Solid tire tread rubber material with high tear resistance and preparation method thereof

Abstract

The invention discloses a solid tire tread rubber material with high tear resistance and a preparation method thereof, and belongs to the technical field of modified rubber. According to the rubber material, a rubber matrix serves as a matrix, a carbon nano tube is creatively adopted to be compounded with a modification additive, and a three-dimensional reinforced network structure is prepared through a mechanochemical grinding and gradient pyrolysis technology. The formula system comprises carbon black N330, white carbon black, a silane coupling agent and a performance additive, and the interface bonding strength is synergistically improved. According to the preparation process, a three-step gradient mixing technology is combined with two-stage vulcanization, so that uniform dispersion of the filler and optimization of a cross-linked network are realized. Tests show that compared with a traditional formula, the tear strength of the rubber material is improved by more than 40%, the dynamic heat generation is reduced by 35%, the abrasion loss is reduced by 28%, meanwhile, the Shore A hardness is kept at 65 + / -3, and the problem of tread tear failure under the high-load working condition is effectively solved. The technology has the advantages of process feasibility and cost, and is suitable for manufacturing solid tires in the fields of industrial vehicles, harbor machinery and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of modified rubber, and in particular relates to a solid tire tread rubber material with high tear resistance and a preparation method thereof. Background Art

[0002] As an important part of automobiles, the performance of tires is directly related to the safety, comfort and economy of vehicles. Solid tires have unique structural characteristics and do not contain pneumatic inner tubes. They are not easy to blow out and are puncture-resistant. Therefore, they are widely used in certain specific occasions, such as industrial vehicles, construction machinery, forklifts and port transportation equipment. Compared with pneumatic tires, solid tires are used more frequently under high loads and harsh environments, so higher requirements are placed on the performance of their tread rubber. As the part of the tire that is in direct contact with the ground, the performance of the tread rubber directly determines the service life, wear resistance and safety of the tire. Among them, tear resistance is one of the key indicators of solid tire tread rubber. Especially under high loads, high-speed operation or complex road conditions, if the tread rubber is not tear-resistant enough, it is easy to tear, crack or even peel off in blocks, resulting in premature failure of the tire, increasing the cost of use and bringing safety hazards.

[0003] Traditional solid tire tread rubber usually uses natural rubber as the main matrix material. It is widely used in rubber products because of its excellent elasticity, high tensile strength and good processing performance. In order to further improve the performance, synthetic rubbers such as styrene-butadiene rubber and butadiene rubber are also often introduced into the formula to improve wear resistance and aging resistance. In terms of reinforcement system, carbon black, as the most commonly used reinforcing filler, is widely used because of its low cost and ability to significantly improve the strength and wear resistance of rubber. In addition, white carbon black, as another important reinforcing filler, can further improve the wet and slippery performance and wear resistance of the rubber by using it in combination with a silane coupling agent. For example, in the prior art, the addition of carbon black and white carbon black can enhance the mechanical properties of the rubber matrix through physical filling and chemical bonding. However, although these traditional formulas have improved the comprehensive performance of the tread rubber to a certain extent, its tear resistance is still significantly insufficient, especially under extreme conditions of use, cracks are easy to expand, resulting in reduced tire durability.

[0004] In order to solve this problem, researchers have conducted a lot of research on the tear resistance of solid tire tread rubber and proposed a variety of improvement schemes. A common method is to improve the tear resistance of the rubber by optimizing the selection and modification of reinforcing fillers. For example, patent document CN102634089A discloses a tire tread rubber, which significantly improves the anti-skid performance and wear resistance of the rubber by introducing highly dispersed silica and combining it with a silane coupling agent. This technology utilizes the high specific surface area of ​​silica and the interfacial modification effect of the silane coupling agent to enhance the bonding force between the filler and the rubber matrix. However, the formula of this patent has limited effect on improving the tear resistance, and test data show that its tear strength is still difficult to meet the needs of high-load solid tires. In addition, although the addition of highly dispersed silica improves some performance, it also increases processing difficulty and production cost, limiting its promotion in industrial production.

[0005] In recent years, with the rapid development of nanotechnology and polymer materials science, some new nanomaterials have been introduced into rubber composites in order to significantly improve the performance of tread rubber. Materials such as nanoclay, carbon nanotubes and graphene have become research hotspots due to their excellent mechanical properties and unique structural characteristics. For example, studies have shown that the addition of a small amount of graphene can significantly improve the tensile strength, modulus and tear resistance of rubber. As a two-dimensional nanomaterial, graphene has an extremely high specific surface area and excellent thermal conductivity. It can form a network structure in the rubber matrix, disperse external forces and inhibit crack propagation. However, graphene has poor dispersibility in rubber and is prone to agglomeration, resulting in unstable performance improvement. In addition, the high production cost and complex preparation process of graphene limit its large-scale application in solid tire tread rubber. Similarly, although carbon nanotubes also have excellent reinforcement effects, their high winding characteristics make it difficult to disperse evenly, difficult to process, and not cost-effective.

