Cement dispersant comprising a naphthalenesulfonic acid polycondensate and at least one of a phosphorylated polycondensate and a polycarboxylate ether, and construction composition

Abstract

A cement dispersant comprises component i) and at least one of components ii) and iii). Component i) is a naphthalenesulfonic acid polycondensate being obtainable by a condensation reaction of i-1) a naphthalenesulfonic acid, i-2) an alkoxylated hydroxyaryl compound having a polyoxyalkylene chain with 3 to 130 oxyalkylene units, and i-3) formaldehyde, in a weight ratio of i-1):i-2) of 95:5 to 60:40. Component ii) is a phosphorylated polycondensate being obtainable by a condensation reaction of ii-1) an aromatic compound having a phosphate moiety, ii-2) an alkoxylated hydroxyaryl compound having a polyoxyalkylene chain with 3 to 130 oxyalkylene units, and ii-3) formaldehyde, in a weight ratio of ii-1):ii-2) of 2:98 to 40:60. Component iii) is a polycarboxylate ether having a carbon-chain backbone with anionic and/or anionogenic groups and polyoxyalkylene side chains having an average of 3 to 130 oxyalkylene units. The cement dispersant has a good dosage efficiency and a good balance between effectiveness and cost without compromising compressive strength, while avoiding compatibility issues and viscosity increase of the dispersant.

Dependencies are inferred from the claim text.