DETAILED ACTION
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claims 1-9 and 13-20 are pending as amended on 3/13/2026. Claims 1-6 and 16-20 stand withdrawn from consideration.
The rejections set forth below have been modified to reflect the incorporation of limitations previously recited in claim 11 into independent claim 7. The changes to the rejection were necessitated by Applicant’s amendment, and therefore, this action is properly made final.
Any rejections and/or objections made in the previous Office action and not repeated below are hereby withdrawn. The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office Action.
Specification
The disclosure is objected to because of the following informalities: Table 1 on p 39 contains a “recrystallization condition” column. In Table 1, the amount of water in the recrystallization condition for Example 2 is erroneously written as “100 times relative to PET mass…” The amount of water for Example 2 should actually be “10 times relative to PET mass,” consistent with the description of Example 2 on p 35, lines 24-26. Note that Table 2 (on p 42) contains the correct amount of water (10 times) for Example 2. Appropriate correction is required.
Claim Rejections - 35 USC § 103
Claim(s) 7-9 and 13-15 is/are rejected under 35 U.S.C. 103 as being unpatentable over England (US 3544622) in view of Taylor et al (US 3574727), Standard Oil Company (GB 1152575) and Zubrick (The Organic Chem Lab Survival Manual; 1988, John Wiley and Sons, pp 91-110).
As to claims 7, 8, 14 and 15, England discloses a method for the recovery of disodium salt of terephthalic acid and terephthalic acid itself from scrap PET (Col 1, lines 29-37). England discloses alkaline saponification of PET in the presence of water and ethylene glycol (solvents which are recited in instant claim 14) using sodium hydroxide (col 1, lines 44-56, which corresponds to the presently recited “subjecting” step of depolymerizing a polymer synthesized from terephthalic acid, i.e., PET), and then separating the disodium terephthalate which precipitates from the mother liquor by filtration (col 1, line 71 to col 2, line 2; which corresponds to the presently recited step of removing a diol component, because the diol component remains in the mother liquor; see col 3, lines 72-75).
England discloses converting the disodium terephthalate to terephthalic acid by dissolving in water (col 4, lines 35-37) and neutralizing with a strong acid such as hydrochloric acid (col 4, lines 49-53), and then washing with successive portions of water to remove occluded soluble salts (col 4, lines 56-59), which corresponds to the step of neutralizing the depolymerization reaction product from which diol has been removed with an acid, as recited in claim 15, and which meets the “washing” step recited in claim 7, wherein the solvent for the washing is water, as recited in claim 8. The neutralization in England’s process occurs before the washing step with successive portions of water (meeting the requirement in claim 15 of neutralizing before the washing step). England does not disclose heating or cooling the water used for the step of washing the filter cake of terephthalic acid, and therefore, one having ordinary skill in the art would have at least envisaged the use of room temperature water (i.e., 20~25 C, which falls within the range of 20 C or more to 100 C or less recited in claim 7) for carrying out England’s disclosed step of washing to remove occluded salts.
England does not disclose purifying the obtained terephthalic acid by recrystallization, and therefore, fails to teach the presently recited steps of dissolving the washed terephthalic acid and cooling the solution to recrystallize terephthalic acid.
One having ordinary skill in synthetic chemistry would have recognized that recrystallization is a common purification technique: a desired (impure) substance is dissolved in a solvent, and the solution is then cooled to a temperature at which the desired substance precipitates from the solution in the form of crystals. The crystals of desired substance can then be separated from the solvent and from impurities, which remain dissolved in the solvent, such as by filtration and washing of the desired crystals. If evidence is needed that this basic knowledge is known to one of ordinary skill in the art, see Zubrick’s Chapter on Recrystallization starting on p 91, particularly, the discussion at the top of p 92 (points 1-3) and the bottom of p 97.
Taylor discloses a process for purifying crude terephthalic acid (col 1, lines 21-22). Taylor discloses that a further reduction in impurities in recovered terephthalic acid can be realized by recrystallizing from water. Taylor discloses heating to a temperature between 240-280 C with sufficient pressure to maintain the water in a liquid state. The terephthalic acid is dissolved in the heated solution, and then subsequently cooled to room temperature so as to precipitate additionally purified terephthalic acid, which may be recovered by filtration (col 3, lines 61-73).
Standard Oil also discloses the purification of aromatic polycarboxylic acids (p 1, lines 11-16), and teaches that because terephthalic acid has low solubility in water, either large volumes of water or high temperatures are required in order for the desired terephthalic acid quantity to be put into solution (p 2, line 126 to p 3, line 4). Standard Oil provides a table showing the amounts of terephthalic acid which can be dissolved in 100 g of water at temperatures ranging from 365-522 F (i.e., 185-272 C).
