WO2018090280A1 - Filtre à air comprenant un support filtrant chargé de sorbant à fente discontinues - Google Patents

Filtre à air comprenant un support filtrant chargé de sorbant à fente discontinues Download PDF

Info

Publication number
WO2018090280A1
WO2018090280A1 PCT/CN2016/106224 CN2016106224W WO2018090280A1 WO 2018090280 A1 WO2018090280 A1 WO 2018090280A1 CN 2016106224 W CN2016106224 W CN 2016106224W WO 2018090280 A1 WO2018090280 A1 WO 2018090280A1
Authority
WO
WIPO (PCT)
Prior art keywords
air
air filter
filter media
substrate
skip
Prior art date
Application number
PCT/CN2016/106224
Other languages
English (en)
Inventor
Liang Cheng
Andrew R. Fox
Zhiqun Zhang
Himanshu Jasuja
Ann M. GILMAN
Shawn C. DODDS
Thomas J. Gilbert
Original Assignee
3M Innovative Properties Company
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 3M Innovative Properties Company filed Critical 3M Innovative Properties Company
Priority to PCT/CN2016/106224 priority Critical patent/WO2018090280A1/fr
Publication of WO2018090280A1 publication Critical patent/WO2018090280A1/fr

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D39/00—Filtering material for liquid or gaseous fluids
    • B01D39/14—Other self-supporting filtering material ; Other filtering material
    • B01D39/16—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres
    • B01D39/1607—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being fibrous
    • B01D39/1623—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being fibrous of synthetic origin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D39/00—Filtering material for liquid or gaseous fluids
    • B01D39/14—Other self-supporting filtering material ; Other filtering material
    • B01D39/16—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres
    • B01D39/1692—Other shaped material, e.g. perforated or porous sheets
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D39/00—Filtering material for liquid or gaseous fluids
    • B01D39/14—Other self-supporting filtering material ; Other filtering material
    • B01D39/20—Other self-supporting filtering material ; Other filtering material of inorganic material, e.g. asbestos paper, metallic filtering material of non-woven wires
    • B01D39/2027—Metallic material
    • B01D39/2041—Metallic material the material being filamentary or fibrous
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/04—Additives and treatments of the filtering material
    • B01D2239/0407—Additives and treatments of the filtering material comprising particulate additives, e.g. adsorbents

