Degradation-resistant filter media

Abstract

A degradation resistant media composite is provided that can be used in a filter element of long service life. The media composite comprises an efficiency layer polypropylene fibers with electret additive such as a fluoropolymer with fiber sizes in a range 1-5 microns and a basis weight of 20 gsm and 28 gsm. The efficiency layer is laminated to a substrate and can have a scrim on an opposite side for degradation protection.

Description

RBVD Ref. 513552-PCTDEGRADATION-RESISTANT FILTER MEDIACROSS-REFERENCE TO RELATED PATENT APPLICATIONS

[0001] This patent application claims the benefit of U.S. Provisional Patent Application No.63 / 788,535, filed April 14, 2025, and U.S. Provisional Patent Application No. 63 / 756,347, filed February 10, 2025, the entire teachings and disclosure of each of which are incorporated herein by reference thereto.TECHNICAL FIELD

[0002] The present invention relates to an improvement of electrostatic filter media through the use of electrostatically charged materials and / or electret filter medias that are subject to external environment factors for long periods with improved degradation resistance.BACKGROUND

[0003] Electrostatic charged media has been successfully employed in filtration products due to its ability to attract small particles (solid or liquid) ranging from 0.3 pm to 1 pm, achieving high filtration efficiency from MERV 13 to near HEPA levels.

[0004] There are a number of applications for filter media. An alternate to v-bank filters for animal confinement facilities have previously been described. See, for example, U.S. Pat. No.9,510,557 to Crabtree et al. Crabtree discloses a filter media composite with a carrier layer and an efficiency layer, in which the efficiency layer having a higher filtration efficiency than the carrier layer and providing for filtration of PRRSV. The efficiency layer comprise a polymer with a hydrophobic additive (and that the efficiency layer may comprises polypropylene fibers with a fluorine additive with a media example of plasma fluorination).

[0005] Outside of animal confinement, and for “salt fog” filters, electret filter medias are disclosed as in US Patent No. 9,504,945 to Crabtree et al. using similar medias.

[0006] Filters with high dust capacity have also been previously described. See, for example, U.S. Pat. No. 11,198,089. Embossed fluid filter elements have previously been described. See, for example, U.S. Pat. No. 9,314,717. Additionally, hydro charging processes have been employed to increase static charge but exhibit poor degradation resistance due to160115347RBVD Ref. 513552-PCTseveral factors. See, for example, U.S. Pat. Nos. 5,496,507 and 6,397,458, and WO Pub. No.2001 / 091909.

[0007] Generally, there are three primary methods to generate electrostatic charge: triboelectric charging, corona charging, and hydro-charging. The triboelectric charging method involves the physical friction between different polymer fibers (e.g., during the mechanical method of binding fibers together to create a fabric, such as the needle punch process) to generate static charge. The corona charging method involves spunbond webs or melt-blown extruded nonwoven webs that pass through a high-voltage panel to generate static charge. The hydro-charging method introduces electret properties into spunbond webs or melt-blown extruded nonwoven webs by passing them through a water tank, followed by thorough drying. Among these methods, hydro-charging with electrets integrated into the polymers provides superior static charge stability, resulting in significantly slower charge dissipation compared to triboelectric and corona charging. Additionally, the hydro-charging method can achieve much higher filtration efficiency, reaching HEPA grade.

[0008] Currently, for the hydro-charging method, there are two main approaches to incorporate electrets into the polymer (typically polypropylene): additives integrated into a polymer resin and surface treatment. Examples of both is discussed in US Patent No. 6,824,718 to Eitzman et al., which has an example of a web that contained blown polypropylene microfibers with a 1 weight % of a fluorochemical oxazolidinone additive. Eitzman also discloses wetting the web with isopropanol followed by saturation with water to increase charge density. However, Eitzman is directed to an electret filter in the form of a respirator face mask that may be expected to have very limited service life usage as compared to animal confinement filter applications and is directed at different particle / environment concerns.

[0009] To incorporate electrets into the polymer, additives integrated into a polymer resin can be built into the polymer resin or added before fiber extrusion as may be discussed in Eitzman. See also in particular, for example, U.S. Pat. No. 6,397,458. However, this may lead to uneven distribution of electrets throughout the fiber bulk, which can limit effective static charge generation since static charge generation is primarily a surface phenomenon.

[0010] Surface treatment is another way to incorporate electrets into the polymer. This method involves applying electrets to the fiber surface through methods such as plasma260115347RBVD Ref. 513552-PCTtreatment with a fluorine source. See, for example, WO Pub. No. 2001 / 091909 to Ogale. While this method is effective for enhancing static charging ability, this process adds complexity and time after nonwoven fiber extrusion and webbing.

[0011] Both hydro-charging methods can provide high filtration efficiency due to the built-in electrets and they demonstrate greater stability than triboelectric or corona charging.However, many still experience discharge under severe conditions (e.g., 90% of media discharging to 50% after 24 hours of 2-Isopropanol or Isopropyl Alcohol (IPA)vapor conditioning per ISO 16890 testing method).

[0012] Additionally, the hydro-charging media method faces significant risks of weathering degradation for several reasons: its smaller fiber size, the extrusion process, and surface plasma treatment.

[0013] Smaller fibers have a lower denier and have a better surface-to-bulk ratio, enhancing static charge generation and particle attraction (e.g., nanofibers). However, smaller fibers are significantly weaker, especially after dust loading, and their higher surface-to-bulk ratio can lead to increased exposure to light degradation.

[0014] The extrusion process may also cause weathering degradation. Using polymer resin with a higher melt flow index can expedite the extrusion process, resulting in fibers of the same size or denier but with lower or non-uniform crystallinity. While these smaller or poorly crystallized fibers can still achieve high efficiency, they are more susceptible to weathering challenges in application. Even with pre-filters used before high-efficiency final filters, significant weathering degradation is still observed.

[0015] Surface plasma treatment may also cause weathering degradation. This process uses high energy with considerable exposure time, which can pre-damage the polymer before use.

[0016] In addition to current media that provides little weathering degradation protection, known melt-blown media can also exhibit poor degradation resistance due to several factors, including: small diameters, material properties, charging processes, and longevity of use. Regarding small diameters, the high surface-to-bulk ratio of the fibers aids in attracting particles; however, it also contributes to their vulnerability to weathering. Regarding the material properties, polypropylene has lower temperature resistance compared to PET, despite being effective in generating static charge. Regarding the charging processes, some charging360115347RBVD Ref. 513552-PCTmethods, such as plasma treatment, can damage the fibers, impacting their integrity. Lastly, regarding the longevity of use, high-efficiency air filters are typically used for over a year, which presents challenges in maintaining their physical shape and efficiency levels due to degradation.

[0017] Filter media should be pleated with optimized geometry to fully utilize the media’s performance. If there are too few pleats, the media area may result in higher airflow velocity, thereby not fully leveraging the static charge attraction mechanism and failing to meet the desired air filtration efficiency. Conversely, if there are too many pleats, it can cause the pleats to close or squeeze together, reducing airflow and affecting resistance, efficiency, and dust holding capacity. Additionally, the pleat tips may occupy 10-15% of the airflow in the face area, leading to higher resistance.

[0018] Further, proper design of the media layers can optimize performance. Synthetic media is not perfectly straight and firm, especially under airflow pressure, which can result in deviations from the target geometry. Therefore, proper design of the media layers is important to achieving optimized filtration performance, in addition to ensuring the media’s special degradation stability.

[0019] As such, it is believed there is a need for a degradation resistant filter material, which addresses at least some of the drawbacks noted above, such as enhanced degradation stability, greater static charge stability, enhanced resistance to weathering degradation, improved filtration performance, verified layer design, and optimized filter geometry.SUMMARY

[0020] Embodiments of the present invention relate to improving degradation resistance in electret media composites and in particular electret composite filter medias while at the same time maintaining adequate air flow and particle removal efficiencies. Such filter medias may be used in longer service life applications of at least several months, or even at a least a year or multiple years. Such long service life applications include animal confinement such as in US Patent 9,510,557 to Crabtree et al. or may be filter applications in medical, data centers and the like.460115347RBVD Ref. 513552-PCT

[0021] One or more of the following can be used to expand lifespan and avoid fdter media degradation issues: (a) utilize a porous protective cover layer over the efficiency layer on both sides (one of which may be a substrate) (b) replace plasma fluorination with electret additives added to the resin; (c) introducing electret additives in a manner that may cause higher distribution of electret additive near fiber surfaces (d) selecting fibers sizes that are more tightly controlled, preferably between 1 micron and 5 microns that can still provide performance targets (e) selecting electret additives that tend to maintain more permanent charge; (f) utilizing supplement liquid process charging; (g) if hydro-charging, using a lower temperature and higher airflow during the oven drying process, which after liquid application, can help eliminate heating damage to the polypropylene fiber while effectively remove extra water; (h) using pigments in one or more layers (especially protective layer(s)) which have been found to provide improved UV degradation resistance; and / or (i) using in-line high-pressure water spraying onto the fibers immediately after melt-blown extrusion and prior to web formation - in this manner, the web does not need to pass through a water tank to become saturated - instead, each individual fiber is exposed to water via the spray before being deposited in layers, and, consequently, a reduced amount of water must be evaporated, and in some cases oven drying is not required, thereby mitigating or avoiding degradation associated with heating and drying processes.

[0022] By selecting fibers sizes in the efficiency layer that are more tightly controlled (preferably between 1 micron and 5 microns) that can provide filtration performance targets. A few ways to characterize efficiency layer fiber selection: (a) an average fiber diameter of the fibers in the efficiency layer is between 1 and 5 microns; and / or (b) that 95% or greater of the number of fibers of the efficiency layer are between 1 and 5 microns; and / or (c) preferably substantially avoiding and preferably entirely avoiding nanofibers in such efficiency layer because such nanofiber are more easily compromised after longer use intervals (by “substantially avoiding” it is meant that no more than 5% of the number of fibers are nanofibers).

[0023] Accordingly, a degradation resistant filter material with additives is provided with enhanced degradation stability, greater static charge stability, enhanced resistance to560115347RBVD Ref. 513552-PCTweathering degradation, improved filtration performance, verified layer design, and optimized filter geometry.

[0024] The present degradation resistant filter media successfully enhances weathering degradation and static charge stability by utilizing a specific grade and denier, along with targeted additives. A denier is a unit of measurement used to determine thickness of yarn, thread, or fabric, such as polypropylene. The present degradation resistant filter media maintains an initial filtration efficiency as high as MERV 16 after different samples are subjected to different tests, respectively: IPA vapor discharging (per ISO 16890); Potassium Chloride (KC1) conditioning (per ASHRAE 52.2 Appendix J); MIL-STD-810G Method 505.6 Procedure II degradation test.

[0025] The filter elements and methods preferably avoid less desirable techniques such as plasma treatment and instead utilize an improved hydro-charging process with additives containing electrets added before fiber extrusion. Once the fiber is extruded, the extruded web then passes through a water bath and is fully dried. This method specifies a particular range of fiber denier, additive type, and volume to ensure high efficiency and airflow while significantly improving static charge stability. In one embodiment this has been found to be less than 5% reduction for 0.3 pm particles with post-IPA vapor, with enhanced resistance to weathering degradation.

[0026] The degradation resistant filter media also offers various lamination methods with substrate and scrim layers (plain or colored) for additional protection of the melt-blown fiber. Furthermore, it provides specific filters constructed with the aforementioned media, resulting in optimized filtration performance.

[0027] At least one embodiment provides a high efficiency synthetic filter (MERV13-near HEPA) made from polypropylene melt-blown laminated media. The extrusion using polypropylene can create fine fibers down to the micrometer. Additionally, processes such as hydro charging can be employed to increase static charge, which helps attract small particles in the air, making it suitable for applications like N95 face masks and high-efficiency air filtration filters.660115347RBVD Ref. 513552-PCT

[0028] Some of the inventive aspects as defined by some of the independent claims relate to a laminated media, melt-blown layers, or other such filter elements to create a degradation resistant filter media.

[0029] For example, a melt-blown layer may be created by mixing a melt-blown thermoplastic with additives, extruding the material, rinsing it with a liquid, drying it, then laminating it with an adhesive material to join it with at least one other layer to create the degradation resistant filter media.

[0030] In this example and / or another example, a filter media may include a hydro-charged melt-blown thermoplastic with additives that is bonded to at least one layer to create the degradation resistant filter media.

[0031] Various advantages and additional inventive features may flow from this filter layer methodology. This methodology is particularly advantageous for improving electrostatic filter media because the materials combined with specific additives and layers provides a degradation resistant filter media that is believed more efficient than those on the market.

[0032] According to one inventive aspect, the degradation resistant filter media provides a laminated media having a hydro-charged polypropylene melt-blown layer with additives, where the layer has a first side and a second side, a polyester substrate layer, where the melt blown layer is laminated with an adhesive and adhered to at least part of the polyester substrate layer first side of the melt-blown layer, and a scrim layer, where the scrim layer is applied to at least part of the second side of the melt-blown layer.

[0033] The laminated media additive may include one or more of the following: polypropylene, polytetrafluoroethylene, pigment, substance with electrets, plastic, polymer, corrosion resistant material, thermally stable material, natural substance, and synthetic substance. The additive may be made of one or more substances or materials. It may also be a combination. This list is not exhaustive, similar materials with similar properties may be utilized. Additives are used prior to the extruding but may also be utilized after. Additives may be added at multiple points during the process.

