Non-chromium rust preventive surface treatment agent for metal members having zinc surface and metal member having zinc surface coated with rust preventive film

摘要

Disclosed is a non-chromium rust preventive surface treatment agent that forms a siliceous film that imparts good rust prevention performance to the zinc surface of a metal member, which is less prone to cracking and peeling. The non-chromium antirust surface treatment agent is an alcohol solution of an alkoxysilane oligomer having a weight average molecular weight of 1,000 to 10,000, and 2.5 to 15% of silicon in the alkoxysilane oligomer molecule is substituted with titanium. Yes. In order to obtain an alkoxysilane oligomer partially substituted with titanium, a titanium compound obtained by chelating approximately half of the alkoxy group of titanium tetraalkoxide is reacted with a tetraalkoxysilane monomer or an alkoxysilane oligomer in an alcohol solution.