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:
Aug. 08, 1978
Filed:
Mar. 17, 1977
Applicant:
Inventors:
Assignee:
Bayer Aktiengesellschaft, Leverkusen, DE;
Primary Examiner:
Int. Cl.
CPC ...
C08G / ; C08G / ;
U.S. Cl.
CPC ...
526712 ; 528370 ; 528371 ; 528 85 ;
Abstract
The present invention relates to a process for the preparation of polycarbonates which contain aliphatically bound hydroxyl groups by transesterification of aliphatic dihydroxy compounds with glycol carbonate, optionally in the presence of transesterification catalysts, with simultaneous separation of the glycol by fractional distillation, which process is characterized in that ethylene glycol is removed from the reaction mixture as an azeotropic mixture by means of inert solvents with which ethylene glycol is substantially immiscible. The present invention further relates to the preparation of polyurethanes from these polycarbonates.