Bus tire tread rubber composition, bus tire tread rubber and preparation method thereof

Abstract

The invention provides a bus tire tread rubber composition, a bus tire tread rubber and a preparation method thereof, and relates to the technical field of tire manufacturing. The bus tire tread rubber composition comprises the following components in parts by weight: 100 parts of raw rubber; 45 to 60 parts of a modified carbon nanotube / carbon black aggregate; 1-12 parts of an active agent; 0.8 to 6 parts of an accelerant; 0.8-6 parts of a vulcanizing agent; 1-5 parts of an anti-aging agent; 0.5 to 2.5 parts of protective wax; 0-0.3 part of a scorch retarder; and 0-6 parts of a processing aid. Wherein the modified carbon nanotube / carbon black aggregate is obtained by carrying out high-temperature jet flow on a modifier and a carbon nanotube / carbon black aggregate. The modified carbon nanotube / carbon black aggregate is added into the bus tire tread rubber composition, so that the mechanical property of the bus tire tread rubber composition is remarkably enhanced, heat generation is reduced, and abrasion is improved.

Description

Technical Field

[0001] The invention relates to the technical field of tire manufacturing, and in particular to a bus tire tread rubber material composition, a bus tire tread rubber material and a preparation method thereof. Background Art

[0002] The bus tire tread refers to the part of the bus tire that is in direct contact with the road surface, usually located on the outermost layer of the tire. It is an important component of the tire and is mainly responsible for providing friction between the vehicle and the road surface, thereby achieving the vehicle's traction and braking ability. The design and material selection of the tread have a significant impact on the performance of the tire, including wear resistance, grip, rolling resistance and noise. The tread is usually made of wear-resistant rubber material and has a specific pattern design to adapt to different driving conditions and road types.

[0003] Adding carbon black to the tread rubber composition of bus tires can improve the mechanical properties of the tread, enhance the strength and hardness of the tread, improve wear resistance, improve the thermal conductivity of the tread, and enhance grip and handling. However, during the production process, carbon black particles tend to aggregate together, resulting in poor dispersion in the rubber matrix. This will affect the reinforcement effect of carbon black, so that the performance of the tire cannot reach the optimal state. Although carbon black can improve the wear resistance and aging resistance of the tire, its high specific surface area and surface activity will also increase the rolling resistance of the tire. This will lead to reduced fuel economy of the vehicle. When the amount of carbon black added is too high, the hardness of the tire will increase. Although the increase in hardness helps to improve the wear resistance and tear resistance of the tire, it may also reduce the comfort of the tire. Too high an amount of carbon black added will reduce the elasticity and resilience of the tire, thereby affecting the grip of the tire to a certain extent.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The object of the present invention is to provide a bus tire tread rubber composition, a bus tire tread rubber and a preparation method thereof. The bus tire tread rubber composition of the present invention significantly enhances the mechanical properties of the bus tire tread rubber, reduces heat generation and improves wear by adding modified carbon nanotubes / carbon black aggregates.

[0006] In order to solve the above technical problems, the present invention particularly adopts the following technical solutions: In a first aspect, the present invention provides a bus tire tread rubber composition, comprising the following components by weight: 100 parts of raw rubber; 45-60 parts of modified carbon nanotube / carbon black aggregate; 1~12 parts of active agent; Accelerator 0.8~6 parts; Vulcanizing agent 0.8~6 parts; 1~5 parts of antioxidant; 0.5~2.5 parts of protective wax; Anti-scorch agent 0~0.3 parts; Processing aids 0~6 parts; Wherein, the modified carbon nanotube / carbon black aggregate is obtained by high-temperature jetting of a modifier and carbon nanotube / carbon black aggregate; the modifier is selected from at least one of the compounds represented by the following formulas I to V: ; Wherein, n and m are each independently selected from positive integers between 1 and 10; M is selected from alkali metals and / or alkaline earth metals; R 1 and R 2 Each independently selected from or , p is a positive integer between 1 and 5.

[0007] Furthermore, the modifier is selected from at least one of the following compounds: .

[0008] And / or, the carbon nanotube / carbon black aggregates are obtained by powder spraying carbon nanotubes and carbon black primary particles.

[0009] And / or, the content of the carbon nanotubes is 1-10% of the total mass of the carbon nanotube / carbon black aggregate.

[0010] And / or, the grade of the carbon black primary particles is N134.

[0011] And / or, the amount of the modifier is 0.8-4% by weight of the carbon black.

[0012] Furthermore, the modified carbon nanotube / carbon black aggregate is prepared by the following steps: (a) Through powder injection, a suspension of carbon nanotubes is sprayed into a carbon black reactor, and the carbon nanotubes and carbon black primary particles combine to form a pre-agglomerate; through the aggregation of carbon black, carbon nanotube / carbon black aggregates are formed.

[0013] (b) combining the modifier with the carbon nanotube / carbon black aggregate by high temperature jet to obtain the modified carbon nanotube / carbon black aggregate.

[0014] Furthermore, in step (a), in the carbon nanotube suspension, the mass proportion of carbon nanotubes is 15-40%, and the remainder is water.

[0015] And / or, in step (a), the injection rate of the carbon nanotube suspension is 50-200 kg / h.

[0016] And / or, in step (a), the temperature for combining to form the pre-agglomerate is 800-1000°C.

[0017] And / or, in step (a), the temperature for forming the carbon nanotube / carbon black aggregate is 600-1000°C.

[0018] Furthermore, in step (b), the injection rate of the modifier is 20-100 kg / h.

[0019] And / or, in step (b), the temperature at which the modifier combines with the carbon nanotube / carbon black aggregate is 100-480°C.

[0020] And / or, in step (b), after the modifier is combined with the carbon nanotube / carbon black aggregate, the following post-treatment step is also included: The powder product is obtained through cooling, filtering and collecting and separating; the powder product, a binder and water are mixed, granulated and then dried to obtain the modified carbon nanotube / carbon black aggregate.

[0021] And / or, the mass ratio of the powdered product, the binder and water is (80-100):(0.1-2):(0.01-10).

[0022] And / or, the binder is selected from lignin and / or molasses.

[0023] And / or, the particle size of the modified carbon nanotube / carbon black aggregate is 0.1-2.5 μm.

[0024] Furthermore, the raw rubber includes necessarily natural rubber, and optionally butadiene rubber and / or styrene butadiene rubber.

[0025] And / or, the weight proportion of butadiene rubber and / or styrene butadiene rubber is 20 to 50 parts.

[0026] And / or, the active agent comprises stearic acid and / or zinc oxide.

[0027] And / or, the accelerator comprises accelerator NS.

[0028] And / or, the vulcanizing agent includes sulfur.

