Coating composition, method for producing the same and coated article

Abstract

To provide a coating composition which can be easily produced and gives a cured film having excellent chemical resistance or the like.SOLUTION: There is provided a coating composition which comprises (A) a polyol such as an acrylic polyol, (B) a compound having two or more isocyanate groups in one molecule, and (C) 5 to 500 pts.mass of a hydroxyl group-containing organopolysiloxane represented by the following formula (I) based on 100 pts.mass of the component (A) (R1 is a monovalent saturated hydrocarbon group or the like, R2 is a methyl group or the like, R3 is a group represented by the following formula (II).) (R4 is a monovalent saturated hydrocarbon group or the like, R5 is a hydrogen atom or the like, X is a divalent hydrocarbon group, n is a number of 0 to 400, and * represents a bond to an oxygen atom.), wherein the ratio of the number of isocyanate groups in the component (B) to the sum of the number of hydroxyl groups in the components (A) and (C) is 0.8 to 1.4.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a coating composition, a method for producing the same, and a coated article, and more specifically to a coating composition containing an organic resin and an organopolysiloxane, a method for producing the coating composition, and a coated article having a cured film made of the coating composition. [Background technology]

[0002] Organopolysiloxanes containing alkoxysilyl groups are widely used in paints and coatings. In general, organopolysiloxanes having alkoxy groups at the terminals are mixed with a curing catalyst, and when external energy such as heat energy is applied, the alkoxy groups at the terminals react with each other to form a strong siloxane network. As a result, the resulting coating has excellent heat resistance and weather resistance, so it can be applied to a wide range of objects, from outdoor structures to automobile parts and electronic parts.

[0003] On the other hand, while organopolysiloxane-based paints have the above-mentioned advantages, they also have the disadvantages of a slow curing rate and the resulting coating films having poor crack resistance and bending resistance.

[0004] In order to overcome these drawbacks, a method has been known in the past in which a composition obtained by mixing an organopolysiloxane with an organic resin such as an alkyd resin, a polyester resin, an acrylic resin, or an epoxy resin is used as a coating material. As such a composition, Patent Document 1 proposes, for example, a coating material composition containing a silyl group-containing vinyl polymer, a silanol group-containing organopolysiloxane, and an alkoxy group-containing organopolysiloxane. However, although this composition improves the curability and crack resistance, it has the problem that the characteristics of organopolysiloxane resin coating films, such as chemical resistance, stain resistance, and weather resistance, are reduced.

[0005] In addition, Patent Documents 2 to 5 propose a method of reacting an organic resin with an organosilane or an organopolysiloxane to form a composite. However, this method requires synthesis equipment for forming a composite of the resin, and therefore has a problem in terms of versatility. For this reason, there is a demand for a simple method for bringing out the best properties of both organopolysiloxane and organic resin. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 3-197548 [Patent Document 2] Japanese Patent Application Publication No. 11-116683 [Patent Document 3] Japanese Patent Application Publication No. 5-345877 [Patent Document 4] Patent No. 5384939 [Patent Document 5] Patent No. 6113456 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a coating composition containing an organic resin and an organopolysiloxane, which can be easily produced and gives a cured coating film having excellent chemical resistance, antifouling properties, and weather resistance. [Means for solving the problem]

[0008] Means for Solving the Problems The present inventors have conducted extensive research in order to achieve the above object and have discovered that a coating composition comprising a polyol, a polyisocyanate and a specific hydroxyl-containing organopolysiloxane in specific proportions can be cured at room temperature and that a coating film obtained from said composition satisfies the required chemical resistance, antifouling properties and weather resistance, thereby completing the present invention.

[0009] That is, the present invention provides 1. (A) One or more polyols selected from the group consisting of acrylic polyol, polyester polyol, and polyether polyol, (B) A compound having two or more isocyanate groups in one molecule, and (C) A hydroxyl group-containing organopolysiloxane represented by the following formula (I): 5 to 500 parts by mass based on 100 parts by mass of the component (A) [Chemical formula] (In the formula, R 1 is each independently a hydrogen atom or a monovalent saturated hydrocarbon group having 1 to 12 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or an aryl group having 6 to 18 carbon atoms, which may be substituted with a halogen atom, R 2 is a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, or an i-propyl group, R 3 is a group represented by the following formula (II), and a, b, c, and d are numbers satisfying 0 ≦ a < 1, 0 < b ≦ 1, 0 ≦ c ≦ 0.5, 0 ≦ d < 1, and a + b + c + d = 1, respectively, and e and f are numbers satisfying 0 ≦ e ≦ 1, 0 < f < 4, and 0 < e + f < 4, respectively.) [Chemical formula] (In the formula, R 4 is each independently a hydrogen atom or a monovalent saturated hydrocarbon group having 1 to 12 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or an aryl group having 6 to 18 carbon atoms, which may be substituted with a halogen atom, R 5 is each independently a hydrogen atom or a monovalent saturated hydrocarbon group having 1 to 8 carbon atoms, X is a divalent hydrocarbon group having 2 to 8 carbon atoms, n is a number from 0 to 400, and * represents a bond with an oxygen atom.) comprising, The ratio (NCO (B) / OH (A+C) ) of the number of isocyanate groups in the component (B) to the sum of the number of hydroxyl groups in the component (A) and the number of hydroxyl groups in the component (C) is 0.8 to 1.4, a paint composition, 2. The coating composition according to 1, wherein the component (A) is an acrylic polyol, a polyester polyol, or both of these. 3. The coating composition according to 1, wherein the component (B) is a polyisocyanate having two or more isocyanate groups in one molecule and having no silicon atoms. 4. In the above formula (I), R 1 2. The coating composition according to 1, wherein at least one of the groups is an aryl group having 6 to 18 carbon atoms. 5. In the above formula (I), R 1 each independently represents a methyl group or a phenyl group; 6. In the above formula (I), R 2 is a methyl group; 7. The coating composition according to 1, wherein in formula (I), b is a number satisfying 0.5≦b≦1. 8. The coating composition according to 1, wherein in formula (I), a and d are 0. 9. In the above formula (II), R 4 is a methyl group, and R 5 is a hydrogen atom, X is an alkylene group having 3 carbon atoms, and n is 1; 10. The coating composition according to 1, wherein the weight average molecular weight (Mw) of the component (C) in terms of polystyrene measured by gel permeation chromatography is 1,000 to 500,000. 11. The coating composition according to 1, further comprising (D) a curing catalyst. 12. The method for producing a coating composition according to any one of 1 to 11, wherein the components (A) to (C) are mixed at 10 to 40° C. 13. A cured film formed from the coating composition according to any one of 1 to 11. 14. A coated article having a substrate and the cured film according to 13 formed on at least one surface of the substrate directly or via one or more other layers. to provide. Effect of the Invention

[0010] The coating composition of the present invention can be produced simply by mixing a polyol, a polyisocyanate, and a hydroxyl-containing organosiloxane, and gives a cured film that has excellent chemical resistance, antifouling properties, and weather resistance, making it suitable for producing a variety of coated articles. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present invention will be specifically described below. The coating composition of the present invention contains the following components (A) to (C): (A) Polyol (B) Polyisocyanate (C) A hydroxyl-containing organopolysiloxane having a structure represented by the following average formula (I): [ka]

[0012] (1)(A) Polyol The polyol of component (A) has two or more reactive hydroxyl groups in one molecule and reacts with component (B) having an isocyanate group in the presence or absence of a curing catalyst to form a crosslinked structure.

