Ex Parte Benicewicz et al

Patent Trial and Appeal Board

Oct 23, 2017

13742808 (P.T.A.B. Oct. 23, 2017)

United States Patent and Trademark Office UNITED STATES DEPARTMENT OF COMMERCE United States Patent and Trademark Office Address: COMMISSIONER FOR PATENTS P.O.Box 1450 Alexandria, Virginia 22313-1450 www.uspto.gov APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO. 13/742,808 01/16/2013 Brian Benicewicz 074032-0067-US (287224) 4380 123223 7590 10/25/2017 Drinker Biddle & Reath LLP (WM) 222 Delaware Avenue, Ste. 1410 Wilmington, DE 19801-1621 EXAMINER SHEIKH, HAROON S ART UNIT PAPER NUMBER 1724 NOTIFICATION DATE DELIVERY MODE 10/25/2017 ELECTRONIC Please find below and/or attached an Office communication concerning this application or proceeding. The time period for reply, if any, is set in the attached communication. Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the following e-mail address(es): IPDocketWM @ dbr.com penelope. mongelluzzo @ dbr. com DB RIPDocket @ dbr. com PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE BEFORE THE PATENT TRIAL AND APPEAL BOARD Ex parte BRIAN BENICEWICZ,1 Sigmar Brauninger, Gordon Calundann, Max Molleo, and Guoqing Qian Appeal 2017-003867 Application 13/742,808 Technology Center 1700 Before MARK NAGUMO, DONNA M. PRAISS, and CHRISTOPHER L. OGDEN, Administrative Patent Judges. NAGUMO, Administrative Patent Judge. DECISION ON APPEAL BASF timely appeals under 35 U.S.C. § 134(a) from the Final Rejection2 of claims 1, 10, 12, 14, 17, 18, 22-24, 27-33, and 35-43, which are all of the pending claims. We have jurisdiction. 35 U.S.C. § 6. We affirm. 1 The applicant under 37 C.F.R. § 1.46, and hence the appellant under 35 U.S.C. § 134, is the real party in interest, identified as BASF SE (“BASF”). (Appeal Brief, filed 9 May 2016 (“Br”), 1.) 2 Office Action mailed 19 February 2016 (“Final Rejection”; cited as “FR”). Appeal 2017-003867 Application 13/742,808 OPINION A. Introduction3 The subject matter on appeal relates to proton-conducting polymer membranes made from polyazoles.4 Such membranes may be prepared from a polybenzimidazole (“PBI”) treated (doped) with phosphoric acid to provide the desired proton-conductivity. (Spec. 1, 5th para; see also Uensal5 2 [0024].) According to the '808 Specification, similar “second generation” polyazole membranes are known from prior work. (Spec. 2, citing U.S. Patent Application Publication 2004/0096734 A1 (issued as U.S. Patent No. 7,384,552 B2 on 10 June 2008 to Gordon Calundann et al.)) The membranes are said to be useful as polymer electrolyte membranes (“PEM”) in high temperature6 fuel cells operated above 100°C. (Id. ) Such high temperatures are said to be possible because the membranes do not need to be moistened with water to transport protons. (Uensal 2 [0027].) The higher 3 Application 13/742,808, Proton-conducting membrane, method for their production and their use in electrochemical cells, filed 16 January 2013, claiming the benefit of a provisional application filed 17 January 2012. The '808 Application has been published as U.S. Patent Application Publication2013/0183603 A1 (18 July 2013). Werefertothe “’808 Specification,” which we cite as “Spec.” 4 Throughout this Opinion, we will use the generic term “polyazole” and the sub-generic term “polybenzimidazole” interchangeably, as polybenzimid- azoles are the principal polyazoles of interest. 5 The full cite for Uensal is provided infra at 5 n.10. 6 “Conventional” PEMs, such as those based on perfluorosulfonic acids (e.g., Nafion® [DuPont], are said to depend on water clusters for proton transport, and therefore require operational temperatures below 100°C. (Benicewicz Declaration 2,14 (full cite at 7 n.l 1, infra)', see also Molleo 150, col. 1: (full cite at 9 n.13, infra); and Uensal 1 [0006]-[0007].) 