Flame retardant thermoplastic polycarbonate compositions, method of manufacture, and method of use thereof

A thermoplastic composition comprising in combination

• from about 40 to about 90 wt. % of a polycarbonate component;
• from about 5 to about 40 wt. % of a polycarbonate-polysiloxane copolymer;
• from about 1 to about 20 wt. % of an impact modifier
• wherein the impact modifier comprises a rubber modified thermoplastic resin comprising a discontinuous elastomeric phase dispersed in a rigid thermoplastic phase, wherein at least a portion of the rigid thermoplastic phase is grafted to the elastomeric phase, and wherein the rubber modified thermoplastic resin employs at least one rubber substrate for grafting and the rubber substrate comprises the discontinuous elastomeric phase of the composition, further wherein the rubber substrate must be susceptible to grafting by at least a portion of a graftable monomer and the rubber substrate is derived from polymerization by known methods of at least one monoethylenically unsaturated (C1-C12)alkyl(meth)acrylate monomers and mixtures comprising at least one of the monomers, and wherein the rigid thermoplastic phase comprises an alkenyl aromatic polymer having structural units derived from one or more alkenyl aromatic monomers and from one or more monoethylenically unsaturated nitrile monomers;
• and
• from about 1 to about 30 wt. % of a flame retardant.

A thermoplastic composition comprising in combination

• from about 50 to about 70 wt. % of a polycarbonate component;
• from about 10 to about 25 wt. % of a polycarbonate-polysiloxane copolymer;
• from about 1 to about 10 wt. % of an impact modifier
• wherein the impact modifier comprises a rubber modified thermoplastic resin comprising a discontinuous elastomeric phase dispersed in a rigid thermoplastic phase, wherein at least a portion of the rigid thermoplastic phase is grafted to the elastomeric phase, and wherein the rubber modified thermoplastic resin employs at least one rubber substrate for grafting and the rubber substrate comprises the discontinuous elastomeric phase of the composition, further wherein the rubber substrate must be susceptible to grafting by at least a portion of a graftable monomer and the rubber substrate is derived from polymerization by known methods of at least one monoethylenically unsaturated (C1-C12)alkyl(meth)acrylate monomers and mixtures comprising at least one of the monomers, and wherein the rigid thermoplastic phase comprises an alkenyl aromatic polymer having structural units derived from one or more alkenyl aromatic monomers and from one or more monoethylenically unsaturated nitrile monomers;
• from about 6 to about 16 wt. % of a flame retardant;
• and
• from about 0.2 to about 1 wt. % of TSAN;
• wherein the composition is capable of achieving a UL94 rating of V1 at a thickness of 0.5 mm or less.