[0034] The laminated media adhesive may be a hot melt glue or a sonic bonding. Further, the substrate layer may have a weight of between 40 gsm and 100 gsm. The substrate layer may760115347RBVD Ref. 513552-PCThave pigments. The laminated media scrim layer may be between 5 gsm and 20 gsm. Further, the laminated media scrim layer may include pigments.

[0035] In some embodiments, the laminated media is pleated. Further, the pleats may have a height of between 1 inch and 16 inches. The pleats may have a pleat-to-pleat spacing of between 2 mm to 22 mm. In further embodiments, the laminated media is pleated using embossed pleating technology. Hot melt glue lines may be applied between pleats. In some embodiments, either hot melt or polyurethane potting may be used for assembly. In some embodiments, the laminated media may further comprise a plastic or metal frame where the laminated media is placed within the frame.

[0036] According to another inventive aspect, the degradation resistant filter media provides a laminated media comprising a hydro-charged melt-blown thermoplastic with additives and a material, were the melt-blown thermoplastic is bonded to the material. The thermoplastic may be polypropylene. In some embodiments, the additive composition includes 20% polytetrafluoroethylene (PTFE) and 80% polypropylene. The material may be a polyester substrate. The material and melt-blown thermoplastic may be bonded with between 1 gsm and 3 gsm hot melt adhesive. The melt-blown thermoplastic may be at least 22 gsm and the material may be at least 70 gms.

[0037] According to another inventive aspect, the degradation resistant filter media provides a method of creating a degradation-resistant filter material comprising the steps of extruding a melt-blown thermoplastic with additives, then rinsing the extruded thermoplastic with a liquid, then drying the rinsed extruded thermoplastic, and then laminating the dried thermoplastic with an adhesive to at least one layer.

[0038] In some embodiments, the method thermoplastic may be polypropylene. The thermoplastic may be 22 gsm. The melt-blown thermoplastic may be extruded with 5% additives. The additive may comprise 20% polytetrafluoroethylene (PTFE) and 80% polypropylene. The melt-blown thermoplastic may have a melt flow index of 1200. The extruded fiber may have a diameter of between 1.2 pm and 4.8 pm. The liquid may be water. The dried thermoplastic may be laminated with between 1 gsm and 3 gsm of an adhesive. The at least one layer may be a polyester substrate.860115347RBVD Ref. 513552-PCT

[0039] According to another inventive aspect, the degradation resistant filter media provides a method of creating a melt-blown layer, comprising mixing polypropylene with between 1% and 10% additives, where the additives contains of between 10% and 50% polytetrafluoroethylene (PTFE), then melt-blow extruding the mixture, where the extruded mixture has a diameter of between 2pm and 5 pm, then passing the extruded mixture through at least one liquid tank, then drying the mixture.

[0040] In some embodiments, the liquid in the liquid tank is water within the method of creating a melt-blown layer. The polypropylene may be mixed with 5% additives. The additive may contain 20% PTFE.

[0041] According to another inventive aspect, the degradation resistant filter media provides a melt-blown layer, comprising a polypropylene material and additives, where the additives comprise of between 10% and 50% PTFE, where the additives are mixed before melt-blown extrusion, further where the extruded fiber diameter preferably ranges between 1 pm and 5 pm (however, in some embodiments nanofibers may be formed and included in which fiber diameter may range more broadly between 0.1 pm and 5 pm), and where the extruded media passes through at least one liquid tank and a complete drying process.

[0042] As such, it is believed the subject invention addresses at least some of the drawbacks noted above and provides enhanced degradation stability, greater static charge stability, enhanced resistance to weathering degradation, improved filtration performance, verified layer design, and optimized filter geometry.

[0043] Accordingly, more details aspects and embodiments of this disclosure are described in the following numbered clauses.

[0044] 1. A media composite, comprising: an efficiency layer having a basis weight of between 20 gsm and 28 gsm and comprising fibers with a static charge, the fibers having an average fiber diameter ranging between 1.2 pm and 4.8 pm, the fibers comprising a polypropylene material and an electret additive incorporated in the polypropylene material; a substrate layer supporting the efficiency layer, the substrate layer being porous and laminated to the efficiency layer; and wherein the media composite provides an initial filtration efficiency of at least a MERV 13, when used in a filter element.960115347RBVD Ref. 513552-PCT

[0045] 2. The media composite of clause 1, wherein the efficiency layer has a caliper thickness of between 0.1 mm and 0.4 millimeter, wherein the efficiency layer exhibits an initial air flow permeability of between 30 and 60 CFM @ 125Pa, and wherein 95% of the number of fibers of the efficiency layer have fiber diameter between 1 and 5 microns.

[0046] 3 The media composite of any of clauses 1-2, wherein the efficiency layer is provided with additional process charge, preferably a hydro-charge.

[0047] 4. The media composite of any of clauses 1-3, wherein the media composite provides an initial filtration efficiency of at least a MERV 16, when used in a filter element.

[0048] 5. The media composite of any of clauses 1-4, wherein the media composite can maintain an initial filtration efficiency of at least a MERV 16 when used in a filter element and tested by at least one of the following degradation tests: (a) IPA vapor discharging (per ISO 16890 - 2022); (b) KC1 conditioning (per ASHRAE 52.2 - 2017 Appendix J); and (c) MIL-STD-810G Method 505.6 Procedure II degradation test - 2022.

[0049] 6. The media composite of clause 5, wherein the media composite can maintain an initial filtration efficiency of at least a MERV 16 when used in a filter element, when separate samples thereof are tested by all three of said degradation tests.

[0050] 7. The media composite of any of clause 1-6, wherein an electret additive comprises fluorine, preferably a per- and / or polyfluoroalkyl substance.

[0051] 8 The media composite of any of clauses 1-7, wherein the electret additive comprises a fluoropolymer, preferably polytetrafluoroethylene (PTFE).

[0052] 9. The media composite of any of clause 1-8, wherein the electret additive comprises a mixture of polypropylene and the fluoropolymer, by weight, between 50 % and 90% polypropylene and between 10 % and 50 % fluoropolymer, and wherein the electret additive is preferably unevenly distributed with a base portion of the polypropylene material.

[0053] 10. The media composite of any of clauses 1-9, wherein the fibers of the efficiency layer comprise between 1% and 5% fluoropolymer in the fibers, by weight of the fibers, and wherein the fibers of the efficiency layer comprise between 95% and 99% of polypropylene, by weight of the fibers.

[0054] 11. The media composite of any of clauses 1-10, wherein the fibers of the efficiency layer further comprise one more additive(s) selected from the following group: silica,1060115347RBVD Ref. 513552-PCTtourmaline, zirconium carbonate, calcium carbonate, polyvinylamine, anionic polyacrylamide, oxidized polyethylene wax, volcanic stone powder.

[0055] 12. The media composite of any of clauses 1-11, wherein the fibers of the efficiency layer having an average fiber diameter ranging between 1.2 pm and 3.0 pm, preferably between 1.5 pm and 2.5 pm.

[0056] 13. The media composite of any of clauses 1-12, wherein the negative static charge is at least -0.06 kV, and preferably approximately -0.06 to -0.2 kV.

[0057] 14. The media composite of any of clauses 1-13, wherein the fibers of the efficiency layer comprise melt-blown fibers, spun-bond fibers, force-spun fibers, and / or needle-punch fibers; and preferably are entirely melt-blown fibers.

[0058] 15. The media composite of any of clauses 1-14, wherein the substrate comprises fibers of polyester, polypropylene, polyethylene, Nylon, and / or fiberglass, and preferably the fibers of the substrate are entirely polyester; and wherein the substrate has a basis weight of between 50 gsm and 100 gsm.

[0059] 16. The media composite of clause 8, wherein the substrate comprises: (a) an initial air flow permeability of greater than 100 CFM and more preferably between 500 and 120 CFM @ 125Pa, (b) a caliper thickness of between 0.3 mm and 0.6 mm, (c) wherein the fibers of the substrate comprises an average fiber diameter of between 10 pm and 40 pm; (d) a MERV rating by itself of no greater than MERV 11 and more preferably less than MERV 8; (e) optionally includes pigments; and (f) wherein the composite media has an initial air flow permeability of between 30 and 60 CFM @ 125Pa, and a caliper thickness of between 0.4 mm and 1.3 mm.

[0060] 17. The media composite of any of clauses 1-16, further comprising an adhesive facilitating said laminating comprising a glue, thermal bonding or sonic bonding, that is preferably a laminating glue of between 1 gsm amd 3 gsm that is applied between the melt-blown media and the substrate.

[0061] 18. The media composite of any of clauses 1-17, further comprising a porous protective layer laminated to the efficiency layer on a side of the opposite of the substrate layer.

[0062] 19. The media composite of clause 18, wherein the porous protective layer comprises a fibrous scrim.1160115347RBVD Ref. 513552-PCT

[0063] 20. The media composite of any of clauses 18-19, wherein the porous protective layer comprises fibers of polyester, polypropylene, polyethylene, Nylon, and / or fiberglass, and preferably the fibers of the protective layer are entirely polyester; and wherein the substrate has a basis weight of between 5 gsm and 20 gsm.

[0064] 21. The media composite of any of clauses 18-19, wherein the porous protective layer us preferably a scrim, and comprises: (a) an initial air flow permeability of greater than 100 CFM and more preferably between 1000 and 2000 CFM @ 125Pa, (b) a caliper thickness of between 0.1 mm and 0.3 mm, (c) wherein the fibers of the porous protect layer comprises an average fiber diameter of between 10 pm and 40 pm; (d) a MERV rating by itself of no greater than MERV 11 and more preferably less than MERV 5; € optionally includes pigments; and wherein the composite media has an initial air flow permeability of between 30 and 60 CFM @ 125Pa, and a caliper thickness of between 0.4 mm and 1.3 mm.

[0065] 22. The media composite of any of clauses 1-21, wherein the media composite is pleated into pleated filter media with pleats, that preferably have a height of between 1 inch and 16 inches, and preferably have a pleat-to-pleat spacing of between 2 mm and 22 mm.

[0066] 23. The media composite as in clause 22, wherein pleated filter media further comprises embossments formed into pleat panels between scored pleat tips of the pleats, and preferably adhesive beads are applied between pleats stabilizing the pleats.

[0067] 24. A filter element comprising the media composite of any of clauses 1-23, comprising a frame defining a central cavity, with the media composite placed into the cavity and sealed to the frame to prevent unfiltered air flow from an inlet side to an outlet side.

[0068] 25. A filter element comprising: a media composite providing the filter element with at least a MERV 14 rating, comprising: (a) an efficiency layer comprising an electret filter media; (b) a substrate layer supporting the efficiency layer, the substrate layer being porous and laminated to the efficiency layer; and (c) a porous protective layer arranged on a side of the efficiency layer opposite of the substrate layer; and a frame defining a central cavity, with the media composite placed into the cavity and sealed to the frame to prevent unfiltered air flow from an inlet side to an outlet side.

[0069] 26. The filter element of clause 25, wherein the efficiency layer having a basis weight of between 20 gsm and 28 gsm and comprising fibers with a static charge, the fibers1260115347RBVD Ref. 513552-PCThaving an average fiber diameter ranging between 1.2 gm and 4.8 gm, the fibers comprising a polypropylene material and an electret additive incorporated in the polypropylene material;

[0070] 27. The filter element of any of clauses 25-26, wherein the efficiency layer has a caliper thickness of between 0.1 mm and 0.4 millimeter, wherein the efficiency layer exhibits an initial air flow permeability of between 30 and 60 CFM @ 125Pa, and wherein 95% of the number of fibers of the efficiency layer have fiber diameter between 1 and 5 microns.

[0071] 28. The filter element of any of clauses 25-27, wherein the efficiency layer is provided with additional process charge, preferably a hydro-charge.

[0072] 29. The filter element of any of clauses 25-28, wherein the filter element has an initial filtration efficiency of at least a MERV 16.

[0073] 30. The filter element of any of clauses 25-29, wherein the filter element can maintain an initial filtration efficiency of at least a MERV 16 tested by at least one of the following degradation tests: (a) IPA vapor discharging (per ISO 16890 - 2022); (b) KC1 conditioning (per ASHRAE 52.2 - 2017 Appendix J); and (c) MIL-STD-810G Method 505.6 Procedure II degradation test - 2022.

[0074] 31 The filter element of any of clauses 25-30, wherein the filter element can maintain an initial filtration efficiency of at least a MERV 16, when separate filter elements thereof are tested by all three of said degradation tests.

[0075] 32 The filter element of any of clauses 25-31, wherein an electret additive comprises fluorine, preferably a per- and / or polyfluoroalkyl substance.

[0076] 33. The filter element of any of clauses 25-32, wherein the electret additive comprises a fluoropolymer, preferably polytetrafluoroethylene (PTFE).

[0077] 34 The filter element of any of clauses 25-33, wherein the electret additive comprises a mixture of polypropylene and the fluoropolymer, by weight, between 50 % and 90 % polypropylene and between 10 % and 50 % fluoropolymer, and wherein the electret additive is preferably unevenly distributed with a base portion of the polypropylene material.

