| US 7,588,801 B2 | ||
| Chromium-free rust inhibitive treatment method for metal products having zinc surface and metal products treated thereby | ||
| Yasuhiko Endo, Yokohama (Japan); Kengo Takase, Kasugai (Japan); Shunjiro Watanabe, Aichi (Japan); and Shoichiro Adachi, Ogaki (Japan) | ||
| Assigned to Hoden Seimitsu Kako Kenkyusho Co., Ltd., Atsugi (Japan) | ||
| Filed on Dec. 13, 2007, as Appl. No. 11/956,020. | ||
| Application 11/956020 is a division of application No. 11/334552, filed on Jan. 19, 2006, abandoned. | ||
| Claims priority of application No. 2005-014988 (JP), filed on Jan. 24, 2005. | ||
| Prior Publication US 2008/0102212 A1, May 01, 2008 | ||
| Int. Cl. B05D 1/36 (2006.01) | ||
| U.S. Cl. 427—387 [427/388.1; 427/388.5; 427/409; 148/240; 148/243; 148/253; 148/256; 148/257] | 6 Claims |
| 1. A chromium-free rust inhibitive treatment method for a metal product having a zinc surface comprising:
coating the zinc surface of the metal product with an aqueous chromium-free conversion coating liquid to form a conversion-coated
film on the zinc surface and
applying a solution of a chromium-free surface treatment agent to the surface coated with the conversion coated film to form
a siliceous film having an average thickness of 0.5 to 3 μm on the surface coated with the conversion coated film, the solution
of the chromium-free surface treatment agent being alkoxysilane oligomer in an alcohol solvent and containing a component
that changes into silica of 10 to 25% by weight as an amount converted to silica,
wherein the alkoxysilane oligomer has been prepared by hydrolysis and condensation polymerization of tetraalkoxysilane together
with acid catalyst, and the weight averaged molecular weight of the alkoxysilane oligomer is 1000 to 10000.
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