Apparatus and method for providing a pathogen-killing barrier between a first area and a second area

Abstract

A method is provided for forming a barrier configured to be disposed between a first region and a second region to prevent passage of pathogens between the first region and the second region. The method includes meltblowing a stream of polymeric fibers onto a surface to form a nonwoven fabric used to create the barrier. The meltblowing includes introducing a pathogen-killing component into the stream of polymeric fibers. A device of a system for forming a barrier according to the methods disclosed herein is also provided. The device is configured to introduce a pathogen-killing component into the stream of polymeric fibers downstream of an extruder and upstream of a collector.

Description

[Background technology]

[0001] It is commonly known that pathogens such as viruses and bacteria are easily transmitted between people through direct and indirect contact. An example of direct transmission is when aerosolization of a pathogen occurs during exhalation, coughing, or sneezing and is transmitted to another individual. Indirect transmission occurs when a pathogen comes into contact with and resides on an intervening surface such as a doorknob, a counter surface, a table surface, or an individual's hands. Summary of the Invention

[0002] Techniques are provided for providing a barrier disposed between a first region and a second region, treated with a pathogen-killing component, to kill or inactivate pathogens (e.g., viral particles) and thus prevent transmission of the pathogen between the first region and the second region.

[0003] The inventors have recognized that various conventional methods (e.g., meltblowing) are available that can be used to form a nonwoven fabric from a polymeric material that can be used as a barrier between a first region and a second region. However, the inventors have recognized that such conventional methods do not add a pathogen-killing component (e.g., salt crystals) to the nonwoven fabric, thus enhancing the prevention of pathogen transmission between the first region and the second region. The inventors have then realized that meltblowing methods can be used to form a nonwoven fabric, and then a pathogen-killing component (e.g., salt crystals) can be added to the nonwoven fabric using various means (e.g., immersing the nonwoven fabric in a salt solution for 24-36 hours). However, the inventors have recognized that such methods are time-consuming, as they require approximately 24-36 hours (e.g., for curing) to form a barrier with a pathogen-killing component. Therefore, the inventors have developed an improved method disclosed herein in which a pathogen-killing component is incorporated into the melt-blowing process such that the nonwoven fabric formed by the melt-blowing process already has the pathogen-killing component embedded therein. This eliminates the time-consuming step of adding the pathogen-killing component to the nonwoven fabric after the melt-blowing process (e.g., during a curing step that can last up to 24-36 hours). As a result, the improved melt-blowing process can result in the formation of a nonwoven fabric with an embedded pathogen-killing component in less than an hour, as opposed to 24-36 hours for a conventional melt-blowing process.

[0004] The inventors of the present invention have recognized that conventional masks are available that attempt to prevent the transmission of pathogens between two regions. In one example, conventional masks are available that provide an inner layer treated with a pathogen-killing component (e.g., a virucidal component) sandwiched between two outer layers that are not treated with a pathogen-killing component. The inner layers of these conventional masks are used to kill or inactivate pathogens, but the untreated outer layers of these masks become contaminated when pathogens come into contact with these outer layers. As a result, when a user touches or removes the mask, they can contaminate the user's hands and therefore subsequently contaminate themselves (e.g., by touching the face) or other surfaces (e.g., by touching these surfaces). In addition, the inventors of the present invention have recognized that discarding this contaminated mask can cause further contamination of other surfaces that come into contact with the outer layers during disposal. To overcome this shortcoming of conventional masks, the inventors of the present invention have developed an improved method, disclosed herein, for forming a barrier (e.g., a single layer barrier or a multi-layer barrier) treated with a pathogen-killing component that can be worn on the face as a face cover. The improved methods are used to form barriers that advantageously kill or inactivate incident pathogens and minimize the risk of contamination of the barrier. Thus, the improved barriers formed by the methods disclosed herein minimize the risk of contamination of the user (e.g., when touching or disposing of the barrier) and other surfaces (e.g., when the barrier is disposed of).

[0005] The inventors have recognized other shortcomings of conventional masks. For example, because conventional masks include multiple layers, the breathability and therefore breathing performance of these masks is significantly limited. This can pose health concerns for individuals suffering from respiratory diseases (e.g., asthma). In addition, this can significantly limit the breathing of athletes who may be required to wear such conventional masks during sporting activities (e.g., by laws and / or regulations governing viral pandemics). To overcome this significant shortcoming of conventional masks, the inventors of the present invention have developed improved methods disclosed herein for forming a barrier (e.g., a single layer barrier or a multi-layer barrier) treated with a pathogen-killing component that can be worn on the face. In some embodiments, the improved barrier formed by the improved methods disclosed herein includes only a single layer and therefore has significantly higher breathability and breathing performance than conventional masks while being at least as effective at killing or inactivating pathogens. However, the present invention is not limited to barriers formed from a single layer, and other embodiments include barriers formed from multiple layers.

[0006] The inventors have also recognized other shortcomings of conventional masks. For example, there is a well-known shortage of certain masks (e.g., N95) used by medical professionals during viral pandemics. This shortage is driven by the frequency with which these masks are discarded after a certain number of uses. Although there are certain methods that can be used to sterilize such masks after multiple uses, these sterilization methods can damage the mask material and thus affect the performance of these masks during reuse. To overcome this significant shortcoming of the shortage of certain masks, the inventors of the present invention have developed an improved method disclosed herein for forming a barrier treated with pathogen-killing components that can be used to encapsulate conventional masks (e.g., N95) to minimize contamination of the mask. This advantageously extends the lifespan of conventional masks, thus reducing the instances of conventional mask shortages. In addition, the barrier formed by the improved method disclosed herein also improves other methods (e.g., sterilization) that can affect the performance of conventional masks during reuse.

[0007] The inventors of the present invention have noted that attempts to reduce transmission include prior inventions of masks. However, a limitation of masks is that the outer surface (facing away from the user) and the inner surface (facing the user) are inherently contaminated, whether from the environment or from the user, and therefore pose a risk of infection if the individual does not remove and dispose of the mask correctly. This represents a risk to the user, as well as to others through indirect infection. Also, in pandemic situations, as a result of shortages of personal protective equipment, many individuals are forced to reuse protective masks and often do not have a reliable means to sterilize the masks for reuse. Furthermore, some methods of sterilization result in the destruction of the mask's fibers, thereby reducing its effectiveness in removing pathogens. When shortages occur, many individuals are forced to use simple cloth face coverings, which are not reliable in preventing airborne infection and still pose a risk of possible indirect infection when removed.

[0008] In one embodiment, the present invention provides an improved method for forming a cover for a mask, the mask having embedded therein pathogen-killing components (e.g., virucidal and / or germicidal components) to provide protection to both the exterior and interior surfaces of the mask, prevent / reduce contamination of the mask, thereby improving safety when reuse is required, and reducing the risk of second-hand infection when the cover is removed and discarded by inactivating or destroying pathogens. If a mask is not available for use, individuals may also choose to use the present invention to form a face covering and provide a measure of safety with embedded pathogen-killing and germicidal components.

[0009] The inventors of the present invention have also recognized situations other than face coverings where a barrier is insufficient or not provided to prevent pathogens from passing from a first area to a second area. For example, air filters (e.g., air conditioning systems or ventilation devices, etc.), clothing (e.g., clothing for medical professionals or any clothing worn by everyday people), and food storage (e.g., to prevent airborne pathogens from contaminating and / or spoiling food). The inventors recognized that with traditional food packaging (e.g., shipping or storage containers), there is no effective barrier to prevent pathogens from contacting the food, which results in contamination and / or spoilage of the food. Thus, in some embodiments, the inventors of the present invention have developed a barrier having a pathogen-killing component that is effective in preventing food contamination and / or spoilage by preventing pathogens from contacting food items enclosed by the barrier.

[0010] In a first set of embodiments, a method is provided for forming a barrier configured to be disposed between a first region and a second region to prevent passage of a pathogen between the first region and the second region. The method includes meltblowing a stream of polymeric fibers onto a surface to form a nonwoven fabric used to create the barrier. The meltblowing includes introducing a pathogen-killing component into the stream of polymeric fibers.

[0011] In a second set of embodiments, a system device for forming a barrier configured to be disposed between a first region and a second region to prevent passage of a pathogen between the first region and the second region is provided. The system includes an extruder configured to melt polymer pellets to form a pressurized molten polymer. The system further includes a metering pump configured to discharge a consistent flow of the pressurized molten polymer received from the extruder. The system further includes a spinneret configured to extrude polymer filament strands from holes defined by the spinneret based on the pressurized molten polymer received from the metering pump. The system further includes an air manifold configured to attenuate the polymer filament strands into a stream of polymer fibers directed onto a collector defining a surface to form a nonwoven fabric. The device is configured to introduce a pathogen-killing component into the stream of polymer fibers downstream of the extruder and upstream of the collector.

[0012] In a third set of embodiments, there is provided a barrier formed by a method according to the first set of embodiments, the barrier including a first surface oriented toward the first region and a second surface oriented toward the second region.

[0013] In a fourth set of embodiments, a face covering configured to be worn by a user is provided. The face covering includes one or more barriers formed by a method according to the first set of embodiments. The one or more barriers are configured to inactivate pathogens incident from an external environment of the user.

[0014] Further aspects, features, and advantages will be readily apparent from the following detailed description, which merely illustrates certain specific embodiments and implementations, including the best mode contemplated for carrying out the invention. Other embodiments are also capable of other and different features and advantages, and the several details of which can be modified in various obvious respects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and description should be regarded as illustrative in nature, and not as restrictive.

[0015] Embodiments are illustrated by way of example, and not limitation, in the figures of the accompanying drawings in which like reference numerals refer to similar elements and in which: [Brief description of the drawings]

