This invention relates to a process to make a reaction product UA of at least one multifunctional aldehyde A with at least one cyclic urea U, by mixing the at least one multifunctional aldehyde A with the at least one cyclic urea U in the presence of at least one alcohol R1—OH, and optionally, at least one solvent that has no reactive groups which may react with aldehyde groups, —CO—NH— groups, or hydroxyl groups, to effect an addition reaction to obtain a solution of a product UA, where R1 is selected from the group consisting of linear, branched or cyclic alkyl groups having from one to twelve carbon atoms, to the reaction product obtained by this process, and to a method of use thereof as crosslinker for coating compositions.