DETAILED ACTION
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 .
Response to Amendments
This is a final office action in response to applicant's arguments and remarks filed on
12/17/2025.
Status of Rejections
All previous rejections are maintained.
Claims 1-9 are pending and under consideration for this Office Action.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claim(s) 1-3 and 5-8 is/are rejected under 35 U.S.C. 103 as being unpatentable over Prasnikar et al (US 5989396 A) in view of Calderara et al (WO 2016207209 A1) and Lotfield (US 3779889 A).
Claim 1: Prasnikar discloses a chlorination electrolyser (see e.g. abstract and Fig 1) comprising:
a housing (see e.g. #51 on Fig 1) provided with an inlet and an outlet suitable for the circulation of brine (see e.g. col 10, lines 55-62);
at least one pair of bipolar electrodes facing each other and positioned within said housing (see e.g. #10A on Fig 1);
characterized in that each bipolar electrode being an anode or a cathode (see e.g. col 8, lines 15-17) of said at least one pair comprises:
a valve metal substrate (see e.g. col 8, lines 32-33); and
an active coating comprising at least one layer of a catalytic composition comprising ruthenium and titanium disposed over said substrate (see e.g. col 8, lines 1-14).
Prasnikar does not explicitly teach a top coating comprising at least one layer of a composition comprising oxides of tantalum, niobium, tin, or combinations thereof disposed over said active coating. Calderara teaches that electrodes having platinum group metal coatings, such as ruthenium or iridium, can leach into the electrolyte (see e.g. page 2, lines 16-25). To protect these catalyst coatings, Calderara teaches applying a top coating applied to the active coating (see e.g. page 3, lines 16-19) comprising tin (see e.g. claim 1) to prevent the active coating from leaching (see e.g. col 3, lines 17-19). Therefore, it would have been obvious to a person having ordinary skill in the art at the time of filing to modify the electrode of Prasnikar to include a top layer comprising tin over said active coating as taught in Calderara because the top layer prevents the active coating from leaching into the electrolyte and improves electrode life.
Prasnikar does not explicitly teach that each bipolar electrode is coated with a coating coated on a coated side, wherein the coated side of each bipolar electrode are facing each other. Prasnikar teaches the bipolar electrode faces that face each other have different coatings (see e.g. col 7, lines 47-67 and col 8, lines 1-13). Additionally, Prasnikar teaches the bipolar electrodes are used for preparing a disinfectant solution containing hypochlorite (see e.g. abstract). Lotfield teaches an electrolytic cell for generating hypochlorites (see e.g. abstract) for water treatment (see e.g. col 1, lines 37-43) wherein the cell comprises bipolar electrodes facing each other (see e.g. #18 on Fig 5). Each bipolar electrode has an anode coating and a cathode coating that can be the same (see e.g. col 6, lines 14-23), wherein the coating can include titanium and ruthenium (see e.g. col 5, lines 28-29). Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the instant invention to modify the electrolyzer of Prasnikar so that each face of the bipolar electrode has the same coating as taught in Lotfield because Lotfield teaches that titanium ruthenium coatings are suitable for the cathodic and anodic reactions needed for generating hypochlorite in water treatment.
Claim 2: Prasnikar in view of Calderara and Lotfield discloses that said catalytic composition comprises 10%-45% ruthenium and 55%-90% titanium expressed in weight percentage with respect to the element (see e.g. col 8, lines 1-14 of Prasnikar), which overlaps with the claimed range. MPEP § 2144.05 I states ‘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); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990)’.
Claim 3: Prasnikar in view of Calderara and Lotfield discloses that said catalytic composition further comprises 5% iridium (see e.g. claim 12 of Prasnikar).
Claim 5: Prasnikar in view of Calderara and Lotfield teaches said top coating comprises tin oxide (see e.g. claim 1 of Calderara). Prasnikar in view of Calderara further teaches that top coatings can consist of only tin oxide (page 2, lines 21-25 of Calderara), with some drawbacks. However, it would have been obvious to a person having ordinary skill in the art at the time of filing that a top layer consisting of only tin oxide could be used for provide some protection for the electrode.
Claim 6: Prasnikar in view of Calderara and Lotfield teaches said top coating has a thickness of 1-5 microns (see e.g. page 3, lines 21-22 of Calderara).
Claim 7: Prasnikar in view of Calderara and Lotfield teaches said top coating has total loads ranging from 6-9 g/m2 (see e.g. page 11, lines 13-14 and page 12, lines 19-20 of Calderara).
Claim 8: Prasnikar in view of Calderara and Lotfield a discloses that said valve metal substrate is titanium (see e.g. col 8, lines 32-33 of Prasnikar).
Claim(s) 4 is/are rejected under 35 U.S.C. 103 as being unpatentable over Prasnikar in view of Calderara and Lotfield as applied to claim 1 above, and in further view of Brichese et al (US 20140008215 A1).
