Anti-mud slump type polycarboxylate superplasticizer and preparation method thereof
By introducing ethylene glycol monovinyl ether polyoxyethylene ether, itaconic acid polyethylene glycol ester, and unsaturated sulfonic acid monomers to optimize the molecular structure of polycarboxylate superplasticizer, the problem of mud and powder adsorption on concrete in low-quality sand and gravel was solved, achieving good anti-mud and slump retention effects and improving concrete construction efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- KZJ NEW MATERIALS GROUP CO LTD
- Filing Date
- 2025-03-04
- Publication Date
- 2026-05-15
AI Technical Summary
Existing polycarboxylate superplasticizers have a weak adsorption capacity for mud and powder in low-quality sand and gravel, resulting in poor workability of concrete, severe bleeding or insufficient fluidity, increased production costs and insignificant effects.
Ethylene glycol monovinyl ether polyoxyethylene ether is used as the polyether monomer. Crosslinking monomer itaconic acid polyethylene glycol ester and rigid unsaturated monomer are introduced to form a crosslinked network structure. Unsaturated sulfonic acid monomer is also introduced to optimize the molecular structure to improve the anti-mud and anti-slump properties.
It significantly improves the anti-mud and slump-retention properties of polycarboxylate superplasticizers, reduces clay adsorption, enhances the compressive strength and construction efficiency of concrete, and reduces slump loss.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of concrete admixtures, specifically to an anti-slump polycarboxylate superplasticizer and its preparation method. Background Technology
[0002] In existing technologies, polycarboxylate superplasticizers are widely used in concrete engineering due to their advantages such as low dosage, high water reduction rate, adjustable function, flexible molecular design, and environmental friendliness. However, with the increasing demand for natural sand and gravel in concrete production, in order to reduce costs, ready-mix concrete companies often use recycled materials or low-quality natural sand and gravel. These materials generally have problems such as poor sand and gravel quality, high mud or powder content, resulting in quality problems in concrete such as poor workability, severe bleeding, or insufficient fluidity.
[0003] Conventional polycarboxylate superplasticizers have weak adsorption capacity for mud and powder in sand and gravel, requiring large-scale incorporation to achieve the desired effect, thus increasing production costs. Although there are technologies on the market for preparing anti-mud and slump-preserving polycarboxylate superplasticizers by designing molecular structures (such as the product synthesized from raw materials such as multi-arm polymer precursors as described in Chinese patent application 202010854758.7), these methods are complex, require high dosages, and do not significantly improve the overall performance of concrete, resulting in limited practical application effects.
[0004] Therefore, there is an urgent need to develop a polycarboxylate superplasticizer with good adaptability and excellent anti-slump properties to better solve the concrete construction problems caused by low-quality sand and gravel. Summary of the Invention
[0005] Therefore, it is necessary to provide a mud-resistant and slump-preserving polycarboxylate superplasticizer and its preparation method, in order to solve the concrete construction problems caused by low-quality sand and gravel.
[0006] To achieve the above objectives, the present invention provides a technical solution:
[0007] A slump-resistant polycarboxylate superplasticizer, wherein the raw materials for preparing the polycarboxylate superplasticizer, by weight, include:
[0008]
[0009]
[0010] In some embodiments, the crosslinking monomer includes polyethylene itaconic acid.
[0011] In some embodiments, the raw materials for preparing the itaconic acid polyethylene glycol ester, by weight, include:
[0012]
[0013] Specifically, itaconic acid, with the structural formula HOOC-CH2-C(COOH)-CH2-COOH, provides a carboxylic acid group as a reactant and undergoes an esterification reaction with the hydroxyl groups of polyethylene glycol PEG-200.
[0014] In some embodiments, the polymerization inhibitor includes hydroquinone.
[0015] In some embodiments, the catalyst comprises p-toluenesulfonic acid.
[0016] In some embodiments, the unsaturated sulfonic acid monomer includes at least one of 2-acrylamide-2-methylpropanesulfonic acid and sodium methacrylate.
[0017] In some embodiments, the rigid unsaturated monomer comprises (4-vinylphenyl)trimethoxysilane.
