Refractory material dispersing agent and preparation method thereof

Abstract

The invention relates to a refractory material dispersing agent and a preparation method thereof in the technical field of refractory material additives, the refractory material dispersing agent is a copolymer with a comb structure, the copolymer comprises a styrene-maleic anhydride copolymer main chain, a polyethylene glycol side chain grafted on the styrene-maleic anhydride copolymer main chain through an ester bond, and a phosphate group; the polyethylene glycol side chain comprises short-chain polyethylene glycol with the molecular weight of 400-600 and long-chain polyethylene glycol with the molecular weight of 800-1200. According to the present invention, the asymmetric compound polyethylene glycol side chain with the specific molecular weight range is adopted, and the esterification grafting degree is controlled to be 50-85%, such that the precise function division is achieved, the excellent initial wetting and dispersing force can be provided so as to ensure the excellent construction fluidity of the slurry, and the re-aggregation and the re-sedimentation of the particles under the standing or shearing can be effectively prevented so as to achieve the good water resistance and water resistance; therefore, the technical problem that high initial fluidity, long-term anti-settling property and plasticity retaining property are difficult to consider in the traditional dispersant is fundamentally solved.

Description

Technical Field

[0001] This invention relates to the field of refractory material additives, and in particular to a refractory material dispersant and its preparation method. Background Technology

[0002] Refractory materials are widely used in high-temperature industries such as metallurgy, building materials, and chemicals. The performance and lifespan of these products largely depend on the uniformity, stability, and workability of the slurry during production. Dispersants, as key additives in refractory slurries, effectively prevent particle agglomeration by adsorbing onto the particle surface and generating electrostatic repulsion or steric hindrance effects, thus ensuring that the slurry system has good rheological properties.

[0003] Currently, the dispersants widely used in the refractory materials industry are mainly sodium tripolyphosphate, sodium hexametaphosphate, and naphthalene sulfonate formaldehyde condensate, etc. While these dispersants meet basic application requirements to a certain extent, their molecular structure and properties still have significant limitations, mainly in the following aspects: First, the dispersion efficiency and stability are insufficient. The aforementioned dispersants have relatively poor hydrophilicity, resulting in limited dispersion efficiency in refractory slurries. To achieve the required workability, a high water content is often required, which in turn reduces the solid content of the slurry, affecting the density of the formed green body and the strength of the final product.

[0004] Secondly, its fluidity retention is relatively poor, and it is easily damaged under long-term shearing or static conditions, resulting in obvious sedimentation and stratification of the slurry and premature thickening, which affects the construction quality.

[0005] Furthermore, existing technologies have also attempted to modify polyethers by grafting styrene-maleic anhydride copolymers with polyethers (e.g., a high-performance water-based polymeric dispersant for inks and its preparation method, published in CN120082043A). However, these technologies often employ subsequent amidation / imide modification with substances such as polyetheramines, resulting in relatively lengthy synthetic routes. Moreover, they fail to fundamentally address the issues of side-chain structure selection and optimization, and the resulting synergistic improvement in dispersion and thermal stability.

[0006] Therefore, the present invention provides a refractory material dispersant and its preparation method. Summary of the Invention

[0007] To overcome the shortcomings of the prior art, the present invention discloses a refractory material dispersant and its preparation method.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A refractory material dispersant is a comb-shaped copolymer comprising a styrene-maleic anhydride copolymer backbone, polyethylene glycol side chains grafted onto the styrene-maleic anhydride copolymer backbone via ester bonds, and phosphate groups; wherein the phosphate groups are introduced into the copolymer by chemical bonding, either by bonding to the ends of the polyethylene glycol side chains or by directly forming part of the styrene-maleic anhydride copolymer backbone as structural units; The polyethylene glycol side chains include short-chain polyethylene glycol with a molecular weight of 400-600 and long-chain polyethylene glycol with a molecular weight of 800-1200.

[0009] Furthermore, the degree of esterification grafting of the polyethylene glycol side chains is 50% to 85%.

[0010] Furthermore, the molar ratio of the short-chain polyethylene glycol to the long-chain polyethylene glycol is 1:0.5 to 1:2.