2 Appeal 2017-003867 Application 13/742,808 temperature operation is also said to allow distinctly higher concentrations of CO impurities (Spec. 1, last para.; Uensal 2 [0028]) as well as reduced [platinum-based] catalyst loadings (Spec. 2, 1st para.; Uensal 2 [0028]). However, still greater resistance to mechanical stress, including greater stretchability and resilience, is said to be desired to withstand compression forces when assembling the fuel cell stack, as well as improved creep resistance {id. at para, bridging 2-3), which is associated with a higher Young’s [tensile elastic] modulus, {id. at 25, 4th full para.) Briefly, the improved membranes are formed by: A) mixing certain monomers in polyphosphoric acid (“PPA”); B) heating the mixture to form polyazoles; C) forming a membrane by spreading the polyazoles on a carrier such as an electrode (e.g., by casting, spraying, or knife coating; id. at 7, 2d para.); D) optionally heating the membrane to cause further polymerization (monitored by the increase in intrinsic viscosity (“I. V.”)7; id. at 4th-5th para.); E) treating the membrane at a temperature most preferably between room temperature and 90°C {id. at 18, 1st full para.) in the presence of water to hydrolyze the polyphosphoric/phosphoric acid and cause a “sol-gel transfer of the polyazole/polyphosphoric/phosphoric acid mixture” {id. at para, bridging 17-18); and F) removing the membrane from the carrier (i.e., the membrane is self-supporting). 7 The Specification (and other patent documents, e.g., Uensal) use the term “intrinsic viscosity.” Dr. Benicewicz, in his Declaration and in the published technical papers cited therein, uses the term “inherent viscosity,” apparently in reference to the same quantity, notwithstanding formal definitional differences. We assume, without deciding, that values of I.V. reported in the present record refer to the same measured quantity, although we attempt to use the term used by the particular document cited. 3 Appeal 2017-003867 Application 13/742,808 Claim 1 is representative and reads: A proton-conducting polymer membrane based on polyazoles, prepared by a process comprising the steps of A) mixing: one or more aromatic tetraamino compounds selected from the group consisting of 2,3,5,6-tetraaminopyridine, 3,3',4,4'-tetraaminodiphenylsulfone, 3,3',4,4'-tetraaminodiphenyl ether, 3,3',4,4'-tetraaminobiphenyl, 1.2.4.5- tetraaminobenzene, 3,3',4,4'-tetraaminobenzophenone, 3,3',4,4'-tetraaminodiphenylmethane, 3,3',4,4'-tetraaminodiphenyldimethyl-methane, and the salts of each thereof; and one or more aromatic carboxylic acids or esters thereof selected from the group consisting of - pyridine-2,5-dicarboxylic acid, pyridine-3,5-dicarboxylic acid, pyridine-2,6-dicarboxylic acid, pyridine-2,4-dicarboxylic acid, 4-phenyl-2,5-pyridinedicarboxylic acid, 3.5- pyrazoledicarboxylic acid, 2,6-pyrimidinedicarboxylic acid, 2,5-pyrazinedicarboxylic acid, 2,4,6-pyridinetricarboxylic acid, benzimidazole-5,6-dicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, 5-hydroxyisophthalic acid, 4- hydroxyisophthalic acid, -2-hydroxyterephthalic acid, 5- aminoisophthalic acid, 5-N,N-dimethylaminoisophthalic acid, 5-N,N-diethylaminoisophthalic acid, 2.5- dihydroxyterephthalic acid, 2,6-dihydroxyisophthalic acid, 4.6- dihydroxyisophthalic acid, 2,3-dihydroxyphthalic acid, 2,4-dihydroxyphthalic acid, 3,4-dihydroxyphthalic acid, 1,8-dihydroxynaphthalene-3,6-dicarboxylic acid, in polyphosphoric acid to form a solution and/or dispersion, B) heating the mixture from step A), and polymerizing until an intrinsic viscosity of at least 0.8 dl/g, to obtain polyazole polymer, C) forming a membrane using the polyazole polymer obtained in step B) on a carrier or on an electrode, D) optionally heating the membrane on the carrier or electrode, E) treating the membrane formed in step C) or D) in the presence of water or moisture, and F) removing the membrane from the carrier, 4 Appeal 2017-003867 Application 13/742,808 wherein the total solid content of the polyazole polymer in the membrane is at least 10% by weight and up to about 25% by weight and said total content includes any acids, and water being present, but excludes any optional additives, the membrane has a Young[’]s modulus of at least 4.5 MPa. (Br., Claims App. i; some indentation, paragraphing, and emphasis added.) The Examiner maintains the following ground of rejection8,9: Claims 1, 10, 12, 14, 17, 18, 22-24, 27-33, and 35-43 stand rejected under 35 U.S.C. § 103(a) in view Uensal.8 9 10 B. Discussion The Board’s findings of fact throughout this Opinion are supported by a preponderance of the evidence of record. BASF does not dispute the Examiner’s findings (FR 3 4) that Uensal discloses mixing, in polyphosphoric acid (Uensal 3 [0039]), monomers, including aromatic tetraamino compounds {id. at 5 [0080]-[0081]) and aromatic dicarboxylic acids or esters {id. at 6 [0110], 7 [0113]) that are nearly the same as the lists recited in claim 1, part A). In particular, BASF 8 Examiner’s Answer mailed 1 December 2016 (“Ans.”). 