[0013] Examples of polyols include acrylic polyols, which are (co)polymers of a (meth)acrylic monomer having a hydroxyl group and any other (meth)acrylic monomer, etc.; polyester polyols, which are condensation polymers of polybasic acids and polyhydric alcohols (including alkyd polyols, which are condensation polymers of polybasic acids and fatty acids and polyhydric alcohols); and polyether polyols, which are addition polymers of polyhydric alcohols and alkylene oxides. Among these, acrylic polyols and polyester polyols are preferred, and acrylic polyols are particularly preferred because the resulting coating film is excellent in transparency and gloss. In this specification, the term "(meth)acrylic monomer" includes both acrylic monomers and methacrylic monomers.

[0014] Specific examples of (meth)acrylic monomers having a hydroxyl group, which are raw material monomers for acrylic polyols, include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, di-2-hydroxyethyl fumarate, mono-2-hydroxyethyl monobutyl fumarate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, and "PLACCEL FM or PLACCEL FA" [caprolactone addition monomer manufactured by Daicel Chemical Industries, Ltd.] and other hydroxyalkyl esters of various α,β-ethylenically unsaturated carboxylic acids, or adducts of these with ε-caprolactone. Among these, 2-hydroxyethyl (meth)acrylate is preferred because it reacts easily.

[0015] The other (meth)acrylic monomer that can be copolymerized with the (meth)acrylic monomer having a hydroxyl group is not particularly limited, and any known monomer can be used. Also, vinyl monomers can be copolymerized. For example, alkyl (meth)acrylates having an alkyl group having 1 to 22 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and lauryl (meth)acrylate; aralkyl (meth)acrylates, such as benzyl (meth)acrylate and 2-phenylethyl (meth)acrylate; cycloalkyl (meth)acrylates, such as cyclohexyl (meth)acrylate and isobornyl (meth)acrylate; ω-alkoxyalkyl (meth)acrylates, such as 2-methoxyethyl (meth)acrylate and 4-methoxybutyl (meth)acrylate; aromatic vinyl monomers, such as styrene, p-tert-butylstyrene, α-methylstyrene, and vinyltoluene; and acetic acid. Examples of the vinyl esters include vinyl carboxylates such as vinyl, vinyl propionate, vinyl pivalate, and vinyl benzoate; alkyl esters of crotonic acid such as methyl crotonate and ethyl crotonate; dialkyl esters of unsaturated dibasic acids such as dimethyl maleate, di-n-butyl maleate, dimethyl fumarate, and dimethyl itaconate; α-olefins such as ethylene and propylene; fluoroolefins such as vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, and chlorotrifluoroethylene; alkyl vinyl ethers such as ethyl vinyl ether and n-butyl vinyl ether; cycloalkyl vinyl ethers such as cyclopentyl vinyl ether and cyclohexyl vinyl ether; and tertiary amide group-containing monomers such as N,N-dimethyl(meth)acrylamide, N-(meth)acryloylmorpholine, N-(meth)acryloylpyrrolidine, and N-vinylpyrrolidone.

[0016] The polymerization method, solvent, and polymerization initiator used when copolymerizing these monomers are not particularly limited. For example, polymerization can be carried out by various polymerization methods such as bulk radical polymerization, solution radical polymerization, and nonaqueous dispersion radical polymerization, using, as necessary, solvents such as hydrocarbons such as hexane, octane, toluene, and xylene, ketones such as methyl ethyl ketone, esters such as ethyl acetate, and alcohols such as isopropyl alcohol, and using polymerization initiators such as 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylbutyronitrile), tert-butyl peroxypivalate, tert-butyl peroxybenzoate, tert-butyl peroxy-2-ethylhexanoate, di-tert-butyl peroxide, cumene hydroperoxide, and diisopropyl peroxycarbonate.

[0017] The molecular weight of the polyol of component (A) is not particularly limited, but from the viewpoints of curability, weather resistance, and coatability, the weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography is preferably 1,000 to 100,000, and more preferably 2,000 to 80,000. The amount of hydroxyl groups contained in component (A) is not particularly limited, but the hydroxyl value is preferably from 10 to 200 mgKOH / g, and more preferably from 20 to 180 mgKOH / g. Note that in the present invention, the hydroxyl value is a value measured according to JIS K 1557-1:2007. The component (A) may use either a single type alone, or a combination of two or more types.

[0018] As the component (A), commercially available products can be used, such as ACRYDIC A-801P (acrylic polyol), BURNOCK D-220 (polyester polyol) (both manufactured by DIC Corporation), and DURANATE TPA-100 (manufactured by Asahi Kasei Corporation).

[0019] (2)(B) Polyisocyanate The component (B) is an isocyanate compound having two or more isocyanate groups in one molecule.

[0020] As the isocyanate compound, known compounds such as aromatic, aliphatic, araliphatic, and alicyclic polyisocyanates, and organosilicon compounds having an isocyanate group can be used. However, polyisocyanates not having silicon atoms are preferred, and from the viewpoint of long-term outdoor use, aliphatic polyisocyanates using an aliphatic diisocyanate as the main raw material are suitable. Examples of aliphatic diisocyanates include tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate (hereinafter abbreviated as "HDI"), 2,2,4-(or 2,4,4)-trimethyl-1,6-hexamethylene diisocyanate, lysine isocyanate, isophorone diisocyanate, hydrogenated xylene diisocyanate, hydrogenated diphenylmethane diisocyanate, 1,4-diisocyanate cyclohexane, 1,3-bis(diisocyanate methyl)cyclohexane, and 4,4'-dicyclohexylmethane diisocyanate. Among these, HDI is particularly suitable from the viewpoints of the crack resistance of the resulting coating film and cost.

[0021] Examples of the aliphatic polyisocyanate obtained from the aliphatic diisocyanate include allophanate type polyisocyanates, biuret type polyisocyanates, adduct type polyisocyanates, and isocyanurate type polyisocyanates, and any of these can be suitably used.

[0022] As the polyisocyanate, there can also be used so-called blocked polyisocyanate compounds which are blocked with various blocking agents. Examples of blocking agents that can be used include alcohols such as methanol, ethanol, and lactate esters; phenolic hydroxyl group-containing compounds such as phenol and salicylic acid esters; amides such as ε-caprolactam and 2-pyrrolidone; oximes such as acetone oxime and methyl ethyl ketoxime; and active methylene compounds such as methyl acetoacetate, ethyl acetoacetate, and acetylacetone.