[0006] In summary, the prior art has made some progress in improving the tear resistance of solid tire tread rubber, but it still faces many challenges. First, the tear resistance of traditional reinforcing fillers and rubber blending technology is limited, and it is difficult to meet the use requirements under high load and harsh environment. Secondly, although the new nanomaterials have significant enhancement potential, their poor dispersibility and high cost limit their industrial application. Finally, although the optimization of the vulcanization system can improve some properties, it has limited effect on the breakthrough of tear resistance, and the process complexity increases. Therefore, the development of a solid tire tread rubber with high tear resistance, low cost and easy processing and its preparation method not only has important theoretical research value, but also has broad practical application prospects. It is in this context that the present invention proposes a new solution to the shortcomings of the prior art. By optimizing the rubber matrix, reinforcing fillers and vulcanization system, and introducing a new modifier, it aims to significantly improve the tear resistance of the solid tire tread rubber, while maintaining good processing performance and comprehensive mechanical properties, providing a new technical path for the performance upgrade of solid tires. Summary of the invention

[0007] Problem to be solved

[0008] The solid tire tread rubber in the prior art has a significant problem of insufficient tear resistance when used under high load and harsh environment, and is prone to tearing and cracking, resulting in premature failure of the tire. This not only increases the cost of use, but also brings potential safety hazards. The following are specific deficiencies that need to be urgently solved in the prior art: Insufficient tear resistance: The traditional solid tire tread rubber has poor tear resistance under high load and harsh conditions, and cannot effectively cope with external stress, affecting the service life of the tire. Limitations of reinforcing fillers and blending technology: The existing reinforcing filler and rubber blending technology has limited effect on improving tear resistance and is difficult to meet the high performance requirements in practical applications. Difficulties in the application of new nanomaterials: Although new nanomaterials such as graphene and carbon nanotubes have potential, they have poor dispersibility in rubber and are prone to agglomeration, resulting in unstable performance improvement; at the same time, their high production cost limits industrial application. Insufficient optimization of the vulcanization system: Although the improvement of the existing vulcanization system can improve the performance of the rubber to a certain extent, the breakthrough improvement effect on tear resistance is limited, and the optimization process is often accompanied by an increase in process complexity, which is not conducive to large-scale production.

[0009] Therefore, it is urgent to develop a solid tire tread rubber material with high tear resistance to overcome the above-mentioned deficiencies in the prior art. Specific goals include: improving the tear resistance of the rubber material to adapt to the use requirements of high loads and harsh environments; improving the dispersibility of reinforcing fillers in rubber and reducing production costs; optimizing the vulcanization system to ensure that the rubber material has good processing performance and comprehensive mechanical properties while improving the tear resistance. By solving these problems, the present invention aims to significantly improve the durability and safety of solid tires and meet the high standards required in practical applications.

[0010] Technical Solution

[0011] To solve the above problems, the present invention adopts the following technical solutions.

[0012] A solid tire tread rubber material with high tear resistance, the components are as follows, by weight: rubber matrix: 100-140 parts, carbon black N330 (CAS No.: 1333-86-4): 10-20 parts, white carbon black (CAS No.: 10279-57-9): 10-20 parts, silane coupling agent 2-4 parts, modification auxiliary agent: 5-10 parts, antioxidant 1-2 parts, sulfur 1.5-2.5 parts, zinc oxide: 3-5 parts, stearic acid: 1-2 parts; wherein the preparation method of the modification auxiliary agent is as follows: carbon nanotubes (CAS No.: 308068-56-6) are mixed with ammonium chloride and sulfuric acid. Magnesium was ground in a mortar at a mass ratio of 9:(1-4):(2-4) for 30-60 min, anhydrous ethanol in an amount of 10-20 times the mass of the carbon nanotubes was added for ultrasonic dispersion for 1-4 h, and then N-methylacetamide (CAS No.: 79-16-3) in an amount of 6-12 times the mass of the carbon nanotubes was added, and the mixture was transferred to a tubular furnace and gradually heated under nitrogen protection: 200°C for 0.5 h, 400°C for 1 h, and 600°C for 2 h, and then cooled to room temperature at a cooling rate of 5°C / min, and finally washed with 5% by mass dilute hydrochloric acid to remove metal impurities, and vacuum freeze-dried to obtain a modified auxiliary agent.

[0013] The solid tire tread rubber material with high tear resistance has the following components in parts by weight: rubber matrix: 110-130 parts, carbon black N330: 12-18 parts, white carbon black: 14-20 parts, silane coupling agent: 2-4 parts, modification aid: 5-10 parts, antioxidant: 1-2 parts, sulfur: 1.5-2.5 parts, zinc oxide: 3-5 parts, stearic acid: 1-2 parts; wherein the modification aid is prepared by the following method: carbon nanotubes, ammonium chloride and magnesium sulfate are mixed in a mass ratio of 9: (1-4): (2-4) The mixture was ground in a mortar for 40-60 min, anhydrous ethanol (13-20 times the mass of the carbon nanotubes) was added for ultrasonic dispersion for 1-4 h, and then N-methylacetamide (6-10 times the mass of the carbon nanotubes) was added, and the mixture was transferred to a tubular furnace for gradient heating under nitrogen protection: 200°C for 0.5 h, 400°C for 1 h, and 600°C for 2 h, and then cooled to room temperature at a cooling rate of 5°C / min. Finally, 5% by mass dilute hydrochloric acid was used for washing to remove metal impurities, and vacuum freeze-dried to obtain a modified auxiliary agent.

[0014] The solid tire tread rubber material with high tear resistance has the following components in parts by weight: rubber matrix: 120 parts, carbon black N330: 15 parts, white carbon black: 17 parts, silane coupling agent: 3 parts, modification aid: 8 parts, antioxidant: 2 parts, sulfur: 2 parts, zinc oxide: 4 parts, stearic acid: 2 parts; wherein the preparation method of the modification aid is as follows: grinding carbon nanotubes, ammonium chloride and magnesium sulfate in a mortar at a mass ratio of 9:2:3 for 50 minutes, adding anhydrous ethanol 16 times the mass of the carbon nanotubes for ultrasonic dispersion for 3 hours, then adding N-methylacetamide 8 times the mass of the carbon nanotubes, transferring to a tubular furnace under nitrogen protection, gradient heating: 200°C for 0.5 hours, 400°C for 1 hour, 600°C for 2 hours, then cooling to room temperature, the cooling rate is 5°C / min, finally washing with 5% by mass dilute hydrochloric acid to remove metal impurities, vacuum freeze drying, and obtaining the modification aid.

