Respiratory protection devices and methods of manufacturing the same

Abstract

A respirator including a layer of wrinkled media is presented. The layer of wrinkled media has a transparent window sealed to a body of the respirator such that a mouth of a wearer of the respirator is visible through the transparent window, wherein the respirator is a high-efficiency respirator.

Description

RESPIRATORY PROTECTION DEVICES AND METHODS OF MANUFACTURING THE SAME TECHNICAL FIELD

[0001] Respiratory devices designed with wrinkled expandable filter media and transparent window that enable elasticity, visibility, and low pressure drops, which reduce breathing resistance and provide enhanced comfort and fit to the wearer. SUMMARY

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

[0003] A respirator including a layer of wrinkled media is presented. The layer of wrinkled media has a transparent window sealed to a body of the respirator such that a mouth of a wearer of the respirator is visible through the transparent window, wherein the respirator is a high-efficiency 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] FIG. 3 is a schematic representation of making a shirred filter media according to one embodiment of the present disclosure.

[0008] FIGS.4A-4C illustrate a cup-shaped respirator in accordance with embodiments herein.

[0009] FIGS.5A-5F illustrate horizontal flat fold respirators in accordance with embodiments herein.

[0010] FIGS.6A-6C illustrate embodiments of a horizontal flat-fold respirator having a window panel.

[0011] FIGS.7A-7F illustrate respirators having transparent portions in accordance with embodiments herein.

[0012] FIG. 8 illustrates a method of making a respiratory protection device in accordance with embodiments herein.

[0013] 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

[0014] 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).

[0015] 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.).

[0016] 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.).

[0017] 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.

[0018] As used herein, the term “respirator” refers to a close-fitting facial covering device that filters inhaled and 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 fibers that are electrically charged to attract particles, increasing loading capacity.

[0019] 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.

[0020] 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, leaks, or even scratches to wear’s face. 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 and expandable respirator designs able to accommodate a larger range of face sizes.

[0021] Another problem in both the mask and respirator space is that face coverings block a view of a wearer’s mouth, making communication difficult. A respirator that meets safety requirements (e.g. N95, KN94, FFP1, etc.) but also includes a transparent window is desired. The NIOSH standard for N95 compliance is that a respirator filters at least 95% of airborne particles that have a mass median aerodynamic diameter of 0.3 micrometers.

[0022] Manufacturers of both respirators and masks have attempted to add clear panels to face coverings to solve this problem. However, the clear plastic panels reduce the filtration or breathing area of a face covering that allows air exchange. As the area of a breathing zone is reduced, a pressure drop across the face covering increases and filtration efficiency decreases, which increases a breathing resistance and lowers protection. Additionally, as a user exhales, fog will form on a clear film, negating the benefit of a transparent window.

[0023] Additionally, while products have been sold that include a transparent window, the market needs a respirator option with a compact design that meets safety requirements. U.S. Pat.11,123,581 to Sharp Medical Products, for example, states that N95 or N99 filter media material may be used, but does not provide a respirator that, as a whole, passes N95 or N99 testing standards. Optrel Inc. USA sells the “P. Air Clear,” which it states has 20% more breathing resistance than respirators without a transparent window. Many products also use filtration material for only part of a face covering, which contributes to poor filter efficacy and increases the pressure drop.

[0024] Described herein are disposable respirators that provide sufficient filtration functionality, incorporate a transparent window, all while maintaining a low pressure drop. Disposable respirators as described herein are formed using wrinkled media and include a window with antifog coating.

[0025] 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, provide both a larger surface area, which increases breathability, and stretchability, which allows respirator models to fit a broader range of facial shapes and helps maintain a respirator seal while a user moves and speaks.

[0026] 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.

[0027] As used herein, the term “transparent” refers to any material through which a wearer’s mouth movements can be viewed and understood. Transparent windows herein may be fully transparent, e.g. allowing 100% of light transmission therethrough, or may have some translucency, e.g. allowing less than 100% of light transmission therethrough. In some cases, “transparent” means that visible light can pass therethrough sufficiently to enable the desired image on the opposing side of the structure (window). Additionally, in some embodiments, a transparent window includes some portions with a higher transparency than others – for example sections with higher opacity alternating with sections of lower opacity, manifested, e.g., in a geometric (e.g., checkerboard, striped, or dot) pattern. In some embodiments, sections with higher opacity may gradually transition to sections of lower opacity. Atransparent window for a respirator, as used herein, implies that a material is “see-through” such that a user can see through it clearly enough to see the mouth movements of the wearer of the respirator. Transparent windows in accordance with embodiments herein may be clear, may have some translucency, may have some color tinting, etc.

[0028] As used herein, the term “high efficiency respirator” refers to a respirator that meets a regulatory standard for filtration efficiency. For example, respirators herein may be class N95 per NIOSH FFR (Filtering Facepiece Respirator) classification, such that the respirator filters out at least 95% of airborne particles having a mass median aerodynamic diameter of 0.3 micrometers. However, “high efficiency” is not limited to NIOSH classifications such as N95, or R99, or P100 for examples. Respirators in embodiments herein may meet the EN 149 performance requirements. Respirators herein may be FFP1 compliant, for example, filtering at least 80% of airborne particles. Respirators in embodiments herein may be FFP2 compliant, filtering at least 94% of airborne particles. Respirators in embodiments herein may be FFP3 compliant, filtering at least 99% of airborne particles. 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 filaments that are spaced apart. 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 fibers 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. 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 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 filament along the full length of the filament. Material Tables – Nonwoven Media

[0029] Table 1 lists examples of the nonwoven webs used in making shirred media as described in US Provisional Patent Application 63 / 434365, Filed December 21, 2022 and Table 2 lists their initial pressure drop (dP) and penetration of flat nonwoven webs in NaCl tests. Table 3 lists dP and penetration of wrinkled webs in initial NaCl tests.Table 1. Nonwoven webs used in making shirred media and respirators Media ID Media Material Source Properties F1 Polypropylene A non-woven meltblown fibrous web Having a basis weight of 35 having fibers with a charging additive gsm, a thickness of 0.62 mm, package as described in US 10,724,171 6.2% solidity, and an effective (Schultz et al.), which can be prepared fiber diameter of 7.9 per 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 18 having fibers with a charging additive gsm, a thickness of 0.19 mm, package as described in US 10,724,171, 7.7% solidity, and an effective which can be prepared per Process A and fiber diameter of 7.0 Charging Method 3 as disclosed in US micrometers. 10,724,171. F3 Polypropylene A spunbond nonwoven coverweb media Having a basis weight of 35 gsm, a thickness of 0.38 mm, and an effective fiber diameter of approximately 16 micrometers F4 Polypropylene A non-woven scrim with blue printed pattern 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 QF (Quality ID. (mmH2O) Pen Factor) F1 Meltblown 7.9 µm 3.8 2.49% 0.99 F2 Meltblown 7.0 µm 2.0 15.1% 0.93 F3 Spunbond 16 µm 1.7 93.5% 0.03 F4 Scrim -- -- -- Table 3. Wrinkled nonwoven webs’ initial dP and penetration in NaCl tests Wrinkled Nonwoven Media websNaCl test at 13.9 cm / s Media Media Initial dP Initial QF ID. (mmH2O) Pen F5 Wrinkled webs F1 and F3, 5.9 0.16% 1.1 150% stretch ratio F6 Wrinkled webs F1 and F4, 4.8 0.38% 1.2 150% stretch ratio F7 Wrinkled webs F2 and F2, 2.7 0.46% 2.0 150% stretch ratio Elastic filaments

[0030] The elastic filaments 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.

[0031] As used herein, the terms “fiber” refers to multiple “filaments” coupled together. It is noted that while one term may be used with respect to a particular embodiment, that embodiments herein may use either a single elastic filament or a plurality of elastic filaments coupled together to form an elastic fiber.

[0032] One example of an elastic fiber roll is available under the trade designation “100% Lycra Spandex 235 Multifil”, DTEX Type 737, 210 denier from Invista Company, Wichita, Kansas. Another elastic filament example is made of a propylene and ethylene co-polymer with a density of 0.85-0.9 g / cc. Exemplary types of polymeric materials that may be used for filaments 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.

[0033] In one embodiment, the filaments and / or fibers 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 filaments have a denier of at least 100, 150, 175, 200, 210, 220, 250, or even 500. In one embodiment, the filaments 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

[0034] The plurality of elastic 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).

[0035] 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 rapidlyreduced. 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.

[0036] 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).

[0037] 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).

[0038] 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).

[0039] Suitable poly(ether sulfones) include, but are not limited to, poly(diphenylether sulfone) and poly(diphenylsulfone-co-diphenylene oxide sulfone).

[0040] 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).

[0041] The fibers selected for the non-woven web depend upon the kind of particulate to be filtered. Particularly useful fibers include webs of melt-blown 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 melt-blown 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 ofglass fibers are also useful, as are solution spun, or electrostatically sprayed fibers, especially in microfiber form.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] Particularly preferred change enhancing additives include hindered amine-based additives, triazine-based additives, and hindered phenol-based additives.

[0046] 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").

[0047] 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.

[0048] 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.

[0049] 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.).

[0050] 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 amountranging 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

[0051] 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, a PVDF nanofiber membrane, a cellulose ester nanofiber membrane, a polyvinyl acetate or alcohol nanofiber membrane, a nylon membrane, or a polyvinyl butyral nanofiber membrane.

[0052] 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).

[0053] A wrinkled 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 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 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

[0054] Non-woven porous web may include a sorbent material. 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 or flexible 3D framework. One example of the sorbent material is activated carbon.

[0055] 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 insome 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.

