Tread rubber composition as well as preparation method and application thereof

Abstract

The invention discloses a tire tread rubber composition as well as a preparation method and application thereof. Based on 100 parts by mass of rubber, the rubber composition is prepared from 60-80 parts by mass of natural rubber, 20-40 parts by mass of solution polymerized styrene-butadiene rubber and 40-60 parts by mass of high-porosity white carbon black (LK100-R) modified by a difunctional coupling agent (3-((acryloyloxy) propyl) triethoxysilane (SAC). The LK100-R is obtained by firstly preparing high-porosity white carbon black (LK100) by adopting a sol-gel method in combination with supercritical drying and then carrying out graft modification on the surface of the high-porosity white carbon black (LK100) by utilizing SAC. By using the LK100-R, the dispersity of the filler in the rubber is remarkably improved, and the interface bonding of the filler and the rubber is enhanced, so that the obtained tread rubber material has excellent physical and mechanical properties, low heat generation, low rolling resistance and high wear resistance under the condition that a traditional silane coupling agent and a processing aid are not required to be added, meanwhile, the mixing process is simplified, and the production cost is reduced. And the production efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the field of tire rubber material technology, specifically relating to a tread rubber composition, its preparation method, and its application. Background Technology

[0002] Global climate change, energy security, and increasingly stringent environmental regulations (such as EU CO2 emission standards and tire labeling laws in various countries) have placed higher demands on the energy-saving and environmental performance of automobiles and tires. Reducing tire rolling resistance is one of the key ways to reduce vehicle fuel consumption and carbon emissions, and the development of low rolling resistance tires has become a mainstream trend in the industry.

[0003] Currently, common low rolling resistance and high wet grip tread formulations in the industry typically employ the following design: using solution-polymerized styrene-butadiene rubber (SSBR) with low hysteresis loss; introducing large-particle carbon black to reduce heat generation; and increasing the amount of silica to reduce hysteresis loss and improve wet grip performance. However, this approach has significant drawbacks: First, the strength of SSBR is generally lower than that of natural rubber; second, as the amount of silica increases, due to the large number of hydrophilic silanol groups on its surface, it is prone to agglomeration due to hydrogen bonding, leading to difficulties in dispersion within the rubber matrix. Poor filler dispersion severely affects the processing performance of the rubber compound (such as the appearance of the extruded semi-finished product), physical and mechanical properties, and abrasion resistance, and increases hysteresis loss due to the increased Payne effect, which is detrimental to reducing rolling resistance. Furthermore, insufficiently silanized silica can adsorb vulcanization accelerators, resulting in a slowdown in vulcanization speed. Traditional processes require the addition of silane coupling agents (such as Si-69) and prolonged high-temperature insulation during the mixing process to promote the silanization reaction. Small molecule additives such as processing oils and dispersants (such as PEG) are also required to improve processability and dispersibility. However, the presence of these small molecules may have an adverse effect on the performance of the final product (such as aging performance and dynamic performance).

[0004] Existing technologies such as CN1908076A, CN101792545A, and CN101113217A are all dedicated to improving the performance balance of tire tread compounds. However, how to simultaneously achieve excellent filler dispersion, high reinforcement, low heat generation, high wear resistance, and simplified processing when using high amounts of silica remains a technical challenge that needs to be solved in this field. Summary of the Invention

[0005] The primary objective of this invention is to overcome the shortcomings of the prior art and provide a tread rubber composition, its preparation method, and its application. This composition, while ensuring low rolling resistance, exhibits excellent filler dispersibility, physical and mechanical properties, and wear resistance.

