Patent ID: 7057005

Claim:
A process for producing a branched polycarbonate composition from dihydric phenol, carbonate precursor, multifunctional phenolic branching agent and monophenolic chain terminator using a coupling catalyst which process comprises the addition of coupling catalyst at separate, different points in the process according to the sequential steps of: a) combining a dihydric phenol, a tri- or higher functional hydric compound branching agent, base and water to form the reaction mixture, b) then adding at least part of the carbonate precursor and the water immissible organic solvent and reacting the polymerization mixture, partially oligomerizing the dihydric phenol, c) then adding (i) a monophenolic chain terminator and; (ii) a part of the coupling catalyst in an amount of at least about 0.5% of the total coupling agent amount; and (iii) base to the reaction mixture, d) adding the balance of the carbonate precursor (if any) and continuing the reaction of the polymerization mixture, e) adding the balance of the coupling catalyst separate from and after the addition of the first coupling catalyst amount added in step c) after the molecular weight (Mw) of the polymer is at least about 10,000 g/mole, f) completing the polymerization reaction.