Polycarboxylic acid sodium salt dispersing agent for rubber as well as preparation method and application of polycarboxylic acid sodium salt dispersing agent

Abstract

The invention relates to the technical field of dispersing agents, and particularly discloses a sodium polycarboxylate dispersing agent for rubber as well as a preparation method and application of the sodium polycarboxylate dispersing agent. The preparation method of the polycarboxylic acid sodium salt dispersing agent for rubber comprises the following steps: mixing deionized water, alkenylated montmorillonite, acrylic acid, allyl polyethylene glycol, maleic anhydride, allyl polyoxyethylene ether, phenyl methacrylate, glycidyl methacrylate and an initiator for reaction, adjusting the pH value by using a sodium hydroxide aqueous solution, filtering, washing and drying to obtain the polycarboxylic acid sodium salt dispersing agent for rubber. The polycarboxylic acid sodium salt structure is beneficial to formation of a stable dispersion system, provides dispersion force, prevents agglomeration of rubber particles in the processing process, has high heat resistance, excellent dispersion efficiency and strong interface bonding force, can reduce filler agglomeration in the rubber processing process, improves the dispersion efficiency, and improves the dispersion efficiency. The rubber is suitable for high-performance tires, sealing elements and other rubber products.

Description

Technical Field

[0001] The invention relates to the technical field of dispersants, in particular to a sodium polycarboxylate dispersant for rubber and a preparation method and application thereof. Background Art

[0002] In the rubber processing, dispersants play a vital role. They can reduce the interaction between filler particles and enable the filler to be more effectively dispersed in the rubber. The uniformity of filler dispersion directly affects the mechanical properties and processing efficiency of rubber products. Traditional dispersants mainly rely on electrostatic repulsion to achieve dispersion, and have insufficient adsorption strength. They are prone to desorption under high temperature or high shear conditions, causing filler agglomeration in the rubber matrix, causing defects in the rubber matrix interface, and reducing the overall performance of the product. Traditional dispersants have poor tolerance and are prone to failure in complex processing systems. Polycarboxylate dispersants, with their unique multi-branched structure, achieve excellent stable dispersion performance by exerting steric hindrance effects, and are therefore increasingly widely used in the rubber field.

[0003] However, conventional polycarboxylate dispersants have relatively simple functions, and the interfacial bonding between the hydrophilic groups of polycarboxylates and the hydrophobic rubber molecular chains is weak, which can easily lead to segregation and scaling, affecting processing performance. At the same time, the mixing degree of rubber is high, and the dispersant is prone to thermal decomposition, affecting the performance of the rubber.

[0004] Therefore, there is an urgent need to develop a polycarboxylate sodium salt dispersant specifically for rubber processing that has excellent high temperature resistance, as well as excellent dispersibility and compatibility, to meet the needs of the rubber industry for high-performance and green development. Summary of the invention

[0005] 1. Technical issues to be solved

[0006] In view of the deficiencies in the prior art, the present invention provides a sodium polycarboxylate dispersant for rubber and a preparation method and application thereof, and provides a sodium polycarboxylate dispersant for rubber with excellent heat resistance and dispersibility.

[0007] (II) Technical solution

[0008] In order to achieve the above object, the present invention discloses a method for preparing a sodium polycarboxylate dispersant for rubber, comprising the following steps:

[0009] S1. Ultrasonic dispersion of nano-montmorillonite in an ethanol solution, after uniform dispersion, adding γ-glycidyloxypropyltrimethoxysilane, stirring and mixing, adjusting the pH to 4-5 with glacial acetic acid, reacting, cooling after the reaction, washing with anhydrous ethanol, and vacuum drying at 60° C. for 24 h to obtain epoxidized montmorillonite;

[0010] S2, ultrasonically dispersing the epoxidized montmorillonite in N,N-dimethylformamide, after uniform dispersion, adding aminopropyl di-terminated polydimethylsiloxane, stirring and mixing, reacting, after the reaction is completed, centrifuging, the speed of centrifugation is 8000r / min, the time of centrifugation is 8min, washing with anhydrous ethanol, vacuum drying at 80°C for 12h, to obtain amino-modified montmorillonite;

