PURPOSE: To obtain a lubricating resin-treated steel sheet excellent in press forming property and corrosion resistance by providing a chromate film having a specified coating built-up on the both surfaces of a zinc based plated steel sheet and providing the resin layer having a specified composition and mechanical characteristic in a specified coating built-up.
CONSTITUTION: The chromate film is applied on the both surface of the zinc or zinc based plated steel sheet. The coating built-up of the film is 10-20mg/m2 per one surface expressed in terms of metallic chromium. Moreover, a resin mixture or a resin composition is applied on the chromate film in the coating built-up of 0.3-3.0g/m2 in dry base. And, the resin mixture or the resin composite material is the composition of 100 pts.wt. resin having hydroxy and/or carboxyl group, 10-80 pts.wt. silica and 1-20 pts.wt. polyolefine wax, and has the film mechanical characteristics of ≥100% elongation in an uniaxial tensile test and ≤50N/mm2 breaking strength. In such a case, the polyolefine wax has ≥70°C m.p. and 1-7μm average grain size preferably.
OGATA HIROYUKI
OKUNO KEIZOU
NARUSE YOSHIHIRO
