BRANCHED POLYCARBONATE RESIN AND PROCESS FOR THE PREPARATION THEREOF

摘要

A branched polycarbonate resin which is prepared by using a tetrahydric phenol having a specific structure as the branching agent, has a branching agent content [branching agent/(dihydric phenol + end-capping agent + branching agent) x 100] of 0.05 to 0.5 mole % and satisfies the relationship: y >/= 11x + 0.5 (wherein x is the branching agent content of the resin; and y is the melt tension (g) thereof at 280 DEG C); and a process for preparing a branched polycarbonate from a dihydric phenol, phosgene or a carbonic acid ester, a branching agent and an end-capping agent, characterized by preparing an oligocarbonate, particulary one having chloroformate groups without the addition of the end-capping agent, and then reacting the oligocarbonate with the dihydric phenol and the end-capping agent. This process can provide a branched polycarbonate which is lowered in the branching agent content, exhibits a high melt tension and good melt characteristics, and can be stably molded through blow molding, extrusion, vacuum forming and so on.