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 .
Priority
Acknowledgment is made of applicant’s claim for foreign priority (KR10-2019-0076310, filed on 26 June 2019) under 35 U.S.C. 119 (a)-(d). Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55.
Claim Objections
Claim 1 objected to because of the following informalities:
The phrase “a pH thereof is 12 to 12.5” should be corrected to read “a pH of the composition is 12 to 12.5” to clarify the antecedent for “thereof”.
Appropriate correction is required.
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.
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.
Claims 1, 2, 4, and 13-15 are rejected under 35 U.S.C. 103 as being unpatentable over YOON et al. (High flux nanofiltration membranes based on interfacially polymerized polyamide barrier layer on polyacrylonitrile nanofibrous scaffolds, 2008, hereinafter YOON) in view of TOMSCHKE (US6464873B1).
Regarding Claim 1, 2 and 19, YOON discloses that polymeric membranes are widely used for water purification, and that reducing barrier layer selectivity permits nanofiltration at higher flux (Pg. 484).
In Fabricate polyamide barrier layer by interfacial polymerization, the thin film composite membranes were prepared on the PAN nanofibrous scaffold support and the PAN400 UF membrane support. Piperazine (i.e., Chemical Formula 2) and bipiperidine (i.e., Chemical Formula 1) dihydrochloride were dissolved in water, the total amine concentration ranged from 0.125% to 1% (w/v), and bipiperidine dihydrochloride ranged from 0% to 60% (w/w) with respect to the amount of piperazine. The support layers were wetted with the piperazine, bipiperidine, and triethylamine solution, NaOH was added to release free amine, and the trimesoyl chloride solution, 0.1% (w/v) in hexane, was introduced onto the amine impregnated support layer to form the polyamide barrier layer (§ 2.3, Pg. 486–487).
In Interfacial polymerizations using piperazine and bipiperidine with trimesoyl chloride on PAN UF membrane and PAN nanofibrous scaffold supports, the interfacial polymerization procedures shown in Fig. 2 were applied under the same conditions on both supports to evaluate permeation behavior. The experiments were carried out in cross flow mode using MgSO₄ at 2000 ppm at 70 psi, and the pressure dependencies were investigated over a pressure range of 70 to 190 psi (§ 3.2, Pg. 488-490).
Fig. 2 schematically illustrates the interfacial polymerization procedure using unsubstituted piperazine and 4,4′-bipiperidine, where the ring nitrogen positions correspond to “–NR″–” and the remaining ring positions correspond to “–CRR′–,” with R, R′, and R″ being hydrogen for the unsubstituted structures depicted. As for Claim 2, bipiperidine has —NR″— at R3 and R8, and piperazine has —NR″— at R12 and R15; the remaining labeled positions are CRR′ with R, R′, and R″ as hydrogen.
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Fig. 2 of YOON et al.
In Comonomer (bipiperidine) effect on the permeation performance of interfacially polymerized polyamide TFNC membranes, the permeation performance was evaluated using MgSO₄ at 2000 ppm at 70 psi with a cross-flow device. The total amine concentration was fixed at 1% (w/v), and the amount of bipiperidine was added up to 60% (w/w) with respect to the total amine concentration (§ 3.3, Pg. 490-491).
In Performance comparison between TFNC membranes and commercial NF membranes, the performances were compared under MgSO₄ 2000 ppm over a pressure range of 70 to 190 psi. At 70 psi, the rejection rates include BP/PIP PAN electrospun at 97.7% (§ 3.4, Pg. 491).
Based on the disclosure, in § 2.3, 60% (w/w) with respect to the amount of piperazine means the weight of bipiperidine is 60% of the weight of piperazine, so a = 0.60b. Using this disclosed ratio as a theoretical example in the claim’s formula (a/(a+b)) × 100% gives:
(0.60b/(0.60b + b))× 100% = (0.60/1.60)× 100% = 37.5%.
In § 3.3, the amount of bipiperidine was added up to 60% (w/w) with respect to the total amine concentration, which corresponds to 60% under the claim’s formula. Accordingly, the disclosed ratios correspond to 37.5% and 60%, which reads upon the claimed range of “30% to 60%”.
In § 2.3, the total amine concentrations ranged from 0.125% to 1% (w/v). Using this disclosed range as a theoretical example for dilute aqueous solutions, and using the bipiperidine to piperazine ratio:
a = 0.60b, at 0.30% (w/v) total amine
a + b = 0.30, and 0.60b + b = 0.30
1.60b = 0.30 ⇒ b=0.30/1.60= 0.1875 wt% (piperazine)
a = 0.60 × 0.1875 = 0.1125 wt% (bipiperidine)
Accordingly, bipiperidine is 0.1125 wt% and piperazine is 0.1875 wt%, wherein each read upon the claimed range of “0.1 wt% to 0.3 wt% based on a total weight of the composition”.
