Method for preparing high-solid content polycarboxylate superplasticizer

Abstract

The invention discloses a method for preparing a high-solid content polycarboxylate superplasticizer. The method comprises the following steps: a) adding an unsaturated polyoxyethylene ether monomer into bottom water to prepare till the concentration is 60-75%, stirring in advance at 20-40 DEG C for pre-dissolution, and after dissolution, pumping dissolved bottom materials to a reaction kettle; b) adding a 25-30% hydrogen peroxide solution at one time in a stirring state of the reaction kettle; c) preparing a 4-10% mixed solution from a chain transfer agent and a reducing agent, slowly dropwise adding the mixed solution into the reaction kettle, after 15 minutes, starting to dropwise add a mixed solution prepared from a monomer A and a monomer B, wherein the concentration of the mixed solution of the monomer A and the monomer B is 60-75%; and d) stopping dropwise adding, keeping the temperature to age for 1 hour, adding an 30-40% alkali solution to adjust a product to be neutral, and pumping to a mother liquid storage tank. The solid content of the high-solid content polycarboxylate superplasticizer produced through normal temperature reaction without a heat resource can be up to 50-63.4%, the production efficiency of the high-solid content polycarboxylate superplasticizer is remarkably improved when being compared with that of a polycarboxylate superplasticizer with the solid content of 40%, and the storage efficiency can be improved.

Description

technical field [0001] The invention belongs to the field of concrete admixtures, and in particular relates to a method for synthesizing high-solid polycarboxylate water reducers at room temperature. Background technique [0002] In the concrete industry, polycarboxylate ether water reducers have become one of the key materials for the preparation of high performance concrete due to their high water reducing rate, good slump retention, low dosage, and environmental friendliness. At present, the synthesis technology of polycarboxylate superplasticizer is relatively mature and stable, but there are still problems such as high synthesis temperature (60-80°C), high energy consumption, long reaction time and high production cost. Therefore, the preparation of polycarboxylate superplasticizer at room temperature without heat source has become a new type of synthetic process, and many researchers have also conducted in-depth research on it, but the relative solid content of the syn...

AI Technical Summary

Problems solved by technology

At present, the synthesis technology of polycarboxylate superplasticizer has been relatively mature and stable, but there are still problems such as high synthesis temperature (60-80°C), high energy consumption, long reaction time, and high production cost.

Therefore, the preparation of polycarboxylate superplasticizer at room temperature without heat source has become a new type of synthetic process, and many researchers have also conducted in-depth research on it, but the relative solid content of the synthesized polycarboxylate superplasticizer is relatively low (20-40% ), high synthesis and transportation costs, low production efficiency, and limited development

[0003] However, the preparation method of polycarboxylic acid with high solid content (more than 60%) is still in the research and exploration stage, and there are few relevant research reports

[0004] CN102627743A provides a two-step method for synthesizing high-solid polycarboxylate water reducer after esterification and then polymerization. The synthesis takes a long time and the process is cumbersome

[0005] CN102875746A provides a direct preparation method of high-solid ether polycarboxylate water-reducer, which uses ammonium persulfate to form a water-reducer by radical copolymerization at high temperature (50-70°C) by increasing the concentration of reactants , the process reaction temperature is high, the energy consumption is large, and ammonium persulfate as the initiator system needs a higher reaction temperature to initiate the formation of free radicals

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