| abstract |
The present invention provides an aqueous dispersion comprising gypsum and a surface-active, anionic compound, wherein the surface-active compound is a phosphoric acid ester selected from the group consisting of (1) an acidic phosphoric acid ester of the formula: <IMAGE> wherein R1 and R2 are the same or different and are alkyl poly(oxyethylene), alkyl poly(oxypropylene), alkylphenoxy- alkyl or alkylphenyl polyoxyalkyl radicals, (2) a monophosphoric acid ester of a mono- or dihydroxyalkylurea or of an alkoxylated mono- or dihydroxyalkylurea, and (3) a monophosphoric acid ester of a polyalkoxylated amine, in which several hydroxyl groups can be esterified with phosphoric acid. |