Preparation method of lignin / white carbon black two-phase filler and reinforcing / anti-aging dual-function application of lignin / white carbon black two-phase filler

Abstract

The invention discloses a preparation method of lignin / white carbon black two-phase filler and reinforcing / anti-aging dual-function application, and belongs to the field of reinforcing filler. According to the invention, dibutyltin dilaurate is adopted as a catalyst, lignin polyphenol in lignin is promoted to react with alcoholic hydroxyl groups on the surface of white carbon black, and a core-shell double-phase structure with white carbon black as a core and lignin as a shell is constructed. In the two-phase filler, rich phenolic hydroxyl groups on the surface of a lignin shell layer can efficiently capture free radicals to realize aging resistance, and can also be fixed on the surface of white carbon black through chemical bond bridging to inhibit migration; in addition, the lignin shell layer also effectively isolates white carbon black particles and improves the dispersibility of the white carbon black particles, and in combination with the reinforcing effect of the white carbon black core, the synergistic improvement of reinforcing and anti-aging functions is finally realized.

Description

Technical Field

[0001] This invention relates to a method for preparing a lignin / fumed silica dual-phase filler and its dual-function application of reinforcement and anti-aging, belonging to the field of reinforcement fillers. Background Technology

[0002] Rubber, as a high-volume and widely used polymer material, is commonly used in many important industrial and consumer sectors, including tire manufacturing, automotive seals, industrial hoses, and various daily-use rubber products. General-purpose olefin rubbers, represented by natural rubber, are chemically reactive due to the presence of numerous unsaturated double bonds and highly reactive allyl hydrogens in their molecular chains. During long-term use, they are easily affected by various environmental factors such as heat, oxygen, ozone, and light, resulting in the generation of harmful free radicals. These free radicals can further induce the breakage or excessive cross-linking of rubber molecular chains, ultimately leading to the degradation of material properties, such as hardening, embrittlement, or softening. On the other hand, unreinforced pure rubber has poor mechanical properties; its tensile strength, modulus, and abrasion resistance cannot meet the basic requirements of practical applications. Therefore, in the actual production of rubber products, reinforcing fillers and antioxidants are usually added to synergistically improve their overall performance.

[0003] Silica, as an important reinforcing filler, is widely regarded as a milestone material in the development of the rubber industry. Tires made using silica as a reinforcing filler can significantly reduce rolling resistance by about 20%, equivalent to fuel savings of 3%-5%, while also improving wet skid resistance and greatly enhancing driving safety. However, due to its extremely small particle size, large specific surface area, high surface energy, and rich hydrophilic silanol content, silica has poor compatibility with non-polar olefin rubbers and is prone to agglomeration, thus affecting its dispersion in the rubber matrix and the performance of the final composite material.

[0004] Currently, the antioxidants widely used in industry mainly include amine antioxidants (such as antioxidants 4010NA and 6PPD) and phenolic antioxidants (such as antioxidants BHT, SP, and BHA). Although these traditional antioxidants show good protective effects in delaying rubber aging, their synthesis processes are usually complex, some products have certain biotoxicity, and they are difficult to degrade in the natural environment, posing potential risks to the environment and human health. In addition, most of these antioxidants are small molecule compounds, which are prone to migration due to poor compatibility after blending with rubber, resulting in surface blooming, which not only affects the appearance of the product but also causes its protective performance to gradually decline over time. Patent CN117887099A proposes to improve the anti-aging performance of rubber materials by amination modification of lignin and blending it with rubber; however, this method only achieves a simple physical mixing and fails to achieve a synergistic enhancement of reinforcement and anti-aging functions in essence. Another patent, CN103387677A, uses alkali-treated lignin and carbon black together in rubber preparation. Although it partially utilizes natural raw materials, it still relies on the assistance of traditional antioxidants and fails to completely solve the problems of migration and environmental pollution caused by small molecule antioxidants. Summary of the Invention

[0005] [Technical Issues] Existing technologies require the use of antioxidants to achieve anti-aging effects on rubber.

[0006] [Technical Solution] Based on this, the present invention proposes to use dibutyltin dilaurate as a catalyst to promote the reaction between lignin in lignin and the hydroxyl groups on the surface of silica, constructing a core-shell biphase structure with silica as the core and lignin as the shell. In this biphase filler, the abundant phenolic hydroxyl groups on the surface of the lignin shell can efficiently capture free radicals to achieve anti-aging, and can also be fixed to the silica surface through chemical bonds to inhibit migration; in addition, the lignin shell effectively isolates silica particles to improve their dispersibility. Combined with the reinforcing effect of the silica core, the synergistic improvement of reinforcement and anti-aging functions is ultimately achieved.

[0007] The first objective of this invention is to provide a method for preparing lignin / fumed silica dual-phase filler, the method being as follows: (1) The lignin and silica are uniformly dispersed in an organic solvent to prepare a mixed suspension; (2) Add dibutyltin dilaurate to the mixed suspension in step (1), and carry out catalytic reaction, cooling, filtration, washing and drying under an inert atmosphere to obtain a biphase packing.

