A low rolling resistance high abrasion tire tread compound and method of making the same

Abstract

The application provides a low-rolling-resistance high-wear-resistance tire tread rubber and a preparation method thereof, and relates to the technical field of high polymer materials.The low-rolling-resistance high-wear-resistance tire tread rubber comprises a rubber matrix, modified alkali lignin, silicon reinforcing filler, carbon reinforcing filler, vulcanizing agent and other additives.The rubber matrix comprises natural rubber, epoxidized styrene-butadiene rubber and phosphorus-containing styrene-butadiene rubber.The modified alkali lignin is glycidyl methacrylate modified alkali lignin.The silicon reinforcing filler comprises nano-silicon dioxide and silane coupling agent Si-69.The carbon reinforcing filler comprises a mixture of carbon black and argon plasma modified pyrolytic carbon black.The vulcanizing agent is sulfur.The other additives comprise accelerant, zinc oxide, stearic acid, antioxidant and processing oil.The application optimizes the formula and production process of the tire tread rubber, and the prepared rubber has low rolling resistance, high wear resistance and good wet grip performance, has good production safety and has good industrial application prospect.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a low rolling resistance and high wear resistance tire tread compound and its preparation method. Background Technology

[0002] Tire tread compound is a key material that determines tire rolling resistance, wet grip, wear resistance, dynamic heat generation, and service life. Its performance directly affects vehicle fuel economy, driving safety, and tire service life. With the development of energy conservation, emission reduction, and green tires, higher requirements are being placed on the performance of tread compounds.

[0003] Current tire tread compounds mostly use natural rubber, styrene-butadiene rubber, or their blends, reinforced with fillers such as carbon black and silica. Silica is widely used in green tire treads due to its ability to reduce rolling resistance and improve wet grip. However, silica contains a large number of silanol groups on its surface, making it prone to agglomeration through hydrogen bonding. Furthermore, its poor compatibility with non-polar rubber matrices limits its dispersibility in rubber. To improve silica dispersion, silane coupling agents or functionalized rubbers are typically introduced. However, silane coupling agents are prone to side reactions during high-temperature mixing, leading to decreased processing safety. While higher functionality rubbers help enhance the interaction between fillers and rubber, they often increase molecular chain rigidity and raise the glass transition temperature, thus negatively impacting the low-temperature flexibility and dynamic properties of the compound.

[0004] Carbon black, as a traditional tread reinforcing filler, possesses excellent reinforcing and wear-resistant properties, and is particularly suitable for improving the mechanical strength and abrasion resistance of tread compounds. However, single-carbon black systems have limitations in reducing rolling resistance, and high-volume conventional carbon black can lead to increased hysteresis loss in the compound, which is detrimental to the requirements of low heat generation and low energy consumption in tires. In recent years, pyrolytic carbon black has gradually attracted attention due to its resource utilization from waste tires, which has good circular economy value. However, unmodified pyrolytic carbon black generally suffers from insufficient surface activity, uneven structure, and poor dispersion performance. When directly used in high-performance tread compounds, it is often difficult to simultaneously achieve wear resistance, wet grip, and processing stability.

[0005] Therefore, it is of great significance to develop a tire tread compound that can balance low rolling resistance, high wear resistance and good wet grip performance. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a low rolling resistance and high wear resistance tire tread compound and its preparation method, which addresses the shortcomings of the existing technology. The present invention optimizes the formulation and production process of the tire tread compound, and the prepared compound has low rolling resistance, high wear resistance and good wet grip performance, good production safety and good industrial application prospects.

[0007] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0008] In the first aspect, a low rolling resistance and high wear resistance tire tread compound includes a rubber matrix, modified alkali lignin, silicon reinforcing filler, carbon reinforcing filler, vulcanizing agent, and other additives.

[0009] The rubber matrix includes natural rubber and phosphorus-containing styrene-butadiene rubber;

[0010] The modified alkali lignin is glycidyl methacrylate modified alkali lignin.

[0011] The silicon-reinforced filler includes nano-silica and silane coupling agent Si-69;

[0012] The carbon-reinforced filler comprises a mixture of carbon black and argon plasma-modified pyrolytic carbon black;

[0013] The vulcanizing agent is sulfur;

[0014] The other additives include accelerators, zinc oxide, stearic acid, antioxidants, and processing oils.

[0015] Preferably, the preparation process of the epoxidized styrene-butadiene rubber includes: dissolving solution-polymerized styrene-butadiene rubber in toluene to obtain a solution-polymerized styrene-butadiene rubber solution; mixing and stirring formic acid and a 30wt% hydrogen peroxide solution at 0-5℃ for 20-30 min under nitrogen protection to obtain a peroxyformic acid solution; adding the peroxyformic acid solution to the above solution-polymerized styrene-butadiene rubber solution, controlling the amount of formic acid and hydrogen peroxide solution added to be 7-10wt% and 10-15wt% of the mass of solution-polymerized styrene-butadiene rubber, respectively; heating to 40-50℃ under a nitrogen atmosphere and stirring at 300-700 rpm for 4-6 h; cooling to room temperature after the reaction is completed; adjusting the pH of the reaction solution to neutral; pouring the reaction solution into ethanol to precipitate; filtering; washing the precipitate and drying to obtain epoxidized styrene-butadiene rubber.

