Gs Cleantech Corp. v. Adkins Energy LLC ( 2020 )


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  • Case: 16-2231   Document: 164    Page: 1    Filed: 03/02/2020
    United States Court of Appeals
    for the Federal Circuit
    ______________________
    GS CLEANTECH CORPORATION,
    Plaintiff-Appellant
    v.
    ADKINS ENERGY LLC,
    Defendant-Cross-Appellant
    ______________________
    2016-2231, 2017-1838
    ______________________
    Appeals from the United States District Court for the
    Northern District of Illinois in No. 1:10-cv-04391, Judge
    Larry J. McKinney.
    --------------------------------------------
    GS CLEANTECH CORPORATION, GREENSHIFT
    CORPORATION,
    Plaintiffs-Appellants
    CANTOR COLBURN LLP
    Interested Party
    v.
    BIG RIVER RESOURCES GALVA, LLC, BIG RIVER
    RESOURCES WEST BURLINGTON, LLC,
    LINCOLNLAND AGRI-ENERGY, LLC, IROQUOIS
    BIO-ENERGY COMPANY, LLC, CARDINAL
    ETHANOL, LLC, LINCOLNWAY ENERGY, LLC,
    Case: 16-2231   Document: 164   Page: 2   Filed: 03/02/2020
    2                GS CLEANTECH CORP. v. ADKINS ENERGY LLC
    ICM, INC., BUSHMILLS ETHANOL, INC., AL-CORN
    CLEAN FUEL, LLC, CHIPPEWA VALLEY
    ETHANOL COMPANY, LLP, HEARTLAND CORN
    PRODUCTS, GEA MECHANICAL EQUIPMENTUS,
    INC., AS SUCCESSOR-IN-INTEREST TO GEA
    WESTFALIA SEPARATOR, INC. PURSUANT TO
    THE NOTICE OF MERGER FILED ON 4/28/2011,
    ACE ETHANOL, LLC, BLUE FLINT ETHANOL LLC,
    UNITED WISCONSIN GRAIN PRODUCERS, LLC,
    FLOTTWEG SEPARATION TECHNOLOGY, INC.,
    ADKINS ENERGY LLC, AEMETIS, INC., AEMETIS
    ADVANCED FUELS KEYES, INC., LITTLE SIOUX
    CORN PROCESSORS, LLLP, GUARDIAN ENERGY,
    LLC, WESTERN NEW YORK ENERGY, LLC,
    SOUTHWEST IOWA RENEWABLE ENERGY, LLC,
    PACIFIC ETHANOL MAGIC VALLEY LLC,
    PACIFIC ETHANOL STOCKTON, HOMELAND
    ENERGY SOLUTIONS, LLC, PACIFIC ETHANOL,
    INC., DAVID J. VANDER GRIEND,
    Defendants-Appellees
    ______________________
    2017-1832
    ______________________
    Appeal from the United States District Court for the
    Southern District of Indiana in Nos. 1:10-cv-00180-RLM-
    DML, 1:10-cv-08000-RLM-DML, 1:10-cv-08001-RLM-
    DML, 1:10-cv-08002-RLM-DML, 1:10-cv-08003-RLM-
    DML, 1:10-cv-08004-RLM-DML, 1:10-cv-08005-RLM-
    DML, 1:10-cv-08006-RLM-DML, 1:10-cv-08007-RLM-
    DML, 1:10-cv-08008-RLM-DML, 1:10-cv-08009-RLM-
    DML, 1:10-cv-08010-RLM-DML, 1:10-cv-08011-RLM-
    DML, 1:10-ml-02181-RLM-DML, 1:13-cv-08012-RLM-
    DML, 1:13-cv-08013-RLM-DML, 1:13-cv-08014-RLM-
    DML, 1:13-cv-08015-RLM-DML, 1:13-cv-08016-RLM-
    DML, 1:13-cv-08017-RLM-DML, 1:13-cv-08018-RLM-
    Case: 16-2231   Document: 164     Page: 3   Filed: 03/02/2020
    GS CLEANTECH CORP. v. ADKINS ENERGY LLC                 3
    DML, 1:14-cv-08019-RLM-DML, 1:14-cv-08020-RLM-
    DML, Judge Larry J. McKinney.
    ______________________
    Decided: March 2, 2020
    ______________________
    STEVEN B. POKOTILOW, Stroock & Stroock & Lavan
    LLP, New York, NY, argued for plaintiffs-appellants. Also
    represented by BINNI N. SHAH.
    JOHN M. WEYRAUCH, Dicke, Billig & Czaja, PLLC, Min-
    neapolis, MN, argued for defendants-appellees Big River
    Resources Galva, LLC, Big River Resources West Burling-
    ton, LLC, Lincolnland Agri-Energy, LLC, Cardinal Etha-
    nol, LLC, Lincolnway Energy, LLC, ICM, Inc., Flottweg
    Separation Technology, Inc., Blue Flint Ethanol, LLC, Da-
    vid J. Vander Griend. Defendants-appellees Big River Re-
    sources Galva, LLC, Big River Resources West Burlington,
    LLC, Lincolnland Agri-Energy, LLC, Cardinal Ethanol,
    LLC, ICM, Inc., Flottweg Separation Technology, Inc., Lit-
    tle Sioux Corn Processors, LLLP, Guardian Energy, LLC,
    Western New York Energy, LLC, Southwest Iowa Renew-
    able Energy, LLC, Pacific Ethanol Magic Valley LLC, Da-
    vid J. Vander Griend also represented by PETER R.
    FORREST.
    MICHAEL BUCHANAN, Patterson Belknap Webb & Tyler
    LLP, New York, NY, argued for defendants-appellees ACE
    Ethanol, LLC, Aemetis Advanced Fuels Keyes, Inc.,
    Aemetis, Inc., Al-Corn Clean Fuel, LLC, Big River Re-
    sources Galva, LLC, Big River Resources West Burlington,
    LLC, Blue Flint Ethanol LLC, Bushmills Ethanol, Inc.,
    Cardinal Ethanol, LLC, Chippewa Valley Ethanol Com-
    pany, LLP, Flottweg Separation Technology, Inc., GEA Me-
    chanical Equipment US, Inc., Guardian Energy, LLC,
    Heartland Corn Products, Homeland Energy Solutions,
    LLC, ICM, Inc., Iroquois Bio-Energy Company, LLC,
    Case: 16-2231    Document: 164     Page: 4   Filed: 03/02/2020
    4                  GS CLEANTECH CORP. v. ADKINS ENERGY LLC
    Lincolnland Agri-Energy, LLC, Lincolnway Energy, LLC,
    Little Sioux Corn Processors, LLLP, Pacific Ethanol Magic
    Valley LLC, Pacific Ethanol Stockton, Pacific Ethanol, Inc.,
    Southwest Iowa Renewable Energy, LLC, United Wiscon-
    sin Grain Producers, LLC, David J. Vander Griend, West-
    ern New York Energy, LLC, Adkins Energy LLC.
    KEITH DAVID PARR, Locke Lord LLP, Chicago, IL, for
    defendant-cross-appellant. Also represented by HUGH S.
    BALSAM, WASIM K. BLEIBEL, JAMES THOMAS PETERKA.
    SPIRO BEREVESKOS, Woodard Emhardt Henry Reeves &
    Wagner, LLP, Indianapolis, IN, for defendant-appellee Ir-
    oquois Bio-Energy Company, LLC. Also represented by
    DANIEL JAMES LUEDERS, LISA A. HIDAY.
    GLENN JOHNSON, McKee, Voorhees & Sease, P.L.C.,
    Des Moines, IA, for defendant-appellee Lincolnway En-
    ergy, LLC.
    JOHN DONALD BEST, Michael Best & Friedrich, LLP,
    Madison, WI, for defendants-appellees Bushmills Ethanol,
    Inc., Chippewa Valley Ethanol Company, LLP, Heartland
    Corn Products, United Wisconsin Grain Producers, LLC.
    Also represented by KENNETH M. ALBRIDGE, III, JOHN C.
    SCHELLER.
    MARC ANDRE AL, Stoel Rives LLP, Minneapolis, MN,
    for defendant-appellee Al-Corn Clean Fuel, LLC.
    RUTH RIVARD, Stinson LLP, Minneapolis, MN, for de-
    fendant-appellee Blue Flint Ethanol LLC.
    CAMILLE L. URBAN, Brown, Winick, Graves, Gross, Bas-
    kerville & Schoenebaum, PLC, Des Moines, IA, for defend-
    ants-appellees Aemetis, Inc., Aemetis Advanced Fuels
    Keyes, Inc., Pacific Ethanol Stockton, Homeland Energy
    Case: 16-2231    Document: 164     Page: 5    Filed: 03/02/2020
    GS CLEANTECH CORP. v. ADKINS ENERGY LLC                    5
    Solutions, LLC, Pacific Ethanol, Inc. Also represented by
    MICHAEL A. DEE.
    ______________________
    Before REYNA, WALLACH, and HUGHES, Circuit Judges.
    WALLACH, Circuit Judge.
    The U.S. District Court for the Southern District of In-
    diana (“District Court”) found Appellants GS CleanTech
    Corporation and Greenshift Corporation’s (together,
    “CleanTech”) U.S. Patent Nos. 7,601,858 (“the ’858 pa-
    tent”), 8,008,516 (“the ’516 patent”), 8,008,517 (“the ’517
    patent”), and 8,283,484 (“the ’484 patent”) (together, “the
    Patents-in-Suit”) unenforceable due to inequitable con-
    duct. Corrected Memorandum Opinion & Order after
    Bench Trial, In re: Method of Processing Ethanol Byprod-
    ucts & Related Subsystems (’858) Patent Litig., No. 1:10-
    ml-02181-LJM-DML (S.D. Ind. Sept. 15, 2016), ECF
    No. 1653 (J.A. 236–313) (Opinion and Order); see J.A. 314–
    15 (Judgment).
    CleanTech appeals. We have jurisdiction pursuant to
    28 U.S.C. § 1295(a)(1) (2012). We affirm.
    BACKGROUND
    I. The Patents-in-Suit 1
    The Patents-in-Suit are directed to the recovery of oil
    from a dry mill ethanol plant’s byproduct, called thin stil-
    lage. ’858 patent, Abstract. 2 The Patents-in-Suit disclose
    1   The Patents-in-Suit share a specification. For the
    ease of reference here, we will refer to the ’858 patent’s
    specification.