[0023] The amount of isocyanate groups contained in the component (B) is not particularly limited, but the isocyanate content is preferably 5 to 50 mass%, more preferably 10 to 40 mass%. In the present invention, the isocyanate content is a value according to JIS K1603-1:2007.

[0024] As the component (B), commercially available products can be used, such as DN-901S and DN-990S (both manufactured by DIC Corporation).

[0025] The amount of component (B) blended is determined based on the ratio of the number of isocyanate groups in component (B) to the sum of the number of hydroxyl groups in component (A) and the number of hydroxyl groups in component (C) described below (NCO (B) / OH (A+C) ) is an amount such that the difference between the chemical resistance and weather resistance of the resulting cured film is 0.8 to 1.4, and preferably 0.9 to 1.2. If it is less than 0.8, the chemical resistance and weather resistance of the resulting cured film are poor, and if it exceeds 1.4, the stain resistance and weather resistance of the resulting cured film are poor. The component (B) may use either a single type alone, or a combination of two or more types.

[0026] (3)(C) Hydroxyl-containing organopolysiloxane Component (C) is a hydroxyl-containing organopolysiloxane represented by the following formula (I), and preferably has multiple hydroxyl groups in one molecule.

[0027] [ka]

[0028] In formula (I), R 1 each independently represents a hydrogen atom, or a monovalent saturated hydrocarbon group having 1 to 12 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or an aryl group having 6 to 18 carbon atoms, each of which may be substituted with a halogen atom.

[0029] R 1 The monovalent saturated hydrocarbon group having 1 to 12 carbon atoms may be linear, branched or cyclic, and specific examples thereof include linear or branched alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, i-butyl, tert-butyl, neopentyl, n-hexyl, n-heptyl, and n-octyl groups; and cycloalkyl groups such as cyclopentyl and cyclohexyl groups. Of these, alkyl groups having 1 to 6 carbon atoms are preferred, and alkyl groups having 1 to 3 carbon atoms are even more preferred, with methyl and ethyl groups being even more preferred. As the aralkyl group having 7 to 20 carbon atoms, those having 7 to 10 carbon atoms are preferable, and specific examples thereof include a benzyl group and a phenylethyl group. As the aryl group having 6 to 18 carbon atoms, those having 6 to 10 carbon atoms are preferable, and specific examples thereof include unsubstituted aryl groups such as phenyl and naphthyl groups; and alkylaryl groups such as tolyl, xylyl, ethylphenyl, propylphenyl, butylphenyl, pentylphenyl, hexylphenyl, heptylphenyl, octylphenyl, nonylphenyl, decylphenyl, undecylphenyl, and dodecylphenyl groups, with a phenyl group being preferable. Among these, R 1 is preferably a methyl group or a phenyl group. In addition, the monovalent saturated hydrocarbon group, aralkyl group and aryl group may have some or all of their hydrogen atoms substituted with halogen atoms (fluorine, chlorine, bromine, iodine atoms), and specific examples thereof include chloromethyl, chloropropyl, bromoethyl, trifluoropropyl, chlorophenyl, and bromophenyl groups. 1 At least one of these is preferably a halogen-substituted or unsubstituted aryl group having 6 to 18 carbon atoms.

[0030] R 2 represents a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, or an i-propyl group, preferably a methyl group, an ethyl group, an n-propyl group, or an i-propyl group, more preferably a methyl group or an ethyl group, and even more preferably a methyl group.

[0031] R 3 is a group represented by the following formula (II): [ka]

[0032] In formula (II), R 4 are each independently a hydrogen atom, or a monovalent saturated hydrocarbon group having 1 to 12 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or an aryl group having 6 to 18 carbon atoms, each of which may be substituted with a halogen atom. Specific examples of these monovalent saturated hydrocarbon groups, aralkyl groups, and aryl groups include the above-mentioned R 1 Among them, R 4 is preferably a methyl group, an ethyl group, or a phenyl group, and more preferably a methyl group. In addition, R 4 The monovalent saturated hydrocarbon group, aralkyl group and aryl group may have some or all of their hydrogen atoms substituted with halogen atoms, and specific examples thereof include R 1 Examples of the groups include the same groups as those exemplified in the above.

[0033] R 5 are each independently a hydrogen atom or a monovalent saturated hydrocarbon group having 1 to 8 carbon atoms; R 5 The monovalent saturated hydrocarbon group may be linear, branched, or cyclic. Specific examples thereof include R 1 Among the groups exemplified in , those having 1 to 8 carbon atoms can be mentioned. Among them, R 5 is preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, and further preferably a hydrogen atom.

[0034] X is a divalent hydrocarbon group having 2 to 8 carbon atoms, preferably a linear or branched divalent aliphatic hydrocarbon group. Specific examples thereof include alkylene groups such as ethylene, trimethylene, propylene, tetramethylene, hexamethylene, and octamethylene groups. Among them, an alkylene group having 2 or 3 carbon atoms is preferred, an alkylene group having 3 carbon atoms is more preferred, and a trimethylene group is even more preferred.

[0035] n is a number from 0 to 400. From the viewpoint of solubility, a number from 0 to 100 is preferred, a number of 0 or 1 is more preferred, and a number of 1 is even more preferred.

[0036] As the group represented by the above formula (II), R 4 is a methyl group, R 5 is a hydrogen atom, X is an alkylene group having 3 carbon atoms, and n is 1, which is preferred.

[0037] In formula (I), a is a number satisfying 0 ≦ a < 1. From the viewpoint of the crack suppression effect, a number satisfying 0 ≦ a ≦ 0.3 is preferred, and a = 0 is more preferred. b is a number satisfying 0 < b ≦ 1. From the viewpoint of the scratch resistance of the obtained cured product, a number satisfying 0.5 ≦ b ≦ 1 is preferred. c is a number satisfying 0 ≦ c ≦ 0.5. From the viewpoints of the curability of the composition and the hardness of the obtained cured product, a number satisfying 0 ≦ c ≦ 0.4 is preferred, and a number satisfying 0 ≦ c ≦ 0.3 is more preferred. d is a number satisfying 0 ≦ d < 1. From the viewpoints of the curability of the composition and the hardness of the obtained cured product, a number satisfying 0 ≦ d ≦ 0.2 is preferred, and d = 0 is more preferred. Note that a, b, c, and d are numbers satisfying a + b + c + d = 1.

[0038] e is a number satisfying 0 ≦ e ≦ 1. From the viewpoint of suppressing the condensation reaction by the condensable functional group, a number satisfying 0 ≦ e ≦ 0.8 is preferred. f is a number satisfying 0 < f < 4, and from the viewpoint of the crosslinking density of the cured product, a number satisfying 0.2 < f ≦ 2 is preferred, and a number satisfying 0.4 < f ≦ 1.1 is more preferred. Note that e and f are numbers satisfying 0 < e + f < 4, and a number satisfying 0.2 < e + f ≦ 2.8 is preferred.

