Granted Patent
Utility
US 4,390,683 · App. 06/309,101
Stretched film structure of the poly-1,3-phenylene terephthalate type
Inventors:
Tadao Yatsu, Akira Todo, Toshiki Sotoyama
Patented Case
View Patent ↗
Granted: Jun 28, 1983
Filed: Oct 6, 1981
Inventors
Tadao Yatsu
Akira Todo
Toshiki Sotoyama
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.