The reaction between the epoxy resin and the amine is preferably carried out by heating the reactants at 50??? to 150??? C. in an organic solvent, for example an alcohol such as methanol, ethanol, isopropanol or butanol, an ether alcohol such as 2-ethoxyethanol, 2-methoxyethanol or 2-butoxyethanol, an ester such as ethyl acetate or butyl acetate and/or an aromatic hydrocarbon such as xylene or tol