CEMENT ADDITIVE

摘要

The present invention concerns a cement additive containing copolymers comprising one or more constitutional units represented by formula A: (A) R1 is hydrogen, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 1 to 4 carbon atoms or an aryl group having 6 to 9 carbon atoms; R2 i s hydrogen or an alkyl group having 1 to 9 carbon atoms, an alkenyl group havi ng 1 to 9 carbon atoms or an aryl group having 6 to 9 carbon atoms; T is alkyle ne (including straight-chain and branched alkylene) having 1 to 4 carbon atoms or arylene having 6 to 9 carbon atoms; n is 0 or 1; S1 and S2 are, independentl y of one another, -OCkH2k- or -OCH2CHR3-, with the proviso that k is 2 or 3, R 3 is an alkyl group having 1 to 9 carbon atoms, an aryl group having 6 to 9 carbon atoms; and 6<_m1 + m2 <_25.