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 .
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 10 December 2025 has been entered.
Claim Amendments
Applicant’s amendments to claims 61 and 64 and new claims 81 and 82 filed on 10 December 2025 have been received and considered for this action.
Claim Objections
Claim 81 is objected to because it appears to be missing words:
Claim 61 recites “(b) introducing at least a portion of said liquefied waste plastic into an upflow pyrolysis film reactor…” Claim 81 purports to further limit claim 61 but recites only “wherein (b) introducing the at least portion of said liquified waste into an extruder.”
The specification references an extruder as a heated vessel that serves as part of the liquification system in [0226], as well as a “screw extruder” being an alternative to a film reactor in [0313]. However, because claim 81 depends upon claim 61 where the pyrolysis reactor is an upflow film pyrolysis reactor, claim 81 will be interpreted as requiring an extruder to be used as part of the liquification system, consistent with [0226].
Appropriate correction of claim 81 to clarify the role of the extruder in a manner consistent with the specification as originally filed is required. One possible claim amendment is as follows:
“Claim 81: The process according to claim 61, wherein (b) introducing the at least a portion of said liquefied waste plastic into an upflow pyrolysis reactor further comprises having the liquefied waste plastic in an extruder.”
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 61-66 are rejected under 35 U.S.C. 103 as being unpatentable over Yin et al. (Chem. Eng. J. 2014, 237, 229–235) in view of Winter et al. (US 5,904,879 A) and Jin et al. (Chin. J. Chem. Eng. 2018, 26, 400-406).
Regarding claim 61, Yin discloses a chemical recycling process comprising:
(a) providing a liquefied waste plastic (the use of molten waste plastic, see below, means it was provided);
(b) introducing at least a portion of said liquefied waste plastic into an upflow pyrolysis film reactor comprising a plurality of stationary film-generating structures (vertical falling film reactor for waste plastics’ pyrolysis consists of vertical tubes in parallel with round or rectangular outer frame. The molten plastic falls down along the inside of tube surfaces, and the hot gas flows outside the tubes. There is no movable parts inside the reactor; p. 230, column 2, ¶ 2); and,
(c) flowing at least a portion of said liquefied waste plastic upwardly along said stationary film-generating structures (Fig. 6 shows positive (upward) velocity for at least a portion of the liquified waste plastic; Section 4.2) to thereby pyrolyze said liquefied waste plastic and form a pyrolysis effluent comprising a pyrolysis gas (heat transfers from the heating tube surface to the molten PP by heat conduction and convection, and then the molten PP is pyrolyzed to volatile (pyrolysis gas and oil); Section 4.1).
Yin also teaches that the pyrolysis of waste plastics is considered one of the most feasible large-scale methods of energy regeneration, since waste plastic is a valuable source of liquid and gas fuels, as well as chemicals (p. 229, column 1, ¶ 1) and their method is therefore a chemical recycling method.
Yin does not teach the use of a liquification agent comprising an alcohol, a glycol, a motor oil, water or any combination thereof. Nor does Yin teach operating the pyrolysis film reactor at a temperature of from about 600 °C to 1100 °C.
However, Winter teaches a related process for recycling waste plastic to valuable products (col. 1, lines 13-15) and further teaches that motor oil can be used as a liquefication agent (melting medium; col. 6, lines 13-15).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to use motor oil as a liquefication agent in the method of Yin, as taught by Winter. One of ordinary skill in the art would have been motivated to do so because Winter teaches that such an oil helps to melt the waste plastic, which is the same operation that Yin is trying to accomplish, and because Yin teaches that molten plastic is hard to flow and difficult to heat up (p. 229, col. 2, line 2), two problems that adding a melting medium/liquefication agent would help to solve.
