That Which Is Unknown Cannot Be Obvious

In Honeywell v. Mexichem, the Federal Circuit found that the PTAB committed legal error during an inter partes reexamination by improperly relying on inherency to find obviousness and in its analysis of motivation to combine references.¹

The claims of the patent owned by Honeywell are directed to a heat transfer composition that is a mixture of the tetrafluoroproene compound, HFO-1234yf (“HFO”), and at least one polyalkylene glycol (“PAG”) lubricant.² During the IPRex, the Board rejected Honeywell’s argument that the claimed combination had unexpectedly favorable properties of stability and miscibility, stating that “the stability and miscibility of HFO-1234yf with a PAG lubricant are ‘inherent properties of an otherwise known refrigerant’ and could not confer patentable weight to the claimed mixture.”³

The Federal Circuit determined that the Board erred in its analysis, stating “that which may be inherent is not necessarily known, and that which is unknown cannot be obvious.”⁴ The Federal Circuit further stated that while all properties of a composition are inherent, unexpected properties may cause a composition to be nonobvious. Thus, the Federal Circuit concluded that the Board committed legal error when dismissing inherent properties without considerations of of unpredictability and unexpectedness.⁵

The Federal Circuit also ruled that the Board erred in dismissing Honeywell’s evidence of unpredictability in the art. The Board stated that one of ordinary skill in the art would “no more have expected failure than success in combining the references.”⁶ The Board concluded that “because there would have been no reasonable expectation of success, one of ordinary skill would have arrived at the claimed combination by mere routine testing.” ⁷ The Federal Circuit stated that the Board improperly placed the burden on Honeywell to establish expectation of failure. The Board admitted that Honeywell’s evidence established overall unpredictability in the art, but then held that such unpredictability would render the invention obvious because it would be achieved by routine testing. The Federal Circuit disagreed, stating that “[u]npredictability of results equates more with nonobviousness rather than obviousness” and that “the patent owner need only establish that the results would have been unexpected to one of ordinary skill at the time of invention.” ⁸

Lastly, the Federal Circuit reminded the Board that “routine experimentation does not necessarily preclude patentability,” ⁹ pointing out that 35 U.S.C. § 103 states: “[p]atentability shall not be negated by the manner in which the invention was made.”¹⁰ Thus, the Federal Circuit ruled that the Board erred in concluding that unpredictability indicates obviousness and in rejecting Honeywell’s objective evidence.