[0011] Furthermore, in the styrene-maleic anhydride copolymer backbone, the molar ratio of styrene structural units to maleic anhydride structural units is 1:0.8 to 1:1.2.

[0012] Furthermore, when the phosphate group is introduced in a manner that is bonded to the end of the polyethylene glycol side chain, it is formed by the reaction of the hydroxyl group at the end of the polyethylene glycol side chain with a phosphorylating agent.

[0013] Furthermore, when the phosphate group is introduced as a structural unit directly constituting part of the styrene-maleic anhydride copolymer backbone, the styrene-maleic anhydride copolymer backbone is formed by copolymerization of monomers including unsaturated phosphate ester monomers. The unsaturated phosphate monomer is selected from at least one of diethyl vinyl phosphate, hydroxypropyl methacrylate phosphate, hydroxyethyl acrylate phosphate, and triallyl phosphate.

[0014] The present invention also provides a method for preparing the above-mentioned refractory material dispersant, comprising the following steps: S1: Copolymerize styrene with maleic anhydride to obtain the styrene-maleic anhydride copolymer backbone; S2: The styrene-maleic anhydride copolymer backbone obtained in step S1 is subjected to an esterification grafting reaction with a mixture containing short-chain polyethylene glycol with a molecular weight of 400-600 and long-chain polyethylene glycol with a molecular weight of 800-1200 to obtain a comb-shaped copolymer intermediate with polyethylene glycol side chains. S3: React the terminal hydroxyl groups of the polyethylene glycol side chain of the comb copolymer intermediate obtained in step S2 with a phosphorylation reagent, followed by hydrolysis to introduce phosphate groups; S4: Post-processing to obtain the refractory material dispersant.

[0015] The present invention also provides another method for preparing the above-mentioned refractory material dispersant, comprising the following steps: A1: Styrene, maleic anhydride and unsaturated phosphate monomers are copolymerized to obtain a styrene-maleic anhydride copolymer backbone containing phosphate ester structural units. A2: The styrene-maleic anhydride copolymer backbone obtained in step A1 is subjected to an esterification grafting reaction with a mixture containing short-chain polyethylene glycol with a molecular weight of 400-600 and long-chain polyethylene glycol with a molecular weight of 800-1200. A3: Post-processing to obtain the refractory material dispersant.

[0016] Further, in step S2 or A2, the total amount of the polyethylene glycol mixture fed into the copolymer is in a molar ratio of 0.5 to 0.85:1 to the maleic anhydride structural unit in the main chain of the styrene-maleic anhydride copolymer in the corresponding step.

[0017] Furthermore, the esterification grafting reaction is carried out at 85–95°C in the presence of an esterification catalyst and a dehydrating agent.

[0018] Compared with the prior art, the beneficial effects of the present invention are: 1. By employing asymmetric compounding of polyethylene glycol side chains within a specific molecular weight range and controlling the esterification grafting degree to be 50%–85%, precise functional division of labor is achieved. Among them, short-chain polyethylene glycol has strong mobility and can quickly adsorb and anchor onto the surface of refractory material particles, providing excellent initial wetting and dispersing power, ensuring that the slurry has excellent construction fluidity; while long-chain polyethylene glycol fully extends in the medium to form a thick and stable steric hindrance layer, effectively preventing the particles from re-aggregating and settling under static or shear conditions, thus fundamentally solving the technical problem that traditional dispersants cannot simultaneously achieve high initial fluidity and long-term anti-settling properties and plasticity retention. 2. Phosphate groups are introduced into the structure. These groups can be located at the end of the polyethylene glycol side chain or in the main chain structural unit through chemical bonding. Phosphate groups have a stronger specific adsorption capacity with the surface of refractory material particles (especially those containing oxides such as aluminum, magnesium, and calcium) (e.g., forming hydrogen bonds or coordination bonds), which significantly enhances the adsorption strength and coverage of the dispersant on the particle surface and improves the dispersion efficiency. At the same time, phosphate groups themselves have good thermal stability, and their introduction further improves the tolerance of the dispersant during the high-temperature firing process of refractory materials. 3. This invention provides two clear synthetic routes: one is esterification followed by phosphating, and the other is copolymerization followed by phosphate ester unit introduction and then esterification. The reaction conditions for each step are clear and easy to control. By systematically controlling the ratio of main chain monomers, the ratio of side chain polyethylene glycols, the degree of esterification grafting, and the amount of phosphate groups introduced, the target molecular structure can be constructed accurately and reproducibly, thereby effectively ensuring a high degree of consistency in product quality between different production batches and meeting the stringent requirements of modern large-scale industrial production for the stability of additive performance.

