DETAILED ACTION
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submissions filed on March 16, 2026 and April 9, 2026 have been entered.
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
In the amendment filed on March 18, 2026, claims 1 – 19 are pending. Claims 1, 19 have been amended. Claims 11 – 12 have been withdrawn from consideration.
Claim Analysis
During patent examination, the pending claims must be “given their broadest reasonable interpretation consistent with the specification.” The Federal Circuit' s en banc decision in Phillips v. AWH Corp., 415 F.3d 1303, 75 USPQ2d 1321 (Fed. Cir. 2005). Under a broadest reasonable interpretation (BRI), words of the claim must be given their plain meaning, unless such meaning is inconsistent with the specification. The plain meaning of a term means the ordinary and customary meaning given to the term by those of ordinary skill in the art at the time of the invention. The ordinary and customary meaning of a term may be evidenced by a variety of sources, including the words of the claims themselves, the specification, drawings, and prior art. However, the best source for determining the meaning of a claim term is the specification - the greatest clarity is obtained when the specification serves as a glossary for the claim terms. The words of the claim must be given their plain meaning unless the plain meaning is inconsistent with the specification. In re Zletz, 893 F.2d 319, 321, 13 USPQ2d 1320, 1322 (Fed. Cir. 1989).
However, when an Applicant acts as their own lexicographer and sets forth a special definition that is different from its ordinary and customary meaning(s), the special definition controls the broadest reasonable interpretation of such a defined claim limitation. In re Paulsen, 30 F.3d 1475, 1480, 31 USPQ2d 1671, 1674 (Fed. Cir. 1994).
Such a special definition has been set forth for the term “sintering” on page 14 lines 12 – 21 of the instant specification as quoted:
"Sintering" is intended to mean a heat treatment to a temperature beyond the melting temperature of the polymer present in the MPL layer. This sintering step is generally necessary, for example in the case of the use of PTFE, in order to modify the crystalline structure of the polymer and achieve the desired hydrophobicity of the MPL layer.
Claim Rejections - 35 USC § 103
The rejections of the claims under 35 USC § 103 in the previous Office Action are withdrawn due to Applicant amendment.
Claims 1, 3 –10, 13 – 19 is/are rejected under 35 U.S.C. 103 as being unpatentable over Ariyama JP2017037715 A (formatted machine translation provided and referenced) in view of Daniel et al. “New CCL| MPL Architecture reducing interfacial gaps and enhancing PEM Fuel Cell Performance”. Fuel Cells 20, 2020, No. 2 (of record, hereafter “Daniel”) and Forte et al. WO 2011124850 A1 (description machine translation provided and referenced, hereafter “Forte”); and optionally in view of Daniel et al. “Modified New Microporous Carbon Layer Structure for Improved PEM Fuel Cell Performance with Low-Pt Catalyst Loadings”. Journal of The Electrochemical Society, 2021, 168, 104513 (hereafter “Daniel’2021”).
Regarding claims 1, 3, 5, 7, 8, 9, 10, 16, 18, 19:
Ariyama is directed to a gas diffusion layer (GDL) for a battery membrane, membrane-electrode assembly, battery, and methods of making such components. The battery may be a fuel cell (page 1 lines 19 – 20, page 22 lines 30 – 37, page 23 lines 10 – 20). The membrane electrode-assembly may comprise: a conductive porous substrate of e.g. carbon paper, carbon cloth, metal foam, ect (page 13 line 34 – page 14 line 20); a second hydrophobic conductive porous layer [reading on a conductive microporous layer] laminated onto the conductive porous substrate having a conductive carbon material and a high molecular polymer (page 2 lines 20 – 40, page 8 lines 9 – 17, page 12 lines 35 – 45); a hydrophobic first conductive layer [also can read on a conductive microporous layer (hereinafter “MPL”) ] laminated onto the second conductive layer having a conductive carbon material and a high molecular polymer (page 4 line 5 – page 5 line 20, page 7 lines 20 – 35); and a catalyst layer laminated to the hydrophobic first conductive layer (page 1 lines 20 – 30, page 20 lines 1 – 25, page 3 lines 8 – 20, page 22 lines 1 – 25; Fig. 3 of the original document).
