Respirators, respirator materials, and methods of making the same

Abstract

A disposable flat-fold respirator is presented that includes a mask body that includes a plurality of panels that are foldable toward one another and unfoldable into an open configuration. The mask body includes a single layer of electrically charged filtration material. The plurality of panels includes an upper panel, a lower panel, and a middle panel. The middle panel is connected to the upper panel and the lower panel. The respirator filters at least 95% of airborne particles having a mass median aerodynamic diameter of 0.3 µm. A harness is secured to the mask body.

Description

Background Technology

[0001] Maintenance-free respirators (sometimes referred to as “filtering masks” or “filtering respirators”) are typically worn over a person’s breathing passage to prevent impurities or contaminants from being inhaled. Maintenance-free respirators typically consist of a mask body and a strap, and have filter material incorporated into the mask body itself (instead of having an attachable filter cartridge or insertable molded filter element (see, for example, U.S. Patent 4,790,306 to Braun)) to remove contaminants from ambient air.

[0002] To ensure that contaminants do not inadvertently enter the mask without passing through the filter media, maintenance-free respirators are designed to fit snugly against the wearer's face. Most conventional maintenance-free respirators conform to the contours of the face above the cheeks and chin. However, the complex contour changes in the nasal region make achieving a snug fit more challenging. A failure to achieve a snug fit can allow air to enter and exit the respirator without passing through the filter media. In this case, contaminants may enter the wearer's respiratory tract, and other people or objects may be exposed to the contaminants exhaled by the wearer. Additionally, the wearer's glasses may fog up, which obviously worsens visibility for the wearer and creates further unsafe conditions for the user and others. Summary of the Invention

[0003] A disposable, foldable respirator is presented, comprising a mask body including multiple panels that can be folded toward each other and unfolded into an open configuration. The mask body includes a single layer of electrically charged filtering material. The multiple panels include an upper panel, a lower panel, and a middle panel. The middle panel is connected to the upper and lower panels. The respirator filters at least 95% of airborne particles with a median aerodynamic diameter of 0.3 µm. Straps are attached to the mask body.

[0004] The foregoing description of this invention is not intended to describe every disclosed embodiment or implementation. The following description provides more specific examples of exemplary embodiments. Therefore, it should be understood that the following description should not be construed as an undue limitation on the scope of this disclosure. Attached Figure Description

[0005] Figures 1A to 1D A view of a respirator according to an embodiment of this document is shown.

[0006] Figure 2 The construction of a conventional respirator is illustrated.

[0007] Figure 3 A method for constructing a respirator according to the embodiment described herein is illustrated. Detailed Implementation

[0008] As used in this document, the following terms are defined as follows:

[0009] The term "approximately" is used to indicate that the specified value is approximate and may include variations within a range of at least ±10% of the stated value. This term allows for minor deviations from precise values, thus acknowledging that such variations do not significantly affect the overall function or performance of the product. For example, "approximately 60 gsm" could cover values ​​from 54 gsm to 66 gsm, providing flexibility while ensuring the product remains within acceptable performance parameters.

[0010] "Middle panel" refers to the panel located between the top panel and the bottom panel;

[0011] "Clean air" refers to a certain volume of ambient air that has been filtered to remove pollutants.

[0012] "Contaminants" refers to particulate matter (including dust, mist and smoke) and / or other substances that are not broadly considered particulate matter (such as organic vapors) but may be suspended in the air (including exhaled air);

[0013] "External gas space" refers to the ambient atmospheric gas space that exhaled air enters after passing through and leaving the mask body and / or exhalation valve;

[0014] "Filter" or "filter layer" means one or more layers of material suitable for the primary purpose of removing contaminants (such as particles) from the airflow passing through it;

[0015] "Filter media" refers to a breathable structure designed to remove pollutants from the air that passes through it;

[0016] "Flat-fold" means that the respirator has at least one dividing line, and the respirator typically folds or bends around the at least one dividing line in response to simple manual pressure.

[0017] "One piece" means that it is part of the entire panel or mask body and not a separate piece attached to it;

[0018] "Band" refers to a structure or combination of components that helps to support the main body of the mask on the wearer's face;

[0019] "Internal gas space" refers to the space between the mask body and the person's face;

[0020] "Boundary line" means fold, seam, weld line, joint line, stitch line, hinge line, and / or any combination thereof;

[0021] "Lower panel" refers to the panel that extends below or contacts the wearer's chin when the respirator is worn.

[0022] The “mask body” refers to a breathable structure that can at least fit over a person’s nose and mouth and help to define an internal gas space that is separated from the external gas space.

[0023] "Molding" means to mold a component (e.g., a molded layer) into a predefined form after exposure to heat and / or pressure;

[0024] "Nose clip" refers to a mechanical device (not a nose foam) that is designed to be used on the mask body to improve the seal at least around the wearer's nose;

[0025] "Nose foam" refers to a foam material that is suitable for placement inside the mask body to improve the fit over the nose and / or wearer comfort when the respirator is worn.

[0026] "Nasal area" refers to the part of the respirator that sits on the nose when the respirator is worn.

[0027] "Panel" refers to a three-dimensional component or part that is much larger in the first and second dimensions than in the third dimension;

[0028] "Periphery" refers to the outer edge of the main body of the mask, which will be positioned close to the wearer's face when the respirator is worn.

[0029] "Polymer" refers to a substance that contains repeating chemical units arranged in a regular or irregular manner;

[0030] "Polymer" and "plastic" each refer to materials that primarily consist of one or more polymers and may also contain other components. "Polymer" refers to materials that contain repeating chemical units arranged in a regular or irregular manner.

[0031] “Respirator” means a device worn by a person to filter air before it enters the wearer’s respiratory system; specifically, the respirator described herein has a filtration efficiency that meets one or more international standards for filtration efficiency (such as N95, N99, P95, P99, KN95 or other applicable standards from U.S. agencies or other jurisdictions).

[0032] "Upper panel" refers to the panel that extends above the nasal area and below the wearer's eyes when the respirator is worn; and

[0033] "Upper section" refers to the peripheral area extending above the nose and below the wearer's eyes when the respirator is worn.

[0034] Figures 1A to 1D A view of a respirator according to an embodiment of this document is shown. Figures 1A to 1DAn embodiment of a respirator is illustrated as a folding respirator. The folding respirator is not entirely formed in its intended cup-shaped configuration for wear over the nose and mouth. Instead, the mask body unfolds from a folded state into a cup-shaped or open configuration. However, it is explicitly envisioned that the embodiments described herein can be applied to other respirator designs. For example, the filter media described herein can be used to form horizontally folding respirators, vertically folding respirators, cup-shaped respirators, duckbill-shaped respirators, and / or pleated media respirators.

[0035] The illustrated flat-fold respirator 10 provides a source of clean air for breathing to the wearer. The respirator 10 includes a mask body 12 and a strap 14, wherein the mask body 12 has multiple panels, including an upper panel 16, a middle panel 18, and a lower panel 20. The mask body 12 has a periphery including a peripheral periphery 22, particularly a face-contact periphery, which is positioned next to the wearer's face when the mask is worn. A grippable flap extends from the peripheral periphery, particularly the peripheral periphery. In the illustrated embodiment, the flap extends centrally from the lower panel 20. To open the mask body... Figures 1C to 1D As shown in the ready-to-use configuration, the user pulls the tab 21 in a direction away from the adjacent or opposite panel.