[0019] Because the dispersant of this invention has more efficient dispersing ability and long-term stability, it helps to reduce its addition amount in refractory slurry while achieving the same or better construction performance, or reduce the amount of additional water required to maintain fluidity. It also helps to increase the solid content of the slurry, thereby improving the density of the green body after molding and the mechanical strength of the final product, thus improving the overall quality of refractory products and bringing potential cost benefits. Detailed Implementation

[0020] The technical solution of the present invention will be described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and are not intended to limit the present invention. Those skilled in the art can make various modifications and substitutions under the guidance of the inventive concept, without departing from the spirit and scope of the present invention.

[0021] The core of this invention lies in providing a copolymer-type refractory material dispersant with a comb-like structure. Its structural features include a styrene-maleic anhydride copolymer backbone with asymmetrically compounded polyethylene glycol (PEG) side chains grafted via ester bonds, and phosphate groups introduced through chemical bonding. These phosphate groups can be introduced in two ways: firstly, by bonding to the ends of the PEG side chains; and secondly, by participating in copolymerization as unsaturated phosphate ester monomers, becoming part of the backbone structural unit. By precisely controlling the backbone composition, the molecular weight and compounding ratio of the PEG side chains, the degree of esterification grafting, and the amount of phosphate groups introduced, a dispersant exhibiting excellent initial dispersibility, long-term anti-settling stability, and high thermal stability in refractory slurries can be obtained.

[0022] Example 1: A refractory material dispersant and its preparation method. This example demonstrates a method for preparing a refractory material by introducing phosphate groups to the ends of grafted PEG side chains. The method includes the following steps: Step 1: Under an inert atmosphere (such as nitrogen), add an organic solvent (such as toluene, xylene, or acetone), maleic anhydride, and a free radical initiator (such as benzoyl peroxide (BPO) or azobisisobutyronitrile (AIBN)) to a reactor equipped with a stirrer, thermometer, reflux condenser, and dropping device. Stir and heat to 70–85°C to dissolve the monomer. Dissolve styrene in a portion of the solvent and slowly add it dropwise to the reaction system through a dropping funnel, controlling the dropping time to 1–4 hours. After the addition is complete, continue the reaction at 75–85°C for 2–6 hours to obtain a styrene-maleic anhydride (SMA) copolymer solution. By adjusting the molar ratio of styrene to maleic anhydride, SMA copolymers with different segment ratios can be obtained, for example, molar ratios of 1:0.8, 1:1, 1:1.2, etc.

[0023] Step 2: Add to the SMA copolymer solution obtained in Step 1 a mixture of short-chain PEG (molecular weight (Mw): 400–600) and long-chain PEG (molecular weight (Mw): 800–1200), an esterification catalyst (such as p-toluenesulfonic acid (PTSA) or concentrated sulfuric acid), and a dehydrating agent (such as toluene or cyclohexane). The molar ratio of short-chain PEG to long-chain PEG can be selected between 1:0.5 and 1:2, for example, 1:0.5, 1:1, 1:1.5, 1:2.

[0024] The reaction system is heated to 85–95°C and esterification is carried out under stirring. Water generated during the reaction is removed via azeotropic separation. The reaction time is typically 4–8 hours. By controlling the molar ratio of the total PEG mixture to the maleic anhydride structural units in the SMA copolymer between 0.5:1 and 0.85:1, the degree of esterification grafting in the final product can be precisely controlled within the desired range of 50%–85%. For example, at a ratio of 0.5:1, the degree of esterification grafting is approximately 50%; at a ratio of 0.85:1, the degree of esterification grafting is approximately 85%. After the reaction, an SMA-g-PEG intermediate with a comb-like structure is obtained.