[0016] [Figure 1A] FIG. 2 is a schematic diagram illustrating an example of a single barrier layer having a pathogen-killing component between a first region and a second region, according to one embodiment. [Figure 1B] FIG. 2 is a schematic diagram illustrating an example of a multi-layer barrier having a pathogen-killing component between a first region and a second region, according to one embodiment. [Figure 2A] 1C is an image showing an example of a perspective view of the barrier of FIG. 1A or FIG. 1B worn as a face covering, according to one embodiment. [Figure 2B] 1C is an image showing an example of a perspective view of the barrier of FIG. 1A or FIG. 1B worn as a face covering, according to one embodiment. [Figure 2C] 2C is an image showing an example of a cross-sectional view of the barrier of FIG. 2A taken along line 2C-2C. [Figure 2D] 2B is an image showing an example of a front view of the oval shaped face covering of FIG. 2A, according to one embodiment. [Figure 2E] 2B is an image showing an example of a front view of the face covering of FIG. 2A with an elastic fastener attached, according to one embodiment. [Figure 2F] 2B is an image showing an example of a front view of the face covering of FIG. 2A in an arcuate shape, according to one embodiment. [Figure 2G]2F is an image showing an example of a front view of an elastic fastener used to secure the face covering of FIG. 2F, according to one embodiment. [Figure 2H] 2F with elastic straps for attaching the face covering to the face, according to one embodiment. [Figure 3A] 1C is an image showing an example of a perspective view of a face covering including the barrier of FIG. 1A or FIG. 1B over a mask, according to one embodiment. [Figure 3B] 3B is an image showing an example of a cross-sectional view of the face covering of FIG. 3A taken along line 3B-3B. [Figure 3C] 1C is an image showing an example of a perspective view of a face covering including the barrier of FIG. 1A or FIG. 1B enclosing a mask, according to one embodiment. [Figure 3D] 3D is an image showing an example of a cross-sectional view of the face covering of FIG. 3C taken along line 3D-3D. [Figure 3E] 3D is an image showing an example of a front view of the barrier of FIG. 3C prior to encapsulating a mask, according to one embodiment. [Figure 3F] 3B is an image showing an example of a back view of the barrier of FIG. 3A prior to encapsulating a mask, according to one embodiment. [Figure 4A] 1C is an image showing an example of a schematic diagram of the barrier of FIG. 1A or FIG. 1B used as an air filter in an air conditioning system, according to one embodiment. [Figure 4B] 4B is an image showing an example of a schematic diagram of an air filter of the air conditioning system of FIG. 4A, according to one embodiment. [Diagram 5] 1C is an image showing an example of a schematic diagram of the barrier of FIG. 1A or FIG. 1B used to form a garment worn by a medical professional, according to one embodiment. [Figure 6] 1C is an image showing an example of a schematic diagram of the barrier of FIG. 1A or FIG. 1B used as a filter in a ventilation device, according to one embodiment. [Figure 7] 1C is a flow chart illustrating an example of a method for forming the barrier of FIG. 1A or FIG. 1B, according to one embodiment. [Figure 8A]1C is an image showing an example of a graph depicting the X-ray diffraction (XRD) intensity of the barrier of FIG. 1A or FIG. 1B, according to one embodiment. [Figure 8B] FIG. 8B is an image showing an example of different Miller indices used in the XRD depicted in the graph of FIG. 8A. [Figure 9A] 1 is an image showing an example of light scattering of particles downstream of a conventional mask, according to one embodiment. [Figure 9B] 1 is an image showing an example of light scattering of particles downstream of a conventional surgical mask, according to one embodiment. [Figure 9C] 2B is an image showing an example of light scattering of particles downstream of the barrier of the face covering of FIG. 2A, according to one embodiment. [Figure 10] 1C is an image showing an example of a graph depicting the viral filtration efficiency (VFE) of the barrier of FIG. 1A or FIG. 1B, according to one embodiment. [Figure 11] 1C is an image showing an example of a system for forming the barrier nonwoven of FIG. 1A or FIG. 1B, according to one embodiment. [Figure 12A] FIG. 1C is a schematic diagram illustrating an example of a system for forming the barrier of FIG. 1A or FIG. 1B, according to one embodiment. [Figure 12B] FIG. 1C is a schematic diagram illustrating an example of a system for forming the barrier of FIG. 1A or FIG. 1B, according to one embodiment. [Figure 12C] FIG. 1C is a schematic diagram illustrating an example of a system for forming the barrier of FIG. 1A or FIG. 1B, according to one embodiment. [Figure 12D] FIG. 1C is a schematic diagram illustrating an example of a system for forming the barrier of FIG. 1A or FIG. 1B, according to one embodiment. [Figure 12E] FIG. 1C is a schematic diagram illustrating an example of a system for forming the barrier of FIG. 1A or FIG. 1B, according to one embodiment. [Figure 12F] FIG. 12C is a schematic diagram illustrating an example of a hopper of the system of FIG. 12A or FIG. 12E, according to one embodiment. [Figure 12G] FIG. 12C is a schematic diagram illustrating an example of a hopper of the system of FIG. 12A or FIG. 12E, according to one embodiment. [Figure 12H]FIG. 12C is a schematic diagram illustrating an example of a hopper of the system of FIG. 12A or FIG. 12E, according to one embodiment. [Figure 12I] FIG. 12C is a schematic diagram illustrating an example of a hopper of the system of FIG. 12A or FIG. 12E, according to one embodiment. [Figure 12J] FIG. 12C is a schematic diagram illustrating an example of a hopper of the system of FIG. 12A or FIG. 12E, according to one embodiment. [Figure 13] 12 is an image showing an example of a nonwoven fabric having embedded pathogen-killing components formed by the system of FIG. 11, according to one embodiment. [Figure 14] 12 is a flow chart illustrating an example of a method for using the system of FIG. 11 to form the barrier of FIG. 1A or FIG. 1B, according to one embodiment. [Figure 15A] 1C is an image showing an example of a schematic diagram of the barrier of FIG. 1A or FIG. 1B used to package a food item, according to one embodiment. [Figure 15B] 1C is an image showing an example of a schematic diagram of the barrier of FIG. 1A or FIG. 1B used to package a food item, according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Methods and apparatuses are described for providing a barrier (e.g., a single layer barrier, a multi-layer barrier, etc.) treated with a pathogen-killing component between a first region and a second region to prevent the passage of pathogens between the first region and the second region. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to avoid unnecessarily obscuring the invention.

[0018] Some embodiments of the invention are described below in the context of a method for forming a barrier disposed between a first region and a second region to prevent the passage or transmission of pathogens between the first region and the second region. In one embodiment, the invention is described in the context of a meltblowing method for forming a barrier disposed between a first region and a second region. However, the invention is not limited in this context and includes barriers formed by the method including a single or multi-layer barrier having a pathogen-killing component disposed between the first region and the second region to prevent the passage or transmission of viral particles between the first region and the second region.

[0019] For purposes of this description, a "barrier" refers to one or more layers of material that have been treated with a pathogen-killing component (e.g., a virucidal or bactericidal component) and placed between a first area and a second area to prevent or reduce instances of pathogen transmission between the first area and the second area. In one example, a "barrier" refers to a monolayer of material that has been treated with a pathogen-killing component. In another example, a "barrier" refers to multiple layers of material (e.g., multiple monolayers laminated together) that have been treated with a pathogen-killing component. In yet another example, a "barrier" refers to multiple layers, where one or more layers are treated with a pathogen-killing component and one or more other layers are not treated with a pathogen-killing component. For purposes of this description, a "monolayer" refers to a single layer of material and excludes multiple layers of material or additional layers of different materials. For purposes of this description, a "pathogen-killing component" refers to any chemical or molecule that has the ability or tendency to destroy or inactivate pathogens, including, but not limited to, virucidal and bactericidal components. For purposes of this description, "virucidal component" means any chemical or molecule that has the ability or tendency to destroy or inactivate viruses. For purposes of this description, "germicidal component" means any chemical or molecule that has the ability or tendency to destroy or inactivate bacteria. For purposes of this description, "mask" means a traditional face mask (e.g., an N95 mask) that is worn to reduce instances of pathogen transmission and includes multiple layers of material. For purposes of this description, "face covering" means a covering worn over the face that includes a barrier as disclosed herein.

[0020] In one embodiment, the present invention provides a mask cover or face cover suitable for wearing that is treated with a compound designed to inhibit the passage of viruses and bacteria and to destroy viruses and bacteria. The cover allows the user to reuse the mask, whether it is a surgical mask, N95 mask, KN95 mask, P100 mask, or other mask that an individual may use, by reducing contamination of the mask. The present invention also reduces contamination of the user's environment upon disposal by treating with a compound designed to kill viruses and bacteria.

[0021] 1. Barrier structure and characteristics 1A is a schematic diagram illustrating an example of a barrier 100 disposed between a first region 102 and a second region 104. In one embodiment, pathogens 110 (e.g., virus particles in an aerosol droplet) are incident on the barrier 100 from the first region 102. In another embodiment, pathogens 111 (e.g., virus particles in an aerosol droplet) are incident on the barrier 100 from the second region 104. Although FIG. 1 depicts pathogens 110, 111 incident on the monolayer 101 from both regions 102, 104, in some embodiments, only one of the pathogens 110 or 111 from one of the regions 102 or 104 is incident on the monolayer 101.

[0022] Although FIG. 1A depicts the barrier 100 as being a single layer 101, in another embodiment, the barrier can include multiple layers (e.g., multiple single layers 101 laminated together). FIG. 1B is a schematic diagram illustrating an example of a multi-layer barrier 100' having a pathogen-killing component 112 between a first region 102 and a second region 104, according to one embodiment. In one embodiment, the barrier 100' includes multiple layers 101a, 101b, where each layer 101a, 101b is similar to layer 101 of FIG. 1A. In one embodiment, the multiple layers 101a, 101b are laminated together using any known means understood by one of ordinary skill in the art. Although FIG. 1B depicts an exemplary embodiment of the barrier 100' having two layers 101a, 101b, in another embodiment, the barrier 100' includes three or more layers. In addition, while FIG. 1B depicts an exemplary embodiment in which each layer 101a, 101b includes a pathogen-killing component 112, in another embodiment, the barrier 100' includes one or more layers that do not include the pathogen-killing component 112 (e.g., an inner layer between two outer layers 101a, 101b that include the pathogen-killing component 112).

[0023] In one embodiment, the barrier 100 includes a single layer 101 disposed between the first region 102 and the second region 104, and the barrier 100' includes multiple layers 101a, 101b disposed between the first region 102 and the second region 104. As shown in Figures 1A and 1B, in one embodiment, the barrier 100, 100' extends along the interface between the first region 102 and the second region 104 a distance sufficient to prevent passage of pathogens 110, 111 between the first region 102 and the second region 104. The distance that the barrier 100, 100' extends along the interface of the first region 102 and the second region 104 will depend on the specific arrangement and circumstances of the first region 102 and the second region 104. In some embodiments, the monolayer 101 includes only a single layer of material, excluding an additional layer disposed between the first region 102 and the second region 104. In another embodiment, the barrier 100' includes multiple layers 101a, 101b (e.g., multiple monolayers 101 laminated together) disposed between the first region 102 and the second region 104. In an exemplary embodiment, the barrier 100, 100' includes a woven or nonwoven layer of material, including one or more of microfibril fabric, tightly woven cotton fabric, absorbent cellulosic fiber layers, woven fabrics, textiles, polymer laid fabrics (e.g., spunbond and meltblown), dry and wet laid nonwoven fabrics, and the like. In an exemplary embodiment, polypropylene is a preferred material for the barrier 100, 100'. In an exemplary embodiment, the barrier 100, 100' includes pores in each layer 101 having a particular range of dimensions (e.g., about 4 microns, and / or in the range of about 3 microns to about 5 microns, and / or in the range of about 2 microns to about 6 microns).

[0024] In one embodiment, the barrier 100, 100' includes a pathogen-killing component 112 within each layer 101. In one embodiment, each layer 101 of the barrier 100, 100' is treated with the pathogen-killing component 112 using a method described below. In yet another embodiment, the pathogen-killing component is integrated or incorporated into the layer 101 of the barrier 100, 100' during the manufacturing process of the barrier 100, 100'. In one embodiment, the layer 101 of the barrier 100, 100' is treated with a single component or combination of components having virucidal and / or bactericidal properties. In an exemplary embodiment, these components include one or more of an acid, a salt, or an ester. In one exemplary embodiment, the components include citric acid, any carboxylic acid, or any mineral acid. In another exemplary embodiment, the component comprises one or more of citrate esters, vitamin C esters, pyruvates, citrates, isocitrates, ketoglutarates, succinates, fumarates, malates, oxaloacetates, or base components (e.g., soaps, sodium lauryl sulfate, quaternary ammonium salts; cationic, anionic, nonionic surfactants, or tallow amines, etc.). In an exemplary embodiment, the concentration of the acidic component may range from about 11% to about 100% of the acid, salt, or ester, and the concentration of the base component may range from about 0.1% to about 10% of the surfactant, salt, or ester. In yet another exemplary embodiment, other pathogen-killing components (e.g., virucidal and / or bactericidal components) that may be utilized include NaCl, disodium ethylenediaminetetraacetate, zinc, copper, nickel, iodine, manganese, tin, boron, or silver; salts thereof; chelating agents thereof; chelactants thereof; surfactant-binding compositions thereof; or ions thereof. In exemplary embodiments, metal virucidal compositions may range from about 1% to about 100% solutions, and colloids and phycocolloids may also be utilized.

[0025] In another embodiment, the barrier 100, 100' is treated with the pathogen-killing component 112 along the entire thickness of the barrier 100, 100' (e.g., the entire thickness of a single layer 101 in the barrier 100, or the entire thickness of each layer 101a, 101b of the multi-layer barrier 100'). The thickness is the dimension perpendicular to the interface between the regions 102, 104 and extending from the first region 102 to the second region 104. As shown in Figures 1A and 1B, in one exemplary embodiment, the barrier 100, 100' is treated with the pathogen-killing component 112 along the entire thickness of the barrier 100, 100' from the outer surface 108 of the first side 106 of the barrier 100, 100' to the outer surface 118 of the second side 116 of the barrier 100, 100'. If the barrier 100' is a multi-layer barrier, the barrier 100' is treated with the pathogen-killing component 112 along the entire thickness of the layers of the barrier 100' from the outer surface 108 of the top layer 101a of the multi-layer barrier to the outer surface 118 of the bottom layer 101b of the multi-layer barrier 100'. In an exemplary embodiment, the pathogen-killing component 112 comprises one or more of a salt, an acid, and an ester. Although Figures 1A and 1B are not drawn to scale and thus some of the layers 101, 101a, 101b do not include the pathogen-killing component 112, this is merely for ease of illustration, and in one embodiment, the pathogen-killing component 112 is provided along the length of each layer 101, 101a, 101b (e.g., uniformly disposed along the entire length) on the interface between the regions 102, 104.

[0026] In an exemplary embodiment, since virus particles typically impinge on the barrier 100, 100' in water droplets (e.g., aerosols), salt is effective as a virucidal component to kill and / or inactivate the virus particles. When a water droplet containing virus particles comes into contact with layer 101 of the barrier 100, 100', salt crystals in layer 101 dissolve into the water droplet. Over time, the water droplet evaporates, thus reducing the amount of water containing the virus particles and, consequently, increasing the relative salt concentration. When the salt concentration reaches a sufficient level, the salt inactivates and / or kills the virus particles.

