Paint composition, method for manufacturing 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 paint composition, a method for producing the same, and a coated article, and more specifically to a paint composition comprising an organic resin and an organopolysiloxane, a method for producing the paint composition, and a coated article having a cured film made of the paint composition. [Background technology]

[0002] Organopolysiloxanes containing alkoxysilyl groups are widely used in paints and coatings. Generally, organopolysiloxanes with alkoxy groups at their terminals react with each other when a curing catalyst is added and external energy such as heat energy is applied, forming a strong siloxane network. As a result, the resulting film has excellent heat resistance and weather resistance, and its application ranges from outdoor buildings to automotive parts and electronic components.

[0003] On the other hand, while organopolysiloxane-based coatings have the advantages mentioned above, they also have the disadvantages of a slow curing speed and poor crack resistance and flexibility of the resulting coating film.

[0004] To overcome these drawbacks, a conventional method has been known in which a composition obtained by mixing organopolysiloxane with an organic resin such as an alkyd resin, polyester resin, acrylic resin, or epoxy resin is used as a paint. As such a composition, Patent Document 1 proposes, for example, a paint composition containing a silyl group-containing vinyl polymer, a silanol group-containing organopolysiloxane, and an alkoxy group-containing organopolysiloxane. However, while this composition improves curability and crack resistance, it has the problem of reducing the chemical resistance, stain resistance, and weather resistance that are characteristic of organopolysiloxane-based resin coatings.

[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 has a problem in terms of versatility because synthetic equipment for composite resin is required. Therefore, a simple method for extracting the characteristics of both organopolysiloxane and organic resin is required.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0007] In view of the above circumstances, the present invention has been made, and an object thereof is to provide a coating composition containing an organic resin and an organopolysiloxane, which can be easily manufactured and gives a cured film having excellent chemical resistance, antifouling property, and weather resistance.

Means for Solving the Problems

[0008] As a result of intensive studies to achieve the above object, the present inventors have found that a coating composition obtained by mixing a polyol, a polyisocyanate, and a predetermined hydroxyl group-containing organopolysiloxane at a predetermined ratio can be cured at room temperature, and a coating film obtained from the composition satisfies chemical resistance, antifouling property, and weather resistance, and thus completed the present invention.

[0009] That is, the present invention is 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 with respect to 100 parts by mass of the component (A) [Chemical formula] (In the formula, R 1 is, independently of each other, 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, a + b + c + d = 1, and e and f are numbers satisfying 0 ≦ e ≦ 1, 0 <f <4, and 0 <e + f <4.) [Chemical formula] (In the formula, R 4 is, independently of each other, 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, independently of each other, 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.) containing 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 claim 1, wherein the component (A) is an acrylic polyol, a polyester polyol, or both of them. 3. The coating composition according to claim 1, wherein the component (B) is a polyisocyanate having two or more isocyanate groups in one molecule and no silicon atom. 4. In the formula (I), at least one of R 1 is an aryl group having 6 to 18 carbon atoms, according to the coating composition of claim 1. 5. In the formula (I), each R 1 is independently a methyl group or a phenyl group, according to the coating composition of claim 1. 6. In the formula (I), R 2 is a methyl group, according to the coating composition of claim 1. 7. In the formula (I), b is a number satisfying 0.5 ≦ b ≦ 1, according to the coating composition of claim 1. 8. In the formula (I), a and d are 0, according to the coating composition of claim 1. 9. In the 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, according to the coating composition of claim 1. 10. The coating composition according to claim 1, wherein the weight average molecular weight (Mw) in terms of polystyrene in the gel permeation chromatography of the component (C) is 1,000 to 500,000. 11. The coating composition according to claim 1, further comprising (D) a curing catalyst. 12. A method for producing the coating composition according to any one of claims 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 claims 1 to 11. 14. A coated article having a substrate and the cured film according to claim 13 formed directly or via one or more other layers on at least one surface of the substrate. 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 group-containing organosiloxane, and provides a cured film with excellent chemical resistance, stain resistance, and weather resistance, making it suitable for the manufacture of various coated articles. [Modes for carrying out the invention]

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

[0012] (1)(A) Polyol The polyol component (A) has two or more reactive hydroxyl groups in one molecule and reacts with component (B), which has isocyanate groups, in the presence or absence of the 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; polyester polyols, which are condensation polymers of a polybasic acid and a polyhydric alcohol (including alkyd polyols, which are condensation polymers of a polybasic acid and a fatty acid and a polyhydric alcohol); and polyether polyols, which are addition polymers of a polyhydric alcohol and an alkylene oxide. Among these, acrylic polyols and polyester polyols are preferred, and acrylic polyols are particularly preferred because they produce a coating film with excellent transparency and gloss. In this specification, (meth)acrylic monomer includes both acrylic monomer and methacrylic monomer.

