Granted Patent
Utility
US 5,166,420 · App. 07/784,604
Process for the production of high purity terephthalic acid
Inventors:
Shigemi Shiraki, Kenichi Mizuno
Patented Case
View Patent ↗
Granted: Nov 24, 1992
Filed: Oct 24, 1991
Inventors
Shigemi Shiraki
Kenichi Mizuno
Assignee (at issue)
Mitsui Petrochemical Industries, Ltd.
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.