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 II, claims 7-17 in the reply filed on 1/8/2026 is acknowledged.
Claims 1-6 and 18-20 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention, there being no allowable generic or linking claim. Election was made without traverse in the reply filed on 12/8/2025.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claim 14 is 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.
Claim 14 uses the terminology “a polycarbonate-based resin” and “a carbonate-based resin”. It is unclear if these two terms are meant to be one in the same or if claim 14 is requiring the presence of an additional carbonate-based resin. Accordingly, the intended scope of the claim is unclear.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claim(s) 7, 8, 10-12, 15, and 16 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Quaranta (Green Chem. 2017, 19, 5422).
Regarding Claim 7, Quaranta teaches methods of depolymerizing polycarbonates (Abstract) and describes embodiments where polycarbonate-based resin is depolymerized in solvent comprising methanol and ethanol, and carbonate precursor (dimethylcarbonate, diethylcarbonate, ethylmethylcarbonate) are separated from the product mixture (Table 8; Figure 8; Alcoholysis/work-up protocol of Page 5424-5425). The recovered materials can be used for synthesizing recycled plastic (Introduction) or alternatively the limitation “monomer composition for synthesizing recycled plastic” is only seen to constitute an intended use of the obtained materials since no apparent difference in structure is evident between the carbonate compound of Quaranta and that instantly described/claimed.
Regarding Claims 8 and 10, Quaranta teaches embodiments where the molar ratio of ethanol:methanol is 42:14 (Table 8), equivalent to 3 mol ethanol per 1 mol of methanol. Quaranta teaches 0.03 g / 0.5 g = 6 wt% (10 mol%) of DBU basic catalyst is used relative to polycarbonate (Table 8 footnote), equivalent to 0.1 mol relative to 1 mol of polycarbonate.
Regarding Claims 11 and 12, Quaranta teaches reactions take place of timespans of roughly 1-2 hr whereby dimethyl carbonate, ethylmethyl carbonate, and diethyl carbonate are produced (Table 8). Thus, over the course of Quaranta’s reaction, polycarbonate would be depolymerized in the presence of ethanol, methanol, dimethyl carbonate, ethylmethyl carbonate, and diethyl carbonate solvents. Considering 100 mol% PC conversion is reported (Table 8), there would necessarily be instances over the course of reaction where 16-20 moles of DMC, MEC, and DEC would be present relative to 1 mole of remaining polycarbonate resin.
Regarding Claims 15 and 16, Quaranta teaches working up via vacuum distilling obtained organic carbonate (Page 5425; Left Column). The residual solids after distillation are further purified (Page 5425).
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.
Claim(s) 14 is/are rejected under 35 U.S.C. 103 as being unpatentable over Quaranta (Green Chem. 2017, 19, 5422).
Quaranta teaches methods of depolymerizing polycarbonates (Abstract) and describes embodiments where polycarbonate-based resin is depolymerized in solvent comprising methanol and ethanol, and carbonate precursor (dimethylcarbonate, diethylcarbonate, ethylmethylcarbonate) are separated from the product mixture (Table 8; Figure 8; Alcoholysis/work-up protocol of Page 5424-5425). The recovered materials can be used for synthesizing recycled plastic (Introduction) or alternatively the limitation “monomer composition for synthesizing recycled plastic” is only seen to constitute an intended use of the obtained materials since no apparent difference in structure is evident between the carbonate compound of Quaranta and that instantly described/claimed.
Regarding Claim 14, Quaranta teaches polycarbonate, alcohol mixture, and catalyst are introduced in sequence to create depolymerization mixture (Page 5424). The excess quantity of alcohols of Quaranta fall within the scope of organic solvent. Quaranta therefore differs from the subject matter claimed with respect to the order of mixing ingredients. It has been held the selection of any order of mixing ingredients is prima facie obvious in the absence of new or unexpected results. MPEP 2144.04(IV)(C). In the present case, the reactions of Quaranta would proceed regardless of whether DBU catalyst is added to an alcohol/polycarbonate mixture or if DBU catalyst is first added to alcohol and then the resulting mixture added to polycarbonate. In view of such, it would have been obvious to one of ordinary skill in the art that any order of mixing ingredients, inclusive of the instantly claimed order, can be used with the expectation that Quaranta’s depolymerization reaction would predictably occur.
Claim(s) 9 is/are rejected under 35 U.S.C. 103 as being unpatentable over Quaranta (Green Chem. 2017, 19, 5422) in view of Kim (Ind. Eng. Chem. Res. 2009, 48, 6591-6599).
The discussion regarding Quaranta within ¶ 17-18 is incorporated herein by reference.
