Respiratory protection devices and methods of manufacturing the same

Abstract

A disposable respirator is presented that includes a layer of wrinkled media. The wrinkled media includes: a first series of substantially parallel non-bonded elastic material 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 fit feature including wrinkled media.

Description

RESPIRATORY PROTECTION DEVICES AND METHODS OF MANUFACTURING THESAMETECHNICAE FIELD

[0001] Respiratory devices designed with wrinkled expandable filter media used as face seal and / or nose pad that enable enhanced fit and comfort to the wearer. Respiratory devices designed with wrinkled expandable filter media that enable elasticity, low pressure drops and high particulate loading capacity, which reduce breathing resistance and provide enhanced comfort and fit to the wearer.SUMMARY

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

[0003] A disposable respirator is presented that includes a layer of wrinkled media. The wrinkled media includes: a first series of substantially parallel non-bonded elastic material 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 fit feature including wrinkled media

[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-4D illustrate a cup-shaped respirator with a nose pad in accordance with embodiments herein.

[0009] FIGS. 5A-5D illustrate a horizontal trifold respirator with a nose pad in accordance with embodiments herein.

[0010] FIGS. 6A-6D illustrate nose pads in accordance with embodiments herein.

[0011] FIGS. 7A-7K illustrate cup-shape respirators with and without face seals in accordance with embodiments herein.

[0012] FIG. 8 illustrates a method of forming a respirator having a fit feature in accordance with embodiments herein.

[0013] FIGS. 9A-9B illustrates a comparison of internal temperatures of respirators having different surface areas.

[0014] 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

[0015] 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).

[0016] 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.).

[0017] 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.).

[0018] 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.

[0019] 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.

[0020] 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. They may be disposed of after one-time use, or one day, or one week, or a longer period of time. Some barriers for disposable respirator use and compliance include user comfort while wearing a respirator and respirator fit.

[0021] There are many different configurations of disposable respirators in the market. The vast majority of them however have fixed shapes and dimensions that do not stretch to accommodate the wearers’ facial movement such as yawning, laughing or talking as well as desired. In some cases, the respirator may slide or move with wearer’s facial movement that lead to poor fit and leaks or even scratches to wear’s face. A few respirator designs that do offer stretch flexibility either involve bulkyplastic structure that may be heavy or have limited stretchability with extra filter media. Described in embodiments herein are flexible, stretchable and resilient fit features that can be used with a number of respirator models. Such fit features may assist in enabling different respirator models to accommodate a larger range of face sizes, potentially increasing respirator compliance rates in workplaces.

[0022] Respirator fit also concerns whether a respirator adequately seals to a wearer’s face. One example area of concern is the bridge of the nose. Nose cushions have been described in PCT publication WO 2022 / 235472, published on Nov. 10, 2022, as well as in US PAP 2008 / 0099022, published May 1, 2008. However, the described nose cushions are not stretchable. U.S. Pat. 10,136,687, issued on Nov. 27, 2018, describes a nose notch or void area that receives the user’s nose, but is limited to a single fixed shape and, therefore, is only helpful for a limited range of nose bridge height and width.

[0023] PCT publication WO 2014 / 110075, published Jul. 17, 2014, describes a face seal, but the face seal is not stretchable and is not formed of filtering material.

[0024] Respirator fit features are desired that improve a fit of a disposable respirator for a wearer, and increase a fit range of face sizes and profiles - e.g. fit features herein improve a respirator fit for an individual, and increase the number of individuals for whom a respirator can be used.

[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 on April 13, 2023 provides both a larger surface area than flat sheet media while maintaining more compact or lower profile than pleat pack with good conformity.

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

[0028] In some embodiments, fit features include a nose pad that allows for active stretching and contracting as a wearer’s face and head move, maintaining contact and a good seal. Nose pads in embodiments herein are formed of filtration media that has the same or higher filtration performanceof the body of the respirator, such that penetration of aerosols will not reduce an FFR’s efficiency rating. Nose pads in embodiments herein exhibit a low contact pressure, increasing comfort to a user.

[0029] Traditional nose pads or cushions are often supplied in a reel form for application in either a machine or cross-machine direction. A number of splices (e.g., joining of lengths of foam to make a longer length) is limited, which impacts manufacturing productivity. Wrinkled media is self- supporting and provides the required compliance to ensure a fit around the nose, allowing for application of splice-free continuous lengths.

[0030] In some embodiments, fit features include a face seal made of wrinkled media having a low contact pressure as well as the same or higher filtration performance as the media used for the respirator body. Face seals herein actively stretch and act as a “spacer” to help respirators better fit to narrower or shorter faces. The stretchability and resilience of face seals herein help maintain fit during a wearer’s facial and head movements. Face seals herein can be manufactured to fit any respirator style, shape or size - such as cup styles, vertical flat fold styles, horizontal flat fold styles, etc.

[0031] Some embodiments herein include fit features formed of material selected for sustainability and / or recyclability. Prior art respirator construction often utilizes polyurethane foam, which is crosslinked during formation to maintain a structure. Fit features herein, in some embodiments, are formed of a remeltable material.

[0032] 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 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 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 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

[0033] Table 1 lists the nonwoven webs used in making shirred media as described in US Provisional Patent Application 63 / 434365, Filed December 21, 2022 and Table 2 lists their initial pressure drop (dP) and penetration in NaCl and DOP tests.

[0034] The effective fiber diameter (EFD) can be estimated by using the measured pressure drop across a filter of known material according to the method set forth in C. N. Davies, Air Filtration (Academic, London, 1973).Table 1. Flat nonwoven webs used in making shirred media and respiratorsThe media webs in Table 1 were wrinkled as described in U.S. Provisional Patent Application 63 / 434365, filed on December 21, 2022. Table 2 lists the initial pressure drop and penetration of webs including the media listed in Table 1 andTable 2. Flat and wrinkled webs’ initial dP and penetration in NaCl tests

[0035] Elastic filaments 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.

[0036] 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.

[0037] 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-l, 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.

[0038] In one embodiment, the filaments 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

[0039] The elastic fibers or filaments are 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).

[0040] 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.

[0041] 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).

[0042] Suitable polyolefins include, but are not limited to, poly(ethylene), poly(propylene), poly(l- butene), poly-4-methyl-l -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) .

[0043] Suitable polyamides include, but are not limited to, typical nylon polymers such as poly(iminoadipoyliminohexamethylene), poly(iminoadipoyliminodecamethylene), and poly caprolactam. Suitable polyimides include, but are not limited to, poly(pyromellitimide).

[0044] Suitable poly(ether sulfones) include, but are not limited to, poly(diphenylether sulfone) and poly(diphenylsulfone-co-diphenylene oxide sulfone).

[0045] 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).

[0046] The fibers selected for the non-woven web depend upon the kind of particulate to be filtered. Particularly useful fibers include webs of meltblown fibers, such as those disclosed in Wente, Van A., "Superfine Thermoplastic Fibers", 48 Industrial Engineering Chemistry, 1342 et seq (1956). Webs of meltblown fibers provide especially good filtration layers when used in a persistent electrically charged form (see U.S. Pat. No. 4,215,682 to Kubik et al). Preferably, these meltblown fibers are microfibers having an effective diameter of at least 4, 6, 8 or even 10 micrometers and at most 12, 14, 16 or even 20 micrometers. Other particularly useful filtration fibers are electrically-charged-fibrillated-film- fibers as disclosed in U.S. Pat. No. RE 31,285 to Van Turnhout. Rosin wool fibrous webs and webs ofglass fibers are also useful, as are solution spun, or electrostatically sprayed fibers, especially in microfiber form.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] Particularly preferred change enhancing additives include hindered amine-based additives, triazine-based additives, and hindered phenol-based additives.

[0051] Specific examples of the hindered amine-based or triazine-based additives include (poly [[6- (1,1, 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-l,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-I50” from BASF; and 2,4,6-tris-(octadecylamino)triazine, also known as tristearyl melamine ("TSM").

[0052] 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]-l,l- dimethylethyl}-2,4,8,10-tetraoxaspiro-[5,5]undecane (Sumilizer-GA-80, manufactured by Sumitomo Chemical Co., Ltd.), and the like.

[0053] 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.

[0054] 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.).

[0055] 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 chargeenhancing 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 and Non-woven Porous Web with Sorbent

[0056] 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.

