Patent ID: 7691926

Claim:
A 4,4′-biphenol polysulfone composition comprising a synergistic melt stability enhancing combination of: at least 60% by weight, based on total weight of the composition, of at least one polysulfone comprising more than 50 mol. % of recurring units formed by reacting 4,4′-biphenol with at least one sulfone monomer SM 1 (B ol PSU); more than 0.01% by weight, based on the total weight of the composition, of at least one phosphorus-containing compound consisting of (a) one or more organic phosphites and one or more organic phosphonites; or (b) tris(2,4-di-t-butyl-phenyl)phosphate; or (c) tris(2.4-di-t-butyl-phenyl)phosphite and one or more organic phosphonites; and at least 1% by weight, based on total weight of the composition, of at least one polysulfone comprising more than 50 mol. % of recurring units formed by reacting bisphenol A with at least one sulfone monomer SM 2 (B ol A PSU).