[0029] And / or, the antioxidant includes antioxidant 4020 and / or antioxidant RD.

[0030] And / or, the protective wax includes microcrystalline wax.

[0031] And / or, the anti-scorch agent includes anti-scorch agent CTP.

[0032] Furthermore, the processing aid includes DCPD.

[0033] In a second aspect, the present invention provides a bus tire tread rubber material, which is obtained by mixing the bus tire tread rubber material composition.

[0034] In a third aspect, the present invention provides a method for preparing a tread rubber material for a bus tire, comprising: (1) Raw rubber, modified carbon nanotube / carbon black aggregate, active agent, antioxidant, protective wax and processing aid are mixed and kneaded to obtain a masterbatch.

[0035] (2) The primary masterbatch, the vulcanizing agent, the accelerator and the anti-scorching agent are mixed and kneaded in two stages to obtain the bus tire tread rubber material.

[0036] Furthermore, in step (1), the mixing stage includes the following steps: mixing for 20 to 40 seconds, lifting the top pin, holding for 10 to 15 seconds, and pressing the top pin; mixing until the temperature reaches 135 to 145°C, lifting the top pin, holding for 10 to 15 seconds, and pressing the top pin; mixing until the temperature reaches 145 to 155°C for debonding.

[0037] In step (2), the two-stage mixing includes the following steps: after mixing for 10 to 60 seconds, lift the top bolt, hold for 0 to 15 seconds, and press the top bolt; after mixing until the temperature reaches 70 to 85°C, lift the top bolt, hold for 0 to 15 seconds, and press the top bolt; after mixing until the temperature reaches 100 to 120°C, remove the glue.

[0038] Compared with the prior art, the present invention has the following beneficial effects: The bus tire tread rubber composition provided by the present invention has modified carbon nanotube / carbon black aggregates added therein, and the aggregates not only maintain the large aspect ratio of the carbon nanotubes themselves, but also improve the dispersibility, reinforcement and reactivity of the carbon nanotubes and carbon black in the rubber matrix with rubber groups, enhance the interaction between the raw rubber and the filler, and reduce the agglomeration of the filler, thereby further enhancing the mechanical properties of the bus tire tread rubber composition, reducing heat generation, and improving wear resistance. The present invention uses a modifier to first modify the carbon nanotube / carbon black aggregates and then add them to the bus tire tread rubber composition, forming a "physical-chemical" dual reinforcement mechanism. Compared with the two being added to the rubber composition in the form of physical blending at a later stage, the bus tire tread rubber has better dispersibility, stronger mechanical properties, and higher stability. In addition, the first modification of the carbon nanotube / carbon black aggregates also has higher functionalization efficiency from a process perspective, which helps to improve processing performance.

[0039] The bus tire tread rubber material provided by the present invention, in view of the advantages of the above composition, enables the bus tire tread rubber material obtained by mixing to have better mechanical properties and wear resistance, and can further reduce the heat generation of the bus tire tread rubber material.

[0040] The method for preparing the bus tire tread rubber material provided by the invention has continuous process, high mechanization degree and is suitable for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0042] Figure 1 This is a scanning electron microscope image of the modified carbon nanotube / carbon black aggregate prepared in Preparation Example 1.

[0043] Figure 2 This is a scanning electron microscope image of the modified carbon nanotube / carbon black aggregate prepared in Preparation Example 2.

[0044] Figure 3 This is a scanning electron microscope image of the modified carbon nanotube / carbon black aggregate prepared in Preparation Example 3.

[0045] Figure 4 This is a scanning electron microscope image of the modified carbon nanotube / carbon black aggregate prepared in Preparation Example 4.

[0046] Figure 5 This is a scanning electron microscope image of the modified carbon nanotube / carbon black aggregate prepared in Preparation Example 5.

[0047] Figure 6 This is a scanning electron microscope image of the modified carbon nanotube / carbon black aggregate prepared in Preparation Example 6.

[0048] Figure 7 This is a scanning electron microscope image of the unmodified carbon nanotube / carbon black aggregate provided in Comparative Preparation Example 1. DETAILED DESCRIPTION

[0049] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in combination with the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, but not all of the embodiments. The components of the embodiment of the present invention can be arranged and designed in various different configurations.

[0050] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0051] In a first aspect, the present invention provides a bus tire tread rubber composition, comprising the following components by weight: 100 parts of raw rubber; 45-60 parts of modified carbon nanotube / carbon black aggregate; 1~12 parts of active agent; Accelerator 0.8~6 parts; Vulcanizing agent 0.8~6 parts; 1~5 parts of antioxidant; 0.5~2.5 parts of protective wax; Anti-scorch agent 0~0.3 parts; Processing aids 0~6 parts; Wherein, the modified carbon nanotube / carbon black aggregate is obtained by high-temperature jetting of a modifier and carbon nanotube / carbon black aggregate; the modifier is selected from at least one of the compounds represented by the following formulas I to V: ; Wherein, n and m are each independently selected from positive integers between 1 and 10; M is selected from alkali metals and / or alkaline earth metals; R 1 and R 2 Each independently selected from or , p is selected from a positive integer between 1 and 5.

[0052] The bus tire tread rubber material composition provided by the present invention contains modified carbon nanotube / carbon black aggregates, which not only maintain the large aspect ratio of the carbon nanotubes themselves, but also improve the dispersibility, reinforcement and reaction activity of the carbon nanotubes and carbon black in the rubber matrix and the rubber groups, enhance the interaction between the raw rubber and the filler, and reduce the agglomeration of the filler, thereby further enhancing the mechanical properties of the bus tire tread rubber material composition, reducing heat generation, and improving wear resistance.

[0053] In the bus tire tread rubber composition, the raw rubber is 100 parts; the amount of modified carbon nanotube / carbon black aggregate can be typically but not limited to 45 parts, 50 parts, 55 parts or 60 parts, or any value within the range of 45 parts to 60 parts; the amount of active agent can be typically but not limited to 1 part, 3 parts, 6 parts, 9 parts or 12 parts, or any value within the range of 1 part to 12 parts; the amount of accelerator can be typically but not limited to 0.8 parts, 1.5 parts, 3 parts, 4.5 parts or 6 parts, or any value within the range of 0.8 parts to 6 parts; the amount of vulcanizer can be typically but not limited to 0.8 parts, 1.5 parts, 3 parts, 4.5 parts or 6 parts, or any value within the range of 0.8 parts to 6 parts. It is any value in the range of 0.8 to 6 parts; the amount of antioxidant can be typically but not limited to 1 part, 2 parts, 3 parts, 4 parts or 5 parts, and can also be any value in the range of 1 to 5 parts; the amount of protective wax can be typically but not limited to 0.5 parts, 1 part, 1.5 parts, 2 parts or 2.5 parts, and can also be any value in the range of 0.5 to 2.5 parts; the amount of anti-scorch agent can be typically but not limited to 0 part, 0.1 part, 0.2 part or 0.3 part, and can also be any value in the range of 0 to 0.3 part; the amount of processing aid can be typically but not limited to 0 part, 1 part, 3 parts, 4.5 parts or 6 parts, and can also be any value in the range of 0 to 6 parts.

