Low-hysteresis and high-fatigue-resistance tread rubber composition, mixing method thereof and tire

Abstract

The invention relates to a low-hysteresis and high-fatigue-resistance tread rubber composition, a mixing method thereof and a tire, the composition comprises raw rubber, white carbon black, nitrogen-containing polysulfide, a silane coupling agent and a vulcanization bag, the general chemical formula of the nitrogen-containing polysulfide is # imgabs0 #, x is an integer of 2-6; r1 is an aromatic ring structure molecule; r2 is a nitrogen atom-containing aliphatic chain molecule or aromatic ring molecule, and the aliphatic chain molecule is selected from a linear aliphatic chain molecule or a branched aliphatic chain molecule. The nitrogen-containing polysulfide is added during rubber mixing, so that nitrogen atoms are conveniently introduced into a rubber molecular chain, in-situ functionalization of the rubber is realized, redundant steps are not needed, and popularization and application in industry are facilitated. The introduced nitrogen atoms can generate hydrogen-bond interaction with white carbon black, so that the dispersion of the nitrogen atoms in a rubber matrix is improved, the silanization reaction is promoted, and the interface interaction is enhanced, so that the rubber has obviously lower hysteresis loss and higher fatigue resistance.

Description

Technical Field

[0001] The present invention relates to the field of tire manufacturing, and particularly to a low hysteresis and high fatigue-resistant tread rubber composition, its mixing method, and a tire. Background Art

[0002] As a reinforcing filler for rubber, silica can significantly improve the mechanical strength, wear resistance, modulus and other properties of rubber materials. However, due to the small particle size, high surface energy of silica, and the large number of polar silanol groups on the silica surface, the compatibility between silica and non-polar rubber is extremely poor, resulting in serious aggregation in the composite material and weak interfacial interaction with the rubber matrix. In order to maximize the potential of silica in the field of rubber tires, improving the dispersion of silica in the rubber matrix and enhancing the interfacial interaction between silica and the rubber matrix are the keys to affecting the comprehensive performance of the tread rubber composition.

[0003] Currently, there are mainly three methods to improve the interfacial interaction between rubber and silica: (1) Pretreatment and modification of silica: Modify silica by means of physical shielding or chemical action to enhance the compatibility between silica and rubber molecular chains. For example, Patent [CN 115536913 A] discloses that N-(1,3-dimethyl)butyl-N'-phenyl-p-phenylenediamine, a p-phenylenediamine derivative, pre-modifies silica to improve its compatibility with rubber, thereby improving the modulus and anti-aging properties of the rubber compound. Patent [CN116948428A] modifies nano-silica with silane coupling agent and sorbitan fatty acid ester, and the prepared tread rubber has improved wear resistance and low rolling resistance. However, the method of pretreating silica will destroy the aggregated structure of silica, require additional steps, and the process is cumbersome. (2) Development of functionalized rubber: Introduce functional groups that interact with silica into the rubber molecular chain to enhance the affinity between rubber and silica. For example: Introduce functional monomers containing nitrogen or siloxane during rubber synthesis for copolymerization, but this method relies on special functional monomers and initiators, and this strategy cannot be adopted for common natural rubber and cis-butadiene rubber; in addition, post-functionalize commercial olefin rubbers, but this process requires organic solvents and will generate gels. (3) Adding modifiers during the in-situ mixing process of rubber and silica, and realizing interfacial coupling based on the interaction between the modifier and silica and rubber respectively, which is the simplest and easiest to industrialize method. In the tire industry, the most widely used are sulfur-containing silane coupling agents such as Si69 and Si75. The modification principle is that the polysulfide bonds in the molecule react with rubber, and the ethoxysilyl groups in the molecule undergo condensation reaction with the silanol groups on the silica surface, thereby playing an interfacial coupling role. However, the reaction activity between silane coupling agent and silica is low, and a large amount of silane coupling agent needs to be added to improve the modification effect. However, excessive addition of silane coupling agent will cause self-condensation of the alkoxysilyl groups of the molecule itself or intermolecular condensation to form a multi-molecular layer on the silica surface, and the interfacial structure is difficult to control, and the performance cannot be further improved.

