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 1–3, 9–15 and 17–22 are rejected under 35 U.S.C. 103 as being unpatentable over Hassenboehler, Jr. et al., US 5,730,923 in view of Fox et al., US 2008/0022642 A1.
Regarding claim 1, Hassenboehler teaches a nonwoven web that can be used for gas filtration, and that can be manufactured from a spunbond material. See Hassenboehler col. 3, ll. 18–28, col. 4, ll. 30–39. The nonwoven web reads on the claimed “air-filtration article consisting of a spunbond air filtration web.” The spunbond material comprises meltspun bonded electret fibers with an average filament diameter of 7 to 50 microns. Id. at col. 3, ll. 18–29, col. 15, l. 62–16, l. 22. The prior art diameter range of 7 to 50 microns overlaps with the claimed range of “an Actual Fiber diameter of from 5.0 to 8.0 microns” establishing a prima facie case of obviousness. See MPEP 2144.05(I) (In the case where the claimed ranges overlap or lie inside ranges disclosed by the prior art, a prima facie case of obviousness exists). Note that the Examiner finds that there is not a patentable distinction between the average filament diameter of Hassenboehler and the actual fiber diameter described in the claim, because the terms average filament diameter and actual fiber diameter merely represent, at most, different techniques of measuring the diameter of the fiber, but that the fiber diameter reported would be substantially the same.
The nonwoven web exhibits a mean flow pore size of 9.4 microns, which is within the claimed range of 10 to 14 microns. See Hassenboehler col. 11, ll. 54–63. The nonwoven web also exhibits a ratio or mean flow pore size to pore size of 0.817, which is within the claimed range of at least 0.80 to less than 1.0. Id. Note that this ratio is determined by dividing the mean flow pore size (i.e., 9.4 microns) by the difference between the largest and smallest pore sizes (i.e., 17.5 minus 6 microns).
The nonwoven web is the only air-filtration layer of the air-filtration article, at least before it is incorporated with other materials, as it is described as “a nonwoven web” (singular). See Hassenboehler col. 3, ll. 18–29. The nonwoven web is substantially free of nanofibers, because there is no discussion of the nonwoven web comprising nanofibers when it is manufactured from a spunbond material. The nonwoven web has a thickness of 2 to 200 mils, which converts to 0.051 to 5.08 mm. Id. at col. 8, ll. 25–34. The prior art range of 0.051 to 5.08 mm overlaps with the claimed range of 0.6 to 1.5 mm, establishing a prima facie case of obviousness.
It is noted that the pore size and thickness values of Hassenboehler are reported for an embodiment where the nonwoven web is manufactured from a meltblown material instead of a spunbond material. See Hassenboehler col. 10, l. 36–col. 11, l. 63. The reference silent as to the pore size and thickness values for the nonwoven web when it is a spunbond. But Hassenboehler teaches that the product that is produced can be a meltblown web or a spunbond web. Id. at col. 4, ll. 31–35. Therefore, it would have been obvious for the nonwoven web, when manufactured from a spunbond material, to have the same pore size and thickness values as the meltblown web, because the reference says that the product can be made using meltblowing or spunbonding.
Hassenboehler differs from claim 1 because it is silent as to the electret fibers of the spunbond material being “autogenously bonded1.” But the nonwoven web is manufactured in a process where a precursor nonwoven web is subjected to a post-treatment process to provide the web with reduced pore sizes and a narrower pore size distribution. See Hassenboehler col. 3, ll. 18–29. The precursor web comprises a spunbond web that includes at least some fiber-to-fiber bonding. Id. at col. 8, ll. 38–46, col. 16, ll. 1–22. The fiber-to-fiber bonding can be achieved using various techniques including inherent fiber-to-fiber fusion, point bonding, calendering, fiber entanglement, needling or otherwise thermal bonding at a plurality of points. Id. The bonding must be relatively strong so that the filament segments can locally elongate, buckle and bend during the post-treatment process. Id. at col. 16, ll. 1–22.
