Advanced fabric technology and filters

Abstract

A filter material for entrapping particles and actively affecting the trapped particles within the filter. The fabric has a blend of hydrophilic superabsorbent fibers and non-superabsorbent hydrophilic fibers that is sufficiently porous as to allow gaseous flow through the fabric. The fabric having a thickness and the fabric has as a coating of a mixture of a chemically or physically active compound and a liquid carrier forming an active composition on both the outer surface of the hydrophilic superabsorbent fibers, and the hydrophilic superabsorbent fibers have a central volume also retaining the active composition. The central volume of the hydrophilic superabsorbent fibers acting as a reservoir for replacement of the active compound into the coating when concentration of active compounds in the coating are reduced to a concentration less than concentrations of the active compound within the central volume; and the liquid carrier is an aqueous liquid.

Claims

1. A method of using a flexible fabric material to provide both moisture control to a wound on a human body and antimicrobial control to a fabric material provided over the wound comprising: identifying a wound on a human body: covering the wound with the flexible fabric material comprising: a blend of hydrophilic superabsorbent fibers and non-superabsorbent hydrophilic fibers; a fabric comprising the blend such that the fabric is sufficiently porous as to allow gaseous flow of more than 10 linear ft/min at a pressure of 0.5-inch of water through the fabric; the fabric having a thickness and the fabric has as a coating of a mixture of an antimicrobially active compound and a liquid carrier forming an antimicrobial composition on the outer surface of the hydrophilic superabsorbent fibers, and the hydrophilic superabsorbent fibers have a central volume also retaining the antimicrobial composition; the coating on the hydrophilic superabsorbent fibers are present within the thickness of the fabric and on the outer surface of the hydrophilic superabsorbent fibers throughout at least 25% of the thickness of the fabric; the central volume of the hydrophilic superabsorbent fibers acting as a reservoir for replacement of antimicrobially active compound into the coating on the outer surface of the hydrophilic superabsorbent fibers when concentration of antimicrobial compounds in the coating on the outer surface of the hydrophilic superabsorbent fibers are reduced to a concentration less than concentrations of the antimicrobial compound within the central volume; and the liquid carrier is an aqueous liquid; wherein the fabric material is positioned over a portion of the human body having the wound and creating a gaseous volume between the human body and the fabric material, the fabric material controlling levels of humidity within the gaseous volume by releasing water into the volume under humidity conditions of less than 20% relative humidity in the volume when the equilibrium vapor pressure of water over the hydrophilic fibers exceeds 30% relative humidity and absorbing water from the gaseous volume into the hydrophilic superabsorbent fiber under humidity conditions of greater than 70% relative humidity in the volume when the equilibrium vapor pressure of water over the hydrophilic fibers is less than 50% relative humidity.

2. The method of claim 1 wherein the fabric with the liquid coating on the outer surface of the hydrophilic superabsorbent fibers has an initial effective pore size within the fabric and wherein increased humidity swells the hydrophilic superabsorbent fibers and reduces the initial effective pore size wherein the filter material displays an increase in particle filtration efficiency of at least 20% for particles having number average diameters of 2.2-3.0 micrometers after a change in ambient relative humidity from 20% to 50% at 20 C.

3. The method of claim 1 wherein the coating on the hydrophilic superabsorbent fibers absorbs ambient moisture to maintain the liquid coating on wet surfaces of the hydrophilic superabsorbent fibers so that particles will adhere more strongly to the wet surface formed with ambient moisture than to a dry surface of the same hydrophilic superabsorbent fibers.

4. The method of claim 1 wherein the liquid coating on the hydrophilic superabsorbent fibers is exposed to ambient moisture and the hydrophilic superabsorbent fiber absorbs ambient moisture to maintain the liquid coating on wet surfaces of the hydrophilic superabsorbent fibers so that particles having number average diameters of 2.2-3.0 micrometers will adhere more strongly to the wet surface formed with ambient moisture than to a dry surface of the same hydrophilic superabsorbent fibers.

5. The method of claim 1 wherein the fabric has an initial effective pore size within the fabric and when the fabric is exposed to increasing levels of ambient humidity, the increased levels of humidity swell the hydrophilic superabsorbent fibers and reduces the initial effective pore size.

6. The method of claim 1 wherein the liquid coating further comprises a hygroscopic material that increases a rate of absorption of ambient moisture into the liquid coating.

7. The method of claim 2 wherein the liquid coating further comprises a hygroscopic material that increases a rate of absorption of ambient moisture into the liquid coating.

8. The method of claim 3 wherein the liquid coating further comprises a hygroscopic material that increases a rate of absorption of ambient moisture into the liquid coating.

9. The method of claim 1 wherein the antimicrobially active compound comprises an antimicrobial salt, and the antimicrobial salt is retained within the liquid coating on the outer surface of the hydrophilic superabsorbent fiber to provide antimicrobial activity on a surface of the liquid coating.

10. A method of using a flexible fabric material to provide both moisture control to skin on an animal and antimicrobial control to a fabric material provided over the skin comprising: identifying an area of skin on an animal: covering the identified area of skin on the animal with the flexible fabric material comprising: a blend of hydrophilic superabsorbent fibers and non-superabsorbent hydrophilic fibers; the blend comprising a fabric comprising that is sufficiently porous as to allow gaseous flow of more than 10 linear ft/min at a pressure of 0.5-inch of water through the fabric; the fabric having a thickness and the fabric has as a coating of a mixture of an antimicrobially active compound and a liquid carrier forming an antimicrobial composition on an outer surface of the hydrophilic superabsorbent fibers, and the hydrophilic superabsorbent fibers have a central volume also retaining the antimicrobial composition; the coating on the hydrophilic superabsorbent fibers is present within the thickness of the fabric and on the outer surface of the hydrophilic superabsorbent fibers throughout at least 25% of the thickness of the fabric; the central volume of the hydrophilic superabsorbent fibers acting as a reservoir for replacement of antimicrobially active compound into the coating on the outer surface of the hydrophilic superabsorbent fibers when concentration of antimicrobial compounds in the coating on the outer surface of the hydrophilic superabsorbent fibers is reduced to a concentration less than concentrations of the antimicrobial compound within the central volume; and the liquid carrier is an aqueous liquid; wherein the fabric material is positioned over the identified portion of skin on the animal, creating a gaseous volume between the identified area of skin on the animal and the fabric material, the fabric material controlling levels of humidity within the gaseous volume by releasing water into the volume under humidity conditions of less than 20% relative humidity in the volume when the equilibrium vapor pressure of water over the hydrophilic fibers exceeds 30% relative humidity and absorbing water from the gaseous volume into the hydrophilic superabsorbent fiber under humidity conditions of greater than 70% relative humidity in the volume when the equilibrium vapor pressure of water over the hydrophilic fibers is less than 50% relative humidity.