[0025] Step 3: Cool the above SMA-g-PEG intermediate solution to a suitable temperature (e.g., 0–10°C). Under stirring and an inert atmosphere, slowly add the phosphorylation reagent dropwise.

[0026] The phosphorylating agent can be selected from phosphorus oxychloride (POCl3), phosphorus tribromooxychloride (POBr3), or phosphorus pentachloride (PCl5), etc. Its function is to react with the hydroxyl groups at the end of the polyethylene glycol side chain to form a chlorinated phosphate intermediate or a brominated phosphate intermediate, which is then hydrolyzed to obtain a dihydrogen phosphate ester group. Preferably, the phosphorylating agent is phosphorus oxychloride (POCl3).

[0027] The hydroxyl groups at the ends of the PEG side chains react with phosphorus oxychloride (POCl3) to form phosphate chloride bonds. After the addition is complete, the reaction continues at low temperature for 1–3 hours. Subsequently, the reaction mixture is slowly heated to room temperature or slightly higher (e.g., 25–40°C), and an appropriate amount of water is added for hydrolysis, converting the phosphorus oxychloride (POCl3) groups into phosphate groups (-PO(OH)2). After the hydrolysis reaction is complete, a crude comb-like copolymer dispersant containing terminal phosphate groups is obtained.

[0028] Step 4: Post-process the reaction product to obtain a pure product. For example, wash with a weak alkaline aqueous solution (such as sodium bicarbonate solution) to neutralize residual acidic catalyst and byproduct hydrochloric acid, then wash with deionized water until neutral. Then remove the organic solvent by vacuum distillation or other suitable methods to finally obtain a viscous or solid refractory dispersant product, labeled as the SMP-A series. Example 2: A refractory material dispersant and its preparation method. This example demonstrates a preparation method that directly introduces phosphate-containing monomers into the main chain through copolymerization. It includes the following steps: Step 1: Under an inert atmosphere, add an organic solvent, maleic anhydride, unsaturated phosphate monomer, and a free radical initiator to the reactor. The unsaturated phosphate monomer may be selected from at least one of diethyl vinyl phosphate, hydroxypropyl methacrylate phosphate, hydroxyethyl acrylate phosphate, or triallyl phosphate. Stir and heat to 70–85°C. Dissolve styrene in a portion of the solvent and slowly add it dropwise to the reaction system. Through copolymerization, a styrene-maleic anhydride-unsaturated phosphate terpolymer is obtained. By adjusting the feed ratio of the three monomers, the phosphate group content in the main chain can be controlled. For example, the unsaturated phosphate monomer may account for 1%–20% of the total monomer molars.

[0029] Step 2: The terpolymer solution obtained in Step 1 is mixed with an asymmetrically compounded PEG mixture (short-chain PEG molecular weight (Mw) 400–600, long-chain PEG molecular weight (Mw) 800–1200, molar ratio 1:0.5–1:2), an esterification catalyst, and a dehydrating agent. The esterification grafting reaction is carried out at 85–95°C, controlling the total PEG feed amount to the molar ratio of maleic anhydride structural units in the copolymer to be 0.5:1 to 0.85:1, to obtain a product with an esterification grafting degree of 50%–85%. The water generated in the reaction is removed by azeotropic extraction.

[0030] Step 3: After the reaction is complete, the product is post-processed. For example, it is washed with alkali and water, and then the solvent is removed by vacuum distillation to obtain a comb-like copolymer dispersant product containing phosphate groups (located on the SMA copolymer backbone) and PEG side chains, labeled as the SMP-B series.

[0031] To verify the superior performance of the dispersant of the present invention, several dispersant samples of the present invention with different parameters (including SMP-A and SMP-B series) and several comparative sample samples were prepared for comparative testing.

[0032] Sample 1 of this invention (SMP-A1): prepared according to the method of Example 1. The SMA main chain styrene:maleic anhydride = 1:1, the PEG side chain is a mixture of PEG-400 (short chain) and PEG-1000 (long chain) in a molar ratio of 1:1, the total feed ratio (PEG:MA) = 0.6:1, the theoretical esterification grafting degree is 60%, and the phosphate group is located at the end of the polyethylene glycol side chain.

