Granted Patent
Utility
US 4,472,328 · App. 06/353,990
Process for producing porous film or sheet
Inventors:
Masaaki Sugimoto, Yukio Watanabe, Kunio Bizen, Tsunemitsu Hasegawa, Masahiro Morita
Patented Case
View Patent ↗
Granted: Sep 18, 1984
Filed: Mar 2, 1982
Inventors
Masaaki Sugimoto
Yukio Watanabe
Kunio Bizen
Tsunemitsu Hasegawa
Masahiro Morita
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.