[0014] Examples of hydroxyl group-containing (meth)acrylic monomers that 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 various hydroxyalkyl esters of α,β-ethylenically unsaturated carboxylic acids such as "Praxel FM or Praxel FA" [caprolactone addition monomers manufactured by Daicel Chemical Corporation], or adducts of these with ε-caprolactone. Among these, 2-hydroxyethyl (meth)acrylate is preferred because it reacts easily.

[0015] Other (meth)acrylic monomers copolymerizable with hydroxyl group-containing (meth)acrylic monomers are not particularly limited, and known monomers can be used. Vinyl monomers are also copolymerizable. For example, alkyl(meth)acrylates having alkyl groups with 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; acetic acid Examples include vinyl carboxylates such as vinyl, vinyl propionate, vinyl pivalate, and vinyl benzoate; alkyl esters of crotonic acids such as methyl crotate and ethyl crotate; dialkyl esters of unsaturated dibasic acids such as dimethyl malate, di-n-butyl malate, 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 monomers containing tertiary amide groups 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 using various polymerization methods such as bulk radical polymerization, solution radical polymerization, and non-aqueous dispersion radical polymerization, with solvents such as hydrocarbons like hexane, octane, toluene, and xylene, ketones like methyl ethyl ketone, esters like ethyl acetate, and alcohols like isopropyl alcohol, as needed, and 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 viewpoint of curability, weather resistance and paintability, the weight-average molecular weight (Mw) in terms of polystyrene in 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 a hydroxyl value of 10 to 200 mgKOH / g is preferred, and 20 to 180 mgKOH / g is more preferred. In this invention, the hydroxyl value is measured according to JIS K 1557-1:2007. Furthermore, component (A) may be used alone or in combination of two or more types.

[0018] (A) As components, commercially available products can be used, for example, Acrydic A-801P (acrylic polyol), Barnock D-220 (polyester polyol) (both manufactured by DIC Corporation), and Duranate TPA-100 (manufactured by Asahi Kasei Corporation).

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

[0020] As isocyanate compounds, known compounds such as aromatic, aliphatic, aromatic aliphatic, and alicyclic polyisocyanates, and organosilicon compounds having an isocyanate group can be used, but polyisocyanates without silicon atoms are preferred, and from the viewpoint of long-term outdoor use, aliphatic polyisocyanates mainly derived from aliphatic diisocyanates are preferred. 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 preferred from the viewpoint of the crack resistance of the resulting coating film and cost.

[0021] Examples of aliphatic polyisocyanates obtained from aliphatic diisocyanates include allophanate-type polyisocyanates, biuret-type polyisocyanates, adduct-type polyisocyanates, and isocyanurate-type polyisocyanates, all of which can be suitably used.

[0022] Furthermore, as the aforementioned polyisocyanates, so-called blocked polyisocyanate compounds, which are blocked with various blocking agents, can also be used. Examples of blocking agents that can be used include alcohols such as methanol, ethanol, and lactic acid 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 component (B) is not particularly limited, but the isocyanate content is preferably 5 to 50% by mass, and more preferably 10 to 40% by mass. In this invention, the isocyanate content is the value according to JIS K1603-1:2007.

[0024] (B) As 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) is 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 later (NCO (B) / OH (A+C) The amount is such that the ratio is 0.8 to 1.4, but preferably 0.9 to 1.2. If it is less than 0.8, the resulting cured film will have poor chemical resistance and weather resistance, and if it is greater than 1.4, the resulting cured film will have poor antifouling and weather resistance. Furthermore, component (B) may be used alone or in combination of two or more types.

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

[0027] [ka]

[0028] In equation (I), R 1 These are, independently, 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 hydrogen atom or a halogen atom.

