Highly dispersible carbon black, process for its preparation and use

Abstract

The application discloses high-dispersibility carbon black and a preparation method and application thereof, relates to the technical field of carbon black modification, and the high-dispersibility carbon black 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 prepared from sodium carboxymethylcellulose, octadecyl dimethyl benzyl ammonium chloride and polyethylene glycol; the second adsorption layer is prepared from tannic acid and N-(beta-aminoethyl)-gamma-aminopropyl trimethoxysilane; and the polymer coating layer is a styrene-maleic anhydride copolymer. The high-dispersibility carbon black prepared by the application can realize long-time stable dispersion in anhydrous ethanol, and can effectively improve the comprehensive performance of a material when added into a tire tread rubber composition.

Description

Technical Field

[0001] This invention relates to the field of carbon black modification technology, specifically to a highly dispersible carbon black, its preparation method, and its applications. Background Technology

[0002] Carbon black, an indispensable reinforcing material in the rubber industry, plays a crucial role in improving the mechanical strength, wear resistance, and electrical conductivity of tire tread compounds. Its reinforcing effect directly depends on its dispersion within the rubber matrix. Virgin carbon black particles are typically smaller than 100 nanometers, possessing an extremely high specific surface area, resulting in strong van der Waals forces between particles and making irreversible agglomeration highly likely. High-structure carbon black, with its complex branched aggregate morphology, while beneficial for building conductive networks, is more prone to forming dense agglomerates, making further dispersion difficult. When the carbon black agglomerate size in the tire tread compound exceeds a certain value, it significantly weakens the tensile strength and dynamic fatigue performance of the tread compound, leading to uneven wear and directly affecting tire safety and service life.

[0003] Currently, the dispersion challenges of carbon black mainly stem from the following factors: First, carbon black has poor compatibility with polar rubber matrices, resulting in weak interfacial bonding, which easily leads to phase separation, especially in aqueous systems or high-humidity environments. Second, the oxygen-containing functional groups such as hydroxyl and carboxyl groups formed on the carbon black surface during preparation, although possessing a certain degree of polarity, rapidly form an oxide layer upon exposure to air, further increasing the surface energy of the carbon black and enhancing interparticle adsorption. Finally, the static charge accumulated by triboelectric charging during the production of high-structure carbon black further intensifies agglomeration through Coulomb attraction. For these reasons, it is difficult to achieve good dispersion when carbon black is added to tire tread rubber compositions, preventing it from fully exerting its reinforcing effect.

[0004] Several methods have been disclosed in the prior art to improve the dispersibility of carbon black. For example, ball milling or ultrasonic treatment utilizes mechanical shearing force or cavitation effect to break up carbon black agglomerates. While the dispersibility of the treated carbon black is improved to some extent, secondary agglomeration is prone to occur during storage or mixing. Another method involves adsorbing anionic surfactants or polymeric dispersants onto the carbon black surface to reduce its interfacial energy. Although traditional dispersants can improve initial dispersion, they are prone to thermal decomposition or migration and precipitation at the high temperatures of rubber vulcanization, leading to a sharp drop in the dispersion stability of carbon black and directly affecting the aging resistance and dynamic performance of the tire tread compound. Yet another method involves modifying carbon black with silane coupling agents, improving compatibility with rubber through the interaction of thioalkyl groups. However, when a large amount of carbon black is added, significant agglomeration still occurs, affecting the performance of the tire tread compound. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a highly dispersible carbon black, its preparation method and application, which can achieve stable dispersion in anhydrous ethanol for a long time and can effectively improve the overall performance of the material when added to the tire tread rubber composition, in order to address the shortcomings of the existing technology.

[0006] Firstly, to solve the above-mentioned technical problems, the technical solution of the present invention is:

[0007] 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, octadecyl dimethyl benzyl 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.

[0008] Secondly, the present invention provides a method for preparing highly dispersible carbon black, comprising the following steps:

[0009] (1) The carbon black is activated to obtain pretreated carbon black;

[0010] (2) Disperse the pretreated carbon black in deionized water to obtain a pretreated carbon black aqueous dispersion. Add octadecyl dimethyl benzyl ammonium chloride to the pretreated carbon black aqueous dispersion, and adjust the pH of the system after ultrasonic dispersion. Perform a first stirring adsorption treatment. After the adsorption is completed, cool the system and slowly add polyethylene glycol under stirring. After the addition is completed, perform a second stirring adsorption treatment. Then add sodium carboxymethyl cellulose, adjust the pH of the system, and heat the system for a third stirring adsorption treatment. After the treatment is completed, filter the reaction solution, and dry the precipitate after filtration to obtain primary modified carbon black.

