Antifouling coating compositions, antifouling coating films, antifouling substrates, methods for producing antifouling substrates, and methods of storing antifouling coating compositions

Abstract

An antifouling coating composition contains a silyl ester (co)polymer and medetomidine and is used to prevent the fouling of substrates by aquatic organisms and which can form antifouling coating films exhibiting outstanding antifouling properties over a long period and also has good storage stability. The antifouling coating composition includes a silyl ester (co)polymer (A) and medetomidine (B), the silyl ester (co)polymer (A) including structural units derived from a monomer (a) represented by the general formula (I): R.sup.1CHC(CH.sub.3)COO(SiR.sup.2R.sup.3O).sub.nSiR.sup.4R.sup.5R.sup.6, and structural units derived from an unsaturated monomer (b) copolymerizable with the monomer (a).

Claims

1. An antifouling coating composition; comprising: a silyl ester (co)polymer (A) and medetomidine (B), wherein the silyl ester (co)polymer (A) comprises structural units derived from a monomer (a) represented by formula (I):
R.sup.1CHC(CH.sub.3)COO(SiR.sup.2R.sup.3O).sub.nSiR.sup.4R.sup.5R.sup.6(I) wherein R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are each independently a C.sub.1-20 monovalent organic group optionally having a heteroatom, R.sup.1 is a hydrogen atom or R.sup.7OCO; wherein R.sup.7 is a hydrogen atom, a C.sub.1-20 monovalent organic group optionally having a heteroatom, or a silyl group represented by R.sup.8R.sup.9R.sup.10Si, wherein R.sup.8, R.sup.9 and R.sup.10 are each independently a C.sub.1-20 monovalent organic group optionally having a heteroatom, and n is 0 or an integer of 1 or greater.

2. The antifouling coating composition according to claim 1, wherein the medetomidine (B) is present in a ratio of 0.01 to 50 parts by weight to 100 parts by weight of the silyl ester (co)polymer (A).

3. The antifouling coating composition according to claim 1, wherein the silyl ester (co)polymer (A) further comprises structural units derived from an unsaturated monomer (b) copolymerizable with the monomer (a).

4. The antifouling coating composition according to claim 3, wherein the unsaturated monomer (b) comprises at least one unsaturated monomer selected from the group consisting of an alkyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, an alkoxyalkyl (meth)acrylate, a hydroxyalkyl (meth)acrylate, a metal ester group-containing (meth)acrylate, an organosiloxane group-containing (meth)acrylate, and a monomer represented by formula (II):
R.sup.11CHCHCOO(SiR.sup.12R.sup.13O).sub.nSiR.sup.14R.sup.15R.sup.16(II) wherein R.sup.12, R.sup.13, R.sup.14, R.sup.15 and R.sup.16 are each independently a C.sub.1-20 monovalent organic group optionally having a heteroatom, R.sup.11 is a hydrogen atom or R.sup.17OCO wherein R.sup.17 is a hydrogen atom, a C.sub.1-20 monovalent organic group optionally having a heteroatom, or a silyl group represented by R.sup.18R.sup.19R.sup.20Si, wherein R.sup.18, R.sup.19 and R.sup.20 are each independently a C.sub.1-20 monovalent organic group optionally having a heteroatom, and n is 0 or an integer of 1 or greater.

5. The antifouling coating composition according to claim 1, wherein R.sup.4, R.sup.5 and R.sup.6 are all isopropyl groups.

6. The antifouling coating composition according to claim 1, further comprising an antifouling agent (C) other than the medetomidine (B).

