Phenolic urethane foundry binder

Abstract

The present invention provides a novel phenolic urethane binder composition having a drying oil copolymer in the polyisocyanate resin component. The drying oil copolymers include linseed oil copolymers. The phenolic urethane binders of the present invention are useful in making foundry cores and molds. These foundry binders provide decreased gel formation and improved stability. Foundry mixes prepared using these phenolic urethane binders exhibit improved bench life properties.

1 . A phenolic urethane binder composition comprising: 
 a phenolic resin component;    a polyisocyanate resin component, the polyisocyanate resin component comprising a polyisocyanate and a drying oil copolymer; and    a catalyst in an amount effective to cure the resin components.    
   
   
       2 . The binder of  claim 1  wherein the drying oil copolymer is a copolymer of linseed oil and dicyclopentadiene.  
   
   
       3 . The binder of  claim 1  wherein the catalyst is a tertiary amine.  
   
   
       4 . A foundry mix comprising sand and the phenolic urethane binder of  claim 1 .  
   
   
       5 . The foundry mix of  claim 5  wherein the binder is present in an amount ranging from about 1% to about 10% based on the weight of the sand.  
   
   
       6 . The binder of  claim 2  wherein the catalyst is a tertiary amine.  
   
   
       7 . A foundry mix comprising sand and the phenolic urethane binder of  claim 2 .  
   
   
       8 . The foundry mix of  claim 7  wherein the binder is present in an amount ranging from about 0.4% to about 6% based on the weight of the sand.  
   
   
       9 . The binder of  claim 2  wherein the linseed oil-dicyclopentadiene copolymer is present in an amount ranging from about 0.25% to about 7.5% based on the total weight of the binder.  
   
   
       10 . The binder of  claim 2  wherein the linseed oil-dicyclopentadiene copolymer is present in an amount ranging from about 1% to about 6% based on the total weight of the binder.  
   
   
       11 . The binder of  claim 1  wherein the drying oil copolymer is a natural oil copolymer.  
   
   
       12 . A curable phenolic urethane binder, comprising: 
 a phenolic resin in an amount ranging from about 15% to about 40% based on the total weight of the binder;    a polyisocyanate in an amount ranging from about 15% to about 40% based on the total weight of the binder; and    a copolymer of linseed oil and dicyclopentadiene in an amount ranging from about 0.25% to about 7.5% based on the total weight of the binder.    
   
   
       13 . A foundry mix comprising sand and the curable phenolic urethane binder of  claim 12  in an amount ranging from about 0.4% to about 6% based on the weight of the sand.  
   
   
       14 . A resin component composition for use in a foundry binder, comprising: 
 a polyisocyanate; and    a drying oil copolymer.    
   
   
       15 . The resin component composition of  claim 14  wherein the drying oil copolymer is a copolymer of linseed oil and dicyclopentadiene.  
   
   
       16 . The resin component composition of  claim 14  wherein the drying oil copolymer is a natural oil copolymer.  
   
   
       17 . A foundry core or mold made using the binder composition of  claim 1 .  
   
   
       18 . A foundry core or mold made using the binder composition of  claim 2.