| 摘要 |
The main purpose of the present invention is to provide a low-cost white precoated steel sheet which has excellent degree of whiteness, adhesion, chemical resistance and corrosion resistance. The present invention is a precoated steel sheet which has a zinc-based plating layer and a chemical conversion coating film on at least one surface of a steel sheet. The chemical conversion coating film does not contain titanium oxide and a chromium compound. The precoated steel sheet additionally comprises only a single layer of a white coating film that is formed on the chemical conversion coating film and contains titanium oxide, a rust preventive pigment, a polyester resin and an epoxy resin. The titanium oxide is contained in the white coating film in an amount of 30-60% by mass, and the rust preventive pigment is composed of a calcium-modified silica. The calcium-modified silica is contained in the white coating film in an amount of 0.5-10% by mass. The epoxy resin is contained in the white coating film in an amount of 0.5-5% by mass, and the white coating film has a film thickness of 8-24 μm. |
