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 .
Response to Amendment
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Any rejections and/or objections made in the previous Office action and not repeated below are hereby withdrawn.
No new grounds of rejection are presented within this office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a).
Claim Rejections - 35 USC § 103
Claim(s) 1-5, 7, 8, 11-16, and 20-22 is/are rejected under 35 U.S.C. 103 as being unpatentable over Charra (WO 2018/007356 A1) in view of Rauwendaal (Encyclopedia of Polymer Science and Technology). As the cited WO document is in a non-English language, the English equivalent, US 2019/0161595 A1 has been utilized in place of the WO document. All citations are made with respect to the above-mentioned US document.
Regarding Claims 1, 8, 10, 21, and 22, Charra teaches processes for depolymerizing PET feedstock (Abstract) comprising:
a) a conditioning step implementing with an extruder (construed as having at least one conditioning section) to produce a stream of conditioned feedstock, wherein the extruder is fed at least with said polyester feedstock and is implemented at a temperature of between 225 and 275 °C (¶ 38-41). Diol effluent feed is brought into contact with the polyester feedstock (¶ 44). Diol effluent is mixed in quantities of less than 1.0 mol of diol (MW 62 g/mol) relative to mol of PET diester (MW 192 g/mol) (¶ 44), corresponding to a diol/polyester wt/wt feed ratio of roughly less than 0.32. The less than 0.32 range overlaps the 0.1 to 1.0 range claimed. The diol effluent is preferably monoethylene glycol (¶ 50), implying diol effluents with ethylene glycol in excess of 95 wt%.
b) a step of depolymerization by glycolysis, fed at least with the mixed stream and optionally with a diol supply so that the total amount of diol feeding said step b) is adjusted to 1 to 20 mol of diol per mole of diester feeding said step b), performed at a temperature of between 200 and 400 °C, and a residence time of between 0.1 and 5 hours (¶ 47).
c) a step of separating out the diol fed at least with the effluent from step b), performed at a temperature of between 100 and 250 °C, at a pressure below that of step b) and producing a diol effluent and a liquid effluent rich in monomers, wherein said diol separation step is performed in 1 to 5 successive gas-liquid separation sections that produce gas effluent and the effluent rich in liquid monomers, the liquid effluent obtained from the last gas-liquid separation section constituting the effluent rich in liquid monomers, the gas effluents all being recovered to constitute the diol effluent (¶ 60-63).
d) a step of separating the effluent rich in liquid monomers obtained from step c) into a heavy impurities effluent and a pre-purified monomers effluent, performed at a temperature of less than 250 °C and a pressure of less than 0.001 MPa with a liquid residence time of less than 10 minutes (¶ 71), wherein at least a fraction of heavy impurities effluent can be recycled directly into reaction section of b) (¶ 78), and
e) a step of decolorizing the pre-purified monomers effluent, performed at a temperature of between 100 and 250 °C, and at a pressure of between 0.1 and 1.0 MPa in the presence of an adsorbent and producing a purified monomers effluent (¶ 83).
With respect to mixing section of step a), Charra teaches conditioning state a) can be performed within an extruder whereby polyester feedstock is fed into an extruder into a screw conveying section and then diol effluent is fed into a latter portion of the screw conveying section (termed reactive extrusion section) prior to feeding the mixed feed into depolymerization stage (¶ 41, 44). The reactive extrusion section is deemed to be no different than a dynamic mixer section within the extruder of Charra. The reactive extrusion section is operated at a temperature between 225-275 degrees C (¶ 40).
Charra indicates the residence time within the entire screw conveying section is less than 15 minutes (¶ 42). Although Charra does not indicate what proportion corresponds to the reactive extrusion section, it is known in the art that parameters such as shear rate/length of time directly impacts the extent of distributive mixing within extruders (see for instance pages 41-42 of Rauwendaal). Thus, the residence time within the mixing section is a known result effective variable subject to routine optimization by one of ordinary skill in 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 residence times within the scope of the present claims so as to effect sufficient melt mixing within Charra’s mixtures.
Regarding Claims 2 and 13, Charra teaches at least 10 wt% opaque PET, preferably at least 15 wt% (¶ 33).
