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 .
Continued Examination Under 37 CFR 1.114
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 18 March 2026 has been entered.
Priority
Applicant’s claim for the benefit of a prior-filed application (371 of PCT/IB2018/059635, filed 04 December 2018, which has PRO 62/633247, filed 21 February 2018, PRO 62/621155, filed 24 January 2018, and PRO 62/594195, filed 04 December 2017) under 35 U.S.C. 119(e) or under 35 U.S.C. 120, 121, 365(c), or 386(c) is acknowledged.
Response to Amendments
Applicant’s amendments filed 18 March 2026 has been entered.
Claims 1, 14, and 16 have been amended; Claims 2, 3, 6-9, 12, 13, 15, 17-29, and 31-34 have been canceled; and new Claims 35 and 36 have been added. Claims 1, 4, 5, 10, 11, 14, 16, and 30-36 are pending.
Response to Arguments
Applicant’s arguments filed 18 March 2026 have been fully considered but are not persuasive.
Regarding “Huang reference (US 2017/0312703 A1)” (pg. 8-9), Applicant states that HUANG teaches that “the similarity in properties between Compound A and the polymer in Huang causes them to remain associated and distinct from Compound B” and concludes that “even if Huang mentions phase separation, the presence of the polymer in Huang is inducing a separation into a polymer-rich phase and a polymer-poor phase” and “even if Huang mentions phase separation, since Compound A and Compound B are mutually miscible in Huang, a phase separation into a polymer-rich phase and a polymer-poor phase is not induced by immiscibility of the Compound A and Compound B” (pg. 8, par. 4). Applicant further states that HUANG teaches an isotropic membrane structure which is differentiated from the claimed asymmetric structure: “since Huang uses a special structure requiring isotropic pores across the thickness that differs from asymmetric structures, Huang does not teach a porous asymmetric membrane” (pg. 9, par. 3), and further states HUANG does not teach spinodal decomposition (pg. 9, par. 3). Therefore, Applicant argues, HUANG fails to teach the claimed invention, specifically, “forming a porous asymmetric membrane after the exposure time by inducing phase inversion by immersing the film in a coagulation bath to solidify the one or more membrane materials, wherein the inducing spinodal decomposition is performed prior to immersing the film in the coagulation bath” (pg. 9, par. 3).
The Examiner respectfully disagrees. It is agreed that the HUANG reference discloses a polymer dissolved in Compound A and further discloses Compound B being miscible in Compound A at a first temperature above a critical temperature and being immiscible at a second temperature below the critical temperature. HUANG is simply describing a long-known process of phase inversion—in this case, spinodal decomposition (i.e., as characterized by rapid quenching from a high miscible temperature to a low immiscible temperature). It is unclear as to what the Applicant is arguing—if Applicant is critical of the described phase inversion process, Applicant is merely arguing against a natural and expected phenomenon when a homogeneous solution comprising solvent/non-solvent is rapidly (e.g., 5-15 seconds) quenched to a temperature below a critical temperature to induce phase separation of polymer into its more miscible component (in this case, Compound A) and out of its less miscible component (Compound B).
Even further, Applicant has seemingly mistakenly interpreted HUANG as teaching that the supporting layer comprises the entirety of the disclosed membrane, i.e., Applicant’s argument that the supporting layer is isotropic across the wall thickness and therefore teaches against the claimed invention seems to ignore the fact that HUANG also discloses layers surrounding the supporting layer, i.e., the first and second surfaces having very different pore structures. Because Applicant has not further defined or claimed what they consider to be their “asymmetric” structure, HUANG’s disclosure of a first layer, a supporting layer, and a second layer reads on the claimed asymmetric membrane structure.
Finally, regarding Applicant’s argument that HUANG fails to explicitly disclose “spinodal decomposition”, such a limitation is reciting a necessarily expected result from the practice of the claimed invention. Broadly speaking, spinodal decomposition is a phase inversion process wherein a homogeneous mixture of solvent/non-solvent is rapidly quenched to a temperature that relegates the mixture to an unstable spinodal region in its phase diagram. Indeed, HUANG teaches such a process; thus, the recitation of “spinodal decomposition” is necessarily met.