[0057] 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).

[0058] A wrinkled membrane may be wrinkled, for example, using the techniques described herein above with respect to FIGS. 1-2. In some embodiments, the elastic fibers or filaments are positioned between a membrane layer and one or more non-woven porous webs. However, it is expressly contemplated that, in some embodiments, the plurality of elastic 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.

[0059] Alternatively, or additional, non-woven porous web may comprise of a sorbent material. The sorbent particles may be disposed on the surface of non-woven web or throughout the depth of nonwoven web. One example of the sorbent material is activated carbon either untreated or chemically treated. 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.Method of Making

[0060] In one embodiment, the wrinkled filter media of the present application can be made by stretching a first series comprising a plurality of elastic fibers or filaments. The fibers or filaments are not generally bonded to one another (for example, the fibers or filaments of the present disclosure are not a scrim). The plurality of elastic fibers or filaments in the first series are held (for example using aspacer) such that each of the fibers or filaments is substantially parallel to one another and are spaced a given distance apart. Generally, the substantially parallel fibers or filaments should not touch the nearest neighbor fibers or filament in the working portion of the finished good. In one embodiment, the elastic fibers or filaments are held with a spacing of at least 2, 4, 5, or even 6 fibers or filaments per inch. In one embodiment, the elastic fibers filaments are held with a spacing of at most 8, 10, 12, 15, 20, or even 25 filaments per inch. Generally, the spacing of the fibers or filaments is selected to achieve the desired shirring of the non-woven web without causing a large change in pressure.

[0061] Shown in FIG. 3 is exemplary configuration of a first series of fibers 32, wherein the fibers are tied at either end and combs 35 and 37 are used at both ends to hold the fibers substantially parallel. The first series of fibers are placed between first non-woven porous fibrous web 34 and second nonwoven porous fibrous web 36. Either one or both of the non-woven porous webs 34 and 6 may contain sorbent particles. Nonwoven web 36 is placed below the stretched plurality of parallel fibers with the adhesive side contacting the fibers. The second adhesive -sprayed web 34 is placed above the stretched plurality of parallel fibers with the adhesive side contacting the fibers. An additional and optional nonwoven or woven porous web can be sprayed with adhesive and be placed onto the above laminate. Then, a cardboard roller compresses the laminate gently to remove any air pockets so that the nonwoven and / or woven webs were adhered together with the filaments positioned in between the two webs.

[0062] The manual hold of the stretched plurality of parallel fibers is then released, and the filaments are allowed to relax causing the laminated media (web-adhesive-fiber-adhesive-web-optional adhesive-web) to pucker. Additional details of how wrinkled media can be made can be found in US Provisional Patent Application 63 / 434365, filed December 21, specifically in paragraphs [0027-0037], which are incorporated herein by reference.

[0063] The fibers or filaments can be stretched to a desired length preferably before it reaches its elastic limit or yield point. The % stretch as used herein is defined as the difference between the length of the stretched fiber or filament and the length of the initial relaxed fiber or filament divided by the length of the initial relaxed fiber or filament converted to a percent. In one embodiment, the elastic fibers are stretched to between 50 and 250%. The filaments or fibers can be stretched more than 250% so long as the filaments do not go beyond the elastic limit to deformation or break during the manufacturing of the wrinkled media disclosed herein.

[0064] 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.

[0065] The first and second non-woven webs are bonded directly together such that the first nonwoven 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 nonwoven webs together. Such adhesives can include a pressure sensitive adhesive or a hot melt adhesive. Pressure sensitive adhesives are known in the art and are generally adhesives that can adhere based on room temperature conditions when pressure (e.g., finger pressure) is applied. Exemplary pressure sensitive adhesives include: a natural latex or synthetic polymer such as a (meth)acrylate. A commercially available pressure sensitive adhesive includes a spray adhesive available under the trade designation “3M Super 77 Multipurpose Adhesive” by 3M Company, Maplewood, MN, USA. Hot melt adhesives are those adhesives that are thermoplastic polymers which are heated above their softening point and when applied in their softened state to a surface, penetrate the surface and solidify ensuring cohesion. Exemplary hot melt adhesives include: Bostik HM-9041 available from Bostik inc., Wauwatosa, WI, and Tailored HM011BA available from Tailored Chemical Products Inc., Hickory, NC. In the embodiments of the present application when an adhesive is applied, the weight of adhesive used per unit area is less than the weight per unit area of the non-woven web. In one embodiment, the weight per unit area of the adhesive is less than 0.5, 0.4, 0.3, 0.2, or even 0.1 % of the weight per unit area of the non-woven porous fibrous webs in the article. Ideally, the adhesive should not interfere with the performance of the article and should be collapsible, meaning that the adhesive can maintain cohesiveness (or keep the two layers of non-woven webs bonded) upon the relaxing of the stretched fibers or filaments during manufacture. In one embodiment, the adhesive is at least 1, 2, 4, 5, or even 6 gsm (grams per square meter) in the wrinkled article. In one embodiment, the adhesive is at most 8, 10, 15, 20, 40, 60, 80 or even 100 gsm in the wrinkled article. In another embodiment, the first and second non-woven webs are welded directly together such that the first nonwoven 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.

[0066] 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.

[0067] In addition to the first and second non-woven webs, additional layers (e.g., athird layer) maybe added to the shirred article to provide additional functionality. The third non-woven or woven layer may be added before release of the tension on the filaments or fibers, such that the third layer is alsopuckered or shirred. In another embodiment, the third layer is added after release of the tension on the filaments or fibers, 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.

[0068] In another embodiment, in addition to the first series of elastic fibers or filaments, a second series of fibers or filaments can also be used, wherein the first and second series of elastic fibers or filaments are positioned non-parallel to each other (for example at least 45 degrees or at least 90 degrees apart). The shirred article is made as described above, except that both series of elastic fibers or filaments are placed between the two non-woven webs. When tension is released on both series of filaments, the resulting article has a more complex puckered pattern as shown in the Example Section of U.S. Provisional Patent Application 63 / 434365, filed on December 21, 2023.

[0069] In yet another embodiment, the series of elastic fibers or 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.

[0070] The articles of the present disclosure are resiliently extensible under tension, meaning that when the puckered article is pulled in the same direction as the length of the elastic fibers or filaments, the puckered article can elongate (or flatten out) and when the tension is released, the elongated article returns to its puckered form. In one embodiment, the puckered article is elastically extensible to at least 2 or even 3 times of its relaxed length. In some embodiments, the puckered article comprises at least one portion which is resiliently extensible under a first tension, wherein a second portion of the shirred filter media is under a second tension.

[0071] Because the articles of the present disclosure have a puckered (or shirred) appearance, the basis weight of the resulting article has a higher basis weight than the original flat or unwrinkled non-woven porous fibrous webs. In one embodiment, the shirred articles of the present disclosure have a basis weight of at least 20, 30, 40, 50, 100, or even 200 grams per square meter (gsm). In one embodiment, the shirred articles of the present disclosure have a basis weight of at most 200, 300, 400, 500, 600, 800, 1000, or even 1500 gsm.

[0072] The resulting shirred media is self-supporting meaning that an additional layer is not needed to provide support to the non-woven web / fiber or filament / non-woven web construction, optionally comprising an adhesive. Such articles can be used to filter out undesirable particles from the fluids, such as dust, molds, oily mist aerosol, cigarette smoke, pet dander, viruses, bacteria, etc.

[0073] 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).

[0074] 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, which are incorporated herein by reference.Test Methods

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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 TSI™ Model 8130 high-speed automated filter tester (available from TSI Inc., Shoreview, Minnesota) fortesting. Optionally, a larger size cup shaped respirator or a cup shaped respirator samples with perimeter extended out and with adequatemechanical resistance from deformation or collapse under air flow, may also be directly placed on top of the lower chuck of a TSI™ Model 8130 high-speed automated fdter 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.

[0079] 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:

[0080] 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.

[0081] For NaCl instantaneous testing at 85 liters / min (i.e. LPM) and using 0.075 pm 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.

[0082] The NaCl particles are forced through a media sample that has 11.4 cm in diameter or 102 cm2opening at a rate of 85 LPM.

