GB2084167A

GB2084167A - Antifouling paint compositions

Info

Publication number: GB2084167A
Application number: GB8126134A
Authority: GB
Original assignee: Nippon Oil and Fats Co Ltd
Current assignee: NOF Corp
Priority date: 1980-09-10
Filing date: 1981-08-27
Publication date: 1982-04-07
Also published as: JPS6333513B2; JPS5749675A; GB2084167B; NO812903L

Abstract

Antifouling paint compositions which do not form cracks in the coated film comprise a copolymer consisting of an organic tin-containing repeating unit (a) shown by the general formula <IMAGE> and/or <IMAGE> wherein R is an alkyl, cycloalkyl or phenyl group having 1-8 carbon atoms and X and Y are hydrogen atom or methyl group, and at least one monomer repeating unit (b) selected from acrylic compounds, vinyl compounds having functional group and vinyl hydrocarbons as a vehicle, cuprous oxide as an anti- fouling agent and insoluble or difficulty soluble platy, prismatic or needle-like inorganic or organic compounds or a combination of these compounds, as a crack preventing agent.

Description

SPECIFICATION Antifouling paint compositions The present invention relates to antifouling paint compositions containing an organic tincontaining copolymer as a vehicle, cuprous oxide as an antifouling agent and a platy, prismatic or needle-like inorganic or organic compound as an internal stress decreasing agent for preventing formation of cracks which are the defect of coated film.

Ships and marine structures are fouled by depositing of marine animals or plants and subjected to various damages. Concerning ships, the friction resistance of ship boards is increased and the ship velocity is lowered and the consumed fuel is increased and therefore the economical loss is large. Therefore, an antifouling paint is coated to prevent the depositing of marine organisms.

Recently, soluble matrix type antifouling paints in which an organic tin is bonded in a resin used as a vehicle of such a paint and the organic tin is dissociated in seawater to prevent the depositing of marine organisms and concurrently dissolve the resin, have been disclosed in Japanese Patent No. 471,072, No. 557,537 and No. 838,433 and noticed.

Furthermore, it has been disclosed in British Patent No. 1,124,297 that cuprous oxide is incorporated in the paint as an antifouling agent which is used together with the polymer, inorder to increase the antifouling activity.

However, when the antifouling paints wherein coprous oxide is incorporated together with the copolymer as the antifouling agent, are submerged in seawater, cracks are formed on the coated film surface as a coating defect. This is because the coated film formed of the paint compounding the above decribed polymer as a vehicle and cuprous oxide as an antifouling agent shows a larger shrinking stress due to the intrinsic property of said polymers and the presence of cuprous oxide of a spheric pigment than the coated film formed of prior insoluble matrix type antifouling paints and cracks, that is the coating defect referred to as "crocodile" are caused and the depth thereof becomes from about 10 lim to several hundred ym. The soluble matrix type antifouling paints can expect the merit which decreases the surface roughness at the bottom portion of ship external board, that is self-polishing cleaning ability but the antifouling paint containing cuprous oxide together with the copolymer as the antifouling agent forms cracks, whereby the friction resistance of the ship external board is disadvantageously increased.For improving this defect, the inventors have made diligent study and found that when platy, prismatic or needle-like inorganic or organic compounds which are insoluble or difficultly soluble, or a combination of these compounds are incorporated in the paint, the shrinkage of the coated film when a solvent in the antifouling paint is volatilized or the coated fim is submerged in seawater and then exposed to air and dried, is restrained and the shrinking stress is reduced and the formation of cracks or crocodile on the coated film surface formed of the antifouling paint is prevented.

