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 .
Response to Amendment
The response filed 13 April 2026 has been entered.
Claims 1, 7-9, 14-17, and 23 remain pending in the application, wherein none of the claims have been amended.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1, 7-9, 14-17, and 23 are rejected under 35 U.S.C. 103 as being unpatentable over Carredo (US PGPub. No. 2021/0154610, previously cited) in view of Perera et al. (US PGPub. No. 2020/0338493, previously cited) in view of Setlock (WO 2019/113032, previously cited) and in view of Leonard (US Pat. No. 3,619,718, previously cited).
Claim 1: Carredo teaches an air filter with a porous copper layer having natural antimicrobial property (paragraph 0002). The porous copper layer can be produced from copper-sintered-foam or open-cell copper foam (paragraph 0027) permanently or removably coupled to a base filter layer (i.e. a substrate) (paragraph 0020). Carredo teaches that open-cell copper foams can be manufactured by various methods including chemical vapor deposition or electro-plating over a non-copper core to produce a porous copper foam structure resembling that of the copper alloy metal (paragraph 0045) (i.e. the substrate is infiltrated and coated with the copper antibacterial metallic foam). Since copper is a metal and is taught to have natural antimicrobial property (paragraph 0002) and be produced as a foam (paragraph 0027) coupled on a base filter layer (i.e. on a substrate) (paragraph 0020), this is considered to teach an antimicrobial metallic foam on a substrate. Carredo teaches that the natural antimicrobial and self-sanitizing properties of copper is due to the atomic structure causing holes in bacterial cell membranes and disrupting viral coats so that pathogens cannot function or reproduce (i.e. deactivating the microorganisms) and respiratory viruses including coronaviruses were rapidly deactivated within minutes by copper surfaces (paragraph 0066). Carredo teaches that the air filter is a multilayer comprising at least one porous copper layer coupled to a base filter layer, which can be any known air filter or filter material (paragraph 0020), and conventional air filter materials include glass fibers (i.e. fiberglass) (paragraph 0003). However, the disclosure of Carredo is focused solely on copper as the antimicrobial (i.e. Carredo does not teach other metallic antimicrobial materials).
In a related field of endeavor, Perera teaches an air filter comprising an antimicrobial or antibacterial material (paragraph 0001), comprising metal particles that possess antimicrobial properties (paragraph 0006). Perera teaches that the metal may be present as a metal, a metal compound, a metal alloy, or combination of these and is preferably selected from one or combination of platinum, titanium, copper, gold, silver, zinc, etc. (paragraph 0053). Suitable compounds include copper oxide, zinc oxide, silver oxide, etc. (paragraph 0054).
As Carredo and Perera each teach an air filter that incorporates metals having antimicrobial properties, they are analogous. It would have been obvious to one of ordinary skill in the art before the effective filing date to modify the air filter having a base filter layer of glass fibers or fabric (i.e. glass fibers and fabric are materials known to be insulators) of Carredo by substituting the copper foam to be a foam made of any of the antimicrobial metals or metal compounds, such as silver (i.e. metallic silver is known to be a conductive material as a property of metals) taught by Perera as this is considered a simple substitution of one element for another element known to perform the same function (see MPEP § 2143), and one would have had a reasonable expectation of success. However, although Carredo teaches that the porous layer can be produced from conventional manufacturing processes, neither Carredo nor Perera specifically teach the instantly claimed method of forming the antimicrobial foam.
In a related field of endeavor of producing a coated or infiltrated substrate, Setlock teaches a method of making metal catalysts (paragraph 0003) that is a metal foam (paragraph 0010). The method includes applying a reaction mixture of a metal salt solution with a corn syrup reducing agent to a substrate to produce a coated or infiltrated substrate and heating (paragraph 0004). The metal salt may be a nitrate salt etc. that may be dissolved in methanol, and the metal may be copper, silver etc. (i.e. silver nitrate; i.e. a silver-containing precursor) (paragraph 0005). Setlock teaches that the weight ratio of metal salt-to-corn syrup can be adjusted to tailor the pore and grain size (paragraph 0049). The catalyst can be used in a variety of applications including filters (paragraph 0056).
