Active energy ray-curable type coating agent, and laminate manufacturing method

Abstract

To provide an active energy ray-curable type coating agent having both scratch resistance and post-embossment workability, and a laminate manufacturing method.SOLUTION: There are provided an active energy ray-curable coating agent satisfying (1), (2) and (3), and a laminate manufacturing method. (1) An active energy ray-curable compound contains a polyfunctional urethane (meth)acrylate oligomer (A) and a polyfunctional (meth)acrylate monomer (B). (2) Storage elastic modulus measured at 130°C of a cured product obtained by curing the total amount of the active energy ray-curable compound is 1.0×107 to 5.0×108 Pa, and breaking strain thereof is 1.5% to 5%. (3) As inorganic fine particles, 1 to 20 mass% of silica (C), and 1 to 15 mass% of inorganic fine particles (D) other than the silica are contained.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an active energy ray-curable coating agent and a method for producing a laminate using the coating agent. [Background technology]

[0002] Decorative sheets printed with wood grain patterns, etc., are often used on the surfaces of architectural interior materials and fittings. For the purpose of protection and beautification, the surface layer of these decorative sheets is coated with a coating agent that is curable by active energy rays, such as ultraviolet rays and electron beams.

[0003] Known examples of active energy ray curable coating agents for decorative sheets include decorative sheets for building materials, in which the thickness of the curable resin layer is 10 to 50 μm and which use urethane acrylate and a polyfunctional monomer (see, for example, Patent Document 1); ultraviolet-curable paint compositions for coating plastic substrates, which use a tack-free trifunctional or higher urethane acrylate resin and a specific photopolymerization initiator (see, for example, Patent Document 2); photocurable topcoat resin compositions using a tetrafunctional or higher urethane acrylate, a trifunctional monomer, inorganic fine particles, and a photopolymerization initiator (see, for example, Patent Document 3); ultraviolet-curable coating agent compositions that do not use urethane acrylate, trifunctional or higher acrylate, a specific photopolymerization initiator, or a solvent (see, for example, Patent Document 4); low-gloss coating agents that contain a specific acrylic acrylate and silica (see, for example, Patent Document 5); and decorative sheets for building materials that use a specific bifunctional urethane acrylate and a 3- to 15-functional urethane acrylate in a specific ratio (see, for example, Patent Document 6).

[0004] These coating agents have traditionally been required to have a variety of properties, including "abrasion and scratch resistance" to prevent damage caused by rubbing or scratching, "chemical resistance" to prevent deterioration due to chemical adhesion, "pollution resistance" to prevent stains from various pollutants, and "weather resistance" to prevent deterioration due to ultraviolet rays, etc. In recent years, there has also been a demand for "post-embossing processability" that allows the application of unevenness after curing to improve design, and there is a demand for coating agents that combine all of these properties. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 4723704 [Patent Document 2] Patent No. 6941747 [Patent Document 3] Patent Publication No. 2022-55408 [Patent Document 4] Patent No. 6658184 [Patent Document 5] Patent No. 6637950 [Patent Document 6] Patent No. 5545331 Summary of the Invention [Problem to be solved by the invention]

[0006] The problem to be solved by the present invention is to provide an active energy ray-curable coating agent that combines abrasion resistance, scratch resistance, chemical resistance, contamination resistance, weather resistance, and post-embossing processability, and a method for producing a laminate using the active energy ray-curable coating agent. [Means for solving the problem]

[0007] That is, the present invention provides an active energy ray-curable coating agent that contains an active energy ray-curable compound and inorganic fine particles and satisfies (1), (2), and (3). (1) The active energy ray-curable compound contains a polyfunctional urethane (meth)acrylate oligomer (A) and a polyfunctional (meth)acrylate monomer (B). (2) The storage modulus of the cured product obtained by curing the entire amount of the active energy ray-curable compound is 1.0×10 7 ~5.0×10 8 Pa and the breaking strain is 1.5% to 5%. (3) As inorganic fine particles, silica (C) is contained in an amount of 1 to 20 mass % based on the total amount of the active energy ray-curable compound, and inorganic fine particles other than silica (D) are contained in an amount of 1 to 15 mass % based on the total amount of the active energy ray-curable compound.

[0008] The present invention also provides a method for producing a laminate, comprising the steps of: (I) forming a coating film of an active energy ray-curable coating agent on a substrate; and (II) irradiating the coating film with active energy rays, in this order; wherein the active energy ray-curable coating agent is the active energy ray-curable coating agent according to any one of claims 1 to 6. Effect of the Invention

[0009] According to the present invention, it is possible to provide an active energy ray-curable coating agent having abrasion resistance, scratch resistance, chemical resistance, contamination resistance, weather resistance, and post-embossing processability. Also, according to the present invention, it is possible to provide a laminate useful as a decorative sheet having a cured coating film of an active energy ray-curable coating agent having abrasion resistance, scratch resistance, chemical resistance, contamination resistance, weather resistance, and post-embossing processability. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] (Definition of words) In the present invention, "(meth)acrylate" refers to either or both of acrylate and methacrylate. Also, "(meth)acryloyl group" refers to either or both of acryloyl group and methacryloyl group. Also, "a compound having a (meth)acryloyl group" may be called a (meth)acrylate.

[0011] (Active energy ray curable compound) The active energy ray-curable compound used in the present invention refers to a compound having a (meth)acryloyl group that can be cured by active energy rays (hereinafter may be simply referred to as "active energy ray-curable"), and contains a polyfunctional urethane (meth)acrylate oligomer (A) and a polyfunctional (meth)acrylate monomer (B).