[0054] It should be noted that “0 parts” means that the substance may not be added to the bus tire tread rubber composition.

[0055] As an optional implementation, n is selected from a positive integer between 1 and 10, for example, it can be 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.

[0056] As an optional implementation, m is selected from a positive integer between 1 and 10, for example, it can be 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.

[0057] As an optional implementation, p is selected from a positive integer between 1 and 5, for example, it can be 1, 2, 3, 4, or 5.

[0058] In the present invention, during the preparation process of the modified carbon nanotube / carbon black aggregate of the present invention, in the presence of the modifier shown in Formula I to Formula V, the carbon nanotube can be more evenly dispersed in the carbon black primary particles by jet technology, significantly improving the dispersion performance of the carbon nanotube. Furthermore, the present invention adds the modified carbon nanotube / carbon black aggregate to the bus tire tread rubber composition, thereby enhancing the interaction between the rubber and the filler, reducing the agglomeration of the filler carbon nanotube / carbon black itself, and providing the mechanical properties and wear resistance of the bus tire tread rubber, while further reducing the heat generation of the bus tire tread rubber.

[0059] It should be noted that the present invention uses a modifier to first modify the carbon nanotube (CNT) / carbon black (CB) aggregates and then add them to the bus tire tread rubber composition. Compared with adding the two to the rubber composition in the form of physical blending at a later stage, the reason why the rubber performance is significantly improved is that: 1. Better dispersibility: The present invention fixes the modifier through chemical bonds, and the graft modification uses covalent bonds to more firmly bind the coupling agent and wrap it on the surface of the aggregate to form a stable surface modification layer. As mentioned above, this chemical bonding can effectively reduce the van der Waals force between aggregates, reduce the tendency to agglomerate, and reduce the risk of CNT breakage, thereby maintaining its original aspect ratio; while it only attaches to the surface of carbon black through physical adsorption or weak interactions (such as hydrogen bonds), and is easy to fall off under the high shear force of rubber processing (such as mixing and extrusion), resulting in the re-agglomeration of carbon black.

[0060] 2. Stronger mechanical properties: The modifier of the present invention not only acts as a "bridge" to form a CNT-CB hybrid structure, but also can connect CNT / CB aggregates at one end and react chemically with rubber molecular chains at the other end to form a strong chemical bonding interface of CNT / CB aggregates-rubber, thereby improving the interfacial bonding ability and making the rubber have stronger mechanical properties; while when only physically mixed, the interface between the modifier and the rubber only relies on physical adsorption or a small amount of reaction, the interfacial bonding strength is low, the stress transfer efficiency is poor, and interfacial debonding is easily caused.

[0061] 3. Higher stability: After grafting modification, the modifier is covalently locked on the surface of the CNT / CB aggregate, and will not migrate or precipitate during rubber processing and use, with high long-term stability; while physically mixed coupling agents may migrate due to poor compatibility with rubber or changes in processing temperature, resulting in local uneven concentration or performance attenuation.

[0062] 4. Higher functionalization efficiency: Chemical grafting can precisely control the coverage density and distribution of the modifier on the surface of CNT / CB aggregates, making full use of the functional groups of the modifier (such as amino groups) to react with rubber; while physical mixed modifiers may be randomly adsorbed on the CNT / CB aggregates or rubber surfaces, and some modifiers will not participate in the subsequent interfacial bonding, resulting in low utilization rate.

[0063] 5. Improve processing performance: Chemically grafted CNT / CB aggregates are easier to disperse in rubber, reducing mixing time and energy consumption, and avoiding CNT breakage due to high shear force (better retention of aspect ratio). If unmodified CNTs require higher shear force to disperse during mixing, it is easy to cause rubber degradation or CNT structure damage.

[0064] As an optional embodiment, the modifier is selected from at least one of the following compounds: .

[0065] As an optional implementation, the carbon nanotube / carbon black aggregates are obtained by powder spraying carbon nanotubes and carbon black primary particles.

[0066] As an optional embodiment, the content of the carbon nanotubes is 1-10% of the total mass of the carbon nanotube / carbon black aggregate.

[0067] As an optional embodiment, the content of the carbon nanotubes can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10% of the total mass of the carbon nanotube / carbon black aggregates, or any value within the range of 1% to 10%.

[0068] As an optional embodiment, the carbon black primary particles are of grade N134. The carbon black primary particles of grade N134 are selected in the present invention because the N134 carbon black has a large specific surface area and high structural performance, which can significantly improve the wear resistance of the rubber. The N134 carbon black has a small particle size and a large specific surface area, and can form a good bond with the rubber molecules, increasing the hardness and elastic modulus of the rubber. This enables the bus tire to better withstand various mechanical stresses during driving, and improves its load-bearing capacity and impact resistance. N134 carbon black can increase the cross-linking density of the rubber, improve the strength and elastic modulus of the rubber, enable the bus tire to better fit the ground during driving, enhance the grip, and is more suitable for use in the bus tire tread rubber composition.

[0069] As an optional embodiment, the amount of the modifier used is 0.8-4% by weight of the carbon black.

[0070] Typically but not limiting, the amount of the modifier can be 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5% or 4% of the weight of the carbon black, or any value within the range of 0.8% to 4%.

[0071] As an optional embodiment, the modified carbon nanotube / carbon black aggregate is prepared by the following steps: (a) Through powder injection, a suspension of carbon nanotubes is sprayed into a carbon black reactor, and the carbon nanotubes and carbon black primary particles combine to form a pre-agglomerate; through the aggregation of carbon black, carbon nanotube / carbon black aggregates are formed.

[0072] (b) combining the modifier with the carbon nanotube / carbon black aggregate by high temperature jet to obtain the modified carbon nanotube / carbon black aggregate.

[0073] In the present invention, the powder injection in step (a) is specifically as follows: the carbon nanotubes are transported to the precisely quantitatively embedded double helix through the mechanical arch breaking device, the airflow arch breaking device and the plowshare stirring device at the bottom of the silo in the storage bin, the carbon nanotubes measured by the weighing system and the precise quantitative spiral enter the mass transfer cavity of the high-speed injection mixer, and are instantly mixed with the injection carrier, i.e., process water. The carbon nanotubes are forced to disperse into the injection carrier during the movement, and are rapidly diffused into a uniform suspension through pressure changes in the diffuser at the tail of the injector, and are transported to the pressure atomization system.