[0056] 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.

[0057] 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 melt blown 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. 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 filaments of the present disclosure are not a scrim). The plurality of elastic filaments in the first series are held (for example using a spacer) such that each of the filaments is substantially parallel to one another and are spaced a given distance apart. Generally, the substantially parallel filaments should not touch the nearest neighbor 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 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 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 filaments 32, wherein the filaments are tied at either end and combs 35 and 37 are used at both ends to hold the filamentssubstantially parallel. The first series of filaments are placed between first non-woven porous fibrous web 34 and second non-woven porous fibrous web 36. Nonwoven web 36 is placed below the stretched plurality of parallel filaments with the adhesive side contacting the filaments. The second adhesive- sprayed web 34 is placed above the stretched plurality of parallel filaments with the adhesive side contacting the filaments. Then, a cardboard roller compresses the laminate gently to remove any air pockets so that the two nonwoven webs were adhered together with the filaments positioned in between the two webs.

[0060] The manual hold of the stretched plurality of parallel filaments is then released, and the filaments are allowed to relax causing the laminated media (web-adhesive-filament-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.

[0061] The filaments can be stretched to any desired length. The % stretch as used herein is defined as the difference between the length of the stretched filament and the length of the initial relaxed filament divided by the length of the initial relaxed filament converted to a percent. In one embodiment, the elastic fibers or filaments are stretched to greater than 50, 75, 100, 150, 200, or even 250%. The 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.

[0062] 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.

[0063] 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 Bostikinc., 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 the adhesive can maintain cohesiveness (or keep the two layers of non-woven webs bonded) upon the relaxing of the stretched 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.

[0064] 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.

[0065] 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 layer may be added before release of the tension on the 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 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.

[0066] In another embodiment, in addition to the first series of elastic filaments, a second series of fibers or filaments can also be used, wherein the first and second series of elastic 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 filaments are placed between the two non-woven webs. When tension is released on both series of filaments, the resulting article has a more complex puckered pattern as shown in the Example Section.

[0067] In yet another embodiment, the series of elastic filaments may be stretched to different percentages, such that when the tension is released the resulting puckered material comprises areas with more puckering and areas with less puckering.

[0068] 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 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.

[0069] 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 10, 15, 20, 30, 40, 50, 75, or even 100 grams per square meter (gsm). In one embodiment, the shirred articles of the present disclosure have a basis weight of at most 100, 125, 150, 175, 180, 200, 225, 250, or even 300 gsm.

[0070] The resulting shirred media is self-supporting meaning that an addition layer is not needed to provide support to the non-woven web / 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.

[0071] The filter media of the present disclosure described herein may have a variety of suitable air permeabilities. In one embodiment, the filter media has an air permeability of greater than or equal to 2, 5, 10, 15, 20, 25, 30, 40, 50, 75, 100, 120, 150, 170, 200, 275, 300, 350, 400 or even 450 CFM / sqft. In some embodiments, the filter media has an air permeability of less than or equal to 450, 400, 350, 325, 300, 275, 250, 225, 200, 170, 150, 120, 100, 75, 60, 50, 40, 35, 30, or even 25 CFM / sqft. Combinations of the above-referenced ranges are also possible (e.g., greater than or equal to 20 CFM / sqft and less than or equal to 350 CFM / sqft, greater than or equal to 35 CFM / sqft and less than or equal to 170 CFM / sqft, or greater than or equal to 20 CFM / sqft and less than or equal to 350 CFM / sqft). Other ranges are also possible. The air permeability of a filter media may be determined in accordance with ASTM Test Standard D737 (1996).

[0072] Filtration performance test results of shirred media articles are discussed in greater detail in US Provisional Patent Application 63 / 434365, filed December 21, specifically in the Examples Section, which is incorporated herein by reference.Test Methods

[0073] 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.

[0074] Unless otherwise noted, all initial and loading NaCl penetration and pressure drop tests for webs were run at a face velocity of 13.9 cm / sec. The listed media web performance in Tables 3 are actual measurements per Test Methods listed.

[0075] The respirator samples were mounted on holders designed for specific respirator types within corresponding test chambers for testing. For example, the horizontal flat fold respirator like Aura respirator had the headbands and staples removed first, when applicable. Then the flat folds were opened up to be set on an open cylindrical holder with respirator outlet or downstream side facing up. The two sides where headbands were stapled or welded to were spread out and positioned into two grooves on the cylindrical holder. Optionally, the holder may have a dome-shaped open structure in the opening area to provide support to the respirator. With the respirator fully open and set on the holder, a slightly larger cylindrical ring was pushed onto the perimeter of the mounted respirator, so the respirator perimeter was sandwiched between the holder and ring to form a tight seal. The mounted assembly was then placed in a test chamber, which may provide further compression during the tests to ensure a good seal.

[0076] In another example, the cup shaped respirator can be mounted in a holder in a similar fashion but with holder dimensions designed for the specific cup style. The holder with respirator mounted on was then positioned and aligned on a tester such as the TSITMModel 8130 high-speed automated filter tester (available from TSI Inc., Shoreview, Minnesota) for testing. Optionally, a larger size cup shaped respirator or a cup shaped respirator samples with perimeter extended out and with adequate mechanical resistance from deformation or collapse under air flow, may also be directly placed on top of the lower chuck of a TSITMModel 8130 high-speed automated filter tester (available from TSI Inc., Shoreview, Minnesota) with its outlet or downstream side facing up. When the upper chuck came down upon testing command, the respirator perimeter was compressed and sealed under the pressure between upper and lower chucks.

[0077] Other styles of respirators such as 3M™ VFlex™ respirator or vertical flat fold respirator available under the trade designation “3M Disposable Respirator 9105 or 9010” from 3M Company, Maplewood, MN, USA may be mounted on holders specifically designed for their shapes and sizes and tested in a similar fashion.The respirator holders and test chambers can be made of various materials. Some were selected due to their transparency property for easy observation of test. The examples include plexiglass, polycarbonate, acrylic and polystyrene. NaCl Initial Tests and Quality Factor:

[0078] 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.

[0079] 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.

[0080] The NaCl particles are forced through a respirator or a media sample that has 11.4 cm in diameter or 102 cm2opening at a rate of 85 LPM.

[0081] The NaCl percent penetration is defined by the following formula: %Pen = (Concentration downstream / Concentration upstream) x100 Equation 1

[0082] 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

[0083] A higher initial QF value indicates better initial filtration performance. Decreased QF values effectively correlate with decreased filtration performance. NaCl Loading Test:

[0084] Loading tests were performed on a TSI™ Model 8130 high-speed automated filter tester (available from TSI Inc., Shoreview, Minnesota) according to the procedure set forth in the tester manual. The samples received continuous NaCl challenge at 85 LPM with the particle ionizer operating. Tested flat samples were a respirator or flat web that had an exposed area of 100.2 cm2with a nominal face velocity of 13.9 cm / sec for flat and wrinkled media sheets.

[0085] The samples may be loaded with NaCl particles till a pre-determined amount of NaCl particles was reached or till the pressure drop reached a pre-determined threshold. The calibrated photometers may be employed at the filter inlet and outlet to measure the particle concentration and the % particle penetration through the filter. Loading Quality Factor:

[0086] The loading quality factor (LQF) at a given face velocity for each respirator example in NaCl loading test was calculated to compare for their capability in capturing particles per pressure drop increase. It is defined by Equation 1: ^^^^^^ ൌ ்^௧^^ ^^^ௗ^ௗ ^^^௧^^^^ ^^^^ ^^ି%^^^ / ^^^^^^^^^௨^^ ^^^^ ^^^௧^ Equation 1

[0087] The Pressure Drop Delta is the pressure drop increase at the end of loading determined by either the total loading time or the total loading weight. LQF has the unit of [mg / mmH2O / respirator]. Each respirator sample is considered a complete unit regardless of features such as number of panels or transparent window added or not. At a given flow face velocity, a higher LQF indicates higher capture of aerosol particles by the respirator sample at the same pressure drop increase. Details for calculating these values are presented in following data table.

[0088] 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. These, and other examples, are discussed in greater depth in US Provisional Patent Application Ser. Nos.63 / 496,002 and 63 / 496,003, both filed April 13, 2023.

[0089] 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.

[0090] 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).

[0091] FIGS.4A-4C illustrate disposable respirators formed from wrinkled media in accordance with embodiments herein. FIGS. 4A-4C illustrate cup-shaped respirators, however it is expressly contemplated that other respirator models are envisioned in accordance with embodiments herein.

[0092] FIG. 4A illustrates a respirator 410 formed of wrinkled media with no transparent window. FIGS. 4B-4C illustrate a respirator 420 with a transparent window. In some embodiments, a hole is cut from a respirator body and the transparent window is sealed such that it covers the hole withminimal leakage. For example, the transparent window may be sealed using adhesive placed around a perimeter of the transparent window. However, it is expressly contemplated that a transparent window may be welded or stitched into place in accordance with embodiments herein. FIG. 4C illustrates a transparency of Example respirator 420, where the word “MAY” is legible through the window. While “transparent” is used herein to describe a window in a respirator, it is expressly contemplated that the window may be translucent or shaded, and not clear.

[0093] There is a trade-off between the area of the transparent window and filtration performance of the respirator. As the area of the window increases, the filtration area for breathing decreases. Forming a respirator body with wrinkled media provides a significantly larger filter surface area, allowing for a larger transparent window with a smaller pressure drop and penetration rise than a respirator body formed with flat media such as 3M 8210Plus respirator (available from 3m.com), as illustrated in Table 3, below.

