Process for making polypropylene graft copolymers containing anhydride groups

摘要

A graft copolymer containing anhydride groups is made by (1) making a graft copolymer comprising a backbone of a propylene polymer material having graft polymerized thereto polymerized monomers selected from the group consisting of (a) at least one acrylic acid substituted with a 1-3 C alkyl group and (b) a mixture of at least one of these substituted acrylic acids and a vinyl compound capable of copolymerizing therewith, wherein the total amount of polymerized monomers is about 20 parts to about 240 parts per hundred parts of the propylene polymer material and the amount of the substituted acrylic acid is 60 mole % or more of the polymerized monomers, and (2) heating the graft copolymer to a temperature of about 170 DEG C. to about 300 DEG C. to dehydrate the acid groups in the graft copolymer to form anhydride groups.