May 21, 2021by Jacob Doughty

Ex parte Ha, is a recent decision of the Patent Trial and Appeal Board (PTAB) addressing the sufficiency of an examiner’s rationale for combining references and the sufficiency of an applicant’s evidence of unexpected results.

In Ex parte Ha, the claim at issue was directed to a thermoplastic resin composition for electronic device housing. The claims required, inter alia, five known components in specific amounts and a specific weight ratio between two of the components – a very typical composition claim. Independent claim 1 is reproduced in part below:

1. A thermoplastic resin composition comprising:

about 100 parts by weight of a polycarbonate resin;

about 1 to about 30 parts by weight of a rubber-modified aromatic vinyl graft copolymer;

about 1 to about 30 parts by weight of a polyester resin;

about 1 to about 20 parts by weight of a glycol-modified polyester resin having about 10 mol% to about 60 mol% of a cyclohexanedimethanol (CHDM) content based on a total amount of a diol component; and

about 0.5 to about 15 parts by weight of a vinyl copolymer comprising an epoxy group,

wherein a weight ratio of the polyester resin to the glycol-modified polyester resin

ranges from about 1:0.1 to about 1:1.

The examiner rejected the claim as obvious, citing a primary reference that disclosed a resin composition having each of the above recited features except for the glycol-modified polyester resin and the claimed weight ratio. For this, the examiner relied on the resin composition in a secondary reference.

Applicant noted that the resin composition of the primary reference was developed to solve the problem of achieving flame retardancy in a rubber-modified aromatic vinyl copolymer resin without using harmful compounds and without deteriorating impact strength. Applicant asserted that the secondary reference did not recognize or address issues relating to the use of flame retardants and, thus, a skilled artisan would not look to the secondary reference to improve the resin compositions of the primary reference.

The PTAB found applicant’s reasoning unpersuasive, noting that the secondary reference employed the claimed glycol-modified polyester resin in a resin composition that solved the different problem of achieving improved dimensional stability, heat resistance, and weld line strength. The PTAB stated that a skilled artisan would have found the improved dimensional stability, heat resistance, and weld line strength achieved in the secondary reference to be desirable attributes in the resin compositions of the primary reference and, thus, would have been led to incorporate the glycol-modified polyester resin.

Perhaps recognizing the challenges of arguing over the examiner’s prima facie case of obviousness, applicant relied heavily on rebuttal evidence of unexpected results. Applicant presented supplemental experimental evidence during prosecution showing that excluding the glycol-modified polyester resin of secondary reference from the claimed resin composition and/or including the glycol-modified polyester resin in amounts outside of claimed weight ratio resulted in inferior impact resistance and processibility.

The examiner did not appear to contest that applicant’s results demonstrated that the claimed composition exhibited an improvement over the primary reference or that such improvement would have been unexpected. Instead, the examiner argued that applicant simply did not provide a sufficient number of inventive examples to demonstrate that the improvement would occur over the entire scope of the claims (noting the generic components and wide ranges of amounts recited in the claims).

Applicant affirmatively argued during the appeal that a “skilled artisan… can clearly and reasonably extrapolate or extend the probative value of the data to other compositions within the scope of the claims.” However, the PTAB found applicant’s argument to be merely conclusory, noting applicant’s burden to provide “an adequate basis to support the conclusion that other embodiments falling within the claim will behave in the same manner… as the exemplary embodiment.”

Takeaways: Demonstrating obviousness in the US can be a bit different than in other jurisdictions. Applicant, in this case, presented arguments akin to the “problem-solution approach” used to argue inventive step in EP practice. However, US examiners and the PTAB often find motivation to combine references far afield from the specific problem addressed by the closest prior art. It is important to bring US obviousness arguments to bear against US obviousness rejections.

Because of the ease with which an examiner can make a prima facie case of obviousness as to composition claims, the patentability of such claims often turns on evidence of unexpected results. The sufficiency of such results often turns on whether the results are “commensurate in scope” with the claims. Arguments of unexpected results should be accompanied with at least a technical explanation – preferably from a skilled artisan – of why results for inventive examples would be expected for all compositions within the scope of a claim.

Judges: Gaudette, Cashion, McGee