[0033] Sample 2 of this invention (SMP-A2): prepared according to the method of Example 1. The SMA main chain styrene:maleic anhydride = 1:1, the PEG side chain is a mixture of PEG-600 (short chain) and PEG-1200 (long chain) in a molar ratio of 1:0.5, the total feed ratio (PEG:MA) = 0.75:1, the theoretical esterification grafting degree is 75%, and the phosphate group is located at the end of the polyethylene glycol side chain.

[0034] Sample 3 of this invention (SMP-B1): Prepared according to the method of Example 2. The main chain is a copolymer of styrene, maleic anhydride and hydroxypropyl methacrylate phosphate (molar ratio 10:9:1), the PEG side chains are a blend of PEG-500 (short chain) and PEG-800 (long chain) in a molar ratio of 1:2, the total feed ratio (PEG:MA) = 0.7:1, and the theoretical esterification grafting degree is 70%.

[0035] Comparative Sample 1 (CP-1): Commercially available sodium tripolyphosphate (STPP) dispersant.

[0036] Comparative Sample 2 (CP-2): Dispersant prepared according to the method of Example 1 using only a single molecular weight PEG-600, with a total feed ratio (PEG:MA) of 0.6:1, and without phosphate groups.

[0037] Comparative Sample 3 (CP-3): Prepared according to the method of Example 1, but with a total PEG feed ratio (PEG:MA) as high as 1.0:1, in an attempt to obtain a product with an ultra-high esterification grafting degree (>90%). The PEG is a blend of PEG-400 and PEG-1000 (1:1).

[0038] Comparative Sample 4 (CP-4): Prepared according to the method of Example 1, but without the phosphating reaction in step 3. SMA main chain styrene:maleic anhydride = 1:1, PEG side chains are a mixture of PEG-400 (short chain) and PEG-1000 (long chain) in a molar ratio of 1:1, total feed ratio (PEG:MA) = 0.6:1, theoretical esterification grafting degree 60%.

[0039] Comparative Sample 5 (CP-5): Prepared according to the method of Example 1, containing phosphate groups, but using a single molecular weight PEG-1000 as a side chain, with a total feed ratio (PEG:MA) of 0.6:1.

[0040] Performance testing methods: Slurry flowability test: Referring to relevant industry standards (such as GB / T8077), prepare magnesium-aluminum refractory castable slurries with a fixed water-to-solid ratio, and add 0.2% of the above-mentioned dispersant by weight of the dry powder. Test the initial flowability of the slurry and the flowability after standing for 30 minutes, and calculate the flowability retention rate (%) = (30-minute flowability / initial flowability) × 100%.

[0041] Slurry settling stability test: Pour the prepared slurry into a stoppered graduated cylinder, let it stand for 2 hours, observe and record the height of the upper clear liquid and the total height of the slurry, and calculate the settling rate (%) = ((total height - clear liquid height) / total height) × 100%. The lower the settling rate, the better the settling resistance.

[0042] Thermal stability test (TGA): A thermogravimetric analyzer was used to heat the dispersant sample at a rate of 10 °C / min under a nitrogen atmosphere. The temperature at which the mass of the prepared dispersant sample was reduced by 5% (Td5%) was recorded as a reference for the initial decomposition temperature to evaluate the thermal stability of the dispersant.

[0043] The results of the dispersion performance test of the dispersant in refractory materials are shown in Table 1 below, and the results of the thermal stability test are shown in Table 2 below. Table 1: Comparison of performance test results of slurries prepared from different samples

[0044] Table 2: Thermal stability test of dispersants

[0045] Results analysis: 1. Compared with Comparative Example 1 (conventional dispersant), the slurries formulated from all samples of this invention (SMP-A1, SMP-A2, SMP-B1) showed significantly better initial fluidity, fluidity retention, and anti-settling properties than commercially available sodium tripolyphosphate (CP-1). This demonstrates that the comb-like copolymer structure and the introduction of phosphate groups in this invention result in superior dispersion efficiency and steric stability.

