Antifouling coating composition

Abstract

Provided is an antifouling coating composition which can maintain a stable coating film dissolution rate in low-temperature seawater for a long period of time and can maintain stable antifouling performance. The present invention provides an antifouling coating composition containing a copolymer A and an antifouling agent D. The copolymer A is a copolymer of a monomer (a) represented by general formula (1) and an ethylenically unsaturated monomer (b) other than the monomer (a), and the monomer (a) contains a compound in which n in general formula (1) is 2 or more. The monomer (b) contains a monomer (b1) represented by general formula (2), and the ratio of the monomer (b1) to the total of the monomer (a) and the monomer (b) is 0.01-2 mol%.

Description

Technical Field

[0001] The present invention relates to an antifouling coating composition. Background Art

[0002] Aquatic fouling organisms such as barnacles, tube worms, mussels, bryozoans, ascidians, sea mosses, Ulva, and mucus can attach to ships (especially the bottoms), fishing nets, fishing net accessories, and other fishing gear, as well as underwater structures such as power plant aqueducts. These can cause functional damage and cosmetic problems on ships and other structures. To prevent these 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 the antifouling agent is gradually released from the antifouling coating film to exhibit antifouling performance for a long period of time (Patent Documents 1 to 4).

[0003] However, the antifouling coatings composed of polymers containing alkoxycarbonylmethyl (meth)acrylate groups described in Patent Documents 1 to 4 have extremely low solubility, making it difficult to exert long-term antifouling performance. To address these issues, a technology has been proposed that can dissolve the coating and exert antifouling performance over a long period of time (Patent Document 5). Furthermore, a technology has also been proposed that improves the physical properties of the coating, such as cracking and peeling (Patent Document 6).

Prior art literature

[0004] [Patent Document 1] Japanese Showa Patent No. 63-61989 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-119420 [Patent Document 3] Japanese Patent Application Laid-Open No. 2003-119419 [Patent Document 4] Japanese Patent Application Laid-Open No. 2002-3776 [Patent Document 5] WO2020 / 045211 [Patent Document 6] WO2022 / 102492 Summary of the Invention [Problems to be solved by the invention]

[0005] Although the antifouling coating films formed from the antifouling coating compositions described in Patent Documents 5 and 6 have improved solubility and physical properties, their solubility in low-temperature seawater below 15°C still needs to be improved. Therefore, the industry has known that it is desirable to develop an antifouling coating composition that can maintain excellent antifouling performance for a long time even in low-temperature seawater.

[0006] In view of the above situation, the present invention aims to provide an antifouling coating composition that can maintain a stable paint film dissolution rate in low-temperature seawater for a long time and maintain stable antifouling performance. [Technical solutions to solve problems]

[0007] According to the present invention, there is provided an antifouling coating composition comprising a copolymer A and an antifouling agent D, wherein the copolymer A is a copolymer of a monomer (a) represented by the general formula (1) and an ethylenically unsaturated monomer (b) other than the monomer (a), the monomer (a) comprises a compound wherein n in the general formula (1) is 2 or greater, and the monomer (b) comprises a monomer (b1) represented by the general formula (2), wherein the proportion of the monomer (b1) is 0.01 to 2 mol % relative to the total of the monomer (a) and the monomer (b).

[0008] The present inventors have conducted intensive studies based on the above-mentioned problems and have found that a composition containing copolymer A and antifouling agent D can solve the above-mentioned problems, thereby completing the present invention. DETAILED DESCRIPTION

[0009] Hereinafter, the present invention will be described in detail. In this specification, (meth)acrylate means acrylate or methacrylate, and (meth)acrylic acid means acrylic acid or methacrylic acid. 1. Antifouling coating composition The antifouling coating composition of the present invention contains a copolymer A and an antifouling agent D.

[0010] 1-1. Copolymer A Copolymer A is a copolymer of monomer (a) and an ethylenically unsaturated monomer (b) other than monomer (a).

[0011] The content of monomer (a) relative to the total of monomer (a) and monomer (b) is preferably 10 to 90% by mass, more preferably 20 to 70% by mass. Specific examples include 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, and 90% by mass. The content may also be within a range between any two of the values exemplified here. In this case, the coating film solubility is particularly good.

[0012] The content of the monomer (b1) is 0.01 to 2 mol% of the total molar mass of the monomer (a) and the monomer (b), more preferably 0.1 to 1 mol%. Specific examples include 0.01, 0.05, 0.1, 0.5, 1.0, 1.5, and 2.0 mol%, and may be within a range between any two of the values exemplified here.