[0027] In one embodiment, the first side 106 of the barrier 100, 100' is directed toward the first region 102. In an exemplary embodiment, the outer surface 108 of the first side 106 is coated with a pathogen-killing component 112 and directed toward the first region 102 such that pathogens 110 in the first region 102 are incident on the outer surface 108 of the first side 106. In another exemplary embodiment, the outer surface 108 of the first side 106 is the first surface encountered by pathogens 110 incident on the barrier 100, 100' (e.g., no other layers or surfaces or components of the barrier 100 interact with the pathogens 110 prior to the outer surface 108).

[0028] In one embodiment, the second side 116 of the barrier 100, 100' is directed toward the second region 104. In an exemplary embodiment, the outer surface 118 of the second side 108 is coated with the pathogen-killing component 112 and directed toward the second region 102 such that the pathogens 111 in the second region 104 are incident on the outer surface 118 of the second side 116. In another exemplary embodiment, the outer surface 118 of the second side 116 is the first surface encountered by the pathogens 111 incident on the second side 116 (e.g., no other layers or surfaces or components of the barrier 100 come into contact with the pathogens 111 prior to the outer surface 118). In an exemplary embodiment, the pathogen-killing component 112 coated on the outer surfaces 108, 118 of the first face 106 and the second face 116 is configured to inactivate pathogens 110, 111 (e.g., virus particles in an aerosol) that are incident on the outer surfaces 108, 118 of the first face 106 and the second face 116.

[0029] In one embodiment, the pathogen-killing component 112 comprises a salt having a level of crystallization across the thickness of the layer 101 of the barrier 100, 100' from the outer surface 108 of the first side 106 to the outer surface 118 of the second side 116. In one embodiment, the level of crystallization of the salt is measured based on X-ray diffraction (XRD) analysis, as described below in connection with Figures 8A and 8B.

[0030] In one embodiment, the barrier 100, 100' has a breathability greater than a breathability threshold. In one embodiment, the breathability is based on a value of an air pressure differential across the barrier 100, 100' (e.g., between the first surface 106 and the second surface 116) based on airflow through the barrier 100, 100' at a constant flow rate (e.g., about 8 L / min or in a range of about 4 L / min to about 12 L / min). In an exemplary embodiment, the breathability of the barrier 100, 100' is greater than a value of an air pressure differential of about 0.2 mm H20 / cm 2 In another exemplary embodiment, the air permeability is set to be less than 0.1 mm H20 / cm 2 It is designed to be less than.

[0031] In one embodiment, the barrier 100, 100' has a viral filtration efficiency between the first region 102 and the second region 104 that exceeds a threshold filtration efficiency (e.g., 85%). In one embodiment, the viral filtration efficiency of the barrier 100, 100' is at least 95% between the first region 102 and the second region 104.

[0032] In one embodiment, the barrier 100, 100' is used as a face covering. FIG. 2A is an image showing an example of a perspective view of the barrier 100, 100' of FIG. 1A or FIG. 1B worn as a face covering 200, according to one embodiment. In an exemplary embodiment, the face covering 200 includes a barrier 100, 100' having dimensions sufficient to cover the face (e.g., mouth and nose) of a user 203. In an exemplary embodiment, the height of the barrier 100, 100' ranges from about 10 cm and / or about 5 cm to about 20 cm, and / or the width of the barrier 100, 100' ranges from about 21 cm and / or about 15 cm to about 25 cm, and / or the thickness of the barrier 100, 100' ranges from about 3 mm and / or about 2 mm to about 4 mm and / or about 0.5 mm to about 5 mm. These ranges of numerical dimensions of the barrier 100, 100' are merely examples of ranges of these numerical dimensions, and thus the numerical dimensions may be selected outside of these ranges.

[0033] In this embodiment, the first region is the external environment 202 of a user 203 of the face covering 200. Thus, in this embodiment, the outer surface 108 of the first side 106 is directed toward the external environment 202 (see FIG. 2A). Also, in this embodiment, the second region 204 is the face of the user 203 (e.g., the region between the face of the user 203 and the face covering 200). In this embodiment, the face covering 200 includes a barrier 100, 100' for preventing the passage of pathogens 110 from the external environment 202 to the user 203 (e.g., to prevent contamination of the user 203 by the external environment 202) and / or for preventing the passage of pathogens 111 from the user 203 to the external environment 202 (e.g., to prevent contamination of the external environment 202 by the user 203).

[0034] In one embodiment, the face covering 200 is secured to the face of the user 203 using ear loops 206. However, embodiments of the present invention are not limited to this design. FIG. 2B is an image showing an example of a perspective view of the barrier 100, 100' of FIG. 1A or FIG. 1B worn as a face covering 200', according to one embodiment. In one embodiment, unlike the face covering 200 of FIG. 2A, which is attached to the face of the user 203 with the ear loops 206, the face covering 200' of FIG. 2B is attached to the face of the user 203 by sticking or adhering the face covering 200' directly to the face of the user 203 (e.g., without the use of the ear loops 206). In one exemplary embodiment, an adhesive 208 is provided on the outer surface 118 of the second side 116 such that the second side 116 is configured to be attached directly to the face of the user 203 with the adhesive 208. In an exemplary embodiment, the adhesive 208 is a mixture of isopropanol and partially hydrogenated rosin, for example, 80% and 20% by weight, respectively. In an exemplary embodiment, as shown in FIG. 2B, an adhesive 208 is provided along the perimeter of the outer surface 118 of the second side 116 such that the adhesive 208 is configured to form an airtight seal between the barrier 100, 100' and the user 203 when the second side 116 is attached directly to the face of the user 203. In an exemplary embodiment, the adhesive 208 is a strip having a width of about 1.5 cm and / or a width ranging from about 0.5 cm to about 2 cm along the perimeter. The present inventors have recognized that the face covering 200' offers distinct advantages over face coverings 200 with ear loops 206, such as reducing the risk of infection by preventing air from leaking around the edges of the barrier 100, 100' when the user 203 inhales (reducing infection of the user) or exhales (reducing infection of the external environment). Additionally, other distinct advantages of the face covering 200' include increased comfort and the elimination of the need to remove the ear loops 206 in certain situations (e.g., when cutting hair), as well as other advantages (e.g., less fogging of glasses).

[0035] FIG. 2C is an image showing an example of a cross-section of the barrier 100, 100' of FIG. 2A along line 2C-2C. In one embodiment, FIG. 2C also depicts a cross-section of the barrier 100, 100' of FIG. 2B. The cross-section of FIG. 2C is taken only along a portion of the height of the face covering 200 (e.g., between the top and bottom of the face covering 200 in contact with the user 203). As shown in FIG. 2C, in one embodiment, the second region 204 is disposed between the face of the user 203 and the outer surface 118 of the second side 116. In one embodiment, as shown in FIG. 2C, pathogens 210 are incident on the outer surface 108 of the face covering 200 from the external environment 202, and thus the pathogen-killing component 112 coated on the outer surface 108 is configured to kill and / or inactivate the incident pathogens 210. In one embodiment, as shown in FIG. 2C, pathogens 211 enter onto the outer surface 118 of the face covering 200 from the face of the user 203, and thus the pathogen-killing component 112 coated on the outer surface 118 is configured to kill and / or inactivate the entering pathogens 211.

[0036] In yet another embodiment, the face covering can be attached to the user 203 using fasteners (e.g., elastic straps) that secure around the head of the user 203. FIGS. 2D and 2E are images illustrating one example of a face covering 200″ configured to be secured to the face of the user 203 using fasteners (e.g., elastic straps 230). In one embodiment, as shown in FIG. 2D, the face covering 200″ is elliptical with a major radius 222 having a value of about 38 centimeters (cm) or in a range of about 30 cm to about 40 cm, and a minor radius 224 of about 20 cm and / or in a range of about 15 cm to about 25 cm.

[0037] In another embodiment, as shown in FIG. 2E, the face covering 200″ is circular in shape. In an embodiment, the elastic straps 230 are attached to two anchor points 232a, 232b of the face covering 200″. In an exemplary embodiment, the anchor points 232a, 232b are along the perimeter of the outer surface 118 that faces the user 203. In an exemplary embodiment, the length of the elastic straps 230 is adjustable so that the face covering 200″ can fit the area of ​​the user 203. In another embodiment, the face covering 200″ is secured to the user 203 by first placing the outer surface 118 adjacent to the face of the user 203 and then stretching the elastic straps 230 behind the user's 203 head to hold the face covering 200″ on the face of the user 203. Figures 2F-2H show further images illustrating an example of the barriers 100, 100' (Figure 2F) used to create the face covering 200'', the elastics 230 (Figure 2G) used to secure the face covering 200'' to the user 203, and the face covering 200'' with the elastics 230 attached (Figure 2H).

[0038] 2A-2H disclose the use of the barrier 100, 100' as a face covering, but embodiments of the present invention are not limited to this arrangement. In another embodiment, a face covering is provided that includes the use of the barrier 100, 100' in conjunction with a conventional mask (e.g., N95). In these embodiments, the barrier 100, 100' is used to reduce contamination of the conventional mask (e.g., by killing or inactivating incident pathogens on the mask), advantageously extending the life of the conventional mask.

[0039] In one embodiment, the barrier 100, 100' is used on the outside of the conventional mask (e.g., the side of the mask that faces the user's external environment). In an exemplary embodiment, the conventional mask 310 includes one or more untreated layers (e.g., not treated with a pathogen-killing component) and is therefore susceptible to surface contamination by pathogens. FIG. 3A is an image showing an example of a perspective view of a face covering 300 including the barrier 100, 100' of FIG. 1A or FIG. 1B over the mask 310, according to one embodiment. FIG. 3B is an image showing an example of a cross-sectional view of the face covering 301 of FIG. 3A along line 3B-3B. As shown in FIG. 3A, ear loops 306 are used to secure the conventional mask 310 to the face of the user 203. The barrier 100, 100' is positioned outside the conventional mask 310 (e.g., between the conventional mask 310 and the external environment 202) to prevent contamination of the conventional mask 310 by pathogens 210 incident on the mask 310 (e.g., by killing or inactivating viral particles in aerosol droplets). In this embodiment, the outer surface 108 of the first side 106 of the barrier 100, 100' is directed toward the external environment 202. As shown in FIG. 3B, the conventional mask 310 is positioned within the second region 304 (e.g., between the user 203 and the barrier 100, 100').

[0040] In another embodiment, the barrier 100, 100' is used to enclose a conventional mask (e.g., to cover both the side facing the external environment 202 and the side facing the user 203 when worn on the face). FIG. 3C is an image showing an example of a perspective view of a face covering 300' including the barrier 100, 100' of FIG. 1A or FIG. 1B enclosing a mask 310, according to one embodiment. FIG. 3D is an image showing an example of a cross-sectional view of the face covering 300' of FIG. 3C along line 3D-3D. Unlike the face covering 300 of FIG. 3A and FIG. 3B, the face covering 300' of FIG. 3C and FIG. 3D includes a barrier 100, 100' that covers both sides of the conventional mask 310 (e.g., the side of the conventional mask 310 facing the external environment 202 and the side of the conventional mask facing the user 203).

[0041] In yet another embodiment, the barrier 100, 100' encapsulates the conventional mask 310 (e.g., such that all surfaces of the conventional mask 310 are covered by the barrier 100, 100'). As shown in FIG. 3D, the barrier 100, 100' encapsulates the conventional mask 310 such that the outer surface 108' of the first side 106 is positioned to kill or inactivate pathogens 210 incident on the conventional mask 310 from the external environment 202, and the outer surface 118' of the second side 116 is positioned to kill or inactivate pathogens 211 incident on the conventional mask 310 from the user 203 (e.g., expelled from the mouth and / or aerosol droplets by sneezing, etc.). Thus, the barriers 100, 100' of FIG. 3D advantageously kill or inactivate pathogens 210, 211 incident on the conventional mask 310 from both regions 202, 304', thereby minimizing the risk of contamination of the conventional mask 310, and thus extending the life of the conventional mask 310.

[0042] In one embodiment, the barrier 100, 100' is a one-piece barrier such that the outer surface 108' and the outer surface 118' are part of the same single piece of material. In another embodiment, the outer surface 108' and the outer surface 118' are from separate pieces of the barrier 100, 100' and are therefore not one-piece. In an exemplary embodiment in which the outer surfaces 108', 118' are separate pieces of material, the outer surfaces 108', 118' are adhered (e.g., using an adhesive) to a conventional mask 310.

[0043] As discussed in connection with Figures 3C and 3D, in one embodiment, the barrier 100, 100' is a single piece of integral material that encapsulates the conventional mask 310. Figures 3E and 3F are images showing an example of a front and back view, respectively, of this monolayer 101' prior to encapsulating the mask 310. In one embodiment, Figures 3E and 3F depict the monolayer 101' of Figure 3D prior to encapsulating the conventional mask 310. In one embodiment, the monolayer 101' is folded around an edge (e.g., top edge) of the conventional mask 310, and fasteners are used to secure the monolayer 101' to itself around the opposite edge (e.g., bottom edge).