[0012] (Multifunctional urethane (meth)acrylate oligomer (A)) The urethane (meth)acrylate oligomer used in the present invention is a resin obtained by condensing an isocyanate group-containing monomer and a hydroxyl group-containing monomer, and the terminals of the urethane resin are modified with an acryloyl group or a methacryloyl group. Among them, a bifunctional or higher polyfunctional urethane (meth)acrylate oligomer in which both terminals are modified with an acryloyl group or a methacryloyl group is essential. This makes it possible to obtain an active energy ray curable coating agent having excellent durability and toughness. In the present invention, any known polyfunctional urethane (meth)acrylate oligomer can be used without any particular limitation. In addition, a mixture of multiple types of polyfunctional urethane (meth)acrylate oligomers may be used.

[0013] The amount of the polyfunctional urethane (meth)acrylate oligomer (A) added is preferably 35 to 80% by mass, more preferably 40 to 60% by mass, based on the total amount of the active energy ray curable compound. If it is 35% by mass or more, the extensibility for imparting post-embossing processability is improved. If it is 80% by mass or less, an extreme increase in viscosity can be suppressed, making it easy to form a coating film.

[0014] (Polyfunctional (meth)acrylate monomer (B)) The polyfunctional (meth)acrylate monomer (B) used in the present invention includes a compound having two or more (meth)acryloyl groups. Examples of bifunctional (meth)acrylates include 1,4-butanediol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 2-methyl-1,8-octanediol di(meth)acrylate, 2-butyl-2-ethyl-1,3-propanediol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, dipropionyl ... Examples of the di(meth)acrylate include dihydric alcohol di(meth)acrylates such as ethylene glycol di(meth)acrylate and tripropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, di(meth)acrylate of tris(2-hydroxyethyl)isocyanurate, di(meth)acrylates of diols obtained by adding 4 or more moles of ethylene oxide or propylene oxide to 1 mole of neopentyl glycol, and di(meth)acrylates of diols obtained by adding 2 moles of ethylene oxide or propylene oxide to 1 mole of bisphenol A.

[0015] Examples of the trifunctional or higher (meth)acrylate include poly(meth)acrylates of trivalent or higher polyhydric alcohols such as trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, and dipentaerythritol poly(meth)acrylate; poly(meth)acrylates of polyoxyalkylene polyols such as triol tri(meth)acrylates obtained by adding 3 moles or more of ethylene oxide or propylene oxide to 1 mole of glycerin, triol di- or tri(meth)acrylates obtained by adding 3 moles or more of ethylene oxide or propylene oxide to 1 mole of trimethylolpropane, and di(meth)acrylates of diols obtained by adding 4 moles or more of ethylene oxide or propylene oxide to 1 mole of bisphenol A.

[0016] Furthermore, a mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate (sometimes abbreviated as DPHA), which are bifunctional or higher (meth)acrylates, ditrimethylolpropane tetraacrylate (sometimes abbreviated as DTMPTA), trimethylolpropane ethylene oxide adduct tri(meth)acrylate, which is a triol tri(meth)acrylate obtained by adding 3 moles or more of ethylene oxide to 1 mole of trimethylolpropane, etc. may be used. A representative example of the trimethylolpropane ethylene oxide adduct tri(meth)acrylate is trimethylolpropane ethylene oxide (hereinafter, ethylene oxide may be referred to as "EO") modified (n≒3) triacrylate.

[0017] The amount of the polyfunctional (meth)acrylate monomer (B) added is preferably 20 to 65% by mass, more preferably 40 to 60% by mass, of the total amount of the active energy ray curable compound. If the amount of the polyfunctional (meth)acrylate monomer (B) is 20% by mass or more, a coating film having excellent chemical resistance can be obtained, and if it is 65% by mass or less, the extensibility for imparting post-embossing processability is improved.

[0018] It is also preferable to use a polyfunctional (meth)acrylate monomer having a glycerin skeleton as the polyfunctional (meth)acrylate monomer (B). The polyfunctional (meth)acrylate monomer having a glycerin skeleton may be a part of the polyfunctional (meth)acrylate monomer (B), or the entire polyfunctional (meth)acrylate monomer may be a polyfunctional (meth)acrylate monomer having a glycerin skeleton. Specifically, the (meth)acrylate having a glycerin skeleton is preferably 40 to 100% by mass based on the total amount of the polyfunctional (meth)acrylate monomer (B). The (meth)acrylate having a glycerin skeleton is preferably a compound having 2 to 4 (meth)acryloyl groups, and more preferably a compound having 3 or 4 (meth)acryloyl groups.

