Amine for low-emission epoxy resin compositions

Abstract

The use of an amine of formula (I) as a component of a hardener for epoxy resins, hardeners for epoxy resins containing the amine of formula (I), and resultant epoxy resin compositions which can particularly be used as low-emission room-temperature-curing epoxy-resin coatings with high hardness and surface quality. The amine of formula (I) is low-odour and a very successful diluent for epoxy resin compositions. It is particularly obtained by reductive alkylation from 1,2-ethylenediamine or 1,2-propylenediamine and an aldehyde or ketone.

1 . An epoxy resin composition comprising
 a resin component comprising at least one epoxy resin and   a hardener component comprising at least one amine of the formula (I),   
       
         
           
           
               
               
           
         
         where 
         X is 1,2-ethylene or 1,2-propylene, 
         R is a hydrogen radical or is a hydrocarbon radical having 1 to 6 carbon atoms, 
         A is a five-, six- or seven-membered cycloalkyl radical having 4 to 7 carbon atoms and in the ring contains an oxygen, sulfur or nitrogen atom, 
         Y is identical or different radicals selected from the group consisting of alkyl, alkoxy and dialkylamino having 1 to 18 carbon atoms, and 
         n is 0 or 1 or 2 or 3. 
       
     
     
         2 . The epoxy resin composition as claimed in  claim 1 , wherein X is 1,2-ethylene. 
     
     
         3 . The epoxy resin composition as claimed in  claim 1 , wherein R is a hydrogen radical. 
     
     
         4 . The epoxy resin composition as claimed in  claim 1 , wherein A is a five- or six-membered cycloalkyl radical having 4 to 6 carbon atoms and the ring contains an oxygen atom. 
     
     
         5 . The epoxy resin composition as claimed in  claim 1 , wherein R is a hydrogen radical and n is 0. 
     
     
         6 . The epoxy resin composition as claimed in  claim 1 , wherein A is a five-membered cycloalkyl radical having 4 carbon atoms and one oxygen atom. 
     
     
         7 . The epoxy resin composition as claimed in  claim 1 , wherein A is a tetrahydrofuran-2-yl or a tetrahydrofuran-3-yl radical. 
     
     
         8 . The epoxy resin composition as claimed in  claim 1 , wherein the amine of the formula (I) is obtained from the reductive alkylation of 1,2-ethylenediamine or 1,2-propylenediamine with at least one aldehyde or ketone of the formula (II) and hydrogen, 
       
         
           
           
               
               
           
         
         where G is A or an unsaturated radical which can be hydrogenated to A. 
       
     
     
         9 . The epoxy resin composition as claimed in  claim 8 , wherein 1,2-ethylenediamine or 1,2-propylenediamine is used in a stoichiometric excess over the carbonyl groups and the excess is removed distillatively after the reduction. 
     
     
         10 . A hardener for epoxy resins, comprising at least one amine of the formula (I), 
       
         
           
           
               
               
           
         
         where 
         X is 1,2-ethylene or 1,2-propylene, 
         R is a hydrogen radical or is a hydrocarbon radical having 1 to 6 carbon atoms, 
         A is a five-, six- or seven-membered cycloalkyl radical having 4 to 7 carbon atoms and in the ring contains an oxygen, sulfur or nitrogen atom, 
         Y is identical or different radicals selected from the group consisting of alkyl, alkoxy and dialkylamino having 1 to 18 carbon atoms, and 
         n is 0 or 1 or 2 or 3, and 
       
       at least one further amine not corresponding to the formula (I), and/or 
       at least one accelerator. 
     
     
         11 . The hardener as claimed in  claim 10 , wherein the further amine is selected from the group consisting of 2,2(4),4-trimethylhexamethylenediamine, 1,2-diaminocyclohexane, bis(4-aminocyclohexyl)methane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, 2(4)-methyl-1,3-diaminocyclohexane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(amino-methyl)cyclohexane, 2,5(2,6)-bis(aminomethyl)bicyclo[2.2.1]heptane, 1,3-bis(aminomethyl)benzene, 1,4-bis(aminomethyl)benzene, polyoxyalky-lenediamines, polyoxyalkylenetriamines, bis(hexamethylene)triamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, N,N′-bis(3-aminopropyl)ethylenediamine, N-benzyl-1,3-bis(aminomethyl)-benzene, N,N′-dibenzyl-1,3-bis(aminomethyl)benzene, N-2-ethylhexyl-1,3-bis(aminomethyl)benzene, N,N′-bis(2-ethylhexyl)-1,3-bis(aminome-thyl)benzene, N-benzyl-1,2-propanediamine, N-benzyl-1,2-ethanediamine and adducts of polyamines with epoxides. 
     
     
         12 . The hardener as claimed in  claim 10 , wherein the further amine is an adduct, containing at least three amine hydrogens, of at least one polyamine having 2 to 12 carbon atoms and at least one epoxide. 
     
     
         13 . The hardener as claimed in  claim 10 , wherein the hardener contains 5 to 65 weight % of the amine of the formula (I) based on the reactive constituents of the hardener. 
     
     
         14 . A cured composition obtained from the curing of the epoxy resin composition as claimed in  claim 1 . 
     
     
         15 . The epoxy resin composition as claimed in  claim 1 , which contains not more than 5 weight % of a diluent.