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 (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 Rejections - 35 USC § 112
Claims 1 and 4 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 1 recites “wherein a heat of fusion of polytetrafluoroethylene, which is the main component of the porous membrane, is from 25 J/g to 29 J/g.” The Specification states that the heat of fusion of PTFE in porous membrane 2 is preferably within this range (¶[0024]). However, it does not identify whether the value is measured from the starting PTFE material, the nonporous membrane, or the final stretched porous membrane, or specify the measurement conditions used to determine the value. Accordingly, it is unclear what material and measurement procedure define the recited range. Claim 4, which depends from Claim 1, is similarly rejected by virtue of dependency.
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 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).
Regarding Claims 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 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 fluororesin microporous membrane is bonded to a porous support and used as a porous resin-membrane composite, and a filter element includes the fluororesin microporous membrane as a filtration membrane (¶[0042]).
The heat of fusion of the fluororesin particles as a whole is preferably from 17 J/g to 60 J/g, more preferably from 20 J/g to 50 J/g, and still more preferably from 23 J/g to 45 J/g (¶[0054]). The disclosed ranges overlap the claimed “heat of fusion of polytetrafluoroethylene…is from 25 J/g to 29 J/g.”
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 and are calculated as
d
=
c
γ
P
, where c is 2,860 and γ is the surface tension of the liquid. For the maximum pore size, the membrane is fully wetted and a minimum pressure P at which gas permeation starts is measured (¶¶[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.”
Using the disclosed equation
d
=
c
γ
P
and an isopropanol surface tension of
21.7
d
y
n
c
m
, the isopropanol bubble-point pressure corresponding to the maximum pore size of 48 nm in Example 1 is calculated as
P
=
2,860
×
21.7
0.048
=
1,292,958
P
a
, or approximately 1,293 kPa, which reads upon the claimed “isopropanol bubble point from 600 kPa to 1310 kPa.”
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 apply the scale-up framework to determine the membrane area needed based on system-capacity targets and predictably obtain a porous membrane laminate having an area of at least 623.7 cm².
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.
Response to Arguments
Applicant’s arguments, see Remarks filed May 21, 2026, with respect to the rejection under 35 U.S.C. § 103 have been fully considered. Claim 1 has been amended. Accordingly, the prior rejection is withdrawn in view of the claim amendment. However, upon further consideration, a new ground of rejection is made under 35 U.S.C. § 103 in view of HAYASHI and ZYDNEY.
Although the prior rejection has been withdrawn in view of the claim amendment, certain arguments remain relevant to the present rejection and are addressed below.
Applicant argues that the claimed product is distinguished by the disclosed solvent-selection and pressure-resistance steps. However, Claim 1 does not recite these process steps, and Applicant has not shown that the unclaimed steps impart a structural distinction to the claimed porous membrane laminate.
Applicant argues that the area of at least 623.7 cm² is critical and that the cited references do not provide a reasonable expectation of maintaining the claimed pore properties over that area. However, Applicant has not provided comparative evidence establishing criticality at 623.7 cm², and ZYDNEY discloses scaling membrane area based on system-capacity requirements.
Applicant argues that HAYASHI measures bubble point using GALWICK rather than isopropanol. However, the present rejection does not equate the GALWICK pressure with an isopropanol pressure. The isopropanol bubble-point pressure is calculated from HAYASHI’s disclosed maximum pore size using the disclosed equation and the surface tension of isopropanol.
Applicant argues that HAYASHI’s example heat-of-fusion values fall outside the claimed range. However, HAYASHI separately discloses broader heat-of-fusion ranges that overlap the claimed range (¶[0054]). The uncertainty concerning the material and measurement procedure used to determine the claimed heat of fusion is addressed separately under 35 U.S.C. § 112(b).
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 1771
/KRISHNAN S MENON/Primary Examiner, Art Unit 1771
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