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Unexpected Results Should Be Commensurate with the “Full Scope” of the Claims


In Daikin Indus., Ltd v. Chemours Co. FC, LLC, No. 2020-1616, 2021 WL 717017 (Fed. Cir. Feb. 24, 2021), the Federal Circuit panel of Judges Lourie, Wallach, and Chen affirmed a decision of the Patent Trial and Appeal Board (Board), finding claims 1-5 of U.S. Pat. No. 9,574,123 (the ’123 patent) unpatentable as obvious.


Daikin Industries, Ltd (Daikin) owns the ’123 patent, directed to mixtures of hydrofluorocarbons (HFCs), hydrofluoroolefins (HFOs), and one or more of a chlorofluorocarbon (CFC), hydrochlorofluorocarbon (HCFC), chloromethane (HCC), and/or 3,3,3-trifluoropropyne (TFP). Daikin, 2021 WL 717017 at *1. The ’123 patent purports to solve the poor lubrication issue of HFCs and HFOs by adding TFP or one or more chlorine-containing compounds—i.e., CFCs, HCFCs, or HCCs. Id.

Claim 1 of the ’123 patent, the only independent claim at issue, reads:

  1. A composition comprising HFC and HFO, wherein the composition comprises:

1) HFC-32, HFC-125, HFC-134a, and HFC-134 as the HFC;

2) at least one of HFO-1234yf and HFO-1234ze as the HFO;

3) at least one member selected from the group consisting of HCC-40, HCFC-22, HCFC-124, CFC-115, HCFC-1122, CFC-1133, and 3,3,3-triflouropropyne as a third component.

The Board Found the Claims Obvious

The Chemours Company FC, LLC (Chemours) petitioned for inter partes review of all five claims of the ’123 patent. Id. at *2. Chemours challenged the claims as obvious in view of International App. Pub. No. WO 2015/077134 (Van Horn) in combination with U.S. Pat. Pub. No. 2015/0322317 (Collier) in view of a 2014 Air-Conditioning, Heating, and Refrigeration Institute (AHRI) Standard. Id.

There was no material dispute that Van Horn and Collier collectively disclosed all the elements in the challenged claims. Id. at *2. The Board’s obviousness analysis focused on:

(1) whether a skilled artisan would have recognized Collier’s preferred HFO-1234yf embodiment, containing small amounts of HCC-40 and/or CFC-115, as a substitute for the HFO-1234yf in Van Horn’s mixture;

(2) whether a skilled artisan would have been otherwise motivated to combine Collier’s HFO-1234yf with Van Horn’s mixture; and

(3) whether any unexpected increases in lubricity related to the claimed invention should be accorded substantial weight in the obviousness inquiry. Id.

With respect to each question, the Board concluded (1) Yes, (2) Yes, and (3) No. Id. at *3.

The Board noted that both Van Horn and Collier “disclose refrigeration as a primary application for their compositions,” and Collier’s HFO-1234yf was similar or nearly identical in purity to Van Horn’s HFO-1234yf, as taught by the AHRI Standard. Id. Also, the Board found that at the time of the invention it was known that at least some chlorine-containing refrigerants had increased lubricity compared to compounds without chlorine, and that the mechanism by which lubricity was affected was known or suspected. Id. Accordingly, the Board concluded that a skilled artisan would have been motivated to combine Collier’s HFO-1234yf with Van Horn’s mixture to increase lubricity. Id. The Board then rejected Daikin’s nonobviousness argument based on unexpected results because the test results failed to show increased lubricity for the full scope of the claimed inventions. Id.

Accordingly, the Board issued its Final Written Decision finding the challenged claims unpatentable as obvious. Chemours Co. FC, LLC v. Daikin Indus., Ltd., 2020 WL 402064 at *1 (P.T.A.B. Jan. 23, 2020).

Federal Circuit Affirmed the Board’s Decision

Daikin appealed to the Federal Circuit. On appeal, Daikin first argued that the Board violated the Administrative Procedure Act by finding the claims unpatentable based on grounds not advanced in the petition. Daikin, 2021 WL 717017 at *3. The Court disagreed, concluding that the petition properly set forth a substitution theory. Id. Daikin further contested the substantive obviousness analysis of the Board. Id.