[0036] Figures 1C to 1D The mask body is shown in its open configuration, ready to be placed on a person's face. When the person is not wearing the respirator 10, the respirator can be folded flat for use as... Figures 1A to 1B Store as shown. Figures 1A to 1D As illustrated, the middle panel 18 is separated from the upper panel 16 and the lower panel 20 by a first dividing line 24 and a second dividing line 26. The upper panel 16 and the lower panel 20 are separated when the mask is folded flat for storage. Figures 1A to 1B When in use, each panel can be folded inward toward the back side or inner surface 28 of the middle panel 18, and can be opened outward for placement on the wearer's face. Figures 1C to 1D When the mask body 12 is changed from its open configuration to its closed configuration, or vice versa, the upper panel 16 and the lower panel 20 rotate about the first dividing line 24 and the second dividing line 26, respectively. In this sense, the first dividing line 24 and the second dividing line 26 act as the first hinge or axis of the upper panel 16 and the second hinge or axis of the lower panel 20, respectively. Therefore, the tabs assist the user in pulling the panel 20 from its folded state to open the mask body into an open, ready-to-use (or in-use) configuration.

[0037] The respirator 10 may also be provided with a first side tab or flange 30 and a second side tab or flange 32 providing areas for securing the strap 14, which may include a strip or elastic band 34. The strip or elastic band 34 is pinned 35 to the mask body 12 at each opposite side to hold the mask body 12 against the wearer's face when the mask is worn. U.S. Patent D449,377 to Henderson et al. shows examples of tabs or flanges that can be used as areas for securing the strip. The strap can also be secured to the mask body by adhesion, gluing, welding, etc. Examples of compression elements that can be used to fasten the strap to the mask body using ultrasonic welding are described in U.S. Patents 6,729,332 and 6,705,317 to Castiglione. The elastic band can also be welded directly to the mask body without the use of a separate attachment element (see U.S. Patent 6,332,465 to Xue et al.). Examples of harnesses that may be used in conjunction with the present invention are described in U.S. Patent 5,394,568 to Brostron et al., U.S. Patent 5,237,986 to Seppala et al., and EP 608684A to Brostron et al. The upper panel 16 may be modified in its construction to increase resistance to airflow, thereby helping to prevent fogging of protective eyewear, as taught, for example, in U.S. Patent No. 9,770,611 entitled “Maintenance-Free Anti-Fog Respirator,” which is incorporated herein by reference.

[0038] The upper panel 16 of the mask body 12 may also include a nose clip 36 made of a stretchable metal strip, such as aluminum, which can be conformed to the wearer's facial configuration in the nasal region by finger pressure alone. Examples of suitable nose clips are shown and described in U.S. Patents 5,558,089 and 412,573 to Castiglione. Other examples are shown in U.S. Patent 8,171,933 and U.S. Patent Publication 2007 / 0068529.

[0039] Figure 1DSpecifically, the respirator 10 may further include a nasal foam 38 disposed inwardly along the inner periphery of the upper panel 16. The foam may also extend around the entire periphery of the mask body and may include a thermochromic fit indicator material that contacts the wearer's face when the mask is worn. Heat from facial contact causes the thermochromic material to change color, allowing the wearer to determine whether an appropriate fit has been established (see U.S. Patent 5,617,749 to Springett et al.). Examples of suitable nasal foams are shown in U.S. Patent Application Publications Nos. US2008 / 0099022 and US2008 / 0023006. The periphery of the mask body can be shaped along the top panel 16 to improve compatibility with protective eyewear, for example as taught in U.S. Patent No. 10,827,787 entitled “Maintenance-Free Respirator That Has Concave Portions on Opposing Sides Of Mask Top Section”, which is incorporated herein by reference.

[0040] Figure 2 An example of a conventional respirator construction is illustrated. Conventional respirators are typically formed from multiple layers of the same or different materials. For example, a respirator may be formed from: a smooth inner layer 110, which is used to avoid irritating the user's face; one or more filter layers 120, which are designed to filter out particulate matter, aerosols, and / or gaseous contaminants; and a reinforcing layer 130, which is selected to maintain the 3D shape of the respirator during use (e.g., as shown in the image). Figure 1C and Figure 1D (as illustrated); and a cover layer 140, which is used to embed loose fibers or for aesthetic reasons. In some cases, some of these layers include a meltblown nonwoven medium. In some cases, some layers are spunbond layers. In many cases, the different layers have different compositions (made from different starting materials in different ways). The different layers must also be bonded together, for example, using adhesive bonding and / or ultrasonic welding.

[0041] Combining multiple layers to form a disposable respirator requires additional mechanical steps, consumes more materials, and increases the cost of the resulting product. However, each of the different types of layers 110-140 serves a different functional or aesthetic purpose. The inner layer 110 is typically a smooth meltblown mesh. The filter layer 120 can be an electret meltblown mesh that provides filtration properties. The reinforcing layer can be a rigid spunbond mesh that provides stiffness, and the outer cover layer can be a lightweight spunbond mesh that provides strength and protection.

[0042] It is desirable to provide individual layers of respirator material with different functionalities, ranging from 110 to 140 layers. Each individual layer of respirator material can have a uniform composition throughout its volume. Individual layers of respirator material can be manufactured using meltblown technology, spunbond technology, or a combination of both.

[0043] Individual layers of respirator material must meet a variety of requirements typically provided by multiple different media sheets. Individual layers of respirator material must have sufficient tear strength. Individual layers of respirator material must have sufficient stiffness to maintain stability when the user breathes through the respirator. Figure 1D The general shape illustrated, such as the respirator, does not undergo significant collapse. Traditionally, respirators require reinforcing layers in addition to the filter media. For example, U.S. Patent 6,123,077 describes a multi-layered construction that incorporates a reinforcing mesh in addition to the filter layer.

[0044] Individual layers of respirator material must also possess satisfactory filtration efficiency. For example, a single layer of respirator material may meet one or more NIOSH particulate filter respirator classifications, such as N95, N99, N100, R95, R99, R100, P95, P99, and / or P100. Individual layers of respirator media may also meet the respirator requirements of FFP1, FFP2, and / or FFP3 EN 149 standards. Individual layers of respirator media may also meet the Chinese KN95 standard. Respirators made using the media described herein may also meet additional filtration efficiency tests from other regulatory agencies or jurisdictions.

[0045] The same media that meets filtration efficiency requirements should also have a smooth surface that comes into contact with the user's face to reduce irritation. The media should also be a non-linting material. For example, linting can be measured using the Tabor abrasion test.

[0046] The respirator according to the embodiment described herein is formed from a single-piece filter medium that has high filtration efficiency, high stiffness, high tear strength, and a low-fuzzing or non-fuzzing surface.

[0047] Some respirators have been formed with a single layer of material, such as the single layer described in U.S. Patent 9,770,058 to Angadijivand. However, respirators according to embodiments herein are formed from a significantly lighter nonwoven web with a basis weight of approximately 100 gsm. Using meltblown technology, it has been difficult to achieve a lightweight web with sufficient tear strength. Spunbond technology can produce nonwoven webs with high tear strength, but obtaining fibers with the low effective diameter required for good filtration efficiency at a low basis weight presents challenges.

[0048] The respirator filter media described in this embodiment uses a single layer of relatively low basis weight nonwoven web to meet filtration, stiffness, and tear strength requirements.

[0049] Some advantages of single-layer construction over multi-layer construction include, but are not limited to, reduced costs due to simpler construction and less material required. Single-layer construction can also be lighter, allowing for a reduced pressure drop in the respirator construction compared to multi-layer construction, thus allowing for easier breathability and greater comfort when worn.

[0050] Single-layer construction can also be a more sustainable option, requiring less material due to reduced basis weight and less resin in its construction. In some embodiments described herein, the flat-fold respirator is formed from less than 8 grams of material, or even less than 7 grams, or even less than 6 grams. A conventional 5-layer, 5-fold respirator may have a corresponding weight of approximately 9 to 10 grams.

[0051] Additionally, single-layer respirators offer lower thermal resistance and better moisture permeability compared to conventional multi-layer respirators, making them more comfortable to wear.

