Background
Chemours Company FC (formerly DuPont Performance Polymers) holds patents on a high-performance fluoropolymer — a specialized plastic used to insulate wires and cables. The patented material has a high melt flow rate that allows it to be extruded rapidly at low temperatures, making it useful for high-speed wire coating applications. The patents cover specific formulations achieving melt flow rates of approximately 30 g/10 min.
Daikin Industries, a competing fluoropolymer manufacturer, filed two inter partes review (IPR) petitions challenging the Chemours patents as obvious over the prior art. The Patent Trial and Appeal Board (PTAB) agreed with Daikin and found the claimed formulations obvious. Chemours appealed, arguing that the PTAB had misapplied the “teaching away” doctrine and improperly rejected its showing of commercial success as a secondary consideration of nonobviousness.
The Court’s Holding
The Federal Circuit reversed the PTAB’s obviousness findings on two independent grounds.
Teaching away: The court found that the PTAB erred in its teaching-away analysis. The prior art reference at issue warned that increasing melt flow rates could lead to certain tradeoffs in material properties — but it did not affirmatively discourage making the claimed formulations. The Federal Circuit clarified that a prior art reference “teaches away” from a claimed invention only when it specifically discourages or disparages that approach, not merely when it describes potential tradeoffs or complications. A reference that notes a “criticality” for one set of properties while remaining silent about others does not necessarily teach away from the claimed combination.
Commercial success: The PTAB rejected Chemours’ evidence of commercial success because it applied an element-by-element nexus test — requiring Chemours to show that each claimed feature independently drove commercial success. The Federal Circuit reversed, reaffirming that nexus is evaluated for the claimed invention as a whole. When a patentee demonstrates that the commercial product embodies the claimed combination of features, there is a presumption that the success is attributable to the patented invention. The PTAB cannot demand that the patentee separately prove each element drove the commercial outcome.
Key Takeaways
- “Teaching away” requires an affirmative statement in the prior art discouraging the claimed approach; mere disclosure of tradeoffs or alternative design considerations does not constitute teaching away.
- Commercial success nexus is evaluated for the claimed invention as a whole, not element by element — once a patentee shows the commercial product embodies the claims, a presumption of nexus arises.
- PTAB obviousness determinations must be supported by “substantial evidence,” and conclusory findings that do not account for relevant secondary considerations or prior art nuances will not survive Federal Circuit review.
- Patentees defending against IPR challenges should develop robust commercial success records, including evidence that the successful product embodies the claimed combination, rather than relying on isolated feature-by-feature arguments.
Why It Matters
Obviousness is the most common ground on which PTAB invalidates patents in IPR proceedings, and secondary considerations like commercial success are some of the most powerful tools patentees have to defend against such challenges. By clarifying the proper analytical frameworks for both “teaching away” and “commercial success,” the Federal Circuit gave patent owners clearer guidance on how to build effective obviousness defenses.
The case is particularly significant in technology-intensive industries where prior art is dense and inventive steps are incremental. The court’s rejection of the element-by-element nexus approach means that patentees do not have to prove each claimed feature is independently commercially significant — they need only show that their commercial product embodies the patented combination. This makes commercial success a more accessible and meaningful defense in IPR proceedings than the PTAB’s stricter approach would have allowed.