Description

BRIEF DESCRIPTION OF FIGURES

(1) FIG. 1 shows a garment that covers parts of the head, neck and shoulders using a woven fabric as shown in FIG. 1A.

(2) FIG. 1A shows a woven fabric with SAP fibers blended into both threads and yarns in the fabric.

(3) FIG. 1B shows an alternative woven fabric with SAP fibers blended into both threads and yarns in the fabric.

(4) FIG. 1C shows a second alternative woven fabric with SAP fibers blended into both threads and yarns in the fabric.

(5) FIG. 2 shows a gas or liquid filter material in a frame, with the filter medium comprising a non-woven fabric of materials according to the present technology.

(6) FIG. 3 shows images of fluid movement, fluid capture and fluid transfer dynamics within Medtextra non-woven fabric material according to the present technology.

(7) FIGS. 4 and 4A show a graphic representations of the data of Table 2 evidencing filtration efficiency for various particle size ranges after changes in ambient condition relative humidity between 20% and 50% at 20 C.

DETAILED DESCRIPTION OF THE INVENTION

(8) As used herein, the terms antimicrobial agent(s) or germicidal agent(s) refer to materials (e.g., elemental silver) or chemicals or other substances that either kill or slow the growth of microbes. Among the antimicrobial agents or germicidal agents in use today are antibacterial agents (which kill bacteria), antiviral agents (which kill viruses), and antifungal agents (which kill fungi). A main category of antimicrobial agents are surface disinfectants, otherwise known as biocides. The term biocides is a general term describing a chemical agent, such as a pesticide, usually broad spectrum, which inactivates living microorganisms. Because biocides range in germicidal activity, other terms may be more specific, including -static, referring to agents that inhibit growth (e.g., bacteriostatic, fungistatic, or sporistatic) and -cidal, referring to agents that kill the target organism (e.g., bactericidal, fungicidal, sporicidal, or virucidal). Biocides have multiple targets and modes of action, which for instance, may include physical disruption and permanent damage to the outer cell membrane of a bacterial microbe. Some example of useful biocide chemistries include biguanides (e.g.: chlorohexidine, alexidine, polyhexamethylene biguanide, and relevant salts thereof), halogen-releasing agents (e.g.: iodine, iodophors, sodium hypochlorite, N-halamine, etc.), stabilized oxidants such as chlorine dioxide, stabilized peroxide (e.g., urea peroxide, mannitol peroxide) metal-containing species and oxides thereof (e.g.: silver, copper, selenium, etc. either in particle form or incorporated into a support matrix such as a zeolite or polymer), sulfides (e.g., sodium metabisulfite), bis-phenols (e.g., triclosan, hexachlorophene, etc), quaternary ammonium compounds (e.g., benzalkonium chloride, cetrimide, cetylpyridium chloride, quaternized cellulose and other quaternized polymers, etc.), various naturally occurring agents (e.g., polyphenols from green or black tea extract, citric acid, chitosan, anatase TiO.sub.2, tourmaline, bamboo extract, neem oil, etc.), hydrotropes (e.g., strong emulsifiers) and chaotropic agents (e.g., alkyl polyglycosides) and synergistic combinations thereof. Depending on substrate chemistry (polyolefin vs. cellulosic-based materials) and the method of incorporation into the product (topical vs. grafting), many of the above chemistries could be used alone or in concert to achieve the final claimed product properties of interest.

(9) As used herein, the phrase broad spectrum of microorganisms, is defined to include at a minimum Gram positive and Gram negative bacteria, including resistant strains thereof, for example methicillan-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococci (VRE) and penicillin-resistant Streptococcus pneumoniae (PRSP) strains. Preferably, it is defined to include all bacteria (Gram+, Gram and acid fast strains) and yeasts such as Candida albicans. Most preferably, it is defined to include all bacteria (Gram+, Gram, and acid fast), yeasts, and both envelope and naked viruses such as human influenza, rhinovirus, poliovirus, adenovirus, hepatitis, HIV, herpes simplex, SARS, and avian flu.

(10) As used herein, the phrase results in fewer viable pathogens on a treated surface compared to an untreated control surface and the phrase prevents or minimizes the contact transfer are both defined to mean that the item in question will lead to at least a 0.5 log.sub.10 reduction in the transfer of a broad spectrum of viable microorganisms when contacting another surface as compared to an untreated control item as measured by the contact transfer protocol generally outlined in U.S. Patent Application Publication No. 2004/0151919, incorporated herein by reference with respect to the protocol, and described further in the Examples. Desirably, it leads to a reduction in viable microorganisms transfer by a factor of 1 log.sub.10. More desirably, it leads to a reduction in viable microorganisms transferred by a factor of 2 log.sub.10 or greater.

(11) A non-leaching germicidal surface is one that passes ASTM E2149-01 testing protocol entitled Standard Test Method for Determining the Antimicrobial Activity of Immobilized Antimicrobial Agents Under Dynamic Contact Conditions. The lack of a zone of inhibition with the treatment agents chosen demonstrates the active species do not leach from the treated substrate, especially into skin in contact with a surface distal from the coated or embedded antimicrobial materials. Transcutaneous transfer may occur and is allowed to occur when the skin is in actual contact with the active antimicrobial agent. In a third set of experiments different coatings were tested for their efficiency against E. coli, American Type Culture Collection (ATCC) No. 8739 with both testing methods ASTM E2149-01 (dynamic contact test) and E2180-01 (static test for hydrophilic materials, Table 3). For ASTM E2149-01 two contact time points of 2 h and 24 h were chosen as to access short and long term effects. The film containing only film composition, without the fabric or additive to the fabric showed no change in bacteria concentration for both time points. Without being bound to theory, it is believed that the mechanism is not instantaneous but rather proceeds via a slow and steady bacteria destruction keeping in mind that for the reference film a 3-log CFU/ml increase was observed in the 24 hours experiment. Hence, the antimicrobial film has not only to struggle with the initial bacteria but also has to prevail over the bacteria's growth. For the static contact test ASTM E2180-01 the bacteria concentration for film sample containing the fabric antimicrobial additives increased by a factor of ten compared to the film composition reference, which could also be a superabsorbent polymer (SAP) film or powder.

(12) As used herein, the term apparel refers to conventionally constructed wearing apparel that can be readily repositioned to overlay the mouth and nasal passages, such as turtle neck apparel, scarves, Dickies (which are turtleneck covers only, without the full upper body covering), bandanas, gators, and the like. Wraps without specific apparel structure, such as a handkerchief, patch, pocket and the like, may also be used.

