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 1–11 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, wherein each module layer of the plurality of module layers is an electrostatically-charged polyvinylidene fluoride (PVDF) nanofiber mat; and
a plurality of separators,
wherein:
the electrostatically-charged PVDF nanofiber mat with charged nanofibers is configured to capture aerosols;
the plurality of module layers and the plurality of separators are planar and alternatingly stacked and connected to one another; and
said each module layer of the plurality of module layers has a fiber basis weight depending on fiber diameter, thereby said each module layer of the plurality of module layers is configured such that the aerosols are capable of being captured by the charged nanofibers and distributed uniformly across an entire width of the filter from the upstream side to the downstream side,
wherein 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. Emphasis added.
Claim 1 is indefinite because the limitation describing each individual having “a fiber basis weight depending on fiber diameter” defines the basis weight in relation to fiber diameter, with fiber diameter being variable (as the fibers could have various sizes). See MPEP 2173.05(b), subsection II (reference to an object that is variable may render a claim indefinite). The relationship between basis weight and fiber diameter is not sufficiently defined, as the relationship is not based on any known standard, with the claim (and the specification) failing to specify how the basis weight depends on fiber diameter. It is noted that the Applicant argues that the basis weight is chosen based on the fiber diameter to enable each layer to perform the functions after the “thereby” clause in claim 1. See Applicant Rem. filed October 30, 2025 (“Applicant Rem.”) 6. But the Applicant fails to explain what the relationship between basis weight and diameter is, other than achieving the claimed functional result. Therefore, the limitation renders the claim indefinite because a person of ordinary skill in the art would not understand how the fiber basis weight depends on fiber diameter, as fiber diameter is variable and the relationship between basis weight and diameter is not defined (and is not based on a known standard).
Claims 2–11 are indefinite because they depend from claim 1.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claims 1 and 8 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Jaganathan et al., US 2018/0169551 A1.
Regarding claim 1, Jaganathan teaches a filter media 104, which reads on the claimed “filtration filter.” See Jaganathan Fig. 1E, [0001], [0110]. The filter media is capable of filtering aerosols with the aerosols penetrating through an upstream side to a downstream side. Id. at [0098], [0263].
The filter media 104 comprises a first layer 110 and a third layer 130, which reads on the “plurality of module layers.” See Jaganathan [0110]. The first and third layers 110, 130 can each be pre-filter layers, with the pre-filter layers each comprising electrostatically charged fibers made from PVDF. Id. at [0129]–[0130], [0161]. The fibers of each pre-filter layer are nanofibers1 because the fibers can have a diameter of 0.5 to 1.0 micron. Id. at [0129]. This reads on “each module layer of the plurality of module layers is an electrostatically-charged polyvinylidene fluoride (PVDF) nanofiber mat.”
The filter media 104 also comprises a second layer 120 and a fourth layer 140, which read on the “plurality of separators.” See Jaganathan Fig. 1E, [0110].
The first and third layers 110, 130 (each being an “electrostatically-charged PVDF nanofiber mat with charged nanofibers”) is capable of capturing aerosols because the filter media 104 is capable of capturing aerosols, with the first and third layers 110, 130 having the same structural characteristics as the claimed “electrostatically-charged PVDF nanofiber mat.” Id. at [0098], [0263].
The first and third layers 110, 130 are planar and alternately stacked and connected to one another, as seen in Fig. 1E.
Each of the first and third layers 110, 130 has a “fiber basis weight depending on fiber diameter” because each layer 110, 130 has a basis weight and is made of fibers each having a diameter. Note also that this limitation describes the process of making the claimed product because the “fiber basis weight depending on fiber diameter” describes the process of selecting the basis weight based on the fiber diameter to enable the function of uniform capture and distribution during filter design (after the “thereby” clause), as acknowledged by the Applicant. See Applicant Rem. 62. The patentability of a product does not depend on its method of production, unless the process implies structure. See MPEP 2113, subsection I. Here, there is no evidence that the process of choosing the basis weight based on fiber diameter imparts distinct structure from the prior art. Therefore, the “depending on” limitation fails to patentability distinguish over the prior art because it describes the process of making the claimed product rather than its structure.
The first and third layers 110, 130 are each capable of performing the function of capturing aerosols by the charged nanofibers of each layer 110, 130 with the aerosols being distributed uniformly across an entire width of the filter media 104 from the upstream side to the downstream side, because the structure of each layer 110, 130 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 104 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 the filter 104 has substantially the same structure as the claimed “filter.” See MPEP 2112.01, subsection I. Note also that Jaganathan expressly teaches that the filter 104 is capable of performing at least the limitation of trapping up to 70% of aerosols inside the filter during depth filtration, because the filter 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].
Regarding claim 8, Jaganathan teaches that the second and fourth layers 120, 140 (either being “an individual separator”) comprises pores having a size ranging from 0.1 to 50 microns, which are interpreted as “macro-pores3.” See Jaganathan [0180]. With respect to the limitation—“for the separator to re-orient an airflow of the aerosols through the plurality of module layers from the upstream side to the downstream side”—the pores of the second and fourth layers 120, 140 of Jaganathan are presumed to be capable of performing this function because they have the same structure as claimed. See MPEP 2112.01, subsection I.
