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 § 112(b)
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 1–7 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:
1. A filtration filter for filtering aerosols when the aerosols penetrate through from an upstream side to a downstream side, the filter comprising:
a plurality of module layers comprising at least four module layers, wherein each module layer of the plurality of module layers is an electrostatically-charged polyvinylidene fluoride (PVDF) nanofiber mat, wherein electrostatic charges are imparted to the PVDF nanofiber mat by corona discharge after formation of the PVDF nanofiber mat; and
a plurality of separators comprising at least three separators, wherein:
the electrostatically-charged PVDF nanofiber mat with charged nanofibers is configured to capture aerosols…Emphasis added.
Claim 1 is indefinite because it is unclear which of the “module layers, each…[being a] nanofiber mat” is referenced by “the electrostatically-charged PVDF nanofiber mat.”
To overcome this rejection, claim 1 could be amended to read:
1. A filtration filter for filtering aerosols when the aerosols penetrate through from an upstream side to a downstream side, the filter comprising:
a plurality of module layers comprising at least four module layers, wherein each module layer of the plurality of module layers is an electrostatically-charged polyvinylidene fluoride (PVDF) nanofiber mat, wherein electrostatic charges are imparted to the PVDF nanofiber mat by corona discharge after formation of the PVDF nanofiber mat; and
a plurality of separators comprising at least three separators, wherein:
[[the]] each electrostatically-charged PVDF nanofiber mat with charged nanofibers is configured to capture aerosols…
Claims 2–7 are indefinite because they depend from claim 1.
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 1–3 are rejected under 35 U.S.C. 103 as being unpatentable over Jaganathan et al., US 2018/0169551 A1 in view of Yegya-Raman et al., US 2021/0370208 A1 and as evidenced by Kuo et al., US 8,536,663 B1.
Regarding claim 1, Jaganathan teaches a filter media, which reads on the claimed “filtration filter.” See Jaganathan [0002]. The filter media is capable of filtering aerosols with the aerosols penetrating through an upstream side to a downstream side, as claimed. Id. at [0098], [0263]. An embodiment (Fig. 1E) illustrates the filter comprising main filter layers (second and fourth layers 120, 140) alternately stacked with three other layers that can be support layers (first, third and fifth layers 110, 130, 150) with a pre-filter layer on the upstream side. Id. at Fig. 1E, [0097], [0110]. While the reference is silent as to the filter media comprising two additional main filter layers, the reference teaches that the filter media can comprise additional main filter layers (as it describes two or more main filter layers, id. at [0164]) with the filter media comprising seven or more layers in a different order than illustrated in Fig. 1E (id. at [0110]). The reference also teaches that the filter media can comprise additional main filter layers (as it describes two or more main filter layers, id. at [0164]). It would have been obvious to provide an additional main filter layer on the top and bottom of the filter media with a support layer covering each additional main filter layer, and with a pre-filter on the upstream side because the reference suggests that this configuration, with adding additional layers merely representing obvious duplication of parts.
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With this modification, Jaganathan is mapped as follows:
The pre-filter layer and the three main filter layers read on the “plurality of module layers comprising at least four module layers.”
The pre-filter layer and each of the main filter layers can be manufactured from polyvinylidene fluoride (PVDF) nanofibers and with the pre-filter and each main filter layer being electrostatically charged. See Jaganathan [0129]–[0130], [0166]–[00167], [0229]. This reads on “each module layer of the plurality of module layers is an electrostatically-charged polyvinylidene fluoride (PVDF) nanofiber mat.” The limitation of “electrostatic charges are imparted to the PVDF nanofiber mat by corona discharge after formation of the PVDF nanofiber mat” fails to patentably distinguish over the prior art because it describes the process of manufacturing the nanofiber mat, with there being no evidence that the manufacturing steps impart distinctive structure over the prior art. See MPEP 2113, subsection I.
The support layers read on the “plurality of separators comprising at least three separators.”
The filter media also has the following:
The pre-filter layer and each main filter layer is capable of capturing aerosols, as claimed. See Jaganathan [0098].
The pre-filter layer, main filter layers, and separator layers are planar and alternately stacked and connected together, as claimed. See Jaganathan Fig. 1E, [0110].
Each support layer has adhesion with the pre-filter layer and main filter layers, as claimed. See Jaganathan [0211].
Each support layer comprises pores having a mean flow pore size of 20 to 300 microns. See Jaganathan [0202]. This reads on “additional macropores for each separator.” The pores are capable of re-orienting an airflow of the aerosols through the pre-filter layer and the main filter layers from the upstream side to the downstream side, as claimed, because the aerosol is capable of changing direction (i.e., being reoriented) when it flows through the pores of each support layer. See MPEP 2114 (functional claim language that is not limited to a specific structure covers all devices that are capable of preforming the recited function).
