Fluororesin coating composition for forming a topcoat and coating film therefrom
View Patent ↗Provided is a fluororesin coating composition for forming a topcoat having improved non-tackiness and water and oil repellency. The fluororesin is crystalline tetrafluoroethylene and perfluoro(ethyl vinyl ether) copolymer having a perfluoro(ethyl vinyl ether) content of 8 to 20 mass % based on the total mass of the copolymer.
1. A fluororesin coating composition for forming a topcoat, the fluororesin coating composition consisting essentially of a crystalline copolymer consisting of tetrafluoroethylene and perfluoro(ethyl vinyl ether) having a perfluoro(ethyl vinyl ether) content of 8 to 20 mass% based on the total mass of said crystalline copolymer.
2. The coating composition of claim 1 , which is an aqueous coating composition or a powder coating composition.
3. A coating film on a substrate formed from the coating composition of claim 1 .
4. The coating film of claim 3 , wherein said substrate is primer coated or the surface of said substrate is chemically treated prior to being coated with said coating film.
5. The coating film of claim 3 , which is heat treated at the melting point or higher of said crystalline copolymer.
6. The coating film of claim 3 , wherein the contact angle of n-hexane on said coating film at 25° C. and 60% relative humidity is 27 degrees or more.
7. An article, comprising the coating composition according to claim 1 coated on a substrate.
8. A method of forming a coating film on a substrate, comprising the steps of:
coating the coating composition of claim 1 on a substrate; and then performing heat treatment on the coated substrate.
9. The method according to claim 8 , wherein said heat treatment is carried out at the melting point or higher of said crystalline copolymer.
10. The coating composition of claim 1 , wherein the perfluoro(ethyl vinyl ether) content is 8 to 15 mass% based on the total mass of said polymer.
11. The coating composition of claim 10 , wherein the perfluoro(ethyl vinyl ether) content is 9 to 12 mass% based on the total mass of said polymer.
12. The coating composition of claim 1 , wherein the mass of said crystalline copolymer forms at least 80 mass% of a solid content of the fluororesin coating composition.
13. The coating composition of claim 12 , wherein the mass of said crystalline copolymer forms at least 90 mass% of the solid content of the fluororesin coating composition.
14. The coating composition of claim 1 further comprising at least one additive selected from the group consisting of a surfactant, a film-forming agent, a thickening agent, and a combination thereof.
15. The coating composition of claim 14 , wherein the coating composition is an aqueous dispersion further comprising water.
16. The coating composition of claim 1 , wherein the coating composition is a powder coating composition.