Two-part epoxy adhesives with improved flexibility and process for making and using same

Abstract

A two-part epoxy adhesive having a resin component containing a mixture of an epoxy resin and an internally flexibilized epoxy resin and a hardener component containing a mixture of a flexibilizer and an unmodified or modified aliphatic amine or combinations thereof. The resin component and hardener component are mixed and applied to substrates, or applied to substrates and mixed, an then allowed to cure yielding a cured epoxy resin having a tensile elongation at room temperature of greater than 30%. The initial curing time is less than 3 hours.

What is claimed is:  
     
         1 . A two-part epoxy adhesive comprising: 
 a) a resin component comprising a mixture of epoxy resin and an internally flexibilized epoxy resin, and    b) a hardener component comprising a mixture of a flexibilizer and an unmodified or modified aliphatic amine or combinations thereof, 
 wherein after said resin component and said hardener component are mixed and reacted the cured epoxy adhesive has a tensile elongation at room temperature of greater than 30%.  
   
     
     
         2 . The two-part epoxy adhesive of  claim 1  wherein the epoxy adhesive has an initial curing time of less than 3 hours.  
     
     
         3 . The two-part epoxy adhesive of  claim 1  wherein said resin-component further includes a plasticizer/accelerator, a coupling agent, fillers, and a thixotropic agent.  
     
     
         4 . The two-part epoxy adhesive of  claim 1  wherein said hardener component further includes an accelerator and a thixotropic agent.  
     
     
         5 . The two-part epoxy adhesive of  claim 1  wherein said resin component comprises by weight: 
 30-75% epoxy resin,  
 5-40% internally flexibilized epoxy resin,  
 5-40% plasticizer/accelerator,  
 0.1-1% coupling agent,  
 11-45% filler, and  
 1-8% thixotrophic agent.  
 
     
     
         6 . The two-part epoxy adhesive of  claim 5  wherein said epoxy resin is a Bisphenol A epoxy resin, said internally flexibilized epoxy resin is an internally flexibilized Bisphenol A type epoxy resin, said plasticizer/accelerator is a phenol based plasticizer/accelerator, said coupling agent is an epoxide functional silane base coupling agent and said filler is a mixture of limestone filler and white pigment.  
     
     
         7 . The two-part epoxy adhesive of  claim 6  wherein said hardener component comprises by weight: 
 20-80% flexibilizer  
 5-30% unmodified aliphatic amine,  
 1-10% accelerator  
 10-50% modified aliphatic amine, and  
 1-8% thixotropic agent.  
 
     
     
         8 . The two-part epoxy adhesive of  claim 7  wherein said flexibilizer is an amine terminated butadiene acrylonitrile adduct, said unmodified aliphatic amine is an unmodified glycol ether base aliphatic amine, said accelerator is a tertiary amine accelerator, and said modified aliphatic amine is an AEP base modified amine.  
     
     
         9 . A two-part epoxy adhesive comprising: 
 a) a resin component comprising a mixture of epoxy resin and an internally flexibilized epoxy resin, and    b) a hardener component comprising a mixture of flexibilizer and an unmodified or modified aliphatic amine or combinations thereof, 
 wherein the reactive mixture of said resin component and said hardener component has an initial curing time of about 1.5-2 hours and after curing the epoxy adhesive has a tensile elongation at room temperature of greater than 120%.  
   
     
     
         10 . The two-part epoxy adhesive of  claim 9  comprising: 
 a) a resin component comprising a mixture of: 
 40-45% Bisphenol A epoxy resin,  
 8-15% internally flexibilized Bisphenol A type epoxy resin,  
 10-20% phenol base plasticizer/accelerator,  
 0.3-0.6% epoxide functional silane base coupling agent,  
 15-25% limestone filler,  
 0.5-2% white pigment and  
 4-6% thixotrophic agent, and  
 
 b) a hardener component comprising a mixture of: 
 40-45% amine terminated butadiene acrylonitrile adduct,  
 7-15% unmodified glycol ether base aliphatic amine  
 5-8% tertiary amine accelerator,  
 25-40% AEP base modified amine, and  
 1-8% thixotrophic agent.  
 