[0052] The respirator according to the embodiments herein is formed from a single layer of filter media. The filter media is a monolithic structure having a uniform composition throughout its entire volume. The filter media according to the embodiments herein has a substantially flat surface. The filter media in the embodiments herein is formed from fibers having a unimodal distribution. Some prior respirator designs (such as those described in U.S. Patent 9,770,058, published September 26, 2017, and U.S. Patent 10,575,571, published March 3, 2020) describe a construction using a bimodal fiber distribution.

[0053] Figure 3 A method for forming a respirator according to the embodiment described herein is illustrated. Figures 1A to 1D An example of a respirator design that can be formed using the respirator media described herein is illustrated. However, it is clearly envisioned that other respirator designs may also benefit from the media described herein.

[0054] At frame 310, a material for forming the nonwoven web is obtained. In some embodiments, this material may comprise polypropylene.

[0055] At frame 320, a nonwoven web is formed. The formed nonwoven web may have a basis weight of at least about 60 gsm. In some embodiments, the formed nonwoven web has a basis weight of less than about 150 gsm. In some embodiments, the formed nonwoven web has a basis weight between about 80 gsm and about 120 gsm, or between about 90 gsm and about 110 gsm.

[0056] The formed nonwoven web may have a thickness between about 25 mils and about 50 mils. The formed nonwoven web may have a solids content of at least about 9%. The formed nonwoven web may have a solids content of less than about 15%. The formed nonwoven web may include fibers with an effective fiber diameter of at least about 8 µm. The formed nonwoven web may include fibers with an effective fiber diameter of less than about 15 µm. The formed nonwoven web may have a glystiffness of at least about 350 mg. The formed nonwoven web may have a glystiffness of less than about 500 mg.

[0057] For example, the nonwoven web of this disclosure can be prepared by wet web forming technology, carding web forming technology, airflow web forming technology, jet web forming technology, spunbond technology, spunmelt technology or meltblown technology or combinations thereof.

[0058] The meltblown microfibers that can be used in this disclosure can be prepared as described in Van A. Wente's "Superfine Thermoplastic Fibers" (Industrial Engineering Chemistry, Vol. 48, pp. 1342-1346) and Naval Research Laboratories Report No. 4364 entitled "Manufacture of Super Fine Organic Fibers" published on May 25, 1954, by Van A. Wente et al.

[0059] Spunbond microfibers can be formed using a spunbond process in which one or more continuous polymer-free fibers are extruded into a collector, as described, for example, in U.S. Patent Nos. 4,340,563 and 8,162,153 and U.S. Patent Publication No. 2008 / 0038976.

[0060] In some embodiments described herein, a combination of one or more of the following processes is used to form a web: wet web forming, carding web forming, airflow web forming, jet web forming, spunbonding, spunmelt, or meltblown web forming.

[0061] The formation of the web may also include a calendering step. Calendering may include applying heat and / or high pressure to weld the fibers into a single layer within the respirator medium.

[0062] According to the embodiments described herein, the disposable respirator is formed from a single layer of filter media that at least meets the N95 filtration efficiency standard. The respirator is formed from one or more panels. Each panel is formed from a medium having a uniform composition across the surfaces of one or more panels.

[0063] In some embodiments described herein, a single-layer respirator is a flat-fold respirator with two or more panels, each panel being formed from a single layer of nonwoven material that at least meets the N95 standard set by NIOSH.

[0064] In some embodiments herein, a single layer of the filter media is formed of a material having a basis weight of at least about 60 gsm. In some embodiments herein, a single layer of the filter media has a basis weight of less than about 150 gsm. In some embodiments herein, a single layer of the filter media has a basis weight between about 100 gsm and about 120 gsm.

[0065] In some embodiments described herein, the respirator weighs less than 8 grams when fully assembled with the harness. The total weight of the assembled respirator may be less than 7 grams. The total weight of the assembled respirator may even be less than 6.5 grams. The total weight of the assembled respirator may even be less than 6 grams.

[0066] In some embodiments described herein, a single layer of the nonwoven filter media has a thickness of at least about 25 mils (0.64 mm). In some embodiments described herein, a single layer of the nonwoven filter media has a thickness of less than about 50 mils (1.3 mm).

[0067] In some embodiments of this invention, a single layer of the nonwoven filter media has a solids content of at least about 9%. In some embodiments of this invention, a single layer of the nonwoven filter media has a solids content of less than about 15%. In some embodiments of this invention, a single layer of the nonwoven filter media has a solids content of less than about 12%. In some embodiments of this invention, a single layer of the nonwoven filter media has a solids content of about 10%. In some embodiments of this invention, a single layer of the nonwoven filter media has a solids content of about 11%. In some embodiments of this invention, a single layer of the nonwoven filter media has a solids content of about 12%.

[0068] In some embodiments described herein, a single layer of the nonwoven filter media has an effective fiber diameter of at least about 8 µm. In some embodiments, a single layer of the nonwoven filter media has an effective fiber diameter of less than about 15 µm. In some embodiments, a single layer of the nonwoven filter media has an effective fiber diameter of less than about 12 µm. In some embodiments, a single layer of the nonwoven filter media has an effective fiber diameter of less than about 10 µm.

[0069] In some embodiments described herein, a single layer of the nonwoven filter media has a glystiffness of at least about 350 mg. In some embodiments described herein, a layer of the nonwoven filter media has a glystiffness of less than about 550 mg.

[0070] In some embodiments described herein, the flat-fold disposable respirator experiences a pressure drop of at least about 7 mm H2O. In some embodiments described herein, the flat-fold disposable respirator experiences a pressure drop of less than about 12.5 mm H2O. In some embodiments described herein, the flat-fold disposable respirator experiences a pressure drop of less than about 10 mm H2O.

[0071] In some embodiments described herein, a single layer of the nonwoven filter media has a tensile strength of at least 750 g when measured in the transverse direction. In some embodiments described herein, a single layer of the nonwoven filter media has a tensile strength of at least 750 g when measured in the machine direction.

[0072] In some embodiments described herein, individual layers of the nonwoven filter media are made of a lint-free or substantially lint-free material.

[0073] The respirator made according to the embodiments described herein is capable of filtering at least 95% of airborne particles with a median aerodynamic diameter of 0.3 µm. The respirator made according to the embodiments described herein is capable of filtering at least 99% of airborne particles with a median aerodynamic diameter of 0.3 µm. The respirator made according to the embodiments described herein is capable of filtering at least 99.9% of airborne particles with a median aerodynamic diameter of 0.3 µm.

[0074] The respirator made according to the embodiments described herein is more comfortable for the wearer than a corresponding multi-layer respirator construction. For example, a single layer of the filter medium will have lower thermal resistance than a corresponding multi-layer mesh construction. Similarly, a single-layer mesh construction will have a higher water vapor transfer rate than a corresponding multi-layer fiber mesh construction. This allows less heat and moisture to be retained in the wearer's breathing space (between the respirator and the user's face).

[0075] The respirator materials in the embodiments described herein may be suitable for particulate or gas and vapor types, and / or may be a barrier layer that prevents liquid from shifting from one side of the filter layer to the other, thus preventing, for example, liquid aerosols or liquid splashes from penetrating the filter layer. The respirator materials described in the embodiments herein typically have a low pressure drop (e.g., less than about 20 mm H2O to 30 mm H2O at a face velocity of 13.8 cm / s) to minimize the breathing effort of the mask wearer. The respirator media in the embodiments described herein are both flexible and have sufficient shear strength so that they substantially maintain their structure under the intended use conditions. The formed nonwoven web may comprise one or more webs of fine inorganic fibers (such as glass fibers) or polymer synthetic fibers. The synthetic fiber web may comprise electret charged polymer microfibers produced by processes such as meltblowing. Electret charged polyolefin microfibers formed from polypropylene may provide specific practicality for particulate trapping applications.