[0011] S3, ultrasonically dispersing the amino-modified montmorillonite in N,N-dimethylformamide, adding acryloyl chloride and triethylamine, stirring and mixing, reacting, and after the reaction is completed, filtering, washing with anhydrous ethanol, and drying at 60° C. for 24 hours to obtain olefinated montmorillonite;

[0012] S4. Evenly mix deionized water, olefinated montmorillonite, acrylic acid, allyl polyethylene glycol, maleic anhydride, allyl polyoxyethylene ether, phenyl methacrylate, glycidyl methacrylate and initiator, heat up and react. After the reaction is completed, cool and adjust the pH with sodium hydroxide aqueous solution. The pH of the product is 7-8, and a sodium polycarboxylate dispersant for rubber is obtained.

[0013] Preferably, in step S1, the mass ratio of nano-montmorillonite, ethanol solution and γ-glycidyloxypropyltrimethoxysilane is 100:5800-7500:50-70.

[0014] Preferably, the reaction temperature in step S1 is 75-90° C., and the reaction time is 2-5 h.

[0015] Preferably, the ethanol solution in step S1 is a 50%wt ethanol aqueous solution.

[0016] Preferably, in step S2, the mass ratio of epoxidized montmorillonite, N,N-dimethylformamide, and aminopropyl di-terminated polydimethylsiloxane is 100:2100-2400:185-215.

[0017] Preferably, the reaction temperature in step S2 is 60-70° C., and the reaction time is 4-6 h.

[0018] Preferably, in step S3, the mass ratio of amino-modified montmorillonite, N,N-dimethylformamide, acryloyl chloride and triethylamine is 100:1200-1500:58-75:30-50.

[0019] Preferably, the reaction temperature in step S3 is 25-35° C., and the reaction time is 6-9 h.

[0020] Preferably, in step S4, the mass ratio of deionized water, acrylic acid, olefinic montmorillonite, allyl polyethylene glycol, maleic anhydride, allyl polyoxyethylene ether, phenyl methacrylate, glycidyl methacrylate, and initiator is 600-750:100:3-5:120-150:24-35:8-14:7-10:4-7:5-12.

[0021] Preferably, the reaction temperature in step S4 is 70-80° C., and the reaction time is 4-6 h.

[0022] Preferably, the initiator in step S4 is ammonium persulfate.

[0023] Preferably, the concentration of the sodium hydroxide aqueous solution in step S4 is 0.1 mol / L.

[0024] A sodium polycarboxylate dispersant for rubber prepared by the method for preparing the sodium polycarboxylate dispersant for rubber.

[0025] An application of the polycarboxylate sodium salt dispersant for rubber in rubber processing.

[0026] (III) Beneficial technical effects

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) In the present invention, γ-glycidyloxypropyltrimethoxysilane is used to modify nano-montmorillonite, and epoxy groups are introduced on the surface of nano-montmorillonite to provide reaction sites for subsequent amination, thereby obtaining epoxidized montmorillonite. The epoxy groups on the surface of epoxidized montmorillonite and the amino groups on the aminopropyl double-terminated polydimethylsiloxane undergo epoxy ring-opening reaction, and hydroxyl groups and unreacted amino groups on the aminopropyl double-terminated polydimethylsiloxane are introduced on the surface of montmorillonite to obtain amino-modified montmorillonite. The amino groups on the amino-modified montmorillonite react with the acyl chloride groups on the acryloyl chloride to introduce carbon-carbon double bonds to obtain olefinated montmorillonite. In a deionized water solvent, olefinated montmorillonite, acrylic acid, allyl polyethylene glycol, maleic anhydride, allyl polyoxyethylene ether, phenyl methacrylate, and glycidyl methacrylate are polymerized under the action of an initiator to form a hybrid structure, a synergistic effect, and enhanced interface bonding, and then under the action of sodium hydroxide, a polycarboxylic acid sodium salt dispersant for rubber is obtained.

