Tread rubber composition, tread rubber and method for producing and use thereof

Abstract

The application provides a tread rubber composition, a tread rubber and a preparation method and application thereof. The tread rubber composition comprises, by weight parts, 10-60 parts of modified solution polymerized styrene-butadiene rubber, 1-50 parts of first solution polymerized styrene-butadiene rubber, 1-60 parts of diene rubber, 10-120 parts of white carbon black, 5-40 parts of carbon black, 0.1-20 parts of coupling agent, 0.1-5 parts of vulcanization accelerator and 0.5-10 parts of vulcanizing agent; wherein the modified solution polymerized styrene-butadiene rubber is selected from one or more of hydroxyl modified solution polymerized styrene-butadiene rubber, epoxidized modified solution polymerized styrene-butadiene rubber, maleic anhydride modified solution polymerized styrene-butadiene rubber, silanized modified solution polymerized styrene-butadiene rubber and epoxidized-silanized double modified solution polymerized styrene-butadiene rubber. The above-mentioned tread rubber composition has good compatibility between the components, thereby effectively exerting the synergistic effect of the components and significantly improving the dispersibility of the filler and the interface interaction between the filler and the rubber matrix.

Description

Technical Field

[0001] This application relates to the field of rubber technology, and more specifically, to a tread rubber composition, tread rubber, its preparation method and application. Background Technology

[0002] As a core component of high-performance racing cars, racing tires are designed with a strong focus on maximizing grip and stability in extreme conditions. Racing tires significantly increase grip through the melt effect (rubber softening and adhering to the track surface at high temperatures). They utilize smooth surfaces (for dry tracks) to maximize contact area or wide, deep grooves (for wet tracks) to improve wet traction. Combined with a high-strength, high-rigidity tire carcass, they provide stable support for the race car during rapid acceleration, hard braking, and high-speed cornering.

[0003] The biggest difference between racing tires and ordinary tires is that racing tires pursue the ultimate grip in extreme environments. During the driving process, the intense friction between the tire and the ground and the internal rolling heat will cause the tread temperature to rise rapidly. However, the traditional tread rubber compound has the following technical defects: (1) narrow temperature adaptability and harsh performance window. The rubber is too hard at low temperatures and the grip is insufficient. It is prone to heat decay at high temperatures and is difficult to adapt to the temperature changes of complex tracks; (2) the contradiction between grip and durability is prominent. In order to improve grip, the rubber hardness is reduced, resulting in extremely fast wear. If wear resistance is to be taken into account, the rubber hardness needs to be increased, which reduces the sensitivity of handling feedback; (3) poor performance on wet and slippery surfaces. The traditional compound has limited drainage efficiency, which easily leads to hydroplaning risk and lacks the flexibility to adapt to different road conditions; (4) weak heat generation control ability. Heat continues to accumulate under long-term extreme driving, which easily leads to rubber aging, performance drop and even safety hazards.

[0004] Traditional racing tire tread rubber formulations based on styrene-butadiene rubber also have some inherent defects: (1) low elasticity and large hysteresis loss, which cannot respond quickly to changes in the track surface, resulting in sluggish grip feedback and affecting handling accuracy; (2) high heat generation, which easily accumulates heat during high-speed driving or intense friction, thereby accelerating tread softening and heat decay, and shortening track lifespan; (3) poor wet skid resistance, which cannot effectively adhere to the ground in rainy or waterlogged tracks, increasing the risk of slippage and making it difficult to meet track requirements under complex weather conditions; (4) insufficient adhesion and tear resistance, with weak bonding between rubber molecules, which easily leads to cracks and rapid expansion, which may affect structural stability under extreme stress; (5) slow vulcanization speed, which makes it difficult to control plasticity during processing and makes it difficult to match the high requirements of racing tires for production precision and performance consistency.

[0005] Existing hot melt tread rubber compositions typically use a large amount of silica filler to achieve good abrasion resistance and grip performance. However, this method has problems such as filler agglomeration, difficulty in dispersion, and weak filler-rubber interaction, which makes it difficult for the rubber compound performance to meet expectations. Existing literature (publication number CN116790054A) discloses a semi-hot melt adhesive compound and its mixing process. The compound comprises: 100-113 parts solution-polymerized styrene-butadiene rubber; 15-25 parts BR9000 butadiene rubber; 13-18 parts highly dispersed silica; 1-2 parts silane coupling agent; 25-28 parts hot melt-specific liquid resin; 70-75 parts carbon black N234; 2.5-3.5 parts zinc oxide; 1.5-2.5 parts stearic acid; 1-2 parts protective wax; 2-2.5 parts antioxidant 4020; 1-1.5 parts antioxidant RD; 4.5-5 parts phenolic resin; 2-2.5 parts polypropylene; 3-3.2 parts insoluble 21% oil-extended sulfur; 1.2-1.5 parts accelerator TBBS (NS); and accelerator D. 0.3–0.5 parts; anti-scorching agent 0.15–0.25 parts. However, due to the numerous defects mentioned above in traditional styrene-butadiene rubber, the racing tire tread compound in this paper, which is mainly composed of styrene-butadiene rubber and traditional butadiene rubber, is prone to problems such as hysteresis loss and unbalanced elasticity, resulting in reduced high-temperature grip, wet grip, and wear performance of racing tires. Currently, most commercially available racing tires suffer from problems such as poor high-temperature resistance of the tread rubber composition, unsatisfactory high-temperature grip, excessively long warm-up time, rapid thermal decay, poor wear resistance, and short service life.

[0006] In summary, this study has developed a tread rubber composition, tread rubber, and preparation method that exhibit strong high-temperature grip, excellent high-temperature resistance, short warm-up time, and good wear resistance. While achieving high wear resistance in the tread rubber, it also addresses the problem of filler dispersion and improves the interaction between the rubber and filler, which is of great significance for enhancing the safety and performance of racing tires. Summary of the Invention

[0007] The main objective of this application is to provide a tread rubber composition, tread rubber, preparation method and application thereof, in order to solve the problems of poor high temperature resistance, rapid heat decay, unsatisfactory high temperature grip and poor wear resistance of the tread rubber of racing tires due to poor filler dispersion and weak interaction between rubber and filler.

[0008] To achieve the above objectives, this application provides a tread rubber composition, which, by weight, comprises: 10-60 parts of modified solution-polymerized styrene-butadiene rubber, 1-50 parts of a first solution-polymerized styrene-butadiene rubber, 1-60 parts of diene rubber, 10-120 parts of silica, 5-40 parts of carbon black, 0.1-20 parts of coupling agent, 0.1-5 parts of vulcanization accelerator, and 0.5-10 parts of vulcanizing agent; the modified solution-polymerized styrene-butadiene rubber is selected from one or more of hydroxyl-modified solution-polymerized styrene-butadiene rubber, epoxidized solution-polymerized styrene-butadiene rubber, maleic anhydride-modified solution-polymerized styrene-butadiene rubber, silanized solution-polymerized styrene-butadiene rubber, and epoxidized-silanized dual-modified solution-polymerized styrene-butadiene rubber.

[0009] Further, by weight, the tread rubber composition comprises: 20-40 parts modified solution-polymerized styrene-butadiene rubber, 5-40 parts primary solution-polymerized styrene-butadiene rubber, 10-60 parts diene rubber, 20-90 parts silica, 10-30 parts carbon black, 1-15 parts coupling agent, 0.5-1.5 parts vulcanization accelerator and 1-3 parts vulcanizing agent.

[0010] Furthermore, the hydroxyl-modified solution-polymerized styrene-butadiene rubber has the chemical formula shown in formula (I):

[0011] (I); where x1 is an integer between 1800 and 2600, n1 is an integer between 10 and 50, and m1 is an integer between 540 and 630.

[0012] Furthermore, the epoxidized solution-polymerized styrene-butadiene rubber has the chemical formula shown in formula (II):

[0013] (II); where x2 is an integer between 2100 and 2600, n2 is an integer between 20 and 90, and m2 is an integer between 550 and 640.

[0014] Furthermore, maleic anhydride-modified solution-polymerized styrene-butadiene rubber has the chemical formula shown in formula (III):

[0015] (III); where x3 is an integer between 2300 and 2950, ​​n3 is an integer between 10 and 50, and m3 is an integer between 560 and 700.

[0016] Furthermore, the silanized solution-polymerized styrene-butadiene rubber has the chemical formula shown in formula (IV):

[0017] (IV); where x4 is an integer between 2600 and 3050, n4 is an integer between 5 and 20, and m4 is an integer between 545 and 615.

[0018] Furthermore, the epoxidized-silanized dual-modified solution-polymerized styrene-butadiene rubber has the chemical formula shown in formula (V):

[0019] (V); where x5 is an integer between 2650 and 3440, n5 is an integer between 30 and 90, n6 is an integer between 12 and 25, and m5 is an integer between 575 and 675.

[0020] Further, the number-average relative molecular mass of the hydroxyl-modified solution-polymerized styrene-butadiene rubber is 180,000 to 200,000 g / mol; preferably, the glass transition temperature of the hydroxyl-modified solution-polymerized styrene-butadiene rubber is -54.4 to -51.6 °C; preferably, in the hydroxyl-modified solution-polymerized styrene-butadiene rubber, The content of styrene is 1.0 to 3.0 wt%, and the content of the corresponding chain segment of styrene is 30 to 32 wt%.

[0021] Further, the number-average relative molecular mass of the epoxidized solution-polymerized styrene-butadiene rubber is 190,000 to 200,000 g / mol; preferably, the glass transition temperature of the epoxidized solution-polymerized styrene-butadiene rubber is -46.5 to -42.3 °C; preferably, in the epoxidized solution-polymerized styrene-butadiene rubber, The content of styrene is 1.0 to 3.0 wt%, and the content of the corresponding chain segment of styrene is 31 to 33 wt%.

[0022] Furthermore, the number-average relative molecular mass of the maleic anhydride-modified solution-polymerized styrene-butadiene rubber is 210,000 to 220,000 g / mol; preferably, the glass transition temperature of the maleic anhydride-modified solution-polymerized styrene-butadiene rubber is -55.5 to -52.7 °C; preferably, in the maleic anhydride-modified solution-polymerized styrene-butadiene rubber, The content of styrene is 1.0 to 3.0 wt%, and the content of the corresponding styrene segments is 29 to 33 wt%.

