DETAILED ACTION
Notice of Pre-AIA or AIA Status
1. The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Response to Amendments
2. The applicant’s response dated 05 May 2026 has been entered into the record. The applicant’s claim amendments do not introduce any new subject matter. The applicant’s response is considered fully responsive. The applicant has cancelled Claims 17 and 18. Claims 16, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, and 30 are currently pending and under examination.
Claim Rejections - 35 USC § 103
3. 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.
4. 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.
5. Claims 16, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, and 29 are rejected under 35 U.S.C. 103 as being unpatentable over Doyan et al. and Hansen et al.
Doyan et al. (US Pub. No. 20070286949A1 – previously presented) is drawn toward a web-reinforced separator and continuous method for producing the same (title). Hansen et al. (WO2018001448A1) is directed toward a separator for electrochemical conversion processes (title).
Regarding Claim 16, Doyan et al. discloses an ion permeable web reinforced separator (abstract) which is useful for alkaline water hydrolysis (¶82) and analogous to the separator of Claim 1. Doyan et al. further discloses a porous support selected from polyethersulfone (“PES”) Spunlaid non-woven web, polyamide (“PA”) woven web, or polyether ether ketone (“PEEK”) woven web (¶34 and Table 1). The porous support of Doyan et al. is coated with a hydrophilic layer using a hybrid paste detailed in ¶38-47. Example 1 of Doyan et al. indicates the aforementioned paste comprises 46.99 wt.% DMF (solvent), 13.25 wt.% polysulfone (“PSf”, polymer of the instant application), and 39.75 wt.% titanium dioxide (hydrophilic inorganic particle of the instant application) (¶56-59). The particle size of TiO2 in Example 1 was 0.320 microns according to ¶59. When the ratio of the inorganic particle to polymer resin is normalized to 100%, the ratio is 75/25. Doyan et al. meets the particle size limitation of the inorganic particle and the ratio of the inorganic particle to the polymer resin. However, Doyan et al. does not disclose the inorganic particle is barium sulfate.
Hansen et al. is directed toward a separator that is mechanically strong and durable and can be used in various electrochemical conversion processes such as alkaline water electrolysis (pg. 6 lines 14-25). Therefore, Hansen et al. is analogous art to Doyan et al. Hansen et al. further indicates that the separator is formed by application of a paste comprising a polymer resin and a mixture of metal oxide and inorganic fibers in a solvent to a porous material. On pg. 4 lines 28-34, Hansen et al. indicates that the inorganic fiber provides hydrophilicity and ionic conductivity with selection from potassium titanate, zirconia, barium sulfate, and Wollansanite. On pg. 9 lines 1-7, Hansen et al. indicates that the metal oxides are selected from titanium dioxide and zirconia for the purpose of improving the hydrophilicity and ionic conductivity of the membrane (pg. 5 lines 34-38 to pg. 6 lines 1-2). Hansen et al. details the general procedure of preparing the casting solution on pg. 8 lines 9-25 indicating the polymer resin (e.g.: PVDF, polyacrylonitrile, polyethylene oxide, or PMMA) is dissolved in a solvent (e.g.: NMP or DMF) to the addition of the hydrophilic additives (i.e.: the metal oxide and the inorganic fiber) and cast onto a porous substrate.
Since the hydrophilic additives in Doyan et al. and Hansen et al. are similar (e.g.: barium sulfate, titanium dioxide, and zirconia) and serve the same purpose (i.e., increase ionic conductivity and provide mechanical strength to the separator), they are recognized as equivalent at least by the prior art cited. According to MPEP 2144.06, it is prima facie obvious to substitute one known element for another known provided it is for the same purpose. Therefore, it would be obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to substitute the titania inorganic particle in the separator of Doyan et al. with barium sulfate as taught in Hansen et al. with the reasonable expectation of forming a separator with equivalent performance. Additionally, barium sulfate is known to be very inert in alkaline solutions (i.e.: the electrolyte of an alkaline water electrolysis cell) since barium hydroxide is soluble meaning there will be little degradation of the inorganic filler (i.e.: no salt metathesis, or sulfate/hydroxide exchange) when the separator is exposed to the caustic electrolyte.
Regarding Clam 19, Doyan et al. in view of Hansen et al. discloses the separator of Claim 16 wherein the porous support comprises two porous hydrophilic polymer layers contiguous with both sides of the support (abstract, ¶9-14, and FIG. 1 in Doyan et al.).
Regarding Claim 20, Doyan et al. in view of Hansen et al. discloses the separator of Clam 16, wherein the polymer resin is polysulfone as per Ex. 1 of Doyan et al. (¶58). In ¶39 and Claim 14, Doyan et al. further indicates the polymer resin (i.e.: organic binder) can be polyethersulfone (“PES”) or polyphenylsulfone (“PPS”).
Regarding Claim 21, Doyan et al. in view of Hansen et al. discloses the separator of Claim 16, but does not specify the exact the maximal pore diameter. Doyan et al. further indicates that the surface pore formation step comprises exposing the coated web to a water vapor phase (¶13) and the vapor exposure conditions dictate the pore size characteristics (i.e.: the maximal pore diameter) allowing for asymmetric pores on each side of the separator (¶23). Therefore, the vapor exposure condition is a result-effective variable, i.e., a variable which achieves a recognized result, and the determination of the optimum or workable ranges of said variable might be characterized as routine experimentation (See MPEP 2144.0.II.B.). Accordingly, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to have discovered the optimum or workable ranges of the maximal pore size diameter, including values within the claimed range, through routine experimentation by changing the vapor exposure conditions. One would have been motivated to do so in order to have formed a coated membrane for alkaline hydrolysis that provides high ionic conductivity and mechanical strength by careful tuning of the pore size.
