JP2023101831A - Antifouling coating composition - Google Patents

Abstract

To provide an antifouling coating composition having good storage stability and excellent antifouling performance.SOLUTION: There is provided an antifouling coating composition which comprises an acrylic resin (A), a rosin-based compound (B) and medetomidine (C), wherein the acrylic resin (A) is a copolymer obtained by copolymerizing a polymerizable unsaturated monomer component containing a hydrophilic monomer and a hydrophobic monomer, the hydrophilic monomer is at least one selected from an alkoxy (meth)acrylate, a polymerizable unsaturated monomer containing a hydroxyl group and a polymerizable unsaturated monomer containing a carboxyl group, the hydrophobic monomer is at least one selected from an alkyl (meth)acrylate and an aromatic vinyl compound, the polymerizable unsaturated monomer component contains no triisopropylsilyl (meth)acrylate, the copolymerization ratio of the hydrophilic monomer in the polymerizable unsaturated monomer used in the polymerization of the acrylic resin (A) is 5 mass% or more and the nonvolatile content mass ratio of the acrylic resin (A) to the rosin-based compound (B) is 10/90 to 90/10.SELECTED DRAWING: None

Description

The present invention relates to an antifouling coating composition.

Since the hull is a steel structure and is always exposed to the seashore environment, the main parts are usually coated with a rust-preventive paint as a base and then coated with a top coat for finishing.

However, the bottom part of the hull, that is, the part below the waterline that is in direct contact with seawater is coated with an antifouling paint composition [AF (Anti-Fouling) paint] as a topcoat after applying a rust-preventing paint as a base coat.

The reason why such an antifouling coating composition is applied is that while the ship is moored in a harbor, aquatic organisms such as oysters, barnacles, and other shellfish and seaweed adhere to the bottom of the ship, increasing water resistance. In order to suppress the speed and fuel efficiency of the hull from deteriorating, the surface of the bottom of the ship needs to be resistant to these aquatic organisms.

BACKGROUND ART In recent years, various hydrolyzable antifouling paint compositions containing hydrolyzable resins have been developed as antifouling paint compositions. For example, Patent Documents 1 to 3 disclose antifouling coating compositions containing a hydrolyzable resin obtained by copolymerizing triisopropylsilyl acrylate or triisopropylsilyl methacrylate.

Rosin is widely used in hydrolyzable antifouling paint compositions because it has slight solubility in alkaline solutions and dissolves in weakly alkaline seawater. However, since rosin by itself is physically weak, it is necessary to blend other synthetic resins or the like to compensate for this.

When the coating film formed from the hydrolyzable antifouling coating composition comes into contact with seawater, the hydrolyzable resin gradually hydrolyzes and the coating film dissolves in seawater, and the surface of the coating film continues to be renewed. It is believed that the adhesion of aquatic organisms is suppressed and the antifouling performance can be maintained over a long period of time.

Japanese Patent Publication No. 5-32433 JP-A-63-215780 JP-A-7-102193

Although hydrolyzable antifouling paint compositions are excellent in antifouling performance over a long period of time, hydrolyzable resins are prone to deterioration due to contamination with moisture during storage, and depending on the type and condition of seawater, it may be difficult to demonstrate its antifouling performance.

Accordingly, an object of the present invention is to provide an antifouling coating composition having good storage stability and excellent antifouling performance.

The present inventors have earnestly studied the above problems. As a result, the inventors have found that even if a resin having no hydrolyzable group such as a triisopropylsilyl group is used, it is possible to obtain a paint which is excellent not only in storage stability but also in antifouling performance.

That is, the present invention relates to the following.
Section 1.
including acrylic resin (A), rosin compound (B) and medetomidine (C),
The acrylic resin (A) is a copolymer obtained by copolymerizing a polymerizable unsaturated monomer component containing a hydrophilic monomer and a hydrophobic monomer,
The hydrophilic monomer is at least one selected from alkoxy (meth) acrylates, hydroxyl group-containing polymerizable unsaturated monomers and carboxyl group-containing polymerizable unsaturated monomers,
The hydrophobic monomer is at least one selected from alkyl (meth)acrylates and aromatic vinyl compounds,
wherein the polymerizable unsaturated monomer component does not contain triisopropylsilyl (meth)acrylate,
The copolymerization ratio of the hydrophilic monomer in the polymerizable unsaturated monomer used for polymerization of the acrylic resin (A) is 5% by mass or more,
An antifouling coating composition, wherein the acrylic resin (A)/rosin-based compound (B) has a non-volatile content mass ratio of 10/90 to 90/10.
Section 2.
Item 2. The antifouling coating composition according to Item 1, wherein the hydrophilic monomer comprises an alkoxy (meth)acrylate as part of its components.
Item 3.
Item 3. The antifouling coating composition according to Item 1 or 2, wherein the hydrophilic monomer contains a carboxyl group-containing polymerizable unsaturated monomer as a part of its components.
Section 4.
4. The antifouling coating composition according to any one of Items 1 to 3, wherein the acrylic resin (A) has a solubility parameter in the range of 8.0 to 11.0.
Item 5.
Item 5. The antifouling coating composition according to any one of items 1 to 4, wherein the glass transition temperature of the acrylic resin (A) is in the range of 10 to 60°C.
Item 6.
Item 6. The antifouling coating composition according to any one of Items 1 to 5, wherein the rosin compound (B) is a rosin metal salt.
Item 7.
Item 7. The antifouling paint composition according to any one of items 1 to 6, comprising at least one antifouling agent selected from cuprous oxide, zinc oxide, copper pyrithione and zinc pyrithione.
Item 8.
A coated article having a coating film comprising the antifouling coating composition according to any one of Items 1 to 7.