With this in mind, Fox teaches a meltspun (i.e., spunbond) monolayer web that can be used for air filtration. See Fox [0037], [0044]. The meltspun web comprises fibers that are autogenously bonded to one another in a bonding operation at an elevated temperature without application of solid contact pressure. Id. at [0032], [0040]. The monolayer web is relatively strong, with enough structural integrity so that it can undergo post-treatment, such as pleating, with the material being self-supporting. Id. at [0040]. The monolayer web is beneficial because the material can be fully recycled because the fibers all have the same polymeric composition. Id. at [0011].
It would have been obvious for the spunbond precursor material of Hassenboehler to be manufactured using the technique used to fabricate the meltspun monolayer web of Fox to provide a material that can be fully recycled.
Regarding claim 2, Hassenboehler as modified teaches the limitations of claim 1, as explained above.
Hassenboehler differs from claim 2 because it is silent as to the solidity of the nonwoven web being 8 to 18.0%, the basis weight being 60 to 200 grams per square meter (gsm), and a Gurley stiffness being at least 500 mg, as claimed.
But, as noted in the rejection of claim 1 above, Fox teaches a meltspun (i.e., spunbond web) that is useful for gas filtration, where the web has a solidity of 11.4%, a basis weight of 99 gsm and a Gurley stiffness of 500 mg. See Fox Table 2A, [0078].
It would have been obvious for the nonwoven web of Hassenboehler to have a solidity of 11.4%, a basis weight of 99 gsm and a Gurley stiffness of 500 mg, because these are suitable values for a spunbond web usable for gas filtration.
Regarding claim 3, Hassenboehler in view of Fox teaches that the meltspun autogenously bonded electret fibers are monocomponent fibers because Hassenboehler teaches that the fibers are made from a single type of polymer (i.e., PP) (see Hassenboehler col. 16, ll. 33–37), with Fox teaching that the fibers are monocomponent fibers (see Fox [0019], [0036]).
Regarding claim 9, Hassenboehler teaches that the nonwoven web has a thickness of 2 to 200 mils, which overlaps with the claimed range of 32 to 43 mils, establishing a prima facie case of obviousness. See Hassenboehler col. 8, ll. 25–34.
Regarding claims 10–14, Hassenboehler as modified teaches that the nonwoven web has substantially the same structure as the air-filtration article of claim 1, as noted above. Therefore, the nonwoven web is presumed to exhibit the same properties as the claimed air-filtration article, including pressure drop, Quality Factor, Capture Efficiency and Media CCM. See MPEP 2112.01(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).
Regarding claim 15, Hassenboehler teaches that the nonwoven web is substantially free of meltblown fibers because it is made of a spunbond material instead of a meltblown material. See Hassenboehler col. 3, ll. 18–28, col. 4, ll. 30–39.
Regarding claim 17, Hassenboehler as modified teaches the limitations of claim 1, as explained above.
Hassenboehler differs from claim 17 because it is silent as to the nonwoven web comprising rows of oppositely-facing pleats, as claimed.
But, as noted in the rejection of claim 1 above, Fox teaches a meltspun (i.e., spunbond) web that is useful for gas filtration where the web is pleated into rows of oppositely-facing pleats. See Fox Fig. 1, [0036]. It would have been obvious for the nonwoven web of Hassenboehler to be pleated into rows of oppositely facing pleats to increase the surface area of the nonwoven web.
Regarding claims 18–20, Hassenboehler teaches that its nonwoven web can be used as an HVAC filter. See Hassenboehler col. 17, ll. 4–10. An HVAC filter is used to filter particulate matter of an air stream passing through the filter (claim 18). An HVAC filter is installed in an air-handling unit of a forced-air HVAC system (claim 19). An HVAC system is a room-air purifier (claim 20).
Regarding claims 21–22, Hassenboehler teaches that the nonwoven web can have an efficiency of 99.199% for NaCl generated at a mass mean diameter of 0.1 µm, which is close enough to the claimed range of a capture efficiency of 99.97 percent or greater when tested with either NaCl generated at a mass mean diameter of 0.26 microns at 32 liters per minute or DOP generated at a mass mean diameter at 32 liters per minute, to establish a prima facie case of obviousness. See Hassenboehler Table III, col. 15, ll. 25–37; MPEP 2144.05(I) (a prima facie case of obviousness exists where the claimed ranges do not overlap with the prior art but are merely close).