[0008] In one embodiment of the present invention, in step (1), lignin and silica are mixed in a mass ratio of (1:2) to (2:1).

[0009] In one embodiment of the present invention, in step (1), the total mass concentration of lignin and silica is 10% to 20%.

[0010] In one embodiment of the present invention, in step (1), the phenolic hydroxyl content of the lignin is 6~10 mmol / g.

[0011] In one embodiment of the present invention, in step (1), the lignin is a powder obtained by crushing, sieving and drying.

[0012] Preferably, the lignin is pulverized, passed through an 80-200 mesh sieve, and dried at 60-80°C for 2-4 hours.

[0013] More preferably, the lignin is pulverized, passed through a 100-200 mesh sieve, and dried at 70-90°C for 2-4 hours.

[0014] In one embodiment of the present invention, in step (1), the specific surface area of ​​the silica is 100~300 m². 2 / g.

[0015] Preferably, the specific surface area of ​​the silica is 200 m². 2 / g.

[0016] In one embodiment of the present invention, in step (1), the silica is activated at 100~120°C for 1~2 h.

[0017] In one embodiment of the present invention, the organic solvent is one or more of ethanol, acetone, tetrahydrofuran, and toluene.

[0018] In one embodiment of the present invention, in step (2), the amount of dibutyltin dilaurate added is 0.5% to 3% of the total mass of lignin and silica.

[0019] In one embodiment of the present invention, in step (2), the inert atmosphere is one or more of nitrogen, argon, and helium.

[0020] In one embodiment of the present invention, in step (2), the catalytic reaction is carried out at 80~110°C for 4~12 hours.

[0021] Preferably, the catalytic reaction is carried out at 80-100°C for 8-12 h.

[0022] In one embodiment of the present invention, in step (2), the product is washed with ethanol 4 to 5 times, and then washed with water 3 to 4 times.

[0023] In one embodiment of the present invention, in step (2), the product is dried at 60-80 °C for 6-12 h.

[0024] Preferably, the product is dried at 70-80℃ for 10-12 hours.

[0025] A second object of the present invention is to provide a biphase packing material prepared according to the above method.

[0026] A third objective of this invention is to provide the application of the biphase filler in the preparation of rubber materials, wherein the application is to add the biphase filler during the preparation of rubber materials.

[0027] The fourth object of the present invention is to provide a rubber composite material made from the following raw materials in parts by weight: olefin rubber: 100 parts; stearic acid: 1-5 parts; accelerator: 1-5 parts; duplex filler: 20-40 parts; reinforcing filler: 5-10 parts; vulcanizing agent: 1-3 parts.

[0028] In one embodiment of the present invention, the olefin rubber includes one or more of styrene-butadiene rubber, cis-butadiene rubber, isoprene rubber, ethylene propylene rubber, butyl rubber, nitrile rubber, and chloroprene rubber.

[0029] In one embodiment of the present invention, the accelerator is one or a mixture of two of accelerators CZ and D.

[0030] In one embodiment of the present invention, the accelerator is 1 to 5 parts of accelerator CZ and 0.1 to 1 part of accelerator D.

[0031] In one embodiment of the invention, the vulcanizing agent comprises sulfur.

[0032] In one embodiment of the present invention, the reinforcing filler is one or a mixture of carbon black and silica.

[0033] The fifth objective of this invention is to provide a method for preparing the above-mentioned rubber composite material, the method being as follows: olefin rubber is plasticized at room temperature for 4-8 min; then, duplex filler and reinforcing filler are added, and the mixture is kneaded for 4-8 min, with repeated kneading during this period; stearic acid and an accelerator are then added, and the mixture is further kneaded for 4-8 min, with 3-5 triangular wrappings during this period; a vulcanizing agent is added, and the mixture is kneaded for 2-5 min, with 3-5 triangular wrappings and 3-5 rollings to obtain a compound; the compound is then molded and vulcanized at 160-170 °C and 12-15 MPa to obtain the rubber composite material.

[0034] In one embodiment of the present invention, the olefin rubber includes one or more of styrene-butadiene rubber, cis-butadiene rubber, isoprene rubber, ethylene propylene rubber, butyl rubber, nitrile rubber, and chloroprene rubber.

[0035] In one embodiment of the present invention, the accelerator is one or a mixture of two of accelerators CZ and D.

[0036] In one embodiment of the present invention, the accelerator is 1 to 5 parts of accelerator CZ and 0.1 to 1 part of accelerator D.

[0037] In one embodiment of the invention, the vulcanizing agent comprises sulfur.

[0038] In one embodiment of the present invention, the reinforcing filler is one or a mixture of carbon black and silica.

[0039] A sixth object of the present invention is to provide the application of the method for preparing the biphase filler, or the biphase filler, the rubber composite material, or the method for preparing the rubber composite material in the fields of automobile manufacturing, sporting goods, building materials, aerospace, and medical devices.

[0040] Optionally, the automotive manufacturing field includes the production of key rubber products such as tires, automotive seals, and automotive shock absorber components.

[0041] Optionally, the sporting goods field includes the manufacture of sports shoe soles and sports equipment handles.

