JP7809935B2 - Resin composition, coating agent, and article - Google Patents

Description

The present invention relates to a resin composition, a coating agent, and an article having a cured coating film of the coating agent.

In recent years, the development of high-performance materials that combine the properties of both inorganic and organic materials has been widely underway in various industrial fields. It is generally known that inorganic materials have excellent durability, including weather resistance, heat resistance, and scratch resistance, while organic materials are highly flexible and easy to process. In this context, resin materials that combine inorganic and organic materials have been proposed (see, for example, Patent Document 1).

Meanwhile, antibacterial processing has long been used to impart functionality to clothing, daily necessities, interior materials, and the like. However, in recent years, the spread of coronaviruses and influenza viruses has led to growing interest in imparting antiviral properties. Conventional antiviral agents include silver-based compounds and ammonium salts. However, silver-based compounds only have antiviral properties against a limited number of virus types, and ammonium salts have the problem of low safety. For these reasons, there is a strong demand for materials that have excellent durability, such as weather resistance, and antiviral properties that are practically usable, but the reality is that such materials have not yet been discovered.

Japanese Patent Application Publication No. 11-279408

The problem that the present invention aims to solve is to provide a resin composition that can form a coating film that has excellent weather resistance and antiviral properties.

The present invention provides a resin composition characterized by containing a composite resin (ABC) in which the polysiloxane segment (B) of the composite resin (AB) is chemically bonded to a polymer segment (A) and a polysiloxane segment (B), and a polysiloxane segment (C) derived from a condensate (c) of an alkyltrialkoxysilane in which the alkyl group has 1 to 3 carbon atoms is bonded via a silicon-oxygen bond, and a visible light-responsive photocatalyst (D).

The present invention also provides a coating agent containing the resin composition, and an article having a cured coating film of the coating agent.

The resin composition of the present invention can form a coating film that has excellent antiviral properties while maintaining excellent weather resistance. Therefore, the resin composition of the present invention can be suitably used as a coating agent for construction components such as exterior walls, roofs, and membrane structures; civil engineering components such as guardrails, soundproof walls, and drainage ditches; metal substrates such as zinc-plated steel sheets and aluminum-zinc alloy steel sheets used in home appliances, industrial machinery, and automobile parts; aluminum sheets, aluminum alloy sheets, electromagnetic steel sheets, copper sheets, and stainless steel sheets; plastic products such as mobile phones, home appliances, office automation equipment, and automobile interior materials; and fabrics.

The resin composition of the present invention contains a composite resin (ABC) in which the polysiloxane segment (B) of the composite resin (AB) is chemically bonded to a polymer segment (A) and a polysiloxane segment (B), and a polysiloxane segment (C) derived from a condensate (c) of an alkyltrialkoxysilane in which the alkyl group has 1 to 3 carbon atoms is bonded via a silicon-oxygen bond; and a visible light-responsive photocatalyst (D).

First, the composite resin (ABC) will be described. The composite resin (ABC) is a composite resin (AB) in which a polymer segment (A) and a polysiloxane segment (B) are chemically bonded together, and the polysiloxane segment (B) is bonded to a polysiloxane segment (C) derived from a condensate (c) of an alkyltrialkoxysilane in which the alkyl group has 1 to 3 carbon atoms via a silicon-oxygen bond.

Examples of the composite resin (ABC) include a composite resin having a graft structure in which a polysiloxane segment (B) is chemically bonded to the side chain of a polymer segment (A), and a composite resin having a structure in which a polysiloxane segment (B) of a composite resin having a block structure in which a polysiloxane segment (B) is chemically bonded to the end of the polymer segment (A), and a polysiloxane segment (C) derived from a condensate (c) of an alkyltrialkoxysilane in which the alkyl group has 1 to 3 carbon atoms is chemically bonded via a silicon-oxygen bond.

The chemical bond between the polymer segment (A) and the polysiloxane segment (B) in the composite resin (ABC) can be, for example, a bond represented by the following general formula (3) or (4). Of these, the use of a composite resin having the bond represented by general formula (3) is preferred because it allows the formation of a coating film with excellent weather resistance.

(The carbon atom in general formula (3) constitutes a part of the polymer segment (A), and the silicon atom and oxygen atom constitute a part of the polysiloxane segment (B).)

(The carbon atom in general formula (4) constitutes a part of the polymer segment (A), and the silicon atom and oxygen atom constitute a part of the polysiloxane segment (B).)

The polymer segment (A) is preferably derived from a polymer having silicon-bonded hydroxyl groups and/or silicon-bonded hydrolyzable groups (hereinafter abbreviated as "silicon-bonded hydroxyl groups and/or hydrolyzable groups"), since these groups readily undergo hydrolytic condensation with silicon-bonded hydroxyl groups or silicon-bonded hydrolyzable groups contained in the polysiloxane segment (B) or its synthetic raw materials, forming a chemical bond in the bonding pattern of general formula (3). The structure other than the hydrolyzable groups in the polymer may be any polymer other than polysiloxane. Examples of such polymers include vinyl-based polymers such as acrylic polymers, fluoroolefin polymers, vinyl ester polymers, aromatic vinyl polymers, and polyolefin polymers, polyester polymers, and polyether polymers. Among these, vinyl-based polymers are preferred, and acrylic polymers are more preferred, as they provide superior weather resistance.

The hydrolyzable group bonded to a silicon atom in the polymer may be any functional group that can be hydrolyzed to produce a hydroxyl group (silanol group) bonded to a silicon atom. Examples include a halogen atom bonded to a silicon atom, an alkoxy group bonded to a silicon atom, an acyloxy group bonded to a silicon atom, a phenoxy group bonded to a silicon atom, a mercapto group bonded to a silicon atom, an amino group bonded to a silicon atom, an amido group bonded to a silicon atom, an aminooxy group bonded to a silicon atom, an iminoxy group bonded to a silicon atom, and an alkenyloxy group bonded to a silicon atom. Of these, an alkoxy group bonded to a silicon atom is preferred because it facilitates the hydrolysis reaction and allows for easy removal of by-products after the reaction.

Furthermore, the polymer preferably contains an acid group, such as a carboxyl group, a phosphoric acid group, an acidic phosphate ester group, a phosphorous acid group, a sulfonic acid group, or a sulfinic acid group, as this provides even better weather resistance. Of these, a carboxyl group is preferred because it is easily introduced into the skeleton of the composite resin (ABC).

The resin composition of the present invention preferably uses an aqueous medium, and when preparing an aqueous resin composition, it is preferable to neutralize the acid groups. Examples of basic compounds that can be used during neutralization include organic amine compounds such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, 2-aminoethanol, and 2-dimethylaminoethanol; inorganic basic compounds such as ammonia, sodium hydroxide, and potassium hydroxide; and quaternary ammonium hydroxides such as tetramethylammonium hydroxide, tetra-n-butylammonium hydroxide, and trimethylbenzylammonium hydroxide. Among these, organic amine compounds and ammonia (aqueous ammonia) are preferably used.

From the viewpoint of maintaining good storage stability of an aqueous dispersion or aqueous solution in which the composite resin (ABC) is dispersed or dissolved in an aqueous medium, the amount of the acid groups is preferably 0.1 to 20 parts by mass, and more preferably 0.2 to 10 parts by mass, per 100 parts by mass of the composite resin (ABC).

The polymer segment (A) may contain functional groups other than those described above. Examples of such functional groups include a hydroxyl group, a blocked hydroxyl group, a cyclocarbonate group, an epoxy group, a carbonyl group, a primary amide group, a secondary amide group, a carbamate group, a polyethylene glycol group, a polypropylene glycol group, and a group represented by the following general formula (5):

The polysiloxane segment (B) constituting the composite resin (ABC) can be, for example, a segment derived from a polysiloxane having a silicon-bonded hydroxyl group and/or a hydrolyzable group. Examples of the hydrolyzable group bonded to the silicon atom include the same hydrolyzable groups bonded to the silicon atom as those described for the polymer segment (A), and the preferred examples are also the same.

The polysiloxane segment (B) preferably has a structure represented by the following general formula (1) or (2). The polysiloxane segment having the structure represented by the following general formula (1) or (2) has a three-dimensional network-like polysiloxane structure, and therefore the resulting coating film has excellent solvent resistance, weather resistance, and other properties.

(In general formulas (1) and (2), ^R1 is an organic group bonded to a silicon atom and having 4 to 12 carbon atoms, and ^R2 and ^R3 are each independently a methyl group bonded to a silicon atom or an ethyl group bonded to a silicon atom. ^R1 is preferably a hydrocarbon group bonded to a silicon atom and having 4 to 12 carbon atoms, and more preferably a phenyl group or an alkyl group having 4 carbon atoms. ^R2 and ^R3 are both preferably a methyl group bonded to a silicon atom or an ethyl group bonded to a silicon atom, and more preferably both are methyl groups bonded to a silicon atom.)

