Copolymer for antifouling coating composition, antifouling coating composition

Abstract

Provided is an antifouling coating composition that can exhibit excellent properties even when an antifouling coating film has been repeatedly applied, without a deterioration in the dissolution stability of the coating film and without the occurrence of coating film abnormalities such as peeling and cracking.　The present invention provides a copolymer for antifouling coating compositions wherein the copolymer A for antifouling coating compositions is obtained by the copolymerization of a monomer mixture comprising a monomer (a), a monomer (b), and a monomer (c); the monomer (a) is given by general formula (1); the monomer (b) is given by general formula (2); the monomer (c) is a monomer other than the monomer (a) and monomer (b), that is copolymerizable with the monomer (a) and monomer (b); the proportion of the monomer (a) in the monomer mixture is 25-60 mass%; the copolymer has a molecular weight distribution (Mw / Mn) of at least 5.0; and the copolymer does not contain the sulfur atom.

Description

[Technical Field]

[0001] The present invention relates to a copolymer for an antifouling coating composition, and an antifouling coating composition. [Background technology]

[0002] Aquatic fouling organisms such as barnacles, serpula, mussels, bryozoans, sea squirts, green laver, sea lettuce, slime, etc. attach to ships (especially the bottom of ships), fishing equipment such as fishing nets and fishing net accessories, and underwater structures such as power plant water pipes, causing problems such as impairing the function of these ships and damaging their appearance. To prevent such problems, a technique is known in which an antifouling coating composition is applied to a ship or the like to form an antifouling coating film, and an antifouling agent is gradually released from the antifouling coating film, thereby providing antifouling performance over a long period of time (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-17203 Summary of the Invention [Problem to be solved by the invention]

[0004] However, even with the technology of Patent Document 1, repainting (repainting) is required to achieve long-term antifouling performance of five years or more, but after operation following prolonged contact with seawater, water penetrates into the antifouling coating film and the coating deteriorates, resulting in a decrease in adhesion. In particular, even with paints of the same composition, the surface of the old coating tends to become hydrophilic due to deterioration from prolonged contact with seawater, and the coating may assume a state different from the original properties of the original coating, which can affect the performance of the coating formed from the paint applied on top.

[0005] The present invention has been made in view of the above circumstances, and provides a copolymer for an antifouling coating composition that can exhibit good performance even when the antifouling coating film is recoated without deteriorating the dissolution stability of the coating film or causing coating film abnormalities such as peeling or cracking. [Means for solving the problem]

[0006] According to the present invention, there is provided a copolymer A for an antifouling coating composition obtained by copolymerizing a monomer mixture composed of monomer (a), monomer (b), and monomer (c), wherein the monomer (a) is represented by general formula (1), the monomer (b) is represented by general formula (2), the monomer (c) is a monomer other than the monomer (a) and the monomer (b) that is copolymerizable with the monomer (a) and the monomer (b), the proportion of the monomer (a) in the monomer mixture is 25 to 60 mass%, the copolymer has a molecular weight distribution (Mw / Mn) of 5.0 or more, and the copolymer does not contain a sulfur atom.

[0007] As a result of extensive research into solving the above problems, the present inventors have found that the problems can be solved by controlling the molecular weight distribution (Mw / Mn) of a copolymer containing a specific component, and have thus completed the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0008] The present invention will be described in detail below.

[0009] 1. Antifouling paint composition The antifouling coating composition of the present invention contains copolymer A.

[0010] 1-1.Copolymer A Copolymer A is obtained by copolymerizing a monomer mixture composed of monomer (a), monomer (b), and monomer (c). Copolymer A is a (meth)acrylate triorganosilyl group-containing copolymer. The monomers (a) to (c) and a method for synthesizing copolymer A will be specifically described below. In this specification, the term "(meth)acrylic acid" means acrylic acid or methacrylic acid, and the term "(meth)acrylate" means acrylate or methacrylate.

[0011] <Monomer (a)> The monomer (a) is a triorganosilyl (meth)acrylate monomer and is represented by the general formula (1). [ka] (In the formula, R 1 is hydrogen or a methyl group, and R 2 ~R 4 are the same or different and each represents a branched alkyl group having 3 to 8 carbon atoms or a phenyl group.

[0012] R 2 ~R 4 The number of carbon atoms in is, for example, 3, 4, 5, 6, 7, or 8, and may be within a range between any two of the values ​​exemplified here. Examples of branched alkyl groups include an isopropyl group, an isopropenyl group, an isobutyl group, an s-butyl group, a t-butyl group, a 1-ethylpropyl group, a 1-methylbutyl group, a 1-methylpentyl group, a 1,1-dimethylpropyl group, a 1,1-dimethylbutyl group, a thexyl group, a cyclohexyl group, a 1,1-dimethylpentyl group, a 1-methylhexyl group, a 1,1-dimethylhexyl group, a 1-methylheptyl group, a 2-methylbutyl group, a 2-ethylbutyl group, a 2,2-dimethylpropyl group, a cyclohexylmethyl group, a 2-ethylhexyl group, a 2-propylpentyl group, and a 3-methylpentyl group. 2 ~R 4are preferably the same or different and are an isopropyl group, an isopropenyl group, an s-butyl group, a t-butyl group, a phenyl group, and a 2-ethylhexyl group, and particularly preferably are an isopropyl group and a 2-ethylhexyl group.

[0013] Examples of the monomer (a) include triisopropylsilyl (meth)acrylate, triisopropenylsilyl (meth)acrylate, triisobutylsilyl (meth)acrylate, tri-s-butylsilyl (meth)acrylate, triisopentylsilyl (meth)acrylate, triphenylsilyl (meth)acrylate, diisopropylisopropenylsilyl (meth)acrylate, diisopropenylisopropylsilyl (meth)acrylate, diisopropylphenylsilyl (meth)acrylate, diisopropylisobutylsilyl (meth)acrylate, diisopropyl-s-butylsilyl (meth)acrylate, diisopropylisopentylsilyl (meth)acrylate, isopropyldiisobutylsilyl (meth)acrylate, Examples thereof include isopropyldi-s-butylsilyl, t-butyldiisobutylsilyl (meth)acrylate, t-butyldiisopentylsilyl (meth)acrylate, t-butyldiphenylsilyl (meth)acrylate, diisopropylthexylsilyl (meth)acrylate, diisopropylcyclohexylsilyl (meth)acrylate, tricyclohexylsilyl (meth)acrylate, tri-1,1-dimethylpentylsilyl (meth)acrylate, tri-2,2-dimethylpropylsilyl (meth)acrylate, tricyclohexylmethylsilyl (meth)acrylate, diisopropylcyclohexylmethylsilyl (meth)acrylate, tri-2-ethylhexylsilyl (meth)acrylate, tri-2-propylpentylsilyl (meth)acrylate, etc. Preferred examples thereof include triisopropylsilyl (meth)acrylate, tri-s-butylsilyl (meth)acrylate, t-butyldiphenylsilyl (meth)acrylate, and tri-2-ethylhexylsilyl (meth)acrylate. These monomers (a) can be used alone or in combination of two or more.

