Method for synthesizing slow release type high slump loss resistant polycarboxylate water reducer at normal temperature

Abstract

The invention relates to a method for synthesizing a slow release type high slump loss resistant polycarboxylate water reducer at a normal temperature. The method comprises the following steps: (1) adding an TPEG macromonomer, maleic anhydride and water into a reaction kettle, stirring and dissolving to obtain a uniform mixed solution a; (2) dropwise adding a mixed solution b prepared from ammonium persulfate and hydrogen peroxide; (3) dropwise adding a mixed solution c prepared from sodium dithionite and mercaptopropionic acid; (4) dropwise adding a mixed solution d prepared from acrylic acid and sodium methallyl sulfonate; (5) after dropwise adding, performing heat preservation for 2-2.5 hours to complete reaction; (6) regulating the pH to be 6-7 to obtain light yellow transparent liquid, namely the polycarboxylate water reducer. With the adoption of a combined oxidation-reduction system, the reaction can be carried out at room temperature, the appropriate reaction temperature is within the scope of 5-35 DEG C, and heating is not needed in the synthesizing process. The prepared polycarboxylate water reducer has the characteristics of slow release, high slump loss resistance and the like. The polycarboxylate water reducer is wide in application range, low in requirement for production process and suitable for industrialized mass production.

Description

technical field [0001] The invention belongs to a production method of a concrete water-reducing agent, in particular to a method for synthesizing a slow-setting high-slump polycarboxylate water-reducer at room temperature by using a composite redox system. Background technique [0002] At present, polycarboxylate superplasticizers are widely used in the concrete industry due to their low dosage, high water reducing rate, and high strength, and the annual demand is gradually increasing. It has gradually replaced naphthalene, melamine, and amino The trend of sulfonic acid-based superplasticizers. However, for the current synthesis of polycarboxylate water reducers, thermal synthesis is usually used, and the synthesis temperature is between 60 and 90°C, and some are even higher. The relatively low solid content of the synthesized water reducer is relatively low. In the process of transportation, the synthesis and sales costs of synthetic polycarboxylate water reducers are uni...

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Problems solved by technology

However, for the current synthesis of polycarboxylate water reducers, thermal synthesis is usually used, and the synthesis temperature is between 60 and 90°C, and some are even higher. The relatively low solid content of the synthesized water reducer is relatively low. In the process of transportation, the synthesis and sales costs of synthetic polycarboxylate water reducers are unintentionally increased, forcing some consumers to use naphthalene-based water reducers that are more polluting to the environment, and such water reducers have already been sold in Europe. It is restricted in some countries, and may be restricted in China in the near future

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