[0011] (3) Mix tannic acid and ethanol solution, heat and stir until the solid dissolves, adjust the pH of the system and slowly add N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane under vigorous stirring, and stir the reaction after the addition is complete; after the reaction is complete, cool to room temperature to obtain modified solution; add primary modified carbon black to modified solution, disperse by ultrasonication, adjust the pH of the system, heat the reaction, after the reaction is complete, filter the reaction solution, wash the precipitate after filtration and dry it to obtain secondary modified carbon black;

[0012] (4) The styrene-maleic anhydride copolymer was dissolved in DMF, and secondary modified carbon black was added. The mixture was ultrasonically treated, then heated and stirred under an inert atmosphere. After the reaction was completed, the mixture was cooled to room temperature, the reaction system was filtered, and the precipitate was washed and dried to obtain highly dispersed carbon black.

[0013] Preferably, in step (1), the activation process is as follows: under an inert atmosphere, carbon black is mixed with nitric acid solution, heated and stirred, cooled to room temperature after treatment, filtered, washed with precipitate water until neutral, and then dried to obtain pretreated carbon black.

[0014] Preferably, the temperature for the heating and stirring treatment is 90-100℃, the stirring speed is 500-800 rpm, and the time is 24-36 hours.

[0015] Preferably, the concentration of the nitric acid solution is 50-65 wt%, and the ratio of carbon black to nitric acid solution is 2 g: (8-15) ml.

[0016] Preferably, in step (2), the pH of the system is adjusted to 6.0-7.0 after adding octadecyl dimethyl benzyl ammonium chloride; and the pH of the system is adjusted to 7.5 after adding sodium carboxymethyl cellulose.

[0017] Preferably, in step (2), 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 ultrasonic dispersion power is 100 W, and the time is 20-30 min; the temperature of the first stirring adsorption treatment is 38-42℃, the time is 1 h, and the stirring speed is 300 rpm.

[0018] Preferably, in step (2), the polyethylene glycol is polyethylene glycol 400, the amount of polyethylene glycol added is 0.5-1.5 wt% of the pretreated carbon black, the temperature of the secondary stirring adsorption treatment is 28-32℃, the time is 40-50 min, and the stirring speed is 200 rpm.

[0019] Preferably, in step (2), the amount of sodium carboxymethyl cellulose added is 13-18 wt% of the pretreated carbon black; the temperature of the three-stage stirring adsorption treatment is 45-55℃, the time is 60-90 min, and the stirring speed is 200-300 rpm.

[0020] Preferably, in step (3), the concentration of the ethanol solution is 45-50 v / v%, and the mass ratio of the tannic acid to N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane is (1-2):1; the stirring reaction temperature is 50-60℃, and the time is 2-4h.

[0021] Preferably, in step (3), after dissolving tannic acid and adding modified carbon black for ultrasonic dispersion, the pH of the system is adjusted to 5.0-6.0, the ultrasonic dispersion power is 200-500W, and the time is 15-30min.

[0022] Preferably, in step (3), the mass ratio of primary modified carbon black to tannic acid is 1:(0.2-1.0), the temperature of the heating reaction is 60-80℃, and the time is 4-8h.

[0023] 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 200-300W, the time is 30-60min, the reaction temperature is 110-130℃, and the reaction time is 12-48h.

[0024] This invention also discloses the application of highly dispersible carbon black in tire tread compound.

[0025] By adopting the above technical solution, the present invention has at least the following beneficial effects:

[0026] This invention provides a highly dispersible carbon black by sequentially depositing a first adsorption layer, a second adsorption layer, and a polymer coating layer on the surface of the carbon black, forming a multi-layered coating structure with complementary functions. The first adsorption layer is composed of octadecyl dimethyl benzyl ammonium chloride, polyethylene glycol, and sodium carboxymethyl cellulose. Sodium carboxymethyl cellulose provides steric hindrance, octadecyl dimethyl benzyl chloride provides hydrophobicity, and polyethylene glycol improves lubricity. The three components synergistically improve the initial dispersibility of the carbon black, facilitating subsequent modification treatment of the carbon black. The second adsorption layer consists of a complex of tannic acid and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane. Tannic acid is rich in phenolic hydroxyl groups, providing strong adsorption sites and reactive sites. The amino group of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane can react with tannic acid, and its methoxy group, after hydrolysis, can react with the active groups in the first adsorption layer on the carbon black surface to form strong chemical bonds, further improving the stability of the coating layer and facilitating subsequent polymer coating. The anhydride groups of the polymer coating layer can undergo ring-opening reactions with the amino groups in the second adsorption layer to form amide bonds, achieving strong chemical bonds. Moreover, the polymer chain of the styrene-maleic anhydride copolymer can provide a strong steric hindrance effect, ensuring the long-term dispersion stability of the highly dispersible carbon black.

