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Any rejections and/or objections made in the previous Office action and not repeated below are hereby withdrawn.
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).
Claim Rejections - 35 USC § 112
Claim 18 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.
Claim 18 recites “wherein the weight ratio of diol relative to the amount of heavy impurities effluent introduced into said residue mixing zone is between 0.1 and 2.0”. The limitation at issue is already present within claim 10. Therefore, claim 18 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
Claim(s) 1-10 and 14-19 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, 5-10, and 15-19, Charra describes methods for depolymerizing PET (Abstract) comprising
a) a conditioning step implementing at least one conditioning section to produce a stream of conditioned feedstock, said conditioning section being fed at least with said polyester feedstock and being implemented at a temperature of between 225 and 275 °C (¶ 38-41). Diol effluent feed, preferably monoethylene glycol, is brought into contact with the polyester feedstock (¶ 44).
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 reaction 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 an effluent rich in liquid monomers, said diol separation step being performed in 1 to 5 successive gas-liquid separation sections each producing a gas effluent and a liquid effluent, the liquid effluent from the preceding section feeding the next section, 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), construed as “diol effluent (3)”.
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 or equal to 10 minutes (¶ 71, 78, 80).
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 (3) 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 of Charra is seen to correspond with the “zone for mixing polyester feedstock” within the claims. Charra also indicates heavy impurity effluent with oligomers can be recycled to stage a), either alone or as a mixture with a fraction of diol effluent (3), whereby the diol effluent (3) and heavy impurity/oligomer effluent are advantageously mixed together prior to transportation to stage a) (¶ 68, 78, 80), reading on a “residue mixing zone” fed with heavy impurity effluent obtained in step d) and diol effluent (3) to produce a “residue mixture”. Therefore, Charra suggests a polyester mixing zone with conditioned polyester feedstock, a diol effluent, and heavy impurity effluent, whereby the heavy impurity effluent may be a mixture of oligomer with a fraction of the diol effluent. Diol is monoethylene glycol (¶ 50), which may be fed in a superheated state (¶ 44), indicating the feed is liquid. The reactive extrusion section being fed with effluent(s) is deemed to be no different than a mixing section with a dynamic “zone for mixing the polyester feedstock” within the extruder of Charra that is fed with conditioned polyester feedstock and residue mixture comprising oligomer effluent and diol effluent from a “residue mixing zone”.
With respect to the particulars of the “residue mixing zone”, Charra teaches heavy impurity/oligomer effluent is advantageously mixed with diol effluent prior to transportation to stage a) (¶ 80). Although not describing preferred diol/heavy impurity effluent ratios, preferred temperatures within residue mixing zone, or preferred residence times within residue mixing zone, Charra teaches the quantity of diol fraction within the recycling feed is used to control viscosity/facilitate transport (¶ 78-80). Charra generally indicates the temperature selection is also important, given the temperature must be high enough so as to melt mixtures and prevent precipitation but not excessive so as to result in thermal decomposition (¶ 40, 65). It is also widely known the temperature used has a direct impact on feed viscosity. It is also known that parameters such as shear rate/length of time directly impact the extent of distributive mixing (see for instance pages 41-42 of Rauwendaal). Accordingly, the parameters of diol/heavy impurity effluent ratio, temperature, and residence time are result effective variables 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 diol/heavy impurity effluent ratios, temperatures, and residence times within the scope of the present claims so as to produce desirable feed blends and viscosities.
With respect to the particulars of the “zone for mixing polyester feedstock”, the reactive extrusion section is operated at a temperature between 225-275 degrees C (¶ 40). With respect to the quantity of diol+oligomer, Charra indicates 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. Considering the recycled oligomer feed is a fraction of the product produced from the conditioned polyester feedstock (the molar yield of BHET monomer is greater than 50%; ¶ 57), the combined diol+oligomer weight relative to fed polyester feedstock is suggested to overlap the range claimed. For instance, a ratio of < ([62 + [0.5 x 254.24]] / 192) suggests weight ratios less than 0.99. 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.
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 (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 3, Charra teaches at least 10 wt% opaque PET (¶ 33).
Regarding Claim 4, Charra teaches the feedstock contains 0.1-10 wt% pigment and 0.05-1 wt% dyes (¶ 34).
Regarding Claim 14, Charra teaches a fraction of heavy impurities effluent can be recycled to stage a) and/or b) alone or in combination with diol effluent (¶ 78, 80).
Regarding Claim 23, Charra teaches fractions of diol from stage c) can be isolated and recycled to stages a) and/or b) and/or in mixtures at stage d) (¶ 69), suggesting embodiments where a fraction of recovered diol is directed toward the zone for mixing polyester feedstock (step a) and another fraction of recovered diol is directed toward creating residue mixture at step d).
Claim(s) 20 and 21 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 ¶ 9-22 is incorporated herein by reference.
Regarding Claims 20 and 21, 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 22 is objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
Response to Arguments
Applicant's arguments filed 3/17/2026 have been fully considered but they are not persuasive.
Applicant argues using a residue mixing zone with heavy impurities effluent and additional diol effluent makes it possible to improve depolymerization efficiency and reduce stir power. This is not found persuasive. Charra already describes pre-blending heavy impurities effluent and diol effluent prior to feeding residue mixture to conditioning/mixing step a). It is not clear why applicant’s perceived benefits would not already be occurring within the express embodiments taught by Charra. Moreover, it is not necessary that the prior art suggest the combination to achieve the same advantage or result discovered by applicant. See MPEP 2144(IV).
Applicant argues Charra does not describe specifics of temperature, residence time, and mixing ratios of the residue mixing zone. This is not found persuasive as such parameters would have been obvious for reasons set forth above.
Applicant essentially argues pre-blending heavy impurities effluent and diol effluent prior to feeding residue mixture to conditioning/mixing step a) is one of many options taught by Charra. This is not found persuasive. The rejections at issue are not anticipation rejections; rather, they are obviousness rejections. Charra expressly teaches one can pre-blend heavy impurities effluent and diol effluent prior to feeding residue mixture to conditioning/mixing step a). Therefore, such an option would have been obvious in view of Charra.
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.
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/STEPHEN E RIETH/Primary Examiner, Art Unit 1759