[0015] The solid tire tread rubber material with high tear resistance, the rubber matrix is ​​natural rubber (CAS No.: 9006-04-6), styrene butadiene rubber (CAS No.: 9003-55-8) or butadiene rubber (CAS No.: 9003-17-2).

[0016] The solid tire tread rubber material with high tear resistance, the silane coupling agent is (3-mercaptopropyl)trimethoxysilane (CAS No.: 4420-74-0), bis-[3-(triethoxysilyl)propyl]tetrasulfide (CAS No.: 40372-72-3), γ-glycidyloxypropyltrimethoxysilane (CAS No.: 2530-83-8) or γ-aminopropyltriethoxysilane (CAS No.: 919-30-2).

[0017] The solid tire tread rubber material with high tear resistance, the antioxidant is 2,2,4-trimethyl-1,2-dihydroquinoline polymer (CAS No.: 26780-96-1) or N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (CAS No.: 793-24-8), and the stearic acid is stearic acid 1801 (high purity (≥99%), acid value 208-212 mgKOH / g, iodine value ≤1.0gI 2 / 100g), stearic acid 1838 (medium carbon chain distribution, acid value 203-212mgKOH / g, suitable for high temperature mixing process) or stearic acid 1860 (containing trace fatty acid regulator, acid value 195-205mgKOH / g, improving processing fluidity).

[0018] The method for preparing a solid tire tread rubber material with high tear resistance as described above comprises the following steps: (1) a raw material pretreatment stage: premixing white carbon black and a silane coupling agent in a high-speed mixer to obtain activated white carbon black; (2) a primary mixing process stage: placing a rubber matrix into an internal mixer, mixing at 75-85° C. for 3-5 minutes, adding activated white carbon black, carbon black N330, and zinc oxide in sequence for mixing, and heating the mixing temperature to 130-150° C. ℃, the mixing time is 8-12min; (3) interface modification stage: adding modification aids for mixing; (4) vulcanization modification stage: cooling to 90-100℃, adding antioxidant, sulfur and stearic acid for mixing, the mixing time is 3-5min, and the temperature of the rubber discharge is 110-120℃; (5) vulcanization molding process: placing the rubber obtained in step (4) into the mold for vulcanization, and water cooling after vulcanization, with a cooling rate of 15℃ / min.

[0019] In the method for preparing a solid tire tread rubber material with high tear resistance, the mixing method in step (3) is to add the modified additive in three steps: first, 30% by weight of the modified additive is added at a temperature of 125° C. for 2 min; then, 50% by weight of the modified additive is added at a temperature of 135° C. for 3 min; and finally, 20% by weight of the modified additive is added at a temperature of 140° C. for 1 min.

[0020] In the method for preparing a solid tire tread rubber material with high tear resistance, the vulcanization method in step (5) is a two-stage vulcanization: the first stage vulcanization is performed at 160° C. under a pressure of 15 MPa for 8 min; the second stage vulcanization is performed at 150° C. under normal pressure for 10 min.

[0021] Beneficial Effects

[0022] Significantly improved tear resistance: By introducing carbon nanotube composite modification additives and combining mechanical chemical grinding and gradient pyrolysis processes to prepare a three-dimensional reinforced network structure, the present invention increases the tear strength of the rubber by more than 40%, reaching 60-65kN / m. This improvement effectively solves the problem of solid tires being prone to tearing and cracking under high loads and harsh environments, and significantly extends the service life of the tires. Compared with traditional reinforcing fillers (such as carbon black and white carbon black) or rubber blending technology, the present invention has achieved a breakthrough in tear resistance and is particularly suitable for high-demand scenarios such as industrial vehicles and port machinery.

[0023] Excellent wear resistance and durability: The Akron wear loss of the rubber compound is reduced by 28% to 0.14-0.16cm³, showing excellent wear resistance, which helps to reduce tire wear during use and extend the replacement cycle. At the same time, the fatigue life is increased to 900,000-1,000,000 times, far exceeding the 500,000-600,000 times of traditional rubber compounds, ensuring that the tire can maintain stable performance under long-term and high-frequency use, thereby reducing maintenance costs and equipment downtime.

[0024] Reduce dynamic heat generation and improve safety: The present invention reduces the dynamic heat generation of the rubber by 35%, and controls the temperature rise to 14-16°C, significantly reducing the performance degradation and safety hazards caused by heat accumulation when the tire is running at high speed or under heavy load. This feature not only improves the durability of the tire, but also enhances the safety of equipment operation, especially when used in high temperature environments, it can effectively reduce the risk of tire blowout or tire failure.

[0025] Maintain good comprehensive mechanical properties: the tensile strength of the rubber reaches 24-26MPa, the elongation at break is 470-490%, and the Shore A hardness is maintained at 65±3, achieving a balance between high strength and high toughness. In addition, the rebound performance is increased to 58-61%, reducing energy loss, improving the rolling efficiency of the tire, and thus reducing energy consumption.

