Underwater Anti-fouling coating material composition

Abstract

One embodiment of the present invention relates to: an underwater anti-fouling coating material composition; an anti-fouling coating film; a substrate having an anti-fouling coating film and a method for producing same; and a substrate anti-fouling method. The underwater anti-fouling coating material composition contains: a hydrolyzable (co)polymer (A) having a constituent unit derived from a hydrolyzable group-containing monomer; a rosin-based compound (B); and an anti-fouling agent. The rosin-based compound (B) contains a rosin-based compound monomer (B1) and a rosin-based compound oligomer (B2). The content of the oligomer (B2) is 0.07-5 parts by mass relative to 1 part by mass of the monomer (B1). The total content of the (co)polymer (A) and the rosin-based compound (B) is 5-40 mass% relative to 100 mass% of solid content in the underwater anti-fouling coating material composition.

Description

Underwater antifouling paint composition

[0001] One embodiment of the present invention relates to an underwater antifouling paint composition, an antifouling coating film, a substrate with an antifouling coating film or a method for producing the same, or a method for antifouling a substrate.

[0002] In order to prevent underwater structures such as the bottom of a ship from suffering economic losses due to increased propulsion resistance caused by the adhesion of aquatic organisms and damage caused by erosion by aquatic organisms, a method of antifouling the underwater structures is generally adopted in which an antifouling coating film is formed by applying an antifouling coating composition to the surface of the underwater structures.

[0003] A widely used antifouling method involves forming an antifouling coating film containing a hydrolyzable (co)polymer on the surface of a substrate. In water (seawater), the antifouling coating film becomes hydrophilic as the hydrolysis of the (co)polymer progresses, and the hydrophilized portion is consumed by water flow or the like (the antifouling coating film is renewed), thereby exhibiting antifouling properties.

[0004] As an example of an antifouling coating composition that forms an antifouling coating film that exhibits antifouling properties as the antifouling coating film is worn away (the antifouling coating film is renewed), Patent Document 1 describes an antifouling coating composition that contains a rosin compound and an organic silyl ester group-containing polymer and is capable of forming an antifouling coating film whose coating film wear rate does not change over time and is at least a certain rate.

[0005] Japanese Patent Application Publication No. 10-030071

[0006]

[0003] Antifouling coating films formed from antifouling coating compositions containing organic silyl ester group-containing polymers as described in Patent Document 1 exhibit excellent antifouling properties against aquatic (marine) organisms, but it has been found that the rate of wear of the coating film changes significantly when the temperature of the environment (e.g., seawater) in which the antifouling coating film is placed changes. For example, it has been found that in ships formed with the conventional antifouling coating film, depending on the sea area in which they sail, the wear rate of the antifouling coating film is lower than the expected wear rate (design wear rate) of the antifouling coating film in low-temperature sea areas, resulting in insufficient antifouling properties, and in high-temperature sea areas, the wear rate of the antifouling coating film is higher than the design wear rate, resulting in early disappearance of the antifouling coating film and making it impossible to prevent fouling of the substrate (ship).

[0007] Furthermore, for example, the surface of a ship may experience increased surface roughness or damage to anticorrosion coatings and other coatings formed underneath the antifouling coating due to collisions with the sea surface or floating objects in the sea, damage from blocks during shipbuilding, or damage from fenders installed on quays. In particular, during shipbuilding, ships are sometimes temporarily placed on blocks, and the antifouling coating in contact with the blocks is damaged, leaving traces of the blocks or causing the periphery to swell. Such damaged antifouling coatings require repair, etc., and therefore, in order to reduce the time and cost required for such repairs, etc., antifouling coatings are required to have damage resistance (block resistance).

[0008] One embodiment of the present invention provides an underwater antifouling coating composition that is excellent in block resistance and antifouling properties, has little temperature dependency of the wear rate of the antifouling coating film (hereinafter also referred to as "temperature dependency of wear rate"), and is capable of forming an antifouling coating film with a stable wear rate.

[0009] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by the following configuration examples, and have thus completed the present invention.

[0010] [1] An underwater antifouling coating composition comprising a hydrolyzable (co)polymer (A) having structural units derived from a hydrolyzable group-containing monomer, a rosin compound (B), and an antifouling agent (C), wherein the rosin compound (B) comprises a rosin compound monomer (B1) and a rosin compound multimer (B2), the content of the multimer (B2) per part by mass of the content of the monomer (B1) is 0.07 to 5 parts by mass, and the total content of the (co)polymer (A) and the rosin compound (B) per 100% by mass of the solids content of the underwater antifouling coating composition is 5 to 40% by mass.

[0011] [2] The underwater antifouling coating composition according to [1], wherein the (co)polymer (A) contains a structural unit derived from a silyl ester group-containing monomer (a1) represented by the following formula (1): X-SiR 1 R 2 R 3 ...(1) [In formula (1), X is an ethylenically unsaturated acyloxy group, and R 1 ~R 3 are each independently a linear or branched alkyl group having 1 to 20 carbon atoms, an alicyclic alkyl group having 3 to 10 carbon atoms, or an aromatic group having 6 to 20 carbon atoms.

[0012] [3] The R 1 ~R 3 [4] The underwater antifouling coating composition according to [2] or [3], wherein the silyl ester group-containing monomer (a1) is triisopropylsilyl methacrylate.

[0013] [5] The underwater antifouling coating composition according to any one of [1] to [4], wherein the content of the rosin compound (B) is 0.1 to 2 parts by mass per part by mass of the (co)polymer (A). [6] The underwater antifouling coating composition according to any one of [1] to [5], wherein the content of the multimer (B2) is 0.01 to 1 part by mass per part by mass of the (co)polymer (A).

[0014] [7] The underwater antifouling coating composition according to any one of [1] to [6], wherein the antifouling agent (C) contains cuprous oxide, and the content of the cuprous oxide is 30 to 80 mass% relative to 100 mass% of the solids content of the underwater antifouling coating composition.

[0015] [8] The underwater antifouling coating composition according to any one of [1] to [7], further containing a pigment (D).

[0016] [9] An antifouling coating film formed from the underwater antifouling coating composition according to any one of [1] to [8].

[0017]

[10] A substrate with an antifouling coating film, comprising a substrate and the antifouling coating film according to [9].

[11] A method for producing a substrate with an antifouling coating film, comprising the steps of applying the underwater antifouling paint composition according to any one of [1] to [8] to at least a part of the substrate and then drying the composition.

[0018]

[12] A method for antifouling a substrate, comprising the step of forming the antifouling coating film according to [9] on at least a part of the substrate.

[0019] According to one embodiment of the present invention, it is possible to form an antifouling coating film that has excellent resistance to wood damage (damage resistance) and antifouling properties, has little temperature dependency on wear rate, and has a stable wear rate. Therefore, according to one embodiment of the present invention, it is possible to form an antifouling coating film that is less susceptible to damage, thereby reducing the time and cost required for repairs that would be necessary if damage were to occur, and further, it is possible to exhibit the expected antifouling properties even if the seawater temperature changes due to, for example, changes in the navigation area.

[0020] FIG. 1 is a schematic diagram showing the evaluation criteria in the block durability test in the examples.

[0021] <Underwater Antifouling Coating Composition> An underwater antifouling coating composition according to one embodiment of the present invention (hereinafter also referred to as "the composition") comprises a hydrolyzable (co)polymer (A) having structural units derived from a hydrolyzable group-containing monomer, a rosin-based compound (B), and an antifouling agent (C), wherein the rosin-based compound (B) comprises a rosin-based compound monomer (B1) and a rosin-based compound multimer (B2), the content of the multimer (B2) per part by mass of the content of the monomer (B1) is 0.07 to 5 parts by mass, and the total content of the (co)polymer (A) and the rosin-based compound (B) is 5 to 40% by mass relative to 100% by mass of the solids content of the composition.

[0022] <Hydrolyzable (co)polymer (A)> The hydrolyzable (co)polymer (A) is not particularly limited as long as it is a (co)polymer having a structural unit derived from a hydrolyzable group-containing monomer. The (co)polymer (A) used in the present composition may be one type or two or more types.

[0023] In the present invention, the term "(co)polymer having a structural unit derived from the monomer Z" means a polymer and / or copolymer obtained by a polymerization reaction or a chain transfer reaction using the monomer Z.

[0024] The weight-average molecular weight (Mw) of the (co)polymer (A) is preferably 3,000 to 70,000, more preferably 10,000 to 50,000, from the viewpoints of easily obtaining a present composition having excellent coating workability and easily forming an antifouling coating film having excellent coating film strength. The molecular weight distribution (Mw / Mn) of the (co)polymer (A) is not particularly limited, but from the viewpoints of easily obtaining a uniform present composition, it is preferably 20 or less, more preferably 6 or less, and preferably 1 or more, more preferably 2 or more. The Mw and number-average molecular weight (Mn) of the (co)polymer (A) can be measured by the method described in the Examples.

[0025] The content of the (co)polymer (A) in the present composition is preferably 4 to 35 mass%, more preferably 8 to 30 mass%, and even more preferably 12 to 25 mass%, based on 100 mass% of the solids content of the present composition. When the content of the (co)polymer (A) is within this range, an antifouling coating film having excellent antifouling properties and a stable coating film wear rate can be easily formed.

[0026] The "solid content" of the present composition refers to the components other than the solvent in the present composition, and is the solid content obtained by drying the present composition in a hot air dryer at 105°C for 1 hour.