[0023] Further, the number-average relative molecular mass of the silanized modified solution-polymerized styrene-butadiene rubber is 210,000 to 220,000 g / mol; preferably, the glass transition temperature of the silanized modified solution-polymerized styrene-butadiene rubber is -57.0 to -54.0 °C; preferably, in the silanized modified solution-polymerized styrene-butadiene rubber, The content of styrene is 1.0 to 3.0 wt%, and the content of the corresponding styrene segments is 27 to 29 wt%.

[0024] Further, the number-average relative molecular mass of the epoxidized-silanized dual-modified solution-polymerized styrene-butadiene rubber is 230,000 to 250,000 g / mol; preferably, the glass transition temperature of the epoxidized-silanized dual-modified solution-polymerized styrene-butadiene rubber is -58.5 to -55.4 °C; preferably, in the epoxidized-silanized dual-modified solution-polymerized styrene-butadiene rubber, The content is 0.9–2.5 wt%. The content of styrene is 2.0–3.2 wt%, and the content of the corresponding styrene segments is 26–28 wt%.

[0025] Further, the preparation method of hydroxyl-modified solution polymerized styrene-butadiene rubber includes: under the action of an initiator, 2-mercaptoethanol and a second solution polymerized styrene-butadiene rubber undergo a first mercapto-olefin click chemical reaction to obtain hydroxyl-modified solution polymerized styrene-butadiene rubber; preferably, the weight ratio of 2-mercaptoethanol to the second solution polymerized styrene-butadiene rubber is 1:(5-10); the initiator accounts for 0.1-2 wt% of the weight of the second solution polymerized styrene-butadiene rubber; the initiator is selected from one or more of dodecanoyl peroxide, tert-butyl hydroperoxide, and azobisisoheptanenitrile; preferably, the temperature of the first mercapto-olefin click chemical reaction is 80-95°C, and the time is 0.5-3.5 h.

[0026] Further, the preparation method of epoxidized solution-polymerized styrene-butadiene rubber includes: under the action of an oxidant, formic acid and a second solution-polymerized styrene-butadiene rubber undergo a first epoxidation reaction to obtain epoxidized solution-polymerized styrene-butadiene rubber; preferably, the weight ratio of the second solution-polymerized styrene-butadiene rubber to formic acid is 1:(5-10); the weight ratio of the second solution-polymerized styrene-butadiene rubber to the oxidant is 1:(3-10); the oxidant is selected from one or more of hydrogen peroxide, tert-butyl hydroperoxide, and cumene peroxide; preferably, the temperature of the first epoxidation reaction is 45-80°C, and the time is 1-4.5 h.

[0027] Furthermore, the preparation method of maleic anhydride-modified solution polymerized styrene-butadiene rubber includes: under the action of an initiator, maleic anhydride and a second solution polymerized styrene-butadiene rubber undergo an addition reaction to obtain maleic anhydride-modified solution polymerized styrene-butadiene rubber; preferably, the weight percentage of maleic anhydride in the second solution polymerized styrene-butadiene rubber is 5-20 wt%; the weight percentage of the initiator in the second solution polymerized styrene-butadiene rubber is 0.1-2 wt%; preferably, the temperature of the addition reaction is 120-180°C, and the time is 2-6 h.

[0028] Furthermore, the preparation method of silanized modified solution polymerized styrene-butadiene rubber includes: under the action of an initiator, 3-mercaptotripropoxysilane undergoes a second mercapto-olefin click chemical reaction with the second solution polymerized styrene-butadiene rubber to obtain silanized modified solution polymerized styrene-butadiene rubber; preferably, the weight ratio of 3-mercaptotripropoxysilane to the second solution polymerized styrene-butadiene rubber is (1-10):100; the weight percentage of the initiator in the second solution polymerized styrene-butadiene rubber is 0.1-2 wt%; preferably, the temperature of the second mercapto-olefin click chemical reaction is 80-100℃, and the time is 0.5-2.5 h.

[0029] Further, the preparation method of epoxidized-silanized dual-modified solution-polymerized styrene-butadiene rubber includes: under the action of an oxidant, formic acid and a second solution-polymerized styrene-butadiene rubber undergo a second epoxidation reaction to obtain an epoxidized modified solution-polymerized styrene-butadiene rubber intermediate; under the action of an initiator, the epoxidized modified solution-polymerized styrene-butadiene rubber intermediate undergoes a third mercapto-olefin click chemical reaction with 3-mercaptotripropoxysilane to obtain epoxidized-silanized dual-modified solution-polymerized styrene-butadiene rubber; preferably, the weight ratio of the second solution-polymerized styrene-butadiene rubber to formic acid is 1:(5-10); the weight ratio of the second solution-polymerized styrene-butadiene rubber to the oxidant... The weight ratio is 1:(3-10); the oxidant is selected from one or more of hydrogen peroxide, tert-butyl hydrogen peroxide and cumene peroxide; the temperature of the second epoxidation reaction is 45-80℃ and the time is 1-4.5h; preferably, the weight ratio of 3-mercaptotripropoxysilane to the epoxidation-modified solution-polymerized styrene-butadiene rubber intermediate is (15-25):100; the initiator accounts for 0.5-2.5 wt% of the weight of the epoxidation-modified solution-polymerized styrene-butadiene rubber intermediate; the temperature of the third mercapto-olefin click chemistry reaction is 80-110℃ and the time is 1-3.5h.

[0030] Furthermore, the weight-average molecular weight of the first solution-polymerized styrene-butadiene rubber is 250,000 to 350,000 g / mol.

[0031] Furthermore, the diene rubber has a weight-average molecular weight of 300,000 to 450,000 g / mol and an unsaturated double bond content of 97.5 to 99.5 wt%; preferably, the diene rubber is selected from natural rubber and / or polyisoprene rubber.

[0032] Furthermore, the coupling agent is a silane coupling agent.

[0033] Furthermore, the vulcanization accelerator is selected from one or more of N-cyclohexyl-2-benzothiazole sulfenamide, N-tert-butyl-2-benzothiazole sulfenamide, and dibenzothiazole disulfide.

[0034] Furthermore, the vulcanizing agent is sulfur.

[0035] Furthermore, the tread rubber composition further includes functional additives; preferably, the functional additives are present in parts by weight of 30 to 140; preferably, the functional additives include one or more of anti-slip resin, bio-based plasticizer, zinc oxide, stearic acid, and antioxidant; preferably, by weight, the functional additives include: 5 to 80 parts of anti-slip resin, 5 to 30 parts of bio-based plasticizer, 0.5 to 10 parts of zinc oxide, 0.2 to 10 parts of stearic acid, and 1 to 10 parts of antioxidant.

[0036] To achieve the above objectives, another aspect of this application provides a tread rubber, which is obtained by mixing and vulcanizing the tread rubber composition provided in this application.

[0037] Another aspect of this application provides a method for preparing the above-mentioned tread rubber provided in this application. The preparation method includes: step S1, mixing modified solution-polymerized styrene-butadiene rubber, first solution-polymerized styrene-butadiene rubber, diene rubber, silica, carbon black and coupling agent to obtain masterbatch; step S2, mixing masterbatch, vulcanization accelerator and vulcanizing agent to obtain compound; step S3, vulcanizing compound to obtain tread rubber.

[0038] Furthermore, functional additives are introduced during the mixing process in step S1; preferably, the mixing time in step S1 is 6 to 22 minutes; preferably, stirring is carried out during the mixing process in step S1, and more preferably, the stirring rate is 60 to 85 rpm; preferably, the glue is also discharged after mixing in step S1, and more preferably, the glue discharge temperature is 140 to 148°C.

[0039] Furthermore, in step S2, the mixing temperature is 45–65°C, and the time is 8–10 min.

[0040] Furthermore, in step S3, the vulcanization temperature is 150–175°C, the pressure is 5–8 MPa, and the time is 8–20 min.

[0041] The fourth aspect of this application also provides the above-described tread rubber composition provided in this application, or the application of the above-described tread rubber provided in this application in racing tires.

[0042] This application provides a tread rubber composition with a specific type of modified solution-polymerized styrene-butadiene rubber (SBR) as the core functional component. This significantly improves the compatibility of the components in the tread rubber composition, thereby effectively leveraging the synergistic effect of each component and significantly improving the dispersibility of the filler and its interfacial interaction with the rubber matrix. By introducing modified SBR containing polar groups (such as hydroxyl, epoxy, anhydride, and silane groups), the tread rubber can form weak hydrogen bonds with water molecules on wet surfaces, thereby enhancing the tread rubber's grip and improving its anti-skid ability. Furthermore, the above-mentioned tread rubber composition possesses a stable physical cross-linked network structure. The tread rubber made from the above-mentioned tread rubber composition provided in this application has good structural stability, high-temperature grip performance, wear resistance and wet skid resistance. When it is used as tread rubber in racing tires, the loss factor (tanδ) in the high-temperature zone (40-80°C) can show an increasing trend and tend to stabilize while maintaining the appropriate glass transition temperature of the hot melt tread rubber. This allows the tread rubber to maintain excellent grip performance in high-temperature environments (60-110°C) and also meets the core requirements of racing tires for high-temperature melt processing and high elasticity after cooling. Detailed Implementation

[0043] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present application will now be described in detail with reference to the embodiments.

[0044] As described in the background section, existing racing tire tread rubbers suffer from poor filler dispersion and weak interaction between the rubber and fillers, resulting in poor high-temperature resistance, rapid heat decay, unsatisfactory high-temperature grip, and poor wear resistance. To address these technical problems, this application provides a tread rubber composition, comprising, by weight: 10-60 parts modified solution-polymerized styrene-butadiene rubber (SBR), 1-50 parts of a first solution-polymerized SBR, 1-60 parts of a diene rubber, 10-120 parts of silica, 5-40 parts of carbon black, 0.1-20 parts of a coupling agent, 0.1-5 parts of a vulcanization accelerator, and 0.5-10 parts of a vulcanizing agent; wherein the modified solution-polymerized SBR is selected from one or more of hydroxyl-modified solution-polymerized SBR, epoxidized modified solution-polymerized SBR, maleic anhydride-modified solution-polymerized SBR, silanized modified solution-polymerized SBR, and epoxidized-silanized dual-modified solution-polymerized SBR.

[0045] The tread rubber composition provided in this application uses a specific type of modified solution-polymerized styrene-butadiene rubber as the core functional component, which significantly improves the compatibility of each component in the tread rubber composition, thereby effectively exerting the synergistic effect of each component and significantly improving the dispersibility of the filler and its interfacial interaction with the rubber matrix.

