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An anti-cracking and shrinkage-reducing polycarboxylate water reducer and its preparation method

A technology of water reducing agent and polycarboxylic acid, which is applied in the field of anti-cracking and shrinkage polycarboxylate water reducing agent and its preparation, which can solve the problem of reducing the surface tension of the solution inside the cement slurry void, reducing the feasibility of industrial production, and lacking market competitiveness and other problems, to achieve excellent dispersion and retention effect, excellent crack resistance and shrinkage reduction performance, and safe and reliable preparation process

Active Publication Date: 2022-06-17
JIANGSU CHINA RAILWAY ARIT NEW MATEIRALS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Represented by Japan and the United States, some shrinkage reducers such as alcohols, ethers, and alcohol amines were reported in the early stage. Such shrinkage reducers have no water-reducing effect, and the required dosage is high, and they will also have side effects of reduced strength in the later stage. , which limits their use
For domestic research, patent CN103724567A discloses a shrinkage-reducing polycarboxylate water reducer and its preparation method. The preparation method is free radical polymerization after esterification. surface tension, but the esterification reaction used in it needs to be carried out at a high temperature for a long time, which also greatly reduces the feasibility of industrial production; A shrinkage-reducing water-reducer prepared by free-radical polymerization of polyoxyethylene / polyoxypropylene polydimethylsiloxane maleate and a shrinkage-reducing water-reducer and a synthetic method thereof, and the dispersion of the shrinkage-reducing water-reducer to concrete The impact on the slump retention performance is small, but the 28-day shrinkage rate is smaller than the relative benchmark, which lacks market competitiveness

Method used

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  • An anti-cracking and shrinkage-reducing polycarboxylate water reducer and its preparation method
  • An anti-cracking and shrinkage-reducing polycarboxylate water reducer and its preparation method
  • An anti-cracking and shrinkage-reducing polycarboxylate water reducer and its preparation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] 1) Preparation of prepolymerized product of anti-cracking and shrinkage-reducing superplasticizer: 1 mol of gallic acid and 4 mol of acetic anhydride were stirred and reacted at 50° C. for 3 h under the catalytic condition of concentrated sulfuric acid (0.2 mL), washed with water, and then reacted with propylene chloride at room temperature. Reaction for 24h to obtain gallic acid derivative unsaturated small monomer; the obtained small monomer (0.3mol), acrylic acid (3mol) in 50mL methanol with ammonium persulfate (0.1mol), sodium bisulfite (0.1mol) and 2-mercaptopropionic acid (0.08mol) was used together, and the prepolymerized product was obtained by carrying out free radical polymerization at 20°C for 4 hours;

[0035] 2) Add sodium hydroxide to the obtained prepolymerized product to make the solution pH 7-8, remove the protective group and then evaporate the solvent; continue to add the terminal halogen group modified polyether (1 mol, M w =1000g / mol) of 120mL aceto...

Embodiment 2

[0040] 1) Preparation of prepolymerized product of anti-cracking and shrinkage-reducing superplasticizer: 1 mol of gallic acid and 4 mol of acetic anhydride were stirred and reacted at 50° C. for 3 h under the catalytic condition of concentrated sulfuric acid (0.2 mL), washed with water, and then reacted with propene bromide at room temperature. Reaction for 24h to obtain gallic acid derivative unsaturated small monomer; the obtained small monomer (0.3mol), methacrylic acid (3.5mol) in 50mL acetone with hydrogen peroxide (0.15mol), sodium sulfite (0.08mol) and 3- Combined with mercaptopropionic acid (0.07mol), the prepolymerized product was obtained by performing radical polymerization at 30°C for 3.5 hours;

[0041] 2) adding potassium hydroxide to the obtained prepolymerized product to make the pH of the solution 7-8, removing the protective group and then evaporating to remove the solvent; continue to add the terminal halogen group modified polyether (1 mol, M w =800g / mol) ...

Embodiment 3

[0046]1) Preparation of prepolymerized product of anti-cracking and shrinkage-reducing superplasticizer: 1 mol of gallic acid and 4 mol of acetic anhydride were stirred and reacted at 50° C. for 3 h under the catalytic condition of concentrated sulfuric acid (0.2 mL), washed with water, and then reacted with propylene chloride at room temperature. Reaction for 24h to obtain gallic acid derivative unsaturated small monomer; the obtained small monomer (0.3mol), acrylamide (4mol) in 50mL ethanol with potassium persulfate (0.1mol), sodium metabisulfite (0.12mol) and 2 - Combined with mercaptopropionic acid (0.08mol), the prepolymerized product was obtained by performing free radical polymerization at 30°C for 4.5 hours;

[0047] 2) adding triethylamine to the obtained prepolymerized product to make the solution pH 7-8, and then evaporating to remove the solvent after removing the protective group; continue to add terminal halogen group modified polyether (1 mol, M w =3500g / mol) of...

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Abstract

The invention discloses an anti-cracking and shrinkage-reducing polycarboxylate water reducer and a preparation method thereof. Its weight-average molecular weight (M w ) is 10000~100000, and the structural formula is that the preparation method of the present invention is: (1) use gallic acid as raw material to introduce unsaturated double bond structure on the structure to prepare gallic acid derivative unsaturated small monomer, and then combine it with carbonyl-containing unsaturated monomer Saturated acid and its derivative monomers are subjected to free radical copolymerization to obtain a water reducer prepolymerization product; (2) Introduce a hydrophilic polyether side chain on the gallic acid derivative of the prepolymerization product to prepare a shrinkage reduction type with excellent performance Polycarboxylate superplasticizer. The anti-cracking and shrinkage-reducing polycarboxylate water-reducer prepared by the present invention has good stability and is suitable for storage under various extreme weather conditions; it has good dispersion effect in concrete, excellent shrinkage reduction effect, and is effective against cracking caused by various types of shrinkage. Very noticeable control and mitigation.

Description

technical field [0001] The invention relates to the field of polycarboxylate water-reducing agent for concrete, in particular to a crack-resisting shrinkage-reducing type polycarboxylate water-reducing agent and a preparation method thereof. Background technique [0002] Polycarboxylate superplasticizers have been widely used in railways, bridges and houses and other projects. In these infrastructures, the market has higher and higher requirements for additives. However, due to unavoidable factors, concrete is prone to cracking during early hardening and later use, which affects its durability. At present, a series of protective measures have also appeared on the market to deal with the cracking of concrete, such as improving the composition of glue materials, mixing expansion agents, mixing synthetic fibers, and formulating specific curing techniques for specific environments. However, from a comprehensive point of view, adding concrete shrinkage reducer is the simplest an...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08G81/02C04B24/32C04B103/30
CPCC08G81/025C04B24/32C04B2103/302
Inventor 卢通钱珊珊王学川赵旭彭荩影屈浩杰于鹏程郑春扬
Owner JIANGSU CHINA RAILWAY ARIT NEW MATEIRALS CO LTD
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