[0004] In 2013, Pyun et al. used molten sulfur as a reaction medium and 1,3 - diisopropylbenzene (DIB) for copolymerization, successfully synthesizing a stable sulfur - containing polymer, and this process was named "inverse vulcanization" (Nature Chemistry, 2013, 5: 518 - 524). Subsequently, researchers copolymerized sulfur with various unsaturated olefin monomers to adjust the properties of sulfur - containing polymers, which showed great application value in fields such as heavy metal adsorption, electrode materials, and infrared lenses. The polysulfide molecules contain a large number of polysulfide bonds and can react with rubber; when functional groups that can interact with fillers are introduced into polysulfide, polysulfide can be used as an interface modifier for rubber - filler. For example, amino - polysulfide is obtained by copolymerizing elemental sulfur and m - phenylenediamine. Based on the interactions such as the formation of amide bonds and ionic bonds between the amino groups in amino - polysulfide and the carboxyl groups on the surface of carbon black, it can be used as an interface modifier for carbon black / natural rubber composites to improve the dispersion of carbon black and the interfacial bonding with rubber. For the relevant prior art, please refer to: Amino - polysulfide modified carbon black / rubber composite material and its preparation method disclosed in Chinese Patent (ZL 202210056309.7), and the journal paper "Chemistry of Materials, 2023, 35, 764 - 772". However, in the applications disclosed in the existing rubber field, nitrogen - containing polysulfide is only used to modify the carbon black filler reinforcement system, and there is no report on the influence and application of nitrogen - containing polysulfide on the silica filler reinforcement system. Summary of the Invention

[0005] The present invention aims to solve various problems existing in the prior art methods such as silica pretreatment modification, development of functionalized rubber, and in - situ addition of interface modifiers due to the difficulty of uniform dispersion of silica in the rubber matrix and the weak interfacial interaction force between silica and the rubber matrix, and provides a nitrogen - containing polysulfide modified silica - filled tread rubber composite material and its preparation method.

[0006] To achieve the above - mentioned purpose, on the one hand, the present invention provides a low - hysteresis and high - fatigue - resistant tread rubber composition, which includes raw rubber, silica, nitrogen - containing polysulfide, silane coupling agent, and vulcanization package;

[0007] The chemical general formula of the nitrogen - containing polysulfide is:

[0008] where x is an integer from 2 to 6; R1 is an aromatic ring - structured molecule; R2 is a fatty - chain molecule or an aromatic - ring molecule containing a nitrogen atom, and the fatty - chain molecule is selected from a linear fatty - chain molecule or a branched fatty - chain molecule;

[0009] The dosage of the main components in the rubber composition is as follows: the weight of the silica is 40-100 wt% of the raw rubber, the weight of the silane coupling agent is 4-10 wt% of the silica, and the weight of the nitrogen-containing polysulfide is 0.1-0.5 wt% of the raw rubber.

[0010] The inventors found that when the weight of the nitrogen-containing polysulfide with the above structure is limited to 0.1-0.5 wt% of the raw rubber, in-situ functionalized rubber can be achieved by grafting rubber during the mixing process through the polysulfide chains. Through a large number of experiments, it was found that when the dosage of the nitrogen-containing polysulfide is less than 0.1 wt%, the degree of in-situ functionalization of the rubber is low, the hydrogen bond interaction with the silanol groups on the silica surface is weakened, the promotion effect on the silanization reaction is weakened, and the interfacial force between the silica and the rubber matrix cannot be improved; when the dosage is higher than 0.5 wt% of the raw rubber, the polysulfide chains contribute to the crosslinking density, the elongation at break of the rubber decreases, and the fatigue resistance becomes poor.

[0011] The inventors also unexpectedly found that after the nitrogen-containing polysulfide containing the above formula is grafted onto the rubber molecular chain, it can promote the silanization reaction, reduce the addition amount of the silane coupling agent, and use less silane coupling agent than that used in the traditional rubber mixing process. Therefore, the requirement for the dosage of the silane coupling agent in the process of this application is relatively less than that of the traditional process, and the cost is lower.

[0012] The raw rubber preferably comprises a diene rubber. The inventors found that at high temperature, a large number of sulfur free radicals generated by the nitrogen-containing polysulfide with the above formula will undergo an addition reaction with the double bonds in the diene rubber, grafting the nitrogen atoms onto the rubber molecular chain to achieve in-situ functionalized rubber. In actual production, the raw rubber can also be selected from one or more of diene rubber, styrene-butadiene rubber, natural rubber and cis-1,4-polybutadiene rubber.

