Granted Patent
Utility
US 4,725,338 · App. 06/832,412
Purification process of polymerization solvent
Inventors:
Tadashi Asanuma, Tatuo Ohoka, Minoru Hino, Nobutaka Uchikawa
Patented Case
View Patent ↗
Granted: Feb 16, 1988
Filed: Feb 24, 1986
Inventors
Tadashi Asanuma
Tatuo Ohoka
Minoru Hino
Nobutaka Uchikawa
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.