Granted Patent
Utility
US 4,457,983 · App. 06/381,333
Roofing sheet with upper layer of higher melting point than asphalt
Inventors:
Walter E. Maile, David Q. Boone
Patented Case
View Patent ↗
Granted: Jul 3, 1984
Filed: May 24, 1982
Inventors
Walter E. Maile
David Q. Boone
Assignee (at issue)
Northern Fibre Products 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.