[0013] 1-1-1. Monomer (a) The monomer (a) is represented by the general formula (1).

[0014]

Chemical 1

[0015] R 2 is preferably hydrogen or methyl.

[0016] R 3 The alkyl group having 1 to 8 carbon atoms of R 3 can be substituted with a substituent or can be unsubstituted. The substituent can be an alkoxy group having 1 to 8 carbon atoms or phenyl. The number of carbon atoms of the alkoxy group or alkyl group of R 3 is, for example, 1, 2, 3, 4, 5, 6, 7, 8, or can be within the range between any two values exemplified herein. The alkyl group of R

[0017] is, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, 2-ethylhexyl, cyclohexyl, benzyl, phenyl, 2-methoxyethyl, 4-methoxybutyl, vinyl, allyl, and is preferably methyl, ethyl, isopropyl, n-butyl.

[0018] The monomer (a) contains a compound in which n in the general formula (1) is 2 or more. If the monomer (a) contains a compound in which n is 2 or more, the solubility of the coating film will be improved. The monomer (a) can consist only of a compound in which n is 2 or more, or can be a mixture of a compound in which n is 1 and a compound in which n is 2 or more.

[0019] The monomer (a) is preferably composed of the monomer (a1) and the monomer (a2). The content of the monomer (a1) in the monomer (a) is preferably 50 to 80% by mass, more preferably 55 to 75% by mass, and particularly preferably 60 to 70% by mass. The monomer (a1) has the property of being able to improve the coating film strength more than the monomer (a2) and reducing the solubility of the coating film. Therefore, if the content of the monomer (a1) is too low, there is a tendency for the coating film strength to decrease, and after long-term use, the surface state of the coating film may be more likely to deteriorate. On the other hand, if the content of the monomer (a1) is too high, the solubility of the coating film will decrease, which may lead to a decrease in the antifouling performance.

[0020] <Monomer (a1)> The monomer (a1) is a compound of the general formula (1) wherein n is 1. Examples of the monomer (a1) include methoxycarbonylmethyl (meth)acrylate, ethoxycarbonylmethyl (meth)acrylate, isopropoxycarbonylmethyl (meth)acrylate, n-propoxycarbonylmethyl (meth)acrylate, n-butoxycarbonylmethyl (meth)acrylate, tert-butoxycarbonylmethyl (meth)acrylate, 2-ethylhexyloxycarbonylmethyl (meth)acrylate, cyclohexyloxycarbonylmethyl (meth)acrylate, benzyloxycarbonylmethyl (meth)acrylate, phenoxycarbonylmethyl (meth)acrylate, 2-methoxyethoxycarbonylmethyl (meth)acrylate, 4-methoxybutoxycarbonylmethyl (meth)acrylate, allyloxycarbonylmethyl (meth)acrylate, vinyloxycarbonylmethyl (meth)acrylate, 1-(methoxycarbonyl)methyl (meth)acrylate, Preferably, the esters are methoxycarbonyl (meth)acrylate, 1-(ethoxycarbonyl)ethyl (meth)acrylate, 1-(n-propoxycarbonyl)ethyl (meth)acrylate, 1-(isopropoxycarbonyl)ethyl (meth)acrylate, 1-(n-butoxycarbonyl)ethyl (meth)acrylate, 1-(tert-butoxycarbonyl)ethyl (meth)acrylate, α-(methoxycarbonyl)benzyl (meth)acrylate, α-(ethoxycarbonyl)benzyl (meth)acrylate, and preferably methoxycarbonylmethyl (meth)acrylate, isopropoxycarbonylmethyl (meth)acrylate, isopropoxycarbonylmethyl (meth)acrylate, n-propoxycarbonylmethyl (meth)acrylate, n-butoxycarbonylmethyl (meth)acrylate, 1-(methoxycarbonyl)ethyl (meth)acrylate, and 1-(ethoxycarbonyl)ethyl (meth)acrylate.

[0021] <Monomer (a2)> The monomer (a2) is a compound wherein n in the general formula (1) is 2 or greater. From the viewpoint of long-term antifouling properties, n in the general formula (1) is preferably 2 to 6.

