Hydrophilic compositions, methods for their production, and substrates coated with such compositions

Abstract

Liquid compositions are disclosed that include a photocatalytic material and a hydrophilic binder that includes an essentially completely hydrolyzed organosilicate. Also disclosed are methods of making such compositions, methods of coating a substrate with a hydrophilic composition, and substrates coated with such compositions. The compositions may, for example, be embodied as stable one-pack compositions.

1 . A method of coating a substrate comprising:
 (a) applying to the substrate a liquid composition comprising (1) a photocatalytic material present in an amount ranging from 0.1 to 0.75 percent by weight based on the total weight of the composition, (2) a hydrophilic essentially completely hydrolyzed organosilicate comprising silanol groups present in the liquid composition in an amount ranging from 0.1 to 2 percent by weight calculated as SiO 2 , based on the total weight of the composition, and (3) water present in an amount sufficient to prevent a condensation reaction of the silanol groups, and   (b) curing the composition applied in step (a).   
     
     
         2 . The method of  claim 1 , wherein the composition is cured by exposing the composition to air for at least two hours at 25° C. 
     
     
         3 . The method of  claim 1 , wherein the substrate comprises cement. 
     
     
         4 . The method of  claim 1 , wherein the substrate comprises glass. 
     
     
         5 . The method of  claim 1 , wherein the pH of the liquid composition is no more than 3.5. 
     
     
         6 . The method of  claim 1 , wherein the dry film thickness of the coating layer is 10 to 100 nanometers.