Photocurable resin composition, cured film, substrate with cured film, and method for producing the same.

Abstract

To provide a photocurable resin composition that can form a low-gloss cured film even when the substrate temperature is low during cured film formation. [Solution] A photocurable resin composition comprising a photocurable oligomer and / or photocurable resin (A), a (meth)acrylate monomer (B), a photopolymerization initiator (C), and spherical resin particles (D). (A) is a (meth)acrylate oligomer and / or (meth)acrylate resin having two or more (meth)acryloyl groups in one molecule, (D) comprises particles (D1) with an average particle size of 1.0 or more and less than 6.0 μm, and particles (D2) with an average particle size of 6.0 or more and 30 μm or less, the mass ratio of (D2) to (D1) is 3.5 or more and 20 or less, (A) is 5.0 or more and 30.0% by mass or less per 100% by mass of the photocurable resin composition, (B) is 20.0 or more and 70.0% by mass or less, and (C) is 0.1 or more and 10.0% by mass or less.

Description

[Technical Field]

[0001] The present invention relates to a photocurable resin composition. The present invention also relates to a cured film formed from the photocurable resin composition, a substrate with the cured film, and a method for producing the substrate with the cured film. [Background technology]

[0002] In recent years, there has been a growing demand for low-gloss finishes on interior materials (flooring, stairs, walls, etc.). In particular, there is a demand for low-gloss products that make the painted surface of the interior material less noticeable. Typically, this low gloss is evaluated by the gloss level (60-degree gloss) when light is incident on the coating surface at a 60-degree angle from a direction perpendicular to it.

[0003] For example, in order to improve the low gloss of a wood substrate, Patent Document 1 proposes using a photocurable resin composition containing a photocurable oligomer and / or photocurable resin (A), a (meth)acrylate monomer (B), a photopolymerization initiator (C), and urethane resin particles (D) having an average particle size in the range of 1 to 30 μm, wherein the urethane resin particles (D) include two or more types of particles with different average particle sizes. However, the cured film described in Patent Document 1 had room for improvement in terms of low gloss. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2021-084953 [Overview of the project] [Problems that the invention aims to solve]

[0005] The inventors have discovered a new problem: when the temperature of the substrate surface before application of the photocurable resin composition is high, it is easy to reduce the gloss of the cured film, whereas when the temperature of the substrate surface before application of the photocurable resin composition is low (for example, around 20 to 40 degrees Celsius), it is difficult to reduce the gloss of the cured film.

[0006] The present invention has been made in view of the above-mentioned background art and problems, and its object is to provide a photocurable resin composition that can form a low-gloss cured film even when the substrate temperature is low during cured film formation. [Means for solving the problem]

[0007] The present inventors, in order to solve the above problems, conducted diligent research and found that the above problems can be solved by blending two or more types of spherical resin particles with different average particle sizes in a specific ratio in a photocurable resin composition containing a photocurable oligomer and / or a photocurable resin, a (meth)acrylate monomer, and a photopolymerization initiator. The present invention was completed based on this finding.

[0008] In other words, the present invention provides the following invention. [1] A photocurable resin composition comprising a photocurable oligomer and / or photocurable resin (A), a (meth)acrylate monomer (B), a photopolymerization initiator (C), and spherical resin particles (D), The photocurable oligomer and / or photocurable resin (A) is a (meth)acrylate oligomer and / or (meth)acrylate resin having two or more (meth)acryloyl groups in one molecule, The (meth)acrylate monomer (B) is a photocurable (meth)acrylate compound, The spherical resin particles (D) include spherical resin particles (D1) with an average particle size of 1.0 μm or more and less than 6.0 μm, and spherical resin particles (D2) with an average particle size of 6.0 μm or more and 30 μm or less. The mass ratio of the spherical resin particles (D2) to the spherical resin particles (D1) is 3.5 or more and 20 or less. The content of the photocurable oligomer and the photocurable resin (A) is 5.0% by mass or more and 30.0% by mass or less based on 100% by mass of the photocurable resin composition. The content of the (meth)acrylate monomer (B) is 20.0% by mass or more and 70.0% by mass or less based on 100% by mass of the photocurable resin composition. A photocurable resin composition in which the content of the photopolymerization initiator (C) is 0.1% by mass or more and 10.0% by mass or less based on 100% by mass of the photocurable resin composition. [2] The photocurable resin composition according to [1], wherein the content of the spherical resin particles (D) is 5.0% by mass or more and 30.0% by mass or less based on 100% by mass of the photocurable resin composition. [3] The photocurable resin composition according to [1] or [2], wherein the spherical resin particles (D) are at least one selected from the group consisting of silicone resin fine particles, urethane resin fine particles, and acrylic resin fine particles. [4] The photocurable resin composition according to any one of [1] to [3], wherein the cured film formed from the photocurable resin composition has a 60-degree gloss of 5.0 or less. [5] The photocurable resin composition according to any one of [1] to [4], wherein the cured film formed from the photocurable resin composition has an 85-degree gloss of 10.0 or less. [6] A photocurable resin composition according to any one of [1] to [5], wherein the viscosity (KU value) at 25°C is 50 or more and 110 or less. [7] A photocurable resin composition according to any one of [1] to [6], used as a paint. [8] A cured film formed from any of the photocurable resin compositions described in [1] to [7]. [9] A substrate with a cured coating having a cured coating formed from any of the photocurable resin compositions described in [1] to [7] on at least a portion of the substrate surface.