[0029] R 1 The monovalent saturated hydrocarbon group having 1 to 12 carbon atoms may be linear, branched, or cyclic. Specific examples 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. Preferably, the alkyl group has 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms, with methyl and ethyl groups being even more preferred. As for aralkyl groups having 7 to 20 carbon atoms, those having 7 to 10 carbon atoms are preferred, and specific examples include the benzyl group and the phenylethyl group. As for aryl groups having 6 to 18 carbon atoms, those having 6 to 10 carbon atoms are preferred. Specific examples 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 phenyl groups being preferred. Among these, R 1 A methyl group or a phenyl group is preferred. Furthermore, the above monovalent saturated hydrocarbon group, aralkyl group, and aryl group may have some or all of its hydrogen atoms substituted with halogen atoms (fluorine, chlorine, bromine, or iodine atoms). Specific examples 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 The group is a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, or an i-propyl group, with a methyl group, an ethyl group, an n-propyl group, or an i-propyl group being preferred, a methyl group or an ethyl group being more preferred, and a methyl group being even more preferred.

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

[0032] In equation (II), R 4 These are, independently, monovalent saturated hydrocarbon groups having 1 to 12 carbon atoms, aralkyl groups having 7 to 20 carbon atoms, or aryl groups having 6 to 18 carbon atoms, which may each be substituted with a hydrogen atom or a halogen atom. Specific examples of these monovalent saturated hydrocarbon groups, aralkyl groups, and aryl groups are, respectively, the R groups mentioned above. 1 Examples of the same groups as those exemplified above include, among them, R 4 The group is preferably a methyl group, an ethyl group, or a phenyl group, with a methyl group being more preferred. Note, R 4 The monovalent saturated hydrocarbon group, aralkyl group, and aryl group may have some or all of its hydrogen atoms substituted with halogen atoms, a specific example of which is R 1 Examples similar to the base exemplified above can be given.

[0033] R 5 Each is independently a hydrogen atom or a monovalent saturated hydrocarbon group having 1 to 8 carbon atoms, and R 5 The monovalent saturated hydrocarbon group can be linear, branched, or cyclic, and a specific example is R 1 Examples include those with 1 to 8 carbon atoms, similar to the groups exemplified above. Among them, R 5 The atom 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 even more 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, octamethylene groups, etc. Among them, an alkylene group having 2 or 3 carbon atoms is preferable, an alkylene group having 3 carbon atoms is more preferable, and a trimethylene group is even more preferable.

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

[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 is preferable.

[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 preferable, and a = 0 is more preferable. 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 preferable. 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 preferable, and a number satisfying 0 ≦ c ≦ 0.3 is more preferable. 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 preferable, and d = 0 is more preferable. 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 preferable. f is a number satisfying 0 < f < 4, but from the viewpoint of the crosslink density of the cured product, a number satisfying 0.2 < f ≤ 2 is preferable, and a number satisfying 0.4 < f ≤ 1.1 is more preferable. Note that e and f are numbers satisfying 0 < e + f < 4, and a number satisfying 0.2 < e + f ≤ 2.8 is preferable.

[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 preferable.

[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): An organopolysiloxane having a SiH group is obtained by a hydrolysis 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).

Chemical formula

Chemical formula

[0041] <(Step α)> (Step α) is a step of obtaining an organopolysiloxane having a 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 a silicon atom and has an organic substituent satisfying the above conditions. Specific examples 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 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. However, due to ease of handling, ease of removing by-products, and availability of raw materials, methoxysilane and ethoxysilane are preferred. The silane compounds mentioned above may be used individually or in combination of two or more.

[0046] A hydrolysis catalyst may be used when carrying out hydrolysis. Conventional known catalysts can be used as hydrolysis catalysts, and those whose aqueous solution exhibits acidity with a pH of 2 to 7 (acidic catalysts) are preferred, and in particular, acidic hydrogen halides, sulfonic acids, carboxylic acids, acidic or weakly acidic inorganic salts, solid acids such as ion exchange resins are preferred. 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 their surface.

[0047] The amount of hydrolysis catalyst used is not particularly limited, but considering the need to allow the reaction to proceed rapidly and the ease of removing the catalyst after the reaction, 0.0002 to 0.5 moles per mole of hydrolyzable silane is preferred.

