naphthalate, ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / acrylic acid ester copolymer Polymers, ionomers, acrylic esters, methacrylic esters and the like can be mentioned.

  The base material sheet may be colored. In this case, a coloring material (pigment or dye) can be added to the above thermoplastic resin for coloring. As the colorant, for example, inorganic pigments such as titanium dioxide, carbon black and iron oxide, organic pigments such as phthalocyanine blue, and various dyes can be used. These can be selected from one or more known or commercially available ones. Further, the addition amount of the colorant may be appropriately set according to the desired color tone.

  The base sheet contains various additives such as fillers, matting agents, foaming agents, flame retardants, lubricants, antistatic agents, antioxidants, ultraviolet absorbers, and light stabilizers as necessary. May be.

  Although the thickness of a base material sheet can be suitably set with the use of a final product, a usage method, etc., generally it is preferable to set it as 50-250 micrometers.

  In the base material sheet, if necessary, the surface (front surface) can be subjected to corona discharge treatment in order to strengthen the adhesion of the ink for providing the pattern layer. What is necessary is just to implement the method and conditions of a corona discharge process according to a well-known method. Moreover, a corona discharge process can also be given to the back surface of a base material sheet as needed.

≪Backside primer layer of substrate sheet≫
A primer layer may be formed on the back surface of the base sheet in order to improve the adhesion between the decorative sheet and the adherend. Examples of the material for forming the primer layer include polyester resins, polyurethane resins (particularly polyacrylic polyol, polyester polyol, polyether polyol, etc. and isocyanate compounds), acrylic resins, polycarbonate resins, and vinyl chloride. / In addition to resins such as vinyl acetate copolymer, polyvinyl butyral resin and nitrocellulose resin, compounds such as alkyl titanate and ethyleneimine can also be used. Using these as they are or in a state dissolved or dispersed in a solvent, a primer layer can be formed according to a known printing method, coating method or the like.

≪Picture layer≫
The pattern layer can represent not only patterns or patterns of natural materials such as wood grain and joints, but also letters and figures.

  Formation of the pattern layer is preferably carried out by a known printing method such as gravure printing, flexographic printing, silk screen printing, or offset printing, preferably using an ink having excellent adhesion to the base sheet.

  As the ink, an ink containing a colorant and a binder can be generally used. The ink binder may be appropriately selected from known or commercially available products depending on the material of the base sheet. In the present invention, it is desirable to use an aqueous composition as the ink in that the effect of reducing VOC and the like is further enhanced. As the aqueous composition, a composition in which a coloring material is blended in an aqueous binder can be used.

  As the aqueous binder, known or commercially available resin aqueous solutions, aqueous resin emulsions, and the like can be used. Resins used for these aqueous binders include polyester, polyacrylate, polyvinyl acetate, polybutadiene, polyvinyl chloride, chlorinated polypropylene, polyethylene, polystyrene, polystyrene-acrylate in addition to the above-mentioned hydrophilic polyester-based urethane resins. Copolymers, rosin derivatives, alcohol adducts of styrene-maleic anhydride copolymers, cellulose resins, and the like can also be used in combination.

  More specifically, for example, polyacrylamide resins, poly (meth) acrylic resins, polyethylene oxide resins, poly N-vinyl pyrrolidone resins, water-soluble polyester resins, water-soluble polyamide resins, water-soluble amino acids. Also usable are water-based resins, water-soluble phenolic resins, other water-soluble synthetic resins; water-soluble natural polymers such as polynucleotides, polypeptides, polysaccharides, and the like. Further, for example, natural rubber, synthetic rubber, polyvinyl acetate resin, (meth) acrylic resin, polyvinyl chloride resin, polyurethane-polyacrylic resin modified or mixed resin, and other resins can be used. These resins can be used alone or in combination of two or more.

  In addition, (meth) acrylic monomers such as acrylic acid esters, methacrylic acid esters, hydroxyethyl acrylate, hydroxyethyl methacrylate; nitrile monomers such as acrylonitrile and methacrylonitrile; amide monomers such as acrylamide and methacrylamide; amides thereof N-alkoxy substituted monomers and N-methylol substituted monomers; styrene monomers such as styrene, vinyl toluene, α-methyl styrene, divinyl benzene; allylic monomers such as diallyl phthalate, allyl glycidyl ether, triallyl isocyanurate; Monomers having a polymerizable double bond such as vinyl acetate and N-vinyl pyrrolidone; one or more of these, and acrylic acid, methacrylic acid, maleic acid, maleic anhydride having a carboxyl group It is acid, fumaric acid, itaconic acid, also possible to use one type or alkali solution-soluble (meth) acrylic copolymer comprising a copolymer of more unsaturated carboxylic acids other like. These can use 1 type (s) or 2 or more types.

