Granted Patent
Utility
US 6,458,971 · App. 09/577,157
Process for the production of maleic anhydride
Inventors:
Yoshiaki Iizuka, Tatsuya Ihara, Yasuyuki Yamauchi, Mamoru Sawano, Itaru Sawaki
Patented Case
View Patent ↗
Granted: Oct 1, 2002
Filed: May 24, 2000
Inventors
Yoshiaki Iizuka
Tatsuya Ihara
Yasuyuki Yamauchi
Mamoru Sawano
Itaru Sawaki
Assignee (at issue)
MITSUBISHI CHEMICAL CORPORATION
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.