Patent ID: 8366822

Claim:
A cement containing dry mix composition comprising a) hydraulic cement; b) a water-redispersible polymer powder (RDP) comprising a water-insoluble film-forming vinyl aromatic-diene polymer and a colloidal stabilizer, said water-insoluble film-forming polymer having an average particle size of from 200 nm to 500 nm and an amount of carboxylation of from 0.1% by weight to 2.25% by weight of at least one ethylenically unsaturated dicarboxylic acid, salts thereof, or mixtures thereof, based on the amount of copolymerized carboxyl group containing monomer based on the total weight of monomers used to make the polymer; and, c) from 0.17 to 0.35 wt. %, based on the total weight of the dry mix composition of the present invention, of a cellulose ether, whereby when the dry mix is mixed with water to form a mortar or adhesive having a mortar viscosity within the range of 400,000 to 600,000 cps mortar at 5 rpm, the amount of cellulose ether used is reduced by at least 15% as compared to the amount of cellulose ether used to achieve the same mortar viscosity when using the same cement comprising the same cellulose ether and the same amount of the same RDP made from the same polymer as the vinyl aromatic-diene latex polymer and having the same average particle size, with the exception that the latex polymer in the comparative composition has a degree of carboxylation of 2.5 wt. %.