Prosecution Insights
Last updated: April 19, 2026
Application No. 17/493,162

Composition of Styrenic Polymers Derived Through Depolymerization of Polystyrene

Final Rejection §103§112
Filed
Oct 04, 2021
Examiner
BLAND, ALICIA
Art Unit
1759
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Greenmantra Recycling Technologies Ltd.
OA Round
3 (Final)
50%
Grant Probability
Moderate
4-5
OA Rounds
3y 2m
To Grant
62%
With Interview

Examiner Intelligence

Grants 50% of resolved cases
50%
Career Allow Rate
347 granted / 700 resolved
-15.4% vs TC avg
Moderate +12% lift
Without
With
+11.9%
Interview Lift
resolved cases with interview
Typical timeline
3y 2m
Avg Prosecution
40 currently pending
Career history
740
Total Applications
across all art units

Statute-Specific Performance

§101
0.7%
-39.3% vs TC avg
§103
45.2%
+5.2% vs TC avg
§102
18.9%
-21.1% vs TC avg
§112
21.7%
-18.3% vs TC avg
Black line = Tech Center average estimate • Based on career data from 700 resolved cases

Office Action

§103 §112
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 . Priority The claims have an effective date of the filing of the provisional application 4/4/19 Information Disclosure Statement The information disclosure statement (IDS) submitted on 9/17/25, 6/26/25, 4/24/25 have been considered by the examiner. The reference lined through in the IDS dated 6/26/25 did not have an English translation Response to Arguments Applicant argues polystyrene derived from a catalytic depolymerization of a polystyrene feedstock is distinct from that of native polystyrene having the same MW. Applicant argues increased conjugation is found and the olefin content of claims 6 and 16 distinguishes such, Applicant argues the backbone or terminal olefins would be more compatible with various organic and aqueous solvent formulations, Applicant argues the color of the polystyrene would be different. Applicant argues mere purification would not ‘fix’ the above differences, e.g. if you purified it the differences would still be there. Applicant argues the MW and Tg both correspond to polymers having lower MWs. The Examiner disagrees. Burden is on Applicant to show a distinct product is produced. Applicant has not given any quantitative data that one cannot purify polystyrene and get the same color as native polystyrene. Applicant has not shown any of these to give a distinct (unexpected) difference. The burden for product by process limitations is to show a distinct (unexpected) product is produced because a slightly different product is prima facie obvious. The olefin content of claims 6 and 16 are met by Yeager, thus these arguments are not found persuasive. Given that the olefin content is embraced, the argued endgroups and solubility is also seemingly embraced. Further, the Tg of 280k polystyrene is 100C [0092-Yeager] and one would not expect much difference for a Tg when the MW was within the claimed range. As such Applicant’s arguments are not found persuasive and the rejection stands as set forth below. Claim Warning The claim warning over claim 5 is withdrawn, the claim has been cancelled. Claim Rejections - 35 USC § 112 The following is a quotation of the first paragraph of 35 U.S.C. 112(a): (a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention. The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112: The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention. Claim 21 is rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention. “catalyst is a zeolite” is deemed new matter. The specification [0040] supports wherein the catalyst may comprise a zeolite supported system but the zeolite itself is not a zeolite. The catalyst is another compound supported on said zeolite. Claim Rejections - 35 USC § 103 The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action. Claim(s) 1-4, 6-20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Yeager (US 2003/0215588). Elements of this rejection are as previously set forth, reiterated below in its entirety in italics. Regarding claim 16, the polymerization of polystyrene in Yeager would implicitly have catalyst residue therein, since purity won’t reach 100% even if it is purified. There are no concentrations and/or species of catalyst. Thus, Yeager meets this new requirement Yeager discloses the use of a polystyrene polymer in a curable resin (abstract). The polystyrene polymer may have a MW range from about 10,000-400,000 amu [0092]. This embraces and thusly renders obvious the MW of claim 1. See In re Wertheim. The limitation “derived from a catalytic depolymerization of a polystyrene feedstock” is a product by process limitation. The process of making the styrenic polymer is not pertinent unless Applicant shows a distinct product is produced. Herein, there could be any number of purification steps after a depolymerization reaction, wherein the end product may solely be polystyrene, just like the native/virgin polystyrene of Yeager. The polystyrenes (alone) of [0091] meet claim 1. Claims 2-5 are drawn to the process of making and, as