(13) One of the difficulties in providing fabric materials that are resistant to the growth of microbes or which can act to reduce the spread of microbes by filtering out and killing microbes that are attempting to pass through the fabric (in a gas or liquid medium) the fabric (in a gas or liquid medium) is the ability to control the antimicrobial activity over time and area in the fabric. Additionally, the provision of colors and visual patterns in the fabric can be diminished by after application of liquids to the fabric because of dye bleaching or pigment dissolution and bleeding from the applied antibiotics, which are usually carried in a liquid solvent. The present technology assists in overcoming or reducing many of these deficiencies. The technology includes creation of a fiber or filament or yarn which can be woven into products alongside standard yarns that offer a high rate of efficacy in the killing of bacteria, virus/influenzas, fungi and other microbes before they can enter the respiratory track via nasal or oral routes. The fiber will have a constant state of mobility within its makeup. This fiber can then be interwoven with other materials into products that are used daily by the general public, but have heretofore not been viewed as a health care benefit. These will include items such as, scarves, turtleneck sweaters and shirts, burkas, medical coverings, baby blankets, etc which will now capable of offering the additional protection of being antimicrobial in addition to their normal use. The classic medical masks offer no protection to the large majority of the population that will not use them for a variety of reasons, from stigma, appearance, lack of efficacy, to fashion and comfort The use of these new fibers in the creation of apparel or wearables that offer the public an increased level of protection will also allow for the economic and social interaction of society to continue by increasing the comfort level of the public when wishing to enter a heavily occupied area, such a grocery stores, shopping malls, events, or small gatherings in homes and offices.

(14) A superabsorbent polymeric material is provided in fiber or filament form. The fibers (usually blended with other fibers to form threads or yarns or filaments, also blended to form fibers or yarns or knit directly into fine fabric may be, for example, from 0.01 to 100 decitex before addition to the other materials. SAP fibers tend not to have the tensile strength desirable for most usual fabric apparel (although some reduced tensile strength is acceptable in masks, covers and the like), and so the addition of the SAP fibers with stronger fibers is desirable. The other fibers should have a water absorbance that is less than 5% of the SAP fiber.

(15) The SAP polymer can be easily imbibed with a controlled amount of aqueous borne antimicrobial material, either as a solute, suspension, dispersion or emulsions. The SAP generally has sufficiently open pores as to allow the somewhat larger molecular antimicrobials (e.g., silver particles, iodine crystals, etc.) to be carried into the SAP polymer network. The SAP fibers are then extruded or have the antimicrobial added after extrusion. Colorant may also be added at that time of extrusion or post-extrusion processing. After formation of the SAP fibers or filaments, those fibers or filaments may be processed into fabric along with other fabric fiber and materials as non-woven, woven, knitted or other manufactured fabric.

(16) In forming threads and yarns, the individual threads may comprises from 1% to 75% of total threads in the fabric. The SAP fiber concentration in the final product should be from 1 to 50% by total weight of the fabric, 1 to 35% by total weight of the fabric or from 1 to 20% by total weight of the fabric. The antimicrobial agent in the SAP fiber or filament may be about 0.25% to 15% by weight of the SAP (solids or active liquids) and preferably is from 0.50% to 10% by weight of the SAP (solids or active liquids) in the individual SAP fibers or in the total fabric.

(17) There are definite functional advantages for having the antimicrobials in the SAP and added before final fabrication of the fabric. There is the ability to better control the overall and/or local distribution of SAP and antimicrobials in the final fabric, as the SAP-bearing threads or yarns can be distributed as desired by known manufacturing techniques, such as timed feeding or positioned feeding of the SAP-bearing threads, yarns or filaments into the manufacturing process, whether forming non-woven fabrics or knitted or woven fabrics.

(18) FIG. 1A shows a woven fabric 2 with SAP fibers 4 blended into both threads and yarns in the fabric.

(19) FIG. 1B shows an alternative woven fabric 2B with SAP fibers 4 blended into both threads and yarns in the fabric.

(20) FIG. 1C shows a second alternative woven fabric 2C with SAP fibers 4 blended into both threads and yarns in the fabric.

(21) The distribution of the SAP fibers containing the antimicrobial agents can be readily seen from these figures to be highly controllable in a final location in the fabric.

(22) Germicidal Compositions

(23) The germicidal compositions utilized may be one or more germicidal reagents. These reagents may be effective by themselves or may be combined to produce a synergistic effect that is non-additive of the individual components. These germicidal reagents may be further combined with processing aids and/or other ingredients that provide functional properties to the compositions. Exemplary germicidal compositions may be based on cationic polymers, such as quaternary ammonium compounds and polymeric biguanides, alcohols, and surfactants. Combinations of cationic polymers such as quaternary ammonium compounds (e.g., quaternary ammonium cellulose and quaternary ammonium siloxane), polymeric biguanides, surfactants, alcohols, and organic acids, such as acetic, citric, benzoic acids, may produce non-additive, synergistic systems with broad pathogen efficacy. The combinations with other germicidal compounds, surfactants, appear to improve germicidal efficacy of polymeric biguanides over treatments with that employ polymer biguanides alone. Poly-hexamethylene biguanide (PHMB) hydrochloride is an exemplary cationic biguanide that is useful for providing germicidal surface-covering assemblies. Commercially available versions of PHMB, such as under the trade names Cosmocil CQ (20 wt. % PHMB in water) or Vantocil, a heterodisperse mixture of PHMB with a molecular weight of approximately 3,000 grams/mole, are active against gram-positive and gram-negative bacteria, but may not be sporicidal. Additional active germicidal agents may include, but are not limited to, a quaternary ammonium compound, a quaternary ammonium siloxane, a polyquaternary amine; metal-containing species and oxides thereof, either in particle form or incorporated into a support matrix or polymer; halogens, a halogen-releasing agent or halogen-containing polymer, a bromo-compound, a chlorine dioxide, a thiazole, a thiocynate, an isothiazolin, a cyanobutane, a dithiocarbamate, a thione, a triclosan, an alkylsulfosuccinate, an alkyl-amino-alkyl glycine, a dialkyl-dimethyl-phosphonium salt, a cetrimide, hydrogen peroxide, 1-alkyl-1,5-diazapentane, or cetyl pyridinium chloride.

