Patent Description:
Aquatic fouling organisms such as barnacles, tubeworms, common mussels, brown bryozoan, sea squirts, green laver, sea lettuce, and slimes adhere to ships (especially ship bottoms), fishing tools such as fishing nets and fishing net accessories, and structures submerged in seawater such as power plant aqueducts, leading to dysfunction, impaired appearance, and other problems of the ships and the like.

In order to prevent such problems, there has been a technique to apply an antifouling coating composition onto ships and the like to form an antifouling coating film. Controlled release of an antifouling agent from the antifouling coating film allows to exhibit antifouling property for a long period of time (Patent Literatures <NUM> to <NUM>).

However, the dissolution properties of the antifouling coating film comprising a polymer containing (meth)acrylic acid alkoxy carbonyl methyl ester group disclosed in Patent Literatures <NUM> to <NUM> were extremely low, and thus it was difficult to exhibit antifouling property for a long period of time.

To solve these problems, the technology to dissolve the coating film and exhibit antifouling property for a long period of time has been proposed (Patent Literature <NUM>).

Although the dissolution property and the like of the antifouling coating film comprising the antifouling coating composition disclosed in Patent Literature <NUM> has been improved, there is still room for improvement in terms of coating film properties such as cracking and peeling, and an antifouling coating composition capable of maintaining excellent coating film surface condition and antifouling performance for a long period of time has been desired.

The present invention has been made by taking the afore-mentioned problems into consideration. The present invention provides an antifouling coating composition capable of maintaining excellent coating film surface condition and antifouling performance for a long period of time.

According to the present invention, provided is an antifouling coating composition containing a copolymer A and an antifouling agent, wherein: the copolymer A is a copolymer of a monomer (a) and an ethylenically unsaturated monomer (b) other than the monomer (a); the monomer (a) is constituted of a monomer (a1) and a monomer (a2); the monomer (a1) is represented by general formula (<NUM>); the monomer (a2) is represented by general formula (<NUM>); and a content of the monomer (a1) in the monomer (a) is <NUM> to <NUM> mass%.

The inventors have conducted intensive studies to solve the above-mentioned problems and have found that the composition containing the copolymer A and the antifouling agent can solve the above-mentioned problems, thereby leading to completion of the present invention.

The antifouling coating composition of the present invention contains a copolymer A and an antifouling agent, and may contain a copolymer B and other additives.

The copolymer A is a copolymer of a monomer (a) and an ethylenically unsaturated monomer (b) other than the monomer (a), and contains a monomer unit derived from the monomer (a) and the monomer (b). The content of the monomer (a) to the total of the monomer (a) and the monomer (b) is preferably <NUM> to <NUM> mass%, and more preferably <NUM> to <NUM> mass%. The content is, specifically for example, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> mass%, and may be in the range between the two values exemplified herein. In this case, the dissolution property of the coating film is particularly excellent.

The monomer (a) is constituted of a monomer (a1) and a monomer (a2). The content of the monomer (a1) in the monomer (a) is <NUM> to <NUM> mass%, preferably <NUM> to <NUM> mass%, and more preferably <NUM> to <NUM> mass%. Compared to the monomer (a2), the monomer (a1) has the property to increase the coating film strength and decrease the dissolution property of the coating film. For this reason, if the content of the monomer (a1) is too small, the coating film strength may be too low, and the coating film surface condition may easily deteriorate after a long period of time. On the other hand, if the content of the monomer (a1) is too high, the dissolution property of the coating film may be too low, resulting in reduced antifouling performance. The content of the monomer (a1) is, for example, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> mass%, and may be in the range between the two values exemplified herein.

The monomer (a1) is represented by general formula (<NUM>).

In general formula (<NUM>), R<NUM> represents a hydrogen atom or a methyl group, R<NUM> represents a hydrogen atom, a methyl group, or a phenyl group, and R<NUM> represents an alkyl group which may be substituted with an alkoxy group having <NUM> to <NUM> carbon atoms or a phenyl group, or a phenyl group, the alkyl group having <NUM> to <NUM> carbon atoms.

Preferably, R<NUM> is a hydrogen atom or a methyl group. The number of carbon atoms of the alkoxy or alkyl group in R<NUM> is, for example, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, and may be in the range between the two values exemplified herein. R<NUM> is, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a t-butyl group, a <NUM>-ethylhexyl group, a cyclohexyl group, a benzyl group, a phenyl group, a <NUM>-methoxyethyl group, a <NUM>-methoxybutyl group, a vinyl group, or an allyl group, and preferably a methyl group, an ethyl group, an isopropyl group, or an n-butyl group.