[0022] As monomer (a2), it is preferred to contain both a compound in which n is 2 and a compound in which n is 3 or greater. Specifically, for example, the mass ratio (n(2) / n(2-10)) is preferably 0.4-0.8, more preferably 0.5-0.7, based on solid content. In this case, a trend of stable coating film dissolution continuing is observed. This value can be, for example, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, or 0.80, or can be within the range between any two of the values exemplified here.

[0023] Examples of the monomer (a2) include (methyl)methyl di(oxycarbonylmethyl)acrylate, (methyl)ethyl di(oxycarbonylmethyl)acrylate, (methyl)isopropyl di(oxycarbonylmethyl)acrylate, (methyl)n-propyl di(oxycarbonylmethyl)acrylate, (methyl)n-butyl di(oxycarbonylmethyl)acrylate, (methyl)t-butyl di(oxycarbonylmethyl)acrylate, (methyl)2-ethylhexyl di(oxycarbonylmethyl)acrylate, (methyl)cyclohexyl di(oxycarbonylmethyl)acrylate, (methyl)benzyl di(oxycarbonylmethyl)acrylate, (methyl)phenyl di(oxycarbonylmethyl)acrylate, (methyl)2-methoxyethyl di(oxycarbonylmethyl)acrylate, (methyl)4-methoxybutyl di(oxycarbonylmethyl)acrylate, and the like. di(oxycarbonylmeth)acrylate, (meth)allyl di(oxycarbonylmeth)acrylate, (meth)vinyl di(oxycarbonylmeth)acrylate, (meth)methyl di[1-(oxypolycarbonyl)ethyl]acrylate, (meth)ethyl di[1-(oxypolycarbonyl)ethyl]acrylate, (meth)n-propyl di[1-(oxypolycarbonyl)ethyl]acrylate, (meth)isopropyl di[1-(oxypolycarbonyl)ethyl]acrylate, (meth)n-butyl di[1-(oxypolycarbonyl)ethyl]acrylate, (meth)tert-butyl di[1-(oxypolycarbonyl)ethyl]acrylate, (meth)methyl di[α-(oxycarbonyl)benzyl]acrylate, (meth)ethyl di[α-(oxycarbonyl)benzyl]acrylate,Preferred are (meth)methyl di(oxycarbonylmeth)acrylate, (meth)ethyl di(oxycarbonylmeth)acrylate, (meth)isopropyl di(oxycarbonylmeth)acrylate, (meth)n-propyl di(oxycarbonylmeth)acrylate, (meth)n-butyl di(oxycarbonylmeth)acrylate, (meth)methyl di[1-(oxypolycarbonylethyl)]acrylate, (meth)ethyl di[1-(oxypolycarbonylethyl)]acrylate, (meth)methyl poly(oxycarbonylmeth)acrylate, (meth)ethyl poly(oxycarbonylmeth)acrylate, (meth)isopropyl poly (oxycarbonyl meth)acrylate, (meth)n-propyl poly(oxycarbonyl meth)acrylate, (meth)n-butyl poly(oxycarbonyl meth)acrylate, (meth)t-butyl poly(oxycarbonyl meth)acrylate, (meth)2-ethylhexyl poly(oxycarbonyl meth)acrylate, (meth)cyclohexyl poly(oxycarbonyl meth)acrylate, (meth)benzyl poly(oxycarbonyl meth)acrylate, (meth)phenyl poly(oxycarbonyl meth)acrylate, (meth)2-methoxyethyl poly(oxycarbonyl meth)acrylate, (meth)4-methoxybutyl poly(oxycarbonyl meth)acrylate ) acrylate, (meth)allyl poly(oxycarbonylmeth)acrylate, (meth)vinyl poly(oxycarbonylmeth)acrylate, (meth)methyl poly[1-(oxypolycarbonyl)ethyl]acrylate, (meth)ethyl poly[1-(oxypolycarbonyl)ethyl]acrylate, (meth)n-propyl poly[1-(oxypolycarbonyl)ethyl]acrylate, (meth)isopropyl poly[1-(oxypolycarbonyl)ethyl]acrylate, (meth)n-butyl poly[1-(oxypolycarbonyl)ethyl]acrylate, (meth)t-butyl poly[1-(oxypolycarbonyl)ethyl]acrylate, ( (methyl)methyl poly[α-(oxycarbonyl)benzyl]acrylate, (methyl)ethyl poly[α-(oxycarbonyl)benzyl]acrylate, preferably (methyl)methyl poly(oxycarbonylmeth)acrylate, (methyl)ethyl poly(oxycarbonylmeth)acrylate, (methyl)isopropyl poly(oxycarbonylmeth)acrylate, (methyl)n-propyl poly(oxycarbonylmeth)acrylate, (methyl)n-butyl poly(oxycarbonylmeth)acrylate, (methyl)methyl poly[1-(oxypolycarbonylethyl)]acrylate, (methyl)ethyl poly[1-(oxypolycarbonylethyl)]acrylate, etc.