The antifouling coating composition of the present invention has excellent storage stability, and the formed coating film can exhibit stable antifouling properties.

[Acrylic resin (A)]
The antifouling coating composition of the present invention contains an acrylic resin (A). The acrylic resin (A) is a copolymer of polymerizable unsaturated monomers containing (meth)acrylate as a main component, and is a copolymer obtained by copolymerizing polymerizable unsaturated monomer components containing hydrophilic monomers and hydrophobic monomers.

In the present invention, the polymerizable unsaturated monomer refers to a monomer having one or more (eg, 1 to 4) polymerizable unsaturated groups. A polymerizable unsaturated group means an unsaturated group capable of undergoing radical polymerization. Examples of such polymerizable unsaturated groups include vinyl groups, (meth)acryloyl groups, (meth)acrylamide groups, vinyl ether groups, allyl groups, propenyl groups, isopropenyl groups, and maleimide groups.

"(Meth)acrylate" means acrylate or methacrylate, and "(meth)acrylic acid" means acrylic acid or methacrylic acid. "(Meth)acryloyl" means acryloyl or methacryloyl, and "(meth)acrylamide" means acrylamide or methacrylamide.

In the present invention, the hydrophilic monomer is at least one selected from alkoxy(meth)acrylates, hydroxyl group-containing polymerizable unsaturated monomers and carboxyl group-containing polymerizable unsaturated monomers.

Alkoxy (meth)acrylates include, for example, methoxyethyl (meth)acrylate, methoxypropyl (meth)acrylate, methoxybutyl (meth)acrylate and ethoxyethyl (meth)acrylate and combinations thereof.

Examples of hydroxyl group-containing polymerizable unsaturated monomers include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate, (meth)acrylic acid and dihydric alcohols having 2 to 8 carbon atoms, ε-caprolactone modified products of monoesterification, allyl alcohols, and (meth)acrylates having a polyoxyethylene chain with a hydroxyl group at the molecular end, and combinations thereof.

Carboxyl group-containing polymerizable unsaturated monomers include, for example, (meth)acrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, crotonic acid and β-carboxyethyl (meth)acrylate, and combinations thereof.

The copolymerization ratio of the hydrophilic monomer is 5% by mass or more, preferably in the range of 10 to 70% by mass, based on the total polymerizable unsaturated monomers used in the polymerization of the acrylic resin (A). When the copolymerization ratio of the hydrophilic monomer is within the above range, an effect of excellent antifouling performance can be obtained while the degree of renewal of the coating film is appropriate.

In the present invention, the hydrophilic monomer preferably contains alkoxy (meth) acrylate as a part of its component from the viewpoint of improving the antifouling property. When the hydrophilic monomer contains an alkoxy (meth) acrylate as part of its component, the content thereof is preferably 5 to 70% by mass of the total polymerizable unsaturated monomers used for polymerization of the acrylic resin (A), more preferably 10 to 60% by mass. By setting the content of the alkoxy (meth) acrylate within the above range, antifouling properties and crack resistance can be improved.

From the viewpoint of improving the antifouling property, the hydrophilic monomer preferably contains a carboxyl group-containing polymerizable unsaturated monomer, particularly (meth)acrylic acid, as part of its components. When the hydrophilic monomer contains a carboxyl group-containing polymerizable unsaturated monomer as a part of its component, the content in that case is preferably 0 to 13% by mass, more preferably 0 to 8% by mass, in the total polymerizable unsaturated monomer used for polymerization of the acrylic resin (A). By setting the content of the carboxyl group-containing polymerizable unsaturated monomer within the above range, antifouling properties and crack resistance can be improved.

On the other hand, the hydrophobic monomer is at least one selected from alkyl (meth)acrylates and aromatic vinyl compounds. Alkyl (meth)acrylates include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate and cyclohexyl (meth)acrylate and combinations thereof.

Aromatic vinyl compounds include, for example, styrene, vinyltoluene and α-methylstyrene, combinations thereof, and the like.

The copolymerization ratio of the hydrophobic monomer in the polymerizable unsaturated monomers used for polymerization of the acrylic resin (A) is preferably 95% by mass or less, more preferably in the range of 30 to 85% by mass. When the copolymerization ratio of the hydrophobic monomer is within the above range, there is an effect that the degree of renewal of the coating film is moderate and the antifouling performance is excellent.