[0014] <Monomer (b)> The monomer (b) is represented by the chemical formula (2). [ka] (In the formula, R 5 is hydrogen or a methyl group, and R 6 is a hydrocarbon group having 2 to 9 carbon atoms and an oxygen atom.

[0015] Monomer (b) is R 6 It is a monomer that contains an oxygen atom in the moiety and is copolymerizable with the monomer (a).

[0016] R 6 The number of carbon atoms in R is, for example, 2, 3, 4, 5, 6, 7, 8, or 9, and may be within a range between any two of the values ​​exemplified here. 6 Examples of the hydrocarbon group include aliphatic hydrocarbon groups (e.g., alkyl groups) substituted with a substituent having an oxygen atom (e.g., hydroxyl group, alkoxy group), and aromatic hydrocarbon groups having an aromatic ring containing an oxygen atom.

[0017] Examples of the monomer (b) include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-methoxypropyl (meth)acrylate, 4-methoxybutyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, diethylene glycol monomethyl (meth)acrylate, propylene glycol monomethyl (meth)acrylate, oligo(ethylene glycol) methyl ether (meth)acrylate, oligo(ethylene glycol) ethyl ether (meth)acrylate, glycidyl (meth)acrylate, furfuryl (meth)acrylate, and tetrahydrofurfuryl (meth)acrylate.

[0018] From the viewpoint of dissolution stability, the monomer (b) preferably has an ether bond. From the viewpoint of coating film properties, the monomer (b) is more preferably 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, or 2-(2-ethoxyethoxy)ethyl (meth)acrylate. The monomer (b) can be used alone or in combination as a monomer component of the copolymer A.

[0019] <Monomer (c)> The monomer (c) is a monomer other than the monomer (a) and the monomer (b) that is copolymerizable with the monomer (a) and the monomer (b). The monomer (c) is preferably an ethylenically unsaturated monomer.

[0020] Examples of the monomer (c) include (meth)acrylic acid esters such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, zinc (meth)acrylate, copper (meth)acrylate, zinc versatate (meth)acrylate, copper versatate (meth)acrylate, zinc naphthenate (meth)acrylate, copper naphthenate (meth)acrylate, zinc stearate (meth)acrylate, and copper abietic (meth)acrylate. vinyl compounds such as vinyl chloride, vinylidene chloride, (meth)acrylonitrile, vinyl acetate, vinyl alcohol, butyl vinyl ether, isobutyl vinyl ether, lauryl vinyl ether, N-vinylpyrrolidone, and vinyl sulfonic acid; Aromatic compounds such as styrene, vinyltoluene, α-methylstyrene, vinylbenzenesulfonic acid, and vinyl benzoate Dibasic acid dialkyl ester compounds such as dimethyl maleate, dibutyl maleate, and dimethyl fumarate (Meth)acrylic acid, 2-carboxyethyl (meth)acrylate, and other unsaturated monocarboxylic acid compounds Compounds with zwitterionic structures, such as (meth)acrylate oxyethyl phosphorylcholine, 3-[[2-(methacryloyloxy)ethyl]dimethylammonio]propionate, 3-[[2-(methacryloyloxy)ethyl]dimethylammonio]propane-1-sulfonic acid, and 3-[(3-acrylamidopropyl)dimethylammonio]propanoate. Oligomers or polymers having unsaturated groups, such as AA-6 (manufactured by Toagosei Co., Ltd., methacryloyl-terminated polymethyl methacrylate), AS-6 (manufactured by Toagosei Co., Ltd., methacryloyl-terminated polystyrene), Silaplane FM-0711 (manufactured by JNC Corporation, one-terminated methacryloxy-terminated polydimethyl silicone), and KF-2012 (manufactured by Shin-Etsu Chemical Co., Ltd., one-terminated methacryloxy-terminated polydimethyl silicone). Examples include:

[0021] Among these, aromatic compounds and (meth)acrylic acid esters are particularly preferred, and styrene, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, t-butyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, zinc (meth)acrylate, zinc naphthenate (meth)acrylate, rosin zinc (meth)acrylate, hydrogenated rosin zinc (meth)acrylate, copper (meth)acrylate, copper naphthenate (meth)acrylate, rosin copper (meth)acrylate, and hydrogenated rosin copper (meth)acrylate are more preferred.

[0022] Monomer (c) can be used alone or in combination as a monomer component of copolymer A. Monomer (c) may contain a triorganosilyl (meth)acrylate other than monomer (a). The proportion of triorganosilyl (meth)acrylate other than monomer (a) in the monomer mixture is desirably 10 mass% or less. Examples of triorganosilyl (meth)acrylate other than monomer (a) include trimethylsilyl (meth)acrylate and triethylsilyl (meth)acrylate.

[0023] The proportion of monomer (a) in the monomer mixture is 25 to 60% by mass, and from the viewpoint of maintaining stable coating film solubility, it is preferably 30 to 55% by mass, and more preferably 35 to 50% by mass. Specific examples of this proportion include 25, 30, 35, 40, 45, 50, 55, and 60% by mass, and may be within a range between any two of the values ​​exemplified here.

[0024] The proportion of monomer (b) in the monomer mixture is preferably 5 to 55% by mass, and from the viewpoint of the balance between hydrophobicity and hydrophilicity of the copolymer, more preferably 5 to 50% by mass, and even more preferably 5 to 45% by mass. Specific examples of this proportion include 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, and 55% by mass, and may be within a range between any two of the values ​​exemplified here.

[0025] The weight-average molecular weight (Mw) of copolymer A is preferably 5,000 to 300,000. If the weight-average molecular weight (Mw) is less than 5,000, the coating film of the antifouling coating becomes brittle and prone to peeling and cracking, while if it exceeds 300,000, the viscosity of the copolymer solution increases, making it difficult to handle.

[0026] Specific examples of Mw include 5000, 10000, 20000, 30000, 40000, 50000, 60000, 70000, 80000, 90000, 100000, 200000, and 300000, and may be within a range between any two of the numerical values ​​exemplified here.

