Respiratory protection devices and methods of manufacturing the same

Abstract

A disposable respirator containing a sorbent media is presented that includes a layer of wrinkled media. The wrinkled media includes a first series of substantially parallel non-bonded elastic fibers or filaments between a first nonwoven porous web and a second nonwoven porous web. The first non- woven porous web comprises a sorbent material, wherein the sorbent material comprises sorbent particles having a mesh size between about 8x16 and 80x325. The first non-woven porous web is directly bonded to the second non-woven porous web. At least one portion of the wrinkled media is resiliently extensible under tension. The layer of wrinkled media is formed into the disposable respirator.

Description

RESPIRATORY PROTECTION DEVICES AND METHODS OF MANUFACTURING THE SAME TECHNICAL FIELD

[0001] Respiratory devices designed with wrinkled expandable filter media with adsorbents that enhanced adsorption capacity and enable elasticity, and low pressure drops. Respiratory devices designed with such wrinkled expandable filter media that enable high adsorption capacity, low pressure drops and elasticity, which reduce breathing resistance and provide enhanced service life and breathability to the wearer. SUMMARY

[0002] There is a desire to improve comfort and performance of respiratory protection devices.

[0003] A disposable respirator containing a sorbent media is presented that includes a layer of wrinkled media. The wrinkled media includes a first series of substantially parallel non-bonded elastic fibers or filaments between a first nonwoven porous web and a second nonwoven porous web. The first non- woven porous web comprises a sorbent material, wherein the sorbent material comprises sorbent particles having a mesh size between about 8x16 and 80x325. The first non-woven porous web is directly bonded to the second non-woven porous web. At least one portion of the wrinkled media is resiliently extensible under tension. The layer of wrinkled media is formed into the disposable respirator.

[0004] The above summary is not intended to describe each embodiment. The details of one or more embodiments of the invention are also set forth in the description below. Other features, objects, and advantages will be apparent from the description and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] FIG. 1 is a schematic representation showing shirred filter media that may be useful in embodiments herein.

[0006] FIG. 2 is a schematic representation of a cross section of the shirred filter media, showing its construction.

[0007] FIGS. 3A-3B are a schematic representation of 4 a shirred filter media according to one embodiment of the present disclosure.

[0008] FIG.4 illustrates a method of forming a respirator in accordance with embodiments herein.

[0009] FIGS. 5A-1 through 5C illustrate images of sorbent-loaded media described in the Examples herein.

[0010] FIGS.6A-6D illustrate stretching of a sorbent loaded media described in the Examples herein.

[0011] It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the disclosure. The schematic figures may not be drawn to scale. DETAILED DESCRIPTION

[0012] As used herein, the terms “a”, “an”, and “the” are used interchangeably and mean one or more; and “and / or” is used to indicate one or both stated cases may occur, for example A and / or B includes, (A and B) and (A or B).

[0013] Also herein, recitation of ranges by endpoints includes all numbers subsumed within that range (e.g., 1 to 10 includes 1.4, 1.9, 2.33, 5.75, 9.98, etc.).

[0014] Also herein, recitation of “at least one” includes all numbers of one and greater (e.g., at least 2, at least 4, at least 6, at least 8, at least 10, at least 25, at least 50, at least 100, etc.).

[0015] As used herein, “comprises at least one of” A, B, and C refers to element A by itself, element B by itself, element C by itself, A and B, A and C, B and C, and a combination of all three.

[0016] As used herein, the term “respirator” refers to a close-fitting facial covering device that filters inhaled and optionally exhaled air of particles and droplets. Respirators, as described herein, may be designed to seal to a user’s face along an uninterrupted seal perimeter (often referred to as a “racetrack”). Such features distinguish respirators from cloth face masks, surgical masks, etc. In some embodiments, respirators herein contain media that are electrically charged to attract particles, increasing capture efficiency and loading capacity with low pressure drop.

[0017] Disposable respirators are used in a variety of environments and industries. Ubiquitous at the height of the COVID-19 pandemic, disposable respirators come in a variety of makes and models. Some barriers for disposable respirator use and compliance include user comfort while wearing a respirator and respirator fit.

[0018] There are many different configurations of disposable respirators in the market. The vast majority of them however have fixed shapes and dimensions that do not stretch to accommodate the wearers’ facial movement such as yawning, laughing or talking as well as desired. In some cases, the respirator may slide or move with wearer’s facial movement that lead to poor fit and leaks or even scratches to wear’s face. Exemplary requirements set by the Occupational Health and Safety Administration can be found in 29 C.F.R. 1910.134. However, it is expressly contemplated that respirators in accordance with embodiments herein may be in compliance with other regulatory requirements either in the United States or globally.

[0019] A few respirator designs that do offer stretch flexibility either involve bulky plastic structure that maybe heavy or have limited stretchability with extra filter media. Described in embodiments herein are flexible, stretchable and resilient fit features that can be used with a number of respirator models. Such fit features may assist in enabling different respirator models to accommodate a larger range of face sizes, potentially increasing respirator compliance rates in workplaces.

[0020] Respirator fit concerns whether a respirator adequately seals to a wearer’s face. One example area of concern is the bridge of the nose. Nose cushions have been described in PCT publication WO 2022 / 235472, published on Nov. 10, 2022, as well as in US PAP 2008 / 0099022, published May 1, 2008. However, the described nose cushions are not stretchable. U.S. Pat.10,136,687, issued on Nov. 27, 2018, describes a nose notch or void area that receives the user’s nose, but is limited to a single fixed shape and, therefore, is only helpful for a limited range of nose bridge heigh and width.

[0021] PCT publication WO 2014 / 110075, published Jul.17, 2014, describes a face seal, but the face seal is not stretchable and is not formed of filtering material.

[0022] Respirator fit features are desired that improve a fit of a disposable respirator for a wearer, and increase a fit range of face sizes and profiles – e.g. fit features herein improve a respirator fit for an individual, and increase the number of individuals for whom a respirator can be used.

[0023] The use of wrinkled media in respirators, as described for example in U.S. Provisional Patent Apps. 63 / 496,002 and 63 / 496,003, both filed April 13, 2023 provides both a larger surface area than flat sheet media while maintaining more compact or lower profile than pleat pack with good conformity.

[0024] The term “wrinkled media,” as used herein, refers to a type of functional media laminate with optional reticulated support in the overall respirator designs. Wrinkled media is described in greater detail with respect to function in the Examples section of US Provisional Patent Application 63 / 434365, Filed December 21, 2022, which is incorporated by reference herein. The terms “shirred media” and “wrinkled media’ are used herein interchangeably.

[0025] Embodiments herein use wrinkled media to form fit features that improve the fit of disposable respirators. Fit features herein exhibit stretchability and a resilience to stretch. Fit features herein may increase a fit and / or comfort of a respirator. Fit features herein can be incorporated into a respirator during a respirator manufacturing process, potentially without adding a rate limiting step.

[0026] In some embodiments, fit features include a face seal made of wrinkled media having a low contact pressure as well as the same or higher filtration performance as the media used for the respirator body. Face seals herein actively stretch and act as a “spacer” to help respirators better fit to narrower or shorter faces. The stretchability and resilience of face seals herein help maintain fit during awearer’s facial and head movements. Face seals herein can be manufactured to fit any respirator style, shape or size – such as cup styles, vertical flat fold styles, horizontal flat fold styles, etc.

[0027] Some embodiments herein include fit features formed of material selected for sustainability and / or recyclability. Prior art respirator construction often utilizes polyurethane foam, which is crosslinked during formation to maintain a structure. Fit features herein, in some embodiments, are formed of a remeltable material.

[0028] Shown in FIG.1 is top view of an exemplary embodiment of a shirred filter media of the present disclosure. Shirred filter media 10 comprises a plurality of elastic fibers that are spaced apart. As used herein, the term fiber is used to refer to a multifilament system. Most but not all of elastane fibers, for example, are formed from multiple filaments. It is expressly contemplated that embodiments herein may use either elastic monofilaments or elastic fibers, depending on the application of the final media. The plurality of elastic fibers or filaments are sandwiched between two non-woven porous fibrous webs. During fabrication of the shirred filter media (herein referred to as “wrinkled media”), the elastic fibers or filaments are pulled under tension, such that when the tension is released, the non-woven porous fibrous webs become puckered. Shown in Fig. 2 is a side view of filter media 20 showing a first non-woven porous fibrous web 24 and a second non-woven porous fibrous web 26, with elastic fiber or filament 22 positioned therebetween. FIG. 2 shows that first non-woven porous fibrous web 24 is in direct contact with second non-woven porous fibrous web 26. Either media web 24 or 26 or both may contain sorbent particles. Based on the resulting articles, it is believed that when adhesive is used, the adhesive bonds the two non-woven porous fibrous webs together with the fibers or filaments therebetween. It is assumed that the bonding of the first and second non-woven porous fibrous webs is discontinuous and that the non-woven porous fibrous web(s) may not be bonded (for example, adhesively bonded) to the fibers or filaments along the full length of the fibers or filaments. Material Tables – Nonwoven Media

[0029] Table 1 lists the nonwoven webs used in making shirred media as described in US Provisional Patent Application 63 / 434365, Filed December 21, 2022 and Tables 2 and 3 list their initial pressure drop (dP) and penetration in NaCl and DOP tests.

[0030] The effective fiber diameter (EFD) can be estimated by using the measured pressure drop across a filter of known material according to the method set forth in C. N. Davies, Air Filtration (Academic, London, 1973).Table 1. Nonwoven webs used in making shirred media and respirators Media Media Material Source Properties ID F1 Polypropylene A non-woven meltblown fibrous web Having a basis weight of 16 having fibers with a charging additive gsm, a thickness of 0.010 in package as described in US 10,724,171 (0.26 mm), 6.6% solidity, and an (Schultz et al.), which can be prepared per effective fiber diameter of 6.5 Process A and Charging Method 3 as micrometers. disclosed in US 10,724,171. F2 Polypropylene A non-woven meltblown fibrous web Having a basis weight of 61 having fibers with a charging additive gsm, a thickness of 0.035 in package as described in US 10,724,171, (0.88 mm), and an effective fiber which can be prepared per Process A and diameter of 7.5 micrometers. Charging Method 3 as disclosed in US 10,724,171. F4 Polypropylene A non-woven meltblown fibrous web Having a basis weight of 18 having fibers with a charging additive gsm, a thickness of 0.008 in package as described in US 10,724,171, (0.19 mm), 7.7% solidity, and an which can be prepared per Process A and effective fiber diameter of 7.0 Charging Method 3 as disclosed in US micrometers. 10,724,171. F5 Polypropylene A non-woven meltblown fibrous web Having a basis weight of 228 non-woven web having 25x50 mesh 80 CTC coconut shell gsm and thickness of 1.65 mm. and activated activated carbon particles, for organic carbon particles vapor (OV) adsorption, incorporated substantially on one surface of the non- woven media. F6 Polypropylene A non-woven meltblown fibrous web Having a basis weight of 129 non-woven web having 80x325 mesh 60 CTC coconut shell gsm and thickness of 1.3 mm. and activated activated carbon particles, for OV carbon particles adsorption, incorporated throughout the non-woven media depth. F7 Polypropylene A non-woven meltblown fibrous web Having a basis weight of 214 non-woven web having 40x140 mesh 80 CTC base treated gsm and thickness of 1.4 mm. and activated activated carbon particles, for acid gas carbon particles (AG) adsorption, incorporated throughout the non-woven media depth. F8 Polypropylene A non-woven meltblown fibrous web Having a basis weight of 217 non-woven web having 60x80 mesh polymeric sorbent gsm and thickness of 1.6 mm. and polymeric particles, for aldehyde adsorption as sorbent described in US 10,780,416 B2, particles incorporated throughout the non-woven media depth.Table 2. Flat nonwoven webs’ initial dP and penetration in NaCl tests Flat Nonwoven Media websNaCl test at 13.9 cm / s Media Media Initial dP Initial Pen QF ID. (mmH2O) F1 Meltblown 6.5 µm 1.1 14% 1.8 F2 Meltblown 7.5 µm 6.8 0.17% 0.94 F4 Meltblown 7 µm 2 15% 0.95 Table 3. Flat sorbent nonwoven webs’ initial dP and penetration in NaCl tests Flat Sorbent loaded Nonwoven Media websNaCl test at 13.9 cm / s Media Media Initial dP Initial QF ID. (mmH2O) Pen F5 OV sorbent loaded web 14.5 0.07% 0.50 with meltblown web F6 OV sorbent loaded web 3.0 83% 0.06 F7 AG sorbent loaded web 2.55 83% 0.07 F8 Polymeric sorbent loaded 2.9 77% 0.09 web Elastic filaments

[0031] The elastic filament or elastic fibers, which may contain one or more elastic filaments, of the present application comprise a co-polymer and are elastic in nature, meaning that the fiber is capable of recovering or at least partially recovering in length following stretching. One such fiber is available under the trade designation “100% Lycra ® Spandex 235 Multifil”, DTEX Type 737, 210 denier from Invista Company, Wichita, Kansas. Another example elastic filament example is a copolymer made of propylene and ethylene having a density ranging between 0.85-0.9 g / cc. Exemplary types of polymeric materials that may be used for fibers of the present application include: natural rubber, synthetic rubber, polyether-polyurethanes, polyamides, polyisoprenes, copolymers of isoprene and neoprene, polymers of 2-chloro-1, 3-butadiene, polyether-polyurea copolymer (e.g., Lycra®), polyurethane (e.g., Spandex®). Other examples include Kraton™ copolymers. Those are elastomeric tri-block polymers comprising high Tg end blocks made of polystyrene and low Tg center block made of one or more isoprene, butadiene, and the like.