[0016] Preferably, the preparation of phosphorus-containing styrene-butadiene rubber includes: dissolving solution-polymerized styrene-butadiene rubber in tetrahydrofuran, adding 5-7 wt% of diisobutylphosphine (by weight of the solution-polymerized styrene-butadiene rubber) under nitrogen protection, then adding 1-2 wt% of azobisisobutyronitrile (azobisisobutyronitrile) by weight of the solution-polymerized styrene-butadiene rubber, stirring and reacting at 70-80℃ and 200-300 rpm for 15-20 h, continuing to add 1-2 wt% of azobisisobutyronitrile (azobisisobutyronitrile) by weight of the solution-polymerized styrene-butadiene rubber, reacting for another 15-20 h, cooling to room temperature after the reaction is completed, pouring the reaction solution into ethanol to precipitate, filtering, washing the precipitate, mixing it evenly with 0.1-0.2 wt% of antioxidant 6PPD (by weight of the solution-polymerized styrene-butadiene rubber), and drying to obtain phosphorus-containing styrene-butadiene rubber.

[0017] Preferably, the amounts of each component, by weight, are as follows: 100 parts of rubber matrix, 6-8 parts of modified alkali lignin, 33-120 parts of silicon reinforcing filler, 10-80 parts of carbon reinforcing filler, 1-2 parts of vulcanizing agent, and 17-40.4 parts of other additives.

[0018] Preferably, by weight, the amounts of each component in the rubber matrix are as follows: 20-60 parts of natural rubber, 30-70 parts of epoxidized styrene-butadiene rubber, and 2-15 parts of phosphorus-containing styrene-butadiene rubber.

[0019] Preferably, by weight, the amounts of each component in the silicon-reinforced filler are: 30-110 parts nano-silica and 3-10 parts silane coupling agent Si-69.

[0020] Preferably, by weight, the amounts of each component in the carbon-reinforced filler are as follows: the mass ratio of argon plasma modified pyrolytic carbon black to carbon black is (10-30):(20-50).

[0021] The preparation method of the argon plasma modified pyrolytic carbon black includes:

[0022] (1) Add pyrolytic carbon black to a mixture of ethanol and water, with a volume ratio of ethanol to water of 1:1. Disperse the mixture by ultrasonication at 500W for 30 minutes, filter, precipitate and dry to obtain pretreated pyrolytic carbon black.

[0023] (2) The pretreated pyrolytic carbon black is subjected to argon plasma treatment, with the treatment pressure controlled at 80-100Pa, the power at 100-300W, and the treatment time at 10-20min, to obtain argon plasma modified pyrolytic carbon black.

[0024] Preferably, the amounts of each component in the other additives, by weight, are as follows: 1.0-2.4 parts of accelerator, 3-5 parts of zinc oxide, 1-3 parts of stearic acid, 2-5 parts of antioxidant, and 10-25 parts of processing oil.

[0025] A method for preparing a low rolling resistance and high wear-resistant tire tread compound includes the following steps:

[0026] (1) In an alkaline aqueous solution, alkali lignin reacts with glycidyl methacrylate to obtain modified alkali lignin;

[0027] (2) Dilute the natural latex, then add it to the modified alkali lignin solution and mix to react, thus obtaining the masterbatch;

[0028] (3) Argon plasma modified pyrolytic carbon black is premixed with carbon black to obtain carbon reinforced filler;

[0029] (4) Premix epoxidized styrene-butadiene rubber, phosphorus-containing styrene-butadiene rubber, masterbatch, nano silica, silane coupling agent Si-69, processing oil, and some carbon reinforcing filler; then add the remaining carbon reinforcing filler, zinc oxide, stearic acid, antioxidant, sulfur and accelerator for further mixing; finally vulcanize and mold to obtain tire tread compound.

[0030] Preferably, in step (1), the process of reacting alkali lignin with glycidyl methacrylate in an alkaline aqueous solution to obtain modified alkali lignin includes:

[0031] Alkali lignin was dissolved in deionized water, and then a 1M sodium hydroxide solution was added to adjust the pH to 13-13.5. The temperature was raised to 70-85℃, and then glycidyl methacrylate was slowly added. After the addition was completed, the temperature was maintained at 300-800 rpm for 3-6 hours. After the reaction was completed, the temperature was lowered to below 40℃, and the pH of the system was adjusted to 2-4 to precipitate. The precipitate was filtered, washed, and dried to obtain modified alkali lignin.