The present invention consists in antifouling paint compositions comprising copolymers consisting of an organic tin-containing repeating unit (a) shown by the general formula

and/or

wherein R is an alkyl, cycloalkyl or phenyl group having 1-8 carbon atoms and X and Y are hydrogen atom or methyl group, and at least one monomer repeating unit (b) selected from the group consisting of acrylic compounds, vinyl compounds and vinyl hydrocarbons having functional groups as a vehicle, cuprous oxide as an antifouling agent and insoluble or difficultly soluble platy, prismatic or needle-like inorganic or organic compounds or a combination of these compounds, which decreases the internal stress in the coated film which is necessarily formed after formation of the coated film to prevent generation of the coated film defect, such as cracks, a weight ratio of the vehicle to cuprous oxide being 1:1-1:5 and the above described compound or the combination thereof being contained in an amount of 1-30% by weight.

The organic tin-containing copolymers to be used in the present invention have an organic tincontaining repeating unit (a) shown by the general formula

at least one monomer repeating unit (b) selected from the group consisting of acrylic compounds, vinyl compounds having functional groups and vinyl hydrocarbons.As the organic tin compounds shown by the above described general formula (I), mention may be made of bis(tributyltin) maleate, bis(triphenyltin) maleate, bis(tri-n-octyltin) maleate, bis(tri-n-hexyltin) maleate, bis(tricyclohexyltin) maleate, bis(tributyltin) fumarate, bis(triphenyltin) fumarate, bis(trin-octyitin) fumarate, bis (tri-n-hexyltin) fumarate, bis(tricyclohexyltin) fumarate, bis(tributyltin) citraconate, bis(trihenyltin) citraconate, bis(tri-n-octyltin) citraconate, bis(tricyclohexyltin) citraconate, bis(tributyltin) mesaconate, bis(triphenyltin) mesaconate, bis(tri-n-octyltin) mesaconate, bis(tricyclohexyltin) mesaconate, etc.

As the organic tin compounds shown by the above described general formula (II), mention may be made of tri-n-butyltin acrylate, tri-n-propyltin acrylate, triisopropyltin acrylate, tri-secbutyltin acrylate, triethylti n acrylate, diamethyltin acrylate, triphenyltin acrylate, diethylhexyltin acrylate, polybutylamyltin acrylate, diethylphenyltin acrylate, n-octyldiphenyltin acrylate, diethyloctyltin acrylate, tri-n-butyltin methacrylate, tri-n-propyltin methacrylate, triisopropyltin methacrylate, tri-sec-butyltin methacrylate, triethyltin methacrylate, diethylbutyltin methacrylate, diethylamyltin methacrylate, diamylmethyltin methacrylate, propylbutylamyltin methacrylate, diethylhexyltin methacrylate, triphenyltin methacrylate, diethylphenyltin methacrylate, ethyldiphenyltin methacrylate, n-octyldiphenyltin methacrylate, diethyloctylin methacrylate, etc.

As acrylic compounds of the monomers (b) to be copolymerized with these tri-organic tin compounds, mention may be made of methyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, ethyl acrylate, butyl acrylate, octyl acrylate, cyclohexyl acrylate, dodecyl acrylate, phenyl acrylate and the like.

As the vinyl compounds having functional groups as the monomers (b), mention may be made of vinyl chloride, vinylidene chloride, acrylonitrile, methacrylonitrile, vinyl acetate, vinyl butyrate, butyl vinyl ether, octyl vinyl ether, dodecyl vinyl ether, lauryl vinyl ether, etc. As the vinyl hydrocarbons as the monomers (b), mention may be made of ethylene, butadiene, styrene, etc. These monomers may be used alone or in combination of two or more monomers.

Insoluble or difficultly soluble platy, prismatic or needle-like inorganic compounds used in the present invention include, for example, mica, micaceous iron oxide, china clay, gypsum, asbestos, copper powder, tin flake, silver nitrate, barium oxalate, molybdenum (Ill) bromide, nickel dimethyl glyoxime and the like.

As insoluble or difficultly soluble platy, prismatic or needle-like organic compounds to be used in the present invention, mention may be made of triphenyltin hydroxide, triphenyltin chloride, triphenyltin fluoride, triphenyltin acetate, bis(triphenyltin) a,cw'-dibromosuccinate, bistriphenyltin oxide, triphenyltin nicotinate, triphenyltin versatate, triphenyltin dimethyldithiocarbamate, tributyltin fluoride, 2,4,-dichlorophenoxyacetate, 6-chloro-N, N'-diethyl- 1,3, 5,triazine-2,4-diamine, (3 chlorophenyl) carbamate-4-chloro-2-butyl ether, 2,4, 5,6-tetrachloro-l ,3-benzene dicarbonitrile, etc.

