Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Continued Examination Under 37 CFR 1.114
The amendment filed April 24, 2026 has been received and entered. With the entry of the amendment, claims 2, 4, 9-10, 16 and 18 are canceled, claims 13-15 are withdrawn and claims 1, 3, 5-8, 11-12 and 17 are pending for examination.
Election/Restrictions
Applicant’s election without traverse of Group I, claims 1-12, in the reply filed on March 18, 2024 is acknowledged.
Claims 13-15 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention, there being no allowable generic or linking claim. Election was made without traverse in the reply filed on March 18, 2024.
Claim Rejections - 35 USC § 112
The rejection of claim 18 under 35 U.S.C. 112(d) or pre-AIA 35 U.S.C. 112, 4th paragraph, as being of improper dependent form for failing to further limit the subject matter of the claim upon which it depends, or for failing to include all the limitations of the claim upon which it depends is withdrawn due to the cancellation of claim 18.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1, 3, 5 and 17 are rejected under 35 U.S.C. 103 as being unpatentable over Li, et al “A low cost shutdown sandwich-like composite membrane with superior thermo-stability for lithium-ion battery” (hereinafter Li article) in view of KR 20220146891 (hereinafter ‘891), Gubler, et al “Composite Membranes Containing a Porous Separator and a Polybenzimidazole Thin Film for Vanadium Redox Flow Batteries” (hereinafter Gubler article), CN 111205465 (hereinafter ‘465) and Staiti, et al “Sulfonated polybenzimidazole membranes – preparation and physico-chemical characterization” (hereinafter Staiti article), and further as evidenced by KR 101952923 (hereinafter ‘923).
Claims 1, 17: Li article teaches a method for manufacturing a polybenzimidazole (PBI)-based separator (note abstract, section 2.2, combined separator and membrane can be considered a resulting separator, Scheme 1, and considered PBI based due to the PBI coating). The method comprises dissolving a PBI-based compound in a dimethyl acetamide solvent (N,N-dimethylacetamide, DMAC) to produce a PBI solution (section 2.2, and note section 1 indicating PBI as polybenzimidazole). A porous membrane (PE separator) was impregnated with the PBI solution (immersed in solution where PBI diffuses through the pores of the PE separator and precipitated on pore walls of the separator, and therefore is impregnated) (note section 2.2, Scheme 1 and section 3, page 4, column 1). The impregnated porous membrane is dried at a temperature of 70 degrees C (less than 80 degrees C) to obtain the PBI based separator (section 2.2). In Li article, the porous membrane is made of polyethylene (PE) (note section 2.2, and section 1 describing PE as polyethylene). In Li article, no backing (removable) substrate is used (note Scheme 1 and section 2.2).
(A) As to the use of the manufactured separator for a secondary battery as claimed (redox battery using oxidation and reduction reaction of a vanadium redox couple and sulfuric acid electrolyte), Li article describes that a separator membrane is formed (abstract) and describes its use for lithium ion batteries (abstract).
‘891 further describes the use of a PBI based membrane for use in a redox flow battery (secondary battery), where the battery can be a redox battery using oxidation and reduction reactions of a vanadium redox couple and acid electrolyte, where the acid electrolyte can be sulfuric acid(note pages 2, 3, translation), where the PBI based membrane (which has been manufactured, where the membrane can have additional porous polymer used) is provided and treated with sulfuric acid, and then used in the battery (since a battery is provided with this separator) (note page 3, translation).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Li article to further use the manufactured separator for a secondary battery including a redox battery as claimed as suggested by ‘891 with an expectation of providing a further desirable use for the separator, since Li article makes a PBI based separator for use in batteries, and ‘891 indicates how a further use of for a PBI based separator is for use in secondary batteries including a redox battery using oxidation and reduction reactions of a vanadium redox couple and sulfuric acid electrolyte.
(B) Further as to the specific use of the PBI based compound of m-PBI, ‘891 notes m-PBI can be used for the membrane (page 3, translation).
Gubler article describes how mPBI (meta-polybenzimidazole) can be used as a PBI material for membrane separators for vanadium redox flow batteries (note abstract, first column of Experimental Section, Conclusions section). Gubler article also notes using sulfuric acid electrolyte (note second column of the first page, Experimental Section-Oxidative Stability section).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Li article in view of ‘891 to use mPBI as the specific PBI compound to use as suggested by Gubler article with an expectation of predictably acceptable results, since Li article uses a PBI compound for the separator, ‘891 suggests the use of the PBI compound for forming a PBI based separator for use in vanadium redox batteries and notes using m-PBI, and Gubler article indicates that an acceptable PBI based compound to use for separators for vanadium redox batteries would be mPBI, giving a suggested PBI compound for using in the process of Li article as well, and further also notes using sulfuric acid electrolyte with the vanadium redox batteries.