[0027] [Structural Unit Derived from Silyl Ester Group-Containing Monomer (a1)] The (co)polymer (A) preferably contains a structural unit derived from a silyl ester group-containing monomer (a1) represented by the following formula (1), from the viewpoint of being able to easily form an antifouling coating film that has excellent antifouling properties against aquatic (marine) organisms. When the (co)polymer (A) contains a structural unit derived from the monomer (a1), the structural unit contained in the (co)polymer (A) may be of one type or of two or more types.

[0028] X-SiR 1 R 2 R 3 ...(1) [In formula (1), X is an ethylenically unsaturated acyloxy group, and R 1 ~R 3 are each independently a linear or branched alkyl group having 1 to 20 carbon atoms, an alicyclic alkyl group having 3 to 10 carbon atoms, or an aromatic group having 6 to 20 carbon atoms.

[0029] Examples of X include an acryloyloxy group, a methacryloyloxy group, a ((meth)acryloyloxy)alkylcarboxy group, a maleinoyloxy group, a fumaroyloxy group, an itaconoyloxy group, and a citraconoyloxy group. Of these, an acryloyloxy group and a methacryloyloxy group are preferred, and a methacryloyloxy group is more preferred from the viewpoint that an antifouling coating film having excellent long-term antifouling properties and water resistance can be easily formed.

[0030] In this specification, "(meth)acryloyl", "(meth)acrylate", "(meth)acrylic acid", and "(meth)acrylic" mean "acryloyl and / or methacryloyl", "acrylate and / or methacrylate", "acrylic acid and / or methacrylic acid", and "acrylic and / or methacrylic", respectively.

[0031] The R 1 ~R 3 The number of carbon atoms in the alkyl group in the R is preferably 1 to 12, more preferably 1 to 8, and even more preferably 1 to 4. 1 ~R 3 The number of carbon atoms in the alicyclic alkyl group in R is preferably 3 to 8, and more preferably 4 to 7. 1 ~R 3 The aryl group in the formula (I) preferably has 6 to 14 carbon atoms, and more preferably 6 to 10 carbon atoms.

[0032] It has moderate hydrolysis property and can easily form an antifouling coating film with excellent long-term antifouling properties and water resistance. 1 ~R 3 are each independently preferably a methyl group, an ethyl group, an isopropyl group, an n-propyl group, a sec-butyl group, an n-butyl group, or a phenyl group, and R 1 ~R 3 More preferably, all of R are an isopropyl group, an n-propyl group, a sec-butyl group, or an n-butyl group, 1 ~R 3 It is more preferable that all of the groups are isopropyl groups.

[0033] Suitable examples of the monomer (a1) include trialkylsilyl (meth)acrylate, alkyldiarylsilyl (meth)acrylate, aryldialkylsilyl (meth)acrylate, maleic acid silyl ester monomer, and fumaric acid silyl ester monomer. Among these, trialkylsilyl (meth)acrylate is more preferred.

[0034] Examples of the trialkylsilyl (meth)acrylate include trimethylsilyl (meth)acrylate, triethylsilyl (meth)acrylate, triisopropylsilyl (meth)acrylate, tri-n-propylsilyl (meth)acrylate, tri-sec-butylsilyl (meth)acrylate, and tri-n-butylsilyl (meth)acrylate. Among these, triisopropylsilyl (meth)acrylate is more preferred, and triisopropylsilyl methacrylate is particularly preferred from the viewpoint of being able to easily form an antifouling coating film having excellent internal water resistance.

[0035] Examples of the alkyldiarylsilyl(meth)acrylate include methyldiphenylsilyl(meth)acrylate, ethyldiphenylsilyl(meth)acrylate, isopropyldiphenylsilyl(meth)acrylate, n-propyldiphenylsilyl(meth)acrylate, sec-butyldiphenylsilyl(meth)acrylate, and n-butyldiphenylsilyl(meth)acrylate.

[0036] Examples of the aryldialkylsilyl(meth)acrylate include phenyldimethylsilyl(meth)acrylate, phenyldiethylsilyl(meth)acrylate, phenyldiisopropylsilyl(meth)acrylate, phenyl-di-n-propylsilyl(meth)acrylate, phenyl-di-sec-butylsilyl(meth)acrylate, and phenyl-di-n-butylsilyl(meth)acrylate.

[0037] Examples of the silyl ester monomer of maleic acid include triethylsilylethyl maleate, tri-n-propylsilyl n-propyl maleate, triisopropylsilylmethyl maleate, tri-n-butylsilyl n-butyl maleate, and tri-n-hexylsilyl n-hexyl maleate.

[0038] Examples of the silyl ester monomer of fumaric acid include triethylsilylethyl fumarate, tri-n-propylsilyl n-propyl fumarate, triisopropylsilylmethyl fumarate, tri-n-butylsilyl n-butyl fumarate, and tri-n-hexylsilyl n-hexyl fumarate.

[0039] Furthermore, upon hydrolysis, the structural units derived from the monomer (a1) will have the same structure as the structural units derived from X-H (wherein X has the same meaning as X in formula (1)). Therefore, in the (co)polymer (A), some of the structural units derived from the monomer (a1) may, upon hydrolysis, have the same structure as the structural units derived from X-H. Furthermore, the structural units produced by hydrolysis may react with other components, such as metal oxides, that may be contained in the composition to further form metal esters.

[0040] When the (co)polymer (A) has a structural unit derived from the monomer (a1), the content of the structural unit is preferably 10 to 90% by mass, more preferably 30 to 80% by mass, even more preferably 40 to 80% by mass, and particularly preferably 40 to 70% by mass, relative to 100% by mass of all structural units of the (co)polymer (A), from the viewpoint of being able to easily form an antifouling coating film that is excellent in water resistance and has an appropriate hydrolysis rate.

[0041] The content (% by mass) of the structural units derived from each monomer in the (co)polymer (A) can be calculated from the charged amount (% by mass) of each monomer used in synthesizing the (co)polymer (A). Alternatively, the content of the structural units derived from each monomer may be determined by analyzing the obtained (co)polymer (A) or the (co)polymer (A) isolated from the present composition by mass spectrometry, IR (infrared spectroscopy), NMR (nuclear magnetic resonance spectroscopy), ICP-MS (inductively coupled plasma mass spectrometry), ICP-AES (inductively coupled plasma atomic emission spectrometry), or the like.

[0042] [Structural Units Derived from Other Monomers (a2)] The (co)polymer (A) may contain structural units derived from other monomers (a2) besides the monomer (a1), and preferably contains such structural units. The other monomers (a2) are monomers copolymerizable with the monomer (a1). When the (co)polymer (A) contains structural units derived from the monomer (a2), the structural units contained in the (co)polymer (A) may be of one type or two or more types.

[0043] Examples of the other monomer (a2) include organosiloxane-containing monomers (a21), alkoxyalkyl (meth)acrylates or aryloxyalkyl (meth)acrylates (a22), alkyl (meth)acrylates or aryl (meth)acrylates (a23), hydroxyalkyl (meth)acrylates (a24), glycidyl (meth)acrylates (a25), unsaturated carboxylic acid compounds (a26), metal ester group-containing unsaturated monomers (a27), and other vinyl compounds (a28).

[0044] Among these, the other monomer (a2) preferably contains an organosiloxane-containing monomer (a21) and / or an alkoxyalkyl (meth)acrylate or aryloxyalkyl (meth)acrylate (a22) from the viewpoint of being able to easily form an antifouling coating film having excellent antifouling properties, and preferably contains an alkyl (meth)acrylate or aryl (meth)acrylate (a23) from the viewpoint of being able to easily form an antifouling coating film having excellent coating film strength, and preferably contains an unsaturated carboxylic acid compound (a26) from the viewpoint of being able to easily form an antifouling coating film having excellent retention of aesthetics (gloss, appearance, etc.) over time and having excellent crack resistance after immersion in water, and

[0045] When the (co)polymer (A) has a structural unit derived from the monomer (a2), the content of the structural unit is preferably 10 to 90% by mass, more preferably 20 to 70% by mass, even more preferably 20 to 60% by mass, and particularly preferably 30 to 60% by mass, relative to 100% by mass of all structural units of the (co)polymer (A), from the viewpoint that an antifouling coating film having an appropriate hydrolysis rate can be easily formed, etc.

[0046] Organosiloxane-Containing Monomer (a21) The (co)polymer (A) may contain a structural unit derived from an organosiloxane-containing monomer (a21). When the (co)polymer (A) contains a structural unit derived from the monomer (a21), the structural unit contained in the (co)polymer (A) may be of one type or of two or more types.

[0047] Examples of the organosiloxane-containing monomer (a21) include compounds having a structure represented by the following formula (II).

[0048] [In formula (II), R 11 ~R 13 each independently represents a monovalent hydrocarbon group, each X independently represents a (meth)acryloyloxyalkyl group or a mercaptoalkyl group, each m and n independently represents 0 or more, each p and q independently represents 0 or 1, and n + p + q is 1 or more.

[0049] In this specification, when two or more different repeating units are listed in parallel between brackets [ ], this means that these repeating units may be repeated in any state and order, such as random, alternating, or block. That is, for example, in the formula -[Y3-Z3]- (where Y and Z represent repeating units), the repeating units may be random, such as -YYZYZZ-, alternating, such as -YZYZYZ-, or block, such as -YYYZZZ- or -ZZZYYY-.

[0050] The R 11 ~R 13 Examples of the monovalent hydrocarbon group in R 1 ~R 3From the viewpoint of ease of polymerization and the like, an alkyl group is preferable, an alkyl group having 1 to 6 carbon atoms is more preferable, an alkyl group having 1 to 4 carbon atoms is still more preferable, and a methyl group, an ethyl group, a propyl group, or a butyl group is particularly preferable.

