ENVIRONMENTALLY FRIENDLY SURFACE TREATING AGENT FOR GALVANIZED STEEL SHEET, GALVANIZED STEEL SHEET, AND MANUFACTURING METHOD FOR GALVANIZED STEEL SHEET

摘要

An environmentally friendly surface treating agent for a galvanized steel sheet. An aqueous solution thereof comprises the following solid components in parts by mass: 30 to 55 parts of modified closed cationic polyurethane resin A; 32 to 60 parts of a silane coupling agent B, wherein the silane coupling agent B comprises: an organic silane coupling agent B1 comprising at least one activated hydrogen amide group functional group and an organic silane coupling agent B2 comprising at least one epoxy group functional group, B1/B2 being 0.4 to 1; 3 to 15 parts of surface grafting high density polyethylene particles or surface grafting polyamide particles C; 0.01 to 0.5 part of a vanadium-containing compound D calculated in terms of an element vanadium; 0.5 to 1.5 parts of a phosphor-containing compound E calculated in terms of an element phosphor; 0.1 to 1 part of a fluorine-containing titanium compound F calculated in terms of an element titanium; and 0.01 to 1 part of a cerium-containing compound G calculated in terms of an element cerium.