Resin composition

Abstract

This resin composition comprises: a (meth)acrylic copolymer including a structural unit (A) based on a specific metal atom-containing polymerizable monomer (a) and a structural unit (B) based on a specific polysiloxane block-containing polymerizable monomer (b); and an organic solvent. With respect to the total mass of all structural units forming the (meth)acrylic copolymer, the contained amount of the structural unit (A) is 5-35 mass%, the contained amount of the structural unit (B) is 35-75 mass%, and the contained amount of structural units based on (meth)acrylic macromonomers is less than 13 mass%. The (meth)acrylic copolymer has a weight average molecular weight of 2000-6500. The resin composition has a VOC content of 500 g / L or less.

Description

resin composition

[0001] The present invention relates to a resin composition. This application claims priority to Japanese Patent Application No. 2023-138774, filed on August 29, 2023, the contents of which are incorporated herein by reference.

[0002] It is known that antifouling paints are applied to marine structures and ships to prevent the adhesion of marine organisms, which can cause corrosion of parts in contact with seawater and reduce navigation speed. Self-polishing antifouling paints are known as antifouling paints. Self-polishing antifouling paints typically contain a hydrolyzable resin and an antifouling agent. The coating film obtained from such an antifouling paint exhibits a long-term antifouling effect by gradually dissolving the coating film surface in seawater, thereby renewing the surface (self-polishing), and constantly exposing the antifouling agent to the coating film surface.

[0003] The following have been proposed as self-polishing antifouling paints: A paint composition containing a copolymer containing structural units based on a metal atom-containing polymerizable monomer containing a divalent metal atom (Patent Document 1). A paint composition containing a copolymer containing structural units based on a silicon-containing polymerizable monomer and structural units based on a metal atom-containing polymerizable monomer containing a divalent metal atom (Patent Document 2).

[0004] JP 2002-012630 A JP 2004-300410 A

[0005] When the coating composition described in Patent Document 1 does not contain an antifouling agent, the coating film formed by the coating composition sometimes exhibits insufficient antifouling effect. When the coating composition described in Patent Document 2 does not contain an antifouling agent, the coating film formed by the coating composition exhibits excellent antifouling effect. However, when the coating composition contains an organic solvent in addition to the copolymer, the coating composition has poor storage stability and is prone to thickening over time during storage. While it is possible to reduce the viscosity by further adding an organic solvent to the coating composition, this increases the VOC (volatile organic compound) content. Meanwhile, a coating composition with antifouling properties is also required to have excellent transparency from the perspective of appearance.

[0006] An object of the present invention is to provide a resin composition which can form a coating film exhibiting excellent transparency and antifouling effect, which is resistant to thickening during storage, and which has excellent storage stability.

[0007] The present invention has the following aspects: [1] A resin composition comprising: a (meth)acrylic copolymer containing a structural unit (A) based on a metal atom-containing polymerizable monomer (a) containing an ethylenically unsaturated bond and a structure represented by the following formula (1) or (2), and a structural unit (B) based on at least one polysiloxane block-containing polymerizable monomer (b) selected from the group consisting of a polymerizable monomer represented by the following formula (b1), a polymerizable monomer represented by the following formula (b2), a polymerizable monomer represented by the following formula (b3), and a polymerizable monomer represented by the following formula (b4), and an organic solvent, wherein the content of the structural unit (A) is 5 to 35 mass%, the content of the structural unit (B) is 35 to 75 mass%, and the content of the structural unit based on a (meth)acrylic macromonomer is less than 13 mass%, relative to the total mass of all structural units constituting the (meth)acrylic copolymer, and the weight-average molecular weight of the (meth)acrylic copolymer is 2,000 or more and 6,500 or less, A resin composition having a VOC content of 500 g / L or less. ０ ... (2) CH ２ =CR ３ａ -CO-O-(C ｕ H ２ｕ -O) ｖ -C ｗ H ２ｗ -(SiR ３ｂ R ３ｃ -O) ｘ -SiR ３ｄ R ３ｅ R ３ｆ ... (b1) CH ２ =CR ４ａ -CO-O-(C ｕ’ H ２ｕ’ -O) ｖ’ -C ｗ’ H ２ｗ’ -Si(OSiR ４ｂ R ４ｃ R ４ｄ ) ３ ... (b2) CH２ =CR ２ａ -CO-O-(C ｋ’ H ２ｋ’ -O) ｌ’ -C ｍ’ H ２ｍ’ -Si((OSiR ２ｂ R ２ｃ ) ｒ -OSiR ２ｄ R ２ｅ R ２ｆ ) ２ -OSi((OSiR ２ｇ R ２ｈ ) ｓ -OSiR ２ｉ R ２ｊ R ２ｋ ) ２ -C о’ H ２о’ -(O-C ｐ’ H ２ｐ’ ) ｑ’ -O-CO-CR ２ｌ =CH ２ ... (b3) CH ２ =CR １ａ -CO-O-(C ｋ H ２ｋ -O) ｌ -C ｍ H ２ｍ -(SiR １ｂ R １ｃ -O) ｎ -SiR １ｄ R １ｅ -C о H ２о -(O-C ｐ H ２ｐ ) ｑ -O-CO-CR １ｆ =CH ２ ...(b4) (wherein M represents Zn, Cu, Mg, or Ca, and R ０ represents a monovalent organic acid residue, R ３ａ represents a hydrogen atom or a methyl group, u represents an integer of 2 to 5, v represents a number of 0 to 50, w represents an integer of 2 to 5, x represents a number of 3 to 80, and R ３ｂ ~R ３ｆ each independently represents an alkyl group, an alkoxy group, a phenyl group, a substituted phenyl group, a phenoxy group, or a substituted phenoxy group; R ４ａrepresents a hydrogen atom or a methyl group, u' represents an integer of 2 to 5, v' represents a number of 0 to 50, w' represents an integer of 2 to 5, and R ４ｂ ~R ４ｄ are each independently an alkyl group, —(OSiR ５１ R ５２ ) ｙ -OSiR ５３ R ５４ R ５５ (where y is an integer from 0 to 20, R ５１ ~R ５５ represents an alkyl group, or —R ５６ - (OC ２ H ４ ) ｙ’ -OR ５７ (where y' represents an integer of 1 to 20, and R ５６ represents an alkylene group, and R ５７ represents an alkyl group; ２ａ and R ２ｌ each independently represents a hydrogen atom or a methyl group; k' and p' each independently represents an integer of 2 to 5; l' and q' each independently represents a number of 0 to 50; m' and o' each independently represents an integer of 2 to 5; r and s each independently represents a number of 0 to 20; R ２ｂ ~R ２ｋ each independently represents an alkyl group, R １ａ and R １ｆ each independently represents a hydrogen atom or a methyl group; k and p each independently represents an integer of 2 to 5; l and q each independently represents a number of 0 to 50; m and o each independently represents an integer of 2 to 5; n represents a number of 3 to 80; R １ｂ ~R １ｅeach independently represent an alkyl group, an alkoxy group, a phenyl group, a substituted phenyl group, a phenoxy group, or a substituted phenoxy group. [2] The resin composition according to [1], wherein the content of the (meth)acrylic copolymer is 10 to 65 mass % relative to the total mass of the resin composition. [3] A resin composition comprising: a (meth)acrylic copolymer including a structural unit (A) based on a metal atom-containing polymerizable monomer (a) having a structure represented by the following formula (1) or (2) and an ethylenically unsaturated bond, and a structural unit (B) based on at least one polysiloxane block-containing polymerizable monomer (b) selected from the group consisting of a polymerizable monomer represented by the following formula (b1), a polymerizable monomer represented by the following formula (b2), a polymerizable monomer represented by the following formula (b3), and a polymerizable monomer represented by the following formula (b4); and an organic solvent, wherein the content of the structural unit (A) is 5 to 35 mass%, the content of the structural unit (B) is 35 to 75 mass%, and the content of the structural unit based on a (meth)acrylic macromonomer is less than 13 mass%, relative to the total mass of all structural units constituting the (meth)acrylic copolymer, and the weight average molecular weight of the (meth)acrylic copolymer is 2,000 or more and 6,500 or less, A resin composition, wherein the content of the organic solvent is 50% by mass or less relative to the total mass of the resin composition, and the viscosity measured by a Gardner bubble viscometer at 25°C and a solid content concentration of 50% by mass is Z or less. ０ ... (2) CH ２ =CR ３ａ -CO-O-(C ｕ H ２ｕ -O) ｖ -C ｗ H ２ｗ -(SiR ３ｂ R ３ｃ -O) ｘ -SiR ３ｄ R ３ｅ R ３ｆ ... (b1) CH ２ =CR ４ａ -CO-O-(C ｕ’ H ２ｕ’ -O) ｖ’ -C ｗ’ H ２ｗ’-Si(OSiR ４ｂ R ４ｃ R ４ｄ ) ３ ... (b2) CH ２ =CR ２ａ -CO-O-(C ｋ’ H ２ｋ’ -O) ｌ’ -C ｍ’ H ２ｍ’ -Si((OSiR ２ｂ R ２ｃ ) ｒ -OSiR ２ｄ R ２ｅ R ２ｆ ) ２ -OSi((OSiR ２ｇ R ２ｈ ) ｓ -OSiR ２ｉ R ２ｊ R ２ｋ ) ２ -C о’ H ２о’ -(O-C ｐ’ H ２ｐ’ ) ｑ’ -O-CO-CR ２ｌ =CH ２ ... (b3) CH ２ =CR １ａ -CO-O-(C ｋ H ２ｋ -O) ｌ -C ｍ H ２ｍ -(SiR １ｂ R １ｃ -O) ｎ -SiR １ｄ R １ｅ -C о H ２о -(O-C ｐ H ２ｐ ) ｑ -O-CO-CR １ｆ =CH ２ ...(b4) (wherein M represents Zn, Cu, Mg, or Ca, and R ０ represents a monovalent organic acid residue, R ３ａ represents a hydrogen atom or a methyl group, u represents an integer of 2 to 5, v represents a number of 0 to 50, w represents an integer of 2 to 5, x represents a number of 3 to 80, and R ３ｂ ~R ３ｆeach independently represents an alkyl group, an alkoxy group, a phenyl group, a substituted phenyl group, a phenoxy group, or a substituted phenoxy group; R ４ａ represents a hydrogen atom or a methyl group, u' represents an integer of 2 to 5, v' represents a number of 0 to 50, w' represents an integer of 2 to 5, and R ４ｂ ~R ４ｄ are each independently an alkyl group, —(OSiR ５１ R ５２ ) ｙ -OSiR ５３ R ５４ R ５５ (where y is an integer from 0 to 20, R ５１ ~R ５５ represents an alkyl group, or —R ５６ - (OC ２ H ４ ) ｙ’ -OR ５７ (where y' represents an integer of 1 to 20, and R ５６ represents an alkylene group, and R ５７ represents an alkyl group; ２ａ and R ２ｌ each independently represents a hydrogen atom or a methyl group; k' and p' each independently represents an integer of 2 to 5; l' and q' each independently represents a number of 0 to 50; m' and o' each independently represents an integer of 2 to 5; r and s each independently represents a number of 0 to 20; R ２ｂ ~R ２ｋ each independently represents an alkyl group, R １ａ and R １ｆ each independently represents a hydrogen atom or a methyl group; k and p each independently represents an integer of 2 to 5; l and q each independently represents a number of 0 to 50; m and o each independently represents an integer of 2 to 5; n represents a number of 3 to 80; R １ｂ ~R １ｅ each independently represents an alkyl group, an alkoxy group, a phenyl group, a substituted phenyl group, a phenoxy group, or a substituted phenoxy group.

[0008] According to the present invention, it is possible to provide a resin composition which can form a coating film that exhibits excellent transparency and antifouling effect, is resistant to thickening during storage, and has excellent storage stability.

[0009] The following describes specific embodiments of the present invention. However, the present invention is not limited to the following embodiments and can be practiced with various modifications within the scope of the gist. In this specification and claims, a numerical range expressed as "to" means a numerical range including the numerical values ​​before and after "to" as the lower and upper limits. For example, A to B is synonymous with A or more and B or less. The following definitions of terms apply throughout this specification and claims. "(Meth)acrylic copolymer" refers to a copolymer in which at least some of the structural units are derived from (meth)acrylic monomers. A (meth)acrylic copolymer may further contain structural units derived from monomers other than (meth)acrylic monomers (e.g., vinyl monomers such as styrene). "Structural unit" refers to a structural unit derived from a monomer formed by polymerization of a monomer, or a structural unit in which a portion of the structural unit is converted to a different structure by processing the polymer. "Monomer" refers to a polymerizable compound (polymerizable monomer). "(Meth)acrylic monomer" refers to a monomer having a (meth)acryloyl group. "(Meth)acryloyl group" is a general term for acryloyl group and methacryloyl group. "(Meth)acrylate" is a general term for acrylate and methacrylate. "(Meth)acrylic acid" is a general term for acrylic acid and methacrylic acid. "(Meth)acrylonitrile" is a general term for acrylonitrile and methacrylonitrile. "(Meth)acrylamide" is a general term for acrylamide and methacrylamide. "(Meth)acrylic macromonomer" is a general term for acrylic macromonomer and methacrylic macromonomer, and refers to a macromonomer containing a structural unit derived from a (meth)acrylic monomer. "VOC" refers to an organic compound (volatile organic compound) that easily volatilizes at room temperature and normal pressure. Room temperature and normal pressure refers to 10°C to 30°C and 1000 Pa to 1050 Pa.

[0010] [Resin composition (1)] A resin composition according to one embodiment of the present invention (hereinafter also referred to as "resin composition (1)") contains a specific (meth)acrylic copolymer (hereinafter also referred to as "copolymer (X)") and an organic solvent. The copolymer (X) contained in the resin composition (1) may be one type or two or more types. The same applies to the organic solvent. The resin composition (1) may further contain other components other than the copolymer (X) and the organic solvent, as necessary.