7. The antifouling coating composition according to claim 6, wherein the antifouling agent (C) other than the medetomidine (B) is at least one antifouling agent selected from the group consisting of cuprous oxide, copper rhodanide, copper, copper pyrithione, zinc pyrithione, 4-bromo-2-(4-chlorophenyl)-5-(trifluoromethyl)-1H-pyrrole-3-carbonitrile, 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one, borane-nitrogen base adducts, N,N-dimethyl-N-(3,4-dichlorophenyl)urea, N-(2,4,6-trichlorophenyl)maleimide, 2-methylthio-4-tert-butylamino-6-cyclopropylamino-1,3,5-triazine, 2,4,5,6-tetrachloroisophthalonitrile, bisdimethyldithiocarbamoyl zinc ethylene bisdithiocarbamate, chloromethyl-n-octyl disulfide, N,N-dimethyl-N-phenyl-(N-fluorodichloromethylthio)sulfamide, tetraalkyl thiuram disulfides, zinc dimethyl dithiocarbamate, zinc ethylene bisdithiocarbamate, 2,3-dichloro-N-(2,6-diethylphenyl)maleimide and 2,3-dichloro-N-(2-ethyl-6-methylphenyl)maleimide.

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

9. The antifouling coating composition according to claim 8, wherein the dehydrating agent (D) is at least one selected from the group consisting of calcium sulfate, a hydrolyzable group-containing organosilane, a zeolite, alumina, silica and an orthoester.

10. The antifouling coating composition according to claim 1, further comprising a rosin (E).

11. The antifouling coating composition according to claim 1, which is a one pack coating.

12. An antifouling coating film formed from the antifouling coating composition of claim 1.

13. An antifouling substrate, comprising: a substrate and the antifouling coating film of claim 12 disposed on a surface of the substrate.

14. The antifouling substrate according to claim 13, which is placed in contact with seawater or freshwater.

15. The antifouling substrate according to claim 14, wherein the substrate is an underwater structure, outside shell of a ship or a fishing gear.

16. A method for producing an antifouling substrate, comprising: coating or impregnating a surface of a substrate with the antifouling coating composition of claim 1, and curing an antifouling coating coating or impregnating the substrate.

17. A method of storing an antifouling coating composition, comprising: charging the antifouling coating composition of claim 11 into a container and storing the antifouling coating composition.

18. A method for producing an antifouling substrate, comprising: forming a film from the antifouling coating composition of claim 1 and curing the film to form an antifouling coating film, and attaching the antifouling coating film onto a substrate.

Description

EXAMPLES

(1) Hereinbelow, the present invention will be described in greater detail based on Examples. However, the scope of the invention is not limited to such Examples.

Viscosity of Silyl Ester (Co)Polymer Solution

(2) The viscosity of a silyl ester (co)polymer solution at 25 C. was measured with a cone-plate viscometer (manufactured by TOKI SANGYO CO., LTD).

Concentration of Solid Content in Silyl Ester (Co)Polymer Solution

(3) The term solid content means a heating residue that is left when a reaction mixture, a coating, an uncured film or the like containing components such as resins and solvents is dried in a hot air dryer at 105 C. for 3 hours to evaporate volatiles such as solvents. The solid content are film-forming components which usually include resins and other components such as pigments.

Number Average Molecular Weight (Mn) and Weight Average Molecular Weight (Mw) of Silyl Ester (Co)Polymer

(4) The number average molecular weight (Mn) and weight average molecular weight (Mw) of a silyl ester (co)polymer were measured by GPC (gel permeation chromatography) under the following conditions.

GPC Conditions

(5) Apparatus: HLC-8120GPC (manufactured by TOSOH CORPORATION) Columns: Super H2000+ H4000 (manufactured by TOSOH CORPORATION, 6 mm (inner diameter), each 15 cm (length)) Eluent: tetrahydrofuran (THF) Flow rate: 0.500 ml/rain Detector: RI Column thermostatic chamber temperature: 40 C. Standard substance: polystyrene Sample preparation: The polymer solution prepared in each Production Example was dehydrated by the addition of a small amount of calcium chloride and was filtered through a membrane filter. The residue obtained was used as a GPC measurement sample.

