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:
Mar. 02, 1993
Filed:
Oct. 10, 1991
Applicant:
Inventors:
Steffen Kuhlig, Krefeld, DE;
Ralf Pakull, Cologne, DE;
Ulrich Grigo, Kempen, DE;
Peter Tacke, Krefeld, DE;
Dieter Freitag, Krefeld, DE;
Wolfgang Alewelt, Krefeld, DE;
Assignee:
Bayer Aktiengesellschaft, Leverkusen Bayerwerk, DE;
Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C08G / ; C08G / ; C08G / ;
U.S. Cl.
CPC ...
524125 ; 524141 ; 528125 ; 528126 ; 528128 ; 528173 ; 528176 ;
Abstract
A three-step process for the production of solventless polycarbonate is disclosed. Accordingly, a mixture of two different oligocarbonates each prepared by the interfacial method, is prepared in the first process step. In a second step, the mixture is crystallized. The third step entails polycondensation. In an additional embodiment of the invention the first step uses a mixture of one oligocarbonate with a suitable monomer.