  The colorant is not particularly limited, and a known colorant can be used. For example, titanium white, zinc white, petal, vermilion, ultramarine blue, cobalt blue, titanium yellow, carbon black and other inorganic pigments, isoindolinone, Hansa Yellow A, quinacridone, permanent red 4R, phthalocyanine blue, indanthrene blue RS, Examples thereof include organic pigments (including dyes) such as annin phosphorus black, metal pigments such as aluminum and brass, pearlescent pigments made of foil powder such as titanium dioxide-coated mica and basic lead carbonate, and the like. These can be used alone or in combination of two or more.

≪Adhesive layer≫
The adhesive layer exists between the pattern layer and the transparent resin layer. The adhesive can be appropriately selected from known adhesives according to the components constituting the picture layer or the transparent resin layer. For example, various adhesives such as polyurethane resin, polyacrylic resin, polycarbonate resin, and epoxy resin can be used. In addition to the reactive curing type, any type of adhesive such as a hot melt type, an ionizing radiation curing type, and an ultraviolet curing type may be used.

  What is necessary is just to implement as an adhesion | attachment method according to a well-known method according to the kind etc. of adhesive agent to be used. In the present invention, an adhesive capable of thermocompression bonding is used, and the pattern layer and the transparent resin layer can be laminated by thermocompression bonding.

  The adhesive layer is desirably formed of an aqueous composition in that the effect of reducing VOC is enhanced. As the aqueous composition, a composition containing an aqueous binder can be used. The aqueous binder may be in any form such as an aqueous resin solution or an aqueous resin emulsion. The resin used for these can use the thing similar to the aqueous | water-based binder of the aqueous composition used for formation of the said pattern layer.

  In addition, as needed, well-known easy adhesion processes, such as a corona discharge process, a plasma process, a degreasing process, and a surface roughening process, can also be given to an adhesion surface.

  The thickness of the adhesive layer varies depending on the transparent protective layer, the type of adhesive used, and the like, but generally may be about 0.1 to 30 μm.

≪Transparent resin layer≫
The transparent resin layer may be colored as long as it is transparent. Moreover, it may be translucent as long as the pattern layer is visible.

  Examples of the resin include polyvinyl chloride, polyethylene terephthalate, polybutylene terephthalate, polyamide, polyethylene, polypropylene, ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / acrylic acid ester copolymer, ionomer, Examples thereof include polymethylpentene, acrylic acid ester, methacrylic acid ester, polycarbonate, and cellulose triacetate. The transparent resin layer is particularly preferably a polyolefin resin such as polypropylene. More preferably, it is a polyolefin resin having stereoregularity. When a polyolefin resin is used, it is desirable to form a transparent resin layer by extruding a molten polyolefin resin.

  In the transparent resin layer, a filler, a matting agent, a foaming agent, a flame retardant, a lubricant, an antistatic agent, an antioxidant, an ultraviolet absorber, a light stabilizer, a radical scavenger, a soft component (for example, as necessary) Various additives such as rubber) may be included.

  The thickness of the transparent resin layer is not particularly limited, but generally may be about 10 to 150 μm.

  The transparent resin layer can be provided with an uneven pattern as necessary. For example, it is possible to give a concavo-convex pattern by known embossing or the like. As a result, a three-dimensional appearance can be given to the cosmetic sheet.

≪Ionizing radiation curable resin layer≫
In the present invention, the ionizing radiation curable resin layer is provided as the outermost surface layer. The layer may be colored as long as it is transparent. Further, it may be translucent as long as the pattern layer is visible. By forming the ionizing radiation curable resin layer, the scratch resistance of the decorative sheet surface can be improved.

  A well-known thing or a commercial item can be used for ionizing radiation curable resin. Specifically, a composition containing at least one of a prepolymer, an oligomer and a monomer having a polymerizable unsaturated bond or an epoxy group in the molecule is used.

