Ageing-resistant thermoplastic moulding mass with a high notch impact strength and surface quality

Claim 1

Thermoplastic moulding compounds of a) from 20 - 80 parts by weight of thermoplastic homo- or copolymers of monomers of styrene, α-methylstyrene, acrylonitrile, maleic acid derivatives, methyl methacrylate or mixtures thereof and b) from 80 - 20 parts by weight of a graft product of b1) from 10 - 70% by weight of a particulate cross-linked rubber having an average particle diameter (d₅₀) of from 0.08 to 1 µm as the graft basis and b2) from 90 to 30% by weight of a homo- or copolymer of styrene, α-methylstyrene, acrylonitrile, maleic acid derivatives, methyl methacrylate or mixtures thereof as graft, characterised in that the rubber b1) is a combination of silicone rubber and acrylate rubber, the cross-linked acrylate rubber enclosing the cross-linked silicone rubber particles, the ratio by weight of silicone rubber to acrylate rubber is from 90 : 10 to 50 : 50 and the graft product b) is prepared in aqueous emulsion by polymerisation of the monomers b2) in the presence of an emulsion of the rubber b1) and a redox initiator system.