Regarding “Rasmussen Reference (US 2008/0027153 A1)” (pg. 9-11), Applicant states that “Rasmussen does not teach forming a porous asymmetric membrane after the exposure time by inducing phase inversion by immersing the film in a coagulation bath to solidify the one or more membrane materials, wherein the inducing spinodal decomposition is performed prior to immersing the film in the coagulation bath” (pg. 9, par. 4) and instead, RASMUSSEN requires an “inverse suspension polymerization process” (pg. 10, par. 3). Therefore, Applicant argues RASMUSSEN fails to disclose the above recited limitation of Claim 1 (pg. 10, par. 3).
Applicant further disagrees with the combination of HUANG and RASMUSSEN as being obvious to combine because “In Rasmussen, the nonpolar organic solvent is used for suspending the aqueous phase composition which includes the monomer mixture and solvent. The non-polar solvent in Rasmussen is not part of a homogenous solution of polymer, solvent, and non-solvent” (pg. 10, par. 4). Therefore, one of ordinary skill would not find it obvious to combine RASMUSSEN with HUANG (pg. 11, par. 1).
The Examiner respectfully disagrees. It must be noted that the RASMUSSEN reference is never relied on as a teaching prior art; instead, the Office action has referenced RASMUSSEN as providing evidentiary support. Furthermore, Applicant is seemingly reciting unreferenced sections of RASMUSSEN not relied on by the Office action. 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).
Regarding “Liang Reference (US 2013/0193075)” (pg. 11-12), Applicant states LIANG discloses a different process than Claim 1 (pg. 11, par. 3-4) and therefore, Applicant argues that “Liang does not teach forming a porous asymmetric membrane after the exposure time by inducing phase inversion by immersing the film in a coagulation bath to solidify the one or more membrane materials, wherein the inducing spinodal decomposition is performed prior to immersing the film in the coagulation bath” (pg. 11, par. 5).
The Examiner respectfully disagrees. It is noted that Applicant is referencing teachings by LIANG that are unrelated to the recited teachings referenced by the Office action. 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). LIANG was relied upon by the Office as a secondary reference teaching the use of DMF as a solvent for advantageously improving the solubility of polymers, such as PVDF, and for teaching the use of octane to advantageously improve the dispersion of polymers in solution to provide more uniform membrane formation. The prior art may certainly teach other limitations; these however, are unrelated and not relied upon in the pending rejection of the claims.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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) 1, 4, 5, 10, 11, 14, 16, and 30-36 is/are rejected under 35 U.S.C. 103 as being unpatentable over HUANG et al. (US 2017/0312703 A1) in view of LIANG et al. (US 2013/0193075 A1) with evidentiary support from RASMUSSEN et al. (US 2008/0027153 A1).
Regarding Claim 1, HUANG discloses a method for producing a flat membrane via thermally induced phase separation (i.e., a method of making a membrane; p0045).
First, a homogenous casting solution of a polymer component is prepared in a solvent system; said solvent system comprises compound A and compound B, wherein compound A is a solvent for the polymer component and compound B is a non-solvent for the polymer component (i.e., a solvent and a non-solvent; p0045; p0062). The polymer component is a vinylidene fluoride polymer (i.e., a hydrophobic polymer; p0067). Compound A and compound B mix homogeneously with each other at the dissolving temperature for the polymer component (i.e., contacting one or more membrane materials, a solvent, and a non-solvent at a first temperature sufficient to form a homogeneous solution; the solvent and non-solvent are miscible at the first temperature; p0045); said dissolving temperature is above the critical demixing temperature (p0055) and above the solidification temperature of the solvent system (p0045).
Then, the homogeneous casting solution (i.e., dissolved polymer component in the solvent system of component A and component B) is formed into a film on a forming tool at a temperature above the critical demixing temperature (i.e., casting the homogeneous solution at about the first temperature to form a film; p0068). The formed film is then placed onto a thermally conditionable carrier that has a temperature lower than the critical demixing temperature and the solidification temperature such that the formed film is cooled to induce a liquid-liquid phase separation into a polymer-rich phase and a polymer-poor phase to form a membrane structure (i.e., the film is exposed to the second temperature for an exposure time; p0069). Because HUANG disclosed that compound A is a good solvent for the polymer component and compound B is a non-solvent for the polymer component (i.e., “[a] non-solvent for the polymer component is generally understood within the context of the present invention to be a compound which does not dissolve the polymer component”; p0062), during the liquid-liquid phase separation, as the temperature of the homogeneous solution is lowered, the polymer compound will associate with the compound A solvent upon passing the critical demixing temperature and subsequently solidify after passing the solidification temperature, i.e., the resultant polymer-rich phase is considered to contain only the polymer component and compound A, and the polymer-poor phase is considered to contain only compound B (i.e., the solvent and non-solvent are… immiscible at the second temperature).