[0027] Traditional carbon black tends to agglomerate in rubber matrices, forming stress concentration points. The highly dispersible carbon black prepared in this invention, due to its multi-layered surface coating structure, especially the outermost styrene-maleic anhydride copolymer polymer layer, provides strong steric hindrance. Furthermore, the multi-layered coating structure contains abundant active groups, which can generate strong physical adsorption and chemical interactions with rubber molecular chains, improving the compatibility between carbon black and the rubber matrix. This allows for highly uniform and stable dispersion within the rubber matrix during mixing and vulcanization, eliminating stress concentration points caused by carbon black agglomeration and effectively improving the tensile properties of the tire tread compound composition. In addition, the excellent dispersion of the highly dispersible carbon black in the tire tread compound and the strong interfacial bonding with the rubber matrix significantly enhance the tire tread compound composition's resistance to friction and mechanical damage. Moreover, the uniformly dispersed carbon black particles can form a more robust "skeleton," effectively hindering the penetration of abrasive particles and the propagation of cracks, thereby improving the material's wear resistance.

[0028] The second adsorption layer of the highly dispersible carbon black prepared by this invention includes tannic acid, a potent natural polyphenol antioxidant. Its molecule contains multiple ortho-phenolic hydroxyl groups, which can effectively capture free radicals generated during the thermo-oxidative aging process of rubber, thereby interrupting the free radical chain reaction and improving the heat and air aging resistance of the tire tread compound. Furthermore, the multi-layer coating structure on the surface of the highly dispersible carbon black forms a physical barrier around the carbon black particles, effectively preventing oxygen from diffusing and penetrating into the rubber matrix, significantly slowing down the oxidative degradation rate of rubber under thermo-oxidative conditions, allowing the tire tread compound to maintain its overall performance well under high-temperature environments.

[0029] The highly dispersible carbon black of this invention achieves high dispersion in a rubber matrix and exhibits good interfacial bonding with the rubber matrix, significantly reducing stress concentration points. Simultaneously, the coating layer on the surface of the highly dispersible carbon black contains flexible components such as long-chain polyethylene glycol and styrene-maleic anhydride copolymer, which facilitates uniform stress transfer and faster stress relaxation. This allows the resulting tire tread compound composition to maintain good flexibility and elasticity at low temperatures. Detailed Implementation

[0030] To better understand the above-mentioned objectives, features, and advantages of the present invention, the solutions of the present invention will be further described below. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

[0031] Many specific details are set forth in the following description in order to provide a full understanding of the invention, but the invention may also be practiced in other ways different from those described herein; obviously, the embodiments in the specification are only some embodiments of the invention, and not all embodiments.

[0032] 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, and not for limiting the scope of the claims of the present invention.

[0033] The following are some of the raw material performance parameters or sources used in the embodiments and comparative examples of this invention:

[0034] Carbon black: Carbon black N330, Jiangxi Black Cat Carbon Black Co., Ltd.;

[0035] Styrene-maleic anhydride copolymer: Mn=2000, anhydride content 29%;

[0036] Natural rubber: STR20, Sittang Rubber Co., Ltd., Thailand;

[0037] Solution-polymerized styrene-butadiene rubber: Grade BUNA VSL 4526-2 HM, Mooney viscosity (ML, 100℃, 3+4) is 62.5, Lanxess Chemicals (Shanghai) Co., Ltd.;

[0038] Butadiene rubber: Grade BR9000, Mooney viscosity (ML, 100℃, 3+4) is 42.0, Shandong Qilu Petrochemical Engineering Co., Ltd.;

[0039] Microcrystalline wax: Shandong Yanggu Huatai Chemical Co., Ltd.;

[0040] Environmentally friendly aromatic oil TDAE: Grade V500, a product of German company Hansheng;

[0041] Sulfur: Wuxi Huasheng Rubber New Material Technology Co., Ltd.

[0042] Unless otherwise specified, all other raw materials are commercially available products, and the conditions described are standard conditions in the field. Example 1

[0043] A method for preparing highly dispersible carbon black includes the following steps:

[0044] (1) Under an inert atmosphere, 4g of carbon black was mixed with 16ml of 50wt% nitric acid solution, heated to 90℃, and stirred at 500 rpm for 24h. After treatment, the mixture was cooled to room temperature, filtered, and the precipitate was washed with water until neutral. Then, it was dried under vacuum at 50℃ to obtain pretreated carbon black.

