Pohang Iron & Steel Co. Ltd.

Sam-Kyu Chang

Soo-Hyoun Cho

Jae-Ryung Lee

Sang-Geol Noh

Young-Jong Yoo

Seok-Joo Lee

Sang-Geol No

Youn-Kyun Song

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

A coating composition for forming insulating films, a non-oriented electrical steel sheet with the coating composition coated thereon, and a method for forming the insulating films on the steel sheet, are disclosed. The coating composition includes the following ingredients for each 100 g of phosphoric acid of a primary aluminum phosphate solution. The coating composition comprises 28-98 g (solid weight) of an acid-soluble emulsion type acrylic-styrenic copolymer resin, 6-18 g of zinc nitrate, 4-13 g of a silicon additive, 18-35 g of ethylene glycol, and 3-11 g of non-ionic surfactant. The non-oriented electrical steel sheet is coated with the above coating composition. The coating composition is superior in roll coating workability and in film characteristics, and further, it is environmentally friendly and has superior aesthetics.

Coating composition for forming insulating films, non-oriented electrical steel sheet with the coating composition coated thereon, and method for forming the insulating films on the steel sheet

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.

Surface-treated steel sheet coated with chromate film for fuel tanks and method of fabricating the same

A surface-treated sheet for fuel tanks includes a cold-rolled steel sheet with a low carbon content, a zinc or zinc-based alloy plating layer formed on the steel sheet, and a chromate film coated on the zinc or zinc-based alloy plating layer. The chromate film is formed from a chromate solution. The chromate solution includes a subject solution and an aqueous silane solution in an amount ranging from 5 to 50% by weight of the subject solution. The subject solution contains a chrome aqueous solution where the concentration of chrome is in the range of 5-50 g/l and the ratio of trivalent chrome to the chrome content is in the range of 0.4 to 0.8. Phosphoric acid in an amount ranging from 20 to 150% by weight with respect to the chrome content, fluoric acid in an amount ranging from 10 to 100% by weight with respect to the chrome content, colloidal silica having pH of 2-5 in an amount ranging from 50 to 2000% by weight with respect to the chrome content, and sulfuric acid in an amount ranging from 5 to 30% by weight with respect to the chrome content are mixed with the chrome aqueous solution. The aqueous silane solution contains 2-10 wt % of Epoxy-based silane and has a pH of 2-3. A resin coating layer is formed on one side or both sides of the chromate film. The resin coating layer is formed from a resin solution. The resin solution includes a phenoxy resin solution having a molecular weight of 25,000-50,000, colloidal silica of 10-20 phr with respect to the phenoxy resin content, and melamine resin of 2-15 phr with respect to the phenoxy resin content.

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Pohang, South Korea

Sam-Kyu Chang