| abstract |
A water-based surface-treating agent which comprises an acrylic resin, water, and colloidal silica having a solid concentration of 5 to 35 wt.%, characterized in that the acrylic resin is a polymer having a glass transition temperature of 0 to 30 DEG C obtained by polymerizing (a) 15 to 76 wt.% unsaturated (meth)acrylic ester monomer represented by the following general formula (1) (1) (wherein R<1> is hydrogen or methyl and R<2> is C1-8 linear or branched alkyl), (b) 2 to 10 wt.% a, beta -ethylenically unsaturated monomer having a carboxyl group in the molecule, (c) 2 to 10 wt.% alpha , beta -ethylenically unsaturated monomer having a hydroxyl group in the molecule, (d) 10 to 30 wt.% styrene, (e) 10 to 30 wt.% acrylonitrile, and (f) 0 to 10 wt.% unsaturated monomer copolymerizable with these monomers. Also provided is a surface-treated metallic material produced with the agent. |