[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 considering the need to prevent catalyst deactivation and allow the reaction to proceed sufficiently, as well as 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 condensation is not particularly limited, but -10 to 150°C is preferred to improve the reaction rate and prevent the decomposition of organic functional groups. The reaction time is not particularly limited, but 0.5 to 6 hours is preferred.

[0049] Furthermore, organic solvents may be used during hydrolysis condensation. Specific examples of usable organic solvents include methanol, ethanol, propanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, toluene, and xylene.

[0050] In the above equation (III), R 6Examples of halogen atoms include fluorine, chlorine, bromine, and iodine atoms, and examples of alkoxy groups with 1 to 4 carbon atoms include methoxy, ethoxy, n-propoxy, and n-butoxy groups. Among these, R 6 The preferred element is a chlorine atom, a hydroxyl group, a methoxy group, or an ethoxy group.

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

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

[0053] In the process of obtaining an organopolysiloxane having an SiH group by a hydrolysis condensation reaction between an organopolysiloxane represented by formula (I') and a silane compound represented by formula (III), the conditions for the hydrolysis condensation reaction are not particularly limited, but can be carried out under the same conditions as for the production of the organopolysiloxane represented by formula (I'). In this case, the ratio of the organopolysiloxane represented by formula (I') to the silane compound represented by formula (III) is not particularly limited, but it is preferable that the amount of the silane compound represented by formula (III) is 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'). The amount used when using the hydrolysis catalyst is not particularly limited, but 0.0002 to 0.5 moles is preferred per mole of the silane compound represented by formula (III).

[0054] The mass ratio of the hydrolyzable group in the organopolysiloxane represented by 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 corresponding 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 terminus, the reaction rate of the alkoxy groups is preferably 50 to 100%, and more preferably 60 to 100%.

[0055] On the other hand, in the step of obtaining an organopolysiloxane having a SiH group by an acid-catalyzed equilibration reaction (cleavage / recombination reaction of siloxane bonds) between an organopolysiloxane represented by formula (I') and a disiloxane compound represented by formula (IV), the conditions for the equilibration reaction are not particularly limited, but can be carried out, 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 process, adding a solvent is optional, if necessary. Examples of solvents include alcoholic solvents such as methanol, ethanol, and isopropyl alcohol; and aromatic nonpolar solvents such as benzene, toluene, and xylene.

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

[0057] As an acidic catalyst to promote the equilibration reaction, a strong acid is preferred, and there is no particular limit to the type, but sulfuric acid, methanesulfonic acid, trifluoromethanesulfonic acid, etc. can be suitably used, and cation exchange resins having exchange groups of these acids are particularly preferred due to the ease of post-treatment. Furthermore, the amount of acidic catalyst added is preferably 100 to 10,000 ppm, and more preferably 500 to 3,000 ppm, relative to the total mass of the organopolysiloxane represented by formula (I') and the disiloxane compound represented by formula (IV).

[0058] Furthermore, during the equilibration reaction, water may be added to promote the hydrolysis condensation reaction between the organopolysiloxane represented by formula (I') and the disiloxane compound represented by 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 corresponding to the desired reaction rate is preferred. From the viewpoint of ensuring storage stability by reducing the highly active alkoxy groups at the organopolysiloxane terminus, the reaction rate of the alkoxy groups is preferably 50-100%, and more preferably 60-100%.

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

[0060] In the above equation (V), R 7 The monovalent aliphatic unsaturated hydrocarbon group having 2 to 8 carbon atoms is preferably one having 2 to 6 carbon atoms. Specific examples include alkenyl groups such as vinyl, allyl, 3-butenyl, 5-hexenyl, and 7-octenyl groups, with vinyl and allyl groups being preferred, and allyl groups being more preferred.

