Method for preparing optical-grade polycarbonate compositions
US5502153A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 24, 1994 |
| Grant date | Mar 26, 1996 |
| Priority date | — |
| Expiry date | Oct 24, 2014 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G64/307
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Object: The present invention was conceived in light of the above-described prior art. The object of this invention is to provide a method for preparing optical-grade polycarbonate compositions, which method is able to prepare with good productivity optical-grade polycarbonate compositions that have not only excellent clarity and water resistance, but also excellent retention stability such as heat stability and hue stability when molten and a low content of inclusions and impurities, and that undergo little heat deterioration. Constitution: The method for preparing optical-grade polycarbonate compositions according to this invention, which method comprises the melt-polycondensation of an aromatic dihydroxy compound and a diester carbonate in the presence of a catalyst, followed by the addition of additives B! while the polycarbonate A! obtained as the reaction product is in a molten state, and mixing. In this invention, it is preferable to prepare the optical-grade polycarbonate composition by filtration with a polymer filter following mixing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.