[10] A coating step of applying a photocurable resin composition described in any of [1] to [7] to at least one surface of a substrate, After the coating step, a curing step is performed in which the photocurable resin composition is cured by ultraviolet irradiation to form a cured film, A method for producing a substrate with a cured coating, including the method described above. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a photocurable resin composition capable of forming a low-gloss cured film even when the substrate temperature during cured film formation is low. Further, according to the present invention, it is also possible to provide a cured film formed from such a photocurable resin composition, a substrate with the cured film, and a method for producing the substrate with the cured film.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, the present invention will be described in more detail. In this specification, “(meth)acrylate” represents acrylate and methacrylate, “(meth)acrylic” represents acrylic and methacrylic, and “(meth)acryloyl” represents acryloyl and methacryloyl.

[0011] <Photocurable Resin Composition> The photocurable resin composition according to the present invention contains a photocurable oligomer and / or a photocurable resin (A), a (meth)acrylate monomer (B), a photopolymerization initiator (C), and spherical resin particles (D). In the present invention, by using the photocurable resin composition containing the components (A) to (D), it is possible to form a low-gloss cured film even when the substrate temperature during cured film formation is low.

[0012] The viscosity (KU value) of the photocurable resin composition according to the present invention at 25°C is preferably 50 or more and 110 or less, more preferably 55 or more and 105 or less, and still more preferably 60 or more and 100 or less. If the viscosity (KU value) of the photocurable resin composition according to the present invention at 25°C is within the above numerical range, it is suitable as a paint because of its excellent coating workability. The viscosity (KU value) of the resin composition according to the present invention at 25°C is a value measured with a Stormer viscometer under the conditions described in JIS K 5600-2-2 (1999).

[0013] Hereinafter, each component constituting the photocurable resin composition will be described in detail. <0​​(Photocurable oligomers and photocurable resins (A)) The photocurable oligomer and photocurable resin (A) are (meth)acrylate oligomers and / or (meth)acrylate resins having two or more (meth)acryloyl groups in one molecule. Such photocurable oligomers and photocurable resins (A) can be obtained using a photocurable (meth)acrylate monomer having two or more (meth)acryloyl groups in one molecule.

[0015] Examples of photocurable (meth)acrylate monomers include urethane (meth)acrylate, polyester (meth)acrylate, polyether (meth)acrylate, epoxy (meth)acrylate, polybutadiene (meth)acrylate, and copolymerized (meth)acrylates in which an acryloyl group or methacryloyl group is introduced into the side chain of an acrylic acid ester copolymer. Among these, urethane (meth)acrylate is preferred. Photocurable (meth)acrylate monomers may be used alone or in combination of two or more types.

[0016] Examples of photocurable oligomers and photocurable resins include (meth)acrylate oligomers such as urethane (meth)acrylate oligomers, epoxy (meth)acrylate oligomers, polyester (meth)acrylate oligomers, and polyether (meth)acrylate oligomers, as well as (meth)acrylate resins such as urethane (meth)acrylate resins, epoxy (meth)acrylate resins, polyester (meth)acrylate resins, and polyether (meth)acrylate resins. Among these, urethane (meth)acrylate oligomers and resins are preferred. Photocurable oligomers and photocurable resins may be used individually or in combination of two or more types.

[0017] Examples of urethane (meth)acrylate oligomers and resins include those obtained by reacting an isocyanate compound with a hydroxyl group-containing (meth)acrylate compound and optionally a polyol compound. In particular, it is preferable to use a bifunctional or higher urethane (meth)acrylate oligomer or resin having two or more (meth)acryloyl groups.