The mixture ratio by weight of the vehicle to cuprous oxide to be used in the paint of the present invention is from 1:1 to 1: 5 and when the ratio is beyond this range, the fundamental properties as the antifouling paint cannot be maintained.

The content of the above described inorganic or organic compounds in the antifouling paints is 1-30% by weight, preferably 2-10% by weight. When this content is less than 1% by weight, the desired object of the present invention cannot be attained and when this content exceeds 30% by weight, the coating film forming ability is deteriorated and the object of the present invention cannot be attained.

In addition to the above described copolymers, cuprous oxide, the crack preventing agent to be used in the present invention, conventional additives, for example, solvents for the paints, such as xylene, toluene, isopropyl alcohol, butyl alcohol, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, ethyl cellosolve, etc.; inorganic or organic pigments, such as red iron oxide, carbon black, titanium oxide, phthalocyanine blue, carmine red, etc.; thiazole dye stuffs, azo dye stuffs; precipitation preventing agents; antisagging agents; levelling agents; color separation preventing agents and the like may be together used.

The antifouling paint compositions according to the present invention may be prepared by already known processes.

An explanation is made with respect to production of the copolymers for the vehicle which can be used in practice of the present invention.

Reference Example 1 Homopolymer of tributyltin methacrylate is produced as follows. 79 g of tributyltin methacrylate was dissolved in 40 ml of benzene and 0.4 g of benzoyl peroxide was added to the resulting solution and the mixture was maintained at 60"C for 6 hours under stirring to effect the polymerization reaction. The reaction product was a colourless viscous solution having 210 cps (25 C). This polymer was soluble in benzene, butanol, methyl isobutyl ketone and tricrene and was insoluble in methanol, acetone and petroleum benzine.

Reference Example 2 Copolymer of tri-n-butyltin methacrylate, methyl methacrylate, n-butyl acrylate and n-octyl acrylate is produced as follows. A mixture of 11 2 g of tri-n-butyltin methacrylate, 65 g of methyl methacrylate, 10 g of n-butyl acrylate, 23 g of n-octyl acrylate, 1.2 g of benzoyl peroxide and 200 g of xylene was heated at a temperature of 85-90"C for 2 hours, at a temperature of 100-105"C for 3 hours and then at 120"C for 1 hour to effect polymerization.

The resulting solution of the organic tin-containing copolymer in xylene is colourless and transparent and has a viscosity of 660 cps at 25"C.

Reference Example 3 A copolymer of tricyclohexyltin methacrylate, tri-n-butyltin methacrylate, methyl methacrylate and tri-n-butyl acrylate is produced as follows.

A mixture of 60 g of tricyclohexyltin methacrylate, 60 g of tri-n-butyltin methacrylate, 90 g of methyl methacrylate, 90 g of n-butyl acrylate, 1.5 g of azobisisobutyronitrile and 300 g of xylene was heated at a temperature of 75-80"C for 6 hours to effect polymerization. The resulting xylene solution of the organic tin-containing copolymer is colourless and slightly muddy and has a viscosity of 810 cps (25do).

Reference Example 4 A copolymer of bis(triphenyltin) maleate, methyl methacrylate, styrene and vinyl acetate is produced as follows.

A mixture of 12.0 g of maleic anhydride, 40 g of methyl methacrylate, 30 g of styrene, 20 g of vinyl acetate, 1.0 g of benzoyl peroxide, 90 g of xylene and 10 g of methyl isobutyl ketone was heated at a temperature of 90-95"C for 7 hours and then at 120"C for 1 hour to effect polymerization. To the obtained copolymer (1,000 cps, 25"C) were added 88.1 g of bis(triphenyltin) oxide and 100 g of xylene and the mixture was reacted at 90"C for 1 hour. The thus obtained organic tin-containing copolymer is colourless and slightly muddy and has a viscosity of 325 cps (25"C).