The polymerizable unsaturated monomers for producing the acrylic resin (A) may optionally contain polymerizable unsaturated monomers other than the hydrophilic monomers and hydrophobic monomers. Examples of the other monomers include (meth)acrylates having a polyoxyethylene chain having an alkoxy group at one molecular end, (meth)acrylates having a polyoxypropylene chain having an alkoxy group at one molecular end, and alkylene glycol (meth)acrylate alkyl compounds such as propylene glycol monomethyl (meth)acrylate;
(meth)acrylonitrile, (meth)acrylamide, N,N-dimethyl(meth)acrylamide, (meth)acryloylmorpholine, N-isopropyl(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, N-alkoxymethyl(meth)acrylamide, N,N-dimethylaminoethyl(meth)acrylate, N,N-diethylaminoethyl(meth)acrylate, N,N-dimethylaminopropyl(meth)acrylamide, adducts of glycidyl(meth)acrylate and amine compounds, etc. a nitrogen-containing polymerizable unsaturated monomer;
Vinyl chloride; vinylidene chloride; (meth)acrylonitrile; vinyl acetate; butyl vinyl ether; lauryl vinyl ether; N-vinylpyrrolidone; vinyl propionate, vinyl compounds such as vinyl acetate; , 3,4-epoxycyclohexylpropyl (meth)acrylate, epoxy group-containing polymerizable unsaturated monomers such as allyl glycidyl ether; 2-(meth)acrylamido-2-methylpropanesulfonic acid, allylsulfonic acid, styrenesulfonic acid, sulfoethyl (meth)acrylate and their sodium salts or ammonium salts; phosphate group-containing polymerizable unsaturated monomers such as 2-(meth)acryloyloxyethyl acid phosphate; carbonyl group-containing polymerizable unsaturated monomers such as amides, acetoacetoxyethyl (meth)acrylates, vinyl alkyl ketones having 4 to 7 carbon atoms (e.g., vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone); and combinations thereof.

In the present invention, from the viewpoint of storage stability of the antifouling coating composition, the polymerizable unsaturated monomer component to be the copolymerization component of the acrylic resin (A) does not contain triisopropylsilyl (meth)acrylate. If the polymerizable unsaturated monomer component contains triisopropylsilyl (meth)acrylate, the antifouling coating composition of the present invention tends to increase in viscosity during storage, which is undesirable.

The solubility parameter (also referred to as "SP value") of the acrylic resin (A) is preferably 8.0 to 11.0, more preferably 8.5 to 10.5, in terms of storage stability, antifouling properties and crack resistance.

The glass transition temperature (also referred to as Tg) of the acrylic resin (A) is preferably 10 to 60°C, more preferably 20 to 50°C, from the viewpoint of storage stability, antifouling properties and crack resistance.

In the present invention, it is preferable to select the type and amount of the polymerizable unsaturated monomer component used in the polymerization of the acrylic resin (A) so that the solubility parameter and/or the glass transition temperature of the acrylic resin (A) are within the above ranges.

The solubility parameter generally represents a measure of the intermolecular interaction of liquid molecules, and various calculation methods are known for the SP value of a polymer. In this specification, the SP value of the acrylic resin (A) shall be obtained by calculating according to the following formula.
SP value= _SP1 * _fw1 + _SP2 * _fw2 +...+ _SPn * _fwn
In the above formula _, SP ₁ , SP _{2 , .}
Here, the SP value of the homopolymer of the polymerizable unsaturated monomer is the SP value obtained by turbidity point titration of a sample synthesized by adjusting the weight average molecular weight of the homopolymer to about 50,000.

The turbidity point titration method is known as one of methods capable of measuring the SP value of a polymer. W. Suh, J. M. Corbett:J. Apply Polym. Sci. , 12[10], p. 2359-2370 (1968).

In the present invention, 0.5 g of a sample from which volatile components have been removed by vacuum suction is weighed in a 100 ml beaker, 10 ml of acetone is added, and dissolved by a magnetic stirrer.
δ ₃ = (Vml ^1/2 · δml + Vmh ^1/2 · δmh) / (Vml ^1/2 + Vmh ^1/2 )
Vml, Vmh: drop amounts of poor solvent with low SP value and poor solvent with high SP value, respectively δml, δmh: SP value of poor solvent with low SP value and poor solvent with high SP value, respectively δ ₃ : SP value of sample Here, as the poor solvent, deionized water (SP value 23.4) is used as a high SP poor solvent, and n-hexane (SP value 7.3) is used as a low SP poor solvent.

Also, the glass transition temperature is calculated as follows.
1/Tg(K)= _W1 / _T1 + _W2 / _T2 +... _Wn / _Tn
Tg (°C) = Tg (K) - 273
In the formula, _{W 1} , W ₂ , . . . W _n are the mass fractions of each monomer, and T ₁ , T ₂ . The glass transition temperature of the homopolymer of each polymerizable unsaturated monomer is the static glass transition temperature when the homopolymer of the monomer is synthesized so as to have a weight average molecular weight of about 50,000.