[0051] X in formula (II) is preferably a (meth)acryloyloxyalkyl group from the viewpoint that uniform (co)polymerization can be easily performed, and is preferably a mercaptoalkyl group from the viewpoint that a (co)polymer (A) having low viscosity and excellent handleability can be easily obtained.

[0052] The (meth)acryloyloxyalkyl group for X in formula (II) is a group represented by the following formula (III).

[0053] [In formula (III), R 21 represents a hydrogen atom or a methyl group, and R 22 represents an alkylene group, and * represents the bonding position of the (meth)acryloyloxyalkyl group to Si.

[0054] The R 22 The alkylene group in may be linear or branched, and the number of carbon atoms in the alkylene group is preferably 1 to 12, more preferably 2 to 6, and even more preferably 2 to 4, from the viewpoint of reactivity and the like.

[0055] The mercaptoalkyl group for X in formula (II) is a group represented by the following formula (IV).

[0056] [In formula (IV), R 23 represents an alkylene group, and * represents the bonding position of the mercaptoalkyl group to Si.]

[0057] The R 23 The alkylene group in may be linear or branched, and the number of carbon atoms in the alkylene group is preferably 1 to 12, more preferably 2 to 6, and even more preferably 2 to 4, from the viewpoint of reactivity and the like.

[0058] Examples of X in formula (II) include a 2-(meth)acryloyloxyethyl group, a 3-(meth)acryloyloxypropyl group, a 4-(meth)acryloyloxybutyl group, a mercaptomethyl group, a 2-mercaptoethyl group, a 2-mercaptopropyl group, a 3-mercaptopropyl group, and a 4-mercaptobutyl group.

[0059] In formula (II), m and n are each (SiR 12 2O) and (SiXR 13 In formula (II), m+n means the average number of moles of the polyorganosiloxane moiety added. In formula (II), m+n is preferably 2 or more. That is, the compound represented by formula (II) preferably has a polyorganosiloxane moiety.

[0060] One form of (co)polymer (A) preferably has a structural unit derived from compound (a211) of formula (II) in which n is 0, p is 1, and q is 0. The present composition containing (co)polymer (A) having a structural unit derived from such compound (a211) is preferred in that it can easily form an antifouling coating film with particularly excellent antifouling properties. In the compound (a211), m is preferably 3 to 200, more preferably 5 to 70, from the viewpoint of ease of polymerization, etc.

[0061] The compound (a211) may be a commercially available product, such as FM-0711 (single-terminal methacryloyloxyalkyl-modified organopolysiloxane, number average molecular weight Mn=1,000), FM-0721 (single-terminal methacryloyloxyalkyl-modified organopolysiloxane, number average molecular weight Mn=5,000), or FM-0725 (single-terminal methacryloyloxyalkyl-modified organopolysiloxane, number average molecular weight Mn=10,000), manufactured by JNC Corporation; Examples of suitable organosiloxanes include X-22-174ASX (single-terminal methacryloyloxyalkyl-modified organopolysiloxane, functional group equivalent: 900 g / mol), KF-2012 (single-terminal methacryloyloxyalkyl-modified organopolysiloxane, functional group equivalent: 4,600 g / mol), and X-22-2426 (single-terminal methacryloyloxyalkyl-modified organopolysiloxane, functional group equivalent: 12,000 g / mol), all of which are manufactured by Gakushu Kogyo Co., Ltd.

[0062] Another embodiment of the (co)polymer (A) preferably has a structural unit derived from a compound (a212) of formula (II) in which n is 0 and p and q are 1. The present composition containing a (co)polymer (A) having a structural unit derived from such a compound (a212) is preferred in that it improves the topcoat adhesion of the antifouling coating film that is formed (e.g., adhesion of an antifouling coating film formed in the (n+1)th coat to an antifouling coating film formed in the nth coat when an antifouling coating film is formed by two or more coats, or adhesion between an old antifouling coating film and a new antifouling coating film when a new antifouling coating film (new antifouling coating film) is formed on an old antifouling coating film after the design specification period has elapsed). In this compound (a212), m is preferably 3 to 200, more preferably 5 to 70, from the viewpoint of ease of polymerization, etc.

[0063] As the compound (a212), commercially available products can be used. Examples of such commercially available products include FM-7711 (both terminally methacryloyloxyalkyl-modified organopolysiloxane, number average molecular weight Mn=1,000), FM-7721 (both terminally methacryloyloxyalkyl-modified organopolysiloxane, number average molecular weight Mn=5,000), and FM-7725 (both terminally methacryloyloxyalkyl-modified organopolysiloxane, number average molecular weight Mn=10,000), manufactured by JNC Corporation; and X-22-164 (both terminally methacryloyloxyalkyl-modified organopolysiloxane, functional group equivalent: 190 g / mol) and X-22-164AS (both terminally methacryloyloxyalkyl-modified organopolysiloxane, functional group equivalent X-22-164A (both terminally methacryloyloxyalkyl-modified organopolysiloxane, functional group equivalent: 860 g / mol), X-22-164B (both terminally methacryloyloxyalkyl-modified organopolysiloxane, functional group equivalent: 1630 g / mol), X-22-164C (both terminally methacryloyloxyalkyl-modified organopolysiloxane, functional group equivalent: 2,370 g / mol), X-22-164E (both terminally methacryloyloxyalkyl-modified organopolysiloxane, functional group equivalent: 3,900 g / mol), and X-22-167B (both terminally mercaptoalkyl-modified organopolysiloxane, functional group equivalent: 1,670 g / mol).

[0064] Furthermore, as another embodiment of the (co)polymer (A), it is preferable that the (co)polymer (A) has a structural unit derived from a compound (a213) of formula (II) in which n is 1 or greater. If the (co)polymer (A) has a structural unit derived from such a compound (a213), it is preferred in terms of low viscosity and ease of handling. In the compound (a213), m is preferably 50 to 1,000, and n is preferably 1 to 30.

[0065] The compound (a213) can be a commercially available product, such as KF-2001 (side-chain mercaptoalkyl-modified organopolysiloxane, functional group equivalent: 1,900 g / mol) or KF-2004 (side-chain mercaptoalkyl-modified organopolysiloxane, functional group equivalent: 30,000 g / mol), manufactured by Shin-Etsu Chemical Co., Ltd.

[0066] When the (co)polymer (A) has a structural unit derived from the monomer (a21), the content of the structural unit is preferably 0.5 to 50% by mass, more preferably 1 to 30% by mass, and even more preferably 1.5 to 15% by mass, relative to 100% by mass of all structural units of the (co)polymer (A), from the viewpoint that an antifouling coating film that is excellent in antifouling performance under alternating wet and dry conditions, water resistance, and adhesion to the substrate can be easily formed.

[0067] Alkoxyalkyl (meth)acrylate or aryloxyalkyl (meth)acrylate (a22) The (co)polymer (A) may contain a structural unit derived from an alkoxyalkyl (meth)acrylate or aryloxyalkyl (meth)acrylate (a22) (hereinafter also referred to as "monomer (a22)"). When the (co)polymer (A) contains a structural unit derived from the monomer (a22), the structural unit contained in the (co)polymer (A) may be one type, or two or more types. Furthermore, the (co)polymer (A) may contain both a structural unit derived from an alkoxyalkyl (meth)acrylate and a structural unit derived from an aryloxyalkyl (meth)acrylate.

[0068] The monomer (a22) preferably contains a compound represented by the following formula (V).

[0069] [In formula (V), R 24 represents a hydrogen atom or a methyl group, and R 25 represents a monovalent hydrocarbon group, and R 26 represents a divalent hydrocarbon group, and s represents an integer of 1 to 30.

[0070] In formula (V), R 24represents a hydrogen atom or a methyl group, and from the viewpoint of ease of polymerization, etc., a hydrogen atom is preferred, and from the viewpoint of the water resistance of the antifouling coating film to be formed, a methyl group is preferred.

[0071] The R 25 Specific examples of R include alkyl groups and aryl groups. 25 As the monovalent hydrocarbon group in the formula (I), from the viewpoints of the stability of the composition to be obtained and the physical properties of the antifouling coating film to be formed, a linear or branched alkyl group or aryl group having 1 to 6 carbon atoms is preferred, a linear alkyl group having 1 to 6 carbon atoms is more preferred, an alkyl group having 1 to 4 carbon atoms (e.g., methyl group, ethyl group, propyl group, butyl group) is even more preferred, and a methyl group is particularly preferred.

[0072] The R 26 Specific examples of the alkylene group include alkylene groups. The alkylene group is preferably an alkylene group having 2 to 6 carbon atoms, more preferably an alkylene group having 2 to 4 carbon atoms, further preferably an ethylene group or a propylene group, and particularly preferably an ethylene group.

[0073] In formula (V), s is preferably an integer of 1 to 15, more preferably an integer of 1 to 6, and even more preferably 1. By using a (co)polymer (A) having a structural unit derived from a monomer (a22) in which s falls within the above range, an antifouling coating film that has appropriate hydrophilicity and excellent water resistance can be easily formed.

[0074] Examples of the monomer (a22) include 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 4-methoxybutyl (meth)acrylate, 3-methoxy-n-propyl (meth)acrylate, 2-propoxyethyl (meth)acrylate, 2-butoxyethyl (meth)acrylate, isobutoxybutyl diglycol (meth)acrylate, 2-phenoxyethyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, ethoxypolyethylene glycol (meth)acrylate, butoxypolyethylene glycol (meth)acrylate, and phenoxypolyethylene glycol (meth)acrylate. Of these, 2-methoxyethyl (meth)acrylate is preferred, and 2-methoxyethyl methacrylate is more preferred.

