Barrier coating comprising a polyurethane dispersion

Abstract

A barrier coating comprising a polyurethane dispersion is disclosed. The polyurethane comprises at least 30 weight percent of meta-substituted aromatic material. Methods for improving barrier using the coatings are also disclosed.

1 . A barrier coating comprising a polyurethane dispersion comprising at least 30 weight percent of meta-substituted aromatic material.  
     
     
         2 . The coating of  claim 1 , wherein the meta-substituted aromatic material comprises TDI, HER, MXDA, TMXDI and/or isophthalic acid.  
     
     
         3 . The coating composition of  claim 1 , wherein the polyurethane dispersion is water-based.  
     
     
         4 . The coating composition of  claim 1 , wherein the polyurethane dispersion is solvent-based.  
     
     
         5 . The coating composition of  claim 1 , wherein the polyurethane dispersion comprises a polyester polyol.  
     
     
         6 . The coating of  claim 1 , wherein the polyurethane has a Molar Permachor Number of at least 50.  
     
     
         7 . The coating of  claim 1 , further comprising a crosslinker.  
     
     
         8 . The coating of  claim 7 , wherein the crosslinker comprises aziridine.  
     
     
         9 . The coating of  claim 1 , wherein the polyurethane dispersion comprises a blend of two or more polyurethane dispersions.  
     
     
         10 . The coating of  claim 1 , further comprising one or more polymers.  
     
     
         11 . The coating of  claim 10 , wherein the one or more polymers imparts additional barrier to the coating.  
     
     
         12 . The coating of  claim 11 , wherein one of the polymers is polyvinylidene chloride and/or copolymers comprising polyvinylidene chloride.  
     
     
         13 . The coating of  claim 1 , further comprising a colorant.  
     
     
         14 . The coating of  claim 1 , further comprising a high aspect ratio pigment.  
     
     
         15 . The coating of  claim 13 , wherein the colorant is a polyester nylon composite.  
     
     
         16 . A barrier coating having a Molar Permachor Number of at least 50.  
     
     
         17 . A method for improving barrier on the substrate, comprising applying to the substrate the coating of  claim 1 .  
     
     
         18 . The method of  claim 17 , wherein the substrate is a flexible substrate.  
     
     
         19 . The method of  claim 17 , wherein the substrate is an elastic substrate.