Prosecution Insights
Last updated: April 19, 2026
Application No. 17/909,165

ONE STAGE METHOD FOR ACID METAL REMOVAL AND BLEACH

Non-Final OA §103
Filed
Sep 02, 2022
Examiner
KHAN, AMINA S
Art Unit
1761
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Circulose AB
OA Round
3 (Non-Final)
48%
Grant Probability
Moderate
3-4
OA Rounds
3y 4m
To Grant
91%
With Interview

Examiner Intelligence

Grants 48% of resolved cases
48%
Career Allow Rate
484 granted / 1008 resolved
-17.0% vs TC avg
Strong +43% interview lift
Without
With
+43.2%
Interview Lift
resolved cases with interview
Typical timeline
3y 4m
Avg Prosecution
66 currently pending
Career history
1074
Total Applications
across all art units

Statute-Specific Performance

§101
0.5%
-39.5% vs TC avg
§103
62.2%
+22.2% vs TC avg
§102
11.1%
-28.9% vs TC avg
§112
17.2%
-22.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1008 resolved cases

Office Action

§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 . 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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 February 25, 2026 has been entered. Claims 1,2,4,5 and 7-14 are pending. Claims 3 and 6 have been cancelled. Claims 1,2 and 4 have been amended. The rejection of Claims 1 and 7-14 under 35 U.S.C. 103 as being unpatentable over Sperger (WO 2016/123643) in view of Weilach (WO 2015/077807) is withdrawn in view of applicant’s amendments to the claims. Claims 1,2,4,5 and 7-14 stand rejected under 35 U.S.C. 103 as being unpatentable over Sperger (WO 2016/123643) in view of Weilach (WO 2015/077807) and further in view of Umemoto (US 2013/0338250) for the reasons set forth below. Claims 1,2,4,5 and 7-14 stand rejected under 35 U.S.C. 103 as being unpatentable over Sperger (WO 2016/123643) in view of Umemoto (US 2013/0338250) for the reasons set forth below. 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. Claims 1,2,4,5 and 7-14 are rejected under 35 U.S.C. 103 as being unpatentable over Sperger (WO 2016/123643) in view of Weilach (WO 2015/077807) and further in view of Umemoto (US 2013/0338250). Sperger teaches a method of pretreating reclaimed cellulose fibers to be used in production of molded bodies comprising one stage pretreatment with a pretreatment composition containing an acid washing agent, complexing agent and a dye decolorizing agent, which meets the claimed limitation of one stage acid metal removal and acid bleaching, (page 6, line 25-page 7, line 20). Sperger teaches the acid wash is performed at pH 1.5 and 5 at room temperature to 100°C for 15 to 120 min, preferably pH 2-3 at 50-70°C for 15 to 60 min (page 7, lines 1-5). Sperger teaches metal removal can also be accomplished with a complexing agent at room temperature to 100°C for 15 to 120 min, preferably at 50-80°C for 15 to 90 min (page 7, lines 7-13). Sperger teaches the production of molded bodies from the regenerated cellulose is carried out by a viscose or modal process (page 7, lines 22-30; page 4, lines 17-20). Only one acid chemical metal removal step is required in the process. Sperger does not specify oxidative bleaching or acetic acid. Weilach teaches when pretreating reclaimed cellulose to remove metal content and oxidatively bleach, the bleaching can be effectively accomplished hydrogen peroxide or ozone bleaching (page 10). Weilach teaches the fibers are then used to make a molded body by the lyocell or viscose process (page 9, lines 4-7). Umemoto teaches when processing cellulose fibers oxidative bleaching is achieved by treating the cellulose fibers with ozone or peroxide in the presence of an acidic solution which can remove the metal compound, and wherein the acetic acid can be included in the oxidative bleaching step (paragraphs 0081, 0090). It would have been obvious to one of ordinary skill in the art at the time the invention was made to modify the methods of Sperger by incorporating the oxidative bleaching with hydrogen peroxide or ozone as Weilach teaches this method of bleaching is effectively used in pretreating reclaimed cellulose to remove metal content and bleach. Using known effective bleaching agents in methods that invite the inclusion of decolorizing the same cellulose in the same process is obvious. It would have been obvious to one of ordinary skill in the art at the time the invention was made to modify the methods of Sperger and Weilach by oxidatively bleaching the cellulosic fibers in the presence of an acid such as acetic acid and oxidizing agents such as hydrogen peroxide, ozone and peracetic acid as Umemoto teaches using aqueous acid solutions to removes metals which can