[0039] (C) As the hydroxyl group-containing organopolysiloxane, in the above formula (I), R 1 is a methyl group or a phenyl group, R 2 is a methyl group, a is 0, b is a number satisfying 0.5 ≦ b ≦ 1, c is a number satisfying 0 ≦ c ≦ 0.5, d is 0, and a number satisfying a + b + c + d = 1, e is a number satisfying 0 ≦ e ≦ 0.8, f is a number satisfying 0.2 < f ≦ 2, and in the above formula (II), R 4 is a methyl group, R 5 is a hydrogen atom, X is an alkylene group having 3 carbon atoms, and n is 1 is preferred.

[0040] (C) The production method of the component is not particularly limited, and for example, it can be obtained by a production method including the following steps (α) and (β). (Step α): By a hydrolysis and condensation reaction of an organopolysiloxane represented by the following formula (I’) and a silane compound represented by the following formula (III) or by an equilibration reaction using an acid catalyst of an organopolysiloxane represented by the following formula (I’) and a disiloxane compound represented by the following formula (IV), a step of obtaining an organopolysiloxane having an SiH group

Chemical formula

Chemical formula

[0041] <(Step α)> (Step α) is a step of obtaining an organopolysiloxane having an SiH group by a hydrolysis condensation reaction of the organopolysiloxane represented by the above formula (I’) and the silane compound represented by the above formula (III) or by an equilibration reaction using an acid catalyst of the organopolysiloxane represented by the above formula (I’) and the disiloxane compound represented by the above formula (IV).

[0042] In formula (I’), g is a number satisfying 0 < g < 4, preferably a number satisfying 0.2 < g ≤ 2.8.

[0043] As the organopolysiloxane represented by formula (I’), R 1 is a methyl group or a phenyl group, R 2 is a methyl group, a is 0, b is a number satisfying 0.5 ≤ b ≤ 1, c is a number satisfying 0 ≤ c ≤ 0.5, d is 0, and a + b + c + d = 1, and g is a number satisfying 0.2 < g ≤ 2.8 are preferred.

[0044] The organopolysiloxane represented by formula (I’) can be produced according to a general method for producing organopolysiloxanes. For example, it can be obtained by hydrolysis condensation of a silane compound having a hydrolyzable group.

[0045] The silane compound having a hydrolyzable group is not particularly limited as long as it contains 1 to 4 chloro groups or alkoxy groups, which are hydrolyzable groups, on the silicon atom and has an organic substituent satisfying the above conditions. Specific examples thereof include tetrachlorosilane, tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane, methyltrichlorosilane, methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, methyltributoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldiisopropoxysilane, trimethylchlorosilane, trimethylmethoxysilane, trimethylethoxysilane, trimethylisopropoxysilane, ethyltrichlorosilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrichlorosilane, propyltrimethoxysilane, propyltriethoxysilane, butyltrichlorosilane, butyltrimethoxysilane, butyltriethoxysilane, hexyltrichlorosilane, hexyltrimethoxysilane, hexyltriethoxysilane, phenyl Examples of suitable silanes include trichlorosilane, phenyltrimethoxysilane, phenyltriethoxysilane, cyclohexyltrichlorosilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, propylmethyldichlorosilane, propylmethyldimethoxysilane, propylmethyldiethoxysilane, hexylmethyldichlorosilane, hexylmethyldimethoxysilane, hexylmethyldiethoxysilane, phenylmethyldichlorosilane, phenylmethyldimethoxysilane, phenylmethyldiethoxysilane, diphenyldichlorosilane, diphenyldimethoxysilane, diphenyldiethoxysilane, dimethylphenylchlorosilane, dimethylphenylmethoxysilane, dimethylphenylethoxysilane, and partial hydrolysates thereof. From the viewpoints of operability, ease of distilling off by-products, and ease of availability of raw materials, methoxysilane and ethoxysilane are preferred. The above silane compounds may be used alone or in combination of two or more.

[0046] A hydrolysis catalyst may be used when carrying out the hydrolysis. Conventionally known catalysts can be used as the hydrolysis catalyst, and those (acid catalysts) whose aqueous solutions show an acidity of pH 2 to 7 are preferred, and particularly preferred are acidic hydrogen halides, sulfonic acids, carboxylic acids, acidic or weakly acidic inorganic salts, solid acids such as ion exchange resins, and the like. Specific examples of acidic catalysts include hydrogen fluoride, hydrochloric acid, nitric acid, sulfuric acid, methanesulfonic acid, p-toluenesulfonic acid, formic acid, acetic acid, maleic acid, benzoic acid, lactic acid, phosphoric acid, and cation exchange resins having sulfonic acid or carboxylic acid groups on the surface.

[0047] The amount of the hydrolysis catalyst used is not particularly limited, but in order to ensure that the reaction proceeds quickly and to facilitate easy removal of the catalyst after the reaction, it is preferably 0.0002 to 0.5 mol per mol of hydrolyzable silane.

[0048] The mass ratio of the silane compound having a hydrolyzable group to the water required for the hydrolysis condensation reaction is not particularly limited, but in order to prevent the deactivation of the catalyst and to allow the reaction to proceed sufficiently, and also in consideration of the ease of removing water after the reaction, a ratio of 0.1 to 10 moles of water per mole of hydrolyzable silane is preferred. The reaction temperature during hydrolysis and condensation is not particularly limited, but in consideration of improving the reaction rate and preventing decomposition of the organic functional group, it is preferably −10 to 150° C. The reaction time is not particularly limited, but is preferably 0.5 to 6 hours.

[0049] In addition, an organic solvent may be used during the hydrolysis and condensation. Specific examples of the organic solvent that can be used include methanol, ethanol, propanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, toluene, and xylene.

[0050] In the above formula (III), R 6Examples of the halogen atom in R include fluorine, chlorine, bromine, and iodine atoms, and examples of the alkoxy group having 1 to 4 carbon atoms include methoxy, ethoxy, n-propoxy, and n-butoxy groups. 6 is preferably a chlorine atom, a hydroxyl group, a methoxy group or an ethoxy group.

[0051] Specific examples of the silane compound represented by the above formula (III) include methoxysilane, dimethylmethoxysilane, ethoxysilane, dimethylethoxysilane, chlorosilane, dimethylchlorosilane, and dimethylhydroxysilane.

[0052] Specific examples of the disiloxane compound represented by the above formula (IV) include 1,1,3,3-tetramethyldisiloxane.

[0053] In the step of obtaining an organopolysiloxane having SiH groups by the hydrolysis and condensation reaction of an organopolysiloxane represented by the above formula (I') with a silane compound represented by the above formula (III), the conditions for the hydrolysis and condensation reaction are not particularly limited, but can be the same as those for producing the organopolysiloxane represented by the above formula (I'). In this case, the ratio of the organopolysiloxane represented by formula (I') above to the silane compound represented by formula (III) above to be used is not particularly limited, but the amount of the silane compound represented by formula (III) above is preferably 5 to 80 parts by mass, and more preferably 10 to 70 parts by mass, per 100 parts by mass of the organopolysiloxane represented by formula (I') above. The amount of the hydrolysis catalyst used is not particularly limited, but is preferably 0.0002 to 0.5 moles per mole of the silane compound represented by formula (III).

