| abstract |
The invention provides a redispersibte dispersion powder composition comprising a) a base polymer selected from the group consisting of vinyl ester polymers, styrene polymres, acrylate polymers and vinyl chloride polymers, b) from 2 to 15% by weight, based on the weight of the base polymer, of polyvinyl alcohol having a degree of hydrolysis of from 85 to 95 mol % and a Hoppler viscosity of from 2 to 25 mPa.s, c) from 3 to 30% by weight, based on the total weight of polymeric components, of fine antiblocking agent, and d) from 1 to 15% by weight, based on the weight of the base polymer, of an aminofunctional polyvinyl alcohol soluble in cold water and having a Hoppler viscosity of from 1 to 20 mPa.s and a saponification number of from 0 to 250, which comprises residues of aminofunctional vinyl units of the formula CH2=CH-(CH2)x-NH2, wherein x is a number of from 0 to 4. The dispersion powder compositoin of the invention is particularly suitable for use in building materials, in particular, dry mortars comprising Portland cement as inorganic binder, and leads in these to increased adhesive strength of the mortar. |