[0046] Firstly, the hydroxyl groups in hydroxyl-modified solution-polymerized styrene-butadiene rubber (HO-SSBR) are highly polar. They can not only form hydrogen bonds with the silanol groups on the surface of silica filler, but also undergo dehydration condensation with silica to form covalent bonds. This effectively improves the interfacial compatibility between HO-SSBR and silica, significantly improves the dispersion of silica in the rubber matrix, and inhibits its agglomeration, thereby improving the mechanical properties and reinforcing effect of the tread rubber. At the same time, due to the improved dispersibility of the filler, the internal frictional heat generation of the filler is greatly reduced, and the heat accumulation in the tread is reduced, which can effectively alleviate the softening and thermal degradation of rubber under high temperature (60-110℃) conditions.

[0047] Secondly, epoxidized solution-polymerized styrene-butadiene rubber (E-SSBR) effectively improves the polarity of E-SSBR and its compatibility with hydrophilic substances by introducing epoxy groups into the SSBR backbone, thereby enhancing the interaction between the tread rubber and water molecules on wet and slippery surfaces and improving wet grip performance. At the same time, the rigid structure of the epoxy groups helps to improve the storage modulus (E') and loss factor (tanδ) of the tread rubber, enhancing the energy dissipation capacity of the tread rubber under dynamic loads. In addition, the epoxy groups can form a strong interfacial interaction with the silanol groups on the surface of silica fillers, thereby enhancing the interfacial bonding force between the rubber matrix and the fillers, weakening the Payne effect, and thus significantly improving the dispersibility of the fillers.

[0048] Thirdly, maleic anhydride-modified solution-polymerized styrene-butadiene rubber (M-SSBR) introduces a five-membered cyclic anhydride group with strong polarity and high reactivity by grafting maleic anhydride groups onto the SSBR main chain. This group can not only act as a reaction site to react with the silanol groups on the surface of silica, but also significantly enhance the compatibility of M-SSBR with polar fillers through polar interactions such as hydrogen bonding, promote the uniform dispersion of fillers, and improve the interfacial bonding force between the rubber matrix and the fillers, thereby improving the mechanical properties of the tread rubber.

[0049] Fourthly, silanized solution-polymerized styrene-butadiene rubber (Si-SSBR) introduces silane groups into its molecular chain. The silanol groups generated by the hydrolysis of its silanoxy groups undergo dehydration condensation with the silanol groups on the surface of silica, thereby breaking the hydrogen bond aggregation between silica particles, significantly improving the dispersibility of fillers in the rubber matrix, reducing internal friction of fillers, weakening the Payne effect, and thus improving the mechanical properties of the obtained tread rubber.

[0050] Fifthly, the epoxidized-silanized solution-modified styrene-butadiene rubber (E-Si-SSBR) utilizes a synergistic mechanism of dual interfacial bonding at the rubber-fumed silica filler interface by introducing epoxy and silane groups. The epoxy groups form hydrogen and covalent bonds with the silanol groups on the silica surface, increasing the polarity of the rubber matrix and improving its compatibility with polar silica. The silane groups bond with the silanol groups on the silica surface through Si-O-Si covalent bonds, significantly enhancing the interfacial bonding between the rubber matrix and the filler. Simultaneously, the epoxy and silane groups form complementary interfacial layers on the silica surface. The epoxy groups cover most of the silica surface, while the silane groups form strong covalent bonds at key sites, jointly inhibiting the aggregation of silica particles and significantly improving filler dispersibility.

[0051] This application introduces modified solution-polymerized styrene-butadiene rubber (SBR) containing the aforementioned specific polar groups (hydroxyl, epoxy, anhydride, and silane groups), enabling the tread rubber to form weak hydrogen bonds with water molecules on wet, slippery surfaces, thereby enhancing the tread rubber's grip and improving its anti-skid ability. Furthermore, the aforementioned tread rubber composition possesses a stable physical cross-linked network structure. Specifically, on one hand, the macromolecular chains of the modified solution-polymerized SBR, the first solution-polymerized SBR, and the diene rubber intertwine to form a relatively stable basic physical network structure; on the other hand, the physical adsorption between the modified solution-polymerized SBR and the filler further enhances the continuity and stability of the physical cross-linked network structure.

[0052] Compared to other ranges, limiting the weight percentages of each component in the tread rubber composition to the above-mentioned specific range can improve the processability of the tread rubber composition and effectively enhance the synergistic effect between the components, improve the dispersibility of the filler and its interfacial interaction with the rubber, thereby significantly improving the grip, wear resistance, thermal stability and wet skid resistance of the obtained tread rubber.

[0053] In summary, the tread rubber made from the above-mentioned tread rubber composition provided in this application has good structural stability, high-temperature grip performance, wear resistance and wet skid resistance. When it is used as tread rubber in racing tires, the loss factor (tanδ) in the high-temperature zone can show an increasing trend and tend to stabilize while maintaining the appropriate glass transition temperature of the hot melt tread rubber. This allows the tread rubber to maintain excellent grip performance in high-temperature environments, while also meeting the core requirements of racing tires for high-temperature melt processing and high elasticity after cooling.

[0054] To further improve the processability of the tread rubber composition, enhance the synergistic effect between the components, improve the dispersibility of the filler and its interfacial interaction with the rubber, thereby further improving the grip, wear resistance, thermal stability and wet skid resistance of the obtained tread rubber, in a preferred embodiment, the tread rubber composition comprises, by weight: 20-40 parts modified solution-polymerized styrene-butadiene rubber, 5-40 parts primary solution-polymerized styrene-butadiene rubber, 10-60 parts diene rubber, 20-90 parts silica, 10-30 parts carbon black, 1-15 parts coupling agent, 0.5-1.5 parts vulcanization accelerator and 1-3 parts vulcanizing agent.

[0055] To further enhance the synergistic effect of modified solution-polymerized styrene-butadiene rubber (SBR), thereby improving the compatibility of the components in the tread rubber composition and further improving the dispersibility of the filler and its interfacial interaction with the rubber matrix, preferably, the modified SBR is selected from a combination of hydroxyl-modified SBR and epoxidized SBR, with a weight ratio of (5-15):(5-15); or, a combination of hydroxyl-modified SBR and maleic anhydride-modified SBR, with a weight ratio of (5-15):(5-15); or, a combination of hydroxyl-modified SBR and maleic anhydride-modified SBR. A combination of styrene rubber and silanized modified solution-polymerized styrene-butadiene rubber, wherein the weight ratio of the two is (5-15):(5-20); or, a combination of maleic anhydride modified solution-polymerized styrene-butadiene rubber and silanized modified solution-polymerized styrene-butadiene rubber, wherein the weight ratio of the two is (5-15):(5-20); or, a combination of epoxidized modified solution-polymerized styrene-butadiene rubber and silanized modified solution-polymerized styrene-butadiene rubber, wherein the weight ratio of the two is (5-15):(5-20); or, a combination of epoxidized modified solution-polymerized styrene-butadiene rubber and maleic anhydride modified solution-polymerized styrene-butadiene rubber, wherein the weight ratio of the two is (5-15):(5-15).

[0056] In a preferred embodiment, the hydroxyl-modified solution-polymerized styrene-butadiene rubber has the chemical formula shown in formula (I):

[0057] (I); where x1 is an integer between 1800 and 2600, n1 is an integer between 10 and 50, and m1 is an integer between 540 and 630. Compared with other structures, hydroxyl-modified solution-polymerized styrene-butadiene rubber with the chemical structure shown in formula (I) above is beneficial to improving the interfacial compatibility between HO-SSBR and silica, improving the dispersibility of silica in the rubber matrix, and inhibiting its agglomeration, thereby improving the mechanical properties and reinforcing effect of the obtained tread rubber.

[0058] To further improve the interfacial compatibility between HO-SSBR and silica, and to improve the dispersibility of silica in the rubber matrix, preferably, the number-average molecular weight of the hydroxyl-modified solution-polymerized styrene-butadiene rubber is 180,000 to 200,000 g / mol, and the glass transition temperature is -54.4 to -51.6 °C; preferably, in the hydroxyl-modified solution-polymerized styrene-butadiene rubber, The content of styrene is 1.0 to 3.0 wt%, and the content of the corresponding chain segment of styrene is 30 to 32 wt%.

[0059] In order to obtain a hydroxyl-modified solution-polymerized styrene-butadiene rubber with a more suitable structure and better performance, thereby further improving the interfacial compatibility between HO-SSBR and silica and improving the dispersibility of silica in the rubber matrix, in a preferred embodiment, the preparation method of hydroxyl-modified solution-polymerized styrene-butadiene rubber includes: under the action of an initiator, causing 2-mercaptoethanol to undergo a first mercapto-olefin click chemical reaction with a second solution-polymerized styrene-butadiene rubber to obtain hydroxyl-modified solution-polymerized styrene-butadiene rubber.

[0060] To further improve the reaction efficiency of the first mercapto-olefin click chemistry reaction and obtain a hydroxyl-modified solution-polymerized styrene-butadiene rubber with a more suitable structure and superior performance, preferably, the weight ratio of 2-mercaptoethanol to the second solution-polymerized styrene-butadiene rubber is 1:(5-10); preferably, the initiator accounts for 0.1-2 wt% of the weight of the second solution-polymerized styrene-butadiene rubber; preferably, the initiator includes, but is not limited to, one or more of dodecanoyl peroxide, tert-butyl hydroperoxide, and azobisisoheptanenitrile; preferably, the temperature of the first mercapto-olefin click chemistry reaction is 80-95°C, and the time is 0.5-3.5 h.

[0061] In a preferred embodiment, the epoxidized solution-polymerized styrene-butadiene rubber has the chemical formula shown in formula (II):

[0062] (II); where x2 is an integer between 2100 and 2600, n2 is an integer between 20 and 90, and m2 is an integer between 550 and 640. Compared with other structures, epoxidized solution-modified styrene-butadiene rubber with the chemical structure shown in formula (II) above is beneficial to improving the interfacial compatibility between E-SSBR and other components, enhancing the energy dissipation capacity of the tread rubber under dynamic load, and also beneficial to improving the dispersion of silica in the rubber matrix.

[0063] To further improve the interfacial compatibility of E-SSBR with other components and enhance the dispersibility of silica in the rubber matrix, preferably, the number-average molecular weight of the epoxidized solution-polymerized styrene-butadiene rubber is 190,000 to 200,000 g / mol, and the glass transition temperature is -46.5 to -42.3 °C; preferably, in the epoxidized solution-polymerized styrene-butadiene rubber, The content of styrene is 1.0 to 3.0 wt%, and the content of the corresponding chain segment of styrene is 31 to 33 wt%.

