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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 February 05, 2026 has been entered.
Priority
Applicant’s claim for the benefit of a prior-filed application (has PRO 63019940, filed on 04 May 2020, and is 371 of PCT/US2021/030460, filed on 03 May 2021) under 35 U.S.C. 119(e) or under 35 U.S.C. 120, 121, 365(c), or 386(c) is acknowledged.
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 text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
Determining the scope and contents of the prior art.
Ascertaining the differences between the prior art and the claims at issue.
Resolving the level of ordinary skill in the pertinent art.
Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 28, 34, 41-42 and 44 are rejected under 35 U.S.C. 103 as being unpatentable over BAE et al. (KR101250310B1, hereinafter BAE) in view of WANG et al. (US20120080380A1, hereinafter WANG).
Regarding Claim 28, BAE discloses a polyamide reverse osmosis membrane using a polysulfone support containing carbon nanotubes, in which carbon nanotubes are introduced into the polysulfone support layer, followed by formation of a polyamide active layer by interfacial polymerization, to improve the overall water permeability of the membrane (¶[0001]).
The manufacturing method produces the polysulfone membrane containing multi-walled carbon nanotubes by adding surface-treated multi-walled carbon nanotubes to an organic solvent such as N-methyl pyrrolidone (NMP) or dimethylformamide (DMF), dispersing the multi-walled carbon nanotubes, adding polysulfone to the carbon nanotube/NMP solution, stirring to produce a carbon nanotube solution, removing air bubbles, casting the solution on the nonwoven fabric (i.e., a porous substrate) using a casting knife, and immersing the coated nonwoven fabric in distilled water to perform phase inversion and form the polysulfone/carbon nanotube membrane (¶[0016]).
As a matter of general practice and common sense in membrane fabrication, casting the carbon nanotube solution on the porous nonwoven fabric and performing phase inversion distributes the carbon nanotube solution throughout the porous substrate during membrane formation.
The resulting polysulfone support containing multi-walled carbon nanotubes is then impregnated with an aqueous solution of metaphenylenediamine (MPD), immersed in an organic solution of trimesoyl chloride (TMC) to form the polyamide selective layer, washed, and dried (¶[0017]).
FIG. 1 illustrates diagrams for the polyamide reverse osmosis membrane using the polysulfone/carbon nanotube support and the shape and form of the polyamide reverse osmosis membrane (¶[0020]).
PNG
media_image1.png
291
641
media_image1.png
Greyscale
FIG. 1 of KR101250310B1
The carbon nanotube discussion identifies both single-walled carbon nanotubes and multi-walled carbon nanotubes, and remains neutral toward the use of single-walled carbon nanotubes while describing multi-walled carbon nanotubes as economical fiber additives having composite-modifying effects (¶[0042]).
However, BAE does not explicitly disclose the use of single-walled carbon nanotubes.
WANG discloses a similar reverse osmosis membrane incorporating carbon nanotubes to improve water flux while maintaining salt rejection performance (¶[0002]).
The membrane includes a polyamide selective layer formed on a porous polysulfone support by interfacial polymerization, in which the porous support is contacted with an aqueous solution of nucleophilic monomers and then coated with an organic solution of electrophilic monomers to form a thin film at the interface (¶¶[0009]–[0010]).
The interfacial polymerization reaction uses m-phenylenediamine (MPD) as the preferred nucleophilic monomer and trimesoyl chloride (TMC) as the preferred electrophilic monomer (¶¶[0013], [0015]). The porous base support is preferably a polysulfone membrane selected for desirable mechanical and chemical properties (¶[0018]).
In Comparative Example 3, single-walled carbon nanotubes (SWCNTs) were used in the organic coating solution during interfacial polymerization to form the polyamide selective layer. The resulting membranes showed increased permeability compared to membranes fabricated without carbon nanotubes (¶[0036]).
The single-walled carbon nanotubes disclosed by WANG have smaller outer diameters than the larger-diameter multi-walled carbon nanotubes used in the comparative examples, and provide improved A-values in thin-film composite reverse osmosis membranes (¶[0036], Table 1). In view of the polysulfone membrane containing multi-walled carbon nanotubes, a person skilled in the art would have used the single-walled carbon nanotubes in place of the multi-walled carbon nanotubes to predictably improve A-values in the reverse osmosis membrane.
Therefore, it would have been obvious to a person having ordinary skill in the art, prior to the effective filing date of the claimed invention, to use the single-walled carbon nanotubes, as disclosed by WANG, in place of the multi-walled carbon nanotubes in the composite membrane fabrication method by BAE.
Regarding Claim 34, modified BAE makes obvious the method of forming a filtration membrane of Claim 28. BAE discloses the membrane layer is formed from a polysulfone solution containing carbon nanotubes (¶[0016]).