[0042] Optionally, the field of building materials includes the preparation of waterproof membranes and sealing strips.

[0043] Optionally, the aerospace field includes the manufacture of aircraft tires and seals.

[0044] [Beneficial Effects] 1. Constructing a stable biphase structure: This invention utilizes dibutyltin dilaurate to catalyze an indirect reaction between lignin polyphenols in lignin and alcohol hydroxyl groups on the surface of silica, thereby firmly encapsulating lignin on the surface of silica and forming a core-shell biphase structure. This effectively avoids the lignin migration problem caused by the separation of the two phases due to physical mixing, and significantly improves structural stability.

[0045] 2. Balancing reinforcement and anti-aging: The silica core can significantly improve the mechanical properties of styrene-butadiene rubber, achieving efficient reinforcement; the lignin shell is rich in phenolic hydroxyl groups, which can capture free radicals generated during rubber aging, inhibit rubber degradation, and achieve anti-aging function. Its anti-aging effect is similar to that of traditional amine and phenolic antioxidants.

[0046] 3. Improved compatibility: By adding silane coupling agents, the surface polarity of the duplex filler can be effectively reduced, improving its compatibility and dispersibility with non-polar styrene-butadiene rubber, reducing filler agglomeration, and further enhancing the overall performance of the modified rubber.

[0047] 4. Green, environmentally friendly and low-cost: Lignin is a natural and renewable resource with wide availability and low price. It can replace some traditional chemical antioxidants and reinforcing fillers, which not only reduces production costs but also reduces the environmental harm caused by chemical reagents, which is in line with the trend of green chemical development. Attached Figure Description

[0048] Figure 1 This is the Fourier transform infrared (FTIR) spectrum of the present invention. Detailed Implementation

[0049] The preferred embodiments of the present invention are described below. It should be understood that the embodiments are for better explanation of the present invention and are not intended to limit the present invention.

[0050] The raw materials involved in the following embodiments: Lignin: purchased from Jiangsu Tianshun Biotechnology Co., Ltd.; precipitated silica, acetone, ethanol, tetrahydrofuran, toluene, stearic acid, accelerator CZ, and accelerator D were all purchased from Maclean Company; dibutyltin dilaurate: purchased from Aladdin Company; styrene-butadiene rubber: purchased from Guangzhou Rubber Research Institute; sulfur: purchased from Guangzhou Chemical Reagent Factory.

[0051] The detection methods involved in the following embodiments: Fourier transform infrared spectroscopy (FTIR) Example 1: Preparation and application of lignin / fumed silica duplex filler 1. Preparation of lignin / fumed silica duplex filler In this embodiment, lignin (phenolic hydroxyl content of 6 mmol / g) and silica (specific surface area of ​​200 m²) are mixed. 2 The biphase packing material was prepared by dissolving (g) in an organic solvent (acetone) and reacting it with a catalyst (dibutyltin dilaurate). The steps are as follows: (1) The lignin (phenolic hydroxyl content of 6 mmol / g) was pulverized and passed through a 100-mesh sieve, placed in a vacuum drying oven, and dried at 70 °C for 3 h to obtain lignin powder; (2) Add silica (specific surface area of ​​200 m²) 2 / g) was placed in a muffle furnace and activated at 110 °C for 1.5 h to obtain pretreated silica; (3) Weigh lignin powder and silica at a mass ratio of 1:2, then add the mixed powder to acetone solution and stir thoroughly to obtain a uniformly dispersed mixed suspension; the total mass concentration of lignin and silica in the suspension (i.e., the percentage of total solid mass to total suspension mass) is 15%; (4) Add the catalyst dibutyltin dilaurate (1% of the total mass of lignin powder and silica) to the mixed suspension in step (3), and react at 95 °C for 8 h under nitrogen protection, with continuous stirring (500 rpm). (5) After the reaction is completed, cool to room temperature, filter and collect solid product; wash solid product with ethanol 4 times; wash solid product with water 3 times, place the washed solid in a vacuum drying oven and dry at 70 °C for 12 h to obtain No. 1 composite filler.

[0052] The No. 1 composite filler was characterized by FTIR. After the lignin reacted with silica, the chromatogram showed a high chromatogram at 3500 cm⁻¹. -1 -3200cm -1 The characteristic peak of the phenolic hydroxyl group appears nearby, at 1450 cm⁻¹. -1 -1600cm -1 The presence of characteristic peaks of the benzene ring indicates that the reaction between lignin and silica was successful. Figure 1 ).

[0053] 2. Application of lignin / fumed silica dual-phase filler in the preparation of rubber composite materials The styrene-butadiene rubber was plasticized on a two-roll mill for 4 min; stearic acid, accelerator CZ, and accelerator D were added, and the mixture was continued for 4 min; the duplex filler and silica prepared in step 1 were added, and the mixture was mixed for 4 min, followed by 5 triangular wraps; sulfur was added, and the mixture was mixed for 3 min, followed by 5 triangular wraps, and rolled 3 times to obtain the compound; the compound was then molded and vulcanized at 170℃ and 12 MPa for 20 min to obtain the rubber composite material.

