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 7-16 in the reply filed on 1/14/2026 is acknowledged.
Claims 1-6 and 17-20 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention, there being no allowable generic or linking claim.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 1/14/2026.
Information Disclosure Statement
Foreign Ref Cite #3 has been lined through in the IDS received 3/31/2025 because a copy of the AU reference has not been submitted. 37 CFR 1.98(a) requires a legible copy of each foreign patent document. In the interest of compact prosecution, the submitted WO2019/140245 A1 document has been considered and is cited in the attached PTO-892.
Claim Objections
Claim 12 is objected to because of the following informalities: It is believed claim 12 should recite “cooling a solution in which the depolymerization reaction product is dissolved”. Appropriate correction is required.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(d):
(d) REFERENCE IN DEPENDENT FORMS.—Subject to subsection (e), a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers.
The following is a quotation of pre-AIA 35 U.S.C. 112, fourth paragraph:
Subject to the following paragraph [i.e., the fifth paragraph of pre-AIA 35 U.S.C. 112], a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers.
Claim 16 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 16 requires purifying the depolymerization reaction product after removing the diol component. However, the required recrystallization step of claim 7 is a purification step taking place after removing the diol component. Accordingly, claim 16 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
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) 7, 8, and 10-16 is/are rejected under 35 U.S.C. 103 as being unpatentable over England (U.S. Pat. No. 3,544,622) in view of Lee (U.S. Pat. No. 6,013,835) and Essaddam (US 2017/0008826 A1).
Regarding Claims 7, 8, 10, 14, and 16, England teaches methods for preparing monomers from polyethylene terephthalate comprising subjecting PET to depolymerization in the presence of ethylene glycol, removing ethylene glycol component, and recovering terephthalic acid monomer (Abstract; Examples). England differs from the subject matter claimed in that further purification of crude terephthalic acid via recrystallization is not performed.
Essaddam teaches it was known in the art depolymerization of waste PET to terephthalic acid results in various impurities such as 4-formylbenzoic acid and 4-methylbenzoic acid (¶ 4-17). Lee teaches it was known recrystallization can be used to purify terephthalic acid to remove impurities such as toluic acid and carboxybenzaldehyde (Abstract; Col. 2, Lines 12-59; Tables 1-8). It would have been obvious to one of ordinary skill in the art to apply the recrystallization procedure of Lee toward the crude terephthalic acid of England because doing so would provide terephthalic acid of high purity as taught by Lee.
Lee teaches embodiments where crude terephthalic acid is dissolved in crystallization solvent such as NMP or DMAC at high temperature and cooled to recrystallize out terephthalic acid (Col. 14, Line 42 to Col. 15, Line 28). Lee teaches embodiments where the obtained crystallized terephthalic acid is passed through a wash column and counter-current water is added to remove crystallization solvent, after which the crystals are soaked in water at temperatures of about 150-250 degrees C and then filtered (Col. 10, Lines 35-39; Col. 15, Lines 30-40). The disclosed temperature range 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 Lee suggests the claimed range. A person of ordinary skill would be motivated to use the claimed amount, based on the teachings of Lee. See MPEP 2123.
Regarding Claim 11, Lee teaches embodiments where recrystallization occurs with 31.8 g TA and 248.4 g of solvent (Table 1), equivalent to 7.8 pbw solvent per 1 pbw TA.
Regarding Claim 12, Lee teaches embodiments where dissolution/saturation temperatures occur within the claimed range, such as 60 degrees C or 110 degrees C (Tables 1 and 2). Lee teaches suitable crystallization temperatures range widely from about 5 to about 50 degrees (Claim 3), 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 Lee suggests the claimed ranges. A person of ordinary skill would be motivated to use the claimed amount, based on the teachings of Lee. See MPEP 2123.
Regarding Claims 13 and 15, England teaches depolymerizing PET with sodium hydroxide base in the presence of ethylene glycol solvent, whereby after filtering to remove diol component the resulting disodium terephthalate is neutralized with an acid prior to washing (Example 2). A stoichiometric amount of hydroxide relative to terephthaloyl content in PET is used (Col. 5, Lines 49-52), equivalent to roughly 2 moles of base relative to 1 mole of PET.
Claim(s) 9 is/are rejected under 35 U.S.C. 103 as being unpatentable over England (U.S. Pat. No. 3,544,622) in view of Lee (U.S. Pat. No. 6,013,835), Essaddam (US 2017/0008826 A1), and Lee-2 (U.S. Pat. No. 5,840,968).
The discussion regarding England, Lee, and Essaddam within ¶ 14-19 is incorporated herein by reference.
Regarding Claim 9, to the extent Lee does not describe a preferred quantity of water, Lee-2 teaches the solubility of TPA in water increases substantially at high temperatures (Figure 5):
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530
816
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. Thus, the quantity of hot water used with respect to TPA is a known result effective variable, since clearly the more water used at higher temperatures, the more TPA dissolution would occur. 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 optimal or workable water quantities within the scope of the present claims so as to produce desirable degrees of crystallization solvent removal from TPA while avoiding excessive TPA crystal dissolution.
