Patent ID: 7968671

Claim:
Copolycarbonates comprising: (i) a chain terminator structural unit of the formula (1): wherein R1 and R2 each independently represent hydrogen or a C 1-18 -alkyl, with the proviso that R1 and R2 are not simultaneously hydrogen; (ii) at least one diphenol unit of the formula (2) wherein R 3 represents a C 1-4 -alkyl, R 4 represents hydrogen or C 1 -C 4 -alkyl, and n represents 0, 1, 2 or 3; and (iii) at least one dihydroxyaryl compound of the formula (3) HO—Z—OH (3) wherein Z represents a radical of the formula (3a) wherein each R 6 and each R 7 independently represents a moiety selected from the group consisting of H, C 1 -C 18 -alkyls, C 1 -C 18 -alkoxys, halogens, optionally substituted aryls or aralkyls, and X represents a moiety selected from the group consisting of —SO 2 —, —CO—, C 1 - to C 6 -alkylenes, C 2 - to C 5 -alkylidenes and C 6 - to C 12 -arylenes, optionally condensed with further aromatic rings containing hetero atoms; wherein the copolycarbonates have an inhomogeneity factor of: A) 1.3 to 2.5, when the copolycarbonates have a content of ≧50 mol % and <100 mol % of the at least one diphenol unit of the formula (2), based on total diphenols, and have an average molecular weight (weight-average) of 18,000 to 35,000 g/mol; and B) 1.2 to 2.4, when the copolycarbonates have a content of greater than 0 and less than 50 mol % of the at least one diphenol unit of the formula (2), based on total diphenols, and have an average molecular weight (weight-average) of 16,000 to 35,000 g/mol.