[0027] The molecular weight distribution (Mw / Mn) of the copolymer of the present invention is 5.0 or more. When it is within this range, crystallinity is alleviated, and the initial solubility of the coating film after drying is improved, and adhesion is improved. From the viewpoint of achieving the above effects more significantly and improving production efficiency, it is preferably 5.0 to 20.0, more preferably 6.0 to 12.0. Mw / Mn is, for example, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, 12.0, 13.0, 14.0, 15.0, 16.0, 17.0, 18.0, 19.0, or 20.0, and may be within a range between any two of the values ​​exemplified here.

[0028] The polymerization method for producing such a (meth)acrylic resin having a wide molecular weight distribution is not particularly limited. However, in a typical radical polymerization method in which one type of radical polymerization initiator is used and almost the entire amount of the initiator is added dropwise in one step together with a monomer mixture to carry out polymerization, there is no significant difference between the initiator concentration and the monomer concentration in the polymerization reaction system, and a copolymer having a molecular weight distribution (Mw / Mn) of 5.0 or more cannot be obtained.

[0029] Therefore, it is desirable to use a method of gradually changing the concentration of initiator or monomer using a dropping method or a shot addition method, a method of gradually changing the polymerization temperature, a method of using two or more appropriately selected initiators, a method of mixing two or more copolymers of the same composition but different molecular weights that have been produced separately, a method of adding a chain transfer agent in an appropriate amount at an appropriate time, a method of adding a polyfunctional monomer in an appropriate amount at an appropriate time, or an appropriate combination of these methods. For example, the molecular weight distribution can be broadened by carrying out polymerization at a very low concentration of polymerization initiator at the beginning of the polymerization to produce a very high molecular weight component, and then increasing the concentration of polymerization initiator to produce a low molecular weight component. Alternatively, the molecular weight distribution can be broadened by adding a chain transfer agent, for example, in the middle or later stages of the polymerization to lower the molecular weight of the polymer produced. According to such a method, the molecular weight distribution is broadened by increasing the amount of very high and very low molecular weight components.

[0030] By carrying out the above-described characteristic production method, it becomes easy to synthesize a copolymer having a molecular weight distribution (Mw / Mn) of 5.0 or more. The difference between the initiator concentration and the monomer concentration can be selected at any quantitative ratio at any stage, but from the viewpoint of temperature control in the polymerization reaction, particularly heat generation control, it is desirable to keep the initiator concentration low and the monomer concentration high in the early stage of polymerization.

[0031] The Mw and Mn can be measured by, for example, gel permeation chromatography (GPC). The molecular weight distribution (Mw / Mn) can be calculated using the Mw and Mn values ​​measured by the above-mentioned method.

[0032] Copolymer A may be any of a random copolymer, an alternating copolymer, a periodic copolymer, and a block copolymer.

[0033] Copolymer A can be obtained, for example, by polymerizing a monomer mixture composed of monomer (a), monomer (b) and monomer (c) in the presence of a polymerization initiator.

[0034] Examples of the polymerization initiator used in the polymerization reaction include azo compounds such as 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis-2-methylbutyronitrile (AMBN), and dimethyl-2,2'-azobisisobutyrate; and peroxides such as dibenzoyl peroxide, m-toluoyl peroxide, benzoyl m-methylbenzoyl peroxide, di-tert-butyl peroxide, tert-butyl peroxybenzoate, tert-butylperoxyisopropyl carbonate, tert-butyl peroctoate, tert-butylperoxy 2-ethylhexanoate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, and Nyper BMT-K40 (manufactured by NOF Corporation). Among these, it is particularly preferable to use AIBN, AMBN, dibenzoyl peroxide, m-toluoyl peroxide, benzoyl m-methylbenzoyl peroxide, tert-butyl peroctoate, and 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate. The polymerization initiators may be used alone or in combination of two or more. The type of polymerization initiator to be used is desirably selected taking into consideration the polymerization temperature. The amount of polymerization initiator used may be determined appropriately depending on the type and ratio of monomers, etc.

[0035] By appropriately setting the amount of polymerization initiator used, it is possible to adjust the molecular weight of copolymer A. Furthermore, as described above, it is also possible to adjust the molecular weight distribution (Mw / Mn) by adjusting the concentration of the initiator at each stage in the polymerization process or by using different types of initiator.

[0036] Furthermore, the molecular weight of copolymer A can be adjusted by adding a chain transfer agent or a polyfunctional monomer in an appropriate amount at an appropriate time, and the amount of initiator used can be reduced by using these additives. From this perspective, preferred chain transfer agents include α-methylstyrene dimer (NOFMER MSD, manufactured by NOF Corporation), 1,4-naphthoquinone, 2-hydroxy-1,4-naphthoquinone, and Quinopower QS-10 (manufactured by Kawasaki Chemical Industries, Ltd.).

[0037] The use of mercaptan chain transfer agents should be avoided because the physical properties (crack resistance) deteriorate if sulfur atoms are included as a component of copolymer A. Furthermore, compounds with mercapto groups or disulfide groups are not desirable in terms of production because of their characteristic odor.

[0038] Examples of the mercaptan-based chain transfer agent include monofunctional thiol compounds such as n-butyl mercaptan, n-octyl mercaptan, t-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, tridecyl mercaptan, tetradecyl mercaptan, hexadecyl mercaptan, β-mercaptopropionic acid, and 2-ethylhexyl thioglycolate, as well as bifunctional thiol compounds such as polysiloxanes modified with mercapto groups at both ends (manufactured by Shin-Etsu Chemical Co., Ltd.; X-22-167B), and side-chain multifunctional mercapto-modified polysiloxanes in which the side chains are modified with mercapto groups (manufactured by Shin-Etsu Chemical Co., Ltd.; KF-2001, KF-2004).

[0039] Examples of the polyfunctional monomer include 1,2-ethanediol di(meth)acrylate, 1,2-propanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, dipropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, trimethylolpropane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, and pentaerythritol tri(meth)acrylate. Examples include ethylene oxide-added bisphenol A di(meth)acrylate, ethylene oxide-added bisphenol F di(meth)acrylate, propylene oxide-added bisphenol A di(meth)acrylate, and propylene oxide-added bisphenol F di(meth)acrylate.

[0040] Examples of the polymerization method include solution polymerization, bulk polymerization, emulsion polymerization, suspension polymerization, non-aqueous dispersion polymerization, etc. Among these, solution polymerization or non-aqueous dispersion polymerization is particularly preferred because it allows copolymer A to be obtained easily and accurately.