However, YOON does not explicitly disclose the aqueous solution having a pH of 12 to 12.5, nor the salt rejection being measured under conditions of 2,000 ppm of an aqueous MgSO₄ solution, a pressure of 130 psi, a temperature of 25°C, and 4 L/min, with a salt rejection of 99.7% or more.
TOMASCHKE discloses bipiperidine based polyamide, water permeable membranes for reverse osmosis and nanofiltration (Col. 1, Lns. 8–14).
In one embodiment, a microporous support is coated with a first aqueous solution containing a monomeric amine salt and a second aqueous solution containing bipiperidine, with the coating amount adjusted so that the molar ratio of the monomeric amine salt to bipiperidine is about 4 to about 12 (Col. 8, Lns. 12–27).
In order to save a step, the aqueous solution of the monomeric amine salt can also contain bipiperidine, with bipiperidine preferably present at about 0.15% w/v to about 0.5% w/v, the solution preferably adjusted to a pH of about 11 to about 13, and the molar ratio of the monomeric amine salt to bipiperidine preferably adjusted to about 4 to about 12 (Col. 8, Lns. 28–39). The disclosed aqueous solution is adjusted to a pH of about 11 to about 13, which overlaps the claimed aqueous composition pH range of “12 to 12.5.”
In Example 1, an aqueous solution comprising bipiperidine at 0.35% w/v is adjusted to a pH of about 12.75 by addition of sodium hydroxide, a polysulfone ultrafilter substrate is coated with the aqueous bipiperidine solution, and the substrate is contacted with a TMC hydrocarbon solution containing 0.55% w/v TMC to prepare a bipiperidine based polyamide membrane (Col. 9, Ln. 42–Col. 10, Lns. 12).
In Membrane Performance, membranes prepared in Membrane Preparation Examples 1 and 2 were tested for flux rate, salt rejection, and selectivity, including using an aqueous MgSO₄ feed solution having a concentration of 2000 ppm, and Table 1 reports MgSO₄ at 2000 ppm tested at 130 psig with Example 1 reporting a flux of 70 GFD and achieving a total salt rejection of 99.2% (Col. 10, Lns. 29–44; Table 1).
pH control of the aqueous amine phase is a known, routine interfacial polymerization condition for polyamide nanofiltration and reverse osmosis membranes, and is used to tune formation of the polyamide layer and its transport properties, as TOMASCHKE discloses adjusting bipiperidine containing aqueous solutions to an alkaline pH for membrane fabrication (Col. 8, Lns. 28–39). In view of YOON’s separation membrane formed by interfacial polymerization using an aqueous amine solution, a person skilled in the art would incorporate TOMASCHKE’s alkaline pH conditioning into YOON’s aqueous amine solution to achieve an aqueous solution pH within the claimed 12 to 12.5 range as part of routine tuning of the interfacial polymerization conditions.
Regarding the temperature condition of 25°C, this corresponds to normal room temperature, and experiments are routinely carried out at room temperature without producing any unexpected results from that condition, as YOON performs the interfacial polymerization at room temperature and TOMASCHKE does not indicate elevated test temperatures.
Regarding the flow rate condition of 4 L/min, this is a routine cross flow testing parameter selected for operating the test apparatus and does not impose additional structural limitations on the membrane, as YOON performs membrane performance testing in cross flow mode and TOMASCHKE performs similar membrane performance testing without indicating any non-routine flow rate requirement.
Regarding the claimed salt rejection of 99.7% or more, Table 1 of TOMASCHKE reports that the bipiperidine based polyamide membrane achieves a total salt rejection of 99.2% when tested using an aqueous MgSO₄ feed solution having a concentration of 2000 ppm at 130 psig (Col. 10, Lns. 29–44; Table 1). The claimed ≥99.7% salt rejection differs only in degree from the reported 99.2% and would have been obvious through routine optimization of YOON’s bipiperidine to piperazine ratio and alkaline pH conditioning of the aqueous amine phase to increase polyamide layer selectivity.
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 alkaline pH conditioning of the aqueous amine phase, as disclosed by TOMASCHKE, into the separation membrane of YOON.
