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 .
Claim Rejections - 35 USC § 112
Claims 2-15 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. The terms “preferably,” “preferentially,” and preference are repeatedly recited throughout claims 2-15.
A broad range or limitation together with a narrow range or limitation that falls within the broad range or limitation (in the same claim) may be considered indefinite if the resulting claim does not clearly set forth the metes and bounds of the patent protection desired. See MPEP § 2173.05(c). In the present instance, claim 2 recites the broad recitation 0.05 and 5.00, and the claim also recites 0.5 and 3.00 which is the narrower statement of the range/limitation. The same corrections are required for claims 3-15. The claim(s) are considered indefinite because there is a question or doubt as to whether the feature introduced by such narrower language is (a) merely exemplary of the remainder of the claim, and therefore not required, or (b) a required feature of the claims.
Regarding claim 3, line 3, the phrase "such as" renders the claim indefinite because it is unclear whether the limitations following the phrase are part of the claimed invention. See MPEP § 2173.05(d).
Claim Rejections - 35 USC § 103
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.
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.
Claims 1-20 are rejected under 35 U.S.C. 103 as being unpatentable over Charra et al (US 2019/0161595 A1) in view of Tamada (JP 2004196880 A) and further in view of Fang et al (US 2021/0024718 A1).
Applicants’ claimed invention is directed to a process for depolymerization of a polyester feedstock, comprising: a) a conditioning step using a means for at least partially melting the polyester feedstock and at least one static or dynamic mixer, located downstream of the means for at least partially melting the polyester feedstock, to produce a conditioned feedstock stream, conditioning step a) being operated at a temperature of between 200 and 300°C and fed at least with the polyester feedstock and an alcohol stream comprising an alcohol compound, with a ratio by weight of the alcohol stream in relation to the polyester feedstock of between 0.03 and 6.00, the means for at least partially melting the polyester feedstock being at least fed with the polyester feedstock, each static or dynamic mixer being fed with at least a fraction of the alcohol stream and with a polyester stream, with a volume degree of dilution with alcohol compound of between 3% and 70%, the volume degree of dilution with alcohol compound being the ratio between the volume flow rate of the alcohol stream fraction which feeds the static or dynamic mixer under consideration and the sum of the volume flow rates of the alcohol stream fraction and of the polyester stream which feed the static or dynamic mixer under consideration, the polyester stream which feeds a static or dynamic mixer comprising the polyester feedstock and all of the fractions of the alcohol stream that are introduced in step a) upstream of the static or dynamic mixer under consideration; b) a step of depolymerization, which is fed at least with the conditioned feedstock stream obtained from step a), and is operated at a temperature of between 150 and 300°C, with a residence time of between 0.1 and 10 h and with a ratio by weight between the total amount of alcohol compound present in step b) and the amount of diester contained in the conditioned feedstock stream of between 0.3 and 8.0.
Charra teaches a method for depolymerizing a polyester feedstock comprising PET, said method comprising:
a step of conditioning supplied with said polyester feedstock;
a step of depolymerization by glycolysis supplied at least with the effluent from step a) and with a make-up diol, carried out at a temperature of between 200°C and 400°C, with 1 to 20 mol of diol per mole of diester in said polyester feedstock and a polyester residence time of between 0.1 and 5 hours, converting the PET into BHET monomers and BHET oligomers;
a step of separating the diol supplied at least with the effluent of step b), carried out at a temperature of between 100 and 250°C, at a pressure lower than that of step b) and producing a diol effluent and a liquid monomer-rich effluent, said step of separating the diol being carried out in 1 to 5 successive gas-liquid separation sections, the liquid effluent from the previous section supplying the subsequent section, all of the gas effluents being condensed to form the diol effluent, the liquid effluent from the final gas-liquid separation section constituting the liquid monomer-rich effluent;
a step of separating the liquid monomer-rich effluent from step c) into a heavy impurity effluent and a pre-purified monomer effluent, carried out at a temperature below 250°C and a pressure below 0.001 MPa with a liquid residence time of less than 10 minutes, and
(e) a step of decolorization of the pre-purified monomer effluent, carried out 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 monomer effluent. See claim 1.
Charra also discloses that the conditioning step is preferably carried out by extrusion at a temperature of between 225 and 275°C, said mixing section being at least supplied with said polyester feedstock and a diol effluent, with a residence time of less than 15 minutes. See paragraphs [0037]-[0042].
Charra does not disclose that the conditioning step employs at least one static or dynamic mixer located downstream of the extruder.
