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CN-121990782-A - High-solid-content polycarboxylic acid slump retaining agent and preparation method thereof

CN121990782ACN 121990782 ACN121990782 ACN 121990782ACN-121990782-A

Abstract

The invention relates to the technical field of preparation of slump retaining agents, in particular to a high-solid-content polycarboxylic acid slump retaining agent and a preparation method thereof. The preparation method comprises the steps of carrying out nucleophilic ring-opening reaction on tea polyphenol and sulfonate monomer in inorganic base and organic solvent under inert atmosphere and ice water bath condition to prepare tea polyphenol-based polybasic sulfonic acid solubilizer, mixing polyether macromonomer, water-locking slurry-stabilizing small monomer and water, adding the solubilizer, then dropwise adding unsaturated small monomer, unsaturated carboxylic ester, initiator and molecular weight regulator to carry out copolymerization reaction, and finally regulating pH to obtain the product. According to the method, through the synergistic effect of the solubilizer with a specific structure and the water-locking slurry-stabilizing small monomer, the polycarboxylic acid slump retaining agent with the solid content up to 70% -80% and low viscosity is successfully prepared. The product can effectively improve concrete workability, prevent delayed bleeding, remarkably reduce transportation and pumping costs, and has good storage stability.

Inventors

  • GUAN MENGQIN
  • ZHANG SHENGBIAO
  • JIANG ZHUOJUN
  • WU JINSONG
  • LI WEITENG
  • ZHU QIAOYONG
  • CHEN LIYUAN
  • LI XIANGHE
  • LIU ZUNYU

Assignees

  • 科之杰新材料集团有限公司
  • 科之杰新材料集团河南有限公司

Dates

Publication Date
20260508
Application Date
20251202

Claims (10)

  1. 1. The preparation method of the high-solid polycarboxylic acid slump retaining agent is characterized by comprising the following steps: s1, under the inert atmosphere and ice water bath conditions, adding water, an organic solvent, tea polyphenol and inorganic alkali, uniformly stirring, heating, slowly dropwise adding a sulfonate monomer, and separating and purifying after the reaction is finished to obtain a tea polyphenol-based polybasic sulfonic acid solubilizer; s2, uniformly mixing and dissolving the polyether macromonomer M, the water-locking slurry-stabilizing small monomer and water, adding the prepared tea polyphenol-based polybasic sulfoacid solubilizer, uniformly mixing, dropwise adding the unsaturated small monomer, the unsaturated carboxylic ester, the initiator aqueous solution and the molecular weight regulator aqueous solution, and regulating the pH value of the system after the reaction is finished to obtain the high-solid-content polycarboxylic acid slump retaining agent.
  2. 2. The preparation method according to claim 1, wherein in the step S1, the mass ratio of the tea polyphenol, the sulfonate monomer, the inorganic base and the organic solvent is 1 (1.8-5.0): 0.5-2.0): 5-10.
  3. 3. The method according to claim 1, wherein in the step S1, the sulfonate monomer is one or more of 1, 3-propane sultone, 1, 4-butane sultone and 2, 4-butane sultone, the inorganic base is potassium hydroxide or sodium hydroxide, and the organic solvent is tetrahydrofuran.
  4. 4. The preparation method of the water-locking and slurry-stabilizing agent is characterized in that in the step S2, the mass ratio of the polyether macromonomer M to the tea polyphenol-based polybasic sulfonic acid solubilizer to the unsaturated monomer to the water-locking and slurry-stabilizing monomer to the unsaturated carboxylic acid ester is 200 (2-10), 2-15, 2-8 and 10-35.
  5. 5. The preparation method of claim 1, wherein the water-locking and slurry-stabilizing monomer is one or more of bis (3-trimethoxysilylpropyl) fumarate, bis (3-trimethoxysilylpropyl) maleate and bis (3-trimethoxysilylethyl) fumarate.
  6. 6. The method according to claim 1, wherein the unsaturated carboxylic acid ester is one or more of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, glycidyl acrylate, glycidyl methacrylate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, propylene glycol 1,3 diacrylate, amyl 1, 5-dimethacrylate, and glycerol 1, 3-dimethacrylate.
  7. 7. The preparation method of claim 1, wherein the polyether macromonomer M is one or more of 3-methyl-3-butene-1-polyethylene glycol, 2-methylallyl polyethylene glycol, ethylene glycol monovinyl polyethylene glycol ether and 4-hydroxybutyl vinyl polyoxyethylene ether with molecular weight of 600-6000; The unsaturated monomer is unsaturated carboxylic acid and/or unsaturated carboxylic anhydride, and the unsaturated carboxylic acid and/or unsaturated carboxylic anhydride is one or a combination of more of acrylic acid, methacrylic acid, itaconic acid, maleic anhydride, acrylic anhydride and itaconic anhydride.
  8. 8. The method for preparing the catalyst according to claim 1, wherein the initiator is a water-soluble inorganic peroxy initiator or a water-soluble redox initiator system; The water-soluble redox initiation system comprises an oxidant and a reducing agent, wherein the oxidant is selected from hydrogen peroxide or persulfate, and the reducing agent is selected from one or a combination of more of sodium metabisulfite, ascorbic acid, glucose or sodium bisulfate; the molecular weight regulator is one or more of thioglycollic acid, mercaptopropionic acid, mercaptoethanol, isopropanol, sodium hypophosphite, trisodium phosphate, sodium formate, sodium acetate and dodecyl mercaptan.
  9. 9. The preparation method of the water-based composite material is characterized in that in the step S1, the temperature of the ice water bath is 0-5 ℃, the temperature is raised to 30-50 ℃ after the ice water bath is uniformly stirred, the time for slowly dropwise adding the sulfonate monomer is 0.5-2h, the reaction is continued for 12-20h after the dropwise adding is finished, and then the temperature is reduced for separation and purification; in the step S2, when the polyether macromonomer M, the water-locking slurry-stabilizing small monomer and water are mixed and dissolved, the temperature is raised to 20-45 ℃, and then the temperature is regulated to the initial reaction temperature, wherein the initial reaction temperature is 5-60 ℃; the dropping time of the unsaturated monomer, the unsaturated carboxylic ester, the initiator aqueous solution and the molecular weight regulator aqueous solution is 0.5-2.0h, the reaction temperature is controlled at 5-60 ℃, the reaction is continued for 0.5-1.0h after the dropping is finished, and the pH value of the regulating system is regulated to 5-7 by alkali.
  10. 10. A slump retaining agent containing high content of solid polycarboxylic acid, which is characterized in that the slump retaining agent is prepared by the preparation method according to any one of claims 1 to 9.