[0032] Preferably, the preparation process of the masterbatch includes:

[0033] Dilute natural latex to a solid content of 15-25 wt%, add ammonia to adjust the pH to 9.5-11.5, and then slowly add a modified alkali lignin solution with a concentration of 2-6 wt% at 300-800 rpm. After the addition is complete, continue stirring for 30-90 min. Under a nitrogen atmosphere and at a temperature of 25-40℃, add 0.03-0.25 wt% of tert-butyl hydroperoxide and 0.02-0.2 wt% of sodium formaldehyde sulfoxylate by weight of natural rubber. React for 0.5-3 h, adjust the pH of the system to 4-5 for coagulation, wash and dry to obtain the masterbatch.

[0034] Preferably, in step (4), the premixing conditions include: a rotation speed of 40-70 rpm, a filling coefficient of 0.65-0.75, an initial temperature of 80-100℃, a mixing time of 4-8 min, and a discharge temperature of 150-160℃.

[0035] Preferably, in step (4), the conditions for re-mixing include: initial temperature ≤70℃, discharge temperature ≤110℃, rotor speed 20-35rpm, mixing time: 2-4min, filling coefficient 0.6-0.7; after re-mixing, the sheet is rolled out on an open mill at a roller temperature of 40-60℃ and a roller gap of 2-3mm, passed through a thin mill 3-6 times, and finally placed at room temperature for ≥12h.

[0036] Preferably, in step (4), the vulcanization conditions include: vulcanization temperature of 150-160℃, vulcanization time of 10-30min, and vulcanization pressure of 10-15MPa.

[0037] By adopting the above technical solution, the present invention has at least the following beneficial effects:

[0038] 1. This invention provides a low rolling resistance and high wear resistance tire tread compound, which uses natural rubber, epoxidized styrene-butadiene rubber and phosphorus-containing styrene-butadiene rubber to form a composite rubber matrix. Natural rubber provides excellent elasticity and mechanical strength, epoxidized styrene-butadiene rubber enhances the interaction between rubber molecular chains and silica, and phosphorus-containing styrene-butadiene rubber further improves the filler-rubber interface bonding and vulcanization network structure. The tire tread compound prepared by the compounding of the above three types of rubber matrices not only has good wet grip performance, but also excellent rolling resistance and wear resistance.

[0039] 2. This invention uses glycidyl methacrylate to modify alkali lignin. The resulting modified alkali lignin is used as a reactive bio-based component. Through the introduced reactive groups, the modified alkali lignin can not only improve its dispersion in the rubber matrix, but also form a stronger interfacial interaction with the rubber matrix during subsequent mixing and vulcanization. This leads to the construction of a lignin-rubber covalent reinforcement network, thereby reducing interfacial defects, improving reinforcement efficiency, and enhancing the mechanical properties and dynamic stability of the rubber compound.

[0040] 3. This invention uses nano-silica and silane coupling agent Si-69 as silicon-reinforcing fillers, and combines them with the polarity regulating effect of epoxidized styrene-butadiene rubber, which helps to weaken the agglomeration between fillers, enhance the uniformity of filler dispersion in the rubber matrix, and improve the interfacial bonding between fillers and rubber; thereby effectively reducing dynamic heat generation and hysteresis loss, which helps to reduce the rolling resistance of the tread compound.

[0041] 4. This invention uses carbon black and argon plasma-modified pyrolytic carbon black to form a carbon-reinforced filler. Argon plasma modification can improve the surface activity and interfacial interaction ability of pyrolytic carbon black. When combined with conventional carbon black, it can form a more rationally structured hybrid carbon reinforcement network. This network helps to improve the reinforcement effect, wear resistance and friction interface stability of the filler, thereby improving the performance of the tread compound under complex working conditions.

[0042] 5. This invention synergistically constructs a multi-level composite reinforcement structure through the synergistic construction of a modified alkali lignin network, a low-heat-generating network formed by silicon-reinforced fillers and the matrix, and a wear-resistant network formed by carbon-reinforced fillers and the matrix. This multi-level composite reinforcement structure can jointly regulate the rubber compound properties from three aspects: molecular chains, interface layers, and filler networks, thereby effectively improving the low rolling resistance, high wear resistance, and wet grip performance of the tread compound. Furthermore, this invention introduces modified alkali lignin and argon plasma-modified pyrolytic carbon black into the tread compound, effectively reducing the preparation cost of the tire tread compound while ensuring improved compound performance.

[0043] 6. In preparing tire tread compound, the present invention adopts a segmented mixing process. First, pre-mixing is carried out to fully disperse the rubber matrix, silica, silane coupling agent Si-69 and some carbon reinforcing fillers and complete the main interfacial function. Then, sulfur, accelerator and other additives are added at a lower temperature for re-mixing. The above process helps to avoid the vulcanization system from participating in the reaction in advance at high temperature, reduce the risk of scorching, improve the mixing stability and processing safety, and at the same time help to ensure the uniformity of the final network structure.

[0044] 7. In summary, the tire tread compound prepared by this invention not only has high mechanical strength, but also excellent wear resistance, low rolling resistance, and grip performance on wet and slippery roads. It is suitable for the preparation of tire treads with low energy consumption, high durability, and high safety, and has good prospects for industrial application. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0046] Figure 1 The loss factor (tanδ)-temperature curves of the rubber compounds in Examples 1-3 and Comparative Examples 1-4 are shown. Detailed Implementation

[0047] 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.

