TBR tire tread composition with A-grade rolling resistance and slagging resistance and preparation method of TBR tire tread composition

Abstract

The invention discloses a grade-A rolling resistance slagging-off TBR tire tread composition and a preparation method thereof, and relates to the technical field of tire preparation, the grade-A rolling resistance slagging-off TBR tire tread composition is prepared from the following raw materials by weight: 80 parts of natural rubber, 20 parts of solution polymerized styrene-butadiene rubber, 15 parts of N220 carbon black, 30 parts of high-dispersion high-performance white carbon black, 3 parts of talcum powder, 4 parts of an anti-aging agent, 7.8 parts of a modified silane coupling agent, 3.5 parts of zinc oxide, and 2 parts of modified stearic acid. 2 parts of a processing aid, 2.5 parts of an accelerant, 1.8 parts of sulfur and 1.2 parts of modified nano cellulose. The blending matrix formed by the natural rubber and the solution polymerized styrene-butadiene rubber is matched with the modified silane coupling agent and the high-dispersion and high-performance white carbon black to achieve the synergistic effect, the blending matrix can achieve elastic complementation, the modified silane coupling agent can improve the compatibility of the white carbon black and the rubber, and the modified silane coupling agent can improve the compatibility of the white carbon black and the rubber. The white carbon black is uniformly dispersed in a rubber matrix through a primary mixing process of an engaged internal mixer, so that the advantage of low hysteresis of the white carbon black is fully exerted.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tire preparation, in particular to a TBR tire tread composition with A-level rolling resistance and anti-dropping and a preparation method thereof. BACKGROUND

[0002] With the promotion of global energy-saving and emission-reduction policies and the increasing demand of commercial vehicle industry for operating cost control, the market puts forward more stringent requirements for the rolling resistance coefficient of TBR tires, and the A-level rolling resistance coefficient has become a core technical index and market competition key of low-rolling-resistance TBR tires. As the core component affecting the overall rolling resistance, the formula design of the tire tread directly determines the rolling resistance performance of the tire.

[0003] The traditional formula adopts a single natural rubber as the matrix, which can guarantee the basic wear, heat generation and tear resistance of the tread. However, due to the existence of the devil's triangle, in order to reduce the rolling resistance and optimize the heat generation hysteresis performance of the rubber compound, the traditional formula usually uses the method of reducing the amount of reinforcing agent, and uses ordinary silane coupling agent to improve the interface bonding between white carbon black and rubber. However, the reaction efficiency of the active group of the ordinary silane coupling agent with the rubber molecule is low, which easily leads to the agglomeration of the white carbon black in the rubber matrix, and the low hysteresis advantage of the white carbon black cannot be fully played, thereby affecting the rolling resistance performance of the tire, and also affecting the wear performance of the tire. In addition, there is a common problem of poor cutting resistance, which may cause dropping and blockage in actual use. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a TBR tire tread composition with A-level rolling resistance and anti-dropping and a preparation method thereof, which solves the problems mentioned in the background.

[0005] To achieve the above purpose, the present application realizes the technical scheme as follows: In a first aspect, the present application provides a TBR tire tread composition with A-level rolling resistance and anti-dropping, which is made of the following raw materials by weight: 80 parts of natural rubber, 20 parts of solution-polymerized styrene-butadiene rubber, 15 parts of N220 carbon black, 30 parts of high-dispersion high-performance white carbon black, 3 parts of talcum powder, 4 parts of anti-aging agent, 7.8 parts of modified silane coupling agent, 3.5 parts of zinc oxide, 2 parts of modified stearic acid, 2 parts of processing aid, 2.5 parts of accelerator, 1.8 parts of sulfur and 1.2 parts of modified nanocellulose.

[0006] Preferably, the anti-aging agent includes RD, 6PPD and microcrystalline wax, and the mass ratio of RD, 6PPD and microcrystalline wax is 2:2:1.

[0007] Preferably, the preparation raw material of the modified silane coupling agent is a mixed silane containing a carbon black carrier, the mass ratio of the carbon black carrier in the mixed silane is 50%, and Si75 and Si69 in the mixed silane are matched in a mass ratio of 1:1, and the specific modification process is as follows: The mixed silane containing the carbon black carrier is dissolved in toluene, maleic anhydride is added, and stirring is carried out at 80-90℃ under nitrogen protection for 3-4h. After the reaction is completed, toluene is removed by distillation under reduced pressure to obtain the modified silane coupling agent; The addition amount of maleic anhydride is 8%-12% of the total mass of Si75 and Si69. The grafting rate of maleic anhydride of the modified silane coupling agent is 5%-8%.

[0008] Preferably, the modified stearic acid is obtained by esterification of stearic acid with glycerol. The specific modification process is as follows: Stearic acid and glycerol are mixed at a molar ratio of 2:1, and 0.5%-1% of p-toluenesulfonic acid is added as a catalyst. The mixture is stirred at 120-130℃ for 2-3h to allow esterification between the carboxyl group of stearic acid and the hydroxyl group of glycerol, thereby generating a modified product mainly composed of monostearate glycerol. After the reaction is completed, unreacted glycerol and catalyst are removed by distillation under reduced pressure to obtain the modified stearic acid. The esterification degree of the modified stearic acid is 85%-90%, and the acid value is ≤5mgKOH / g. The modified stearic acid contains 3%-8% of unreacted stearic acid, and the unreacted stearic acid and the modified stearic acid synergistically activate the vulcanization system in the tread composition and improve the processing fluidity of the rubber compound.