[0029] (2) In the present invention, nano-montmorillonite is used as a basic filler, and its layered structure can provide physical barriers and has excellent heat resistance. The modification of nano-montmorillonite effectively avoids the agglomeration of nano-montmorillonite, can improve the dispersion stability, and at the same time improve the heat resistance, which is suitable for high-temperature rubber processing environments. Aminopropyl di-terminated polydimethylsiloxane is introduced on the nano-montmorillonite, which not only provides amino reaction sites, but also introduces siloxane segments. The hydrophobicity of the silicone main chain and the hydrophilicity of the polycarboxylate complement each other, reduce interfacial tension, and the steric hindrance effect of the siloxane segment further inhibits particle aggregation, thereby improving the compatibility and thermal stability of the dispersant.

[0030] (3) In the present invention, each monomer forms a main chain through double bond polymerization, which can form a cross-linked network. The olefinated montmorillonite is embedded in the polymer network as a nano-cross-linking point, which can form a multifunctional dispersant with charge repulsion, steric hindrance and interface anchoring. The acrylic acid introduced into the main chain structure can provide a carboxylic acid group, which forms a charge repulsion effect after neutralization. The POE segment in the allyl polyoxyethylene ether has a flexible segment structure and an excellent steric hindrance effect, which can inhibit filler agglomeration. Maleic anhydride can increase the carboxylic acid density, optimize the charge distribution, and enhance the adsorption capacity. Phenyl methacrylate increases the hydrophobic monomer, adjusts the hydrophilic-hydrophobic balance, and enhances the compatibility with rubber. The epoxy group of glycidyl methacrylate can participate in cross-linking during rubber vulcanization and improve the mechanical properties of the rubber. The introduction of allyl polyethylene glycol makes the polycarboxylate sodium salt dispersant have longer side chains and higher molecular weight, thereby enhancing its adsorption capacity and steric hindrance effect on the surface of rubber particles, effectively reducing the interaction between rubber particles, improving the dispersion stability of rubber particles in water, preventing particle agglomeration and sedimentation, and improving the applicability of the dispersant. Furthermore, the polyethylene glycol segment is hydrophilic and can form hydrogen bonds with water molecules, so that the dispersant molecules are adsorbed on the surface of rubber particles.

[0031] (4) The polycarboxylate sodium salt structure prepared in the present invention helps to form a stable dispersion system, provides dispersing force, and prevents rubber particles from agglomerating during processing. The prepared polycarboxylate sodium salt dispersant has high heat resistance, excellent dispersion efficiency and strong interface bonding force. The active groups introduced into the dispersant can be combined with the surface of fillers such as carbon black and white carbon black in the rubber processing process through chemical adsorption, thereby reducing filler agglomeration and improving dispersion efficiency. The polycarboxylate sodium salt dispersant is suitable for high-performance tires, seals and other rubber products. DETAILED DESCRIPTION

[0032] In order to facilitate the understanding of the present invention, the present invention will be described more fully below. Preferred embodiments of the present invention are given below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0033] Example 1

[0034] A method for preparing a sodium polycarboxylate dispersant for rubber comprises the following steps:

[0035] S1. Ultrasonic dispersion of nano-montmorillonite in 50%wt ethanol aqueous solution, after uniform dispersion, adding γ-glycidyloxypropyltrimethoxysilane, wherein the mass ratio of nano-montmorillonite, ethanol solution and γ-glycidyloxypropyltrimethoxysilane is 100:5800:50, stirring and mixing, adjusting the pH to 4 with glacial acetic acid, reacting, the reaction temperature is 75°C, the reaction time is 5h, after the reaction is completed, cooling, washing with anhydrous ethanol, and vacuum drying at 60°C for 24h to obtain epoxidized montmorillonite;

[0036] S2, ultrasonically dispersing the epoxidized montmorillonite in N,N-dimethylformamide, after uniform dispersion, adding aminopropyl dicapped polydimethylsiloxane, wherein the mass ratio of the epoxidized montmorillonite, N,N-dimethylformamide, and aminopropyl dicapped polydimethylsiloxane is 100:2100:185, stirring and mixing, reacting, the reaction temperature is 60°C, the reaction time is 6h, after the reaction is completed, centrifugation is performed, the speed of centrifugation is 8000r / min, the time of centrifugation is 8min, washing with anhydrous ethanol, vacuum drying at 80°C for 12h, to obtain amino-modified montmorillonite;

