Thermoplastic molding material based on polycarbonate, ASA and vinylaromatics/an-containing copolymers

Claim 1

A thermoplastic molding composition consisting essentially of the following components: A from 45 to 70% by weight of one or more polycarbonates, B from 15 to 30% by weight of one or more graft copolymers, C from 15 to 30% by weight of one or more thermoplastic copolymers containing one or more vinylaromatic monomers of 8 to 12 carbon atoms and acrylonitrile, wherein component B is composed of B 1 a first, coarsely divided graft copolymer which has an average particle size of from 200 to 700 nm (d 50 value of cumulative molecular weight distribution) in a proportion of from 30 to 70% by weight, based on B, and B2 a second, finely divided graft copolymer which has an average particle size of from 50 to 180 nm (d 50 value of cumulative molecular weight distribution) in a proportion of from 70 to 30% by weight, based on B, wherein said first, coarsely divided graft copolymer B 1 is formed from (b 1 ) one or more elastomers (rubbers) which account for from 40 to 80% by weight, based on (B 1 ), and are polymerized from a monomer mixture of (b 1 a 1 ) from 70 to 99.9% by weight, based on (b 1 ), of one or more alkyl acrylates where alkyl is of 1 to 8 carbon atoms (b 1 a 2 ) from 0 to 30% by weight, based on (b 1 ), of one or more further copolymerizable monoethylenically unsaturated monomers and (b 1 a 3 ) from 0.1 to 5% by weight, based on (b 1 ), of a copolymerizable polyfunctional crosslinking monomer, and (b 2 ) a graft sheath on this elastomer, accounting for from 20 to 60% by weight, based on (B 1 ), and being based on (b 2 a 1 ) from 50 to 90% by weight, based on (b 2 ), of one or more monoethylenically unsaturated aromatic hydrocarbons of up to 12 carbon atoms and (b 2 a 2 ) from 10 to 50% by weight of one or more ethylenically unsaturated monomers copolymerizable therewith, wherein said second, finely divided graft copolymer B 2 is formed from (b 1 ) one or more elastomers (rubbers) which account for from 40 to 80% by weight, based on (B 2 ), and are polymerized from a monomer mixture of (b 1 a 1 ) from 70 to 99.9% by weight, based on (b 1 ), of one or more alkyl acrylates where alkyl is of 1 to 8 carbon atoms (b 1 a 2 ) from 0 to 30% by weight, based on (b 1 ), of one or more further copolymerizable monoethylenically unsaturated monomers and (b 1 a 3 ) from 0.1 to 5% by weight, based on (b 1 ), of a copolymerizable polyfunctional crosslinking monomer, and (b 2 ) a graft sheath on this elastomer, accounting for from 20 to 60% by weight, based on (B 2 ), and being based on (b 2 a 1 ) from 50 to 90% by weight, based on (b 2 ), of one or more monoethylenically unsaturated aromatic hydrocarbons of up to 12 carbon atoms and (b 2 a 2 ) from 10 to 50% by weight of one or more ethylenically unsaturated monomers copolymerizable therewith.