[0011] <Copolymer (X)> Copolymer (X) contains a structural unit (A) based on a metal atom-containing polymerizable monomer (a) (hereinafter also referred to as "monomer (a)") and a structural unit (B) based on a polysiloxane block-containing polymerizable monomer (b) (hereinafter also referred to as "monomer (b)"). If necessary, copolymer (X) may further contain a structural unit (hereinafter also referred to as "structural unit (C)") based on a polymerizable monomer other than monomer (a) and monomer (b) (hereinafter also referred to as "monomer (c)").

[0012] (Structural Unit (A)) The monomer (a) contains a structure represented by the following formula (1) or (2) (hereinafter also referred to as "Structure (I)") and an ethylenically unsaturated bond (polymerizable carbon-carbon double bond): -CO-O-M-O-CO- (1) -CO-O-M-R ０ ... (2) where M represents Zn, Cu, Mg, or Ca, and R ０ represents a monovalent organic acid residue.

[0013] In formulas (1) and (2), O or R adjacent to M ０ is ionic bonded to M. When copolymer (X) has structure (I) (a carboxylate structure ionic bonded to M), a coating film containing copolymer (X) exhibits self-polishing properties.

[0014] As M, Zn or Cu is preferred, and Zn is more preferred, in terms of improving the water resistance of the coating film.

[0015] R ０The organic acid residue of R refers to the portion remaining after removing one proton from an organic acid (for example, the portion remaining after removing one proton from the carboxy group of a carboxylic acid), and is ionic bonded to M in place of this proton. Preferred organic acids include carboxylic acids, such as monochloroacetic acid, monofluoroacetic acid, acetic acid, propionic acid, octylic acid, versatic acid, isostearic acid, palmitic acid, cresotic acid, α-naphthoic acid, β-naphthoic acid, benzoic acid, 2,4,5-trichlorophenoxyacetic acid, 2,4-dichlorophenoxyacetic acid, quinolinecarboxylic acid, nitrobenzoic acid, nitronaphthalenecarboxylic acid, pyruvic acid, naphthenic acid, abietic acid, hydrogenated abietic acid, and (meth)acrylic acid. Among these, versatic acid and (meth)acrylic acid are more preferred. ０ In terms of storage stability, organic acid residues other than a (meth)acryloyloxy group are preferred.

[0016] The structural unit (A) has a structure in which the ethylenically unsaturated bond of the monomer (a) is cleaved to form a single bond. The structural unit (A) is preferably at least one selected from the group consisting of the structural unit (A1) represented by the following formula (11) and the structural unit (A2) represented by the following formula (21).

[0017]

[0018] Here, M represents Zn, Cu, Mg, or Ca, and R １ ~R ３ each independently represents a hydrogen atom or a methyl group, R ３２ represents a monovalent organic acid residue. ３２ is R ０ is the same as:

[0019] An example of the monomer that forms the structural unit (A1) is the monomer (a1) represented by the following formula (1). An example of the monomer that forms the structural unit (A2) is the monomer (a2) represented by the following formula (2). CH ２ = C(R １ )-CO-O-M-O-CO-C(R ２ ) = CH ２ ... (1) CH２ = C(R ３ )-CO-O-M-R ３２ ... (2) M, R １ ~R ３ , R ３２ are as described above.

[0020] Specific examples of the monomer (a1) include the following: zinc acrylate [(CH ２ =CHCOO) ２ Zn], zinc methacrylate [(CH ２ =C(CH ３ ) COO) ２ Zn], copper acrylate [(CH ２ =CHCOO) ２ Cu], copper methacrylate [(CH ２ =C(CH ３ ) COO) ２ Cu], magnesium acrylate [(CH ２ =CHCOO) ２ Mg], magnesium methacrylate [(CH ２ =C(CH ３ ) COO) ２ Mg], calcium acrylate [(CH ２ =CHCOO) ２ Ca], calcium methacrylate [(CH ２ =C(CH ３ ) COO) ２ Ca], etc. Among the above, zinc acrylate, zinc methacrylate, copper acrylate, and copper methacrylate are preferred from the viewpoint of the water resistance of the coating film containing copolymer (X). Any one of these monomers may be used alone, or two or more may be used in combination.

[0021] Monomer (a1) can be obtained, for example, by reacting an inorganic metal compound containing a metal element corresponding to M in formula (1) with (meth)acrylic acid in a diluent such as an organic solvent or a reactive diluent having a polymerizable unsaturated group such as an ethylenically unsaturated monomer. The mixture containing the metal-containing polymerizable monomer obtained by this method has excellent compatibility with organic solvents and other monomers, allowing for easy polymerization. The reaction is preferably carried out in the presence of water, and the water content in the reaction mixture is preferably in the range of 0.01 to 30% by mass. Examples of the inorganic metal compound include oxides, hydroxides, and chlorides of metals selected from Zn, Cu, Mg, and Ca.

[0022] Specific examples of the monomer (a2) include the following: metal monochloroacetate (meth)acrylates such as magnesium monochloroacetate (meth)acrylate, calcium monochloroacetate (meth)acrylate, zinc monochloroacetate (meth)acrylate, and copper monochloroacetate (meth)acrylate; metal monofluoroacetate (meth)acrylates such as magnesium monofluoroacetate (meth)acrylate, calcium monofluoroacetate (meth)acrylate, zinc monofluoroacetate (meth)acrylate, and copper monofluoroacetate (meth)acrylate; magnesium acetate (meth)acrylate; metal acetate (meth)acrylates such as magnesium propionate (meth)acrylate, calcium propionate (meth)acrylate, zinc propionate (meth)acrylate, and copper propionate (meth)acrylate; metal propionate (meth)acrylates such as magnesium octoate (meth)acrylate, calcium octoate (meth)acrylate, and zinc octoate (meth)acrylate metal octylate (meth)acrylates such as magnesium versatate (meth)acrylate, calcium versatate (meth)acrylate, zinc versatate (meth)acrylate, copper versatate (meth)acrylate; metal versatate (meth)acrylates such as magnesium versatate (meth)acrylate, calcium isostearate (meth)acrylate, zinc isostearate (meth)acrylate, copper isostearate (meth)acrylate metal isostearate (meth)acrylates such as magnesium palmitate (meth)acrylate, calcium palmitate (meth)acrylate, zinc palmitate (meth)acrylate, and copper palmitate (meth)acrylate; metal cresotate (meth)acrylates such as magnesium cresotate (meth)acrylate, calcium cresotate (meth)acrylate, zinc cresotate (meth)acrylate, and copper cresotate (meth)acrylate;Metal α-naphthoates (meth)acrylates such as magnesium α-naphthoate (meth)acrylate, calcium α-naphthoate (meth)acrylate, zinc α-naphthoate (meth)acrylate, and copper α-naphthoate (meth)acrylate; metal β-naphthoates (meth)acrylates such as magnesium β-naphthoate (meth)acrylate, calcium β-naphthoate (meth)acrylate, zinc β-naphthoate (meth)acrylate, and copper β-naphthoate (meth)acrylate; magnesium benzoate (meth)acrylate, calcium benzoate metal benzoates such as 2,4,5-trichlorophenoxyacetic acid magnesium (meth)acrylate, 2,4,5-trichlorophenoxyacetic acid calcium (meth)acrylate, 2,4,5-trichlorophenoxyacetic acid zinc (meth)acrylate, and 2,4,5-trichlorophenoxyacetic acid copper (meth)acrylate; metal 2,4,5-trichlorophenoxyacetic acid (meth)acrylates such as 2,4-dichlorophenoxyacetic acid magnesium (meth)acrylate, 2,4,5-trichlorophenoxyacetic acid calcium (meth)acrylate, 2,4,5-trichlorophenoxyacetic acid zinc (meth)acrylate, and 2,4,5-trichlorophenoxyacetic acid copper (meth)acrylate; 2,4-dichlorophenoxyacetic acid metal (meth)acrylates such as quinolinecarboxylate magnesium (meth)acrylate, quinolinecarboxylate calcium (meth)acrylate, quinolinecarboxylate zinc (meth)acrylate, and quinolinecarboxylate copper (meth)acrylate; quinolinecarboxylate metal (meth)acrylates such as quinolinecarboxylate magnesium (meth)acrylate, quinolinecarboxylate calcium (meth)acrylate, quinolinecarboxylate zinc (meth)acrylate, and quinolinecarboxylate copper (meth)acrylate; Metal nitrobenzoates (meth)acrylates such as magnesium nitrobenzoate, calcium nitrobenzoate (meth)acrylate, zinc nitrobenzoate (meth)acrylate, and copper nitrobenzoate (meth)acrylate; metal nitronaphthalenecarboxylates (meth)acrylates such as magnesium nitronaphthalenecarboxylate, calcium nitronaphthalenecarboxylate, zinc nitronaphthalenecarboxylate (meth)acrylate, and copper nitronaphthalenecarboxylate (meth)acrylate;Metal pyruvate (meth)acrylates such as magnesium pyruvate (meth)acrylate, calcium pyruvate (meth)acrylate, zinc pyruvate (meth)acrylate, and copper pyruvate (meth)acrylate. Among these, from the viewpoint of the water resistance of the coating film containing the copolymer (X), a monomer in which M is Zn or Cu is preferred. Any one of these monomers may be used alone, or two or more may be used in combination.

[0023] The monomer (a2) is, for example, a compound obtained by mixing an inorganic metal compound containing a metal element corresponding to M in the formula (2), (meth)acrylic acid, and an organic acid residue R ３２ and an organic acid corresponding to the above in a diluent such as an organic solvent or a reactive diluent having a polymerizable unsaturated group such as an ethylenically unsaturated monomer. Examples of the inorganic metal compound include the same inorganic metal compounds as those used to obtain the monomer (a1).

[0024] The copolymer (X) may also contain the structural unit (A1) and the structural unit (A2). That is, the copolymer (X) may also contain a structural unit based on the monomer (a1) and a structural unit based on the monomer (a2).

[0025] When copolymer (X) contains structural units (A1) and (A2), the molar ratio of structural units (A1) to structural units (A2) in copolymer (X) is preferably structural unit (A1) / structural unit (A2) = 10 / 90 to 90 / 10, more preferably 20 / 80 to 80 / 20, and even more preferably 30 / 70 to 70 / 30. If this molar ratio is below the upper limit, the viscosity of the resin composition containing copolymer (X) and an organic solvent tends to decrease, while if it is above the lower limit, the self-polishing properties of the coating film containing copolymer (X) tend to be maintained over a long period of time.

[0026] When the copolymer (X) contains a structural unit based on the monomer (a1) and a structural unit based on the monomer (a2), a monomer mixture containing the monomer (a1) and the monomer (a2) may be used to produce the copolymer (X).

[0027] The monomer mixture containing the monomer (a1) and the monomer (a2) may be, for example, an inorganic metal compound containing a metal element corresponding to M in the formula (1) or the formula (2), (meth)acrylic acid, and an organic acid residue R ３２ and an organic acid corresponding to the above in a diluent such as an organic solvent or a reactive diluent such as an ethylenically unsaturated monomer.

[0028] At that time, R ３２ The amount of organic acid used corresponding to the above is preferably 0.01 to 3 times by mole, more preferably 0.01 to 0.95 times by mole, and even more preferably 0.1 to 0.7 times by mole, relative to the inorganic metal compound. When the organic acid content is 0.01 times by mole or more, solid precipitation is suppressed in the production process of this monomer mixture, and the self-polishing properties and crack resistance of the resulting coating film are improved. When the organic acid content is 3 times by mole or less, the stain-resistant properties of the resulting coating film tend to be maintained for a longer period of time.

[0029] (Structural Unit (B)) The monomer (b) is at least one selected from the group consisting of a polymerizable monomer represented by the following formula (b1) (hereinafter also referred to as "monomer (b1)"), a polymerizable monomer represented by the following formula (b2) (hereinafter also referred to as "monomer (b2)"), a polymerizable monomer represented by the following formula (b3) (hereinafter also referred to as "monomer (b3)"), and a polymerizable monomer represented by the following formula (b4) (hereinafter also referred to as "monomer (b4)"). The structural unit (B) has a structure in which the ethylenically unsaturated bond of the monomer (b) is cleaved to form a single bond.

[0030] CH ２ =CR ３ａ -CO-O-(C ｕ H ２ｕ -O) ｖ -C ｗ H ２ｗ -(SiR ３ｂ R ３ｃ -O) ｘ -SiR ３ｄ R ３ｅ R ３ｆ ... (b1) CH ２ =CR ４ａ -CO-O-(C ｕ’ H ２ｕ’ -O)ｖ’ -C ｗ’ H ２ｗ’ -Si(OSiR ４ｂ R ４ｃ R ４ｄ ) ３ ... (b2) CH ２ =CR ２ａ -CO-O-(C ｋ’ H ２ｋ’ -O) ｌ’ -C ｍ’ H ２ｍ’ -Si((OSiR ２ｂ R ２ｃ ) ｒ -OSiR ２ｄ R ２ｅ R ２ｆ ) ２ -OSi((OSiR ２ｇ R ２ｈ ) ｓ -OSiR ２ｉ R ２ｊ R ２ｋ ) ２ -C о’ H ２о’ -(O-C ｐ’ H ２ｐ’ ) ｑ’ -O-CO-CR ２ｌ =CH ２ ... (b3) CH ２ =CR １ａ -CO-O-(C ｋ H ２ｋ -O) ｌ -C ｍ H ２ｍ -(SiR １ｂ R １ｃ -O) ｎ -SiR １ｄ R １ｅ -C о H ２о -(O-C ｐ H ２ｐ ) ｑ -O-CO-CR １ｆ =CH ２ ...(b4)

[0031] Here, R ３ａ represents a hydrogen atom or a methyl group, u represents an integer of 2 to 5, v represents a number of 0 to 50, w represents an integer of 2 to 5, x represents a number of 3 to 80, and R ３ｂ~R ３ｆ each independently represents an alkyl group, an alkoxy group, a phenyl group, a substituted phenyl group, a phenoxy group, or a substituted phenoxy group; R ４ａ represents a hydrogen atom or a methyl group, u' represents an integer of 2 to 5, v' represents a number of 0 to 50, w' represents an integer of 2 to 5, and R ４ｂ ~R ４ｄ are each independently an alkyl group, —(OSiR ５１ R ５２ ) ｙ -OSiR ５３ R ５４ R ５５ (where y is an integer from 0 to 20, R ５１ ~R ５５ represents an alkyl group, or —R ５６ - (OC ２ H ４ ) ｙ’ -OR ５７ (where y' represents an integer of 1 to 20, and R ５６ represents an alkylene group, and R ５７ represents an alkyl group; ２ａ and R ２ｌ each independently represents a hydrogen atom or a methyl group; k' and p' each independently represents an integer of 2 to 5; l' and q' each independently represents a number of 0 to 50; m' and o' each independently represents an integer of 2 to 5; r and s each independently represents a number of 0 to 20; R ２ｂ ~R ２ｋ each independently represents an alkyl group, R １ａ and R １ｆ each independently represents a hydrogen atom or a methyl group; k and p each independently represents an integer of 2 to 5; l and q each independently represents a number of 0 to 50; m and o each independently represents an integer of 2 to 5; n represents a number of 3 to 80; R １ｂ ~R １ｅ each independently represents an alkyl group, an alkoxy group, a phenyl group, a substituted phenyl group, a phenoxy group or a substituted phenoxy group.