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 2, 3, 10 and 11 are rejected under 35 U.S.C. 103 as being unpatentable over Jaganathan et al., US 2018/0169551 A1.
Regarding claim 2, Jaganathan teaches that each of the first and third layers 110, 130 (either one being the “individual module 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]. The prior art ranges of 20 to 99.5% and 0.000455 to 5.4/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).
Regarding claim 10, Jaganathan teaches that the fibers of the first and third layers 110, 130 (“each of the charged nanofibers”) has a fiber diameter ranging from 0.5 to 1.0 micron, which converts to 500 to 1,000 nm, and a basis weight of 0.2 to 40 g/m2 (gsm). See Jaganathan [0129], [0154]. The prior art range of 500 to 1,000 nm overlaps with the claimed range of 350 to 650 nm, and the prior art range of 0.2 to 40 gsm overlaps with the claimed range of 0.4 to 0.99 gsm, establishing a prima facie case of obviousness. Further, each of the first and third layers 110, 130 (either one being the “individual module layer”) has an efficiency ranging from 20 to 99.5% and a quality factor ranging from 0.000455 to 5.4/Pa. Id. [0157], [0160]. The prior art ranges of 20 to 99.5% and 0.000455 to 5.4/Pa overlap with the claimed ranges of greater than 90% and greater than 0.1/Pa, establishing a prima facie case of obviousness.
Regarding claim 11, Jaganathan teaches that the average fiber diameter of the first and third layers 110, 130 (“each of the charged nanofibers”) can be as small as 0.1 microns (100 nm), which is within the claimed range of “each of the charged nanofibers has a fiber diameter in a range between 50 and 350 nm. See Jaganathan [0125]. Further, the first and third layers 110, 130 have basis weight of 0.2 to 40 g/m2 (gsm). Id. at [0129], [0154]. The prior art range of 0.2 to 40 gsm overlaps with the claimed range of 0.2 to 0.3 gsm, establishing a prima facie case of obviousness. Further, each of the first and third layers 110, 130 (either one being the “individual module layer”) has an efficiency ranging from 20 to 99.5% and a quality factor ranging from 0.000455 to 5.4/Pa. Id. [0157], [0160]. The prior art ranges of 20 to 99.5% and 0.000455 to 5.4/Pa overlap with the claimed ranges of greater than 90% and greater than 0.1/Pa, establishing a prima facie case of obviousness.
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 Ramakrishna et al., US 2010/0113857 A1.
Regarding claim 4, Jaganathan teaches that the first and third layers 110, 130 can comprise an antimicrobial additive. See Jaganathan [0199].
Jaganathan differs from claim 4 because it is silent as to the charged nanofibers of either of the first or third layers 110, 130 having the antimicrobial additive integrated into it.
But Jaganathan teaches that the fibers of the first and third layers 110, 130 can be electrospun. See Jaganathan [0128].
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 of the first and third layers 110, 130 to be the detoxifying particles of Ramakrishna, integrated into the fibers of the first and third layers 110, 130 to allow the filter media 104 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 first and third layers 110, 130 have an average diameter of 0.5 to 1.0 µm, which converts to 500 to 1,000 nm. See Jaganathan [0129]. 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 0.4 times of an average diameter of the charged nanofibers. The prior art range of 0.01 to 0.4 overlaps with the claimed range of 0.1 to 1 time, establishing a prima facie case of obviousness.
Claim 9 is rejected under 35 U.S.C. 103 as being unpatentable over Jaganathan et al., US 2018/0169551 A1 in view of Midkiff, US 6,322,604 B1.
Regarding claim 9, Jaganathan teaches that the second layer 120 (an “individual separator”) has adhesion to the first and third layers 110, 130. See Jaganathan Fig. 1E, [0211].
Jaganathan differs from claim 9 because it is silent as to the second layer 120 being anti-static. But the reference is silent as to the second layer 120 being necessarily electrostatically charged. Also, the second layer 120 can include various additives. See Jaganathan [0169]. Further, Midkiff teaches that anti-static additives can be applied to filter material to impart improved characteristics. See Midkiff col. 7, ll. 31–42. It would have been obvious for the second layer 120 to be treated with anti-static additives to impart improved characteristics to the second layer 120.
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. The claims remain indefinite, however, for the reasons stated above.
35 U.S.C. 102(a)(1) & 103 Rejections
The Applicant argues that Jaganathan fails to teach each module layer has a “fiber basis weight depending on fiber diameter” thereby each layer is “configured such that aerosols are capable of being captured by the charged nanofibers and distributed uniformly across an entire width of the filter from the upstream side to the downstream side.” See Applicant Rem. 6. Instead, it is argued that it is known in the art that fiber basis weight is not dependent on fiber diameter along, but on various factors during electrospinning and design. Id. The Applicant argues that the claim language specifically requires a relationship between the fiber basis weight and the fiber diameter, wherein the basis weight depends on the fiber diameter to the extent necessary to achieve the defined results. The Applicant also states: “i.e., the basis weight is chosen based on the fiber diameter to enable the subsequent ‘thereby’ clause for uniform capture and distribution.” Id. (emphasis added). The Applicant also argues that there is no discussion in Jaganathan of “selecting” fiber basis weight “depending on” fiber diameter for uniform aerosol distribution across an entire width of the filter from the upstream to downstream side. Id. (emphasis added).
