Wear-resistant and high-temperature-resistant tread rubber composition and mixing method thereof

Abstract

The invention relates to the technical field of tire rubber manufacturing, and discloses a wear-resistant and high-temperature-resistant tread rubber composition and a mixing method thereof.The rubber composition is prepared from, by weight, 65-80 parts of rubber, 40-60 parts of filler A, 3-6 parts of an activating agent, 2-4 parts of a vulcanizing agent, 2-5 parts of an anti-aging agent and 0.5-1.5 parts of tear-resistant resin through mixing, 15-45 parts of a nano reinforced composite material and 0.5-2 parts of microcrystalline wax; the nano reinforced composite material is prepared by mixing butadiene rubber, a filler B, organic sulfide and dihydrazide. Through non-homogeneous distribution of the filler, the nano reinforced composite material can absorb a large amount of energy in the stretching process, and the high temperature resistance and wear resistance of the tread rubber composition can be obviously improved.

Description

Technical Field

[0001] This invention relates to the field of tire rubber manufacturing technology, and more specifically, to a wear-resistant and high-temperature resistant tread rubber composition and its mixing method. Background Technology

[0002] The tread compound, located on the outermost layer of the tire and in direct contact with the road surface, directly determines the tire's service life and safety limits based on its wear resistance, tear resistance, grip, and heat generation. Especially under heavy loads, long downhill slopes, or high-speed conditions, the tread compound continuously generates heat under repeated compression-shear-tension dynamic loads, often reaching internal temperatures of approximately 60–80°C or even higher. Increased temperature leads to a decrease in the rubber matrix modulus, relaxation of reinforcing structures, and increased dynamic wear, resulting in accelerated wear, further increased heat generation, and easier initiation and propagation of fatigue cracks, ultimately causing abnormal tread wear, block spalling, or durability failure. Therefore, achieving synergistic optimization of the tread compound—maintaining modulus at high temperatures, significantly improving wear resistance, and controlling heat generation—while ensuring processing safety and overall mechanical properties has always been a key challenge in tire formulation and compounding processes.

[0003] To address the issues of high-temperature performance degradation and insufficient wear resistance in tire tread compounds, existing technologies generally propose improvement solutions from the perspectives of rubber matrix design, crosslinking network regulation, filler system optimization, and the introduction of functional additives. For example, Chinese patent document CN115572416B discloses a high-temperature resistant tire tread compound and its preparation method. By selecting a natural rubber and a specific polybutadiene system in the tread compound formulation, and combining vulcanization conditions and crosslinking structure control (such as crosslinking density and different sulfur bond ratios), it alleviates the significant decrease in elongation, storage modulus, and hardness at high temperatures, thereby improving high-temperature modulus retention while also considering wear resistance and rolling resistance. The technical focus of this type of solution lies in the overall optimization of the "matrix-vulcanization network," which can improve the load-bearing capacity and performance stability of the tread compound under high-temperature conditions to a certain extent. However, from an engineering application perspective, this type of improvement, which focuses on the crosslinking network and matrix system, usually still centers on conventional carbon black / silica reinforcement systems, with the reinforcement structure leaning towards a "uniformly dispersed, average-reinforced" model. When the operating conditions become more demanding (higher temperature, higher frequency, greater load), if it is necessary to further improve the high temperature modulus and wear resistance, it is often tempted to increase the amount of filler or increase the crosslinking density. However, this can easily lead to engineering contradictions such as increased Mooney viscosity, increased difficulty in mixing and dispersion, increased processing temperature rise and risk of scorching, and difficulty in further reducing dynamic loss and heat generation.

[0004] On the other hand, with the increasing application of nanomaterials in rubber reinforcement, carbon nanotubes and graphene / graphene oxide are being used to improve reinforcement efficiency and wear resistance. Chinese patent document CN105860133A proposes a carbon nanotube masterbatch and its application in tire treads. The approach involves first dispersing and processing carbon nanotubes in a polymer system (e.g., grinding and shaving), then co-blending them with rubber masterbatch and carbon black to obtain the carbon nanotube masterbatch, which is then used in tire treads to improve wear resistance and other properties. The starting point of this route is to reduce the agglomeration and uneven dispersion caused by direct addition of carbon nanotubes through a "masterbatch / masterbatch" method, thereby improving the effective utilization of nanofillers in rubber. However, the industrial application of nanofiller systems in tread rubber still faces typical challenges: First, nanofillers are prone to secondary agglomeration or network disruption during high-shear mixing, leading to fluctuations in reinforcement effects. Second, without targeted interfacial chemical bonding and energy dissipation path design, while nanofillers may improve room temperature strength, they may not be able to maintain the reinforcing structure under high-temperature dynamic conditions, and may even lead to increased dynamic losses and heat generation. Third, nanofillers and conventional fillers (carbon black / silica) have competitive adsorption and distribution coupling problems within the system, easily forming a "seemingly uniform but inefficient" reinforcing morphology, making it difficult to simultaneously achieve high modulus maintenance and significant improvement in wear resistance at high temperatures. Therefore, simply relying on the "addition of nano-masterbatch" approach is often insufficient to stably solve the composite goal of high-temperature wear resistance.