  Examples of the prepolymer or oligomer include unsaturated polyesters such as a condensate of unsaturated dicarboxylic acid and polyhydric alcohol. For example, there are methacrylates such as polyester methacrylate, polyether methacrylate, polyol methacrylate, melamine methacrylate, urethane acrylates, polyester acrylate, polyether acrylate, urethane acrylate, polyol acrylate, acrylates such as melamine acrylate, etc. .

  Monomers include styrene monomers such as styrene and α-methylstyrene, acrylic acid such as methyl acrylate, 2-ethylhexyl acrylate, methoxyethyl acrylate, butoxyethyl acrylate, butyl acrylate, and phenyl acrylate. Examples include esters, methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, ethoxymethyl methacrylate, phenyl methacrylate, and lauryl methacrylate.

  As substituted amino alcohol esters of unsaturated acids, acrylic acid-2- (N, N-diethylamino) ethyl, methacrylic acid-2- (N, N-diethylamino) ethyl, acrylic acid-2- (N, N- Dibenzylamino) methyl, acrylic acid-2- (N, N-diethylamino) propyl, and the like.

  In addition, unsaturated carboxylic acid amides such as acrylamide and methacrylamide, ethylene glycol diacrylate, propylene glycol diacrylate, neobenzyl glycol diacrylate, 1,6-hexanediol diacrylate, ethyl carbitol acrylate, diethylene glycol diacrylate, A compound such as triethylene glycol diacrylate, a multifunctional product such as dipropylene glycol diacrylate, ethylene glycol acrylate, diethylene glycol dimethacrylate, or polyethylene glycol diacrylate, and / or having two or more thiol groups in the molecule Polythiol compounds such as trimethylolpropane trithioglycolate, trimethylolpropane trithiopropiolate, There are data pentaerythritol tetra thioglycolic like. Examples of the acrylate monomer having three or more functional groups include trimethylolpropane triacrylate, pentaerythritol hexaacrylate, dipentaerythritol hexamethacrylate, and the like.

  Although the formation method of ionizing radiation curable resin is not limited, For example, it can form by irradiating ionizing radiation to the coating film of the composition (paint) containing ionizing radiation curable resin. The ionizing radiation may be any ionizing radiation curable resin contained in the paint and any energy that can act on the radical photopolymerization initiator / sensitizer as an additive to initiate a radical polymerization reaction. And electromagnetic waves such as γ rays. Among these, the electron beam is most practical from the viewpoint of the curing ability of the coating film and the simplicity of the irradiation device. In the case of electron beam irradiation, for example, the film may be crosslinked and cured by electron beam irradiation under conditions of 175 keV and 5 Mrad (50 kGy).

  The ionizing radiation curable resin layer (that is, the outermost surface of the decorative sheet) is preferably provided with an uneven pattern by embossing or the like.

  Embossing is performed to give a desired texture such as the surface of a wood board to the decorative sheet. For example, after acrylic resin is heated and softened on a heating drum, it is further heated to 160 to 180 ° C. with an infrared radiation heater, pressed and shaped with an embossed plate provided with an uneven pattern of a desired shape, and cooled and fixed. To form. For this, a known single wafer or rotary embossing machine may be used. Examples of the concavo-convex pattern include a wood grain conduit groove, a float pattern (a concavo-convex pattern of a raised annual ring), a hairline, a grain, a satin, and the like, and a desired pattern can be appropriately selected from these.

  In the present invention, the ionizing radiation curable resin layer may contain other components. For example, additives such as a solvent, an ultraviolet absorber, an antioxidant, a dispersant, a light stabilizer, a gloss adjusting agent, an antiblocking agent, and a lubricant can be blended.

  The thickness of the ionizing radiation curable resin layer is not limited, but is usually 0.1 to 50 μm, particularly 1 to 20 μm.

Decorative plate The decorative plate of the present invention is obtained by laminating the decorative sheet of the present invention on an adherend (base material). More specifically, the sheet is laminated on the substrate so that the curable resin layer of the decorative sheet becomes the outermost surface layer.

≪Base material≫
The base material to which the decorative sheet of the present invention is applied is not limited, and the same substrate as a known decorative sheet can be used. For example, wood materials, metals, ceramics, plastics, glass and the like can be mentioned. In particular, the decorative sheet of the present invention can be suitably used for a wood material. Specifically, wood materials include veneer, wood veneer, wood plywood, particle board, medium density fiberboard (MDF) made from various materials such as cedar, firewood, firewood, pine, lawan, teak, and melapie. ) And the like.

