Production of thermally stabilized polyester
US4171422A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 11, 1978 |
| Grant date | Oct 16, 1979 |
| Priority date | — |
| Expiry date | Sep 11, 1998 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G63/64
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
High molecular weight linear condensation polyesters are stabilized against deterioration by heat by reacting the polyester in molten form with certain polycarbonates in the presence of a catalytic amount of a phosphonium compound selected from the group consisting of tetra-n-alkylphosphonium acetates and tetra-n-alkylphosphonium halides. For the purpose of this disclosure, polycarbonates are defined as linear polyesters of carbonic acid in which the carbonate groups recur in the polymer chain. In continuous production of the improved polyesters, it is preferred that the polycarbonate and catalyst be added to the process stream with mixing at a point to give 2 to 15 minutes reaction time under superatmospheric pressure before the polyester enters the last polycondensation reactor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.