[0064] In order to obtain an epoxidized solution-polymerized styrene-butadiene rubber with a more suitable structure and better performance, thereby further improving the interfacial compatibility of E-SSBR with other components, in a preferred embodiment, the preparation method of epoxidized solution-polymerized styrene-butadiene rubber includes: under the action of an oxidant, formic acid and a second solution-polymerized styrene-butadiene rubber undergo a first epoxidation reaction to obtain epoxidized solution-polymerized styrene-butadiene rubber.

[0065] To further improve the reaction efficiency of the first epoxidation reaction and obtain an epoxidized solution-polymerized styrene-butadiene rubber with a more suitable structure and superior performance, preferably, the weight ratio of the second solution-polymerized styrene-butadiene rubber to formic acid is 1:(5-10); preferably, the weight ratio of the second solution-polymerized styrene-butadiene rubber to the oxidant is 1:(3-10); preferably, the oxidant includes, but is not limited to, one or more of hydrogen peroxide, tert-butyl hydrogen peroxide, and cumene peroxide; preferably, the temperature of the first epoxidation reaction is 45-80°C, and the time is 1-4.5 h.

[0066] In a preferred embodiment, the maleic anhydride-modified solution-polymerized styrene-butadiene rubber has the chemical formula shown in formula (III):

[0067] (III); where x3 is an integer between 2300 and 2950, ​​n3 is an integer between 10 and 50, and m3 is an integer between 560 and 700. Compared with other structures, maleic anhydride-modified solution-polymerized styrene-butadiene rubber with the chemical structure shown in formula (III) above is beneficial to improving the interfacial compatibility between M-SSBR and polar fillers, and to improving the dispersion of silica in the rubber matrix and its interfacial bonding force with the rubber matrix, thereby improving the mechanical properties of the obtained tread rubber.

[0068] To further improve the interfacial compatibility between M-SSBR and polar fillers, and to further improve the dispersibility of silica in the rubber matrix and its interfacial bonding force with the rubber matrix, in a preferred embodiment, the number-average relative molecular mass of the maleic anhydride-modified solution-polymerized styrene-butadiene rubber is 210,000 to 220,000 g / mol, and the glass transition temperature is -55.5 to -52.7 °C; preferably, in the maleic anhydride-modified solution-polymerized styrene-butadiene rubber, The content of styrene is 1.0 to 3.0 wt%, and the content of the corresponding styrene segments is 29 to 33 wt%.

[0069] In order to obtain maleic anhydride-modified solution-polymerized styrene-butadiene rubber with a more suitable structure and better performance, thereby further improving the interfacial compatibility between M-SSBR and polar fillers, and further improving the dispersibility of silica in the rubber matrix and its interfacial bonding force with the rubber matrix, in a preferred embodiment, the preparation method of maleic anhydride-modified solution-polymerized styrene-butadiene rubber includes: under the action of an initiator, maleic anhydride and a second solution-polymerized styrene-butadiene rubber undergo an addition reaction to obtain maleic anhydride-modified solution-polymerized styrene-butadiene rubber.

[0070] To further improve the reaction efficiency of the addition reaction and obtain a maleic anhydride-modified solution-polymerized styrene-butadiene rubber with a more suitable structure and superior performance, preferably, the weight percentage of maleic anhydride in the second solution-polymerized styrene-butadiene rubber is 5-20 wt%; preferably, the weight percentage of the initiator in the second solution-polymerized styrene-butadiene rubber is 0.1-2 wt%; preferably, the initiator includes, but is not limited to, one or more of dodecanoyl peroxide, tert-butyl hydroperoxide, and azobisisobutyronitrile; preferably, the addition reaction temperature is 120-180°C and the time is 2-6 h.

[0071] In a preferred embodiment, the silanized solution-polymerized styrene-butadiene rubber has the chemical formula shown in formula (IV):

[0072] (IV); where x4 is an integer between 2600 and 3050, n4 is an integer between 5 and 20, and m4 is an integer between 545 and 615. Compared with other structures, silanized modified solution-polymerized styrene-butadiene rubber with the chemical structure shown in formula (IV) above is beneficial to improving the interfacial compatibility between Si-SSBR and polar fillers, while also promoting the uniform dispersion of fillers and enhancing the interfacial bonding force between fillers and the rubber matrix, thereby improving the mechanical properties of the obtained tread rubber.

[0073] To further improve the interfacial compatibility between Si-SSBR and polar fillers, further promote the uniform dispersion of fillers, and enhance the interfacial bonding force between fillers and the rubber matrix, in a preferred embodiment, the number-average relative molecular mass of the silanized solution-polymerized styrene-butadiene rubber is 210,000 to 220,000 g / mol, and the glass transition temperature is -57.0 to -54.0 °C; preferably, in the silanized solution-polymerized styrene-butadiene rubber, The content of styrene is 1.0 to 3.0 wt%, and the content of the corresponding styrene segments is 27 to 29 wt%.

[0074] In order to obtain a silanized modified solution-polymerized styrene-butadiene rubber with a more suitable structure and better performance, thereby further improving the interfacial compatibility between Si-SSBR and polar fillers, further promoting the uniform dispersion of fillers, and enhancing the interfacial bonding force between fillers and rubber matrix, in a preferred embodiment, the preparation method of silanized modified solution-polymerized styrene-butadiene rubber includes: under the action of an initiator, causing 3-mercaptotripropoxysilane to undergo a second mercapto-olefin click chemical reaction with the second solution-polymerized styrene-butadiene rubber to obtain silanized modified solution-polymerized styrene-butadiene rubber.

[0075] To further improve the reaction efficiency of the second mercapto-olefin click chemistry reaction and obtain a silanized modified styrene-butadiene rubber with a more suitable structure and superior performance, preferably, the weight ratio of 3-mercaptotripropoxysilane to the second solution-polymerized styrene-butadiene rubber is (1-10):100; preferably, the initiator accounts for 0.1-2 wt% of the weight of the second solution-polymerized styrene-butadiene rubber; preferably, the initiator includes, but is not limited to, one or more of dodecanoyl peroxide, tert-butyl hydroperoxide, and azobisisoheptanenitrile; preferably, the temperature of the second mercapto-olefin click chemistry reaction is 80-100°C, and the time is 0.5-2.5 h.

[0076] In a preferred embodiment, the epoxidized-silanized dual-modified solution-polymerized styrene-butadiene rubber has the chemical formula shown in formula (V):

[0077] (V); where x5 is an integer between 2650 and 3440, n5 is an integer between 30 and 90, n6 is an integer between 12 and 25, and m5 is an integer between 575 and 675. Compared with other structures, the epoxidized-silanized dual-modified solution-polymerized styrene-butadiene rubber with the chemical structure shown in the above formula (V) is beneficial to forming a synergistic mechanism of dual interfacial bonding at the interface between the rubber and the silica filler, promoting the formation of complementary interfacial layers between epoxy groups and silane groups on the silica surface, thereby improving the interfacial compatibility between E-Si-SSBR and polar fillers, enhancing the interfacial bonding force between the filler and the rubber matrix, and thus improving the mechanical properties of the obtained tread rubber.

[0078] To further improve the interfacial compatibility between E-Si-SSBR and polar fillers, enhance the interfacial bonding force between the filler and the rubber matrix, and thus improve the mechanical properties of the resulting tread rubber, in a preferred embodiment, the number-average relative molecular mass of the epoxidized-silanized dual-modified solution-polymerized styrene-butadiene rubber is 230,000 to 250,000 g / mol, and the glass transition temperature is -58.5 to -55.4 °C; preferably, in the epoxidized-silanized dual-modified solution-polymerized styrene-butadiene rubber, The content is 0.9–2.5 wt%. The content of styrene is 2.0–3.2 wt%, and the content of the corresponding styrene segments is 26–28 wt%.

[0079] To obtain an epoxidized-silanized modified solution-polymerized styrene-butadiene rubber with a more suitable structure and superior performance, thereby further improving the interfacial compatibility between E-Si-SSBR and polar fillers, and further improving the dispersibility of silica in the rubber matrix and its interfacial bonding force with the rubber matrix, in a preferred embodiment, the preparation method of the epoxidized-silanized dual-modified solution-polymerized styrene-butadiene rubber includes: under the action of an oxidant, formic acid and a second solution-polymerized styrene-butadiene rubber undergo a second epoxidation reaction to obtain an epoxidized modified solution-polymerized styrene-butadiene rubber intermediate; under the action of an initiator, the epoxidized modified solution-polymerized styrene-butadiene rubber intermediate undergoes a third mercapto-olefin click chemical reaction with 3-mercaptotripropoxysilane to obtain the epoxidized-silanized dual-modified solution-polymerized styrene-butadiene rubber.

[0080] To further improve the reaction efficiency of the second epoxidation reaction and obtain an epoxidation-modified solution-polymerized styrene-butadiene rubber intermediate with a more suitable structure and superior performance, preferably, the weight ratio of the second solution-polymerized styrene-butadiene rubber to formic acid is 1:(5-10); preferably, the weight ratio of the second solution-polymerized styrene-butadiene rubber to the oxidant is 1:(3-10); preferably, the oxidant includes, but is not limited to, one or more of hydrogen peroxide, tert-butyl hydroperoxide, and cumene peroxide; preferably, the temperature of the second epoxidation reaction is 45-80°C, and the time is 1-4.5 h.

[0081] To further improve the reaction efficiency of the third mercapto-olefin click chemistry reaction and obtain an epoxidation-silanization dual-modified solution-polymerized styrene-butadiene rubber with a more suitable structure and superior performance, preferably, the weight ratio of 3-mercaptotripropoxysilane to the epoxidation-modified solution-polymerized styrene-butadiene rubber intermediate is (15-25):100; preferably, the initiator accounts for 0.5-2.5 wt% of the weight of the epoxidation-modified solution-polymerized styrene-butadiene rubber intermediate; preferably, the initiator includes, but is not limited to, one or more of dodecanoyl peroxide, tert-butyl hydroperoxide, and azobisisoheptanenitrile; preferably, the temperature of the third mercapto-olefin click chemistry reaction is 80-110°C, and the time is 1-3.5 h.

