DETAILED ACTION
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 .
Claim Rejections - 35 USC § 103
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.
Claims 1, 4, 5, 14, 19 and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Inui et al., JP 2020011215 A. Note that Inui et al., US 2021/0260516 A1 is cited as an English translation because it is in the same patent family as Inui et al., JP 2020011215 A.
Regarding claim 1, Inui teaches an air filter medium 3, which reads on the claimed “air filter medium.” See Inui Fig. 3, [0046].
The air filter medium 3 comprises a first fluororesin porous film 31, which reads on the “fluororesin porous membrane.” See Inui Fig. 3, [0046].
The air filter medium 3 also comprises an upstream air-permeable supporting member 21 stacked on an upstream side of the first fluororesin porous film 31, which reads on the claimed “supporting member stacked on at least one side of the fluororesin porous membrane.” See Inui Fig. 3, [0046].
The initial pressure loss of the air filter medium 3 ranges from 30 to 155 Pa, with pressure loss being measured when air is passed through the air filter medium at a flow velocity of 5.3 cm/s. See Inui [0033], [0041]. This pressure loss of 30 to 155 Pa describes the pressure loss of the first fluororesin porous film 31 because the pressure loss of the other two layers of the air filter medium (air-permeable supporting members 21, 22) is substantially zero. Id. [0105]. The prior art range of 30 to 155 Pa for the first fluororesin porous film 31 reads on the first fluororesin porous film 31 overlaps with “the fluororesin porous membrane has a pressure loss of 80 Pa or less when air is passed at a flow rate of 5.3 cm/s,” establishing a prima facie case of obviousness.
The first fluororesin porous film 31 has a PF value of 25.0 or more because the air filter medium 3 has a PF value of 25.0 or more with the first fluororesin porous film 31 being the only layer of the air filter medium 3 that contributes significantly to filtration (as the other layers 21, 22 are for support). See Inui [0039], [0105]. The prior art PF value of 25.0 or more overlaps with the claimed range of 20 or more. Note that the PF value of Inui is measured with the same formula as claimed, except that collection efficiency is determined using NaCl particles with a particle size of 0.3 µm instead of 0.1 µm as claimed. Id. at [0013]. But this slight difference fails to patentably distinguish Inui over the claim because the porous film 31 has substantially the same structure as the claimed “fluororesin porous membrane” while the Examiner has a sound basis for believing that the first fluororesin porous film 31 has an initial PF value that is within the claimed PF value of 20 or more, because the first fluororesin porous film 31 has an initial PF value of 25.0 or more measured with the same formula as claimed, except determined using slightly larger NaCl particles (0.3 µm vs. 0.1 µm). Therefore, the applicant has the burden of showing that the filter medium of Inui does not necessarily or inherently possess the claimed PF value, so as to either anticipate or render obvious claim 1. See MPEP 2112, subsection V (once a reference teaching a product appearing to be substantially identical is made as the basis of a rejection, and the examiner presents evidence or reasoning to show inherency, the burden of production shifts to the applicant).
The first fluororesin porous film 31 has a thickness of 30 µm or more. See Inui [0017]. The prior art range of 30 µm or more is within the claimed range of 10 µm or more and 36 µm or less, establishing a prima facie case of obviousness.
The air filter medium 3 has a dust holding capacity of 20.0 g/m2 or more when air containing polyalphaolefin (PAO) particles is continuous passed through the first fluororesin porous film at a flow rate of 5.3 cm/s and pressure loss increases by 250 Pa. See Inui [0014]. The prior art range of 20.0 g/m2 is within the claimed range of 15.0 g/m2 or more.
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Regarding claim 4, Inui teaches that the first fluororesin porous film 31 (the “fluororesin porous membrane”) contains a fibrillatable polytetrafluoroethylene (the “fibrillatable polytetrafluoroethylene”), a non-fibril-forming non-melting-processable component (the “non-fibrillatable non-melt-fabricable component”) and a non-fibril-forming hot-melt-processable component having a melting point lower than 320°C (the “non-fibrillatable melt-fabricable component having a melting point of lower than 320°C”). See Inui [0020].
Regarding claims 5 and 14, Inui teaches that the first fluororesin porous film 31 (the “fluororesin porous membrane”) contains a modified polytetrafluoroethylene. See Inui [0054], [0057].
Regarding claim 19, Inui teaches that the air filter medium has substantially the same structure as the air filter medium described in claim 19, as explained in the rejection of claim 1 above. The limitations of claim 19 describe the method of manufacturing the air filter medium, rather than its structure. These limitations fail to patentably distinguish the air filter medium of claim 19 over the air filter medium of Inui. See MPEP 2113, subsection I (the patentability of a product does not depend on its method of production unless the process steps imply structure).
Regarding claim 20, Inui teaches that the air filter medium comprises a shape including mountain folds (one being a “mountain fold portion”) and valley folds (one being a “valley fold portion”). See Inui [0125]. The air filter medium is presumed to exhibit the claimed properties of— “when air containing polyalphaolefin particles having a number median diameter of 0.25 um is continuously passed through the pleated mask filter medium at a flow rate of 85 L/min to apply a load of 200 mg of the polyalphaolefin particles, the pleated mask filter medium has a pressure loss of 120 Pa or less when air is passed at a flow rate of 40 L/min”—because the air filter medium of Inui has substantially the same structure as the claimed “air filter medium.” See MPEP 2112.01, subsection I (when the structure recited in the reference is substantially identical to that of the claims, claimed properties or functions are presumed to be inherent). With respect to the limitations describing that the air filter medium is produced by the method according to claim 6, the air filter medium has substantially the same structure as the air filter medium described in claim 20, as explained above. The limitations describing the process steps of making the air filter medium fail to patentably distinguish the air filter medium of claim 20 over the air filter medium of Inui because there is no evidence that the method steps of claim 20 result in a different structure than the filter medium of claim 20. See MPEP 2113, subsection I (the patentability of a product does not depend on its method of production unless the process steps imply structure).