Regarding Claim 22, Doyan et al. in view of Hansen et al. the method of preparing a separator for alkaline water electrolysis according to Claim 16, the method comprising the steps of: applying a dope solution comprising a polymer resin (e.g.: PSf in Doyan et al.), barium sulfate particles having a particle size D50 of ~0.32 microns (Ex. 1 of Doyan et al.), a solvent (DMF in Ex. 1 of Doyan et al.) on a porous support (e.g.: PES), and subjecting the applied dope solution to phase inversion (Doyan et al. ¶9-17 and ¶41-67)
Regarding Claim 23, Doyan et al. in view of Hansen et al. discloses the method of Claim 22, wherein the porous support comprises two porous hydrophilic polymer layers contiguous on both sides of the porous support as detailed in FIG. 1 and ¶41-54 of Doyan et al.
Regarding Claim 24, Doyan et al. in view of Hansen et al. discloses the method of Claim 22, wherein the dope solution (i.e.: the paste in Doyan et al./Hansen et al.) is applied on either side of the porous support as illustrated in FIG. 1
Regarding Claim 25, Doyan et al. in view of Hansen et al. discloses the method of Claim 22, wherein the solvent of the dope solution is selected DMF (Ex. 1 in Doyan et al.) or N-methyl-2-pyrrolidone (NMP) (Doyan et al. in ¶40) or N,N-dimethylacetamide (DMAC) (Doyan et al. in ¶40).
Regarding Claim 26, Doyan et al. in view of Hansen et al. discloses the method of Claim 22, wherein the dope solution further comprises polyvinylpyrrolidone as supported by Doyan et al. by the use of a hydrophilic resin (e.g.: PVP) in the paste according to Claim 13 and ¶14.
Regarding Claim 27, Doyan et al. in view of Hansen et al. discloses the method of Claim 22, wherein the phase inversion step includes a Vapor Induced Phase Separation (VIPS) step and a Liquid Induced Phase Inversion (LIPS) step as indicated in Doyan et al. (¶12-14, ¶48-54, and FIG. 1).
Regarding Claim 28, Doyan et al. in view of Hansen et al. discloses the method of Claim 22, wherein the LIPS step is carried out in a coagulation bath comprising water (¶55-67 of Doyan et al.)
Regarding Claim 29, Doyan et al. in view of Hansen et al. discloses the method of Claim 22, wherein the porous support is transported in a vertical position in the application step and the phase inversion step (Doyan et al. in FIG. 1 and ¶48-54).
6. Claim 30 is rejected under 35 U.S.C. 103 as being unpatentable over Doyan et al. in view of Hansen et al. as applied to Claim 16 above, and further in view of Stojadinovic et al.
Doyan et al. (US Pub. No. 20070286949A1 – previously presented) is drawn toward a web-reinforced separator and continuous method for producing the same (title). Hansen et al. (WO2018001448A1) is directed toward a separator for electrochemical conversion processes (title). Stojadinovic et al. (US Pub. No. 2018/0080131 A1 – previously presented) is directed toward a woven or non-woven web comprising polymer fibers and inorganic salts for use in alkaline water electrolysis (abstract).
Regarding Claim 30, Doyan et al. in view of Hansen et al. disclose the alkaline water electrolysis separator of Claim 16, but do not explicitly demonstrate its use in a device. However, one of ordinary skill in the art would examine other references that explicitly disclose the use of a BaSO4/polymer separator used in an alkaline water electrolysis device.
Stojadinovic et al. discloses a separator for alkaline water hydrolysis (i.e.: woven or non-woven web for use in alkaline water hydrolysis in abstract and Claims 40-42). The separator comprises a hydrophilic polymer coating (¶61; e.g.: polysulfone, polyethersulfone, and polyarylketones; all have polar groups such as R2C=O, RSO2R, and R-O-R) and hydrophilic inorganic particles including: barium sulfate. Stojadinovic et al. further discloses an alkaline water electrolysis device comprising a separator containing the BaSO4/polymer hybrid coating located between an anode and a cathode as described in ¶58 in which the cell voltage vs. current density (data shown in FIG. 22) was evaluated using a 30% KOH in water electrolyte (i.e.: in a water electrolysis device.
Given the similar structure between the separator of Stojadinovic et al. and Doyan et al./Hansen et al., it would be obvious to one ordinary skill in the art prior to the effective filing date of the claimed invention to use the membrane of Doyan et al. in view of Hansen et al. in the alkaline water electrolysis device of Stojadinovic et al. with the reasonable expectation for forming a water electrolysis device having high ionic conductivity and a structurally robust membrane.
Response to Arguments
7. Applicant’s arguments, filed 05 May 2026, with respect to the rejection(s) of Claims 16, and 19-30 under 102/103 have been fully considered and are persuasive. The examiner generally agrees that the combination of Stojadinovic et al. and/or Vogt et al. does not teach the ratio of BaSO4/polymer of 75/25 or greater. This value was included in the amendment to Claim 16. Therefore, the previous rejection has been withdrawn. However, upon further consideration, a new ground of rejection is made in view of Doyan et al. and Hansen et al. for Claims 16, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, and 29 and a new ground of rejection is made in view of Doyan et al., Hansen et al., and Stojadinovic et al. for Claim 30. The updated reasons for the rejection are discussed in detail above.
Conclusion
8. Any inquiry concerning this communication or earlier communications from the examiner should be directed to KEVIN SYLVESTER whose telephone number is 703-756-5536. The examiner can normally be reached Mon - Fri 8:15 AM to 4:30 PM EST.
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/KEVIN SYLVESTER/Examiner, Art Unit 1794
/JAMES LIN/Supervisory Patent Examiner, Art Unit 1794
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