[0046] 2. Compared with Comparative Example 2 (no compounding, no phosphate), although the slurry prepared by CP-2 has a certain initial fluidity, its fluidity retention rate (89.6%) and anti-settling properties (settling rate 14.8%) are significantly worse than those of the slurry prepared by the sample of this invention. This indicates that it is difficult to achieve long-term stable dispersion by relying solely on a single molecular weight PEG side chain. The combination of "asymmetric compounded PEG side chain + phosphate group" used in this invention is a necessary condition for obtaining excellent comprehensive performance.

[0047] 3. The individual effects and synergistic effects of each technical feature: 3.1 Comparing Comparative Example 4 (with compounding, without phosphate) and Comparative Example 2 (without compounding, without phosphate), the slurry prepared with CP-4 showed better fluidity retention (94.2%) and anti-settling properties (settling rate 6.5%) than the slurry prepared with Comparative Example 2 (89.6%, 14.8%). This demonstrates that using asymmetrically compounded polyethylene glycol side chains is a key factor in improving the long-term stability of the slurry. From a molecular design perspective, this is because short-chain PEG has a higher migration rate and can quickly adsorb onto the particle surface (rapid anchoring), corresponding to higher initial fluidity; long-chain PEG (such as PEG-1000) can form a thicker steric hindrance layer around the particles (steric hindrance), effectively hindering particle aggregation, thereby improving the long-term stability of the slurry. The test results of CP-4 validate the effectiveness of this design concept.

[0048] 3.2 Comparing Comparative Example 5 (with phosphate, no compounding) and Comparative Example 2 (without phosphate, no compounding), the slurry prepared with CP-5 showed better fluidity retention (91.5%) and anti-settling properties (settling rate 12.0%) than the slurry prepared with CP-2. This demonstrates that the introduction of phosphate groups enhances the adsorption strength of the dispersant on the particle surface, thereby independently improving dispersion stability. Simultaneously, the Td5% (325℃) of CP-5 was significantly higher than that of CP-2 (305℃) and CP-4 (306℃) without phosphate, verifying the effect of phosphate groups on improving the thermal stability of the dispersant itself.

[0049] 3.3 The performance of the slurry formulated with the samples of this invention (such as SMP-A1, which simultaneously contains compounded PEG and phosphate groups) (flowability retention rate 96.0%, sedimentation rate 5.2%, Td5% at 328℃) is significantly better than that of the slurry formulated with only one feature, CP-4 and CP-5, and far superior to the slurry formulated with neither feature, CP-2. The combined performance of the slurry formulated with CP-4 and CP-5 in terms of flowability retention rate and sedimentation rate is still far lower than that of the slurry formulated with SMP-A1. This strongly demonstrates that the "asymmetric compounded PEG side chains" and "phosphate groups" are not simply functional additives, but rather produce a significant synergistic effect. The strong adsorption anchor provided by the phosphate groups, combined with the dense and stable steric hindrance layer formed by the compounded PEG side chains, jointly constructs a dynamically stable dispersion system with extremely strong anti-interference capabilities, thus achieving a dual breakthrough in flowability and long-term stability.

[0050] 4. Compared with Comparative Example 3 (excessively high esterification grafting degree), although the slurry prepared with CP-3 had the highest initial fluidity, its retention rate and anti-settling properties were inferior to those of the slurry prepared by controlling the esterification grafting degree within the range of 50%–85% according to this invention. This verifies the importance of controlling the esterification grafting degree within the range of 50%–85%. Excessively high esterification grafting degree may lead to overcrowding of molecular chains, affecting the side chain conformation and adsorption behavior, which is detrimental to long-term stability.

[0051] 5. The initial decomposition temperature (Td5%) of the samples of the present invention is higher than that of the comparative samples CP-2, CP-3 and CP-4. This is due to the good thermal stability of the phosphate group itself, which makes the dispersant of the present invention more suitable for the high-temperature processing environment of refractory materials.

