The invention relates to a coating composition comprising a reaction product UA of at least one multifunctional aldehyde A with at least one cyclic urea U, and a crosslinkable resin having at least one kind of functional groups selected from the group consisting of hydroxyl functional groups, acid functional groups, amide functional groups, amino functional groups, imino functional groups, mercaptan functional groups, phosphine functional groups, and carbamate functional groups, characterized in that the degree of etherification, measured as the ratio