DETAILED ACTION
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 .
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION. —The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 1-18 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.
Independent claims 1 and 11 define R1 and R2 as being selected from, inter alia, “C1-20 alkyl,” while the depicted polymer structure requires R1 and R2 to function as divalent linking groups within the polymer backbone. Further claim 4 recites that R1 is -CH2CH2- and R2 is -CH2, which are divalent alkaline groups rather than monovalent alkyl groups. It is therefore unclear whether “alkyl” is intended to encompass alkylene linking groups, and the metes and bounds of the claimed polymer structure cannot be determined with reasonable certainty.
Claims 10-15 recites that the IL cross-linking agent is present in an amount of 1 to 25 mol% relative to the total amount of IL and PIL. The claims do not specify whether the molar amount of the PIL is based on moles of polymer chains, ionic repeating units, or starting monomer. These possible calculation bases produce materially different molar percentages, particularly because the PIL may have a degree of polymerization from 3 to 100,000. Accordingly, the same composition could satisfy or fail to satisfy the recited 1 to 25 mol% range depending on the calculation method selected, and the scope of the claims cannot be determined with reasonable certainty.
Claim 11 recites that “a non-polymerized IL is between the first and second layer,” without specifying whether the IL forms a discrete intermediate layer, is located at an interface, or is dispersed within the either layer. Because dependent claims 16 and 17 alternatively characterize the second layer as a PIL-containing layer or a mechanical support layer, the spatial relationship of the non-polymerized IL to the claimed layers is not ascertainable with reasonable certainty.
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 4 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 4 does not appear to specify a further limitation of claim 1. Claim 1 limits R1 and R2 to alkyl, alkenyl, alkynyl, aryl, and combinations thereof, whereas claim 4 recites divalent -CH2CH2- and -CH2 groups. Applicant is required to clarify the dependency or amend claim 1 to expressly include divalent alkylene groups. 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 non-obviousness.
Claims 1-10 are rejected under 35 U.S.C. 103 as being unpatentable over O’Harra et al., Polymers, April 2021 (hereinafter “O’Harra”) in view of Carlisle et al., Journal of Membrane Science, April 2012 (hereinafter “Carlisle”).
Regarding claim 1, O’Harra discloses vinylimidazolium-based poly (ionic liquid) membranes containing multivalent imidazolium additives and multivalent vinylimidazolium cross-linking agents for gas separation. O’Harra explains that the membranes are prepared from the vinyl-ionic-liquid monomer 1-n-butyl-3-vinylimidazolium, [C4vim][Tf2N], bis (trifluoromethylsulfonyl) imide, and that certain formulations are cross-linked using tri- and tetra-vinylimidazolium benzene ionic cross-linking agents (section 1, pp. 1-3; section 2.2, membrane synthesis; figs. 1-2; table 1).
For compact prosecution, R1 and R2 are interpreted broadly as encompassing the alkyl-, alkylene-, or alkenyl=type carbon linkages formed through viny polymerization. Any ambiguity is addressed separately under 35 U.S.C. 112(b) above. Under that interpretation, O’Harra’s poly[C4vim][Tf2N], reads on the claimed polymerized ionic-liquid formula. The butyl substituent falls within the claimed C1-20 alkyl genus; the unsubstituted imidazolium ring positions correspond to hydrogen; and [Tf2N]-, is an anion within the scope of X1. The disclosed polymer necessary contains at least three repeating units and therefore satisfies the recitation that n is an integer of at least 3.
O’Harra discloses two multivalent ionic cross-linking agents: [Tri(Vinylim*)XL][Tf2N], and [Tet(Vinylim*)XL][Tf2N] (section 2.2, pp. 4-6; figs. 1-2; table 1). O’Harra’s [Tri(Vinylim*)XL][Tf2N] corresponds to the second cross-linking agent structure recited in claim 1, while [Tet(Vinylim*)XL][Tf2N] corresponds to the tetra-imidazolium alternative recited in the Markush group. Because claim 1 requires a cross-linking agent “selected from the group consisting of” the depicted alternatives, disclosure of any one member is sufficient. O’Harra further discloses that the cross-linking agents contain multiple vinyl groups and become covalently incorporated into the polymer during UV-initiated free radical polymerization (section 2.2, membrane preparation; fig. 3). However, O’Harra fails to disclose, in the same cross-linked formulation, a separate non-polymerized ionic liquid.
