Ex Parte Devine et al

Board of Patent Appeals and Interferences

Apr 26, 2010

10490422 (B.P.A.I. Apr. 26, 2010)

UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
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Ex parte JOHN NEIL DEVINE
and BRIAN WILSON
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Appeal 2009-003782
Application 10/490,422
Technology Center 1700
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Decided: April 26, 2010
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Before CHUNG K. PAK, PETER F. KRATZ, and MARK NAGUMO,
Administrative Patent Judges.

NAGUMO, Administrative Patent Judge.

DECISION ON APPEAL
Appeal 2009-003782
Application 10/490,422

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A. Introduction1
John Neil Devine and Brian Wilson (“Devine”) timely appeal under
35 U.S.C. § 134(a) from the final rejection2 of claims 1-13 and 16-19.3
We have jurisdiction under 35 U.S.C. § 6. We REVERSE.
The subject matter on appeal relates to a fuel cell having a polymer
electrolyte membrane made from particular copolymers that are said to be
easily and inexpensively made and to provide surprisingly low boiling water
uptake. The 422 Specification explains that, in a polymer electrolyte
membrane fuel cell, hydrogen introduced at the fuel cell anode undergoes
the electrochemical reaction
2H2 → 4H+ + 4e-
The hydrogen ions then migrate through a conduction polymer electrolyte
membrane to the cathode, where they react with oxygen in the reaction
O2 + 4H+ + 4e- → 2H2O
with the evolution of heat. (Spec. 1.)

1 Application 10/490,422, Cells, filed 28 April 2004, as the national stage of
PCT GB02/04242, filed 18 September 2002, and claiming the benefit under
35 U.S.C. § 119(a) of an application filed in the UK on 26 September 2001.
The specification is referred to as the “422 Specification,” and is cited as
“Spec.” The real party in interest is listed as Victrex Manufacturing
Limited. (Appeal Brief, filed 17 March 2008 (“Br.”), 3.)
2 Office action mailed 17 July 2007 (“Final Rejection”; cited as “FR”).
3 The Examiner objects to claims 14 and 15 as depending from a rejected
independent claim, but indicates the subject matter is allowable if presented
in independent form. (FR 6.)
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According to the 422 Specification, it is known in the art that high
conductivity materials and good water absorbing properties are desired for
polymer electrolyte membranes (“PEM”). (Spec. 2, ll. 4-8.) Sulphonate4
groups, -SO3M, are known to provide ion-exchange sites that increase the
conductivity of a polymeric material; but excessive water solubility or
uptake—especially at the high temperatures found in an operating fuel
cell—is said to degrade the polymeric material and to decrease the useful
lifetime of the fuel cell. (Id. at 2, ll. 8-20.)
The inventors have provided a fuel cell using sulphonated polymer as
the PEM that is said to overcome these problems while being easy to make,
inexpensive, and readily reproducible on a commercial scale. (Spec. 4,
ll. 11-26.)
Representative Claim 1 is reproduced from the Claims Appendix to
the Principal Brief on Appeal:
1. A fuel cell or an electrolytic cell comprising
an ion-conductive polymeric material which includes a first
repeat unit of formula:
-(O-Ph1-CO-Ph1-O-Ph1-CO-Ph1)- I
and a second repeat unit
of formula
-(O-Ph2-O-Ph3-CO-Ph4)- II
or of formula
-(O-Ph2-O-Ph3-SO2-Ph4)- III
wherein Ph1, Ph2, Ph3 and Ph4 independently represent phenyl
moieties and

4 We follow the British spelling used by Devine.
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wherein said second repeat unit is provided with ion-
exchange sites.
(Claims App., Br. 14; indentation and paragraphing added.)
The Examiner has maintained the following ground of rejection:5
Claims 1-13 and 16-19 stand rejected under
35 U.S.C. § 103(a) in view of the combined teachings of
Sakai6 and Rose.7
Devine contends the Examiner failed to establish a prima facie case of
obviousness because neither Sakai nor Rose are concerned with the problem
solved by the inventors. (Br. 10, 1st para.) More specifically, Devine
argues that Rose does not teach that the polyaryletherketones are ion
conductive. (Id. at 2d para.) Moreover, according to Devine, Rose discusses
water absorption capacity only at ambient temperatures, in keeping with the
suggested applications of ultrafiltration, desalinization, and micro-organism
removal. (Id.) Devine concludes that no motivation to combine the
teachings of the references “in the context of the presently claimed cells” has
been established. (Id. at 12, first full para.) Devine argues further that
the 422 Specification shows unexpectedly low water absorption by the
sulphonated copolymer recited in the claims. (Br., para. bridging 9-10.)
Devine does not raise separate arguments for the dependent claims.