Examples of polysiloxane segments having the structure represented by general formula (1) or (2) include segments derived from polysiloxanes obtained by hydrolytic condensation of organoalkoxysilanes, preferably monoorganotrialkoxysilanes having a silicon-bonded organic group containing 4 to 12 carbon atoms (hereinafter abbreviated as "silicon-bonded organic group containing 4 to 12 carbon atoms"), and/or diorganodialkoxysilanes having two silicon-bonded methyl groups and/or two silicon-bonded ethyl groups (hereinafter abbreviated as "silicon-bonded methyl groups and/or ethyl groups"). These polysiloxane segments have a silicon-bonded organic group containing 4 to 12 carbon atoms and a silicon-bonded hydroxyl group and/or hydrolyzable group, and/or two silicon-bonded methyl groups and/or ethyl groups and a silicon-bonded hydroxyl group and/or hydrolyzable group, and may have a linear, branched, or cyclic structure.

Examples of the silicon-bonded organic group having 4 to 12 carbon atoms include alkyl groups, cycloalkyl groups, aryl groups, and aralkyl groups, all of which have 4 to 12 carbon atoms bonded to a silicon atom. These organic groups may also have a substituent.

Such silicon-bonded organic groups having 4 to 12 carbon atoms are preferably hydrocarbon groups bonded to silicon atoms, such as alkyl groups such as n-butyl, isobutyl, n-hexyl, n-octyl, n-dodecyl, and cyclohexylmethyl, all of which are bonded to silicon atoms; cycloalkyl groups such as cyclohexyl and 4-methylcyclohexyl; aryl groups such as phenyl and 4-methylphenyl; and aralkyl groups such as benzyl. Of these, silicon-bonded phenyl groups and silicon-bonded alkyl groups having 4 carbon atoms are more preferred.

The polysiloxane segment (C) constituting the composite resin (ABC) is a segment derived from a condensate (c) of an alkyltrialkoxysilane in which the alkyl group has 1 to 3 carbon atoms. The condensate (c) of an alkyltrialkoxysilane in which the alkyl group has 1 to 3 carbon atoms used here has a hydroxyl group bonded to a silicon atom and/or an alkoxy group bonded to a silicon atom.

The alkyltrialkoxysilane condensate (c) preferably has a structure represented by the following general formula (6): The polysiloxane segment derived from the alkyltrialkoxysilane condensate having the structure represented by the following general formula (6) has a three-dimensional network polysiloxane structure, and therefore the resulting coating film has excellent solvent resistance, weather resistance, etc.

(However, ^R4 in general formula (6) is an alkyl group having 1 to 3 carbon atoms.)

The composite resin (ABC) preferably has a total amount (B+C) of the polysiloxane segment (B) and the polysiloxane segment (C) derived from the condensate (c) of alkyltrialkoxysilane, in the range of 15 to 85 parts by mass, and more preferably 25 to 65 parts by mass, per 100 parts by mass of the composite resin (ABC), in order to further improve weather resistance, stain resistance, and substrate conformability.

Furthermore, in the composite resin (ABC), the amount of the polysiloxane segment (C) derived from the alkyltrialkoxysilane condensate (c) is preferably in the range of 10 to 60 parts by mass, more preferably 20 to 50 parts by mass, per 100 parts by mass of the composite resin (ABC), because this further improves weather resistance, contamination resistance, and substrate conformability.

The composite resin (ABC) can be produced by various methods, but it is preferable to produce it by a process consisting of the following production steps (I) and (II).

In production process (I), the polymer having silicon-bonded hydroxyl groups and/or hydrolyzable groups is subjected to hydrolysis and condensation with organoalkoxysilane (b) and/or its hydrolysis condensate (b-1) to obtain a composite resin (AB) in which the polymer is chemically bonded to polysiloxane segments (B) derived from organoalkoxysilane (b).

In the manufacturing process (II), the obtained composite resin (AB) is subjected to hydrolysis and condensation with a condensate (c) of an alkyltrialkoxysilane having an alkyl group with 1 to 3 carbon atoms to obtain a composite resin (ABC) in which the polysiloxane segment (B) of the composite resin (AB) is bonded to the polysiloxane segment (C) derived from the condensate (c) of an alkyltrialkoxysilane having 1 to 3 carbon atoms via a silicon-oxygen bond, and further, if necessary, the acid groups in the composite resin (ABC) are converted into salts. A step of neutralizing the resulting composite resin (AB) with a basic compound, or, if the resulting composite resin (AB) contains acid groups, a step of neutralizing the resulting composite resin (AB) with a basic compound, and then hydrolyzing and condensing a condensate (c) of an alkyltrialkoxysilane having an alkyl group with 1 to 3 carbon atoms to obtain a composite resin (ABC) in which the polysiloxane segment (B) of the composite resin (AB) and the polysiloxane segment (C) derived from the condensate (c) of an alkyltrialkoxysilane having an alkyl group with 1 to 3 carbon atoms are bonded via a silicon-oxygen bond.

The hydrolysis condensation reaction in the above-mentioned manufacturing process can be carried out using a variety of methods, but a simple and preferred method is to carry out the reaction by supplying water and a catalyst during the manufacturing process.

The hydrolysis condensation reaction refers to a reaction in which some of the hydrolyzable groups are hydrolyzed by the influence of water or the like to form hydroxyl groups, and a condensation reaction then occurs between the hydroxyl groups and the hydrolyzable groups.

Specific raw materials for the polymer constituting the polymer segment (A) include, for example, a silicon-bonded hydroxyl group-containing vinyl monomer and/or a silicon-bonded hydrolyzable group-containing vinyl monomer, and, if necessary, other vinyl monomers and acid group-containing vinyl monomers, and the polymer segment (A) can be produced by polymerizing these by known methods.

Examples of the hydroxyl group-containing vinyl monomer bonded to a silicon atom include trihydroxyvinylsilane, ethoxydihydroxyvinylsilane, diethoxyhydroxyvinylsilane, dichlorohydroxyvinylsilane, 3-(meth)acryloyloxypropyltrihydroxysilane, and 3-(meth)acryloyloxypropylmethyldihydroxysilane.

As the vinyl monomer containing a hydrolyzable group bonded to a silicon atom, for example, a vinyl monomer having a hydrolyzable group represented by the following general formula (7) can be used.

(In general formula (7), ^R5 is a monovalent organic group such as an alkyl group, an aryl group, or an aralkyl group; ^R6 is a halogen atom, an alkoxy group, an acyloxy group, a phenoxy group, an aryloxy group, a mercapto group, an amino group, an amido group, an aminooxy group, an iminoxy group, or an alkenyloxy group; and n is an integer of 0 to 2.)

Examples of vinyl monomers having a hydrolyzable group represented by the general formula (7) include vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, vinyltri(2-methoxyethoxy)silane, vinyltriacetoxysilane, vinyltrichlorosilane, 2-trimethoxysilylethyl vinyl ether, 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropyltriethoxysilane, 3-(meth)acryloyloxypropylmethyldimethoxysilane, and 3-(meth)acryloyloxypropyltrichlorosilane. Among these, vinyltrimethoxysilane and 3-(meth)acryloyloxypropyltrimethoxysilane are preferred because they facilitate the hydrolysis reaction and allow for the easy removal of by-products after the reaction.

Examples of the other vinyl monomers include 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, 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 vinyl acetate. vinyl carboxylate esters such as 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; tertiary amide group-containing monomers such as N,N-dimethyl(meth)acrylamide, N-(meth)acryloylmorpholine, N-(meth)acryloylpyrrolidine, and N-vinylpyrrolidone;

Hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; hydroxyl group-containing vinyl ethers such as 2-hydroxyethyl vinyl ether and 4-hydroxybutyl vinyl ether; hydroxyl group-containing allyl ethers such as 2-hydroxyethyl allyl ether and 2-hydroxybutyl allyl ether; addition reaction products of these vinyl monomers containing a hydroxyl group bonded to a carbon atom with lactones such as ε-caprolactone;

Tertiary amino group-containing (meth)acrylic acid esters such as 2-dimethylaminoethyl (meth)acrylate, 2-diethylaminoethyl (meth)acrylate, 2-di-n-propylaminoethyl (meth)acrylate, 3-dimethylaminopropyl (meth)acrylate, 4-dimethylaminobutyl (meth)acrylate, and N-[2-(meth)acryloyloxy]ethylmorpholine; tertiary amino group-containing aromatic vinyl monomers such as vinylpyridine, N-vinylcarbazole, and N-vinylquinoline; N-(2-dimethylamino)ethyl (meth) Examples include tertiary amino group-containing (meth)acrylamides such as acrylamide, N-(2-diethylamino)ethyl (meth)acrylamide, and N-(2-di-n-propylamino)ethyl (meth)acrylamide; tertiary amino group-containing crotonic acid amides such as N-(2-dimethylamino)ethyl crotonic acid amide and N-(4-dimethylamino)butyl crotonic acid amide; and tertiary amino group-containing vinyl ethers such as 2-dimethylaminoethyl vinyl ether, 2-diethylaminoethyl vinyl ether, and 4-dimethylaminobutyl vinyl ether.

The type and amount of the other vinyl monomer can be appropriately selected depending on the properties to be imparted to the aqueous resin composition of the present invention, as long as the effects of the present invention are not impaired. As the other vinyl monomer, one or more selected from the group consisting of methyl (meth)acrylate, n-butyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, and cyclohexyl (meth)acrylate are preferred, as they provide even better weather resistance.

