Maleic rosin modified polycarboxylic acid high-efficiency water reducing agent and preparation method thereof
Through the esterification reaction of the Malay rosin modified polycarboxylic acid water reducing agent, the molecular size of its side chain is increased, and the problem of excessive adsorption of existing water reducing agents on the soil is solved, which significantly improves the mud resistance and the dispersion effect of cement particles, reduces production costs and improves the performance of concrete.
Patent Information
- Application Number
- CN202510254513.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-05
- Publication Date
- 2025-05-27
AI Technical Summary
The adsorption amount of existing polycarboxylic acid water reducing agent on soil increases, while the adsorption amount on cement particles decreases, affecting the dispersion of cement particles, leading to an increase in consumption of water reducing agents and an increase in production costs.
Malay rosin modified vinyl ether macromonomer is used through the esterification reaction to increase the molecular size of the side chain polyoxyethylene ether of the water reducing agent so that it cannot be inserted into the interlayer structure of the soil, thereby reducing the adsorption amount on the soil and increasing the adsorption amount on the cement.
It significantly improves the mud resistance of the water reducer, reduces the amount of water reducer, reduces the production cost of concrete, and improves the flowability and durability of concrete.
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Figure CN120040678A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of concrete admixtures, and particularly relates to a maleic rosin modified polycarboxylate superplasticizer and a preparation method thereof. Background Art
[0002] With the development of the construction industry, the requirements for concrete superplasticizers at home and abroad are getting higher and higher. In addition to maintaining the concrete slump unchanged for a relatively long time to extend the construction time, it is also necessary to reduce the sensitivity of the superplasticizer to different raw materials, so as to reduce the dosage and production cost. Polycarboxylate superplasticizer is a third-generation concrete superplasticizer, which has a good dispersion effect on cement particles, can improve the workability of concrete, reduce the unit water consumption, and enhance the concrete performance. At present, superplasticizer has become an essential external auxiliary material for concrete construction.
[0003] Polycarboxylate superplasticizer is synthesized by copolymerization of macromonomers containing polyoxyethylene ether segments and functional monomers such as acrylic acid. The functional groups such as carboxyl groups on its main chain are adsorbed on the surface of cement particles through electrostatic action, while the side-chain polyoxyethylene segments play the role of generating a hydration protective film and steric hindrance, so that the cement particles are dispersed due to electrostatic and steric repulsion. However, most of the sand and gravel used for mixing concrete are contaminated with soil, and its main components are montmorillonite, kaolin, etc. The structure of these soils is a layered crystal structure, and the interlayer spacing of the crystal is equivalent to the diameter of the polyoxyethylene segments of the polycarboxylate superplasticizer molecule. Therefore, the polyoxyethylene segments of the superplasticizer side chain are easily inserted into it, resulting in an increase in the adsorption amount of the superplasticizer on the soil and a decrease in the adsorption amount on the cement particles. This not only affects the dispersion of cement particles, but also increases the consumption of the superplasticizer. For sand and gravel with poor quality, which contain more soil and have a greater adsorption amount of the superplasticizer, the adsorption amount of the superplasticizer on the cement in the concrete is significantly reduced. To obtain concrete with similar workability, more superplasticizer must be added, which will undoubtedly increase the production cost of the concrete. Therefore, it is of great significance to develop a polycarboxylate superplasticizer with high efficiency, excellent anti-clay performance and low cost. Summary of the Invention
[0004] The object of the present invention is to provide a novel water reducing agent and its preparation method in view of the deficiencies of the prior art, specifically a maleic rosin modified polycarboxylate superplasticizer and its preparation method. Through an esterification reaction, the present invention uses the abundantly sourced natural renewable resource maleic rosin to modify vinyl ether macromonomers and further synthesize a superplasticizer, increasing the molecular size of the polyoxyethylene ether side chain of the water reducing agent, such that it cannot insert into the interlayer structure of the soil, thereby significantly reducing the adsorption amount of the water reducing agent on the soil, enhancing the anti-clay performance of the water reducing agent, and further increasing its adsorption on cement, significantly improving the dispersion performance of cement particles. The preparation method of the present invention has a simple process, is environmentally friendly and low-cost, and the prepared superplasticizer has excellent anti-clay performance and foaming performance, which is beneficial to improving the fluidity and durability of concrete.
