Granted Patent
Utility
US 4,798,749 · App. 07/184,926
Isopentane as blowing agent to improve coffee retention in foam cups molded from expandable polystrene
Inventors:
Paul E. Arch, Edwin H. Niemann
Patented Case
View Patent ↗
Granted: Jan 17, 1989
Filed: Apr 25, 1988
Inventors
Paul E. Arch
Edwin H. Niemann
Assignee (at issue)
Arco Chemical Company
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.