Granted Patent
Utility
US 4,869,938 · App. 06/899,491
Polypropylene sheet for press-through packages, production process thereof, and polypropylene resin composition
Inventors:
Katsuyuki Usami, Toru Ueki, Hajime Sentoku, Takashi Takahashi, Kazuharu Kanezaki
Patented Case
View Patent ↗
Granted: Sep 26, 1989
Filed: Aug 22, 1986
Inventors
Katsuyuki Usami
Toru Ueki
Hajime Sentoku
Takashi Takahashi
Kazuharu Kanezaki
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.