Room temperature ionic liquid curing agent

Abstract

Epoxy curing agents are disclosed having an epoxy curing agent comprising at least one room temperature ionic liquid salt, the room temperature ionic liquid salt being a reaction product of (a) at least one polyalkylene polyamine compound represented by formula (I): wherein x, y, and z are integers of 2 and 3, m and n and integers of 1-3; and (b) an organic acid having pKa (the negative of the logarithm of the acid dissociation constant) less than 6. The liquid salt is a stable liquid at a temperature greater than 15° C. Curable epoxy-based compositions including the curing agent and articles formed by the curable epoxy-based compositions are also disclosed.

1 . An epoxy curing agent comprising at least one room temperature ionic liquid salt, the room temperature ionic liquid salt being a reaction product of:
 (a) at least one polyalkylene polyamine compound represented by formula (I):   
       
         
           
           
               
               
           
         
         wherein x, y, and z are integers of 2 and 3, m and n are integers of 1-3; and 
         (b) an organic acid having pKa less than 6. 
       
     
     
         2 . The epoxy curing agent of  claim 1 , wherein the at least one polyalkylene polyamine compound is a mixture of dissimilar polyalkylene polyamine compounds. 
     
     
         3 . The epoxy curing agent of  claim 1 , wherein the at least one polyalkylene polyamine compound is a derivative of polyalkylene polyamine. 
     
     
         4 . The epoxy curing agent of  claim 1 , wherein the derivative of polyalkylene polyamine is one or more compounds selected from alkylated polyalkylene polyamine, benzylated polyalkylene polyamine, hydroxyalkylated polyalkylene polyamine, and polyalkylene polyamine adduct. 
     
     
         5 . The epoxy curing agent of  claim 1 , wherein the organic acid is selected from the group consisting of p-toluenesulfonic acid, trifluoromethanesulfonic acid, fluorosulfuric acid, salicylic acid, trifluoroacetic acid, 2-ethylhexanoic acid; tetrafluoroboric acid; thiocyanic acid; and combinations thereof. 
     
     
         6 . The epoxy curing agent of  claim 1 , wherein the molar ratio of component (b) to component (a) in a reaction mixture forming the reaction product is from greater than 0 to 1.8. 
     
     
         7 . The epoxy curing agent of  claim 1 , wherein the molar ratio of component (b) to component (a) in a reaction mixture forming the reaction is from 0.3 to 1.3. 
     
     
         8 . The epoxy curing agent of  claim 1 , further comprising a second amine, the second amine being a primary amine, a secondary amine, a tertiary amine, a quaternary amine, or derivative thereof. 
     
     
         9 . The epoxy curing agent of  claim 8 , wherein the second amine is a compound selected from the group consisting of aminoethylpiperazine, isophoronediamine, 4,4′-Methylenebis(cyclohexylamine), Ether amine, and combinations thereof. 
     
     
         10 . A curable epoxy-based composition comprising:
 (i) at least one epoxy resin; and   (ii) an epoxy curing agent comprising at least one room temperature ionic liquid salt, the room temperature ionic liquid salt being a reaction product of:   (a) at least one polyalkylene polyamine compound represented by formula (I):   
       
         
           
           
               
               
           
         
         
           wherein x, y, and z are integers of 2 and 3, m and n are integers of 1-3; and 
         
         (b) an organic acid having pKa less than 6. 
       
     
     
         11 . The curable epoxy-based composition of  claim 10 , wherein the at least one epoxy resin includes compounds selected from the group consisting of bisphenol-A diglycidyl ethers, bisphenol-F diglycidyl ethers, and epoxy novolacs. 
     
     
         12 . The curable epoxy-based composition of  claim 10 , further comprising (iii) a second amine, the second amine being a primary amine, a secondary amine, a tertiary amine, a quaternary amine, or derivative thereof. 
     
     
         13 . The curable epoxy-based composition of  claim 12 , wherein the (iii) second amine is a compound selected from the group consisting of aminoethylpiperazine, isophoronediamine, 4,4′-Methylenebis(cyclohexylamine), Ether amine, and combinations thereof. 
     
     
         14 . The curable epoxy-based composition of  claim 10 , further comprising (iv) at least one modifier selected from the group consisting of benzyl alcohol, furfuryl alcohol, polyethylene glycol and combinations thereof. 
     
     
         15 . The curable epoxy-based composition of  claim 14 , further comprising (v) an acrylate. 
     
     
         16 . The curable epoxy-based composition of  claim 15 , wherein the (v) acrylate is selected from the group consisting of lauryl acrylate, 1,6-hexanediol diacrylate, trimethylolpropanetriacrylate, poly(alkylene oxide) diacrylate, polyurethane diacrylate and combinations thereof. 
     
     
         17 . A method for forming a cured epoxy comprising mixing the curable epoxy-based composition according to  claim 10 . 
     
     
         18 . A cured epoxy resin comprising the contact product of the curable epoxy-based composition of  claim 10 . 
     
     
         19 . An article obtained from the composition of  claim 10 . 
     
     
         20 . The article of  claim 19 , wherein the article is an adhesive, a coating, a primer, a sealant, a curing compound, a construction product, a flooring product, or a composite product.