Examples of the acid group-containing vinyl monomer include various vinyl monomers containing acid groups such as carboxyl groups, phosphoric acid groups, acidic phosphate ester groups, phosphorous acid groups, sulfonic acid groups, and sulfinic acid groups, but among these, vinyl monomers containing carboxyl groups (which may also be carboxylic acid anhydride groups) are preferred.

Examples of the carboxyl group-containing vinyl monomer include unsaturated carboxylic acids such as (meth)acrylic acid, 2-carboxyethyl (meth)acrylate, crotonic acid, itaconic acid, maleic acid, and fumaric acid; unsaturated polycarboxylic acid anhydrides such as maleic anhydride and itaconic anhydride; unsaturated monocarboxylic acid anhydrides such as acrylic anhydride and methacrylic anhydride; mixed acid anhydrides of unsaturated carboxylic acids such as acrylic acid and methacrylic acid with saturated carboxylic acids such as acetic acid, propionic acid, and benzoic acid; monomethyl itaconate, mono-n-butyl itaconate, monomethyl maleate, mono-n-butyl maleate, and monomethyl fumarate; Examples include various monoesters (half esters) of saturated dicarboxylic acids such as mono-n-butyl fumarate with saturated monohydric alcohols; monovinyl esters of saturated dicarboxylic acids such as monovinyl adipate and monovinyl succinate; addition reaction products of saturated polycarboxylic acid anhydrides such as succinic anhydride, glutaric anhydride, phthalic anhydride, and trimellitic anhydride with vinyl monomers containing a hydroxyl group bonded to a carbon atom; and various monomers obtained by addition reaction of the above-mentioned carboxyl group-containing monomers with lactones. Of these, unsaturated carboxylic acids such as (meth)acrylic acid are preferred because they can be easily incorporated into vinyl polymers.

The carboxyl group may be blocked. Examples of vinyl monomers having such blocked carboxyl groups include silyl ester group-containing vinyl monomers such as trimethylsilyl (meth)acrylate, dimethyl-tert-butylsilyl (meth)acrylate, and trimethylsilyl crotonate; hemiacetal ester group- or hemiketal ester group-containing monomers such as 1-ethoxyethyl (meth)acrylate, 2-methoxy-2-(meth)acryloyloxypropane, and 2-(meth)acryloyloxytetrahydrofuran; and tert-butyl ester group-containing monomers such as tert-butyl (meth)acrylate and tert-butyl crotonate.

In addition, the polymer may further contain at least one hydrophilic group selected from the group consisting of anionic groups, cationic groups, and nonionic groups, in order to improve the solubility or dispersibility of the composite resin (ABC) in an aqueous medium.

The polymer can be produced by known methods such as radical polymerization. When polymerizing the vinyl monomer by radical polymerization, a polymerization initiator and an organic solvent can be used as needed. Examples of such polymerization initiators include azo compounds such as 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobis(2-methylbutyronitrile); and peroxides such as tert-butyl peroxypivalate, tert-butyl peroxybenzoate, tert-butylperoxy-2-ethylhexanoate, di-tert-butyl peroxide, cumene hydroperoxide, and diisopropyl peroxycarbonate.

Examples of the organic solvent include aliphatic or alicyclic hydrocarbons such as n-hexane, n-heptane, n-octane, cyclohexane, and cyclopentane; aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; alcohols such as methanol, ethanol, n-butanol, isopropyl alcohol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, and propylene glycol monopropyl ether; esters such as ethyl acetate, n-butyl acetate, n-amyl acetate, ethylene glycol monomethyl ether acetate, and propylene glycol monomethyl ether acetate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl n-amyl ketone, and cyclohexanone; polyalkylene glycol dialkyl ethers such as diethylene glycol dimethyl ether and diethylene glycol dibutyl ether; ethers such as 1,2-dimethoxyethane, tetrahydrofuran, and dioxane; N-methylpyrrolidone, dimethylformamide, dimethylacetamide, and ethylene carbonate. These may be used alone or in combination of two or more.

The polymer preferably has a number-average molecular weight in the range of 500 to 200,000, more preferably 700 to 100,000, and particularly preferably 1,000 to 50,000. Using a polymer with a number-average molecular weight within this range prevents thickening and gelation during the production of the composite resin (ABC), and allows for the formation of a coating film with excellent durability. The number-average molecular weight of the polymer is a value measured by gel permeation chromatography (GPC).

Next, we will describe the organoalkoxysilane (b) and/or its hydrolysis condensate (b-1) used to form the polysiloxane segment (B) in the production process (I).

The organoalkoxysilane (b) is not particularly limited, but among them, monoorganotrialkoxysilanes having an organic group with 4 to 12 carbon atoms and diorganodialkoxysilanes having two methyl groups and/or two ethyl groups are both preferred, as they can produce a composite resin (ABC) with excellent dispersion stability and form a coating film with excellent durability.

The hydrolysis condensate (b-1) of the organoalkoxysilane (b) is not particularly limited as long as it is obtained by hydrolysis condensation of the organoalkoxysilane (b). However, it is preferably obtained by hydrolysis condensation of a monoorganotrialkoxysilane having a silicon-bonded organic group having 4 to 12 carbon atoms, and/or a diorganodialkoxysilane having two silicon-bonded methyl groups and/or ethyl groups.

Examples of the monoorganotrialkoxysilane having a silicon-bonded organic group having 4 to 12 carbon atoms include iso-butyltrimethoxysilane, cyclohexyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3-(meth)acryloyloxypropyltrimethoxysilane, and 3-(meth)acryloyloxypropyltriethoxysilane.

Examples of diorganodialkoxysilanes having two silicon-bonded methyl and/or ethyl groups include dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldi-n-butoxysilane, dimethyldiacetoxysilane, diethyldimethoxysilane, and diethyldiacetoxysilane.

Of these organoalkoxysilanes (b), iso-butyltrimethoxysilane, phenyltrimethoxysilane, and dimethyldimethoxysilane are preferred because they facilitate the hydrolysis reaction and the by-products after the reaction can be easily removed. Furthermore, these organoalkoxysilanes (b) may be used alone or in combination of two or more types.

In the production process (I), it is entirely possible to use the hydrolysis condensation product (b-1) of organoalkoxysilane (b) alone. However, because the composite resin (A'B) can be easily produced by hydrolysis condensation, it is preferable to use organoalkoxysilane (b) alone or to use organoalkoxysilane (b) and its hydrolysis condensation product (b-1) in combination, with organoalkoxysilane (b) being particularly preferred. Here, the use of organoalkoxysilane (b) alone refers to the use of only organoalkoxysilane (b), and also includes the use of two or more types of organoalkoxysilane (b) in combination.

The hydrolysis condensation reaction in the production step (I) can be carried out by various methods, but a simple and preferred method is to carry out the reaction by supplying water and a catalyst during the production step (I).

Examples of the catalyst include inorganic acids such as hydrochloric acid, sulfuric acid, and phosphoric acid; organic acids such as p-toluenesulfonic acid, monoisopropyl phosphate, and acetic acid; inorganic bases such as sodium hydroxide and potassium hydroxide; titanate esters such as tetraisopropyl titanate and tetrabutyl titanate; 1,8-diazabicyclo[5.4.0]undecene-7 (DBU), 1,5-diazabicyclo[4.3.0]nonene-5 (DBN), 1,4-diazabicyclo[2.2.2]octane (DABCO), tri-n-butylamine, dimethylbenzylamine, monoethanolamine, and imidazole. Compounds containing a basic nitrogen atom such as ammonium nitrate and 1-methylimidazole; quaternary ammonium salts such as tetramethylammonium salt, tetrabutylammonium salt, and dilauryldimethylammonium salt, which have chloride, bromide, carboxylate, hydroxide, or the like as a counter anion; and tin carboxylates such as dibutyltin diacetate, dibutyltin dioctoate, dibutyltin dilaurate, dibutyltin diacetylacetonate, tin octoate, and tin stearate, which can be used alone or in combination of two or more.

The catalyst is preferably used in the range of 0.0001 to 10 parts by mass, more preferably 0.0005 to 3 parts by mass, and particularly preferably 0.001 to 1 part by mass, per 100 parts by mass of the organoalkoxysilane (b) and/or its hydrolysis condensate (b-1).

The amount of water used to carry out the hydrolysis and condensation reaction is suitably 0.05 moles or more, preferably 0.1 moles or more, and particularly preferably 0.5 to 3.0 moles per mole of hydrolyzable groups and hydroxyl groups contained in the organoalkoxysilane (b) and/or its hydrolysis and condensation product (b-1).

The catalyst and water may be supplied all at once or gradually, or a pre-mixture of the catalyst and water may be supplied.

The reaction temperature for the hydrolysis condensation reaction is suitably in the range of 0 to 150°C, and preferably in the range of 20 to 100°C. The reaction pressure can be any of normal pressure, elevated pressure, or reduced pressure.

The by-products alcohol and water that may be produced in the hydrolysis and condensation reaction may be removed by distillation or other methods if they reduce the stability of the resulting aqueous curable coating composition.

Next, we will describe in detail the condensate (c) of an alkyltrialkoxysilane in which the alkyl group has 1 to 3 carbon atoms, which is used to form the polysiloxane segment (C) in the production process (II).

