Tread rubber composition, preparation method thereof and tire for new energy automobile

Abstract

The invention discloses a tread rubber composition, a preparation method thereof and a tire for a new energy automobile, and belongs to the field of tire rubber compositions. The technical scheme comprises a rubber compound; the rubber compound comprises nitrile rubber, white carbon black, a silane coupling agent and MXene; and MXene is selected from any one of Ti < 3 > C < 2 >, V < 4 > C < 3 > T < x >, Nb < 2 > T < x > and Ti < 2 > T < x >. The invention is applied to tires for new energy vehicles, solves the problem of static accumulation caused by poor conductivity of existing tires for new energy vehicles, and has the characteristics of good conductivity, excellent road holding force and excellent safety.

Description

Technical Field

[0001] This invention belongs to the field of tire rubber compositions, and particularly relates to a tread rubber composition, its preparation method, and tires for new energy vehicles. Background Technology

[0002] With increasing emphasis on environmental protection and low carbon emissions, new energy vehicles have emerged and developed rapidly in recent years thanks to continuous technological advancements. In China, electric vehicles are the primary form of new energy vehicles; however, due to their weight and high inertia, electric vehicles place higher demands on tire grip.

[0003] Silica has superior wet grip properties compared to carbon black and is more environmentally friendly, leading to its widespread use in new energy vehicles. However, components in new energy vehicles, such as batteries, motors, and control systems, generate electromagnetic and electrostatic fields during operation, which can lead to static electricity accumulation. This makes new energy vehicles more prone to static electricity buildup than conventional gasoline-powered vehicles. Rubber is a poor conductor of electricity and heat, and silica filler is also non-conductive, resulting in tires made with silica filler exhibiting lower conductivity compared to those made with carbon black filler. For new energy vehicles, the inability to conduct static electricity through the tires to the ground poses significant safety hazards, such as fires and explosions.

[0004] Therefore, researchers have been exploring effective methods to improve tire conductivity. Currently, the most researched approach involves adding a conductive rubber strip to the tire. While this method solves the conductivity problem, it increases manufacturing steps and reduces production efficiency. Furthermore, the conductive rubber is generally formulated differently from the tread compound, potentially leading to poor co-curing between the two compounds. Over time, this could result in the conductive rubber separating from the tread compound, and precipitated silica treads exhibit poorer wear resistance compared to carbon black treads. Therefore, solving the conductivity problem in electric vehicle tires and improving their wear resistance and safety performance remains crucial. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the technical problem to be solved by the present invention is the problem of static electricity accumulation caused by poor conductivity in existing tires used for new energy vehicles. The present invention proposes a tread rubber composition with good conductivity, good wear performance and excellent safety, its preparation method and a tire for new energy vehicles.

[0006] To solve the aforementioned technical problem, the technical solution adopted by the present invention is as follows: The present invention provides a tread rubber composition comprising a rubber compound; the rubber compound comprising: nitrile rubber, silica, silane coupling agent, and MXene; MXene is selected from any one of Ti3C2, V4C3Tx, Nb2CTx, and Ti2CTx.

[0007] In some embodiments, the nitrile rubber is a carboxylated nitrile rubber.

[0008] In some embodiments, the amount of MXene used is not less than 1.5% of the amount of nitrile rubber used.

[0009] In some embodiments, the amount of MXene used is 5-6% of the amount of nitrile rubber used.

[0010] In some embodiments, the tread rubber composition further includes: styrene-butadiene rubber, cis-butadiene rubber, and an activator; the activator includes zinc oxide and stearic acid; or the activator includes zinc peroxide and stearic acid; or the activator includes zinc oxide, zinc peroxide, and stearic acid.

[0011] In some embodiments, the tread rubber composition further includes: filler, silane coupling agent, sulfur, accelerator, scorch inhibitor, and antioxidant.

[0012] In some embodiments, the rubber compound comprises, by weight, 100 parts of nitrile rubber, 40-60 parts of silica, 3-5 parts of silane coupling agent, and 3-8 parts of MXene.

[0013] In some embodiments, the tread rubber composition comprises, by weight: 50-70 parts of styrene-butadiene rubber, 10-30 parts of butadiene rubber, 15-35 parts of rubber compound, 70-80 parts of filler, 4-8 parts of silane coupling agent, 3-7 parts of activator, 2-4 parts of sulfur, 1-3 parts of accelerator, 0.1-0.3 parts of scorch inhibitor, and 3-5 parts of antioxidant.

[0014] Another aspect of the present invention provides a method for preparing a tread rubber composition according to any of the above technical solutions, comprising: first adding nitrile rubber and MXene, pressing with a roller for 40s or raising the temperature to 115°C, lifting the roller, cleaning, adding silica and silane coupling agent, pressing with a roller for 25s or raising the temperature to 145°C, lifting the roller, cleaning, mixing at a constant temperature of 145°C for 60s, discharging the rubber, sheeting, cooling, and obtaining a rubber composite.