(C) Further as to providing that the dissolving occurs under a temperature in the range of 130-160 degrees C (claim 1) or 140-160 degrees C (claim 17), and the maximum solubility is 8-12 wt% (claim 1), Li article notes dissolving the PBI compound in DMAC making a 4 wt% solution (note section 2.2). Gubler article further describes how when using mPBI for vanadium redox batteries the mPBI can be provided as a 10 wt% solution in DMAC (10 % by weight mPBI, from 25 g mPBI and 225 g DMAC), where the temperature of dissolving is described at 60 degrees C (note Experimental section, first and second columns).
‘465 further describes that mPBI can be provided in an approx. 10.7 wt% solution of DMAC (1 g of mPBI and 10 ml of DMAC, where the Examiner takes Official Notice that DMAC conventionally has a density of about 9.37 g/ml, giving 9.37 g of DMAC from 10 ml) by adding the mPBI to the solvent and heating at 110-140 degrees C to completely dissolve (note translation, page 4).
Staiti article describes how PBI compounds can be formed into membranes that are further treated (note sections 2.1 to 2.2). Staiti article indicates to solubilize (dissolve) in DMAC at 150 degrees C for a period of time to provide a solution with 12.5 wt% PBI for use in the membrane forming (note section 2.1).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Li article in view of ‘891 and Gubler article to dissolve the PBI compound in the DMAC solvent at a temperature of 140 degrees or 150 degrees C, for example (in the ranges of claims 1, 17), and in an amount within the range of 10-12 wt%, for example, as maximum solubility (in the ranges of claim 1) as suggested by Gubler article, ‘465 and Staiti article with an expectation of predictably acceptable results, since Li article uses PBI compound dissolved in a solution of DMAC, where the use of m-PBI is suggested by Gubler article, and it is indicated from Gubler article that the temperature for dissolving such mPBI in DMAC can be 60 degrees C for a 10 wt% solution of mPBI, ‘465 describes complete dissolving of a similar amount of mPBI in DMAC can be at 110-140 degrees C, and Staiti article indicates how PBIs in general can be dissolved at a temperature of 150 degrees C, and one of ordinary skill in the art would optimize the amount of PBI compound used, from the options given, giving a value in the claimed range, with the adjustment of the amount allowing more or less PBI compound to be provided in a relative amount of solution for use, and as well would be suggested to use an amount within 10-12 wt% mPBI as an amount suggested specifically for mPBI for battery separators and to provide this as maximum solubility as providing the amount of material desired; and one would also optimize the temperature used from the possible values and ranges given, giving a temperature in the claimed range. Also note MPEP 2144.05(II)(A): “Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. "[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) “.
(D) further as to the manufactured PBI based separator provides ion exchange of hydrogen ions, ‘891 indicates how the PBI based separator can be provided to be ion conductive/selective through doping the membrane with sulfuric acid (note page 2, translation).
Additionally, ‘923 would evidence that a PBI membrane is known to have hydrogen ion transporting ability (where such membrane use also described as ion exchange membranes) by supporting an acid such as sulfuric acid, where the electrolytic solution for a vanadium redox battery contains sulfuric acid, such that the PBI polymer has the possibility of being applied to the vanadium flow battery (note page 2, translation).
Therefore, it would have been understood that when providing the process of Li article in view of ‘891, Gubler article, ‘465 and Staiti article, that the separator would provide ion conductivity/ion exchange of hydrogen ions as evidenced from the teaching of ‘465 and ‘923 as discussed above.
Claim 3: in Li article, both opposing surfaces are impregnated, due to the immersion in the solution (Scheme 1, section 2.2, and note the impregnating from the immersion as discussed for claim 1 above).
Claim 5: in Li article the thickness of the porous membrane (PE separator) is 20 microns (note section 2.2, Table 2, and also section 3, page 4, column 1, where each PBI layer is 4 microns, and total membrane thickness 28 microns (Table 2, section 2.2), so leaving 20 microns for the membrane), in the claimed range, and the thickness of formed separator is 28 microns (section 2.2, in the claimed range).
Claims 6-8 are rejected under 35 U.S.C. 103 as being unpatentable over Li article in view of ‘891, Gubler article, ‘465 and Staiti article, and as evidenced by ‘923 as applied to claims 1, 3, 5 and 17 above, and further in view of Livingston et al (US 2013/0118983).