Regarding Claim 41, modified BAE makes obvious the method of forming a filtration membrane of Claim 28. BAE discloses forming a carbon nanotube/NMP solution by dispersing multi-walled carbon nanotubes in NMP, adding polysulfone to the carbon nanotube/NMP solution, stirring the solution, removing air bubbles, and casting the solution on the nonwoven fabric (¶[0016]). The carbon nanotube/NMP solution is reasonably considered a slurry because it contains dispersed carbon nanotubes in the polymer casting solution.
Regarding Claim 42, modified BAE makes obvious the method of forming a filtration membrane of Claim 28. BAE discloses that, after coating a substrate with a carbon nanotube-containing polysulfone solution, a polyamide coating is applied by impregnating the support with an aqueous solution of m-phenylenediamine and immersing the support in an organic solution of trimesoyl chloride (¶¶[0016]–[0017]).
Regarding Claim 44, modified BAE makes obvious the method of forming a filtration membrane of Claim 28. BAE discloses reverse osmosis desalination treatments such as seawater desalination and brackish water desalination (¶[0004]).
Regarding the limitation “winding the desalination membrane into a spiral membrane wound element; and installing the spiral membrane wound element into a desalination cartridge,” the limitation recites routine downstream packaging and assembly steps for using the formed reverse osmosis membrane in a desalination device. The claim does not recite any particular winding technique, cartridge structure, or assembly condition, and the record does not show criticality or unexpected results for the spiral-wound configuration formed by those steps (In re Dailey, 357 F.2d 669, 149 USPQ 47 (CCPA 1966); MPEP § 2144.04).
Claims 29-31 are rejected under 35 U.S.C. 103 as being unpatentable over BAE in view of WANG as applied to claim 28 above, and further in view of XU et al. (US20190275471A1, hereinafter XU).
Regarding Claims 29-31, modified BAE makes obvious the method of forming a filtration membrane of Claim 28. However, BAE does not explicitly disclose “the polymer matrix comprises polyimide,” “m-diaminophenylene,” and “n-methylpyrrolidone.”
XU discloses carbon molecular sieve (CMS) membranes for gas separation, particularly CMS membranes produced from polyimide materials (¶[0001]).
A dope solution comprises polyimide and polar aprotic solvents such as N-methyl-2-pyrrolidone (NMP), with about 10–40 wt% polyimide (¶[0027]). Aromatic polyimides are formed by reacting a dianhydride and a diamine via a polyamic acid intermediate. Suitable diamines include meta-phenylenediamine (m-PDA), para-phenylenediamine, and 2,4-diaminotoluene (¶¶[0030]–[0031]).
The dope solution disclosed by XU provides a membrane-forming polyimide solution in N-methyl-2-pyrrolidone (NMP), where NMP solubilizes the polyimide and meta-phenylenediamine (m-PDA) is a suitable diamine for forming the polyimide (¶[0027], ¶¶[0030]–[0031]). In view of modified BAE’s composite membrane fabrication method using a carbon nanotube/NMP solution, a person skilled in the art would have used the polyimide/NMP dope solution as the polymer matrix solution in place of the polysulfone/NMP solution to predictably improve thermal stability while maintaining an NMP-based casting solution for mixing the carbon nanotubes into the polymer matrix.
Therefore, it would have been obvious to a person having ordinary skill in the art, prior to the effective filing date of the claimed invention, to use the dope solution comprising polyimide and N-methylpyrrolidone (NMP), with the polyimide formed from m-diaminophenylene, as disclosed by XU, as the polymer matrix solution in the composite membrane fabrication method by modified BAE.
Claims 32 and 33 are rejected under 35 U.S.C. 103 as being unpatentable over BAE in view of WANG and XU as applied to claim 29 above, and further in view of MCCUTCHEON et al. (US20150060364A1, hereinafter MCCUTCHEON).
Regarding Claims 32 and 33, modified BAE makes obvious the method of forming a filtration membrane of Claim 29. The substrate in modified BAE is the nonwoven fabric on which the carbon nanotube solution is cast (¶[0016]). However, modified BAE does not explicitly disclose that the substrate comprises “polyester” and “polypropylene or polyethylene.”
MCCUTCHEON discloses composite membrane structures having a thin film ion rejecting layer supported by a membrane substrate (¶[0003]). The porous support material may comprise a nonwoven, woven, or extruded material selected from the group consisting of polypropylene, polyester, polyethylene, and combinations thereof (¶[0019]).
The nonwoven fabric materials disclosed by MCCUTCHEON provide known porous support materials for thin film composite membrane structures due to their mechanical durability, solvent resistance, and compatibility with membrane casting processes. In view of modified BAE’s nonwoven fabric substrate in the composite membrane fabrication method, a person skilled in the art would have used polyester, polypropylene, or polyethylene as the nonwoven fabric material to provide a known porous support material with predictable results.
