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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 December 12, 2025 has been entered.
Priority
Acknowledgment is made of applicant’s claim for foreign priority (JP2020-089970, filed on 22 May 2020) 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 “an area of at least 623.7 cm² and in a region of 623.7 cm² or more of an area of the porous membrane” should be corrected to read “an area of at least 623.7 cm²; and wherein, in a region of the porous membrane having an area of 623.7 cm² or more,” for clarity.
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 and 4 are rejected under 35 U.S.C. 103 as being unpatentable over HAYASHI et al. (US20150079392A1, hereinafter HAYASHI) in view of ZYDNEY et al. (Effect of Membrane Morphology on System Capacity During Normal Flow Microfiltration, 2003, hereinafter ZYDNEY) and JERMAN et al. (US20120234745A1, hereinafter JERMAN).
Regarding Claim 1 and 4, HAYASHI discloses a fluororesin microporous membrane having through-pores with very small pore sizes, formed by baking fluororesin particles containing PTFE as a main component to make a membrane substantially nonporous and stretching the membrane to make it porous, and the membrane is used as a filtration membrane (filter) for filtering fine particles (¶¶[0002]-[0003]).
In particular, in forming the fluororesin microporous membrane, annealing increases repeatability of pore size before stretching. The stretching may be either uniaxial stretching or biaxial stretching, where pores are formed in the fluororesin nonporous membrane by stretching and the magnitude of stretching is controlled to obtain a desired mean flow pore size. The resulting fluororesin microporous membrane has a narrow pore-size distribution and a small difference between mean flow pore size and maximum pore size (¶¶[0027]-[0029]).
The porous resin-membrane composite is formed by bonding the fluororesin nonporous membrane to the PTFE porous support to form the composite and then stretching the composite so that the nonporous membrane becomes the fluororesin microporous membrane (¶¶[0069]-[0072]).
The mean flow pore size and maximum pore size are measured by a bubble point method (ASTM F316-86, JIS K3832) using a pore-size distribution measuring device with the membrane wet with GALWICK, where the membrane is fully wetted and a minimum pressure P at which gas permeation starts is measured, and the mean flow pore size and maximum pore size are calculated as d=cγ/P (¶¶[0079]-[0080]).
In Example 1, the mean flow pore size was measured at 35 nm and the maximum pore size at 48 nm (¶[0089]). In Example 2, the mean flow pore size was measured at 29 nm and the maximum pore size at 34 nm (¶[0096]). The collection-layer thickness was 1.6 μm in both cases (¶[0089]; ¶[0096]). The disclosed mean pore sizes fall within the claimed “mean pore size of 25 nm to 35 nm,” the disclosed maximum pore sizes fall within the claimed “maximum pore size of 49 nm or less,” and the disclosed collection-layer thickness reads upon the claimed “average thickness of 0.6 μm to 3.5 μm.”
However, HAYASHI does not explicitly disclose the porous membrane having an area of at least 623.7 cm².
ZYDNEY discloses that large-scale filtration systems use flat-sheet membranes or fiber mats packaged as membrane disk stacks and cartridges available in standard sizes such as 10, 20, 30, and 40 inches, and that in the flow decay method filter capacity is evaluated using a small area test filter and extrapolated to larger scale by assuming capacity scales linearly with membrane area, where optimal area is a function of the specific filter combination used in the process (Introduction, Pg. 537).
The scale-up framework disclosed by ZYDNEY can be used to predict system capacity based on relatively limited experimental data, allowing for more rapid and less expensive design and scale-up of microfiltration systems (Conclusions, Pg. 543). In view of HAYASHI’s porous membrane laminate, a person skilled in the art would employ the scale-up framework to determine, based on system capacity targets, the membrane area needed and to size the porous membrane to have an area of at least 623.7 cm² through routine optimization using membrane-area scale-up 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 employ the scale-up framework, as disclosed by ZYDNEY, to scale the membrane area of the porous membrane laminate by HAYASHI.
However, modified HAYASHI does not explicitly disclose “the porous membrane laminate having an isopropanol bubble point from 600 kPa to 1310 kPa.”
JERMAN discloses determining the bubble point of a fiber using isopropyl alcohol, where the fiber is wetted in isopropyl alcohol and pressurized to ensure there is no trapped air in the pores, the fiber is then looped and immersed in a container of isopropyl alcohol with the lumen ends above the level of the isopropyl alcohol, and air pressure is applied in small increments until the first bubble of air is observed, where the resulting pressure is the bubble point pressure and indicates the largest pore (¶¶[0088]-[0089]).
The isopropanol bubble point method disclosed by JERMAN is a well-known technique for characterizing porous membranes by determining a bubble point pressure as an indication of the largest pore. In view of modified HAYASHI’s porous membrane laminate, a person skilled in the art would perform an isopropanol bubble point test as a routine integrity/quality-control characterization at elevated pressures with predictable results.
Regarding the limitation “the porous membrane laminate has an isopropanol bubble point from 600 kPa to 1310 kPa,” this reflects a performance attribute governed by structural factors including material composition, pore size, membrane thickness, and porosity. HAYASHI discloses a porous PTFE membrane exhibiting the same material and structural parameters. Therefore, the claimed isopropanol bubble point would have been an expected result of that structure, including an isopropanol bubble point from 600 kPa to 1310 kPa. Absent persuasive evidence that the recited range is critical or yields an unexpected distinction, the limitation does not patentably distinguish over the prior art (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 perform an isopropanol bubble point test, as disclosed by JERMAN, on the porous membrane laminate by modified HAYASHI.
Response to Arguments
Applicant’s arguments, see Remarks filed December 12, 2025, with respect to the rejection of claims 1, 2, and 4 under 35 U.S.C. § 103 have been fully considered. Claim 1 has been amended, claim 2 has been cancelled, and claim 4 remains as previously presented. Accordingly, the prior rejection based on HAYASHI is withdrawn in view of the claim amendments. However, upon further consideration, a new ground of rejection is made under 35 U.S.C. § 103 in view of HAYASHI, ZYDNEY, and JERMAN.
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).
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/TAK L. CHIU/Examiner, Art Unit 1777
/KRISHNAN S MENON/Primary Examiner, Art Unit 1777