[0041] In the polymerization reaction, an organic solvent may be used as needed. Examples of the organic solvent include aromatic hydrocarbon solvents such as xylene and toluene. Aliphatic hydrocarbon solvents such as hexane, heptane, octane, and mineral spirits; ester solvents such as ethyl acetate, butyl acetate, isobutyl acetate, and methoxypropyl acetate Alcohol-based solvents such as isopropyl alcohol, butyl alcohol, and propylene glycol monomethyl ether; Ether-based solvents such as dioxane, diethyl ether, and dibutyl ether ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone;

[0042] Among these, aliphatic hydrocarbon solvents, ester solvents, alcohol solvents, and aromatic hydrocarbon solvents are particularly preferred, and mineral spirits, butyl acetate, isobutyl acetate, butyl alcohol, propylene glycol monomethyl ether, toluene, and xylene are more preferred. These solvents can be used alone or in combination of two or more.

[0043] The reaction temperature in the polymerization reaction may be appropriately set depending on the type of polymerization initiator, etc., and is usually 60 to 150°C, and preferably 70 to 140°C.

[0044] The polymerization reaction is preferably carried out in an atmosphere of an inert gas such as nitrogen gas or argon gas.

[0045] 1-2. Antifouling agents Antifouling agents include, for example, inorganic agents and organic agents. Examples of inorganic agents include cuprous oxide, copper thiocyanate (common name: copper rhodanide), copper powder, etc. Among these, cuprous oxide and copper rhodanide are particularly preferred, and cuprous oxide that has been surface-treated with glycerin, sucrose, stearic acid, lauric acid, rishitin, mineral oil, etc. is more preferred in terms of long-term storage stability. Examples of organic agents include 2-mercaptopyridine-N-oxide copper (generic name: copper pyrithione), 2-mercaptopyridine-N-oxide zinc (generic name: zinc pyrithione), zinc ethylenebisdithiocarbamate (generic name: zineb), 4,5-dichloro-2-n-octyl-3-isothiazolone (generic name: She-Nine 211), 3,4-dichlorophenyl-NN-dimethylurea (generic name: diuron), 2-methylthio-4-t-butylamino-6-cyclopropylamino-s-triazine (generic name: Irgarol 1051), 2-(p-chlorophenyl)-3-cyano-4-bromo-5-trifluoromethylpyrrole (generic name: Econea 28), and 4-[1-(2,3-dimethylphenyl)ethyl]-1H-imidazole (generic name: medetomidine). These antifouling agents can be used alone or in combination of two or more.

[0046] The content of the antifouling agent in the composition of the present invention is not particularly limited, but is usually 0.1 to 60.0 mass % in terms of solid content. The content of the antifouling agent is, for example, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, or 60 mass %, and may be within a range between any two of the values ​​exemplified here.

[0047] 1-3. Other additives Furthermore, if necessary, components other than Copolymer A and the antifouling agent, such as a release regulator, a plasticizer, a pigment, a dye, an antifoaming agent, a dehydrating agent, a thixotropic agent, and an organic solvent, can be added to the resin for the antifouling coating material of the present invention to form an antifouling coating material.

[0048] Examples of the elution modifier include monocarboxylic acids and their salts, such as rosin, rosin derivatives, naphthenic acid, cycloalkenylcarboxylic acids, bicycloalkenylcarboxylic acids, versatic acid, trimethylisobutenylcyclohexenecarboxylic acid, and metal salts thereof, or alicyclic hydrocarbon resins. These can be used alone or in combination of two or more.

[0049] Of these, rosin, rosin derivatives, naphthenic acid, versatic acid, trimethylisobutenylcyclohexenecarboxylic acid, or metal salts thereof are preferred.

[0050] Examples of the rosin derivatives include hydrogenated rosin, disproportionated rosin, maleated rosin, formylated rosin, and polymerized rosin.

[0051] Examples of the plasticizer include paraffin-based plasticizers such as liquid paraffin and chlorinated paraffin; vegetable oil-based plasticizers such as linseed oil, epoxidized linseed oil, soybean oil, and epoxidized soybean oil; aromatic diester-based plasticizers such as di-n-octyl phthalate, di-2-ethylhexyl phthalate, isononyl phthalate, diisodecyl phthalate, diisononyl 2,5-furandicarboxylate, di-2-ethylhexyl isophthalate, and di-2-ethylhexyl terephthalate; aromatic triester-based plasticizers such as tributyl trimellitate and tri-2-ethylhexyl trimellitate; aromatic tetraester-based plasticizers such as tetra-2-ethylhexyl pyromellitate; di-2-ethylhexyl 4-cyclohexene-1,2-dicarboxylate; and 1,2-cyclohexanedicarboxylic acid. Alicyclic ester-based plasticizers such as diisononyl adipate and di-2-ethylhexyl 4,5-epoxycyclohexane-1,2-dicarboxylate; fatty acid ester-based plasticizers such as di-2-butoxyethyl adipate, diisononyl adipate and di-2-ethylhexyl azelate; (acetylated) hydroxycarboxylic acid ester-based plasticizers such as tributyl citrate, triethyl acetyl citrate, tributyl acetyl citrate and tri-2-ethylhexyl acetyl citrate; polyhydric alcohol ether / ester-based plasticizers such as diethylene glycol dibenzoate, dipropylene glycol dibenzoate, triethylene glycol di(2-ethylhexanoate), propylene glycol dilaurate, triacetin, tributyrin; Phosphate ester plasticizers such as trimethyl phosphate and tricresyl phosphate, Polyvinyl alkyl ether plasticizers such as Lutonal M40 and Lutonal A25, Polyester plasticizers, Camphor, terpene phenol, t-nonyl pentasulfide, etc. These can be used alone or in combination of two or more.

[0052] Among these, paraffin-based, vegetable oil-based, aliphatic ester-based, and aromatic ester-based solvents are preferred from the viewpoint of availability, and among these, chlorinated paraffin, liquid paraffin, epoxidized soybean oil, triethyl acetylcitrate, tributyl acetylcitrate, tri-2-ethylhexyl acetylcitrate, diisononyl phthalate, diisodecyl phthalate, diisononyl 1,2-cyclohexanedicarboxylate, di-2-ethylhexyl terephthalate, and tri-2-ethylhexyl trimellitate are more preferred, and chlorinated paraffin and liquid paraffin are preferred from the viewpoint of cost.