[0044] 3E depicts the outer surface 108' and the outer surface 118' of the barrier 100, 100' (e.g., monolayer 101) separated by creases 324 along which the monolayer 101 is folded to enclose the conventional mask 310. Additionally, in one embodiment, adhesive strips 330 are provided spaced along each side of the outer surface 108', 118' so that each side of the monolayer 101 can be adhered to the outside of the side of the conventional mask 310. Additionally, in one embodiment, a plurality of slits or openings 326a-326d are provided adjacent the four corners of the outer surface 118' through which the ear loops 306 of the conventional mask 310 are threaded prior to fastening behind the ears of the user 203. In yet another embodiment, a plurality of creases 320, 322 are provided along the outer surface 108', 108' with varying spacing (e.g., ranging from about 1.5 cm to about 4 cm) between the creases 320, 322 as shown. In one embodiment, the width of the outer surfaces 108', 118' is about 20 cm, or in the range of about 15 cm to about 25 cm. In another embodiment, the height of the single layer 101 is about 33 cm, or in the range of about 25 cm to about 40 cm.

[0045] FIG. 3F depicts inner surfaces 107' and 117' (FIG. 3D) of barrier 100, 100' (e.g., monolayer 101) that face the front and back, respectively, of enclosed conventional mask 310 when monolayer 101 is folded to enclose conventional mask 310. Also depicted in FIG. 3F are four openings 326a through 326d, in one embodiment, through which ear loops 306 are configured to extend. Adhesive 340 is provided along the perimeter of inner surfaces 107', 117' such that the edges of inner surfaces 107', 117' are self-adhesive when monolayer 101 is folded to enclose conventional mask 310.

[0046] Based on the previously disclosed embodiments, the barrier 100, 100' allows the user to reduce exposure to infectious pathogens. In one embodiment, the barrier 100, 100' is a pleated mask cover with flexibility similar to a surgical mask, which encases the user's mask 310 and provides a sealed environment with the aid of adhesives 330, 340 to prevent contamination of the mask, and is also flexible to conform to the user's face and provide a snug fit as required when using an N95 or similar mask / respirator. The mask cover has slits 326a to 326d that allow for the passage of straps when using a mask with this form factor similar to a surgical mask. In another embodiment, the mask cover also provides sealing protection when using a mask 310 with ear loops 306 or other methods used to fasten / secure to the user's head. In an exemplary embodiment, the flaps for the adhesive seal are designed to be peeled back to open the cover and remove the mask 310 without contaminating either the exterior or interior surface.

[0047] Although Figures 2A-2H and Figures 3A-3D discuss the barrier 100, 100' used in the context of a face covering, embodiments of the present invention are not limited to this use of the barrier 100, 100'. In another embodiment, the barrier 100, 100' is used in the context of an air filter for an air conditioning system. The barrier 100, 100' can be advantageously used to kill or inactivate pathogens present in the air circulated by the air conditioning system. Figure 4A is an image showing an example of a schematic diagram of the barrier 100, 100' of Figures 1A or 1B used as an air filter 404 in an air conditioning system 400, according to one embodiment. Figure 4B is an image showing an example of a schematic diagram of the air filter 404 of the air conditioning system 400 of Figure 4A, according to one embodiment.

[0048] In one embodiment, the air filter 404 includes the barrier 100, 100' discussed in connection with Figures 3D-3F, except that the barrier 100, 100' is sized and configured to encapsulate a conventional air filter 403 used in an air conditioning system 400 (rather than encapsulating a conventional mask 310). In one exemplary embodiment, the barrier 100, 100' is used to encapsulate an air filter 403 located in an air handling unit 402 of an air conditioning system, thus advantageously killing or inactivating pathogens in the air received through a return air duct 406. In this exemplary embodiment, the first region 102 is the living space and the second region 104 is the air handling unit 402. In another exemplary embodiment, the barrier 100, 100' is used to encapsulate an air filter 403 located at the outlet of a supply air duct 408 (to a room) (or attached to a vent or grate), thus advantageously killing or inactivating pathogens in the air before it is discharged into the living space. In this exemplary embodiment, first area 102 is an air supply duct 408 and second area 104 is a living space (eg, a room into which air from duct 408 is directed).

[0049] 4A and 4B depict an air filter 404 (with barrier 100, 100') used in an air handling unit 402 of an air handling system 400 and at the outlet of a supply air duct 408, while in some embodiments, the air filter 404 is used only in one of the air handling unit 402 or the supply air duct 408. In yet another embodiment, while FIG. 4B depicts the filter 404 including a barrier 100, 100' enclosing a conventional air filter 403, in another embodiment, the filter 404 is simply a barrier 100, 100' (e.g., fixed to an outer frame having dimensions approximately equal to a conventional filter slot in the air handling unit 402 or the dimensions of the supply air duct 408 at the outlet).

[0050] 4A and 4B depict the barrier 100, 100' used with an air filter for an air conditioning system 400 used in a home or office, in yet another embodiment, the barrier 100, 100' can be used in the air conditioning system of a vehicle (e.g., cabin cars, including but not limited to airplanes, trains, and automobiles). In these embodiments, the barrier 100, 100' can be used to encapsulate existing conventional air filters in the air conditioning systems of these vehicles, or can be placed adjacent to the outlet (or inlet) of the vehicle's air conditioning system (without a conventional air filter) to kill or inactivate pathogens in the air circulated within the air conditioning system.

[0051] Another situation in which the barrier 100, 100' may be used, in one embodiment, is to form a garment or clothing, particularly a garment or clothing used in areas where pathogens are present (e.g., a medical facility). In an exemplary embodiment, the barrier 100, 100' may be used to form a garment worn by a medical professional (e.g., a surgeon in an operating room). In this exemplary embodiment, the first region 102 is the external environment of the medical facility, and the second region 104 is the body of the medical professional (e.g., covered by the garment). FIG. 5 is an image showing an example of a schematic diagram of the barriers 100a-100d of FIG. 1A or the barriers 100a'-100d' of FIG. 1B used to form a garment 500 worn by a medical professional (e.g., a surgeon), according to one embodiment. In an exemplary embodiment, the barrier 100a, 100a' is used to form a head covering worn by the medical professional, and / or the barrier 100b, 100b' is used to form a face covering worn by the medical professional, and / or the barrier 100c, 100c' is used to form a gown worn by the medical professional, and / or the barrier 100d, 100d' is used to form a shoe cover worn by the medical professional. The inventors of the present invention have recognized that the use of a single layer to form one or more garments worn by the medical professional advantageously minimizes the risk of infection or contamination of the medical professional by the external environment (and of the external environment by the medical professional) without affecting the level of comfort of the medical professional due to the breathability of the barrier 100, 100'. In one embodiment, the garment 500 is not limited to any particular garment (e.g., a surgical gown) and includes an isolation gown (e.g., typically used in intensive care units (ICUs) and can be relatively thin with a single layer). In some exemplary embodiments, the surgical gown employs a multi-layer barrier 100' to ensure that certain performance parameters are met (eg, preventing the passage of liquid contamination).

[0052] Another situation in which the barrier 100, 100' may be used, in one embodiment, is for an air filter used in a ventilation device. Figure 6 is an image showing an example of a schematic diagram of the barrier 100, 100' of Figure 1A or 1B used as a filter 601 in a ventilation device 600, according to one embodiment. In this exemplary embodiment, the first area 102 is an air supply duct 602 that directs air to a patient, and the second area 104 is the patient. In yet another exemplary embodiment, the first area 102 is the patient, and the second area 104 is an air supply duct 604 that directs air from the patient to the ventilation device 600.

[0053] Another situation in which the barrier 100, 100' may be used, in one embodiment, is to protect food items from contamination and / or spoilage by pathogens. Figures 15A and 15B are images showing an example of a schematic of the barrier 100, 100' of Figure 1A or 1B used to package food items, according to one embodiment. In some embodiments, as shown in Figure 15A, a package 1500 is provided with the barrier 100, 100' that is used to enclose individually packaged food items 1504a, 1504b, 1504c (e.g., individually packaged fruit). In this embodiment, each barrier 100, 100' enclosing a respective food item 1504a, 1504b, 1504c prevents the passage of pathogen-killing components 112 (e.g., bacteria, viruses, etc.) from the first region 102 (e.g., the external environment of the food items 1504a, 1504b, 1504c) to the second region 104 (e.g., the area enclosed by the barrier 100, 100' in which the food items 1504a, 1504b, 1504c are located). In another embodiment, as shown in FIG. 15B, a package 1550 is provided with a barrier 100, 100' that is used to enclose a container 1502 for a food item 1506 (e.g., a shipping or storage container for the food item, such as a Ziploc® bag or Tupperware® container, etc.). 15B, in some embodiments, the container 1502 has gaps 1508a, 1508b through which air passes to contact the food items 1506 due to structural limitations of the container 1502. As shown in FIG 15B, a barrier 100, 100' is used to enclose the container 1502, thus advantageously preventing the passage of pathogen-killing components 112 (e.g., bacteria, viruses, etc.) through the gaps 1508a, 1508b that could contaminate or spoil the food items 1506.

[0054] 2. The first method for forming a barrier Methods for forming the barrier 100, 100' are now presented herein. Figure 7 is a flow chart illustrating an example of a method 700 for forming the barrier 100, 100' of Figure 1, according to one embodiment. Although the steps are depicted in Figure 7 as essential steps in a particular order for purposes of explanation, in alternative embodiments, one or more steps, or portions thereof, may be performed in a different order, or overlap in time, sequentially or in parallel, or may be omitted, or one or more additional steps may be added, or the method may be modified in any combination.

[0055] In one embodiment, the method 700 is configured to form the material of the barrier 100, 100' to optimize one or more design parameters of the barrier 100, 100'. In one embodiment, one of the design parameters is the efficiency of the pathogen-killing component 112 in killing or inactivating pathogens. The inventors have recognized that this efficiency is based on the concentration of the pathogen-killing component 112 used in forming the barrier 100, 100'. In an exemplary embodiment where a salt is employed as the virucidal component 112, this efficiency is based on the level of crystallization (LOC) of the salt. Another design parameter is the breathability of the barrier 100, 100', which affects the comfort (e.g., breathability) of a user wearing a face covering including the barrier 100, 100'. Thus, in one embodiment, the method 700 is configured to optimize these two parameters (e.g., pathogen killing or inactivation efficiency and breathability) of the barrier 100, 100'. The inventors of the present invention have realized that varying one of the parameters may affect the other parameters. In an exemplary embodiment, the inventors of the present invention have realized that increasing the level of concentration of the pathogen-killing component 112 (or the level of salt crystallization) may decrease the breathability (and thus the breathability) of a face covering employing the barrier 100, 100'. Thus, in an exemplary embodiment, the method 700 is employed to optimize the values ​​of these parameters in order to design a barrier 100, 100' having a concentration of the pathogen-killing component 112 sufficient to efficiently kill or inactivate pathogens while simultaneously ensuring adequate breathability (and thus the breathability).

[0056] In one embodiment, one or more sheets of material are used to form the barrier 100, 100' (e.g., having a width and length of about 40 cm by 40 cm, and / or a width and length in the range of about 10 cm to about 50 cm, respectively). In one exemplary embodiment, the sheets of material are a thermoplastic material (e.g., polypropylene) and / or a cotton blend (e.g., silk, wool, men's, etc.).

[0057] In one embodiment, step 701 includes wetting the material with a solution that includes a pathogen-killing component having a concentration of a particular value. In one embodiment, the wetting of step 701 occurs for a first period of time (e.g., about 20 hours). In an exemplary embodiment, the solution includes a salt concentration (e.g., about 0.02 ml / cm 2 to about 0.06 ml / cm 2 and / or about 0.01 ml / cm 2 to about 0.1 ml / cm 2 (salts in the range of

[0058] In another embodiment, step 701 includes applying a pathogen-killing component (e.g., a virucidal and / or bactericidal component) to the material, including one or more of misting, spraying, sputtering, painting, or dipping / immersing (e.g., for liquid components), and pelleting or powdering (e.g., for solid components), applied in a dry coat, rolled, air dispersed, dry sputtered, evaporated, vacuum consolidated. In an exemplary embodiment, dry powders may be ground into nanoparticles or suspended and emulsified in liquids for application in coating mask covers. Gels and oils may be applied as liquid coatings.

