| 摘要 |
<p>A cement dispersant, which can be used in a method of producing concrete with a high level of fluidity, together with low slump loss and a high early strength during the initial period of hardening, comprises water-soluble vinyl copolymers which comprise 40-80 molar % of Unit A shown below by Formula (1), 0.5-20 molar % of Unit B shown below by Formula (2), 0.2-18 molar % of Unit C shown below by Formula (3) and 2-40 molar % of Unit D shown below by Formula (4), the total content of said Units A, B, C and D in the copolymer being substantially 100 molar %, said water-soluble vinyl copolymers having weight average molecular weight (determined by gel permeation chromatograph using pullulan as the standard) from 15000 to 150000 and having ratio of weight average molecular weight to number average molecular weight from 2 to 7, Formulae (1)-(4) being: <CHEM> <CHEM> <CHEM> <CHEM> wherein R<1>, R<2> and R<3> are each independently either H or CH3; R<4> is H or an alkyl group with 1-3 carbon atoms; X is a group represented by Formula (5) or Formula (6) shown below: -SO3M<2> -O-C6H4-SO3M<3> A is the residual group obtainable by removing both hydroxyl groups from a polyether diol with the repetition number of oxyalkylene units being 5 - 109, said oxyalkylene units consisting either only of oxyethylene units or of both oxyethylene and oxypropylene units; M<1> is H, an alkali metal, an alkali earth metal, or ammonium (substituted or unsubstituted); and M<2> and M<3> are each an alkali metal, an alkali earth metal, or ammonium (substituted or unsubstituted).</p> |