[0009] Preferably, the accelerator is a sulfenamide accelerator, specifically CBS or NS.

[0010] Preferably, the modified nanocellulose is obtained by esterification of microcrystalline cellulose with citric acid. The specific modification process is as follows: The microcrystalline cellulose is dispersed in a 40%-50% water-ethanol mixture, and stirred at a speed of 1500-2000rpm for 10-15min to preliminarily depolymerize the microcrystalline cellulose. Citric acid is added at a mass fraction of 10%-15% of the microcrystalline cellulose, and anhydrous sodium carbonate is added at a mass fraction of 3%-5% of the citric acid. The mixture is heated to 80-90℃ and stirred for 2.5-3.5h to allow esterification between the carboxyl group of citric acid and the hydroxyl group on the surface of the microcrystalline cellulose, thereby forming a carboxyl modified layer on the surface of the nanocellulose. After the reaction is completed, the mixture is separated by suction filtration, and the obtained solid is washed with deionized water until neutral, and then vacuum dried at 70-80℃ for 4-5h to obtain the modified nanocellulose. The particle size of the modified nanocellulose is 10-50nm, and the esterification degree is 12%-18%.

[0011] In a second aspect, the embodiments of the present application provide a preparation method of a TBR tire tread composition with A-level rolling resistance and anti-dropping, for preparing a TBR tire tread composition with A-level rolling resistance and anti-dropping, comprising the following steps: S1, add 80 parts of natural rubber and 20 parts of solution polymerized styrene-butadiene rubber into an intermeshing mixer, set the mixer speed at 55 rpm, first mix for 25 s to soften the natural rubber, then add 15 parts of N220 carbon black, 30 parts of high-dispersion high-performance white carbon black, 4 parts of antioxidant, 2 parts of modified stearic acid, 3 parts of talc, 7.8 parts of modified silane coupling agent, 2 parts of processing aid, and 1.2 parts of modified nanocellulose, continue mixing for 15 s, stop the mixer 2-3 times to exhaust and cool down, each time the stop time is 3-5 s, when the temperature of the material in the intermeshing mixer reaches 150 DEG C, discharge the material, and obtain a first-stage masterbatch; S2, add the first-stage masterbatch obtained in step S1 and 3.5 parts of zinc oxide into a one-step mixer, set the mixer speed at 45 rpm, mix for 60 s, then stop the mixer for 10 s, then continue mixing until the temperature of the material reaches 150 DEG C, discharge the material, and then transfer the discharged material to an open mill, mix and cool to 90-100 DEG C, then add 2.5 parts of accelerator and 1.8 parts of sulfur, mix for 300 s, and finally discharge and cool to room temperature to obtain a finished rubber, which is a TBR tire tread composition with A-grade rolling resistance and anti-dropping.

[0012] Preferably, in step S1, the DBP absorption value of the high-dispersion high-performance white carbon black is 185-230.0 mL / 100 g, the iodine absorption value of the N220 carbon black is 119-133 g / kg, and the DBP absorption value is 108-120 x 10 -5 m 3 / kg.

[0013] Preferably, in step S2, after the discharged material is transferred to the open mill, the material is mixed and cooled in a ring on the cooling belt during the mixing and cooling process.

[0014] Preferably, in step S2, the temperature of the mixing chamber of the one-step mixer is initially controlled at 60-70 DEG C, and the roll gap of the open mill is controlled at 3-5 mm.

[0015] Preferably, in step S2, the roll temperature of the open mill is controlled at no more than 100 DEG C during the mixing and cooling process, and the mixing and cooling frequency is 5-8 times.

[0016] The present application provides a TBR tire tread composition with A-grade rolling resistance and anti-dropping and a preparation method thereof, which has the following beneficial effects: (1) The natural rubber and the solution polymerized styrene-butadiene rubber form a blended matrix, which is matched with modified silane coupling agent and high-dispersed high-performance white carbon black to realize the synergistic effect, the blended matrix can realize the complementary elasticity, the modified silane coupling agent can improve the compatibility of the white carbon black and the rubber, and the white carbon black is uniformly dispersed in the rubber matrix through the initial mixing process of the meshing mixer to fully exert the low hysteresis advantage; when the tread composition is applied to the TBR tire, the energy loss in the rolling process of the tire can be effectively reduced to reach the A-grade rolling resistance coefficient level, the demand of the market for the low rolling resistance tire is met, and strong support is provided for the energy saving and emission reduction of the vehicle; (2) A synergistic reinforcing system is constructed by the high-dispersed high-performance white carbon black and the N220 carbon black, the three-dimensional network structure strength of the rubber is improved by the basic reinforcing capacity of the N220 carbon black and the high specific surface area characteristics of the white carbon black, the interface bonding force between the modified nanocellulose reinforcing filler and the rubber is matched, and the uniform vulcanization effect brought by the sulfenamide type accelerator is matched, so that the tread rubber forms a stable and tough structure; this system solves the problem of insufficient reinforcement of the traditional low rolling resistance formula, enhances the strength and tear strength of the tread rubber, improves the wear resistance, so that the tire can resist road impact, cutting and other damages during driving, and guarantees the structural stability and reliability during use; (3) By setting the speed of the meshing mixer and the primary mixer, matching the process details such as the intermediate bolt exhaust and the folding cooling of the open mill, the problem of easy agglomeration and uneven dispersion of the high specific surface area white carbon black in the processing is solved; at the same time, the compatibility of the raw material system and the matching of the process parameters make the flow uniformity of the tread rubber in the extrusion process, finally realize the effect of smooth extrusion of the tread without edge, and the inflation range of the die is reduced, this advantage not only improves the appearance quality of the tire tread, but also guarantees the dimensional consistency in batch production process, reduces the waste rate in the processing process, provides stable and reliable technical support for large-scale industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The preparation flow chart provided by the present application; Figure 2 The product diagram corresponding to example 3 provided by the present application; Figure 3 The product diagram corresponding to example 5 provided by the present application. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application, obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0019] The current TBR tire tread formula technology of A-level rolling resistance coefficient, adopts silica combined with silane coupling agent to replace traditional carbon black, or reduces the overall reinforcing system to reduce the hysteresis of vulcanized rubber, but these two ways have the following defects: on the one hand, the reinforcing system is usually 40-50 parts, the filler is not enough to reinforce the rubber, and the tire is easy to appear dropping phenomenon on the poor road, not only shortens the service life, but also may cause the risk of tire burst caused by steel wire corrosion; on the other hand, it will make the tire wear performance decline, which cannot meet the basic requirements of customers on tire wear, which restricts the large-scale market application of A-level rolling resistance coefficient TBR tire.