HUANG discloses a residence time on the conditionable carrier of 5 to 15 seconds (p0069). While such a disclosed time is outside the claimed range of “an exposure time of 30 seconds to 90 seconds”, it would be within the capabilities of one of ordinary skill in the art of membrane formation to optimize the residence time to achieve a desired membrane structure, e.g., HUANG only discloses such a residence time to be “preferab[le]”. Furthermore, it is well-known in the art that the duration of cooling is dependent on the cooling temperature and on specific membrane being formed, i.e., a longer phase separation time would result in a more defined membrane structure, and a higher temperature closer to the demixing temperature would require a longer duration to achieve the same effect. Where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation absent unexpected results or evidence indicating such optimum or workable ranges are critical (In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955); MPEP§2144.05). Thus, the instantly recited range of 30 seconds to 90 seconds would have been obvious to one of ordinary skill in the art.
Finally, the conditionable carrier with the formed membrane structure is immersed in a bath filled with a cooling medium to effectively form the desired porous flat membrane (i.e., by immersing the film in a coagulation bath to form a porous membrane; wherein the inducing spinodal decomposition is performed prior to immersing the film in the coagulation bath; p0073). HUANG further discloses compound A to be a solvent capable of dissolving a vinylidene fluoride polymer, e.g., an acetate (p0064), which is known to contain polar groups (i.e., a polar solvent).
HUANG is deficient in disclosing the polar solvent includes dimethylformamide, a non-polar non-solvent, or that the non-polar non-solvent includes an alkane.
LIANG discloses the preparation of an asymmetric membrane (p0056) wherein a solution comprising at least one polymer, at least one solvent, and at least one nonsolvent is prepared (p0057). The at least one polymer includes any suitable polymer, including polyvinylidene fluoride (p0046); the at least one solvent includes any solvent in which the at least one polymer is completely soluble, e.g., dimethylformamide (p0061); and the at least one nonsolvent includes alkanes, such as octane (p0062). Advantageously, such a solvent as dimethylformamide improves the solubility of the polymer in solution (RASMUSSEN, p0085); even further, dimethylformamide is one of the most commonly used solvents in membrane arts especially for hydrophobic polymers such as polyvinylidene fluoride. Advantageously, such a nonsolvent as alkanes, e.g., octane, allows for the better dispersion of the polymer in solution enabling more uniform membrane formation and greater control over the porosity characteristics of the resultant membrane (RASMUSSEN, p0085, p0086); even further, hydrophobic polymers such as polyvinylidene fluoride are known to be mostly insoluble in alkanes, and would be obvious to one of ordinary skill in the art to select to prepare a membrane resin solution of a solvent/non-solvent system. Thus, prior to the effective filing date of the claimed invention, one of ordinary skill in the art would have found it obvious to provide dimethylformamide polar solvent and a non-polar non-solvent alkane such as octane as taught by LIANG for the method taught by HUANG.
The limitations “inducing spinodal decomposition of dimethylformamide and the alkane in the film at a second temperature”, “wherein spinodal decomposition generates a surface layer having mesopores”, and “forming a porous asymmetric membrane after the exposure time… wherein the porous asymmetric membrane includes the surface layer connected to a bulk layer including macrovoids” are directed toward results necessarily expected from the practice of the recited method steps. A “whereby clause in a method claim is not given weight when it simply expresses the intended result of a process step positively recited.” Id. (quoting Minton v. Nat’l Ass’n of Securities Dealers, Inc., 336 F.3d 1373, 1381, 67 USPQ2d 1614, 1620 (Fed. Cir. 2003); MPEP §2111.04). Where a reference discloses the terms of the recited method steps, and such steps necessarily result in the desired and recited effect, the fact that the reference does not describe the recited effect in haec verba is of no significance because the reference meets the claim under the doctrine of inherency. The prior art teaches or makes obvious all active steps of the claimed method; these instant limitations are directed toward the expected result from the practice of these steps. Because the prior art discloses or makes obvious such active steps, these intended results are necessarily expected whether explicitly disclosed or not by the prior art. Furthermore, spinodal decomposition is considered a spontaneous process; so long as the prior art discloses or makes obvious the recited steps, such a phenomenon is expected to occur whether positively recited or not. “[T]he fact that a characteristic is a necessary feature or result of a prior-art embodiment (that is itself sufficiently described and enabled) is enough for inherent anticipation, even if that fact was unknown at the time of the prior invention.” (Toro Co. v. Deere & Co., 355 F.3d 1313, 1320, 69 USPQ2d 1584, 1590 (Fed. Cir. 2004); MPEP §2112 II).