Regarding the temperature, Yin teaches operating the pyrolysis reactor at temperatures as high as 500 °C (773 K; Section 4.1), but not in the range of 600 °C to 1100 °C. However, Jin teaches the implementation of a falling film upflow pyrolysis reactor like that studied by Yin, including studying the effect of differing reaction temperatures (vertical falling film pyrolysis reactor was constructed, and the pyrolysis process of molten PP in the reactor was experimentally investigated. The influence of the heating temperature on the yields and compositions of the oil and non-condensable gas were studied; p. 401, col. 1, ¶ 3). In particular, Jin teaches operating the reactor at 600 °C and at 625 °C (Fig. 2-4), each of which lie in the instantly claimed range, and further teaches that at higher temperature the conversion degree increases (Fig. 2) and the composition of the product mixture changes to include more aromatics (yield of aromatics increases with temperature increasing, from 0.4 wt% at 550 °C to 10.2 wt% at 625 °C; p. 403, ¶ 1 and Fig. 4).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to operate the reactor in the method of modified Yin at a temperature of 600 °C or 625 °C, as taught by Jin. One of ordinary skill in the art would have been motivated to do so in order to increase conversion degree and to generate a greater aromatic fraction of the product, as taught by Jin.
Regarding claim 62, modified Yin teaches the process of claim 61 where the stationary film-generating structures comprise tubes (vertical tubes in parallel; p. 230, column 2, ¶ 2).
Regarding claim 63, modified Yin teaches the method of claim 62, but does not teach the liquified waste plastic having a residence time in said upflow pyrolysis film reactor of 2 to 300 seconds.
However, Jin teaches the implementation of a falling film upflow pyrolysis reactor for molten plastic and also that residence time (RT) is a variable for controlling yields of oil and non-condensable gas (p. 403, column 2, ¶ 1).
As the yield of oil and non-condensable gas can be modified by adjusting the residence time, the precise residence time would have been considered a result effective variable by one having ordinary skill in the art before the effective filing date of the invention. As such, without showing unexpected results, the claimed residences times cannot be considered critical. Accordingly, one of ordinary skill in the art before the effective filing date of the invention would have optimized, by routine experimentation, the residence times in the method of Yin to obtain the desired balance between reaction time and product yield, as taught by Jin.
Therefore, since it has been held that where the general conditions of the claim are disclosed in the prior art, discovering the optimum or workable ranges involves only routine skill in the art, the claimed residence times are seen as obvious in view of Jin and Yin. “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” See In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). The discovery of an optimum value of a known result effective variable, without producing any new or unexpected results, is within the ambit of a person of ordinary skill in the art. See In re Boesch, 205 USPQ 215 (CCPA 1980). See MPEP § 2144.05(II).
Regarding claim 64, modified Yin teaches the process of claim 63, where Jin teaches operating the upflow pyrolysis reactor operating at temperatures up to 625 °C. Jin does not explicitly teach operating the reactor at any temperatures in the range of 650 °C to 800 °C.
However, Jin does teach that temperature is a result-effective variable for increasing the conversion degree (Fig. 2), the fraction of aromatic compounds in the product mixture (Fig. 4), and the ratio of LPO to HPO (Fig. 6). As such, without showing unexpected results, the claimed temperatures cannot be considered critical.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to vary the reaction temperature by routine experimentation in order to obtain the desired balance of conversion degree and/or the fraction of aromatic compounds to the LPO/HPO ratio in the product mixture, as taught by Jin.
Generally, differences in temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such temperature is critical. "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). The discovery of an optimum value of a known result effective variable, without producing any new or unexpected results, is within the ambit of a person of ordinary skill in the art. See In re Boesch, 205 USPQ 215 (CCPA 1980). See MPEP 2144.05.
Regarding claim 65, modified Yin teaches the method of claim 61, where Winter teaches liquefying at least one solid waste plastic in a melt tank to form said liquified waste plastic (bulk waste plastic materials are fed to a melting vessel where the waste plastic material comes into direct contact with hot oil melting medium … to melt the waste plastic to form a molten viscous mixture; col. 4, lines 35-40).
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to use a melt tank, as taught by Winter, in the method of Yin. One of ordinary skill would have been motivated to do so because such a vessel provides a reactor in which to mix the melting medium/liquefication agent and the waste plastic.