[0048] 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.

[0049] The properties of some raw materials in the following examples and comparative examples are as follows. Unless otherwise specified, other raw materials are all commercially available products in the field. Example 1

[0050] A low rolling resistance and high wear resistance tire tread compound, by weight, comprises 40 parts natural rubber, 55 parts epoxidized styrene-butadiene rubber, 5 parts phosphorus-containing styrene-butadiene rubber, 6 parts modified alkali lignin, 75 parts nano silica, 6 parts silane coupling agent Si-69, 35 parts carbon black N330, 10 parts argon plasma modified pyrolytic carbon black, 1.5 parts sulfur, 1.2 parts accelerator TBBS, 0.4 parts accelerator DPG, 4 parts zinc oxide, 2 parts stearic acid, 2 parts antioxidant 6PPD, 1.5 parts antioxidant TMQ, and 15 parts processing oil TDAE.

[0051] Its preparation method includes the following steps:

[0052] (1) Preparation of epoxidized styrene-butadiene rubber:

[0053] 1000g of solution-polymerized styrene-butadiene rubber (brand name 2466, product of TSRC Corporation) was dissolved in 4L of toluene and stirred at 40°C for 2h to obtain a solution-polymerized styrene-butadiene rubber solution. Under nitrogen protection, 80g of formic acid and 120g of 30wt% hydrogen peroxide solution were mixed and stirred at 5°C for 25min to obtain a performic acid solution. The performic acid solution was slowly added dropwise to the solution-polymerized styrene-butadiene rubber solution, and the temperature was raised to 45°C and stirred at 500rpm for 5h. After the reaction was completed, the solution was cooled to room temperature, neutralized with sodium bicarbonate, and the reaction solution was poured into 10L of ethanol to precipitate. The precipitate was filtered, washed with ethanol, and dried under vacuum at 60°C for 24h to obtain epoxidized styrene-butadiene rubber.

[0054] (2) Preparation of phosphorus-containing styrene-butadiene rubber:

[0055] 500g of solution-polymerized styrene-butadiene rubber (brand name 2466, product of TSRC Corporation) was dissolved in 2L of tetrahydrofuran. Under nitrogen protection, 30g of diisobutylphosphine and 7g of azobisisobutyronitrile were added, and the reaction was carried out at 75℃ and 250rpm for 18h. Then, 7g of azobisisobutyronitrile was added, and the reaction was continued for another 18h. After the reaction was completed, the mixture was cooled to room temperature, and the reaction solution was poured into 5L of ethanol to precipitate the precipitate. The precipitate was filtered, washed, and mixed with 0.75g of antioxidant 6PPD. The mixture was then dried under vacuum at 60℃ to obtain phosphorus-containing styrene-butadiene rubber.

[0056] (3) Preparation of modified alkali lignin:

[0057] 66g of alkali lignin (200 mesh, product of Xinyi Feihuang Chemical Co., Ltd.) was dissolved in 250mL of deionized water. The pH of the system was adjusted to 13 with 1M NaOH. The temperature was raised to 80℃, and 14.2g of glycidyl methacrylate was slowly added dropwise. The reaction was carried out for 5h with stirring at 500rpm. The temperature was lowered to below 40℃, and the pH of the system was adjusted to 3 with hydrochloric acid. The precipitate was collected, filtered, washed with ethanol, and dried at 80℃ to obtain modified alkali lignin.

[0058] (4) Preparation of argon plasma modified pyrolytic carbon black:

[0059] Pyrolytic carbon black (grade EN660, product of Henan Zhumadian Yikesida Renewable Resources Co., Ltd.) was added to a mixture of ethanol and water (volume ratio of ethanol to water is 1:1), ultrasonically dispersed at 500W power for 30min, filtered, precipitated and dried to obtain pretreated pyrolytic carbon black; 100g of pretreated pyrolytic carbon black was evenly spread in a quartz boat, the quartz boat was placed in a plasma reaction chamber, the pressure in the reaction chamber was reduced to 50Pa by vacuuming, and then argon gas was introduced into the reaction chamber at a rate of 50mL / min to stabilize the pressure in the reaction chamber to 80Pa. It was treated at 200W power for 20min to obtain argon plasma modified pyrolytic carbon black;

[0060] (5) Preparation of masterbatch:

[0061] Natural latex (60wt% solid natural rubber content, product of Hainan Natural Rubber Industry Group Co., Ltd.) was diluted to a solid content of 20wt%, and the pH was adjusted to 10.5 with ammonia. A 4wt% modified alkali lignin solution was slowly added while stirring at 500 rpm, and stirring was continued for 60 min. Under a nitrogen atmosphere, 0.15wt% tert-butyl hydroperoxide (0.1wt% of the natural rubber mass) and sodium formaldehyde sulfoxylate (0.1wt% of the natural rubber mass) were added, and the reaction was carried out at 30℃ for 2 h. The pH of the system was adjusted to 4.5 to coagulate, filtered, washed, and dried at 60℃ to obtain the masterbatch.