≪Lamination on substrate≫
The lamination of the decorative sheet to the base material can be performed in the same manner as the lamination of a known decorative sheet. For example, it is possible to suitably laminate a decorative sheet on a substrate by using an adhesive.

  Examples of usable adhesives include various adhesives such as thermoplastic resin, thermosetting resin, and rubber. As this, a known product or a commercially available product can be used.

  Thermoplastic resin adhesives include polyvinyl acetate resin, polyvinyl alcohol, polyvinyl acetal (polyvinyl formal, polyvinyl butyral, etc.), cyanoacrylate, polyvinyl alkyl ether, polyvinyl chloride, polyamide, polymethyl methacrylate, nitrocellulose, acetic acid Examples include cellulose, thermoplastic epoxy, polystyrene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and the like.

  Thermosetting resin adhesives include urea resin, melamine resin, phenol resin, resorcinol resin, furan resin, epoxy resin, unsaturated polyester resin, polyurethane resin, polyimide, polyamideimide, polybenzimidazole, polybenzothiazole, etc. Illustrated.

  Rubber (elastomer) adhesives include natural rubber, recycled rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, chloroprene rubber, butyl rubber, polysulfide rubber, silicone rubber, polyurethane rubber, stereo rubber (synthetic natural rubber), ethylene propylene rubber And block copolymer rubber (SBS, SIS, SEBS, etc.).

  Since the decorative sheet of the present invention has the primer layer, the weather resistance adhesion and solvent resistance adhesion of the curable resin layer are good. In addition, the primer layer has a good surface condition (no spots, streaks, etc.) and excellent recoatability, and a curable resin layer can be satisfactorily formed even after a lapse of time from the formation of the primer layer.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the examples.

Example 1 (Formation of decorative sheet)
A decorative sheet (layer structure: substrate sheet / picture layer / adhesive layer / transparent resin layer / primer layer / ionizing radiation curable resin layer) was prepared.

  A colored polypropylene resin layer having a thickness of 60 μm was prepared as a base sheet. As a transparent resin layer, a transparent polypropylene resin layer having a thickness of 80 μm was prepared.

  A pattern layer was formed on the base sheet using a solvent-based printing ink containing an acrylic urethane resin.

  Next, an adhesive layer (thickness: 10 μm) was formed using a solvent-based adhesive containing a polyester urethane resin.

  Next, a transparent polypropylene resin layer was laminated.

  Next, a primer layer (thickness: 2 μm) was formed using an aqueous composition described later.

  Next, after film formation using a solvent-based coating agent containing 40 parts of bifunctional urethane acrylate oligomer, 10 parts of hexafunctional urethane acrylate oligomer, 5 parts of silica and 45 parts of ethyl acetate, electron beam irradiation (175 keV and 5 Mrad (50 kGy) As a result, an ionizing radiation curable resin layer (thickness 5 μm) was formed.

  A decorative sheet was prepared through the above process.

≪Aqueous composition≫
The aqueous composition for forming the primer layer was mainly composed of a mixture of acrylic-urethane copolymer, water, isopropyl alcohol (IPA), silica and ultraviolet absorber (UVA), and isocyanate as a curing agent.

  As the acrylic-urethane copolymer, those obtained by reaction of acrylic polyol, polyester polyol, diisocyanate (isophorone diisocyanate (IPDI)) and hydroxycarboxylic acid (2,2bis (hydroxymethyl) propionic acid) were used.

  The acrylic-urethane copolymer was neutralized with triisopropanolamine to make it aqueous.

  The polyester polyol used was adipic acid polyester polyol / isophthalic acid polyester polyol = 50/50 (parts by weight).

  The copolymerization ratio of acrylic polyol and polyester polyol was 50:50 (weight ratio).

  The amount of diisocyanate was adjusted so that the molar ratio of acrylic polyol, polyester polyol and hydroxycarboxylic acid OH to NCO was 1: 1.

  The amount of hydroxycarboxylic acid was adjusted so that the acid value before neutralization of the acrylic-urethane copolymer was 42 mgKOH / g.

  As isocyanate (curing agent), polyisocyanate of isocyanurate-modified polyisocyanate (HDI nurate) / allophanate group-containing polyisocyanate (allophanate) = 50/50 (weight ratio) was used.

  The ratio of water / IPA was set to be water / IPA = 7/3.

