High-dispersity carbon black as well as preparation method and application thereof

Abstract

The invention discloses high-dispersity carbon black as well as a preparation method and application thereof, and relates to the technical field of carbon black modification, the high-dispersity carbon black comprises carbon black as well as a first adsorption layer, a second adsorption layer and a polymer coating layer which sequentially coat the surface of the carbon black; the first adsorption layer is prepared from sodium carboxymethyl cellulose, octadecyl dimethyl benzyl ammonium chloride and polyethylene glycol, the second adsorption layer is prepared from tannic acid and N-(beta-aminoethyl)-gamma-aminopropyl trimethoxy silane, and the polymer coating layer is a styrene-maleic anhydride copolymer. The prepared high-dispersity carbon black can be stably dispersed in absolute ethyl alcohol for a long time, and the comprehensive performance of a material can be effectively improved when the high-dispersity carbon black is added into a tire tread rubber composition.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon black modification, and in particular to a highly dispersed carbon black and a preparation method and application thereof. Background Art

[0002] As an indispensable reinforcing material in the rubber industry, carbon black plays a key role in improving the mechanical strength, wear resistance and electrical conductivity of tire tread rubber. Its reinforcing effect directly depends on the degree of dispersion in the rubber matrix. The size of native carbon black particles is usually less than 100 nanometers, with an extremely high specific surface area, resulting in strong van der Waals forces between particles, making irreversible agglomeration very likely to occur. High-structure carbon black has a complex branched aggregate morphology, which is conducive to building a conductive network, but it is more likely to form tight clumps, making further dispersion difficult. When the size of carbon black agglomerates in the tire tread rubber composition exceeds a certain value, it will significantly weaken the tensile strength and dynamic fatigue properties of the tread rubber and lead to uneven wear, which directly affects the safety and service life of the tire.

[0003] Currently, the main difficulties in dispersing carbon black are due to the following reasons: First, carbon black has poor compatibility with polar rubber matrices, resulting in weak interfacial bonding, which is particularly prone to phase separation in aqueous systems or high-humidity environments. Second, although the oxygen-containing functional groups such as hydroxyl and carboxyl groups formed on the carbon black surface during the preparation process have a certain degree of polarity, they quickly form an oxide layer after exposure to air, which further increases the surface energy of the carbon black and enhances the adsorption force between particles. Finally, the static charge accumulated by high-structure carbon black due to friction during the production process further exacerbates agglomeration through Coulomb attraction. For these reasons, it is difficult to achieve good dispersion of carbon black when it is added to the tire tread rubber composition and mixed, so that the carbon black cannot fully exert its reinforcing effect.

[0004] Various methods have been disclosed in the prior art to improve the dispersibility of carbon black. For example, ball milling or ultrasonic treatment uses mechanical shear force or cavitation effect to break up carbon black agglomerates; although the dispersibility of the treated carbon black is improved to a certain extent, secondary agglomeration is prone to occur during storage or mixing. Another example is the adsorption of anionic surfactants or polymer dispersants on the surface of carbon black to reduce its interfacial energy. Although traditional dispersants can improve initial dispersion, they are prone to thermal decomposition or migration and precipitation at high temperatures during rubber vulcanization, resulting in a sudden drop in the dispersion stability of carbon black, which directly affects the aging resistance and dynamic properties of the tread rubber. Another example is the use of silane coupling agents to modify carbon black, and the interaction of sulfanyl groups with carbon black to improve compatibility with rubber. However, when a large amount of carbon black is added, obvious agglomeration will still occur, affecting the performance of the tire tread rubber. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: to address the deficiencies in the existing technology, to provide a highly dispersible carbon black and its preparation method and application, wherein the highly dispersible carbon black can be stably dispersed for a long time in anhydrous ethanol, and can be added to a tire tread rubber composition to effectively improve the comprehensive performance of the material.

[0006] In the first aspect, in order to solve the above technical problems, the technical solution of the present invention is: A highly dispersible carbon black comprises carbon black and a first adsorption layer, a second adsorption layer and a polymer coating layer sequentially coated on the surface of the carbon black; the first adsorption layer is made of sodium carboxymethyl cellulose, octadecyldimethylbenzyl ammonium chloride and polyethylene glycol; the second adsorption layer is made of tannic acid and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane; and the polymer coating layer is a styrene-maleic anhydride copolymer.

[0007] In a second aspect, the present invention provides a method for preparing highly dispersible carbon black, comprising the following steps: (1) Activating carbon black to obtain pretreated carbon black; (2) Dispersing the pretreated carbon black in deionized water to obtain a pretreated carbon black aqueous dispersion, adding octadecyl dimethyl benzyl ammonium chloride to the pretreated carbon black aqueous dispersion, adjusting the pH of the system after ultrasonic dispersion, and performing a stirring adsorption treatment; cooling after the adsorption is completed, slowly adding polyethylene glycol under stirring, and performing a second stirring adsorption treatment after the addition is completed; then adding sodium carboxymethyl cellulose, adjusting the pH of the system, and heating to perform a third stirring adsorption treatment; after the treatment is completed, filtering the reaction solution, and drying the filtered precipitate to obtain a modified carbon black; (3) Mix tannic acid and ethanol solution, heat and stir until the solid is dissolved, adjust the pH of the system, slowly add N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane while stirring vigorously, and stir to react after the addition is completed; cool to room temperature after the reaction is completed to obtain a modified liquid; add the primary modified carbon black to the modified liquid, ultrasonically disperse, adjust the pH of the system, heat and react, filter the reaction liquid after the reaction is completed, wash the filtered precipitate, and dry it to obtain a secondary modified carbon black; (4) Dissolve styrene-maleic anhydride copolymer in DMF, add secondary modified carbon black, and perform ultrasonic treatment. Then, heat up and stir the mixture under an inert atmosphere to react. After the reaction is completed, cool to room temperature and filter the reaction system. The filtered precipitate is washed and dried to obtain highly dispersed carbon black.

