Prosecution Insights
Last updated: April 19, 2026
Application No. 18/280,146

FILTRATION MEMBRANE FROM A BLEND COMPRISING POLYSULFONE AND POLYOXAZOLINE AND METHOD MAKING THEREOF

Non-Final OA §103§112
Filed
Sep 01, 2023
Examiner
MENON, KRISHNAN S
Art Unit
1777
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Solventum Intellectual Properties Company
OA Round
1 (Non-Final)
60%
Grant Probability
Moderate
1-2
OA Rounds
3y 2m
To Grant
71%
With Interview

Examiner Intelligence

Grants 60% of resolved cases
60%
Career Allow Rate
879 granted / 1475 resolved
-5.4% vs TC avg
Moderate +12% lift
Without
With
+11.7%
Interview Lift
resolved cases with interview
Typical timeline
3y 2m
Avg Prosecution
72 currently pending
Career history
1547
Total Applications
across all art units

Statute-Specific Performance

§101
1.7%
-38.3% vs TC avg
§103
31.5%
-8.5% vs TC avg
§102
29.4%
-10.6% vs TC avg
§112
26.4%
-13.6% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1475 resolved cases

Office Action

§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 . Election/Restrictions Claims 19 and 20 are withdrawn from further consideration pursuant to 37 CFR 1.142(b), as being drawn to a nonelected invention, there being no allowable generic or linking claim. Applicant timely traversed the restriction (election) requirement in the reply filed on 12/19/25. Claim Rejections - 35 USC § 112 The following is a quotation of the first paragraph of 35 U.S.C. 112(a): IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention. Claim 15 is rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention. Claim 15 recites the isotropic region as having larger pore size than that of the asymmetric regions. While support for this is in page 3, lines 16-21. The actual reduction to practice or the working example for the claimed membrane is only example 4, which teaches the dual asymmetric structure depicted in figure 4. This has the isotropic region with the lowest pore size as claimed in claim 14. There is no embodiment or example or any details as to how to make the membrane of claim 15. Therefore, applicant does not seem to have possession of the invention at the time of the filing date. 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. Claim 6 is 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. Claim 6: “a modification … of these polymers” is indefinite, since the modification is a vague term, and there are no other details on the modification. 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. Claim(s) 1-18 are rejected under 35 U.S.C. 103 as being unpatentable over Ansorge et al (US 2008/0197072) in view of Hu et al (US 5,178,765.) Ansorge teaches a microporous membrane substantially as claimed, except for blending poly(2-oxazoline) with the polyethersulfone. Ansorge teaches a flat sheet membrane having two asymmetric regions and a separating layer there between. See the abstract and [0011]-[0016]. The membrane is formed from polyether sulfone and PVP. See the working examples. Regarding polyoxazoline, see Hu, which teaches blending poly (2-oxazoline) with polysulfone (abstract) for obtaining exceedingly high strength microfiltration membrane even after alcohol extraction – see Hu, col. 2, lines 34-39. Therefore, it would have been obvious to one of ordinary skill to have polyoxazoline blended with polysulfone for making the Ansorge membrane. Hu teaches this as also known in the art - see col. 2 lines 16-30. Regarding claim 4, since the separating layer is between the two asymmetric regions, it can be considered as either on the first or on the second layer. Claim 5: pore size on the first layer is larger than that of the second layer – see [0014]-[0015]. Claim 6: blend further has PEG – examples. Claim 7: hydrophilic polymer is within the range claimed – examples. Claim 8: PVP is >7% - examples. Claim 9: does not comprise PVP: this is an option available – see alternatives to PVP in [0038]. Claim 10: while the solvents are not patentable elements for the product claim, Ansorge does teach them in the examples. Claim 11: polymer blend is hydrophobic – this would be inherent because Ansorge in view of Hu has the same blend of PES and polyoxazoline. Claim 12: “essentially isotropic region” – see [0013] Claims 13, 14: isotropic region is the separating layer – [0011]: interior of the membrane with minimal pore size, though very thin, would be isotropic as well. Claim 15 – see [0013]-[0014]: pore size pass through maximum on isotropic region and then decreases towards second surface. Notes on claims 13-15: Ansorge membrane structure has an asymmetric region near the first surface, then a narrow pore (separation) region, then pores widens to a larger isotropic region and to the second asymmetric region as seen in [0011]-[0016] Claim 16: elongated pores – while Ansorge is silent on this, it is well-known that the asymmetric membranes have a sponge like structure with finger-shaped pores formed by phase inversion. See the examples: after casting, the membrane is introduced into a coagulation bath to remove solvents and PVP. Also, pores are elongated by their nature – cylindrical or tubular. Claim 17, pore size ratio – see [0015] Claim 18: two membranes stacked in series – while the references are silent on this, having multiple layers of filters in series is commonly practiced to improve filtration efficiency, and is not patentable, unless otherwise shown. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to KRISHNAN S MENON whose telephone number is (571)272-1143. The examiner can normally be reached Flexible, but generally Monday-Friday: 8:00AM-4:30PM. 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, Prem C Singh can be reached at 571-272-6381. 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. /KRISHNAN S MENON/ Primary Examiner, Art Unit 1777
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Prosecution Timeline

Sep 01, 2023
Application Filed
Jan 26, 2026
Non-Final Rejection — §103, §112 (current)

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Prosecution Projections

1-2
Expected OA Rounds
60%
Grant Probability
71%
With Interview (+11.7%)
3y 2m
Median Time to Grant
Low
PTA Risk
Based on 1475 resolved cases by this examiner. Grant probability derived from career allow rate.

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