[0020] It should be noted that the "A-level" rolling resistance coefficient is defined according to the domestic and international tire performance label standards, and for TBR tire, it usually refers to the rolling resistance coefficient (RRC) ≤ 4.0 N / kN, which is the highest performance level set by the current market for low rolling resistance tires.

[0021] In view of the above problems existing in the prior art, the embodiment of the present application provides a TBR tire tread composition with A-level rolling resistance and anti-dropping and a preparation method thereof. By screening modified raw materials and optimizing the preparation process, specific components such as modified silane coupling agent, modified stearic acid and modified nanocellulose are introduced, the key performances of tire rolling resistance, wear, cutting resistance and dropping are synergistically improved, and the use pain points of the existing low rolling resistance TBR tire tread are effectively solved.

[0022] The A-level rolling resistance and anti-dropping TBR tire tread composition of the embodiment of the present application is prepared by blending 80 parts of natural rubber and 20 parts of solution polymerized styrene-butadiene rubber, high dispersion and high performance silica, N220 carbon black, modified silane coupling agent, modified stearic acid and modified nanocellulose, and using a combined one-step mixing method of meshing internal mixer. The composition not only retains the low rolling resistance characteristics, but also makes up for the problems of dropping and poor wear caused by insufficient reinforcement. Compared with the traditional formula, the composition further improves the strength and elongation, tear strength and wear resistance without reducing the rolling resistance coefficient, optimizes the processing technology, and realizes industrialized production.

[0023] In the present application, the selection of raw materials for the tread composition is based on the principle of performance complementation, and each component synergistically acts to break through the problems of rolling resistance, wear, and anti-dropping. Among them, the DBP absorption value of high dispersion and high performance silica directly affects its reinforcing effect, the styrene content and glass transition temperature (Tg) of solution polymerized styrene-butadiene rubber determine the elasticity and tear resistance of the rubber, the modified silane coupling agent balances the low hysteresis and tear resistance of silica, the modified stearic acid synergistically activates the vulcanization system and improves the processability, and the modified nanocellulose enhances the interfacial bonding force between the filler and the rubber.

[0024] In some embodiments of the present application, the tread composition comprises a blend of 80 parts of natural rubber and 20 parts of solution styrene-butadiene rubber, wherein the solution styrene-butadiene rubber has a styrene mass fraction of 15% to 18% and a Tg≤-50°C. The solution styrene-butadiene rubber with such specific properties synergizes with the natural rubber to improve the rubber's tear resistance, chunking resistance, and maintain low hysteresis properties, thereby ensuring an A-level rolling resistance of the tire.

[0025] In some embodiments of the present application, the solution styrene-butadiene rubber is selected from solution styrene-butadiene rubber 1 and solution styrene-butadiene rubber 2, both of which meet the technical requirements of a styrene mass fraction of 15% to 18% and a Tg≤-50°C, and only differ in the manufacturer. In specific formulations, they can be used alone or in combination according to actual performance requirements. When used in combination with natural rubber, the comprehensive mechanical properties of the rubber can be further optimized.

[0026] In some embodiments of the present application, the reinforcing system uses N220 carbon black in combination with high-dispersion high-performance white carbon black. The N220 carbon black has an iodine adsorption value of 119 to 133 g / kg and a DBP absorption value of 108 to 120 x 10 -5 m 3 / kg, which can provide basic reinforcement; the high-dispersion high-performance white carbon black has a DBP absorption value of 185 to 230.0 mL / 100 g, and its high specific surface area property provides excellent reinforcing effect. The combination of the two can balance low hysteresis and high reinforcing performance. The high-dispersion high-performance white carbon black is selected from high-dispersion high-performance white carbon black 1 and high-dispersion high-performance white carbon black 2, both of which meet the standard of a DBP absorption value of 185 to 230.0 mL / 100 g, and only differ in the manufacturer. The core function of both is to improve the tread rubber's tear resistance, chunking resistance, and wear resistance, while ensuring low rolling resistance.

