MULTISTAGE PREPARATION OF AQUEOUS POLYMER DISPERSIONS FOR PRODUCING COMPOSITE FILMS

摘要

Described is a process for preparing an aqueous polymer dispersion from ethylenically unsaturated, free-radically polymerizable monomers. In a first stage, a first polymer is prepared by free-radical emulsion polymerization. In a second stage, an aqueous polymer dispersion is prepared in the presence of the first polymer. The monomers of the first stage comprise monomers with acid groups. The polymerization of the first stage takes place at a low pH of less than 5. The acid groups of the first polymer are neutralized during the polymerization of the second stage to an extent such that the pH of the polymer dispersion at the end of the second stage is greater than 5. The aqueous polymer dispersions can be used as adhesives for producing composite films.