POLYVINYL ACETAL/POLYESTER GRAFT COPOLYMER, AND DISPERSANT

摘要

A polyvinyl acetal/polyester graft copolymer obtained from a polyvinyl acetal having a weight-average molecular weight of 100 to 100,000, and one or more of each of the structural units represented by general formula (1) to (3) (wherein, R1 and R2 represent a hydrogen atom, a straight-chain or branched alkyl group having 1 to 20 carbon numbers, or an aryl group; the alkyl group and the aryl group may have a substituent group) is used as a dispersant which: prevents solid particles within a dispersion liquid from clumping together; is effective in forming a stable dispersion liquid; and exhibits excellent heat resistance. Said graft copolymer is either one in which a graft bond is formed with 1 to 95 mol% of a hydroxyl group of a polyvinyl acetal by means of a reaction between a polyvinyl acetal and a polyester which has at least one carboxyl group at the end of the main chain, and a weight average molecular weight of 100 to 50,000; one in which a lactone in the amount of 1 to 50 molar equivalents in relation to the hydroxyl group of a polyvinyl acetal is additionally polymerized on the graft copolymer; or one in which 1 to 95 mol% of the hydroxyl group of the polyvinyl acetal forms a bond with polyester by means of an ester exchange reaction.