[0076] Breathing media can take many shapes and forms. Breathing media typically have a thickness of about 0.2 mm to 1 cm, more typically about 0.3 mm to 0.5 cm, and can be a planar mesh or a corrugated mesh with an enlarged surface area relative to the forming layer (see, for example, U.S. Patents 5,804,295 and 5,656,368 to Braun et al.).

[0077] The respirator media described herein include charged media. Meltblown fiber webs, such as Wente, Van A's Superfine Thermoplastic Fibers (Industrial Engineering Chemistry, Vol. 48, p. 1342 and follow-up pages (1956)), are particularly useful when in the form of permanently charged (electret) materials (see, for example, U.S. Patent No. 4,215,682 to Kubik et al.). These meltblown fibers can be microfibers having an effective fiber diameter of less than about 20 micrometers (μm), typically about 1 µm to 12 μm. Particularly preferred are meltblown webs comprising fibers formed from polypropylene, poly(4-methyl-1-pentene), and combinations thereof. Charged fibrillated film fibers are also suitable, as are rosin-wool and glass fiber webs or solution-blown webs, or electrostatically sprayed fiber webs, particularly in the form of microfilms, as taught in van Turnhout's U.S. Patent Re. 31,285. Fibers can be charged by contacting them with water, as disclosed in U.S. Patents 6,824,718 to Eitzman et al., 6,783,574 to Angadjivand et al., 6,743,464 to Insley et al., 6,454,986 and 6,406,657 to Eitzman et al., and 6,375,886 and 5,496,507 to Angadjivand et al. Fibers can also be charged by corona charging, as disclosed in U.S. Patent 4,588,537 to Klasse et al., or by turbocharging, as disclosed in U.S. Patent 4,798,850 to Brown. Furthermore, additives can be incorporated into the fibers to enhance the filtration performance of the fiber web prepared by the water charging method (see U.S. Patent 5,908,598 to Rousseau et al.). Specifically, fluorine atoms can be disposed on the surface of the fibers in the filter layer to improve filtration performance in oil mist environments (see U.S. Patents 6,398,847 B1, 6,397,458 B1, and 6,409,806 B1 to Jones et al.). Typical basis weights of meltblown electret filter layers range from approximately 15 g / m² to 100 g / m². When charged according to, for example, the technique described in the '507 patent, the basis weight can be approximately 20 g / m². 2 Up to 40g / m 2 and approximately 10g / m 2 Up to 30g / m 2 .

[0078] At frame 330, a respirator is formed from a medium. Forming the respirator may include forming multiple panels and connecting the multiple panels together (e.g., Figures 1A to 1D (The illustrated respirator has a top panel, middle panel, and bottom panel). Where it is necessary to connect different panels, welding, adhesives, nailing, or another connecting mechanism that substantially forms and maintains a seal between the panels, forcing air through the filter media during use, can be used for connection.

[0079] Forming a respirator may also include a shaping step, such as forming a cup-shaped respirator. However, it is explicitly envisioned that the medium described herein can be used to form a variety of respirator styles, including vertically folded style 334, horizontally folded style 332, or other styles 336.

[0080] The medium described herein is suitable for forming pleated respirators (e.g., available from 3M under the trade name VFLEX). ® (Obtained), such as the pleated respirator illustrated in Figures 1-4 and column 4, line 25-column 5, line 29 of U.S. Patent No. 8,640,704, which is incorporated herein by reference. The pleated respirator is foldable along a centerline and has a mask body having a dividing line extending laterally relative to a longitudinal axis. One or more weld patterns may be disposed above the dividing line and not across it. One or more weld patterns may be disposed on each side of the longitudinal axis. In some embodiments, additional one or more weld patterns are disposed below the dividing line on each side of the longitudinal axis and do not intersect the dividing line. Any, all, or a subset of the weld patterns are two-dimensional closed patterns. The weld patterns of the pleated respirator may have a truss geometry, having one or more triangles with sharp or rounded corners. Weld patterns may also have other shapes. Weld pattern shapes may be of various sizes, orientations, or both. In some embodiments, shapes may overlap, share edges or corners, or be nested within each other.

[0081] The respirator medium described herein is applicable to "duckbill" type respirators, such as the respirator described in U.S. Patent 5,322,061 granted to Brunson. Such a respirator can be characterized as having a generally trapezoidal portion forming the upper half of the respirator that contacts the wearer's nose, and a generally trapezoidal portion forming the lower half of the respirator that contacts the wearer's chin.

[0082] It is explicitly envisioned that the breathing design described herein may also benefit from corrugated media, such as those described in U.S. Provisional Application 63 / 496002, filed April 13, 2023, and U.S. Provisional Application 63 / 607197, filed December 7, 2023, both of which are incorporated herein by reference. For example, corrugated media can be used for face seals and / or headbands. Additionally, corrugated media can be used for one or more panels in a multi-panel construction. For example, for Figures 1A to 1D The respirator design includes a pleated medium that can be used on the lower panel.

[0083] Forming a respirator may also include adding peripheral components such as strips, nasal foam, nasal clips, and / or straps to the body of the respirator.

[0084] In some embodiments, the respirator of this invention has anti-fogging properties in its upper and lower panels. Examples of such anti-fogging layers are taught in U.S. Patent No. 9,770,611 entitled “Maintenance-Free Respirator,” which is incorporated herein by reference.

[0085] The respirator may also include an optional exhalation valve that allows the user to easily exhale air. Exhalation valves that exhibit extremely low pressure drop during exhalation are described in: U.S. Patents 7,188,622, 7,028,689, and 7,013,895 to Martin et al.; U.S. Patents 7,117,868, 6,854,463, 6,843,248, and 5,325,892 to Japuntich et al.; and U.S. Patent 6,883,518 to Mittelstadt et al. The exhalation valve can be fixed to the center panel by various means, preferably near the center of the center panel, including acoustic welding, adhesive bonding, mechanical clamping, etc. (see, for example, U.S. Patents 7,069,931, 7,007,695, 6,959,709 and 6,604,524 to Curran et al. and EP1,030,721 to Williams et al.).

[0086] The flat-fold maintenance-free respirator of the present invention can be manufactured according to the process described in U.S. Patents 6,123,077, 6,484,722, 6,536,434, 6,568,392, 6,715,489, 6,722,366, 6,886,563, and 7,069,930 to Bostock et al., and U.S. Patent Publication No. US2006 / 0180152A1 and EP0814871B1. The respirator manufacturing process will include supplying pre-cut material for reinforcing layers, which will be bonded between other material meshes forming the respirator. The reinforcing layers can be held in place between the layers and between certain weld lines.

[0087] Additional processing can be performed at box 340. For example, the respirator can be encapsulated, and / or text can be printed onto the surface of the respirator.

[0088] A disposable, foldable respirator is presented, comprising a mask body including multiple panels that can be folded toward each other and unfolded into an open configuration. The mask body includes a single layer of electrically charged filtering material. The multiple panels include an upper panel, a lower panel, and a middle panel. The middle panel is connected to the upper and lower panels. The respirator filters at least 95% of airborne particles with a median aerodynamic diameter of 0.3 µm. Straps are attached to the mask body.

[0089] The respirator can be implemented such that the charged filter material comprises a uniform composition across the material surface.

[0090] The respirator can be implemented such that the charged filter material comprises a uniform composition throughout the entire material depth.

[0091] The respirator can be implemented such that the respirator in the open configuration is configured to maintain the shape of the mask body during use.

