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:
Sep. 20, 1983
Filed:
Jul. 12, 1982
Applicant:
Inventors:
Gerhard Wegener, Wuppertal, DE;
Hartmut Knofel, Odenthal, DE;
Gunther Ellendt, Krefeld, DE;
Marcel Petinaux, Krefeld, DE;
Assignee:
Bayer Aktiengesellschaft, Leverkusen, DE;
Primary Examiner:
Int. Cl.
CPC ...
C07C / ;
U.S. Cl.
CPC ...
2604 / ;
Abstract
Polyisocyanates are prepared by reacting a polyamine solution with a phosgene solution. Excess phosgene and hydrogen chloride formed during the reaction are removed from the reaction mixture. The solvent is subsequently removed from the reaction mixture (e.g., by evaporation and condensation) and treated with a compound containing isocyanate reactive hydrogen atoms to convert any isocyanates present into urethanes and/or ureas. The thus-treated solvent may then be reused, preferably after any urethanes and/or ureas present in the solvent have been removed.