The invention is explained with reference to the following Examples hereinafter % means by weight unless it is stated otherwise.

Example 1 Mica 7.0% Red iron oxide 5.0% Cuprous oxide 50.0% Tributyltin methacrylate/methyl methacrylate/octyl acrylate copolymer (weight average molecular weight about 45,000) 15.0% Disparon &num;4300* 5.0% Xylene 18.0% 100.0% Note: *Anti-sagging agent, trademark, made by Kusumoto Kasei Co., Ltd.

These components were mixed and dispersed in a ball mill for 5 hours to prepare a paint. In the following Examples and Comparative Examples, the paints were prepared in the same manner as described above.

Example 2 Micaceous iron oxide 8.0% Red iron oxide 10.0% Cuprous oxide 30.0% Triphenyltin methacrylate/butyl acrylate copolymer (weight average molecular weight about 50,000 20.0% Disparon &num;4300 5.0% Xylene 27.0% 100.0% Example 3 China clay 9.0% Red iron oxide 8.0% Cuprous oxide 40.0% Bis(triphenyltin) maleate/styrene/vinyl acetate copolymer (weight average molecular weight about 55,000) 20.0% Disparon &num;;4400-25x (made by Kusumoto Kasei K.K.) 6.0% Xylene 17.0% 100.0% Example 4 Gypsum 7.0% Red iron oxide 9.0% Cuprous oxide 45.0% Bis(triphenyltin) maleate/vinyl acetate/methyl methacrylate copolymer (weight average molecular weight about 55,000) 15.0% Disparon &num;4400-25x 6.0% Xylene 18.0% 100.0% Example 5 Asbestos 6.0% Red iron oxide 8.0% Curpous oxide 40.0% Tributyltin methacrylate/ethyl acrylate/methyl methacrylate copolymer (weight average molecular weight about 50,000) 20.0% Disparon &num;;4300 5.0% Xylene 21.0% 100.0% Example 6 Copper powder 20.0% Red iron oxide 7.0% Cuprous oxide 35.0% Triphenyltin acrylate/ethylhexyl acrylate/butyl methacrylate/ethyl acrylate copolymer (weight average molecular weight about 50,000) 20.0% Disparon &num;4300 1.0% Xylene 17.0% 100.0% Example 7 Tin flake 15.0% Red iron oxide 8.0% Cuprous oxide 25.0% Bis(tributyltin) maleate/hexyl acrylate copolymer (weight average molecular weight about 55,000) 25.0% Disparon &num; ;4400-25x 6.0% Xylene 21.0% 100.0% Example 8 Triphenyltin hydroxide 9.0% Red iron oxide 8.0% Cuprous oxide 50.0% Bis(tricyclohexyltin) maleate/ triphenyltin methacrylate/n-octyl acrylate/butyl methacrylate copolymer (weight average molecular weight about 60,000) 13.0% Disparon &num;4400-25x 3.0% Xylene 17.0% 100.0% Example 9 Triphenyltin chloride 30.0% Red iron oxide 10.0% Cuprous oxide 19.0% Tricyclohexyltin methacrylate/ tributyltin methacrylate/methyl methacrylate/butyl acrylate copolymer (weight average molecular weight about 50,000) 19.0% Disparon &num;;4300 5.0% Xylene 17.0% 100.0% Example 10 Triphenyltin fluoride 7.0% Red iron oxide 5.0% Cuprous oxide 50.0% Triphenyltin acrylate/tributyltin methacrylate/ethylhexyl acrylate copolymer (weight average molecular weight about 50,000) 20.0% Disparon &num;4300 1.0% Xylene 17.0% 100.0% Example 11 Triphenyltin acetate 8.0% Red iron oxide 10.0% Cuprous oxide 42.0% Tributyltin methacrylate/ styrene/ethyl methacrylate copolymer (weight average molecular weight about 50,000) 12.0% Disparon &num;;4300 5.0% Xylene 23.0% 100.0% Example 12 Bis(triphenyltin) a,a'-dibromoscuccinate 9.0% Red iron oxide 5.0% Cuprous oxide 35.0% Bis(triethyltin) maleate/ethylhexyl acrylate/ethyl acrylate copolymer (weight average molecular weight about 55,000) 30.0% Disparon &num;4400-25x 3.0% Xylene 18.0% 100.0% Example 13 Bis(triphenyltin) oxide 20.0% Red iron oxide 8.0% Cuprous oxide 35.0% Tributyltin acrylate/ethyl acrylate/hexyl methacrylate copolymer (weight average molecular weight about 55,000) 15.0% Disparon &num;;300 5.0% Xylene 17.0% 100.0% Example 14 Triphenyltin nicotinate 15.0% Red iron oxide 8.0% Cuprous oxide 40.0% Triethyltin methacrylate/methyl methacrylate/styrene copolymer (weight average molecular weight about 50,000) 20.0% Disparon &num;4300 5.0% Xylene 12.0% 100.0% Example 15 Triphenyltin versatate 8.0% Red iron oxide 8.0% Cuprous oxide 50.0% Tributyltin methacrylate/styrene/ methyl methacrylate copolymer (weight