[0092] The respirator can be configured such that the charged filter material comprises a basis weight of at least about 60 gsm. The respirator can be configured such that the charged filter medium comprises a basis weight of less than about 150 gsm. The respirator can be configured such that the charged filter medium comprises a basis weight between about 80 gsm and about 120 gsm.

[0093] The respirator can be implemented such that the charged filter medium has a mesh thickness between 25 mils and 50 mils.

[0094] The respirator can be configured such that the charged filter medium has a stiffness of at least about 350 mg. The respirator can be configured such that the charged filter medium has a stiffness of less than about 450 mg. The respirator can be configured such that the charged filter medium has a stiffness of less than about 500 mg.

[0095] The respirator can be configured such that the charged filter medium has a solids content of at least about 9%. The respirator can be configured such that the charged filter medium has a solids content of at least about 11%. The respirator can be configured such that the charged filter medium has a solids content of less than about 12%. The respirator can be configured such that the charged filter medium has a solids content of less than about 15%.

[0096] The respirator can be configured such that the charged filter medium has an average flow resistance of at least about 7 mm H2O at 85 liters per minute. The respirator can also be configured such that the charged filter medium has an average flow resistance of less than about 12.5 mm H2O at 85 liters per minute.

[0097] The respirator can be implemented such that the charged filter medium includes a calendered charged filter medium.

[0098] The respirator can be implemented such that the charged filter medium contains polypropylene.

[0099] The respirator can be configured such that it includes a harness and has a total weight of less than 8 grams. The respirator can be configured such that it includes a harness and has a total weight of less than 7 grams. The respirator can be configured such that it includes a harness and has a total weight of less than 6.5 grams. The respirator can be configured such that it includes a harness and has a total weight of less than 6 grams.

[0100] The respirator can be configured such that a single layer of the charged filter medium comprises fibers having an effective fiber diameter of at least about 8 µm. The respirator can be configured such that a single layer of the charged filter medium comprises fibers having an effective fiber diameter of less than about 15 µm. The respirator can be configured such that a single layer of the charged filter medium comprises fibers having an effective fiber diameter of less than about 12 µm. The respirator can be configured such that a single layer of the charged filter medium comprises fibers having an effective fiber diameter of less than about 10 µm.

[0101] The respirator can be configured such that the tensile strength of a single layer of the charged filter medium is at least 750 g in the transverse direction. The respirator can also be configured such that the tensile strength of a single layer of the charged filter medium is at least 750 g in the machine direction.

[0102] The respirator can be implemented such that it includes a non-hairless surface.

[0103] The respirator can be implemented such that the upper and lower panels are configured to fold toward the middle panel to place the respirator in a closed configuration, and wherein the upper and lower panels are configured to unfold away from the middle panel to place the respirator in an open configuration.

[0104] The respirator may also include a valve, a nose clip, or nasal foam.

[0105] The respirator can be configured to filter at least 99% of airborne particles with a median aerodynamic diameter of 0.3 µm. The respirator can also be configured to filter at least 99.9% of airborne particles with a median aerodynamic diameter of 0.3 µm.

[0106] A disposable respirator is presented, comprising a mask body having an inner surface and an outer surface. The mask body is configured such that the inner surface receives the user's exhaled air, and the outer surface is exposed to ambient air. The mask body includes a single layer of filter media, wherein the single layer of filter media includes an inner surface of a thickness separated from the outer surface. The respirator filters at least 95% of airborne particles having a median aerodynamic diameter of 0.3 µm.

[0107] This disposable respirator can be implemented such that a single layer of the filter medium has a uniform composition across the outer surface.

[0108] This disposable respirator can be implemented such that a single layer of the filter medium has a uniform composition throughout its thickness.

[0109] The disposable respirator can be configured such that the charged filter material comprises a basis weight of at least about 60 gsm. The disposable respirator can be configured such that the charged filter medium comprises a basis weight of less than about 150 gsm. The disposable respirator can be configured such that the charged filter medium comprises a basis weight between about 80 gsm and about 120 gsm.

[0110] The disposable respirator can be configured such that the charged filter medium has a mesh thickness between 25 mils and 50 mils.

[0111] The disposable respirator can be configured such that the charged filter medium has a stiffness of at least about 350 mg. The disposable respirator can be configured such that the charged filter medium has a stiffness of less than about 450 mg. The disposable respirator can be configured such that the charged filter medium has a stiffness of less than about 500 mg.

[0112] The disposable respirator can be configured such that the charged filter medium has a solids content of at least about 9%. The disposable respirator can be configured such that the charged filter medium has a solids content of at least about 11%. The disposable respirator can be configured such that the charged filter medium has a solids content of less than about 12%. The disposable respirator can be configured such that the charged filter medium has a solids content of less than about 15%.

[0113] The disposable respirator can be configured such that the charged filter medium has an average flow resistance of at least about 7 mmH2O at 85 liters per minute. The disposable respirator can also be configured such that the charged filter medium has an average flow resistance of less than about 12.5 mmH2O at 85 liters per minute. Furthermore, the disposable respirator can be configured such that the charged filter medium comprises calendered charged filter medium.

[0114] The disposable respirator can be implemented such that the charged filter medium contains polypropylene.

[0115] The disposable respirator can be configured such that it includes a strap and has a total weight of less than 8 grams. The disposable respirator can be configured such that it includes a strap and has a total weight of less than 7 grams. The disposable respirator can be configured such that it includes a strap and has a total weight of less than 6.5 grams. The disposable respirator can be configured such that it includes a strap and has a total weight of less than 6 grams.

[0116] The disposable respirator can be configured such that a single layer of the charged filter medium comprises fibers having an effective fiber diameter of at least about 8 µm. The disposable respirator can be configured such that a single layer of the charged filter medium comprises fibers having an effective fiber diameter of less than about 15 µm. The disposable respirator can be configured such that a single layer of the charged filter medium comprises fibers having an effective fiber diameter of less than about 12 µm. The disposable respirator can be configured such that a single layer of the charged filter medium comprises fibers having an effective fiber diameter of less than about 10 µm.

[0117] The disposable respirator can be implemented such that the tensile strength of a single layer of the charged filter medium is at least 750g in the transverse direction.

[0118] The disposable respirator can be implemented such that the tensile strength of a single layer of the charged filter medium is at least 750g in the machine direction.

[0119] The disposable respirator can be implemented such that it includes a non-lint-free surface.

[0120] The disposable respirator can be implemented such that the mask body includes multiple panels that can be folded toward each other and unfolded into an open configuration, wherein each of the multiple panels includes a single layer of charged filter media.

[0121] The disposable respirator can be implemented such that multiple panels include an upper panel, a lower panel, and a middle panel, wherein the middle panel is connected to the upper panel and the lower panel.

[0122] The disposable respirator according to claim 1, further comprising a valve, a nose clip, or a nasal foam.

[0123] The disposable respirator can be configured to filter at least 99% of airborne particles with a median aerodynamic diameter of 0.3 µm. The disposable respirator can also be configured to filter at least 99.9% of airborne particles with a median aerodynamic diameter of 0.3 µm.

[0124] The disposable respirator can be implemented such that it is a horizontally folding respirator.

[0125] The disposable respirator can be implemented such that the disposable respirator is a cup-shaped respirator, and wherein the cup-shaped respirator includes a housing.

[0126] The disposable respirator can be implemented such that it is a vertically folding respirator.

[0127] The disposable respirator can be implemented such that it is a pleated respirator.

[0128] The disposable respirator can be configured to be a duckbill respirator.

