Patent attributes
It is a task of the present invention to provide a method which enables the production of a high quality, high performance aromatic polycarbonate (which is colorless and has excellent mechanical properties) from a molten aromatic polycarbonate prepolymer obtained from an aromatic dihydroxy compound and a diaryl carbonate, wherein the polycarbonate can be stably produced on a commercial scale at 1 to 50 t/hr for a long time without the need for a large amount of an inert gas. In the present invention, this task has been accomplished by a method for producing an aromatic polycarbonate by the melt transesterification process, in which the prepolymer is caused to absorb a specific amount of an inert gas, followed by polymerization using a guide-wetting fall polymerizer device having a specific structure, whereby a high quality, high performance aromatic polycarbonate as mentioned above can be stably produced on a commercial scale at 1 to 50 t/hr for a long time (more than several thousand hours, e.g., as long as 5,000 hours) without fluctuation of the molecular weight thereof.