[0018] Examples of the isocyanate compounds include polyisocyanates, specifically linear hydrocarbons containing isocyanate groups such as tetramethylene diisocyanate and hexamethylene diisocyanate [HDI], branched hydrocarbons containing isocyanate groups such as 2,2,4-trimethylhexamethylene diisocyanate [TMHMDI], cyclic hydrocarbons containing isocyanate groups such as isophorone diisocyanate [IPDI], hydrogenated diphenylmethane diisocyanate, hydrogenated xylene diisocyanate, and hydrogenated toluene diisocyanate, and p-phenylenediisocyanate. Examples include diisocyanate group-containing aromatic hydrocarbons such as phosphate [PPDI], 3,3'-dimethyldiphenyl-4,4'-diisocyanate [TODI], 1,3-xylene diisocyanate [XDI], dianisidine diisocyanate [DADI], tetramethylxylene diisocyanate [TMXDI], 1,5-naphthalene diisocyanate [NDI], tolylene diisocyanate [TDI], and 4,4-diphenylmethane diisocyanate [MDI]; and dimers or trimers of the aforementioned isocyanates (biuret modified, isocyanurate modified). Among these, hexamethylene diisocyanate [HDI] and isophorone diisocyanate [IPDI] are preferred as isocyanate compounds.

[0019] As the hydroxyl group-containing (meth)acrylate compound, a (meth)acrylate having one or more hydroxyl groups can be used, and one or more hydroxyl group-containing (meth)acrylate compounds may be used. Examples of the hydroxyl group-containing (meth)acrylate compounds include hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, hydroxyhexyl (meth)acrylate, and 2-hydroxy-3-chloropropyl (meth)acrylate. Examples include hydroxyl group-containing monofunctional (meth)acrylates such as polyethylene glycol mono(meth)acrylate and polypropylene glycol mono(meth)acrylate, trimethylolpropane di(meth)acrylate, glycerin di(meth)acrylate, pentaerythritol di or tri(meth)acrylate, diglycerin di or tri(meth)acrylate, ditrimethylolpropane di or tri(meth)acrylate, dipentaerythritol di, tri, tetra or penta(meth)acrylate, and hydroxyl group-containing polyfunctional (meth)acrylates. In addition, modified forms such as polycaprolactone-modified 2-hydroxyethyl (meth)acrylate may also be used.

[0020] As the polyol compound, known polyols such as polyether polyols, polyester polyols, and polyolefin polyols can be used, and specifically, examples include polyoxyethylene glycol, polyoxypropylene glycol, polyoxytetramethylene glycol, bisphenol A, hydrogenated bisphenol A, ethylene oxide adducts of bisphenol A, adducts of hydrogenated bisphenol A and ethylene oxide, propylene oxide adducts of bisphenol A, polycaprolactone diol, alkylene polyol, neopentyl glycol, 1,6-hexanediol, and trimethylolpropane. Such polyol compounds may be used individually or in combination of two or more.

[0021] From the viewpoint of the performance of the cured film, the content of the photocurable oligomer and photocurable resin (A) is 5.0% by mass or more and 30.0% by mass or less, preferably 10.0% by mass or more and 29.0% by mass or less, more preferably 15.0% by mass or more and 28.0% by mass or less, and even more preferably 20.0% by mass or more and 27.0% by mass or less, based on 100% by mass of the photocurable resin composition.

[0022] ((meth)acrylate monomer (B)) (Meth)acrylate monomer (B) is a photocurable (meth)acrylate compound having at least one (meth)acryloyl group, and forms a cured film when a photocurable resin composition is irradiated with ultraviolet light. Examples of (meth)acrylate monomers include monofunctional (meth)acrylate monomers and polyfunctional (meth)acrylate monomers. A polyfunctional (meth)acrylate monomer is a compound having two or more (meth)acryloyl groups as functional groups in its molecule.