[0019] Specific examples include glycerin diacrylate, glycerin dimethacrylate, ethylene oxide-modified glycerin diacrylate, ethylene oxide-modified glycerin dimethacrylate, propylene oxide-modified glycerin diacrylate, propylene oxide-modified glycerin dimethacrylate, glycerin triacrylate, glycerin trimethacrylate, ethylene oxide-modified glycerin triacrylate, ethylene oxide-modified glycerin trimethacrylate, propylene oxide-modified glycerin triacrylate, propylene oxide-modified glycerin trimethacrylate, diglycerin acrylate, ethylene oxide-modified diglycerin acrylate, and propylene oxide-modified diglycerin acrylate. As commercially available products, glycerin diacrylate "Aronix M-920 (ratio of plant raw materials: 45%)" and glycerin triacrylate "Aronix M-930 (ratio of plant raw materials: 37%)" manufactured by Toa Gosei Co., Ltd., which have been certified by the Japan Organic Resources Association as having a biomass content (content of biomass raw materials contained in the product (dry weight ratio)) of 35%, are preferred. The ratio of the plant raw materials is calculated by dividing the molecular weight of the plant-derived raw material skeleton by the total molecular weight x 100, based on the description in Toa Gosei Group Research Annual Report 26TREND2020, No. 23. In addition, an example of the ethylene oxide-modified diglycerin acrylate is "Aronix M-460 (ratio of plant raw materials: 25%)" manufactured by Toa Gosei Co., Ltd. Among these, the addition of glycerin triacrylate "Aronix M-930" and ethylene oxide modified diglycerin acrylate "Aronix M-460" is preferred as it tends to maintain the weather resistance of the active energy ray curable coating agent. In addition, these materials contain a high proportion of plant raw materials and are also preferred as carbon-neutral materials (biomass) that reduce the emission of carbon dioxide into the environment.

[0020] Furthermore, in order to adjust the viscosity of the active energy ray-curable coating agent of the present invention, a monofunctional monomer which is a (meth)acryloyl group-containing compound may be used. Examples of the monofunctional monomer include ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, hexadecyl (meth)acrylate, octadecyl (meth)acrylate, isoamyl (meth)acrylate, isodecyl (meth)acrylate, isostearyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, methoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, phenoxyethyl (meth)acrylate, and phenoxydiethylene glycol (meth). ) acrylate, nonylphenoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, glycidyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, diethylaminoethyl (meth)acrylate, nonylphenoxyethyl tetrahydrofurfuryl (meth)acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, and the like.

[0021] Furthermore, if necessary, a polymerizable oligomer may be used. Examples of the polymerizable oligomer include amine-modified polyether acrylate, amine-modified epoxy acrylate, amine-modified aliphatic acrylate, amine-modified polyester acrylate, amine-modified acrylate such as amino(meth)acrylate, polyester(meth)acrylate, polyether(meth)acrylate, polyolefin(meth)acrylate, polystyrene(meth)acrylate, and epoxy(meth)acrylate. Among these polymerizable oligomers, epoxy(meth)acrylate is preferred.

[0022] When an active energy ray-curable compound other than the polyfunctional urethane (meth)acrylate oligomer (A) and the polyfunctional (meth)acrylate monomer (B) is used in combination, it is preferable to use it in an amount of 15 mass% or less based on the total amount of the polyfunctional urethane (meth)acrylate oligomer (A) and / or the polyfunctional (meth)acrylate monomer (B), within a range in which the effect of the compound is not impaired.

[0023] (storage modulus, breaking strain) In the present invention, the storage modulus of the cured product obtained by curing the entire amount of the active energy ray-curable compound measured at 130° C. is 1.0×10 7 ~5.0×10 8 It is characterized by a strength of 1.5 Pa and a breaking strain of 1.5% to 5%.

[0024] In the present invention, the cured product obtained by curing the entire amount of the active energy ray curable compound is specifically a composition obtained by adding 2 parts by mass of 1-hydroxycyclohexyl phenyl ketone (Omnirad184, manufactured by IGM Resins BV) as a photopolymerization initiator to 100 parts by mass of the total amount of the active energy ray curable compound contained in the active energy ray curable coating agent of the present invention, pouring the composition into a silicone mold having a thickness of 0.25 mm, a width of 5 mm, and a length of 50 mm, and irradiating the composition with ultraviolet light (240 mJ / cm 2 ) is a hardened material. The total amount of the active energy ray curable compounds contained in the active energy ray curable coating agent of the present invention is 100 parts by mass, calculated backwards from the amount of each active energy ray curable compound contained in the coating agent. For example, if the active energy ray curable compounds contained in the coating agent are a mixture of 30 g of compound a, 15 g of compound b, and 5 g of compound c (total amount is 50 g), the amount of photopolymerization initiator is 1 g.

[0025] In the present invention, the storage modulus (E') is a value measured in the following manner in accordance with JIS K 7244-4. Specifically, the cured product in the form of a strip was removed from the silicone mold and subjected to temperature dependence measurement at a frequency of 1 Hz and a heating rate of 5°C / min using a dynamic viscoelasticity measuring device RSA-G2 (manufactured by TA Instruments), and the storage modulus (E') at 130°C was recorded.

[0026] In the present invention, the breaking strain (%) is a value measured as follows. Specifically, the cured product in the form of a strip was removed from the silicone mold and strain-dependent measurements were performed using a dynamic viscoelasticity measuring device RSA-G2 (manufactured by TA Instruments) at a temperature of 130°C, a frequency of 1Hz, and a strain of 0.1 to 6%, and the strain point at which the storage modulus in the stable region suddenly drops due to cracks or breakage was taken as the breaking strain (%). Although a known statistical abnormal value detection method can be used to determine the point at which a sudden drop occurs, it is usually sufficient to identify the strain point at which the measured sample breaks by visual observation. The measurements were performed three times, and the arithmetic average value was used.

[0027] In the present invention, the above-mentioned "active energy ray-curable compound contains a polyfunctional urethane (meth)acrylate oligomer (A) and a polyfunctional (meth)acrylate monomer (B)" and "the storage modulus of the cured product obtained by curing the entire amount of the active energy ray-curable compound measured at 130° C. is 1.0×10 7 ~5.0×10 8 By satisfying the conditions "tensile strength of the resin is 1.5 Pa and the breaking strain is 1.5% to 5%", it is possible to obtain a coating film that is particularly suitable for post-embossing processability and scratch resistance.