Definitions

  • Air filters are often used to remove airborne particles and/or to remove gaseous or vaporous substances, from an airstream.
  • air filter media comprising a porous, air-permeable substrate comprising an array of opened skip-slits and comprising a first major surface that is a sorbent-loaded surface.
  • Fig. 1 is a front view of a portion of an exemplary air filter media with opened skip-slits.
  • Fig. 2 is a cross-sectional schematic slice view of a portion (taken along line 2-2) of the air filter media of Fig. 1.
  • Fig. 3 is a front view of a portion of an exemplary substrate with unopened skip-slits.
  • Fig. 4 is a cross-sectional schematic slice view of a portion of another exemplary air filter media.
  • Fig. 5 is a cross-sectional schematic slice view of a portion of another exemplary air filter media.
  • Fig. 6 is a perspective exploded view of an exemplary air filter installed on a filter-support layer of an air-handling system.
  • Fig. 7 is a side schematic cross sectional view of a portion of an exemplary air-handling system with an exemplary air filter installed therein.
  • Fig. 8 is a perspective view of an exemplary framed, non-conformable air filter.
  • the term “generally” unless otherwise specifically defined, means that the property, attribute or relationship would be readily recognizable by a person of ordinary skill but without requiring absolute precision or a perfect match (e.g., within +/-20 %for quantifiable properties) ; the term “substantially” means to a high degree of approximation (e.g., within +/-10%for quantifiable properties) but again without requiring absolute precision or a perfect match.
  • the term “essentially” means to a very high degree of approximation (e.g., within plus or minus 2 %for quantifiable properties; it will be understood that the phrase “at least essentially” subsumes the specific case of an “exact” match. However, even an “exact” match, or any other characterization using terms such as e.g. same, equal, identical, uniform, constant, and the like, will be understood to be within the usual tolerances or measuring error applicable to the particular circumstance rather than requiring absolute precision or a perfect match. All references herein to numerical parameters (dimensions, ratios, and so on) are understood to be calculable (unless otherwise noted) by the use of average values derived from a number of measurements of the parameter. The term “configured to” and like terms is at least as restrictive as the term “adapted to” , and requires actual design intention to perform the specified function rather than mere physical capability of performing such a function.
  • Air filter media 10 may serve as, or be incorporated into, an air filter 1.
  • such an air filter may be a conformable, frameless filter that is e.g. installable on a filter-support layer 50 of an air-handling system 100, as shown in exemplary embodiment in Figs. 6 and 7.
  • such an air filter 1 may be a nonconformable, framed filter as shown in exemplary embodiment in Fig. 8.
  • air filter 1 may be rectangular in shape (which specifically includes square shapes) with four major lateral edges 4 and four corners (as shown e.g. in Fig. 6) ; in such embodiments filter media 10 may thus have a generally rectangular perimeter (which does not preclude irregularities, notches, chamfered or angled corners, or the like, in the perimeter of filter media 10) .
  • filter media 10 comprises a porous, air-permeable substrate 8 that comprises first major surface 11, which is a sorbent-loaded surface.
  • first major surface 11 which is a sorbent-loaded surface.
  • sorbent particles 14 are provided on major surface 11 so as to collectively comprise a sorbent layer 13.
  • Sorbent particles 14 are attached (e.g. adhesively bonded) to major surface 11 as discussed in detail later herein.
  • Substrate 8 also comprises second major surface 12; this surface may be sorbent-free or may likewise be loaded with sorbent particles.
  • sorbent particles 14 may be provided only in specific sorbent-loaded areas 26 of major surface 11 with other areas being sorbent-free; in other embodiments the entirety of major surface 11 may be a sorbent-loaded area 26.
  • substrate 8 comprises an array of opened skip-slits 20.
  • a slit is meant a narrow opening (e.g. with a length to greatest-width aspect ratio of greater than 4) that passes entirely through the thickness of substrate 8 from one surface 11 to the opposing surface 12, along a non-tortuous path.
  • skip-slits is meant an array of slits at least some of which are spaced along substrate 8 in a linear path that is aligned with the long axes of the spaced slits, with the linear path of the slits being interrupted by solid, unslit portions 7 of substrate 8.
  • opened skip-slits is meant that substrate 8 has been subjected to transverse stretching (at least generally along transverse direction T d as shown in Fig. 1) , of from about 2 %to about 15 %.
  • transverse stretching at least generally along transverse direction T d as shown in Fig. 1
  • This has the effect of transforming the slits from an initially formed configuration (i.e. after a slitting process) in which opposing transverse edges of each slit are in very close (e.g., within 0.5 mm) proximity to each other along the entire length of the slit.
  • uch an initial configuration, in a substrate that has been skip-slit but not yet subjected to transverse stretching to open the skip-slits is shown in exemplary embodiment in Fig. 3.
  • the transverse stretching pulls the slits slightly open so that for at least some of the slits, the opposing transverse edges of the slit are no longer in very close proximity to each other, but rather are, along at least at some portion their length, spaced apart from each other (e.g. a distance of 1 mm or more) .
  • the opened skip-slits of a skip-slit, transversely stretched substrate collectively exhibit an open area that occupies from about 2 %to about 10 %of the area of the substrate. (As used herein, the percent open area is the open area of the slits divided by the nominal area of the substrate, disregarding the porosity of the substrate.
  • the opened skip-slits of substrate 8 may exhibit an open area that occupies no more than about 8, 6, or 4 %of the nominal area of substrate 8. In further embodiments, the opened skip-slits of substrate 8 may exhibit an open area that occupies at least about 3, 4, 5 or 6 %of the nominal area of substrate 8.
  • a filter media 10 comprising a porous, air-permeable substrate 8 with a sorbent-loaded surface, and comprising opened skip-slits, can advantageously exhibit a low airflow resistance (as manifested by a low pressure drop being required in order to motivate airflow through the filter media) while at the same time exhibiting an excellent ability to capture a gaseous or vaporous substance from the moving air, as evidenced in the Examples herein.
  • the presence of the opened skip-slits may allow slight air leaks that allow a very low pressure drop to be achieved, while not allowing so much air to flow through the opened skip-slits, while still allowing sufficient air to flow in close proximity to the sorbent particles to achieve excellent ability to capture gaseous or vaporous substances from the air.
  • substrate 8 comprises numerous through-passages that extend from one major surface to the opposing major surface of substrate 8 to allow air to enter, flow through, and exit substrate 8.
  • passages may be tortuous passages.
  • the through-passages may be provided by interstitial spaces in between fibers of the fibrous nonwoven web.
  • substrates may be screened for their air permeability is by the use of an air-permeability densometer (such as those densometers available from Gurley Precision Instruments, Troy, NY) , in which the time is measured for a specified volume of air to be passed under a specified force through a specified area of the substrate (as described e.g. in U.S. Patent 6,858,290 to Mrozinski, which is incorporated by reference herein for this purpose) .
  • air-permeable is meant that a substrate 8 (or, in general, any layer described herein, such as a cover layer, a stabilizing layer, or an auxiliary filtration layer) exhibits a 50 cc Gurley densometer time of less than about 200 seconds.
  • a porous substrate 8 may exhibit a 50 cc Gurley densometer time of at most about 150, 100, 50, 20, 10, 5 or 2 seconds. In further embodiments, a porous substrate 8 may exhibit a 50 cc densometer time of at least about 0.2, 0.5, 1.0, 2.0, 4.0, 8, 16, 32, 64, or 128 seconds. (All Gurley densometer values presented herein are understood to be properties of the substrate that are measured in the absence of skip-slits and opened skip-slits.
  • a substrate 8 may also be characterized by way of a pressure drop as measured according to the procedures outlined in the Examples.
  • a porous, air-permeable substrate 8 in an unslit and unstretched condition may exhibit a pressure drop that is less than about 10, 6, 4, or 3 millimeters of water at a face velocity of 14 cm/sec.
  • a porous, air-permeable substrate 8 that is desired to be skip-slit and opened and to have sorbent loaded thereon can be of any suitable composition and configuration.
  • suitable materials for substrate 8 include air-permeable cellulosic materials (e.g. filter paper) , fibrous materials (whether organic materials, or inorganic materials such as fiberglass) , open-celled foam materials, and so on.
  • substrate 8 may be a knitted or woven material.
  • substrate 8 may be a nonwoven fibrous web, e.g. comprised of fibers of organic polymeric material. Such materials may be chosen from, for example, meltblown, meltspun, carded, wet-laid, or air-laid nonwoven webs.
  • Such materials may be consolidated (e.g. at least some of the fibers of the web may be bonded to each other to enhance the mechanical integrity of the web) e.g. by calendering, needle-tacking, cross-lapping, by the use of added binders, by so-called autogenous bonding as achieved e.g. by impinging heated air on the web, and so on.