(24) Table 1 summarizes various biocides and processing aids that may be used in germicidal compositions that can be used to make the germicidal surface-covering assembly. It also lists their common chemical names or commercial names. Quaternary ammonium compounds, such as commercially available under the names of Aegis AEM 5700 (Dow Corning, Midland, Mich.) and Crodacel QM (Croda, Inc., Parsippany, N.J.), with certain surfactants such as alkyl-polyglycosides, available commercially under the name Glucopon 220 UP (Cognis Corp, Ambler, Pa.), and chitosan glycolate, available under the name Hydagen CMF and Hydagen HCMF (Cognis Corp., Cincinnati, Ohio), can significantly enhance the killing efficacy of PHMB in a synergistic fashion as will be demonstrated in the tables herein. One should note that many of the biocides described herein may be used singly or in combination in a variety of products which vary considerably in activity against microorganisms. TABLE 1 Table of Active Reagents and Processing Aids Concentration Reagent Range (wt. %) Brand or Common Name Vendor Name Polyhexamethylene biguanide (PHMB) 0.01-20 Cosmocil CQ Arch Chemicals, Inc. Norwalk, Conn. Chitosan glycolate 0.01-10 Hydagen CMF and HCMF Cognis Corp., Ambler, Pa. Octadecylaminodimethyl Trimethoxysilylpropyl 0.01-10 AEGIS AEM 5700 Dow-Corning, Ammonium Chloride Midland, Mich. N-Alkyl Polyglycoside 0.01-10 Glucopon 220 UP Cognis Corp., Ambler, Pa. PG-Hydroxyethylcellulose Cocodimonium 0.01-10 Crodacel QM Croda Inc., Chloride (Quaternary Ammonium Persipanny, N.J. CellulosicSalt) Xylitol 0.01-10 Xylitol Sigma-Aldrich, Milwaukee, Wis. 2-hydroxy-1,2,3-propanetricarboxylic acid 0.01-10 Citric Acid Hach Company Ames, Iowa Benzenecarboxylic acid 0.1-2.0 Benzoic acid Mallinckrodt Baker, Inc Phillipsburg, N.J. 2-hydroxybenzoic acid 0.01-10 Salicylic acid Mallinckrodt Baker, Inc Phillipsburg, N.J. Methane-carboxylic acid 0.01-2.0 Acetic acid Sigma-Aldrich St. Louis, Mo. 1,3-Propanedicarboxylic Acid 0.01-10 Glutaric acid Sigma-Aldrich St. Louis, Mo. Iodine 0.05-10 Iodine Sigma-Aldrich St. Louis, Mo. Ethyl Hydroxyethyl cellulose 0.01-5.0 Bermocoll EBS 481 FQ Akzo Nobel, Inc., (E 481) Stamford, Conn. Polyvinyl pyrrolidone 0.01-10 Plasdone K90 ISP Technologies, Inc., Wayne, N.J. Poly(vinyl pyrrolidone-co-vinyl acetate) 0.01-10 PVP/VA S-630 ISP Technologies, Inc., Wayne, N.J. Polyvinyl pyrrolidone-Iodine complex 0.01-10 PVP-Iodine ISP Technologies, Inc., Wayne, N.J. Guanidine Hydrochloride and Sorbitol 0.01-5.0 Nicepole FL NICCA USA, Inc. Fountain Inn, S.C. Acrylic Co-Polymer Compound and Isopropyl 0.01-5.0 Nicepole FE 18U NICCA U.S.A., Inc. Alcohol Fountain Inn, S.C. 25% Copper oxide (CuO, Cu.sub.2O) 0.01-20.0 Cupron, Cupron, Inc. (CAS #1317-39-1), 75% polypropylene Greensboro, N.C. (PP) resin Silver Sodium Hydrogen Zirconium 0.01-20.0 AlphaSan RC 2000* Milliken, Phosphate Spartanburg, S.C. Silver Zinc glass (70-100%) barium sulfate 0.01-20.0 Irgaguard B 7520 Ciba Specialty Chemicals Corp. (1-30%), PP resin (10-30%) Tarrytown, N.Y. These additives have been typically compounded in thermoplastic # resins (e.g., polypropylene (PP)) to produce a concentrate which is then dry blended with the # virgin resin and co-extruded to produce fibers and webs containing such additives.

(25) These polymeric structure formats are a problem according to the technology in use. The present invention requires the materials to be in a carrier that can be sufficiently wetted by moisture vapor from exhalation so that the surface of the substrate is moist or even liquid, as with lower molecular weight hydrophilic or even aqueous-soluble polymers such as polyvinyl alcohols (10,000 to 50,000 number average molecular weight), polyvinylidene chloride (9,000 to 50,000 number average molecular weight) Concentration of the antimicrobial additive should be on the surface of the carrier even though this depends on several factors including additive concentration in the melt relative to the main body of resin or type of resin, processing/application conditions and thermal history, etc.

(26) In certain embodiments the germicidal composition includes combinations of biocide active agents that work against both bacteria and viruses. For instance, a composition may include: PHMB, quaternary ammonium cellulose, xylitol, citric acid, benzoic acid, surfactant, complexing agent (e.g., PVP), and/or antistatic agent (e.g., Nicepole FL). A desirable antistatic agent is one that does not reduce surface tension of water by more than 20 dynes/cm. The present composition desirably is moderately hydrophilic; hence, a droplet of a formulation applied to a surface can produce a contact angle of less than about 90 with respect to, for example, a polypropylene substrate surface. The compositions have a pH in a range of about 2 to about 5 or 6. Preferred pH ranges are about 2.5-4, or 2.5-3.5, depending on the desired, particular environmental conditions for use. The compositions may also contain an acrylic co-polymer compound and isopropyl alcohol, which serves as an antistatic agent useful for treating nonwoven fabrics such as those commonly found in medical fabrics.

(27) A germicidal solution may contain a primary microbial active agent, for example, 0.1-99.9 wt % polyhexamethylene biguanide (PHMB) by weight of active agents, and a secondary active agent selected from at least one of the following: alkyl polyglycosides, quaternized cellulose derivatives, quaternized siloxanes, surfactants, and organic acids. The final concentration for each of the active reagent and processing aids on a treated substrate can range from about 0.01-20 wt %. The exact concentrations may depend on the specific kind of microorganism that one is targeting against and/or the nature of the coated substrate material.

(28) The germicidal composition may be odorless to humans; that is, the composition is undetectable at least to the human olfactory system. This characteristic is important if the germicidal composition is to be used on face masks and other substrates that come into close proximity to the human nose.

(29) Substrates

(30) The apparel substrates used in the practice of the present technology must be porous enough to allow wearers to breathe through the fabric without excessive air flow being drawn parallel to the surface of the fabric in the apparel. Otherwise the air would be drawn around, rather than through, the apparel. This is another advantage of using a repositionable fabric apparel element such as a turtle neck. The neck may be pulled over the lower portions of the face and adjusted easily into a comfortable position that best control flow through, and not around the fabric. Generally speaking, the treated surface of the germicidal surface-covering assembly would be outward or exterior facing and away from the skin-contacting surface such as a lining of a garment or article, although internal compositions work well also. The purpose of this orientation is to address the indirect transmission or the contact transfer of pathogens.

(31) The material may have a natural and significant elasticity, or may be a material with low elastic stretchability or memory, such as a tightly woven fabric with less than 5% elastic elongation or a loosely woven fabric with 15-20% elongation in at least one direction. The elongation may also be created by the elastic nature of the fabric composition itself or by added elements such as elastic edges or inserts. Taughtness in an applied position may be also provided in whole or in part by fabric closure systems such as ties, belts, velour and crochet (e.g., Velcro attachments) and adhesive.

