Patent · US Expired

Two-stage process for the manufacture of thermoplastic polycarbonate

US5652313A · kind A · utility

9Cited by

4References

4Claims

0Family size

Assignee

BAYER HEALTHCARE LLC · DE

Inventors

Steffen Kuhling · Meerbusch, DE
Uwe Hucks · Alpen, DE
Gottfried Zaby · Leverkusen, DE
Claus Wulff · Krefeld, DE

Key dates

Filing date	Jan 31, 1996
Grant date	Jul 29, 1997
Priority date	—
Expiry date	Jan 31, 2016

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC08G64/307
WIPO fieldMacromolecular chemistry, polymers
WIPO sectorChemistry

Abstract

The present invention provides a two-stage melt process for the manufacture of thermoplastic, solvent-free, low-branched polycarbonates with low OH end-group contents with the use of ammonium or phophonium catalysts in the first stage and alkali and alkaline earth catalysts in the second stage.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.