Preparation method of mud resisting and slump retaining type phosphate group containing polycarboxylate superplasticizer

Abstract

The invention discloses a preparation method of a mud resisting and slump retaining type phosphate group containing polycarboxylate superplasticizer. The preparation method comprises the following specific steps that 1, a halogen containing polycarboxylate superplasticizer prepolymer is prepared, wherein halogen containing unsaturated monomers, halogen containing unsaturated acid small monomers and halogen containing unsaturated polyether macromonomers or unsaturated ester macromonomers are subjected to an oxidation-reduction radical polymerization reaction to obtain the halogen containing polycarboxylate superplasticizer prepolymer; 2, the halogen containing polycarboxylate superplasticizer prepolymer and alkyl phosphate are subjected to an Arbuzov reaction to obtain a phosphate group containing copolymerization product, the pH value is adjusted after reacting is completed, water is added, and then the polycarboxylate superplasticizer is obtained. The mud resisting and slump retaining type phosphate group containing polycarboxylate superplasticizer prepared through the method has the advantages of being low in mixing amount, high in water reducing ratio, long in slump retaining time and high in mud resisting property, can avoid the adverse effect brought by mud containing aggregate in concrete and is simple in synthesis process, easy to control and low in production cost.

Description

technical field [0001] The invention relates to the technical field of a polycarboxylate water-reducer for cement concrete, in particular to a preparation method of a mud-resisting slump-retaining polycarboxylate-containing polycarboxylate water-reducer. Background technique [0002] Polycarboxylate superplasticizers are more and more widely used in concrete engineering because of their excellent properties such as low dosage, high water reducing rate, good slump retention, strong molecular structure adjustability, and environmental protection. However, a large number of engineering examples and studies have shown that compared with traditional naphthalene-based, melamine-based and sulfamic acid-based water-reducers, polycarboxylate-based water-reducers are more sensitive to the clay content of aggregates. The mud in the mixture will absorb the polycarboxylate superplasticizer. With the increase of the mud content, the water reducing and dispersing ability of the polycarboxy...

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Problems solved by technology

[0004] Chinese patent document CN 105418857A reports a preparation method of a phosphate-based polycarboxylate water reducer, which is to firstly carry out copolymerization of unsaturated polyether macromonomer, unsaturated carboxylic acid ester, and unsaturated alcohol in an organic solvent The polycarboxylate superplasticizer prepolymer is obtained by reaction, and then the polycarboxylate superplasticizer prepolymer is phosphorylated and modified, and then in the presence of an acidic aqueous solution, the carboxylate group on the phosphorylated modified product is Hydrolyze the mass, remove the organic solvent, and finally neutralize to obtain the polycarboxylate water reducer containing phosphate groups, but the production process of this invention is complicated, the conversion rate is not high, the production cost is high, and a large amount of organic solvents are used , not conducive to large-scale production and application

[0005] Chinese patent document CN 104261719A uses unsaturated phosphate ester monomer, unsaturated acid monomer, polyether macromonomer, chain transfer agent, initiator and water as raw materials, and adds dropwise at 40-80°C for 4-6h, A polycarboxylate water reducer with a phosphate structure was prepared by keeping it warm for 2 hours, but the phosphoric acid group in the unsaturated phosphate monomer used in this invention has a certain chain transfer effect, and directly participating in the copolymerization reaction of the water reducer may bring The disadvantage that the structure and molecular weight of the water reducer cannot be accurately controlled

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