The U.S. Court of Appeals for the Federal Circuit affirmed a lower court’s ruling of summary judgment of invalidity for failure to disclose the best mode of a patent based on the subjective belief by at least one inventor that the commercial offering was the best mode. Wellman, Inc. v. Eastman Chemical Co., Case No. 10-1249 (Fed. Cir., Apr. 29, 2011) (Rader, J.).

The district court case was initiated by Wellman, which asserted that Eastman Chemical infringed two Wellman patents that disclose polyethylene terephthalate (PET) resins for use in plastic beverage containers. The patents, which claim priority to the same applications and share similar specifications, state that prior art PET resins produced bottles that shrank or grew hazy from crystallization when filled with hot liquids. To overcome these problems, the Wellman patents disclose “slow-crystallizing” PET resins that purportedly retain exceptional clarity by delaying the onset of crystallization.

When Wellman filed the application that lead to the patents, it had a commercial product that had a slow-crystallizing PET resin that solved the above problem. During discovery, one of the inventors testified regarding the formulation of the commercial product. However, the Wellman patents did not disclose the recipe for that product, or any specific recipe for any product, real or hypothetical.

The district court found that at least that one inventor viewed the commercial product as the best mode of practicing the invention at the time of filing and noted that the patent failed to disclose either the formula or trade name of the commercial product. The district court granted Eastman’s motion for summary judgment for failure to disclose the best mode as required by 35 U.S.C. §112, ¶1. Wellman appealed.

Reviewing the lower court’s summary judgment ruling without deference, the Federal Circuit affirmed. The Federal Circuit noted that there was no dispute regarding the first part of the best mode requirement—that is, the parties did not dispute that at least one of the inventors believed that Wellman’s commercial product was the best mode of the claimed invention. Noting the subjective nature of the first element, the court stated that the first part of the test was satisfied regardless of other evidence that might have shown that other embodiments were the best mode. The court determined that it was the subjective belief of the inventor that prevailed in that situation.

In considering the second element of the best mode requirement, whether there is evidence that the applicant concealed the best mode, the Federal Circuit found that disclosure of ingredients that would lead away from the commercial product showed concealment. The Federal Circuit stated that concealment was shown by not only not disclosing the recipe of the commercial product, but also by identifying a preferred concentration range for certain ingredients that would have excluded the ingredients necessary to make the commercial product.

Practice Note: Under pending reform legislation, the best-mode requirement would be eliminated from U.S. patent law. (See IP Update, Vol. 14, No. 3).