  • Such materials may be comprised e.g. of organic polymeric fibers of any suitable composition, e.g. polyolefins, polyesters, polyamides, cellulosics, and so on, and mixtures of any such fibers. (The designation that such fibers may be organic does not preclude the presence of e.g. inorganic pigments, fillers, or the like. )
  • skip-slits 19 can be provided in substrate 8 by any suitable method, e.g. by rotary die cutting, laser cutting, and so on.
  • a rotary die may be formulated bearing cutting blades provided at locations at which a substrate is to be cut through, with gaps between the blades in regions where the substrate is to remain uncut.
  • Skip-slit substrate 8 will exhibit a longitudinal direction L d , with which the long axis of at least some of the slits are aligned and along which at least some of the slits are spaced with unslit areas 7 interspersed therebetween.
  • the slits may be provided in rows (which are oriented vertically in the view of Fig.
  • the spacing of individual slits along a row, and the transverse spacing of each row, can be uniform, or may be irregular as desired.
  • the unopened slits 19 are thus present as an array which may be regular or irregular.
  • the unopened slits may exhibit a length 1 and a transverse (between-row) spacing st.
  • the distance (along the longitudinal direction of substrate 8) between adjacent slits of any given row may be characterized by a center-to-center spacing s 1 , and may also be characterized by the end-to-end distance s le . All of these geometric parameters are illustrated in Fig. 3.
  • substrate 8 is stretched at least generally along the transverse direction Td to transform the array of skip-slits 19 as shown in Fig. 3, into an array of opened skip-slits 20 as shown in Fig. 1.
  • some of the above-described parameters of the unopened skip-slits 19 as depicted in Fig. 3 may correspond closely to the geometric parameters of the opened skip-slits 20 as depicted in Fig. 1.
  • parameters of (unopened) slits 19 such as the slit length 1 and the within-row slit spacings s 1 and s le as shown in Fig.
  • the opened skip-slits 20 of Fig. 1 will be characterized by a slit width W, which, for any slit, will be the widest transverse dimension along the length of the slit.
  • any such width of the slits will typically be less than 0.5 mm (and will typically be dictated by the width of the blades used e.g. in a rotary die) .
  • a skip-slitted substrate as disclosed herein is distinguished from e.g. a perforated (e.g. hole-punched) substrate in that no material has been removed from the substrate in the slitting process. This is in accordance with the fact that the transverse edges of a skip-slit may often be noticeably closer to each other than will be the case for edges of an opening that remain in a substrate after a discrete piece of the substrate is removed by hole-punching.
  • the geometric parameters of an unopened skip-slit array, and the resulting parameters of the opened skip-slit array may be chosen as desired.
  • the slit length 1 (and the resulting opened slit length L) may be at least about 2, 4, 6, or 8 mm.
  • the slit length 1 (and the resulting opened slit length L) may be at most about 20, 16, 12, or 10 mm.
  • the within-row (center-to-center) slit spacing s 1 (and the resulting opened slit spacing S 1 ) may be at least about 5, 7, 9, 11, 13, 15, 17, 19, 21, or 23 mm.
  • the within-row slit spacings s 1 and S 1 may be at most about 50, 40, 30, 20, 16, 12 or 8 mm. In various embodiments, the within-row (end-to-end) slit spacings s le and S le may be at least about 1, 2, 3, 4, 6, or 8 mm. In further embodiments, the within-row slit spacings s le and S le may be at most about 15, 12, 9, or 6 mm.
  • the transverse (between-row) spacing s t of the skip-slit array may be at least about 1, 2, 4, 6, or 8 mm. In various embodiments, the transverse (between-row) spacing s t may be at most about 16, 12, 10, 8, 6, 4 or 2 mm.
  • the transverse spacing S t of the opened skip-slit array (after transverse stretching) may be at least slightly higher than transverse spacing s t exhibited by the unopened skip-slit array as noted above. In various embodiments, the transverse (between-row) spacing S t of the opened skip-slit array may be at least about 2, 3, 4, 5, 6, or 8 mm.
  • the transverse (between-row) spacing S t of the opened skip-slit array may be at most about 16, 12, 10, 8, 6, 4 or 2 mm.
  • the slit width W of the opened skip-slits may be at least about 0.5, 1.0, 1.5, 2.0, 2.5, or 3.0 mm. In further embodiments, the slit width W of the opened skip-slits may be at most about 6.0, 5.0, 4.0, 3.0, 2.0, or 1.0 mm.
  • skip-slits 19 and the resulting opened skip-slits 20 do not necessarily have to be arranged strictly in linear rows comprising uniformly spaced slits. Nor do the rows necessarily need to necessarily be uniformly spaced across the transverse extent of the substrate. Similarly, the skip-slits do not necessarily need to be uniformly spaced down a row, or to exhibit uniform slit lengths. In short, in some embodiments the skip-slits can be present as an irregular array (with or without any discernable repeat pattern) .
  • the angle of the slits may not necessary be uniform, and/or the slits may not necessarily be strictly aligned, for example, perpendicularly to a transverse direction of the substrate as in the exemplary design of Figs. 1 and 3. In such cases, the above-discussed geometric parameters may still be obtained by using averaged values taken over a representative area of the array.
  • the configuration of a substrate 8 comprising opened skip-slits can also be characterized by the percent stretching that was performed. Such a percent stretching will have as its basis the initial (as-slit) state of the substrate; the before and after-stretching values can be obtained e.g. by providing fiducial markings on the substrate (so that the reported stretch is a linear stretch, across the transverse extent of the substrate) .
  • substrate 8 is transversely stretched to a stretching value of at least about 2.0, 4, 6, 8, or 10 percent. In further embodiments, substrate 8 is transversely stretched to a stretching value of at most about 20, 16, 12, or 8 percent.
  • the transverse stretching can be performed by the use of any suitable apparatus, e.g. a tentering frame or the like. The stretching can be performed e.g. batchwise, on individual pieces of substrate 8; or, it can be performed continuously e.g. by unwinding substrate 8 from a roll and processing it through a continuously-operating tenter apparatus. Any edge portions of substrate 8 that were e.g. held by grippers of a tenter apparatus, may be discarded as weed after the tentering operation and may be ignored in the calculations of stretching values and the like.
  • a porous, air-permeable substrate 8 that has been skip-slit and transversely stretched may exhibit a pressure drop that is less than about 5, 4, 3, 2.0, 1.0, or 0.5 millimeters of water at a face velocity of 14 cm/sec.
  • substrate 8 may tend to shrink, withdraw, or recover slightly along the transverse direction after the transverse stretching force is removed (due e.g. to residual stresses in fibers of a nonwoven web) .
  • the above-discussed percent stretching value will be understood to be a long-term value, measured after any such recovery, rather than being e.g. the peak transient stretching value achieved in the stretching process.
  • shrinkage may not be an issue and substrate 8 may remain at least substantially in its as-stretched configuration with little shrinkage or recovery.
  • the tendency of substrate 8 to shrink or recover (with e.g.
  • the stabilizing should be carried out with substrate 8 in an at least partially transversely stretched configuration (i.e., with substrate 8 exhibiting at least 2.0 %transverse stretch in comparison to its initial, unstretched configuration) .
  • Stabilizing of a stretched substrate 8 may be carried out in any desired manner.
  • a transversely-stretched substrate 8 may be affixed to a stabilizing layer 17 as shown in exemplary embodiment in Fig. 4.
  • the terminology of affixing is used broadly, e.g. regardless of whether substrate 8 is moved into contact with the affixed layer 17 or vice versa, and whether or not the affixed layer is in direct contact with substrate 8) .
  • the terminology of a stabilizing layer is similarly used broadly.
  • a stabilizing layer 17 might be a layer whose perimeter near or to the outermost edges of substrate 8 (in other words, a stabilizing layer 17 may cover, and may be affixed to, the entirety of the nominal area of substrate 8) .
  • a stabilizing layer might also take the form of one or more stabilizing members that e.g. extend at least generally along a transverse dimension of substrate 8 so as to resist a shrinkage force experienced by substrate 8.
  • Such a stabilizing member or collection of stabilizing members might take the form of e.g. one or more preformed strips that are bonded to a major surface of substrate 8. Or, they might take the form of e.g. elongated beads of hardenable material (e.g., hot melt adhesive or the like) that are deposited in flowable form and that then harden to form the stabilizing members.
  • hardenable material e.g., hot melt adhesive or the like
  • stabilizing layers there may not necessarily be a bright-line boundary between the above-described types of stabilizing layers.
  • items such as nettings, meshes, reticulated foams and the like that are affixed to substrate 8, can be considered to be stabilizing layers.
  • a stabilizing layer may take the form of a layer of expanded metal mesh that is coated with adhesive and then is adhesively bonded to substrate 8) . Any such stabilizing layer will allow sufficient airflow through substrate 8 to permit functioning of the filter media as disclosed herein. This may be achieved e.g. by way of an inherent air-permeability of the stabilizing layer (e.g., the layer may be a highly air-permeable porous material) .