[0032] In formula (b1), u represents an integer of 2 to 5, with 2 or 3 being preferred from the standpoint of cost. It is also possible to use a combination of monomers (b1) where u is 2 and 3. v represents the average degree of polymerization of the polyether structure and represents a number from 0 to 50. If v is 50 or less, the water resistance of the coating film tends to be good. In particular, a v of 30 or less is preferred, as this results in excellent recoatability with the old coating film. v may be 0, but is preferably greater than 0, as this tends to result in good recoatability with the old coating film. v is preferably greater than 0 and not greater than 30, more preferably 3 to 25, and even more preferably 5 to 20. w represents an integer from 2 to 5, with 2 or 3 being preferred. x represents the average degree of polymerization of the polysiloxane structure and represents a number from 3 to 80. When x is equal to or greater than the lower limit, the resin composition or coating composition containing copolymer (X) tends to exhibit antifouling effect in the coating film even when the composition does not contain an antifouling agent, and when x is equal to or less than the upper limit, the monomer (b1) is compatible with the monomer (a) and the like, and the resulting copolymer (X) has good solubility in organic solvents. x is preferably 5 to 50, more preferably 8 to 40. ３ｂ ~R ３ｆ The number of carbon atoms in the alkyl group and the alkoxy group in R is preferably 1 to 18. Examples of the substituent in the substituted phenyl group and the substituted phenoxy group include an alkyl group and an alkoxy group. ３ｂ ~R ３ｆ are each preferably an alkyl group having 1 to 18 carbon atoms, more preferably a methyl group or an ethyl group, and particularly preferably a methyl group. ３ａ ~R ３ｆ , u, v, w and x are each independent, and when the same symbol exists within or between molecules, they may be different.

[0033] Specific examples of the monomer (b1) include those in which v is 0, such as FM-0711, FM-0721, and FM-0725 (all trade names) manufactured by JNC Corporation, and X-24-8201, X-22-174DX, and X-22-2426 (all trade names) manufactured by Shin-Etsu Chemical Co., Ltd. Examples of those in which v is greater than 0 include F2-254-04 and F2-254-14 (trade names) manufactured by Dow Corning Toray Co., Ltd. One type of monomer (b1) may be used alone, or multiple types may be used in combination.

[0034] In formula (b2), u' is an integer of 2 to 5, preferably 2 or 3 in terms of cost. As the monomer (b2), it is possible to use a combination of a monomer where u' is 2 and a monomer where u' is 3. v' is the average degree of polymerization of the polyether structure, and represents a number from 0 to 50. If v' is 50 or less, the water resistance of the coating film tends to be good. In particular, it is preferable that v' is 30 or less, as this will result in excellent recoatability with the old coating film. v' may be 0, but is preferably greater than 0, as this will tend to result in good recoatability with the old coating film. v' is preferably greater than 0 and not greater than 30, more preferably 3 to 25, and even more preferably 5 to 20. w' represents an integer from 2 to 5, preferably 2 or 3. R ４ｂ ~R ４ｄ The alkyl group in is preferably an alkyl group having 1 to 18 carbon atoms, and examples thereof include a methyl group, an ethyl group, an n-propyl group, and an n-butyl group. Among these, a methyl group or an ethyl group is preferred, and a methyl group is particularly preferred. y is the average degree of polymerization of the polysiloxane structure and represents an integer of 0 to 20. y' is the average degree of polymerization of the polyether structure and represents an integer of 1 to 20. When y and y' are not more than the upper limit values, the monomer (b2) is compatible with the monomer (a) and the like, and the resulting copolymer (X) has good solubility in organic solvents. y and y' are each preferably 10 or less, more preferably 5 or less. R ５１ ~R ５５ , R ５７ The alkyl group in R ４ｂ ~R ４ｄ The alkyl group may be the same as the alkyl group in R ５６In the formula, the number of carbon atoms of the alkylene group is preferably 1 to 18. ４ａ ~R ４ｄ , u', v', w', y and y' are each independent, and when the same symbol exists within or between molecules, they may be different.

[0035] Specific examples of the monomer (b2) include those in which v' is 0, such as TM-0701 (trade name) manufactured by JNC Corporation, X-22-2404 (trade name) manufactured by Shin-Etsu Chemical Co., Ltd., and F2-250-01 and F2-302-01 (all trade names) manufactured by Dow Corning Toray Co., Ltd. Examples of those in which v' is greater than 0 include F2-302-04 (trade name) manufactured by Dow Corning Toray Co., Ltd. One type of monomer (b2) may be used alone, or multiple types may be used in combination.

[0036] In formula (b3), k' and p' represent integers of 2 to 5, with 2 or 3 being preferred from the standpoint of cost. Monomer (b3) may also be used in combination with those in which k' and p' are 2 and 3. l' and q' represent the average degree of polymerization of the polyether structure and represent a number from 0 to 50. When l' and q' are 50 or less, the water resistance of the coating film tends to be good. Being 30 or less is particularly preferred, as this results in excellent recoatability with the old coating film. l' and q' may be 0, but are preferably greater than 0, as this tends to result in good recoatability with the old coating film. l' and q' are preferably greater than 0 but not greater than 30, more preferably 3 to 25, and even more preferably 5 to 20. m' and o' represent integers of 2 to 5, with 2 or 3 being preferred. r and s represent the average degree of polymerization of the polysiloxane structure and represent a number from 0 to 20. When r and s are equal to or less than the upper limit values, the monomer (b3) is compatible with the monomer (a) and the like, and the resulting copolymer (X) has good solubility in organic solvents. r and s are preferably equal to or less than 10, more preferably equal to or less than 5. ２ｂ ~R ２ｋ The alkyl group in R is preferably an alkyl group having 1 to 18 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, or an n-butyl group. Among these, a methyl group or an ethyl group is preferred, and a methyl group is particularly preferred. ２ａ ~R２ｌ , k', l', m', n', o', p', q', r and s are each independent, and when the same symbol exists within or between molecules, they may be different.

[0037] Specific examples of the monomer (b3) include F2-312-01 (trade name) manufactured by Dow Corning Toray Co., Ltd., for example, as a monomer in which l' and q' are 0. Examples of the monomer (b3) in which l' and q' are greater than 0 include F2-312-04 (trade name) manufactured by Dow Corning Toray Co., Ltd. One type of monomer (b3) may be used alone, or multiple types may be used in combination.

[0038] In formula (b4), k and p represent integers of 2 to 5, with 2 or 3 being preferred from the standpoint of cost. It is also possible to use a combination of monomers (b4) in which k and p are 2 and 3. l and q represent the average degree of polymerization of the polyether structure and represent a number from 0 to 50. If l and q are 50 or less, the water resistance of the coating film tends to be good. Being 30 or less is particularly preferred, as this results in excellent recoatability with the old coating film. l and q may be 0, but are preferably greater than 0, as this tends to result in good recoatability with the old coating film. l and q are preferably greater than 0 but not greater than 30, more preferably 3 to 25, and even more preferably 5 to 20. m and o represent integers from 2 to 5, with 2 or 3 being preferred. n represents the average degree of polymerization of the polysiloxane structure and represents a number from 3 to 80. When n is equal to or greater than the lower limit, the resin composition or coating composition containing copolymer (X) tends to exhibit antifouling effect in the coating film even when the composition does not contain an antifouling agent, and when n is equal to or less than the upper limit, the monomer (b4) is compatible with the monomer (a) and the like, and the resulting copolymer (X) has good solubility in organic solvents. n is preferably 5 to 50, more preferably 8 to 40. １ｂ ~R １ｅ The number of carbon atoms in the alkyl group and the alkoxy group in R is preferably 1 to 18. Examples of the substituent in the substituted phenyl group and the substituted phenoxy group include an alkyl group and an alkoxy group. １ｂ ~R １ｅare each preferably an alkyl group having 1 to 18 carbon atoms, more preferably a methyl group or an ethyl group, and particularly preferably a methyl group. １ａ ~R １ｆ , k, l, m, n, o, p, and q are each independent, and when the same symbol exists within or between molecules, they may be different.

[0039] Specific examples of the monomer (b4) include those in which l and q are 0, such as FM-7711, FM-7721, and FM-7725 (all trade names) manufactured by JNC Corporation, and F2-311-02 (trade name) manufactured by Dow Corning Toray Co., Ltd. Those in which l and q are greater than 0, such as F2-354-04 (trade name) manufactured by Dow Corning Toray Co., Ltd. One type of monomer (b4) may be used alone, or multiple types may be used in combination.

[0040] In terms of the crack resistance of the coating film and adhesion to the substrate, the structural unit (B) preferably consists solely of structural units based on monomer (b1) or (b2), which is the monomer (b) that contains an ethylenically unsaturated bond at one end.In terms of recoatability, the structural unit (B) preferably contains a structural unit based on monomer (b1) or (b2) and a structural unit based on monomer (b3) or (b4).

[0041] When the structural unit (B) contains a structural unit based on monomer (b1) or (b2) and a structural unit based on monomer (b3) or (b4), the molar ratio thereof (structural unit based on monomer (b3) or (b4) / structural unit based on monomer (b1) or (b2)) is preferably 1 / 99 to 80 / 20, more preferably 3 / 97 to 60 / 40. When the ratio is 80 / 20 or less, a coating film with excellent crack resistance and adhesion to the substrate tends to be obtained. When the ratio is 1 / 99 or more, the coating film formed from the resin composition or coating composition containing copolymer (X) tends to have better long-term antifouling properties and recoatability.

[0042] (Structural Unit (C)) The monomer (c) is a polymerizable monomer other than the monomer (a) and the monomer (b). The monomer (c) may be any monomer that is copolymerizable with the monomer (a) and the monomer (b), and examples thereof include compounds containing an ethylenically unsaturated bond (excluding the monomer (a) and the monomer (b)).

