Prosecution Insights
Last updated: April 19, 2026
Application No. 18/019,935

ELECTRET WEBS WITH BENZOATE SALT CHARGE-ENHANCING ADDITIVES

Non-Final OA §102§103§112
Filed
Feb 06, 2023
Examiner
MCKENZIE, THOMAS B
Art Unit
1776
Tech Center
1700 — Chemical & Materials Engineering
Assignee
3M Company
OA Round
3 (Non-Final)
57%
Grant Probability
Moderate
3-4
OA Rounds
3y 3m
To Grant
80%
With Interview

Examiner Intelligence

Grants 57% of resolved cases
57%
Career Allow Rate
551 granted / 961 resolved
-7.7% vs TC avg
Strong +23% interview lift
Without
With
+22.9%
Interview Lift
resolved cases with interview
Typical timeline
3y 3m
Avg Prosecution
91 currently pending
Career history
1052
Total Applications
across all art units

Statute-Specific Performance

§101
1.0%
-39.0% vs TC avg
§103
46.5%
+6.5% vs TC avg
§102
17.6%
-22.4% vs TC avg
§112
27.5%
-12.5% vs TC avg
Black line = Tech Center average estimate • Based on career data from 961 resolved cases

Office Action

§102 §103 §112
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 Objections Claim 17 is objected to because it has the status identifier of “Previous presented” when it was cancelled in the claim set dated August 28, 2025. Appropriate correction is required. Claim Rejections - 35 USC § 112(b) The following is a quotation of 35 U.S.C. 112(b): (b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention. The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph: The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention. Claims 1–4, 8, 10–11, 15 and 18–20 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention. Claims 1 and 10 recites: 1. An electret web consisting of: a polypropylene resin; and a charge-enhancing additive comprising a benzoate salt with the general structure of Formula 1: PNG media_image1.png 253 320 media_image1.png Greyscale wherein the groups R1, R2, R3, R4 and R5 independently are a hydrogen atom, an alkyl, an aryl, or a substituted alkyl; and M is a metal ion with a valency of 2, wherein the electret web contains an electrostatic charge. 10. An electret filter medium consisting of: a web consisting of: a polypropylene resin; and a charge-enhancing additive comprising a benzoate salt with the general structure of Formula 1: PNG media_image1.png 253 320 media_image1.png Greyscale wherein the groups R1, R2, R3, R4 and R5 independently are a hydrogen atom, an alkyl, an aryl, or a substituted alkyl; and M is a metal ion with a valency of 2, wherein the electret web contains an electrostatic charge. Claims 1 and 10 are indefinite because it is unclear whether they are closed or open-ended. This is because the preamble indicates that each claim is closed by using the transitional phrase “consisting of.” But then the claim indicates that certain portions can be open-ended by using the transitional phrases “comprising” and “contains.” For instance, it is unclear whether the “charge-enhancing additive” can have elements in addition to the benzoate salt because the preamble says that each claim is closed (“consisting of”), but the charge-enhancing additive is open by saying it is an additive “comprising a benzoate salt.” Claims 2–4, 8, 11, 15 and 18–20 are indefinite because they depend from claims 1 or 10. Also, claims 2–4, 11, 18 and 20 are indefinite for reasons similar to claims 1 and 10 because each of claims 2–4, 11, 18 and 20 uses the open-ended transitional phrase “comprises” (or an equivalent). 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. Claims 1, 2, 4, 8, 10, 11, 15, 19 and 20 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Koori et al., US 2015/0368836 A1. Regarding claim 1, Koori teaches a fibrous non-woven fabric that can be used as an electret filter. See Koori [0001], [0063]. The fibrous non-woven fabric used as an electret filter reads on the “electret web.” The fibrous nonwoven fabric consists of a resin composition C of general-purpose polypropylene (as high-crystalline polyolefin A) and low-crystalline polypropylene (as low-crystalline polyolefin B) (see Koori [0012]–[0013], [0021]) and a release agent of metal salt of an organic carboxylic acid, where the metal is Mg and the organic carboxylic acid is benzoic acid (id. at [0038], [0041]–[0042]). The resin composition C reads on the “polypropylene resin” because it is a resin of polypropylene. The salt of Mg and benzoic acid reads on the claimed “charge-enhancing additive comprising a benzoate salt with the general structure of Formula 1” because a magnesium salt