  • a stabilizing layer may be comprised of one or more air-impermeable materials (which, for the purposes herein, can be considered to be a material that exhibits a Gurley time of more than 200 seconds) that occupy less than about 30, 20, 15, 10, or 5 percent of the area of substrate 8. Ifa stabilizing layer 17 is e.g.
  • a stabilizing layer of this general type will be at least air-permeable as defined herein and may be chosen so as to exhibit an advantageously low airflow resistance.
  • a stabilizing layer 17 may comprise a porous, air-permeable material that exhibits a Gurley time of at most about 100, 50, 20, 10, 5, 2, or 1 second.
  • a stabilizing layer that is in the form of a preformed layer or member (s) that is affixed to substrate 8, may be affixed to substrate 8 by any suitable method that does not unacceptably densify substrate 8 (or stabilizing layer 17 is layer 17 is air-permeable) .
  • suitable methods may include e.g. use of a pressure-sensitive adhesive, ultrasonic welding, solvent welding, needle-tacking, and so on. If a pressure-sensitive adhesive is used, it may be applied to a major surface of substrate 8 (e.g. to portions of fibers of a nonwoven web that provide the major surface of substrate 8 or to a major surface of stabilizing layer 17, as desired.
  • the fibers of the web can be entangled in such manner as to increase the stiffness and resistance to deformation of substrate 8, to a sufficient extent that such entangled fibers can serve as an in-situ stabilizing layer 17.
  • a sublayer of a substrate 8 e.g. proximate a major surface of substrate 8)
  • a stabilizing layer 17 may serve as a cover layer, as discussed in detail later herein.
  • a stabilizing layer 17 may possess sufficient stiffness that it at least substantially prevents a transversely-stretched substrate 8 from shrinking or withdrawing to any significant extent.
  • the transversely-stretched substrate 8 may at least substantially retain its stretched dimensions and may also be relatively planar in configuration.
  • relatively stiff nonwoven webs, reticulated foams, open-cell foams, polymeric meshes or nettings, or wire meshes or netting may be used as a stabilizing layer.
  • a stabilizing layer may only partially resist shrinkage or withdrawing of substrate 8.
  • a stabilizing layer may partially resist shrinkage of substrate 8 so that substrate 8, as it recovers slightly from the transverse stretching, assumes a somewhat three-dimensional configuration (in other words, substrate may assume a slightly wrinkled or corrugated configuration) . This may cause skip-slits 20 to remain open configuration. That is, even if the transverse edges of a slit are still in close proximity to each other along the transverse direction Td of substrate 8, a significant gap (of e.g.
  • a relatively nonstiff layer such as e.g. a low basis weight nonwoven or woven polymeric material can serve as a stabilizing layer 17.
  • substrate 8 comprises a first major surface 11 that is a sorbent-loaded surface.
  • surface 11 comprises sorbent particles 14 disposed thereon, so as to form a layer 13 of sorbent particles.
  • layer does not imply that the sorbent particles must form a continuous matrix or that they must form a “layer” that is handleable or self-supporting in the absence of the support provided by substrate 8.
  • First major surface 11 of filter media 10 will comprise at least one sorbent-loaded area 26 that comprises at least one sorbent (e.g. activated carbon) at a loading of at least about 10 grams per square meter (g/m 2 ) .
  • a sorbent-loaded area of major surface 11 may comprise a sorbent loading of at least about 20, 40, 60, 80, 100, 120, or 150 grams per square meter. It will be appreciated that although such loadings may increase the airflow resistance of the filter media somewhat, they will not completely occlude the filter media. So, the sorbent-loaded areas of air filter media 10 will still contribute to the particle filtration achieved by air filter 1.
  • a sorbent-loaded area (or multiple sorbent-loaded areas in combination) may occupy at least about 20, 40, 60, 70, 80, 90, 95, or 98 percent of the nominal area of major surface 11 of substrate 8.
  • sorbent particles 14 include activated carbon particles.
  • sorbent particles 14 may include e.g. alumina and other metal oxides; sodium bicarbonate; metal particles (e.g., silver particles) that can remove a component from a fluid by adsorption, chemical reaction, or amalgamation; particulate catalytic agents such as hopcalite (which can catalyze the oxidation of carbon monoxide) ; clay and other minerals treated with acidic solutions such as acetic acid or alkaline solutions such as aqueous sodium hydroxide; molecular sieves and other zeolites; silica; biocides; fungicides and virucides.
  • secondary sorbent particles may include any of the porous polymeric sorbents described in U.S. Provisional Patent Applications Nos. 62/269613, 62/269626, 62/298089, and 62/307831, all of which are incorporated by reference herein for this purpose. Mixtures of any of these types of sorbent particles may be used as desired.
  • Sorbent particles may be provided in any usable form including beads, flakes, granules or agglomerates. Sorbent particles may be configured to capture any desired gaseous or vaporous component from an airstream. At least some of the sorbent particles (e.g. activated carbon particles) may be impregnated with one or more additives as desired in order to enhance the ability of the particles to capture particular gaseous or vaporous substances.
  • the sorbent particle size may vary as desired.
  • the sorbent particles have a standard U.S. mesh size (rating) of at least about 12 mesh (corresponding to a nominal 1680 micrometer opening size) , at least about 16 mesh (1190 micrometers) , or at least about 20 mesh (840 micrometers) .
  • the sorbent particles have a standard U.S mesh size (rating) no greater than about 325 mesh (44 micrometers) , no greater than about 200 mesh (75 micrometers) , no greater than about 100 mesh (150 micrometers) , no greater than about 60 mesh (250 micrometers) , no greater than about 50 mesh (300 micrometers) , or no greater than about 45 mesh (355 micrometers) .
  • Suitable sorbent particles include 12x20, 25x45, and 30x60 mesh sized granular activated carbon available from Kuraray Chemical Corporation, Canoga Park, California. Mixtures (e.g., bimodal mixtures) of sorbent particles having different size ranges may also be employed.
  • filter media 10 will allow air filter media 10 to remove gaseous or vaporous substances from an airstream rather than e.g. performing only particle filtration.
  • the capability of filter media 10 to remove gaseous or vaporous substances from an airstream may be characterized by way of a toluene removal efficiency test as disclosed in the Examples herein.
  • filter media 10 may exhibit a toluene-removal efficiency of at least about 20, 25, 30, or 35 %. In further embodiments, filter media 10 may exhibit a toluene-removal efficiency of at most about 41, 36, or 31%. In various embodiments, filter media 10 may exhibit a toluene-removal Quality Factor of at least about 0.20, 0.25, 0.35, 0.45, or 0.55. (Any such efficiency parameters or Quality Factor parameters may be measured e.g. at a face velocity of about 75 cm/sec. )
  • first major surface 11 of substrate 8 e.g. a fibrous filtration web
  • first major surface 11 of substrate 8 may be done in any suitable manner. In some convenient embodiments, this can be done by providing a pressure-sensitive adhesive (PSA) on first major surface 11.
  • PSA pressure-sensitive adhesive
  • Such a PSA can be disposed on areas of surface 11 that are desired to become sorbent-loaded areas 26 of surface 11, by any suitable method.
  • a PSA precursor can be screen-printed onto such areas and liquid then removed from the precursor to leave behind PSA.
  • a PSA precursor might be a solvent-borne solution from which solvent is removed; or, a PSA precursor might take the form of a water-borne emulsion or dispersion (e.g., a latex) which coagulates to provide the PSA upon removal of the water.
  • a PSA precursor may be hot-melt-coated onto such areas and then cooled to solidify into a PSA.
  • an adhesive might be a so-called hot-melt adhesive that is deposited onto surface 11 in molten or semi-molten form, followed by sorbent particles being deposited thereon, with the hot-melt adhesive then being allowed to cool and solidify.
  • the PSA may not be necessary that the PSA be provided on surface 11 in a continuous manner (e.g., deposited as a layer that extends over the entirety of area 26 in an uninterrupted manner) . Rather, the PSA may be present at as low an area loading (e.g. coating weight per unit area) as can still provide adequate bonding of the sorbent particles to the fibers. This will minimize any effect of the PSA on the airflow resistance of the air filter media.
  • a PSA may be provided in area (s) 26 of major surface 11, at an area loading of at least about 2, 4 or 6 grams per square meter. In further embodiments, the PSA may be provided at an area loading of at most about 16, 14, 12 or 10 grams per square meter. Any suitable PSA may be chosen, and may be deposited according to the desired size and pattern of sorbent-loaded areas 26, e.g.
  • PSAs and/or PSA precursors may be chosen from e.g. the products available from BASF (Charlotte, NC) under the trade designation ACRONAL; the products available from 3M Company (St. Paul MN) under the trade designations SUPER 77 MULTIPURPOSE SPRAY ADHESIVE and HI STRENGTH 90 SPRAY ADHESIVE; the product available from ITW (Danvers, MA) under the trade designation DEVCON 5 MINUTE EPOXY; and the product available from Gorilla Glue, Inc.
  • the sorbent (s) can be deposited, e.g. gravity-dropped, onto the PSA, after which any non-bonded sorbent particles may be removed.
  • a cover layer e.g., a cover web
  • a cover web may be provided atop the thus-formed sorbent layer 13 if desired.
  • a sorbent-loaded area comprises a layer of sorbent particles (e.g. a monolayer, although the sorbent particles may occasionally be present in local arrangements resembling e.g. small stacks, piles, bunches, etc. ) that are present on a major surface of a fibrous web and are bonded (e.g., by an adhesive) to fiber portions that provide the major surface of the fibrous web.
