Patent ID: 7253220

Claim:
An admixture for cement comprising four components of a copolymer (A), an unsaturated (poly)alkylene glycol ether monomer (a), a non-polymerizable (poly)alkylene glycol (B) having no alkenyl group, and a polymer (C) having an oxyalkylene group or a polyoxyalkylene group and a carboxyl group, which is different from the copolymer (A), at ratios of the unsaturated (poly)alkylene glycol ether monomer (a) to the copolymer (A) in a range of 1 to 100% by mass, the non-polymerizable (poly)alkylene glycol (B) having no alkenyl group to the copolymer (A) in a range of 1 to 50% by mass, and the polymer (C), which is different from the copolymer (A), having an oxyalkylene group or a polyoxyalkylene group and a carboxyl group to the copolymer (A) in a range of 1 to 10000% by mass, wherein the copolymer (A) contains a constituent unit (I) derived from the unsaturated (poly)alkylene glycol ether monomer (a) and a constituent unit (II) derived from a maleic acid monomer (b) at ratios of the constituent unit (I) and the constituent unit (II) in a range of 1% by mass or more, respectively, in the entire constituent units, and the unsaturated (poly)alkylene glycol ether monomer (a) is represented by the general formula (1): Y 1 O(R 1 O) n R (1) wherein Y 1 represents an alkenyl group containing 2 to 4 carbon atoms, R 2 represents a hydrogen atom or a hydrocarbon group containing 1 to 30 carbon atoms, R 1 O represents one or more species of oxyalkylene groups containing 2 to 18 carbon atoms, and n represents the average molar number of addition of the oxyalkylene groups and is a number of 1 to 500.