ZINC-BASED METAL PLATED STEEL PLATE OR ALUMINUM-BASED METAL PLATED STEEL PLATE AND ORGANICALLY COVERED STEEL PLATE

摘要

PROBLEM TO BE SOLVED: To provide zinc-based metal plated steel plate or aluminum-based metal plated steel plate covering compositions which exhibit excellent corrosion resistance without a chromate coated film and, at the same time, can provide rust proof steel plates excellent in processability and coating adhesion as well. SOLUTION: It has been found that the above described purpose can be attained by employing covering compositions comprising a specific corrosion- resistant improver-bound organic resin and an acid which comes to an etching agent, and these covering compositions comprise (A) a film-forming organic resin in which a hydrazine derivative has been bound with an organic resin, preferably (A) a film-forming organic resin of a reaction product of (a) an epoxy group-containing resin and (b) an active hydrogen-containing agent comprising a hydrazine derivative and (B) an acid capable of etching zinc or aluminum.