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CN-122011295-A - Mud-resistant polycarboxylic acid high-performance water reducer and preparation method thereof

CN122011295ACN 122011295 ACN122011295 ACN 122011295ACN-122011295-A

Abstract

The invention belongs to the technical field of high molecular polymer water reducers, and particularly relates to an anti-mud type polycarboxylic acid high-performance water reducer and a preparation method thereof. The preparation method comprises the steps of adding D4H and a polyether macromonomer into an organic solvent according to a molar ratio of 1-1.5:1, mixing and dissolving, adding an organotin catalyst, heating and stirring for reaction, decompressing and steaming out the organic solvent and unreacted raw materials after the reaction is completed to obtain a mud-resistant functional monomer, adding a (methyl) hydroxyalkyl acrylate monomer, the mud-resistant functional monomer and a chain transfer agent into deionized water for mixing and dissolving, heating to 40-60 ℃, dripping a redox initiator and the (methyl) acrylic acid monomer for initiating copolymerization reaction, adding alkali for neutralization after the reaction is completed, and obtaining the mud-resistant polycarboxylic acid high-performance water reducer. The water reducer has obviously improved water reducing performance and mud resistance.

Inventors

  • HU JIE
  • CAO XUELIANG
  • ZHOU ZHAOQIONG
  • CHEN YONGJIANG

Assignees

  • 英德市竣冠新型材料有限公司

Dates

Publication Date
20260512
Application Date
20260317

Claims (10)

  1. 1. The preparation method of the anti-mud type polycarboxylic acid high-performance water reducer is characterized by comprising the following steps of: (1) Adding tetramethyl cyclotetrasiloxane and polyether macromonomer into an organic solvent according to the molar ratio of 1-1.5:1, mixing and dissolving, then adding an organotin catalyst, heating and stirring for reaction, and evaporating the organic solvent and unreacted raw materials under reduced pressure after the reaction is finished to obtain an anti-mud functional monomer; (2) Adding a (methyl) acrylic acid hydroxyalkyl ester monomer, an anti-mud functional monomer and a chain transfer agent into deionized water, mixing and dissolving, then heating to 40-60 ℃, dropwise adding a redox initiator and a (methyl) acrylic acid monomer to initiate copolymerization reaction, and adding alkali to neutralize after the reaction is completed to obtain the anti-mud type polycarboxylic acid high-performance water reducer.
  2. 2. The preparation method of the anti-mud type polycarboxylic acid high-performance water reducer is characterized in that in the steps (1) and (2), the polyether macromonomer is one or more of allyl polyoxyethylene ether, methallyl polyoxyethylene ether, isobutylene polyoxyethylene ether and isopentenyl polyoxyethylene ether, and the number average molecular weight of the polyether macromonomer is 1000-5000.
  3. 3. The method for preparing the anti-mud polycarboxylic acid high-performance water reducer according to claim 1, wherein the organic solvent in the step (1) is any one or a mixed solvent of a plurality of acetone, butanone, N-dimethylformamide and tetrahydrofuran.
  4. 4. The preparation method of the anti-mud polycarboxylic acid high-performance water reducer according to claim 1, wherein the organic tin catalyst in the step (1) is stannous iso-octoate, and the concentration of the organic tin catalyst in a reaction system is 0.1% -1%.
  5. 5. The method for preparing the anti-mud polycarboxylic acid high-performance water reducer according to claim 4, wherein the temperature of the heating and stirring reaction is 50-80 ℃ and the reaction time is 2-6 h.
  6. 6. The method for preparing the anti-mud polycarboxylic acid high-performance water reducer according to claim 1, wherein the hydroxyalkyl (meth) acrylate monomer in the step (2) is one or more of hydroxyethyl methacrylate, hydroxypropyl methacrylate and hydroxybutyl acrylate.
  7. 7. The method for preparing the anti-mud polycarboxylic acid high-performance water reducer according to claim 1, wherein the molar ratio of the hydroxyalkyl (meth) acrylate monomer to the anti-mud functional monomer to the (meth) acrylic acid monomer in the step (2) is 1-2:0.2-1:3-7.
  8. 8. The method for preparing the anti-mud type polycarboxylic acid high-performance water reducer according to claim 1, wherein the chain transfer agent in the step (2) is one of thioglycollic acid or mercaptopropionic acid.
  9. 9. The method of claim 1, wherein the redox initiator in the step (2) is a combination of at least one oxidant selected from the group consisting of hydrogen peroxide, sodium persulfate, potassium persulfate and ammonium persulfate and at least one reducing agent selected from the group consisting of ascorbic acid, sodium sulfite and sodium bisulfite.
  10. 10. The anti-mud type polycarboxylic acid high-performance water reducer is characterized by being prepared by the method of any one of claims 1-9.