above, these are not pertinent unless a distinct (unexpected) product is shown (and properly claimed). The polystyrene may have up to 10 wt% butadiene [0092], as required by claim 6. Zinc stearate may be used in the overall final composition in an amount of 1 wt% [0155]. The order of mixing is prima facie obvious See also In re Burhans, 154 F.2d 690, 69 USPQ 330 (CCPA 1946) (selection of any order of performing process steps is prima facie obvious in the absence of new or unexpected results); In re Gibson, 39 F.2d 975, 5 USPQ 230 (CCPA 1930) (Selection of any order of mixing ingredients is prima facie obvious.), thus mixing the zinc stearate first with the polystyrene is prima facie obvious and meets claim 7. Titanium dioxide is added in amounts of 15 wt% (table 11) and iron oxide is another filler disclosed in [0108], its use in amounts about the same as titanium dioxide or any other filler (e.g. 15 wt%) is prima facie obvious. Additionally iron fiber fillers may be used in amounts of 5-80 wt% [0113]. Again, the order of mixing is prima facie obvious so mixing any of the above with polystyrene before making the final composition is prima facie obvious. Elements above meet claims 7-10. The MW of Yeager meets that of claim 11, also the styrene polymer discussed above embraces that of the claims/specification. Thus, the Tg of claim 11 is found to be embraced by the reference. if there is any difference between the above composition and the composition of the instant claims the difference would have been minor and obvious. "Products of identical chemical composition can not have mutually exclusive properties." A chemical composition and its properties are inseparable. Therefore, if the prior art teaches the identical chemical structure, the properties applicant discloses and/or claims are necessarily present. See MPEP 2112.01(I) , In re Best, 562 F2d at 1255, 195 USPQ at 433, Titanium Metals Corp v Banner, 778 F2d 775, 227 USPQ 773 (Fed Cir 1985), In re Ludtke, 441 F2d 660, 169 USPQ 563 (CCPA 1971) and Northam Warren Corp v D F Newfield Co, 7 F Supp 773, 22 USPQ 313 (EDNY 1934). Elements above meet claim 11. The styrene polymer may be a maleic anhydride-styrene copolymer (abstract), some of which would implicitly have maleic anhydride endgroups, meeting the grafted acid requirements of claim 12. Since the composition requirements are met, the solubility requirements of claim 13 must be embraced. Since any amount of purification can be done to a depolymerized polymer, claims 14-15 are met by the product by process discussion above. Elements above further meet claims 16-20 wherein no non-polystyrene materials are claimed in the final product, thus, the 100% polystyrene discussed above meets claim 19. Claim(s) 16, 20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Yeager in view of Leclerc (US 20060135713). Yeager includes elements as set forth above. Yeager discloses using polystyrene but does not disclose how it was made. Leclerc discloses ligands, compositions and complexes used to polymerize styrene to polystyrene (abstract). These ligands, complexes and catalysts may be supported on zeolite supports [0241], amongst other supports. Supports such as zeolites are thusly suitably known as catalyst supports in the polymerization of polystyrene. It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to include in Yeager the use of zeolite supported catalysts/ligands/complexes, as taught by Leclerc, since this is a suitably known way to produce polystyrene in the art. It is the Examiner’s position that even if the polystyrene is purified after (which is not disclosed in Yeager-but could happen), purity of 100% would not be reached and some catalyst and zeolite support would be therein. If not purified certainly some catalyst and zeolite support would be present in the final product. Conclusion Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a). A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action. Any inquiry concerning this communication or earlier communications from the examiner should be directed to ALICIA BLAND whose telephone number is (571)272-2451. The examiner can normally be reached Mon - Fri 9:00 am -3:00 pm 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, Curt Mayes can be reached on 571-272-1234. 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. /ALICIA BLAND/ Primary Examiner, Art Unit 1759
Read full office action

Prosecution Timeline

Oct 04, 2021
Application Filed
Jul 13, 2024
Non-Final Rejection — §103, §112
Jan 21, 2025
Response Filed
Mar 24, 2025
Non-Final Rejection — §103, §112
Sep 28, 2025
Response Filed
Oct 06, 2025
Final Rejection — §103, §112
Apr 08, 2026
Request for Continued Examination
Apr 09, 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

4-5
Expected OA Rounds
50%
Grant Probability
62%
With Interview (+11.9%)
3y 2m
Median Time to Grant
High
PTA Risk
Based on 700 resolved cases by this examiner. Grant probability derived from career allow rate.

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