Electrodeposition coating containing a urethane.

摘要

Electrocoating bath containing a urethane of the formula R1-NHCOO-R2 where R1 is alkyl or a group of the formula B1-NH-B2-[X-B3]n-, R2 is a group of the formulae -(C2H4O)y-R1 and -(C3H7O) y-R or of the formula R is C1-C18-alkyl, Y is from zero to 4, B1 is hydrogen, alkyl or a group of the formula -COOR2, B2 and B3 can be identical or different and each is C2-C14-alkylene, n is an integer from 0 to 5, preferably from 0 to 2, X is -O-, -S-, -NH- or @N-(C1-C4)-alkyl, R3 is hydrogen or alkyl, alkenyl, hydroxyalkyl, phenyl or alkylphenyl, R4 and R5 can be identical or different and each is hydrogen or C1-C4-alkyl, and A is a direct bond or one of the groups -O-, -CH2O- or -CH2OCO-. The presence of these urethanes in the electrocoating bath reduces the number of surface defects in galvanised surfaces.