Obviousness of a Substitution

Daikin Indus. v. Chemours Co. (Fed. Cir. 2021) (non-precedential)

The PTAB sided with the patent challenger Chemours — finding claims 1-5 of Daikin’s U.S. Patent No. 9,574,123 unpatentable as obvious.  On appeal, the Federal Circuit has affirmed.

The patent here is covers a refrigerant mixture of three compounds that I have labeled A, B, and C.

  • A: hydrofluorocarbons (HFCs);
  • B: hydrofluoroolefins (HFOs) (such as HFO-1234yf); and
  • C: a chlorine-containing hydrocarbon refrigerant (such as chlorofluorocarbon (CFC)).

The HFCs and HFOs apparently have lower global environmental impact, but lack the lubricant-performance of chlorine-containing CFCs.  The invention balances these factors by mixing them all together. The prior art disclosed the combination of A&B and also the combination of B&C, but did not expressly disclose the full three-way combination.

Substitution: In its discussion, the court focused on the obviousness of a substitution because the prior art spoke of two forms HFO-1234yf.  One form that only contains HFOs (B only); and another form that includes small amounts of CFCs (B and C).  The PTAB and FedCir agreed that, in this case it would have been obvious to start with the A&B combination and then substitute the B&C version of HFO-1234yf in place of the B only version found in the primary reference.

The US Supreme Court most recently wrote about obviousness substitutions in KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 416 (2007).   There, the court explained:

[W]hen a patent claims a structure already known in the prior art that is altered by the mere substitution of one element for another known in the field, the combination must do more than yield a predictable result. . . . [W]hen a patent simply arranges old elements with each performing the same function it had been known to perform and yields no more than one would expect from such an arrangement, the combination is obvious.”

KSR. Here, there is no question that all of the elements were known in the art, the but the patentee argued unpredictability of results especially because the proposed substitution disclosed in the prior art also included other contaminants that could impact performance.

On appeal, the Federal Circuit gave deference to the PTAB’s fact finding — and concluded that it was supported by substantial evidence.   In particular, the Board had relied upon expert testimony that the result was predictable and that “trivial
increase [in the contaminants] would not have prevented a [skilled artisan] from making such a substitution.”

Obviousness affirmed.

= = = =

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; and
  3. at least one member selected from the group consisting of HCC-40, HCFC-22, HCFC-124, CFC-115, HCFC-1122, CFC-1113, and 3,3,3-trifluoropropyne as a third component.

23 thoughts on “Obviousness of a Substitution

  1. 3

    Maybe it’s just me, and I fully understand this is a 103 case arising from an IPR, but it seems to closely resemble Funk Brothers. The claim isn’t for a novel compound, but just a mixture of existing compounds where each one, AFAICT, pretty much still does what it would otherwise do standing alone.

    1. 3.1

      If that is so, all the more interesting how hard the obviousness issue is being fought over, internationally. Consider for example what’s happening at the EPO. At least six divisionals (probably more by now), multiple observations on the patentability filed by members of the public during examination of the merits of the application then, following issue, multiple oppositions filed by several parties, still ongoing, with even a first journey up to the Board of Appeal still to come.

      Interesting, I think, is the pragmatic narrow choice the Applicant made, about which countries to pursue into the national phase and then, at EPO issue, beyond the EPO. Who needs a pan-European patent court when you’ve already got the EPO?

      1. 3.1.1

        Well, I’m not completely sure whether it “is so”—others may have reason to disagree.

        And thanks for providing this helpful color on the EPO situation. I would love to know more about why things are so contested at the EPO, and just more background generally on what’s going on between these competitors and with the industry.


          OK, hardreaders. Below is a Link to the EPO file. Look for the tab “All documents” Click on that for a List of everything in the file. You can open and download as pdf to your heart’s content.

          link to register.epo.org

          Why so contested? Perhaps because you get Bang for your Buck. Perhaps because what is on the EPO file can have an influence on what is decided in other jurisdictions.

          Often it’s the tiniest steps forward in any given technology that are the most hotly contested. Perhaps here we have a good illustration of that maxim?



            PS: Given this is a case about refrigerant, if “hotly contested” was a pun, that’s brilliant!


                CAFC was all fired up, so it froze out Daikin’s arguments—which didn’t have a snowball’s chance in hell—and put the claims on ice.

