Abstract: A copolymer that has sufficient dispersibility to various kinds of cements, including those having low fluidity (difficult cement). The copolymer is obtained by polymerizing monomer components including an unsaturated (poly)alkylene glycol ether monomer (a), an unsaturated carboxylic acid monomer (b), and an unsaturated cross-linkable monomer (c) or an unsaturated cross-linkable monomer (d). The unsaturated cross-linkable monomer (c) is allyl itaconate or allyl citraconate, or ester thereof. The unsaturated cross-linkable monomer (d) is an ester obtained by reaction of at least one acid, selected from the group consisting of (meth)acrylic acid, maleic acid, fumaric acid, itaconic acid, and citraconic acid and ester derived from the acids, with a (poly)alkylene glycol or a (poly)alkylene glycol ether.

Abstract: The present invention relates to a copolymer which is obviously by polymerizing monomer components comprising: (a) a compound represented by formula (A1): Y—B-0-(A-0)mR2(A1) wherein Y represents an alkenyl group containing two or more carbon atoms, B represents a C2-18 oxyalkylene group; R2 represents a hydrogen atom or a C1-30 hydrocarbon group and m represents an integer of from 0 to 300; and/or an addition product obtained by the addition of 0-8 moles of any alkylene oxide having 2 to 4 carbon atoms to one equivalent of amino residues in polyamide polyamine obtained by condensation of 1.0 moles of apolyalkylene polyamine, 0.8-0.95 mole of a dibasic acid or an ester of the dibasic acid with a lower alcohol having 1 to 4 carbon atoms, and 0.05-0.

Abstract: An object of the present invention is to provide a novel copolymer capable of exerting excellent dispersibility to various kinds of cement including cement having low fluidity (difficult cement), and a dispersant for cement and cement composition including the copolymer. The copolymer of the present invention is a copolymer obtainable by polymerizing monomer components including an unsaturated (poly)alkylene glycol ether monomer (a), an unsaturated carboxylic acid monomer (b), and an unsaturated cross-linkable monomer (c) or an unsaturated polymerizable monomer (d).