Granted Patent
Utility
US 4,814,124 · App. 07/005,099
Preparation of gas permeable porous film
Inventors:
Mari Aoyama, Michiyasu Ito, Syoichi Tsuji, Toshiyuki Ishii, Tomohide Tanaka
Patented Case
View Patent ↗
Granted: Mar 21, 1989
Filed: Jan 20, 1987
Inventors
Mari Aoyama
Michiyasu Ito
Syoichi Tsuji
Toshiyuki Ishii
Tomohide Tanaka
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.