[0082] In order to improve the mechanical properties of the first solution-polymerized styrene-butadiene rubber and its compatibility with other components, in a preferred embodiment, the weight-average molecular weight of the first solution-polymerized styrene-butadiene rubber is 250,000 to 350,000 g / mol.

[0083] In order to improve the mechanical properties of diene rubber and its compatibility with other components, in a preferred embodiment, the weight-average molecular weight of the diene rubber is 300,000 to 450,000 g / mol, and the content of unsaturated double bonds is 97.5 to 99.5 wt%.

[0084] To further improve the mechanical and overall properties of diene rubbers, preferably, diene rubbers include, but are not limited to, natural rubber and / or polyisoprene rubber.

[0085] In a preferred embodiment, the BET specific surface area of ​​the silica is 170–190 m². 2 / g, pH value 6.2–6.8; BET specific surface area of ​​carbon black is 100–120m². 2 / g, DBP value (oil absorption value of carbon black) is 100-150cm 3 / 100g. Compared to other ranges, limiting the BET specific surface area and pH value of silica, as well as the BET specific surface area and DBP value of carbon black, to the above ranges is beneficial to improving the dispersibility of silica and carbon black and their interfacial bonding with the rubber matrix, thereby facilitating the better performance of the reinforcing effect of fillers.

[0086] To further improve the dispersibility of silica and enhance the interfacial bonding between silica and the matrix rubber, in a preferred embodiment, the coupling agent is a silane coupling agent. The silane coupling agent used in this application can be one or more commonly used in the art. Specifically, the silane coupling agent used in this application can be one or more of the following: γ-methacryloyloxypropyltriethoxysilane, and KBE-503, a product of Shin-Etsu Chemical Co., Ltd. of Japan.

[0087] To improve the efficiency and controllability of vulcanization and promote the formation of a more uniform and dense cross-linked network, in a preferred embodiment, the vulcanization accelerator includes, but is not limited to, one or more of N-cyclohexyl-2-benzothiazole sulfenamide (accelerator CZ), N-tert-butyl-2-benzothiazole sulfenamide (accelerator NS), and dibenzothiazole disulfide (accelerator DM).

[0088] The vulcanizing agent used in this application may be any type commonly used in the art. In a preferred embodiment, the vulcanizing agent is sulfur. Compared to other types, using sulfur as the vulcanizing agent is beneficial for improving the efficiency and controllability of vulcanization, and promotes the formation of a more uniform and dense cross-linked network.

[0089] In a preferred embodiment, the tread rubber composition further includes functional additives. Introducing functional additives into the tread rubber composition improves both the processability of the composition and the overall performance of the resulting tread rubber, including its wear resistance, wet skid resistance, and anti-aging properties.

[0090] To further improve the processability of the tread rubber composition and to further improve the overall properties of the tread rubber, such as wear resistance, wet skid resistance, and anti-aging properties, the functional additives are preferably 30 to 140 parts by weight, more preferably 40 to 69.5 parts by weight.

[0091] In a preferred embodiment, the functional additives include one or more of the following: anti-slip resin, bio-based plasticizer, zinc oxide, stearic acid, and antioxidant. The introduction of the anti-slip resin helps to increase the coefficient of friction of the tread rubber in wet environments, enhancing its anti-slip performance; the introduction of the bio-based plasticizer helps to improve the flexibility and environmental friendliness of the tread rubber; the introduction of zinc oxide helps to promote vulcanization and improve the thermal stability of the tread rubber; the introduction of stearic acid helps to improve the processability and stability of the tread rubber composition; and the introduction of the antioxidant helps to improve the anti-aging properties of the tread rubber.

[0092] To further improve the processability of the tread rubber composition and to further improve the overall performance of the tread rubber, such as wear resistance, anti-skid properties, and anti-aging properties, the functional additives preferably include, by weight: 5-80 parts of anti-skid resin, 5-30 parts of bio-based plasticizer, 0.5-10 parts of zinc oxide, 0.2-10 parts of stearic acid, and 1-10 parts of antioxidant.

[0093] To further improve the processability of the tread rubber composition and to further improve the overall properties of the tread rubber, such as wear resistance, anti-skid performance, and anti-aging performance, more preferably, the functional additives include, by weight: 10-40 parts of anti-skid resin, 5-15 parts of bio-based plasticizer, 1-6 parts of zinc oxide, 1-5 parts of stearic acid, and 0.5-3.5 parts of antioxidant.

[0094] To further improve the anti-slip properties of the tread rubber, in a preferred embodiment, the anti-slip resin includes, but is not limited to, dicyclopentadiene resin and / or a copolymer of C5 petroleum resin and C9 petroleum resin.

[0095] To further improve the flexibility and environmental friendliness of tire tread rubber, in a preferred embodiment, bio-based plasticizers include, but are not limited to, one or more of soybean oil, rapeseed oil, and epoxidized soybean oil.

[0096] To further improve the anti-aging properties of the tread rubber, in a preferred embodiment, the antioxidant includes, but is not limited to, antioxidant 4020 (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine) and / or antioxidant RD (2,2,4-trimethyl-1,2-dihydroquinoline polymer).

[0097] The second aspect of this application also provides a tread rubber, which is obtained by mixing and vulcanizing the tread rubber composition provided in this application. The tread rubber provided in this application uses a specific type of modified solution-polymerized styrene-butadiene rubber (SBR) as the core functional component, significantly improving the compatibility of each component in the tread rubber composition, thereby effectively leveraging the synergistic effect of each component and significantly improving the dispersibility of the filler and its interfacial interaction with the rubber matrix. By introducing modified SBR containing polar groups (such as hydroxyl, epoxy, anhydride, and silane groups), the tread rubber can form weak hydrogen bonds with water molecules on wet surfaces, thereby enhancing the grip of the tread rubber and improving its anti-slip ability. The tread rubber obtained from the tread rubber composition provided in this application has good structural stability, high-temperature grip performance, wear resistance, and anti-slip performance, meeting the requirements of racing tires for high-performance tread rubber.

[0098] The third aspect of this application also provides a method for preparing the above-mentioned tread rubber provided in this application. The preparation method includes: step S1, mixing modified solution-polymerized styrene-butadiene rubber, first solution-polymerized styrene-butadiene rubber, diene rubber, silica, carbon black and coupling agent to obtain masterbatch; step S2, mixing masterbatch, vulcanization accelerator and vulcanizing agent to obtain compound; step S3, vulcanizing compound to obtain tread rubber.

[0099] In step S1 of the above preparation method, modified solution-polymerized styrene-butadiene rubber (SBR), diene rubber, silica, carbon black, and coupling agent are mixed to fully utilize the effect of modified SBR, improve filler dispersibility, and enhance the interfacial bonding between the filler and the rubber matrix, resulting in a masterbatch. In step S2, a vulcanization accelerator and sulfur are added and mixed with the masterbatch a second time to obtain a compound, while inhibiting early crosslinking to ensure that the subsequent vulcanization reaction proceeds controllably in a stable system. In step S3, the compound is vulcanized to promote the formation of a dense and stable three-dimensional crosslinked network, resulting in tread rubber. Compared with other methods, this preparation method can effectively overcome the problems of poor filler dispersion, high risk of scorching, and large performance fluctuations in traditional methods, thereby significantly improving the structural stability, high-temperature grip, wear resistance, and wet skid resistance of the tread rubber.

[0100] In order to further improve the overall performance of the obtained tread rubber, such as wear resistance, wet skid resistance and aging resistance, in a preferred embodiment, functional additives are also introduced during the mixing process in step S1.

[0101] In order to improve the efficiency and effect of mixing, further improve the dispersibility of each component, and enhance the interfacial interaction between the rubber matrix and the filler, in a preferred embodiment, the mixing time in step S1 is 6 to 22 minutes; preferably, stirring is carried out during the mixing process in step S1, and the stirring rate is 60 to 85 rpm.

[0102] In a preferred embodiment, step S1 involves debinding after mixing, with the debinding temperature being 140–148°C. Compared to other ranges, limiting the debinding temperature to this range is beneficial for strengthening the interfacial interaction between the rubber matrix and the filler, and also helps to suppress localized vulcanization and scorching of the rubber compound caused by excessively high temperatures.

[0103] To improve the efficiency and effectiveness of mixing, in a preferred embodiment, the mixing temperature in step S2 is 45-65°C and the time is 8-10 minutes.

[0104] In a preferred embodiment, in step S3, the vulcanization temperature is 150–175°C, the pressure is 5–8 MPa, and the time is 8–20 min. The vulcanization temperature, pressure, and time include, but are not limited to, the above ranges. Limiting them to these ranges is beneficial for improving the efficiency and controllability of the vulcanization process, and promotes the formation of a more uniform and dense cross-linked network.

[0105] The fourth aspect of this application also provides the above-mentioned tread rubber composition provided in this application, or the application of the above-mentioned tread rubber provided in this application in racing tires. The above-mentioned tread rubber composition provided in this application uses a specific type of modified solution-polymerized styrene-butadiene rubber as the core functional component, which significantly improves the compatibility of each component in the tread rubber composition, thereby effectively exerting the synergistic effect of each component and significantly improving the dispersibility of the filler and its interfacial interaction with the rubber matrix. The tread rubber made using the above-mentioned tread rubber composition has good structural stability, high-temperature grip performance, wear resistance and wet skid resistance. When it is used as tread rubber in racing tires, it can make the loss factor (tanδ) in the high-temperature zone (40-80℃) show an increasing trend and tend to stabilize while maintaining the appropriate glass transition temperature of the hot melt tread rubber. This allows the tread rubber to maintain excellent grip performance in high-temperature environments (60-110℃), while also meeting the core requirements of racing tires for high-temperature melt processing and high elasticity after cooling.

[0106] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0107] Preparation Example

[0108] (I) Hydroxyl-modified solution-polymerized styrene-butadiene rubber (OH-SSBR)

[0109] The preparation method of hydroxyl-modified solution-polymerized styrene-butadiene rubber (SSBR, number average molecular weight of 186,800 g / mol) is as follows: Solution-polymerized styrene-butadiene rubber (SSBR, number average molecular weight of 186,800 g / mol) is added to a three-necked flask and vacuum-treated at 60°C for 3 hours; toluene is added and heated to 80°C to fully dissolve the SSBR, with a toluene volume to SSBR weight ratio of 11 mL:1 g; then 2-mercaptoethanol is added, with a 2-mercaptoethanol to SSBR weight ratio of 1:10, and stirring continues at 80°C for 30 minutes; finally, the initiator dodecanoyl peroxide (LP) is added. 2-Mercaptoethanol was reacted with SSBR via a mercapto-olefin click chemistry reaction. The initiator accounted for 1.16 wt% of the SSBR by weight. The mercapto-olefin click chemistry reaction was carried out at 80 °C for 3 h. After the reaction, ethanol precipitation and washing were performed sequentially three times. The resulting product was then vacuum dried at 60 °C to constant weight to obtain hydroxyl-modified solution-polymerized styrene-butadiene rubber (OH-SSBR). The number-average molecular weight of the prepared OH-SSBR was 195,700 g / mol, and the glass transition temperature was -53.21 °C. The content of styrene is 1.62 wt%, and the content of the corresponding styrene segments is 31.0 wt%.