  Two types of aqueous compositions were prepared, one immediately after the addition of the curing agent to the main agent and the one three hours after the addition of the curing agent to the main agent. This is to evaluate the pot life of the aqueous composition. The amount of curing agent added was 50 parts by weight with respect to 100 parts by weight of the acrylic-urethane copolymer.

  The average particle size of the copolymer in the aqueous composition was 60.4 nm.

Reference example 1
A coating film formed in the same manner as in Example 1 was used as a primer except that the composition of the curing agent was a ratio of HDI-based nurate / allophanate = 70/30 (weight ratio).

Reference example 2
A coating film formed in the same manner as in Example 1 was used as a primer, except that the composition of the curing agent was HDI nurate / allophanate = 30/70 (weight ratio).

Comparative Example 1
As the acrylic-urethane copolymer, a solvent-based acrylic-urethane copolymer having a copolymerization ratio of acrylic polyol and polyester polyol of 50:50 (weight ratio) is used, and an HDI curing agent “FG700” ( A coating film formed in the same manner as in Example 1 was used as a primer except that The Inktec Co., Ltd. was used.

Reference example 3
As a water-based acrylic-urethane copolymer, a coating film formed in the same manner as in Example 1 is used as a primer, except that an acrylic polyol / polyester polyol copolymer ratio is 70:30 (weight ratio). did.

Reference example 4
As a water-based acrylic-urethane copolymer, a coating film formed in the same manner as in Example 1 was used as a primer, except that a copolymer having an acrylic polyol and polyester polyol ratio of 30:70 (weight ratio) was used. did.

Reference Example 5
An aqueous acrylic-urethane copolymer having an acid value of 42 mgKOH / g was prepared in the same manner as in Example 1, and then an aqueous composition was prepared in the same manner as in Example 1. The average particle size of the copolymer in the aqueous composition was 60.4 nm. In addition, three types of aqueous compositions are prepared, one immediately after adding a curing agent to the main agent, one after 3 hours after adding the curing agent to the main agent, and one after 5 hours after adding the curing agent to the main agent. did.

Reference Example 6
An aqueous acrylic-urethane copolymer was prepared in the same manner as in Example 1 except that the acid value of the aqueous acrylic-urethane copolymer was set to 15 mgKOH / g by adjusting the amount of hydroxycarboxylic acid. Next, an aqueous composition was prepared in the same manner as in Example 1. The average particle size of the copolymer in the aqueous composition was 345.6 nm. In addition, three types of aqueous compositions are prepared, one immediately after adding a curing agent to the main agent, one after 3 hours after adding the curing agent to the main agent, and one after 5 hours after adding the curing agent to the main agent. did.

Reference Example 7
An aqueous acrylic-urethane copolymer was prepared in the same manner as in Example 1 except that the acid value of the aqueous acrylic-urethane copolymer was set to 19 mgKOH / g by adjusting the amount of hydroxycarboxylic acid. Next, an aqueous composition was prepared in the same manner as in Example 1. The average particle size of the copolymer in the aqueous composition was 88.1 nm. In addition, three types of aqueous compositions are prepared, one immediately after adding a curing agent to the main agent, one after 3 hours after adding the curing agent to the main agent, and one after 5 hours after adding the curing agent to the main agent. did.

Test example 1
The surface state, weather resistance and solvent resistance of the ionizing radiation curable resin layers formed in Examples, Reference Examples 1 to 4 and Comparative Examples were evaluated. Further, the recoatability of the primer layer was evaluated.

  Each evaluation method (test method) was as follows.

≪Test method≫
(1) Surface condition: The presence or absence of groups and streaks on the surface of the ionizing radiation curable resin layer was visually confirmed. The surface state was evaluated as “◯” when there were no spots or streaks, and “×” when there were spots or streaks.
(2) Weather resistance: After the cosmetic sheet was exposed for 192 hours using an i-super UV tester (Iwasaki Electric Co., Ltd.), the coating film (ionizing radiation curable resin layer) was cut with a cutter knife at intervals of 2 mm, and cello tape (registered) (Trademark), a peeling test of the coating film was conducted. The exposure conditions are: temperature 63 ° C., humidity 50% RH, irradiation intensity 60 mw / m ² . The exposure was performed for 8 cycles, with 20 hours of irradiation and 4 hours of condensation as one cycle. The weather resistance was evaluated as ○ when there was no peeling and × when there was peeling between the coating layer and the primer layer.
(3) Solvent resistance: The surface of the ionizing radiation curable resin layer was rubbed 50 times (500 g load). After rubbing, by visual observation, those having no change in appearance were evaluated as ◯, and those whose appearance was whitened were evaluated as ×.
(4) Recoating property: After coating the primer aqueous composition, after standing at 60 ° C. for 48 hours, an ionizing radiation curable resin layer was formed and a weather resistance adhesion test was conducted. After the weather resistance test, a peel test was repeatedly performed 5 times with cello tape (registered trademark). No peeling was marked with ◯, and peeling between the primer layer and the ionizing radiation curable resin layer was marked with x.
(5) Pot life: A primer layer was formed with two types of an aqueous composition immediately after the addition of isocyanate as a curing agent and an aqueous composition three hours after the addition, and the physical properties were compared.