  • sorbent particles e.g. a monolayer, although the sorbent particles may occasionally be present in local arrangements resembling e.g. small stacks, piles, bunches, etc.
  • Such an arrangement will be distinguished from arrangements in which sorbent particles are embedded within the interior of a fibrous web and are held within the web e.g. by way of physical entrapment by the fibers and/or by way of adhesive fibers, binding resins, or the like, that are present within the interior of the web.
  • the present arrangement will be distinguished from any arrangement in which significant numbers of sorbent particles are purposefully embedded within the interior of a fibrous web.
  • substrate 8 of filter media 10 may be provided with a cover layer 16, as shown in exemplary embodiment in Figs. 4 and 5.
  • a cover layer may be provided for aesthetic reasons and/or to aid in retaining sorbent particles 14 that might otherwise become dislodged from first major surface 11 of substrate 8 e.g. during processing and/or during the life of the air filter.
  • Cover layer 16 may be affixed to substrate 8 so that sorbent particles 14 are present as a layer 13 that is sandwiched between first major surface 11 of substrate 8, and a major surface of the cover layer, as shown in exemplary embodiment in Fig. 1.
  • Cover layer 16 may be affixed to substrate 8 (e.g., to a major surface of a nonwoven filtration web) by any suitable means, e.g. adhesive bonding, ultrasonic bonding, needle-tacking, and so on. If desired, points of attachment of cover layer 16 to substrate 8 may be preferentially located in sorbent-free areas, if any such areas are present on major surface 11 of substrate 8. In some embodiments, cover layer 16 may be attached to substrate 8 around the entirety of the perimeter of substrate 8 (e.g. in a continuous, uninterrupted manner) , with optional points of attachment within the interior area of substrate 8.
  • Cover layer 16 is at least air-permeable as defined herein and may be chosen so as to exhibit an advantageously low airflow resistance.
  • a cover layer 16 may comprise a porous, air-permeable material that exhibits a Gurley time of at most about 100, 50, 20, 10, 5, 2, or 1 second.
  • cover layer 16 may take the form of a nonwoven fibrous web (e.g. a scrim) that exhibits an area density of less than about 20 grams per square meter and a thickness of less than about 1 mm.
  • such a cover layer can exhibit an area density of less than about 16, 14, 12, or 10 grams per square meter, and can exhibit a thickness of less than about 0.8, 0.6, 0.4, 0.1, or 0.1 mm.
  • such a cover layer may be at least substantially impenetrable by sorbent particles (defined herein as meaning that, in ordinary use of filter 1, no more than 0.5 percent by weight of sorbent particles are able to escape through cover layer 16) .
  • cover layer 16 may be coterminous (i.e., occupying at least essentially the exact size and shape, and in complete overlapping relation) with the entirety of substrate 8.
  • a cover layer 16 may also serve as a stabilizing layer 17 (thus, a separate cover layer 16 and stabilizing layer 17 as shown in Fig. 4 would not be needed) .
  • substrate 8 may comprise the only layer present in filter media 10 that provides any significant filtration (aside from any relatively minor filtration e.g. of large particles, pet hair and the like that may be performed e.g. by a stabilizing layer 17 and/or by a cover layer 16) .
  • filter media 10 may comprise a secondary filtration layer 18 as shown in exemplary embodiment in Fig. 5, so that filter media 10 is a multilayer filter media.
  • Such a filtration layer 18 may be provided upstream, or downstream, of substrate 8.
  • Such a secondary filtration layer 18 may perform particle filtration, may capture gases or vaporous substances, or may perform both functions.
  • a layer may be comprised of any suitable materials, e.g. fibers, arranged in any suitable format. Such materials may be of a composition chosen from e.g. polyolefins such as polypropylene, polyethylene, or mixtures, blends, or copolymers thereof, or from poly (lactic acid) and like materials.
  • at least some of the fibers of layer 18 may comprise charged electret moieties.
  • electret is meant a material (e.g. an organic polymeric material) that, after a suitable charging processes, exhibits a quasi-permanent electric charge.
  • a secondary filtration layer 18 10 will meet the definition of a “charged” web (in terms of the change in Quality Factor upon exposure to an X-ray treatment) found in U.S. Patent No. 7691168.
  • Electret fibers capable of being charged may be chosen from any suitable material, e.g. split fibrillated charged fibers as described in U.S. Patent RE 30782. Such fibers can be formed into a nonwoven web by any suitable means.
  • layer 18 can be a meltblown nonwoven web (e.g., such as disclosed in U.S. Patent 4813948) or a meltspun (e.g. spunbonded) nonwoven web that comprises at least some fibers that comprise charged electret moities.
  • Nonwoven fibrous filter media that may be imparted with charged electret moieties and that may be particularly suitable for certain applications might include e.g. media of the general type described in U.S.
  • Patent 8162153 to Fox media of the general type described in U.S. Patent Application Publication 20080038976 to Berrigan; and, media of the general type described in U.S. Patent Application Publication 20040011204 to Both, and media generally known as tribocharged media.
  • Any suitable charging method may be used, chosen from e.g. corona charging, hydrocharging, tribocharging, and so on.
  • a secondary filtration layer 18 may be formed from pre-charged electret fibers; or, a layer may be formed (e.g. collected as a mass of fibers and then consolidated into a nonwoven web) and then post-charged.
  • the fibers of the media may comprise one or more charging additives, e.g. chosen from any of the additives described in International Patent Publication WO2016/033097.
  • porous substrate 8 itself may be charged according to any of the above disclosed arrangements and procedures.
  • filter media 10 (whether or not it comprises a secondary filtration layer 18) will exhibit at least about 30, 40, or 50 %filtration efficiency in a particle-filtration efficiency test (using NaCl particles) performed according to the methods disclosed in International Application No. PCT/CN2016/093657. In some embodiments, filter media 10 (again whether or not it comprises a secondary filtration layer 18) will exhibit a Quality Factor for particulate filtration of at least about 0.15, 0.3, 0.5, or 0.8, when tested according to the methods disclosed in the ‘657 application.
  • porous, air-permeable substrate 8 comprising an array of opened skip-slits and comprising a first major surface that is a sorbent-loaded surface may be used along with a secondary layer 18 that is configured for superior particulate-removal (e.g., may be a HEPA filter) .
  • substrate 8 may serve e.g. to remove nuisance (e.g. odorous) gases or vapors, without adding significant airflow resistance beyond that already presented by the secondary filtration layer 18.
  • an air filter 1 as described herein can find use in any suitable application in which it is desired to remove at least some gaseous or vaporous substances (noting that no bright-line distinction between such substances is intended) that are potentially present in air.
  • Such uses may involve personal devices (e.g. personal respiratory protection devices) designed for use by a single user, or collective devices (e.g. room air purifiers, HVAC systems, and so on) designed for e.g. buildings, vehicles, and other places where persons reside, work, or gather.
  • personal devices e.g. personal respiratory protection devices
  • collective devices e.g. room air purifiers, HVAC systems, and so on
  • Such uses may rely on an air filter 1 that is configured in any of a wide variety of geometric formats.
  • an air filter 1 may be included in a filter cartridge that can be fluidly coupled to a mask body to provide a personal respiratory protection device.
  • an air filter 1 may be incorporated into (e.g., may be a layer of) a “filtering face-piece” respirator mask in which the mask body itself provides the filtering function.
  • Filtering face-piece respirators often come in one of two configurations: molded (e.g. shaped, into a generally cup-shape so as to fit on a user’s face) , and flat-fold, that can be supplied in a flat or nearly-flat condition and can then be unfolded and expanded to fit on a user’s face.
  • An air filter 1 may be used in either type of respirator.
  • negative-pressure respirators that is, products in which the motive power for moving air is the breathing of a user rather than a separately provided motorized fan.
  • Such negative-pressure respirators are often configured as e.g. full-face respirators, half-face respirators, and hoods (e.g., escape hoods, smoke hoods, and the like) . All such products are encompassed by the term negative-pressure respirator, and air filter 1 may be used with any such product.
  • air filter 1 may be used in a respirator in which the motive power for moving air is a motorized fan or blower.
  • Such products may include e.g. a PAPR (powered air purifying respirator) .
  • air filter I may be located proximate the user’s face or head; or, it may be located remotely (e.g., positioned in a receptacle of a belt-worn housing) .
  • an air filter 1 may be a layer (e.g., a prefilter layer) of a multilayer filter media.
  • air filter 1 as disclosed herein may be used in any air-handling system.
  • an air-handling system might be e.g. a heating-ventilation-air-condition (HVAC) system (whether a centralized system or a so-called mini-split system as described below) , a room air purifier, a cabin air filter for a vehicle, a filter for an internal combustion engines, and so on.
  • HVAC heating-ventilation-air-condition
  • air filter 1 comprising air filter media 10 comprising substrate 8