[0054] The mass ratio of the hydrolyzable group contained in the organopolysiloxane represented by the above formula (I') to the water required for the hydrolysis condensation reaction is not particularly limited, but since the reaction rate can be changed by the amount of water added, a mass ratio according to the desired reaction rate is preferred. From the viewpoint of ensuring storage stability by reducing the number of highly active alkoxy groups at the organopolysiloxane terminals, the reaction rate of the alkoxy groups is preferably 50 to 100%, more preferably 60 to 100%.

[0055] On the other hand, in the process of obtaining an organopolysiloxane having SiH groups by an equilibration reaction (siloxane bond cleavage / rebonding reaction) between an organopolysiloxane represented by the above formula (I') and a disiloxane compound represented by the above formula (IV) using an acid catalyst, the equilibration reaction conditions are not particularly limited, but can be performed, for example, at 20 to 150°C for about 0.5 to 6 hours, preferably at 20 to 100°C for about 1 to 4 hours. In this case, a solvent may be added as necessary. Examples of the solvent include alcohol solvents such as methanol, ethanol, and isopropyl alcohol; and aromatic non-polar solvents such as benzene, toluene, and xylene.

[0056] The proportions of the organopolysiloxane represented by formula (I') and the disiloxane compound represented by formula (IV) used are not particularly limited, but the proportion of the disiloxane compound represented by formula (IV) used per 100 parts by mass of the organopolysiloxane represented by formula (I') is preferably 10 to 70 parts by mass, and more preferably 20 to 60 parts by mass.

[0057] As the acidic catalyst for promoting the equilibration reaction, a strong acid is preferred, and although there is no particular restriction on the type, sulfuric acid, methanesulfonic acid, trifluoromethanesulfonic acid, etc. can be suitably used, and in view of ease of post-treatment, a cation exchange resin having these exchange groups is particularly preferred. The amount of the acid catalyst added is preferably 100 to 10,000 ppm, and more preferably 500 to 3,000 ppm, based on the total mass of the organopolysiloxane represented by formula (I') above and the disiloxane compound represented by formula (IV) above.

[0058] In addition, water may be added during the equilibration reaction to promote the hydrolysis and condensation reaction between the organopolysiloxane represented by the above formula (I') and the disiloxane compound represented by the above formula (IV). The amount of water used is not particularly limited, but since the reaction rate can be changed by the amount of water added, a mass ratio according to the desired reaction rate is preferred. From the viewpoint of ensuring storage stability by reducing the number of highly active alkoxy groups at the organopolysiloxane terminals, the reaction rate of the alkoxy groups is preferably 50 to 100%, more preferably 60 to 100%.

[0059] <(Process β)> (Step β) is a step in which the organopolysiloxane having SiH groups obtained in (Step α) above is subjected to a hydrosilylation reaction with the compound represented by formula (V) above to obtain an organopolysiloxane containing hydroxyl groups.

[0060] In the above formula (V), R 7 As the monovalent aliphatic unsaturated hydrocarbon group having 2 to 8 carbon atoms, those having 2 to 6 carbon atoms are preferable, and specific examples thereof include alkenyl groups such as vinyl, allyl, 3-butenyl, 5-hexenyl, and 7-octenyl groups, with the vinyl group and allyl group being preferable, and the allyl group being more preferable.

[0061] As the compound represented by the above formula (V), in consideration of compatibility with the organopolysiloxane, vinyl alcohol, allyl alcohol, and ethylene glycol monoallyl ether are preferred, and ethylene glycol monoallyl ether is more preferred.

[0062] The amount of the compound represented by formula (V) used in the hydrosilylation reaction is preferably 1 mole or more per mole of SiH groups in the organopolysiloxane having SiH groups obtained in (step α).

[0063] The hydrosilylation reaction is preferably carried out in the presence of a catalyst.As the hydrosilylation reaction catalyst, a compound containing a platinum group metal such as platinum, rhodium, or palladium can be used.Among these, a compound containing platinum is preferred, and examples thereof include platinum black, chloroplatinic acid, alcohol-modified chloroplatinic acid, complexes of chloroplatinic acid with olefin, vinylsiloxane, acetylene alcohol, etc., platinum carbonylvinylmethyl complex, platinum-divinyltetramethyldisiloxane complex, platinum-cyclovinylmethylsiloxane complex, platinum-octylaldehyde / octanol complex, etc. The amount added may be a so-called catalytic amount capable of promoting the addition reaction, and is usually 0.1 to 500 ppm, preferably 1 to 200 ppm, calculated as the mass of the platinum group metal relative to the mass of the compound represented by formula (V) above.

[0064] The conditions for the hydrosilylation reaction are not particularly limited, but for example, a reaction temperature of 20 to 120° C. and a reaction time of 1 to 8 hours are preferred, and a reaction temperature of 20 to 100° C. and a reaction time of 1 to 6 hours are more preferred.

[0065] The weight average molecular weight (Mw) of component (C) in terms of polystyrene measured by gel permeation chromatography (GPC) is preferably 1,000 to 500,000, and more preferably 1,500 to 10,000. If the weight average molecular weight is 1,000 or more, storage stability and flex resistance are excellent, and if it is 500,000 or less, there is no risk of unevenness or coating irregularities occurring during coating. As the GPC measurement conditions, for example, the method used in the Examples below can be adopted.

[0066] The kinetic viscosity of component (C) at 25°C is 5 to 2,000 mm 2 / s is preferable, and 20 to 1,000 mm 2 / s is more preferable. 5mm2 / s or more, it has better storage stability and bending resistance, and 2 If the viscosity is less than 1 / s, there is no risk of unevenness or coating irregularities occurring during painting. The kinetic viscosity can be measured, for example, using a Canon-Fenske viscometer.

[0067] From the standpoint of storage stability and adhesion to substrates, the amount of alkoxy groups in component (C) is preferably 0.5 to 10% by mass based on the organopolysiloxane.

[0068] The amount of hydroxyl groups contained in component (C) is not particularly limited, but from the viewpoints of the viscosity of component (C) and the crosslink density, chemical resistance, stain resistance, and weather resistance of the resulting cured film, the hydroxyl value is preferably 50 to 500 mgKOH / g, and more preferably 70 to 300 mgKOH / g.

[0069] The blending amount of component (C) is 5 to 500 parts by mass, preferably 5 to 100 parts by mass, and more preferably 5 to 50 parts by mass, of the nonvolatile content per 100 parts by mass of the nonvolatile content of component (A). If the amount of component (C) is less than the above range, the weather resistance and stain resistance of the obtained cured film will be insufficient, whereas if it is too much, the chemical resistance, hardness, and weather resistance will be insufficient. The component (C) may be a single composition, or a mixture of multiple compounds having different compositions.

[0070] (4)(D) Curing catalyst The coating composition of the present invention may contain a curing catalyst. The curing catalyst is not particularly limited as long as it is one generally used in organosiloxane-based coatings, but is preferably an organometallic compound, such as a metal alkoxide compound of Ti, Al, Zr, Sn, etc., a metal chelate compound, or a metal ester compound, and is preferably one containing an organotin compound.