[0006] One object of the present invention is to provide a tire tread rubber composition comprising the following raw materials in parts by weight: Natural rubber: 60-80 parts; Solution-polymerized styrene-butadiene rubber: 20-40 parts; (3-((acryloyloxy)propyl)triethoxysilane modified silica: 40-60 parts; Sulfur: 1.3–1.5 parts; Vulcanization accelerator: 1.3–1.5 parts; The total weight of natural rubber and solution-polymerized styrene-butadiene rubber is 100 parts. The CTAB specific surface area of ​​the (3-((acryloyloxy)propyl)triethoxysilane modified silica is 130~180 m2 / g, and the BET adsorption specific surface area is 260~360 m2 / g.

[0007] The solution-polymerized styrene-butadiene rubber has a styrene content of 10%-20% and a vinyl content of 20%-40%.

[0008] The sulfur / sulfurization accelerator has a weight percentage of 95% to 105%.

[0009] The preparation method of the (3-((acryloyloxy)propyl)triethoxysilane modified silica includes the following steps: a. Preparation of bifunctional coupling agent: 3-hydroxypropyltriethoxysilane and acryloyl chloride were esterified in an inert atmosphere and in the presence of a polymerization inhibitor at 0-5°C in the presence of an organic solvent and a base. After the reaction was completed, SAC was obtained by post-treatment. b. Preparation of high-porosity silica LK100: Using tetraethyl orthosilicate as the silicon source, the silica LK100 is obtained by hydrolysis and condensation under acidic conditions via sol-gel method. After gelation and solvent exchange, the silica is dried by supercritical CO2. c. Preparation of (3-((acryloyloxy)propyl)triethoxysilane modified silica: The SAC obtained in step a, ethanol and water were prepared into a modified solution, and LK100 obtained in step b was added. The mixture was stirred at 40°C for 4 hours, and then heated to 90°C for 2 hours. After the reaction was completed, the mixture was filtered, washed and dried to obtain (3-((acryloyloxy)propyl)triethoxysilane modified silica LK100-R) with acryloyl groups grafted on the surface.

[0010] In step a, the molar ratio of 3-hydroxypropyltriethoxysilane to acryloyl chloride is 1:1.0~1.2.

[0011] In step a, the base is triethylamine, and the molar ratio of triethylamine to acryloyl chloride is 0.6 ~ 0.8 : 1.

[0012] In step c, the modified solution is composed of 20 wt% SAC, 72 wt% ethanol and 8 wt% water; the mass ratio of LK100 to the modified solution is 1:1.

[0013] The invention also provides a method for preparing the tire tread rubber composition described above, comprising the following steps: First stage mixing: Add all materials except sulfur, vulcanization accelerator, scorch inhibitor, and (3-((acryloyloxy)propyl)triethoxysilane modified silica LK100-R) to the internal mixer, pressurize with the top plug for 20-40 seconds; remove the plug, add 50%-80% of (3-((acryloyloxy)propyl)triethoxysilane modified silica, pressurize with the top plug for 25-45 seconds; remove the plug, add the remaining 20%-50% of (3-((acryloyloxy)propyl)triethoxysilane modified silica, pressurize with the top plug for 25-45 seconds; remove the plug for 5-15 seconds; finally, pressurize and mix to 150℃-160℃ or for 120 seconds, then discharge the binder, sheet, and cool. Second stage of mixing: Put the first stage of mixed rubber into the internal mixer, pressurize with the top plug for 30-60 seconds, lift the plug for 5-15 seconds, and then pressurize to 150℃-160℃ or reach 100 seconds before discharging the rubber, extruding the sheet and cooling. Third stage of mixing: Put the second stage of mixed rubber into the internal mixer, pressurize with the top plug for 30-60 seconds, lift the plug for 5-15 seconds, and then pressurize and mix to 150℃-160℃ or after 100 seconds, discharge the rubber, sheet and cool. Fourth stage mixing: The third stage compound rubber, sulfur, vulcanization accelerator, and scorch inhibitor are put into the internal mixer. The top plug is pressed for 20-40 seconds, the top plug is lifted for 5-15 seconds, the pressure is increased for 20-40 seconds, the top plug is lifted for 5-15 seconds, the pressure is increased for 20-40 seconds, the top plug is lifted for 5-15 seconds, the pressure is increased again and the mixture is mixed to 105-125℃ or after 100 seconds, the rubber is discharged, the sheet is discharged and cooled.

