Thermoplastic moulding materials based on special graft rubber components

Composition comprising

• A) at least one elastic-thermoplastic graft polymer obtained by free-radical emulsion polymerization of resin-forming vinyl monomers in the presence of rubber which is in latex form and has a glass transition temperature of ≦0° C., using a redox initiator system and
• B) at least one copolymer built up from styrene and acrylonitrile and optionally further comonomers
• and optionally
• C) a resin chosen from the group consisting of polycarbonates, polyester-carbonates, polyesters and polyamides,
• characterized in that the preparation of the graft polymer A) is carried out by a procedure in which before the start of the grafting polymerization reaction the rubber latex is brought to a pH of 9 to 11 and the pH remains constant during the reaction within a range of variation of ±0.5 units, the redox initiator components are employed in amounts of 0.1 to 2.5 wt. % (based on the monomers metered in) and during the entire grafting polymerization reaction the pH should not exceed a value of 11.0 and should not fall below a value of 8.8, and the temperature difference between the start and end of the reaction is at least 10° C.