[0026] Overcoming the application difficulties of new nanomaterials: In view of the poor dispersion and easy agglomeration of new nanomaterials (such as carbon nanotubes and graphene) in rubber, the present invention achieves uniform dispersion and efficient enhancement of carbon nanotubes through a unique modification additive preparation process and three-step gradient mixing technology. Compared with the existing technology that directly uses unmodified nanomaterials, the present invention significantly improves material utilization efficiency, reduces production costs, and avoids performance instability caused by agglomeration.

[0027] Process feasibility and cost advantage: The preparation process of the present invention adopts conventional equipment (such as internal mixer, tubular furnace), with clear process flow, simple operation, and easy to realize industrial production. Although the preparation of modified additives involves multiple steps, the cost of raw materials (such as carbon nanotubes, ammonium chloride, magnesium sulfate) is controllable, and the amount of additives used is only 5-10 parts, with obvious overall cost advantages. Compared with the existing technology using highly dispersed silica or new nanomaterials, the present invention maintains a low production cost while improving performance, and has good economic benefits.

[0028] Broad application prospects: The rubber compound is suitable for the manufacture of solid tires in the fields of industrial vehicles, port machinery, engineering machinery, etc., and can significantly improve the durability and safety of tires under high load and harsh environments. By extending the service life of tires and reducing maintenance frequency, the present invention reduces equipment operating costs and improves production efficiency, which is of great significance to promoting technological progress and industrial development in related industries.

[0029] In summary, the present invention has developed a solid tire tread rubber material with high tear resistance through innovative carbon nanotube composite modification additives, three-step gradient mixing technology and two-stage vulcanization process. Its significant improvement in tear strength, wear resistance, durability and safety overcomes the shortcomings of the existing technology, and with its process feasibility and cost advantages, it provides a new technical path for upgrading the performance of solid tires, and has broad prospects for industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a scanning electron microscope image of the rubber material prepared in Example 5, in which the smallest interval of the scale is 2.00 um.

[0031] Figure 2 This is a physical picture of the modified auxiliary agent prepared in Example 5. DETAILED DESCRIPTION

[0032] The present invention is further described below in conjunction with specific embodiments.

[0033] Unless otherwise defined, the technical and scientific terms used in the following examples have the same meanings as commonly understood by those skilled in the art to which the present invention belongs. In practical application, the weight parts referred to in the present invention can be set as the unit kilogram.

[0034] Example 1

[0035] A solid tire tread rubber material with high tear resistance has the following components, in parts by weight: rubber matrix: 100 parts, carbon black N330: 10 parts, white carbon black: 10 parts, silane coupling agent: 2 parts, modification aid: 5 parts, antioxidant: 1 part, sulfur: 1.5 parts, zinc oxide: 3 parts, stearic acid: 1 part; wherein the preparation method of the modification aid is as follows: grinding carbon nanotubes, ammonium chloride and magnesium sulfate in a mortar at a mass ratio of 9:1:2 for 30 minutes, adding anhydrous ethanol 10 times the mass of the carbon nanotubes for ultrasonic dispersion for 1 hour, then adding N-methylacetamide 6 times the mass of the carbon nanotubes, transferring to a tubular furnace under nitrogen protection, gradient heating: 200°C for 0.5h, 400°C for 1h, 600°C for 2h, then cooling to room temperature, the cooling rate is 5°C / min, finally washing with 5% by mass dilute hydrochloric acid to remove metal impurities, vacuum freeze drying, and obtaining the modification aid. The rubber matrix is ​​natural rubber, the silane coupling agent is (3-mercaptopropyl) trimethoxysilane, the antioxidant is 2,2,4-trimethyl-1,2-dihydroquinoline polymer, and the stearic acid is stearic acid 1801.

[0036] For example, a method for preparing a solid tire tread rubber compound with high tear resistance comprises the following steps: (1) raw material pretreatment stage: premixing white carbon black and a silane coupling agent in a high-speed mixer to obtain activated white carbon black; (2) primary mixing process stage: placing a rubber matrix into an internal mixer, mixing at 75°C for 3 minutes, adding activated white carbon black, carbon black N330, and zinc oxide in sequence for mixing, and raising the mixing temperature to 130°C for 8 minutes; (3) interface modification stage: adding a modification aid for mixing; (4) vulcanization modification stage: cooling to 90°C, adding an antioxidant, sulfur, and stearic acid for mixing, and mixing for 3 minutes, while the temperature for rubber removal is 110°C; (5) vulcanization molding process: placing the rubber compound obtained in step (4) into a mold for vulcanization, and water cooling after vulcanization, with a cooling rate of 15°C / min. The mixing method in step (3) is to add the modified additive in three steps: first, 30% by weight of the modified additive is added at a temperature of 125°C for 2 minutes; then, 50% by weight of the modified additive is added at a temperature of 135°C for 3 minutes; finally, 20% by weight of the modified additive is added at a temperature of 140°C for 1 minute. The vulcanization method in step (5) is two-stage vulcanization: the first stage vulcanization is performed at 160°C for 8 minutes at a pressure of 15 MPa; the second stage vulcanization is performed at 150°C for 10 minutes at normal pressure.