[0129] A method for forming a disposable respirator is presented, comprising forming a nonwoven web and forming a mask body of the disposable respirator from the nonwoven web. The nonwoven web has a uniform composition, which is at least partially defined as having a basis weight of at least about 60 gsm and less than about 150 gsm, a glystiffness of at least about 350 mg, and a solids content of at least about 9%. The mask body is formed from a single layer of the nonwoven web, such that the single layer of the nonwoven web comprises both the outer surface and the inner surface of the disposable respirator. The disposable respirator has an airflow resistance of less than 12.5 mmH2O, and wherein the disposable respirator filters at least 95% of airborne particles having a median aerodynamic diameter of 0.3 µm.

[0130] This method can be implemented such that the formation of the mask body includes a welded nonwoven mesh.

[0131] This method can be implemented such that forming the mask body includes applying nails to a nonwoven web.

[0132] This method can be implemented such that forming the mask body includes applying a valve to the mask body.

[0133] This method can be implemented such that forming the mask body includes applying a strap to the mask body.

[0134] This method can be implemented such that forming a nonwoven web includes calendering the nonwoven web.

[0135] The method can be implemented such that forming the mask body includes forming a plurality of panels, each panel comprising a single layer of nonwoven mesh.

[0136] This method can be implemented such that forming the mask body includes joining multiple panels together to form the shape of the mask body.

[0137] This method can be implemented such that the nonwoven web has a basis weight of at least about 80 gsm and less than about 120 gsm.

[0138] This method can be implemented such that the nonwoven web has a thickness of at least about 25 mils. This method can also be implemented such that the nonwoven web has a thickness of less than about 50 mils.

[0139] This method can be implemented such that the nonwoven web is formed from fibers having an effective fiber diameter of less than about 15 µm. This method can be implemented such that the nonwoven web is formed from fibers having an effective fiber diameter of at least about 8 µm. This method can be implemented such that the nonwoven web is formed from fibers having an effective fiber diameter of less than about 12 µm. This method can be implemented such that the nonwoven web is formed from fibers having an effective fiber diameter of less than about 10 µm. This method can be implemented such that the disposable respirator exhibits an airflow resistance of less than about 12.5 mm H2O. This method can be implemented such that the disposable respirator exhibits an airflow resistance of at least about 7 mm H2O.

[0140] This method can be implemented such that the disposable respirator has a total weight of less than about 8 grams. This method can be implemented such that the disposable respirator has a total weight of less than about 7 grams. This method can be implemented such that the disposable respirator has a total weight of less than about 6.5 grams.

[0141] This method can be implemented to give the nonwoven web a transverse tensile strength of at least 750g.

[0142] This method can be implemented to give the nonwoven web a machine-direction tensile strength of at least 750g.

[0143] This method can be implemented to give the nonwoven web a glystiffness of less than about 500 mg.

[0144] This method can be implemented to make the nonwoven web a non-pilling nonwoven web.

[0145] This method can be implemented such that a disposable respirator filters at least 99% of airborne particles with a median aerodynamic diameter of 0.3 µm. This method can also be implemented such that a disposable respirator filters at least 99.5% of airborne particles with a median aerodynamic diameter of 0.3 µm.

[0146] This method can be implemented such that the formation of nonwoven webs includes spunbond technology, meltblown technology and / or combinations thereof.

[0147] A nonwoven respirator filter medium is presented, comprising: a basis weight between about 60 gsm and about 150 gsm, a solids content between about 9% and about 15%, multiple fibers having an effective fiber diameter between about 8 µm and about 15 µm, a glystiffness between about 350 mg and about 500 mg, and a tensile strength of at least 750 g in the transverse or machine direction.

[0148] The nonwoven respirator filter medium can be made to have sufficient stiffness so that when a single layer is formed into the shape of the mask body, the respirator filter medium maintains the shape of the mask body during use without collapsing.

[0149] The nonwoven respirator filter media can be made such that the basis weight is between approximately 80 gsm and approximately 120 gsm.

[0150] The nonwoven respirator filter media can be configured such that the solids content is between approximately 9% and approximately 12%.

[0151] The nonwoven respirator filter media can be configured such that the effective fiber diameter is between approximately 8µm and approximately 10µm.

[0152] The nonwoven respirator filter medium can be made such that the tensile strength of a single layer of the charged filter medium is at least 750 g in the transverse direction.

[0153] The nonwoven respirator filter medium can be made such that the tensile strength of a single layer of the charged filter medium is at least 750 g in the machine direction.

[0154] The nonwoven respirator filter media can be made such that the respirator includes a lint-free surface.

[0155] The nonwoven respirator filter media can be implemented such that multiple fibers contain polypropylene.

[0156] The nonwoven respirator filter medium can be made to allow multiple fibers to exhibit quasi-permanent charges.

[0157] The nonwoven respirator filter medium can be implemented such that multiple fibers include electret fibers.

[0158] The nonwoven respirator filter medium can be configured such that it is a calendered nonwoven respirator filter medium.

[0159] The nonwoven respirator filter medium can be configured such that it comprises a uniform composition.

[0160] Test methods

[0161] The following test methods were used to evaluate the media and respirator examples. Unless otherwise stated, all initial DOP permeability and pressure drop tests for the Example (EX) and Comparative Example (CE) networks were performed at a face velocity of 13.8 cm / sec. The media network performance listed in Table ## is based on actual measurements according to the listed test methods.

[0162] Effective fiber diameter (EFD)

[0163] The effective fiber diameter can be determined according to Davies, CN, The Separation of Airborne Dust Particles (Proceedings of the Institution of Mechanical Engineers, London, 1952, 1B).

[0164] Solid content

[0165] Solids ratio is a nonwoven web property that is negatively correlated with density, as well as web permeability and porosity (low solids ratio corresponds to high permeability and high porosity), and is defined by the following formula 1.

[0166]

[0167] pressure drop

[0168] The pressure drop and permeation percentage of the media network can be determined using a test sample containing NaCl or DOP (dioctyl phthalate) particles delivered at a flow rate of 85 L / min or LPM, and using TSI. ™ The Model 8130 high-speed automatic filter tester (available from TSI Inc., Shoreview, Minnesota, USA) is used for evaluation. An MKS pressure transducer (available from MKS Instruments, Andover, Massachusetts, USA) can be used to measure the pressure drop (dP, mm H2O) through the filter medium or filter sample.

[0169] DOP penetration

[0170] For DOP testing, aerosols can contain particles with a nominal diameter of approximately 0.185 µm and a target concentration of approximately 100 mg / m³. 3 The automatic filter tester can operate with both the heater and particle neutralizer off. The initial DOP permeability and pressure drop test lasts approximately 21 seconds.

[0171] NaCl or DOP particles are forced to pass through a 11.4 cm diameter or 102 cm opening at a rate of 85 LPM. 2 The medium sample.

[0172] The percentage of DOP or NaCl penetration is defined by Formula 2:

[0173]

[0174] Tensile strength

[0175] For tensile strength testing of mesh. The methods outlined in ASTM D5034 can be used. Examples of suitable test conditions include mesh samples of 30mm × 150mm or 1 inch × 4 inches in size, mounted between clamps at a distance of 100mm, and pulled at a speed of 300mm / min or 500mm / min.

[0176] N95 respirators designed for use by healthcare workers in healthcare settings to protect them from large droplets, splashes, or sprays of bodily fluids or other hazardous fluids must meet the Category II device regulations according to FDA 21 CFR 878.4040 and must meet the fluid resistance test according to the method outlined in ASTM F1862, which simulates high-velocity synthetic blood flow corresponding to pressures of 80 mmHg, 120 mmHg, and 160 mmHg. Higher pressures result in a higher rating. For example, Level 1 indicates resistance at 80 mmHg, and Level 3 indicates resistance at 160 mmHg. In some embodiments, the respirators described herein have a Level 1, 2, or 3 fluid resistance rating.

[0177] The measured values ​​are presented in the Examples section.

[0178] Example

[0179] Example 1 .