of benzoic acid is magnesium benzoate, which has the structure seen below, with magnesium having a valence of 2. Note that the limitation requiring the additive to function as a “charge-enhancing” additive fails to further limit the scope of the claim because it describes the intended use rather than the structure of the additive. See MPEP 2112(I) (something which is old does not become patentable upon the discovery of a new property). The fibrous non-woven fabric used as an electret filter contains an electrostatic charge, as claimed, because it is an electret material that has been subjected to electret processing. See Koori [0063]. Note that the Applicant acknowledges that an electret web has an electrostatic charge implicitly by the name “electret.” See Applicant Rem. filed August 28, 2025, 12. Note also that an “electret” is known in the art as a material that exhibits a quasi-permanent electrical charge. See e.g., Schultz et al., US 2019/0003112 A1, [0002]. PNG media_image2.png 383 592 media_image2.png Greyscale Regarding claim 2, Koori teaches that the electret filter comprises a non-woven fibrous web. See Koori [0001]. Regarding claim 4, Koori teaches that the internal release agent is magnesium benzoate, as explained in the rejection above. Magnesium benzoate has the general structure of claimed Formula 1, as seen in the chemical structure of magnesium benzoate provided in the rejection of claim 1 above. Regarding claim 8, Koori teaches that the internal release agent is magnesium benzoate, as explained in the rejection above. Magnesium benzoate has the general structure of claimed Formula 1C, as seen in the chemical structure of magnesium benzoate provided in the rejection of claim 1 above. Regarding claim 10, Koori teaches a fibrous non-woven fabric that can be used as an electret filter. See Koori [0001], [0063]. The fibrous non-woven fabric used as an electret filter reads on the “electret filter medium.” The fibrous nonwoven fabric consists of a “web,” as claimed, because the fibrous nonwoven fabric itself reads on the “web.” See Koori [0001], [0063]. The fibrous nonwoven fabric consists of a resin composition C of general-purpose polypropylene (as high-crystalline polyolefin A) and low-crystalline polypropylene (as low-crystalline polyolefin B) (see Koori [0012]–[0013], [0021]) and a release agent of metal salt of an organic carboxylic acid, where the metal is Mg and the organic carboxylic acid is benzoic acid (id. at [0038], [0041]–[0042]). The resin composition C reads on the “polypropylene resin” because it is a resin of polypropylene. The salt of Mg and benzoic acid reads on the claimed “charge-enhancing additive comprising a benzoate salt with the general structure of Formula 1” because a magnesium salt of benzoic acid is magnesium benzoate, which has the structure seen below, with magnesium having a valence of 2. Note that the limitation requiring the additive to function as a “charge-enhancing” additive fails to further limit the scope of the claim because it describes the intended use rather than the structure of the additive. See MPEP 2112(I) (something which is old does not become patentable upon the discovery of a new property). The fibrous non-woven fabric used as an electret filter contains an electrostatic charge, as claimed, because it is an electret material that has been subjected to electret processing. See Koori [0063]. Note that the Applicant acknowledges that an electret web has an electrostatic charge implicitly by the name “electret.” See Applicant Rem. filed August 28, 2025, 12. Note also that an “electret” is known in the art as a material that exhibits a quasi-permanent electrical charge. See e.g., Schultz et al., US 2019/0003112 A1, [0002]. PNG media_image2.png 383 592 media_image2.png Greyscale Regarding claim 11, Koori teaches that the internal release agent is magnesium benzoate, as explained in the rejection above. Magnesium benzoate has the general structure of claimed Formula 1, as seen in the chemical structure of magnesium benzoate provided in the rejection of claim 1 above. Regarding claim 15, Koori teaches that the internal release agent is magnesium benzoate, as explained in the rejection above. Magnesium benzoate has the general structure of claimed Formula 1C, as seen in the chemical structure of magnesium benzoate provided in the rejection of claim 1 above. Regarding claim 19, Koori teaches that the fibrous nonwoven fabric contains an electrostatic charge because it is an