POLYVINYL ACETAL/POLYESTER GRAFT COPOLYMER, AND DISPERSANT

摘要

A polyvinyl acetal/polyester graft copolymer obtained from a polyvinyl acetal having one or more of each of constituent units represented by the following general formulae (1) to (3) (wherein each of R 1 and R 2 represents a hydrogen atom, a linear or branched alkyl group having a carbon number of from 1 to 20, or an aryl group, in which the alkyl group or the aryl group may have a substituent) and having a weight average molecular weight of from 100 to 100, 000 is used as a dispersant which prevents aggregation of solid particles in a dispersion liquid from occurring, is effective for forming a stable dispersion liquid, and exhibits excellent heat resistance. The graft copolymer is one in which a polyvinyl acetal and a polyester having at least one carboxyl group at an end of a main chain thereof and having a weight average molecular weight of from 100 to 50,000 are allowed to react with each other to form a graft bond with from 1 to 95 % by mole of a hydroxyl group of the polyvinyl acetal; one in which a lactone in an amount of from 1 to 50 molar equivalents to a hydroxyl group which the polyvinyl acetal has is subjected to addition polymerization; or one in which from 1 to 95 % by mole of a hydroxyl group which the polyvinyl acetal has forms a bond by an ester exchange reaction with the polyester.