[0028] The storage modulus is preferably 5.0×10 7 ~5.0×10 8 The range of Pa is preferably 8.0×10 7 ~4.0×10 8 The breaking strain is preferably in the range of 1.7% to 4.0%, more preferably in the range of 2.0 to 4.0%.

[0029] (Inorganic fine particles) The active energy ray-curable coating agent of the present invention must contain, as inorganic fine particles, silica (C) and inorganic fine particles other than silica (D).

[0030] (Silica (C)) The silica (C) used in the present invention is not particularly limited, and any known silica can be used. Specifically, amorphous silica is more preferable. Examples of the amorphous silica include diatomaceous earth and activated clay. Among the amorphous silica, dry silica, wet silica, silica gel, etc. can be used as synthetic amorphous silica. Among them, wet silica produced by neutralizing and decomposing an aqueous solution of sodium silicate with an acid or an alkali metal salt is preferable. The wet silica can also be surface-treated. The method of surface-treating the silica particles is not particularly limited and may be any known method. Examples of the wet silica include those surface-treated with wax or a silane coupling agent. The wet silica may be used by mixing a plurality of the surface-treated and non-surface-treated wet silicas.

[0031] The average particle size of the silica (C) is preferably 0.1 to 20 μm, more preferably 1.5 to 15 μm. If the particle size is too small, the matte finish / scratch resistance may not be achieved, whereas if the particle size is too large, the appearance of the coating film may be adversely affected. The content of the silica (C) is preferably 1 to 20% by mass based on the total amount of the active energy ray-curable compound. By setting the content within this range, it is possible to maintain a viscosity that allows application as a coating agent, as well as abrasion resistance and scratch resistance. Among these, 5 to 15% by mass is more preferable.

[0032] (Inorganic particles other than silica (D)) Specific examples of the inorganic fine particles (D) other than silica used in the present invention include silicone, titanium oxide, zinc oxide, aluminum oxide, calcium carbonate, barium sulfate, glass, aluminosilicates, etc. Among these, aluminosilicates are preferred in terms of improving scratch resistance.

[0033] The inorganic fine particles (D) preferably have an average particle size of 0.1 to 15 μm, more preferably 2 to 10 μm. If the particle size is too small, the matte finish / scratch resistance may not be achieved, whereas if the particle size is too large, the appearance of the coating film may be adversely affected. The content of the inorganic fine particles (D) is preferably 1 to 15% by mass of the total amount of the active energy ray curable compound. By setting it in this range, it is possible to maintain a viscosity that allows application as a coating agent, as well as abrasion resistance and scratch resistance. Among them, 4 to 10% by mass is more preferable, and 5 to 9% by mass is most preferable.

[0034] (Cellulose-based resin) The active energy ray curable coating agent of the present invention preferably contains a cellulose-based resin having a number average molecular weight of 10,000 to 80,000. The content may be 1 to 10 mass% based on the total mass of the active energy ray curable coating agent. By containing the cellulose-based resin, chemical resistance in particular tends to be improved.

[0035] Examples of the cellulose resin include cellulose acetate propionate, cellulose acetate butyrate and other cellulose ester resins, nitrocellulose (also called nitrocellulose), hydroxyalkylcellulose, and carboxyalkylcellulose. The cellulose ester resin preferably has an alkyl group, and examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, and a hexyl group, and the alkyl group may further have a substituent. Of the above, the cellulose-based resin is preferably cellulose acetate propionate, cellulose acetate butyrate, or nitrocellulose, and more preferably cellulose acetate propionate or cellulose acetate butyrate. The molecular weight is preferably 10,000 to 80,000 in number average molecular weight, more preferably 20,000 to 40,000. By making the number average molecular weight 10,000 or more, it is possible to obtain an effect of improving chemical resistance, and by making it 80,000 or less, it is possible to maintain a viscosity that allows application as a coating agent. In addition, it is preferable that the glass transition temperature is 120°C to 180°C. The combined use of the polyfunctional urethane (meth)acrylate oligomer and the polyfunctional (meth)acrylate monomer is expected to improve chemical resistance. Also, the combined use of the polyfunctional urethane (meth)acrylate oligomer and the acrylate having a glycerin skeleton tends to improve weather resistance, abrasion resistance, and scratch resistance.

[0036] The cellulose-based resin is preferably contained in an amount of 1 to 10% by mass based on the total mass of the active energy ray-curable coating agent, and can also be used as a biomass raw material.

[0037] (Photopolymerization initiator) The active energy ray curable coating agent of the present invention usually uses a photopolymerization initiator, but this is not limited to the case where a curing method that does not require a photopolymerization initiator, such as an electron beam, is selected. As the photopolymerization initiator to be used, a known one may be used.

[0038] Among them, radical polymerization type photopolymerization initiators are preferred, and α-hydroxyalkyl ketone-based photopolymerization initiators are preferred, which do not color the solution when the active energy ray curable compound is dissolved and do not yellow over time. Examples of α-hydroxyalkyl ketone-based photopolymerization initiators include 1-phenyl-2-hydroxy-2-methylpropan-1-one, 1-(4-i-propylphenyl)-2-hydroxy-2-methylpropan-1-one, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, and 1-hydroxycyclohexyl phenyl ketone. Furthermore, phenylglyoxolate-based photopolymerization initiators are also preferred. Examples of phenylglyoxolate-based photopolymerization initiators include methylbenzoyl formate. Among them, 1-hydroxycyclohexyl phenyl ketone is preferred.

