Fluidifying agents for cementitious compositions based random copolymers, compositions comprising the same, and methods for their use

A cementitious composition comprising a random copolymer corresponding to Formula I in free acid or salt form having the following types and numbers of monomer units:

• ##STR10## wherein:
• A is selected from the moieties (i) and (ii);
• --CR.sub.1 R.sub.2 --CR.sub.3 R.sub.4 -- (i)
• wherein:
• R.sub.1 and R.sub.3 are selected from C.sub.1-8 alkyl, C.sub.2-8 alkenyl, C.sub.2-8 alkylcarbonyl, C.sub.1-8 alkoxy, carboxyl and hydrogen, or R.sub.1 and R.sub.3 can together with R.sub.2 and/or R.sub.4 form a ring;
• and R.sub.2 and R.sub.4 are selected from hydrogen and C.sub.1-4 alkyl;
• and, ##STR11## wherein:
• R.sub.1 and R.sub.3 are as for (i) and R.sub.7, R.sub.8, R.sub.9 and R.sub.10 are individually selected from hydrogen and C.sub.1-6 alkyl, or R.sub.1 and R.sub.3 together with R.sub.7 and/or R.sub.8, R.sub.9 and R.sub.10 from a continuous C.sub.2-8 hydrocarbon chain joining the carbon atoms to which they are attached, the hydrocarbon chain optionally comprising at least one hetero atom and the ring optionally having at least one anionic group;
• 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 --(R.sub.5 O).sub.m R.sub.6
• R.sub.5 is a C.sub.2-8 alkylene radical;
• R.sub.6 is selected from C.sub.1-20 alkyl, C.sub.6-9 cycloalkyl 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) is from 1:10 to 10:1 and the ratio of y:z is from 5:1 to 1:100.

A method of fluidifying a cementitious composition comprising the steps of incorporating into said cementitious composition a random copolymer corresponding to Formula I in free acid or salt form having the following types and numbers of monomer units:

• ##STR12## wherein:
• A is selected from the moieties (i) and (ii);
• --CR.sub.1 R.sub.2 --CR.sub.3 R.sub.4 -- (i)
• wherein:
• R.sub.1 and R.sub.3 are selected from C.sub.1-8 alkyl, C.sub.2-8 alkenyl, C.sub.2-8 alkylcarbonyl, C.sub.1-8 alkoxy, carboxyl and hydrogen, or R.sub.1 and R.sub.3 can together with R.sub.2 and/or R.sub.4 form a ring;
• and R.sub.2 and R.sub.4 are selected from hydrogen and C.sub.1-4 alkyl;
• and, ##STR13## wherein:
• R.sub.1 and R.sub.3 are as for (i) and R.sub.7, R.sub.8, R.sub.9 and R.sub.10 are individually selected from hydrogen and C.sub.1-6 alkyl, or R.sub.1 and R.sub.3 together with R.sub.7 and/or R.sub.8, R.sub.9 and R.sub.10 from a continuous C.sub.2-8 hydrocarbon chain joining the carbon atoms to which they are attached, the hydrocarbon chain optionally comprising at least one hetero atom and the ring optionally having at least one anionic group;
• 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 --(R.sub.5 O).sub.m R.sub.6
• R.sub.5 is a C.sub.2-8 alkylene radical;
• R.sub.6 is selected from C.sub.1-20 alkyl, C.sub.6-9 cycloalkyl 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) is from 1:10 to 1.0:1 and the ratio of y:z is from 5:1 to 1:100.