Claim(s) 7, 8, and 10-16 is/are rejected under 35 U.S.C. 103 as being unpatentable over England (U.S. Pat. No. 3,544,622) in view of Ham (U.S. Pat. No. 2,949,483) and Lee (U.S. Pat. No. 6,013,835).
Regarding Claims 7, 8, 10, 14, and 16, England teaches methods for preparing monomers from polyethylene terephthalate comprising subjecting PET to depolymerization in the presence of ethylene glycol, removing ethylene glycol component, and recovering terephthalic acid monomer (Abstract; Examples). England differs from the subject matter claimed in that further purification of crude terephthalic acid via recrystallization is not performed.
Ham teaches terephthalic acid is capable of being purified via recrystallization in organic solvents such as N-methylpyrrolidone achieves terephthalic in a highly pure state with removal of impurities such as toluic acid (Col. 1, lines 33-55; Col. 2, Lines 13-25). It would have been obvious to one of ordinary skill in the art to recrystallize the crude terephthalic acids of England using the protocols of Ham because doing so would result in highly pure materials as taught by Ham.
Ham teaches dissolving terephthalic acid in hot NMP, after which a NMP-diacid salt is crystallized out at lower temperatures. After which, the salt crystals are filtered, washed with hot boiling water to further purify the salt, regenerate terephthalic acid, and remove NMP (Col. 3, Line 63 to Col. 4, Line 8; Examples). Ham therefore differs from the subject matter claimed in that NMP-diacid crystals are not washed with water at 200-300 degrees C. Lee also pertains to recrystallization of terephthalic acid with solvents such as NMP (Abstract; Col. 14, Line 42 to Col. 15, Line 28). Lee teaches the obtained crystallized terephthalic acid is passed through a wash column and counter-current water is added to remove crystallization solvent, after which the crystals are soaked in water at temperatures of about 150-250 degrees C and then filtered (Col. 10, Lines 35-39; Col. 15, Lines 30-40). Lee teaches the soaking protocol is advantageous as it eliminates any possible residual NMP solvent trapped in the crystals before the product is subjected to the final filtration/drying (Col. 4, Lines 46-55; Col. 10, Lines 35-38). It would have been obvious to one of ordinary skill in the art to soak the crystals of Ham with water at a temperature of 150-250 degrees C, because doing so would eliminate any possible residual NMP solvent trapped in the crystals before the product is subjected to the final filtration/drying as taught by Lee.
The disclosed temperature range 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 Lee suggests the claimed range. A person of ordinary skill would be motivated to use the claimed amount, based on the teachings of Lee. See MPEP 2123.
Regarding Claim 11, Ham teaches embodiments where 8 pbw of solvent is used relative to 1 pbw crude terephthalic acid (Example 1).
Regarding Claim 12, Ham teaches dissolving crude terephthalic acid in NMP at temperatures spanning 50-130 degrees C after which the mixture is cooled to 10-45 degrees C (Col. 3, Lines 70-74). The dissolution temperature is consistent with the range claimed and the cooling temperature 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 Ham suggests the claimed range. A person of ordinary skill would be motivated to use the claimed amount, based on the teachings of Ham. See MPEP 2123.
Regarding Claims 13 and 15, England teaches depolymerizing PET with sodium hydroxide base in the presence of ethylene glycol solvent, whereby after filtering to remove diol component the resulting disodium terephthalate is neutralized with an acid prior to washing (Example 2). A stoichiometric amount of hydroxide relative to terephthaloyl content in PET is used (Col. 5, Lines 49-52), equivalent to roughly 2 moles of base relative to 1 mole of PET.
Claim(s) 9 is/are rejected under 35 U.S.C. 103 as being unpatentable over England (U.S. Pat. No. 3,544,622) in view of Ham (U.S. Pat. No. 2,949,483), Lee (U.S. Pat. No. 6,013,835), and Lee-2 (U.S. Pat. No. 5,840,968).
The discussion regarding England, Ham, and Lee, within ¶ 24-30 is incorporated herein by reference.
Regarding Claim 9, to the extent Ham/Lee does not describe a preferred quantity of water, Lee-2 teaches the solubility of TPA in water increases substantially at high temperatures (Figure 5):
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media_image1.png
530
816
media_image1.png
Greyscale
. Thus, the quantity of hot water used with respect to TPA is a known result effective variable, since clearly the more water used at higher temperatures, the more TPA dissolution would occur. 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 optimal or workable water quantities within the scope of the present claims so as to produce desirable degrees of crystallization solvent removal from TPA while avoiding excessive TPA crystal dissolution.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to STEPHEN E RIETH whose telephone number is (571)272-6274. The examiner can normally be reached Monday - Friday, 8AM-4PM Mountain Standard Time.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Curtis Mayes can be reached at (571)272-1234. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/STEPHEN E RIETH/Primary Examiner, Art Unit 1759
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