| abstract |
Soft and hard resins made from urea, formaldehyde and CH-acidic aldehyde are produced by using ureas of the general formula (I) or (II) in which R 1 and R 2 are hydrogen or identical or different alkyl radicals, A is an alkylene radical and X is oxygen or sulfur, with formaldehyde and a CH-acidic aldehyde of the general formula (III) wherein the radicals R 3 and R 4 are identical or different alkyl, aryl or alkylaryl radicals, in the temperature range between 60 and 150 ° C in the presence of acids, optionally in the presence of solvent and / or diluent, and then treated in an anhydrous medium with a base .n n n These soft and hard resins are used in combination with other film images as paint binders. |