[0075] When the (co)polymer (A) has a structural unit derived from the monomer (a22), the content of the structural unit is preferably 5 to 40% by mass, more preferably 10 to 35% by mass, and even more preferably 15 to 30% by mass, relative to 100% by mass of all structural units of the (co)polymer (A), from the viewpoint that an antifouling coating film excellent in antifouling performance, water resistance, and hardness can be easily formed.

[0076] Alkyl (meth)acrylate or aryl (meth)acrylate (a23) The (co)polymer (A) may contain a structural unit derived from an alkyl (meth)acrylate or aryl (meth)acrylate (a23) (hereinafter also referred to as "monomer (a23)"). When the (co)polymer (A) contains a structural unit derived from the monomer (a23), the structural unit contained in the (co)polymer (A) may be of one type, or may contain two or more types. Furthermore, the (co)polymer (A) may contain both a structural unit derived from an alkyl (meth)acrylate and a structural unit derived from an aryl (meth)acrylate.

[0077] The alkyl group in the monomer (a23) may be linear, branched, or cyclic, and is preferably an alkyl group having 1 to 18 carbon atoms, more preferably 1 to 8 carbon atoms, and even more preferably 1 to 4 carbon atoms. The aryl group is preferably an aryl group having 6 to 14 carbon atoms, and more preferably 6 to 10 carbon atoms.

[0078] Examples of the monomer (a23) include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, sec-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 3,5,5-trimethylhexyl (meth)acrylate, lauryl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, phenyl (meth)acrylate, and benzyl (meth)acrylate. Among these, methyl methacrylate is preferred from the viewpoint of being able to easily form an antifouling coating film that is excellent in coating film strength and further excellent in antifouling performance, and butyl acrylate is preferred from the viewpoint of being able to easily form an antifouling coating film that is excellent in water resistance and crack resistance, etc. It is also preferable to use methyl methacrylate and butyl acrylate in combination.

[0079] When the (co)polymer (A) has a structural unit derived from the monomer (a23), the content of the structural unit is preferably 0.2 to 40% by mass, more preferably 1 to 35% by mass, even more preferably 3 to 30% by mass, still more preferably 5 to 25% by mass, and particularly preferably 8 to 25% by mass, relative to 100% by mass of all structural units of the (co)polymer (A).

[0080] When the (co)polymer (A) has a structural unit derived from methyl methacrylate, the content of the structural unit is preferably 0.5 to 40 mass%, more preferably 1 to 35 mass%, and even more preferably 3 to 30 mass%, relative to 100 mass% of all structural units of the (co)polymer (A).

[0081] When the (co)polymer (A) has a structural unit derived from butyl acrylate, the content of the structural unit is preferably 0.2 to 20 mass%, more preferably 1 to 15 mass%, and even more preferably 3 to 10 mass%, relative to 100 mass% of all structural units of the (co)polymer (A).

[0082] Hydroxyalkyl (meth)acrylate (a24) The (co)polymer (A) may contain a structural unit derived from a hydroxyalkyl (meth)acrylate (a24) (hereinafter also referred to as "monomer (a24)"). When the (co)polymer (A) contains a structural unit derived from the monomer (a24), the structural unit contained in the (co)polymer (A) may be of one type, or may be of two or more types.

[0083] Examples of the monomer (a24) include hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 2-hydroxy-3-phenoxypropyl (meth)acrylate.

[0084] When the (co)polymer (A) has a structural unit derived from the monomer (a24), the content of the structural unit is preferably 0.5 to 30 mass%, more preferably 1 to 20 mass%, and even more preferably 2 to 15 mass%, relative to 100 mass% of all structural units of the (co)polymer (A).

[0085] Glycidyl (meth)acrylate (a25) The (co)polymer (A) may contain a structural unit derived from glycidyl (meth)acrylate (a25) (hereinafter also referred to as "monomer (a25)"). When the (co)polymer (A) contains a structural unit derived from the monomer (a25), the structural unit contained in the (co)polymer (A) may be of one type, or may be of two or more types.

[0086] When the (co)polymer (A) has a structural unit derived from the monomer (a25), the content of the structural unit is preferably 0.5 to 30% by mass, more preferably 1 to 20% by mass, and even more preferably 2 to 15% by mass, relative to 100% by mass of all structural units of the (co)polymer (A).

[0087] Unsaturated Carboxylic Acid Compound (a26) The (co)polymer (A) may contain a structural unit derived from an unsaturated carboxylic acid compound (a26) (hereinafter also referred to as "monomer (a26)"). When the (co)polymer (A) contains a structural unit derived from the monomer (a26), the structural unit contained in the (co)polymer (A) may be of one type, or may be of two or more types.

[0088] The monomer (a26) is a monomer having a carboxy group or an acid anhydride group in the molecule. Examples of the monomer (a26) include (meth)acrylic acid, (meth)acryloyloxyalkyl succinic acid, (meth)acryloyloxyalkyl phthalic acid, (meth)acryloyloxyalkyl hexahydrophthalic acid, itaconic acid, maleic acid, maleic anhydride, itaconic acid, crotonic acid, and 6-acrylamidohexanoic acid. Among these, (meth)acrylic acid is preferred in terms of the ease of handling and availability of the compound, the viscosity of the resulting (co)polymer (A), and the like.

[0089] When the (co)polymer (A) has a structural unit derived from the monomer (a26), the content of the structural unit is preferably 0.01 to 20% by mass, and more preferably 0.1 to 10% by mass, relative to 100% by mass of all structural units of the (co)polymer (A).

[0090] Metal ester group-containing unsaturated monomer (a27) The (co)polymer (A) may contain a structural unit derived from a metal ester group-containing unsaturated monomer (a27) (hereinafter also referred to as "monomer (a27)"). When the (co)polymer (A) contains a structural unit derived from the monomer (a27), the structural unit contained in the (co)polymer (A) may be of one type, or may be of two or more types.

[0091] Specific examples of the monomer (a27) include monomers having a metal ester group formed by bonding a metal with a carboxylic acid. Examples of the metal constituting the metal ester group include magnesium, calcium, neodymium, titanium, zirconium, iron, ruthenium, cobalt, nickel, copper, zinc, and aluminum.

[0092] The metal ester group is preferably a polyvalent metal ester group, and more preferably a divalent metal ester group represented by the following formula (VI): Specific examples of the "polyvalent metal ester group" and "divalent metal ester group" include groups formed by bonding a polyvalent metal or a divalent metal with a carboxylic acid.

[0093] [In formula (VI), M represents a metal, and * represents a bonding position.]

[0094] In formula (VI), M is a divalent metal, examples of which include the divalent metals listed above. Among these, metals in Groups 10 to 12 of the periodic table, such as nickel, copper, and zinc, are preferred, more preferably selected from the group consisting of copper and zinc, and even more preferably zinc.

[0095] Examples of the monomer (a27) include zinc di(meth)acrylate, copper di(meth)acrylate, zinc acrylate (methacrylate), copper acrylate (methacrylate), zinc di(3-(meth)acryloyloxypropionate), copper di(3-(meth)acryloyloxypropionate), zinc (meth)acrylate (naphthenate), and copper (meth)acrylate (naphthenate).

[0096] When the (co)polymer (A) has a structural unit derived from the monomer (a27), the content of the structural unit is preferably 0.5 to 30% by mass, more preferably 1 to 20% by mass, and even more preferably 2 to 15% by mass, relative to 100% by mass of all structural units of the (co)polymer (A).

[0097] Other vinyl compounds (a28) The (co)polymer (A) may contain a structural unit derived from another vinyl compound (a28) (hereinafter also referred to as "monomer (a28)"). When the (co)polymer (A) contains a structural unit derived from the monomer (a28), the structural unit contained in the (co)polymer (A) may be of one type, or may be of two or more types.

[0098] Examples of the monomer (a28) include styrene, α-methylstyrene, vinyl acetate, vinyl benzoate, vinyltoluene, acrylonitrile, methacrylonitrile, vinylpyridine, vinylpyrrolidone, and vinyl chloride.

[0099] When the (co)polymer (A) has a structural unit derived from the monomer (a28), the content of the structural unit is preferably 0.1 to 30% by mass, and more preferably 0.5 to 10% by mass, relative to 100% by mass of all structural units of the (co)polymer (A).

[0100] [Method for Synthesizing (Co)polymer (A)] The (co)polymer (A) can be synthesized, for example, by the following procedure: A solvent is charged into a reaction vessel equipped with a stirrer, a condenser, a thermometer, a dropping device, a nitrogen inlet tube, and a heating / cooling jacket, and the mixture is heated and stirred under a nitrogen stream at a temperature of 80 to 90°C. While maintaining the same temperature, a mixed liquid containing the monomers, polymerization initiator, chain transfer agent, solvent, and the like, which are reaction raw materials for the (co)polymer (A), is added dropwise from the dropping device, and a polymerization reaction is carried out to synthesize the (co)polymer (A).

