Release coating
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.
1. A method of applying a release coating onto a pressure sensitive adhesive product comprising:
mixing 10-40% water dispersible or emulsifiable silicone with 60-90% polyethylene terephthalate modified by the addition of a carboxyl functional fatty acid, trimellitic acid, trimellitic anhydride, maleic acid, fumaric acid, isophthalic acid, or any combinations thereof, in the presence of a catalyst, thereby producing a release coating; and
applying the release coating to a support.
2. The method according to claim 1 wherein 65-90% modified polyethylene terephthalate and 10-35% water dispersible or emulsifiable silicone are mixed.
3. The method according to claim 1 wherein the 60-90% polyethylene terephthalate is modified by the addition of trimellitic acid, trimellitic anhydride, maleic acid, fumaric acid or isophthalic acid.
4. The method according to claim 1 wherein the water dispersible or emulsifiable silicone comprises an aqueous emulsion of polyorganosiloxanes and an aqueous emulsion catalyst.
5. The method according to claim 4 wherein the aqueous emulsion catalyst is a platinum catalyst.
6. The method according to claim 4 wherein the aqueous emulsion comprises propylene glycol.
7. The method according to claim 4 wherein the aqueous emulsion catalyst comprises an emulsifying agent, propylene glycol and a platinum complex.
8. The method according to claim 1 wherein the support is a paper substrate.
9. The method according to claim 8 wherein the paper substrate is heated until the coated surface of the paper substrate achieves a temperature of about 100° C.
10. The method according to claim 1 wherein the 60-90% polyethylene terephthalate is modified by the addition of a carboxyl functional fatty acid.
11. The method according to claim 1 wherein the maleic acid is produced from maleic anhydride.