[0037] S3, ultrasonically dispersing the amino-modified montmorillonite in N,N-dimethylformamide, adding acryloyl chloride and triethylamine, wherein the mass ratio of the amino-modified montmorillonite, N,N-dimethylformamide, acryloyl chloride and triethylamine is 100:1200:58:30, stirring and mixing, reacting, the reaction temperature is 25°C, the reaction time is 9h, after the reaction is completed, filtering, washing with anhydrous ethanol, and drying at 60°C for 24h to obtain olefinated montmorillonite;

[0038] S4. Evenly mix deionized water, acrylic acid, olefinic montmorillonite, allyl polyethylene glycol, maleic anhydride, allyl polyoxyethylene ether, phenyl methacrylate, glycidyl methacrylate and initiator ammonium persulfate in a mass ratio of 600:100:3:120:24:8:7:4:5, heat up and react at 70°C for 6 hours. After the reaction is completed, cool and adjust the pH with aqueous sodium hydroxide solution. The pH of the product is 7 to obtain a sodium polycarboxylate dispersant for rubber.

[0039] Example 2

[0040] A method for preparing a sodium polycarboxylate dispersant for rubber comprises the following steps:

[0041] S1. Ultrasonic dispersion of nano-montmorillonite in 50%wt ethanol aqueous solution, after uniform dispersion, adding γ-glycidyloxypropyltrimethoxysilane, wherein the mass ratio of nano-montmorillonite, ethanol solution and γ-glycidyloxypropyltrimethoxysilane is 100:6800:60, stirring and mixing, adjusting the pH to 4.5 with glacial acetic acid, reacting, the reaction temperature is 85°C, the reaction time is 4h, after the reaction is completed, cooling, washing with anhydrous ethanol, and vacuum drying at 60°C for 24h to obtain epoxidized montmorillonite;

[0042] S2, ultrasonically dispersing the epoxidized montmorillonite in N,N-dimethylformamide, after uniform dispersion, adding aminopropyl dicapped polydimethylsiloxane, wherein the mass ratio of the epoxidized montmorillonite, N,N-dimethylformamide, and aminopropyl dicapped polydimethylsiloxane is 100:2250:200, stirring and mixing, reacting, the reaction temperature is 65°C, the reaction time is 5h, after the reaction is completed, centrifugation is performed, the speed of centrifugation is 8000r / min, the time of centrifugation is 8min, washing with anhydrous ethanol, vacuum drying at 80°C for 12h, to obtain amino-modified montmorillonite;

[0043] S3, ultrasonically dispersing the amino-modified montmorillonite in N,N-dimethylformamide, adding acryloyl chloride and triethylamine, wherein the mass ratio of the amino-modified montmorillonite, N,N-dimethylformamide, acryloyl chloride and triethylamine is 100:1350:65:40, stirring and mixing, reacting, the reaction temperature is 30°C, the reaction time is 8h, after the reaction is completed, filtering, washing with anhydrous ethanol, and drying at 60°C for 24h to obtain olefinated montmorillonite;

[0044] S4. Evenly mix deionized water, acrylic acid, olefinic montmorillonite, allyl polyethylene glycol, maleic anhydride, allyl polyoxyethylene ether, phenyl methacrylate, glycidyl methacrylate and initiator ammonium persulfate in a mass ratio of 680:100:3.5:135:28:10:8:5:9, heat up and react at 75°C for 5 hours. After the reaction is completed, cool and adjust the pH with sodium hydroxide aqueous solution. The pH of the product is 7.5 to obtain a sodium polycarboxylate dispersant for rubber.

[0045] Example 3

[0046] A method for preparing a sodium polycarboxylate dispersant for rubber comprises the following steps:

[0047] S1. Evenly mix deionized water, acrylic acid, olefinic montmorillonite, allyl polyethylene glycol, maleic anhydride, allyl polyoxyethylene ether, phenyl methacrylate, glycidyl methacrylate and initiator ammonium persulfate in a mass ratio of 720:100:4.5:145:32:12:9:6:11, heat up and react at 75°C for 5 hours. After the reaction is completed, cool and adjust the pH with sodium hydroxide aqueous solution. The pH of the product is 7.5 to obtain a sodium polycarboxylate dispersant for rubber.