[0005] Another type of existing technology emphasizes improving high-temperature durability by reducing dynamic internal friction and heat generation through functional additives. Chinese patent document CN109251375A discloses "A radial tire tread rubber composition containing isophthalic acid hydrazine and its preparation method," which introduces isophthalic acid hydrazine into a rubber (such as polyisoprene) and carbon black / silica system, combined with silane coupling agents and conventional vulcanization systems, to improve the overall performance of the tread rubber. The technical focus of this type of solution is to influence the dynamic loss and processing / vulcanization behavior of the system through hydrazine compounds, thereby reducing heat generation and improving mechanical retention to a certain extent. However, from the perspective of synergistic effects of "maintaining high-temperature modulus and significantly improving wear resistance," the hydrazide-based additive route may still have limitations: First, the improvement in heat generation and dynamic loss caused by hydrazides does not necessarily translate into a significant enhancement of the reinforcing structure at high temperatures; second, if the filler-rubber interface bonding is insufficient or the filler structure is uncontrollable, the load-bearing capacity at high temperatures may still rapidly decline, and wear will still be difficult to reduce significantly; third, when further increasing the filler dosage to pursue wear resistance, engineering problems such as mixing dispersion, viscosity, and temperature rise control may be introduced. Therefore, relying solely on a homogeneous strategy of "functional additives and conventional reinforcing systems" is usually insufficient to simultaneously push wear resistance, modulus maintenance, and heat generation control to higher levels under harsh high-temperature conditions.

[0006] In summary, while existing technologies have proposed improvements in various directions, including (i) crosslinking network and matrix design, (ii) masterbatch reinforcement with nanofillers, and (iii) heat reduction using hydrazide-based functional additives, they still share common shortcomings in meeting the comprehensive requirements of high-temperature wear resistance in tread rubber: a lack of a controllable reinforcing structure that is "more conducive to high-temperature load-bearing and wear resistance" during the mixing process. Specifically, existing solutions often employ a uniform dispersion approach of "direct or masterbatch addition of nanofillers," or rely primarily on overall network regulation and additive effects, making it difficult to stably form structural units that can sustain load-bearing, absorb strain energy, and inhibit wear particle peeling during high-temperature tensile / shear processes. Furthermore, there is a lack of systematic design regarding the spatial distribution relationship and interfacial synergy between the nano-reinforcing phase and the conventional filler phase. Against this backdrop, this invention proposes a method of prefabricating nano-reinforced composite materials and introducing them in a specific mixing stage to achieve heterogeneous filler distribution and interfacial synergistic reinforcement, aiming to obtain more stable high-temperature modulus retention and more significant wear resistance improvement in the 60–100℃ temperature range, thereby meeting the comprehensive performance requirements of tread rubber under harsh high-temperature conditions. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a wear-resistant and high-temperature tread rubber composition and its mixing method. By employing the heterogeneous distribution of fillers and nano-reinforced wear-resistant composite materials, the modulus and mechanical properties of the rubber composition at high temperatures are improved, thereby further enhancing the wear resistance of the rubber composition.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A wear-resistant and high-temperature resistant tire tread rubber composition, wherein the rubber composition is prepared by mixing raw materials comprising the following components in parts by weight: Rubber A 65-80 parts, Packing material A, 40-60 parts. Activator 3.0-6.0 parts, 2.0-4.0 parts of vulcanizing agent. Anti-aging agent 2.0-5.0 parts, Nano-reinforced composite materials 15-45, The rubber is natural rubber and / or synthetic isoprene rubber, and filler A is carbon black and / or silica. The nano-reinforced composite material is prepared by mixing raw materials comprising the following components in parts by weight: Rubber B20-40 parts, Packing material B, 1.0-10 parts. Organosilicon polysulfide compounds, 1.0-4.0 parts. 0.4-2.0 parts of diacylhydrazide compound; Rubber B is selected from butadiene rubber; the total weight of rubber A and rubber B is 100 parts by weight, and the filler B is one or more of carbon nanotubes, graphene, and carbon black.

[0009] Preferably, the rubber composition is prepared by mixing raw materials comprising the following components in parts by weight: Rubber A 70-80 parts, 50-60 parts of filler A Activator 4.0-6.0 parts, 2.0-3.0 parts of vulcanizing agent, Anti-aging agent 2.0-4.0 parts, Nano-reinforced composite materials 25-40, The nano-reinforced composite material is prepared by mixing raw materials comprising the following components in parts by weight: Rubber B20-35 parts, Packing material B, 2.0-5.0 parts. 1.0-2.5 parts of organosilicon polysulfide compounds, 0.5-1.5 parts of dihydrazide compound.

[0010] Preferably, the carbon black in filler A is one or two of N375, N330, N339, N347, and N326.

[0011] Preferably, the carbon nanotubes in filler B are arrayed, the carbon black is N375, N330, N339, N347 or N326, and the graphene is 2-10 layers of graphene oxide.