[0023] Examples of monofunctional (meth)acrylate monomers include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, isomiristyl (meth)acrylate. Acrylate, alkyl (meth)acrylate (C12-C13, including mixtures of C12 and C13), cetyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, stearyl (meth)acrylate, diethylene glycol mono (meth)acrylate, dipropylene glycol mono (meth)acrylate, butoxyethyl (meth)acrylate, ethoxy-diethylene glycol (meth)acrylate, methoxyethylene glycol (meth) Acrylate, Methoxytriethylene glycol (meth)acrylate, Methoxypolyethylene glycol (meth)acrylate (n≒9), Methoxydipropylene glycol (meth)acrylate, Methoxytripropylene glycol (meth)acrylate, Dipropylene glycol (meth)acrylate, 2-Ethylhexyl diglycol (meth)acrylate, Cyclohexyl (meth)acrylate, Trimethylcyclohexyl (meth)acrylate, Benzyl (meth)acrylate, Phenoxyethyl (meth) Acrylate, phenoxy-polyethylene glycol (meth)acrylate, paracumylphenol EO modified (meth)acrylate, nonylphenol EO adduct (meth)acrylate (n≒1), nonylphenol EO adduct (meth)acrylate (n≒2), nonylphenol EO adduct (meth)acrylate (n≒4), nonylphenol EO adduct (meth)acrylate (n≒8), nonylphenol EO adduct (meth)acrylate (n≒16~17), nonylphenol PO modified (meth)acrylate (n≒2.5) Tetrahydrofurfuryl (meth)acrylate, isobornyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-hydroxy-3-butoxypropyl (meth)acrylate, 2-hydroxy-3-methoxypropyl (meth)acrylate, 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxyethyl phthalate, 2-(meth)acryloyloxypropyl hydrogen phthalate, 2-(meth)acryloyloxypropyl hexahydrohydrogen terephthalate, 2-(meth)acryloyloxypropyltetrahydrohydrohydrogen terephthalate, 2-(meth)acryloyloxyethyl-hexahydrophthalate, 2-(meth)acryloyloxyethyl-2-hydroxyethyl-phthalate, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate, 2-(meth)acryloyloxyethyl acid phosphate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylamide, trifluoroethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, octalfluoropentyl (meth)acrylate, perfluorooctylethyl (meth)acrylate, ω-carboxy-polycaprolactone (n≒2) mono(meth)acrylate, ( Examples include acrylate dimer (n≒1.4), N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, (meth)acryloylmorpholine, N-isopropyl(meth)acrylamide, N-2-hydroxyethyl(meth)acrylamide, caprolactone(meth)acrylate, neopentyl glycol(meth)acrylate benzoate, tribromophenyl(meth)acrylate, EO-modified tribromophenyl(meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl(meth)acrylate, (2-methyl-2-isobutyl-1,3-dioxolan-4-yl)methyl(meth)acrylate, isononyl(meth)acrylate, isostearyl(meth)acrylate, and t-butylcyclohexyl(meth)acrylate.

[0024] Examples of difunctional (meth)acrylate monomers include alkylene glycol di(meth)acrylates such as ethylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate and neopentyl glycol di(meth)acrylate; diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, dipropylene glycol di( Polyoxyalkylene glycol di(meth)acrylates such as meth)acrylate, tripropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate and polytetramethylene glycol di(meth)acrylate; halogen-substituted alkylene glycol di(meth)acrylates such as tetrafluoroethylene glycol di(meth)acrylate; trimethylolpropane di(meth)acrylate, ditrimethylolpropane di(meth)acrylate, penta-methyl Di(meth)acrylates of aliphatic polyols such as thritol di(meth)acrylate; di(meth)acrylates of hydrogenated dicyclopentadienyl di(meth)acrylate, tricyclodecanedimethanol di(meth)acrylate, and other hydrogenated dicyclopentadiene or tricyclodecanedialkanols; di(meth)acrylates of dioxane glycol or dioxanedialkanols such as 1,3-dioxane-2,5-diyl di(meth)acrylate; acrylic acid adducts of bisphenol A diglycidyl ether, bisphenol F diglycidyl ether Epoxy di(meth)acrylates of bisphenol A or bisphenol F such as acrylic acid adducts; silicone di(meth)acrylates; di(meth)acrylates of neopentyl glycol hydroxypivalate; 2,2-bis[4-(meth)acryloyloxyethoxyethoxyphenyl]propane; 2,2-bis[4-(meth)acryloyloxyethoxyethoxycyclohexyl]propane; di(meth)acrylates of 2-(2-hydroxy-1,1-dimethylethyl)-5-ethyl-5-hydroxymethyl-1,3-dioxane;Examples include tris(hydroxyethyl) isocyanurate di(meth)acrylate; these may be used individually or in combination of two or more.

[0025] Examples of polyfunctional (meth)acrylate monomers with three or more functions include glycerin tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and other poly(meth)acrylates of trivalent or higher aliphatic polyols. These may be used individually or in combination of two or more.

