by Salim Hasan
A recent Federal Circuit case, Chemours Co. FC, LLC v Daikin Industries, Ltd., Appeal Nos. 2020-1289 and 2020-1290 (Fed. Cir., July 22, 2021), is informative with regard to patent cases involving certain obviousness issues. More specifically, the Chemours case is useful in situations where the prior art “teaches away” from the claimed invention and in circumstances where evidence is presented that the claimed invention cannot be obvious because of its commercial success.
In an inter partes review (IPR), Daiken challenged Chemours’ patent, U.S. Pat. No. 7,126,609. The claims of the ‘609 patent relate to a polymer that has a specific melt flow rate range, i.e., “a high melt flow rate of about 30±3 g/10 min.” The melt flow rate of a polymer indicates how fast the melted polymer can flow under pressure, particularly during extrusion. A higher melt flow rate is beneficial in enhancing the speed at which the polymer can be coated onto a wire.
The PTAB ruled that the claims are obvious over U.S. Pat. No. 6,541,588 (Kaulbach). The Federal Circuit overruled the PTAB, based on the concept of teaching away:
Here the Board appears to have ignored the express disclosure in Kaulbach that teaches away from the claimed invention and relied on teachings from other references that were not concerned with the particular problems Kaulbach sought to solve. In other words, the Board did not adequately grapple with why a skilled artisan would find it obvious to increase Kaulbach’s melt flow rate to the claimed range while retaining its critical “very narrow molecular-weight distribution.”
The Court cited Trivascular, Inc. v. Samuels (a 2016 Federal Circuit case) where the Court found no motivation to modify the prior art where doing so “would destroy the basic objective” of the prior art. As a result, the Court decided that someone skilled in the art would not have a reasonable expectation of success if he or she chose to increase the claimed flow rate.
Furthermore, Chemours submitted evidence of commercial success as an objective indication of non-obviousness. It is fundamental that a nexus between the claimed invention and the commercial success is required. The PTAB had found no nexus, but the Federal Circuit found the PTAB’s reasoning to be circular:
The Board found no nexus between the claimed invention and the alleged commercial success because Kaulbach disclosed all features except for the claimed melt flow rate. The Board then found that other prior art of record disclosed melt flow rates of 50 g/10 min.
Contrary to the Board’s decision, the separate disclosure of individual limitations, where the invention is a unique combination of three interdependent properties, does not negate a nexus. Concluding otherwise would mean that nexus could never exist where the claimed invention is a unique combination of known elements from the prior art.
The Court clarified that a showing of commercial success does not require market share data. Sales figures alone can be sufficient but are not necessarily so. In this case, the Court found the gross sales figures to be adequate.
In addition, the Court addressed the issue of blocking patents as a factor in reducing the weight of commercial success. Daiken had argued that the challenged patent (the ‘609 patent) functioned as a blocking patent. The Court disagreed:
A blocking patent is one that is in place before the claimed invention because “such a blocking patent may deter non-owners and non-licensees from investing the resources needed to make, develop, and market such a later, ‘blocked’ invention.” However, the challenged patent, which covers the claimed invention at issue, cannot act as a blocking patent.
For these reasons, the Chemours case is instructive with respect to obviousness arguments in both prosecution and litigation contexts, particularly in relation to arguments of “teaching away” and commercial success.