PURPOSE: To obtain the titled copolymer having excellent balance among impact resistance, heat resistance, and processability, by converting a specified maleic anhydride-modified graft copolymer into an amidated graft copolymer, and imidating this by ring closure through dehydration.
CONSTITUTION: An aromatic vinyl monomer is emulsion-graft-polymerized with a vinyl cyanide monomer or an acrylic monomer in the presence of a diene rubbery polymer latex. A monomer mixture comprising an aromatic vinyl monomer and maleic anhydride, and optionally other vinyl monomers copolymerizable therewith is graft-polymerized with the above graft copolymer to obtain a modified graft copolymer. This copolymer is reacted with a prim. amine and/or ammonia to obtain an amidated graft copolymer. This copolymer is heated to above 150°C to effect its imidation into a graft maleimide copolymer by ring closure through dehydration.
NAKAGAWA KEIJI
KISHIMOTO AKIHIKO