[0083] The NaCl percent penetration is defined by the following formula:%Pen = (Concentration downstream / Concentration upstream) xlOO

[0084] The NaCl percent penetration and pressure drop are used to calculate a quality factor “QF” by the following formula:

[0085] A higher initial QF value indicates better initial filtration performance. Decreased QF values effectively correlate with decreased filtration performance.NaCl Loading Test:

[0086] 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 had an exposed area of 100.2 cm2with a nominal face velocity of 13.9 cm / sec for flat and wrinkled media sheets.

[0087] 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.

[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, or in reusable respirators, to form a layer or a portion of a pleat pack. These, and other examples, are discussed in greater depth in US Provisional Patent Application Ser. Nos. 63 / 496002 and 63 / 496003, both filed April 13, 2023.

[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. Fit features, e.g. features added to a respirator body to improve fit, may also have lower contact pressure with the same or higher level of filtration performance as the respirator media.

[0090] Fit features made of wrinkled media may act as a spacer to help a respirator fit better to a number of facial features - e.g. narrower or shorter faces. The stretch may also help to maintain fit of a respirator while a user changes facial expressions or move their head.

[0091] Fit features formed of wrinkled filter media also increase 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).

[0092] Fit features herein are illustrated with respect to a few example respiratory styles in the Figures herein. However, it is expressly contemplated that fit features described herein may be modified to fit any number of respirator styles, such as any of those described or illustrated in US Provisional Patent Application Ser. No. 63 / 496002, filed April 13, 2023, which is incorporated herein by reference in its entirety.

[0093] FIGS. 4-7 illustrate nose pads in accordance with embodiments herein. Nose pads, as described in FIGS. 4-7 herein, provide many advantages over traditional foam nose cushions. How a respirator fits to a wearer’s nose is a significant contributor to wearer comfort. Seal formation requires the noseforming features to conform to a user’s nasal bridge while maintaining rigid placement when in place. This is at odds with the requirement of comfort in order to improve compliance.

[0094] Many respirators include a formable nose clip (often metal) and a nose cushion. Traditionally a nose cushion is made of an open or closed cell foam that is cut and placed under or close to under the rigid nose clip. Metal nose clips will experience some “spring back” after the user shapes them for a nasal bridge. The compliant nose cushion helps to maintain a seal. Additionally, a nose cushion helps distribute the contact pressure exerted by the nose clip on the user’s face, which helps improve comfort. However, improvement is still needed. Previous designs have attempted to allow more cushioning by using multiple layers of material - e.g. folding. However, while multiple layers provide more cushioning when compressed, they do not expand as the respirator moves on a user’s face - e.g. talking, smiling, shaking their head.

[0095] Described herein is a nose pad that may be used with, or without, the traditional nose cushion. Nose pads described herein are formed of wrinkled media and, therefore, allow for active stretching and contracting as a wearer’s face moves, maintaining a good seal. Nose pads described herein are formed of wrinkled filtration media, such that the nose pad has the same or higher filtration performance, such that penetration of aerosols through it will not reduce the filter’s filtration efficacy rating. Nose pads herein may be formed from material that can be recycled, in some embodiments.

[0096] Traditional nose cushions are often made from polyurethane. There is a strong desire for the respirator market to move toward more sustainable, and recyclable, materials. Foams, such as polyurethane foams, are formed through crosslinking and, therefore, cannot be remelted, which is required for recyclability.

[0097] Traditional nose cushions are manufactured, generally, by supplying the nose cushion in a reel form. In contrast, nose pads herein may be formed using the standard respirator manufacturing process. The self-supporting nature of the wrinkled media web provides compliance to form a fit around the nasal bridge while the manufacturing process can produce splice-free continuous lengths.

[0098] FIGS. 4A-4D illustrate a cup-shaped respirator 400 having a nose pad 406. Respirator 400 includes a nose clip (not shown) as well as a traditional nose cushion 404. In the illustrated embodiment, nose pad 406 is sealed to respirator 400 along one edge, e.g. along a seal edge 408. Nose pad 406 may be welded, bonded, point-bonded, stitched or sealed in another suitable fashion to respirator body 400 in some embodiments. In some embodiments, nose pad 406 is adhered to the respirator body, for example using hot melt, pressure-sensitive or another suitable adhesive. Sealingnose pad 406 to respirator body 400 may allow for filtering of ambient air coming into the gap formed between the nose cushion 404 and nose pad 406. In some embodiments herein, nose pad 406 provides the same, or greater, filter efficiency as respirator body 400.

[0099] Nose pad 406 is formed of wrinkled media in accordance with embodiments herein, making it stretchable and fully resilient, as illustrated in the transition from FIG. 4B to 4D. When the applied force is removed, the nose pad 406 recovers to, or substantially recovers to the relaxed position of FIG. 4B. As used herein, substantially recovered means that the nose pad 406 recovers by at least 80%, or by at least 85%, or by at least 90%, or by at least 95%, or by at least 99%.

[0100] FIG. 4B illustrates an initial length 410 of a nose pad in a resting stretched state. It is expressly contemplated that length 410 may illustrate some stretch of the nose pad from a true resting state (e.g. a state of the wrinkled media forming nose pad with no compressing or stretching force applied) in some embodiments herein. As a wearer dons respirator 400, the wearer’s nose engages the nose pad 406 and, as illustrated by lengths 420 and 430, the nose pad 406 stretches. In some embodiments, the nose pad can stretch from an 8cm length in a resting state up to 10 cm length in a stretched state. The nose pad may stretch, along a longest diameter by at least 5%, in some embodiments. In some embodiments, the nose pad may stretch by at least 10% along a longest diameter. In some embodiments, the nose pad may stretch up to 25%, or by more than 50%, or even by at least 100% along a longest diameter. In some embodiments, a stretchability is limited by the interior perimeter length - e.g. a nose pad material may be capable of stretching up to 50% of a relaxed state length, but may only stretch by 25% before matching the internal perimeter of respirator body 400. When a user doffs respirator 400, the length returns to, or substantially to, length 410.

[0101] While respirator 400 is illustrated in FIGS. 4A-4D as having both a nose pad 406 and a nose cushion 404, it is expressly contemplated that embodiments herein may utilize the nose pad 406 without a nose cushion, such that the nose pad is primarily responsible for distributing contact pressure along the nasal bridge region.

[0102] Nose pad 406 is illustrated as having one edge 408 sealed to respirator body 402, however it is expressly contemplated that, in some embodiments, nose pad 406 is sealed alone additional edges - e.g. nose pad 406 may be sealed along at least 50% of a perimeter of the nose pad 406, or at least 60% of the perimeter of the nose pad 406, or at least 70% of the perimeter of the nose pad 406, or at least 80% of the perimeter of the nose pad 406, or at least 90% of the perimeter of the nose pad 406, or at least 95% of the nose pad 406, or along the full perimeter of the nose pad. Nose pad 406 may also take any suitable shape. For example, nose pad 406 may be rectangular, square, triangular round, etc. Nose pad 406 may also have irregular shapes cut into it for better conformance to the nose bridge. Some example shapes are illustrated, for example, in FIGS. 6A and 6C.

[0103] FIGS. 5A-5D illustrate a horizontal flat-fold respirator in accordance with embodiments herein. FIG. 5A illustrates a nose pad 504 welded to a respirator body 500 along a weld seam 502. Nose pad 504 is formed of a folded sheet of wrinkled media, for added cushion. However, it is expressly contemplated that some embodiments utilize a single sheet of wrinkled media to form a nose cushion. As described herein, wrinkled media can be made from nonwoven webs of varying thicknesses, so an amount of compliance of nose cushion 504 can be tailored.

[0104] As illustrated in FIG. 5B, nose cushion 520 has a nose-bridge length 522, and a width 524. Nose pad 520 is sealed to respirator 500. In some embodiments, a nose pad is sealed along a respirator body edge. In some embodiments, a nose pad is sealed along a nose pad edge along a seal line within the respirator body.

[0105] Illustrated in FIGS. 5A-5D is a nose pad sealed to a top panel of respirator 500. The presence of nose pad 502 on the top panel helps to reduce the flow and build-up of humid exhaled air, which can cause fogging of glasses.

[0106] The transition from FIG. 5C to 5D illustrates how the nose pad stretches under tension from a relaxed state 530 to a stretched state 540.

