Water-based antifouling coating composition, antifouling coating film, coated article and method for producing the same

Abstract

Provided is a water-based antifouling coating composition capable of forming an antifouling coating film that is excellent in antifouling properties and water resistance. [Solution] A water-based antifouling coating composition containing a urethane resin (A), a rosin ester compound (B), an antifouling agent (C), and water (D), wherein the acid value of the solid content of the coating composition is 25 mgKOH / g or less.

Description

[Technical Field]

[0001] The present disclosure relates to a water-based antifouling coating composition, an antifouling coating film, a coated article, and a method for producing the same. [Background technology]

[0002] Conventionally, organic solvent diluted compositions have been used as antifouling coating compositions. In recent years, from the viewpoint of environmental conservation or improving the coating work environment, there has been a demand for water-based antifouling coating compositions, i.e., water-based antifouling coating compositions (see, for example, Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 51-014936 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-277680 [Patent Document 3] International Publication No. 2023 / 232825 Summary of the Invention [Problem to be solved by the invention]

[0004] The conversion of antifouling coating compositions to aqueous systems is effective in reducing the amount of volatile organic compounds (VOCs) used. Conventional aqueous antifouling coating compositions often use (meth)acrylic resins as binder resins. However, the antifouling coating films formed from such aqueous antifouling coating compositions often lack sufficient antifouling properties or water resistance.

[0005] An object of the present disclosure is to provide a water-based antifouling coating composition capable of forming an antifouling coating film that is excellent in antifouling properties and water resistance. [Means for solving the problem]

[0006] One embodiment of the water-based antifouling coating composition of the present disclosure contains a urethane resin (A), a rosin ester compound (B), an antifouling agent (C), and water (D), and the acid value of the solid content of the coating composition is 25 mgKOH / g or less. [Effects of the Invention]

[0007] The water-based antifouling coating composition of the present disclosure can form an antifouling coating film that is excellent in antifouling properties and water resistance. DETAILED DESCRIPTION OF THE INVENTION

[0008] In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits. In this specification, when the units of the numerical values ​​before and after "to" indicating a numerical range are the same, the unit of the numerical value before "to" may be omitted. In this specification, when multiple lower limit values ​​and multiple upper limit values ​​are described for a certain element, a numerical range formed by combining a value arbitrarily selected from the described lower limit values ​​and a value arbitrarily selected from the described upper limit values ​​is also considered to be described. Each of the components described in this specification can be used singly or in combination of two or more.

[0009] [Water-based antifouling paint composition] One embodiment of the aqueous antifouling coating composition of the present disclosure (hereinafter also referred to as "the composition") contains a urethane resin (A), a rosin ester compound (B), an antifouling agent (C), and water (D), each of which is explained below.

[0010] The acid value of the solid content of the present composition is preferably 25 mgKOH / g or less, more preferably 1 to 24 mgKOH / g, even more preferably 3 to 22 mgKOH / g, and particularly preferably 5 to 20 mgKOH / g, and may be, for example, 5 to 15 mgKOH / g or 5 to 12 mgKOH / g. The present composition, which contains the above components and has an acid value of the solid content below the above upper limit, can form an antifouling coating film with excellent antifouling properties and water resistance. The antifouling properties are achieved by the gradual release of the antifouling agent (C) in the coating film formed from the present composition, but each component of the present composition, including water (D), must have at least some hydrophilicity. On the other hand, if the hydrophilicity is too high, the coating film formed from the present composition has insufficient water resistance and may disintegrate in the usage environment (underwater). The present inventors focused on the acid value of the solid content of the composition containing the above components and found that both antifouling properties and water resistance can be achieved by adjusting the acid value within the above range. The acid value can be adjusted by adjusting the acid values ​​of the components contained in the composition and the proportions thereof.

[0011] The acid value of the solid content of the composition is measured by the method described in the Examples section. The term "acid value of the solid content of the composition" refers to the acid value of the solid content of the supernatant obtained by subjecting the composition to an ethanol extraction treatment. Details of the ethanol extraction treatment are described in the Examples section.

[0012] The solid content of a substance (e.g., the composition or each component) refers to the heating residue (non-volatile content) when the substance is dried in an incubator at 125°C for 1 hour. Specifically, the heating residue is the residue of the sample (including the residue adhering to the wire) obtained by weighing out 1.0 g of the substance sample onto a flat-bottomed dish, spreading it evenly using a wire of known mass, and drying it in an incubator at 1 atmosphere and 125°C for 1 hour. The solid content percentage (solid content concentration) (mass %) of the substance is calculated from the mass of the heating residue.

[0013] From the viewpoint of coating workability and the like, the content of solids in the present composition is preferably 40 to 80 mass %, more preferably 45 to 75 mass %, and even more preferably 50 to 70 mass %, based on 100 mass % of the present composition.

[0014] <Urethane resin (A)> The urethane resin (A) is a resin containing a reaction product of a polyol and a polyisocyanate, and is a urethane resin obtained by reacting raw material components containing a polyol and a polyisocyanate.

[0015] Polyols are compounds having two or more hydroxy groups in one molecule. Examples of polyols include chain aliphatic diols, alicyclic diols, aromatic ring-containing diols, polycarbonate polyols, polyether polyols, polyester polyols, polyether ester polyols, (meth)acrylic polyols, polyolefin polyols, and aliphatic polyols having three or more hydroxy groups.

[0016] Examples of the chain aliphatic diol include chain aliphatic diols having 2 to 12 carbon atoms and no ether bond, such as ethylene glycol, propylene glycol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 2,5-hexanediol, 3-methyl-1,5-pentanediol, 1,5-heptanediol, 1,7-heptanediol, 1,8-octanediol, 2,2,4-trimethyl-1,3-pentanediol, and 2,4-diethyl-1,5-pentanediol; and chain aliphatic diols having 2 to 12 carbon atoms and an ether bond, such as diethylene glycol, triethylene glycol, dipropylene glycol, and tripropylene glycol. The chain aliphatic diol preferably has 2 to 12 carbon atoms.

[0017] Examples of alicyclic ring-containing diols include hydrogenated bisphenol A, hydrogenated xylylene diol, cyclohexane diol, cyclohexane dimethanol, tricyclodecane dimethanol, and hydrogenated dimer diol. Examples of aromatic ring-containing diols include bisphenol A, xylylenediol, catechol, resorcinol, hydroquinone, and bishydroxyethyl terephthalate.

[0018] The polycarbonate polyol is preferably a polycarbonate diol. Examples of polycarbonate diols include compounds represented by the formula: HO-R-(OC(=O)-OR)n-OH [wherein each R is independently an aliphatic diol residue, and n is the number of repeating units, and is usually an integer of 50 or less, preferably an integer of 5 to 30.] Such polycarbonate diols can be obtained, for example, by a transesterification method in which an aliphatic diol is reacted with a substituted carbonate under conditions in which hydroxy groups are in excess, or by a method in which an aliphatic diol is reacted with phosgene.

[0019] Examples of the aliphatic diol include the chain aliphatic diols described above, preferably chain aliphatic diols having 2 to 12 carbon atoms, more preferably chain aliphatic diols having 2 to 12 carbon atoms and no ether bond, and even more preferably 1,6-hexanediol. Examples of substituted carbonates include aliphatic carbonates such as dimethyl carbonate and diethyl carbonate; aromatic carbonates such as diphenyl carbonate; and cyclic carbonates such as ethylene carbonate.

[0020] The polyether polyol is preferably a polyether diol. Examples of polyether diols include alkylene oxide adducts of the above diols (chain aliphatic diols, alicyclic diols, or aromatic ring-containing diols), and ring-opening polymers of cyclic ethers (e.g., ethylene oxide, propylene oxide, tetrahydrofuran). Specific examples of polyether diols include polyethylene glycol, polypropylene glycol, ethylene glycol-propylene glycol (block or random) copolymers, polytetramethylene glycol, polyhexamethylene glycol, and polyoctamethylene glycol.

[0021] Aliphatic polyols having three or more hydroxy groups include, for example, glycerin, trimethylolpropane (TMP), pentaerythritol, and sorbitol.

[0022] Among the polyols for forming the urethane resin (A), at least one selected from the group consisting of polycarbonate polyols and polyether polyols is preferred, and polycarbonate polyols and polyether polyols are more preferred, from the viewpoint of being able to suppress the acid value and form an antifouling coating film that is excellent in antifouling properties and water resistance.

[0023] Polyisocyanates are compounds having two or more isocyanate groups in one molecule, and examples of polyisocyanates include polyisocyanate monomers and polyisocyanate derivatives. Examples of the polyisocyanate monomer include chain aliphatic polyisocyanates, alicyclic polyisocyanates, and aromatic ring-containing polyisocyanates.

