Posco

Daehan Parkerizing Co., Ltd.

Yeong-Sool Jin

Jin-Tae Kim

Sang-Heon Kim

Noi-Ha Cho

Rho-Bum Park

Sung-Mun Keom

Byung-Kuk Jung

Kook-Jin Han

Sang-Keol Noh

Provided is a chromium-free, low-temperature curable, metal-surface treatment composition comprising 5 to 30 parts by weight of a silane compound having an epoxy group and a silane compound having an amino group or a hydrolytic condensate thereof; 0.1 to 5 parts by weight of a vanadium compound; 0.1 to 5 parts by weight of a magnesium compound; 1 to 10 parts by weight of organic/inorganic acids; 0.05 to 2 parts by weight of a crosslinking accelerating and coupling agent; 0.01 to 1 part by weight of an antifoaming agent; 1 to 2 parts by weight of a wetting agent; and the balance of water and ethanol, based on 100 parts by weight of the total solution. In addition, a steel sheet coated with the above-described metal-surface treatment composition is low-temperature curable and provides anticorrosiveness while containing no chromium components.

Chrome-free composition of low temperature curing for treating a metal surface and a metal sheet using the same

A spangle-free, hot-dip galvanized steel sheet, and a method and device for manufacturing the same. The hot-dip galvanized steel sheet is characterized in that a solidified zinc crystal of hot-dip galvanized layer has an average crystalline texture particle diameter of 10 to 88 &#x3bc;m and there is no solidification traces of dendrites upon observing under a microscope at a magnification of 100&#xd7;. The method comprises dipping a steel sheet in a bath of a zinc-coating solution containing 0.13 to 0.3% by weight of aluminum; air-wiping the steel sheet to remove an excess of the coating solution; spraying water or an aqueous solution on the air-wiped steel sheet, using a steel sheet temperature in the range of a hot-dip galvanization temperature to 419 &#xb0; C. as a spray initiation temperature and using a steel sheet temperature in the range of 417 &#xb0; C. to 415 &#xb0; C. as a spray completion temperature; passing sprayed liquid droplets of water or aqueous solution through a mesh-like high-voltage charged electrode which is electrically charged with a high voltage of &#x2212;1 to &#x2212;50 kV; and allowing the electrode-passed liquid droplets to be bound to the surface of the steel sheet and hereby being served as solidification nuclei of molten zinc.

Method of manufacturing hot-dipped galvanized steel sheet

Disclosed is a paint composition having high far-infrared emissivity, antibiotic activity and solvent resistance and a precoated metal sheet for home appliances, coated with the paint composition. The paint composition includes a thermosetting resin, 9-60 parts by weight of ceramic powder and 0.2-4.0 parts by weight of phosphoric acid, based on 100 parts by weight of the thermosetting resin, is provided, and a precoated metal sheet coated with such a paint composition is also provided. The paint composition and the precoated metal sheet coated with the paint composition manifest high far-infrared emissivity and antibiotic activity, and as well, have storage stability and solvent resistance increased by neutralizing the alkalinity of ceramic powder using phosphoric acid. Further, a silane compound and a curing catalyst are additionally used to increase gloss and processability.

Paint composition having improved far-infrared emissivity, antibiosis and solvent resistance, and precoated metal sheet coated the same

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Pohang, South Korea

Yeong-Sool Jin