  • air filter 1 may be installed in an air-handling system that is a so-called mini-split air-handling (e.g. HVAC or air conditioning) system.
  • Mini-split systems sometimes referred to as “ductless” systems
  • ductless air return often collect air locally via a single air return and comprise a blower that is designed to recirculate air within a single room, in contrast to e.g. whole-house, centralized HVAC systems.
  • Real-split HVAC systems include e.g. the products available from Fujitsu (Tokyo, JP) under the trade designation HALCYON. )
  • Fig. 7 depicts an intake portion of a mini-split air-handling system in idealized, generic representation and is non-limiting.
  • filter 1 is not necessarily required to be in close physical proximity to blower 101.
  • a filter cover 60 may be positioned upstream of filter 1 as depicted in Fig. 6.
  • Filter cover 60 should allow sufficient airflow to enable the functioning of the air-handling system and thus may be e.g. a perforated sheet material, a mesh or screen, a louvered or windowed material, and so on.
  • air filter 1 will be conformed to the shape of an upstream face 55 of an arcuate filter-support layer 50 of an air-handling system.
  • air filter media 10 will be conformable; moreover, no rigidifying perimeter support frame being present, air filter 1 will likewise be conformable.
  • the conformability is reversible and repeatable and can be performed manually by a user of air filter 1, without the need for any special tools.
  • Such an air filter, not bearing any kind of rigidifying frame or structure is distinguished e.g. from framed air filters that are permanently held in a planar configuration (irrespective of any local deviations due to e.g. a filter media being pleated) and from so-called cartridge filters that comprise one or more layers of filter media held permanently in an arcuate configuration.
  • filter media 10 may advantageously exhibit a relatively low stiffness.
  • the stiffness of the media may be characterized by a Taber Stiffness (measured as described in U.S. Patent No. 7235115, which is incorporated by reference herein for this purpose) .
  • filter media 10 may be comprised of a material that exhibits a Taber Stiffness of less than 1.0, 0.8, 0.6, or 0.4 Taber Stiffness Units.
  • the stiffness of the media may be characterized by a Gurley Stiffness (measured as described in U.S. Patent No. 7947142, which is incorporated by reference herein for this purpose) .
  • filter media 10 may be comprised of a material that exhibits a Gurley Stiffness of less than 100, 80, or 60 mg.
  • a frameless filter 1 and filter media 10 thereof does not include any kind of rigidifying perimeter support frame. However, this does not preclude the presence of one or more ancillary components e.g. proximate an edge of filter media 10. Such a component will be described by the term “border strip” for convenience herein. By definition, any such border strip or strips must serve some function (e.g., a fastening function, a decorative function, and so on) other than rigidifying filter 1 so that filter 1 cannot be conformed.
  • air filter 1 in many embodiments in which air filter 1 is installed in a mini-split air handling system, air filter 1 (e.g., side 3 thereof) may be in direct contact with upstream face 55 of filter-support layer 50. In such embodiments air filter 1 may thus comprise an upstream side 2 and a downstream side 3. In such embodiments it may be convenient for first major surface 11 of air filter 1 (the sorbent-loaded side) to be on the upstream side of the air filter.
  • filter-support layer 50 comprises an air-transmissive area 53 that comprises through-openings 52 through which air can easily pass to reach the interior of the air-handling system intake portion. However, air-transmissive area 53 also comprises solid portions 51 that serve to support filter 1.
  • Such solid portions 51 may take the form of e.g. struts of a grid or filaments of a mesh or screen as in the exemplary embodiment of Fig. 6; or, air-transmissive area 53 may take the form of a solid sheet material with numerous perforations extending therethrough.
  • one or more relatively (e.g., completely) non-air-transmissive areas of layer 50 may be provided (one such area 57 is shown in exemplary embodiment in Fig. 6) . Such areas may e.g. facilitate attaching filter-support layer 50 to the other components of the air-handling system, installing filter 1 on filter-support layer 50, or may serve any other purpose.
  • Filter-support layer 50 e.g., at least the air-transmissive area 53 thereof
  • Filter 1 may be conformed to match that shape when installed on filter-support layer 50.
  • a filter support layer 50 may not necessarily exhibit an arcuate shape, and does not necessarily have to be in close proximity to the blower fan of an air-handling system.
  • a mesh screen, louvered cover, perforated grille, or the like, of an air intake or air outlet (e.g. a register) of an air handling system may serve as a filter support layer on which a filter 1 as disclosed herein may be mounted.
  • a filter 1 may be installed e.g. on an upstream face 55 of a filter-support layer 50 by any suitable means.
  • adhesive strips e.g., at one or more edges 4 of filter 1
  • filter 1 may thus have components mounted thereto to facilitate installation onto filter-support layer 50.
  • filter 1 may simply consist of a sheet of air filter media 10 (including a sorbent layer, and a cover layer if present) .
  • filter-support layer 50 may have components (e.g.
  • filter-support layer 50 may comprise one or more deformable or non-deformable clips or the like.
  • fasteners that are supplied separately from filter 1 and from filter-support layer 50 may be used.
  • filter 1 may not necessarily be directly attached or adhered to air-transmissive area 53 of filter-support layer 50 (or, to any portion of upstream face 55 of filter-support layer 50) .
  • the concept of filter 1 being installed on an upstream face 55 of a filter-support layer 50 thus does not necessarily require actual direct attachment of the filter to the upstream face.
  • the installation may not involve any direct “attachment” of filter 1 to filter-support layer 50 at all.
  • filter 1 may be held in place on the upstream face of filter-support layer 50 by the pressure of being sandwiched between filter cover 60 and filter-support layer 50.
  • ends of filter 1 may be wrapped around edges of filter-support layer 50 and held by pressure between the edges of filter-support layer 50, and surfaces of some other component of the air-handling system, so as to maintain filter 1 in the desired location relative to filter-support layer 50. All such configurations fall under the general category of installing filter 1 on the upstream face of a filter-support layer 50 of an air-handling system.
  • an air filter 1 need not necessarily overlie an entire air-transmissive area 53 of a filter-support layer 50. That is, filter 1 may be configured (e.g., shaped and sized) so that when it is installed on the upstream face 55 of filter-support layer 50, at least one bypass region 54 is present in some area of filter-support layer 50 (e.g., near one or more edges thereof) as shown in exemplary embodiment in Fig. 6, that allows air to pass through filter-support layer 50 without passing through filter 1.
  • filter 1 may be configured so that, when it is installed on filter-support layer 50, a bypass ratio (defined as the ratio of the area of bypass region 54 to the total air-transmissive area 53 of filter-support layer 50) is obtained that is at least about 15, 20, 25, or 30 %.
  • air filter media 10 will occupy less than 85, 80, 75, or 70 %of the nominal air-transmissive area of filter-support screen.
  • the terminology nominal is used to denote that any small area occupied by e.g. the solid strands of a filter-support screen 50 will be disregarded in such calculations.
  • filter-support layer 50 may be e.g. a mesh or screen with relatively small through-hole sizes so that any relatively large particulate debris (e.g., pet hair, dirt, and so on) that may bypass filter 1 may still be captured rather than reaching the fan or blower of the air-handling system.
  • a high-bypass air-handling system may rely on multiple passes of air through the air-handling system (e.g. by recirculating room air into the system) in order to achieve the desired air filtration. It will be appreciated that such systems are distinguished from e.g. centralized HVAC systems in which single-pass filtration is desired (that is, in which essentially no air is to be returned to a centralized air-distribution blower that has not first passed through a filter) and in which an air filter is typically installed at a nominally 0 %bypass ratio.
  • the air-handling system may be operated as desired (for example to continuously or semi-continuously recirculate air, e.g. within a room) .
  • the visual appearance of the air filter e.g. the upstream face of the filter, which will be visible without having to remove the filter from the filter-support layer
  • filter media 10 may comprise a support frame 6 (made e.g. of any suitable material such as chipboard, and in the form of e.g. a channel frame or a pinch frame, as is well known) that is mounted on the perimeter of filter media 10 so that air filter 1 is a framed air filter.
  • a support frame 6 made e.g. of any suitable material such as chipboard, and in the form of e.g. a channel frame or a pinch frame, as is well known
  • air filter 1 is a framed air filter.
  • a framed filter may not necessarily have to be installed onto the upstream surface of a filter-support layer in the manner described above.
  • such a framed filter need not be conformable into an arcuate shape (and will in fact not be conformable) . Rather, in many air-handling systems (e.g.
  • a non-arcuate, framed air filter is inserted into a slot of the air-handling system so that portions of the filter frame are seated against retaining flanges of the air-handling system, rather than the filter being conformed to a filter-support layer and supported thereby.