[0045] (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. Sonicate the dispersion at 100 W for 20 min, adjust the pH of the system to 6.0, and perform adsorption treatment by stirring once at 38℃ and 300 rpm for 1 h. After the adsorption is completed, cool the system. Polyethylene glycol 400 (0.5 wt% of the pretreated carbon black mass) was slowly added under stirring at 200 rpm. After the addition was completed, the mixture was stirred and adsorbed for 50 min at 28℃ and 200 rpm. Then, sodium carboxymethyl cellulose (13 wt% of the pretreated carbon black mass) was added, the pH of the system was adjusted to 7.5, the temperature was raised to 45℃, and the mixture was stirred and adsorbed for 90 min at 200 rpm for three times. After the treatment, the reaction solution was filtered, the precipitate was dried, and primary modified carbon black was obtained.

[0046] (3) Mix 1g of tannic acid and 80ml of 45v / v% ethanol solution, heat to 50℃, stir until the solid dissolves, adjust the pH of the system to 5.0, add 1g of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane under vigorous stirring, and stir at 50℃ for 4h after the addition is complete; after the reaction is complete, cool to room temperature to obtain modified solution; add primary modified carbon black (mass ratio of primary modified carbon black to tannic acid is 1:0.2) to the modified solution, ultrasonically disperse at 200W for 30min, adjust the pH of the system to 6.0, heat to 60℃, react for 8h, after the reaction is complete, filter the reaction solution, wash the precipitate after filtration, and dry to obtain secondary modified carbon black;

[0047] (4) Dissolve 0.5g of styrene-maleic anhydride copolymer in 500ml of DMF, add 1g of secondary modified carbon black, sonicate at 200W for 60min, then heat to 110℃, stir and react for 48h under an inert atmosphere. After the reaction is completed, cool to room temperature, filter the reaction system, wash the precipitate after filtration and dry it to obtain highly dispersible carbon black. Example 2

[0048] A method for preparing highly dispersible carbon black includes the following steps:

[0049] (1) Under an inert atmosphere, 4g of carbon black was mixed with 20ml of 55wt% nitric acid solution, heated to 95℃, and stirred at 600 rpm for 30h. After treatment, the mixture was cooled to room temperature, filtered, and the precipitate was washed with water until neutral. Then, it was dried under vacuum at 50℃ to obtain pretreated carbon black.

[0050] (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. Sonicate the dispersion at 100 W for 25 min, adjust the pH of the system to 7.0, and perform adsorption treatment by stirring once at 40℃ and 300 rpm for 1 h. After the adsorption is completed, cool the solution. Polyethylene glycol 400 (1.0 wt% of the pretreated carbon black mass) was slowly added under stirring at 200 rpm. After the addition was completed, the mixture was stirred and adsorbed for 45 min at 30℃ and 200 rpm. Then, sodium carboxymethyl cellulose (15 wt% of the pretreated carbon black mass) was added, the pH of the system was adjusted to 7.5, the temperature was raised to 50℃, and the mixture was stirred and adsorbed for 80 min at 200 rpm for three times. After the treatment, the reaction solution was filtered, the precipitate was dried, and primary modified carbon black was obtained.

[0051] (3) Mix 1.5g of tannic acid and 80ml of 45v / v% ethanol solution, heat to 55℃, stir until the solid dissolves, adjust the pH of the system to 6.0, add 1g of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane under vigorous stirring, and stir at 55℃ for 3h after the addition is complete; cool to room temperature after the reaction is complete to obtain the modified solution; add primary modified carbon black (mass ratio of primary modified carbon black to tannic acid is 1:0.2-1.0) to the modified solution, ultrasonically disperse at 300W for 20min, adjust the pH of the system to 6.0, heat to 70℃, react for 6h, filter the reaction solution after the reaction is complete, wash the precipitate after filtration and dry to obtain secondary modified carbon black;

[0052] (4) Dissolve 2g of styrene-maleic anhydride copolymer in 500ml of DMF, add 1g of secondary modified carbon black, sonicate at 300W for 40min, then heat to 120℃, stir and react for 24h under an inert atmosphere. After the reaction is completed, cool to room temperature, filter the reaction system, wash the precipitate after filtration and dry it to obtain highly dispersible carbon black. Example 3

[0053] A method for preparing highly dispersible carbon black includes the following steps:

[0054] (1) Under an inert atmosphere, 4g of carbon black was mixed with 30ml of 65wt% nitric acid solution, heated to 100℃, and stirred at 800 rpm for 24h. After treatment, the mixture was cooled to room temperature, filtered, and the precipitate was washed with water until neutral. Then, it was dried under vacuum at 50℃ to obtain pretreated carbon black.