[0101] The polymerization initiator is not particularly limited, and various radical polymerization initiators can be used. Specific examples include peroxides such as benzoyl peroxide, hydrogen peroxide, cumene hydroperoxide, tert-butyl hydroperoxide, potassium persulfate, sodium persulfate, and tert-butyl peroctoate (TBPO); and azo compounds such as 2,2'-azobis(isobutyronitrile) (AIBN), 2,2'-azobis(2-methylbutyronitrile) (AMBN), 2,2'-azobis(2,4-dimethylvaleronitrile) (ADVN), and 4,4'-azobis-4-cyanovaleric acid. One or more polymerization initiators may be used. The polymerization initiator may be added to the reaction system only at the start of the reaction, or may be added to the reaction system both at the start of the reaction and during the reaction.

[0102] When a polymerization initiator is used in the production of the (co)polymer (A), the amount used is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 5 parts by mass, per 100 parts by mass of the total of the monomers.

[0103] The chain transfer agent is not particularly limited, and examples thereof include α-methylstyrene dimer, thioglycolic acid, diterpene, terpinolene, γ-terpinene, mercaptans such as tert-dodecyl mercaptan and n-dodecyl mercaptan, halides such as carbon tetrachloride, methylene chloride, bromoform and bromotrichloroethane, and secondary alcohols such as isopropanol and glycerin. One or more types of chain transfer agents may be used.

[0104] When a chain transfer agent is used in the production of the (co)polymer (A), the amount used is preferably 0.1 to 5 parts by mass per 100 parts by mass of the total of the above-mentioned monomers.

[0105] Examples of the solvent include aromatic hydrocarbon solvents such as toluene, xylene, and mesitylene; alcohol solvents such as propanol, butanol, propylene glycol monomethyl ether, and dipropylene glycol monomethyl ether; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and methyl amyl ketone; ester solvents such as ethyl acetate and butyl acetate; and water.

[0106] <Rosin Compound (B)> The rosin compound (B) contains a rosin compound monomer (B1) and a rosin compound multimer (B2). Examples of the rosin compound include compounds containing abietic acid, palustric acid, isopimaric acid, or the like as main components.

[0107] The presence of the monomer (B1) and the multimer (B2) in the compound (B) can be determined, for example, by observing multiple peaks in the measurement results measured under the following GPC conditions: The content ratio of the monomer (B1) and the multimer (B2) in the compound (B) can be calculated, for example, from the ratio of the peak area of ​​the peak identified as the monomer (B1) to the peak area of ​​the peak identified as the multimer (B2) among the multiple peaks in the measurement results measured under the following GPC conditions:

[0108] GPC conditions Apparatus: "HLC-8420GPC" (manufactured by Tosoh Corporation) Columns: "TSKgel guard column Super H-L" (manufactured by Tosoh Corporation, 4.6 mm (inner diameter), 3.5 cm (length)) x 1, "TSKgel Super H2000" (manufactured by Tosoh Corporation, 6 mm (inner diameter), 15 cm (length)) x 1, "TSKgel Super H4000" (manufactured by Tosoh Corporation, 6 mm (inner diameter), 15 cm (length)) x 2 Eluent: tetrahydrofuran (THF) Flow rate: 0.600 mL / min Detector: RI Column thermostat temperature: 40°C Standard material: polystyrene Sample preparation method: Compound (B) whose concentration was adjusted with THF to a solid content of 1.5% by mass was filtered through a membrane filter (0.45 μm), and the resulting filtrate was used as a GPC measurement sample.

[0109] The total content of the (co)polymer (A) and the compound (B) in the composition is 5 to 40% by mass, preferably 10 to 35% by mass, more preferably 15 to 30% by mass, and even more preferably 20 to 25% by mass, based on 100% by mass of the solids content of the composition. When the total content is within the above range, an antifouling coating film having a stable coating film wear rate even under water immersion, particularly under dynamic immersion such as with a rotating water flow, and having excellent durability of antifouling properties can be easily formed.

[0110] The content of compound (B) in the composition is preferably 0.1 to 2 parts by mass, more preferably 0.13 to 1.5 parts by mass, even more preferably 0.15 to 1 part by mass, and particularly preferably 0.15 to 0.8 parts by mass, relative to 1 part by mass of the (co)polymer (A) in the composition. When the content of compound (B) relative to the content of (co)polymer (A) is within the above range, an antifouling coating film that has a stable coating film wear rate even under water immersion, particularly under dynamic immersion such as a rotating water flow, and that has excellent durability of antifouling properties can be easily formed.

[0111] The content of compound (B) in the composition is preferably 1 to 30 mass%, more preferably 1.5 to 20 mass%, even more preferably 2 to 15 mass%, still more preferably 2.5 to 9 mass%, and particularly preferably 3 to 6 mass%, based on 100 mass% of the solids content of the composition. When the content of compound (B) is within the above range, an antifouling coating film having excellent wood resistance, less temperature dependency of wear rate, and more stable coating film wear rate can be easily formed.

[0112] [Rosin-Based Compound Monomer (B1)] Examples of the rosin-based compound monomer (B1) include rosin, rosin derivatives, rosin metal salts, and pine tar. Among these, rosin is preferred because it enhances the effects of the present composition. Examples of the rosin include gum rosin, wood rosin, and tall oil rosin, with gum rosin being preferred. Examples of the rosin derivative include hydrogenated rosin, disproportionated rosin, maleated rosin, and formylated rosin. Examples of the rosin metal salt include zinc rosinate, calcium rosinate, copper rosinate, magnesium rosinate, and reaction products of other metal compounds with rosin. The monomer (B1) used in the present composition may be one type or two or more types.

[0113] The content of the monomer (B1) in the composition is preferably 0.5 to 25 mass%, more preferably 1 to 17 mass%, even more preferably 1.5 to 13 mass%, still more preferably 2 to 8 mass%, and particularly preferably 2.5 to 5 mass%, based on 100 mass% of the solids content of the composition. When the content of the monomer (B1) is within the above range, an antifouling coating film having high antifouling properties (adhesion suppression properties) against aquatic organisms can be easily formed.

[0114] [Rosin Compound Multimer (B2)] The rosin compound multimer (B2) is a multimer of the monomer (B1). The multimer is preferably a dimer. The multimer (B2) can be obtained by multimerizing (e.g., dimerizing) the monomer (B1) by, for example, the method described in JP-A-2002-201433. The multimer (B2) used in the present composition may be one type or two or more types.

[0115] The content of multimer (B2) in the composition is 0.07 to 5 parts by mass, more preferably 0.1 to 3 parts by mass, and even more preferably 0.12 to 1 part by mass, per part by mass of monomer (B1) in the composition. When the content of multimer (B2) relative to the content of monomer (B1) is within the above range, an antifouling coating film having less temperature dependency of wear and a more stable degree of wear can be easily formed, and an antifouling coating film having a stable degree of wear even under water immersion, particularly under dynamic immersion such as a rotating water flow, and having excellent durability of antifouling properties can be easily formed.

[0116] The content of the multimer (B2) in the present composition is preferably 0.01 to 1 part by mass, more preferably 0.02 to 0.5 parts by mass, and even more preferably 0.02 to 0.3 parts by mass, per part by mass of the (co)polymer (A) in the present composition. When the content of the multimer (B2) relative to the content of the (co)polymer (A) is within the above range, an antifouling coating film with less temperature dependence of wear rate can be easily formed.

[0117] The content of the multimer (B2) in the present composition is preferably 0.05 to 10 mass%, more preferably 0.1 to 5 mass%, even more preferably 0.15 to 3 mass%, still more preferably 0.2 to 2 mass%, and particularly preferably 0.25 to 1.5 mass%, relative to 100 mass% of the solids content of the present composition. When the content of the multimer (B2) relative to the solids content of the present composition is within the above range, an antifouling coating film that exhibits stable coating film wear even under water immersion, particularly under dynamic immersion such as with a rotating water flow, and that exhibits excellent durability of antifouling properties can be easily formed.

[0118] <Antifouling Agent (C)> In order to improve the antifouling properties of the antifouling coating film formed from the present composition, the present composition preferably further contains an antifouling agent (C). The antifouling agent (C) used in the present composition may be one type or two or more types.

[0119] The content of the antifouling agent (C) in the present composition is preferably 30 to 80 mass %, more preferably 40 to 70 mass %, relative to 100 mass % of the solids content of the present composition, from the viewpoint that an antifouling coating film having sufficient antifouling properties can be easily formed.

[0120] Examples of the antifouling agent (C) include (+ / -)-4-[1-(2,3-dimethylphenyl)ethyl]-1H-imidazole (also known as medetomidine); 4-bromo-2-(4-chlorophenyl)-5-(trifluoromethyl)-1H-pyrrole-3-carbonitrile (also known as tralopyril); metal pyrithione compounds such as copper pyrithione and zinc pyrithione; 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (also known as DCOIT); borane-nitrogen base adducts such as pyridinetriphenylborane and 4-isopropylpyridine(N-B)methyl(diphenyl)borane; N,N-dimethyl-N'-(3,4-dichlorophenyl)urea; Maleimide compounds such as N-(2,4,6-trichlorophenyl)maleimide, 2,3-dichloro-N-(2',6'-diethylphenyl)maleimide, and 2,3-dichloro-N-(2'-ethyl-6'-methylphenyl)maleimide; 2-methylthio-4-tert-butylamino-6-cyclopropylamino-1,3,5-triazine; 2,4,5,6-tetrachloroisophthalonitrile; carbamate compounds such as bisdimethyldithiocarbamoylzinc ethylenebisdithiocarbamate, zinc dimethyldithiocarbamate, and zinc ethylenebisdithiocarbamate; disulfide compounds such as chloromethyl-n-octyl disulfide and tetraalkylthiuram disulfide; N',N'-dimethyl-N-phenyl-(N-fluorodichloromethylthio)sulfamide; and copper compounds such as cuprous oxide, copper oxide, copper (metallic copper), and copper thiocyanate (also known as copper rhodanide). Among these, the antifouling agent (C) preferably contains at least one selected from medetomidine, tralopyril, DCOIT, a metal pyrithione compound (e.g., copper pyrithione, zinc pyrithione), and a copper compound (e.g., cuprous oxide, copper rhodanide), more preferably contains at least one selected from a metal pyrithione compound and cuprous oxide, and particularly preferably contains a metal pyrithione compound and cuprous oxide, in view of being able to easily form an antifouling coating film having high antifouling properties (adhesion inhibitory properties) against aquatic organisms.

