| 摘要 |
PURPOSE: A manufacturing method of nontoxic color steel sheet is provided to improve electrical conductivity and thermal resistance by assembling chromium-free primer layer and chromium-free top layer in chromium-free coating primer. CONSTITUTION: A manufacturing method of nontoxic color steel sheet comprises: a step of coating chromium-free coating primer in both sides of a metal ring plate, a step of forming chromium-free pretreatment layers(110,120) by heating the coated chromium-free coating primer, a step of forming a chromium-free primer layer(130), and a step of forming chromium-free top layer(140) in the top of the chromium-free primer layer. The chromium-free coating primer includes 1-5 parts by weight of waterborne denatured polyurethane, 10-20 parts by weight of nano silica sol, below 1 parts by weight of nitrogen-contained compound, 0.5-3 parts by weight of cross linking agent, 0.01-0.1 parts by weight of surface tension regulator, and 0.01-0.1 parts by weight of antifoaming agent. The chromium-free primer layer comprises includes 50-60 wt% of polyester in the top of the chromium-free pretreatment layer, 5-10 wt% of melamine hardened resin, 10-20 wt% of one or more among TiO2, SiO2, P2O5, Al2O3, and CaO, 15-20 wt% of solvent which includes one or more between hydrocarbon and cyclohexane, and 10-20 wt% of additives which includes one or more among acrylic, urethane, and epoxy. [Reference numerals] (100) Metal substrate; (110,120) Pretreatment layer; (130) Primer layer; (140) Top layer; (150) Rear coating layer |