[0094] While one size of a transparent window 422 is illustrated in FIGS. 4B-4C, it is expressly contemplated that respirators in accordance with embodiments herein may have a transparent window that replaces at least 10% of a surface area of a respirator body. In some embodiments, a transparent window replaces at least 20% of a surface area of a respirator body, or at least 30% of the surface area, or at least 40% of the surface area, or at least 50% of the surface area. In some embodiments, a transparent window replaces less than 99% of a surface area of a respirator, or less than 90% of the surface area, or less than 80% of the surface area, or less than 70% of the surface area, or less than 60% of the surface area, or less than 50% of the surface area, or less than 40% of the surface area, or less than 30% of the surface area.

[0095] Respirators 410 and 420 were both formed of web F7. Table 4. Comparison of cup-shaped respirators with flat media and cup-shaped respirators with wrinkled media and a window NaCl Tests at 85 LPM Sample Configuration Initial dP Initial QF (mm H2O) % Pen 8210Plus Control Flat media, no window 8.1 0.468 0.66 8210 Example (410) Wrinkled media, no window 3.6 0.108 1.9 8210 Example (420) Wrinkled media, with 4.1 0.432 1.33 window

[0096] When compared to a respirator formed of flat media (e.g.8210Plus control), a respirator made from wrinkled media (e.g. example respirator 420) can incorporate a window while still having a low pressure drop. In contrast, if the 8210Plus Control respirator has a similarly sized window, it mayhave a pressure drop as high as 11 mmH2O or even higher depending on the window size. The QFs of respirators 410 and 420 are significantly higher than 8210Plus Control.

[0097] FIGS. 5A-5F illustrate horizontal trifold style respirators in accordance with embodiments herein. FIGS.5A-5B illustrate a horizontal trifold respirator 510, made from flat filter material, with a transparent window 512 inserted into a front panel.

[0098] FIGS. 5C-5F illustrate a horizontal trifold respirator formed of wrinkled media F6 as listed in Table 3. FIG.5C and 5D illustrate views of a center panel 520 of a trifold respirator formed of wrinkled media, with a window section 522 to be removed along a window perimeter 524. A window perimeter 524 may be formed through die-cutting, welding, laser-cutting or using another suitable mechanism.

[0099] FIGS. 5E-5F illustrate a horizontal tri-fold respirator 530 with an aperture 532 to receive a window. A window may be sealed into place along perimeter 534, for example using stitching, bonding, point-bonding, welding, or another suitable sealing mechanism.

[0100] FIGS. 6A-6C illustrate two embodiments of horizontal flat-fold respirators having window panels. FIG. 6A illustrates a front view of a full window covering entire center panel. The panel has panel length 100 and a panel height 110. The respirator of FIG.6A has flat media in top and bottom panels and allows almost all-around view of wearer’s mouth.

[0101] FIGS. 6B-6C illustrate a front and side view, respectively, of a respirator having a smaller transparent window portion. Window 120 is a partial window covering about 67% of center panel area. The respirator has wrinkled media forming the top and bottom panels 130, and flat media forming the center panel 140. The winkled media in top and bottom panels were oriented to be stretchy in the direction from ear to ear in this embodiment. They can be oriented in other direction. Each of the top, center and bottom panels can have either wrinkled or flat media. A partial window design may obscure part of a wearer’s mouth in a side view.

[0102] It is noted that the size of a transparent portion impacts the respirator performance as the transparent portion material inhibits air exchange. The smaller the window is, the less impact it has on an experienced pressure drop, filtration efficiency or QF of a respirator. However, because the transparent portion is designed to allow a viewer to see the mouth movements of a wearer, it must be sized so that mouth movements are viewable and speech understood. Both size and design of window can impact visibility o mouth movements. It is expressly contemplated that embodiments herein may utilize different shapes and sizes in order to reduce a window area while increasing visibility. For example, replacing an entire front panel of a respirator provides significant visibility, but will lead to a larger pressure drop, lower filtration efficiency and will be less comfortable. In contrast, an oval- shaped window as an example that replaces only 40% of a first panel may allow for enough visibility without the sacrificed comfort and filtration efficiency.

[0103] Table 5 summarizes the construction of a number of respirator models described herein. All flat media used in these respirator examples, except for CE 3, are the same as those used in 3M Aura™ respirator 8210. All wrinkled media used in these examples are web F5. Table 5. List of respirator examples and configurations Example Style Top Panel Center Panel Bottom PanelCE 1 3M Aura™ horizonal tri-fold Flat media No window, Flat media Flat media EX 1 Horizonal tri-fold Flat media Partial window, Flat media Flat media CE 2 Horizontal tri-fold Flat media No window, Flat media Flat media EX 2 Horizontal tri-fold Flat media Full window Flat media EX 3 Horizontal tri-fold Flat media Partial window, Flat media Flat media CE 3 Optrel™ P. Air Clear Flat media Partial window, Flat media Flat media EX 4 Horizontal tri-fold Flat media Partial window, Flat media Wrinkled media EX 6 Horizontal tri-fold Wrinkled media Partial window, Flat media Wrinkled media EX 7 Horizontal tri-fold Flat media Partial window, Wrinkled media Wrinkled media EX 10 Horizontal tri-fold Wrinkled Partial window, Wrinkled media media Wrinkled media EX 11 Horizontal tri-fold Wrinkled Partial window, Wrinkled media media 2 layers Wrinkled media

[0104] CE1 is 3M standard Aura respirator (available from 3M, St Paul, MN, USA). EX 1 is an Aura style respirator with a transparent window added to center panel and replacing a portion of filtration media in center panel. All media used were flat.

[0105] CE 2 is a horizonal tri-fold respirator with all flat media. EX 2 has the same construction as CE 2 except that the entire center panel media was replaced with a transparent window. EX 3 has the same construction as CE 2 except that part of the center panel media was replaced with a transparent window. All media used were flat.

[0106] CE 3 is an Optrel™ P. Air Clear N95 mask (Lot 2302-106, Model 4190.020, obtained from Optrel Inc.).

[0107] EX 4, 6, 7 and 10 have the same construction as EX 3, except that one or more panels or a portion of center panel used wrinkled media.

[0108] Table 6 lists the maximum width and height of window, % area of window over center panel, filtration pressure drop and penetration of each of above respirators in initial NaCl tests at 85 LPM.Table 6 lists window sizes, % area, initial filtration dP and penetration of each respirator Est. % of Window Window Window Area NaCl Initial Test at 85 LPM Max Max over Center Width Height Panel Area dP %Pen QF (cm) (cm) (mmH2O) (%)CE 1 NA NA 0% 7.6 0.09 0.93 EX 1 9.0 6.5 54% 11.9 0.39 0.47 CE 2 NA NA 0% 7.2 0.08 0.99 EX 2 17.5 7.5 100% 13.3 0.44 0.41 EX 3 7.5 7.2 67% 9.9 0.71 0.50 CE 3 9.5 7.2 61% 26.8 1.00 0.17 EX 4 7.5 7.2 67% 9.5 0.51 0.56 EX 6 7.5 7.2 67% 7.4 0.58 0.70 EX 7 7.5 7.2 67% 7.4 0.71 0.67 EX 10 7.8 7.2 69% 5.5 0.76 0.89 EX 11 7.8 7.2 69% 6.2 0.61 0.82

[0109] Compared to CE 1, EX 1 showed clearly the addition of a transparent window that reduced the respirator filtration area led to significant pressure drop rise of more than 55% and also penetration increase. Compared to CE 2, EX 2 showed even higher pressure drop rise of over 80% and penetration increase. However, compared to EX 2 that had full window in center panel, EX 3 with partial window had lower pressure drop rise of about 35% over CE 2.

[0110] Compared to EX 3 that had all flat media, EX 4 had wrinkled media in bottom panel. Its initial pressure drop was lower than EX 3’s due to the extra filtration surface area from wrinkled media.

[0111] EX 6 and 7 incorporated wrinkled media in two panels, which provided more surface area for air flowing through. Their initial pressure drops were even lower than that of EX 4.

[0112] EX 10 used wrinkled media in all three panels. Even with its transparent window replacing 69% of center panel media, the extra surface area from wrinkled media enabled 25% lower pressure drop than CE 1.

[0113] EX 11 used wrinkled media in all three panels, with 2-layers of wrinkled media in center panel. Even with the window, EX 11 experienced a pressure drop of 6.2 mmH2O, lower than both window-less CE 1 and CE 2. EX 11 had an initial QF of 0.82, slightly lower than the QF of CE 1 and CE 2.

[0114] When the entire center panel of CE 2 respirator was replaced with a window to make EX 2, an initial pressure drop increased by 85% from 7.2 to 13.3 mmH2O and the QF dropped more than 50% from 0.99 to 0.41. When a portion or about 67% of center panel of CE 2 was replaced witha window to make EX 3, the initial pressure drop increase was about 38% from 7.2 to 9.9 mmH2O and QF drop was about 50% from 0.93 to 0.47. When a portion or about 54% of center panel of CE 1 respirator was replaced with a window to make EX 1, its initial pressure drop was significantly increased by 58% and the QF dropped 50%.

[0115] When wrinkled media was incorporated in one or multiple panels of examples EX 4 through EX 11, with a window taking 67% area of center panel for all, the initial pressure drops were all lower than 10 mmH2O and initial QF were higher than 0.55.

