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:
May. 28, 2002
Filed:
Jun. 20, 2001
Steffen Kühling, Meerbusch, DE;
Rolf Lanze, Krefeld, DE;
Michael Prein, Brasschaat, BE;
Rainer Neumann, Krefeld, DE;
Hermann Kauth, Krefeld, DE;
Christian Kords, Krefeld, DE;
Frieder Heydenreich, Düsseldorf, DE;
Tony van Osselaer, Krefeld, DE;
Wilfried Haese, Odenthal, DE;
Bayer Aktiengesellschaft, Leverkusen, DE;
Abstract
A process for the preparation of polycarbonate resins having a low yellowness index is described. The process involves converting phosgene with a sodium bisphenolate solution by means of a phase interface process performed with the exclusion of oxygen. The sodium bisphenolate solution used in the process has a dissolved oxygen content of <150 ppb. Also described are optical data storage media prepared from the polycarbonate of the present invention.