[0074] In the present invention, the combination in step (b) is specifically as follows: adding a modifier and combining it with the flue gas of the suspended carbon nanotubes / carbon black aggregates through high-temperature jet technology; further, after cooling, filtering and collection and separation by the main bag filter, the separated tail gas is used for heating in the tail gas furnace and power generation in the boiler, and finally the powdered carbon nanotubes / carbon black aggregates are stirred with an appropriate amount of water and a binder in a granulator to be granulated, and then the aggregate particles are sent to a rotary dryer for drying, and the modified carbon nanotubes / carbon black aggregates are finally obtained after removing the moisture.

[0075] In the present invention, after the modifier is combined with the carbon nanotube / carbon black aggregate, it can not only maintain the large aspect ratio of the carbon nanotube itself and exert the excellent performance of the carbon nanotube, but also improve the dispersibility, reinforcement and reaction activity of the carbon nanotube and carbon black in the rubber matrix with the rubber group.

[0076] As an optional implementation, in step (a), in the carbon nanotube suspension, the mass proportion of carbon nanotubes is 15-40%, and the remainder is water.

[0077] Typically but not limiting, the mass percentage of carbon nanotubes in the carbon nanotube suspension may be, for example, 15%, 20%, 25%, 30%, 35% or 40%, or any value within the range of 15% to 40%.

[0078] As an optional implementation, in step (a), the injection rate of the carbon nanotube suspension is 50-200 kg / h.

[0079] Typically but not limitatively, the injection rate of the carbon nanotube suspension can be, for example, 50 kg / h, 75 kg / h, 100 kg / h, 125 kg / h, 150 kg / h, 175 kg / h or 200 kg / h, or any value within the range of 50 kg / h to 200 kg / h.

[0080] As an optional embodiment, in step (a), the temperature for combining to form the pre-agglomerate is 800-1000°C.

[0081] Typically but not limiting, the temperature for forming the pre-agglomerate may be, for example, 800°C, 850°C, 900°C, 950°C or 1000°C, or any value within the range of 800°C to 1000°C.

[0082] As an optional embodiment, in step (a), the temperature for forming the carbon nanotube / carbon black aggregates is 600-1000°C.

[0083] Typically but not limiting, the temperature for forming carbon nanotube / carbon black aggregates can be, for example, 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, 950°C or 1000°C, or any value within the range of 600°C to 1000°C.

[0084] As an optional implementation, in step (b), the injection rate of the modifier is 20-100 kg / h.

[0085] Typically but not limiting, the injection rate of the modifier can be, for example, 20 kg / h, 30 kg / h, 40 kg / h, 50 kg / h, 60 kg / h, 70 kg / h, 80 kg / h, 90 kg / h or 100 kg / h, or any value within the range of 20 kg / h to 100 kg / h.

[0086] As an optional embodiment, in step (b), the temperature at which the modifier is combined with the carbon nanotube / carbon black aggregate is 100-480°C.

[0087] Typically but not limiting, the temperature at which the modifier is combined with the carbon nanotube / carbon black aggregate can be, for example, 100°C, 150°C, 200°C, 250°C, 300°C, 350°C, 400°C, 450°C or 480°C, or any value within the range of 100°C to 480°C.

[0088] As an optional embodiment, in step (b), after the modifier is combined with the carbon nanotube / carbon black aggregate, the following post-treatment step is also included: The powder product is obtained through cooling, filtering and collecting and separating; the powder product, a binder and water are mixed, granulated and then dried to obtain the modified carbon nanotube / carbon black aggregate.

[0089] As an optional embodiment, the mass ratio of the powdered product, the binder and water is (80~100):(0.1~2):(0.01~10).

[0090] Typically but not limitatively, the mass ratio of the powdered product, the binder and water can be, for example, 80:0.1:0.01, 80:1:1, 80:2:10, 90:0.5:0.1, 90:1.5:5, 100:0.1:0.01 or 100:2:10, or any value within the range of (80-100):(0.1-2):(0.01-10).

[0091] As an optional embodiment, the binder is selected from lignin and / or molasses.

[0092] As an optional implementation, the particle size of the modified carbon nanotube / carbon black aggregate is 0.1-2.5 μm.

[0093] As an optional embodiment, the raw rubber includes natural rubber as required, and cis-1,4-dimethoxy-1-butyl rubber and / or styrene-butadiene rubber as optional. It should be noted that "required" means that the indispensable raw material in the raw rubber is natural rubber, and "optionally" means that the raw rubber may contain cis-1,4-dimethoxy-1-butyl rubber and / or styrene-butadiene rubber, or may not contain it.

[0094] As an optional embodiment, the weight proportion of cis-1,4-butadiene rubber and / or styrene-butadiene rubber is 20 to 50 parts. Typically but not limiting, the weight proportion of cis-1,4-butadiene rubber and / or styrene-butadiene rubber can be 20, 25, 30, 35, 40, 45 or 50 parts, or any value within the range of 20 to 50 parts.

[0095] As an optional embodiment, the active agent includes stearic acid and / or zinc oxide.

[0096] As an optional embodiment, the accelerator includes accelerator NS.

[0097] As an optional embodiment, the vulcanizing agent includes sulfur.

[0098] As an optional embodiment, the antioxidant includes antioxidant 4020 and / or antioxidant RD.

[0099] As an optional embodiment, the protective wax includes microcrystalline wax.

[0100] As an optional implementation, the anti-scorch agent includes anti-scorch agent CTP.

[0101] As an optional embodiment, the processing aid includes DCPD. DCPD is dicyclopentadiene.

[0102] In a second aspect, the present invention provides a bus tire tread rubber material, which is obtained by mixing the bus tire tread rubber material composition.

[0103] The bus tire tread rubber material provided by the present invention, in view of the advantages of the above composition, enables the bus tire tread rubber material obtained by mixing to have better mechanical properties and wear resistance, and can further reduce the heat generation of the bus tire tread rubber material.

[0104] In a third aspect, the present invention provides a method for preparing a tread rubber material for a bus tire, comprising: (1) Raw rubber, modified carbon nanotube / carbon black aggregate, active agent, antioxidant, protective wax and processing aid are mixed and kneaded to obtain a masterbatch.

[0105] (2) The primary masterbatch, the vulcanizing agent, the accelerator and the anti-scorching agent are mixed and kneaded in two stages to obtain the bus tire tread rubber material.

[0106] The method for preparing the bus tire tread rubber material provided by the invention has continuous process, high mechanization degree and is suitable for large-scale industrial production.