Regarding the limitation that “a porous asymmetric membrane” is formed, it is noted that such a limitation is broad and could be reasonably interpreted in multiple ways. First, the term “asymmetric” could be interpreted as a membrane having a gradient or non-linear changes in membrane density along a perpendicular cross-section, e.g., a dense, thin skin layer followed by a relatively diffuse membrane body, and followed by a thick, dense supporting substrate. Second, the term “asymmetric” could be interpreted as having pore dimensions that changes throughout the depth of the membrane. Even further, an asymmetric pore gradient includes a linearly-changing pore gradient (i.e., where the pore size increases from top layer to bottom layer) or a non-linear gradient where pore sizes are independent of the depth.
In view of this interpretation, it is noted that HUANG discloses the resultant membrane fabricated from the disclosed process yields a relatively isotropic and homogeneous pore structure (with pores having an average diameter of less than 1 µm and preferably less than 0.5 µm; p0030) in the supporting layer to advantageously provide mechanical stability for the overall membrane (p0027). However, HUANG further discloses that this supporting layer does not account for the entirety of the membrane; only at least 80% of the membrane wall thickness comprise the isotropic/homogeneous supporting layer (p0026); HUANG further discloses a first surface and a second surface having different pore sizes and porosity (p0041-0043, p0119, p0120, p0125). Indeed, HUANG discloses that the pores of the second surface have a maximum diameter range of 0.5-3 µm and have different shapes and geometries than those in the supporting layer (p0041); and further, the pores in the first surface are larger and have a different surface porosity (p0042-0043). As such, it is evidently clear that HUANG discloses a porous asymmetric membrane as claimed given that the pore structure changes from the first surface, through the supporting layer, to the second surface.
Regarding Claims 4 and 5, modified HUANG makes obvious the method of Claim 1. HUANG further discloses the solvent system comprising compounds A and B has a homogenous state and a state with a miscibility gap; upon cooling below the critical demixing/phase separation temperature, the system phase separates into the polymer-rich and polymer-poor liquid phases (p0055; p0061). This phase separation temperature is disclosed to disclosed to be above 50°C (p0055); HUANG further discloses that the conditionable carrier is at a temperature range of 40 to 70°C (p0069) implying that the phase separation temperature is at least 70°C. These disclosed ranges overlap with the claimed ranges of the first temperature being greater than 75°C and the second temperature being less than 75°C and establishes cases of prima facie obviousness absent evidence of unexpected results (MPEP 2144.05).
Regarding Claim 10¸ modified HUANG makes obvious the method of Claim 1. HUANG further discloses the polymer component is polyvinylidene fluoride polymer (i.e., wherein the hydrophobic polymer includes polyvinylidene fluoride; p0059).
Regarding Claim 11, modified HUANG makes obvious the method of Claim 1. LIANG further discloses the alkanes include octane (i.e., wherein the alkane includes octane; p0062).
Regarding Claim 14, modified HUANG makes obvious the method of Claim 1. HUANG is deficient in explicitly disclosing the one or more membrane materials include cellulose acetate.
LIANG further discloses the suitable polymers in the preparation of asymmetric membranes includes any suitable hydrophobic polymer, including polyvinylidene fluoride and cellulosic polymers such as cellulose acetate (i.e., the one or more membrane materials include cellulose acetate; p0046). The claim would have been obvious to one of ordinary skill in the art because the substitution of one known element for another would have yielded predictable results (MPEP §2143.01 B).
Regarding Claim 16, HUANG discloses a method for producing a flat membrane via thermally induced phase separation (i.e., a method of making a membrane; p0045).