[0018] In some embodiments, the polyether macromonomer includes ethylene glycol monovinyl ether polyoxyethylene ether, wherein the molecular weight of the ethylene glycol monovinyl ether polyoxyethylene ether is 1000 to 3000.
[0019] In some embodiments, the unsaturated acid includes at least one of acrylic acid, methacrylic acid, and itaconic acid.
[0020] This invention also provides a method for preparing a mud-resistant and slump-preserving polycarboxylate superplasticizer, comprising the following steps:
[0021] The substrate is obtained by dissolving the polyether macromonomer in water to form a solution.
[0022] Add component A and component B dropwise to the base material, and after the addition is complete, maintain a constant temperature for reaction. After the reaction is completed, adjust the pH to 5-7 to obtain the anti-mud and anti-slump water-reducing agent.
[0023] Wherein, material A is a mixture of unsaturated acid, crosslinking monomer, unsaturated sulfonic acid monomer, rigid unsaturated monomer, and chain transfer agent dissolved in water;
[0024] Material B is a solution obtained by dissolving a reducing agent in water.
[0025] In some embodiments, the preparation steps of the itaconic acid polyethylene glycol ester are as follows:
[0026] Itaconic acid, hydroquinone, and p-toluenesulfonic acid are added to polyethylene glycol and reacted. Once the reaction is complete, itaconic acid polyethylene glycol ester is obtained.
[0027] In some of these embodiments, the reaction temperature is 80–100°C.
[0028] In some of these embodiments, the reaction time is 2 to 4 hours.
[0029] In some embodiments, the oxidant includes at least one of hydrogen peroxide, ammonium persulfate, sodium persulfate, and potassium persulfate.
[0030] In some embodiments, the raw materials for preparing the polycarboxylate superplasticizer include ferrous sulfate, with a mass fraction of 0.01 parts of ferrous sulfate.
[0031] In some embodiments, the unsaturated acid is acrylic acid.
[0032] In some embodiments, the chain transfer agent is at least one of mercaptoethanol, mercaptoacetic acid, and 2-mercaptopropionic acid.
[0033] In some embodiments, the reducing agent includes at least one of sodium formaldehyde sulfoxylate and L-ascorbic acid.
[0034] The beneficial effects of this invention are:
[0035] This invention uses ethylene glycol monovinyl ether polyoxyethylene ether as the polyether monomer, introduces the crosslinking monomer itaconic acid polyethylene glycol ester to form a crosslinked network molecular structure, and introduces rigid unsaturated monomers to avoid clay rubbing and adsorption, reduce clay surface adsorption sites, weaken the competitive adsorption effect of clay on polycarboxylate superplasticizer, and greatly improve the anti-mud and slump-preserving properties of polycarboxylate superplasticizer.
[0036] This invention introduces an unsaturated sulfonic acid monomer containing unsaturated sulfonic acid groups and methoxysilane side chains, which reduces the adsorption of water-reducing agents by soil. The carboxylate ions and polyether side chains in the molecular structure play the roles of adsorbing and dispersing cement, respectively. In the water-cement system, cement particles are better coated, improving mud resistance and low sensitivity, and exhibiting good mud resistance and slump retention.
[0037] This invention introduces side chains with micro-crosslinked structures into the polycarboxylate superplasticizer structure by adding itaconic acid polyethylene glycol ester crosslinking monomer, thereby enhancing the steric repulsion of the superplasticizer, resulting in good anti-mud properties and excellent slow-release effect, and demonstrating high adaptability to concrete with high mud content. Detailed Implementation
[0038] 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.
[0039] 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.
[0040] I. Preparation of cross-linked monomer itaconic acid polyethylene glycol ester
[0041] Add polyethylene glycol PEG-200 to a four-necked flask, start stirring, add itaconic acid, then add hydroquinone and p-toluenesulfonic acid in sequence, heat to 80-100℃, introduce nitrogen gas, and react at a constant temperature for 2-4 hours. After the esterification reaction is completed, cool down and take out the material. The brown liquid obtained is the itaconic acid polyethylene glycol ester solution.
[0042] The preparation process, formulation, and reaction conditions of itaconic acid polyethylene glycol ester are shown in Table 1.
