RANDOM COMB POLYMERS, PROCESS FOR PREPARING THEM AND THEIR USE

The invention relates to statistic comb polymers that are obtainable by the radical copolymerization of a vinylic poly(alkylenoxide) compound (A) with an ethylenically unsaturated monomer compound (B) according to the catalytic chain transfer method (CCT). The inventive comb polymers are extremely suitable for hydraulic binder suspensions based on cement, lime, gypsum and anhydrite as they have, for the same dosage, an improved water reducing power over conventional flow agents based on prior art comb polymers. The corresponding building material mixtures are characterized by a substantially reduced stickiness and plastic viscosity once said comb polymers are added, which dramatically improves the plasticity of very cement-rich building material mixtures, such as concretes. The building material mixtures using the inventive flow agents have a considerably increased slump flow at identical slump as compared to those comprising conventional poylcarboxylate ether flow agents. The building material mixtures and especially concretes, at identical water/cement ratio, have an increased shear-thinning behavior as compared to conventional concretes while not having the tendency to segregate ("bleed").