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 .
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 12/30/2025 has been entered.
Claims 1, 2, 4-7, 9 and 15 are pending as amended on 12/30/2025.
Any rejections and/or objections made in the previous Office action and not repeated below are hereby withdrawn.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.
Claim Rejections - 35 USC § 112
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
Claims 1, 2, 4-7, 9 and 15 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention.
Independent claim 1 (both as originally filed, and as presently amended) recites a process which comprises three “feeding” steps to form a polylactic acid (PLA). The specification as originally filed describes a process comprising the three recited “feeding” steps:
in the first “feeding” step, a first lactide (e.g., L-lactide) is introduced into a first polymerization reactor, such as by a first feed line;
in the second “feeding” step, the partially polymerized lactide product from the first reactor is fed into a second polymerization reactor (section);
in the third “feeding” step, a second lactide (e.g., containing D- or Meso-lactide) is introduced to the partially polymerized product, such as by a feed line between a first polymerization reactor and a second polymerization reactor.
Claim 1 has now been amended to introduce limitations drawn to transitioning from a first grade of PLA to a second grade of PLA by reciting “performing the same steps but with a different concentration of D and/or meso-lactide in the second lactide feed to form a second grade of polylactic acid…”
The specification as originally filed describes (p 3, lines 4-10) a process and reactor configuration wherein a second lactide feed is introduced after a first reactor section: in a transition, one does not have to wait for the material in the first reactor section to be renewed, only the material in the second reactor section has to be renewed. The specification as filed also describes (p 4, lines 20-30) a second lactide feed which comprises a certain weight percentage of a lactide (e.g., a certain wt% of D-lactide, or a certain wt% of meso-lactide). However, the specification as originally filed does not generally describe forming a second grade of PLA by performing or repeating the “same” three recited feeding steps, but with a different “concentration” of D and/or meso-lactide in a second feed.
The instant examples in the specification describe a process carried out in a reactor configuration comprising 1 CSTR and 2 PFR in series. L-lactide is fed to, and polymerized in, the CSTR and first PFR. The partially polymerized output from the first PFR is then fed to the second PFR. D/Meso lactide monomer is fed to the second PFR, along with the partially polymerized output. The instant examples further describe a plant wherein “there is one grade change with D content adjustment every week,” and the tables in the instant specification contain calculations regarding transition time and loss reduction. However, there does not appear to be any description of how the content of D/Meso lactide units changes to form a second PLA grade which has a D/meso content which differs from the D/meso content of the first PLA grade. Therefore, the specification as originally filed does not describe the newly recited subject matter for at least the reason that there is no description of repeating the “same” three recited feeding steps with a different concentration of D and/or meso-lactide in a second feed.
The presently amended claims are not limited to a process wherein the second grade of polylactic acid is formed by performing the “same” feeding steps in the same series of reactors. The claims further do not require the three initial steps and the three repeated steps to be performed continuously. The claims encompass, for example, a process wherein all reactants and a first PLA formed from initially carrying out the recited steps are entirely removed from the reactor(s) prior to “performing the same steps but with a different concentration of D and/or meso-lactide in the second feed…” Because there is no description in the specification as filed of a process wherein the initial three feeding steps and the repeated three feeding steps are performed in a different series of reactors, and no description of a process wherein all material from the formation of a first grade of PLA is removed from the reactors prior to repeating the three feeding steps, and because such processes are encompassed by the claims as presently amended, the subject matter as recited in the amended claims is not commensurate in scope with the process described in the specification as originally filed.
Claims 4-7, 9 and 15 are rejected for the same reasons set forth above in view of their dependency from claim 1. Independent claim 2 differs from claim 1 by swapping the type of lactide in the first feed from L-lactide to D-lactide, and swapping the type of lactide recited in the third feed from D and/or meso to L and/or meso. The processes recited in the independent claims are otherwise the same, and therefore the discussion above for claim 1 is equally relevant to claim 2.
