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:
Oct. 13, 1981
Filed:
Aug. 15, 1980
Hans J Astheimer, Neuhofen, DE;
Horst Brandtstaedter, Ludwigshafen, DE;
Rainer Ohlinger, Heidelberg, DE;
Willy Van Pee, Ekeren, BE;
Jaak Van Steen, Wuustwezel, BE;
Friedrich Sauer, Obersuelzen, DE;
Rudolf Schmidt, Frankenthal, DE;
Siegfried Krueger, Speyer, DE;
BASF Aktiengesellschaft, Ludwigshafen, DE;
Abstract
A process for the manufacture of 4,4'-diphenylmethane diisocyanate and a mixture of diphenylmethane diisocyanate isomers containing a controllable amount of uretdione and hydrolizable chlorine which comprises feeding crude MDI to an evaporator, condensing a head fraction in two stages in the presence of an inert gas, feeding the first stage condensate to a distillation column, producing a mixture of diphenylmethane diisocyanate isomers as an overhead, producing 4,4'-diphenylmethane diisocyanate as a side draw, and condensing each of the overhead and side draw in two stages in the presence of an inert gas.