[0054] Table 1 Preparation of rubber composite materials

[0055] Example 2: Preparation and application of lignin / fumed silica duplex filler The synthesis process in this embodiment is similar to that in Example 1, except that the organic solvent for dispersing lignin and silica is tetrahydrofuran. 1. Preparation of lignin / fumed silica duplex filler (1) The lignin (phenolic hydroxyl content of 6 mmol / g) was pulverized and passed through a 100-mesh sieve, placed in a vacuum drying oven, and dried at 70 °C for 3 h to obtain lignin powder; (2) Add silica (specific surface area of ​​200 m²) 2 / g) was placed in a muffle furnace and activated at 110 °C for 1.5 h to obtain pretreated silica; (3) Weigh lignin powder and silica at a mass ratio of 1:2, then add the mixed powder to a tetrahydrofuran solution and stir thoroughly to obtain a uniformly dispersed mixed suspension; the total mass concentration of lignin and silica in the suspension (i.e., the percentage of the total mass of solids to the total mass of the suspension) is 15%; (4) Add the catalyst dibutyltin dilaurate (1% of the total mass of lignin powder and fumed silica) to the mixed suspension in step (3), and react at 95 °C for 8 h under nitrogen protection, with continuous stirring (500 rpm). (5) After the reaction is completed, cool to room temperature, filter and collect solid product; wash solid product with ethanol 4 times; wash solid product with water 3 times, place the washed solid in a vacuum drying oven and dry at 70 °C for 12 h to obtain No. 2 composite filler.

[0056] 2. Application of lignin / fumed silica dual-phase filler in the preparation of rubber composite materials Same as Example 1.

[0057] Example 3: Preparation and application of lignin / fumed silica duplex filler The synthesis process in this embodiment is similar to that in Example 1, except that the organic solvent for dispersing lignin and silica is toluene. 1. Preparation of lignin / fumed silica duplex filler (1) The lignin (phenolic hydroxyl content of 10 mmol / g) was pulverized and passed through a 150-mesh sieve, placed in a vacuum drying oven, and dried at 70 °C for 3 h to obtain lignin powder; (2) Add silica (specific surface area of ​​150 m²) 2 / g) was placed in a muffle furnace and activated at 110 °C for 1.5 h to obtain pretreated silica; (3) Weigh lignin powder and silica at a mass ratio of 1:2, then add the mixed powder to toluene solution and stir thoroughly to obtain a uniformly dispersed mixed suspension; the total mass concentration of lignin and silica in the suspension (i.e., the percentage of total solid mass to total suspension mass) is 15%; (4) Add the catalyst dibutyltin dilaurate (1% of the total mass of lignin powder and silica) to the mixed suspension in step (3), and react at 95 °C for 10 h under nitrogen protection, with continuous stirring (500 rpm). (5) After the reaction is completed, cool to room temperature, filter and collect solid product; wash solid product with ethanol 4 times; wash solid product with water 3 times, place the washed solid in a vacuum drying oven and dry at 70 °C for 12 h to obtain No. 3 composite filler.

[0058] 2. Application of lignin / fumed silica dual-phase filler in the preparation of rubber composite materials Same as Example 1.

[0059] Example 4: Preparation and application of lignin / fumed silica dual-phase filler The synthesis process in this embodiment is similar to that in Example 1, except that the organic solvent for dispersing lignin and silica is anhydrous ethanol. 1. Preparation of lignin / fumed silica duplex filler (1) The lignin (phenolic hydroxyl content of 10 mmol / g) was pulverized and passed through a 200-mesh sieve, placed in a vacuum drying oven, and dried at 70 °C for 3 h to obtain lignin powder; (2) Add silica (specific surface area of ​​300 m²) 2 / g) was placed in a muffle furnace and activated at 120 °C for 2 h to obtain pretreated silica; (3) Weigh lignin powder and silica at a mass ratio of 1:2, then add the mixed powder to anhydrous ethanol solution and stir thoroughly to obtain a uniformly dispersed mixed suspension; the total mass concentration of lignin and silica in the suspension (i.e., the percentage of total solid mass to total suspension mass) is 15%; (4) Add the catalyst dibutyltin dilaurate (1% of the total mass of lignin powder and fumed silica) to the mixed suspension in step (3), and react at 95 °C for 8 h under nitrogen protection, with continuous stirring (500 rpm). (5) After the reaction is completed, cool to room temperature, filter and collect solid product; wash solid product with ethanol 4 times; wash solid product with water 3 times, place the washed solid in a vacuum drying oven and dry at 80 °C for 12 h to obtain No. 4 composite filler.

[0060] 2. Application of lignin / fumed silica dual-phase filler in the preparation of rubber composite materials Same as Example 1.