[0032] In one embodiment, the elastic fibers or filaments have a diameter of at least 1, 5, 10, or even 20 micrometers and at most 25, 50, 100, 200, 400, 600, 800, 1000, 1200 micrometers. In one embodiment, the fibers have a denier of at least 100, 150, 175, 200, 210, 220, 250, or even 500. In one embodiment, the fibers have a denier of at most 1200, 900, 800, 700, 600, 500, 400, 350, 300, 250, or even 225 denier.Non-woven porous fibrous web

[0033] The plurality of elastic fibers or filaments is positioned between two non-woven porous fibrous webs, herein referred to as a non-woven web. The nonwoven webs of the present disclosure can be made by wet laid, carded, air laid, spunlaced, spunbonding, spunmelt, or melt-blowing techniques or combinations thereof. The nonwoven webs herein may also be formed of fibrillated film fibers. The nonwoven webs herein may also be formed of fibrillated film (for example that described in US Patent RE32171, published on June 3, 1986).

[0034] In some embodiments, a nonwoven web may undergo a relofting step after formation to increase loftiness. The nonwoven webs may also include or be composed of a scrim or netting. The nonwoven webs may comprise nanofibers produce by electrospinning processes and the like. Spunbonded fibers are formed by extruding molten thermoplastic polymer as filaments from a plurality of fine, usually circular capillaries of a spinneret with the diameter of the extruded fibers being rapidly reduced. Meltblown fibers are typically formed by extruding the molten thermoplastic material through a plurality of fine, usually circular, die capillaries as molten threads or filaments into a high velocity, usually heated gas (e.g., air) stream which attenuates the filaments of molten thermoplastic material to reduce their diameter. Thereafter, the meltblown fibers are carried by the high velocity gas stream and are deposited on a collecting surface to from a web of randomly dispersed meltblown fibers. Any of the non-woven webs may be made from a single type of fiber or two or more fibers that differ in the type of thermoplastic polymer and / or thickness.

[0035] Suitable thermoplastic polymeric materials include, but are not limited to, polyolefins (such as polypropylene, or polyethylene), poly(isoprenes), poly(butadienes), chlorinated polymers, polyamides, polyimides, polyethers, poly(ether sulfones), poly(sulfones), poly(vinyl acetates), polyesters such as poly(lactic acid), copolymers of vinyl acetate, such as poly(ethylene) –co-poly(vinyl alcohol), poly(phosphazenes), poly(vinyl esters), poly(vinyl ethers), poly(vinyl alcohols), and poly(carbonates).

[0036] Suitable polyolefins include, but are not limited to, poly(ethylene), poly(propylene), poly(1- butene), poly-4-methyl-1-butene, copolymers of ethylene and propylene, alpha olefin copolymers (such as copolymers of ethylene or propylene with 1-butene, 1-hexene, 1-octene, and 1-decene), poly(ethylene-co-1-butene) and poly(ethylene-co-1-butene-co-1-hexene).

[0037] Suitable polyamides include, but are not limited to, typical nylon polymers such as poly(iminoadipoyliminohexamethylene), poly(iminoadipoyliminodecamethylene), and polycaprolactam. Suitable polyimides include, but are not limited to, poly(pyromellitimide).

[0038] Suitable poly(ether sulfones) include, but are not limited to, poly(diphenylether sulfone) and poly(diphenylsulfone-co-diphenylene oxide sulfone).

[0039] Suitable copolymers of vinyl acetate include, but are not limited to, poly(ethylene-co-vinyl acetate) and such copolymers in which at least some of the acetate groups have been hydrolyzed to afford various poly(vinyl alcohols).

[0040] The fibers selected for the non-woven web depend upon the kind of particulate to be filtered. Particularly useful fibers include webs of meltblown fibers, such as those disclosed in Wente, Van A., "Superfine Thermoplastic Fibers", 48 Industrial Engineering Chemistry, 1342 et seq (1956). Webs of meltblown fibers provide especially good filtration layers when used in a persistent electrically charged form (see U.S. Pat. No. 4,215,682 to Kubik et al). Preferably, these meltblown fibers are microfibers having an effective diameter of at least 4, 6, 8 or even 10 micrometers and at most 12, 14, 16 or even 20 micrometers. Other particularly useful filtration fibers are electrically-charged-fibrillated-film- fibers as disclosed in U.S. Pat. No. RE 31,285 to Van Turnhout. Rosin wool fibrous webs and webs of glass fibers are also useful, as are solution spun, or electrostatically sprayed fibers, especially in microfiber form.

[0041] The non-woven webs are porous, meaning that the outside surface of one side of the non-woven web is in fluid communication with the outside surface on the opposing side of the same non-woven web. This ensures flow of vaporous fluids, air, or liquids through the non-woven web. The non-woven webs are coextensive meaning that the web is a complete, continuous layer of non-woven material with no rips or tears.

[0042] In one embodiment, at least one of the non-woven webs of the present disclosure comprises electret fibers. Electrets are a dielectric material that possess a quasi-permanent electric charge or dipole polarization. Electrets typically are improved by incorporating a charging additive into a polymeric material and then inducing a charge onto the polymeric materials using a corona treatment, a tribocharging treatment, a hydrocharging treatment, or combinations thereof. In one embodiment, the electret fibers are monocomponent fibers. In another embodiment, the electret fibers are bicomponent fibers, such as sheath-core, side-by-side, etc. In one embodiment, the electret fibers are sheath-core fibers comprising a core having a coextensive sheath layer disposed thereon. In one embodiment, the core comprises an electrostatic charge enhancing additive. In one embodiment, the sheath comprises an electrostatic charge enhancing additive. In one embodiment, the electret fibers are side-by-side, wherein the fiber comprises two components lying next to each other along the length of the fiber. In one embodiment, the electret fibers are so called “islands-in-the-sea” extrudates, wherein multiple fiber cores (i.e., more than 1, 2, 4, or even 6 cores) are distributed within a polymer matrix, which also forms the sheath.

[0043] Many charge enhancing additives for making electret-containing fiber webs are known in the art. Exemplary electrostatic charge enhancing additives may include pigments, light stabilizers,primary and secondary antioxidants, metal deactivators, hindered amines, hindered phenols, metal salts, phosphite triesters, phosphoric acid salts, and combinations thereof. Preferably, the charge enhancing additive is a solid at ambient conditions to prevent migration within the resin and does not decompose at moderate temperatures. In one embodiment, the charge enhancing additive is a solid at temperatures of at least 25, 30, 40, 50, 60, 80 or even 100°C. In one embodiment, the charge enhancing additive does not decompose, for example, there is no significant weight loss (i.e., less than 5, 1, or even 0.1 wt %) when measured under nitrogen by thermogravometric analysis using a ramp rate of 10 °C / min to heat up to 235°C.

[0044] Particularly preferred change enhancing additives include hindered amine-based additives, triazine-based additives, and hindered phenol-based additives.

[0045] Specific examples of the hindered amine-based or triazine-based additives include (poly[[6- (l,l,3,3,-tetramethylbutyl) amino]-s-triazine-2,4-diyl][[(2,2,6,6-tetramethyl-4- piperidyl) imino] hexamethylene [(2,2,6, 6-tetramethyl-4-piperidyl) imino]]), available under the trade designation “CHIMASSORB 944” from BASF, Ludwigshafen, Germany; dimethyl succinate-1-(2-hydroxyethyl)- 4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, available under the trade designation “TINUVIN 622” from BASF; di-tert-butyl-4-hydroxybenzyl)-2-n-butyl malonate bis(1,2,2,6,6- pentamethyl-4-piperidyl available under the trade designation “TINUVIN 144” from BASF; a polycondensate of dibutylamine-1,3,5-triazine-N,N′-bis(2,2,6,6-tetramethyl-4-piperidyl-1,6- hexamethylenediamine-N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine, available under the trade designation “CHIMASSORB 2020” from BASF; 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-((hexyl)oxy)- phenol, available under the trade designation “TINUVIN 1577” from BASF; N-substituted amino aromatic compounds, particularly tri-amino substituted compounds, such as 2,4,6-trianilino-p-(carbo- 2'-ethylhexyl-l'-oxy)-l,3,5-triazine, available under the trade designation “UVINUL T-150” from BASF; and 2,4,6-tris-(octadecylamino)triazine, also known as tristearyl melamine ("TSM").

[0046] Hindered phenol-based additives having a hydroxyl group as the terminal functional group. he hindered phenol-based additives are not particularly limited, and specific examples include pentaerythrityl-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (Irganox 1010, manufactured by BASF), octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (Irganox 1076, manufactured by BASF), tris-(3,5-di-tert-butyl-4-hydroxybenzyl)-isocyanurate (Irganox 3114, manufactured by BASF), 3,9-bis-{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)-propionyloxy]-1,1- dimethylethyl}-2,4,8,10-tetraoxaspiro-[5,5]undecane (Sumilizer-GA-80, manufactured by Sumitomo Chemical Co., Ltd.), and the like.

[0047] Additional thermally stable organic triazine compounds or oligomers, which compounds or oligomers contain at least one nitrogen atom in addition to those in the triazine ring, are disclosed in U.S. Patent Nos 6,268,495, 5,976,208, 5,968,635, 5,919,847, and 5,908,598 to Rousseau et al.

[0048] Further examples of charge-enhancing additives are provided in U. S. Publ. No. 2011 / 0137082 (Li et al.). U. S. Pat. Nos. 8613795 (Li et al.), 7,390,351 (Leir et al.), U. S. Pat. No. 5,057,710 (Nishiura et al.), and U. S. Pat. Nos.4,652,282 and 4,789,504, both to Susumu et al., and U. S. Pat. No.8,790,449 B2 (Li et al.).

[0049] The charge-enhancing additive(s) can be added in any suitable amount. The charge-enhancing additives of this disclosure may be effective even in relatively small quantities. Typically, the charge- enhancing additive is present in a thermoplastic resin and charge-enhancing additive blend in amounts of up to about 10 % by weight, more typically in the range of 0.02 to 5 % by weight based upon the total weight of the blend. In some embodiments, the charge-enhancing additive is present in an amount ranging from 0.1 to 3 % by weight, 0.1 to 2 % by weight, 0.2 to 1.0 % by weight, or 0.25 to 0.5 % by weight. Membrane

[0050] Alternatively or additionally, porous membrane may be used in place of, and / or combined with the non-woven fibrous web. The membrane may be a polyolefin porous membrane, a polyacrylonitrile porous membrane, a polycarbonate porous membrane, a polyester porous membrane, a cellulose ester porous membrane, a polyamide porous membrane, a polyethersulfone porous membrane, a polysulfone porous membrane, a polyacrylonitrile nanofiber membrane, cellulose ester nanofiber membrane, a polyvinyl acetate or alcohol nanofiber membrane, a nylon membrane, or a polyvinyl butyral nanofiber membrane.

[0051] The membrane can be made by, for example, TIPS (thermally induced phase separation) process, SIPS (solvent induced phase separation) process, VIPS (vapor induced phase separation) process, stretching process, track-etching, or electrospinning (e.g., PAN fiber membranes).

