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 .
Priority
Acknowledgment is made of applicant’s claim for foreign priority under 35 U.S.C. 119 (a)-(d). The certified copy has been filed in parent Application No. 10 2023 103 969.5, filed on 02/17/2023.
Response to Amendment
The amendment filed on May 29, 2026 is acknowledged. Claims 1-7, 9-10 is currently amended and remains pending in the application. Claim 8 is canceled. Claims 11-21 are newlypresented and remain pending in the application.
Applicant’s replacement drawing sheet and amendment have overcome each and every objection previously set forth in the Non-Final Office Action mailed on February 09, 2026. The previous rejections under 35 U.S.C. 102 and 35 U.S.C. 103 are withdrawn due to Applicant’s amendment. New rejections follow.
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 non-obviousness.
Claims 1, 9-10, and 15-21 are rejected under 35 U.S.C. 103 as being unpatentable over Rammig et al. U.S. Pub. No. 6966939 B2, November 22, 2005 (hereinafter “Rammig”) in view of Keerl et al. DE 102013021071 A1, June 18, 2015 (hereinafter “Keerl”).
Regarding claim 1, Rammig discloses a filter element comprising a multi-layer filter structure E (fig. 1) for the dust extraction from gases, suitable for use in stationary or mobile dust cleaning devices, including air filters for motor vehicles (col. 1, lines 61-66 and col. 6, lines 17-21). The multiple-layer filter medium includes an inflow-side coarse dust filter layer (A), a fine dust filter layer (B), and a support layer (C), which are disposed behind one another in the direction from the inflow side to the outflow side (col. 1, lines 1-15, figs. 1-3). The coarse dust filter layer (A) functions as a prefilter layer for larger particles, the fine dust filter layer (B) functions as a fine filter layer, and the support layer (C) provides mechanical support for the fine dust filter layer (col. 3, lines 5-46). Rammig further discloses that the fibers of the coarse dust filter layer and/or the fine duct filter layer may be provided with an antimicrobial additive (col. 7, lines 15-18). However, Rammig fails to disclose that the third filter layer forms an outflow-side layer which is configured with a second anti-microbial finish.
Keerl discloses a multi-layer filter medium particularly suitable for filtering air supplied to the passenger compartment of a motor vehicle (paragraphs 0001-0004, 0025-0026). Keerl discloses filter layers containing antimicrobial substances to inhibit microbial growth, prevent microorganisms from spreading through the filter medium, and protect the filter medium against bacteria, fungi, mold, and other microorganisms (paragraphs 0010, 0012, and 0042-0043). Keerl discloses that the filter layer may be coated on opposite surfaces with antimicrobial substances. Paragraph [0038] explains that a filter layer may be coated on both sides with active substances and expressly describes and upper-side material coating containing an antimicrobial substance and an underside material coating containing an antimicrobial substance. Keerl further discloses that functionalized layers containing antimicrobial or anti allergenic substances may be advantageously be applied on the inflow side and/or the outflow side of the filter medium (paragraph 0045).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to configure Rammig’s outflow-side support layer C with a second antimicrobial finish, as taught by Keerl. A person of ordinary skill would have been motivated to make this modification to inhibit microbial growth and propagation the downstream surface of the filter, protect the filter medium from microbial contamination or penetration, and provide antimicrobial protection on both exposed sides of the multilayer filter.Keerls recognizes that the antimicrobial functionalization may be provided on the inflow side, the outflow side, or both sides, and that the antimicrobial treatment protects the filter medium from colonization and growth of microorganisms (paragraphs 0038, 0042-0043, and 0045).
Regarding claims 9 and 10, Rammig discloses the fibers of the coarse dust filter layer and/or the fine duct filter layer may be provided with an antimicrobial additive (col. 7, lines 15-18). However, Rammig fails to disclose (i) a further layer arranged at the outflow side and configured with an anti-microbial finish, and (ii) a layer configured as an adsorption layer comprising activated carbon.
Keerl discloses that a filter medium can be structured in multiple layers. Keerl discloses the order of airflow, for example, an antimicrobial filter layer can be applied, a particle filter layer, an odor filter layer, an activated carbon layer, and/or an anti-allergen filter layer can follow (paragraph 0014). Keerl further discloses that the first layer 2 then has the particle filter function, the second layer 3 the antimicrobial substance and the third layer 3 the anti-allergenic substance (fig. 1, paragraph 0036). For example, fig. 1 teaches a top-side coating of an antimicrobial material and third filter layer 4 a fabric coating on the underside containing an antimicrobial substance (paragraph 0038).