(32) Generally speaking, nonwoven materials treated with the germicidal compositions may even largely maintain their liquid barrier properties when segregated to the surface of the materials, as the moisture flow through the fabric may wet or moisten the carrier (which is preferably in addition to the fabric structural material) and acts as a moisture holder or even liquid/pasty film forming layer actively supporting and presenting the antimicrobial agent. It is believed that by means of controlling the topical placement of the antimicrobial composition, in which the agents are confined to the outermost or top spunbond layer of a substrate, for instance, one can enhance the creation of a liquid conduit or liquid support in the layers of the substrate material, thereby achieving the beneficial combination of retention of particles (e.g., viruses) and germicidal properties. In addition, placing the germicidal chemistry on the surface of the substrate will make the biocides more readily available to interact with pathogens, thus improving overall efficacy.

(33) Process Methods

(34) The germicidal compositions can be applied topically to the external surfaces of the fabric, which may be knitted, woven or nonwoven web filaments, yarns or final fabrics after they are formed. Desirably, an even, but not necessarily exactly uniform coating is applied over the substrate surfaces. The coating has a relatively even distribution over or within the treated substrate surface. Any processing aid may evaporate or flash off once the germicidal composition dries on the substrate surface, but the coated composition must or should retain its hydrophilic and even hygroscopic ability so that a liquid or floating layer that attracts and holds particles is formed on fabric internal and/or external surfaces. Suitable processing aids may include alcohols, such as isopropanol, butanol, hexanol or octanol.

(35) The active compositions should comprise as a single layer or blended layer or combinations of layers at least the antimicrobial agent, a water-absorbing or water-holding component (WHA), a surfactant, and other possible ingredients. It is preferred that the WHA be hygroscopic, a term understood in the art as requiring that the material active withdraw moisture from air in contact with the material. Materials such as commercially available super-absorbent polymers, humectants, hygroscopic salts (particularly in water soluble polymers), glycerine, viscous sugar solutions (mannitol, rabbitol included as higher molecular weight, less volatile sugar solutions), and the like.

(36) The materials described herein may be part of or the entirety of materials used as clothing, coverings (e.g., wraps and blankets, sheets, pillow cases, surgical drapes, equipment such as backpacks, hoods, jackets, shirts, dental tray covers, sheets on trays for carrying or supporting devices that should be kept free of active microbes, and the like) and articles.

(37) According to an embodiment, the antimicrobial composition(s) and associated materials in the same or adjacent layer can be applied to the material substrate via conventional saturation processes such as a so-called dip and squeeze or padding technique. The dip and squeeze or padding process can coat both sides of and/or through the bulk of the substrate with the germicidal composition. When dipped in a bath, the germicidal solution be a unitary medium containing all components, or in subsequent multiple step processing, other desired components may be later added to the base germicidal layer. For instance, a formulation of a unitary germicidal solution may include leveling and/or antistatic agents. On substrates containing polypropylene, an antistatic agent can help dissipate static charge build-up from mechanical friction. An antistatic agent can be added to the germicidal solution, and the mixture can be introduced simultaneously to the material substrate in one application step. Alternatively, the antistatic solution can be applied using a spray after the germicidal solution in a second step. The antimicrobial material may also be dusted over a wet carrier layer on the substrate and that will fix the antimicrobial on the surface.

(38) In certain product forms, where one wishes to treat only a single side and not only the inner layers that make up a fabric substrate or opposing side of the sheet substrate, in which the substrate material any layered to another sheet ply (e.g., filter or barrier media) that is without the antimicrobial treatment, other processes are preferred such as at rotary screen, reverse roll, Meyer-rod (or wire wound rod), Gravure, slot die, gap-coating, or other similar techniques, familiar to persons in the printing and textile industry. Also one may consider printing techniques such as flexographic, ink jet, bubble jet or digital techniques. Alternatively one may use a combination of more than one coating to achieve a controlled placement of the treatment composition. Such combination may include, but not limited to, a reverse Gravure process followed by a Meyer rod process. Alternatively, the germicidal composition may be applied through an aerosol spray on the substrate surface. The spray apparatus can be employed to apply the germicidal solution and/or antistatic agent only on one side of the substrate sheet or on both sides separately if desired. An antistatic agent can be applied to the substrate in a secondary step, for example, using a spray system or any other conventional application process.

(39) Various other methods may be employed for contacting and/or creating or attached to a substrate(s) with the treatment composition or compositions in accordance with the invention. For example, a substrate may be printed on by means of print rolls or other coating steps, or spray techniques may be employed. Preferably, the treatment composition or compositions are applied as an overlayer onto the substrate by a Meyer rod, reverse Gravure or flexographic techniques, for example, in such a way that the treatment composition forms a uniform and homogeneous layer on top of the substrate with minimum penetration of the treating composition into the bulk of the substrate. The overlayer coating, in general, results in more uniform distribution of the anti-microbial treatment on the substrate and permits the anti-microbial agent(s) to be more readily available on the surface of the substrate, although it is preferred to have the antimicrobial material distributed with its carrier throughout the apparel fabric to provide greater surface area for catching and holding the virus particles.

(40) Germicidal Test Method

(41) A. Sample Preparation

(42) Test organisms are grown in 25 mL appropriate broth medium for about 242 hours at 372 C. in a orbital shaker. The bacterial culture is then transferred by placing about 100.mu.L aliquot in 25 mL of broth and grown again for about 242 hours at 372 C. The organisms are then centrifuged and washed three times with phosphate buffered saline (PBS). The organisms are then suspended in PBS to obtain an inoculum of approximately 1.10.sup.8 CFU/mL.

(43) The test articles and control swatches are exposed to an ultraviolet light source for about 5-10 minutes per side before testing to assure that the swatches are sanitized prior to inoculation with the bacteria. The test materials are brought into contact with a known population of test bacteria from the inoculum for a specified period of time. A sample is then plated at the end of the exposure time to enumerate the surviving bacteria. The log.sub.10 reduction from the control material and the original population is calculated using the following formula: Log.sub.10 Control*Log.sub.10 CFU/swatch Test Article=Log.sub.10 Reduction*CFU/swatch from control swatches or theoretical CFU/swatch.

(44) After exposing the bacteria to the surface of a treated product for a designated amount of time (40 seconds), the substrate is placed in a flask and a buffer solution is added to elute the microorganisms off the substrate prior to plating them to see how many are left alive. This buffer solution contains a chemical to de-activate or neutralize the germicidal agent to (a) stop the active agent from killing the organisms after the designated time period and (b) to prevent artifacts that may arise from exposing the microorganisms to the germicidal in solution rather than solely on the substrate. The neutralizer is pre-screened to make sure that they do not affect the microorganisms. The neutralizer employed may be selected from a list that is commonly used in the field. These include non-ionic detergents, Bisulphate, lecithin, Leethen broth, thiosulfate, thioglycollate, and pH buffers. Method similar to those described in American Society for Testing and Materials, Standard Practices for Evaluating Inactivators of Germicidal Agents Used in Disinfectant, Sanitizer, Antiseptic, or Preserved Products, Amer. Soc. Testing Mat. E 1054-91 (1991) can be used.

