DETAILED ACTION
This action is in response to the remarks filed 09/03/2026, in which no claims have been amended and claims 1-4 and 6-15 are pending and ready for examination.
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 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 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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1-4, 6 and 10-12 are rejected under 35 U.S.C. 103 as being unpatentable over S.Sh. Homaeigohar, K. Buhr, K. Ebert, Polyethersulfone electrospun nanofibrous composite membrane for liquid filtration, Journal of Membrane Science, Volume 365, Issues 1–2, 2010, Pages 68-77 (hereinafter “Homaeigohar”) in view of X. Tang et al., "Development and characterisation of nanofiber films with high adhesion," 2011 IEEE 61st Electronic Components and Technology Conference (ECTC), Lake Buena Vista, FL, USA, 2011, pp. 673-677 (hereinafter “Tang”).
Regarding Claim 1 Homaeigohar discloses a filter element (Fig. 2) comprising a filtration media for use in fluid filtration applications, wherein the filtration media comprises:
a first layer on an upstream side of the self-cleaning filtration media, the first layer comprising polyethersulfone nanofibers having a diameter of 260±110 nm (i.e. 150-370 nm); and
a second layer (see Sec. 3.2. and 4) on a downstream side of the self-cleaning filtration media, the second layer comprising a PET nonwoven substrate; and
wherein the first layer is coated onto the second layer (electrospun directly onto), and an upstream surface of the filter element is a surface of the first layer; Abstract, Introduction, Sec. 2.2., Table 2.
With specific regard to the PES nanofiber first layer being on the upstream side of the second supporting layer, it is disclosed that the PET nonwoven is disclosed as a “sub-layer” and the particles when filtered accumulate on the surface of the nanofibers as the uppermost layer (see Fig. 13 and 3.3.3. Retention tests with particle suspensions ), and therefore the nanofiber layer must be the upstream layer and/or would have been obvious to make the upstream layer.
Homaeigohar does not disclose the first layer further comprising an adhesive with the adhesive and the polyethersulfone nanofibers electrospun simultaneously such that the adhesive is applied at the same time the polyethersulfone nanofibers are being formed.
However Tang discloses electrospinning a nanofiber mat wherein hotmelt was added into the electrospinning solution, in addition to the fiber polymer, to improve the adhesion properties of the film, and resulted in films having a shear strength 2 times better than the case without the hotmelt addition (Abstract, Experimental Procedure).
Therefore, at the time of filing, it would have been prima facie obvious to one of ordinary skill in the art to modify the filter media of Homaeigohar by adding hotmelt adhesive into the electrospinning solution with the polyethersulfone as disclosed by Tang in order to improve the adhesion properties of the nanofiber film including shear stress.
The hotmelt adhesive in the electrospinning solution with the polyethersulfone thus results in the adhesive and the polyethersulfone nanofibers electrospun simultaneously such that the adhesive is applied at the same time the polyethersulfone nanofibers are being formed, as claimed.
Note: With regard to the filtration media being “self-cleaning” or “for use in hydrocarbon fluid filtration applications” this is a functional limitation which is not limiting because the structure disclosed by Homaeigohar in view of Tang would be capable of “self-cleaning” or “for use in hydrocarbon fluid filtration applications”; Claims directed to an apparatus must be distinguished from the prior art in terms of structure rather than function (see MPEP 2114).
Regarding Claims 2-3 Homaeigohar in view of Tang discloses the filter element of claim 1, wherein the polyethersulfone nanofibers have a diameter of 260±110 nm (i.e. 150-370 nm); Homaeigohar Table 2.
Since the range disclosed overlaps the range claimed, the range recited in the claim is considered prima facie obvious. Overlapping ranges are prima facie evidence of obviousness. It would have been obvious to one having ordinary skill in the art to have selected the portion of the disclosed range that corresponds to the claimed range. See MPEP 2144.05(I).
Regarding Claim 4 Homaeigohar in view of Tang discloses the filter element of claim 1, wherein the polyethersulfone nanofibers of the first layer are electrospun onto the second layer, Homaeigohar Introduction, Sec. 2.2.
Regarding Claim 6 Homaeigohar in view of Tang discloses the filter element of claim 1, wherein the adhesive is electrospun with the polyethersulfone in an amount of 0 to 5 wt% (Tang pg. 674, left column, bottom paragraph).
Regarding Claim 10 Homaeigohar in view of Tang discloses the filter element of claim 1, which is inherently chemically resistant to gasoline, petroleum, alcohols, engine oil, and transmission oil due to the PES and PET polymer materials inherent properties; see MPEP 2112.02.
Regarding Claim 11 Homaeigohar in view of Tang discloses the filter element of claim 1, wherein the nonwoven substrate of the second layer is disclosed to only be composed of PET and thus is expected to be free of glass fibers.
