Process for the preparation of aromatic polycarbonate resins
US5519106A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 17, 1995 |
| Grant date | May 21, 1996 |
| Priority date | — |
| Expiry date | Jan 17, 2015 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G64/307
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A process for preparing an aromatic polycarbonate resin from an aromatic dihydroxy compound and a carbonate diester by transesterification in the presence of a transesterification catalyst comprising; reacting a purified carbonate diester with an aromatic dihydroxy compound in the presence of a transesterification catalyst to form a polycarbonate prepolymer; said carbonate diester containing benzophenone and benzoate ester derivatives having a molecular weight of less than 1,000, each in an amount of 100 ppm or less, said polycarbonate prepolymer having a viscosity average molecular weight of 5,000 to 20,000 at a temperature of 140.degree. to 280.degree. C., the reaction pressure being from 0.1 Torr to normal pressure; polymerizing said prepolymer at a temperature of 240.degree. to 350.degree. C. in a lateral, bi-axial, self-cleaning reactor to obtain an aromatic polycarbonate resin having a viscosity average molecular weight of 15,000 to 60,000. The aromatic polycarbonate is colorless and transparent and is suitable for extrusion molding.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.