[0014] The process parameters for each stage of mixing are as follows: Rotor speed: 35-55 rpm for the first stage of mixing, 40-55 rpm for the second stage of mixing, 40-55 rpm for the third stage of mixing, and 15-30 rpm for the fourth stage of mixing; Top bolt pressure: 85–125 bar; Cooling water pressure: ≥0.01 MPa.

[0015] One object of the present invention is the use of the tire tread rubber composition described herein in the manufacture of all-steel radial truck tire treads.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: Excellent performance: The (3-((acryloyloxy)propyl)triethoxysilane modified silica (LK100-R) used in this invention has high porosity, providing stronger reinforcing ability; the acryloyl groups on its surface can chemically bond with the double bonds of the rubber molecular chain through Michael addition, greatly enhancing the filler-rubber interface interaction. This allows the rubber compound to significantly improve its tensile stress, tensile strength, tear strength, rigidity, and abrasion resistance while maintaining low rolling resistance (low 60℃ Tanδ).

[0017] Good dispersibility: SAC modification changes the surface of silica from hydrophilic to hydrophobic, resulting in better compatibility with rubber, greatly inhibiting the agglomeration of silica, significantly reducing the Payne effect (ΔG'), and ensuring uniform dispersion of fillers.

[0018] Simplified Formulation: Since LK100-R has undergone silanization modification before compounding, there is no need to add traditional silane coupling agents (such as Si-69), processing oils (such as TDAE), and dispersants (such as PEG and Rhein 37) to the formulation. This reduces the migration and volatilization of small molecules, which is beneficial to the long-term performance stability and environmental friendliness of the product.

[0019] Process optimization: The mixing process eliminates the need for a long heat preservation stage to complete the silanization reaction, significantly shortening the first mixing time, improving mixing efficiency, and reducing energy consumption.

[0020] Wide range of applications: This technical solution has shown significant performance improvement in formulation systems with different ratios of natural rubber / styrene-butadiene rubber, and has wide applicability. Detailed Implementation

[0021] To facilitate understanding of the present invention, a more complete description is provided below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used in this invention includes any and all combinations of one or more of the associated listed items.

[0022] The present invention will be further described in detail below with reference to the embodiments and comparative examples shown in Tables 1-2, but the scope of protection of the present invention is not limited thereto.

[0023] Table 1

[0024] Table 2

[0025] The preparation method of (3-((acryloyloxy)propyl)triethoxysilane modified silica LK100-R) used in the examples and comparative examples is as follows: Preparation method of (3-((acryloyloxy)propyl)triethoxysilane (SAC) 1. Apparatus setup Place a dry 500mL three-necked flask in an ice-water bath. The three-necked flask should be equipped with: a constant-pressure dropping funnel, a reflux condenser (connected to a drying tube or tail gas absorption device to absorb HCl), a thermometer, and a nitrogen inlet. Add 100g (0.42mol) of 3-hydroxypropyltriethoxysilane and 150mL of anhydrous THF to the reaction flask. Start stirring and purge with nitrogen to purge air. Add the polymerization inhibitor (hydroquinone, 0.2-0.5g). Add triethylamine (46mL, 0.33mol).

[0026] 2. Dropping reaction Acryloyl chloride (38 mL, 0.46 mol) was mixed with an appropriate amount of anhydrous THF and added to a constant-pressure dropping funnel. Under ice bath cooling and vigorous stirring, the acryloyl chloride / THF solution was slowly added dropwise. The dropping rate was controlled to maintain the reaction temperature at 0–5 °C. After the addition was complete, the ice bath was removed, and the reaction mixture was allowed to slowly rise to room temperature while stirring continued for 4 hours.