Regarding Claims 3, 4, and 14, Charra teaches the feedstock contains 0.1-10 wt% pigment, preferably 0.1-5 wt%, and 0.05-1 wt% dyes (¶ 34), which suggests colored PET.
Regarding Claims 5, 7, 15, and 16, Charra teaches the extruder is fed at least with said polyester feedstock and is implemented at a temperature of between 225 and 275 °C (¶ 38-41). The reactive extrusion section is operated at a temperature between 225-275 degrees C (¶ 40). The disclosed ranges overlap those claimed. 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 Charra suggests the claimed range. A person of ordinary skill would be motivated to use the claimed amount, based on the teachings of Charra. See MPEP 2123.
Regarding Claims 11, Charra teaches embodiments where glycol feed is superheated (¶ 44).
Regarding Claim 12, Charra teaches the introduced glycol feed can be fraction of diol effluent obtained from step c) (¶ 68-69).
Regarding Claim 20, Charra teaches in step a) diol effluent is mixed in quantities of less than 1.0 mol of diol (MW 62 g/mol) relative to mol of PET diester (MW 192 g/mol) (¶ 44), corresponding to a diol/polyester wt/wt feed ratio of roughly less than 0.32. Thus, the range of Charra is just outside the instantly claimed 0.35-1.0 range. However, a prima facie case of obviousness exists where the claimed ranges or amounts do not overlap with the prior art but are close to the extent the same properties or characteristics would be expected. MPEP 2144.05(I). In this regard, Charra teaches the less than 1.0 mol range is merely “advantageously” (¶ 44), which implies values falling slightly outside are nonpreferred embodiments within the scope of invention. Accordingly, it would have been obvious to one of ordinary skill in the art to utilize diol/PET feedstock ratios toward the lower limit of the instantly claimed 0.35-1.0 range, thereby predictably affording workable depolymerization/purification processes in accordance with the teachings of Charra.
Claim(s) 17 and 18 is/are rejected under 35 U.S.C. 103 as being unpatentable over Charra (WO 2018/007356 A1) in view of Rauwendaal (Encyclopedia of Polymer Science and Technology) and Dickey (Kirk-Othmer Encyclopedia of Chemical Techology). As the cited WO document is in a non-English language, the English equivalent, US 2019/0161595 A1 has been utilized in place of the WO document. All citations are made with respect to the above-mentioned US document.
The discussion regarding Charra and Rauwendaal within ¶ 6-19 is incorporated herein by reference.
Regarding Claims 17 and 18, Charra teaches depolymerization occurs via mechanical stirring (¶ 51). Charra differs from the subject matter claimed in that a stirring power within the depolymerization reactors is not described. Dickey teaches it was known in the art stirring intensity and stirring power per volume are known result effective variables subject to routine optimization by one of ordinary skill in the art for effective mixing for chemical reactions (Sections 2.1, 3.1, and 4.2). 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 or optimal power per volumes of mixing within the scope of the present claims so as to produce desired end results.
Allowable Subject Matter
Claim 19 is allowed.
Response to Arguments
Applicant's arguments filed 2/25/2026 have been fully considered but they are not persuasive.
Applicant argues the various teachings of Charra constitute different embodiments. Applicant argues Charra describes various outputs for heavy impurities effluent, only one of which is to depolymerization step b). This is not found persuasive. The rejections of record are not anticipation rejections; they are obviousness rejections. Charra’s comprehensive disclosure meets the limitations at issue and thus, such would have been obvious to one of ordinary skill in the art in view of the reference.
Applicant argues the specific combination recited in the claims result in reduced viscosity streams feeding the reaction section. This is not found persuasive. The examples of the specification probe a conditioning section with PET feedstock alone vs a combination of PET feedstock and diol. Charra unambiguously describes feeding the conditioning section with diol. It is unclear how or why the benefits applicant ascribes to such a process are not already occurring with the disclosure of Charra. Charra even states the diol effluent reduces/controls the viscosity of the heavy impurity effluent (i.e. unconverted PET polymer) in some embodiments (¶ 80), thus the concept of modifying the viscosity characteristics of a PET polymer blend using diol is unsurprising.
Conclusion
THIS ACTION IS MADE FINAL. 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.
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/STEPHEN E RIETH/Primary Examiner, Art Unit 1759