| 摘要 |
PROBLEM TO BE SOLVED: To suppress the slump loss of a cement formulation and to attain high fluidity and a high initial strength of the cement formulation by adopting a water soluble vinyl copolymer having a specific average molecular weight, and making the formulation include two specific structural units in the specific total content and a specific mole ratio. SOLUTION: This dispersant for cement comprises a water soluble vinyl copolymer having 1,500-200,000 weight average molecular weight, in which the following requirements are met: (1) the total moles of a structural unit of formula I and a structural unit of formula II is >=60 mol% based on the whole structural units; (2) the mole ratio of (the structural unit of formula I/the structural unit of formula II) is (0.5/99.5)-(99.5/0.5). In the formulas I and II, R1 and R3 independently show H or methyl, R2 shows a 1-5C alkyl, phenyl or benzyl, A shows a (poly)oxyalkylene having 1-250 oxyalkylene repeating units and consisting of oxyalkylene units or consisting of oxyalkylene units and oxypropylene units, M1 shows H, an alkali metal, an alkaline earth metal, ammonium or an organic amine.
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