[0027] 3. Post-processing After the reaction, a large amount of white solid (triethylamine hydrochloride) will remain in the solution. Filter using a sintered glass funnel or Buchner funnel to remove the solid salt, and wash the solid 2-3 times with a small amount of THF. Transfer the combined filtrate to a separatory funnel and wash successively with 5% sodium bicarbonate solution and saturated brine. Dry the organic phase overnight with anhydrous magnesium sulfate or sodium sulfate. Then filter to remove the drying agent, and evaporate most of the solvent THF using a rotary evaporator at low temperature (<40°C) under reduced pressure. Because the crude product may contain small amounts of unreacted raw materials, polymerization inhibitors, and solvents, high-vacuum fractionation is performed for further purification.

[0028] b. Preparation method of silica LK100 Step 1: Sol preparation 1. Mixing: Tetraethyl orthosilicate (TEOS), ethanol (EtOH) and deionized water are mixed in the reactor at a certain molar ratio (TEOS :EtOH : H2O = 1 : 4 : 10).

[0029] 2. Catalytic hydrolysis: Under vigorous stirring, add a small amount of acidic catalyst (hydrochloric acid) dropwise to adjust the pH value to 2-3.

[0030] 3. Constant temperature reaction: The mixture is stirred at 40°C for 2 hours to allow TEOS to be fully hydrolyzed, forming silica monomers and obtaining a transparent sol.

[0031] Step 2: Gelization 1. Injection molding and aging: The formed sol is injected into the mold and sealed.

[0032] 2. Formation of wet gel: Let stand at room temperature for 12 hours. During this period, the Si(OH)4 produced by hydrolysis will undergo a condensation reaction to form a three-dimensional Si-O-Si network structure. The solvent is encapsulated in the network to form a hard, transparent silica wet gel. Step 3: Solvent exchange 1. Remove the wet gel from the mold and soak it in a large amount of anhydrous ethanol.

[0033] 2. Replace the ethanol with fresh ethanol every 6 hours for 2 days. This process utilizes concentration diffusion to gradually replace the water in the gel pores with ethanol.

[0034] Step 4: Supercritical drying 1. Loading into the autoclave: Place the solvent-exchanged ethanol gel into an autoclave (supercritical dryer).

[0035] 2. Injection and pressurization: Inject liquid CO2 into the reactor and slowly pressurize it to the pressure required at room temperature (above 10 MPa) to bring the system into a supercritical state.

[0036] 3. Dynamic flushing: Under supercritical conditions, maintaining constant temperature and pressure, fresh CO2 is continuously introduced to dissolve and remove the ethanol from the reactor. This process takes 12-24 hours until all the ethanol is completely replaced.

[0037] 4. Slow pressure reduction: While maintaining the temperature above the critical temperature (31.1℃), reduce the pressure to atmospheric pressure very slowly (0.1-0.5 MPa per hour).

[0038] 5. Product Removal: Due to the absence of surface tension, the gel network structure remains intact. The final product is called silica aerogel, a type of precipitated silica with extremely high porosity.

[0039] Step 5: Post-processing and characterization 1. Collection: Remove the whole block or crushed into powder as needed from the autoclave.

[0040] 2. Characterization: The specific surface area and pore size distribution were determined using the CTAB and BET nitrogen adsorption methods.

[0041] c. LK100-R preparation method (R is CH2=CH-C(O)O-) Silica LK100 was added to a solution composed of SAC (20 wt%), ethanol (72 wt%), and water (8 wt%), wherein the mass ratio of LK100 to the solution was 1:1. The mixture was stirred at 40°C for 4 h, then the temperature was increased to 90°C and stirred for 2 h. After filtration, the mixture was washed with a large amount of anhydrous ethanol and dried to obtain high-porosity silica LK100-R with acryloyl groups grafted onto its surface.

