WO2023031697A1

WO2023031697A1 - Anti-virus respirator and mask

Info

Publication number: WO2023031697A1
Application number: PCT/IB2022/057081
Authority: WO
Inventors: Minghua Dai; Junkang Jacob Liu; Fuming Li; Ta-Hua Yu; Joseph C. Spagnola
Original assignee: 3M Innovative Properties Company
Priority date: 2021-09-01
Filing date: 2022-07-29
Publication date: 2023-03-09

Abstract

An article. The article includes a nonwoven fibrous web; a filtration layer; and a porous substrate in between the nonwoven fibrous web and filtration layer, the porous substrate having two opposing major surfaces and comprising at least a first metal and a second metal; wherein the article is a respirator or a mask.

Description

ANTI-VIRUS RESPIRATOR AND MASK

BACKGROUND

Respirators (sometimes referred to as “filtering face masks” or “filtering face pieces”) are commonly worn over the breathing passages of a person for two common purposes: (1) to prevent impurities or contaminants from entering the wearer's breathing track; and (2) to protect other persons or things from being exposed to pathogens and other contaminants exhaled by the wearer. In the first situation, the respirator is worn in an environment where the air contains particles that are harmful to the wearer, for example, in an auto body shop or in a crowded indoor environment such as an airplane cabin. In the second situation, the respirator is worn in an environment where there is risk of contamination to other persons or things, for example, in an operating room or clean room. During respiratory viral infection, face respirators and masks are thought to prevent transmission. So, there is a need for anti-virus respirators and mask.

SUMMARY

Thus, in one aspect, the present disclosure provides an article, comprising: a nonwoven fibrous web; a filtration layer; and a porous substrate in between the nonwoven fibrous web and filtration layer, the porous substrate having two opposing major surfaces and comprising at least a first metal and a second metal; wherein the article is a respirator or a mask.

Various aspects and advantages of exemplary embodiments of the present disclosure have been summarized. The above Summary is not intended to describe each illustrated embodiment or every implementation of the present disclosure. Further features and advantages are disclosed in the embodiments that follow. The Detailed Description that follows more particularly exemplify certain embodiments using the principles disclosed herein.

DETAILED DESCRIPTION

Before any embodiments of the present disclosure are explained in detail, it is understood that the invention is not limited in its application to the details of use, construction, and the arrangement of components set forth in the following description. The invention is capable of other embodiments and of being practiced or of being carried out in various ways that will become apparent to a person of ordinary skill in the art upon reading the present disclosure. Also, it is understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. It is understood that other embodiments may be utilized, and structural or logical changes may be made without departing from the scope of the present disclosure.

The present disclosure provides an article. The article can include a nonwoven fibrous web, a filtration layer, and a porous substrate in between the nonwoven fibrous web and filtration layer. The porous substrate can have two opposing major surfaces and can have at least two metals. The article can be a respirator or a mask. In some embodiments, the article can include a second nonwoven fibrous web and the filtration layer is in between the porous substrate and the second nonwoven fibrous web. The nonwoven fibrous web or the second nonwoven fibrous web could be used to provide a smooth surface for contacting the wearer's face, or could be used to entrap loose fibers in the mask body, or could be used for aesthetic reasons.

In some embodiments, one opposing major surface of the porous substrate is coated with a first metal layer and a second metal layer that can overlay the first metal layer. In some embodiments, first metal layer can be in direct contact with one opposing major surface of the porous substrate and the second metal layer can be in direct contact with the first metal layer. Alternatively, in some embodiments, the first metal layer is in direct contact with one opposing major surface of the porous substrate and the second metal layer is in direct contact with the other opposing major surface of the porous substrate.

In some embodiments the article includes a first nonwoven fibrous web, a filtration layer, and a porous substrate with one surface of the porous substrate coated with first and second metal layers. The first nonwoven web is adjacent to and in at least partial contact with the metal coated surface of the porous substrate; the filtration layer is adjacent to and in at least partial contact with the surface of the porous substrate opposite from the metal coated surface. In such a construction, the components of the article are oriented in a stacked or layered configuration.

In some embodiments the article includes a first nonwoven fibrous web, a second nonwoven fibrous web, a filtration layer, and a porous substrate with one surface of the porous substrate coated with first and second metal layers. The first nonwoven web is adjacent to and in at least partial contact with the metal coated surface of the porous substrate; the filtration layer is adjacent to and in at least partial contact with surface of the porous substrate opposite from the metal coated surface; and the second nonwoven fibrous web is adjacent to and in at least partial contact with the surface of the filtration layer that is opposite from the porous substrate. In such a construction the components of the article are oriented in a stacked or layered configuration.

Either the first or second metal layer can be a metal oxide such as for example silver oxide or copper oxide.

