Patent ID: 7288580

Claim:
A setting accelerant and water-redispersible polymer powder composition which accelerates the setting of hydraulically settable cementitious compositions, comprising an admixture of the separate components a) one or more water-redispersible polymers prepared by polymerizing a monomer mixture consisting of a)i) from 90 weight percent to 100 weight percent of one or more monomers selected from the group consisting of vinyl esters of optionally branched C 1-15 alkylcarboxylic acids; (meth)acrylic esters of alcohols selected from the group consisting of methanol, ethanol, propanol, n-butanol, 2-ethylhexanol, and norbornol; vinyl aromatics; monoolefins; diolefins; and vinyl halides, and a)ii) optionally up to 10 weight percent of one or more auxilliary monomers selected from the group consisting of ethylenically unsaturated carboxamides, ethylenically unsaturated carbonitriles, diesters of fumaric acid, diesters of maleic acid, methyl methacrylamidoglycolate, N-methylolacrylamide, -methylolmethacrylamide, N-methylol(meth)acrylamide alkyl ethers, N-methylol(meth)acrylamide alkyl esters, and hydroxyalkyl(meth)acrylates; b) from 0.1 to 25 weight percent of at least one alkanolamine-functional setting accelerant selected from the group consisting of NR 3 , R 2 N—(CH 2 ) 2 —NR 2 and singly amino-terminated or doubly amino-terminated polyoxyalkylene glycols having C 1-3 alkylene groups, where the radicals R each independently are H, C 1-6 alkyl, or C 1-6 hydroxyalkyl, the accelerants optionally present as salts of an inorganic or organic acid, and wherein in the compounds NR 3 , from 1 to 3 R are hydroxyethyl radicals, 2-hydroxypropyl radicals, or mixtures thereof; in the compounds R 2 N—(CH 2 ) n —NR 2 , from 1 to 4 R are hydroxyethyl radicals, hydroxypropyl radicals, or 2-hydroxypropyl radicals; and wherein the polyxoyalkylene glycols are polyoxyethylene glycols, polyoxypropylene glycols, or EO-PO copolymer glycols, said redispersible polymer powder composition further comprising c) at least one protective colloid, d) optionally one or more antiblocking agent(s), and wherein said composition is prepared by adding said accelerant to an aqueous dispersion of protective colloid-containing after polymer polymerization is completed and spray drying the composition, or the polymer is spray dried in the form of an aqueous dispersion in the presence of a protective colloid to form a redispersible polymer powder, and the accelerant is admixed in powder form with the redispersible polymer powder.