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Any rejections and/or objections made in the previous Office action and not repeated below are hereby withdrawn.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 § 103
Claim(s) 7, 10-13, 15, and 16 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).
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 and toluene whereby 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.
Gorman teaches polycarbonate, alcohol, cosolvent, and basic NaOH catalyst are introduced to create depolymerization mixture (¶ 49). Gorman teaches the alcohol used can be a combination of methanol and ethanol (¶ 17). With respect to the quantity of alcohol relative to polycarbonate, 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, Gorman differs from the subject matter claimed with respect to 1) the amount of alcohol relative to polycarbonate, 2) the order of base addition, and 3) the relative proportion of methanol and ethanol.
With respect to alcohol quantity, 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.
With respect to addition order, 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.
With respect to methanol/ethanol ratio, 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 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 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.
Regarding Claim 16, Gorman teaches purifying the depolymerization reaction mixture after separation of dialkyl carbonate compound (¶ 50-52).
Claim(s) 17 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) and 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 ¶ 6-15 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, 10-13, and 15-17 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), 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.
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 embodiments where NaOH 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.
Ogasawara differs from the subject 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. 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.
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.
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 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).
Response to Arguments
Applicant's arguments filed 5/4/2026 have been fully considered but they are not persuasive.
The rejections pertaining to Quaranta as a primary reference are withdrawn in view of Applicant’s amendment.
With respect to Gorman/Ogasawara, Applicant argues the references fail to describe the content of methanol+ethanol relative to polycarbonate. This is not found persuasive. Gorman expressly teaches a combination of methanol+ethanol can be used and is suggestive of overlapping alcohol quantities. With respect to the Ogasawara the limitation at issue is met via combination of references. The prior art sets forth that it was known the ideal amount of alcoholic solvent required is 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). Both references explicitly describe the use of sodium hydroxide base.
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
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