Nippon A&l Incorporated

Akira Kamimura

Toshiyasu Nishioka

Makoto Itagaki

A copolymer latex for chipping-resistant aqueous paint capable of remarkably improving balance of chipping-resistance, strength of adherence with metal, water-resistance and high resistance for cycles of cool and heat is provided. This is achieved by a method for producing a copolymer latex using for chipping-resistant aqueous paint, the method comprising emulsion-polymerizing 20 to 80 parts by weight of a conjugated diene as a monomer, 0.5 to 15 parts by weight of an ethylenically unsaturated carboxylic acid as a monomer, 5 to 40 parts by weight of an aromatic vinyl compound as a monomer, 5 to 40 parts by weight of an unsaturated alkyl carboxylate as a monomer and optionally not more than 69.5 parts by weight of other compound having vinyl group copolymerizable therewith as a monomer based on 100 parts by weight in the total of the monomers, wherein 100 wt % of the amount of conjugated diene, 100 wt % of the amount of ethylenically unsaturated carboxylic acid, 95 to 50 wt % of the amount of aromatic vinyl compound and 95 to 50 wt % of the amount of the unsaturated alkyl carboxylate are added in the former stage of the emulsion-polymerization, and 5 to 50 wt % of the amount of the aromatic vinyl compound and 5 to 50 wt % of the amount of the unsaturated alkyl carboxylate are added at the later stage of emulsion-polymerization.

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Konohana-ku, Japan

Akira Kamimura