First, a homogenous casting solution of a polymer component is prepared in a solvent system; said solvent system comprises compound A and compound B, wherein compound A is a solvent for the polymer component and compound B is a non-solvent for the polymer component (i.e., a solvent and a non-solvent; p0045; p0062). The polymer component is polyvinylidene fluoride (i.e., wherein the one or more membrane materials include polyvinylidene fluoride; p0059). Compound A and compound B mix homogeneously with each other at the dissolving temperature for the polymer component (i.e., contacting one or more membrane materials, a solvent, and a non-solvent at a first temperature sufficient to form a homogeneous solution; p0045); said dissolving temperature is above the critical demixing temperature (p0055) and above the solidification temperature of the solvent system (p0045).
Then, the homogeneous casting solution (i.e., dissolved polymer component in the solvent system of component A and component B) is formed into a film on a forming tool at a temperature above the critical demixing temperature (i.e., casting the homogeneous solution at about the first temperature to form a film; p0068). The formed film is then placed onto a thermally conditionable carrier that has a temperature lower than the critical demixing temperature and the solidification temperature such that the formed film is cooled to induce a liquid-liquid phase separation into a polymer-rich phase and a polymer-poor phase to form a membrane structure (i.e., wherein the film is exposed to the second temperature for an exposure time; wherein the second temperature is a temperature below the upper critical solution temperature and below the first temperature; p0069). Because HUANG disclosed that compound A is a good solvent for the polymer component and compound B is a non-solvent for the polymer component (i.e., “[a] non-solvent for the polymer component is generally understood within the context of the present invention to be a compound which does not dissolve the polymer component”; p0062), during the liquid-liquid phase separation, as the temperature of the homogeneous solution is lowered, the polymer compound will associate with the compound A solvent upon passing the critical demixing temperature and subsequently solidify after passing the solidification temperature, i.e., the resultant polymer-rich phase is considered to contain only the polymer component and compound A, and the polymer-poor phase is considered to contain only compound B. The conditionable carrier with the formed membrane structure is immersed in a bath filled with a cooling medium to effectively form the desired porous flat membrane (i.e., immersing the film in a coagulation bath; p0073). HUANG further discloses compound A to be a solvent capable of dissolving a vinylidene fluoride polymer, e.g., an acetate (p0064), which is known to contain polar groups (i.e., a polar solvent).
HUANG discloses a residence time on the conditionable carrier of 5 to 15 seconds (p0069). While such a disclosed time is outside the claimed range of “an exposure time of 30 seconds to 90 seconds”, it would be within the capabilities of one of ordinary skill in the art of membrane formation to optimize the residence time to achieve a desired membrane structure, e.g., HUANG only discloses such a residence time to be “preferab[le]”. Furthermore, it is well-known in the art that the duration of cooling is dependent on the cooling temperature and on specific membrane being formed, i.e., a longer phase separation time would result in a more defined membrane structure, and a higher temperature closer to the demixing temperature would require a longer duration to achieve the same effect. Where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation absent unexpected results or evidence indicating such optimum or workable ranges are critical (In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955); MPEP§2144.05). Thus, the instantly recited range of 30 seconds to 90 seconds would have been obvious to one of ordinary skill in the art.
Regarding the limitation that the first temperature sufficient to form a homogenous solution being greater than 75°C and less than about 100°C, HUANG further discloses the solvent system comprising compounds A and B has a homogenous state and a state with a miscibility gap; upon cooling below the critical demixing/phase separation temperature, the system phase separates into the polymer-rich and polymer-poor liquid phases (p0055; p0061). This phase separation temperature is disclosed to disclosed to be above 50°C (p0055); HUANG further discloses that the conditionable carrier is at a temperature range of 40 to 70°C (p0069) implying that the phase separation temperature is at least 70°C. These disclosed ranges overlap with the claimed range of the first temperature sufficient to form a homogeneous solution is greater than 75°C and less than about 100°C and establishes cases of prima facie obviousness absent evidence of unexpected results (MPEP 2144.05).
Even further, such a “first temperature” is considered a result-effective variable that may be optimized by one of ordinary skill in the art. Where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation absent unexpected results or evidence indicating such optimum or workable ranges are critical (In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955); MPEP§2144.05). Absent additional limitations furthering the specific composition of the claimed membrane materials, one of ordinary skill in the art would find it obvious to choose a polymer mix and solvent system that remains homogeneous at least from 75°C to 100°C.