[0061] Example 5: Preparation and application of lignin / fumed silica duplex filler The synthesis process in this embodiment is similar to that in Example 1, except that the mass ratio of lignin to silica is 1:1; and the amount of duplex filler (33 phr) and silica (9 phr) added is adjusted when preparing the rubber composite material. 1. Preparation of lignin / fumed silica duplex filler (1) The lignin (phenolic hydroxyl content of 6 mmol / g) was pulverized and passed through a 100-mesh sieve, placed in a vacuum drying oven, and dried at 70 °C for 3 h to obtain lignin powder; (2) Add silica (specific surface area of ​​200 m²) 2 / g) was placed in a muffle furnace and activated at 110 °C for 1.5 h to obtain pretreated silica; (3) Weigh lignin powder and silica at a mass ratio of 1:1, then add the mixed powder to acetone solution and stir thoroughly to obtain a uniformly dispersed mixed suspension; the total mass concentration of lignin and silica in the suspension (i.e., the percentage of total solid mass to total suspension mass) is 15%; (4) Add the catalyst dibutyltin dilaurate (1% of the total mass of lignin powder and fumed silica) to the mixed suspension in step (3), and react at 95 °C for 8 h under nitrogen protection, with continuous stirring (500 rpm). (5) After the reaction is completed, cool to room temperature, filter and collect solid product; wash solid product with ethanol 4 times; wash solid product with water 3 times, place the washed solid in a vacuum drying oven and dry at 70 °C for 12 h to obtain No. 5 composite filler.

[0062] 2. Application of lignin / fumed silica dual-phase filler in the preparation of rubber composite materials The synthesis process in this embodiment is similar to that in Example 1, except that the amount of duplex filler added is adjusted to 33 phr and the amount of silica added is adjusted to 9 phr. Table 2 Preparation of rubber composite materials

[0063] Example 6: Preparation and application of lignin / fumed silica duplex filler The synthesis process in this embodiment is similar to that in Example 1, except that the mass ratio of lignin to silica is 2:1; and the amount of duplex filler (23 phr) and silica (19 phr) added is adjusted when preparing the rubber composite material. 1. Preparation of lignin / fumed silica duplex filler (1) The lignin (phenolic hydroxyl content of 6 mmol / g) was pulverized and passed through a 100-mesh sieve, placed in a vacuum drying oven, and dried at 70 °C for 3 h to obtain lignin powder; (2) Add silica (specific surface area of ​​200 m²) 2 / g) was placed in a muffle furnace and activated at 110 °C for 1.5 h to obtain pretreated silica; (3) Weigh lignin powder and silica at a mass ratio of 2:1, then add the mixed powder to acetone solution and stir thoroughly to obtain a uniformly dispersed mixed suspension; the total mass concentration of lignin and silica in the suspension (i.e., the percentage of total solid mass to total suspension mass) is 15%; (4) Add the catalyst dibutyltin dilaurate (1% of the total mass of lignin powder and fumed silica) to the mixed suspension in step (3), and react at 95 °C for 8 h under nitrogen protection, with continuous stirring (500 rpm). (5) After the reaction is completed, cool to room temperature, filter and collect solid product; wash solid product with ethanol 4 times; wash solid product with water 3 times, place the washed solid in a vacuum drying oven and dry at 70 °C for 12 h to obtain 6# composite filler.

[0064] 2. Application of lignin / fumed silica dual-phase filler in the preparation of rubber composite materials The synthesis process in this embodiment is similar to that in Example 1, except that the amount of duplex filler added is adjusted to 23 phr and the amount of silica added is adjusted to 19 phr. Table 3 Preparation of rubber composite materials

[0065] Example 7: Preparation and application of lignin / fumed silica duplex filler The synthesis process in this embodiment is similar to that in Example 1, except that the reaction temperature is 80 °C. 1. Preparation of lignin / fumed silica duplex filler (1) The lignin (phenolic hydroxyl content of 6 mmol / g) was pulverized and passed through a 100-mesh sieve, placed in a vacuum drying oven, and dried at 70 °C for 3 h to obtain lignin powder; (2) Add silica (specific surface area of ​​200 m²) 2 / g) was placed in a muffle furnace and activated at 110 °C for 1.5 h to obtain pretreated silica; (3) Weigh lignin powder and silica at a mass ratio of 1:2, then add the mixed powder to acetone solution and stir thoroughly to obtain a uniformly dispersed mixed suspension; the total mass concentration of lignin and silica in the suspension (i.e., the percentage of total solid mass to total suspension mass) is 15%; (4) Add the catalyst dibutyltin dilaurate (1% of the total mass of lignin powder and silica) to the mixed suspension in step (3), and react at 80 °C for 8 h under nitrogen protection, with continuous stirring (500 rpm). (5) After the reaction is completed, cool to room temperature, filter and collect solid product; wash solid product with ethanol 4 times; wash solid product with water 3 times, place the washed solid in a vacuum drying oven and dry at 70 °C for 12 h to obtain 7# composite filler.

[0066] 2. Application of lignin / fumed silica dual-phase filler in the preparation of rubber composite materials Same as Example 1.

