Marine antifoulant coating

Abstract

A protective coating applied to the underwater portion of a marine vessel operable to inhibit the growth of marine foulants. The coating comprises a polymer, a marine biocide, a preservative, and optionally an antimicrobial agent. In certain embodiments, the marine biocide, preservative, and optional antimicrobial agent are chemically bonded with the polymer thereby significantly reducing the ability of the biocide, preservative, and antimicrobial agent to leach from the coating into the surrounding environment.

1 . A marine antifoulant coating for application to a surface of a marine vessel said coating comprising:
 a polymer;   a marine biocide; and   a preservative that is chemically bonded with said polymer.   
     
     
         2 . The coating of  claim 1 , wherein said marine biocide comprises copper. 
     
     
         3 . The coating of  claim 2 , wherein said coating has an average copper release rate of less than about 0.3 micrograms per square centimeter per day after 90 days as determined by ASTM D 6442-05. 
     
     
         4 . The coating of  claim 1 , wherein said polymer presents a particle size from about 20 microns to about 80 microns. 
     
     
         5 . The coating of  claim 1 , wherein said marine biocide presents a particle size from about 40 microns to about 60 microns. 
     
     
         6 . The coating of  claim 1 , wherein said preservative presents a particle size from about 20 microns to about 80 microns. 
     
     
         7 . The coating of  claim 1 , wherein said marine biocide and preservative are dispersed within said polymer. 
     
     
         8 . The coating of  claim 1 , wherein said polymer is chemically bonded with said marine biocide. 
     
     
         9 . The coating of  claim 1 , wherein said coating further comprises between about 2% to about 8% by weight of an antimicrobial agent. 
     
     
         10 . The coating of  claim 1 , wherein said coating further comprises between about 10% to about 20% by weight of at least one synthetic resin selected from the group consisting of fluoropolymers and silicone powder. 
     
     
         11 . The coating of  claim 10 , wherein said fluoropolymer is selected from the group consisting of polytetrafluoroethylene, perfluoroalkoxy polymer resin, polyethylenetetrafluoroethylene, and polyvinylidene fluoride. 
     
     
         12 . A method of forming a marine antifoulant coating, the method comprising the steps of:
 a) forming a mixture comprising particles of a polymer, a marine biocide, and a preservative;   b) heating said mixture to a temperature above the glass transition temperature of said polymer thereby forming a flowable, mixture comprising said polymer having particles of said biocide and preservative dispersed therein; and   c) applying a variable electric field to said heated mixture to alter the orientation of said polymer and said particles of biocide and preservative relative to each other.   
     
     
         13 . The method of  claim 12 , wherein said mixture comprises between about 40% to about 70% by weight of said polymer. 
     
     
         14 . The method of  claim 12 , wherein said mixture comprises between about 37% to about 52% by weight of said marine biocide. 
     
     
         15 . The method of  claim 12 , wherein said mixture comprises between about 2% to about 12% by weight of said preservative. 
     
     
         16 . The method of  claim 12 , wherein said polymer, prior to being heated, presents a particle size of between about 20 microns to about 80 microns. 
     
     
         17 . The method of  claim 12 , wherein said marine biocide presents a particle size of between about 40 microns to about 60 microns. 
     
     
         18 . The method of  claim 12 , wherein said preservative presents a particle size of between about 20 microns to about 80 microns. 
     
     
         19 . A method of applying a marine antifoulant coating to a surface of a marine vessel, said method comprising the steps of:
 a) injecting a heated blended mixture comprising a polymer, a marine biocide, and a preservative into a plasma stream;   b) enshrouding said plasma stream and heated blended mixture with a shielding gas to prevent contamination of said heated blended mixture; and   c) directing said plasma stream and said heated blended mixture onto said marine vessel surface, whereby said heated blended mixture becomes adhered to said surface.   
     
     
         20 . The method of  claim 19 , wherein said heated blended mixture comprises between about 40% to about 70% by weight of said polymer, between about 37% to about 52% by weight of said marine biocide, and between about 2% to about 12% by weight of said preservative.