[0013] Preferably, the composition of the present invention further comprises at least one of microcrystalline wax, anti-aging agent and scorch retarder. Among them, the anti-aging agent is 6PPD, and the microcrystalline wax is used as a processing aid. It should be noted here that the vulcanization package, microcrystalline wax, anti-aging agent and scorch retarder are all commonly used rubber additive raw materials in the rubber industry. According to the type of raw rubber, the dosage and type will vary, and their specific selection belongs to conventional technology. Preferably, the vulcanization package is selected from at least one of accelerator CZ, accelerator DPG and sulfur. Further, the composition further comprises an activator, and the activator is selected from at least one of zinc oxide and stearic acid.

[0014] According to another aspect of the present invention, the present invention also provides a mixing method for a low hysteresis and high fatigue resistance tread rubber composition, which comprises the following steps:

[0015] Step S1: Add raw rubber, silica, silane coupling agent, and nitrogen-containing polysulfide into a torque rheometer for mixing. The rotor speed is 20 - 40 rpm, and the mixing is carried out for 3 - 10 minutes. Discharge the rubber at 50 - 70 °C to obtain the first-stage mixed rubber, which is parked and cooled at room temperature for standby. Among them: If the first-stage mixing time is less than 3 minutes, the raw rubber, silica, and other additive components cannot be evenly mixed; when the mixing time is longer than 10 minutes, it will cause over-milling of the rubber, resulting in a significant decline in the mechanical properties of the rubber compound.

[0016] Step S2: Place the cooled first-stage mixed rubber in a torque rheometer. The rotor speed is 30 - 70 rpm, and the mixing is carried out for 2 - 6 minutes. The discharge temperature is 130 - 150 °C to obtain the second-stage mixed rubber, which is parked and cooled at room temperature for standby. Among them: If the second-stage mixing time is less than 2 minutes, the silanization reaction of silica will be insufficient, affecting the interfacial interaction between silica and rubber, and the performance of the tread rubber composition will deteriorate; when the mixing time exceeds 6 minutes, the rubber compound will undergo cross-linking, oxidative fracture, etc., directly affecting the processability and service performance of the tread rubber composition.

[0017] Step S3: Add the cooled second-stage mixed rubber to a curing package on a two-roll mill for open milling, and then carry out hot press curing to obtain the tread rubber composition.

[0018] Preferably, microcrystalline wax, anti-aging agent, and scorch retardant are also added during the first-stage mixing in Step S1.

[0019] The method for mixing the tread rubber composition of the present invention has a high matching degree with the traditional rubber mixing process. Only by in-situ adding the nitrogen-containing polysulfide of the above formula can the modification of the rubber be achieved, without additional steps or special equipment.

[0020] The technical principle adopted by the mixing method of the present invention is as follows: During the mixing process, the polysulfide bonds in the nitrogen-containing polysulfide of the above formula chemically graft with the rubber, introducing nitrogen atoms into the rubber molecular chain to achieve in-situ functionalization of the rubber. Further, the introduced nitrogen atoms can form hydrogen bond interactions with the silanol groups on the surface of silica, and at the same time, can also promote the silanization reaction between the silane coupling agent and silica, thereby improving the dispersion of silica in the rubber matrix, enhancing the interfacial interaction between silica and rubber, and the obtained tread rubber composition has significantly lower hysteresis loss and higher fatigue resistance.

[0021] According to another aspect of the present invention, the present invention also provides a tire, and the tread of the tire is prepared from the above-mentioned low-hysteresis and high-fatigue-resistant tread rubber composition.

[0022] Compared with the prior art, the present invention has the following beneficial technical effects:

[0023] 1) By adding nitrogen-containing polysulfide during rubber mixing, the present invention facilitates the introduction of nitrogen atoms into the rubber molecular chain, achieving in-situ functionalization of the rubber without redundant steps, which is conducive to popularization and application in the industry.

[0024] 2) By adding nitrogen-containing polysulfide during rubber mixing, the introduced nitrogen atoms can form hydrogen bonds with silica, improving its dispersion in the rubber matrix. At the same time, the nitrogen atoms can promote the silanization reaction and enhance the interfacial interaction.