The static glass transition temperature is determined by, for example, using a differential scanning calorimeter "DSC-50Q type" (manufactured by Shimadzu Corporation, trade name), using a sample from which volatile components have been removed by vacuum suction, measuring the change in the amount of heat in the range of -100 ° C. to +100 ° C. at a heating rate of 3 ° C./min, and observing the change point of the first baseline on the low temperature side.

The acrylic resin (A) is obtained, for example, by copolymerizing the polymerizable unsaturated monomers in the presence of a radical polymerization initiator. Examples of the radical polymerization initiator used in the above copolymerization reaction include azo compounds such as 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis-2-methylbutyronitrile, and dimethyl-2,2'-azobisisobutyrate; t-butyl peroxide compounds such as di-t-butyl peroxide, t-butyl peroxybenzoate, t-butyl peroxyisopropyl carbonate, t-butyl peroctoate, etc.; - t-amyl peroxide compounds such as di(t-amylperoxy)cyclohexane; t-hexylperoxide compounds such as t-hexylperoxy-2-ethylhexanoate, t-hexylperoxybenzoate, t-hexylperoxy-isopropyl monocarbonate, t-hexylperoxypivalate, and t-hexylperoxyneodecanoate. These polymerization initiators can be used alone or in combination of two or more.

Polymerization methods for obtaining the acrylic resin (A) include, for example, a solution polymerization method, a bulk polymerization method, an emulsion polymerization method, a suspension polymerization method, and the like. Among these, the solution polymerization method is particularly preferable in that the acrylic resin (A) can be synthesized easily and accurately.

In the above copolymerization reaction, an organic solvent may be used as a polymerization solvent, if necessary. Examples of such organic solvents include aromatic hydrocarbon solvents such as xylene and toluene; aliphatic hydrocarbon solvents such as hexane and heptane; ester solvents such as ethyl acetate, butyl acetate, isobutyl acetate and methoxypropyl acetate; alcohol solvents such as isopropyl alcohol and butyl alcohol;

The reaction temperature in the copolymerization reaction may be appropriately set according to the type of the polymerization initiator and the like, and is usually within the range of 70 to 160°C, preferably within the range of 80 to 140°C. The reaction time in the copolymerization reaction may be appropriately set according to the reaction temperature, the type of polymerization initiator, etc., and is usually about 4 to 8 hours.

In the present invention, the acrylic resin (A) may be any type of copolymer such as a random copolymer, a graft copolymer, a gradient structure type copolymer, or a block copolymer. The acrylic resin (A) preferably has a weight average molecular weight (Mw) of 1,000 to 150,000, particularly preferably 3,000 to 80,000, from the viewpoint of the antifouling properties of the coating film obtained from the antifouling coating composition.

In the present specification, the weight average molecular weight of the acrylic resin (A) is a value obtained by converting the retention time (retention volume) measured using a gel permeation chromatograph (GPC) into the molecular weight of polystyrene based on the retention time (retention volume) of standard polystyrene with a known molecular weight measured under the same conditions. Specifically, as a gel permeation chromatograph, "HLC8120GPC" (trade name, manufactured by Tosoh Corporation) is used, and as columns, "TSKgel G-4000HXL", "TSKgel G-3000HXL", "TSKgel G-2500HXL" and "TSKgel G-2000HXL" (trade names, both manufactured by Tosoh Corporation ) under the conditions of mobile phase tetrahydrofuran, measurement temperature of 40° C., flow rate of 1 mL/min, and detector RI.

The nonvolatile content of the acrylic resin (A) in the antifouling paint composition is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, and still more preferably 30 to 70% by mass, based on the nonvolatile content of the resin solid content (acrylic resin + rosin) in the antifouling paint composition, from the viewpoint of antifouling properties and crack resistance.

[Rosin compound (B)]
In addition, the antifouling paint composition of the present invention contains a rosin compound from the standpoint of antifouling properties. Rosin is a mixture of resin acids obtained from trees. Examples of resin acids include abietic acid, neoabietic acid, dehydroabietic acid, parastric acid, pimaric acid, isopimaric acid, sandaracopimaric acid, and levopimaric acid.

In the present invention, the rosin compound includes not only the above rosin but also rosin derivatives, rosin metal salts and the like.

Examples of the rosin derivative include hydrogenated rosin, unsaturated carboxylic acid-modified rosin obtained by reacting rosin with maleic acid, maleic anhydride, fumaric acid, and unsaturated carboxylic acid such as (meth)acrylic acid, and polymerized rosin obtained by polymerizing rosin. Examples of rosin metal salts include zinc rosinate, calcium rosinate, copper rosinate, magnesium rosinate, reaction products of other metal compounds and rosin, and the like.

The rosin-based compounds described above are not particularly limited, and may be used alone or in combination of two or more. When particularly high antifouling properties are required, use of rosin metal salts is preferred.

