Granted Patent
Utility
US 4,877,900 · App. 07/177,951
Process for preparing terephthalic acid of high quality
Inventors:
Akio Tamaru, Yoshiaki Izumisawa
Patented Case
View Patent ↗
Granted: Oct 31, 1989
Filed: Apr 5, 1988
Inventors
Akio Tamaru
Yoshiaki Izumisawa
Assignee (at issue)
Mitsubishi Chemical 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.