The high molecular weight polymer may singly be PVDF-HFP copolymer – and suggested to be among preferred polymers due to being a fluororesin (page 6 lines 19 – 30, page 7 lines 22 – 30); and the conductive carbon material may be a particulate of e.g. carbon black and/or activated carbon [meeting claim 5] (page 4 lines 25 – 35).
Ariyama discloses that the hydrophobic conductive porous layers may be formed onto the catalyst layer by a method comprising:
preparing by dissolving, mixing and dispersing a suspension [ink] of high molecular polymer and conductive carbon materials in a dispersant [solvent] such as e.g. dimethylacetamide and ethyl acetate wherein the specific dispersant may be used alone [solely] or in combinations (page 7 lines 5 – 15, page 15 lines 4 – 30, page 16 lines 10 – 20, page 16 lines 20 – 26);
coating, spraying or dipping [forming a depositing of an ink] the suspension onto a sheet material (page 16 lines 20 – page 17 line 18);
subsequently drying [evaporating solvent] the suspension on the sheet material to a temperature appropriate for the volatilization temperature of the solvent within the composition to form the hydrophobic conductive porous layer , e.g. a drying temperature between 80°C to 150°C (page 17 lines 20 – 35, page 19 lines 7 – 15, page 29 lines 10 – 20, page 30 lines 10 – 16); and
peeling the sheet from the hydrophobic conductive porous layer and laminating the hydrophobic conductive porous layer onto a cathode catalyst layer (page 30 lines 10 – 16, page 34 lines 9 – 16).
Ariyama does not expressly teach a specific embodiment of their method where the ink comprises the specific recited components; does not expressly teach that the evaporation is carried out by heating to a temperature between 60°C and 80°C; that their method does not include a sintering step; that the deposit of ink is formed at the active layer surface; and that the MPL has a thickness of between 30 µm and 70 µm.
With regards to a specific embodiment of their method where the ink comprises the specific recited components.
Ariyama does disclose the recited solvents, recited binder material and carbonaceous material as suitable for forming the MPL and can be sole components within the suspension ([0050]).
Therefore, it would have been obvious to one of ordinary skill before the effective filing date of the claimed invention to have modified the method of Min by specifically having an ink comprising PVDF-HFP, and one or more of tetrahydrofuran, dimethylacetamide and dimethylforamide alongside the recited carbon-based particulate matter because as taught by Min, the use of such binders and solvents are known to be suitable for the purpose of forming a MPL between GDLs and active/catalyst layers. The courts have held that the selection of a known material/device/product based for its intended use supports a prima facie case of obviousness. Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1945), Ryco, Inc. v. Ag-Bag Corp., 857 F.2d 1418, 8 USPQ2d 1323 (Fed. Cir. 1988).
With regards to the method not including a sintering step:
Ariyama discloses contains a compound using a decomposition temperature of about 80°C or more, particularly at 120 to 250°C. Furthermore, the heating is optional and is “to a higher temperature” with an intention to improve water repellency and the like.
In analogous art, Forte is directed to improvements of fuel cell’s electrochemical converters ([0003] – [0004]). Forte discloses that the electrochemical converters are comprised of metallized porous substrates comprising a hydrophobic coating in at least areas of contact with anodes and/or cathodes of the electrochemical converter ([0009]). The hydrophobic coating is fabricated by a method comprising: providing a porous conductive material such as carbon black, and thermoplastic elastomer polymer such as PVDF-HFP in a solution or emulsion at 80°C ([0021], [0023], [0046], [0050], [0052], [0054], [0137] – [0139]); coating/spraying the polymer-containing solution/emulsion onto the metallized porous substrate at a temperature between 50°C to 80°C ([0046]); removing solvent/ drying the coated metallized porous substrate by ventilating under a fume hood or vacuum-drying ([0143]); and then subjecting the dried coating to a heat treatment/”sintering” at a temperature above the glass transition temperature of the thermoplastic elastomer polymer and closely less than the melting temperature of the polymer, wherein the temperature is preferably between 80°C and 180°C ([0133] – [0134], [0143]). The heat treatment allows for the polymer to uniformly coat the substrates, including substrates with fibers ([0132]). Forte also discloses that the treatment of carbon fiber gas diffusion layers with a solution of polytetrafluoride ethylene (PTFE) is a known conventional treatment, but is prohibited in the context of their invention because such methods require a PTFE sintering at approximately 340°C and a synthetic polymer ([0125] – [0126]). Forte also suggests that the method advantageously provides for a hydrophobic coating at low temperatures below 180°C ([0130]).
