A process for preparing a polymer composition based on one or more graft copolymers of styrene and acrylonitrile on a rubber.

摘要

The invention relates to a heat resistant polymer composition based on one or more graft copolymers of styrene and acrylonitrile on a rubber and a copolymer of alpha -methylstyrene and acrylonitrile. This composition comprises: A. A graft copolymer obtained by polymerizing 50-80 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 20-50 parts by weight of rubber (in respect of 100 parts by weight of graft copolymer) and B. a copolymer of alpha -methylstyrene and acrylonitrile obtained by polymerizing a mixture of 60-80 parts by weight of alpha -methylstyrene and 20-40 parts by weight of acrylonitrile, of which copolymer the spiral flow length (S) is at least 65 and the flow index (V) 45 at most, and the ratio between spiral flow length and the flow index is at least 3.0, and in which polymer composition 35 to 80% by weight of copolymer of alpha -methylstyrene and acrylonitrile is present.