Prosecution Insights
Last updated: April 19, 2026
Application No. 17/776,799

FILTRATION COMPOSITES

Non-Final OA §DP
Filed
May 13, 2022
Examiner
MCCULLOUGH, ERIC J.
Art Unit
1773
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Donaldson Company Inc.
OA Round
3 (Non-Final)
30%
Grant Probability
At Risk
3-4
OA Rounds
4y 2m
To Grant
74%
With Interview

Examiner Intelligence

Grants only 30% of cases
30%
Career Allow Rate
120 granted / 393 resolved
-34.5% vs TC avg
Strong +43% interview lift
Without
With
+43.4%
Interview Lift
resolved cases with interview
Typical timeline
4y 2m
Avg Prosecution
45 currently pending
Career history
438
Total Applications
across all art units

Statute-Specific Performance

§101
0.6%
-39.4% vs TC avg
§103
55.3%
+15.3% vs TC avg
§102
13.9%
-26.1% vs TC avg
§112
23.1%
-16.9% vs TC avg
Black line = Tech Center average estimate • Based on career data from 393 resolved cases

Office Action

§DP
DETAILED ACTION This action is in response to the RCE with amendments and remarks dated 02/25/2026, in which claims 1-7, 9 and 11-17 are pending and ready for examination. 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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 02/25/2026 has been entered. Election/Restrictions Claims 1-7, 9, 11-12 and 16-17 are directed to an allowable product. Pursuant to the procedures set forth in MPEP § 821.04(B), claims 13-15, directed to the process of making or using an allowable product, previously withdrawn from consideration as a result of a restriction requirement, claims 13-15 are hereby rejoined and fully examined for patentability under 37 CFR 1.104. Because all claims previously withdrawn from consideration under 37 CFR 1.142 have been rejoined, the restriction requirement as set forth in the Office action mailed on 12/20/2024 is hereby withdrawn. In view of the withdrawal of the restriction requirement as to the rejoined inventions, applicant(s) are advised that if any claim presented in a divisional application is anticipated by, or includes all the limitations of, a claim that is allowable in the present application, such claim may be subject to provisional statutory and/or nonstatutory double patenting rejections over the claims of the instant application. Once the restriction requirement is withdrawn, the provisions of 35 U.S.C. 121 are no longer applicable. See In re Ziegler, 443 F.2d 1211, 1215, 170 USPQ 129, 131-32 (CCPA 1971). See also MPEP § 804.01. Information Disclosure Statement The information disclosure statement(s) (IDS) submitted on 25 FEBRUARY 2026 is/are in compliance with the provisions of 37 CFR 1.97 and has/have been considered. An initialed copy of Form 1449 is enclosed herewith. Allowable Subject Matter The following is a statement of reasons for the indication of allowable subject matter: Applicant's arguments filed 02/25/2026 have been fully considered and they are persuasive. While Nagy discloses a multi-layer composite filter which may have first, second and third nonwoven filtration mediums and a substrate which are broadly disclosed to possibly include the same fiber components as claimed, Nagy discloses a broad range of fiber types, diameters, lengths and their respective concentrations which make up a variety of different layers, and Nagy does not provide guidance that would lead one of ordinary skill in the art to pick the specific combinations as claimed. Further, the previous 35 U.S.C. 112(b) rejections of claims 1-7, 9 and 11-17 are withdrawn in view of the Applicants’ arguments and amendments. Thus claims 1-7, 9 and 11-17 contain allowable subject matter; but remain rejected under Obvious-type Double Patenting, see the rejection below. As allowable subject matter has been indicated, applicant's reply must either comply with all formal requirements or specifically traverse each requirement not complied with. See 37 CFR 1.111(b) and MPEP § 707.07(a). Double Patenting Claims 1-7, 9 and 11-17 are provisionally rejected on the ground of nonstatutory double patenting as being unpatentable over claims 3-4, 6, 16-17, and 19-32 of copending Application No. 17/776,901. Application ‘901 discloses a nonwoven filter media (i.e. a composite) comprising first, second and third nonwoven filter media, having the same component fibers as presently claimed, and with weight percentages which are the same or overlap those claimed. Claim 26 of Application ‘901 further discloses a scrim layer, i.e. a support layer. While Application ‘901 does not disclose the order of layers, it is seen as therefore obvious to order them in any order, including that as claimed. While Application ‘901 does not disclose the first and second nonwovens act as loading layers and the third as an efficiency layer, these limaitons are functional limitations, and as they have the same components, they would obviously function the same as claimed. Claims directed to an apparatus must be distinguished from the prior art in terms of structure rather than function (see MPEP 2114). While Application ‘901 does not disclose each of the nonwoven filtration media are discrete layers, as they are not disclosed to be otherwise it would have been obvious that they are discrete layers. While Application ‘901 does not disclose the thickness of the first and second nonwoven media, it is old and well-known that filter media thickness effects the resulting properties of the filter media, sch as dust holding capacity, or resistance to fluid flow, and therefore thickness is a variable which achieves a recognized result, and it would therefore have been obvious for one of skill in the art to optimize this variable through routine experimentation, by using values including those within the scope of the present claims, so as to produce desired end results. See MPEP § 2144.05 (B). This is a provisional nonstatutory double patenting rejection. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to Eric J. McCullough whose telephone number is (571)272-8885. The examiner can normally be reached Monday-Friday 10:00-6:00. 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, Benjamin L Lebron can be reached at 571-272-0475. 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. /ERIC J MCCULLOUGH/ Examiner, Art Unit 1773 /BENJAMIN L LEBRON/ Supervisory Patent Examiner, Art Unit 1773
Read full office action

Prosecution Timeline

May 13, 2022
Application Filed
Feb 22, 2025
Non-Final Rejection — §DP
May 23, 2025
Response Filed
Aug 22, 2025
Final Rejection — §DP
Feb 25, 2026
Request for Continued Examination
Mar 04, 2026
Response after Non-Final Action
Mar 21, 2026
Non-Final Rejection — §DP (current)

Precedent Cases

Applications granted by this same examiner with similar technology

Patent 12595396
ACID RESISTANT FILTER MEDIA
2y 5m to grant Granted Apr 07, 2026
Patent 12533640
POLYTETRAFLUOROETHYLENE COMPOSITE FILTER MATERIAL AND PREPARATION METHOD AND USES THEREOF
2y 5m to grant Granted Jan 27, 2026
Patent 12528050
BIOCIDE COMPOSITION AND METHOD
2y 5m to grant Granted Jan 20, 2026
Patent 12528723
PLASMA ACTIVATED WATER PRODUCTION WITH MEMBRANE CONCENTRATION
2y 5m to grant Granted Jan 20, 2026
Patent 12497737
Filter Media
2y 5m to grant Granted Dec 16, 2025
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
30%
Grant Probability
74%
With Interview (+43.4%)
4y 2m
Median Time to Grant
High
PTA Risk
Based on 393 resolved cases by this examiner. Grant probability derived from career allow rate.

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