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 12-20 are pending as amended on 5/18/2026. Claims 2, 3, 7 and 19 stand withdrawn from consideration.
The new grounds of rejection set forth below were necessitated by Applicant’s amendment to the independent claims reciting alternating, hard segment and soft segment ratios within particular ranges. These limitations were not previously recited. 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Any rejections and/or objections made in the previous Office action and not repeated below are hereby withdrawn.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.
Information Disclosure Statement
The information disclosure statements filed 5/4/2026 and 4/20/2026 fail to comply with 37 CFR 1.98(a)(3)(i) because they do not include a concise explanation of the relevance, as it is presently understood by the individual designated in 37 CFR 1.56(c) most knowledgeable about the content of the information, of each reference listed that is not in the English language. The struck-through references which are not in English have not been considered.
Claim Rejections - 35 USC § 103
Claim(s) 1, 4-6, 8, 9, 12-18 and 20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Wu et al (US 2006/0155099) in view of Marten et al (Studies on the enzymatic hydrolysis of polyesters. II. Aliphatic–aromatic copolyesters; Polymer Degradation and Stability 88 (2005) 371-381) and Antheunis et al (Autocatalytic Equation Describing the Change in Molecular Weight during Hydrolytic Degradation of Aliphatic Polyesters, Biomacromolecules 2010, 11, 1118–1124).
As to claims 1, 4-6, 12-18 and 20, Wu discloses biodegradable copolyester products which can be directly utilized in any application that requires biodegradable materials, including disposable tableware [0031] (corresponding to a biodegradable molded article, as presently recited). Wu discloses that the biodegradable polyester is a reaction product of an aromatic dicarboxylic acid, an aliphatic diol and an aliphatic dicarboxylic acid [0026], and exemplifies polyester formed from a reaction of 1,4-terephthalic acid (TA), 1,4-butyleneglycol (BDO) and adipic acid (AA) [0041] (i.e., the same monomers which form the presently elected species, PBAT; note that the polyester in Wu’s example 2 [0041] is formed without utilizing metal salt, branching agent, CNC, ester polyol diol/PCL or chain extender).
Wu teaches that aliphatic polyesters are biodegradable and will not pollute the environment, but have low heat resistance and unsatisfactory mechanical properties. In contrast, aryl groups improve physical properties and processability, but the biodegradable rate of the aliphatic polyesters decreases with an increase in the amount of the aryl group introduced [0006]. However, Wu fails to teach PBAT which has an alternating ratio, hard segment ratio, and soft segment ratio within the presently claimed ranges.
Marten teaches that aliphatic-aromatic copolyesters exhibit a complex micro-structure, since the presence of different monomers cause domains of different structural characteristics side by side in one polymer chain (p 372, lower left), and the mobility of the polymer chains is the major and general controlling factor for the biodegradability of polyesters (p 379, upper left). The melting point of the material depends on how tightly polymer chains are fixed in crystalline regions, and is correlated with the length of aromatic sequences in an aliphatic-aromatic copolymer (p 379, middle right): block copolyesters have long aromatic sequences, high melting temperature, and low degradation rate, while alternating copolyesters have a sequence length of one and consequently are degradable at a relatively high rate. In random copolyesters, the biodegradation rate decreases when the fraction of aromatic component increases because of the increase in high melting crystals which are formed by the interaction of aromatic units (p 380, left column).
In fig 3 on p 376, Marten shows the four types of segments (corresponding to the presently recited types of bonding structures) which occur in random BTA copolyesters. Marten’s ester type 1 is found in units corresponding to instant bonding structure 2, Marten’s ester types 2 and 3 are found in units corresponding to instant bonding structure 1, and Marten’s ester type 4 is found in units corresponding to instant bonding structure 3. See also figure 1 on p 374. A random PBAT (BTA) copolyester having a 50:50 ratio of terephthalic and adipic units has equivalent amounts of each ester type, i.e., 25% hard segments (TBT), 25% soft segments (ABA) and 50% alternating segments (TBA and ABT). In other words, a random PBAT-50:50 has an alternating ratio according to instant equation 1 of 0.50, a hard segment ratio according to instant equation 2 of 0.25, and a soft segment ratio according to instant equation 3 of 0.25, and therefore, a random PBAT-50:50 has alternating, soft and hard segment ratios within the presently claimed ranges.
Marten teaches that in an ideal random copolyester, the fraction of different ester bonds depends on the overall comonomer composition, which determines the average length of the aliphatic and aromatic sequences in the polymer (p 376, lower right). In an alternating copolymer, only ester types 2 and 3 exist, and in a block copolymer, ester types 1 and 4 dominate (paragraph bridging pp 376-377). Marten concludes that it is possible to predict the rate of biodegradation for many polyesters based on their melting point and the temperature present in the degradation environment (p 380, lower left), and that due to the negative correlation between melting point and degradation rate, it is necessary to compromise between the thermal properties of the biodegradable polyester needed for a certain product, and the rate of biodegradation necessary for a given application (p 380, upper right).