[0042] Methods for preparing rubber in the examples and comparative examples Comparative Example 1 and Example 1 used a traditional silica formulation and heat preservation process, and the preparation method of internal mixer mixing is as follows: First stage of mixing: Add all materials except sulfur, vulcanization accelerator, scorch inhibitor, silica, and TDAE. Pressurize with the top plug for 30 seconds (20-40 seconds). Add 65% (50-80%) silica after lifting the plug. Pressurize with the top plug for 35 seconds (25-45 seconds). Add the remaining 35% (20-50%) silica after lifting the plug. Pressurize with the top plug for 100 seconds (90-110 seconds) or pressurize to 120°C. Then, inject TDAE oil after lifting the plug. Then pressurize to 145℃ and hold for 120 seconds (100-140 seconds), lift the plug for 10 seconds (5-15 seconds), press to 145℃ and hold for 120 seconds (100-140 seconds), lift the plug for 10 seconds (5-15 seconds), press to 145℃ and hold for 120 seconds (100-140 seconds), lift the plug for 10 seconds (5-15 seconds), then pressurize and mix for 120 seconds or to 155℃ (150-160℃) for glue discharge, sheeting and cooling; Second stage mixing: Add the first stage mixing rubber, apply pressure with the top bolt for 40 seconds (30 seconds to 60 seconds), lift the bolt for 10 seconds (5 seconds to 15 seconds), and mix under pressure for 100 seconds or until 155℃ (150℃ to 160℃) to discharge the rubber, sheet and cool. Third stage of mixing: Add the second stage of mixing rubber, apply pressure with the top bolt for 40 seconds (30 seconds to 60 seconds), lift the bolt for 10 seconds (5 seconds to 15 seconds), and mix under pressure for 100 seconds or until 155℃ (150℃ to 160℃) to discharge the rubber, sheet and cool. Fourth stage mixing: Add the third stage compound rubber, sulfur, vulcanization accelerator and anti-scorching agent, pressurize with the top plug for 30 seconds (20-40 seconds), lift the plug for 10 seconds (5-15 seconds), pressurize for 30 seconds (20-40 seconds), lift the plug for 10 seconds (5-15 seconds), pressurize for 30 seconds (20-40 seconds), lift the plug for 10 seconds (5-15 seconds), then pressurize and mix for another 100 seconds or until it reaches 115℃ (105℃-125℃) before discharging the rubber, extruding the sheet and cooling.

[0043] The above four stages of mixing: ➤ Rotor speed: First stage mixing: 45 rpm (35 rpm~55 rpm); Second stage mixing: 50 rpm (40 rpm~55 rpm); Third stage mixing: 50 rpm (40 rpm~55 rpm); Fourth stage mixing: 20 rpm (15 rpm~30 rpm); ➤ Top bolt pressure: 102 bar (85 bar ~ 125 bar); ➤ Cooling water pressure: ≥0.02Mpa (≥0.01Mpa).

[0044] Taking Examples 2 and 3 as examples, since the silica in the formulation has been surface modified in advance, the silane coupling agent Si-69 is removed from the formulation system. The internal mixer mixing preparation method, which has been verified multiple times, is provided as follows: First stage of mixing: Add all materials except sulfur, vulcanization accelerator, anti-scorching agent, and silica. Pressurize with the top plug for 30 seconds (20-40 seconds). Add 65% (50-80%) silica when the plug is lifted. Pressurize with the top plug for 35 seconds (25-45 seconds). Add the remaining 35% (20-50%) silica when the plug is lifted. Pressurize with the top plug for 35 seconds (25-45 seconds). Lift the plug for 10 seconds (5-15 seconds). Then pressurize and mix for another 120 seconds or until the temperature reaches 155℃ (150-160℃). Remove the glue, sheet, and cool. Second stage mixing: Add the first stage mixing rubber, apply pressure with the top bolt for 40 seconds (30 seconds to 60 seconds), lift the bolt for 10 seconds (5 seconds to 15 seconds), and mix under pressure for 100 seconds or until 155℃ (150℃ to 160℃) to discharge the rubber, sheet and cool. Third stage of mixing: Add the second stage of mixing rubber, apply pressure with the top bolt for 40 seconds (30 seconds to 60 seconds), lift the bolt for 10 seconds (5 seconds to 15 seconds), and mix under pressure for 100 seconds or until 155℃ (150℃ to 160℃) to discharge the rubber, sheet and cool. Fourth stage mixing: Add the third stage compound rubber, sulfur, vulcanization accelerator and anti-scorching agent, pressurize with the top plug for 30 seconds (20-40 seconds), lift the plug for 10 seconds (5-15 seconds), pressurize for 30 seconds (20-40 seconds), lift the plug for 10 seconds (5-15 seconds), pressurize for 30 seconds (20-40 seconds), lift the plug for 10 seconds (5-15 seconds), then pressurize and mix for another 100 seconds or until it reaches 115℃ (105℃-125℃) before discharging the rubber, extruding the sheet and cooling.