    2   Stillage treatment relates to the process of treating
    “‘whole stillage[,]’” which is the “waste stream comprised of
    byproducts” that is a result of the dry milling process. ’858
    patent col. 1 ll. 35–41. Dry milling is “a popular method of
    Case: 16-2231     Document: 164      Page: 6    Filed: 03/02/2020
    6                   GS CLEANTECH CORP. v. ADKINS ENERGY LLC
    a method of “successful” “recover[y] [of] the valuable oil
    from th[e] [thin stillage] byproduct,” 
    id. col. 1
    ll. 52–53, by,
    for example, “evaporating the thin stillage to form a con-
    centrate,” 
    id. col. 2
    ll. 23–25, or syrup, and then “separat-
    ing the oil from the concentrate using a disk stack
    centrifuge,” 
    id. col. 2
    ll. 25–27.
    Independent claim 8 of the ’858 patent recites:
    A method of recovering oil from thin stillage, compris-
    ing, in sequence: evaporating the thin stillage to create
    a concentrate having a moisture content of greater
    than 30% by weight and less than about 90% by
    weight; and centrifuging the concentrate to recover oil.
    
    Id. col. 6
    ll. 26–30. 3 Independent claims 1, 10, and 16 in-
    clude a separate post-evaporation heating step. 
    Id. col. 5
     l. 65–col. 6 l. 7 (Independent Claim 1), col. 6 ll. 34–42 (In-
    dependent Claim 10), col. 6 ll. 59–64 (Independent
    Claim 16). All dependent claims recite various combina-
    tions of temperature, pH, or moisture content ranges for
    the syrup or the use of the centrifuge. 
    Id. col. 6
    ll. 8–33,
    43–58. Independent claim 30 of the ’484 patent similarly
    recites a “method of recovering oil from thin stillage[,]” ex-
    cept it is by “mechanically processing the thin stillage con-
    centrate” instead of centrifugation. ’484 patent col. 8
    ll. 29–37.
    producing ethanol . . . [and] is typically practiced using
    corn.” 
    Id. col. 1
    ll. 35–37. Whole stillage, which has com-
    monly been treated as waste, “may be further separated
    into products known as distillers wet grains and ‘thin stil-
    lage.’” 
    Id. col. 1
    ll. 41–43.
    3    Independent claim 8, which is illustrative, broadly
    recites the claimed invention. The remaining claims recite
    additional limitations beyond those recited in independent
    claim 8.
    Case: 16-2231    Document: 164     Page: 7    Filed: 03/02/2020
    GS CLEANTECH CORP. v. ADKINS ENERGY LLC                    7
    Independent claim 1 of the ’516 patent provides the ad-
    ditional step of “evaporating water from the thin stillage to
    form a thin stillage concentrate.” ’516 patent col. 6 ll. 11–
    19. Independent claim 7 includes the additional step of
    “separating distiller wet grains and thin stillage from the
    whole stillage” and using a disk stack centrifuge to sepa-
    rate the “oil from the thin stillage concentrate.” 
    Id. col. 6
     ll. 34–42. Independent claim 1 of the ’517 patent also re-
    cites the creation of the thin stillage concentrate, within a
    broader moisture content range. ’517 patent col. 6 ll. 32–
    37.
    II. Factual History 4
    A. Development of the Ethanol Oil Recovery System
    In 2000, David Cantrell founded Vortex Dehydration
    Technology (“VDT”), J.A. 117, with the purpose of selling
    products and methods of processing factory waste for re-
    sale, J.A. 118. In 2002, David Winsness joined VDT as its
    Chief Technology Officer. J.A. 117. Later in 2002, Messrs.
    Cantrell and Winsness (collectively, “the Inventors”) met
    Greg Barlage, a “market unit manager for equipment
    sales” at the company Alfa Laval AB, which sold animal
    and vegetable oil processing equipment. J.A. 117, 118.
    Mr. Barlage approached the Inventors with the proposal
    that VDT use Alfa Laval oil processing equipment—such
    as evaporators and centrifuges—in its processes. J.A. 119.
    Soon, the Inventors began developing an oil recovery prod-
    uct specifically designed for animal processing waste prod-
    ucts, using centrifuges provided by Alfa Laval. J.A. 119.
    Relevant here, VDT maintained a business relation-
    ship with Agri-Energy LLC (“Agri-Energy”), J.A. 121,
    which operated a dry-mill ethanol plant in Minnesota,
    4   We will rely on the District Court’s factual recita-
    tion where it is uncontested by the parties. Where certain
    facts are disputed, we will refer to the record evidence.
    Case: 16-2231    Document: 164      Page: 8    Filed: 03/02/2020
    8                  GS CLEANTECH CORP. v. ADKINS ENERGY LLC
    J.A. 120. 5    Starting sometime before June 2003,
    Mr. Cantrell shifted his focus from meat and fish byproduct
    processing to the creation of an ethanol oil recovery system
    and hired employees from Alfa Laval and Agri-Energy, as
    well as a marketing team. J.A. 122. In June 2003,
    Mr. Cantrell sent an email to two Agri-Energy employees,
    including one named George Winter, that included infor-
    mation about how VDT’s oil recovery system for processed
    animal waste might be applicable in an ethanol plant, as
    well as an image of an oil recovery system with a centrifuge
    and an operational cost spreadsheet. J.A. 123. Subse-
    quently, Mr. Cantrell informed Mr. Barlage that Agri-En-
    ergy would send Mr. Barlage a sample of its “thin stillage
    5    The District Court discounted testimony provided
    by Mr. Cantrell at the bench trial, determining that
    Mr. Cantrell’s testimony “on any topic [to be] of little cred-
    ible value.” J.A. 242. The District Court noted that
    Mr. Cantrell made “inconsistent statements,” “had some
    difficulty staying focused,” and “was argumentative and
    unclear about facts when questioned by [Appellees’] coun-
    sel.” J.A. 242–43. The District Court stated that this was
    in sharp contrast to Mr. Cantrell’s “fortuitously remem-
    ber[ing] when events took place and recall[ing] the ‘real’
    meaning of documents when questioned by CleanTech’s
    lawyers.” J.A. 243. The District Court concluded that
    “[Mr.] Cantrell’s testimony sounded carefully scripted ra-
    ther than genuine and generally dismissive of the contem-
    poraneous documentary evidence.” J.A. 243. Accordingly,
    the District Court determined that it would “rel[y] primar-
    ily on the documents and testimony from other witnesses
    about the relationship between Agri-Energy and inventors
    during this period[.]” J.A. 243. “[We] give[] great deference
    to the district court’s decisions regarding [the] credibility
    of witnesses.” Ecolochem, Inc. v. S. Cal. Edison Co., 
    227 F.3d 1361
    , 1378–79 (Fed. Cir. 2000) (internal quotation
    marks and citation omitted).
    Case: 16-2231    Document: 164     Page: 9   Filed: 03/02/2020
    GS CLEANTECH CORP. v. ADKINS ENERGY LLC                   9
    and syrup” for oil recovery testing using a centrifuge.
    J.A. 124. 6
    In June 2003, Mr. Barlage performed oil recovery tests
    on the Agri-Energy samples by heating each sample to a
    temperature of 176 ºF and running them through an Alfa
    Laval centrifuge. J.A. 125. The syrup had a pH of “approx-
    imately 4” and a “moisture content between 70% and 80%.”
    J.A. 125. Based on the tests, Mr. Barlage concluded that it
    was easier to divest oil from syrup than from thin stillage.
    J.A. 125. In his report (“June 2003 Report”), Mr. Barlage
    concluded that “[s]omething in the evaporation process al-
    lows for the product to breakdown to a level where the oil
    can be taken out easily[,]” and recommended additional
    testing at a plant. J.A. 110092.
    In early July 2003, Mr. Barlage traveled to Agri-En-
    ergy and tested VDT’s oil recovery system, including a cen-
    trifuge, with Agri-Energy’s ethanol syrup (“July 2003
    Test”). J.A. 128–29. Again, the test included a syrup with
    a pH of around 4, with a moisture content between 70% and
    80%, and the test was conducted at a temperature of
    180 ºF. J.A. 128–29. During the test, the centrifuge sepa-
    rated the oil from the syrup, but the centrifuge repeatedly
    clogged. J.A. 129. Around this time, Mr. Winsness di-
    rected a VDT employee to prepare a drawing of the ethanol
    oil recovery system, J.A. 130–31, which was completed by
    the end of July 2003, J.A. 132; see J.A. 110044 (Ethanol Oil
    Recovery System Diagram). The employee understood that
    the Ethanol Oil Recovery System Diagram “was intended
    to become a sales drawing.” J.A. 17278.
    On August 1, 2003, Mr. Cantrell emailed several Agri-
    Energy employees (“August 2003 Email”) and attached a
    proposal, dated July 31, 2003.         J.A. 132–33; see
    6   Ethanol syrup is concentrated thin stillage.
    J.A. 124.
    Case: 16-2231     Document: 164      Page: 10    Filed: 03/02/2020
    10                  GS CLEANTECH CORP. v. ADKINS ENERGY LLC
    J.A. 110021–22 (“July 2003 Proposal”). The July 2003 Pro-
    posal stated that VDT “would like to offer Agri-Energy a
    No-Risk trial [of the] ‘Oil Recovery System.’” J.A. 110021.
    The proposal stated that “[t]he test module is designed to
    process 18,000 [pounds] per hour of evaporator condensate
    and recovers 16,000 [pounds] of oil per day adding annual
    profits of $312,000 to $530,000 per year.” J.A. 110021 (em-
    phasis omitted). The proposal went on to detail the “No-
    Risk Trial,” which “allow[ed] Agri-Energy [sixty] days to
    operate the unit and confirm its value[,]” at which point
    Agri-Energy could “purchase the system” for $423,000 or
    “return the skid to [VDT] (no questions asked).”
    J.A. 110021 (emphasis omitted). According to the Inven-
    tors, the purpose of the letter was to seek an opportunity to
    run in-plant tests and obtain data on how the test module
    ran. J.A. 31418–19. Agri-Energy understood the July
    2003 Proposal as an offer for purchase. J.A. 248.
    On August 18, 2003, Mr. Cantrell traveled to Agri-En-
    ergy and, the following day, presented his proposal to the
    Agri-Energy Board of Directors. J.A. 135. In the meeting,
    Mr. Cantrell described VDT’s ethanol extraction system as
    “a process where the corn oil is pulled off[,]” and he asserted
    that the system “worked” and that it “would generate ad-
    ditional income[.]” J.A. 135–36. On the same day, Mr.