[0012] Preferably, the organosilicon polysulfide is selected from one or more of γ-mercaptopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, bis(3-mercaptopropyl)tetrasulfide, bis(3-mercaptopropyl)disulfide, mercaptoethyltriethoxysilane, mercaptopropylsiloxane copolymer, methylthiol silane, dimercaptoethylsilane, tetra(mercaptopropyl)silane, and bis(γ-triethoxysilylpropyl)sulfide.

[0013] Preferably, the activator is selected from one or more of zinc oxide, stearic acid, and zinc stearate; And / or, the antioxidant is selected from one or more of antioxidant 4010, antioxidant 4020, antioxidant RD, 2-mercaptobenzothiazole, and antioxidant TMQ; And / or, the vulcanizing agent is selected from one or more of sulfur, dicumyl peroxide, vulcanization accelerator NS, vulcanization accelerator CZ, and tetramethylthiuram disulfide.

[0014] Preferably, the raw materials for the rubber composition also include 0.5-1.5 parts of tear-resistant resin and 0.5-2 parts of microcrystalline wax.

[0015] Preferably, the tear-resistant resin is one or more of polycyclopentadiene resin, C5 modified resin, and C9 modified resin.

[0016] Preferably, the preparation method of the nano-reinforced wear-resistant composite material includes the following steps: starting the internal mixer, setting the speed to 30-45 rpm, adding cis-butadiene rubber, filler and organosilicon polysulfide compound, mixing for 25-40 seconds, adding dihydrazide compound, continuing to mix for 1-2.5 minutes, discharging the glue, and obtaining the nano-reinforced composite material.

[0017] Furthermore, the present invention also provides a method for preparing the rubber composition, comprising the following steps: 1) First stage mixing: Start the internal mixer, set the speed to 45-55 rpm, add rubber, filler A, activator, antioxidant, tear-resistant resin and microcrystalline wax, mix for 30-50 seconds, then mix for 20-30 seconds with the plunger lifted and pressed, and then mix until 150-165℃ to discharge the glue to obtain masterbatch 1. 2) Two-stage mixing: Start the internal mixer, set the speed to 25-35 rpm, add masterbatch 1 and nano-reinforced composite material, mix for 30-50 seconds, then mix for 20-30 seconds with the plunger lifted and pressed, and finally mix at 135-145℃ to discharge the glue to obtain masterbatch 2. 3) Vulcanization: Start the internal mixer, set the speed to 25-35 rpm, add masterbatch 2 and vulcanizing agent first, mix for 30-50 seconds, then mix for 20-30 seconds with the plunger lifted and pressed, and finally mix until 105-115℃ to discharge the rubber, thus obtaining a wear-resistant and high-temperature resistant rubber composition.

[0018] By employing the aforementioned technical solution, this invention, through the heterogeneous distribution of fillers, enables the nano-reinforced composite material to absorb a large amount of energy during stretching, thereby significantly improving the high-temperature resistance and wear resistance of the tread rubber composition. The following significant technical effects are observed: 1. Significantly Improved Wear Resistance: This invention optimizes the distribution characteristics of fillers in the rubber matrix by introducing nano-reinforced composite materials. During stretching, the nanofillers can effectively absorb strain energy, significantly improving the rubber material's resistance to damage, thereby enhancing the wear resistance of the tread rubber and extending the tire's service life.

[0019] 2. High-Temperature Performance Optimization: The nano-reinforced composite material provides excellent modulus retention under high-temperature conditions, ensuring good mechanical properties of the tread rubber in an operating environment of 60-80℃. The tear strength and dynamic modulus of the material decrease by more than 30% at high temperatures compared to traditional materials, significantly improving the high-temperature stability and safety of the tire.

[0020] 3. Enhanced Dynamic Fatigue Performance: Through the heterogeneous distribution design of the filler, the rubber composition of this invention effectively reduces the heat generation during dynamic driving, significantly delaying the aging process of the rubber. The fatigue resistance of the rubber under dynamic compression deformation (>10Hz) conditions is enhanced, making it particularly suitable for high-speed driving scenarios.

[0021] 4. Balance of mechanical properties: The chemical modification of dihydrazide compounds enhances the interfacial bonding between nanofillers and the rubber matrix, while optimizing the activity of end groups in the rubber, further improving the strength and flexibility of the rubber compound, and achieving a balance between tensile strength, abrasion resistance and dynamic performance.

[0022] 5. Significantly Reduced Heat Generation: Diazidamide compounds can chemically react with the aldehyde, carboxyl, and carbonyl groups at the ends of rubber, effectively reducing the activity of free radical ends and decreasing internal friction and heat generation during dynamic deformation. Compared to traditional rubber compositions, the temperature rise of the material of this invention is reduced by 20%-30%, further improving tire durability.

[0023] 6. Synergistic Improvement of Multiple Performances: This invention successfully resolves the contradiction between grip and rolling resistance in traditional rubber formulations while improving wear resistance and high-temperature resistance. Tires made using the rubber composition of this invention not only have higher driving safety but also significantly reduce rolling resistance and improve fuel efficiency.