[0110] (II) Epoxidation modified solution polystyrene-butadiene rubber (E-SSBR)

[0111] The preparation method of epoxidized solution-polymerized styrene-butadiene rubber (SSBR, number average molecular weight of 186,800 g / mol) is as follows: SSBR is added to a three-necked flask, and the mixture is evacuated at 50°C for 2 hours, followed by nitrogen purging. Toluene is added, and the mixture is heated to 60°C and stirred thoroughly at a stirring rate of 200 r / min until the SSBR is completely dissolved. The volume ratio of toluene to the weight of SSBR is 10 mL:1 g. Formic acid is then added, with a weight ratio of SSBR to formic acid of 1:9, and the mixture is stirred at 60°C. The mixture was stirred for 20 min; then hydrogen peroxide was added as an oxidant to induce an epoxidation reaction between formic acid and SSBR. The weight ratio of SSBR to hydrogen peroxide was 1:7. The epoxidation reaction was carried out at 60 °C for 4.5 h. After the reaction, ethanol coagulation and washing were performed sequentially, repeated three times. The resulting product was vacuum dried at 50 °C to constant weight to obtain epoxidized solution-polymerized styrene-butadiene rubber (E-SSBR). The number-average molecular weight of the prepared E-SSBR was 195,800 g / mol, and the glass transition temperature was -45.12 °C. The content of styrene is 2.4 wt%, and the content of the corresponding styrene segment is 32.4 wt%.

[0112] (III) Maleic anhydride modified solution-polymerized styrene-butadiene rubber (M-SSBR)

[0113] The preparation method of maleic anhydride-modified solution-polymerized styrene-butadiene rubber (SSBR, number-average molecular weight of 201,000 g / mol), maleic anhydride, and toluene are added to a three-necked flask under nitrogen protection. The weight ratio of maleic anhydride to SSBR is 0.15:1, and the volume ratio of toluene to SSBR is 10 mL:1 g. After the raw materials are fully dissolved, the initiator dodecanoyl peroxide (LPO) is added to induce an addition reaction between maleic anhydride and SSBR. The weight ratio of initiator to SSBR is 0.15:100. The addition reaction is carried out at 130℃ for 4.5 h. After the reaction is completed, the mixture is distilled under reduced pressure to obtain maleic anhydride-modified solution-polymerized styrene-butadiene rubber (M-SSBR). The obtained M-SSBR has a number-average relative molecular mass of 215,000 g / mol and a glass transition temperature of -54.20℃. The content of styrene is 2.5 wt%, and the content of the corresponding styrene segments is 31.2 wt%.

[0114] (IV) Silanized modified solution-polymerized styrene-butadiene rubber (Si-SSBR)

[0115] The preparation method of silanized modified solution-polymerized styrene-butadiene rubber (SSBR, number average molecular weight of 215,600 g / mol) is as follows: SSBR is added to a three-necked flask, and the flask is subjected to vacuum treatment at 60°C for 2 hours, followed by nitrogen purging. Toluene is added, with a volume ratio of toluene to SSBR of 20 mL: 1 g, and the mixture is heated to 80°C and stirred thoroughly at a stirring rate of 200 r / min until the SSBR is completely dissolved. Subsequently, 3-mercaptotripropoxysilane and dodecanoyl peroxide (LPO) are added, allowing the 3-mercaptotripropoxysilane to react with the SSBR. A mercapto-alkene click chemistry reaction was performed, in which the weight ratio of 3-mercaptotripropoxysilane to SSBR was 8:100, and the weight percentage of LPO in SSBR was 1.2 wt%. The mercapto-alkene click chemistry reaction was carried out at 80 °C for 2.5 h. After the reaction, ethanol coagulation and washing were performed sequentially, repeated three times. The resulting product was vacuum dried at 60 °C to constant weight to obtain silanized modified solution-polymerized styrene-butadiene rubber (Si-SSBR). The number-average relative molecular mass of the prepared Si-SSBR was 216,700 g / mol, and the glass transition temperature was -54.37 °C. The content of styrene is 2.56 wt%, and the content of the corresponding styrene segments is 28.67 wt%.

[0116] (V) Epoxidation-silanization dual-modified solution-polymerized styrene-butadiene rubber (E-Si-SSBR)

[0117] The preparation method of epoxidation-silanization dual-modified solution-polymerized styrene-butadiene rubber (SSBR, number average molecular weight of 226,000 g / mol) includes the following steps: Step N1, solution-polymerized styrene-butadiene rubber (SSBR, number average molecular weight of 226,000 g / mol) is added to a three-necked flask, and vacuum treatment is carried out at 50°C for 2 h, followed by nitrogen purging; toluene is added, with a toluene volume to SSBR weight ratio of 20 mL: 1 g, and the mixture is heated to 60°C and stirred thoroughly at a stirring rate of 200 r / min until the SSBR is completely dissolved; then formic acid is added, with a formic acid to SSBR weight ratio of 9:1, and stirring is continued at this temperature for 20 min; then hydrogen peroxide is added to cause an epoxidation reaction between formic acid and SSBR, with a hydrogen peroxide to SSBR weight ratio of 7:1, and the epoxidation reaction temperature is 60°C for 4.5 h; after the reaction, ethanol coagulation and washing are performed sequentially, repeated three times, and the obtained product is vacuum-treated at 50°C. The product was dried to constant weight to obtain an epoxidized intermediate. In step N2, the epoxidized intermediate, 3-mercaptotripropoxysilane, dodecanoyl peroxide (LPO), and toluene were mixed, and a mercapto-olefin click chemical reaction was carried out between the 3-mercaptotripropoxysilane and the epoxidized intermediate. The weight ratio of the epoxidized intermediate, 3-mercaptotripropoxysilane, and LPO was 100:15:0.5, the volume ratio of toluene to the weight of the epoxidized intermediate was 20 mL:1 g, and the temperature of the mercapto-olefin click chemical reaction was 80 °C for 3.5 h. After the reaction, ethanol coagulation and washing were performed sequentially, repeated three times. The resulting product was vacuum dried at 55 °C to constant weight to obtain epoxidized-silanized double-modified solution-polymerized styrene-butadiene rubber (E-Si-SSBR). The number-average relative molecular mass of the prepared E-Si-SSBR was 245,000 g / mol, and the glass transition temperature was -56.80 °C. The content was 2.23 wt%. The content of styrene was 2.98 wt%, and the content of the corresponding styrene segments was 27.64 wt%.

[0118] The modified solution-polymerized styrene-butadiene rubber (modified SSBR) in Examples 1 to 23 and Comparative Examples 1 to 10 below were prepared using OH-SSBR, E-SSBR, M-SSBR, Si-SSBR and E-Si-SSBR prepared in the above preparation examples, respectively.

[0119] Example 1

[0120] A method for preparing tire tread rubber specifically includes the following steps:

[0121] (1) Prepare the raw materials for each component used to prepare the tread rubber according to Table 1;

[0122] (2) Set the rotor speed of the internal mixer to 70 rpm; add modified SSBR, solution-polymerized styrene-butadiene rubber, natural rubber, two-thirds by weight of silica, carbon black, silane coupling agent, soybean oil, stearic acid and antioxidant to the internal mixer, mix for 8 minutes and then discharge the rubber to obtain the first masterbatch.

[0123] (3) Set the rotor speed of the internal mixer to 70 rpm; add the first masterbatch obtained in step (2) and the remaining one-third of the weight of silica to the internal mixer, mix for 8 minutes and then discharge the rubber to obtain the second masterbatch;

[0124] (4) Set the rotor speed of the internal mixer to 60 rpm; add the second masterbatch and zinc oxide obtained in step (3) to the internal mixer, mix for 6 minutes and then discharge the masterbatch to obtain the third masterbatch;

[0125] (5) The third masterbatch, vulcanization accelerator and sulfur obtained in step (4) are mixed in a two-roll mill. The roller temperature of the two-roll mill is 50°C and the mixing time is 10 min to obtain the mixed rubber.

[0126] (6) The compound obtained in step (5) is vulcanized at 175℃ and 6MPa for 9 minutes to obtain tread rubber.

[0127] Examples 2 to 23

[0128] The difference from Example 1 is that in step (1), the amount and type of each component raw material used to prepare the tread rubber are different from those in Example 1, as shown in Tables 1, 2 and 3; the remaining steps are the same as in Example 1.

[0129] In Examples 1 to 23, the types and amounts of raw materials used to prepare the tread rubber are shown in Tables 1, 2 and 3.

[0130] Table 1

[0131]

[0132] Table 2

[0133]

[0134] Table 3

[0135]

[0136] The sources of the raw materials in Tables 1, 2 and 3 above are as follows: (1) Solution polystyrene-butadiene rubber (SSBR): Yanshan Petrochemical, SSBR2055M product, cis-1,4 structure content ≥98%; (2) Natural rubber: the main component is cis-1,4-polyisoprene, product model is TSR 20, initial plasticity value is 35, plasticity retention rate is 72%; (3) Silica: Aidalong Chemical Co., Ltd., HDS-180 product, BET specific surface area is 178m². 2 / g, pH value is 7.0; (4) Carbon black: Jiangxi Black Cat Carbon Black Co., Ltd., model is N220, BET specific surface area is 118m 2 / g; (5) Silane coupling agent: Shin-Etsu Chemical Co., Ltd., Japan, KBE-503; (6) Anti-slip resin: ExxonMobil, Escorez 5300 product, softening point is 105℃; (7) Soybean oil: Jinlongyu product; (8) Zinc oxide: Hengshan Zinc Industry Co., Ltd., Hengshan indirect zinc oxide; (9) Stearic acid: Wilmar Stearic Acid 1865; (10) Antioxidant: Saint-Au Chemical Antioxidant, Sirantox 6PPD; (11) Vulcanization accelerator CZ: Shandong Shangshun Chemical.

