| 摘要 |
<p>Compounds useful as cement set retarding additives have been found which have the formula wherein (a) n is 0 to 15; (b) A, B, C, and D are each independently selected from (i) hydrogen; (ii) methylenephosphonic acid and salts thereof; (iii) 2-hydroxy-3(trialkylammonium halide) propyl moieties wherein each alkyl moiety has from 1 to 5 carbon atoms; and (iv) a moiety of the formula wherein R is an unsubstituted or inertly substituted alkyl group having 1 to 6 carbon atoms, or salts thereof; such that at least one of A, B, C, and D is (ii) and at least one is (iii). 31,888-F</p> |
