Prosecution Insights
Last updated: April 19, 2026
Application No. 17/918,571

ASYMMETRIC POROUS MEMBRANE

Final Rejection §102§103
Filed
Oct 13, 2022
Examiner
CLARY, KAYLA ELAINE
Art Unit
1721
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Celgard LLC
OA Round
2 (Final)
69%
Grant Probability
Favorable
3-4
OA Rounds
3y 3m
To Grant
98%
With Interview

Examiner Intelligence

Grants 69% — above average
69%
Career Allow Rate
57 granted / 83 resolved
+3.7% vs TC avg
Strong +30% interview lift
Without
With
+29.7%
Interview Lift
resolved cases with interview
Typical timeline
3y 3m
Avg Prosecution
37 currently pending
Career history
120
Total Applications
across all art units

Statute-Specific Performance

§101
0.4%
-39.6% vs TC avg
§103
45.9%
+5.9% vs TC avg
§102
20.8%
-19.2% vs TC avg
§112
21.7%
-18.3% vs TC avg
Black line = Tech Center average estimate • Based on career data from 83 resolved cases

Office Action

§102 §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 . Claim Rejections - 35 USC § 102 The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action: A person shall be entitled to a patent unless – (a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention. (a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention. Claim(s) 1, 5, 7, 12, 20, 57, and 61 is/are rejected under 35 U.S.C. 102(1)(a) as being anticipated by Stokes et al. (US-20170084898-A1). Regarding Claim 1, Stokes discloses: A dry-process porous membrane comprising (multilayer dry process microporous separator, see Abstract), two outer layers and optionally at least one inner layer (the example shown in Figs. 22A-22B has two outer layers and one inner layer), wherein the ratio of the thickness of one of the two outer layers to the other one of the two outer layers is from 1.1:1 to 4:1, from 1:1:1 to 3:1, or from 1.1:1 to 2:1 (The example shown in Fig. 22A-22B indicated the outer layers have a thickness of 2.19 and 1.72. The ratio of which is 2.19/1.72= 1.27 which is within the claimed range.). Stokes’ example shown in Fig. 22A-22B has a thickness of about 11.1 (1.72+2.19+7.19= 11.1, see [0065] and annotated Fig. 22A below) which is within the claimed range of: wherein the total thickness of the porous membrane is from 5 to 30 microns, from 5 to 20 microns, from 5 to 15 microns, or from 5 to 10 microns. Note, the measurement of the internal layer given in annotated Fig. 22A below is based on the SEM cross sectional image performed in PowerPoint as an approximation. Note, The “dry-process” limitation in Claim 1 is considered product-by-process claim. The cited prior art teaches all of the positively recited structure of the claimed apparatus or product. The determination of patentability is based upon the apparatus structure itself. The patentability of a product or apparatus does not depend on its method of production or formation. If the product in the product-by-process claim is the same as or obvious from a product of the prior art, the claim is unpatentable even though the prior product was made by a different process. See In re Thorpe, 777 F.2d 695, 698, 227 USPQ 964, 966 (Fed. Cir. 1985) (see MPEP § 2113). PNG media_image1.png 913 1228 media_image1.png Greyscale Regarding Claim 5, Stokes’ example show in Fig. 22a-22B is a 3 layer structure, thereby, teaching: comprising between 1 and 10 inner layers (1 inner layer). Regarding Claim 7, Stokes discloses “a multilayer polyolefin membrane for a rechargeable lithium battery which is manufactured using a lamination process, a coextruded process or a combination of the two processes,” see [0056], thereby, teaching: wherein the porous membrane is formed by a method that comprises: laminating at least one of the two outer layers with at least one inner layer; or co-extrusion of at least one of the two outer layers with at least one inner layer. Regarding Claim 12, Stokes’ example shown in Fig. 22A-22B has a thickness of about 11.1 (1.72+2.19+7.19= 11.1, see [0065] and annotated Fig. 22A below) which is within the claimed range of: wherein the total thickness of the porous membrane is from 5 to 20 microns, from 5 to 15 microns, or from 5 to 10 microns. Note, the measurement of the internal layer given in annotated Fig. 22A below is based on the SEM cross sectional image performed in PowerPoint as an approximation. Regarding Claim 20, Stokes discloses: wherein the porous membrane is formed by a method that comprises: laminating at least one of the two outer layers to the other of the two outer layers; or co-extrusion of the two outer layers (the multilayered polyolefin membrane can suitably be made via coextrusion, laminating, or a combination therefore , see [0056]). Regarding Claim 57, Stokes discloses: wherein the porous membrane is a multilayer porous membrane, the porous membrane is a multilayer porous membrane and two or more layers of the porous membrane are co-extruded (the multilayered polyolefin membrane can suitably be made