Roller coating to make post-formable non-stick smooth substrates

A process of coating to produce a coated substrate wherein the coating comprises a two-layer coating system including a primer applied to the substrate and a topcoat applied to the primer, said primer being the cured product of an aqueous coating composition comprising perfluorocarbon resin and a binder consisting essentially of polyamide imide and polyphenylene sulfide resin, wherein said perfluorocarbon resin comprises two different perfluorocarbon resins, the first being a polymer of polytetrafluoroethylene having a melt viscosity of at least 10.sup.10 Pa Sec the second being a copolymer of tetrafluoroethylene and hexafluoropropylene having, a melt viscosity in the range of 10.sup.2 to 10.sup.7 Pa Sec, the weight proportions being in the range of 50 to 85% of the first such resin and 15-50% of the second such resin based on the total of said first and second resins the ratio of the polyamide imide to polyphenylene sulfide being in the range of 3:1 to 1:3, and wherein the weight ratio in the cured coating of fluoropolymer to binder is in the range of 2:1 to 1:1, and said topcoat comprising polytetrafluoroethylene and mica, said topcoat having been cured from a coating composition which also included a polymer which decomposed and left essentially no residue on curing of the coating, said process comprising:

• applying the coating layers by roller coating to the substrate in the form of a disc, which has an average surface roughness profile less than 1.3 microns RMS measured from a centerline, without completely drying one coating before applying the next, and then curing the coating system by heating to a temperature of at least 400.degree. C., and then forming the disc by deep drawing with a draw ratio of depth to diameter of at least about 0.2:1.