[0005] The technical solution adopted by the present invention is as follows: A maleic rosin modified polycarboxylate superplasticizer is made from the following raw materials in parts by weight: Maleic rosin: 20 parts; Vinyl ether macromonomer: 100 - 300 parts; Maleic anhydride: 1 - 10 parts; Acrylic acid: 5 - 20 parts; Hydrogen peroxide: 1 - 5 parts; Vitamin C: 0.1 - 1.5 parts; Chain transfer agent: 0.5 - 2.5 parts; Deionized water: 300 - 400 parts.
[0006] Further, the vinyl ether macromonomer is one or a combination of more of ethylene glycol mono vinyl polyoxyethylene ether, diethylene glycol mono vinyl polyoxyethylene ether, and butylene glycol mono vinyl polyoxyethylene ether.
[0007] Further, the chain transfer agent is one or a combination of more of mercaptopropionic acid, mercaptoethanol, and mercaptoacetic acid.
[0008] For the above-mentioned maleic rosin modified polycarboxylate superplasticizer, a one-pot preparation method is adopted. First, the vinyl ether macromonomer is modified with maleic rosin, and then a polymerization reaction is carried out to obtain a polycarboxylate water reducing agent. The specific preparation method includes the following steps: (1) Take each raw material in parts by weight and set aside; add 20 parts of maleic rosin and 100 - 300 parts of vinyl ether macromonomer to a reaction kettle, introduce nitrogen to exhaust air, and under nitrogen protection, stir and react at 80 - 130 °C for 3 - 10 h to obtain an esterification modified product, and cool to room temperature; (2) Next, 1 - 10 parts of maleic anhydride and 100 - 134 parts of deionized water were added to the reaction system, and then mechanically stirred and slightly heated until all the reactants were dissolved. The temperature of the materials was controlled at 15°C, and then solution A (composed of 5 - 20 parts of acrylic acid, 1 - 5 parts of hydrogen peroxide, and 100 - 133 parts of deionized water) was slowly added to the flask within 30 min through a peristaltic pump; after the initiator solution A was added for 5 minutes, solution B (composed of 0.5 - 2.5 parts of chain transfer agent, 0.1 - 1.5 parts of vitamin C, and 100 - 133 parts of deionized water) was dropped into the reaction system within 25 min. (3) After the addition of solutions A and B was completed, the reaction system was continuously kept at a constant temperature for 2 h, and then neutralized with 30 wt% NaOH solution to a pH value of 6 - 8 to obtain the maleic rosin modified polycarboxylate superplasticizer.
[0009] The positive effects produced by the present invention are as follows: 1. For the maleic rosin modified polycarboxylate superplasticizer prepared by the present invention, due to the modification, the molecular size at the end of the polyoxyethylene ether side chain of the superplasticizer is increased, making it difficult to insert into the layer spacing of clay crystals and the micropores of sand and gravel, which can significantly reduce the adsorption amount of the superplasticizer on clay and sand and gravel, significantly improve the anti - mud performance of the superplasticizer, thereby reducing the dosage of the superplasticizer and saving the production cost of concrete. At the same time, it also enhances the adaptability of the polycarboxylate superplasticizer to different raw materials.
[0010] 2. Maleic rosin has the foaming effect of a surfactant, and a lot of tiny bubbles will be generated during the mixing process of concrete. Due to the ball - rolling effect, it can not only increase the fluidity of concrete, but also these tiny bubbles form micropores after the concrete solidifies, which can improve the durability of concrete and avoid the cracking of concrete caused by thermal expansion and contraction. Therefore, the superplasticizer synthesized from the macromonomer modified by maleic rosin is of great significance for improving the workability and durability of concrete.
[0011] 3. The present invention synthesizes the maleic rosin modified polycarboxylate superplasticizer by the one - pot method, which has the advantages of simple preparation process, environmental friendliness, and low cost, and does not produce any substances harmful to the environment. Moreover, the present invention uses the naturally renewable resource maleic rosin with rich sources as the modifier, which not only reduces the raw material cost but also improves the environmental friendliness of the polycarboxylate.
[0012] 4. The tests of the present invention show that: under the same conditions, compared with the superplasticizer prepared without maleic rosin modification, the anti - mud performance of the polycarboxylate superplasticizer prepared by the present invention using maleic rosin to modify vinyl ether - type macromonomers and then further prepared is significantly improved. The experimental results show that the anti - clay performance of the polycarboxylate superplasticizer prepared by the method of the present invention can be significantly and effectively improved by maleic rosin modification.