[0067] Example 8: Preparation and application of lignin / fumed silica duplex filler The synthesis process in this embodiment is similar to that in Example 1, except that the reaction temperature is 90 °C. 1. Preparation of lignin / fumed silica duplex filler (1) The lignin (phenolic hydroxyl content of 6 mmol / g) was pulverized and passed through a 100-mesh sieve, placed in a vacuum drying oven, and dried at 70 °C for 3 h to obtain lignin powder; (2) Add silica (specific surface area of ​​200 m²) 2 / g) was placed in a muffle furnace and activated at 110 °C for 1.5 h to obtain pretreated silica; (3) Weigh lignin powder and silica at a mass ratio of 1:2, then add the mixed powder to acetone solution and stir thoroughly to obtain a uniformly dispersed mixed suspension; the total mass concentration of lignin and silica in the suspension (i.e., the percentage of total solid mass to total suspension mass) is 15%; (4) Add the catalyst dibutyltin dilaurate (1% of the total mass of lignin powder and fumed silica) to the mixed suspension in step (3), and react at 90 °C for 8 h under nitrogen protection, with continuous stirring (500 rpm). (5) After the reaction is completed, cool to room temperature, filter and collect solid product; wash solid product with ethanol 4 times; wash solid product with water 3 times, place the washed solid in a vacuum drying oven and dry at 70 °C for 12 h to obtain No. 8 composite filler.

[0068] 2. Application of lignin / fumed silica dual-phase filler in the preparation of rubber composite materials Same as Example 1.

[0069] Example 9: Preparation and application of lignin / fumed silica duplex filler The synthesis process in this embodiment is similar to that in Example 1, except that the catalyst is 1.5% dibutyltin dilaurate by mass. 1. Preparation of lignin / fumed silica duplex filler (1) The lignin (phenolic hydroxyl content of 6 mmol / g) was pulverized and passed through a 100-mesh sieve, placed in a vacuum drying oven, and dried at 70 °C for 3 h to obtain lignin powder; (2) Add silica (specific surface area of ​​200 m²) 2 / g) was placed in a muffle furnace and activated at 110 °C for 1.5 h to obtain pretreated silica; (3) Weigh lignin powder and silica at a mass ratio of 1:2, then add the mixed powder to acetone solution and stir thoroughly to obtain a uniformly dispersed mixed suspension; the total mass concentration of lignin and silica in the suspension (i.e., the percentage of total solid mass to total suspension mass) is 15%; (4) Add the catalyst dibutyltin dilaurate (1.5% of the total mass of lignin powder and fumed silica) to the mixed suspension in step (3), and react at 95 °C for 8 h under nitrogen protection, with continuous stirring (500 rpm). (5) After the reaction is completed, cool to room temperature, filter and collect solid product; wash solid product with ethanol 4 times; wash solid product with water 3 times, place the washed solid in a vacuum drying oven and dry at 70 °C for 12 h to obtain 9# composite filler.

[0070] 2. Application of lignin / fumed silica dual-phase filler in the preparation of rubber composite materials Same as Example 1.

[0071] Example 10: Preparation and application of lignin / fumed silica dual-phase filler The synthesis process in this embodiment is similar to that in Example 1, except that the catalyst is 3% (by mass) dibutyltin dilaurate. 1. Preparation of lignin / fumed silica duplex filler (1) The lignin (phenolic hydroxyl content of 6 mmol / g) was pulverized and passed through a 100-mesh sieve, placed in a vacuum drying oven, and dried at 70 °C for 3 h to obtain lignin powder; (2) Add silica (specific surface area of ​​200 m²) 2 / g) was placed in a muffle furnace and activated at 110 °C for 1.5 h to obtain pretreated silica; (3) Weigh lignin powder and silica at a mass ratio of 1:2, then add the mixed powder to acetone solution and stir thoroughly to obtain a uniformly dispersed mixed suspension; the total mass concentration of lignin and silica in the suspension (i.e., the percentage of total solid mass to total suspension mass) is 15%; (4) Add the catalyst dibutyltin dilaurate (3% of the total mass of lignin powder and fumed silica) to the mixed suspension in step (3), and react at 95 °C for 8 h under nitrogen protection, with continuous stirring (500 rpm). (5) After the reaction is completed, cool to room temperature, filter and collect solid product; wash solid product with ethanol 4 times; wash solid product with water 3 times, place the washed solid in a vacuum drying oven and dry at 70 °C for 12 h to obtain 10# composite filler.

[0072] 2. Application of lignin / fumed silica dual-phase filler in the preparation of rubber composite materials Same as Example 1.

[0073] Example 11: Preparation and application of lignin / fumed silica duplex filler The synthesis process in this embodiment is similar to that in Example 1, except that the total mass concentration of lignin and silica is 10%. 1. Preparation of lignin / fumed silica duplex filler (1) The lignin (phenolic hydroxyl content of 6 mmol / g) was pulverized and passed through a 100-mesh sieve, placed in a vacuum drying oven, and dried at 70 °C for 3 h to obtain lignin powder; (2) Add silica (specific surface area of ​​200 m²) 2 / g) was placed in a muffle furnace and activated at 110 °C for 1.5 h to obtain pretreated silica; (3) Weigh lignin powder and silica at a mass ratio of 1:2, then add the mixed powder to a tetrahydrofuran solution and stir thoroughly to obtain a uniformly dispersed mixed suspension; the total mass concentration of lignin and silica in the suspension (i.e., the percentage of the total mass of solids to the total mass of the suspension) is 10%; (4) Add the catalyst dibutyltin dilaurate (1% of the total mass of lignin powder and silica) to the mixed suspension in step (3), and react at 95 °C for 8 h under nitrogen protection, with continuous stirring (500 rpm). (5) After the reaction is completed, cool to room temperature, filter and collect solid product; wash solid product with ethanol 4 times; wash solid product with water 3 times, place the washed solid in a vacuum drying oven and dry at 70 °C for 12 h to obtain 11# composite filler.