[0026] It is preferable to use a polyfunctional (meth)acrylate monomer obtained by adding alkylene oxide to the above-mentioned bifunctional or more functional (meth)acrylate monomer, and more preferable to a polyfunctional (meth)acrylate monomer obtained by adding ethylene oxide.

[0027] From the viewpoint of the performance of the cured film, the content of (meth)acrylate monomer (B) is 20.0% by mass or more and 70.0% by mass or less per 100% by mass of the photocurable resin composition, preferably 30.0% by mass or more and 65.0% by mass or less, more preferably 40.0% by mass or more and 60.0% by mass or less, and even more preferably 45.0% by mass or more and 55.0% by mass or less.

[0028] (Photopolymerization initiator (C)) The photopolymerization initiator is not particularly limited, and conventionally known photopolymerization initiators for photocurable resin compositions can be used. Examples of photopolymerization initiators include acylphosphine oxide-based polymerization initiators, acetophenone-based polymerization initiators, benzoyl formate-based polymerization initiators, thioxanthone-based polymerization initiators, oxime ester-based polymerization initiators, hydroxybenzoyl-based polymerization initiators, benzophenone-based polymerization initiators, and α-aminoalkylphenone-based polymerization initiators.

[0029] Examples of acylphosphine oxide polymerization initiators include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide, and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide. Examples of acetophenone-based polymerization initiators include acetophenone, 3-methylacetophenone, benzyldimethyl ketal, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, and 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)benzyl]phenyl}-2-methylpropan-1-one. Examples of benzoylformate polymerization initiators include methylbenzoylformate. Examples of thioxanthone-based polymerization initiators include isopropylthioxanthone. Examples of oxime ester polymerization initiators include 2-[(benzoyloxy)imino]-1-[4-(phenylthio)phenyl]octan-1-one and 1-[9-ethyl-6-(2-methylbenzoyl)carbazole-3-yl]-3-(cyclopentyl)propan-1-one O-acetyloxime. Examples of hydroxybenzoyl polymerization initiators include benzoin alkyl ethers and the like. Examples of benzophenone-based polymerization initiators include benzophenone, 4-chlorobenzophenone, and 4,4'-diaminobenzophenone. Examples of α-aminoalkylphenone polymerization initiators include 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one and 2-benzyl-2-(N,N-dimethylamino)-1-(4-morpholinophenyl)butan-1-one. These polymerization initiators may be used individually or in combination of two or more.

[0030] The content of the photopolymerization initiator (C) is, from the viewpoint of the curability of the photocurable resin composition and the performance of the cured film, 0.1% by mass or more and 10.0% by mass or less, preferably 0.5% by mass or more and 9.0% by mass or less, more preferably 1.0% by mass or more and 8.0% by mass or less, and even more preferably 2.0% by mass or more and 7.0% by mass or less, relative to the resin solids.

[0031] (Spherical resin particles (D)) The spherical resin particles (D) include spherical resin particles (D1) with an average particle size of 1.0 μm or more and less than 6.0 μm, and spherical resin particles (D2) with an average particle size of 6.0 μm or more and 30 μm or less. The average particle size of the spherical resin particles (D1) is preferably 1.2 μm or more and 5.8 μm or less, more preferably 1.5 μm or more and 5.5 μm or less, and even more preferably 2.0 μm or more and 5.0 μm or less. The average particle size of the spherical resin particles (D2) is preferably 6.2 μm to 28 μm, more preferably 6.4 μm to 26 μm, and even more preferably 6.5 μm to 25 μm. The average particle size of spherical resin particles (D1) and spherical resin particles (D2) was measured by laser diffraction / scattering. 50This is the value, and can be measured, for example, using a laser diffraction / scattering particle size distribution analyzer "Microtrac MT3000II" (manufactured by Microtrac-Bell).

[0032] The type of spherical resin particles (D) is not particularly limited, and conventionally known spherical resin particles can be used, but examples include silicone resin fine particles, urethane resin fine particles, and acrylic resin fine particles. The types of spherical resin particles (D1) and spherical resin particles (D2) may be the same or different.

[0033] The mass ratio (D2 / D1) of spherical resin particles (D2) to spherical resin particles (D1) is 3.5 to 20, preferably 3.7 to 19, and more preferably 3.9 to 18, from the viewpoint of reducing the gloss of the cured film. From the viewpoint of reducing the gloss of the cured film, the content of spherical resin particles (D) is preferably 5.0% to 30.0% by mass, more preferably 7.0% to 28.0% by mass, and even more preferably 10.0% to 25.0% by mass, based on 100% by mass of the photocurable resin composition.

