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:
Jun. 10, 2003
Filed:
Oct. 13, 2000
Ulrich Penzel, Tettau, DE;
Volker Scharr, Senftenberg, DE;
Dieter Starosta, Schwarzheide, DE;
Hilmar Boesel, Senftenberg, DE;
Eckhard Ströfer, Mannheim, DE;
Joachim Pfeffinger, Ludwigshafen, DE;
Frank Poplow, Overath, DE;
Jürgen Dosch, Ludwigshafen, DE;
Hans Volkmar Schwarz, Waterloo, BE;
Fritz Näumann, Bensheim, DE;
Peter van den Abeel, Kapellen, BE;
Jan Jacobs, Hoogerheide, NL;
Filip Nevejans, St. Pauwels, BE;
Willy van Pee, Brussels, BE;
BASF Aktiengesellschaft, Ludwigshafen, DE;
Abstract
In a process for preparing mixtures of diphenylmethane diisocyanates and polyphenylpolymethylene polyisocyanates having a reduced content of chlorinated by-products and a reduced iodine color number by two-stage reaction of the corresponding mixtures of diphenylmethanediamines and polyphenylpolymethylenepolyamines with phosgene in the presence of at least one inert organic solvent at elevated temperature, separation of the excess phosgene and solvent after the phosgenation is complete and thermal treatment of the reaction product, the mass ratios of phosgene to hydrogen chloride in the residence time apparatus of the second stage of the phosgenation are at the same time 10-30:1 in the liquid phase and 1-10:1 in the gas phase.