Claims 3, 11 and 13 are rejected under 35 U.S.C. 103 as being unpatentable over Inui et al., JP 2020011215 A in view of Sawada et al., US 2013/0267621 A1. Note that Inui et al., US 2021/0260516 A1 is cited as an English translation because it is in the same patent family as Inui et al., JP 2020011215 A.
Regarding claim 3, Inui teaches the limitations of claim 1, as explained above.
Inui differs from claim 3 because it is silent as to the coefficient of variation of pressure loss of the air filter medium. Therefore, the reference fails to provide enough information to teach the air filter medium has a coefficient of variation of pressure loss of 6.0 or less. But Sawada teaches that the coefficient of variation of pressure loss of a fluororesin membrane of an air filter is result effective because it impacts the variation in pressure loss across the membrane, which impacts filtration performance. See Sawada [0060], [0070]. It would have been obvious to use routine experimentation to determine the optimal coefficient of variation of pressure loss of the air filter medium of Inui to optimize the variation in pressure loss across the membrane. See MPEP 2144.05, subsection II (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).
Regarding claim 11, Inui teaches that the first fluororesin porous film 31 (the “fluororesin porous membrane”) contains a fibrillatable polytetrafluoroethylene (the “fibrillatable polytetrafluoroethylene”), a non-fibril-forming non-melting-processable component (the “non-fibrillatable non-melt-fabricable component”) and a non-fibril-forming hot-melt-processable component having a melting point lower than 320°C (the “non-fibrillatable melt-fabricable component having a melting point of lower than 320°C”). See Inui [0020].
Regarding claim 13, Inui teaches that the first fluororesin porous film 31 (the “fluororesin porous membrane”) contains a modified polytetrafluoroethylene. See Inui [0054], [0057].
Claims 7 and 8 rejected under 35 U.S.C. 103 as being unpatentable over Inui et al., JP 2020011215 A in view of Uchiyama et al., US 2015/0013295 A1. Note that Inui et al., US 2021/0260516 A1 is cited as an English translation because it is in the same patent family as Inui et al., JP 2020011215 A.
Regarding claim 7, Inui teaches the limitations of claim 1, as explained above.
Inui differs from claim 7 because it is silent as to the air filter medium being a “mask filter medium,” as claimed.
But Inui teaches that the air filter medium can be used in various applications, such as ultra low penetration air filters for producing semiconductors (i.e., clean rooms) and filters for vacuum cleaners. See Inui [0119]. With this in mind, Uchiyama teaches a filter medium comprising a porous fluororesin membrane and an air-permeable support member, where the filter medium is used in various applications including a clean room, vacuum cleaner filter or mask. See Uchiyama [0059], [0079].
It would have been obvious to use the air filter medium of Inui in a mask because this is a suitable application for air filter media with a similar configuration as the air filter medium of Inui.
Regarding claim 8, Inui teaches the air filter medium can be pleated. See Inui [0125]. The air filter medium is presumed to exhibit the claimed properties of— “when air containing polyalphaolefin particles having a number median diameter of 0.25 um is continuously passed through the pleated mask filter medium at a flow rate of 85 L/min to apply a load of 200 mg of the polyalphaolefin particles, the pleated mask filter medium has a pressure loss of 120 Pa or less when air is passed at a flow rate of 40 L/min”—because the air filter medium of Inui has substantially the same structure as the claimed “air filter medium.” See MPEP 2112.01, subsection I (when the structure recited in the reference is substantially identical to that of the claims, claimed properties or functions are presumed to be inherent).
Inui differs from claim 8 because it is silent as to the air filter medium being a “mask filter medium,” as claimed.
But Inui teaches that the air filter medium can be used in various applications, such as ultra low penetration air filters for producing semiconductors (i.e., clean rooms) and filters for vacuum cleaners. See Inui [0119]. With this in mind, Uchiyama teaches a filter medium comprising a porous fluororesin membrane and an air-permeable support member, where the filter medium is used in various applications including a clean room, vacuum cleaner filter or mask. See Uchiyama [0059], [0079].
It would have been obvious to use the air filter medium of Inui in a mask because this is a suitable application for air filter media with a similar configuration as the air filter medium of Inui.
Response to Arguments
35 U.S.C. 112(d) Rejections
The Examiner withdraws the previous 35 U.S.C. 112(d) rejections.
35 U.S.C. 102 & 103 Rejections
The Applicant argues that the claim amendment of the fluororesin porous membrane having a thickness of 36 µm or less overcomes the previous 35 U.S.C. 102(a)(1) rejection over Example 4 of Inui, asserting that first fluororesin porous membrane in Example 4 has a thickness of 38.6 µm. See Applicant Rem. filed March 23, 2026 (“Applicant Rem.”) 7–8. The Examiner agrees and withdraws this rejection.
However, claim 1 is obvious over Inui because the broad disclosure of the reference teaches an air filter medium 3 with the same structure with ranges that are either within or overlap with the claimed ranges, as explained above.
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 T. BENNETT MCKENZIE whose telephone number is (571)270-5327. The examiner can normally be reached Mon-Thurs 7:30AM-6:00PM.
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T. BENNETT MCKENZIE
Primary Examiner
Art Unit 1776
/T. BENNETT MCKENZIE/Primary Examiner, Art Unit 1776
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