Photocurable coating compositions and coated articles

Abstract

To provide a photocurable coating composition that imparts a coating that exhibits excellent scratch resistance, water repellency, and antifouling property, and can maintain these properties in long outdoor use.SOLUTION: A) Organopolysiloxane represented by a formula (1) (R1 independently represents a monovalent hydrocarbon group in which a hydrogen atom or an oxygen atom, etc., may be present; X independently represents a divalent saturated hydrocarbon group which may contain an oxygen atom, etc.,; Q independently represents an (a+1)-valent saturated hydrocarbon group which may contain an oxygen atom, etc.,; P independently represents an acryloyloxy group or a methacryloyloxy group; a each independently represents an integer of 2 to 5; and n represents an integer of 0 to 100.) (B) an ultraviolet absorber and (C) a photopolymerization initiator, and a content of the (A) component in terms of the nonvolatile component is 30 to 99 mass%.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to photocurable coating compositions and coated articles. [Background technology]

[0002] In recent years, there has been a demand for curable compositions that can form cured films having excellent coatability, appearance, transparency, scratch resistance, surface slippage, low curling, adhesion, chemical resistance, and the like, and that can be used as protective coatings for the surfaces of various substrates such as various plastics (polycarbonate, polymethyl methacrylate, polystyrene, polyester, polyolefin, epoxy resin, melamine resin, triacetyl cellulose resin, ABS resin, AS resin, norbornene-based resin, etc.), metal, wood, etc., and that are capable of forming cured films having excellent weather resistance. Furthermore, it is desirable to have the above properties satisfied by a photocurable composition that can be cured in a short time with less energy than a heat-curable composition, which takes a relatively long time to cure and requires a lot of energy.

[0003] A well-known example of a typical photocurable coating composition is a photocurable (meth)acrylic composition that uses a multifunctional (meth)acrylate. The photocurable (meth)acrylic composition contains one or more multifunctional (meth)acrylates and a photopolymerization initiator, and forms a coating by crosslinking through photopolymerization of the (meth)acrylic groups in the multifunctional (meth)acrylate, thereby exhibiting excellent curability, scratch resistance, hardness, and chemical resistance.

[0004] By blending these photocurable (meth)acrylic coating compositions with a fluorine-based additive having perfluoropolyether groups and (meth)acrylic groups as water-repellent and antifouling groups, it is possible to obtain coatings that have the above properties as well as water-repellent and antifouling properties (Patent Documents 1 to 3). Another known fluorine-based additive is a compound in which cyclic polysiloxanes are linked by divalent perfluoropolyether chains (Patent Document 4).

[0005] Furthermore, curable compositions are known that have improved slip properties and the ability to wipe off fingerprints and oily dyes by blending a small amount of polysiloxane having a (meth)acryloyl group (Patent Documents 5 to 7). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-145884 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-53114 [Patent Document 3] Japanese Patent Application Laid-Open No. 2010-138112 [Patent Document 4] Japanese Patent Application Laid-Open No. 2010-285501 [Patent Document 5] Patent No. 4910253 [Patent Document 6] Japanese Patent Application Laid-Open No. 2005-036018 [Patent Document 7] Japanese Patent Application Laid-Open No. 2008-081575 Summary of the Invention [Problem to be solved by the invention]

[0007] On the other hand, photocurable (meth)acrylic coating compositions also have a problem of improving weather resistance, particularly for outdoor applications.

[0008] The present invention has been made in view of the above circumstances, and aims to provide a photocurable coating composition and a coated article which provide a coating that exhibits excellent scratch resistance, water repellency, and stain resistance, and which maintains these properties even after long-term outdoor use. [Means for solving the problem]

[0009] The present inventors have conducted extensive research to achieve the above-mentioned object, and as a result have found that a photocurable coating composition containing the following components (A) to (C) provides a coating film having excellent scratch resistance, water repellency, and stain resistance, and that these properties are maintained even after a weather resistance test, thereby completing the present invention.

[0010] That is, the present invention is 1. (A) an organopolysiloxane represented by the following formula (1): [ka] (In the formula, R 1 each independently represents a hydrogen atom or a monovalent hydrocarbon group optionally interrupted by an oxygen atom, X's each independently represent a divalent saturated hydrocarbon group optionally interrupted by one or more atoms selected from oxygen, nitrogen, sulfur, and phosphorus; Q's each independently represent an (a+1)-valent saturated hydrocarbon group optionally interrupted by one or more atoms selected from oxygen, nitrogen, sulfur, phosphorus, and silicon; P's are each independently an acryloyloxy group or a methacryloyloxy group; a's each independently represent an integer of 2 to 5; n represents an integer from 0 to 100. (B) an ultraviolet absorber, and (C) Photopolymerization initiator a photocurable coating composition containing the above, wherein the content of component (A) in terms of nonvolatile content is 30 to 99 mass %; 2. The above R 1 is a methyl group; 3. The photocurable coating composition according to 1, wherein each X is independently a divalent saturated hydrocarbon group having 2 to 30 carbon atoms, optionally interrupted by an oxygen atom. 4. The photocurable coating composition of 3, wherein X is a group represented by the following formula (2): [ka] (In the formula, *1 is bonded to the silicon atom of the formula (1), * 2 is bonded to the oxygen atom in the urethane group of the formula (1). 5. The photocurable coating composition according to 1, wherein each Q is independently a saturated hydrocarbon group having a urethane bond, a valence of (a+1), and carbon atoms of 4 to 30. 6. The photocurable coating composition 1, wherein n is an integer of 1 to 80. 7. The photocurable coating composition according to 1, wherein the component (B) is an ultraviolet absorber having a (meth)acryloyl group. 8. (D) A photocurable coating composition comprising one or more selected from organopolysiloxanes having (meth)acryloyl groups but not having urethane bonds, and silica particles surface-modified with alkoxysilanes having (meth)acryloyl groups but not having urethane bonds; 9. The photocurable coating composition of 1 containing (E) a (meth)acrylate compound having no silicon atom (excluding the component (B)). 10. A cured film of the photocurable coating composition of any one of 1 to 9. 11. A coated article comprising a substrate and a cured film of the photocurable coating composition of 10 formed on the substrate directly or via at least one other layer. 12. The coated article according to claim 11, wherein the substrate is an organic resin or wood. to provide. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a photocurable coating composition that gives a coating film that exhibits excellent scratch resistance, water repellency, and stain resistance, and that maintains these properties even when used outdoors for a long period of time. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will be specifically described below. The photocurable coating composition of the present invention comprises (A) an organopolysiloxane having a plurality of (meth)acryloyl groups at both ends thereof via urethane bonds, (B) an ultraviolet absorber, and (C) a photopolymerization initiator.