[Production Example 1] Production of Silyl Ester Copolymer Solution (A-1)

(6) A reaction container equipped with a stirrer, a condenser, a thermometer, a dropping device, a nitrogen inlet tube and a heating/cooling jacket was loaded with 54 parts by weight of xylene and 70 parts by weight of triisopropylsilyl methacrylate. In a flow of nitrogen, the mixture was stirred while performing heating at a temperature of 85 C.5 C. While keeping the temperature, a mixture of 30 parts by weight of methyl methacrylate and 0.75 parts by weight of 2,2-azobis-2-methylbutyronitrile was dropped from the dropping device into the reaction container over a period of 2 hours. Thereafter, stirring was performed at the temperature for 4 hours, 0.4 parts by weight of 2,2-azobisisobutyronitrile was added, the resultant mixture was stirred at the temperature for 4 hours, and 26 parts of xylene was added. A colorless transparent silyl ester copolymer solution (A-1) was thus obtained.

(7) Table 1 describes the amounts of the monomer components used, and characteristic values of the solution (A-1) and the silyl ester copolymer present in the solution.

[Production Example 2] Production of Silyl Ester Copolymer Solution (A-2)

(8) A reaction container equipped with a stirrer, a condenser, a thermometer, a dropping device, a nitrogen inlet tube and a heating/cooling jacket was loaded with 54 parts by weight of xylene. In a flow of nitrogen, stirring was performed while performing heating at a temperature of 85 C.5 C. While keeping the temperature, a mixture of 55 parts by weight of triisopropylsilyl methacrylate, 30 parts by weight of 2-methoxyethyl methacrylate, 10 parts by weight of butyl acrylate, 5 parts by weight of methyl methacrylate and 0.65 parts by weight of 2,2-azobisisobutyronitrile was dropped from the dropping device into the reaction container over a period of 2 hours. Thereafter, stirring was performed at the temperature for 4 hours, 0.4 parts by weight, of 2,2-azobisisobutyronitrile was added, the resultant mixture was stirred at the temperature for 2 hours, and 14 parts by weight of xylene was added. A colorless transparent silyl ester copolymer solution (A-2) was thus obtained.

(9) Table 1 describes the amounts of the monomer components used, and characteristic values of the solution (A-2) and the silyl ester copolymer present in the solution.

[Production Examples 3 to 6] Production of Silyl Ester Copolymer Solutions (A-3) to (A-6)

(10) Silyl ester copolymer solutions (A-3) to (A-6) containing a silyl ester copolymer were prepared in the same manner as in Production Example 2, except that the mixture used in Production Example 2 was replaced by a mixture of the monomer components in the proportions shown in Table 1 and 2,2-azobisisobutyronitrile, and that the amounts of xylene and the polymerization catalyst (2,2-azobisisobutyronitrile) were adjusted appropriately.

(11) Table 1 describes the amounts of the monomer components used, and characteristic values of the solutions (A-3) to (A-6) and the silyl ester copolymers present in the solutions.

[Production Example 7] Production of Silyl Ester Copolymer Solution (A-7)

(12) A silyl ester copolymer solution (A-7) containing a silyl ester copolymer was prepared in the same manner as in Production Example 1, except that the triisopropylsilyl methacrylate was replaced by 70 parts by weight of triisopropylsilyl acrylate, and that the amounts of xylene and the polymerization catalysts (2,2-azobis-2-methylbutyronitrile and 2,2-azobisisobutyronitrile) were adjusted appropriately.

(13) Table 1 describes the amounts of the monomer components used, and characteristic values of the solution (A-7) and the silyl ester copolymer present in the solution.

(14) TABLE-US-00001 TABLE 1 Prod. Prod. Prod. Prod. Prod. Prod. Prod. Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Silyl ester copolymer solution A-1 A-2 A-3 A-4 A-5 A-6 A-7 Monomer Triisopropylsilyl methacrylate 70 55 40 55 60 55 components Triisopropylsilyl acrylate 20 70 2-Methoxyethyl methacrylate 30 30 30 2-Methoxyethyl acrylate 25 Butyl acrylate 10 5 10 Methyl methacrylate 30 5 30 20 15 5 30 Total 100 100 100 100 100 100 100 Characteristic Solid content (wt %) 55.9 59.9 55.8 60.1 60.3 60.6 55.4 values of silyl Viscosity (cps/25 C.) 1,563 2,164 2,360 2,701 1,842 1,052 1,539 ester Number average molecular weight 10,893 9,988 11,852 9,772 13,505 6,950 9,032 copolymers or (Mn) solutions Weight average molecular weight 44,878 47,902 40,070 48,320 42,318 22,533 40,266 thereof (Mw)

