US Patent 7649051 Flame retardant thermoplastic polycarbonate compositions

A flame retardant thermoplastic composition comprising in combination a polycarbonate component; an impact modifier composition, the components of the impact modifier composition comprising a) a bulk polymerized ABS, and b) an impact modifier different from the ABS; an ungrafted rigid copolymer; and a flame retardant. The compositions have an improved balance of physical properties such as impact strength and flow, while at the same time maintaining their good flame performance.