Amphoteric polycarboxylate water reducing agent and preparation method thereof

Abstract

The invention discloses an amphoteric polycarboxylate water reducing agent and a preparation method thereof. The amphoteric polycarboxylate water reducing agent comprises the following raw materials:a polyether monomer, an initiator, a component I and a component II, wherein the component I comprises a carboxylic monomer, amide, unsaturated ester and a cationic monomer; the component II comprisesa chain transfer agent and a reducing agent; and the amphoteric polycarboxylate water reducing agent has a molecular weight of 10000 to 50000. The amphoteric polycarboxylate water reducing agent provided by the invention has high water reduction rate and excellent grout fluidity, can inhibit the slump loss of concrete, and has stable product performances. According to the invention, by selectionof the initiator to generate free radicals and combination of the component I and the component II, a polymerization reaction can be performed at a low temperature; meanwhile, the time of the reactionis reduced; energy consumption can be greatly saved; production efficiency is increased; labor cost is saved; pollution to the environment can be reduced; and the amphoteric polycarboxylate water reducing agent is applicable to industrial application.

Description

technical field [0001] The invention belongs to the technical field of water reducer and its production and preparation, and in particular relates to an amphoteric polycarboxylate water reducer and a preparation method thereof. Background technique [0002] As an important admixture of cement concrete, the quality of water reducing agent has a crucial impact on the quality of physical engineering. Among them, the polycarboxylate high-performance water reducer not only has the advantages of high water reducing rate, can improve the pore structure and compactness of concrete, but also can control the slump loss of concrete, as well as the air-entrained, retarded, and bleeding of concrete. question. In addition, it has good compatibility with different types of cement, which can make the concrete have high fluidity even at low content, and also has low viscosity and slump at low water-cement ratio. The characteristics of small changes over time. [0003] Amphoteric polycarbo...

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Problems solved by technology

[0004] In the prior art, the invention patent with the publication number CN105461253A discloses a synthesis method of an amphoteric high-performance polycarboxylate water reducer. This method needs to prepare cationic active organic monomers in advance, and the reaction conditions are strict. After post-treatment processes such as extraction, washing, decompression separation and vacuum drying, the overall reaction is relatively complicated and the cost is high; the invention patent with the publication number CN103980431A discloses a synthesis method of an amphoteric polycarboxylate water reducer. It is also necessary to prepare the allyltrimethylammonium bromide functional monomer in advance. The initial reaction temperature is an ice-water bath at a constant temperature of 5°C. The preparation process takes 63-79h. The reaction time is long, the energy consumption is high, the method is complicated and the solvent used It will pollute the environment; the invention patent with the publication number CN106188418A discloses a preparation method of an amphoteric polycarboxylate water reducer. This method needs to combine unsaturated aldehyde small monomers or unsaturated ketone small monomers with The polycarboxylate superplasticizer prepolymer containing aldehyde group or carbonyl group is obtained by free radical polymerization of unsaturated macromonomer, and then the prepolymer is subjected to Strecker reaction with sodium cyanide and ammonium chloride to obtain the main chain containing amino group and carboxyl group The amphoteric copolymerization product has experienced the process of first polymerization and then crosslinking. The synthesis process is complicated and the operability is not strong, which is not conducive to large-scale production and application.

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