Regarding Claim 4, modified YOON makes obvious a separation membrane of Claim 1. TOMASCHKE discloses an organic solvent for the acyl halide solution, including hexane (Col. 9, Lns. 3–12). In Example 1, the aqueous solution comprises bipiperidine at 0.35% w/v and sodium lauryl sulfate (SLS) at 0.375% w/v (Col. 9, Lns. 42–67). In a comparative membrane preparation, an aqueous solution with 0.25 wt% polyvinyl alcohol and 0.25 wt% piperazine is immersed in 1 wt% trimesoyl chloride in n-hexane at 25°C for 1 minute (Col. 10, Lns. 17–27).
Regarding Claim 13, modified YOON makes obvious a separation membrane of Claim 1. Based on the theoretical calculation for Claim 1:
Bipiperidine is 0.1125 wt%, which reads upon the claimed “Chemical Formula 1…0.11 wt% to 0.21 wt%”
Piperazine is 0.1875 wt%, which reads upon the claimed “Chemical Formula 2 …0.14 wt% to 0.25 wt%”
Regarding Claim 14, modified YOON makes obvious a separation membrane of Claim 13. YOON discloses the total amine concentration range of 0.125% to 1% (w/v) (§ 2.3, Pg. 486–487) and that bipiperidine is added up to 60% (w/w) with respect to the total amine concentration (§ 3.3, Pg. 490–491).
Although modified YOON does not explicitly disclose the specific paired bipiperidine/piperazine, namely 0.11 wt%/0.25 wt%, 0.14 wt%/0.21 wt%, 0.18 wt%/0.18 wt%, or 0.21 wt%/0.14 wt%, these weight percentages are result-effective variables that would have been obtained through routine optimization of YOON’s disclosed amine composition amounts:
0.11 wt% / 0.25 wt%: total amine = 0.11 + 0.25 = 0.36 wt%, within 0.125% to 1% (w/v), BP fraction = 0.11/0.36 = 30.6%, within up to 60%.
0.14 wt% / 0.21 wt%: total amine = 0.14 + 0.21 = 0.35 wt%, within 0.125% to 1% (w/v), BP fraction = 0.14/0.35 = 40%, within up to 60%.
0.18 wt% / 0.18 wt%: total amine = 0.18 + 0.18 = 0.36 wt%, within 0.125% to 1% (w/v), BP fraction = 0.18/0.36 = 50%, within up to 60%.
0.21 wt% / 0.14 wt%: total amine = 0.21 + 0.14 = 0.35 wt%, within 0.125% to 1% (w/v), BP fraction = 0.21/0.35 = 60%, within up to 60%.
A person skilled in the art would have arrived at these specific paired bipiperidine and piperazine wt% amounts through routine optimization by trial and error of result effective variables within YOON’s disclosed total amine concentration range and disclosed bipiperidine addition limit, where the claimed values differ only in degree from the disclosed values and no unexpected results are indicated (In re Aller, 220 F.2d 454, 456–57; 1955).
Regarding Claim 15, modified YOON makes obvious a separation membrane of Claim 1. Table 1 of TOMASCHKE reports that the bipiperidine based polyamide membrane of Example 1 achieves a flux of 70 GFD when tested at 130 psig (Col. 10, Lns. 29–44).
Claim 16 is rejected under 35 U.S.C. 103 as being unpatentable over YOON and TOMASCHKE as applied to claim 1 above, and further in view of YANG et al. (Nanofiltration Membrane with a Mussel-Inspired Interlayer for Improved Permeation Performance, 2017, hereinafter YANG).
Regarding Claim 16, modified YOON makes obvious a separation membrane of Claim 1. However, modified YOON does not explicitly disclose the separation membrane satisfying “0.28≤Aa/Ab≤0.50.”
YANG discloses that the prepared thin film composite nanofiltration membranes are characterized by ATR/IR and XPS, and show increased cross flow water permeation flux as compared with membranes without the mussel inspired interlayer (Abstract, Pg. 2318).
In the Experimental Section, the chemical structure of the PDA/PEI interlayer and the polyamide selective layer were evaluated by attenuated total reflectance Fourier transform infrared spectrometer FT-IR/ATR (Pg. 2319, Col. 2).
In the Results and Discussion, FT-IR/ATR spectra were used to demonstrate the chemical structures of the PSf substrates and the as prepared thin film composite nanofiltration membranes, and the peaks at 1570 cm⁻¹ and 1650 cm⁻¹ refer to N–H and C–N vibrations of the PDA/PEI interlayer, and the peaks at 1484 cm⁻¹ and 1700 cm⁻¹ are identified as O–C═O stretching vibrations of the polyamide layer (Pg. 2321, Col. 2 – Pg. 2322, Col. 1).
