Process for the production of branched melt polycarbonate by late addition of fries-inducing catalyst
US6504002B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 21, 2001 |
| Grant date | Jan 7, 2003 |
| Priority date | — |
| Expiry date | Dec 21, 2021 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G64/307
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
The invention relates to a method for the production of a branched polycarbonate composition, having increased melt strength, by late addition of branch-inducing catalysts to the polycarbonate oligomer in a melt polycondensation process. Surprisingly, it has been found that by adding branch-inducing catalysts, such as alkali metal compounds and/ or alkaline earth metal compounds, to the melt polycarbonate oligomer at a later stage of the melt polycondensation process, preferably after the oligomer has reached an average molecular weight of between about 3,000 and 30,000 g/mole, a unique branched polycarbonate composition is formed that has improved properties. It is believed that the addition of the branch-inducing catalysts at the later stages of the process produces a branched polycarbonate composition having longer chains between the branching points, and thus a new composition is produced. The invention also relates to various applications of the branched polycarbonate composition.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.