Urea-aldehyde polycondensates, preparation thereof and use thereof as surface coating binders

摘要

Urea-aldehyde polycondensates usable as surface coating binders are obtainable by step-wise reaction of (a) urea and/or urea derivatives with acidic CH aldehydes in a molar ratio of urea:aldehyde of 1:2 in the presence of acids and at from 60 DEG to 120 DEG C. with (b) a mixture of 3 moles of formaldehyde per mole or urea and 3 moles of an acidic CH aldehyde per mole of urea at from 60 DEG to 120 DEG C. with subsequent removal of the water of reaction and treatment of the reaction mixture with an alkali metal alcoholate at from 80 DEG to 100 DEG C.