[0116] The respirators were also tested for NaCl loading performance. Table 7 lists the initial and final pressure drops upon 30 mg NaCl loading, the pressure drop rise, and LQF of selected respirators in NaCl loading tests at 85 LPM. Table 7. Respirators’ pressure drops and NaCl LQF NaCl loading at 85 LPM CE 3 CE 1 EX 2 EX 1 EX 4 EX 11 Partial No Full Partial Partial Partial window Window Window window window window Flat Flat Flat Flat Wrinkled Wrinkled media media media media media media %Pen max during loading up to 30 mg 1.14 1.03 2.39 1.99 4.15 3.73 dP Initial (mmH2O) 26.8 7.6 13.3 12.2 9.5 6.2 dP Final (mmH2O), at 30 mg loading 102.4 12.1 25.2 22.7 19 12.6 dP rise, at 30 mg NaCl loading 75.6 4.55 11.9 10.5 9.5 6.4 NaCl LQF (mg / mmH2O / filter) 0.40 6.6 2.5 2.9 3.2 4.7

[0117] It is noted that there is a significant difference in loading performance between charged and non-charged media for respirators as indicated by LQF. CE 3 used non-charged media, resulting in a much higher initial pressure drop and pressure drop rise during loading that led to very low LQF when compared to other respirators that use charge media.

[0118] CE 1 was a control respirator with flat media and no window. It has a LQF of 6.6. EX 2 replaced the entire center panel of a CE 1 respirator that led to lower filtration area and hence lower LQF of about 2.5. EX 1 only replaced a portion of center panel of a CE 1 respirator and had a slightly higher LQF of 2.9. EX 4 and EX 11 incorporated wrinkled media hence had more surface area for loading and both had LQF higher than 3.

[0119] Wrinkled media F5 was used in above embodiments. However, it is expressly contemplated that other wrinkled media, with different materials, stretch ratio and / or filtrationperformance, may be used for respirators. FIG 7 illustrates various shapes of windows. It is desired to have window large enough to effectively show wearer's mouth movement for better communication. Too narrow or too low of window may not fulfill the purpose. The transparent window can have various designs and dimensions. It may also have marks or prints for labeling or coloring for differentiation purpose.

[0120] Transparent windows may be incorporated into a respirator in any suitable manner. For example, the window may be welded, point-welded, bonded, point-bonded, adhered with adhesive, or using any other suitable technique.

[0121] Optionally, a transparent breathing valve can be used in place of or as part of the transparent window for selected respirator applications.

[0122] Respirators having transparent window portions as described in embodiments herein include wrinkled media as one or more layers, panels or portions of a respirator body. The inclusion of wrinkled media increases a surface area of the respirator body, helping to mitigate the loss of surface area when a transparent portion is added. Respirators made in accordance with embodiments herein, therefore, exhibit a lower initial pressure drop and a higher quality factor (QF) and loading quality factor (LQF) than corresponding respirators comprising only flat media.

[0123] Horizontal tri-fold respirators made in accordance with embodiments herein, for example, may have an initial QF of at least 0.4 when a respirator body has a window portion replacing at least 40% of the center panel. In some cases, the initial QF of a horizontal tri-fold respirator having a window portion replacing at least 40% of the center panel may have an initial QF of at least 0.5. Horizontal trifold respirators having a window portion replacing at least 40% of the center panel may also experience an initial dP of no more than 12 mmH2O.

[0124] Horizontal tri-fold respirators made in accordance with embodiments herein may have an LQF of at least 2 for a respirator having a window portion covering at least 20% of the entire respirator body an initial dP of no more than 12 mmH2O.

[0125] Cup-shaped respirators made in accordance with embodiments herein may, for example, have an initial QF of at least 0.6 for a respirator having a window covering at least 30% of the respirator body, with an initial dP of no more than 10 mmH2O.

[0126] Cup-shaped respirators made in accordance with embodiments herein may, for example, have an initial QF of at least 0.8 for a respirator having a window covering at least 30% of the respirator body, with an initial dP of no more than 10 mmH2O.

[0127] FIG.8 illustrates a method of making a respiratory protection device in accordance with embodiments herein. Method 800 may be used to form respirators of any disposable respirator model that could benefit from a nose pad or face seal as described herein.

[0128] At block 810, respirator media is obtained. Wrinkled media 812 may be obtained for one or more layers or panels, such 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, as described in U.S. Provisional Application Number 63 / 610,995.

[0129] Flat media 814 may be obtained for one or more layers or panels. Other media 616 may also be used. As described herein, it is expressly contemplated that all layers of a respirator may be formed of wrinkled media 812 in order to increase a filtration area to compensate for the increased pressure drop that accompanies adding a transparent window.

[0130] Some respirators, in accordance with embodiments herein, may also include other media layers. For example, media with anti-fog properties may be obtained for a portion of the respirator. Alternatively, a shell layer may be used for some respirator models.

[0131] Respirator models described herein may be formed from multiple panels. In some embodiments, a first panel is formed of different media than a second panel.

[0132] At block 820, one or more treatments may be performed on one or more of the layers. For example, a cup shell may be pre-formed 822. One or more layers may be charged 824 to exhibit electret properties attracting and binding particulates and liquid droplets. Other treatments 826 may be performed.

[0133] 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.

[0134] 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 patternmay 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.

[0135] 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.

[0136] Treating respirator media may also include applying an anti-fog coating 826 to a window material. For example, a transparent polymeric material may be treated with an anti-fog coating prior to, or after, the window is placed within a panel. For example, a polyurethane with a hydrophilic additive may be coated onto a surface. An aqueous polymeric dispersion may be coated onto a surface, such as those described in U.S. Pat. No. 10,241,237, issued on March 26, 2019 or in U.S. Pat. No. 10,048,408, issued on August 14, 2018. The aqueous polymeric dispersion may be prepared as a latex, for example. The aqueous polymeric dispersion may be prepared as an alkaline pH stable latex. The aqueous polymeric dispersion may be prepared using a polyurethane polymer dispersion or an acrylic polymer dispersion, or a mixture thereof.

[0137] An antifog coating may be applied directly to a window material – e.g. a plastic material, at any suitable point during a manufacturing process. The antifog coating, in embodiments herein, is sufficiently transparent that a wearer’s mouth is visible. An antifog coating, in some embodiments herein, is transparent once applied.

[0138] The window material may comprise a stiff, flexible material. For example, a window may have substantially no stretchability to it. The plastic material preferably comprises transparent polymer film. The polymer film may be rigid, semi-rigid, or flexible / conformable or stretchable. Suitable materials for the polymer film include thermoplastic materials, such as thermoplastic polyurethanes such as those sold under the brand name Estane™ available from Lubrizol, and metallocene polyolefin elastomers such as those sold under the brand Engage™ available from Dow. Another useful material for the transparent polymer film includes polyethylene terephthalate (PET) such as Mylar™ film from DuPont Teijin. Other useful plastic materials include Clarifoil™ acetate clear films that are inherently anti-fog, those are available from Celanese. The window material may comprise curvature – e.g. to help conform to a wearer’s face. In some embodiments, the window material may comprise curvature in two directions – for example, a window for a cup-shaped respirator may have curvature in two directions. The window film thickness is at least 10 micrometers, at least 50 micrometer, at least 100 micrometers or at least 500 micrometers. The polymer film may be comprised of multiple layers wherein one or more layer may be pressure sensitive adhesive.

[0139] Transparent windows provide mechanical benefits to a respirator. Transparent windows provide some collapse resistance and assist in maintaining a distance of the respirator bodyaway from a wearer’s mouth. Transparent windows formed from stiff material may also help retain a shape of a respirator body.

[0140] 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.

[0141] At block 830, a layer stack is formed. The layer stack may be composed of one or more filter layers 832. Filter layers 832 may be wrinkled media and / or flat media layers. The layer stack may include a cover web 834. 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. One example of a sorbent often used in filtration is activated carbon. The layer with active carbon may be a wrinkled media layer. The active carbon layer may be a separate layer, e.g. with carbon or another suitable sorbent attached to the surface of fibrous web. Other layers 839 maybe present such as fluid resistant layers or stiffening layers. While active carbon is described here as one sorbent material, it is expressly contemplated that other sorbent materials may be suitable. For example, a polymeric sorbent could be used in embodiments herein.

[0142] At block 840, the layer stack is sealed. Sealing the layer stack may include applying a weld 842, seam 844, bond 846 or other suitable method 848 to couple two or more layers of respirator media. Additionally, while a weld 842 or bond 846 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 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.

[0143] In some embodiments, sealing a layer stack includes sealing a window portion into a respirator body or into a respirator panel.

[0144] At block 850, accessories are added. A nose clip 852 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 852 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.

[0145] In some embodiments, the transparent window is applied after the layer stack is sealed. For example, an aperture for the transparent window may be formed using any suitable cutting technique – die-cutting, ultrasonic cutting, laser-cutting, etc. The transparent window is then sealed to the respirator body. Sealing may be done in any suitable manner that sufficiently prevents the introduction of leakage area. Sealing may include applying adhesive, welding, bonding, point- bonding, stitching or another suitable sealing technique.

[0146] A nose foam 854 may also be added to increase comfort and improve seal. For example, custom nose foams are described in PCT Publication WO 2022 / 235472, published on November 10, 2022, however other foam types and positions are contemplated.

[0147] An exhalation valve 856 may be added. In some embodiments, a valve-containing portion of a respirator has less stretch than a valve-less portion. A harness 858, for holding the respirator in contact with a wearer’s face, may be applied. In some embodiments, the harness 858 includes straps or earloops that are integral to a wrinkled media layer of the respirator. In some embodiments, the harness 858 is a separate component welded, stapled, adhered or otherwise coupled to the respirator body. Other accessories 859 may also be added.

[0148] In accordance with embodiments herein

[0149] In some embodiments herein, a horizontal flat-fold respirator is provided with one or more fit features. 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 along a 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.