[0137] Example 24

[0138] The difference from Example 1 is that the type of HO-SSBR used in step (1) is different from that in Example 1. Specifically, the number-average relative molecular mass of the HO-SSBR used in Example 24 is 200,000 g / mol, and the glass transition temperature is -51.6℃. The content of styrene is 3.0 wt%, and the content of the corresponding styrene segment is 32.1 wt%; the remaining steps are the same as in Example 1.

[0139] Example 25

[0140] The difference from Example 1 is that the type of HO-SSBR used in step (1) is different from that in Example 1. Specifically, the number-average relative molecular mass of the HO-SSBR used in Example 25 is 130,000 g / mol, and the glass transition temperature is -55.6℃. The content of 0.5 wt% and the content of the corresponding styrene segment is 23.1 wt%; the remaining steps are the same as in Example 1.

[0141] Example 26

[0142] The difference from Example 2 is that the type of E-SSBR used in step (1) is different from that in Example 2. Specifically, the E-SSBR used in Example 26 has a number-average relative molecular mass of 190,000 g / mol and a glass transition temperature of -42.6℃. The content of 1 wt% is styrene, and the content of the corresponding styrene segment is 31.2 wt%; the remaining steps are the same as in Example 2.

[0143] Example 27

[0144] The difference from Example 2 is that the type of E-SSBR used in step (1) is different from that in Example 2. Specifically, the E-SSBR used in Example 27 has a number-average relative molecular mass of 150,000 g / mol and a glass transition temperature of -48.6 °C. The content of is 0.5 wt%, and the content of the corresponding styrene segment is 22.5 wt%; the remaining steps are the same as in Example 2.

[0145] Example 28

[0146] The difference from Example 3 is that the type of M-SSBR used in step (1) is different from that in Example 3. Specifically, the M-SSBR used in Example 28 has a number-average relative molecular mass of 220,000 g / mol and a glass transition temperature of -52.7℃. The content of styrene is 3.0 wt%, and the content of the corresponding styrene segment is 33 wt%; the remaining steps are the same as in Example 3.

[0147] Example 29

[0148] The difference from Example 3 is that the type of M-SSBR used in step (1) is different from that in Example 3. Specifically, the M-SSBR used in Example 29 has a number-average relative molecular mass of 160,000 g / mol and a glass transition temperature of -57.3℃. The content of 0.5 wt% and the content of the corresponding styrene segment is 24.7 wt%; the remaining steps are the same as in Example 3.

[0149] Example 30

[0150] The difference from Example 4 is that the type of Si-SSBR used in step (1) is different from that in Example 4. Specifically, the Si-SSBR used in Example 30 has a number-average relative molecular mass of 210,000 g / mol and a glass transition temperature of -57.0 °C. The content of 1 wt% is styrene, and the content of the corresponding styrene segment is 27.9 wt%; the remaining steps are the same as in Example 4.

[0151] Example 31

[0152] The difference from Example 4 is that the type of Si-SSBR used in step (1) is different from that in Example 4. Specifically, the Si-SSBR used in Example 31 has a number-average relative molecular mass of 170,000 g / mol and a glass transition temperature of -58.4℃. The content of is 0.5 wt%, and the content of the corresponding styrene segment is 22.4 wt%; the remaining steps are the same as in Example 4.

[0153] Example 32

[0154] The difference from Example 19 is that the type of E-Si-SSBR used in step (1) is different from that in Example 19. Specifically, the E-Si-SSBR used in Example 32 has a number-average relative molecular mass of 250,000 g / mol and a glass transition temperature of -55.8 °C. The content is 2.5 wt%. The content of is 2.0 wt%, and the content of the corresponding styrene segment is 28.7 wt%; the remaining steps are the same as in Example 19.

[0155] Example 33

[0156] The difference from Example 19 is that the type of E-Si-SSBR used in step (1) is different from that in Example 19. Specifically, the E-Si-SSBR used in Example 33 has a number-average relative molecular mass of 180,000 g / mol and a glass transition temperature of -59.1℃. The content is 0.5 wt%. The content of styrene is 1 wt%, and the content of the corresponding styrene segment is 21.9 wt%; the remaining steps are the same as in Example 19.

[0157] Comparative Examples 1 to 10

[0158] The difference from Example 1 is that in step (1), the amount and type of each component raw material used to prepare the tread rubber are different from those in Example 1, as shown in Table 4; the remaining steps are the same as in Example 1.

[0159] Table 4 shows the types and amounts of raw materials used to prepare the tread rubber in Comparative Examples 1 to 10.

[0160] Table 4

[0161]

[0162] The following performance tests were performed on the tread rubbers obtained from all the above embodiments and comparative examples of this application:

[0163] (1) Tensile strength and elongation at break: measured at 25℃ according to the method described in national standard GB / T528-2020;

[0164] (2) Dynamic mechanical properties: DMA temperature scanning test was used (strain 0.25%, frequency 10Hz, temperature range -60~80℃, heating rate 3℃ / min); the energy storage modulus G' at 20℃ was used to characterize the handling performance, and the larger the value of G'@20℃, the better the handling performance; tanδ at 0℃ was used to characterize the wet grip performance, and the larger the value of tanδ@0℃, the better the wet grip performance; tanδ at 20℃ was used to characterize the dry grip performance, and the larger the value of tanδ@20℃, the better the dry grip performance.

[0165] (3) High temperature wet grip performance: The grip performance of vulcanized rubber under high temperature was tested using the LAT-100 testing machine. LAT high temperature wet grip: the load was 75N, the test temperature was 25℃, 60℃ and 75℃ respectively, the slip angle was 15°, and the test speed was 0.6km / h; the larger the value of the friction coefficient μ, the better the grip performance.

[0166] For ease of comparison, the test results of Comparative Example 1 were used as the base index, with a value of 100 for all examples. The results obtained from the other examples and comparative examples were converted relative to the test results of Comparative Example 1, and test indices were calculated separately. The higher the test index, the better the corresponding performance compared to Comparative Example 1. The specific test results of Examples 1 to 33 are shown in Table 5, and the specific test results of Comparative Examples 1 to 10 are shown in Table 6.

[0167] Table 5

[0168]

[0169] Table 6

[0170]

[0171] Comparing Example 1 and Comparative Example 1, and referring to Tables 5 and 6, it can be seen that since hydroxyl-modified SSBR was not added to the raw materials of Comparative Example 1, its rubber system consisted only of natural rubber and solution-polymerized styrene-butadiene rubber. Therefore, the G'@20℃, tanδ@0℃, and tanδ@20℃ values ​​of Comparative Example 1 were all lower than those of Example 1, and the coefficient of friction μ values ​​of Comparative Example 1 at 25℃, 60℃, and 75℃ were all lower than those of Example 1. It can be seen that the handling performance, anti-slip performance on wet roads, and grip at high temperatures of Comparative Example 1 are significantly deteriorated compared with Example 1, and the safety and racing performance of the racing tires cannot be guaranteed.

[0172] Comparing Examples 1 to 8 of this application with Comparative Examples 1 to 4 and Comparative Examples 9 to 10, it can be seen that Examples 1 to 8 significantly improve the handling performance, wet grip performance, high-temperature grip performance and resistance to heat fade of racing tires due to the use of the specific type of modified SSBR described above in this application.

[0173] Although Comparative Examples 5 to 8 used the specific type of modified SSBR described above in this application, the amount used exceeded the maximum limit, therefore, the overall performance of the resulting tread rubber was still poor.

[0174] As can be seen from the above description, the embodiments of this application achieve the following technical effects:

[0175] The tread rubber composition provided in this application, with a specific type of modified solution-polymerized styrene-butadiene rubber (SBR) as the core functional component, significantly improves the compatibility of each component in the tread rubber composition, thereby effectively leveraging the synergistic effect of each component and significantly improving the dispersibility of the filler and its interfacial interaction with the rubber matrix. By introducing modified SBR containing polar groups, the tread rubber can form weak hydrogen bonds with water molecules on wet surfaces, thereby enhancing the grip of the tread rubber and improving its anti-skid ability. The tread rubber made from the tread rubber composition provided in this application has good structural stability, high-temperature grip performance, wear resistance, and anti-skid performance. When used as tread rubber in racing tires, it can maintain a suitable glass transition temperature for the hot-melt tread rubber while making the loss factor (tanδ) in the high-temperature zone show an increasing trend and tend to stabilize, thus enabling the tread rubber to maintain excellent grip performance in high-temperature environments, while also meeting the core requirements of racing tires for high-temperature melt processing and high elasticity after cooling.

[0176] It should be noted that the terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in a sequence other than those described herein.

[0177] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A tread rubber composition, characterized in that, By weight, the tread rubber composition comprises: 10-60 parts modified solution-polymerized styrene-butadiene rubber, 1-50 parts primary solution-polymerized styrene-butadiene rubber, 1-60 parts diene rubber, 10-120 parts silica, 5-40 parts carbon black, 0.1-20 parts coupling agent, 0.1-5 parts vulcanization accelerator, and 0.5-10 parts vulcanizing agent; The modified solution-polymerized styrene-butadiene rubber is selected from one or more of hydroxyl-modified solution-polymerized styrene-butadiene rubber, epoxidized solution-polymerized styrene-butadiene rubber, maleic anhydride-modified solution-polymerized styrene-butadiene rubber, silanized solution-polymerized styrene-butadiene rubber, and epoxidized-silanized dual-modified solution-polymerized styrene-butadiene rubber.

2. The tread rubber composition according to claim 1, characterized in that, By weight, the tread rubber composition comprises: 20-40 parts of the modified solution-polymerized styrene-butadiene rubber, 5-40 parts of the first solution-polymerized styrene-butadiene rubber, 10-60 parts of the diene rubber, 20-90 parts of the silica, 10-30 parts of the carbon black, 1-15 parts of the coupling agent, 0.5-1.5 parts of the vulcanization accelerator, and 1-3 parts of the vulcanizing agent.