Description

Mud-resistant polycarboxylic acid high-performance water reducer and preparation method thereof Technical Field The invention belongs to the technical field of high molecular polymer water reducers, and particularly relates to an anti-mud type polycarboxylic acid high-performance water reducer and a preparation method thereof. Background The polycarboxylic acid high-performance water reducer is an environment-friendly concrete additive with a comb-shaped structure, and the polycarboxylic acid high-performance water reducer is prepared by copolymerizing an acrylic acid monomer and a polyether macromonomer. The structural characteristics of the polycarboxylic acid high-performance water reducer enable the polycarboxylic acid high-performance water reducer to be firmly adsorbed on the surface of cement particles, and meanwhile, side chains extend into water to form a space barrier. The main action mechanism comprises 1, electrostatic repulsive force effect ‌, wherein anionic groups are adsorbed on the surfaces of positively charged cement particles to form an electric double layer, so that the particles have the same charge, repel each other, destroy a flocculation structure and release coating water. ‌ ‌ 2, ‌ steric hindrance ‌. After adsorption, long side chains stretch around the particles, and when the particles approach, the side chains overlap to generate repulsive forces, preventing aggregation. 3. The water-reducing adsorption film on the surface of the cement particles can form a layer of stable solvated water film with water molecules by the strong polar hydrophilic group in the water reducer, and the water film has good lubrication effect and can effectively reduce the sliding resistance among the cement particles. However, the polycarboxylic acid high-performance water reducer has insufficient mud resistance because of introducing polyether long side chains with strong hydrophilicity. The main reason is that the clay component contained in the concrete can form strong intercalation adsorption on the polyether long side chain with high flexibility and high degree of freedom, so that the adsorption effect of the water reducer on the clay is greater than the adsorption effect on cement particles, and the water reducing performance is reduced. Generally, the longer the molecular chain of the long side chain of the polyether is, the larger the steric hindrance effect of ‌ is, but the higher the flexibility and the degree of freedom are, the larger the intercalation adsorption effect is, and the poorer the mud resistance is. Along with the degradation of the concrete raw material sand and stone resources, the clay content is higher, and the requirements on the mud resistance of the polycarboxylic acid high-performance water reducer are increasingly urgent. Patent document with publication number CN 115197413A describes a polycarboxylic acid water reducer anti-mud functional monomer which is prepared by reacting polyethylene glycol, dihydric alcohol, a catalyst, a polymerization inhibitor and unsaturated carboxylic acid under certain technological conditions. The mud resistance of the water reducer can be effectively improved by adding the water reducer during the synthesis of the mother solution of the polycarboxylate superplasticizer. The mud resistance principle is that the mud resistance functional monomer contains a large amount of ether bonds, can be preferentially adsorbed between clay layers so that other water reducing agent molecules are adsorbed on the surfaces of cement particles, thereby playing the role of a sacrificial agent. However, the addition amount of the anti-mud sacrificial agent needs to be accurately calculated and adjusted according to the clay content in the concrete, so that the performance of the water reducer is ensured. The mud resistance of the polycarboxylic acid high-performance water reducer cannot be improved from the structural aspect of the polycarboxylic acid high-performance water reducer. In the patent document with publication number of CN 116333228A, we propose to use the combination of unsaturated polyoxyethylene ether grafted cyclosiloxane crosslinking agent and vinyl silane coupling agent comonomer to simultaneously improve the low-temperature crosslinking activity and the dispersion slump retaining effect of the polycarboxylic acid high-performance water reducer, but the mud resisting performance is not studied correspondingly, and the result shows that under the condition of only using unsaturated polyoxyethylene ether grafted cyclosiloxane crosslinking agent, the water reducing rate and the fluidity are reduced to a certain extent, which means that the introduction of a simple high-steric hindrance crosslinking monomer reduces the anchoring effect of water reducer molecules on cement particles and the dispersion capability is reduced. The adsorption amount of the polycarboxylic acid water reducer containing siloxane (silane coupling agent) on cement is larg