deteriorate or reduce efficiency of the oxidizing reaction from the oxidizing agent and acetic acid is added to ozone for the benefit of additional oxidizing. It is noted sulfuric acid and hydrochloric acids are alternate embodiments and do not need to be present. The comprising language of the claims allows for the presence of additional acid such as hydrochloric acid. Acids such as hydrochloric acid can be selected instead of sulfuric acid to remove metals and acetic acid can be added in addition to the hydrochloric acid during oxidative bleaching. While Umemoto does not specify that acetic acid removes metals, this would be an expected property of the interaction of the same acid with the same fiber composition containing the same oxidative bleaches. It is elementary that the mere recitation of a newly discovered function or property, inherently possessed by things in the prior art does not cause a claim drawn to distinguish over the prior art. Additionally where the Patent Office has reason to believe that a functional limitation asserted to be critical for establishing novelty in the claimed subject matter may, in fact, be an inherent characteristic of the prior art, it possesses the authority to require the applicant to prove that the subject matter shown to be in the prior art does not possess the characteristic relied on." In re Swinehart, 169 USPQ 226 (CCPA 1971). Sperger invites the inclusion of combined decoloring and metal removal, Weilach teaches oxidative bleaching as a bleaching technique for bleaching reclaimed cellulose with the claimed bleaching agents and Umemoto teaches oxidative bleaching with the claimed bleaching agents in the presence of the claimed acids is effective as the acids remove any residual metals that can reduce the efficiency of the bleaching agents during cellulose fiber processing. Claims 1,2,4,5 and 7-14 are rejected under 35 U.S.C. 103 as being unpatentable over Sperger (WO 2016/123643) in view of Umemoto (US 2013/0338250). Sperger teaches a method of pretreating reclaimed cellulose fibers to be used in production of molded bodies comprising one stage pretreatment with a pretreatment composition containing an acid washing agent, complexing agent and a decolorizing agent, which meets the claimed limitation of one stage acid metal removal and acid bleaching, (page 6, line 25-page 7, line 20). Sperger teaches the acid wash is performed at pH 1.5 and 5 at room temperature to 100°C for 15 to 120 min, preferably pH 2-3 at 50-70°C for 15 to 60 min (page 7, lines 1-5). Sperger teaches metal removal can also be accomplished with a complexing agent at room temperature to 100°C for 15 to 120 min, preferably at 50-80°C for 15 to 90 min (page 7, lines 7-13). Sperger teaches the production of molded bodies from the regenerated cellulose is carried out by a viscose or modal process (page 7, lines 22-30; page 4, lines 17-20). Only one acid chemical metal removal step is required in the process. Sperger does not specify oxidative bleaching or the acetic acids and bleaching agents. Umemoto teaches when processing cellulose fibers oxidative bleaching is achieved by treating the cellulose fibers with ozone or peroxide in the presence of an acid to remove the metal compound, and wherein acetic acid is present (paragraphs 0081,0086,0090). It would have been obvious to one of ordinary skill in the art at the time the invention was made to modify the methods of Sperger by oxidatively bleaching the cellulosic fibers in the presence of an acid such as hydrochloric and acetic acids and oxidizing agents such as hydrogen peroxide, ozone and peracetic acid as Umemoto teaches selection of hydrochloric removes metals which can deteriorate or reduce efficiency of the oxidizing reaction from the oxidizing agent and acetic acid is added to ozone for the benefit of additional oxidizing. It is noted sulfuric acid is only one possibility and does not need to be present. Acids such as hydrochloric acid can be selected instead of sulfuric acid to remove metals and acetic acid can be added in addition to the hydrochloric acid during oxidative bleaching. Applicant’s “comprising” language regarding the ”single aqueous treatment liquor” permits the presence of acids in addition to acetic acid such as hydrochloric acid. Further applicant’s claim does not require that acetic acid is the metal removing agent, rather just that it is present in the treatment liquor. Umemoto teaches broadly that acid solutions can be used to remove metal, and lists as non-limiting examples three strong acids. Umemoto does not recite that weak acids are prohibited or do not