9 Because this application was filed before the 16 March 2013, effective date of the America Invents Act, we refer to the pre-AIA version of the statute. 10 Oemer Uensal et al., Proton conducting polymer membrane comprising phosphoric acid groups containing polyazoles and the use thereof in fuel cells, U.S. Patent Application Publication 2006/0008690 Al (2006), issued as U.S. Patent No. 7,736,778 B2 (15 June 2010). The Uensal patent is assigned to BASF Fuel Cell GmbH, and has, among its co-inventors, Gordon Calundann and Brian Benicewicz, who are co-inventors of the '808 application on appeal. 5 Appeal 2017-003867 Application 13/742,808 does not dispute the Examiner’s finding (made with respect to claims 17 and 18; FR 6,11. 6-14), that Uensal teaches (Uensal 11 [0165]) [although does not claim] PBIs having monomer units without phosphonic acid groups. Nor does BASF dispute the Examiner’s finding that Uensal discloses heating the mixture {id. at 3 [0040]) to obtain intrinsic viscosities in the range of 1 to 5 dl/g, thus meeting the requirement of intrinsic viscosities of at least 0.8 dl/g. BASF also does not dispute the Examiner’s findings that Uensal discloses steps corresponding to C), applying a layer to a carrier {id. at 3 [0041]); and to E) and F), treating the membrane until it is self-supporting {id. at [0042]) in the presence of moisture or water {id. at 13 [0198]). Nor does BASF dispute the Examiner’s findings that Uensal discloses obtaining a Young’s modulus [“YHU”] of at least 2 MPa which overlaps the claimed range of “at least 4.5 MPa” (FR 5, 1st full para., citing Uensal 13 [0200].) Instead, BASF urges (Br. 5-6) that the Examiner errs in determining (FR 5) that, on the basis of Uensal’s teachings, a person having ordinary skill in the art would have had the guidance to make the “careful selection” of the “one or more aromatic carboxylic acids or esters thereof’ with a reasonable expectation of obtaining membranes having a total solid contents of the solid polyazole polymer in the membrane of at least 10% by weight, including any acids and water, but excluding any optional additives. (Br. 5, 2d para.) On the contrary, BASF urges, Uensal would not have enabled a person of ordinary skill in the art to make the claimed membrane. (Br. 5, 6 Appeal 2017-003867 Application 13/742,808 last sentence.) In support of these arguments, BASF relies on the declaration11 of Dr. Benicewicz, one of the inventors. Dr. Benicewicz testifies that he holds the SmartState Endowed Chair in Polymer Nanocomposites at the University of South Carolina (Benicewicz 3,^8), and that he has extensive education and research experience in the field of polymer chemistry dating from at least 1976 {id. at 1,11 to 3,17), including more than 18 years of experience managing research programs on polybenzimidazole (“PBI”) membranes (id. at 3,19). We find Dr. Benicewicz well-qualified to testily as an expert on the technical subject matter of this appeal. Dr. Benicewicz lists several “important technical advances or teachings described” in one of his first publications on PBI membrane technology,12 which was filed as Exhibit A to his Declaration. {Id. at 3-5, 110.) Among these advances and teachings, Dr. Benicewicz highlights the formation of PBIs from 3,3'-4,4'-tetraaminobiphenyl (“TAB”) and isophthalic acid (benzene-1,3-dicarboxylic acid, also known as “meta- phthalic acid,” because the carboxyl groups are positioned “meta” to each other at the 1- and 3-positions on the benzene ring); and from TAB and terephthalic acid (“TPA,” benzene-1,4-dicarboxylic acid, also known as “para-phthalic acid,” because the carboxyl groups are positioned “para” to each other at the 1- and 4-positions on the benzene ring). {Id. at 3,110.A.) 11 Dr. Brian Benicewicz, Declaration under 35 U.S.C. § 132, filed 30 December 2015 (“Benicewicz”). 