[0027] In some embodiments of the present application, the modified silane coupling agent is produced by grafting modification of a mixture of Si75 and Si69 with a carbon black carrier content of 50% with maleic anhydride. The specific modification process is as follows: the mixture of Si75 and Si69 is dissolved in toluene at a mass ratio of 1:1, 8% to 12% of maleic anhydride is added based on the mass fraction of the mixture, and the mixture is stirred at 80 to 90°C under nitrogen protection for 3 to 4 hours to allow the unsaturated bonds of maleic anhydride to react with the active groups in the silane coupling agent. After the reaction is completed, toluene is removed by reduced pressure distillation to obtain the modified silane coupling agent. The grafting rate of maleic anhydride is 5% to 8%. Compared with unmodified silane coupling agents, the modified silane coupling agent can more efficiently improve the compatibility of white carbon black and rubber molecules, promote the uniform dispersion of white carbon black, and further balance the low hysteresis performance and the rubber tear strength.

[0028] In some embodiments of the present application, the modified stearic acid is produced by esterification of stearic acid with glycerol, and the specific modification process is as follows: stearic acid and glycerol are mixed at a molar ratio of 2:1, 0.5% to 1% of p-toluenesulfonic acid is added as a catalyst, and the mixture is stirred at 120 to 130°C for 2 to 3 hours to allow the carboxyl group of stearic acid to react with the hydroxyl group of glycerol to form a modified product mainly composed of monostearate glycerol. After the reaction is completed, unreacted glycerol and catalyst are removed under reduced pressure to obtain modified stearic acid. The esterification degree of the modified stearic acid is 85% to 90%, the acid value is ≤5 mgKOH / g, and it contains 3% to 8% of unreacted stearic acid based on the total amount. The unreacted stearic acid can synergistically act with the modified stearic acid to assist in activating the vulcanization system in the tread composition, generating zinc stearate with zinc oxide, improving the processing flowability of the rubber compound, and avoiding the softening problem of the rubber compound caused by excessive use of traditional stearic acid.

[0029] In some embodiments of the present application, the modified nanocellulose is produced by esterification of microcrystalline cellulose with citric acid, and the specific modification process is as follows: the microcrystalline cellulose is dispersed in a 40% to 50% water-ethanol mixture, and stirred at a speed of 1500 to 2000 rpm for 10 to 15 minutes to preliminarily depolymerize the microcrystalline cellulose; 10% to 15% of citric acid based on the mass fraction of the microcrystalline cellulose is added, and 3% to 5% of anhydrous sodium carbonate based on the mass fraction of the citric acid is added, and the temperature is raised to 80 to 90°C, and the mixture is stirred at constant temperature for 2.5 to 3.5 hours to allow the carboxyl group of the citric acid to react with the hydroxyl group on the surface of the microcrystalline cellulose to form a carboxyl modified layer on the surface of the nanocellulose; after the reaction is completed, the mixture is separated by suction filtration, the obtained solid is washed with deionized water until it is neutral, and then vacuum dried at 70 to 80°C for 4 to 5 hours to obtain the modified nanocellulose; the particle size of the modified nanocellulose is 10 to 50 nm, and the esterification degree is 12% to 18%. The modified nanocellulose can fill the voids of the rubber matrix through nanoscale dispersion characteristics, enhance the interfacial bonding force between the filler and the rubber, and further improve the tear resistance and anti-dust performance of the tread rubber, while not affecting the low rolling resistance characteristics.

[0030] In some embodiments of the present application, 3 parts of talc are added to the tread composition, the SiO2 content of the talc is 60±2%, the MgO content is 30±2%, the acid-insoluble substance content is ≥90%, and the fineness is ≥2000 mesh. The addition of talc in combination with the one-step mixing method of the intermeshing mixer can effectively solve the dispersion problem caused by high content and high specific surface area of the white carbon black and the modified nanocellulose, and the processing difficulty problem caused by the silanization reaction, and improve the processing flowability of the rubber compound.

[0031] In some embodiments of the present application, the anti-aging agent is a combination of RD, 6PPD and microcrystalline wax, with a mass ratio of 2:2:1. The combined anti-aging agent system can synergistically play the roles of anti-oxidation and anti-ozone aging, delay the aging speed of the tire tread during use, and prolong the service life of the tire. The accelerator is selected from the group consisting of sulfenamides, specifically CBS or NS, which can regulate the vulcanization reaction rate, make the rubber vulcanization more uniform and sufficient, and ensure the performance stability of the vulcanized rubber.

[0032] In some embodiments of the present application, the mixing process for preparing the tread composition adopts a combination of an intermeshing internal mixer and a single method internal mixer, with the rotational speed of the intermeshing internal mixer set to 55 rpm and the rotational speed of the single method internal mixer set to 45 rpm. This rotational speed parameter can ensure sufficient mixing of the raw materials, while avoiding the rapid increase in the temperature of the rubber compound caused by excessively high rotational speed, thereby preventing the rubber from being scorched or deteriorated due to excessive silanization reaction in the early stage.

[0033] In some embodiments of the present application, the discharge temperature of the intermeshing internal mixer in step S1 is controlled at 150°C, and the discharge temperature of the single method internal mixer in step S2 is also controlled at 150°C. The discharge temperature of 150°C is determined by considering the efficiency of silanization reaction and the stability of rubber performance. At this temperature, the silanization reaction can proceed sufficiently, and the molecular structure of the rubber will not be damaged.

