A PROCESS FOR PRODUCING A RUBBER-MODIFIED THERMOPLASTIC RESIN

摘要

A rubber-modified thermoplastic resin is produced by graft-copolymerizing an aromatic alkenyl compound, an alkenyl cyanide and a methacrylic acid ester onto an ethylene-propylene rubber. The polymerization is carried out in two steps. In the first step, the aromatic alkenyl compound and the alkenyl cyanide (optionally with up to 20% by weight of at least one other copolymerizable monomer) are graft-copolymerized onto the rubber until the polymerization conversion has reached a value within the range from 30 to 70% by weight. In the second step, a methacrylic acid ester (optionally in admixture with up to 20% by weight of at least one copolymerizable monomer) is polymerized in the presence of the reaction mixture from the first reaction step, until polymerization is substantially complete. The resulting resin has excellent impact resistance and colourability and produces a moulded article having good appearance.