    Winsness informed VDT shareholders that Mr. Cantrell
    was “meeting with an ethanol plant” and the Inventors “ex-
    pect[ed] to have an order in the near future ($400K).”
    J.A. 136. On August 27, 2003, Mr. Cantrell informed
    VDT’s chairman that “‘we have made an offer to Agri-En-
    ergy.’” J.A. 136. Agri-Energy did not accept the July 2003
    Proposal, and no centrifuge system was installed at Agri-
    Energy’s facility at that time. J.A. 137; see J.A. 70656 (Tes-
    timony by Mr. Cantrell) (stating that Agri-Energy did not
    accept the July 2003 Proposal). In early 2004, Agri-Energy
    and VDT again communicated regarding the installation of
    an oil recovery system, J.A. 137, and in May 2004, a centri-
    fuge was installed in the Agri-Energy plant, J.A. 139.
    Case: 16-2231     Document: 164       Page: 11     Filed: 03/02/2020
    GS CLEANTECH CORP. v. ADKINS ENERGY LLC                       11
    B. Patent Prosecution History
    In February 2004, the Inventors contacted attorney
    Andrew Dorisio about preparing a patent application for,
    inter alia, their method of separating corn oil from concen-
    trated thin stillage using a centrifuge. J.A. 251–52. Spe-
    cifically, the Inventors sought to patent a method whereby
    “[a]n evaporator would be used to concentrate thin stillage”
    to a syrup with “a moisture content between 60% and 85%,”
    and the syrup would then be mechanically processed to
    separate out the oil, using a disk stack centrifuge. J.A. 251.
    The temperature and pH of the thin stillage—150 ºF to
    212 ºF and with a pH range from 3 to 6—would be the
    standard values of thin stillage in an ethanol plant.
    J.A. 251. Mr. Dorisio informed the Inventors about the on-
    sale bar of 35 U.S.C. § 102 (2000), which required that the
    claimed invention not be sold or offered for sale more than
    one year before the application filing date, and inquired if
    such an offer had been made. J.A. 252; see J.A. 111059; see
    also 35 U.S.C. § 102(b) (“A person shall be entitled to a pa-
    tent unless . . . the invention was . . . on sale . . . more than
    one year prior to the date of the application for patent in
    the United States[.]”). 7       Contemporaneous to their
    7   Congress amended 35 U.S.C. § 102 when it passed
    the Leahy-Smith America Invents Act (“AIA”), and AIA
    § 4(e) made those changes applicable to “any patent appli-
    cation that is filed on or after” September 16, 2012. Pub.
    L. No. 112-29, § 4(e), 125 Stat. 284, 297 (2011). Because
    the application that led to the Patents-in-Suit was filed be-
    fore September 16, 2012, pre-AIA § 102 applies. Under
    pre-AIA § 102, a person shall be entitled to a patent unless
    the claimed invention was on sale more than one year be-
    fore the application’s filing date. 35 U.S.C. § 102(b). A pa-
    tent is invalid under the on-sale bar if, before the filing
    date, the invention was both (1) the subject of a commercial
    Case: 16-2231     Document: 164       Page: 12     Filed: 03/02/2020
    12                  GS CLEANTECH CORP. v. ADKINS ENERGY LLC
    discussion with Mr. Dorisio, the Inventors also conducted
    research on the U.S. Patent and Trademark Office’s
    (“USPTO”) website, which included information about pro-
    visional patent applications and the on-sale bar. J.A. 252.
    Subsequently, the Inventors provided Mr. Dorisio with
    test results from June 2003 and described the July 2003
    Tests. J.A. 255. Mr. Dorisio, apparently without being told
    about the July 2003 Proposal or the Ethanol Oil Recovery
    System Diagram, filed U.S. Provisional Patent Application
    No. 60/602,050 (“the ’050 provisional application”) on Au-
    gust 17, 2004, with the USPTO, J.A. 140, 151; see J.A. 900,
    setting the critical date for the on-sale bar at August 17,
    2003, J.A. 164. See Helsinn Healthcare S.A. v. Teva
    Pharm. USA, Inc., 
    855 F.3d 1356
    , 1360 (Fed. Cir. 2017)
    (“The critical date for the on-sale bar is one year earlier[.]”),
    aff’d, 
    139 S. Ct. 628
    (2019). In May 2005, Mr. Dorisio filed
    a non-provisional application, U.S. Patent Application
    No. 11/122,859 (“the ’859 application”). The’859 applica-
    tion included a letter stating that a separate patent appli-
    cation, entitled “Substantially Fat Free Products From
    Whole Stillage Resulting from the Production of Ethanol
    from Oil-Bearing Agricultural Products,” U.S. Patent Ap-
    plication No. 10/619,833 (“Prevost”), “may be found to claim
    the same invention as at least one claim of the instant ap-
    plication.” J.A. 256 (internal quotation marks omitted).
    In July 2005, Mr. Dorisio provided the Inventors with
    a draft clearance opinion, based on his understanding that
    the Inventors had reduced their claimed invention to prac-
    tice in June 2003, and argued that the Inventors could
    swear behind Prevost, which was filed on July 15, 2003.
    J.A. 256; see J.A. 111060–74 (Draft Clearance Opinion); see
    also J.A. 111065 (“Past correspondence indicates [the] ac-
    tual reduction to practice of the [claimed invention] during
    sale or offer for sale and (2) “ready for patenting.” See Pfaff
    v. Wells Elecs., Inc., 
    525 U.S. 55
    , 67 (1998).
    Case: 16-2231    Document: 164      Page: 13     Filed: 03/02/2020
    GS CLEANTECH CORP. v. ADKINS ENERGY LLC                    13
    experiments conducted in early to mid-June 2003. If accu-
    rate, this date of invention precedes the filing date
    of . . . [Prevost] by at least one month[.]”), 18286 (Prevost)
    (providing a filing date of July 15, 2003). In 2006, the In-
    ventors joined CleanTech, J.A. 35686, which acquired
    VDT’s ethanol oil recovery method applications, J.A. 8–10. 8
    In March 2008, Mr. Winsness transferred the prosecu-
    tion of CleanTech’s ethanol oil recovery method applica-
    tions from Mr. Dorisio to the law firm Cantor Colburn LLP
    (“Cantor Colburn”). J.A. 257. An attorney at Cantor Col-
    burn, Peter Hagerty, explained to at least one of the Inven-
    tors the on-sale bar and the Inventors’ obligation of candor
    toward the USPTO. J.A. 54666. In June 2008, a USPTO
    patent examiner rejected the ’859 application, based in
    part on Prevost. J.A. 258. Cantor Colburn amended the
    ’859 application’s claims. J.A. 258. By at least Septem-
    ber 2008, Cantor Colburn was aware of Mr. Barlage’s test-
    ing in June and July 2003. J.A. 111075; see J.A. 111075
    (Mr. Winsness’s Email to Mr. Hagerty) (explaining that the
    “testing we did in June 2003” showed that “a sequence of
    evaporation followed by centrifugation allows for oil recov-
    ery”).
    In May 2009, a potential investor in CleanTech con-
    ducted due diligence and sought information on the com-
    pany’s pending patent applications; specifically, the
    potential investor requested from the Inventors “‘pre-filing
    disclosures of the inventions’” or “‘pre-filing offers for
    sale[,]’” among other information.         J.A. 261; see
    J.A. 111023. The Inventors denied having any such
    8   The ’858 patent issued from the ’859 application,
    J.A. 900, and all the remaining patents of the Patents-in-
    Suit issued from applications that were continuations of
    the ’859 application, J.A. 910, 921, 953. The Patents-in-
    Suit claim effective filing dates of August 17, 2004.
    J.A. 900, 910, 921, 953.
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    14                 GS CLEANTECH CORP. v. ADKINS ENERGY LLC
    information, although, in 2010, “Mr. Cantrell had retained
    a ‘signed version’ of the July 2003 Proposal in his ‘home
    files,’ and ‘an unsigned version was on [Mr.] Winsness’[s]
    computer[.]’” J.A. 262; see J.A. 63882. In June 2009, Can-
    tor Colburn withdrew the pending ’859 application from is-
    sue. J.A. 264; see J.A. 71338.
    On the same day as the withdrawal, Cantor Colburn
    filed a letter with the USPTO in the ’859 application file
    disclosing that “[s]ometime in May 2004, feasibility testing
    of a process and system for recovering oil from thin stillage
    was performed[.]” J.A. 110380. The letter was also filed
    with the USPTO in the prosecution of the ’516, ’517, and
    ’484 patents. J.A. 264–65; see J.A. 110371–78, 110697–99.
    No reference was made to Mr. Barlage’s June and
    July 2003 testing, the June 2003 Report, the Ethanol Oil
    Recovery System Diagram, or the July 2003 Proposal. See
    generally J.A. 110371–74, 110375–78, 110379–81, 110697–
    99. In October 2009, the USPTO issued the ’858 patent.
    J.A. 900.
    C. The Two Cantrell Declarations
    In March 2010, Mr. Winsness provided a signed copy of
    the July 2003 Proposal to Cantor Colburn. J.A. 267; see
    J.A. 63882. 9 Around June 2010, Mr. Hagerty drafted a
    9  At trial, evidence showed that Mr. Winsness pro-
    vided Cantor Colburn with two letters in March 2010: an
    ink-signed original dated July 31, 2003, and an ink signed
    original dated August 19, 2003. J.A. 63882. The two let-
    ters differed from the electronic versions sent by
    Mr. Cantrell to Agri-Energy, such as by presenting a dif-
    ferent letterhead. J.A. 266–67. The parties presented evi-
    dence about when each letter was signed, but the District
    Court “f[ound] the results of the experts’ analyses inconclu-
    sive with respect to the dating” of the two letters. J.A. 267.
    Additionally, the District Court concluded that “[i]f it had
    Case: 16-2231    Document: 164      Page: 15     Filed: 03/02/2020
    GS CLEANTECH CORP. v. ADKINS ENERGY LLC                    15
    two-page Information Disclosure Statement (“IDS”) to be
    submitted to the USPTO, attaching the July 2003 Pro-
    posal. J.A. 110793–95; see J.A. 270. In the IDS, Mr.
    Hagerty claimed that the ’858 patent’s method was “never
    disclosed, carried out, or performed” more than one year
    before the filing date and that the July 2003 Proposal was
    irrelevant. J.A. 110793–95.