[0024] Examples of the chain aliphatic polyisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate (HMDI), 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, and 2,6-diisocyanatohexanoic acid. diisocyanates such as methyl 2,6-diisocyanatohexanoate; and triisocyanates such as 2-isocyanatoethyl 2,6-diisocyanatohexanoate, 1,6-diisocyanato-3-isocyanatomethylhexane, 1,4,8-triisocyanatooctane, 1,6,11-triisocyanatoundecane, 1,8-diisocyanato-4-isocyanatomethyloctane, 1,3,6-triisocyanatohexane, and 2,5,7-trimethyl-1,8-diisocyanato-5-isocyanatomethyloctane.

[0025] Examples of alicyclic ring-containing polyisocyanates include diisocyanates such as cyclohexane diisocyanate, isophorone diisocyanate (IPDI), norbornane diisocyanate, methylene bis(cyclohexyl isocyanate) (hydrogenated diphenylmethane diisocyanate), and bis(isocyanatomethyl)cyclohexane (hydrogenated xylylene diisocyanate); and triisocyanates such as 1,3,5-triisocyanatocyclohexane and 1,3,5-trimethylisocyanatocyclohexane.

[0026] Examples of aromatic ring-containing polyisocyanates include diisocyanates such as m-phenylene diisocyanate, p-phenylene diisocyanate, tolylene diisocyanate, toluidine diisocyanate, naphthalene diisocyanate, 4,4'-diphenyl diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenylether diisocyanate, and xylylene diisocyanate; triisocyanates such as 1,3,5-triisocyanatomethylbenzene, triphenylmethane-4,4',4''-triisocyanate, 1,3,5-triisocyanatobenzene, and 2,4,6-triisocyanatotoluene; and tetraisocyanates such as 4,4'-diphenylmethane-2,2',5,5'-tetraisocyanate.

[0027] Examples of polyisocyanate derivatives include multimers such as dimers and trimers of the above polyisocyanate monomers, isocyanurates, allophanates, biurets, and polyol-modified products (alcohol adducts). Examples of polyisocyanate derivatives include polymethylene polyphenylene polyisocyanates.

[0028] Among the polyisocyanates for forming the urethane resin (A), from the viewpoint of being able to suppress the acid value and form an antifouling coating film that is excellent in antifouling properties and water resistance, at least one selected from the group consisting of chain aliphatic polyisocyanates and alicyclic polyisocyanates is preferred, at least one selected from the group consisting of chain aliphatic diisocyanates and alicyclic diisocyanates is more preferred, and at least one selected from the group consisting of HMDI and IPDI is even more preferred.

[0029] When synthesizing the urethane resin (A), conventionally known compounds that have been used in synthesizing urethane resins, such as compounds having two or more hydroxy groups and one or more carboxy groups or their salts in one molecule, compounds having two or more amino groups and one or more sulfo groups or their salts in one molecule, and other compounds having anionic groups, as well as nonionic compounds, may be used. Examples of anionic groups include carboxy groups, sulfo groups, and salts thereof.

[0030] Examples of the compound having an anionic group include dihydroxyalkanoic acids such as 2,2-dimethylolpropionic acid and 2,2-dimethylolbutanoic acid and salts thereof; 2-(2-aminoethylamino)-ethanesulfonic acid and salts thereof, 2-(3-aminopropylamino)-ethanesulfonic acid and salts thereof, and 2,4-diaminobenzenesulfonic acid and salts thereof. The acid value of the urethane resin (A) can be adjusted by the above compound having an anionic group. Examples of the nonionic compound include poly(oxyalkylene) alkenyl ethers, poly(oxyalkylene) aryl alkyl ethers, poly(oxyalkylene) alkylaryl phenyl ethers, poly(oxyalkylene) propenyl alkyl ethers, poly(oxyalkylene) alkylpropenyl alkyl ethers, poly(oxyalkylene) alkylpropenyl phenyl ethers, poly(oxyalkylene) aryloxyalkyl ethers, and poly(oxyalkylene) styrenated propenyl phenyl ethers.

[0031] From the viewpoint of obtaining a coating film with superior antifouling properties, the urethane resin (A) preferably has a poly(oxyalkylene) structure (also referred to as a polyether structure). As such a urethane resin (A), a urethane resin having a structural unit derived from the above-mentioned polyether polyol such as the above-mentioned polyether diol is preferred. In this case, the content of the poly(oxyalkylene) structure in the urethane resin (A), in terms of oxyalkylene units, is preferably 1.0 to 15.0 mol, more preferably 1.0 to 10.0 mol, even more preferably 1.0 to 5.0 mol, and particularly preferably 2.0 to 4.0 mol, per 1 mol of the content of the structural unit derived from the polyisocyanate.

[0032] The urethane resin (A) preferably has a carbonate group (-OC(=O)-O-) from the viewpoint of obtaining a coating film with more excellent antifouling properties. Such urethane resin (A) is preferably a urethane resin having a structural unit derived from the above-mentioned polycarbonate polyol, such as the above-mentioned polycarbonate diol.

[0033] The urethane resin (A) preferably has a poly(oxyalkylene) structure and a carbonate group, from the viewpoint of obtaining a coating film with more excellent antifouling properties. As such a urethane resin (A), a urethane resin having a structural unit derived from the above polyether polyol and a structural unit derived from the above polycarbonate polyol is preferred. In this case, the content of the poly(oxyalkylene) structure in the urethane resin (A) is preferably 0.1 to 2.0 mol, more preferably 0.3 to 1.0 mol, calculated as an oxyalkylene unit, per 1 mol of the carbonate group content.

[0034] The structure of the urethane resin (A) can be analyzed by nuclear magnetic resonance spectroscopy (NMR).

[0035] The urethane resin (A) may have acid groups such as carboxyl groups neutralized with a neutralizing agent, such as an amine compound such as diethylamine, triethylamine, 2-dimethylaminoethanol, or dibutylamine.

[0036] The urethane resin having the structural units derived from the polyether polyol and the structural units derived from the polycarbonate polyol can be obtained, for example, by mixing a polycarbonate polyol, a polyether polyol, optionally the compound having an anionic group or the nonionic compound, and an organic solvent, and then adding a polyisocyanate and optionally a known catalyst to the resulting mixture and reacting them. If desired, a neutralization treatment may be performed. Water is added to the resulting urethane resin solution, and the organic solvent is removed to obtain an aqueous dispersion of the urethane resin.

[0037] The acid value of the urethane resin (A) is preferably 25 mgKOH / g or less, more preferably 20 mgKOH / g or less, even more preferably 15 mgKOH / g or less, even more preferably 10 mgKOH / g or less, and particularly preferably 6 mgKOH / g or less or 3 mgKOH / g or less. The acid value of the urethane resin (A) may be 0 mgKOH / g or more, for example, 0.1 mgKOH / g or more, 0.3 mgKOH / g or more, or even 0.5 mgKOH / g or more. By using a urethane resin with such an acid value, the acid value of the composition can be easily adjusted to the above-mentioned range, resulting in an antifouling coating film with excellent antifouling and water resistance. The acid value of the urethane resin (A) is measured by the same method as the acid value measurement and heating residue measurement method described in the "Acid Value" section of the Examples section.

[0038] From the viewpoint of easily forming an antifouling coating film that has an excellent balance of crack resistance and antifouling properties, the glass transition temperature (Tg) of the urethane resin (A) is preferably −30 to 90° C., more preferably −20 to 70° C., and even more preferably −15 to 60° C. The Tg of the urethane resin (A) is the temperature (° C.) at the onset value of DSC during heating, obtained by measuring the change in heat quantity in the range of −50 to 250° C. at a heating rate of 20° C. / min using a differential scanning calorimetry (DSC) device in a nitrogen atmosphere.

[0039] The urethane resin (A) can be synthesized by a conventionally known method, such as solution polymerization, suspension polymerization, emulsion polymerization, seed polymerization, miniemulsion polymerization, microemulsion polymerization, or emulsifier-free (soap-free) emulsion polymerization. The aqueous dispersion of the urethane resin (A) can also be obtained by a known method, such as phase inversion emulsification, D-phase emulsification, forced emulsification, gel emulsification, inversion emulsification, or high-pressure emulsification.

[0040] The urethane resin (A) is preferably, for example, a water-dispersible urethane resin that can be dispersed in water, or a water-soluble urethane resin that can be dissolved in water, and more preferably a water-dispersible urethane resin. The urethane resin (A) may be present in the composition in the form of particles. For example, when the composition is applied and dried, water evaporates, causing the particles to bond together and form a film. Therefore, the present composition preferably contains emulsion particles of the urethane resin (A), that is, the urethane resin (A) is preferably contained in the present composition in the form of a resin emulsion.