12 LiXiang Xiao et al., High-temperature polybenzimidazole fuel cell membrane via a sol-gel process, 17 Chem. Mater. 5328-33 (2005). Dr. Benicewicz is listed as the corresponding author. 7 Appeal 2017-003867 Application 13/742,808 The polymerizations were conducted in PPA as the polymerization solvent, yielding Intrinsic Viscosity (“I.V.”) values of 1.3 to 2.0 dL/g for meta-PBI, and of 1.5 to 3.0 dL/g for the para-PBI. (Id.) Furthermore, both the PPA solvent and the PBI product are hygroscopic, so they absorb moisture from the air. (Id. at 4,110.B.) The condensed water is said to hydrolyze PPA (a good solvent for PBI) to phosphoric acid (“PA,” a poor solvent for PBI). (Id.) The solution temperature also reportedly drops from the ~200-220°C casting temperature to room temperature. (Id.) The change in solubility and the temperature drop are said to induce a transition from the solution state to the gel state, producing proton-conducting PA-doped PIB membranes in a single step. (Id.) The mechanical properties of the resulting membranes were found to be “remarkably high,” with an average tensile strength in the range of 1.0 to 3.5 MPa and elongation at break of 150-390%. (Id. at 110.E.) Both properties were found to be “critically dependent on the molecular weight, as measured by the inherent viscosity (I.V.) of the PBI polymer.” (Id.) Neither the total solids content of these polyazole polymers in the membrane, nor the Young’s modulus, was reported in Exhibit A. Dr. Benicewicz testifies that “first generation” PBI membrane- electrode assemblies (“MEAs”) were based on “para-PBI” prepared from TAB and TPA as described in Exhibit A. (Id. at 5,111). According to Dr. Benicewicz, the para-PBI-membranes have been shown to operate for over 15,000 hours under steady state conditions. (Id.) Dr. Benicewicz does not cite any authority for this statement. 8 Appeal 2017-003867 Application 13/742,808 However, according to Dr. Benicewicz “second generation fuel cells will have an operational target of 40,000 hours,” and “[t]o reach this operational target, a new compositional PBI-based membrane with greater creep resistance is required.” {Id. at 112.) Dr. Benicewicz does not explain why this is so, and he does not cite any authority for these statements. Dr. Benicewicz testifies further that “[t]he para-PBI-membranes have a maximum solid content of about 5% to 7% because of the limited solubility of para-PBI in PPA or the polymerization medium becomes too viscous to cast into a membrane.” {Id.) Again, Dr. Benicewicz does not direct our attention to any evidence, published or not, supporting these statements. Dr. Benicewicz re-emphasizes, although again without explanation or citation to the literature, that “PBI-membranes with a greater solid content are likely needed to prepare ME As with greater creep resistance.” {Id. atl 13.) Dr. Benicewicz also states that Uensal (on which Dr. Benicewicz is listed as a co-inventor) {id.) reports one of his group’s attempts at preparing a high solid content PBI {id.) Dr. Benicewicz describes another report, filed as Exhibit B13 to his Declaration, of the chemistry and trends for PBIs from five different polymer types, as part of their effort to find PBI-membranes having greater 13 M.A. Molleo et al., High polymer content 2,5-pyridine-polybenzimidazole copolymer membranes with improved compressive properties, 15 Fuel Cells 150-59 (2015) (received 6 August 2014; published online 28 November 2014, both after the filing date of the '808 application). Dr. Benicewicz is listed as the corresponding author, and M.A. Molleo is also a co-inventor. 