[0045] The above four stages of mixing: ➤ Rotor speed: First stage mixing: 45 rpm (35 rpm~55 rpm); Second stage mixing: 50 rpm (40 rpm~55 rpm); Third stage mixing: 50 rpm (40 rpm~55 rpm); Fourth stage mixing: 20 rpm (15 rpm~30 rpm); ➤ Top bolt pressure: 102 bar (85 bar ~ 125 bar); ➤ Cooling water pressure: ≥0.02Mpa (≥0.01Mpa).

[0046] It can be seen that, due to the early completion of the coupling reaction of modified silica, the first stage of mixing time in Examples 2 and 3 is significantly shortened compared with the baseline formula, thereby improving mixing efficiency and reducing manufacturing energy consumption.

[0047] Test data Performance tests were conducted on the embodiments and comparative examples, and the specific test conditions and standards were as follows: 1. Scorch time: The scorch time of the rubber sample sheet was measured at 127℃ in accordance with GB / T 1233-2008.

[0048] 2. Rheological Data: Rheological data were measured using an ALPHA MDR2000 rotorless vulcanizer (USA) at 151℃ for 60 minutes, in accordance with GB / T 16584-1996. The vulcanization reversion rate was calculated using the following formula: Vulcanization reversion rate = (Ffinal - FL) / (Fmax - FL), where Ffinal is the final torque or force (N·m or N), Fmax is the maximum torque or force during the test (N·m or N), and FL is the minimum torque or force (N·m or N).

[0049] 3. Payne Effect: Test the ΔG' of uncured rubber according to ASTM D6204.

[0050] 4. Bound Rubber: According to enterprise standard TC-10-02-282, weigh approximately 0.5g of the compound rubber and record its mass W1. Cut it into small pieces of approximately 1mm³. First, wrap the compound rubber with a nickel mesh of mass W2, which has been pre-dried in a vacuum oven at 35℃. Place the mesh in a beaker, add 100ml of toluene, and seal the beaker with sealing film to prevent solvent evaporation. Soak at room temperature for 48 hours, then replace the solvent and soak for another 24 hours. Remove the mesh and dry it at room temperature for several hours. Then, dry it in a vacuum oven at 35℃ until constant weight, with a mass of W3. Calculate the bound rubber mass using the following formula: Bound Rubber = (W3 - W2 - W1 × filler mass fraction in the compound rubber) / (W1 × rubber mass fraction in the compound rubber) × 100%.

[0051] 5. Shore hardness: The Shore hardness of the rubber sample sheet shall be measured at 25℃ in accordance with GB / T 531.1-2008.

[0052] 6. The modulus of M100, modulus of M300, tensile strength and elongation at break shall be measured in accordance with GB / T 528-2009 (using a rubber specimen with a dumbbell-shaped specimen).