[0013] [1] Component (A) Component (A) is an organopolysiloxane represented by the following general formula (1).

[0014] [ka]

[0015] In formula (1), R 1 each independently represent a hydrogen atom or a monovalent hydrocarbon group which may be interrupted by an oxygen atom; each X independently represent a divalent saturated hydrocarbon group which may be interrupted by one or more atoms selected from oxygen, nitrogen, sulfur, and phosphorus; each Q independently represent an (a+1)-valent saturated hydrocarbon group which may be interrupted by one or more atoms selected from oxygen, nitrogen, sulfur, phosphorus, and silicon; each P independently represent an acryloyloxy group or a methacryloyloxy group; each a independently represent an integer of 2 to 5; and n independently represent an integer of 0 to 100.

[0016] Above R 1 The monovalent hydrocarbon group may be straight-chain, branched, or cyclic, but preferably has 1 to 20 carbon atoms. Specific examples thereof include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-hexyl, cyclohexyl, n-octyl, 2-ethylhexyl, and n-decyl; alkenyl groups such as vinyl, allyl (2-propenyl), 1-propenyl, isopropenyl, and butenyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; and aralkyl groups such as benzyl, phenylethyl, and phenylpropyl. Among these, R 1is preferably a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 12 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms, even more preferably an alkyl group having 1 to 5 carbon atoms, and still more preferably a methyl group. The monovalent hydrocarbon group may have an oxygen atom present within the molecular chain or at the Si terminal, and may be, for example, an alkoxy group having 1 to 20 carbon atoms.

[0017] The divalent saturated hydrocarbon group of X, which may be interrupted by at least one atom selected from oxygen, nitrogen, sulfur, and phosphorus atoms, may be linear, branched, or cyclic, but is preferably an alkylene group having 1 to 20 carbon atoms, an oxyalkylene group having 1 to 20 carbon atoms, or a polyoxyalkylene group having 1 to 20 carbon atoms. Among these, in consideration of ease of synthesis and availability of raw materials, a group represented by the following formula (2) is more preferred.

[0018] [ka] (In the formula, * 1 is bonded to the silicon atom of formula (1), * 2 is bonded to the oxygen atom in the urethane group of formula (1).

[0019] The (a+1)-valent, preferably trivalent to hexavalent, saturated hydrocarbon group of Q, which may be interrupted by at least one atom selected from oxygen, nitrogen, sulfur, phosphorus, and silicon, may be either branched or cyclic, and examples thereof include branched trivalent saturated hydrocarbon groups having 1 to 10 carbon atoms, such as -CH<, -CH2CH<, -CH(CH3)CH<, and -C(CH3)(CH2-)2; -(CH2)6-NHCO-OR 2 (-) c , -CH2CH(CH3)CH2C(CH3)2CH2CH2-NHCO-OR 2 (-) c , -CH2C(CH3)2CH2CH(CH3)CH2CH2-NHCO-OR 2 (-) c , -R 3 -NHCO-OR 2 (-) cExamples of the saturated hydrocarbon groups include branched or cyclic trivalent to hexavalent hydrocarbon groups having 4 to 30 carbon atoms and containing a urethane bond, such as those described above. Note that < indicates that there are two bonds, and c indicates that R 2 represents the number of P bonded to and is an integer of 2 to 5.

[0020] Above R 2 is preferably a branched or cyclic trivalent to hexavalent saturated hydrocarbon group optionally containing oxygen and nitrogen atoms. Specific examples thereof include -CH(CH2-)2, -CH2-C(CH2-)3, and -(CH2CH2O) d -CH2C(CH2-)3, -(CH2CH2O) d -CH2C(CH2-(OCH2CH2) d -)3, -(CH2CH(CH3)O) d -CH2C(CH2-(OCH(CH3)CH2) d -), -CH2CH2-Z-(CH2CH2-)2, -CH2CH2-Z-(CH2CH2-)2, -CH2CH2-Z-(CH2CH2-)2, -CH2CH2-Z-(CH2CHO-C(=O)(CH2)5-O-)2, -CH2-C(CH2-)2-CH2OCH2-C(CH2-)3, etc., where Z is an isocyanurate skeleton residue [*3-NC(=O)NC(=O)NC(=O)-*4], * 3 and * 4 are bonded to each other to form a ring structure. Above R 3 is preferably a cyclic tri- to hexavalent saturated hydrocarbon group having 10 to 30 carbon atoms which may be interrupted by oxygen or nitrogen atoms, and more preferably a residue of isophorone diisocyanate in which two isocyanate groups have been removed. Among these, in consideration of ease of synthesis and availability of raw materials, Q is more preferably a group represented by the following formulae (3) to (12).

[0021] [ka]

[0022] [ka]

[0023] [ka]

[0024] [ka]

[0025] [ka]

[0026] [ka]

[0027] [ka]

[0028] [ka]

[0029] [ka]

[0030] [ka]

[0031] In formulas (3) to (12), * 5 is bonded to P in formula (1), * 6 is bonded to the nitrogen atom in the urethane group of formula (1).