[0107] Nose pad 504 is illustrated as having one sealed edge 502, however it is expressly contemplated that, in some embodiments, nose pad 504 is sealed alone additional edges - e.g. nose pad 504 may be sealed along at least 50% of a perimeter of the nose pad 504, or at least 60% of the perimeter of the nose pad 504, or at least 70% of the perimeter of the nose pad 504, or at least 80% of the perimeter of the nose pad 504, or at least 90% of the perimeter of the nose pad 504, or at least 95% of the nose pad 504, or along the full perimeter of the nose pad.

[0108] FIGS. 6A-6D illustrate respirator bodies with nose pads in accordance with embodiments herein. FIG. 6A illustrates a cup-shape respirator 610 in accordance with embodiments herein having a nose pad 612 welded along the top seal line of respirator 620. Nose pad 612 has a notch in the middle that can be trimmed to various shapes and dimensions to help conformance in the nose region - a rounded triangle is illustrated. In the illustrated embodiment of FIGS. 6A-6D, nose pad 612 is formed of two layers of wrinkled media (as illustrated in FIG. 6C). The wrinkles of nose pad 612 are oriented generally vertically such that the nose pad stretches horizontally. In some embodiments, the wrinkled media selected for nose pad 612 can provide the same or higher filtration efficiency of ambient air than that of the respirator body.

[0109] FIG. 6A illustrates a nose foam 614 behind the nose pad 612. It is however expressly contemplated that embodiments herein include other configurations. For example, a respirator 610 may be formed with nose pad 612 formed of only one, or more than two, layers of media. Nose pad 612 may be formed of wrinkled media configured to stretch horizontally, vertically, or in bothdirections. Nose pad 612, in some embodiments, may be formed of media having substantially no stretch. Nose pad 612 is illustrated as having a concave shape in FIG. 6B, however it is expressly contemplated that other shapes are possible, for example convex shaped, irregularly shaped, or another suitable shape. Additionally, while a nose cushion 614 is illustrated in FIGS. 6A-6C, it is expressly contemplated that, in some embodiments herein, no nose cushion is present.

[0110] FIG. 6B illustrate a cup-shaped respirator having a nose pad 620 welded along an inner surface. In contrast to FIGS. 6A and 6C, nose pad 620 is a solid shape, having no convex or cut-out features.

[0111] FIG. 6C illustrates a cup-shaped respirator with a nose pad 630 that has an additional covering pad 632 welded along an inner surface. The covering pad 632 may or may not have the same shape and dimension as nose pad 630. Both nose pad 630 and covering pad 632 are formed of two layers of wrinkled media. Two layers of stretchable, flexible wrinkled material can provide added cushion and seal. While two layers of wrinkled media are illustrated, it is expressly contemplated that additional layers may be possible in some embodiments.

[0112] FIG. 6D illustrates a cup-shape respirator 640 having a nose pad 642 welded along an inner surface of the body of respirator 640. The nose pad 642 illustrated in FIG. 6D is made of wrinkled media and replaces a portion of the cup-shape respirator body 640 around nose region, allowing the nose region to be more flexible and stretchable than the rest of the respirator body. While a rounded nose pad shape 642 is illustrated, it is expressly contemplated that other shapes and sizes are possible in other embodiments. The media selected for nose pad 642 may have the same or better fdtration efficiency as the media used for respirator body 640. The nose pad 642, in some embodiments, can be combined with a nose clip to conform to a range of nose bridge sizes.

[0113] Another area of respirator discomfort in respirators concerns filtering face piece respirators (FFRs), which include a face seal. The presence of a face seal may result in a higher fit factor, which is required for many industries. Face seals are generally made of an impermeable substance - e.g. rubber or PVC, which are uncomfortable. Some FFRs have moisture permeable face seals, such as those scribed in PCT Publication WO 2014 / 110075, published July 7, 2014. However, such permeable face seals are generally cost prohibitive to manufacture.

[0114] FIGS. 7A-7H illustrate cup-shaped respirators with face seals in accordance with some embodiments herein. FIG. 7A illustrates an outer view 702 of a cup-shaped respirator 700. FIG. 7B illustrates an inner view 704 of cup-shaped respirator 700. The illustrated respirator 700 is an 8210Plus Respirator, available from 3M Company, located in St. Paul, Minnesota USA. However, while an 821 OPlus Respirator is illustrated, it is expressly contemplated that embodiments described herein may be suitable for other cup-shaped respirator designs. Additionally, it is also expressly contemplated thatother respirator designs, such as horizontal tri-fold, vertical fold, duck-billed, etc. may also benefit from face seals described herein.

[0115] FIGS. 7C-7D illustrate a respirator 710 having an added face seal layer 712. FIG. 7C illustrates a wrinkled media layer 712, sealed under tension to the periphery of the respirator opening, as illustrated by reference numeral 716. FIG. 7D illustrates layer 712 with an opening cut out to form a face seal 718 with inner perimeter 714. The face seal has an area extending from substantially the respirator body perimeter to inner perimeter 714. Face seal layer 712 stretches in the direction indicated by arrows 718. However, while horizontal stretching in direction 718 is illustrated, it is expressly contemplated that, in some embodiments, wrinkled media may be welded to a respirator body such that it is configured to stretch in a vertical direction.

[0116] The resulting respirator 714 has a smaller opening (perimeter 714) than the original 8210Plus Respirator. The face seal layer 712 illustrates only one example shape, but it is expressly contemplated that other shapes may be formed having a greater or smaller area, or a different perimeter shape. For example, while perimeter 714 is generally circular, it could also be ovular, or an irregular shape - e.g. with a notch removed for the wearer’s nose or chin. Additionally, a smaller or larger opening may be present in some embodiments.

[0117] FIG. 7E illustrates a respirator 720 having wrinkled media welded to its opening periphery to form a face seal 724, in accordance with embodiments herein. Face seal 724 has a notch 722 of material removed around the nose region, which may better conform to the nose of a wearer. The wrinkles of the wrinkled media forming face seal 724 are vertically oriented such that face seal 724 stretches in the direction indicated by arrows 726.

[0118] FIG. 7F illustrates a respirator 730 with wrinkled media welded to form a face seal 734 in accordance with embodiments herein. Face seal 734 also has a notch 732 removed from the otherwise substantially ring-shaped face seal. The wrinkles of the wrinkled media forming face seal 734 are horizontally oriented such that face seal 734 stretches in the direction indicated by arrows 736. However, while FIGS. 7E-7F illustrate either substantially exclusively vertical stretching or horizontal stretching. It is expressly contemplated that respirators in accordance with embodiments herein may have a face seal layer that stretches in both vertical and horizontal directions or have multiple face seal layers overlapped with different wrinkle orientations so that the multi-layer face seal can stretch in different orientations.

[0119] FIGS. 7G-7I illustrate different views of a respirator 740 formed from wrinkled media in accordance with embodiments herein. An 8210Plus shell, available from 3M Company located in St. Paul, MN, was used to form the cup-shape. However, it is expressly contemplated that other shell shapes could be used in accordance with embodiments herein. To form respirator 740, a filter layer ofwrinkled media 742 was stretched over the outer side or concave side of shell 746 while a face seal layer 744 was placed on the inner side of the cup shape under tension. The three layers (filter layer, shell and face seal) were then welded around the periphery. In embodiments herein, wrinkled media used as the filter layer covering the shell may be the same, or a different composition, as the wrinkled media used for the face seal layer.

[0120] Additionally, while only a single filter layer and a single face seal layer are described with respect to FIGS. 7G-7I, it is expressly contemplated that multiple layers of wrinkled media can be used to form either the face seal 744 and / or a filter layer 742. In this embodiment the wrinkles in face seal layer 744 are oriented in a substantially vertical direction such that the face seal can generally stretch in a horizontal direction. It is expressly contemplated, however, that respirators in accordance with embodiments herein may have a face seal layer or layers composed of wrinkled media configured to stretch in any of a vertical direction, a horizontal direction, a mixture of both horizontal and vertical directions, or in an angular direction. FIG. 7H illustrates an interior view of respirator 740, having a portion of the face seal layer 744 removed, leaving a substantially ring-shaped face seal 752. FIG. 71 illustrates a side view of respirator 740 showing both wrinkled media in both respirator body and face seal.