  • filter media 10 is unpleated (meaning that no identifiable pleats with a pleat height of greater than 1.0 mm are present) .
  • filter media 10 may be pleated (e.g. as shown in Fig. 8) , for example with a pleat height in the range of about 150, 100, 50, 20, 15, 10, 5, 4, 3 or 2 mm.
  • Filter media 10 can be pleated by any suitable method, e.g. rotary-score pleating, blade-pleating, or processing the media through a set of corrugating gears.
  • Embodiment 1 is an air filter media, comprising a porous, air-permeable substrate comprising an array of opened skip-slits and comprising a first major surface that is a sorbent-loaded surface.
  • Embodiment 2 is the air filter media of embodiment 1 wherein sorbent particles are adhesively bonded, by way of a pressure-sensitive adhesive, to the first major surface of the porous, air-permeable substrate.
  • Embodiment 3 is the air filter media of any of embodiments 1-2 wherein the porous, air-permeable substrate is an organic polymeric nonwoven fibrous web.
  • Embodiment 4 is the air filter media of any of embodiments 1-3 wherein sorbent particles are present on the first major surface of the porous, air-permeable substrate at a loading of at least about 60 grams per square meter.
  • Embodiment 5 is the air filter media of any of embodiments 1-4 wherein the sorbent particles comprise activated carbon particles.
  • Embodiment 6 is the air filter media of embodiment 5 wherein the activated carbon particles exhibit a mesh size that is from about 20 mesh to about 325 mesh.
  • Embodiment 7 is the air filter media of any of embodiments 1-6 further comprising a nonwoven fibrous cover web that is affixed to the porous, air-permeable substrate so that sorbent particles of the sorbent-loaded surface are sandwiched between the first major surface of the porous, air-permeable substrate and a major surface of the cover web, wherein the cover web exhibits an area density of less than about 20 grams per square meter and a thickness of less than about 1 mm and is at least substantially impenetrable by the sorbent particles.
  • Embodiment 8 is the air filter media of any of embodiments 1-7 wherein the porous, air-permeable substrate is affixed to a stabilizing layer.
  • Embodiment 9 is the air filter media of embodiment 8 wherein the stabilizing layer is chosen from the group consisting of an organic polymeric netting, an organic polymeric mesh, an organic polymeric fibrous web, an adhesive-coated expanded metal mesh, and a collection of elongated beads of hardened material.
  • Embodiment 10 is the air filter media of any of embodiments 1-9 wherein the air filter media is a multilayer filter media that comprises the porous, air-permeable substrate and a secondary filtration layer.
  • Embodiment 11 is the air filter media of embodiment 10 wherein the secondary filtration layer is a fibrous web that comprises charged electret moities and wherein the multilayer filter media exhibits a Particle Filtration Efficiency of at least about 50 %.
  • Embodiment 12 is the air filter media of any of embodiments 1-11 wherein the opened slits collectively exhibit an open area that occupies from about 3 %to about 10 %of a nominal area of the substrate.
  • Embodiment 13 is the air filter media of any of embodiments 1-12 wherein the porous, air-permeable substrate comprising an array of opened skip-slits and comprising a first major surface that is a sorbent-loaded surface, exhibits a pressure drop of less than about 2.0 millimeters of water at a face velocity of about 14 cm/sec.
  • Embodiment 14 is the air filter media of any of embodiments 1-13 wherein the porous, air-permeable substrate comprising an array of opened skip-slits and comprising a first major surface that is a sorbent-loaded surface, exhibits a toluene-removal Quality Factor of at least about 0.25 at a face velocity of about 75 cm/sec.
  • Embodiment 15 is an air filter comprising the air filter media of any of embodiments 1-14.
  • Embodiment 16 is the air filter of embodiment 15 wherein the air filter media is a conformable, unframed air filter media that is configured to be installed on a portion of an upstream face of a filter-support layer of an air-handling system.
  • Embodiment 17 is the air filter of embodiment 16 wherein the air filter is a high bypass ratio air filter that is configured to be installed on a portion of an upstream face of a filter-support layer of an air-handling system, in a high bypass ratio configuration in which the air filter media occupies less than 85 %of a nominal air-transmissive area of the filter-support layer.
  • Embodiment 18 is the air filter of embodiment 15 comprising a support frame installed on a perimeter of the air filter media so that the air filter is a framed, nonconformable air filter.
  • Embodiment 19 is a method of making an air filter media, comprising the steps of: skip-slitting a porous, air-permeable substrate to provide an array of skip-slits in the substrate; transversely stretching the skip-slitted substrate so that the skip-slits are opened skip-slits; and depositing sorbent particles on a first major surface of the substrate so that the first major surface is a sorbent-loaded surface.
  • Embodiment 20 is the method of embodiment 19 further comprising affixing the skip-slitted, sorbent-loaded, transversely-stretched substrate to a stabilizing layer while the skip-slitted layer is in an at least partially transversely stretched configuration.
  • Embodiment 21 is the method of any of embodiments 19-20 further comprising affixing a cover layer to the first major surface of the substrate.
  • Embodiment 22 is a method of filtering air, the method comprising exposing an air filter comprising the air filter media of any of embodiments 1-14 to moving air so that at least some of the moving air passes through the filter media.
  • Particular-filtration parameters such as percent penetration, filtration efficiency, pressure drop and the filtration Quality Factor (QF) of a filter media sample can be determined using the apparatus and methods in the aforementioned ‘657 International Application.
  • Such methods use a challenge aerosol containing NaCl (sodium chloride) particles, delivered at a flow rate of approximately 85 liters/min to provide a face velocity of 14 crm/s, and evaluated using a TSI TM Model 8130 high-speed automated filter tester (commercially available from TSI Inc. ) .
  • the aerosol may contain particles with a diameter of approximately 0.26 ⁇ m mass mean diameter, and the Automated Filter Tester may be operated with the heater on and the particle neutralizer on.
  • Calibrated photometers may be employed at the filter inlet and outlet to measure the particle concentration and thus to obtain the %particle penetration through the filter. Filtration efficiency can be calculated as 100 minus the %particle penetration (and is reported in percent) .
  • An MKS pressure transducer (commercially available from MKS Instruments) may be employed to measure pressure drop ( ⁇ P, mm H2O) through the filter. The equation:
  • Units of QF are inverse pressure drop (reported in 1/mm H 2 0) .
  • a toluene removal efficiency test may be performed on samples of filter media, against a challenge of 40 parts per million (by volume) toluene at 50%relative humidity and a 245 LPM air flow (0.75 m/sface velocity) .
  • Toluene vapor may be generated by heating a liquid toluene solution in a 50%humid air stream.
  • Toluene concentration can be measured using a photoacoustic detector from California Analytical Instruments.
  • a filter media sample of any convenient size may be used, as long as the ratio of sorbent-loaded area to sorbent-free area of the particular sample tested is representative of that of the filter media as it is used in a filter.
  • Airflow resistance pressure drop
  • a toluene-removal quality factor may be obtained, which is calculated in analogous manner to the above-presented particulate-filtration quality factor, except that %toluene penetration is measured and used, rather than %particle filtration.
  • a nonwoven web was obtained from 3M Company, St. Paul MN, of the general type described in U.S. Patent 8162153.
  • the web was a spunbond web with a basis weight of 55 grams per square meter and an Effective Fiber Diameter (as defined and described in the ‘153 patent) comprising charged electret fibers and was unpleated.
  • a pressure-sensitive adhesive precursor was obtained from 3M St. Paul, MN) under the trade designation SUPER 77 MULTIPURPOSE SPRAY ADHESIVE.
  • the PSA precursor was coated (by spraying) onto a first maj or surface of a sheet of the nonwoven web, after the nonwoven web had been transversely stretched. The entirety of each sample (disregarding any edges that were discarded and not subjected to testing) was coated rather than only specific areas being coated.
  • the propellant of the spray adhesive was allowed to evaporate to leave behind a PSA, at an area loading (basis weight) that was not recorded.
  • Sorbent particles were obtained from Kuraray, JP, under the trade designation GWH.
  • the sorbent particles were activated carbon with a reported mesh size rating of 32 x 60.
  • the sorbent particles were manually gravity-sprinkled onto the first (adhesive-bearing) surface of the nonwoven web to excess, after which the web was inverted to remove unbonded particles therefrom.
  • the area coverage of sorbent particles was estimated to be in the range of approximately 100-140 grams per square meter.
  • the transversely-stretched, sorbent-loaded substrate was slightly tensioned by hand (to recover at least a portion of any stretching that had been lost due to post-stretching shrinkage) .
  • the perimeter edges of the substrate were then taped to a polymeric netting (obtained from JX Nippon ANCI, Narita, JP, under the trade designation CLAF S8522) .
  • the samples were then subjected to toluene-removal testing, with results as shown in Table 2.
  • Table 2 In the Q-Factor Ratio column, the Q-Factors of all samples are ratioed to that of Reference Example R-1.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Filtering Materials (AREA)