[0015] In some embodiments, the mixture further includes: masterbatch mixing and final rubber mixing; When the surfactant includes zinc oxide and stearic acid: The masterbatch mixing process includes: adding styrene-butadiene rubber, butadiene rubber, rubber compound, silica, silane coupling agent, activator, 4020 and protective wax, pressing with a roller for 30 seconds or raising the temperature to 105°C, lifting the roller, cleaning, pressing with a roller for 30 seconds or raising the temperature to 135°C, lifting the roller, cleaning, pressing with a roller for 40 seconds or raising the temperature to 145°C, lifting the roller, cleaning, mixing at a constant temperature of 145°C for 180 seconds, discharging the glue, sheeting, cooling, and obtaining the masterbatch. The final rubber compounding process includes: adding masterbatch, sulfur, CZ, and CTP; pressing with a roller for 30 seconds or raising the temperature to 85°C; lifting the roller; cleaning; pressing with a roller for 30 seconds or raising the temperature to 105°C; lifting the roller; cleaning; pressing with a roller for 30 seconds or raising the temperature to 110°C; discharging the rubber; cutting the sheet; and cooling. When the surfactant includes zinc peroxide and stearic acid; or when the surfactant includes zinc oxide, zinc peroxide and stearic acid: The masterbatch mixing process includes: adding styrene-butadiene rubber, butadiene rubber, rubber compound, silica, silane coupling agent, 4020 and protective wax, pressing with a roller for 30 seconds or raising the temperature to 105°C, lifting the roller, cleaning, pressing with a roller for 30 seconds or raising the temperature to 135°C, lifting the roller, cleaning, pressing with a roller for 40 seconds or raising the temperature to 145°C, lifting the roller, cleaning, mixing at a constant temperature of 145°C for 180 seconds, discharging the rubber, sheeting, cooling, and obtaining the masterbatch. The final rubber compounding process includes: adding masterbatch, activator, sulfur, CZ, and CTP; pressing with a roller for 30 seconds or raising the temperature to 85°C; lifting the roller; cleaning; pressing with a roller for 30 seconds or raising the temperature to 105°C; lifting the roller; cleaning; pressing with a roller for 30 seconds or raising the temperature to 110°C; discharging the rubber; sheeting; and cooling.

[0016] The present invention also provides a tire for new energy vehicles, wherein the tread of the tire for new energy vehicles is made of a tread rubber composition of any of the above-mentioned technical solutions.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides a tread rubber composition using a rubber compound, specifically comprising nitrile rubber, silica, a silane coupling agent, and MXene. MXene contains polar groups, and when mixed with nitrile rubber, which also has polar functional groups, MXene can be fully dispersed in the nitrile rubber, forming a good conductor together. This composition is then used as a rubber compound in conjunction with other rubbers to produce a rubber composition with excellent antistatic properties. Furthermore, the addition of some nitrile rubber enhances the tire's grip performance, thus simultaneously addressing two major safety issues of new energy vehicles. Detailed Implementation

[0018] The technical solutions in specific embodiments of the present invention will be described in detail and completely below. Obviously, the described embodiments are only some specific implementations of the overall technical solution of the present invention, and not all implementations. Based on the overall concept of the present invention, all other embodiments obtained by those skilled in the art fall within the protection scope of the present invention.

[0019] The present invention provides a tread rubber composition comprising a rubber compound; the rubber compound comprising: nitrile rubber, silica, silane coupling agent, and MXene; MXene is selected from any one of Ti3C2, V4C3Tx, Nb2CTx, and Ti2CTx.

[0020] The aforementioned tread rubber composition uses a rubber compound, which is specified to include nitrile rubber, silica, silane coupling agent, and MXene. MXene is widely used in sensors and batteries, exhibiting excellent electrical and thermal conductivity. Since MXene contains polar groups, mixing it with nitrile rubber, which also has polar functional groups, allows MXene to be fully dispersed in the nitrile rubber, forming a good conductor together. When used as a rubber compound with other rubbers, the resulting rubber composition exhibits good antistatic properties. Furthermore, introducing MXene as a functional filler into the XNBR rubber system enhances the tire's strength and wear resistance due to the stronger interaction between the two components. This simultaneously improves the conductivity, wear resistance, and strength of new energy vehicle tires.

[0021] In addition, the metallic conductivity of Ti3C2 (≈6000S / cm) compensates for the insulation defects of silica. It forms a three-dimensional conductive path through a "lamellae interpenetration" structure (Ti3C2 is inserted into the gaps between silica aggregates) rather than a simple physical blend, thereby realizing a Ti3C2 / silica two-phase conductive network structure.

[0022] In some embodiments, the amount of MXene is not less than 1.5% of the amount of nitrile rubber, that is, the amount of Ti3C2 is ≥1.5phr. A amount less than 1.5phr will result in the inability to penetrate the silica insulation layer.

[0023] In some embodiments, the nitrile rubber is a carboxylated nitrile rubber.

[0024] Carboxylated acrylonitrile butadiene rubber (XNBR) inherently possesses a certain degree of electrical conductivity and polarity, exhibiting good grip. Carboxyl modification increases the polarity of XNBR (=O, = ... OH and F) The binding affinity of Ti3C2. The strong conductivity of Ti3C2 has been confirmed in numerous studies. Due to the addition of XNBR, only a small amount of Ti3C2 is needed to form a conductive network with XNBR, thereby improving the overall conductivity of the tire. Specifically, the carboxyl groups (—COOH) of XNBR form ion channels (—COO) with the —O / —OH groups on the surface of Ti3C2. - •••Ti +Meanwhile, the Ti3C2 sheets provide an electronic conduction path, realizing "ion-electron dual conduction", thereby achieving ion-electron synergistic conduction at the interface.