The nonvolatile content of the rosin-based compound (B) in the antifouling coating composition is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, and still more preferably 30 to 70% by mass, based on the nonvolatile content of the resin solid content (acrylic resin + rosin) in the antifouling coating composition, from the viewpoint of antifouling properties and crack resistance.

In the present invention, from the viewpoint of the storage stability of the antifouling coating composition, the long-term antifouling property of the coating film, and the crack resistance, the nonvolatile content mass ratio of the acrylic resin (A)/rosin compound (B) is within the range of 10/90 to 90/10, preferably within the range of 20/80 to 80/20.

[Medetomidine (C)]
The antifouling paint composition of the present invention contains medetomidine (C) from the viewpoint of achieving both storage stability and long-term antifouling properties. Medetomidine has the systematic name: (±)4-[1-(2,3-dimethylphenyl)ethyl]-1H-imidazole.

The content of medetomidine (C) is preferably 0.05 to 7% by mass, more preferably 0.05 to 3% by mass, based on the total non-volatile mass of the acrylic resin (A) and rosin compound (B).

[Antifouling agent]
In the present invention, other antifouling agents can be used in combination with medetomidine (C), if desired. Other antifouling agents include those conventionally known, such as inorganic compounds, organic compounds containing metals, and organic compounds containing no metals.

Examples of the inorganic compounds include cuprous oxide, copper powder, cuprous thiocyanate, copper carbonate, copper chloride, copper compounds such as copper sulfate; zinc compounds such as zinc sulfate and zinc oxide; nickel sulfate, copper-nickel compounds such as nickel alloys;

As the organic compound containing the metal, for example, an organic copper-based compound, an organic nickel-based compound, an organic zinc-based compound, and the like can be used. In addition, maneb, manceb, propineb, and the like can also be used.

Examples of the organic copper compounds include oxine copper, copper pyrithione, copper nonylphenolsulfonate, copper bis(ethylenediamine)-bis(dodecylbenzenesulfonate), copper acetate, copper naphthenate, and copper bis(pentachlorophenolate).

Examples of the organic nickel compounds include nickel acetate and nickel dimethyldithiocarbamate. Examples of the organic zinc compounds include zinc acetate, zinc carbamate, zinc dimethyldithiocarbamate, zinc pyrithione, and zinc ethylenebisdithiocarbamate.

Examples of the metal-free organic compounds include 4-bromo-2-(4-chlorophenyl)-5-(trifluoromethyl)-1H-pyrrole-3-carbonitrile (b2), N-trihalomethylthiophthalimide, dithiocarbamic acid, N-arylmaleimide, 3-substituted amino-1,3-thiazolidine-2,4-diones, dithiocyano-based compounds, and triazine-based compounds.

Examples of the N-trihalomethylthiophthalimide include N-trichloromethylthiophthalimide and N-fluorodichloromethylthiophthalimide. Examples of the dithiocarbamic acid include bis(dimethylthiocarbamoyl)disulfide, ammonium N-methyldithiocarbamate, ammonium ethylenebis(dithiocarbamate), Milneb and the like.

Examples of the N-arylmaleimide include N-(2,4,6-trichlorophenyl)maleimide, N-4-tolylmaleimide, N-3-chlorophenylmaleimide, N-(4-n-butylphenyl)maleimide, N-(anilinophenyl)maleimide, N-(2,3-xylyl)maleimide, 2,3-dichloro-N-(2',6'-diethylphenyl)maleimide, 2,3-dichloro-N- (2'-ethyl-6'-methylphenyl)maleimide and the like.

Examples of the 3-substituted amino-1,3-thiazolidine-2,4-dione include 3-benzylideneamino-1,3-thiazolidine-2,4-dione, 3-(4-methylbenzylideneamino)-1,3-thiazolidine-2,4-dione, 3-(2-hydroxybenzylideneamino)-1,3-thiazolidine-2,4-dione, and 3-(4-dimethylaminobenzylideneamino). -1,3-thiazoline-2,4-dione, 3-(2,4-dichlorobenzylideneamino)-1,3-thiazolidine-2,4-dione and the like.

Examples of the dithiocyano-based compounds include dithiocyanomethane, dithiocyanoethane, 2,5-dithiocyanothiophene, and the like. Examples of the triazine-based compound include 2-methylthio-4-t-butylamino-6-cyclopropylamino-s-triazine.

In addition to the above-exemplified organic compounds, examples of the metal-free organic compound include 2,4,5,6-tetrachloroisophthalonitrile, N,N-dimethyldichlorophenylurea, 4,5-dichloro-2-N-octyl-3-(2H)isothiazolone, N,N-dimethyl-N'-phenyl-(N-fluorodichloromethylthio)sulfamide, tetramethylthiuram disulfide, and 3-iodo-2-propynylbutyl. Carbamate, 2-(methoxycarbonylamino)benzimidazole, 2,3,5,6-tetrachloro-4-(methylsulfonyl)pyridine, diiodomethyl paratolyl sulfone, bisdimethyldithiocarbamoyl zinc ethylenebisdithiocarbamate, phenyl(bispyridine)bismuth dichloride, 2-(4-thiazolyl)benzimidazole, triphenylboronpyridine/amine complex, dichloro-N-((dimethylamino)sulfonyl) fluoro-N-(p-tolyl)methanesulfenamide, chloromethyl-n-octyl disulfide and the like.