remove metal. It is expected the acetic acid presence will also remove metal as it is an acidic solution and combining the same acids with the same oxidizing bleaches in a single composition to the same reclaimed cellulose would inherently produce the same benefit of removing metal even if it is not explicitly recited by the prior art. It is elementary that the mere recitation of a newly discovered function or property, inherently possessed by things in the prior art does not cause a claim drawn to distinguish over the prior art. Additionally where the Patent Office has reason to believe that a functional limitation asserted to be critical for establishing novelty in the claimed subject matter may, in fact, be an inherent characteristic of the prior art, it possesses the authority to require the applicant to prove that the subject matter shown to be in the prior art does not possess the characteristic relied on." In re Swinehart, 169 USPQ 226 (CCPA 1971). Response to Arguments Applicant's arguments filed regarding Sperger in view of Weilach or Umemoto have been fully considered but they are not persuasive. The examiner argues that applicant’s claims are carried out in an aqueous liquor “comprising” a weak acid and an oxidative bleaching agent. The comprising language allows for the presence of additional strong acids such as hydrochloric acid added to the weak acetic acid. Umemoto teaches that hydrochloric acid or acetic acid can be added in the oxidation stage, so either can be added. This teaching allows for the presence of the oxidative bleach and acetic acid. While the prior art may not specify acetic acid as a metal removal agent, it would be expected to have this property as this is an inherent property of the interaction of the acetic acid with the metal compound containing cellulose even if that property is not explicitly recited by the prior art. Further Umemoto teaches acidic aqueous solutions remove metal ions and exemplifies species “such as” dilute sulfuric, hydrochloric and nitric acid but teaches these only as examples which are not limiting. Umemoto in the broader teaching of “acidic aqueous solutions” does not teach these acids can only be strong acids. Applicant’s step of a single stage treatment of acetic acid and oxidative bleaching agent applied to reclaimed cellulose fibers is met by the teachings of the prior art, even if the acetic acid is not explicitly recited as the metal removal agent. Its presence would inherently serve the metal removal function and applicant’s claims recite that acetic acid is present not that it is the metal removing agent and not that it cannot be used in combination with other strong metal removing acids. It is elementary that the mere recitation of a newly discovered function or property, inherently possessed by things in the prior art does not cause a claim drawn to distinguish over the prior art. Additionally where the Patent Office has reason to believe that a functional limitation asserted to be critical for establishing novelty in the claimed subject matter may, in fact, be an inherent characteristic of the prior art, it possesses the authority to require the applicant to prove that the subject matter shown to be in the prior art does not possess the characteristic relied on." In re Swinehart, 169 USPQ 226 (CCPA 1971). It is the examiner’s position that the prior art teaches combining acetic acid and oxidizing bleaching agents in a single stage to reclaimed cellulose fibers. Accordingly, the rejections are maintained. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to AMINA S KHAN whose telephone number is (571)272-5573. The examiner can normally be reached Monday-Friday, 9am-5:30pm EST. 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, Angela Brown-Pettigrew can be reached at 571-272-2817. 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. /AMINA S KHAN/Primary Examiner, Art Unit 1761
Read full office action

Prosecution Timeline

Sep 02, 2022
Application Filed
Jul 17, 2025
Non-Final Rejection — §103
Sep 23, 2025
Response Filed
Dec 07, 2025
Final Rejection — §103
Jan 14, 2026
Response after Non-Final Action
Feb 25, 2026
Request for Continued Examination
Feb 26, 2026
Non-Final Rejection — §103
Feb 26, 2026
Response after Non-Final Action

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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
48%
Grant Probability
91%
With Interview (+43.2%)
3y 4m
Median Time to Grant
High
PTA Risk
Based on 1008 resolved cases by this examiner. Grant probability derived from career allow rate.

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