Composite extrusion for trim seal strip and method for forming same

Abstract

A composite extrusion for an automotive seal strip is formed of an extruded body, and a veneer extruded onto the body. The extruded body is composed of ethylene-propylene diene rubber compound. The veneer is composed of a polymer blend that includes the reaction product of an acrylate polymer and a glycidyl acrylate polymer. The reaction of the acrylate polymer and the glycidyl acrylate polymer improves adhesion and also provides a barrier to inhibit migration of vulcanizing agents from the ethylene-propylene diene rubber body into the veneer that would otherwise cause discoloration during use.

1 . A method for forming a composite extrusion for a trim seal strip comprising: 
 extruding a body composed of ethylene-propylene diene rubber compound and having a surface;    extruding a layer onto said surface and composed of a polymer blend comprising an acrylate polymer and a glycidyl acrylate polymer; and    curing said layer to form a veneer bonded to the body, wherein said curing includes reacting said acrylate polymer and said glycidal acrylate polymer.    
   
   
       2 . The method of  claim 1  wherein said surface comprises diene groups and wherein said curing includes reacting a portion of said glycidyl acrylate polymer and said diene groups.  
   
   
       3 . The method of  claim 1  wherein the coating contains a coloring agent.  
   
   
       4 . The method of  claim 1  wherein the acrylate polymer and the glycidyl acrylate polymer form a reaction product having an affinity for ethylene-propylene diene rubber compound and forming an interfaced barrier effective to inhibit migration of polar agents from said body into said veneer.  
   
   
       5 . The method of  claim 1  wherein the glycidyl acrylate polymer is an ethylene glycidyl acrylate polymer.  
   
   
       6 . The method of  claim 1  wherein the glycidyl acrylate polymer is ethylene methyl acrylate glycidyl methacrylate terpolymer.  
   
   
       7 . A method for forming a composite extrusion comprising: 
 extruding a body composed of a ethylene-propylene diene precursor that includes diene groups and a vulcanizing agent;    extruding onto said body a veneer composed predominantly of a polyolefin compound and comprising a acrylate-based polymer and an ethylene glycidyl acrylate polymer; and    curing said body and said veneer to vulcanize the ethylene-propylene diene precursor to form ethylene-propylene diene rubber compound, and concurrently to react said acrylate-based polymer and said ethylene glycidyl acrylate compound in said veneer.    
   
   
       8 . The method of  claim 7  wherein a portion of said ethylene glycidyl acrylate polymer reacts with diene groups at a surface of said body to enhance adhesion of the veneer to the body.  
   
   
       9 . The method of  claim 7  wherein the reaction between said acrylate-based polymer and said ethylene glycidyl acrylate polymer forms a reaction product that provides a compatabilized polar interfacial barrier adjacent said ethylene-propylene diene rubber compound effective to inhibit migration of residual vulcanizing agents into the veneer.  
   
   
       10 . The method of  claim 7  wherein the glycidyl acrylate polymer is ethylene methyl acrylate glycidyl methacrylate terpolymer.  
   
   
       11 . The method of  claim 7  wherein the veneer comprises a coloring agent.  
   
   
       12 . The method of  claim 7  wherein the veneer is composed predominantly of a thermoplastic polyolefin.  
   
   
       13 . The method of  claim 12  wherein the thermoplastic polyolefin is a polyolefin elastomer.  
   
   
       14 . A composite extrusion for a trim seal comprising: 
 a body composed of ethylene-propylene diene rubber compound; and    a veneer extruded onto the body and composed of a polymer blend that includes a reaction product of an acrylate polymer and a glycidyl acrylate polymer.    
   
   
       15 . The composite extrusion of  claim 14  wherein the veneer is composed predominantly of a polyolefin compound, and wherein the reaction product is a compatibilizer to enhance adhesion of the veneer to the base.  
   
   
       16 . The composite extrusion of  claim 14  wherein the veneer contains a coloring agent.  
   
   
       17 . The composite extrusion of  claim 14  wherein the glycidyl acrylate polymer is an ethylene glycidyl acrylate polymer.  
   
   
       18 . The composite extrusion of  claim 14  wherein the glycidyl acrylate polymer is ethylene methyl acrylate glycidyl methacrylate terpolymer.  
   
   
       19 . A composite extrusion adapted for an automotive trim seal, said composite extrusion comprising: 
 a body composed of ethylene-propylene diene rubber compound; and    a co-extruded veneer applied to the body and composed of a blend comprising predominantly polyolefinic compound and containing a reaction product of an acrylate polymer and an ethylene glycidyl acrylate polymer.    
   
   
       20 . The composite extrusion of  claim 19  wherein the composite extrusion comprises an interface between the body and the veneer, and wherein the interface comprises a reaction product of a diene group of said ethylene-propylene diene rubber compound and said glycidyl acrylate polymer.  
   
   
       21 . The composite extrusion of  claim 19  wherein the veneer contains a coloring agent.  
   
   
       22 . The composite extrusion of  claim 19  wherein the ethylene-propylene diene rubber compound contains a residual vulcanizing agent, and wherein said reaction product provides a barrier effective to inhibit migration of the residual vulcanizing agent into the veneer.  
   
   
       23 . The composite extrusion of  claim 19  wherein the ethylene glycidyl acrylate polymer is ethylene methyl acrylate glycidyl methacrylate terpolymer.  
   
   
       24 . The composite extrusion of  claim 19  wherein the polyoelfin compound is a polyolefin elastomer.