[0048] The preparation method of the olefinated montmorillonite is the same as the preparation method of the olefinated montmorillonite in Example 2.

[0049] Example 4

[0050] A method for preparing a sodium polycarboxylate dispersant for rubber comprises the following steps:

[0051] S1. Ultrasonic dispersion of nano-montmorillonite in 50%wt ethanol aqueous solution, after uniform dispersion, adding γ-glycidyloxypropyltrimethoxysilane, wherein the mass ratio of nano-montmorillonite, ethanol solution and γ-glycidyloxypropyltrimethoxysilane is 100:7500:70, stirring and mixing, adjusting the pH to 5 with glacial acetic acid, reacting, the reaction temperature is 90°C, the reaction time is 2h, after the reaction is completed, cooling, washing with anhydrous ethanol, and vacuum drying at 60°C for 24h to obtain epoxidized montmorillonite;

[0052] S2, ultrasonically dispersing the epoxidized montmorillonite in N,N-dimethylformamide, after uniform dispersion, adding aminopropyl dicapped polydimethylsiloxane, wherein the mass ratio of the epoxidized montmorillonite, N,N-dimethylformamide, and aminopropyl dicapped polydimethylsiloxane is 100:2400:215, stirring and mixing, reacting, the reaction temperature is 70°C, the reaction time is 4h, after the reaction is completed, centrifugation is performed, the speed of centrifugation is 8000r / min, the time of centrifugation is 8min, washing with anhydrous ethanol, vacuum drying at 80°C for 12h, to obtain amino-modified montmorillonite;

[0053] S3, ultrasonically dispersing the amino-modified montmorillonite in N,N-dimethylformamide, adding acryloyl chloride and triethylamine, wherein the mass ratio of the amino-modified montmorillonite, N,N-dimethylformamide, acryloyl chloride and triethylamine is 100:1500:75:50, stirring and mixing, reacting, the reaction temperature is 35°C, the reaction time is 6h, after the reaction is completed, filtering, washing with anhydrous ethanol, and drying at 60°C for 24h to obtain olefinated montmorillonite;

[0054] S4. Evenly mix deionized water, acrylic acid, olefinic montmorillonite, allyl polyethylene glycol, maleic anhydride, allyl polyoxyethylene ether, phenyl methacrylate, glycidyl methacrylate and initiator ammonium persulfate in a mass ratio of 750:100:5:150:35:14:10:7:12, heat up and react at 80°C for 4 hours. After the reaction is completed, cool and adjust the pH with sodium hydroxide aqueous solution. The pH of the product is 8 to obtain a sodium polycarboxylate dispersant for rubber.

[0055] Comparative Example 1

[0056] A method for preparing a polycarboxylate sodium salt dispersant comprises the following steps:

[0057] S1. Ultrasonic dispersion of nano-montmorillonite in 50%wt ethanol aqueous solution, after uniform dispersion, adding γ-methacryloxypropyltrimethoxysilane, wherein the mass ratio of nano-montmorillonite, ethanol solution and γ-methacryloxypropyltrimethoxysilane is 100:6800:60, stirring and mixing, reacting, the reaction temperature is 85°C, the reaction time is 4h, after the reaction is completed, cooling, washing with anhydrous ethanol, and vacuum drying at 60°C for 24h to obtain olefinated montmorillonite;

[0058] S2. Evenly mix deionized water, acrylic acid, olefinic montmorillonite, allyl polyethylene glycol, maleic anhydride, allyl polyoxyethylene ether, phenyl methacrylate, glycidyl methacrylate and initiator ammonium persulfate in a mass ratio of 720:100:4.5:145:32:12:9:6:11, heat up and react at 75°C for 5 hours. After the reaction is completed, cool and adjust the pH with sodium hydroxide aqueous solution. The pH of the product is 7.5 to obtain a sodium polycarboxylate dispersant.