[0061] Considering compatibility with organopolysiloxanes, vinyl alcohol, allyl alcohol, and ethylene glycol monoallyl ether are preferred as compounds represented by the above formula (V), with ethylene glycol monoallyl ether being 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 above hydrosilylation reaction is preferably carried out in the presence of a catalyst. As the hydrosilylation reaction catalyst, compounds containing platinum group metals such as platinum, rhodium, and palladium can be used. Among these, compounds containing platinum are preferred, and examples include platinum black, chloroplatinic acid, alcohol-modified chloroplatinic acid, complexes of chloroplatinic acid with olefins, vinylsiloxanes, acetylene alcohol, etc., platinum carbonyl vinyl methyl complex, platinum-divinyltetramethyldisiloxane complex, platinum-cyclovinylmethylsiloxane complex, and platinum-octylaldehyde / octanol complex. The amount added should be a so-called catalytic amount that can promote the addition reaction, and is usually 0.1 to 500 ppm, preferably 1 to 200 ppm, in terms of the mass of the platinum group metal relative to the mass of the compound represented by formula (V) above.

[0064] There are no particular restrictions on the conditions for the hydrosilylation reaction, 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. A weight-average molecular weight of 1,000 or more provides better storage stability and flexural resistance, while a weight-average molecular weight of 500,000 or less eliminates the risk of unevenness or uneven coating during painting. Furthermore, the measurement conditions for GPC can be, for example, the method used in the later examples.

[0066] The kinematic viscosity of component (C) at 25°C is 5 to 2,000 mm². 2 / s is preferred, and 20-1,000 mm 2 / s is preferable. 5mm2 If the value is 2,000 mm or higher, it offers superior storage stability and bending resistance. 2 If the kinematic viscosity is less than / s, there is no risk of unevenness or unevenness in the paint finish during application. Kinematic viscosity can be measured using, for example, a Cannon-Fenske viscometer.

[0067] (C) The amount of alkoxy groups in component C is preferably 0.5 to 10% by mass relative to the organopolysiloxane, from the viewpoint of storage stability and adhesion to the substrate.

[0068] The amount of hydroxyl groups contained in component (C) is not particularly limited, but from the viewpoint of the viscosity of component (C), as well as the crosslinking density, chemical resistance, antifouling properties, and weather resistance of the resulting cured film, a hydroxyl value of 50 to 500 mg KOH / g is preferred, and 70 to 300 mg KOH / g is more preferred.

[0069] The amount of component (C) is 5 to 500 parts by mass of nonvolatile content per 100 parts by mass of nonvolatile content of component (A), preferably 5 to 100 parts by mass, and more preferably 5 to 50 parts by mass. If the amount of component (C) is less than the above range, the weather resistance and stain resistance of the resulting cured film will be insufficient, while if it is too much, the chemical resistance, hardness, and weather resistance will be insufficient. Furthermore, component (C) may be a single composition or a mixture of multiple compounds with 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 that is commonly used in organosiloxane-based coatings, but organometallic compounds are preferred, such as metal alkoxide compounds of Ti, Al, Zr, Sn, etc., metal chelate compounds, metal ester compounds, etc., but those containing organotin compounds are preferred.

[0071] Specific examples of metal alkoxide compounds 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; and 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 include titanium alkoxides such as tetraisooctyl titanate and tetra-n-lauryl titanate; zirconium 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, and tetra-n-stearyl zirconate; and dibutyltin dibutoxide.

[0072] Specific examples of metal chelating compounds include tris(ethylacetacetate)aluminum, tris(n-propylacetate)aluminum, tris(isopropylacetate)aluminum, tris(n-butylacetate)aluminum, isopropoxybis(ethylacetate)aluminum, tris(acetylacetonato)aluminum, tris(propionylacetonato)aluminum, diisopropoxypropionylacetonatoaluminum, acetylacetonato-bis(propionylacetonato)aluminum, monoethylacetate-bis(acetylacetonato)aluminum, acetylacetonatoaluminum-di-s-butyrate, methylacetoacetatealuminum-di-s-butyrate, di(methylacetoacetate)aluminum-mono-tert-butyrate, diisopropoxyethylacetoacetatealuminum, and monoacetyl Examples of 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 ester compounds such as dibutyltin diacetate, dibutyltin di(2-ethylhexylate), dibenzyltin di(2-ethylhexylate), dibutyltin dilaurate, dibutyltin diisooctylmaleate, and dibutyltin bis(acetylacetonate). However, using tin chelate compounds is suitable in terms of the chemical resistance of the resulting coating film.

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

[0074] When component (D) is included, the amount included should be sufficient to cure the composition, but usually 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). Furthermore, the curing catalyst of component (D) may be used alone or in combination of two or more types.