    2. 3.2

      Funk Brother was about a bag of naturally occurring seeds, which is more narrow than a mixture of existing compounds.

  2. 2

    Ah, I genuinely didn’t realize the context was making arguments to the board.

    In case you’re not aware, the PTO recently dropped a fantastic improvement to their PTAB decision search page on the USPTO page. Particularly worth noting is that you can even do proximity searches within the decisions (subject to the decisions having OCRed correctly of course)!

    So out of curiosity I just searched for “101 novelty”~20 (where “A B”~X searches for A within X words of B) limited by 3600 decisions, and the reversals that popped up were mostly citing Diehr and Synopsys for how prior art doesn’t matter to 101. That’s pretty much what I expected. You’re likely better off digging into the specifics of your case and calling it an improvement rather than relying on the lack of prior art.

  3. 1

    OT, but any advice for responding to rejections where the only outstanding rejection is 101?

    Kind of incredible to get these but the 36xx AU is shameless. Basically I have multiple ones where they say we can’t find any art to perform X, but the inventions are “just” using conventional computer components so they fail in Alice step 2.

    Anyone have some board opinions that might help? CAFC?

    1. 1.1

      Most of the 101 rejection comments on this blog have unfortunately spent vastly more time and effort just complaining about it rather than substantively discussing how to effectively deal with its reality. But from your very brief summary of the rejections, “we can’t find any art to perform X” sounded to me like a strange way to say X is not even 112 spec enabled? While “using conventional computer components” sound more clearly like an argument that step 2 of the Alice 101 analysis [more than just an abstraction] is not met? But since the examiner is stuck with the PTO’s 101 guidelines [even thought the courts do not follow it] I assume you need to point to where in the text of those Guidelines have been violated by the rejections?

      1. 1.1.1

        Paul >>“we can’t find any art to perform X” sounded to me like a strange way to say X is not even 112 spec enabled?

        What an insult. No Paul they are “functional” claims as all information processing claims are and they are fully enabled.

        The rejections take the form of the invention is directed to the abstract idea of X, where X is a summary of the invention. And then in step 2 saying that everything else is merely the use of conventional computers. The inventions are actually pretty complex with algorithms to back them up and everything. But in the 36xx AU that doesn’t mean anything. The rejections admit they can’t find anything that performs the functions the inventions perform and they can’t even string together a 103 argument.

        The abstract idea is typically ridiculously long and absurd.


          “The abstract idea is typically ridiculously long and absurd”

          You should just cite the precedent for how any sufficiently narrow abstract idea is no longer a judicial exception. I think it’s You v. Wish (2017).


            Actually, the case is You v. Be Scre wed, in which the Gist/Abstract sword is wielded to ‘define’ the ‘abstract idea’ as the collection of all claim elements, leaving nothing left to provide any “significantly more.”

            Your mileage may vary as none if these terms have actually been defined significantly enough and every term exemplifies the Nose of Wax syndrome.

      2. 1.1.2

        Paul’s complaining about complaining is pretty rich, seeing how he only snipes from the sidelines on Constitutional issues.


          NW, I was mere reacting to what you said the Examiner said, not assuming its veracity, so I fail to see how you assume any insult. I would think that the specific algorithms in your spec should distinguish over those 101 cases where the spec support was only “do it on any computer.

      3. 1.1.3

        Most likely, it is a confusion and conflation between the A and B items (conventional not enough for B, but conventional is to be given weight for A).

    2. 1.2

      If you have room to amend, an interview might be really helpful! This is rather obvious advice, and I mention it not as a slight, but because so many cases drag on without an interview.

      The adoption and interpretation of the Iancu test has been uneven across 36XX, and many examiners have specific things they’re looking for that suggest eligibility at Prong 2. An interview can help you figure out what your examiner is looking for or whether they’re totally intransigent about eligibility for your invention. You can also ask the examiner to use some of their interview prep time to review the specification for material which could overcome 101.

      Of course if you can’t amend much, or if the examiner is totally dead set against allowance, just appeal ASAP for everyone’s sake.

      1. 1.2.1

        Thank you for advice 101.

        But I was really looking for PTAB decisions regarding 101 rejections with no 102/103 rejection. Obviously for an appeal brief.

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