Title:
PRODUCTION OF POLYCARBONATE
Document Type and Number:
Japanese Patent JPH04142329
Kind Code:
A
Abstract:
PURPOSE:To obtain a colorless and transparent high-molecular weight polycarbonate at good efficiency by melting a starting monomer mixture in a preparation tank, polycondensing the monomer mixture in a tank reactor and increasing the viscosity-average molecular weight on a specified twin-screw extruder. CONSTITUTION:A process for producing a polycarbonate by melt-polycondensing a dihydroxyl compound [e.g. 2,2-bis-(4-hydroxyphenyl) propane] with a bisaryl carbonate (e.g. diphenyl carbonate) by transesrterification, wherein the above monomer are molten in a preparation tank (step 1), the molten monomer mixture is polycondensed in a tank reactor to obtain a polycarbonate of a viscosity- average molecular weight of 5000-30000 (step 2), and a polycarbonate of a viscosity-average molecular weight of 12000-60000 is obtained on a paddle-type self-cleaning twin-screw extruder (step 3). According to the above process, a colorless and transparent high-molecular weight polycarbonate can be produced at good efficiency.
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Inventors:
YAMATO TSUTOMU
KUWANA TAKAAKI
KUWANA TAKAAKI
Application Number:
JP26582890A
Publication Date:
May 15, 1992
Filing Date:
October 02, 1990
Export Citation:
Assignee:
DAICEL CHEM
International Classes:
C08G64/30; C08G64/20; C08G64/40; (IPC1-7): C08G64/30; C08G64/40
Attorney, Agent or Firm:
Kaoru Furuya (3 outside)