[0052] A membrane may be wrinkled, for example, using the techniques described herein above with respect to FIGS. 1-2. In some embodiments, the plurality of elastic fibers or filaments are positioned between a membrane layer and one or more non-woven porous webs. However, it is expressly contemplated that, in some embodiments, the plurality of elastic fibers or filaments are positioned between a first membrane layer and a second membrane layer, which may have the same or different composition. The membrane layer may include membrane and one or more non-woven webs stacked or laminated or bonded.Non-woven Porous Webs Containing Sorbent Particles

[0053] Non-woven webs and porous structures containing a sorbent material or multiple sorbent materials have been employed for a variety of uses such as respirators and furnace filters for the removal of gases and vapors contaminants, and vacuum cleaner bags. There are various methods making them such as those used in preparing Examples 1 and 12 in US Pat. No. 6,234,171 B1 (Springett et al), or those described in U.S. Pat. No. 7,354,475 B2 (Von Blucher), or those described in U.S. Pat. No.5,662,728 A (Gunter). The sorbent particles may be distributed throughout the depth of non-woven porous web, or substantially disposed on the surface of non-woven web, or, or immobilized within a stable 3D framework. One example of the sorbent material is activated carbon.

[0054] Activated carbon, i.e., an active or functional particulate having sorptive properties, is widely used to filter air to remove at least a portion of a variety of gases and vapors, including industrial chemicals, solvents, and odorous compounds. Adsorption typically occurs in the micropores but in some cases can also occur in the meso and macropores (as defined by IUPAC) Activated carbon is derived, for example, from coal or coconut shells and can be produced in the form of powders, granules, and shaped products. In addition, they can be modified by the addition of acid, bases or metals to remove a plethora of targeted gases or vapors.

[0055] In addition to activated carbon, there are other porous sorbent structures that can be useful for separating components in gas and liquid streams or for purifying such streams. Examples of other porous sorbent structures include silica gel and activated alumina. Other sorbents include crystalline aluminosilicates or zeolites or molecular sieve adsorbents and metalorganic framework (MOFs). Other sorbent materials can also be functionalized polymeric sorbents as described in US 10,780,416 B2.

[0056] Various filters can include active or functional particulate materials that interact with fluids by sorbing (adsorbing or absorbing) components from the fluids. The sorbent materials can add additional performance characteristics to overall filter capabilities. They can be incorporated into a layer of a sorbent-carrying or sorbent-loaded nonwoven web and be added to one or more layers of particulate filter media to aid in removing the gas and vapor contaminants from the ambient air. Common respirators that provide at least a minimal level of protection typically include a layer or layers of carbon-loaded meltblown microfibers along with one or more particulate filter layers. For example, respirators can include microporous sorbents that purify workplace breathing air. Other examples include heating, ventilation, and / or air conditioning (HVAC) equipment filter; a portable air purifier filter; an air conditioning device filter; a portable fan filter; or a vent filter.

[0057] Sorbent particles can be graded to a nominal screened grade using U. S.A. Standard Test Sieves conforming to ASTM D2862 "Standard Test Method for Particle Size Distribution of Granular Activated Carbon ". ASTM D2862 prescribes the requirements for the design and construction oftesting sieves using a medium of woven wire cloth mounted in a frame for the classification of materials according to a designated particle size. A typical designation may be represented as 12x20 meaning that the particles pass (in this case sorbent) through a test sieve meeting ASTM D-2862 specifications for the number 12 sieve and are retained on a test sieve meeting ASTM D-2862 specifications for the number 20 sieve. In one embodiment, the sorbent particles have a particle size such that most of the particles pass through a 12 mesh test sieve and some of the particles can be retained on a 14, 16, 18, or 20 mesh test sieve. The distribution of the particles on each sieve will be designed for optimum performance. In various embodiments, the particles can have a nominal screened grade of:4X8, 8X16, 12X2016X35, 20X45, 30X60, 40X140 or 80X325. Alternatively, a custom mesh can be used from any range of 4X8 to 300X620. Method of Making

[0058] In one embodiment, the wrinkled filter media of the present application can be made by stretching a first series comprising a plurality of elastic fibers or filaments. The fibers or filaments are not generally bonded to one another (for example, the fibers or filaments of the present disclosure are not a scrim). The plurality of elastic fibers or filaments in the first series are held (for example using a spacer) such that each of the fibers or filaments is substantially parallel to one another and are spaced a given distance apart. Generally, the substantially parallel fibers or filaments should not touch the nearest neighbor fibers or filament in the working portion of the finished good. In one embodiment, the elastic fibers or filaments are held with a spacing of at least 2, 4, 5, or even 6 fibers or filaments per inch. In one embodiment, the elastic fibers or filaments are held with a spacing of at most 8, 10, 12, 15, 20, or even 25 filaments per inch. Generally, the spacing of the fibers or filaments is selected to achieve the desired shirring of the non-woven web without causing a large change in pressure.

[0059] Shown in FIG.3 is exemplary configuration of a first series of fibers 32, wherein the fibers are tied at either end and combs 35 and 37 are used at both ends to hold the fibers substantially parallel. The first series of fibers are placed between first non-woven porous fibrous web 34 and second non- woven porous fibrous web 36. Either one or both of the non-woven porous webs 34 and 6 may contain sorbent particles. Nonwoven web 36 is placed below the stretched plurality of parallel fibers with the adhesive side contacting the fibers. The second adhesive-sprayed web 34 is placed above the stretched plurality of parallel fibers with the adhesive side contacting the fibers. An additional and optional non- woven or woven porous web can be sprayed with adhesive and be placed onto the above laminate. Then, a cardboard roller compresses the laminate gently to remove any air pockets so that the nonwoven and / or woven webs were adhered together with the filaments positioned in between the webs. The manual hold of the stretched plurality of parallel fibers is then released, and the filamentsare allowed to relax causing the laminated media (web-adhesive-fibers-adhesive-web-optional adhesive-web) to pucker. Additional details of how wrinkled media can be made can be found in US Provisional Patent Application 63 / 434365, filed December 21, specifically in paragraphs [0027-0037], which are incorporated herein by reference.

[0060] The fibers or filaments can be stretched to a desired length preferably before they reach the elastic limit or yield point. The % stretch as used herein is defined as the difference between the length of the stretched fiber or filament and the length of the initial relaxed fiber or filament divided by the length of the initial relaxed fiber or filament converted to a percent. In one embodiment, the elastic fibers are stretched to between 50 and 250%. The fibers or filaments can be stretched more than 250% so long as the fibers or filaments do not go beyond the elastic limit to deformation or break during the manufacturing of the wrinkled media disclosed herein.

[0061] The first and second non-woven webs are positioned on either side of the stretched filaments. The first and second non-woven webs may be the same or different. The non-woven webs are selected based on the desired performance properties. The non-woven webs selected may be different in terms of composition, basis weight, thickness, porosity, etc. One or both webs contain sorbent particles. A third non-woven or woven web can be positioned on top of either the first or the second web.

[0062] The first and second non-woven webs are bonded directly together such that the first non- woven web contacts the second non-woven web, optionally with the use of an adhesive as exemplified below. In one embodiment, an adhesive is used to directly bond (or adhere) the first and second non- woven webs together. Such adhesives can include a pressure sensitive adhesive or a hot melt adhesive. Pressure sensitive adhesives are known in the art and are generally adhesives that can adhere based on room temperature conditions when pressure (e.g., finger pressure) is applied. Exemplary pressure sensitive adhesives include: a natural latex or synthetic polymer such as a (meth)acrylate. A commercially available pressure sensitive adhesive includes a spray adhesive available under the trade designation “3M Super 77 Multipurpose Adhesive” by 3M Company, Maplewood, MN, USA. Hot melt adhesives are those adhesives that are thermoplastic polymers which are heated above their softening point and when applied in their softened state to a surface, penetrate the surface and solidify ensuring cohesion. Exemplary hot melt adhesives include: Bostik HM-9041 available from Bostik inc., Wauwatosa, WI, and Tailored HM011BA available from Tailored Chemical Products Inc., Hickory, NC. In the embodiments of the present application when an adhesive is applied, the weight of adhesive used per unit area is less than the weight per unit area of the non-woven web. In one embodiment, the weight per unit area of the adhesive is less than 0.5, 0.4, 0.3, 0.2, or even 0.1 % of the weight per unit area of the non-woven porous fibrous webs in the article. Ideally, the adhesive should not interfere with the performance of the article and should be collapsible, meaning that theadhesive can maintain cohesiveness (or keep the two layers of non-woven webs bonded) upon the relaxing of the stretched fibers or filaments during manufacture. In one embodiment, the adhesive is at least 1, 2, 4, 5, or even 6 gsm (grams per square meter) in the wrinkled article. In one embodiment, the adhesive is at most 8, 10, 15, 20, 40, 60, 80 or even 100 gsm in the wrinkled article. In another embodiment, the first and second non-woven webs are welded directly together such that the first non- woven porous fibrous web is in intimate contact with the second non-woven porous fibrous web. Such welding techniques are known in the art and include thermal bonding or ultrasonic welding.

[0063] After bonding (or adhering) the first and second non-woven porous fibrous webs together, the tension is released on the stretched elastic fibers or filaments and the resulting article puckers or becomes shirred as represented schematically in FIG.1. Typically, after the tension is released on the stretched elastic fibers or filaments, it could take upwards of hours or days for the shirred article to achieve its final puckered state as an equilibrium in the construction is reached. In one embodiment, the heat can be used to more quickly achieve this stable state.

[0064] In making the wrinkled sorbent containing webs, if adhesive is used, the selection of adhesive is important. It is highly preferred that the adhesive has no or very low organic content such as solvent or other off-gases so that it has no or minimal adverse impact on carbon particles’ adsorptive capacity. Also, it should not substantially clog activated carbon particles’ pores for adsorption path. Thirdly, it should bond non-woven webs, sorbent particles, and sorbent particles to elastic fibers well.

[0065] The amount of adhesive used in wrinkled media is also important. There should be adequate adhesion to bond the webs, particles, and elastic fibers, but should have minimal impact on non-woven web’s pressure drop and filtration efficiency. Too little amount of adhesion bonds the materials poorly. Too much adhesive can cover sorbent particles to limit access to adsorption pores, block filtration surface area of non-woven web, and make media more rigid and less stretchable.

[0066] Additionally, the adhesive needs to either cure quickly or be applied ahead of time to minimize the detachment of webs or elastic fibers from the webs or sorbent particles before tension on elastic fibers is released. The local detachment may result in air pockets and no puckering to result in less uniformly formed wrinkles in media.

[0067] When other bonding means such as ultrasonic welding are used in place of adhesive, sorbent particle sizes and distribution withing non-woven webs, elastic fiber size and spacing, and stretch ratio should all be considered for a better and more uniform bonding and puckering in wrinkling process.

[0068] For non-woven webs with high particle load level, it is common that particles can come off the webs or become loose upon handling such as bending, stretching, and compressing. When particle loss or movement happens, it leads to loss of torturous path around carbon particles for nuisance gases and vapors that result in less adsorption and much shorter service life. This may be more apparent withnon-woven webs loaded with larger sorbent particles. To minimize sorbent particle loss and movement during wrinkling process, appropriate elastic fiber size, spacing and stretch ratio need to be selected and used. Too large of elastic fiber size and spacing may lead to uneven or non-uniform puckering that causes particle twist or detach or move and eventually particle concentrating locally or even lose. Too high of stretch ratio may lead to more particle and web bundling and increase of pressure drop. Too small of elastic fibers and / or too low of stretch ratio may lead to longer relaxation time and low stretchability.

[0069] The large sorbent particles in non-woven web may present additional challenges where they may push through or damage the non-woven webs when they are under pressure in lamination during wrinkling process.

[0070] In addition to the first and second non-woven webs, additional layers (e.g., a third layer) maybe added to the shirred article to provide additional functionality. The third non-woven or woven layer may be added before release of the tension on the fiber or filaments, such that the third layer is also puckered or shirred. In another embodiment, the third layer is added after release of the tension on the fibers or filaments, such that the third layer is a flat layer bonded to the puckered or shirred article. Exemplary third layers include cover webs, which is a layer used to protect the underlying article from abrasion, soiling, etc. The third layer may also provide cosmetic and visual function.

[0071] In another embodiment, in addition to the first series of elastic fibers or filaments, a second series of fibers or filaments can also be used, wherein the first and second series of elastic fibers or filaments are positioned non-parallel to each other (for example at least 45 degrees or at least 90 degrees apart). The shirred article is made as described above, except that both series of elastic fibers or filaments are placed between the two non-woven webs. When tension is released on both series of fibers or filaments, the resulting article has a more complex puckered pattern as shown in the Example Section.

[0072] In yet another embodiment, the series of elastic fibers or filaments may be stretch to different percentages, such that when the tension is released the resulting puckered material comprises areas with more puckering and areas with less puckering.

