Granted Patent
Utility
US 3,956,136 · App. 05/430,452
Nitrogen linked cyclic polyether ion binding polymeric liquid purification materials
Inventor:
Lawrence W. Frost
Patented Case
View Patent ↗
Granted: May 11, 1976
Filed: Jan 3, 1974
Inventor
Lawrence W. Frost
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.