[0008] Preferably, in step (1), the activation treatment process is as follows: in an inert atmosphere, carbon black is mixed with a nitric acid solution, heated and stirred, cooled to room temperature after the treatment, filtered, the precipitate is washed with water until neutral, and then dried to obtain pretreated carbon black.

[0009] Preferably, the temperature of the heating and stirring treatment is 90-100° C., the stirring speed is 500-800 rpm, and the time is 24-36 hours.

[0010] Preferably, the concentration of the nitric acid solution is 50-65 wt %, and the ratio of the carbon black to the nitric acid solution is 2 g: (8-15) ml.

[0011] Preferably, in step (2), the pH of the system is adjusted to 6.0-7.0 after adding octadecyldimethylbenzyl ammonium chloride; and the pH of the system is adjusted to 7.5 after adding sodium carboxymethyl cellulose.

[0012] Preferably, in step (2), the concentration of the pretreated carbon black aqueous dispersion is 0.8-1.5 g / L, the concentration of octadecyldimethylbenzyl ammonium chloride in the system is 0.2-0.3 mmol / L, the power of ultrasonic dispersion is 100 W, and the time is 20-30 min; the temperature of the stirring adsorption treatment is 38-42 ° C, the time is 1 h, and the stirring speed is 300 rpm.

[0013] Preferably, in step (2), the polyethylene glycol is polyethylene glycol 400, the amount of polyethylene glycol added is 0.5-1.5wt% of the mass of the pretreated carbon black, the temperature of the secondary stirring adsorption treatment is 28-32°C, the time is 40-50min, and the stirring speed is 200rpm.

[0014] Preferably, in step (2), the amount of sodium carboxymethyl cellulose added is 13-18 wt% of the mass of the pretreated carbon black; the temperature of the three stirring adsorption treatments is 45-55°C, the time is 60-90 min, and the stirring speed is 200-300 rpm.

[0015] Preferably, in step (3), the concentration of the ethanol solution is 45-50 v / v%, the mass ratio of tannic acid to N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane is (1-2):1; the stirring reaction temperature is 50-60°C, and the time is 2-4 hours.

[0016] Preferably, in step (3), after dissolving the tannic acid and adding the modified carbon black for ultrasonic dispersion, the pH of the system is adjusted to 5.0-6.0, the power of ultrasonic dispersion is 200-500 W, and the time is 15-30 min.

[0017] Preferably, in step (3), the mass ratio of the primary modified carbon black to tannic acid is 1:(0.2-1.0), the temperature of the temperature-raising reaction is 60-80°C, and the time is 4-8 hours.

[0018] Preferably, in step (4), the mass ratio of the secondary modified carbon black to the styrene-maleic anhydride copolymer is 1:(0.5-5); the ultrasonic treatment power is 200-300 W, the time is 30-60 min, the reaction temperature is 110-130 ° C, and the reaction time is 12-48 h.

[0019] The invention also discloses the application of high-dispersibility carbon black in tire tread rubber.

[0020] Due to the adoption of the above technical solution, the present invention has at least the following beneficial effects: The present invention provides a highly dispersible carbon black. A first adsorption layer, a second adsorption layer, and a polymer coating layer are sequentially disposed on the carbon black surface, forming a multilayer coating structure with complementary functions. The first adsorption layer is composed of octadecyldimethylbenzyl ammonium chloride, polyethylene glycol, and sodium carboxymethyl cellulose. The sodium carboxymethyl cellulose provides steric hindrance, the octadecyldimethylbenzyl chloride imparts hydrophobicity, and the polyethylene glycol enhances lubricity. These three layers synergistically improve the carbon black's dispersibility, facilitating subsequent modification. The second adsorption layer is composed of a complex of tannic acid and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane. Tannic acid is rich in phenolic hydroxyl groups, which provide strong adsorption sites and reactive points. The amino group of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane can react with tannic acid. At the same time, its methoxy group, after hydrolysis, can react with the active groups in the first adsorption layer on the carbon black surface to form a strong chemical bond, further improving the stability of the coating layer and facilitating subsequent polymer coating. The anhydride groups of the polymer coating layer can undergo a ring-opening reaction with the amino groups in the second adsorption layer to form an amide bond, achieving strong chemical bonding. In addition, the high molecular chain of the styrene-maleic anhydride copolymer can provide a strong steric hindrance effect, ensuring the long-term dispersion stability of the highly dispersed carbon black.