[0078] 35. The filter element of any of clauses 25-34, wherein the fibers of the efficiency layer comprise between 1 % and 5 % fluoropolymer in the fibers, by weight of the fibers, and wherein the fibers of the efficiency layer comprise between 95 % and 99 % of polypropylene, by weight of the fibers.1360115347RBVD Ref. 513552-PCT

[0079] 36. The filter element of any of clauses 25-35, wherein the fibers of the efficiency layer further comprise one more additive(s) selected from the following group: silica, tourmaline, zirconium carbonate, calcium carbonate, polyvinylamine, anionic polyacrylamide, oxidized polyethylene wax, volcanic stone powder.

[0080] 37. The filter element of any of clauses 25-36, wherein the fibers of the efficiency layer having an average fiber diameter ranging between 1.2 pm and 3.0 pm, preferably between 1.5 pm and 2.5 pm.

[0081] 38. The filter element of any of clauses 25-37, wherein the negative static charge is at least -0.06 kV, and preferably approximately -0.06 to -0.2 kV.

[0082] 39. The filter element of any of clauses 25-38, wherein the fibers of the efficiency layer comprise melt-blown fibers, spun-bond fibers, force-spun fibers, and / or needle-punch fibers; and preferably are entirely melt-blown fibers.

[0083] 40. The filter element of any of clauses 25-39, wherein the substrate comprises fibers of polyester, polypropylene, polyethylene, Nylon, and / or fiberglass, and preferably the fibers of the substrate are entirely polyester; and wherein the substrate has a basis weight of between 50 gsm and 100 gsm.

[0084] 41. The filter element of any of clauses 25-40, wherein the substrate comprises: (a) an initial air flow permeability of greater than 100 CFM and more preferably between 500 and 120 CFM @ 125Pa, (b) a caliper thickness of between 0.3 mm and 0.6 mm, (c) wherein the fibers of the substrate comprises an average fiber diameter of between 10 pm and 40 pm; (d) a MERV rating by itself of no greater than MERV 11 and more preferably less than MERV 8; (e) optionally includes pigments; and wherein the composite media has an initial air flow permeability of between 30 and 60 CFM @ 125Pa, and a caliper thickness of between 0.4 mm and 1.3 mm.

[0085] 42. The filter element of any of clauses 25-41, further comprising an adhesive facilitating said laminating comprising a glue, thermal bonding or sonic bonding, that is preferably a laminating glue of between 1 gsm amd 3 gsm that is applied between the melt-blown media and the substrate.

[0086] 43. The filter element of any of clauses 25-42, wherein the porous protective layer comprises a fibrous scrim.1460115347RBVD Ref. 513552-PCT

[0087] 44. The filter element of any of clauses 25-43, wherein the porous protective layer comprises fibers of polyester, polypropylene, polyethylene, Nylon, and / or fiberglass, and preferably the fibers of the protective layer are entirely polyester; and wherein the substrate has a basis weight of between 5 gsm and 20 gsm.

[0088] 45. The filter element of any of clauses 25-44, wherein the porous protective layer us preferably a scrim, and comprises: (a) an initial air flow permeability of greater than 100 CFM and more preferably between 1000 and 2000 CFM @ 125Pa, (b) a caliper thickness of between 0.1 mm and 0.3 mm, (c) wherein the fibers of the porous protect layer comprises an average fiber diameter of between 10 pm and 40 pm; (d) a MERV rating by itself of no greater than MERV 11 and more preferably less than MERV 5, (e) optionally includes pigments; and wherein the composite media has an initial air flow permeability of between 30 and 60 CFM @ 125Pa, and a caliper thickness of between 0.4 mm and 1.3 mm.

[0089] 46. The filter element of any of clauses 25-45, wherein the media composite is pleated into pleated filter media with pleats, that preferably have a height of between 1 inch and 16 inches, and preferably have a pleat-to-pleat spacing of between 2 mm and 22 mm.

[0090] 47. The filter element of any of clauses 25-46, wherein pleated filter media further comprises embossments formed into pleat panels between scored pleat tips of the pleats, and preferably adhesive beads are applied between pleats stabilizing the pleats.

[0091] 48. A method of using of the filter element according to any of clauses 25-47 in an animal confinement building containing livestock.

[0092] 49. The method of clause 48, further comprising using the filter element with a prefilter arranged proximate the filter element.

[0093] 50. The method of clause 48, further comprising arranging a first stage of first stage prefilters upstream of said filter element with said prefilter, the first stage being spaced from said filter element with said prefilter by a service walkway.

[0094] 51. A method of making a filter media, comprising: mixing polypropylene material with an electret additive to create an electret polymer mixture; extruding the electret polymer into a porous efficiency web layer having a basis weight of between 20 gsm and 28 gsm and comprising fibers with a static charge, the fibers having an average fiber diameter ranging between 1.2 pm and 4.8 pm; and process charging the efficiency web layer.1560115347RBVD Ref. 513552-PCT

[0095] 52. The method of clause 51, wherein the process charging comprises hydrocharging with a liquid comprising water with active drying thereafter, wherein the hydrocharging preferably comprising high-pressure spraying or dipping.

[0096] 53. The method of clause 52, wherein the hydro-charging comprises using a wetting agent in solution with water, with additional water rinsing, the wetting agent preferably comprising potassium chloride or an alcohol.

[0097] 54. The method of any of clauses 51-53, wherein the extruding comprises meltblowing, and wherein the electret additive comprises fluorine, preferably a per- and / or polyfluoroalkyl substance.

[0098] 55. The method of clause 54, wherein the electret additive comprises a fluoropolymer, preferably polytetrafluoroethylene (PTFE).

[0099] 56. The method of clause 55, wherein the electret additive comprises an electret additive mixture of polypropylene and the fluoropolymer, by weight, between 50 % and 90 % polypropylene and between 10 % and 50 % fluoropolymer, and wherein the method comprises: providing a first batch comprising polypropylene; providing a second batch of the combination additive mixture; and introducing the second batch with the first batch to provide the an electret polymer mixture with an amount of polypropylene that is between 90%-99% by weight and an amount of the fluoropolymer that is between 1%-10% by weight, more preferably between 1% and 5%.

[0100] 57. The method of any of clauses 51-56, further comprising laminating the efficiency web layer to a substrate layer to provide a media composite, wherein the substrate comprises: (a) an initial air flow permeability of greater than 100 CFM and more preferably between 500 and 120 CFM @ 125Pa, (b) a caliper thickness of between 0.3 mm and 0.6 mm, (c) wherein the fibers of the substrate comprises an average fiber diameter of between 10 pm and 40 pm; (d) a MERV rating by itself of no greater than MERV 11 and more preferably less than MERV 8; (e) optionally includes pigments; and wherein the composite media has an initial air flow permeability of between 30 and 60 CFM @ 125Pa, and a caliper thickness of between 0.4 mm and 1.3 mm.

[0101] The method of any of clauses 57, further comprising laminating the efficiency web layer to a porous protective layer that is preferably a scrim, wherein the porous protective layer1660115347RBVD Ref. 513552-PCTcomprises: (a) an initial air flow permeability of greater than 100 CFM and more preferably between 1000 and 2000 CFM @ 125Pa, (b) a caliper thickness of between 0.1 mm and 0.3 mm, (c) wherein the fibers of the porous protect layer comprises an average fiber diameter of between 10 pm and 40 pm; (d) a MERV rating by itself of no greater than MERV 11 and more preferably less than MERV 5; and (e) optionally includes pigments.

[0102] 59. The method of any of clauses 51-58, wherein the media composite can maintain an initial filtration efficiency of at least a MERV 16 when used in a filter element.

[0103] 60. The method of clause 59, wherein the media composite can maintain an initial filtration efficiency of at least a MERV 16 when used in a filter element, when tested by at least one of the following degradation tests: (a) IPA vapor discharging (per ISO 16890 - 2022); (b) KC1 conditioning (per ASHRAE 52.2 - 2017 Appendix J); and (c) MIL-STD-810G Method 505.6 Procedure II degradation test - 2022; and wherein preferably the media composite can maintain an initial filtration efficiency of at least a MERV 16, when separate samples thereof are tested by all three of said degradation tests.

[0104] The method of any of clauses 51-60, wherein the efficiency layer has a caliper thickness of between 0.1 mm and 0.4 millimeter, wherein the efficiency layer exhibits an initial air flow permeability of between 30 and 60 CFM @ 125Pa, and wherein 95% of the number of fibers of the porous efficiency web layer have fiber diameter between 1 and 5 microns.BRIEF DESCRIPTION OF THE DRAWINGS

[0105] The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the degradation resistant filter media and, together with the description, serve to explain the principles of the invention. In the drawings:

[0106] FIG. 1 is an exploded assembly view of a laminated media such as in Example 1 with hydro-charged PP melt blown with electret additive, and polyester substrate;

[0107] FIG. 2 is an exploded assembly view of a laminated media such as in Example 2 with scrim white (no-pigment), hydro-charged PP melt blown with electret additive, and polyester substrate;1760115347RBVD Ref. 513552-PCT

[0108] FIG. 3 is an exploded assembly view of a laminated media such as in Example 3 with scrim pigment colored, hydro-charged PP melt blown with electret additive, and polyester substrate;

[0109] FIGS. 4A, 4B, 4C are SEM photo images of the efficiency layer of a Degradation Resistant Filter Media Sample Fiber Size of Sample Area #1 - Magnified at lOOOx, 5000x, and lOOOOx respectively for the efficiency layer of FIGS. 1-3 also showing fiber measurements at intermediate locations between fiber contact / bond points that can be used for determining fiber size measurements;

[0110] FIGS. 5A, 5B, 5C are SEM photo images of the efficiency layer of a Degradation Resistant Filter Media Sample Fiber Size of Sample Area #2 - Magnified at lOOOx, 5000x, and lOOOOx respectively for the efficiency layer of FIGS. 1-3 also showing fiber measurements at intermediate locations between fiber contact / bond points that can be used for determining fiber size measurements;[OHl] FIGS. 6A, 6B, 6C are SEM photo images of the efficiency layer of a Degradation Resistant Filter Media Sample Fiber Size of Sample Area #3 - Magnified at lOOOx, 5000x, and lOOOOx respectively for the efficiency layer of FIGS. 1-3 also showing fiber measurements at intermediate locations between fiber contact / bond points that can be used for determining fiber size measurements;

[0112] FIG. 7 is a chart detailing filter efficiency tested before and after 24 hours IPA vapor per ISO 16890 standard conditioning method (Sample 2 is made with Degradation Resistant Media without scrim layer (FIG. 1); sample 12 is made with Degradation Resistant Media with scrim layer (un-pigmented - FIG. 2); and sample 13 is made with Degradation Resistant Media with green pigment scrim layer (FIG. 3); with all three showed significant better efficiency stability than the regular MERV16 media. The sample #7, #8, and #15 also used additives but not as effective as the present Degradation Resistant Media, additionally, its weathering degradation is poor as shown on some comparative medias (other than sample 2) on the left of FIG. 7);

[0113] FIG. 8 is an isometric view of an embodiment of a deep pleat filter element in accordance with an embodiment of the present invention incorporating the improved filtration media of any of FIG. 1-7 and / or as described herein, which can be employed in the systems and1860115347RBVD Ref. 513552-PCThousings of an animal confinement filtration application such as shown in U.S. Patent No. 9,510,557 to Crabtree et. al, which is incorporated by reference in its entirety;

[0114] FIG. 9 is a cross section of a portion of the filter element shown in FIG. 8;

[0115] FIG. 10 is an enlarged schematic plan view of two pleats along either upstream or downstream face of the pleat filter pack used in the filter element of FIGS. 8 and / or 9 to better illustrate integral embossments in the pleat flanks and bead spacers and supports that made be interposed between adjacent pleat flanks;

[0116] FIG. 11 is a schematic illustration of the synthetic filter media employed in the filter pack of FIG. 8 showing a carrier substrate layer and a high efficiency hydrophobic layer as om FIG. 1. and also optionally a protective cover layer on a side opposite the substrate layer (as in FIGS. 2 or 3);

[0117] FIG. 12 is a schematic demonstrative illustration of an embodiment of a melt-blow apparatus and method for forming the efficiency layer for the electret filter media which is used / shown in FIGS. 1-11;

[0118] FIG. 13 is a schematic demonstrative illustration of an embodiment of a process charging apparatus and method for hydro charging using a multi-tank liquid application and drier for the efficiency layer as may be produced in FIG. 12 or otherwise for the efficiency layer according to FIGS. 1-11;

[0119] FIG. 14 is a schematic demonstrative illustration of an alternative embodiment to that of FIG. 13 of a process charging apparatus and method for hydro charging using a high pressure water sprayer and drier for the efficiency layer as may be produced in FIG. 12 or otherwise for the efficiency layer according to FIGS. 1-11;

[0120] FIG. 15 is a schematic demonstrative illustration of a lamination apparatus and method for laminating the efficiency layer electret to a substrate layer in accordance with an embodiment and for example the media of FIG. 1;

[0121] FIG. 16 is a schematic demonstrative illustration of a lamination apparatus and method for laminating the efficiency layer electret to a substrate layer in accordance with another embodiment similar to that of FIG. 15 but also with lamination provide for a protective layer and for example the medias of FIGS. 2-3 and 11.1960115347RBVD Ref. 513552-PCT

[0122] FIG. 17 is an SEM photo image of a cross-section the composite media of the Degradation Resistant Filter Media, for example according to the construction of FIG. 2 and FIG. 11.