Additionally, Keerl discloses a filter layer can in particular be designed as an adsorption filter layer. This can, for example, itself consist of a multilayer structure comprising of activated carbon particles supported on carrier layers or an open pored foam with embedded activated carbon (paragraph 0048). Therefore, it would have been obvious to one of ordinary skill before the effective filing date of the claimed invention to modify the multilayer filter structure of Rammig to that taught by Keerl, in order to provide enhanced anti-microbial protection, allergen reduction, and odor removal in a predictable manner.
Regarding claim 15, Rammig discloses in claim 12 that the staple fibers of the coarse dust filter layer (A) have an average fiber diameter of 8.0 to 40 µm. Rammig’s disclosed range overlaps the claimed range of 30 to 50 µm over the interval of 30 to 40 µm. It would have been obvious to one of ordinary skill in the art at the time of the invention to select fibers within this overlapping range because Rammig identifies fiber diameter as a variable affecting the pore size gradient and filtration performance of the layer.
Regarding claim 16, Rammig discloses that the first filter layer, corresponding to coarse dust filter layer (A), has a fiber diameter gradient across its thickness. In particular, Rammig teaches that the coarser staple fibers are positioned on the side facing the inflow direction (F), whereas the fine staple fibers (H) are positioned on the side facing away from the inflow direction (col. 3, lines 1-15; fig. 3). Thus, Rammig discloses that the average diameter on the inflow side of the first filter layer is greater than the average fiber diameter on the outflow side of the first filter layer.
Regarding claim 17, Rammig fails to discloses that the first filter layer can separate fibers and coarse dusts in a size range of greater than 5 pm. However, Keerl discloses that a filter may be configured to remove particles having a diameter of 10 µm and greater, preferably 2.5 µm and greater (see claim 13). It would have been obvious to one of ordinary skill in the art at the time of the invention to configure Rammig’s coarse dust filter layer (A) to separate fibers and coarse dust greater than 5 µm, because Keerl expressly teaches filtering particle sizes encompassing particles greater than 5µm, and doing so at the upstream coarse filter would predictably prevent larger contaminants from prematurely loading the downstream fine filter.
Regarding claim 18, Rammig fails to disclose that the multiple- layer filter medium is pleated, and the pleated filter medium forms a gaiter. However, Keerl discloses that a multilayer motor-vehicle filter medium is preferably folded or corrugated to increase its filtration surface area and that the folded medium has a zigzag or wave-shaped fold profiles (paragraph 0025) Keerl further discloses a three-layer filter medium folded in a zigzag configuration to form a fold block (fig. 3; paragraph 0056). It would have been obvious to one of ordinary skill in the art at the time of the invention to form Rammig’s multilayer filter medium as the pleated fold pack taught by Keerl because Rammig expressly contemplates pleated filters (col. 6, lines 17-21) and Keerl teaches that pleating increases the available filter surface area.
Regarding claim 19, Rammig fails to disclose that the anti- microbial finish of the inflow-side first filter layer and the second anti-microbial finish of the outflow-side layer prevents user contact with germ-loaded substances from biological decomposition processes of separated biomass. However, Keerl discloses that the antimicrobial substances protect the filter medium and its layers against microorganisms, such as fungi, mold spores, bacteria, and algae, and inhibit the microorganisms from spreading through or growing across the filter medium (paragraph 0010). Keerl further discloses applying antimicrobial functionalization to the inflow side and/or the outflow side of the filter medium, with the active substances positioned for direct contact with microorganisms (paragraph 0045-0047). It would have been obvious to one ofordinary skill in the art at the time of the invention to provide the inflow-side and outflow-side layers of Rammig with the antimicrobial finishes taught by Keerl to inhibit microbial growth and biological decomposition of retained biomass.
