Patent ID: 8263688
Filing Date: 2012-09-11
Classification: C04B,C08F

Abstract:
1. A dispersion-retaining agent for a hydraulic composition, comprising a copolymer obtained by polymerizing monomers, said copolymer comprising monomer 1 represented by formula (1): wherein R AO represents an oxyalkylene group having 2 carbon atoms, n represents the number of AO units added on the average per molecule and is a number of 5 to 50, R q represents an integer of 0 to 2, and p represents 0 or 1, and monomer 2 represented by formula (2): wherein R in the constituent monomers of the copolymer, the proportion of the monomer 1 is 28 to 78% by weight when n in formula (1) is 5 to 50, in the constituent monomers of the copolymer, the total proportion of the monomers 1 and 2 is 90% by weight or more, at least a part of the monomer 2 are monomer 2 wherein R in the constituent monomers of the copolymer, the proportion of monomer 2 is 22 to 72 wt %, and in the constituent monomers of the copolymer, the proportion of monomers having at least one group selected from the group consisting of a carboxylic acid group, a phosphoric acid group and a neutralized group thereof is 2.5% by weight or less.