Prosecution Insights
Last updated: April 19, 2026
Application No. 18/341,805

METHOD FOR TREATING WASTE PLASTIC BASED ON PERSULFATE SYSTEM

Non-Final OA §103§112
Filed
Jun 27, 2023
Examiner
RIETH, STEPHEN EDWARD
Art Unit
1759
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Tianjin University
OA Round
1 (Non-Final)
44%
Grant Probability
Moderate
1-2
OA Rounds
3y 3m
To Grant
77%
With Interview

Examiner Intelligence

Grants 44% of resolved cases
44%
Career Allow Rate
283 granted / 637 resolved
-20.6% vs TC avg
Strong +32% interview lift
Without
With
+32.5%
Interview Lift
resolved cases with interview
Typical timeline
3y 3m
Avg Prosecution
64 currently pending
Career history
701
Total Applications
across all art units

Statute-Specific Performance

§101
0.6%
-39.4% vs TC avg
§103
38.8%
-1.2% vs TC avg
§102
15.9%
-24.1% vs TC avg
§112
30.2%
-9.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 637 resolved cases

Office Action

§103 §112
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 Rejections - 35 USC § 112 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. The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph: The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention. Claims 8 and 10 are 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 8 appears to a combination of three different claims (labelled 8, 9, and 10), whereby “9” and “10” differ from claims 9 and 10, additionally presented after claim 8. It is unclear whether only the limitations of “claim 8” are required or all limitations listed are required. Accordingly, the intended scope of the claim is unclear. As claim 10 depends from claim 8, claim 10 is rejected for the same issues discussed above. The following is a quotation of 35 U.S.C. 112(d): (d) REFERENCE IN DEPENDENT FORMS.—Subject to subsection (e), a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers. The following is a quotation of pre-AIA 35 U.S.C. 112, fourth paragraph: Subject to the following paragraph [i.e., the fifth paragraph of pre-AIA 35 U.S.C. 112], a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers. Claim 10 is rejected under 35 U.S.C. 112(d) or pre-AIA 35 U.S.C. 112, 4th paragraph, as being of improper dependent form for failing to further limit the subject matter of the claim upon which it depends, or for failing to include all the limitations of the claim upon which it depends. To the extent all listed limitations under “claim 8” are required, the limitation “wherein the reaction is performed at a temperature of 80-140 °C” of claim 10 is already present within claim 8. Therefore, claim 10 fails to further limit the subject matter of the claim upon which it depends. Applicant may cancel the claim(s), amend the claim(s) to place the claim(s) in proper dependent form, rewrite the claim(s) in independent form, or present a sufficient showing that the dependent claim(s) complies with the statutory requirements. 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. Claim(s) 1-5 and 9 is/are rejected under 35 U.S.C. 103 as being unpatentable over Hu (ACS EST Engg. 2022, 2, 110-120) in view of Liu (Chemosphere 2022, 298, 134220). Regarding Claims 1-4, Hu teaches methods of treating waste plastic comprising mixing waste plastic such as polyethylenes or polyethylene terephthalate (PET), sulfuric acid, ferrous sulfate, hydrogen peroxide, and water to obtained a mixed solution, and then allowing a reaction of the mixed solution (Page 111; Right Column). Hu differs from the subject matter claimed in that peroxymonosulfate oxidant is not used. Liu also pertains to the oxidative treating of waste plastics using peroxides (Abstract) and teaches it was known in the art either hydrogen peroxide or potassium peroxymonosulfate in combination of Fe2+ are useful systems for treating plastics (Sections 2.1 and 2.2). In view of such, it would have been obvious to one of ordinary skill in the art to substitute hydrogen peroxide with other oxidants such as potassium peroxymonosulfate, thereby predictably affording the oxidative degradation of plastics in accordance with the teachings of Liu. Regarding Claims 5 and 9, Hu teaches the treatment of 1 g / L of plastic (Page 111; Right Column). Claim(s) 6-8 and 10 is/are rejected under 35 U.S.C. 103 as being unpatentable over Hu (ACS EST