Examples of alkyltrialkoxysilanes in which the alkyl group has 1 to 3 carbon atoms include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, and isopropyltrimethoxysilane. Of these, methyltrimethoxysilane and ethyltrimethoxysilane are preferred because they facilitate the hydrolysis reaction and allow the by-products to be easily removed after the reaction. These alkyltrialkoxysilanes may be used alone or in combination of two or more types.

There are no particular limitations on the method for obtaining the condensate (c) from the alkyltrialkoxysilane, and various methods can be used. However, a method in which the hydrolysis condensation reaction proceeds by supplying water and a catalyst is simple and preferred.

The water and catalyst used in this process can be used under the same conditions as those used in the hydrolysis condensation reaction in production step (I) above.

In addition, in the production process (II), in addition to the condensate (c) of an alkyltrialkoxysilane in which the alkyl group has 1 to 3 carbon atoms, other silane compounds or their hydrolysis condensates can be used in combination.

Examples of the other silane compounds include tetrafunctional alkoxysilane compounds such as tetramethoxysilane, tetraethoxysilane, and tetra-n-propoxysilane; hydrolysis condensates of the tetrafunctional alkoxysilane compounds; and the like. These can be used in combination as long as the effects of the present invention are not impaired.

When the tetrafunctional alkoxysilane compound or its hydrolysis condensate is used in combination, it is preferable that the silicon atoms contained in the tetrafunctional alkoxysilane compound or its hydrolysis condensate not exceed 20 mol % relative to 100 mol % of all silicon atoms constituting the polysiloxane segment (B) and polysiloxane segment (C).

Next, we will explain the visible light responsive photocatalyst (D).

The visible light responsive photocatalyst (D) is an essential component for achieving excellent antiviral properties and can also improve weather resistance. Examples of the visible light responsive photocatalyst (D) include compositions containing titanium oxide (a). Titanium oxide (a) supported with a metal compound is preferred, as it provides even better antiviral properties and weather resistance.

Examples of the titanium oxide (a) that can be used include rutile-type titanium oxide (a1), anatase-type titanium oxide, and brookite-type titanium oxide. These titanium oxides may be used alone or in combination of two or more. Among these, rutile-type titanium oxide (a1) is preferred because it has excellent photocatalytic activity in the visible light region.

The content (rutilated ratio) of the rutile-type titanium oxide (a1) is preferably 15 mol% or more, more preferably 50 mol% or more, and even more preferably 90 mol% or more, in order to obtain even better antiviral properties in bright and dark places, organic compound decomposition properties in bright places, visible light responsiveness, and weather resistance.

Generally known methods for producing titanium oxide (a) are the liquid phase method and the gas phase method. The liquid phase method involves hydrolyzing or neutralizing titanyl sulfate obtained from a solution in which raw ore such as ilmenite is dissolved to obtain titanium oxide. The gas phase method involves chlorinating raw ore such as rutile to obtain titanium oxide through a gas phase reaction between titanium tetrachloride, which is obtained from the chlorination of raw ore such as rutile, and oxygen. One way to distinguish between titanium oxides produced by these two methods is to analyze their impurities. Titanium oxide produced by the liquid phase method contains zirconium, niobium, and other impurities derived from the ilmenite ore. In contrast, the gas phase method involves purifying titanium tetrachloride and removing the impurities, resulting in titanium oxide that contains almost no impurities.

While titanium oxide produced by the gas-phase method has the advantage of being able to produce uniform particle sizes, it is difficult to form secondary aggregates, which is thought to increase the apparent specific surface area and therefore the viscosity of the mixed solution during the reaction process. In contrast, titanium oxide (a) produced by the liquid-phase method is thought to form loose secondary aggregates during the calcination process, which have less cohesive force relative to the specific surface area (BET value) resulting from the primary particles, making it possible to suppress the viscosity of the mixed solution. For these reasons, titanium oxide (a) produced by the liquid-phase method is preferred because it can further improve the productivity of the visible-light-responsive photocatalyst (D) and the abrasion resistance, flex resistance, flexibility, durability, and chemical resistance of the glove, and it is preferable that it substantially contain at least one metal element selected from the group consisting of zirconium and niobium.

In the present invention, the raw ore for titanium oxide may be ilmenite ore, or titanium slag obtained by metallurgically treating ilmenite ore to increase the titanium purity may be used.
The zirconium content ratio (Zr/Ti ratio) relative to 100% titanium in the titanium oxide (a) is preferably 0.03 or more, more preferably 0.04 or more, and even more preferably 0.05 or more, and is preferably 0.8 or less, more preferably 0.5 or less, and even more preferably 0.3 or less. Any combination of these upper and lower limits may be used. The zirconium content ratio (Zr/Ti ratio) relative to 100% titanium in the titanium oxide (a) is preferably 0.03 to 0.8, more preferably 0.04 to 0.5, and even more preferably 0.05 to 0.3. The niobium content ratio (Nb/Ti ratio) relative to 100% titanium in the titanium oxide composition is preferably 0.05 or more, more preferably 0.08 or more, and even more preferably 0.1 or more, and is preferably 0.8 or less, more preferably 0.5 or less, and even more preferably 0.3 or less. Any combination of these upper and lower limits may be used. The content ratio of niobium to titanium (Nb/Ti ratio) in the titanium oxide composition is preferably 0.05 to 0.8, more preferably 0.08 to 0.5, and even more preferably 0.10 to 0.3. A titanium oxide composition within the above range has high dispersibility in a solvent, and the mixed liquid is easy to handle even when the titanium oxide concentration is increased.

The titanium oxide (a) substantially containing a metal element (zirconium and/or niobium) means that the content ratio of the metal element in the titanium oxide is 0.02 or more relative to 100% of titanium. The titanium oxide substantially containing a metal element (zirconium and/or niobium) is a titanium oxide composition substantially containing a metal element (zirconium and/or niobium).
The titanium oxide of the present invention, which substantially contains a metal element (zirconium and/or niobium), has a low cohesive force relative to the specific surface area (BET value) resulting from the primary particles, and is therefore capable of suppressing the viscosity of the mixed liquid, which is presumably responsible for improving the concentration of titanium oxide.

The BET specific surface area of the titanium oxide (a) is preferably in the range of 1 to 200 m ² /g, more preferably 3 to 100 m ² /g, more preferably 4 to 70 m ² /g, and even more preferably 4 to 50 m 2 /g, from the viewpoint of obtaining even better antiviral properties, visible light responsiveness, and weather resistance, and is preferably in the range of 6 to 20 m ² /g from the viewpoint of further increasing the productivity of the visible light responsive photocatalyst ( ^D ). The method for measuring the BET specific surface area of the rutile-type titanium oxide (a1) will be described in the Examples below.

The primary particle diameter of the titanium oxide (a) is preferably in the range of 0.01 to 0.5 μm, more preferably 0.06 to 0.35 μm, in order to obtain even better antiviral properties, visible light responsiveness, and weather resistance. The primary particle diameter of the titanium oxide (a) is measured using a transmission electron microscope (TEM) to directly measure the size of primary particles from electron micrographs. Specifically, the minor axis diameter and major axis diameter of each titanium oxide primary particle are measured, and the average is taken as the particle diameter of the primary particle. Next, the volume (weight) of each of 100 or more titanium oxide particles is calculated by approximating it to the cube of the calculated particle diameter, and the volume-average particle diameter is taken as the average primary particle diameter.

Furthermore, as the visible light responsive photocatalyst, it is preferable to use titanium oxide (a) supported with a metal compound, as this further improves photocatalytic activity in the visible light range and makes it easier to exhibit appropriate activity capable of decomposing dirt components under practical indoor lighting.

Examples of the metal compound that can be used include copper compounds, iron compounds, tungsten compounds, and zinc compounds. Among these, copper compounds are preferred, and divalent copper compounds are more preferred, as they provide even more excellent antibacterial and antiviral properties. Known methods can be used to support the metal compound on the titanium oxide (a).

Next, we will explain the most preferred method of supporting a divalent copper compound on titanium oxide (a).

An example of a method for supporting a divalent copper compound on the titanium oxide (a) is a method including a mixing step (i) of titanium oxide (a) containing rutile-type titanium oxide (a1), a divalent copper compound raw material (b), water (c), and an alkaline substance (d).

The concentration of the titanium oxide (a) in the mixing step (i) is preferably in the range of 3 to 40% by mass. In the present invention, when titanium oxide (a) produced by a liquid phase method is used, the mixing step can be carried out with ease of handling even if the concentration of titanium oxide (a) is increased. Specifically, the mixing step can be carried out satisfactorily even when the concentration of titanium oxide (a) is in the range of more than 25% by mass but not more than 40% by mass.

The divalent copper compound raw material (b) can be, for example, an inorganic divalent copper compound, an organic divalent copper compound, or the like.

Examples of the divalent copper inorganic compound that can be used include inorganic acid salts of divalent copper such as copper sulfate, copper nitrate, copper iodate, copper perchlorate, copper oxalate, copper tetraborate, ammonium copper sulfate, copper amidosulfate, ammonium copper chloride, copper pyrophosphate, and copper carbonate; divalent copper halides such as copper chloride, copper fluoride, and copper bromide; copper oxide, copper sulfide, azurite, malachite, and copper azide. These compounds may be used alone or in combination of two or more.