[0074] 2. Application of lignin / fumed silica dual-phase filler in the preparation of rubber composite materials Same as Example 1.

[0075] Example 12: Preparation and application of lignin / fumed silica duplex filler The synthesis process in this embodiment is similar to that in Example 1, except that the total mass concentration of lignin and silica is 20%. 1. Preparation of lignin / fumed silica duplex filler (1) The lignin (phenolic hydroxyl content of 6 mmol / g) was pulverized and passed through a 100-mesh sieve, placed in a vacuum drying oven, and dried at 70 °C for 3 h to obtain lignin powder; (2) Add silica (specific surface area of ​​200 m²) 2 / g) was placed in a muffle furnace and activated at 110 °C for 1.5 h to obtain pretreated silica; (3) Weigh lignin powder and silica at a mass ratio of 1:2, then add the mixed powder to a tetrahydrofuran solution and stir thoroughly to obtain a uniformly dispersed mixed suspension; the total mass concentration of lignin and silica in the suspension (i.e., the percentage of the total mass of solids to the total mass of the suspension) is 20%; (4) Add the catalyst dibutyltin dilaurate (1% of the total mass of lignin powder and silica) to the mixed suspension in step (3), and react at 95 °C for 8 h under nitrogen protection, with continuous stirring (500 rpm). (5) After the reaction is completed, cool to room temperature, filter and collect solid product; wash solid product with ethanol 4 times; wash solid product with water 3 times, place the washed solid in a vacuum drying oven and dry at 70 °C for 12 h to obtain 12# composite filler.

[0076] 2. Application of lignin / fumed silica dual-phase filler in the preparation of rubber composite materials Same as Example 1.

[0077] Comparative Examples 1-3 Meanwhile, to compare the overall performance of the composite fillers prepared in the above embodiments, the following comparative examples are provided. The comparative samples were prepared according to the following formulation: Styrene-butadiene rubber (SBR) 100 phr; sulfur 1.5 phr; accelerator CZ 1.5 phr; accelerator D 0.5 phr; stearic acid 1 phr; zinc oxide 5 phr; silica 40 phr; antioxidant 2 phr. In the comparative design, the antioxidants were 6 PPD, antioxidant 4010NA, and antioxidant BHT.

[0078] Table 4 Preparation of rubber composite materials

[0079] The samples from Examples 1, 2, 5, 6, 8, 10 and Comparative Examples 1, 2, 3 were suspended in an aging chamber at 100 °C for 7 days of accelerated aging testing. The samples were tested before and after the accelerated aging test, according to ISO 37-2005, with a tensile rate of 500 mm / min and a temperature of room temperature. The retention rate of mechanical properties was calculated. The tensile properties and anti-aging properties of each group of samples are shown in the table below.

[0080] Table 5. Sample mechanical property retention rate

[0081] Analysis of the data in the table above shows that the rubber material using this duplex filler exhibits tensile strength superior to or close to that of the comparative example, and its retention rate of tensile strength and elongation at break after aging is similar to that of the comparative example. This demonstrates that it possesses both excellent reinforcing and anti-aging effects, and is expected to replace the traditional combination of silica and chemical antioxidants.

[0082] Comparative Example 4 The synthesis process is similar to that in Example 1, except that the phenolic hydroxyl content in the lignin is 5 mmol / g and 15 mmol / g.

[0083] The results showed that lignin with a phenolic hydroxyl content of 5 mmol / g had a less effective anti-aging effect than lignin with a phenolic hydroxyl content of 6 mmol / g, and the preparation of lignin with a higher phenolic hydroxyl content was relatively more difficult in terms of both technical challenges and economic costs.

[0084] Comparative Example 5 The synthesis process is similar to that in Example 1, except that the mass ratio of lignin to silica is 1:3 or 3:1. The results showed that when the mass ratio was 1:3, its anti-aging performance was worse than that of the mass ratio of 2:1; while when the mass ratio was 3:1, its anti-aging performance was not significantly different from that of the mass ratio of 2:1. Since the mass ratio of 2:1 can meet the requirements, it is more appropriate to choose the mass ratio of 2:1 in order to control costs.

[0085] Comparative Example 6 The synthesis process is similar to that in Example 1, except that the catalyst is replaced with tetrabutyl titanate and zinc stearate.

