Block copolymers, dispersants, and coloring compositions

Abstract

This invention provides a block copolymer that is UV-curable and exhibits high dispersion performance of the coloring material when used as a dispersant in a coloring composition. In the ABC-type triblock copolymer of this invention, blocks A through C are formed by free radical polymerization of polymerizable compositions (A) through (C), respectively. Polymerizable composition (A) contains (meth)acrylates having hydroxyl groups and / or (meth)acrylates having alkoxy groups; polymerizable composition (B) contains a vinyl monomer (b-1) having a nitrogen-containing functional group; and polymerizable composition (C) contains a vinyl monomer (c-1) having (meth)acrylic and vinyl unsaturated groups. The molar volume ratio (X / Y) of the structural unit (X) derived from the monomer (c-1) and having vinyl unsaturated groups relative to the structural unit (Y) derived from the vinyl monomer (b-1) is 0.1 to 1.1.