Method of preparing an acrylic copolymer having an acid anhydride group

Abstract

The present invention is a method of preparing an acrylic copolymer having an acid anhydride group with a number average molecular weight of 1,500-5,000 comprising; polymerizing a monomer mixture of a radical polymerizable monomer having an acid anhydride group and another radical polymerizable monomer at a temperature of 150° C. or higher by using a radical initiator, wherein the concentration of the monomer mixture is 50-75 wt %. This method can provide an acrylic copolymer having an acid anhydride group with a relatively low molecular weight that does not cause the problem of yellowing after baking when used in an acid/epoxy curing type clear paint, by means of high temperature polymerization without the use of a large amount of an expensive initiator.

Dependencies are inferred from the claim text.