    In May and June 2010, Mr. Winsness met with a com-
    pany that stated that it had reason to believe the ’858 pa-
    tent, as well as the other Patents-in-Suit, were invalid due
    to an offer in violation of the on-sale bar. J.A. 268. In late
    June 2010, Mr. Winsness made an “unannounced” trip to
    Agri-Energy and offered to provide Agri-Energy with a roy-
    alty-free license for CleanTech’s ethanol oil recovery sys-
    tem, which Agri-Energy refused. J.A. 146–47. Agri-
    Energy’s maintenance manager testified that he felt that
    Mr. Winsness was offering “a royalty-free license in ex-
    change for admitting the patent was valid.” J.A. 146.
    Mr. Winsness testified that he had offered a royalty-free
    system to Agri-Energy in 2004 and an “early adopter ad-
    vantage” at an unspecified point in time. J.A. 269. Subse-
    quently, in July 2010, Cantor Colburn attorney Michael
    Rye provided Agri-Energy with a letter, asking Agri-En-
    ergy to “confirm” certain facts, including that VDT had not
    provided Agri-Energy with drawings or diagrams “for the
    not questioned [Mr.] Winsness’[s] veracity on other issues,
    the [District] Court could certainly conclude from this that
    [Mr.] Winsness has a propensity to evade the truth.”
    J.A. 266. For the purposes of our analysis, this point is an-
    cillary—albeit concerning regarding the candor of counsel
    and their clients—to the significant fact that Mr. Cantrell
    provided Agri-Energy with a version of the July 2003 Pro-
    posal by email on August 1, 2003, a fact that is now not
    disputed. J.A. 155; see J.A. 110274 (Second Cantrell Dec-
    laration).
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    16                 GS CLEANTECH CORP. v. ADKINS ENERGY LLC
    proposed system in 2003” and that the system proposed to
    Agri-Energy was for testing purposes. J.A. 147; see
    J.A. 110322–23. Agri-Energy refused to verify the asser-
    tions, as it believed most of them to be “untrue.” J.A. 148.
    Soon after, Mr. Cantrell claimed to Cantor Colburn that he
    hand-delivered the July 2003 Proposal to Agri-Energy on
    August 18, 2003, despite the letter bearing a date weeks
    earlier. J.A. 148; see J.A. 70601.
    In November 2010, Cantor Colburn filed a declaration
    executed by Mr. Cantrell with the USPTO for the ’516 and
    ’517 patent applications and attached a copy of the
    July 2003 Proposal. The declaration explained that Mr.
    Cantrell had hand delivered the July 2003 Proposal to
    Agri-Energy on August 18, 2003. J.A. 148; see J.A. 110016–
    19 (First Cantrell Declaration). Cantor Colburn informed
    the USPTO that the July 2003 Proposal did not violate the
    on-sale bar, as it occurred less than a year before the appli-
    cation filing date. J.A. 148. Omitted from the disclosure
    was Mr. Barlage’s Test Report, the Ethanol Oil Recovery
    System Diagram, and Mr. Barlage’s June and July 2003
    testing. See generally J.A. 110016–19. The USPTO issued
    the ’516 and ’517 patents on August 30, 2011. See J.A. 910,
    921.
    In September 2011, Mr. Cantrell was deposed regard-
    ing the infringement lawsuit of the instant case. J.A. 148;
    see J.A. 20185–249. Mr. Cantrell was shown the July 2003
    Proposal emailed to Agri-Energy on August 1, 2003, and
    Mr. Cantrell testified that the email was not authentic.
    J.A. 278; see J.A. 20207–08. Mr. Cantrell later admitted
    that it was “possible” that he sent the August 1 email.
    J.A. 70601. Mr. Hagerty, when deposed in 2011, stated
    that “‘it sent a chill up his spine’” when he learned that the
    letter was sent on August 1, 2003. J.A. 278. The parties,
    however, had stipulated during the March to August 2010
    timeframe that Cantor Colburn was working under the im-
    pression that the July 2003 Proposal was sent on or near
    August 1, 2003. J.A. 278–79. Mr. Hagerty testified that he
    Case: 16-2231    Document: 164     Page: 17    Filed: 03/02/2020
    GS CLEANTECH CORP. v. ADKINS ENERGY LLC                  17
    was unconcerned about the July 2003 Proposal because it
    did not “disclose anything or amount to an offer.” J.A. 279.
    In July 2012, Cantor Colburn withdrew the ’484 patent
    application, which also contained the First Cantrell Decla-
    ration, and filed a second declaration from Mr. Cantrell
    with the USPTO, which stated that Mr. Cantrell had for-
    gotten about sending the August 2003 Email with the
    July 2003 Proposal attached. J.A. 155, see J.A. 110274
    (Second Cantrell Declaration).        Notably, the Second
    Cantrell Declaration did not provide any retractions of the
    false information provided in the First Cantrell Declara-
    tion—that it misstated that the first delivery of the
    July 2003 Proposal was on August 18, 2003—and did not
    explain the significance of the email in the Second Cantrell
    Declaration, which indicated a pre-critical date offer for
    sale. See generally J.A. 110274. In October 2012, the ’484
    patent issued. J.A. 953.
    III. Procedural History
    Starting in 2009 and continuing through 2014, Clean-
    Tech filed lawsuits against the Appellees 10 and Adkins
    10  The Appellees are: Big River Resources Galva,
    LLC; Big River Resources West Burlington, LLC; Lincoln-
    land Agri-Energy, LLC; Iroquois Bio-Energy Company,
    LLC; Cardinal Ethanol, LLC; Lincolnway Energy, LLC;
    ICM, Inc.; Bushmills Ethanol, Inc.; Al-Corn Clean Fuel,
    LLC; Chippewa Valley Ethanol Company, LLP; Heartland
    Corn Products; GEA Mechanical Equipment US, Inc., as
    Successor-in-Interest to GEA Westfalia Separator, Inc.;
    Ace Ethanol, LLC; Blue Flint Ethanol, LLC; United Wis-
    consin Grain Producers, LLC; Flottweg Separation Tech-
    nologies, Inc.; Aemetis, Inc.; Aemetis Advanced Fuels
    Keyes, Inc.; Little Sioux Corn Processors, LLLP; Guardian
    Energy, LLC; Western New York Energy, LLC; Southwest
    Iowa Renewable Energy, LLC; Pacific Ethanol Magic
    Case: 16-2231    Document: 164      Page: 18     Filed: 03/02/2020
    18                 GS CLEANTECH CORP. v. ADKINS ENERGY LLC
    Energy, LLC (“Adkins”) for infringement of the Patents-in-
    Suit and CleanTech’s U.S. Patent No. 8,168,037 (“the ’037
    patent”) in a number of actions that were subsequently
    combined into a multidistrict litigation case. In 2013,
    CleanTech moved for summary judgment. J.A. 1, 4–5. The
    Appellees and Adkins moved for, inter alia, summary judg-
    ment on invalidity. J.A. 3–5. The District Court found
    there was no infringement. J.A. 83, 86–87, 88, 90–91, 96.
    The District Court determined that specified claims in the
    lawsuit were invalid because of the on-sale bar, J.A. 174;
    anticipation, J.A. 181; obviousness, J.A. 192, 217; incorrect
    inventorship, J.A. 202; inadequate written description,
    J.A. 195; lack of enablement, J.A. 197, 219; and indefinite-
    ness, J.A. 205. 11
    Relevant here, the District Court determined that “un-
    disputed contemporaneous evidence supports only one con-
    clusion, the on-sale bar applies and invalidates the
    [Patents-in-Suit] because,” first, “the July [2003] Proposal
    was the culmination of a commercial offer for sale and,”
    second, “the method described in the [Patents-in-Suit] had
    either or both been reduced to practice or/and there was
    sufficient description of the patented method” by the criti-
    cal date to allow for the implementation of the patent.
    J.A. 167. 12 The District Court explained that the July 2003
    Valley LLC; Pacific Ethanol Stockton; Homeland Energy
    Solutions, LLC; Pacific Ethanol, Inc.; and David J. Vander
    Griend.
    11   Notably, the August 2003 Email and the accompa-
    nying July 2003 Proposal were not produced during discov-
    ery in the infringement litigation before the District Court.
    J.A. 134.
    12   The District Court initially determined that the on-
    sale bar did not apply to the ’484 patent, J.A. 174, but later
    clarified its ruling, explaining that independent claim 30 of
    the ’484 patent was invalid under the on-sale bar because
    Case: 16-2231    Document: 164      Page: 19     Filed: 03/02/2020
    GS CLEANTECH CORP. v. ADKINS ENERGY LLC                    19
    Proposal contained the “major elements of a contract for
    the sale of a system that could perform the patented
    method . . . : [namely] all items necessary to recover oil
    and the price.” J.A. 167. The District Court stated that the
    “dealing between the parties” leading up to the July 2003
    Proposal evidences both parties’ understanding that it was
    an offer for sale. J.A. 168. The District Court relied upon
    the communications between VDT and Agri-Energy, as
    VDT had advised Agri-Energy about the system, how it
    would work, what it was comprised of, where it should be
    placed, what it would accomplish, and the cost of operation.
    J.A. 168–69. The District Court concluded that, under the
    Uniform Commercial Code (“UCC”), the signed proposal
    would have constituted a commercial contract. J.A. 169.
    Further, the District Court explained that other evidence
    regarding VDT and Agri-Energy’s contact surrounding the
    July 2003 Proposal corroborated its conclusion. J.A. 169–
    70 (referencing the creation of the Ethanol Oil Recovery
    System Diagram and Mr. Winsness’s announcement to
    shareholders that VDT had made an offer to sell and that
    the sale would lead to other sales). The District Court ex-
    plained that a reasonable jury would not have concluded
    that the July 2003 Proposal was an offer to test its claimed
    invention as the Inventors knew the method could be suc-
    cessfully reduced to practice, J.A. 170–71 (listing evidence),
    and had been reduced to practice, J.A. 172 (citing Mr. Bar-
    lage’s two instances of practicing the method in 2003); see
    J.A. 172–73 (referencing other communications between
    the Inventors, Agri-Energy, and others implicating a re-
    duction to practice). Accordingly, the District Court inval-
    idated all of the claims of the ’859, ’516, and ’517 patents,
    it required the same steps as the claims of the ’859, ’516,
    and ’517 patents that were also invalid, J.A. 234–35.
