Flame-resistant polycarbonate ABS molding materials

A flame-resistant, thermoplastic molding composition containing:

• A 5 to 95 parts by weight of a mixture of two aromatic polycarbonates A.1 and A.2 with different solution viscosities, wherein
• 1. the relative solution viscosity of A.1 is 1.18 to 1.24,
• 2. the relative solution viscosity of A.2 is 1.24 to 1.34, and
• 3. the difference between the relative solution viscosities of A.1 and A.2 is equal to or greater than 0.06, wherein one or more further polycarbonates may be added to the mixture of A.1 and A.2, the relative solution viscosities of A.1 and A.2 being measured in CH2Cl2 at 25° C. and at a concentration of 0.5 g/100 ml;
• B 0 to 50 parts by weight of a (co)polymer consisting of 1 or at least 2 ethylenically unsaturated monomers selected from styrene, α-methylstyrene, ring-substituted styrenes, acrylonitrile, methacrylonitrile, methyl methacrylate, maleic anhydride, N-substituted maleic imide and (meth)acrylates with 1 to 18 carbon atoms in the alcohol component;
• C 0.5 to 60 parts by weight of graft polymer, obtainable by graft polymersation of at least two monomers selected from the group consisting of chloroprene, 1,3-butadiene, isoprene, styrene, acrylonitrile, ethylene, propylene, vinyl acetate and (meth)acrylates with 1 to 18 carbon atoms in the alcohol component;
• D 0.5 to 20 parts by weight of a phosphorous compound of the formula (I)
• in which
• R1, R2 R3 and R4, independency of each other, represent an optionally halogenated C1-C8 alkyl group, or a C5-C6 cycloalkyl, C6-C20 aryl or C7-C12 aralkyl group, each optionally substituted by at least one of halogen and C1-C4 alkyl groups,
• n each, independently, represents 0 or 1,
• N is 0 to 30, and
• X represents a mono or polynuclear aromatic group with 6 to 30 carbon atoms;
• E 0.05 to 5 parts by weight of a fluorinated polyolefin;
• and
• F 0.01 to 50 parts by weight per 100 parts by weight of A to E of a very finely divided inorganic compound with an average particle diameter of less than or equal to 200 nm, said inorganic compound being selected from Al2O3, AlO(OH), zinc borate and mixtures thereof,
• wherein the sum of the parts by weight of A to F is 100 parts by weight.