[0059] In one embodiment, step 701 involves immersing the material in a tank of solution for a first period of time such that the material is completely immersed, and / or spraying the solution evenly onto the material, and / or injecting the solution into the material from a pourable platform. In an exemplary embodiment, step 701 involves immersing the material in a tank with a volume (e.g., about 34 mL) of solution for a first period of time (e.g., about 12 hours) to change the hydrophobic properties and increase wetting / absorption, which is considered a pre-wetting process. In this exemplary embodiment, the remaining volume (e.g., about 68 mL) is applied in the same manner before drying step 703. In another exemplary embodiment, the material is completely immersed in the tank of solution during wetting step 701. It should be noted that the specific values ​​of the above-mentioned parameters of immersion (e.g., duration of step 701, size of the material, volume of solution, etc.) can be adjusted based on the purpose of the material (e.g., face covering, air filter, clothing / apparel, food packaging, etc.).

[0060] In one embodiment, step 701 includes spraying the material placed in a Petri dish or plate of the required size (e.g., about 40 cm x 40 cm). In this embodiment, for all intents and purposes, the spraying step is performed using jet spraying or mist spraying, and the solution is spread evenly on the material. In an exemplary embodiment, the first period is about the same as the soaking step (e.g., about 12 hours). In an exemplary embodiment, the volume of the spray solution utilized in the spraying step is about 0.90 mL. In another exemplary embodiment, the spray diameter used during the spraying step is about 15.5 cm when placed about 20 cm away from the material. It is noted that the specific values ​​of the parameters of spraying mentioned above (e.g., the period of step 701, the size of the material, the volume of the solution, the volume of the spray, etc.) can be adjusted based on the purpose of the material (e.g., face covering, air filter, clothing / apparel, food packaging, etc.). It should be noted that the specific values ​​of the spray parameters described above (e.g., duration of step 701, size of material, volume of spray, diameter of spray, etc.) can be adjusted based on the purpose of the material (e.g., face covering, air filter, clothing / apparel, food packaging, etc.).

[0061] In one embodiment, step 701 includes injecting the material with the solution. In this embodiment, the injection is performed using an injectable platform and a syringe needle having a gauge in a particular range (e.g., about gauge 28 to about gauge 32 with an inner diameter in the range of about 0.18 mm to about 0.11 mm). In an exemplary embodiment, the effective wetting area is about 2.7 mm. In another embodiment, the needle is positioned on a platform with a width equal to the sheet of material (e.g., about 40 cm). In an exemplary embodiment, the solution is divided evenly to penetrate, inject, and impregnate the material immediately without a pre-wetting time. In an exemplary embodiment, step 701 includes about 22,500 syringes, each delivering about 0.004 mL in one step, thus eliminating the need for a pre-wetting step. In another exemplary embodiment, the volume is far in excess of the dead volume of a needle of that size, allowing optimal priming of each syringe.

[0062] In one embodiment, step 703 includes drying the wet material from step 701 for a second period of time after the first period of time (e.g., about 10 hours, or in a range of about 8 hours to about 15 hours). In one embodiment, step 703 is performed in one of an oven or an airtight container, and the second period of the drying step in the airtight container is shorter than the second period of the drying step in the oven. In an exemplary embodiment, in step 703, drying may be performed at a temperature in a range of about 20° C. to about 100° C., and sterilization may be performed by either heat (e.g., about 20° C. to about 100° C.) or gas sterilization.

[0063] In one embodiment, drying step 703 involves conventional drying, where the material is placed in a conventional oven at a uniform temperature and transported throughout by a rear fan. In this embodiment, drying step 703 takes place for about 24 hours. In another embodiment, drying step 703 involves vacuum drying, which takes place in an airtight container, dramatically reducing the relative humidity and pressure. In this exemplary embodiment, the atmospheric pressure is lowered, allowing the material to dry much more quickly. In the exemplary embodiment, the boiling point of water is significantly lowered (e.g., from about 100° C. to about 35° C.), resulting in an increased evaporation rate, allowing drying that would take 24 hours at atmospheric pressure to occur within a few hours, depending on the particular set of conditions.

[0064] In one embodiment, step 705 includes measuring the air permeability of the material after step 703. In one embodiment, measuring the air permeability includes measuring an air pressure differential across the material after step 703 based on a constant flow rate across the material.

[0065] In one embodiment, step 707 includes comparing the air permeability value measured in step 705 to a threshold air permeability value (e.g., 0.2 mm H20 / cm 2 If the breathability measurement from step 705 is greater than the threshold, method 700 moves to block 709. If the breathability measurement from step 705 is not greater than the threshold, method 700 moves to block 711.

[0066] In one embodiment, step 709 involves increasing the concentration of the pathogen-killing component 112 in the solution (e.g., increasing the concentration of salt in the solution) and then repeating steps 701 to 707 for the increased concentration value of the solution.

[0067] In one embodiment, step 711 includes using material from a previous iteration of step 703 as the barrier 100, 100'. In one embodiment, if a multiple layer 101a, 101b barrier 100' is used in step 711, the method 700 (e.g., steps 701 through 709) is repeated to form each respective layer 101a, 101b of the multi-layer barrier 100' that is subsequently used in step 711. In one embodiment, steps 701 through 707 are repeated if the measured air permeability is greater than the air permeability threshold. If step 707 indicates that the air permeability value is less than the air permeability threshold, this indicates that the concentration of the pathogen-killing component 112 is too high, adversely affecting the air permeability. Thus, the concentration of the pathogen-killing component 112 in the previous iteration of steps 701 through 707 is utilized in step 711 to form the barrier 100, 100'. In an exemplary embodiment, if the fourth iteration of steps 701 to 707 indicates that the measured air permeability is below the threshold, the concentration value used in the third iteration of steps 701 to 707 is employed in step 711 to form the barrier 100, 100'. This concentration of the pathogen-killing component 112 advantageously provides a useful balance between a high concentration of the pathogen-killing component 112 (e.g., to maximize pathogen killing or inactivation) while still ensuring an acceptable level of air permeability. The present inventors have found a surprising result - despite four iterations of steps 701 to 709 and four consecutive increases in the salt concentration in the solution, the measured air permeability exceeded the threshold in step 707 for each iteration. This is a surprising result, as the inventors would have expected that an increase in the salt concentration in the solution would decrease the air permeability (e.g., an increase in the concentration of salt crystals would be expected to partially cover some of the pores). Thus, in one embodiment, we performed method 700 and utilized the highest concentration value among four successive increments (four iterations of steps 701 to 709). In one exemplary embodiment, we increased the salt concentration value used during the four iterations of steps 701 to 709. In an exemplary embodiment, these incremented concentration values ​​for each iteration of steps 701 to 709 were 0.02122 ml / cm 2, 0.03182ml / cm 2 , 0.04244ml / cm 2 , and 0.06367 ml / cm 2 However, these exemplary values ​​of salt concentration are merely example values, and the salt concentration values ​​employed in the methods herein are not limited to these specific values ​​or these specific ranges of values.

[0068] The treated material with virucidal components (from steps 701 through 703) has certain properties and characteristics. In one embodiment, application of the solution to a polypropylene sheet (step 701) causes the material to exhibit certain properties and characteristics that are dramatically different than the bare sheets utilized in current conventional masks 310 (e.g., conventional surgical masks). The contact angle (Θ C ) is defined as the quantitative ability of a liquid to wet a solid surface. The presence of surfactants, in addition to the formation of salt crystals (e.g., NaCl crystals) on a material (e.g., polypropylene fiber), can change the surface properties to hydrophobic (e.g., Θ C 134±5°) to hydrophilic (e.g., Θ C The result is a significant improvement in the adhesion of viral aerosols to the fabric.

[0069] In one embodiment, when the outer surface 108, 118 of the barrier 100, 100' formed by the method 700 is exposed to a viral aerosol during use, the salt crystals at the contact points dissolve, gradually increasing the osmotic pressure within the viral cells. In this embodiment, evaporation occurs, shifting the salt concentration from the higher concentration of the barrier 100, 100' into the virus, eventually resulting in supersaturation of the cells. Once the solubility limit is reached, recrystallization of the salt begins. During drying, the virus and bacterial cells are exposed to even higher osmotic pressures, eventually reaching a high osmotic stress (e.g., about >541 mOsm). The combination of crystallization and intercellular stress promotes an irreversible deformation of the viral envelope and overall structural damage that causes the virus to lose infectivity.

[0070] 3. The second method for forming a barrier Unlike the first method 700 for forming a barrier 100, 100' disclosed in Figure 7, in which one or more sheets of material are formed before the pathogen-killing component (e.g., salt) is added to the material, in another embodiment, a second method is provided in which the pathogen-killing component is incorporated or integrated into one or more sheets of material (e.g., polymeric nonwovens) as the sheets of material are formed. The present inventors have recognized that the second method offers significant advantages, such as a significantly shorter time (e.g., less than an hour) to form a barrier 100, 100' having a pathogen-killing component 112.

[0071] We now discuss systems used to carry out the second method. Figure 11 is an image showing an example of a system 1100 for forming the nonwoven fabric of the barrier 100, 100' of Figure 1A or Figure 1B, according to one embodiment. In some embodiments, the system 1100 is used to form the barrier 100, 100' using meltblowing, and each layer 101 of the barrier 100, 100' is integrated or integrated with the pathogen-killing component 112 as each layer 101 is formed (e.g., layer 101 of the barrier 100, or layers 101a, 101b of the barrier 100'). However, in other embodiments, the system can be used to form the barrier 100, 100' and incorporate / integrate the pathogen-killing component 112 into the barrier 100, 100' using a method other than meltblowing.

[0072] In one embodiment, the method disclosed herein includes meltblowing. Meltblowing is a conventional manufacturing method for microfibers and nanofibers in which a polymer melt is extruded through a small nozzle surrounded by high-velocity blowing gas. The randomly deposited fibers form a nonwoven sheet product that can be applied in filtration, adsorbents, clothing, and drug delivery systems. The substantial advantages of meltblowing are simplicity, high specific productivity, and solvent-free operation. Some of the polymers used to manufacture meltblown fabrics include polypropylene, polystyrene, polyester, polyurethane, polyamide (nylon), polyethylene, polycarbonate, polylactic acid (PLA), to name a few. Meltblown nonwoven fabrics are porous. As a result, they can filter liquids and gases. These applications include water treatment, masks, and air conditioning filters. Nonwoven materials can hold several times their own weight in liquid. Meltblown fabrics have three attributes that help make them useful for clothing, particularly in harsh environments: thermal insulation, relative moisture resistance, and breathability. The present inventors have recognized that an improved meltblown process can be used with an additional step of introducing a pathogen-killing component 112 (e.g., salt) into the polymeric material (e.g., within the air stream utilized in the meltblown process) so as to incorporate it at the time of manufacture and eliminate the need for a secondary process of adding a salt solution to the finished fabric and then drying the fabric to form a crystalline structure within the fabric. This formed fabric is then used to form one or more layers 101 of the barrier 100, 100'.

[0073] 11, in one embodiment, the system 1100 includes an extruder 1102. In these embodiments, polymer pellets 1120 or granules are fed into the extruder 1102. The polymer pellets 1120 are conveyed along the extruder 1102, which has a heated surface such that the polymer pellets 1120 melt. The molten polymer material is then pressurized such that the extruder 1102 outputs a pressurized molten polymer 1122.

[0074] In one embodiment, the system 1100 also includes a gear pump 1104 that receives pressurized molten polymer 1122 from the extruder 1102. The gear pump 1104 then delivers a consistent flow of pressurized molten polymer 1124.

[0075] In one embodiment, the system 1100 also includes a die assembly 1106 that receives a consistent flow of pressurized molten polymer 1124 from the gear pump 1104. In one embodiment, the die assembly 1106 extrudes polymer filament strands through holes in a spinneret (not shown) of the die assembly 1106 based on the pressurized molten polymer 1122 received from the gear pump 1104.

[0076] In one embodiment, the system 1100 also includes an air manifold 1108 (e.g., an air compressor) to provide a flow of air to attenuate the polymer filament strands output from the die assembly 1106 into a stream of polymer fibers 1128. In one exemplary embodiment, the flow of air is a primary air flow 1126 that is directed into the die assembly 1106 (e.g., into a slot defined by the die assembly 1106) at a high velocity, where the primary air flow 1126 then attenuates the polymer filament strands into a stream of polymer fibers 1128. In another exemplary embodiment, the flow of air is a secondary air flow 1127 that is directed downstream of the exit of the die assembly 1106 at a low velocity (e.g., a lower velocity than the primary air flow 1126) where the secondary air flow 1128 attenuates the polymer filament strands into a stream of polymer fibers 1128. In some embodiments, both the primary air flow 1126 and the secondary air flow 1127 are employed to attenuate the polymer filament strands into a stream of polymer fibers 1128.