[0025] 3) The tread rubber composition (also known as nitrogen-containing polysulfide-modified silica / rubber composite) prepared by mixing in the present invention has significantly lower hysteresis loss and higher fatigue resistance, meeting the requirements for application in tire treads. Detailed Embodiments

[0026] The following provides a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not intended to limit the present invention.

[0027] Unless otherwise defined, the technical terms used in the following examples have the same meanings as commonly understood by those skilled in the art to which the present invention pertains. The test reagents used in the following examples are all conventional biochemical reagents, unless otherwise specified; the experimental methods are all conventional methods, unless otherwise specified.

[0028] I. Preparation of three nitrogen-containing polysulfides (named A1, A2, and A3 respectively):

[0029] Preparation of nitrogen-containing polysulfide A1: Add 5 kg of sulfur to the reaction kettle and melt it at 150 °C. Then slowly add 5 kg of m-phenylenediamine and stir and react at this temperature for 8 h. The product is dissolved in tetrahydrofuran, and the unreacted sulfur is filtered off. Finally, pour the solution into deionized water, wash the precipitate repeatedly with ethanol, and dry it under vacuum to obtain nitrogen-containing polysulfide A1 with an average x value of 3.2. Its structural formula is as follows:

[0030]

[0031] Preparation of nitrogen-containing polysulfide A2: Add 5 kg of sulfur to the reaction kettle and melt it at 150 °C. Then slowly add 5 kg of N,N'-dimethyl-4-vinyl aniline and stir and react at this temperature for 8 h. The product is dissolved in tetrahydrofuran, and the unreacted sulfur is filtered off. Finally, pour the solution into deionized water, wash the precipitate repeatedly with ethanol, and dry it under vacuum to obtain nitrogen-containing polysulfide A2 with an average x value of 3.1. Its structural formula is as follows:

[0032]

[0033] Preparation of nitrogen-containing polysulfide A3: Add 5 kg of sulfur into a reaction kettle, melt it at 130 °C, slowly add 3 kg of styrene, stir and react at this temperature for 5 h, then raise the temperature to 150 °C, slowly add 2 kg of N,N'-dimethyl-4-vinyl aniline, and continue to react for 6 h. The product is dissolved in tetrahydrofuran, and the unreacted sulfur is removed by filtration. Finally, pour the solution into deionized water, wash the precipitate repeatedly with ethanol, and dry it under vacuum to obtain nitrogen-containing polysulfide A3 with an average x value of 2.7. Its structural formula is as follows:

[0034]

[0035] II. Further preparation of a series of rubber composites based on the above-prepared nitrogen-containing polysulfides A1, A2, and A3:

[0036] According to the formula in Table 1, add raw rubber, white carbon black, silane coupling agent, nitrogen-containing polysulfide, activator, microcrystalline wax, and antioxidant into a torque rheometer in sequence for the first-stage mixing for 5 min, control the rotation speed to discharge the rubber at 60 °C to obtain a mixed rubber; then let the mixed rubber stand and cool at room temperature, place the cooled rubber material in the torque rheometer for the second-stage mixing for 5 min, control the rotation speed to discharge the rubber at 130 °C; after cooling, add a vulcanization package on a two-roll mill, make a triangular package and then take off the sheet, and then let it stand overnight, and press and vulcanize at 150 °C according to the optimum vulcanization time to obtain a rubber composite sample. According to the corresponding formula, the obtained samples are named: Sample 1, Sample 2, Sample 3, Sample 4, and Sample 5 respectively.

[0037] According to the formula in Table 1, add raw rubber, white carbon black, silane coupling agent, nitrogen-containing polysulfide, activator, microcrystalline wax, processing oil, and antioxidant into a torque rheometer in sequence for the first-stage mixing for 7 min, control the rotation speed to discharge the rubber at 70 °C to obtain a mixed rubber; then let the mixed rubber stand and cool at room temperature, place the cooled rubber material in the torque rheometer for the second-stage mixing for 6 min, control the rotation speed to discharge the rubber at 150 °C; after cooling, add a vulcanization package on a two-roll mill, make a triangular package and then take off the sheet, and then let it stand overnight, and press and vulcanize at 150 °C according to the optimum vulcanization time to obtain a rubber composite sample. According to the corresponding formula, the obtained samples are named: Sample 6 and Sample 7 respectively.

