Electric-arc resistant face shield or lens including ir-blocking inorganic nanoparticles

Abstract

A transparent electric-arc resistant composition is produced by preparing crystalline tungsten bronze nanoparticles and homogenously dispersing the nanoparticles in a transparent plastic matrix. The crystalline tungsten bronze nanoparticles are prepared by homogeneously mixing an aqueous solution of soluble tungsten and cesium salts and then drying the solution. The dried solution is then heated in a reducing gas or inert gas atmosphere to form crystalline tungsten bronze nanoparticles. Thereafter, a dispersion agent is added and the nanoparticles are dispersed in a liquid solvent medium by wet milling to form a dispersion mixture. The dispersion mixture is then mixed with polymer pellets to form a polymer mixture, and the polymer mixture is then extruded to yield polymer pellets containing highly homogeneously dispersed inorganic nanoparticles. During or after dispersion, additional particles, dyes, heat stabilizers or UV absorbers, may be added. A lens or shield is then molded from the polymer pellets.

What is claimed is: 
     
         1 . A transparent plastic composition resistant to an electric arc comprising:
 a transparent polymer material; and   inorganic nanoparticles dispersed within the polymer material so that the composition is substantially transparent.   
     
     
         2 . The composition of  claim 1 , wherein the polymer material is selected from the group consisting of a cellulosic polymer, polyester, polycarbonate, polysulfone and polyimide. 
     
     
         3 . The composition of  claim 1 , wherein the nanoparticles comprise tungsten. 
     
     
         4 . The composition of  claim 3 , wherein the nanoparticles are crystalline tungsten bronze. 
     
     
         5 . The composition of  claim 4 , wherein the nanoparticles are Cs 0.33 WO 3 . 
     
     
         6 . The composition of  claim 4 , wherein the nanoparticles are up to 0.2% of the composition, by weight. 
     
     
         7 . The composition of  claim 2 , wherein the nanoparticles comprise tungsten. 
     
     
         8 . The composition of  claim 7 , wherein the nanoparticles are crystalline tungsten bronze. 
     
     
         9 . The composition of  claim 8 , wherein the nanoparticles are Cs 0.33 WO 3 . 
     
     
         10 . The composition of  claim 8 , wherein the nanoparticles are up to 0.2% of the composition, by weight. 
     
     
         11 . An electric arc resistant lens for safety eyewear comprising:
 a transparent polymer material; and   inorganic nanoparticles dispersed within the polymer material so that the composition is substantially transparent.   
     
     
         12 . The lens of  claim 11 , wherein the polymer material is selected from the group consisting of a cellulosic polymer, polyester, polycarbonate, polysulfone and polyimide. 
     
     
         13 . The lens of  claim 11 , wherein the nanoparticles comprise tungsten. 
     
     
         14 . The lens of  claim 13 , wherein the nanoparticles are crystalline tungsten bronze. 
     
     
         15 . The lens of  claim 14 , wherein the nanoparticles are Cs 0.33 WO 3 . 
     
     
         16 . The lens of  claim 14 , wherein the nanoparticles are up to 0.2% of the composition, by weight. 
     
     
         17 . The lens of  claim 12 , wherein the nanoparticles comprise tungsten. 
     
     
         18 . The lens of  claim 17 , wherein the nanoparticles are crystalline tungsten bronze. 
     
     
         19 . The lens of  claim 18 , wherein the nanoparticles are Cs 0.33 WO 3 . 
     
     
         20 . The lens of  claim 18 , wherein the nanoparticles are up to 0.2% of the composition, by weight.