Antifouling coating

Abstract

An antifouling coating which comprises a varnish comprised of a metal-containing acrylic resin having, in a side chain thereof, at least one group represented by the following formula (1): wherein X represents a group of the formula: n represents 0 or 1; Y represents a hydrocarbon group; M represents a metal; m represents an integer equal to [(the valence number of metal M)−1]; A represents an organic acid residue derived from a monobasic acid, said varnish having a nonvolatile fraction of not less than 40 weight % and a viscosity at 25° C. of not more than 18 poises and said antifouling coating having a volatile organic compound (VOC) content of not more than 400 g/L.

1 . An antifouling coating 
 which comprises a varnish comprised of a metal-containing acrylic resin having, in a side chain thereof, at least one group represented by the following formula (1):                          wherein x represents a group of the formula:                          n represents 0 or 1; Y represents a hydrocarbon group; M represents a metal; m represents an integer equal to [(the valence number of metal M)−1]; A represents an organic acid residue derived from a monobasic acid,    said varnish having a nonvolatile fraction of not less than 40 weight % and a viscosity at 25° C. of not more than 18 poises    and said antifouling coating having a volatile organic compound (VOC) content of not more than 400 g/L.    
     
     
         2 . The antifouling coating according to  claim 1   wherein the metal-containing acrylic resin has an average degree of polymerization in the range of 20 to 60.    
     
     
         3 . The antifouling coating according to  claim 1  or  2  
 wherein the acrylic resin constituting said metal-containing acrylic resin has an acid value of 80 to 300 mg KOH/g and a glass transition temperature of not higher than 5° C.  
 
     
     
         4 . The antifouling coating according to  claim 1 ,  2  or  3  
 wherein the monobasic acid has an acid value of less than 200 mg KOH/g.  
 
     
     
         5 . An antifouling coating 
 which comprises a metal-containing acrylic resin having, in a side chain thereof, at least one group represented by the following formula (1):                          wherein X represents a group of the formula:                          n represents 0 or 1; Y represents a hydrocarbon group; M represents a metal; m represents an integer equal to [(the valence number of metal M)−1]; A represents an organic acid residue derived from a monobasic acid,    with 5 to 100 mole % of said organic acid residue derived from a monobasic acid being the residue of a cyclic organic acid.    
     
     
         6 . The antifouling coating according to  claim 5   wherein the cyclic organic acid has an acid value of 120 to 190 mg KOH/g.    
     
     
         7 . The antifouling coating according to  claim 1 ,  2 ,  3 ,  4 ,  5  or  6  
 wherein the monobasic acid has a diterpenoid hydrocarbon skeleton or a salt thereof.  
 
     
     
         8 . The antifouling coating according to  claim 1 ,  2 ,  3 ,  4 ,  5 ,  6  or  7  
 wherein the monobasic acid is selected from the group consisting of abietic acid, hydrogenated abietic acid and their salts.  
 
     
     
         9 . The antifouling coating according to  claim 1 ,  2 ,  3 ,  4 ,  5  or  6  
 wherein the monobasic acid is selected from the group consisting of rosins, hydrogenated rosins and disproportionated rosins.  
 
     
     
         10 . The antifouling coating according to  claim 1 ,  2 ,  3 ,  4 ,  5 ,  6 ,  7  or  8  
 wherein the metal M is copper or zinc.  
 
     
     
         11 . The antifouling coating according to  claim 1 ,  2 ,  3 ,  4 ,  5 ,  6 ,  7 ,  8 ,  9  or  10  
 wherein the ratio of the monobasic acid to the acrylic resin constituting the metal-containing acrylic resin is 0.9/1.1 to 1.2/0.8 by weight on a nonvolatile matter basis.  
 
     
     
         12 . The antifouling coating according to  claim 1 ,  2 ,  3 ,  4 ,  5 ,  6 ,  7 ,  8 ,  9 ,  10  or  11  
 comprising an additional binder resin in a weight ratio, on a nonvolatile basis, of [metal-containing acrylic resin]/[additional binder resin]=100/0 to 30/70.