[0077] In one embodiment, the system 1100 also includes a collector 1110 (or conveyor) having a surface onto which a stream of polymeric fibers 1128 is directed to form a nonwoven fabric (not shown). In one embodiment, the nonwoven fabric is used to form the layer 101 of the barrier 100 or the multiple layers 101a, 101b of the barrier 100'. In one embodiment, the stream of polymeric fibers 1128 is directed across a width 1129 of the collector 1110 such that the nonwoven fabric formed on the collector 1110 has a width 1129. In an exemplary embodiment, the width 1129 varies based on the system 1100 and / or parameters of the system 1100 (e.g., the separation between the die assembly 1106 and the collector 1110).

[0078] In one embodiment, the system 1100 includes a device configured to introduce the pathogen-killing component 112 into the polymeric material at one or more locations along the system 1100. In one embodiment, the device is a pathogen-killing component source 1105 configured to introduce the pathogen-killing component 112 into one or both of the primary air stream 1126 or the secondary air stream 1127 such that the pathogen-killing component 112 is introduced into the stream of polymeric fibers 1128 upstream of the collector 1110. In another embodiment, the pathogen-killing component source 1105 is configured to introduce the pathogen-killing component 112 at a location further upstream in the system 1100, such as into the coherent stream of pressurized molten polymer 1124 (e.g., at or downstream of the gear pump 1104) or into the pressurized molten polymer 1122 (e.g., at or downstream of the extruder 1102). In these embodiments, the pathogen-killing component source 1105 is configured to introduce the pathogen-killing component 112 into the system such that the polymeric material is sufficiently malleable for the pathogen-killing component 112 to adhere to the polymeric material. In exemplary embodiments where the pathogen-killing component source 1105 is configured to introduce the pathogen-killing component 112 into the primary air stream 1126 or the secondary air stream 1127, the stream of polymeric fibers 1128 is sufficiently malleable for the pathogen-killing component 112 to adhere to the stream of polymeric fibers 1128. The inventors have recognized that this feature of the method is advantageous because it ensures that the nonwoven formed on the collector 1110 features a nonwoven of polymeric fibers having the pathogen-killing component 112 embedded or integrated therein (which can later be used to form one or more layers 101 of the barrier 100, 100'). Thus, the inventors of the present invention have recognized that this advantageous step eliminates the need to first form a nonwoven fabric, followed by a separate, time-consuming step of coating the formed nonwoven fabric with the pathogen-killing component 112.

[0079] In one embodiment, the system 1100 includes a winder 1112 that is used to collect (e.g., wind) the nonwoven fabric formed on the collector 1110 having the integrated or embedded pathogen-killing component 112. In an exemplary embodiment, the winder 1112 is rotatable to form a spool of nonwoven fabric that can later be used to form the various layers 101 of the barriers 100, 100' disclosed above (e.g., face coverings, air filters, PPE equipment, clothing or gowning materials for medical professionals, food packaging, etc.).

[0080] Figures 12A-12E are schematic diagrams illustrating an example of a system 1200 for forming the barrier 100, 100' of Figure 1A or 1B, according to one embodiment. System 1200 is similar to system 1100 of Figure 11, except for the features discussed herein.

[0081] In one embodiment, the system 1200 includes an extruder 1102 having an inlet 1201 where polymer pellets 1120 are gravity-fed into a heated barrel 1204 that houses a screw 1202. The screw 1202 rotates within the heated barrel 1204. The pellets 1120 are conveyed forward along the hot wall of the barrel 1204 between the flights of the screw 1202, as shown in FIG. 12A. As the polymer pellets 1120 move along the barrel 1204, they melt due to the heat and friction of the viscous flow and the mechanical action between the screw 1202 and the barrel 1204. In an exemplary embodiment, the screw 1202 is divided into a feed zone, a transition zone, and a metering zone. The feed zone preheats the polymer pellets 1120 in a deep screw channel and conveys them to the transition zone. The transition zone has channels of decreasing depth to compress and homogenize the molten polymer. The molten polymer is discharged into the metering zone, which serves to generate maximum pressure for extrusion. The pressure of the molten polymer is highest at this point and is controlled by a breaker plate (not shown) with a screen pack located near the screw discharge. The screen pack and breaker plate also filter out dirt and permeated polymer chunks. The pressurized molten polymer 1122 is then conveyed to the gear pump 1104.

[0082] In one embodiment, the system 1200 includes a gear pump (or metering pump) 1104, which is a positive displacement constant volume device for uniform melt delivery to the die assembly 1106. In one embodiment, the gear pump 1104 ensures a consistent flow of clean polymer mixture under process variations in viscosity, pressure, and temperature. The gear pump 1104 also provides polymer metering and the necessary process pressure. As shown in FIG. 12B, in one embodiment, the metering gear pump 1104 has two intermeshing counter rotating gears 1210a, 1210b. In these embodiments, the positive displacement is achieved by filling each tooth with polymer at the pump intake side 1212 and conveying the surrounding polymer to the pump discharge 1214, as shown in FIG. 12B. The pressurized molten polymer 1122 is output from the gear pump 1104 as a consistent flow of pressurized molten polymer 1124. In some embodiments, a consistent flow of pressurized molten polymer 1124 reaches a feed distribution system to provide a uniform flow to the spinnerets of the die assembly 1106 (or fiber forming assembly).

[0083] In one embodiment, the system 1200 includes a die assembly 1106 having one or more separate components. In one embodiment, these separate components include a polymer feed distribution (not shown), a spinneret 1220 (FIGS. 12C-12E), and one or more air manifolds 1108a, 1108b (FIG. 12A).

[0084] In one embodiment, the feed distribution section (not shown) of the die assembly 1106 typically does not have mechanical adjustments to compensate for variations in polymer flow across the width of the die assembly 1106. In another embodiment, the system 1200 often operates in a temperature range where thermal breakdown of the polymer proceeds rapidly. Thus, in some embodiments, the feed distribution section is typically designed such that the polymer distribution is less dependent on the shear properties of the polymer. This feature allows for meltblowing of widely different polymer materials with one distribution system. The feed distribution section balances both flow and residence time across the width of the die assembly 1106. In one embodiment, there are two types of feed distribution sections employed in the meltblowing die assembly 1106: T-type (e.g., tapered and non-tapered) and coat hanger type. In some embodiments, the coat hanger type feed distribution section is commonly used because it provides both uniform polymer flow and uniform residence time across the entire width of the die assembly 1106.

[0085] As shown in FIG. 12E, the feed distribution channel directs a consistent flow of pressurized molten polymer 1124 directly to the spinneret 1220 of the die assembly 1106. Web uniformity (e.g., of the formed nonwoven fabric on the collector 1110 across the width 1129 of FIG. 12A) is highly dependent on the design and manufacture of the spinneret 1220. As shown in FIG. 12E, in one embodiment, the die assembly 1106 includes a spinneret 1220 positioned within the die nose piece 1230 such that slots 1235a, 1235b are formed between the spinneret 1220 and the die nose piece 1230. In these embodiments, the spinneret 1220 for the meltblowing process uses tight tolerances, which makes it very expensive to manufacture. The spinneret 1220 is a wide, hollow, tapered piece of metal with hundreds of orifices or holes across its width. The polymer melt is extruded through these holes to form filament strands that are subsequently attenuated by hot air (eg, primary air stream 1126) to form a stream of polymer fibers 1128.

[0086] In some embodiments, smaller orifices are typically employed in the spinneret 1220 compared to those typically used in either fiber spinning or spunbond processes. In one embodiment, the spinneret 1220 has orifices of about 0.4 mm diameter spaced about 1 to 4 per millimeter (e.g., about 25 to 100 per inch). In an exemplary embodiment, two types of spinnerets are used: a capillary-type spinneret 1220 (FIG. 12C) and a drilled-hole spinneret 1220' (FIG. 12D). In the capillary-type spinneret 1220, the individual orifices are actually slots milled into a flat surface that then match identical slots milled into the mating surface. The two halves are then brought together and carefully aligned to form an array of openings or holes as shown in FIG. 12C. By using the capillary-type spinneret 1220, the problems associated with precisely drilling very small holes are avoided. In addition, the capillaries can be precisely aligned so that the holes follow a precise straight line. The drilled-hole spinneret 1220' has very small holes drilled by mechanical drilling or electrical discharge machining (EDM) into a single block of metal, as shown in FIG. 12D. During processing, the entire die assembly 1106 is heated in sections using external heaters to achieve the desired processing temperature. To produce a uniform web (e.g., a uniform nonwoven fabric across the width 1129 of the collector 1110 in FIG. 12A), it is important to closely monitor the die temperature. In some embodiments, the temperature of the die assembly 1106 ranges from about 215° C. to 340° C.

[0087] In one embodiment, the air manifold 1108 provides high velocity primary air stream 1126 through slots 1235a on the top and slots 1235b on the bottom side of the spinneret 1220, as shown in FIG. 12E. In this embodiment, the high velocity primary air stream 1126 is generated using an air compressor (not shown). In an exemplary embodiment, the compressed air stream 1126 passes through a heat exchange unit (not shown), such as an electric or gas heated furnace, to heat the air to the desired processing temperature. The primary air stream 1126 then exits the top and bottom sides of the spinneret 1220 through a narrow gap, as shown in FIG. 12E. In one exemplary embodiment, the air temperature of the primary air stream 1126 varies within a range of about 230° C. to about 360° C. In another exemplary embodiment, the velocity of the primary air stream 1126 varies from about 0.5 to about 0.8 times the speed of sound.

[0088] As soon as the molten polymer is extruded from the holes of the spinneret 1220, a high velocity primary air stream 1126 (exiting from the top and bottom sides of the spinneret 1220) attenuates the polymer stream to form a stream of polymer fibers 1128 (e.g., microfibers). In one embodiment, the pathogen-killing component 112 (e.g., salt crystals) is added to the primary air stream 1126 from a pathogen-killing component source 1105 (e.g., salt hopper 1205). Thus, by adding the pathogen-killing component 112 to the primary air stream 1126, the pathogen-killing component 112 adheres to the stream of polymer fibers 1128 that are heated and malleable based on the primary air stream 1126. The inventors of the present invention have recognized that this advantageously adheres the pathogen-killing component 112 (e.g., salt crystals) to the stream of polymer fibers 1128 upstream of the collector 1110. In the exemplary embodiment, vacuum devices 1240a, 1240b are provided to collect pathogen-killing components 112 that, in some embodiments, were added to the primary air stream 1126 but did not adhere to the stream of polymeric fibers 1128. The vacuum devices 1240a, 1240b advantageously return these pathogen-killing components 112 to the pathogen-killing component source 1105 (e.g., salt hoppers 1205a, 1205b) to increase the cost efficiency of the systems 1100, 1200. Figures 12F-12J are schematic diagrams illustrating an example of various views of the hopper 1205' of the system of Figure 12A or Figure 12E, according to one embodiment.

[0089] 12A depicts that in one embodiment, the pathogen-killing component source 1105 is a hopper 1205, while in another embodiment, the pathogen-killing component source 1105 includes an inverted manifold having an inlet pipe with a first diameter and branching into multiple outlet pipes with a second diameter smaller than the first diameter. The present inventors have recognized that such an inverted manifold can be used where the pathogen-killing component 112 is fed from the pathogen-killing component source 1105 into the inlet pipe, and then the outlet pipe distributes the output of the pathogen-killing component 112 along the width of the stream of polymeric fibers 1128 (e.g., the outlet pipe may distribute the pathogen-killing component 112 evenly across the width of the primary airflow 1126 directed at the stream of polymeric fibers 1128). This advantageously distributes the pathogen-killing component 112 more evenly across the width 1129 of the collector 1110 on which the nonwoven fabric 1130 is formed, thus assisting in even distribution of the embedded pathogen-killing component 112 across the width 1129 of the nonwoven fabric 1130. In these embodiments, the number of the multiple outlet pipes, the first diameter value, and / or the second diameter value are selected such that the pathogen-killing component 112 output from the multiple outlet pipes is evenly distributed across the width 1129 of the nonwoven fabric 1130 formed on the collector 1110.

[0090] In one embodiment, as the primary air stream 1126 containing the stream of polymeric fibers 1128 (e.g., microfibers) advances toward the screen of the collector 1110, it draws in a large volume of ambient air (e.g., secondary air stream 1127) that cools and solidifies the fibers in the stream 1128, as shown in FIG. 12E. In some embodiments, the pathogen-killing component 112 is added to the secondary air stream 1127 (e.g., instead of or in addition to the primary air stream 1126). In these embodiments, the pathogen-killing component 112 (e.g., salt crystals) is added to the secondary air stream 1127 from a pathogen-killing component source 1105 (e.g., salt hopper 1205).

