ADDITIVE FOR CEMENT COMPOSITION

摘要

PROBLEM TO BE SOLVED: To obtain an additive having an excellent rust-inhibitory effect and also high safety with respect to the environment and human body by preparing an additive that contains a polyamine-based amphoteric surfactant having a specific structure. SOLUTION: This additive contains a polyamine-based amphoteric surfactant represented by the formula (1) [wherein: R1 is an 8-22C alkyl, alkenyl, alkylaryl or aryl group; R2 is H or functional group represented by the formula (CpH2p)COOM2; R3 is H or a functional group represented by the formula (CqH2q)COOM3; each of (m), (n), (p) and (q) is an integer of 1-6; and each of M1, M2 and M3 is H, a basic nitrogen-containing group or a metal cation, and M1, M2 and M3 are the same or different]. The preparation of the comphoteric surfactant, for example, comprises: subjecting a carboxylic ester, acrylonitrile, or the like to addition to an N-alkylpolymethylenediamine compound; thereafter subjecting the addition product to saponification to form the objective surfactant in the form of a sodium salt, or the like. The amount to be added to such an additive is 0.01-10 wt.% or preferably 0.02-5 wt.% of the total amount of binding materials such as cement.