Therefore, in view of the prior art as a whole, it would have been obvious to one of ordinary skill before the effective filing date of the claimed invention to have modified the method of Ariyama in view of Daniel to perform the heat treatment at a temperature above the glass transition temperature the PVDF-HFP copolymer within of Ariyama’s ink and slightly/closely below the melting temperature of the PVDF-HFP copolymer because Ariyama teaches that such a treatment can improve the water repellency of the resultant hydrophobic coating, Forte teaches that the treatment aids in uniform coatings of substrates and suggests a desire to maintain process temperatures below 180°C as a way to provide a low temperature process for producing hydrophobic coatings, thus suggesting a desire to exclude heat treatments that are high temperature such as “sintering” treatments as defined by the instant specification.
With regards to evaporation being carried out by heating to a temperature between 60°C and 80°C.
As indicated above, Ariyama discloses that the drying temperature may be between 80°C to 150°C. Additionally as indicated above, Forte discloses that the solution may be applied at a temperature between 50°C to 80°C and dries by exposure to a fume hood. Ariyama and Forte thus encompass at the very least a range touching the claimed range or alternatively overlapping the claimed range.
In the case where the claimed ranges exists where the claimed ranges or amounts do not overlap with the prior art but are merely close, a prima facie case of obviousness exists. Titanium Metals Corp. of America v. Banner, 778 F.2d 775, 783, 227 USPQ 773, 779 (Fed. Cir. 1985). Furthermore, In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art”, a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990); In re Geisler, 116 F.3d 1465, 1469-71, 43 USPQ2d 1362, 1365-66(Fed. Cir. 1997). See MPEP 2144.05.
With regards to the formation of the deposit of ink at the active layer surface:
Daniel is directed to new architectures for fuel cell membrane electrode assemblies and methods of making such membrane electrode assemblies (Abstract). Daniel discloses that their method comprises (Abstract; page 224 2nd column, page 225 “Experimental”): providing a cathode catalyst coated membrane having a cathode catalyst layer (CCL); preparing a MPL ink comprised of polytetrafluoroethylene and carbon black in isopropanol; spraying the MPL ink onto the CCL and heating the MPL alongside the CCL in a muffle furnace for sintering. Daniel discloses that direct coating of the MPL onto the CCL reduces gaps between the MPL and CCL, which affects the ohmic resistance of the MEA, and preserves the kinetic benefits of CCM-based MEAs (page 224, page 227 Conclusions).
Therefore, it would have been obvious to one of ordinary skill before the effective filing date of the claimed invention to have modified the method of Ariyama by spraying/coating the suspension of Ariyama directly onto the catalyst layer and drying the suspension on the catalyst layer because Daniel teaches that the resulting MPL would have less gaps to the catalyst layer and thus reduces the ohmic resistance of the membrane electrode assembly as a whole.
With regards to the MPL having a thickness of between 30 µm and 70 µm:
Ariyama discloses that the thickness of the hydrophobic conductive porous layers may be between about 5 micrometers to 250 micrometers (page 4 lines 14 – 25).
Optionally and additionally, Daniel’2021 is directed to modified new microporous carbon layer structures for proton exchange membranes using MPLs and GDLs (Abstract; page 167). Daniel’2021 discloses that the optimum cathode MPL thickness is dictated by the diffusion length of permeating oxidant gas and the functionality of the layer itself (page 168 1st col 2nd paragraph). While a thinner layer results in a shorter gas diffusion path and thus reducing mass transport resistance, a tinner layer also leads to a higher membrane electrode assembly (MEA) resistance and a reduced back pressure effect; thus in conventional GDLs (page 168 1st col 2nd paragraph). Additionally, Daniel discloses specific examples of their MPL thicknesses, such as an MPL thickness of 0 micrometers to 40 micrometers.
In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art”, a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990); In re Geisler, 116 F.3d 1465, 1469-71, 43 USPQ2d 1362, 1365-66(Fed. Cir. 1997). See MPEP 2144.05.