In some embodiments, the metal substances can be metal coated particles. In some embodiments, particles can be coated with the first metal or the second metal. In some embodiments, particles coated with the first metal and particles coated with the second metal can be on the same opposing major surfaces. Alternatively, particles coated with the first metal and coated with the second metal may be on the different opposing major surfaces. The metal coated particles may be randomly distributed on or in the substrate. In some embodiments, at least some of metal coated particles are discrete particles. In some embodiments, all of metal coated particles are discrete particles. In some embodiments, the surface of the substrate is partially covered with particles so that the substrate surface is partially exposed. In some embodiments, 2% to 95%, 2% to 80%, 2% to 50%, or 2% to 30% of the substrate surface area is not covered by particles. In some embodiments, at least 5%, 10%, 20%, 40%, 50%, 70%, or 85% of the substrate surface area is covered with particles. In some embodiments, no more than 98%, 95%, 90%, 85%, 70%, 50%, 40% or 30% of the substrate surface area is covered with particles.

Porous Substrate

The porous substrate can be any suitable substrate, for example, foam, mesh, netting, woven, nonwoven, cotton, cellulose fabrics, perforated film, hydrocolloid, hydrogel, polymers with inherent porosity, pressure sensitive adhesive and combination of thereof. In some embodiments, the substrate can be an absorbent substrate. Exemplary absorbent substrate can include film, fabrics or porous article made from viscose, rayon, alginate, gauze, biopolymers, polyurethane, biodegradable polymers or the polymers described in US Patent No. 7,745,509, the disclosures of which is hereby incorporated by reference. The absorbent materials used in the absorbent substrate can be manufactured of any suitable materials including, but not limited to, woven or nonwoven cotton or rayon or netting and perforated film made from nylon, polyester or polyolefins.

The absorbent layer may include a hydrocolloid composition, including the hydrocolloid compositions described in U.S. Patent Nos. 5,622,711 and 5,633,010, the disclosures of which are hereby incorporated by reference. The hydrocolloid absorbent may comprise, for example, a natural hydrocolloid, such as pectin, gelatin, or carboxymethylcellulose (CMC) (Aquaion Corp., Wilmington, Del.), a semisynthetic hydrocolloid, such as cross-linked carboxymethylcellulose (X4ink CMC) (e.g. Ac-Di-Sol; FMC Corp., Philadelphia, Pa.), a synthetic hydrocolloid, such as cross-linked polyacrylic acid (PAA) (e.g., CARBOPOL™ No. 974P; B.F. Goodrich, Brecksville, Ohio), or a combination thereof. Absorbent layer can be manufactured of other synthetic and natural hydrophilic materials including polymer gels and foams.

In some embodiments, the porous substrate can have air-permeability. For example, the porous substrate can have a pressure resistance is in the range of 2.6 to 3.3 (mm H₂O) measured at a face velocity of around 14 cm/s.

In some embodiments, the porous substrate can have a salt, for example, NaCl, CaCL. KC1, Na₂ SO4, NaHCOi. NaH₂PO4, and KA1(SC>4)₂. The addition of salt to porous substrate may facilitate preventing or reducing the transmission of infections such as flu, viral and bacterial pathogens, for example, by killing attached vims.

Metal Laver

A used herein, “metal” includes metal and metal compounds, such as, metal oxide. For example, in some embodiments, the first metal is a metal, and the second metal is a metal oxide, in some embodiments, the first metal layer comprises a metal oxide and the second metal layer comprises a metal. The metal can include those known to have a positive electric potential. The metal oxide can be those known to have an anti-microbial effect. The first metal can include, but not limited to, silver, copper, gold, platinum, zinc, magnesium, titanium, chromium and combinations thereof. The second metal can include, but not limited to, zinc, magnesium, aluminum, iron, calcium, tin, copper, titanium, chromium, nickel and alloys thereof. In some embodiments, the electric potential differences of the first metal and second metal are more than 0.05 V, 0.1 V, 0.2 V, 0.3 V, 0.5 V, 1 V, 2 V, 3 V or 5 V. In some embodiments, the first metal layer comprises silver oxide or copper oxide. In some embodiments, the second metal layer comprises copper or zinc. In some embodiments, the first metal layer comprises silver oxide and the second metal layer comprises copper. In some embodiments, the first metal layer comprises copper and the second metal layer comprises silver oxide. In some embodiments, the first metal layer comprises silver oxide and the second metal layer comprises zinc. In some embodiments, the first metal layer comprises zinc and the second metal layer comprises silver oxide.

The metal layer can be formed by any suitable means, for example, by vapor deposition techniques. The vapor deposition techniques can include, but is not limited to, vacuum or arc evaporation, sputtering, magnetron sputtering and ion plating. Suitable physical vapor deposition techniques can include those described in US Patent Nos. 4,364,995; 5,681,575 and 5,753,251, the disclosures of which are hereby incorporated by reference. In some embodiments, the first metal layer is coated on the opposing surface of the porous substrate by vapor deposition. . In some embodiments, the second metal layer is coated over the first metal layer by vapor deposition.

The metal layer can be formed as a thin film. The film can have a thickness no greater than that needed to provide release of metal ions on a sustainable basis over a suitable period of time. In that respect, the thickness will vary with the particular metal in the coating (which varies the solubility and abrasion resistance), and with the amount of the oxygen containing gas or vapor introduced to the metal vapor stream. The thickness will be thin enough that the metal layer does not interfere with the dimensional tolerances or flexibility of the article for its intended utility. Typically, the metal layer has a thickness of less than 1 micron. However, it is understood that increased thicknesses may be used depending on the degree of metal ion release needed over a period of time.