Carlisle discloses a cross-linked poly(vinylimidazolium)-room-temperature ionic liquid (RTIL) gel membranes prepared by photopolymerizing an oligo (ethylene glycol)-functionalized, monofunctional N-vinylimidazolium RTIL monomer together with an oligo(ethylene glycol)-functionalized, difunctional bis-vinylimidazolium RTIL cross-linking monomer in the presence of a non-polymerizable “free RTIL” (see Abstract, page 24-28). Carlisle therefore teaches a composition comprising a polymerized ionic liquid, a non-polymerized ionic liquid, and a separately added ionic-liquid cross-linking agent, wherein polymerization of the difunctional cross-linking monomer produces the cross-linked poly(vinylimidazolium) network. Carlisle’s [emim][Tf2N] satisfies component (ii) because: R3 and R4 are methyl and ethyl, respectively, each within C1-20 alkyl; the remaining imidazolium ring positions are hydrogen; X2 is [Tf2N]-; and the RTIL remains non-polymerized and physically retained within the cross-linked polymer network.
Neither reference includes any zeolite or other inorganic molecular-sieve filler in any disclosed composite; both O’Harra and Carlisle are directed exclusively to organic PIL/IL/cross-linker chemistries, satisfying this limitation. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to incorporate Carlisle’s free non-polymerized [emim][Tf2N] free RTIL into O’Harra’s cross-linked poly [C4vim][Tf2N] membrane containing the tri- or tetra- vinylimidazolium cross-linking agent in order to increase the concentration of mobile, CO2-philic ionic-liquid species within the polymer matrix and thereby improve CO2 permeability while retaining the dimensional and mechanical stability supplied by O’Harra’s multivalent cross-linking agent. Carlisle teaches the relationship between increasing free-RTIL loading and increasingCO2 permeability, and O’Harra teaches the ionic content and cross-linker loading may be varied to tune gas-transport and mechanical properties.
Regarding claim 2 and 3, O’Harra an imidazolium poly (ionic liquid) prepared from 1-n-butyl-3-vinylimidazolium, [C4vim][Tf2N], together with multivalent vinylimidazolium cross-linking agents. The chemical structure of the imidazolium monomer and the multivalent imidazolium compounds are shown in figures 1 and 2. The carbon positions of the imidazolium rings are depicted without additional substituents and therefore bear hydrogen atoms.
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Regarding claim 5, Carlisle discloses the non-polymerized ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide, [emim][Tf2N] shown as RTIL 3 in figure 2 below (page 26). The two imidazolium nitrogen substituents are methyl and ethyl, thereby satisfying the recited R3 and R4 limitations.
Regarding claim 6 and 7, O’Harra’ disclose the PIL and the tri- and tetra- vinylimidazolium cross-linking agents with Tf2N- counterions (pp. 3-5). Carlisle discloses the non-polymerized ionic liquid [emim][Tf2N], shown as RTIL in figure 2 below. Thus, X1, X2, and A are each Tf2N-.
Regarding claim 8 and 9, Carlisle varied the loading of free RTIL ([emim][Tf2N]) relative to the PIL component at 45, 65, and 75 wt.% including membranes described as “homogenous” and “biphasic” compositions (page 26). While claims 8 and 9 recites 1-60 mol% and 1-40 mol% respectively relative to PIL, Carlisle disclosed composition window which spans from free RTIL loadings used comparison up through 75 wt.% overlaps the claimed range. Thus, Carlisle identifies the amount of non-polymerized IL as a result-effective variable affecting membrane permeability. It would have been obvious to optimize the amount of free IL, including selecting an amount within about 1-60/1-40 mol% relative to the PIL, through routine experimentation to obtain the desired balance of permeability and membrane stability.