Examples of the divalent copper organic compounds include copper formate, copper acetate, copper propionate, copper butyrate, copper valerate, copper caproate, copper enanthate, copper caprylate, copper pelargonate, copper caprate, copper myristic acid, copper palmitate, copper margarate, copper stearate, copper oleate, copper lactate, copper malate, copper citrate, copper benzoate, copper phthalate, copper isophthalate, copper terephthalate, copper salicylate, copper mellitic acid, copper oxalate, copper malonate, copper succinate, copper glutarate, copper adipate, copper fumarate, and glycol. Examples of compounds that can be used include copper nitrate, copper glycerate, copper gluconate, copper tartrate, copper acetylacetonate, copper ethylacetoacetate, copper isovalerate, copper β-resorcylate, copper diacetoacetate, copper formylsuccinate, copper salicylamine, copper bis(2-ethylhexanoate), copper sebacate, copper naphthenate, copper oxine, copper acetylacetonate, copper ethylacetoacetate, copper trifluoromethanesulfonate, copper phthalocyanine, copper ethoxide, copper isopropoxide, copper methoxide, and copper dimethyldithiocarbamate. These compounds may be used alone or in combination of two or more.

As the divalent copper compound raw material (b), among those mentioned above, it is preferable to use one represented by the following general formula (1):
_CuX2 (1)
(In formula (1), X represents a halogen atom, CH ₃ COO, NO ₃ , or (SO ₄ ) _1/2 .)

In formula (1), X is more preferably a halogen atom, and even more preferably a chlorine atom.

The amount of the divalent copper compound raw material (b) used in the mixing step (i) is preferably in the range of 0.01 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, and even more preferably 0.3 to 10 parts by mass, per 100 parts by mass of the titanium oxide (a).

The water (c) is the solvent used in the mixing step (i). Water alone is preferred, but other solvents may be included as needed. Examples of other solvents that can be used include alcohol solvents such as methanol, ethanol, 1-propanol, 2-propanol, and 1-butanol; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone; dimethylformamide, tetrahydrofuran, and the like. These solvents may be used alone or in combination of two or more.

Examples of the alkaline substance (d) that can be used include sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide, tetrabutylammonium hydroxide, triethylamine, trimethylamine, ammonia, and basic surfactants, with sodium hydroxide being preferred.

The alkaline substance (d) is preferably added as a solution, as this makes it easier to control the reaction. The concentration of the alkaline solution added is preferably in the range of 0.1 to 5 mol/L, more preferably in the range of 0.3 to 4 mol/L, and even more preferably in the range of 0.5 to 3 mol/L.

The mixing step (i) simply involves mixing the titanium oxide (a), divalent copper compound raw material (b), water (c), and alkaline substance (d). For example, one method involves first mixing titanium oxide (a) with water (c) and stirring as necessary, then adding divalent copper compound raw material (b) and stirring, and then adding alkaline substance (d) and stirring. This mixing step (i) results in the divalent copper compound derived from the divalent copper compound raw material (b) being supported on the titanium oxide (a).

The total stirring time in the mixing step (i) is, for example, 5 to 120 minutes, and preferably 10 to 60 minutes. The temperature during the mixing step (i) is, for example, in the range of room temperature to 70°C.

In order to ensure good support of the divalent copper compound on the titanium oxide (a), the titanium oxide (a), the divalent copper compound raw material (b), and water (c) are mixed and stirred, and then the alkaline substance (d) is mixed and stirred. The pH of the resulting mixture is preferably in the range of 8 to 11, and more preferably in the range of 9.0 to 10.5.

After the mixing step (i) is completed, the mixed liquid can be separated as a solid content. Examples of methods for this separation include filtration, sedimentation, centrifugation, and evaporation/drying, with filtration being preferred. The separated solid content may then be washed with water, crushed, classified, etc., as necessary.

After obtaining the solid content, it is preferable to heat-treat the solid content, as this allows the divalent copper compound derived from the divalent copper compound raw material (b) supported on the titanium oxide (a) to be more firmly bonded. The heat treatment temperature is preferably in the range of 150 to 600°C, more preferably in the range of 250 to 450°C. The heat treatment time is preferably 1 to 10 hours, more preferably 2 to 5 hours.

The above method produces a titanium oxide composition containing titanium oxide in which a divalent copper compound is supported on titanium oxide (a). From the perspective of photocatalytic activity, including antiviral activity, the amount of divalent copper compound supported on the titanium oxide (a) is preferably in the range of 0.01 to 20 parts by mass per 100 parts by mass of titanium oxide (a). The amount of divalent copper compound supported can be adjusted by the amount of divalent copper compound raw material (b) used in the mixing step (i).

The content of the visible light responsive photocatalyst (D) is preferably in the range of 0.5 to 70 parts by mass, more preferably 2 to 50 parts by mass, per 100 parts by mass of the solid content of the composite resin (ABC) in order to improve antiviral properties and weather resistance, and even more preferably 2 to 30 parts by mass in order to achieve better appearance (initial gloss).

The resin composition of the present invention contains the composite resin (ABC) and the visible light responsive photocatalyst (D) as essential components, but may also contain other additives as needed.

Examples of the other additives that can be used include curing agents (E), aqueous media, thermosetting resins, inorganic particles, curing catalysts, inorganic pigments, organic pigments, extender pigments, waxes, surfactants, stabilizers, flow adjusters, dyes, leveling agents, rheology control agents, ultraviolet absorbers, and antioxidants. These additives may be used alone or in combination of two or more.

Examples of the aqueous medium include water, water-miscible organic solvents, and mixtures thereof. Examples of water-miscible organic solvents include alcohols such as methanol, ethanol, n- and isopropanol; ketones such as acetone and methyl ethyl ketone; polyalkylene glycols such as ethylene glycol, diethylene glycol, and propylene glycol; alkyl ethers of polyalkylene glycols; and lactams such as N-methyl-2-pyrrolidone. In the present invention, water alone may be used, or a mixture of water and a water-miscible organic solvent may be used, or a water-miscible organic solvent alone may be used. From the standpoints of safety and environmental impact, water alone or a mixture of water and a water-miscible organic solvent is preferred, with water alone being particularly preferred.

The resin composition of the present invention preferably has a non-volatile content of 20 to 70% by mass, more preferably 30 to 60% by mass, from the viewpoints of suppressing a sudden increase in viscosity during production and improving the productivity, ease of application, and drying properties of the resin composition.

Examples of the thermosetting resin include vinyl resins, polyester resins, polyurethane resins, epoxy resins, epoxy ester resins, acrylic resins, phenolic resins, petroleum resins, ketone resins, silicone resins, and modified resins of these.

Examples of the inorganic particles include clay minerals, metals, metal oxides, and glass. Examples of the metals include gold, silver, copper, platinum, titanium, zinc, nickel, aluminum, iron, silicon, germanium, antimony, and oxides of these metals.

Specific examples of the curing agent (E) include compounds having silanol groups and/or hydrolyzable silyl groups, polyepoxy compounds, polyoxazoline compounds, polycarbodiimide compounds, polyisocyanate compounds, etc. In particular, when using a composite resin having carboxyl groups or carboxylate groups, it is preferable to use a combination of compounds having epoxy groups and silanol groups and/or hydrolyzable silyl groups, polyepoxy compounds, polyoxazoline compounds, and polycarbodiimide compounds.

Examples of compounds containing silanol groups and/or hydrolyzable silyl groups include the same silane compounds exemplified as those usable in producing the composite resin, as well as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and hydrolysis condensates thereof.

Examples of the polyepoxy compounds include polyglycidyl ethers having a structure derived from aliphatic or alicyclic polyols such as ethylene glycol, hexanediol, neopentyl glycol, trimethylolpropane, pentaerythritol, sorbitol, and hydrogenated bisphenol A; polyglycidyl ethers of aromatic diols such as bisphenol A, bisphenol S, and bisphenol F; polyglycidyl ethers of polyether polyols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol; polyglycidyl ethers of tris(2-hydroxyethyl)isocyanurate; polyglycidyl esters of aliphatic or aromatic polycarboxylic acids such as adipic acid, butanetetracarboxylic acid, phthalic acid, and terephthalic acid; bisepoxides of hydrocarbon dienes such as cyclooctadiene and vinylcyclohexene; and alicyclic polyepoxy compounds such as bis(3,4-epoxycyclohexylmethyl)adipate and 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate.

Examples of the polyoxazoline compound that can be used include 2,2'-p-phenylene-bis(1,3-oxazoline), 2,2'-tetramethylene-bis(1,3-oxazoline), 2,2'-octamethylene-bis(2-oxazoline), 2-isopropenyl-1,3-oxazoline, and polymers thereof.

Examples of the polyisocyanate compound that can be used include aromatic diisocyanates such as tolylene diisocyanate and diphenylmethane-4,4'-diisocyanate; aralkyl diisocyanates such as meta-xylylene diisocyanate and α,α,α',α'-tetramethyl-meta-xylylene diisocyanate; hexamethylene diisocyanate, lysine diisocyanate, 1,3-bisisocyanatomethylcyclohexane, 2-methyl-1,3-diisocyanatocyclohexane, 2-methyl-1,5-diisocyanatocyclohexane, and isophorone diisocyanate.