[0123] While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims.DETAILED DESCRIPTION

[0124] FIGS. 1-3 illustrate media composites 10, 10A, 10B according to embodiments of the present invention. Each media composite media composite 10, 10A, 10B comprises at least a porous efficiency layer, which is illustrated as a hydro-charged polypropylene layer 12, that is laminated to a porous substrate layer, illustrated as a polyester substrate 14.

[0125] As will be discussed below, additional media degradation enhancements are provided in the media composite 10, 10A, 10B which can be in the fiber / size / material formulation and charging of the efficiency layer 12 (as discussed in greater herein above and later-on), and / or the provision of a protective layer to protect a side (typically the upstream inlet side) from UV exposure from sunlight and / or other such external degradation concerns.

[0126] Slight variations are shown in FIGS. 1-3, in that in the FIG. 1 embodiment no protective cover layer is employed in the composite media 12 This may be used in applications that are not subject to certain situations such as exposed sunlight as when may be covered by a prefilter as per applications according to U.S. Pat. No. 9,510,557 to Crabtree et al. or other such applications.

[0127] More preferably, and as shown in FIGS. 2-3, the composite media 10 A, 10B additionally comprises a porous protective cover layer laminated to a side of the polypropylene layer 12 opposite of the polyester layer 12. This porous protective cover layer is shown as a scrim 16A, 16B, respectively. The scrims are the same, other than scrim 16B includes fibers that have pigment added that can increase UV resistance, whereas scrim 16A has no added pigment. Such embodiments of FIGS. 2-3 may also be used such applications subject to2060115347RBVD Ref. 513552-PCTupstream / extemal protections, for example even if used in filtration housing system that is used in conjunction with an upstream prefilter.

[0128] The protective cover layer provided by scrims 16A and 16B preferably are on the upstream inlet side of the efficiency layer provided by polypropylene layer 12 with the substrate layer provided by polyester layer 14 on the downstream outlet side. Alternatively, that may be reversed, with such substrate layer on the upstream inlet side of the efficiency layer, and the protective cover layer on the downstream outlet side.

[0129] The protective cover layer such as provided by scrims 16A, 16B may improve existing electret medias in embodiments herein such as described according to U.S. Pat. No.9,510,557 to Crabtree et al. or other such electret medias discussed in the background section. As such, according to some broader aspects, an electret filter media is provided may have MERV rating of at least 14 and more preferably at least a MERV 16, that is relatively open to air flow and permeable with an air flow, which include synthetic fibers and preferably melt blown (and / or electrospun in alternative embodiments) provide for heat setting, high permeability and efficiency.

[0130] In some embodiments, one or more efficiency layers are laminated to a synthetic carrier layer. As per ‘557 patent to Crabtree, example materials may be polypropylene and polyester, however nylon, pvc or other polymers may be selected, including fluoropolymers and fluororesins. The filter media is preferably an electret. In some embodiments, a hydrophobic additive such as fluorine is added to the polymer by plasma fluorination such as described in Ogale, U.S. Pat. No. 6,419,871, the entire disclosure of which is hereby incorporated by reference. Other fluorination and additives that may be alternatively added are described in Rousseau et al., U.S. Pat. No. 5,908,598 and Eitzman et al., U.S. Pat. No.6,406,657. The fluorination of the media (addition of fluorine atoms into the polymer) can create a hydrophobic property.

[0131] However, as discussed herein, more preferably, an improved efficiency layer in the form of the polypropylene layer 12 is provided that has selected electret additive and / or efficiency fiber / layer size / weight properties, which provide degradation resistance enhancements that can be used alone or more preferably in conjunction with each other. For example, using these features in combination, can provide good air flow permeability (thereby2160115347RBVD Ref. 513552-PCTavoiding high pressure drop), and at the same time provide high particular capture efficiencies and MERV rating.

[0132] PP Fibers, Electret Additive Selection & Charge

[0133] As to the first point, in embodiments, plasma fluorination for an electret additive may not be utilized. Instead, more degradation enhancements are provided with an electret additive 20 added to polypropylene material 22 for the fibers 18 (FIGS. 4-6 and 12) of the efficiency layer 12, preferably prior to fiber formation (e.g., typically by extrusion, such as melt-blowing as is most preferred).

[0134] The electret additive 20 can comprise fluorine, preferably a per- and / or polyfluoroalkyl substance. That is most preferred as being able to hold a more permanent charge. However, other electret additives may additionally, or alternative used such as silicon based electrets (see table below), and other electret substances, especially those that are subject to holding more permanent charge.

[0135] In the fibers shown in FIGS. 4-6, the electret additive 20 comprises a fluoropolymer, and in particular polytetrafluoroethylene (PTFE). By already being in a polymer the introduction facilitates easier processing and fewer steps, while also providing the degradation resistance advantages over other techniques as noted above.

[0136] Such electret additive 20 can be evenly distributed in polymer mixture in the fiber structure or more advantageous unevenly distributed in the fibers 18 such as with more electret additive 20 closer to the fiber surface. To accomplish uneven distribution that may result in more electret additive 20 closer to the fiber surface and / or to better ensure proper dosing, the electret additive 20 can be added downstream in the fiber form process as shown in FIG. 12 (alternatively, such electret additive 20 could be simply mixed with base polypropylene material 22 resulting in even distribution).

[0137] The electret additive 20 can comprise a mixture of polypropylene and the fluoropolymer, by weight, between 50 % and 90 % polypropylene and between 10 % and 50 % fluoropolymer.

[0138] Regardless of whether separate introduction and staging is used for electret additive 20 as in FIG. 12, the resulting fibers 18 of the efficiency layer comprise between 1 % and 5 %2260115347RBVD Ref. 513552-PCTfluoropolymer in the fibers, by weight of the fibers, and wherein the fibers of the efficiency layer comprise between 95 % and 99 % of polypropylene, by weight of the fibers. Also, preferably, the efficiency layer is provided with additional process charge, preferably a hydrocharge (embodiment options for example in FIGS. 13 or 14). Such hydro-charging works in conjunction with the electret additive, to further enhance static charge which have been found to increase particle efficiency capture.

[0139] Other charging techniques such as corona charging could be used, however, those are not expected to be long lasting and result in degradation improvements discussed herein.

[0140] The static charge for the efficiency layer developed with electret additive and process charge at least -0.06 kV, and preferably approximately -0.06 to -0.2 kV

[0141] Fiber Size and / or Layer Parameter Selection

[0142] As to the second point, in embodiments, the efficiency layer (e.g., polypropylene layer 12) the fibers 18 have been selected to improve degradation and media longevity during use by generally avoiding too small of fibers and generally avoiding too large of fibers; thereby providing sufficient basis weight to achieve air flow capacity, particular capture capacity for extended service life and while having at least comparable particle capture efficiencies especially over service life.

[0143] For example, in an embodiment, the polypropylene layer 12 has a basis weight of between 20 gsm and 28 gsm and its fibers 18 and have an average fiber diameter ranging between 1 and 5 microns (for example between 1.2 pm and 4.8 pm).

[0144] Also, for example, as to fiber variability, preferably, 95% of the number of fibers have fiber diameter between 1 and 5 microns (for example, may be particularly between 1.2 pm and 4.8 pm, more preferably between 1.2 pm and 3.0 pm, most preferably between 1.5 pm and 2.5 pm). Some inventive aspects and embodiments however may also use nanofibers, and therefore, in some embodiments 95% of the number of fibers have fiber diameter more broadly between 0.1 and 5 microns.

[0145] For a tighter and more controlled size range to the target range for the efficiency fibers 18, most preferably the fibers are melt-blown formed. Other options may include spun-bond fibers and / or needle-punch fibers; however, these techniques tend to produce fibers2360115347RBVD Ref. 513552-PCTtoward the higher end of the range. Yet other options are electro-spun or force-spun fibers, but these are used more typically for nanofibers, but these can be used for the lower end of the range. Therefore, more preferably, all of the efficiency fibers 18 are melt-blown fibers.

[0146] Also, for example, the polypropylene layer 12 can have a caliper thickness of between 0.1 mm and 0.4 millimeter, most preferably as only a single deposited web layer, and wherein the efficiency layer exhibits an initial air flow permeability of between 500 and 1200 CFM @ 125Pa. The efficiency layer here is not too bulky and excessive thickness is not utilized for pleat-ability aspects that may be necessitated when employed in framed pleated filter application (FIGS. 8-10) but also is sufficient for efficiency / capacity performance.

[0147] Media Performance & Degradation

[0148] With such parameter selections, the media composite 10, 10A, 10B will an initial filtration efficiency of at least a MERV 13 or 14 and can readily achieve an initial filtration efficiency of at least a MERV 16 as is typically desired in an embodiment.

[0149] Additionally, as shown below and in FIG. 7 (discussed later), the media composite can maintain an initial filtration efficiency of at least a MERV 16 when tested by one or more of the following degradation tests: (a) IPA vapor discharging (per ISO 16890 - 2022); (b) KC1 conditioning (per ASHRAE 52.2 - 2017 Appendix J); and / or (c) UV / sunlight testing, for example MIL-STD-810G Method 505.6 Procedure II degradation test - 2022. When selections are made pursuant to this disclosure, the media composite 10, 10 A, 10B can maintain an initial filtration efficiency of at least a MERV 16, when separate samples thereof are tested by all three of said degradation tests.

[0150] Substrate & Cover Layers

[0151] The substrate layer (e.g., polyester substrate layer 14) is provided to provide adequate support and typically pleat-ability / forming capabilities for the efficiency layer (propylene layer 12), and the protective layer (e.g., scrim 16A, 16B) is provided not for support but typically for protective qualities and so as not to interfere with pleat forming capabilities. In each instance little filtration capacity and negligible effects on air permeability are created with these layers, but those filtration properties are generally set by the efficiency layer 12.2460115347RBVD Ref. 513552-PCT

[0152] For example, the substrate layer preferably comprises fibers of polyester (by may additionally or alternatively comprise or be polypropylene, polyethylene, Nylon, and / or fiberglass), with a basis weight of between 50 gsm and 100 gsm.

[0153] For example, the protective layer preferably comprises fibers of polyester (by may additionally or alternatively comprise or be polypropylene, polyethylene, Nylon, and / or fiberglass), with a basis weight of between 5 gsm and 20 gsm, and is preferably a scrim.

[0154] Further discussion of exemplary details for efficiency layers 12, substrate layers 14 and protective layers 16A, 16B, and for the composite media 10, 10A, 10B can be had with reference to Table 1 below.

[0155] It is noted that in addition to different media layers, an adhesive is used which may be an added adhesive or a material scavenged of one of the layers (e.g. for sonic point bonding or thermal bonding such as using the low melt component of a bi-component fiber). As shown in FIG. 11, more preferably the adhesive comprises application of a laminating glue 24 of between 1 gsm amd 3 gsm that is applied between the efficiency layer 12 and the substrate layer 14; and a laminating glue 26 of between 1 gsm amd 3 gsm that is applied between the efficiency layer 12 and the protective layer 16A, 16B. In each instance, the glue 26 is typically applied (via spraying as shown, dip or laminating roll) to the more porous medias and not the efficiency layer 12 (i.e., glue being applied directly to the substrate layer 14 and / or the scrim 16A, 16B), to avoid occlusion of the tighter media of the efficiency layer 12.

[0156] Filter Media Useable in Embodiments Disclosed Herein

[0157] As shown in Table 1, some of the details described above and additional detail s / options for the medias and media selection used in an embodiment are indicated.

[0158] TABLE 1 PREFERRED FILTER MEDIA SELECTION PARAMETERS2560115347RBVD Ref. 513552-PCT> > < <2660115347RBVD Ref. 513552-PCT> >2760115347RBVD Ref. 513552-PCT> > < <

[0159] With such selections, the filter media may have MERV rating of at least 14 and for example an efficiency sufficient for various animal confinement applications. More preferably the filter media has at least a MERV 15 and more preferably a MERV 16 rating. The media is relatively open to air flow and permeable with an air flow.[0160J Implementation Of Composite Media In A Filter Element & Use

[0161] While other applications of the composite media 10, 10A, 10B may exist, one exemplary application is in filtration and filter elements in animal confinement or other long service life applications. Turning to FIGS. 8-11, a further embodiment is shown depicting a filter element 410 incorporating the degradation resistant composite filter media 10, 10A, 10B of any of the embodiments above (e.g. that of any of FIGS. 1-7) which may be used for various animal confinement applications such as for PRRSV in hog confinement or other animal confinement applications (e g. chickens, poultry, etc.), and its use may be in accordance with US Patent 9,510,557 to Crabtree, which has been incorporated by reference.

[0162] This filter element 410 may be used in wall and / or wall stud application of figures thirty-one to thirty-five of US Patent 9,510,557 to Crabtree which has been incorporated by reference in its entirety, The filter element 410 can be used in connection with one or more stages of upstream pre-filters as shown in these figures Crabtree. In an embodiment, the2860115347RBVD Ref. 513552-PCTcomposite media 10, 10A, 10B herein is employed in a 2-Stage or 3-Stage Filtration System Using Degradation Resistance Media Filter for Agriculture Barn Applications. The 3-Stage Air Filtration System is the same as the two-stage as in Crabtree, but has the following arrangement of an additional pre-filter stage: Stage 1 : A MERV5 to MERV8 media curtain to capture large particles; Stage 2: A MERV8 to MERV13, 2-inch depth pleated pre-filter to capture mediumsized particles; and Stage 3: A MERV14 to MERV16 (e.g. contain one of the composite media 10A, 10B, 10C herein) in a 6-inch depth box final-filter or a 12-inch V-bank final filter to capture small size particles.