9 Appeal 2017-003867 Application 13/742,808 solid content in order to prepare membrane electrode assemblies for fuel cells having an operational target of 40,000 hours. {Id. at 6-7,114.) Among the features highlighted by Dr. Benicewicz, more polar monomers, and meta-monomers, provide greater solubility PBIs compared to para-PBI. {Id. at 7 14.B, 14.C.) However, greater solubility, which affords higher molecular weight, is said to lead to decreased thermal stability. In particular, a pure 3,5-pyr-PBI (i.e., formed from 3,5-pyridinedicarboxylic acid and TAB) is said not form a stable gel at room temperature. {Id. at 114.E.) Dr. Benicewicz also describes a third report, filed as Exhibit C14 to his Declaration, describing further studies of PBI-membranes, particularly the relation between creep behavior, solids content, and monomer composition. {Id. at 7,115, to 8,116.) Dr. Benicewicz highlights the discovery that a small molar amount (17%) of 3,5-pyr-PBI (a “meta-PBI”) in para-PBI (83%) has sufficient solubility in PPA to produce a membrane with 15% total solids content (“pre-conditioning”), that is stiff and creep resistant. {Id. at 116.B.) Dr. Benicewicz disputes {id. at 8,117, to 10,123) the Examiner’s finding that “Uensal teaches the total solid content of polyazole-forming monomers in the mixture from step A is from 1 to 30% by weight [par. 0122].” (FR 5,11. 3^4.) The cited passage in Uensal reads in full, “[t]he mixture prepared in step A) preferably comprises at least 0.5% by weight, in particular from 1 to 30% by weight and particularly preferably 14 Xiaoming Chen et al., High temperature creep behavior of phosphoric acid-polybenzimidazole gel membranes, J. Polymer Sci. B: Polymer Physics (2015) DOI: 10.1002/polb23791 (received 30 April 2015, accepted 13 July 2015; also post-filing art). 10 Appeal 2017-003867 Application 13/742,808 from 2 to 15% by weight, of monomers for preparing polyazoles.” (Uensal 7 [0122].)15 It is true, as Dr. Benicewicz points out, that this passage refers to monomer content, which, he insists correctly, “does not equate to the total solid content of polyazole monomer [sic: polymer] present in the resulting membrane following the hydrolysis in step E of the claimed process.” (Benicewicz 9,119.) However, it is also true, as the Examiner points out (FR 5,11. 1-3), that the amounts of monomer suggested by Uensal overlap the amounts of monomer disclosed in the '808 Specification to obtain the desired total content of polyazole polymers in the membrane. The passage in the '808 Specification cited by the Examiner reads in most relevant part: It has been found that the total content of monomers in step A) has to be chosen so that the total content of all polyazole polymers in the membrane is at least 5% by weight and up to about 25% by weight and said total content includes any acids, such as polyphosphoric acid and/or phosphoric acid and water being present, said total content excluding however any optional additives. Usually, the amount of monomers is at least 5% by weight and up to about 25% by weight, preferably at least 8% by weight and up to about 25%) by weight, most preferred at least 10% by weight and up to about 25%> by weight of the total mixture including the polyphosphoric acid. (Spec. 6, 1st full para.; emphasis added.) Thus, there is substantial overlap of the particularly preferred monomer content of 2-15% by weight disclosed by Uensal and the preferred monomer content of 5-25% (most preferred, 10-25%) by weight disclosed by the '808 Specification. 15 This passage corresponds to the Uensal '778 Patent, col. 12,11. 57-60, cited by Dr. Benicewicz. 11 Appeal 2017-003867 Application 13/742,808 Given that the required polymerization and membrane-forming steps are also disclosed by Uensal (as the Examiner takes care to point out, and as BASF does not dispute), and given that Uensal mentions specifically most if not all of the aromatic and heteroaromatic diamine monomers, as well as all of the aromatic and heteroaromatic diacid monomers, we are not persuaded that the Examiner’s mis-reading of paragraph [0122] was harmful. It is well-established that when a prior art reference discloses a way of obtaining a set of products, and all of the ingredients necessary to form the products, as well as indications that key intermediates are also obtainable-here, the high intrinsic viscosity resulting from step B) of greater than 0.8 dL/g (Uensal 11 [0166] discloses intrinsic viscosities of 1 to 5 dL/g)-prima facie obviousness usually is present. At the heart of BASF’s argument against obviousness is the contention that the routineer would have required undue experimentation to