Claims 1, 2, 4-7, 9 and 15 are 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 1 recites a third feeding step of “feeding a second lactide into the second polymerization reactor section between the first polymerization reactor section and the second polymerization reactor section…” It is not clear how the feeding of the second lactide feed could be both “into the second polymerization reactor section,” AND “between the first polymerization reactor section and the second polymerization reactor section…” (emphases added). For examination purposes, claim 1 has been interpreted as drawn to a process carried out in a reactor configuration which comprises at least a first polymerization reactor section (for polymerizing “first” L-lactide) and a second polymerization reactor section (for reacting the polymerized first lactide output from the first reactor with a “second” D/meso lactide) connected in series. The third “feeding” step has been interpreted as a step of feeding the second lactide into the reactor configuration after (downstream of) the output of the first polymerization reactor section and before (upstream of) the second polymerization reactor section, and reacting/polymerizing the output of the first polymerization reactor section and the second lactide in the second polymerization reactor section.
Claims 4-7, 9 and 15 are rejected for the same reasons set forth above in view of their dependency from claim 1. Independent claim 2 differs from claim 1 by swapping the type of lactide in the first feed from L-lactide to D-lactide, and swapping the type of lactide recited in the third feed from D and/or meso to L and/or meso. The processes recited in the independent claims are otherwise the same, and therefore the discussion above for claim 1 is equally relevant to claim 2.
Additionally, claim 7 depends on claim 1 and further limits “the polylactic acid…” However, claim 1 has been amended to recite a first grade of polylactic acid and a second grade of polylactic acid. It is unclear whether “the polylactic acid” recited in claim 7 refers to the first grade, second grade, or both grades.
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.
Claim 5 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 5 depends on claim 1 and recites an embodiment wherein the first lactide feed is essentially free of L-lactide. However, claim 1 requires that the first lactide feed comprises L-lactide. Therefore, claim 5 fails to properly further limit claim 1. 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
Claim(s) 1, 2, 4-7, 9 and 15 is/are rejected under 35 U.S.C. 103 as being unpatentable over Rafler et al (WO 200906222A1; previously included machine translation cited herein), with Ouchi et al (US 2008/0097074) cited as an evidentiary reference for claim 7.
As to claims 1, 4, 9 and 15, Rafler discloses L-lactic copolyesters whose properties are controlled mainly by the composition of the monomers used and their comonomer and block length distribution in the polymer. The block copolyesters are prepared by continuous two-step ring-opening polymerization of L,L-lactide with one or more aliphatic heterocycle comonomers (translation p 5, bottom half).
Rafler teaches each of two stages carried out in a separate apparatus. The first stage is carried out in a high mixing intensity reactor to produce uniform block lengths of L-lactide monomers (A blocks). The second stage is carried out in a twin-screw extruder, where comonomers are added to the melt of the poly-L-lactic acid blocks (p 6, upper half). The reactive extrusion system for the synthesis is shown in figure 1 (see translation p 10, top; image copied from original document):
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In the process taught by Rafler and shown in figure 1, the “dosage L,L-dilactide” (5) into “prereactor” (1) corresponds to the presently recited first step of feeding a first L-lactide feed into a first polymerization reactor section. The prereactor (1) corresponds to the first section recited in claim 15, and the line from (5) to (1) corresponds to the first feeding line recited in claim 15.
The “dosage of poly-L-lactide melt” (6) into twin screw extruder (2) corresponds to the presently recited second step of feeding the output of the first polymerization reactor section (i.e., poly-L-lactide) into a second polymerization reactor section [wherein the portion of Rafler’s twin screw extruder downstream of the inlet for (7) corresponds to the presently recited “second polymerization reactor section”]. The line from (6) to (2) corresponds to the feeding line for feeding the output of the first reactor section into the second polymerization reactor section or between the first and second reactor sections, as recited in claim 15.
The introduction of comonomer via “dosage comonomers” inlet (7) corresponds to the presently recited step of feeding a second lactide feed between the first polymerization reactor section (i.e., Rafler’s (1)) and the second polymerization reactor section (i.e., the portion of Rafler’s extruder (2) downstream of (7)), such that the comonomers (second lactide feed) are then fed into the second polymerization reaction section. The line from (7) to (2) corresponds to the “second lactide feeding line” recited in claim 15.
