| 摘要 |
PROBLEM TO BE SOLVED: To provide a copolymer capable of exhibiting water-reducing property, workability and the like in a cement composition and the like at high level, and having a simple molecular structure.SOLUTION: A polyalkylene glycol-based block copolymer has an essential structure in which a polymer chain by unsaturated carboxylic acid-based monomer units (A) and a polymer chain by monoalkoxypolyalkylene glycol-based constitutional units (B) are bound through a binding site (X) and in which the polymer chain (A) and the polymer chain (B) are bound in an order of the polymer chain (A) and the polymer chain (B) through the binding site (X), an average introduced molar number of the unsaturated carboxylic acid units in the polymer chain (A) is 20 or more, a terminal of the polymer chain (A) not binding to the binding site (X) is a hydrogen, an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 1 to 10 carbon atoms, and an average addition molar number of an oxyalkylene group of the polyalkylene glycol-based constitutional units in the polymer chain (B) is 75 or more. |