[0062] (6) Rubber compounding:

[0063] Add the following components sequentially to a mixer: epoxidized styrene-butadiene rubber, phosphorus-containing styrene-butadiene rubber, masterbatch, nano-silica (average particle size 7nm, Sigma), silane coupling agent Si-69, processing oil TDAE (Vivatec 500, product of Xinda Yang (Ningbo) Co., Ltd.), carbon black N330 (product of Hebei Longxing Chemical Co., Ltd.), and half the mass of a mixture of argon plasma modified pyrolysis carbon black. Perform one mixing operation (filling factor 0.7, speed 60). The mixture was first stirred at 155℃ for 6 minutes (initial temperature 90℃), and then added to a mixture of remaining carbon black N330 and argon plasma modified pyrolytic carbon black, zinc oxide, stearic acid, sulfur, accelerator TBBS, accelerator DPG, antioxidant 6PPD, and antioxidant TMQ for a second mixing (initial temperature 60℃, speed 30 rpm, filling factor 0.6), and stirred for 3 minutes, with a discharge temperature of 105℃. The mixture was then finalized on an open mill (roller temperature 50℃, roll gap 2.5 mm), passed through a thin mill 5 times, and left to stand at room temperature for 24 hours. Finally, it was vulcanized on a flat vulcanizing mill at 155℃ and 12MPa for 15 minutes to obtain a low rolling resistance and high wear resistance tire tread compound. Example 2

[0064] The difference between this example and Example 1 is that: 30 parts of carbon black N330, 20 parts of argon plasma modified pyrolytic carbon black, and other conditions are the same as in Example 1. Example 3

[0065] The difference between this example and Example 1 is that: 50 parts of natural rubber, 45 parts of epoxidized styrene-butadiene rubber, and 5 parts of phosphorus-containing styrene-butadiene rubber are used, while other conditions are the same as in Example 1. Comparative Example 1

[0066] The difference between this example and Example 1 is that an equal amount of epoxidized styrene-butadiene rubber is used instead of phosphorus-containing styrene-butadiene rubber, while the other operations are the same as in Example 1. Comparative Example 2

[0067] The difference between this example and Example 1 is that the modified alkali lignin is not pre-mixed with natural rubber to prepare the masterbatch, but is added separately in a single mixing process. Other operations are the same as in Example 1. Comparative Example 3

[0068] The difference between this example and Example 1 is that the carbon-reinforced filler only includes carbon black N330, and argon plasma modified pyrolytic carbon black is not added. Other operations are the same as in Example 1. Comparative Example 4

[0069] The difference between this example and Example 1 is that during the internal mixing process, the epoxidized styrene-butadiene rubber, phosphorus-containing styrene-butadiene rubber, masterbatch, nano silica, silane coupling agent Si-69, processing oil TDAE, a mixture of carbon black N330 and argon plasma modified pyrolytic carbon black, zinc oxide, stearic acid, sulfur, accelerator TBBS, accelerator DPG, antioxidant 6PPD, and antioxidant TMQ are directly mixed and subjected to one internal mixing. The internal mixing conditions are the same as those in the example, and other operations are the same as in Example 1.

[0070] The performance of the tire tread compounds prepared in the above embodiments and comparative examples will be tested below.

[0071] I. Physical and mechanical properties:

[0072] 1. Tensile strength: Tested according to GB / T528-2009 standard, using an Instron 5967 universal testing machine, tensile speed 500 mm / min, test temperature 23℃±2℃.

[0073] 2. Tear strength: Tested according to GB / T529-2008 standard, using right-angled specimens, tensile speed 500mm / min.

[0074] 3. Shore A hardness: Tested according to GB / T531.1-2008 standard, using an LX-A Shore hardness tester, and measured after being placed at room temperature for 24 hours.

[0075] 4. Rebound value (impact rebound rate): Tested according to GB / T1681-2009 standard, using Zwick5101 rebound testing machine, pendulum impact energy 0.5J.

[0076] The test results are shown in Table 1.

[0077] Table 1

[0078]

[0079] As can be seen from the test results in Table 1, compared with the comparative examples, the tire tread compounds prepared in Examples 1-3 of the present invention show outstanding performance in terms of tensile strength, tear strength and resilience.

[0080] Among them, the tensile strength of Examples 1-3 reached 21.8-23.1 MPa, which was significantly higher than that of Comparative Examples 1-4; the tear strength also increased from 46.5-54.1 kN / m in the comparative examples to 56.9-60.2 kN / m. These results indicate that the present invention, by constructing a composite rubber matrix using natural rubber, epoxidized styrene-butadiene rubber, and phosphorus-containing styrene-butadiene rubber, and introducing a modified alkali lignin and carbon-reinforced filler composite network, can effectively enhance the interfacial interaction between the filler and the rubber matrix, thereby forming a more stable reinforcing structure and significantly improving the mechanical properties of the rubber compound.