[0043] Table 1 Process proportions and reaction conditions
[0044]
[0045] II. Preparation of Anti-slump Polycarboxylate Superplasticizer
[0046] Example 1
[0047] A solution of 100 parts of ethylene glycol monovinyl ether polyoxyethylene ether (molecular weight 3000) macromonomer dissolved in 100 parts of water was used as the base material. The temperature inside the reactor was controlled at 20°C. Then, 1 part of hydrogen peroxide and 7 parts of 1% ferrous sulfate were added to the reactor and stirred evenly. Next, A and B materials were added dropwise to the reactor at a uniform rate, and the addition was completed within 1 hour. After the addition was completed, the reaction was carried out at a constant temperature for 0.5 hours. 32% liquid alkali was added to neutralize and adjust the pH to 5-7. Water was added to adjust the solid content to 50% for the anti-slump polycarboxylate superplasticizer.
[0048] Component A is a mixture of 15 parts acrylic acid, 2 parts crosslinking monomer a, 3 parts 2-acrylamide-2-methylpropanesulfonic acid, 1 part (4-vinylphenyl)trimethoxysilane, and 1 part mercaptoethanol dissolved in 20 parts water. Component B is a solution of 0.5 parts sodium formaldehyde sulfoxylate dissolved in 30 parts water.
[0049] Example 2
[0050] A solution of 80 parts of ethylene glycol monovinyl ether polyoxyethylene ether (molecular weight 2000) macromonomer dissolved in 80 parts of water was used as the base material. The temperature inside the reactor was controlled at 20°C. Then, 1.5 parts of ammonium persulfate and 6 parts of 1% ferrous sulfate were added to the reactor and stirred evenly. Then, A and B materials were added dropwise to the reactor at a uniform rate, and the addition was completed within 1 hour. After the addition was completed, the reaction was carried out at a constant temperature for 0.5 hours. 32% liquid alkali was added to neutralize and adjust the pH to 5-7. Water was added to adjust the solid content to 50% for the anti-slump polycarboxylate superplasticizer.
[0051] Component A is a mixture of 13 parts methacrylic acid, 1 part crosslinking monomer c, 2 parts sodium methacrylate sulfonate, 1.5 parts (4-vinylphenyl)trimethoxysilane, and 1 part mercaptoacetic acid dissolved in 20 parts water. Component B is a solution of 0.5 parts L-ascorbic acid dissolved in 30 parts water.
[0052] Example 3
[0053] A solution of 80 parts of ethylene glycol monovinyl ether polyoxyethylene ether (molecular weight 1000) macromonomer dissolved in 80 parts of water was used as the base material. The temperature inside the reactor was controlled at 20°C. Then, 2 parts of sodium persulfate and 8 parts of 1% ferrous sulfate were added to the reactor and stirred evenly. Next, materials A and B were added dropwise to the reactor at a uniform rate, and the addition was completed within 1 hour. After the addition was completed, the reaction was carried out at a constant temperature for 0.5 hours. 32% liquid alkali was added to neutralize and adjust the pH to 5-7. Water was added to adjust the solid content to 50% for the anti-slump polycarboxylate superplasticizer.
[0054] Component A is a mixture of 10 parts itaconic acid, 1 part crosslinking monomer b, 2 parts 2-acrylamide-2-methylpropanesulfonic acid, 2 parts (4-vinylphenyl)trimethoxysilane, and 2 parts mercaptoethanol dissolved in 20 parts water. Component B is a solution of 2 parts L-ascorbic acid dissolved in 30 parts water.
[0055] Example 4
[0056] A solution of 90 parts of ethylene glycol monovinyl ether polyoxyethylene ether (molecular weight 3000) macromonomer dissolved in 90 parts of water was used as the base material. The temperature inside the reactor was controlled at 20°C. Then, 1 part of potassium persulfate and 5 parts of 1% ferrous sulfate were added to the reactor and stirred evenly. Then, A and B materials were added dropwise to the reactor at a uniform rate, and the addition was completed within 1 hour. After the addition was completed, the reaction was carried out at a constant temperature for 0.5 hours. 32% liquid alkali was added to neutralize and adjust the pH to 5-7. Water was added to adjust the solid content to 50% for the anti-slump polycarboxylate superplasticizer.
