Granted Patent
Utility
US 4,840,759 · App. 07/255,679
Isopentane as blowing agent to improve coffee retention in foam cups molded from expandable polystyrene
Inventors:
Paul E. Arch, Edwin H. Niemann
Patented Case
View Patent ↗
Granted: Jun 20, 1989
Filed: Oct 11, 1988
Inventors
Paul E. Arch
Edwin H. Niemann
Assignee (at issue)
Arco Chemical Technology, L.P.
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.