[0121] FIGS. 7C-7I illustrate examples where one or more layers of wrinkled media is used to form a face seal on a respirator. It is expressly contemplated that respirators in accordance with embodiments herein may have a face seal layer that has the same, or different, composition than a respirator body. For example, as illustrated in FIGS. 7C-7F, the respirator body is formed of nonwrinkled media while the face seal is formed of wrinkled media. However, it is also expressly contemplated that the respirator body may be formed with a first wrinkled media composition while the face seal layer is formed from a second wrinkled media composition such as respirator 740, illustrated in FIGs 7G-7I. For example, it may be desirable to have a face seal with a greater thickness to improve comfort, or a different composition with higher filtering capacity.

[0122] Forming a face seal from a face seal layer can be done, in some embodiments herein during manufacturing in the same step as forming the cup-shaped respirator (or other respiratory design). For example, ultrasonic welding can be used to attach the respirator filter layer to the cupshaped structure. A face seal may be added during the same step in embodiments where both the respirator filter layer and the face seal layer are both wrinkled media. Other attachment mechanisms may also be used, however, such as bonding, point-bonding, adhesive, stitching, etc.

[0123] While FIGS. 7A-7H describe forming a face seal in a face seal layer by cutting an aperture in the face seal layer expressly contemplated that other mechanisms may be used. For example, die-cutting, laser cutting, high energy light cutting, ultrasonic cutting. The face seal layersmay be sealed-through a die with a hole and sliced to form the face seal prior to respirator formation (e.g. sealing the fdter layer and face seal layer together).

[0124] FIGS. 7J-7K illustrate an embodiment herein with a harness fit feature. Many respiratory designs require a strap or harness to hold the respirator body to the face of a wearer. Some strap and harness designs can cause irritation over time due to tight straps or uncomfortable placement requirements to maintain a sufficient seal of the respirator body against a wearer’s face. Wrinkled media, however, may provide a sufficient retaining force with a reduced amount of irritation.

[0125] Illustrated in FIGS. 7J and 7K is a respirator 760 including a strap 762 formed of wrinkled media. In some embodiments, strap 762 is formed of a first portion of wrinkled media while a body of respirator 760 is formed of a second portion having the same, or different, composition of wrinkled media than the first portion. However, in some embodiments a single wrinkled media portion forms both strap portion 762 and respirator body 760, such that a unitary article is formed.

[0126] Strap 762 has a strap diameter 766 that is similar in size to a height 767 of a respirator body, in some embodiments. However, strap 762 may have any suitably sized strap diameter 766. A wider strap diameter 766 may spread out a retention force across a wider area of a user’s head, reducing irritation experienced by a wearer.

[0127] In some embodiments, an aperture or slit 764 is provided in harness 762, which is configured to accommodate a user’s ears, as wearers may find it more comfortable to have their ears uncovered by harness 762.

[0128] In accordance with embodiments herein, harness 762 is formed of wrinkled media having wrinkles oriented such that it is configured to stretch as indicated by arrow 768, such that a circumference of the respirator 760 can expand to accommodate wearers with different head circumferences.

[0129] While FIGS. 1-7 illustrate embodiments of fit features in a horizontal flat-fold model and a cup-shape model of respirator, it is expressly contemplated that other respirator models may benefit from fit features described herein. Nose pads and face seals formed from wrinkled media may be used in a number of disposable respirator models in order to provide improved breathability while maintaining high filter capacity. Some examples of respirator models that may benefit from wrinkled media include: tri-fold respirators (as illustrated in FIGS. 4A-4E of US Provisional Patent Application Ser. No. 63 / 496002, filed April 13, 2023, incorporated herein by reference), cup-shaped respirators (as illustrated in FIGS. 5A-5E as illustrated in US Provisional Patent Application Ser. No. 63 / 496002, filed April 13, 2023, incorporated herein by reference), vertical fold respirators (as illustrated in FIG. 6A of US Provisional Patent Application Ser. No. 63 / 496002, filed April 13, 2023, incorporated herein by reference), flat fold respirators, pleated respirators (as illustrated in FIG. 6B of US ProvisionalPatent Application Ser. No. 63 / 496002, filed April 13, 2023, incorporated herein by reference), and “duck-bill” respirators (as illustrated in FIG. 6C of US Provisional Patent Application Ser. No. 63 / 496002, filed April 13, 2023, incorporated herein by reference).

[0130] 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.

[0131] At block 810, respirator media is obtained. Wrinkled media 812 may be obtained for one or more layers or panels of a respirator, and serve as a respirator filter layer. Respirator media may include a face seal layer, in some embodiments. Respirator media may also include a nose pad layer, in some embodiments.

[0132] Flat media 814 may be obtained for one or more layers or panels. Other media 816 may also be used. For example, media with anti-fog properties may be obtained for a portion of the respirator. Alternatively, a shell layer may be obtained to use as a shell, for cup-shaped respirators, for example.

[0133] At block 820, one or more treatments are performed on one or more of the layers. For example, a cup shell may be shape-formed 822. One or more layers may be charged 824 to exhibit electret properties attracting and binding particulates and liquid droplets. Other treatments 828 may be performed.

[0134] A preform step 826, required for cup-shape respirators, can be a rate-limiting step in the manufacture of respirators as shell curvatures must be conformed to by the flat media in multiple directions, which may include cutting and welding media 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.

[0135] 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.

[0136] 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.

[0137] At block 830, a layer stack is formed. The layer stack may be composed of one or more fdter layers 832. Filter layers 832 may be wrinkled media and / or flat media layers. The layer stack 832 may include a face seal layer. The face seal layer may have a pre-formed inner diameter from a previous cutting step (not shown). The layer stack 832 may also include a nose pad layer. 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 or a flat 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.

[0138] 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 844 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.

[0139] In some embodiments, sealing a layer stack includes sealing a nose pad to a layer of respirator media. Sealing the nose pad may occur in the same sealing step as the respirator filter media layer(s), a subsequent step, or as a step prior to sealing 840.

[0140] 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.

[0141] A nose cushion 854 may also be added to increase comfort and improve seal. For example, custom nose cushions are described in PCT Publication WO 2022 / 235472, published on November 10, 2022, however other foam types and positions are expressly contemplated.

[0142] In addition to, or instead of, the nose cushion, a nose pad may be applied. As noted above, the nose cushion may be provided before, during or after a respirator body formation step.

[0143] 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 or extended from 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.

[0144] 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.

[0145] FIGS. 9A-9B illustrates a comparison of internal temperatures of respirators having different surface areas. FIG. 9A illustrates internal temperature measurements taken for three different respirator designs using the set up illustrated in FIG. 9B. Respirators 1-3 had different surface areas, with Respirator 1 having the smallest internal surface area, Respirator 2 having a more internal surface area than Respirator 1, and Respirator 3 having the largest internal surface area. As surface area goes up, air transfer speeds increase, allowing for the heat of a wearer’s exhaled breath to escape the respirator faster. Embodiments herein, therefore, are similarly expected to exhibit higher degrees of comfort with respect to temperature - e.g. wearers will be “cooler” wearing respirators having added fit features composed of wrinkled media, which increase an overall surface area for air to pass through.

[0146] 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 forstorage 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.

[0147] In some embodiments herein, a cup-style respirator is provided with one or more fit features. A cup-style respirator may include a respirator filter layer formed around or to a shell.

[0148] Other respirator styles with one or more fit features are also envisioned in accordance with embodiments herein, such as a vertical-fold style respirator, a pleated style respirator, such as that illustrated in US Pat. No. 8,640,704, FIGS. 1-4 and column 4, line 25 - column 5, line 29, incorporated herein by reference, a duck-bill style respirator, such as that described in U.S. Pat 5,322,061 to Brunson.

[0149] 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.

[0150] 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.

[0151] 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.

[0152] A disposable respirator includes a layer of wrinkled media. The wrinkled media includes: a first series of substantially parallel non-bonded elastic material 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 fit feature including wrinkled media.

[0153] The respirator may be implemented such that the fit feature includes a nose pad.

[0154] The respirator may be implemented such that the nose pad is sealed to a body of the disposable respirator, the body includes the layer of wrinkled media.

[0155] The respirator may be implemented such that at least 10% of a perimeter of the nose pad is sealed to the body.

[0156] The respirator may be implemented such that the perimeter includes a straight edge and the nose pad is sealed to the body along the edge.

[0157] The respirator may be implemented such that at least 25% of the perimeter is sealed to the body.

[0158] The respirator may be implemented such that at least 50% of the perimeter is sealed to the body.

