Process for preparing polycarbonates
US5142018A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 30, 1991 |
| Grant date | Aug 25, 1992 |
| Priority date | — |
| Expiry date | Oct 30, 2011 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G64/307
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A process for preparing polycarbonates according to the invention by melt polycondensation of aromatic dihydroxy compounds and carbonic acid diesters, is characterized by using an aromatic dihydroxy compound and a carbonic acid diester, wherein the combined content of hydrolyzable chlorine in those monomers falls within the particular range. Another process for preparing polycarbonates according to the invention by melt polycondensation of aromatic dihydroxy compounds and carbonic acid diesters, is characterized by using a catalyst comprising (a) a nitrogen containing basic compound and (b) aromatic dihydroxy compound of an alkali metal or alkaline earth metal compound, or (a) and (b) and (c) boric acid or boric ester.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.