[0055] (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. Sonicate the dispersion at 100 W for 30 min, adjust the pH of the system to 7.0, and perform adsorption treatment by stirring once at 42℃ and 300 rpm for 1 h. After the adsorption is completed, cool the system. Polyethylene glycol 400 (1.5 wt% of the pretreated carbon black mass) was slowly added under stirring at 200 rpm. After the addition was completed, the mixture was stirred and adsorbed for 50 min at 32℃ and 200 rpm. Then, sodium carboxymethyl cellulose (18 wt% of the pretreated carbon black mass) was added, the pH of the system was adjusted to 7.5, the temperature was raised to 55℃, and the mixture was stirred and adsorbed for 90 min at 300 rpm for three times. After the treatment, the reaction solution was filtered, the precipitate was dried, and primary modified carbon black was obtained.

[0056] (3) Mix 2g of tannic acid and 80ml of 50v / v% ethanol solution, heat to 60℃, stir until the solid dissolves, adjust the pH of the system to 6.0, add 1g of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane under vigorous stirring, and stir at 60℃ for 4h after the addition is complete; after the reaction is complete, cool to room temperature to obtain modified solution; add primary modified carbon black (the mass ratio of primary modified carbon black to tannic acid is 1:1.0) to the modified solution, ultrasonically disperse at 500W for 30min, adjust the pH of the system to 6.0, heat to 80℃, react for 8h, after the reaction is complete, filter the reaction solution, wash the precipitate after filtration, and dry to obtain secondary modified carbon black;

[0057] (4) Dissolve 5g of styrene-maleic anhydride copolymer in 500ml of DMF, add 1g of secondary modified carbon black, sonicate at 300W for 60min, then heat to 130℃, stir and react for 48h under an inert atmosphere. After the reaction is completed, cool to room temperature, filter the reaction system, wash the precipitate after filtration and dry it to obtain highly dispersible carbon black.

[0058] To verify the dispersibility of the highly dispersible carbon black prepared in this invention in anhydrous ethanol, a detailed description is provided below with reference to several comparative examples.

[0059] Comparative Example 1

[0060] The difference between this comparative example and Example 3 is that step (2) does not include the step of adsorption treatment with octadecyl dimethyl benzyl ammonium chloride, while other operations are the same as in Example 3.

[0061] Comparative Example 2

[0062] The difference between this comparative example and Example 3 is that step (2) does not include the step of using polyethylene glycol 400 for adsorption treatment; the other operations are the same as in Example 3.

[0063] Comparative Example 3

[0064] The difference between this comparative example and Example 3 is that step (2) does not include the step of using sodium carboxymethyl cellulose for adsorption treatment, while other operations are the same as in Example 3.

[0065] Comparative Example 4

[0066] The difference between this comparative example and Example 3 is as follows: The specific process of step (3) is as follows: 2g of tannic acid and 80ml of 50v / v% ethanol solution are mixed, heated to 60℃, stirred until the solid dissolves, primary modified carbon black (the mass ratio of primary modified carbon black to tannic acid is 1:1.0) is added, ultrasonically dispersed at 500W for 30min, the pH of the system is adjusted to 6.0, the temperature is raised to 80℃, and the reaction is carried out for 8h. After the reaction is completed, the reaction solution is filtered, the precipitate is washed and dried to obtain secondary modified carbon black. Other steps are the same as in Example 3.

[0067] Comparative Example 5

[0068] The difference between this comparative example and Example 3 is as follows: The specific process of step (3) is as follows: 1g of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane and 80ml of 50v / v% ethanol solution are mixed, heated to 60℃, the pH of the system is adjusted to 6.0, and the mixture is stirred at 60℃ for 4h; after the reaction is completed, it is cooled to room temperature to obtain the modified solution; primary modified carbon black (the mass ratio of primary modified carbon black to tannic acid is 1:1.0) is added to the modified solution, ultrasonically dispersed at 500W for 30min, the pH of the system is adjusted to 6.0, the temperature is raised to 80℃, and the reaction is carried out for 8h. After the reaction is completed, the reaction solution is filtered, the precipitate is washed and dried to obtain secondary modified carbon black. Other steps are the same as in Example 3.

[0069] Comparative Example 6

[0070] The difference between this comparative example and Example 3 is that step (2) is not included, while the other operations are the same as in Example 3.