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Regarding claim 10, Carlisle disclose that cross-linker concentration is a result-effective variable and evaluates cross-linked membranes containing 5 to 100 mol% difunctional cross-linking monomer (see abstract and page 28, left column), including amounts falling with in the claimed range. It would have been obvious to select a cross-linker concentration within the claimed range through routine optimization to obtain the desired balance of permeably, and selectivity.
Claims 11-18 are rejected under 35 U.S.C. 103 as being unpatentable over O’Harra et al., Polymers, April 2021 (hereinafter “O’Harra”) in view of Carlisle et al., Journal of Membrane Science, April 2012 (hereinafter “Carlisle”) in further view of Gin et al., WO 2019/232074 A1, December 05, 2019 (hereinafter “Gin”).
Regarding claim 11, O’Harra discloses vinylimidazolium-based poly (ionic liquid) membranes containing multivalent imidazolium additives and multivalent vinylimidazolium cross-linking agents for gas separation. O’Harra explains that the membranes are prepared from the vinyl-ionic-liquid monomer 1-n-butyl-3-vinylimidazolium, [C4vim][Tf2N], bis (trifluoromethylsulfonyl) imide, and that certain formulations are cross-linked using tri- and tetra-vinylimidazolium benzene ionic cross-linking agents (section 1, pp. 1-3; section 2.2, membrane synthesis; figs. 1-2; table 1).
For compact prosecution, R1 and R2 are interpreted broadly as encompassing the alkyl-, alkylene-, or alkenyl=type carbon linkages formed through viny polymerization. Any ambiguity is addressed separately under 35 U.S.C. 112(b) above. Under that interpretation, O’Harra’s poly[C4vim][Tf2N], reads on the claimed polymerized ionic-liquid formula. The butyl substituent falls within the claimed C1-20 alkyl genus; the unsubstituted imidazolium ring positions correspond to hydrogen; and [Tf2N]-, is an anion within the scope of X1. The disclosed polymer necessary contains at least three repeating units and therefore satisfies the recitation that n is an integer of at least 3.
O’Harra discloses two multivalent ionic cross-linking agents: [Tri(Vinylim*)XL][Tf2N], and [Tet(Vinylim*)XL][Tf2N] (section 2.2, pp. 4-6; figs. 1-2; table 1). O’Harra’s [Tri(Vinylim*)XL][Tf2N] corresponds to the second cross-linking agent structure recited in claim 1, while [Tet(Vinylim*)XL][Tf2N] corresponds to the tetra-imidazolium alternative recited in the Markush group. Because claim 1 requires a cross-linking agent “selected from the group consisting of” the depicted alternatives, disclosure of any one member is sufficient. O’Harra further discloses that the cross-linking agents contain multiple vinyl groups and become covalently incorporated into the polymer during UV-initiated free radical polymerization (section 2.2, membrane preparation; fig. 3). However, O’Harra fails to disclose, in the same cross-linked formulation, a separate non-polymerized ionic liquid positioned between the first selective layer and an opposing second layer.
Carlisle discloses a cross-linked poly(vinylimidazolium)-room-temperature ionic liquid (RTIL) gel membranes prepared by photopolymerizing an oligo (ethylene glycol)-functionalized, monofunctional N-vinylimidazolium RTIL monomer together with an oligo(ethylene glycol)-functionalized, difunctional bis-vinylimidazolium RTIL cross-linking monomer in the presence of a non-polymerizable “free RTIL” (see Abstract, page 24-28). Carlisle therefore teaches a composition comprising a polymerized ionic liquid, a non-polymerized ionic liquid, and a separately added ionic-liquid cross-linking agent, wherein polymerization of the difunctional cross-linking monomer produces the cross-linked poly(vinylimidazolium) network. Carlisle’s [emim][Tf2N] satisfies component (ii) because: R3 and R4 are methyl and ethyl, respectively, each within C1-20 alkyl; the remaining imidazolium ring positions are hydrogen; X2 is [Tf2N]-; and the RTIL remains non-polymerized and physically retained within the cross-linked polymer network. Neither reference includes any zeolite or other inorganic molecular-sieve filler in any disclosed composite; both O’Harra and Carlisle are directed exclusively to organic PIL/IL/cross-linker chemistries, satisfying this limitation.
