Kuraray Co., Ltd.

Yukio Itoshima

Mamoru Omoda

Mototsugu Yoshihara

Kazuhiko Maekawa

Yukiatsu Komiya

Mitsuru Kato

Shuji Matsunaga

The aqueous dispersion of the present invention is produced by incorporating a block copolymer (II) into an aqueous dispersion (I) of a block copolymer (I) in an aqueous solution containing a basic compound. The block copolymer (I) is composed of a polymer block (A) mainly constituted by a constitutional unit derived from an olefin monomer and a polymer block (B) constituted by a constitutional unit derived from a vinyl monomer (b1) having a carboxyl group, a carboxylic anhydride group or a sulfonic group and a constitutional unit derived from another vinyl monomer (b2) copolymerizable with the vinyl monomer (b1). The content of the basic component is 0.05 equiv or more of the carboxyl group, carboxylic anhydride group or sulfonic group, each contained in the unit derived from the vinyl monomer (b1). The block copolymer (II) is composed of a polymer block (X) mainly constituted by a constitutional unit derived from an aromatic vinyl monomer and a polymer block (Y) constituted by a constitutional unit derived from a conjugated diene monomer. The aqueous dispersion provides a flexible coating film which is excellent in bonding and adhesion properties to various substrates.

Aqueous dispersion including two different block copolymers

The invention provides an aqueous dispersion which includes i) an aqueous dispersion (I) resulting from dispersion of a block copolymer (I) composed of at least one polymer block (A) containing olefin monomer units and at least one polymer block (B) containing 2 to 100 mole percent of units derived from at least one vinyl monomer having a carboxyl or carboxylic anhydride group and 98 to 0 (zero) mole percent of units derived from another vinyl monomer or monomers copolymerizable with the carboxyl group- or carboxylic anhydride group-containing vinyl monomer, in an aqueous solution of not less than 0.05 equivalent, relative to the carboxyl or carboxylic anhydride group, of a basic substance, and ii) a polyurethane (II), iii) vinyl polymer (III) or iv) tackifier (IV) incorporated in the aqueous dispersion (I). The aqueous dispersion of the invention has excellent adhesiveness to various substrates and stability, and gives a coating layer having excellent weather resistance, water resistance and resistance to solvent attack. The aqueous dispersion of the invention is particularly useful as a coating composition and/or a primer.

Aqueous dispersion

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Kurashiki, Japan

Yukio Itoshima