[0071] Comparative Example 7

[0072] The difference between this comparative example and Example 3 is that step (3) is not included, while the other operations are the same as in Example 3.

[0073] Comparative Example 8

[0074] The difference between this comparative example and Example 3 is that step (4) is not included; the other operations are the same as in Example 3.

[0075] 1g of the highly dispersible carbon black prepared in the above examples and comparative examples was mixed with 50ml of anhydrous ethanol and ultrasonically dispersed at 500W power for 30min to obtain different dispersions. The above dispersions were placed at room temperature for 120 days, and the state of the dispersions was observed every day during this period. The presence or absence of precipitation was observed by visual inspection. The test results are shown in Table 1.

[0076] Table 1

[0077]

[0078] As can be seen from the test results in Table 1, the carbon black pretreatment, primary modification, secondary modification, and polymer coating in Examples 1-3 respectively formed a multi-layer modified layer on the carbon black surface, resulting in highly dispersible carbon black that dispersed well in anhydrous ethanol and showed no precipitation after 120 days at room temperature. However, the comparative examples 1-8 lacked key modification steps, resulting in a decrease in the dispersibility of the highly dispersible carbon black.

[0079] Specifically, in the preparation of the first adsorption layer, octadecyl dimethyl benzyl ammonium chloride, as a cationic surfactant, initially reduces the surface energy of the pretreated carbon black through electrostatic adsorption; polyethylene glycol 400, as a nonionic surfactant, provides steric hindrance; and sodium carboxymethyl cellulose, as an anionic surfactant, enhances 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, the lack of adsorption treatment with octadecyl dimethyl benzyl ammonium chloride, polyethylene glycol 400, or sodium carboxymethyl cellulose resulted in a significant decrease in the dispersion effect of the highly dispersible carbon black in anhydrous ethanol.

[0080] In preparing the second adsorption layer, this invention uses a complex of tannic acid and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane as a modifier. The phenolic hydroxyl groups in 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 on 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 highly dispersible carbon black in anhydrous ethanol. The lack of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane in Comparative Example 4 and the lack of tannic acid in Comparative Example 5 resulted in a certain degree of decrease in the dispersibility of the highly dispersible carbon black prepared.

[0081] When treating carbon black, it is first modified with octadecyl dimethyl benzyl ammonium chloride, polyethylene glycol, and sodium carboxymethyl cellulose to achieve initial dispersion. Then, a second modification is performed using tannic acid and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane to enhance the interfacial bonding between the modified layer and the carbon black. Finally, polymer coating is used as a third modification to ensure the dispersion stability of the carbon black. These three modification methods work synergistically, allowing the highly dispersible carbon black to maintain its dispersion in anhydrous ethanol matrix for an extended period. In Comparative Examples 6-8, the absence of any one of the modification methods resulted in a certain degree of decrease in the dispersibility of the highly dispersible carbon black.

[0082] Application Example 1

[0083] A method for preparing a tire tread compound composition containing highly dispersible carbon black includes the following steps:

[0084] S1. Preheat the internal mixer to 50°C, add 55 parts of natural rubber, 23 parts of solution-polymerized styrene-butadiene rubber, and 12 parts of cis-butadiene rubber, and mix at 50 rpm for 60 seconds until the raw rubber is uniformly wrapped around the rollers. Add 8 parts of the highly dispersible carbon black prepared in Example 1, 3 parts of zinc oxide, 2 parts of stearic acid, 2.0 parts of antioxidant 4020, 1.0 part of antioxidant RD, and 1.2 parts of microcrystalline wax to the internal mixer in sequence. Raise the temperature to 145°C at 80 rpm, add the remaining 8 parts of the highly dispersible carbon black prepared in Example 1 and 13 parts of environmentally friendly aromatic oil TDAE, and continue mixing until the temperature reaches 145°C again. Discharge the rubber to the open mill, pass it through the mill 4 times at 60°C, form a triangular bundle, and sheet it to obtain the masterbatch.

[0085] S2. After the masterbatch has been left to stand for 24 hours, it is put into a mixer preheated to 50°C and mixed at 40 rpm for 1 minute to soften the masterbatch evenly. 1.5 parts sulfur, 0.4 parts accelerator D, and 1.3 parts accelerator CZ are added and mixed at 50 rpm for 2 minutes. The mixture is then discharged into a two-roll mill with a roller temperature of 50°C, passed through a thin mill 5 times, formed into triangular bundles, and sheeted. During the discharge process, the discharge temperature must be strictly controlled below 108°C to obtain the tire tread rubber composition.

