Toughened Cyanoacrylate Compositions

Abstract

This invention relates to cyanoacrylate-containing compositions that include, in addition to the cyanoacrylate component, a rubber toughening component, which is substantially clear and colorless and which is substantially free of release agents and anti-oxidants known to impair the fixture speeds and shelf life stability of cyanoacrylate compositions to which they are added. As a result, the inventive rubber cyanoacrylate adhesive compositions demonstrate improved properties, such as fixture speed, strength and shelf life under accelerated aging conditions.

1 . A rubber toughened cyanoacrylate adhesive composition, comprising:
 (a) a cyanoacrylate component, and   (b) a rubber toughening agent consisting essentially of (a) reaction products of the combination of ethylene, methyl acrylate and monomers having carboxylic acid cure sites, (b) dipolymers of ethylene and methyl acrylate, and combinations of (a) and (b), and being substantially free of release agents, anti-oxidants, stearic acid and/or polyethylene glycol ether wax.   
   
   
       2 . The composition according to  claim 1 , further comprising a filler. 
   
   
       3 . The composition according to  claim 2 , wherein the filler is selected from the group consisting of carbon black, silica and combinations thereof. 
   
   
       4 . The composition of  claim 1 , further comprising a stabilizing amount of an acidic stabilizer a free radical inhibitor. 
   
   
       5 . The composition of  claim 1 , wherein the concentration of the rubber toughening agent is from about 1.5% to about 20% by weight. 
   
   
       6 . The composition according to  claim 1 , wherein the cyanoacrylate component is selected from materials within the structure H 2 C═C(CN)—COOR, wherein R is selected from C 1-15  alkyl, alkoxyalkyl, cycloalkyl, alkenyl, aralkyl, aryl, allyl and haloalkyl groups. 
   
   
       7 . The composition according to  claim 1 , wherein the cyanoacrylate component comprises ethyl-2-cyanoacrylate. 
   
   
       8 . The composition according to  claim 1 , further comprising an accelerator component selected from the group consisting of calixarene, oxacalixarene, silacrown, cyclodextrin, crown ether, poly(ethyleneglycol) di(meth)acrylate, ethoxylated hydric compound, and combinations thereof. 
   
   
       9 . The composition according to  claim 8 , wherein the calixarene is tetrabutyl tetra[2-ethoxy-2-oxoethoxy]calix-4-arene. 
   
   
       10 . The composition according to  claim 8 , wherein the crown ether is selected from members within the group consisting of 15-crown-5, 18-crown-6, dibenzo-18-crown-6, benzo-15-crown-5-dibenzo-24-crown-8, dibenzo-30-crown-10, tribenzo-18-crown-6, asym-dibenzo-22-crown-6, dibenzo-14-crown-4, dicyclohexyl-18-crown-6, dicyclohexyl-24-crown-8, cyclohexyl-12-crown-4, 1,2-decalyl-15-crown-5, 1,2-naphtho-15-crown-5, 3,4,5-naphtyl-16-crown-5, 1,2-methyl-benzo-18-crown-6, 1,2-methylbenzo-5,6-methylbenzo-18-crown-6, 1,2-t-butyl-18-crown-6, 1,2-vinylbenzo-15-crown-5, 1,2-vinylbenzo-18-crown-6, 1,2-t-butyl-cyclohexyl-18-crown-6, asym-dibenzo-22-crown-6, and 1,2-benzo-1,4-benzo-5-oxygen-20-crown-7 and combinations thereof. 
   
   
       11 . The composition according to  claim 8 , wherein the poly(ethyleneglycol) di(meth)acrylate is within the following structure: 
     
       
         
         
             
             
         
       
     
     wherein n is greater than 3. 
   
   
       12 . The composition according to  claim 1 , further comprising additives selected from the group consisting of shock resistant additives, thixotropy conferring agents, thickeners, dyes, thermal degradation resistance enhancers, and combinations thereof. 
   
   
       13 . The composition according to  claim 12 , wherein the shock resistant additive is citric acid. 
   
   
       14 . Reaction products of the composition according to  claim 1 . 
   
   
       15 . A method of bonding together two substrates, comprising the steps of:
 applying a cyanoacrylate-containing adhesive composition according to  claim 1 , to at least one of the substrates and   mating together the substrates for a time sufficient to permit the adhesive to fixture.   
   
   
       16 . A method of preparing a cyanoacrylate-containing composition according to  claim 1 , comprising the steps of:
 providing a cyanoacrylate component, and   combining therewith mixing a rubber toughening agent consisting essentially of (a) reaction products of the combination of ethylene, methyl acrylate and monomers having carboxylic acid cure sites, (b) dipolymers of ethylene and methyl acrylate, and combinations of (a) and (b), and being substantially free of release agents, anti-oxidants, stearic acid and/or polyethylene glycol ether wax.   
   
   
       17 . The composition according to  claim 1 , further comprising a metallocene and a photoinitiator. 
   
   
       18 . The composition according to  claim 1 , further comprising at least two of citric acid, phthalic anhydride and crown ether. 
   
   
       19 . The composition according to  claim 1 , further comprising a thermal degradation resistance enhancer selected from the group consisting of maleimide compounds mono, poly or hetero aromatic compounds characterized by at least three substitutions on an aromatic ring thereof, two or more of which being electron withdrawing groups, quinoid compounds, sulfur-containing compounds, cyclic sultanate naphthosulfone compounds substituted with at least one strong electron withdrawing group at least as strongly electron withdrawing as nitro, alkylating agents, silylating agents, and combinations thereof. 
   
   
       20 . The composition according to  claim 19 , wherein the thermal degradation resistance enhancer is selected from the group consisting of N,N′-meta-phenylene bismaleimide, an anhydrosulfite, a sulfoxide, a sulfite, a sulfonate, a methanesulfonate, a p-toluenesulfonate, polyvinyl benzyl chloride, 4-nitrobenzyl chloride, and combinations thereof.