[0081] The rebound values ​​of Examples 1-3 were 47%-49%, higher than the comparative examples, indicating that the rubber compounds in the embodiments of the present invention have stronger elastic recovery capabilities and lower hysteresis loss, which is beneficial for reducing energy loss of the tire during driving. Furthermore, the Shore A hardness of each embodiment was 70-72HA, which is basically consistent with the hardness level of conventional tread rubber compounds, indicating that the present invention improves the mechanical properties of the rubber compound without adversely affecting its processing and performance.

[0082] Compared with the examples, the mechanical properties of Comparative Example 1, which replaced the phosphorus-containing styrene-butadiene rubber with ordinary epoxidized styrene-butadiene rubber, decreased significantly, indicating that the phosphorus-containing functional groups in the rubber matrix help to enhance the interfacial bonding between the filler and the rubber. Comparative Example 2, which did not use modified alkali lignin pre-made masterbatch, also showed a further decrease in mechanical properties, indicating that the introduction of modified alkali lignin into the matrix through masterbatch can significantly improve its dispersion state in the rubber matrix and enhance the reinforcing effect. Comparative Example 4, which used a one-time internal mixing process, had the lowest overall performance, indicating that the segmented mixing process of the present invention is beneficial for constructing a more uniform and stable reinforcing network structure, thereby improving the performance of the tire tread compound.

[0083] II. Wear resistance:

[0084] Akron abrasion: Tested according to GB / T1689-2014 using a GT-7012-A Akron abrasion testing machine, with a load of 26.7 N and a stroke of 1.61 km. Volumetric loss (cm³) was recorded. 3 / 1.61km).

[0085] The above tests are shown in Table 2.

[0086] Table 2

[0087]

[0088] As can be seen from the test results in Table 2, the Akron abrasion loss of the tread compound prepared in the embodiments of the present invention is significantly lower than that of the comparative examples, exhibiting superior wear resistance. Specifically, the Akron abrasion loss of Examples 1-3 is 0.16-0.19 cm³ / 1.61 km, while that of Comparative Examples 1-4 is 0.24-0.33 cm³ / 1.61 km. This result indicates that the present invention, by constructing a composite carbon-reinforced network through carbon black and argon plasma modification of pyrolytic carbon black, significantly improves the reinforcing efficiency and structural stability of the filler. Specifically, argon plasma modification can increase the active sites on the surface of pyrolytic carbon black, making it easier to form interfacial interactions with rubber molecular chains, thereby enhancing the bonding strength between the filler and the rubber and improving the wear resistance of the compound during friction.

[0089] Compared with the examples, Comparative Example 3, which only used carbon black as a carbon-reinforcing filler, had a significantly higher abrasion rate than the examples, indicating that the introduction of argon plasma-modified pyrolytic carbon black can further optimize the carbon filler network structure and improve the abrasion resistance of the rubber compound. In Comparative Example 2, the lack of introduction of modified alkali lignin through masterbatch resulted in poor filler dispersibility and interfacial bonding, leading to a large abrasion rate. In Comparative Example 4, the abrasion rate was the highest when a one-time mixing process was used, indicating that an unreasonable mixing process can lead to an uneven filler network structure, thereby reducing the abrasion resistance of the rubber compound.

[0090] III. Dynamic Mechanical Properties:

[0091] (1) Testing equipment and standards: TAQ800 dynamic mechanical analyzer; testing was conducted in accordance with GB / T9870.2-2008 standard;

[0092] (2) Test mode: tensile mode, frequency 10Hz, heating rate 3℃ / min, temperature range -80℃~100℃, dynamic strain 0.5%;

[0093] (3) Evaluation indicators:

[0094] The tanδ value at 0℃: characterizes the anti-slip performance; the higher the value, the better the grip on wet surfaces.

[0095] The tanδ value at 60℃: characterizes rolling resistance. The lower the value, the smaller the rolling resistance and the better the energy saving effect.

[0096] The loss factor (tanδ)-temperature curves of the examples and comparative rubber compounds are shown below. Figure 1 As shown.

[0097] from Figure 1It can be seen that the tanδ value of the tread compound prepared in the embodiments of the present invention is significantly higher than that of the comparative examples at 0℃, while the tanδ value at 60℃ is significantly lower than that of the comparative examples, indicating that the compound has both good wet grip performance and low rolling resistance. Specifically, the tanδ value of the embodiments at 0℃ is higher than that of the comparative examples, indicating that the compound of the present invention has a higher energy loss capacity under low temperature conditions, thereby improving the grip performance of the tire on wet and slippery roads; while at 60℃, the tanδ values ​​of Examples 1-3 are significantly lower than those of the comparative examples, indicating that the compound of the embodiments has lower hysteresis loss under high temperature driving conditions, which is beneficial to reducing tire rolling resistance and reducing energy consumption.