Claims 6-8: As to the use of a surfactant, and its amount and type,
Livingston further describes how membranes can be made (note 0001), where PBI based solutions can be used, where the PBI solutions are made with PBI polymer and solvent, such as N,N-dimethylacetamide (DMAc) and N, N-dimethylformamide, etc. (note 0040-0046, 0048, 0088). Livingston notes mPBI (note the formula shown) is a preferred PBI to use (note 0037). It is described that when providing solutions, additionally a surfactant can be present, which help influence the resulting pore structure, where the surfactant can be provided in an amount of up to 5 wt% of the solution and can be TRITON X-100 (oxylphenoxy-poly-ethoxyethanol) (note 0045, 0050).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Li article in view of ‘891, Gubler article, ‘465 and Staiti article, and as evidenced by ‘923 to provide the solution also includes surfactant such as TRITON X-100 as suggested by Livingston to help control pore structure, as Li article provides how a PBI based separator can be provided by immersing a membrane material in PBI based solution giving a porous structure and notes pores for ion conductivity in the PBI layer (page 4, column 1), Gubler article suggests using mPBI, and Livingston indicates that when using PBI (which can include mPBI) solutions with amide based organic solvent, adding surfactant to the solution can also be used to help control resulting pore structure of the formed material. It would be understood that the provided surfactant would also dissolve in the solution as the same surfactant used by applicant (note TRITON X-100 also listed by applicant 00117 of the specification) and the same solvents used by applicant are used (note DMAc, with DMAc described by applicant, 00129 of the specification). For claim 7, Livingston would suggest using up to 5 wt% of the solution, overlapping the claimed range. It would have been obvious to optimize from within the taught range, giving a value in the claimed range. Note that 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, 191 USPQ 90 (CCPA 1976). For claim 8, Livingston suggests TRITON X-100, where this is described as an organic material (so organic surfactant), and as well applicant identifies this also as a non-ionic surfactant (00117 of the specification).
Claims 11 and 12 are rejected under 35 U.S.C. 103 as being unpatentable over Li article in view of ‘891, Gubler article, ‘465, Staiti article and Livingston, and as evidenced by ‘923, as applied to claims 6-8 above, and further in view of Cabasso et al (US 2004/0028976).
Claims 11-12: As to use of a viscosity control solvent and its amount and material,
Livingston further notes that solvents which can be used for dissolving the PBI compound can be DMAc, etc. but also can be mixtures that also include alcohols (note 0048). Livingston also notes that viscosity adjusters (enhancers) can be used, describing amounts of up to 10 wt% in the solution, but does not specifically provide using solvents for this purpose (note 0050).
Cabasso describes providing PBI compounds and dissolving in solvents such as N, N-dimethylacetamide (DMAc), etc. (0040) where it is also described how solvents that can dissolve can be DMAc and also lower alcohols such as methanol, ethanol and isopropanol (note 0051). The PBI compound can be mPBI (note 0011 formula).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Li article in view of ‘891, Gubler article, ‘465, Staiti article and Livingston, and as evidenced by ‘923 to dissolve the PBI compound using a mixture of DMAc (amide solvent) and also alcohols such as methanol, ethanol, and isopropanol as suggested by Livingston and Cabasso with an expectation of predictably acceptable results, as Li article provides how a PBI solution can be provided by dissolving a PBI based compound and solvent such as DMAC/DMAc, Gubler articles indicates using mPBI and also dissolving in DMAC, and Livingston indicates that for dissolving such compounds one can use DMAC/DMAc and also alcohols in a mixture and Cabasso indicates that when dissolving PBI compound (including mPBI), DMAc, and alcohols such as methanol, ethanol and isopropanol can be used. By using the additional ethanol, methanol or isopropanol, a viscosity control solvent as in claims 11 and 12 would be used. As to the amount of the viscosity control solvent, it would have been obvious to optimize the specific amount of each solvent used, giving an amount in the claimed range. Note MPEP 2144.05(II)(A): “Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. "[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) “.
Claims 1, 3 and 17 are rejected under 35 U.S.C. 103 as being unpatentable over Verzwyvelt (US 4217404) in view of KR 20220146891 (hereinafter ‘891), Gubler, et al “Composite Membranes Containing a Porous Separator and a Polybenzimidazole Thin Film for Vanadium Redox Flow Batteries” (hereinafter Gubler article), CN 111205465 (hereinafter ‘465) and Staiti, et al “Sulfonated polybenzimidazole membranes – preparation and physico-chemical characterization” (hereinafter Staiti article), and further as evidenced by KR 101952923 (hereinafter ‘923).