[0052] The parts of this invention not described in detail are prior art. It will be apparent to those skilled in the art that this invention is not limited to the details of the above exemplary embodiments, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the above embodiments should be regarded as exemplary and non-limiting in all respects. The scope of this invention is defined by the appended claims rather than the foregoing description, and therefore all changes falling within the meaning and scope of the equivalents of the claims are intended to be included within this invention.

Claims

1. A refractory material dispersant, characterized in that, It is a comb-like copolymer comprising a styrene-maleic anhydride copolymer backbone, polyethylene glycol side chains grafted onto the styrene-maleic anhydride copolymer backbone via ester bonds, and phosphate groups; the phosphate groups are introduced into the copolymer by chemical bonding, either by bonding to the ends of the polyethylene glycol side chains or by directly forming part of the styrene-maleic anhydride copolymer backbone as structural units; The polyethylene glycol side chains include short-chain polyethylene glycol with a molecular weight of 400-600 and long-chain polyethylene glycol with a molecular weight of 800-1200.

2. The refractory material dispersant according to claim 1, characterized in that: The degree of esterification grafting of the polyethylene glycol side chain is 50% to 85%.

3. The refractory material dispersant according to claim 1, characterized in that: The molar ratio of short-chain polyethylene glycol to long-chain polyethylene glycol is 1:0.5 to 1:

2.

4. The refractory material dispersant according to claim 1, characterized in that: In the styrene-maleic anhydride copolymer backbone, the molar ratio of styrene structural units to maleic anhydride structural units is 1:0.8 to 1:1.

2.

5. The refractory material dispersant according to claim 1, characterized in that: When the phosphate group is introduced in a manner that is bonded to the end of the polyethylene glycol side chain, it is formed by the reaction of the hydroxyl group at the end of the polyethylene glycol side chain with a phosphorylating agent.

6. The refractory material dispersant according to claim 1, characterized in that: When the phosphate group is introduced as a structural unit directly forming part of the styrene-maleic anhydride copolymer backbone, the styrene-maleic anhydride copolymer backbone is formed by copolymerization of monomer combinations including unsaturated phosphate ester monomers. The unsaturated phosphate monomer is selected from at least one of diethyl vinyl phosphate, hydroxypropyl methacrylate phosphate, hydroxyethyl acrylate phosphate, and triallyl phosphate.

7. A method for preparing the refractory material dispersant as described in claim 5, characterized in that: Includes the following steps: S1: Copolymerize styrene with maleic anhydride to obtain the styrene-maleic anhydride copolymer backbone; S2: The styrene-maleic anhydride copolymer backbone obtained in step S1 is subjected to an esterification grafting reaction with a mixture containing short-chain polyethylene glycol with a molecular weight of 400-600 and long-chain polyethylene glycol with a molecular weight of 800-1200 to obtain a comb-shaped copolymer intermediate with polyethylene glycol side chains. S3: React the terminal hydroxyl groups of the polyethylene glycol side chain of the comb copolymer intermediate obtained in step S2 with a phosphorylation reagent, followed by hydrolysis to introduce phosphate groups; S4: Post-processing to obtain the refractory material dispersant.

8. A method for preparing the refractory material dispersant as described in claim 6, characterized in that: Includes the following steps: A1: Styrene, maleic anhydride and unsaturated phosphate monomers are copolymerized to obtain a styrene-maleic anhydride copolymer backbone containing phosphate ester structural units. A2: The styrene-maleic anhydride copolymer backbone obtained in step A1 is subjected to an esterification grafting reaction with a mixture containing short-chain polyethylene glycol with a molecular weight of 400-600 and long-chain polyethylene glycol with a molecular weight of 800-1200. A3: Post-processing to obtain the refractory material dispersant.

9. The method for preparing the refractory material dispersant according to claim 7 or 8, characterized in that: In step S2 or A2, the total amount of the polyethylene glycol mixture fed into the copolymer is in a molar ratio of 0.5 to 0.85:1 to the maleic anhydride structural unit in the main chain of the styrene-maleic anhydride copolymer in the corresponding step.

10. The method for preparing the refractory material dispersant according to claim 7 or 8, characterized in that, The esterification grafting reaction was carried out at 85–95 °C in the presence of an esterification catalyst and a dehydrating agent.

Images