[0159] The respirator may be implemented such that the layer of wrinkled media includes a first wrinkled media composition, and the nose pad includes a second wrinkled media composition different from the first wrinkled media composition.

[0160] The respirator may be implemented such that the nose pad includes a first wrinkled media with a first thickness, the layer of wrinkled media includes a second wrinkled media, and the first wrinkled media is thicker than the second wrinkled media.

[0161] The respirator may be implemented such that the nose pad and the layer of wrinkled media have the same wrinkled media composition.

[0162] The respirator may be implemented such that the nose pad includes a stretchable material such that the nose pad at least partially recovers from a stretched state to a relaxed state, the relaxed state includes the nose pad sealed to the respirator body, and the stretched state includes tension applied to the nose pad while sealed to the respirator body.

[0163] The respirator may be implemented such that the nose pad is configured to recover by at least 50%.

[0164] The respirator may be implemented such that the nose pad is configured to recover by at least 80%.

[0165] The respirator may be implemented such that the nose pad is configured to recover by at least 90%.

[0166] The respirator may be implemented such that the nose pad is configured to recover by at least 99%.

[0167] The respirator may be implemented such that the nose pad has a stretched length, in the stretched state, that is greater than 10% of a relaxed length, in a relaxed state.

[0168] The respirator may be implemented such that the stretched length is at least 15 % greater than the relaxed length.

[0169] The respirator may be implemented such that the stretched length is at least 30% greater than the relaxed length.

[0170] The respirator may be implemented such that the stretched length is at least 50% of the relaxed length.

[0171] The respirator may be implemented such that the stretched length is at least 100% of the relaxed length.

[0172] The respirator may be implemented such that the fit feature includes a face seal.

[0173] The respirator may be implemented such that the face seal includes an outer perimeter and an inner perimeter, and the outer perimeter is sealed to a respirator body.

[0174] The respirator may be implemented such that the outer perimeter is sealed to the layer of wrinkled media.

[0175] The respirator may be implemented such that the outer perimeter is sealed to a shell layer.

[0176] The respirator may be implemented such that the face seal stretches to confirm to the 3D shape of the human face.

[0177] The respirator may be implemented such that the disposable respirator has an interior surface, and the face seal is configured to stretch to the point that it contacts the inner surface of the respirator along an inner perimeter of the face seal.

[0178] The respirator may be implemented such that sealing includes welding, bonding, point bonding or stitching.

[0179] The respirator may be implemented such that the disposable respirator is a horizontal flat-fold style respirator.

[0180] The respirator may be implemented such that the disposable respirator is a cup-shape style respirator, and the cup-shape respirator includes a shell.

[0181] The respirator may be implemented such that the disposable respirator is a vertical-fold style respirator.

[0182] The respirator may be implemented such that the disposable respirator is a pleated style respirator.

[0183] The respirator may be implemented such that the disposable respirator is a duck bill style respirator.

[0184] The respirator may include: a nose clip, a nose foam , a valve, or a harness.

[0185] The respirator may include a strap, and the strap, in combination with the layer of wrinkled media, forms a unitary wrinkled media article.

[0186] The respirator may be implemented such that the strap includes an aperture configured to receive an ear of a wearer.

[0187] The respirator may be implemented such that one of the first and second nonwoven layers includes a membrane.

[0188] The respirator may be implemented such that one of the first and second nonwoven layers includes a fibrous nonwoven material.

[0189] The respirator may be implemented such that the elastic material includes a filament.

[0190] The respirator may be implemented such that the elastic material includes a fiber.

[0191] The respirator may be implemented such that the elastic material includes a scrim.

[0192] A disposable respirator includes a respirator body including a respirator filter layer, a nose clip coupled to the respirator body, the nose clip including a formable material, a nose pad coupled to the respirator body, the nose pad including wrinkled media, the nose pad is configured to stretch from a relaxed state, with a relaxed length, to a stretched state, with a stretched length, when the respirator is worn by a wearer, and a strap configured to, when the disposable respirator is worn, pull the respirator body toward a face of the wearer.

[0193] The disposable respirator may be implemented such that the wrinkled media includes: a first series of substantially parallel non-bonded elastic filaments between a first and a second nonwoven porous web, and the first non-woven porous web is directly bonded to the second non-woven porous web.

[0194] The disposable respirator may be implemented such that the wrinkled media is a first wrinkled media, and the respirator filter layer includes a second wrinkled media.

[0195] The disposable respirator may be implemented such that the first wrinkled media includes a different composition than the second wrinkled media.

[0196] The disposable respirator may be implemented such that the respirator filter layer includes flat media.

[0197] The disposable respirator may be implemented such that the flat media has a flat media stretched length at a flat media stretched state that is less than 10% greater than a flat media relaxed length at a flat media relaxed state.

[0198] The disposable respirator may be implemented such that the nose pad is configured to at least partially recover from a stretched state to a relaxed state, the relaxed state includes the nose pad sealed to the respirator body, and the stretched state includes tension applied to the nose pad while sealed to the respirator body.

[0199] The respirator may be implemented such that the nose pad is configured to recover by at least 50%.

[0200] The respirator may be implemented such that the nose pad is configured to recover by at least 80%.

[0201] The respirator may be implemented such that the nose pad is configured to recover by at least 90%.

[0202] The respirator may be implemented such that the nose pad is configured to recover by at least 99%.

[0203] The respirator may be implemented such that the nose pad is sealed to the respirator body.

[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 nose pad is sealed along at least 30% of a nose pad perimeter.

[0206] The respirator may be implemented such that the nose pad is sealed along at least 50% of a nose pad perimeter.

[0207] The respirator may be implemented such that the nose pad is sealed along at least 90% of a nose pad perimeter.

[0208] The respirator may be implemented such that the nose pad is sealed to an interior surface of the respirator body.

[0209] The respirator may be implemented such that the nose pad is sealed to an exterior surface of the respirator body.

[0210] The respirator may include a nose foam coupled to an inner surface of the respirator body.

[0211] The respirator may include a face seal coupled to an inner surface of the respirator body.

[0212] The respirator may be implemented such that the face seal includes a third wrinkled media composition.

[0213] The respirator may be implemented such that the strap, in combination with the second wrinkled media, forms a unitary wrinkled media article.

[0214] The respirator may be implemented such that the formable material includes a metal.

[0215] The respirator may be implemented such that the disposable respirator is a horizontal flat-fold style respirator.

[0216] The respirator may be implemented such that the disposable respirator is a cup-shape style respirator, and the cup-shape respirator includes a shell.

[0217] The respirator may be implemented such that the disposable respirator is a vertical-fold style respirator.

[0218] The respirator may be implemented such that the disposable respirator is a pleated style respirator.

[0219] The respirator may be implemented such that the disposable respirator is a duck bill style respirator.

[0220] A disposable respirator includes a respirator body including a respirator filter layer, a nose clip coupled to the respirator body, the nose clip including a formable material, a face seal coupled to an interior of the respirator body, the face seal including wrinkled media, a strap configured to, when the disposable respirator is worn, pull the respirator body toward a face of the wearer.

[0221] The disposable respirator may include a first series of substantially parallel non-bonded elastic filaments between a first and a second non-woven porous web, and the first non-woven porous web is directly bonded to the second non-woven porous web.

[0222] The disposable respirator may be implemented such that the wrinkled media is a first wrinkled media, and the respirator filter layer includes a second wrinkled media.

[0223] The disposable respirator may be implemented such that the first wrinkled media includes a different composition than the second wrinkled media.

[0224] The disposable respirator may be implemented such that the respirator filter layer includes flat media.

[0225] The disposable respirator may be implemented such that the flat media has a flat media stretched length at a flat media stretched state that is less than 10% greater than a flat media relaxed length at a flat media relaxed state.

[0226] The disposable respirator may be implemented such that the face seal includes an outer perimeter and an inner perimeter, and the outer perimeter is sealed to a respirator body.

[0227] The disposable respirator may be implemented such that the outer perimeter is sealed to the layer of wrinkled media.

[0228] The disposable respirator may be implemented such that the outer perimeter is sealed to a shell layer.

[0229] The disposable respirator may be implemented such that the face seal stretches to confirm to the 3D shape of the human face.