[0039] As other radical polymerization type photopolymerization initiators, monoacylphosphine oxide-based photopolymerization initiators having an absorption wavelength in the long wavelength region of ultraviolet light may be used in appropriate combination. Examples of the monoacylphosphine oxide photopolymerization initiator include monoacylphosphine oxides such as 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,6-dimethoxybenzoyl-diphenylphosphine oxide, 2,6-dichlorobenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoyl-phenylphosphine acid methyl ester, 2-methylbenzoyl-diphenylphosphine oxide, and pivaloylphenylphosphine acid isopropyl ester, excluding bisacylphosphine oxides that become colored when dissolved in an active energy ray-curable compound. Among these, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide is particularly preferred in that it has a UV absorption wavelength that matches the emission wavelength region of UV-LEDs having an emission wavelength of 385 nm or 395 nm, thereby obtaining suitable curability and causing less yellowing of the cured film.

[0040] When the photopolymerization initiators are used, they may be used alone or in combination of two or more. The total amount of the photopolymerization initiators is preferably in the range of 0.01 to 15.0% by mass of the total mass of the active energy ray curable coating agent. If it is 0.01% by mass or more, good curability can be obtained. Also, if it is 15.0% by mass or less, the fluidity of the coating agent can be maintained for a long time, and good processability and workability can be ensured.

[0041] Furthermore, the curing speed can be increased by adding a tertiary amine compound selected from aliphatic amine derivatives and / or benzoic acid amine derivatives as a sensitizer. Tertiary amine compounds are known to increase reactivity and prevent reaction inhibition by oxygen. Suitable tertiary amine compounds include free alkylamines such as triethylamine, methyldiethanolamine, and triethanolamine, aromatic amines such as 2-ethylhexyl-4-dimethylaminobenzoate and ethyl-4-dimethylaminobenzoate, and active energy ray polymerizable compounds such as polymeric unsaturated amines (e.g., (meth)acrylated amines), which are considered to be preferred due to their low odor, low volatility, and ability to be incorporated into the polymer matrix by curing, thereby suppressing yellowing.

[0042] The tertiary amine compound can be used in an amount of preferably 0.1 to 10 mass %, more preferably 0.3 to 3 mass %, based on the total mass of the active energy ray-curable coating agent.

[0043] (Organic solvent) From the viewpoint of coatability, the active energy ray-curable coating agent of the present invention may be adjusted to a coatable viscosity by using an organic solvent or the like in the coating film production method of the present invention described below. The viscosity is preferably adjusted to 30 to 10,000 mPa·s, and more preferably 30 to 5,000 mPa·s. The organic solvent used in this case may be any solvent that dissolves the active energy ray-curable coating agent used. Examples of the solvent include aromatic hydrocarbons such as toluene and xylene; aliphatic or alicyclic hydrocarbons such as n-hexane, cyclohexane, methylcyclohexane, and ethylcyclohexane; esters such as ethyl acetate, butyl acetate, and propyl acetate; alcohols such as methanol, ethanol, isopropyl alcohol, and n-butanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; alkylene glycol monoalkyl ethers such as ethylene glycol monoethyl ether and propylene glycol monomethyl ether; and ether esters such as propylene glycol monomethyl ether acetate.

[0044] (Other resins) Furthermore, known binder resins can be used in combination as necessary. Examples of such binder resins include vinyl chloride resins such as vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl isobutyl ether copolymer resin, rosin resin, polyurethane resin, polyamide resin, chlorinated polypropylene resin, ethylene-vinyl acetate copolymer resin, vinyl acetate resin, and polyvinyl chloride resin, polyester resin, alkyd resin, ketone resin, cyclized rubber, chlorinated rubber, butyral, and petroleum resin.

[0045] (Additives) In addition, the active energy ray-curable coating agent of the present invention may contain, as necessary, a polymerization inhibitor, a leveling agent, a thixotropy imparting agent, a wax, a drying agent, a thickening agent, an anti-sagging agent, a plasticizer, a dispersant, an anti-settling agent, an antifoaming agent, an ultraviolet absorbing agent, a light stabilizer, and the like. In particular, in order to improve weather resistance, ultraviolet absorbents and light stabilizers are useful as weather resistance additives. Hydroxyphenyltriazine-based ultraviolet absorbents and hindered amine-based light stabilizers are preferred. The amount of the ultraviolet absorber added is preferably 0.1 to 5 mass % of the total amount of the active energy ray-curable coating agent of the present invention, and more preferably 0.5 to 3 mass %. The amount of the light stabilizer added is preferably 0.1 to 5 mass % of the total amount of the active energy ray-curable coating agent of the present invention, and more preferably 1 to 4 mass %.

[0046] (Method of manufacturing active energy ray curable coating agent) The active energy ray-curable coating agent of the present invention can be produced by mixing, kneading, and dispersing a polyfunctional urethane (meth)acrylate oligomer, a polyfunctional (meth)acrylate monomer, silica, inorganic fine particles other than silica, a cellulose-based resin, a photopolymerization initiator, a weather resistance additive, an organic solvent, and various other additives. The active energy ray-curable coating agent of the present invention can be prepared by appropriately adjusting the size of the grinding media of the dispersing machine, the packing rate of the grinding media, the dispersion treatment time, etc. As the dispersing machine, a commonly used one, for example, a roller mill, a ball mill, a pebble mill, an attritor, a sand mill, etc. can be used. When the coating agent contains air bubbles or coarse particles, these deteriorate the quality of the coating product, and therefore it is preferable to remove them by filtration, etc. As the filter, a conventionally known filter can be used.