[0041] The present composition may contain one type of urethane resin (A) or two or more types. The content of the urethane resin (A) is, for example, 3% by mass or more, preferably 3 to 30% by mass, more preferably 4 to 25% by mass, and even more preferably 5 to 20% by mass, based on 100% by mass of the solid content of the composition. When the composition contains a urethane-type thickener (described below) that corresponds to the urethane resin (A), the urethane-type thickener is also included in the urethane resin (A) in calculating the content ratio.

[0042] In the production of the present composition, from the viewpoint of the coating film properties, it is preferable to use an aqueous dispersion of the urethane resin (A), and it is more preferable to use an aqueous emulsion of the urethane resin (A), which makes it easier for the urethane resin (A) to be present stably and uniformly in the present composition, and tends to enable the formation of a coating film with uniform coating film properties.

[0043] The Z-average particle size of the urethane resin (A) particles in the above-mentioned aqueous emulsion is preferably 10 to 2,000 nm, more preferably 20 to 1,000 nm, even more preferably 30 to 500 nm, and particularly preferably 50 to 400 nm. Urethane resin (A) having a Z-average particle size within the above range tends to be able to exist stably in the aqueous antifouling coating composition, and such a composition tends to be able to form a coating film with uniform coating film properties. In this specification, the Z-average particle size is measured at 23°C by dynamic light scattering (DLS) using a DLS measurement device (for example, Zetasizer Nano-ZS ZEN3600 manufactured by Malvern).

[0044] The content of the urethane resin (A) in the aqueous dispersion is preferably 15 to 80 mass %, more preferably 20 to 70 mass %, and even more preferably 25 to 65 mass %, from the viewpoints of the stability of the dispersion and the workability in the production of the coating material.

[0045] The aqueous dispersion of urethane resin (A) is a dispersion in which urethane resin (A) is dispersed in a dispersion medium containing water (hereinafter also referred to as "aqueous medium"). The aqueous medium is not particularly limited as long as it contains water. From the viewpoint of reducing the environmental load, the water content in the aqueous medium is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, still more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

[0046] The aqueous medium may contain a medium other than water. Examples of such a medium include acetone, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, diacetone alcohol, dioxane, ethylene glycol, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol monopropyl ether, and ethylene glycol monohexyl ether. The above-mentioned medium may be one type or two or more types.

[0047] The pH of the aqueous dispersion of urethane resin (A) at 23°C is preferably 7.0 to 12.0, more preferably 7.0 to 11.0, and even more preferably 7.0 to 10.0, from the viewpoint of the stability of the aqueous dispersion. By using such an aqueous dispersion, for example, the urethane resin (A) tends to be present stably and uniformly in the composition. Therefore, the composition can be used to form a coating film with uniform coating film properties. The pH is a value measured when 5 g of the aqueous dispersion of urethane resin (A) is diluted with water to a total amount of 50 g.

[0048] <Rosin ester compound (B)> Examples of the rosin ester compound (B) include esters of unmodified rosin with alcohol, and esters of rosin derivatives (excluding esters) with alcohol. The present composition, which contains the rosin ester compound (B) in addition to the urethane resin (A), can form an antifouling coating film with excellent antifouling properties. By using the rosin ester compound (B), the acid value of the present composition can be easily adjusted to the above-mentioned range, compared to when using, for example, rosin, which is a free acid (free rosin acid) or acid-modified rosin, and an antifouling coating film with excellent antifouling properties and water resistance and reduced discoloration in the dry-wet alternating portions described below can be obtained.

[0049] Examples of rosins include natural resins (natural rosins) obtained from pine trees, specifically gum rosin, tall oil rosin, and wood rosin. Examples of components constituting rosin include abietic acid, neoabietic acid, dehydroabietic acid, secodehydroabietic acid, dihydroabietic acid, tetrahydroabietic acid, pimaric acid, isopimaric acid, levopimaric acid, palustric acid, and sandaracopimaric acid. The above components constituting rosin may be one type or two or more types.

[0050] Examples of rosin derivatives (excluding esters) include hydrogenated rosin, disproportionated rosin, polymerized rosin (also called dimerized rosin), acid-modified rosin, and rosin-modified phenolic resin. Examples of acid-modified rosin include maleic acid-modified rosin, maleic anhydride-modified rosin, fumaric acid-modified rosin, and (meth)acrylic acid-modified rosin. The rosin derivative may be one type or two or more types.

[0051] Rosin and rosin derivatives may be in the form of salts. Examples of these salts include ammonium salts and metal salts (saponified rosin and saponified rosin derivatives). Examples of the metal salts include alkali metal salts such as sodium salts and potassium salts, as well as zinc salts, copper salts, aluminum salts, magnesium salts, calcium salts, and barium salts.

[0052] The alcohol is preferably a polyhydric alcohol. The polyhydric alcohol is a compound having two or more alcoholic hydroxy groups, preferably 2 to 10, more preferably 2 to 8, still more preferably 3 to 6, and particularly preferably 3 to 4. In one embodiment, the polyhydric alcohol is a trihydric or higher polyhydric alcohol having three or more alcoholic hydroxy groups.

[0053] Examples of polyhydric alcohols include: Aliphatic diols preferably having 20 or less carbon atoms, more preferably 10 or less carbon atoms, and even more preferably 6 or less carbon atoms, such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, and 1,4-cyclohexanedimethanol; and trihydric or higher aliphatic alcohols preferably having 20 or less carbon atoms, more preferably 10 or less carbon atoms, and even more preferably 6 or less carbon atoms, such as glycerin, diglycerin, trimethylolethane, trimethylolpropane, butanetriol, pentanetriol, hexanetriol, pentaerythritol, dipentaerythritol, glucose, sucrose, and sorbitol; Examples include:

[0054] Among alcohols, polyhydric alcohols are preferred, trihydric or higher polyhydric alcohols are more preferred, trihydric or higher aliphatic alcohols are even more preferred, and glycerin or pentaerythritol is particularly preferred. That is, as the rosin ester compound (B), esters of rosin or its derivatives with polyhydric alcohols are preferred, esters of rosin or its derivatives with trihydric or higher polyhydric alcohols are more preferred, esters of rosin or its derivatives with trihydric or higher aliphatic alcohols are even more preferred, and esters of rosin or its derivatives with glycerin, or esters of rosin or its derivatives with pentaerythritol are particularly preferred.

[0055] Specific examples of the rosin ester compound (B) include rosin ester, hydrogenated rosin ester, disproportionated rosin ester, polymerized rosin ester, acid-modified rosin ester, and rosin ester-modified phenolic resin. Among these, rosin ester, hydrogenated rosin ester, disproportionated rosin ester, polymerized rosin ester, and acid-modified rosin ester are preferred.

[0056] In one embodiment, the composition may further contain at least one component selected from the group consisting of rosin, ammonium salts of rosin, and metal salts of rosin (saponified rosin) in addition to the rosin ester compound (B). Examples of metal salts of rosin include alkali metal salts such as sodium salts and potassium salts, as well as zinc salts, copper salts, aluminum salts, magnesium salts, calcium salts, and barium salts.

[0057] The weight average molecular weight (Mw) of the rosin ester compound (B) is preferably 300 to 3,000, more preferably 400 to 2,800, even more preferably 600 to 2,600, still more preferably 800 to 2,400, and particularly preferably 1,000 to 2,000.

[0058] The weight-average molecular weight (Mw) of the rosin ester compound (B) is a value calculated as a standard polystyrene by gel permeation chromatography (GPC). Details of the measurement conditions are described in the Examples section.

[0059] The acid value of the rosin ester compound (B) is preferably 100 mgKOH / g or less, more preferably 80 mgKOH / g or less, even more preferably 60 mgKOH / g or less, still more preferably 40 mgKOH / g or less, and particularly preferably 20 mgKOH / g or less. By using a rosin ester compound having such an acid value, the acid value of the present composition can be easily adjusted to fall within the above-mentioned range, and an antifouling coating film having excellent antifouling properties and water resistance can be obtained.

[0060] The lower limit of the acid value of the rosin ester compound (B) is not particularly limited. The acid value of the rosin ester compound (B) may be, for example, 0 mgKOH / g or more, 5 mgKOH / g or more, or 10 mgKOH / g or more.

[0061] The acid value of the rosin ester compound (B) is measured by the same method as in the acid value measurement and heating residue measurement method <Acid value> described in the Examples section.

[0062] The rosin ester compound (B) is preferably in the form of water-dispersible particles that can be dispersed in water. The rosin ester compound (B) may be present in the coating composition in the form of particles.

[0063] The present composition may contain one or more of the above compounds (B). In the present composition, the ratio of the content of the rosin ester compound (B) to the content of the urethane resin (A) (content of (B) / content of (A)) is preferably 0.3 to 4.0 by mass, more preferably 0.7 to 3.0, even more preferably 0.9 to 2.8, still more preferably 1.2 to 2.5, and particularly preferably 1.4 to 2.2. The present composition in this embodiment can form an antifouling coating film with excellent antifouling properties.