Regarding Claim 9, Quaranta differs from the subject matter claimed with respect to the molar ratio of alcohol relative to polycarbonate. However, Kim teaches it was well known in the art the ratio of alcohol to carbonate directly impacts yields of resulting monomers, whereby increases in alcohol content promote improvements in monomer yield but increases costs and energy consumption (Section 3.2; Figure 4). Accordingly, Kim indicates the relative quantity of alcohol to be a known result effective variable 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 alcohol contents within the scope of the present claims so as to produce desirable yields while minimizing costs/energy consumption.
Claim(s) 7, 9-14, and 16 is/are rejected under 35 U.S.C. 103 as being unpatentable over Gorman (WO 2020/257234 A1).
Regarding Claims 7 and 11, Gorman teaches methods of depolymerizing polycarbonates (Abstract) and describes embodiments where polycarbonate-based resin is depolymerized in solvent comprising methanol, toluene, and carbonate precursor (dimethylcarbonate) is separated from the product mixture (¶ 49-52). The recovered materials can be used for synthesizing recycled plastic (¶ 47) or alternatively the limitation “monomer composition for synthesizing recycled plastic” is only seen to constitute an intended use of the obtained materials since no apparent difference in structure is evident between the carbonate compound of Gorman and that instantly described/claimed.
Although the particular embodiments of Gorman’s examples do not use a methanol/ethanol mixture, Gorman teaches the alcohol used can be any C1-C6 alcohol, such as methanol, ethanol, or a combination thereof (¶ 17). Accordingly, it would have been obvious to one of ordinary skill in the art to substitute methanol with a methanol/ethanol mixture, and thereby predictably afford workable depolymerizable mixtures in accordance with the teachings of Gorman.
Regarding Claim 9, Gorman teaches embodiments where 500 g of solvent containing 250 g of alcohol (methanol) is used relative to 100 g bisphenol A polycarbonate (¶ 49), equivalent to a molar ratio of 7.8 : 0.3 = 26:1 based on molecular weights of 32 g/mol and 290.3 g/mol for methanol and polycarbonate respectively. Thus, the embodiment of Gorman differs with respect to the relative molar ratio of alcohol to polycarbonate. In this regard, Gorman teaches the ratio of alcohol to cosolvent used varies widely between 0.1:1 to 1:0.1 (¶ 19), equivalent to 9-91 wt% of alcohol within the solvent used. Thus, it is evident Gorman is suggestive of overlapping molar quantities of alcohol solvent relative to polycarbonate. 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 Gorman suggests the claimed range. A person of ordinary skill would be motivated to use the claimed amount, based on the teachings of Gorman. See MPEP 2123.
Regarding Claim 10, Gorman teaches the use of 4 g x 0.4 = 1.6 g of sodium hydroxide base is used relative to 100 g of polycarbonate (¶ 49), equivalent to a molar ratio of 0.04 : 0.3 = 0.13 : 1 based on molecular weights of 40 g/mol and 290.3 g/mol for sodium hydroxide and polycarbonate respectively.
Regarding Claim 12, Gorman teaches embodiments where 500 g of solvent containing 250 g of cosolvent (toluene) is used relative to 100 g bisphenol A polycarbonate (¶ 49), equivalent to a molar ratio of 2.7 : 0.3 = 9.0:1 based on molecular weights of 92.1 g/mol and 290.3 g/mol for methanol and polycarbonate respectively. Thus, the embodiment of Gorman differs with respect to the relative molar ratio of cosolvent to polycarbonate. In this regard, Gorman teaches the ratio of alcohol to cosolvent used varies widely between 0.1:1 to 1:0.1 (¶ 19), equivalent to 9-91 wt% of alcohol within the solvent used. Thus, it is evident Gorman is suggestive of overlapping molar quantities of cosolvent relative to polycarbonate. 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 Gorman suggests the claimed range. A person of ordinary skill would be motivated to use the claimed amount, based on the teachings of Gorman. See MPEP 2123.
Regarding Claim 13, Gorman teaches embodiments where 500 g of solvent containing 250 g of cosolvent (toluene) and 250 g of methanol (¶ 49), equivalent to a molar ratio of 2.7 : 7.8 = 0.3:1 based on molecular weights of 92.1 g/mol and 32 g/mol for toluene and methanol respectively. Thus, the embodiment of Gorman differs with respect to the relative molar ratio of solvents. In this regard, Gorman teaches the ratio of alcohol to cosolvent used varies widely between 0.1:1 to 1:0.1 (¶ 19), equivalent to 9-91 wt% of toluene within the solvent used. Thus, it is evident Gorman is suggestive of overlapping molar quantities. 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 Gorman suggests the claimed range. A person of ordinary skill would be motivated to use the claimed amount, based on the teachings of Gorman. See MPEP 2123.