[0086] Application Example 2

[0087] The difference from Application Example 1 is that an equal amount of highly dispersed carbon black from Example 2 is used instead of the highly dispersed carbon black from Example 1, while the other operations are the same as in Application Example 1.

[0088] Application Example 3

[0089] The difference from Application Example 1 is that an equal amount of highly dispersed carbon black from Example 3 is used instead of the highly dispersed carbon black from Example 1, while the other operations are the same as in Application Example 1.

[0090] Application Comparative Example 1

[0091] The difference from Application Example 1 is that an equal amount of highly dispersed carbon black from Comparative Example 1 is used instead of the highly dispersed carbon black from Example 1, while other operations are the same as in Application Example 1.

[0092] Application Comparative Example 2

[0093] The difference from Application Example 1 is that an equal amount of highly dispersed carbon black from Comparative Example 2 is used instead of the highly dispersed carbon black from Example 1, while other operations are the same as in Application Example 1.

[0094] Application Comparative Example 3

[0095] The difference from Application Example 1 is that an equal amount of highly dispersed carbon black from Comparative Example 3 is used to replace the highly dispersed carbon black from Example 1, while other operations are the same as in Application Example 1.

[0096] Application Comparative Example 4

[0097] The difference from Application Example 1 is that an equal amount of highly dispersed carbon black from Comparative Example 4 is used instead of the highly dispersed carbon black from Example 1, while other operations are the same as in Application Example 1.

[0098] Application Comparative Example 5

[0099] The difference from Application Example 1 is that an equal amount of highly dispersed carbon black from Comparative Example 5 is used instead of the highly dispersed carbon black from Example 1, while other operations are the same as in Application Example 1.

[0100] Application Comparative Example 6

[0101] The difference from Application Example 1 is that an equal amount of highly dispersed carbon black from Comparative Example 6 is used instead of the highly dispersed carbon black from Example 1, while other operations are the same as in Application Example 1.

[0102] Application Comparative Example 7

[0103] The difference from Application Example 1 is that an equal amount of highly dispersed carbon black from Comparative Example 7 is used instead of the highly dispersed carbon black from Example 1, while other operations are the same as in Application Example 1.

[0104] Application Comparative Example 8

[0105] The difference from Application Example 1 is that an equal amount of highly dispersed carbon black from Comparative Example 8 is used instead of the highly dispersed carbon black from Example 1, while the other operations are the same as in Application Example 1.

[0106] The tire tread compound compositions prepared in Application Examples 1-3 and Comparative Examples 1-8 were subjected to performance tests. The test methods and results are as follows:

[0107] 1. Mechanical property testing:

[0108] Tensile strength and elongation at break were tested in accordance with GB / T528-2009.

[0109] 2. Abrasion resistance test:

[0110] Abrasion resistance tests were conducted according to GB / T1689-1998, "Determination of Abrasion Resistance of Vulcanized Rubber".

[0111] The test results are shown in Table 2.

[0112] 3. Hot air aging performance test:

[0113] The test samples were placed in a 401A aging chamber and aged at 100℃ 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.

[0114] 4. Low-temperature performance test:

[0115] The test samples were placed at -80℃ 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.

[0116] Table 2 (Unprocessed)

[0117]

[0118] Table 3 (100℃×48h)

[0119]

[0120] Table 4 (-80℃ × 7 days)

[0121]

[0122] As can be seen from Tables 2, 3 and 4, the highly dispersible carbon black prepared by this invention, when applied to tire tread compound, produces a composition with not only good tensile properties, but also excellent wear resistance, heat aging resistance, and low-temperature resistance.

[0123] Compared to Examples 1-3, the high-dispersibility carbon black prepared in Comparative Examples 1-8 lacked a certain modification step, resulting in a decrease in the overall performance of the composition when added to the tire tread compound.

[0124] Specifically, in Comparative Example 1, the lack of adsorption treatment of octadecyl dimethyl benzyl ammonium chloride in the preparation of the highly dispersed carbon black resulted in poor dispersion of the carbon black in the tire tread compound, significantly reducing the wear resistance of the composition. In Comparative Example 2, the lack of adsorption treatment of polyethylene glycol 400 in the highly dispersed carbon black led to uneven mixing during the preparation of the tire tread compound composition, resulting in a certain degree of decrease in the elongation at break of the composition after low-temperature treatment. In Comparative Example 3, the lack of adsorption treatment of sodium carboxymethyl cellulose weakened the steric hindrance effect, making it difficult for the highly dispersed carbon black to remain stable in the tire tread compound for a long period, significantly deteriorating the composition's resistance to hot air aging and low-temperature performance.