In some embodiments, the first and second metal layers have a combined thickness of 2 microns or less. In some embodiments, the first and second metal layers have a combined thickness of 1 micron or less. In some embodiments, the first and second metal layers have a combined thickness of 700 nm or less. In some embodiments, the first and second metal layers have a combined thickness of 500 nm or less. In some embodiments, the first and second metal layers have a combined thickness of 100-1000 nm, 100-700 nm, 100-500 nm, 100-300 nm, or 150-300 nm.

In some embodiments, the first metal layer is about 50-200 nm thick, and the second metal layer is about 50-200 nm thick. In some embodiments, the first metal layer is about 50-150 nm thick, and the second metal layer is about 50-150 nm thick. Particles

The particles of the present disclosure can be any suitable particles, for example, non-metal particles. In some embodiments, the particle material can be an electrical insulator, for example, cellulose particles. The cellulose in the particles, can be powdered cellulose or can be modified celluloses, such as methylcellulose, cellulose acetate, and, and hydroxypropylmethylcellulose . The particles can be any suitable plastic particles. For example, polystyrene particles, polyethylene particles, polypropylene particles, PET particles, poly(methylmethacrylate) particles, and polyurethane particles can be used. Plastic particles can be made of natural and/or synthetic polymers. Plastic particles can be made of a single polymer or a blend of polymers.

The size of particles can be from about 1 micrometer to about 1000 micrometers, from about 1 micrometer to about 500 micrometers or from about 1 micrometer to about 100 micrometers.

The particles can be coated by metal or metal oxide through any suitable means, for example, by physical vapor deposition techniques. The physical vapor deposition techniques can include, but is not limited to, vacuum or arc evaporation, sputtering, magnetron sputtering and ion plating. Suitable physical vapor deposition techniques can include those described in US Patent Nos. 4,364,995; 5,681,575 and 5,753,251, the disclosures of which are hereby incorporated by reference.

For metal oxide coating, by the controlled introduction of reactive material, for example, oxygen into the metal vapor stream of vapor deposition apparatus during the vapor deposition of metals onto particles, controlled conversion of the metal to metal oxides can be achieved. Therefore, by controlling the amount of the reactive vapor or gas introduced, the proportion of metal to metal oxide in the metal oxide layer can be controlled. For 100% conversion of the metal to metal oxides at a given level of the layer, at least a stoichiometric amount of the oxygen containing gas or vapor is introduced to a portion of the metal vapor stream. When the amount of the oxygen containing gas increases, the metal oxide layer will contain a higher weight percent of metal oxide. The ability to achieve release of metal atoms, ions, molecules or clusters on a sustainable basis can be affected by varying the amount of the oxygen containing gas. As the amount of metal oxide increases when the level of oxygen containing gas introduced increases, metal ions released from the article in turn increases. Thus, a higher weight percent of metal oxide can, for example, provide an enhanced release of anti-microbial agents, such as metal ions and provide an increased antimicrobial activity.

The metal oxide and/or metal coated particles can be fully coated or partially coated. In the embodiment shown in Fig. 1, particles 20 are fully coated with the metal oxide 22 and particles 30 are fully coated with the metal 32. In some embodiments shown in Fig. 2, the surface of the particles 20 or particles 30 is partially covered with the metal oxide 22 or the metal 32 so that the particle surface is partially exposed. Partially coated particles contain both coated and uncoated areas on the particle surface. In some embodiments, at least some of the metal oxide coated particles are partially coated. In some embodiments, at least some of the metal coated particles are partially coated. For partially coated particles, at least some of the particle surface is exposed. In some embodiments, at least 5%, 10%, 20%, 30%, 50%, or 70% of the particle surface is exposed (i.e. uncoated). In some embodiments, no more than 95%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, or 10% of the particle surface is exposed (i.e. uncoated).

In some embodiments, the article contains partially coated particles having at least 10% of the particle surface exposed (i.e. uncoated). In some embodiments, the article contains partially coated particles having at least 20% of the particle surface exposed (i.e. uncoated). In some embodiments, the article contains partially coated particles having at least 30% of the particle surface exposed (i.e. uncoated). In some embodiments, the article contains partially coated particles having at least 50% of the particle surface exposed (i.e. uncoated).

In some embodiments, the exposed particle surface is cellulose or modified cellulose. In some embodiments, the exposed particle surface is a polymer that is an electrical insulator.

In some embodiments, the article contains partially coated particles having at least 10% of the particle surface coated. In some embodiments, the article contains partially coated particles having at least 20% of the particle surface coated. In some embodiments, the article contains partially coated particles having at least 30% of the particle surface coated. In some embodiments, the article contains partially coated particles having at least 50% of the particle surface coated. In some embodiments, the article contains partially coated particles having at least 75% of the particle surface coated. In some embodiments, the article contains partially coated particles having at least 85% of the particle surface coated.

In some embodiments, the article contains partially coated particles having no more than 95%, 90%, 85%, or 75% of the particle surface coated. In some embodiments, the article contains partially coated particles having no more than 90% of the particle surface coated.