The pre-filter layer and each main filter layer has charged nano-fibers, as claimed. See Jaganathan [0129], [0167], [0229].
The fibers of the pre-filter layer have a diameter of 0.5 to 1.0 micron (500 to 1,000 nm) and the fibers of each main filter layer have a diameter of 40 to 500 nm. See Jaganathan [0129], [0167]. Also, the pre-filter layer has a basis weight of 0.5 to 100 g/m2 (gsm), while each main filter layer has a basis weight of 0.001 to 50 gsm. Id. at [0154], [0174].
These ranges overlap with “(i) each of the charged nanofibers has a fiber diameter in a range between 350nm to 650nm and said each module layer…has a fiber basis weight in a range between 0.4gsm to 0.99gsm,” establishing a prima facie case of obviousness.
Also, the pre-filter layer and each main filter layer is capable of performing the function of capturing aerosols by the charged nanofibers of each layer with the aerosols being distributed uniformly across an entire width of the filter media from the upstream side to the downstream side, because the structure of the pre-filter layer and each main filter layer is substantially the same as the claimed “each module layer.” 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).
The filter media is also presumed to be capable of trapping up to 70% of the aerosols inside the filter during depth filtration and only about 30% of the aerosols to form a cake during cake filtration because Jaganathan teaches that the filter media can have a particulate efficiency of 35 to 90%, and is tested with 0.3 micron DOP aerosol particles with the particles penetrating across the filter media (i.e., depth filtration). See Jaganathan [0245], [0249]. Note also that the limitation of “the filter is configured to trap up to 70% of the aerosols inside the filter during depth filtration and only about 30% of the aerosols form a cake layer during cake filtration” fails to patentably distinguish over the prior art because it describes the function rather than the structure of the claimed apparatus. See MPEP 2114 (manner of operating the device does not differentiate apparatus claim from the prior art).
Jaganathan differs from claim 1 because it is silent as to each support layer (“each separator”) being configured to be antistatic while also being configured to provide insulation between module layers for reducing electrical interference from the charged nanofibers of the pre-filter layer and each main filter layer, as claimed.
But Jaganathan teaches that each support layer can be made from various materials, meltblown, meltspun, electrospun, or centrifugal spun fibers. See Jaganathan [0184].
With this in mind, Yegya-Raman teaches a filter media comprising at least one charged fiber layer that is supported by at least one support layer. See Yegya-Raman [0047], [0064]. The support layer can be made from various materials including non-woven webs (made from meltblown, spunbond or electrospun fiber webs) or a metal mesh. See Yegya-Raman [0064].
It would have been obvious for each support layer of Jaganathan to be manufactured from a metal mesh because this would merely represent the selection of a known material based on the suitability of its intended use. See MPEP 2144.07.
With this modification, each support layer of Jaganathan (“each separator”) is configured to be anti-static, as claimed, because metal is conductive and therefore is anti-static. Also, because each support layer is positioned between the pre-filter layer and the main filter layers (the “module layers”) with each support layer being a metal mesh, each support layer is capable of providing insulation between module layers for reducing electrical interference from the charged nanofibers of the pre-filter layer and main filter layers, as claimed. See e.g., Kuo abstract (metal mesh cap serves as a particulate filter and a conductive shield for EMI/RF interferences).
Regarding claim 2, Jaganathan teaches that the pre-filter layer has an efficiency ranging from 20 to 99.5% and a quality factor ranging from 0.000455 to 5.4/Pa. See Jaganathan [0157], [0160]. Also, each main filter layer has an efficiency ranging from greater than 20 to 99.5% (as they each have a higher efficiency than the other layers of the filter media, id. at [0100]) and a quality factor of 0.000306 to 1.081/Pa. Id. at [0100], [0175]. The prior art ranges of 20 to 99.5% and 0.000455 to 5.4/Pa and 0.000306 to 1.081/Pa overlap with the claimed ranges of greater than 50% and greater than 0.1/Pa, establishing a prima facie case of obviousness. See MPEP 2144.05, subsection I. Note that quality factor is calculated using the formula:
Q
=
-
l
n
(
1
-
n
)
Δ
p
where
n
is efficiency (represented as a decimal) and
Δ
p
is pressure drop (measured in pascals). See Spec. [0070], [0014].
Regarding claim 3, the limitations of this claim—‘the fiber basis weight for a particular fiber diameter is selected to achieve the efficiency of greater than 50% and the quality factor of greater than 0.1/Pa’—fails to further limit the scope of the claim because it describes the process of manufacturing the filter (i.e., making a selection in the fabrication process) instead of the structure of the filter itself. See MPEP 2113, subsection I (the patentability of a product does not depend on its method of production).
