| abstract |
A flocculation, sedimentation, dehydration or retention composition comprising a dispersion of about 10 to 50% concentration by weight of a polymeric Mannich base in a mixture of water and a water-insoluble liquid, the Mannich base comprising an H-active polymer carrying radicals of a reaction with formaldehyde and a primary or secondary alkyl- or hydroxyalkylamine wherein the alkyl groups have up to about 18 carbon atoms. The amine is preferably dimethylamine or diethylamine and is used in approximately the same molar amount as the formaldehyde. The polymer preferably comprises acrylamide units and the polymerization may be effected either before or after reaction with the formaldehyde and amine. |