Chromium-free coating composition and surface-treated steel sheet excellent in blackening resistance and corrosion resistance

摘要

The present invention comprises 20 to 70% by weight of a silane-modified water-dispersed polyurethane, 0.5 to 5% by weight of a curing agent, 0.5 to 5% by weight of an anti-blackening agent, 0.5 to 5% by weight of a rust inhibitor, and a lubricant. Provided is a chromium-free coating composition excellent in blackening resistance and corrosion resistance containing 0.5 to 5% by weight and the balance solvent, and the chromium-free coating composition is a steel plate on which a coating layer containing the composition is formed. It has the effect of improving blackening resistance, corrosion resistance, alkali resistance, solvent resistance and fingerprint resistance.