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:
Jun. 08, 2004
Filed:
Apr. 05, 2003
Applicant:
Inventors:
Melanie Moethrath, Düsseldorf, DE;
Uwe Hucks, Alpen, DE;
Silke Kratschmer, Krefeld, DE;
Johann Rechner, Kempen, DE;
Assignee:
Bayer Aktiengesellschaft, Leverkusen, DE;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C08G 6/00 ;
U.S. Cl.
CPC ...
C08G 6/00 ;
Abstract
A process for preparing a melt transesterification catalyst is disclosed. The process entails (i) obtaining a phenol adduct of phosphonium phenolatein the form of crystalline solid and (ii) storing the solid phenol adductin a closed container at relative humidity of 30 to 70 % and at temperature of −30 to 50° C. The thus prepared catalyst is suitable in the production of polycarbonate in the melt transesterification process.