Regarding claim 66, modified Yin teaches the method of claim 65 where the motor oil melting medium can be considered a dissolution solvent, as these materials are expected to form a homogenous mixture.
Claims 67, 68, and 71 are rejected under 35 U.S.C. 103 as being unpatentable over Yin et al. (Chem. Eng. J. 2014, 237, 229–235) in view of Winter et al. (US 5,904,879 A) and Jin et al. (Chin. J. Chem. Eng. 2018, 26, 400-406), as applied to claims 61, 65, and 66 above, and further in view of Miller (US 2003/0199718 A1; hereinafter “Miller ‘718”).
Regarding claim 67 and 68, modified Yin teaches the method of claim 66, and Winter further teaches that the dissolution solvent can be a cracked oil recovered from the plastic processing (hot cracked oil is recycled to the melting vessel; col. 5, lines 12-13). However, neither Winter nor Yin teaches the dissolution solvent being a pyrolysis oil in particular.
However, Miller ‘718 also teaches the pyrolysis of waste plastics where the waste plastics are first liquefied in a separate unit (a heating unit which functions to melt the plastics feed…the molten feed is then forwarded to the pyrolysis unit; [0025]-[0026]). Miller ‘718 further teaches that the liquefying can occur in the presence of a dissolution solvent (the solids may be dissolved or dispersed in a suitable solvent and the liquid fed to the heater; [0023]), that the solvent can be a pyrolysis oil derived from the pyrolysis effluent (a diesel cut from a fractionator in the process; [0026]; effluent from unit 50 is processed in fractionator 35 to recover diesel; [0033])), and that the inclusion of such a solvent can help lower the viscosity of the liquid and bring in heat to help melt the plastic ([0026]).
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention to have the liquefying in the method of modified Yin occur in the presence of a dissolution solvent, wherein the dissolution solvent comprises a pyrolysis oil derived from the pyrolysis effluent, as taught by Miller ‘718. One of ordinary skill in the art would have been motivated to do so in order to decrease the viscosity of the melt and to help bring in heat to melt the plastic, as taught by Miller ‘718.
Regarding claim 71, modified Yin teaches the method of claim 61, and teaches the viscosity of the model system polypropylene being 0.1 poise (0.01 kg m-1 s-1) above 250 °C (Section 4, ¶ 2). However, Yin does not teach the viscosity of true liquefied waste plastic.
However, Miller ‘718 teaches that the viscosity of a liquefied waste plastic stream can be adjusted by introduction of a solvent, and that lowering the viscosity makes the liquefied waste plastic easier to pump (the feed may be combined with a lower viscosity liquid… to lower viscosity and make the feed easier to pump; [0026]).
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to optimize by routine experimentation the viscosity of the liquefied waste plastic stream in the method of Yin to arrive in the instantly claimed range of less than 3,000 poise at 350 °C and 10 radians/s. One of ordinary skill in the art would have been motivated to do so because Miller ‘718 teaches that reduced viscosity makes the material easier to pump, and therefore represents the use of a known technique to improve a similar process.
It is noted that the courts have held that “where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). See MPEP 2144.05 II. Therefore, the claimed ranges of viscosity merely represent an obvious variant and/or routine optimization of the teaching to use lower viscosity feeds in the cited prior art.
Claims 69-70 are rejected under 35 U.S.C. 103 as being unpatentable over Yin et al. (Chem. Eng. J. 2014, 237, 229–235) ) in view of Winter et al. (US 5,904,879 A) and Jin et al. (Chin. J. Chem. Eng. 2018, 26, 400-406), as applied to claims 61 and 65 above, and further in view of Miller et al. (US 6,150,577; hereinafter “ Miller ‘577”).