[0064] The content of the rosin ester compound (B) is preferably 3 to 40 mass%, more preferably 5 to 35 mass%, and even more preferably 10 to 30 mass%, based on 100 mass% of the solids content of the composition. The composition of this embodiment can form an antifouling coating film with even more excellent antifouling properties.

[0065] In producing the present composition, from the viewpoint of coating film properties, it is preferable to use an aqueous dispersion of the rosin ester compound (B), and it is more preferable to use an aqueous emulsion of the rosin ester compound (B), which makes it easier for the rosin ester compound (B) to be stably and uniformly present in the present composition, and tends to enable the formation of a coating film with uniform coating film properties.

[0066] The Z-average particle size of the rosin ester compound (B) in the above-mentioned aqueous emulsion is preferably 10 to 2,000 nm, more preferably 20 to 1,000 nm, even more preferably 30 to 500 nm, and particularly preferably 50 to 300 nm. A rosin ester compound (B) having a Z-average particle size within the above range tends to be able to exist stably in an aqueous antifouling coating composition, and such a composition tends to be able to form a coating film with uniform coating film properties.

[0067] The content of the rosin ester compound (B) in the aqueous dispersion is preferably 20 to 80 mass %, more preferably 30 to 75 mass %, and even more preferably 40 to 70 mass %, from the viewpoints of the stability of the dispersion and the workability in the production of the coating material.

[0068] The aqueous dispersion of the rosin ester compound (B) is a dispersion in which the rosin ester compound (B) is dispersed in an aqueous medium. The aqueous medium is not particularly limited as long as it contains water. From the viewpoint of reducing the environmental load, the water content in the aqueous medium is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more. Specific examples of the medium other than water in the aqueous medium are as described above.

[0069] The pH of the aqueous dispersion of the rosin ester compound (B) at 23°C is preferably 6.0 to 12.0, more preferably 6.0 to 10.0, even more preferably 6.0 to 9.0, and particularly preferably 6.0 to 8.5, from the viewpoints of the stability of the aqueous dispersion of the rosin ester compound (B) and the stability of the urethane resin (A) in the composition. The pH is a value measured when 5 g of the aqueous dispersion of the rosin ester compound (B) is diluted with water to a total amount of 50 g.

[0070] <Anti-fouling agent (C)> The composition further contains an antifouling agent (C). Examples of the antifouling agent (C) include inorganic antifouling agents and organic antifouling agents.

[0071] Examples of inorganic antifouling agents include copper or copper compounds (excluding pyrithione compounds) such as cuprous oxide, metallic copper powder, and cuprous thiocyanate (copper rhodanide). Among these, cuprous oxide is preferred.

[0072] Examples of organic antifouling agents include: Metal pyrithiones (pyrithione compounds) such as copper pyrithione and zinc pyrithione; tetraalkylthiuram disulfides such as tetramethylthiuram disulfide; Carbamate compounds such as zinc dimethyldithiocarbamate, zinc ethylenebisdithiocarbamate, and bisdimethyldithiocarbamoylzinc ethylenebisdithiocarbamate; maleimide compounds such as 2,4,6-triphenylmaleimide, 2,3-dichloro-N-(2',6'-diethylphenyl)maleimide, and 2,3-dichloro-N-(2'-ethyl-6'-methylphenyl)maleimide; 2,4,5,6-tetrachloroisophthalonitrile, N,N-dimethyldichlorophenylurea, 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one, 2-methylthio-4-tert-butylamino-6-cyclopropyl-S-triazine, chloromethyl-n-octyl disulfide, N',N'-dimethyl-N-phenyl-(N-fluorodichloromethylthio)sulfamide, and N',N'-dimethyl-N-tolyl-(N-fluorodichloromethylthio)sulfamide; Amine-organoborane complexes such as pyridinetriphenylborane and 4-isopropylpyridinediphenylmethylborane; and (+ / -)-4-[1-(2,3-dimethylphenyl)ethyl]-1H-imidazole (hereinafter also referred to as "medetomidine"); Examples include:

[0073] Among the organic antifouling agents, at least one selected from the group consisting of copper pyrithione, zinc pyrithione, zinc ethylenebisdithiocarbamate, 2-methylthio-4-tert-butylamino-6-cyclopropyl-S-triazine and medetomidine is preferred, at least one selected from the group consisting of copper pyrithione and medetomidine is more preferred, and copper pyrithione and medetomidine are particularly preferred.

[0074] The composition may contain one or more antifouling agents (C). The content of the antifouling agent (C) in the present composition is preferably 0.01 to 80 mass%, more preferably 0.1 to 75 mass%, even more preferably 1 to 70 mass%, still more preferably 5 to 70 mass%, and particularly preferably 10 to 70 mass%, based on 100 mass% of the solid content of the present composition.

[0075] <Water(D)> This composition is a water-based antifouling coating composition. A "water-based" coating composition refers to a coating composition containing water. Examples of water (D) include tap water, ion-exchanged water, and deionized water, with ion-exchanged water or deionized water being preferred. Examples of water (D) include the water contained in the aqueous dispersion of the urethane resin (A), the water contained in the aqueous dispersion of the rosin ester compound (B), and the water contained in the aqueous dispersion of the (meth)acrylic resin described below.

[0076] From the viewpoints of reducing the environmental load and improving coating workability, the content of water (D) in the composition is preferably 20 to 60 mass%, more preferably 23 to 55 mass%, and even more preferably 25 to 50 mass%, based on 100 mass% of the composition. The content of water (D) is measured according to the Karl Fischer method using a moisture meter (e.g., CA-310, manufactured by Nitto Seiko Analytech).

[0077] <Other synthetic resins> The present composition may further contain a synthetic resin other than the urethane resin (A) (hereinafter also referred to as "other synthetic resin"). Examples of the other synthetic resin include a (meth)acrylic resin and a styrene-based resin. The acid value of the solid content of the present composition may be adjusted by using the other synthetic resin.

[0078] The (meth)acrylic resin has a structural unit derived from a (meth)acrylic monomer, and may further have a structural unit derived from an ethylenically unsaturated monomer copolymerizable with the (meth)acrylic monomer (hereinafter also referred to as "other ethylenically unsaturated monomer"). The (meth)acrylic resin may be a homopolymer of a (meth)acrylic monomer, a copolymer of two or more (meth)acrylic monomers, or a copolymer of a (meth)acrylic monomer and another ethylenically unsaturated monomer. The copolymer may be, for example, a random copolymer or a block copolymer. The (meth)acrylic resin may have two or more types of structural units derived from a (meth)acrylic monomer. The (meth)acrylic resin may have one type, or two or more types, of structural units derived from another ethylenically unsaturated monomer.

[0079] In this specification, the term "(meth)acrylate" can mean either acrylate or methacrylate. The term "(meth)acrylic" can mean either acrylic or methacrylic. The term "(meth)acrylic acid" can mean either acrylic acid or methacrylic acid.

[0080] Examples of the (meth)acrylic monomer include (meth)acrylic acid esters, (meth)acrylic acid amides, (meth)acrylonitrile, and (meth)acrylic acid.

[0081] Examples of (meth)acrylic acid esters include alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and lauryl (meth)acrylate; cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate; aryl (meth)acrylates such as phenyl (meth)acrylate; aralkyl (meth)acrylates such as benzyl (meth)acrylate; 2-hydroxy (meth)acrylates such as hydroxy (meth)acrylate; hydroxyalkyl (meth)acrylates such as hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; alkoxyalkyl (meth)acrylates such as methoxybutyl (meth)acrylate, methoxyethyl (meth)acrylate, and ethoxybutyl (meth)acrylate; epoxy group-containing (meth)acrylates such as glycidyl (meth)acrylate; and aminoalkyl (meth)acrylates such as aminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, and butylaminoethyl (meth)acrylate.

[0082] Examples of (meth)acrylic acid amides include (meth)acrylic acid aminoalkylamides such as aminoethyl(meth)acrylamide, dimethylaminomethyl(meth)acrylamide, and methylaminopropyl(meth)acrylamide; and other amide group-containing (meth)acrylic monomers such as (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-methylol(meth)acrylamide, methoxybutyl(meth)acrylamide, and diacetone(meth)acrylamide.

[0083] Other ethylenically unsaturated monomers include, for example, α-olefins such as ethylene, propylene, and 1-butene; conjugated dienes such as 1,3-butadiene, isoprene, and chloroprene; styrenic monomers such as styrene, α-methylstyrene, vinyltoluene, and halogenated styrenes; vinyl esters such as vinyl acetate and vinyl propionate; unsaturated monocarboxylic acids such as crotonic acid; unsaturated dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid; monoesters of unsaturated dicarboxylic acids such as ethyl maleate and butyl maleate; and diesters of unsaturated dicarboxylic acids such as diethyl maleate and dibutyl maleate.