Examples of the monomer (a1) include methoxycarbonylmethyl (meth)acrylate, ethoxycarbonylmethyl (meth)acrylate, isopropoxycarbonylmethyl (meth)acrylate, n-propoxycarbonylmethyl (meth)acrylate, n-butoxycarbonylmethyl (meth)acrylate, t-butoxycarbonylmethyl (meth)acrylate, <NUM>-ethylhexyloxycarbonylmethyl (meth)acrylate, cyclohexyloxycarbonylmethyl (meth)acrylate, benzyloxycarbonylmethyl (meth)acrylate, phenoxycarbonylmethyl (meth)acrylate, <NUM>-methoxyethoxycarbonylmethyl (meth)acrylate, <NUM>-methoxybutoxycarbonylmethyl (meth)acrylate, aryloxycarbonylmethyl (meth)acrylate, vinyloxycarbonylmethyl (meth)acrylate, <NUM>-(methoxycarbonyl)ethyl (meth)acrylate, <NUM>-(ethoxycarbonyl)ethyl (meth)acrylate, <NUM>-(n-propoxycarbonyl)ethyl (meth)acrylate, <NUM>-(isopropoxycarbonyl)ethyl (meth)acrylate, <NUM>-(n-butoxycarbonyl) ethyl (meth)acrylate, <NUM>-(t-butoxycarbonyl)ethyl (meth)acrylate, α-(methoxycarbonyl)benzyl (meth)acrylate and α-(ethoxycarbonyl)benzyl (meth)acrylate. Among them, methoxycarbonylmethyl (meth)acrylate, ethoxycarbonylmethyl (meth)acrylate, isopropoxycarbonylmethyl (meth)acrylate, n-propoxycarbonylmethyl (meth)acrylate, n-butoxycarbonylmethyl (meth)acrylate, <NUM>-(methoxycarbonyl)ethyl (meth)acrylate, and <NUM>-(ethoxycarbonyl)ethyl (meth)acrylate are preferred.

The monomer (a2) is represented by general formula (<NUM>). <CHM>
<CHM>.

In general formula (<NUM>), R<NUM> represents a hydrogen atom or a methyl group, R<NUM> represents a hydrogen atom, a methyl group, or a phenyl group, R<NUM> represents an alkyl group which may be substituted with an alkoxy group having <NUM> to <NUM> carbon atoms or a phenyl group, or a phenyl group, the alkyl group having <NUM> to <NUM> carbon atoms, and n represents an integer of <NUM> to <NUM>.

Descriptions of R<NUM> and R<NUM> are the same as those of R<NUM> and R<NUM>, respectively.

n represents an integer of <NUM> to <NUM>, and is preferably <NUM> to <NUM> in terms of long-term antifouling property. n is, for example, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, and may be in the range between the two values exemplified herein.

Preferably, the monomer (a2) contains both the compound where n is <NUM> and the compound where n is <NUM> or greater. In this case, a tendency for stable dissolution of the coating film to continue is observed.

Examples of the monomer (a2) include methyldi(oxycarbonylmethyl) (meth)acrylate, ethyldi(oxycarbonylmethyl) (meth)acrylate, isopropyldi(oxycarbonylmethyl) (meth)acrylate, n-propyldi(oxycarbonylmethyl) (meth)acrylate, n-butyldi(oxycarbonylmethyl) (meth)acrylate, t-butyldi(oxycarbonylmethyl) (meth)acrylate, <NUM>-ethylhexyldi(oxycarbonylmethyl) (meth)acrylate, cyclohexyldi(oxycarbonylmethyl) (meth)acrylate, benzyldi(oxycarbonylmethyl) (meth)acrylate, phenyldi(oxycarbonylmethyl) (meth)acrylate, <NUM>-methoxyethyldi(oxycarbonylmethyl) (meth)acrylate, <NUM>-methoxybutyldi(oxycarbonylmethyl) (meth)acrylate, allyldi(oxycarbonylmethyl) (meth)acrylate, vinyldi(oxycarbonylmethyl) (meth)acrylate, methyldi[<NUM>-(oxypolycarbonyl)ethyl] (meth)acrylate, ethyldi[<NUM>-(oxypolycarbonyl)ethyl] (meth)acrylate, n-propyldi[<NUM>-(oxypolycarbonyl)ethyl] (meth)acrylate, isopropyl di[<NUM>-(oxypolycarbonyl)ethyl] (meth)acrylate, n-butyldi[<NUM>-(oxypolycarbonyl)ethyl] (meth)acrylate, t-butyldi[<NUM>-(oxypolycarbonyl)ethyl] (meth)acrylate, methyldi[α-(oxycarbonyl)benzyl] (meth)acrylate, and ethyldi[α-(oxycarbonyl)benzyl] (meth)acrylate. Preferably, the examples include methyldi(oxycarbonylmethyl) (meth)acrylate, ethyldi(oxycarbonylmethyl) (meth)acrylate, isopropyldi(oxycarbonylmethyl) (meth)acrylate, n-propyl di(oxycarbonylmethyl) (meth)acrylate, n-butyldi(oxycarbonylmethyl) (meth)acrylate, methyldi[<NUM>-(oxypolycarbonylethyl)] (meth)acrylate, ethyldi[<NUM>-(oxypolycarbonylethyl)] (meth)acrylate, methylpoly(oxycarbonylmethyl) (meth)acrylate, ethylpoly(oxycarbonylmethyl) (meth)acrylate, isopropylpoly(oxycarbonylmethyl) (meth)acrylate, n-propylpoly(oxycarbonylmethyl) (meth)acrylate, n-butylpoly(oxycarbonylmethyl) (meth)acrylate, t-butylpoly(oxycarbonylmethyl) (meth)acrylate, <NUM>-ethylhexylpoly(oxycarbonylmethyl) (meth)acrylate, cyclohexylpoly(oxycarbonylmethyl) (meth)acrylate, benzylpoly(oxycarbonylmethyl) (meth)acrylate, phenylpoly(oxycarbonylmethyl) (meth)acrylate, <NUM>-methoxyethylpoly(oxycarbonylmethyl) (meth)acrylate, <NUM>-methoxybutylpoly(oxycarbonylmethyl) (meth)acrylate, allylpoly(oxycarbonylmethyl) (meth)acrylate, vinylpoly(oxycarbonylmethyl) (meth)acrylate, methylpoly[<NUM>-(oxypolycarbonyl)ethyl] (meth)acrylate, ethylpoly[<NUM>-(oxypolycarbonyl)ethyl] (meth)acrylate, n-propylpoly[<NUM>-(oxypolycarbonyl)ethyl] (meth)acrylate, isopropylpoly[<NUM>-(oxypolycarbonyl)ethyl] (meth)acrylate, n-butylpoly[<NUM>-(oxypolycarbonyl)ethyl] (meth)acrylate, t-butylpoly[<NUM>-(oxypolycarbonyl)ethyl] (meth)acrylate, methylpoly[α-(oxycarbonyl)benzyl] (meth)acrylate, and ethylpoly[α-(oxycarbonyl)benzyl] (meth)acrylate. Preferably, the examples include methylpoly(oxycarbonylmethyl) (meth)acrylate, ethylpoly(oxycarbonylmethyl) (meth)acrylate, isopropylpoly(oxycarbonylmethyl) (meth)acrylate, n-propylpoly(oxycarbonylmethyl) (meth)acrylate, n-butylpoly(oxycarbonylmethyl) (meth)acrylate, methylpoly[<NUM>-(oxypolycarbonylethyl)] (meth)acrylate, and ethylpoly[<NUM>-(oxypolycarbonylethyl)] (meth)acrylate.

