Silver-containing antimicrobial articles and methods of manufacture

Abstract

A silver composition comprising silver sulfate, methods of making antimicrobial articles, particularly packaged antimicrobial articles, methods of whitening antimicrobial articles, and packaged antimicrobial articles.

1 . A method of making a packaged antimicrobial article, the method comprising: 
 preparing a composition comprising silver sulfate;    coating the silver sulfate composition on a substrate;    drying the coated substrate to form an antimicrobial article;    placing the antimicrobial article in packaging material having a volatile organic content of no greater than 100 mg per square meter; and    sealing the packaging material with the antimicrobial article therein.    
     
     
         2 . The method of  claim 1  further comprising irradiating the antimicrobial article after the packaging material is sealed.  
     
     
         3 . The method of  claim 2  wherein irradiating comprises irradiating with gamma radiation and/or electron beam radiation.  
     
     
         4 . The method of  claim 2  wherein drying the coated substrate occurs at a temperature that causes the silver sulfate composition to develop a color other than a whitish color, and further wherein the antimicrobial article is color stable after irradiation.  
     
     
         5 . The method of  claim 1  wherein the substrate is a silver nitrate oxidizable substrate.  
     
     
         6 . The method of  claim 5  wherein drying the coated substrate occurs at a temperature that causes the silver sulfate composition to develop a yellowish color due to the formation of silver in the zero valence state, and further wherein the antimicrobial article is color stable after irradiation.  
     
     
         7 . The method of  claim 1  wherein the substrate comprises a cellulosic material.  
     
     
         8 . The method of  claim 6  wherein the substrate comprises cotton.  
     
     
         9 . The method of  claim 1  wherein the substrate is a nonwoven gauze, a woven gauze, a porous film, a nonporous film, a knitted fabric, a foam, or a hydrocolloid.  
     
     
         10 . The method of  claim 1  wherein the substrate comprises a material selected from the group consisting of polyester, nylon, polyethylene, polypropylene, polyacrylonitrile, polyvinylidene difluoride, polytetrafluoroethylene, polyoxymethylene, polyvinyl chloride, polycarbonate, styrene-ethylenebutylene-styrene elastomer, styrene-butylene-styrene elastomer, styrene-isoprene-styrene elastomer, and combinations thereof.  
     
     
         11 . The method of  claim 1  wherein drying the coated substrate occurs at a temperature of less than 190 ° C.  
     
     
         12 . The method of  claim 1  wherein stabilizing agents are present in the composition in an amount of less than 100 ppm.  
     
     
         13 . The method of  claim 1  wherein the antimicrobial article is maintained in an environment of no more than 50% RH at room temperature.  
     
     
         14 . The method of  claim 13  wherein the antimicrobial article is maintained in an environment of no more than 30% RH at room temperature.  
     
     
         15 . The method of  claim 14  wherein drying the coated substrate occurs at a temperature that causes the silver sulfate composition to develop a color other than a whitish color, and further wherein the antimicrobial article is color stable during and after irradiation.  
     
     
         16 . The method of  claim 1  wherein drying the coated substrate occurs at a temperature that causes the silver sulfate composition to develop a whitish color, further wherein activated carbon is present in the packaging, and further wherein the antimicrobial article is color stable during and after irradiation.  
     
     
         17 . The method of  claim 1  wherein the packaging material has an oxygen permeability of less than 0.01 cubic centimeter per 645 square centimeters per 24 hours.  
     
     
         18 . The method of  claim 1  wherein the packaging material has a moisture vapor transmission rate of less than 0.01 gram per 645 square centimeters per 24 hours.  
     
     
         19 . The method of  claim 1  wherein the silver sulfate composition further comprises silver compounds other than silver sulfate.  
     
     
         20 . The method of  claim 19  wherein the silver compounds are selected from the group consisting of silver oxide, silver nitrate, silver acetate, silver citrate, silver chloride, silver lactate, silver phosphate, silver stearate, silver thiocyanate, silver carbonate, silver saccharinate, silver anthranilate and combinations thereof.  
     
     
         21 . The method of  claim 1 , further comprising silver metal.  
     
     
         22 . The method of  claim 20  wherein silver in the zero-valent state comprises less than 20 wt % of the composition based on the total weight of the silver compounds of the composition.  
     
     
         23 . The method of  claim 1  wherein the silver sulfate is present in an amount of at least 60 wt % of the composition based on the total weight of the silver compounds of the composition.  
     
     
         24 . The method of  claim 1  wherein the silver sulfate composition is essentially free of any acid.  
     