5 Examiner’s Answer mailed 9 June 2008. (“Ans.”).
6 Osamu Sakai et al., Polymer Electrolytic Fuel Cell and Method for
Producing the Same, U.S. Patent 7,097,932 B1 (29 August 2006), based on
an international application accorded an effective date of 20 March 2002.
7 John B. Rose, Sulphonated PolyaryletherKetones, U.S. Patent 4,419,486
(1983).
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The Examiner responds that the references need not address the same
problem as the one addressed by the inventors. (Ans. 9, 2d full para.) The
Examiner maintains further that the sulphonated copolymers taught by Rose
have the composition required by formulas I and II, and that the ion-
exchange function of the sulphonate groups is the same in the reference
copolymers as in the Nafion ionomer used as the polymer electrolyte
membrane by Sakai. (Id. at 10, 2d full para.) The good water management
properties are, in the opinion of the Examiner, sufficient, together with the
ion transfer equivalance to Nafion, sufficient to provide motivation to use
the polymer taught by Rose as the ion conductive membrane in the cell
taught by Sakai. (Id. at 11, first full para.) The evidence of unexpected
results is unconvincing, according to the Examiner, “because the copolymer
of Rose is the same copolymer as that claimed, and would provide the same
results as Table 2 [of the Specification].” (Id. at last para.)
The issue dispositive of this appeal is whether the Examiner has
established that a person having ordinary skill in the art would have had a
reasonable expectation of successfully substituting the sulphonated
copolymers described by Rose for the Nafion polymer used in the polymer
electrolyte membrane in the fuel cell described by Sakai.
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B. Findings of Fact
Findings of fact throughout this Opinion are supported by a
preponderance of the evidence of record.
The 422 Specification
1. The 422 Specification provides a diagram of a fuel cell in Figure 1,
which is reproduced below:

