Prosecution Insights
Last updated: April 19, 2026
Application No. 17/788,764

SEPARATOR FOR ELECTROCHEMICAL ELEMENTS

Non-Final OA §103
Filed
Jun 24, 2022
Examiner
GRANNUM, VERITA EUDORA EBUN
Art Unit
1721
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Kuraray Co. Ltd.
OA Round
3 (Non-Final)
75%
Grant Probability
Favorable
3-4
OA Rounds
3y 7m
To Grant
99%
With Interview

Examiner Intelligence

Grants 75% — above average
75%
Career Allow Rate
9 granted / 12 resolved
+10.0% vs TC avg
Strong +56% interview lift
Without
With
+55.6%
Interview Lift
resolved cases with interview
Typical timeline
3y 7m
Avg Prosecution
59 currently pending
Career history
71
Total Applications
across all art units

Statute-Specific Performance

§103
59.3%
+19.3% vs TC avg
§102
24.9%
-15.1% vs TC avg
§112
15.8%
-24.2% vs TC avg
Black line = Tech Center average estimate • Based on career data from 12 resolved cases

Office Action

§103
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 . 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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 submission filed on 10/28/2025 has been entered. Response to Arguments Applicant’s arguments with respect to claim 1 has been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument. 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. 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. 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. Claims 1-3 and 5-12 are rejected under 35 U.S.C. 103 as being unpatentable over Ochi (US 20220059291 A1) and further in view of Igawa (US 20180287119 A1). Regarding claim 1, Ochi teaches a separator (abstract) for electrochemical elements (abstract, [a solid electrolytic capacitor]), the separator comprising synthetic fibers (abstract, [the separator contains synthetic fiber]) and beaten cellulose fibers (abstract, [(the separator contains) fibrillated natural cellulose fiber]), wherein the beaten cellulose fibers have a Canadian standard freeness measured in accordance with JIS P 8121 of 50 ml or more and 500 ml or less (para. 0077, [a CSF value of the fiber constituting the separator is set in a range of 0 to 500 ml]). Ochi does not teach that the beaten cellulose fibers have a number average fiber diameter of 13 µm or more. Igawa, in the same field of endeavor, beaten cellulose fibers used in separators, teaches beaten cellulose fibers having a number average fiber diameter of 13 µm or more (Igawa, para. 0119, [an average fiber width of 18 µm])(Examiner notes that in para. 0117, Igawa teaches that Lyocell fibers are regenerated cellulose fibers and teaches that in para. 0119 the Lyocell fibers were beaten). It would have been obvious to a person of ordinary skill in the art, before the effective filing date of the claimed invention, to have processed Ochi’s beaten cellulose fibers to have a number average fiber diameter of 18 µm, as taught by Igawa, in order to make a separator in which the denseness can be increased without deterioration of the strength of the separator, thereby providing a good separator having high shielding performance, as taught by Igawa (Igawa, para. 0045). Modified Ochi does not teach: in a fiber diameter distribution histogram of the beaten cellulose fibers, (1) the fibers have a maximum frequency peak in a range of 14 µm to 50 µm (2) a ratio of the fibers having a fiber diameter of 20 µm or less is 55% or more Modified Ochi teaches fibers with an average diameter of 18 µm. It would have been obvious to a person of ordinary skill in the art, before the effective filing date of the claimed invention, to have processed the cellulose fibers to obtain fibers within the frequency peak of 18 µm, and to obtain a ratio of 55% or more of fibers having a diameter of 18 µm, in order to make a separator in which the denseness can be increased without deterioration of the strength of the separator, thereby providing a good separator having high shielding performance, as taught by Igawa (Igawa, para. 0045). Regarding claim 2, modified Ochi teaches the separator for electrochemical elements according to claim 1, and Ochi further teaches a binder (para. 0078, [a resin such as polyvinyl alcohol … can be used as the binder material]). Regarding claim 3, modified Ochi teaches the separator for electrochemical elements according to claim 1 and as discussed above, teaches the cellulose fiber diameter to be 1 micron, which reads on a ratio of the fibers having a fiber diameter of more than 30 µm is 10% or less (none) Regarding claim 5, modified Ochi teaches the separator for electrochemical elements according to claim 1, and Ochi further teaches the beaten cellulose fibers are beaten natural cellulose fibers (para. 0051, [fibrillated natural cellulose fiber]). Regarding claim 6, modified Ochi teaches the separator for electrochemical elements according to claim 2, and Ochi further teaches that the binder is a polyvinyl alcohol-based binder (para. 0078, [a sealing resin such as polyvinyl alcohol … can be used as the binder material]). Regarding claim 7, modified Ochi teaches the separator for electrochemical elements according to claim 1, and Ochi further teaches a content of the synthetic fibers is 1% by mass