Fluoropolymer coating compositions containing adhesive polymers and substrate coating process
View Patent ↗A liquid fluoropolymer coating composition and a process for using the composition to make fluoropolymer coated polymeric substrates. The liquid fluoropolymer composition comprises fluoropolymer selected from homopolymers and copolymers of vinyl fluoride and homopolymers and copolymers of vinylidene fluoride polymer, solvent, and compatible adhesive polymer comprising functional groups selected from carboxylic acid, sulfonic acid, aziridine, amine, isocyanate, melamine, epoxy, hydroxy, anhydride and mixtures thereof. In the process, the composition is applied to a polymeric substrate comprising functional groups on its surface that interact with said compatible adhesive polymer to promote bonding of said fluoropolymer coating to said substrate. The solvent is removed from the coating composition applied to the substrate to form a fluoropolymer coating on the substrate.
1. A process for making a fluoropolymer coated polymeric substrate comprising:
applying a liquid fluoropolymer coating composition to a polymeric substrate, said fluoropolymer coating composition comprising fluoropolymer selected from polyvinyl fluoride homopolymers and copolymers of vinyl fluoride; solvent; and compatible adhesive polymer comprising functional groups selected from carboxylic acid, sulfonic acid, aziridine, amine, isocyanate, melamine, epoxy, hydroxy, anhydride and mixtures thereof;
said polymeric substrate comprising thermoplastic polyester and a primer layer on its surface, said primer layer providing functional groups that interact with said compatible adhesive polymer to promote bonding of said fluoropolymer coating to said substrate; and
removing the solvent from said coating composition applied to said substrate to form a fluoropolymer coating on said substrate.
2. The process of claim 1 wherein said polymeric substrate is film.
3. The process of claim 1 wherein said compatible adhesive polymer is functional acrylic polymer.
4. The process of claim 1 wherein said fluoropolymer is selected from polyvinyl fluoride homopolymers and copolymers of vinyl fluoride comprising at least 60 mole % vinyl fluoride.
5. The process of claim 1 wherein said coating composition comprises about 1 to about 40 weight % of said compatible adhesive polymer based on fluoropolymer solids content.
6. The process of claim 1 wherein said coating composition further comprises pigment.
7. The process of claim 1 wherein said fluoropolymer of said coating composition is in the form of dispersion particles in said solvent and said solvent is selected from is selected from dimethylacetamide, propylene carbonate, γ-butyrolactone, N-methylpyrrolidone and dimethylsulfoxide.
8. The process of claim 1 wherein said removing of said solvent is performed by heating.
9. The process of claim 2 wherein said fluoropolymer coating composition is applied to both surfaces of said substrate film.
10. The process of claim 1 wherein said thermoplastic polyester of said substrate is selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, and a coextrudate of polyethylene terephthalate/polyethylene naphthalate.
11. The process of claim 1 , wherein said primer comprises an ethylene copolymer.