[0043] Examples of the monomer (c) include the following: substituted or unsubstituted alkyl (meth)acrylates [e.g., methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, i-propyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, behenyl (meth)acrylate, 1-methyl-2-methoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, 3-methyl-3-methoxybutyl (meth)acrylate], substituted or unsubstituted aralkyl (meth)acrylates [e.g., benzyl ( hydrophobic group-containing (meth)acrylic acid ester monomers such as phenyl(meth)acrylate, m-methoxyphenylethyl(meth)acrylate, p-methoxyphenylethyl(meth)acrylate, substituted or unsubstituted aryl(meth)acrylates [for example, phenyl(meth)acrylate, m-methoxyphenyl(meth)acrylate, p-methoxyphenyl(meth)acrylate, o-methoxyphenylethyl(meth)acrylate], alicyclic(meth)acrylates [for example, isobornyl(meth)acrylate, cyclohexyl(meth)acrylate], trifluoroethyl(meth)acrylate, perfluorooctyl(meth)acrylate, and perfluorocyclohexyl(meth)acrylate; Oxyethylene group-containing (meth)acrylic acid ester monomers such as 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-butoxyethyl (meth)acrylate, butoxydiethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, phenoxyethyl (meth)acrylate, and 2-(2-ethylhexaoxy)ethyl (meth)acrylate; hydroxyl group-containing (meth)acrylic acid ester monomers such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and glycerol (meth)acrylate;Terminally alkoxyallylated polyether monomers such as methoxy polyethylene glycol allyl ether, methoxy polypropylene glycol allyl ether, butoxy polyethylene glycol allyl ether, butoxy polypropylene glycol allyl ether, methoxy polyethylene glycol-polypropylene glycol allyl ether, and butoxy polyethylene glycol-polypropylene glycol allyl ether; epoxy group-containing vinyl monomers such as glycidyl (meth)acrylate, α-ethyl glycidyl acrylate, and 3,4-epoxybutyl (meth)acrylate; primary or secondary amino group-containing vinyl monomers such as butylaminoethyl (meth)acrylate and (meth)acrylamide; tertiary amino group-containing vinyl monomers such as dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate, dimethylaminobutyl (meth)acrylate, dibutylaminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylamide, and dimethylaminopropyl (meth)acrylamide; heterocyclic basic monomers such as vinylpyrrolidone, vinylpyridine, and vinylcarbazole;Trimethylsilyl (meth)acrylate, triethylsilyl (meth)acrylate, tri-n-propylsilyl (meth)acrylate, tri-n-butylsilyl (meth)acrylate, tri-n-amylsilyl (meth)acrylate, tri-n-hexylsilyl (meth)acrylate, tri-n-octylsilyl (meth)acrylate, tri-n-dodecylsilyl (meth)acrylate, triphenylsilyl (meth)acrylate, tri-p-methylphenylsilyl (meth)acrylate, tribenzylsilyl (meth)acrylate, triisopropylsilyl (meth)acrylate, triisobutylsilyl (meth)acrylate, tri-s-butylsilyl (meth)acrylate, tri-2-methylisopropylsilyl (meth)acrylate, tri-t-butylsilyl (meth)acrylate, ethyldimethylsilyl (meth)acrylate, n-butyldimethylsilyl (meth) Organosilyl group-containing vinyl monomers such as acrylate, diisopropyl-n-butylsilyl (meth)acrylate, n-octyldi-n-butylsilyl (meth)acrylate, diisopropylstearylsilyl (meth)acrylate, dicyclohexylphenylsilyl (meth)acrylate, t-butyldiphenylsilyl (meth)acrylate, lauryldiphenylsilyl (meth)acrylate, triisopropylsilylmethyl maleate, triisopropylsilylamyl maleate, tri-n-butylsilyl-n-butyl maleate, t-butyldiphenylsilyl methyl maleate, t-butyldiphenylsilyl-n-butyl maleate, triisopropylsilylmethyl fumarate, triisopropylsilylamyl fumarate, tri-n-butylsilyl-n-butyl fumarate, t-butyldiphenylsilyl methyl fumarate, and t-butyldiphenylsilyl-n-butyl fumarate; Acid anhydride group-containing vinyl monomers such as maleic anhydride and itaconic anhydride;Methacrylic acid, acrylic acid, crotonic acid, vinylbenzoic acid, fumaric acid, itaconic acid, maleic acid, citraconic acid, monomethyl maleate, monoethyl maleate, monobutyl maleate, monooctyl maleate, monomethyl itaconate, monoethyl itaconate, monobutyl itaconate, monooctyl itaconate, monomethyl fumarate, monoethyl fumarate, monobutyl fumarate, monooctyl fumarate, monoethyl citraconic acid, monohydroxyethyl tetrahydrophthalate (meth)acrylate, tetrahydrophthalic acid Carboxy group-containing ethylenically unsaturated monomers such as monohydroxypropyl phthalate (meth)acrylate, monohydroxybutyl tetrahydrophthalate (meth)acrylate, monohydroxyethyl phthalate (meth)acrylate, monohydroxypropyl phthalate (meth)acrylate, monohydroxyethyl succinate (meth)acrylate, monohydroxypropyl succinate (meth)acrylate, monohydroxyethyl maleate (meth)acrylate, and monohydroxypropyl maleate (meth)acrylate; unsaturated dicarboxylic acid diester monomers such as dimethyl maleate, dibutyl maleate, dimethyl fumarate, dibutyl fumarate, dibutyl itaconate, and diperfluorocyclohexyl fumarate; cyano group-containing vinyl monomers such as acrylonitrile and methacrylonitrile; vinyl ether monomers such as alkyl vinyl ethers [e.g., ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, 2-ethylhexyl vinyl ether, etc.] and cycloalkyl vinyl ethers [e.g., cyclohexyl vinyl ether, etc.]; vinyl ester monomers such as vinyl acetate, vinyl propionate, vinyl butyrate, and vinyl benzoate; aromatic vinyl monomers such as styrene, vinyl toluene, and α-methylstyrene; halogenated olefins such as vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, and chlorotrifluoroethylene;Polyfunctional monomers such as ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, allyl methacrylate, triallyl cyanurate, diallyl maleate, and polypropylene glycol diallyl ether; macromonomers, etc.;

[0044] Examples of the macromonomer include a compound having an ethylenically unsaturated bond-containing group and having two or more structural units derived from a monomer having an ethylenically unsaturated bond-containing group. The two or more structural units of the macromonomer may be the same or different. Examples of the ethylenically unsaturated bond-containing group include CH ２ =C(COOR)-CH ２ Examples of the substituent include an alkyl group (excluding the case where R is an alkyl group having a substituent), an aryl group, a -COOR group, a -(meth)acryloyl group, a 2-(hydroxymethyl)acryloyl group, a vinyl group, etc. Here, R represents a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted alicyclic group, an unsubstituted or substituted aryl group, or an unsubstituted or substituted heterocyclic group. Examples of the substituent include an alkyl group (excluding the case where R is an alkyl group having a substituent), an aryl group, -COOR group, etc. ６１ , a cyano group, —OR ６２ , -NR ６３ R ６４ , -CONR ６５ R ６６ , a halogen atom, an allyl group, an epoxy group, a siloxy group, and a group exhibiting hydrophilicity or ionicity. ６１ ~R ６６each independently represents a hydrogen atom, an alkyl group, an alicyclic group, or an aryl group. As the monomer having an ethylenically unsaturated bond-containing group, for example, the various monomers listed above as examples of monomer (c) can be used (excluding macromonomers). Specific examples of macromonomers include those disclosed in WO 2013 / 108880. One or more of these monomers (c) can be appropriately selected and used as needed.

[0045] The monomer (c) is preferably a monofunctional monomer having one ethylenically unsaturated bond, and particularly preferably the ethylenically unsaturated bond is derived from an acryloyl group, in order to easily achieve a low viscosity even when the copolymer (X) has a high solid content when dissolved in an organic solvent. That is, the monomer (c) is particularly preferably a monofunctional monomer having one acryloyl group.

[0046] The structural unit (C) preferably contains a structural unit based on a hydrophobic group-containing (meth)acrylic acid ester monomer, in that it can provide a coating film formed from a resin composition or coating composition containing copolymer (X) with a good balance of flexibility, crack resistance or peel resistance, and long-term self-polishing properties. As the hydrophobic group-containing (meth)acrylic acid ester monomer, alkyl (meth)acrylate is preferred.

[0047] In terms of the solubility and crack resistance of a coating film formed from a resin composition or coating composition containing copolymer (X), the structural unit (C) preferably contains a structural unit based on an oxyethylene group-containing (meth)acrylic acid ester monomer. As the oxyethylene group-containing (meth)acrylic acid ester monomer, a compound represented by the following formula (3-1) (hereinafter also referred to as "monomer (c1)") is preferred. Z １ - (CH ２ CH ２ O) ｔ R ２１ ...(3-1) (where Z １ represents an acryloyloxy group or a methacryloyloxy group, and R ２１represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group, and t represents an integer of 1 to 15.

[0048] In formula (3-1), Z １ When the copolymer (X) is an acryloyloxy group, the hydrolysis rate of the monomer (c1) tends to be faster than when the copolymer (X) is an acryloyloxy group. １ can be selected arbitrarily. ２１ In the formula (I), examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, a hexyl group, and a 2-ethylhexyl group. The number of carbon atoms in the alkyl group is preferably 1 to 4, more preferably 1 to 3, and even more preferably 1 or 2. The aryl group is preferably an aryl group having 6 to 20 carbon atoms, and examples include a phenyl group and a naphthyl group. From the viewpoints of water resistance and crack resistance, t is preferably an integer of 1 to 10, more preferably an integer of 1 to 5, even more preferably an integer of 1 to 3, and particularly preferably 1 or 2.

[0049] (Content of each structural unit) The content of the structural unit (A) is 5 to 35% by mass, preferably 10 to 30% by mass, and more preferably 15 to 25% by mass, relative to the total mass (100% by mass) of all structural units constituting the copolymer (X). When the content of the structural unit (A) is equal to or greater than the lower limit, the coating film formed by the resin composition or paint composition containing the copolymer (X) has better self-polishing properties. When the content of the structural unit (A) is equal to or less than the upper limit, the coating film formed by the resin composition or paint composition containing the copolymer (X) has excellent crack resistance, maintains self-polishing properties over a long period of time, and has better antifouling effects.

[0050] The content of the structural unit (B) is 35 to 75% by mass, preferably 35 to 70% by mass, and more preferably 35 to 65% by mass, based on the total mass of all structural units constituting the copolymer (X). When the content of the structural unit (B) is equal to or greater than the lower limit, the coating film formed by the resin composition or coating composition containing the copolymer (X) exhibits excellent antifouling properties, even when an antifouling agent is not used in the resin composition or coating composition. When the content of the structural unit (B) is equal to or less than the upper limit, the coating film formed by the resin composition or coating composition containing the copolymer (X) exhibits excellent crack resistance, maintains self-polishing properties over a long period of time, and exhibits even more excellent antifouling properties.

[0051] The total content of the structural units (B) derived from monomer (b3) and the structural units (b4) is preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less, relative to the total mass of all structural units constituting copolymer (X). If the total content of the structural units derived from monomer (b3) and the structural units derived from monomer (b4) is below the upper limit, copolymer (X) tends to be obtained without gelation due to crosslinking during production. Furthermore, the viscosity of the solution of copolymer (X) tends to be low.

[0052] The total content of the structural units (A) and (B) is preferably 40 to 90% by mass, more preferably 45 to 85% by mass, and even more preferably 50 to 80% by mass, relative to the total mass of all structural units constituting the copolymer (X). The content of the structural unit (C) is preferably 10 to 60% by mass, more preferably 15 to 55% by mass, and even more preferably 20 to 50% by mass, relative to the total mass of all structural units constituting the copolymer (X).

[0053] When the structural unit (C) contains a structural unit based on an oxyethylene group-containing (meth)acrylic acid ester monomer, the content of this structural unit is preferably 1 to 60 mass%, more preferably 5 to 55 mass%, and even more preferably 10 to 50 mass%, relative to the total mass of all structural units constituting the copolymer (X). When the content of this structural unit is equal to or greater than the lower limit, the coating film formed from a resin composition or paint composition containing the copolymer (X) has higher hydrophilicity and better self-polishing properties. When the content of this structural unit is equal to or less than the upper limit, the coating film formed from a resin composition or paint composition containing the copolymer (X) has appropriate hydrolysis properties, maintains self-polishing properties over a long period of time, and has better antifouling properties.

[0054] When the structural unit (C) includes a structural unit based on a monomer (c) other than an oxyethylene group-containing (meth)acrylic acid ester monomer, such as a hydrophobic group-containing (meth)acrylic acid ester monomer, the content of this structural unit is preferably 1 to 60 mass%, more preferably 5 to 55 mass%, based on the total mass of all structural units constituting the copolymer (X). When the content of this structural unit is within the above range, the flexibility, crack resistance, and peel resistance of the coating film formed from the resin composition or paint composition containing the copolymer (X) are improved, and the antifouling effect is more excellent. Furthermore, when the content of this structural unit is equal to or less than the above upper limit, the coating film formed from the resin composition or paint composition containing the copolymer (X) has appropriate hydrolysis properties, maintains self-polishing properties over a long period of time, and has more excellent antifouling effect.

[0055] When the structural unit (C) contains a structural unit based on a (meth)acrylic macromonomer, the content of this structural unit is less than 13% by mass, preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 4% by mass or less, relative to the total mass of all structural units constituting the copolymer (X). Furthermore, it is more preferable that the copolymer (X) does not contain a structural unit based on a monomer (c) selected from macromonomers. When the content of the structural unit based on a (meth)acrylic macromonomer is equal to or less than the upper limit, the transparency of the coating film formed from the resin composition or coating composition containing the copolymer (X) is good.

[0056] The total of the structural units (A), (B), and (C) is 100% by mass. The content (% by mass) of each structural unit in the copolymer can be measured by known methods such as gas chromatography, high-performance liquid chromatography, and nuclear magnetic resonance spectroscopy.

[0057] At least a portion of the structural units constituting copolymer (X) are structural units based on a (meth)acrylic monomer. The content of the structural units based on a (meth)acrylic monomer is preferably 20 to 100% by mass, more preferably 40 to 100% by mass, relative to the total mass of all structural units constituting copolymer (X). The monomers (b1) to (b4) described above are all (meth)acrylic monomers, and structural unit (B) is a structural unit based on a (meth)acrylic monomer. The monomers (a1) and (a2) described above are all (meth)acrylic monomers, and when structural unit (A) is a structural unit based on monomer (a1) or (a2), structural unit (A) is also a structural unit based on a (meth)acrylic monomer. When copolymer (X) contains structural unit (C), structural unit (C) may or may not contain a structural unit based on a (meth)acrylic monomer.

[0058] Copolymer (X) is preferably a copolymer obtained by polymerizing a monomer mixture containing monomer (a) and monomer (b). Such a copolymer tends to have better water resistance than a copolymer obtained by converting copolymer (X0) having a carboxy group, which is obtained by polymerizing a monomer mixture containing monomer (a0) having an ethylenically unsaturated bond and a carboxy group and monomer (b), to structure (I). Typically, the content of monomer (a) is 5 to 35% by mass, and the content of monomer (b) is 35 to 75% by mass, based on 100% by mass of the monomer mixture. The monomer mixture preferably contains 5 to 35% by mass of monomer (a), 35 to 75% by mass of monomer (b), and 10 to 60% by mass of monomer (c), relative to 100% by mass of the total mass of the monomer mixture, and more preferably contains 10 to 30% by mass of monomer (a), 35 to 70% by mass of monomer (b), and 10 to 55% by mass of monomer (c). Furthermore, when monomer (c) contains a (meth)acrylic macromonomer, the content of the (meth)acrylic macromonomer is typically less than 13% by mass, relative to 100% by mass of the total mass of the monomer mixture, and is preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 4% by mass or less.

[0059] The content of each monomer is a ratio relative to the total amount of the monomer mixture. A more preferred range of the content of each monomer is the same as the preferred range of the content of the structural unit based on that monomer. That is, the structural units constituting copolymer (X) typically have a content of structural unit (A) of 5 to 35 mass% and a content of structural unit (B) of 35 to 75 mass% relative to the total mass of all structural units constituting copolymer (X), 100 mass%. The structural units constituting copolymer (X) preferably consist of 5 to 35 mass% of structural unit (A), 35 to 75 mass% of structural unit (B), and 10 to 60 mass% of structural unit (C), relative to the total mass of all structural units constituting copolymer (X), 100 mass%. More preferably, the structural units constituting copolymer (X) consist of 10 to 30 mass% of structural unit (A), 35 to 70 mass% of structural unit (B), and 10 to 55 mass% of structural unit (C).