Considering Marten’s disclosure, when preparing a PBAT copolyester to be used in biodegradable products, the person having ordinary skill in the art would have been motivated to select both an appropriate ratio of aliphatic (adipic) to aromatic (terephthalic) units, as well as an appropriate degree of randomness, in order to provide a desired aromatic sequence length, a desired melting point, and consequently, a desired degradation rate at a given degradation temperature, depending on the thermal properties and rate of degradation needed for a given application. It would have been obvious to the person having ordinary skill in the art, therefore, to have produced a PBAT (composition and molded article), as taught by Wu, by selecting any appropriate ratio of adipic acid and terephthalic acid segments, as well as any appropriate degree of randomness, in order to achieve a desired thermal stability (melting point) balanced with a desired rate of biodegradation, including an A:T ratio and a degree of randomness corresponding to alternating, hard segment and soft segment ratios within the claimed ranges (e.g., a random copolymer having an adipic/terephthalic ratio of 50:50).
Modified Wu fails to teach a hydrolysis degree after one or three weeks (as recited in claim 12), an initial hardness and wet hardness (as recited in claim 5), wet hardness reduction rates or differences (as recited in claims 1, 4, 6, 13 and 14), and weight and volume swelling rates (as recited in claims 15-18 and 20).
However:
As established above, modified Wu suggests a random PBAT having alternating, soft segment and hard segment ratios within the claimed ranges and formed without utilizing metal salt, branching agent, CNC, ester polyol diol or chain extender, and which therefore has a polymeric structure which is the same as the structure of the PBAT described in the instant specification (and particularly, the presently elected species according to instant example 15). Wu teaches that aliphatic polyesters are biodegradable and will not pollute the environment, but have low heat resistance and unsatisfactory mechanical properties. Aryl groups improve physical properties and processability, but the biodegradable rate of the aliphatic polyesters decreases with an increase in the amount of the aryl group introduced [0006].
Antheunis similarly teaches that water will only penetrate into the amorphous domains of an aliphatic polyester, and cannot enter crystalline domains if present. Antheunis further teaches that hydrolysis of an ester bond under mild conditions can only occur when acid or base catalyzed. Carboxylic end groups in the polymer matrix catalyze hydrolysis, and when a polymer initially has a high amount of carboxylic end groups, the hydrolysis is accelerated from the very beginning of the degradation process (p 1118, paragraph bridging columns).
As evidenced by the disclosures in Wu, Marten and Antheunis discussed above, the ratio of terephthalic acid to adipic acid in PBAT was known in the art as a result effective variable which can be optimized depending on demands of a given application to achieve a desired balance between properties associated with terephthalic segments (e.g., increased crystallinity, heat resistance, melt strength) and properties associated with adipic segments (e.g., increased flexibility, biodegradation). As evidenced by Antheunis’ disclosure, the carboxylic end group concentration in an aliphatic polyester was also known in the art as a result effective variable which can be optimized in order to achieve a desired rate of hydrolysis from the beginning of the degradation process (i.e., as carboxyl concentration increases, hydrolysis rate increases).
The person having ordinary skill in the art would have recognized that for some applications, biodegradability and/or fast hydrolysis is of higher importance than thermal/mechanical properties such as rigidity and heat resistance, while for other applications, improved thermal/mechanical properties (such as hardness, crystallinity, heat resistance) are a higher priority than faster biodegradation/hydrolysis. Therefore, when synthesizing a PBAT for a molded article, the person having ordinary skill in the art would been motivated to select both an appropriate terephthalic/adipic ratio (and degree of randomness) and an appropriate carboxylic end group content, in order to achieve a desired balance between thermal/mechanical properties and biodegradability/hydrolysis, depending on the priorities and demands of a given application. It would have been obvious to the person having ordinary skill in the art, therefore, to have produced a PBAT (composition and molded article), as suggested by modified Wu, by selecting any appropriate carboxyl end group content (as taught by Antheunis), in order to achieve desired mechanical properties balanced with desired rates of biodegradation and hydrolysis, including a carboxyl end group content which results in a hydrolysis degree after one or three weeks, an initial hardness and wet hardness, wet hardness reduction rates or differences, and weight and volume swelling rates within the presently claimed ranges.
As to claims 8 and 9, modified Wu suggests a PBAT resin composition according to claims 1 and 4, as set forth above. Wu is silent as to the water contact angle and surface polarity of a block formed from the PBAT resin. However, as established above, the carboxylic acid concentration of PBAT was known in the art to be a result effective variable and obvious to optimize. Given that carboxylic acid groups are polar and hydrophilic, there is reasonable basis to conclude that increasing the concentration of carboxylic groups increases the surface polarity and decreases water contact angle of PBAT. For the reasons established above, it would have been obvious to the person having ordinary skill in the art to have produced a PBAT composition as suggested by modified Wu by selecting any appropriate carboxyl end group content in order to achieve desired rates of biodegradation and hydrolysis, including a carboxyl end group content corresponding to a water contact angle and a surface polarity within the presently claimed ranges.
Response to Arguments
Applicant's arguments filed 5/18/2026 have been fully considered.
Applicant argues (p 20) that none of the previously cited references disclose the alternating, hard segment and soft segment ratios which are now recited in the amended independent claims. Applicant’s argument is persuasive, and the rejection of record has been modified (previously cited secondary reference Mahata has been swapped with a new secondary reference to Marten) to address the newly recited limitations.
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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