Claims 1, 17: Verzwyvelt teaches a method for manufacturing a polybenzimidazole (PBI)-based separator (note separator saturated/coated with PBI, so considered PBI based, note column 1, line 60 to column 2, line 20). The method comprises dissolving a PBI-based compound in an dimethyl acetamide solvent (such dimethylacetamide, DMA (or could also be called DMAC)) to produce a PBI solution (note column 2, lines 45-55, column 3, lines 15-30, for example). A porous membrane (note column 3, lines 20-35 and 50-60, column 3, line 65 to column 4, line 10) was impregnated with the PBI solution (immersed in solution, or vacuum backfilled, for example, where the solution will enter the pores/openings of membrane and coat/impregnate) (note column 3, line 15 to column 4, line 15, and note the described impregnation in claim 1). The impregnated porous membrane is dried at a temperature of not exceeding 100 degrees C (note column 2, lines 15-20), so giving a range of up to 100 degree C overlapping the claimed range. It would have been obvious to optimize from within the taught range, giving a value in the claimed range. Note that 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, 191 USPQ 90 (CCPA 1976). While applicant has one example with a drying temperature higher than 80 degrees C giving shrinkage, this example uses a specific PBI amount, application type, solution, etc. and a showing is not made commensurate in scope with the entire claims, so no criticality has been shown. In Verzwyvelt, the porous membrane can be made of polypropylene or polyethylene (note column 1, lines 65-68, column 3, lines 15-65). In Verzwyvelt, no backing (removable) substrate is needed to be used to form the separator (note the examples of column 3, line 15 to column 4, line 15).
(A) As to the use of the manufactured separator for a secondary battery (of a redox battery using oxidation and reduction reaction of a vanadium redox couple and sulfuric acid electrolyte) as claimed, Verzwyvelt describes that a separator is formed (abstract) and describes its use for alkaline storage batteries (column 1, lines 20-25), where what can be considered a membrane is formed (note column 3, line 65 to column 4, line 15 with an impregnated membrane).
‘891 further describes the use of a PBI based membrane for use in a redox flow battery (secondary battery), where the battery can be a redox battery using oxidation and reduction reactions of a vanadium redox couple and acid electrolyte, where the acid electrolyte can be sulfuric acid(note pages 2, 3, translation), where the PBI based membrane (which has been manufactured, where the membrane can have additional porous polymer used) is provided and treated with sulfuric acid, and then used in the battery (since a battery is provided with this separator) (note page 3, translation).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Verzwyvelt to further use the manufactured separator for a secondary battery including a redox battery as claimed as suggested by ‘891 with an expectation of providing a further desirable use for the separator, since Verzwyvelt makes a PBI based separator for use in batteries, and ‘891 indicates how a further use of for a PBI based separator is for use in secondary batteries including a redox battery using oxidation and reduction reactions of a vanadium redox couple and sulfuric acid electrolyte.
(B) As to the specific PBI compound used, Verzwyvelt describes using PBI (note Example 1). ‘891 notes m-PBI can be used for the membrane (page 3, translation).
Gubler article describes how mPBI (meta-polybenzimidazole) can be used as a PBI material for membrane separators for vanadium redox flow batteries (note abstract, first column of Experimental Section, Conclusions section). Gubler article also notes using sulfuric acid electrolyte (note second column of the first page, Experimental Section-Oxidative Stability section).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Verzwyvelt in view of ‘891 to use mPBI as the specific PBI compound to use as suggested by Gubler article with an expectation of predictably acceptable results, since Verzwyvelt uses a PBI compound for the separator, ‘891 suggests the use of the PBI compound for forming a PBI based separator for use in vanadium redox batteries and notes using m-PBI, and Gubler article indicates that an acceptable PBI based compound to use for separators for vanadium redox batteries would be mPBI, giving a suggested PBI compound for using in the process of Verzwyvelt as well, and further also notes using sulfuric acid electrolyte with the vanadium redox batteries.
(C) As to further as to providing that the dissolving occurs under a temperature in the range of 130-160 degrees C (claim 1) or 140-160 degrees C (claim 17), and the maximum solubility is 8-12 wt% (claim 1), Verzwyvelt describes that PBI can be used in a solution of 5% w/v PBI in DMAC, for example (note column 3, lines 45-50). Gubler article further describes how when using mPBI for vanadium redox batteries the mPBI can be provided as a 10 wt% solution in DMAC (10 % by weight mPBI, from 25 g mPBI and 225 g DMAC), where the temperature of dissolving is described at 60 degrees C (note Experimental section, first and second columns).
‘465 further describes that mPBI can be provided in an approx. 10.7 wt% solution of DMAC (1 g of mPBI and 10 ml of DMAC, where the Examiner takes Official Notice that DMAC conventionally has a density of about 9.37 g/ml, giving 9.37 g of DMAC from 10 ml) by adding the mPBI to the solvent and heating at 110-140 degrees C to completely dissolve (note translation, page 4).