Regarding Claim 14, Gorman teaches polycarbonate, alcohol, cosolvent, and basic catalyst are introduced to create depolymerization mixture (¶ 49). Gorman therefore differs from the subject matter claimed with respect to the order of mixing ingredients. It has been held the selection of any order of mixing ingredients is prima facie obvious in the absence of new or unexpected results. MPEP 2144.04(IV)(C). In the present case, the reactions of Gorman would proceed regardless of whether NaOH catalyst is added to an alcohol/polycarbonate mixture or if NaOH catalyst is first added to alcohol and then the resulting mixture added to polycarbonate. In view of such, it would have been obvious to one of ordinary skill in the art that any order of mixing ingredients, inclusive of the instantly claimed order, can be used with the expectation that Gorman’s depolymerization reaction would predictably occur.
Regarding Claim 16, Gorman teaches purifying the depolymerization reaction mixture after separation of dialkyl carbonate compound (¶ 50-52).
Claim(s) 8 and 15 is/are rejected under 35 U.S.C. 103 as being unpatentable over Gorman (WO 2020/257234 A1) in view of Quaranta (Green Chem. 2017, 19, 5422).
The discussion regarding Gorman and Quaranta within ¶ 23-30 is incorporated herein by reference.
Regarding Claim 8, Gorman differs from the subject matter claimed in that a preferred ratio between ethanol and methanol is not described. Quaranta teaches it was known mixed dialkyl carbonates are of synthetic importance as potential precusors of unsymmetrical ethers, which can be synthesized directly by using ethanol/methanol mixtures (Page 5423; Left Column). Quaranta teaches the relative quantities of methanol and ethanol directly impact the relative yields of DMC, DEC, and EMC mixed carbonate (Figure 8; Table 8). Accordingly, Quaranta indicates the relative quantity of methanol and ethanol to be a known result effective variable 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 methanol/ethanol ratios within the scope of the present claims so as to produce desirable yields of DMC, DEC, and/or EMC.
Regarding Claim 15, Gorman teaches separating dialkyl carbonate via distillation from the depolymerization reaction mixture (¶ 50). Gorman differs from the subject matter claimed in that vacuum distillation is not described. In this regard, Quaranta teaches it was known vacuum distillation can be used to isolate dialkyl carbonates from the resulting depolymerization mixtures (Page 5425; Left Column). In view of the prior art’s indication that ambient pressure and vacuum distillation are both suitable methods in isolating dialkyl carbonates from depolymerization mixtures, it would have been obvious to one of ordinary skill in the art to substitute ambient pressure distillation with vacuum distillation, thereby predictably affording workable methods of isolating dialkyl carbonate products.
Claim(s) 17 is/are rejected under 35 U.S.C. 103 as being unpatentable over Gorman (WO 2020/257234 A1) in view of Ogasawara (JP2004-277396A). As the cited JP publication is in a non-English language, a machine-translated version of the publication will be cited to.
The discussion regarding Gorman and Quaranta within ¶ 23-30 is incorporated herein by reference.
Regarding Claim 17, Gorman differs from the subject matter claimed in that neutralization prior to distillation is not described. Ogasawara is also directed toward methods of obtaining dialkyl carbonates from polycarbonates using alkali base and alcohol (Abstract; Examples). Ogasawara teaches after depolymerization, the mixture is preferably neutralized with acid, thereby avoiding colored impurities and descreased yields due to dialkyl carbonate hydrolysis (¶ 26). It would have been obvious to one of ordinary skill in the art to neutralize the depolymerization mixtures of Gorman with acid prior to distillation because doing so would avoid colored impurities and descreased yields due to dialkyl carbonate hydrolysis as taught by Ogasawara.
Claim(s) 7, 8, and 10-17 is/are rejected under 35 U.S.C. 103 as being unpatentable over Ogasawara (JP2004-277396A) in view of Quaranta (Green Chem. 2017, 19, 5422). As the cited JP publication is in a non-English language, a machine-translated version of the publication will be cited to.
Regarding Claim 7, Ogasawara teaches methods of depolymerizing polycarbonates (Abstract) and describes embodiments where polycarbonate-based resin is depolymerized in alcohol solvent and carbonate precursor (dimethylcarbonate) are separated from the product mixture (¶ 38-42). The recovered materials can be used for synthesizing recycled plastic (¶ 1) or alternatively the limitation “monomer composition for synthesizing recycled plastic” is only seen to constitute an intended use of the obtained materials since no apparent difference in structure is evident between the carbonate compound of Ogasawara and that instantly described/claimed.