Substitution Analysis

The Court disagreed with Daikin that a skilled artisan would have been dissuaded from substituting Collier’s HFO-1234yf for Van Horn’s because of the unpredictability of certain unspecified refrigerant properties, such as deleterious effects on the resulting mixture’s ODP/GWP, safety, reliability, and performance properties. Id. at *4.

The Court pointed out that Daikin itself argued that the proposed substitution would lead to predictable changes in the properties of Van Horn’s mixture. Id. Also, the Court noted that such predictability was supported by expert testimony. Id. The Court held that the Board’s factual determinations underlying its substitution analysis were supported by substantial evidence. Id. at *5.

Unexpected Results

Daikin further argued that, even if the Board did not err in its substitution analysis, the claimed compositions exhibit an unexpected increase in lubricity, and that such unexpected results overcome any evidence of obviousness. Id. The Court disagreed. Id.

But the Court held that any purported unexpected lubricity increase disclosed was not commensurate with the full scope of the claimed invention. Id. In particular, each comparison test disclosed in the ’123 patent involved mixtures comprising only 0.5 mass percent of the third component, but the claims permit the third component to comprise nearly all of the mixture (e.g., claims 1 and 3–5). Id. More importantly, the Court noted “the Board’s findings that lubricity increases from the addition of chlorine-containing compounds were expected,” and that Daikin failed to submit any evidence that the magnitude of any increased lubricity was unexpected. Id.

The Court therefore affirmed the Board’s conclusion, holding that Daikin’s proffered objective indicia of nonobviousness failed to overcome the evidence of obviousness. Id.


This case provides a cautionary tale to practitioners: evidence of unexpected results, used to support nonobviousness, should be commensurate with “the full scope” of the claimed invention to overcome prima facie obviousness. When presenting unexpected results of the claimed invention to overcome a finding of prima facie obviousness, practitioners should carefully consider whether the proffered testing data fairly represent the entire scope of the claims. In addition, if relying on unexpected results, practitioners should take care to explain why such results were unexpected.

This post was written by Stacy Lewis.

© 2021 Finnegan, Henderson, Farabow, Garrett & Dunner, LLPNational Law Review, Volume XI, Number 102



About this Author

Kyu Yun Kim Patent Litigation Attorney Finnegan Law Firm Washington, DC

Kyu Yun Kim focuses on patent litigation and patent prosecution in the chemical and pharmaceutical fields.

Kyu Yun’s litigation experience includes conducting discovery on Abbreviated New Drug Application (ANDA) litigation. She has also researched various legal matters in preparation of inter partes review (IPR) proceedings before the Patent Trial and Appeal Board (PTAB) of the U.S. Patent and Trademark Office.

During law school, Kyu Yun served as an intern with federal judges at three different federal courts, where she gained practical legal skills and insight into the...

Thomas L. Irving Intellectual Property Finnegan, Henderson, Farabow, Garrett & Dunner Washington, DC

Tom Irving has some 45 years of experience in intellectual property law. His U.S. pharma practice includes America Invents Act (AIA) post-grant proceedings, due diligence, counseling, patent prosecution, reissue, and reexamination. In addition to advising on procuring strong U.S. patents, Tom counsels clients on a wide range of mainly pharmaceutical matters, including pre-litigation, Orange Book listings of patents covering FDA-approved drugs, infringement issues, enforceability, supplemental examination, and validity analysis. He has served as lead counsel in numerous patent interferences...

Brooke Wilner Patent Attorney Finnegan

Brooke Wilner, a registered patent attorney, enjoys a varied trial and appellate litigation practice. She practices before U.S. district courts, state courts, the Patent Trial and Appeal Board (PTAB), the U.S. Court of Appeals for the Federal Circuit (CAFC), and the U.S. International Trade Commission (ITC).

Brooke represents both patent owners and accused infringers across a broad range of mechanical and electrical technologies, including clients in the aerospace, automotive, consumer products, software, and hardware industries. She has...