As the other antifouling agent, it is preferable to use at least one selected from cuprous oxide, zinc oxide, copper pyrithione, and zinc pyrithione from the viewpoint of exhibiting particularly stable antifouling performance.

The total content when using these other antifouling agents is preferably 75 to 400% by mass, more preferably 100 to 375% by mass, based on the total non-volatile content of acrylic resin (A) and rosin compound (B) in the paint.

[Antifouling paint composition]
In addition to the acrylic resin (A), rosin-based compound (B), and medetomidine (C), the antifouling coating composition of the present invention may optionally contain various components used in general coating compositions, such as pigments, plasticizers, viscosity modifiers, antifoaming agents, antioxidants, resins other than the acrylic resin (A), and solvents. These components can be used individually or in combination of 2 or more types.

Examples of the pigment include coloring pigments such as red iron oxide, titanium oxide, yellow iron oxide, calcium oxide, carbon black, naphthol red, and phthalocyanine blue; extender pigments such as talc, silica, mica, clay, calcium carbonate, kaolin, alumina white, aluminum hydroxide, magnesium carbonate, barium carbonate, barium sulfate, and zinc sulfide; and combinations thereof.

The content of the pigment in the antifouling paint composition of the present invention is preferably in the range of 1 to 500% by mass, more preferably in the range of 5 to 350% by mass, based on the total amount of nonvolatile matter of the acrylic resin (A) and the rosin compound (B).

Examples of the plasticizer include tricresyl phosphate, dioctyl phthalate, chlorinated paraffin, liquid paraffin, n-paraffin, polybutene, terpenephenol, tricresyl phosphate (TCP) and polyvinyl ethyl ether, and combinations thereof.

When a plasticizer is added to the antifouling coating composition of the present invention, the content of the plasticizer is preferably 0.5 to 30% by mass, more preferably 1 to 20% by mass based on the mass of the acrylic resin (A).

Examples of the viscosity modifier include organic waxes (polyethylene wax, oxidized polyethylene wax, polyamide wax, amide wax, hydrogenated castor oil wax, etc.), organic clay compounds (amine salts of Al, Ca, Zn, stearate salts, lecithin salts, alkylsulfonates, etc.), bentonite, synthetic finely divided silica, and the like. These viscosity modifiers may be used singly or in combination of two or more.

When the viscosity modifier is blended in the antifouling paint composition, the content in that case is, for example, based on the total amount of acrylic resin (A) and rosin compound (B) nonvolatile matter, preferably 0.25 to 50% by mass, more preferably 0.3 to 20% by mass.

Examples of resins other than the acrylic resin (A) that are optionally blended in the antifouling coating composition of the present invention include resins having a metal carboxylate structure that are widely used as base resins for antifouling paints, acrylic silicone resins, epoxy resins, fluororesins, polybutene resins, silicone rubbers, urethane resins, polyamide resins, vinyl chloride copolymer resins, chlorinated rubbers, chlorinated olefin resins, styrene-butadiene copolymer resins, ketone resins, ethylene-vinyl acetate copolymer resins, vinyl chloride resins, alkyd resins, polyester resins, and cumarone resins. , terpene phenol resins, petroleum resins, and the like.

For the antifouling paint composition of the present invention, general organic solvents such as aliphatic solvents, aromatic solvents (e.g., xylene, toluene, etc.), ketone solvents (e.g., methyl isobutyl ketone, cyclohexanone, etc.), ester solvents, ether solvents (e.g., propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, etc.), alcohol solvents (e.g., isopropyl alcohol, etc.) can be used as solvents for antifouling paints. The amount of the organic solvent can be adjusted as appropriate. For example, the total non-volatile content of the antifouling paint composition is preferably in the range of 20 to 90% by mass, and may be further added during coating depending on the coating workability.

The antifouling paint composition of the present invention can be prepared by the same method as for known antifouling paint compositions. For example, acrylic resin (A), rosin-based compound (B), medetomidine (C), and if necessary, the additives, organic solvents, etc., are added to a stirring tank at once or sequentially, and stirred and mixed to produce.

The coated article of the present invention is an article obtained by coating the surface of a substrate with the antifouling coating composition of the present invention. The coated article is obtained by applying or impregnating the surface of the substrate with the antifouling coating composition one or more times, and drying the antifouling coating composition.

Examples of the substrate include substrates that are in contact with seawater or fresh water (e.g., constantly or intermittently), specifically, underwater structures, ship shells or ship bottoms, power plant water conduits and cooling pipes, fishing nets for aquaculture or stationary fishing nets, floats used for these, fishing net attachments such as ropes, and the like.

