Prosecution Insights
Last updated: April 19, 2026
Application No. 17/914,254

Air filtration material, device for decontaminating air by filtration and manufacturing method.

Non-Final OA §102§103
Filed
Sep 23, 2022
Examiner
BUI, DUNG H
Art Unit
1773
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Cellulotech Inc.
OA Round
1 (Non-Final)
78%
Grant Probability
Favorable
1-2
OA Rounds
2y 7m
To Grant
99%
With Interview

Examiner Intelligence

Grants 78% — above average
78%
Career Allow Rate
962 granted / 1227 resolved
+13.4% vs TC avg
Strong +24% interview lift
Without
With
+24.4%
Interview Lift
resolved cases with interview
Typical timeline
2y 7m
Avg Prosecution
85 currently pending
Career history
1312
Total Applications
across all art units

Statute-Specific Performance

§103
48.1%
+8.1% vs TC avg
§102
26.8%
-13.2% vs TC avg
§112
18.8%
-21.2% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1227 resolved cases

Office Action

§102 §103
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 . 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. Election/Restrictions Applicant’s election without traverse of Group I and Species A (fig. 2), claims 1-2 and 4-8, in the reply filed on 11/02/25 is acknowledged. 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) 1-2 and 4-8 are rejected under 35 U.S.C. 102(a)(1) as anticipated by or, in the alternative, under 35 U.S.C. 103 as obvious over Gordon (US 41074267). As regarding claim 1, Gordon discloses the claimed invention for a filtering material (fig. 5; col 11 ln 55-63) that is permeable to air and impermeable to human oral, nasal and/or ocular aqueous liquid excretions, comprising: at least one wad, termed a hydrophobic wad, of at least two hydrophobic sheets that are superimposed and each formed by porous paper with a grammage of less than 30 g/m2 (made of a sheet or fabric of cellulose treated on one face or on both faces - such as very thin paper - comparable to a disposable paper handkerchief, particular of the type referred to as a “Kleene@” in the present application - [0065] and [0089]), each hydrophobic sheet being formed by cellulose fibers, termed cross-linked cellulose fibers, bonded together by means of hydrogen bonds and by means of covalent bonds formed with at least one group of cross-linking atoms, wherein at least a portion of the hydroxyls of said cross-linked cellulose fibers that are not involved in the hydrogen bonds and that are accessible to gases form a covalent bond with an acyl group containing a hydrophobic chain (col 4 In 1-34, col 5 In 34-53, col 9 In 9-45, col 11 In 55 - col 12 In 8, and example 1). Alternatively, if Gordon does not disclose a grammage of less than 30 g/m2. It would have been obvious to one having ordinary skill in the art before the effective filing date of the invention was made to provide a grammage of less than 30 g/m2 in order reduce airflow resistance while maintaining effective filtration, provide a lightweight, highly permeable structure with a high surface-area-to-mass ratio, since it has been held that discovering an optimum value of a result effective variable involves only routine skill in the art. In re Boesch, 617 F.2d 272, 205 USPQ 215 (CCPA 1980). Where patentability is said to be based upon particular chosen grammages or upon another variable recited in the claim, the applicant must show that the chosen grammages are critical and unexpected results. As regarding claim 2, Gordon as modified discloses all of limitations as set forth above. Gordon as modified discloses the claimed invention except for wherein said material comprises at least one wad, termed a hydrophilic wad, of at least one sheet formed by porous hydrophilic paper, said at least one sheet of porous hydrophilic paper being formed by cellulose fibers bonded together at least by means of hydrogen bonds; said at least one hydrophobic wad and said at least one hydrophilic wad being superimposed one upon the other in a manner such as to form a stack of superimposed porous sheets that is suitable for a flow of air that is to be filtered to pass through, by which means the air of the flow of air passing through the filtering material is filtered, and; at least one hydrophilic wad forming a free principal face of the stack of superimposed porous sheets, said free principal face being a free face for receiving a flow of air that is to be filtered. It would have been obvious to one having ordinary skill in the art before the effective filing date of the invention was made to provide wherein said material comprises at least one wad, termed a hydrophilic wad, of at least one sheet formed by porous hydrophilic paper, said at least one sheet of porous hydrophilic paper being formed by cellulose fibers bonded together at least by means of hydrogen bonds; said at least one hydrophobic wad and said at least one hydrophilic wad being superimposed one upon the other in a manner such as to form a stack of superimposed porous sheets that is suitable for a flow of air that is to be filtered to pass through, by which means the air of the flow of air passing through the