[0180] In this embodiment, the mesh properties of a single layer of the filter medium used are compared to those of filter media commonly used in certified respirators. Comparative Examples 1-5 represent single filter layers taken from different commercially available media suitable for respirators with N95, FFP2, or higher certifications. It should be noted that all respirators in Examples 1-5 are commercially available multilayer respirator constructions. The measured properties are EFD (effective fiber diameter), solids percentage, basis weight in grams per square meter, and pressure drop in mmH2O.

[0181] Examples EX-1 to EX-4 were formed as flat-fold respirators, and the permeability % of DOP aerosol was tested, the results of which are also shown in Table 1.

[0182] The permeability percentage of DOP aerosol at 85 lpm is also provided. The permeability data is the average of 5 parallel measurements.

[0183] The results show that the initial performance requirements of a certified respirator of the horizontal fold type can be achieved through a single layer of the filter media described in this paper.

[0184]

[0185] Example 2 .

[0186] In this embodiment, we converted the Ex-2 from the previous embodiment into a flat-fold respirator. This was done by first calendering the mesh against a smoothing roller at a calendering rate of 17%. The resulting pressure drop was 9.7 mmH2O, compared to 7.8 mmH2O in the previous embodiment. The calendered mesh became charged and was converted into a pattern simulating a flat-fold respirator. Using a test fixture designed for flat-fold respirators, a TSI 8130 was used to test the single-layer respirators against salt load, and these single-layer respirators were compared with those having a similar design to 3M Aura. ™ A comparison was made between the 9205+ folding respirator and the folding respirator. Relevant test data are provided in Table 2, and are the average of 5 parallel determinations.

[0187]

[0188] Example 3 .

[0189] The product name Aura can be obtained from 3M. ™ Four commercially available respirators were purchased for 9205+. The respirators were weighed in pairs, each with a standard PIP headband, and the results were averaged to obtain an average weight of 9.03g.

[0190] The four respirators from Examples 1-6 were weighed in pairs. Each respirator had a weight and Aura. ™ The 9205+ associated headbands were the same headbands, and the results were averaged to obtain an average weight of 6.016g.

[0191] Example 4 .

[0192] In this embodiment, the facial fit performance of respirators fabricated for Examples 2, Ex-1, and CE-4 was evaluated.

[0193] A face fit test is used to determine the amount of leakage between a respirator user's face and the tightly fitting seal of the respirator. The amount of face seal leakage between the respirator and the user's face is quantified by measuring the concentration of test aerosols (e.g., NaCl particles suspended in the air) on the inside and outside of the respirator. A usable face fit test has been developed that selectively detects particles 60 nanometers (nm) or smaller. See U.S. Patent No. 6,125,845 to Halvorson et al. A commercially available instrument (TSI PortaCount) is used for the face fit test. ® Pro+ (TSI Corporation, Shorvey, Minnesota, USA).

[0194] Thirteen samples each of Ex-1 and CE-4 were prepared for facial fit testing on human subjects. A sample probe fixation device (TSI) was attached to each sample to allow determination of the aerosol concentration within the sample during facial fit testing.

[0195] Facial fit testing was conducted in a large room. A NaCl aerosol was generated using a Model 8026 particle generator (TSI). The atomizer was adjusted to ensure sufficient particles were available to achieve a fit factor of at least 200.

[0196] For each fit test, the subject wore a respirator, which was attached to the fit testing system via a sample probe and tubing. The subject was then asked to perform eight exercises, as defined in 29 CFR 1910, 134, Appendix A, Part IA14. During these exercises, particle concentration data were collected from the fit testing system using a microcomputer. Data could also be obtained without a microcomputer by running the fit testing system in “counting mode” and manually recording data from the fit testing system reader. Specific exercises, their duration, and data collection protocols are shown in Table 3 below. Start and end times were measured in seconds after the start of the exercise.

[0197]

[0198] Fit factors were calculated for all exercises except for making faces. The fit factor was equal to the chamber aerosol concentration divided by the internal respirator aerosol concentration. For each exercise, the chamber aerosol concentration used was the average of chamber concentrations measured immediately before and after the internal respirator concentration. The mean fit factor for each subject wearing each sample respirator was obtained by calculating the harmonic mean of seven fit factors for the exercises: first normal breath, deep breath, head up / down movement, head left / right movement, rainbow message reading, waist bending, and second normal breath. The harmonic mean was obtained by calculating the reciprocal of the arithmetic mean of the reciprocals of the fit factors for each exercise. The results of facial fit tests using the CE-4 and EX-1 samples are shown in Table 4 below:

[0199]

[0200] Compared to CE-4, eight out of thirteen subjects showed significantly higher fit factors for the Ex-1 of this invention, indicating a significant reduction in facial seal leakage. In one subject (Subject 2), the fit factor was found to be substantially equivalent between CE-4 and Ex-1. Four out of the thirteen subjects tested (Subjects 4, 7, 10, and 12) had lower fit factors when wearing Ex-1 compared to when wearing CE-4.

[0201] Foreseeable modifications and alterations to the invention will be apparent to those skilled in the art without departing from its scope and spirit. The invention should not be limited to the embodiments shown in this application for illustrative purposes. In the event of any conflict or contradiction between the disclosure in this written specification and any document incorporated herein by reference, the written specification shall prevail.