[0034] Illustratively, when talc is added to the tread composition and a solution polymerized styrene-butadiene rubber is used, the mechanism of the mixing process in the embodiments of the present application is as follows: in the intermeshing internal mixer, the natural rubber and the solution polymerized styrene-butadiene rubber are first mixed for 25 s to achieve preliminary fusion, and then the talc added can reduce the agglomeration force between the silica particles. In combination with 2-3 times of unstacking and exhaust during the process, the temperature is lowered to further promote the uniform dispersion of the silica in the rubber matrix. In the single method internal mixer, after the first-stage masterbatch and zinc oxide are sufficiently mixed, the sulfur and the accelerator are added when the temperature is cooled to 90-100°C by the open mill. This temperature range can avoid premature crosslinking of the sulfur, ensuring the orderly progress of the vulcanization reaction.

[0035] In some embodiments of the present application, the unstacking and exhaust time in step S1 is 3-5 s each time. Reasonable unstacking and exhaust time can effectively exhaust the gas generated during the mixing process, reduce the internal bubbles of the rubber compound, and avoid insufficient mixing shear caused by excessive unstacking and exhaust time, which affects the mixing efficiency and mixing effect.

[0036] In some embodiments of the present application, after the material is discharged in step S2, the material is transferred to the open mill, and during the rolling and cooling process, the rubber compound needs to be passed through the open mill and form a loop on the cooling belt to ensure uniform cooling of the material, avoid excessive local temperature affecting the addition effect of the sulfur and the accelerator in the subsequent process, and improve the uniformity of the rubber compound.

[0037] In some embodiments of the present application, the temperature of the mixing chamber of the single method internal mixer in step S2 is initially controlled at 60-70°C, and the roll gap of the open mill is controlled at 3-5 mm. The initial temperature setting can avoid uneven mixing of the masterbatch between batches due to excessively low or high temperature, and precise control of the roll gap can ensure uniform thickness of the rubber compound, laying a foundation for subsequent thin pass mixing and sheeting cooling.

[0038] It can be understood that excessively high roll temperature of the open mill during thin pass mixing can cause premature vulcanization of sulfur, affecting the performance of the rubber compound. Therefore, in some embodiments of the present application, the roll temperature of the open mill during thin pass mixing in step S2 is controlled to be no more than 100°C, and the number of thin pass mixing is 5-8 times. This parameter setting can ensure that sulfur and accelerators are fully integrated with the rubber compound, and can prevent the rubber compound from scorching, ensuring stable performance of the final rubber compound.

[0039] In some specific embodiments, the roll temperature of the open mill can be controlled to be 85°C, 90°C, 95°C, 100°C, etc., and the number of thin pass mixing can be set to 5 times, 6 times, 7 times, 8 times, etc., which can be flexibly adjusted according to the softening degree and mixing state of the rubber compound in actual production.

[0040] The present application also provides a TBR tire tread composition with A-level rolling resistance and anti-dropping slag prepared by the preparation method of any one of the preceding embodiments. The composition can be applied to mainstream specifications of TBR tires such as 12R22.5, and the rolling resistance coefficient can be stably reached at the level of 4.0 through actual testing, meeting the market requirements for low rolling resistance tires.

[0041] The A-level rolling resistance and anti-dropping slag TBR tire tread composition and its preparation method provided by the present application are described in detail below in combination with specific embodiments.

[0042] Embodiments 5 and 6 The A-level rolling resistance and anti-dropping slag TBR tire tread composition provided by embodiments 5 and 6 is made of the following raw materials in parts by weight: 80 parts of natural rubber, 20 parts of solution-polymerized styrene-butadiene rubber, 15 parts of N220 carbon black, 30 parts of high-dispersion high-performance white carbon black 2, 3 parts of talc, 4 parts of antioxidant, 7.8 parts of modified silane coupling agent, 3.5 parts of zinc oxide, 2 parts of modified stearic acid, 2 parts of processing aid, 2.5 parts of accelerator, 1.8 parts of sulfur, and 1.2 parts of modified nanocellulose. In embodiment 5, solution-polymerized styrene-butadiene rubber 1 is selected, and in embodiment 6, solution-polymerized styrene-butadiene rubber 2 is selected.

[0043] Referring to the accompanying drawings, Figure 1 The preparation method of the tread composition includes the following steps S1 to S2.

[0044] In some embodiments of the present application, the mixing process for preparing the tread composition adopts a combination of intermeshing internal mixers and single method internal mixers, and the specific steps are as follows: S1, add 80 parts of natural rubber and 20 parts of solution-polymerized styrene-butadiene rubber into an intermeshing mixer, set the mixer speed to 55 rpm, first mix for 25 s to soften the rubber, then add 15 parts of N220 carbon black, 30 parts of high-dispersion high-performance white carbon black 2, 4 parts of antioxidant, 2 parts of modified stearic acid, 3 parts of talc, 7.8 parts of modified silane coupling agent, 2 parts of processing aid, 1.2 parts of modified nanocellulose, continue to mix for 15 s, stop the mixer 2-3 times in the middle to exhaust and cool down, each time the mixer is stopped for 3-5 s, and the material in the intermeshing mixer is discharged when the temperature reaches 150℃, to obtain a first-stage masterbatch; in this step, the modified stearic acid is added at the same time as the stearic acid, and the modified nanocellulose is added simultaneously with the fillers to ensure uniform dispersion in the rubber matrix; S2, add the first-stage masterbatch obtained in step S1 and 3.5 parts of zinc oxide into a one-step mixer, control the initial temperature of the mixing chamber of the one-step mixer to be 60-70℃, set the speed to 45 rpm, mix for 60 s, then stop the mixer for 10 s, and then continue mixing until the material temperature reaches 150℃ and the material is discharged; the discharged material is transferred to an open mill, the roll gap of the open mill is controlled to be 3-5 mm, and the material is folded every 15-20 s during the folding and cooling process, 2.5 parts of accelerator and 1.8 parts of sulfur are added when the material cools to 90-100℃, the roll temperature of the open mill is controlled to be no more than 100℃, the material is thin-folded and rolled for 300 s, the thin-folded and rolled times are 5-8 times, and finally the material is discharged and cooled to room temperature to obtain a finished rubber, which is a TBR tire tread composition with A-grade rolling resistance and anti-dropping slag.