The monomer (b) is an ethylenically unsaturated monomer other than the monomer (a). The monomer (b) can be classified into a monomer (b1) and a monomer (b2), and the monomer (b) used for polymerization of the copolymer A contains one or both of the monomer (b1) and the monomer (b2).

The monomer b1 is represented by general formula (<NUM>).

In general formula (<NUM>), R<NUM> represents a hydrogen atom or a methyl group, and R<NUM> to R<NUM> each represent a branched alkyl group having <NUM> to <NUM> carbon atoms or a phenyl group, which are the same as or different from each other.

The number of the branched alkyl group is, for example, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, and may be in the range between the two values exemplified herein. Examples of the branched alkyl group include an isopropyl group, an isopropenyl group, an isobutyl group, a s-butyl group, a t-butyl group, a <NUM>-ethylpropyl group, a <NUM>-methylbutyl group, a <NUM>-methylpentyl group, a <NUM>,<NUM>-dimethylpropyl group, a <NUM>,<NUM>-dimethylbutyl group, a texyl group, a cyclohexyl group, a <NUM>,<NUM>-dimethylpentyl group, a <NUM>-methylhexyl group, a <NUM>,<NUM>-dimethylhexyl group, a <NUM>-methylheptyl group, a <NUM>-methylbutyl group, a <NUM>-ethylbutyl group, a <NUM>,<NUM>-dimethylpropyl group, a cyclohexylmethyl group, a a2-ethylhexyl group, a <NUM>-propylpentyl group, and a <NUM>-methylpentyl group. Preferred as R<NUM> to R<NUM> are an isopropyl group, an isopropenyl group, a s-butyl group, a t-butyl group, a phenyl group, and a <NUM>-ethylhexyl group, which are the same as or different from each other. Particularly, an isopropyl group and a <NUM>-ethylhexyl group are preferred.

Examples of the monomer (b1) include (meth) acrylate silyl esters such as triisopropylsilyl (meth)acrylate, triisobutylsilyl (meth)acrylate, tri-s-butylsilyl(meth)acrylate, triisopentylsilyl (meth)acrylate, triphenylsilyl (meth)acrylate, diisopropylphenylsilyl (meth)acrylate, diisopropylisobutylsilyl (meth)acrylate, diisopropyl-s-butylsilyl (meth)acrylate, diisopropylisopentylsilyl (meth)acrylate, isopropyldiisobutylsilyl (meth)acrylate, isopropyl di-s-butylsilyl (meth)acrylate, t-butyldiisobutylsilyl (meth)acrylate, t-butyldiisopentylsilane (meth)acrylate, t-butyldiphenylsilyl (meth)acrylate, diisopropylthexylsilyl (meth)acrylate, diisopropylcyclohexylsilyl (meth)acrylate, tricyclohexylsilyl (meth)acrylate, tri-<NUM>,<NUM>-dimethylpentylsilyl (meth)acrylate, tri-<NUM>,<NUM>-dimethylpropylsilyl (meth)acrylate, tricyclohexylmethylsilyl (meth)acrylate, diisopropylcyclohexylmethylsilyl (meth)acrylate, tri-<NUM>-ethylhexylsilyl (meth)acrylate, and tri-<NUM>-propylpentylsilyl (meth)acrylate. These monomers (b1) can be used alone, or two or more of these can be used in combination.

