Abstract: The invention relates to thermoplastic moulding compositions comprising A) between 55 to 98% in weight of at least one vinyl aromatic copolymer modified with a particulate graft rubber, B) between 1 to 44% in weight of a flame retardant comprising B1) an expandable graphite, B2) a flame-retardant compound comprising phosphorus, and B3) a fluorine-containing polymer, C) between 1 to 20% in weight of a non-particulate-forming rubber comprising polar groups, and D) between 0 to 40% in weight of additional additives, where the weight percentages are respectively based on the total weight of components A) to D), and said percentages add up to a total of 100% in weight, and the polybutadiene content is between 0 to 11I % in weight.