In some embodiments, the partially coated particles are metal oxide coated particles. In some embodiments, the partially coated particles are silver oxide coated particles. In some embodiments, the partially coated particles are metal coated particles. In some embodiments, the partially coated particles are copper coated particles.

Nonwoven Fibrous Web

The nonwoven fibrous web can be of a particle capture or gas and vapor type. Examples of particle capture nonwoven fibrous webs include one or more webs of fine inorganic fibers (such as fiberglass) or polymeric synthetic fibers. Synthetic fiber webs may include electret charged polymeric microfibers that are produced from processes such as meltblowing. Polyolefin microfibers formed from polypropylene that are electret charged, to produce non-polarized trapped charges, provide particular utility for particulate capture applications.

The nonwoven fibrous web is typically chosen to achieve a desired filtering effect and, generally, removes a high percentage of particles or other contaminants from the gaseous stream that passes through it. For nonwoven fibrous web, the fibers selected depend upon the kind of substance to be filtered and, typically, are chosen so that they do not become bonded together during the molding operation. As indicated, the nonwoven fibrous web may come in a variety of shapes and forms. It typically has a thickness of about 0.2 millimeters to 1 centimeter, more typically about 0.3 millimeters to 0.5 centimeter, and it could be a planar web coextensive with a shaping or stiffening layer, or it could be a corrugated web that has an expanded surface area relative to the shaping layer — see, for example, U.S. Pat. Nos. 5,804,295 and 5,656,368 to Braun et al. The nonwoven fibrous web also may include multiple layers of filter media joined together by an adhesive component. Essentially any suitable material that is known for forming a filtering layer of a direct-molded respiratory mask may be used for the mask filtering material. Webs of melt-blown fibers, such as those described in Wente, Van A., Superfine Thermoplastic Fibers, 48 Indus. Engn. Chem., 1342 et seq. (1956), especially when in a persistent electrically charged (electret) form, are especially useful (see, for example, U.S. Pat. No. 4,215,682 to Kubik et al.). These melt-blown fibers may be microfibers that have an effective fiber diameter less than about 20 micrometers (pm) (referred to as BMF for “blown microfiber”), typically about 1 to 12 pm. Effective fiber diameter may be determined according to Davies, C. N., The Separation Of Airborne Dust Particles, Institution Of Mechanical Engineers, London, Proceedings IB, 1952. Particularly preferred are BMF webs that contain fibers formed from polypropylene, poly(4-methyl-l -pentene), or combinations thereof. Electrically charged fibrillated- film fibers as taught in van Turnhout, U.S. Pat. No. Re. 31,285, may also be suitable, as well as rosin-wool fibrous webs and webs of glass fibers or solution-blown, or electrostatically sprayed fibers, especially in microfilm form. Electric charge can be imparted to the fibers by contacting the fibers with water as disclosed in U.S. Pat. No. 6,824,718 to Eitzman et al., U.S. Pat. No. 6,783,574 to Angadjivand et al., U.S. Pat. No. 6,743,464 to Insley et al., U.S. Pat. Nos. 6,454,986 and 6,406,657 to Eitzman et al., and U.S. Pat. Nos. 6,375,886 and 5,496,507 to Angadjivand et al. Electric charge also may be impacted to the fibers by corona charging as disclosed in U.S. Pat. No. 4,588,537 to Klasse et al. or tribocharging as disclosed in U.S. Pat. No. 4,798,850 to Brown. Also, additives can be included in the fibers to enhance the filtration performance of webs produced through the hydro-charging process (see U.S. Pat. No. 5,908,598 to Rousseau et al.). Fluorine atoms, in particular, can be disposed at the surface of the fibers in the filtration layer to improve filtration performance in an oily mist environment — see U.S. Pat. Nos. 6,398,847 Bl, 6,397,458 Bl, and 6,409,806 Bl to Jones et al. Typical basis weights for electret BMF nonwoven fibrous web are about 15 to 100 grams per square meter. When electrically charged according to techniques described in, for example, the '507 patent, the basis weight may be about 20 to 40 g/m² and about 10 to 30 g/m², respectively.

In some embodiments, the nonwoven fibrous web and/or the second nonwoven fibrous web could can have a salt, for example, NaCl, CaCT. KC1, Na2 SO4, NaHCO,. NaEfiPCfi, and K AUSOJL. The addition of salt to nonwoven fibrous web and/or the second nonwoven fibrous web may facilitate preventing or reducing the transmission of infections such as flu, viral and bacterial pathogens, for example, by killing attached vims. Filtration Laver

