Process for preparing polycarbonate and apparatus for preparing polycarbonate
US6620902B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 8, 2002 |
| Grant date | Sep 16, 2003 |
| Priority date | — |
| Expiry date | Apr 8, 2022 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G64/42
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A process for preparing an end-capped polycarbonate comprises melt reacting an aromatic dihydroxy compound, a carbonic acid diester, and optionally a catalyst in a prepolymerization vessel to form a polycarbonate product; transferring the polycarbonate product from the prepolymerization vessel; mixing the polycarbonate product with an end-capping agent under hermetic seal at a pressure of at least about 760 mm Hg; and transferring the polycarbonate product and end-capping agent mixture to a postpolymerization vessel to endcap the polycarbonate product. An apparatus for preparing an end-capped polycarbonate comprises a prepolymerization vessel having and inlet and an outlet; a postpolymerization vessel having an inlet and an outlet; a mixer in fluid communication with the outlet of the prepolymerization vessel and the inlet of the postpolymerization vessel; and a charging port through which an end-capping agent is charged to the mixer, wherein the mixer is hermetically sealed at greater than or equal to 760 mm Hg.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.