(45) B. Contact Transfer Protocol

(46) The following generalized discussion relates to a method for determining viable microbe transmission levels or contact transfer of microbes from one contaminated article to at least one other article. Generally speaking, the method includes applying an inoculum including a microbe to a first surface, contacting a transfer substrate to the first surface, extracting the transferred inoculum from the transfer substrate, permitting the extracted inoculum to incubate, and quantifying the microbe level to determine a percent recovery. As used herein, inoculum refers to any material containing at least one microbe that may act as a source of infection in a host.

(47) The method may be used to measure viable contact transfer of various microbes, including, for example, Aspergillus niger (American Type Culture Collection (ATCC) No. 16404), Candida albicans (ATCC No. 10231), Hepatits A HM175/18f (ATCC No. VR-1402), Herpes simplex virus 1 GHSV-UL46D (ATCC No. VR-1545), Acinetobacter baumannii (ATCC No. 15149), Clostridium difficile (ATCC No. 43594), Enterobacter cloacae (ATCC No. 29249), Enterococcus faecalis (ATCC No. 51299), Enterococcus faecium (ATCC NO. 700221), Enterococcus hirae (ATCC No. 10541), Escherichia coli (ATCC No. 13706), Escherichia coli (ATCC No. 31705), Mycobacterium smegmatis (ATCC No. 10143), Mycobacterium tuberculosis (ATCC 27294), Pseudomonas aeruginosa (ATCC No. 9027), Pseudomonas aeruginosa (ATCC No. 27853), Staphylococcus aureus (ATCC No. 6538), Staphylococcus aureus (ATCC No. 33592), Staphylococcus epidermidis (ATCC No. 12228), and Staphylococcus epidermidis (ATCC No. 51625).

(48) After the desired microbe is selected, an inoculum is prepared by diluting a stock culture of the microbe. The culture may be diluted to any desired level using a sterile buffered liquid, and in some instances, may be diluted to an inoculum level of from about 110.sup.6 colony forming units (CFU)/ml to about 310.sup.6 CFU/ml. However, for the present testing, the inoculum level was 510.sup.8 CFU/ml. Prior to performing the evaluation, a sterile buffer solution may be prepared for later use. The buffer solution may be replaced about every two months. In some instances, the buffer solution may be sterile phosphate buffered water. The desired inoculum is then placed aseptically onto a first surface. Any quantity of the desired inoculum may be used. However, for the contact transfer testing of the germicidal surface-covering assembly, a quantity of about 0.5 ml is applied to the first surface. Furthermore, the inoculum may be applied to the first surface over any desired area. In some instances, the inoculum may be applied over an area of about 7 inches (178 mm) by 7 inches (178 mm). However, in the present testing, the inoculum is applied to substantially all of a 4 inch (101 mm) by 4 inch (101 mm) square piece of material that constitutes the first surface.

(49) The innoculum is then permitted to remain on the first surface for a relatively short amount of time. For example, about 20 seconds before the article to be evaluated, i.e., the transfer substrate is brought into contact with the first surface.

(50) The transfer substrate may be any apparel as defined herein that is worn about the head (bandana, headband, etc,) or neck (scarf, Dickie or turtleneck apparel. Masks may also be used, but the apparel is an approved embodiment as it may be repositioned from its normal use.

(51) The solution on the sample plates may then be incubated for a desired amount of time to permit the microbes to propagate. In some instances, the solution may incubate for at least about 48 hours. The incubation may take place at any optimal temperature to permit microbe growth, and in some instances may take place at from about 33 C. to about 37 C. In some instances, the incubation may take place at about 35 C. After incubation is complete, the microbes present are counted and the results are reported as CFU/ml. The percent recovery may then be calculated by dividing the extracted microbes in CFU/ml by the number present in the innoculum in (CFU/ml), and multiplying the value by 100.

(52) The technology included herein also include a method for the manufacture of a fabric having antimicrobial activity with steps that might include: a) providing a superabsorbent polymer composition; b) associating an antimicrobial composition into the superabsorbent polymer composition to form a final composition; c) extruding the final composition to form active fibers or active filaments; d) blending the active fibers or active filaments with textile fibers or textile filaments to form a textile blend; and e) fabricating the textile blend to form a final fabric material having antimicrobial activity.

(53) The antimicrobial composition preferably comprises a quaternary ammonium salt and may further comprises a humectant. Fabricating the textile blend may comprise forming a non-woven fabric comprising the textile blend. The textile blend may be distributed with at least 20% by weight higher concentrations of the textile blend in some areas of the final fabric material than other areas of the final fabric material so that there is greater antimicrobial activity in some areas of the final fabric material than in other areas. The fabricating of the textile blend may includes weaving or knitting a final fabric comprising the textile blend.

(54) The present invention has been described in general and in detail by way of examples. The words used are words of description rather than of limitation. Persons of ordinary skill in the art understand that the invention is not limited necessarily to the embodiments specifically disclosed, but that modifications and variations may be made without departing from the scope of the invention as defined by the following claims or their equivalents, including other equivalent components presently known, or to be developed, which may be used within the scope of the present invention. Therefore, unless changes otherwise depart from the scope of the invention, the changes should be construed as being included herein and the appended claims should not be limited to the description of the preferred versions herein.

(55) Superabsorbent fibers can help the filter media produce equivalent filtration efficiency while reducing thickness and air resistance. As FIG. 3 shows, the filter media with higher amounts of superabsorbent fiber can provide equivalent filtration efficiency with lower pressure drop and thinner media, or higher filtration efficiency with similar pressure drop.

(56) TABLE-US-00001 TABLE 1 Pressure Drop of Medtextra Fabrics Media Grades Media Grade Basis dP (mm H2O) Weight % @20% @50% (gsm) SAF RH RH 100 2.4% 1.2 2.4 30 4.0% 0.5 1.6 52 4.6% 0.8 2.0 75 4.8% 1.5 2.6 80 3.0% 1.7 2.9 139 5.2% 3.1 4.4