 
     
     
         11 . The process of adhering at least two substrate surfaces to each other comprising the acts of: 
 intercalating between said surfaces an adhesive comprising a reactive mixture of: 
 a. a resin component comprising a mixture of epoxy resin and internally flexible epoxy resin, and  
 b. a hardener component comprising a mixture of a flexibilizer and an unmodified or modified aliphatic amine or combinations thereof,  
   and allowing said adhesive to cure, whereby said cured adhesive has a tensile elongation at room temperature of greater than 30%.    
     
     
         12 . The process of  claim 11  wherein in said act of curing it takes less than 3 hours for initial curing.  
     
     
         13 . The process of  claim 12  wherein said act of intercalating includes dispensing the resin component and hardener component in equal parts by volume and mixing until the mixture is relatively homogeneous and is applied relatively evenly to the substrates.  
     
     
         14 . The process of  claim 11  wherein said resin-component further includes a plasticizer/accelerator, a coupling agent, fillers, and a thixotropic agent.  
     
     
         15 . The process of  claim 11  wherein said hardener component further includes an accelerator and a thixotropic agent.  
     
     
         16 . The process of  claim 11  wherein said resin component comprises by weight: 
 30-75% epoxy resin,  
 5-40% internally flexibilized epoxy resin,  
 5-40% plasticizer/accelerator,  
 0.1-1% coupling agent,  
 11-45% filler, and  
 1-8% thixotrophic agent.  
 
     
     
         17 . The process of  claim 16  wherein said epoxy resin is a Bisphenol A epoxy resin, said internally flexibilized epoxy resin is an internally flexibilized Bisphenol A type epoxy resin, said plasticizer/accelerator is a phenol based plasticizer/accelerator, said coupling agent is an epoxide functional silane base coupling agent and said filler is a mixture of limestone filler and white pigment.  
     
     
         18 . The process of  claim 17  wherein said hardener component comprises by weight: 
 20-80% flexibilizer  
 5-30% unmodified aliphatic amine,  
 1-10% accelerator  
 10-50% modified aliphatic amine, and  
 1-8% thixotropic agent.  
 
     
     
         19 . The process of  claim 18  wherein said flexibilizer is an amine terminated butadiene acrylonitrile adduct, said unmodified aliphatic amine is an unmodified glycol ether base aliphatic amine, said accelerator is a tertiary amine accelerator, and said modified aliphatic amine is an AEP base modified amine.  
     
     
         20 . The process of  claim 11  wherein: 
 a) said resin component comprises a mixture of: 
 40-45% Bisphenol A epoxy resin,  
 8-15% internally flexibilized Bisphenol A type epoxy resin,  
 10-20% phenol base plasticizer/accelerator,  
 0.3-0.6% epoxide functional silane base coupling agent,  
 15-25% limestone filler,  
 0.5-2% white pigment and  
 4-6% thixotrophic agent, and  
 
 b) said hardener component comprises a mixture of: 
 40-45% amine terminated butadiene acrylonitrile adduct,  
 7-15% unmodified glycol ether base aliphatic amine,  
 5-8% tertiary amine accelerator,  
 25-40% AEP base modified amine, and  
 1-8% thixotrophic agent.  
 
 
     
     
         21 . A process for making a two-part epoxy adhesive comprising: 
 preparing a resin component by mixing an epoxy resin, an internally flexibilized epoxy resin, a plasticizer/accelerator, a coupling agent, fillers, and a thixotropic agent, and    preparing a hardener component comprising a mixture of a flexibilizer, an unmodified or modified aliphatic amine or combinations thereof, an accelerator a thixotropic agent.