Filtration layers used in the article of the present disclosure can include those described in U.S. Patent No. 9,770,611 (Facer et al.) and U.S. Patent No. 10,827,787 (Facer et al.). For example, filtration layers can be of a particle capture or gas and vapor type. The filtration layer also may be a barrier layer that prevents the transfer of liquid from one side of the filtration layer to another to prevent, for instance, liquid aerosols or liquid splashes from penetrating the filtration layer. Multiple layers of similar or dissimilar filtration types may be used to construct the filtration layer of the invention as the application requires. Filtrations that may be beneficially employed in a layered mask body of the invention are generally low in pressure drop (for example, less than about 20 to 30 mm H₂O at a face velocity of 13.8 centimeters per second) to minimize the breathing work of the mask wearer. Filtration layers additionally are flexible and have sufficient shear strength so that they generally retain their structure under the expected use conditions. Generally, the shear strength is less than that either the adhesive or shaping layers. Examples of particle capture filtrations include one or more webs of fine inorganic fibers (such as fiberglass) or polymeric synthetic fibers. Synthetic fiber webs may include electret charged polymeric microfibers that are produced from processes such as meltblowing. Polyolefin microfibers formed from polypropylene that has been electret charged to provide particular utility for particulate capture applications. An alternate filtration layer may comprise an sorbent component for removing hazardous or odorous gases from the breathing air. Sorbents may include powders or granules that are bound in a filtration layer by adhesives, binders, or fibrous structures — see U.S. Pat. No. 3,971,373 to Braun. A sorbent layer can be formed by coating a substrate, such as fibrous or reticulated foam, to form a thin coherent layer. Sorbent materials may include activated carbons that are chemically treated or not, porous alumna-silica catalyst substrates, and alumna particles.

The filtration layer is typically chosen to achieve a desired filtering effect and, generally, removes a high percentage of particles and/or or other contaminants from the gaseous stream that passes through it. For fibrous filtration layers, the fibers selected depend upon the kind of substance to be filtered and, typically, are chosen so that they do not become bonded together during the molding operation. As indicated, the filtration layer may come in a variety of shapes and forms. It typically has a thickness of about 0.2 millimeters (mm) to 1 centimeter (cm), more typically about 0.3 millimeters to 0.5 cm, and it could be a planar web coextensive with a shaping or stiffening layer, or it could be a corrugated web that has an expanded surface area relative to the shaping layer — see, for example, U.S. Pat. Nos. 5,804,295 and 5,656,368 to Braun et al. The filtration layer also may include multiple layers of filter media joined together by an adhesive component. Essentially any suitable material that is known for forming a filtering layer of a direct-molded respiratory mask may be used for the filtering material. Webs of melt-blown fibers, such as taught in Wente, Van A., Superfine Thermoplastic Fibers, 48 Indus. Engn. Chem., 1342 et seq. (1956), especially when in a persistent electrically charged (electret) form are especially useful (see, for example, U.S. Pat. No. 4,215,682 to Kubik et al.). These melt-blown fibers may be microfibers that have an effective fiber diameter less than about 20 micrometers (pm) (referred to as BMF for “blown microfiber”), typically about 1 to 12 pm. Effective fiber diameter may be determined according to Davies, C. N., The Separation Of Airborne Dust Particles, Institution Of Mechanical Engineers, London, Proceedings IB, 1952. Particularly preferred are BMF webs that contain fibers formed from polypropylene, poly(4-methyl-l -pentene), and combinations thereof. Electrically charged fibrillated-film fibers as taught in van Turnhout, U.S. Pat. Re. 31,285, may also be suitable, as well as rosin-wool fibrous webs and webs of glass fibers or solution-blown, or electrostatically sprayed fibers, especially in microfilm form. Electric charge can be imparted to the fibers by contacting the fibers with water as disclosed in U. S. Pat. No. 6,824,718 to Eitzman et al., U.S. Pat. No. 6,783,574 to Angadjivand et al., U.S. Pat. No. 6,743,464 to Insley et al., U.S. Pat. No. 6,454,986 and U.S. Pat. No. 6,406,657 to Eitzman et al., and U.S. Pat. No. 6,375,886 and U.S. Pat. No. 5,496,507 to Angadjivand et al. Electric charge may also be impacted to the fibers by corona charging as disclosed in U.S. Pat. No. 4,588,537 to Klasse et al. or tribocharging as disclosed in U. S. Pat. No. 4,798,850 to Brown. Also, additives can be included in the fibers to enhance the filtration performance of webs produced through the hydro-charging process (see U.S. Pat. No. 5,908,598 to Rousseau et al.). Fluorine atoms, in particular, can be disposed at the surface of the fibers in the filtration layer to improve filtration performance in an oily mist environment — see U.S. Pat. Nos. 6,398,847 Bl, 6,397,458 Bl, and 6,409,806 Bl to Jones et al. Typical basis weights for electret BMF filtration layers are about 15 to 100 grams per square meter. When electrically charged according to techniques described in, for example, the '507 patent, and when including fluorine atoms as mentioned in the Jones et al. patents, the basis weight may be about 20 to 40 g/m² and about 10 to 30 g/m², respectively.

Optional Components

Suitable binder layer can be overlaying the first metal and the second metal. Suitable binder includes any adhesive that provides acceptable adhesion to skin and is acceptable for use on skin (e.g., the adhesive should preferably be non-irritating and non-sensitizing). Suitable adhesives are pressure sensitive and in certain embodiments have a relatively high moisture vapor transmission rate to allow for moisture evaporation. Suitable pressure sensitive adhesives include those based on acrylates, urethane, hyrdogels, hydrocolloids, block copolymers, silicones, rubber-based adhesives (including natural rubber, polyisoprene, polyisobutylene, butyl rubber etc.) as well as combinations of these adhesives. The adhesive component may contain tackifiers, plasticizers, rheology modifiers as well as active components including for example an antimicrobial agent. Suitable adhesive can include those described in U.S. Patent Nos. 3,389,827; 4,112,213; 4,310,509; 4,323,557; 4,595,001; 4,737,410; 6,994,904 and International Publication Nos. WO 2010/056541; WO 2010/056543 and WO 2014/149718, the disclosures of which are hereby incorporated by reference.