[0121] Medetomidine has optical isomerism, and when medetomidine is used in the present composition, only one of the optical isomers may be used, or a mixture of the optical isomers in any ratio may be used. Furthermore, the medetomidine may be an imidazolium salt of medetomidine or an adduct of medetomidine with a metal or the like. In this case, the imidazolium salt or the adduct with a metal or the like may be used as a raw material when preparing the present composition, and the imidazolium salt or the adduct with a metal or the like may be formed in the present composition or the antifouling coating film.

[0122] Cuprous oxide: The cuprous oxide is preferably in the form of particles having a median diameter (D50) of about 0.1 to 30 μm, since this allows for the easy formation of an antifouling coating film that has long-lasting antifouling properties. Furthermore, cuprous oxide that has been surface-treated with glycerin, stearic acid, lauric acid, sucrose, lecithin, mineral oil, or the like is preferred, since this allows for the easy production of a composition that has excellent long-term stability during storage.

[0123] When the present composition contains cuprous oxide, the content thereof is preferably 30 to 80 mass %, more preferably 40 to 70 mass %, relative to 100 mass % of the solids content of the present composition, from the viewpoint that an antifouling coating film having sufficient antifouling properties can be easily formed.

[0124] Metal pyrithione compound: Copper pyrithione and zinc pyrithione are preferred as the metal pyrithione compound, with copper pyrithione being preferred from the viewpoint of easily forming an antifouling coating film that is excellent in water resistance, crack resistance, and antifouling properties, etc. When the present composition contains a metal pyrithione, the content thereof is preferably 0.3 to 20% by mass, more preferably 0.5 to 15% by mass, relative to 100% by mass of the solids content of the present composition, from the viewpoint of easily forming an antifouling coating film that has sufficient antifouling properties, etc.

[0125] <Other Optional Components> The present composition may contain other optional components in addition to the (co)polymer (A), compound (B), and antifouling agent (C), as necessary. Examples of such other optional components include pigments (D), solvents (E), plasticizers (F), anti-sagging agents / anti-settling agents (G), dehydrating agents (H), other binder components (I), monocarboxylic acid compounds, polybasic acids, antifoaming agents, and wetting and dispersing agents. When other optional components are used in the present composition, the other optional components used may each be one type or two or more types.

[0126] [Pigment (D)] The pigment (D) is not particularly limited, and a conventionally known pigment can be used. Examples of the pigment (D) include flat pigments (D1), zinc oxide (D2), and other pigments (D3) other than these. The pigment (D) used in the present composition may be one type or two or more types.

[0127] When the composition contains pigment (D), the content thereof is preferably 1 to 50 mass%, more preferably 5 to 40 mass%, and even more preferably 10 to 30 mass%, based on 100 mass% of the solids content of the composition. When the content of pigment (D) is within the above range, a composition with excellent coating workability can be easily formed, and an antifouling coating film with excellent adhesion to the substrate due to stress relaxation can be easily formed.

[0128] [Flat pigment (D1)] The use of a flat pigment (D1) in the present composition tends to suppress cracks that may occur in the antifouling coating film to be formed, and an antifouling coating film with reduced internal stress can be easily formed. When a flat pigment (D1) is used in the present composition, the flat pigment (D1) used may be one type or two or more types.

[0129] Examples of the flat pigment (D1) include talc, mica, glass flakes, aluminum flakes, scaly iron oxide, stainless steel flakes, and plastic flakes. Among these, talc and mica are preferred, and talc is more preferred, from the viewpoint of being able to further suppress the cracks.

[0130] The median diameter (D50) of the flat pigment (D1) is preferably 5 to 200 μm. The average aspect ratio (median diameter / average thickness) of the flat pigment (D1) is preferably 3 to 150, more preferably 5 to 100.

[0131] In this specification, D50 can be measured using a laser scattering diffraction particle size distribution analyzer, for example, "SALD 2200" (manufactured by Shimadzu Corporation). The average thickness can be calculated as the average value of the thicknesses of several tens to several hundreds of pigment particles by observing the main surface of the flat pigment (D1) from a direction horizontal to the main surface using a scanning electron microscope (SEM), for example, "XL-30" (manufactured by Philips).

[0132] When the present composition contains a flat pigment (D1), the content thereof is preferably 1 to 20 mass %, more preferably 3 to 10 mass %, relative to 100 mass % of the solids content of the present composition, from the viewpoint that an antifouling coating film having the above-mentioned effects can be easily formed.

[0133] [Zinc oxide (D2)] The use of zinc oxide (D2) in the present composition tends to facilitate the formation of an antifouling coating film that has sufficient antifouling properties and excellent water resistance. The shape, median diameter (D50), etc. of zinc oxide (D2) are not particularly limited, and when zinc oxide (D2) is used in the present composition, two or more types of zinc oxide (D2) that differ in shape, D50, etc. may be used.

[0134] The D50 of zinc oxide (D2) is preferably 0.01 μm or more, more preferably 0.05 μm or more, particularly preferably 0.1 μm or more, from the viewpoint of making zinc oxide (D2) more easily dispersible in the composition and improving the antifouling properties of the antifouling coating film obtained, and is preferably 10 μm or less, more preferably 5 μm or less.

[0135] When the present composition contains zinc oxide (D2), the content thereof is preferably 1 to 30 mass %, more preferably 5 to 20 mass %, relative to 100 mass % of the solids content of the present composition, from the viewpoint that an excellent antifouling coating film can be easily formed due to the above-mentioned effects, etc.

[0136] [Other Pigments (D3)] The present composition may contain a pigment (D3) other than the flat pigment (D1) and zinc oxide (D2), for example, for the purpose of coloring the antifouling coating film or concealing the base, or for the purpose of adjusting the strength of the antifouling coating film to an appropriate level. When the other pigment (D3) is used in the present composition, the other pigment (D3) used may be one type or two or more types.

[0137] Examples of other pigments (D3) include extender pigments such as silica, zinc phosphate, clay, potassium feldspar, calcium carbonate, kaolin, alumina white, white carbon, aluminum hydroxide, magnesium carbonate, barium carbonate, barium sulfate, calcium sulfate, and zinc sulfide; and coloring pigments such as red iron oxide (red iron oxide), titanium white (titanium oxide), yellow iron oxide, carbon black, naphthol red, and phthalocyanine blue.

[0138] When the present composition contains other pigments (D3), the total content thereof may be appropriately set depending on the coloring property and hiding property required for the antifouling coating film to be formed, the viscosity required for the present composition, etc., but is preferably 0.01 to 20% by mass, more preferably 0.1 to 15% by mass, relative to 100% by mass of the solids content of the present composition.

[0139] [Solvent (E)] The present composition may contain a solvent (E) such as water or an organic solvent, as needed, for the purpose of adjusting the viscosity of the composition, etc. The solvent (E) is preferably an organic solvent, and preferably does not substantially contain water. In other words, the present composition is preferably an organic solvent-based composition rather than a water-based composition. Here, "substantially does not contain water" means that the proportion of water in the solvent (E) is 10% by mass or less, preferably 2% by mass or less. When a solvent (E) is used in the present composition, the solvent (E) used may be one type or two or more types.

[0140] Examples of the organic solvent include aromatic organic solvents such as xylene, toluene, and ethylbenzene; ketones such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; aliphatic monohydric alcohols (having 1 to 10 carbon atoms, preferably about 2 to 5 carbon atoms) such as ethanol, isopropyl alcohol, n-butanol, isobutanol, and propylene glycol monomethyl ether; and ester solvents such as ethyl acetate and butyl acetate.

[0141] The content of solvent (E) in the composition may be 0% by mass, but when the composition contains solvent (E), it is preferable to appropriately set the content so as to obtain a desired viscosity depending on the coating method of the composition, and the content is usually preferably 10 to 50% by mass, and more preferably 15 to 40% by mass, relative to 100% by mass of the composition. If the content of solvent (E) is too high, problems such as a decrease in anti-sagging properties may occur.

[0142] [Plasticizer (F)] The present composition may contain a plasticizer (F) for the purpose of imparting plasticity to the antifouling coating film to be formed, etc. When a plasticizer (F) is used in the present composition, the plasticizer (F) used may be one type or two or more types.

[0143] Examples of the plasticizer (F) include tricresyl phosphate (TCP), dioctyl phthalate (DOP), diisodecyl phthalate (DIDP), adipic acid diester, and acetyl tributyl citrate.

[0144] When the present composition contains a plasticizer (F), the content thereof is preferably 0.1 to 10 mass %, more preferably 0.5 to 5 mass %, relative to 100 mass % of the solids content of the present composition, from the viewpoint of being able to maintain good plasticity of the antifouling coating film to be formed, etc.