[0025] In some embodiments, the density of the carboxylated nitrile rubber is 1.5-5.0 mol% to provide sufficient ion pairs. In some embodiments, the carboxyl content in the carboxylated nitrile rubber is 5-15%.

[0026] In some embodiments, the tread rubber composition further includes: styrene-butadiene rubber, cis-butadiene rubber, and an activator; the activator includes zinc oxide and stearic acid; or the activator includes zinc peroxide and stearic acid; or the activator includes zinc oxide, zinc peroxide, and stearic acid.

[0027] Zinc peroxide decomposition provides free Zn 2+ Zinc peroxide is superior to zinc oxide in terms of slow release; its presence can form an ionic crosslinking network (i.e., phase-separated ionic clusters composed of zinc carboxylate) with the carboxyl groups on XNBR, improving the conductivity, abrasion resistance, and mechanical strength of the rubber compound. This characteristic also limits the addition sequence of zinc peroxide to the final rubber compound, and the mixing temperature should not be too high.

[0028] The above technical solution not only solves the problem of static electricity removal in electric vehicles, but also directly makes the entire tire tread conductive, thereby increasing safety. Compared with the production of conductive rubber strips, it simplifies tire components and the production process. The introduction of XNBR and zinc peroxide not only improves tire grip, but also enhances wear resistance and mechanical strength. The ingenious combination of Ti3C2 and XNBR gives the rubber compound good conductivity while further improving tire wear resistance and mechanical strength.

[0029] In some embodiments, the tread rubber composition further includes: filler, silane coupling agent, sulfur, accelerator, scorch inhibitor, and antioxidant. The filler comprises silica (1165MP, 175MP, 200MP); the silane coupling agent is TESPT, Si75, or NXT, a silane coupling agent possessing both organic and inorganic functional groups.

[0030] In some embodiments, the rubber compound comprises, by weight, 100 parts of nitrile rubber, 40-60 parts of silica, 3-5 parts of silane coupling agent, and 3-8 parts of MXene.

[0031] Understandably, the amount of silica can be 42 parts, 44 parts, 46 parts, 48 ​​parts, 50 parts, 52 parts, 54 parts, 56 parts, 58 parts, or any value within the range thereof; the amount of silane coupling agent can be 3.5 parts, 4.0 parts, 4.5 parts, or any value within the range thereof; and the amount of MXene can be 4 parts, 5 parts, 6 parts, 7 parts, or any value within the range thereof.

[0032] The amount of Ti3C2 in the above rubber compound is ≥1.5 phr, which avoids the problem of Ti3C2 not being able to penetrate the silica insulation layer due to the amount of Ti3C2 being less than 1.5 phr.

[0033] In some embodiments, the tread rubber composition, by weight, comprises: 50-70 parts styrene-butadiene rubber, 10-30 parts butadiene rubber, 15-35 parts rubber compound, 70-80 parts filler, 4-8 parts silane coupling agent, 3-7 parts activator, 2-4 parts sulfur, 1-3 parts accelerator, 0.1-0.3 parts scorch inhibitor, and 3-5 parts antioxidant. The raw rubber content of styrene-butadiene rubber and rubber compound is 100 parts.

[0034] Understandably, the amount of styrene-butadiene rubber (SBR) can also be 52 parts, 54 parts, 56 parts, 58 parts, 60 parts, 62 parts, 64 parts, 66 parts, 68 parts, or any value within this range; the amount of butadiene rubber (BR) can also be 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, or any value within this range; the amount of rubber compound can also be 17 parts, 19 parts, 21 parts, 23 parts, 25 parts, 27 parts, 29 parts, 31 parts, 33 parts, or any value within this range; and the amount of filler can also be 72 parts, 74 parts, 76 parts, 7... The dosage of silane coupling agent can be any value within the range of 8 parts; the dosage of silane coupling agent can also be any value within the range of 5 parts, 6 parts, 7 parts; the dosage of activator can also be any value within the range of 4 parts, 5 parts, 6 parts; the dosage of sulfur can also be any value within the range of 2.5 parts, 3.0 parts, 3.5 parts; the dosage of accelerator can also be any value within the range of 1.5 parts, 2.0 parts, 2.5 parts; the dosage of anti-scorching agent can also be any value within the range of 0.2 parts; the dosage of antioxidant can also be any value within the range of 3.5 parts, 4.0 parts, 4.5 parts.

[0035] Another aspect of the present invention provides a method for preparing a tread rubber composition according to any of the above technical solutions, comprising: first adding nitrile rubber and MXene, pressing with a roller for 40s or raising the temperature to 115°C, lifting the roller, cleaning, adding silica and silane coupling agent, pressing with a roller for 25s or raising the temperature to 145°C, lifting the roller, cleaning, mixing at a constant temperature of 145°C for 60s, discharging the rubber, sheeting, cooling, and obtaining a rubber composite.