[0107] As an optional embodiment, in step (1), the mixing stage includes the following steps: mixing for 20 to 40 seconds, lifting the top pin, holding for 10 to 15 seconds, and pressing the top pin; mixing to a temperature of 135 to 145°C, lifting the top pin, holding for 10 to 15 seconds, and pressing the top pin; mixing to a temperature of 145 to 155°C for debonding.

[0108] In step (2), the two-stage mixing includes the following steps: after mixing for 10 to 60 seconds, lift the top bolt, hold for 0 to 15 seconds, and press the top bolt; after mixing until the temperature reaches 70 to 85°C, lift the top bolt, hold for 0 to 15 seconds, and press the top bolt; after mixing until the temperature reaches 100 to 120°C, remove the glue.

[0109] In step (1), the mixing stage includes the following steps: mixing for 20 s, 25 s, 30 s, 35 s or 40 s, then lifting the top pin, staying for 10 s, 12 s or 15 s, and then pressing the top pin; continuing mixing until the temperature reaches 135°C, 140°C or 145°C, then lifting the top pin, staying for 10 s, 12 s or 15 s, and then pressing the top pin; and finally mixing until the temperature reaches 145°C, 150°C or 155°C, and then debonding.

[0110] In step (2), the two-stage mixing includes the following steps: after the mixing time can be 10s, 20s, 30s, 40s, 50s or 60s, the top bolt is lifted, the residence time can be 0s, 5s, 10s or 15s, and then the top bolt is pressed; the mixing is continued until the temperature reaches 70°C, 75°C or 85°C, the top bolt is lifted, the residence time can be 0s, 5s, 10s or 15s, and then the top bolt is pressed; and finally, the mixing is performed to discharge the glue when the temperature reaches 100°C, 110°C or 120°C.

[0111] In conjunction with the examples, some embodiments of the present invention are described in detail below. In the absence of conflict, the following examples and features in the examples can be combined with each other. The raw materials used in the examples and comparative examples of the present invention, if no specific conditions are specified, are carried out under normal conditions or conditions recommended by the manufacturer. The reagents or instruments used, if the manufacturer is not specified, are all conventional products that can be purchased commercially.

[0112] The raw materials used in the following examples are shown in Table 1.

[0113] Table 1

[0114] Among them, SUMILINK @ The structural formula of 200 is .

[0115] Preparation Example 1 This preparation example provides a modified carbon nanotube / carbon black aggregate, and the modified carbon nanotube / carbon black aggregate is prepared by the following steps: (a) In a jet system, carbon nanotubes and process water are uniformly mixed by powder injection technology, and the concentration of the carbon nanotube suspension is controlled to be 20wt%; then, the carbon nanotube suspension is sprayed into a carbon black reactor, and the injection flow rate of the carbon nanotube suspension is controlled to be 150kg / h. The temperature in the carbon black reactor is set to 900°C, and the carbon nanotubes and carbon black primary particles N134 are combined to form a pre-agglomerate; then, carbon black is aggregated to form a carbon nanotube / carbon black aggregate; wherein the content of the carbon nanotube is 4% of the total mass of the carbon nanotube / carbon black aggregate; (b) adding 0.8 wt % of sebacic acid dihydrazide to the reactor of step (a) by high temperature jet technology, controlling the injection flow rate of sebacic acid dihydrazide to 80 kg / h, and setting the temperature in the carbon black reactor to 380° C. to combine it with the carbon nanotube / carbon black aggregate to obtain the modified carbon nanotube / carbon black aggregate; cooling, filtering and collecting and separating to obtain a powdery product; mixing the powdery product, lignin and water in a mass ratio of 100:0.1:0.1, granulating and drying to obtain the modifier and carbon nanotube / carbon black aggregate, the scanning electron microscope photo of which is shown in FIG. Figure 1 shown.

[0116] Preparation Example 2 This preparation example provides a modified carbon nanotube / carbon black aggregate, which is different from Example 1 only in that 0.8 wt % of sebacic acid dihydrazide is replaced by 0.8 wt % of isophthalic acid dihydrazide, and the other steps are completely consistent with Example 1. The scanning electron microscope photo is as follows: Figure 2 shown.

[0117] Preparation Example 3 This preparation example provides a modified carbon nanotube / carbon black aggregate, which differs from Example 1 only in that 0.8 wt % of sebacic acid dihydrazide is replaced by 0.8 wt % of SUMILINK @ 200, the other steps are exactly the same as those in Example 1, and the scanning electron microscope photo thereof is as follows Figure 3 shown.

[0118] Preparation Example 4 This preparation example provides a modified carbon nanotube / carbon black aggregate, which is different from Example 1 only in that 0.8 wt % of sebacic acid dihydrazide is replaced by 0.8 wt % of a mixture of sebacic acid dihydrazide and isophthalic acid hydrazide (in the mixture, the mass ratio of sebacic acid dihydrazide to isophthalic acid hydrazide is 1:1), and the other steps are completely consistent with Example 1. The scanning electron microscope photo thereof is shown in FIG. Figure 4 shown.

[0119] Preparation Example 5 This preparation example provides a modified carbon nanotube / carbon black aggregate, which is different from Example 1 only in that 0.8 wt % of sebacic acid dihydrazide is replaced by 0.8 wt % of isophthalic acid hydrazide and SUMILINK @ 200 mixture (in which isophthalic acid hydrazide and SUMILINK @ 200 mass ratio is 1:1), and the other steps are exactly the same as in Example 1. The scanning electron microscope photo is shown in Figure 5 shown.

[0120] Preparation Example 6 This preparation example provides a modified carbon nanotube / carbon black aggregate, which is different from Example 1 only in that 0.8 wt % of sebacic acid dihydrazide is replaced by 0.8 wt % of sebacic acid dihydrazide, isophthalic acid dihydrazide and SUMILINK @ 200 (in which sebacic acid dihydrazide, isophthalic acid dihydrazide and SUMILINK @ 200 has a mass ratio of 2:4:4), and the other steps are exactly the same as in Example 1. The scanning electron microscope photo thereof is shown in FIG. Figure 6 shown.

[0121] Preparation Example 7 This preparation example provides a modified carbon nanotube / carbon black aggregate, which is different from Example 1 only in that the content of sebacic acid dihydrazide is reduced to 0.4 wt %, and the other steps are completely consistent with Example 1.

[0122] Preparation Example 8 This preparation example provides a modified carbon nanotube / carbon black aggregate, which is different from Example 1 only in that the content of sebacic acid dihydrazide is increased to 1.2 wt %, and the other steps are completely consistent with Example 1.