[0150] In some embodiments herein, a cup-style respirator is provided with one or more fit features. A cup-style respirator includes a respirator filter layer formed around or to a shell.

[0151] 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, incorporatedherein by reference, a duck-bill style respirator, such as that described in U.S. Pat 5,322,061 to Brunson.

[0152] In some embodiments herein, different portions of a respirator have different compositions. For example, a center panel may comprise wrinkled media with a lower pressure drop than a top and bottom panel, such that exhaled air is directed through the panel area around the window.

[0153] While respirators herein are illustrated as having white 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, types of wrinkled media used, etc.

[0154] 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 filament to form the seam, such that the elastic filament can stretch with the wrinkled media.

[0155] 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.

[0156] A horizontal flat-fold respirator is presented that includes a respirator body including: a layer of wrinkled media. The wrinkled media includes: a first series of substantially parallel non- bonded elastic filaments between a first and a second non-woven porous web. 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 respirator also includes a transparent portion. The horizontal flat-fold respirator is a high efficiency respirator.

[0157] The respirator may further include a top panel configured to seal around a nose of a user, a bottom panel configured to seal around a chin of a user, a center panel, the center panel includes a top edge and a bottom edge, the center panel seals to the top panel along the top edge, and the center panel seals to the bottom panel along the bottom edge. The top panel, bottom panel or center panel include the transparent portion.

[0158] The respirator may be implemented such that the center panel includes the transparent portion, and the center panel includes an outer diameter and an inner diameter, the transparent portion outer diameter is sealed to the center panel inner diameter.

[0159] The respirator may be implemented such that sealing includes welding, bonding, point bonding or stitching.

[0160] The respirator may be implemented such that the transparent portion includes a transparent polymeric material.

[0161] The respirator may be implemented such that the transparent portion includes plastic.

[0162] The respirator may be implemented such that the transparent portion is flexible.

[0163] The respirator may be implemented such that the transparent portion includes curvature.

[0164] The respirator may be implemented such that the respirator filters at least 95% of airborne particles that have a mass median aerodynamic diameter of 0.3 micrometers.

[0165] The respirator may be implemented such that the respirator filters at least 99% of airborne particles that have a mass median aerodynamic diameter of 0.3 micrometers.

[0166] The respirator may be implemented such that a first pressure drop across the respirator is less than a second pressure drop of a second horizontal flat fold respirator, identical in shape to the first horizontal flat fold respirator, the second horizontal flat fold respirator includes a second respirator body formed of flat filter media and having no transparent portion.

[0167] The respirator may also include sorbent particles.

[0168] The respirator may also include a cover web layer.

[0169] The respirator may also include: a nose clip, a nose foam, a valve, or a harness.

[0170] The respirator may be implemented such that one of the first and second nonwoven layers includes a membrane.

[0171] The respirator may be implemented such that one of the first and second nonwoven layers includes a fibrous nonwoven material.

[0172] The respirator may be implemented such that the transparent portion includes an anti- fog coating.

[0173] The respirator may be implemented such that the transparent portion has a perimeter that is substantially circular, ovular, or polygonal in shape.

[0174] The respirator may be implemented such that8, the substantially polygonal shape has a perimeter that is rectangular, pentagonal, hexagonal, heptagonal, octagonal, nonagonal or decagonal.

[0175] The respirator may be implemented such that the transparent portion is sized such that a mouth of a wearer is visible.

[0176] The respirator may be implemented such that the transparent portion is sized such that a mouth movement by the wearer is visible.

[0177] The respirator may be implemented such that the transparent portion is sized such that lip reading of a wearer is possible.

[0178] The respirator may be implemented such that the respirator filters out at least 80% of airborne particles having a diameter of 0.3 µm or higher.

[0179] The respirator may be implemented such that the respirator filters out at least 92% of airborne particles having a diameter of 0.3 µm or higher.

[0180] The respirator may be implemented such that the respirator filters out at least 95% of airborne particles having a diameter of 0.3 µm or higher.

[0181] The respirator may be implemented such that the respirator filters out at least 98% of airborne particles having a diameter of 0.3 µm or higher.

[0182] The respirator may be implemented such that the respirator filters out at least 99% of airborne particles having a diameter of 0.3 µm or higher.

[0183] The respirator may be implemented such that the transparent portion is a first transparent portion, and the respirator includes a second transparent portion.

[0184] The respirator may be implemented such that one of the top panel, bottom panel, and center panel include the first transparent portion, and wherein a different one of the top panel, bottom panel and center panel include the second transparent portion.

[0185] The respirator may be implemented such that a single panel includes the first and second transparent portions.

[0186] The respirator may be implemented such that the center panel includes the first and second transparent portions.

[0187] The respirator may be implemented such that the transparent portion comprises at least about 40% of the center panel, and the respirator has an initial quality factor of at least about 0.4, with an initial pressure drop of less than about 12 mmH2O.

[0188] The respirator may be implemented such that the transparent portion comprises at least about 40% of the center panel, and the respirator has an initial quality factor of at least about 0.5, with an initial pressure drop of less than about 12 mmH2O.

[0189] The respirator may be implemented such that the transparent portion comprises at least 20% of the respirator body, and the respirator has an initial quality factor of at least 0.35.

[0190] The respirator may be implemented such that the transparent portion comprises at least 20% of the respirator body, and wherein the respirator has an initial quality factor of at least 0.4.

[0191] The respirator may be implemented such that the transparent portion comprises at least 40% of the respirator body, and the respirator has an LQF of at least 2, with an initial pressure drop of less than about 12 mmH2O.

[0192] The respirator may be implemented such that the transparent portion comprises at least 40% of the respirator body, and the respirator has an LQF of at least 2.5, with an initial pressure drop of less than about 12 mmH2O.

[0193] The respirator may be implemented such that the transparent portion has a first portion, with a first light transmissivity, and a second portion, with a second light transmissivity, the second light transmissivity is greater than the first light transmissivity.

[0194]

[0195] A cup-shaped respirator is presented that includes a respirator body having a layer of wrinkled media. The wrinkled media includes a first series of substantially parallel non-bonded elastic filaments between a first and a second non-woven porous web, 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 respirator also includes a transparent portion sealed, along an outer diameter, to the respirator body, forming a window through the cup-shaped respirator, wherein the cup-shaped respirator is a high efficiency respiratory.

[0196] The respirator may include a formed portion that, in a first state, includes curvature in multiple directions.

[0197] The respirator may be implemented such that the respirator body is resilient such that the curvature recovers after a force is applied to the curvature.

[0198] The respirator may also include a shell layer.

[0199] The respirator may be implemented such that the shell layer is an outer layer.

[0200] The respirator may be implemented such that the shell layer is an inner layer.

[0201] The respirator may be implemented such that the shell layer includes a reticulated material.

[0202] The respirator may be implemented such that the shell layer includes dashed-line slits.

[0203] The respirator may be implemented such that the shell layer includes an elastic net.

[0204] The respirator may be implemented such that sealing includes welding, bonding, point bonding or stitching.

[0205] The respirator may be implemented such that the transparent portion includes a transparent polymeric material.

[0206] The respirator may be implemented such that the transparent portion includes plastic.

[0207] The respirator may be implemented such that the transparent portion is flexible.

[0208] The respirator may be implemented such that the transparent portion includes curvature in two directions.

[0209] The respirator may be implemented such that the cup-shaped respirator filters at least 95% of airborne particles that have a mass median aerodynamic diameter of 0.3 micrometers.

[0210] The respirator may be implemented such that the cup-shaped respirator filters at least 99% of airborne particles that have a mass median aerodynamic diameter of 0.3 micrometers.

[0211] The respirator may be implemented such that a first pressure drop across the respirator is less than a second pressure drop of a second cup-shaped respirator, identical in shape to the first cup-shaped respirator body, the second cup-shaped respirator includes a second cup-shaped respirator body formed of flat filter media and having no transparent portion.

[0212] The respirator may also include a sorbent particles.

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

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

[0215] The respirator may be implemented such that the transparent portion includes an anti- fog coating.

[0216] The respirator may be implemented such that the transparent portion has a perimeter that is substantially circular, ovular, or polygonal in shape.

[0217] The respirator may be implemented such that the substantially polygonal shape has a perimeter that is rectangular, pentagonal, hexagonal, heptagonal, octagonal, nonagonal or decagonal.

[0218] The respirator may be implemented such that the transparent portion is sized such that a mouth of a wearer is visible.

[0219] The respirator may be implemented such that the transparent portion is sized such that a mouth movement by the wearer is visible.

[0220] The respirator may be implemented such that the transparent portion is sized such that lip reading of a wearer is possible.

[0221] The respirator may be implemented such that the respirator filters out at least 80% of airborne particles having a diameter of 0.3 µm or higher.

[0222] The respirator may be implemented such that the respirator filters out at least 92% of airborne particles having a diameter of 0.3 µm or higher.

[0223] The respirator may be implemented such that the respirator filters out at least 95% of airborne particles having a diameter of 0.3 µm or higher.

[0224] The respirator may be implemented such that the respirator filters out at least 98% of airborne particles having a diameter of 0.3 µm or higher.

[0225] The respirator may be implemented such that the respirator filters out at least 99% of airborne particles having a diameter of 0.3 µm or higher.

[0226] The respirator may be implemented such that the transparent portion is a first transparent portion, and the respirator includes a second transparent portion.

[0227] The respirator may be implemented such that the first transparent portion has a first light transmissivity, the second transparent portion has a second light transmissivity and wherein the first and second light transmissivities differ.

[0228] The respirator may be implemented such that the first and second transparent portions share an edge.