[0084] In the (meth)acrylic resin, the content of structural units derived from (meth)acrylic monomers in the total amount (100% by mass) of structural units derived from polymerizable monomers is preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 40% by mass or more, still more preferably 50% by mass or more, and particularly preferably 60% by mass or more. In this specification, the content of the structural units is measured by nuclear magnetic resonance spectroscopy (NMR).

[0085] In the (meth)acrylic resin, the content of structural units derived from other ethylenically unsaturated monomers in the total amount (100% by mass) of structural units derived from polymerizable monomers is preferably 80% by mass or less, more preferably 70% by mass or less, even more preferably 60% by mass or less, still more preferably 50% by mass or less, and particularly preferably 40% by mass or less.

[0086] Examples of the (meth)acrylic resin include a (meth)acrylic monomer polymer, which is a homopolymer or copolymer of a (meth)acrylic monomer, a (meth)acrylic monomer-styrene monomer copolymer, and a (meth)acrylic monomer-vinyl ester copolymer. The (meth)acrylic resin may be, for example, a silicone-modified resin. The (meth)acrylic resin may be either a self-crosslinking type or a non-self-crosslinking type.

[0087] Examples of styrene-based resins include homopolymers or copolymers of styrene-based monomers, and copolymers of styrene-based monomers with monomers copolymerizable therewith. Examples of styrene-based monomers include styrene, α-methylstyrene, vinyltoluene, and halogenated styrenes, with styrene being preferred among these. Examples of monomers copolymerizable with styrene-based monomers include the other ethylenically unsaturated monomers described above (excluding styrene-based monomers). The styrene-based resin may be, for example, a silicone-modified product.

[0088] In this specification, styrene-based resins exclude (meth)acrylic resins. That is, resins having structural units derived from (meth)acrylic monomers and structural units derived from styrene-based monomers are classified as (meth)acrylic resins.

[0089] The other synthetic resin is preferably, for example, a water-dispersible resin that can be dispersed in water, or a water-soluble resin that can be dissolved in water, and more preferably a water-dispersible resin. The other synthetic resin may be present in the composition in the form of particles. The other synthetic resin may have, for example, a hydrophilic group such as a carboxy group or a hydroxy group.

[0090] The present composition may contain one or more other synthetic resins. When the present composition contains other synthetic resins, the content of the other synthetic resins is preferably 1 to 100 parts by mass, more preferably 3 to 80 parts by mass, and even more preferably 4 to 70 parts by mass per 100 parts by mass of the urethane resin (A).

[0091] When a (meth)acrylic resin is used as the other synthetic resin, it is preferable to use an aqueous dispersion of the (meth)acrylic resin, and more preferably an aqueous emulsion of the (meth)acrylic resin, in the production of the present composition from the viewpoint of the physical properties of the coating film. This makes it easier for the (meth)acrylic resin to be present stably and uniformly in the present composition, and tends to enable the formation of a coating film with uniform physical properties.

[0092] The aqueous emulsion of the (meth)acrylic resin may be prepared, for example, by emulsifying the (meth)acrylic resin using a surfactant, or may be prepared directly by emulsion polymerization of a polymerizable monomer that forms the (meth)acrylic resin. The surfactant is not particularly limited and can be appropriately selected from cationic surfactants, anionic surfactants, and nonionic surfactants.

[0093] The Z-average particle size of the (meth)acrylic resin particles in the above-mentioned aqueous emulsion is preferably 10 to 2,000 nm, more preferably 20 to 1,000 nm, even more preferably 30 to 500 nm, and particularly preferably 50 to 400 nm. A (meth)acrylic resin having a Z-average particle size within the above range tends to be able to exist stably in an aqueous antifouling coating composition, and such a composition tends to be able to form a coating film with uniform coating film properties.

[0094] The content of the (meth)acrylic resin in the aqueous dispersion is preferably 20 to 80% by mass, more preferably 30 to 75% by mass, and even more preferably 40 to 70% by mass, from the viewpoints of dispersion stability and workability in paint production.

[0095] The aqueous dispersion of a (meth)acrylic resin is a dispersion in which a (meth)acrylic resin is dispersed in an aqueous medium. The aqueous medium is not particularly limited as long as it contains water. The water content in the aqueous medium and specific examples of the medium other than water in the aqueous medium are as described above.

[0096] The pH of the aqueous dispersion of the (meth)acrylic resin at 23°C is preferably 7.0 to 12.0, more preferably 7.0 to 10.0, and even more preferably 7.0 to 9.0, from the viewpoint of the stability of the aqueous dispersion. By using such an aqueous dispersion, for example, the (meth)acrylic resin tends to be stably and uniformly present in the composition. Therefore, the composition can be used to form a coating film with uniform coating film properties. The pH is a value measured when 5 g of the aqueous dispersion of the (meth)acrylic resin is diluted with water to a total amount of 50 g.

[0097] <Other ingredients> The composition may further contain components other than those described above, such as pigments and additives (hereinafter also referred to as "other components"), such as dispersants, antifoaming agents, thickeners, film-forming aids, surface conditioners, antifungal agents, preservatives, pH adjusters, ultraviolet absorbers, and antioxidants. The composition may contain one or more other ingredients.

[0098] Examples of pigments include extender pigments and coloring pigments. Examples of pigments include organic pigments and inorganic pigments. The composition may contain one or more pigments.

[0099] Examples of extender pigments include talc, silica, mica, clay, potassium feldspar, calcium carbonate, kaolin, alumina white, white carbon, aluminum hydroxide, magnesium carbonate, barium carbonate, barium sulfate, zinc oxide, and zinc sulfide. When the present composition contains a body pigment, the content of the body pigment is preferably 0.1 to 80 mass %, more preferably 1 to 70 mass %, and even more preferably 5 to 60 mass %, based on 100 mass % of the solid content of the present composition.

[0100] Examples of color pigments include organic pigments and inorganic pigments. Examples of organic pigments include naphthol red and phthalocyanine blue. Examples of inorganic pigments include carbon black, red iron oxide, titanium dioxide, yellow iron oxide, black iron oxide, and red iron oxide. When the present composition contains a color pigment, the content of the color pigment is preferably 0.01 to 40 mass%, more preferably 0.1 to 30 mass%, and even more preferably 0.5 to 20 mass%, based on 100 mass% of the solid content of the present composition.

[0101] The dispersant is preferably a material that can improve the dispersibility of water-insoluble components (e.g., pigments) in the coating composition. The use of a dispersant, for example, can easily form a coating film with a good appearance and excellent crack resistance. Examples of dispersants include polymers having a pigment-adsorbing group (pigment-affinity group) and a compatible chain, such as fatty acid, polyamino, polyether, polyester, and poly(meth)acrylate. Examples of pigment-adsorbing groups include carboxyl groups, acid anhydride groups, phosphate groups, amino groups, salt groups of these, and ammonium salt groups. When the composition contains a dispersant, the content of the dispersant is preferably 0.1 to 5 mass %, more preferably 0.2 to 3 mass %, based on 100 mass % of the solid content of the composition. For example, a product called a dispersant may contain water or an organic solvent. In such cases, the content of the dispersant refers to the content of the solid content of the dispersant. The same applies to the components described below (excluding the film-forming aid).

[0102] The defoaming agent is preferably a material that can suppress the generation of bubbles during the production or application of the coating composition, or a material that can break down bubbles that have formed in the coating composition.The use of a defoaming agent can, for example, suppress the generation of bubble marks or pinholes in the coating film, thereby improving the film-forming properties and crack resistance of the coating film.Examples of defoaming agents include silicone-based defoaming agents, polymer-based (non-silicone-based) defoaming agents, and mineral oil-based defoaming agents. When the present composition contains an antifoaming agent, the content of the antifoaming agent is preferably 0.05 to 5 mass %, more preferably 0.1 to 3 mass %, based on 100 mass % of the solid content of the present composition.

[0103] Examples of thickeners include alkali thickeners, nonionic association thickeners, acrylic thickeners, urethane thickeners, water-soluble polymer thickeners, and polyamide thickeners; and cellulose derivatives such as hydroxyalkyl cellulose which may be hydrophobically modified. Note that urethane thickeners may also be included in the urethane resin (A). When the present composition contains a thickener, the content of the thickener is preferably 0.01 to 5 mass %, more preferably 0.1 to 3 mass %, based on 100 mass % of the solid content of the present composition.