The monomer (b2) is the monomer obtained by removing the monomer (b1) from the monomer (b). In other words, the monomer (b2) is the monomer that is not represented by any of general formulas (<NUM>) to (<NUM>). Examples of the monomer (b2) include (meth)acrylic acid esters, vinyl compounds, aromatic compounds, and dialkyl ester compounds of dibasic acid, which are not represented by general formulas (<NUM>) to (<NUM>). It should be noted that (meth)acrylic acid ester means acrylic acid ester or methacrylic acid ester in the present specification.

Examples of the (meth) acrylic acid ester which is not represented by general formulas (<NUM>) to (<NUM>) include (meth)acrylic acid esters such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, <NUM>-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, <NUM>-methoxyethyl (meth)acrylate, <NUM>-methoxypropyl (meth)acrylate, <NUM>-methoxybutyl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, <NUM>-ethoxyethyl (meth)acrylate, propylene glycol monomethyl (meth)acrylate, <NUM>-hydroxyethyl (meth)acrylate, <NUM>-hydroxypropyl (meth)acrylate, glycidyl (meth)acrylate, furfuryl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, <NUM>-[<NUM>-(<NUM>-hydroxyethoxy)ethoxy]ethyl methacrylate, mono(<NUM>-(meth)acryloyloxyethyl) succinate, N-(<NUM>-dimethylaminopropyl) (meth)acrylamide, <NUM>-hydroxyethyl (meth)acrylate, <NUM>-[<NUM>-(<NUM>-methoxyethoxy)ethoxy]ethyl (meth)acrylate, and N,N'-dimethyl (meth)acrylamide.

Examples of the vinyl compound include vinyl compounds having a functional group such as vinyl chloride, vinylidene chloride, acrylonitrile, methacrylonitrile, vinyl acetate, vinyl benzoate, vinyl butyrate, butyl vinyl ether, lauryl vinyl ether, and N-vinyl pyrrolidone.

Examples of the aromatic compound include styrene, vinyltoluene, and α-methylstyrene.

Examples of the dialkyl ester compound of dibasic acid include dimethyl maleate, dibutyl maleate, and dimethyl fumarate.

In the copolymer A, these monomers (b) can be used alone, or two or more of these can be used in combination. From the viewpoint of the dissolution property of the coating film and the coating film property, the monomer (b) preferably contains (meth)acrylic acid ester of the monomer (b1) or the monomer (b2). From the viewpoint of crack resistance, the monomer (b) preferably contains (meth)acrylic acid ester of the monomer (b2), and more preferably contains methyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, <NUM>-ethylhexyl (meth)acrylate, <NUM>-methoxyethyl (meth)acrylate, <NUM>-ethoxyethyl (meth)acrylate, <NUM>-hydroxyethyl (meth)acrylate, glycidyl (meth)acrylate, furfuryl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate or the like. From the viewpoint of the coating film property, the monomer (b) preferably contains the monomer (b1), and more preferably contains triisopropylsilyl (meth)acrylate, t-butyl diphenylsilyl (meth)acrylate, tri-<NUM>-ethylhexylsilyl (meth)acrylate or the like.

The weight average molecular weight (Mw) of the copolymer A is preferably <NUM> to <NUM>. When the molecular weight is less than <NUM>, the coating film of the antifouling coating becomes weak, thereby prone to peeling and cracking. When the molecular weight exceeds <NUM>, the viscosity of the polymer solution increases, and thus handling becomes difficult. The Mw is, specifically for example, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, and may be in the range between the two values exemplified herein.

As the method of measuring Mw, gel permeation chromatography (GPC method) can be mentioned for example.

The copolymer A may be any of a random copolymer, an alternating copolymer, a periodic copolymer, or a block copolymer of the monomer (a1), the monomer (a2), and the monomer (b).

The copolymer A can be, for example, obtained by polymerizing the monomer (a1), the monomer (a2), and the monomer (b) in the presence of a polymerization initiator.

