A curing agent for epoxy resins, a process for curing the epoxy resins using the curing agent and curable or cross-linkable compositions comprising the curing agent and the epoxy resins are described. The curing agent comprises the reaction product of 4,4''-diaminodiphenylmethane and the glycidyl ester of ''''Versatic'''' acid (a mixture of saturated, highly branched, mainly tertiary monocarboxylic acids having C9, C10, C11, chain lengths). The curing agent and epoxy resin are intimately mixed together and allowed to cure at a temperature ranging from room temperature to a temperature up to 150*C. The reaction product or adduct used as the curing agent permits the use of a particularly successful curing agent, 4,4''-diaminodiphenylmethane which is normally too viscous and too slow to cure to be mixed with epoxy resins.