Claims 4–7 are rejected under 35 U.S.C. 103 as being unpatentable over Jaganathan et al., US 2018/0169551 A1 in view of Yegya-Raman et al., US 2021/0370208 A1 in further view of Ramakrishna et al., US 2010/0113857 A1 and as evidenced by Kuo et al., US 8,536,663 B1.
Regarding claim 4, Jaganathan teaches that the charged nanofibers of the pre-filter layer and each main filter layer can comprise an antimicrobial additive. See Jaganathan [0199].
Jaganathan differs from claim 4 because it is silent as to the charged nanofibers having the antimicrobial additive integrated into it.
But Jaganathan teaches that the charged nanofibers can be electrospun. See Jaganathan [0128], [0165].
With this in mind, Ramakrishna teaches a filter material comprising nano-sized or micro-sized fibers manufactured using an electrospinning process comprising detoxifying particles integrated into the fibers. See Ramakrishna [0011], [0015]. The detoxifying particles are “antimicrobials” because they are used to decontaminate toxic agents including biological warfare agents. Id. at [0014].
It would have been obvious for the antimicrobial additive to be the detoxifying particles of Ramakrishna, integrated into the fibers of the pre-filter layer and each main filter layer to allow the filter media of Jaganathan to be able to decontaminate toxic agents including biological warfare agents, with the procedure of Ramakrishna for incorporating the detoxifying particles into the electrospun fibers being a known technique for introducing antimicrobial additives into a filter material.
Regarding claim 5, Ramakrishna teaches that the detoxifying particles are naturally occurring metal oxide particles, such as ZnO, oxides of copper, TiO2, SnO2, Al2O3, Fe3O4, which are chemical disinfection agents. See Ramakrishna [0046]–[0047].
Regarding claim 6, Ramakrishna teaches that the detoxifying particles can be one or more of the following of ZnO, TiO2, SnO2, Al2O3, Fe3O4, or mixtures. See Ramakrishna [0046].
Regarding claim 7, Jaganathan teaches that the nanofibers of the pre-filter layer have an average diameter of 0.5 to 1.0 µm (500 to 1,000 nm) while the nanofibers of each main filter layer have an average diameter of 40 to 500 nm. See Jaganathan [0129], [0167]. Also, Ramakrishna teaches that the detoxifying particles have an average particle size between 10 to 200 nm. See Ramakrishna [0043]. Therefore, the prior art teaches that the antimicrobials are in a form of nanoparticles with a size in a range from 0.01 to 5 times of an average diameter of the charged nanofibers. The prior art range of 0.01 to 5 overlaps with the claimed range of 0.1 to 1 time, establishing a prima facie case of obviousness.
Response to Arguments
35 U.S.C. 112(b) Rejections
The Examiner withdraws the previous 35 U.S.C. 112(b) rejections in light of the amendments.
35 U.S.C. 102 & 103 Rejections
Applicant’s arguments with respect to claims 1–7 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.
For the limitation—“each of the plurality of separators comprises additional macro-pores for the separator to re-orient an airflow of aerosols through the plurality of module layers from the upstream side to the downstream side”—the Applicant notes that Jaganathan teaches layers that have pores with a mean flow pore size. See Applicant Rem. filed May 28, 2026 (“Applicant Rem.”) 6. But it is argued that the reference never uses the term “additional macro-pores” while asserting that the reference fails to describe any pores as being configured “for the separator to re-orient airflow.” Id.
The Examiner respectfully disagrees. The “additional macro-pores” are the only pores of each separator in claim 1. Each support layer of Jaganathan has pores which are “macro-pores” because they a mean flow pore size of 20 to 300 microns. See Jaganathan [0202]. The pores are capable of performing the function of re-orienting an airflow of the aerosols through the pre-filter layer and main filter layers (“each module layer”) from the upstream side to the downstream side, as claimed, because air could change direction (i.e., be reoriented) when it flows through the pores.
For the limitation—“electrostatic charges are imparted to the PVDF nanofiber mat by corona discharge after formation of the PVDF nanofiber mat”—the Applicant argues that this limitation distinguishes over Jaganathan asserting that there is no mention of the fibers being electrostatically charged by an additional corona discharge process so that the electrostatic charges can stay almost permanently with the fibers. See Applicant Rem. 11–12.
The Examiner respectfully disagrees because Jaganathan teaches that the fibers can be electrostatically charged using techniques, such as corona charging. See Jaganathan [0161], [0229], [0336].
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Smithies et al., US 2021/0121804 A1 (Fig. 2 illustrating a filter media comprising an electrostatically charged pre-filter layer 14 supported by a metal mesh support layer 20).
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