via coextrusion, see [0056]), the porous membrane is a multilayer porous membrane comprising four or more layers (optional limitation), or the porous membrane is a multilayer porous membrane comprising four or more layers and two or more layers of the porous membrane are co-extruded (optional limitation). Regarding Claim 61, under broadest reasonable interpretation because Claim 1 and Claim 61 does not recite any structural distinctions between the inner the example shown in Figs. 22A-22B can be dissected in the way shown in annotated Fig.22A below. This interpretation meets the Claim 1 (7.40/3.70 = 2 making a ratio of 2:1) and the following: wherein the porous membrane does not contain an inner layer, and one of the outer layers may comprise PE and another of the outer layers may comprise PP (The interpretation shown in annotated Fig. has the two outer layers which both contain polypropylene and polyethylene. This limitation is interpreted as optional due to the recitation of “may” qualifiers.). PNG media_image2.png 717 1439 media_image2.png Greyscale Claim Rejections - 35 USC § 103 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. Claim(s) 9 is/are rejected under 35 U.S.C. 103 as being unpatentable over Stokes et al. (US-20170084898-A1) as applied to Claim 1 above. Regarding Claim 9, Stokes’ example shown in Fig. 22A and 22B has a layer composition of polyethylene/polypropylene/polyethylene, see [0065]. Therefore, that example does not teach: wherein the outer two layers comprise, consist, or consist essentially of polypropylene and the at least one inner layer comprises, consists of, or consists essentially of polyethylene However, Stokes teaches that polypropylene/polyethylene/polypropylene layering compositions is suitable for the microporous membrane of his invention, see [0056]. Therefore, absent a showing of persuasive secondary considerations, it would have been obvious to one of ordinary skill in the art at the time the instant invention was filed to have provided a microporous membrane that is polypropylene/polyethylene/polypropylene with the dimensions given in Figs. 22A-22B, because Stokes teaches that this is a suitable configuration for the devices of his invention. Response to Arguments Applicant's arguments filed 12/04/2025 have been fully considered and are addressed below. Specification The amendment to the Title is accepted and the objection is withdrawn. Claim Objections The amendments to Claim 61 overcome the previously objected informalities. The objection to Claim 61 is withdrawn. Rejections under 35 U.S.C. 102 & 103 Applicant argues on pages 14-16 that the SEM images shown in Figs. 22A and 22B are a direct image of the cross sections of the membrane not a mere diagram. The Examiner appreciates the detail analysis as to the inaccuracies of using the scale bar of the SEM image in PowerPoint to measure the inner layer on page 16 of the response. However, the given value in the rejection is an approximation. It is the Examiner’s position that the skilled artisan would readily acknowledge the total thickness of the porous membrane falls within the range of 5-30 microns based on the SEM images shown in Fig. 22A-22B. Additionally, the examples shown in Fig. 21B and Fig. 22A-22B are both produced using Comparative Example 5 as a starting material wherein the separator of Fig. 21B is produced through symmetrical calendaring and the separator of Fig. 22A-22B is produced by asymmetric calendaring, see also [0043]-[0044]. Stokes teaches the interlayer of the example shown in Fig. 21B after calendaring was 7.7 μm, see [0065]. Therefore, the approximation given above gives at least a reasonable value for the inner layer for the example shown in Fig. 22A-22B. Pertinent Prior Art The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Lie et al (US-20140272533-A1): Lie discloses a two layer porous with one layer made with polypropylene and the other with polyethylene. The example shown in Fig. 3 reproduced below has a ratio of thickness of (12.4/9.84= 1.26) 1:1.26. PNG media_image3.png 358 716 media_image3.png Greyscale 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 Kayla E Clary whose telephone number is (571)272-2854. The examiner can normally be reached Monday - Friday 8:00-5:00 (PT). 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. /K.E.C./ Kayla E. ClaryExaminer, Art Unit 1721 /ALLISON BOURKE/Supervisory Patent Examiner, Art Unit 1721
Read full office action

Prosecution Timeline

Oct 13, 2022
Application Filed
Sep 03, 2025
Non-Final Rejection — §102, §103
Dec 04, 2025
Response Filed
Mar 06, 2026
Final Rejection — §102, §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

3-4
Expected OA Rounds
69%
Grant Probability
98%
With Interview (+29.7%)
3y 3m
Median Time to Grant
Moderate
PTA Risk
Based on 83 resolved cases by this examiner. Grant probability derived from career allow rate.

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