[0036] The above preparation process specifies the following feeding order: first add XNBR and MXene, allowing them to mix thoroughly for 40 seconds to pre-disperse MXene in XNBR, then add silica and silane coupling agent. This is done to ensure sufficient dispersion of MXene in XNBR, guaranteeing the binding amount of Ti3C2 and XNBR, and better forming an effective conductive network.

[0037] The rubber compound was prepared using an internal mixing process, with the internal mixer maintained at a constant temperature using circulating cooling water at 60°C. Specifically: First, add carboxylated nitrile rubber and Ti3C2 → press for 40 seconds or raise the temperature to 115℃ → lift the roller and clean → then add silica and silane coupling agent → press for 25 seconds or raise the temperature to 145℃ → lift the roller and clean → mix at a constant temperature of 145℃ for 60 seconds to remove the rubber, then use an open mill to sheet the product and cool it.

[0038] In some embodiments, the mixture further includes: masterbatch mixing and final rubber mixing; When the surfactant includes zinc oxide and stearic acid: The masterbatch mixing process includes: adding styrene-butadiene rubber, butadiene rubber, rubber compound, silica, silane coupling agent, activator, 4020 and protective wax, pressing with a roller for 30 seconds or raising the temperature to 105°C, lifting the roller, cleaning, pressing with a roller for 30 seconds or raising the temperature to 135°C, lifting the roller, cleaning, pressing with a roller for 40 seconds or raising the temperature to 145°C, lifting the roller, cleaning, mixing at a constant temperature of 145°C for 180 seconds, discharging the glue, sheeting, cooling, and obtaining the masterbatch. The final rubber compounding process includes: adding masterbatch, sulfur, CZ, and CTP; pressing with a roller for 30 seconds or raising the temperature to 85°C; lifting the roller; cleaning; pressing with a roller for 30 seconds or raising the temperature to 105°C; lifting the roller; cleaning; pressing with a roller for 30 seconds or raising the temperature to 110°C; discharging the rubber; cutting the sheet; and cooling. When the surfactant includes zinc peroxide and stearic acid; or when the surfactant includes zinc oxide, zinc peroxide and stearic acid: The masterbatch mixing process includes: adding styrene-butadiene rubber, butadiene rubber, rubber compound, silica, silane coupling agent, 4020 and protective wax, pressing with a roller for 30 seconds or raising the temperature to 105°C, lifting the roller, cleaning, pressing with a roller for 30 seconds or raising the temperature to 135°C, lifting the roller, cleaning, pressing with a roller for 40 seconds or raising the temperature to 145°C, lifting the roller, cleaning, mixing at a constant temperature of 145°C for 180 seconds, discharging the rubber, sheeting, cooling, and obtaining the masterbatch. The final rubber compounding process includes: adding masterbatch, activator, sulfur, CZ, and CTP; pressing with a roller for 30 seconds or raising the temperature to 85°C; lifting the roller; cleaning; pressing with a roller for 30 seconds or raising the temperature to 105°C; lifting the roller; cleaning; pressing with a roller for 30 seconds or raising the temperature to 110°C; discharging the rubber; sheeting; and cooling.

[0039] Table 1 presents the dynamic performance optimization principle of this invention. As shown in Table 1, this invention achieves the following: 1. Breakthrough in conductivity: Ti3C2 reduces resistivity to 10. 7 Ω•cm (a decrease of 5 orders of magnitude), solving the problem of static electricity buildup in silica tire treads; Key conditions: Ti3C2 ≥ 1.5 phr + XNBR carboxyl groups + zinc peroxide releasing Zn 2+ 2. Rolling resistance-grip balance: Example 1 achieved tanδ=0.096 at 60℃ and tanδ=0.459 at 0℃ (maintained wet grip), which is attributed to the dual regulation effect of thermal conductivity / damping of Ti3C2. 3. Wear and tear improvement The carboxyl groups of XNBR generate stronger interfacial interactions with the functional groups on the Ti3C2 surface, which is the key to the breakthrough in wear resistance.

[0040] Table 1 Principles of Dynamic Performance Optimization

[0041] This invention also provides a tire for new energy vehicles, wherein the tread of the tire is made of a tread rubber composition of any of the above-mentioned technical solutions. Using the above-mentioned tread rubber composition in tires for new energy vehicles effectively solves the problem of static electricity accumulation caused by poor conductivity in existing tires for new energy vehicles, while also exhibiting good conductivity, excellent grip, and superior safety.

[0042] To provide a clearer and more detailed description of the tread rubber composition, its preparation method, and tires for new energy vehicles provided in the embodiments of the present invention, specific embodiments will be described below.

[0043] The specific information of the raw materials used in the examples and comparative examples is as follows: Styrene-butadiene rubber 2055, Dushanzi Petrochemical; XNBR, Nanjing Shengdong Chemical Co., Ltd.; 1165MP Solverodia; Ti3C2, Bohuas Nanotechnology Co., Ltd.; Zinc peroxide, Wuhan Jixin Yibang Biotechnology Co., Ltd.; and the remaining products are all commercially available.

[0044] The amount of raw materials used is shown in Table 2.

