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. 03, 2005
Filed:
Aug. 28, 2002
Heinrich Hähnsen, Duisburg, DE;
Uwe Hucks, Alpen, DE;
Silke Kratschmer, Krefeld, DE;
Manfred Schraut, Krefeld, DE;
Heinrich Hähnsen, Duisburg, DE;
Uwe Hucks, Alpen, DE;
Silke Kratschmer, Krefeld, DE;
Manfred Schraut, Krefeld, DE;
Bayer Aktiengesellschaft, Leverkusen, DE;
Abstract
A process for making a high molecular weight (co)polycarbonate resin is disclosed. The process entails (i) obtaining at least one member selected from the group low molecular weight residue (weight average molecular weight 15,000 to 30,000) of aromatic (co)polycarbonate production, waste of (co)polycarbonate production, remainders of (co)polycarbonate production and (co)polycarbonate recyclate (ii) melting the said member in a suitable vessel to obtain a melt and (iii) feeding the melt into a reactor optionally along with at least one bisphenol or oligocarbonate having terminal OH groups and further optionally with a transesterification catalyst, and (iv) subjecting the melt to transesterification reaction at a temperature of 250 to 350° C., at a pressure below 5 mbar and residence time of 0.02-4 hours.