Coating compositions for producing transparent super-hydrophobic surfaces

Abstract

A coating composition and process for generating transparent, near-transparent, and semi-transparent super-hydrophobic coatings on surfaces having a contact angle of greater than 165 degrees. The composition comprises hydrophobic nanoparticles of silsesquioxanes containing adhesion promoter groups and low surface energy groups.

1 . A transparent hydrophobic coating composition comprising:
 a) at least one R 1  group containing a component comprising an alkyl, aryl groups bonded directly to an Si atom of the silsesquioxanes structure, said alkyl groups are preferably with carbon atom C 1  to C 20 ;   R 2  groups containing a component comprising a substituted alkyl group; and   a substituted group comprising an adhesion promoter; and   a substitute group comprising a cross linking group;   b) a solvent: and   c) an adhesive promoter.   
     
     
         2 . The transparent hydrophobic coating composition of  claim 1 , said alkyl groups including an additional moiety bonded there to selected from the group consisting of a hydroxyl group, a CF 3 , and a perfluoro group. 
     
     
         3 . The transparent hydrophobic coating composition of  claim 1 , wherein said aryl group substitutes phenyl and benzyl groups. 
     
     
         4 . The transparent hydrophobic coating composition of  claim 1 , wherein said cross linking group is selected from the group consisting of a hydroxyl, an amino, and an epoxy group. 
     
     
         5 . The transparent hydrophobic coating composition of  claim 1 , wherein said polysiloxane comprises a polysilsesquioxane having repeating units of the formula. 
     
     
         6 . A hydrophobic self-cleaning coating composition for forming a dirt repellant film on a clear, translucent, or painted metal, glass, or polymer substrate, comprising an effective amount of nanoparticles of a treated fumed silica in an acetone in solution imparting a degree of hydrophobicity to a coated surface providing a wetting surface having a contact angle of at least 165 degrees as compared to water having a contact angle of from 80 to 90 degrees on a noncoated surface and said composition imparting a degree of hydrophobicity to a coated surface providing a wetting surface having a tilt angle of sliding of less than 2 degrees as compared to water having a tilt angle of sliding of 90 degrees on a noncoated surface;
 said transparent hydrophobic coating composition comprising:   a) at least one R 1  group containing a component comprising an alkyl, aryl groups bonded directly to an Si atom of the silsesquioxanes structure, said alkyl groups are preferably with carbon atom C 1  to C 20 ;   R 2  groups containing a component comprising a substituted alkyl group; and   a substituted group comprising an adhesion promoter; and   a substitute group comprising a cross linking group;   b) a solvent: and   c) An adhesive promoter.   
     
     
         7 . The composition of  claim 1 , wherein said composition is clear upon application to a treated surface. 
     
     
         8 . The composition of  claim 1 , wherein said composition is translucent upon application to a treated surface. 
     
     
         9 . The composition of  claim 1 , including an aerosol. 
     
     
         10 . The composition of  claim 9 , wherein said composition is dispersed in an aerosol propellant containing a solvent selected from the group consisting of an alcohol, a hydrocarbon, mineral spirits, and water. 
     
     
         11 . The composition of  claim 10 , wherein said aerosol propellant is selected from the group consisting of a carbon dioxide, a hydrocarbon, a fluorocarbon, and compressed air. 
     
     
         12 . The composition of  claim 11  wherein said hydrocarbon, comprises a propane/isobutane. 
     
     
         13 . The composition of  claim 1 , including a binding agent applied to said substrate, prior to application of said hydrophobic self-cleaning coating composition. 
     
     
         14 . The composition of  claim 13 , wherein said binding agent comprises a binding agent pretreatment solution containing a zinc oxide. 
     
     
         15 . The composition of  claim 14 , wherein said binding agent comprises about 0.05% by weight of said binding agent pretreatment solution. 
     
     
         16 . The composition of  claim 1 , wherein said nanoparticles are from about 7 to about 600 nanometers.