[0045] Table 2. Raw material consumption of the examples and comparative examples

[0046] In Table 1, BR9000 is cis-butadiene rubber, NBR is nitrile rubber, and XNBR is carboxylated nitrile rubber.

[0047] Example 1 (1) The rubber compound is mixed using an internal mixing process, and the internal mixer is kept at a constant temperature using 60°C cooling circulating water.

[0048] First, add carboxylated nitrile rubber and Ti3C2 → press for 40 seconds or raise the temperature to 115℃ → lift the roller and clean → then add silica and silane coupling agent → press for 30 seconds or raise the temperature to 145℃ → lift the roller and clean → mix at a constant temperature of 145℃ for 60 seconds to remove the rubber, then use an open mill to sheet the rubber compound and cool it.

[0049] (2) The rubber compound is mixed using an internal mixing process, and the internal mixer is kept at a constant temperature using 60°C cooling circulating water.

[0050] The mixing process is carried out in two stages.

[0051] The masterbatch mixing process is as follows: Add styrene-butadiene rubber, butadiene rubber, rubber compound, silica, silane coupling agent, 4020 and protective wax to the internal mixer → press the roller for 30 seconds or raise the temperature to 105℃ → lift the roller and clean → press the roller for 30 seconds or raise the temperature to 135℃ → lift the roller and clean → press the roller for 40 seconds or raise the temperature to 145℃ → lift the roller and clean → mix at a constant temperature of 145℃ for 180 seconds and discharge the rubber. Then, use an open mill to sheet the rubber and cool it.

[0052] The rotor speed is kept constant at 60 r / min during final rubber mixing. The mixing process is as follows: add masterbatch, zinc oxide, zinc peroxide, stearic acid, sulfur, CZ, CTP → press for 30s or raise the temperature to 85℃ → lift the roller, clean → press for 30s or raise the temperature to 105℃ → lift the roller, clean → press for 30s or raise the temperature to 110℃, discharge the rubber, and use an open mill to sheet and cool.

[0053] (3) The samples were vulcanized using a flat vulcanizing machine. Vulcanization conditions: temperature 161℃, pressure 10MPa, time: depending on the thickness of the sample.

[0054] Example 2 (1) The rubber compound is mixed using an internal mixing process, and the internal mixer is kept at a constant temperature using 60°C cooling circulating water.

[0055] First, add carboxylated nitrile rubber and Ti3C2 → press for 40 seconds or raise the temperature to 115℃ → lift the roller and clean → then add silica and silane coupling agent → press for 30 seconds or raise the temperature to 145℃ → lift the roller and clean → mix at a constant temperature of 145℃ for 60 seconds to remove the rubber, then use an open mill to sheet the rubber compound and cool it.

[0056] (2) The rubber compound is mixed using an internal mixing process, and the internal mixer is kept at a constant temperature using 60°C cooling circulating water.

[0057] The mixing process is carried out in two stages.

[0058] The masterbatch mixing process is as follows: Add styrene-butadiene rubber, butadiene rubber, rubber compound, silica, silane coupling agent, zinc oxide, stearic acid, 4020 and protective wax to the internal mixer → press the roller for 30s or raise the temperature to 105℃ → lift the roller and clean → press the roller for 30s or raise the temperature to 135℃ → lift the roller and clean → press the roller for 40s or raise the temperature to 145℃ → lift the roller and clean → mix at a constant temperature of 145℃ for 180s and discharge the rubber. Then, use an open mill to sheet the rubber and cool it.

[0059] The rotor speed is kept constant at 60 r / min during final rubber mixing. The mixing process is as follows: add masterbatch, sulfur, CZ, CTP → press for 30s or raise the temperature to 85℃ → lift the roller and clean → press for 30s or raise the temperature to 105℃ → lift the roller and clean → press for 30s or raise the temperature to 110℃, discharge the rubber, and use an open mill to sheet and cool.

[0060] (3) The samples were vulcanized using a flat vulcanizing machine. Vulcanization conditions: temperature 161℃, pressure 10MPa, time: depending on the thickness of the sample.

[0061] Reference ratio 1 The mixing process is as follows: the rubber compound is mixed using an internal mixer, which is kept at a constant temperature using 60°C cooling circulating water. The mixing is carried out in two stages.

[0062] The masterbatch mixing process is as follows: Add styrene-butadiene rubber, butadiene rubber, silica, silane coupling agent, zinc oxide, stearic acid, 4020 and protective wax to the internal mixer → press the roller for 30 seconds or raise the temperature to 105℃ → lift the roller and clean → press the roller for 30 seconds or raise the temperature to 135℃ → lift the roller and clean → press the roller for 40 seconds or raise the temperature to 145℃ → lift the roller and clean → mix at a constant temperature of 145℃ for 180 seconds and discharge the rubber. Then, use an open mill to sheet the rubber and cool it.

[0063] The rotor speed is kept constant at 60 r / min during final rubber mixing. The mixing process is as follows: add masterbatch, sulfur, CZ, CTP → press for 30s or raise the temperature to 85℃ → lift the roller and clean → press for 30s or raise the temperature to 105℃ → lift the roller and clean → press for 30s or raise the temperature to 110℃, discharge the rubber, and use an open mill to sheet and cool.