Regarding claim 69, modified Yin teaches the method of claim 65, where Yin studies the pyrolysis of polypropylene as model system for a waste plastic stream (it is necessary to discuss the influence of heating temperature on the pyrolysis products of waste plastics in a new pyrolysis reactor…and the pyrolysis process of molten PP in the reactor was experimentally investigated; Jin, p. 401, column 1, ¶ 2-3, and PP is used as typical plastics to set up the model; Yin, p. 230, column 2, ¶ 3). Yin is otherwise silent on the waste plastic stream composition and therefore does not teach the solid waste plastic comprising at least 90 weight percent of one or more polyolefins.
However, Miller ‘577 also teaches a recycling process for waste plastic by pyrolysis of a waste plastic stream (column 2, lines 35-42) and that the feed preferably contains about 95 wt% to about 100 wt% polyethylene (column 3, line 64).
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to use in the method of modified Yin a solid waste plastic feed comprising 95 wt% to 100 wt% polyethylene, as taught by Miller ‘577, thereby meeting the claim limitation of the solid waste plastic stream comprising at least 90 weight percent polyolefin. One of ordinary skill in the art would have been motivated to do so because Miller teaches that these compositions are preferable for a plastic pyrolysis process.
Regarding claim 70, modified Yin teaches the method of claim 65, but is silent with respect to the weight percent of PET or PVC in the solid waste plastic feed.
However, Miller ‘577 teaches that is preferable to keep the chlorine content of the feed less than 20 ppm (column 4, line 8). Because PVC is (C2H3Cl)n, it contains a chlorine weight percent of 56.7%. The maximum PVC content in a feed that is less than 20 ppm Cl is therefore 36 ppm, or 0.0036%.
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to use in the method of modified Yin a solid waste plastic feed comprising not more that 0.0036% PVC, as taught by Miller ‘577, which meets the limitation of not more than 3 weight percent of PVC recited in the instant claim. One of ordinary skill in the art would have been motivated to do so because Miller teaches that these compositions are preferable for a plastic pyrolysis process.
Claim 72 is rejected under 35 U.S.C. 103 as being unpatentable over Yin et al. (Chem. Eng. J. 2014, 237, 229–235) in view of Winter et al. (US 5,904,879 A) and Jin et al. (Chin. J. Chem. Eng. 2018, 26, 400-406), as applied to claim 61, and further in view of Butler et al. (Waste Biomass Valor. 2011, 2, 227-255) and Miller et al. (US 6,150,577; hereinafter “ Miller ‘577”).
Regarding claim 72, modified Yin teaches the method of claim 61 but Yin is silent with respect to the halogen content of the liquefied waste plastic.
However, Butler teaches that in waste plastic pyrolysis processes halogens are undesirable (undesirable elements e.g. halogens (e.g. Chlorine); p. 230, column 1, ¶ 1). Butler does not put a limit on the halogen content of the waste plastic feedstock or the liquefied waste plastic that enters the pyrolysis process.
Miller ‘577 also teaches a recycling process for waste plastic by pyrolysis of a waste plastic stream (column 2, lines 35-42) and that the feed may contain chlorine, but at preferably less than 20 ppm (column 4, line 8). This is interpreted as being a ppm based on weight.
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to use in the method of Yin a liquefied waste plastic where the halogen content is less than 20 ppmw. One of ordinary skill in the art would have been motivated to do so because they would recognize the similar chemical properties of the halogens and that if there was a desire to keep chlorine below 20 ppmw because of its detrimental effects on the pyrolysis process and/or products, as taught by Miller ‘577 and Butler, there would also be desire to the keep all halogens below this level.
Claim 81 is rejected under 35 U.S.C. 103 as being unpatentable over Yin et al. (Chem. Eng. J. 2014, 237, 229–235) in view of Winter et al. (US 5,904,879 A) and Jin et al. (Chin. J. Chem. Eng. 2018, 26, 400-406), as applied to claim 61 above, and further in view of McNamara et al. (US 2012/0261247 A1).
Regarding claim 81, modified Yin teaches the process of claim 61, but does not teach the use of an extruder as part of the liquefication system (See Claim Objections).