[0098] In summary, on the one hand, the epoxy styrene-butadiene rubber and nano-silica in this invention form a stronger interfacial interaction, which helps to reduce filler agglomeration and dynamic heat generation; on the other hand, the modified alkali lignin in this invention forms a stable interfacial bonding network with the rubber matrix, while the hybrid carbon-reinforced network formed by carbon black and argon plasma-modified pyrolytic carbon black can effectively regulate the filler structure, thereby simultaneously achieving low rolling resistance and high wet grip performance of the rubber compound.

[0099] IV. Processing Safety:

[0100] 1. Mooney viscosity: Tested according to GB / T1232.1-2016, using a Wallace H17 Mooney viscometer, test temperature 100℃, preheat for 1 min, test for 4 min, and record the ML(1+4) value at 100℃.

[0101] 2. Scorch time: Tested according to GB / T1233-2008, test temperature 120℃, record the time required for Mooney viscosity to rise by 5 units, i.e. t5.

[0102] The test results are shown in Table 3.

[0103] Table 3

[0104]

[0105] As can be seen from the test results in Table 3, the tread compounds prepared in Examples 1-3 of this invention have moderate Mooney viscosity and a relatively long scorch time, demonstrating good processing safety. Specifically, the Mooney viscosity of Examples 1-3 is 66-70, while the scorch time t5 is 17.8-19.2 min, significantly higher than that of the comparative examples; this indicates that the rubber compounds of this invention have good processing stability during mixing and processing, and are less prone to premature scorch.

[0106] Compared with the examples, in Comparative Example 2, the modified alkali lignin was not added through the masterbatch, resulting in uneven dispersion of fillers and increased system viscosity, with a Mooney viscosity of 78. At the same time, the scorch time was significantly shortened. In Comparative Example 4, when a single internal mixing method was used, the Mooney viscosity was the highest and the scorch time was the shortest. This indicates that adding the vulcanization system directly at the high temperature stage can easily cause premature reaction, thereby reducing the processing safety of the rubber compound.

[0107] Therefore, this invention employs a segmented mixing process, which allows the filler and rubber matrix to be fully dispersed and form an interface at a high temperature, and then the vulcanization system is added at a lower temperature, thereby effectively avoiding the premature participation of the vulcanization system in the reaction and improving the mixing stability and processing safety.

[0108] 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 low rolling resistance and high wear resistance tire tread compound, characterized in that, Includes rubber matrix, modified alkali lignin, silicon-reinforced filler, carbon-reinforced filler, vulcanizing agent, and other additives; The rubber matrix includes natural rubber, epoxidized styrene-butadiene rubber, and phosphorus-containing styrene-butadiene rubber; The modified alkali lignin is glycidyl methacrylate modified alkali lignin. The silicon-reinforced filler includes nano-silica and silane coupling agent Si-69; The carbon-reinforced filler comprises a mixture of carbon black and argon plasma-modified pyrolytic carbon black; The vulcanizing agent is sulfur; The other additives include accelerators, zinc oxide, stearic acid, antioxidants, and processing oils; Its preparation method includes the following steps: (1) In an alkaline aqueous solution, alkali lignin reacts with glycidyl methacrylate to obtain modified alkali lignin; (2) Dilute the natural latex and then add the modified alkali lignin solution to mix and react to obtain the masterbatch; the natural latex contains 60 wt% solid natural rubber and is a product of Hainan Natural Rubber Industry Group Co., Ltd. (3) Add pyrolytic carbon black to a mixture of ethanol and water at a volume ratio of 1:1, ultrasonically disperse at 500W for 30min, filter, precipitate and dry to obtain pretreated pyrolytic carbon black; treat the pretreated pyrolytic carbon black with argon plasma, control the treatment pressure at 80-100Pa, the power at 100-300W, and the treatment time at 10-20min to obtain argon plasma modified pyrolytic carbon black; premix the argon plasma modified pyrolytic carbon black with carbon black to obtain carbon reinforced filler; (4) Premix epoxidized styrene-butadiene rubber, phosphorus-containing styrene-butadiene rubber, masterbatch, nano silica, silane coupling agent Si-69, processing oil, and some carbon reinforcing filler; then add the remaining carbon reinforcing filler, zinc oxide, stearic acid, antioxidant, sulfur and accelerator for further mixing; finally vulcanize and mold to obtain tire tread compound.

2. The low rolling resistance and high wear resistance tire tread compound according to claim 1, characterized in that, The preparation process of the epoxidized styrene-butadiene rubber includes: dissolving solution-polymerized styrene-butadiene rubber in toluene to obtain a solution-polymerized styrene-butadiene rubber solution; mixing and stirring formic acid and a 30wt% hydrogen peroxide solution at 0-5℃ for 20-30 min under nitrogen protection to obtain a performic acid solution; adding the performic acid solution to the above solution-polymerized styrene-butadiene rubber solution, controlling the amount of formic acid and hydrogen peroxide solution added to be 7-10wt% and 10-15wt% of the mass of solution-polymerized styrene-butadiene rubber, respectively; heating to 40-50℃ under nitrogen atmosphere and stirring at 300-700 rpm for 4-6 h; cooling to room temperature after the reaction is completed; adjusting the pH of the reaction solution to neutral; pouring the reaction solution into ethanol to precipitate; filtering; washing the precipitate and drying to obtain epoxidized styrene-butadiene rubber.

