Radiation- or thermally-curable oxetane barrier sealants

Abstract

This invention relates to cationically curable sealants that provide low moisture permeability and good adhesive strength after cure. The composition consists essentially of an oxetane compound and a cationic initiator.

1 . A cationically curable barrier composition consisting essentially of 
 (a) an oxetane compound,    (b) a cationic initiator,    (c) optionally, one or more fillers,    (d) optionally one or more adhesion promoters, or one or more epoxy resins.    
     
     
         2 . The cationically curable barrier composition in accordance with  claim 1 , in which the oxetane compound has the structure:  
       
         
           
           
               
               
           
         
       
       in which R 1 , R 2 , R 3 , R 4 , R 5 , R 6  are selected from the group consisting hydrogen, and alkyl, haloalkyl, alkoxy, aryloxy, aryl, ester, thio-ester, and sulfide groups.  
     
     
         3 . The cationically curable barrier composition in accordance with  claim 1 , in which the oxetane compound is selected from the group of oxetane compounds having the structures:  
       
         
           
           
               
               
           
         
       
     
     
         4 . The cationically curable barrier composition in accordance with  claim 1 , in which the oxetane compound has an aromatic core, onto which aromatic core are substituted in a meta-position with each other, the oxetane functionality and an additional polymerizable functionality.  
     
     
         5 . The cationically curable barrier composition in accordance with  claim 1 , in which the oxetane compound has the structure:  
       
         
           
           
               
               
           
         
       
       in which 
 R 7 , R 8 , R 9 , R 10  and R 11  are independently selected from the group consisting of hydrogen, alkyl, haloalkyl, alkoxy, aryloxy, aryl, alkyloyl and aryloyl groups;  
 n is 0, 1, 2, 3, or 4;  
 Z is a cationically reactive functionality selected from the group consisting of  
                     
 in which  
 R 11  and R 12  are independently selected from the group consisting of hydrogen, alkyl, haloalkyl, alkoxy, aryloxy, aryl, alkyloyl and aryloyl groups; and  
 R 13  is a linking group selected from the group consisting of alkyl, haloalkyl, aryl, ether, thio-ether, ester, thio-ester, silane, carbonate, or ketone.  
 
     
     
         6 . The cationically curable barrier composition in accordance with  claim 5 , in which the oxetane compound is selected from the group having the structures:  
       
         
           
           
               
               
           
         
       
     
     
         7 . The cationically curable barrier composition in accordance with  claim 1 , in which the oxetane compound is a hybrid compound having both an oxetane and a second reactive functionality extending from a cycloaliphatic backbone.  
     
     
         8 . The cationically curable barrier composition in accordance with  claim 1 , in which the oxetane compound has the structure  
       
         
           
           
               
               
           
         
       
       in which 
 L, L′, L″ and L′″ are linking groups independently selected from the group consisting of  
                     
 R and R′ independently are selected from the group consisting of linear alkyl, branched alkyl, cycloalkyl, aryl, heteroaryl, silane or siloxane groups;  
 R″ is independently selected from the group consisting of hydrogen, alkyl, haloalkyl, alkoxy, aryloxy, aryl, alkyloyl and aryloyl groups;  
 X is a reactive group independently selected from the group consisting of glycidyl epoxy, aliphatic epoxy, and cycloaliphatic epoxy; oxetane; vinyl, propenyl, crotyl, allyl, and propargyl ether and thio-ethers of those groups; acrylate and methacrylate; itaconate; maleimide; maleate, fumarate, and cinnamate esters; styrenic; acrylamide and methacrylamide; chalcone; thiol; allyl, alkenyl, and cycloalkenyl groups;  
 n, k, l, n′, k′, and l′ are 0 or 1; and  
 y is 1 to 10.  
 
     
     
         9 . The cationically curable barrier composition in accordance with  claim 8 , in which the oxetane compound has the structure selected from the group consisting of:  
       
         
           
           
               
               
           
         
       
     
     
         10 . The cationically curable barrier composition in accordance with any of claims  1  through  9  in which the cationic initiator is a Brφnsted acid, a Lewis acid, or a photo or thermal acid generator.  
     
     
         11 . The cationically curable barrier composition in accordance with any of claims  1  through  9  in which one or more fillers are present.  
     
     
         12 . The cationically curable barrier composition in accordance with any of claims  1  through  9  in which one or more fillers are present and are selected from the group consisting of ground quartz, fused silica, amorphous silica, talc, glass beads, graphite, carbon black, alumina, clays, mica, vermiculite, aluminum nitride, boron nitride; silver, copper, gold, tin, tin/lead alloys, poly(tetrachloroethylene), poly(chlorotriflouroethylene), poly(vinylidene chloride), CaO, BaO, Na 2 SO 4 , CaSO 4 , MgSO 4 , zeolites, silica gel, P 2 O 5 , CaCl 2 , and Al 2 O 3    
     
     
         13 . The cationically curable barrier composition in accordance with any of claims  1  through  9  in which one or more epoxy resins are present.  
     
     
         14 . The cationically curable barrier composition in accordance with any of claims  1  through  9  in which one or more epoxy resins are present and are selected from the group consisting of bisphenol F diglycidyl ether, resorcinol diglycidyl ether, novolac glycidyl ethers, and halogenated glycidyl ethers.  
     
     
         15 . The cationically curable barrier composition in accordance with any of claims  1  through  9  in which one or more adhesion promoters are present.  
     
     
         16 . The cationically curable barrier composition in accordance with any of claims  1  through  9  in which an adhesion promoter is present and is a silane.  
     
     
         17 . A hybrid compound containing both oxetane and epoxy functionality selected from the group consisting of:  
       
         
           
           
               
               
           
         
       
     
     
         18 . An electronic or optoelectronic device sealed with the cationically-curable barrier sealant according to any one of  claims 1  to  9 .  
     
     
         19 . The electronic or optoelectronic device according to  claim 18  in which the device is an OLED.