Release coating

Abstract

Described herein is the use of a modified PET in combination with a vinyl addition silicone water-based release coating to provide performance equivalent to the silicone by itself at a lower cost than the silicone by itself and resulting in a release backing paper that can be repulped and recycled in conventional recycled paper mills avoiding the additional cost of sending the scrap paper to landfill.

What is claimed is: 
     
         1 . A release coating for a pressure sensitive adhesive product comprising:
 60-90% polyethylene terephthalate modified by the addition of carboxyl functional fatty acids and 10-40% water dispersible or emulsifiable silicone.   
     
     
         2 . The release coating according to  claim 1  comprising 65-90% modified polyethylene terephthalate and 10-35% water dispersible or emulsifiable silicone. 
     
     
         3 . The release coating according to  claim 1  wherein the carboxyl functional fatty acid is selected from the group consisting of trimellitic acid, trimellitic anhydride, maleic acid, maleic anhydride, fumaric acid and isophthalic acid. 
     
     
         4 . The release coating according to  claim 1  wherein the water dispersible or emulsifiable silicone comprises an aqueous emulsion of polyorganosiloxanes and an aqueous emulsion catalyst. 
     
     
         5 . The release coating according to  claim 4  wherein the aqueous emulsion catalyst is a platinum catalyst. 
     
     
         6 . The release coating according to  claim 4  wherein the aqueous emulsion of polyorganosiloxanes includes propylene glycol and polydimethyl (methyl hydrogen) siloxane. 
     
     
         7 . The release coating according to  claim 4  wherein the aqueous emulsion catalyst comprises an emulsifying agent, propylene glycol and a platinum complex.