[0045] In some embodiments of the present application, the vulcanization condition of the tread composition is 151℃×30min, which is matched with the rubber formula, can make the rubber molecules form a stable crosslinked network, fully play the synergistic effect of modified raw materials and basic components, and make the tread rubber achieve the best mechanical properties and use performance.

[0046] The A-grade rolling resistance and anti-dropping slag TBR tire tread composition and the preparation method thereof provided by the present application are described in detail below in combination with specific embodiments, wherein examples 5 and 6 are the optimal scheme, and the tread composition and the preparation method provided by examples 1-4 and comparative example 1 are basically the same as example 1, and the differences are shown in table 1.

[0047] ; 1. Logical explanation of each example formula: Example 1: 100 parts of natural rubber, 30 parts of high-dispersion high-performance white carbon black 1, 6 parts of ordinary silane coupling agent, and 2 parts of ordinary stearic acid, without modified components, to verify the low rolling resistance and reinforcement balance of the basic formula; Example 2: Highly dispersed high-performance silica 1 was replaced with highly dispersed high-performance silica 2, the ordinary silane coupling agent remained unchanged, and ordinary stearic acid was replaced with 2 parts of modified stearic acid to verify the improvement of sulfurization activation and processability by modified stearic acid. Example 3: Based on Example 2, 6 parts of ordinary silane coupling agent were replaced with 7.8 parts of modified silane coupling agent to verify the optimization of filler dispersion and low hysteresis by modified silane; Example 4: Based on Example 3, 3 parts of talc powder and 1.2 parts of modified nanocellulose were added to verify the dispersing aid effect of talc powder and the reinforcing and synergistic effect of modified nanocellulose. Examples 5-6: 80 parts of natural rubber, 20 parts of solution-polymerized styrene-butadiene rubber (1 or 2), and 7.8 parts of modified silane, 2 parts of modified stearic acid, 1.2 parts of modified nanocellulose, and 3 parts of talc powder were used in Example 4 to verify the optimal synergistic performance of the blend matrix and the fully modified components.

[0048] 2. Performance Test Results and Analysis Performance tests were conducted on the vulcanized tread rubbers of all embodiments and comparative examples. The results are shown in Table 2, and additionally attached... Figure 2 The product diagram corresponding to Example 3 is shown, with appendix. Figure 3 The product diagram corresponding to Example 5 is shown. Key performance improvements are as follows: Low rolling resistance performance: Tanδ of Examples 3 to 6 is ≤0.069, resilience is ≥64.6%, and rolling resistance coefficient is stably 4.0 or below (Grade A standard). Among them, due to the optimization of modified silane, Tanδ of Example 3 is as low as 0.063, which is better than the ordinary silane group. Anti-scraping and abrasion resistance: In Examples 4-6, due to the reinforcement of modified nanocellulose, the tear strength is ≥83.5 N / mm, and the DIN abrasion wear is ≤124.5 mm. 3 The cutting depth resistance is ≤18.2mm, a significant improvement compared to Comparative Example 1; the blended matrices of Examples 5 and 6 further optimize abrasion, with Akron abrasion as low as 0.15–0.16cm. 3 / 1.61km, which is the optimal level; Processing performance: Modified stearic acid maintains the Mooney viscosity of the rubber compound at 72-82.1, making it easier to extrude than ordinary stearic acid compounds, and with less die swell.

[0049] Table 2: Test Results of Tread Rubber Properties After Vulcanization ; Note: G' represents storage modulus, G" represents loss modulus, Tan delta represents loss factor; Test method: Cut resistance: using 500g blade, free falling from 80cm height, cutting the test tread rubber below to form a cut, the cut depth value is used as the evaluation index of the cut resistance, the larger the value, the worse the cut resistance; Resilience according to GB / T 1681; Bottom and middle heat build-up according to GB / T 1687.3; Hardness according to GB / T 531.1; Deflection, tensile strength, elongation at break according to GB / T 528; Tear according to GB / T 529; Mooney viscosity value according to GB / T 1232.1; DIN abrasion according to GB / T 9867; Akron abrasion according to GB / T 1689; Tensile strength and elongation product: the product of tensile strength and tensile elongation.

