High impact resistant polycarbonate and process for producing said polycarbonate

A process for producing high impact resistant polycarbonate consisting of a main chain and terminal groups bonded thereto, said main chain comprising a repeating unit represented by the formula (I):

• ##STR5## and at least one of said terminal groups being a cumylphenoxy group represented by the formula (II):
• ##STR6## and having a viscosity average molecular weight of at least 10,000 and an acetone soluble content of not more than 3.5% by weight, which process comprises:
• reacting a polycarbonate oligomer derived from bisphenol A, bisphenol A and cumylphenol in the presence of a tertiary amine catalyst while stirring so that the reaction mixture is in a turbulent flow condition;
• adding an aqueous solution of alkali hydroxide at the point of time that the viscosity of the reaction mixture increases;
• and
• subsequently continuing the reaction in a laminar flow condition;
• and wherein the proportion of each component is chosen within the following ranges:
• 0. 04/1<b/a<0.17/1,
• 0.40/1<c/a<0.55/1,
• 2.01/1<d/c<2.50/1,
• 1.40/1<(d+e)/a<1.60/1,
• 1.0.times.10.sup.-3 <f/a<5.0.times.10.sup.-3
• wherein
• a=mole number of the chloroformate group of the polycarbonate oligomer,
• b=mole number of cumylphenol,
• c=mole number of bisphenol A,
• d=mole number of alkali hydroxide contained in an aqueous alkali hydroxide solution in which bisphenol A is dissolved,
• e=mole number of alkali hydroxide contained in an aqueous alkali hydroxide solution to be added at the point of time that the flow of the reaction mixture is changed from a turbulent flow to a laminar flow, and
• f=mole number of the tertiary amine.