[0229] The respirator may be implemented such that the transparent portion comprises at least about 30% of the center panel, and wherein the respirator has an initial quality factor of at least about 0.6, with an initial pressure drop of less than about 10 mmH2O.

[0230] The respirator may be implemented such that the transparent portion comprises at least about 30% of the center panel, and wherein the respirator has an initial quality factor of at least about 0.8, with an initial pressure drop of less than about 10 mmH2O.The respirator may be implemented such that the transparent portion has a first portion, with a first light transmissivity, and a second portion, with a second light transmissivity, the second light transmissivity is greater than the first light transmissivity.

[0231] A vertical fold respirator is presented that includes a layer of wrinkled media. The wrinkled media includes: a first series of substantially parallel non-bonded elastic filaments between a first and a second non-woven porous fibrous web, 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. The respirator includes a transparent portion sealed, along an outer diameter, to a panel of the vertical fold respirator, forming a window through the vertical fold respirator, wherein the vertical fold respirator is a high efficiency respirator.

[0232] The respirator may be implemented such that sealing includes welding, bonding, point bonding or stitching.

[0233] The respirator may be implemented such that the transparent portion includes a transparent polymeric material.

[0234] The respirator may be implemented such that the transparent portion includes plastic.

[0235] The respirator may be implemented such that the transparent portion is flexible.

[0236] The respirator may be implemented such that the transparent portion includes curvature.

[0237] The respirator may be implemented such that the respirator filters at least 95% of airborne particles that have a mass median aerodynamic diameter of 0.3 micrometers.

[0238] The respirator may be implemented such that the respirator filters at least 99% of airborne particles that have a mass median aerodynamic diameter of 0.3 micrometers.

[0239] The respirator may be implemented such that a first pressure drop across the respirator is less than a second pressure drop of a second vertical flat fold respirator, identical in shape to the first vertical flat fold respirator, the second vertical flat fold respirator includes a second respirator body formed of flat filter media and having no transparent portion.

[0240] The respirator may be implemented such that the respirator is configured to fold flat along a centerline.

[0241] The respirator may also include sorbent particles.

[0242] The respirator may also include a cover web layer.

[0243] The respirator may also include: a nose clip, a nose foam, a valve, or a harness.

[0244] The respirator may be implemented such that the transparent portion includes an anti- fog coating.

[0245] The respirator may be implemented such that the transparent portion has a perimeter that is substantially circular, ovular, or polygonal in shape.

[0246] The respirator may be implemented such that8, the substantially polygonal shape has a perimeter that is rectangular, pentagonal, hexagonal, heptagonal, octagonal, nonagonal or decagonal.

[0247] The respirator may be implemented such that the transparent portion is sized such that a mouth of a wearer is visible.

[0248] The respirator may be implemented such that the transparent portion is sized such that a mouth movement by the wearer is visible.

[0249] The respirator may be implemented such that the transparent portion is sized such that lip reading of a wearer is possible.

[0250] The respirator may be implemented such that the respirator filters out at least 80% of airborne particles having a diameter of 0.3 µm or higher.

[0251] The respirator may be implemented such that the respirator filters out at least 92% of airborne particles having a diameter of 0.3 µm or higher.

[0252] The respirator may be implemented such that the respirator filters out at least 95% of airborne particles having a diameter of 0.3 µm or higher.

[0253] The respirator may be implemented such that the respirator filters out at least 98% of airborne particles having a diameter of 0.3 µm or higher.

[0254] The respirator may be implemented such that the respirator filters out at least 99% of airborne particles having a diameter of 0.3 µm or higher.

[0255] The respirator may be implemented such that the transparent portion is a first transparent portion, and the respirator includes a second transparent portion.

[0256] The respirator may be implemented such that wherein the respirator comprises a first panel and a second panel, and wherein the first panel comprises the first transparent portion, and wherein the second panel comprises the second transparent portion.

[0257] The respirator may be implemented such that a single panel of the respirator comprises the first and second transparent portions.

[0258] The respirator may be implemented such that the first and second transparent portions are spaced apart.

[0259] The respirator may be implemented such that the transparent portion has a first portion, with a first light transmissivity, and a second portion, with a second light transmissivity, the second light transmissivity is greater than the first light transmissivity.

[0260] A duckbill respirator is presented that includes a layer of wrinkled media. The wrinkled media includes: a first series of substantially parallel non-bonded elastic filaments between a first and a second non-woven porous fibrous web. 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. The respirator also includes a transparent portion sealed, along an outer diameter to a portion of a respirator body, forming a window through the duckbill respirator, wherein the duckbill respirator is a high efficiency respirator.

[0261] The respirator may further include: the respirator is configured to fold flat along a centerline.

[0262] The respirator may also include: a first generally trapezoidal portion configured to contact a nose of a wearer and 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 sealing includes welding, bonding, point bonding or stitching.

[0264] The respirator may be implemented such that the transparent portion includes a transparent polymeric material.

[0265] The respirator may be implemented such that the transparent portion includes plastic.

[0266] The respirator may be implemented such that the transparent portion is flexible.

[0267] The respirator may be implemented such that the transparent portion includes curvature.

[0268] The respirator may be implemented such that the respirator filters at least 95% of airborne particles that have a mass median aerodynamic diameter of 0.3 micrometers.

[0269] The respirator may be implemented such that the respirator filters at least 99% of airborne particles that have a mass median aerodynamic diameter of 0.3 micrometers.

[0270] The respirator may be implemented such that a first pressure drop across the respirator is less than a second pressure drop of a second duckbill respirator, identical in shape to the first duckbill respirator, the second duckbill respirator includes a second respirator body formed of flat filter media and having no transparent portion.

[0271] The respirator may also include sorbent particles.

[0272] The respirator may also include a cover web layer.

[0273] The respirator may also include: a nose clip, a nose foam, a valve, or a harness.

[0274] The respirator may be implemented such that one of the first and second nonwoven layers includes a membrane.

[0275] The respirator may be implemented such that one of the first and second nonwoven layers includes a fibrous nonwoven material.

[0276] The respirator may be implemented such that the transparent portion includes an anti- fog coating.

[0277] The respirator may be implemented such that the transparent portion has a perimeter that is substantially circular, ovular, or polygonal in shape.

[0278] The respirator may be implemented such that the substantially polygonal shape has a perimeter that is rectangular, pentagonal, hexagonal, heptagonal, octagonal, nonagonal or decagonal.

[0279] The respirator may be implemented such that the transparent portion is sized such that a mouth of a wearer is visible.

[0280] The respirator may be implemented such that the transparent portion is sized such that a mouth movement by the wearer is visible.

[0281] The respirator may be implemented such that the transparent portion is sized such that lip reading of a wearer is possible.

[0282] The respirator may be implemented such that the respirator filters out at least 80% of airborne particles having a diameter of 0.3 µm or higher.

[0283] The respirator may be implemented such that the respirator filters out at least 92% of airborne particles having a diameter of 0.3 µm or higher.

[0284] The respirator may be implemented such that the respirator filters out at least 95% of airborne particles having a diameter of 0.3 µm or higher.

[0285] The respirator may be implemented such that the respirator filters out at least 98% of airborne particles having a diameter of 0.3 µm or higher.

[0286] The respirator may be implemented such that the respirator filters out at least 99% of airborne particles having a diameter of 0.3 µm or higher.

[0287] The respirator may be implemented such that the transparent portion is a first transparent portion, and the respirator includes a second transparent portion.

[0288] The respirator may be implemented such that one of the top panel, bottom panel, and center panel include the first transparent portion, and wherein a different one of the top panel, bottom panel and center panel include the second transparent portion.

[0289] The respirator may be implemented such that a single panel includes the first and second transparent portions.

[0290] The respirator may be implemented such that the center panel includes the first and second transparent portions.

[0291] The respirator may be implemented such that the transparent portion has a first portion, with a first light transmissivity, and a second portion, with a second light transmissivity, the second light transmissivity is greater than the first light transmissivity.

[0292] A pleated respirator is presented that includes a layer of wrinkled media. The wrinkled media includes a first series of substantially parallel non-bonded elastic filaments between a first and a second non-woven porous fibrous web. 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. The respirator includes a transparent portion sealed, along an outer diameter, to a respirator body of the pleated respirator, forming a window through the pleated respirator, and wherein the pleated respirator is a high-efficiency respirator.

[0293] 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

[0294] The respirator may be implemented such that the respirator is configured to fold flat along a centerline.

[0295] The respirator may be implemented such that sealing includes welding, bonding, point bonding or stitching.

[0296] The respirator may be implemented such that the transparent portion includes a transparent polymeric material.

[0297] The respirator may be implemented such that the transparent portion includes plastic.

[0298] The respirator may be implemented such that the transparent portion is flexible.

[0299] The respirator may be implemented such that the transparent portion includes curvature.

[0300] The respirator may be implemented such that the respirator filters at least 95% of airborne particles that have a mass median aerodynamic diameter of 0.3 micrometers.

[0301] The respirator may be implemented such that the respirator filters at least 99% of airborne particles that have a mass median aerodynamic diameter of 0.3 micrometers.

[0302] The respirator may be implemented such that a first pressure drop across the respirator is less than a second pressure drop of a second pleated respirator, identical in shape to the first pleated respirator, the second pleated respirator includes a second respirator body formed of flat filter media and having no transparent portion.

[0303] The respirator may be implemented such that the transparent portion includes an antifog coating.

[0304] The respirator may be implemented such that the transparent portion has a perimeter that is substantially circular, ovular, or polygonal in shape.

[0305] The respirator may be implemented such that8, the substantially polygonal shape has a perimeter that is rectangular, pentagonal, hexagonal, heptagonal, octagonal, nonagonal or decagonal.