[0123] Preparation Example 9 This preparation example provides a modified carbon nanotube / carbon black aggregate, which differs from Example 1 only in that 0.8 wt % of sebacic acid dihydrazide is replaced by 0.8 wt % of compound I-1, and the other steps are completely consistent with Example 1; wherein the structural formula of compound I-1 is: .

[0124] Preparation Example 10 This preparation example provides a modified carbon nanotube / carbon black aggregate, which is different from Example 1 only in that the content of the carbon nanotubes is 1% of the total mass of the carbon nanotube / carbon black aggregate, and the other steps are completely consistent with Example 1.

[0125] Preparation Example 11 This preparation example provides a modified carbon nanotube / carbon black aggregate, which is different from Example 1 only in that the content of the carbon nanotubes is 10% of the total mass of the carbon nanotube / carbon black aggregate, and the other steps are exactly the same as Example 1.

[0126] Preparation Example 12 This preparation example provides a modified carbon nanotube / carbon black aggregate, which differs from Example 1 only in that the carbon black native particles N134 are replaced with carbon black native particles N660 of equal mass, and the other steps are exactly the same as Example 1.

[0127] Comparative Preparation Example 1 This comparative example provides a carbon nanotube / carbon black aggregate, which differs from Example 1 only in that the modification in step (b) is not performed, and the other steps are completely consistent with Example 1. The scanning electron microscope photo thereof is shown in FIG. Figure 7 shown.

[0128] Test Example 1 Test samples: modified carbon nanotube / carbon black aggregates provided in Preparation Examples 1 to 12, and carbon nanotube / carbon black aggregates provided in Comparative Preparation Example 1.

[0129] Test method: The total specific surface area was measured using the BET (Brunauer-Emmett-Teller) specific surface area method using nitrogen (N 2 ) as adsorbent.

[0130] The pouring density of carbon nanotubes in aggregates is carried out in accordance with the provisions of GB3778-2011.

[0131] Aspect Ratio of CNTs in Aggregates The morphology of CNTs was observed using scanning electron microscopy (SEM), and their aspect ratio was calculated by image analysis.

[0132] The test results are shown in Table 2 and Figures 1 to 6 As shown: Table 2

[0133] As shown in Table 2 above, the total specific surface area of ​​the modified carbon nanotube / carbon black aggregates of the present invention is 45-130 m 2 / g, the pouring density of carbon nanotubes in aggregates is 320~413 kg / m 3 , the aspect ratio of carbon nanotubes in the aggregate can be maintained at 5450~5900.

[0134] Example 1 The present embodiment provides a bus tire tread rubber material, which is obtained by mixing the following bus tire tread rubber material composition; wherein the bus tire tread rubber material composition comprises the following components in parts by weight, as shown in the following Table 3.

[0135] Table 3

[0136] The bus tire tread rubber material described in this embodiment is prepared by the following steps: (1) One-stage mixing: start the internal mixer, set the rotor speed of the internal mixer to 50 rpm, the mixing pressure to 5.5 MPa, the cooling water temperature to 35°C, the rotor temperature to 35°C, add the raw rubber, modified carbon nanotube / carbon black aggregate, activator, antioxidant, additive and protective wax, mix for 30 seconds, lift the top plug, hold for 12 seconds, press the top plug, mix until the temperature reaches 140°C, lift the top plug, hold for 12 seconds, press the top plug, and wait until the temperature reaches 150°C before discharging the rubber to obtain a one-stage masterbatch.

[0137] (2) Second stage mixing: start the internal mixer, set the rotor speed of the internal mixer to 25 rpm, the mixing pressure to 5.0 MPa, the cooling water temperature to 35°C, the rotor temperature to 40°C, add the first stage masterbatch, vulcanizer, accelerator and anti-scorch agent, mix for 35 seconds, lift the top plug, stay for 8 seconds and then press the top plug, mix until the temperature reaches 78°C, lift the top plug, stay for 7 seconds and then press the top plug, when the rubber material temperature reaches 110°C, lift the plug and discharge the rubber, and cool the lower sheet to room temperature to obtain the bus tire tread rubber material.

[0138] Example 2 This embodiment provides a bus tire tread rubber material, which differs from Example 1 only in that the modified carbon nanotube / carbon black aggregate provided in Preparation Example 1 is replaced with an equal weight portion of the modified carbon nanotube / carbon black aggregate provided in Preparation Example 2.

[0139] Example 3 This embodiment provides a bus tire tread rubber material, which is different from Example 1 only in that the modified carbon nanotube / carbon black aggregate provided in Preparation Example 1 is replaced with an equal weight portion of the modified carbon nanotube / carbon black aggregate provided in Preparation Example 3.

[0140] Example 4 This embodiment provides a bus tire tread rubber material, which differs from Example 1 only in that the modified carbon nanotube / carbon black aggregate provided in Preparation Example 1 is replaced with an equal weight portion of the modified carbon nanotube / carbon black aggregate provided in Preparation Example 4.

[0141] Example 5 This embodiment provides a bus tire tread rubber material, which differs from Example 1 only in that the modified carbon nanotube / carbon black aggregate provided in Preparation Example 1 is replaced with an equal weight portion of the modified carbon nanotube / carbon black aggregate provided in Preparation Example 5.

[0142] Example 6 This embodiment provides a bus tire tread rubber material, which differs from Example 1 only in that the modified carbon nanotube / carbon black aggregate provided in Preparation Example 1 is replaced with an equal weight portion of the modified carbon nanotube / carbon black aggregate provided in Preparation Example 6.

[0143] Example 7 This embodiment provides a bus tire tread rubber material, which is different from Example 1 only in that the raw rubber is a mixture of 90 parts of natural rubber and 10 parts of butadiene rubber; at the same time, the modified carbon nanotube / carbon black aggregate provided in Preparation Example 1 is replaced by an equal weight portion of the modified carbon nanotube / carbon black aggregate provided in Preparation Example 6.

[0144] Example 8 This embodiment provides a bus tire tread rubber material, which is different from Example 1 only in that the modified carbon nanotube / carbon black aggregate provided in Preparation Example 1 is replaced with an equal weight portion of the modified carbon nanotube / carbon black aggregate provided in Preparation Example 7.

[0145] Example 9 This embodiment provides a bus tire tread rubber material, which is different from Example 1 only in that the modified carbon nanotube / carbon black aggregate provided in Preparation Example 1 is replaced with an equal weight portion of the modified carbon nanotube / carbon black aggregate provided in Preparation Example 8.

[0146] Example 10 This embodiment provides a bus tire tread rubber material, which differs from Example 1 only in that the modified carbon nanotube / carbon black aggregate provided in Preparation Example 1 is replaced with an equal weight portion of the modified carbon nanotube / carbon black aggregate provided in Preparation Example 9.

