Hardener composition for epoxy resins

Abstract

A hardener composition useful for curing epoxy resins including a blend of (a) a carboxylic anhydride which is a copolymer of an ethylenically unsaturated anhydride and a vinyl compound; (b) a copolymer of an ethylenically unsaturated anhydride and an elastomer; and optionally (c) a stabilizing agent such as a block copolymer to prevent phase separation of components (a) and (b). The hardener composition is particularly useful in electrical laminates applications.

1 . A hardener composition useful for curing a polyepoxide resin comprising a blend of 
 (a) a carboxylic anhydride which is a copolymer of an ethylenically unsaturated anhydride and a vinyl compound;    (b) a copolymer of an ethylenically unsaturated anhydride and an elastomer; and    (c) a stabilizing agent to prevent phase separation of components (a) and (b).    
     
     
         2 . The hardener composition of  claim 1  wherein the copolymer of an ethylenically unsaturated anhydride and a vinyl compound is a copolymer of styrene and maleic anhydride (SMA).  
     
     
         3 . The hardener composition of  claim 1  wherein the copolymer of an ethylenically unsaturated anhydride and an elastomer is a maleic anhydride-modified polybutadiene (PBMA).  
     
     
         4 . The hardener composition of  claim 1  wherein the stabilizing agent is a block copolymer  
     
     
         5 . The hardener composition of  claim 1  wherein the stabilizing agent is a triblock copolymer of styrene-butadiene-methyl methacrylate (SBM).  
     
     
         6 . The hardener composition of  claim 1  including 
 (d) a solvent.    
     
     
         7 . The hardener composition of  claim 1  including 
 (e) a cure inhibitor.    
     
     
         8 . The hardener composition of  claim 7  wherein the cure inhibitor is boric acid.  
     
     
         9 . The hardener composition of  claim 1  wherein the amount of the carboxylic anhydride which is a copolymer of an ethylenically unsaturated anhydride and a vinyl compound present in the composition is such that the epoxy to anhydride molar ratio is between about 0.8:1.0 and about 1.2:1.0.  
     
     
         10 . The hardener composition of  claim 1  wherein the amount of component (b) present in the composition is such that the component (a) to component (b) weight ratio is between about 95:5 and about 80:20.  
     
     
         11 . The hardener composition of  claim 1  wherein the amount of stabilizing agent present in the composition is such that the component (b) to component (c) weight ratio is between about 60:40 and about 95:5.  
     
     
         12 . A process for preparing a hardener composition comprising mixing 
 (a) a carboxylic anhydride which is a copolymer of an ethylenically unsaturated anhydride and a vinyl compound;    (b) a copolymer of an ethylenically unsaturated anhydride of an elastomer; and    (c) a stabilizing agent to prevent phase separation of components (a) and (b).