[0145] [Anti-sagging agent / anti-settling agent (G)] The present composition may contain an anti-sagging agent / anti-settling agent (G) for the purpose of adjusting the viscosity of the composition, etc. When an anti-sagging agent / anti-settling agent (G) is used in the present composition, the anti-sagging agent / anti-settling agent (G) used may be one type or two or more types.

[0146] Examples of the anti-sagging agent / anti-settling agent (G) include organic clay waxes (e.g., stearate salts of Al, Ca, and Zn, lecithin salts, and alkylsulfonates), organic waxes (e.g., polyethylene wax, oxidized polyethylene wax, amide wax, polyamide wax, and hydrogenated castor oil wax), mixtures of organic clay waxes and organic waxes, and synthetic finely powdered silica.

[0147] When the present composition contains an anti-sagging agent / anti-settling agent (G), the content thereof is preferably 0.01 to 10 mass %, more preferably 0.1 to 3 mass %, relative to 100 mass % of the solid content of the present composition.

[0148] [Dehydrating Agent (H)] The present composition may contain a dehydrating agent (H) for the purpose of improving its storage stability, etc. When a dehydrating agent (H) is used in the present composition, the dehydrating agent (H) used may be one type or two or more types.

[0149] Examples of the dehydrating agent (H) include inorganic dehydrating agents such as synthetic zeolite, anhydrous gypsum, and hemihydrate gypsum (also known as calcined gypsum), and examples of organic dehydrating agents include alkoxysilanes such as tetramethoxysilane, tetraethoxysilane (ethyl silicate), tetrapropoxysilane, tetrabutoxysilane, tetraphenoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, and trimethylethoxysilane, or condensates thereof, and alkyl orthoformates such as methyl orthoformate and ethyl orthoformate.

[0150] When the present composition contains a dehydrating agent (H), the content thereof is preferably 0.1 to 20 mass %, more preferably 0.2 to 15 mass %, based on 100 mass % of the solid content of the present composition.

[0151] [Other Binder Component (I)] The present composition may contain another binder component (I) other than the (co)polymer (A) for the purpose of imparting static antifouling property, water resistance, crack resistance, strength, etc. to the antifouling coating film to be formed. When the other binder component (I) is used in the present composition, the other binder component (I) to be used may be one type or two or more types.

[0152] Other examples of the binder component (I) include (meth)acrylic (co)polymers ((meth)acrylic resins), vinyl polymers, chlorinated paraffins, n-paraffins, terpene phenols, and polyvinyl ethyl ethers.

[0153] Examples of the acrylic (co)polymer include (co)polymers obtained by polymerizing one or more selected from the other monomers (a21) to (a26) and the monomer (a28) in the column for the (co)polymer (A). From the viewpoint of static soil resistance and the like, it is preferable that the (co)polymer contain a structural unit derived from the monomer (a22).

[0154] Alternatively, commercially available products may be used as the binder component (I). Examples of such commercially available products include "DIANAL BR-106" (a (meth)acrylic (co)polymer) manufactured by Mitsubishi Chemical Corporation and "TOYOPARAX A-40 / A-50 / A-70 / A-145 / A-150" (chlorinated paraffins) manufactured by Tosoh Corporation.

[0155] When the present composition contains other binder component (I), the content thereof is preferably 1 to 30% by mass relative to 100% by mass of the solid content of the present composition.

[0156] <Method for preparing the present composition> The present composition can be prepared by a method similar to that for preparing a known general antifouling coating composition. Specifically, the present composition can be prepared by synthesizing the (co)polymer (A), then adding the obtained (co)polymer (A) (a solution thereof), the compound (B), the antifouling agent (C), and, if necessary, the other optional components, all at once or successively to a container, and stirring and mixing them.

[0157] <Antifouling Coating Film, Substrate with Antifouling Coating Film, Manufacturing Method Thereof, and Method for Antifouling a Substrate> An antifouling coating film according to one embodiment of the present invention (hereinafter also referred to as "the present coating film") is formed from the present composition and can usually be formed by drying the present composition. The present coating film is usually formed on a substrate and used as a substrate with the present coating film, comprising the substrate and the present coating film. A suitable example of a method for manufacturing a substrate with the present coating film includes a step of applying the present composition to at least a portion of the substrate and then drying the composition. Furthermore, a method for antifouling a substrate according to one embodiment of the present invention includes a step of forming the present coating film on at least a portion of the substrate. Because the method for manufacturing a substrate with the present coating film includes a step of forming the present coating film on at least a portion of the substrate, it can also be said to be a method for antifouling a substrate.

[0158] The substrate is not particularly limited, but since the present composition is preferably used for antifouling substrates in a wide range of industrial fields such as ships, fisheries, and underwater structures, examples of the substrate include ships (e.g., hull shells for large steel ships such as container ships and tankers, fishing boats, FRP boats, wooden boats, yachts, etc., including both new ships and repaired ships); fishing materials (e.g., ropes, fishing nets, fishing gear, floats, buoys); diver suits; underwater goggles; oxygen cylinders; swimsuits; torpedoes; structures such as oil pipelines, water supply and discharge pipes, circulating water pipes, water supply and discharge outlets for thermal and nuclear power plants, submarine cables, seawater utilization equipment (e.g., seawater pumps), megafloats, coastal roads, undersea tunnels, port facilities, various underwater civil engineering structures in canals and waterways, etc. Among these, ships, underwater structures, and fishery materials are preferred, ships and underwater structures are more preferred, and ships are particularly preferred.

[0159] The substrate may be a substrate treated with other treatment agents such as a rust inhibitor, a substrate having a coating film such as a primer formed on its surface, or a substrate having the present coating film formed thereon. There are no particular restrictions on the object with which the present coating film comes into direct contact.

[0160] The method for applying the present composition to at least a part of a substrate is not particularly limited, and examples thereof include a method of coating the present composition on a substrate and a method of immersing the substrate in the present composition (impregnating the substrate with the present composition). Examples of the coating method include known methods such as methods using a brush, a roller, or a spray.

[0161] The drying method may be, for example, a method in which the mixture is left standing at room temperature (e.g., 25° C.) for preferably about 0.5 to 14 days, more preferably about 1 to 7 days. The drying may be carried out under heating or while blowing air.

[0162] The thickness of the present coating film after drying may be selected as desired depending on the degree of wear of the present coating film, the intended use and period of use of the present coating film, etc., but is preferably, for example, about 30 to 1,000 μm. Methods for forming an antifouling coating film of this thickness include methods in which the present composition is applied one or more times so as to obtain a dried coating film of a thickness of preferably 10 to 300 μm, more preferably 30 to 200 μm per application.

[0163] The substrate with the present coating film can also be produced by a method including step (I) of forming the present coating film and step (II) of attaching the obtained present coating film to a substrate. Step (I) is not particularly limited, and an example thereof includes a method in which the present composition is applied to at least a portion of a substrate, and a support that has been subjected to a release treatment as necessary is used instead of the substrate. Step (II) is also not particularly limited, and an example thereof includes a method described in JP 2013-129724 A.

[0164] Hereinafter, one embodiment of the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Note that the "solid content" of each component used in the examples refers to the component excluding volatile components contained in each component as a solvent, and the solid content is defined as the content obtained by drying each component in a hot air dryer at 105°C for 1 hour.

[0165] Production Example 1: Production of Silyl Ester-Based Copolymer Solution (A-1) All of the following reaction steps were carried out under a nitrogen stream. A reaction vessel equipped with a stirrer, condenser, thermometer, dropping device, nitrogen inlet tube, and heating / cooling jacket was charged with 53.85 parts by mass of xylene and heated to 80±3°C with stirring. While maintaining this temperature, a raw material mixture consisting of a monomer mixture of 50.0 parts by mass of triisopropylsilyl methacrylate, 28.0 parts by mass of 2-methoxyethyl methacrylate, 14.0 parts by mass of methyl methacrylate, and 8.0 parts by mass of butyl acrylate, and 1.3 parts by mass of 2,2'-azobisisobutyronitrile as a charge initiator, was added dropwise into the reaction vessel from the dropping device over 2 hours. The mixture was then stirred at the same temperature for 1 hour, and then stirred at 85°C for 1 hour. After this, the mixture was heated to 105°C over 3 hours while 0.4 parts by mass of 2,2'-azobisisobutyronitrile was added in four portions. To the reaction solution obtained after the temperature increase, 12.81 parts by mass of xylene was added to produce a pale yellow, transparent silyl ester copolymer solution (A-1).

[0166] <Production Examples 2 to 4: Production of Silyl Ester-Based Copolymer Solutions (A-2) to (A-4)> Silyl ester-based copolymer solutions (A-2) to (A-4) were produced in the same manner as in Production Example 1, except that the types and charging ratios of the raw material mixtures used in Production Example 1 were changed as shown in Table 1. Note that "FM-0711" in Table 1 is a one-terminal methacryloyloxyalkyl-modified organopolysiloxane (Mn = 1,000) manufactured by JNC Corporation.

[0167] <Viscosity of Copolymer Solution> The viscosity of the produced copolymer solution was measured at 25° C. and a rotation speed of 10 rpm using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd.). The results are shown in Table 1.

[0168] <Number-average molecular weight (Mn) and weight-average molecular weight (Mw) of copolymer> The Mn and Mw of the copolymer in the produced copolymer solution were measured using GPC (gel permeation chromatography) under the following conditions. The results are shown in Table 1. GPC conditions Apparatus: "HLC-8320GPC" (manufactured by Tosoh Corporation) Column: "TSKgel guard column Super MP (HZ)-M" + "TSKgel Super Multipore HZ-M" + "TSKgel Super Multipore HZ-M" (all manufactured by Tosoh Corporation) Eluent: tetrahydrofuran (THF) Flow rate: 0.35 mL / min Detector: RI Column thermostatic bath temperature: 40°C Standard substance: polystyrene Sample preparation method: The polymer solution prepared in each Production Example was diluted with THF, and then filtered through a membrane filter to obtain a filtrate, which was used as a GPC measurement sample.