Regarding Claim 12 Homaeigohar in view of Tang discloses the filter element of claim 1, wherein the nonwoven substrate of the second layer comprises PET, i.e. synthetic fibers.
Claims 7-9 and 13-14 are rejected under 35 U.S.C. 103 as being unpatentable over Homaeigohar in view of Tang further in view of US 2012/0061332 Al (hereinafter “Kas”) and US 2011/0079553 A1 (hereinafter “Thompson”).
Regarding claims 7-9 and 13-14 Homaeigohar in view of Tang discloses the filter element of claims 1 and 12, but does not disclose (claim 7) wherein the nonwoven substrate of the second layer comprises up to 20% by weight glass microfibers, (claim 8) wherein the wet laid nonwoven further comprises a resin applied to a weight of 10 % to 25 % of the weight of the wet laid nonwoven, or (claim 9) wherein the second layer comprises 3 % to 20 % glass microfibers, or (claim 13) wherein the nonwoven substrate of the second layer has a basis weight in a range of between 75 gsm and 200 gsm, or (claim 14) wherein the nonwoven substrate of the second layer comprises a resin applied to a weight of 10 % to 25 % of the weight of the nonwoven substrate.
However, with regard to the supporting layer, it is disclosed that the nanofibers are spun directly onto a stronger more rigid support in order to reduce problems with handling the nanofiber mats due to electrostatic charges during the electrospinning and uses a PET nonwoven, but does not disclose as specific reason for choosing the PET nonwoven, or the details of said PET nonwoven and therefore it is seen as obvious to substitute other nonwovens as there is no criticality to the PET nonwoven chosen (1. Introduction),
Further Kas discloses a similar composite nanofiber layer filter medium (Abstract), wherein the nanofibers may be made of polyether sulfone [0054]-[0055], and the porous supporting substrate may be made of various materials including nonwovens or paper [0061], wherein the nanofibers and the substrate are bonded to each other via heated means [0062]-[0068]. Thus the nanofibers would be expected to bond to paper in the heat treatment, such as disclosed by Homaeigohar.
Therefore, at the time of filing, it would have been prima facie obvious to one of ordinary skill in the art to modify the filter media of Homaeigohar in view of Tang by substituting for the supporting layer a porous paper substrate as disclosed by Kas because this involves the simple substitution of known porous supporting layers for a PES nanofiber layer to obtain the predictable result of forming a successful supported PES nanofiber layer filtration media.
Kas is silent to the composition of the paper.
However, Thomson discloses a nonwoven filtration media which may include a mixture of microglass fibers with synthetic fibers, where the synthetic fibers may be “at least about 50 wt%” to and including 100% of the mixture [0055] with the reminder microglass and wherein the synthetic fibers including regenerated cellulose [0056], and may additionally include wood pulp cellulose [0058], and which may include a binder resin in the nonwoven filter media in an amount of less than about 10 wt% binder [0059]-[0060] and wherein the nonwoven may be formed by wetlaid processes , [0089],[0096]. Thus the media may comprise a wetlaid non-woven of 100 wt% cellulose fibers.
Therefore, at the time of filing, it would have been prima facie obvious to one of ordinary skill in the art to modify the filter media of Homaeigohar in view of Tang and Kas by substituting for the paper supporting layer the cellulose wet laid nonwoven media as disclosed by Thomson because this involves the simple substitution of known porous paper filtration material for another to obtain the predictable result of successful paper supported filtration media formation.
Thus:
Regarding Claims 7 and 9 the second layer may comprise 0 to 50 wt% glass microfibers; Thomson [0055].
Regarding Claim 8 the wet laid nonwoven may further comprise a binder resin in an amount of less than about 10 wt% of the nonwoven Thomson [0059]-[0060]. The range of “less than about 10 wt%” is seen to overlap with the range claimed that stars at 10 wt% because “about 10 wt%” is seen to include values slightly over 10 wt%.
Regarding Claim 13 the nonwoven substrate of the second layer is that disclosed by Thomson which is disclosed to have a basis weight of from 20-200 gsm, [0064].
Regarding Claim 14 wherein the wet laid nonwoven may further comprise a binder resin a binder resin in an amount of less than about 10 wt% of the nonwoven Thomson [0059]-[0060]. The range of “less than about 10 wt%” is seen to overlap with the range claimed that stars at 10 wt% because “about 10 wt%” is seen to include values slightly over 10 wt%.
Since the range(s) disclosed overlaps the range(s) claimed, the range(s) recited in the claim is/are considered prima facie obvious. Overlapping ranges are prima facie evidence of obviousness. It would have been obvious to one having ordinary skill in the art to have selected the portion of the disclosed range(s) that corresponds to the claimed range. See MPEP 2144.05(I).