As Carredo and Setlock both teach a metal foam for a filter, they are analogous. It would have been obvious to one of ordinary skill in the art before the effective filing date to modify the antimicrobial air filter of Perera-modified Carredo to include where the porous layer is produced using the known process taught by Setlock as this is considered a simple substitution of one known element (i.e. the generally taught production by any conventional process) for another known element (i.e. the process taught by Setlock) as both are known to produce a porous layer/metal foam that can be used for filters, and one would have had a reasonable expectation of success. Furthermore, although Setlock does not specify the instantly claimed ratio of solution (i.e. silver-containing precursor and corn syrup) and methanol, determining this ratio would be within the level of ordinary skill in the art through routine experimentation as Setlock teaches that the weight ratios can be adjusted to tailor the pore and grain size (paragraph 0049) and Carredo teaches aperture sizes (i.e. pore size) being related to micron rating and filtration efficiency (paragraph 0046), and one would have had a reasonable expectation of success. However, these references do not teach that the substrate (i.e. the fiberglass) is baked.
In a related field of endeavor, Leonard teaches that a standard bonded fiberglass filter may have possible contamination by surfactants but can be baked at 450-500 °C to remove the resin (i.e. binding material) (Col. 3, lines 1-12). Leonard further teaches that the baked fiberglass filter has shorter flow time than through the bonded filter due to the removal of the resin coating (Col. 4, lines 54-59).
As Carredo teaches a base filter layer, which can be any known air filter or filter material (paragraph 0020), and conventional air filter materials include glass fibers (i.e. fiberglass) (paragraph 0003) and Leonard teaches a fiberglass filter, they are analogous. It would have been obvious to one of ordinary skill in the art before the effective filing date to modify the filter of Setlock-modified, Perera-modified Carredo to include where the fiberglass filter is baked (i.e. by itself) to remove the resin as this can affect the contamination by surfactants and shorten flow time, and one would have had a reasonable expectation of success. It further would have been obvious to bake the fiberglass filter with the precursor infiltrated (i.e. which contains corn syrup as taught by Setlock) as this is considered a duplication of parts (i.e. repeating a step) without producing unexpected results, absent an objective showing. See MPEP § 2144.04(VI)(B).
Claims 7-8: Perera teaches that the metal may be present as a metal, a metal compound, a metal alloy, or combination of these and is preferably selected from one or combination of platinum, titanium, copper, gold, silver, zinc, etc. (paragraph 0053). Suitable compounds include copper oxide, zinc oxide, silver oxide, etc. (paragraph 0054). It would have been obvious to one of ordinary skill in the art before the effective filing date to select the metal as a combination of a metal such as silver and a metal compound such as silver oxide as Perera specifically names these materials as being suitable for an antimicrobial air filter.
Claim 9: Carredo teaches that the porosity, thickness, density, and number of layers of foam air filters can be adjusted to increase efficiency, desired airflow, etc. (paragraph 0048). This is considered to teach that the foam air filters have airflow (i.e. is fluid permeable since air is a fluid). Furthermore, since air passes through all the layers of the air filters (see Figs. 5-7 of Carredo), the substrate as a base filter layer (paragraph 0020) or as a non-copper core plated to form an open-cell copper foam (paragraph 0046) also allows air to pass through (i.e. is fluid permeable).
Claim 14: Carredo teaches a device comprising the air filter (paragraph 0023), where the device may be HVAC/furnace, etc. (paragraph 0050) (i.e. an air filter configured for use in an air filtration system).
Claims 15-17: Carredo teaches the air filter can have a frame or housing (paragraph 0049 and 0059), may be in a range of configurations including being housed in a cartridge (paragraph 0048), can be washable and reusable (paragraph 0064), and may be embodied in a face mask or face portion of a PPE (i.e. personal protection equipment) kit (paragraph 0050). Although Carredo does not use the word “cassette”, the teaching of a cartridge is considered to be interchangeable with the term “cassette” as the instant specification discloses that Figs. 18A and 18B show an example of a facemask having a cassette or cartridge filter (paragraph 0092 of the instant specification).
Claim 23: Leonard teaches that a standard bonded fiberglass filter can be baked at 450-500 °C to remove the resin (i.e. binding material) (Col. 3, lines 1-12). This range overlaps the instantly claimed range and the courts have held that a prima facie case of obviousness exists where claimed ranges overlap, lie inside of, or are close to ranges in the prior art. See MPEP § 2144.05. It is noted that as of the writing of this Office Action, no demonstration of a criticality to the claimed ranges has been presented.