[0053] The content of the plasticizer in the composition of the present invention is not particularly limited, but is usually 0.01 to 30 mass% in terms of solid content, and from the viewpoints of paint viscosity and coating film hardness, it is preferably 0.05 to 25 mass%, more preferably 0.1 to 20 mass%.

[0054] Examples of copolymers and resin components other than Copolymer A include (meth)acrylic resins other than Copolymer A, polyester resins, vinyl resins, petroleum resins, metal-containing resins, zwitterionic compound-containing resins, silicone resins, and alicyclic hydrocarbon resins.

[0055] Examples of commercially available alicyclic hydrocarbon resins include Quinton 1500, 1525L, and 1700 (trade names, manufactured by Zeon Corporation).

[0056] Examples of the dehydrating agent include synthetic zeolite adsorbents, orthoesters, silicates such as tetramethoxysilane and tetraethoxysilane, isocyanates, carbodiimides, carbodiimidazoles, etc. These can be used alone or in combination of two or more.

[0057] 2. Method for producing antifouling coating composition The antifouling coating composition of the present invention can be produced, for example, by mixing and dispersing a mixture containing copolymer A and other additives using a disperser. The mixed liquid is preferably one in which various materials such as the copolymer and the antifouling agent are dissolved or dispersed in a solvent. As the dispersing machine, for example, a machine that can be used as a fine grinding machine can be suitably used. For example, a commercially available homomixer, sand mill, bead mill, etc. can be used. Alternatively, the mixed liquid may be mixed and dispersed using a container equipped with a stirrer and containing glass beads or the like for mixing and dispersion.

[0058] 3. Antifouling treatment method, antifouling coating film, and coated object The antifouling treatment method of the present invention uses the above antifouling coating composition to form an antifouling coating film on the surface of an object to be coated. According to the antifouling treatment method of the present invention, the antifouling coating film gradually dissolves from the surface, allowing the coating surface to be constantly renewed, thereby preventing the adhesion of aquatic fouling organisms. Examples of objects on which a coating film is formed include ships (particularly ship bottoms), fishing equipment, underwater structures, and the like. The thickness of the antifouling coating film may be appropriately set depending on the type of object to be coated, the sailing speed of the ship, the seawater temperature, etc. For example, when the object to be coated is the bottom of a ship, the thickness of the antifouling coating film is usually 50 to 700 μm, and preferably 100 to 600 μm. [Example]

[0059] The following examples will be given to further clarify the features of the present invention, but the present invention is not limited to these examples.

[0060] In each Production Example, Example, and Comparative Example, % represents % by mass. The viscosity is a value measured at 25°C using an E-type viscometer. The weight-average molecular weight (Mw) is a value (polystyrene equivalent) determined by GPC. The GPC conditions are as follows:

[0061] Equipment: Tosoh Corporation HLC-8320GPC Guard column: TSKgel SuperHZ-L Columns: TSKgel SuperHZM-M (2 columns) Flow rate...0.35 mL / min Detector: RI Column thermostatic bath temperature: 40°C Eluent...THF Standard material for creating calibration curve: Standard polystyrene (Agilent Technologies) Peak tops (Mp): 1,044,000, 728,000, 364,000, 206,000, 107,100, 46,380, 27,060, 12,980, 6,660, 2,790, 1,300, 1,140, ​​162 Calibration curve: A cubic equation was created based on the Mp values ​​and elution times of the above standard substances. Analysis software: EcoSEC Version 2.02, EcoSEC DaTa Analysis Version 1.14 Analysis conditions: In the obtained RI chromatogram, the flat, stable parts of the baseline immediately before and after the polymer elution were connected with straight lines to detect and analyze the polymer. However, if peaks of monomers remaining in the manufacturing process or impurities derived from monomers (oligomers, etc.) partially overlapped with the polymer peak, the chromatogram was vertically divided at the deepest point where these peaks overlapped with the polymer to separate the polymer from the monomer and impurity portions, and the molecular weight (Mw and Mn) and molecular weight distribution (Mw / Mn) of the polymer portion alone were calculated.

[0062] The heating residue is a value measured in accordance with JIS K 5601-1-2:1999 (ISO 3251:1993) "Paint component testing method - heating residue."

[0063] 1. Example of copolymer solution production Copolymer solutions A-1 to A-8 containing copolymer A and copolymer solutions B-1 to B-6 containing copolymers other than copolymer A were obtained according to the methods shown in Production Examples 1 to 8 and Comparative Production Examples 1 to 6. The heating residue, weight average molecular weight (Mw), molecular weight distribution (Mw / Mn), and viscosity of each of the obtained copolymer solutions were measured and are shown in Tables 1 to 3.

[0064] [Table 1]

[0065] [Table 2]

[0066] [Table 3]

[0067] <Production Example 1 (Production of Copolymer Solution A-1)> A flask equipped with a thermometer, a reflux condenser, a stirrer, and a dropping funnel was prepared. All of the raw material charging and polymerization reactions were carried out under a nitrogen atmosphere.

[0068] 300g of xylene was placed in a flask and 100g in a dropping funnel. In a separate container, 300g of triisopropylsilyl methacrylate, 105g of 2-methoxyethyl acrylate, 10g of 2-ethoxyethyl acrylate, 25g of 2-methoxyethyl methacrylate, 55g of methyl methacrylate, and 5g of 2-ethylhexyl acrylate were mixed to prepare a monomer mixture. Half of the monomer mixture was placed in the flask, and the other half was placed in the dropping funnel [monomer mixture ratio (initial flask charge / total amount) = 0.5].

[0069] Next, 0.3 g of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator was added to the flask, and 50 g of 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate (Perocta O, manufactured by Nippon Oil & Fats Co., Ltd.) was added to the dropping funnel, and the solutions in the flask and the dropping funnel were mixed thoroughly (the concentration of the polymerization initiator in the mixed solution in the flask was lower than the concentration of the polymerization initiator in the mixed solution in the dropping funnel).

[0070] The mixture in the flask was slowly heated and stirred at 85±5°C for 1 hour (first-stage polymerization reaction). Compared to the initial state immediately after the temperature reached 85°C, the viscosity of the solution in the flask after 1 hour of heating and stirring had increased.

[0071] Subsequently, while the mixture in the flask was kept at 85±5° C., the mixture in the dropping funnel was added dropwise to it over 1 hour, and then the mixture was stirred at the same temperature for 1 hour (second-stage polymerization reaction).