[0104] Examples of the coalescent include alcohols, glycol ethers, and esters. Examples of the alcohols include isopropyl alcohol and 2,2,4-trimethylpentanediol. Examples of the glycol ethers include ethylene glycol monobutyl ether, ethylene glycol diethyl ether, diethylene glycol monobutyl ether, diethylene glycol diethyl ether, propylene glycol diethyl ether, dipropylene glycol diethyl ether, dipropylene glycol methyl ether, and dipropylene glycol n-butyl ether. Examples of the esters include 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate. When the present composition contains a coalescing agent, the content of the coalescing agent is preferably 0.1 to 15 mass %, more preferably 0.5 to 10 mass %, relative to 100 mass % of the total amount of the present composition.

[0105] <Method of manufacturing a water-based antifouling coating composition> The present composition can be produced, for example, by charging the urethane resin (A), the rosin ester compound (B), the antifouling agent (C), water (D), and, if necessary, the other synthetic resins described above, and, if necessary, the other components described above, all at once or in any order into a stirring vessel, mixing the components using a known device such as a mixer, disperser, or stirrer, and dispersing or dissolving the components in the water (D).

[0106] Examples of the device include a paint shaker, homogenizer, high-speed disperser, sand grind mill, basket mill, ball mill, three-roll mill, ring mill, Ross mixer, and planetary mixer. Mixing (kneading) may be performed with heating or cooling depending on the season, environment, etc.

[0107] In producing the present composition, from the viewpoint of workability in paint production and the like, it is preferable to use an aqueous dispersion of the urethane resin (A) and an aqueous dispersion of the rosin ester compound (B), and it is more preferable to use an aqueous emulsion of the urethane resin (A) and an aqueous emulsion of the rosin ester compound (B). Details of each aqueous dispersion are as described above.

[0108] The content of volatile organic compounds (VOCs) such as organic solvents in the composition is preferably 150 g / L or less, more preferably 100 g / L or less, from the viewpoint of consideration for the natural environment and the painting work environment. The lower the VOC content in the composition, the better, but the content may be, for example, 1 g / L or more, 5 g / L or more, 10 g / L or more, 20 g / L or more, or 30 g / L or more. The VOC content in the composition may be, for example, 1 to 150 g / L.

[0109] The VOC content in the composition is calculated based on the following formula (1) using the values ​​of the composition specific gravity, solids concentration, and water concentration, each of which will be explained below. VOC content (g / L) = Composition specific gravity x 1,000 x (100 - solid content concentration - water concentration) / 100 (1)

[0110] The specific gravity (g / mL) of the composition is a value calculated by filling a specific gravity cup having an internal volume of 100 mL with the composition at a temperature of 23°C and measuring the mass of the composition. The solid content concentration (mass %) is a value calculated by the method described above. The water concentration (mass %) is the amount of water (mass %) contained in 100 mass % of the composition, and is measured according to the Karl Fischer method using a water meter (for example, CA-310, manufactured by Nitto Seiko Analytech).

[0111] In one embodiment, the present composition is preferably a one-component composition containing a urethane resin (A), a rosin ester compound (B), an antifouling agent (C), water (D), and, if necessary, the other synthetic resin described above, and, if necessary, the other component described above.

[0112] [Uses of water-based antifouling paint compositions] Because this composition is a water-based coating composition, it has little adverse effect on the environment or the human body. By using this composition, it is possible to form an antifouling coating film that is excellent in water resistance and antifouling properties that can inhibit the attachment of aquatic organisms for a long period of time, and it is possible to form an antifouling coating film that is excellent in antifouling properties (antifouling properties at the water's edge) in the alternating wet-dry area that is the boundary between the constantly submerged and non-submerged areas.

[0113] One embodiment of the antifouling coating film of the present disclosure (hereinafter also referred to as "the present antifouling coating film") is formed from the present composition. One embodiment of the coated article of the present disclosure (hereinafter also referred to as "the present coated article") has a substrate and the present antifouling coating film provided on the surface of the substrate.

[0114] The method for producing the coated article includes a step of applying the composition to the surface of a substrate to form an antifouling coating film, specifically, a step of applying the composition to the surface of a substrate and drying to form an antifouling coating film. The application may be performed once or multiple times. Examples of application methods include dipping, brush coating, roller coating, air spraying, airless spraying, flow coating, and spin coating. Two or more of these methods may be used in combination.

[0115] The composition applied to the substrate may be dried by natural drying or by heat drying. Specifically, the composition applied to the substrate may be dried by leaving it at 5 to 40°C, preferably for about 1 to 10 days, more preferably for about 1 to 8 days, to form an antifouling coating film.

[0116] The coated article can also be produced by forming an antifouling coating film from the composition on the surface of a temporary substrate, peeling the antifouling coating film from the temporary substrate, and applying it to the substrate to be antifouled. In this case, the antifouling coating film may be applied to the substrate via an adhesive layer.

[0117] The surface of the substrate may be treated with a primer. The substrate may have a substrate body and, on the surface of the substrate body, a layer formed from various resin-based paints such as epoxy resin-based paints, vinyl resin-based paints, (meth)acrylic resin-based paints, or urethane resin-based paints. In this case, the surface of the substrate on which the present antifouling coating film is to be formed means the surface after primer treatment or the surface of the layer formed from the above-mentioned resin-based paints. Furthermore, for the purpose of repair, the present antifouling coating film may be further formed on the surface of an antifouling substrate on which the present antifouling coating film or a conventional antifouling coating film has been formed on the substrate body, such as an antifouling substrate having a deteriorated antifouling coating film on the substrate body.

[0118] The substrate is not particularly limited. The composition is preferably used to provide long-term antifouling properties to substrates in a wide range of industrial fields, such as ships. For this reason, examples of substrates include ship hull shells (steel plates, etc.), underwater structures, seawater or freshwater supply and drainage pipes in various facilities, fishing equipment, and other marine materials. Examples of ships include large steel ships such as container ships and tankers, fishing boats, FRP boats, wooden boats, yachts, motorboats, and personal watercraft. Examples of hull shells include bottom shells and outer hulls. Examples of underwater structures include oil pipelines, water supply and drainage pipes, circulating water pipes, water supply and drainage outlets in various facilities, submarine cables, seawater utilization equipment (seawater pumps, etc.), megafloats, coastal roads, undersea tunnels, port facilities, offshore wind power generation facilities, and various underwater civil engineering structures in canals or waterways. Examples of the above-mentioned facilities include factories, thermal power plants, and nuclear power plants. Examples of fishing equipment include ropes, fishing gear, fishing nets, floats, and buoys. Examples of other marine equipment include swimsuits, diver suits, underwater goggles, oxygen cylinders, and torpedoes. Among these, ship hull shells, underwater structures, fishing equipment, and water supply and drainage pipes are preferred, ship hull shells and underwater structures are more preferred, and ship hull shells are particularly preferred.

[0119] The thickness of the present antifouling coating film is not particularly limited, but is, for example, about 30 to 1000 μm. When forming the present antifouling coating film, the present composition may be applied one or more times so that the thickness of the antifouling coating film formed by one application is preferably 10 to 300 μm, more preferably 30 to 250 μm.

[0120] Compared to conventional organic solvent-based coating compositions, this composition can form an antifouling coating film having constantly submerged areas and alternating wet and dry areas, in which discoloration of the alternating wet and dry areas is suppressed. Therefore, by using this composition, it is possible to form an antifouling coating film with high designability in which discoloration is suppressed even in the alternating wet and dry areas. A constantly submerged portion is a portion that is always submerged in water in the environment in which the coated product is used, such as the bottom of a ship. An alternately wet and dry portion is a portion that is repeatedly exposed to dry and wet environments in the environment in which the coated product is used, such as the waterline portion of the hull hull near the seawater surface in the case of a ship. For example, when the substrate is a ship, the substrate has a bottom portion (corresponding to the portion that is always submerged) and a waterline portion (corresponding to the alternating wet and dry portion) that are exposed to a biological fouling environment. By using the present composition to provide an antifouling coating film on the bottom portion and the waterline portion of the substrate, discoloration of the antifouling coating film in the alternating wet and dry portion can be suppressed compared to conventional organic solvent-based paint compositions.