[0038] According to the formula in Table 1, add raw rubber, white carbon black, silane coupling agent, activator, microcrystalline wax, and antioxidant into a torque rheometer in sequence for the first-stage mixing for 5 min, control the rotation speed to discharge the rubber at 60 °C to obtain a mixed rubber; then let the mixed rubber stand and cool at room temperature, place the cooled rubber material in the torque rheometer for the second-stage mixing for 5 min, control the rotation speed to discharge the rubber at 130 °C, after cooling, add a vulcanization package on a two-roll mill, make a triangular package and then take off the sheet, and then let it stand overnight, and press and vulcanize at 150 °C according to the optimum vulcanization time to obtain a rubber composite sample. According to the corresponding formula, the obtained sample is named: Comparative Sample 1.

[0039] According to the formula in Table 1, raw rubber, silica, silane coupling agent, activator, microcrystalline wax, processing oil, and antioxidant were sequentially added to a torque rheometer for the first-stage mixing for 7 min. The rotation speed was controlled to discharge the rubber at 70 °C to obtain a mixed rubber; then the mixed rubber was parked and cooled at room temperature. The cooled rubber compound was placed in a torque rheometer for the second-stage mixing for 6 min. The rotation speed was controlled to discharge the rubber at 150 °C. After cooling, a vulcanization package was added on an open mill, the triangular package was made, and then the sheet was taken off. After parking overnight, it was molded and vulcanized at 150 °C according to the optimum vulcanization time to obtain a rubber composite sample. According to the corresponding formula, the obtained sample was named: Comparative Sample 2.

[0040] Table 1 Tread Compound Formula

[0041]

[0042] Note: The dosage unit of each component in Table 1 is "parts by weight"; VSL 4526-2 SSBR is solution styrene-butadiene rubber with an oil content of 37.5 phr; SSBR2466 is functionalized solution styrene-butadiene rubber with a model number of 2466 and no oil filling. During the mixing process of the tread compound, additional processing oil is usually required as a plasticizer.

[0043] The situation of the rubber additive systems used in the preparation of the above series of rubber composites is as follows:

[0044] Rubber additive system ① (used for Samples 1-4 and Comparative Sample 1) includes: activator: zinc oxide 2.5 parts, stearic acid 1.5 parts; antioxidant 6PPD 2.7 parts; microcrystalline wax 2.7 parts; scorch retarder CTP 0.15 parts; vulcanization package: accelerator CZ 2.8 parts, accelerator DPG 1.6 parts, sulfur 1.5 parts.

[0045] Rubber additive system ② (used for Samples 5-7 and Comparative Sample 2) includes: activator: zinc oxide 4.0 parts, stearic acid 2.0 parts; antioxidant 6PPD 3 parts; microcrystalline wax 3 parts; scorch retarder CTP 0.2 parts; vulcanization package: accelerator CZ 2.5 parts, accelerator DPG 1.2 parts, sulfur 1.5 parts.

[0046] III. Performance testing of the series of rubber composite samples prepared above:

[0047] Testing standards for tensile strength, elongation at break, and 300% modulus: ISO 37 - 2005, test temperature is room temperature, and tensile rate is 500 mm / min; testing standard for heat build-up during fatigue: ISO 4666 - 3:2016; loss factor tanδ (at 7% strain and 10 Hz frequency, 60 °C) is measured using RPA; fatigue threshold refers to the minimum energy required for crack propagation in rubber composites under cyclic loading, the testing instrument is a three-station tear fatigue testing machine, and the test temperature is room temperature; the test method for crack growth rate is as follows: at 800 J / m 2 energy release rate, at 5 Hz frequency, observe the crack depth increase of the pre-notched sample after 20,000 cycles, and then divide the crack depth increase by the number of cycles. The test characterization results of the obtained samples are shown in Table 2.