     
         25 . A packaged antimicrobial article made by the method of  claim 1 .  
     
     
         26 . A packaged antimicrobial article, comprising: 
 an antimicrobial article comprising a substrate coated with a silver sulfate composition; and    packaging having the antimicrobial article sealed therein;    wherein the packaging comprises material having a volatile organic content of no greater than 100 mg per square meter.    
     
     
         27 . The packaged article of  claim 26  wherein the silver compounds are selected from the group consisting of silver oxide, silver nitrate, silver acetate, silver citrate, silver chloride, silver lactate, silver phosphate, silver stearate, silver thiocyanate, silver carbonate, silver saccharinate, silver anthranilate and combinations thereof.  
     
     
         28 . The packaged article of  claim 26  wherein the dried coated substrate further comprises silver metal in the zero-valent state and has a yellowish color.  
     
     
         29 . The packaged article of  claim 28  which is color stable after gamma or e-beam irradiation.  
     
     
         30 . The packaged article of  claim 28  which is color stable during and after gamma or e-beam irradiation.  
     
     
         31 . The packaged article of  claim 26  which has a whitish color and activated carbon sealed with the article within the packaging.  
     
     
         32 . The packaged article of  claim 26  wherein the substrate is a silver nitrate oxidizable substrate.  
     
     
         33 . The packaged article of  claim 26  wherein the substrate comprises a cellulosic material.  
     
     
         34 . The packaged article of  claim 33  wherein the substrate comprises cotton.  
     
     
         35 . The packaged article of  claim 26  wherein the substrate is a nonwoven gauze, a woven gauze, a porous film, a nonporous film, a knitted fabric, foam, or a hydrocolloid.  
     
     
         36 . The packaged article of  claim 26  wherein the substrate comprises a material selected from the group consisting of polyester, nylon, polyethylene, polypropylene, polyacrylonitrile, polyvinylidene difluoride, polytetrafluoroethylene, polyoxymethylene, polyvinyl chloride, polycarbonate, styrene-ethylenebutylene-styrene elastomer, styrene-butylene-styrene elastomer, styrene-isoprene-styrene elastomer, and combinations thereof.  
     
     
         37 . The packaged article of  claim 26  comprising stabilizing agents in an amount less than 100 ppm.  
     
     
         38 . The packaged article of  claim 26  wherein the antimicrobial article is maintained in an environment of no more than 50% RH at room temperature.  
     
     
         39 . The packaged article of  claim 38  wherein the antimicrobial article is maintained in an environment of no more than 30% RH at room temperature.  
     
     
         40 . The packaged article of  claim 39  wherein the article has a yellowish color, and further wherein the antimicrobial article is color stable during and after irradiation.  
     
     
         41 . The packaged article of  claim 26  wherein the silver sulfate composition further comprises silver compounds other than silver sulfate.  
     
     
         42 . The packaged article of  claim 26  wherein the packaging comprises material having an oxygen permeability of less than 0.01 cubic centimeter per 645 square centimeters per 24 hours.  
     
     
         43 . The packaged article of  claim 26  wherein the packaging comprises material having a moisture vapor transmission rate of less than 0.01 gram per 645 square centimeters per 24 hours.  
     
     
         44 . A method of whitening at least a portion of an antimicrobial article, the method comprising: 
 providing a packaged antimicrobial article having at least a portion colored other than white, wherein the article comprises a substrate coated with a silver salt composition comprising at least a portion of the silver in the zero-valent state, and wherein the antimicrobial article is sealed within packaging comprising material having a volatile organic content of greater than 100 mg per square meter; and    irradiating the packaged antimicrobial article to whiten at least a portion of the antimicrobial article.    
     
     
         45 . The method of  claim 44  wherein the silver salt composition comprises silver sulfate, silver nitrate, silver acetate, silver citrate, silver chloride, silver lactate, silver phosphate, silver stearate, silver thiocyanate, silver carbonate, silver saccharinate, silver anthranilate or combinations thereof.  
     
     
         46 . The method of  claim 45  wherein the silver salt composition comprises silver sulfate.  
     
     
         47 . The method of  claim 44  wherein irradiating comprises irradiating with gamma radiation and/or electron beam radiation.  
     
     
         48 . The method of  claim 44  wherein the substrate is a silver nitrate oxidizable substrate.  
     
     
         49 . The method of  claim 44  wherein the substrate comprises a cellulosic material.  
     
     
         50 . A packaged antimicrobial article made by the method of  claim 44.