MODIFIED POLYESTER FIBER AND METHOD FOR PRODUCING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a modified polyester fiber, in which a carboxyl group hard to be hydrolyzed, having slight change in strength with time. SOLUTION: This modified polyester fiber in which carboxyl group is introduced is obtained by carrying out graft polymerization of a polyester fiber with an unsaturated carboxylic acid in the presence of a phthalimide represented by the following general formula (1) (wherein R is hydrogen or a 1-6C alkyl group).