Flame Retardants in Commercial Use or in Advanced Development in Polycarbonates and Polycarbonate Blends

The polycarbonates, intrinsically rather flame retardant, have been further flame retarded with various bromoaromatic additives, such as tetrabromobisphenol-A polycarbonate. Other bromine additives used include brominated epoxy condensates and brominated polystyrenes. Sodium or potassium sulfonates, such as potassium perfluorobutylsulfonate, potassium diphenylsulfonesulfonate and sodium trichlorobenzenesulfonate are effective in very low loadings to meet less stringent flame retardancy. The first two allow for transparency. The blends of polycarbonate and poly(acrylonitride butadiene styrene) (ABS) are widely used for flame-retardant electrical and electronic enclosures. The major flame retardants used at present in the blends are tetraphenyl resorcinol diphosphate and tetraphenyl bisphenol-A diphosphonate (both with oligomers).