    Case: 16-2231     Document: 164      Page: 20     Filed: 03/02/2020
    20                  GS CLEANTECH CORP. v. ADKINS ENERGY LLC
    and independent claim 30 of the ’484 patent pursuant to
    the on-sale bar. 13
    Following its summary judgment determinations, the
    District Court held an inequitable conduct bench trial.
    13  In addition to the Patents-in-Suit, the District
    Court addressed the ’037 patent, which was not included in
    the subsequent inequitable conduct bench trial. J.A. 237–
    38. The District Court determined that the ’037 patent was
    obvious over Prevost and the Patents-in-Suit. J.A. 215–16;
    see J.A. 214 (explaining that it was undisputed that the Pa-
    tents-in-Suit served as prior art to the ’037 patent). Spe-
    cifically, the District Court explained that Prevost and the
    Patents-in-Suit teach the oil recovery method for concen-
    trated thin stillage, which is used with evaporators, as is
    disclosed by the ’037 patent. J.A. 215–16. Compare ’858
    patent col. 5 ll. 28–30, with ’037 patent col. 10 ll. 56–67.
    The District Court stated that a person having ordinary
    skill in the art (“PHOSITA”) would have been “familiar
    with the prior art ethanol plant processes,” like Prevost,
    that “includ[e] evaporation of thin stillage to reduce the
    moisture content before mixing it with wet distiller
    grains[.]” J.A. 215. The District Court explained that the
    Patents-in-Suit disclose dryer efficiencies that can be
    achieved from the removal of oil from syrup prior to any
    mixing with wet distiller grains. J.A. 215–16. Compare
    ’858 patent col. 4 ll. 54–56, col. 5 ll. 28–30, with ’037 patent
    col. 10 ll. 61–67. Because Prevost and the Patents-in-Suit
    disclose the drying of syrup after the oil extraction process
    but before it is added back to the dried distiller wet grains,
    we conclude that the District Court properly determined
    that a PHOSITA would have been motivated to lower the
    moisture content of the syrup, as disclosed in the ’037 pa-
    tent. See Regents of Univ. of Cal. v. Broad Inst., Inc., 
    903 F.3d 1286
    , 1291 (Fed. Cir. 2018); see also 35 U.S.C.
    § 103(a).
    Case: 16-2231     Document: 164      Page: 21    Filed: 03/02/2020
    GS CLEANTECH CORP. v. ADKINS ENERGY LLC                     21
    J.A. 237. Following the bench trial, in which the Inventors
    and attorneys from Cantor Colburn testified, the District
    Court concluded that additional evidence at trial supported
    the District Court’s previous determination that the Pa-
    tents-in-Suit were ready for patenting when the Inventors
    provided the July 2003 Proposal to Agri-Energy. J.A. 294.
    The District Court concluded that CleanTech committed
    inequitable conduct through a “complete lack of regard for
    their duty to the [USPTO].” J.A. 261. Moreover, the Dis-
    trict Court determined that “the [I]nventors made a mis-
    take” by “offer[ing] their invention for sale to Agri-Energy”
    in “July/August 2003,” and “[l]ater, they took affirmative
    steps to hide that fact from their lawyers, then, later [from]
    the [US]PTO when they learned that it would prevent
    them from profiting from the [Patents-in-Suit].” J.A. 299.
    The District Court stated that the Inventors “purposefully
    withheld the information about their dealings with Agri-
    Energy[,]” J.A. 263, and that they “acted to deceive the
    [US]PTO about the facts of the discovery process of the in-
    vention[,]” J.A. 261. In discussing the Inventors’ “inten[t]
    to deceive the [US]PTO,” the District Court stated that the
    conclusion was evidenced by the fact that the Inventors “al-
    lowed [Mr.] Hagerty to file the feasibility testing letter dur-
    ing prosecution of the [’]858 patent, but [did] not tell the
    whole story about their 2003 successes and the [July 2003
    Proposal].” J.A. 292. Moreover, “[w]ith respect to the
    [’]516, the [’]517, and the [’]484 patents,” the District Court
    determined that “the [I]nventors allowed [Mr.] Hagerty to
    file a false affidavit notwithstanding their knowledge that
    [Mr.] Barlage had practiced the method in June 2003 and
    they had made an offer to sell the method to Agri-Energy
    in July or early August of 2003.” J.A. 292–93.
    Additionally, the District Court concluded that Cantor
    Colburn either “purpose[fully] eva[ded]” disclosing or failed
    to seek out relevant information and so participated in the
    inequitable conduct, J.A. 264, “cho[o]s[ing] advocacy over
    candor[,]” J.A. 308. The District Court explained that Mr.
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    22                  GS CLEANTECH CORP. v. ADKINS ENERGY LLC
    Hagerty “never asked the [I]nventors key questions about
    their invention or the meaning of contemporaneous docu-
    ments and, after the litigation started, [Mr. Hagerty] relied
    on the litigation team to do all the investigation.” J.A. 296.
    The District Court stated that Cantor Colburn’s focus on
    “pre-critical date documents” “was purposefully and, in
    [the District] Court’s view improperly narrow.” J.A. 300
    (internal quotation marks omitted). The District Court
    also found that “[i]n the face of [Mr.] Cantrell’s poor health,
    [Mr.] Winsness’[s] and Cantor Colburn’s reliance on [Mr.]
    Cantrell’s recollection of the events surrounding the
    [July 2003 Proposal] . . . , as well as their lackluster inves-
    tigation of events is solid evidence of purposeful behavior.”
    J.A. 307. The District Court determined that Cantor Col-
    burn “ignored the red flags [waving] before them[,]” such
    as the fact that Mr. Winsness “threatened Agri-Energy
    with legal action if it did not corroborate his and
    [Mr.] Cantrell’s story[,]” which Cantor Colburn supported
    by sending Agri-Energy a “thinly-veiled threat[.]” J.A. 307,
    308. 14 The District Court concluded that “[t]he only rea-
    sonable inference is that [Cantor Colburn] believed the
    [I]nventors had made an offer and, with the feasibility test-
    ing letter already before the [US]PTO in both
    14 At the bench trial, Mr. Hagerty testified that he
    had learned about the Inventors’ interactions with Agri-
    Energy around September 2008, including, significantly,
    the occurrence of the July 2003 testing. J.A. 263. When
    asked why he failed to provide the potential CleanTech in-
    vestor with that information, Mr. Hagerty “seemed per-
    plexed that [the] request should have covered the 2003
    testing because [Mr.] Hagerty had determined it was irrel-
    evant to patentability.” J.A. 263. We conclude, as the Dis-
    trict Court found, “[t]his conclusion is problematic in light
    of the fact that the written information [Mr.] Hagerty re-
    ceived from [Mr.] Winsness about the 2003 bench test
    stated that it worked[.]” J.A. 263.
    Case: 16-2231    Document: 164      Page: 23    Filed: 03/02/2020
    GS CLEANTECH CORP. v. ADKINS ENERGY LLC                   23
    prosecutions, . . . which implied a later reduction to prac-
    tice date, they chose advocacy over candor.” J.A. 308. The
    District Court held the Patents-in-Suit unenforceable due
    to inequitable conduct. J.A. 313.
    DISCUSSION
    I. Standard of Review and Legal Standard
    “Inequitable conduct is an equitable issue committed to
    the discretion of the trial court and is, therefore, reviewed
    by this court under an abuse of discretion standard.” En-
    ergy Heating, LLC v. Heat On-The-Fly, LLC, 
    889 F.3d 1291
    , 1299 (Fed. Cir. 2018) (citations omitted). We
    leave undisturbed the trial court’s inequitable conduct de-
    cision unless the appellant establishes “that the ruling is
    based upon clearly erroneous findings of fact or a misappli-
    cation or misinterpretation of applicable law or that the
    ruling evidences a clear error of judgment on the part of the
    [trial] court.” Kingsdown Med. Consultants, Ltd. v. Hollis-
    ter Inc., 
    863 F.2d 867
    , 876 (Fed. Cir. 1988) (citation omit-
    ted) (en banc in relevant part).
    To prevail on a claim of inequitable conduct in a patent
    case, the accused infringer must prove by clear and con-
    vincing evidence that the patentee: (1) “knew of the refer-
    ence” or prior commercial sale; (2) “knew that it was
    material”; and (3) “made a deliberate decision to withhold
    it.” See Therasense, Inc. v. Becton, Dickinson & Co., 
    649 F.3d 1276
    , 1290 (Fed. Cir. 2011) (en banc). “Proving that
    the [patentee] knew of a reference, should have known of
    its materiality, and decided not to submit it to the [US]PTO
    does not prove specific intent to deceive.” 
    Id. Instead, “the
      specific intent to deceive must be the single most reasona-
    ble inference able to be drawn from the evidence.” 
    Id. (in- ternal
    quotation marks and citation omitted).
    The inequitable conduct claim here relates to whether
    the patentee failed to disclose information that would have
    implicated the on-sale bar under 35 U.S.C. § 102(b). A
    Case: 16-2231     Document: 164      Page: 24    Filed: 03/02/2020
    24                  GS CLEANTECH CORP. v. ADKINS ENERGY LLC
    patent is invalid under the on-sale bar if, before the critical
    date, the invention was: (1) the subject of a commercial
    sale or offer for sale; and (2) “ready for patenting.” 
    Pfaff, 525 U.S. at 67
    . First, whether the claimed invention was
    the subject of an offer for sale is an inquiry based on “con-
    tract law principles.” Linear Tech. Corp. v. Micrel, Inc., 
    275 F.3d 1040
    , 1048 (Fed. Cir. 2001). “It also involves an as-
    sessment of whether the circumstances surrounding the
    transaction show that the transaction was not primarily for
    purposes of experimentation.” Allen Eng’g Corp. v. Bartell
    Indus., Inc., 
    299 F.3d 1336
    , 1352–53 (Fed. Cir. 2002). “A
    use may be experimental only if it is designed to (1) test
    claimed features of the invention or (2) . . . determine
    whether an invention will work for its intended purpose[.]”