[0064] Comparative Example 1 Compared to the reference ratio, the 20 phr SSBR was replaced with nitrile rubber (NBR).

[0065] Comparative Example 2 Compared to the reference ratio, the 20 phr SSBR was replaced with a composite of nitrile butadiene rubber (NBR) and Ti3C2, where Ti3C2 constitutes 2% of the NBR. Specifically: The mixing process is as follows: the rubber compound is mixed using an internal mixer, which is kept at a constant temperature using 60°C cooling circulating water. The mixing is carried out in two stages.

[0066] The masterbatch mixing process is as follows: Add styrene-butadiene rubber, butadiene rubber, NBR, Ti3C2, silica, silane coupling agent, zinc oxide, stearic acid, 4020 and protective wax to the internal mixer → press the roller for 30s or raise the temperature to 105℃ → lift the roller and clean → press the roller for 30s or raise the temperature to 135℃ → lift the roller and clean → press the roller for 40s or raise the temperature to 145℃ → lift the roller and clean → mix at a constant temperature of 145℃ for 180s and discharge the rubber. Then, use an open mill to sheet the rubber and cool it.

[0067] The rotor speed is kept constant at 60 r / min during final rubber mixing. The mixing process is as follows: add masterbatch, sulfur, CZ, CTP → press for 30s or raise the temperature to 85℃ → lift the roller and clean → press for 30s or raise the temperature to 105℃ → lift the roller and clean → press for 30s or raise the temperature to 110℃, discharge the rubber, and use an open mill to sheet and cool.

[0068] Comparative Example 3 Compared to the reference ratio, the 20 phr SSBR was replaced with a composite of carboxyl-modified nitrile butadiene rubber (XNBR) and Ti3C2, where Ti3C2 constitutes 2% of XNBR. Specifically: The mixing process is as follows: the rubber compound is mixed using an internal mixer, which is kept at a constant temperature using 60°C cooling circulating water. The mixing is carried out in two stages.

[0069] The masterbatch mixing process is as follows: Add styrene-butadiene rubber, butadiene rubber, XNBR, Ti3C2, silica, silane coupling agent, zinc oxide, stearic acid, 4020 and protective wax to the internal mixer → press the roller for 30s or raise the temperature to 105℃ → lift the roller and clean → press the roller for 30s or raise the temperature to 135℃ → lift the roller and clean → press the roller for 40s or raise the temperature to 145℃ → lift the roller and clean → mix at a constant temperature of 145℃ for 180s and discharge the rubber. Then, use an open mill to sheet the rubber and cool it.

[0070] The rotor speed is kept constant at 60 r / min during final rubber mixing. The mixing process is as follows: add masterbatch, sulfur, CZ, CTP → press for 30s or raise the temperature to 85℃ → lift the roller and clean → press for 30s or raise the temperature to 105℃ → lift the roller and clean → press for 30s or raise the temperature to 110℃, discharge the rubber, and use an open mill to sheet and cool.

[0071] Comparative Example 4 Compared to the reference ratio, the 20 phr SSBR was replaced with a composite of carboxyl-modified nitrile butadiene rubber XNBR and Ti3C2; where Ti3C2 was 2% of XNBR, zinc oxide was replaced with zinc peroxide, and zinc peroxide and stearic acid were added to the final rubber compound. Specifically: The mixing process is as follows: (1) The rubber compound is mixed using an internal mixing process, and the internal mixer is kept at a constant temperature using 60°C cooling circulating water.

[0072] First, add carboxylated nitrile rubber and Ti3C2 → press for 40 seconds or raise the temperature to 115℃ → lift the roller and clean → then add silica and silane coupling agent → press for 30 seconds or raise the temperature to 145℃ → lift the roller and clean → mix at a constant temperature of 145℃ for 60 seconds to remove the rubber, then use an open mill to sheet the rubber compound and cool it.

[0073] (2) The rubber compound is mixed using an internal mixing process, and the internal mixer is kept at a constant temperature using 60°C cooling circulating water.

[0074] The mixing process is carried out in two stages.

[0075] The masterbatch mixing process is as follows: Add styrene-butadiene rubber, butadiene rubber, rubber compound, silica, silane coupling agent, 4020 and protective wax to the internal mixer → press the roller for 30 seconds or raise the temperature to 115℃ → lift the roller and clean → press the roller for 30 seconds or raise the temperature to 135℃ → lift the roller and clean → press the roller for 40 seconds or raise the temperature to 145℃ → lift the roller and clean → mix at a constant temperature of 145℃ for 180 seconds and discharge the rubber. Then, use an open mill to sheet the rubber and cool it.

[0076] The rotor speed is kept constant at 60 r / min during final rubber mixing. The mixing process is as follows: add masterbatch, zinc peroxide, stearic acid, sulfur, CZ, CTP → press for 30s or raise the temperature to 85℃ → lift the roller and clean → press for 30s or raise the temperature to 105℃ → lift the roller and clean → press for 30s or raise the temperature to 110℃, discharge the rubber, and use an open mill to sheet and cool.

[0077] Comparative Example 5 Compared to the control example, the 20 phr SSBR was replaced with a composite of carboxyl-modified nitrile rubber XNBR and Ti3C2, where Ti3C2 was 8% by mass of XNBR, and the mixing process was the same as that of control example 3.