Regarding the limitation that a “second temperature” is less than 75°C, HUANG further discloses the solvent system comprising compounds A and B has a homogenous state and a state with a miscibility gap; upon cooling below the critical demixing/phase separation temperature, the system phase separates into the polymer-rich and polymer-poor liquid phases (p0055; p0061). This phase separation temperature is disclosed to disclosed to be above 50°C (p0055); HUANG further discloses that the conditionable carrier is at a temperature range of 40 to 70°C (p0069) implying that the phase separation temperature is at least 70°C. These disclosed ranges overlap with the claimed range of the second temperature being less than 75°C and establishes a case of prima facie obviousness absent evidence of unexpected results (MPEP 2144.05).
HUANG is deficient in disclosing (1) a non-polar non-solvent, (2) the non-polar non-solvent includes an alkane, or (3) the one or more membrane materials include polyvinylidene fluoride and cellulose acetate.
LIANG discloses the preparation of an asymmetric membrane (p0056) wherein a solution comprising at least one polymer, at least one solvent, and at least one nonsolvent is prepared (p0057). Suitable polymers in the preparation of asymmetric membranes include any suitable hydrophobic polymer, including polyvinylidene fluoride and cellulosic polymers such as cellulose acetate (p0046); LIANG further discloses the membrane can include a mixture of polymers (i.e., the one or more membrane materials include polyvinylidene fluoride and cellulose acetate; p0047). LIANG discloses the at least one solvent includes any solvent in which the at least one polymer is completely soluble, e.g., dimethylformamide (p0061); and the at least one nonsolvent includes alkanes, such as octane (p0062). Advantageously, such a solvent as dimethylformamide improves the solubility of the polymer in solution (RASMUSSEN, p0085); even further, dimethylformamide is one of the most commonly used solvents in membrane arts especially for hydrophobic polymers such as polyvinylidene fluoride. Advantageously, such a nonsolvent as alkanes, e.g., octane, allows for the better dispersion of the polymer in solution enabling more uniform membrane formation and greater control over the porosity characteristics of the resultant membrane (RASMUSSEN, p0085, p0086); even further, hydrophobic polymers such as polyvinylidene fluoride are known to be mostly insoluble in alkanes, and would be obvious to one of ordinary skill in the art to select to prepare a membrane resin solution of a solvent/non-solvent system. Thus, prior to the effective filing date of the claimed invention, one of ordinary skill in the art would have found it obvious to provide dimethylformamide polar solvent and a non-polar non-solvent alkane such as octane as taught by LIANG for the method taught by HUANG.
HUANG is deficient in explicitly disclosing the polar solvent includes dimethylformamide or the alkane includes octane. However, as noted earlier, LIANG discloses the at least one solvent includes any solvent in which the at least one polymer is completely soluble, e.g., dimethylformamide (p0061); and the at least one nonsolvent includes alkanes, such as octane (p0062). Advantageously, such a solvent as dimethylformamide improves the solubility of the polymer in solution (RASMUSSEN, p0085); even further, dimethylformamide is one of the most commonly used solvents in membrane arts especially for hydrophobic polymers such as polyvinylidene fluoride. Thus, prior to the effective filing date of the claimed invention, one of ordinary skill in the art would have found it obvious to provide dimethylformamide as the polar solvent as taught by LIANG for the method taught by HUANG.
The limitations “inducing spinodal decomposition of dimethylformamide and octane in the film at a second temperature” and “inducing phase inversion… to form a porous asymmetric membrane” are directed toward results necessarily expected from the practice of the recited method steps. A “whereby clause in a method claim is not given weight when it simply expresses the intended result of a process step positively recited.” Id. (quoting Minton v. Nat’l Ass’n of Securities Dealers, Inc., 336 F.3d 1373, 1381, 67 USPQ2d 1614, 1620 (Fed. Cir. 2003); MPEP §2111.04). Where a reference discloses the terms of the recited method steps, and such steps necessarily result in the desired and recited effect, the fact that the reference does not describe the recited effect in haec verba is of no significance because the reference meets the claim under the doctrine of inherency. The prior art teaches or makes obvious all active steps of the claimed method; these instant limitations are directed toward the expected result from the practice of these steps. Because the prior art discloses or makes obvious such active steps, these intended results are necessarily expected whether explicitly disclosed or not by the prior art. Furthermore, spinodal decomposition is considered a spontaneous process; so long as the prior art discloses or makes obvious the recited steps, such a phenomenon is expected to occur whether positively recited or not. “[T]he fact that a characteristic is a necessary feature or result of a prior-art embodiment (that is itself sufficiently described and enabled) is enough for inherent anticipation, even if that fact was unknown at the time of the prior invention.” (Toro Co. v. Deere & Co., 355 F.3d 1313, 1320, 69 USPQ2d 1584, 1590 (Fed. Cir. 2004); MPEP §2112 II).
