Aq. dispersions (I) contain (A) a radically polymerised polymer contg. 5-50 wt.% ethylenically unsatd. acid monomer units (A1) and (B) an anionically polymerised polymer. Also claimed is a process for the prodn. of (I), by producing polymer (A) or (B) in organic solvent in the presence of (B) or (A), or producing (A) and (B) in soln. separately and mixing the solns. or dispersions obtd., then dispersing the mixt. in water and removing organic solvent as required. Also claimed are substrates coated with (I).