[0053] 7. tanδ and E': According to ISO 4664-1:2005, the loss tangent tanδ and stiffness E' of a 2mm thick rubber sample were measured using a GABOMETER 2000 Dynamic Mechanical Analyzer (DMA) manufactured by GABO GmbH, Germany, at an initial strain of 10%, a dynamic strain of 5%, and a frequency of 10Hz. tanδ at 60℃ is related to the heat generation properties of the rubber; the smaller the tanδ value at 60℃, the lower the heat generation. E' characterizes the stiffness of the rubber; the larger the E' at 60℃, the smaller the deformation of the rubber under the same conditions.

[0054] 8. Lamborn Wear: Following ISO 23337-2016, a Ueshima AB-1152 Lamborn tester was used. Input parameters included a force F=40N to simulate tire load; the linear velocity of the wear wheel was 80m / min; the slip ratio was set to 30%; and the linear velocity of the sample wheel was 56m / min. The sample wheel was weighed before operation and again after 48 seconds of operation. The wear volume was converted to density. Using the wear performance of Comparative Example 1 as 100, the wear performance of the examples was converted into an index; a higher index indicates better wear performance.

[0055] The properties of the comparative and example rubber compounds prepared using the above internal mixer mixing process are shown in Table 3.

[0056] Table 3

[0057] The rolling resistance test results for finished tires are shown in Table 4.

[0058] Table 4

[0059] As shown in Table 3, compared with Comparative Example 1, Example 1 showed worse filler dispersion, but improved rubber properties, modulus, physical and mechanical properties, and rigidity of the compound (5%-E'). It also showed increased hysteresis loss (60℃-Tanδ). This indicates that high-porosity silica has better reinforcing performance, but generates more heat.

[0060] Example 2 uses surface-treated high-porosity silica, which can further improve the binding rubber, modulus, physical and mechanical properties, and rigidity of the rubber compound (5%-E'), while also exhibiting good dispersion and a significant decrease in hysteresis loss (60℃-Tanδ).

[0061] Example 3 removes processing aids such as TDAE, PEG, and Rhein 37 from Example 2. This is because the agglomeration effect is greatly reduced after the surface treatment of silica, allowing the removal of filler-dispersing processing aids. The reduction of small molecules in the formulation can further improve the rubber's binding properties, modulus, physical and mechanical properties, and rigidity (5%-E'), which helps ensure the tire's appearance during use, such as groove bottom cracks and chipping. At the same time, reducing hysteresis loss (60℃-Tanδ) can effectively reduce tire rolling resistance and significantly improve wear performance.

[0062] As can be seen from Table 4, the tire rolling resistance of Example 3 is significantly reduced compared to the baseline formulation, Example 1, and Example 2.

[0063] The properties of the rubber compounds in Comparative Examples 2-3 and Examples 4-5 are shown in Table 5.

[0064] Table 5

[0065] Referring to Table 2, the proportions of natural rubber and solution-polymerized styrene-butadiene rubber SLR3402 in Comparative Example 1 were adjusted to obtain Comparative Examples 2 and 3. Based on Comparative Example 2, silica 195GR was replaced with LK100-R, and processing oil and small molecules used for the silanization reaction were removed to obtain Example 4. Based on Comparative Example 3, silica 195GR was replaced with LK100-R, and processing oil and small molecules used for the silanization reaction were removed to obtain Example 5.

[0066] As shown in Table 5, the payne effect of Example 4 compared to Comparative Example 2, and Example 5 compared to Comparative Example 3, was significantly reduced. This indicates better filler dispersion, significantly improved physical and mechanical properties of the compound, a significant reduction in hysteresis loss (60℃-Tanδ), and a substantial improvement in abrasion performance. This demonstrates that modified silica LK100-R can be applied to different formulation systems, significantly improving filler dispersion, physical and mechanical properties, and abrasion performance, while substantially reducing heat generation.

