Release coating for aluminum cooking utensil

摘要

Anti-stick coating comprises an undercoat applied directly onto the aluminium and which is coated with a primary layer, which in turn is coated with an outer layer. The primary layer is obtained from an aqueous dispersion of polytetrafluoroethylene (PTFE), polyamide-imide resin and tetrafluoroethylene and poly(propyl vinyl ether) copolymer. The outer layer is obtained from an aqueous dispersion of PTFE. The under coat is obtained from a solution of polyamide-imide resin in organic solvent. Preferably the undercoat is obtained from a mixture of polyamide-imide resin and polyphenylene sulphide. The organic solvent is N-methylpyrrolidone, dimethylformamide or a mixture of N-methylpyrrolidone/xylene or DMF/xylene. The undercoat further comprises inert fillers, such as inorganic pigments, metallic flakes, alumina and quartz. Preferably, the undercoat comprises 30 pts.wt. of polyamide-imide resin (dried), 230 pts.wt. N-methylpyrrolidone, 0-10 pts.wt. xylene, 0-25 pts.wt. pigment (inorganic or carbon black), 0-40 pts.wt. aluminium flakes and 0-80 pts.wt. of polyphenylene sulphide.