Granted Patent
Utility
US 5,869,694 · App. 08/973,162
Process for preparing 4-hydroxy-2-pyrrolidone
Inventors:
Yoshiro Furukawa, Yutaka Shiomi, Kenichi Nagao
Patented Case
View Patent ↗
Granted: Feb 9, 1999
Filed: Nov 19, 1997
Inventors
Yoshiro Furukawa
Yutaka Shiomi
Kenichi Nagao
Assignee (at issue)
DAISO CO., 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.