| 主权项 |
1. A slump retaining agent for a hydraulic composition, which consists of a copolymer obtained by polymerization of:
a) at least one anionic monomer comprising a polymerizable unsaturated function and a carboxylic group, b) at least one macromonomer having a formula (I):
Rf-[(EO)m-(PO)n-(BO)p]-Rf′ (I)in which:[(EO)m-(PO)n-(BO)p] represents at least one polyalkoxylated chain consisting of alkoxylated units, arranged in blocks, randomly or alternatively, selected from the group consisting of ethoxylated units EO, propoxylated units PO and butoxylated units BO,m, n and p represent, independently of each other, 0 or an integer ranging from 1 to 250 (inclusive), the sum of m, n and p being between 10 and 250,Rf represents a radical containing a polymerizable unsaturated function andRf′ represents hydrogen or an alkyl group containing from 1 to 4 carbon atoms and c) at least one nonionic cross-linking monomer comprising at least two polymerizable unsaturated functions and an ester group,
wherein said copolymer has a molecular weight of greater than 400,000 g/mol as determined by SEC; andwherein said slump retaining agent is not a water reducing agent according to standard ADVJUVANT NF EN 934.2. |
