Granted Patent
Utility
US 4,904,520 · App. 07/258,913
Gas-permeable, liquid-impermeable nonwoven material
Inventors:
David H. Dumas, Elliott Echt
Patented Case
View Patent ↗
Granted: Feb 27, 1990
Filed: Oct 17, 1988
Inventors
David H. Dumas
Elliott Echt
Assignee (at issue)
HERCULES LLC
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.