[0013] 5. The polycarboxylate superplasticizer prepared by the present invention introduces large-volume maleic rosin hydrophobic groups through grafting, changing the molecular structure of the polycarboxylate superplasticizer, enhancing the surface activity of the superplasticizer, increasing the molecular size at the end of the polyoxyethylene ether side chain, improving its dispersion and foaming properties, and significantly enhancing its anti-clay performance. It not only improves the problem of the decline in the workability of concrete caused by the clay content in sand and gravel, but also can improve its durability. The superplasticizer prepared by the method of the present invention has the advantages of high efficiency, excellent anti-clay performance, good foaming property, low dosage, high water reduction rate, good workability, and can significantly reduce the viscosity of the slurry, and is widely applicable to various concrete mixtures. The present invention provides new ideas and application potential for the development of superplasticizers with high efficiency, excellent anti-clay performance and environmental friendliness, and has good market prospects and application values. Description of the Drawings
[0014] Figure 1 is the infrared spectrogram of the maleic rosin modified polycarboxylate superplasticizer and ethylene glycol mono vinyl polyoxyethylene ether prepared by the method of the present invention. Figure 1 In the maleic rosin modified polycarboxylate superplasticizer, the stretching vibration peak of -OH is at 3430 cm -1 and the stretching vibration peak of -C=O in the carboxyl group is at 1728 cm -1 The stretching vibration peaks of C-O-C at 1108, 962 and 842 cm -1 are the characteristic peaks of polyoxyethylene ether. The stretching vibration peak of the C=C double bond at 1640 cm -1 disappears obviously, and the out-of-plane bending vibration peak of unsaturated C-H at 1058 cm -1 is weakened due to the strong characteristic peaks of polyoxyethylene ether. The results show the occurrence of the polymerization process and the existence of various characteristic functional groups such as carboxyl, methyl, and ether groups in the polymerization product.
[0015] Figure 2 is the GPC diagram of the maleic rosin modified polycarboxylate superplasticizer prepared by the method of the present invention. Its number average molecular weight is 5907 g / mol, the weight average molecular weight is 8074 g / mol, and the molecular weight distribution coefficient is 1.36. Detailed Embodiments Example 1
[0016] A preparation method of a maleic rosin modified polycarboxylate superplasticizer includes the following steps: (1) By weight parts, take 20 parts of maleic rosin, 100 parts of ethylene glycol mono vinyl polyoxyethylene ether, 1 part of maleic anhydride, 5 parts of acrylic acid, 1 part of hydrogen peroxide, 0.1 part of vitamin C, 0.5 part of mercaptoacetic acid, and 300 parts of deionized water for standby; add 20 parts of maleic rosin and 100 parts of ethylene glycol mono vinyl polyoxyethylene ether macromonomer into the reaction kettle, introduce nitrogen to exhaust air, and stir and react at 130 °C for 10 h under nitrogen protection to obtain an esterification modified product, and cool to room temperature.
[0017] (2) Then add 1 part of maleic anhydride and 100 parts of deionized water into the reaction system, then mechanically stir and slightly heat until the reaction is completely dissolved, control the material temperature at 15 °C, and then slowly add solution A (composed of 5 parts of acrylic acid, 1 part of hydrogen peroxide and 100 parts of deionized water) into the flask within 30 min through a peristaltic pump. After the initiator solution A is added dropwise for 5 minutes, then add solution B (composed of 0.5 part of mercaptoethanol, 0.1 part of vitamin C and 100 parts of deionized water) into the reaction system within 25 min.
[0018] (3) After the addition of solutions A and B is completed, keep the reaction system at a constant temperature for 2 h, and then neutralize it with 30 wt% NaOH solution to a pH value of 6 to obtain a maleic rosin modified polycarboxylate superplasticizer. Example 2
[0019] A preparation method of a maleic rosin modified polycarboxylate superplasticizer includes the following steps: (1) By weight parts, take 20 parts of maleic rosin, 100 parts of diethylene glycol mono vinyl polyoxyethylene ether, 1 part of maleic anhydride, 5 parts of acrylic acid, 1 part of hydrogen peroxide, 0.1 part of vitamin C, 0.5 part of mercaptoethanol, and 300 parts of deionized water for standby; add 20 parts of maleic rosin and 100 parts of diethylene glycol mono vinyl polyoxyethylene ether macromonomer into the reaction kettle, introduce nitrogen to exhaust air, and stir and react at 120 °C for 10 h under nitrogen protection to obtain an esterification modified product, and cool to room temperature.