Ogasawara teaches the alcohol used can be various materials, inclusive of methanol and ethanol (¶ 18). Ogasawara differs from the siubject matter claimed in that a mixture of methanol and ethanol is not described. Quaranta is also directed toward methods of depolymerizing polycarbonates with alcohols (Abstract). Quaranta teaches it was known mixed dialkyl carbonates are of synthetic importance as potential precusors of unsymmetrical ethers, which can be synthesized directly by using ethanol/methanol mixtures (Page 5423; Left Column). Accordingly, it would have been obvious to one of ordinary skill in the art to utilize methanol/ethanol mixtures within the protocols of Ogasawara because doing so would facilitate the creation of precursors toward unsymmetrical ethers as taught by Quaranta.
Regarding Claim 8 although Ogasawara does not describe preferred ratios of methanol/ethanol, Quaranta teaches the relative quantities of methanol and ethanol directly impact the relative yields of DMC, DEC, and EMC mixed carbonate (Figure 8; Table 8). Accordingly, Quaranta indicates the relative quantity of methanol and ethanol to be a known result effective variable 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 methanol/ethanol ratios within the scope of the present claims so as to produce desirable yields of DMC, DEC, and/or EMC.
Regarding Claim 10, Ogasawara teaches embodiments where 10 mol% of NaOH base is reated relative to ester bond of aromatic polycarbonate (¶ 38), corresponding to 0.2 mol of base relative to 1 mol of polycarbonate (since one mol of carbonate linkage corresponds to 2 mol of ester bond).
Regarding Claim 11, Ogasawara teaches the further inclusion of methylene chloride solvent (¶ 38).
Regarding Claim 12, Ogasawara teaches organic solvent is included in amounts spanning 40-1,000 pbw relative to 100 pbw polycarbonate (¶ 16), which for methylene chloride is equivalent to 0.5-11.8 mol methylene chloride per 0.3 mol polycarbonate, based on molecular weights of 84.9 g/mol and 290.3 g/mol for methylene chloride and polycarbonate respectively. Such a range is roughly equivalent to 1.7-39 mol methylene chloride per mole of polycarbonate, which overlaps the range 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 Ogasawara suggests the claimed range. A person of ordinary skill would be motivated to use the claimed amount, based on the teachings of Ogasawara. See MPEP 2123.
Regarding Claim 13, Ogasawara teaches embodiments where 200 pbw methylene chloride is used relative to 48 pbw of alcoholic solvent (methanol) (¶ , equivalent to 1.6:1 molar ratio based on molecular weights of 84.9 g/mol and 32 g/mol for methylene chloride and methanol respectively.
Regarding Claim 14, Ogasawara teaches embodiments where base is added to alcoholic solvent and then organic solvent/polycarbonate is added (¶ 38). Ogasawara therefore differs from the subject matter claimed with respect to the order of mixing ingredients. It has been held the selection of any order of mixing ingredients is prima facie obvious in the absence of new or unexpected results. MPEP 2144.04(IV)(C). In the present case, the reactions of Ogasawara would proceed regardless of whether NaOH is premixed with methanol alone or if NaOH is first added to alcohol/organic solvent and then the resulting mixture added to polycarbonate. In view of such, it would have been obvious to one of ordinary skill in the art that any order of mixing ingredients, inclusive of the instantly claimed order, can be used with the expectation that Ogasawara’s depolymerization reaction would predictably occur.
Regarding Claims 15-17, Ogasawara teaches neutralizing with acid when depolymerization is complete, subsequently separating dialkyl carbonate from depolymerization mixture via vacuum distillation, and then purifying the resulting residue (¶ 38-42).
Claim(s) 9 is/are rejected under 35 U.S.C. 103 as being unpatentable over Ogasawara (JP2004-277396A) in view of Quaranta (Green Chem. 2017, 19, 5422), Sumuilov (Polymer Science, Series B, 2020, 62(4), 411-415), and Hu (Polymer, 1998, 39(16), 3841-3845). As the cited JP publication is in a non-English language, a machine-translated version of the publication will be cited to.
The discussion regarding Ogasawara and Quaranta within ¶ 39-47 is incorporated herein by reference.
Regarding Claim 9, Ogasawara teaches preferably 1.2-3.5 mol alcohol per mol of ester bond of polycarbonate is used from the standpoint of recovery rate of bisphenol compound and depolymerization amount (¶ 19), equivalent to 2.4-7 mol per mol carbonate unit. Therefore, Ogasawara differs form the subject matter claimed in that the preferred quantities are outside the range claimed. In this regard, the ideal amount of alcoholic solvent required is known to be dependent on the presence/identity/quantity of what organic solvent is used so as to achieve optimal depolymerization rate and yield (see Table 1 of Sumuilov, Tables 1 and 2 of Hu, and Figure 4 of Quaranta). Thus, the prior art establishes that the content of alcohol solvent is a known result effective variable 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 methanol contents for a given system with particular identities/amounts of organic solvent within the scope of the present claims so as to produce desirable polymerization rates and yields.
Conclusion
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/STEPHEN E RIETH/Primary Examiner, Art Unit 1759