Patent ID: 7259223
Filing Date: 2007-08-21
Classification: C08G

Abstract:
1. A process for the production of an aromatic polycarbonate, the process comprising adding to a polycarbonate oligomer reaction mixture comprising polycarbonate with free hydroxy groups under melt conditions an amount of a terminal blocking agent of the following formula: to form a polycarbonate having an increased level of capped or blocked hydroxy groups, wherein at least 80% of the blocking agent is added after the oligomer has reached a number-average molecular weight Mn of about 2,500 to 15,000 Dalton, and wherein R 1 is a propoxy or butoxy and R 2 is selected from the group consisting of C 1 -C 30 alkyl, C 1 -C 30 alkoxy, C 6 -C 30 aryl, C 7 -C 30 aralkyl, and C 6 -C 30 aryloxy.