[0230] The disposable respirator may be implemented such that the respirator includes an inner surface configured to receive an exhalation of a wearer, the face seal includes an inner perimeter, and the face seal is configured to stretch such that the inner perimeter contacts the inner surface of the respirator.

[0231] The disposable respirator may be implemented such that sealing includes welding, bonding, point bonding or stitching.

[0232] The disposable respirator may be implemented such that the disposable respirator is a horizontal flat-fold style respirator.

[0233] The disposable respirator may be implemented such that the disposable respirator is a cup-shape style respirator, and the cup-shape respirator includes a shell.

[0234] The disposable respirator may be implemented such that the disposable respirator is a vertical-fold style respirator.

[0235] The disposable respirator may be implemented such that the disposable respirator is a pleated style respirator.

[0236] The disposable respirator may be implemented such that the disposable respirator is a duck bill style respirator.

[0237] The disposable respirator may include: a nose clip, a nose foam , a valve, or a harness.

[0238] The disposable respirator may include a strap, and the strap, in combination with the layer of wrinkled media, forms a unitary wrinkled media article.

[0239] The disposable respirator may be implemented such that one of the first and second nonwoven layers includes a membrane.

[0240] The disposable respirator may be implemented such that one of the first and second nonwoven layers includes a fibrous nonwoven material.

[0241] A method of making a respirator that includes obtaining a fit feature, the fit feature including a layer of wrinkled media. At least one portion of the wrinkled media is resiliently extensible under tension. The method also includes forming a respirator body, the respirator body includes a stack of media layers, and sealing the stack of media layers, such that the respirator body is coupled to the layer of wrinkled media.

[0242] The method may be implemented such that the fit feature includes a nose pad.

[0243] The method may be implemented such that sealing the stack of media layers includes sealing the layer of wrinkled media to an interior surface of the respirator body.

[0244] The method may be implemented such that sealing the stack of media layers includes sealing the layer of wrinkled media to an exterior surface of the respirator body.

[0245] The method may be implemented such that sealing the stack of media layers includes sealing a perimeter of the layer of wrinkled media to the respirator body.

[0246] The method may be implemented such that sealing includes sealing at least 30% of the layer of wrinkled media to the respirator body.

[0247] The method may be implemented such that at least 50% of a perimeter of the nose pad is sealed to the body.

[0248] The method may be implemented such that the fit feature includes a face seal.

[0249] The method may be implemented such that the face seal includes a stretchable material such that the face seal at least partially recovers from a stretched state to a relaxed state, the relaxedstate includes the face seal attached to the respirator body, and the stretched state includes tension applied to the face seal while attached to the respirator body.

[0250] The method may be implemented such that the face seal is configured to recover by at least 50%.

[0251] The method may be implemented such that the face seal is configured to recover by at least 80%.

[0252] The method may be implemented such that the face seal is configured to recover by at least 90%.

[0253] The method may be implemented such that the face seal is configured to recover by at least 99%.

[0254] The method may be implemented such that the formed respirator includes an inner surface configured to receive an exhaled breath of a user, the face seal has an inner perimeter, and the face seal is configured to stretch such that the inner perimeter contacts the inner surface of the formed respirator.

[0255] The method may be implemented such that sealing the stack of media layers includes sealing the layer of wrinkled media to an interior surface of the respirator body.

[0256] The method may be implemented such that sealing the stack of media layers includes sealing the layer of wrinkled media to an exterior surface of the respirator body.

[0257] The method may be implemented such that sealing the stack of media layers includes sealing a perimeter of the layer of wrinkled media to the respirator body.

[0258] The method may be implemented such that sealing includes sealing at least 30% of the layer of wrinkled media to the respirator body.

[0259] The respirator may be implemented such that at least 50% of a perimeter of the nose pad is sealed to the body.

[0260] The method may include: preforming the stack of media layers, wherein preforming forms the stack of media layers into a cup-shape.

[0261] The method may be implemented such that one layer of the stack of media layers includes a shell layer.

[0262] The method may 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.

[0263] The method may be implemented such that sealing includes welding, point-welding, bonding, or point-bonding, or forming a seam.

[0264] The method may be implemented such that the stack of media layers further includes one of a cover web, a sorbent layer, a filter layer, or a shell layer.

[0265] The method may be implemented such that the respirator is a horizontal tri-fold respirator.

[0266] The method may be implemented such that the respirator is a vertical fold respirator.

[0267] The method may be implemented such that the respirator is a cup-shape respirator.

[0268] The method may be implemented such that the respirator is a pleated respirator.

[0269] The method may be implemented such that the respirator is a duck-bill respirator.

[0270] The method may be implemented such that the layer of wrinkled media includes: a first series of substantially parallel non-bonded elastic filaments between a first and a second non-woven porous web, and the first non-woven porous web is directly bonded to the second non-woven porous web.

[0271] The method may be implemented such that the layer of wrinkled media is a first layer of wrinkled media, and the stack of media layers includes a second layer of wrinkled media.

[0272] The respirator may be implemented such that the first layer and the second layer have the same composition.

[0273] The respirator may be implemented such that the first layer has a different composition than the second layer.

[0274] The respirator may be implemented such that the first layer has a different thickness than the second layer.ExamplesFit Test PanelFace Fit Performance of Comparative Example (CE) 1 and Examples (EX) 1 through 3

[0275] A face fit test was employed to determine the amount of leakage between a respirator user's face and the seal structure(s) of a tight-fitting respirator. The amount of face seal leakage between a respirator and a user's face can be quantified by measuring the concentration of a test aerosol (e.g. NaCl particles suspended in air) on the inside and outside of a respirator. A useful face fit test has been developed, which selectively detects particles of 60 nanometers (nm) or smaller. See U.S. Pat. No. 6,125,845 to Halvorson et al. A commercially available instrument suitable for use in the face fit test is the TSI PortaCount® Pro+ (TSI Inc., Shoreview, Minnesota). Another suitable instrument is the TSI PortaCount® Plus with N95-Companion™ (TSI me).

[0276] Eleven samples for each of CE 1 and EX 1 through 3 were prepared for face fit testing on human subjects. CE 1 was a cup-shaped respirator available under the trade designation “3M Disposable Respirator 8210plus” available from 3M CO., Maplewood, MN, USA, as shown in FIGs. 7A and 7B. EX 1 samples were made with a shaped wrinkled media welded to CE 1 respirators to forma face seal. The face seal material was W4-150 media as designated in Table 2. The wrinkles in face seal media were oriented in parallel to nose-to-chin direction on respirators. EX 2 samples were made with the same media welded to CE 1 respirators as a face seal, with wrinkles in face seal media oriented perpendicular to nose-to-chin direction on respirators. EX 3 samples were made with two layers of the same W4-150 media welded to nose area on CE 1 respirator to form a nose pad. FIGs. 7E, 7F, 6A exhibits configurations of EX 1, EX 2 and EX 3 respectively.

[0277] A sample probe fixture (TSI Inc) was attached to each sample so that the aerosol concentration inside the sample could be determined during the face fit test. Eleven human subjects that had a range of facial lengths and facial widths were selected. The measured facial length and width correspond to menton-sellion length and bizygomatic breadth, respectively, as described by Z. Zhuang et al., New Respirator Fit Test Panels Representing the Current US. Civilian Workforce, Journal of Occupational and Environmental Medicine, 2007, 4:647-659. All subjects were tested using each of CE 1 and EX 1 through 3.

[0278] Face fit tests were conducted in a test chamber that was approximately 2.5 m high by 2 m wide by 1.5 m deep and that was ventilated with filtered air. A NaCl aerosol where the particles had an approximate count median diameter of 50 nm was generated using a TSI Model 8026 Particle Generator ((TSI Inc., Shoreview, Minnesota)) containing 2% NaCl (weight to volume) in distilled water. The atomizer was adjusted so that a reading of between 500 particles / cc and 1,500 particles particles / cc could be obtained with a fit test system composed of a PortaCount® Plus with N95- CompanionTM in the "Count mode".