Considering the level of ordinary skill in the art and the disclosures of Taylor and Standard Oil as set forth above, one would have known generally suitable conditions for the recrystallization of terephthalic acid using water as a solvent in order to remove impurities from terephthalic acid. When carrying out the recrystallization of terephthalic acid in water, the person having ordinary skill in the art would have been motivated to select an appropriate temperature for heating terephthalic acid in water (such as within a range of 185-272 C as in Standard Oil, or 240-280 C, as in Taylor) in order to dissolve the terephthalic acid in a given volume of water. The person having ordinary skill in the art would have been subsequently motivated to slowly cool the solution to any appropriate temperature at which terephthalic acid is no longer soluble in water (and at which the undesired impurities remain soluble in water) in order to precipitate/crystallize the terephthalic acid while keeping impurities dissolved in the solvent. It would have been obvious to the person having ordinary skill in the art, therefore, to have increased the degree of purity of England’s recovered terephthalic acid by dissolving the terephthalic acid in water at any appropriate temperature within Standard Oil’s range of 185-272 C (including a temperature which falls within the presently claimed range of 200-220 C), and by then slowly cooling the aqueous solution to any appropriate temperature at which terephthalic is insoluble in water (including a temperature which is 50 to 200 C lower than the dissolution temperature) in order to provide terephthalic acid crystals having an increased degree of purity.
Additionally, as evidenced by the table on p 3 of Standard Oil, one having ordinary skill in the art would have recognized that when dissolving terephthalic acid in water, the amount of water needed to dissolve a given quantity of terephthalic acid increases as the temperature of the water decreases. Given that the relationship between terephthalic solubility and water temperature was known in the art, it would have been well within the level of skill in the art to determine an appropriate quantity of water for dissolving a given quantity of terephthalic acid at a given water temperature. It would have been obvious to the person having ordinary skill in the art, therefore, to have carried out the recrystallization step in the process of modified England by determining and utilizing any appropriate quantity of water which dissolves the desired quantity of terephthalic acid at a selected temperature, including a quantity of water within the presently claimed range of 30-60 parts by weight based on 1 part by weight of copolymer.
As to claim 9, modified England suggests a process according to claim 7, as set forth above. As set forth above, England discloses washing the terephthalic acid with successive portions of water to remove occluded soluble salts (col 4, lines 56-59), but does not indicate the volume or quantity of water used in the washing step. However, one would have recognized that as the quantity of water used to wash England’s solid terephthalic acid product increases, the amount of impurities (e.g., occluded soluble salts) washed away by the water increases, and therefore the degree of the purity of the desired terephthalic acid substance increases. However, one would have also understood that as the volume of water used to wash a substance increases, the efficiency (in terms of, e.g., time, consumption of water, and production wastewater) of a purification process decreases. It would have been obvious to the person having ordinary skill in the art, therefore, to have utilized any appropriate amount of water in England’s washing step in order to achieve a desired reduction in impurities balanced with a desired process efficiency, including a volume of water within the presently claimed range.
As to claim 13, England discloses that the amount of sodium hydroxide is at least stoichiometric based on the terephthalyl values to be recovered, but not in excess of about 10% over stoichiometric. England teaches that less than stoichiometric results in incomplete saponification, while more than 10% over stoichiometric results in formation of undesirable degradation products which cause discoloration (col 1, lines 50-64). A stoichiometric amount of sodium hydroxide relative to 1 mole of terephthalic acid to be recovered is 2 moles of sodium hydroxide, because each terephthalic acid has two carboxylic groups, and therefore a stoichiometric amount of sodium hydroxide, as taught by England, falls within the presently claimed range of 2.3 moles or less. It would have been obvious to the person having ordinary skill in the art to have utilized 2 moles of base (sodium hydroxide) relative to 1 mole of terephthalic acid in the copolymer, as taught by England, in order to achieve complete saponification while avoiding the formation of undesirable degradation products.
Claim(s) 7-9 and 14 is/are rejected under 35 U.S.C. 103 as being unpatentable over Smuda (US 6239310) in view of Taylor et al (US 3574727), Standard Oil Company (GB 1152575) and Zubrick (The Organic Chem Lab Survival Manual; 1988, John Wiley and Sons, pp 91-110).
As to claims 7, 8 and 14, Smuda discloses heating polyethylene terephthalate (PET, i.e., a polymer synthesized from terephthalic acid) with a reagent substance in aqueous solution (col 2, lines 12-18), after which the PET is “digested” (corresponding to the presently recited “depolymerization reaction” carried out in the presence of water, as recited in claims 7 and 14), resulting in an aqueous solution of terephthalic acid salts (col 2, lines 19-21).