[0125] In Comparative Examples 4 and 5, the lack of modification with tannic acid or N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane weakened the interfacial bonding between carbon black and the modified layer, resulting in a significant decrease in the tensile properties of the tire tread compound composition after aging. In Comparative Example 6, the highly dispersed carbon black lacked a first adsorption layer, leading to poor initial dispersion and affecting subsequent modification; the resulting tire tread compound composition showed the most significant decrease in overall performance. In Comparative Example 7, the highly dispersed carbon black lacked modification with tannic acid / N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, resulting in poor dispersion and numerous agglomerates in the tire tread compound matrix, leading to increased local frictional heat and decreased wear resistance. In Comparative Example 8, the highly dispersed carbon black lacked a polymer coating step, resulting in poor bonding between the highly dispersed carbon black and the tire tread compound matrix, significantly reducing the material's wear resistance.

[0126] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of these embodiments are merely to aid in understanding the method and core ideas of the present invention, including the best mode, and to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims. The scope of protection of this patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements similar to those expressed in the claims, or if they include equivalent structural elements that are not substantially different from those expressed in the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. A highly dispersible carbon black, characterized in that, The method for preparing the highly dispersible carbon black includes the following steps: (1) Activate carbon black to obtain pretreated carbon black; the activation process is as follows: under an inert atmosphere, mix carbon black with a nitric acid solution with a concentration of 50-65wt%, control the ratio of carbon black to nitric acid solution to 2g: (8-15)ml, heat to 90-100℃, stir for 24-36h at 500-800 rpm, cool to room temperature after treatment, filter, wash the precipitate with water until neutral, and then dry. (2) Disperse the pretreated carbon black in deionized water to obtain a pretreated carbon black aqueous dispersion. Add octadecyl dimethyl benzyl ammonium chloride to the pretreated carbon black aqueous dispersion, and adjust the pH of the system after ultrasonic dispersion. Perform a first stirring adsorption treatment. After the adsorption is completed, cool the system and add polyethylene glycol under stirring. After the addition is completed, perform a second stirring adsorption treatment. Then add sodium carboxymethyl cellulose, adjust the pH of the system, and heat the system for a third stirring adsorption treatment. After the treatment is completed, filter the reaction solution, and dry the precipitate after filtration to obtain 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 the reaction after the addition is complete; cool to room temperature after the reaction is complete to obtain modified solution; add primary modified carbon black to the modified solution, disperse by ultrasonication, adjust the pH of the system, heat the reaction, filter the reaction solution after the reaction is complete, wash the precipitate after filtration and dry it to obtain secondary modified carbon black; (4) The styrene-maleic anhydride copolymer was dissolved in DMF, and secondary modified carbon black was added. The mixture was ultrasonically treated, then heated and stirred under an inert atmosphere. After the reaction was completed, the mixture was cooled to room temperature, the reaction system was filtered, and the precipitate was washed and dried to obtain highly dispersed carbon black.

2. The highly dispersible carbon black according to claim 1, characterized in that: In step (2), the pH of the system is adjusted to 6.0-7.0 after adding octadecyl dimethyl benzyl ammonium chloride; the pH of the system is adjusted to 7.5 after adding sodium carboxymethyl cellulose; 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 ultrasonic dispersion power is 100W, and the time is 20-30 min; the temperature of the first stirring adsorption treatment is 38-42℃, the time is 1 h, and the stirring speed is 300 rpm.

3. The highly dispersible carbon black according to claim 1, characterized in that: In step (2), the polyethylene glycol is polyethylene glycol 400, the amount of polyethylene glycol added is 0.5-1.5 wt% of the pretreated carbon black, the temperature of the secondary stirring adsorption treatment is 28-32℃, the time is 40-50 min, and the stirring speed is 200 rpm.

4. The highly dispersible carbon black according to claim 1, characterized in that: In step (2), the amount of sodium carboxymethyl cellulose added is 13-18 wt% of the pretreated carbon black; the temperature of the three-stage stirring adsorption treatment is 45-55℃, the time is 60-90 min, and the stirring speed is 200-300 rpm.

5. The highly dispersible carbon black according to claim 1, characterized in that: In step (3), the concentration of the ethanol solution is 45-50 v / v%, and the mass ratio of the tannic acid to N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane is (1-2):1; the stirring reaction temperature is 50-60℃ and the time is 2-4h.

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

7. The highly dispersible carbon black according to claim 1, characterized in that: 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 200-300W, the time is 30-60min, the reaction temperature is 110-130℃, and the reaction time is 12-48h.

8. The use of a highly dispersible carbon black according to any one of claims 1-7 in a tire tread compound composition.

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