[0047] (Method of forming coating film) The active energy ray curable coating agent of the present invention can form a coating film by a known coating / printing method. Specific examples of the coating method include roll coaters, gravure coaters, gravure offset coaters, flexo coaters, air doctor coaters, blade coaters, air knife coaters, squeeze coaters, impregnation coaters, transfer roll coaters, kiss coaters, curtain coaters, cast coaters, spray coaters, die coaters, offset printers, screen printers, etc.

[0048] When the coating agent used contains an organic solvent, the coating film formed by the above-mentioned formation method can be cured by drying the organic solvent in a drying oven or the like and then curing the coating film with active energy rays to obtain a cured coating film.

[0049] (base material) The substrate used in the present invention is not particularly limited. For example, in the case of a decorative sheet for building materials, a general-purpose substrate sheet used for decorative sheets can be used as the substrate. There are no particular limitations on the base sheet, and a typical decorative sheet such as a sheet (film) made of a general-purpose thermoplastic resin or paper can be used. Examples of sheets (films) formed from thermoplastic resins include polyolefin resins such as polyethylene, ethylene-α-olefin copolymers, polypropylene, polymethylpentene, polybutene, ethylene-propylene copolymers, propylene-butene copolymers, ethylene-vinyl acetate copolymers, saponified ethylene-vinyl acetate copolymers, ethylene-(meth)acrylic acid copolymers, and ethylene-(meth)acrylic acid ester copolymers, polyvinyl chloride, polyethylene terephthalate (PET), polybutylene terephthalate, polyamide, polycarbonate, polyethylene naphthalate, ionomers, acrylic acid ester polymers, and methacrylic acid ester polymers. The substrate sheet may be formed by using these resins alone or in combination of two or more.

[0050] The substrate sheet may be colored, and may contain various additives, such as fillers, matting agents, foaming agents, flame retardants, lubricants, antistatic agents, antioxidants, ultraviolet absorbers, light stabilizers, etc. The thickness of the substrate sheet can be appropriately set depending on the application and method of use of the final product, but is generally preferably 20 to 300 μm.

[0051] One or both sides of the base sheet may be subjected to a surface treatment such as corona discharge treatment, ozone treatment, plasma treatment, ionizing radiation treatment, dichromate treatment, etc. For example, when corona discharge treatment is performed, the surface tension of the base sheet surface may be set to 30 dyne or more, preferably 40 dyne or more. The surface treatment may be performed according to a conventional method for each treatment.

[0052] Examples of paper base materials for decorative sheets include paper sheets such as thin paper, plain paper, reinforced paper, and resin-impregnated paper, titanium paper, and the like.

[0053] The substrate may also be a wood veneer or the like that is commonly used for decorative boards. Examples of wood substrates for wood veneers include known substrates such as plywood, particle board, hardboard, and MDF that have been used as wooden substrates for decorative boards, furniture, building materials, etc. It does not matter what manufacturing method is used to obtain these known substrates. Further, examples of non-combustible materials that can be used as the substrate include perforated board building materials made from gypsum board, gypsum plate, calcium silicate plate, etc.; ceramic plates such as pottery, porcelain, stoneware, earthenware, glass, and enamel; and metal plates such as iron plate, galvanized steel plate, polyvinyl chloride sol-coated steel plate, aluminum plate, and copper plate.

[0054] (Process (I)) A coating film of the active energy ray-curable coating agent of the present invention is formed on a substrate selected according to the purpose of use by any of the coating methods described above.

[0055] (Step (II)) Next, the coating film is irradiated with active energy rays, which may be ultraviolet rays or electron beams. Ultraviolet light irradiation can be performed by a known method, for example, by irradiating ultraviolet light from a light source such as a germicidal lamp, an ultraviolet fluorescent lamp, an ultraviolet light emitting diode (UV-LED), a carbon arc, a metal halide lamp, a xenon lamp, a chemical lamp, a low pressure mercury lamp, a high pressure mercury lamp for copying, a medium or high pressure mercury lamp, an ultra-high pressure mercury lamp, an electrodeless lamp, a metal halide lamp, natural light, or the like. The cumulative amount of UV light is 20-1000mJ / cm 2 In order to maximize the effect of the present invention, it is preferable that the integrated light amount is within the range of 40 to 800 mJ / cm. 2 It is even more preferable that the range is: 20mJ / cm 2 If it is more than 1000mJ / cm, the curing efficiency is good.2 If it is below this level, damage to the substrate due to heat generation can be prevented.

[0056] On the other hand, when an electron beam is used, an electron beam irradiation device is used. The irradiation dose is preferably about 10 to 230 kGy, more preferably about 10 to 100 kGy. In the case of electron beam irradiation, the oxygen concentration in the atmosphere is preferably 2% or less.

[0057] The thickness of the coating film thus obtained is preferably in the range of 0.1 to 100 μm, and most preferably in the range of 0.5 to 50 μm. By keeping the thickness in this range, the effects of the present invention can be maximized.