[0072] As the final step of the polymerization reaction, 1 g of 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate (Perocta O, manufactured by Nippon Oil & Fats Co., Ltd.) was added three times every hour to polymerize the trace amounts of remaining monomers, thereby completing the polymerization reaction.

[0073] The heating device was turned off and the mixture was allowed to cool to room temperature, after which 100 g of xylene was added and mixed to obtain a copolymer solution A-1.

[0074] <Production Examples 2 to 7 (Production of Copolymer Solutions A-2 to A-7)> Polymerization was carried out in the same manner as in Production Example 1 under the conditions of the monomer mixture ratio, reaction temperature, etc. shown in Tables 1 and 2, using the monomers, polymerization initiators, chain transfer agents, organic solvents, etc., in the amounts shown in the same tables, to obtain copolymer solutions A-2 to A-7. The chain transfer agent was mixed with various monomers in the amounts shown in the tables and used as part of the monomer mixture. The heating residue, weight average molecular weight (Mw), molecular weight distribution (Mw / Mn), and viscosity of each of the obtained copolymer solutions were measured and are listed in the tables.

[0075] <Production Example 8 (Production of Copolymer Solution A-8)> A flask equipped with a thermometer, a reflux condenser, a stirrer, and a dropping funnel was prepared. All of the raw material charging and polymerization reactions were carried out under a nitrogen atmosphere.

[0076] A monomer mixture consisting of the monomers shown in Production Example 8 in Table 2 was charged into a flask in its entirety [ratio of monomer mixture (initial amount charged into flask / total amount)=1.0].

[0077] Next, 300 g of xylene was placed in the flask. 5 g of 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate (Perocta O, manufactured by Nippon Oil & Fats Co., Ltd.) and 100 g of xylene were placed in the dropping funnel and mixed thoroughly (a total of 105 g of the mixed liquid was prepared in the dropping funnel).

[0078] The temperature of the mixture in the flask was slowly raised and stabilized at 85±5°C. The mixture in the dropping funnel was added in shots every hour in the order of 5g, 10g, 55g, and 35g to the solution in the flask, which was being stirred at 85±5°C, to advance the polymerization reaction (a process of adding an appropriate amount of the mixture in the dropping funnel all at once and then stirring for one hour was repeated, and including the one hour of stirring after the final 35g addition, a total of four hours was required).

[0079] Immediately after each shot addition, heat was generated, so the heating and cooling equipment was adjusted as needed to maintain a constant temperature of 85±5°C. After all shot additions of the mixed liquid in the dropping funnel were completed, the final step of the polymerization reaction was to polymerize the trace amounts of remaining monomer by adding 1 g of 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate (NOF Corporation; Perocta O) three times every hour to complete the polymerization reaction.

[0080] The heating device was turned off and the mixture was allowed to cool to room temperature, after which 100 g of xylene was added and mixed to obtain a copolymer solution A-8.

[0081] <Comparative Production Example 1 (Production of Copolymer Solution B-1)> A flask equipped with a thermometer, a reflux condenser, a stirrer, and a dropping funnel was prepared. All of the raw material charging and polymerization reactions were carried out under a nitrogen atmosphere.

[0082] 380 g of xylene was placed in a flask and heated to 85±5° C. 300 g of triisopropylsilyl methacrylate, 105 g of 2-methoxyethyl acrylate, 10 g of 2-ethoxyethyl acrylate, 25 g of 2-methoxyethyl methacrylate, 55 g of methyl methacrylate, 5 g of 2-ethylhexyl acrylate, 8 g of 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate (manufactured by NOF Corporation; Perocta O) as a polymerization initiator, and 30 g of xylene were placed in a dropping funnel and mixed.

[0083] Next, the mixture was added dropwise to the xylene in the flask over a period of 2 hours while the flask was being heated and mixed at 85±5°C (the polymerization reaction was carried out while the monomer mixture with a constant concentration of polymerization initiator was added dropwise at a constant rate). After that, the mixture was heated and stirred at the same temperature for 1 hour.

[0084] As the final step of the polymerization reaction, 1 g of 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate (NOF Corporation; Perocta O) was added three times every hour to polymerize the trace amounts of remaining monomers, and the polymerization reaction was completed. Then, 90 g of xylene was added and mixed to obtain copolymer solution B-1.

[0085] <Comparative Production Example 2 (Production of Copolymer Solution B-2)> Polymerization was carried out in the same manner as in Comparative Production Example 1 under the conditions such as reaction temperature shown in Table 2, using the monomers, polymerization initiators, organic solvents, etc., also shown in the same table, in the amounts shown therein, to obtain copolymer solution B-2.

[0086] <Comparative Production Examples 3 to 6 (Production of Copolymer Solutions B-3 to B-6)> Copolymer solutions B-3 to B-6 were obtained by polymerization in the same manner as in Production Example 1, using the monomers, polymerization initiators, chain transfer agents, organic solvents, etc., in the amounts shown in Table 3 under conditions such as the distribution ratio of the monomer mixture and reaction temperature shown in Table 3. The chain transfer agent was mixed with various monomers in the amount shown in Table 3 and used as part of the monomer mixture.

[0087] 2. Other manufacturing examples <Production Example 9 (Production of Rosin Zinc Salt Solution)> 240 g of Chinese gum rosin (WW) and 360 g of xylene were placed in a flask equipped with a thermometer, reflux condenser, and stirrer. 120 g of zinc oxide was then added so that all of the resin acid in the rosin would form zinc salts. The mixture was refluxed and dehydrated under reduced pressure at 70-80°C for 3 hours. The mixture was then cooled and filtered to obtain a xylene solution of rosin zinc salt (a dark brown, transparent liquid with a solid content of 50%). The residual content of the resulting solution was 50.4%.

[0088] <Production Example 10 (Production of trimethylisobutenylcyclohexenecarboxylic acid solution)> A flask equipped with a thermometer, reflux condenser, and stirrer was charged with 320 g of alloocimene, 175 g of methacrylic acid, and 0.17 g of MEHQ, and the mixture was heated and stirred at 35 to 45°C for 24 hours. Unreacted raw materials were then distilled off under reduced pressure to obtain 73 g of brown, viscous trimethylisobutenylcyclohexenecarboxylic acid. Xylene was added to this to obtain a trimethylisobutenylcyclohexenecarboxylic acid solution (solid content 50%).

[0089] 3. Examples 1 to 15 and Comparative Examples 1 to 6 (Production of Coating Compositions) The components shown in Tables 4 to 6 were blended in the proportions (mass %) shown in these tables, and mixed and dispersed with glass beads having a diameter of 1.5 to 2.5 mm to produce coating compositions.

