摘要 |
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 amino 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<2>, and then heat-drying the same. |
申请人 |
NIHON PARKERIZING CO., LTD., TOKIO/TOKYO;MITSUBISHI KASEI CORP., TOKIO/TOKYO |
发明人 |
SAEKI, KENSHI, KURASHIKI-SHI;OGINO, TAKAO, HIRATSUKA-SHI;YOSHITAKE, NORIAKI, HIRATSUKA-SHI;HONDA, TAKUMI, HIRATSUKA-SHI;NISHIHARA, AKIRA, YOKOHAMA-SHI;OKITA, HIROSHI, YOKOSUKA-SHI;TSUGE, YUKIO, EBINA-SHI;IIZUKA, HARUO, ATSUGI-SHI |