Claim 15 is rejected under 35 U.S.C. 103 as being unpatentable over Homaeigohar in view of Tang further in view of US 2004/0203306 A1 (hereinafter “Grafe”).
Regarding Claim 15 Homaeigohar in view of Tang discloses the filter element of claim 1, wherein the self-cleaning filtration media has a stiffness of at least 7,000 mg when measured according to TAPPI T489 om-92.
However Grafe discloses that typical stiffness values for filter media are about 350-12,000 mg according to TAPPI T-543 om-00; [0062], [0065].
Therefore, at the time of filing, it would have been prima facie obvious to one of ordinary skill in the art to modify the filter media of Homaeigohar in view of Tang by forming the media to have a stiffness of from 350-12,000 mg according to TAPPI T-543 om-00 as disclosed by Grafe because this is a stiffness known to make functional filtration media.
While the testing standard is “TAPPI T-543 om-00” and not the “TAPPI T489 om-92”, they are similar test for the same stiffness values and are thus seen to be equivalent and/or close enough that the range disclosed would still overlap the range claimed. Since the range disclosed overlaps the range claimed, the range recited in the claim is considered prima facie obvious. Overlapping ranges are prima facie evidence of obviousness. It would have been obvious to one having ordinary skill in the art to have selected the portion of the disclosed range that corresponds to the claimed range. See MPEP 2144.05(I).
Response to Arguments
Applicants’ arguments filed 09/03/2026 have been fully considered but they are not persuasive.
In response to Applicants’ argument that Tang is non-analogous art to the claimed invention; the Examiner disagrees. MPEP 2141.01(a), states that “a reference is analogous art to the claimed invention if: (1) the reference is from the same field of endeavor as the claimed invention (even if it addresses a different problem); OR (2) the reference is reasonably pertinent to the problem faced by the inventor (even if it is not in the same field of endeavor as the claimed invention)”. Tang and Applicants’ invention are all related as to the same field of endeavor, electrospinning a mixture of polymer and adhesive to for nanofibrous materials, and further it is seen to be related to the same problem faced by the inventor, i.e. assisting holding nanofibers of a nanofiber layer to a supporting layer (see instant specification [00022]). Applicants argue much more narrow definitions of the field of endeavor and problem faced by the inventor, but references need not be so narrowly related to the invention. Tang’s disclosure of how to better attached nanofibers to a support during electrospinning would apply broadly to all electrospun materials depositing on a support, absent a teaching away.
In response to Applicants’ argument that there is no motivation to add adhesive during spinning and no expectation of success in either adhesion or other properties; the Examiner disagrees. Applicants argue that because Homaeigohar discloses a heat treatment to bond the PES/PET composite it would not have been obvious to further introduce an adhesive to assist in the bonding, and that nothing in Tang discloses the bonding would improve over this disclosed thermal bonding, particularly because Tang is not directed to filter membranes. However, Tang clearly discloses the hot melt adhesive is added to assist in bonding the nanofibers to a substrate, which the substrate is not the same as in the instant invention, and the shear test results are with regard to shearing the adhered nanofiber film from a circuit surface, the result still clearly demonstrate the fibers had more adherence, even if the test was not the same forces a filter would be expected to be subjected to. Further, while Homaeigohar discloses a thermal bonding method, as Tang discloses directly adding a hot melt adhesive (i.e. an adhesive that works when heated), one of skill in the art would have a reasonable expectation that adding it to the fibers of Homaeigohar would increase adhesion even after the heat treatment, absent evidence to the contrary, and further would expect it to provide better adhesion for processing of the membrane before it is heat treated for bonding. With regard to maintain membrane properties, as Applicants noted in their arguments, Tang directs one of skill in the art to optimize conditions such as solution viscosity, hot melt concentration and temperatures to obtain the results they desire, while not in regard to filtration, the electrospinning process and forming nanofiber mats are the same process and one of skill in the art would understand how to apply it to a filter, optimizing as needed to achieve desired results. Applicants cite Figs. 5-6 of Tang, which shows surface morphology change from adding hot melt, as reason why there would be no expectation of success, but just because the morphology changes in one example does not imply this is cannot be adjusted through means as suggested by Tang, or that it would not be suitable for a filter. Obviousness does not require absolute predictability; MPEP 2143.02.
Terminal Disclaimer
The terminal disclaimer filed 09/03/2026 is noted but been approved and thus the Double Patent Rejections are withdrawn.
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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/ERIC J MCCULLOUGH/ Examiner, Art Unit 1773
/BENJAMIN L LEBRON/ Supervisory Patent Examiner, Art Unit 1773