Suitable release liners can be made of Kraft papers, polyethylene, polypropylene, polyester or composites of any of these materials. In one embodiment, the package that contains the adhesive dressing may serve as a release liner. In one embodiment, the liners are coated with release agents such as fluorochemicals or silicones. For example, U.S. Pat. No. 4,472,480, the disclosure of which is hereby incorporated by reference, describes low surface energy perfluorochemical liners. In one embodiment, the liners are papers, polyolefin films, or polyester films coated with silicone release materials.

The nonwoven fibrous web or webs, filtration layer, and porous substrate components of an article can be edge sealed using any suitable edge sealing means such as for example an adhesive, stitching, staples, or melt bonding to form the seal.

Properties

The anti-microbial effect of the article can be achieved, for example, when the article is brought into contact with an alcohol or a water-based electrolyte such as, a body fluid or body tissue, thus releasing metal ions such as Ag⁺, atoms, molecules or clusters. The concentration of the metal which is needed to produce an anti-microbial effect will vary from metal to metal. Generally, anti-microbial effect is achieved in body fluids such as respiratory aerosols, respiratory droplets, saliva, nasal secretions, tears, occular fluid, sweat, mucus, plasma, serum or urine at concentrations less than 10 ppm. In some embodiments, Ag⁺ release concentration from the article can be 0.1 ppm, 0.5 ppm, 1 ppm, 2 ppm, 2.5 ppm, 3 ppm, 4 ppm, 5 ppm, 6 ppm, 7 ppm, 8 ppm, 9 ppm, 10 ppm or a range between and including any two of these values. In addition, the article can generate at least one electrical current when introduced to an electrolytic solution. In some embodiments, the article is capable of generating a current in a range from about 10 pA to about 5000 pA when introduced to an electrolytic solution. In some embodiments, the article is capable of generating a current in a range from about 100 pA to about 1000 pA when introduced to an electrolytic solution. In the presence of an electrically conducting solution, redox reactions may take place, and thus currents may be produced between the first and second metal. For example, when the first metal is a metal oxide layer including silver oxide and the second metal is a metal layer including zinc, silver oxide is the cathode (positive electrode) and zinc is the anode (negative electrode), because the electrons follow from zinc to silver oxide. The flow of ions generates the electrical current. The current can inhibit the growth of microbial, such as, bacteria and virus. Therefore, the current generated by the article can have synergistic antimicrobial functionality along with Ag⁺ release from the article. In addition, salt, for example, NaCl of the nonwoven fibrous web can increase the antimicrobial functionality. Therefore, the article of the present disclosure can provide a very effective anti-microbial effect. In some embodiments, the article can exhibit a more than 4, more than 5, more than 6, or more than 6.5 logarithmic reduction value (LRV) of virus growth within 7 days, 6 days, 5 days, 4 days, 3, days, 2 days, 1 day, 12 hours, 6 hours, 3 hours, 1 hour, 30 minutes, 20 minutes, 15 minutes, or 10 minutes. In some embodiments, the article can at least partially kill virus within 7 days, 6 days, 5 days, 4 days, 3, days, 2 days, 1 day, 12 hours, 6 hours, 3 hours, 1 hour, 30 minutes, 20 minutes, 15 minutes, or 10 minutes. In some embodiments, the article can completely kill virus within 7 days, 6 days, 5 days, 4 days, 3, days, 2 days, 1 day, 12 hours, 6 hours, 3 hours, 1 hour, 30 minutes, 20 minutes, 15 minutes, or 10 minutes. In some embodiments, no colonies of vims can be observed after application of the article. EXAMPLES

Objects and advantages of this invention are further illustrated by the following examples, but the particular materials and amounts thereof recited in these examples, as well as other conditions and details, should not be construed to unduly limit this invention.

The materials used to prepare examples of the invention (Ex) as well as comparative examples (CE) are outlined below.

Materials

Sodium chloride, tris(hydroxymethyl)aminomethane hydrochloride (Tris-HCl), magnesium sulfate, magnesium chloride, polyethylene glycol 8000 (PEG 8000, average MW of 8000), lysogeny agar, tryptone, yeast extract, and agar were obtained from the Sigma-Aldrich Company (St. Louis, MO).

Tryptic Soy Agar was obtained from the Becton, Dickinson Company (Franklin Lakes, NJ). The agar preparation was autoclaved (instrument setting of 121 °C for 15 minutes) prior to use.

Enveloped Phi6 phage (DSM 21518) and its host strain Pseudomonas syringae strain (DSM 21482) were obtained from the DSMZ-German Collection of Microorganisms and Cell Cultures GmbH (Braunschweig Germany).

