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:
Nov. 15, 1994
Filed:
Jun. 22, 1993
Applicant:
Inventors:
Noritoshi Ishida, Omuta, JP;
Zunzi Tashima, Omuta, JP;
Naoki Sato, Omuta, JP;
Michiya Takasaki, Omuta, JP;
Masaaki Iijima, Omuta, JP;
Kazuyuki Kuroda, Omuta, JP;
Kazunari Nitta, Omuta, JP;
Assignee:
Mitsui Toatsu Chemicals, Incorporated, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C07C / ;
U.S. Cl.
CPC ...
560359 ; 528230 ; 528232 ; 528266 ; 528269 ; 560347 ; 560352 ; 560358 ;
Abstract
The hue of a methylene-crosslinked polyphenylene polyisocyanate continuously produced by the reaction with phosgene in an inert solvent of a polyamine mixture obtained by condensation of aniline and formaldehyde in the presence of an acid catalyst is improved by first removing any residual phosgene followed by heat treatment in the presence of hydrogen chloride gas.