Pohang Iron & Steel Co. Ltd.

Sang-Geol Noh

Sam-Kyu Chang

Soo-Hyoun Cho

Jae-Ryung Lee

The present invention relates to a resin-coated steel sheet for fuel tanks of an automobile and a resin solution used for the same. The resin solution of the present invention comprises (a) a main solution of water soluble phenoxy resin having a number average molecular weight of 25,000 to 50,000; (b) 2 to 15 phr of melamine resin on the basis of the main solution; (c) 10 to 20 phr of colloidal silica on the basis of the main solution, (d) 2 to 10 phr of teflon resin on the basis of the main solution, and (e) 5 to 70 phr of metallic powder being selected at least one material from the group consisting of Al, Zn, Mn, Co, Ni, Sn and SnO. The resin solution is coated on a cold rolled steel sheet plated with zinc or zinc alloy over which a chromate layer films, and then baked at a local temperature of 160 to 250&deg; C. to prepare a resin-coated steel sheet for fuel tanks of an automobile.

Resin-coated steel for fuel tanks of automobile and method for manufacturing the same

The present invention relates to a surface-treated steel sheet coated with a chromate layer having excellent corrosion resistance, fuel resistance and seam weldability, and a chromate solution used for preparing the surface-treated steel sheet. Specifically, the chromate solution of the present invention comprises (a) a main solution prepared by adding to a chrome solution having 0.4 to 0.8 of trivalent chrome composition and 7 to 50 g/l of dissolved chrome, on the basis of the chrome in the chrome solution, 50 to 80 w % of phosphate, 20 to 40 w % of fluoric acid, 300 to 2000 w % of colloidal silica, 5 to 15 w % of sulfuric acid, and 25 to 40 w % of sodium phosphate, and (b) a hardener solution containing added epoxy silane or glycidyl silane of 2 to 10 w % on the basis of total hardener solution, the pH of which is controlled between 2 and 3, wherein 10 to 60 w % of the hardener solution being added to the main solution.

Growing community of inventors

Pohang, South Korea

Sang-Geol Noh