[0032] In formula (1), a represents the number of Ps bonded to Q and is an integer of 2 to 5, preferably an integer of 3 to 5. If a is less than 2, the curability of the composition and the scratch resistance of the resulting coating film may be insufficient, and if it exceeds 5, the coating film may have poor crack resistance. n is an integer of 0 to 100, preferably an integer of 1 to 80, and more preferably an integer of 3 to 60. If n exceeds 100, the coating properties may deteriorate and the coating film may have poor appearance such as uneven coating.

[0033] The content of component (A) is in the range of 30 to 99% by mass, preferably 35 to 80% by mass, based on the nonvolatile content of the entire composition. If it is less than 30% by mass, the resulting cured coating film may have poor water repellency and stain resistance and may not exhibit sufficient weather resistance, while if it exceeds 99% by mass, the resulting cured coating film may have reduced adhesion to the substrate.

[0034] [2](B) Component Component (B) is an ultraviolet absorber, and is not particularly limited as long as it absorbs ultraviolet light, but examples thereof include hydroxybenzophenones, hydroxybenzotriazoles, and hydroxyphenyltriazines. Specific examples thereof include 2,4-dihydroxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-n-dodecyloxybenzophenone, 2-hydroxy-4-n-benzyloxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2'-dihydroxy-4,4'-diethoxybenzophenone, 2,2'-dihydroxy-4,4'-dipropoxybenzophenone, 2,2'-dihydroxy-4,4'-dibutoxybenzophenone, 2,2'-dihydroxy-4-methoxy-4'-propoxybenzophenone, 2,2'-dihydroxy-4-methoxy-4'-butoxybenzophenone, 2,3,4 -trihydroxybenzophenone, 2-(2-hydroxy-5-t-methylphenyl)benzotriazole, 2-(2-hydroxy-5-t-octylphenyl)benzotriazole, 2-(2-hydroxy-3,5-di-t-butylphenyl)benzotriazole, ethyl-2-cyano-3,3-diphenylacrylate, 2-ethylhexyl-2-cyano-3,3-diphenylacrylate, 2-(2-hydroxy-4-hexyloxyphenyl)-4,6-diphenyltriazine, 2-[4-[(2-hydroxy-3-(2'-ethyl)hexyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine), 2-[2-hydroxy-4-(1-octyloxycarbonylethoxy)phenyl]-4,6-bis(4-phenylphenyl)-1,3,5-triazine], and the like.

[0035] As component (B), an ultraviolet absorber containing a (meth)acryloyloxy group is preferred. Such an ultraviolet absorber forms crosslinks with component (A) and other (meth)acrylate compounds, and is incorporated into the coating film without bleeding or falling off, thereby achieving long-term weather resistance.

[0036] Specific examples of hydroxybenzophenones having a (meth)acryloyloxy group include 2-hydroxy-4-(2-(meth)acryloxyethoxy)benzophenone, 2-hydroxy-4-(4-(meth)acryloxybutoxy)benzophenone, 2,2'-dihydroxy-4-(2-(meth)acryloxyethoxy)benzophenone, 2,4-dihydroxy-4'-(2-(meth)acryloxyethoxy)benzophenone, 2,2',4-trihydroxy-4'-(2-(meth)acryloxyethoxy)benzophenone, 2-hydroxy-4-(3-(meth)acryloxy-2-hydroxypropoxy)benzophenone, and 2-hydroxy-4-(3-(meth)acryloxy-1-hydroxypropoxy)benzophenone.

[0037] Specific examples of hydroxybenzotriazoles having a (meth)acryloyloxy group include 2-(2'-hydroxy-5'-(meth)acryloxyphenyl)-2H-benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-(meth)acryloxymethylphenyl)-2H-benzotriazole, 2-[2'-hydroxy-5'-(2-(meth)acryloxyethyl)phenyl]-2H-benzotriazole, 2-[2'-hydroxy-3'-tert-butyl-5'-(2-(meth)acryloxyethyl)phenyl]-5-chloro-2H-benzotriazole, and 2-[2'-hydroxy-3'-methyl-5'-(8-(meth)acryloxyoctyl)phenyl]-2H-benzotriazole.

[0038] Specific examples of hydroxyphenyltriazines having a (meth)acryloyloxy group include a reaction product of 2-[4-[(2-hydroxy-3-(2'-ethyl)hexyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine) with 2-acryloyloxyethyl isocyanate (for example, Synthesis Example 1 in Japanese Patent No. 6354665), a reaction product of 2-[4-[(2-hydroxy-3-(2'-ethyl)hexyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine) with 1,1-bis(acryloyloxyethyl) Examples of such an acryloyloxymethyl methyl isocyanate include a reaction product of 2-[4-{(hydroxy-3-dodecyloxypropyl)oxy}-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine with 2-acryloyloxyethyl isocyanate (for example, Synthesis Example 1 of Japanese Patent No. 6156214), a reaction product of 2-[4-{(hydroxy-3-dodecyloxypropyl)oxy}-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine with 1,1-bis(acryloyloxymethyl)ethyl isocyanate. Two or more of these ultraviolet absorbents may be used in combination.

[0039] From the viewpoints of weather resistance and coating film appearance, the content of component (B) is preferably 10 to 30 mass %, more preferably 15 to 20 mass %, based on the nonvolatile content of the entire composition.

[0040] [3](C) component The photopolymerization initiator (C) may be appropriately selected from the viewpoints of compatibility and curability in the coating composition. Specific examples include carbonyl compounds such as benzoin, benzoin monomethyl ether, benzoin isopropyl ether, acetoin, benzil, benzophenone, p-methoxybenzophenone, diethoxyacetophenone, benzil dimethyl ketal, 2,2-diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, methylphenyl glyoxylate, and 2-hydroxy-2-methyl-1-phenylpropan-1-one; tetramethyl Examples of suitable compounds include sulfur compounds such as thiuram monosulfide and tetramethylthiuram disulfide; phosphoric acid compounds such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide; and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone-1 and camphorquinone. These compounds may be used alone or in combination of two or more, and can be combined as desired depending on the required coating film performance.