[0147] Embodiment 11 This embodiment provides a bus tire tread rubber material, which is different from Example 1 only in that the modified carbon nanotube / carbon black aggregate provided in Preparation Example 1 is replaced with an equal weight portion of the modified carbon nanotube / carbon black aggregate provided in Preparation Example 10.

[0148] Example 12 This embodiment provides a bus tire tread rubber material, which differs from Example 1 only in that the modified carbon nanotube / carbon black aggregate provided in Preparation Example 1 is replaced with an equal weight portion of the modified carbon nanotube / carbon black aggregate provided in Preparation Example 11.

[0149] Example 13 This embodiment provides a bus tire tread rubber material, which differs from Example 1 only in that the modified carbon nanotube / carbon black aggregate provided in Preparation Example 1 is replaced with an equal weight portion of the modified carbon nanotube / carbon black aggregate provided in Preparation Example 12.

[0150] Embodiment 14 This embodiment provides a bus tire tread rubber material, which is different from the embodiment 1 only in that the amount of modified carbon nanotube / carbon black aggregate is 51 parts, and the raw materials also include 1 part of sebacic acid dihydrazide.

[0151] Comparative Example 1 This comparative example provides a bus tire tread rubber material, which is made using a corresponding bus tire tread rubber material composition. The bus tire tread rubber material composition includes the following components in parts by weight, as shown in Table 4 below.

[0152] Table 4

[0153] The above-mentioned bus tire tread rubber material is prepared by the following steps: (1) One-stage mixing: start the internal mixer, set the rotor speed of the internal mixer to 50 rpm, the mixing pressure to 5.5 MPa, the cooling water temperature to 35°C, the rotor temperature to 35°C, add the raw rubber, carbon nanotubes, carbon black, modifier, activator, antioxidant, additive and protective wax, mix for 30 seconds, lift the top plug, stay for 12 seconds, press the top plug, mix until the temperature reaches 140°C, lift the top plug, stay for 12 seconds, press the top plug, and when the temperature reaches 150°C, discharge the rubber to obtain a one-stage masterbatch.

[0154] (2) The preparation steps are the same as those in Example 1.

[0155] Comparative Example 2 This comparative example provides a bus tire tread rubber material, which is different from comparative example 1 only in that sebacic acid dihydrazide is replaced by isophthalic dihydrazide, and other steps and raw materials are completely consistent with comparative example 1.

[0156] Comparative Example 3 This comparative example provides a bus tire tread rubber material, which is different from comparative example 1 only in that sebacic acid dihydrazide is replaced by SUMILINK@200, and the other steps and raw materials are completely consistent with comparative example 1.

[0157] Comparative Example 4 This comparative example provides a bus tire tread rubber material, which is different from comparative example 1 only in that 0.5 parts of isophthalic acid hydrazide and 0.5 parts of sebacic acid dihydrazide are used to replace 1 part of sebacic acid dihydrazide, and other steps and raw materials are completely consistent with comparative example 1.

[0158] Comparative Example 5 This comparative example provides a bus tire tread rubber material, which is different from comparative example 1 only in that 0.5 parts of isophthalic acid dihydrazide and 0.5 parts of SUMILINK@200 are used to replace 1 part of sebacic acid dihydrazide, and other steps and raw materials are completely consistent with comparative example 1.

[0159] Comparative Example 6 This comparative example provides a bus tire tread rubber material, which is different from comparative example 1 only in that 0.4 parts of isophthalic acid hydrazide, 0.2 parts of sebacic acid dihydrazide, and 0.4 parts of SUMILINK@200 are used to replace 1 part of sebacic acid dihydrazide, and other steps and raw materials are completely consistent with comparative example 1.

[0160] Comparative Example 7 This comparative example provides a bus tire tread rubber material, which is different from comparative example 2 only in that 30 parts of cis-1,2-butadiene rubber and 10 parts of styrene-butadiene rubber are used to replace 40 parts of cis-1,2-butadiene rubber, and other steps and raw materials are completely consistent with comparative example 2.

[0161] Comparative Example 8 This comparative example provides a bus tire tread rubber material, which is different from comparative example 1 only in that sebacic acid dihydrazide is not added, and other steps and raw materials are completely consistent with comparative example 1.

[0162] Comparative Example 9 This comparative example provides a bus tire tread rubber material, which is different from Example 1 only in that the modified carbon nanotube / carbon black aggregate provided in Preparation Example 1 is replaced with 51 parts of carbon nanotube / carbon black aggregate provided in Comparative Preparation Example 1, and the raw materials also include 1 part of sebacic acid dihydrazide.

[0163] Comparative Example 10 This comparative example provides a bus tire tread rubber material, which differs from Example 1 only in that the modified carbon nanotube / carbon black aggregate provided in Preparation Example 1 is replaced with an equal weight portion of the carbon nanotube / carbon black aggregate provided in Comparative Preparation Example 1.

[0164] Test Example 2 Test samples: The performance of the bus tire tread rubber materials provided in Examples 1 to 14 and Comparative Examples 1 to 10 was tested.

[0165] Specifically, it includes 300% tensile stress M300, tear burst force TB, elongation at break EB%, storage modulus E' at 60℃, tangent value of loss angle tanδ / 60℃ at 60℃ and Akron abrasion.

[0166] 300% elongation stress M300 is carried out in accordance with the provisions of GB / T528-2009; tear burst force TB is carried out in accordance with the provisions of GB / T528-2009; elongation at break EB% is carried out in accordance with the provisions of GB / T528-2009; storage modulus E' is carried out under the conditions of 10Hz, 7%±2; the tangent value of the loss angle at 60℃ tanδ / 60℃ is carried out in accordance with the provisions of GB / T528-2009; Akron abrasion is carried out in accordance with the provisions of GB / T1689-2014.

[0167] The test results are shown in Table 5 below: Table 5

[0168] As can be seen from Table 5, in the above-mentioned Comparative Examples 1 and 8, adding a modifier to the carbon black formula can reduce heat generation by 10%. It can be seen from Comparative Examples 1, 8 and Example 1 that by jet technology, adding a modifier and carbon nanotube / N134 carbon black aggregates to produce carbon nanotube / N134 carbon black aggregates can further generate heat, which is 18.2% lower than that without adding a modifier, and 9.5% lower than that of Comparative Example 1; and it can be seen from Comparative Examples 1, 8 and Example 1 that the addition of a modifier can not only reduce heat generation, but also improve wear, especially when the modifier and carbon nanotube / N134 carbon black aggregates are added to produce carbon nanotube / N134 carbon black aggregates, the wear resistance is improved by 30.8%. It can be seen from the comparative examples and examples that different modifiers can contribute to heat generation when used alone or in combination. Comparison of Comparative Examples 1-7 and 8 shows that the heat generation tanδ is significantly reduced. From Comparative Example 1 and Example 14, it can be seen that the heat generation tanδ of carbon nanotubes / N134 carbon black aggregates is reduced compared with carbon black direct carbon nanotubes, and the wear resistance is almost unchanged; compared with Example 1, the addition of carbon nanotubes / N134 carbon black aggregates produced by modifiers and carbon nanotubes / N134 carbon black aggregates can further generate heat while improving wear resistance. From Example 1 and Comparative Example 9, it can be seen that the mechanical properties of the rubber product obtained by first compounding the modifier with carbon nanotubes / carbon black aggregates (tensile strength and elongation at break of vulcanized rubber) are significantly improved compared to adding them to the rubber composition in the form of physical blending, and the heat generation (loss factor of vulcanized rubber at 60°C) is significantly reduced.