[0163] The airflow direction is from Stage 1 to Stage 2, then to Stage 3. The Degradation Resistant Media (e.g., composite media 10, 10A, 10B) is used for the Stage 3 final filter (6-inch box or 12-inch Vbank shape) to capture small particles and enhance the filter’s lifespan due to superior degradation resistance.

[0164] As in figures thirty-one to thirty-five of US Patent 9,510,557 to Crabtree, both Stage 2 and Stage 3 filters are installed into a filter housing with latches on 4 edges for the Stage 3 final filter, and at 4 corners for the Stage 2 prefilter. The filter housing is mounted to the existing barn wall as per Crabtree. The distance between Stage 2 and Stage 3 filters can be within 2 inches.

[0165] Optionally, a further Stage 1 media curtain is installed approximately 1-1.5 meters away from the second and third stage housing, providing a service walkway allowing personnel to walk between the media curtain and the housing wall to install and uninstall the filters, as well as to clean the media curtain from the downstream side using reverse air flow.

[0166] This 3 Stage Air Filtration System, combined with the specified filters and the degradation resistant media composite 10, 10A, 10B, effectively controls viruses and bacteria in agriculture application, such as chicken barns and pig barns, that may reduce the animal death rate from 50% down to 5%.

[0167] According to this embodiment, the outer height and width dimensions can be the same as per a standard V-bank filter (e.g. the standard size in many applications is 2'x2').However, the depth of this embodiment can be considerably less, preferably less than 10 inches, more preferably less than 8 inches, and typically about 6 inches as shown in this embodiment, or even less than 6 inches. “About” is used to encompass rounding as fractions2960115347RBVD Ref. 513552-PCTcan be rounded up or down and fall within the about range; and that it is known that actual size in filtration applications are often off a small fraction from the listed dimension.

[0168] As noted above, this embodiment can be employed and used in any of the housings and systems of housing systems such as those of US 9,510,557, orthose animal confinement filtration systems in aforementioned patent publications that have been referenced in US 9,510,557, even those with 12 inch deep filter envelope regions. Simply by using this filter, considerable cost savings in freight shipment alone are significant given the fact that air filters are large and occupy considerable space. It can be seen that the filter element 410 also includes a common interface frame header that is received and mounts in any of such housings.

[0169] In one embodiment, the filter element has a height H dimensional span of 2 feet or 24 inches and a width dimension span of 2 feet or 24 inches. Each of these dimensions H and W are perpendicular and transverse to the depth dimension D (which is preferably about 6 inches or less). Depth dimension D is also the path along with the air flow travels through the filter element 410.

[0170] Alternatively, deeper pleats to provide a filter element depth of 12 inches or more may be employed with the filter. With this arrangement, greater capacity for a given volume is realized, such that fewer filter elements in a bank may be necessitated, and / or greater capacity or filter lifespan can be realized.

[0171] As shown in FIG. 8 and 9, the filter element 410 includes a rectangular plastic frame 414 that includes a rectangular frame header 412 and rectangular depending sidewall 416. Upstream and downstream rectangular gaskets 418, 420 may be mounted to upstream and downstream faces of the header 412 so that the filter element seals against the corresponding housing sealing surface (for example, see housing examples in US 9,510,557).

[0172] Situated in the frame is a rectangular pleated filter media pack 422 pleated from one of the media composites 10A. The media pack may have the sides glued and sealed to the sides of the frame 414 by urethane 424 or other sealant / bonding agent that lines the inside of the frame 414 as shown in FIG. 9 in surrounding relation of the media pack 422

[0173] Preferably, the upstream face of the media pack is recessed with the frame 414 as shown, which may provide spacing to be used for creation of a mixing chamber if used in conjunction with a separate upstream panel filter element (not shown).3060115347RBVD Ref. 513552-PCT

[0174] To better facilitate for structural integrity and high air flow, some preferred embodiments may include additional pleat supports and spacers between adjacent pleat flanks 434. For filter elements configured to operate in high-flow-rate environments, spacers, such as plastic finger spacers or hot-melt adhesives spaced at regular intervals, may be placed at regular intervals along the pleated filter media to add structural rigidity and prevent deformation of the media. In addition to being pleated with heat setting of the pleats, the filter media may also be embossed to add structural rigidity, to further increase surface area, and to increase the amount of media that can be manipulated into a volume for the filter element 410 and deep pleats. A method of embossed filter media is described in U.S. Pat. No.6,685,833. U.S. Pat. No. 5,290,447, U.S. Pat. No. 5,804,014, and DE 19755466 Al also describe methods of embossing that, in some embodiments, may be applied to the composite filter media of the present invention. Each of these patents are incorporated by reference in their entireties, as these or other pleating and embossing technologies may be used.

[0175] For example, integrally formed embossments 438 (grooves, folds or wrinkles extending between pleat tips 435 and between inlet and outlet faces) formed into the filter media and adhesive spacer beads 436 are illustrated on the filter media of filter media pack 422 as shown in FIGS. 9 and 10. Various numbers and arrangements of embossments can be provided. The adhesive beads are on adjacent pleat tips and extend along pleat sides and attach to each other as shown. This provides consistent pleat spacing and structural integrity to the pleated filter pack. These are particularly advantageous for the deep pleats contemplated herein. Adjacent pleat tips may be spaced between A and 2 centimeters to compact a substantial amount of filter media into the envelope while at the same time keeping an open flow structure to accommodate high air flow capacity. Also, the peat tips may be flattened with two creased edges 440 and a flat 442 therebetween as schematically illustrated in FIG.10. Flats 442 may between 1-3 millimeters wide in some embodiments.

[0176] Other Non-V Bank filter media packs are contemplated. For example, fluted filter media that is self-supporting and has alternating fluted sheets and facing sheets with alternating flutes closed proximate opposed ends such as shown in U.S. Pat. No. 5,820,646 are contemplated as an alternative to the pleated media pack 422 and may be substituted in some3160115347RBVD Ref. 513552-PCTembodiments. As such, U.S. Pat. No. 5,820,646 is hereby incorporated by reference in its entirety.

[0177] Methods For Creating Efficiency Layer And Laminating Composite Media

[0178] Turning to FIGS. 12-16, methods are schematically illustrated for (a) creating the efficiency layer 12; (b) process charging the efficiency layer 12; and then (c) laminating the efficiency layer 12 to the substrate layer 14, and optionally the protective layer 16A, 16B for forming composite medias 10, 10A, 10B.

[0179] In FIG. 12, a melt-blowing system 100 is shown comprising a screw 102 driven by a motor that generates frictional heat (or with supplemental heat) to melt pellets of polypropylene material 22 fed from a first hopper 104 and introduce / melt pellets of electret additive 20 from a second hopper 106. The pellets are controllably dose fed into the mixing chamber of a barrel 108 for the screw 102.

[0180] The arrangement of the electret additive 20 downstream of the base plastic material 22 may cause more material toward the surface and / or otherwise uneven distribution.Alternatively, only one hopper 104 may be used in which the electret additive and the polypropylene pellets are pre-mixed in the desired quantity before being feed into the barrel 108. In either event, the screw pressurizes and advances the polymer mixture (polypropylene and electret additive) toward a heated melt blow head 110, which is also subject to heated pressurized air 112 to melt blow fibers 18 onto a collector 114 such as a rotating drum (or belt or the like). The collected fibers 18 become a web entanglement and thereby the efficiency layer 12. The electret additive provides an initial electret charge to the efficiency layer 12.

[0181] Once the efficiency layer 12 is formed, the efficiency layer 12 is subjected to addition process charging as shown by alternatives of FIGS. 13 or 14, either of which may be used. In either embodiment of FIG. 13-14, the process charging comprises hydro-charging with a liquid comprising water with active drying thereafter. This provides a supplement electret charge to the efficiency layer 12 and / or enhances the charge effected by the electret additive 20.

[0182] For example, in FIG. 13 a multi-dip hydro-charge system 200 is shown. System has a first wetting tank 202 comprising of solution of water with a wetting agent (e.g. alcohol such3260115347RBVD Ref. 513552-PCTas IPA or potassium chloride (KC1)), which overcomes the hydrophobicity of the polypropylene doped with a fluoropolymer to allow saturation / soaking enhancement of the layer 12. Thereafter, the layer 12 is passed through at least one and preferably at least two downstream water wash tanks 204, 206. The first downstream wash tank 204 may obtain some contamination of wetting agent and may be considered more of a rinse with the last tank 206 a finishing tank. Positioned squeegees 108 may apply light pressure to partly dry and keep liquids to the desired tank. Subsequent drying via a dryer 210 is illustrated that can pass heated air flow blow and / or vacuum to actively dry the efficiency layer 12.

[0183] An alternative hydro-charging method is a spray system 220 in FIG. 14. This embodiment can deal with web hydrophobicity in at least a partially different way and uses pressure water sprayer 222 (additional downstream water sprayers may be used). Pressurized water pressure can overcome or help overcome hydrophobicity in order to introduce water into the efficiency layer 12. Preferably, no wetting agent is used, but some wetting agent may be used for lighter pressure applications or to more fully soak media (and if so, secondary water rinsing may be applied with subsequent spray heads similar to water sprayer 222). Once being charged with water by the sprayer 222, the efficiency layer 12 can be lightly pressed if desired such as by squeegee 224 and then subject to drier 226 similar to that of the prior embodiment of FIG. 13.

[0184] Once the efficiency layer 12 is additionally process charged as for example per FIG.13 or FIG. 14, then the media can be laminated to the substrate layer 14 and optionally a protective layer 16A, 16B to form the composite media as shown in laminating systems 300, 310 FIGS. 15 and 16. For example, laminating glue can be sprayed by laminating sprayer(s) 302, 304 (and / or heat applied) upon the substrate layer 14 and the scrim 16 respectively, with the layers overlayed upon each other as shown and then pressed lightly as with press rolls 306, 308, to form the composite media 10, 10A, 10B, that can then be collected on rolls 314 to be stored until later use (e.g. processing with a pleater).

[0185] ADDITIONAL DATA, OBSERVATIONS & EXAMPLES

[0186] A degradation resistant filter material is provided with a greater static charge stability, enhanced resistance to weathering degradation, improved filtration performance,3360115347RBVD Ref. 513552-PCTverified layer design, and optimized filter geometry. The altered hydro-charging method utilizes additives with electrets before extrusion to increase filtration efficiency.

[0187] In some embodiments, the degradation resistant filter media comprises a melt-blown layer, a first layer and a second layer. In some embodiments there is a melt-blown layer. In other embodiments, there is a melt-blown layer and a first layer. In other embodiments, there is a melt-blown layer and a second layer. Other embodiments may contain more layers or materials.

[0188] In most of the exemplary embodiments disclosed, the melt-blown layer is made of polypropylene and additives contain polytetrafluoroethylene and polypropylene, however, other materials may be used. Further, the substrate layer and scrim layer may be made of any material.

[0189] Referring to FIG. 1, a first embodiment of the degradation resistant filter media has been illustrated with a hydro-charged polypropylene melt-blown layer as the melt-blown layer and a polyester substrate layer as the first layer. In other embodiments, the substrate layer may be of a different material. In other embodiments, the melt-blown layer may be made out of a different material as one of ordinary skill in the art would understand.

[0190] In some embodiments, the melt-blown layer may have a first layer and a second layer. Referring now to FIG. 2, an exemplary embodiment with a hydro-charged polypropylene melt-blown layer as the melt-blown layer, polyester substrate as the first layer, and a scrim white as the second layer. In some embodiments, the melt-blown layer is laminated with the second layer.

[0191] FIG. 3 is an exemplary embodiment with a hydro-charged polypropylene melt-blown layer, a polyester substrate, and a scrim pigmented layer.

[0192] In some embodiments, pigment is used in the melt-blown layer, substrate layer, and / or the scrim layer. Pigment may be a color, white, or black that can be added to the material.

[0193] Referring to FIGS. 4-6, an exemplary embodiment of a resistant filter media sample fiber size is shown magnified at 5000x. For example, in FIG. 5B, see fiber material diameters of 1.901 pm and 2.487 pm.3460115347RBVD Ref. 513552-PCT

[0194] Referring to FIG. 7, exemplary pleated filter efficiency is shown. In this embodiment, filter efficiency was tested before and after 24 hours of IPA vapor per ISO 16890 standard conditioning method. Samples are shown along the bottom. Sample 2 was made with degradation resistant media without scrim layer. Sample 12 was made with degradation resistant media with scrim layer. Sample 13 was made with degradation resistant media with green pigment scrim layer. Sample 2, 12, and 13 all display significantly greater efficiency stability than the regular MERV16 media. Sample 7, 8, and 15 also used additives but they were not as effective as the present degradation resistant media.

[0195] Exemplary test results from a filter media efficiency test are shown in TABLE 2 below. The efficiency results samples are shown after zero days, five days, ten days, and fifteen days for 0.3 pm at 5.3 cm / sec.

[0196] Table 2

[0197] When analyzing testing data, a Fourier transform infrared spectroscopy of the degradation resistant filter media may be helpful to analyze results. Additionally, solar radiation tests may also be helpful in testing. Such as a standard environmental engineering test that is used by various industries to validate a product’s readiness for harsh conditions and extreme environments.