[0041] The content of component (C) is preferably 0.1 to 10 mass %, more preferably 1 to 8 mass %, based on the total nonvolatile content in the composition, in order to moderate the curing rate of the resulting coating film, improve the scratch resistance and adhesion to the substrate of the cured coating film, and prevent coloration and a decrease in weather resistance.

[0042] [4](D) component The photocurable coating composition of the present invention may optionally contain one or more components selected from (D) organopolysiloxanes having (meth)acryloyl groups but no urethane bonds, and silica particles surface-modified with alkoxysilanes having (meth)acryloyl groups but no urethane bonds, in order to improve the transparency, scratch resistance, substrate adhesion, durability, etc. of the coating film.

[0043] An organopolysiloxane having a (meth)acryloyl group but no urethane bond can be obtained, for example, by (co)hydrolytic condensation of an alkoxysilane having a (meth)acryloyl group but no urethane bond, or a mixture with other silanes. In addition, silica particles surface-modified with an alkoxysilane having a (meth)acryloyl group but not a urethane bond can be obtained by a method of (co)hydrolytic condensation of an alkoxysilane having a (meth)acryloyl group but not a urethane bond, or a mixture with other silanes, in the presence of colloidal silica, or by a method of dry-treating silica powder with such an alkoxysilane.

[0044] Specific examples of alkoxysilanes having a (meth)acryloyl group but no urethane bond include 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, 2-(meth)acryloxyethyltrimethoxysilane, 2-(meth)acryloxyethyltriethoxysilane, (meth)acryloxymethyltrimethoxysilane, (meth)acryloxymethyltriethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 8-(meth)acryloxyoctyltrimethoxysilane, and 8-(meth)acryloxyoctyltriethoxysilane.

[0045] As component (D), in consideration of obtaining a coating film that has excellent compatibility with other components, heat resistance, chemical resistance, durability, and adhesion to the substrate, 3-(meth)acryloxypropyltrimethoxysilane alone or its (co)hydrolysis condensation product with other silanes, or a product obtained by (co)hydrolysis condensation of 3-(meth)acryloxypropyltrimethoxysilane alone or with other silanes in the presence of colloidal silica, are suitable. These may be used alone or in combination of two or more, and can be combined as desired depending on the required coating film performance.

[0046] When component (D) is used, the blending amount is preferably 10 to 50 mass %, more preferably 20 to 40 mass %, of the total nonvolatile content in the composition, taking into consideration the transparency, scratch resistance, substrate adhesion, durability, etc. of the coating film.

[0047] [5](E) component The photocurable coating composition of the present invention may optionally contain (E) a silicon-free (meth)acrylate compound other than the above components (A), (B), and (D) in order to improve the transparency, scratch resistance, substrate adhesion, durability, etc. of the coating film. Examples of such (meth)acrylate compounds include one or more (meth)acrylates selected from monofunctional (meth)acrylates or polyfunctional (meth)acrylates, urethane (meth)acrylates, epoxy (meth)acrylates, polyester (meth)acrylates, etc. Among these, monofunctional and polyfunctional (meth)acrylates and urethane (meth)acrylates are preferred from the viewpoints of productivity and durability.

[0048] Specific examples of monofunctional (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, t-butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, morpholyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, glycidyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, and dimethicone. mono(meth)acrylates such as ethylaminoethyl (meth)acrylate, tricyclodecane (meth)acrylate, polyethylene glycol mono(meth)acrylate, cyclohexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, isobornyl (meth)acrylate, allyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, and phenyl (meth)acrylate; and mono(meth)acrylate compounds such as an adduct of phthalic anhydride and 2-hydroxyethyl (meth)acrylate.

[0049] Specific examples of polyfunctional (meth)acrylates include neopentyl glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, polyethylene glycol (number of repeating units (hereinafter referred to as "k") = 2 to 15) di(meth)acrylate, polypropylene glycol (k = 2 to 15) di(meth)acrylate, polybutylene glycol (k = 2 to 15) di(meth)acrylate, 2,2-bis(4-(meth)acryloxyethoxyphenyl)propane, 2,2-bis(4-(meth)acryloxydiethoxyphenyl)propane, trimethylolpropane diacrylate, bis(2-(meth)acryloxyethoxyphenyl)propane, )acryloxyethyl)-hydroxyethyl-isocyanurate, trimethylolpropane tri(meth)acrylate, tris(2-(meth)acryloxyethyl)isocyanurate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, epoxy poly(meth)acrylates such as epoxy di(meth)acrylates obtained by reacting bisphenol A diepoxy with (meth)acrylic acid, 1,Urethane tri(meth)acrylate obtained by reacting 2-hydroxyethyl (meth)acrylate with a trimer of 6-hexamethylene diisocyanate, urethane di(meth)acrylate obtained by reacting isophorone diisocyanate with 2-hydroxypropyl (meth)acrylate, urethane hexa(meth)acrylate obtained by reacting isophorone diisocyanate with pentaerythritol tri(meth)acrylate, urethane di(meth)acrylate obtained by reacting dicyclomethane diisocyanate with 2-hydroxyethyl (meth)acrylate, dicyclo Examples of such poly(meth)acrylates include urethane di(meth)acrylates obtained by reacting a urethane reaction product of methane diisocyanate and poly(k=6-15)tetramethylene glycol with 2-hydroxyethyl (meth)acrylate, polyester (meth)acrylates obtained by reacting trimethylolethane with succinic acid and (meth)acrylic acid, and polyester poly(meth)acrylates obtained by reacting trimethylolpropane with succinic acid, ethylene glycol, and (meth)acrylic acid.

[0050] Furthermore, other additives may be added to the photocurable coating composition of the present invention as long as the effects of the present invention are not impaired. Examples of such additives include antifouling agents, water repellents, leveling agents, colorants, pigments, antioxidants, anti-yellowing agents, bluing agents, defoamers, thickeners, anti-settling agents, antistatic agents, surfactants, adhesion promoters, infrared absorbers, light stabilizers, flexibility-imparting agents, curing catalysts, and metal oxide particles.

