| 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+terminating agent+branching agent)x100] 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° C.); and a process for preparing a branched polycarbonate from a dihydric phenol, phosgene or a carbonic acid ester, a branching agent and an terminating agent, characterized by preparing an oligocarbonate, particularly one having chloroformate groups without the addition of the terminating agent, and then reacting the oligocarbonate with the dihydric phenol and the terminating 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.
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