Lysogeny media was prepared by mixing sodium chloride (10 g), tryptone (10 g), and yeast extract (5 g) in deionized water (1 L) at pH 7. The media was sterilized using an autoclave and then allowed to cool to room temperature.

Soft lysogeny agar plates were prepared by adding tryptone (10 g), yeast extract (5 g), sodium chloride (5 g), magnesium chloride (1 g), and agar (7.5 g) to deionized water (1 L). The resulting product was autoclaved (instmment setting of 121 °C for 15 minutes), separated into 50 mL aliquots, and stored as a solid at room temperature. Prior to use, the soft agar was melted using a micro wave oven.

PEG/NaCl (5X) stock solution was prepared by dissolving 100 g PEG-8000 (100 g) and NaCl (75 g) in deionized water (400 mL) and then sterilizing the solution using an autoclave. Post sterilization, deionized water was added with stirring at room temperature to bring the final volume to 500 mL. The solution was mixed thoroughly by inversion and chilled in an ice bath (or in a refrigerator) for 2 hours.

SM Buffer Preparation: Stock solutions of NaCl (IM) , Tris-HCl (IM), and magnesium sulfate (IM) were prepared using deionized water. The reagents were combined to provide a solution of NaCl (200 mM), Tris-HCl (10 mM), and magnesium sulfate (1 mM). Gelatin (100 micrograms/mL) was then added to the solution.

Phi6 Phage Production

Enveloped Phi6 phage and its host strain Pseudomonas syringae strain were propagated in lysogeny media. Bacterial cultures were initiated by transferring a single colony from a streak plate into 10 mL of lysogeny media in a sterile 50 mL Erlenmeyer flask. The Pseudomonas syringae culture flasks were incubated with shaking (250 rpm) at 25 °C for 18 hours allowing bacteria to attain stationary phase (cell density of 1 x 10⁸ cells per mL). Phages from a single plaque that was grown in a separate soft lysogeny agar plate were transferred to the bacteria culture by using a disposable plastic loop. Bacterial cultures were continued to be grown until all the host bacteria cells were lysed (about 12 hours). The phages were then harvested from the liquid culture by centrifugation at 5000 rpm for 10 minutes to remove bacterial cell debris. The resulting supernatant containing the phage was precipitated by adding the 5X PEG/NaCl solution. The phage was then pelleted by microcentrifugation for 30 minutes at 13,000 g. Post centrifugation, the supernatant was removed and the pellet containing the phage was resuspended in SM buffer or stored at 4 °C until used.

Determination of Phi6 Phage Concentration in Assay Samples

TSB agar was poured into plates and the plates were cooled until the agar solidified. Next, soft TSB agar (4 mL, maintained at 50 °C) containing 0.5 mL of Pseudomonas syringae culture (OD600 = 0.4- 0.7) was poured on top of the solidified TSB agar plate. Each resulting agar plate was cooled to room temperature. Each phage sample was serially diluted (10-fold dilutions) in a 96 well plate starting with a set of wells each containing 90 microliters of SM buffer solution mixed with 10 microliters of the phage containing solution. From each serial dilution, 3 microliters of phage containing solution was spotted onto the top of the soft agar using a pipette. The inoculated plates were incubated overnight at 25 °C. Following incubation, the number of plaque forming units (pfu) were counted. The Phi6 phage concentration (pfu/mL) was calculated.

Example 1.

The porous substrate was a polypropylene BMF (Blown Micro Fiber) nonwoven web having a basis weight at 62 gsm, effective fiber diameter (EFD) of about 16 micrometers, solidity of about 18-20%, and thickness of about 12 mil (0.3 mm).

Coatings were deposited on the nonwoven web substrate using a PVD75 vacuum deposition system (from Kurt J. Lesker Company, Jefferson Hills, PA). The substrate was placed on a substrate holder in the system chamber. A silver oxide coating was deposited by DC reactive sputtering of a >99% silver cathode target (from Kurt Lesker Co.) onto the exposed surface of the substrate. The system was operated at 200 watts, a pressure of 5 millitorr, and a 4.8 standard cubic centimeters per minute (seem) oxygen gas flow rate with the balance argon gas. Sputtering for about 3 minutes produced a 100 nm thick AgO coating. A copper coating was then deposited over the AgO coating by RF sputtering of a >99% copper cathode target (from Kurt Lesker Co.). The system was operated at 200 watts, a pressure of 2 millitorr with 50 seem argon gas. Sputtering for about 10 minutes produced a 100 nm thick copper coating.

The coating procedure was conducted in two separate trials (each trial using the same conditions) to prepare Coated Substrate A and Coated Substrate B. Example 2. Pressure Resistance of Coated and Uncoated Nonwoven Web Substrates

Pressure resistance (AP) across substrate samples (in mm of water) was determined using an Automated Filter Tester AFT Model 8130 (available from TSI, Inc., St. Paul, MN) with dioctyl phthalate (DOP) as the challenge aerosol and an MKS pressure transducer that measured pressure drop (AP [mm H₂O]) across the filter. The DOP was nominally a monodisperse 0.3 micron mass median diameter aerosol with an upstream concentration of approximately 100 mg/m³. The aerosol was forced through the substrate at a calibrated flow rate face velocity of 13.8 centimeters per second. The total testing time was 23 seconds (rise time of 15 seconds, sample time of 4 seconds, and purge time of 4 seconds). Six separate measurements were made at the same location of the substrate and the mean value was reported. In addition to the coated substrates of Example 1 (Coated Substrate A and Coated Substrate B), an uncoated nonwoven substrate sample was tested as a Control Example. The results are presented in Table 1. Coating of the substrate with AgO and copper layers did not substantially alter the pressure resistance of the substrate.

