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 .
Election/Restrictions
Applicant’s election without traverse of Group I, claims 1-8, 23 and 24 in the reply filed on 2/26/2026 is acknowledged.
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.
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 1-8, 23, and 24 are rejected under 35 U.S.C. §103 as being unpatentable over
Alidedeoglu (US 2017/0198090 A1) in view of Richard et al. (US 10,322,978 B2).Alidedeoglu
teaches:
A polyester (polybutylene terephthalate, PBT) formed from 1,4-butanediol (BDO) and terephthalic acid ([0002], [0004]).
Processing of PBT under elevated melt temperatures (about 230–280 °C) ([0025]–[0030]).
That thermal degradation and side reactions occur during processing ([0019]–[0024]).
That degradation/overhead products include BDO, tetrahydrofuran (THF), water, and methanol ([0105]).
Richard et al. teaches:
A method for producing 1,3-butadiene from 1,4-butanediol or derivatives thereof (col. 1, ll. 15–25).
A thermal decomposition / pyrolysis step converting BDO-derived feed to butadiene (col. 5, ll. 10–25).
That such conversion is carried out at temperatures of at least 400 °C (e.g., 400–700 °C) (col. 6, ll. 5–20).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to thermally decompose a polyester containing repeating units derived from 1,4-butanediol to produce butadiene by:
generating 1,4-butanediol from polyester degradation, as taught by Alidedeoglu; and
converting the resulting BDO to butadiene, as taught by Richard et al.,
because Richard et al. teaches that BDO is a suitable feedstock for butadiene production, and one of ordinary skill would have recognized that BDO generated from polyester degradation is an equivalent intermediate feedstock. Further, combining sequential reaction steps (formation of an intermediate followed by conversion to a desired product) would have been an obvious matter of process integration and efficiency optimization.
Claims 2–4 recite:
Melting prior to decomposition
Solvent-free melting
150–280 °C melting
Alidedeoglu teaches:
Heating PBT to form a melt-phase homogeneous polymer prior to further processing ([0025]–[0030]).
Melt temperatures of ~230–280 °C, which fall within the claimed range ([0025]–[0030]). The process is conducted in the melt phase without solvent.
It would have been obvious to perform the melting step under solvent-free conditions and within the claimed temperature range, since these are standard melt-processing conditions for polyesters explicitly disclosed by Alidedeoglu.
Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over references as applied to claim 1 above, and further in view of Phelps et al. (US 7,732,557 B2)
Phelps teaches:
Use of metal-containing catalysts in depolymerization:
“Suitable depolymerization catalysts include… organotitanate and organotin compounds” (col. 10, lines. 20–30)
Explicit disclosure of tin catalysts:
“the catalyst may include… a dialkyltin, a dialkyltin oxide, a dialkyltin alkoxide,
a stannoxane, and a spiro tin compound” (col. 10, lines. 30–40)
It would have been obvious to one having ordinary skill in the art before the effective filing
date of the claimed invention to carry out the thermal decomposition of the polyester using a tin
catalyst, because:
Phelps et al. teaches that polyester depolymerization reactions are performed in the presence of metal-containing catalysts, including organotin catalysts, and
such catalysts are expressly disclosed as suitable for polyester depolymerization
reactions,
thereby rendering the use of a tin catalyst an obvious selection of a known catalyst for
performing thermal decomposition of polyester.
Claim 6:
Thermal decomposition at ≥400 °C
Richard et al. teaches: Conversion of BDO-derived feed to butadiene at ≥400 °C (400–700
°C) (col. 6, ll. 5–20).
Claim 7:
Solvent-free decomposition
Both references teach:
High-temperature processing (melt and pyrolysis) inherently conducted without solvent
Claim 8 recites:
Polyester is PBAT.
Alidedeoglu teaches:
Polyesters derived from BDO (e.g., PBT) ([0002], [0004]).
It would have been obvious to select PBAT as an alternative BDO-based polyester, since
PBAT is a known member of the same class of 1,4-butanediol-based polyesters, and such
substitution represents a routine selection of a known equivalent material.
Claim 23 recites:
First thermal decomposition → produces BDO
Second thermal decomposition → produces butadiene
Combination teaches:
Alidedeoglu: polyester degradation produces BDO-containing products ([0105])
Richard et al.: BDO → butadiene via thermal decomposition (col. 5, ll. 10–25)
It would have been obvious to perform the process in two steps—first generating BDO from
polyester, then converting BDO to butadiene—because each step is individually taught and their
combination yields predictable results.
Claim 24 recites:
First step: 220–350 °C
Second step: ≥400 °C
ΔT: 100–300 °C
Alidedeoglu: ~230–280 °C melt/degradation ([0025]–[0030])
Richard et al.: ≥400 °C (col. 6, ll. 5–20)
It would have been obvious to select the claimed temperature ranges since they correspond to known operating conditions for each step, and represent result-effective variables that would have been optimized through routine experimentation (In re Aller).
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to TAM M NGUYEN whose telephone number is (571)272-1452. The examiner can normally be reached Mon - Frid.
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/TAM M NGUYEN/Primary Examiner, Art Unit 1771