REDISPERSIBLE POLYMER POWDER

The present invention pertains to a water-redispersible polymer powder based on at least one modified natural latex. The modified natural latex can be obtained by mixing natural latex with at least one radical initiator and/or oxidizing agent, by mixing and reacting natural latex with at least one olefinically unsaturated monomer and with at least one radical initiator, and/or by mixing natural latex with at least one filler. Preferably, the polymer powder contains up to about 95 wt. % of least one natural latex, about 0 to 50 wt. % of at least one protective colloid, about 2 to 70 wt. % of at least one filler and/or anti-caking agent, as well as optionally further additives. In addition, the invention pertains to a process for the preparation of the polymer powder, the use thereof as an additive in building material compositions, as well as building material compositions containing the polymer powder.