[0057] Component A is a mixture of 10 parts acrylic acid, 1 part crosslinking monomer d, 3 parts sodium methacrylate sulfonate, 2 parts (4-vinylphenyl)trimethoxysilane, and 2 parts 2-mercaptopropionic acid dissolved in 20 parts water. Component B is a solution of 2 parts L-ascorbic acid dissolved in 30 parts water.
[0058] Example 5
[0059] A solution of 100 parts of ethylene glycol monovinyl ether polyoxyethylene ether (molecular weight 2000) macromonomer dissolved in 100 parts of water was used as the base material. The temperature inside the reactor was controlled at 20°C. Then, 1 part of potassium persulfate and 10 parts of 1% ferrous sulfate were added to the reactor and stirred evenly. Next, A and B materials were added dropwise to the reactor at a uniform rate, and the addition was completed within 1 hour. After the addition was completed, the reaction was carried out at a constant temperature for 0.5 hours. 32% liquid alkali was added to neutralize and adjust the pH to 5-7. Water was added to adjust the solid content to 50% for the anti-slump polycarboxylate superplasticizer.
[0060] Component A is a mixture of 15 parts methacrylic acid, 2 parts crosslinking monomer a, 2 parts 2-acrylamide-2-methylpropanesulfonic acid, 1 part (4-vinylphenyl)trimethoxysilane, and 1.5 parts 2-mercaptopropionic acid dissolved in 20 parts water. Component B is a solution of 0.5 parts sodium formaldehyde sulfoxylate dissolved in 30 parts water.
[0061] Comparative Example 1
[0062] Based on Example 1, PEG-200 in crosslinking monomer a was replaced with MPEG-1200, while other conditions remained unchanged.
[0063] Comparative Example 2
[0064] Based on Example 1, itaconic acid in crosslinking monomer a was replaced with acrylic acid, while other conditions remained unchanged.
[0065] Comparative Example 3
[0066] Based on Example 1, crosslinking monomer a was replaced with methoxy polyethylene glycol methacrylate (MPEG-1200MAA), while other conditions remained unchanged.
[0067] Comparative Example 4
[0068] Based on Example 1, the polyether monomer was replaced with methacrylic polyethylene glycol ether (molecular weight 2400), while other conditions remained unchanged.
[0069] Comparative Example 5
[0070] Based on Example 1, the polyether monomer was replaced with isopentenyl polyethylene glycol ether (molecular weight 2400), while other conditions remained unchanged.
[0071] Comparative Example 6
[0072] Based on Example 1, (4-vinylphenyl)trimethoxysilane was not added, and other conditions remained unchanged.
[0073] The samples synthesized from Examples 1-5 and Comparative Examples 1-6 were prepared to a concentration of 10% using Jidong cement. The initial slump and spread, as well as the slump and spread over time, and the concrete state were measured according to GB 8076-2008 "Concrete Admixtures". The concrete mix proportion was: cement 260 kg / m³. 3 Fly ash (Grade II) 100kg / m³ 3 780kg / m³ of sand 3 Stone (5-10mm) 350kg / m 3 Stone (10-20mm) 640kg / m 3 Montmorillonite 50kg / m 3Water consumption: 170 kg / m³ 3 The expansion was controlled at 550±10mm, and the results are shown in Table 2.
[0074] Table 2. Concrete performance test results
[0075]
[0076] As can be seen from the test results in Table 2:
[0077] The anti-mud and slump-retaining polycarboxylate superplasticizers provided in Examples 1-5 were applied to concrete. Test results showed that the low dosage in Examples 1-5 resulted in minimal slump loss over time. This polycarboxylate superplasticizer improved the anti-mud and slump-retaining properties of concrete, reduced the impact of mud content in raw materials, and minimized slump loss during pumping. It also exhibited slightly higher compressive strength, lower shrinkage, good workability, good encapsulation, low viscosity, and fast flow rate. This polycarboxylate superplasticizer enhanced anti-mud performance, enabling pumped concrete construction and effectively improving concrete construction efficiency.