[0086] The results showed that tetrabutyl titanate (TBTDL) exhibited slightly lower efficiency in catalyzing hydroxyl condensation than DBTDL, with moderate selectivity for both Si-OH and C-OH, requiring higher temperatures (140–160 °C) to function. Zinc stearate (DBTDL) showed significantly lower catalytic activity, poor selectivity for hydroxyl condensation, and required strongly acidic conditions (pH < 3) to be effective. Overall, both catalysts were inferior to dibutyltin dilaurate (DBTDL) in terms of reaction conditions, catalytic efficiency, and selectivity.

[0087] Comparative Example 7 The synthesis process is similar to that in Example 1, except that the temperature of the catalytic reaction is adjusted to 70°C.

[0088] The results showed that the amount of lignin grafted was lower than at 80℃, which may be because the lower temperature affects the grafting reaction.

[0089] Comparative Example 8 This comparative example omits step 1 and directly uses silica and lignin to prepare rubber composite materials: Table 6 Preparation of rubber composite materials

[0090] The results showed that when lignin was directly blended without grafting, the finished product was prone to blooming.

[0091] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A method for preparing a lignin / silica dual phase filler, characterized in that, The method is as follows: (1) uniformly dispersing lignin and white carbon black in a mass ratio of (1:2)~(2:1) into an organic solvent to prepare a mixed suspension; (2) adding dibutyltin dilaurate into the mixed suspension in step (1), and performing catalytic reaction, cooling, filtering, washing, and drying under an inert atmosphere to prepare a dual-phase filler; The phenolic hydroxyl content of the lignin is 6~10 mmol / g; The addition amount of the dibutyltin dilaurate is 0.5%~3% of the total mass of the lignin and the white carbon black.

2. The method of claim 1, wherein, In step (1), the total mass concentration of the lignin and the white carbon black is 10%~20%.

3. The method of claim 1, wherein, In step (1), the specific surface area of the white carbon black is 100-300 m 2 / g; the white carbon black is activated at 100-120°C for 1-2 h.

4. The method of claim 1, wherein, In step (1), the lignin is a powder prepared after being pulverized, sieved, and dried; Preferably, the lignin is pulverized, sieved through a 80~200 mesh sieve, and dried at 60~80℃ for 2~4 h; More preferably, the lignin is pulverized, sieved through a 100~200 mesh sieve, and dried at 70~90℃ for 2~4 h.

5. The method of claim 1, wherein, In step (2), the catalytic reaction is performed at 80~110℃ for 4~12 h; Preferably, the catalytic reaction is performed at 80~100℃ for 8~12 h.

6. The dual-phase filler prepared by the method in any one of claims 1~5.

7. Use of the bi-phase filler according to claim 6 for the preparation of a rubber material, characterized in that, The application is adding the dual-phase filler when preparing a rubber material.

8. A rubber composite material, characterized by, It is made of the following raw materials by mass fraction: olefin rubber: 100 parts; stearic acid: 1~5 parts; accelerator: 1~5 parts; dual-phase filler: 20~40 parts; reinforcing filler: 5~10 parts; vulcanizing agent: 1~3 parts; Optionally, the olefin rubber includes one or more of styrene butadiene rubber, cis-butadiene rubber, isoprene rubber, ethylene propylene rubber, butyl rubber, nitrile rubber, and chlorobutyl rubber; Optionally, the accelerator is one or a mixture of accelerator CZ and accelerator D; Optionally, the vulcanizing agent includes sulfur; Optionally, the reinforcing filler is a mixture of one or both of carbon black and white carbon black.

9. A process for the preparation of the rubber composite material according to claim 8, characterized in that, The method is as follows: plasticizing the olefin rubber at room temperature for 4~8 min; then adding the dual-phase filler and the reinforcing filler, and mixing for 4~8 min with multiple times of turning; then adding the stearic acid and the accelerator, and continuing to mix for 4~8 min with 3~5 times of triangle bag beating; adding the vulcanizing agent, mixing for 2~5 min with 3~5 times of triangle bag beating, and rolling for 3~5 times to obtain a mixed rubber; and molding and vulcanizing the mixed rubber at 160~170℃ and 12~15 MPa to obtain a rubber composite material; Optionally, the olefin rubber includes one or more of styrene butadiene rubber, cis-butadiene rubber, isoprene rubber, ethylene propylene rubber, butyl rubber, nitrile rubber, and chlorobutyl rubber; Optionally, the accelerator is one or a mixture of accelerator CZ and accelerator D; Optionally, the vulcanizing agent includes sulfur; Optionally, the reinforcing filler is a mixture of one or both of carbon black and white carbon black.

10. The use of the method according to any one of claims 1-5, or the biphase filler according to claim 6, or the rubber composite according to claim 8, or the method according to claim 9 in the field of automobile manufacturing, sports goods, building materials, aerospace, medical devices. Optionally, the field of automobile manufacturing includes the preparation of key rubber products such as tires, automobile seals, automobile shock absorbing parts, etc. Optionally, the field of sports goods includes the preparation of sports shoe soles, sports equipment handles. Optionally, the field of building materials includes the preparation of waterproof coiled materials, sealing strips. Optionally, the field of aerospace includes the preparation of airplane tires, seals.

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