PROCESS FOR COATING A GLASS SUBSTRATE WITH AN AQUEOUS FLUOROPOLYMER COATING

摘要

The invention relates to an process for coating a glass substrate with an environmentally friendly aqueous, fluoropolymer coating composition. The process involves applying a polyurethane primer to the glass substrate, and partially, but not completely crosslinking this primer coating. An aqueous hydroxyl-functional fluoropolymer coating is then applied to the partially crosslinked primer coating, and the coating allowed to fully cure. The invention also relates to the intertwined multilayer primer/fluoropolymer coating on the glass substrate. The final coating has excellent wet adhesion to glass, good weathering, durability, chalking resistance, chemical resistance, and dirt pickup resistance.

主权项

1. A process for forming a fluoropolymer coating on a substrate comprising the steps of:
a) coating said substrate on at least one side or at least one edge with a primer composition comprising:
1) at least one hydroxy-functional polyurethane,2) at least one polyisocyanate,3) at least one organosilane coupling agent,4) optionally an antioxidant5) optionally one or more additives selected from the group consisting of coalescent agents, pigments, dyes, wetting agents, UV absorbers, and heat stabilizers; b) curing said primer composition to leave 15-90% of unreacted isocyanate or hydroxyl functional groups; c) coating said primered substrate with an aqueous hydroxy-functional fluoropolymer composition comprising:
1) a hydroxy-functional fluoropolymer,2) a hydrophilic aliphatic polyisocyanate,3) optionally one or more additives selected from the group consisting of pigments, coalescent agents, wetting agents, UV absorbers, and heat stabilizers; and d) curing said coated substrate.