Stabilization of polymeric organic materials by using synergistic mixtures comprising sterically hindered cyclic amines and derivatives of 3-pyrazolidinone or 1,2,4-triazolidine-3,5-dione

Granted: Oct 10, 1995 Filed: Mar 28, 1994

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.