[0279] For each fit test, the subjects donned the respirator sample, entered the chamber and attached the respirator to the fit test system via the sample probe and a hose. The subject was then asked to perform eight exercises that are defined in US Code of Federal Regulations 29 CFR 1910. 134, Appendix A, Part I. A.14. During these exercises, particle concentration data was collected from the fit test system using a microcomputer. The data can be obtained without a microcomputer by running the fit test system in "Count mode" and recording the data manually from the fit test system readout. The specific exercises, their duration, and the data collection scheme are shown below in Table 3, the Face Fit Test Exercise and Data Collection Table. The start and end times are measured in seconds (s) after the exercise begins.Table 3

[0280] A fit factor was calculated for each exercise except Grimace. Fit Factor is equal to the chamber aerosol concentration divided by the internal respirator aerosol concentration. For each exercise, the chamber aerosol concentration used was the mean of the chamber concentrations measured immediately before and after the concentration inside the respirator. An average fit factor for each subject with each sample respirator was obtained by calculating the harmonic mean of the seven fit factors for the 1stNormal Breathing, Deep Breathing, Up and Down Head Movements, Side to Side Head Movement, Rainbow Message Reading, Bending at Waist, and 2ndNormal Breathing exercises. The harmonic mean can be obtained by computing the reciprocal of the arithmetic mean of the reciprocals of the individual exercise fit factors. The results of the face fit tests conducted using samples of CE 1 and EX 1 through 3 are shown below in Table 4:Table 4Face Fit Test Performance

[0281] The fit factor for nine of the eleven subjects was significantly higher for the inventiveExample 1 through 3 when compared to Comparative Sample CE 1, showing a significant reduction in face seal leakage. In only two subjects (Subjects 8 and 9) were the fit factors found to be lower in Example EX 1 than Comparative Example CE 1. In only one subject (Subject 9) was the fit factors found to be lower in Example EX 2 than Comparative Example CE 1.

[0282] This invention may take on various modifications and alterations without departing from its spirit and scope. Accordingly, this invention is not limited to the above described but is to be controlled by the limitations set forth in the following claims and any equivalents thereof.

[0283] This invention also may be suitably practiced in the absence of any element not specifically disclosed herein.

[0284] All patents and patent applications cited above, including those in the Background section, are incorporated by reference into this document in total. To the extent there is a conflict or discrepancy between the disclosure in such incorporated document and the above specification, the above specification will control.

Claims

What is claimed is:

1. A disposable respirator comprising: a layer of wrinkled media, wherein the wrinkled media comprises: a first series of substantially parallel non-bonded elastic material between a first and a second non-woven porous web; and wherein the first non-woven porous web is directly bonded to the second non-woven porous web; and wherein at least one portion of the wrinkled media is resiliently extensible under tension; and a fit feature comprising wrinkled media.

2. The respirator of claim 1, wherein the fit feature comprises a nose pad.

3. The respirator of claim 2, wherein the nose pad is sealed to a body of the disposable respirator, wherein the body comprises the layer of wrinkled media.

4. The respirator of claim 3, wherein at least 10% of a perimeter of the nose pad is sealed to the body.

5. The respirator of claim 3, wherein the perimeter comprises a straight edge and wherein the nose pad is sealed to the body along the edge.

6. The respirator of claim 2, wherein the layer of wrinkled media comprises a first wrinkled media composition, and wherein the nose pad comprises a second wrinkled media composition different from the first wrinkled media composition.

7. The respirator of claim 2, wherein the nose pad comprises a first wrinkled media with a first thickness, the layer of wrinkled media comprises a second wrinkled media, and wherein the first wrinkled media is thicker than the second wrinkled media.

8. The respirator of claim 2, wherein the nose pad and the layer of wrinkled media have the same wrinkled media composition.

9. The respirator of claim 3, wherein the nose pad comprises a stretchable material such that the nose pad at least partially recovers from a stretched state to a relaxed state, wherein the relaxed state comprises the nose pad sealed to the respirator body, and wherein the stretched state comprises tension applied to the nose pad while sealed to the respirator body.

10. The respirator of claim 9, wherein the nose pad is configured to recover by at least 50%.11 . The respirator of claim 9, wherein the nose pad has a stretched length, in the stretched state, that is greater than 10% of a relaxed length, in a relaxed state.

12. The respirator of any of claims 1-11, wherein the fit feature comprises a face seal.

13. The respirator of claim 12, wherein the face seal comprises an outer perimeter and an inner perimeter, and wherein the outer perimeter is sealed to a respirator body.

14. The respirator of claim 12, wherein the disposable respirator has an interior surface, and wherein the face seal is configured to stretch to the point that it contacts the inner surface of the respirator along an inner perimeter of the face seal.

15. The respirator of any of claims 1-14, wherein the disposable respirator is a horizontal flat-fold style respirator, a cup-shape style respirator, a vertical-fold style respirator, a pleated style respirator, or a duck-bill style respirator.

16. The respirator of any of claims 1-15, and further comprising: a nose clip, a nose foam , a valve, or a harness.

17. The respirator any of claims 1-15, and also comprising a strap, and wherein the strap, in combination with the layer of wrinkled media, forms a unitary wrinkled media article.

18. A disposable respirator comprising: a respirator body comprising a respirator fdter layer; a nose clip coupled to the respirator body, the nose clip comprising a formable material; a face seal coupled to an interior of the respirator body, the face seal comprising wrinkled media; a strap configured to, when the disposable respirator is worn, pull the respirator body toward a face of the wearer.

19. The disposable respirator of claim 18, 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; and wherein the first non-woven porous web is directly bonded to the second non-woven porous web.

20. The disposable respirator of claim 18 or 19, wherein the wrinkled media is a first wrinkled media, and wherein the respirator filter layer comprises a second wrinkled media.21 . The disposable respirator of claim 20, wherein the first wrinkled media comprises a different composition than the second wrinkled media.

22. The disposable respirator of any of claims 18-21, wherein the respirator filter layer comprises flat media.

23. The disposable respirator of any of claims 18-22, wherein the face seal comprises an outer perimeter and an inner perimeter, and wherein the outer perimeter is sealed to a respirator body.

24. The disposable respirator of claim 23, wherein the outer perimeter is sealed to the layer of wrinkled media.

25. The disposable respirator of claim 24, wherein the outer perimeter is sealed to a shell layer.

26. The disposable respirator of claim 25, wherein the respirator comprises an inner surface configured to receive an exhalation of a wearer, wherein the face seal comprises an inner perimeter, and wherein the face seal is configured to stretch such that the inner perimeter contacts the inner surface of the respirator.

27. The disposable respirator of any of claims 18-26, wherein the disposable respirator is a horizontal flat-fold style respirator, a cup-shape style respirator, a vertical-fold style respirator, a pleated style respirator or a duck bill style respirator.

28. A method of making a respirator, the method comprising: obtaining a fit feature, the fit feature comprising a layer of wrinkled media, wherein at least one portion of the wrinkled media is resiliently extensible under tension; forming a respirator body, wherein the respirator body comprises a stack of media layers; sealing the stack of media layers, such that the respirator body is coupled to the layer of wrinkled media.

29. The method of claim 28, wherein the fit feature comprises a nose pad.

30. The method of claim 29, wherein sealing the stack of media layers comprises sealing the layer of wrinkled media to an interior surface of the respirator body.31 . The method of claim 29, wherein sealing the stack of media layers comprises sealing the layer of wrinkled media to an exterior surface of the respirator body.

32. The method of claim 30, wherein sealing the stack of media layers comprises sealing a perimeter of the layer of wrinkled media to the respirator body.

33. The method of any of claims 28-32, wherein the fit feature comprises a face seal.

34. The method of claim 33, wherein the face seal comprises a stretchable material such that the face seal at least partially recovers from a stretched state to a relaxed state, wherein the relaxed state comprises the face seal attached to the respirator body, and wherein the stretched state comprises tension applied to the face seal while attached to the respirator body.

35. The method of claim 33, wherein sealing the stack of media layers comprises sealing the layer of wrinkled media to an interior surface of the respirator body.

36. The method of claim 33, wherein sealing the stack of media layers comprises sealing the layer of wrinkled media to an exterior surface of the respirator body.

37. The method of claim 33, wherein sealing the stack of media layers comprises sealing a perimeter of the layer of wrinkled media to the respirator body.

38. The method of claim 37, wherein sealing comprises sealing at least 30% of the layer of wrinkled media to the respirator body.

39. The method of any of claims 28-38, and further comprising: preforming the stack of media layers, wherein preforming forms the stack of media layers into a cup-shape.

40. The method of any of claims 28-38, 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 web; and wherein the first non-woven porous web is directly bonded to the second non-woven porous web.

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