[0306] The respirator may be implemented such that the transparent portion is sized such that a mouth of a wearer is visible.

[0307] The respirator may be implemented such that the transparent portion is sized such that a mouth movement by the wearer is visible.

[0308] The respirator may be implemented such that the transparent portion is sized such that lip reading of a wearer is possible.

[0309] The respirator may be implemented such that the respirator filters out at least 80% of airborne particles having a diameter of 0.3 µm or higher.

[0310] The respirator may be implemented such that the respirator filters out at least 92% of airborne particles having a diameter of 0.3 µm or higher.

[0311] The respirator may be implemented such that the respirator filters out at least 95% of airborne particles having a diameter of 0.3 µm or higher.

[0312] The respirator may be implemented such that the respirator filters out at least 98% of airborne particles having a diameter of 0.3 µm or higher.

[0313] The respirator may be implemented such that the respirator filters out at least 99% of airborne particles having a diameter of 0.3 µm or higher.

[0314] The respirator may be implemented such that the transparent portion is a first transparent portion, and the respirator includes a second transparent portion.

[0315] The respirator may be implemented such that the transparent portion has a first portion, with a first light transmissivity, and a second portion, with a second light transmissivity, the second light transmissivity is greater than the first light transmissivity.

[0316] A method of making a disposable respirator is presented that includes obtaining a wrinkled media article, forming a stack of media layers, wherein the wrinkled media article is a wrinkled layer within the stack of media layers, wherein at least one layer of media layers is a high- efficiency filtering layer, and sealing the stack of media layers. The disposable respirator comprises a transparent portion sealed to a body of the respirator, wherein the transparent portion is positioned such that, when worn, a mouth of a wearer is visible through the respirator.

[0317] The method may also include: preforming the stack of media layers, wherein preforming forms the stack of media layers into a cup-shape.

[0318] The method may also include: removing a portion of the sealed stack of media layers, and sealing the transparent portion to the sealed stack of media layers such that an outer perimeter of the transparent portion is sealed to an inner perimeter of the sealed stack of media layers.

[0319] The method may be implemented such that the transparent portion includes plastic.

[0320] The method may be implemented such that the transparent portion is flexible.

[0321] The method may be implemented such that the transparent portion is inelastic.

[0322] The method may be implemented such that the transparent portion includes curvature.

[0323] The method may be implemented such that the respirator filters at least 95% of airborne particles that have a mass median aerodynamic diameter of 0.3 micrometers.

[0324] The method may be implemented such that the respirator filters at least 99% of airborne particles that have a mass median aerodynamic diameter of 0.3 micrometers.

[0325] The method may be implemented such that a first pressure drop across the respirator is less than a second pressure drop of a second respirator, identical in shape to the respirator, the second respirator includes a second respirator body formed of flat filter media and having no transparent portion.

[0326] The method may also include: removing an inner portion of the sealed stack of layers, and sealing the transparent portion to the stack of layers, in place of the inner portion.

[0327] The method may be implemented such that removing includes die-cutting, laser- cutting, or ultrasonic cutting.

[0328] The method may be implemented such that the stack of layers includes the transparent portion.

[0329] The method may be implemented such that the stack of layers includes sorbent particles.

[0330] The method may be implemented such that the stack of layers includes a cover web.

[0331] The method may be implemented such that the wrinkled media article is configured to stretch, from a resting length to a stretched length, and the stretched length is at least 10% longer than the resting length.

[0332] The method may be implemented such that the sealed stack of media layers having the transparent portion is configured to stretch, from a resting length to a stretched length, and the stretched length is at least 10% longer than a resting length.

[0333] The method may be implemented such that one layer of the stack of media layers includes a shell layer.

[0334] The method may be implemented such that the shell layer is an outer layer with respect to the wrinkled layer.

[0335] The method may be implemented such that the shell layer is an inner layer with respect to the wrinkled layer.

[0336] The method may be implemented such that the shell layer includes a reticulated open mesh, dashed-line slits, or an extruded net.

[0337] The method may be implemented such that the shell layer has a resting shape and, after a force deforms the resting shape, recovers to the resting shape.

[0338] The method may also include: adding one of a nose clip, a nose foam , a valve, or a harness to the stack of media layers before or after sealing.

[0339] The method may be implemented such that sealing includes welding, point-welding, bonding, or point-bonding, or forming a seam.

[0340] The method may also include charging the wrinkled filter layer.

[0341] The method may include charging all additional filter layers of the respirator.

[0342] The method may be implemented such that the respirator is a horizontal tri-fold respirator.

[0343] The method may be implemented such that the respirator is a vertical fold respirator.

[0344] The method may be implemented such that the respirator is a cup-shape respirator.

[0345] The method may be implemented such that the respirator is a pleated respirator.

[0346] The method may be implemented such that the respirator is a duck-bill respirator.

[0347] The method may be implemented such that one of the first and second nonwoven layers includes a membrane.

[0348] The method may be implemented such that one of the first and second nonwoven layers includes a fibrous nonwoven material.

[0349] The respirator may be implemented such that the transparent portion has a perimeter that is substantially circular, ovular, or polygonal in shape.

[0350] The respirator may be implemented such that the substantially polygonal shape has a perimeter that is rectangular, pentagonal, hexagonal, heptagonal, octagonal, nonagonal or decagonal.

[0351] The respirator may be implemented such that the transparent portion is sized such that a mouth of a wearer is visible.

[0352] The respirator may be implemented such that the transparent portion is sized such that a mouth movement by the wearer is visible.

[0353] The respirator may be implemented such that the transparent portion is sized such that lip reading of a wearer is possible.

[0354] The respirator may be implemented such that the respirator filters out at least 80% of airborne particles having a diameter of 0.3 µm or higher.

[0355] The respirator may be implemented such that the respirator filters out at least 92% of airborne particles having a diameter of 0.3 µm or higher.

[0356] The respirator may be implemented such that the respirator filters out at least 95% of airborne particles having a diameter of 0.3 µm or higher.

[0357] The respirator may be implemented such that the respirator filters out at least 98% of airborne particles having a diameter of 0.3 µm or higher.

[0358] The respirator may be implemented such that the respirator filters out at least 99% of airborne particles having a diameter of 0.3 µm or higher.

[0359] The respirator may be implemented such that the transparent portion is a first transparent portion, and the respirator includes a second transparent portion.

[0360] The respirator may be implemented such that one of the top panel, bottom panel, and center panel include the first transparent portion, and wherein a different one of the top panel, bottom panel and center panel include the second transparent portion.

[0361] The respirator may be implemented such that a single panel includes the first and second transparent portions.

[0362] The respirator may be implemented such that the center panel includes the first and second transparent portions.

[0363] The respirator may be implemented such that the transparent portion includes at least 20% of the respirator body, and the respirator has an initial quality factor of at least 0.35.

[0364] The respirator may be implemented such that the transparent portion includes at least 20% of the respirator body, and the respirator has an initial quality factor of at least 0.4.

[0365] The respirator may be implemented such that the transparent portion has a first portion, with a first light transmissivity, and a second portion, with a second light transmissivity, the second light transmissivity is greater than the first light transmissivity.

[0366] A respirator including a layer of wrinkled media is presented. The layer of wrinkled media having a transparent window sealed to a body of the respirator such that a mouth of a wearer of the respirator is visible through the transparent window, wherein the respirator is a high-efficiency respirator.

[0367] 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.

[0368] The respirator may be implemented such that the layer of wrinkled media includes:

[0369] a first series of substantially parallel non-bonded elastic filaments between a first and a second non-woven porous fibrous web,

[0370] the first non-woven porous fibrous web is directly bonded to the second non-woven porous fibrous web,

[0371] wherein at least one portion of the wrinkled media is resiliently extensible under tension.

[0372] The respirator may be implemented such that the transparent window seal includes a weld, a bond, a point bond or a seam.

[0373] The respirator may be implemented such that the transparent window includes a transparent polymeric material.

[0374] The respirator may be implemented such that the transparent window includes plastic.

[0375] The respirator may be implemented such that the transparent window includes a flexible material.

[0376] The respirator may be implemented such that the transparent window includes curvature.

[0377] The respirator may be implemented such that the respirator filters at least 95% of airborne particles that have a mass median aerodynamic diameter of 0.3 micrometers.

[0378] The respirator may be implemented such that the respirator filters at least 99% of airborne particles that have a mass median aerodynamic diameter of 0.3 micrometers.

[0379] The respirator may be implemented such that a first pressure drop across the respirator is less than a second pressure drop of a second respirator, identical in shape to the first respirator, the second respirator includes a second respirator body formed of flat filter media and having no transparent window.

[0380] The respirator may also include sorbent particles.

[0381] The respirator may also include a cover web layer.

[0382] The respirator may also include: a nose clip, a nose foam, a valve, or a harness.

[0383] The respirator may be implemented such that one of the first and second nonwoven layers includes a membrane.

[0384] The respirator may be implemented such that one of the first and second nonwoven layers includes a fibrous nonwoven material.

[0385] The respirator may also include a shell layer.

[0386] The respirator may be implemented such that the shell layer is an outer layer.

[0387] The respirator may be implemented such that the shell layer is an inner layer.

[0388] The respirator may be implemented such that the shell layer includes a reticulated material, dashed-line slits or an elastic net.

[0389] The respirator may also include a sorbent layer.

[0390] The respirator may also include a cover web layer.

[0391] The respirator may also include: a nose clip, a foam layer, a valve, or a harness.

[0392] The respirator may also include a strap, and the strap, in combination with the layer of wrinkled media, forms a unitary wrinkled media article.

