Free fall polymerization process for the production of polycarbonates
US5596067A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 1, 1995 |
| Grant date | Jan 21, 1997 |
| Priority date | — |
| Expiry date | Sep 1, 2015 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S159/10
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A method for producing an aromatic polycarbonate comprises introducing to an introduction zone (having a perforated plate) a) a molten monomer mixture of an aromatic dihydroxy compound and a diaryl carbonate, or b) a molten prepolymer obtained by a process comprising reacting an aromatic dihydroxy compound with a diaryl carbonate, and allowing the monomer mixture or prepolymer in the molten state to pass downwardly through the perforated plate and fall freely through a free-fall polymerization reaction zone, thereby effecting polymerization of the monomer mixture or prepolymer during the free-fall thereof. Colorless and high quality aromatic polycarbonates are thus stably produced at a high polymerization rate for a prolonged period of time, using an apparatus which has excellent sealing properties under high vacuum and maintenance of which is easy.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.