Abstract

L'invention concerne un support filtrant à air comprenant un substrat poreux perméable à l'air comprenant un réseau de fentes discontinues ouvertes et comprenant une première surface principale qui est une surface chargée de sorbant.
PCT/CN2016/106224 2016-11-17 2016-11-17 Filtre à air comprenant un support filtrant chargé de sorbant à fente discontinues WO2018090280A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/CN2016/106224 WO2018090280A1 (fr) 2016-11-17 2016-11-17 Filtre à air comprenant un support filtrant chargé de sorbant à fente discontinues

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2016/106224 WO2018090280A1 (fr) 2016-11-17 2016-11-17 Filtre à air comprenant un support filtrant chargé de sorbant à fente discontinues

Publications (1)

Publication Number Publication Date
WO2018090280A1 true WO2018090280A1 (fr) 2018-05-24

Family

ID=62145005

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2016/106224 WO2018090280A1 (fr) 2016-11-17 2016-11-17 Filtre à air comprenant un support filtrant chargé de sorbant à fente discontinues

Country Status (1)

Country Link
WO (1) WO2018090280A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022050676A1 (fr) * 2020-09-03 2022-03-10 주식회사 볼트크리에이션 Filtre à air polymère et son procédé de fabrication
US11305224B2 (en) 2017-04-18 2022-04-19 3M Innovative Properties Company Air filter media with post-pleat-deposited sorbent particles
US12109520B2 (en) 2019-01-21 2024-10-08 3M Innovative Properties Company Multi-layer, biodegradable composites for air filtration

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011133396A1 (fr) * 2010-04-22 2011-10-27 3M Innovative Properties Company Toiles fibreuses non tissées contenant des particules chimiquement actives et procédés de fabrication et d'utilisation desdites toiles
CN103768871A (zh) * 2014-01-23 2014-05-07 上海交通大学 具有3d结构的功能复合型空气净化滤芯

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011133396A1 (fr) * 2010-04-22 2011-10-27 3M Innovative Properties Company Toiles fibreuses non tissées contenant des particules chimiquement actives et procédés de fabrication et d'utilisation desdites toiles
CN103768871A (zh) * 2014-01-23 2014-05-07 上海交通大学 具有3d结构的功能复合型空气净化滤芯

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11305224B2 (en) 2017-04-18 2022-04-19 3M Innovative Properties Company Air filter media with post-pleat-deposited sorbent particles
US12109520B2 (en) 2019-01-21 2024-10-08 3M Innovative Properties Company Multi-layer, biodegradable composites for air filtration
WO2022050676A1 (fr) * 2020-09-03 2022-03-10 주식회사 볼트크리에이션 Filtre à air polymère et son procédé de fabrication

Similar Documents

Publication Publication Date Title
US11305224B2 (en) Air filter media with post-pleat-deposited sorbent particles
US20230372854A1 (en) Conformable pleated air filter with bridging filaments
EP3503991B1 (fr) Élément de filtre plissé comprenant des milieux filtrants plissés avec des barrages de bord, et procédé de fabrication et d'utilisation
US20130101477A1 (en) Non-woven electret fibrous webs and methods of making same
JP6109334B2 (ja) 不織布エレクトレット繊維ウェブ及びその製造方法
US11027231B2 (en) Air filter with visual filter life indicator zone and sorbent-loaded visual reference zone
WO2011088185A2 (fr) Filtre à air avec particules sorbantes
CA2926807A1 (fr) Filtre a air comprenant un film microperfore, et procede d'utilisation
US12017175B2 (en) Pleated air filter with bridging filaments and continuous-contact filaments
WO2018090280A1 (fr) Filtre à air comprenant un support filtrant chargé de sorbant à fente discontinues
TWI750208B (zh) 具有鈍化過濾器壽命指示器的空氣過濾器
WO2024214065A1 (fr) Milieu filtrant pour des dispositifs de filtration et leurs procédés de fabrication et d'utilisation
WO2021176291A1 (fr) Noyau de ventilateur de récupération d'énergie à contre-courant comprenant des mileux de support plissés sans soudure

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 16921775

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 16921775

Country of ref document: EP

Kind code of ref document: A1