[0073] The articles of the present disclosure are resiliently extensible under tension, meaning that when the puckered article is pulled in the same direction as the length of the elastic fibers or filaments, the puckered article can elongate (or flatten out) and when the tension is released, the elongated article returns to its puckered form. In one embodiment, the puckered article is elastically extensible to at least 2 or even 3 times of its relaxed length. In some embodiments, the puckered article comprises at least one portion which is resiliently extensible under a first tension, wherein a second portion of the shirred filter media is under a second tension.

[0074] Because the articles of the present disclosure have a puckered (or shirred) appearance, the basis weight of the resulting article has a higher basis weight than the original flat or unwrinkled non-woven porous fibrous webs. In one embodiment, the shirred articles of the present disclosure have a basis weight of at least 20, 30, 40, 50, 100, or even 200 grams per square meter (gsm). In one embodiment, the shirred articles of the present disclosure have a basis weight of at most 200, 300, 400, 500, 600, 800, 1000, or even 1500 gsm.

[0075] The resulting shirred media is self-supporting meaning that an addition layer is not needed to provide support to the non-woven web / fiber or filament / non-woven web construction, optionally comprising an adhesive. Such articles can be used to filter out undesirable particles from the fluids, such as dust, molds, oily mist aerosol, cigarette smoke, pet dander, viruses, bacteria, etc.

[0076] Filtration performance test results of shirred media articles with no sorbent particles are discussed in greater detail in US Provisional Patent Application 63 / 434365, filed December 21, specifically in the Examples, which are incorporated herein by reference. Test Methods

[0077] The following test methods were used to evaluate media examples. A minimum of two samples were tested and averaged for each Example (EX) and Comparative Example (CE) unless otherwise specified.

[0078] Unless otherwise noted, all initial NaCl penetration and pressure drop tests for webs were run at a face velocity o.f 13.9 cm / sec. The listed media web performance in Tables 2 and 3 are actual measurements per Test Methods listed. NaCl Initial Tests and Quality Factor:

[0079] Pressure drop and percent penetration of respirators may be determined using a challenge containing NaCl particles, delivered at a flow rate of 85 liters / min or LPM, and evaluated using a TSI™ Model 8130 high-speed automated filter tester (available from TSI Inc., Shoreview, Minnesota). An MKS pressure transducer (available from MKS Instruments, Andover, Massachusetts) may be employed to measure pressure drop (dP, mm H2O) through the filter media or filter samples.

[0080] For NaCl instantaneous testing at 85 liters / min (i.e. LPM) and using 0.075 µm diameter particles, the particles may be generated from a 2% NaCl solution to provide an aerosol containing particles at an airborne concentration of about 16-23 mg / m3, and the Automated Filter Tester may be operated with both the heater and particle neutralizer on. The NaCl initial penetration and pressure drop tests last about 19 seconds.

[0081] The NaCl particles are forced through a media sample that has 11.4 cm in diameter or 102 cm2opening at a rate of 85 LPM.

[0082] The NaCl percent penetration is defined by the following formula: %Pen = (Concentration downstream / Concentration upstream) x100 Equation 1

[0083] The NaCl percent penetration and pressure drop are used to calculate a quality factor “QF” by the following formula: ^^^^ ^1ൗ ^^^^^^ଶ^^ ^ ൌି୪୬ ^%^^^ / ^^^^ ^^^^^௨^^ ^^^^ ^^^ுమை^ Equation 2

[0084] A filtration performance. Decreased QF valuesOrganic Vapor (OV) Adsorption Test:

[0085] The organic vapor test system has air flow rate (13.1 or 20 LPM) controlled by a Brooks mass flow meter and controller (from Brooks Instrument at 407 West Vine Street, Hatfield, PA, USA) and validated using a TSI flowmeter model 4040 (from TSI Incorporated at 500 Cardigan Road, Shoreview, MN, USA). The relative humidity in air stream (50%) was introduced from a water pot and controlled by a customized PID (Proportional-Integrao-derivative) controller. N-Hexane, selected as the OV gas, was then added to the air stream by volatizing n-hexane on a heater. Liquid n-hexane was delivered using a Harvad syringe pump (from Harvard Apparatus, 84 October Hill Road, Holliston, MA 01746, USA). The n-hexane challenge concentration was 60 ppm. The challenge gas (60 ppm hexane in humid air) was then passed across the filter. The effluent stream was then measured for hexane using a gas chromatogram (GC) equipped with a flame ionize detector supplied by SRI GC (SRI Instruments 20720 Earl St. Torrance, CA 90503. The effluent organic vapor concentration was measured at an approximate interval of 2 minutes using the SRI GC-FID analyzer throughout the test until after breakthrough concentration was reached. The time it took to reach breakthrough concentration (5 ppm) is the service life of the sorbent loaded media. The higher adsorption capacity the sorbent loaded media has, the longer its service life is. Acid Gas (AG) Adsorption Test:

[0086] The sulfur dioxide (SO2) system has air flow rate (20 LPM) controlled by a rotameter and validated using a TSI flowmeter model 4040 (from TSI Incorporated at 500 Cardigan Road, Shoreview, MN, USA). The relative humidity in air stream (50%) was introduced from a water pot and controlled by a customized PID (Proportional-Integrao-derivative) controller. SO2 was then added to the air stream using a gas cylinder containing anhydrous SO2and controlled using a Brooks Mass Flow Controller (from Brooks Instrument at 407 West Vine Street, Hatfield, PA, USA). The SO2concentration was 50 ppm. The challenge gas (50 ppm hexane in humid air) was then passed across the filter. The effluent stream was then measured for hexane using a SO2Interscan. The effluent organic vapor concentration was measured at an approximate interval of 5 seconds using the Interscan analyzer (obtained from Interscan Company 1554 NE 3rd Ave, Camas, WA 99607) throughout the test until after breakthrough concentration was reached. The time it took to reach breakthrough concentration (5 ppm) is the service life of the sorbent loaded media. The higher adsorption capacity the sorbent loaded media has, the longer its service life is. Formaldehyde (HCHO) Adsorption Test:

[0087] The HCHO test system has air flow rate (32 LPM) controlled by a Brooks mass flow meter and controller (from Brooks Instrument at 407 West Vine Street, Hatfield, PA, USA) and validated using a TSI flowmeter model 4040 (from TSI Incorporated at 500 Cardigan Road, Shoreview, MN, USA). The relative humidity in air stream (50%) was introduced from a water pot and controlled by a customized PID (Proportional-Integrao-derivative) controller. Formaldehyde water solution free of methanol with a certified 10% HCHO weight concentration (from Polysciences Inc. at 400 Valley Road, Warrington, PA 18976, USA) was used with its concentration verified through titration. The HCHO solution was diluted to 1% for tests.

[0088] During testing, the diluted 1% HCHO solution is delivered by a Harvard syringe pump (from Harvard Apparatus, 84 October Hill Road, Holliston, MA 01746, USA) onto a temperature controlled hot plate and immediately evaporated off into the incoming air stream. The mixed air stream containing HCHO then entered the test chamber where the sorbent loaded filter media was mounted. The influent concentration of HCHO was periodically verified with direct measurements by a photoacoustic IR analyzer Innova 1512 (from LumaSense Technologies A / S, Energivej 30, 2750 Ballerup, Denmark). The effluent HCHO concentration was measured at an approximate interval of 40 seconds using the Innova 1512 analyzer throughout the test until after breakthrough concentration was reached. The time it took to reach breakthrough concentration (1 ppm) is the service life of the sorbent loaded media. The higher adsorption capacity the sorbent loaded media has, the longer its service life is.

[0089] Wrinkled media, as described in FIGS. 1-3, may be used as a filter media for respiratory protection. For example, wrinkled media may be useful in disposable respirators, to form one or more layers of a respirator body, or in reusable respirators, to form a layer or a portion of a pleat pack. These, and other examples, are discussed in greater depth in US Provisional Patent Application Ser. Nos. 63 / 496002 and 63 / 496003, both filed April 13, 2023. (cite WM Respirator case).

[0090] Wrinkled media may also be useful for improving the fit of a respirator. Because wrinkled media is stretchable and resilient, it can conform to different face shapes and sizes. Fit features, e.g. features added to a respirator body to improve fit, may also have lower contact pressure with the same or higher level of filtration performance as the respirator media. In some embodiments herein, respirators contain one or more fit features. The fit features may be formed from sorbent-free wrinkled media in such embodiments.

[0091] Fit features made of wrinkled media may act as a spacer to help a respirator fit better to a number of facial features – e.g. narrower or shorter faces. The stretch may also help to maintain fit of a respirator while a user changes facial expressions or move their head.

[0092] Fit features formed of wrinkled filter media also increase a filter area of the respirator. The increased filter area may reduce an ambient temperature inside a respirator (which is generally warmer than ambient air due to the wearer’s exhaled breath).

[0093] Fit features herein are illustrated with respect to a few example respiratory styles in the Figures herein. However, it is expressly contemplated that fit features described herein may be modified to fit any number of respirator styles, such as any of those described or illustrated in US Provisional Patent Application Ser. No.63 / 496002, filed April 13, 2023, which is incorporated herein by reference in its entirety.

[0094] Fit features may include nose pads and / or face shields, as described in FIGS. 4-7 of US Provisional Patent Application Ser. No.63 / 496002, filed April 13, 2023, which, along with the relevant description, is incorporated herein by reference.

[0095] FIG. 4 illustrates a method of making a respiratory protection device in accordance with embodiments herein. Method 400 may be used to form respirators of any disposable respirator model that could benefit from a nose pad or face seal as described herein.

[0096] At block 410, respirator media is obtained. Wrinkled media 412 such as F2 web, described in the Examples below, may be obtained for one or more layers or panels of a respirator, and serve as a respirator filter layer. Respirator media may include a face seal layer, in some embodiments. Respirator media may also include a nose pad layer, in some embodiments. In accordance with embodiments herein, one or more layers or panels of a respirator include sorbent-loaded media 802. However, it is expressly contemplated that other media, such as sorbent-free wrinkled media or flat media, may be used for some layers. For example, a fit feature layer may be formed from sorbent-free wrinkled media.

[0097] Flat media 414 may be formed from one or more layers or panels. Other media 416 may also be used. For example, media with anti-fog properties may be obtained for a portion of the respirator. Alternatively, a shell layer may be obtained to use as a shell, for cup-shaped respirators, for example.

[0098] At block 420, one or more treatments are performed on one or more of the layers. For example, a cup shell may be pre-formed 422. One or more layers may be charged 424 to exhibit electret properties attracting and binding particulates and liquid droplets. Other treatments 426 may be performed.

[0099] A preform step, required for cup-shape respirators, can be a rate-limiting step in the manufacture of respirators as curvature must be formed in multiple directions, which may include cutting and welding in a sinusoidal shape. It is noted that some embodiments herein using a dashed- line slitted layer (sometimes referred to as a skip slit layer) to form the cup-shape structure do not require a preform step.

[0100] A dashed-line slitted layer is composed of a surface that has been cut through (e.g. slit) in a dashed-line pattern. US PAP 2019 / 0187345 describes and illustrates a number of patterns that may be used in embodiments herein. The slit pattern may be a diamond slit pattern, for example as illustrated in FIGS.1-4 and 12 of US 2019 / 0187345, incorporated herein by reference. The slit pattern may also have non-diamond slit patterns that also allow for expansion in at least one direction, for example as illustrated in FIGS. 5, 8, 10, 11 and 14, of US2019 / 0187345, incorporated herein by reference. The slit pattern may also have two different size or shape openings, as illustrated in FIGS. 6 and 15 of US 2019 / 0187345, incorporated herein by reference. The slit pattern may also have three different size or shape openings, as illustrated in FIGS.7, 9 and 13 of US 2019 / 0187345, incorporated herein by reference. The slit pattern may also have two different size or shape openings that allow expansion in two directions as illustrated in FIGS. 16 and 18 of US 2019 / 0187345. The slit pattern may also have three different size or shape openings that converge to provide expansion in at least three directions, as illustrated in FIG.19 of US2019 / 0187345.

[0101] However, other shell solutions may also be used. In some embodiments, an elastic net may be used as a shell. An elastic net may be formed by molding, extrusion, or another suitable method.

[0102] At block 430, a layer stack is formed. The layer stack may be composed of one or more filter layers 432. Filter layers 432 may be wrinkled media and / or flat media layers. The layer stack 432 may include a face seal layer, as described in U.S. Provisional Application No.: 63 / 610,995. The face seal layer may have a pre-formed inner diameter from a previous cutting step (not shown). The layer stack 432 may also include a nose pad layer as described in U.S. Provisional Application No.: 63 / 610,995. The layer stack may include a cover web 434. The layer stack may include a shell 836, such as a skip-slit shell, a corrugated shell, or another suitable shell component. The layer stack may include a layer 838 with sorbent incorporated that can adsorb or absorb gases, vapor, etc. The sorbent may be any suitable sorbent, such as those discussed above. Other layers 439 maybe present such as fluid resistant layers or stiffening layers.