Staiti article describes how PBI compounds can be formed into membranes that are further treated (note sections 2.1 to 2.2). Staiti article indicates to solubilize (dissolve) in DMAC at 150 degrees C for a period of time to provide a solution with 12.5 wt% PBI for use in the membrane forming (note section 2.1).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Verzwyvelt in view of ‘891 and Gubler article to dissolve the PBI compound in the DMAC solvent at a temperature of 140 degrees or 150 degrees C, for example (in the ranges of claims 1, 17), and in an amount within the range of 10-12 wt% as maximum solubility (in the ranges of claims 1, 18) as suggested by Gubler article, ‘465 and Staiti article with an expectation of predictably acceptable results, since Verzwyvelt uses PBI compound dissolved in a solution of DMAC, where the use of m-PBI is suggested by Gubler article, and it is indicated from Gubler article that the temperature for dissolving such mPBI in DMAC can be 60 degrees C for a 10 wt% solution of mPBI, ‘465 describes complete dissolving of a similar amount of mPBI in DMAC can be at 110-140 degrees C, and Staiti article indicates how PBIs in general can be dissolved at a temperature of 150 degrees C, and one of ordinary skill in the art would optimize the amount of PBI compound used, from the options given, giving a value in the claimed range, with the adjustment of the amount allowing more or less PBI compound to be provided in a relative amount of solution for use, and as well would be suggested to use an amount within 10-12 wt% mPBI as an amount suggested specifically for mPBI for battery separators and to provide this as maximum solubility as providing the amount of material desired; and one would also optimize the temperature used from the possible values and ranges given, giving a temperature in the claimed range. Also note MPEP 2144.05(II)(A): “Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. "[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) “.
(D) further as to the manufactured PBI based separator provides ion exchange of hydrogen ions, ‘891 indicates how the PBI based separator can be provided to be ion conductive/selective through doping the membrane with sulfuric acid (note page 2, translation).
Additionally, ‘923 would evidence that a PBI membrane is known to have hydrogen ion transporting ability (where such membrane use also described as ion exchange membranes) by supporting an acid such as sulfuric acid, where the electrolytic solution for a vanadium redox battery contains sulfuric acid, such that the PBI polymer has the possibility of being applied to the vanadium flow battery (note page 2, translation).
Therefore, it would have been understood that when providing the process of Verzwyvelt in view of ‘891, Gubler article, ‘465 and Staiti article, that the separator would provide ion conductivity/ion exchange of hydrogen ions as evidenced from the teaching of ‘465 and ‘923 as discussed above.
Claim 3: In Verzwyvelt, both surfaces of the membrane can be impregnated (such as by immersing), for example (note column 3, lines 15-65, claim 1).
Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over Verzwyvelt in view of ‘891, Gubler article, ‘465 and Staiti article, and as evidenced by ‘923 as applied to claims 1, 3 and 17 above, and further in view of Li, et al “A low cost shutdown sandwich-like composite membrane with superior thermo-stability for lithium-ion battery” (hereinafter Li article).
Claim 5: As to the specific thickness of the porous membrane and the resulting PBI based separator,
Li article teaches a method for manufacturing a polybenzimidazole (PBI)-based separator (note abstract, section 2.2, combined separator and membrane can be considered a resulting separator, Scheme 1, and considered PBI based due to the PBI coating). The method comprises dissolving a PBI-based compound in an amide based organic solvent (N,N-dimethylacetamide, DMAC) to produce a PBI solution (section 2.2, and note section 1 indicating PBI as polybenzimidazole). A porous membrane (PE separator) was impregnated with the PBI solution (immersed in solution where PBI diffuses through the pores of the PE separator and precipitated on pore walls of the separator, and therefore is impregnated) (note section 2.2, Scheme 1 and section 3, page 4, column 1). The impregnated porous membrane is dried at a temperature of 70 degrees C (less than 80 degrees C) to obtain the PBI based separator (section 2.2). Furthermore, in Li article the thickness of the porous membrane (PE separator) is 20 microns (note section 2.2, Table 2, and also section 3, page 4, column 1, where each PBI layer is 4 microns, and total membrane thickness 28 microns (Table 2, section 2.2), so leaving 20 microns for the membrane), in the claimed range, and the thickness of formed separator is 28 microns (section 2.2, in the claimed range).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Verzwyvelt in view of ‘891, Gubler article, ‘465 and Staiti article, and as evidenced by ‘923 to provide the membrane thickness of 20 microns and the PBI based separator thickness of 28 microns as suggested by Li article as giving a predictably acceptable membrane and PBI based separator thickness to provide, since Verzwyvelt provides how a PBI based separator can be provided by immersing a membrane material in PBI based solution, and Li article indicate how in a similar process as described above, the membrane thickness can be 20 microns and the PBI based separator thickness 28 microns, both in the claimed range.
Claims 6-8 are rejected under 35 U.S.C. 103 as being unpatentable over Verzwyvelt in view of ‘891, Gubler article, ‘465 and Staiti article, and as evidenced by ‘923 as applied to claims 1, 3 and 17 above, and further in view of Livingston et al (US 2013/0118983).