Engg. 2022, 2, 110-120) in view of Liu (Chemosphere 2022, 298, 134220) and Ghanbari (Chemical Engineering Journal 2017, 310, 41-62). The discussion regarding Hu and Liu within ¶ 14-16 is incorporated herein by reference. Regarding Claim 6, Hu/Liu differs from the subject matter claimed in that a preferred content of sulfuric acid is not described. Ghanbari describes general knowledge concerning oxidative treatments using peroxymonosulfates (Abstract). Ghanbari teaches it was known pH plays an important role in the reaction, whereby acidic conditions promotes efficiency, but strongly acidic conditions (< 3.0) reduces efficiency owing to a drop of Fe2+ availability and radical scavenging (Section 2.2). Accordingly, Ghanbari teaches the level of acidity is a known result effective variable subject to routine optimization by one of ordinary skill in the art. See MPEP 2144.05(II). Case law holds that “discovery of an optimum value of a result effective variable in a known process is ordinarily within the skill of the art.” See In re Boesch, 617 F.2d 272, 205 USPQ 215 (CCPA 1980). In view of this, it would have been obvious to one of ordinary skill in the art to discover workable/optimal sulfuric acid contents within the scope of the present claims so as to produce desirable acidities, such as to achieve optimal oxidation efficiency while avoiding a drop in Fe2+ availability and radical scavenging. Regarding Claim 7, Hu teaches the use of 4 mmol/L of ferrous sulfate (Page 111; Right Column). Regarding Claims 8 and 10, Hu teaches reacting at 140 degrees C for roughly 6-18 hr (Figure 1), which overlaps the claimed range. It would have been obvious to one of ordinary skill in the art to use a range within the claimed range because a reference may be relied upon for all that it would have reasonably suggested to one having ordinary skill the art and Hu suggests the claimed range. A person of ordinary skill would be motivated to use the claimed amount, based on the teachings of Hu. See MPEP 2123. Hu/Liu differs from the subject matter claimed in that a preferred content of peroxymonosulfate is not described. Ghanbari describes general knowledge concerning oxidative treatments using peroxymonosulfates (Abstract). Ghanbari teaches it was known in the art peroxymonosulfate and catalyst dosages should be adjusted for appropriate amounts/ratios so as to promote oxidation while prevents scavenging effects associated with excess catalyst and/or peroxymonosulfate (Section 2.1). Case law holds that “discovery of an optimum value of a result effective variable in a known process is ordinarily within the skill of the art.” See In re Boesch, 617 F.2d 272, 205 USPQ 215 (CCPA 1980). In view of this, it would have been obvious to one of ordinary skill in the art to discover workable/optimal oxidant contents within the scope of the present claims so as to produce desirable oxidation efficiency while avoiding scavenging effects associated with excess catalyst and/or peroxymonosulfate. Relevant Art The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Bottle (WO2019/000039 A1) describes degrading polyolefins with peroxides such as peroxymonosulfate (Abstract; Page 34). Tian (CN 114951237A) also describes treating plastics with iron sulfate and peroxide. Lu (Chemical Engineering Journal, 2022, 446, 137236) describes the conversion of plastic waste into liquid fules via treatment with peroxymonosulfate hydrothermal treatment. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to STEPHEN E RIETH whose telephone number is (571)272-6274. The examiner can normally be reached Monday - Friday, 8AM-4PM Mountain Standard Time. 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, Duane Smith can be reached at (571)272-1166. 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. /STEPHEN E RIETH/Primary Examiner, Art Unit 1759
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Prosecution Timeline

Jun 27, 2023
Application Filed
Jan 20, 2026
Non-Final Rejection — §103, §112 (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
44%
Grant Probability
77%
With Interview (+32.5%)
3y 3m
Median Time to Grant
Low
PTA Risk
Based on 637 resolved cases by this examiner. Grant probability derived from career allow rate.

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