[0051] Furthermore, the photocurable coating composition of the present invention may contain an organic solvent, and the organic solvent is preferably selected and used depending on the coating method. For example, when used for spray coating, it is preferable to use any combination of alcohol solvents such as isobutanol, glycol solvents such as propylene glycol monomethyl ether, ester solvents such as n-butyl acetate, ketone solvents such as methyl isobutyl ketone, and aromatic solvents such as toluene, to achieve a viscosity of 20 mPa·s or less.When used for application by shower flow coating or dip coating, it is preferable to achieve a viscosity of 100 mPa·s or less. In the case of a high-solid coating composition having a solid content of more than 80% by mass, the solvent can be appropriately selected in consideration of the solubility of various additives.

[0052] The photocurable coating composition of the present invention can be applied to various substrates and cured to produce a cured coating film. During photocuring, the coating composition is applied to a substrate to form a specified film thickness, and then, after volatilizing the solvent as necessary, the coating is irradiated with ultraviolet light, electron beams, etc. using a high-pressure mercury lamp, metal halide lamp, LED lamp, etc. The irradiation atmosphere may be air or an inert gas such as nitrogen or argon.

[0053] Examples of substrates include organic resins such as plastic molded bodies, wood-based products, fibers, ceramics, glass, metals, and composites thereof, and the coating composition of the present invention can be suitably used for various plastic materials, although it is not particularly limited thereto. In particular, it can be suitably used for polycarbonate resin, polystyrene resin, acrylic resin, modified acrylic resin, urethane resin, thiourethane resin, polycondensation product of halogenated bisphenol A and ethylene glycol, acrylic urethane resin, halogenated aryl group-containing acrylic resin, sulfur-containing resin, polyalkylene terephthalate resin, cellulose resin, amorphous polyolefin resin, and composite resins thereof.

[0054] Furthermore, it is also possible to use resin substrates whose surfaces have been treated, specifically, those that have been subjected to chemical conversion treatment, corona discharge treatment, flame treatment, plasma treatment, or acid or alkaline solution treatment, and it is also possible to use laminates whose surface layer is coated with a type of resin different from that of the substrate body. Specific examples of the laminate include a laminate produced by coextrusion or lamination in which an acrylic resin layer or a urethane resin layer is present on the surface layer of a polycarbonate resin substrate, and a laminate in which an acrylic resin layer is present on the surface layer of a polyester resin substrate. The coating composition may be applied directly to the surface of the substrate, or may be applied via a primer layer, ultraviolet absorbing layer, printing layer, recording layer, heat ray shielding layer, adhesive layer, inorganic vapor deposition film layer, etc., as required.

[0055] The coating method can be appropriately selected from known coating methods such as a spin coater, comma coater, lip coater, roll coater, die coater, knife coater, blade coater, rod coater, kiss coater, gravure coater, screen coating, dip coating, and cast coating.

[0056] There are no particular restrictions on the thickness of the coating film produced from the photocurable coating composition of the present invention, but in order to prevent coating film defects, exhibit sufficient scratch resistance, and prevent cracking, a thickness of 0.1 to 50 μm is preferred, and in order to favorably exhibit the properties of hardness, scratch resistance, long-term stable adhesion, and resistance to cracking, a thickness of 1 to 30 μm is even more preferred.

[0057] Furthermore, if necessary, other coating layers such as an adhesive layer, an ultraviolet absorbing layer, a printing layer, a recording layer, a heat ray shielding layer, a pressure-sensitive adhesive layer, an inorganic vapor deposition film layer, a water- and oil-repellent layer, or a hydrophilic antifouling layer may be formed on the surface of the cured coating film of the photocurable coating composition of the present invention.

[0058] As described above, the cured coating film obtained from the photocurable coating composition of the present invention has excellent scratch resistance. To obtain even greater scratch resistance, an inorganic vapor deposition film layer may be coated on the coating film. The inorganic vapor deposition film layer is not particularly limited as long as it is formed by a dry film formation method, and examples thereof include layers whose main component is at least one of various metals containing elements such as Si, Ti, Zn, Al, Ga, In, Ce, Bi, Sb, B, Zr, Sn, and Ta, or oxides, nitrides, and sulfides of these metals. Further examples thereof include diamond-like carbon film layers, which have high hardness and excellent insulating properties. The method for laminating the inorganic vapor deposition film layer is not particularly limited as long as it is a dry film formation method, and examples thereof include physical vapor deposition methods such as resistance heating vapor deposition, electron beam vapor deposition, molecular beam epitaxy, ion beam deposition, ion plating, and sputtering, and chemical vapor deposition methods such as thermal CVD, plasma CVD, photo CVD, epitaxial CVD, atomic layer CVD, and catCVD.

[0059] An article coated with the cured product of the coating composition of the present invention thus obtained can have excellent scratch resistance and weather resistance, particularly weather crack resistance.

[0060] The photocurable coating composition of the present invention is preferably used as a photocurable coating composition for articles to be used outdoors. In particular, it is preferable to use it for surface coating of automobile headlamp lenses, vehicle sensor covers, and resin glass.The substrate for these is polycarbonate, which is commonly used because it has high impact resistance, heat resistance, transparency, and lightness.However, polycarbonate is lacking in performance such as chemical resistance, weather resistance, and scratch resistance, so it is preferable to coat the surface with the coating composition of the present invention to improve these performances.

[0061] Furthermore, polycarbonates coated with a coating film made from the photocurable coating composition of the present invention can prevent yellowing and weather-resistant cracking of the coating film, and furthermore, exhibit excellent water repellency and stain resistance, and are lightweight and easily moldable, so they can be used in a wide variety of applications, such as automobile headlamp lenses, vehicle sensors, vehicle windows, outdoor signs, window glass for greenhouses and outdoor buildings, terrace and garage roofs, balconies, and instrument covers. [Example]

[0062] The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the following examples, unless otherwise specified, "parts" and "%" mean "parts by mass" and "% by mass", respectively. The devices used in the examples are as follows.

