Prosecution Insights
Last updated: April 19, 2026
Application No. 18/548,367

METHOD FOR FRACTIONATION OF HIGHLY REFINED CELLULOSE

Non-Final OA §103
Filed
Aug 30, 2023
Examiner
CALANDRA, ANTHONY J
Art Unit
1748
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Stora Enso OYJ
OA Round
1 (Non-Final)
63%
Grant Probability
Moderate
1-2
OA Rounds
3y 0m
To Grant
80%
With Interview

Examiner Intelligence

Grants 63% of resolved cases
63%
Career Allow Rate
638 granted / 1014 resolved
-2.1% vs TC avg
Strong +18% interview lift
Without
With
+17.5%
Interview Lift
resolved cases with interview
Typical timeline
3y 0m
Avg Prosecution
62 currently pending
Career history
1076
Total Applications
across all art units

Statute-Specific Performance

§101
1.1%
-38.9% vs TC avg
§103
39.9%
-0.1% vs TC avg
§102
21.0%
-19.0% vs TC avg
§112
26.7%
-13.3% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1014 resolved cases

Office Action

§103
Detailed Office Action The communication dated 12/2/2025 has been entered and fully considered. Claims 1-16 and 18 are pending with claims 16 and 18 withdrawn from consideration. 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 Interpretation and allowable subject matter Claim 7 is objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims. In claim 7 it is stated that the fine fraction can pass through a 200-mesh screen. The Examiner interprets this to be substantially all the fine fraction and only allowing a de minimis amount not passing through the screen. The prior art GILKEY (cited below) discloses a 0.175 mm-hole size which is equivalent to an 80 mesh. It would not meet the claim language because there would be a substantial amount of fines and particles above the 200-mesh size which would not pass through. Election/Restriction In the 10/23/2025 restriction the Examiner grouped claim 15 as part of group II and claim 16 as part of group III. Claim 15 should be part of group I, claim 16 as part of group II, and claim 18 as part of group III. Claim 15 is therefore being examined with group I and the restriction to claim 15 is withdrawn. Claims 16 and 18 remain withdrawn without traverse. 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. This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention. Claims 1-6 and 8-15 are rejected under 35 U.S.C. 103 as being unpatentable over U.S. 5,133,832 GILKEY in view of The World of Market Pulp by NANKO et al., hereinafter NANKO. As for claim 1-3 and 6, GILKEY discloses taking deinked papermaking stock and fractionating the deinked papermaking stock on a belt filter [abstract]. The fraction is separated into long fibers as a dewatered retentate and short fibers in a filtrate [col. 1 lines]. GILKEY discloses that that the filtrate can comprise percent of the total solids. GILKEY discloses that a 50%-50% fines/long fiber split)and that substantially all long fibers are maintained [col. 3 lines 24-26]. GILKEY discloses a feed consistency of 1% and a retained consistency of 5% [col. 4 lines 30-40]. This means that the 20% of the suspension which doesn’t pass through still contains the fines. Therefore about 40% of the total which passes through [50% fines* 80% liquid pass through = 40%]. The total amount that passes through can be optimized based on the hole size of the wire, the stock fed to the fractionator and the consistency from the fractionator. GILKEY does not disclose the SR of the pulp or the content of fibers having a length of greater than 7 million fibers per gram [pg. 222 Fiber Morphology]. NANKO discloses an example recycled pulp which has a population of 12.6 million fibers per gram and a Canadian standard freeness of between 360 to 190 (SR of about 35 to 52) which overlaps the instant claimed ranges [pg. 223 PFI Table]. NAKNO has 13.8% britt jar fines which will pass through at least the same rate as the fines of GILKEY (13.8*0.8 =10.72%). At the time of the invention it would be obvious to the person of ordinary skill in the art to substitute one known recycled paper source for another known recycled paper source [MPEP 2144.06 (II)]. The person of ordinary skill in the art would expect success as the process of GILKEY does not limit the type of recycled paper that may be treated. As for claims 4 and 5, GILKEY discloses a feed consistency of 1% and a retained consistency of 5% [col. 4 lines 30-40] which means 80% of the suspension passes through. As for claim 8, GILKEY discloses the speed of the device is 3,000 ft/min or 914 m/min which falls within the claimed range [col. 3 lines 45-50]. This is much higher than the claimed apparatus. This suggests that a much higher flow of liquid can through the belt. The mesh further has hole sizes of 0.175 mm squared [col. 3 lines 20-25] which means the holes (~80 mesh) are bigger than the 200-mesh hole fractionation claimed; bigger holes mean bigger flow. Therefore it is the Examiner’s position that the belt of GILKEY has an air permeability greater than 4,000m2/m2/hour. As for claim 9, GILKEY discloses the speed of the device is 3,000 ft/min or 914 m/min which falls within the claimed range [col. 3 lines 45-50]. As for claim 10, GILKEY discloses a belt speed of 914 m/min which is much higher than the instant claimed belt speed which suggests a much lower residence time. In the alternative it would be obvious to optimize the residence time through routine experimentation. The person of ordinary skill in the art would look to have a lower residence time as this would increase the production rate. As for claim 11, the belt fractionator is a single-wire device with belt (25) [Figure 2] As for claim 12, GILKEY discloses that the fines can be recombined after separation and treatments [Figure 1]. As for claims 13-15, some of the fines will be lost to the floatation froth of the flotation cells (50) and therefore less fines will be reintroduced during recombination [Figure 1]. As less fines are added it would be excepted that the SR and the WRV would change in substantially the same way. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to ANTHONY J CALANDRA whose telephone number is (571)270-5124. The examiner can normally be reached Monday-Friday 7:45 AM -4:15 PM. 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, Abbas Rashid can be reached at (571)270-7457. 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. ANTHONY J. CALANDRA Primary Examiner Art Unit 1748 /Anthony Calandra/ Primary Examiner, Art Unit 1748
Read full office action

Prosecution Timeline

Aug 30, 2023
Application Filed
Jan 23, 2026
Non-Final Rejection — §103 (current)

Precedent Cases

Applications granted by this same examiner with similar technology

Patent 12601114
A HIGH YIELD COOKING METHOD
2y 5m to grant Granted Apr 14, 2026
Patent 12601112
MATERIAL STORAGE APPARATUS, METHOD OF CONTROLLING MATERIAL STORAGE APPARATUS, AND SHEET MANUFACTURING APPARATUS
2y 5m to grant Granted Apr 14, 2026
Patent 12595627
MULTILAYER FILM COMPRISING HIGHLY REFINED CELLULOSE FIBERS
2y 5m to grant Granted Apr 07, 2026
Patent 12590411
PAPER PULP, A METHOD FOR PRODUCING PAPER PULP, AND PAPER PULP PRODUCTS
2y 5m to grant Granted Mar 31, 2026
Patent 12590414
PAPER AND PULP FOAM CONTROL AGENT
2y 5m to grant Granted Mar 31, 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
63%
Grant Probability
80%
With Interview (+17.5%)
3y 0m
Median Time to Grant
Low
PTA Risk
Based on 1014 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