[0058] Furthermore, the laminate using the active energy ray-curable coating agent of the present invention can be used not only for the above-mentioned building material applications such as decorative sheets, but also for a wide range of surface coating applications such as furniture, car interiors, musical instruments, office supplies, sporting goods, toys, etc. EXAMPLES

[0059] The present invention will be described in more detail below with reference to examples. In the examples, "parts" and "parts by mass" refer to mass %.

[0060] The average particle size of the glass beads and aluminosilicate was measured using a nanoparticle size distribution analyzer Nanotrac UPA EX-150 manufactured by Nikkiso Co., Ltd.

[0061] (Preparation of active energy ray curable coating agent) Example 1 20 parts by weight of multifunctional urethane (meth)acrylate oligomer (average number of acryloyl groups: 2, MIRAMER PU-2810, manufactured by MIWON Co., Ltd.), 10 parts by weight of multifunctional urethane (meth)acrylate oligomer (average number of acryloyl groups: 3, Beamset 550B, manufactured by Arakawa Chemical Industries Co., Ltd.), 20 parts by weight of multifunctional (meth)acrylate monomer (TPGDA, tripropylene glycol diacrylate, bifunctional monomer MIRAMER M-220, manufactured by MIWON Co., Ltd.), 50 parts by weight of multifunctional (meth)acrylate monomer (EO-TMPTA, ethylene oxide modified trimethylolpropane triacrylate, trifunctional monomer MIRAMER M-3130, manufactured by MIWON Co., Ltd.), photopolymerization initiator 1-hydroxy-cyclohexyl-phenyl-ketone "Omnirad An active energy ray-curable coating agent (1) was prepared by mixing and stirring a total of 139 parts by mass of 5 parts by mass of "IGM No. 184", 2 parts by mass of matting agent wet silica "Silysia 350" (Fuji Silysia Chemical Co., Ltd.), 2 parts by mass of glass beads (EMB-10, average particle size 5 μm, Potters Co., Ltd.), 15 parts by mass of methyl ethyl ketone, and 15 parts by mass of ethyl acetate with a stirrer for 1 hour. The storage modulus of the cured product obtained by curing the entire amount of the active energy ray-curable compound in this example, measured at 130° C., was 2.6×10 8 The strain at break was 2.3%.

[0062] [Examples 2 to 15, Comparative Examples 1 to 10] According to the formulations shown in Tables 1 to 5, each active energy ray-curable coating agent was prepared in the same manner as in Example 1. The storage modulus and breaking strain were also determined in the same manner.

[0063] <Formation of coating film by step (I)> A polypropylene film (manufactured by Okamoto Corp.) was used as a substrate, and the active energy ray curable coating agents prepared in Examples 1 to 15 and Comparative Examples 1 to 10 were each applied to the substrate in a film thickness of 10 μm using a bar coater.

[0064] <Ultraviolet ray irradiation in step (II)> Next, using a UV irradiation device (GS Yuasa Corporation) equipped with an air-cooled high-pressure mercury lamp (output 120 W / cm x 1 lamp) and a belt conveyor, the coated product was placed on the conveyor and passed directly under the lamp (irradiation distance 11 cm) in air at a speed of 25 meters per minute to harden the coating film. The UV exposure was measured at 60 mJ / cm using a UV integrating light meter (GS Yuasa Corporation's industrial UV checker UVR-N1). 2 It was confirmed that this was the case.

[0065] [Evaluation method] The active energy ray-curable coating agent of the present invention and the method for evaluating the prepared laminate will be described below.

[0066] [Evaluation item 1: Suitability for post-embossing] A post-embossing suitability test was conducted using an embossing machine. A convex embossing roll (wood grain pattern, depth: 50-100μm) was heated to 125-135℃ and pressed with a pressure of 10-20kN at a speed of 1m per minute to transfer the pattern, forming a concave-convex pattern on the coating surface. (Evaluation Criteria) ◯: No cracks were observed. ×: Cracks were observed.

[0067] [Evaluation item 2: Scratch resistance] A load of 1500 g was applied to the surface of the obtained coating film with steel wool ("BON STAR No. 0000" manufactured by Nippon Steel Wool Co., Ltd.) and the wool was moved back and forth 10 times, and the degree of damage to the coating film was evaluated on a four-level scale. (Evaluation Criteria) ⊚: No scratches or changes were observed. Good: The gloss of the friction surface changes, but no linear scratches are observed. △: Linear scratches occurred over less than 50% of the friction surface. ×: Linear scratches are present over 50% or more of the friction surface.

[0068] [Evaluation item 3: Scratch resistance] A test piece was prepared by adhering a coating film to a wooden plywood, and a Hoffman scratch test was carried out using a Gardner scratch tester. The load at which the coating film was scratched was evaluated on a four-point scale. (Evaluation Criteria) ◎: Scratches occurred at 300 grams or more. O: Scratches occurred at 250 grams. △: Scratches occurred at 200 grams. ×: Scratches occurred at less than 200 grams.

[0069] [Evaluation item 4: Chemical resistance] The coating film was observed after placing filter paper on the surface of the coating film, soaking it in chemicals, covering it with a watch glass, and leaving it for 24 hours. The chemicals used were petroleum benzine, naphtha, and lacquer thinner. After the test, the condition of the coating film was visually evaluated on a four-level scale. (Evaluation Criteria) ◎: No changes were observed for any of the drugs. ○: A change occurred for one drug. △: Changes occurred for two drugs. ×: Changes occurred for all drugs.

