POLYMER COMPOSITION OF GRAFT COPOLYMERS OF STYRENE AND ACRYLONITRILE ON A RUBBER

摘要

The invention relates to a polymer composition based on one or more graft copolymers of styrene and acrylonitrile on a rubber and a copolymer of alpha -methylstyrene and acrylonitrile. To improve the flow-properties of such a polymer composition, without unduly decreasing the heat distortion temperature the polymer composition according to the invention is characterized in that it comprises: A. One or more graft copolymers, each of them obtained by polymerizing 20-80 parts by weight of a monomer mixture consisting of 20-40 % by weight of acrylonitrile, 50-80 % by weight of styrene and 0-30 % by weight of one or more other monomers in the presence of 20-80 parts by weight of rubber (in respect of 100 parts by weight of graft copolymer) and B. one or more graft copolymers, each of them obtained by polymerizing 75-90 parts by weight of a monomer mixture consisting of 20-40 % by weight of acrylonitrile, 50-80 % by weight of styrene and 0-30 % by weight of one or more other monomers in the presence of 10=25 parts by weight by rubber (in respect of 100 parts by weight of graft copolymer) and C. a copolymer of alpha -methylstyrene and acrylonitrile obtained by polymerizing 60-80 parts by weight of alpha -methylstyrene and 20-40 parts parts by weight of acrylonitrile, of which polymer composition the rubber content is between 10 and 30 % by weight, while the difference in rubber content of the graft copolymers is at least 5 % by weight.