[0071] Specific examples of the metal alkoxide compound include aluminum alkoxides such as aluminum trimethoxide, aluminum triethoxide, aluminum tri-n-propoxide, aluminum triisopropoxide, aluminum tri-n-butoxide, aluminum triisobutoxide, aluminum tri-s-butoxide, and aluminum tri-t-butoxide; tetramethyl titanate, tetraethyl titanate, tetra-n-propyl titanate, tetraisopropyl titanate, tetra-n-butyl titanate, tetraisobutyl titanate, tetra-t-butyl titanate, and tetra-n-hexyl titanate. Examples of the zirconium alkoxide include titanium alkoxides such as tetraethyl zirconate, tetra-n-propyl zirconate, tetraisopropyl zirconate, tetra-n-butyl zirconate, tetra-s-butyl zirconate, tetra-t-butyl zirconate, tetra-n-pentyl zirconate, tetra-t-pentyl zirconate, tetra-t-hexyl zirconate, tetra-n-heptyl zirconate, tetra-n-octyl zirconate, tetra-n-stearyl zirconate, and dibutyltin dibutoxide.

[0072] Specific examples of metal chelate compounds include aluminum tris(ethylacetoacetate), aluminum tris(n-propylacetoacetate), aluminum tris(isopropylacetoacetate), aluminum tris(n-butylacetoacetate), aluminum isopropoxybis(ethylacetoacetate), aluminum tris(acetylacetonato), aluminum tris(propionylacetonato), aluminum diisopropoxypropionylacetonato, aluminum acetylacetonato·bis(propionylacetonato), aluminum monoethylacetoacetate·bis(acetylacetonato), aluminum acetylacetonato·di-s-butylate, aluminum methylacetoacetate·di-s-butylate, aluminum di(methylacetoacetate)·mono-tert-butylate, aluminum diisopropoxyethylacetoacetate, aluminum monoacetylacetonato, aluminum acetylacetonato·di-s-butylate, aluminum methylacetoacetate·di-s-butylate, aluminum di(methylacetoacetate)·mono-tert-butylate, aluminum diisopropoxyethylacetoacetate, aluminum monoacetylacetonato, aluminum acetylacetonato·di-s-butylate, aluminum methylacetoacetate·di-s-butylate, aluminum di(methylacetoacetate)·mono-tert-butylate, aluminum diisopropoxyethylacetoacetate, aluminum monoacetylacetonato, aluminum acetylacetonato·di-s-butylate, aluminum di ... Examples of suitable chelate compounds include aluminum chelate compounds such as acetonato bis(ethylacetoacetate)aluminum; titanium chelate compounds such as diisopropoxy bis(ethylacetoacetate)titanate, diisopropoxy bis(acetylacetonato)titanate, and di-n-butoxy bis(acetylacetonato)titanate; zirconium chelate compounds such as tetrakis(acetylacetonato)zirconium, tetrakis(n-propylacetoacetate)zirconium, and tetrakis(ethylacetoacetate)zirconium; and tin chelate compounds such as dibutyltin diacetate, dibutyltin di(2-ethylhexyl)ate, dibenzyltin di(2-ethylhexyl)ate, dibutyltin dilaurate, dibutyltin diisooctylmaleate, and dibutyltin bis(acetylacetonate). The use of tin chelate compounds is preferred in terms of the chemical resistance of the coating film formed.

[0073] As the tin ester compound, commercially available products can be used, such as Neostan U-100, U-130, U-200, U-220H, U-303, U-700, U-810, U-820, and U-830 (all manufactured by Nitto Kasei Co., Ltd.), and BT-120S (manufactured by Kaneka Corporation).

[0074] When component (D) is added, the amount added should be an amount sufficient to cure the composition, but typically, the amount is preferably 0.01 to 20 parts by mass, and more preferably 0.1 to 10 parts by mass, per 100 parts by mass of the nonvolatile content of component (A). The curing catalyst of the component (D) may use either a single type alone or a combination of two or more types.

[0075] (5) Optional ingredients The coating composition of the present invention may contain any suitable additives within the range that does not impair the effects of the present invention. Specific examples of the additives include solvents, non-reactive silicone oils, reactive silicone oils, adhesion promoters such as silane coupling agents, non-reactive polymer resins, fillers, leveling agents, rheology adjusters, reactive diluents, non-reactive diluents, surfactants, dispersants, defoamers, dehydrating agents, antioxidants, antioxidants, antistatic agents, infrared absorbers, ultraviolet absorbers, light stabilizers, fluorescent agents, dyes, pigments, fragrances, abrasives, rust inhibitors, and thixotropy-imparting agents. These may be used alone or in combination of two or more.

[0076] Examples of the solvent include aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatic hydrocarbons such as pentane, hexane, heptane, and decane; ethers such as diethyl ether and tetrahydrofuran; esters such as ethyl acetate and butyl acetate; and ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone. These may be used alone or in combination of two or more. When the coating composition of the present invention contains a solvent, the content thereof is preferably 1 to 50 parts by mass, and more preferably 5 to 20 parts by mass, per 100 parts by mass of the total nonvolatile content of components (A) to (C).

[0077] Examples of pigments include color pigments such as titanium oxide, red iron oxide, cyanine color pigments, carbon black, and zircon powder; extender pigments such as silica, baryta powder, precipitated barium sulfate, barium carbonate, calcium carbonate, gypsum, clay, white carbon, diatomaceous earth, talc, magnesium carbonate, alumina white, gloss white, and calcium carbonate; zinc phosphate, zinc phosphosilicate, zinc aluminum phosphate, zinc calcium phosphate, calcium phosphate, aluminum pyrophosphate, calcium pyrophosphate, aluminum dihydrogen tripolyphosphate, aluminum metaphosphate, calcium metaphosphate, zinc oxide, zinc phosphomolybdate, and phosphomolybdate. Examples of suitable pigments include aluminum phosphate, zinc, zinc oxide, zinc molybdate, calcium molybdate, borates, barium metaborate, zinc calcium cyanamide, calcium silicate, calcium metasilicate; modified silica in which cations such as calcium, zinc, cobalt, lead, strontium, barium, etc. are bound to porous silica particles; ion-exchanged silica obtained by binding cations by ion exchange; and rust-preventive pigments such as vanadium-based compounds such as aluminum pyrophosphate, vanadium pentoxide, calcium vanadate, and ammonium metavanadate. These may be used alone or in combination of two or more.

[0078] When the coating composition of the present invention contains a pigment, the content thereof is preferably 5 to 100 parts by mass, and more preferably 30 to 90 parts by mass, in terms of non-volatile matter per 100 parts by mass of the total non-volatile matter of components (A) to (C), from the viewpoint of the weather resistance of the coating film to be formed.