[0024] In summary, through material innovation and process optimization, this invention not only significantly improves the wear resistance, high-temperature resistance, and dynamic fatigue performance of tires, but also achieves synergistic improvement of multiple properties, providing a brand-new solution for the preparation of tire rubber. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the SEM (Scanning Electron Microscopy) of the rubber composition in Example 1. The black part in the figure represents the nano-reinforced composite material.

[0026] Figure 2 This is a schematic diagram of the SEM (Scanning Electron Microscopy) of the rubber composition in Comparative Example 1. Detailed Implementation

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present invention.

[0028] I. Terms and Definitions Rubber A: refers to the main rubber phase in the tread rubber composition, selected from natural rubber (NR) and / or synthetic isoprene rubber (IR). In the embodiments of the present invention, natural rubber is preferred, as it provides higher tear strength and processing performance.

[0029] Rubber B: refers to the rubber phase used to prepare "nano-reinforced composite materials", preferably cis-butadiene rubber (BR), which is used to support nanofillers and construct "locally enriched reinforcing phases".

[0030] Filler A: Refers to the conventional reinforcing filler in the tread masterbatch, selected from carbon black and / or silica. Abrasion-resistant carbon black (such as N375, N330, N339, N347, N326, etc.) is preferred, and it can also be compounded with silica to optimize rolling resistance and heat generation.

[0031] Filler B: refers to the nano / micro / nano reinforcing filler in nano-reinforced composite materials, selected from one or more of carbon nanotubes, graphene, and carbon black; preferably arrayed / multi-walled carbon nanotubes (MWCNTs) and / or 2–10 layers of graphene oxide (GO), or can be synergistically formed with a small amount of carbon black to form a multi-scale network.

[0032] Organosilicon polysulfides: These refer to coupling / reactive auxiliaries with silane end groups and polysulfide bonds (such as bis[γ-(triethoxysilyl)propyl]tetrasulfide, etc.), whose function is: Promotes interfacial bonding between the surface of filler B and the rubber segments; It participates in cross-linking or interfacial bridging during the formation of the vulcanization network, thereby improving high-temperature modulus retention and fatigue resistance.

[0033] Diacylhydrazide compounds: These refer to reactive modifying components with the —CONHNHCO— structure (such as sebacic acid diacylhydrazide), whose function is: It reacts with carbonyl groups produced by rubber end / oxidation or forms hydrogen bonds / coordination; The formation of "energy dissipation / strain absorption points" at the interface of nanofillers reduces internal heat generation and improves high-temperature mechanical properties.

[0034] Nano-reinforced composite materials refer to the "locally enriched reinforcing phase" obtained by pre-mixing the components (rubber B, filler B, organosilicon polysulfide compound, and dihydrazide compound) as defined in the claims in an internal mixer. In the final mix, it is introduced into the masterbatch at a ratio of 15–45 parts, thereby forming a heterogeneous distribution of fillers: conventional reinforcing fillers (filler A) are continuously dispersed phases, while nano-reinforced composite materials are distributed in the form of "island-like / blocky enriched phases," both of which jointly improve high-temperature modulus and wear resistance.

[0035] Bolt lifting / pressing: refers to the operation of raising and lowering the top bolt during the mixing process to adjust the shear and filling state by adjusting the packing dispersion and temperature rise rate.

[0036] Master Rubber 1 and Master Rubber 2: These correspond to the unvulcanized rubber compounds after the first and second stages of mixing, respectively. Master Rubber 2, after adding a vulcanizing agent in the vulcanization stage, yields the final compound (vulcanizable rubber).

[0037] II. Raw Materials and Sources To facilitate reproduction, typical raw materials and their sources used in the embodiments of this invention are given (materials of equivalent grade or performance can be substituted): Natural rubber (NR): Thai No. 20 standard rubber; Butadiene rubber (BR): Neodymium-based butadiene BR-544NP (Nizhnekamsk, Russia); Carbon black: N234 (used in the example data sheet); N375 / N330 / N339 / N347 / N326 and other wear-resistant series can also be used; Multi-walled carbon nanotubes (MWCNTs): Shandong Dazhan Nanomaterials Co., Ltd.; can also be replaced by arrayed carbon nanotubes; Graphene oxide (GO): 2–10 layers; Dihydrazide compound: Sebacic acid dihydrazide (Harbin Quaker New Materials Co., Ltd.); Organosilicon polysulfide: bis[γ-(triethoxysilane)propyl]tetrasulfide (Jiangxi Hongbo New Material Co., Ltd.); Activators: zinc oxide, stearic acid (or zinc stearate); Antioxidants: 4020, 4010, TMQ, RD, etc. (4020 was used in the example); Accelerators: CZ, NS, TMTD, etc. (CZ was used in the examples); Vulcanizing agent: Sulfur (example), or a peroxide system or a composite vulcanizing system may also be used; Tear-resistant resin: CSR200 (can be replaced by polycyclopentadiene resin, C5 / C9 modified resin); Microcrystalline wax: Commercially available microcrystalline wax.