[0048] Table 2 Quasi-static mechanical properties and dynamic properties

[0049]

[0050] Combining Comparative Sample 1 and Samples 1 - 3, it can be seen that in the system with oil-extended styrene-butadiene rubber and cis-butadiene rubber as raw rubbers, compared with before modification, when adding 0.1 - 0.5 wt% of nitrogen-containing polysulfide A1, the tensile strength and 300% modulus of the rubber composites are significantly improved, the loss factor and fatigue temperature rise are significantly reduced, the fatigue threshold is increased, and the crack growth rate is decreased. With the increase of the addition amount of A1, the improvement amplitude of the above properties increases. It shows that introducing nitrogen-containing polysulfide into rubber composites can effectively improve the quasi-static mechanical properties, dynamic heat generation, and fatigue resistance of rubber composites. However, combining Samples 1 - 4, it can be seen that when the addition amount of nitrogen-containing polysulfide exceeds 0.5 wt% of the raw rubber weight, the elongation at break and fatigue resistance of the tread rubber material significantly decrease, because too much nitrogen-containing polysulfide participates in rubber crosslinking, increasing the crosslinking density and restricting the network movement. Combining Comparative Sample 1 and Samples 2, 5, it can be seen that after adding an equal amount of nitrogen-containing polysulfide A2, there is a similar improvement effect on rubber composites, indicating that the modification effect of nitrogen-containing polysulfides with different structures on rubber is universal.

[0051] Combining Comparative Sample 2 and Samples 6 - 7, it can be seen that in the system with functionalized solution styrene-butadiene rubber and natural rubber as raw rubbers, the tensile strength and 300% modulus of the rubber composites added with nitrogen-containing polysulfide are significantly improved, the loss factor and fatigue temperature rise are significantly reduced, the fatigue threshold is increased, and the crack growth rate is decreased. At the same time, the comprehensive performance of the rubber composites prepared with nitrogen-containing polysulfide A2 is better than that of A3, because the amino content in polysulfide A2 is higher, making the in-situ functionalization degree of rubber higher, which can more effectively promote the silanization reaction and interact with silica, thus improving the sample performance.

[0052] Although the specific embodiments of the present invention have been described above, those skilled in the art should understand that these are only illustrative examples, and various changes or modifications can be made to these embodiments without departing from the principles and essence of the present invention. The protection scope of the present invention is only defined by the appended claims.

Claims

1. A low hysteresis and high fatigue-resistant tread rubber composition, characterized in that, It includes raw rubber, silica, nitrogen-containing polysulfide, silane coupling agent and vulcanization package; The weight of silica is 40-100 wt% of the raw rubber, the weight of the silane coupling agent is 4-10 wt% of the silica, and the weight of the nitrogen-containing polysulfide is 0.1-0.5 wt% of the raw rubber; The chemical general formula of the nitrogen-containing polysulfide is: Wherein x is an integer from 2 to 6; R1 is an aromatic ring structure molecule; R2 is a fatty chain molecule or an aromatic ring molecule containing a nitrogen atom, and the fatty chain molecule is selected from a linear fatty chain molecule or a branched fatty chain molecule.

2. The low hysteresis and high fatigue resistant tread rubber composition according to claim 1, characterized in that, The raw rubber is mainly one or more of diene rubber, styrene-butadiene rubber, natural rubber and cis-1,4-polybutadiene rubber.

3. The low hysteresis, high fatigue resistant tread rubber composition according to claim 1, characterized in that, It also includes at least one of microcrystalline wax, anti-aging agent and scorch retarder.

4. The kneading method of the low hysteresis and high fatigue-resistant tread rubber composition according to any one of claims 1-3, characterized in that, It includes the following steps: S1. Add the raw rubber, silica, silane coupling agent and nitrogen-containing polysulfide into a torque rheometer for mixing, with the rotor speed of 20-40 rpm, mixing for 3-10 minutes, discharging the rubber at 50-70 °C to obtain the first-stage mixed rubber; S2. Place the cooled first-stage mixed rubber in a torque rheometer, with the rotor speed of 30-70 rpm, mixing for 2-6 minutes, and the discharging temperature of 130-150 °C to obtain the second-stage mixed rubber; S3. Add the vulcanization package to the cooled second-stage mixed rubber on an open mill for open milling and hot press vulcanization to obtain the tread rubber composition.

5. The kneading method of the low hysteresis and high fatigue resistant tread rubber composition according to claim 4, characterized in that, The mixed products of the first-stage mixed rubber and the second-stage mixed rubber are parked and cooled to room temperature at room temperature.

6. The kneading method of the low hysteresis and high fatigue-resistant tread rubber composition according to claim 4, characterized in that, When performing the first-stage mixing in step S1, at least one of microcrystalline wax, anti-aging agent and scorch retarder is also added.

7. A tire, characterized in that, The tread of the tire is prepared from the low hysteresis and high fatigue-resistant tread rubber composition according to any one of claims 1-3.

Images