[0070] [Evaluation item 5: Stain resistance] The contaminants were applied to the surface of the coating film, left to stand for 24 hours, then wiped off with a cloth containing alcohol and visually observed for the degree of remaining contaminants. The contaminants used were blue ink, shoe polish, and curry. After the test, the state of contamination of the coating film was visually evaluated on a four-level scale. (Evaluation Criteria) ◎: No traces of any contaminants were found. ○: One contaminant remained. △: Two contaminants were found to remain. ×: All contaminants were found to remain.

[0071] [Evaluation item 6: Weather resistance] A metal halide lamp weather resistance test was conducted using an accelerated weather resistance tester, Eye UV Tester SUV-W262 (metal halide lamp), manufactured by Iwasaki Electric. The test conditions were irradiation temperature of 63°C and ultraviolet illuminance of 60mW / cm. 2 The cycle consisted of 20 hours of irradiation and 4 hours of condensation. The time it took for the coating film to change was visually observed and rated on a four-point scale. (Evaluation Criteria) ◎: No change for more than 360 hours. ○: Changes were observed between 240 hours and less than 360 hours. △: Changes were observed between 120 hours and less than 240 hours. ×: Changes were observed within 120 hours.

[0072] Tables 1 to 5 show the composition of each active energy ray-curable coating agent, the measured storage modulus E' and breaking strain, and the evaluation results of the produced laminates. In addition, all values ​​in the table are in parts by mass or mass %, and blank spaces indicate that no component was blended.

[0073] [Table 1]

[0074] [Table 2]

[0075] [Table 3]

[0076] [Table 4]

[0077] [Table 5]

[0078] The abbreviations in the table are as follows: ·MIRAMER PU-2810 Multifunctional urethane (meth)acrylate oligomer, average number of acryloyl groups: 2, manufactured by MIWON Beamset 550B Multifunctional urethane (meth)acrylate oligomer, average number of acryloyl groups: 3, manufactured by Arakawa Chemical Industries, Ltd. MIRAMER PU-610 Multifunctional urethane (meth)acrylate oligomer, average number of acryloyl groups: 6, manufactured by MIWON ·MIRAMER M-220 Bifunctional acrylate monomer, tripropylene glycol diacrylate (TPGDA), manufactured by MIWON ·MIRAMER M-3130 Trifunctional acrylate monomer, ethylene oxide modified trimethylolpropane triacrylate (EO-TMPTA), manufactured by MIWON Aronix M-930 Trifunctional acrylate monomer, glycerin triacrylate, manufactured by Toagosei Co., Ltd. Aronix M-460 4-functional acrylate monomer, ethylene oxide modified glycerin triacrylate, manufactured by Toagosei Co., Ltd. ·MIRAMER M-600 Hexafunctional acrylate monomer, dipentaerythritol hexaacrylate (DPHA), manufactured by MIWON Silica 350 Matte Silica, manufactured by Fuji Silysia Chemical Co., Ltd. EMB-10 glass beads, average particle size 5μm, Potters · Shilton JC-50 Aluminosilicate, average particle size 5μm, manufactured by Mizusawa Industrial Chemicals Co., Ltd. CAB-381-01 Cellulose acetate butyrate, manufactured by EASTMAN CHEMICAL Omnirad184 Photoinitiator 1-Hydroxy-cyclohexyl-phenyl-ketone, IGM Resins BV

Claims

1. An active energy ray-curable coating agent comprising an active energy ray-curable compound and inorganic fine particles, the active energy ray-curable coating agent satisfying (1), (2), and (3). (1) The active energy ray-curable compound contains a polyfunctional urethane (meth)acrylate oligomer (A) and a polyfunctional (meth)acrylate monomer (B). (2) The storage modulus of the cured product obtained by curing the entire amount of the active energy ray-curable compound is 1.0×10 ７ ~5.0 x 10 ８ Pa and the breaking strain is 1.5% to 5%. (3) As inorganic fine particles, silica (C) is contained in an amount of 1 to 20 mass % based on the total amount of the active energy ray-curable compound, and inorganic fine particles other than silica (D) are contained in an amount of 1 to 15 mass % based on the total amount of the active energy ray-curable compound.

2. 2. The active energy ray curable coating agent according to claim 1, comprising 35 to 80 mass% of the polyfunctional urethane (meth)acrylate oligomer (A) and 20 to 65 mass% of the polyfunctional (meth)acrylate monomer (B) based on the total amount of the active energy ray curable compounds.

3. The active energy ray-curable coating agent according to claim 1 , wherein the polyfunctional (meth)acrylate monomer (B) has a glycerin skeleton.

4. 2. The active energy ray-curable coating agent according to claim 1, wherein the inorganic fine particles (D) other than silica are aluminosilicate particles.

5. 2. The active energy ray-curable coating agent according to claim 1, further comprising, as weather resistance additives, an ultraviolet absorber (E) and a light stabilizer (F), each of which is present in an amount of 0.1 to 5 mass % based on the total amount of the active energy ray-curable compound.

6. 2. The active energy ray-curable coating agent according to claim 1, comprising 1 to 10 mass % of the cellulose-based resin (G) having a number average molecular weight of 10,000 to 80,000 based on the total amount of the active energy ray-curable compound.

7. A method for producing a laminate, comprising the steps of: (I) forming a coating film of an active energy ray-curable coating agent on a substrate; and (II) irradiating the coating film with active energy rays, in this order; wherein the active energy ray-curable coating agent is the active energy ray-curable coating agent according to any one of claims 1 to 6.

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