Examples of the polymerization initiator include azo compounds such as <NUM>,<NUM>'-azobisisobutyronitrile, <NUM>,<NUM>'-azobis(<NUM>-methylbutyronitrile), <NUM>,<NUM>'-azobis(<NUM>,<NUM>-dimethylvaleronitrile), dimethyl-<NUM>,<NUM>'-azobisisobutyrate, and <NUM>,<NUM>'-azobis(N-butyl-<NUM>-methylpropionamide); and peroxides such as benzoyl peroxide, di-tert-butyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxyisopropylcarbonate, t-butyl peroxy-<NUM>-ethylhexanoate, t-hexyl peroxy-<NUM>-ethylhexanoate, di-t-hexylperoxide, t-butyl peroxy-<NUM>-ethylhexyl monocarbonate, di-t-butylperoxide, <NUM>,<NUM>,<NUM>,<NUM>-tetramethylbutyl peroxyneodecanoate, t-amyl peroxyneodecanoate, t-hexyl peroxypivalate, t-amyl peroxypivalate, and <NUM>,<NUM>,<NUM>,<NUM>-tetramethylbutyl peroxy-<NUM>-ethylhexanoate. These polymerization initiators can be used alone, or two or more of these can be used in combination. As the polymerization initiator, <NUM>,<NUM>'-azobisisobutyronitrile, <NUM>,<NUM>'-azobis(<NUM>-methylbutyronitrile), <NUM>,<NUM>'-azobis(<NUM>,<NUM>-dimethylvaleronitrile), dimethyl-<NUM>,<NUM>'-azobisisobutyrate, and <NUM>,<NUM>,<NUM>,<NUM>-tetramethylbutyl peroxy-<NUM>-ethylhexanoate are particularly preferable. By suitably selecting the amount of the polymerization initiator being used, the molecular weight of the copolymer A can be adjusted.

As the polymerization method, liquid polymerization, bulk polymerization, emulsion polymerization, suspension polymerization, non-aqueous dispersion polymerization and the like can be mentioned. Among these, liquid polymerization or non-aqueous dispersion polymerization is preferable since it can synthesize the copolymer A simply and accurately.

In the polymerization reaction, organic solvent can be used as necessary. Here, organic solvent is not particularly limited. Examples of the organic solvent include aromatic hydrocarbon-based solvents such as xylene and toluene; aliphatic hydrocarbon-based solvents; ester-based solvents such as ethyl acetate, butyl acetate, isobutyl acetate, methoxy propyl acetate, and propylene glycol <NUM>-monomethyl ether <NUM>-acetate; alcohol-based solvents such as isopropyl alcohol, butyl alcohol, and propylene glycol monomethyl ether; ether-based solvents such as dioxane, diethyl ether, and dibutyl ether; and ketone-based solvents such as methyl ethyl ketone and methyl isobutyl keton.

Among these, butyl acetate, isobutyl acetate, butyl alcohol, propylene glycol monomethyl ether, propylene glycol <NUM>-monomethylether <NUM>-acetate, toluene, and xylene are preferable. These solvents can be used alone, or two or more of these can be used in combination. The reaction temperature in the polymerization reaction can be suitably controlled depending on the type of the polymerization initiator used and the like. The reaction temperature is usually <NUM> to <NUM>, and preferably <NUM> to <NUM>.

The polymerization reaction is preferably performed under inert gas atmosphere such as nitrogen gas and argon gas.

The copolymer B is a copolymer of the monomer (b1) and the monomer (b2), and contains a monomer unit derived from the monomer (b1) and the monomer (b2). The content of the monomer (b1) to the total of the monomer (b1) and the monomer (b2) is preferably <NUM> to <NUM> mass%, and more preferably <NUM> to <NUM> mass%. The content is, specifically for example, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> mass%, and may be in the range between the two values exemplified herein. In this case, the dissolution property of the coating film is particularly excellent.

As the polymerization method, initiator, solvent, temperature, other conditions, measurement method of Mw, and the like, those mentioned for the copolymer A can be applied.

The content of the copolymer B in the composition of the present invention is not particularly limited. The content ratio with respect to the copolymer A, that is, the mass ratio (the copolymer B/the copolymer A), is usually <NUM> to <NUM>, and preferably <NUM> to <NUM> in terms of solid content. The mass ratio is, for example, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, and may be in the range between the two values exemplified herein.

As the antifouling agent, an inorganic chemical and an organic chemical can be mentioned for example.

As the inorganic chemical, for example, cuprous oxide, cuprous thiocyanate (generic name: copper rhodanide), copper powder and the like can be mentioned. Among these, cuprous oxide and copper rhodanide are preferable. Cuprous oxide is preferably surface-treated with glycerin, sucrose, stearic acid, lauric acid, lecithin, mineral oil and the like in terms of long-term shelf stability.

As the organic chemical, for example, copper <NUM>-mercaptopyridine-N-oxide (generic name: copper pyrithione), zinc <NUM>-mercaptopyridine-N-oxide (generic name: zinc pyrithione), zinc ethylenebis(dithiocarbamate) (generic name: zineb), <NUM>,<NUM>-dichloro-<NUM>-n-octyl-<NUM>-isothiazolone (generic name: Sea-nine <NUM>), <NUM>,<NUM>-dichlorophenyl-N-N-dimethylurea (generic name: Diuron), <NUM>-methylthio-<NUM>-t-butylamino-<NUM>-cyclopropylamino-s-triazine (generic name: Irgarol <NUM>), <NUM>-(p-chlorophenyl)-<NUM>-cyano-<NUM>-bromo-<NUM>-trifluoromethyl pyrrole (generic name: ECONEA <NUM>), <NUM>-[<NUM>-(<NUM>,<NUM>-dimethylphenyl)ethyl]-<NUM>-imidazole (generic name: Medetomidine) and the like can be mentioned.