In Rafler’s example 2 (see p 10, lower half), the comonomer metered in via (7) is entirely (i.e., 100 wt%) meso-lactide, which meets the instant requirement (see instant claims 1 and 9) that the second lactide feed comprises at least 40 wt% D/meso-lactide and at least 30 wt% meso-lactide.
As to the recitation that the feeding of meso-lactide occurs after at least 30% and at most 95% of the total residence time:
Rafler teaches pure lactic acid block copolyesters having a formula wherein both Block A and Block B are ring-opened units of lactide monomers, wherein the molar fraction of A blocks ranges from 1-99%, wherein the number of monomer units in each of the A and B blocks (“m” and “n”) ranges from 5 to 1000, and wherein the number of blocks “p” ranges from 1 to 100. Rafler teaches that the composition of the blocks is controllable by the structure of the comonomers as well as the polymerization technology, and that relationships between material properties and block length are known in the art (p 7, top half). See also p 8, where Rafler discloses monitoring the course of polymerization via monomer conversion and molar masses of samples taken off, and, teaches that the copolymer composition is adjusted by the molar ratio of the starting monomers and the number of monomers in the blocks is controlled by comonomer reactivity and technology of the ring-opening polymerization and extrusion technique.
Rafler discloses that in the first stage, L-lactide is polymerized to form first (A) blocks of poly-L-lactide. Unreacted L-lactide is still present in the second stage when the comonomer which forms the B blocks is metered in. In the second stage, the introduction and polymerization of the comonomer with the poly-L-lactic blocks and unreacted lactide, as well as transesterifications, leads to formation of further block structures. See page 6, top half.
Rafler fails to specifically teach that the feeding of B-block comonomer (e.g., meso-lactide as in Example 2) occurs after any particular percentage of total residence time.
However, considering Rafler’s disclosure, one having ordinary skill in the art would have recognized that as polymerization of L-lactide in the first stage progresses, the degree of conversion increases and the content of unreacted L-lactide in the poly-L-lactic acid A block transferred to the second stage decreases. One having ordinary skill in the art would have further recognized that both reaction temperature and reaction duration influence polymer molecular weight, degree of conversion, and occurrence of transesterification reactions within a formed polymer product. Therefore, given Rafler’s recognition that polymer material properties depend on polymer block length, the person having ordinary skill in the art would have been motivated to select appropriate temperatures and durations for each of the first and second stages of Rafler’s disclosed process in order to achieve block lengths, a degree of conversion, and an overall polymer molecular weight corresponding to a desired set of properties tailored for an intended application. Therefore, when preparing a block copolyester comprising A blocks formed from L-lactide and B blocks formed from meso-lactide (such as in Rafler’s example 2), it would have been obvious to the person having ordinary skill in the art to have selected any appropriate temperature and duration for Rafler’s first stage (polymerization of L-lactide) and any appropriate temperature and duration for Rafler’s second stage (feeding and polymerization of meso-lactide with the poly-L-lactic acid and L-lactide produced in the first stage), including durations of the first and second stages which correspond to feeding of the meso-lactide after at most 95% (or at most 90% as recited in claim 4) of the total residence time, and further including durations which correspond to feeding the meso-lactide after at least 30% of the total residence time.
As to the recitation of transitioning from a first PLA grade to a second PLA grade comprising a different D content by performing the same steps but with a different concentration of D and/or meso-lactide:
Rafler teaches that isomer-free poly-L-lactic acid is semicrystalline with a high melting point, while poly-D,L-lactic acid composed of equimolar L and D monomers is amorphous with lower softening temperature and modulus (p 3, top half). Rafler provides a Table (Table 1 on p 3) showing the influence of D monomer content on the properties of poly-L-lactide (as D content increases, melting temperature decreases). Rafler teaches that polymer properties are a function of copolymer composition, which can be adjusted by the ratio of the comonomers used (p 6, first paragraph). Rafler teaches that the comonomers can be added in the second stage extruder in a readily controllable manner to the melt of PLA blocks (p 6, third paragraph). Rafler further teaches that the products can be used for fibers, films, foams and injection molded articles (p 7, top half).