[0050] By comparing examples 1-6 with comparative example 1, it can be seen that in the tread composition and preparation method of examples 1-6 of the application, high-dispersed high-performance white carbon black is used to replace the ordinary high-dispersed white carbon black of comparative example 1, and modified stearic acid, modified silane coupling agent, modified nanocellulose and talc are gradually introduced, which can improve the tear resistance, wear resistance and cut resistance of the tread rubber compared with the traditional formula of comparative example 1, while maintaining the A-level low rolling resistance property. Among them, examples 5 and 6 use a blend system of 80 parts of natural rubber and 20 parts of solution-polymerized styrene-butadiene rubber, and are matched with fully modified ingredients. The DIN abrasion is as low as 114.6mm 3 and 116.6mm 3 , the Akron abrasion is as low as 0.15cm 3 / 1.61km and 0.16cm 3 / 1.61km, the cut resistance depth is only 16.9mm and 16.7mm, and all indicators are better than those of comparative example 1, which reflects the synergistic effect of the blend matrix and modified ingredients.

[0051] As can be seen from examples 3 and 4, when other formula conditions are the same, after adding 3 parts of talc and 1.2 parts of modified nanocellulose in the tread composition, the DIN abrasion of the tread rubber is reduced from 125.1mm 3 to 124.5mm 3 , and the dispersion of the rubber compound is better during the mixing process; although the tear strength is reduced from 83.7N / mm to 83.5N / mm, the overall mechanical properties and processing stability are more suitable for the needs of industrial continuous production, which shows that the dispersion auxiliary effect of talc and the reinforcing effect of modified nanocellulose can effectively balance the performance and processability.

[0052] As can be seen from Example 1, Example 2 and Example 3, when other conditions are the same, the performance of the tread rubber presents a ladder-type optimization after the ordinary stearic acid is replaced by modified stearic acid and the ordinary silane coupling agent is adjusted to a modified silane coupling agent: compared with Example 1, the tear strength of Example 2 is increased from 86.4 N / mm to 89.1 N / mm, the DIN abrasion is reduced from 132.2 mm 3 to 128.7 mm 3 , which reflects the improvement of the modified stearic acid on the vulcanization activation and wear resistance; compared with Example 2, the Tan delta of Example 3 is reduced from 0.072 to 0.063, the resilience is increased from 64.3% to 65.2%, and the G' is increased from 25.78 MPa to 26.63 MPa, which shows that the modified silane coupling agent can optimize the compatibility of white carbon black and rubber, improve the elasticity and low hysteresis of the rubber, and at the same time, enhance the reinforcing efficiency of the filler.

[0053] As can be seen from Example 4, Example 5 and Example 6, the wear resistance of the tread rubber is improved by using a blend system of 80 parts of natural rubber and 20 parts of solution-polymerized styrene-butadiene rubber: compared with the pure natural rubber formula of Example 4, the DIN abrasion is reduced from 124.5 mm 3 to 114.6-116.6 mm 3 , the Akron abrasion is reduced from 0.18 cm 3 / 1.61 km to 0.15-0.16 cm 3 / 1.61 km, and the cutting resistance is reduced from 18.2 mm to 16.7-16.9 mm; among them, the DIN abrasion and Akron abrasion of Example 5 are the best values in all examples, which shows that the blend system of solution-polymerized styrene-butadiene rubber and natural rubber with specific performance has a synergistic effect on improving the wear resistance and cutting resistance of the tire tread.

[0054] Example 5 and Example 6 optimize the raw material formula and preparation process, so that the tread composition has excellent comprehensive performance: the Tan delta, resilience, bottom heat, and middle heat, which represent the heat hysteresis performance, are maintained at a good level, ensuring that the tire reaches the A-level rolling resistance coefficient; the DIN abrasion and Akron abrasion, which represent the wear resistance, are reduced by 10%-15% compared with the traditional formula; the tear strength, strength-elongation product, and cutting resistance, which represent the cutting resistance and residue resistance, are improved, among which the cutting depth can be controlled at 16.7-16.9 mm, effectively solving the use defects of traditional low-rolling-resistance tires.

[0055] In summary, through the formula design in the table, the present application realizes the synergy of A-level rolling resistance and anti-residue, wear resistance, among which Examples 5-6 are the optimal schemes, which can be directly applied to mainstream specifications such as 12R22.5 TBR tires, meeting the market demand for low-rolling-resistance and high-durability tires.

[0056] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary of the principles and application of the present application. Numerous modifications and changes can be made by those skilled in the art without departing from the spirit and principles of the present application.

Claims

1. A TBR tire tread composition with Class A rolling resistance and flaking properties, characterized in that, It is made from the following raw materials in parts by weight: 80 parts natural rubber, 20 parts solution-polymerized styrene-butadiene rubber, 15 parts N220 carbon black, 30 parts high-dispersion high-performance silica, 3 parts talc, 4 parts antioxidant, 7.8 parts modified silane coupling agent, 3.5 parts zinc oxide, 2 parts modified stearic acid, 2 parts processing aid, 2.5 parts accelerator, 1.8 parts sulfur, and 1.2 parts modified nanocellulose.

2. The TBR tire tread composition with Class A rolling resistance and flaking effect according to claim 1, characterized in that: The antioxidant comprises RD, 6PPD and microcrystalline wax, and the mass ratio of RD, 6PPD and microcrystalline wax is 2:2:

1.

