| 摘要 |
PURPOSE:To satisfy all of various properties (corrosion resistance, press moldability, spot weldability, cation electrodeposition painting properties, low temp. chipping resistance, sharpness after painting) required on the inner and outer surfaces of an exterior steel panel for a car in an org. composite surface treated steel panel wherein a chromate film and an org. resin film are provided on a zinc or zinc alloy (e.g. Zn-Ni, Zn-Fe) plated steel panel. CONSTITUTION:A bright steel panel of which the surface roughness Ra is O.3mum or less on at least a single surface is used as a base material and the uppermost layer on the steel panel is composed of a crosslinked epoxy resin film containing 0.1-20wt.% of a melamine/cyanuric acid adduct and 1-20wt.% of polyolefin wax and having a film thickness of 0 1-2.0mum. Silica is added to a chromate film containing 20-200mg/m<2> of metal Cr in such an amt. that a SiO2/Cr wt. ratio becomes 0.05-4.0 and/or 5-40wt.% of SiO2 is added to the org. resin film. |