Considering Rafler’s disclosure regarding the ability to control addition of second monomers to influence polymer properties, one having ordinary skill in the art would have been motivated to carry out Rafler’s process to obtain a desired amount of a first polylactide copolymer having a certain D-content associated with properties suited for a first application taught by Rafler (e.g., fiber formation), and, to repeat Rafler’s disclosed process to obtain a desired amount of a second polylactide having a different D-content, in order to provide an additional (second) PLA product having different properties suited for a second application taught by Rafler (e.g., foam or injection molding). It would have been obvious to the person having ordinary skill in the art, therefore, to have repeated the steps of forming a polylactide, as suggested by Rafler, in order to form a PLA product having a different D content (and different properties suited to a different application) compared to a previously formed PLA product, thereby arriving at the presently claimed process.
As to claim 2, Applicant has stated on the record (see remarks filed on 8/11/2025, p 10) that there is no difference in inventive merit or technical contribution whether L-lactide or D-lactide is fed to the first reactor, and the distinction between L-lactide and D-lactide does not materially affect the scope or inventive concept of the claims. Given Applicant’s clear admission on the record that a process as claimed wherein the first lactide feed is L-lactide and the second lactide feed is meso-lactide (as in claim 9) is not patentably distinct from a process as claimed wherein the first lactide feed is D-lactide and the second lactide feed is meso-lactide (as encompassed by claim 2), claim 2 is unpatentable over Rafler for the same reasons set forth above with respect to claim 9.
As to claims 5 and 6, Rafler discloses that the stirred reactor in the first stage is charged with L-L lactide (see examples 1 and 2 on p 10). Rafler also discloses that in the first stage “pure poly-L-lactic acid blocks A are produced…” (p 5, second paragraph). Therefore, Rafler discloses a process wherein the first lactide feed is entirely L-lactide (i.e., free of D-lactide, as recited in claim 5, and free of meso-lactide, as recited in claim 6).
As to claim 7, Rafler does not characterize the block copolymer produced as a stereo-block copolymer. Moreover, Rafler exemplifies a copolymer produced from L-lactide and 10 mol% meso-lactide having a melting point of 165 C (example 2, p 10), as well as a copolymer produced from L-lactide and 15 mol% meso-lactide having a melting point of 158 C (example 4, p 11). Considering that Rafler does not disclose formation of stereocomplex crystals, and further considering that stereocomplex crystals are characterized by a higher melting point than those exemplified by Rafler (i.e., between 190-240 C; see, e.g., US 2008/0097074 paragraph [0020]), there is reasonable basis to conclude that Rafler’s block copolymers are not stereo-block copolymers.
Response to Arguments
Applicant's arguments filed 12/30/2025 have been fully considered
Applicant argues (p 7) that Rafler is only concerned with static copolymer composition rather than with a dynamic grade switching in a continuous process, and therefore Rafler does not teach modification of the second lactide feed entry to reduce off-spec product or shorten transition time. Applicant’s argument fails to overcome the rejection over Rafler for at least the reason that the amended claims are not limited to a continuous process in which there is a “dynamic grade switching.”
Applicant argues (p 7) that Rafler does not address the challenge of minimizing off-specification product during grade transitions. The instant specification establishes that excess production of off-spec product during grade transitions is a problem associated with a known process wherein L-lactide monomer is mixed with a fixed content of D- and/or meso-lactide comonomer before feeding to the reactors (p 1, lines 23-26). However, Rafler does not disclose a process wherein a fixed content of comonomer is mixed with L-lactide before feeding to the reactors.