average molecular weight about 50,000) 15.0% Disparon &num;;4300 5.0% Xylene 14.0% 100.0% Example 16 Triphenyltin dimethyl dithiocarbamate 20.0% Red iron oxide 5.0% Cuprous oxide 30.0% Triphenyltin methacrylate/butyl acrylate/methyl methacrylate/ethyl acrylate copolymer (weight average molecular weight about 55,000) 25.0% Disparon &num;4300 2.0% Xylene 18.0% 100.0% Example 17 Tributyltin fluoride 10.0% Red iron oxide 5.0% Cuprous oxide 45.0% Triphenyltin methacrylate/n-octyl methacrylate/ethyl acrylate copolymer (weight average molecular weight about 50,000) 20.0% Disparon &num;;4300 1.0% Xylene 19.0% 100.0% Example 18 2,4-dichlorophenoxyacetate 9.0% Red iron oxide 8.0% Cuprous oxide 50.0% Bis(tripropyltin) maleate/butyl methacrylate/styrene copolymer (weight average molecular weight about 60,000) 15.0% Disparon 4400-25x 6.0% Xylene 12.0% 100.0% Example 19 6-chloro-N,N'-diethyl-1 ,3,5- triazine-2,4-diamine 15.0% Red iron oxide 8.0% Cuprous oxide 35.0% Bis(triphenyltin) maleate/ethylhexyl acrylate/methyl methacrylate copolymer (weight average molecular weight about 60,000) 20.0% Disparon &num;;4400-25x 3.0% Xylene 19.0% 100.0% Example 20 (3-chlorophenyl) carbamate-4chloro-2-butyl ether 10.0% Red iron oxide 4.0% Cuprous oxide 40.0% Tributyltin acrylate/ethyl acrylate/butyl methacrylate copolymer (weight average molecular weight about 50,000) 25.0% Disparon &num;4300 1.0% Xylene 20.0% 100.0% Example 21 2,4,5,6-tetrachloro-1 ,3-benzene dicarbonitrile 15.0% Red iron oxide 8.0% Cuprous oxide 30.0% Triisopropyltin acrylate/ triethyltin methacrylate/ butyl methacrylate copolymer (weight average molecular weight about 55,000) 25.0% Disparon &num;;4300 5.0% Xylene 17.0% 100.0% Example 22 Triphenyltin fluoride 10.0% Mica 5.0% Titanium dioxide 3.0% Cuprous oxide 30.0% Tributyltin acrylate/triethyltin methacrylate/butyl methacrylate copolymer (weight average molecular weight about 45,000) 30.0% Disparon &num;4300 5.0% Xylene 13.0% Methyl isobutyl ketone 4.0% 100.0% Example 23 Bis(triphenyltin) a,a'dibromosuccinate 7.0% Barium oxalate 7.0% Carbon black 3.0% Cuprous oxide 35.0% Triphenyltin methacrylate/ tributyltin acrylate/methyl methacrylate copolymer (weight average molecular weight about 50,000) 25.0% Disparon &num;;4400-25x 10.0% Isopropyl alcohol 3.0% Xylene 8.0% Ethyl cellosolve 2.0% 100.0% Example 24 Tin flake 10.0% Micaceous iron oxide 1.0% Phthalocyanine blue 1.0% Titanium dioxide 3.0% Cuprous oxide 40.0% Tri-n-propyltin acrylate/methyl methcarylate copolymer (weight average molecular weight about 60,000) 20.0% Disparon &num;;4300 5.0% Methyl ethyl ketone 10.0% Xylene 10.0% 100.0% Comparative Example I Red iron oxide 5.0% Cuprous oxide 35.0% Tributyltin acrylate/methyl methacrylate/butyl acrylate copolymer (weight average molecular weight about 50,000) 35.0% Disparon 4*4300 2.0% Xylene 23.0% 100.0% Comparative Example 2 Red iron oxide 5.0% Cuprous oxide 50.0% Tricyclohexyltin methacrylate/ styrene/butyl acrylate copolymer (weight average molecular weight about 55,000) 20.0% Disparon &num;4300 5.0% Xylene 20.0% 100.0% Comparative Example 3 Red iron oxide 5.0% Cuprous oxide 60.0% Bis(tributyltin) maleate/butyl methacrylate copolymer (weight average molecular weight about 60,000) 12.0% Disparon &num;;4400-25x 3.0% Xylene 20.0% 100.0% A wash primer was coated on a sand blast treated steel sheet of 250 x 250 x 2.5 mm and then a commercially available anticorrosive paint was coated thereon three times. Then, antifouling paints of the above described Examples 1-24 and Comparative Examples 1-3 were respectively coated with air spray theeon three times. Thereafter, the test plates were suspended from a raft and submerged in seawater at Yura Bay, Sumoto City, Hyogo Prefecture, Japan for 3 months and exposed in air at an angle of 45 facing south for 1 month. This test was made in 3 cycles and then the state of the coated films was inspected. In addition, after coating, the internal shrinking stress of each coated film was measured as follows.