[0024] 1-1-2. Monomer (b) Monomer (b) is an ethylenically unsaturated monomer other than monomer (a). Monomer (b) can be classified into monomer (b1) and monomer (b2). Monomer (b) used for polymerization of copolymer A contains at least monomer (b1).

[0025] The ratio of the monomer (b1) to the total of the monomer (a) and the monomer (b) is 0.01 to 2 mol%, preferably 0.1 to 1.5 mol%. Specific examples of this ratio include 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.5, and 2.0 mol%, and may be within a range between any two of the values exemplified here.

[0026] <Monomer (b1)> The monomer (b1) is one or two or more compounds selected from the compounds represented by the general formula (2).

Chemistry 2

[0027] R 4 Preferably, it is hydrogen. m is preferably 0 or 1, more preferably 0. Specifically, m is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10, and may be within the range between any two of the values exemplified here.

[0028] Examples of the monomer (b1) include (meth)acrylic acid and hydroxycarbonylmethyl (meth)acrylate.

[0029] <Monomer (b2)> Monomer (b2) is obtained by removing monomer (b1) from monomer (b). In other words, monomer (b2) is a monomer that cannot be represented by any of the general formulas (1) to (2). Examples of monomer (b2) include (meth)acrylates, vinyl compounds, aromatic compounds, and dialkyl esters of dibasic acids that cannot be represented by the general formulas (1) to (2).

[0030] Examples of the (meth)acrylate monomer (b2) include (meth)acrylates such as methyl methacrylate, methyl acrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, n-butyl acrylate, n-butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, lauryl acrylate, lauryl methacrylate, benzyl acrylate, benzyl methacrylate, phenyl acrylate, and cyclic trimethylolpropane acrylate. Examples thereof include (meth)acrylic acid alkyl esters such as triisopropylsilyl acrylate and triisopropylsilyl methacrylate.

[0031] Examples of the vinyl compound monomer (b2) include vinyl compounds having a functional group such as vinyl chloride, vinylidene chloride, vinyl benzoate, vinyl butyrate, butyl vinyl ether, and lauryl vinyl ether.

[0032] Examples of the aromatic compound monomer (b2) include styrene, vinyltoluene, and α-methylstyrene.

[0033] Examples of the monomer (b2) which is a dialkyl ester compound of a dibasic acid include dibutyl maleate and the like.

[0034] 1-1-3. Physical Properties and Production Method of Copolymer A The weight-average molecular weight (Mw) of copolymer A is preferably between 5,000 and 300,000. If the molecular weight is less than 5,000, the antifouling coating film becomes fragile and prone to flaking and cracking. If the molecular weight exceeds 300,000, the viscosity of the polymer solution increases, making handling difficult. Specific examples of the Mw include 5,000, 10,000, 20,000, 30,000, 40,000, 50,000, 60,000, 70,000, 80,000, 90,000, 100,000, 200,000, and 300,000. The Mw may also be within a range between any two of the values exemplified herein.

[0035] As a method for measuring Mw, gel permeation chromatography (GPC method) can be mentioned.

[0036] Copolymer A may be any of a random copolymer, an alternating copolymer, a periodic copolymer or a block copolymer of monomer (a1), monomer (a2), monomer (b1) and monomer (b2).

[0037] For example, the copolymer A can be obtained by polymerizing the monomer (a1), the monomer (a2), the monomer (b1), and the monomer (b2) in the presence of a polymerization initiator.