[0038] III. Key Points for Equipment and Critical Process Control 1) Internal mixing equipment: A closed internal mixer (Banbury type or equivalent) is preferred, with adjustable rotor speed, temperature / torque monitoring, and adjustable top plug pressure. 1.6L–5L mixers are suitable for laboratories, while 55L / 75L / 270L mixers are suitable for factories, with the principle of maintaining an equivalent fill factor and shear energy density.

[0039] 2) Open mill equipment: The two-roll open mill is used for thin-passing of rubber material, uniform sheeting after vulcanization, and the roller gap and cooling water temperature are controllable.

[0040] 3) Vulcanization equipment: flat vulcanizing machine, temperature accuracy ±1℃.

[0041] 4) Key Control Points: Premixing stage of nano-reinforced composite materials: avoid excessive temperature rise leading to premature polycondensation / local scorching of silanes; First stage of mixing: Ensure that filler A (especially carbon black / fumed silica) is fully wetted and initially dispersed; Two-stage mixing: Introducing nano-reinforced composite materials in a lower temperature window (135–145℃) to form a stable heterogeneous structure and avoid destroying its enriched network; Vulcanization section: Control the discharge temperature to 105–115℃ to reduce the risk of early vulcanization and ensure processing safety and vulcanization uniformity.

[0042] IV. Preparation methods of nano-reinforced composite materials The following is a directly reproducible preparation process (taking "nano-reinforced composite material A / B" as an example). Its core is: first, rubber B is coated with filler B and undergoes interfacial coupling with organosilicon polysulfide compound, and then dihydrazide compound is introduced to form an interfacial energy dissipation structure.

[0043] Step N1: Equipment preheating and parameter setting Start the internal mixer and set the rotor speed to 30–45 rpm (40 rpm in this example); set the top jack pressure to medium pressure according to the equipment specifications (for laboratory equipment, the default pressure can be used according to the instruction manual; for factory equipment, the equivalent pressure can be controlled at 0.4–0.6 MPa); set the discharge temperature to not exceed 130–145℃ (preferably not exceeding 140℃) to avoid premature and excessive reaction of silane.

[0044] Step N2: Initial mixing of rubber B with filler B and silane Add butadiene rubber (rubber B), filler B (one or more of carbon nanotubes / graphene / carbon black) and organosilicon polysulfide compound in sequence; mix for 25–40 seconds (30 seconds in the example) to allow rubber B to initially wet and coat filler B, while the organosilicon polysulfide compound preferentially accumulates at the interface under high shear.

[0045] Step N3: Introduction of dihydrazide compound and interface construction Add the dihydrazide compound and continue mixing for 1.0–2.5 min (1.5 min in the example). During this stage, through shear-diffusion-interfacial adsorption, the dihydrazide compound forms stable bonds or strong interaction points at the nanofiller / rubber interface, thereby improving the subsequent high-temperature modulus retention and wear resistance.

[0046] Step N4: Debinding and Cooling Once the set time or temperature limit is reached, the glue is removed; the mixture is then passed through a two-roll mill 2–3 times, cooled to room temperature, and left to stand for ≥4 hours (preferably overnight) to stabilize the internal stress, thus obtaining the nano-reinforced composite material.

[0047] V. Mixing Method of Wear-Resistant and High-Temperature Resistant Tread Rubber Composition (a) First stage of mixing (to obtain masterbatch 1) Step M1: Feeding and Initial Mixing Start the internal mixer at 45–55 rpm (50 rpm in this example); add rubber A (NR and / or IR), mix for 10–15 seconds, then add filler A (carbon black and / or silica); then add activator (zinc oxide, stearic acid / zinc stearate), antioxidant, tear-resistant resin, and microcrystalline wax.

[0048] Step M2: Bolt lifting, bolt pressing, and temperature control Continuous mixing for 30–50 seconds (40 seconds in Example); mixing by lifting and pressing the plug for 20–30 seconds (25 seconds in Example), repeating 1–2 times to ensure that filler A is fully dispersed; when the rubber temperature rises to 150–165°C (160°C in Example), the rubber is discharged to obtain masterbatch 1.

[0049] Note: The purpose of the first stage of mixing is to complete the dispersion and structure establishment of the "conventional reinforcing system," reserving interface and distribution space for the subsequent second stage of introducing nano-reinforced composite materials. Insufficient dispersion in the first stage will lead to fluctuations in the final wear resistance and high-temperature modulus; if the temperature is too high, it may cause scorching or loss of antioxidants.

[0050] (ii) Two-stage mixing (to obtain masterbatch 2) Step M3: Low-temperature introduction of nano-reinforced composite materials Start the internal mixer at a speed of 25–35 rpm (30 rpm in the example); add masterbatch 1 and plasticize for 15–20 s, then add nano-reinforced composite material (15–45 parts, 31 parts in the example); mix for 30–50 s (35 s in the example), then mix by lifting and pressing the plug for 20–30 s (20 s in the example), and discharge the glue at a temperature of 135–145 ℃ (140 ℃ in the example) to obtain masterbatch 2.

