Resin composition for cationically electrodepositable paint containing finely divided gelled polymer based on radically polymerizable hydrolyzable silane monomers

摘要

A resin composition for cationically electrodepositable paint comprising, as principal components, (A) a resin containing a hydroxyl group and a cationic group, (B) an epoxy resin containing, per molecule, on the average at least 2 epoxy group-containing functional groups with an epoxy group bound to an alicyclic skeleton and/or a bridged alicyclic skeleton, and (C) a finely divided gelled polymer, said finely divided gelled polymer (C) being obtained by, in the first step, emulsion polymerizing (I) a monomer component composed ofPP(a) a polymerizable unsaturated vinylsilane monomer containing a vinylic double bond and a hydrolyzable alkoxysilane group,PP(b) a polymerizable monomer containing at least two radically polymerizable unsaturated groups in a molecule,PP(c) a polymerizable unsaturated monomer containing a vinylic double bond and a hydroxyl group, andPP (d) the other polymerizable unsaturated monomer using a cationic reactive emulsifying agent containing an allyl group in a molecule; and in the second step, emulsion polymerizing (II) a monomer component composed ofPP(e) a blocked monoisocyanate or polyisocyanate in which at least one isocyanate group in a molecule is blocked with a radically polymerizable monohydroxy compound,P P(f) a polymerizable unsaturated monomer containing a vinylic double bond and a hydroxyl group, andPP (g) the other polymerizable unsaturated monomer in the presence of the aqueous finely divided gelled polymer obtained in the first step, said polymer having a core-sheath structure in which the polymerized product of the monomer component (I) is a core and the polymerized product of the monomer component (II) is a sheath (shell).