[0103] At block 440, the layer stack is sealed. Sealing the layer stack may include applying a weld 442, seam 444, bond 446 or other suitable method 448 to couple two or more layers of respirator media. Additionally, while a weld 442 or bond 444 are illustrated, it is expressly contemplated that these may not be complete – e.g. a dashed or point weld or bond may be used in embodiments herein, which would allow for stretching along the sealed edge. Similarly, the stretching along the sealed edge is desired, a seam 844 may include an elastic fiber or filament. The sealing occurs such that each layer is in intimate contact with adjacent layers. Suitable welding techniques are known in the art and include thermal bonding or ultrasonic welding.

[0104] In some embodiments, sealing a layer stack includes sealing a nose pad to a layer of respirator media. Sealing the nose pad may occur in the same sealing step as the respirator filter media layer(s), a subsequent step, or as a step prior to sealing 440.

[0105] At block 450, accessories are added. A nose clip 452 may be applied. The nose clip may serve to mold a respirator so that a seal forms with a wearer’s face along the nose portion of the racetrack. The nose clip 452 may include a moldable metal or plastic strip or other suitable mechanism. The nose clip may be applied before or after a layer stack is sealed, for example such that it is not visible on an exterior or interior of the respirator.

[0106] A nose cushion 454 may also be added to increase comfort and improve seal. For example, custom nose cushions are described in PCT Publication WO 2022 / 235472, published on November 10, 2022, however other foam types and positions are expressly contemplated.

[0107] An exhalation valve 456 may be added. In some embodiments, a valve-containing portion of a respirator has less stretch than a valve-less portion. A harness 458, for holding the respirator in contact with a wearer’s face, may be applied. In some embodiments, the harness 458 includes straps or earloops that are integral to a wrinkled media layer of the respirator. In some embodiments, the harness 458 is a separate component welded, stapled, adhered or otherwise coupled to the respirator body. Other accessories 459 may also be added.

[0108] Other crush-resistance features may be present to assist in maintaining a respirator shape before and during wear. For example, U.S. Pats. No. 6,923,182 B2, issued August 2, 2005; 8,640,704, issued February 4, 2014; and U.S. Pat.6,394,090, issued May 28, 2002; all describe features to improve structural integrity of a respirator body before and during use which may be used in accordance with embodiments herein.

[0109] In some embodiments herein, a horizontal flat-fold respirator is provided with one or more sorbent layers. A horizontal flat-fold respirator is a respirator formed of three panels – a top panel that engages a wearer’s nose, a bottom panel that engages a wearer’s chin, and a central panel that extends between the top panel and the bottom panel. The top panel is joined to the central panel alonga perimeter of the central panel, through either a fold-line, seam, weld or bond, said fold-line, seam, weld or bond of said first panel being substantially coextensive with an edge of said central panel. The bottom panel has an edge defined by a perimeter joined to the central panel through a fold-line, seam, weld or bond, said fold-line, seam, weld or bond of said second panel being substantially coextensive with an edge of said central panel. Respirators of this type may be capable of being folded flat for storage and, during use, but are capable of forming a cup-shaped air chamber over the nose and mouth of the wearer. This design of respirator may commonly be referred to as a trifold respirator, a three- panel respirator, a flat-fold respirator, or a horizontal flat-fold respirator, all of which may be used interchangeably.

[0110] In some embodiments herein, a cup-style respirator is provided with one or more fit features. A cup-style respirator may include a respirator filter layer formed around or to a shell.

[0111] Other respirator styles with one or more fit features are also envisioned in accordance with embodiments herein, such as a vertical-fold style respirator, a pleated style respirator, such as that illustrated in US Pat. No.8,640,704, FIGS.1-4 and column 4, line 25 – column 5, line 29, incorporated herein by reference, a duck-bill style respirator, such as that described in U.S. Pat 5,322,061 to Brunson.

[0112] While respirators herein are illustrated as having white fibers or filaments in the wrinkled media, it is expressly contemplated that naturally colored, or dyed filaments may be used – for example to visually differentiate models of respirators.

[0113] Disposable respirators composed of different layers or panels are generally sealed along a perimeter of the respirator to ensure that air is forced through the filter material. Often the seal is made using welding, bonding or stitching a seam. Some embodiments herein, however, are sealed using point-welding or point-bonding, in some embodiments, to create a sufficient seal while allowing the respirator to stretch. Some embodiments use an elastic fiber or filament to form the seam, such that the elastic fiber or filament can stretch with the wrinkled media.

[0114] Foreseeable modifications and alterations of this invention will be apparent to those skilled in the art without departing from the scope and spirit of this invention. This invention should not be restricted to the embodiments that are set forth in this application for illustrative purposes. To the extent that there is any conflict or discrepancy between this specification as written and the disclosure in any document mentioned or incorporated by reference herein, this specification as written will prevail.

[0115] A sheet of wrinkled filter media includes a first series of substantially parallel non- bonded elastic fibers or filament between a first non-woven porous web and a second non-woven porous web, the first non-woven porous web includes a sorbent material, the sorbent material includessorbent particles having a mesh size between about 4x8 and 300X635. The first non-woven porous web is directly bonded to the second non-woven porous web. At least one portion of the wrinkly media is resiliently extensible under tension.

[0116] The sheet may be implemented such that the sorbent material is primarily a micro or meso porous adsorbent.

[0117] The sheet may be implemented such that the sorbent material includes activated carbon.

[0118] The sheet may be implemented such that the sorbent material is a chemically treated activated carbon.

[0119] The sheet may be implemented such that the sorbent material is a microporous polymer.

[0120] The sheet may be implemented such that the sorbent material is designed to remove organic vapor, acid gases, basic gases, formaldehyde, ammonia, mercury vapor, or a combination of few.

[0121] The sheet may be implemented such that the sheet has a longer n-hexane service-life than a sheet of flat media containing the same sorbent material when tested at a 13.1 or 20 liters per minute flow rate, with a 60 ppm n-hexane challenge concentration, 50% relative humidity, and 5 ppm breakthrough.

[0122] The sheet may be implemented such that the n-hexane service life is more than 20% longer than the sheet of flat media containing the same sorbent material.

[0123] The sheet may be implemented such that the n-hexane service life is more than 50% longer than the sheet of flat media containing the same sorbent material.

[0124] The sheet may be implemented such that the service life is more than 20% longer after being stretched and recovered 50 times.

[0125] The sheet may be implemented such that the service life is more than 50% longer after being stretched and recovered 50 times.

[0126] The sheet may be implemented such that the first non-porous web includes polypropylene.

[0127] The sheet may be implemented such that, the activated carbon particles are on a surface of the first nonwoven porous web.

[0128] The sheet may be implemented such that the sheet has at least a 50% adsorptive capacity increase compared to the sheet of flat media.

[0129] The sheet may be implemented such that the sheet has at least a 40% pressure drop reduction when compared to the sheet of flat media.

[0130] The sheet of may be implemented such the service life is more than 20% longer after being stretched and recovered 50 times.

[0131] The sheet may be implemented such that, when compared to a flat sheet of media having the same composition and initial basis weight, the sheet has a lower pressure drop.

[0132] The sheet may be implemented such that the sheet has a longer formaldehyde service- life than a sheet of flat media containing the same material when tested at a 32 liters per minute flow rate, at a 50 ppm formaldehyde concentration, 50% relative humidity and 5 ppm breakthrough.

[0133] The sheet may be implemented such the formaldehyde service life is more than twice as long.

[0134] The sheet may be implemented such the formaldehyde service life is more than three times as long.

[0135] The sheet may be implemented such that the sorbent material includes silica gel, activated alumina, crystalline aluminosilicates, or zeolites.

[0136] The sheet may be implemented such that the sorbent material includes molecular sieve adsorbents or metalorganic frameworks.

[0137] The sheet may be implemented such that the sorbent material includes a functionalized polymeric sorbent.

[0138] The sheet may be implemented such that the sorbent material includes active carbon.

[0139] The sheet may be implemented such the activated carbon is derived from coal or coconut shells.

[0140] The sheet may be implemented such the activated carbon is deposited as a powder, a granule or a shaped product.

[0141] The sheet may be implemented such that the second nonwoven porous web includes a second sorbent material.

[0142] The sheet may be implemented such the second sorbent material differs from the sorbent material.

[0143] A disposable respirator containing a sorbent media includes a layer of wrinkled media. The wrinkled media includes: a first series of substantially parallel non-bonded elastic fibers or filaments between a first nonwoven porous web and a second nonwoven porous web, the first non- woven porous web includes a sorbent material, the sorbent material includes sorbent particles having a mesh size between about 4x8 and 300X635, and the first non-woven porous web is directly bonded to the second non-woven porous web. At least one portion of the wrinkled media is resiliently extensible under tension. The layer of wrinkled media is formed into the disposable respirator.

[0144] The respirator may be implemented such that the disposable respirator is a horizontal flat-fold style respirator.

[0145] The respirator may be implemented such that the disposable respirator is a cup-shape style respirator, and the cup-shape respirator includes a shell.

[0146] The respirator may be implemented such that the disposable respirator is a vertical-fold style respirator.

[0147] The respirator may be implemented such that the disposable respirator is a pleated style respirator.

[0148] The respirator may be implemented such that the disposable respirator is a duck bill style respirator.

[0149] The respirator may include: a nose clip, a foam layer, a valve, or a harness.

[0150] The respirator may include a strap, and the strap, in combination with the layer of wrinkled media, forms a unitary wrinkled media article.

[0151] The respirator may be implemented such that one of the first and second nonwoven layers includes a membrane.

[0152] The respirator may be implemented such that one of the first and second nonwoven layers includes a fibrous nonwoven material.

[0153] The respirator may be implemented such that the respirator is configured to remove gas and vapor air contaminants.

[0154] The respirator may be implemented such that the respirator is configured to remove organic vapors, acid gases, base gases, ozone, or formaldehyde.

[0155] The respirator may be implemented such that the sorbent material is primarily a micro or meso porous adsorbent.

[0156] The respirator may be implemented such that the sorbent material includes activated carbon.

[0157] The respirator may be implemented such the sorbent material is a treated activated carbon.

[0158] The respirator may be implemented such that the sorbent material is a microporous polymer.

[0159] The respirator may be implemented such that the wrinkled media has a longer n-hexane service-life than a sheet of flat media having the same composition and containing the same sorbent material when tested at a 20 liters per minute flow rate, with a 60 ppm n-hexane challenge concentration, 50% relative humidity, and 5 ppm breakthrough.

[0160] The respirator may be implemented such the n-hexane service life is more than 20% longer than the sheet of flat media containing the same sorbent material.

[0161] The respirator may be implemented such the n-hexane service life is more than 50% longer than the sheet of flat media containing the same sorbent material.

[0162] The respirator may be implemented such the service life is more than 20% longer after being stretched and recovered 50 times.

[0163] The respirator may be implemented such the service life is more than 50% longer after being stretched and recovered 50 times.

[0164] The respirator may be implemented such the first non-porous web includes polypropylene.

[0165] The respirator may be implemented such the sheet includes activated carbon particles are on a surface of the first nonwoven porous web.

[0166] The respirator may be implemented such that the sorbent material includes silica gel, activated alumina, crystalline aluminosilicates, or zeolites.

[0167] The respirator may be implemented such that the sorbent material includes molecular sieve adsorbents or metalorganic frameworks.

[0168] The respirator may be implemented such that the sorbent material includes a functionalized polymeric sorbent.

[0169] The respirator may be implemented such the activated carbon is derived from coal or coconut shells.

[0170] The respirator may be implemented such the activated carbon is deposited as a powder, a granule or a shaped product.

[0171] The respirator may be implemented such that the second nonwoven porous web includes a second sorbent material.

[0172] The respirator may be implemented such the second sorbent material has a different composition from the sorbent material.

[0173] The respirator may be implemented such the second sorbent material includes the sorbent particles having a mesh size between about 8x16 and 80x325.

[0174] A horizontal flat-fold respirator includes a layer of wrinkled media, the wrinkled media includes: a first series of substantially parallel non-bonded elastic filaments between a first nonwoven porous web and a second nonwoven porous web, the first non-woven porous web includes a sorbent material, the sorbent material includes sorbent particles having a mesh size between about 4x8 and 300x620. The first non-woven porous web is directly bonded to the second non-woven porous web. At least one portion of the wrinkled media is resiliently extensible under tension.

