Granted Patent
Utility
US 5,238,590 · App. 07/588,833
Lubricant oil, polyalkylene glycol polycarbonates and process for preparing them
Inventors:
Kinya Mizui, Yoshihisa Kiso, Tetsuo Hayashi, Masahide Tanaka
Patented Case
View Patent ↗
Granted: Aug 24, 1993
Filed: Sep 27, 1990
Inventors
Kinya Mizui
Yoshihisa Kiso
Tetsuo Hayashi
Masahide Tanaka
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.