[0078] When the water-reducing agent provided in Comparative Example 1 was applied to concrete, the test results showed that compared with Examples 1-5, its spreadability loss over time increased and its flow rate was slow.
[0079] When the water-reducing agent provided in Comparative Example 2 was applied to concrete, the test results showed that compared with Examples 1-5, the workability of the concrete was generally poor, its spreadability decreased over time, and its flow rate was slow.
[0080] The water-reducing agent provided in Comparative Example 3 was applied to concrete. The test results showed that compared with Examples 1-5, the workability of the concrete was better, its spreadability decreased over time, and its flow rate was generally lower.
[0081] When the water-reducing agent provided in Comparative Example 4 was applied to concrete, the test results showed that compared with Examples 1-5, the workability of the concrete was average, the wrapping was poor, and the flow rate was fast.
[0082] The water-reducing agent provided in Comparative Example 5 was applied to concrete. The test results showed that compared with Examples 1-5, the concrete had better workability and better wrapping properties, but the flow rate was slower.
[0083] The water-reducing agent provided in Comparative Example 6 was applied to concrete. The test results showed that compared with Examples 1-5, the concrete had better workability, poorer wrapping properties, but slower flow rate.
[0084] Overall, the 28-day compressive strength ratio and 28-day shrinkage ratio of the concrete both meet the standard requirements.
[0085] 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. A slump-resistant polycarboxylate superplasticizer, characterized in that, The raw materials for preparing the polycarboxylate superplasticizer, by weight, include: 80-100 parts of polyether macromonomer; 1-2 parts of rigid unsaturated monomer; 1-2 parts of crosslinking monomer; 2-3 parts of unsaturated sulfonic acid monomer; 10-15 parts of unsaturated acid; Oxidizing agent 0.5-2 parts; Reducing agent 0.5–2 parts; and 1-2 parts of chain transfer agent; The crosslinking monomer includes polyethylene glycol itaconic acid; The unsaturated sulfonic acid monomer includes at least one of 2-acrylamide-2-methylpropanesulfonic acid and sodium methpropylene sulfonate; The rigid unsaturated monomer includes (4-vinylphenyl)trimethoxysilane; The polyether macromonomer includes ethylene glycol monovinyl ether polyoxyethylene ether.
2. The anti-slump polycarboxylate superplasticizer according to claim 1, characterized in that, The raw materials for preparing the itaconic acid polyethylene glycol ester, by weight, include: 80-100 parts of polyethylene glycol PEG-200; 100-150 parts of itaconic acid Polymerization inhibitor 0.001–0.002 parts; and Catalyst 0.01 to 0.05 parts.
3. The anti-slump polycarboxylate superplasticizer according to claim 1, characterized in that, The molecular weight of the ethylene glycol monovinyl ether polyoxyethylene ether is 1000-3000.
4. A method for preparing an anti-slump polycarboxylate superplasticizer as described in any one of claims 1 to 3, characterized in that, Including the following steps: The substrate is obtained by dissolving the polyether macromonomer in water to form a solution. Add component A and component B dropwise to the base material, and after the addition is complete, maintain a constant temperature for reaction. After the reaction is completed, adjust the pH to 5-7 to obtain the anti-mud and anti-slump water-reducing agent. Wherein, material A is a mixture of unsaturated acid, crosslinking monomer, unsaturated sulfonic acid monomer, rigid unsaturated monomer, and chain transfer agent dissolved in water; Material B is a solution obtained by dissolving a reducing agent in water.
5. The preparation method of the anti-slump polycarboxylate superplasticizer according to claim 4, characterized in that, The preparation steps of the itaconic acid polyethylene glycol ester are as follows: Itaconic acid, hydroquinone, and p-toluenesulfonic acid are added to polyethylene glycol and reacted. Once the reaction is complete, itaconic acid polyethylene glycol ester is obtained.
6. The preparation method of the anti-slump polycarboxylate superplasticizer according to claim 5, characterized in that, The reaction temperature is 80–100℃.
7. The preparation method of the anti-slump polycarboxylate superplasticizer according to claim 5, characterized in that, The reaction time is 2 to 4 hours.