[0034] (Other ingredients) The photocurable resin composition according to the present invention may contain other components besides the above components (A) to (D), as long as the objectives of the present invention are not impaired. Other components that may be added as needed include leveling agents, dispersants, antioxidants, antistatic agents, ultraviolet absorbers, light stabilizers, polymerization inhibitors, non-reactive diluents, inorganic matting agents, defoaming agents, settling inhibitors, heat stabilizers, adhesion enhancers, photosensitizers, antibacterial agents, antifungal agents, antiviral agents, anti-allergic agents, silane coupling agents, plasticizers, etc.

[0035] The photocurable resin composition according to the present invention may be either a solvent-type resin composition that is diluted with a non-reactive diluent (organic solvent), or a solvent-free resin composition that does not require dilution with an organic solvent. However, a solvent-free resin composition is preferred because it does not leave any residue of volatile organic compounds (VOCs), thus having no impact on the human body and being environmentally friendly.

[0036] <Method for preparing a photocurable resin composition> The photocurable resin composition according to the present invention is obtained by mixing and stirring the above components using conventionally known devices such as mixers, dispersers, and stirrers. Examples of such devices include mixing and dispersing mills, homodispersers, mortar mixers, rolls, paint shakers, and homogenizers.

[0037] <Cured film> The cured film according to the present invention is formed from the above-described photocurable resin composition. By using the above-described photocurable resin composition, a low-gloss cured film can be achieved while maintaining a constant film thickness, even when the substrate temperature is low during cured film formation. The cured film according to the present invention preferably has a 60-degree gloss of 5.0 or less, more preferably 4.5 or less, and even more preferably 4.0 or less, and an 85-degree gloss of preferably 10.0 or less, more preferably 9.0 or less, and even more preferably 8.0 or less. The 60-degree gloss and 85-degree gloss of the cured film are values ​​measured by the method described in the examples.

[0038] The thickness of the cured film is not particularly limited, but is preferably 1 μm to 100 μm, more preferably 2 μm to 80 μm, even more preferably 3 μm to 60 μm, even more preferably 4 μm to 40 μm, and most preferably 5 μm to 20 μm. In this invention, "film thickness" refers to the thickness of the cured film when its cross-section is observed with an optical microscope or a scanning electron microscope (SEM). When forming a film of such thickness, the desired thickness may be formed in a single coating, or it may be formed in multiple coatings.

[0039] <Substrate with hardened film> The substrate with a cured film according to the present invention has a cured film formed from the above-mentioned photocurable resin composition on at least a portion of the substrate surface. The cured film may be provided on the entire surface of one side of the substrate, on only a portion of one side, or on both sides of the substrate. When provided on only a portion, the form of the cured film is not particularly limited, and any form such as a sea-island-like sea portion or island portion, a grid shape, or a mosaic shape can be adopted without particular limitation.

[0040] (base material) The base material is not particularly limited, and conventionally known base materials for interior materials can be used. Examples of base materials include wood-based base materials and base materials made of synthetic resins. Examples of wood-based base materials include plywood, solid wood, hardboard, particleboard, etc. Examples of synthetic resins include thermoplastic resins and thermosetting resins. Specific examples of thermoplastic resins include polyvinyl chloride resins, polyolefin resins, polystyrene resins, polyester resins, acrylic resins, etc. Specific examples of thermosetting resins include phenolic resins, epoxy resins, urethane resins, urea resins, melamine resins, etc. Among these, it is preferable to use a wood-based base material. The thickness of the base material is not particularly limited, but is preferably 0.2 to 50 mm, and more preferably 1 to 20 mm.

[0041] <Method for manufacturing a substrate with a hardened coating> The method for producing a substrate with a cured film according to the present invention comprises a coating step of applying the above-mentioned photocurable resin composition to at least one surface of the substrate, After the coating step, a curing step is performed in which the above photocurable lipid composition is cured by ultraviolet irradiation to form a cured film, This includes the following. Each step will be explained in detail below.

[0042] (Coating process) The coating step involves applying the above-mentioned photocurable resin composition to at least one surface of the substrate using a conventionally known method. For coating, coating machines such as bar coaters, gravure coaters, roll coaters (natural roll coaters and reverse roll coaters, etc.), air knife coaters, spin coaters, and blade coaters can be used. Among these, a coating method using a roll coater is preferred from the viewpoint of workability and productivity.

[0043] The coating thickness is not particularly limited and is appropriately selected depending on the type of substrate. Preferably, the coating thickness after curing and drying is within the range of the cured film thickness mentioned above.