However, McNamara also teaches a process for the pyrolysis of waste plastics (abstract) and further teaches the use of an extruder to melt the plastic prior to feeding into the pyrolysis reactor ([0066]).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to use an extruder to melt the plastic in the method of modified Yin. One of ordinary skill in the art would have been motivated to do so because while Yin is silent on the melting apparatus, McNamara teaches that an extruder is appropriate to melt a plastic feed and supply it to a pyrolysis reactor.
Claim 82 is rejected under 35 U.S.C. 103 as being unpatentable over Yin et al. (Chem. Eng. J. 2014, 237, 229–235) in view of Winter et al. (US 5,904,879 A), Jin et al. (Chin. J. Chem. Eng. 2018, 26, 400-406), and McNamara et al. (US 2012/0261247 A1), as applied to claim 81 above, and further in view of Ullom (US 2016/0024390 A1) and as evidenced by Ritter (“What's that stuff? Motor Oil”, Chemical & Engineering News, 13 March 2006. Retrieved from <URL: https://cen.acs.org/articles/84/i11/Motor-Oil.html>).
Regarding claim 82, modified Yin teaches the process of claim 81, but does not teach contacting the liquefied waste plastic with a plasticizer in the extruder.
However, Ullom also teaches a process for pyrolysis of hydrocarbon materials ([0016]) including waste plastics ([0034]), as well as the use of an extruder to prepare the materials for feeding into the pyrolysis reactor (thermal kiln reactor; [0034] and Fig. 1). Ullom further teaches that in the extruder, the materials can be contacted with petroleum-based liquids (varying proportions of petroleum-based liquids, if any as may be desired, can be injected into port 206 in extruder 201 ; [0034]) and that doing so is especially effective at reducing the viscosity of the melt (modest amounts of petroleum-based oil often results in material decrease in melt viscosity, especially if injected at injection port 206); [0052]).
As analyzed above for claim 61, Winter teaches that motor oil, a petroleum-based liquid, can be used as a liquefication agent (melting medium; col. 6, lines 13-15). Additionally, motor oil can be considered a plasticizer, as it is comprised of largely paraffinic oils, as evidenced by Ritter (¶ 4), which are example plasticizers recited in the instant specification ([0226]).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to contact the liquefied waste plastic of Yin with a plasticizer (motor oil) in the extruder, as taught by Ullom. One of ordinary skill in the art would have been motivated to do so because Ullom teaches that incorporation of such additives in an extruder is successful at reducing viscosity, with high viscosity being a problem recognized by Yin (molten plastic … is usually characterized with high viscosity … made it hard to flow; Section 1).
Response to Arguments
Applicant’s arguments with respect to the rejections of claims 61-62 and 65-66 over Yin in view of Winter, pages 6-7 of the reply filed 10 December 2025, have been fully considered and are persuasive. Neither Yin nor Winter teach the temperature recited in the amended claim. The prior rejections of these claims have been withdrawn. However, upon further consideration, a new grounds of rejection is made over Yin in view of Winter and Jin.
Applicant's arguments, pages 7-9, with respect to Jin teaching away from the instantly claimed temperature ranges have been fully considered but they are not persuasive.
Applicant argues that because Jin shows that higher temperature conditions produce greater amounts of LPO and lower amounts of HPO, that one of ordinary skill would have no motivation to raise the temperature above those temperatures recited by Yin. However, even though Applicant may prioritize a high HPO fraction over all else, others in the art may be differently motivated. For example, Jin also teaches that higher temperatures yield a greater fraction of aromatics, which would be one motivation to operate the reactor at temperatures in the instantly claimed range.
Applicant argues for the allowability of the dependent claims based upon the assertion that Yin in view of Winter and Jin does not teach the features of claim 61. Those arguments not being persuasive, the features of the dependent claims were examined based upon their further limitations and likewise rejected, as analyzed above.
Conclusion
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/NICHOLAS A. PIRO/Assistant Examiner, Art Unit 1738
/PAUL A WARTALOWICZ/Primary Examiner, Art Unit 1735