[0021] Traditional carbon black easily agglomerates in the rubber matrix, forming stress concentration points. The highly dispersed carbon black prepared by the present invention provides strong steric hindrance due to its multi-layer coating structure on the surface, especially the outermost styrene-maleic anhydride copolymer polymer layer. Moreover, the multi-layer coating structure on the surface of the carbon black contains abundant active groups. These active groups can produce strong physical adsorption and chemical interaction with the rubber molecular chains, thereby improving the good compatibility between the carbon black and the rubber matrix, so that it can be highly uniformly and stably dispersed in the rubber matrix during the mixing and vulcanization process, eliminating the stress concentration points caused by carbon black agglomeration, and effectively improving the tensile properties of the tire tread rubber composition. In addition, the good dispersion of the highly dispersed carbon black in the tire tread rubber and the strong interface bonding between it and the rubber matrix greatly improve the ability of the tire tread rubber composition to resist friction and mechanical damage; and the evenly dispersed carbon black particles can form a stronger "skeleton", effectively hindering the invasion of abrasive particles and the expansion of cracks, thereby improving the wear resistance of the material.

[0022] The second adsorption layer of the highly dispersible carbon black produced by the present invention includes tannic acid, a potent natural polyphenol antioxidant. Its molecule contains multiple ortho-phenolic hydroxyl groups, which effectively capture free radicals generated during the thermal oxidative aging process of rubber, thereby interrupting the free radical chain reaction and improving the tire tread's resistance to hot air aging. Furthermore, the multi-layered coating structure on the surface of the highly dispersible carbon black forms a physical barrier around the carbon black particles, effectively hindering the diffusion and penetration of oxygen into the rubber matrix. This significantly slows the oxidative degradation of rubber in thermal oxidative environments, allowing the tire tread to maintain its overall performance even in high-temperature environments.

[0023] The highly dispersible carbon black of the present invention achieves high dispersion within the rubber matrix and exhibits excellent interfacial bonding with the rubber matrix, significantly reducing stress concentration points. Furthermore, the coating layer on the surface of the highly dispersible carbon black, containing flexible components such as polyethylene glycol and long chains of styrene-maleic anhydride copolymer, facilitates uniform stress transmission and faster stress relaxation, enabling the resulting tire tread rubber composition to maintain good flexibility and elasticity even in low-temperature environments. DETAILED DESCRIPTION

[0024] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the solutions of the present invention will be further described below. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein can be combined with each other.

[0025] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all the embodiments.

[0026] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0027] The performance parameters or sources of some raw materials in the examples and comparative examples of the present invention are as follows: Carbon black: carbon black N330, Jiangxi Black Cat Carbon Black Co., Ltd. Styrene-maleic anhydride copolymer: Mn=2000, anhydride content 29%; Natural rubber: STR20, Sri Trang Rubber Co., Ltd., Thailand; Solution-polymerized styrene-butadiene rubber: BUNA VSL 4526-2 HM, Mooney viscosity (ML, 100°C, 3+4) 62.5, Lanxess Chemical (Shanghai) Co., Ltd. Butadiene rubber: brand BR9000, Mooney viscosity (ML, 100℃, 3+4) is 42.0, Shandong Qilu Petrochemical Engineering Co., Ltd. Microcrystalline wax: Shandong Yanggu Huatai Chemical Co., Ltd. Environmentally friendly aromatic oil TDAE: brand V500, a product of Germany's Hansheng Company; Sulfur: Wuxi Huasheng Rubber New Materials Technology Co., Ltd.

[0028] Unless otherwise specified, other raw materials are commercially available products, and the conditions described are conventional conditions in the art unless otherwise specified. Example 1

[0029] A method for preparing highly dispersible carbon black comprises the following steps: (1) Under an inert atmosphere, 4 g of carbon black was mixed with 16 ml of a 50 wt% nitric acid solution, heated to 90 °C, and stirred at 500 rpm for 24 h. After the treatment, the mixture was cooled to room temperature, filtered, and the precipitate was washed with water until neutral, and then vacuum-dried at 50 °C to obtain the pretreated carbon black. (2) Disperse the pretreated carbon black in deionized water to obtain a pretreated carbon black aqueous dispersion with a concentration of 0.8 g / L. Add octadecyl dimethyl benzyl ammonium chloride (the concentration of octadecyl dimethyl benzyl ammonium chloride in the system is 0.2 mmol / L) to 1 L of the pretreated carbon black aqueous dispersion with a concentration of 0.8 g / L. Ultrasonic dispersion is performed at a power of 100 W for 20 min. The pH of the system is adjusted to 6.0. Stir and adsorb for 1 h at 38 ° C and 300 rpm. After the adsorption is completed, cool. Polyethylene glycol 400 (the addition amount is 0.5wt% of the mass of the pretreated carbon black) is slowly added under stirring conditions of 200rpm. After the dropwise addition is completed, a second stirring adsorption treatment is carried out at 28°C and 200rpm for 50min. Then, sodium carboxymethyl cellulose (the addition amount is 13wt% of the mass of the pretreated carbon black) is added, the pH of the system is adjusted to 7.5, the temperature is raised to 45°C, and the adsorption treatment is carried out three times at a speed of 200rpm for 90min. After the treatment, the reaction solution is filtered, and the filtered precipitate is dried to obtain a primary modified carbon black. (3) Mix 1g of tannic acid and 80ml of 45v / v% ethanol solution, heat to 50℃, stir until the solid is dissolved, adjust the pH of the system to 5.0, add 1g of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane under vigorous stirring, and stir and react at 50℃ for 4h after the addition is completed; after the reaction is completed, cool to room temperature to obtain a modified liquid; add primary modified carbon black (the mass ratio of primary modified carbon black to tannic acid is 1:0.2) to the modified liquid, ultrasonically disperse at 200W for 30min, adjust the pH of the system to 6.0, heat to 60℃, and react for 8h. After the reaction is completed, filter the reaction liquid, wash the filtered precipitate, and dry it to obtain a secondary modified carbon black; (4) Dissolve 0.5 g of styrene-maleic anhydride copolymer in 500 ml of DMF, add 1 g of secondary modified carbon black, and ultrasonically treat at 200 W for 60 min. Then heat to 110 ° C and stir under an inert atmosphere for 48 h. After the reaction is completed, cool to room temperature, filter the reaction system, wash the filtered precipitate, and dry it to obtain highly dispersed carbon black. Example 2

