COPOLYMER FOR CEMENT ADMIXTURE, PREPARATION METHOD THEREOF AND USE THEREOF

摘要

PURPOSE: A copolymer for a cement admixture and its preparation method are provided, to obtain a copolymer exhibiting excellent dispersibility even in a high water reduction ratio with a small amount. CONSTITUTION: The copolymer comprises a constituent unit derived from an unsaturated polyalkylene glycol ether-based monomer; and a constituent unit derived from an unsaturated monocarboxylic acid-based monomer. The unsaturated polyalkylene glycol ether-based monomer contains an alkenyl group of C5 and a oxyalkylene group of C2-C18 having an average addition mol of 10-300. The cement admixture comprises the copolymer and optionally a defoaming agent. The cement composition comprises the copolymer and cement. The method comprises the step of copolymerizing monomer components containing the unsaturated polyalkylene glycol ether-based monomer and the unsaturated monocarboxylic acid-based monomer by using a chain transfer agent and/or adjusting pH to be 5 or more after the copolymerization.