[0051] Note: Two-stage mixing is the key step in this invention to form the "heterogeneous distribution of fillers". By introducing nano-reinforced composite materials at a lower temperature window, it is possible to promote their uniform dispersion in the masterbatch 1 as an enriched phase, while avoiding high-temperature shear damage to their internal nano-network structure, thereby achieving a synergistic improvement in high-temperature modulus and wear resistance.

[0052] (III) Vulcanization stage (to obtain the final rubber compound) Step M4: Low-Temperature Sulfurization and Safety Control Start the internal mixer at a speed of 25–35 rpm (25 rpm in the example); add masterbatch 2 and vulcanizing agent / accelerator system (sulfur + CZ in the example), mix for 30–50 s (35 s in the example), then mix for 20–30 s with the plug lifted and pressed (30 s in the example); control the discharge temperature at 105–115℃ (112℃ in the example) to discharge the rubber, and obtain a wear-resistant and high-temperature resistant tread rubber composition.

[0053] VI. Examples and Comparative Examples To verify that the present invention can be implemented within the scope of the claims and achieve essentially the same effect, and to demonstrate the technical contribution of "pre-fabricating nano-reinforced composite materials and introducing heterogeneous distribution in two-stage mixing", the following embodiments and comparative examples are designed.

[0054] 1. Explanation of Formulation Design Principles Examples: All satisfy the scope of claims 1–8 regarding rubber A, filler A, activator, vulcanizing agent, antioxidant, nano-reinforced composite material and its internal composition.

[0055] Comparative examples: Controls were established by eliminating or weakening key features (such as not prefabricating nano-reinforced composite materials, or lacking dihydrazide compounds / silane coupling, etc.), while keeping other conditions as consistent as possible, in order to demonstrate the source of the technical effect of the present invention.

[0056] 2. Examples 1–2 and Comparative Examples 1–2

[0057] The formulations of Examples 1–2 and Comparative Examples 1–2 are shown in Table 1.

[0058] Table 1 Example 1 Example 2 Comparative Example 1 Comparative Example 2 Natural rubber*1 75 75 75 75 N234 50 50 50 50 Zinc oxide 3.0 3.0 3.0 3.0 stearic acid 2.5 2.5 2.5 2.5 sulfur 1.3 1.3 1.3 1.3 Vulcanization accelerator CZ 1.0 1.0 1.0 1.0 Anti-aging agent 4020 2.5 2.5 2.5 2.5 CSR200 tear-resistant resin 1 1 1 1 Microcrystalline wax 1 1 1 1 Butadiene rubber *2 / / 25 25 N234 / / 3.5 2.5 Multi-walled carbon nanotubes *3 / / / 1 Sebacic acid dihydrazide*4 / / 1 1 Organosilicon polysulfides*5 / / 1.5 1.5 Nano-reinforced composite material A 31.0 / / / Nano-reinforced composite material B / 31.0 / / Note: The "nano-reinforced composite material A / B" shown in Examples 1 and 2 was pre-prepared according to Table 2 and added during the two-stage mixing process; Comparative Examples 1 and 2 did not pre-prepare the nano-reinforced composite material, but instead directly added rubber B, filler B, diacylhydrazine compound and silane during the two-stage mixing process (equal total amount control).

[0059] The formulations of nano-reinforced composite materials are shown in Table 2.

[0060] Table 2 Nano-reinforced composite material A Nano-reinforced composite material B Butadiene rubber *2 25 25 Packing material BN234 3.5 2.5 Filler B: Multi-walled carbon nanotubes *3 / 1 Sebacic acid dihydrazide compound *4 1 1 Organosilicon polysulfide compounds*5 1.5 1.5

[0061] The preparation method of nano-reinforced composite materials is as follows: Start the internal mixer, set the speed to 40 rpm, add cis-butadiene rubber, filler B and organosilicon polysulfide compound, mix for 30 seconds, add dihydrazide compound, continue mixing for 1.5 minutes, discharge the glue, and obtain nano-reinforced composite material.

[0062] The preparation method of the example is as follows: 1) First stage mixing: Start the internal mixer, set the speed to 50 rpm, add natural rubber, filler A, activator, antioxidant, tear-resistant resin and microcrystalline wax, mix for 40 seconds, then mix for 25 seconds with the plug lifted and pressed, and then mix until 160℃ to discharge the glue to obtain masterbatch 1. 2) Two-stage mixing: Start the internal mixer, set the speed to 30 rpm, add masterbatch 1 and nano-reinforced composite material, mix for 35 seconds, then mix for 20 seconds with the plunger lifted and pressed, and finally mix at 140°C to discharge the glue to obtain masterbatch 2. 3) Vulcanization: Start the internal mixer, set the speed to 25 rpm, add masterbatch 2 and vulcanizing agent, mix for 35 seconds, then mix for 30 seconds with the plunger lifted and pressed, and finally mix until 112°C to discharge the rubber, thus obtaining a wear-resistant and high-temperature resistant rubber composition.