Furthermore, the polyisocyanate compound may also be any of various prepolymers having an isocyanate group, prepolymers having an isocyanurate ring, polyisocyanates having a biuret structure, and vinyl monomers having an isocyanate group.

The isocyanate groups of the polyisocyanate compound used as a curing agent may be blocked with a conventional blocking agent such as methanol, if necessary.

The curing agent (E) is preferably used in an amount of 0.1 to 50 parts by mass, more preferably 0.5 to 30 parts by mass, and particularly preferably 1 to 20 parts by mass, based on 100 parts by mass of the solid content of the composite resin (ABC).

Furthermore, when the composite resin (ABC) has carboxyl groups as hydrophilic groups, the curing agent (E) preferably has an equivalent of 0.2 to 5.0 reactive functional groups, such as epoxy groups, cyclocarbonate groups, hydroxyl groups, oxazoline groups, carbodiimide groups, and hydrazino groups, per equivalent of carboxyl groups in the composite resin (A), more preferably in the range of 0.5 to 3.0 equivalents, and particularly preferably in the range of 0.7 to 2.0 equivalents.

Examples of the curing catalyst that can be used include lithium hydroxide, sodium hydroxide, potassium hydroxide, sodium methylate, tetraisopropyl titanate, tetra-n-butyl titanate, tin octoate, lead octoate, cobalt octoate, zinc octoate, calcium octoate, zinc naphthenate, cobalt naphthenate, di-n-butyltin diacetate, di-n-butyltin dioctoate, di-n-butyltin dilaurate, di-n-butyltin maleate, p-toluenesulfonic acid, trichloroacetic acid, phosphoric acid, monoalkyl phosphate, dialkyl phosphate, monoalkyl phosphite, and dialkyl phosphite.

The aqueous resin composition of the present invention can be used in a variety of applications, such as coating agents and adhesives, and is particularly suitable for use as a coating agent.

Examples of substrates onto which the coating agent can be applied to form a coating film include inorganic substrates, plastic substrates, metal substrates, cloth, paper, and wood substrates.

Examples of inorganic substrates include those primarily composed of inorganic materials, such as cement-based substrates, silicate-based substrates such as calcium silicate, gypsum-based substrates, and ceramic-based substrates. For example, on-site construction (wet) substrates include exposed concrete, cement mortar, gypsum plaster, dolomite plaster, and plaster, while on-site production (dry) substrates include lightweight aerated concrete (ALC), asbestos cement, glass fiber-reinforced calcium silicate, gypsum board, fired clay such as tiles, and glass.

Examples of the plastic substrate include substrates made of polyolefins such as polyethylene, polypropylene, and ethylene-propylene copolymers; substrates made of polyesters such as polyethylene isophthalate, polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; substrates made of polyamides such as nylon 1, nylon 11, nylon 6, nylon 66, and nylon MX-D; substrates made of styrene polymers such as polystyrene, styrene-butadiene block copolymers, styrene-acrylonitrile copolymers, and styrene-butadiene-acrylonitrile copolymers (ABS resins); substrates made of acrylic polymers such as polymethyl methacrylate and methyl methacrylate-ethyl acrylate copolymers; and substrates made of polycarbonate. The plastic substrates may have a single layer or a laminate structure of two or more layers. Furthermore, these plastic substrates may be unstretched, uniaxially stretched, or biaxially stretched.

The plastic substrate may also contain additives such as antistatic agents, antifogging agents, antiblocking agents, antioxidants, light stabilizers, crystal nucleating agents, and lubricants, as needed, provided that the effects of the present invention are not impaired.

The plastic substrate may be subjected to various surface treatments to further improve adhesion to the coating agent of the present invention. Examples of such surface treatments include corona discharge treatment, plasma treatment, flame plasma treatment, electron beam irradiation treatment, and ultraviolet irradiation treatment. One or a combination of two or more of these treatments may also be used.

The shape of the substrate is not particularly limited and may be, for example, a sheet, plate, sphere, film, large structure, complex shaped assembly, or molded object.

The surface of the substrate may be previously coated with a primer paint or the like, and even if the coated area has deteriorated, it is possible to apply the coating agent of the present invention.

The primer paint may be any of a variety of water-soluble paints, water-dispersible paints, organic solvent-based paints, organic solvent-dispersed paints, powder paints, etc. Specifically, various types of paints can be used, such as acrylic resin-based paints, polyester resin-based paints, alkyd resin-based paints, epoxy resin-based paints, fatty acid-modified epoxy resin-based paints, silicone resin-based paints, polyurethane resin-based paints, fluoroolefin-based paints, and amine-modified epoxy resin paints.

The primer paint may be a clear paint that does not contain pigment, an enamel-based paint that contains pigment, or a metallic paint that contains aluminum flakes, etc.

The coating agent of the present invention can be applied to the substrate by a variety of coating methods, including brush coating, roller coating, spray coating, dip coating, flow coater coating, roll coater coating, and electrodeposition coating.

After applying the coating agent of the present invention to the surface of the substrate using the above coating method, leaving it at room temperature for approximately 1 to 10 days or heating it at a temperature range of 40 to 250°C for approximately 10 seconds to 2 hours will result in a coated object with a coating film that has excellent durability, crack resistance, weather resistance, and contamination resistance.

Articles bearing coating films formed using the coating agent of the present invention by the above-described method include, for example, the housings of home appliances such as televisions, refrigerators, washing machines, and air conditioners; the housings of electronic devices such as personal computers, smartphones, mobile phones, digital cameras, and game consoles; the housings of office equipment such as printers and facsimiles; and various plastic components such as various parts used in the interior materials of various vehicles such as automobiles and train cars. Other examples include interior and exterior building materials such as exterior walls, roofs, membrane structures, glass, and decorative panels; civil engineering materials such as soundproof walls and drainage ditches; and metal components such as zinc-plated steel sheets, aluminum-zinc alloy steel sheets, and other plated steel sheets, aluminum sheets, aluminum alloy sheets, electromagnetic steel sheets, copper sheets, and stainless steel sheets used in home appliances, industrial machinery, and automobile parts. Furthermore, since the coating agent of the present invention can form coating films with excellent substrate conformality, various functional films constituting polarizing plates for liquid crystal displays are also suitable.

Next, the present invention will be explained in detail using examples and comparative examples.

(Synthesis Example 1: Production of methyltrimethoxysilane condensate (c-1))
A reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, a condenser, and a nitrogen gas inlet was charged with 1,421 parts by mass of methyltrimethoxysilane (hereinafter abbreviated as "MTMS"), and the temperature was raised to 60° C. Next, a mixture of 0.17 parts by mass of isopropyl acid phosphate ("A-3" manufactured by Sakai Chemical Industry Co., Ltd., hereinafter abbreviated as "catalyst (1)") and 207 parts by mass of deionized water was added dropwise to the reaction vessel over 5 minutes, and the mixture was stirred at a temperature of 80° C. for 4 hours to carry out a hydrolysis condensation reaction.

The condensate obtained by the above hydrolysis and condensation reaction was distilled under reduced pressure of 300 to 10 mmHg (meaning that the pressure was reduced from 300 mmHg when methanol distillation began to drop, and was reduced to 10 mmHg at the end; the same applies below) at a temperature of 40 to 60°C to remove the methanol and water produced during the reaction, yielding 1,000 parts by mass of a liquid (70% by mass of active ingredient) containing MTMS condensate (c-1) having a number average molecular weight of 1,000.

The active ingredient is calculated by dividing the theoretical yield (parts by mass) when all methoxy groups of silane monomers such as MTMS undergo a condensation reaction by the actual yield (parts by mass) after the condensation reaction (theoretical yield (parts by mass) when all methoxy groups of silane monomers undergo a condensation reaction / actual yield (parts by mass) after the condensation reaction).

