Granted Patent
Utility
US 4,973,706 · App. 07/343,459
Process for the preparation of indigo compounds
Inventors:
Yoshihiro Yamamoto, Usaji Takaki, Shinobu Aoki, Isao Hara
Patented Case
View Patent ↗
Granted: Nov 27, 1990
Filed: Apr 25, 1989
Inventors
Yoshihiro Yamamoto
Usaji Takaki
Shinobu Aoki
Isao Hara
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.