De-polluting and self-cleaning epoxy siloxane coating

Abstract

De-polluting, self-cleaning coating compositions are disclosed which comprise photocatalytic titanium dioxide and a binder comprising an epoxy siloxane polymer. The compositions produce durable, self-cleaning coatings with photocatalytic activity against pollutants in the air, such as NO x compounds.

1 . A composition for forming a self-cleaning, de-polluting coating comprising:
 (i) photocatalytic titanium dioxide;   (iii) a binder comprising an epoxy-functional silicon compound and an amino-functional compound;   (iv) one or more pigments; and   (v) an alkaline extender that is capable of neutralizing acidic species produced from degradation of NO x  compounds;   wherein the total pigment volume concentration of the composition is about 5% to about 70% by volume of the dry coating.   
   
   
       2 . The composition of  claim 1 , wherein the amino-functional compound is an amino-functional silicon compound. 
   
   
       3 . The composition of  claim 2 , wherein the amino-functional silicon compound is an amino silane. 
   
   
       4 . The composition of  claim 1 , wherein the epoxy-functional silicon compound is an epoxy siloxane polymer. 
   
   
       5 . The composition of  claim 1 , wherein the epoxy-functional silicon compound is an epoxy silane. 
   
   
       6 . The composition of  claim 1 , wherein the epoxy-functional silicon compound comprises one or more terminal epoxy groups. 
   
   
       7 . The composition of  claim 1 , further comprising a polysiloxane polymer or a silane compound. 
   
   
       8 . The composition of  claim 1 , wherein the pigment is titanium dioxide. 
   
   
       9 . The composition of  claim 1 , wherein the photocatalytic titanium dioxide is greater than about 95% in the anatase crystalline form. 
   
   
       10 . The composition of  claim 1 , wherein the total pigment volume concentration is about 10% to about 50%. 
   
   
       11 . The composition of  claim 1 , wherein the total pigment volume concentration is about 10% to about 40%. 
   
   
       12 . The composition of  claim 1 , wherein the total pigment volume concentration is about 15% to about 35%. 
   
   
       13 . The composition of  claim 1 , wherein the total pigment volume concentration is about 15% to about 30%. 
   
   
       14 . The composition of  claim 1 , wherein the total pigment volume concentration is about 20% to about 35%. 
   
   
       15 . The composition of  claim 1 , wherein the total pigment volume concentration is about 20% to about 30%. 
   
   
       16 . The composition of  claim 1 , wherein the composition comprises about 1% to about 10% photocatalytic titanium dioxide. 
   
   
       17 . The composition of  claim 1 , wherein the composition comprises about 1% to about 5% photocatalytic titanium dioxide. 
   
   
       18 . The composition of  claim 1 , wherein the composition comprises about 1% to about 3% photocatalytic titanium dioxide. 
   
   
       19 . The composition of  claim 1 , wherein the composition comprises about 1% to about 5% photocatalytic titanium dioxide and wherein the total pigment volume of the composition is about 10% to about 40%. 
   
   
       20 . The composition of  claim 1 , wherein the composition comprises about 1% to about 5% photocatalytic titanium dioxide and wherein the total pigment volume of the composition is about 20% to about 35%. 
   
   
       21 . The composition of  claim 1 , wherein the extender is calcium carbonate.