PTAB

IPR2020-01660

Dynatemp Intl Inc v. R 421A LLC

Log In
Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Refrigerant with Lubricating Oil for Replacement of R22 Refrigerant
  • Brief Description: The ’179 patent describes refrigerant compositions for replacing R22, a hydrochlorofluorocarbon (HCFC). The core technology is a specific binary mixture known as R421A, consisting of pentafluoroethane (R125) and 1,1,1,2-tetrafluoroethane (R134a) within narrow weight percentage ranges, optionally combined with a lubricating oil.

3. Grounds for Unpatentability

Ground 1: Obviousness and Anticipation over Goble - Claims 1-37 are obvious under 35 U.S.C. §103, and claims 21-37 are anticipated under 35 U.S.C. §102, by Goble.

  • Prior Art Relied Upon: Goble (Patent 6,863,840), with secondary reliance on Singh (Application # 2003/0062508) and Takigawa (Patent 6,207,071) for certain dependent claim limitations.
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Goble teaches replacing ozone-depleting refrigerants like R22 with nonflammable hydrofluorocarbon (HFC) mixtures. To solve this problem, Goble discloses setting the ratio of R125/R134a to establish a pressure-temperature curve approximating R22, which is "roughly 56 weight percent R-125 and 44 weight percent R-134a." Petitioner contended that the term "roughly" brings this disclosure within the claimed ranges of the ’179 patent (57-59% R125 and 41-43% R134a), thereby anticipating or rendering them obvious. Goble also taught the use of compatible lubricating oils, including mineral oil and alkylbenzene, satisfying further limitations.
    • Motivation to Combine (for §103 grounds): Goble provided an explicit motivation to combine R125 and R134a in the disclosed proportions: to create a viable R22 replacement with a similar pressure-temperature performance curve.
    • Expectation of Success (for §103 grounds): A person of ordinary skill in the art (POSITA), starting from Goble’s "roughly 56/44" formulation, would have had a reasonable expectation of success in arriving at the claimed narrow range through routine experimentation to optimize performance.

Ground 2: Obviousness over Singh - Claims 1-37 are obvious over Singh, alone or in view of Goble and Takigawa.

  • Prior Art Relied Upon: Singh (Application # 2003/0062508), with secondary reliance on Goble (’840 patent) and Takigawa (’071 patent).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner asserted that Singh teaches HFC compositions to replace chlorine-containing refrigerants, disclosing concentration ranges that overlap the R421A formulation (e.g., a preferred range of 48-80 parts R125 and 18-60 parts R134a). More specifically, Petitioner pointed to a ternary flammability plot in Singh. It was argued that an arrow on this plot, indicating a direction for optimization, points directly to a formulation that is effectively the 58/42% R125/R134a ratio claimed in the ’179 patent. Singh also taught the use of various lubricants and additives, including mineral oil.
    • Motivation to Combine (for §103 grounds): A POSITA seeking to optimize a non-flammable R22 replacement would be motivated by the diagram in Singh to experiment at or near the formulation indicated by the arrow, which corresponds to the claimed invention.
    • Expectation of Success (for §103 grounds): The explicit graphical guidance in Singh would provide a POSITA with a clear starting point and a high expectation of success in arriving at the claimed R421A formulation through routine experimentation.

  • Additional Grounds: Petitioner asserted additional obviousness challenges based on Powell (Patent 6,606,868), Pearson (Patent 5,688,432), a Federal Register notice (71 Fed. Reg. 56844), Roberts (Patent 6,655,160), and Lemmon (a 2002 technical report). These grounds similarly relied on the argument that the prior art disclosed overlapping or very close compositional ranges, making the claimed invention an obvious optimization.

4. Key Claim Construction Positions

  • Inherent Properties: Petitioner argued that several key claim limitations do not add patentable weight because they are inherent properties of the claimed R125/R134a mixture.
    • The terms "dew point," "bubble point," and "glide" (the difference between dew and bubble points) were asserted to be fixed physical properties of the specific binary refrigerant mixture defined by the claims.
    • Petitioner contended that once the composition "consisting of" R125 and R134a in a specific ratio is defined, its thermodynamic properties are dictated by physical laws (e.g., Raoult's Law) and are not a separate inventive feature.
    • The limitation "phase change" was argued to be an inherent and necessary property of any substance used as a refrigerant in a vapor-compression cycle, and thus lacks patentable weight.

5. Key Technical Contentions (Beyond Claim Construction)

  • No Unexpected Results: A central contention was that the evidence of "unexpected results" submitted during prosecution of the ’179 patent was insufficient to overcome a prima facie case of obviousness.
    • Petitioner analyzed the patentee’s declaration comparing the performance of the claimed 58/42 mixture to a 60/40 mixture from the prior art. Petitioner’s expert, Dr. Groll, concluded that the presented graphs showed a performance difference of less than 1%, which is not a significant or unexpected practical advantage.
    • The petition further argued that the patentee failed to compare the claimed invention to the closest prior art (e.g., Goble’s "roughly 56/44" formulation) and that the performance of R421A was shown to be virtually identical to other known R22 substitutes, undermining any claim of unexpected superiority.

6. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1-37 of Patent 9,982,179 as unpatentable.