A process to make a reaction product UA of at least one multifunctional aldehyde A with at least one cyclic urea U, by a) mixing the at least one multifunctional aldehyde A with the at least one cyclic urea U in the presence of at least one alcohol R 1 -OH to a temperature of between 35°C and 50 °C to effect an addition reaction, optionally, in the presence of at least one solvent that has no reactive groups which may react with aldehyde groups, -CO-NH- groups, or hydroxyl groups, to obtain a solution of a product UA, where R 1 is 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, characterised in that the cyclic urea U is selected from the group consisting of ethylene urea, 1,3-propylene urea, 1,2-propylene urea, 1,4-butylene urea, and glycol uril, wherein the addition reaction is conducted in a pH range of more than 7.5 or in a pH range of from 4.5 to 7.5, and wherein after the addition reaction of step a), b) the pH is adjusted to at most 5.0 c) optionally, adding a further quantity of the said aliphatic alcohol R 1 -OH; and optionally, adding at least one solvent that has no reactive groups which react with aldehyde groups, -CO-NH- groups, or hydroxyl groups; and etherifying under acid conditions d) adding a further aliphatic alcohol R 2 -OH which has at least one carbon atom in its molecule more that there is in R 1 -OH; optionally, adding at least one solvent that has no reactive groups which react with aldehyde groups, -CO-NH- groups, or hydroxyl groups; and etherifying under acid conditions. a) mixing the at least one multifunctional aldehyde A with the at least one cyclic urea U in the presence of at least one alcohol R 1 -OH to a temperature of between 35°C and 50 °C to effect an addition reaction, optionally, in the presence of at least one solvent that has no reactive groups which may react with aldehyde groups, -CO-NH- groups, or hydroxyl groups, to obtain a solution of a product UA, where R 1 is 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, characterised in that the cyclic urea U is selected from the group consisting of ethylene urea, 1,3-propylene urea, 1,2-propylene urea, 1,4-butylene urea, and glycol uril, wherein the addition reaction is conducted in a pH range of more than 7.5 or in a pH range of from 4.5 to 7.5, and wherein after the addition reaction of step a), b) the pH is adjusted to at most 5.0 c) optionally, adding a further quantity of the said aliphatic alcohol R 1 -OH; and optionally, adding at least one solvent that has no reactive groups which react with aldehyde groups, -CO-NH- groups, or hydroxyl groups; and etherifying under acid conditions d) adding a further aliphatic alcohol R 2 -OH which has at least one carbon atom in its molecule more that there is in R 1 -OH; optionally, adding at least one solvent that has no reactive groups which react with aldehyde groups, -CO-NH- groups, or hydroxyl groups; and etherifying under acid conditions.