{Figure 1 is said to show a fuel cell}
2. Hydrogen gas, H2, is introduced at the anode, where it is converted
to H+ and electrons, e-, which traverse the polymer electrolyte membrane to
the cathode, where they react with oxygen, O2, to form water, with the
evolution of heat. (Spec. 1, ll. 8-31.)
3. The polymer electrolyte membrane is said to be at least 0.5 μm thick
up to, most preferably, less than 0.05 mm [i.e., 50 μm]. (Spec. 16, ll. 28-31.)
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4. According to the 422 Specification, of all the phenyl groups in
formulas I, II, and III, the -O-Ph2-O- phenyl groups are most easily
sulphonated (e.g., by 98% sulphuric acid at 65°C for 21 hours (Example 2 at
Spec. 23, ll. 14-16)), “but relatively deactivated Ph1, Ph3 and Ph4 phenyl
groups generally cannot be sulphonated.” (Spec. 18, ll. 20-22.)
Sakai
5. Sakai describes polymer electrolyte fuel cells in which the anode or
cathode has “at least either of hydrogen ion conductivity and gas
permeability . . . [that] varies in a thickness direction. (Sakai, abstract;
col. 3, ll. 61-65.)
6. In embodiments, according to Sakai, “[i]t is preferable that the
porosity of the gas diffusion layer is high at the electroconductive separator
side and low at the catalyst layer side.” (Sakai, col. 4, ll. 17-19.)
7. In preferred embodiments, the polymer-electrolyte membrane has a
CF2 backbone with oxy-perfluorocarbon side groups terminated by a
sulfonic acid group. (Sakai, col. 6, ll. 1-15.)
8. Such polymers are said to be commercially available under the
tradenames Flemion (Sakai, col. 8, ll. 47-49) and Nafion (id. at col. 9,
ll. 1-3).
9. Sakai also teaches that “as the hydrogen ion conductive polymer
electrolyte membrane, those that have conventionally been utilized may be
used.” (Sakai, col. 6, ll. 29-31.)
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Rose
10. Rose describes polymers comprising repeat units of formula A
A
and repeat units of formula B
B
in which substantially all of the A units are sulphonated, and substantially all
of the B units are not sulphonated after treatment with H2SO4. (Rose, col. 1,
l. 56 through col. 2, l. 54.)
11. Formula A is the same as formula II, supra.
12. Formula B is the same as formula I, supra.
13. The sulphonated copolymers are said to be hydrophilic and to
absorb 2-40 weight% water at ambient temperature. (Rose, col. 2, ll. 28-30.)
14. According to Rose, the copolymers are “potentially useful as
membrane materials, e.g., for ultra-filtration processes, e.g., desalination and
removal of micro-organism, since they are not only hydrophilic in character
but retain considerable strength even when containing a significant quantity
of water (e.g. up to 20 weight % water).” (Rose, col. 2, ll. 28-36.)
15. Rose does not describe any properties of the copolymers at
temperatures above ambient.
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C. Discussion
Claimed subject matter can be shown to be obvious, and thus
unpatentable, if it is shown that a person having ordinary skill in the art
would have had a reasonable expectation of successfully combining prior art
teachings to achieve the claimed invention. See, e.g., Velander v. Garner,
348 F.3d 1359, 1379 (Fed. Cir. 2003). That reasonable expectation of
success is to be assessed from the perspective of one of ordinary skill in the
art at the time the invention was made. Life Techs., Inc. v. Clontech Labs.,
Inc., 224 F.3d 1320, 1326 (Fed. Cir. 2000).
As the Examiner noted, Devine’s criticism that neither Sakai nor Rose
are concerned with the problem solved by the inventors is not dispositive of
nonobviousness. However, Sakai is concerned with making operable fuel
cells, and the 422 Specification teaches that the stability of the polymer
electrolyte membrane at elevated temperatures is a critical property. The
Examiner has not disputed that high temperature performance of the PEM is
critical in fuel cell operations. The Examiner acknowledges that Rose does
not disclose high-temperature water absorptive properties of the sulphonated
polyaryletherketones, but argues that the “good water management
properties” and the ion transfer function enabled by the sulphonate groups
suffices to motivate the modification of the fuel cells described by Sakai
with the polymers described by Rose. (Ans. 11.) Although Sakai states that
“conventionally utilized” hydrogen conductive PEMs are suitable for the
disclosed fuel cells (Sakai, col. 6, ll. 29-31), the Examiner has not come
forward with credible evidence that the polymers disclosed by Rose would
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have been regarded as conventional PEM materials by those skilled in the
relevant arts at the time the invention was made.
Obviousness cannot be established merely by showing that the critical
material—here, sulphonated polyaryletherketone copolymers—used in a
claimed invention was known prior to the claimed invention. Nor is the
reasonable expectation of success met by a showing that two properties—
here, the ability to form a permeable membrane, and the ability to conduct
hydrogen ions—would have been expected, when the record is silent as to
the reasonable expectations of a critical property—here, water uptake and
membrane stability at high temperatures. Thus, for example, the Examiner
has not come forward with any credible evidence that persons skilled in the
art would have regarded sulphonated polyarylether ketones as equivalents to
Nafion polymers. Alternatively, the Examiner has not explained why the
chemical structure of the polymers disclosed by Rose would have been
expected to provide the well-known chemical, thermal, and mechanical
stability of polytetrafluorethylene-based polymers such as Nafion. Nor has
the Examiner shown that the Rose polymers would have been expected to
exhibit other desired properties, such as appropriate gas permeability.
Absent such a showing, the Examiner has not shown that the sulphonated
polyarylether ketones taught by Rose would have been expected to be
suitable for use in Sakai’s fuel cell. It follows that the Examiner’s
conclusion of obviousness is based on Devine’s own disclosures, and is thus
improper hindsight reconstruction.
Because we conclude the Examiner failed to establish a prima facie
case of obviousness, we need not and do not reach the evidence submitted in
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support of unexpected results. We note, however, that it is improper to
require an applicant to rebut obviousness by presenting a comparison of the
claimed invention against the claimed invention.
D. Order
We REVERSE the rejection of claims 1-13 and 16-19 under
35 U.S.C. § 103(a) in view of the combined teachings of Sakai and Rose.
REVERSED

kmm

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