12th International Conference on Zinc & Zinc Alloy Coated Steel Sheet - GALVATECH 2021

The pre-painted steel sheet is widely used as the panel of audio visual systems and office automation equipments (flat-panel TV, DVD, and so on). 　The pre-painted steel sheet generally has the primer-paint and the top-paint on a chemical conversion galvanized steel sheet. These paints are solvent-based and applied in the coil coating line. The total paint thickness of conventional pre-painted steel is 15 μm or more, and exhibit the excellent appearance, formability, and many performances of the steel sheet. However, due to intensifying competition and lower prices for home appliances, development of low cost and high productivity pre-painted steel sheet has been desired. 　To meet these demands, we had developed new pre-painted steel sheet coated with one layer solvent type painting that can be manufactured at EGL inline painting. To develop this pre-painted steel, we pursued to make the film thinner than before for the cost reduction. Furthermore, to apply it in the galvanizing line, we also needed to achieve a shorter baking time for the productivity. However, in order to achieve these goals, we have to improve the appearance of paint film, corrosion resistance and solvent resistance and so on. In this paper, we introduce the development contents and performance of the developed pre-painted steel sheet.