[0038] Examples of the polymerization initiator include azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2'-azobisisobutyrate, dimethyl 2,2'-azobisisobutyrate, and 2,2'-azobis(N-butyl-2-methylpropionamide); benzoyl peroxide, di-tert-butyl peroxide, tert-butyl peroxybenzoate, and peroxide. Peroxides such as tert-butyl isopropyl carbonate, tert-butyl peroxy-2-ethylhexanoate, tert-hexyl peroxy-2-ethylhexanoate, di-tert-hexyl peroxide, tert-butyl peroxy-2-ethylhexyl carbonate, di-tert-butyl peroxide, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, tert-amyl peroxyneodecanoate, tert-hexyl peroxypivalate, tert-amyl peroxypivalate, and 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate are preferred. These polymerization initiators can be used alone or in combination of two or more. Preferred polymerization initiators include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2'-azobisisobutyrate, and 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate. The molecular weight of copolymer A can be adjusted by appropriately setting the amount of polymerization initiator used. Furthermore, a chain transfer agent can be used to adjust the molecular weight of the resulting polymer. Examples of chain transfer agents include mercaptans such as n-dodecylmercaptan; thioglycolates such as octyl thioglycolate; α-methylstyrene dimer; and terpinolene.

[0039] Examples of the polymerization method include solution polymerization, bulk polymerization, emulsion polymerization, suspension polymerization, and non-aqueous dispersion polymerization. Of these, solution polymerization and non-aqueous dispersion polymerization are particularly preferred because they can obtain the copolymer A simply and accurately.

[0040] In the polymerization reaction, an organic solvent may be used as needed. The organic solvent is not particularly limited, but examples thereof include aromatic hydrocarbon solvents such as xylene and toluene; aliphatic hydrocarbon solvents; ester solvents such as ethyl acetate, butyl acetate, isobutyl acetate, methoxypropanol acetate, and propylene glycol 1-monomethyl ether 2-acetate; alcohol solvents such as isopropyl alcohol, butanol, and propylene glycol monomethyl ether; ether solvents such as dioxane, diethyl ether, and butyl ether; and ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone. Among them, butyl acetate, isobutyl acetate, butanol, propylene glycol monomethyl ether, propylene glycol 1-monomethyl ether 2-acetate, toluene, and xylene are preferred. These solvents can be used alone or in combination of two or more. The reaction temperature in the polymerization reaction can be appropriately set depending on the type of the polymerization initiator and the like, and is usually 50 to 160°C, preferably 60 to 150°C.

[0041] The polymerization reaction is preferably carried out under an inert gas atmosphere such as nitrogen or argon.

[0042] 1-2. Antifouling agent D Examples of the antifouling agent D include inorganic agents and organic agents. Examples of inorganic agents include cuprous oxide, copper thiocyanate (common name: rhodamine copper), and copper powder. Cuprous oxide and rhodamine copper are particularly preferred. For long-term storage stability, cuprous oxide surface-treated with glycerol, sucrose, stearic acid, lauric acid, lecithin, or mineral oil is preferred.

[0043] Examples of organic agents include copper 2-pyridinethione-N-oxide (common name: copper pyrithione), zinc 2-pyridinethione-N-oxide (common name: zinc pyrithione), zinc ethylenedithiocarbamate (common name: mancozeb), 4,5-dichloro-2-n-octyl-3-isothiazolinone (common name: SEA-NINE 211), 3,4-dichlorophenyl-NN-dimethylurea (common name: diuron), 2-methylthio-4-tert-butylamino-6-cyclopropylamino-s-triazine (common name: Irgarol 1051), 2-(p-chlorophenyl)-3-cyano-4-bromo-5-trifluoromethylpyrrole (common name: Econea 28), and 4-[1-(2,3-dimethylphenyl)ethyl]-1H-imidazole (common name: medetomidine). These antifouling agents may be used alone or in combination of two or more.

[0044] The content of the antifouling agent D in the composition of the present invention is not particularly limited, but is generally 0.1 to 60.0% by mass based on solid content. Examples of the content of the antifouling agent D include 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, and 60% by mass, and may also be within a range between any two of the values exemplified herein.

[0045] 1-3. Other additives Furthermore, the antifouling coating resin of the present invention may be added with resin components other than the copolymer A, dissolution regulators, plasticizers, pigments, dyes, defoamers, dehydrating agents, thixotropic agents, organic solvents, etc., as needed to prepare an antifouling coating.

[0046] Examples of dissolution modifiers include rosin, rosin derivatives, cycloalkanoic acid, cycloalkenyl carboxylic acid, bicycloalkenyl carboxylic acid, versatile carbonic acid, trimethylisobutenylcyclohexanecarboxylic acid, and metal salts thereof, monocarboxylic acids and salts thereof, and the aforementioned alicyclic hydrocarbon resins. These can be used alone or in combination of two or more. Examples of the rosin derivatives include hydrogenated rosin, disproportionated rosin, maleated rosin, formylated rosin, and polymerized rosin. Examples of commercially available products of the alicyclic hydrocarbon resin include Quintone 1500, 1525L, and 1700 (trade names, manufactured by ZEON Corporation of Japan). Among them, rosin, rosin derivatives, cyclohexanecarboxylic acid, versatile carbonic acid, trimethylisobutenylcyclohexanecarboxylic acid, and metal salts thereof are preferred.