[0020] (2) Then add 1 part of maleic anhydride and 100 parts of deionized water into the reaction system, then mechanically stir and slightly heat until the reaction is completely dissolved, control the material temperature at 15 °C, and then slowly add solution A (composed of 5 parts of acrylic acid, 1 part of hydrogen peroxide and 100 parts of deionized water) into the flask within 30 min through a peristaltic pump. After the initiator solution A is added dropwise for 5 minutes, then add solution B (composed of 0.5 part of mercaptoethanol, 0.1 part of vitamin C and 100 parts of deionized water) into the reaction system within 25 min.
[0021] After the addition of Solutions A and B is completed, the reaction system is continuously maintained at a constant temperature for 2 h, and then neutralized to a pH value of 6 with 30 wt% NaOH solution to obtain the maleic rosin modified polycarboxylate superplasticizer. Example 3
[0022] A preparation method of a maleic rosin modified polycarboxylate superplasticizer, comprising the following steps: (1) By weight, take 20 parts of maleic rosin, 200 parts of butanediol mono vinyl polyoxyethylene ether, 5 parts of maleic anhydride, 15 parts of acrylic acid, 3 parts of hydrogen peroxide, 1 part of vitamin C, 1.5 parts of mercaptopropionic acid, and 360 parts of deionized water, and set aside; Add 20 parts of maleic rosin and 200 parts of the macromolecular monomer of butanediol mono vinyl polyoxyethylene ether to the reaction kettle, introduce nitrogen to exhaust air, and stir and react at 110 °C for 7 h under nitrogen protection to obtain an esterification modified product, and cool to room temperature.
[0023] (2) Then add 5 parts of maleic anhydride and 120 parts of deionized water to the reaction system, then mechanically stir and slightly heat until the reaction is completely dissolved, control the material temperature at 15 °C, and then slowly add Solution A (composed of 15 parts of acrylic acid, 3 parts of hydrogen peroxide and 120 parts of deionized water) into the flask within 30 min through a peristaltic pump. After the initiator Solution A is added dropwise for 5 minutes, then add Solution B (composed of 1.5 parts of mercaptopropionic acid, 1 part of vitamin C and 120 parts of deionized water) into the reaction system dropwise within 25 min.
[0024] (3) After the addition of Solutions A and B is completed, the reaction system is continuously maintained at a constant temperature for 2 h, and then neutralized to a pH value of 7 with 30 wt% NaOH solution to obtain the maleic rosin modified polycarboxylate superplasticizer. Example 4
[0025] A preparation method of a maleic rosin modified polycarboxylate superplasticizer, comprising the following steps: (1) By weight, take 20 parts of maleic rosin, 200 parts of ethylene glycol mono vinyl polyoxyethylene ether, 5 parts of maleic anhydride, 15 parts of acrylic acid, 3 parts of hydrogen peroxide, 1 part of vitamin C, 1.5 parts of mercaptoacetic acid, and 360 parts of deionized water, and set aside; Add 20 parts of maleic rosin and 200 parts of the macromolecular monomer of ethylene glycol mono vinyl polyoxyethylene ether to the reaction kettle, introduce nitrogen to exhaust air, and stir and react at 100 °C for 7 h under nitrogen protection to obtain an esterification modified product, and cool to room temperature.
[0026] (2) Next, 5 parts of maleic anhydride and 120 parts of deionized water were added to the reaction system. Then, mechanical stirring was carried out and slightly heated until the reaction was completely dissolved. The temperature of the materials was controlled at 15 °C. Then, solution A (composed of 15 parts of acrylic acid, 3 parts of hydrogen peroxide, and 120 parts of deionized water) was slowly added to the flask within 30 min through a peristaltic pump. After the initiator solution A was added dropwise for 5 minutes, solution B (composed of 1.5 parts of mercaptoacetic acid, 1 part of vitamin C, and 120 parts of deionized water) was dropped into the reaction system within 25 min.