Claims 6-8: As to the use of a surfactant, and its amount and type,
Livingston further describes how membranes can be made (note 0001), where PBI based solutions can be used, where the PBI solutions are made with PBI polymer and solvent, such as N,N-dimethylacetamide (DMAc) and N, N-dimethylformamide, etc. (note 0040-0046, 0048, 0088). The PBI polymer can be preferably mPBI (note the formula in 0037). It is described that when providing solutions, additionally a surfactant can be present, which help influence the resulting pore structure, where the surfactant can be provided in an amount of up to 5 wt% of the solution and can be TRITON X-100 (oxylphenoxy-poly-ethoxyethanol) (note 0045, 0050).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Verzwyvelt in view of ‘891, Gubler article, ‘465 and Staiti article, and as evidenced by ‘923 to provide the solution also includes surfactant such as TRITON X-100 as suggested by Livingston to help control pore structure, as Verzwyvelt provides how a PBI based separator can be provided by immersing a membrane material in PBI based solution giving a porous structure and notes control of gas permeability (porous structure formation) based on coating conditions (note column 3, lines 1-15), Gubler article suggests using mPBI, and Livingston indicates that when using PBI solutions with amide based organic solvent (including where the PBI can be mPBI and the solvent DMAC), adding surfactant to the solution can also be used to help control resulting pore structure of the formed material. It would be understood that the provided surfactant would also dissolve in the solution as the same surfactant used by applicant (note TRITON X-100 also listed by applicant 00117 of the specification) and the same solvents used by applicant are used (note DMAc, with DMAc described by applicant, 00129 of the specification). For claim 7, Livingston would suggest using up to 5 wt% of the solution, overlapping the claimed range. It would have been obvious to optimize from within the taught range, giving a value in the claimed range. Note that 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, 191 USPQ 90 (CCPA 1976). For claim 8, Livingston suggests TRITON X-100, where this is described as an organic material (so organic surfactant), and as well applicant identifies this also as a non-ionic surfactant (00117 of the specification).
Claims 11 and 12 are rejected under 35 U.S.C. 103 as being unpatentable over Verzwyvelt in view of ‘891, Gubler article, ‘465, Staiti article and Livingston, and as evidenced by ‘923 as applied to claims 6-8 above, and further in view of Cabasso et al (US 2004/0028976).
Claim 11-12: As to use of a viscosity control solvent and its amount and material,
Livingston further notes that solvents which can be used for dissolving the PBI compound can be DMAc, etc. but also can be mixtures that also include alcohols (note 0048). Livingston also notes that viscosity adjusters (enhancers) can be used, describing amounts of up to 10 wt% in the solution, but does not specifically provide using solvents for this purpose (note 0050).
Cabasso describes providing PBI compounds and dissolving in solvents such as N, N-dimethylacetamide (DMAc), etc. (0040) where it is also described how solvents that can dissolve can be DMAc and also lower alcohols such as methanol, ethanol and isopropanol (note 0051). The PBI compound can be mPBI (note 0011 formula).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Verzwyvelt in view of ‘891, Gubler article, ‘465, Staiti article and Livingston, and as evidenced by ‘923 to dissolve the PBI compound using a mixture of DMAc (amide solvent) and also alcohols such as methanol, ethanol, and isopropanol as suggested by Livingston and Cabasso with an expectation of predictably acceptable results, as Verzwyvelt provides how a PBI solution can be provided by dissolving a PBI based compound and solvent such as DMA/DMAc, Gubler article suggests to use mPBI, and Livingston indicates that for dissolving such compounds one can use DMA/DMAc and also alcohols in a mixture and Cabasso indicates that when dissolving PBI compound DMAc, and alcohols such as methanol, ethanol and isopropanol can be used. By using the additional ethanol, methanol or isopropanol, a viscosity control solvent as in claims 11 and 12 would be used. As to the amount of the viscosity control solvent, it would have been obvious to optimize the specific amount of each solvent used, giving an amount in the claimed range. Note MPEP 2144.05(II)(A): “Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. "[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
The Examiner notes that the rejections above use the suggestion to optimize various amounts and values. In the specification as filed an Example and comparative Examples were provided, and in the declaration filed August 4, 2025, further examples and arguments as to criticality were provided. The Examiner has reviewed this, however, a showing of criticality commensurate in scope to what is claimed has not been made. Note MPEP 716.02(d). For example, (1) as to the drying temperature, when using Verzwyvelt, while applicant has one example with a drying temperature higher than 80 degrees C giving shrinkage, this example uses a specific amount, application type, solution, etc. and a showing is not made commensurate in scope with the entire claims, which could use different amounts, application type, and additional compounds such as surfactants and viscosity control solvents added, etc. (which changes would be expected to affect results, such as, for example, different solvents can have different solubility effects, etc.), so no criticality commensurate in scope with what is claimed has been shown. The August 2025 declaration does not provide further showings as to the drying temperature. (2) Furthermore as to the declaration of August 2025, it does not establish criticality commensurate in scope over the width of the claims. All of the tests appear to be using simply m-PBI in DMAC where the present claims allow additional material (such as viscosity control solvent and surfactant, note claim 6, 11, for example, which would change the composition and could affect results, as noted above), where the solution is at normal pressure (noting that the present claims would allow any pressure, where even with the pressure range deleted in claim 1, there is no limit on pressure), for example. It is not shown why the results applicant got with the specific m-PBI solution used would work with all possible solutions as claimed, where the previously used Tan reference, for example, would show that higher temperatures can be used in combination with higher pressures, for example, so evidencing against this. As well, note Livingston at 0088, Table 2, with DMAC, with high weight % of PBI at 80 degrees C. Additionally, the references to Gubler article and ‘465 appear to contradict the results shown in applicant’s declaration, where Gubler article indicates providing 10 wt% mPBI (in the claimed range) in DMAC at a dissolving temperature of 60 degrees C (so results as desired outside the claimed temperature range), and ‘465 indicates approx. 