The film thickness of the coating film obtained from the antifouling coating composition of the present invention can be appropriately adjusted in consideration of the wear rate of the coating film, etc. For example, it is preferably about 30 to 250 μm/time, more preferably about 75 to 150 μm/time, and may be recoated two or more times as necessary.

In the present invention, the antifouling coating composition of the present invention may be applied by means of brush coating, spray coating, roller coating, immersion, or the like to the surface of the base material coated with a primer or anticorrosive coating and, if necessary, a binder coating. Moreover, the antifouling coating composition of the present invention may be overcoated on the surface of an existing antifouling coating film. The coating film can be dried at room temperature, but if necessary, it may be dried by heating at a temperature of up to about 100°C.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited only to the examples. "Parts" and "%" in the following examples mean "mass parts" and "mass%" respectively.

[Production of acrylic resin (A)]
Production example 1
After charging 40 parts of xylene into a flask equipped with a stirrer, the liquidus temperature was maintained at 100° C., and a mixed solution of 40 parts of methoxyethyl acrylate, 60 parts of methyl methacrylate, 68 parts of xylene, and 2.0 parts of azobisisobutyronitrile was dropped into the flask over 3 hours. After the dropwise addition was completed, the same temperature was maintained for 30 minutes. Then, a mixture of 10 parts of xylene and 1 part of "Perbutyl O" (trade name, manufactured by NOF Corporation, t-butyl peroxyoctoate) was added dropwise over 20 minutes, and the mixture was stirred at the same temperature for 2 hours, after which the liquid phase was cooled. A resin solution was prepared by adding xylene to the flask so that the nonvolatile content of the resin produced was 50% by mass, to obtain a resin solution of acrylic resin (A-1) having a weight average molecular weight of 50,000.

Production Examples 2-18
Resin solutions of acrylic resins (A-2) to (A-18) were obtained in the same manner as in Production Example 1 except that the amounts of the respective components were changed as shown in Table 1.

<Tg>
Tg was calculated by the following formula.
1/Tg(K)= _W1 / _T1 + _W2 / _T2 +... _Wn / _Tn
Tg (°C) = Tg (K) - 273
In the formula, _{W 1} , W ₂ , . . . W _n are the mass fractions of each monomer, and T ₁ , T ₂ . The glass transition temperature of the homopolymer of each polymerizable unsaturated monomer was the static glass transition temperature when the homopolymer of the monomer was synthesized so as to have a weight average molecular weight of about 50,000. The static glass transition temperature was measured using a differential scanning calorimeter "DSC-50Q" (manufactured by Shimadzu Corporation,
(trade name), and using a sample from which volatile components were removed by vacuum suction, the change in the amount of heat was measured in the range of -100 ° C. to +100 ° C. at a temperature increase rate of 3 ° C./min, and the first baseline on the low temperature side was determined by observing the change point.

<SP value>
The SP value of the acrylic resin (A) was calculated by the following formula.
SP value= _SP1 * _fw1 + _SP2 * _fw2 +...+ _SPn * _fwn
In the above formula _, SP ₁ , SP _{2 , .}
Here, the SP value of a homopolymer of a polymerizable unsaturated monomer is obtained by the turbidity point titration method [K. W. Suh, J.; M. Corbett:J. Apply Polym. Sci. , 12[10], p. 2359-2370 (1968)].

0.5 g of a sample from which volatile components were removed by vacuum suction was weighed in a 100 ml beaker, 10 ml of acetone was added, and dissolved with a magnetic stirrer. At a measurement temperature of 20 ° C., a high SP poor solvent or a low SP poor solvent was separately added dropwise to the solution.
δ ₃ = (Vml ^1/2 · δml + Vmh ^1/2 · δmh) / (Vml ^1/2 + Vmh ^1/2 )
Vml, Vmh: drop amounts of poor solvent with low SP value and poor solvent with high SP value, respectively δml, δmh: SP value of poor solvent with low SP value and poor solvent with high SP value, respectively δ ₃ : SP value of sample Here, as the poor solvent, ion-exchanged water (SP value 23.4) was used as a high SP poor solvent, and n-hexane (SP value 7.3) was used as a low SP poor solvent.

[Manufacture of antifouling paint composition]
Examples 1-34 and Comparative Examples 1-10
A resin solution of acrylic resins (A-1) to (A-18), a xylene solution of rosin, medetomidine (“selectope”: trade name, manufactured by I-Tech AB), an antifouling agent, titanium oxide, talc, chlorinated paraffin, etc. were blended according to the formulation shown in Tables 2-1 to 2-4, and mixed and dispersed using a homomixer at a stirring speed of about 2,000 rpm. After dispersion, "Disparlon A630-20XN" (Note: trade name, manufactured by Kusumoto Kasei Co., Ltd., polyamide wax, 20% xylene dilution) and xylene were added as a 20% viscosity modifier, and disper-stirred to prepare antifouling coating compositions (X-1) to (X-44). The prepared coating composition was subjected to the following storage stability test, antifouling performance test, wear film thickness and crack resistance test. The results of each of these tests are also shown in Tables 2-1 to 2-4.

