摘要 |
Cement Admixture The present invention is directed to a copolymer of acrylic or methacrylic acid and a hydroxyalkyl acrylate or methacrylate, to cement admixture compositions containing said polymer and to hydraulic cement compositions containing said admixture. The copolymer is composed of from 20 to 40 mole percent of an alkali metal salt of acrylic or methacrylic acid either as the free acid or as their alkali or alkaline earth metal salt and from 60 to 80 mole percent of hydroxyalkyl acrylate or methacrylate; said polymer having a weight average molecular weight of at least 70,000. |