[0063] The preparation method for the comparative example is as follows: 1) First stage mixing: Start the internal mixer, set the speed to 50 rpm, add all materials except vulcanizing agent, dihydrazide compound and organic vulcanizing agent, mix for 40 seconds, mix for 25 seconds with lifting and pressing the plug, mix with lifting and pressing the plug until 160℃ to discharge the glue, and obtain masterbatch 1. 2) Two-stage mixing: Start the internal mixer, set the speed to 30 rpm, add masterbatch 1, dihydrazide compound and organic vulcanizing agent, mix for 35 seconds, then mix for 20 seconds with the plunger lifted and pressed, and then mix until 140℃ to discharge the glue to obtain masterbatch 2. 3) Vulcanization: Start the internal mixer, set the speed to 25 rpm, add masterbatch 2 and vulcanizing agent, mix for 35 seconds, then mix for 30 seconds with the plunger lifted and pressed, and finally mix until 112°C to discharge the rubber composition.

[0064] VII. Vulcanization, Sample Preparation and Testing Methods 1. Vulcanization conditions Based on the measurements obtained using a rotorless vulcanizer (MDR) Determine the vulcanization time; if not tested separately, use the standard tread rubber setting: 160℃, 15 minutes (example), and adjust accordingly based on actual conditions. Fine-tuning.

[0065] Flat vulcanizing machine temperature: 160±1℃; pressure: 10–15MPa; mold thickness: 2mm (for tensile test pieces) / 6mm (for abrasion test pieces).

[0066] 2. Mechanical properties Tensile properties (TB, EB%, M50, M300): Refer to GB / T528 or ISO37, dumbbell-shaped specimen, tensile speed 500 mm / min; 3. High-temperature tensile testing: The specimens were preheated in a 100℃ constant temperature chamber for 15 minutes before tensile testing. 4. Dynamic energy storage modulus The dynamic mechanical analyzer (DMA) was used in tensile or shear mode at a frequency of 10 Hz and a dynamic strain of 0.1% (or the linear viscoelastic region condition recommended by the equipment). The temperature was controlled at 60 ℃ and stabilized for 5 minutes before taking the reading.

[0067] 5. Abrasion resistance (Akron abrasion) Refer to GB / T1689 or ASTM D1630, and test according to the specified load and stroke. The results are expressed as wear volume (or wear amount). Table 3 gives the Akron wear values ​​(the smaller the value, the better the wear resistance).

[0068] The rubber compositions obtained in the examples and comparative examples were subjected to performance tests, and the test results are shown in Table 3.

[0069] Table 3 project Example 1 Example 2 Comparative Example 1 Comparative Example 2 M50 1.8 2.1 1.6 1.9 M300 19 20.5 18.5 19.6 TB 27 28 26.7 25.8 EB% 530 524 536 528 High temperature 100℃, M300 12.3 12.8 9.5 10.1 High temperature 100℃, TB 20.5 21.4 18.3 19.1 E’(60℃) 7.4 7.8 6.2 6.7 Akron wear 0.105 0.085 0.178 0.162 As can be seen from Examples 1 and 2 and Comparative Examples 1 and 2 above, the use of nano-reinforced composite materials can significantly improve the high-temperature resistance of the tread rubber composition. Under high-temperature tensile conditions at 100°C, M300 increases by 29.4% and 26.7% respectively; E' at 60°C increases by 19.3% and 16.4% respectively; and abrasion resistance increases by 41% and 47.5% respectively. It is evident that the tread rubber composition prepared by this invention possesses abrasion resistance and high-temperature resistance.

[0070] VIII. Tire Manufacturing and Application The wear-resistant and high-temperature resistant tread rubber composition of the present invention can be used to prepare wear-resistant and high-temperature resistant tires according to conventional tire manufacturing processes. 1) The final rubber compound is calendered / extruded to form tread strips; 2) It is bonded to the body, belt layer and other semi-finished parts on the molding machine; 3) Mix the tire specifications and rubber compound in the vulcanizing machine. Determine the vulcanization regime (e.g., adjust within the range of 160–170℃, 10–15MPa, and 12–18min); 4) A wear-resistant and high-temperature resistant tire with the rubber compound of the present invention is obtained, which is suitable for high-temperature working conditions or heavy-load / long-distance driving and other application scenarios with higher requirements for wear resistance and high-temperature modulus maintenance.

[0071] In summary, this invention achieves the following through: 1) Pre-preparation of a nano-reinforced composite material containing rubber B, filler B, organosilicon polysulfide compound and diacylhydrazine compound; 2) It is introduced into the low temperature window of the second stage of mixing, so that it is distributed in the tread masterbatch in the form of enriched phase, forming a stable heterogeneous distribution of fillers and a reinforced interface. This allows for a synergistic improvement in modulus retention, wear resistance, and heat resistance of the tread compound in the 60–100℃ driving temperature range without sacrificing conventional processability.

[0072] The foregoing description of embodiments of the present invention, through which those skilled in the art are able to implement or use the present invention, will be readily apparent to those skilled in the art. Various modifications to these embodiments will be readily apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novelty disclosed herein.