[0078] Performance testing The products obtained from the examples, comparative examples, and reference examples were tested according to the test methods in Table 3. The test results are shown in Table 4.

[0079] Table 3. Equipment and National Standards Corresponding to Test Methods

[0080] Table 4 Processing performance data and physical property data

[0081] As shown in Table 4: 1. Electrical conductivity: The formation of the filler network and the percolation threshold The resistivity of the insulator (≥10) is compared to that of the reference insulator. 12 Ω•cm) decreased to 10 of Comparative Example 5 7 Ω•cm. As a two-dimensional conductive sheet, Ti3C2 needs to form a through-network in the rubber matrix to conduct electricity.

[0082] From Comparative Example 3 (2%, 10) 10 Ω•cm) to Examples 1 and 2 (5-6%, 10) 7The resistivity decreased by 3 orders of magnitude (Ω•cm), indicating that the content of 5-6% has approached or reached the percolation threshold, and the network is initially perfected.

[0083] Comparative Example 5 (8%, 10) 7 The resistivity (Ω•cm) was only 0.5 orders of magnitude lower than that of Example 2, but at the cost of a significant increase in processing viscosity (Mounney viscosity 75.6) and a shorter scorch time. This indicates that 5-6% is the optimal range for conductivity addition in terms of cost-effectiveness and processability. Further increases in content result in a decreasing conductivity effect, but at the cost of significant compromises in processing.

[0084] 2. Mechanical properties: Enhanced by both interfacial interaction and cross-linking density Tensile strength, tear strength, and 300% elongation stress all steadily increased with increasing Ti3C2 content and the matrix was changed to XNBR. Interface reinforcement effect: Comparing Comparative Example 2 (NBR+2%) with Comparative Example 3 (XNBR+2%), it was found that, at the same filler content, the latter had higher strength in all aspects. This is because the -COOH carboxyl groups on the XNBR molecular chain can form stronger hydrogen bonds or chemical interactions with the -OH functional groups on the Ti3C2 sheet surface, significantly improving the stress transfer efficiency between the filler and the matrix.

[0085] Filler network reinforcement: As a rigid two-dimensional nanosheet, Ti3C2 has extremely high modulus and strength. The network it forms can effectively restrict molecular chain slippage and improve modulus (stress at a given elongation) and hardness.

[0086] Contribution of the vulcanization system: Example 1 uses a combination of zinc oxide (4 parts) and zinc peroxide (1 part), which may form a richer and more stable ionic crosslinking and covalent crosslinking network. In synergy with the Ti3C2 network, it makes the tensile strength (18.8 MPa) at 5% content close to the level of Comparative Example 5 (8%, 18.6 MPa).

[0087] 3. Dynamic Mechanical Properties (DMA) and Abrasion Resistance: Manifestations of Wear and Interfacial Bonding Tg increased from -15.2℃ in Reference Example 1 to -12.8℃ in Comparative Example 5.

[0088] Changes in tanδ value: The tanδ value at 0℃ (characterizing the grip potential of wet and slippery road surfaces) generally decreases with the increase of filler material; the tanδ value at 60℃ (characterizing rolling resistance) also decreases synchronously.

[0089] DIN wear was significantly improved: from 90 in comparative example 1 to 109 in comparative example 5.

[0090] The increase in Tg indicates that the addition of Ti3C2 restricts the movement of rubber molecular chain segments, which is a typical manifestation of the "constraint layer" effect of nanofillers. The overall decrease in tanδ indicates that the reinforcing effect of the filler network is dominant, and the obstruction of molecular chain movement leads to reduced energy dissipation. This suggests that the product may have lower rolling resistance (energy saving), but low-temperature grip may be slightly sacrificed, which needs to be balanced in practical applications.

[0091] The significant improvement in wear resistance (DIN wear) is the result of the combined effects of high modulus (high elongation), high strength, and good interfacial bonding. The Ti3C2 lamellars have high hardness, while the strong interfacial bonding prevents the filler from being "pulled out" during wear. The wear values ​​of Examples 1 and 2 are far superior to those of the low-content group, demonstrating the importance of sufficient filler content for forming an effective wear-resistant protective network.

[0092] 4. Processing Performance: Mooney viscosity continued to increase, while scorch time (T5) and positive vulcanization time (T90) were generally shortened. The increase in viscosity was due to the increased flow resistance caused by the increased filler content. The accelerated vulcanization speed may be due to the slight promotion of vulcanization by the functional groups on the Ti3C2 surface, and the filler network facilitating heat conduction. Comparative Example 4, due to the use of zinc peroxide, resulted in a significant reduction in scorch time and vulcanization speed, posing a processing safety issue. In Example 1, at a high content of 5%, the addition of one part of zinc peroxide improved the formation of an ionic crosslinking network of carboxyl groups on XNBR (i.e., phase-separated ionic clusters composed of zinc carboxylate), thereby improving the conductivity and interfacial bonding of the rubber composite. Furthermore, by increasing the anti-scorch agent CTP from 0.2 parts to 0.3 parts, the scorch time was adjusted, thus widening the processing safety window. This embodies the "art of balance" in formulation design.