Response to Arguments
Applicant’s arguments, filed 13 April 2026, with respect to the prior art, have been fully considered but are not persuasive for the following reasons:
Applicant argues, see p. 2, that the duplication of parts rationale is erroneous (i.e. baking the fiberglass filter with the precursor infiltration as a duplicate baking step). However, as outlined in the Office Action mailed 12 January 2026, Leonard (i.e. pertaining to the fiberglass filter substrate) teaches that a standard bonded fiberglass filter can be baked at 450-500 °C to remove the resin (i.e. binding material) (Col. 3, lines 1-12) so that the baked fiberglass filter will have a shorter flow time than through the (unbaked) bonded filter due to the removal of the resin coating (Col. 4, lines 54-59), and Setlock (i.e. pertaining to producing a coated or infiltrated substrate) teaches applying a reaction mixture of a metal salt solution with a corn syrup reducing agent to a substrate to produce a coated or infiltrated substrate and heating (paragraph 0004). Setlock does not particularly teach the heating to be baking; however, baking would be considered a conventionally known method of heating (i.e. as a repeated step) that does not produce unexpected results since both the substrate alone and the infiltrated substrate are taught to be heated (i.e. baked), and one would have had a reasonable expectation of success.
Applicant further argues, see p. 2, that none of the references teach that the process of baking by itself and with the precursor infiltrated can adhere the infiltrated substrate to a surface. However, prima facie obviousness is not rebutted by merely recognizing additional advantages or latent properties present but not recognized in the prior art. See MPEP § 2145(II).
Applicant argues, see p. 2-3, that Leonard is non-analogous art because Leonard merely discloses a filter and not a metallic foam. However, the claim recites a filter with a fiberglass substrate, and therefore what is known in the art of a fiberglass filter is reasonably pertinent to the instantly claimed filter even if it does not pertain to every detail of the instantly claimed filter. It is noted that Carredo teaches the use of a conventional glass fiber substrate for an antimicrobial air filter, which further provides motivation to seek what is known in the prior art about conventional fiberglass filter substrates.
Applicant further argues, see p. 3-4, regarding additional teachings by Leonard; however, the teachings of Leonard are cited merely for the teaching that a standard bonded fiberglass filter can be baked at 450-500 °C to remove the resin (i.e. binding material) (Col. 3, lines 1-12) (i.e. what the reference would have suggested to one of ordinary skill in the art) and it is not necessary to bodily incorporate all the features of the secondary reference. See MPEP § 2145(III).
Applicant argues, see p. 4-5, a lack of motivation to bake the substrate of the Setlock-modified, Perera-modified, Carredo filter to remove the resin to shorten flow time and affect the contamination by surfactants because of a different in the type of contamination encountered as disclosed in each of these references compared with that of Leonard. However, this argument pertains to the intended use (i.e. where the filter is to be used which would affect the types of contaminants it would contact). Such function is not a claimed limitation, and the manner of operating the device does not differentiate it from the prior art. See MPEP § 2114. This argument also appears to argue bodily incorporation of additional features of the secondary reference not relied upon. See MPEP § 2145(III).
Applicant argues that there is no indication in the recited references that the filter of Setlock-modified, Perera-modified Carredo would be conductive even though the metallic silver is a known conductive material. Applicant argues that the claim recites that the filter is conductive, not that the metallic foam is conductive. However, the metallic foam being conductive, and being infiltrated within the fiberglass filter substrate (i.e. the metallic foam being made in a substantially identical manner as the instant application based on the disclosure of Setlock as outlined above compared to the instant specification at paragraphs 0067-0068), would render the filter as being conductive. Furthermore, , prima facie obviousness is not rebutted by merely recognizing additional advantages or latent properties present but not recognized in the prior art. See MPEP § 2145(II). As the filter of Setlock-modified, Perera-modified Carredo (further modified by Leonard) is substantially identical materials made in a substantially identical manner as the instantly claimed filter, the instantly claimed property of being conductive is considered to be present because a substantially identical product has substantially identical properties and functions. See MPEP § 2112.01.
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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/KIM S. HORGER/Examiner, Art Unit 1784
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