The invention relates to the use of water-soluble polymers, consisting of a) monoethylenically unsaturated monomers consisting of acidic groups in an acidic, partially or fully neutralized form and b) other monomers which can be copolymerized with monomers a) as a drying agent for the production of redispersion power and/or powdery polymer dispersing agents. The water-soluble polymers contain at least 20 wt. % monomers (a) and a maximum of 8O wt. % monomers (b) and are supplied to the production process in the form of aqueous solutions in amounts of up to 50 wt. % maximum, enabling powder, polymer products with a residual moisture of