Anti-slump water reducing agent and preparation method thereof

Abstract

This invention relates to an anti-mud-type water-reducing agent and its preparation method. By weight, the raw materials for preparing the anti-mud-type water-reducing agent include 200-300 parts of unsaturated polyether macromonomer; 10-20 parts of unsaturated acid; 20-40 parts of unsaturated ester; 5-10 parts of aromatic ring amino acid ester; 1-2 parts of reducing agent; 1-2 parts of oxidizing agent; 1-3 parts of chain transfer agent; 5-10 parts of neutralizing agent; and 100-200 parts of water. This invention introduces aromatic ring amino acid ester through a polymerization reaction. The aromatic ring amino acid ester has a benzene ring, amino group, and phosphate group structure. The cyclic amino acid ester combines with the unsaturated slump-retaining ester monomer to obtain the anti-mud-type water-reducing agent. The anti-mud-type water-reducing agent helps to weaken the adsorption of kaolin and montmorillonite, improving the performance of the anti-mud-type water-reducing agent under conditions of high mud content.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of concrete admixtures, in particular to an anti-mud water reducing agent and a preparation method thereof. BACKGROUND

[0002] Polycarboxylate superplasticizer has been rapidly developed due to its high water-reducing rate, good slump retention performance, strong structure designability, simple production process and green and environmentally friendly product.

[0003] Although polycarboxylate superplasticizer has remarkable advantages, there are still many aspects that need to be continuously improved and perfected, among which polycarboxylate superplasticizer is sensitive to the quality of concrete aggregate. Due to the consumption of a large amount of high-quality sand and gravel in the construction industry, machine-made sand and inferior sand are widely used in concrete, thereby increasing the mud content in the concrete. Since the anionic functional groups in polycarboxylate superplasticizer are prone to adsorption and intercalation with clay impurities in the raw materials of concrete, the slump loss of polycarboxylate superplasticizer is fast with the increase of the mud content in the concrete. SUMMARY

[0004] Therefore, it is necessary to provide an anti-mud water reducing agent and a preparation method thereof to solve the problem of fast slump loss of polycarboxylate superplasticizer caused by inferior aggregate.

[0005] To achieve the above-mentioned purpose, the present application provides a technical solution:

[0006] An anti-mud water reducing agent, the preparation raw materials of the anti-mud water reducing agent include, in terms of weight parts:

[0007]

[0008]

[0009] Preferably, the preparation step of the aromatic ring amino acid ester includes:

[0010] SOCl2, unsaturated phosphoric acid and ethanol are mixed, wherein the molar ratio of SOCl2: unsaturated phosphoric acid: aromatic ring amino acid-containing is 1:(1-2):1, to obtain a first mixture;

[0011] After the first mixture is cooled to-10℃, the aromatic ring amino acid-containing is added to the first mixture to obtain a second mixture;

[0012] The second mixture is heated to 40℃-60℃ and subjected to ultrasonic bath reflux reaction for 1h-2h to obtain the aromatic ring amino acid ester.

[0013] Preferably, the unsaturated phosphoric acid includes at least one of vinyl phosphoric acid, allyl phosphoric acid and cis-allyl phosphoric acid.

[0014] Preferably, the aromatic ring-containing amino acid comprises at least one of L-beta-p-hydroxyphenylalanine, 2-hydroxyphenylalanine and L-3,4-dihydroxyphenylalanine.

[0015] Preferably, the unsaturated ester comprises at least one of hydroxyethyl acrylate, hydroxypropyl acrylate, triethylene glycol diacrylate and triethylene glycol dimethacrylate.

[0016] Preferably, the unsaturated polyether comprises at least one of prenyl alcohol polyoxyethylene ether, ethylene glycol monovinyl polyethylene glycol ether and methyl allyl alcohol polyoxyethylene ether.

[0017] Preferably, the unsaturated acid comprises at least one of acrylic acid, methacrylic acid, fumaric acid and itaconic acid.

[0018] Preferably, the reducing agent comprises at least one of L-ascorbic acid, sodium sulfite, sodium hypophosphite and sodium thiosulfate.

[0019] Preferably, the oxidizing agent comprises at least one of hydrogen peroxide, ammonium persulfate and potassium persulfate.

[0020] Preferably, the neutralizing agent comprises at least one of a 32% sodium hydroxide solution by mass fraction and a 30% potassium hydroxide solution by mass fraction.

[0021] Preferably, the chain transfer agent comprises at least one of mercaptoacetic acid, sodium bisulfite, mercaptoethanol and mercaptopropionic acid.