[0063] (1) GPC measurement conditions Apparatus: Tosoh Corporation HLC-8320GPC Column: Tosoh Corporation TSKgel G4000HXL + G3000HXL + G2000HXL + G2000HXL (inner diameter 6 mm, length 150 mm) Developing solution: tetrahydrofuran Column tank temperature: 40℃ Flow rate: 1mL / min Detector: Refractive Index (RI) Standard: Monodisperse polystyrene (2) Proton nuclear magnetic resonance spectrum ( 1 H-NMR) measurement conditions Equipment: BRUKER AVANCE III 400 Solvent: CDCl3 Internal standard: tetramethylsilane (TMS) (3) Infrared absorption spectrum (IR) measurement conditions Apparatus: Thermo Fisher Nicolet 6700

[0064] [1] Synthesis of organopolysiloxane [Synthesis Example 1] A 500 mL brown glass reactor equipped with a stirrer, thermometer, reflux condenser, and dropping funnel was charged with 96.7 g of a dimethylpolysiloxane (KF-6001, manufactured by Shin-Etsu Chemical Co., Ltd., hydroxyl value 58 mgKOH / g, formula (13) below) modified with both ends of carbinol, 48.4 g of butyl acetate, 0.03 g of t-butylhydroxytoluene as a polymerization inhibitor, and 0.03 g of dioctyltin oxide as a urethanization catalyst. The mixture was heated and stirred until the internal temperature reached 70°C. 50.2 g of 1,1-(bisacryloyloxymethyl)ethyl isocyanate (Karends BEI, manufactured by Showa Denko K.K., molecular weight 239) was added dropwise over 1.5 hours with heating. The mixture was then reacted at 80°C for 3 hours, followed by the addition of 10 g of methanol to deactivate the remaining isocyanate groups, and the mixture was reacted at 70°C for 1 hour. After cooling to 25 °C, IR measurement revealed an absorption peak (2,260 cm) derived from NCO. -1 ) had almost completely disappeared, confirming the consumption of the raw material Karenz BEI. Next, the low molecular weight components were concentrated under reduced pressure and filtered through a nylon mesh (100 mesh), yielding 156.8 g of pale yellow, transparent organopolysiloxane A-1. This had a kinematic viscosity of 10,400 mPa·s and a non-volatile content of 98.6%. GPC and 29 The structure of A-1 confirmed by Si-NMR and IR measurements is shown in the following formula (14).

[0065] [ka]

[0066] [ka]

[0067] [Synthesis Example 2] A 500 mL brown glass reactor equipped with a stirrer, thermometer, reflux condenser, and dropping funnel was charged with 48.8 g of a dimethylpolysiloxane modified at both ends with carbinol (KF-6000, manufactured by Shin-Etsu Chemical Co., Ltd., hydroxyl value 115 mgKOH / g, formula (15) below), 48.8 g of butyl acetate, 0.03 g of t-butylhydroxytoluene as a polymerization inhibitor, and 0.03 g of dioctyltin oxide as a urethanization catalyst, and the mixture was heated and stirred until the internal temperature reached 60°C. 22.2 g of isophorone diisocyanate (Desmodur I, manufactured by Covestro, molecular weight 222) was added dropwise over 1 hour with heating. The mixture was then allowed to react for 3 hours at 60°C, after which 80.7 g of a mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate (MIRAMER M340, manufactured by MIWON, 57% / 43% mixture, hydroxyl value 139 mgKOH / g) was added, the temperature was raised to 80°C, and the mixture was stirred for 3 hours. 10 g of methanol was added to deactivate any remaining isocyanate groups, and the mixture was allowed to react for 1 hour at 80°C. After cooling to 25°C, the low molecular weight components were concentrated under reduced pressure and filtered through a nylon mesh (100 mesh), yielding 147.6 g of a pale yellow, transparent organopolysiloxane A-2. The kinematic viscosity of this product at 40°C was 37,100 mPa·s, and the nonvolatile content was 97.5%. Furthermore, GPC and 1 The structure of A-2 confirmed by H-NMR and IR measurements is shown in the following formula (16).

[0068] [ka]

[0069] [ka]

[0070] [Synthesis Example 3] A 1-L brown glass reactor equipped with a stirrer, thermometer, reflux condenser, and dropping funnel was charged with 155.8 g of a dimethylpolysiloxane modified at both ends with carbinol (KF-6002, manufactured by Shin-Etsu Chemical Co., Ltd., hydroxyl value 36 mgKOH / g, formula (17) below), 155.8 g of butyl acetate, 0.05 g of t-butylhydroxytoluene as a polymerization inhibitor, and 0.05 g of dioctyltin oxide as a urethanization catalyst, and the mixture was heated and stirred until the internal temperature reached 60°C. 22.2 g of isophorone diisocyanate (Desmodur I, manufactured by Covestro, molecular weight 222) was added dropwise over 1 hour while heating. The mixture was then allowed to react at 60°C for 3 hours, after which 224.4 g of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (A-9550, manufactured by Shin-Nakamura Chemical Co., Ltd., hydroxyl value 50 mgKOH / g) was added, and the mixture was heated to 80°C and stirred for 3 hours. 10 g of methanol was added to deactivate any remaining isocyanate groups, and the mixture was allowed to react at 80°C for 1 hour. After cooling to 25°C, the low molecular weight components were concentrated under reduced pressure and filtered through a nylon mesh (100 mesh), yielding 379.6 g of a pale yellow, transparent organopolysiloxane A-3. The kinematic viscosity of this product at 40°C was 68,400 mPa·s, and the nonvolatile content was 98.2%. Furthermore, GPC and 1 The structure of A-3 confirmed by H-NMR and IR measurements is shown in the following formula (18).

