Granted Patent
Utility
US 4,444,640 · App. 06/362,865
Dimensionally stable asbestos-polytetrafluoroethylene diaphragms for chloralkali electrolytic cells
Inventors:
Shan-Pu Tsai, Leo L. Benezra, Lewis R. Horvat, John P. Hazzard
Patented Case
View Patent ↗
Granted: Apr 24, 1984
Filed: Mar 29, 1982
Inventors
Shan-Pu Tsai
Leo L. Benezra
Lewis R. Horvat
John P. Hazzard
Assignee (at issue)
Diamond Shamrock 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.