Since the coated film is curved in a circular arc form on one surface of the metal piece due to the shrinkage of the uniform coated film, a distortion 8 at the central portion of the piece was read by a microscope. The curvature radius p is shown by the following equation.

12 6 12 p = + - 88 2 88 I: length of the coated film piece.

The obtained p is substituted in the following equation and the internal shrinking stress P is calculated.

E2bh22 1 P = - F(m,n).

12bh, pH In the above equation, b is a breadth of the coated piece, h1 is a thickness of the coated film, h2 is a thickness of the metal piece and E2 is Young's modulus of the metal piece.

E1 h1 m = -, n =, H = h, + h2 E2 h2 (1 - mn2)(1 - m) + {mn(n + 2) + 1}3 + m(mn2 + 2n + 1)3 F(m,n)= (1 + mn)3 E,: Young's modulus of the coated film.

The obtained results are shown in the following Table 1. The surface roughness of the test plate was measured following to JIS B0601-1976. The obtained results are shown in the following Table 2.

Talble 1(a)

Coated film surface state *) Internal After After After after After After shrinking second second third third Sample submerging exposing stress submerging exposing submerging exposing (kg/cm2) After After After After After After 3 months 4 months 7 months 8 months 11 months 12 months Example 1 7 5 5 5 5 5 5 2 6 5 5 5 5 5 5 3 7 5 5 5 5 5 5 4 7 5 5 5 5 5 5 5 6 5 5 5 5 5 5 6 8 5 5 5 5 5 5 7 7 5 5 5 5 5 5 8 6 5 5 5 5 5 5 9 2 5 5 5 5 5 5 10 8 5 5 5 5 5 5 11 5 5 5 5 5 5 5 12 6 5 5 5 5 5 5 13 4 5 5 5 5 5 5 14 8 5 5 5 5 5 5 15 7 5 5 5 5 5 5 16 7 5 5 5 5 5 5 Table 1(b)