Examples 1 to 28 and Comparative Examples 1 to 4

Production of Antifouling Coating Compositions

(15) The components shown in Table 2, such as the solutions (A-1 to A-7) containing the silyl ester copolymers obtained in Production Examples 1 to 7, and medetomidine (B), were mixed together uniformly in the proportions described in Table 2 (the values in the table indicate parts by weight) with use of a paint shaker to give antifouling coating compositions. The compositions were evaluated by the following methods.

Storage Stability

(16) The antifouling coating compositions of Examples and Comparative Examples were each stored at 50 C. for 2 weeks, and the viscosity was compared to that, before the storage. The difference in viscosity value between before and after the storage was divided by the viscosity before the storage to calculate the viscosity increase ratio (%), based on which the storage stability of the antifouling coating composition was evaluated.

(17) The viscosity of the composition was measured at a temperature of 23 C. with a Stormer viscometer (manufacturer: TAIYU KIZAI K.K., product, name: STORMER VISCOMETER, model: 691).

Static Antifouling Properties of Coating Films

(18) An epoxy anticorrosive coating (epoxy AC coating, product name: BANNOH 500, manufactured by Chugoku Marine Paints, Ltd.) was applied onto a sandblasted steel sheet (300 mm in length100 mm in width3.2 mm in thickness) so that the dry thickness of the coating film would be 150 m. Thereafter, a vinyl binder coating (product name: SILVAX SQ-K, manufactured by Chugoku Marine Paints, Ltd.) was applied thereon so that the dry thickness of the coating film would be 40 m. Subsequently, any of the antifouling coating compositions produced in Examples was applied one time so that, its dry thickness would be 100 m. The wet film was dried at room temperature for 7 days. Test sheets having an antifouling coating film were thus fabricated. The above three coating operations took place at a rate of one operation per day.

(19) The test sheets fabricated as described above were immersed in Tokyo Bay under static conditions for three months in slimmer. The area of portions of the antifouling coating film fouled by barnacles (hereinafter, also written as the barnacle fouling area) was measured. The static antifouling properties of the antifouling coating film were evaluated in accordance with [Criteria in evaluation of static antifouling properties based on barnacle fouling area] below. The results are described in Table 2.

Criteria in Evaluation of Static Antifouling Properties Based on Barnacle Fouling Area

(20) 0: No barnacles had attached,

(21) 1: Barnacles had attached locally.

(22) 2: Barnacles had attached to the entire surface.