[0071] [ka]

[0072] [ka]

[0073] [Comparative Synthesis Example 1] A 500 mL brown glass reactor equipped with a stirrer, thermometer, reflux condenser, and dropping funnel was charged with 48.8 g of carbinol-end-modified dimethylpolysiloxane (Shin-Etsu Chemical Co., Ltd., KF-6000, hydroxyl value 115 mgKOH / g, formula (15) above), 48.8 g of butyl acetate, 0.03 g of t-butylhydroxytoluene as a polymerization inhibitor, and 0.03 g of dioctyltin oxide as a urethanization catalyst. The mixture was heated and stirred until the internal temperature reached 60°C. 22.2 g of isophorone diisocyanate (COVESTRONG, Desmodur I, molecular weight 222) was added dropwise over 1 hour with heating. The mixture was then allowed to react at 60°C for 3 hours, after which 23.2 g of 2-hydroxyethyl acrylate (Tokyo Chemical Industry Co., Ltd., molecular weight 116) was added. The mixture was heated to 80°C and stirred for 3 hours. To deactivate the remaining isocyanate groups, 10 g of methanol was added, and the mixture was allowed to react at 80°C for 1 hour. After cooling to 25°C, the low molecular weight components were concentrated under reduced pressure, and then filtered through a nylon mesh (100 mesh), yielding 90.8 g of pale yellow, transparent polysiloxane A-4. The kinematic viscosity of this product was 820 mPa·s, and the nonvolatile content was 98.1%. Furthermore, GPC and 1 The structure of A'-4 confirmed by H-NMR and IR measurements is shown in the following formula (19).

[0074] [ka]

[0075] [Synthesis Example 4] Synthesis of organopolysiloxane D-1 having (meth)acryloyl groups but no urethane bonds 142 g of acryloyloxypropyltrimethoxysilane (KBM5103, manufactured by Shin-Etsu Chemical Co., Ltd.), 500 g of isopropyl alcohol, 0.1 g of p-methoxyphenol, 1.0 g of tetramethylammonium hydroxide, and 20 g of deionized water were combined and reacted at 20°C for 24 hours to obtain a colorless, transparent liquid. The mixture was concentrated by distillation under reduced pressure to obtain organopolysiloxane D-1, a colorless, transparent liquid.

[0076] [Synthesis Example 5] A mixture of 2.8 g of acryloyloxypropyltrimethoxysilane (KBM5103, manufactured by Shin-Etsu Chemical Co., Ltd.), 95.6 g of methyl ethyl ketone-dispersed silica sol (MEK-ST, manufactured by Nissan Chemical Industries, Ltd., number average particle size 45 nm, silica concentration 30%), and 0.1 g of ion-exchanged water was stirred at 80°C for 3 hours, after which 1.4 g of trimethyl orthoformate was added and the mixture was heated and stirred for an additional hour at the same temperature to obtain a dispersion of surface-treated silica particles D-3. The solids content of the resulting dispersion was 32% by mass, and the average particle size of the surface-treated silica particles D-3 was 45 nm.

[0077] [2] Preparation of coating composition and production of coated article [Examples 1-1 to 1-8, Comparative Examples 1-1 to 1-5] The following components (A) to (F) were mixed with stirring at 25°C in the amounts shown in Tables 1 and 2, and then filtered through a filter paper to prepare coating compositions (X1 to X8).

[0078] Component (A) A-1: Organopolysiloxane obtained in Synthesis Example 1 A-2: Organopolysiloxane obtained in Synthesis Example 2 A-3: Organopolysiloxane obtained in Synthesis Example 3 A'-4 (comparative component): organopolysiloxane obtained in Comparative Synthesis Example 1

[0079] (B) Component B-1: 2-[4-[(2-hydroxy-3-(2'-ethyl)hexyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine (manufactured by BASF, Tinuvin 405) B-2: A compound represented by the following structural formula (20), obtained by the method described in Synthesis Example 1 of Japanese Patent No. 6354665. [ka]

[0080] (C) Component C-1: 2,4,6-trimethylbenzoyldiphenylphosphine oxide (BASF) C-2: 1-Hydroxycyclohexylphenyl ketone (BASF, Irgacure 184)

[0081] (D) Component D-1: Acryloyl group-containing organopolysiloxane obtained in Synthesis Example 4 D-2: Acryloyl group-containing organopolysiloxane (KR-513, manufactured by Shin-Etsu Chemical Co., Ltd.) D-3: Surface-treated silica particles obtained in Synthesis Example 5 (32% by mass dispersion in methyl ethyl ketone)

[0082] (E) Component E-1: Dipentaerythritol hexaacrylate (MIWON, MIRAMER M600) E-2: 1,6-hexanediol diacrylate (A-HD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.)

[0083] (F) Additives F-1: Polyether silicone leveling agent (Shin-Etsu Chemical Co., Ltd., Leveling Agent A) F-2: An acrylate compound having a perfluoropolyether group represented by the following formula (21), obtained by the method described in Example 1 of Japanese Patent No. 4873666:

[0084] [ka] Rf:-CF2(OCF2CF2) p (OCF2) q OCF2-(p / q=0.9, p+q≒45) F-3: An organopolysiloxane represented by the following formula (22), obtained by the method described in Synthesis Example 1 of International Publication WO2022 / 065019 [ka] (In the formula, Me represents a methyl group, and Bu represents an n-butyl group.)

