Flame retardant resin compositions containing phosphoramides, and method for making

A method to increase the heat distortion temperature of a flame resistant composition containing an amount of at least one phosphoramide effective to render the composition a flame rating of at least V-2 in the Underwriter's Laboratory UL-94 protocol when measured on a test specimen of about 0.125 inch by about 0.5 inch by about 5 inch dimensions, wherein the method comprises combining

• (a) at least one thermoplastic resin selected from the group consisting of (i) polycarbonate resins and blends containing at least one polycarbonate resin, (ii) polyphenylene ether resins and blends containing at least one polyphenylene ether resin, (iii) polystyrene resin and blends containing polystyrene resin, (iv) styrene-containing copolymer resin and blends containing styrene-containing copolymer resin;
• (v) styrene-containing graft copolymer resin and blends containing styrene-containing graft copolymer resin;
• and (vi) high impact polystyrene resin and blends containing high impact polystyrene resin, and
• (b) at least one phosphoramide having a glass transition point of at least about 0° C. of the formula VI:
• wherein each Q1 is independentlyoxygen or sulfur;
• and each of A3-6 is independently an alkyloxy, alkylthio, aryloxy, or arylthio residue, or an aryloxy or arylthio residue containing at least one alkyl or halogen substitution, or mixture thereof;
• or an amine residue.