[0037] Example 2

[0038] The solid tire tread rubber material with high tear resistance has the following components in parts by weight: rubber matrix: 140 parts, carbon black N330: 20 parts, white carbon black: 20 parts, silane coupling agent: 4 parts, modification aid: 10 parts, antioxidant: 2 parts, sulfur: 2.5 parts, zinc oxide: 5 parts, stearic acid: 2 parts; wherein the preparation method of the modification aid is as follows: grinding carbon nanotubes, ammonium chloride and magnesium sulfate in a mortar at a mass ratio of 9:4:4 for 60 minutes, adding anhydrous ethanol 20 times the mass of the carbon nanotubes for ultrasonic dispersion for 4 hours, then adding N-methylacetamide 12 times the mass of the carbon nanotubes, transferring to a tubular furnace under nitrogen protection, gradient heating: 200°C for 0.5 hours, 400°C for 1 hour, 600°C for 2 hours, then cooling to room temperature, the cooling rate is 5°C / min, finally washing with 5% by mass dilute hydrochloric acid to remove metal impurities, vacuum freeze drying, and obtaining the modification aid. The rubber matrix is ​​styrene-butadiene rubber, the silane coupling agent is bis-[3-(triethoxysilyl)propyl]tetrasulfide, the antioxidant is N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, and the stearic acid is stearic acid 1838.

[0039] For example, a method for preparing a solid tire tread rubber compound with high tear resistance comprises the following steps: (1) raw material pretreatment stage: premixing white carbon black and a silane coupling agent in a high-speed mixer to obtain activated white carbon black; (2) primary mixing process stage: placing a rubber matrix into an internal mixer, mixing at 85°C for 5 minutes, adding activated white carbon black, carbon black N330, and zinc oxide in sequence for mixing, and raising the mixing temperature to 150°C for 12 minutes; (3) interface modification stage: adding a modification aid for mixing; (4) vulcanization modification stage: cooling to 100°C, adding an antioxidant, sulfur, and stearic acid for mixing, and mixing for 5 minutes, while the temperature for rubber removal is 120°C; (5) vulcanization molding process: placing the rubber compound obtained in step (4) into a mold for vulcanization, and water cooling after vulcanization, with a cooling rate of 15°C / min. The mixing method in step (3) is to add the modified additive in three steps: first, 30% by weight of the modified additive is added at a temperature of 125°C for 2 minutes; then, 50% by weight of the modified additive is added at a temperature of 135°C for 3 minutes; finally, 20% by weight of the modified additive is added at a temperature of 140°C for 1 minute. The vulcanization method in step (5) is two-stage vulcanization: the first stage vulcanization is performed at 160°C for 8 minutes at a pressure of 15 MPa; the second stage vulcanization is performed at 150°C for 10 minutes at normal pressure.

[0040] Example 3

[0041] A solid tire tread rubber material with high tear resistance has the following components, in parts by weight: rubber matrix: 110 parts, carbon black N330: 12 parts, white carbon black: 14 parts, silane coupling agent: 2 parts, modification aid: 5 parts, antioxidant: 1 part, sulfur: 1.5 parts, zinc oxide: 3 parts, stearic acid: 1 part; wherein the preparation method of the modification aid is as follows: grinding carbon nanotubes, ammonium chloride and magnesium sulfate in a mortar at a mass ratio of 9:1:2 for 40 minutes, adding anhydrous ethanol 13 times the mass of the carbon nanotubes for ultrasonic dispersion for 1 hour, then adding N-methylacetamide 6 times the mass of the carbon nanotubes, transferring to a tubular furnace under nitrogen protection, gradient heating: 200°C for 0.5h, 400°C for 1h, 600°C for 2h, then cooling to room temperature, the cooling rate is 5°C / min, finally washing with 5% by mass dilute hydrochloric acid to remove metal impurities, vacuum freeze drying, and obtaining the modification aid. The rubber matrix is ​​butadiene rubber, the silane coupling agent is γ-glycidyloxypropyltrimethoxysilane, the antioxidant is 2,2,4-trimethyl-1,2-dihydroquinoline polymer, and the stearic acid is stearic acid 1860.

[0042] For example, a method for preparing a solid tire tread rubber compound with high tear resistance comprises the following steps: (1) raw material pretreatment stage: premixing white carbon black and a silane coupling agent in a high-speed mixer to obtain activated white carbon black; (2) primary mixing process stage: placing a rubber matrix into an internal mixer, mixing at 78°C for 3 minutes, adding activated white carbon black, carbon black N330, and zinc oxide in sequence for mixing, and heating the mixing temperature to 135°C for 9 minutes; (3) interface modification stage: adding a modification aid for mixing; (4) vulcanization modification stage: cooling the temperature to 93°C, adding an antioxidant, sulfur, and stearic acid for mixing, and mixing for 3 minutes, while the temperature of the rubber discharge is 113°C; (5) vulcanization molding process: placing the rubber compound obtained in step (4) into a mold for vulcanization, and water cooling after vulcanization, with a cooling rate of 15°C / min. The mixing method in step (3) is to add the modified additive in three steps: first, 30% by weight of the modified additive is added at a temperature of 125°C for 2 minutes; then, 50% by weight of the modified additive is added at a temperature of 135°C for 3 minutes; finally, 20% by weight of the modified additive is added at a temperature of 140°C for 1 minute. The vulcanization method in step (5) is two-stage vulcanization: the first stage vulcanization is performed at 160°C for 8 minutes at a pressure of 15 MPa; the second stage vulcanization is performed at 150°C for 10 minutes at normal pressure.