[0091] In one embodiment, after being cooled and solidified by the secondary air stream 1127, the solidified stream of fibers 1128 is then randomly laid down on a screen of the collector 1110 to form a self-bonded nonwoven fabric 1130. In one embodiment, the nonwoven fabric 1130 is then used to form a layer 101 of the barrier 100, 100'. FIG. 13 is an image showing an example of a nonwoven fabric 1130 with embedded pathogen-killing components 112 (e.g., salt crystals 1304) formed by the system 1100 of FIG. 11, according to one embodiment. The fibers 1306 are generally laid down randomly (e.g., even highly entangled) due to turbulence in the air stream, with a slight bias in the machine direction due to some directionality imparted by the moving collector 1110. As shown in FIG. 13, in some embodiments, one or more polymer fiber junctions 1308 are formed where multiple polymer fibers 1306 are attached to each other.

[0092] 13, in one embodiment, the nonwoven 1130 is porous and defines a plurality of openings 1302 formed between adjacent polymer fibers 1306. In one embodiment, the embedded pathogen-killing components 112 (e.g., salt crystals 1304) are attached to the polymer fibers 1306 such that a portion of the pathogen-killing components 112 are attached to the polymer fibers 1306 while other portions of the pathogen-killing components 112 extend into the porous openings 1302 between adjacent polymer fibers 1306. In an exemplary embodiment, the size of the pathogen-killing components 112 (e.g., salt crystals 1304) is selected to be large enough to extend into the porous openings 1302 while at the same time being small enough so as not to significantly reduce airflow through the nonwoven 1130 (e.g., not completely block the openings 1302). The inventors of the present invention have recognized that this arrangement advantageously increases the likelihood of contact between the pathogen-killing component 112 (e.g., salt crystals 1304) and a pathogen (e.g., a virus particle) attempting to pass through the openings 1302 of the nonwoven fabric 1130. The inventors of the present invention have recognized that this arrangement is likely to improve the killing efficiency of the nonwoven fabric 1130 when used to form the layer 101 of the barrier 100, 100' to prevent the passage of the pathogen 110 between the first region 102 and the second region 104 (FIGS. 1A and 1B). The inventors of the present invention have also recognized that the method disclosed herein for forming the nonwoven fabric 1130 is time-efficient, since the nonwoven fabric 1130 embedded with the pathogen-killing component 112 can be formed in a relatively short time (e.g., less than an hour).

[0093] In one embodiment, the collector 1110 moves at a speed to collect the nonwoven 1130. In one embodiment, the winder 1112 then collects the nonwoven 1130 onto a reel. In an exemplary embodiment, the speed of the collector 1110 and the distance of the collector 1110 from the spinneret 1220 can be varied to produce different distributions of the pathogen-killing component 112 within the various meltblown webs and / or nonwovens 1130. In some embodiments, a vacuum is applied to the inside of the screen of the collector 1110 to draw out hot air to enhance the fiber lay-down process. In one exemplary embodiment, the collector 1110 is a conveyor.

[0094] In one embodiment, a winder 1112 is provided to collect the nonwoven 1130 into a reel. In one embodiment, the meltblown web is typically wound onto a cardboard core by the winder 1112 and further processed according to end use requirements. In an exemplary embodiment, the combination of fiber entanglement and interfiber bonding generally results in sufficient web bonding so that the web can be easily used without further bonding. However, additional bonding and finishing processes may be further applied to these meltblown webs. Additional bonding to the fiber adhesion and fiber entanglement that occurs during laying is employed to modify the web properties. In an exemplary embodiment, thermal bonding is the most commonly used technique. Bonding can be either global (area bonding) or spot (pattern bonding). Bonding is typically used to improve web strength and abrasion resistance. As the bonding level improves, the web becomes stiffer and less cloth-like.

[0095] In one embodiment, most nonwoven fabrics are considered finished when they are wound up at the end of the production line, but many undergo additional chemical or physical treatments such as calendaring, embossing, and flame retardancy. Some of these treatments can be applied during production, while others must be applied in a separate finishing operation.

[0096] Figure 14 is a flow chart illustrating an example of a method 1400 for using the system of Figure 11 to form the barrier 100, 100' of Figure 1A or Figure 1B, according to one embodiment. Although the steps are depicted in Figure 14 as essential steps in a particular order for purposes of explanation, in alternative embodiments, one or more steps, or portions thereof, may be performed in a different order, or overlap in time, sequentially or in parallel, or may be omitted, or one or more additional steps may be added, or the method may be modified in any combination.

[0097] In one embodiment, in step 1401, polymer pellets are melted in an extruder to form a pressurized molten polymer. In one embodiment, polymer pellets 1120 are added to the extruder 1102 (e.g., through an inlet 1201 shown in FIG. 12A). In one embodiment, the polymer pellets 1120 include one or more of polypropylene, polystyrene, polyester, polyurethane, polyamide, polyethylene, polycarbonate, and polylactic acid (PLA) pellets. In an exemplary embodiment, the polymer pellets 1120 are melted in the extruder 1102 based on a screw 1202 rotating in a heated barrel 1204. The pressurized molten polymer 1122 is then conveyed from the extruder 1102 to a gear pump 1104.

[0098] In one embodiment, a consistent flow of pressurized molten polymer is discharged from the gear pump in step 1403. In one embodiment, in step 1403, a consistent flow of pressurized molten polymer 1124 is discharged from the gear pump 1104 based on the pressurized molten polymer 1122 received by the gear pump 1104 from the extruder 1102.

[0099] In one embodiment, the polymer filament strands are extruded from the die assembly in step 1405. In one embodiment, the polymer filament strands are extruded from the holes of the spinneret 1220 in step 1405 based on a consistent flow of pressurized molten polymer 1124 received from the gear pump 1104.

[0100] In one embodiment, in step 1407, the polymer filament strands extruded in step 1405 are attenuated with air from an air manifold to form a stream of polymer fibers. In one embodiment, in step 1407, the polymer filament strands extruded in step 1405 are attenuated with air from an air manifold 1108 to form a stream of polymer fibers 1128. In this embodiment, the stream of polymer fibers 1128 is directed onto a collector 1110 (e.g., across a width 1129) to form a nonwoven fabric 1130. In some embodiments, in step 1407, a primary air flow 1126 from the air manifold 1108 is used to attenuate the polymer filament strands to form a stream of polymer fibers 1128. In another embodiment, in step 1407, a secondary air flow 1127 from the air manifold 1108 is used to attenuate the polymer filament strands to form a stream of polymer fibers 1128. In yet another embodiment, in step 1407, both the primary air flow 1126 and the secondary air flow 1127 from the air manifold 1108 are used to attenuate the polymer filament strands to form a stream 1128 of polymer fibers.

[0101] In one embodiment, in step 1409, the pathogen-killing component 112 is introduced into the system 1100, 1200 upstream of the collector 1110. In some embodiments, in step 1409, the pathogen-killing component 112 (e.g., salt crystals 1304) is introduced into the primary air stream 1126 and / or secondary air stream 1127 from a pathogen-killing component source 1105 (e.g., salt hopper 1205) during step 1407 so that it adheres to the stream of polymer fibers 1128 that are malleable by step 1407. In another embodiment, in step 1409, the pathogen-killing component 112 is introduced into the gear pump 1104 and / or into the consistent stream of pressurized molten polymer 1124 downstream of the gear pump 1104. In yet another embodiment, in step 1409, the pathogen-killing component 112 is introduced to the extruder 1102 and / or to the pressurized molten polymer 112 downstream of the extruder 1102. In some embodiments, the size of the pathogen-killing component 112 (e.g., salt crystals 1304) is larger than the size of the polymer fibers in various components of the system, and thus, in these embodiments, the pathogen-killing component 112 is not added to components of the system (e.g., extruder 1102), which may feature filters that allow the pathogen-killing component 112 to pass through the polymer fibers but remove the pathogen-killing component 112 from the stream of polymer fibers.

[0102] In one embodiment, after steps 1407 and 1409, a winder is used to collect the formed nonwoven fabric from the collector. In one embodiment, after steps 1407 and 1409, a winder 1112 is used to wind the formed nonwoven fabric 1130 from the collector 1110 onto a reel. In these embodiments, the reel of nonwoven fabric 1130 can then be used to form one or more items or articles comprising the nonwoven fabric 1130.

[0103] In one embodiment, in step 1411, the nonwoven fabric formed by method 1400 is used to form a barrier 100, 100' disposed between the first region 102 and the second region 104 to prevent passage of pathogens 110 between the first region 102 and the second region 104. In one embodiment, in step 1411, the nonwoven fabric 1130 (e.g., formed on a reel by the winder 1112) is used to form one or layer 101 of the barrier 100, 100'. In an exemplary embodiment, in step 1411, the nonwoven fabric 1130 is used to form a face covering (e.g., face coverings 200, 200', 200'', 300, 300'). In yet another embodiment, in step 1411, the nonwoven fabric 1130 is used to form an air filter (e.g., air filter 404, air filter 601, etc.). In yet another embodiment, in step 1411, the nonwoven fabric 1130 is used to form a garment (e.g., garment 500 for a medical professional, any article of clothing or apparel, etc.). In yet another embodiment, in step 1411, the nonwoven fabric 1130 is used to form packaging for a food item (e.g., packaging 1500 of FIG. 15A, packaging 1550 of FIG. 15B, etc.).

[0104] 4. Barrier performance data In one embodiment, the level of crystallization (LOC) of the salt-killed virus component used in the material is measured during X-ray diffraction. X-ray diffraction analysis is a method commonly used in microstructural analysis, specifically to determine the crystal structure of a material. The results of this analysis are quantified by Miller indices, a set of three compound-specific numbers that indicate the orientation of atomic planes in a crystal. Figure 8B is an image showing an example of different Miller indices 850 and their associated orientations of atomic planes in a crystal.

[0105] X-ray diffraction (XRD) is the experimental science of determining the atomic and molecular structure of crystals, which diffract a beam of incident X-rays in many specific directions. By measuring the angles and intensities of these diffracted beams, crystallographers can generate a three-dimensional picture of the density of electrons within the crystal. From this electron density, the average positions of the atoms within the crystal can be determined, as well as their chemical bonds, their crystallographic disorder, and a variety of other information.

[0106] Many materials, such as salts, metals, minerals, semiconductors, and various inorganic, organic, and biomolecules, can form crystals, and therefore XRD has been essential in the development of many scientific fields. In a single crystal X-ray diffraction measurement, a sample (e.g., the barrier 100, 100' or a small portion thereof formed by the methods herein) is mounted on a goniometer. The goniometer is used to position the sample (e.g., the barrier 100, 100') in a selected orientation. The sample (e.g., the barrier 100, 100') is irradiated with a precisely focused monochromatic beam of X-rays, producing a diffraction pattern of regularly spaced spots known as reflections. The two-dimensional images taken at different orientations, combined with known chemical data about the sample, are converted into a three-dimensional model of the density of electrons in the sample (e.g., the barrier 100, 100') using the mathematical method of the Fourier transform.

[0107] FIG. 8A is an image showing an example of a graph 800 depicting the XRD spectrum of the barrier 100, 100' (curve 806) versus the XRD spectrum of the conventional mask 310 (curve 808). The horizontal axis 802 is the orientation of the sample (e.g., the barrier 100, 100') relative to the beam of X-rays employed in the XRD. The vertical axis 804 is the intensity (arbitrary units) indicating the electron density within the sample (e.g., the barrier 100, 100'). As shown by the curve 808 in FIG. 8A, multiple vertices 806a-i occur in the curve 808, indicating the presence of crystalline structure in that orientation of the sample (e.g., the barrier 100, 100'). As also shown in FIG. 8A, the respective Miller indices are shown at each respective vertex 806a-i indicating the Miller indices of the respective vertices. In the exemplary embodiment, vertices 806a through 806i collectively indicate the level of crystallinity (Miller index or vertex in FIG. 8A) of barrier 100, 100' for each plane within barrier 100, 100'.

[0108] In one embodiment, XRD produces a diffraction pattern that provides insight into the atomic structure within the salt crystal, the associated intensity quantifying the electron density within the crystal lattice planes (in arbitrary units, see vertical axis 804). The present inventors have recognized that when lower concentration values ​​of salt are used, the intensity of the XRD diffraction pattern decreases, respectively, since less salt is used. In an exemplary embodiment, vertices 806a through 806i correlate with the vertices of NaCl, since every crystal has unique Miller indices. In an exemplary embodiment, the average intensity achieved at the salt concentration values ​​used herein was about 3 au (arbitrary units), with the crystal-specific vertices having higher values.

