Addressing the sufficiency of the Patent Trial & Appeal Board’s (PTAB) justification of its inter partes review (IPR) determination, the US Court of Appeals for the Federal Circuit reversed the PTAB’s obviousness determinations, concluding that the PTAB’s findings regarding motivation to combine were not supported by substantial evidence. Chemours Company FC, LLC v. Daikin Industries, Ltd., Daikin America, Inc., Case No. 20-1289, -1290 (Fed. Cir., July 21, 2021) (Reyna, J.) (Dyk, J., concurring in part and dissenting in part).

Chemours, owner of the challenged patents, appealed the PTAB’s final written decisions in two IPRs initiated by Daikin. The challenged claims relate to a unique polymer for insulating communication cables formed by pulling wires through melted polymer to coat and insulate the wires, a process known as “extrusion.” The challenged claims of the patents recite that the polymer has a specific melt flow range of about 30+/- g/10 mins. The polymer’s melt flow range correlates with how fast the melted polymer can flow under pressure during extrusion. A higher melt flow rate means a faster coating of the polymer onto a wire. During the IPRs, the PTAB found all challenged claims unpatentable as obvious.

The Federal Circuit reviews the PTAB’s legal determinations de novo and its factual findings for substantial evidence, which “requires more than a ‘mere scintilla’ and must be enough such that a reasonable mind could accept the evidence as adequate to support the conclusion.” Obviousness is a question of law necessarily made on underlying findings of fact, and in making factual findings, the PTAB “must have both an adequate evidentiary basis for its findings and articulate a satisfactory explanation for those findings.”

In this instance, the Federal Circuit found that the PTAB’s obviousness findings were not supported by substantial evidence. According to the Court, while the PTAB may rely on prior art other than the references being applied or combined to inform itself of the state of the art at the time of the invention, the scope of the relevant prior art encompasses only that which is “’reasonably pertinent to the particular problem with which the inventor was involved.”’ Here, the Court explained that the only prior art reference relied on was not appropriate because it expressly taught away from the claimed invention and relied on teachings from other references that were not concerned with the particular problems the prior art sought to solve. As the Court noted, the PTAB “did not adequately grapple with why a skilled artisan would find it obvious to increase [the reference’s] melt flow rate to [the] claimed range while retaining its critical ‘very narrow molecular-weight distribution.’” To support its obviousness conclusion, the PTAB needed “competent proof showing a skilled artisan would have been motivated to, and reasonably expected to be able to, increase the melt flow rate of [the reference’s] polymer to the claimed range when all known methods for doing so would go against [the reference’s] invention by broadening molecular weight distribution.” By failing to provide its reasoning, the PTAB relied on an “inadequate evidentiary basis and failed to articulate a satisfactory explanation that is based on substantial evidence for why a” person of ordinary skill in the art would have been motivated to increase the reference’s melt flow rate to that of the claimed range.

The Federal Circuit also found that the PTAB improperly rejected Chemours’ extensive showing of commercial success—a factor that in obviousness analyses can be linked to “an inventive combination of known elements.” The PTAB erred in applying an element-by-element test for nexus and by rejecting sales data absent market share data.

Lastly, the Court found that the PTAB misapplied the “blocking patents” doctrine, a situation that arises when an earlier-in-time patent prevents practice of a later patent. Here, the Federal Circuit observed that the challenged patent, which claimed the flow rate melt range as the invention, could not be a blocking patent against itself.

In dissent, Judge Timothy Dyk would have found that the primary reference did not teach away from the invention, and accused the majority of “appellate factfinding” without support in the record.