[0044] When the resin composition is used after being diluted with a solvent, it is preferable to dry it after application. Examples of drying methods include hot air drying (e.g., using a hair dryer). The drying temperature is preferably 10 to 200°C, with a more preferable upper limit of 150°C from the viewpoint of film smoothness and appearance, and a more preferable lower limit of 30°C from the viewpoint of drying speed.

[0045] (hardening process) The curing process involves irradiating the coated surface of the substrate with ultraviolet light to cure the applied photocurable resin composition and form a cured film. Methods for curing with ultraviolet light include using high-pressure mercury lamps, metal halide lamps, xenon lamps, chemical lamps, UV-LEDs, etc., that emit light in the 200-500 nm wavelength range. To suppress curing inhibition by oxygen, ultraviolet irradiation can be carried out under an inert gas atmosphere such as nitrogen or argon, if necessary. From the viewpoint of the curability of the photocurable resin composition and the flexibility of the cured product, the amount of ultraviolet irradiation is preferably 100-3,000 mJ / cm². 2 And more preferably 200 to 1,000 mJ / cm² 2 That is the case. [Examples]

[0046] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0047] First, the following materials were prepared for the photocurable resin composition. (A) Photocurable oligomer 1:2 functional urethane (meth)acrylate oligomer, manufactured by Mitsubishi Chemical Corporation, product name: Shiko UV-6640B • (A) Photocurable oligomer 2:6 functional urethane (meth)acrylate oligomer, manufactured by Mitsubishi Chemical Corporation, product name: Shiko UV-7600B • (B) (Meth)acrylate monomer 1: No EO addition, bifunctional, polypropylene glucose diacrylate (TPGDA), manufactured by Toagosei Co., Ltd., product name: Arronix M-220 • (B) (meth)acrylate monomer 2:2 functional, EO-modified 1,6-hexanediol diacrylate (1,6-HD(EO)DA), manufactured by Miwon Co., Ltd., product name: MIRAMER M-202 • (B)(meth)acrylate monomer 3:3 functional, EO-modified trimethylolpropane triacrylate (TMP(EO)TA), manufactured by Miwon Co., Ltd., product name: MIRAMER M-3130 • (C) Photopolymerization initiator (1-hydroxycyclohexylphenyl ketone, manufactured by IGM Resin, trade name: Omnirad 184) • (D1) Silicone resin beads: Average particle size (D 50 ) 2.0μm, manufactured by Aica Kogyo Co., Ltd., product name: Gantz Pearl SI-020 • (D1) Urethane resin beads 1: Average particle size (D 50 )3.5μm, manufactured by Negami Kogyo Co., Ltd., product name: ART PEARL CE-1000T • (D1) Acrylic resin beads 1: Average particle size (D 50 ) 4.0μm, manufactured by Aica Kogyo Co., Ltd., product name: Gantz Pearl GM-0401S • (D2) Urethane resin beads 2: Average particle size (D 50 )6.5μm, manufactured by Negami Kogyo Co., Ltd., product name: ART PEARL C-800T • (D2) Urethane resin beads 3: Average particle size (D 50) 10.5 μm, manufactured by Negami Kogyo Co., Ltd., product name: ART PEARL C-600T · (D2) Urethane resin beads 4: average particle size (D 50 ) 16.0 μm, manufactured by Negami Kogyo Co., Ltd., product name: ART PEARL C-400T · (D2) Acrylic resin beads 2: average particle size (D 50 ) 10.5 μm, manufactured by Aika Kogyo Co., Ltd., product name: Gantz Pearl GM-1001 · (D2) Acrylic resin beads 3: average particle size (D 50 ) 20.0 μm, manufactured by Aika Kogyo Co., Ltd., product name: Gantz Pearl GM-2001

[0048] [Examples 1 - 8, Comparative Examples 1 - 6] [Preparation of photocurable resin composition] According to the formulations described in Tables 1 and 2, each component was mixed to obtain a photocurable resin composition.

[0049] (Viscosity of photocurable resin composition) The viscosity (KU value) at 25 °C of each of the photocurable resin compositions prepared above was measured using a Stormer viscometer in accordance with the provisions of JIS K 5600-2-**2**(1999). The measurement results are shown in Tables 3 and 4. Note that if the viscosity (KU value) is in the range of 50 - 110, it is suitable as a paint because of its excellent coating workability.