[0059] Comparative Example 2

[0060] A method for preparing a polycarboxylate sodium salt dispersant comprises the following steps:

[0061] S1. Ultrasonic dispersion of nano-montmorillonite in 50%wt ethanol aqueous solution, after uniform dispersion, adding γ-glycidyloxypropyltrimethoxysilane, wherein the mass ratio of nano-montmorillonite, ethanol solution and γ-glycidyloxypropyltrimethoxysilane is 100:6800:60, stirring and mixing, adjusting the pH to 4.5 with glacial acetic acid, reacting, the reaction temperature is 85°C, the reaction time is 4h, after the reaction is completed, cooling, washing with anhydrous ethanol, and vacuum drying at 60°C for 24h to obtain epoxidized montmorillonite;

[0062] S2. Evenly mix deionized water, acrylic acid, epoxidized montmorillonite, aminopropyl dicapped polydimethylsiloxane, allyl polyethylene glycol, maleic anhydride, allyl polyoxyethylene ether, phenyl methacrylate, glycidyl methacrylate and initiator ammonium persulfate in a mass ratio of 720:100:1.5:3:145:32:12:9:6:11, heat up and react at 75°C for 5 hours. After the reaction is completed, cool and adjust the pH with sodium hydroxide aqueous solution. The pH of the product is 7.5 to obtain a sodium polycarboxylate dispersant.

[0063] Comparative Example 3

[0064] A method for preparing a polycarboxylate sodium salt dispersant comprises the following steps:

[0065] S1. Evenly mix deionized water, acrylic acid, olefinated montmorillonite, phenyl methacrylate, glycidyl methacrylate and initiator ammonium persulfate in a mass ratio of 720:289:4.5:9:6:11, heat up and react at 75°C for 5 hours. After the reaction is completed, cool and adjust the pH with sodium hydroxide aqueous solution. The pH of the product is 7.5 to obtain a sodium polycarboxylate dispersant.

[0066] The preparation method of the olefinated montmorillonite is the same as the preparation method of the olefinated montmorillonite in Example 2.

[0067] The nano-montmorillonite used in the examples and comparative examples of the present invention was purchased from Zhejiang Baina Chemical Co., Ltd., with a particle size of 50-100 nm; the CAS number of aminopropyl di-terminated polydimethylsiloxane is 106214-84-0; other raw materials and reagents not specified are commercially available.

[0068] The polycarboxylate sodium salt dispersants prepared in Examples 1-4 and Comparative Examples 1-3 were subjected to relevant performance tests, as follows:

[0069] (1) Dispersibility test: Weigh 2 g of carbon black as rubber filler, add 0.06 g of the polycarboxylate sodium salt dispersant prepared above and 50 mL of toluene solvent, respectively, and disperse by ultrasonic for 30 min to obtain a suspension. Place the suspension in a 100 mL measuring cylinder and let stand at room temperature for 24 h. Observe the sedimentation of the suspension and record the height of the sedimentation layer after 24 h.

[0070] (2) Heat resistance test: The sample was freeze-dried at -50°C, ground, and 5 mg of the sample was weighed for thermogravimetric analysis. The test was conducted in a nitrogen atmosphere at a heating rate of 10°C / min. The decomposition temperature T corresponding to 5% weight loss was measured. d ;

[0071] The above test results are shown in Table 1:

[0072] Table 1

[0073]

[0074] According to the test results of Table 1, it can be seen that the polycarboxylate sodium salt dispersing agent corresponding to Examples 1-4 of the present invention has excellent heat resistance and dispersibility. In Comparative Example 1, γ-methacryloxypropyltrimethoxysilane is used to modify nano-montmorillonite to obtain olefinic montmorillonite, and the olefinic montmorillonite is used as a raw material and added to the polymerization reaction to prepare a polycarboxylate sodium salt dispersing agent. Aminopropyl di-terminated polydimethylsiloxane is not introduced, and the surface activity of montmorillonite is reduced, and the compatibility in the matrix is ​​deteriorated, which has a certain effect on the dispersibility, and the heat resistance is reduced. In Comparative Example 2, epoxidized montmorillonite and aminopropyl di-terminated polydimethylsiloxane are used instead of olefinic montmorillonite to prepare a polycarboxylate sodium salt dispersing agent, and the sedimentation height becomes larger, the dispersibility of the nano-montmorillonite deteriorates, the sedimentation height increases, the dispersibility of the matrix deteriorates, and the heat resistance is affected. In Comparative Example 3, acrylic acid is used instead of allyl polyethylene glycol, maleic anhydride, and allyl polyoxyethylene ether, which weakens the steric hindrance and electrostatic repulsion, greatly reduces the dispersibility, and also changes the heat resistance.