[0075] (5) Optional ingredients The coating composition of the present invention may contain any additives as appropriate, as long as they do not impair the effects of the present invention. Specific examples of 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 modifiers, reactive diluents, non-reactive diluents, surfactants, dispersants, defoamers, dehydrators, antioxidants, antioxidants, antistatic agents, infrared absorbers, ultraviolet absorbers, light stabilizers, fluorescent agents, dyes, pigments, fragrances, abrasives, rust inhibitors, thixotropy promoters, and the like. These can be used individually or in combination of two or more types.

[0076] Examples of solvents 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 individually or in combination of two or more. If the paint composition of the present invention contains a solvent, its content is preferably 1 to 50 parts by mass, and more preferably 5 to 20 parts by mass, based on 100 parts by mass of the total nonvolatile content of components (A) to (C).

[0077] Pigments include, for example, titanium dioxide, red iron oxide, cyanine-based coloring pigments, carbon black, zircon powder, silica, barium powder, precipitated barium sulfate, barium carbonate, calcium carbonate, gypsum, clay, white carbon, diatomaceous earth, talc, magnesium carbonate, alumina white, gloss white. To etc. Extender pigments include zinc phosphate, zinc phosphate-silicate, zinc aluminum phosphate, zinc calcium phosphate, calcium phosphate, aluminum pyrophosphate, calcium pyrophosphate, aluminum dihydrogen tripolyphosphate, aluminum metaphosphate, calcium metaphosphate, zinc oxide, zinc phosphate-molybdate, aluminum phosphate-molybdate, zinc, zinc oxide, zinc molybdate, calcium molybdate, borate compounds, barium metaborate, zinc cyanamide calcium, calcium silicate, calcium metasilicate; modified silica obtained by bonding cations such as calcium, zinc, cobalt, lead, strontium, and barium to porous silica particles; ion-exchange silica obtained by bonding cations by ion exchange; rust-preventive pigments such as aluminum pyrophosphate, vanadium pentoxide, calcium vanadate, and ammonium metavanadate, which may be used individually or in combination of two or more.

[0078] If the paint composition of the present invention contains a pigment, the amount of the pigment is preferably 5 to 100 parts by mass, and more preferably 30 to 90 parts by mass, based on the total nonvolatile content of components (A) to (C), with respect to the weather resistance of the formed coating film.

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

[0080] The viscosity of the paint composition of the present invention is not particularly limited, but considering the need to improve moldability or application workability and suppress the occurrence of unevenness, the viscosity at 25°C measured by a rotational viscometer is preferably 100,000 mPa·s or less, and more preferably 20,000 mPa·s or less. The lower limit of viscosity is not particularly limited, but is preferably 10 mPa·s or more.

[0081] (7) Cured films and coated articles of paint compositions A cured film and a coated article are obtained by applying the coating composition of the present invention to an object to be coated and curing it. There are no restrictions on the application method; for example, known methods such as spray application, roller application, brush application, and pour application can be used. The coating composition of the present invention can be cured at room temperature, but heating may be performed as needed to accelerate curing. The heating temperature is preferably 40 to 150°C, which allows the formed cured coating film to exhibit excellent weather resistance, chemical resistance, and stain resistance.

[0082] Examples of materials to be coated include glass and, if desired, pre-treated metal materials such as steel plates, galvanized steel plates, stainless steel, and aluminum; alkaline substrates such as concrete, mortar, slate, and slate tiles; ceramic building materials; plastics; and materials on which old paint films have been formed.

[0083] The paint composition of the present invention is not particularly limited in its applications, but examples include heavy-duty corrosion protection coatings for steel structures such as bridges, power transmission towers, plants, and tanks.

[0084] The paint composition of the present invention exhibits excellent long-term weather resistance and, on its own, provides a cured film that protects the coated object from harsh environments and maintains its aesthetic appearance. However, layers of known primers and / or intermediate coats may be provided as needed.