(23) TABLE-US-00002 TABLE 2 Examples 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Compositions of coatings (unit: parts by weight) A Copolymer solution A-1 20 20 (55.9% solid) Copolymer solution A-2 20 20 20 20 20 20 20 15 25 (59.9% solid) Copolymer solution A-3 20 (55.8% solid) Copolymer solution A-4 20 20 (60.1% solid) Copolymer solution A-5 20 (60.3% solid) Copolymer solution A-6 20 (60.6% solid) Copolymer solution A-7 (55.4% solid) Acrylic resin BR-106 (*1) B Medetomidine 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.3 0.5 0.1 0.1 0.1 0.1 0.1 0.1 C Cuprous oxide 1 (*2) 45 45 45 45 45 45 45 45 45 45 45 45 45 45 45 45 Cuprous oxide 2 (*3) 4,5-Dichloro-2-n-octyl-4- 3 isothiazolin-3-one (30% solid) Zinc 3 dimethyldithiocarbonate Copper pyrithione 3 3 3 3 3 3 3 3 3 3 3 3 3 3 Copper rhodanide Zinc pyrithione Pyridine triphenylborane D Calcium sulfate anhydride 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Ethyl Silicate 28 (*4) 0.5 E Rosin (50% solid) F Trimethylisobutenylcyclo- 10 10 10 10 10 10 10 10 10 10 10 10 10 15 5 hexenecarboxylic acid (50% solid) (*5) Zinc oxide 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 Red iron oxide 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 Oxidized polyethylene wax 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 (20% solid) Fatty acid amide wax 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 (20% solid) Xylene 10.9 10.9 10.9 10.9 10.9 10.9 10.9 10.9 10.9 10.9 10.9 10.9 10.9 10.9 10.9 10.9 Propylene glycol 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 monomethyl ether Total 101 102 102 102 102 91.5 102 102 102 102 102 102 102 101 102 102 Properties of coatings and coating films Storage stability 11% 8% 6% 6% 10% 12% 6% 6% 10% 19% 4% 8% 4% 10% 6% 6% (viscosity increase ratio (%)) Antifouling properties 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Examples Comparative Examples 17 18 19 20 21 22 23 24 25 26 27 28 1 2 3 4 Compositions of coatings (unit: parts by weight) A Copolymer solution A-1 (55.9% solid) Copolymer solution A-2 20 15 22 20 20 20 20 20 20 20 20 (59.9% solid) Copolymer solution A-3 20 (55.8% solid) Copolymer solution A-4 20 (60.1% solid) Copolymer solution A-5 (60.3% solid) Copolymer solution A-6 (60.6% solid) Copolymer solution A-7 20 20 (55.4% solid) Acrylic resin BR-106 (*1) 20 B Medetomidine 0.1 0.1 0.1 0.3 0.3 0.3 0.3 0.3 0.3 0.1 0.1 0.1 0.1 0.1 C Cuprous oxide 1 (*2) 45 45 45 45 45 45 45 45 45 45 45 Cuprous oxide 2 (*3) 45 4,5-Dichloro-2-n-octyl-4- 3 isothiazolin-3-one (30% solid) Zinc dimethyldithiocarbonate Copper pyrithione 3 3 3 3 3 3 3 3 3 3 3 3 3 Copper rhodanide 30 Zinc pyrithione 10 Pyridine triphenylborane 5 D Calcium sulfate anhydride 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Ethyl Silicate 28 (*4) E Rosin (50% solid) 10 15 8 10 0.3 10 10 F Trimethylisobutenylcyclo- 10 10 10 10 10 10 10 10 10 10 hexenecarboxylic acid (50% solid) (*5) Zinc oxide 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 Red iron oxide 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 Oxidized polyethylene wax 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 (20% solid) Fatty acid amide wax 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 (20% solid) Xylene 10.9 10.9 10.9 10.9 10.9 10.9 10.9 10.9 10.9 10.9 10.9 10.9 10.9 10.9 10.9 10.9 Propylene glycol 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 monomethyl ether Total 102 102 102 102 102 53.7 86.7 63.7 61.7 102 102 102 101 101 101 101 Properties of coatings and coating films Storage stability 6% 5% 6% 8% 8% 9% 10% 11% 13% 5% 6% 7% 0% >100% 0% 0% (viscosity increase ratio (%)) Antifouling properties 0 0 0 0 0 0 0 0 0 0 0 0 2 0 1 2 (*1) Dianal BR-106 (MITSUBISHI RAYON CO., LTD.), (*2) NC-301 (NISSIN CHEMCO LTD.), (*3) Purple copp 2A (American Chemet Corp), (*4) Ethyl Silicate 28 (COLCOAT CO., LTD.), (*5) Reaction product of 2,6-dimethylocta-2,4,6-triene with methacrylic acid, based on 1,2,3-trimethyl-5-(2-methylprop-1-en-1-yl)cyclohex-3-ene-1-carboxylic acid and 1,4,5-trimethyl-2-(2-methylprop-1-en-1-yl)cyclohex-3-ene-1-carboxylic acid