The present invention relates to an additive for hydraulically setting compositions, comprising a colloidally disperse preparation of at least one salt of a mono- or polyvalent metal cation and of at least one compound which is able to release an anion which forms a low-solubility salt with the metal cation, and of at least one polymeric sulphonated dispersant. The additive is suitable particularly as a slump retainer.

The present invention relates to an additive for hydraulically setting compositions, comprising a colloidally disperse preparation of at least one water-soluble salt of a polyvalent metal cation, at least one compound capable of releasing an anion which forms a sparingly soluble salt with the polyvalent metal cation, and at least one polymeric dispersant which comprises anionic and/or anionogenic groups and polyether side chains.

The present invention relates to an additive for hydraulically setting compositions, comprising a colloidally disperse preparation of at least one water-soluble salt of a polyvalent metal cation, at least one compound capable of releasing an anion which forms a sparingly soluble salt with the polyvalent metal cation, and at least one polymeric dispersant which comprises anionic and/or anionogenic groups and polyether side chains.

Amphiphilic macromolecules having repeating structural units: structural units to adjust molecular weight and molecular weight distribution and charging property effects, high stereo-hindrance structural units, and amphiphilic structural units, which are suitable for fields such as oil field well drilling, well cementation, fracturing, oil gathering and transfer, sewage treatment, sludge treatment and papermaking, etc., and can be used as an oil-displacing agent for enhanced oil production, a heavy oil viscosity reducer, a fracturing fluid, a clay stabilizing agent, a sewage treatment agent, a papermaking retention and drainage aid or a reinforcing agent, etc.

Methods for plasticizing cementitious mixtures having relatively high water/cement ratio (at least 0.40 or higher) are surprisingly improved in terms of dosage efficiency, compared to conventional “superplasticizer” polycarboxylate polymers, when the comb-type carboxylate copolymer is formed from two different polyether side chains, specifically selected monomer constituents: (A) first polyoxyalkylene monomer represented by structural formula (R.sup.1)(R.sup.3)C═C(R.sup.2)((CH.sub.2).sub.m(CO).sub.nO(CH.sub.2).sub.o(AO).sub.pR.sup.4) wherein (AO).sub.p represents linear alkylene oxide and p is an integer of 5-23; (B) second polyoxyalkylene monomer represented by structural formula (R.sup.1)(R.sup.3)C═C(R.sup.2)((CH.sub.2).sub.m(CO).sub.nO(CH.sub.2).sub.o(AO).sub.qR.sup.4) wherein (AO).sub.q represents linear alkylene oxide groups and q is an integer of 20 to 200; (C) unsaturated carboxylic acid monomer represented by (R.sup.5)(R.sup.7)C═C(R.sup.6)(C(O)OM) wherein M represents an alkali metal, and the ratio of component A to component B is 20:80 to 50:50; and, optionally, (D) a water-soluble monomer represented by (R.sup.8)(R.sup.9)C═C(R.sup.10)(X) wherein R.sup.8, R.sup.9, and R.sup.10 each represent hydrogen or methyl group, and X represents C(O)NH.sub.2, C(O)NHR.sup.11, C(O)NR.sup.12R.sup.13, OR.sup.14, SO.sub.3H, C.sub.6H.sub.4SO.sub.3H, or C(O)NHC(CH.sub.3).sub.2CH.sub.2SO.sub.3H, or mixture thereof, wherein R.sup.11, R.sup.12, R.sup.13, and R.sup.14 each represent a C.sub.1 to C.sub.5 alkyl group.

The present invention discloses a polycarboxylic acid water-reducing agent with high adaptability to temperature and a preparation method for preparing the same. The polycarboxylic acid water-reducing agent is prepared by introducing an unsaturated macromonomer D with a temperature-sensitive side chain which could be bonded to the backbone of the polycarboxylic acid through free radical polymerization. The polycarboxylic acid water-reducing agent prepared by the invention has an adsorption group density that can be automatically adjusted with the change of ambient temperature, and thereby shows similar dispersing capability and dispersion retention capability at different ambient temperatures, demonstrating high adaptability to different ambient temperatures. It can be used in a larger temperature range with a constant dosage, which is beneficial to further popularization and application of the polycarboxylic acid water-reducing agent in regions of different climates.

This document relates to methods for improving the tensile and elastic properties of cement of an oil well using cement compositions that contain sliding-ring polymer additives. The cement compositions containing the sliding-ring polymer additives exhibit increased stiffness while having a minimum impact on compressive strength, as compared to the same cement without the sliding-ring polymer additive.

This document relates to methods for improving the tensile and elastic properties of cement of an oil well using cement compositions that contain sliding-ring polymer additives. The cement compositions containing the sliding-ring polymer additives exhibit increased stiffness while having a minimum impact on compressive strength, as compared to the same cement without the sliding-ring polymer additive.

A preparation method of a powdery polycarboxylate superplasticizer is provided, including: mixing a superplasticizer monomer with water to produce a mixture, heating and melting the mixture to produce a melt system; carrying out a bulk polymerization reaction by adding an initiator, a chain transfer agent and an unsaturated carboxylic acid into the melt system, forming a polycarboxylate superplasticizer precursor; and neutralizing and pulverizing the polycarboxylate superplasticizer precursor to produce a powdery polycarboxylate superplasticizer. Water is added in the bulk polymerization and reacts with the superplasticizer monomer and the unsaturated carboxylic acid. While the bulk polymerization reaction is guaranteed to be efficiently carried out and the solid polycarboxylate superplasticizer is formed, the viscosity of a bulk polymerization reaction system is reduced. The superplasticizer is suitable for dry-mixed mortar, high-efficiency concrete and other products.

A preparation method of a powdery polycarboxylate superplasticizer is provided, including: mixing a superplasticizer monomer with water to produce a mixture, heating and melting the mixture to produce a melt system; carrying out a bulk polymerization reaction by adding an initiator, a chain transfer agent and an unsaturated carboxylic acid into the melt system, forming a polycarboxylate superplasticizer precursor; and neutralizing and pulverizing the polycarboxylate superplasticizer precursor to produce a powdery polycarboxylate superplasticizer. Water is added in the bulk polymerization and reacts with the superplasticizer monomer and the unsaturated carboxylic acid. While the bulk polymerization reaction is guaranteed to be efficiently carried out and the solid polycarboxylate superplasticizer is formed, the viscosity of a bulk polymerization reaction system is reduced. The superplasticizer is suitable for dry-mixed mortar, high-efficiency concrete and other products.