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Union Carbide and Shell Oil Go Back to District Court

September 20, 2002
Puknys, Erik R.

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Last Month at the Federal Circuit - October 2002

Judges: Prost (author), Mayer, and Dyk

In Union Carbide Chemical & Plastics Technology Corp. v. Shell Oil Co., No. 02-1001 (Fed. Cir. Sept. 20, 2002), the Federal Circuit affirmed-in-part and reversed-in-part the judgment of the U.S. District Court for the District of Delaware and remanded the case for further proceedings.

Union Carbide Chemical & Plastics Technology Corporation and Union Carbide Corporation (collectively “Union Carbide”) asserted three patents against Shell Oil Company and two subsidiaries (collectively “Shell”). The patents relate to silveroxide catalysts used in the production of ethylene oxide. One patent, referred to as the “synergy patent,” claimed a process of continuously producing ethylene oxide with a catalyst made from a combination of silver, cesium, and lithium “characterizable by an efficiency equation” that was recited in the claim. The other two patents, the “salt patents,” claimed a silver catalyst containing “an efficiency-enhancing amount . . . of a mixture of [salts].”

A jury found that all three patents were not infringed and that the asserted claims were invalid for several reasons. Specifically, the jury determined: (1) that the synergy patent was invalid as indefinite, obvious, and lacking enablement; and (2) that the salt patents were invalid for lack of enablement, anticipation, priority of invention, and obviousness. The district court refused to set aside the jury’s verdicts of noninfringement. It did, how ever, reject the jury’s prior art-based invalidity verdicts as not supported by sufficient evidence and granted Union Carbide’s motion for a new trial for the remaining invalidity issues. Instead of ordering a new trial, however, the district court entered judgment for Union Carbide on those remaining issues.

The Federal Circuit began its review with the synergy patent. The district court had construed the phrase “characterizable by an efficiency equation” to mean that an accused infringer would actually have to use the recited equation to determine the ratios for the various ingredients during catalyst production. The district court recognized that this construction, i.e., interpreting “characterize” to mean “determine,” was contrary to the ordinary meaning of that term, but justified its departure based on certain arguments that Union Carbide had made to the PTO during prosecution. For example, when Union Carbide added the efficiency equation to the claim, it argued that it is was a simple matter to determine the combinations of cesium and alkali metal to provide the synergistic effects claimed.

Citing these remarks, the district court concluded that the claims at issue are product-by-process claims directed to synergistic catalysts with relative amounts of alkali metals that were determined from the efficiency equation. The district court, therefore, instructed the jury that the word “characterize” is to be used interchangeably with the word “determine.”

The Federal Circuit rejected that construction. Specifically, the Federal Circuit disagreed with the district court’s conclusion that Union Carbide disclaimed the ordinary meaning of “characterizable by an efficiency equation” when it added the equation to the claims. According to the Federal Circuit, Union Carbide’s remarks accompanying the amendment adding the efficiency equation to the claims were intended to limit the claimed catalysts to those that are characterized by the equation, and those remarks should not have been interpreted as an attempt to rewrite the claims in product-byprocess format.

Because the district court had erroneously interpreted the synergy patent claims, the Federal Circuit vacated both its infringement and validity judgments and remanded the issues relating to the synergy patent for further proceedings.

But, the Federal Circuit affirmed the district court’s interpretation of the salt patents. Specifically, the Federal Circuit agreed with the district court that the salt patents claim a silver-oxide catalyst whose efficiency is attributable to a particular mixture of salts. Union Carbide had objected to that definition and argued that the claims should simply be read to cover any efficient catalyst having the salts, and that it should not be required to prove the effect of the salts on the overall efficiency of the catalyst.

Again relying on the ordinary meaning of the terms in question, the Federal Circuit interpreted the claim to require that the salts themselves be efficiency enhancing. Dismissing Union Carbide’s arguments that the uncertain nature of chemical reactions makes it difficult, if not impossible, to measure the efficiencies of the salts themselves, the Federal Circuit observed that Union Carbide had submitted just that kind of evidence at trial. Besides, concluded the Court, the inventor of the salt patents chose to claim the inventions using the efficiency-enhancing limitation. As the patent assignee, Union Carbide must live with the legal consequences of that choice, the Court concluded.

Because the district court had correctly construed the salt patent’s claims, the Federal Circuit affirmed the district court’s rulings of no infringement and no anticipation. The Federal Circuit also affirmed the district court’s decision to grant Union Carbide’s motion for a new trial on enablement and obviousness concerning the salt patents, but reversed the district court’s entry of judgment in favor of Union Carbide on those issues. The Federal Circuit found that granting Union Carbide’s motion for JMOL after the verdict on those issues was improper because Union Carbide had not moved for JMOL before the case was submitted to the jury.