Coated film surface state *) Internal After After After After After After shrinking second second third third Sample submerging exposing stress submerging exposing submerging exposing (kg/cm2) After After After After After After 3 months 4 months 7 months 8 months 11 months 12 months Example 17 6 5 5 5 5 5 5 18 4 5 5 5 5 5 5 19 4 5 5 5 5 5 5 20 5 5 5 5 5 5 5 21 4 5 5 5 5 5 5 22 5 5 5 5 5 5 5 23 6 5 5 5 5 5 5 24 6 5 5 5 5 5 5 Comparative Example 1 38 4 2 2 1 1 1 2 38 3 2 2 1 1 1 3 40 3 1 1 1 1 1 Note: *) Marks in the table have the following means 5 : no crack 4 : cracks of a breadth of less than 0.1 mm 3 : cracks of a breadth of 0.1-0.5 mm 2 : cracks of a breadth of 0.5-1 mm 1 : cracks of a breadth of larger than 1 mm Table 2 Maximum Maximum height Standard height Standard R max length R ma, length Sample (tim) (mm) Sample (item) (mm) Example 1 8 2.5 Example 1 5 9 2.5 2 12 2.5 16 9 2.5 3 10 2.5 17 18 2.5 4 10 2.5 18 10 2.5 5 12 2.5 19 7 2.5 6 10 2.5 20 15 2.5 7 9 2.5 21 13 2.5 8 9 2.5 22 20 2.5 9 9 2.5 23 18 2.5 10 13 2.5 24 9 2.5 11 12 2.5 Comparative 12 10 2.5 Example 1 100 < 8 13 8 2.5 2 100 < 8 14 29 8 3 100 < 8 Note: The above numerical values are arithmetic mean values of Rm,a obtained from the cross-sectional curve determined from 20 portions randomly picked-up from each test plate surface.

Claims

1. Antifouling paint compositions comprising copolymers consisting of an organic tin-containing repeating unit (a) shown by the general formula

wherein R is an alkyl, cycloalkyl or phenyl group having 1-8 carbon atoms and X and Y are hydrogen atom or methyl group, and at least one monomer repeating unit (b) selected from the group consisting of acrylic compounds, vinyl compounds having functional group and vinyl hydrocarbons as a vehicle, cuprous oxide as an antifouling agent and insoluble or difficultly soluble platy, prismatic or needle-like inorganic or organic compounds or a combination of these compounds, which decreases the internal stress in the coated film which is necessarily generated after formation of the coated film to prevent generation of the coated film defect, such as cracks, a weight ratio of the vehicle to cuprous oxide being 1:1-1::5 and the above described compound or the combination thereof being contained in an amount of 1-30% by weight.

2. Antifouling paint compositions as claimed in claim 1, wherein the platy, prismatic or needle-like inorganic compounds are inorganic pigments.

3. Antifouling paint compositions as claimed in claim 2, wherein the platy, prismatic or needle-like pigment is mica, micaceous iron oxide, china clay, gypsum, asbestos, copper powder or tin flake.

4. Antifouling paint compositions as claimed in claim 1, wherein the platy, prismatic or needle-like organic compounds are bactericides, insecticides or herbicides.

5. Antifouling paint compositions as claimed in claim 4, wherein the platy, prismatic or needle-like bactericides are organic tin compounds.

6. Antifouling paint compositions as claimed in claim 5, wherein the platy, prismatic or needle-like organic tin compounds are triphenyltin compounds.

7. Antifouling paint compositions as claimed in claim 6, wherein the platy, prismatic or needle-like triphenyltin compounds are triphenyltin hydroxide, triphentyltin chloride, triphenyltin fluoride, triphenyltin acetate or bis(triphenyltin) cu,a"-dibromosucci- nate.