Granted Patent
Utility
US 4,190,711 · App. 05/838,017
Thermoplastic polyether polyurethane elastomers
Inventors:
Richard J. Zdrahala, Frank E. Critchfield
Patented Case
View Patent ↗
Granted: Feb 26, 1980
Filed: Sep 29, 1977
Inventors
Richard J. Zdrahala
Frank E. Critchfield
Assignee (at issue)
Union Carbide Corporation
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.