Smuda teaches filtering, neutralization and separation of terephthalic acid (col 2, lines 20-25 and lines 49-51), corresponding to the presently recited step of removing a diol component (i.e., by separating it from the terephthalic acid).
Smuda teaches washing the terephthalic acid with water (col 2, lines 25 and 53-54). The water used for the step of washing disclosed by Smuda corresponds to a solvent as recited in claims 7 and 8. Smuda does not disclose the use of heated water for the washing step, and therefore, at least the use of room temperature water (~25 C, which falls within the claimed range of 20-100 C) for the washing step would have been immediately envisaged by one having ordinary skill in the art.
Smuda further discloses crystallization of terephthalic acid from water (col 2, lines 26 and 54). However, Smuda fails to provide conditions for crystallization of terephthalic acid from water, and therefore, fails to teach the presently recited steps of dissolving and recrystallizing the washed terephthalic acid.
One having ordinary skill in synthetic chemistry would have recognized that recrystallization is a common purification technique: a desired (impure) substance is dissolved in a solvent, and the solution is then cooled to a temperature at which the desired substance precipitates from the solution in the form of crystals. The crystals of desired substance can then be separated from the solvent and from impurities, which remain dissolved in the solvent, such as by filtration and washing of the desired crystals. If evidence is needed that this basic knowledge is known to one of ordinary skill in the art, see Zubrick’s Chapter on Recrystallization starting on p 91, particularly, the discussion at the top of p 92 (points 1-3) and the bottom of p 97.
Taylor discloses a process for purifying crude terephthalic acid (col 1, lines 21-22). Taylor discloses that a further reduction in impurities in recovered terephthalic acid can be realized by recrystallizing from water. Taylor discloses heating to a temperature between 240-280 C with sufficient pressure to maintain the water in a liquid state. The terephthalic acid is dissolved in the heated solution, and then subsequently cooled to room temperature so as to precipitate additionally purified terephthalic acid, which may be recovered by filtration (col 3, lines 61-73).
Standard Oil also discloses the purification of aromatic polycarboxylic acids (p 1, lines 11-16), and teaches that because terephthalic acid has low solubility in water, either large volumes of water or high temperatures are required in order for the desired terephthalic acid quantity to be put into solution (p 2, line 126 to p 3, line 4). Standard Oil provides a table showing the amounts of terephthalic acid which can be dissolved in 100 g of water at temperatures ranging from 365-522 F (i.e., 185-272 C).
Considering the level of ordinary skill in the art and the disclosures of Taylor and Standard Oil as set forth above, one would have known generally suitable conditions for the recrystallization of terephthalic acid using water as a solvent in order to remove impurities from terephthalic acid. When carrying out the recrystallization of terephthalic acid in water, the person having ordinary skill in the art would have been motivated to select an appropriate temperature for heating terephthalic acid in water (such as within a range of 185-272 C as in Standard Oil, or 240-280 C, as in Taylor) in order to dissolve the terephthalic acid in a given volume of water. The person having ordinary skill in the art would have been subsequently motivated to slowly cool the solution to any appropriate temperature at which terephthalic acid is no longer soluble in water (and at which the undesired impurities remain soluble in water) in order to precipitate/crystallize the terephthalic acid while keeping impurities dissolved in the solvent. It would have been obvious to the person having ordinary skill in the art, therefore, to have carried out Smuda’s disclosed step of crystallizing terephthalic acid by dissolving terephthalic acid in water at any appropriate temperature within Standard Oil’s range of 185-272 C (including a temperature which falls within the presently claimed range of 200-220 C), and by then slowly cooling the aqueous solution to any appropriate temperature at which terephthalic is insoluble in water (including a temperature which is 50 to 200 C lower than the dissolution temperature) in order to provide terephthalic acid crystals having an increased degree of purity.
Additionally, as evidenced by the table on p 3 of Standard Oil, one having ordinary skill in the art would have recognized that when dissolving terephthalic acid in water, the amount of water needed to dissolve a given quantity of terephthalic acid increases as the temperature of the water decreases. Given that the relationship between terephthalic solubility and water temperature is known in the art, it would have been well within the level of skill in the art to determine an appropriate quantity of water for dissolving a given quantity of terephthalic acid at a given water temperature. It would have been obvious to the person having ordinary skill in the art, therefore, to have carried out the recrystallization step in the process of modified Smuda by determining and utilizing any appropriate quantity of water which dissolves the desired quantity of terephthalic acid at a selected temperature, including a quantity of water within the presently claimed range of 30-60 parts by weight based on 1 part by weight of copolymer.