[0047] Examples of the dehydrating agent include calcium sulfate, synthetic zeolite adsorbents, orthoesters, silicates such as tetramethoxysilane and tetraethoxysilane, isocyanates, carbodiimides, and carbondiimidazoles, etc. These can be used alone or in combination of two or more.

[0048] 2. Method for producing antifouling coating composition The antifouling coating composition of the present invention is prepared by, for example, mixing and dispersing a mixed solution containing the copolymer A, the antifouling agent D, and other additives using a disperser. The mixed liquid is preferably obtained by dissolving and dispersing various materials such as the copolymer A and the antifouling agent D in a solvent. As the disperser, it is preferable to use a device that can be used as a fine pulverizer, for example. For example, a commercially available homogenizer, sand mill, bead mill, disperser, etc. can be used. Alternatively, a container equipped with a stirrer and containing glass beads for mixing and dispersing can be used to mix and disperse the mixed liquid.

[0049] 3. Antifouling treatment methods, antifouling coatings, and coated materials The antifouling treatment method of the present invention utilizes the antifouling coating composition to form an antifouling coating on the surface of an object to be coated. The antifouling treatment method of the present invention prevents the attachment of aquatic fouling organisms by gradually dissolving the antifouling coating from the surface and continuously renewing the coating surface. Examples of the object to be coated include ships (particularly ship bottoms), fishing gear, and underwater structures. The thickness of the antifouling coating can be appropriately set depending on the type of the object to be coated, the navigation 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 is generally 50 to 700 μm, preferably 100 to 600 μm. [Example]

[0050] The features of the present invention will be further illustrated below by examples etc. However, the present invention is not limited to these examples. The weight average molecular weight (Mw) is a value determined by GPC (polystyrene equivalent value). The GPC conditions are as follows. Device…HLC-8220GPC manufactured by TOSOH Co., Ltd. Chromatography columns…TSKgel SuperHZM-M 2 pieces Flow rate…0.35mL / min Detector…RI Column thermostat temperature…40℃ Eluent…THF The heating residue is a value measured in accordance with JIS K 5601-1-2: 1999 (ISO 3251: 1993) "Testing methods for coating components - Heating residue".

[0051] 1. Manufacturing Example 1-1. Production Example of Monomer (a1) <Production Example 1 (Production of Monomer a1-1)> Methyl chloroacetate: 109g (1.00mol), acrylic acid: 72g (1.00mol), 4-methoxyphenol: 0.1g, ethyl acetate: 500g were added to a four-necked flask equipped with a thermometer, cooler, stirring device and dropping funnel. While stirring, triethylamine: 101g (1.00mol) was added dropwise to the flask while maintaining the temperature below 40°C. After the dropwise addition was completed, the mixture was stirred at 70-80°C for 6 hours. After the reaction was completed, the organic layer was washed with tap water, hydrochloric acid water, and soda water in sequence, and the solvent was removed by vacuum concentration to obtain monomer a1-1: 129.7g. <Production Examples 2 to 3 (Production of Monomers a1-2 to a1-3)> Using the raw materials shown in Table 1, monomers a1-2 to a1-3 were obtained by reaction in the same manner as in Production Example 1. The reaction conditions and yields of Production Examples 1 to 3 are shown in Table 1.

[0052]

Table 1

[0053] 1-2. Production Example of Monomer (a2) <Production Example 4 (Production of Monomer a2-1)> (1st reaction) 215 g (1.85 mol) of sodium chloroacetate, 201 g (1.85 mol) of methyl chloroacetate, and 300 g of N-methylpyrrolidone were added to a four-necked flask equipped with a thermometer, a cooler, and a stirrer, and stirred at 70-80°C for 6 hours. After the reaction, 500 ml of toluene was added to the reaction solution, and the organic layer was washed sequentially with tap water, hydrochloric acid solution, and soda water. The solvent was then removed by concentration under reduced pressure to obtain 262 g of methoxycarbonylmethyl chloroacetate.