select the particular monomers disclosed by Uensal that would result in the high total solid content of polyazole polymer and a Young’s modulus of at least 4.5 MPa required by claim 1. This argument requires several steps. First, our reviewing court has held “a presumption arises that both the claimed and unclaimed disclosures in a prior art patent are enabled.” Amgen Inc. v. Hoechst Marion Roussel, Inc., 314 F.3d 1313, 1355 (Fed. Cir. 2003). The court subsequently extended that holding to prior art publications as well as patents: [consistent with the statutory framework and our precedent, we therefore hold that, during patent prosecution, an examiner is entitled to reject claims as anticipated by a prior art publication or patent without conducting an inquiry into whether or not that prior art reference is enabling. As long as 12 Appeal 2017-003867 Application 13/742,808 an examiner makes a proper prima facie case of anticipation by giving adequate notice under § 132, the burden shifts to the applicant to submit rebuttal evidence of nonenablement. In re Antor Media Corp., 689 F.3d 1282, 1289 (Fed. Cir. 2012). The extension to obviousness is immediate. That some experimentation may be necessary is not a bar to a determination that a reference would have been enabling. Johns Hopkins Univ. v. CellPro, Inc., 152 F.3d 1342, 1360 (Fed. Cir. 1998) (“a considerable amount of experimentation is permissible, if it is merely routine.”) What degree of experimentation would have been routine depends in part on the level of ordinary skill. Our reviewing court has instructed that the art of record in an examination is frequently the best guide to the level of skill. In re GPAC Inc., 57 F.3d 1573, 1579 (Fed. Cir. 1995) (“the level of ordinary skill in the art of [the invention] was best determined by appeal to the references of record.”) In this case, Uensal includes two of the present inventors, namely Gordon Calundann and Brian Benicewicz, while Exhibit A includes Benicewicz. Exhibits B and C, while not prior art, include additional inventors. The preponderance of the evidence suggests that the ordinary inventor in this complex technical field is highly educated, sophisticated in polymer science and in the synthesis, development, and testing of polymers for applications requiring high mechanical and thermal resilience. We therefore reject BASF’s contention that the Examiner has imputed too high a level of ordinary skill in the art. However, the state of the art is also an important factor for the evaluation of what amount of experimentation would have been undue. A less predictable art requires more experimentation, and thus lowers the bar 13 Appeal 2017-003867 Application 13/742,808 to how much experimentation is undue. Uensal, according to the testimony of Dr. Benicewicz, reports an attempt to obtain second generation PIB membranes for advanced fuel cells. Thus, a person reading Uensal is not encountering pioneering work unveiling previously uncharted territory. That is, the chemical and mechanical properties desired for polymer electrolyte membranes (“PEM”) for fuel cells capable of operating at high temperatures for extended periods of time, that have considerable mechanical strength as well as chemical resistance along with good conductance of protons-were already well known. Moreover, as explained supra, Uensal teaches the general method of making PIBs by condensation in PPA as the solvent, including preferred amounts of monomers that overlap preferred amounts disclosed in the Specification. All of the particular monomers recited in the claims, including the shorter lists of dicarboxylic acids recited in claims 10, 36, 39, and 40, are disclosed as preferred monomers without phosphonic acid groups. (Uensal 5 [0081] (amines); 6 [0100] (aromatic dicarboxylic acids, the first); 7 [0113] (a list of ten heteroaromatic dicarboxylic acids identical to the list recited in claim 10, and including the nine such acids recited in claims 36 and 39).) Selecting such acids from preferred diacids, where the list is identical, would not have required insight beyond the ordinary. Uensal also teaches forming the membrane on a carrier or on an electrode (Uensal 