    Clock Spring, L.P. v. Wrapmaster, Inc., 
    560 F.3d 1317
    , 1327
    (Fed. Cir. 2009) (involving a question of public use and not
    the on-sale bar but stating that “[t]hough a prior commer-
    cial sale and not a prior public use was at issue in Allen
    Engineering, the factors explicated are equally relevant to
    an analysis of experimental use”). To determine if a trans-
    action was conducted primarily to experiment, a district
    court may look to the Allen factors to assess the transac-
    tion’s experimental nature. See Allen 
    Eng’g, 299 F.3d at 1352
    –53. These factors include: “(1) the necessity for
    public testing, . . . (3) the nature of the invention,
    [and] . . . (10) whether the invention reasonably requires
    evaluation under actual conditions of use[.]” 
    Id. (citation omitted).
    If a prior commercial sale was primarily for pur-
    poses of experimentation, the sale will not serve as a bar.
    See Clock 
    Spring, 560 F.3d at 1327
    . “In making this pa-
    tentability determination, the [trial] court should apply the
    preponderance of the evidence standard[.]” 
    Therasense, 649 F.3d at 1291
    –92.
    Second, “[a]n invention is ‘ready for patenting’ when
    prior to the critical date: (1) the invention is reduced to
    practice; or (2) the invention is depicted in drawings or de-
    scribed in writings of sufficient nature to enable a
    Case: 16-2231    Document: 164      Page: 25    Filed: 03/02/2020
    GS CLEANTECH CORP. v. ADKINS ENERGY LLC                   25
    [PHOSITA] to practice the invention.” Hamilton Beach
    Brands, Inc. v. Sunbeam Prods., 
    726 F.3d 1370
    , 1375 (Fed.
    Cir. 2013) (citation omitted) (emphases added).
    II. The District Court Did Not Abuse Its Discretion in De-
    termining that the Patents-in-Suit Are Unenforceable
    Due to Inequitable Conduct 15
    After a bench trial, the District Court concluded that
    CleanTech and its attorneys at Cantor Colburn engaged in
    15   Despite CleanTech’s arguments to the contrary, see
    Appellant’s Reply Br. 4, we will address the issue of ineq-
    uitable conduct without first conducting a de novo review
    of the District Court’s summary judgment on-sale bar de-
    termination. A finding of a reference’s or prior sale’s ma-
    teriality is required for an inequitable conduct
    determination, see 
    Therasense, 649 F.3d at 1290
    , which is
    reviewed for abuse of discretion, see Energy 
    Heating, 889 F.3d at 1299
    . CleanTech contends that materiality may
    not be reviewed in the context of the inequitable conduct
    claim, as materiality was not properly raised before and
    addressed by the District Court during the inequitable con-
    duct bench trial. Appellant’s Reply Br. 4–5. This argument
    is jejune. The District Court held an eight-day bench trial
    in which materiality was squarely before it. In addition to
    incorporating the evidence and findings of materiality that
    had been presented at the summary judgment stage,
    J.A. 237, the District Court admitted other relevant evi-
    dence during the trial, including documents relating to the
    June and July 2003 testing, J.A. 40144–45, 40153–54, and
    previously unheard testimony from the Inventors and at-
    torneys with Cantor Colburn, J.A. 294, all relating to the
    materiality of the July 2003 Proposal. Moreover, following
    the bench trial, the District Court determined that “its con-
    clusion [from the Summary Judgment Order] that [the
    July 2003 Proposal] evidence both elements of the on-sale
    bar” was “confirm[ed]” and, after incorporating “by
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    26                  GS CLEANTECH CORP. v. ADKINS ENERGY LLC
    inequitable conduct in obtaining the Patents-in-Suit, ren-
    dering the patents unenforceable. J.A. 313. On appeal,
    CleanTech argues that the District Court made clearly er-
    roneous findings of fact and misapplied the law with re-
    spect to its on-sale bar determination, as well as its
    conclusions regarding the parties’ knowledge of materiality
    and their intent to deceive. Appellant’s Br. 104, 109–10.
    We disagree with CleanTech.
    A. On-Sale Bar
    The District Court “conclude[d] that the undisputed
    contemporaneous evidence supports only one conclusion,
    [that] the on-sale bar applies and invalidates the [Patents-
    in-Suit] because” the claimed invention was the subject of
    an offer for commercial sale and it was ready for patenting.
    J.A. 167. We address each determination in turn.
    1. The District Court Did Not Abuse Its Discretion in De-
    termining the Claimed Invention Was the Subject of a
    Pre-Critical Date Offer for Sale
    The District Court concluded that the July 2003 Pro-
    posal constituted a pre-critical-date offer for sale. J.A. 299.
    reference the findings of fact and conclusions of law in the
    Summary Judgment Order,” the District Court determined
    that “[f]urther evidence at trial only buttresse[d] the [Dis-
    trict] Court’s earlier conclusion, particularly with respect
    to the ready for patenting element of the on-sale bar.” J.A.
    294. Additionally, despite CleanTech’s suggestions to the
    contrary, see Appellant’s Br. 105, inequitable conduct’s ma-
    teriality requirement does not provide the patentee with
    the right to a jury and instead must be resolved by the trial
    court, see Am. Calcar, Inc. v. Am. Honda Motor Co., Inc.,
    
    651 F.3d 1318
    , 1333 (Fed. Cir. 2011) (“Inequitable conduct
    is equitable in nature, with no right to a jury, and the trial
    court has the obligation to resolve the underlying facts of
    materiality and intent.”).
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    GS CLEANTECH CORP. v. ADKINS ENERGY LLC                     27
    CleanTech contends that it was not an offer as it “did not
    in fact perform the method for Agri-Energy, before the crit-
    ical date, for a promise of future compensation.” Appel-
    lant’s Br. 37 (internal quotation marks and emphasis
    omitted) (citing Plumtree Software, Inc. v. Datamize, LLC,
    
    473 F.3d 1152
    , 1162–63 (Fed. Cir. 2006)). We disagree with
    CleanTech.
    The District Court did not abuse its discretion in deter-
    mining that the claimed invention was the subject of an of-
    fer for sale in the summer of 2003. First, relying on the
    UCC, the District Court concluded that the July 2003 Pro-
    posal was a “sale on approval” that was made before the
    critical date. J.A. 169 (citing U.C.C. § 2-326); see U.C.C.
    § 2-326(1)(a) (“[I]f delivered goods may be returned by the
    buyer even though they conform to the contract, the trans-
    action is . . . a ‘sale on approval’ if the goods are delivered
    primarily for use[.]”); see also 
    Linear, 275 F.3d at 1052
    (ex-
    plaining “that the [UCC] should inform the [district court’s]
    analysis of the contractual issues[,]” such as the on-sale
    bar). The July 2003 Proposal provides an offer of “all items
    necessary to recover oil and the price,” J.A. 167, and the
    Inventors understood the offer to Agri-Energy was a “first
    sale” that would lead to additional sales, J.A. 170–72. Ac-
    cordingly, the District Court properly concluded that the
    July 2003 Proposal was an “offer for sale.” 
    Pfaff, 525 U.S. at 67
    .
    CleanTech’s primary counterargument is unavailing.
    CleanTech contends that the District Court misconstrued
    the law by failing to apply Plumtree’s requirement that the
    “challenger must prove that the patentee either: (i) ‘made
    a commercial offer to perform the patented method[]’[;] or
    (ii) ‘in fact performed the patented method for a promise of
    future compensation.’” Appellant’s Br. 36. CleanTech,
    however, did not make this argument before the District
    Court and cited to Plumtree only once in its summary judg-
    ment opposition and only for the proposition that the
    July 2003 Proposal was not invalidating because it “did not
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    28                  GS CLEANTECH CORP. v. ADKINS ENERGY LLC
    unambiguously require use of [CleanTech’s] patented
    methods[.]” J.A. 26364 (citing 
    Plumtree, 473 F.3d at 1163
    ).
    Because we apply the law of the regional circuit as to pro-
    cedural matters, see Info-Hold, Inc. v. Muzak LLC, 
    783 F.3d 1365
    , 1371 (Fed. Cir. 2015), here the Seventh Circuit,
    we will not decide an issue for the first time on appeal, see
    Scheurer v. Fromm Family Foods LLC, 
    863 F.3d 748
    , 755
    (7th Cir. 2017) (“The well-established rule in th[e Seventh]
    Circuit is that a plaintiff waives the right to argue an issue
    on appeal if she fails to raise the issue before a lower court.”
    (internal quotation marks and citation omitted)).
    2. The District Court Did Not Abuse Its Discretion in De-
    termining the Claimed Invention Was Ready for Patent-
    ing Before the Critical Date
    The District Court determined that the claimed inven-
    tion was ready for patenting prior to the critical date.
    J.A. 167. CleanTech contends that the District Court failed
    to find that the claimed invention was reduced to practice
    “on a claim-by-claim basis” for each of the Patents-in-Suit.
    Appellant’s Br. 46. We disagree with CleanTech.
    The District Court did not abuse its discretion in deter-
    mining the claimed invention was ready for patenting in
    June or July 2003. First, with respect to the reduction to
    practice, the District Court relied upon the two tests con-
    ducted by Mr. Barlage in the summer of 2003 to support its
    determination. J.A. 126–27; see Hamilton Beach 
    Brands, 726 F.3d at 1375
    (“An invention is ‘ready for patenting’
    when prior to the critical date: . . . the invention is reduced
    to practice[.]” (emphasis added) (citation omitted)). The
    District Court explained that, in June 2003, Mr. Barlage
    tested an ethanol syrup with a pH, moisture content, and
    temperature within the claimed ranges recited in the Pa-
    tents-in-Suit, compare J.A. 125–26 (describing Mr. Bar-
    lage’s testing, which heated thin stillage to a temperature
    of 176 ºF, with a pH of “approximately 4, and moisture con-
    tent between 70% and 80%”), with J.A. 920 (’516 patent)
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    GS CLEANTECH CORP. v. ADKINS ENERGY LLC                  29
    (Dependent Claim 6) (reciting “[a] method of recovering oil
    from thin stillage” with a temperature between 150 ºF and
    212 ºF, a pH between 3 and 6, and a moisture content of
    greater than 30% and less than 90% by weight), and sepa-
    rated oil from the syrup with a centrifuge, reporting that
    “the oil can be taken out easily,” J.A. 125–26, 171. Indeed,
    the Inventors themselves made statements contemporane-
    ous to the June and July 2003 testing that the claimed in-
    vention was reduced to practice. J.A. 127 (Mr. Cantrell
    stating to Agri-Energy following the July 2003 Test that
    “‘[t]he technology is available to remove the oil, and the
    quick payback from the new revenue stream, make this a
    very viable program’”), 111065 (Mr. Dorisio’s Draft Clear-
    ance Opinion to the Inventors) (“Past correspondence indi-
    cates your actual reduction to practice of the removing oil
    from syrup aspect of the proposed invention during experi-
    ments conducted in early to mid-June 2003.” (emphases
    added)). Moreover, immediately following the July 2003
    Test, Mr. Winsness then directed a VDT employee to pre-
    pare the Ethanol Oil Recovery System Diagram, J.A. 130–
    32; see J.A. 110044 (Ethanol Oil Recovery System Dia-
    gram), which the employee understood “was intended to be-
    come a sales drawing[,]” J.A. 132 (internal quotation marks
    omitted); see J.A. 246 (the VDT employee “understood that
    the drawings would be used for sales purposes by [Mr.]
