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. 24, 1999
Filed:
Nov. 20, 1997
Applicant:
Inventors:
Rick L Adkins, New Martinsville, WV (US);
Clarence D Blue, New Martinsville, WV (US);
Assignee:
Bayer Corporation, Pittsburgh, PA (US);
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
C08G / ;
U.S. Cl.
CPC ...
2521822 ; 560332 ; 564-5 ; 564-6 ; 564334 ;
Abstract
A process for the production of polymethylene polyphenyl polyisocyanates is disclosed. The process comprises phosgenating the corresponding polyamines in solution in an inert organic solvent, removing excess phosgene, and stripping the solvent, the improvement wherein at least 0.00015 percent by weight of hydrazine or hydrazine derivative per 100 percent by weight of polyamine are added to the polyamines at any time prior to the stripping step.