[0030] A method for preparing highly dispersible carbon black comprises the following steps: (1) Under an inert atmosphere, 4 g of carbon black was mixed with 20 ml of a 55 wt% nitric acid solution, heated to 95 °C, and stirred at 600 rpm for 30 h. After the treatment, the mixture was cooled to room temperature, filtered, and the precipitate was washed with water until neutral, and then vacuum-dried at 50 °C to obtain the pretreated carbon black. (2) Disperse the pretreated carbon black in deionized water to obtain a pretreated carbon black aqueous dispersion with a concentration of 0.8 g / L. Add octadecyl dimethyl benzyl ammonium chloride (the concentration of octadecyl dimethyl benzyl ammonium chloride in the system is 0.25 mmol / L) to 1 L of the pretreated carbon black aqueous dispersion with a concentration of 1.0 g / L. Ultrasonic dispersion is performed at a power of 100 W for 25 min. The pH of the system is adjusted to 7.0. Stir and adsorb for 1 h at 40 ° C and 300 rpm. After the adsorption is completed, cool. Polyethylene glycol 400 (the addition amount is 1.0 wt% of the mass of the pretreated carbon black) is slowly added under stirring conditions of 200 rpm. After the dropwise addition is completed, a second stirring adsorption treatment is carried out at 30°C and 200 rpm for 45 minutes. Then, sodium carboxymethyl cellulose (the addition amount is 15 wt% of the mass of the pretreated carbon black) is added, the pH of the system is adjusted to 7.5, the temperature is raised to 50°C, and the adsorption treatment is carried out three times at a speed of 200 rpm for 80 minutes. After the treatment is completed, the reaction solution is filtered, and the filtered precipitate is dried to obtain a primary modified carbon black. (3) Mix 1.5 g of tannic acid and 80 ml of 45 v / v% ethanol solution, heat to 55 ° C, stir until the solid is dissolved, adjust the pH of the system to 6.0, add 1 g of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane under vigorous stirring, and stir and react at 55 ° C for 3 h; after the reaction is completed, cool to room temperature to obtain a modified solution; add primary modified carbon black (the mass ratio of primary modified carbon black to tannic acid is 1:0.2-1.0) to the modified solution, ultrasonically disperse at 300 W for 20 min, adjust the pH of the system to 6.0, heat to 70 ° C, and react for 6 h. After the reaction is completed, filter the reaction solution, wash the filtered precipitate, and dry it to obtain a secondary modified carbon black; (4) Dissolve 2 g of styrene-maleic anhydride copolymer in 500 ml of DMF, add 1 g of secondary modified carbon black, and ultrasonically treat at 300 W for 40 min. Then heat to 120 ° C and stir under an inert atmosphere for 24 h. After the reaction is completed, cool to room temperature, filter the reaction system, wash the filtered precipitate, and dry it to obtain highly dispersed carbon black. Example 3