[0169] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A modified carbon nanotube / carbon black aggregate as a filler in the preparation of a bus tire tread rubber composition, characterized in that: The modified carbon nanotube / carbon black aggregate is obtained by high-temperature jetting of a modifier and carbon nanotube / carbon black aggregate; the modifier is selected from at least one of the compounds represented by the following formulas I to V: ； Wherein, n and m are each independently selected from a positive integer between 1 and 10; M is selected from an alkali metal and / or an alkaline earth metal; R1 and R2 are each independently selected from or , p is selected from a positive integer between 1 and 5.

2. A bus tire tread rubber composition, characterized in that: The following components are included by weight: 100 parts of raw rubber; 45-60 parts of modified carbon nanotube / carbon black aggregate; 1~12 parts of active agent; Accelerator 0.8~6 parts; Vulcanizing agent 0.8~6 parts; 1~5 parts of antioxidant; 0.5~2.5 parts of protective wax; Anti-scorch agent 0~0.3 parts; Processing aids 0~6 parts; Wherein, the modified carbon nanotube / carbon black aggregate is obtained by high-temperature jetting of a modifier and carbon nanotube / carbon black aggregate; the modifier is selected from at least one of the compounds represented by the following formulas I to V: ； Wherein, n and m are each independently selected from a positive integer between 1 and 10; M is selected from an alkali metal and / or an alkaline earth metal; R1 and R2 are each independently selected from or , p is selected from a positive integer between 1 and 5.

3. The bus tire tread rubber composition according to claim 2, characterized in that: The modifier is selected from at least one of the following compounds: ; And / or, the carbon nanotube / carbon black aggregates are obtained by powder injection of carbon nanotubes and carbon black primary particles; and / or, the content of the carbon nanotubes is 1-10% of the total mass of the carbon nanotube / carbon black aggregate; And / or, the grade of the carbon black primary particles is N134; And / or, the amount of the modifier is 0.8-4% by weight of the carbon black.

4. The bus tire tread rubber composition according to claim 2, characterized in that: The modified carbon nanotube / carbon black aggregate is prepared by the following steps: (a) Spraying a suspension of carbon nanotubes into a carbon black reaction furnace through powder injection, the carbon nanotubes and carbon black primary particles are combined to form a pre-agglomerate; and carbon black is aggregated to form a carbon nanotube / carbon black aggregate; (b) combining the modifier with the carbon nanotube / carbon black aggregate by high temperature jet to obtain the modified carbon nanotube / carbon black aggregate.

5. The bus tire tread rubber composition according to claim 4, characterized in that: In step (a), in the carbon nanotube suspension, the mass proportion of carbon nanotubes is 15-40%, and the balance is water; And / or, in step (a), the injection rate of the carbon nanotube suspension is 50-200 kg / h; And / or, in step (a), the temperature of combining to form the pre-agglomerated body is 800-1000°C; And / or, in step (a), the temperature for forming the carbon nanotube / carbon black aggregate is 600-1000°C.

6. The bus tire tread rubber composition according to claim 4, characterized in that: In step (b), the injection rate of the modifier is 20-100 kg / h; and / or, in step (b), the temperature at which the modifier combines with the carbon nanotube / carbon black aggregate is 100-480°C; And / or, in step (b), after the modifier is combined with the carbon nanotube / carbon black aggregate, the following post-treatment step is also included: After cooling, filtering and collecting and separating, a powdery product is obtained; the powdery product, a binder and water are mixed, granulated and then dried to obtain the modified carbon nanotube / carbon black aggregate; And / or, the mass ratio of the powdered product, the binder and water is (80-100):(0.1-2):(0.01-10); and / or, the binder is selected from lignin and / or molasses; And / or, the particle size of the modified carbon nanotube / carbon black aggregate is 0.1-2.5 μm.

7. The bus tire tread rubber composition according to any one of claims 2 to 6, characterized in that: The raw rubber includes natural rubber, and optionally butadiene rubber and / or styrene-butadiene rubber; And / or, the weight proportion of butadiene rubber and / or styrene butadiene rubber is 20 to 50 parts; and / or, the active agent comprises stearic acid and / or zinc oxide; and / or, the accelerator comprises accelerator NS; and / or, the vulcanizing agent comprises sulfur; And / or, the antioxidant includes antioxidant 4020 and / or antioxidant RD; and / or, the protective wax comprises microcrystalline wax; And / or, the anti-scorch agent includes anti-scorch agent CTP; And / or, the processing aid includes DCPD.

8. A bus tire tread rubber material, characterized in that: The method is obtained by mixing the bus tire tread rubber composition according to any one of claims 2 to 7.

9. A method for preparing a bus tire tread rubber material according to claim 8, characterized in that: The preparation method comprises: (1) mixing raw rubber, modified carbon nanotube / carbon black aggregate, active agent, antioxidant, protective wax and processing aid, and performing a mixing step to obtain a masterbatch; (2) The primary masterbatch, the vulcanizing agent, the accelerator and the anti-scorching agent are mixed and kneaded in two stages to obtain the bus tire tread rubber material.

10. The method for preparing a tread rubber material for a bus tire according to claim 9, characterized in that: In step (1), the mixing stage includes the following steps: mixing for 20 to 40 seconds, lifting the top pin, staying for 10 to 15 seconds, and pressing the top pin; mixing until the temperature reaches 135 to 145°C, lifting the top pin, staying for 10 to 15 seconds, and pressing the top pin; mixing until the temperature reaches 145 to 155°C, and then removing the glue; In step (2), the two-stage mixing includes the following steps: after mixing for 10 to 60 seconds, lift the top bolt, hold for 0 to 15 seconds, and press the top bolt; after mixing until the temperature reaches 70 to 85°C, lift the top bolt, hold for 0 to 15 seconds, and press the top bolt; after mixing until the temperature reaches 100 to 120°C, remove the glue.

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