Prosecution Insights
Last updated: April 19, 2026
Application No. 18/275,421

Biodegradable cellulose-based filter media and facial masks including the same

Non-Final OA §103
Filed
Aug 02, 2023
Examiner
WOLFF, ARIELLE R
Art Unit
3785
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Ahlstrom Oyj
OA Round
1 (Non-Final)
47%
Grant Probability
Moderate
1-2
OA Rounds
3y 3m
To Grant
79%
With Interview

Examiner Intelligence

Grants 47% of resolved cases
47%
Career Allow Rate
82 granted / 173 resolved
-22.6% vs TC avg
Strong +32% interview lift
Without
With
+32.0%
Interview Lift
resolved cases with interview
Typical timeline
3y 3m
Avg Prosecution
46 currently pending
Career history
219
Total Applications
across all art units

Statute-Specific Performance

§101
2.9%
-37.1% vs TC avg
§103
57.4%
+17.4% vs TC avg
§102
13.1%
-26.9% vs TC avg
§112
21.2%
-18.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 173 resolved cases

Office Action

§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 . This action is in response to the filing on 8/2/2023. Since the initial filing, claims 1-75 have been cancelled, claims 76-96 have been added and no claims have been amended. Thus, claims 76-96 are pending in the application. 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) 76-79, 83-86, 88-89 and 96 is/are rejected under 35 U.S.C. 103 as being unpatentable over Parker (US 2020/0063354) in view of Zhang (US 2018/0361287). In regards to claim 76, Parker discloses a biodegradable (paragraph 181) facial mask (paragraph 567-568) comprising a cellulose-based filter media (abstract), wherein the cellulose-based filter media comprises a first phase and a second phase (may be multilayered, paragraph 634-635). While Parker does not disclose wherein the first phase comprises refined cellulose fibers, and wherein the second phase comprises cellulose fibers along with at least one of cellulose-based man-made fibers or non-cellulose man-made fibers, it does teach filtering material made of refined cellulose fibers (paragraph 75) and filtering material made of cellulose fibers alone with at least one of cellulose-based man-made fibers (paragraph 34). Further, Zhang teaches a filter which may be incorporated into a face mask (paragraph 171) with a first and second phase (pre-filter layer 100 and filter layer 220, Fig 2A) wherein the two phases have distinct materials and characteristics (paragraph 29-31). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Parker to have a first and second phase wherein the first phase comprises refined cellulose fibers, and wherein the second phase comprises cellulose fibers along with at least one of cellulose-based man-made fibers or non-cellulose man-made fibers a taught by Parker and Zhang as this would allow each phase of the filter to have tailored properties to suit the needs of the user. In regards to claim 77, Parker in view of Zhang teaches the device of claim 76 and Parker further discloses wherein the filter media is at least 50 % biodegradable, according to EN 13432 and is compostable according to EN13432, ASTM D6400 or ASTM D6868 standards (paragraph 191 and 197). In regards to claim 78, Parker in view of Zhang teaches the device of claim 76. While Parker does not explicitly teach wherein the first phase comprises at least 25 wt% of the refined cellulose fibers, it does teach wherein the filter material comprises at least 25 wt% of the refined cellulose fibers (paragraph 81-82). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Parker wherein the first phase comprises at least 25 wt% of the refined cellulose fibers as taught by Parker as this would provide the desired properties for the specific phase so as to suit the needs of the user. In regards to claim 79, Parker in view of Zhang teaches the device of claim 76. While Parker does not explicitly teach wherein the refined cellulose fibers of the first phase are derived from hardwood pulp, and wherein the refined cellulose fibers of the second phase comprise softwood fibers or annual plant fibers, it does teach that the layers may be formed of hardwood or softwood (paragraph 75). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Parker wherein the refined cellulose fibers of the first phase are derived from hardwood pulp, and wherein the refined cellulose fibers of the second phase comprise softwood fibers as taught by Parker as this would allow the layers to be formed of the materials that best suit the needs of that layer. In regards to claim 83, Parker in view of Zhang teaches the device of claim 76. While Parker does not explicitly teach wherein the cellulose fibers of the second phase comprise refined cellulose fibers, it does teach wherein the fibers are refined cellulose fibers (paragraph 81-82). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Parker wherein the cellulose fibers of the second phase comprise refined cellulose fibers as taught by Parker as this would provide the desired properties for the specific phase so as to suit the needs of the user. In regards to claim 84, Parker in view of Zhang teaches the device of claim 76. While Parker does not explicitly disclose wherein the refined cellulose fibers of the second phase comprise softwood fibers or annual plant fibers, it does teach it does teach that the layers may be formed of hardwood or softwood (paragraph 75). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Parker wherein the refined cellulose fibers of the second phase comprise softwood fibers or annual plant fibers as taught Parker as this would allow the layers to be formed of the materials that best suit the needs of that layer. In regards to claim 85, Parker in view of Zhang teaches the device of claim 76 and Parker further discloses wherein the filter material comprises at least 50 wt% of the refined cellulose fibers (paragraph 81-82). In regards to claim 86, Parker in view of Zhang teaches the device of claim 76. While Parker does not explicitly teach wherein the second phase comprises the following composition: from 30 to 90 wt % of refined cellulose fibers; from 0 to 40 wt % unrefined cellulose-based man-made fibers; from 0 to 25 wt% of cellulose-based man-made fibers; and from 0 to 50 wt% of non-cellulose man-made fibers, it does teach wherein the weight composition of the layers may be altered to suit the needs of the user and may encompass the claimed ranges (paragraph 77-82). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Parker wherein the second phase comprises the following composition: from 30 to 90 wt % of refined cellulose fibers; from 0 to 40 wt % unrefined cellulose-based man-made fibers; from 0 to 25 wt% of cellulose-based man-made fibers; and from 0 to 50 wt% of non-cellulose man-made fibers as taught by Parker as where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). In regards to claim 88, Parker in view of Zhang teaches the device of claim 76 and Zhang further teaches wherein the first phase is thinner than the second phase in the filter media (Fig 2A). In regards to claim 89, Parker in view of Zhang teaches the device of claim 76 and Parker further discloses wherein the filter media is formed via a wet-laid process (abstract). In regards to claim 96, Parker in view of Zhang teaches the device of claim 76 and Parker further disclose wherein the mask is a surgical mask or a civil mask (paragraph 567-568). Claim(s) 80 is/are rejected under 35 U.S.C. 103 as being unpatentable over Parker (US 2020/0063354) in view of Zhang (US 2018/0361287) as applied above and in further view of Hassounah (US 2022/0023784). In regards to claim 80, Parker in view of Zhang teaches the device of claim 76 and Parker further discloses wherein the first phase comprises a basis weight of 4 to 15 gsm and the second phase comprises a basis weight of 10 to 40 gsm (basis weight can be varied from 10 gsm to 750 gsm as needed, paragraph 447 and 556). Parker does not teach wherein the first phase has a thickness 5 µm to 70 µm and the second phase has a thickness 35 µm to 150 µm. However, Hassounah teaches wherein the first phase has a thickness 5 µm to 70 µm and the second phase has a thickness 35 µm to 150 µm (paragraph 40 and 90). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Parker wherein the first phase has a thickness 5 µm to 70 µm and the second phase has a thickness 35 µm to 150 µm as taught by Hassounah as this would provide a thin and light weight construction to suit the user’s comfort. Claim(s) 81 and 82 is/are rejected under 35 U.S.C. 103 as being unpatentable over Parker (US 2020/0063354) in view of Zhang (US 2018/0361287) as applied above and in further view of Falke (DE 202020102548). In regards to claim 81, Parker in view of Zhang teaches the device of claim 76 and Parker further discloses wherein the cellulose- based man-made fibers are present in the second phase and are selected from the group consisting of Lyocell (paragraph 36), fibrillated Lyocell, and viscose fibers (paragraph 95), and wherein the cellulose-based man-made fibers are present and a length of 1 to 20 mm (paragraph 147-148). Parker does not disclose wherein the fibers comprise a fineness of 0.5 to 5 dtex. However, Falke teaches wherein the fibers comprise a fineness of 0.5 to 5 dtex (page 3 last paragraph). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Parker wherein the fibers comprise a fineness of 0.5 to 5 dtex as taught by Falke as this is a known fineness for this purpose. In regards to claim 82, Parker in view of Zhang teaches the device of claim 76 and Parker further discloses wherein the non- cellulose man-made fibers are present in the second phase and are selected from the group consisting of polyesters, co-polyesters, bicomponent polyester/polyolefin, modified polyesters, polyolefin, polyaramids, polyamides, biopolymers, polylactic acids, polybutylene succinates, polybutylene succinate co-adipates, polycaprolactones, polybutyrate adipate terephthalates, and combinations thereof (paragraph 175), and a length of 0.5-15 mm (paragraph 147-148). Parker does not disclose wherein the fibers have a fineness of 0.02 to 1 dtex. However, Falke teaches wherein the fibers have a fineness of 0.02 to 1 dtex (page 3 last paragraph). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Parker wherein the fibers have a fineness of 0.02 to 1 dtex as taught by Falke as this is a known fineness for this purpose. Claim(s) 87 and 91 is/are rejected under 35 U.S.C. 103 as being unpatentable over Parker (US 2020/0063354) in view of Zhang (US 2018/0361287) as evidenced by AFT (https://aft-global.com/sites/default/files/resources/docs/files/2018-11/047-EN%20Freeness%20Conversion%20Table.pdf). In regards to claim 87, Parker in view of Zhang teaches the device of claim 76. While Parker does not explicitly teach wherein the second phase comprises the following composition: from 15 to 45 wt % of first refined cellulose fibers refined to a level from 20°SR to 55°SR; from 15 to 45 wt% of second refined cellulose fibers different from the first refined cellulose fiber refined to a level from 20°SR to 55°SR; from 0 to 40 wt % unrefined cellulose-based man-made fibers; from 0 to 25 wt% of cellulose-based man-made fibers refined to a level of from 50°SR to 85°SR; from 0 to 20 wt% cellulose fibers refined to a level of from 45°SR to 85°SR; and from 0 to 50 wt% of non-cellulose man-made fibers, it does teach wherein the weight composition of the layers may be altered to suit the needs of the user and may encompass the claimed ranges (paragraph 77-82) and wherein the Freeness of the may also be controlled within a range which encompasses the claimed ranges (paragraph 335, 352, 574, 590, see AFT for unit conversions). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Parker wherein the second phase comprises the following composition: from 15 to 45 wt % of first refined cellulose fibers refined to a level from 20°SR to 55°SR; from 15 to 45 wt% of second refined cellulose fibers different from the first refined cellulose fiber refined to a level from 20°SR to 55°SR; from 0 to 40 wt % unrefined cellulose-based man-made fibers; from 0 to 25 wt% of cellulose-based man-made fibers refined to a level of from 50°SR to 85°SR; from 0 to 20 wt% cellulose fibers refined to a level of from 45°SR to 85°SR; and from 0 to 50 wt% of non-cellulose man-made fibers as taught by Parker and evidenced by AFT as this would allow the properties of the layers to be controlled as desired. In regards to claim 91, Parker in view of Zhang teaches the device of claim 76. While Parker does not explicitly teach wherein the cellulose fibers of the second phase comprise refined cellulose fibers, and wherein the cellulose fibers of the first phase or the second phase are refined to a level from 20°SR to 85°SR, it does teach wherein the Freeness of the layers may be controlled within a range which encompasses the claimed ranges (paragraph 335, 352, 574, 590, see AFT for unit conversions). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Parker wherein the cellulose fibers of the second phase comprise refined cellulose fibers, and wherein the cellulose fibers of the first phase or the second phase are refined to a level from 20°SR to 85°SR as taught by Parker and evidenced by AFT as this would allow the properties of the layers to be controlled as desired. Claim(s) 90 is/are rejected under 35 U.S.C. 103 as being unpatentable over Parker (US 2020/0063354) in view of Zhang (US 2018/0361287) as applied above and in further view of Eurofins (https://www.auretitalia.org/wp-content/uploads/2020/04/medical_face_mask_report_v13.pdf). In regards to claim 90, Parker in view of Zhang teaches the device of claim 76. Parker does not disclose wherein the filter media has: a particle filtration efficiency (PFE) of at least 70% at 3 µm, measured using 3µm Di- Ethyl-Hexyl-Sebacat (DEHS) particles; an air permeability of filtration layer of from 200 to 800 L/m2/s (Textest Air Permeability at 196 Pa); a bacterial filtration efficiency (BFE) greater than 50%, according to the EN 14683: 2019, Annex B standard or the ASTM F2101-19 standard; a micro-bacterial cleanliness of< 30 cfu/g according to the EN 14683 standard or ISO 11737-1 standard; and/or a differential pressure less than 60 Pa/cm2, according to the EN 14683:2019, Annex C standard or the ASTM F2100-19 standard. However, Eurofins teaches wherein the filter media has: a bacterial filtration efficiency (BFE) greater than 50%, according to the EN 14683: 2019, Annex B standard or the ASTM F2101-19 standard; a micro-bacterial cleanliness of< 30 cfu/g according to the EN 14683 standard or ISO 11737-1 standard; and/or a differential pressure less than 60 Pa/cm2, according to the EN 14683:2019, Annex C standard or the ASTM F2100-19 standard (Fig 1). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Parker wherein the filter media has: a bacterial filtration efficiency (BFE) greater than 50%, according to the EN 14683: 2019, Annex B standard or the ASTM F2101-19 standard; a micro-bacterial cleanliness of< 30 cfu/g according to the EN 14683 standard or ISO 11737-1 standard; and/or a differential pressure less than 60 Pa/cm2, according to the EN 14683:2019, Annex C standard or the ASTM F2100-19 standard as taught by Eurofins as this is interpreted as alternative limitations and these are known parameters for such purposes so as to provide the best result. Claim(s) 92-95 is/are rejected under 35 U.S.C. 103 as being unpatentable over Parker (US 2020/0063354) in view of Zhang (US 2018/0361287) as applied above and in further view of Busby (US 2022/0118295). In regards to claim 92, Parker in view of Zhang teaches the device of claim 76. Parker does not disclose wherein the filter media is sandwiched between a first layer intended to be in contact with the face of a user when worn and a second layer intended to be in contact with the environment when worn by the user. However, Busby teaches a face mask wherein the filter media is sandwiched between a first layer intended to be in contact with the face of a user when worn and a second layer intended to be in contact with the environment when worn by the user (paragraph 40, Fig 2A and 2B). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Parker wherein the filter media is sandwiched between a first layer intended to be in contact with the face of a user when worn and a second layer intended to be in contact with the environment when worn by the user as taught by Busby as this would provide a comfortable layer to rest against the user’s skin. In regards to claim 93, Parker in view of Zhang and Busby teaches the device of claim 92. While Parker teaches wet laid layers (abstract), it does not disclose wherein the first layer comprises a wet laid fibrous layer. Further, Busby teaches wherein the first layer comprises a wet laid fibrous layer (layers may be made of cellulose acetate, paragraph 9, layers may be formed of we laying process, paragraph 97-98). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Parker wherein the first layer comprises a wet laid fibrous layer as taught by Busby as this is a commonly known method by which to form such layers. In regards to claim 94, Parker in view of Zhang and Busby teaches the device of claim 92. Parker does not teach wherein either or both of first and second layers comprise a spunbond layer, and wherein the spunbond layer comprises a member selected from the group consisting of polypropylene, polyethylene, one or more biopolymers, and combinations thereof. However, Zhang teaches wherein either or both of first and second layers comprise a spunbond layer, and wherein the spunbond layer comprises a member selected from the group consisting of polypropylene, polyethylene, one or more biopolymers, and combinations thereof (paragraph 130-131). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Parker wherein either or both of first and second layers comprise a spunbond layer, and wherein the spunbond layer comprises a member selected from the group consisting of polypropylene, polyethylene, one or more biopolymers, and combinations thereof as taught by Zhang as these are known methods and materials to form mask and filer layers. In regards to claim 95, Parker in view of Zhang and Busby teaches the device of claim 94 and Parker further discloses wherein the one or more biopolymers are presents and are selected from polylactic acids (paragraph 231). Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to Arielle Wolff whose telephone number is (571)272-8727. The examiner can normally be reached Mon-Fri 8:00-4:00. 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, Kendra Carter can be reached at (571) 272-9034. 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. /ARIELLE WOLFF/ Examiner, Art Unit 3785 /KENDRA D CARTER/ Supervisory Patent Examiner, Art Unit 3785
Read full office action

