Nihon Parkerizing Co., Ltd.

Mitsubishi Kasei Corporation

Akira Nishihara

Hiroshi Okita

Takao Ogino

Takumi Honda

Noriaki Yoshitake

Ryosuke Sako

Kenshi Saeki

Yukio Tsuge

Akihiko Hasebe

Haruo Iizuka

Ryohsuke Sako

Yoshinori Sakamoto

Motoki Kanazawa

The present invention relates to a process for surface treatment for cathodic electrodeposit coating of a zinc-plated or zinc alloy-plated steel sheet comprising coating and drying a protective coating material on said steel sheet chromate-treated beforehand, to form a protective film before subjecting the sheet to the cathodic electrodeposit coating, which comprises coating a protective coating material having as a principal constituent of film-forming organic component a block isocyanate-containing prepolymer containing in one and the same molecule respectively at least one blocked isocyanate group, hydroxyl group, and tertiary amono group and containing 10-100 parts by weight of silica sol relative to 100 parts by weight of said prepolymer, in an amount of 0.3 g-4 g/m.sup.2, and then heat-drying the same.

Process for treating plated steel sheet

A durable hydrophilic surface can be formed on metals by coating them with a composition containing a first water soluble polymer based on polyacrylamide, a second water soluble polymer with at least 60 mole percent of ionizable groups such as acids and quaternary ammonium salts, and a cross linking agent. Water soluble chromium and zirconium salts that can form complexes with the first water soluble polymer are preferred crosslinking agents. The invention is particularly useful for aluminum to be used in heat exchangers.

Metal surface hydrophilicizing process and composition

A hydrophilic coating is formed on an aluminum surface by the application of an aqueous solution of an amphoteric acrylamide polymer which is dried in place. The polymer solution may contain a cross-linking agent and the dried coating may be subsequently treated to form a water-glass coating.

Method for hydrophilic treatment of aluminum using an amphoteric polymer

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Yokohama, Japan

Akira Nishihara