These antifouling agents can be used alone, or two or more of these can be used in combination.

The content of the antifouling agent in the composition of the present invention is not particularly limited, and usually <NUM> to <NUM> mass% in terms of solid content. The content of the antifouling agent is, for example, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> mass%, and may be in the range between the two values exemplified herein.

Further, the antifouling coating resin of the present invention can further contain a resin component other than copolymers A and B, a release modifier, a plasticizer, a pigment, a dye, an antifoaming agent, a dehydrating agent, a thixotropic agent, an organic solvent and the like as necessary, thereby giving the antifouling coating.

As the other resin component, a polymer P and the like can be mentioned for example.

The polymer P is a polymer which can be obtained by polymerizing the monomer (b2).

In the present invention, one type of the monomer (b2) can be used alone, or two or more types of the monomer (b2) can be used in combination. Particularly, in terms of compatibility with the copolymer A, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, <NUM>-ethylhexyl (meth)acrylate, <NUM>-methoxyethyl (meth)acrylate, <NUM>-ethoxyethyl (meth)acrylate, furfuryl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, benzyl (meth)acrylate, and the like are preferable.

The content of the polymer P in the composition of the present invention is not particularly limited. The content ratio with respect to the copolymer A, that is, the mass ratio (the polymer P/the copolymer A), is usually <NUM> to <NUM>, and preferably <NUM> to <NUM> in terms of solid content. The mass ratio is, for example, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, and may be in the range between the two values exemplified herein.

As the release modifier, for example, rosin, rosin derivative, naphthenic acid, cycloalkenyl carboxylic acid, bicycloalkenyl carboxylic acid, versatic acid, trimethyl isobutenyl cyclohexene carboxylic acid, and metal salts thereof; monocarboxylic acid and salts thereof; and the afore-mentioned alicyclic hydrocarbon resin can be mentioned. These release modifiers can be used alone, or two or more of these can be used in combination.

As the rosin derivative, hydrogenated rosin, disproportionated rosin, maleic acid modified rosin, formylated rosin, polymerized rosin and the like can be exemplified.

As the alicyclic hydrocarbon resin, for example, Quintone <NUM>, Quintone <NUM>, Quintone <NUM> (product name, made by Zeon Corporation) and the like can be mentioned as commercially available product.

Among these, rosin, rosin derivative, naphthenic acid, versatic acid, trimethyl isobutenyl cyclohexene carboxylic acid, and metal salts thereof are preferable.

As the plasticizer, phosphoric acid ester, phthalic acid ester, adipic acid ester, sebacic acid ester, polyester, epoxidized soybean oil, alkyl vinyl ether polymer, polyalkylene glycol, t-nonylpentasulfide, Vaseline, polybutene, tris(<NUM>-ethylhexyl)trimellitate, silicone oil, chlorinated paraffin and the like can be mentioned for example. These plasticizers can be used alone, or two or more of these can be used in combination.

As the dehydrating agent, calcium sulfate, synthetic zeolite-based adsorbent, orthoester, silicate such as tetramethoxysilane and tetraethoxysilane, isocyanate, carbodiimide, carbodimidazole and the like can be mentioned. These can be used alone, or two or more of these can be used in combination.

The antifouling coating composition of the present invention can be produced, for example, by mixing and dispersing a solution mixture containing a copolymer, an antifouling agent, other additives, and the like by use of a disperser.

As the solution mixture, the one obtained by dissolving or dispersing various materials such as the copolymer, the antifouling agent and the like in a solvent is preferable.

As the disperser, for example, the one which can be used as a micro-pulverizer can be suitably used. For example, a commercially available homo mixer, a sand mill, a bead mill, a disper and the like can be used. Furthermore, the solution mixture may be mixed and dispersed by using a stirrer-equipped container containing glass beads for mixing and dispersing.

In the method of antifouling treatment according to the present invention, an antifouling coating film is formed by coating with the above-mentioned antifouling coating composition the surface of an object on which the coating film is to be formed. The method of antifouling treatment according to the present invention can prevent adhesion of aquatic fouling organisms by the gradual dissolution of the surface of the antifouling coating film such that the surface of the coating film is continually renewed.

Examples of the object on which the coating film is to be formed include ships (in particular, ship bottoms), fishing tools, and structures submerged in seawater.

The thickness of the antifouling coating film can be suitably selected depending on the type of the object on which the coating film is to be formed, the navigation speed of a ship, the seawater temperature and the like. For example, when the object on which the coating film is to be formed is a ship bottom, the thickness of the antifouling coating film is usually <NUM> to <NUM>, and preferably <NUM> to <NUM>.

Examples and the like are provided hereinafter to further clarify characteristics of the present invention. The present invention, however, is not limited to these Examples and the like.

In each of Production Examples, Examples, and Comparative Examples, "%" denotes "mass%". The weight average molecular weight (Mw) is a value determined by gel permeation chromatography (GPC) (a polystyrene conversion value). The conditions for GPC are as follows.

The non-volatile matter content is a value measured in accordance with JIS K <NUM>-<NUM>-<NUM>:<NUM> (ISO <NUM>:<NUM>) "testing methods for paint components - non-volatile matter content".

