"Beta crystalline modification of 2,2',2""-nitrilo[triethyl-tris-(3,3',5,5'-tetra-tert-buytl-1,1'-biphenyl- 2,2'-diyl)phosphite]"

Granted: Jul 5, 1994 Filed: Nov 30, 1992

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.