Use of molecules having associative groups as hardeners for thermosetting resins

Abstract

The present invention pertains to the field of thermosetting or thermoset polymers mainly used as materials, coatings, or adhesives. The invention more specifically relates to the use of specific molecules having associative groups including a nitrogen heterocycle as a hardener or co-hardener of thermosetting polymers.

1 . A curing agent for a thermosetting resin, comprising a molecule carrying an associative group of formula (I): 
       
         
           
           
               
               
           
         
         in which: 
         R denotes a unit comprising at least one reactive functional group, selected from alcohol, thiol or amine functional group, 
         R′ denotes a hydrogen atom, 
         A denotes an oxygen or sulfur atom. 
       
     
     
         2 . The curing agent as claimed in  claim 1 , characterized in that R is chosen from H 2 N—(CH 2 ) n —, HS—(CH 2 ) n — or HO—(CH 2 ) n —, where n represents an integer between 1 and 18. 
     
     
         3 . The curing agent as claimed in  claim 1 , characterized in that said molecule carrying an associative group is chosen from: 1-(2-aminoethyl)imidazoli-done, 1-(2-hydroxyethyl)imidazolidone, 1-(2-[(2-aminoethyl)amino]ethyl)imidazolidone, 1-(2-[(2-{2-aminoethyl)amino}ethyl)amino]ethyl)imidazolidone or N-(6-aminohexyl)-N′-(6-methyl-4-oxo-1,4-dihydropy-rimidin-2-yl)urea. 
     
     
         4 . The curing agent as claimed in  claim 1 , in combination with a cocuring agent, for improving the adhesion of said resin to a support. 
     
     
         5 . The curing agent as claimed in  claim 1  in combination with a cocuring compound chosen from alkyl- or arylamines and in particular ethylenediamine, diethylenetriamine, triethylenetetramine and tetraethylenepentamine, cyclic diamines, in particular 1-2-diaminocyclohexane, isophoronediamine or N,N′-diisopropylisophoronediamine, aromatic primary diamines, in particular 4,4′-methylenedianiline, 4,4′-methylenebis(ortho-chloroaniline) or xylenediamine isomers, such as diethyltoluenediamine, hydroxyethyldiethylenetriamine, polyetheramines, BADGE-aliphatic amine adducts with an excess of amine functional groups relative to the glycidyls, polyamidoamines, polyamides, amidoamines, polymercaptans, the Mannich bases obtained by reaction between (poly)amine, formaldehyde and (alkyl)phenols, ketimines, dicyanodiamide, polyol epoxy resins and polyurethane-curing polyols. 
     
     
         6 . The curing agent as claimed in  claim 1 , characterized in that the thermosetting resin is chosen from epoxy resins, polyurethane resins, polyester resins and unsaturated polyester resins. 
     
     
         7 . The curing agent as claimed in  claim 1 , in which at least two thermosetting resins are employed. 
     
     
         8 . The curing agent as claimed in  claim 7 , characterized in that the two resins are different. 
     
     
         9 . The curing agent as claimed in  claim 1 , characterized in that the molecules carrying associative groups are used in combination with a cocuring agent at a content of 0.1 to 50% by weight, with respect to the total weight of the combination. 
     
     
         10 . The curing agent as claimed in  claim 1 , characterized in that n is equal to 1 or 2, and in that the thermosetting resin is present in water or in an aqueous emulsion.