[0027] (3) After the addition of solutions A and B was completed, the reaction system was continuously reacted at a constant temperature for 2 h, and then neutralized to a pH value of 7 with 30 wt% NaOH solution to obtain the maleic rosin modified polycarboxylate superplasticizer. Example 5
[0028] A preparation method of a maleic rosin modified polycarboxylate superplasticizer includes the following steps: (1) By weight, 20 parts of maleic rosin, 300 parts of diethylene glycol mono vinyl polyoxyethylene ether, 10 parts of maleic anhydride, 20 parts of acrylic acid, 5 parts of hydrogen peroxide, 1.5 parts of vitamin C, 2.5 parts of mercaptoethanol, and 399 parts of deionized water were taken and reserved. 20 parts of maleic rosin and 300 parts of the macromolecular monomer of diethylene glycol mono vinyl polyoxyethylene ether were added to the reaction kettle, nitrogen was introduced to exhaust the air, and stirring reaction was carried out at 80 °C for 5 h under nitrogen protection to obtain an esterification modified product, which was cooled to room temperature.
[0029] (2) Next, 10 parts of maleic anhydride and 133 parts of deionized water were added to the reaction system. Then, mechanical stirring was carried out and slightly heated until the reaction was completely dissolved. The temperature of the materials was controlled at 15 °C. Then, solution A (composed of 20 parts of acrylic acid, 5 parts of hydrogen peroxide, and 133 parts of deionized water) was slowly added to the flask within 30 min through a peristaltic pump. After the initiator solution A was added dropwise for 5 minutes, solution B (composed of 2.5 parts of mercaptoethanol, 1.5 parts of vitamin C, and 133 parts of deionized water) was dropped into the reaction system within 25 min.
[0030] (3) After the addition of solutions A and B was completed, the reaction system was continuously reacted at a constant temperature for 2 h, and then neutralized to a pH value of 8 with 30 wt% NaOH solution to obtain the maleic rosin modified polycarboxylate superplasticizer. Example 6
[0031] A preparation method of a maleic rosin modified polycarboxylate superplasticizer includes the following steps: (1) By weight parts, take 20 parts of maleic rosin, 300 parts of butanediol mono vinyl polyoxyethylene ether, 10 parts of maleic anhydride, 20 parts of acrylic acid, 5 parts of hydrogen peroxide, 1.5 parts of vitamin C, 2.5 parts of mercaptopropionic acid, and 399 parts of deionized water for standby; Add 20 parts of maleic rosin and 300 parts of butanediol mono vinyl polyoxyethylene ether macromonomer into the reaction kettle, introduce nitrogen to exhaust the air, and stir and react at 80 °C for 3 h under nitrogen protection to obtain an esterification modified product, and cool to room temperature.
[0032] (2) Then add 10 parts of maleic anhydride and 133 parts of deionized water to the reaction system, then mechanically stir and slightly heat until the reaction is completely dissolved, control the material temperature at 15 °C, and then slowly add solution A (composed of 20 parts of acrylic acid, 5 parts of hydrogen peroxide and 133 parts of deionized water) into the flask within 30 min through a peristaltic pump. After the initiator solution A is added dropwise for 5 minutes, then add solution B (composed of 2.5 parts of mercaptopropionic acid, 1.5 parts of vitamin C and 133 parts of deionized water) into the reaction system within 25 min.
[0033] (3) After the addition of solution A and B is completed, keep the reaction system at a constant temperature for 2 h, and then neutralize it with 30 wt% NaOH solution to a pH value of 8 to obtain a maleic rosin modified polycarboxylate superplasticizer. Example 7
[0034] A preparation method of a maleic rosin modified polycarboxylate superplasticizer includes the following steps: (1) By weight parts, take 20 parts of maleic rosin, 200 parts of ethylene glycol mono vinyl polyoxyethylene ether, 10 parts of maleic anhydride, 20 parts of acrylic acid, 5 parts of hydrogen peroxide, 1.5 parts of vitamin C, 2.5 parts of mercaptoacetic acid, and 399 parts of deionized water for standby; Add 20 parts of maleic rosin and 200 parts of ethylene glycol mono vinyl polyoxyethylene ether macromonomer into the reaction kettle, introduce nitrogen to exhaust the air, and stir and react at 120 °C for 7 h under nitrogen protection to obtain an esterification modified product, and cool to room temperature.
[0035] (2) Then add 10 parts of maleic anhydride and 133 parts of deionized water to the reaction system, then mechanically stir and slightly heat until the reaction is completely dissolved, control the material temperature at 15 °C, and then slowly add solution A (composed of 20 parts of acrylic acid, 5 parts of hydrogen peroxide and 133 parts of deionized water) into the flask within 30 min through a peristaltic pump. After the initiator solution A is added dropwise for 5 minutes, then add solution B (composed of 2.5 parts of mercaptoacetic acid, 1.5 parts of vitamin C and 133 parts of deionized water) into the reaction system within 25 min.