Description

High-solid-content polycarboxylic acid slump retaining agent and preparation method thereof Technical Field The invention relates to the technical field of preparation of slump retaining agents, in particular to a high-solid-content polycarboxylic acid slump retaining agent and a preparation method thereof. Background Along with the continuous improvement of the requirements of modern engineering construction on the performance of concrete, the requirement of complex engineering scenes is difficult to meet by simply relying on high water reducing rate. Taking slump retention as an example, the large-scale application of ready-mixed concrete makes concrete challenging to transport long distances, pump long times, etc., from production to construction. In particular, in a large-volume concrete structure, ultra-long continuous casting and ultra-high-rise building, the fluidity of the concrete needs to be maintained for more than several hours. If the slump loss is too fast, the field cannot be pumped, the pipe is blocked and even is forced to be abandoned, not only is the resource waste and the construction period delayed caused, but also quality disputes and legal risks can be caused. Therefore, development of a polycarboxylic acid-based water reducing agent having excellent slump retaining ability has become an urgent need in the industry. Currently, the slump retaining agent is an additive capable of keeping concrete slump from losing rapidly, and the effect of keeping slump is achieved by slowing down hydration and condensation of cement under the action of special groups. In the prior art, due to large material quality difference, the problems of poor workability, easy hysteresis and bleeding and the like often occur due to fluctuation of materials of concrete operators in practical application. In addition, the existing product still has a key bottleneck, namely the solid content is generally in the range of 40% -50%, so that the economical efficiency and the industrial application of the product are severely restricted. Although the high solid content can improve the efficacy, the solution viscosity is too high, the load of a material conveying pump is increased, equipment loss is easy to cause, and the high-efficiency application of the product in large-scale engineering is restricted, for example, CN107721232A discloses a high-solid content slow-release polycarboxylate water reducer with the solid content of 55-65%, and CN105778014B also reports a high-solid content polycarboxylate water reducer with the solid content of 50-63.4%. However, the solid content of these prior art products is still at a moderate level, and the problem that high solid content necessarily leads to high viscosity cannot be effectively solved, and there is room for improvement in water locking and slurry stabilizing properties in concrete. In addition, there are drawbacks in that the preparation process is complicated and the slump loss with time is excessive, as described in CN1167739 a. Therefore, developing a polycarboxylic acid slump retaining agent with high solid content and low viscosity has become a key technical problem to be broken through in industry. Disclosure of Invention In order to solve the defects in the background art, the preparation method of the high-solid polycarboxylic acid slump retaining agent provided by the invention comprises the following steps: s1, under the inert atmosphere and ice water bath conditions, adding water, an organic solvent, tea polyphenol and inorganic alkali, uniformly stirring, heating, slowly dropwise adding a sulfonate monomer, and separating and purifying after the reaction is finished to obtain a tea polyphenol-based polybasic sulfonic acid solubilizer; s2, uniformly mixing and dissolving the polyether macromonomer M, the water-locking slurry-stabilizing small monomer and water, adding the prepared tea polyphenol-based polybasic sulfoacid solubilizer, uniformly mixing, dropwise adding the unsaturated small monomer, the unsaturated carboxylic ester, the initiator aqueous solution and the molecular weight regulator aqueous solution, and regulating the pH value of the system after the reaction is finished to obtain the high-solid-content polycarboxylic acid slump retaining agent. In step S1, the mass ratio of the tea polyphenol to the sulfonate monomer to the inorganic base to the organic solvent is 1 (1.8-5.0) (0.5-2.0) (5-10). In step S1, the sulfonate monomer is one or more of 1, 3-propane sultone, 1, 4-butane sultone and 2, 4-butane sultone, the inorganic base is potassium hydroxide or sodium hydroxide, and the organic solvent is tetrahydrofuran. In the step S2, the mass ratio of the polyether macromonomer M to the tea polyphenol based polybasic sulfoacid solubilizer to the unsaturated monomer to the water-locking slurry-stabilizing monomer to the unsaturated carboxylic ester is 200 (2-10): 2-15): 2-8): 10-35. Further, the water-locking and slurry-stabilizing small monomer i