[0060] The weight-average molecular weight of copolymer (X) is 2000 to 6500, preferably 2000 to 5000, more preferably 2500 to 4500, and even more preferably 3000 to 4000. When the weight-average molecular weight of copolymer (X) is equal to or less than the upper limit, the storage stability of a resin composition containing copolymer (X) and an organic solvent is excellent and the viscosity is less likely to increase over time during storage. Therefore, a coating composition with a high solids content (low VOC) and low viscosity can be easily obtained. When the weight-average molecular weight is equal to or greater than the lower limit, the durability of the coating film formed from the resin composition or coating composition containing copolymer (X) is excellent and the long-term antifouling properties are excellent.

[0061] The number average molecular weight (Mn) of the copolymer (X) is preferably 1000 to 2500, more preferably 1500 to 2000. The polydispersity (Mw / Mn) of the copolymer (X) is preferably 1.5 to 5.0, more preferably 2.2 to 3.0. The weight average molecular weight and number average molecular weight of the copolymer (X) are each measured by gel permeation chromatography (GPC) using polystyrene as a standard resin.

[0062] (Method for Producing Copolymer (X)) Examples of methods for producing copolymer (X) include the following production methods (α) and (β). Production method (α): A method of polymerizing a monomer mixture containing monomer (a) and monomer (b). Production method (β): A method of polymerizing a monomer mixture containing monomer (a0) having an ethylenically unsaturated bond and a carboxy group and monomer (b) to obtain copolymer (X0) having a carboxy group, and converting the carboxy group of this copolymer (X0) to structure (I).

[0063] "Production method (α)": In production method (α), a monomer mixture containing monomer (a) and monomer (b) (hereinafter also referred to as "monomer mixture (α1)") is polymerized. The monomer mixture (α1) may further contain monomer (c).

[0064] The composition of the monomer mixture (α1), i.e., the type of monomer constituting the monomer mixture (α1) and the content (% by mass) of each monomer relative to the total mass of all monomers, is the same as the composition of the copolymer (X), i.e., the type of monomer forming each structural unit constituting the copolymer (X) and the content (% by mass) of each structural unit relative to the total mass of all structural units.

[0065] As a method for polymerizing the monomer mixture (α1), for example, known polymerization methods such as solution polymerization, suspension polymerization, bulk polymerization, and emulsion polymerization can be applied. In terms of productivity and coating film performance, solution polymerization is preferred. The polymerization may be carried out by a known method using a known polymerization initiator. For example, a method may be used in which the monomer mixture (α1) is reacted in the presence of a radical initiator at a reaction temperature of 60 to 120°C for 4 to 14 hours. During the polymerization, a chain transfer agent may be used as necessary.

[0066] Known radical initiators can be used, and examples thereof include 2,2-azobisisobutyronitrile, 2,2-azobis(2,4-dimethylvaleronitrile), 2,2-azobis(2-methylbutyronitrile), benzoyl peroxide, cumene hydroperoxide, lauryl peroxide, di-t-butyl peroxide, and t-butylperoxy-2-ethylhexanoate. The content of the polymerization initiator is not particularly limited and can be set appropriately. Typically, the content of the polymerization initiator is about 0.1 to 20 parts by mass per 100 parts by mass of the polymerizable monomer.

[0067] Known chain transfer agents can be used, and examples thereof include mercaptans such as n-dodecyl mercaptan, thioglycolic acid esters such as octyl thioglycolate, α-methylstyrene dimer, terpinolene, etc. The content of the chain transfer agent is not particularly limited and can be set appropriately. Typically, the content of the chain transfer agent is about 0.0001 to 10 parts by mass per 100 parts by mass of the polymerizable monomer.

[0068] As the solvent used in the solution polymerization, for example, a general organic solvent such as toluene, xylene, methyl isobutyl ketone, or n-butyl acetate can be used.

[0069] "Production Method (β)": In Production Method (β), a monomer mixture containing monomer (a0) and monomer (b) (hereinafter also referred to as "monomer mixture (β1)") is polymerized to obtain a copolymer (X0) having a carboxy group, and the carboxy group of this copolymer (X0) is converted to Structure (I). The monomer mixture (β1) may further contain a monomer (c).

[0070] The composition of the monomer mixture (β1) is the same as that of the monomer mixture (α1), except that the monomer (a) is the monomer (a0). Examples of the monomer (m0) include (meth)acrylic acid, crotonic acid, isocrotonic acid, maleic acid, fumaric acid, itaconic acid, monomethyl maleate, and monomethyl fumarate. The polymerization of the monomer mixture (β1) can be carried out in the same manner as the polymerization of the monomer mixture (α1) in the production method (α).

[0071] As a method for converting the carboxy group of the copolymer (X0) into the structure represented by formula (1), for example, a method of reacting the copolymer (X0) with a metal oxide such as zinc oxide can be mentioned. As a method for converting the carboxy group of the copolymer (X0) into the structure represented by formula (2), for example, a method of reacting the copolymer (X0) with a metal oxide such as zinc oxide can be mentioned. ３２ and a metal oxide such as zinc oxide. The metal of the metal oxide corresponds to the above-mentioned M. The reaction between copolymer (X0) and a metal oxide, or the reaction between copolymer (X0), an organic acid, and a metal oxide can be carried out, for example, by raising the temperature to the reflux temperature, removing the distilled mixture of organic acid, water, and organic solvent, and continuing the reaction for 10 to 20 hours while replenishing the same amount of organic solvent.

[0072] <Organic Solvent> When the resin composition (1) contains an organic solvent, the coating suitability of the coating composition containing the resin composition (1) and the water resistance and film-forming properties of the coating film formed are improved. The organic solvent is not particularly limited, and a general organic solvent can be used, for example, hydrocarbon solvents such as toluene and xylene; ether solvents such as propylene glycol monomethyl ether-2-acetate; ketone solvents such as methyl isobutyl ketone; ester solvents such as n-butyl acetate; etc. These can be used alone or in combination of two or more.

[0073] <Other Components> As the other components, for example, other components listed in the coating composition described below can be used. However, the other components are not limited thereto, and can be appropriately selected from various known additives depending on the application of the resin composition (1). An example of the application of the resin composition (1) is a coating composition.

[0074] The content of copolymer (X) in resin composition (1) is preferably 45% by mass or more, more preferably 50% by mass or more, even more preferably 55% by mass or more, particularly preferably 60% by mass or more, and most preferably 64% by mass or more, relative to the total mass of resin composition (1). If the content of copolymer (X) is equal to or greater than the above-mentioned lower limit, a coating composition with a low VOC content can be easily obtained. The content of copolymer (X) is preferably an amount such that the viscosity of resin composition (1) measured at 25°C using a Gardner bubble viscometer is equal to or less than the preferred upper limit described below. Although this content varies depending on the weight-average molecular weight, glass transition temperature, and presence or absence of a crosslinked structure of copolymer (X), it is preferably 80% by mass or less, more preferably 85% by mass or less.

[0075] The content of the organic solvent in the resin composition (1) is 50% by mass or less, preferably 45% by mass or less, and more preferably 40% by mass or less, relative to the total mass of the resin composition (1). If the content of the organic solvent is equal to or less than the upper limit, a coating composition with a low VOC content can be easily obtained. The content of the organic solvent is preferably an amount such that the viscosity of the resin composition (1) measured at 25°C using a Gardner bubble viscometer is equal to or less than the preferred upper limit described below. The content of the organic solvent varies depending on the weight average molecular weight, glass transition temperature, presence or absence of a crosslinked structure, etc. of the copolymer (X), but is preferably 15% by mass or more, more preferably 20% by mass or more, relative to the total mass of the resin composition (1).

[0076] The solid content (heat residue) of the resin composition (1) is preferably 50% by mass or more, more preferably 55% by mass or more, and even more preferably 60% by mass or more, relative to the total mass of the resin composition (1). If the solid content is equal to or greater than the lower limit, a coating composition with a low VOC content can be easily obtained. From the viewpoint of the viscosity of the resin composition (1), the solid content of the resin composition (1) is preferably 85% by mass or less, more preferably 80% by mass or less, relative to the total mass of the resin composition (1). The solid content is measured by the method described in the Examples below.

[0077] When the solid content concentration of the resin composition (1) is 50% by mass, the viscosity of the resin composition (1) measured with a Gardner bubble viscometer at 25°C (hereinafter also referred to as "Gardner viscosity") is Z or less, preferably W or less, more preferably V or less, and even more preferably T or less. When the solid content concentration of the resin composition (1) is 50% by mass, the viscosity of the resin composition (1) measured with a Brookfield viscometer at 25°C (hereinafter also referred to as "B-type viscosity") is preferably less than 5000 mPa·s, more preferably less than 3000 mPa·s, even more preferably less than 2000 mPa·s, and particularly preferably less than 1000 mPa·s. If the viscosity (B-type viscosity or Gardner viscosity) of the resin composition (1) is equal to or less than the upper limit, the resin composition (1) can be blended with an antifouling agent or painted without further adding an organic solvent for dilution, and a coating composition with a low VOC content can be obtained. The viscosity of the resin composition (1) at a solid content of at least 50% by mass is preferably not more than the above-mentioned preferred upper limit. The lower limit of the viscosity of the resin composition (1) is not particularly limited. In terms of suppressing paint sagging during application, the Gardner viscosity at 25 ° C is preferably B or higher, and the B-type viscosity at 25 ° C is preferably 100 mPa·s or higher. Therefore, when the solid content concentration of the resin composition (1) is 50% by mass, the Gardner viscosity of the resin composition (1) at 25 ° C is preferably B or higher and Z or lower. The B-type viscosity of the resin composition (1) at 25 ° C is preferably 100 mPa·s or higher and lower than 5000 mPa·s, more preferably 100 mPa·s or higher and lower than 3000 mPa·s, even more preferably 100 mPa·s or higher and lower than 2000 mPa·s, and particularly preferably 100 mPa·s or higher and lower than 1,000 mPa·s.

[0078] The viscosity of the resin composition (1) can be adjusted by the solid content (content of copolymer (X) and other components) of the resin composition (1), the weight average molecular weight of copolymer (X), the glass transition temperature, the presence or absence of a crosslinked structure, etc. For example, the viscosity tends to be lower as the solid content, particularly the content of copolymer (X), is lower. Furthermore, the viscosity tends to be lower as the weight average molecular weight of copolymer (X) is smaller or the glass transition temperature is lower.

[0079] The resin composition (1) can be prepared, for example, by producing the copolymer (X) as described above, and then adding and mixing an organic solvent and other components as necessary. When the copolymer (X) is produced by solution polymerization, it is not necessary to add an organic solvent. The VOC content of the resin composition (1) is preferably 500 g / L or less, more preferably 480 g / L or less, and even more preferably 440 g / L or less. If the VOC content is equal to or less than the upper limit, the amount of volatilized organic solvent can be sufficiently suppressed. In terms of viscosity and paintability, the VOC content of the resin composition (1) is preferably 350 g / L or more. The VOC content can be adjusted by the content of the organic solvent.

[0080] Here, the VOC content of a resin composition is the mass of VOCs per 1 L of resin composition, and is calculated from the following formula using the specific gravity and solid content (heating residue) values ​​of the resin composition: VOC content (g / L) = specific gravity of paint composition × 1000 × (100 - solid content (mass%)) / 100 The specific gravity is calculated by filling a 100 mL specific gravity cup with the resin composition at 25°C and measuring the mass. The solid content (heating residue) is measured by the method described in the examples below.

[0081] <Action and Effect> In the resin composition (1) described above, the copolymer (X) has a specific composition (the content of the structural unit (A) is 5 to 35% by mass, the content of the structural unit (B) is 35 to 75% by mass, and the content of the structural unit based on a (meth)acrylic macromonomer is less than 13% by mass) and a weight-average molecular weight of 2,000 or more and 6,500 or less. This makes it possible to form a coating film that exhibits excellent transparency and antifouling effect, and also makes it resistant to thickening during storage and has excellent storage stability.

[0082] Copolymer (X) contains structural unit (A), resulting in structure (I) in which the carboxyl group is protected by a specific group. Therefore, it is hydrolyzable in seawater, etc. Therefore, coating films containing copolymer (X) exhibit self-polishing properties in seawater, etc. That is, copolymer (X) has structure (I), and in this state, it is insoluble in seawater. However, upon contact with seawater, structure (I) is hydrolyzed, generating carboxyl groups and the like, causing it to dissolve in seawater. The coating film surface gradually dissolves in seawater, resulting in surface renewal (self-polishing). Furthermore, copolymer (X) contains structural unit (B), resulting in polysiloxane blocks. Therefore, coating films containing copolymer (X) are less susceptible to adhesion of marine organisms and other fouling, and exhibit excellent antifouling effects even when the coating film does not contain an antifouling agent. When an antifouling agent is contained, the coating film undergoes surface renewal, resulting in the antifouling agent being constantly exposed on the coating film surface, allowing the antifouling effect of the antifouling agent to be stably exerted over a long period of time. Furthermore, copolymer (X) has a combination of a specific amount of structural unit (A) containing a hydrophilic structure (I) as a hydrolyzable structure and a specific amount of structural unit (B) containing a hydrophobic polysiloxane block, resulting in a more excellent long-term antifouling effect. This is thought to be because the inclusion of a specific amount of hydrophilic structure (I) and a specific amount of hydrophobic polysiloxane block causes the coating film to become a phase-separated film, which suppresses excessive dissolution and swelling of the coating film due to repeated hydrolysis of only the surface layer of the coating film, thereby allowing the excellent antifouling effect to be stably exerted over a long period of time.

