Process for preparing water-redispersible polymer powders for dry formulations of construction materials

A process for producing building material dry formulations, comprising:

• mixing and homogenizing one or more hydraulically-setting binders, one or more fillers, one or more protective-colloid-stabilized vinyl acetate-ethylene and/or styrene-(meth)acrylic ester copolymers in the form of water-redispersible powders and optionally one or more additives to form a dry mixture;
• wherein storage stability of the protective-colloid-stabilized vinyl acetate-ethylene and/or styrene-(meth)acrylic ester copolymers in the form of water-redispersible dry powders is improved by drying aqueous dispersions comprising protective-colloid-stabilized vinyl acetate-ethylene and/or styrene-(meth)acrylic ester copolymers, one or more water-soluble inorganic salts, and one or more desiccants;
• wherein the one or more water-soluble inorganic salts are selected from the group consisting of alkali metal sulfates;
• wherein the one or more desiccants are selected from the group consisting of polyvinyl alcohols, polyvinyl acetals, nonionic polyvinylpyrrolidones, nonionic poly(meth)acrylamides, polysaccharides and proteins;
• and
• wherein the vinyl acetate-ethylene and/or styrene-(meth)acrylic ester copolymers in the form of water-redispersible powders do not contain polyalkylene polyamine.