electret material that has been subjected to electret processing, as noted above. See Koori [0063]. The limitation describing that the electrostatic charge is imparted through corona treatment, hydrocharging or a combination therefore fails to further limit the scope of the claim because it describes the process of manufacturing the web instead of its structure. See MPEP 2113(I) (the patentability of a product does not depend on its method of production unless the process steps impart structure). Regarding claim 20, Koori teaches that the fibrous nonwoven fabric further comprises at least one additional additive selected from pigments, light stabilizers, nucleating agents, fluorine containing compounds and combinations thereof. See Koori [0050], [0061]. 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 3 is rejected under 35 U.S.C. 103 as being unpatentable over Koori et al., US 2015/0368836 A1 in view of Midkiff et al., US 2010/0326902 A1. Regarding claim 3, Koori teaches the limitations of claim 1, as explained above. Koori differs from claim 3 because it is silent as to the electret filter (the “web”) comprising a film. But Midkiff teaches a multilayer electret filtration media comprising a first layer made of a film. See Midkiff [0025]. The first layer is beneficial because it provides structural support to the filtration media. Id. It would have been obvious for the electret filter of Koori to comprise the first layer of Midkiff to provide structural support to the electret filter. With this modification, the fibrous non-woven fabric used as an electret filter of Koori “comprises a film,” as claimed, because the electret filter would include the first layer of Midkiff, in addition to the fibrous nonwoven fabric of Koori. Claim 18 is rejected under 35 U.S.C. 103 as being unpatentable over Koori et al., US 2015/0368836 A1. Regarding claim 18, Koori teaches that the internal release agent comprises between 10 to 10,000 ppm by mass of the resin composition used to manufacture the fibers of the nonwoven web. See Koori [0049]. The nonwoven fiber web is comprised mostly of the fibers. The range of 10 to 10,000 ppm by mass converts to 0.001 to 1% by mass. The prior art range of 0.001 to 1% by mass of the resin composition used to make the fibers of the nonwoven web either overlaps with or is close enough to the claimed range of 0.02 to 5.0 % by weight of the web to establish a prima facie case of obviousness. See MPEP 2144.05, subsection I. Response to Arguments The Applicant argues that claims 1 and 10 have been amended to limit the thermoplastic resin to a single resin by changing the transitional phrase from “comprising” to “consisting of.” See Applicant Rem. dated November 03, 2025 (“Applicant Rem.”) 8. Therefore, it is argued that the amendment overcome Koori which requires high-crystalline and low-crystalline polyolefin materials. Id. The Examiner respectfully disagrees. The polymer of the resin composition C of Koori can be exclusively polypropylene because the resin composition C has general-purpose polypropylene as the high-crystalline polyolefin A and low-crystalline polypropylene as the low-crystalline polyolefin B. See Koori [0035]. Therefore, the resin composition C reads on the “polypropylene resin” because it is a resin of exclusively polypropylene as the polymer component. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to T. BENNETT MCKENZIE whose telephone number is (571)270-5327. The examiner can normally be reached Mon-Thurs 7:30AM-6:00PM. 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, Jennifer Dieterle can be reached at 571-270-7872. 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. T. BENNETT MCKENZIE Primary Examiner Art Unit 1776 /T. BENNETT MCKENZIE/Primary Examiner, Art Unit 1776
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Prosecution Timeline

Feb 06, 2023
Application Filed
Jul 01, 2025
Non-Final Rejection — §102, §103, §112
Aug 28, 2025
Response Filed
Sep 30, 2025
Final Rejection — §102, §103, §112
Nov 03, 2025
Response after Non-Final Action
Nov 18, 2025
Request for Continued Examination
Nov 21, 2025
Response after Non-Final Action
Feb 13, 2026
Non-Final Rejection — §102, §103, §112 (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
57%
Grant Probability
80%
With Interview (+22.9%)
3y 3m
Median Time to Grant
High
PTA Risk
Based on 961 resolved cases by this examiner. Grant probability derived from career allow rate.

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