[0175] The respirator may be implemented such that the respirator further includes: a top panel configured to seal around a nose of a user, a bottom panel configured to seal around a chin of a user, acenter panel, the center panel includes a top edge and a bottom edge, the center panel seals to the top panel along the top edge, the center panel seals to the bottom panel along the bottom edge.

[0176] The respirator may be implemented such that the respirator can be stretched from a resting height to a stretched height, and recover to the resting height, and the stretched height is at least 10% longer than the resting height.

[0177] The respirator may be implemented such that the center panel includes the layer of wrinkled media.

[0178] The respirator may be implemented such that two of the top panel, bottom panel and center panel include the layer of wrinkled media.

[0179] The respirator may be implemented such that one of the top panel, bottom panel and center panel include unwrinkled nonwoven media.

[0180] The respirator may be implemented such that one of the top panel, bottom panel and center panel include wrinkled and unwrinkled nonwoven media.

[0181] The respirator may be implemented such that a stretched racetrack perimeter of the respirator is 10% longer than a resting racetrack perimeter.

[0182] The respirator may include a stiffening layer.

[0183] The respirator may be implemented such that one of the first and second nonwoven layers includes a membrane.

[0184] The respirator may be implemented such that the seal is a weld, point-weld, bond, point- bond, or seam.

[0185] The respirator may include: a nose clip, a foam layer, a valve, or a harness.

[0186] The respirator may include a strap, and the strap, in combination with one of the top, bottom or center panel, forms a unitary wrinkled media article.

[0187] The respirator may be implemented such that the respirator is configured to remove organic vapors, acid gases, base gases, ozone, or formaldehyde.

[0188] The respirator may be implemented such that the sorbent material is primarily a micro or meso porous adsorbent.

[0189] The respirator may be implemented such that the sorbent material includes activated carbon.

[0190] The respirator may be implemented such the sorbent material is a treated activated carbon.

[0191] The respirator may be implemented such that the sorbent material is a microporous polymer.

[0192] The respirator may be implemented such that the layer of wrinkled media has a longer n-hexane service-life than a sheet of flat media having the same composition and containing the same sorbent material when tested at a 20 liters per minute flow rate, with a 60 ppm n-hexane challenge concentration, 50% relative humidity, and 5 ppm breakthrough.

[0193] The respirator may be implemented such the n-hexane service life is more than 20% longer than the sheet of flat media containing the same sorbent material.

[0194] The respirator may be implemented such the n-hexane service life is more than 50% longer than the sheet of flat media containing the same sorbent material.

[0195] The respirator may be implemented such the service life is more than 20% longer after being stretched and recovered 50 times.

[0196] The respirator may be implemented such the service life is more than 50% longer after being stretched and recovered 50 times.

[0197] The respirator may be implemented such the first non-porous web includes polypropylene.

[0198] The respirator may be implemented such the activated carbon particles are on a surface of the first nonwoven porous web.

[0199] The respirator may be implemented such that the sorbent material includes silica gel, activated alumina, crystalline aluminosilicates, or zeolites.

[0200] The respirator may be implemented such that the sorbent material includes molecular sieve adsorbents or metalorganic frameworks.

[0201] The respirator may be implemented such that the sorbent material includes a functionalized polymeric sorbent.

[0202] The respirator may be implemented such the activated carbon is derived from coal or coconut shells.

[0203] The respirator may be implemented such the activated carbon is deposited as a powder, a granule or a shaped product.

[0204] A cup-shape respirator includes a layer of wrinkled media, the wrinkled media includes: a first series of substantially parallel non-bonded elastic filaments between a first nonwoven porous web and a second nonwoven porous web, the first non-woven porous web includes a sorbent material, the sorbent material includes sorbent particles having a mesh size between about 8x16 and 80x325. The first non-woven porous fibrous web is directly bonded to the second non-woven porous web. At least one portion of the wrinkled media is resiliently extensible under tension.

[0205] The respirator may be implemented such that the respirator further includes: a formed portion that, in a first state, includes curvature in multiple directions.

[0206] The respirator may be implemented such that the respirator can be stretched from a resting height to a stretched height, and recover to the resting height, and the stretched height is at least 10% longer than the resting height.

[0207] The respirator may include a shell layer.

[0208] The respirator may be implemented such the shell layer is an outer layer.

[0209] The respirator may be implemented such the shell layer is an inner layer.

[0210] The respirator may be implemented such that the respirator is resilient such that the curvature recovers after a force is applied to the curvature.

[0211] The respirator may be implemented such that a stretched racetrack perimeter of the respirator is 10% longer than a resting racetrack perimeter.

[0212] The respirator may be implemented such that one of the first and second nonwoven porous webs includes a membrane.

[0213] The respirator may include a cover web layer.

[0214] The respirator may include: a nose clip, a foam layer, a valve, or a harness.

[0215] The respirator may include a strap, and the strap, in combination with the layer of wrinkled media, forms a unitary wrinkled media article.

[0216] The respirator may be implemented such that the respirator is configured to remove organic vapors, acid gases, base gases, ozone, or formaldehyde.

[0217] The respirator may be implemented such that the sorbent material is primarily a micro or meso porous adsorbent.

[0218] The respirator may be implemented such that the sorbent material includes activated carbon.

[0219] The respirator may be implemented such the sorbent material is a treated activated carbon.

[0220] The respirator may be implemented such that the sorbent material is a microporous polymer.

[0221] The respirator may be implemented such that the wrinkled media has a longer n-hexane service-life than a sheet of flat media having the same composition and containing the same sorbent material when tested at a 20 liters per minute flow rate, with a 60 ppm n-hexane challenge concentration, 50% relative humidity, and 5 ppm breakthrough.

[0222] The respirator may be implemented such the n-hexane service life is more than 20% longer than the sheet of flat media containing the same sorbent material.

[0223] The respirator may be implemented such the n-hexane service life is more than 50% longer than the sheet of flat media containing the same sorbent material.

[0224] The respirator may be implemented such the service life is more than 20% longer after being stretched and recovered 50 times.

[0225] The respirator may be implemented such the service life is more than 50% longer after being stretched and recovered 50 times.

[0226] The respirator may be implemented such the first non-porous web includes polypropylene.

[0227] The respirator may be implemented such the activated carbon particles are substantially all on a surface of the first nonwoven porous web.

[0228] The respirator may be implemented such that the sorbent material includes silica gel, activated alumina, crystalline aluminosilicates, or zeolites.

[0229] The respirator may be implemented such that the sorbent material includes molecular sieve adsorbents or metalorganic frameworks.

[0230] The respirator may be implemented such that the sorbent material includes a functionalized polymeric sorbent.

[0231] The respirator may be implemented such the activated carbon is derived from coal or coconut shells.

[0232] The respirator may be implemented such the activated carbon is deposited as a powder, a granule or a shaped product.

[0233] A vertical fold respirator includes a layer of wrinkled media. The wrinkled media includes: a first series of substantially parallel non-bonded elastic filaments a first nonwoven porous web and a second nonwoven porous web, the first non-woven porous web includes a sorbent material, the sorbent material includes sorbent particles having a mesh size between about 8x16 and 80x325, the first non-woven porous fibrous web is directly bonded to the second non-woven porous fibrous web. At least one portion of the wrinkled media is resiliently extensible under tension.

[0234] The respirator may be implemented such that the respirator is configured to fold flat along a centerline.

[0235] The respirator may be implemented such that the respirator can be stretched from a resting length to a stretched length, and recover to the resting length, and the stretched length is 10% longer than the resting length.

[0236] The respirator may include a shell layer.

[0237] The respirator may be implemented such that a stretched racetrack perimeter of the respirator is 10% longer than a resting racetrack perimeter.

[0238] The respirator may include a cover web layer.

[0239] The respirator may include: a nose clip, a foam layer, a valve, or a harness.

[0240] The respirator may include a strap, and the strap, in combination with the layer of wrinkled media, forms a unitary wrinkled media article.

[0241] The respirator may be implemented such that one of the first and second nonwoven layers includes a membrane.

[0242] The respirator may be implemented such that one of the first and second nonwoven layers includes a fibrous nonwoven material.

[0243] The respirator may be implemented such that the respirator is configured to remove organic vapors, acid gases, base gases, ozone, or formaldehyde.

[0244] The respirator may be implemented such that the sorbent material is primarily a micro or meso porous adsorbent.

[0245] The respirator may be implemented such that the sorbent material includes activated carbon.

[0246] The respirator may be implemented such the sorbent material is a treated activated carbon.

[0247] The respirator may be implemented such that the sorbent material is a microporous polymer.

[0248] The respirator may be implemented such that the wrinkled media has a longer n-hexane service-life than a sheet of flat media having the same composition and containing the same sorbent material when tested at a 20 liters per minute flow rate, with a 60 ppm n-hexane challenge concentration, 50% relative humidity, and 5 ppm breakthrough.

[0249] The respirator may be implemented such the n-hexane service life is more than 20% longer than the sheet of flat media containing the same sorbent material.

[0250] The respirator may be implemented such the n-hexane service life is more than 50% longer than the sheet of flat media containing the same sorbent material.

[0251] The respirator may be implemented such the service life is more than 20% longer after being stretched and recovered 50 times.

[0252] The respirator may be implemented such the service life is more than 50% longer after being stretched and recovered 50 times.

[0253] The respirator may be implemented such the first non-porous web includes polypropylene.

[0254] The respirator may be implemented such the activated carbon particles are on a surface of the first nonwoven porous web.

[0255] The respirator may be implemented such that the sorbent material includes silica gel, activated alumina, crystalline aluminosilicates, or zeolites.

[0256] The respirator may be implemented such that the sorbent material includes molecular sieve adsorbents or metalorganic frameworks.

[0257] The respirator may be implemented such that the sorbent material includes a functionalized polymeric sorbent.

[0258] The respirator may be implemented such the activated carbon is derived from coal or coconut shells.

[0259] The respirator may be implemented such the activated carbon is deposited as a powder, a granule or a shaped product.

[0260] A duckbill respirator includes a layer of wrinkled media. The wrinkled media includes: a first series of substantially parallel non-bonded elastic filaments between a first nonwoven porous web and a second nonwoven porous web, the first non-woven porous web includes a sorbent material, the sorbent material includes sorbent particles having a mesh size between about 8x16 and 80x325. The first non-woven porous fibrous web is directly bonded to the second non-woven porous fibrous web. At least one portion of the wrinkled media is resiliently extensible under tension.

[0261] The respirator may be implemented such that the respirator further includes: the respirator is configured to fold flat along a centerline.

[0262] The respirator may be implemented such that and further includes: a first generally trapezoidal portion configured to contact a nose of a wearer, a second generally trapezoidal portion configured to contact a chin of a wearer. One of the first and second generally trapezoidal portions includes the layer of wrinkled media.

[0263] The respirator may be implemented such that the respirator can be stretched from a resting length to a stretched length, and recover to the resting length, and the stretched length is 10% longer than the resting length.

[0264] The respirator may include a shell layer.

[0265] The respirator may include an elastic net.

[0266] The respirator may be implemented such that a stretched racetrack perimeter of the respirator is 10% longer than a resting racetrack perimeter.

[0267] The respirator may include a cover web layer.

[0268] The respirator may include: a nose clip, a foam layer, a valve, or a harness.

[0269] The respirator may include a strap, and the strap, in combination with the layer of wrinkled media, forms a unitary wrinkled media article.

[0270] The respirator may be implemented such that the respirator is configured to remove organic vapors, acid gases, base gases, ozone, or formaldehyde.

[0271] The respirator may be implemented such that the sorbent material is primarily a micro or meso porous adsorbent.

[0272] The respirator may be implemented such that the sorbent material includes activated carbon.

[0273] The respirator may be implemented such the sorbent material is a treated activated carbon.

[0274] The respirator may be implemented such that the sorbent material is a microporous polymer.

[0275] The respirator may be implemented such that the wrinkled media has a longer n-hexane service-life than a sheet of flat media having the same composition and containing the same sorbent material when tested at a 20 liters per minute flow rate, with a 60 ppm n-hexane challenge concentration, 50% relative humidity, and 5 ppm breakthrough.

[0276] The respirator may be implemented such the n-hexane service life is more than 20% longer than the sheet of flat media containing the same sorbent material.

[0277] The respirator may be implemented such the n-hexane service life is more than 50% longer than the sheet of flat media containing the same sorbent material.

[0278] The respirator may be implemented such the service life is more than 20% longer after being stretched and recovered 50 times.

[0279] The respirator may be implemented such the service life is more than 50% longer after being stretched and recovered 50 times.

