Patent ID: 7601778

Claim:
An aqueous dispersion which 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, wherein: the block copolymer (I) is a diblock copolymer 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 olefin monomer comprises at least one monomer selected from the group consisting of ethylene, α-olefins, 2-butene, isobutylene, conjugated dienes, vinylcyclohexane and β-pinene; when the olefin monomer comprises a conjugated diene, the polymer block (A) is a block in which the unsaturated bonds of the constitutional units derived from conjugated dienes are hydrogenated; a content of the basic compound is 0.05 equiv or more of the carboxyl group, carboxylic anhydride group or sulfonic group contained in the unit derived from the vinyl monomer (b1); and 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.