[0075] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that all equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A method for preparing a sodium polycarboxylate dispersant for rubber, characterized in that: The steps include: S1. Ultrasonic dispersion of nano-montmorillonite in an ethanol solution, after uniform dispersion, adding γ-glycidyloxypropyltrimethoxysilane, stirring and mixing, adjusting the pH to 4-5 with glacial acetic acid, reacting, cooling, washing, and vacuum drying at 60° C. for 24 h to obtain epoxidized montmorillonite; S2, ultrasonically dispersing the epoxidized montmorillonite in N,N-dimethylformamide, adding aminopropyl di-terminated polydimethylsiloxane after the dispersion is uniform, stirring and mixing, reacting, and after the reaction is completed, centrifuging, washing, and vacuum drying at 80° C. for 12 h to obtain amino-modified montmorillonite; S3, ultrasonically dispersing the amino-modified montmorillonite in N,N-dimethylformamide, adding acryloyl chloride and triethylamine, stirring and mixing, reacting, and after the reaction is completed, filtering, washing, and drying at 60° C. for 24 hours to obtain olefinated montmorillonite; S4. Evenly mix deionized water, olefinated montmorillonite, acrylic acid, allyl polyethylene glycol, maleic anhydride, allyl polyoxyethylene ether, phenyl methacrylate, glycidyl methacrylate and initiator, heat up and react. After the reaction is completed, cool and adjust the pH with sodium hydroxide aqueous solution. The pH of the product is 7-8, and a sodium polycarboxylate dispersant for rubber is obtained.

2. The method for preparing a polycarboxylate sodium salt dispersant for rubber according to claim 1, characterized in that: In the step S1, the mass ratio of nano-montmorillonite, ethanol solution and γ-glycidyloxypropyltrimethoxysilane is 100:5800-7500:50-70, the reaction temperature is 75-90° C., and the reaction time is 2-5 hours.

3. The method for preparing a polycarboxylate sodium salt dispersant for rubber according to claim 1, characterized in that: In the step S2, the mass ratio of epoxidized montmorillonite, N,N-dimethylformamide, and aminopropyl di-terminated polydimethylsiloxane is 100:2100-2400:185-215.

4. The method for preparing a sodium polycarboxylate dispersant for rubber according to claim 1, characterized in that: The reaction temperature in step S2 is 60-70° C., and the reaction time is 4-6 hours.

5. The method for preparing a sodium polycarboxylate dispersant for rubber according to claim 1, characterized in that: In step S3, the mass ratio of amino-modified montmorillonite, N,N-dimethylformamide, acryloyl chloride and triethylamine is 100:1200-1500:58-75:30-50, the reaction temperature is 25-35° C., and the reaction time is 6-9 hours.

6. The method for preparing a sodium polycarboxylate dispersant for rubber according to claim 1, characterized in that: In the step S4, the mass ratio of deionized water, acrylic acid, olefinic montmorillonite, allyl polyethylene glycol, maleic anhydride, allyl polyoxyethylene ether, phenyl methacrylate, glycidyl methacrylate, and initiator is 600-750:100:3-5:120-150:24-35:8-14:7-10:4-7:5-12.

7. The method for preparing a polycarboxylate sodium salt dispersant for rubber according to claim 1, characterized in that: The reaction temperature in step S4 is 70-80° C., and the reaction time is 4-6 hours.

8. The method for preparing a polycarboxylate sodium salt dispersant for rubber according to claim 1, characterized in that: In step S4, the initiator is ammonium persulfate.

9. A sodium polycarboxylate dispersant for rubber prepared by the method for preparing a sodium polycarboxylate dispersant for rubber as claimed in any one of claims 1 to 8.

10. Use of the sodium polycarboxylate dispersant for rubber as claimed in claim 9 in rubber processing.

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