The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 04, 2005
Filed:
Nov. 08, 2001
Rudolf Kaempf, Haingründau, DE;
Fritz Wilhelm, Karben, DE;
Rudolf Kaempf, Haingründau, DE;
Fritz Wilhelm, Karben, DE;
Zimmer AG, Frankfurt, DE;
Abstract
Polycarbonates are produced by reacting a monomeric carbonate component with at least one diphenol or dialcohol in the presence of a transesterification catalyst, wherein the molten component is mixed with the transesterification catalyst by stirring and a transesterification product is produced, which is polycondensated. For polycondensation, the transesterification product is passed through a preliminary reactor, at least one intermediate reactor and one final reactor, the reactors being connected in series and having a substantially horizontal driven shaft with stirrers attached thereto. It is ensured that in the preliminary reactor and in the final reactor a dwell time of the melt of 5 minutes to 2 hours is maintained, that the temperatures in the preliminary reactor are maintained in the range from 220 to 300° C. and in the final reactor in the range from 240 to 350° C., and that the pressure in the preliminary reactor is maintained in the range from 100 to 800 mbar and in the final reactor in the range from 0.1 to 50 mbar.