Composite interlayer for laminates glass

Abstract

A composite interlayer suitable for using laminated glass includes a layer of plasticized polyvinyl butyral sandwiched between second and third polymeric layers. In a preferred embodiment, at least one and preferably both of the second and third layers are less than 5 mils thick and formed of polyurethane.

1 . A glass laminate comprising: 
 a first layer comprising a plasticized polyvinyl butyral and having a top surface and a bottom surface;    a first polyurethane layer adjacent said top surface of said first layer;    a second polyurethane layer adjacent said bottom surface of said first layer; 
 wherein at least one of said first and second polyurethane layers comprises polyurethane having a thickness of less than 5 mils for lamination to a rigid glass substrate;  
   a first glass layer adjacent said second polyurethane layer; and    a second glass layer adjacent said first polyurethane layer.    
     
     
         2 . The glass laminate of  claim 1  wherein both of said polyurethane layers comprise polyurethane having a thickness of less than 5 mils.  
     
     
         3 . The glass laminate of  claim 2  wherein said polyurethane is plasticized by migration of plasticizer from the first layer after the layers are combined.  
     
     
         4 . A multilayer composite suitable for use in glass laminates comprising: 
 a first layer comprising plasticized polyvinyl butyral and a second layer adjacent to said first layer comprising polyurethane, wherein plasticizer has migrated from said polyvinyl butyral to said polyurethane.    
     
     
         5 . The multilayer composite of  claim 4  wherein the polyurethane layer has a thickness of less than 5 mils.  
     
     
         6 . The multilayer composite of  claim 4  further comprising a third layer comprising polyurethane on a side of the polyvinyl butyral layer opposite the second layer.  
     
     
         7 . The multilayer composite of  claim 6  wherein the second and third polyurethane layers each have a thickness of less than 5 mils.