Therefore, it would have been obvious to a person having ordinary skill in the art, prior to the effective filing date of the claimed invention, to use the substrate material comprising polyester, polypropylene, or polyethylene, as disclosed by MCCUTCHEON, in the composite membrane fabrication method by modified BAE.
Claim 35 is rejected under 35 U.S.C. 103 as being unpatentable over BAE in view of WANG as applied to claim 34 above, and further in view of BEAVERS et al. (US20180126337A1, hereinafter BEAVERS).
Regarding Claim 35, modified BAE makes obvious the method of forming a filtration membrane of Claim 34. However, modified BAE does not explicitly disclose that the polymer matrix further comprises chloroform.
BEAVERS discloses gas separation systems that use polymer membranes as selective barriers, valued for their low energy consumption, modularity, and scalability (¶[0004]). In one embodiment, polysulfone is dissolved in chloroform to form a 5 wt% casting solution for membrane fabrication (¶[0048]).
The chloroform casting solution disclosed by BEAVERS provides a known solvent system for dissolving polysulfone to form a membrane casting solution. Chloroform has a lower boiling point than common polar aprotic solvents, facilitating faster solvent evaporation during film formation and control over membrane morphology, including asymmetric structures and skin layer formation. In view of modified BAE’s polysulfone casting solution in the method of forming a filtration membrane, a person skilled in the art would have used chloroform as the solvent to predictably dissolve polysulfone for membrane fabrication.
Therefore, it would have been obvious to a person having ordinary skill in the art, prior to the effective filing date of the claimed invention, to use chloroform as the solvent in the membrane casting solution, as disclosed by BEAVERS, in the composite membrane fabrication method by modified BAE.
Claims 36 and 37 are rejected under 35 U.S.C. 103 as being unpatentable over BAE in view of WANG, as applied to claim 34 above, and further in view of MCCUTCHEON.
Regarding Claims 36 and 37, modified BAE makes obvious the method of forming a filtration membrane of Claim 29. The substrate in modified BAE is the nonwoven fabric on which the carbon nanotube solution is cast (¶[0016]). However, modified BAE does not explicitly disclose that the substrate comprises “polyester” and “polypropylene or polyethylene.”
MCCUTCHEON discloses composite membrane structures having a thin film ion rejecting layer supported by a membrane substrate (¶[0003]). The porous support material may comprise a nonwoven, woven, or extruded material selected from the group consisting of polypropylene, polyester, polyethylene, and combinations thereof (¶[0019]).
The nonwoven fabric materials disclosed by MCCUTCHEON provide known porous support materials for thin film composite membrane structures due to their mechanical durability, solvent resistance, and compatibility with membrane casting processes. In view of modified BAE’s nonwoven fabric substrate in the composite membrane fabrication method, a person skilled in the art would have used polyester, polypropylene, or polyethylene as the nonwoven fabric material to provide a known porous support material with predictable results.
Therefore, it would have been obvious to a person having ordinary skill in the art, prior to the effective filing date of the claimed invention, to use the substrate material comprising polyester, polypropylene, or polyethylene, as disclosed by MCCUTCHEON, in the composite membrane fabrication method by modified BAE.
Claims 38 and 40 are rejected under 35 U.S.C. 103 as being unpatentable over BAE in view of WANG as applied to claim 28 above, and further in view of SMALLEY et al. (US20040223901A1, hereinafter SMALLEY).
Regarding Claims 38 and 40, modified BAE makes obvious the method of forming a filtration membrane of Claim 28. WANG discloses that the single-walled carbon nanotubes used in membrane fabrication have an outer diameter of less than 2 nm (¶[0036]). However, modified BAE does not explicitly disclose that the single-walled carbon nanotubes are synthesized using a high pressure carbon monoxide process or include “a small diameter of 0.6 nm to 1.6 nm.”
SMALLEY discloses gas-phase nucleation and growth of single-walled carbon nanotubes using a high-pressure carbon monoxide process (¶[0002]). The process involves supplying high pressure carbon monoxide and a catalyst precursor gas to a mixing zone to initiate and grow single-walled carbon nanotubes by the Boudouard reaction (¶¶[0018]–[0019]). The resulting nanotubes are single-walled and have small diameters in the range of 0.6 nm to 0.8 nm, including (5,5) tubes (¶¶[0016]–[0017]). The disclosed diameter range falls within the claimed “small diameter of 0.6 nm to 1.6 nm.”