[0083] Conventionally, resin compositions containing a copolymer containing a specific amount of hydrophilic structure (I) and a specific amount of hydrophobic polysiloxane blocks, as described above, and an organic solvent have tended to increase in viscosity over time and exhibit poor storage stability due to the copolymer's hydrophilic and hydrophobic properties. When the resin composition thickens, the organic solvent content must be increased to achieve a viscosity suitable for coatings, resulting in a high VOC content. Resin composition (1) exhibits good storage stability when the weight-average molecular weight of copolymer (X) is within a specific low molecular weight range. Therefore, resin composition (1) can be made into a high-solids, low-viscosity solution, and by using resin composition (1), a coating composition with a low VOC content can be obtained. When copolymer (X) has a composition within the above range and a weight-average molecular weight exceeding 6,500, the composition tends to thicken over time. This is thought to be because the cohesive force of the polymer increases, and by combining the hydrophilic properties of the structural unit (A) and the hydrophobic properties of the structural unit (B), the size of the polymer chain gradually changes over time in the organic solvent, reducing the solubility in the organic solvent and causing the viscosity to increase. When the viscosity of the thickened resin composition is remeasured after heating at a high temperature such as the polymerization temperature of copolymer (X), the viscosity returns to the viscosity immediately after production, and no change in molecular weight is observed, so it is presumed that it takes time for copolymer (X) to reach an optimal polymer chain size in the organic solvent.

[0084] Because of the above effects, the resin composition (1) is suitable for use as a coating composition, particularly as an antifouling coating composition. The resin composition (1) can be used as is, or mixed with an antifouling agent, etc., as necessary, to form a coating composition. However, the use of the resin composition (1) is not limited thereto, and it can also be used for purposes other than coating compositions.

[0085] [Resin composition (2)] A resin composition according to another embodiment of the present invention (hereinafter also referred to as "resin composition (2)") contains a copolymer (X) and an organic solvent. The copolymer (X) and the organic solvent are the same as those described above. The copolymer (X) contained in the resin composition (2) may be one type or two or more types. The same applies to the organic solvent. The resin composition (2) may further contain other components other than the copolymer (X) and the organic solvent, as necessary. As the other components, for example, the other components listed in the coating composition described below can be used.

[0086] The content of copolymer (X) in resin composition (2) is preferably 10 to 65 mass%, more preferably 15 to 60 mass%, and even more preferably 20 to 55 mass%, relative to the total mass of resin composition (2). When the content of copolymer (X) is equal to or greater than the lower limit, the coating film obtained from resin composition (2) has better antifouling properties. When the content of copolymer (X) is equal to or less than the upper limit, the coatability of resin composition (2) is better.

[0087] The content of the organic solvent in the resin composition (2) may be an amount that results in a VOC content of 500 g / L or less, and is preferably 10 to 50 mass %, more preferably 15 to 50 mass %, and even more preferably 20 to 45 mass %, relative to the total mass of the resin composition (2). When the content of the organic solvent is equal to or less than the upper limit, the VOC content is sufficiently low. When the content of the organic solvent is equal to or more than the lower limit, the viscosity of the resin composition (2) is easily reduced.

[0088] The solid content (heating residue) of the resin composition (2) may be any amount so long as the VOC content is 500 g / L or less, and is preferably 50 to 85 mass %, more preferably 55 to 80 mass %, and even more preferably 55 to 75 mass %, relative to the total mass of the resin composition (2). If the solid content is equal to or greater than the lower limit, the VOC content is sufficiently low. If the solid content is equal to or less than the upper limit, the viscosity of the resin composition (2) can be easily reduced.

[0089] The VOC content of the resin composition (2) is 500 g / L or less, preferably 480 g / L or less, and more preferably 440 g / L or less. If the VOC content is equal to or less than the upper limit, the amount of volatilized organic solvent can be sufficiently suppressed. In terms of viscosity and paintability, the VOC content of the resin composition (2) is preferably 350 g / L or more. The VOC content can be adjusted by the content of the organic solvent.

[0090] When the solid content concentration of the resin composition (2) is 50% by mass, the Gardner viscosity of the resin composition (2) is preferably Z or less, more preferably W or less, even more preferably V or less, and particularly preferably T or less. The B-type viscosity of the resin composition (2) at 25°C is preferably less than 5000 mPa·s, more preferably less than 3000 mPa·s, and even more preferably less than 1000 mPa·s. If the viscosity (B-type viscosity or Gardner viscosity) of the resin composition (2) is below the above upper limit, the resin composition (2) can be blended with an antifouling agent or painted without further adding an organic solvent for dilution, and a paint composition with a low VOC content can be obtained. Furthermore, if the viscosity of the resin composition (2) is below the above upper limit, it is easy to paint. It is preferable that the viscosity of the resin composition (2) at a solid content of at least 50% by mass is below the above preferred upper limit.

[0091] The lower limit of the B-type viscosity of the resin composition (2) at 25°C is not particularly limited, but in terms of the coating film properties, the Gardner viscosity at 25°C is preferably B or higher, and more preferably 100 mPa·s or higher. Therefore, when the solid content concentration of the resin composition (2) is 50 mass%, the Gardner viscosity of the resin composition (2) at 25°C is more preferably B or higher and Z or lower. The B-type viscosity of the resin composition (2) at 25°C is preferably 100 mPa·s or higher and lower than 5000 mPa·s, more preferably 100 mPa·s or higher and lower than 3000 mPa·s, even more preferably 100 mPa·s or higher and lower than 2000 mPa·s, and particularly preferably 100 mPa·s or higher and lower than 1,000 mPa·s.

[0092] The resin composition (2) can be prepared, for example, by producing the copolymer (X) as described above, and then adding an organic solvent and other components as necessary, followed by mixing. When the copolymer (X) is produced by a solution polymerization method, it is not necessary to add an organic solvent. The resin composition (2) can be prepared, for example, in the same manner as the resin composition (1), by producing the copolymer (X), and then adding an organic solvent and other components as necessary, followed by mixing.

[0093] <Action and Effect> In the resin composition (2) described above, the copolymer (X) has a specific composition (the content of the structural unit (A) is 5 to 35% by mass, the content of the structural unit (B) is 35 to 75% by mass, and the content of the structural unit based on a (meth)acrylic macromonomer is less than 13% by mass) and a weight-average molecular weight of 2,000 or more and 6,500 or less. This makes it possible to form a coating film that exhibits excellent transparency and antifouling effect, and also makes it resistant to thickening during storage and has excellent storage stability. Furthermore, in resin composition (2), polymer (X) has a specific composition (the content of structural unit (A) is 5 to 35% by mass, the content of structural unit (B) is 35 to 75% by mass, and the content of structural units based on (meth)acrylic macromonomers is less than 13% by mass) and a weight-average molecular weight of 2,000 or more and 6,500 or less, and the Gardner viscosity of resin composition (2) when the solids concentration is 50% by mass is Z or less, so that the transparency and antifouling effect of the coating film are superior, and the storage stability is also superior.

[0094] Because of the above effects, the resin composition (2) is suitable for use as a coating composition, particularly as an antifouling coating composition. The resin composition (2) of this embodiment can be used as is, or mixed with an antifouling agent, etc., as necessary, to form a coating composition. However, the use of the resin composition (2) is not limited thereto, and it can also be used for purposes other than coating compositions.

[0095] [Coating composition] A coating composition according to one embodiment of the present invention contains the resin composition (1) or (2) described above, and also contains a copolymer (X) and an organic solvent. The copolymer (X) and the organic solvent are the same as those described above. The coating composition may contain one or more types of copolymer (X). The same applies to the organic solvent. The coating composition may further contain other components in addition to the copolymer (X) and the organic solvent, as necessary. At least a portion of the components contained in the coating composition are derived from the resin composition (1) or (2). A portion of the components contained in the coating composition may not be derived from the resin composition (1) or (2) described above (compounded during the production of the coating composition).

[0096] <Other Components> The coating composition may further contain a silicone oil. When the coating composition contains a silicone oil, the coating film formed by the coating composition has better antifouling properties. Examples of silicone oils include straight silicone oils such as dimethylsilicone oil, methylphenylsilicone oil, and methylhydrogensilicone oil, as well as modified silicone oils. Modified silicone oils are silicone oils in which organic groups other than methyl and phenyl groups (hereinafter also referred to as "modified groups") have been introduced into some of the silicon atoms of straight silicone oils. Examples of modifying groups include chlorophenyl groups, methylstyrene groups, long-chain alkyl groups (e.g., alkyl groups having 2 to 18 carbon atoms), polyether groups, carbinol groups, aminoalkyl groups, epoxy groups, and (meth)acryloyl groups. These silicone oils can be used alone or in combination of two or more. Among the above silicone oils, polyether-modified silicone oils, which have polyether groups as modifying groups, are preferred from the perspective of antifouling properties.

[0097] As the silicone oil, commercially available products can be used. Examples of commercially available silicone oils include "KF-96", "KF-50", "KF-54", "KF-56", and "KF-6016" (all manufactured by Shin-Etsu Chemical Co., Ltd.), "TSF451" (manufactured by Momentive Performance Materials), "Fluid47" (manufactured by Rhoneplan (France)), "SH200", "SH510", "SH550", "SH710", "DC200", "ST-114PA", and "FZ209" (all manufactured by Dow Corning Toray Co., Ltd.).

[0098] The coating composition may further contain an antifouling agent from the viewpoint of the antifouling properties of the coating film. When the coating composition contains an antifouling agent, the antifouling properties of the coating film formed by the coating composition are even better. Examples of antifouling agents include inorganic antifouling agents and organic antifouling agents, and one or more types can be appropriately selected and used depending on the required performance. Specific examples of antifouling agents include copper-based antifouling agents such as cuprous oxide, copper thiocyanate, and copper powder, compounds of other metals (lead, zinc, nickel, etc.), amine derivatives such as diphenylamine, nitrile compounds, benzothiazole-based compounds, maleimide-based compounds, and pyridine-based compounds. These can be used alone or in combination of two or more types.

[0099] More specifically, antifouling agents include 4-bromo-2-(4-chlorophenyl)-5-(trifluoromethyl)-1H-pyrrole-3-carbonitrile, manganese ethylenebisdithiocarbamate, zinc dimethyldithiocarbamate, 2-methylthio-4-t-butylamino-6-cyclopropylamino-s-triazine, 2,4,5,6-tetrachloroisophthalonitrile, N,N-dimethyldichlorophenylurea, zinc ethylenebisdithiocarbamate, copper rhodanide, 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one, N-(fluorodichloromethylthio)phthalimide, N,N'-dimethyl-N'-phenyl-(N-fluorodichloromethylthio) Examples of suitable amines include sulfamide, 2-pyridinethiol-1-oxide zinc salt (also known as "zinc pyrithione"), tetramethylthiuram disulfide, Cu-10% Ni solid solution alloy, 2,4,6-trichlorophenylmaleimide 2,3,5,6-tetrachloro-4-(methylsulfonyl)pyridine, 3-iodo-2-propynyl butylcarbamate, diiodomethyl paratolyl sulfone, bisdimethyldithiocarbamoylzinc ethylene bisdithiocarbamate, phenyl(bispyridyl)bismuth dichloride, 2-(4-thiazolyl)-benzimidazole, medetomidine, pyridinetriphenylborane, and 4,5-dichloro-2-n-octyl-isothiazolin-3-one.

[0100] Among the above, the antifouling agent preferably contains at least one selected from the group consisting of cuprous oxide, 4-bromo-2-(4-chlorophenyl)-5-(trifluoromethyl)-1H-pyrrole-3-carbonitrile (hereinafter also referred to as "antifouling agent (d1)"), medetomidine, and 4,5-dichloro-2-n-octyl-isothiazolin-3-one, from the viewpoint of antifouling properties. When cuprous oxide and the antifouling agent (d1) are combined, the ratio (mass ratio) thereof, cuprous oxide / antifouling agent (d1), is preferably 80 / 20 to 99 / 1, and more preferably 90 / 10 to 99 / 1. At least one selected from the group consisting of cuprous oxide, antifouling agent (d1), medetomidine, and 4,5-dichloro-2-n-octyl-isothiazolin-3-one may be combined with other antifouling agents.

[0101] The coating composition may contain a silicon compound such as dimethylpolysiloxane (excluding silicone oil) or a fluorine-containing compound such as a fluorinated hydrocarbon, for the purpose of imparting lubricity to the coating surface and preventing the adhesion of organisms.

[0102] The coating composition may contain various pigments, antifoaming agents, leveling agents, pigment dispersants (e.g., anti-settling agents), anti-sagging agents, matting agents, ultraviolet absorbers, antioxidants, heat resistance improvers, slip agents, preservatives, plasticizers, viscosity control agents, etc.

[0103] The inclusion of a plasticizer in the coating composition can improve the crack resistance and peel resistance of the coating film. As the plasticizer, chlorinated paraffin is preferred because it can improve the crack resistance and peel resistance of the coating film. Organic waxes such as semi-synthetic waxes and synthetic waxes are preferred because they function as anti-settling and anti-sagging agents and can improve the storage stability and pigment dispersibility of the coating composition, and polyethylene wax, oxidized polyethylene wax, and polyamide wax are more preferred.

[0104] Examples of pigments include zinc oxide, talc, silica, barium sulfate, potassium feldspar, aluminum hydroxide, magnesium carbonate, mica, carbon black, red iron oxide, titanium oxide, phthalocyanine blue, kaolin, and gypsum. Zinc oxide and talc are particularly preferred. Examples of anti-settling agents and anti-sagging agents other than thermoplastic resins include bentonite, finely divided silica, stearates, lecithins, and alkyl sulfonates.

[0105] The content of copolymer (X) in the coating composition is preferably 10 to 65 mass%, more preferably 15 to 60 mass%, and even more preferably 20 to 55 mass%, based on the total mass of the coating composition. When the content of copolymer (X) is equal to or greater than the lower limit, the antifouling properties are more excellent. When the content of copolymer (X) is equal to or less than the upper limit, the coatability of the coating composition is more excellent.