[0085] Examples of the above-mentioned primers include epoxy resin paints, modified epoxy resin paints, epoxy resin-based glass flake paints, epoxy resin coating materials, ultra-thick film epoxy resin paints, epoxy resin zinc-rich paints, inorganic zinc-rich paints, chlorinated rubber resin paints, phthalic acid resin paints, and epoxy ester resin paints. Examples of intermediate coats include epoxy resin paints, polyurethane paints, epoxy resin MIO paints, phenolic resin MIO paints, chlorinated rubber resin paints, and phthalic acid resin paints. [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 was measured at 25°C using a Cannon-Fenske viscometer, the hydroxyl value was measured by neutralization titration in accordance with JIS K 1557-1:2007, the isocyanate content is expressed as the mass fraction of isocyanate groups present in the sample in accordance with JIS K 1603-1:2007, and the average composition of organopolysiloxane was measured using an NMR analyzer manufactured by JEOL Ltd. 1 H-NMR and 29 The values ​​are calculated from the integrated values ​​of the Si-NMR spectrum, and the weight-average molecular weight (Mw) is the polystyrene equivalent value obtained by GPC (gel permeation chromatography) measurement under the following conditions. [GPC conditions] Equipment: HLC-8220 (manufactured by Tosoh Corporation) Columns: TSKgel GMHXL-L, TSKgel G4000HXL, TSKgel G2000HXL ×2 Developing solvent: Tetrahydrofuran (THF) Flow rate: 1mL / min Detector: RI Column constant temperature bath temperature: 40℃ Standard material: Polystyrene

[0087] [1] Synthesis of hydroxyl group-containing organopolysiloxanes A hydroxyl group-containing organopolysiloxane was manufactured using the following organopolysiloxanes as raw materials. <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 a methyl group (weight-average molecular weight 1,500, kinematic 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 a methyl group (weight-average molecular weight 1,800, kinematic viscosity 70 mmHg) 2 / s)

[0088] [Synthesis Example 1-1] A 500 mL separable flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer contains organopolysiloxane. 1 100 parts by mass of [the substance], 55 parts by mass of tetramethyldisiloxane, 35 parts by mass of methanol, and 2 parts by mass of strongly acidic cation exchange resin (Lankusses Levatit K2629) were added, and 11 parts by mass of water were added dropwise while stirring. After stirring at 25°C for 3 hours, the resulting reaction solution was filtered. Next, the fraction was removed by vacuum distillation (90°C, 1.3 kPa). 1 H-NMR and 29 The reaction rate of the Si-OCH3 group, calculated from the integrated value of the detection spectrum in Si-NMR, was 80%. Furthermore, 0.1 parts by mass of a Pt(0) 1,3-divinyltetramethyldisiloxane complex and 64 parts by mass of ethylene glycol monoallyl ether were added, and the mixture was heated at 80°C for 4 hours. After that, unreacted ethylene glycol monoallyl ether was removed by vacuum distillation (90°C, 1.3 kPa) to obtain hydroxyl group-containing organopolysiloxane (C-1) (yield 150 parts by mass).

[0089] [Synthesis Example 1-2] Hydroxyl group-containing organopolysiloxane (C-2) was obtained by the same formulation as in Synthesis Example 1-1, except that organopolysiloxane 1, a raw material, 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 obtained organopolysiloxanes are shown in Table 1.

[0091] [Table 1]