[0085] (G) Solvent G-1: Propylene glycol monomethyl ether (PGM)

[0086] [Table 1]

[0087] [Table 2]

[0088] [Examples 2-1 to 2-8, Comparative Examples 2-1 to 2-5] The coating compositions obtained in the above Examples and Comparative Examples were applied to the surface of a polycarbonate NF-2000 sheet (2 mm thick × 15 cm long × 10 cm wide) manufactured by Mitsubishi Engineering Plastics Corporation by flow coating, then air-dried for 5 minutes, heated at 80°C for 1 minute, and then irradiated with 600 mJ / cm using a high-pressure mercury lamp. 2 The coating film was cured by irradiating it with light at an irradiation dose of 1000 kJ / cm 2 , and the obtained test pieces were evaluated as follows. The results are shown in Tables 3 and 4. (1) Coating appearance The coating film was visually inspected to determine whether or not there was any abnormality. ○: No abnormalities △: Colored ×: Abnormalities such as foreign matter, unevenness, cracks, and peeling are present (2) Hayes The haze of the coated sheet was measured using a haze meter NDH5000SP manufactured by Nippon Denshoku Industries Co., Ltd. (3)SW resistance Using a Gakushin-type abrasion tester AB-301 manufactured by Tester Sangyo Co., Ltd., steel wool No. 0000 was attached and the haze value was measured after 11 round trips with a load of 500 g. The difference in haze value before and after the test was taken as the abrasion resistance. A difference in haze value of 7 or less was considered to be pass. (4) Water contact angle A 2 μL droplet of pure water was brought into contact with the coating film and the contact angle was measured using a fully automatic contact angle meter DM-701 manufactured by Kyowa Interface Science Co., Ltd. A contact angle of 95° or more was considered to be acceptable. (5) Easy to wipe off with a marker A line of approximately 2 cm was written on the coating using Zebra Corporation's Hi-Mackey (registered trademark) black, and then wiped twice with Nippon Paper Crecia Co., Ltd.'s Kaydry (registered trademark). The appearance was then visually observed and judged according to the following criteria. ○: No marks left behind and can be wiped off cleanly △: Mostly wiped off, but traces are visible ×: Almost no wiping (6) Weather resistance evaluation The test was performed using Iwasaki Electric Co., Ltd.'s Eye Super UV Tester W-151, with the black panel temperature set at 63°C, humidity at 50% RH, and illuminance at 50 mW / cm. 2 The test was carried out for 300 hours under the following conditions: [5 hours of rain, 10 seconds per hour] → [1 hour at a black panel temperature of 30°C and a humidity of 95% RH]. After the weather resistance test, the coating was evaluated for its appearance, haze, water contact angle, and wipeability with a marker.

[0089] [Table 3]

[0090] [Table 4]

[0091] The coatings obtained from the coating compositions of Examples 1-1 to 1-8 (X1 to X8) had a high water contact angle of 95° or more after a weather resistance test and were also excellent in wipeability with a marker. In particular, the coatings of Examples 1-2 to 1-8 (X2 to X8), which used a UV absorber having an acryloyl group, did not discolor after the weather resistance test and had excellent appearance. This result is presumably due to the suppression of bleeding of the UV absorber. On the other hand, the coatings made from the compositions of Comparative Example 1-1 (R1), which did not contain the organopolysiloxane component (A), and Comparative Examples 1-4 and 1-5 (R4, R5), which contained less than 30 mass% of the component (A) calculated as non-volatile content in the composition, exhibited poor water contact angles and ease of wiping with a marker, and cracks were observed in the coatings after the weather resistance test (R1, R4). The coating film made from the composition of Comparative Example 2-1 (R2), in which the organopolysiloxane (A) was changed to one in which a = 1, had uneven coating appearance and poor scratch resistance.Furthermore, after the weather resistance test, the water contact angle and the wipeability with a marker were reduced. The coating made of the composition of Comparative Example 3 (R3), which did not contain the ultraviolet absorber of component (B), yellowed after the weather resistance test, and also partially peeled off.

Claims

1. (A) an organopolysiloxane represented by the following formula (1): 【Chemistry 1】 [In the formula, R 1 each independently represents a hydrogen atom or a monovalent hydrocarbon group optionally interrupted by an oxygen atom, X's each independently represent a divalent saturated hydrocarbon group having 2 to 30 carbon atoms which may be interrupted by an oxygen atom; Q are each independently a group represented by any one of the following formulas (3) to (12): 【Chemistry 2】 (In formulas (3) to (12), *5 is bonded to P in formula (1), and *6 is bonded to the nitrogen atom in the urethane group in formula (1).) P's each independently represent an acryloyloxy group or a methacryloyloxy group, a's each independently represent an integer from 2 to 5; n represents an integer of 0 to 100. (B) an ultraviolet absorber, and (C) Photopolymerization initiator wherein the content of component (A) calculated as nonvolatile content is 30 to 99 mass %.

2. The R 1 2. The photocurable coating composition of claim 1, wherein is a methyl group.

3. 2. The photocurable coating composition according to claim 1, wherein each X is independently an oxyalkylene group having 2 to 20 carbon atoms.

4. 4. The photocurable coating composition according to claim 3, wherein X is a group represented by the following formula (2): 【Transformation 3】 (In the formula, * 1 is bonded to the silicon atom of the formula (1), * 2 is bonded to the oxygen atom in the urethane group of the formula (1).

5. 2. The photocurable coating composition according to claim 1, wherein each Q is independently a group represented by any one of the following formulas (3), (10), (11) and (12): 【Chemistry 4】 (wherein *5 is bonded to P in formula (1), and *6 is bonded to the nitrogen atom in the urethane group in formula (1).)

6. 2. The photocurable coating composition according to claim 1, wherein n is an integer of 1 to 80.

7. 2. The photocurable coating composition according to claim 1, wherein the component (B) is an ultraviolet absorber having a (meth)acryloyl group.

8. 2. The photocurable coating composition according to claim 1, comprising (D) at least one selected from the group consisting of an organopolysiloxane having a (meth)acryloyl group but not a urethane bond, and silica particles surface-modified with an alkoxysilane having a (meth)acryloyl group but not a urethane bond.

9. 2. The photocurable coating composition according to claim 1, further comprising (E) a (meth)acrylate compound having no silicon atom (excluding component (B)).

10. A cured film of the photocurable coating composition according to any one of claims 1 to 9.

11. A coated article comprising a substrate and a cured film of the photocurable coating composition of claim 10 formed on the substrate directly or via at least one other layer.

12. 12. The coated article according to claim 11, wherein the substrate is an organic resin or wood.

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