Gin disclose a thin-film-composite membrane architection in which a poly(RTIL)-containing selective composition is cast on a porous support. Sin explains that conventional thin film-composite membrane casting causes the RTIL-containing casting solution to penetrate the porous support, resulting in selective-layer “soak-in” (page 4, lines 23-31). Gin further teaches that polymer- or prepolymer-based RTIL casting solutions are applied to ultrafiltration supports and that the extent of penetration into the support may be controlled (page 5, lines 11-17, and lines 20-27).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to incorporate Carlisle’s free non-polymerized [emim][Tf2N] free RTIL into O’Harra’s cross-linked poly [C4vim][Tf2N] membrane containing the tri- or tetra- vinylimidazolium cross-linking agent in order to increase the concentration of mobile, CO2-philic ionic-liquid species within the polymer matrix and thereby improve CO2 permeability while retaining the dimensional and mechanical stability supplied by O’Harra’s multivalent cross-linking agent. Carlisle teaches the relationship between increasing free-RTIL loading and increasingCO2 permeability, and O’Harra teaches the ionic content and cross-linker loading may be varied to tune gas-transport and mechanical properties. It would have been obvious to one of ordinary skill in the art to form O’Harra’s cross-linked imidazolium PIL composition as the selective first layer on Gin’s porous supporting second layer. Gin teaches applying poly(RTIL)-based gas-separation compositions to porous supports to form thin-film-composite membranes, thereby providing mechanical support while preserving a this pas-selective layer.
Regarding claim 12, Carlisle discloses that CO2 permeability is controlled by free-RTIL loading and cross-linker concentration and reports cross-linked poly(vinylimidazolium)/RTIL membranes having CO2 permeabilities substantially greater than 50 barrer, including a reported permeability of about 540 barrer for a membrane containing 75 wt.% free RTIL (sections 3.2 and 3.3.1, pages 30-31).
Regarding claim 13, O’Harra disclose imidazolium PIL membrane having a CO2/CH4 ideal selectivity of about 20.2, which exceeds the claimed minimum of 10 (see Abstract and Table 2).
Regarding claim 14, O’Harra’ disclose the PIL and the tri- and tetra- vinylimidazolium cross-linking agents with Tf2N- counterions (pp. 3-5). Carlisle discloses the non-polymerized ionic liquid [emim][Tf2N], shown as RTIL in figure 2 above. Thus, X1, X2, and A are each Tf2N-.
Regarding claim 15, Carlisle disclose that cross-linker concentration is a result-effective variable and evaluates cross-linked membranes containing 5 to 100 mol% difunctional cross-linking monomer (see abstract and page 28, left column), including amounts falling with in the claimed range. It would have been obvious to select a cross-linker concentration within the claimed range through routine optimization to obtain the desired balance of permeably, and selectivity.
Regarding claims 16, O’Harra is relied upon as above. Gin discloses applying poly(RTIL)-based selective compositions to porous supports and recognizes penetration of the composition into the support. (pages 4, lines 23-31; page 5, lines 11-17). It would have been obvious to one of ordinary skill in the art at the time of the invention to apply O’Harra’s cross-linked PIL composition to both opposing surfaces of Gin’s support, thereby forming opposing PIL/cross-linker layers with Carlisle’s free IL retained between them, to improve encapsulation and retention of the free IL while maintaining gas-selective surfaces.
Regarding claim 17, Gin discloses a thin-film composite membrane having a poly (RTIL)- containing selective layer cast on a porous membrane support. (Page 5, lines 11-17, and 20-27. The porous support mechanically supports the selective layer and therefore satisfies the requirement that the second layer is a mechanical support layer.
Regarding claim 18, O’Harra discloses cast cross-linked PIL membranes having measured thicknesses of approximately 122-237 µm, which fall entirely within the claimed range (section 2.4, composite and membrane fabrication).
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to MIRIAM N EZELUOMBA whose telephone number is (571)272-0110. The examiner can normally be reached Monday-Friday 8:00am-4:30pm.
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/M.N.E./Examiner, Art Unit 1776
/Jennifer Dieterle/Supervisory Patent Examiner, Art Unit 1776
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