[0092] [2] Preparation of paint 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 produce curable compositions (i) to (xii). <(A) component> (A-1): Acrydic A-801P (Toluene-butyl acetate solution of acrylic polyol, 50% by mass of non-volatile content, 50 mg KOH / g hydroxyl value, manufactured by DIC Corporation) (A-2): Barnock D-220 (polyester polyol, 100% by mass of non-volatile content, hydroxyl value 147 mg KOH / g, manufactured by DIC Corporation) <(B) component> (B-1): Barnock DN-901S (Polyisocyanate, 100% by mass of non-volatile content, 23.1% by mass of isocyanate content, manufactured by DIC Corporation) (B-2): Duranate TPA-100 (polyisocyanate, 100% by mass of non-volatile content, 23.2% by mass of isocyanate content, manufactured by Asahi Kasei Corporation) <(C) component> (C-1) Hydroxyl group-containing organopolysiloxane obtained in the above synthesis example 1-1 (C-2) Hydroxyl group-containing organopolysiloxane obtained in the above synthesis examples 1-2 <(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 to a metal substrate by flow coating to a dry film thickness of 30 μm, and the films were cured for 7 days under conditions of 23°C and 50% RH to obtain the coatings. The obtained coated articles were evaluated for coating appearance, rubbing, stain resistance, and accelerated weathering. The results are shown in Table 3. (1) Appearance of the coating Visually, a coating surface that was uniform and free from unevenness or cracks caused by aggregates was marked with a circle (○), while a coating surface that was uneven and showed whitening, unevenness or cracks caused by aggregates was marked with a cross (×). (2) Rubbing test Acetone in Bencot M-3II (area 4cm²) 2 The samples were immersed in a solution (manufactured by Asahi Kasei Corporation), and the surface was rubbed back and forth 30 times under a load of 500 gf. The appearance of the coating film was then visually evaluated. Samples that showed no change in appearance after the rubbing test compared to the appearance before the test were marked with ○, while those showing peeling or whitening of the coating film were marked with ×. (3) Stain resistance test On the test surface, draw lines with an oil-based marker (organic solvent type marker, product name: Macki Extra Fine, manufactured by Zebra Co., Ltd.), leave for 3 hours, then soak Benkot M-3II (area 4cm²) in a mixed solvent of ethanol:toluene (mass ratio 1:1). 2 The test evaluated whether the ink could be wiped off using a product manufactured by Asahi Kasei Corporation. After the test, the amount of ink remaining on the coating was visually observed and evaluated in two stages. ○: No significant changes are observed compared to the current test specimen. ×: Ink remains compared to the current test piece. (4) Accelerated weather resistance The accelerated weathering test was performed using an ultra-accelerated weathering tester (iSuper UV Tester, manufactured by Iwasaki Electric Co., Ltd.). Polyester-coated steel sheets (0.8 mm x 70 mm x 60 mm) were used as test specimens. The test conditions consisted of 8 hours of irradiation (UV irradiation intensity 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 16 hours forming one cycle, and 30 cycles were performed. After the test, the blistering, cracking, peeling, and gloss changes of the coating film were observed visually and evaluated in two stages. ○: No significant changes are observed compared to the current test specimen. ×: Compared to the current test specimen, there is loss of gloss, cracking, and peeling.

[0095] [Table 3]

[0096] As shown in Table 2, the cured films obtained in Examples 2-1 to 2-8 exhibit excellent appearance, solvent resistance, and also possess superior stain resistance and weather resistance. On the other hand, cured films obtained from curable compositions lacking component (C) and curable compositions with insufficient amounts of component (C) (Comparative Examples 2-1 and 2-2) showed excellent appearance and solvent resistance, but did not exhibit the antifouling and weather resistance characteristic of silicone. Furthermore, the cured film of Comparative Example 2-3, with an NCO / OH ratio less than 0.8, showed insufficient crosslinking and inferior solvent resistance and weather resistance. In addition, the cured film of Comparative Example 2-4, with an NCO / OH ratio greater than 1.4, exhibited some whitening in appearance and inferior antifouling and weather resistance.

Claims

1. (A) One or more polyols selected from the group consisting of acrylic polyols, polyester polyols, and polyether polyols, (B) Compounds having two or more isocyanate groups in one molecule, and (C) Hydroxyl group-containing organopolysiloxane represented by the following formula (I): 5 to 500 parts by mass per 100 parts by mass of component (A) 【Chemistry 1】 (In the formula, R 1 Each of these is independently 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 hydrogen atom or a halogen atom. 2 R is a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, or an i-propyl group. 3 The base is represented by the following formula (II), where 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. 【Chemistry 2】 (In the formula, R 4 Each of these is independently 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 hydrogen atom or a halogen atom. 5 Each of these is 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. Includes, 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) (NCO (B) / OH (A+C) A paint composition in which the ratio is 0.8 to 1.

4.

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

3. The paint composition according to claim 1, wherein component (B) is a polyisocyanate having two or more isocyanate groups in one molecule and not having a silicon atom.

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

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

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

7. The paint composition according to claim 1, wherein in formula (I), b is a number satisfying 0.5 ≤ b ≤ 1.

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

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

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

11. Furthermore, the paint composition according to claim 1, further comprising (D) a curing catalyst.

12. A method for producing a paint composition according to any one of claims 1 to 11, comprising mixing the components (A) to (C) at 10 to 40°C.

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

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

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