Table 1.

Example 3.

Circular discs (1 cm diameter) were punched from the coated substrates prepared in Example 1. For each sample, three replicates were prepared and tested (n=3). A single disc was placed in a sterile 100 x 15 mm plastic Petri dish and oriented so that the uncoated surface of the disc contacted the base of the dish. An aliquot (100 microliters) of Phi6 phage in SM buffer (l x 10¹⁰ pfu/mL) was deposited on the coated surface of each disc using a micropipette. Each disc then covered with a sterile, glass microscope slide coverslip. Control samples (n=3) were also prepared by depositing a 100 microliter aliquot of the Phi6 phage sample directly on the base surface of a Petri dish that did not contain an added disc. The added aliquot was subsequently covered with a sterile, glass microscope slide coverslip. Each Petri dish was placed in an incubator at room temperature for 10 minutes. After removal from the incubator, the cover slip and disc were separated from each other while still keeping them in the Petri dish. An aliquot (10 mL) of phosphate buffered saline (PBS) (IX, Thermo Fisher Scientific, Waltham, MA) was added to each Petri dish and the Petri dish was gently shaken for 10 minutes at 100 rpm (revolutions per minute) using a MAXQ Model 8000 orbital shaker (Thermo Fisher Scientific). The resulting PBS solution was serially diluted and analyzed for Phi6 phage according to the procedure ‘Determination of Phi6 Phage Concentration in Assay Samples’ described above.

The pfu counts of the individual plates (n=3) were averaged and the average count value was used to calculate (based on serial dilutions) the number of plaque forming units per milliliter (pfu/mL) that were recovered from each inoculated disc. For each example disc, the logarithmic reduction value (LRV) was calculated according to Equation 1. The results are reported in Table 2. The LRV of >6.8 reported in Table 2 indicates that no colonies were observed in any of the dilution samples for the example disc.

Equation 1 :

Table2.

All references and publications cited herein are expressly incorporated herein by reference in their entirety into this disclosure. Illustrative embodiments of this invention are discussed, and reference has been made to possible variations within the scope of this invention. For example, features depicted in connection with one illustrative embodiment may be used in connection with other embodiments of the invention. These and other variations and modifications in the invention will be apparent to those skilled in the art without departing from the scope of the invention, and it should be understood that this invention is not limited to the illustrative embodiments set forth herein. Accordingly, the invention is to be limited only by the claims provided below and equivalents thereof.

Claims

What is claimed is:

1. An article, comprising: a nonwoven fibrous web; a filtration layer; and a porous substrate in between the nonwoven fibrous web and filtration layer, the porous substrate having two opposing major surfaces and comprising at least a first metal and a second metal; wherein the article is a respirator or a mask.

2. The article of claim 1, wherein the electrode potential differences of the two metals are more than 0.05 V.

3. The article of any of claims 1-2, wherein one opposing major surface is coated with a first metal layer and the second metal layer overlays the first metal layer.

4. The article of any of claims 1-3, wherein the first metal layer is in direct contact with one opposing major surface of the substrate and the second metal layer is in direct contact with the other opposing major surface of the substrate.

5. The article of any of claims 1-4, wherein the first metal and the second metal comprise metal coated particles.

6. The article of claim 5, wherein the coated particles are randomly distributed on or in the substrate.

7. The article of claim 5, wherein at least some of coated particles are discrete particles.

8. The article of any of claims 1-7, further comprising an optional binder layer overlaying the first metal and the second metal.

9. The article of any of claims 1-8, wherein the porous substrate comprises a nonwoven, woven, or perforated film.

10. The article of any of claims 1-9, wherein the first metal is selected from silver, copper, gold, platinum, zinc, magnesium, titanium, chromium and combinations thereof.

11. The article of any of claims 1-10, wherein the second metal is selected from zinc, magnesium, aluminum, iron, calcium, tin, copper, titanium, chromium, nickel and alloys thereof.

12. The article of any of claims 1-11, wherein the article is capable of generating at least one electrical current when introduced to an electrolytic solution.

13. The article of any of claims 1-12, wherein the article is capable of generating a current in a range from about 1 pA to about 5000 pA when introduced to an electrolytic solution.

14. The article of any of claims 1-13, wherein the article has anti-virus efficacy of more than 4 logarithmic reduction value (LRV) of virus growth within 7 days.

15. The article of any of claims 1-14, wherein the nonwoven fibrous web comprises a salt.

16. The article of claim 15, wherein the salt is selected from NaCl, CaCT. KC1, Na2 SO4, NaHCO,. NaH₂PO₄, and KA1(SO₄)2.