Reaction product of a cyclic urea and a multifunctional aldehyde

A reaction product UA of at least one cyclic urea U and at least one multifunctional aldehyde A which reaction product has as substituents on the carbonyl carbon atoms of the aldehyde A at least one kind of functional groups selected from the group consisting of hydroxyl groups —OH and alkoxy groups —OR characterized in that the groups —OR comprise alkoxy groups —OR1 and —OR2, where R1 and R2 are both selected from the group consisting of linear, branched or cyclic alkyl groups having from one to twelve carbon atoms, which may be interrupted by one or more of —O—, —NR″—, —S—, where R″ stands for H, or an alkyl group having from one to six carbon atoms, with the proviso that not two —O—or not two —S—atoms may be immediately adjacent, wherein

• R1 and R2 are different from each other, and R2 has at least one carbon atom more than R1, the reaction product UA being made by a process comprising the steps of
• a) mixing a multifunctional aldehyde A with a cyclic urea U to effect an addition reaction, optionally, in the presence of a co-solvent which does not react with any of the multifunctional aldehyde A, the cyclic urea U, and the reaction product UA,
• b) adding an aliphatic alcohol R1 —OH, and etherifying under acid conditions
• c) further etherifying under acid conditions with an added aliphatic alcohol R2 —OH which has at least one carbon atom in its molecule more that there is in R1 —OH,
• wherein the etherification is conducted in a sequential manner involving at least 2 subsequent steps b) and c), and
• wherein the reaction product UA has a degree of etherification, measured as the ratio n(RO—) / n(U) of the amount of substance n(RO—) of alkoxy groups to the amount of substance n(U) of cyclic urea U chemically bound in the reaction products, of at least 1.1 mol/mol.