[0043] Example 4

[0044] The solid tire tread rubber material with high tear resistance has the following components in parts by weight: rubber matrix: 125 parts, carbon black N330: 17 parts, white carbon black: 18 parts, silane coupling agent: 4 parts, modification aid: 9 parts, antioxidant: 2 parts, sulfur: 2.2 parts, zinc oxide: 5 parts, stearic acid: 2 parts; wherein the preparation method of the modification aid is as follows: grinding carbon nanotubes, ammonium chloride and magnesium sulfate in a mortar at a mass ratio of 9:3:4 for 55 minutes, adding anhydrous ethanol 18 times the mass of the carbon nanotubes for ultrasonic dispersion for 4 hours, then adding N-methylacetamide 9 times the mass of the carbon nanotubes, transferring to a tubular furnace under nitrogen protection, gradient heating: 200°C for 0.5 hours, 400°C for 1 hour, 600°C for 2 hours, then cooling to room temperature, the cooling rate is 5°C / min, finally washing with 5% by mass dilute hydrochloric acid to remove metal impurities, vacuum freeze drying, and obtaining the modification aid. The rubber matrix is ​​natural rubber, the silane coupling agent is γ-aminopropyltriethoxysilane, the antioxidant is N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, and the stearic acid is stearic acid 1801.

[0045] For example, a method for preparing a solid tire tread rubber compound with high tear resistance comprises the following steps: (1) raw material pretreatment stage: premixing white carbon black and a silane coupling agent in a high-speed mixer to obtain activated white carbon black; (2) primary mixing process stage: placing a rubber matrix into an internal mixer, mixing at 84°C for 5 minutes, adding activated white carbon black, carbon black N330, and zinc oxide in sequence for mixing, and raising the mixing temperature to 145°C for 11 minutes; (3) interface modification stage: adding a modification aid for mixing; (4) vulcanization modification stage: cooling to 98°C, adding an antioxidant, sulfur, and stearic acid for mixing, and mixing for 5 minutes, while the temperature for rubber removal is 118°C; (5) vulcanization molding process: placing the rubber compound obtained in step (4) into a mold for vulcanization, and water cooling after vulcanization, with a cooling rate of 15°C / min. The mixing method in step (3) is to add the modified additive in three steps: first, 30% by weight of the modified additive is added at a temperature of 125°C for 2 minutes; then, 50% by weight of the modified additive is added at a temperature of 135°C for 3 minutes; finally, 20% by weight of the modified additive is added at a temperature of 140°C for 1 minute. The vulcanization method in step (5) is two-stage vulcanization: the first stage vulcanization is performed at 160°C for 8 minutes at a pressure of 15 MPa; the second stage vulcanization is performed at 150°C for 10 minutes at normal pressure.

[0046] Example 5

[0047] The solid tire tread rubber material with high tear resistance has the following components in parts by weight: rubber matrix: 120 parts, carbon black N330: 15 parts, white carbon black: 17 parts, silane coupling agent: 3 parts, modification aid: 8 parts, antioxidant: 2 parts, sulfur: 2 parts, zinc oxide: 4 parts, stearic acid: 2 parts; wherein the preparation method of the modification aid is as follows: grinding carbon nanotubes, ammonium chloride and magnesium sulfate in a mortar at a mass ratio of 9:2:3 for 50 minutes, adding anhydrous ethanol 16 times the mass of the carbon nanotubes for ultrasonic dispersion for 3 hours, then adding N-methylacetamide 8 times the mass of the carbon nanotubes, transferring to a tubular furnace under nitrogen protection, gradient heating: 200°C for 0.5 hours, 400°C for 1 hour, 600°C for 2 hours, then cooling to room temperature, the cooling rate is 5°C / min, finally washing with 5% by mass dilute hydrochloric acid to remove metal impurities, vacuum freeze drying, and obtaining the modification aid. The rubber matrix is ​​styrene-butadiene rubber, the silane coupling agent is (3-mercaptopropyl)trimethoxysilane, the antioxidant is 2,2,4-trimethyl-1,2-dihydroquinoline polymer, and the stearic acid is stearic acid 1838.

[0048] For example, a method for preparing a solid tire tread rubber compound with high tear resistance comprises the following steps: (1) raw material pretreatment stage: premixing white carbon black and a silane coupling agent in a high-speed mixer to obtain activated white carbon black; (2) primary mixing process stage: placing a rubber matrix into an internal mixer, mixing at 80°C for 4 minutes, adding activated white carbon black, carbon black N330, and zinc oxide in sequence for mixing, and heating the mixing temperature to 140°C for 10 minutes; (3) interface modification stage: adding a modification aid for mixing; (4) vulcanization modification stage: cooling the temperature to 95°C, adding an antioxidant, sulfur, and stearic acid for mixing, and mixing for 4 minutes, while the temperature of the rubber discharge is 115°C; (5) vulcanization molding process: placing the rubber compound obtained in step (4) into a mold for vulcanization, and water cooling after vulcanization, with a cooling rate of 15°C / min. The mixing method in step (3) is to add the modified additive in three steps: first, 30% by weight of the modified additive is added at a temperature of 125°C for 2 minutes; then, 50% by weight of the modified additive is added at a temperature of 135°C for 3 minutes; finally, 20% by weight of the modified additive is added at a temperature of 140°C for 1 minute. The vulcanization method in step (5) is two-stage vulcanization: the first stage vulcanization is performed at 160°C for 8 minutes at a pressure of 15 MPa; the second stage vulcanization is performed at 150°C for 10 minutes at normal pressure.

[0049] Comparative Example 1

[0050] Same as Example 5, but without adding the modifying aid.

[0051] Comparative Example 2

[0052] Same as Example 5, the modification aid is directly replaced by untreated carbon nanotubes.

[0053] Comparative Example 3

[0054] The same as Example 5, except that the mass ratio of carbon nanotubes / ammonium chloride / magnesium sulfate was changed to 4:0.5:1.

[0055] Comparative Example 4

[0056] Similar to Example 5, the interface modification stage was changed to adding all the modification aids at one time (gradient addition was cancelled), the mixing temperature was uniformly set at 135° C., and the mixing time was 6 min.