[0022] A preparation method of the anti-mud water-reducing agent according to any one of the above, comprising the steps of:

[0023] Mixing the unsaturated polyether macromonomer, the oxidizing agent and water to obtain a base material;

[0024] Mixing the reducing agent, the chain transfer agent and water to obtain A liquid;

[0025] Mixing the unsaturated acid, the aromatic ring-containing amino acid ester, the unsaturated ester and water to obtain B liquid;

[0026] Adding the A liquid and the B liquid dropwise to the base material, the dropwise adding time being 2h-4h, and after the dropwise adding is completed, adding a neutralizing agent solution to adjust the pH to 6-8 to obtain the anti-mud water-reducing agent.

[0027] The beneficial effects of the present application are as follows:

[0028] The present application introduces the aromatic ring-containing amino acid ester through a polymerization reaction, the aromatic ring-containing amino acid ester has a benzene ring, an amino group and a phosphoric acid group structure, the benzene ring has a large steric hindrance ability and has better hydrophobic performance, and the phosphoric acid group and the amino group jointly hydrolyze Ca 2+Adsorption occurs, and in conjunction with slump-retaining esterified monomers, free water is prevented from entering the matrix particles, thereby increasing the amount of free water in the concrete and improving its fluidity. Cyclic amino acid esters combined with unsaturated slump-retaining esterified monomers yield anti-mud water-reducing agents. Anti-mud water-reducing agents are beneficial in weakening the adsorption of kaolin and montmorillonite, and improving the performance of anti-mud water-reducing agents under conditions of high mud content. Detailed Implementation

[0029] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0030] In the embodiments, unless otherwise specified, the experimental methods used are conventional methods, and the materials and reagents used are commercially available unless otherwise specified.

[0031] Example 1

[0032] Under ice bath stirring, 13 mL (11 mmol) of distilled SOCl2 was added to 15 mmol of allyl phosphoric acid and 10 mL of ethanol solution to obtain the first mixture;

[0033] The first mixture was cooled to -10°C, nitrogen gas was introduced, and then 1.972 g (10 mmol) of L-3,4-dihydroxyphenylalanine was added to the reaction mixture. The mixture was heated to 50°C and refluxed in an ultrasonic bath for 1.5 h. After the reaction was completed, the reaction solvent was removed, and the reaction product was purified by recrystallization from methanol:dry ether (1:2) to obtain the aromatic ring amino acid ester.

[0034] Accurately weigh 200 parts of ethylene glycol monovinyl polyethylene glycol ether, 150 parts of water, and 2 parts of hydrogen peroxide, place them in a four-necked reaction flask, install a stirrer and thermometer, and stir the mixture solution evenly to obtain the base material;

[0035] Prepare solution A: Mix 0.5 parts L-ascorbic acid, 1 part mercaptoacetic acid, and 50 parts deionized water to obtain solution A;

[0036] Prepare solution B by mixing 10 parts acrylic acid, 3 parts aromatic ring-containing amino acid ester, 30 parts hydroxyethyl acrylate, and 10 parts deionized water.

[0037] Start the stirrer and simultaneously add solution A and solution B dropwise to the substrate at a constant temperature for 2 hours. After the addition is complete, wait for the reaction solution to cool to room temperature, then add an appropriate amount of 32% sodium hydroxide solution to adjust the pH to 7, thus obtaining the 50% concentration anti-mud water-reducing agent.

[0038] Example 2

[0039] Distilled SOCl213 mL (11 mmol) was added to a solution of 15 mmol allyl phosphonic acid and 10 mL ethanol under ice-bath stirring to obtain a first mixture;

[0040] The first mixture was cooled to -10 DEG C, nitrogen was bubbled through, and L-beta-p-hydroxyphenylalanine 1.81 g (10 mmol) was added to the reaction mixture, which was heated to 50 DEG C and refluxed in an ultrasonic bath for 1.5 h. The reaction was completed, and the reaction product was purified to obtain the aromatic ring amino acid ester.

[0041] Accurately weighed 200 parts of isopentenyl alcohol polyoxyethylene ether, 150 parts of water, and 2 parts of hydrogen peroxide were placed in a four-necked reaction flask, a stirrer and a thermometer were installed, and the mixture solution was stirred uniformly to obtain a base material.

[0042] A solution was prepared by mixing 0.5 parts of L-ascorbic acid, 1 part of mercaptoacetic acid, and 50 parts of deionized water.

[0043] A solution was prepared by mixing 10 parts of acrylic acid, 3 parts of the aromatic ring amino acid ester, 30 parts of hydroxyethyl acrylate, and 10 parts of deionized water.