Response to Arguments
35 U.S.C. 103 Rejections
The Applicant argues that Hassenboehler fails to teach that the fibers of the spunbond precursor material are “autogenously bonded” as required by claim 1. See Applicant Rem. filed June 20, 2025 (“Applicant Rem.”) 5–6.
The Examiner finds the Applicant’s arguments persuasive. However, it would have been obvious for the fibers of the spunbond precursor material of Hassenboehler to be autogenously bonded in view of Fox, for the reasons explained in the 35 U.S.C. 103 rejection of claim 1 above.
The Applicant also argues that the claims are non-obvious over the cited prior art, asserting that the claimed numerical ranges are critical for yielding unexpected results. See Applicant Rem. 6–7. Specifically, the Applicant argues that the claimed invention solves the long-standing problem of the inability to achieve HEPA filtration with meltspun/spunbond webs, absent the inclusion of nanofibers or meltblown fibers. Id. The Applicant cites to Working Examples WE-1 through WE-6 from the disclosure, which achieved HEPA filtration, and argues that there are no teachings in the art that would lead a person of ordinary skill in the art to expect such a combination of parameters would achieve HEPA filtration. Id.
The Examiner respectfully disagrees. HEPA filtration is defined in the Applicant’s specification as a particle capture efficiency of 99.97% of 0.3 µm particles. See Spec. p 6, l. 34–p. 7, l. 9. Hassenboehler provides an example where the nonwoven web has an efficiency of 99.199% for 0.1 µm particles. See Hassenboehler col. 15, ll. 25–37 (Table III, Sample CWK-3), col. 14, ll. 59–67. This example in Hassenboehler either teaches HEPA filtration (because the efficiency would be greater than 99.199% for 0.3 µm particles, which are larger than the 0.1 µm particles tested), or is so close to HEPA filtration that slightly adjusting the parameters, such as reducing pore size or enhancing electrostatic charge, to increase the efficiency from 99.199% to 99.97% would have been expected. Therefore, the Examiner respectfully disagrees with the Applicant’s arguments that the claims are non-obvious for yielding unexpected results, because the efficiency reported by Hassenboehler is either the same or so close to HEPA filtration such that the results would have been expected.
The Applicant further argues that the best filtration results of Hassenboehler, presented in Table III achieve filtration efficiencies of 99.101% and 99.199% (penetration of 0.889% and 0.801%, respectively). See Applicant Rem. 7. The Applicant argues that Working Examples WE-1 through WE-6 presented on p. 36, Table 1 of the specification achieved penetrations as low as 0.002 to 0.008% (99.992 to 99.998% efficiency). The Applicant argues that Working Examples WE-1 through WE-6 exhibit better penetration than that achieved by Hassenboehler by orders of magnitude. Id. Therefore, it is argued that the Applicant as filed contains results that are unexpected in view of Hassenboehler. Id.
The Examiner respectfully disagrees. The penetration values of Working Examples WE-1 to WE-6 of 0.002 to 0.008% are not commensurate in scope with the claimed invention. This is because dependent claim 22 indicates that the air-filtration article achieves a penetration of 0.03% or less, as the efficiency is 99.97% or greater. Therefore, because the data presented in WE-1 to WE-6 is not commensurate in scope with the claims, the Applicant’s arguments that the claimed invention achieves unexpected results is unpersuasive.
Also, the Examiner maintains that the efficiencies of 99.101% and 99.199% for 0.1 µm particles reported in Hassenboehler are very close to the 99.992 to 99.998% efficiency for 0.3 µm particles reported in Table 1 of the disclosure. This is because the efficiencies for Hassenboehler would be greater than 99.101% and 99.199% when filtering 0.3 µm particles because 0.3 µm particles are larger than 0.1 µm particles. Also, the efficiency of Hassenboehler could be increased slightly from 99.199% to 99.993% by, for instance, reducing pore size or enhancing electrostatic charge.
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.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
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.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
T. BENNETT MCKENZIE
Primary Examiner
Art Unit 1776
/T. BENNETT MCKENZIE/Primary Examiner, Art Unit 1776
1 “Autogenously bonded” has the special definition of “a nonwoven web bonded by a bonding operation that involves exposure to elevated temperature without the application of solid contact pressure onto the web.” See Spec. p. 3, ll. 1–2.