Microporous sheets with barrier coatings

Abstract

Microporous sheets coated with barrier coatings are disclosed.

1 . A coated microporous sheet comprising: 
 a microporous sheet; and    a barrier coating over at least a portion of the microporous sheet.    
     
     
         2 . The coated microporous sheet of  claim 1 , wherein the barrier coating has an oxygen permeability of less than 3 cm 3 -mil-/100 inches 2 /atmosphere/day.  
     
     
         3 . The coated microporous sheet of  claim 1 , wherein the barrier coating has an oxygen permeability of less than 1 cm 3 -mil/100 inches 2 /atmosphere/day  
     
     
         4 . The coated microporous sheet of  claim 1 , wherein the barrier coating comprises a polyurethane.  
     
     
         5 . The coated microporous sheet of  claim 4 , wherein the polyurethane comprises at least 60 weight percent of meta-substituted aromatic material.  
     
     
         6 . The coated microporous sheet of  claim 5 , wherein the polyurethane dispersion comprises a polyester polyol.  
     
     
         7 . The coated microporous sheet of  claim 5 , wherein the polyurethane has a Molar Permachor Number of at least 50.  
     
     
         8 . The coated microporous sheet of  claim 1 , wherein the coating further comprises one or more polymers.  
     
     
         9 . The coated microporous sheet of  claim 8 , wherein one or more polymers imparts additional barrier to the coating.  
     
     
         10 . The coating microporous sheet of  claim 9 , wherein one of the polymers is polyvinylidene chloride and/or copolymers comprising polyvinylidene chloride.  
     
     
         11 . The coated microporous sheet of  claim 1 , wherein the barrier coating further comprises high aspect ratio platelets.  
     
     
         12 . The coated microporous sheet of  claim 1 , further comprising an intermediate layer between the barrier coating and the microporous sheet.  
     
     
         13 . The coated microporous sheet of  claim 1 , wherein the microporous sheet comprises a polymer matrix.  
     
     
         14 . The coated microporous sheet of  claim 1 , wherein the microporous sheet comprises a polyethylene matrix and from about 30 to about 95 volume percent pores.  
     
     
         15 . The coated microporous sheet of  claim 1 , wherein the microporous sheet is flexible.  
     
     
         16 . The coated microporous sheet of  claim 1 , wherein the microporous sheet is elastic.  
     
     
         17 . A method of coating a microporous sheet, comprising applying a gas barrier coating composition on the microporous sheet.  
     
     
         18 . The method of  claim 17 , wherein the gas barrier coating composition comprises a polyurethane.  
     
     
         19 . The method of  claim 18 , wherein the polyurethane comprises at least 30 weight percent of meta-substituted aromatic material.  
     
     
         20 . The coated microporous sheet of  claim 1 , wherein the barrier coating is over substantially all of the sheet.