Process for preparing protective-colloid-stabilized polymers by continuous emulsion polymerization

A process for preparing protective colloid-stabilized polymers based on esters and ethylene and optionally other comonomers as polymerizable monomers, in the form of aqueous polymer dispersions or water-redispersible polymer powders, by means of free-radical-initiated continuous emulsion polymerization to form an aqueous polymer dispersion and, for polymer powders, drying the resultant polymer dispersion, comprising

• emulsion polymerizing said polymerizable monomers in at least two pressurized reactors arranged in series at a temperature of from 40° C. to 100° C. and at a pressure of from 5 bar to 100 bar, the pressure of said first reactor higher than the pressure of said second reactor, to a residual monomer content of less than 3% by weight, and further polymerizing in at least one unpressurized reactor at a temperature of from 20 to 60° C. and at a pressure of <1 bar, wherein
• the polymerization is initiated using a redox system made from an oxidizing component and a reducing component, and where at least a portion of the total reducing component is introduced into the first pressurized reactor.