Rather, as set forth in the rejection of record, Rafler discloses a reactor configuration and reaction sequence as recited in the present claims and described in the instant specification, wherein L-lactide is polymerized to poly-L-lactide in a first reactor section, and wherein second lactide monomer (e.g., meso-lactide) is fed to the reactor system downstream of the first reactor section, such that the second lactide and poly-L-lactide are combined and subsequently reacted in a second reactor section. The fact that Rafler is silent as to problems associated with grade changes in a process which differs from the process disclosed by Rafler fails to establish the non-obviousness of the present claims. Applicant’s argument (p 7) that Rafler provides no teaching to modify the entry of the second lactide feed in order to reduce off-spec product is unpersuasive because it is not necessary to modify the entry of second lactide feed in Rafler: Rafler discloses entry of the second lactide feed as presently recited. Therefore, no modification to Rafler’s reactor configuration is needed to arrive at the presently recited reactor configuration and timing/location of second lactide feed (which Applicant alleges results in minimizing of off-specification product during grade transitions).
Applicant argues (pp 7-8) that instant example 2 demonstrates unexpected results. Applicant alleges that Table 2 illustrates a case in which the second lactide feed is introduced after 75 minutes of a total residence time of 120 minutes, resulting in a 70% reduction in transition time compared to a case where the second lactide is introduced at 0% of the total residence time. However, the instant comparative example is not representative of Rafler because, as adequately discussed above, Rafler does not teach a process where the second lactide is incorporated from the beginning, i.e., at 0% of the total residence time. Therefore, for at least the reason that the instant comparative case is not representative of the closest prior art, Example 2 fails to establish unexpected results.
The examiner further notes that there is insufficient detail in instant Table 2 to determine the actual timing for the introduction of the D/Meso lactide. The example describes a reaction configuration with 1 CSTR (30 minutes) and 2 PFRs (90 minutes). There is no indication that the residence time in each of the 2 PFRs is the same, and therefore it cannot be presumed that the second lactide feed is introduced after 45 minutes in the first PFR. Additionally, instant example 2 provides an illustration of a specific reactor configuration (1 CSTR and 2 PFR reactors) with specific volumes, operated at specific feed rates, temperatures, etc. And although not described, a specific protocol must have been followed for changing the D-content. In contrast, the present claims are not limited to any type(s) of reactor(s), reactor volume(s), feed rate(s) or polymerization conditions. Evidence of nonobviousness must be commensurate in scope with the claims which the evidence is offered to support. See MPEP 716.02(d). Therefore, 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 processes encompassed by the present claims.
Applicant argues (p 8) that paragraph 24 of the final office action contains an erroneous interpretation of Rafler’s table 3. The discussion of Rafler’s table 3 in paragraph 24 was in response to Applicant’s argument that Rafler’s table 3 teaches away from the presently claimed residence time range. The discussion asserted that Rafler’s table 3 was likely not representative of Rafler’s reactive extrusion process. Applicant appears to agree that the experiments in Rafler’s table 3 are not representative of a process which is carried out using lactide feeds at different polymer reactor sections (such as in Rafler’s figure 1). For at least the reason that experiment 3 is not a reactive extrusion process, Applicant’s argument that the comonomer feed timing shown in Rafler’s table 3 teaches away from the presently claimed residence time range is unpersuasive. Moreover, disclosed examples and preferred embodiments do not constitute a teaching away from a broader disclosure or nonpreferred embodiments (MPEP 2123).
Applicant further maintains the argument that Table 3 shows a single feeding event wherein D-lactide is fed after 7.5 minutes, which Applicant argues is 18.75% of the total residence time of 40 minutes. In the event that the Table 3 experiment is considered to have relevance to Rafler’s reactive extrusion process, the examiner notes that Rafler characterizes Table 3 as showing stepwise monomer dosing, and therefore theexaminer disagrees that the experiment includes a single feeding event of D-lactide after 7.5 minutes. However, Rafler’s description of the Table 3 experiment is insufficiently clear to support a conclusion that Rafler teaches away from addition of a comonomer feed at any time other than at 18.75% of the total residence time.
Conclusion
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