Regarding the limitation of “a porous asymmetric membrane”, it is noted that such a limitation is broad and could be reasonably interpreted in multiple ways. First, the term “asymmetric” could be interpreted as a membrane having a gradient or non-linear changes in membrane density along a perpendicular cross-section, e.g., a dense, thin skin layer followed by a relatively diffuse membrane body, and followed by a thick, dense supporting substrate. Second, the term “asymmetric” could be interpreted as having pore dimensions that changes throughout the depth of the membrane. Even further, an asymmetric pore gradient includes a linearly-changing pore gradient (i.e., where the pore size increases from top layer to bottom layer) or a non-linear gradient where pore sizes are independent of the depth.
In view of this interpretation, it is noted that HUANG discloses the resultant membrane fabricated from the disclosed process yields a relatively isotropic and homogeneous pore structure (with pores having an average diameter of less than 1 µm and preferably less than 0.5 µm; p0030) in the supporting layer to advantageously provide mechanical stability for the overall membrane (p0027). However, HUANG further discloses that this supporting layer does not account for the entirety of the membrane; only at least 80% of the membrane wall thickness comprise the isotropic/homogeneous supporting layer (p0026); HUANG further discloses a first surface and a second surface having different pore sizes and porosity (p0041-0043, p0119, p0120, p0125). Indeed, HUANG discloses that the pores of the second surface have a maximum diameter range of 0.5-3 µm and have different shapes and geometries than those in the supporting layer (p0041); and further, the pores in the first surface are larger and have a different surface porosity (p0042-0043). As such, it is evidently clear that HUANG discloses a porous asymmetric membrane as claimed given that the pore structure changes from the first surface, through the supporting layer, to the second surface.
Regarding Claim 30, modified HUANG makes obvious the method of Claim 16. HUANG further discloses that membranes based on polyvinylidene fluoride are known in the art to utilize inorganic particles to advantageously adjust micropore size and improve tolerance of polymer and solvent (i.e., wherein the one or more membrane materials further include an inorganic material; p0012). Thus, prior to the effective filing date of the claimed invention, one of ordinary skill in the art would have found it obvious to provide inorganic material as taught by HUANG in the method made obvious by modified HUANG.
Regarding Claim 35, modified HUANG makes obvious the method of Claim 16. As noted earlier, spinodal decomposition is a spontaneous mechanism that occurs when a mixture is rapidly quenched and leads to a thermodynamically unstable spinodal region of the mixture’s phase diagram. Because the prior art has disclosed or made obvious all other process steps, the recited limitations of “wherein spinodal decomposition generates a surface layer having mesopores” and “wherein the porous asymmetric membrane includes the surface layer connected to a bulk layer including macrovoids” are directed toward results necessarily expected from the practice of the recited method steps. A “whereby clause in a method claim is not given weight when it simply expresses the intended result of a process step positively recited.” Id. (quoting Minton v. Nat’l Ass’n of Securities Dealers, Inc., 336 F.3d 1373, 1381, 67 USPQ2d 1614, 1620 (Fed. Cir. 2003); MPEP §2111.04). Where a reference discloses the terms of the recited method steps, and such steps necessarily result in the desired and recited effect, the fact that the reference does not describe the recited effect in haec verba is of no significance because the reference meets the claim under the doctrine of inherency. The prior art teaches or makes obvious all active steps of the claimed method; these instant limitations are directed toward the expected result from the practice of these steps. Because the prior art discloses or makes obvious such active steps, these intended results are necessarily expected whether explicitly disclosed or not by the prior art.
Regarding Claim 36, modified HUANG makes obvious the method of Claim 16. HUANG further discloses that a common cooling medium for a coagulation bath for PVDF is water (p0009).
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to RYAN B HUANG whose telephone number is (571)270-0327. The examiner can normally be reached 9 am-5 pm EST.
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/Ryan B Huang/Primary Examiner, Art Unit 1777
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