Patent ID: 8906995

Claim:
An impact resistant polycarbonate composition having improved resistance to polymer degradation comprising an aromatic polycarbonate in admixture with an elastomer-modified graft copolymer that is the product of an emulsion polymerization process, the composition further comprising metallic salts of phosphoric acid, at least one of which is a potassium salt of phosphoric acid, wherein the metallic salts of phosphoric acid are present in the composition in an amount that provides a phosphorus content of 0.01 to 0.16 mol/10 lbs (0.0022 to 0.035 mol/kg), based on the weight of the composition, wherein the metallic salts of phosphoric acid comprise a weak acid form and a conjugate base form and wherein the weak acid and conjugate base are pairs selected from the group consisting of monopotassium phosphate/dipotassium phosphate, lithium phosphate monobasic/dipotassium phosphate, aluminum phosphate monobasic/dipotassium phosphate, monozinc phosphate/dipotassium phosphate, and combinations thereof; and wherein after aging molded ISO T-bars of the composition in an oven for 1000 hours at 90±2° C. and 95±3% RH, the melt flow rate (MFR) of the polycarbonate composition does not change by more than 5.0 g/10 minutes units measured in accordance with ISO 1133 standard at 230° C. using a 3.8 kg load and 300 sec dwell time.