A pressure-sensitive adhesive, containing an aqueous polymer dispersion produced by emulsion polymerization, characterised in that the polymer contains monomers with a hydroxyl group or primary amino group (which are simply called hydrophilic monomers in the following) and the polymer can be obtained in that more than 70 wt.-% of the hydrophilic monomers are fed only when the polymerization mixture (a mixture of monomers and already produced polymer located in the polymerisation vessel) already contains more than 50 wt.-% of the total volume of monomers.