[0054] (Second reaction) Next, 200 g (1.20 mol) of methoxycarbonylmethyl chloroacetate, the product of the first reaction, 87 g (1.20 mol) of acrylic acid, 0.1 g of 4-methoxyphenol, and 500 g of ethyl acetate were added to a four-necked flask equipped with a thermometer, a cooler, a stirrer, and a dropping funnel. 122 g (1.20 mol) of triethylamine was added dropwise while stirring, maintaining the temperature below 40°C. After the addition was complete, the mixture was stirred at 70-80°C for 6 hours. After the reaction was completed, the organic layer was washed sequentially with tap water, hydrochloric acid solution, and soda water, and then the solvent was removed by concentration under reduced pressure to obtain 230.6 g of monomer a2-1.

[0055] <Production Examples 5 to 18 (Production of Monomers a2-2 to a2-15)> Using the raw materials shown in Table 2, the same reaction procedures as in Preparation Example 4 were followed to obtain monomers a2-2 to a2-15 as shown in Table 2. The reaction conditions and yields of Preparation Examples 4 to 18 are shown in Table 2.

[0056]

Table 2

[0057] Details of the raw materials in Tables 1 and 2 are as follows. CAMe: Methyl chloroacetate CAEt: methyl chloroacetate AA: Acrylic acid MAA: Methacrylic acid TEA:Triethylamine MEHQ:4-Methoxyphenol CANa: Sodium chloroacetate NMP: N-methyl-2-pyrrolidone

[0058] 1-3. Example of Preparation of Copolymer Solution <Production Example P1 (Production of Copolymer Solution A-1)> A four-necked flask equipped with a thermometer, cooler, stirrer, and dropping funnel was charged with 50 g of xylene and 50 g of butyl acetate as solvents, introduced with nitrogen, and stirred at 88°C. A mixture of monomers (a1), (a2), (b1), and (b2) in the amounts (g) shown in Table 3, and 2.0 g of 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate (initial addition) as a polymerization initiator, was then added dropwise over 3 hours while maintaining the mixture at 88°C. After stirring at 88°C for 1 hour, 0.1 g of 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate was added three times at one-hour intervals. Stirring was then continued at the same temperature for 2 hours, and the mixture was cooled to room temperature to obtain copolymer solution A-1. The heating residue and Mw of A-1 are shown in Table 3.

[0059] <Production Examples P2 to P20 (Production of Copolymer Solutions A-2 to 17, B-1 to 3)> As shown in Tables 3 to 5, copolymer solutions A-2 to A-17 and B-1 to B-3 were obtained by carrying out polymerization reactions in the same manner as in Production Example P1, except that monomers, polymerization initiators, and solvents were used. The heating residue Mw of each polymer is shown in Tables 3 to 5. The numerical values for the raw material formulation amounts in the tables are in g. The proportion (mol %) of monomer (b1) in the tables is calculated by dividing the molar number of monomer (b1) by the total molar number of monomers (a) and (b).

[0060]

Table 3

[0061]

Table 4

[0062]

Table 5

[0063] 1-4. Other Manufacturing Examples <Manufacturing Example C1 (Manufacturing of Gum Rosin Solution)> In a flask equipped with a thermometer, reflux condenser, and stirrer, 300 g of Chinese gum rosin (WW) and 310 g of xylene were added and refluxed under reduced pressure at 70-80°C for 1 hour to obtain a xylene solution of gum rosin (brown, transparent liquid, 50% solids). The resulting solution had a heating residue of 50.3%.

[0064] <Manufacturing Example C2 (Manufacturing of Gum Rosin Zinc Salt Solution)> In a flask equipped with a thermometer, reflux condenser, and stirrer, 240 g of Chinese gum rosin (WW) and 360 g of xylene were added. Subsequently, 120 g of zinc oxide was added to convert all the resin acids in the rosin into zinc salts. The mixture was then refluxed and dehydrated under reduced pressure at 70-80°C for 3 hours. This solution was then cooled and filtered to obtain a xylene solution of gum rosin zinc salt (a thick brown, transparent liquid with a solids content of 50%). The resulting solution had a heating residue of 50.2%.

[0065] 2. Examples 1 to 17 and Comparative Examples 1 to 3 (Production of Coating Compositions) The coating compositions were prepared by mixing the components shown in Tables 6 and 7 at the ratios (mass %) shown in the tables and mixing and dispersing the mixture with glass beads having a diameter of 1.5 to 2.5 mm.