or more and 55% by mass or less based on a total mass of the separator (abstract, [the synthetic fiber contains 20-80 mass %]). Regarding claim 8, modified Ochi teaches the separator for electrochemical elements according to claim 1, and Ochi further teaches a content of the beaten cellulose fibers is 30% by mass or more and 95% by mass or less based on a total mass of the separator (abstract, [the content of fibrillated natural cellulose fiber is 20-80 mass %]). Regarding claim 9, modified Ochi teaches the separator for electrochemical elements according to claim 2, and Ochi further teaches a content of the binder is 0.5% by mass or more and 20% by mass or less based on a total mass of the separator (para. 0078, [the content of the binder material is not particularly limited … however when the content is up to about 30 mass % (reading on all ranges), the impregnation property is hardly affected]. Regarding claim 10, modified Ochi teaches the separator for electrochemical elements according to claim 1, and Ochi further teaches that the separator has a thickness of 10 µm or more and less than 70 µm (para. 0079, [the thickness is about 20 to 70 µm]). Regarding claim 11, modified Ochi teaches an electrochemical element comprising the separator for electrochemical elements according to claim 1 (abstract, [solid electrolytic capacitor using the separator]). Regarding claim 12, modified Ochi teaches the separator for electrochemical elements according to claim 2, and Ochi further teaches that a content of the binder is 0.5% by mass or more and 8% by mass or less based on a total mass of the separator (para. 0078, [the content of the binder material is not particularly limited … however when the content is up to about 30 mass %, the impregnation property is hardly affected]. Ochi teaches about the effects of having a content mass of 30 and below, which then teaches that it is possible to have a binder content mass % of 0.5% to 20%.) Claim 4 is rejected under 35 U.S.C. 103 as being unpatentable over Ochi (US 20220059291 A1) in view of Igawa (US 20180287119 A1), and further in view of Tanaka (US 20160293338 A1). Regarding claim 4, modified Ochi teaches the separator for electrochemical elements according to claim 1, and Ochi further teaches that the synthetic fibers are polyamide-based fibers. Ochi does not teach that the synthetic fibers are polyvinyl alcohol-based fibers. Tanaka, in the same field of endeavor, fibrous separators, teaches that the fibrous component of the separator may be at least one of a polyvinyl alcohol fiber, polyamide fiber and/or regenerated cellulose fiber (para. 0062). Tanaka lists various examples of materials that can be used for the fibrous component of the separator. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the separator of Ochi by replacing the polyamide fiber of Ochi with the polyvinyl alcohol fiber as taught by Tanaka. The simple substitution of a known element (polyamide) for another (polyvinyl alcohol) would achieve the predictable result of providing a fibrous component that can be used to make a separator with excellent impedance characteristics and short-circuit resistance characteristics, as disclosed by Tanaka (abstract). See KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 415-421, 82 USPQ2d 1385, 1395-97 (2007). Other Pertinent Art Mizobuchi (US 6074523 A) “Fibers of Manila hemp pulp have a Substantially circular shape and a diameter of about 20 lum. In the case of the Manila hemp pulp, the extent of beating can be grasped as a variation in the rate of fibers having a diameter of 20 um to fibrils having a diameter of 0.4 um.” (Mizobuchi, column 6, first paragraph) Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to VERITA E GRANNUM whose telephone number is (571)270-1150. The examiner can normally be reached 10-5 EST / 7-2 PST. 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, Allison Bourke can be reached at (303) 297-4684. 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. /V.G./Examiner, Art Unit 1721 /ALLISON BOURKE/Supervisory Patent Examiner, Art Unit 1721
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Prosecution Timeline

Jun 24, 2022
Application Filed
Apr 11, 2025
Non-Final Rejection — §103
Jul 18, 2025
Response Filed
Jul 24, 2025
Final Rejection — §103
Oct 28, 2025
Request for Continued Examination
Oct 29, 2025
Response after Non-Final Action
Mar 06, 2026
Non-Final Rejection — §103 (current)

Precedent Cases

Applications granted by this same examiner with similar technology

Patent 12597637
SOLID ELECTROLYTE AND ALL-SOLID-STATE BATTERY
2y 5m to grant Granted Apr 07, 2026
Patent 12531237
LITHIUM ION SECONDARY BATTERY
2y 5m to grant Granted Jan 20, 2026
Patent 12418031
Electrode and Electrode Assembly
2y 5m to grant Granted Sep 16, 2025
Study what changed to get past this examiner. Based on 3 most recent grants.

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Prosecution Projections

3-4
Expected OA Rounds
75%
Grant Probability
99%
With Interview (+55.6%)
3y 7m
Median Time to Grant
High
PTA Risk
Based on 12 resolved cases by this examiner. Grant probability derived from career allow rate.

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