[0090] [Table 4]

[0091] [Table 5]

[0092] [Table 6]

[0093] Details of each component in the table are as follows:

[0094] <Plasticizer> Chlorinated paraffin: Trade name "Paraffin Chlorinated (Cl: 40%)" (Wako Pure Chemical Industries, Ltd.) Liquid paraffin: Product name "Cosmo SP-32 Cosmo White P200" (Cosmo Oil Lubricants Co., Ltd.) E-2000H: Epoxidized soybean oil, product name "Sanso Cizer E-2000H" (manufactured by New Japan Chemical Co., Ltd.) Lutonal A25: Trade name "Lutonal (registered trademark) A25" (manufactured by BASF) JP120: Benzoic acid glycol ester, product name "JP120" (manufactured by J-Plus Co., Ltd.) DINP: Diisononyl phthalate: Trade name "Diisononyl phthalate" (manufactured by Wako Pure Chemical Industries, Ltd.) DINCH: Diisononyl 1,2-cyclohexanedicarboxylate: trade name "HEXAMOLL® DINCH®" (manufactured by BASF) DEHT: Di(2-ethylhexyl) terephthalate: Trade name "Bis(2-ethylhexyl) terephthalate" (manufactured by SIGMA-ALDRICH) TOTM: Tris(2-ethylhexyl) Trimellitate (trade name: "Tris(2-ethylhexyl) Trimellitate") (Tokyo Chemical Industry Co., Ltd.) ATBC: Tributyl acetyl citrate: Trade name "Tributyl O-Acetylcitrate" (Tokyo Chemical Industry Co., Ltd.)

[0095] <Anti-fouling agent> Cuprous oxide: Product name "NC-301" (manufactured by Nisshin Chemco Co., Ltd.) Copper rhodanide: Trade name "Copper(I) thiocyanate" (manufactured by SIGMA-ALDRICH) Copper pyrithione: Trade name "Copper Omadine" (Arch Chemical Co., Ltd.) Zinc pyrithione: Trade name "Zinc Omadin" (Arch Chemical Co., Ltd.) Zineb: Product name "Zineb" (manufactured by SIGMA-ALDRICH) SeaNine: Trade name "SeaNine 211" 4,5-dichloro-2-n-octyl-3(2H)isothiazoline (30% solids solution in xylene, manufactured by Rohm and Haas) Econia: Trade name "Econea 028" 2-(p-chlorophenyl)-3-cyano-4-bromo-5-trifluoromethylpyrrole (manufactured by Janssen PMP) Medetomidine: Trade name "4-(1-(2,3-Dimethylphenyl)ethyl)-1H-imidazole" (Wako Pure Chemical Industries, Ltd.)

[0096] <Dissolution modifier> Rosin zinc salt solution: Use the solution prepared in Production Example 9 Hydrogenated rosin solution: 50% solids solution of "Hypal CH" (manufactured by Arakawa Chemical Industries, Ltd.) in xylene Rosin solution: 50% solids xylene solution of Chinese gum rosin (WW) Tall rosin: Product name "Hartol R-WW" (Harima Chemicals Co., Ltd.) NT-RMZ: Hydrogenated rosin zinc salt solution: Product name "NT-RMZ" (manufactured by Nitto Kasei Co., Ltd.) was used. Solid content: 65%. Cyclohexenecarboxylic acid solution: trimethylisobutenylcyclohexenecarboxylic acid solution (used as prepared in Preparation Example 10)

[0097] <Other additives, solvents> Bengala: Product name "TODA COLOR EP-13D" (manufactured by Toda Pigment Co., Ltd.) Talc: Product name "Crown Talc 3S" (Matsumura Sangyo Co., Ltd.) Zinc oxide: Product name "Zinc Oxide 2" (Seido Chemical Co., Ltd.) Titanium oxide: Product name "FR-41" (manufactured by Furukawa Co., Ltd.) Tetraethoxysilane: Trade name "Tetraethyl Orthosilicate" (manufactured by Tokyo Chemical Industry Co., Ltd.) Anhydrous gypsum: Product name "D-1" (manufactured by Noritake Company Limited) Aliphatic amide thixotropic agent: Trade name "Disparlon A603-20X" (Kusumoto Chemicals Co., Ltd.) Denatured alcohol: Product name "Clean Ace High" (manufactured by Imazu Pharmaceutical Industries Co., Ltd.)

[0098] 4. Evaluation Using the coating compositions of the Examples and Comparative Examples, test panels (second test panels) having respective dried coating films were prepared through the following steps, and Test Examples 1 to 3 were carried out. The results are shown in Tables 4 to 6.

[0099] <Creating the second test panel> First, an anti-rust coating film was formed by applying an anti-rust paint (epoxy vinyl A / C) to a titanium plate (71 x 100 mm, thickness: 0.5 mm) to a thickness of approximately 100 μm after drying and drying. The coating compositions obtained in the Examples and Comparative Examples were then applied to the anti-rust coating film to a thickness of approximately 400 μm after drying. The test plate was dried at 40°C for 3 days to obtain a test plate (hereinafter referred to as the first test plate) having a dried coating film made of the coating composition obtained in the Examples and Comparative Examples.

[0100] The first test plate was fixed to the rotating drum described below so that it was in contact with seawater, and the rotating drum was rotated at a speed of 20 knots. During this time, the seawater temperature was maintained at 25°C, the pH at 8.0 to 8.2, and the seawater was replaced every week.

[0101] The first test plate, which had been attached to a rotating drum and rotated in contact with seawater for 24 months, was removed, and the seawater adhering to the coating surface was lightly rinsed off with pure water, and then dried for 3 days at 40° C. A paint having the same composition as the paint composition used to prepare the first test plate was applied to the coating surface remaining on this test plate so that the thickness after drying would be approximately 300 μm.

[0102] This test plate was dried at 40°C for 3 days to obtain a test plate (second test plate) having a new dried coating film.

[0103] <Details of the rotating drum device> The rotating drum is a motor-driven drum (515mm diameter, 440mm high) mounted in the center of a water tank, and is equipped with a cooling device to maintain a constant seawater temperature and an automatic pH controller to maintain a constant seawater pH.A test plate can be placed on the rotating drum, and by rotating the paint film applied to the test plate at a constant speed while coming into contact with seawater, the device can simulate the behavior of a paint film applied to the bottom of a ship when operating at sea.