[0121] [Example of situation] The present disclosure relates to, for example, the following [1] to

[12] . [1] A water-based antifouling coating composition containing a urethane resin (A), a rosin ester compound (B), an antifouling agent (C), and water (D), wherein the acid value of the solid content of the coating composition is 25 mgKOH / g or less. [2] The water-based antifouling coating composition according to [1] above, wherein the content of the urethane resin (A) is 3 mass % or more based on 100 mass % of the solid content of the coating composition. [3] The aqueous antifouling coating composition according to [1] or [2], wherein, based on 100% by mass of the solid content of the coating composition, the content of the urethane resin (A) is 3 to 30% by mass, the content of the rosin ester compound (B) is 3 to 40% by mass, and the content of the antifouling agent (C) is 0.01 to 80% by mass. [4] The aqueous antifouling coating composition according to any one of the above [1] to [3], wherein the urethane resin (A) has a poly(oxyalkylene) structure. [5] The aqueous antifouling coating composition according to [4] above, wherein the urethane resin (A) further has a carbonate group. [6] The aqueous antifouling coating composition according to any one of [1] to [5] above, wherein the rosin ester compound (B) has an acid value of 20 mgKOH / g or less. [7] The aqueous antifouling coating composition according to [6] above, wherein the rosin ester compound (B) is an ester of rosin or a derivative thereof with a trihydric or higher polyhydric alcohol. [8] The aqueous antifouling coating composition according to any one of [1] to [7], wherein the ratio of the content of the rosin ester compound (B) to the content of the urethane resin (A) in the coating composition (content of (B) / content of (A)) is 0.3 to 4.0 by mass. [9] The aqueous antifouling coating composition according to any one of [1] to [8] above, wherein the content of the water (D) in the coating composition is 20 to 60 mass %.

[10] An antifouling coating film formed from the aqueous antifouling coating composition according to any one of [1] to [9] above.

[11] A coated article having a substrate and the antifouling coating film according to

[10] provided on the surface of the substrate.

[12] A method for producing a coated article having a substrate and an antifouling coating film, comprising the step of applying the aqueous antifouling coating composition according to any one of [1] to [9] above to the surface of the substrate to form an antifouling coating film. [Example]

[0122] The present composition will be described in more detail below based on examples, but the present composition is not limited to the following examples. Measurement methods for physical properties other than those described below are as described above. In the following examples and comparative examples, "parts" refers to "parts by mass."

[0123] [Weight average molecular weight (Mw)] The weight average molecular weight (Mw) of the rosin-based compound was measured by gel permeation chromatography (GPC) under the following measurement conditions. (Measurement conditions) Apparatus: Alliance 2695 (Waters) Column: One "TSKgel SuperH4000" and two "TSKgel SuperH2000" columns connected together (both manufactured by Tosoh, inner diameter 6 mm x length 15 cm) Eluent: 99% tetrahydrofuran (containing BHT) ·Flow rate: 0.6ml / min Detector: "RI-104" (Shodex) Column thermostat temperature: 40℃ Standard material: Standard polystyrene Sample preparation: Weigh the sample into a sample tube. Tetrahydrofuran was added to dilute the solution approximately 100 times.

[0124] [raw materials] <Urethane resin (A) emulsion> Urethane resin emulsion (A1) Polycarbonate-based HMDI polyurethane emulsion, Solid content concentration: 30% by mass, moisture content: 68% by mass, pH: 7.7, solid content acid value: 1.1mgKOH / g, Z average particle size: 150nm, Glass transition temperature: 41°C, Molecular structure (molar ratio) of urethane resin by NMR analysis ·1,6-Hexanediol derived structure: 39 Polyethylene glycol structure: 21 (-(OCH2CH2)- equivalent) Carbonate groups: 32 HMDI derived structures: 8

[0125] Urethane resin emulsion (A2) Butanediol modified IPDI polyurethane emulsion, Solid content concentration: 55% by mass, moisture content: 44% by mass, pH: 9.5, solid content acid value: 5.5mgKOH / g, Z average particle size: 362nm, Glass transition temperature: 2.7℃, Molecular structure (molar ratio) of urethane resin by NMR analysis Polytetramethylene glycol structure: 91 (-(OCH2CH2CH2CH2)- equivalent) IPDI-derived structure: 7 Carbonate groups: 2

[0126] Urethane resin emulsion (A3) Polyester modified IPDI polyurethane emulsion, Solid content concentration: 31% by mass, moisture content: 67% by mass, pH: 9.3, solid content acid value: 26.6mgKOH / g, Z average particle size: 52nm, Glass transition temperature: 27°C, Molecular structure (molar ratio) of urethane resin by NMR analysis ·1,6-Hexanediol derived structure: 41 TMP-derived structure: 6 Sebacic acid derived structure: 42 IPDI-derived structure: 9 Carbonate groups: 2

[0127] The water content was measured by the Karl Fischer method. NMR analysis was performed using an AVANCE NEO 400 (Bruker Japan) measuring device. 13 C-NMR was performed under the conditions of frequency: 100.6 MHz, solvent: chloroform-d.

[0128] <Acrylic resin emulsion> PRIMAL TX-100 Dow Chemical's water-based emulsion of acrylic resin (self-crosslinking type) Solid concentration: 46% by mass, pH: 7.7, solid acid value: 15.7mgKOH / g, Glass transition temperature: 28℃

[0129] <Rosin-based compound emulsion> Harrie Star SK-218NS Harima Chemicals, rosin ester (ester of rosin or its derivative with a trihydric or higher polyhydric alcohol) aqueous emulsion (B1), solids concentration: 50% by mass, pH: 8.2, solid acid value: 13.6 mg KOH / g, Mw: 1,200 Harsize NES-500 Harima Chemicals, rosin aqueous emulsion (cB1), solids concentration: 50% by mass, pH: 5.7, solid acid value: 246 mg KOH / g, Mw: 310

[0130] The ingredients used other than those mentioned above are listed in Table 1. [Table 1]

[0131] [Preparation of antifouling coating composition] Example 1: Water-based antifouling paint composition A water-based antifouling paint composition was prepared as follows. 4.8 parts deionized water, 3.0 parts DISPERBYK-190 (dispersant), and 0.05 parts Natrosol Plus 330PA (thickener 1) were added to a container and mixed using a paint shaker until each component was uniformly dispersed or dissolved in the water. 3.0 parts Mica Powder 325 mesh (extender), 39.0 parts LOLO TINT LM (stain-repellent (C)), 4.0 parts Talc F-2 (extender), 3.0 parts COPPER OMADINE POWDER (stain-repellent (C)), 1.5 parts Carbon Black MA-100 (color pigment), 0.1 parts BYK-018 (defoamer 1), and 100 parts glass beads were then added to the container and stirred using a paint shaker for 1 hour to disperse the components and obtain a mixture. After dispersion, the glass beads were removed from the mixture using a filter net (opening: 80 mesh). To the filtrate, 18.6 parts of a polycarbonate-based HMDI polyurethane emulsion (A1), 17.0 parts of Hariestar SK-218NS (aqueous emulsion of rosin ester (B1)), 1.9 parts of DOWANOL DPnB Glycol Ether (coal-forming agent 1), 1.9 parts of DOWANOL DPM Glycol Ether (coal-forming agent 2), 0.2 parts of Selektope (antifouling agent (C)), 0.8 parts of COAPUR XS 83 (thickener 2), 0.8 parts of butyl cellosolve (coal-forming agent 3), and 0.3 parts of BYK-093 (defoaming agent 2) were added while rotating the disperser, and the mixture was dispersed for 20 minutes to obtain an antifouling coating composition.

[0132] [Example 2 and Comparative Examples 1 to 3: Water-based antifouling coating compositions] Water-based antifouling coating compositions were prepared in the same manner as in Example 1, except that the types and amounts of each component were changed as shown in Table 2. The amounts in Table 2 are in parts by mass.

[0133] Comparative Example 4: Organic Solvent-Based Antifouling Coating Composition A composition was prepared in which the titanium oxide in composition x-19 described in Table 4 of paragraph

[0133] of WO 2018 / 221641 was replaced with black iron oxide (KN-320, manufactured by Toda Kogyo Kogyo Co., Ltd.).

[0134] [Evaluation of the physical properties of antifouling paint compositions] <Acid value> Sample preparation (in the case of water-based antifouling paint compositions: ethanol extraction treatment) Approximately 10 g of each of the coating compositions of Examples 1-2 and Comparative Examples 1-3 was placed in a 50 mL polypropylene (PP) tube for centrifugation and weighed. Approximately 20 mL of ethanol was added to balance the amount, and the contents of the PP tube were stirred with a vortex mixer until homogenous. Next, the tube was centrifuged at 0°C, 12,000 rpm, and for 30 minutes, and the supernatant was removed and transferred to another container.

[0135] Sample preparation (xylene extraction treatment for organic solvent-based antifouling paint compositions) Approximately 10 g of the coating composition of Comparative Example 4 was placed in a 50 mL centrifuge PP tube and weighed. Approximately 20 mL of xylene was added to balance the contents, and the contents of the PP tube were stirred with a vortex mixer until homogenous. Next, the tube was centrifuged at 0°C, 12,000 rpm, and 30 minutes, and the supernatant was removed and transferred to another container. Approximately 20 mL of xylene was added to the PP tube containing the residue, and the contents of the PP tube were thoroughly stirred with a vortex mixer. Next, the tube was centrifuged at 0°C, 12,000 rpm, and 30 minutes, and the supernatant was removed and added to the same container containing the first supernatant.

