The invention relates to self-crosslinking aqueous polyurethane
dispersions containing a crosslinking agent I selected from diamones I1
and dihydrazides I2, and polyurethanes comprising structural elements
derived from polyisocyanates A, polyols B having a number average molar
mass M.sub.n of at least 400 g/mol, compounds D comprising at least two
groups which are reactive compared to isocyanate groups and at least one
group able to form anions, low-molecular polyols E that carry no other
reactive groups compared to isocyanate groups, compounds F containing at
least one group which is reactive compared to isocyanate, and at least
one aldehyde-type or ketone-type carbonyl group, and compounds G that are
monofunctional compared to isocyanates or contain active hydrogen with
different capabilities of reaction and are different from the compounds
E. The invention also relates to methods for the production of said
dispersions, and coating agents containing the same.