[0280] The respirator may be implemented such the first non-porous web includes polypropylene.

[0281] The respirator may be implemented such the activated carbon particles are on a surface of the first nonwoven porous web.

[0282] The respirator may be implemented such that the sorbent material includes silica gel, activated alumina, crystalline aluminosilicates, or zeolites.

[0283] The respirator may be implemented such that the sorbent material includes molecular sieve adsorbents or metalorganic frameworks.

[0284] The respirator may be implemented such that the sorbent material includes a functionalized polymeric sorbent.

[0285] The respirator may be implemented such the activated carbon is derived from coal or coconut shells.

[0286] The respirator may be implemented such the activated carbon is deposited as a powder, a granule or a shaped product.

[0287] A pleated respirator includes: a layer of wrinkled media. The wrinkled media includes: a first series of substantially parallel non-bonded elastic filaments between a first nonwoven porous web and a second nonwoven porous web, the first non-woven porous web includes a sorbent material, the sorbent material includes sorbent particles having a mesh size between about 4x8 and 300x625. The first non-woven porous fibrous web is directly bonded to the second non-woven porous fibrous web. At least one portion of the wrinkled media is resiliently extensible under tension.

[0288] The respirator may be implemented such that the respirator further includes a mask body that has a transversely-extending line of demarcation, a longitudinal axis, first and second weld patterns disposed above and not traversing the line of demarcation on each side of the longitudinal axis, respectively, and third and fourth weld patterns disposed below and not crossing the line of demarcation on each side of the longitudinal axis, respectively, wherein each of the first, second, third, and fourth weld patterns is a two-dimensional enclosed pattern.

[0289] The respirator may be implemented such that the respirator is configured to fold flat along a centerline.

[0290] The respirator may be implemented such that the respirator can be stretched from a resting length to a stretched length, and recover to the resting length, and the stretched length is 10% longer than the resting length.

[0291] The respirator may include a shell layer.

[0292] The respirator may be implemented such that a stretched racetrack perimeter of the respirator is 10% longer than a resting racetrack perimeter.

[0293] The respirator may include a cover web layer.

[0294] The respirator may include: a nose clip, a foam layer, a valve, or a harness.

[0295] The respirator may include a strap.

[0296] The respirator may be implemented such that the respirator is configured to remove organic vapors, acid gases, base gases, ozone, or formaldehyde.

[0297] The respirator may be implemented such that the sorbent material is primarily a micro or meso porous adsorbent.

[0298] The respirator may be implemented such that the sorbent material includes activated carbon.

[0299] The respirator may be implemented such that, the sorbent material is a treated activated carbon.

[0300] The respirator may be implemented such that the sorbent material is a microporous polymer.

[0301] The respirator may be implemented such that the wrinkled media has a longer n-hexane service-life than a sheet of flat media having the same composition and containing the same sorbent material when tested at a 20 liters per minute flow rate, with a 60 ppm n-hexane challenge concentration, 50% relative humidity, and 5 ppm breakthrough.

[0302] The respirator may be implemented such the n-hexane service life is more than 20% longer than the sheet of flat media containing the same sorbent material.

[0303] The respirator may be implemented such the n-hexane service life is more than 50% longer than the sheet of flat media containing the same sorbent material.

[0304] The respirator may be implemented such the service life is more than 20% longer after being stretched and recovered 50 times.

[0305] The respirator may be implemented such the service life is more than 50% longer after being stretched and recovered 50 times.

[0306] The respirator may be implemented such the first non-porous web includes polypropylene.

[0307] The respirator may be implemented such the activated carbon particles are on a surface of the first nonwoven porous web.

[0308] The respirator may be implemented such that the sorbent material includes silica gel, activated alumina, crystalline aluminosilicates, or zeolites.

[0309] The respirator may be implemented such that the sorbent material includes molecular sieve adsorbents or metalorganic frameworks.

[0310] The respirator may be implemented such that the sorbent material includes a functionalized polymeric sorbent.

[0311] The respirator may be implemented such the activated carbon is derived from coal or coconut shells.

[0312] The respirator of may be implemented such the activated carbon is deposited as a powder, a granule or a shaped product.

[0313] A method of making a respirator includes obtaining a wrinkled media article, the wrinkled media article includes a sorbent material, the sorbent material includes sorbent particles having a mesh size between about 8x16 and 80x325. The method includes forming a stack of media layers, the wrinkled media article is a wrinkled layer within the stack of media layers and sealing the stack of media layers. When sealed, the stack of media layers have a resting racetrack perimeter length, and can resiliently stretch to a stretched racetrack perimeter, and the stretched racetrack perimeter is 10% greater than the resting racetrack perimeter.

[0314] The method may include: preforming the stack of media layers, wherein preforming forms the stack of media layers into a cup-shape.

[0315] The method may be implemented such that one layer of the stack of media layers includes a shell layer.

[0316] The method may include: adding one of a nose clip, a foam layer, a valve, or a harness to the stack of media layers before or after sealing.

[0317] The method may be implemented such that sealing includes welding, point-welding, bonding, or point-bonding, or forming a seam.

[0318] The method may be implemented such that the stack of layer further includes one of a cover web, an sorbent layer, a filter layer, or a shell layer.

[0319] The method may include charging the wrinkled filter layer.

[0320] The method may be implemented such that the respirator is a horizontal tri-fold respirator.

[0321] The method may be implemented such that the respirator is a vertical fold respirator.

[0322] The method may be implemented such that the respirator is a cup-shape respirator.

[0323] The method may be implemented such that the respirator is a pleated respirator.

[0324] The method may be implemented such that the respirator is a duck-bill respirator.

[0325] The method may be implemented such that the wrinkled media includes: a first series of substantially parallel non-bonded elastic fibers or filament between a first nonwoven porous web and a second nonwoven porous web, and the first non-woven porous web is directly bonded to the second non-woven porous web.

[0326] The method may be implemented such the sorbent material is positioned between the first and second nonwoven porous webs.

[0327] The respirator may be implemented such that the respirator is configured to remove organic vapors, acid gases, base gases, ozone, or formaldehyde.

[0328] The respirator may be implemented such that the sorbent material is primarily a micro or meso porous adsorbent.

[0329] The respirator may be implemented such that the sorbent material includes activated carbon.

[0330] The respirator may be implemented such the sorbent material is a treated activated carbon.

[0331] The respirator may be implemented such that the sorbent material is a microporous polymer.

[0332] The respirator may be implemented such that the wrinkled media has a longer n-hexane service-life than a sheet of flat media having the same composition and containing the same sorbent material when tested at a 20 liters per minute flow rate, with a 60 ppm n-hexane challenge concentration, 50% relative humidity, and 5 ppm breakthrough.

[0333] The respirator may be implemented such the n-hexane service life is more than 20% longer than the sheet of flat media containing the same sorbent material.

[0334] The respirator may be implemented such the n-hexane service life is more than 50% longer than the sheet of flat media containing the same sorbent material.

[0335] The respirator may be implemented such the service life is more than 20% longer after being stretched and recovered 50 times.

[0336] The respirator may be implemented such the service life is more than 50% longer after being stretched and recovered 50 times.

[0337] The respirator may be implemented such the first non-porous web includes polypropylene.

[0338] The respirator may be implemented such the sorbent material includes activated carbon particles.

[0339] The respirator may be implemented such the activated carbon particles are on a surface of the first nonwoven porous web.

[0340] The respirator may be implemented such that the sorbent material includes silica gel, activated alumina, crystalline aluminosilicates, or zeolites.

[0341] The respirator may be implemented such that the sorbent material includes molecular sieve adsorbents or metalorganic frameworks.

[0342] The respirator may be implemented such that the sorbent material includes a functionalized polymeric sorbent.

[0343] The respirator may be implemented such the activated carbon is derived from coal or coconut shells.

[0344] The respirator may be implemented such the activated carbon is deposited as a powder, a granule or a shaped product. Examples

[0345] Flat web F5 and its wrinkled webs were tested for n-hexane service life. (3) replicates were tested for each. FIGS. 5A-1 and 5A-2 show top and cross-sectional view of flat web F5, respectfully. FIG 5B shows the wrinkled F5 web with a meltblown layer wrinkled together on top. FIG 5C shows the wrinkled F6 web with no meltblown layer on top.

[0346] One additional wrinkled F5 web was repeatedly stretched to near flat state and let recovered for more than 50 times before it was tested for n-hexane service life. The n-hexane service life test conditions were 13.1 LPM (liter per minute) flow rate through a web with 102 cm2opening, 60 ppm n-hexane challenge concentration, 50% RH, and 10 ppm breakthrough. Prior to service life tests, all samples were tested for basis weight (BW) and initial pressure drops at 7 cm / s flow rate. Because wrinkled web of F5 had meltblown web F4 adhered to one side, with adhesive and elastic fibers added as well, the listed BW of wrinkled media took those into account and had them estimated and subtracted from the measured BW. So the listed BW of flat webs and wrinkled webs are more representative of the sorbent weights. Table 4-a shows the comparison. Table 4-a. n-hexane service life, BW and pressure drops of flat and wrinkled F5 webs Samples Sample Description Web BW dP at 7 cm / s n-hexane Stretch (gsm) (mmH2O) Service Life Ratio (min) CE #1-1 Flat web F5, #1 None 231 5.6 62 CE #1-2 Flat web F5, #2 None 226 5.6 62 CE #1-3 Flat web F5, #3 None 228 5.4 59 EX #1-1 Wrinkled web of F5, #1 75% 349 -- 122 EX #1-2 Wrinkled web of F5, #2 75% 369 3.3 114 EX #1-3 Wrinkled web of F5, #3 75% 366 3.3 113 EX #1-4 Wrinkled web of F5, 75% 342 3.5 102 #4, Stretched & recovered 50 times

[0347] Compared to flat web F5, the wrinkled F5 webs had about 60% increase in BW, which indicate roughly 60% more adsorptive OV carbon mass. The wrinkled F5 webs however had significant n-hexane service life improvement to about 90% adsorptive capacity increase and approximately 40% pressure drop reduction. The EX #1-4 had more than 80% n-hexane service life improvement after it was stretched and released repeatedly for more than 50 times that showed excellent recovery and durability of wrinkled web.

[0348] FIGS. 6A-6D illustrate wrinkled web F5 at various levels of stretch. In the transition from FIG.6A to 6D, wrinkled web F5 stretches about 75%.

[0349] Flat web F6 and its wrinkled web were tested for n-hexane service life. The wrinkled webs were made with two different stretch ratios. (2) replicates were tested for each. Additional (2) samples made of 2 layers of flat web F6 stacked were also tested. The n-hexane service life test conditions were 20 LPM flow rate through a web with 102 cm2opening, 60 ppm n-hexane challenge concentration, 50% RH, and 5 ppm breakthrough. Prior to service life test, the BW and initial pressure drops at 7 cm / s flow rate were measured for all samples. Because wrinkled web of F6 had meltblown web F1 adhered to both upstream and downstream sides, with adhesive and elastic fibers added as well, the listed BW of wrinkled media took those into account and had them estimated and subtracted from the measured BW. So the listed BW of flat webs and wrinkled webs are more representative of the sorbent weights. Table 4-b shows the comparison. Table 4-b. n-hexane service life, BW and pressure drops of flat and wrinkled F6 webs n-hexane Web Stretch BW dP at 7 cm / s Service Samples Sample Description Ratio (gsm) (mmH2O) Life (min) CE #2-1 Flat web F6, #1 None 121 2.2 21 CE #2-2 Flat web F6, #2 None 130 2.3 20 CE #2-3 Flat web F6, 2-layers, #1 None 269 4.0 55 CE #2-4 Flat web F6, 2-layers, #2 None 281 4.2 53 EX #2-1 Wrinkled web of F6, #1 90% 274 2.3 39 EX #2-2 Wrinkled web of F6, #2 90% 283 2.3 38 EX #2-3 Wrinkled web of F6, #3 130% 291 2.7 46 EX #2-4 Wrinkled web of F6, #4 130% 315 3.6 54

[0350] Comparing wrinkled sorbent web of F6 to flat web F6, there is a significant increase of n-hexane service life. For EX #2-1 and EX #2-2 with 90% stretch ratio, the n-hexane service life nearly doubled that of flat web CE #2-1 and CE #2-2 while the pressure drops stayed at the same level. For EX #2-3 and EX #2-4 with 130% stretch ratio, the n-hexane service life increased to about 2.5 times that of flat web CE #2-1 and CE #2-2 and the pressure drops went up by about 40%. The benefit of additional 40% stretch ratio in wrinkling web F6 was not as much as in the first 90% stretch ratioin this case. CE #2-3 and CE #2-4 had similar basis weight as EX #2-1 and EX #2-2 with 90% stretch ratio but much higher pressure drops.