10.7 wt% mPBI (in the claimed range) completely dissolved at temperatures in the range of 110-140 degrees C (so results as desired in and out of the claimed temperature range). Thus, the evidence of record does not support that there is criticality as to the claimed temperature range to get the claimed amount of mPBI in solution. This also shows that it is well known to achieve amounts of mPBI in DMAC solvent in the claimed ranges, and Gubler article would show the known use of this amount in the separator art. Additionally, Staiti article indicates using a temperature in the claimed range to give solubility it the range of 8-20 wt% described in paragraphs 23-29 is in fact known. (3) Furthermore, all testing is done as noted for a solution of mPBI and DMAC, and also not indicated what effects occur when other allowed materials present, such as in claim 6, 8 and 11, for example, where effects of surfactant and viscosity control solvent would need to be taken into account. Thus, the testing is not commensurate in scope with the range of materials claimed. A showing of criticality would therefore, not have been made.
Hwang, et al “Preparation of Polybenzimidazole-Based Membranes and Their Potential Applications in the Fuel Cell System”, describes the formulas of various PBI compounds, including oPBI (which corresponds that that described in Yuan article) (note schemes 3, 4, 5). “Technical Data Sheet Dimethylacetamide (DMAc)” notes the boiling point of DMAc as 166 degrees C (note page 1). Lu et al (US 2023/0275247) notes redox flow batteries (note 0001), which can use vanadium redox couple (note 0006, 0020), where a separator can be used which is a PBI based membrane (note 0013).
Response to Arguments
Applicant's arguments filed April 24, 2026 have been fully considered.
Note the adjustment to the rejections, with the new evidentiary reference to ‘923 due to the amendments to the claims.
As to the arguments as to the previous 35 USC 103 rejections, firstly, as to the now claimed “a backing substrate is not used to form the polybenzimidazole separator”, it is argued that the primary references would not provide this, where Li article has water immersion and Verzwyvelt has blotting that are required steps. It is argued that the “without using a backing substrate” does not mean merely the absence of a removable temporary support, but rather refers to a direct manufacturing process where the porous membrane is directly impregnated with PBI solution and dried to form the separeator without any separate release, transfer, peel-off, water immersion step or blotting, with no backing substrate used in the entire process, citing paragraphs 0105-0107 of the specification (note pages 11-12 of the amendment). Secondly, it is argued that Li article and Verzwyvelt are directed to different battery types and different required separator performances, so there would not be a motivation to use a vanadium redox flow battery (VRFB), as claimed, and which has hydrogen ion exchange. It is argued that Li article and Verzwyvelt do not select the PBI for exchange functionality, etc. and the batteries noted to be porous, while the method of claim 1 provides for a dense separator, and so the method manufactures something different from the primary references. It is argued that if a porous structure formed, allowing transfer of active material, problems of cross-over, short circuiting will occur. It is further argued that the cited ‘891 describes use of PBI in a VRFB, but has predoping and equilibrating, which is different than that claimed, and as to Gubler article forms a layer on glass not directly on a porous substrate, which is a different process than that claimed. Thirdly, as to the use of ‘465, it is argued that this merely relates to dissolution conditions, and does not disclose a process of forming the separator without a backing layer or water immersion process. As to Staiti article, it is argued that it further does not describe formation on a prous membrane, or manufacture of a sulfuric acid undoped PBI separator, without backing substrate, water immersion or blotting step.
The Examiner has reviewed these arguments, however, the rejections above are maintained. Firstly, as to the now claimed “a backing substrate is not used to form the polybenzimidazole separator” neither Li article or Verzwyvelt requires a removable backing layer (where Li article immerses a porous membrane to impregnate and dries without any removable backing layer (note section 2.2, Scheme 1)). Similarly, Verzwyvelt provides a porous membrane, impregnates with PBI solution and dries (as discussed in the rejection above) without any removable backing layer. As to Li article having a water immersion step and Verzwyvelt having a blotting step, there is nothing preventing such steps in the present claims, or in the disclosure as filed (note for example, the comprising language as to the steps in claim 1). Applicant’s attorney argues that “without using a backing layer” would mean there is no separate release, transfer, peel-off, water immersion step or blotting. The Examiner disagrees. The cited paragraphs 0105-0107, for example, do not support this, but rather refer to not using a backing substate where the PBI is applied to form a film and peeled off. This has no mention or discussion of an entirely different process of water immersion or blotting. Note also 0108 of the specification which indicates that by performing the claimed process “Thus, the porous membrane does not have to be removed from the backing substrate separately”, again simply referring to a substrate that is later removed.