(Synthesis Example 2: Production of Composite Resin (ABC-1) Composition)
A reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, a condenser, and a nitrogen gas inlet was charged with 50 parts by mass of propylene glycol monopropyl ether (hereinafter abbreviated as "PnP"), 80 parts by mass of isopropyl alcohol (hereinafter abbreviated as "IPA"), 26 parts by mass of phenyltrimethoxysilane (hereinafter abbreviated as "PTMS"), and 15 parts by mass of dimethyldimethoxysilane (hereinafter abbreviated as "DMDMS"), and the temperature was raised to 80°C.
Next, at the same temperature, a mixture containing 96 parts by mass of methyl methacrylate (hereinafter abbreviated as "MMA"), 99 parts by mass of cyclohexyl methacrylate (hereinafter abbreviated as "CHMA"), 96 parts by mass of butyl acrylate (hereinafter abbreviated as "BA"), 13 parts by mass of acrylic acid (hereinafter abbreviated as "AA"), 16 parts by mass of 3-methacryloxypropyltrimethoxysilane (hereinafter abbreviated as "MPTS"), 16 parts by mass of IPA, and 16 parts by mass of tert-butylperoxy-2-ethylhexanoate (hereinafter abbreviated as "TBPEH") was added dropwise to the reaction vessel over 4 hours, and the mixture was further reacted at the same temperature for 2 hours to obtain an organic solvent solution of an acrylic polymer (a'-1) having a number average molecular weight of 19,000 and having carboxyl groups and hydrolyzable groups.
Next, a mixture of 0.4 parts by mass of catalyst (1) and 11 parts by mass of deionized water was added dropwise over 5 minutes, and the mixture was stirred at the same temperature for a further 10 hours to cause a hydrolysis condensation reaction, thereby obtaining a composite resin (A'B-1) consisting of a polymer segment having both a carboxyl group and a hydrolyzable group bonded to a silicon atom, and a polysiloxane segment derived from PTMS and DMDMS.
Next, 14 parts by mass of triethylamine (hereinafter abbreviated as "TEA") was added to neutralize the carboxyl groups in the composite resin (A'B-1) to form composite resin (AB-1), and then 81 parts by mass of a methyltrimethoxysilane condensate (c-1) was added, followed by 550 parts by mass of deionized water to produce composite resin (ABC-1) in which the composite resin (AB-1) and the polysiloxane segment (C-1) derived from the methyltrimethoxysilane condensate (c-1) were bonded by hydrolysis condensation, and the composite resin (ABC-1) was dispersed in an aqueous medium to obtain an aqueous dispersion of composite resin (ABC-1).
Next, the obtained aqueous dispersion was distilled for 2 hours under conditions of a reduced pressure of 300 to 10 mmHg and a temperature of 40 to 60°C to remove IPA, the produced methanol, and water, thereby obtaining 1,000 parts by mass of a composite resin (ABC-1) composition having a non-volatile content of 40.0%.

(Synthesis Example 3: Production of composite resin (ABC-2) composition)
Into a reaction vessel similar to that of Synthesis Example 1, 23.3 parts by mass of PTMS, 28 parts by mass of DMDMS, and 348.8 parts by mass of n-butyl acetate were charged as an initial solvent, and the mixture was heated to 95 ° C. while stirring under aeration of nitrogen gas. Next, as monomers, 125.2 parts by mass of MMA, 74.4 parts by mass of n-butyl methacrylate (hereinafter abbreviated as "BMA"), 91.6 parts by mass of BA, 4 parts by mass of methacrylic acid (hereinafter abbreviated as "MAA"), 12 parts by mass of MPTS, 92.8 parts by mass of 2-hydroxyethyl methacrylate (hereinafter abbreviated as "HEMA"), 40 parts by mass of n-butyl acetate, and 30 parts by mass of TBPEH were mixed, and the reaction vessel was maintained at 95 ° C. and added dropwise over 4 hours under aeration of nitrogen gas while stirring. After stirring for another 2 hours at the same temperature, a mixture of 0.064 parts by mass of catalyst (1) and 14.6 parts by mass of deionized water was added dropwise to the reaction vessel over 5 minutes, and the mixture was stirred at the same temperature for 4 hours to allow the hydrolysis and condensation reaction of PTMS, DMDMS, and MPTS to proceed, yielding 884 parts by mass of a polymer.
Next, 512.4 parts by mass of the obtained polymer and 100 parts by mass of methyltrimethoxysilane condensate (c-1) were charged and stirred for 5 minutes, after which 34.9 parts by mass of deionized water was added and stirred for 4 hours at 80 ° C. The resulting reaction product was distilled for 2 hours under reduced pressure of 1 to 30 kPa at 60 ° C. to remove the produced methanol and water, and then 40.5 parts by mass of propylene glycol monomethyl ether acetate (hereinafter abbreviated as "PGMAC") and 143.3 parts by mass of n-butyl acetate were added to obtain a composite resin (ABC-2) composition having a non-volatile content of 55.1% by mass.

Comparative Synthesis Example 1: Production of Polysiloxane-Free Acrylic Resin (R1) Composition
Into a reaction vessel similar to that of Synthesis Example 1, 284.1 parts by mass of diethylene glycol dimethyl ether was charged, stirring was started, and the temperature was raised to 135 ° C. To this, under a nitrogen stream, a mixture of 236.1 parts by mass of MMA, 101.2 parts by mass of BMA, 106.2 parts by mass of HEMA, and 4 parts by mass of TBPEH was continuously added dropwise over 1.5 hours. After stirring at the same temperature for 2 hours, the mixture was cooled to 80 ° C., 16 parts by mass of dimethylethanolamine was added, and then 588.3 parts by mass of ion-exchanged water was added, and the mixture was dispersed in water to obtain a polysiloxane-free acrylic resin water (R1) composition having a non-volatile content of 45.5% by mass.

Comparative Synthesis Example 2: Production of Polysiloxane-Free Acrylic Resin (R2) Composition
A reaction vessel similar to that used in Synthesis Example 1 was charged with 519 parts by mass of butyl acetate and stirred, and the temperature was raised to 130°C. Under a nitrogen stream, 336.4 parts by mass of MMA, a mixture of 130 parts by mass of BMA, 145.6 parts by mass of HEMA, and 15 parts by mass of MAA, and 12 parts by mass of TBPEH were continuously added dropwise over 4 hours. The mixture was stirred at the same temperature for 4 hours, yielding a polysiloxane-free acrylic resin (R2) composition with a nonvolatile content of 55% by mass.

(Synthesis Example 4)
(1) Titanium oxide a) Crystalline rutile titanium oxide b) Manufacturing method: Liquid phase method (sulfuric acid method)
c) Physical properties: BET specific surface area: 9.0 m ² /g
- Rutile rate: 95.4%
・Primary particle size: 0.18μm
・Zr/Ti ratio: 0.05
・Nb/Ti ratio: 0.17

(2) Manufacturing process a) Mixing process (reaction process)
600 parts by mass of the titanium oxide, 8 parts by mass of copper(II) chloride dihydrate, and 900 parts by mass of water were mixed in a stainless steel container. The mixture was then stirred with a stirrer ("Robomix" manufactured by Tokushu Kika Kogyo Co., Ltd.), and a 1 mol/L aqueous solution of sodium hydroxide was added dropwise until the pH of the mixture reached 10.
b) Dehydration step: The mixture was filtered under reduced pressure using qualitative filter paper (5C) to separate the solid matter from the mixture, and then washed with ion-exchanged water. The washed solid matter was then dried at 120°C for 12 hours to remove moisture. After drying, the mixture was milled ("Miller" manufactured by Iwatani Sangyo Co., Ltd.) to obtain a powdery titanium oxide composition.
c) Heat Treatment Step Heat treatment was carried out at 450°C for 3 hours in the presence of oxygen using a precision incubator (DH650 manufactured by Yamato Scientific Co., Ltd.), to obtain a titanium oxide composition containing titanium oxide carrying a divalent copper compound.
The amount of the divalent copper compound carried on the titanium oxide supporting the divalent copper compound was 0.5% by mass relative to the titanium oxide.

(Example 1: Preparation of resin composition (1))
A pigment dispersion was obtained by adding 100 parts by mass of the composite resin (ABC-1) composition obtained in Synthesis Example 2, 3.1 parts by mass of the titanium oxide composition obtained in Synthesis Example 4, 27.4 parts by mass of a titanium oxide pigment ("Ti-Pure R-706" manufactured by Chemours), and 19.9 parts by mass of ion-exchanged water, and kneading them for 30 minutes with a sand mill ("Sand Grinder" manufactured by Imex Co., Ltd.). A mixture of 4.6 parts by mass of "KBM-403" manufactured by Shin-Etsu Chemical Co., Ltd. and 1.2 parts by mass of "KBM-402" manufactured by the same company as a curing agent was added to the obtained pigment dispersion, and the mixture was stirred for 5 minutes with a disper ("Homodisper" manufactured by Primix Corporation) to obtain resin composition (1).

(Example 2: Preparation of resin composition (2))
Resin composition (2) was obtained in the same manner as in Example 1, except that the amount of titanium oxide composition used was changed from 3.1 parts by mass to 7.6 parts by mass, and the amount of titanium oxide pigment used was changed from 27.4 parts by mass to 22.9 parts by mass.

(Example 3: Preparation of resin composition (3))
A pigment dispersion was obtained by adding 100 parts by mass of the composite resin (ABC-2) composition obtained in Synthesis Example 3, 4.6 parts by mass of the titanium oxide composition obtained in Synthesis Example 4, 41.3 parts by mass of a titanium oxide pigment ("Ti-Pure R-706" manufactured by Chemours), and 10 parts by mass of butyl acetate, and kneading the mixture for 30 minutes using a sand mill ("Sand Grinder" manufactured by Imex Co., Ltd.). 18.6 parts by mass of "DN-980" manufactured by DIC Corporation was added to the obtained pigment dispersion as a curing agent, and the mixture was stirred for 5 minutes using a disper ("Homodisper" manufactured by Primix Corporation), to obtain resin composition (3).

(Example 4: Preparation of resin composition (4))
Resin composition (4) was obtained in the same manner as in Example 3, except that the amount of titanium oxide composition used was changed from 4.6 parts by mass to 11.5 parts by mass, and the amount of titanium oxide pigment used was changed from 41.3 parts by mass to 34.4 parts by mass.

(Example 5: Preparation of resin composition (5))
Resin composition (5) was obtained in the same manner as in Example 1, except that the amount of titanium oxide composition used was changed from 3.1 parts by mass to 1.5 parts by mass, and the amount of titanium oxide pigment used was changed from 27.4 parts by mass to 29 parts by mass.

