CAFC mentions "obvious to try" in Kross case

We likewise reject Kross’s argument that the Board impermissibly employed an “obvious to try” rationale. Kross’s arguments in this regard focus on the Board’s statement that the “reasonable expectation of successfully solving a known problem using known properties of a known material i[s] generally prima facie obvious.” J.A. 6–7. We do not read into this statement the error that Kross complains of. This is not a case, as Kross contends, where “the prior art gave no indication of critical parameters and no direction as to which of many possibilities is likely to be successful.” Appellant’s Br. 24–25 (quoting In re Copaxone Consol. Cases, 906 F.3d 1013, 1025 (Fed. Cir. 2018)). As Kross himself contends, Taylor and Germain identified the parameters that would have been of concern to a skilled artisan (cracking, splitting). Chen teaches that non-gelatin, gel polymers would be beneficial in fixing these critical parameters (high dimensional stability, crack and tear resistance). That is a far cry from impermissibly requiring that a skilled artisan, without any guidance from the prior art, “vary all parameters” until one succeeds. Kubin, 561 F.3d at 1359.