Secondly, as to Li article and Verzwyvelt being directed to different battery types and different required separator performances, so there would not be a motivation to use a vanadium redox flow battery (VRFB), as claimed, and the claimed separator having hydrogen ion exchange, the Examiner is of the position that while Li article and Verzwyvelt do not describe using the separator for VRFB, both Li article and Verzwyvelt describe how PBI separators can be formed to be used in batteries. ‘891 has been cited as to how it is well known that separator/membrane material formed from PBI material can be provided and supported by a porous polymer layer can be used for VRFB batteries as well, where for use the membrane is further treated with sulfuric acid, which is not prevented by the present claims. Thus, Li article and Verzwyvelt are at least reasonably pertinent to the problem faced by the inventor of providing a desirable PBI separator, where ‘891 shows that it is conventionally known in the art to use such separator/membrane material for VRFB as well as other types of batteries, for example. It can even be considered that the references are in the same field of endeavor, as directed to separators for batteries. As to the hydrogen exchange functionality, ‘891 as now discussed in the rejection above, shows how the formed membranes can be provided with ion exchange functionality, and the new evidentiary reference to ‘923 would further indicate that for PBI membranes such ion exchange functionality would be to allow hydrogen ion exchange when used for the VRFB. Thus, again it is suggested from ‘891 and as evidenced by ‘923 that the separator process described by Li article and Verzwyvelt can be used for making membrane separators used in VRFB processes and would have hydrogen ion exchange functionality. ‘891 would further indicate the use with a sulfuric acid electrolyte. As to porosity being maintained by water immersion or blotting, so would not apply to the ion exchange, noting applicant’s reference to page 5 of Li article, while this refers to porosity being present, it also notes favorable effects on ion conduction. Maintaining a degree of gas permeability is not shown as preventing the VFRB process from working, given the similar structure shown by ‘891 for use with a VFRB system. Similarly, this would also be the case for Verzwyvelt, where the citation also indicates that while gas permeability is maintained, better ionic conductivity is provided. Note also that Verzwyvelt also even indicates that conditions can be adjusted so as to reduce gas permeability (note column 3, lines 1-15), and thus if desired for the particular battery used, conditions can be provided so less porous and rely on hydrogen exchange, as well. As to forming a dense separator in the present application, degree of density is not claimed. Applicant’s attorney is making the argument that gas porosity is bad for the VRFB and density would be required, where it is argued that if a porous structure formed, allowing transfer of active material, problems of cross-over, short circuiting will occur, but a showing is not made as to this issue or as to what degree of density or lack of porosity would be required for VRFB. Note as discussed in MPEP 716.01(c)(II), “Arguments presented by the applicant cannot take the place of evidence in the record. In re Schulze, 346 F.2d 600, 602, 145 USPQ 716, 718 (CCPA 1965) and In re De Blauwe, 736 F.2d 699, 705, 222 USPQ 191, 196 (Fed. Cir. 1984). Examples of statements which are not evidence and which must be supported by an appropriate affidavit or declaration include statements regarding unexpected results, commercial success, solution of a long-felt need, inoperability of the prior art, invention before the date of the reference, and allegations that the author(s) of the prior art derived the disclosed subject matter from the inventor or at least one joint inventor. “ and also note MPEP 2145, “Arguments presented by applicant cannot take the place of evidence in the record. See In re De Blauwe, 736 F.2d 699, 705, 222 USPQ 191, 196 (Fed. Cir. 1984); In re Schulze, 346 F.2d 600, 602, 145 USPQ 716, 718 (CCPA 1965); In re Geisler, 116 F.3d 1465, 43 USPQ2d 1362 (Fed. Cir. 1997) ("An assertion of what seems to follow from common experience is just attorney argument and not the kind of factual evidence that is required to rebut a prima facie case of obviousness.").” As to the further arguments as to the use of ‘891, use of pre-doping and equilibrating is not prevented as claimed. As to the use of Gubler article, while it does not apply the PBI to a porous substrate, it still indicates m-PBI as a material for VRFB separators, where ‘891 also notes this.
Thirdly, as to the use of ‘465, and Staiti article, while they do not provide all the details of forming the separator as claimed, they are both cited as to how dissolving the PBI material can be provided. The combination of references is what provides all features claimed.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/KATHERINE A BAREFORD/Primary Examiner, Art Unit 1718
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