[0169]

[0170] [Examples 1 to 12 and Comparative Examples 1 to 3] Underwater antifouling paint compositions were prepared by mixing and stirring the components in the proportions (parts by mass) shown in Table 2. The amount of each component shown in Table 2 indicates the amount blended as is. For example, in Example 1, the amount of fatty acid amide blended as is (total) was 1 part by mass. Since the solid content of the fatty acid amide was 20% by mass, the amount of fatty acid amide itself blended in Example 1 was 0.2 parts by mass. Details of each component used in the examples and comparative examples are shown in Table 3.

[0171] <Woodblock resistance> An epoxy resin-based anticorrosive paint composition (trade name "Banno 1500", manufactured by Chugoku Toryo Co., Ltd.) was applied to a sandblasted steel plate measuring 150 mm long x 70 mm wide x 1.6 mm thick to a dry film thickness of 150 μm and dried, and then an epoxy resin-based binder paint composition (trade name "Banno 1500RZ", manufactured by Chugoku Toryo Co., Ltd.) was applied to a dry film thickness of 100 μm and dried. Subsequently, each of the prepared underwater antifouling paint compositions was applied once to give an antifouling coating film with a dry film thickness of 300 μm, and the resulting film was dried at 23° C. for 1 day to prepare a test plate.

[0172] A piece of wood measuring 30 mm in length, 30 mm in width, and 10 mm in thickness was placed in the center of the antifouling coating film of the prepared test panel, and a pressure of 40 kgf / cm was applied vertically (towards the antifouling coating film) from above the piece of wood. 2 After applying a pressure of 3.9 MPa for 20 minutes, the condition of the coating surface was observed (the degree of deformation of the antifouling coating film was measured). The evaluation criteria are shown in Figure 1. In Figure 1, 10 is the wood piece and 20 is the antifouling coating film. Evaluation criteria 5 indicates the best condition, with no deformation of the antifouling coating film 20. Evaluation criteria 4 indicates a good condition, with some deformation of the antifouling coating film 20 but no trace of the wood piece 10 being visible on the antifouling coating film 20. Evaluation criteria 3, 2, and 1 indicate a condition in which the antifouling coating film 20 is deformed and traces of the wood piece 10 are visible, with the degree of damage (deformation) ranking in the order 3 < 2 < 1. The results are shown in Table 2.

[0173] <Dynamic Antifouling Properties> An epoxy resin-based anticorrosive coating composition (trade name "Banno 1500", manufactured by Chugoku Toryo Co., Ltd.) was applied to a sandblasted steel plate (100 mm long x 200 mm wide x 2.3 mm thick) to a dry film thickness of 150 μm and dried. An epoxy resin-based binder coating composition (trade name "Banno 1500RZ", manufactured by Chugoku Toryo Co., Ltd.) was then applied to a dry film thickness of 100 μm and dried. Each of the prepared underwater antifouling coating compositions was then applied once to the plate to give an antifouling coating film with a dry film thickness of 200 μm. The plate was then dried at 25°C for 7 days to prepare a test plate with an antifouling coating film. The three coatings were performed once per day. The prepared test plate with the antifouling coating film was attached to a rotating cylinder approximately 0.5 m below the water surface in Hiroshima Bay and immersed at a speed of approximately 15 knots. Six months after the start of immersion under these immersion conditions, the area occupied by aquatic organisms on the antifouling coating film was measured, and the dynamic antifouling properties of the antifouling coating film were evaluated according to the dynamic antifouling properties evaluation criteria based on the area occupied by aquatic organisms described below. The results are shown in Table 2. Under these immersion conditions, due to the characteristics of the immersion sea area and conditions, fouling by aquatic organisms, particularly slime and marine plant organisms, is likely to occur.

[0174] (Evaluation criteria for dynamic antifouling properties based on the area occupied by aquatic organisms) 5: The total area occupied by aquatic organisms is less than 10% of the entire antifouling coating film (100%). 4: The area is 10% or more but less than 20% of the total. 3: The area is 20% or more but less than 40% of the total. 2: The area is 40% or more but less than 70% of the total. 1: The area is 70% or more of the total.

[0175] <Water temperature dependence of wear rate of antifouling coating film> Each of the prepared underwater antifouling coating compositions was applied to a hard vinyl chloride plate measuring 50 mm long x 50 mm wide x 1.5 mm thick using an applicator so that the dried coating film would be about 200 μm thick, and the plate was dried indoors at room temperature (about 20° C.) for 7 days to prepare a test plate. Two test plates were prepared in the same manner for each underwater antifouling coating composition.

[0176] The prepared test plate was attached to the side of a rotating drum placed in a thermostatic chamber filled with seawater at 25°C or 40°C, and rotated at a peripheral speed of 15 knots. The amount of film thickness loss of the antifouling coating film 10 months after the start of rotation was measured, and the water temperature dependence of wear was calculated using the following formula. The results are shown in Table 2. Water temperature dependence of wear = (film thickness loss after 10 months of immersion in 40°C seawater) / (film thickness loss after 10 months of immersion in 25°C seawater).

[0177] The water temperature dependence of the degree of wear of the antifouling coating film formed from the underwater antifouling paint composition obtained in the Examples was lower than the water temperature dependence of the degree of wear of the antifouling coating film formed from the underwater antifouling paint composition obtained in Comparative Example 2, and the change in the degree of wear of the coating film depending on the sea area in which the ship navigates is small. Therefore, even if the ship navigates in high-temperature sea areas more frequently than expected, there is a low risk that the underlying substrate will be exposed due to excessive wear of the antifouling coating film, causing fouling of the substrate.

[0178]

[0179]

[0180] The content ratios of the rosin compound monomer and the rosin compound multimer (dimer) in "rosin compound 1" in Table 3 are peak area ratios measured by GPC under the following conditions. GPC conditions Apparatus: "HLC-8420GPC" (manufactured by Tosoh Corporation) Columns: "TSKgel guard column Super H-L" (manufactured by Tosoh Corporation, 4.6 mm (inner diameter), 3.5 cm (length)) x 1, "TSKgel Super H2000" (manufactured by Tosoh Corporation, 6 mm (inner diameter), 15 cm (length)) x 1, "TSKgel Super H4000" (manufactured by Tosoh Corporation, 6 mm (inner diameter), 15 cm (length)) x 2 Eluent: tetrahydrofuran (THF) Flow rate: 0.600 mL / min Detector: RI Column thermostat temperature: 40°C Standard material: polystyrene Sample preparation method: Rosin compound 1, the concentration of which was adjusted with THF to a solid content of 1.5% by mass, was filtered through a membrane filter (0.45 μm), and the resulting filtrate was used as a GPC measurement sample.

[0181] 10: Wood chip 20: Antifouling coating film

Claims

1. An underwater antifouling coating composition comprising a hydrolyzable (co)polymer (A) having a constituent unit derived from a hydrolyzable group-containing monomer, a rosin-based compound (B), and an antifouling agent (C), wherein the rosin-based compound (B) comprises a rosin-based compound monomer (B1) and a rosin-based compound multimer (B2), the content of the multimer (B2) per part by mass of the monomer (B1) is 0.07 to 5 parts by mass, and the total content of the (co)polymer (A) and the rosin-based compound (B) per 100% by mass of the solids content of the underwater antifouling coating composition is 5 to 40% by mass.

2. The underwater antifouling coating composition according to claim 1, wherein the (co)polymer (A) contains a structural unit derived from a silyl ester group-containing monomer (a1) represented by the following formula (1): X-SiR 1 R 2 R 3 In formula (1), X is an ethylenically unsaturated acyloxy group, and R 1 ~R 3 each independently represents a linear or branched alkyl group having 1 to 20 carbon atoms, an alicyclic alkyl group having 3 to 10 carbon atoms, or an aromatic group having 6 to 20 carbon atoms.

3. The above R 1 ~R 3 The underwater antifouling coating composition according to claim 2, wherein each of the groups is an isopropyl group.

4. The underwater antifouling coating composition according to claim 2, wherein the silyl ester group-containing monomer (a1) is triisopropylsilyl methacrylate.

5. The underwater antifouling coating composition according to claim 1, wherein the content of the rosin compound (B) is 0.1 to 2 parts by mass per part by mass of the (co)polymer (A).

6. The underwater antifouling coating composition according to claim 1, wherein the content of the multimer (B2) is 0.01 to 1 part by mass per part by mass of the (co)polymer (A).

7. The underwater antifouling coating composition according to claim 1, wherein the antifouling agent (C) contains cuprous oxide, and the content of the cuprous oxide is 30 to 80 mass% relative to 100 mass% of the solids content of the underwater antifouling coating composition.

8. The underwater antifouling coating composition according to claim 1, further comprising a pigment (D).

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

10. A substrate with an antifouling coating film, comprising a substrate and the antifouling coating film according to claim 9.

11. A method for producing a substrate with an antifouling coating film, comprising the steps of applying the underwater antifouling coating composition according to any one of claims 1 to 8 to at least a part of the substrate, and then drying the composition.

12. A method for antifouling a substrate, comprising the step of forming the antifouling coating film according to claim 9 on at least a part of the substrate.