<Storage stability test>
Each antifouling coating composition obtained in Examples and Comparative Examples was stored in a closed container at 40° C. for 12 months and evaluated according to the following criteria.
A: No change before and after storage.
◯: There is no problem in use, but there is a slight increase in viscosity.
Δ: Viscosity is increased to a degree that hinders use.
×: Separation.

<Anti-fouling performance test>
Both surfaces of a sandblasted steel plate (100 mm × 300 mm × 2 mm) were spray-coated with an epoxy rust preventive paint to a dry film thickness of 200 µm, and further epoxy-based binder coat was applied to a dry film thickness of 100 µm. Each antifouling paint composition was applied to both sides of the coated plate by spray coating four times so that the dry film thickness was 480 μm on one side, and dried in a constant humidity room at a temperature of 20 ° C. and a humidity of 75% for 1 week to prepare a test piece. Using this test piece, it was immersed in seawater for 24 months in Suruga Bay, Shizuoka Prefecture, and after 6 months, 12 months, and 24 months, the ratio of the area occupied by attached organisms on the test piece (adhesion area) was measured.
◎: Adhesive organisms were not observed,
○: The area occupied by attached organisms is less than 5%,
△: the area occupied by attached organisms is 5% or more and less than 30%,
x: The area occupied by adhering organisms is 30% or more.

<Consumable film thickness>
Each antifouling paint composition was applied to a blast plate that had been coated with an antifouling paint in advance so that the dry film thickness was 300 μm, and left in a room for two days and nights to dry to obtain a test plate having an antifouling paint film. This test plate was attached to the side surface of a cylinder with a diameter of 750 mm and a length of 1200 mm, and was continuously rotated in seawater at a peripheral speed of 15 knots for 12 months to measure the amount of coating film consumption (cumulative decrease in coating film thickness [μm]) of the test plate. The larger the numerical value of the "consumed film thickness" in Tables 2-1 to 2-4, the more the antifouling coating is consumed, indicating that the coating is renewed faster.

<Crack resistance test>
The coating film of the test piece subjected to the antifouling performance test was visually observed, and the presence or absence of cracks after 12 months and 24 months was examined.
◎: cracks were not observed,
○: fine cracks were observed in a part of the coating surface,
△: fine or clear cracks were observed in a wide range of the coating film surface,
x: Cracks reaching the substrate were observed.

As shown in Tables 2-1 to 2-3, the antifouling coating compositions of Examples 1 to 34 all exhibited excellent storage stability and antifouling properties, and also had good crack resistance. On the other hand, as shown in Table 2-4, Comparative Examples 1 to 10 all had lower antifouling performance than Examples. Comparative Examples 1 to 3 are examples in which the content of the hydrophilic monomer in the polymerizable unsaturated monomer component used for polymerization of the acrylic resin (A) is less than 5% by mass. Comparative Examples 4 to 6 are examples in which the antifouling coating composition does not contain medetomidine (C). Comparative Examples 7, 9 and 10 are examples in which the nonvolatile content mass ratio of acrylic resin (A)/rosin compound (B) is outside the range of 10/90 to 90/10.

Claims (8)

including acrylic resin (A), rosin-based compound (B) and medetomidine (C),
The acrylic resin (A) is a copolymer obtained by copolymerizing a polymerizable unsaturated monomer component containing a hydrophilic monomer and a hydrophobic monomer,
The hydrophilic monomer is at least one selected from alkoxy (meth) acrylates, hydroxyl group-containing polymerizable unsaturated monomers and carboxyl group-containing polymerizable unsaturated monomers,
The hydrophobic monomer is at least one selected from alkyl (meth)acrylates and aromatic vinyl compounds,
The polymerizable unsaturated monomer component does not contain triisopropylsilyl (meth)acrylate,
The copolymerization ratio of the hydrophilic monomer in the polymerizable unsaturated monomer used for polymerization of the acrylic resin (A) is 5% by mass or more,
An antifouling coating composition, wherein the acrylic resin (A)/rosin-based compound (B) has a non-volatile content mass ratio of 10/90 to 90/10. An antifouling coating composition according to claim 1, wherein said hydrophilic monomer comprises an alkoxy (meth)acrylate as part of its components. 3. An antifouling coating composition according to claim 1 or 2, wherein said hydrophilic monomer contains a carboxyl group-containing polymerizable unsaturated monomer as part of its components. The antifouling coating composition according to any one of claims 1 to 3, wherein the acrylic resin (A) has a solubility parameter in the range of 8.0 to 11.0. The antifouling coating composition according to any one of claims 1 to 4, wherein the acrylic resin (A) has a glass transition temperature in the range of 10 to 60°C. The antifouling coating composition according to any one of claims 1 to 5, wherein the rosin compound (B) is a rosin metal salt. The antifouling paint composition according to any one of claims 1 to 6, comprising at least one antifouling agent selected from cuprous oxide, zinc oxide, copper pyrithione and zinc pyrithione. A coated article having a coating film comprising the antifouling coating composition according to any one of claims 1 to 7.