14 [0215]), and treating the membrane in the presence of water vapor to effect the sol-gel transition, resulting in a PA-doped PIB membrane. Uensal teaches expressly that the partial hydrolysis of the PPA results in strengthening of the membrane. {Id. at 13 [0199]-[0200].) The ultimate use of the membranes as proton-conducting PEMs for high- 14 Appeal 2017-003867 Application 13/742,808 temperature fuel cells was recognized by Uensal (id. at 2 [0028]-3 [0037]), as was the goal of high molecular weight, measured as intrinsic viscosity of 0.3 to 10 dl/g, preferably from 1 to 5 dl/g (id. at 11 [0166]) in order to achieve the desired properties. Dr. Benicewicz testifies that the chemistry and physical properties of PBIs are complicated, and that higher solubility arising from increased polarity as well as the shape of the monomers is correlated both with higher molecular weight polymers as well as decreased thermal stability. What is lacking, however, is any direct comparison to the teachings of Uensal, including an explanation of why the selection of monomers based on Uensal’s teachings of those monomers would not have been likely to lead to the membranes now claimed.16 We conclude that BASF has not shown harmful error in the conclusion that the presently claimed subject matter would have been prima facie obvious in view of the teachings of Uensal. To the extent that BASF’s argument can be understood as a rebuttal of a prima facie case of obviousness based on unexpected results- unpredictability and unexpected results are often two sides of the same coin-it is difficult to conclude that the evidence proffered is commensurate in scope with the claimed subject matter. This is in part due to the 16 The sole Example in Uensal (isophthalic acid, 3,5-dicarboxy-l-phenyl- phosphonic acid, TAB; Uensal 15 [0228]-[0229]) appears to be most similar to Specification Example 4, 2,5-pyridine-r-Meta-BPI (2,5-pyridine dicarboxylic acid, isophthalic acid, and TBA), providing a membrane with 18.90 wt% polymer and a Young’s Modulus of 6.55 MPa (Spec. 27-28). 15 Appeal 2017-003867 Application 13/742,808 functional limitations by which the subject matter is largely defined.17 Accordingly, we decline to credit Dr. Benicewicz’s testimony as conclusive evidence of unexpected results. On the present record, we are not persuaded that the evidence in favor of non-enablement outweighs the generic but highly suggestive, disclosure of Uensal in favor of obviousness.18 17 There appear to be, for example, no working examples of PBI membranes within the scope of the claims that are not terpolymers, and several indications that certain two-component polymers cannot be produced with the required solid polymer content and Young’s Modulus; but the claims encompass, potentially, two-component copolymers. We do not suggest that the Examiner erred in not entering a rejection for lack of enablement as to scope, as the evidentiary burden and the burden of persuasion have been set, properly, quite high. In re Marzocchi, 439 F.2d 220, 224 (CCPA 1971) (“it is incumbent upon the Patent Office, whenever a rejection on this basis is made, to explain why it doubts the truth or accuracy of any statement in a supporting disclosure and to back up assertions of its own with acceptable evidence or reasoning which is inconsistent with the contested statement.”) 18 In the event of further examination, we remind both the Examiner and BASF that further evidence for and against obviousness must be evaluated in the context of all the evidence of record, and that the present determination is not set in concrete. As our reviewing court has counseled, “a final finding of obviousness may of course be reached, but such finding will rest upon evaluation of all facts in evidence, uninfluenced by any earlier conclusion reached by an earlier board upon a different record.” In re Rinehart, 531 F.2d 1048, 1052 (CCPA 1976). 16 Appeal 2017-003867 Application 13/742,808 C. Order It is ORDERED that the rejection of claims 1, 10, 12, 14, 17, 18, 22-24, 27-33, and 35-43 is affirmed. No time period for taking any subsequent action in connection with this appeal may be extended under 37 C.F.R. § 1.136(a). AFFIRMED 17