PAINT FOR HOT-DIP GALVANIZED STEEL SHEET, METHOD FOR TREATING HOT-DIP GALVANIZED STEEL SHEET, PROCESS FOR PRODUCING SURFACE-TREATED HOT-DIP GALVANIZED STEEL SHEET, AND SURFACE-TREATED HOT-DIP GALVANIZED STEEL SHEET

摘要

The present invention provides a paint for hot-dip galvanized steel sheets which is for use in imparting, to a hot-dip galvanized steel sheet, excellent appearance properties, excellent rubbing resistance, and excellent corrosion resistance. The paint for hot-dip galvanized steel sheets according to the present invention contains a cationic polyurethane resin (A) having at least one kind of cationic functional groups selected from among primary to tertiary amino groups and quaternary ammonium salt groups, wherein the cationic polyurethane resin (A) includes a polycarbonate structural unit and bisphenol structural units, the loss modulus E" of the cationic polyurethane resin (A) shows a maximum peak value at a temperature (Tg1) in the range of -60ºC to -5ºC, and the loss tangent tanδ, which is the ratio of the loss modulus E" to the storage modulus E' of the cationic polyurethane resin (A), has one peak.