  The test results are shown in Table 1 below.

  As is clear from the results in Table 1, the use of an aqueous primer improves the solvent resistance and recoatability compared to the solvent system. Moreover, it turns out that the balance of a surface state and a pot life becomes good by making an isocyanate hardening | curing agent into HDI type | system | group nurate / allophanate = 50/50 (weight ratio). Furthermore, it can be seen that the acrylic-urethane copolymer has a good balance between weather resistance and recoatability when the copolymerization ratio of acrylic polyol and polyester polyol is 50:50 (weight ratio).

Test example 2
Immediately after applying the aqueous compositions prepared in Reference Examples 5 to 7 (all three) to an aluminum plate using a bar coater # 6 (application amount: 1.7 g / m ² ), a test solution (water / IPA = 7 / 3) was immersed in an aluminum plate for 3 minutes.

  After 3 minutes, a film in which the coating film of the aluminum plate was 100% dissolved (dissolution rate 100%) was evaluated as ◯. Moreover, 70% ≦ dissolution rate <100% was evaluated as “◯ -Δ”. Also, those having a dissolution rate of <70% were evaluated as Δ.

  The evaluation results are shown in Table 2 below.

From the results of Table 2, it can be seen that the aqueous composition of Reference Example 5 having an acid value of 20 mgKOH / g or more exhibits good re-solubility regardless of the curing agent addition time. It can be seen that when the acid value is less than 20 mgKOH / g, the average particle size of the copolymer decreases as the acid value decreases, and at the same time the re-solubility decreases.

Claims (10)

A decorative sheet having a curable resin layer on the outermost surface,
The curable resin layer is laminated on a primer layer made of an aqueous composition containing an acrylic-urethane copolymer and isocyanate ,
The acrylic-urethane copolymer is obtained by reacting at least acrylic polyol, polyester polyol, hydroxycarboxylic acid and diisocyanate,
The copolymerization ratio of the acrylic polyol and the polyester polyol is 40:60 to 60:40 in order by weight.
Makeup sheet . The decorative sheet according to claim 1, wherein the acrylic-urethane copolymer has an acid value of 20 mgKOH / g or more. The decorative sheet according to claim 1 or 2, wherein the isocyanate is a self-emulsifying isocyanate. The decorative sheet according to claim 3, wherein the self-emulsifying isocyanate is a mixture of an isocyanurate-modified polyisocyanate and an allophanate group-containing polyisocyanate. The decorative sheet according to claim 4, wherein the weight ratio of the isocyanurate-modified polyisocyanate and the allophanate group-containing polyisocyanate is 40:60 to 60:40 in order. Polyester polyols, turn 50 and adipate-based polyester polyol and a phthalate polyester polyol: 50-70: containing 30 weight ratio, the decorative sheet according to claim 1. The water-based composition is a decorative sheet according to any one of claims 1 to 6 , comprising 20 to 60 parts by weight of an isocyanate with respect to 100 parts by weight of an acrylic-urethane copolymer. The decorative sheet according to any one of claims 1 to 7 , wherein the curable resin layer is an ionizing radiation curable resin layer. A decorative board formed by laminating the decorative sheet according to any one of claims 1 to 8 and an adherend. A primer layer for laminating the curable resin layer, an acrylic - Ri Do from an aqueous composition containing the urethane copolymer and an isocyanate,
The acrylic-urethane copolymer is obtained by reacting at least acrylic polyol, polyester polyol, hydroxycarboxylic acid and diisocyanate,
The copolymerization ratio of the acrylic polyol and the polyester polyol is 40:60 to 60:40 in order by weight.
Primer layer .