[0136] Acid value measurement A 12 mL sample (here, the supernatant in the container) was placed in a disposable cup, its mass was weighed, and the sample volume was recorded. 50 mL of a mixed solution of toluene:ethanol = 8:2 (volume ratio) was added to the cup. The resulting solution was subjected to potentiometric titration at 25°C using a 0.1 mol / L KOH-ethanol solution, and the titration volume was recorded. The acid value of the solution was calculated based on the following formula: Solution acid value (mgKOH / g)=(56.11×0.1×F×V) / M 56.11: Molar mass of KOH 0.1: Concentration of KOH-ethanol solution [mol / L] F: Factor of KOH-ethanol solution V: Titration volume minus blank value [mL] M: Sample amount [g]

[0137] ·Heating residue measurement A flat-bottom dish labeled with the sample name was weighed, and approximately 1.0 g of the sample (here, the supernatant) was weighed out (n=3). After drying at 125°C for 1 hour, the sample was cooled to room temperature and then weighed. The solids concentration in the supernatant was calculated from the obtained heating residue, and the solids acid value of each coating composition was obtained by dividing the solution acid value by the solids concentration.

[0138] <Static stain resistance test before or after dynamic curing> An epoxy anticorrosion paint (trade name "Banno 1500", manufactured by Chugoku Toryo Co., Ltd.) was applied to a sandblasted steel plate (length: 300 mm, width: 100 mm, thickness: 2.3 mm) to a dry film thickness of 150 μm and dried to form a cured coating film. Next, an epoxy binder paint (trade name "CMP AC-EP", manufactured by Chugoku Toryo Co., Ltd.) was applied to the cured coating film to a dry film thickness of 100 μm and dried at 23°C for 24 hours to form a dry coating film.

[0139] Next, each of the antifouling coating compositions of Examples and Comparative Examples listed in Table 2 was applied to the surface of the dried coating film of the above epoxy binder paint using an applicator to a dry film thickness of 200 μm, and the antifouling coating film was formed by drying at 23° C. for 7 days to prepare a test panel. This test panel was placed on the inner surface of a cylinder in a water current generating device and cured (dynamic curing) for 3 months in artificial seawater under a water current of 40° C. and 15 knots.

[0140] The above test panels, which had not been subjected to dynamic curing, were suspended and immersed in the Seto Inland Sea off the coast of Hatsukaichi City, Hiroshima Prefecture, with the length of the test panel aligned with the direction of gravity and the top 0.1 m of the test panel exposed above the water surface (semi-submerged), and then left to stand. Every month from the start of immersion, the area (%) of the antifouling coating film on which aquatic organisms had adhered, relative to the total area of ​​the antifouling coating film on the test panel (hereinafter also referred to as "adhesion area A"), was investigated for four months. The static antifouling properties were evaluated visually based on the following evaluation criteria.

[0141] (Evaluation criteria) 5: The adhesion area A is less than 5%. 4: The adhesion area A is 5% or more and less than 20%. 3: The adhesion area A is 20% or more and less than 40%. 2: The adhesion area A is 40% or more and less than 60%. 1: The adhesion area A is 60% or more.

[0142] After dynamic curing, the test panels were suspended and immersed in the Seto Inland Sea off the coast of Hatsukaichi City, Hiroshima Prefecture, with the length of the test panel aligned with the direction of gravity and the top 0.1 m of the test panel exposed above the water surface (semi-submerged), and left to stand. Four months after the start of immersion, the static antifouling properties (static antifouling properties after dynamic curing) were evaluated visually based on the following evaluation criteria, with the area (%) of the antifouling coating film on which aquatic organisms had adhered (hereinafter also referred to as "adhesion area B"), assuming the total area of ​​the antifouling coating film on the test panel to be 100%.

[0143] (Evaluation criteria) 5: The adhesion area B is less than 5%. 4: The adhesion area B is 5% or more and less than 20%. 3: The adhesion area B is 20% or more and less than 40%. 2: The adhesion area B is 40% or more and less than 60%. 1: The adhesion area B is 60% or more.

[0144] <Evaluation of discoloration resistance in alternating wet and dry areas> The above test plate, which had not been subjected to dynamic curing, was suspended and immersed in the Seto Inland Sea off the coast of Hatsukaichi City, Hiroshima Prefecture, so that the length direction of the test plate was aligned with the direction of gravity and the top 0.1 m of the test plate was exposed above the water surface (semi-submerged), and then left to stand. Before the immersion, the top 0.1 m of the exposed area above the water surface (alternating wet and dry areas) was measured using a spectro 2 guide (spectrophotometer / colorimeter, manufactured by BYK-Gardner) under the conditions of a light source of D65 and a viewing angle of 10°, using CIE L * a * b * The CIELAB (CiE Lab) was measured. After the immersion for one year, the same measurements were made on the wet and dry alternating sections of the test panels. The ΔE (color difference) of the wet and dry alternating sections before and after the immersion was calculated using the following formula. Each measurement was made three times, and the average value was used for evaluation. ΔE={(L * 1-L * 0) 2 +(a * 1-a * 0) 2 +(b * 1-b * 0) 2} 1 / 2 L * 1, a * 1 and b * 1 is the L of the alternating wet and dry parts of the coating after immersion for one year * , a * and b * L * 0, a * 0 and b * 0 is the L of the alternating wet and dry parts of the coating film before immersion. * , a * and b * respectively.

[0145] <Water resistance test of coating film> An epoxy anticorrosion paint (trade name "Banno 1500", manufactured by Chugoku Toryo Co., Ltd.) was applied to a sandblasted steel plate (length: 150 mm, width: 70 mm, thickness: 2.3 mm) to a dry film thickness of 150 μm and dried to form a cured coating film. Next, an epoxy binder paint (trade name "CMP AC-EP", manufactured by Chugoku Toryo Co., Ltd.) was applied to the cured coating film to a dry film thickness of 100 μm and dried at 23°C for 24 hours to form a dry coating film. Next, each of the antifouling coating compositions of the Examples and Comparative Examples listed in Table 2 was applied to the surface of the dried coating film of the above epoxy binder paint using an applicator so that the dry film thickness was 300 μm, and the coating was dried at 23°C for 7 days to form an antifouling coating film, and a test panel was prepared. The test plate with the antifouling coating film was immersed in artificial seawater at 50°C, and after 6 months from the start of immersion, the crack resistance of the coating film was evaluated based on the following evaluation criteria.

[0146] (Evaluation criteria) AA: No cracks were visible even when magnified 100 times using an optical microscope (High Speed ​​Microscope VW-9000 (manufactured by KEYENCE), lens: VW-600C). BB: Cracks can be recognized visually or when magnified 100 times using the optical microscope mentioned above.

[0147] [Table 2]

Claims

1. urethane resin (A), a rosin ester compound (B), an antifouling agent (C), and Water (D) A water-based antifouling coating composition comprising: the urethane resin (A) has a poly(oxyalkylene) structure, The acid value of the solid content of the coating composition is 25 mg KOH / g or less. A water-based antifouling paint composition.

2. In 100% by mass of the solid content of the coating composition, The content of the urethane resin (A) is 3% by mass or more. The water-based antifouling coating composition according to claim 1.

3. In 100% by mass of the solid content of the coating composition, The content of the urethane resin (A) is 3 to 30 mass %, the content of the rosin ester compound (B) is 3 to 40 mass %, The content of the antifouling agent (C) is 0.01 to 80 mass%. The water-based antifouling coating composition according to claim 1.

4. The aqueous antifouling coating composition according to claim 1, wherein the urethane resin (A) further has a carbonate group.

5. 2. The aqueous antifouling coating composition according to claim 1, wherein the rosin ester compound (B) has an acid value of 20 mg KOH / g or less.

6. 6. The aqueous antifouling coating composition according to claim 5, wherein the rosin ester compound (B) is an ester of rosin or a derivative thereof with a trihydric or higher polyhydric alcohol.

7. 2. The aqueous antifouling coating composition according to claim 1, wherein the ratio of the content of the rosin ester compound (B) to the content of the urethane resin (A) in the coating composition (content of (B) / content of (A)) is 0.3 to 4.0 on a mass basis.

8. 2. The aqueous antifouling coating composition according to claim 1, wherein the content of said water (D) in said coating composition is 20 to 60 mass %.

9. An antifouling coating film formed from the aqueous antifouling coating composition according to any one of claims 1 to 8.

10. A substrate; The antifouling coating film according to claim 9 provided on the surface of the substrate; A painted product having the above characteristics.

11. A method for producing a coated article having a substrate and an antifouling coating film, comprising a step of applying the aqueous antifouling coating composition according to any one of claims 1 to 8 to the surface of the substrate to form an antifouling coating film.

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