Exxon Corporation (Now Known as Exxonmobil Corporation) and Exxon Chemical Patents, Inc. v. Phillips Petroleum Company, Defendant-Cross

PAULINE NEWMAN, Circuit Judge.

Exxon Mobil Corporation and Exxon Chemical Patents (together “Exxon”) appeal the judgment of invalidity of United States Patent No. 5,324,800 (the '800 patent) on the ground of anticipation. 1 Phillips Petroleum Company has filed a conditional cross appeal on the issue of interference estoppel. We reverse the judgment of invalidity, affirm the ruling on the cross appeal, and remand for further proceedings.

I

In response to Exxon’s suit for infringement of the '800 patent, Phillips asserted, inter alia, the defense of patent invalidity based on anticipation by a…