Gasoline-resistant thermoplastic molding compounds

A thermoplastic molding composition comprising a blend of

• A) 40 to 48 parts by weight of a thermoplastic aromatic polycarbonate resin,
• B) 30 to 40 parts by weight of a graft polymer containing
• B.1) 5 to 90 parts by weight of a mixture of
• B.1.1) 50 to 95% by weight of at least one member selected from the group consisting of styrene, .alpha.-methyl styrene, ring-substituted styrene and methyl methacrylate, and
• B.1.2) 5 to 50% by weight of at least one member selected form the group consisting of acrylonitrile and methacrylonitrile, grafted on `B.2) 95 to 10 parts by weight of a particulate rubber having an average particle diameter of 0.09 to 5 .mu.m,
• C) 10 to 25 parts by weight of a thermoplastic copolymer having a weight average molecular weight in the range of 15,000 to 200,000 (as measured by light scattering or sedimentation) of (i) or (ii), where
• (i) is from 50 to 95% by weight of at least one member selected from the group consisting of styrene, .alpha.-methylstyrene, ring substituted styrene and methyl methacrylate and from 50 to 5% by weight of at least one member selected from the group consisting of (meth)acrylonitrile, maleic anhydride and N-substituted maleic imide and
• (ii) is form 50 to 95% by weight of at least one member selected from the group consisting of styrene, .alpha.-methylstyrene, ring substituted styrene, and from 50 to 5% by weight of (meth)acrylonitrile, methylmethacrylate, maleic anhydride and N-substituted maleic imide and
• D) 1 to 10 parts by weight of a graft polymer of polycarbonate chains on a copolymer graft base which has been prepared by copolymerizing 95 to 99.5 mol styrene and 5 to 0.5 mol of a compound corresponding to formula (I) ##STR7## in which R=H or C.sub.1-4 alkyl,
• R.sub.1 =Cl, Br, C.sub.1-4 alkyl, cyclohexyl or C.sub.1-4 alkoxy,
• m=0 to 1,
• n=0, 1 or 2,
• r=0 or 1,
• t=0 or 1 and
• X=--O--Si(CH.sub.3).sub.3,
• by radical-initiated bulk polymerization to a number average molecular weight in the range of 45,000 to 95,000 and subsequently subjecting this copolymer graft base without isolation to reaction with diphenols, phosgene and monophenols in an aqueous-alkaline phase in the presence of an inert organic solvent under the conditions of a two-phase interfacial polycondensation process to obtain a graft polymer having a content of polycarbonate chains of 65 to 45 percent by weight, said polycarbonate chains having a degree of polycondensation of 35 to 70 said process being characterized in that the final viscosity of the organic phase of the reaction mixture is from 5 to 25 mPa.s.