Regarding claim 20, Rammig discloses that coarse dust filter layer (A) has pore size controlled by fiber diameter and compaction and further discloses controlling the fiber arrangement and pore-size gradient through carding, cross-lapping, one-sided needling, and thermal hardening (col.2, lines 14-23; col 3, lines 62 – col. 4, line 31). Rammig also discloses a coarse filter layer having a basis weight of 40 to 500 g/m2, a thickness of 1.5 to 6 mm, fiber diameters of 8 to 40 µm, an air permeability of 1000 to 4000 L/m2 (see claims 6-12). Rammig does not disclose a fiber spacing of 200 to 400 µm. However, it would have been obvious to one of ordinary skill in the art at the time of the invention to adjust the spacing between the fibers, including 200 to 400 µm, through routine optimization of the fiber arrangement, basis weight, thickness, and needling taught by Rammig. Rammig recognizes pore or fiber spacing as a result effective variable affecting air-flow, dust capture, and pressure drop. Selecting a suitable spacing would therefore have been a predictable optimization to provide coarse particle collection while maintaining air permeability.
Regarding claim 21, Rammig discloses that the coarser staple fibers are located on the side facing the inflow direction (fig. 3; col. 3, lines 1-15). Therefore, Rammig discloses that the average fiber diameter on the inflow-side of the first filter layer is greater than an average fiber diameter on the outflow-side. Rammig further discloses staple-fiber diameters of approximately 8 to 40 µm for the coarse dust filter layer (see claim 12). Rammig’s disclosed range overlaps the claimed range of 30 to 50 µm over the interval of 30 to 40 µm. It would have been obvious to one of ordinary skill in the art at the time of the invention to select fibers within this overlapping range because Rammig identifies fiber diameter as a variable affecting the pore size gradient and filtration performance of the layer.
Claims 2, 3, and 5 are rejected under 35 U.S.C. 103 as being unpatentable over Rammig and Keerl, as applied to claim 1, in further view of Ding CN 106693531 A, May 24, 2017 (hereinafter “Ding”).
Regarding claim 2, Rammig discloses that the first filter layer is formed as a nonwoven layer (col. 3, lines 38-55), but fails to disclose that the first filter layer is configured as a nonwoven layer of a PM 2.5 category. Ding discloses a nonwoven filter fabric 7 (figs. 1 and 2, paragraph 0018) that can remove PM2.5 and other small particles (paragraph 0012 and 0023). It would have been obvious to one of ordinary skill before the effective filing date of the claimed invention to configure the nonwoven first filter layer of Rammig in view of Keerl to meet a PM2.5 category, as taught by Ding, to yield improved filtration performance.
Regarding claim 3, Rammig discloses an anti-microbial additive (col. 7, lines 15-18) but failed to disclose that the anti-microbial finish comprises anti-bacterial and/or anti-viral and/or anti-allergenic and/or fungicidal substances. Ding discloses an antibacterial non-woven fabric 5 (fig.1, paragraph 0010 and 0023). When using, the air firstly passes through the antibacterial non-woven fabric 5, removing bacteria and dust particles, and inhibit the growth of bacteria, absorbing organic matter and peculiar smell through the active carbon layer (paragraph 0023). It would have been obvious to one of ordinary skill before the effective filing date of the claimed invention to select known anti-microbial substances, as these are well known classes of microbial agents commonly used in air filtration media depending on the intended microbial target.
Regarding claim 5, Rammig discloses the fine dust filter layer is a microfiber nonwoven produced according to the melt-blown process, having small fiber diameter and progressively decreasing pore sizes to capture fine dust particles (figs. 1-3, col. 3, lines 16-22) but fails to disclose the second filter layer includes a very high efficiency filter medium. Ding discloses high efficiency particulate air (HEPA) filter layer 4 (figs. 1-2, paragraph 0018, 0021, and 0023). It would have been obvious to one of ordinary skill before the effective filing date of the claimed invention to include a very high efficiency filtration medium within a multilayer filter structure, as such modification will yield predictable results in enhanced filtration performance.
Claims 4 and 11-13 are rejected under 35 U.S.C. 103 as being unpatentable over Rammig, Keerl, and Ding, as applied to claim 3, in further view of Uenen U.S. Pub. No. 20210213379 A1, July 15, 2021.
