Use of polypropylene glycol as a shrinkage-reducing additive in dispersion powder compositions for construction materials

A redispersible dispersion powder composition for construction materials, said composition consisting essentially of

• a) a base polymer selected from the group consisting of vinyl ester homopolymers, vinyl ester copolymers of vinyl acetate, or vinyl ester copolymers of saturated C.sub.3 -C.sub.8 alkyl-carboxylic acids with other vinyl ester, vinyl ester/ethylene copolymers;
• vinyl ester/ethylene/vinyl chloride copolymers;
• vinyl ester/vinyl chloride copolymers;
• vinyl ester/maleic acid ester copolymers;
• vinyl ester/fumaric acid ester copolymers, homopolymers of methacrylic acid esters, homopolymers of acrylic acid esters, homopolymers of styrene, copolymers of styrene and acrylic acid esters, copolymers of styrene and methacrylic acid esters and copolymers of vinyl chloride and ethylene,
• b) either
• b1) 2 to 20% by weight, based on the base polymer, of polyvinyl alcohol having a degree of hydrolysis of 85 to 94 mol % and a Hoppler viscosity of 2 to 40 mPa.s or
• b2) 2 to 20% by weight, based on the base polymer, of alkali metal salts or alkaline earth metal salts of phenolsulfonic acidformaldehyde condensation products, and
• c) 3 to 30% by weight, based on the total weight of polymeric components, of antiblocking agents, and
• d) 2 to 20% by weight, based on the base polymer of polypropylene glycol.