Method of manufacturing polycarbonates
US6339138B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 14, 1999 |
| Grant date | Jan 15, 2002 |
| Priority date | — |
| Expiry date | Oct 14, 2019 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G64/307
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
The manufacture of polycarbonates can be accomplished via an ester interchange reaction of a dihydroxy compound and a carbonic acid diester. The method, which can be a single or multi-stage process wherein the total amount of alkali metal compounds and alkaline earth metal compounds contained as impurities is 1×10−7 moles or less per mole of dihydroxy compound used as raw materials, and the catalyst employed is an ammonium and/or phosphonium compound, a compound which decomposes or volatilizes at a temperature of 100 to 300° C., and/or an alkali metal phosphorous containing inorganic salt and/or alkaline earth metal phosphorous-containing inorganic salt.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.