3. The TBR tire tread composition with Class A rolling resistance and flaking effect according to claim 1, characterized in that: The modified silane coupling agent is prepared from a mixed silane containing a carbon black support, wherein the carbon black support accounts for 50% by mass, and the Si75 and Si69 in the mixed silane are combined in a 1:1 mass ratio. The specific modification process is as follows: The mixed silane containing carbon black support was dissolved in toluene, maleic anhydride was added, and the mixture was stirred and reacted at 80-90°C under nitrogen protection for 3-4 hours. After the reaction was completed, the toluene was removed by vacuum distillation to obtain the modified silane coupling agent. The amount of maleic anhydride added is 8% to 12% of the total mass of Si75 and Si69. The modified silane coupling agent has a maleic anhydride grafting rate of 5% to 8%.

4. The TBR tire tread composition with Class A rolling resistance and flaking effect according to claim 1, characterized in that: The modified stearic acid is produced by glycerol esterification of stearic acid. The specific modification process is as follows: Stearic acid and glycerol were mixed in a molar ratio of 2:1, and p-toluenesulfonic acid, accounting for 0.5% to 1% of the mass fraction of stearic acid, was added as a catalyst. The mixture was stirred at 120 to 130 °C for 2 to 3 hours to allow the carboxyl group of stearic acid to undergo an esterification reaction with the hydroxyl group of glycerol, generating a modified product mainly composed of glyceryl monostearate. After the reaction was completed, unreacted glycerol and catalyst were removed under reduced pressure to obtain the modified stearic acid. The modified stearic acid has an esterification degree of 85% to 90% and an acid value ≤ 5 mg KOH / g, wherein the modified stearic acid contains 3% to 8% unreacted stearic acid in its total amount.

5. The TBR tire tread composition with Class A rolling resistance and flaking effect according to claim 1, characterized in that: The modified nanocellulose is produced by citric acid esterification of microcrystalline cellulose. The specific modification process is as follows: Microcrystalline cellulose was dispersed in a 40%–50% (w / w) water-ethanol mixture and stirred at 1500–2000 rpm for 10–15 min to induce initial depolymerization. Citric acid (10%–15% (w / w)) was added, followed by anhydrous sodium carbonate (3%–5% (w / w)) of citric acid. The mixture was heated to 80–90°C and stirred at this constant temperature for 2.5–3.5 h to induce esterification between the carboxyl groups of citric acid and the hydroxyl groups on the surface of the microcrystalline cellulose, forming a carboxyl-modified layer on the surface of the nanocellulose. After the reaction, the mixture was separated by filtration. The resulting solid was washed with deionized water until neutral and then vacuum-dried at 70–80°C for 4–5 h to obtain the modified nanocellulose. The modified nanocellulose has a particle size of 10–50 nm and a degree of esterification of 12%–18%.

6. A method for preparing a TBR tire tread composition with Class A rolling resistance and flaking properties, characterized in that, The preparation of the TBR tire tread composition with Class A rolling resistance flaking as described in any one of claims 1 to 5 includes the following steps: S1. Add 80 parts of natural rubber and 20 parts of solution-polymerized styrene-butadiene rubber to an intermeshing internal mixer. Set the speed of the internal mixer to 55 rpm and mix for 25 seconds to soften the natural rubber. Then add 15 parts of N220 carbon black, 30 parts of highly dispersed high-performance silica, 4 parts of antioxidant, 2 parts of modified stearic acid, 3 parts of talc, 7.8 parts of modified silane coupling agent, 2 parts of processing aid, and 1.2 parts of modified nanocellulose. Continue mixing for 15 seconds, lifting the plug 2-3 times to vent and cool down. Each time the plug is lifted, the dwell time is 3-5 seconds. When the temperature of the material in the intermeshing internal mixer reaches 150℃, discharge the rubber to obtain a first-stage masterbatch. S2. Add the first stage of masterbatch obtained in step S1 and 3.5 parts of zinc oxide to the one-stage internal mixer. Set the speed of the one-stage internal mixer to 45 rpm. After mixing for 60 seconds, lift the plug and hold for 10 seconds. Then press the plug and continue mixing until the material temperature reaches 150°C. Discharge the rubber and transfer the discharged material to the open mill. Turn it over and cool it to 90-100°C. Then add 2.5 parts of accelerator and 1.8 parts of sulfur. Turn it over in a thin pass for 300 seconds. Finally, sheet it out and cool it to room temperature to obtain the final rubber. The final rubber is the A-grade rolling resistance slag-removing TBR tire tread composition.

7. The method for preparing a Class A rolling resistance flaking TBR tire tread composition according to claim 6, characterized in that: In step S1, the highly dispersed high-performance silica has a DBP absorption value of 185–230.0 mL / 100g, and the N220 silica has an iodine absorption value of 119–133 g / kg and a DBP absorption value of 108–120 × 10⁻⁶ g / kg. -5 m 3 / kg.

8. The method for preparing a Class A rolling resistance flaking TBR tire tread composition according to claim 6, characterized in that: In step S2, after the rubber is discharged, the material is conveyed to the open mill. During the turning and cooling process, the rubber material needs to be thinly passed through and formed into a ring on the cooling belt.

9. The method for preparing a Class A rolling resistance flaking TBR tire tread composition according to claim 6, characterized in that: In step S2, the initial temperature of the mixing chamber of the one-stage internal mixer is controlled at 60-70°C; the roll gap of the open mill is controlled at 3-5 mm.

10. The method for preparing a Class A rolling resistance flaking TBR tire tread composition according to claim 6, characterized in that: In step S2, the temperature of the open mill rolls is controlled not to exceed 100℃ during the thin-pass turning process; the number of thin-pass turnings is 5 to 8.

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