Optionally and additionally, it would have been obvious to one of ordinary skill before the effective filing date of the claimed invention to have further modified the method of Ariyama in view of Daniel to arrive at a MPL within the claimed thicknesses as a matter of routine experimentation in order to optimize between: mass transport resistance of permeating oxidant gas, and MEA resistance as well as back pressure effect; the thickness of the MPL interacts with such properties in known tradeoffs as discussed in Daniel’2021. "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
Regarding claims 4, 13, 14:
Ariyama discloses that the average particle size of conductive carbon particles may be between e.g. 5nm to 100nm (page 4 lines 35 – 41).
Regarding claim 6:
Ariyama discloses that the mixing ratio of high molecular polymer to conductive carbon material may be 5 – 200 parts by mass to 100 parts by mass, respectively (page 7 lines 40 – 45). Furthermore, the amount of solvent may be between 100 – 1100 parts by mass relative to 100 parts by mass of conductive carbon material (page 16 lines 10 – 20, page 18 lines 30 – 42). The amount of high molecular polymer would then range between about 2% to 50% by weight, the amount of conductive carbon material would range from 7% to 48% by weight, and the amount of solvent may range between 25% to 91%. In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art”, a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990); In re Geisler, 116 F.3d 1465, 1469-71, 43 USPQ2d 1362, 1365-66(Fed. Cir. 1997). See MPEP 2144.05.
Regarding claim 15:
Ariyama discloses overlapping ranges to the claimed average particle size as discussed above. In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art”, a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990); In re Geisler, 116 F.3d 1465, 1469-71, 43 USPQ2d 1362, 1365-66(Fed. Cir. 1997). See MPEP 2144.05.
Regarding claim 17:
The conductive carbon particles may be vapor grown carbon nanofibers (page 5 lines 20 – 30).
Claim 3 is/are rejected under 35 U.S.C. 103 as being unpatentable over Min et al. US 2006/0093892 A1 (hereafter “Min”) in view of Berning US 2008/0113241 A1 (hereafter “Berning”) and Daniel’2021.
Regarding claim 3:
Min is directed to catalysts for fuel cells, fuel cells made and methods of making fuel cells containing such catalysts (Abstract; [0048], [0054], Claims 10, 15). Min discloses that a MPL may be disposed between a catalyst layer and a GDL, wherein the GDL may be e.g. carbon paper or metal cloth ([0049] – [0050]). Min discloses a method of forming a MPL on a catalyst layer comprises ([0050]): preparing a coating composition [ink] of conductive powder (e.g. carbon black), a binder resin ( e.g. polyvinylidenefluoride-hexafluoropropylene [PVdF-HFP]), and a solvent (e.g. tetrahydrofuran, dimethylacetamide, dimethylforamide); and carrying out a coating process [forming a deposit of ink].
While Min does not expressly teach the substrate, Min discloses that the resultant layer is between a GDL and one of a catalyst cathode or anode [active layers], thus suggesting to one of ordinary skill in the art that either layer the GDL or the catalyst cathode/anode may be substrates.
Furthermore, while Min does not expressly teach an embodiment of their method that specifically uses a non-aqueous dispersion specifically comprising the specific binder resin PVDF-HFP, the carbon-based particulate material and the specific recited organic solvents, Min does disclose the recited solvents, recited binder material and carbonaceous material as suitable for forming the MPL ([0050]).
Therefore, it would have been obvious to one of ordinary skill before the effective filing date of the claimed invention to have modified the method of Min by specifically having an ink comprising PVDF-HFP, and one or more of tetrahydrofuran, dimethylacetamide and dimethylforamide alongside the recited carbon-based particulate matter because as taught by Min, the use of such binders and solvents are known to be suitable for the purpose of forming a MPL between GDLs and active/catalyst layers. The courts have held that the selection of a known material/device/product based for its intended use supports a prima facie case of obviousness. Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1945), Ryco, Inc. v. Ag-Bag Corp., 857 F.2d 1418, 8 USPQ2d 1323 (Fed. Cir. 1988).
Min does not expressly teach the step of evaporating the solvent to form the MPL simultaneously/subsequently to the recited step of forming a deposit of an ink; and does not expressly teach that the thickness of the MPL is between 30 micrometers and 70 micrometers, and more particularly 40 micrometers to 60 micrometers.