[0202] In some embodiments, a disposable folding respirator includes a mask body having multiple panels that can be folded toward each other and unfolded into an open configuration. The mask body includes a single layer of charged filtering material. The multiple panels include an upper panel, a lower panel, and a middle panel, wherein the middle panel is connected to the upper and lower panels. The respirator filters at least 95% of airborne particles with a median aerodynamic diameter of 0.3 µm. A strap is attached to the mask body. The charged filtering material spans the material surface and may have a uniform composition throughout the material depth. The respirator in the open configuration can be configured to maintain the shape of the mask body during use. The charged filtering material may have a basis weight of at least about 60 gsm, less than about 150 gsm, or between about 80 gsm and about 120 gsm. The charged filter media may have a mesh thickness between 25 mils and 50 mils, a stiffness of at least about 350 mg, less than about 450 mg, or less than about 500 mg, and a solids content of at least about 9%, at least about 11%, less than about 12%, or less than about 15%. The charged filter media may have an average flow resistance of at least about 7 mmH2O or less than about 12.5 mmH2O at 85 liters per minute. The charged filter media may include calendered charged filter media and polypropylene. The respirator may include a harness and may have a total weight of less than 8 grams, less than 7 grams, less than 6.5 grams, or less than 6 grams. A single layer of the charged filter media may include fibers having an effective fiber diameter of at least about 8 µm, less than about 15 µm, less than about 12 µm, or less than about 10 µm. The tensile strength of a single layer of the charged filter media may be at least 750 g in the transverse or machine direction. The respirator may include a non-pilling surface. The upper and lower panels can be configured to fold toward the middle panel to place the respirator in a closed configuration, and unfold away from the middle panel to place the respirator in an open configuration. The respirator may also include a valve, a nose clip, or a nasal foam. The respirator can filter at least 99% or at least 99.9% of airborne particles with a median aerodynamic diameter of 0.3 µm. A disposable respirator includes a mask body having an inner surface and an outer surface, wherein the inner surface receives the user's exhalation, and the outer surface is exposed to ambient air. The mask body includes a single layer of filter media, wherein the inner surface and outer surface are separated by a thickness. The respirator filters at least 95% of airborne particles with a median aerodynamic diameter of 0.3 µm. The single layer of filter media spans the outer surface and may have a uniform composition over its entire thickness. The charged filter material may have a basis weight of at least about 60 gsm, less than about 150 gsm, or between about 80 gsm and about 120 gsm. The charged filter media may have a mesh thickness between 25 mils and 50 mils, a stiffness of at least about 350 mg, less than about 450 mg or less than about 500 mg, and a solids content of at least about 9%, at least about 11%, less than about 12% or less than about 15%.The charged filter medium may have an average flow resistance of at least about 7 mm H2O or less than about 12.5 mm H2O at 85 liters per minute. The charged filter medium may include calendered charged filter medium and polypropylene. The disposable respirator may include a harness and may have a total weight of less than 8 grams, less than 7 grams, less than 6.5 grams, or less than 6 grams. A single layer of the charged filter medium may include fibers having an effective fiber diameter of at least about 8 µm, less than about 15 µm, less than about 12 µm, or less than about 10 µm. The tensile strength of a single layer of the charged filter medium may be at least 750 g in the transverse or machine direction. The disposable respirator may include a non-pilling surface. The mask body may include multiple panels that can be folded toward each other and unfolded into an open configuration, wherein each of the multiple panels includes a single layer of the charged filter medium. The multiple panels may include a top panel, a bottom panel, and a middle panel, wherein the middle panel is connected to the top and bottom panels. The disposable respirator may also include a valve, a nose clip, or a nasal foam. A disposable respirator can filter at least 99% or at least 99.9% of airborne particles with a median aerodynamic diameter of 0.3 µm. The disposable respirator can be a horizontally folded respirator, a cup-shaped respirator with a shell, a vertically folded respirator, a pleated respirator, or a duckbill respirator. A method of forming a disposable respirator includes forming a nonwoven mesh with a uniform composition defined as having a basis weight of at least about 60 gsm and less than about 150 gsm, a glystiffness of at least about 350 mg, and a solids content of at least about 9%. The method includes forming a mask body from the nonwoven mesh, wherein the mask body is formed from a single layer of the nonwoven mesh such that the single layer includes both the outer and inner surfaces of the disposable respirator. The disposable respirator has an airflow resistance of less than 12.5 mmH2O and filters at least 95% of airborne particles with a median aerodynamic diameter of 0.3 µm. Forming the mask body may include welding a nonwoven mesh, applying staples, applying valves, applying straps, calendering the nonwoven mesh, forming multiple panels, and joining the panels together to form the shape of the mask body. The nonwoven mesh may have a basis weight of at least about 80 gsm and less than about 120 gsm, a thickness of at least about 25 mils and less than about 50 mils, and an effective fiber diameter of less than about 15 µm, at least about 8 µm, less than about 12 µm, or less than about 10 µm. The disposable respirator may exhibit an airflow resistance of less than about 12.5 mm H2O or at least about 7 mm H2O, and may have a total weight of less than about 8 grams, less than about 7 grams, or less than about 6.5 grams. The nonwoven mesh may have a transverse tensile strength of at least 750 g, a machine-direction tensile strength of at least 750 g, and a glyph stiffness of less than about 500 mg. The nonwoven mesh may be non-pilling. The disposable respirator can filter at least 99% or at least 99.5% of airborne particles with a median aerodynamic diameter of 0.3 µm.Forming a nonwoven web may include spunbond technology, meltblown technology, or a combination thereof. A nonwoven respirator filter medium includes: a basis weight between about 60 gsm and about 150 gsm, a solids content between about 9% and about 15%, fibers having an effective fiber diameter between about 8 µm and about 15 µm, glyph stiffness between about 350 mg and about 500 mg, and a tensile strength of at least 750 g in the transverse or machine direction. The respirator filter medium may have sufficient stiffness to maintain the shape of the mask body without collapsing during use. The basis weight may be between about 80 gsm and about 120 gsm. The solids content may be between about 9% and about 12%. The effective fiber diameter may be between about 8 µm and about 10 µm. The tensile strength of a single layer of the charged filter medium may be at least 750 g in the transverse or machine direction. The respirator may include a non-pilling surface. The fibers may comprise polypropylene and exhibit a quasi-permanent charge. The fibers may include electret fibers. Nonwoven respirator filter media can be calendered and comprises a uniform composition.

Claims

1. A nonwoven respirator filter medium, the nonwoven respirator filter medium comprising: Basis weight between approximately 60 gsm and approximately 150 gsm; Solid content between approximately 9% and approximately 15%; Multiple fibers with an effective fiber diameter between approximately 8µm and approximately 15µm; Glitrin levels between approximately 350 mg and approximately 500 mg; and Tensile strength of at least 750g in the transverse or machine direction.

2. The nonwoven respirator filter medium according to claim 1, wherein the respirator filter medium has sufficient stiffness such that when a single layer is formed into the shape of the mask body, the respirator filter medium maintains the shape of the mask body without collapsing during use.

3. The nonwoven respirator filter media according to claim 1 or 2, wherein the basis weight is between about 80 gsm and about 120 gsm.

4. The nonwoven respirator filter media according to any one of claims 1 to 3, wherein the solids content is between about 9% and about 12%.

5. The nonwoven respirator filter media according to any one of claims 1 to 4, wherein the effective fiber diameter is between about 8 µm and about 10 µm.

6. The nonwoven respirator filter medium according to any one of claims 1 to 5, wherein the tensile strength of a single layer of the charged filter medium is at least 750 g in the transverse direction.

7. The nonwoven respirator filter media according to any one of claims 1 to 6, wherein the respirator includes a non-pilling surface.

8. A disposable folding respirator, the respirator comprising: A face mask body comprising a plurality of panels foldable toward each other and unfoldable into an open configuration, wherein the face mask body comprises a single layer of charged filter material. The plurality of panels includes a top panel, a bottom panel, and a middle panel, wherein the middle panel is connected to the top panel and the bottom panel; The respirator filters at least 95% of airborne particles with a median aerodynamic diameter of 0.3 µm; and A strap is attached to the mask body.

9. The respirator of claim 8, wherein the charged filter material comprises a uniform composition across the material surface.

10. The respirator according to claim 8 or 9, wherein the charged filter material comprises a uniform composition throughout the material depth.

11. The respirator according to any one of claims 8 to 10, wherein the respirator in the open configuration is configured to maintain the shape of the mask body during use.

12. The respirator according to any one of claims 8 to 11, wherein the charged filter material comprises a basis weight of at least about 60 gsm.

13. The respirator according to any one of claims 8 to 12, wherein the charged filter medium comprises a basis weight of less than about 150 gsm.

14. The respirator according to any one of claims 8 to 13, wherein the charged filter medium comprises a basis weight between about 80 gsm and about 120 gsm.

15. The respirator according to any one of claims 8 to 14, wherein the charged filter medium comprises a mesh thickness between 25 mils and 50 mils.

16. The respirator according to any one of claims 8 to 15, wherein the charged filter medium has a stiffness of at least about 350 mg.

17. The respirator according to any one of claims 8 to 16, wherein the charged filter medium has a stiffness of less than about 450 mg.

18. A method of forming a disposable respirator, the method comprising: A nonwoven web is formed, wherein the nonwoven web has a uniform composition, the uniform composition being defined at least in part as having a basis weight of at least about 60 gsm and less than about 150 gsm, a glystiffness of at least about 350 mg and a solids content of at least about 9%. The face mask body of the disposable respirator is formed from the nonwoven web, wherein the face mask body is formed from a single layer of the nonwoven web, such that the single layer of the nonwoven web includes both the outer surface and the inner surface of the disposable respirator; and The disposable respirator has an airflow resistance of less than 12.5 mmH2O, and the disposable respirator filters at least 95% of airborne particles with a median aerodynamic diameter of 0.3 µm.

19. The method of claim 18, wherein forming the nonwoven web comprises calendering the nonwoven web to impart a smooth, lint-free surface.

20. The method of claim 18, wherein the nonwoven web has a basis weight of at least about 80 gsm and less than about 120 gsm and a thickness between 25 mils and 50 mils.

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