| abstract |
A random copolymer in free acid or salt form having the following types and numbers of monomer units; <IMAGE> wherein A is -CR1R2-CR3R4- (i> wherein R1 and R3 are selected from substituted benzene, C1-8alkyl, C2-8alkenyl, C2-8alkylcarbonyl, C1-8alkoxy, carboxyl and hydrogen, or R1 and/or R3 can together with R2 and/or R4 form a ring; and R1 and R4 are selected from hydrogen and C1-4alkyl; or <IMAGE> wherein R1 and R3 are as for (i) and R7, R8, R9 and R10 are individually selected from hydrogen and C1-6alkyl, or R1 and/or R3 together with R7 and/or R8, R9 and R10 form a ring optionally comprising at least one hetero atom and at least one anionic group, preferably sulphonic; M is selected from hydrogen and the residue of a hydrophobic polyalkylene glycol or a polysiloxane, with the proviso that when A is (ii) and M is the residue of a hydrophobic polyalkylene glycol, M must be different from the group -(R5O)mR6; R5 is a C2-8alkylene radical; R6 is selected from C1-20alkyl, C6-9cycloalkyl and phenyl; n, x and z are numbers from 1 to 100; y is 0 to 100; m is 2 to 100; and the ratio of x to (y + z) if from 1:10 to 10:1 and the ratio of y:z is from 5:1 to 1:100. The copolymers are useful as fluidifying agents in cementitious compositions such as concrete and mortar. |