Claim 4: Prasnikar in view of Calderara and Lotfield does not explicitly teach said active coating has a load of ruthenium of 1-30 g/m2. Brichese teaches an electrode coating comprising ruthenium (see e.g. abstract) for use in chloride related electrolytic processes similar to those taught in Prasnikar, (see e.g. [0001] and [0002]) using a ruthenium loading of 4-40 g/m2 (see e.g. [0005]). Therefore, it would have been obvious to a person having ordinary skill in the art at the time of filing to modify Prasknikar by using the loading for ruthenium taught in Brichese because Brichese teaches this is a suitable loading for chloride related electrolytic processes. The loading overlaps with the claimed loading. MPEP § 2144.05 I states ‘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); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990)’.
Claim(s) 9 is/are rejected under 35 U.S.C. 103 as being unpatentable over Prasnikar in view of Calderara and Lotfield as applied to claim 1 above, and in further view of Antozzi (US 2013/0087450 A1) and Benedetto (US 20160251763 A1).
Claim 9: Prasnikar in view of Calderara and Lotfield teaches an electrochlorination system (see e.g. abstract and Fig 1) comprising:
the chlorination electrolyser according to claim 1 (see rejection of claim 1 above); an electrolyte comprising a brine solution circulating within said chlorination electrolyser (see e.g. #9 on Fig 7).
Prasnikar in view of Calderara and Lotfield does not explicitly teach that the brine solution comprises 1-30 g/L NaCI. Antozzi teaches that 4 g/L NaCl is a sufficient brine concentration for the generation of hypochlorite (see e.g. abstract and [0019] of Antozzi). Therefore, it would have been obvious to a person having ordinary skill in the art at the time of filing to modify the system of Prasnikar by using the 4 g/L NaCl in the brine solution as taught in Antozzi because Antozzi teaches this is a sufficient concentration for brine for generating hypochlorite.
Prasnikar in view of Calderara and Lotfield does not explicitly teach that that system is self-cleaning comprising an electronic system for periodically reversing the polarity of the at least one pair of bipolar electrodes and electrically connected thereto. Benedetto teaches a bipolar electrolytic cell (see e.g. abstract) wherein the polarity it periodically reversed to prevent scaling on the surfaces of the electrode (see e.g. [0002] of Benedetto). Therefore, it would have been obvious to a person having ordinary skill in the art at the time of filing to modify the system of Prasnikar so that it comprises an electronic system for periodically reversing the polarity of the at least one pair of bipolar electrodes and electrically connected thereto as taught in Benedetto to prevent scale formation on the surfaces of the electrodes.
Response to Arguments
Applicant's arguments filed 12/17/2025 have been fully considered but they are not persuasive.
On page(s) 6, the Applicant argues that Calderara does not render a “distinct top coating layer disposed over an active coating” obvious when combined with Prasnikar because “Calderara's disclosure is generic to electrode protection and does not contemplate the claimed multilayer architecture specifically adapted for bipolar operation in brine electrolysis”. This is not considered persuasive. The protective layer of Calderara is explicitly disclosed as preventing the leaching of platinum group metal coatings into the electrolyte (see e.g. page 2, lines 16-25). Ruthenium is used in Prasnikar. MPEP § 2144 IV states that ‘The reason or motivation to modify the reference may often suggest what the inventor has done, but for a different purpose or to solve a different problem. It is not necessary that the prior art suggest the combination to achieve the same advantage or result discovered by applicant. See, e.g., In re Kahn, 441 F.3d 977, 987, 78 USPQ2d 1329, 1336 (Fed. Cir. 2006)’. The protective coating of Calderara is applied to an active coating as required by the claim and the disclosure would be applicable to a bipolar electrode like that taught in Prasnikar because of the teachings regarding the platinum group metals even though Calderara does not explicitly disclose a bipolar electrode.
The Applicant further argues that “Calderara's disclosure emphasizes tin-containing layers as a general protective measure, not as a structurally and functionally distinct top coating deliberately positioned over a Ru/Ti active layer”. However, Calderara clearly states that the protective material is a separate layer “…comprising at least one protective layer consisting of a mixture of oxides with a composition by weight referred to the metals comprising 89-97% tin … In one embodiment, the coating may comprise a protective layer external to the catalytic layer, especially effective in preventing the release of noble metal from the catalytic layer during the start-up phase or the early hours of operation of the electrode” (see e.g. page 3, lines 5-19).