[0198] The following testing condition variations for are exemplary and were done with a UV lamp facing part of the material to help test efficiency. Sample 5 is made of a regular media with the melt blown layer facing the UV bulb. Sample 6 is a regular media with substrate facing the UV bulb. Sample 7 is a degradation resistant media without any pigment and with the melt blown layer facing a UV bulb. Sample 8 is a degradation resistant media without any pigment and with the substrate side facing a UV bulb. Sample 1 is a degradation resistant media without a pigmented scrim layer on top of a melt blown layer and with the scrim side facing the UV bulb. Sample 2 is a degradation resistant media without pigment in the scrim3560115347RBVD Ref. 513552-PCTlayer which is on top of melt blown layer and has a substrate side facing the UV bulb. Sample 3 is a degradation resistant media with a green pigment scrim layer on top of the melt blown layer and with the scrim side facing the UV bulb. Sample 4 is a degradation resistant media with green pigment scrim layer on top of melt blown layer and with substrate side facing the UVbulb.

[0199] In some embodiments, the melt-blown polypropylene media uses a fiber diameter ranging from 1.2 pm to 4.8 pm. In this embodiment, smaller fiber diameters risk reducing the degradation resistance and larger diameter fibers cannot maintain stable MERV 16 / 16A filter filtration efficiency. In a preferred embodiment, the optimized fiber diameter is 2.2 pm.

[0200] In some embodiments, the materials optimized melt flow index ranges from 900 to 1200. A higher melt flow index allows for smaller fiber sizes and faster extrusion speeds; however, a higher melt flow index may compromise fiber strength and uniformity. Uniform peak intensities observed in the Fourier-transform infrared spectroscopy (FTIR) analysis indicate highly ordered crystallinity throughout the polypropylene, contributing to its degradation resistance.

[0201] In some embodiments, about 5% additive is incorporated into the polypropylene resin during extrusion. In one embodiment, the additive consists of 20% polytetrafluoroethylene (PTFE) and 80% polypropylene, resulting in melt-blown media with a negative static charge, which helps maintain static charge stability during IPA vapor and KCI conditioning. The negative static charge may be approximately -0.06 kV to -0.2 kV.

[0202] In some embodiments, the melt-blown volume has a weight between 20 gsm and 28 gsm, which results in flat sheet efficiency of 98% to 99.8% when tested with 0.3 pm NaCl at 5.3 cm / sec.

[0203] In some embodiments, the melt-blown media needs to be laminated to a 100% polyester substrate with a weight of 50 gsm to 100 gsm. In some embodiments, the polyester substrate may be wetlaid or thermal bonded. In other embodiments, a heavier substrate may be used but it may cause pleatability issues, which makes scoring difficult. Further, it may increase resistance. In another embodiment, a lighter substrate may be used but it may affect pleat geometry and lead to laminating glue leakage.3660115347RBVD Ref. 513552-PCT

[0204] In some embodiments, a laminating glue of between 1 gsm and 3 gsm is applied between the melt-blown media and the substrate to ensure uniform bonding without delamination during processing and application.

[0205] In some embodiments, an optional third scrim layer of between 10 gsm and 20 gsm may be applied on top of the melt-blown media for additional surface protection.

[0206] In some embodiments, during application, the sequence of airflow can be: scrim layer, polypropylene melt-blown layer, and then polyester substrate. Or it can be the opposite way, depending on application. In some embodiments, the scrim layer may not be present.

[0207] In some embodiments, pigments may be incorporated into either or both the scrim layer or substrate layer to further prevent UV degradation. In some embodiments, only parts of the one or all of the layers include pigments. Pigments may be substances that impart black, white, or a color to other materials.

[0208] In some embodiments, a melt-blown layers I made from polypropylene with 1% to 15% additives that are mixed in prior to melt-blown extrusion. The additives contain 10% to 50% polytetrafluoroethylene (PTFE). The extruded fiber diameter has a range from 1 pm to 5 pm (however, in some embodiments nanofibers may be formed and included in which fiber diameter may range more broadly between 0.1 pm and 5 pm). The extruded media then passes through one or more water tanks, followed by a complete drying process.

[0209] In some embodiments, a laminated media comprises a melt-blown layer laminated with a hot melt glue or sonic bonding to a substrate. Where the substrate weight ranges from 40 gsm to 100 gsm. The substrate may include color pigments to enhance UV degradation resistance if the substrate layer is exposed to light. Further, in some embodiments, a scrim layer may be applied on the opposite side of the melt-blown layer, away from the substrate. In these embodiments, the scrim layer may range from 5 gsm to 20 gsm. The scrim layer may also include color pigments to improve UV degradation resistance if it is exposed to light.

[0210] In some embodiments, a filter is made with the aforementioned laminated media and is pleated. Pleat heights may range from 1 inch to 16 inches. Pleat-to-pleat spacing may range from 2 mm to 20 mm, depending on pleat height, media thickness, and desired airflow velocity. In some embodiments, embossed pleating technology is utilized. Hot melt glue lines may be applied between pleats. For assembly, hot melt or polyurethane potting may be utilized.3760115347RBVD Ref. 513552-PCTFurther, a plastic or metal frame may be used to encompass some or part of the laminated media.

[0211] Various aspects of the degradation resistant filter media are also illustrated in the following examples.EXAMPLES

[0212] Example 1. A melt-blown polypropylene with a basis weight of 22 gsm was extruded with 5% additives. The additive composition includes 20% polytetrafluoroethylene (PTFE) and 80% polypropylene. The polymer has a melt flow index of 1200, and the extruded fiber diameter ranges from 1.2 pm to 4.8 pm. After extrusion, the media is rinsed with water and fully dried. The dried melt-blown media is then laminated with 1-3 gsm of glue to a 70 gsm polyester substrate, serving as the final filter media as shown in FIG. 1.

[0213] In a particular example, there are two layers: a thermalbond nonwoven material with a basis weight of PET 70 gsm, and a melt-blown nonwoven material with a basis weight of PP 22 gsm. The layers are joined by a hot melt adhesive with a basis weight of Olefin 1 gsm. Total weight for this example is 93 gsm.

[0214] Performance testing results for this example include an initial efficiency of 99.9% at 0.3 pm and 5.3 cm / sec. The resistance was 3.28mm w.g. at 5.3 cm / sec. The post 24-hour IPA vapor efficiency was found to be 99.5% at 0.3 pm and 5.3 cm / sec (< 1% reduction).

[0215] For the following two exemplary tests, a UV chamber degradation was utilized to test efficiency of the layers with the lighting focused on different parts of the filter media. The UV chamber test utilized a Q-panel model QUV / spray for equipment, a UVA-340 bulb, irradiance of 0.85 WZ m2, temperature around 50°C / 122°F, and humidity less than 10%.

[0216] In one test example, the efficiency was tested utilizing a UV chamber degradation with the melt-blown layer facing UV lights. After 120 hours, the efficiency was 99.91%. After 240 hours, the efficiency was 99.77%. After 360 hours, the efficiency was 99.91%.

[0217] In another test example, the efficiency was tested utilizing a UV chamber degradation with the substrate layer facing the UV light. After 120 hours, the efficiency was 99.94%. After 240 hours, the efficiency was 99.82%. After 360 hours, the efficiency was 99.95%.3860115347RBVD Ref. 513552-PCT

[0218] The filter is made with 57 square feet of this media, and its geometry is shown in FIGS. 2a and 2b. The filter performance was tested and found to have a MERV 16 (El = 99.2%) overall initial efficiency at 500 ft / min. A 0.55 inch w.g. initial resistance at 500 ft / min. Post appendix J KCI conditioning efficiency to be MERV 16A (El = 96%). A MERV 16 (El = 96%) post 24-hour IPA vapor efficiency (0.3 pm - 1 pm) at 500 ft / min.

[0219] Example 2. Similar to Example 1, there is a melt-blown polypropylene with a basis weight of 22 gsm was extruded with 5% additives. The additive composition includes 20% polytetrafluoroethylene (PTFE) and 80% polypropylene. However, unlike Example 1, the polymer has a melt flow index of 1000, and the extruded fiber diameter ranges from 1.2 pm to 4.8 pm. After extrusion, the media is rinsed with water and fully dried. The dried melt-blown media is then laminated with 1-3 gsm of glue to one side of a 70 gsm polyester substrate and to a 16 gsm white polyester spunbond scrim on the other side, serving as the final filter media as shown in FIG. 2.

[0220] In a particular example, there are three layers: a thermal bond nonwoven material with a basis weight of PET 70 gsm, a melt-blown nonwoven material with a basis weight of PP 22 gsm, and a spunbond scrim (white) material with a basis weight of PET 16 gsm. Layers, or parts of the layers, are joined by a hot melt adhesive with a basis weight of olefin 4 gsm. Total weight for this example is 112 gsm.

[0221] Performance testing results for this example include an initial efficiency of 99.95% at 0.3 pm and 5.3 cm / sec. The resistance was 3.41 mm w.g. at 5.3 cm / sec.

[0222] For the following two exemplary tests, a UV chamber degradation was utilized to test efficiency of the layers with the lighting focused on different parts of the filter media. Similar to Example 1, the UV chamber test utilized a Q-panel model QUV / spray for equipment, a UVA-340 bulb, irradiance of 0.85 W / m2, temperature around 50°C / 122°F, and humidity less than 10%.

[0223] In one test example, the efficiency was tested utilizing a UV chamber degradation with the white scrim side facing the UV light. After 120 hours, the efficiency was 99.78%. After 240 hours, the efficiency was 99.93%. After 360 hours, the efficiency was 99.76%.

[0224] In another test example, the efficiency was tested utilizing a UV chamber degradation with the substrate side facing the UV light. After 120 hours, the efficiency was3960115347RBVD Ref. 513552-PCT99.79%. After 240 hours, the efficiency was 92.91%. After 360 hours, the efficiency was 99.89%.

[0225] The filter is made with 57 square feet of this media, and its geometry is shown in FIGS. 2 and 3. The filter performance was tested and found to have a MERV 16 (El = 98.6%) overall initial efficiency at 500 ft / min. A 0.536 inch w.g. initial resistance at 500 ft / min. A MERV 16 (El = 96.7%) post 24-hour IPA vapor efficiency (0.3 pm - 1 pm) at 500 ft / min.

[0226] Example 3. Similar to Example 1, there is a melt-blown polypropylene with a basis weight of 22 gsm was extruded with 5% additives. The additive composition includes 20% polytetrafluoroethylene (PTFE) and 80% polypropylene. The polymer has a melt flow index of 1000, and the extruded fiber diameter ranges from 1.2 pm to 4.8 pm. After extrusion, the media is rinsed with water and fully dried. Unlike Example 1, the dried melt-blown media is then laminated with 1-3 gsm of glue to one side of a 70 gsm polyester substrate and to a 16 gsm green polyester spunbond scrim on the other side, serving as the final filter media as shown in FIG. 3.

[0227] In a particular example, there are three layers: a thermalbond nonwoven material with a basis weight of PET 70 gsm, a melt-blown nonwoven material with a basis weight of PP 22 gsm, and a spunbond scrim (white) material with a basis weight of PET 16 gsm. Layers, or part of the layers, are joined by a hot melt adhesive with a basis weight of olefin 4 gsm. Total weight for this example is 112 gsm.

[0228] Performance testing results for this example include an initial efficiency of 99.95% at 0.3 pm and 5.3 cm / sec. The resistance was resistance: 3.47 mm w.g. at 5.3 cm / sec.

[0229] For the following two exemplary tests, a UV chamber degradation was utilized to test efficiency of the layers with the lighting focused on different parts of the filter media. Similar to Example 1 and Example 2, the UV chamber test utilized a Q-panel model QUV / spray for equipment, a UVA-340 bulb, irradiance of 0.85 W7 m2, temperature around 50°C / 122°F, and humidity less than 10%.

[0230] In one test example, the efficiency was tested utilizing a UV chamber degradation with the green scrim side facing the UV light. After 120 hours, the efficiency was 99.93%. After 240 hours, the efficiency was 99.92%. After 360 hours, the efficiency was 99.89%.4060115347RBVD Ref. 513552-PCT

[0231] In another test example, the efficiency was tested utilizing a UV chamber degradation with the substrate side facing the UV light. After 120 hours, the efficiency was 99.91%. After 240 hours, the efficiency was 92.90%. After 360 hours, the efficiency was 99.84%.

[0232] The filter is made with 57 square feet of this media, and its geometry is shown in FIGS. 2 and 3. The filter’s performance was tested and found to have a MERV 16 (El = 97.5%) overall initial efficiency at 500 ft / min. A 0.52 inch w.g. initial resistance at 500 ft / min. A MERV 16 (El = 95.3%) post 24-hour IPA vapor efficiency (0.3 pm - 1 pm) at 500 ft / min.