[0031] A method for preparing highly dispersible carbon black comprises the following steps: (1) Under an inert atmosphere, 4 g of carbon black was mixed with 30 ml of a 65 wt% nitric acid solution, heated to 100 °C, and stirred at 800 rpm for 24 h. After the treatment, the mixture was cooled to room temperature, filtered, and the precipitate was washed with water until neutral, and then vacuum-dried at 50 °C to obtain the pretreated carbon black. (2) Disperse the pretreated carbon black in deionized water to obtain a pretreated carbon black aqueous dispersion with a concentration of 0.8 g / L. Add octadecyl dimethyl benzyl ammonium chloride (the concentration of octadecyl dimethyl benzyl ammonium chloride in the system is 0.3 mmol / L) to 1 L of the pretreated carbon black aqueous dispersion with a concentration of 1.5 g / L. Ultrasonic dispersion is performed at a power of 100 W for 30 min. The pH of the system is adjusted to 7.0. Stir and adsorb for 1 h at 42 ° C and 300 rpm. After the adsorption is completed, cool. Polyethylene glycol 400 (the addition amount is 1.5 wt% of the mass of the pretreated carbon black) is slowly added under stirring conditions of 200 rpm. After the dropwise addition is completed, a second stirring adsorption treatment is carried out at 32° C. and 200 rpm for 50 min. Then, sodium carboxymethyl cellulose (the addition amount is 18 wt% of the mass of the pretreated carbon black) is added, the pH of the system is adjusted to 7.5, the temperature is raised to 55° C., and the adsorption treatment is carried out three times at a speed of 300 rpm for 90 min. After the treatment, the reaction solution is filtered, and the filtered precipitate is dried to obtain a primary modified carbon black. (3) Mix 2g of tannic acid and 80ml of 50v / v% ethanol solution, heat to 60℃, stir until the solid is dissolved, adjust the pH of the system to 6.0, add 1g of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane under vigorous stirring, and stir and react at 60℃ for 4h after the addition is completed; after the reaction is completed, cool to room temperature to obtain a modified liquid; add primary modified carbon black (the mass ratio of primary modified carbon black to tannic acid is 1:1.0) to the modified liquid, ultrasonically disperse at 500W for 30min, adjust the pH of the system to 6.0, heat to 80℃, and react for 8h. After the reaction is completed, filter the reaction liquid, wash the filtered precipitate, and dry it to obtain a secondary modified carbon black; (4) Dissolve 5 g of styrene-maleic anhydride copolymer in 500 ml of DMF, add 1 g of secondary modified carbon black, and ultrasonically treat at 300 W for 60 min. Then heat to 130 ° C and stir under an inert atmosphere for 48 h. After the reaction is completed, cool to room temperature, filter the reaction system, wash the filtered precipitate, and dry it to obtain highly dispersed carbon black.

[0032] In order to verify the dispersibility of the highly dispersible carbon black prepared in the present invention in anhydrous ethanol, a detailed description is given below in conjunction with a plurality of comparative examples.

[0033] Comparative Example 1 The difference between this comparative example and Example 3 is that in step (2), the step of using octadecyldimethylbenzylammonium chloride for adsorption treatment is not included, and the other operations are the same as those in Example 3.

[0034] Comparative Example 2 The difference between this comparative example and Example 3 is that in step (2), the step of using polyethylene glycol 400 for adsorption treatment is not included, and the other operations are the same as those in Example 3.

[0035] Comparative Example 3 The difference between this comparative example and Example 3 is that in step (2), the step of using sodium carboxymethyl cellulose for adsorption treatment is not included, and the other operations are the same as in Example 3.

[0036] Comparative Example 4 The difference between this comparative example and Example 3 is that the specific process of step (3) is as follows: 2 g of tannic acid and 80 ml of 50 v / v% ethanol solution are mixed, the temperature is raised to 60°C, and the mixture is stirred until the solid is dissolved. The primary modified carbon black (the mass ratio of the primary modified carbon black to tannic acid is 1:1.0) is added, and ultrasonic dispersion is performed at 500W for 30 minutes. The pH of the system is adjusted to 6.0, the temperature is raised to 80°C, and the reaction is carried out for 8 hours. After the reaction is completed, the reaction solution is filtered, the filtered precipitate is washed, and then dried to obtain the secondary modified carbon black. The other steps are the same as those in Example 3.

[0037] Comparative Example 5 The difference between this comparative example and Example 3 is that the specific process of step (3) is as follows: 1 g of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane and 80 ml of 50 v / v% ethanol solution are mixed, the temperature is raised to 60°C, the pH of the system is adjusted to 6.0, and the reaction is stirred at 60°C for 4 hours; after the reaction is completed, the mixture is cooled to room temperature to obtain a modified liquid; the primary modified carbon black (the mass ratio of the primary modified carbon black to tannic acid is 1:1.0) is added to the modified liquid, ultrasonically dispersed at 500W for 30 minutes, the pH of the system is adjusted to 6.0, the temperature is raised to 80°C, and the reaction is carried out for 8 hours. After the reaction is completed, the reaction liquid is filtered, the filtered precipitate is washed, and dried to obtain a secondary modified carbon black. The other steps are the same as those in Example 3.

[0038] Comparative Example 6 The difference between this comparative example and Example 3 is that step (2) is not included, and the other operations are the same as those in Example 3.

[0039] Comparative Example 7 The difference between this comparative example and Example 3 is that step (3) is not included, and other operations are the same as those in Example 3.

[0040] Comparative Example 8 The difference between this comparative example and Example 3 is that step (4) is not included, and the other operations are the same as those in Example 3.

[0041] 1 g of the highly dispersible carbon black prepared in the above examples and comparative examples was respectively mixed with 50 ml of anhydrous ethanol and ultrasonically dispersed at a power of 500 W for 30 min to obtain different dispersions. The above dispersions were placed at room temperature for 120 days. During this period, the state of the dispersions was observed every day to visually observe whether there was any precipitation. The test results are shown in Table 1.