[0104] <Test Example 1 (Measurement of the amount of paint film dissolved after recoating)> The thickness of a second test panel having a coating made from the coating composition described in each Example or Comparative Example was measured using a laser focus displacement meter, and the panel was then fixed to a rotating drum device, which was then rotated at a speed of 20 knots. During this time, the seawater temperature was maintained at 25°C, the pH at 8.0-8.2, and the seawater was replaced every week.

[0105] After the start of the test, the test plate was removed from the rotating drum every six months, and the remaining film thickness was measured each time using a laser focus displacement meter.

[0106] For the coating compositions described in each Example and Comparative Example, the average amount dissolved per month (μm / month) for each period was calculated from the difference in coating thickness between the initial coating thickness and every six months after the start of the test.

[0107] The samples were classified according to the following criteria, and the stability of their dissolution behavior was evaluated. A: Average dissolution amount per month (μm / month) is 5 or more and less than 15 B: Average dissolution amount per month (μm / month) is 2 or more and less than 5 C: Average dissolution amount per month (μm / month) is 15 or more ×: Average dissolution amount per month (μm / month) is less than 2 -: All coatings on the subject dissolved or peeled off within 6 months.

[0108] <Test Example 2 (Paint Film Property Verification Test)> After the 24-month dissolution test in Test Example 1, the test plates were dried and the surfaces of the coating films were visually observed to evaluate the state of the coating films. The evaluation was carried out by the following method.

[0109] ◎: No abnormalities at all ○: Hair cracks are observed on less than 10% of the total coating surface area △: Hair cracks are observed on 10-30% of the total coating surface area. ×: Hair cracks are observed on more than 30% of the total surface area of ​​the coating film. ××: Abnormalities in the coating such as large cracks, blisters, peeling (only the surface or part of the edge of the coating is peeled off), or delamination (the entire coating is peeled off and no test coating remains)

[0110] <Test Example 3 (Adhesion)> After the 24-month dissolution test in Test Example 1, the test panels were dried and the coating adhesion was measured using a cross-cut test according to JIS K5600-5-6. Using a utility knife, 6x6 cuts spaced 3 mm apart were made in the test piece. After the tape was removed from the test piece, the remaining cross-cut areas were visually inspected and evaluated according to the following criteria. Regarding peeling criteria, peeling of individual layers was not classified; peeling from the undercoat anticorrosive paint, peeling from the old antifouling coating, and partial peeling of the overcoat were all considered together. The state of the coating adhering to the tape and peeling from the test panel was evaluated according to the following criteria.

[0111] ◎: No peeling in any of the grids. ◯: There is small peeling of the coating at the intersection of the cuts, but the peeling does not clearly exceed 5% of the area of ​​the test section. △: The coating film peeled off at the intersection along the cut line, and the peeling was 5% or more and less than 35% of the area of ​​the test part. ×: The coating film is partially or entirely peeled off along the edge of the cut, and the peeling accounts for 35% or more of the area of ​​the test part. -: If peeling of 35% or more of the test area has occurred immediately before the cross-cut test.

[0112] <Test Results> In Test Examples 1 to 3, a paint of the same composition was applied to an old paint film whose surface had been polished in seawater for 24 months, and the various performance characteristics of the resulting dried paint film were evaluated. This simulates the evaluation of the paint film performance after repainting an antifouling paint for an actual ship's bottom during repairs.

[0113] Test Example 1 shows that the antifouling coating composition described in this example has good and stable long-term coating film solubility for 24 months after recoating, with no change in dissolution behavior (Examples in Tables 4 and 6).

[0114] In Test Example 2, the antifouling coating composition described in this example did not develop coating film abnormalities such as cracks or blisters for 24 months after recoating, confirming the high physical properties of the coating film (Examples in Tables 4 and 6).

[0115] Furthermore, Test Example 3 directly demonstrates that the antifouling coating composition described in this example can be recoated with a coating of the same composition even after it has been polished in seawater for a certain period of time and the surface properties have changed, and that the adhesion is high (Tables 4 and 6).

[0116] These results clearly demonstrate that the high coating film performance (coating film solubility, coating film physical properties, adhesion) after recoating on an old coating film, which is a feature of the present invention, is achieved by containing Copolymer A, which has a specific composition and a specific molecular weight distribution (Mw / Mn) (Examples in Table 4 and Comparative Examples in Table 5).

[0117] Furthermore, it was found that, within the scope of the present invention, if an appropriate amount of copolymer A is contained, this effect can be achieved even if the amount or type of antifouling agent, pigment component, solute adjuster component, etc. is changed (Table 6).

Claims

1. A copolymer for an antifouling coating composition obtained by copolymerizing a monomer mixture composed of a monomer (a), a monomer (b), and a monomer (c), The monomer (a) is represented by general formula (1): The monomer (b) is represented by general formula (2): the monomer (c) is a monomer other than the monomer (a) and the monomer (b) that is copolymerizable with the monomer (a) and the monomer (b), the monomer (c) is selected from a (meth)acrylic acid ester, a vinyl compound, an aromatic compound, a dibasic acid dialkyl ester compound, an unsaturated monocarboxylic acid compound, a compound having a zwitterionic structure, and a triorganosilyl (meth)acrylate other than the monomer (a); the (meth)acrylic acid ester is selected from methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, zinc (meth)acrylate, copper (meth)acrylate, zinc (meth)acrylate versatate, copper (meth)acrylate versatate, zinc (meth)acrylate naphthenate, copper (meth)acrylate naphthenate, zinc (meth)acrylate stearate, and copper (meth)acrylate abietic acid; the proportion of the monomer (a) in the monomer mixture is 25 to 60 mass %, The copolymer has a molecular weight distribution (Mw / Mn) of 5.0 or more, The copolymer is a copolymer for an antifouling coating composition that does not contain sulfur atoms. 【Chemistry 1】 (In the formula, R １ is hydrogen or a methyl group, and R ２ ~R ４ are the same or different and each represents a branched alkyl group having 3 to 8 carbon atoms or a phenyl group. 【Chemistry 2】 (In the formula, R ５ is hydrogen or a methyl group, and R 6 is a hydrocarbon group having 2 to 9 carbon atoms and an oxygen atom.

2. The copolymer for an antifouling coating composition according to claim 1, A copolymer for an antifouling coating composition, having a Mw of 5,000 to 30,000.

3. An antifouling coating composition comprising a copolymer for an antifouling coating composition and an antifouling agent, An antifouling coating composition, wherein the copolymer for the antifouling coating composition is the copolymer according to claim 1 or 2.

Images