(57) TABLE-US-00002 TABLE 2 Penetration Values (1-Efficiency) Basis Wt. 100 GSM 52 GSM 75 GSM SAP 2.40% 4.60% 4.80% Rel. Humidity % % % Overall Particle Size 20% 50% Improved 20% 50% Improved 20% 50% Improved AVG 1.6-2.2 100.0% 83.5% 16.5% 100.0% 83.4% 16.6% 100.0% 81.1% 18.9% 17% 2.2-3.0 100.0% 70.8% 29.2% 100.0% 71.8% 28.2% 100.0% 67.0% 33.0% 30% 3.0-4.0 88.7% 59.9% 32.5% 100.0% 62.5% 37.5% 87.9% 53.8% 38.8% 36% 4.0-5.5 75.8% 58.8% 22.5% 86.5% 62.3% 28.0% 70.8% 52.9% 25.3% 25% 5.5-7.0 73.0% 58.5% 19.8% 86.2% 63.8% 26.0% 66.9% 52.8% 21.0% 22% 7.0-10.0 52.8% 42.2% 20.1% 72.8% 49.5% 32.1% 49.9% 38.4% 23.0% 25% AVG .sup.23% .sup.28% .sup.27% 26% particle size in microns

(58) When compared to the 100-gsm media with 2.4% superabsorbent fiber, equivalent filtration efficiency is achieved for 1.6-3.0 micron particles using the 52-gsm media with 4.6% superabsorbent fiber. In this case, a small increase in superabsorbent fiber allows for an almost 50% reduction in overall fiber use. In addition, the air resistance seen for the 52-gsm media was 2.03-mm of water while the air resistance for the 100-gsm prototype was 2.4-mm of water, almost 20% higher. When the overall basis weight is increased from 52-gsm to 75 gsm, superior [0095] When compared to the 100-gsm media with 2.4% superabsorbent fiber, equivalent filtration efficiency is achieved for 1.6-3.0 micron () particles using the 52-gsm media with 4.6% superabsorbent fiber. In this case, a small increase in superabsorbent fiber allows for an almost 50% reduction in overall fiber use. In addition, the air resistance seen for the 52-gsm media was 2.03-mm of water while the air resistance for the 100-gsm prototype was 2.4-mm of water, almost 20% higher. When the overall basis weight is increased from 52-gsm to 75-gsm, superior filtration efficiency is achieved at all particle sizes when compared to the 100-gsm media. This higher efficiency is achieved with an air resistance of 2.6 mm of water compared to an air resistance of 2.4-mm of water with the 100-gsm media. Testing was performed using a linear air velocity of 30 ft/min.

(59) In these cases, the substitution of superabsorbent fibers also leads to a lower material cost because the small cost increase in the additional superabsorbent fiber is more than offset by the reduction in overall fiber use.

Tables 3 A and B: Efficiency at 20% Relative Humidity

(60) TABLE-US-00003 TABLE 3A Superabsorbent % 2.40% 4.60% 4.80% Basis Wt. Particle Size 100 52 75 () (GSM) (GSM) (GSM) 1.6-2.2 0.00% 0.00% 0.00% 2.2-3.0 0.00% 0.00% 0.00% 3.0-4.0 11.32% 0.00% 12.14% 4.0-5.5 24.18% 13.50% 29.19% 5.5-7.0 27.03% 13.84% 33.10% 7.0-10.0 47.21% 27.18% 50.09%

(61) TABLE-US-00004 TABLE 3B Efficiency at 50% Relative Humidity Superabsorbent % 2.40% 4.60% 4.80% Basis Wt. Particle Size 100 52 75 (microns) GSM GSM GSM 1.6-2.2 16.46% 16.59% 18.88% 2.2-3.0 29.20% 28.17% 33.04% 3.0-4.0 40.11% 37.52% 46.21% 4.0-5.5 41.25% 37.68% 47.11% 5.5-7.0 41.47% 36.25% 47.16% 7.0-10.0 57.81% 50.53% 61.59%

(62) According to Tables 3 and 4, MedTextra non-woven fabric as described in the examples has demonstrated increased air filtration efficiency as foreseen by its inventors in these lab tests of various prototypes using industry-testing protocols. The prototypes varied in basis weight in grams per square meter and the percentage of fibers by weights that were SAP vs. the structural fibers.

(63) On average, over three tested prototypes with different specifications, penetration rates (rates at which particles penetrate through the fabric) declined by 26%. This is the same as increasing the efficiency rate by about 50%.

(64) The data shows that higher the SAP percentage then the higher the improvement in filtration efficiency. When SAP percentage about doubled, then the filtration improvement increased by about 21%. At some particle size ranges the improvement was higher than the average, hitting 36% across the three media. The lowest improvement was 16.5% and the highest 38.8% at the individual prototype and particle class level. So the improvement is across particle sizes and media specifications.

(65) FIG. 2 shows a gas or liquid filtration system 300 having Medtextra non-woven fabric material 302 in a rigid frame 304, with the filter medium 302 comprising a non-woven fabric of materials according to the present technology. Direction of air flow 306 is shown. An important aspect of the present technology to be understood from the images in FIG. 3, which is the ability of the non-woven fabric material in the Medtextra fabric media face mask dynamic image to respond to changes in humidity. This enables the fabric to respond to changes in humidity (as when air flow from humid sources, which are more likely to contain particulate contaminants, is initiated or increased across the fabric material). With increased humidity (as with increased effluents, or increased sneezing), pore size decreases to assure greater degrees of particle capture. Therefore, when the fabric is used as a face mask, the fabric responds to conditions of the user as where exposed to moisture droplets in the air from others, or from moisture droplets being emitted by the wearer. The humidity affecting the diameter of the fibers during swelling and the pore size which is directly affected by the diameters of the fibers can be ambient humidity or local humidity altered by the wearer. Increased swelling of the SAP fibers (which also tend to act as reservoirs for active materials) causes the pore size to decrease and to cause an increase in active surface area containing the active ingredients by expansion of the fiber diameter (therefore expanding the surface area with actives thereon).

(66) In the portion of FIG. 3 wherein the cross-section of the SAP fiber within the Medtextra fabric is shown, three areas of importance and their functions are identified. The centermost area of the fiber referred to as the SAP water reservoir retains water and a relatively high (as compared to the outermost darker solution layer.) concentration of actives as compared to an outermost solution layer where the antimicrobials or other actives are also carried. When liquid (with actives) is initially applied to the SAP fiber (e.g., during dipping, spraying or coating of the fabric material with an actives-containing solution), the concentration of actives in the centermost water reservoir area and the darker liquid active solution area outermost on the SAP fiber will be approximately the same and the concentration of actives will be in relative equilibrium. As actives are used in or removed from (e.g., evaporation, chemical reaction, or other functional exhaustion of the chemistry), the centermost reservoir area concentration of actives subsequently then has a higher concentration of actives. This higher concentration of actives in the interior of the fiber creates a driving force (because of the inequality) that causes a mass transfer of compounds in greater concentration in the centermost layer of the SAP into the liquid outermost surface solution layer on the fiber.

(67) A functional operation of the SAP fibers within the fabrics of the present technology is that, where actives are not reapplied, the central area of the SAP fibers acts as a reservoir for active ingredients, replacing exhausted or otherwise diminished amounts of actives in a liquid surface layer of a solution of the actives with additional actives in an attempt to keep an equilibrium balance of concentrations of an active in both the liquid solution coating on the SAP fibers and the central reservoir volume within the SAP fibers. This effect prolongs a high level of active life for actives on the surface of the SAP fibers, where such actives interact the most with fluid passing through the fabric and with particles adsorbed onto the liquid coating on the surface of the SAP fibers.