[0036] After the addition of Solutions A and B is completed, the reaction system is continuously reacted at a constant temperature for 2 h, and then neutralized to a pH value of 8 with 30 wt% NaOH solution to obtain the maleic rosin modified polycarboxylate superplasticizer. Example 8
[0037] A preparation method of a maleic rosin modified polycarboxylate superplasticizer comprises the following steps: (1) By weight, take 20 parts of maleic rosin, 250 parts of ethylene glycol mono vinyl polyoxyethylene ether, 10 parts of maleic anhydride, 20 parts of acrylic acid, 5 parts of hydrogen peroxide, 1.5 parts of vitamin C, 2.5 parts of mercaptoacetic acid, and 399 parts of deionized water for standby; add 20 parts of maleic rosin and 250 parts of ethylene glycol mono vinyl polyoxyethylene ether macromonomer into a reaction kettle, introduce nitrogen to exhaust air, and stir and react at 120 °C for 7 h under nitrogen protection to obtain an esterification modified product, and cool to room temperature.
[0038] (2) Then add 10 parts of maleic anhydride and 133 parts of deionized water into the reaction system, then mechanically stir and slightly heat until the reaction is completely dissolved, control the material temperature at 15 °C, and then slowly add Solution A (composed of 20 parts of acrylic acid, 5 parts of hydrogen peroxide and 133 parts of deionized water) into the flask within 30 min through a peristaltic pump. After the initiator Solution A is added dropwise for 5 minutes, then add Solution B (composed of 2.5 parts of mercaptoacetic acid, 1.5 parts of vitamin C and 133 parts of deionized water) dropwise into the reaction system within 25 min.
[0039] (3) After the addition of Solutions A and B is completed, the reaction system is continuously reacted at a constant temperature for 2 h, and then neutralized to a pH value of 8 with 30 wt% NaOH solution to obtain the maleic rosin modified polycarboxylate superplasticizer. Example 9
[0040] A preparation method of a maleic rosin modified polycarboxylate superplasticizer comprises the following steps: (1) By weight, take 20 parts of maleic rosin, 300 parts of ethylene glycol mono vinyl polyoxyethylene ether, 10 parts of maleic anhydride, 20 parts of acrylic acid, 5 parts of hydrogen peroxide, 1.5 parts of vitamin C, 2.5 parts of mercaptoacetic acid, and 399 parts of deionized water for standby; add 20 parts of maleic rosin and 300 parts of ethylene glycol mono vinyl polyoxyethylene ether macromonomer into a reaction kettle, introduce nitrogen to exhaust air, and stir and react at 120 °C for 7 h under nitrogen protection to obtain an esterification modified product, and cool to room temperature.
[0041] (2) Next, 10 parts of maleic anhydride and 133 parts of deionized water were added to the reaction system, and then mechanically stirred and slightly heated until the reaction was completely dissolved. The material temperature was controlled at 15°C. Then, solution A (composed of 20 parts of acrylic acid, 5 parts of hydrogen peroxide, and 133 parts of deionized water) was slowly added to the flask within 30 min through a peristaltic pump. After the initiator solution A was added for 5 minutes, solution B (composed of 2.5 parts of mercaptoacetic acid, 1.5 parts of vitamin C, and 133 parts of deionized water) was dropped into the reaction system within 25 min.
[0042] (3) After the addition of solutions A and B was completed, the reaction system was continuously reacted at a constant temperature for 2 h, and then neutralized to a pH value of 8 with 30 wt% NaOH solution to obtain the maleic rosin modified polycarboxylate superplasticizer.