[0079] (6) Manufacturing method The coating composition of the present invention can be obtained by mixing and stirring the above-mentioned components (A), (B), (C), and optionally the component (D) and optional components in any order. The mixing conditions are not particularly limited, but in consideration of workability and the stability of the coating composition, it is preferable to mix at 10 to 40°C.

[0080] The viscosity of the coating composition of the present invention is not particularly limited, but in consideration of improving molding or coating workability and suppressing the occurrence of streaks, etc., the viscosity at 25°C measured with a rotational viscometer is preferably 100,000 mPa·s or less, more preferably 20,000 mPa·s or less. The lower limit of the viscosity is not particularly limited, but is preferably 10 mPa·s or more.

[0081] (7) Cured films of coating compositions and coated articles The coating composition of the present invention is applied to an object to be coated and then cured to obtain a cured film and a coated article. There are no limitations on the application method, and known methods such as spray coating, roller coating, brush coating, flow coating, etc. can be used. The coating composition of the present invention can be cured at room temperature, but may be heated as necessary to accelerate curing. The heating temperature is preferably 40 to 150° C., which enables the formed cured coating film to exhibit excellent weather resistance, chemical resistance, and stain resistance.

[0082] Substrates to be coated include glass and metal materials which have been primed as desired, such as steel sheets, galvanized steel sheets, stainless steel, aluminum, etc.; alkaline substrates such as concrete, mortar, slate, slate roofing tiles, etc.; ceramic building materials; plastics; and those with old coating films formed thereon.

[0083] Applications of the coating composition of the present invention include, but are not limited to, heavy-duty anticorrosive coating applications for steel structures such as bridges, transmission towers, plants, and tanks.

[0084] The coating composition of the present invention has excellent long-term weather resistance, and the composition alone provides a cured film that protects the substrate from harsh environments and maintains its beautiful appearance, but if necessary, a known undercoat and / or intermediate coat layer may be provided.

[0085] Examples of the undercoat paint include epoxy resin paint, modified epoxy resin paint, epoxy resin-based glass flake paint, epoxy resin coating material, ultra-thick film epoxy resin paint, epoxy resin zinc-rich paint, inorganic zinc-rich paint, chlorinated rubber resin-based paint, phthalic acid resin-based paint, epoxy ester resin paint, etc., and examples of the intermediate coat paint include epoxy resin-based paint, polyurethane-based paint, epoxy resin MIO paint, phenolic resin MIO paint, chlorinated rubber resin-based paint, phthalic acid resin-based paint, etc. EXAMPLES

[0086] The present invention will be described in more detail below with reference to Synthesis Examples, Examples, and Comparative Examples, but the present invention is not limited to the following Examples. The kinematic viscosity is a value measured at 25°C using a Cannon-Fenske viscometer, the hydroxyl value is a value measured by neutralization titration method in accordance with JIS K 1557-1:2007, the isocyanate content is the amount of isocyanate groups present in the sample expressed as a mass fraction in accordance with JIS K 1603-1:2007, and the average composition of the organopolysiloxane is a value measured by NMR measurement using a JEOL Ltd. NMR measurement device. 1 H-NMR and 29 The value is calculated from the integrated value of the Si-NMR spectrum, and the weight average molecular weight (Mw) is a polystyrene equivalent value determined by GPC (gel permeation chromatography) measurement under the following conditions. [GPC conditions] Equipment: HLC-8220 (Tosoh Corporation) Columns: TSKgel GMHXL-L, TSKgel G4000HXL, TSKgel G2000HXL x 2 Developing solvent: Tetrahydrofuran (THF) Flow rate: 1mL / min Detector: RI Column thermostat temperature: 40℃ Standard material: polystyrene

[0087] [1] Synthesis of hydroxyl-containing organopolysiloxane Using the organopolysiloxanes listed below as raw materials, hydroxyl-containing organopolysiloxanes were produced. <Raw material organopolysiloxane> Organopolysiloxane 1: In the above formula (I′), a=0, b=0.6, c=0.4, d=0, g=1.1, R 1 : Methyl group, phenyl group, R 2 : Organopolysiloxane represented by methyl groups (weight average molecular weight 1,500, dynamic viscosity 100 mm 2 / s) Organopolysiloxane 2: In the above formula (I′), a=0, b=0.9, c=0.1, d=0, g=1.3, R 1 : Methyl group, phenyl group, R 2 : Organopolysiloxane represented by methyl groups (weight average molecular weight 1,800, dynamic viscosity 70 mm 2 / s)

[0088] [Synthesis Example 1-1] In a 500 mL separable flask equipped with a stirrer, reflux condenser, dropping funnel and thermometer, 100 parts by mass of organopolysiloxane A, 55 parts by mass of tetramethyldisiloxane, 35 parts by mass of methanol and 2 parts by mass of strong acid cation exchange resin (Lewatit K2629 manufactured by LANXESS) were added, and 11 parts by mass of water was added dropwise while stirring. After stirring for 3 hours at 25°C, the reaction liquid obtained was filtered. Next, the fraction was removed by distillation under reduced pressure (90°C, 1.3 kPa). 1 H-NMR and 29 The reaction rate of the Si-OCH3 group calculated from the integral value of the detection spectrum in Si-NMR was 80%. Further, 0.1 parts by mass of a 1,3-divinyltetramethyldisiloxane complex of Pt(0) and 64 parts by mass of ethylene glycol monoallyl ether were added thereto and heated at 80°C for 4 hours, after which unreacted ethylene glycol monoallyl ether was removed by vacuum distillation (90°C, 1.3 kPa) to obtain a hydroxyl group-containing organopolysiloxane (C-1) (yield 150 parts by mass).

[0089] [Synthesis Example 1-2] A hydroxyl-containing organopolysiloxane (C-2) was obtained in the same manner as in Synthesis Example 1-1, except that the raw material organopolysiloxane 1 was changed to organopolysiloxane 2.

[0090] The values ​​of e and f in formula (I), the weight average molecular weight, and the hydroxyl value of the resulting organopolysiloxane are shown in Table 1.

[0091] [Table 1]

[0092] [2] Preparation of coating composition [Examples 1-1 to 1-8, Comparative Examples 1-1 to 1-4] The following components were mixed at 25° C. in the composition ratios (mass ratios) shown in Table 2 to prepare curable compositions (i) to (xii). <Component (A)> (A-1): Acrydic A-801P (a toluene-butyl acetate solution of acrylic polyol, non-volatile content 50% by mass, hydroxyl value 50 mg KOH / g, manufactured by DIC Corporation) (A-2): Burnock D-220 (polyester polyol, non-volatile content 100% by mass, hydroxyl value 147 mg KOH / g, manufactured by DIC Corporation) <(B) component> (B-1): Burnock DN-901S (polyisocyanate, non-volatile content 100% by mass, isocyanate content 23.1% by mass, manufactured by DIC Corporation) (B-2): Duranate TPA-100 (polyisocyanate, non-volatile content 100% by mass, isocyanate content 23.2% by mass, manufactured by Asahi Kasei Corporation) <(C) component> (C-1) Hydroxyl-containing organopolysiloxane obtained in Synthesis Example 1-1 above (C-2) Hydroxyl-containing organopolysiloxane obtained in Synthesis Example 1-2 above <(D) component> (D): Neostan U-810 (dioctyl tin, manufactured by Nitto Kasei Co., Ltd.) <(E) component> (E): Ethyl acetate / butyl acetate mixed solvent (mass ratio 1:1)