filtering material is filtered, and; at least one hydrophilic wad forming a free principal face of the stack of superimposed porous sheets, said free principal face being a free face for receiving a flow of air that is to be filtered in order to remove moisture from gas streams, capture polar contaminants, since it was known in the art as shown in Okada et al (US 20210315747; hereinafter Okada; [0026], [0115], [0142]). Gordon as modified does not disclose porous hydrophilic paper with a grammage of less than 30 g/m2. It would have been obvious to one having ordinary skill in the art before the effective filing date of the invention was made to provide porous hydrophilic paper with a grammage of less than 30 g/m2 in order reduce airflow resistance while maintaining effective filtration, since it has been held that discovering an optimum value of a result effective variable involves only routine skill in the art. In re Boesch, 617 F.2d 272, 205 USPQ 215 (CCPA 1980). Where patentability is said to be based upon particular chosen grammages or upon another variable recited in the claim, the applicant must show that the chosen grammages are critical and unexpected results. As regarding claim 4, Gordon as modified discloses all of limitations as set forth above. Gordon as modified discloses the claimed invention except for wherein at least two sheets of said hydrophobic wad are assembled by means of at least one material, termed the assembly material, which is a permeable solid comprising at least one thermoplastic polymer. It would have been obvious to one having ordinary skill in the art before the effective filing date of the invention was made to provide wherein at least two sheets of said hydrophobic wad are assembled by means of at least one material, termed the assembly material, which is a permeable solid comprising at least one thermoplastic polymer in order to remove moisture from gas streams, capture polar contaminants, since it was known in the art as shown in Smith et al (US 20170312673; hereinafter Smith; [0079] – bicomponent binder fiber). As regarding claim 5, Gordon as modified discloses all of limitations as set forth above. Gordon as modified discloses the claimed invention for wherein at least one thermoplastic polymer is selected from the group formed by polyethylenes, polypropylenes, polyamides and poly-L-lactic acids (Smith – [0061]). As regarding claim 6, Gordon as modified discloses all of limitations as set forth above. Gordon as modified discloses the claimed invention for wherein the thermoplastic polymer extends only at the peripheral border of the stack of superimposed porous sheets (Smith – [0111]). Alternatively, it would have been obvious to one having ordinary skill in the art before the effective filing date of the invention was made to provide wherein the thermoplastic polymer extends only at the peripheral border of the stack of superimposed porous sheets in order to enhance filtering material in order to ensure mechanical cohesion of the superimposed porous sheets while preserving porosity, permeability, and chemical functionality in the active filtering zone, since it has been held that rearranging parts of an invention involves only routine skill in the art. In re Japikse, 86 USPQ 70. As regarding claim 7, Gordon as modified discloses all of limitations as set forth above. Gordon as modified discloses the claimed invention for wherein at least one acyl group containing a hydrophobic chain is selected from the group formed by a palmityl group, a stearyl group and a behenyl group. It would have been obvious to one having ordinary skill in the art before the effective filing date of the invention was made to provide wherein at least two sheets of said hydrophobic wad are assembled by means of at least one material, termed the assembly material, which is a permeable solid comprising at least one thermoplastic polymer in order to remove moisture from gas streams, capture polar contaminants, since it was known in the art as shown in Kozlov et al (US 20160272676; hereinafter Kozlov; [0014]). As regarding claim 8, Gordon as modified discloses all of limitations as set forth above. Gordon as modified discloses the claimed invention for wherein each sheet of the stack of superimposed porous sheets is formed by a portion of the thickness of a disposable paper tissue (very thin paper – comparable to a disposable paper handkerchief). Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to DUNG H BUI whose telephone number is (571)270-7077. The examiner can normally be reached Monday-Friday 8:00 - 4:30 ET. 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. /DUNG H BUI/ Primary Examiner, Art Unit 1773
Read full office action

Prosecution Timeline

Sep 23, 2022
Application Filed
Dec 16, 2025
Non-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

1-2
Expected OA Rounds
78%
Grant Probability
99%
With Interview (+24.4%)
2y 7m
Median Time to Grant
Low
PTA Risk
Based on 1227 resolved cases by this examiner. Grant probability derived from career allow rate.

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