The HiPco-synthesized single-walled carbon nanotubes disclosed by SMALLEY provide a known source of high-purity single-walled carbon nanotubes produced at industrial scale with minimal by-products or solid contaminants. The process uses gaseous reactants and provides reproducible control over nanotube diameter (¶¶[0013]–[0014], ¶¶[0018]–[0019]). These attributes make HiPco-synthesized SWCNTs well-suited for integration into polymer-based membrane fabrication systems. In view of modified BAE’s method of forming a filtration membrane, a person skilled in the art would have used the HiPco synthesis process to predictably obtain high-purity, small-diameter single-walled carbon nanotubes for the casting solution.
Therefore, it would have been obvious to a person having ordinary skill in the art, prior to the effective filing date of the claimed invention, to incorporate the high-pressure carbon monoxide synthesis process, as disclosed by SMALLEY, to produce the single-walled carbon nanotubes used in the composite membrane fabrication method by modified BAE.
Claim 43 is rejected under 35 U.S.C. 103 as being unpatentable over BAE in view of WANG as applied to claim 28 above, and further in view of MCGINNIS et al. (US20180345228A1, hereinafter MCGINNIS).
Regarding Claim 43, modified BAE makes obvious the method of forming a filtration membrane of Claim 28. However, modified BAE does not explicitly disclose that "the substrate comprises a tricot film."
MCGINNIS discloses semipermeable membranes used in osmotically driven membrane separation systems, which rely on the movement of draw solutes through one or more support layers to effect separation (¶[0003]). In one embodiment, a support polymer is cast directly onto a tricot-type mesh support material, forming a bilayer substrate that becomes part of the final membrane. The tricot mesh conducts fluid flow within a finished membrane module and serves as the base or core for the membrane barrier layer (¶[0033]).
The tricot-type mesh disclosed by MCGINNIS provides structural reinforcement during processing, reduces creasing and wrinkling, increases membrane performance and manufacturing yields, and supports production efficiencies by eliminating separate fabrication steps traditionally required for leaf sets, flow spacers, or permeate tubes (¶[0034]). In view of modified BAE’s nonwoven fabric substrate in the method of forming a filtration membrane, a person skilled in the art would have used a tricot-type mesh support material as the substrate to predictably provide a reinforced membrane support structure and improve processability during membrane fabrication.
Therefore, it would have been obvious to a person having ordinary skill in the art, prior to the effective filing date of the claimed invention, to use a tricot-type mesh support material, as disclosed by MCGINNIS, as the substrate in the composite membrane fabrication method by modified BAE.
Response to Arguments
Applicant’s arguments have been fully considered but they are not persuasive. See Remarks, filed on February 5, 2026. The rejection has been maintained and updated in view of Applicant’s amendments.
Applicant’s argument is directed to BAE’s use of a polysulfone carbon nanotube casting solution. This argument is not persuasive and is inconsistent with the pending claim set. Claim 28 recites the polymer matrix generically, and dependent claim 34 expressly recites that the polymer matrix comprises polysulfone. Thus, the pending claims expressly include the polysulfone-based embodiment that Applicant criticizes. BAE’s polysulfone-based casting solution is therefore within the scope of the pending claim set and does not identify a deficiency in the rejection.
Applicant’s argument is also directed to the assertion that BAE does not disclose the porous substrate absorbing the carbon nanotube composite solution throughout the porous substrate. This argument is not commensurate with the scope of claim 28. Claim 28 broadly recites coating a porous substrate with the carbon nanotube composite solution such that the porous substrate absorbs the carbon nanotube composite solution throughout the porous substrate. Claim 28 does not require a particular absorption mechanism, pore structure, membrane-forming condition, or measured degree of absorption. Applicant has not identified claim language requiring anything more than the coating and absorption relationship addressed in the rejection.
Applicant’s argument is further directed to the assertion that WANG does not disclose absorption of a single-walled-carbon-nanotube solution throughout a porous base support. This argument is not persuasive. WANG is relied upon for a similar reverse osmosis membrane fabrication method and the use of single-walled carbon nanotubes, while the substrate coating and absorption relationship is addressed by BAE. Even assuming single-walled carbon nanotubes and multi-walled carbon nanotubes may differ in dispersion, viscosity, loading, or interaction with the polymer solution, claim 28 does not recite those properties or require a different substrate-absorption relationship based on whether the carbon nanotubes are single-walled or multi-walled. Applicant has not shown that the use of single-walled carbon nanotubes changes the claimed substrate-absorption relationship or produces an unexpected result under the claim language. Accordingly, Applicant’s argument does not identify a valid deficiency in the rejection.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to TAK L. CHIU whose telephone number is (703)756-1059. The examiner can normally be reached M-F: 9:00am - 6:00pm (CST).
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, PREM C. SINGH can be reached at 571-272-6381. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/TAK L. CHIU/Examiner, Art Unit 1771
/KRISHNAN S MENON/Primary Examiner, Art Unit 1771
Prosecution Insights