[0106] The content of the organic solvent in the coating composition may be any amount so long as the VOC content is 500 g / L or less, and is preferably 10 to 50 mass %, more preferably 15 to 50 mass %, and even more preferably 20 to 45 mass %, relative to the total mass of the coating composition. If the content of the organic solvent is equal to or less than the upper limit, the VOC content will be sufficiently low. If the content of the organic solvent is equal to or greater than the lower limit, the viscosity of the coating composition will be easily reduced.

[0107] When the coating composition contains silicone oil, the content of the silicone oil in the coating composition is preferably 0.1 to 40 mass %, more preferably 1 to 20 mass %, based on the total mass of the coating composition. When the content of the silicone oil is equal to or greater than the lower limit, the antifouling properties are more excellent. When the content of the silicone oil is equal to or less than the upper limit, the dissolution stability of the coating film is more excellent.

[0108] When the coating composition contains an antifouling agent, the content of the antifouling agent in the coating composition is not particularly limited, but is preferably 10 to 200 parts by mass, more preferably 50 to 150 parts by mass, per 100 parts by mass of copolymer (X). When the content of the antifouling agent is equal to or greater than the lower limit, the antifouling effect of the coating film formed by the coating composition is superior. When the content of the antifouling agent is equal to or less than the upper limit, the physical properties of the coating film are superior.

[0109] The solid content (heating residue) of the coating composition may be an amount that results in a VOC content of 500 g / L or less, and is preferably 50 to 85 mass %, more preferably 55 to 80 mass %, and even more preferably 55 to 75 mass %, relative to the total mass of the coating composition. If the solid content is equal to or greater than the lower limit, the VOC content will be sufficiently low. If the solid content is equal to or less than the upper limit, the viscosity of the coating composition will be easily reduced.

[0110] The VOC content of the coating composition is 500 g / L or less, preferably 480 g / L or less, more preferably 440 g / L or less, and even more preferably 420 g / L or less. If the VOC content is below the upper limit, the amount of volatilized organic solvent can be sufficiently suppressed. In terms of the viscosity and coatability of the coating composition, the VOC content of the coating composition is preferably 350 g / L or more. The method for measuring the VOC content is the same as above.

[0111] The B-type viscosity of the coating composition at 25°C is preferably less than 5000 mPa·s, more preferably less than 3000 mPa·s, and even more preferably less than 1000 mPa·s. If the viscosity of the coating composition is equal to or less than the above upper limit, coating is easy. There is no particular restriction on the lower limit of the B-type viscosity of the coating composition at 25°C, but from the viewpoint of coating film properties, the Gardner viscosity at 25°C is preferably B or higher, and preferably 100 mPa·s or higher.

[0112] The coating composition can be prepared, for example, by preparing the resin composition of this embodiment as described above, and then adding other components and an additional organic solvent as necessary, and mixing them in. In this case, the VOC content and viscosity of the coating composition can be adjusted by adjusting the viscosity of the resin composition, the amount of organic solvent added to the resin composition, etc.

[0113] The coating composition can be used to form a coating film (antifouling coating film) on the surface of a substrate such as a ship, various fishing nets, port facilities, oil fences, bridges, or underwater structures such as an undersea base. A coating film using the coating composition can be formed directly on the substrate surface or via a base coating film. The base coating film can be formed using a wash primer, a chlorinated rubber-based or epoxy-based primer, or an intermediate coating. The coating film can be formed by a known method. For example, the coating composition can be applied to the surface of the substrate or onto a base coating film on the substrate by brush coating, spray coating, roller coating, immersion coating, or the like, and then dried to form a coating film. The amount of coating composition applied can generally be set to an amount that will result in a dried coating film thickness of 10 to 400 μm. The coating film can usually be dried at room temperature, or, if necessary, by heating.

[0114] <Action and Effect> In the coating composition described above, copolymer (X) has a specific composition (content of structural unit (A) of 5 to 35% by mass, content of structural unit (B) of 35 to 75% by mass, content of structural units based on (meth)acrylic macromonomers of less than 13% by mass) and a weight-average molecular weight of 2,000 or more and 6,500 or less, and therefore, like resin composition (1) or (2) described above, it is possible to form a coating film that exhibits excellent transparency and antifouling effect, and further, the coating composition is resistant to thickening during storage and has excellent storage stability.

[0115] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the examples, "parts" refers to "parts by mass." Evaluations in the examples were performed by the following methods.

[0116] (Solid content (heating residue)) 0.50 g of sample (resin composition) was weighed into an aluminum dish, and 3 mL of toluene was added using a dropper and spread evenly across the bottom of the dish, followed by pre-drying. Pre-drying is a treatment in which the sample is spread over the entire dish, making it easier to volatilize the solvent during main drying. In pre-drying, the sample and toluene were heated and dissolved in a water bath at 70 to 80°C, and evaporated to dryness. After pre-drying, main drying was carried out for 2 hours in a hot air dryer at 105°C. The solid content (heating residue) was calculated from the mass of the sample before pre-drying (mass before drying) and the mass after main drying (mass after drying) using the following formula: Solid content (mass %) = Mass after drying (g) / Mass before drying (g) × 100

[0117] (B-type Viscosity) The viscosity of a sample was measured at 25° C. using a B-type viscometer, and the measured value was shown as the B-type viscosity.

[0118] (Gardner Viscosity) A sample was placed in a dry Gardner bubble viscosity tube (hereinafter simply referred to as a "viscosity tube") up to the indicator line and then corked with a cork. The viscosity tube containing the sample was immersed vertically in a thermostatic water bath adjusted to a specified temperature (25.0±0.1°C) for at least 2 hours to keep the sample at a constant temperature. The viscosity tube serving as a reference tube and the viscosity tube containing the sample were simultaneously rotated 180°, and the viscosity (Gardner viscosity) was determined by comparing the bubble rise rate of the sample with that of the reference tube.

[0119] (Acid value of measurement solution) Approximately 4.0 g of sample (resin composition) was accurately weighed into a beaker (A (g)), and 50 mL of a 50 / 50 toluene / 95% ethanol solution was added. After stirring for 5 minutes in a sealed container, a Hiranuma automatic titrator (AUTO TITRATOR COM-1600) was used to perform potentiometric titration with a 0.5 mol / L potassium hydroxide solution (ethanol solution) manufactured by Kishida Chemical Co., Ltd., with a factor (f) of 1.003 at 20°C. The maximum slope of the titration curve was defined as the endpoint (titer amount = B (mL), titer of KOH solution = f). A blank measurement was also performed in the same manner (titer amount = C (mL)), and the acid value was calculated according to the following formula: Acid value of measurement solution (mg KOH / g) = {(B - C) x 0.5 x 56.11 x f} / A /

[0120] (Weight-average molecular weight (Mw), number-average molecular weight (Mn)) The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the polymer were measured using gel permeation chromatography (GPC) (HLC-8220, manufactured by Tosoh Corporation). The columns used were TSKgel α-M (7.8 mm × 30 cm, manufactured by Tosoh Corporation) and TSKguard column α (6.0 mm × 4 cm, manufactured by Tosoh Corporation). A calibration curve was prepared using F288 / F1 / F28 / F80 / F40 / F20 / F2 / A1000 (standard polystyrene, manufactured by Tosoh Corporation) and styrene monomer.

[0121] (VOC Content) The VOC content of the resin composition was calculated using the following formula: VOC content (g / L) = specific gravity of composition × 1000 × (100 - solid content) / 100 The method for measuring the solid content was as described above. The specific gravity was calculated by filling a 100 mL specific gravity cup with the resin composition at 25°C and measuring the mass.

[0122] (Storage Stability of Resin Composition) The viscosity change rate was determined as an index of the storage stability of the resin composition by the following method. The B-type viscosity (B-type viscosity before storage) (mPa·s) of the produced resin composition was measured. This resin composition was placed in a 150 mL glass bottle and stored at 25°C for 10 days. Thereafter, the B-type viscosity (B-type viscosity after storage) (mPa·s) of the resin composition was measured, and the viscosity change rate (%) was calculated using the following formula: Viscosity change rate (%) = B-type viscosity after storage (mPa·s) / B-type viscosity before storage (mPa·s) × 100

[0123] (Coating Wear Test) The produced resin composition was applied to a 50 mm x 50 mm x 2 mm (thickness) hard vinyl chloride plate with an applicator so that the dry film thickness was 120 μm, and then dried to form a coating film, thereby obtaining a test plate. This test plate was attached to a rotating drum placed in seawater and rotated at a peripheral speed of 7.7 m / s (15 knots). This state was maintained for three months, and the film thickness (μm) of the coating film three months after installation was measured. From the measured film thickness, the worn film thickness after three months (120 μm - measured film thickness) was calculated, and this value was taken as the wear value.

[0124] (Visual inspection of coating film appearance) The resin composition thus produced was applied to a glass plate using an applicator so as to have a dry film thickness of about 130 μm, and then dried to form a coating film, thereby obtaining a test plate. The appearance of this test plate was visually observed to confirm whether it was cloudy or not.

[0125] (Haze Value of Coating Film) The haze value of the test plate used for visually evaluating the appearance of the coating film was measured in accordance with JIS K 7136 using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., product name "Haze Meter NDH8000").

[0126] (Static Antifouling Property) The produced resin composition was applied with a brush to a sandblasted steel plate that had previously been coated with an anti-rust paint so that the dry film thickness was 200 to 300 μm, and then dried to form a coating film to obtain a test plate. After leaving this test plate stationary for 6 months, the ratio of the area where marine organisms had attached to the total area of ​​the coating film (marine organism attachment area) was determined, and the static antifouling property was evaluated according to the following criteria: ◎: The area where marine organisms had attached was 10% or less. ○: The area where marine organisms had attached was more than 10% and 20% or less. △: The area where marine organisms had attached was more than 20% and 40% or less. ×: The area where marine organisms had attached was more than 40%.

[0127] (Materials Used) PGM: Propylene glycol methyl ether. Monomer (M1): Metal atom-containing polymerizable monomer mixture synthesized in Production Example M1 described below. Monomer (M2): Metal atom-containing polymerizable monomer mixture synthesized in Production Example M2 described below. FM-0711: Trade name, manufactured by JNC Corporation (a polysiloxane block-containing polymerizable monomer in the formula (b1) where v=0, R3a to R3f=methyl groups, w=3, and x=10). X-24-8201: Trade name, manufactured by Shin-Etsu Chemical Co., Ltd. (a polysiloxane block-containing polymerizable monomer in the formula (b1) where v=0, R3a to R3f=methyl groups, w=3, and x=25). FM-7721: Trade name, manufactured by JNC Corporation (a polysiloxane block-containing polymerizable monomer in the formula (b4) where l and q = 0, m and o = 3, R1a to R1f = methyl groups, and n = 65). MMA: methyl methacrylate. EA: ethyl acrylate. MTA: 2-methoxyethyl acrylate. BA: n-butyl acrylate. MMA-MM: methyl methacrylate macromonomer synthesized using MMA-MM in Production Example 1 described below. AIBN: 2,2'-azobisisobutyronitrile. AMBN: 2,2'-azobis(2-methylbutyronitrile). Nofmer MSD: Trade name, manufactured by NOF Corporation, α-methylstyrene dimer.

[0128] [Production Example M1] A reaction vessel equipped with a stirrer, a temperature regulator, and a dropping funnel was charged with 85.4 parts of PGM and 40.7 parts of zinc oxide, and the mixture was heated to 75°C with stirring. Subsequently, a mixture of 43.1 parts of methacrylic acid, 36.1 parts of acrylic acid, and 5 parts of water was added dropwise from the dropping funnel at a constant rate over 3 hours. After stirring for a further 2 hours, 36 parts of PGM was added to obtain a transparent metal atom-containing polymerizable monomer mixture (monomer (M1)) with a solids content of 44.8% by mass.

[0129] [Production Example M2] A reaction vessel equipped with a stirrer, a temperature regulator, and a dropping funnel was charged with 72.4 parts of PGM and 40.7 parts of zinc oxide, and the mixture was heated to 75°C with stirring. Subsequently, a mixture of 30.1 parts of methacrylic acid, 25.2 parts of acrylic acid, and 51.6 parts of Versatic acid was added dropwise at a constant rate over 3 hours from the dropping funnel. After stirring for another 2 hours, 11 parts of PGM was added to obtain a transparent metal atom-containing polymerizable monomer mixture (monomer (M2)) with a solids content of 59.6% by mass.

[0130] [Production Example MMA-MM] 900 parts of deionized water, 60 parts of 2-sulfoethyl sodium methacrylate, 10 parts of potassium methacrylate, and 12 parts of methyl methacrylate (MMA) were placed in a polymerization apparatus equipped with a stirrer, a cooling tube, and a thermometer and stirred. The atmosphere inside the polymerization apparatus was replaced with nitrogen and the temperature was raised to 50°C. 0.08 parts of 2,2'-azobis(2-methylpropionamidine) dihydrochloride was added as a polymerization initiator, and the temperature was further raised to 60°C. After the temperature was raised, MMA was continuously added dropwise at a rate of 0.24 parts / min for 75 minutes using a dropping pump. The reaction solution was maintained at 60°C for 6 hours and then cooled to room temperature to obtain Dispersant 1, which was a transparent aqueous solution with a solids content of 10% by mass.

[0131] Next, 145 parts of deionized water, 0.1 parts of sodium sulfate, and 0.25 parts of Dispersant 1 (solid content 10% by mass) were placed in a polymerization apparatus equipped with a stirrer, a cooling tube, and a thermometer and stirred to form a uniform aqueous solution. Next, 100 parts of MMA, 0.008 parts of bis[(difluoroboryl)diphenylglyoximate]cobalt(II) as a chain transfer agent, and 0.8 parts of "Perocta O" (registered trademark) (1,1,3,3-tetramethylbutylperoxy 2-ethylhexanoate, manufactured by NOF Corporation) as a polymerization initiator were added to form an aqueous suspension.