[0351] Flat web F7 and its wrinkled web were tested for SO2 service life. (2) replicates of each were tested. Additional (2) samples made of 2 layers of flat web F7 stacked were also tested. The SO2service life test conditions were 20 LPM flow rate through a web with 102 cm2opening, 50 ppm SO2 challenge concentration, 50% RH, and 5 ppm breakthrough. Prior to service life tests, the BW and initial pressure drops at 7 cm / s flow rate were measured for all samples. Because wrinkled web of F7 had meltblown web F1 adhered to both upstream and downstream sides, with adhesive and elastic fibers added as well, the listed BW of wrinkled media took those into account and had them estimated and subtracted from the measured BW. So the listed BW of flat webs and wrinkled webs are more representative of the sorbent weights. Table 5-a shows the comparison. Table 5-a. SO2 service life, basis weight and pressure drops of flat and wrinkled F7 webs Samples Sample Description Web Stretch BW dP at 7 cm / s SO2Service Ratio (gsm) (mmH2O) Life (min) CE #3-1 Flat web F7, #1 None 231 1.9 18 CE #3-2 Flat web F7, 2-layers, #1 None 453 3.3 70 CE #3-3 Flat web F7, 2-layers, #2 None 467 3.3 74 EX #3-1 Wrinkled web of F7, #1 75% 357 2.5 90

[0352] Wrinkled webs EX #3-1 demonstrated significant increase of approximately four times the SO2service life when compared to flat web F7 and maintained similar pressure drop. When compared to CE #3-2 and #3-3, Wrinkled webs EX #3-1 has similar SO2 service life but much lower pressure drop.

[0353] Additional SO2tests were carried out under the same test condition except that the webs were mounted in a fixture with 50.3 cm2opening that led to higher face velocity of 13.9 cm / s. Table 5-b shows the test data for comparison.

[0354] Table 5-b. SO2service life, basis weight and pressure drops of flat and wrinkled F7 webs WebBWdP at 13.9SO2Samples Sample Description Stretch cm / s Serv io(gice Ratsm)(mmH2O)Life (min)CE #3-4 Flat web F7, #2 None 223 5.3 3.4 CE #3-5 Flat web F7, #3 None 227 5.2 4.2 Flat web F7, laminated EX #3-2 with meltblown, adhesive and elasticNone -- 5.1 3.6fibers EX #3-3 Wrinkled web of F7, #2 75% 349 5.2 11 EX #3-4 Wrinkled web of F7, #3 75% 377 4.0 14

[0355] EX #3-2 was made using the same open meltblown, adhesive and elastic fibers as those for wrinkled media, except that the elastic fibers were not stretched so that EX #3-2 remained flat. It demonstrated very similar pressure drop and SO2service life as the original flat web F7 that indicated minimal adverse impact from the minimally added adhesive and elastic strands. Wrinkled webs EX #3-3 and #3-4 demonstrated significant increase of approximately three times the SO2service life and similar pressure drop when compared to flat web F7.

[0356] Flat web F8 and its wrinkled web were tested for HCHO service life. (2) replicates of each were tested. Additional one sample CE #4-3 made of 2 layers of flat web F8 stacked was also tested. The HCHO service life test conditions were 32 LPM flow rate through a web with 102 cm2opening, 50 ppm HCHO challenge concentration, 50% RH, and 5 ppm breakthrough. Because wrinkled web of F8 had meltblown web F1 adhered to both upstream and downstream sides, with adhesive and elastic fibers added as well, the listed BW of wrinkled media took those into account and had them estimated and subtracted from the measured BW. So the listed BW of flat webs and wrinkled webs are more representative of the sorbent weights. Table 6 shows the test data and comparison.

[0357] Table 6. HCHO service life and pressure drops of flat and wrinkled F8 webs Web BW dP at 13.9 HCHO Samples Sample Description Stretch (gsm) cm / s Service Life Ratio (mmH2O) (min) CE #4-1 Flat web F8, #1 None 231 3.5 13 CE #4-2 Flat web F8, #2 None 223 3.4 11 CE #4-3 Flat web F8, 2-layers, #1 None 411 5.8 70 EX #4-1 Wrinkled web of F8, #1 100% 610 9.6 70 EX #4-2 Wrinkled web of F8, #2 100% 705 8.2 96

[0358] Comparing wrinkled sorbent webs EX #4-1 and #4-2 to flat web F8, there was a significant formaldehyde service life increase of more than 5 times. The pressure drops of wrinkled sorbent webs however were 2.6 times that of the flat web F8. As flat web F8 had a high sorbent particle loading weight over 85% and is thicker than flat webs F6 and F7, the resulting wrinkled webs EX #4 had more larger wrinkles touching each other. This can be an indication of benefit of high service life from wrinkled media was counter weighed by the penalty of pressure drop increase.

Claims

What is claimed is:

1. A disposable respirator containing a sorbent media comprising: a layer of wrinkled media, wherein the wrinkled media comprises: a first series of substantially parallel non-bonded elastic fibers or filaments between a first nonwoven porous web and a second nonwoven porous web, wherein the first non- woven porous web comprises a sorbent material, wherein the sorbent material comprises sorbent particles having a mesh size between about 8x16 and 80x325; and wherein the first non-woven porous web is directly bonded to the second non-woven porous web; wherein at least one portion of the wrinkled media is resiliently extensible under tension; and wherein the layer of wrinkled media is formed into the disposable respirator.

2. The respirator of claim 1, wherein the disposable respirator is a horizontal flat-fold style respirator.

3. The respirator of claim 1 or 2, wherein the disposable respirator is a cup-shape style respirator, and wherein the cup-shape respirator comprises a shell.

4. The respirator of any of claims 1-3, wherein the disposable respirator is a vertical-fold style respirator.

5. The respirator of any of claims 1-4, wherein the disposable respirator is a pleated style respirator.

6. The respirator of any of claims 1-5, wherein the disposable respirator is a duck bill style respirator.

7. The respirator of any of claims 1-6, and further comprising: a nose clip, a foam layer, a valve, or a harness.

8. The respirator of any of claims 1-7, and also comprising a strap, and wherein the strap, in combination with the layer of wrinkled media, forms a unitary wrinkled media article.

9. The respirator of any of claims 1-8, wherein one of the first and second nonwoven layers comprises a membrane.

10. The respirator of any of claims 1-9, wherein one of the first and second nonwoven layers comprises a fibrous nonwoven material.

11. The respirator of any of claims 1-10, wherein the respirator is configured to remove gas and vapor air contaminants.

12. The respirator of any of claims 1-11, wherein the wrinkled media has a longer n-hexane service- life than a sheet of flat media having the same composition and containing the same sorbent material when tested at a 20 liters per minute flow rate, with a 60ppm n-hexane challenge concentration, 50% relative humidity, and 5 ppm breakthrough.

13. The respirator of claim 12, wherein the n-hexane service life is more than 20% longer than the sheet of flat media containing the same sorbent material.

14. The respirator of any of claims 1-13 wherein the first non-woven porous web comprises polypropylene.

15. The respirator of claim 14, wherein the sheet comprises activated carbon particles are on a surface of the first nonwoven porous web.

16. The respirator of any of claims 1-15, wherein the second nonwoven porous web comprises a second sorbent material.

17. The respirator of claim 16, wherein the second sorbent material has a different composition from the sorbent material.

18. A horizontal flat-fold respirator comprising: a layer of wrinkled media, wherein the wrinkled media comprises: a first series of substantially parallel non-bonded elastic filaments between a first nonwoven porous web and a second nonwoven porous web, wherein the first non-woven porous web comprises a sorbent material, wherein the sorbent material comprises sorbent particles having a mesh size between about 8x16 and 80x325; wherein the first non-woven porous web is directly bonded to the second non-woven porous web; and wherein at least one portion of the wrinkled media is resiliently extensible under tension.

19. A cup-shape respirator comprising: a layer of wrinkled media, wherein the wrinkled media comprises: a first series of substantially parallel non-bonded elastic filaments between a first nonwoven porous web and a second nonwoven porous web, wherein the first non-woven porous web comprises a sorbent material, wherein the sorbent material comprises sorbent particles having a mesh size between about 8x16 and 80x325; and wherein the first non-woven porous fibrous web is directly bonded to the second non- woven porous web; and wherein at least one portion of the wrinkled media is resiliently extensible under tension.

20. A pleated respirator comprising: a layer of wrinkled media, wherein the wrinkled media comprises: a first series of substantially parallel non-bonded elastic filaments between a first nonwoven porous web and a second nonwoven porous web, wherein the first non-woven porous web comprises a sorbent material, wherein the sorbent material comprises sorbent particles having a mesh size between about 8x16 and 80x325; and wherein the first non-woven porous fibrous web is directly bonded to the second non- woven porous fibrous web; and wherein at least one portion of the wrinkled media is resiliently extensible under tension.

21. A method of making a respirator, the method comprising: obtaining a wrinkled media article, wherein the wrinkled media article comprises a sorbent material, wherein the sorbent material comprises sorbent particles having a mesh size between about 8x16 and 80x325; forming a stack of media layers, wherein the wrinkled media article is a wrinkled layer within the stack of media layers; sealing the stack of media layers; and wherein, when sealed, the stack of media layers have a resting racetrack perimeter length, and can resiliently stretch to a stretched racetrack perimeter, and wherein the stretched racetrack perimeter is 10% greater than the resting racetrack perimeter.

22. The method of claim 21, and further comprising: preforming the stack of media layers, wherein preforming forms the stack of media layers into a cup-shape.

23. The method of claim 21 or 22, wherein one layer of the stack of media layers comprises a shell layer.

24. The method of any of claims 21-23, wherein sealing comprises welding, point-welding, bonding, or point-bonding, or forming a seam.

25. The method of any of claims 21-24, wherein the stack of layer further comprises one of a cover web, an sorbent layer, a filter layer, or a shell layer.

26. The method of any of claims 21-25, wherein the respirator is a horizontal tri-fold respirator, a vertical fold respirator, a cup-shape respirator, a pleated respirator, or a duck-bill respirator.

27. The method of any of claims 21-26, wherein the wrinkled media comprises: a first series of substantially parallel non-bonded elastic fibers or filament between a first nonwoven porous web and a second nonwoven porous web; andwherein the first non-woven porous web is directly bonded to the second non-woven porous web.

28. The respirator of claim 27, wherein the first non-porous web comprises polypropylene.

29. A sheet of wrinkled filter media comprising: a first series of substantially parallel non-bonded elastic fibers or filament between a first non-woven porous web and a second non-woven porous web, wherein the first non-woven porous web comprises a sorbent material, wherein the sorbent material comprises sorbent particles having a mesh size between 4x8 and 300x635; and wherein the first non-woven porous web is directly bonded to the second non-woven porous web; and wherein at least one portion of the wrinkly media is resiliently extensible under tension.

30. The sheet of claim 29, wherein the sheet has a longer n-hexane service-life than a sheet of flat media containing the same sorbent material when tested at a 20 liters per minute flow rate, with a 60 ppm n-hexane challenge concentration, 50% relative humidity, and 5 ppm breakthrough.

31. The sheet of claim 30, wherein the n-hexane service life is more than 20% longer than the sheet of flat media containing the same sorbent material.

32. The sheet of claim 30, wherein the service life is more than 20% longer after being stretched and recovered 50 times.

33. The sheet of claim 29, wherein the first non-porous web comprises polypropylene.

34. The sheet of any of claims 29-33, wherein the sheet has at least a 50% adsorptive capacity increase compared to the sheet of flat media.

35. The sheet of any of claims 29-34, wherein the sheet has at least a 40% pressure drop reduction when compared to the sheet of flat media.

36. The sheet of any of claims 29-35 wherein the sheet has a longer formaldehyde service-life than a sheet of flat media containing the same material when tested at a 32 liters per minute flow rate, at a 50 ppm formaldehyde concentration, 50% relative humidity and 5 ppm breakthrough.

37. The sheet of any of claims 29-36, wherein the sorbent material comprises silica gel, activated alumina, crystalline aluminosilicates, or zeolites, a molecular sieve adsorbent, a metalorganic framework, a functionalized polymeric sorbent, or an active carbon.

38. The sheet of claim 37, wherein the sorbent material is deposited as a powder, a granule or a shaped product.

39. The sheet of any of claims 29-38, wherein the second nonwoven porous web comprises a second sorbent material.

40. The sheet of claim 39, wherein the second sorbent material differs from the sorbent material.

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