[0233] Measurement Techniques and Definitions

[0234] As used herein, “fiber diameter” and / or “fiber width” are meant to encompass the same thing, the measurement of the fiber width span (perpendicular to its axial length extension) as when viewed in two dimensions such as under a Scanning Electron Microscope (SEM). For example, measurements of fiber diameter are shown in FIGS. 4A-6C, where measurement at locations of fibers are taken with SEM measurements. Accordingly, as used herein "fiber diameter" refers to the width of the fiber when viewed in two dimensions and does not imply the fiber must be perfectly circular, and the term fiber diameter encompass fibers with irregular, oval, or oblong cross-sections as is understood and known. Even fibers with irregular, oval, or oblong cross-sections are therefore considered to have a “fiber diameter” that can be readily measured and analyzed using this methodology. Even though the fibers shown in FIGS. 4A-6C have been extruded from round orifices and have mostly round profiles subject to some variation as is typical, in the art and herein, the term “fiber diameter” therefore doesn't require nor imply a round fiber. “Fiber Diameter” and similar terms are a general term for measuring fiber width, which can encompass non-circular shapes including irregular / oblong / oval for sample. Further, if irregular / oblong / oval fibers are used in an embodiment, the “fiber diameter” measurement need not be taken along both the longest (major) and shortest (minor) axes to describe fibers that are oval, oblong, or irregular in shape; instead multiple width measurements of different fibers in the two dimension of a SEM image (e.g. taken from the upstream and / or downstream face of a sheet of filter media is simply used).4160115347RBVD Ref. 513552-PCT

[0235] Accordingly, measuring the width from an SEM image is a typical method, understanding that not all fibers are perfectly round in shape. Ordinarily if fiber formation orifice size and method parameters are controlled, then a relatively tight range of fiber sizes is produced, and average fiber diameter is readily ascertained. For example, a simplified table below shows exemplary measurements from three sample areas of an embodiment of the efficiency layer of improved degradation filtration media, in which the SEM image is taken from the inlet face or outlet face of a sheet of the filtration media.

[0236] TABLE 3. Measurement of fiber diameters (um)

[0237] If additional verification is needed for samples with more diameter variation (and or if fiber diameter varies due to non-circular type fibers such as oval / oblong), statistics can be used with a larger sample size, which can be a sample size of 100 fibers are measured from multiple different sample regions within the SEM images to ensure that the sample is representative of the overall fiber population in the web. The fibers are selected randomly to avoid any sampling bias. In such instances, measurements are done at locations intermediate between juncture points of fibers in the web (for example, as was done in FIGS. 4-6) After collecting the fiber diameter measurements, the average fiber diameter is calculated using the mean average formula: Average = (Sum of Observations) (Total Numbers of Observations).4260115347RBVD Ref. 513552-PCT

[0238] MERV ratings are tested according to ANSI / ASHRAE Standard 52.2-2017, The MERV test refers to the Minimum Efficiency Reporting Value (i.e. “MERV” rating). Pursuant thereto, the MERV value is a for filter element test, and not for flat sheet media. The tested filter used for qualification is 24in x 24inx 6in with 66 pleats, giving 57 square feet media area, and tested at 500ft / min as noted in which is a measure used to evaluate the effectives of air in trapping airborne particles of different sizes. Therefore, for the MERV rating test, the composite filter media 10, 10A, 10B is pleated and placed in a filter element frame such as for the intended application as shown in FIG 8. To see if a filter media provides for a MERV rating, the filter media is placed in a test filter used for MERV qualification that is 24in x 24inx 6in with 66 pleats, giving 57 square feet media area, and tested at 500ft / min, such as was done for the media composite constructions of FIGS. 1-3 discussed above in the above Examples.

[0239] While MERV is tested in a filter element construction, unless otherwise expressly indicated, all other measurements (e.g. air permeability, basis weight, thickness,) are measured in flat sheet (non-pleated) form.

[0240] Permeability measurements to determine air flow capacity (CFM - cubic feet per minute) are taken at pressure drop of 125Pa, and measurements can be done for example by a FX3300 Air Permeability Tester from TEXTEST Instruments.

[0241] Caliper thickness is simply the thickness of the individual media layer or composite media indicated and can be measured for example with a 1.5” diameter probe without additional weight.

[0242] Various degradation tests are used to evaluate potential lifespan of the filter media. This includes for example (1) a IPA vapor discharging (per ISO 16890 - 2022);test which can evaluate whether organic vapors / liquids and the like may reduce electret properties; (2) KC1 conditioning (per ASHRAE 52.2 - 2017 Appendix J), which uses potassium chloride (KC1) aerosol to simulate real-world filter efficiency degradation, especially for electret filters; (3) MIL-STD-810G Method 505.6 Procedure II degradation test - 2022, which is a solar radiation (sunshine) test, and evaluates the actinic effects of prolonged solar exposure, accelerating the degradation of materials exposed to long periods of sunshine. When degradation tests are performed, different samples of such media is tested separately to different tests; in other4360115347RBVD Ref. 513552-PCTwords, the same sample portion is not subjected to all three tests in sequence, but separately tested.

[0243] Further embodiments or aspects of this disclosure are described in the following numbered clauses:

[0244] 1 A laminated media, comprising: a hydro-charged polypropylene melt-blown layer with additives, wherein the layer has a first side and a second side; a polyester substrate layer, wherein the melt blown layer is laminated with an adhesive and adhered to at least part of the polyester substrate layer first side of the melt-blown layer; and a scrim layer, wherein the scrim layer is applied to at least part of the second side of the melt-blown layer.

[0245] 2. The laminated media as in clause 1, wherein the additives include one or more of the following: polypropylene, polytetrafluoroethylene, pigment, substance with electrets, plastic, polymer, corrosion resistant material, thermally stable material, natural substance, and synthetic substance.

[0246] 3. The laminated media as in clause 1, wherein the adhesive is a hot melt glue or sonic bonding.

[0247] 4. The laminated media as in clause 1, wherein the substrate layer has a weight of between 40 gsm and 100 gsm.

[0248] 5. The laminated media as in clause 1, wherein the substrate layer has pigments.

[0249] 6 The laminated media as in clause 1, wherein the scrim layer is between 5 gsm and 20 gsm.

[0250] 7. The laminated media as in clause 1, wherein the scrim layer includes pigments.

[0251] 8. The laminated media as in clause 1, wherein the laminated media is pleated.

[0252] 9. The laminated media as in clause 8, wherein the pleats have a height of between 2 inches and 16 inches.

[0253] 10. The laminated media as in clause 8, wherein the pleats have a pleat-to-pleat spacing of between 5 mm and 22 mm.

[0254] 11. The laminated media as in clause 8, wherein the laminated media is pleated using embossed pleating technology.

[0255] 12. The laminated media as in clause 8, wherein hot melt glue lines are applied between pleats.4460115347RBVD Ref. 513552-PCT

[0256] 13. The laminated media as in clause 8, further comprising: hot melt or polyurethane potting for assembly.

[0257] 14. The laminated media as in clause 8, further comprising: a plastic or metal frame, wherein the laminated media is placed within the frame.

[0258] 15. A filter element, comprising: a hydro-charged melt-blown thermoplastic with additives; and a material, wherein the melt-blown thermoplastic is bonded to the material.

[0259] 16. The filter element as in clause 15, wherein the thermoplastic is polypropylene.

[0260] 17. The filter element as in clause 15, wherein the additive composition includes 20% polytetrafluoroethylene (PTFE) and 80% polypropylene.

[0261] 18. The filter element as in clause 15, wherein the material is a polyester substrate.

[0262] 19. The filter element as in clause 15, wherein the material and melt-blown thermoplastic are bonded with between 1 gsm and 3 gsm hot melt adhesive.

[0263] 20. The filter element as in clause 15, wherein the melt-blown thermoplastic is at least 22 gsm and the material is at least 70 gsm.

[0264] 21. A method of creating a degradation-resistant filter material comprising: extruding a melt-blown thermoplastic with additives; rinsing the extruded thermoplastic with a liquid;drying the rinsed extruded thermoplastic; and laminating the dried thermoplastic with an adhesive to at least one layer.

[0265] 22. The method of clause 21, wherein the thermoplastic is polypropylene.

[0266] 23. The method of clause 21, wherein the thermoplastic is 22 gsm.

[0267] 24. The method of clause 21, wherein the melt-blown thermoplastic is extruded with 5% additives.

[0268] 25. The method of clause 21, wherein the additive comprises 20% polytetrafluoroethylene (PTFE) and 80% polypropylene.

[0269] 26. The method of clause 21, wherein melt-blown thermoplastic has a melt flow index of 1200.

[0270] 27. The method of clause 21, wherein the extruded fiber has a diameter of between 1.2 pm and 4.8 pm.

[0271] 28. The method of clause 21, wherein the liquid is water.4560115347RBVD Ref. 513552-PCT

[0272] 29. The method of clause 21, wherein the dried thermoplastic is laminated with between 1 gsm and 3 gsm of an adhesive.

[0273] 30. The method of clause 21, wherein the at least one layer is a polyester substrate.

[0274] 31. A method of creating a melt-blown layer, comprising: mixing polypropylene with between 1% and 10% additives, wherein the additives contains of between 10% and 50% polytetrafluoroethylene (PTFE); melt-blow extruding the mixture, wherein the extruded mixture has a diameter of between 2pm and 5 pm; passing the extruded mixture through at least one liquid tank; and drying the mixture.

[0275] 32. The method of clause 31, wherein the liquid in the liquid tank is water.

[0276] 33. The method of clause 31, wherein the polypropylene is mixed with 5% additives.

[0277] 34. The method of clause 31, wherein the additive contains 20% PTFE.

[0278] 35. A melt-blown layer, comprising: a polypropylene material and additives, wherein the additives comprise of between 10% and 50% PTFE, wherein the additives are mixed before melt-blown extrusion, further wherein the extruded fiber diameter ranges between 2 pm and 5 pm and wherein the extruded media passes through at least one liquid tank and a complete drying process.

[0279] The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the4660115347RBVD Ref. 513552-PCTinvention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0280] Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

[0281] Although the principles, embodiments and operation of the present invention have been described in detail herein, this is not to be construed as being limited to the particular illustrative forms disclosed. They will thus become apparent to those skilled in the art that various modifications of the embodiments herein can be made without departing from the spirit or scope of the invention.4760115347

Claims

RBVD Ref. 513552-PCTCLAIMS1. A media composite, comprising:an efficiency layer having a basis weight of between 20 gsm and 28 gsm and comprising fibers with a static charge, the fibers having an average fiber diameter ranging between 1.2 pm and 4.8 pm, the fibers comprising a polypropylene material and an electret additive incorporated in the polypropylene material;a substrate layer supporting the efficiency layer, the substrate layer being porous and laminated to the efficiency layer; andwherein the media composite provides an initial filtration efficiency of at least a MERV 13, when used in a filter element.

2. The media composite of claim 1, wherein the efficiency layer has a caliper thickness of between 0.1 mm and 0.4 millimeter, wherein the efficiency layer exhibits an initial air flow permeability of between 30 and 60 CFM @ 125Pa, and wherein 95% of the number of fibers of the efficiency layer have fiber diameter between 1 and 5 microns.

3. The media composite of any of claims 1-2, wherein the efficiency layer is provided with additional process charge, preferably a hydro-charge.

4. The media composite of any of claims 1-3, wherein the media composite provides an initial filtration efficiency of at least a MERV 16, when used in a filter element.

5. The media composite of any of claims 1-4, wherein the media composite can maintain an initial filtration efficiency of at least a MERV 16 when used in a filter element and tested by at least one of the following degradation tests:(a) IPA vapor discharging (per ISO 16890 - 2022);(b) KC1 conditioning (per ASHRAE 52.2 - 2017 Appendix J); and(c) MIL-STD-810G Method 505.6 Procedure II degradation test - 2022.

6. The media composite of claim 5, wherein the media composite can maintain an initial filtration efficiency of at least a MERV 16 when used in a filter element, when separate samples thereof are tested by all three of said degradation tests.

7. The media composite of any of claim 1-6, wherein an electret additive comprises fluorine, preferably a per- and / or polyfluoroalkyl substance.4860115347RBVD Ref. 513552-PCT8. The media composite of any of claims 1-7, wherein the electret additive comprises a fluoropolymer, preferably polytetrafluoroethylene (PTFE).

9. The media composite of any of claim 1-8, wherein the electret additive comprises a mixture of polypropylene and the fluoropolymer, by weight, between 50 % and 90 % polypropylene and between 10 % and 50 % fluoropolymer, and wherein the electret additive is preferably unevenly distributed with a base portion of the polypropylene material.

10. The media composite of any of claims 1-9, wherein the fibers of the efficiency layer comprise between 1 % and 5 % fluoropolymer in the fibers, by weight of the fibers, and wherein the fibers of the efficiency layer comprise between 95 % and 99 % of polypropylene, by weight of the fibers.

11. The media composite of any of claims 1-10, wherein the fibers of the efficiency layer further comprise one more additive(s) selected from the following group: silica, tourmaline, zirconium carbonate, calcium carbonate, polyvinylamine, anionic polyacrylamide, oxidized polyethylene wax, volcanic stone powder.

12. The media composite of any of claims 1-11, wherein the fibers of the efficiency layer having an average fiber diameter ranging between 1.2 pm and 3.0 pm, preferably between 1.5 pm and 2.5 pm.

13. The media composite of any of claims 1-12, wherein the negative static charge is at least -0.06 kV, and preferably approximately -0.06 to -0.2 kV.

14. The media composite of any of claims 1-13, wherein the fibers of the efficiency layer comprise melt-blown fibers, spun-bond fibers, force-spun fibers, and / or needle-punch fibers; and preferably are entirely melt-blown fibers.

15. The media composite of any of claims 1-14, wherein the substrate comprises fibers of polyester, polypropylene, polyethylene, Nylon, and / or fiberglass, and preferably the fibers of the substrate are entirely polyester; and wherein the substrate has a basis weight of between 50 gsm and 100 gsm.