However, Tamada teaches a method for depolymerizing polyethylene terephthalate comprising the heating, melting and depolymerization of the polyethylene terephthalate to be recycled, and wherein the polyethylene terephthalate is melted in an extruder, a glycol is added at the outlet of the extruder, and the mixture of polyethylene terephthalate and glycol is mixed in a mixer, then the mixture is introduced into a reactor for the depolymerization step. In the example of Tamada, the PET is melted in an extruder (the melting point of PET is approximately 260°C), the weight ratio of the alcohol stream to the PET feedstock is 0.49, the level of dilution by volume of alcohol compound entering the mixer is 39%, and the temperature in the mixer is 210°C. See abstract; figure 1; claims 1 and 2.
Tamada does not mention the temperature in the extruder or the residence time of the conditioned feedstock in the reactor.
The subject matter of claims 1-6, 12 and 15-20 differs from the disclosure of Tamada in that the temperature during the extrusion of the polyester is between 200 and 300°C (or between 250 and 290°C; cf. claim 6) and in that the residence time of the conditioned feedstock is from 0.1 to 10 hours; the volume dilution with alcohol; the ratio of alcohol stream to polyester feedstock; temperature of extruder and the number of static or dynamic mixers.
However, Tamada discloses that the PET is melted in the extruder, implying a temperature of at least 260°C (melting point of PET). In addition, the temperature in the extruder is generally kept as low as possible to minimize thermal degradation of the polyester. The optimum temperature for the extrusion step could be determined through routine experimentation with reasonable expectation of success.
It would have been obvious to one of ordinary skill in the art, prior to the effective filing date of the claimed invention to combine the teachings of Tamada, Charra and Fang’s processes to determine the optimal residence time in the reactor after the step of mixing the polyester with the alcohol could be obtained through routine experimentation with a reasonable expectation of success. The subject matter of claims 1-6, 12 and 15-20 are predictable implementation of routine parameters tuning using established methods taught across Charra, Tamada, and Fang et al.
The subject matter of claim 7 also differs from the disclosure of Tamada in that the extruder is also supplied with a fraction of the alcohol stream.
According to the application, this can help to liquefy at least part of the polyester feedstock and can therefore contribute to reducing the viscosity of the stream at the outlet of said means, thereby contributing to the overall homogenization of the at least partially molten polyester feedstock and of the alcohol compound. The objective technical problem to be solved can therefore be considered that of providing a method that makes it possible to reduce the viscosity of the polyester feedstock and to improve the homogenization of the polyester-alcohol mixture during the conditioning step.
Fang discloses (claim l; drawings) a method for depolymerization by alcoholysis in which part of the alcohol is mixed with the polyester in the extruder. Fang teaches (paragraph [0005]) that this makes it possible to solve the problem of the long depolymerization time and of the large dosage of alcoholysis agent caused by the heterogeneous solid-liquid reaction during the alcoholysis.
A person skilled in the art, prior to the effective filing date of the claimed invention would combine the teaching of Fang with the disclosure of Tamada in order to solve the objective technical problem and would thereby arrive at the subject matter of claim 7 without exercising inventive skill. Consequently, the subject matter of claim 7 cannot be considered to be patentable over the cited art.
Regarding claims 8-12, the optimization of extruder temperature, residence time, polyester to alcohol ratio, mixing element count and dilution degree in claim 8-12 is obvious under 35 USC 103 because it represents the predictable implementation of routine parameter tuning using established methods taught across Charra, Tamada, and Fang et al.
The subject matter of claim 13 differs from the disclosure of Tamada in that the method comprises a separation step to produce an alcohol-based effluent and a diester monomer effluent, as defined in claim 13. According to the application, the main role of this step is to recover all or part of the unreacted alcohol compound, which can
subsequently advantageously be recycled to steps a) and/or b) and can also make it possible to recover all or part of the diol generated during the depolymerization.
Charra and Fang (paragraph [0039]) describe such a separation method after the depolymerization step. A person skilled in the art would carry out a separation step as described in claim 13 after the conditioning step and the depolymerization step in Tamada, without exercising inventive skill.
Regarding claim 14, Charra also discloses ([0081]) that the alcohol recovered during the separation step is reused to supply the conditioning step. A person skilled in the art would use the alcohol from the separation step to supply the conditioning step, without exercising inventive skill. The subject matter of claim 14 therefore is obvious in view of Charra.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JAFAR F PARSA whose telephone number is (571)272-0643. The examiner can normally be reached M-F 10:00 AM-6:30PM.
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/JAFAR F PARSA/Primary Examiner, Art Unit 1692
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