[0044] The stirrer was started, and the A solution and the B solution were simultaneously added to the base material at a constant temperature, and the dropping time was 3 h. After the addition was completed, the reaction solution was cooled to room temperature, and an appropriate amount of 32% sodium hydroxide solution was added to adjust the pH to 7, thereby obtaining the 50% mass concentration of the anti-mud water reducing agent.

[0045] Example 3

[0046] Distilled SOCl213 mL (11 mmol) was added to a solution of 15 mmol allyl phosphonic acid and 10 mL ethanol under ice-bath stirring to obtain a first mixture;

[0047] The first mixture was cooled to -10 DEG C, nitrogen was bubbled through, and 2-hydroxyphenylalanine 1.81 g (10 mmol) was added to the reaction mixture, which was heated to 50 DEG C and refluxed in an ultrasonic bath for 1.5 h. The reaction was completed, and the reaction product was purified to obtain the aromatic ring amino acid ester.

[0048] Accurately weighed 200 parts of isopentenyl alcohol polyoxyethylene ether, 150 parts of water, and 2 parts of hydrogen peroxide were placed in a four-necked reaction flask, a stirrer and a thermometer were installed, and the mixture solution was stirred uniformly to obtain a base material.

[0049] A solution was prepared by mixing 0.5 parts of L-ascorbic acid, 1 part of mercaptoacetic acid, and 50 parts of deionized water.

[0050] Configuration B liquid: 10 parts of acrylic acid, 3 parts of amino acid ester containing aromatic ring, 30 parts of hydroxyethyl acrylate, 10 parts of deionized water are mixed to obtain B liquid;

[0051] Start the stirrer, and add A liquid and B liquid into the bottom material at constant temperature at the same time. The dropping time is 4 h. After the dropping is completed, after the reaction solution is cooled to room temperature, an appropriate amount of 32% sodium hydroxide solution is added to adjust the pH to 7, to obtain the 50% mass concentration of the anti-mud water reducing agent.

[0052] Comparative Example 1

[0053] Accurately take 200 parts of isopentenyl alcohol polyoxyethylene ether, 150 parts of water, and 2 parts of hydrogen peroxide, and put them into a four-necked reaction flask. Install the stirrer, thermometer, and mix the solution uniformly to obtain the bottom material;

[0054] Configuration A liquid: 0.5 parts of L-ascorbic acid, 1 part of mercaptoacetic acid, and 50 parts of deionized water are mixed to obtain A liquid;

[0055] Configuration B liquid: 10 parts of acrylic acid, 30 parts of hydroxyethyl acrylate, and 10 parts of deionized water are mixed to obtain B liquid;

[0056] Start the stirrer, and add A liquid and B liquid into the bottom material at constant temperature at the same time. The dropping time is 2 h. After the dropping is completed, after the reaction solution is cooled to room temperature, an appropriate amount of 32% sodium hydroxide solution is added to adjust the pH to 7, to obtain the 50% mass concentration of the water reducing agent.

[0057] Comparative Example 2

[0058] Accurately take 200 parts of isopentenyl alcohol polyoxyethylene ether, 150 parts of water, and 2 parts of hydrogen peroxide, and put them into a four-necked reaction flask. Install the stirrer, thermometer, and mix the solution uniformly to obtain the bottom material

[0059] Configuration A liquid: 0.5 parts of L-ascorbic acid, 1 part of mercaptoacetic acid, and 50 parts of deionized water are mixed to obtain A liquid;

[0060] Configuration B liquid: 10 parts of acrylic acid, 30 parts of hydroxyethyl acrylate, and 10 parts of deionized water are mixed to obtain B liquid;

[0061] Start the stirrer, and add A liquid and B liquid into the bottom material at constant temperature at the same time. The dropping time is 2 h. After the dropping is completed, after the reaction solution is cooled to room temperature, an appropriate amount of 32% sodium hydroxide solution is added to adjust the pH to 7, to obtain the 50% mass concentration of the water reducing agent.

[0062] Concrete test:

[0063] The slump of the concrete was tested using Xiangtan Zhongcai P.O42.5 cement. The concrete mix design for the test was based on JGJ-55 "Specification for Mix Design of Ordinary Concrete". The concrete mix proportions are shown in Table 1.

[0064] The concrete performance tests were conducted in accordance with GB / T50080-2016 "Test Methods for Performance of Ordinary Concrete Mixtures" and GB / T50081-2019 "Test Methods for Mechanical Properties of Ordinary Concrete". Test data are shown in Table 2.