[0043] Comparative Example 1 A preparation method of a polycarboxylate superplasticizer includes the following steps: By weight, 300 parts of ethylene glycol mono vinyl polyoxyethylene ether, 10 parts of maleic anhydride, 20 parts of acrylic acid, 5 parts of hydrogen peroxide, 1.5 parts of vitamin C, 2.5 parts of mercaptoacetic acid, and 399 parts of deionized water were taken and reserved. 300 parts of the ethylene glycol mono vinyl polyoxyethylene ether macromonomer, 10 parts of maleic anhydride, and 133 parts of deionized water were added to the reaction kettle, and then mechanically stirred and slightly heated until the reaction was completely dissolved. The material temperature was controlled at 15°C. Then, solution A (composed of 20 parts of acrylic acid, 5 parts of hydrogen peroxide, and 133 parts of deionized water) was slowly added to the flask within 30 min through a peristaltic pump. After the initiator solution A was added for 5 minutes, solution B (composed of 2.5 parts of mercaptoacetic acid, 1.5 parts of vitamin C, and 133 parts of deionized water) was dropped into the reaction system within 25 min. After the addition of A and B was completed, the reaction system was continuously reacted at a constant temperature for 2 h, and then neutralized to a pH value of 8 with 30 wt% NaOH solution to obtain the polycarboxylate superplasticizer.
[0044] For the properties of the superplasticizers prepared in the above examples, according to GB / T8077 - 2023 "Test Methods for Uniformity of Concrete Admixtures", the fluidity performance of cement paste was measured, and the results are shown in Table 1.
[0045]
[0046] In Table 1, the modification ratio of maleic rosin in Example 1 and Example 2 is relatively large, and the fluidity of the neat paste is relatively small. However, after adding 1% montmorillonite and 5% kaolin, the decrease in fluidity of these samples is relatively small, showing good anti-clay performance. It should be noted that Comparative Example 1 is a water reducer synthesized using unmodified ethylene glycol mono vinyl polyoxyethylene macromonomer, and its synthesis method is the same as that of Example 9. The fluidity of the neat paste in Comparative Example 1 is 340 mm, which is significantly lower than 370 mm in Example 9. Moreover, after adding 1% montmorillonite and 5% kaolin, the decrease in fluidity of Comparative Example 1 is relatively significant. The initial fluidity of the neat paste and the fluidity of the neat paste after 1 hour in Example 9 are both significantly higher than those in Comparative Example 1. This result indicates that maleic rosin modified polycarboxylate superplasticizer has significant advantages in improving anti-clay performance.
Claims
1. A maleic rosin modified polycarboxylic acid high efficiency water reducing agent, characterized in that: Made from the following raw materials in parts by weight: 20 parts of Malay rosin; 100-300 parts of vinyl ether macromolecular monomer; 1-10 parts of maleic anhydride; 5-20 parts of acrylic acid; 1-5 parts of hydrogen peroxide; Vitamin C 0.1-1.5 parts; Chain transfer agent 0.5-2.5 parts; 300-400 parts of deionized water.
2. The maleated rosin modified polycarboxylic acid high efficiency water reducer according to claim 1, characterized in that: The vinyl ether macromonomer is one or more combinations of ethylene glycol monovinyl polyoxyethylene ether, diethylene glycol monovinyl polyoxyethylene ether, and butanediol monovinyl polyoxyethylene ether.
3. The maleated rosin modified polycarboxylic acid high efficiency water reducer according to claim 1, characterized in that: The chain transfer agent is one or more combinations of mercaptopropionic acid, mercaptoethanol and thioglycolic acid.
4. The method for preparing the maleated rosin modified polycarboxylic acid high efficiency water reducing agent according to any one of claims 1 to 3, characterized in that: The steps include: (1) Take each raw material by weight and set aside; add 20 parts of maleic rosin and 100-300 parts of vinyl ether macromolecular monomer into a reaction kettle, introduce nitrogen to exhaust the air, and stir and react at 80-130° C. for 3-10 hours under nitrogen protection to obtain an esterification modified product, and cool to room temperature; (2) Then, 1-10 parts of maleic anhydride and 100-134 parts of deionized water are added to the reaction system, and then mechanically stirred and slightly heated until all the reactants are dissolved, and the material temperature is controlled to be 15°C. Then, solution A consisting of 5-20 parts of acrylic acid, 1-5 parts of hydrogen peroxide and 100-133 parts of deionized water is slowly added to the flask over 30 minutes by a peristaltic pump; after the initiator solution A is dripped for 5 minutes, solution B consisting of 0.5-2.5 parts of chain transfer agent, 0.1-1.5 parts of vitamin C and 100-133 parts of deionized water is dripped into the reaction system over 25 minutes; (3) After the addition of solutions A and B was completed, the reaction system was allowed to continue to react at a constant temperature for 2 h, and then neutralized with a 30 wt % NaOH solution to a pH value of 6 to 8 to obtain a maleic rosin modified polycarboxylic acid high-efficiency water reducer.