(Example 6: Preparation of resin composition (6))
Resin composition (6) was obtained in the same manner as in Example 3, except that the amount of titanium oxide composition used was changed from 4.6 parts by mass to 2.3 parts by mass, and the amount of titanium oxide pigment used was changed from 41.3 parts by mass to 43.6 parts by mass.

(Example 7: Preparation of resin composition (7))
Resin composition (7) was obtained in the same manner as in Example 1, except that the amount of titanium oxide composition used was changed from 3.1 parts by mass to 30.5 parts by mass and no titanium oxide pigment was used.

(Example 8: Preparation of resin composition (8))
Resin composition (8) was obtained in the same manner as in Example 3, except that the amount of titanium oxide composition used was changed from 4.6 parts by mass to 45.9 parts by mass and no titanium oxide pigment was used.

(Comparative Example 1: Preparation of Resin Composition (R1))
A pigment dispersion was obtained by adding 100 parts by mass of the polysiloxane-free acrylic resin (R1) composition obtained in Comparative Synthesis Example 1, 4.4 parts by mass of the titanium oxide composition obtained in Synthesis Example 4, 39.2 parts by mass of a titanium oxide pigment ("Ti-Pure R-706" manufactured by Chemours), and 19.9 parts by mass of ion-exchanged water, and kneading the mixture for 30 minutes using a sand mill ("Sand Grinder" manufactured by Imex Co., Ltd.). To the resulting pigment dispersion, a mixture containing 25 parts by mass of "DNW-5500" manufactured by DIC Corporation as a curing agent was added, and the mixture was stirred for 5 minutes using a disper ("Homodisper" manufactured by Primix Corporation), to obtain resin composition (R1).

(Comparative Example 2: Preparation of Resin Composition (R2))
Resin composition (R2) was obtained in the same manner as in Comparative Example 1, except that the amount of titanium oxide composition used was changed from 4.4 parts by mass to 8.8 parts by mass, and the amount of titanium oxide pigment used was changed from 39.2 parts by mass to 34.8 parts by mass.

(Comparative Example 3: Preparation of Resin Composition (R3))
A pigment dispersion was obtained by adding 100 parts by mass of the polysiloxane-free acrylic resin (R2) composition obtained in Comparative Synthesis Example 2, 5 parts by mass of the titanium oxide composition obtained in Synthesis Example 4, 45.3 parts by mass of a titanium oxide pigment ("Ti-Pure R-706" manufactured by Chemours), and 10 parts by mass of butyl acetate, and kneading the mixture for 30 minutes using a sand mill ("Sand Grinder" manufactured by Imex Co., Ltd.). To the resulting pigment dispersion, a mixture containing 26.6 parts by mass of "DN-980" manufactured by DIC Corporation as a curing agent was added, and the mixture was stirred for 5 minutes using a disper ("Homodisper" manufactured by Primix Corporation), to obtain resin composition (R3).

(Comparative Example 4: Preparation of Resin Composition (R4))
A resin composition (R4) was obtained in the same manner as in Comparative Example 3, except that the amount of titanium oxide composition used was changed from 5 parts by mass to 10 parts by mass, and the amount of titanium oxide pigment used was changed from 45.3 parts by mass to 40.3 parts by mass.

(Comparative Example 5: Preparation of Resin Composition (R5))
A pigment dispersion was obtained by adding 100 parts by mass of the composite resin (ABC-1) composition obtained in Synthesis Example 2, 45.9 parts by mass of a titanium oxide pigment ("Ti-Pure R-706" manufactured by Chemours), and 10 parts by mass of butyl acetate, and kneading the mixture for 30 minutes using a sand mill ("Sand Grinder" manufactured by Imex Co., Ltd.). 18.5 parts by mass of "DN-980" manufactured by DIC Corporation was added to the obtained pigment dispersion as a curing agent, and the mixture was stirred for 5 minutes using a disper ("Homodisper" manufactured by Primix Corporation), to obtain resin composition (R5).

(Comparative Example 6: Preparation of Resin Composition (R6))
A pigment dispersion was obtained by adding 100 parts by mass of the polysiloxane-free acrylic resin (R2) composition obtained in Comparative Synthesis Example 2, 50.3 parts by mass of a titanium oxide pigment ("Ti-Pure R-706" manufactured by Chemours), and 10 parts by mass of butyl acetate, and kneading the mixture for 30 minutes using a sand mill ("Sand Grinder" manufactured by Imex Co., Ltd.). To the resulting pigment dispersion, a mixture containing 26.6 parts by mass of "DN-980" manufactured by DIC Corporation as a curing agent was added, and the mixture was stirred for 5 minutes using a disper ("Homodisper" manufactured by Primix Corporation), to obtain resin composition (R6).

[Method for preparing cured coating film for evaluation]
The resin compositions obtained in the Examples and Comparative Examples were spray-coated onto a chromate-treated aluminum plate manufactured by Engineering Test Service Co., Ltd. so that the film thickness after drying would be 15 μm, and the coating was dried in an environment of 23° C. for one week to obtain a cured coating film for evaluation.

[Evaluation of antiviral activity]
The obtained cured coating film for evaluation was subjected to an anti-phage virus test (see JIS R1756:2020).

1) The light irradiation conditions were white fluorescent light with ultraviolet rays cut off by an N113 filter, and the illuminance was set to 500 lux.
2) 100 μL of a Qβ phage solution with a known concentration was dropped onto a 5 cm×5 cm test plate obtained in the Examples and Comparative Examples, and then a 4 cm×4 cm adhesive film was placed over the plate to prepare a sample for evaluation.
3) The sample irradiated for 8 hours was collected in SCDLP solution, appropriately diluted, infected with Escherichia coli, spread on an agar medium, and evaluated by counting the number of colonies after incubation. The antiviral activity was evaluated based on the degree of inactivation of Qβ phage according to the following criteria.
Inactivation degree = log (N/N0)
N: infectious titer of sample after reaction, NO: infectious titer of inoculated phage.
Inactivation degree-1 indicates 90% inactivation, inactivation degree-2 indicates 99%, and inactivation degree-3 indicates 99.9% inactivation.
"◎": Inactivation degree is -3 or less "〇": Inactivation degree is greater than -3 and less than -2 "×": Inactivation degree is greater than -2

[Weather resistance evaluation]
The obtained cured coating film for evaluation was subjected to an accelerated weather resistance test for 500 hours under the conditions below using a Super Xenon Weather Meter Tester "SX2-75" manufactured by Suga Test Instruments Co., Ltd., and evaluated in terms of gloss retention.
Irradiance: 180 W/m ² (wavelength range: 300 to 700 nm)
Black panel temperature: 63°C
Irradiation and spraying method: 120 minute cycle (102 minutes of irradiation followed by 18 minutes of irradiation and spraying [gloss retention])
The 60-degree specular reflectance (%) of the cured coating film before and after the test was measured using a gloss meter (micro-TRI-gloss) manufactured by BYK Japan KK, and the 60-degree specular reflectance (%) of the cured coating film after the test was divided by the 60-degree specular reflectance (%) of the cured coating film before the test, and the result was multiplied by 100 to represent the gloss retention (%).
[Initial gloss]
The 60-degree specular reflectance (%) of the cured coating film before the test, measured as described above, was taken as the initial gloss.

As shown in Examples 1 to 8, the aqueous resin composition of the present invention was found to have excellent antiviral properties and weather resistance.

On the other hand, Comparative Examples 1 to 4, which used acrylic resins without a polysiloxane structure, exhibited poor weather resistance.

Comparative Example 5, which does not contain visible light-responsive photocatalyst (D), had poor antiviral properties.

Comparative Example 6 uses an acrylic resin that does not have a polysiloxane structure and does not contain visible light-responsive photocatalyst (D), but the weather resistance and antiviral properties were poor.

Claims (6)

A resin composition comprising: a composite resin (ABC) in which a polysiloxane segment (B) of the composite resin (AB) in which a polymer segment (A) and a polysiloxane segment (B) are chemically bonded to each other, and a polysiloxane segment (C) derived from a condensate (c) of an alkyltrialkoxysilane in which the alkyl group has 1 to 3 carbon atoms, is bonded via a silicon-oxygen bond; and a visible light responsive photocatalyst (D) , wherein the visible light responsive photocatalyst (D) is formed by supporting a metal compound on titanium oxide (a), and the content of the visible light responsive photocatalyst (D) is in the range of 0.5 to 30 parts by mass per 100 parts by mass of the solid content of the composite resin (ABC). 2. The resin composition according to claim 1, wherein the polysiloxane segment (B) has a structure represented by the following general formula (1) and/or (2):
(In general formulas (1) and (2), ^R1 is an organic group having 4 to 12 carbon atoms bonded to a silicon atom, and ^R2 and ^R3 are each independently a methyl group bonded to a silicon atom or an ethyl group bonded to a silicon atom.) 2. The resin composition according to claim 1 , wherein the titanium oxide (a) comprises rutile-type titanium oxide (a1). 4. The resin composition according to claim 1 , wherein the metal compound is a divalent copper compound. A coating agent comprising the resin composition according to any one of claims 1 to 4 . An article having a cured coating film of the coating agent according to claim 5 .