16. The media composite of claim 8, wherein the substrate comprises:(a) an initial air flow permeability of greater than 100 CFM and more preferably between 500 and 120 CFM @ 125Pa,(b) a caliper thickness of between 0.3 mm and 0.6 mm,4960115347RBVD Ref. 513552-PCT(c) wherein the fibers of the substrate comprises an average fiber diameter of between 10 pm and 40 pm;(d) a MERV rating by itself of no greater than MERV 11 and more preferably less than MERV 8;(e) optionally includes pigments; andwherein the composite media has an initial air flow permeability of between 30 and 60 CFM @ 125Pa, and a caliper thickness of between 0.4 mm and 1.3 mm.

17. The media composite of any of claims 1-16, further comprising an adhesive facilitating said laminating comprising a glue, thermal bonding or sonic bonding, that is preferably a laminating glue of between 1 gsm amd 3 gsm that is applied between the melt-blown media and the substrate.

18. The media composite of any of claims 1-17, further comprising a porous protective layer laminated to the efficiency layer on a side of the opposite of the substrate layer.

19. The media composite of claim 18, wherein the porous protective layer comprises a fibrous scrim.

20. The media composite of any of claims 18-19, wherein the porous protective layer comprises fibers of polyester, polypropylene, polyethylene, Nylon, and / or fiberglass, and preferably the fibers of the protective layer are entirely polyester; and wherein the substrate has a basis weight of between 5 gsm and 20 gsm.

21. The media composite of any of claims 18-19, wherein the porous protective layer us preferably a scrim, and comprises:(a) an initial air flow permeability of greater than 100 CFM and more preferably between 1000 and 2000 CFM @ 125Pa,(b) a caliper thickness of between 0.1 mm and 0.3 mm,(c) wherein the fibers of the porous protect layer comprises an average fiber diameter of between 10 pm and 40 pm;(d) a MERV rating by itself of no greater than MERV 11 and more preferably less than MERV 5;(e) optionally includes pigments; andwherein the composite media has an initial air flow permeability of between 30 and 60 CFM @ 125Pa, and a caliper thickness of between 0.4 mm and 1.3 mm.5060115347RBVD Ref. 513552-PCT22. The media composite of any of claims 1-21, wherein the media composite is pleated into pleated filter media with pleats, that preferably have a height of between 1 inch and 16 inches, and preferably have a pleat-to-pleat spacing of between 2 mm and 22 mm.

23. The media composite as in claim 22, wherein pleated filter media further comprises embossments formed into pleat panels between scored pleat tips of the pleats, and preferably adhesive beads are applied between pleats stabilizing the pleats.

24. A filter element comprising the media composite of any of claims 1-23, comprising a frame defining a central cavity, with the media composite placed into the cavity and sealed to the frame to prevent unfiltered air flow from an inlet side to an outlet side.

25. A filter element comprising:a media composite providing the filter element with at least a MERV 14 rating, comprising:(a) an efficiency layer comprising an electret filter media;(b) a substrate layer supporting the efficiency layer, the substrate layer being porous and laminated to the efficiency layer; and(c) a porous protective layer arranged on a side of the efficiency layer opposite of the substrate layer; anda frame defining a central cavity, with the media composite placed into the cavity and sealed to the frame to prevent unfiltered air flow from an inlet side to an outlet side.

26. The filter element of claim 25, wherein the efficiency layer having a basis weight of between 20 gsm and 28 gsm and comprising fibers with a static charge, the fibers having an average fiber diameter ranging between 1.2 pm and 4.8 pm, the fibers comprising a polypropylene material and an electret additive incorporated in the polypropylene material; 27. The filter element of any of claims 25-26, wherein the efficiency layer has a caliper thickness of between 0.1 mm and 0.4 millimeter, wherein the efficiency layer exhibits an initial air flow permeability of between 30 and 60 CFM @ 125Pa, and wherein 95% of the number of fibers of the efficiency layer have fiber diameter between 1 and 5 microns.

28. The filter element of any of claims 25-27, wherein the efficiency layer is provided with additional process charge, preferably a hydro-charge.

29. The filter element of any of claims 25-28, wherein the filter element has an initial filtration efficiency of at least a MERV 16.5160115347RBVD Ref. 513552-PCT30. The filter element of any of claims 25-29, wherein the filter element can maintain an initial filtration efficiency of at least a MERV 16 tested by at least one of the following degradation tests:(a) IPA vapor discharging (per ISO 16890 - 2022);(b) KC1 conditioning (per ASHRAE 52.2 - 2017 Appendix J); and(c) MIL-STD-810G Method 505.6 Procedure II degradation test - 2022.

31. The filter element of any of claims 25-30, wherein the filter element can maintain an initial filtration efficiency of at least a MERV 16, when separate filter elements thereof are tested by all three of said degradation tests.

32. The filter element of any of claims 25-31, wherein an electret additive comprises fluorine, preferably a per- and / or polyfluoroalkyl substance.

33. The filter element of any of claims 25-32, wherein the electret additive comprises a fluoropolymer, preferably polytetrafluoroethylene (PTFE).

34. The filter element of any of claims 25-33, wherein the electret additive comprises a mixture of polypropylene and the fluoropolymer, by weight, between 50 % and 90 % polypropylene and between 10 % and 50 % fluoropolymer, and wherein the electret additive is preferably unevenly distributed with a base portion of the polypropylene material.

35. The filter element of any of claims 25-34, wherein the fibers of the efficiency layer comprise between 1 % and 5 % fluoropolymer in the fibers, by weight of the fibers, and wherein the fibers of the efficiency layer comprise between 95 % and 99 % of polypropylene, by weight of the fibers.

36. The filter element of any of claims 25-35, wherein the fibers of the efficiency layer further comprise one more additive(s) selected from the following group: silica, tourmaline, zirconium carbonate, calcium carbonate, polyvinylamine, anionic polyacrylamide, oxidized polyethylene wax, volcanic stone powder.

37. The filter element of any of claims 25-36, wherein the fibers of the efficiency layer having an average fiber diameter ranging between 1.2 pm and 3.0 pm, preferably between 1.5 pm and 2.5 pm.

38. The filter element of any of claims 25-37, wherein the negative static charge is at least -0.06 kV, and preferably approximately -0.06 to -0.2 kV.5260115347RBVD Ref. 513552-PCT39. The filter element of any of claims 25-38, wherein the fibers of the efficiency layer comprise melt-blown fibers, spun-bond fibers, force-spun fibers, and / or needle-punch fibers; and preferably are entirely melt-blown fibers.

40. The filter element of any of claims 25-39, wherein the substrate comprises fibers of polyester, polypropylene, polyethylene, Nylon, and / or fiberglass, and preferably the fibers of the substrate are entirely polyester; and wherein the substrate has a basis weight of between 50 gsm and 100 gsm.

41. The filter element of any of claims 25-40, wherein the substrate comprises:(a) an initial air flow permeability of greater than 100 CFM and more preferably between 500 and 120 CFM @ 125Pa,(b) a caliper thickness of between 0.3 mm and 0.6 mm,(c) wherein the fibers of the substrate comprises an average fiber diameter of between 10 pm and 40 pm;(d) a MERV rating by itself of no greater than MERV 11 and more preferably less than MERV 8;(e) optionally includes pigments; andwherein the composite media has an initial air flow permeability of between 30 and 60 CFM @ 125Pa, and a caliper thickness of between 0.4 mm and 1.3 mm.

42. The filter element of any of claims 25-41, further comprising an adhesive facilitating said laminating comprising a glue, thermal bonding or sonic bonding, that is preferably a laminating glue of between 1 gsm amd 3 gsm that is applied between the melt-blown media and the substrate.

43. The filter element of any of claims 25-42, wherein the porous protective layer comprises a fibrous scrim.

44. The filter element of any of claims 25-43, wherein the porous protective layer comprises fibers of polyester, polypropylene, polyethylene, Nylon, and / or fiberglass, and preferably the fibers of the protective layer are entirely polyester; and wherein the substrate has a basis weight of between 5 gsm and 20 gsm.

45. The filter element of any of claims 25-44, wherein the porous protective layer us preferably a scrim, and comprises:5360115347RBVD Ref. 513552-PCT(a) an initial air flow permeability of greater than 100 CFM and more preferably between 1000 and 2000 CFM @ 125Pa,(b) a caliper thickness of between 0.1 mm and 0.3 mm,(c) wherein the fibers of the porous protect layer comprises an average fiber diameter of between 10 pm and 40 pm;(d) a MERV rating by itself of no greater than MERV 11 and more preferably less than MERV 5;(e) optionally includes pigments; andwherein the composite media has an initial air flow permeability of between 30 and 60 CFM @ 125Pa, and a caliper thickness of between 0.4 mm and 1.3 mm.

46. The filter element of any of claims 25-45, wherein the media composite is pleated into pleated filter media with pleats, that preferably have a height of between 1 inch and 16 inches, and preferably have a pleat-to-pleat spacing of between 2 mm and 22 mm.

47. The filter element of any of claims 25-46, wherein pleated filter media further comprises embossments formed into pleat panels between scored pleat tips of the pleats, and preferably adhesive beads are applied between pleats stabilizing the pleats.

48. A method of using of the filter element according to any of claims 25-47 in an animal confinement building containing livestock.

49. The method of claim 48, further comprising using the filter element with a prefilter arranged proximate the filter element.

50. The method of claim 48, further comprising arranging a first stage of first stage prefilters upstream of said filter element with said prefilter, the first stage being spaced from said filter element with said prefilter by a service walkway.

51. A method of making a filter media, comprising:mixing polypropylene material with an electret additive to create an electret polymer mixture;extruding the electret polymer into a porous efficiency web layer having a basis weight of between 20 gsm and 28 gsm and comprising fibers with a static charge, the fibers having an average fiber diameter ranging between 1.2 pm and 4.8 pm; andprocess charging the efficiency web layer.5460115347RBVD Ref. 513552-PCT52. The method of claim 51, wherein the process charging comprises hydro-charging with a liquid comprising water with active drying thereafter, wherein the hydro-charging preferably comprising high-pressure spraying or dipping.

53. The method of claim 52, wherein the hydro-charging comprises using a wetting agent in solution with water, with additional water rinsing, the wetting agent preferably comprising potassium chloride or an alcohol.

54. The method of any of claims 51-53, wherein the extruding comprises melt-blowing, and wherein the electret additive comprises fluorine, preferably a per- and / or polyfluoroalkyl substance.

55. The method of claim 54, wherein the electret additive comprises a fluoropolymer, preferably polytetrafluoroethylene (PTFE).

56. The method of claim 55, wherein the electret additive comprises an electret additive mixture of polypropylene and the fluoropolymer, by weight, between 50 % and 90 % polypropylene and between 10 % and 50 % fluoropolymer, and wherein the method comprises:providing a first batch comprising polypropylene;providing a second batch of the combination additive mixture; andintroducing the second batch with the first batch to provide the an electret polymer mixture with an amount of polypropylene that is between 90%-99% by weight and an amount of the fluoropolymer that is between 1 %- 10% by weight, more preferably between 1% and 5%.

57. The method of any of claims 51-56, further comprising laminating the efficiency web layer to a substrate layer to provide a media composite, wherein the substrate comprises:(a) an initial air flow permeability of greater than 100 CFM and more preferably between 500 and 120 CFM @ 125Pa,(b) a caliper thickness of between 0.3 mm and 0.6 mm,(c) wherein the fibers of the substrate comprises an average fiber diameter of between 10 pm and 40 pm;(d) a MERV rating by itself of no greater than MERV 11 and more preferably less than MERV 8;(e) optionally includes pigments; and5560115347RBVD Ref. 513552-PCTwherein the composite media has an initial air flow permeability of between 30 and 60 CFM @ 125Pa, and a caliper thickness of between 0.4 mm and 1.3 mm.

58. The method of any of claims 57, further comprising laminating the efficiency web layer to a porous protective layer that is preferably a scrim, wherein the porous protective layer comprises:(a) an initial air flow permeability of greater than 100 CFM and more preferably between 1000 and 2000 CFM @ 125Pa,(b) a caliper thickness of between 0.1 mm and 0.3 mm,(c) wherein the fibers of the porous protect layer comprises an average fiber diameter of between 10 pm and 40 pm;(d) a MERV rating by itself of no greater than MERV 11 and more preferably less than MERV 5; and(e) optionally includes pigments.

59. The method of any of claims 51-58, wherein the media composite can maintain an initial filtration efficiency of at least a MERV 16 when used in a filter element.

60. The method of claim 59, wherein the media composite can maintain an initial filtration efficiency of at least a MERV 16 when used in a filter element, when tested by at least one of the following degradation tests:(a) IPA vapor discharging (per ISO 16890 - 2022);(b) KC1 conditioning (per ASHRAE 52.2 - 2017 Appendix J); and(c) MIL-STD-810G Method 505.6 Procedure II degradation test - 2022; and wherein preferably the media composite can maintain an initial filtration efficiency of at least a MERV 16, when separate samples thereof are tested by all three of said degradation tests.

61. The method of any of claims 51-60, wherein the efficiency layer has a caliper thickness of between 0.1 mm and 0.4 millimeter, wherein the efficiency layer exhibits an initial air flow permeability of between 30 and 60 CFM @ 125Pa, and wherein 95% of the number of fibers of the porous efficiency web layer have fiber diameter between 1 and 5 microns.5660115347

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