Claims
- 1. A process for coating a metal surface with a fluororesin comprising applying to said metal surface a primer composition comprising a solution or a dispersion in an organic solvent, of a polyether sulfone, a fluorinated resin, at least one polymer selected from the group consisting of a polyamideimide, and a polyimide, and a particulate metal, in which the proportion of the polyether sulfone: one or both of polyamideimide and polyimide is from 55:45 to 95:5 and the ratio of the total polyether sulfone and one or both of polyamideimide and polyimide to the fluororesin is 20:80 to 70:30 by weight, and; applying the fluororesin to the resultant primed layer as a powder coating.
- 2. A process of claim 1 wherein the fluororesin comprises at least one member selected from the group consisting of tetrafluoroethylene/hexafluoropropylene copolymer and tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer.
- 3. The process of claim 1 wherein the fluororesin is applied as a powder.
- 4. The process of claim 1 wherein the particulate metal comprises aluminum or an alloy thereof.
- 5. The process of claim 1 wherein the polyamideimide and polyimide are derived from trimellitic anhydride and methylene dianiline.
- 6. The process of claim 1 wherein the primer composition further comprises at least one member selected from the group consisting of a viscosity regulator, stabilizer, colorant and dispersant.
- 7. The process of claim 1 wherein the organic solvent comprises at least one member selected from the group consisting of N-methyl pyrrolidone, N-methylpyrrolidone and diacetone alcohol, and N-methyl pyrrolidone and xylene.
- 8. The process of claim 4 wherein the particulate aluminum comprises about 1-15 wt % based on the solids of the primer composition.
- 9. The process of claim 1 wherein the primer composition is about 5 to 15 microns thick.
- 10. The process of claim 1 further comprising drying the primer composition at a temperature of ambient temperature to about 200.degree. C. prior to applying the fluororesin composition.
- 11. The process of claim 3 wherein the powder is sintered at a temperature of about 350.degree. to 400.degree. C.
- 12. The process of claim 1 wherein the metal surface comprises at least one member selected from the group consisting of aluminum, steel, and stainless steel.
CROSS REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of application Ser. No. 08/182,633 filed Jan. 26, 1994 now abandoned.
US Referenced Citations (23)
Foreign Referenced Citations (4)
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Date |
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0343015 |
Nov 1989 |
EPX |
0389966 |
Oct 1990 |
EPX |
WO9102773 |
Mar 1991 |
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WO9210309 |
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Continuation in Parts (1)
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Number |
Date |
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Parent |
182633 |
Feb 1994 |
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