Granted Patent
Utility
US 5,179,227 · App. 07/779,733
Fractionation process of reaction mixture containing methylene bridged polyphenylene polyisocyanate
Inventors:
Noritoshi Ishida, Zunzi Tashima, Mitsunori Shimamatsu, Kazunari Nitta, Takashi Nagou
Patented Case
View Patent ↗
Granted: Jan 12, 1993
Filed: Oct 23, 1991
Inventors
Noritoshi Ishida
Zunzi Tashima
Mitsunori Shimamatsu
Kazunari Nitta
Takashi Nagou
Assignee (at issue)
Mitsui Toatsu Chemicals, Incorporated
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.