[0050] [Manufacture A of substrate with cured film] A black polyester resin decorative plywood of a phenolic resin laminated plywood was prepared as the substrate. Next, after adjusting the temperature of the substrate surface to 25 °C, each of the photocurable resin compositions prepared above was applied onto the substrate at 1.0 g / ft 2 using a natural roll coater and dried. The dry film thickness of the film was about 10 μm. Subsequently, UV irradiation (integrated illuminance 400 mJ / cm 2 , light quantity 250 mW / cm 2 ) was performed on the coated surface of the substrate using a high-pressure mercury lamp to cure the film and form a cured film, and a substrate A with a cured film was obtained.

[0051] It should be noted that there seems to be a small error in the original text where "JIS K 5600-2-2(1999)" has an extra asterisk in the English translation. I've removed it as it's likely a typo. If this is not what you intended, please let me know. [Manufacturing of substrates with cured coatings B] A cured coated substrate B was obtained in the same manner as in [Manufacturing of Cured Coating Substrate 1], except that the surface temperature of the substrate was adjusted to 50°C.

[0052] (Specular gloss) The 60-degree gloss and 85-degree gloss of the cured film surface of each cured film-coated substrate A and B manufactured as described above were measured using a gloss meter (micro-TRI-gloss, BYK-Grdner). The measurement results are shown in Tables 3 and 4. Note that the 60-degree gloss and 85-degree gloss values ​​are measured by receiving light incident on the cured film surface at an angle of 60 or 85 degrees perpendicular to the cured film surface, and receiving the light at an angle of 60 or 85 degrees perpendicular to the cured film surface. If the 60-degree gloss value is 5.0 or less and the 85-degree gloss value is 10.0 or less, the cured film can be said to have low gloss. On the other hand, if the 60-degree gloss value is greater than 5.0 or the 85-degree gloss value is greater than 10.0, the cured film can be said to have no low gloss.

[0053] [Table 1]

[0054] [Table 2]

[0055] [Table 3]

[0056] [Table 4]

Claims

1. A photocurable resin composition comprising a photocurable oligomer and / or a photocurable resin (A), a (meth)acrylate monomer (B), a photopolymerization initiator (C), and spherical resin particles (D), The photocurable oligomer and / or photocurable resin (A) is a (meth)acrylate oligomer and / or (meth)acrylate resin having two or more (meth)acryloyl groups in one molecule, The (meth)acrylate monomer (B) is a photocurable (meth)acrylate compound, The spherical resin particles (D) include spherical resin particles (D1) with an average particle size of 1.0 μm or more and less than 6.0 μm, and spherical resin particles (D2) with an average particle size of 6.0 μm or more and 30 μm or less. The mass ratio of the spherical resin particles (D2) to the spherical resin particles (D1) is 3.5 or more and 20 or less. The content of the photocurable oligomer and the photocurable resin (A) is 5.0% by mass or more and 30.0% by mass or less based on 100% by mass of the photocurable resin composition. The content of the (meth)acrylate monomer (B) is 20.0% by mass or more and 70.0% by mass or less based on 100% by mass of the photocurable resin composition. A photocurable resin composition in which the content of the photopolymerization initiator (C) is 0.1% by mass or more and 10.0% by mass or less based on 100% by mass of the photocurable resin composition.

2. The photocurable resin composition according to claim 1, wherein the content of the spherical resin particles (D) is 5.0% by mass or more and 30.0% by mass or less based on 100% by mass of the photocurable resin composition.

3. The photocurable resin composition according to claim 1, wherein the spherical resin particles (D) are at least one selected from the group consisting of silicone resin fine particles, urethane resin fine particles, and acrylic resin fine particles.

4. The photocurable resin composition according to claim 1, wherein the cured film formed from the photocurable resin composition has a 60-degree gloss of 5.0 or less.

5. The photocurable resin composition according to claim 1, wherein the cured film formed from the photocurable resin composition has an 85-degree gloss of 10.0 or less.

6. The photocurable resin composition according to claim 1, wherein the viscosity (KU value) at 25°C is 50 or more and 110 or less.

7. A photocurable resin composition according to claim 1, used as a paint.

8. A cured film formed from the photocurable resin composition according to any one of claims 1 to 7.

9. A substrate with a cured coating having a cured coating formed from the photocurable resin composition described in any one of claims 1 to 7 on at least a portion of the substrate surface.

10. A coating step of applying the photocurable resin composition according to any one of claims 1 to 7 to at least one surface of a substrate, After the coating step, a curing step is performed in which the photocurable resin composition is cured by ultraviolet irradiation to form a cured film, A method for producing a substrate with a cured coating, including the method described above.

Images