[0042] Table 1

[0043] As can be seen from the test results in Table 1, in Examples 1-3, carbon black was subjected to pretreatment, primary modification, secondary modification, and polymer coating, respectively, to form multiple modified layers on the carbon black surface. The resulting highly dispersible carbon black dispersed well in anhydrous ethanol and showed no precipitation after 120 days at room temperature. However, in Comparative Examples 1-8, which lacked the key modification steps, the resulting highly dispersible carbon black exhibited reduced dispersibility.

[0044] Specifically, during the preparation of the first adsorption layer, octadecyldimethylbenzyl ammonium chloride (DBMC) serves as a cationic surfactant, initially reducing the surface energy of the pretreated carbon black through electrostatic adsorption. Polyethylene glycol 400 (PEG-400) acts as a nonionic surfactant, providing steric hindrance. Sodium carboxymethyl cellulose (SCMC) acts as an anionic surfactant, enhancing electrostatic repulsion. These three surfactants synergistically form the first adsorption layer on the carbon black surface, significantly improving the dispersibility of the highly dispersible carbon black through a dual "electrostatic-steric" stabilization mechanism. In Comparative Examples 1-3, which lack adsorption treatment with octadecyldimethylbenzyl ammonium chloride, PEG-400, or SCMC, the resulting highly dispersible carbon black exhibited significantly reduced dispersion in anhydrous ethanol.

[0045] When preparing the second adsorption layer, the present invention uses a complex of tannic acid and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane as a modifier. The phenolic hydroxyl groups in the tannic acid provide a large number of reaction sites, which react with the amino groups of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane to form a covalently linked TA-N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane complex. The silanol formed by the hydrolysis of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane can undergo a condensation reaction with the carboxyl active groups on the surface of the primary modified carbon black to form Si-OC covalent bonds, anchoring the second adsorption layer to the surface of the primary modified carbon black, forming a three-dimensional cross-linked structure of "carbon black-tannic acid-N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane", which greatly enhances the dispersibility of the highly dispersible carbon black in anhydrous ethanol. Comparative Example 4 lacks N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, and Comparative Example 5 lacks tannic acid, so the dispersibility of the highly dispersible carbon black obtained is reduced to a certain extent.

[0046] When treating carbon black, the carbon black is first modified with octadecyldimethylbenzyl ammonium chloride, polyethylene glycol, and sodium carboxymethyl cellulose to achieve initial dispersion of the carbon black. Tannic acid and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane are then used for secondary modification to enhance the interfacial bonding between the modified layer and the carbon black. Finally, polymer coating is used as a tertiary modification to ensure the dispersion stability of the carbon black. The three modification methods described above work together to enable long-term dispersion of highly dispersible carbon black in an anhydrous ethanol matrix. Comparative Examples 6-8 lack any of the modification methods, and the dispersibility of the highly dispersible carbon black decreases to a certain extent.

[0047] Application Example 1 A method for preparing a tire tread rubber composition containing highly dispersible carbon black comprises the following steps: S1, the internal mixer is preheated to 50 ℃, 55 parts of natural rubber, 23 parts of solution polymerized styrene-butadiene rubber, 12 parts of butadiene rubber are dropped into, and mixing is carried out at 50rpm for 60 seconds until the raw rubber roll is even, and 8 parts of high-dispersibility carbon black, 3 parts of zinc oxide, 2 parts of stearic acid, 2.0 parts of antioxidant 4020, 1.0 part of antioxidant RD, 1.2 parts of microcrystalline wax are added to the internal mixer in sequence, and the temperature is raised to 145 ℃ at 80rpm, and the remaining 8 parts of high-dispersibility carbon black and 13 parts of environment-friendly aromatic oil TDAE are added. Mixing is continued until the temperature reaches 145 ℃ again, and the glue is discharged to the open mixer, and thinned 4 times at 60 ℃, and triangle bagged, and sheeted to obtain a masterbatch; S2. After the masterbatch is left for 24 hours, it is put into an internal mixer preheated to 50°C and mixed at 40 rpm for 1 minute to soften the masterbatch evenly. 1.5 parts of sulfur, 0.4 parts of accelerator D and 1.3 parts of accelerator CZ are added and mixed at 50 rpm for 2 minutes. The masterbatch is discharged into an open mixer with a roller temperature of 50°C, thinned 5 times, triangularly packaged, and unrolled. During the discharge process, the discharge temperature must be strictly controlled below 108°C to obtain a tire tread rubber composition.

[0048] Application Example 2 The difference from Application Example 1 is that an equal amount of the highly dispersed carbon black of Example 2 is used to replace the highly dispersed carbon black of Example 1, and other operations are the same as those of Application Example 1.

[0049] Application Example 3 The difference from Application Example 1 is that an equal amount of the highly dispersed carbon black of Example 3 is used to replace the highly dispersed carbon black of Example 1, and other operations are the same as those of Application Example 1.

[0050] Comparative Application Example 1 The difference from Application Example 1 is that an equal amount of the highly dispersed carbon black of Comparative Example 1 is used to replace the highly dispersed carbon black of Example 1, and other operations are the same as those of Application Example 1.

[0051] Application Comparative Example 2 The difference from Application Example 1 is that an equal amount of the highly dispersed carbon black of Comparative Example 2 is used to replace the highly dispersed carbon black of Example 1, and other operations are the same as those of Application Example 1.