Regarding claims 4 and 11, Rammig discloses an antimicrobial finish but fails to disclose the anti-microbial finish comprises a fruit acid, wherein the fruit acid is citric acid. Uenen discloses the antiallergenic substances of the filter medium may contain fruit acids, for example citric acid (paragraph 0017-0019). It would have been obvious to one of ordinary skill before the effective filing date of the claimed invention to select citric acid, as it is an anti-microbial fruit acid commonly used to inhibit microbial growth in air filtration applications.
Regarding claim 12 and 13, Rammig fails to disclose the citric acid is in a concentration of 20 to 25 g/m2 and the anti- microbial finish contains an anti-allergenic substance in a concentration of 2 to 250 g/m2. However, Uenen discloses the antiallergenic substances are present in particular in a concentration of 2-250 g/m2, particularly preferably in a concentration of 20-25 g/m2 given the use of citric acid. This ensures a good antiallergenic action of the filter medium (paragraph 0017). It would have been obvious to one of ordinary skill in the art at the time of the invention to employ the citric acid and anti-allergenic substance of the filter medium in the concentrations taught by Uenen because Uenen expressly teaches that those concentrations provide effective anti-allergenic activity.
Claims 6, 7, 14 are rejected under 35 U.S.C. 103 as being unpatentable over Rammig, Keerl, and Ding, as applied to claim 5, in further view of Komatsu et al. JP 2007301436 A, November 22, 2007 (hereinafter “Komatsu”).
Regarding claims 6 and 7, Rammig fails to disclose that the filter medium has nanofibers and a porous membrane. Komatsu discloses an air filter media 10 (fig. 1, paragraph 0009) includes a nanofiber structure layer 12, which is made of a sheet-like fiber structure in which nanofibers 12a are three-dimensionally entangled (paragraph 0009). Komatsu further discloses an upstream porous body layer 14 that is laminated integrally with the nanofiber structure layer 12 is a smooth surface that is free from fibrous fluff (paragraph 0012) and a downstream porous layer 16 supports the nanofiber structure layer 12 from the downstream side of filtration to prevent the nanofiber structure layer 12 from being damaged by wind pressure or the like applied by the gas to be filtered (paragraph 0013). It would have been obvious to one of ordinary skill before the effective filing date of the claimed invention to incorporate the nanofiber and porous membrane structure taught by Komatsu into the fine filter layer of Rammig, as modified by claim 5, in order to provide mechanical stability and further improve fine-particle filtration efficiency.
Regarding claim 14, Rammig fails to disclose the nanofibers have a mean diameter of 100 to 300 nm. However, Komatsu discloses an air filter medium having a nanostructure layer (12) containing three-dimensionally entangled nanofibers (12a), wherein the fiber diameter of the nanofibers (12a) is 500 nm or less because the filtered gas becomes easier to escape as the fiber diameter becomes smaller than about 500 nm (paragraphs 0009 and 0015). It would have been obvious to one of ordinary skill in the art at the time of the claimed invention to select a mean nanofiber diameter of 100 to 300 nm because the claimed range is encompassed by Komatsu’s disclosed range of 500 nm or less and represents selection of a suitable value from a known range to obtain the predictable fine-particle filtration and gas-permeability benefits taught by Komatsu.
Response to Arguments
Applicant's arguments filed 07/02/2026 have been fully considered but they are not persuasive.
Applicant argues that Keerl fails to disclose an inflow-side antimicrobial finish and a second antimicrobial finish on the outflow-side layer because Keerl (DE 102013021071 A1) permits various layer arrangements. This argument is NOT persuasive.
Keerl expressly teaches a multilayer filter medium including antibacterial functionalization of filter layers and further teaches that the functionalized layer may be applied on the upstream (inflow) side and/or the downstream (outflow) side of the filter medium (paragraph 0045). The disclosure of alternative layer arrangements does not negate the express teaching of antimicrobial treatment on either side of the filter medium, nor does it teach away from the claimed arrangement. One of ordinary skill in the art would have found it obvious to apply Keerl’s known antimicrobial finish to the outflow-side support layer of Rammig (U.S. 6966939 B2) in order to inhibit microbial growth and improve filter hygiene, yielding no more than the predictable use of prior-art elements according to their established functions.
Conclusion
THIS ACTION IS MADE FINAL. 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.
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/M.N.E./Examiner, Art Unit 1776
/Jennifer Dieterle/Supervisory Patent Examiner, Art Unit 1776
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