The Examiner respectfully disagrees. The “depending on” limitation describes a process step in manufacturing the claimed “filtration filter” (a product), because this limitation describes part of the filter design in selecting the fiber basis weight depending on the fiber diameter to achieve the claimed functional properties of uniform capture and distribution. The Applicant acknowledges that the “depending on” limitation is a process limitation by indicating that the basis weight is “chosen” based on the fiber diameter, with the difference between Jaganathan and claim 1 being that there is no discussion in the prior art of “selecting” fiber basis weight depending on fiber diameter. See Applicant Rem. 6 (emphasis added). The “patentability of a product does not depend on its method of production” unless the process steps imply structure. See MPE 2113, subsection I. Also, the Applicant bears the burden of establishing a nonobvious difference between a claimed product and the prior art when the examiner provides a rationale to show that the claimed product is the same or similar to the prior art. See MPEP 2113, subsection II. Here, the Examiner has provided evidence that the filter media of Jaganathan has all of the structural characteristics as the claimed “filtration filter” as explained in the 102 rejection of claim 1 above. Even if Jaganathan is silent as to the basis weight of the first and third layers 110, 130 (“each module layer”) being selected “depending on fiber diameter” there is no evidence that this difference in the manufacturing process results in structural difference between the claimed “filtration filter” and the filter media of Jaganathan, and the Applicant has provided no evidence of a structural difference between the claimed product and the prior art. Therefore, the limitation of each module layer has “a fiber basis weight depending on fiber diameter” fails to patentably distinguish over the prior art, because it describes the process of making the claimed product, with there being no evidence that the process limitation results in a different structure than the filter media taught in Jaganathan.
The Applicant also argues that each layer 110, 130 of Jaganathan is not inherently capable of performing the claimed function of capturing aerosols by the charged nanofibers of each layer 110, 130 with the aerosols being distributed uniformly across an entire width of the filter media from the upstream to downstream side. See Applicant Rem. 6–7. The Examiner maintains that each layer 110, 130 of Jaganathan is presumed to be inherently capable of performing these functions because each layer 110, 130 is structurally identical to the claimed “each module layer.” Note that the Applicant has the burden of showing that product of Jaganathan is not the same as the claimed “filtration filter.” See MPEP 2112.01, subsection I.
The Applicant further argues that Jaganathan fails to teach the functional limitations of:
“wherein 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.”
The Applicant argues that the filter media of Jaganathan is not inherently capable of performing these claimed functions, asserting that the filter media of Jaganathan is structurally different than the claimed filtration filter. See Applicant Rem. 7. The Applicant also argues that the functional limitations quoted above imply structural limitations on the claimed filtration filter, which the Applicant asserts are not taught in Jaganathan. Id.
The Examiner respectfully disagrees. When the structure recited in the reference is substantially identical to that of the claims, claimed properties or functions are presumed to be inherent. See MPEP 2112.01, subsection I. Also, when the PTO has a sound basis for believing that the products of the applicant and the prior art are the same, the applicant has the burden of showing that they are not. Here, the limitations quoted above describe the function rather than the structure of the claimed “filtration filter” because the limitations describe what the filter is capable of doing—“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.” There is no evidence that there is a structural difference between the filter media of Jaganathan and the claimed “filtration filter” because the only alleged differences involve the process of making the claimed product (selecting “fiber basis weight depending on fiber diameter”) and the functional properties of the claimed product (uniform capture and distribution, trapping up to 70% of aerosols during depth filtration and only 30% of aerosols forming a cake during cake filtration). The Applicant has also failed to provide any evidence of a structural difference between the filter media of Jaganathan and the claimed filtration filter. Therefore, because the filter media of Jaganathan has the same structure as the claimed filtration filter, the filter media of Jaganathan is presumed to be capable of performing the claimed functions.
Conclusion
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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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Jennifer Dieterle can be reached at 571-270-7872. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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T. BENNETT MCKENZIE
Primary Examiner
Art Unit 1776
/T. BENNETT MCKENZIE/Primary Examiner, Art Unit 1776
1 The Applicant’s disclosure defines nanofibers as fibers having a median size of less than 1 µm. See Spec. [0067].
2 “[T]he ‘depending on’ language implies a functional or selective relationship (i.e., the basis weight is chosen based on the fiber diameter to enable the subsequent ‘thereby’ clause for uniform capture and distribution”). Emphasis added.
3 See e.g., Xu et al., US 2011/0265656 A1, [0020] (a macropore is defined as having a diameter greater than 50 nm, which converts to 0.05 micron).