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:
Jan. 19, 2010
Filed:
May. 04, 2004
Applicants:
Hans-peter Schal, Dormagen, DE;
Ulrich Wolf, Kerken, DE;
Bernd Thelen, Leverkusen, DE;
Inventors:
Assignee:
Bayer MaterialScience AG, Leverkusen, DE;
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
C07C 249/00 (2006.01);
U.S. Cl.
CPC ...
Abstract
A mixture of isomeric diisocyanatodiphenylmethanes composed of at least 2,2'-diisocyanato-diphenylmethane, 2,4′-diisocyanatodiphenylmethane and 4,4′-diisocyanatodiphenyl-methane is distilled in at least one stage and a divided-wall column is used in at least one distillation stage.