| 摘要 |
Compounds useful as cement set retarding additives have been found which have the formula <IMAGE> wherein A, B, C and D substituents are independently selected from hydrogen, methylenephosphonic acid, or salts thereof, hydroxypropyltrialkylammonium halide, wherein the trialkylammonium moiety contains alkyl groups having from 1 to 5 carbon atoms and n is 0 to 15, and wherein said substituents include at least one methylenephosphonic acid group, or salt thereof, and at least one hydroxypropyltrialkylammonium halide group.
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