    Cantrell and [Mr.] Winsness”). The District Court, after
    reviewing the evidence, did not abuse its discretion in de-
    termining that “the method of the patented inven-
    tion . . . had been performed” during June and July 2003.
    J.A. 171.
    CleanTech’s counterarguments are meritless and mis-
    leading. CleanTech disputes the District Court’s determi-
    nation that the June and July 2003 testing was not
    experimental, arguing that there were “genuine factual
    disputes on [its] ‘commercial’ v[ersus] ‘experimental’” na-
    ture. Appellant’s Br. 39 (capitalization modified). Specifi-
    cally, CleanTech argues that “nearly all” of the Allen
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    30                  GS CLEANTECH CORP. v. ADKINS ENERGY LLC
    factors support the experimental nature of the July 2003
    Proposal. 
    Id. at 40.
    As an initial matter, CleanTech mis-
    represents the Allen factors and supports its arguments
    with testimony that was discredited by the District Court.
    Compare 
    id. (“Allen factors
    [one] and [ten] ask whether the
    inventors ‘needed’ to experiment with the invention ‘under
    actual conditions of use.’” (internal brackets and emphasis
    omitted)), with Allen 
    Eng’g, 299 F.3d at 1353
    (explaining
    that factor one assesses whether there is “the necessity for
    public testing” and factor ten addresses “whether the in-
    vention reasonably requires evaluation under actual condi-
    tions of use”).       CleanTech argues its testing was
    experimental because its claimed invention “clearly”
    “‘needed’ to experiment with the invention ‘under actual
    conditions of use.’” Appellant’s Br. 40 (quoting Allen 
    Eng’g, 299 F.3d at 1353
    ) (internal brackets omitted). The District
    Court did not abuse its discretion in discounting this argu-
    ment, as it explained that a “reduction to practice does not
    require a showing that the method would work acceptably
    in a plant environment, unless the claims require it, and
    the claims here do not.” J.A. 172 (internal quotation marks
    and citation omitted); see In re Cygnus Telecomms. Tech.,
    LLC, 
    536 F.3d 1343
    , 1355 (Fed. Cir. 2008) (explaining that
    a system that would not have worked on a “commercial
    scale[,]” but that “embodied the claims” of the “patents at
    issue[,]” satisfied the “‘ready for patenting’ prong” of the on-
    sale bar). The District Court considered the Allen factors
    and concluded that the offer to Agri-Energy was an offer
    for sale and not for purposes of experimentation. J.A. 167;
    see Allen 
    Eng’g, 299 F.3d at 1352
    –53. For these reasons,
    we conclude that the District Court did not clearly err in
    its determination.
    Second, the District Court found the claimed invention
    was ready for patenting because it had been depicted and
    described in such a way that a PHOSITA would be able to
    practice it. J.A. 172–73; see Hamilton Beach 
    Brands, 726 F.3d at 1375
    (“An invention is ‘ready for patenting’ when
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    GS CLEANTECH CORP. v. ADKINS ENERGY LLC                    31
    prior to the critical date . . . the invention is depicted in
    drawings or described in writings of sufficient nature to en-
    able a [PHOSITA] to practice the invention.” (emphasis
    added) (citation omitted)). Despite CleanTech’s argument
    that its expert opined the Inventors had not prepared
    drawings or other descriptions of the invention that were
    sufficiently specific to enable a PHOSITA to practice it, see
    Appellant’s Reply Br. 18 (emphasis omitted), Appellant’s
    Br. 47, the District Court determined that, while there was
    no “single reference that specifically delineate[d]” the
    method “disclosed by the [Patents-in-Suit], the Ethanol
    [Oil Recovery] System Diagram” in combination “with
    [Mr.] Barlage’s lab tests and results” and “communications
    from [Mr.] Cantrell to Agri-Energy . . . would allow a
    [PHOSITA] to practice the invention of the [Patents-in-
    Suit,]” J.A. 173. The District Court explained that “[t]here
    is no mystery or dispute that the pH, moisture content[,]
    and temperature ranges in the claims of the [Patents-in-
    Suit] are those that occur at the standard operating condi-
    tions of a dry mill ethanol plant.” J.A. 173. CleanTech has
    not shown clear error in these factual findings and we re-
    ject the invitation to reweigh the evidence. Accordingly,
    the District Court did not abuse its discretion in its on-sale
    bar determination.
    B. The District Court Did Not Abuse Its Discretion in
    Concluding that CleanTech and Its Lawyers Made a De-
    liberate Decision to Withhold Material Information with
    the Specific Intent to Deceive the USPTO
    The District Court concluded that CleanTech knew of
    the claimed invention’s offer for sale and reduction to prac-
    tice in the summer of 2003, as well as that information’s
    materiality. J.A. 303, 308. The District Court “conclude[d]
    that the [I]nventors and the[ir] attorneys intentionally
    withheld material information from the [US]PTO during
    prosecution” of the Patents-in-Suit, thereby rendering the
    Patents-in-Suit unenforceable due to inequitable conduct.
    J.A. 312; see 
    Therasense, 649 F.3d at 1290
    (explaining that
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    32                 GS CLEANTECH CORP. v. ADKINS ENERGY LLC
    inequitable conduct requires a showing of clear and con-
    vincing evidence that the patentee “knew of the reference,
    knew that it was material, and made a deliberate decision
    to withhold it”). CleanTech contends that that District
    Court erred in its materiality and intent to deceive find-
    ings. Appellant’s Br. 104–05. We disagree with Clean-
    Tech.
    The District Court did not abuse its discretion in ren-
    dering unenforceable the Patents-in-Suit for inequitable
    conduct. For the reasons discussed above, 
    see supra
    Sec-
    tion II.A, we conclude that the District Court did not abuse
    its discretion in concluding that CleanTech and its attor-
    neys were aware that the claimed invention was ready for
    patenting, as evidenced by documents belatedly or not
    turned over to the USPTO, and that they knew of those
    documents’ materiality. In addition to knowledge and ma-
    teriality, inequitable conduct requires a clear and convinc-
    ing showing that CleanTech “made a deliberate decision to
    withhold” the material information. See 
    Therasense, 649 F.3d at 1290
    . Moreover, “the specific intent to deceive must
    be ‘the single most reasonable inference drawn from the ev-
    idence.’” 
    Id. Here, the
    District Court did not abuse its dis-
    cretion in determining for numerous reasons that
    CleanTech deliberately withheld material information.
    First, the District Court concluded that CleanTech
    knew the July 2003 Proposal to Agri-Energy threatened its
    chances of patenting its ethanol oil recovery method.
    J.A. 299 (explaining “that the [I]nventors made a mistake
    in July/August 2003 and offered their invention for sale to
    Agri-Energy” and “[l]ater . . . took affirmative steps to hide
    that fact from their lawyers, then, later the [US]PTO when
    they learned that it would prevent them from profiting
    from the patents”). This determination is supported by the
    record. In February 2004, the Inventors sought infor-
    mation from the USPTO website about provisional patent
    applications and the on-sale bar. J.A. 252. Days later, Mr.
    Dorisio informed the Inventors about the on-sale bar.
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    GS CLEANTECH CORP. v. ADKINS ENERGY LLC                   33
    J.A. 252. The District Court did not clearly err in finding
    that CleanTech was aware of the on-sale bar and its re-
    quirements. See Energy 
    Heating, 889 F.3d at 1302
    –03
    (concluding that the district court did not abuse its discre-
    tion in finding an inventor’s knowledge that sales of the
    claimed invention prior to the critical date were material,
    and the inventor’s failure to disclose the sales was intended
    to deceive the USPTO).
    Second, the District Court found that the Inventors and
    the attorneys at Cantor Colburn withheld evidence of suc-
    cessful testing in 2003 and made false representations by
    implying that the invention was not reduced to practice un-
    til 2004. J.A. 302 (“[N]ot providing information regarding
    the [I]nventors’ dealings with Agri-Energy or [Mr.] Bar-
    lage[’s] bench-top test raises an inference that the patent-
    ees intended to deceive the [US]PTO—it was pre-critical
    date information that had a direct bearing on the ability of
    the [I]nventors to prove that their claims were patenta-
    ble.”). This finding is supported by the record. Cantor Col-
    burn began representing CleanTech in March 2008 and, by
    at least September 2008, were aware of Mr. Barlage’s test-
    ing in June and July 2003. J.A. 111075. Mr. Winsness in-
    formed Cantor Colburn that the “testing we did in
    June 2003” showed that “a sequence of evaporation fol-
    lowed by centrifugation allows for oil recovery[.]”
    J.A. 111075. Moreover, the Inventors informed Cantor
    Colburn that, based on the summer 2003 testing, the In-
    ventors “believe[d] [that] the process would work on a com-
    mercial scale.”     J.A. 263 (internal quotation marks
    omitted). Cantor Colburn was also in possession of the
    Ethanol Oil Recovery System Diagram and the test reports
    themselves. J.A. 301. Despite possessing this information,
    Cantor Colburn did not provide it to the USPTO during the
    prosecution of the Patents-in-Suit and referenced it only to
    assert that the claimed invention predated Prevost.
    J.A. 301–02, 304–06, 309. Moreover, in June 2009, Cantor
    Colburn filed a letter with the USPTO stating that
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    34                 GS CLEANTECH CORP. v. ADKINS ENERGY LLC
    feasibility testing occurred in May 2004, with no mention
    of the documents dated a year earlier. J.A. 303. This letter
    was filed in the prosecutions of each of the Patents-in-Suit.