On page(s) 6-7, the Applicant argues that Lotfield does not render the limitation requiring “that each bipolar electrode is coated on a coated side, wherein the coated sides of each bipolar electrode are facing each other” obvious because “[a]lthough Lotfield discloses bipolar electrodes for hypochlorite generation, its disclosure that anode and cathode coatings can be the same is generic and does not teach or suggest the specific multilayer Ru/Ti active coating with an overlying oxide top coating on facing electrode surfaces as claimed…Thus, arguing that Lotfield discloses that the anode and cathode coatings can be the same is permissive, not prescriptive. Lotfield does not teach or recommend identical coatings as an improvement nor does it identify any problem solved by making the coatings the same”. This is not considered persuasive. The Applicant argues that Lotfield only generically discloses that the cathode and anode coatings of the bipolar electrode can be the same. However, Lotfield is more specific. Each bipolar electrode has an anode coating and a cathode coating that can be the same (see e.g. col 6, lines 14-23), wherein the coating can include titanium and ruthenium (see e.g. col 5, lines 28-29). Prasnikar discloses that the active coating comprising at least one layer of a catalytic composition comprising ruthenium and titanium disposed over said substrate (see e.g. col 8, lines 1-14). Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the instant invention that the active coating of Prasnikar can be used for both the cathode and anode side of bipolar electrodes used in a chlorination electrolyser based on the disclosure of Lotfield. The reasons to combine references does not have to be an improvement as the Applicant argues. For example, KSR rationale G states that “Some teaching, suggestion, or motivation in the prior art that would have led one of ordinary skill to modify the prior art reference or to combine prior art reference teachings to arrive at the claimed invention” is suitable rationale for obviousness.
On page(s) 7, the Applicant argues that “Even if assuming arguendo, one skilled in the art would look at the disclosure of Lotfield, it would still be impossible to arrive at a top coating comprising oxides of tantalum, niobium, or tin, disposed over a Ru/Ti active coating for the purpose of stabilizing a bipolar electrode under chlorination conditions”. This is not considered persuasive. MPEP § 2144 IV states that ‘The reason or motivation to modify the reference may often suggest what the inventor has done, but for a different purpose or to solve a different problem. It is not necessary that the prior art suggest the combination to achieve the same advantage or result discovered by applicant. See, e.g., In re Kahn, 441 F.3d 977, 987, 78 USPQ2d 1329, 1336 (Fed. Cir. 2006)’. The combination of the references all complied with the standards of obviousness set by KSR and they are not required to use the reasoning of the instant applicants to arrive at the invention.
On page(s) 7, the Applicant argues that “Adding Calderar's top layer into a bipolar system is not trivial because a protective oxide layer that suppresses leaching may also reduce catalytic activity, increase overpotential, interfere with bipolar current distribution.” This is not considered persuasive. The Applicant is speculating about the top layer. MPEP § 716.01(c) II states that ‘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)’.
On page(s) 7, the Applicant argues that “In fact, Calderara teaches "protection", not bipolar compatibility when teaching to apply a protective top coating to reduce leaching. The Examiner's reasoning implicitly assumes that if a top coating reduces leaching in a generic electrode, it will also work in a bipolar chlorination electrolyzer. However, that assumption is unsupported by the cited art.” This is not cosndiered persuasive. The Applicant repeatedly states that Calderara teaches a “generic electrode”. However, Calderara explicitly teaches that the protective top coating is for active layers comprising platinum group metals (see e.g. page 3, lines 5-19).
On page(s) 8, the Applicant argues that none of the prior art supports using the protective layer for both sides of the bipolar electrode because “improving durability in the abstract is insufficient when the modification affects the electrochemical interface in a bipolar system. Calderara does not teach that its coating functions equivalently under anodic and cathodic conditions, as required in bipolar operation”. This is not considered persuasive. Prasnikar discloses a bipolar electrode comprising a valve metal substrate (see e.g. col 8, lines 32-33); and an active coating comprising at least one layer of a catalytic composition comprising ruthenium and titanium disposed over said substrate (see e.g. col 8, lines 1-14). Lotfield teaches a bipolar electrode comprising an active coating that can include titanium and ruthenium (see e.g. col 5, lines 28-29) wherein the bipolar electrode has an anode coating and a cathode coating that can be the same (see e.g. col 6, lines 14-23). Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the instant invention that the active coating comprising ruthenium and titanium can be applied to both the anode and cathode sides of the bipolar electrode. Calderara teaches that electrodes having platinum group metal coatings, such as ruthenium or iridium, can leach into the electrolyte (see e.g. page 2, lines 16-25). To protect these catalyst coatings, Calderara teaches applying a top coating applied to the active coating (see e.g. page 3, lines 16-19) comprising tin (see e.g. claim 1) to prevent the active coating from leaching (see e.g. col 3, lines 17-19). As both sides of the bipolar electrode for Prasnikar in view of Lotfield have platinum group metals, there would be motivation for one having ordinary skill in the art to protect both coatings. The teachings of disclosure would support adding the protective coating to active coatings comprising platinum group metals. According to Calderara, protective layer porosity and conductivity allows operation without detrimental effects on the electrode potential (see e.g. col 3, lines 22-26).
Conclusion
THIS ACTION IS MADE FINAL. 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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ALEXANDER W KEELING whose telephone number is (571)272-9961. The examiner can normally be reached 7:30 AM - 4:00 PM. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Luan Van can be reached at 571-272-8521. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/ALEXANDER W KEELING/Primary Examiner, Art Unit 1795