<NUM> (<NUM> mol) of methyl chloroacetate, <NUM> (<NUM> mol) of acrylic acid, <NUM> of <NUM>-methoxyphenol, and <NUM> of ethyl acetate were charged to a four-necked flask equipped with a thermometer, a condenser, a stirrer, and a dropping funnel, and <NUM> (<NUM> mol) of triethylamine was dropped with stirring while keeping the temperature at <NUM> or below. After completion of dropping, the reaction mixture was stirred for <NUM> hours at <NUM> to <NUM>. After completion of the reaction, the organic layer was washed with city water, hydrochloric acid solution, and sodium bicarbonate solution in this order. Subsequently, the solvent was removed by condensation under reduced pressure, thereby obtaining <NUM> of the monomer a1-<NUM>.

Raw materials shown in Table <NUM> were used, and the reaction was performed by procedures similar to those of Production Example <NUM>, thereby obtaining the monomers a1-<NUM> to a1-<NUM>. Reaction conditions and yields of Production Examples <NUM> to <NUM> are shown in Table <NUM>.

<NUM> (<NUM> mol) of sodium monochloroacetate, <NUM> (<NUM> mol) of methyl chloroacetate, and <NUM> of N-methyl-<NUM>-pyrrolidone were charged to a four-necked flask equipped with a thermometer, a condenser, and a stirrer, and the mixture was stirred for <NUM> hours at <NUM> to <NUM>. After completion of the reaction, <NUM> of toluene was charged to the reaction solution, and then the organic layer was washed with city water, hydrochloric acid solution, and sodium bicarbonate solution in this order. Subsequently, the solvent was removed by condensation under reduced pressure, thereby obtaining <NUM> of methoxycarbonylmethyl chloroacetate.

Subsequently, <NUM> (<NUM> mol) of methoxycarbonylmethyl chloroacetate as the product material of the first reaction, <NUM> (<NUM> mol) of acrylic acid, <NUM> of <NUM>-methoxyphenol, and <NUM> of ethyl acetate were charged to a four-necked flask equipped with a thermometer, a condenser, a stirrer, and a dropping funnel, and <NUM> (<NUM> mol) of triethylamine was dropped with stirring while keeping the temperature at <NUM> or below. After completion of dropping, the reaction mixture was stirred for <NUM> hours at <NUM> to <NUM>. After completion of the reaction, the organic layer was washed with city water, hydrochloric acid solution, and sodium bicarbonate solution in this order. Subsequently, the solvent was removed by condensation under reduced pressure, thereby obtaining <NUM> of the monomer a2-<NUM>.

Raw materials shown in Tables <NUM> to <NUM> were used, and the reaction was performed by procedures similar to those of Production Example <NUM>, thereby obtaining the monomers a2-<NUM> to a2-<NUM> shown in Table <NUM>. Reaction conditions and yields of Production Examples <NUM> to <NUM> are shown in Tables <NUM> to <NUM>.

Details of the raw materials shown in Tables <NUM> to <NUM> are as follows.

As solvent, <NUM> of xylene and <NUM> of propylene glycol monomethyl ether were charged to a four-necked flask equipped with a thermometer, a condenser, a stirrer, and a dropping funnel, followed by introduction of nitrogen gas, and then the mixture was maintained at <NUM> with stirring. To the solvent mixture, a mixture of the monomers (a) and (b) having the blending amount (g) shown in Table <NUM>, and <NUM> (initial addition) of <NUM>,<NUM>,<NUM>,<NUM>-tetramethylbutyl peroxy-<NUM>-ethylhexanoate as polymerization initiator was dropped for <NUM> hours while maintaining the reaction mixture at <NUM>. Subsequently, after stirring for <NUM> hour at <NUM>, <NUM> of <NUM>,<NUM>,<NUM>,<NUM>-tetramethylbutyl peroxy-<NUM>-ethylhexanoate was added every <NUM> hour for three times, followed by stirring for <NUM> hours at the same temperature. Then, the reaction mixture was cooled to room temperature to obtain the copolymer solution A-<NUM>. Non-volatile matter content and Mw of A-<NUM> are shown in Table <NUM>.

Except for the usage of the monomer and the solvent as shown in Tables <NUM> to <NUM>, the polymerization reaction was performed by procedures similar to those of Production Example P1, thereby obtaining the copolymer solutions A-<NUM> to A-<NUM>, B1 to B3, and C-<NUM> to C-<NUM>. Non-volatile matter content and Mw of each polymer are shown in Tables <NUM> to <NUM>. The units of the numerical values of the blending amount of the raw materials in Tables are g.

<NUM> of gum rosin made in China (WW) and <NUM> of xylene were charged to a flask equipped with a thermometer, a reflux condenser, and a stirrer. Thereafter, the reaction mixture was dehydrated under reflux under reduced pressure for <NUM> hour at <NUM> to <NUM> to obtain a xylene solution of gum rosin (brown transparent liquid, <NUM>% solid content). The non-volatile matter content of the solution obtained was <NUM>%.