[0065] Table 1 Concrete mix proportions / m 3

[0066] Strength class Cement / kg Machine sand / kg Macadam (10-20 mm) / kg Water / kg C35 380 965 890 160

[0067] Table 2 Concrete Test Results

[0068]

[0069] As shown in Table 2, under the same slump reduction ratio of the water-reducing agent and without the addition of montmorillonite, the concrete loss after 1 hour was greater in Comparative Examples 1-2 and the commercially available water-reducing agent compared to Examples 1-3. When the montmorillonite content was increased to 5%, the slump retention performance of the concrete in Comparative Examples 1-2 and the commercially available water-reducing agent was significantly reduced compared to Examples 1-3. However, the slump retention performance of the anti-mud polycarboxylate water-reducing agent provided by this patent was not significantly different from that without the addition of montmorillonite. This indicates that the high slump retention polycarboxylate water-reducing agent of this invention has good slump retention and anti-mud properties, and is significantly better than commercially available water-reducing agents.

[0070] Phosphate groups hydrolyze under alkaline conditions and, together with amino groups, contribute to the formation of calcium in concrete. 2+ It adsorbs and works together with the slump-retaining esterified monomer to prevent free water from entering the matrix particles, thereby increasing the amount of free water in the concrete, improving fluidity, and thus enhancing the anti-slump and slump-retaining effect of polycarboxylate superplasticizer; moreover, it contains aromatic cyclic amino acids, which have a lower cost and can reduce environmental pollution.

[0071] It should be noted that the specific parameters or reagents in the above embodiments are specific or preferred embodiments under the concept of the present invention, and not limitations thereof; those skilled in the art can make adaptive adjustments within the concept and protection scope of the present invention.

Claims

1. An anti-slump water reducing agent, characterized by, The raw materials for preparing the anti-mud water reducing agent include, in parts by weight: an unsaturated polyether macromonomer 200-300 parts; an unsaturated acid 10-20 parts; an unsaturated ester 20-40 parts; an aromatic ring amino acid ester 5-10 parts; a reducing agent 1-2 parts; an oxidizing agent 1-2 parts; a chain transfer agent 1-3 parts; a neutralizing agent 5-10 parts; and water 100-200 parts. The unsaturated polyether macromonomer includes at least one of iso-pentenyl alcohol polyoxyethylene ether, ethylene glycol monovinyl polyethylene glycol ether, and methyl allyl alcohol polyoxyethylene ether. or ; In the formula, R1 is C 1-8 The unsaturated hydrocarbon group; R2 is at least one of -H and -OH; The unsaturated acid includes at least one of acrylic acid, methacrylic acid, fumaric acid, and itaconic acid. The unsaturated ester includes at least one of hydroxyethyl acrylate, hydroxypropyl acrylate, triethylene glycol diacrylate, and triethylene glycol dimethacrylate. The preparation steps of the aromatic ring amino acid ester include:

2. The anti-slump water reducing agent according to claim 1, characterized in that, mixing SOCl2, an unsaturated phosphoric acid, and ethanol to obtain a first mixture; after the first mixture is cooled to -15℃-0℃, adding an aromatic ring amino acid-containing acid to the first mixture to obtain a second mixture; heating the second mixture to 40℃-60℃ and performing ultrasonic bath reflux reaction for 1h-2h to obtain the aromatic ring amino acid ester. The unsaturated phosphoric acid includes at least one of vinyl phosphoric acid and allyl phosphoric acid.

3. The anti-slump water reducing agent according to claim 2, characterized in that, The aromatic ring amino acid-containing acid includes at least one of L-β-p-hydroxyphenylalanine, 2-hydroxyphenylalanine, and L-3,4-dihydroxyphenylalanine.

4. The anti-slump water reducing agent according to claim 2, wherein The reducing agent includes at least one of L-ascorbic acid, sodium sulfite, sodium hypophosphite, and sodium thiosulfate.

5. The anti-slump water reducing agent according to claim 1, wherein The oxidizing agent includes at least one of hydrogen peroxide, ammonium persulfate, and potassium persulfate.

6. The anti-slump water reducing agent according to claim 1, wherein The method includes the steps of:

7. A method for producing the anti-slump water reducing agent according to any one of claims 1 to 6, characterized by, mixing the unsaturated polyether macromonomer, the oxidizing agent, and water to obtain a base material; mixing the reducing agent, the chain transfer agent, and water to obtain A liquid; mixing the unsaturated acid, the aromatic ring amino acid ester, the unsaturated ester, and water to obtain B liquid; adding the A liquid and the B liquid dropwise to the base material, the dropwise adding time being 2h-4h, and after the dropwise adding is completed, adding a neutralizing agent solution to adjust the pH to 6-8 to obtain the anti-mud water reducing agent. ​

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