[0093] In summary: Matrix selection: XNBR is a better choice than NBR due to the strong interaction between its carboxyl groups and Ti3C2.

[0094] Optimal content: The Ti3C2 content of 5-6% is a critical inflection point. Within this range, the material achieves a leap in conductivity, wear resistance, and mechanical strength, while avoiding problems such as deteriorated processability and increased costs associated with a high content of 8%.

[0095] Synergistic formulation: The zinc oxide / zinc peroxide compound vulcanization system and the strategy of fine-tuning the CTP dosage in Example 1 effectively optimized the crosslinking structure and processing safety.

Claims

1. A tread rubber composition, characterized in that, The rubber compound includes: nitrile rubber, silica, silane coupling agent, and MXene; wherein the MXene is selected from any one of Ti3C2, V4C3Tx, Nb2CTx, and Ti2CTx.

2. The tread rubber composition according to claim 1, characterized in that, The nitrile rubber is a carboxylated nitrile rubber.

3. The tread rubber composition according to claim 1, characterized in that, The amount of MXene used is not less than 1.5% of the amount of nitrile rubber used.

4. The tread rubber composition according to claim 1, characterized in that, The tread rubber composition further includes: styrene-butadiene rubber, cis-butadiene rubber, and an activator; the activator includes zinc oxide and stearic acid; or the activator includes zinc peroxide and stearic acid; or the activator includes zinc oxide, zinc peroxide, and stearic acid.

5. The tread rubber composition according to claim 4, characterized in that, The tread rubber composition further includes: filler, silane coupling agent, sulfur, accelerator, scorch inhibitor, and antioxidant.

6. The tread rubber composition according to claim 1, characterized in that, By weight, the rubber compound comprises: 100 parts of nitrile rubber, 40-60 parts of silica, 3-5 parts of silane coupling agent, and 3-8 parts of MXene.

7. The tread rubber composition according to claim 5, characterized in that, By weight, the tread rubber composition comprises: 50-70 parts styrene-butadiene rubber, 10-30 parts butadiene rubber, 15-35 parts rubber compound, 70-80 parts filler, 4-8 parts silane coupling agent, 3-7 parts activator, 2-4 parts sulfur, 1-3 parts accelerator, 0.1-0.3 parts anti-scorching agent, and 3-5 parts antioxidant.

8. The method for preparing the tread rubber composition according to any one of claims 1-7, characterized in that, include: First, add nitrile rubber and MXene, press for 40 seconds or raise the temperature to 115°C, remove the pressing wheel, clean, add silica and silane coupling agent, press for 25 seconds or raise the temperature to 145°C, remove the pressing wheel, clean, mix at a constant temperature of 145°C for 60 seconds, discharge the rubber, sheet, cool, and obtain the rubber composite.

9. The method for preparing the tread rubber composition according to claim 8, characterized in that, Also includes: Masterbatch mixing and final rubber mixing; When the surfactant includes zinc oxide and stearic acid: The masterbatch mixing process includes: adding styrene-butadiene rubber, butadiene rubber, rubber compound, silica, silane coupling agent, activator, 4020 and protective wax, pressing with a roller for 30 seconds or raising the temperature to 105°C, lifting the roller, cleaning, pressing with a roller for 30 seconds or raising the temperature to 135°C, lifting the roller, cleaning, pressing with a roller for 40 seconds or raising the temperature to 145°C, lifting the roller, cleaning, mixing at a constant temperature of 145°C for 180 seconds, discharging the glue, sheeting, cooling, and obtaining the masterbatch. The final rubber compounding process includes: adding masterbatch, sulfur, CZ, and CTP; pressing with a roller for 30 seconds or raising the temperature to 85°C; lifting the roller; cleaning; pressing with a roller for 30 seconds or raising the temperature to 105°C; lifting the roller; cleaning; pressing with a roller for 30 seconds or raising the temperature to 110°C; discharging the rubber; sheeting; and cooling. When the surfactant includes zinc peroxide and stearic acid; or when the surfactant includes zinc oxide, zinc peroxide and stearic acid: The masterbatch mixing process includes: adding styrene-butadiene rubber, butadiene rubber, rubber compound, silica, silane coupling agent, 4020 and protective wax, pressing with a roller for 30 seconds or raising the temperature to 105°C, lifting the roller, cleaning, pressing with a roller for 30 seconds or raising the temperature to 135°C, lifting the roller, cleaning, pressing with a roller for 40 seconds or raising the temperature to 145°C, lifting the roller, cleaning, mixing at a constant temperature of 145°C for 180 seconds, discharging the glue, sheeting, cooling, and obtaining the masterbatch. The final rubber compounding process includes: adding masterbatch, activator, sulfur, CZ, and CTP; pressing with a roller for 30 seconds or raising the temperature to 85°C; lifting the roller; cleaning; pressing with a roller for 30 seconds or raising the temperature to 105°C; lifting the roller; cleaning; pressing with a roller for 30 seconds or raising the temperature to 110°C; discharging the rubber; sheeting; and cooling.

10. A tire for new energy vehicles, characterized in that, The tread of the tire for the new energy vehicle is made of the tread rubber composition described in any one of 1-7.

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