Prosecution Timeline

Aug 02, 2023
Application Filed
Jan 30, 2026
Non-Final Rejection — §103 (current)

Precedent Cases

Applications granted by this same examiner with similar technology

Patent 12569388
Adjustable table and related methods
2y 5m to grant Granted Mar 10, 2026
Patent 12564536
Detachable pneumatic therapeutic apparatus
2y 5m to grant Granted Mar 03, 2026
Patent 12558287
Compression Device Especially for Preventing Deep Vein Thrombosis
2y 5m to grant Granted Feb 24, 2026
Patent 12533480
PATIENT INTERFACE
2y 5m to grant Granted Jan 27, 2026
Patent 12533219
WATERWAY CONTROL DEVICE AND ORAL IRRIGATOR HANDLE
2y 5m to grant Granted Jan 27, 2026
Study what changed to get past this examiner. Based on 5 most recent grants.

AI Strategy Recommendation

Get an AI-powered prosecution strategy using examiner precedents, rejection analysis, and claim mapping.
Powered by AI — typically takes 5-10 seconds

Prosecution Projections

1-2
Expected OA Rounds
47%
Grant Probability
79%
With Interview (+32.0%)
3y 3m
Median Time to Grant
Low
PTA Risk
Based on 173 resolved cases by this examiner. Grant probability derived from career allow rate.

Sign in with your work email

Enter your email to receive a magic link. No password needed.

Personal email addresses (Gmail, Yahoo, etc.) are not accepted.

Free tier: 3 strategy analyses per month