[0052] Application Comparative Example 3 The difference from Application Example 1 is that an equal amount of the highly dispersed carbon black of Comparative Example 3 is used to replace the highly dispersed carbon black of Example 1, and other operations are the same as those of Application Example 1.

[0053] Comparative Application Example 4 The difference from Application Example 1 is that an equal amount of the highly dispersed carbon black of Comparative Example 4 is used to replace the highly dispersed carbon black of Example 1, and other operations are the same as those of Application Example 1.

[0054] Application Comparative Example 5 The difference from Application Example 1 is that an equal amount of the highly dispersed carbon black of Comparative Example 5 is used to replace the highly dispersed carbon black of Example 1, and other operations are the same as those of Application Example 1.

[0055] Application Comparative Example 6 The difference from Application Example 1 is that an equal amount of the highly dispersed carbon black of Comparative Example 6 is used to replace the highly dispersed carbon black of Example 1, and other operations are the same as those of Application Example 1.

[0056] Application Comparative Example 7 The difference from Application Example 1 is that an equal amount of the highly dispersed carbon black of Comparative Example 7 is used to replace the highly dispersed carbon black of Example 1, and other operations are the same as those of Application Example 1.

[0057] Comparative Application Example 8 The difference from Application Example 1 is that an equal amount of the highly dispersed carbon black of Comparative Example 8 is used to replace the highly dispersed carbon black of Example 1, and other operations are the same as those of Application Example 1.

[0058] The tire tread rubber compositions prepared in the above-mentioned application examples 1-3 and application comparative examples 1-8 were subjected to performance tests. The test methods and test results are as follows: 1. Mechanical properties test: The tensile strength and elongation at break tests were performed in accordance with GB / T528-2009.

[0059] 2. Wear resistance test: The wear resistance test was carried out in accordance with GB / T1689-1998 Determination of wear resistance of vulcanized rubber.

[0060] The above test results are shown in Table 2.

[0061] 3. Hot air aging performance test: The test samples were placed in a 401A aging chamber at 100°C for 48 h. The mechanical properties, wear resistance, and cutting loss rate of the aged samples were tested. The test results are shown in Table 3.

[0062] 4. Low temperature resistance test: The test samples were placed at -80°C for 7 days, and the mechanical properties, wear resistance, and cutting loss rate of the treated samples were tested. The test results are shown in Table 4.

[0063] Table 2 (unprocessed)

[0064] Table 3 (100℃×48h)

[0065] Table 4 (-80℃×7d)

[0066] It can be seen from Tables 2, 3 and 4 that the highly dispersed carbon black prepared in the present invention is applied to tire tread rubber, and the prepared composition not only has good tensile properties, but also excellent wear resistance, hot air aging resistance and low temperature resistance.

[0067] Compared with Examples 1-3, the highly dispersed carbon black prepared in Comparative Examples 1-8 lacks some modification steps, and when added to tire tread rubber, the comprehensive performance of the prepared composition is reduced.

[0068] Specifically, the preparation of the highly dispersible carbon black in Comparative Example 1 lacked adsorption treatment with octadecyldimethylbenzyl ammonium chloride, resulting in poor dispersion of the carbon black in the tire tread rubber and a significant decrease in the wear resistance of the composition. The highly dispersible carbon black in Comparative Example 2 lacked adsorption treatment with polyethylene glycol 400, leading to uneven mixing during the preparation of the tire tread rubber composition and a certain decrease in the elongation at break of the composition after low-temperature treatment. The highly dispersible carbon black in Comparative Example 3 lacked adsorption treatment with sodium carboxymethylcellulose, which weakened the steric hindrance and made it difficult for the highly dispersible carbon black to maintain long-term stability in the tire tread rubber. Consequently, the composition's resistance to hot air aging and low-temperature resistance significantly deteriorated.

[0069] Comparative Examples 4 and 5 lack modification with tannic acid or N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, which weakens the interfacial bonding between the carbon black and the modified layer, leading to a significant decrease in the tensile properties of the resulting tire tread rubber composition after aging. The highly dispersible carbon black in Comparative Example 6 lacks the first adsorption layer, resulting in poor initial dispersibility of the carbon black, affecting subsequent modification, and the most significant decrease in the overall performance of the tire tread rubber composition prepared therefrom. The highly dispersible carbon black in Comparative Example 7 lacks modification with tannic acid / N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, resulting in poor dispersion of the highly dispersible carbon black in the tire tread rubber matrix, more agglomerates, and thus increased local friction heat, and reduced wear resistance of the composition. The highly dispersible carbon black in Comparative Example 8 lacks the polymer coating step, which poorly bonds the highly dispersible carbon black to the tire tread rubber matrix, significantly reducing the wear resistance of the material.

[0070] Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas, including the best mode, and also enable any technician in the field to practice the present invention, including making and using any device or system, and implementing any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements similar to the literal description of the claims, or if they include equivalent structural elements that are not substantially different from the literal description of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. A highly dispersible carbon black, characterized by: The invention comprises carbon black and a first adsorption layer, a second adsorption layer and a polymer coating layer which are sequentially coated on the surface of the carbon black; the first adsorption layer is made of sodium carboxymethyl cellulose, octadecyldimethylbenzyl ammonium chloride and polyethylene glycol; the second adsorption layer is made of tannic acid and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane; and the polymer coating layer is a styrene-maleic anhydride copolymer.

