Patent ID: 8962713
Filing Date: 2015-02-24
Classification: C04B

Abstract:
1. A method comprising: adding at least one copolymer, or one of its salts, acting as a water-reducing agent to a hydraulic binder based on calcium sulfate chosen from a plaster based on calcium sulfate hemihydrate (α or β or a mixture of the two) or a binder based on anhydrous calcium sulfate, said copolymer comprising at least one unit of formula (I): and said copolymer comprising at least one unit of formula (II): in which: R1, R2 and R3 independently represent a hydrogen atom, a linear or branched C R′1, R′2 and R′3 independently represent a hydrogen atom, a linear or branched C R4 represents a linear or branched C R5 represents a radical of formula: R6 independently represents a hydrogen atom, a linear or branched C or also R5 represents a radical of formula: R7 represents a hydrogen atom, a linear or branched C R8 represents a hydrogen atom or a linear or branched C W independently represents an oxygen or a nitrogen atom or an NH radical; m is an integer from 0 to 2; n is an integer equal to 0 or 1; q is an integer equal to 0 or 1; r is an integer from 20 to 250; t is an integer from 0 to 18; and said copolymer comprising at least one unit of formula (III) originating from a monomer chosen from: for which the molar mass of said copolymer is from 15 000 to 250 000 daltons, said copolymer not comprising crosslinking units, and said copolymer comprising: the percentages being expressed as number of unit entities with respect to the total number of units present in the copolymer.