[0093] [Table 2]

[0094] [3] Manufacturing and evaluation of coated articles [Examples 2-1 to 2-8, Comparative Examples 2-1 to 2-4] The coating compositions (i) to (xii) obtained in Examples 1-1 to 1-8 and Comparative Examples 1-1 to 1-4 were applied onto a metal substrate by flow coating to a dry coating thickness of 30 μm, and then cured for 7 days under conditions of 23°C and 50% RH to obtain a coating. The resulting coated article was evaluated for coating appearance, rubbing test, antifouling test, and accelerated weather resistance. The results are shown in Table 3. (1) Coating appearance When visually inspected, the coating film surface was uniform and free of irregularities or cracks caused by aggregates, and was marked with an "O"; the coating film surface was non-uniform and whitening or irregularities or cracks caused by aggregates were observed, and marked with an "X." (2) Rubbing test Acetone was added to a BEMCOT M-3II (area 4 cm 2 The surface was immersed in a rubbing agent (manufactured by Asahi Kasei Corporation) and rubbed back and forth 30 times with a load of 500 gf, and the appearance of the coating was evaluated visually. After the rubbing test, coating appearance that showed no change from before the test was evaluated as ○, and coating peeling or whitening was observed was evaluated as ×. (3) Antifouling test A line was drawn on the test surface with an oil-based marker pen (organic solvent type marker, product name: Makki Extra Fine, manufactured by Zebra Co., Ltd.), and left for 3 hours. Then, a BEMCOT M-3II (area 4 cm2) was immersed in a mixed solvent of ethanol:toluene (1:1 by mass). 2 After the test, the amount of ink remaining on the coating was visually observed and rated on a two-level scale. ○: No significant change was observed compared to the current test piece. ×: Ink remains compared to the current test piece. (4) Accelerated weather resistance The accelerated weather resistance test was carried out using an ultra-accelerated weather resistance tester (Eye Super UV Tester, manufactured by Iwasaki Electric Co., Ltd.). The test specimens used were polyester-coated steel plates (0.8 mm x 70 mm x 60 mm). The test conditions were 8 hours of irradiation (ultraviolet irradiance 90 mW, black panel temperature 63°C, 70% RH), 4 hours of darkness (black panel temperature 63°C, 70% RH), and 4 hours of condensation (black panel temperature 30°C, 90% RH), with 30 cycles of testing, each consisting of 16 hours. After the test, the coating was visually observed for swelling, cracking, peeling, and changes in gloss, and was evaluated on a two-level scale. ○: No significant change was observed compared to the current test piece. ×: Loss of luster, cracks, or peeling compared to the current test piece.

[0095] [Table 3]

[0096] As shown in Table 2, the cured films obtained in Examples 2-1 to 2-8 were excellent in appearance and solvent resistance, as well as in antifouling property and weather resistance. On the other hand, the cured films obtained from the curable composition not having the (C) component and the curable composition having an insufficient amount of the (C) component (Comparative Examples 2-1 and 2-2) are excellent in appearance and solvent resistance, but do not exhibit the antifouling property and weather resistance that are characteristic of silicone. In addition, the cured film of Comparative Example 2-3, in which NCO / OH is less than 0.8, is insufficiently crosslinked, resulting in poor solvent resistance and weather resistance. Furthermore, the cured film of Comparative Example 2-4, in which NCO / OH is more than 1.4, shows some whitening in appearance and is also poor in antifouling property and weather resistance.

Claims

1. (A) one or more polyols selected from the group consisting of acrylic polyols, polyester polyols, and polyether polyols; (B) a compound having two or more isocyanate groups in one molecule, and (C) a hydroxyl-containing organopolysiloxane represented by the following formula (I): 5 to 500 parts by weight per 100 parts by weight of component (A) 【Chemistry 1】 (In the formula, R 1 are each independently a hydrogen atom, or a monovalent saturated hydrocarbon group having 1 to 12 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or an aryl group having 6 to 18 carbon atoms, each of which may be substituted with a halogen atom; R 2 is a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, or an i-propyl group, and R 3 is a group represented by the following formula (II), a, b, c, and d are numbers that satisfy 0≦a<1, 0<b≦1, 0≦c≦0.5, 0≦d<1, and a+b+c+d=1, and e and f are numbers that satisfy 0≦e≦1, 0<f<4, and 0<e+f<4. 【Chemistry 2】 (In the formula, R 4 are each independently a hydrogen atom, or a monovalent saturated hydrocarbon group having 1 to 12 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or an aryl group having 6 to 18 carbon atoms, each of which may be substituted with a halogen atom; R 5 are each independently a hydrogen atom or a monovalent saturated hydrocarbon group having 1 to 8 carbon atoms, X is a divalent hydrocarbon group having 2 to 8 carbon atoms, n is a number from 0 to 400, and * represents a bond to an oxygen atom. Including, The ratio of the number of isocyanate groups in the component (B) to the sum of the number of hydroxyl groups in the component (A) and the number of hydroxyl groups in the component (C) (NCO (B) / OH (A+C) ) is 0.8 to 1.

4.

2. 2. The coating composition according to claim 1, wherein the component (A) is an acrylic polyol, a polyester polyol, or both of these.

3. 2. The coating composition according to claim 1, wherein said component (B) is a polyisocyanate having two or more isocyanate groups in one molecule and containing no silicon atoms.

4. In the formula (I), R 1 2. The coating composition according to claim 1, wherein at least one of said groups is an aryl group having 6 to 18 carbon atoms.

5. In the formula (I), R 1 2. The coating composition according to claim 1, wherein each of the groups independently represents a methyl group or a phenyl group.

6. In the formula (I), R 2 2. The coating composition according to claim 1, wherein is a methyl group.

7. 2. The coating composition according to claim 1, wherein in said formula (I), b is a number satisfying 0.5≦b≦1.

8. 2. The coating composition according to claim 1, wherein in formula (I), a and d are 0.

9. In the formula (II), R 4 is a methyl group, R 5 2. The coating composition according to claim 1, wherein is a hydrogen atom, X is an alkylene group having 3 carbon atoms, and n is 1.

10. 2. The coating composition according to claim 1, wherein the weight average molecular weight (Mw) of component (C) in terms of polystyrene measured by gel permeation chromatography is 1,000 to 500,000.

11. The coating composition according to claim 1, further comprising (D) a curing catalyst.

12. The method for producing a coating composition according to any one of claims 1 to 11, wherein the components (A) to (C) are mixed at a temperature of 10 to 40°C.

13. A cured film formed from the coating composition according to any one of claims 1 to 11.

14. A coated article comprising a substrate and the cured film according to claim 13 formed on at least one surface of the substrate directly or via one or more other layers.