[0057] Comparative Example 5

[0058] Same as Example 5, the vulcanization method was changed to single-stage vulcanization (160°C / 15MPa, 18min).

[0059] Comparative Example 6

[0060] As in Example 5, white carbon black and silane coupling agent were removed.

[0061] Test plan

[0062] (1) Physical and mechanical properties test: Tear strength: ASTM D624 standard, dumbbell-shaped specimen, test speed 500 mm / min; Tensile strength and elongation at break: GB / T528, tensile rate 500 mm / min; Hardness: Shore A durometer (GB / T531.1).

[0063] (2) Dynamic performance test: Dynamic heat generation: using Goodrich flexure tester, test conditions 70℃ / 3.5MPa / 25Hz, record the temperature rise; rebound performance: DIN53512 standard, drop hammer height 50mm.

[0064] (3) Wear resistance and durability: Akron wear test: GB / T1689, load 26.7N, grinding wheel speed 76rpm; fatigue life: MTS dynamic fatigue testing machine, strain amplitude 50%, frequency 5Hz.

[0065] Table 1 Test results (Examples 1-5, Comparative Examples 1-6)

[0066]

[0067] Combined with Table 1, the following is an in-depth analysis of the mechanism of improving the performance of the rubber compound from three aspects: modification additives, interface optimization and process innovation, and the importance of key factors is explained in combination with comparative examples. The role of modification additives: Mechanism: The modification additives compound carbon nanotubes with ammonium chloride and magnesium sulfate through mechanical chemical grinding and gradient pyrolysis processes to form a three-dimensional reinforced network structure. This structure effectively disperses stress and improves the tear strength (60-65kN / m), tensile strength (24-26MPa) and elongation at break (470-490%) of the rubber compound. At the same time, the three-dimensional network reduces internal friction, reduces dynamic heat generation (14-16℃) and Akron wear (0.14-0.16cm³), and improves rebound (58-61%) and fatigue life (900,000-1 million times). Comparative example verification: Comparative example 1 (no modification additive): The performance is the worst (such as tear strength of only 35kN / m), indicating that the modification additive is the key to performance improvement. Comparative Example 2 (unmodified carbon nanotubes): poor performance, proving the necessity of the modification process to form an effective reinforcement network. Comparative Example 3 (changing the mass ratio of carbon nanotubes / ammonium chloride / magnesium sulfate): performance decreased, indicating that the optimization of the formula ratio is crucial. The role of interface optimization: Mechanism: Silane coupling agent and white carbon black work synergistically to enhance the interfacial bonding between the filler and the rubber matrix. This optimization improves the hardness (66-69ShoreA), tensile strength and elongation at break of the rubber compound, while reducing the sliding friction between the filler and the matrix, and reducing dynamic heat generation and Akron wear. Comparative example verification: Comparative Example 6 (removing white carbon black and silane coupling agent): the performance is the worst (such as hardness drops to 58ShoreA, wear increases to 0.30cm³), proving the irreplaceable role of white carbon black and silane coupling agent for interface optimization. The role of process innovation: Mechanism: Three-step gradient mixing technology: ensures the uniform dispersion of the modified additives in the rubber compound, avoids agglomeration, and improves the comprehensive performance of the rubber compound. Two-stage vulcanization process: optimizes the cross-linked network structure, so that the rubber achieves a balance between high strength (tear strength, tensile strength) and high toughness (elongation at break), while reducing dynamic heat generation. Comparative example verification: Comparative example 4 (gradient mixing is cancelled): performance decreases (such as rebound drops to 48-58%), indicating the significant effect of uniform dispersion on performance. Comparative example 5 (single-stage vulcanization): performance deteriorates (such as fatigue life drops to 400,000-800,000 times), proving the importance of two-stage vulcanization process for cross-linked network optimization. Comprehensive mechanism summary: Modified additives improve the mechanical properties and fatigue resistance of the rubber through a three-dimensional reinforced network. Interface optimization enhances the bonding force between the filler and the matrix, and improves hardness and wear resistance. Process innovation ensures the overall improvement of the comprehensive performance of the rubber by uniformly dispersing and optimizing the cross-linked network. The excellent performance of Examples 1-5 is due to the synergistic effect of modified additives, interface optimization and process innovation, while the performance defects of Comparative Examples 1-6 reflect that the lack of any key factor will significantly reduce the quality of the rubber.This analysis reveals the core mechanism of the design of high tear resistance solid tire tread rubber. In addition, taking Example 5 as an example, the scanning electron microscope image of its cross section is as follows. Figure 1 As shown, it can be seen that the surface is evenly distributed and smooth. At the same time, the prepared modified additive, its actual picture is as follows Figure 2 shown.

[0068] The above contents are further detailed descriptions of the present invention in combination with specific implementation methods. It cannot be considered that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the field of modified rubber technology to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as belonging to the protection scope determined by the claims submitted by the present invention.