    J.A. 304–05. The District Court did not clearly err in its
    finding that CleanTech and Cantor Colburn withheld ma-
    terial evidence from the USPTO. See Molins PLC v. Tex-
    tron, Inc., 
    48 F.3d 1172
    , 1178 (Fed. Cir. 1995) (“[Patentees]
    who are not ‘up front’ with the [US]PTO run the risk that,
    years later, a fact-finder might conclude they intended to
    deceive. This is what appears to have happened here and
    we must affirm the trial court.”); see also 
    id. (“Applicants for
    patents are required to prosecute patent applications in
    the [US]PTO with candor, good faith, and honesty. . . . This
    duty extends also to the applicant’s representatives.” (in-
    ternal footnote and citations omitted)).
    Third, the District Court determined that CleanTech
    and Cantor Colburn “threatened” Agri-Energy to coerce its
    support regarding the critical date for the Patents-in-Suit,
    after the July 2003 Proposal surfaced and during the pen-
    dency of the ’516 and ’517 patents. J.A. 308. Specifically,
    in June 2009, Mr. Winsness traveled to Agri-Energy and
    “offered Agri-Energy a royalty-free license in exchange for
    Agri-Energy’s willingness to admit that the pending pa-
    tents were valid.” J.A. 269. In July 2009, Cantor Colburn
    sent Agri-Energy an email offering “a release of liability for
    any prior use of an extraction system” and indemnification
    “against any liability” in return “for cooperating with
    [CleanTech] and for clarifying the use of the corn oil system
    in 2004.” J.A. 110322. Moreover, Cantor Colburn re-
    quested a statement “confirming and clarifying” certain
    facts relating to the offer. J.A. 110322–23. Agri-Energy’s
    manager testified that he “did not accept the offer from
    [Cantor Colburn and CleanTech] because the statements
    were not true.” J.A. 271. Notably, Cantor Colburn “failed
    to request that Agri-Energy provide any documents” re-
    garding its interactions with the Inventors. J.A. 271. The
    District Court did not abuse its discretion in concluding
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    GS CLEANTECH CORP. v. ADKINS ENERGY LLC                    35
    that these attempts to threaten Agri-Energy spoke to
    CleanTech’s and Cantor Colburn’s intent to deceive the
    USPTO.
    Fourth, the District Court concluded that the Inventors
    and Cantor Colburn made a “patently false” statement in
    the First Cantrell Declaration, by claiming the July 2003
    Proposal was delivered to Agri-Energy after the critical
    date. J.A. 276; see J.A. 307 (“[T]he [I]nventors and attor-
    neys misrepresented to the [US]PTO that the [July 2003
    Proposal] was immaterial by filing the false [First]
    Cantrell . . . Declaration[.]”). The District Court’s determi-
    nation that the declaration was false is supported by the
    evidence. Specifically, it was not until August 2010 that
    Mr. Cantrell told Cantor Colburn that he recalled he had
    personally delivered the July 2003 Proposal to Agri-Energy
    on August 18, 2003. J.A. 272. The attorneys at Cantor
    Colburn testified that they themselves were skeptical of
    the veracity of the claim, as the date specified by Mr.
    Cantrell would alleviate all concerns about the on-sale bar.
    J.A. 272–73. Nonetheless, Cantor Colburn filed the First
    Cantrell Declaration in November 2010 for the ’516 and
    ’517 patent prosecutions, J.A. 276–77, and in the ’484 pa-
    tent prosecution in July 2011, J.A. 277. This was done not-
    withstanding the Inventors’ knowledge that Mr. Barlage
    had practiced the claimed method in June 2003 and they
    had offered to sell the claimed invention to Agri-Energy in
    July or early August of 2003. J.A. 292–93; see Rohm &
    Haas Co. v. Crystal Chem. Co., 
    722 F.2d 1556
    , 1571 (Fed.
    Cir. 1983) (“[T]here is no room to argue that submission of
    false affidavits is not material.”). Moreover, prior to Mr.
    Cantrell’s August 2010 statement, Cantor Colburn had
    prepared a detailed disclosure that included information
    about the June and July 2003 Tests and Report and the
    Ethanol Oil Recovery System Diagram, which the law firm
    had possessed since September 2008. J.A. 308; see
    J.A. 111075–104 (Email from Mr. Winsness to Mr. Hagerty
    Dated September 2008) (providing “some history of testing
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    36                 GS CLEANTECH CORP. v. ADKINS ENERGY LLC
    we did in June 2003 to discover that a sequence of evapo-
    ration followed by centrifugation allows for oil recovery[,]”
    including the June 2003 Report). Following Mr. Cantrell’s
    statements, the disclosure was discarded and never filed in
    any patent prosecution. J.A. 308. Based on this, the Dis-
    trict Court concluded that “[t]he only reasonable inference
    is that [Cantor Colburn] believed the [I]nventors had made
    an offer and, with the feasibility testing letter already be-
    fore the [US]PTO in both prosecutions, . . . which implied a
    later reduction to practice date, they chose advocacy over
    candor.” J.A. 308 (emphases added). The District Court
    did not abuse its discretion in concluding that the “patently
    false” statement in the First Cantrell Declaration was ma-
    terial and supported its intent to deceive determination.
    Fifth, the District Court explained that the Inventors’
    and Cantor Colburn’s failure to correct the false declara-
    tion in the ’484 patent prosecution was “strong evidence of
    intentional deceit[.]” J.A. 309. Specifically, at Mr.
    Cantrell’s September 2011 deposition, where Mr. Cantrell
    and Cantor Colburn “kn[e]w for certain that [Mr.]
    Cantrell’s First Declaration [was] false,” no correction was
    made then or during the following eight months. J.A. 309
    (emphasis added); see J.A 280 (“Most disturbing is that,
    during this period, neither litigation counsel nor [Mr.]
    Hagerty did anything to alert the [US]PTO that [Mr.]
    Cantrell’s First Declaration was false[.]”). In July 2012,
    the Second Cantrell Declaration was filed with the USPTO,
    in which Mr. Cantrell attested that “[a]ttached is an e-mail
    sent from my e-mail account on August 1, 2003” and that
    “[t]he [July 2003 Proposal] attached to the August 1 email
    was unsigned.” J.A. 110274. As the District Court ex-
    plained, the Second Cantrell Declaration provided “the
    false impressions that [Mr.] Cantrell may not have sent the
    [August 2003 Email] and that the unsigned letter had less
    significance than the ‘signed’ one he allegedly hand deliv-
    ered later the same month,” it “repeats false information,”
    and “fails to distinctly point out and/or explain the false
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    GS CLEANTECH CORP. v. ADKINS ENERGY LLC                    37
    information previously provided to the examiner[.]”
    J.A. 283. Based on this evidence, we conclude that the Dis-
    trict Court did not abuse its discretion in concluding that,
    by clear and convincing evidence, the single most reasona-
    ble inference to be drawn from the record was that the In-
    ventors and Cantor Colburn intended to deceive the
    USPTO. See Energy 
    Heating, 889 F.3d at 1302
    –03.
    CleanTech raises numerous counterarguments, all of
    which are unavailing. First, CleanTech argues that the
    District Court’s review of materiality “exceeded the scope
    of the bench trial, which was only on ‘inequitable conduct.’”
    Appellant’s Br. 105. Materiality is, however, an element of
    the inequitable conduct claim and was squarely before the
    District Court. See 
    Therasense, 649 F.3d at 1290
    (“In a case
    involving nondisclosure of information, clear and convinc-
    ing evidence must show that the applicant made a deliber-
    ate decision to withhold a known material reference.”
    (internal quotation marks and citation omitted) (emphasis
    altered)). In fact, CleanTech itself raised materiality in
    pre-trial briefing, contending that the Appellants “will also
    not be able to establish that any of the alleged errors and
    omissions, aside from the misstatements found in [Mr.]
    Cantrell’s first declaration, would have been ‘but-for’ mate-
    rial.” J.A. 63467. Accordingly, the District Court did not
    err in making a materiality determination.
    Second, CleanTech avers that the District Court’s ma-
    teriality finding violated its right to a jury trial. Appel-
    lant’s Br. 105. Given that inequitable conduct is based in
    equity, there is no right to a jury trial. See Am. 
    Calcar, 651 F.3d at 1333
    (“Inequitable conduct is equitable in nature,
    with no right to a jury, and the trial court has the obliga-
    tion to resolve the underlying facts of materiality and in-
    tent.”).
    Third, CleanTech contends that the District Court
    “barred CleanTech from re-litigating materiality” by ex-
    cluding some evidence involving the USPTO’s actions
    Case: 16-2231    Document: 164     Page: 38    Filed: 03/02/2020
    38                 GS CLEANTECH CORP. v. ADKINS ENERGY LLC
    permitting “a continuation in the [Patents-in-Suit]” even
    after the USPTO was provided with evidence of the July
    2003 Proposal and related materials. Appellant’s Br. 105–
    06. The evidence was excluded under Federal Rule of Evi-
    dence 403, because the District Court determined that its
    probative value was outweighed by the likelihood that it
    would confuse and prolong the trial. J.A. 71952–53; see
    Fed. R. Evid. 403 (“The court may exclude relevant evi-
    dence if its probative value is substantially outweighed by
    a danger of one or more of the following: unfair prejudice,
    confusing the issues, . . . undue delay, [or] wasting
    time[.]”). To the extent that CleanTech is contesting the
    Rule 403 determination, it did not do so before the District
    Court and so waives the issue here. See 
    Scheurer, 863 F.3d at 755
    . Accordingly, the District Court did not abuse its
    discretion in reaching its inequitable conduct determina-
    tion. 16
    CONCLUSION
    We have considered the parties’ other arguments and
    each of the remaining issues raised on appeal and cross-
    appeal and find them to be without merit. Accordingly, the
    judgments below are
    AFFIRMED
    16  As we affirm the District Court’s determination
    that the Patents-in-Suit are unenforceable due to the ineq-
    uitable conduct, we need not address CleanTech’s addi-
    tional arguments regarding the other grounds upon which
    the District Court ruled the Patents-in-Suit invalid. See
    Energy 
    Heating, 889 F.3d at 1308
    (concluding that, where
    a trial court’s judgment that a “patent is unenforceable for
    inequitable conduct” is affirmed, this court need “not reach
    the [trial] court’s summary judgment of obviousness, claim
    construction order, or summary judgment of no direct in-
    fringement”).
    Case: 16-2231   Document: 164      Page: 39   Filed: 03/02/2020
    GS CLEANTECH CORP. v. ADKINS ENERGY LLC                39
    COSTS
    Costs to the Appellees and Cross-Appellant.