2. The method for preparing highly dispersible carbon black according to claim 1, wherein: The following steps are involved: (1) Activating carbon black to obtain pretreated carbon black; (2) Dispersing the pretreated carbon black in deionized water to obtain a pretreated carbon black aqueous dispersion, adding octadecyldimethylbenzyl ammonium chloride to the pretreated carbon black aqueous dispersion, adjusting the pH of the system after ultrasonic dispersion, and performing a stirring adsorption treatment; After the adsorption is completed, cool down and add polyethylene glycol under stirring. After the addition is completed, perform a second stirring adsorption treatment; Then, sodium carboxymethyl cellulose is added to adjust the pH of the system, and the temperature is raised to perform stirring adsorption treatment three times; after the treatment, the reaction liquid is filtered, and the filtered precipitate is dried to obtain a primary modified carbon black; (3) Mix tannic acid and ethanol solution, heat and stir until the solid dissolves, adjust the pH of the system, slowly add N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane under vigorous stirring, and stir to react after the addition is completed; cool to room temperature after the reaction is completed to obtain a modified solution; Adding the primary modified carbon black to the modified liquid, ultrasonically dispersing, adjusting the pH of the system, heating the reaction, filtering the reaction liquid after the reaction is completed, washing the filtered precipitate, and drying to obtain the secondary modified carbon black; (4) Dissolve styrene-maleic anhydride copolymer in DMF, add secondary modified carbon black, and perform ultrasonic treatment. Then, heat up and stir the mixture under an inert atmosphere to react. After the reaction is completed, cool to room temperature and filter the reaction system. The filtered precipitate is washed and dried to obtain highly dispersed carbon black.

3. The method for preparing highly dispersible carbon black according to claim 2, wherein: In step (1), the activation treatment process is as follows: under an inert atmosphere, carbon black is mixed with a nitric acid solution with a concentration of 50-65wt%, the amount ratio of carbon black to nitric acid solution is controlled to be 2g: (8-15)ml, the temperature is raised to 90-100°C, and the stirring treatment is carried out at 500-800 rpm for 24-36h. After the treatment, the mixture is cooled to room temperature, filtered, the precipitate is washed with water until it is neutral, and then dried to obtain pretreated carbon black.

4. The method for preparing highly dispersible carbon black according to claim 2, wherein: In step (2), after adding octadecyl dimethyl benzyl ammonium chloride, the pH of the system is adjusted to 6.0-7.0; after adding sodium carboxymethyl cellulose, the pH of the system is adjusted to 7.5; the concentration of the pretreated carbon black aqueous dispersion is 0.8-1.5 g / L, the concentration of octadecyl dimethyl benzyl ammonium chloride in the system is 0.2-0.3 mmol / L, the power of ultrasonic dispersion is 100 W, and the time is 20-30 min; the temperature of the one-time stirring adsorption treatment is 38-42 ° C, the time is 1 hour, and the stirring speed is 300 rpm.

5. The method for preparing highly dispersible carbon black according to claim 2, wherein: In step (2), the polyethylene glycol is polyethylene glycol 400, and the amount of polyethylene glycol added is 0.5-1.5wt% of the mass of the pretreated carbon black. The temperature of the secondary stirring adsorption treatment is 28-32°C, the time is 40-50min, and the stirring speed is 200rpm.

6. The method for preparing highly dispersible carbon black according to claim 2, wherein: In step (2), the amount of sodium carboxymethyl cellulose added is 13-18 wt% of the mass of the pretreated carbon black; the temperature of the three stirring adsorption treatments is 45-55°C, the time is 60-90 min, and the stirring speed is 200-300 rpm.

7. The method for preparing highly dispersible carbon black according to claim 2, wherein: In step (3), the concentration of the ethanol solution is 45-50 v / v%, the mass ratio of tannic acid to N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane is (1-2):1; the stirring reaction temperature is 50-60°C, and the reaction time is 2-4 hours.

8. The method for preparing highly dispersible carbon black according to claim 2, wherein: In step (3), after dissolving the tannic acid and adding the first modified carbon black for ultrasonic dispersion, the pH of the system is adjusted to 5.0-6.0, the power of the ultrasonic dispersion is 200-500 W, and the time is 15-30 min; the mass ratio of the first modified carbon black to the tannic acid is 1: (0.2-1.0), the temperature of the temperature-raising reaction is 60-80 ° C, and the time is 4-8 h.

9. The method for preparing highly dispersible carbon black according to claim 2, wherein: In step (4), the mass ratio of the secondary modified carbon black to the styrene-maleic anhydride copolymer is 1:(0.5-5); the ultrasonic treatment power is 200-300 W, the time is 30-60 min, the reaction temperature is 110-130 ° C, and the reaction time is 12-48 h.

10. Use of the highly dispersed carbon black prepared according to the method according to any one of claims 2 to 9 in a tire tread rubber composition.

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