Heat and impact resistant resin composition

Claim 1

A heat and impact resistant resin composition which comprises from 10 to 90 parts by weight of a copolymer (A) comprising from 90 to 50% of residues of a vinyl aromatic compound selected from the group consisting of styrene, α-methylstyrene, p-methylstyrene, t-butylstyrene and a halogenated styrene, from 10 to 50% of residues of a maleimide compound and from 0 to 30% of residues of a vinyl compound copolymerizable therewith; from 0 to 50 parts by weight of a copolymer (B) comprising from 90 to 40% of residues of a vinyl aromatic compound as defined above and from 10 to 60% of residues of an unsaturated nitrile compound selected from the group consisting of acrylonitrile, methacrylonitrile and a mixture thereof; from 5 to 89 parts by weight of a graft copolymer (C) produced by polymerizing from 25 to 70% by weight of particles of a rubber latex selected from the group consisting of polybutadiene, a styrene-butadiene copolymer, an acrylonitrile-butadiene copolymer, a homopolymer or copolymer of an alkyl acrylate, an ethylene-propylene copolymer and an ethylene propylene-non-conjugated diene terpolymer, said rubber latex having a glass transition temperature of not higher than 0° C. and an average particle size of from 0.1 to 0.5 μm with from 75 to 30% by weight of a resin comprising from 90 to 40% of residues of the vinyl aromatic compound as defined for copolymer (A) and from 10 to 60% of residues of an unsaturated nitrile compound selected from the group consisting of acrylonitrile, methacrylonitrile and a mixture thereof; and from 1 to 45 parts by weight of a graft copolymer (D) produced by polymerizing from 2 to 17% by weight of particles of a rubber latex as defined above having a glass transition temperature of not higher than 0° C. and an average particle size of from 0.7 to 4 μm, with from 98 to 83% by weight of a resin comprising from 90 to to 40% of residues of the vinyl aromatic compound as defined for copolymer (A) and from 10 to 60% of residues of the unsaturated nitrile compound as defined for graft copolymer (C), wherein the amount of the graft copolymer (C) is from 97 to 50% by weight of the total amounts of the graft copolymers (C) and (D).