Corrosion resistant, coated metal laminate, its preparation and coating materials

A coating composition suitable for precoating a metal comprising, as solid,

• (A) 10 to 35% by weight of at least one binder resin whose aromatic ring content in its molecule is less than 50% by weight and which is selected from the group consisting of epoxy resin, alkyd resin, acryl resin, melamine resin, urethane resin, phenol resin, vinyl resin, polyvinyl butyral resin, polyvinyl acetate resin, chlorinated rubber, oil-free polyester resin, phthalic acid resin, styrene resin and polyolefin resin,
• (B) 4 to 30% by weight of polyethylene wax capable of being decomposed exothermically at 300.degree. to 500.degree. C.,
• (C) 15 to 85% by weight of electrically conductive pigment which is essentially of di-iron phosphide and has a mean diameter of less than 20 microns,
• (D) 1 to 71% by weight of iron phosphide decomposition inhibitor whose aqueous suspension has a pH of 6 to 13 and which is selected from the group consisting of alkaline earth metal petroleum sulfonates, zinc chromate, zinc potassium chromate, lead chromate, basic lead chromate, calcium chromate, strontium chromate, zinc phosphate, iron phosphate, aluminum tripolyphosphate, lead silicate, talc, calcium carbonate, silica and zinc powder wherein the amount of zinc powder is less than the iron phosphide amount, and
• (E) 0 to 70% by weight of other inorganic pigment selected from the group consisting of zinc chromate, lead chromate, calcium chromate, strontium chromate, zinc phosphate, iron phosphate, aluminium tripolyphosphate, lead silicate, silica, calcium carbonate, talc, alumina, chromium oxide, iron oxide and lead oxide, provided that the total amount of (C), (D) and (E) is 35 to 86% by weight of the total solids of the composition.