[0393] The respirator may be implemented such that the respirator is a horizontal tri-fold respirator.

[0394] The respirator may be implemented such that the respirator is a vertical fold respirator.

[0395] The respirator may be implemented such that the respirator is a duck-bill respirator.

[0396] The respirator may be implemented such that the respirator is a cup-shaped respirator.

[0397] The respirator may be implemented such that the respirator is a pleated respirator.

[0398] The respirator may be implemented such that one of the first and second nonwoven layers includes a membrane.

[0399] The respirator may be implemented such that one of the first and second nonwoven layers includes a fibrous nonwoven material.

[0400] The respirator may be implemented such that the transparent portion has a perimeter that is substantially circular, ovular, or polygonal in shape.

[0401] The respirator may be implemented such that8, the substantially polygonal shape has a perimeter that is rectangular, pentagonal, hexagonal, heptagonal, octagonal, nonagonal or decagonal.

[0402] The respirator may be implemented such that the transparent portion is sized such that a mouth of a wearer is visible.

[0403] The respirator may be implemented such that the transparent portion is sized such that a mouth movement by the wearer is visible.

[0404] The respirator may be implemented such that the transparent portion is sized such that lip reading of a wearer is possible.

[0405] The respirator may be implemented such that the respirator filters out at least 80% of airborne particles having a diameter of 0.3 µm or higher.

[0406] The respirator may be implemented such that the respirator filters out at least 92% of airborne particles having a diameter of 0.3 µm or higher.

[0407] The respirator may be implemented such that the respirator filters out at least 95% of airborne particles having a diameter of 0.3 µm or higher.

[0408] The respirator may be implemented such that the respirator filters out at least 98% of airborne particles having a diameter of 0.3 µm or higher.

[0409] The respirator may be implemented such that the respirator filters out at least 99% of airborne particles having a diameter of 0.3 µm or higher.

[0410] The respirator may be implemented such that the transparent portion is a first transparent portion, and the respirator includes a second transparent portion.

[0411] The respirator may be implemented such that one of the top panel, bottom panel, and center panel include the first transparent portion, and wherein a different one of the top panel, bottom panel and center panel include the second transparent portion.

[0412] The respirator may be implemented such that a single panel includes the first and second transparent portions.

[0413] The respirator may be implemented such that the center panel includes the first and second transparent portions.

[0414] The respirator may be implemented such that the transparent portion includes at least 20% of the respirator body, and the respirator has an initial quality factor of at least 0.35.

[0415] The respirator may be implemented such that the transparent portion includes at least 20% of the respirator body, and the respirator has an initial quality factor of at least 0.4.

[0416] The respirator may be implemented such that the transparent portion has a first portion, with a first light transmissivity, and a second portion, with a second light transmissivity, the second light transmissivity is greater than the first light transmissivity.

Claims

What is claimed is:

1. A horizontal flat-fold respirator comprising: a respirator body comprising: a layer of wrinkled media, wherein the wrinkled media comprises: a first series of substantially parallel non-bonded elastic filaments between a first and a second non-woven porous web, 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; a transparent portion; and wherein the horizontal flat-fold respirator is a high efficiency respirator.

2. A cup-shaped respirator comprising: a respirator body comprising: a layer of wrinkled media, wherein the wrinkled media comprises: a first series of substantially parallel non-bonded elastic filaments between a first and a second non-woven porous web, 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; a transparent portion sealed, along an outer diameter, to the l respirator body, forming a window through the cup-shaped respirator, wherein the cup-shaped respirator is a high efficiency respiratory.

3. A vertical 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 and a second non-woven porous fibrous web; 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;a transparent portion sealed, along an outer diameter, to a panel of the vertical fold respirator, forming a window through the vertical fold respirator, wherein the vertical fold respirator is a high efficiency respirator.

4. A duckbill 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 and a second non-woven porous fibrous web; 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; and a transparent portion sealed, along an outer diameter to a portion of a respirator body, forming a window through the duckbill respirator, wherein the duckbill respirator is a high efficiency respirator.

5. 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 and a second non-woven porous fibrous web; 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; and a transparent portion sealed, along an outer diameter, to a respirator body of the pleated respirator, forming a window through the pleated respirator, and wherein the pleated respirator is a high-efficiency respirator.

6. A method of making a high-efficiency disposable respirator, the method comprising: obtaining a wrinkled media article; forming a stack of media layers, wherein the wrinkled media article is a wrinkled layer within the stack of media layers, wherein at least one layer of media layers is a high- efficiency filtering layer; sealing the stack of media layers; and wherein the disposable respirator comprises a transparent portion sealed to a body of the respirator, wherein the transparent portion is positioned such that, when worn, a mouth of a wearer is visible through the respirator.

7. The method of claim 6, and further comprising: preforming the stack of media layers, wherein preforming forms the stack of media layers into a cup-shape.

8. The method of claim 6 or 7, and further comprising: removing a portion of the sealed stack of media layers; and sealing the transparent portion to the sealed stack of media layers such that an outer perimeter of the transparent portion is sealed to an inner perimeter of the sealed stack of media layers.

9. The method of any of claims 6-8, wherein the transparent portion is flexible.

10. The method of any of claims 6-9, wherein the respirator filters at least 95% of airborne particles that have a mass median aerodynamic diameter of 0.3 micrometers.

11. The method of any of claims 6-10, and further comprising: removing an inner portion of the sealed stack of layers; and sealing the transparent portion to the stack of layers, in place of the inner portion.

12. The method of claim 11, wherein removing comprises die-cutting, laser-cutting, or ultrasonic cutting.

13. The method of any of claims 6-12, wherein the stack of layers comprises the transparent portion.

14. The method of any of claims 6-13, wherein the wrinkled media article is configured to stretch, from a resting length to a stretched length, and wherein the stretched length is at least 10% longer than the resting length.

15. The method of any of claims 6-14, wherein the sealed stack of media layers having the transparent portion is configured to stretch, from a resting length to a stretched length, and wherein the stretched length is at least 10% longer than a resting length.

16. The method of any of claims 6-15, wherein one layer of the stack of media layers comprises a shell layer.

17. The method of claim 16, wherein the shell layer has a resting shape and, after a force deforms the resting shape, recovers to the resting shape.

18. The method of claim 6, wherein sealing comprises welding, point-welding, bonding, or point- bonding, or forming a seam.

19. The method of any of claims 6-18, and further comprising charging the wrinkled filter layer.

20. The method of any of claims 6-19, wherein the respirator is a horizontal tri-fold respirator, a vertical fold respirator, a cup-shaped respirator, a pleated respirator, or a duck-bill respirator.

21. The respirator of any of claims 6-20, wherein the transparent portion is sized such that a mouth of a wearer is visible.

22. The respirator of any of claims 6-21, wherein the transparent portion is sized such that lip reading of a wearer is possible.

23. The respirator of any of claims 6-22, wherein the respirator filters out at least 80% of airborne particles having a diameter of 0.3 µm or higher.

24. The respirator of any of claims 6-23, wherein the transparent portion comprises at least 20% of the respirator body, and wherein the respirator has an initial quality factor of at least 0.

35.

25. A respirator comprising a layer of wrinkled media, the layer of wrinkled media having a transparent window sealed to a body of the respirator such that a mouth of a wearer of the respirator is visible through the transparent window, wherein the respirator is a high-efficiency respirator.

26. The respirator of claim 25, wherein the respirator can be stretched from a resting height to a stretched height, and recover to the resting height, and wherein the stretched height is at least 10% longer than the resting height.

27. The respirator of claim 25 or 26, wherein the layer of wrinkled media comprises: a first series of substantially parallel non-bonded elastic filaments between a first and a second non-woven porous fibrous web, wherein the first non-woven porous fibrous web is directly bonded to the second non-woven porous fibrous web, wherein at least one portion of the wrinkled media is resiliently extensible under tension.

28. The respirator of any of claims 25-27, wherein the transparent window comprises a transparent polymeric material.

29. The respirator of any of claims 25-28, wherein the transparent window comprises curvature.

30. The respirator of any of claims 25-29, wherein the respirator filters at least 95% of airborne particles that have a mass median aerodynamic diameter of 0.3 micrometers.

31. The respirator of any of claims 25-30, wherein a first pressure drop across the respirator is less than a second pressure drop of a second respirator, identical in shape to the first respirator, wherein the second respirator comprises a second respirator body formed of flat filter media and having no transparent window.

32. The respirator of any of claims 25-31, and further comprising a shell layer.

33. The respirator of any of claims 25-32, and also comprising a strap, and wherein the strap, in combination with the layer of wrinkled media, forms a unitary wrinkled media article.

34. The respirator of any of claims 25-33, wherein the respirator is a horizontal tri-fold respirator, a vertical fold respirator, a duck-bill respirator, a cup-shaped respirator, or a pleated respirator.

35. The respirator of any of claims 25-34, wherein one of the first and second nonwoven layers comprises a membrane.

36. The respirator of any of claims 25-35, wherein one of the first and second nonwoven layers comprises a fibrous nonwoven material.

37. The respirator of any of claims 25-36, wherein the transparent portion has a perimeter that is substantially circular, ovular, or polygonal in shape.

38. The respirator of any of claims 25-37, wherein the transparent portion is sized such that a mouth of a wearer is visible.

39. The respirator of any of claims 25-38, wherein the respirator filters out at least 80% of airborne particles having a diameter of 0.3 µm or higher.

40. The respirator of any of claims 25-39, wherein the transparent portion comprises at least 20% of the respirator body, and wherein the respirator has an initial quality factor of at least 0.35.

Images