[0132] Next, the inside of the polymerization reactor was purged with nitrogen, the temperature was raised to 80°C, and the reaction was carried out for 4 hours. To further increase the polymerization rate, the temperature was raised to 90°C and maintained at this temperature for 2 hours. Thereafter, the reaction solution was cooled to 40°C to obtain an aqueous suspension containing the macromonomer. This aqueous suspension was filtered, and the filtrate was washed with deionized water, dehydrated, and dried at 40°C for 16 hours to obtain a macromonomer (MMA-MM). The number average molecular weight of the obtained MMA-MM was 1,600, and the molecular weight distribution (Mw / Mn) was 2.0.

[0133] [Production Example A-1] A reaction vessel equipped with a stirrer, temperature regulator, and dropping device was charged with 30 parts of xylene, 15 parts of n-butanol, and 4 parts of EA, and the temperature was raised to 100 ° C. while stirring. Subsequently, a mixture consisting of 26.6 parts of monomer (M1) (12 parts in terms of solids), 40 parts of FM-0711, 30.3 parts of MMA, 13.9 parts of EA, 1 part of AIBN, 7.5 parts of AMBN, and 1.5 parts of Nofumer MSD was added dropwise at a constant rate over 6 hours from the dropping funnel. After completion of the dropwise addition, 0.5 parts of tert-butyl peroxyoctoate and 4.0 parts of xylene were added dropwise at a constant rate over 30 minutes. After further stirring for 1 hour, 16.4 parts of xylene was added. This yielded a resin composition A-1 containing a copolymer. Table 1 shows the evaluation results of the properties of Resin Composition A-1 (solid content, acid value of the measured solution, Gardner viscosity immediately after production (hereinafter also referred to as "initial viscosity"), weight average molecular weight, number average molecular weight and film haze value of the copolymer contained therein), storage stability (rate of viscosity change) and coating film performance (degree of wear).

[0134] [Production Examples A-2 to A-15] Resin compositions A-2 to A-15 were produced in the same manner as in Production Example A-1, except that the type and amount of monomer and the type and amount of initiator were as shown in Tables 1 to 3, and the amount of xylene after completion of dropwise addition was adjusted according to the amount of additive so that the theoretical solid content was 55% by mass. Tables 1 to 3 show the evaluation results of the properties (solid content, initial viscosity, weight average molecular weight and number average molecular weight of the copolymer contained) and storage stability (viscosity change rate) of resin compositions A-2 to A-15.

[0135] In Tables 1 to 3, the numerical values ​​shown in the columns for monomer and initiator indicate the amount (parts) charged. For the amounts of monomers (M1) and (M2) charged, the values ​​shown in parentheses are the amounts charged in solid content, and the values ​​shown above them are the total amounts charged including the organic solvent.

[0136]

[0137]

[0138]

[0139] [Examples 1 to 11, Comparative Examples 1 to 4] Table 4 shows Examples 1 to 11 and Comparative Examples 1 to 4 using resin compositions A-1 to A-15. In Table 4, the numerical values ​​listed in the composition column indicate the blend amount (parts). The blend amount of the resin composition is the amount of the entire resin composition. Table 4 shows the evaluation results of the coating film performance (wear rate, static soil resistance, and visual appearance) of the coating films obtained from the listed resin compositions. In addition, for Example 1, Example 11, and Comparative Example 4, the evaluation results of the film haze value of the coating films obtained from the listed resin compositions are shown.

[0140]

[0141] Resin compositions A-1 to A-6 and A-10 to A-14 exhibited excellent storage stability with minimal change in viscosity during storage. Furthermore, the coating films of these resin compositions had an appropriate wear rate. Furthermore, the coating films of Examples 1 to 11 using these resin compositions exhibited excellent static soil resistance, favorable visual appearance evaluations, and excellent light transmittance. Furthermore, the coating films of Examples 1 and 11 obtained from resin compositions A-1 and A-14 exhibited excellent light transmittance, as evidenced by their low film haze values. On the other hand, resin composition A-7, in which the content of structural unit (B) in the copolymer was less than 35% by mass, exhibited high viscosity, poor performance under low VOC conditions, and poor storage stability. Resin composition A-8, in which the weight-average molecular weight of the copolymer was greater than 6,500, exhibited poor storage stability. Resin composition A-9, in which the weight-average molecular weight of the copolymer was lower than that of resin composition A-7, exhibited improved storage stability, but the coating film wear rate was too high, resulting in poor long-term soil resistance. This was also confirmed by the evaluation results of static antifouling properties in Comparative Example 3, which used Resin Composition A-9. The coating film obtained from Resin Composition A-15, in which the content of structural units based on MMA-MM in the copolymer was 13 mass % or more, had a high film haze value and poor light transmittance.

[0142] According to the present invention, a resin composition can be provided that can form a coating film that exhibits excellent antifouling effect, is resistant to thickening during storage, and has excellent storage stability. The coating film obtained using the resin composition of the present invention can be suitably used to prevent adhesion of marine organisms.

Claims

1. A resin composition comprising: a (meth)acrylic copolymer including a structural unit (A) based on a metal atom-containing polymerizable monomer (a) containing a structure represented by the following formula (1) or (2) and an ethylenically unsaturated bond, and a structural unit (B) based on at least one polysiloxane block-containing polymerizable monomer (b) selected from the group consisting of a polymerizable monomer represented by the following formula (b1), a polymerizable monomer represented by the following formula (b2), a polymerizable monomer represented by the following formula (b3), and a polymerizable monomer represented by the following formula (b4), and an organic solvent, wherein the content of the structural unit (A) is 5 to 35 mass%, the content of the structural unit (B) is 35 to 75 mass%, and the content of the structural unit based on a (meth)acrylic macromonomer is less than 13 mass%, relative to the total mass of all structural units constituting the (meth)acrylic copolymer, and the weight average molecular weight of the (meth)acrylic copolymer is 2,000 or more and 6,500 or less, A resin composition having a VOC content of 500 g / L or less. ０ ... (2) CH ２ =CR ３ａ -CO-O-(C ｕ H ２ｕ -O) ｖ -C ｗ H ２ｗ -(SiR ３ｂ R ３ｃ -O) ｘ -SiR ３ｄ R ３ｅ R ３ｆ ... (b1) CH ２ =CR ４ａ -CO-O-(C ｕ’ H ２ｕ’ -O) ｖ’ -C ｗ’ H ２ｗ’ -Si(OSiR ４ｂ R ４ｃ R ４ｄ ) ３ ... (b2) CH ２ =CR ２ａ -CO-O-(C ｋ’ H ２ｋ’ -O) ｌ’ -C ｍ’ H ２ｍ’ -Si((OSiR ２ｂ R ２ｃ ) ｒ -OSiR ２ｄ R ２ｅ R ２ｆ ) ２ -OSi((OSiR ２ｇ R ２ｈ ) ｓ -OSiR ２ｉ R ２ｊ R ２ｋ ) ２ -C о’ H ２о’ -(O-C ｐ’ H ２ｐ’ ) ｑ’ -O-CO-CR ２ｌ =CH ２ ... (b3) CH ２ =CR １ａ -CO-O-(C ｋ H ２ｋ -O) ｌ -C ｍ H ２ｍ -(SiR １ｂ R １ｃ -O) ｎ -SiR １ｄ R １ｅ -C о H ２о -(O-C ｐ H ２ｐ ) ｑ -O-CO-CR １ｆ =CH ２ ... (b4) (wherein M represents Zn, Cu, Mg, or Ca, and R ０ represents a monovalent organic acid residue, R ３ａ represents a hydrogen atom or a methyl group, u represents an integer of 2 to 5, v represents a number of 0 to 50, w represents an integer of 2 to 5, x represents a number of 3 to 80, R ３ｂ ~R ３ｆ each independently represents an alkyl group, an alkoxy group, a phenyl group, a substituted phenyl group, a phenoxy group or a substituted phenoxy group; R ４ａ represents a hydrogen atom or a methyl group, u' represents an integer of 2 to 5, v' represents a number of 0 to 50, w' represents an integer of 2 to 5, R ４ｂ ~R ４ｄ each independently represents an alkyl group, -(OSiR ５１ R ５２ ) ｙ -OSiR ５３ R ５４ R ５５ (wherein y is an integer from 0 to 20, R ５１ ~R ５５ represents an alkyl group; ５６ - (OC ２ H ４ ) ｙ’ -OR ５７ (wherein y′ represents an integer from 1 to 20, R ５６ represents an alkylene group; R ５７ represents an alkyl group; R ２ａ and R ２ｌ each independently represents a hydrogen atom or a methyl group; k' and p' each independently represents an integer of 2 to 5; l' and q' each independently represents a number of 0 to 50; m' and o' each independently represents an integer of 2 to 5; r and s each independently represents a number of 0 to 20; R ２ｂ ~R ２ｋ each independently represents an alkyl group; R １ａ and R １ｆ each independently represents a hydrogen atom or a methyl group; k and p each independently represent an integer of 2 to 5; l and q each independently represent a number of 0 to 50; m and o each independently represent an integer of 2 to 5; n represents a number of 3 to 80; R １ｂ ~R １ｅ each independently represents an alkyl group, an alkoxy group, a phenyl group, a substituted phenyl group, a phenoxy group or a substituted phenoxy group.

2. The resin composition according to claim 1, wherein the content of the (meth)acrylic copolymer is 10 to 65% by mass based on the total mass of the resin composition.

3. A resin composition comprising: a (meth)acrylic copolymer containing a structural unit (A) based on a metal atom-containing polymerizable monomer (a) containing a structure represented by the following formula (1) or (2) and an ethylenically unsaturated bond, and a structural unit (B) based on at least one polysiloxane block-containing polymerizable monomer (b) selected from the group consisting of a polymerizable monomer represented by the following formula (b1), a polymerizable monomer represented by the following formula (b2), a polymerizable monomer represented by the following formula (b3), and a polymerizable monomer represented by the following formula (b4), and an organic solvent, wherein the content of the structural unit (A) is 5 to 35 mass%, the content of the structural unit (B) is 35 to 75 mass%, and the content of the structural unit based on a (meth)acrylic macromonomer is less than 13 mass%, relative to the total mass of all structural units constituting the (meth)acrylic copolymer, and the weight average molecular weight of the (meth)acrylic copolymer is 2,000 to 6,500, A resin composition, wherein the content of the organic solvent is 50% by mass or less with respect to the total mass of the resin composition, and the viscosity measured by a Gardner bubble viscometer at 25° C. and a solid content concentration of 50% by mass is Z or less. ０ ... (2) CH ２ =CR ３ａ -CO-O-(C ｕ H ２ｕ -O) ｖ -C ｗ H ２ｗ -(SiR ３ｂ R ３ｃ -O) ｘ -SiR ３ｄ R ３ｅ R ３ｆ ... (b1) CH ２ =CR ４ａ -CO-O-(C ｕ’ H ２ｕ’ -O) ｖ’ -C ｗ’ H ２ｗ’ -Si(OSiR ４ｂ R ４ｃ R ４ｄ ) ３ ... (b2) CH ２ =CR ２ａ -CO-O-(C ｋ’ H ２ｋ’ -O) ｌ’ -C ｍ’ H ２ｍ’ -Si((OSiR ２ｂ R ２ｃ ) ｒ -OSiR ２ｄ R ２ｅ R ２ｆ ) ２ -OSi((OSiR ２ｇ R ２ｈ ) ｓ -OSiR ２ｉ R ２ｊ R ２ｋ ) ２ -C о’ H ２о’ -(O-C ｐ’ H ２ｐ’ ) ｑ’ -O-CO-CR ２ｌ =CH ２ ... (b3) CH ２ =CR １ａ -CO-O-(C ｋ H ２ｋ -O) ｌ -C ｍ H ２ｍ -(SiR １ｂ R １ｃ -O) ｎ -SiR １ｄ R １ｅ -C о H ２о -(O-C ｐ H ２ｐ ) ｑ -O-CO-CR １ｆ =CH ２ ... (b4) (wherein M represents Zn, Cu, Mg, or Ca, and R ０ represents a monovalent organic acid residue, R ３ａ represents a hydrogen atom or a methyl group, u represents an integer of 2 to 5, v represents a number of 0 to 50, w represents an integer of 2 to 5, x represents a number of 3 to 80, R ３ｂ ~R ３ｆ each independently represents an alkyl group, an alkoxy group, a phenyl group, a substituted phenyl group, a phenoxy group or a substituted phenoxy group; R ４ａ represents a hydrogen atom or a methyl group, u' represents an integer of 2 to 5, v' represents a number of 0 to 50, w' represents an integer of 2 to 5, R ４ｂ ~R ４ｄ each independently represents an alkyl group, -(OSiR ５１ R ５２ ) ｙ -OSiR ５３ R ５４ R ５５ (wherein y is an integer from 0 to 20, R ５１ ~R ５５ represents an alkyl group; ５６ - (OC ２ H ４ ) ｙ’ -OR ５７ (wherein y′ represents an integer from 1 to 20, R ５６ represents an alkylene group; R ５７ represents an alkyl group; R ２ａ and R ２ｌ each independently represents a hydrogen atom or a methyl group; k' and p' each independently represents an integer of 2 to 5; l' and q' each independently represents a number of 0 to 50; m' and o' each independently represents an integer of 2 to 5; r and s each independently represents a number of 0 to 20; R ２ｂ ~R ２ｋ each independently represents an alkyl group; R １ａ and R １ｆ each independently represents a hydrogen atom or a methyl group; k and p each independently represent an integer of 2 to 5; l and q each independently represent a number of 0 to 50; m and o each independently represent an integer of 2 to 5; n represents a number of 3 to 80; R １ｂ ~R １ｅ each independently represents an alkyl group, an alkoxy group, a phenyl group, a substituted phenyl group, a phenoxy group or a substituted phenoxy group.

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