With regards to the step of evaporating the solvent to form the MPL simultaneously/subsequently to the recited step of forming a deposit of an ink:
Berning is directed to a fuel cell and methods of forming the fuel cell (Abstract; [0001]). Similar to Min, Berning discloses a method of producing a MPL by preparing a dispersion/slurry of particles, binder and solvent; depositing the slurry onto a first catalyst layer [active layer]; and slowly drying the slurry of solvent to form the MPL ([0023], [0026]). The drying is slow in order to ensure a resultant MPL that is free of cracks.
Therefore, it would have been obvious to one of ordinary skill before the effective filing date of the claimed invention to have recognized that the step of evaporating the solvent to form the MPL simultaneously/subsequently to the recited step of forming a deposit of an ink is implied in the method of Min or otherwise have modified the method of Min to have such a step because Berning suggests that drying of the coating composition for forming a MPL is a required step to form the MPL and, alternatively, teaches that slow drying of such inks ensures a dried MPL that is free of cracks.
With regards to the thickness of the MPL being between 30 micrometers and 70 micrometers:
Berning discloses that their disclosed MPL may have a thickness between 30 to 40 micrometers ([0021]).
As discussed above, Daniel’2021 discloses that the optimum cathode MPL thickness is dictated by the diffusion length of permeating oxidant gas and the functionality of the layer itself (page 168 1st col 2nd paragraph). While a thinner layer results in a shorter gas diffusion path and thus reducing mass transport resistance, a tinner layer also leads to a higher membrane electrode assembly (MEA) resistance and a reduced back pressure effect; thus in conventional GDLs (page 168 1st col 2nd paragraph).
Therefore, it would have been obvious to one of ordinary skill before the effective filing date of the claimed invention to have modified the method of Min in view of Berning to arrive at a MPL within the claimed thicknesses as a matter of routine experimentation in order to optimize between: mass transport resistance of permeating oxidant gas, and MEA resistance as well as back pressure effect; the thickness of the MPL interacts with such properties in known tradeoffs as discussed in Daniel’2021. "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
Allowable Subject Matter
Claim 2 is objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
Response to Arguments
Applicant’s arguments, see page 6 – page 7, filed March 16, 2026, with respect to the rejection(s) of the claim(s) under 35 USC 103 over Ariyama in view of Daniel have been fully considered and are persuasive. Therefore, the rejection has been withdrawn. However, upon further consideration, a new ground(s) of rejection is made in view of Forte.
Applicant's arguments filed on March 16, 2026 have been fully considered but they are not fully persuasive.
Applicant’s remaining principal arguments are:
a.) The claimed method overcomes the drawbacks of the method described by Daniel’2021. Daniel describes the use of a PTFE binder and the importance of selecting an appropriate type of carbon in the MPL. Thus in view of Daniel’2021, one of ordinary skill in the art would not arrive to the presently claimed inventions because one of ordinary skill in the art would consider acetylene black rather than “VC” as used in the present application and would have targeted an MPL thickness of around 20 µm rather than a thickness between 30 and 70 µm.
c.) Present claim 3 is distinguished over Min in view of Berning and Daniel’2021 because claim 3 is distinguished over Daniel’2021 as discussed concerning argument
In response to the applicant's arguments, please consider the following comments.
a.) As a first matter, Daniel’2021 is applied optionally to the rejection under Ariyama in view of the cited secondary references. The rejection of the claims is satisfied by Ariyama’s teachings in view of the cited secondary references.
As a second matter, the claims require that the dispersion comprises a carbon-based particle. Applicant’s argument concerning “VC” is therefore not commensurate in scope with the claimed carbon-based particulate material with respect to teaching away from the particular material choice. Applicant fails to relate how the specific choice of VC would lead away from a prima facie case of obviousness.
b.) The lack of commensurate scope discussed above in argument a.) above also apply to the response to Applicant’s argument, mutatis mutandis.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. T Lestariningsih et al. “Structure, thermal and electrical properties of PVDF-HFP/LiBOB solid polymer electrolyte”. 2019 J. Phys.: Conf. Ser. 1191 012026.; particularly table 2 describing a select range of melting points for PVDF-HFP polymers in the recited environments.
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/JOSE I HERNANDEZ-KENNEY/
Primary Examiner
Art Unit 1717
Prosecution Insights