FT-IR/ATR characterization of the selective polyamide layer is a known, routine membrane characterization technique used to evaluate chemical structure and confirm formation of the polyamide layer, as YANG discloses evaluating the chemical structure of the polyamide selective layer by FT-IR/ATR (Pg. 2319, Col. 2; Pg. 2321, Col. 2 – Pg. 2322, Col. 1). In view of modified YOON’s separation membrane formed by interfacial polymerization, a person skilled in the art would apply YANG’s FT-IR/ATR characterization to the modified YOON membrane to evaluate the chemical structure of the polyamide selective layer as part of routine membrane characterization by identifying the FT-IR peaks.
Regarding the ratio range “0.28≤Aa/Ab≤0.50,” where Aa is the absorbance value at 1640 cm⁻¹ and Ab is the absorbance value at 1587 cm⁻¹ during FT-IR analysis, modified YOON forms an interfacially polymerized polyamide barrier layer on a porous support that is structurally and compositionally similar to the claimed separation membrane. It is reasonably interpreted that structurally and compositionally similar interfacially polymerized polyamide layers will exhibit the same FT-IR absorbance behavior, such that applying the FT-IR characterization method disclosed by YANG to modified YOON will yield an Aa/Ab ratio within the claimed range (In re Best, 562 F.2d 1252; 1977; In re Schreiber, 128 F.3d 1473; 1997).
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 apply FT-IR characterization, as disclosed by YANG, to the separation membrane by modified YOON.
Claims 17 and 18 are rejected under 35 U.S.C. 103 as being unpatentable over YOON and TOMASCHKE as applied to claim 1 above, and further in view of HU et al. (Enhancing the performance of aromatic polyamide reverse osmosis membrane by surface modification via covalent attachment of polyvinyl alcohol (PVA), 2016, hereinafter HU).
Regarding Claims 17 and 18, modified YOON makes obvious a separation membrane of Claim 1. However, modified YOON does not explicitly disclose “a protective layer on a surface of the separation membrane,” nor that “the protective layer comprises polyvinyl alcohol.”
HU discloses a method of modifying a commercial aromatic polyamide thin film composite reverse osmosis membrane through sequential surface treatment with glutaraldehyde aqueous solution followed by polyvinyl alcohol aqueous solution, where the polyvinyl alcohol molecules are covalently attached to the surface, thereby providing a membrane having a protective layer comprising polyvinyl alcohol on a surface of the membrane (Abstract, Pg. 209).
The sequential surface treatment with glutaraldehyde aqueous solution followed by polyvinyl alcohol aqueous solution is used to covalently attach polyvinyl alcohol molecules onto the surface of an aromatic polyamide thin film composite membrane, thereby forming a durable protective layer on the membrane surface (Introduction, Pg. 210, Col. 1).
In Membrane physico-chemical property, surface streaming potential measurements show the membrane becomes less negatively charged at neutral pH after modification, with the surface negative charge decreasing from 55.2 mV down to 30.5 mV as the polyvinyl alcohol content increases, and the reduced negative charge is attributed to shielding by covalently linked polyvinyl alcohol and hydrogen bonding between polyamide carboxylic groups and polyvinyl alcohol hydroxyl groups. The observed changes in morphology, hydrophilicity, and surface charge confirm covalent attachment of polyvinyl alcohol on the surface of the pristine polyamide thin film composite reverse osmosis membrane, and the physico-chemical properties are tunable by changing the polyvinyl alcohol content (§ 3.1, Pg. 214).
Advantageously, covalent attachment of polyvinyl alcohol on the membrane surface disclosed by HU forms a durable protective layer that improves resistance to fouling and chlorine while enhancing or maintaining membrane separation performance (Introduction, Pg. 210, Col. 1; Abstract, Pg. 209). In view of modified YOON’s separation membrane formed by interfacial polymerization, a person skilled in the art would incorporate HU’s covalently attached polyvinyl alcohol protective layer on the surface of the separation membrane to provide a durable protective surface layer.
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 a covalently attached polyvinyl alcohol protective layer on a surface of the separation membrane, as disclosed by HU, into the separation membrane by modified YOON.
Response to Arguments
Applicant’s arguments with respect to claims 1–4, 13, and 14 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to TAK L. CHIU whose telephone number is (703)756-1059. The examiner can normally be reached M-F: 9:00am - 6:00pm (CST).
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/TAK L. CHIU/Examiner, Art Unit 1777
/KRISHNAN S MENON/Primary Examiner, Art Unit 1777