<NUM> of gum rosin made in China (WW) and <NUM> of xylene were charged to a flask equipped with a thermometer, a reflux condenser, and a stirrer, and <NUM> of zinc oxide was further added such that all of the resin acid in the rosin form zinc salt. The reaction mixture was dehydrated under reflux under reduced pressure for <NUM> hours at <NUM> to <NUM>. Then, the reaction mixture was cooled and filtered to obtain a xylene solution of gum rosin zinc salt (dark brown transparent liquid, <NUM>% solid content). The non-volatile matter content of the solution obtained was <NUM>%.

A xylene solution of hydrogenated rosin zinc salt (dark brown transparent liquid, <NUM>% solid content) was obtained in the same way as in Production Example D2, except for replacing the gum rosin made in China (WW) in Production Example D2 with hydrogenated gum rosin.

The components shown in Tables <NUM> to <NUM> were blended by the ratio (mass%) shown in the same Tables, and were mixed and dispersed with glass beads having a diameter of <NUM> to <NUM>, thereby producing the coating composition.

Details of the components in Tables are as follows.

Hydrogenated rosin zinc salt solution: The one produced in Production Example D3 was used.

Gum rosin zinc salt solution: The one produced in Production Example D2 was used.

Gum rosin solution: The one produced in Production Example D1 was used.

The following tests were performed for the coating compositions of Examples and Comparative Examples. Evaluation results are shown in Tables <NUM> to <NUM>.

In all Comparative Examples, the result of at least one of the rotary test and the antifouling test was not satisfactory.

A tank was provided, in the center thereof, with a rotating drum having a diameter of <NUM> and a height of <NUM> to allow the rotation of the drum by a motor. The tank was also provided with a cooling apparatus for keeping the temperature of seawater constant, and an automatic pH controller for keeping the pH of the seawater constant.

Test plates were prepared in accordance with the following method.

First, an anti-corrosive coating film was formed by applying an anti-corrosive coating material (an epoxy vinyl-based A/C) onto a titanium plate (<NUM> x <NUM> x <NUM>) such that the thickness after drying would be about <NUM>, followed by drying. Then, coating compositions obtained in Examples and Comparative Examples were applied such that the thickness after drying would be about <NUM>. The applied coating was dried for <NUM> days at <NUM>, thereby preparing the test plates.

The prepared test plates were fixed to the rotating drum of the rotary apparatus of the above-mentioned equipment to contact with the seawater, and the rotating drum was rotated at a speed of <NUM> knots. During the test, the temperature and the pH of the seawater were maintained at <NUM> and at <NUM> to <NUM>, respectively, and the seawater was replaced once every two weeks.

Initial film thickness and remaining film thickness were measured every <NUM> months for each of the test plates, using a shape measurement laser microscope VK-X100 (made by KEYENCE CORPORATION). The thickness of the dissolved coating film was calculated from the difference between the two values, thereby obtaining the average dissolution amount of the coating film per one month (µm/month). Further, when measuring the remaining film thickness after <NUM> months in the rotary test, the surface of each coating film was observed with naked eye and with a microscope to evaluate the surface condition of the coating film.

Evaluations of the surface conditions of the coating films were performed under the following criteria.

Each of the coating compositions obtained in Examples and Comparative Examples was applied onto both surfaces of a hard vinyl chloride plate (<NUM> x <NUM> x <NUM>) such that the thickness of a dried coating film would be about <NUM>. The applied coating obtained was dried for <NUM> days at room temperature (<NUM>), and the test plate having the dried coating film with a thickness of about <NUM> was prepared. This test plate was immersed at <NUM> below sea level in Owase City, Mie Prefecture, Japan, and the test plate fouling due to attached objects was examined after <NUM> months and <NUM> months.

Claim 1:
An antifouling coating composition containing a copolymer A and an antifouling agent, wherein:
the copolymer A is a copolymer of a monomer (a) and an ethylenically unsaturated monomer (b) other than the monomer (a);
the monomer (a) is constituted of a monomer (a1) and a monomer (a2);
the monomer (a1) is represented by general formula (<NUM>);
the monomer (a2) is represented by general formula (<NUM>);
a content of the monomer (a1) in the monomer (a) is <NUM> to <NUM> mass%;
<CHM>
in general formula (<NUM>), R<NUM> represents a hydrogen atom or a methyl group, R<NUM> represents a hydrogen atom, a methyl group, or a phenyl group, and R<NUM> represents an alkyl group which may be substituted with an alkoxy group having <NUM> to <NUM> carbon atoms or a phenyl group, or a phenyl group, the alkyl group having <NUM> to <NUM> carbon atoms; and
<CHM>
in general formula (<NUM>), R<NUM> represents a hydrogen atom or a methyl group, R<NUM> represents a hydrogen atom, a methyl group, or a phenyl group, R<NUM> represents an alkyl group which may be substituted with an alkoxy group having <NUM> to <NUM> carbon atoms or a phenyl group, or a phenyl group, the alkyl group having <NUM> to <NUM> carbon atoms, and n represents an integer of <NUM> to <NUM>.