A method for inerting a swellable clay and/or for reducing or inhibiting adverse effects of swellable clays on the effectiveness of dispersants in mineral binder compositions, includes adding a comb polymer to a mineral binder composition. The comb polymer includes: at least one poly(alkylene oxide) side chain-bearing monomer unit without ionic groups, optionally at least one cationic monomer unit, optionally at least one anionic monomer unit, and optionally, at least one non-ionic monomer unit.

The present invention relates to a continuous process for preparing a comb polymer, without organic solvent, by esterification and/or amidification of an acidic homopolymer or copolymer, which consists in performing the esterification and/or amidification of said homopolymer/copolymer by reaction at elevated temperature in the mixing and transportation zone of a tubular reactor, optionally equipped with a water removal system, in the presence of at least one poly(alkylene glycol) in solid or molten form and of an antioxidant, said esterification and/or amidification taking place at a temperature greater than or equal to 170 C.

The present invention relates to a hydraulic composition comprising: at least one hydraulic binder; at least one first water-reducing additive comprising at least one phosphonic amino-alkylene group; at least one second water-reducing additive comprising at least one polymer with a comb structure, the concentration by weight of dry extract of the second additive being from 25% to 100% of the concentration by weight of dry extract of the first additive.

A concrete comprising such a hydraulic composition and a fluidizing mix for such a hydraulic composition are two other aspects of the present invention.

The present invention discloses a phosphorylated polycondensate high-performance water-reducing agent with a phosphorylated melamine derivative, instead of a conventional carboxyl group or sulfonic group, as a main adsorption group. The use of aryl alkoxypolyether as a side chain of the polymer provides a strong steric effect to improve the dispersibility and dispersion-retaining properties of the polymer. A polycondensate high-performance water-reducing agent and a method for preparing the same provided by the present invention have excellent overall performance, high adaptability for current low-grade raw materials of concrete, strong market demands, and vast application prospects. Additionally, the polycondensate has an advanced preparation process provided with the characteristics of industrially scalable production, which offers the prospect of a core technology in the field of water-reducing agent of concrete so as to promote development of the industry.

A comb polymer is used for increasing the flow rate and/or reducing the viscosity of a mineral binder composition, where the comb polymer has a main chain including acid groups and there are pendent chains linked to the main chain, and where the average number-average molar mass of all of the pendent chains is from 120 to 1000 g/mol and the molar ratio of the acid groups to the side chains is in the range from 0.5 to 2.

An admixture for cement, including: A) a comb polymer comprising the following partial structural units or consisting thereof: a) a mole fractions of a partial structural unit S1 of formula (I)

##STR00001## b) b mole fractions of a partial structural unit S2 of formula (II)

##STR00002## where M, R.sup.u, R.sup.v, m and R.sup.1 are as defined in the invention; and B) optionally, alkanol amine.

The admixture for cement can provide remarkable improvement effects, particularly in milling aid effect, water-reducing properties, slump, fluidity and strength, for cements containing inferior or cheap mineral aggregate.

The present invention provides compositions useful as a replacement for cellulose ether in cement, plaster or mortar compositions comprising i) nonionic or substantially nonionic vinyl or acrylic brush polymers having pendant or side chain polyether groups, and having a relative weight average molecular weight of from 140,000 to 50,000,000 g/mole, and ii) aromatic cofactors containing one or more phenolic groups, such as catechol tannins, phenolic resins, polyphenolics, and napthhols or, in combination, one or more aromatic groups with at least one sulfur acid group, such as naphthalene sulfonate aldehyde condensate polymers, poly(styrene-co-styrene sulfonate) copolymers, and lignin sulfonates, preferably branched cofactors, including phenolic resins, aldehyde condensate polymers and lignin sulfonates. The compositions may comprise a dry powder blend of i) and ii), one dry powder of both i) and ii), or an aqueous mixture.

The present invention provides compositions useful as a replacement for cellulose ether in cement, plaster or mortar compositions comprising i) nonionic or substantially nonionic vinyl or acrylic brush polymers having pendant or side chain polyether groups, and having a relative weight average molecular weight of from 140,000 to 50,000,000 g/mole, and ii) aromatic cofactors containing one or more phenolic groups, such as catechol tannins, phenolic resins, polyphenolics, and napthhols or, in combination, one or more aromatic groups with at least one sulfur acid group, such as naphthalene sulfonate aldehyde condensate polymers, poly(styrene-co-styrene sulfonate) copolymers, and lignin sulfonates, preferably branched cofactors, including phenolic resins, aldehyde condensate polymers and lignin sulfonates. The compositions may comprise a dry powder blend of i) and ii), one dry powder of both i) and ii), or an aqueous mixture.

The present invention relates to the use of a sequenced polymer as an agent for monitoring the filtrate in a fluid injected under pressure into an oil rock, wherein the fluid comprises solid particles and/or is brought into contact with solid particles within the oil rock after being injected, the polymer comprising at least three blocks, including: at least one first block which is adsorbed, preferably irreversibly, onto at least some of the particles (p); a second block (R) having a composition other than that of the first and a mean molecular weight of more than 10,000 g/mol, and which is soluble in the fluid (F); and at least one third block of type (A) or type (B).

This invention relates to the use, in a foamy aqueous suspension of calcium sulfate hemihydrate, as an agent having the dual function of being a dispersing agent and an anti-defoaming agent, of a comb polymer made up of (meth)acrylic acid, a monomer which is an alcoxy- or hydroxy-polyalkylene glycol, and an ester of (meth)acrylic acid. It also relates to the aqueous suspensions thereby formed, and the plasterboard manufactured from 2 sheets of paper containing a body resulting from the drying of said suspensions.