Claims

1. A solid tire tread rubber material with high tear resistance, characterized in that: The components are as follows, in parts by weight: rubber matrix: 100-140 parts, carbon black N330: 10-20 parts, white carbon black: 10-20 parts, silane coupling agent: 2-4 parts, modification aid: 5-10 parts, antioxidant: 1-2 parts, sulfur: 1.5-2.5 parts, zinc oxide: 3-5 parts, stearic acid: 1-2 parts; wherein the preparation method of the modification aid is as follows: grind carbon nanotubes, ammonium chloride and magnesium sulfate in a mortar at a mass ratio of 9: (1-4): (2-4) for 30- The mixture was heated to 200 °C for 60 min, anhydrous ethanol (10-20 times the mass of the carbon nanotubes) was added for ultrasonic dispersion for 1-4 h, and then N-methylacetamide (6-12 times the mass of the carbon nanotubes) was added, and the mixture was transferred to a tubular furnace for gradient heating under nitrogen protection: 200 °C for 0.5 h, 400 °C for 1 h, and 600 °C for 2 h, and then cooled to room temperature at a cooling rate of 5 °C / min. Finally, 5% by mass dilute hydrochloric acid was used for washing to remove metal impurities, and the mixture was freeze-dried in vacuum to obtain a modified auxiliary agent.

2. The solid tire tread rubber material with high tear resistance according to claim 1, characterized in that: The components are as follows in parts by weight: rubber matrix: 110-130 parts, carbon black N330: 12-18 parts, white carbon black: 14-20 parts, silane coupling agent: 2-4 parts, modification aid: 5-10 parts, antioxidant: 1-2 parts, sulfur: 1.5-2.5 parts, zinc oxide: 3-5 parts, stearic acid: 1-2 parts; wherein the preparation method of the modification aid is as follows: grind carbon nanotubes, ammonium chloride and magnesium sulfate in a mortar at a mass ratio of 9: (1-4): (2-4) for 40- The mixture was heated to 200 °C for 60 min, anhydrous ethanol (13-20 times the mass of the carbon nanotubes) was added for ultrasonic dispersion for 1-4 h, and then N-methylacetamide (6-10 times the mass of the carbon nanotubes) was added, and the mixture was transferred to a tubular furnace for gradient heating under nitrogen protection: 200 °C for 0.5 h, 400 °C for 1 h, and 600 °C for 2 h, and then cooled to room temperature at a cooling rate of 5 °C / min. Finally, 5% by mass dilute hydrochloric acid was used for washing to remove metal impurities, and the mixture was freeze-dried in vacuum to obtain a modified auxiliary agent.

3. The solid tire tread rubber material with high tear resistance according to claim 2, characterized in that: The components are as follows in parts by weight: rubber matrix: 120 parts, carbon black N330: 15 parts, white carbon black: 17 parts, silane coupling agent: 3 parts, modification agent: 8 parts, antioxidant: 2 parts, sulfur: 2 parts, zinc oxide: 4 parts, stearic acid: 2 parts; wherein the preparation method of the modification agent is as follows: grind carbon nanotubes, ammonium chloride and magnesium sulfate in a mortar at a mass ratio of 9:2:3 for 50 minutes, add anhydrous ethanol 16 times the mass of the carbon nanotubes for ultrasonic dispersion for 3 hours, then add N-methylacetamide 8 times the mass of the carbon nanotubes, transfer to a tubular furnace under nitrogen protection, and gradually increase the temperature: 200°C for 0.5h, 400°C for 1h, 600°C for 2h, then cool to room temperature, the cooling rate is 5°C / min, and finally use 5% by mass dilute hydrochloric acid to wash and remove metal impurities, and vacuum freeze-dry to obtain the modification agent.

4. The solid tire tread rubber material with high tear resistance according to claim 1, characterized in that: The rubber matrix is ​​natural rubber, styrene-butadiene rubber or butadiene rubber.

5. The solid tire tread rubber material with high tear resistance according to claim 1, characterized in that: The silane coupling agent is (3-mercaptopropyl)trimethoxysilane, bis-[3-(triethoxysilyl)propyl]tetrasulfide, γ-glycidyloxypropyltrimethoxysilane or γ-aminopropyltriethoxysilane.

6. The solid tire tread rubber material with high tear resistance according to claim 1, characterized in that: The antioxidant is 2,2,4-trimethyl-1,2-dihydroquinoline polymer or N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, and the stearic acid is stearic acid 1801, stearic acid 1838 or stearic acid 1860.

7. The method for preparing a solid tire tread rubber material with high tear resistance as claimed in claim 1, characterized in that: The following steps are involved: (1) Raw material pretreatment stage: premix silica and silane coupling agent in a high-speed mixer to obtain activated silica; (2) Primary mixing process stage: put the rubber matrix into an internal mixer, mix at 75-85°C for 3-5 minutes, add activated silica, carbon black N330 and zinc oxide in turn for mixing, the mixing temperature is raised to 130-150°C, and the mixing time is 8-12 minutes; (3) Interface modification stage: add modification additives for mixing; (4) Vulcanization modification stage: cool to 90-100°C, add antioxidant, sulfur and stearic acid for mixing, the mixing time is 3-5 minutes, and the temperature of rubber removal is 110-120°C; (5) Vulcanization molding process: put the rubber obtained in step (4) into a mold for vulcanization, and water cool after vulcanization, with a cooling rate of 15°C / min.

8. The method for preparing a solid tire tread rubber material with high tear resistance according to claim 7, characterized in that: The mixing method in step (3) is to add the modified additive in three steps: first, 30% by weight of the modified additive is added at a temperature of 125° C. for 2 min; then, 50% by weight of the modified additive is added at a temperature of 135° C. for 3 min; and finally, 20% by weight of the modified additive is added at a temperature of 140° C. for 1 min.

9. The method for preparing a solid tire tread rubber material with high tear resistance according to claim 8, characterized in that: The vulcanization in step (5) is performed in two stages: the first stage is vulcanization at 160° C. for 8 min under a pressure of 15 MPa; The second stage of vulcanization is carried out at 150°C for 10 minutes under normal pressure.

Images