[0066]

Table 6

[0067]

Table 7

[0068] Details of the ingredients in the table are shown below. <Antifouling agent> Cuprous oxide: Trade name "NC-301" (manufactured by Nissin Chemco Co., Ltd.) Copper pyrithione: Trade name "Copper Omadine" (manufactured by Lonza Co., Ltd.)

[0069] <Dissolution Regulator> Gum rosin solution: the material prepared in Preparation Example C1 is used Gum rosin zinc solution: the material prepared in Preparation Example C2 is used

[0070] <Pigment> Bengara: Trade name "BENGARA KINGYOKU" (Made by Morishita Bengara Industry Co., Ltd.) Talc: Trade name "Talc MS" (manufactured by Japan Talc Co., Ltd.) Zinc oxide: Trade name "Zinc Oxide 2" (manufactured by Seido Chemical Industry Co., Ltd.) Titanium dioxide: Trade name "FR-41" (manufactured by Furukawa Machinery & Metal Co., Ltd.)

[0071] <Other additives> Disparlon A603-20X: Amide-based thixotropic agent: Trade name "Disparlon A603-20X" (manufactured by Kusunoki Chemicals Co., Ltd.) Tritolyl phosphate: (manufactured by Dahachi Chemical Industry Co., Ltd.) Tetraethoxysilane: Trade name "Ethyl Silicate 28" (manufactured by Colcoat Co., Ltd.)

[0072] 3. Experiment All coating compositions of Examples and Comparative Examples were placed in sealed containers within 1 hour of production and allowed to stand for 30 days in a thermostat set at 50°C (accelerated degradation treatment) before use. The following tests were performed on the treated coatings.

[0073] <Test Example 1 (Rotation Test)> A rotating drum with a diameter of 515mm and a height of 440mm is installed in the center of the water tank, which is rotated by a motor. A cooling device is also installed to maintain a constant seawater temperature, and an automatic pH controller is used to maintain a constant pH value. A test plate was prepared as follows. First, a rust-proof coating (epoxy-based A / C) was applied to a titanium plate (71 × 100 × 0.5 mm) to a dried thickness of approximately 100 μm to form a rust-proof coating film. Subsequently, the coating compositions obtained in Examples and Comparative Examples were applied to a dried film thickness of approximately 450 μm and dried at 40°C for 3 days to prepare a test plate. The prepared test plate was fixed to the rotating drum of the rotating device of the above apparatus so that it was in contact with seawater. The drum was rotated at a speed of 20 knots. During this period, the seawater temperature was maintained at 15°C and the pH was maintained at 8.0-8.2. The seawater was replaced every two weeks. The remaining film thickness of each test plate was measured at the beginning and every six months after the start of the test using a KEYENCE VK-X100 profiling laser microscope. The dissolved film thickness was calculated from the difference between the two values to obtain the monthly film dissolution amount (μm / month), which was used to evaluate the solubility of the film. The evaluation results are shown in Tables 6 and 7.

[0074] All comparative examples failed to achieve the same results as the examples in terms of maintaining excellent antifouling performance over the long term. To maintain excellent antifouling performance over the long term, the coating film dissolution rate should be maintained at approximately 1.5 to 10 μm / month. However, the coating film dissolution rates in Comparative Examples 1 and 3 were significantly lower, and in Comparative Example 2, the coating gelled after accelerated degradation, making the target test impossible.

Claims

1. An antifouling coating composition comprising a copolymer A and an antifouling agent D, wherein: The copolymer A is a copolymer of a monomer (a) represented by the general formula (1) and an ethylenically unsaturated monomer (b) other than the monomer (a). The monomer (a) is a compound in which n in the general formula (1) is 2 or more, The aforementioned monomer (b) includes a monomer (b1) represented by the general formula (2), The ratio of the monomer (b1) is 0.01 to 2 mol% relative to the total of the monomer (a) and the monomer (b). In the general formula (1), R 1 represents hydrogen or methyl, R 2 represents hydrogen, methyl, phenyl, R 3 represents an alkoxy group having 1 to 8 carbon atoms, or represents an alkyl group having 1 to 8 carbon atoms which may be substituted with a phenyl group, or represents a phenyl group, and n represents an integer of 1 to 10, In the general formula (2), R 4 represents hydrogen or methyl, R 5 represents hydrogen, methyl or phenyl, and m represents an integer from 0 to 10.

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