In Honeywell v. Mexichem (August 2017), a panel of the Federal Circuit reversed the PTAB’s findings of obviousness from an inter partes reexamination.  Honeywell’s patent covered a refrigeration composition for air conditioning systems, including an unsaturated hydrofluorocarbon (HFC) refrigerant plus a polyalkylene glycol (PAG) lubricant.  The primary reference teaches the specific composition of HFC claimed by Honeywell, but only generally referred to immiscible lubricants common in the art, and not PAG lubricants.  The secondary references teach the use of PAG lubricants with saturated HFC refrigerants.  Honeywell’s evidence showed that unsaturated HFC refrigerants are reactive and unstable, and also that PAG lubricants are unstable.

Therefore, one having ordinary skill would not combine them.  In fact, the combination of an unsaturated HFC refrigerant and a PAG lubricant produces the unexpected property of a stable and miscible refrigeration composition.  However, the examiner and the PTAB held that the stability and miscibility properties were inherent to the known refrigerant, unsaturated HFC, and thus could not confer patentable weight to the claimed composition.  The PTAB also stated that one of ordinary skill in the art would no more have expected failure with respect to the stability of combining unsaturated HFC with PAG than would have expected success.  With this “no prediction” determination by the PTAB, one having ordinary skill would only need routine testing to discover the claimed composition.  The Federal Circuit vacated, holding that the PTAB improperly shifted the burden to Honeywell to show that one having ordinary skill would have expected failure.

The proper standard is whether one having ordinary skill would have a reasonable expectation of success.  The Federal Circuit also reminded the PTAB that what is important regarding properties that may be inherent, but unknown, is whether they are unexpected.  Finally, the Federal Circuit reminded the PTAB that section 103 provides that “[p]atentability shall not be negated by the manner in which the invention was made” and thus routine experimentation does not necessarily preclude patentability.