Claims

1. A wear-resistant and high-temperature resistant tire tread rubber composition, characterized in that, The rubber composition is prepared by mixing raw materials comprising the following components in parts by weight: Rubber A 65-80 parts, Packing material A: 40-60 parts Activator 3.0-6.0 parts, 2.0-4.0 parts of vulcanizing agent. Anti-aging agent 2.0-5.0 parts, 15-45 parts of nano-reinforced composite material The rubber is natural rubber and / or synthetic isoprene rubber, and filler A is carbon black and / or silica. The nano-reinforced composite material is prepared by mixing raw materials comprising the following components in parts by weight: Rubber B 20-40 parts, Packing material B: 1.0-10 parts Organosilicon polysulfide compounds, 1.0-4.0 parts. 0.4-2.0 parts of diacylhydrazide compound; Rubber B is selected from butadiene rubber; the total weight of rubber A and rubber B is 100 parts by weight, and the filler B is one or more of carbon nanotubes, graphene, and carbon black.

2. The wear-resistant and high-temperature resistant tread rubber composition according to claim 1, characterized in that, The rubber composition is prepared by mixing raw materials comprising the following components in parts by weight: Rubber A 70-80 parts, Packing material A, 50-60 parts. Activator 4.0-6.0 parts, 2.0-3.0 parts of vulcanizing agent, Anti-aging agent 2.0-4.0 parts, Nano-reinforced composite materials 25-40, The nano-reinforced composite material is prepared by mixing raw materials comprising the following components in parts by weight: Rubber B 20-35 parts, Packing material B: 2.0-5.0 parts. 1.0-2.5 parts of organosilicon polysulfide compounds, 0.5-1.5 parts of dihydrazide compound.

3. The wear-resistant and high-temperature resistant tread rubber composition according to claim 1 or 2, characterized in that, The carbon black in filler A is one or two of N375, N330, N339, N347, and N326; And / or, the carbon nanotubes in filler B are arrayed, the carbon black is N375, N330, N339, N347 or N326, and the graphene is 2-10 layers of graphene oxide.

4. The wear-resistant and high-temperature resistant tread rubber composition according to claim 1 or 2, characterized in that, The organosilicon polysulfide is selected from one or more of γ-mercaptopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, bis(3-mercaptopropyl)tetrasulfide, bis(3-mercaptopropyl)disulfide, mercaptoethyltriethoxysilane, mercaptopropylsiloxane copolymer, methylthiol silane, dimercaptoethylsilane, tetra(mercaptopropyl)silane, and bis(γ-triethoxysilylpropyl)sulfide.

5. The wear-resistant and high-temperature resistant tread rubber composition according to claim 1 or 2, characterized in that, The activator is selected from one or more of zinc oxide, stearic acid, and zinc stearate; And / or, the antioxidant is selected from one or more of antioxidant 4010, antioxidant 4020, antioxidant RD, 2-mercaptobenzothiazole, and antioxidant TMQ; And / or, the vulcanizing agent is selected from one or more of sulfur, dicumyl peroxide, vulcanization accelerator NS, vulcanization accelerator CZ, and tetramethylthiuram disulfide.

6. The wear-resistant and high-temperature resistant tread rubber composition according to claim 1 or 2, characterized in that, The raw materials for this rubber composition also include 0.5-1.5 parts of tear-resistant resin and 0.5-2 parts of microcrystalline wax.

7. The wear-resistant and high-temperature resistant tread rubber composition according to claim 6, characterized in that, The tear-resistant resin is one or more of polycyclopentadiene resin, C5 modified resin, and C9 modified resin.

8. The wear-resistant and high-temperature resistant tread rubber composition according to claim 1 or 2, characterized in that, The preparation method of the nano-reinforced wear-resistant composite material includes the following steps: start the internal mixer, set the speed to 30-45 rpm, add natural rubber, filler and organosilicon polysulfide, mix for 25-40 seconds, add dihydrazide compound, continue mixing for 1-2.5 minutes, discharge the glue, and obtain the nano-reinforced composite material.

9. A method for mixing a wear-resistant and high-temperature resistant tread rubber composition according to any one of claims 1-8, characterized in that, Includes the following steps: 1) First stage mixing: Start the internal mixer, set the speed to 45-55 rpm, add rubber, filler A, activator, antioxidant, tear-resistant resin and microcrystalline wax, mix for 30-50 seconds, then mix for 20-30 seconds with the plunger lifted and pressed, and then mix until 150-165℃ to discharge the glue to obtain masterbatch 1. 2) Two-stage mixing: Start the internal mixer, set the speed to 25-35 rpm, add masterbatch 1 and nano-reinforced composite material, mix for 30-50 seconds, then mix for 20-30 seconds with the plug lifted and pressed, and finally mix at 135-145℃ to discharge the glue to obtain masterbatch 2. 3) Vulcanization: Start the internal mixer, set the speed to 25-35 rpm, add masterbatch 2 and vulcanizing agent, mix for 30-50 seconds, then mix for 20-30 seconds with the plunger lifted and pressed, and finally mix until 105-115℃ to discharge the rubber, thus obtaining a wear-resistant and high-temperature resistant rubber composition.

10. A wear-resistant and high-temperature resistant tire, characterized in that, The tire tread is prepared by vulcanizing the rubber composition obtained according to any one of claims 1-8.

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