Production method of polycarbonate resin

Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate

Reexamination Certificate

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Details

C528S198000

Reexamination Certificate

active

07985823

ABSTRACT:
The invention aims at providing a process for the production of polycarbonate resin which is suppressed in discoloration and reduced in the content of crystalline foreign substance, gel, and so on. The invention relates to a process for the production of polycarbonate resin from raw materials, namely, an aromatic dihydroxyl compound and a carbonic diester through continuous transesterification by the use of a production unit provided with plural reactors, which comprises producing continuously an aromatic polycarbonate resin having a viscosity-average molecular weight of 10,000 to 20,000 for a prescribed time before the termination of the continuous transesterification, discharging the polymerization fluid, cleaning the insides of the reactors with a mixture of the raw materials and then with an aromatic monohydroxy compound, feeding the raw materials and a catalyst to the reactors after the internal temperatures and degrees of vacuum of the reactors have reached respectively to levels falling within −5% to +5% of the levels preset for manufacturing operation, and then initiating manufacturing operation again.

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Korean Office Action issued May 16, 2011, in Korean Patent Application No. 2008-7027537, filed Sep. 25, 2007 (with English-language Translation).

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