[0109] In one embodiment, the filtration efficiency of the barrier 100, 100' is another parameter measured and utilized in developing the barrier 100, 100'. The purpose of particulate filtration efficiency (PFE) is to indicate the adequate filtration of monodisperse particles under a constant flow rate (e.g., using the ASTM F2299 method). In one embodiment, to measure the PFE of the barrier 100, 100', a predetermined amount of polystyrene latex particles (e.g., mean particle size of about 0.216±0.0009 μm; Agar Scientific) is passed through the material at a constant flow rate (e.g., about 10 cm / sec). Light scattering is used to quantify the number of particles downstream. The efficiency value is calculated using the following:

number

[0110] Table 1 below shows the PFE values ​​for the conventional fleece mask, the conventional 3-ply surgical mask, and the barrier 100, 100' (or "amp shield" in Table 1). As shown by the PFE values ​​in Table 1, the filtration efficiency of the barrier 100, 100' is about 98.7%, which is higher than the filtration efficiency of both conventional masks. [Table 1] Figure 9A is an image 900 showing an example of particle light scattering downstream of a conventional mask (e.g., a fleece mask), according to one embodiment. Figure 9B is an image 910 showing an example of particle light scattering downstream of a conventional surgical mask (e.g., a three-ply surgical mask), according to one embodiment. Figure 9C is an image 920 showing an example of particle light scattering downstream of the barrier 100, 100' of the face covering 200 of Figure 2A (e.g., Amp shield of Table 1), according to one embodiment.

[0111] In one embodiment, the viral / bacterial filtration efficiency (VFE / BFE) of the barrier 100, 100' is another parameter measured and utilized in developing the barrier 100, 100'. The purpose of the VFE / BFE is to quantify the performance of the barrier 100, 100' in removing bacteria and viruses (e.g., using the ASTM F2101 method). In one embodiment, the ASTM F2101 method for measuring the BFE is based on an aerosolized liquid suspension of Staphylococcus aureus (e.g., mean particle size 3.5±0.6 μm; Sigma Aldrich) passed through the target material at a constant flow rate of 1 ft3 / min in a six-stage Andersen sampler. Each of the layers includes an agar plate that acts as a medium for the growth of any bacteria that passes through the material.

[0112] In one embodiment, the ASTM F2101 method for measuring VFE is based on aerosolized bacteriophage ΦX174 (e.g., virus-containing droplets with an average size of 3.2±0.4 μm, rather than individual viruses), which infects only E. coli and then targets samples that are inoculated with E. coli, rather than plain agar plates.

[0113] For both BFE and VFE tests, the results are compared to a control test in the absence of barrier 100, 100'. BFE and VFE are calculated using the following:

number

[0114] FIG. 10 is an image showing an example of a graph 1000 depicting the VFE of the barrier 100, 100' of FIG. 1A or FIG. 1B according to one embodiment. The horizontal axis 1002 is exposure time in minutes, and the vertical axis 1004 is the virus layer in pfu / μg. In one embodiment, the bar on the left of each time value shows the virus layer in the conventional mask 310, and the bar on the right of each time value shows the virus layer in the barrier 100, 100'. As shown in FIG. 10, both the conventional mask 310 and the barrier 100, 100' have the same virus layer value (about 1000) at the initial exposure time. As further shown in FIG. 10, after 5 minutes of exposure, the conventional mask 310 still has the same virus layer value (about 1000) at the initial exposure time, while the barrier 100, 100' has a much smaller value (about 10) than the initial exposure. This confirms that after only 5 minutes, the barrier 100, 100' inactivates or kills at least 95% of the virus layer at the initial exposure time. Figure 10 also shows that at later exposure times (e.g., 20 minutes, 60 minutes), the virus layer level on the barrier 100, 100' drops to about 0, while the virus layer level on the conventional mask 310 remains relatively high (about 700). Another embodiment exhibited almost complete hemagglutinin (HA) activity loss. Specifically, glycoproteins essential for viral infectivity were found on the surface of the virus. Through microscopic analysis, we confirmed that the aerosol drying time was approximately 3 minutes. This indicates that the destruction of the virus correlates with salt crystallization due to drying.

[0115] In one embodiment, the fluid resistance of the barrier 100, 100' is another parameter measured and utilized in developing the barrier 100, 100'. The purpose of fluid resistance is to provide adequate resistance to fluid movement from its outer layer to its inner layer due to splashing and spraying. In an exemplary embodiment, a specific method is adopted to measure the fluid resistance (e.g., ASTM F1862). In an exemplary embodiment, 2 mL of synthetic blood is targeted to the barrier 100, 100' at various speeds corresponding to the following blood pressures: 80 mmHg: Level 1, venous blood pressure; 120 mmHg: Level 2, arterial pressure; and 160 mmHg: Level 3, high pressure generated during trauma. In one embodiment, the barrier 100, 100' is an adjunct to current masks, further reducing the number of possible fomites and thus reducing cross contamination while extending the life of current masks. Depending on the setting, the barrier 100, 100' is compliant at all three levels, improving barrier efficiency by adding additional layers. ASTM defines at least 29 of 32 masks as passing fluid without showing it to the other side. Table 4 below shows the number of barriers 100 and 100' that passed and failed at each level. [Table 4]

[0116] In one embodiment, the air exchange (or breathability) of the barrier 100, 100' is another parameter that is measured and utilized in developing the barrier 100, 100'. The air exchange parameter, commonly referred to as ΔP, indicates sufficient breathability for a user wearing the face covering (made from the single layer 101), i.e., the ability of the barrier 100, 100' to restrict the passage of airflow (for example using method EN 14683). In one embodiment, a method for measuring air exchange (or breathability) is employed in step 705 of the method 700, using a pressure gauge to measure the air pressure difference on both sides of the barrier 100, 100' while supplying airflow at a constant flow rate. Table 5 below shows the air exchange (or breathability) values ​​for the FDA approval requirements (top row of Table 5), the conventional mask 310 (second row of Table 5), and the face covering 300 including the conventional mask 310 and the barrier 100, 100' (third row of Table 5). Thus, in one embodiment, air exchange (or breathability) is based on the difference between the third row and the second row of Table 5 (e.g., about 0.05 to about 0.07 mmH20 / cm 2 range). [Table 5] Table 6 below also shows a summary (right-most column of Table 6) of the measured performance parameters of the barrier 100, 100' for the various levels. [Table 6]

Claims

1. 1. A method for forming a barrier configured to be disposed between a first region and a second region to prevent passage of a pathogen between the first region and the second region, the method comprising: meltblowing a stream of polymer fibers onto a surface to form a nonwoven fabric used to create said barrier; Including, The method wherein said meltblowing comprises introducing a pathogen-killing component into said stream of polymer fibers.

2. The method of claim 1 , wherein the polymer fibers comprise one of polypropylene, polystyrene, polyester, polyurethane, polyamide, polyethylene, polycarbonate, and polylactic acid (PLA).

3. The method of claim 1 , wherein the pathogen-killing component comprises one or more of a salt, an acid, and an ester.

4. The method comprises: the location of the introducing step; the particle size of the pathogen-killing component, and an introduction rate at which the pathogen-killing component is introduced into the stream of polymer fibers; 10. The method of claim 1, further comprising determining values ​​for one or more parameters of the introducing step, including at least one of:

5. 5. The method of claim 4, wherein the determining step is based on performing the introducing step when the polymer fibers are malleable such that the pathogen-killing component adheres to the stream of polymer fibers.

6. 5. The method of claim 4, wherein determining the location comprises assessing that the pathogen-killing component having the particle size is not filtered or removed from the stream of polymer fibers downstream of the location.

7. The melt-blowing melting the polymer pellets using an extruder to form a pressurized molten polymer; discharging a consistent flow of pressurized molten polymer received from said extruder using a metering pump; extruding polymer filament strands from the spinneret holes based on the pressurized molten polymer received from the metering pump; attenuating the polymer filament strands with air from an air manifold into a stream of polymer fibers that are directed onto a collector defining a surface for forming the nonwoven fabric; Including, The method of claim 1 , wherein the introducing step is performed downstream of the extruder and upstream of the collector.

8. 8. The method of claim 7, wherein the introducing step is performed such that a pathogen-killing component is introduced into the air manifold used to attenuate polymer filament strands into the stream of polymer fibers.

9. the attenuating step includes directing air from a primary air manifold into a gap between the spinneret and a die nose piece to attenuate the polymer filament strands being extruded from the spinneret bores; 9. The method of claim 8, wherein the pathogen-killing component is introduced into the air from the primary air manifold.

10. the attenuating step includes directing air from a secondary air manifold downstream of the spinneret to attenuate the polymer filament strands being extruded from the spinneret holes; 9. The method of claim 8, wherein the pathogen-killing component is introduced into the air from the secondary air manifold.

11. 9. The method of claim 8, wherein the introducing step is performed using a device configured to evenly distribute the pathogen-killing component across the width of the nonwoven fabric formed on the collector.

12. The device includes an inverted manifold having an inlet pipe having a first diameter and branching into a plurality of outlet pipes having second diameters smaller than the first diameter; 12. The method according to claim 11, wherein the number of the plurality of outlet pipes, the first diameter value, and the second diameter value are selected so that the pathogen-killing component output from the plurality of outlet pipes is evenly distributed across the width of the nonwoven fabric formed on the collector.

13. 12. The method of claim 11, wherein the device includes a hopper configured to gravity feed the pathogen-killing component into the air manifold.

14. 14. The method of claim 13, further comprising a vacuum to return any pathogen-killing component that does not adhere to the stream of polymer fibers to the hopper.

15. 10. The method of claim 1, wherein the nonwoven fabric comprises nonwoven polymeric fibers having porous openings, a first portion of the pathogen-killing component adheres to the nonwoven polymeric fibers, and a second portion of the pathogen-killing component extends into the porous openings between adjacent polymeric fibers of the nonwoven fabric.

16. 16. The method of claim 15, wherein the pathogen-killing component comprises salt such that the first portion of salt crystals adhere to the nonwoven polymeric fibers and the second portion of salt crystals extend into the porous openings between adjacent polymeric fibers of the nonwoven.

17. 10. The method of claim 1, wherein the nonwoven fabric used to create the barrier has a virus kill rate of at least 95%.

18. 1. A system for forming a barrier configured to be disposed between a first region and a second region to prevent passage of pathogens between the first region and the second region, the system including an extruder configured to melt polymer pellets to form a pressurized molten polymer, the system further including a metering pump configured to discharge a consistent flow of the pressurized molten polymer received from the extruder, the system further including a spinneret configured to extrude polymer filament strands from orifices defined by the spinneret based on the pressurized molten polymer received from the metering pump, the system further including an air manifold configured to attenuate the polymer filament strands into a stream of polymer fibers directed onto a collector defining a surface to form the nonwoven fabric; The device is configured to introduce a pathogen-killing component into the stream of polymer fibers downstream of the extruder and upstream of the collector.

19. 10. A barrier formed by the method of claim 1, comprising a first surface facing the first region and a second surface facing the second region.

20. 20. The barrier of claim 19, wherein the pathogen-killing component is a virucidal component comprising a salt having a level of crystallization across the thickness of the barrier from the outer surface of the first side to the outer surface of the second side.

21. 20. The barrier of claim 19, wherein the barrier is a single layer.

22. 20. The barrier of claim 19, wherein the barrier comprises multiple layers, each layer formed by the method of claim 1.

23. 20. The barrier of claim 19, wherein the barrier has a viral filtration efficiency of at least 95% between the first region and the second region.

24. 20. The barrier of claim 19, wherein the barrier is configured to be worn on the face of the user such that the first region is the user's external environment and the second region is the user's face.

25. 25. The barrier of claim 24, further comprising an adhesive on an outer surface of the second side such that the second side is configured to be attached directly to the face of the user with an adhesive.

26. A face covering worn by a user, 10. A barrier formed according to claim 1, wherein the barrier comprises one or more layers; A face covering, wherein the one or more layers are configured to inactivate pathogens incident from the external environment of the user.

27. 27. The face covering of claim 26, further comprising a plurality of layers, each layer formed by the method of claim 1.

28. 20. The barrier of claim 19, wherein the barrier is an air filter configured to be disposed within a conduit of an air conditioning system, the first region being the conduit configured to direct a flow of air, and the second region being an area that receives the flow of air after passing through the air filter.

29. 20. The barrier of claim 19, wherein the barrier is an air filter configured to be placed in a conduit of a ventilator for use with a patient, the first region being the conduit configured to direct a flow of air exhaled by the patient, and the second region being an environment external to the ventilator in a healthcare facility.

30. 20. The barrier of claim 19, wherein the barrier is a garment configured to be worn by a medical professional, the first region being an external environment of the medical professional within a medical facility, and the second region being the body of the medical professional.

31. 20. The barrier of claim 19, wherein the barrier is a food package configured to enclose one or more food items, the first region being an external environment of the one or more food items, and the second region containing the one or more food items.

32. 32. The barrier of claim 31, wherein the food packaging is configured to enclose individual food items such that the barrier is used to individually wrap the one or more food items.

33. 32. The barrier of claim 31 , wherein the food packaging is configured to enclose the container of the one or more food items such that the first region is an environment external to the container and the second region is an interior of the container containing the one or more food items.

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