Removable antifogging coatings, articles, coating compositions, and methods

Abstract

A coating composition which imparts antifog properties to substrates coated therewith. The coating compositions are removable and utilize nanoparticles funtionalized with epoxy groups. The removable coating compositions are particularly useful on personal protection equipment such as face masks, shields, and protective glasses.

1 . A method of providing antifogging characteristics to a substrate, the method comprising applying a coating composition to a substrate and allowing it to dry, wherein the coating composition is prepared at a pH of no greater than 6, and comprises:
 nanoparticles having a particle size of no greater than 60 nm, and comprising a silica surface having functional groups attached to the surface through covalent bonds, wherein the functional groups comprise:
 epoxy groups; and 
 optional water-dispersible groups; 
   an optional surfactant; and   water;   wherein the coating composition provides antifogging characteristics to a substrate on which it is coated and dried, and is removable after drying.   
     
     
         2 . The method of  claim 1  wherein the water-dispersible groups are present and comprise carboxylic acid groups, sulfonic acid groups, phosphonic acid groups, salts thereof, or combinations thereof. 
     
     
         3 . (canceled) 
     
     
         4 . The method of  claim 1  wherein the nanoparticles have a particle size of 4-5 nm. 
     
     
         5 . (canceled) 
     
     
         6 . (canceled) 
     
     
         7 . The method of  claim 1  wherein the coating composition is prepared at a pH of 1 to 3. 
     
     
         8 . (canceled) 
     
     
         9 . (canceled) 
     
     
         10 . (canceled) 
     
     
         11 . (canceled) 
     
     
         12 . (canceled) 
     
     
         13 . An antifogging coating composition comprising:
 nanoparticles having a particle size of no greater than 60 nm, and comprising a silica surface having functional groups attached to the surface through covalent bonds, wherein the functional groups comprise:
 epoxy groups; and 
 optional water-dispersible groups; 
   an optional surfactant; and   water;   wherein the coating composition is prepared at a pH of no greater than 6; and   wherein the coating composition provides antifogging characteristics to a substrate on which it is coated and dried, and is removable after drying.   
     
     
         14 . The composition of  claim 13  wherein the water-dispersible groups are present and comprise carboxylic acid groups, sulfonic acid groups, phosphonic acid groups, salts thereof, or combinations thereof. 
     
     
         15 . The composition of  claim 13  wherein the nanoparticles have a particle size of no greater than 20 nm. 
     
     
         16 . The composition of  claim 15  wherein the nanoparticles have a particle size of 4-5 nm. 
     
     
         17 . (canceled) 
     
     
         18 . (canceled) 
     
     
         19 . (canceled) 
     
     
         20 . The composition of  claim 13  wherein the coating composition comprises at least 0.2 wt-% nanoparticles, based on the total weight of the coating composition. 
     
     
         21 . (canceled) 
     
     
         22 . (canceled) 
     
     
         23 . The composition of  claim 13  wherein the coating composition further comprises an antimicrobial agent. 
     
     
         24 . The composition of  claim 13  impregnated into an applicator substrate. 
     
     
         25 . The composition of  claim 24  wherein the applicator substrate comprises a paper wipe. 
     
     
         26 . (canceled) 
     
     
         27 . A personal protection article comprising a substrate having a surface coated with an antifogging coating, wherein the coating comprises:
 nanoparticles having a particle size of no greater than 60 nm, and comprising a silica surface having functional groups attached to the surface through covalent bonds, wherein the functional groups comprise:
 epoxy groups; and 
 optional water-dispersible groups; and 
   an optional surfactant;   wherein the coating provides antifogging characteristics to the substrate and is removable; and   wherein the coating is formed upon drying a coating composition prepared at a pH of no greater than 6.   
     
     
         28 . The article of  claim 27  wherein the coating composition used to prepare the coating is prepared at a pH of 1 to 3. 
     
     
         29 . (canceled) 
     
     
         30 . The article of  claim 27  wherein the nanoparticles have a particle size of no greater than 20 nm. 
     
     
         31 . The article of  claim 30  wherein the nanoparticles have a particle size of 4-5 nm. 
     
     
         32 . (canceled) 
     
     
         33 . (canceled) 
     
     
         34 . (canceled) 
     
     
         35 . The article of  claim 27  wherein the coating composition used to prepare the coating comprises at least 0.1 wt-% surfactant, based on the total weight of the coating composition. 
     
     
         36 . The article of  claim 27  wherein the coating further comprises an antimicrobial agent. 
     
     
         37 . (canceled) 
     
     
         38 . A face shield comprising a substrate having a silicone surface and an antifogging coating on the silicone surface, wherein the antifogging coating comprises:
 nanoparticles having a particle size of 4-5 nm, and comprising a silica surface having functional groups attached to the surface through covalent bonds, wherein the functional groups comprise:
 epoxy groups; and 
 optional water-dispersible groups; and 
   an organosilicone surfactant; and   water;   wherein the coating provides antifogging characteristics to the substrate and is removable; and   wherein the coating is formed upon drying a coating composition prepared at a pH of 1 to 3.   
     
     
         39 . An antifogging applicator comprising an antifogging coating composition impregnated into an applicator substrate, wherein the coating composition comprises:
 nanoparticles having a particle size of 4-5 nm, and comprising a silica surface having functional groups attached to the surface through covalent bonds, wherein the functional groups comprise:
 epoxy groups; and 
 optional water-dispersible groups; 
   an organosilicone surfactant; and   water;   wherein the coating composition is prepared at a pH of 1 to 3; and   wherein the coating composition provides antifogging characteristics to a substrate on which it is coated and dried, and is removable after drying.