3. The low rolling resistance and high wear resistance tire tread compound according to claim 1, characterized in that, The preparation of phosphorus-containing styrene-butadiene rubber includes: dissolving solution-polymerized styrene-butadiene rubber in tetrahydrofuran, adding 5-7 wt% of diisobutylphosphine (by weight of the solution-polymerized styrene-butadiene rubber) under nitrogen protection, then adding 1-2 wt% of azobisisobutyronitrile (azobisisobutyronitrile) by weight of the solution-polymerized styrene-butadiene rubber, stirring and reacting at 70-80℃ and 200-300 rpm for 15-20 h, continuing to add 1-2 wt% of azobisisobutyronitrile (azobisisobutyronitrile) by weight of the solution-polymerized styrene-butadiene rubber, reacting for another 15-20 h, cooling to room temperature after the reaction is completed, pouring the reaction solution into ethanol to precipitate, filtering, washing the precipitate, mixing it evenly with 0.1-0.2 wt% of antioxidant 6PPD (by weight of the solution-polymerized styrene-butadiene rubber), and drying to obtain phosphorus-containing styrene-butadiene rubber.

4. The low rolling resistance and high wear resistance tire tread compound according to claim 1, characterized in that, By weight, the amounts of each component are as follows: 100 parts of rubber matrix, 33-120 parts of silicon reinforcing filler, 6-8 parts of modified alkali lignin; 10-80 parts of carbon reinforcing filler, 1-2 parts of vulcanizing agent, and 17-40.4 parts of other additives. The amounts of each component in the rubber matrix, by weight, are as follows: 20-60 parts of natural rubber, 30-70 parts of epoxidized styrene-butadiene rubber, and 2-15 parts of phosphorus-containing styrene-butadiene rubber. And / or the amounts of each component in the silicon-reinforced filler are: 30-110 parts nano silica and 3-10 parts silane coupling agent Si-69; And / or the amounts of each component in the carbon-reinforced filler are as follows: the mass ratio of argon plasma modified pyrolytic carbon black to carbon black is (10-30): (20-50); The amounts of each component in the other additives and / or the other additives are as follows: accelerator 1.0-2.4 parts, zinc oxide 3-5 parts, stearic acid 1-3 parts, antioxidant 2-5 parts, and processing oil 10-25 parts.

5. The low rolling resistance and high wear resistance tire tread compound according to claim 1, characterized in that, In step (1), the process of reacting alkali lignin with glycidyl methacrylate in an alkaline aqueous solution to obtain modified alkali lignin includes: Alkali lignin was dissolved in deionized water, and then a 1M sodium hydroxide solution was added to adjust the pH to 13-13.

5. The temperature was raised to 70-85℃, and then glycidyl methacrylate was slowly added. After the addition was completed, the temperature was maintained at 300-800 rpm for 3-6 hours. After the reaction was completed, the temperature was lowered to below 40℃, and the pH of the system was adjusted to 2-4 to precipitate. The precipitate was filtered, washed, and dried to obtain modified alkali lignin.

6. The low rolling resistance and high wear resistance tire tread compound according to claim 1, characterized in that, In step (2), the preparation process of the masterbatch includes: Dilute natural latex to a solid content of 15-25 wt%, add ammonia to adjust the pH to 9.5-11.5, and then slowly add a modified alkali lignin solution with a concentration of 2-6 wt% at 300-800 rpm. After the addition is complete, continue stirring for 30-90 min. Under a nitrogen atmosphere and at a temperature of 25-40℃, add 0.03-0.25 wt% of tert-butyl hydroperoxide and 0.02-0.2 wt% of sodium formaldehyde sulfoxylate by weight of natural rubber. React for 0.5-3 h, adjust the pH of the system to 4-5 for coagulation, wash and dry to obtain the masterbatch.

7. The low rolling resistance and high wear resistance tire tread compound according to claim 1, characterized in that, In step (4), the premixing conditions include: rotation speed of 40-70 rpm, filling coefficient of 0.65-0.75, initial temperature of 80-100℃, mixing time of 4-8 min, and discharge temperature of 150-160℃.

8. The low rolling resistance and high wear resistance tire tread compound according to claim 1, characterized in that, In step (4), the conditions for re-mixing include: initial temperature ≤70℃, discharge temperature ≤110℃, rotor speed 20-35rpm, mixing time: 2-4min, filling coefficient 0.6-0.7; after re-mixing, the sheet is rolled out on an open mill at a roller temperature of 40-60℃ and a roller gap of 2-3mm, passed through a thin mill 3-6 times, and finally placed at room temperature for ≥12h.

9. The low rolling resistance and high wear resistance tire tread compound according to claim 1, characterized in that, In step (4), the vulcanization conditions include: vulcanization temperature of 150-160℃, vulcanization time of 10-30min, and vulcanization pressure of 10-15MPa.

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