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:
Feb. 15, 2005
Filed:
Oct. 23, 2000
Wilfried Haese, Odenthal, DE;
Friedrich-karl Bruder, Krefeld, DE;
Thomas Bieringer, Odenthal, DE;
Steffen Kühling, Meerbusch, DE;
Franky Bruynseels, Sint-Gillis-Waas, BE;
Dirk Van Meirvenne, Chonburi, TH;
René DE Cleyn, Wuustwezel, BE;
Wilfried Haese, Odenthal, DE;
Friedrich-Karl Bruder, Krefeld, DE;
Thomas Bieringer, Odenthal, DE;
Steffen Kühling, Meerbusch, DE;
Franky Bruynseels, Sint-Gillis-Waas, BE;
Dirk van Meirvenne, Chonburi, TH;
René de Cleyn, Wuustwezel, BE;
Bayer Aktiengesellschaft, Leverkusen, DE;
Bayer Antwerpen, N.V., Antwerp, BE;
Abstract
A process for the preparation of optical data carriers made of a particualr polycarbonate is disclosed. The polycarbonate is prepared by the phase boundary process that entails reacting at least one dihydroxydiarylalkane in the form of its alkali metal salts with phosgene in the heterogeneous phase in the presence of sodium hydroxide solution and an organic solvent. The process is characterized in that the feedstock have but low content of Fe, Cr, Ni, Zn, Ca, Mg, Al metals or homologues thereof, and in that the organic solvent is separated off, and in that the polycarbonate which is obtained is worked up. The resulting polycarbonate is particularly useful in producing optical data carriers.