PURPOSE: To produce a colored org. composite steel sheet excellent in chromium elution resistance by applying a chromate film and an org. film of org.-solvent paint composition on the surface of a galvanized steel sheet under specified conditions.
CONSTITUTION: A chromate film 3 having 10-150mg/m2 thickness is formed on one or both sides of a steel sheet 1 having a zinc plating film 2. Further, an org. film 4 having 0.05-2μm thickness and consisting of the org.-solvent paint composition contg. 30-90%, as the nonvolatile matter wt.%, urethane epoxy polyester resin (having 300-100,000 number average mol.wt.), 0.5-5% complexing agent (polyoxyethylene glycol), 5-40% silica powder (having 1-100μm average grain diameter), 0.1-10% polyethylene wax (having 1,000-10,000mol.wt.) and 0.5-5% of at least one kind among insoluble azo, azo-lake and phthalocyanine org. pigments or inorg. pigments such as red iron oxide having 0.05-2μm average grain diameter is formed on the chromate film 3.
SHINDO YOSHIO
AZAMI TADAO
TANIMURA KOJI