(68) Additionally, and especially with smaller trapped particles, eddies in the outer liquid layer on the surface of the SAP fibers tend to embed the small particles into at least the outer volume of the SAP fiber material. This both assist in assuring that such trapped particles are not re-released, but also that the trapped particles are in intimate, active contact with the actives in the liquid layer and additional actives migrating from the centermost volume of the SAP fibers.

(69) The technology may therefore be further described as a filter material for entrapping particles and actively affecting the trapped particles within the filter having: a blend of hydrophilic superabsorbent fibers and non-superabsorbent fibers; the blend being at least a fabric that is sufficiently porous as to allow gaseous flow through the fabric at a pressure of 3 pounds per square inch; the fabric having a thickness and the fabric has as a coating of a mixture of an antimicrobially active compound and a liquid carrier forming an antimicrobial composition on both the outer surface of the hydrophilic superabsorbent fibers, and the hydrophilic superabsorbent fibers have a central volume also retaining the antimicrobial composition; the coating on the hydrophilic superabsorbent fibers are present within the thickness of the fabric and on the hydrophilic superabsorbent fibers throughout at least 25% of the thickness of the fabric; the central volume of the hydrophilic superabsorbent fibers acting as a reservoir for replacement of antimicrobially active compound into the coating when concentration of antimicrobial compounds in the coating are reduced to a concentration less than concentrations of the antimicrobial compound within the central volume; and the liquid carrier is an aqueous liquid.

(70) The non-superabsorbent fibers can be hydrophobic or hydrophilic. The filter material may have an initial effective pore size within the fabric and wherein increased humidity swells the hydrophilic superabsorbent fibers and reduces the initial effective pore size. The coating on the hydrophilic superabsorbent fibers may absorb ambient moisture to maintain the coating on wet surfaces of the hydrophilic superabsorbent fibers so that particles will adhere more strongly to the wet surface formed with ambient moisture than to a dry surface of the same hydrophilic superabsorbent fibers. The coating may further have a hygroscopic material. The filter material may be a garment such as a mask, scarf, veil, or other typical garment and may be a wound dressing, bandage, wrap or body cover shaped (or not, as with a strip of fabric, sheet of fabric, and the like) to fit over a portion of a human body. The filter material may be positioned over a portion of the human body creating a gaseous volume between the human body and the filter material, the filter material controlling levels of humidity within the gaseous volume by releasing water into the volume under humidity conditions of less than 50% relative humidity in the volume when the equilibrium vapor pressure of water over the hydrophilic fibers exceeds 50% relative humidity and absorbing water from the gaseous volume into the hydrophilic superabsorbent fiber under humidity conditions of greater than 70% relative humidity in the volume when the equilibrium vapor pressure of water over the hydrophilic fibers is less than 50% relative humidity.

(71) The present technology also includes a method for providing both moisture control to a wound on an animal and antimicrobial control to a fabric material provided over the wound in which there may be steps of: identifying a wound on an animal; covering the wound with a flexible fabric material having at least: a blend of hydrophilic superabsorbent fibers and non-superabsorbent fibers; the blend comprising a fabric that is sufficiently porous as to allow gaseous flow of more than 10 linear ft/min through the fabric at a pressure of 0.5-inch of water (125 Pa); higher pressure may also be used, especially with liquid flow through filters such that pressure of >0.5 psi, >1 psi, >5 psi, >8 psi; >10 psi; >12 psi; >15 psi and higher may be used; the fabric having a thickness and the fabric has as a coating of a mixture of an antimicrobially active compound and a liquid carrier forming an antimicrobial composition on both the outer surface of the hydrophilic superabsorbent fibers, and the hydrophilic superabsorbent fibers have a central volume also retaining the antimicrobial composition; the coating on the hydrophilic superabsorbent fibers are present within the thickness of the fabric and on the hydrophilic superabsorbent fibers throughout at least 25% of the thickness of the fabric; the central volume of the hydrophilic superabsorbent fibers acting as a reservoir for replacement of antimicrobially active compound into the coating when concentration of antimicrobial compounds in the coating are reduced to a concentration less than concentrations of the antimicrobial compound within the central volume; and the liquid carrier is an aqueous liquid; wherein the fabric material is positioned over a portion of the human body creating a gaseous volume between the human body and the filter material, the filter material controlling levels of humidity within the gaseous volume by releasing water into the volume under humidity conditions of less than 20% relative humidity in the volume when the equilibrium vapor pressure of water over the hydrophilic fibers exceeds 30% relative humidity and absorbing water from the gaseous volume into the hydrophilic superabsorbent fiber under humidity conditions of greater than 70% relative humidity in the volume when the equilibrium vapor pressure of water over the hydrophilic fibers is less than 50% relative humidity. The relative humidity variations may vary by design from product to product. The method is preferably practiced with the above described filter materials wherein the fabric has an initial effective pore size within the fabric and wherein increased humidity swells the hydrophilic superabsorbent fibers and reduces the initial effective pore size, or wherein the coating on the hydrophilic superabsorbent fibers absorbs ambient moisture to maintain the coating on wet surfaces of the hydrophilic superabsorbent fibers so that particles will adhere more strongly to the wet surface formed with ambient moisture than to a dry surface of the same hydrophilic superabsorbent fibers. The filter material can display an increase in particle filtration efficiency of at least 20% (at least 25%, at least 30% and even at least 40% or more) for particles having number average diameters of 2.2-3.0 micrometers after a change in ambient relative humidity from 20% to 50% at 20 C.

(72) A more general description of the present technology includes a filter material for entrapping particles and actively affecting the trapped particles within the filter having: a blend of hydrophilic superabsorbent fibers and non-superabsorbent hydrophilic fibers; the blend comprising a fabric that is sufficiently porous as to allow gaseous flow through the fabric at a pressure of 3 pounds per square inch; the fabric having a thickness and the fabric has as a coating of a mixture of a chemically or physically active compound (e.g., antioxidant, free radical scavenger, oxidant, perfume, chelating agent, antistatic agent, etc.) and a liquid carrier forming an active composition on both the outer surface of the hydrophilic superabsorbent fibers, and the hydrophilic superabsorbent fibers have a central volume also retaining the active composition; the coating on the hydrophilic superabsorbent fibers are present within the thickness of the fabric and on the hydrophilic superabsorbent fibers throughout at least 25% of the thickness of the fabric; the central volume of the hydrophilic superabsorbent fibers acting as a reservoir for replacement of the active compound into the coating when concentration of active compounds in the coating are reduced to a concentration less than concentrations of the active compound within the central volume; and the liquid carrier is an aqueous liquid.