Granted Patent
Utility
US 4,542,049 · App. 06/645,026
Flexibilized polyurethane pipe coating
Inventors:
Gary A. Tolhurst, Albert L. Haugse
Patented Case
View Patent ↗
Granted: Sep 17, 1985
Filed: Aug 28, 1984
Inventors
Gary A. Tolhurst
Albert L. Haugse
Assignee (at issue)
Ashland Oil, Inc.
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.