3. The tread rubber composition according to claim 1 or 2, characterized in that, The hydroxyl-modified solution-polymerized styrene-butadiene rubber has the chemical formula shown in formula (I): (I); where x1 is an integer between 1800 and 2600, n1 is an integer between 10 and 50, and m1 is an integer between 540 and 630; and / or, The epoxidized solution-polymerized styrene-butadiene rubber has the chemical formula shown in formula (II): (II); where x2 is an integer between 2100 and 2600, n2 is an integer between 20 and 90, and m2 is an integer between 550 and 640; and / or, The maleic anhydride-modified solution-polymerized styrene-butadiene rubber has the chemical formula shown in formula (III): (III); where x3 is an integer between 2300 and 2950, ​​n3 is an integer between 10 and 50, and m3 is an integer between 560 and 700; and / or, The silanized modified solution-polymerized styrene-butadiene rubber has the chemical formula shown in formula (IV): (IV); where x4 is an integer between 2600 and 3050, n4 is an integer between 5 and 20, and m4 is an integer between 545 and 615; and / or, The epoxidized-silanized dual-modified solution-polymerized styrene-butadiene rubber has the chemical formula shown in formula (V): (V); where x5 is an integer between 2650 and 3440, n5 is an integer between 30 and 90, n6 is an integer between 12 and 25, and m5 is an integer between 575 and 675.

4. The tread rubber composition according to claim 3, characterized in that, The number-average relative molecular mass of the hydroxyl-modified solution-polymerized styrene-butadiene rubber is 180,000 to 200,000 g / mol; preferably, the glass transition temperature of the hydroxyl-modified solution-polymerized styrene-butadiene rubber is -54.4 to -51.6 °C; preferably, in the hydroxyl-modified solution-polymerized styrene-butadiene rubber, The content of styrene is 1.0–3.0 wt%, and the content of the corresponding styrene segment is 30–32 wt%; and / or, The number-average relative molecular mass of the epoxidized solution-polymerized styrene-butadiene rubber is 190,000 to 200,000 g / mol; preferably, the glass transition temperature of the epoxidized solution-polymerized styrene-butadiene rubber is -46.5 to -42.3 °C; preferably, in the epoxidized solution-polymerized styrene-butadiene rubber, The content of styrene is 1.0–3.0 wt%, and the content of the corresponding styrene segment is 31–33 wt%; and / or, The maleic anhydride-modified solution-polymerized styrene-butadiene rubber has a number-average relative molecular mass of 210,000 to 220,000 g / mol; preferably, the glass transition temperature of the maleic anhydride-modified solution-polymerized styrene-butadiene rubber is -55.5 to -52.7 °C; preferably, in the maleic anhydride-modified solution-polymerized styrene-butadiene rubber, The content of styrene is 1.0–3.0 wt%, and the content of the corresponding styrene segment is 29–33 wt%; and / or, The number-average relative molecular mass of the silanized modified solution-polymerized styrene-butadiene rubber is 210,000 to 220,000 g / mol; preferably, the glass transition temperature of the silanized modified solution-polymerized styrene-butadiene rubber is -57.0 to -54.0 °C; preferably, in the silanized modified solution-polymerized styrene-butadiene rubber, The content of styrene is 1.0–3.0 wt%, and the content of the corresponding styrene segment is 27–29 wt%; and / or, The number-average relative molecular mass of the epoxidized-silanized dual-modified solution-polymerized styrene-butadiene rubber is 230,000 to 250,000 g / mol; preferably, the glass transition temperature of the epoxidized-silanized dual-modified solution-polymerized styrene-butadiene rubber is -58.5 to -55.4 °C; preferably, in the epoxidized-silanized dual-modified solution-polymerized styrene-butadiene rubber, The content is 0.9–2.5 wt%. The content of styrene is 2.0–3.2 wt%, and the content of the corresponding styrene segments is 26–28 wt%.

5. The tread rubber composition according to claim 3 or 4, characterized in that, The preparation method of the hydroxyl-modified solution-polymerized styrene-butadiene rubber includes: under the action of an initiator, causing 2-mercaptoethanol to undergo a first mercapto-olefin click chemical reaction with a second solution-polymerized styrene-butadiene rubber to obtain the hydroxyl-modified solution-polymerized styrene-butadiene rubber; preferably, the weight ratio of 2-mercaptoethanol to the second solution-polymerized styrene-butadiene rubber is 1:(5-10); the initiator accounts for 0.1-2 wt% of the weight of the second solution-polymerized styrene-butadiene rubber; the initiator is selected from one or more of dodecanoyl peroxide, tert-butyl hydroperoxide, and azobisisobutyronitrile; preferably, the temperature of the first mercapto-olefin click chemical reaction is 80-95°C, and the time is 0.5-3.5 h; and / or, The method for preparing the epoxidized solution-polymerized styrene-butadiene rubber includes: under the action of an oxidant, formic acid and a second solution-polymerized styrene-butadiene rubber undergo a first epoxidation reaction to obtain the epoxidized solution-polymerized styrene-butadiene rubber; preferably, the weight ratio of the second solution-polymerized styrene-butadiene rubber to the formic acid is 1:(5-10); the weight ratio of the second solution-polymerized styrene-butadiene rubber to the oxidant is 1:(3-10); the oxidant is selected from one or more of hydrogen peroxide, tert-butyl hydroperoxide, and cumene peroxide; preferably, the temperature of the first epoxidation reaction is 45-80°C, and the time is 1-4.5 h; and / or, The preparation method of the maleic anhydride-modified solution-polymerized styrene-butadiene rubber includes: under the action of an initiator, maleic anhydride undergoes an addition reaction with a second solution-polymerized styrene-butadiene rubber to obtain the maleic anhydride-modified solution-polymerized styrene-butadiene rubber; preferably, the weight percentage of maleic anhydride in the second solution-polymerized styrene-butadiene rubber is 5-20 wt%; the weight percentage of the initiator in the second solution-polymerized styrene-butadiene rubber is 0.1-2 wt%; preferably, the temperature of the addition reaction is 120-180°C, and the time is 2-6 h; and / or, The preparation method of the silanized modified solution-polymerized styrene-butadiene rubber includes: under the action of an initiator, causing 3-mercaptotripropoxysilane to undergo a second mercapto-olefin click chemical reaction with a second solution-polymerized styrene-butadiene rubber to obtain the silanized modified solution-polymerized styrene-butadiene rubber; preferably, the weight ratio of the 3-mercaptotripropoxysilane to the second solution-polymerized styrene-butadiene rubber is (1-10):100; the initiator accounts for 0.1-2 wt% of the weight of the second solution-polymerized styrene-butadiene rubber; preferably, the temperature of the second mercapto-olefin click chemical reaction is 80-100°C, and the time is 0.5-2.5 h; and / or, The preparation method of the epoxidized-silanized dual-modified solution-polymerized styrene-butadiene rubber includes: under the action of an oxidant, formic acid and a second solution-polymerized styrene-butadiene rubber undergo a second epoxidation reaction to obtain an epoxidized modified solution-polymerized styrene-butadiene rubber intermediate; under the action of an initiator, the epoxidized modified solution-polymerized styrene-butadiene rubber intermediate undergoes a third mercapto-olefin click chemical reaction with 3-mercaptotripropoxysilane to obtain the epoxidized-silanized dual-modified solution-polymerized styrene-butadiene rubber; preferably, the weight ratio of the second solution-polymerized styrene-butadiene rubber to the formic acid is 1:(5-10); the weight ratio of the second solution-polymerized styrene-butadiene rubber to the oxidant is... The ratio of the oxidant to the epoxidized solution-polymerized styrene-butadiene rubber intermediate is 1:(3-10); the oxidant is selected from one or more of hydrogen peroxide, tert-butyl hydrogen peroxide, and cumene peroxide; the temperature of the second epoxidation reaction is 45-80°C, and the time is 1-4.5 h; preferably, the weight ratio of the 3-mercaptotripropoxysilane to the epoxidized solution-polymerized styrene-butadiene rubber intermediate is (15-25):100; the initiator accounts for 0.5-2.5 wt% of the weight of the epoxidized solution-polymerized styrene-butadiene rubber intermediate; the temperature of the third mercapto-olefin click chemistry reaction is 80-110°C, and the time is 1-3.5 h.

6. The tread rubber composition according to any one of claims 1 to 5, characterized in that, The first solution-polymerized styrene-butadiene rubber has a weight-average molecular weight of 250,000 to 350,000 g / mol; and / or, The diene rubber has a weight-average molecular weight of 300,000 to 450,000 g / mol and an unsaturated double bond content of 97.5 to 99.5 wt%; preferably, the diene rubber is selected from natural rubber and / or polyisoprene rubber; and / or, The coupling agent is a silane coupling agent; and / or, The vulcanization accelerator is selected from one or more of N-cyclohexyl-2-benzothiazole sulfenamide, N-tert-butyl-2-benzothiazole sulfenamide, and dibenzothiazole disulfide; and / or The vulcanizing agent is sulfur; and / or, The tread rubber composition further includes functional additives; preferably, the functional additives are in the form of 30 to 140 parts by weight; preferably, the functional additives include one or more of the following: anti-slip resin, bio-based plasticizer, zinc oxide, stearic acid, and antioxidant; more preferably, by weight, the functional additives include: 5 to 80 parts of the anti-slip resin, 5 to 30 parts of the bio-based plasticizer, 0.5 to 10 parts of the zinc oxide, 0.2 to 10 parts of the stearic acid, and 1 to 10 parts of the antioxidant.

7. A tread rubber, characterized in that, The tread rubber is obtained by mixing and vulcanizing the tread rubber composition according to any one of claims 1 to 6.

8. A method for preparing the tread rubber according to claim 7, characterized in that, The preparation method includes: Step S1: The modified solution-polymerized styrene-butadiene rubber, the first solution-polymerized styrene-butadiene rubber, the diene rubber, the silica, the carbon black and the coupling agent are mixed to obtain the masterbatch. Step S2: The masterbatch, vulcanization accelerator and vulcanizing agent are mixed to obtain a compound rubber; Step S3: The compound rubber is vulcanized to obtain the tread rubber.

9. The method for preparing tread rubber according to claim 8, characterized in that, Functional additives are also introduced during the mixing process in step S1. Preferably, the mixing time in step S1 is 6 to 22 minutes; Preferably, stirring is performed during the mixing process in step S1; more preferably, the stirring rate is 60-85 rpm. Preferably, step S1 further includes debinding after mixing; more preferably, the debinding temperature is 140–148°C. Preferably, the mixing temperature in step S2 is 45-65°C and the time is 8-10 minutes. Preferably, in step S3, the vulcanization temperature is 150–175°C, the pressure is 5–8 MPa, and the time is 8–20 min.

10. The use of a tread rubber composition according to any one of claims 1 to 6, or the tread rubber according to claim 7, in a racing tire.

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