As to claim 9, modified Smuda suggests a process according to claim 7, as set forth above. Smuda teaches that the product is “washed with distilled water” (col 2, line 52), but does not indicate the volume or quantity of water used in the washing step. One having ordinary skill in the art would have recognized that a washing step as taught by Smuda is performed in order to remove impurities from the surface of a solid desired product. One would have recognized that as the quantity of water used to wash the solid product increases, the amount of impurity washed away by the water increases, and therefore the degree of the purity of the desired substance increases. However, one would have also understood that as the volume of water used to wash a substance increases, the efficiency (in terms of, e.g., time, consumption of water, and production wastewater) of a purification process decreases. It would have been obvious to the person having ordinary skill in the art, therefore, to have utilized any appropriate amount of water in Smuda’s washing step in order to achieve a desired reduction in impurities balanced with a desired process efficiency, including a volume of water within the presently claimed range.
Response to Arguments
Applicant's arguments filed 3/13/2026 have been fully considered.
Applicant argues that none of England (remarks p 5, last paragraph), Taylor (remarks p 6, first paragraph), Standard Oil (remarks p 6, paragraphs 2-3) or Smuda (p 8, first full paragraph) teach a method according to the present claims, particularly in view of the presently recited conditions of dissolving and recrystallizing terephthalic acid. However, the rejections are based on a combination of references to show that it would have been obvious to the person having ordinary skill in the art to have modified primary reference England (or primary reference Smuda) to arrive at a method as presently recited, including the presently recited recrystallization conditions. One cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986). Because Applicant’s argument does not address the specific manner in which the cited references were combined with each other in the rejections of record to establish obviousness, Applicant’s argument that none of the cited references teach the presently recited method is not sufficient to overcome the rejections.
Applicant argues that Table 1 of the instant specification shows that recrystallization utilizing a dissolution temperature of 205 C (Example 1) exhibits superior purification efficiency compared to a recrystallization utilizing a dissolution temperature of 250 C (Example 2).
However, as noted in the objection to the specification above, Table 1 contains an error: the quantity of water used in example 2 is 10 times the PET mass, not 100 times the PET mass. Based on the disclosure in Standard Oil (i.e., that because terephthalic acid has low solubility in water, either large volumes of water or high temperatures are required in order for the desired terephthalic acid quantity to be put into solution (p 2, line 126 to p 3, line 4), instant examples 1 and 2 appear to show an expected result: at the lower temperature used for instant example 1 (205 C), substantially more water (50 times) was required to dissolve and recrystallize the terephthalic acid than at the higher temperature used for instant example 2 (250 C/10 times water). Applicant has not explained why the difference in impurity IPA concentrations between instant examples 1 and 2 is an unexpected difference.
Additionally, it is not possible to determine whether any difference in impurities between instant examples 1 and 2 is a result of differences in recrystallization conditions. The examples are not otherwise identical: for instance, example 1 performs depolymerization in ethylene glycol (p 33 line 29 to p 34 line 1), while example 2 performs depolymerization in water (p 35, lines 12-15). Example 1 contains a step of dissolving filtrate in water prior to neutralizing in HCl (see p 34, lines 6-8); this step is not performed in example 2. Because there are multiple unfixed variables between examples 1 and 2, it is not possible to assess the extent to which the IPA contents of the examples were affected by a difference in dissolution/recrystallization conditions.
Finally, Applicant is advised that evidence of nonobviousness must be commensurate in scope with the claims which the evidence is offered to support. See MPEP 716.02(d). Applicant has provided an example showing impurity concentrations when recrystallization is carried out using 205 C and 50x water, however, the instant claims encompass temperatures ranging from 200-220 C, and water quantities of 30x-60x. Applicant has not provided any data for temperatures within the claimed range other than 205 C, and has not provided any data for water quantities within the claimed range other than 50x.
Additionally, instant example 1 is carried out using a specific waste PET which must contain at least some isophthalic residues; in contrast, the instant claims encompass processes for recycling any (co)polymer comprising at least one terephthalic acid residue, and are not limited to recycling copolymers which contain isophthalic impurities. Instant example 1 further depolymerizes utilizing ethylene glycol and NaOH, followed by dissolution in water and filtration through activated carbon, prior to neutralizing in HCl and washing to remove NaCl. In contrast, instant claim 1 is not limited to any particular depolymerization solvent, is not limited to process using a base/NaOH, and does not recite any step of dissolving/filtration through activated carbon and neutralizing in HCl.
If Applicant wishes to overcome the present rejection by showing unexpected results, Applicant must provide sufficient evidence to show that unexpected results would be obtained for all species encompassed by the present claims. Applicant has not overcome the present rejection by showing unexpected results for at least the reason that applicant has not provided sufficient evidence to show that the alleged unexpected results would be obtained for all species encompassed by the present claims.
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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to RACHEL KAHN whose telephone number is (571)270-7346. The examiner can normally be reached Monday to Friday, 8-5.
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/RACHEL KAHN/Primary Examiner, Art Unit 1766
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