[0067] This invention synthesizes high-porosity silica LK100 using a reaction vessel apparatus. Furthermore, it modifies LK100 with synthesized (3-((acryloyloxy)propyl)triethoxysilane (SAC) to obtain modified silica LK100-R. This modified silica exhibits a hydrophobic surface, significantly enhancing its compatibility with rubber and eliminating the need for processing oils and other additives. The modified silica surface contains acryloyl groups, which can react with double bonds in the rubber molecular chain via Michael addition, greatly improving the interaction between the filler and the rubber. Simultaneously, the early completion of the silanization reaction eliminates the need for adding silane coupling agents and other small molecules to supplement the silanization reaction during rubber compounding, further improving the physical and mechanical properties and abrasion resistance of the rubber compound. In short, this invention provides a low rolling resistance tire tread rubber composition and its preparation method that exhibit low hysteresis loss, high rigidity, excellent physical and mechanical properties, good abrasion resistance, and good processability.

[0068] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A tire tread rubber composition, characterized in that, Including the following parts by weight of raw materials: Natural rubber: 60-80 parts; Solution-polymerized styrene-butadiene rubber: 20-40 parts; (3-((acryloyloxy)propyl)triethoxysilane modified silica: 40-60 parts; Sulfur: 1.3–1.5 parts; Vulcanization accelerator: 1.3–1.5 parts; The total weight of natural rubber and solution-polymerized styrene-butadiene rubber is 100 parts. The CTAB specific surface area of ​​the (3-((acryloyloxy)propyl)triethoxysilane modified silica is 130~180 m². 2 / g, BET adsorption specific surface area is 260~360 m² 2 / g.

2. The tire tread rubber composition according to claim 1, characterized in that, The solution-polymerized styrene-butadiene rubber has a styrene content of 10%-20% and a vinyl content of 20%-40%.

3. The tire tread rubber composition according to claim 1, characterized in that, The sulfur / sulfurization accelerator has a weight percentage of 95% to 105%.

4. The tire tread rubber composition according to claim 1, characterized in that, The preparation method of the (3-((acryloyloxy)propyl)triethoxysilane modified silica includes the following steps: a. Preparation of bifunctional coupling agent: In the presence of an inert atmosphere and a polymerization inhibitor, 3-hydroxypropyltriethoxysilane and acryloyl chloride are subjected to an esterification reaction at 0-5°C in the presence of an organic solvent and a base. After the reaction is completed, (3-((acryloyloxy)propyl)triethoxysilane is obtained by post-treatment. b. Preparation of high-porosity silica LK100: Using tetraethyl orthosilicate as the silicon source, the silica LK100 is obtained by hydrolysis and condensation under acidic conditions via sol-gel method. After gelation and solvent exchange, the silica is dried by supercritical CO2. c. Preparation of (3-((acryloyloxy)propyl)triethoxysilane modified silica: The (3-((acryloyloxy)propyl)triethoxysilane) obtained in step a, ethanol and water were prepared into a modified solution, and the high-porosity silica LK100 obtained in step b was added. The mixture was stirred at 40°C for 4 hours, and then heated to 90°C for 2 hours. After the reaction was completed, the mixture was filtered, washed and dried to obtain (3-((acryloyloxy)propyl)triethoxysilane) modified silica LK100-R with acryloyl groups grafted on the surface.

5. The tire tread rubber composition according to claim 4, characterized in that, In step a, the molar ratio of 3-hydroxypropyltriethoxysilane to acryloyl chloride is 1:1.0~1.

2.

6. The tire tread rubber composition according to claim 4, characterized in that, In step a, the base is triethylamine, and the molar ratio of triethylamine to acryloyl chloride is 0.6 ~ 0.8 :

1.

7. The tire tread rubber composition according to claim 4, characterized in that, In step c, the modified solution consists of 20 wt% SAC, 72 wt% ethanol and 8 wt% water; the mass ratio of LK100 to the modified solution is 1:

1.

8. A method for preparing the tire tread rubber composition as described in claim 1, characterized in that, Includes the following steps: First stage mixing: Add all materials except sulfur, vulcanization accelerator, scorch inhibitor, and (3-((acryloyloxy)propyl)triethoxysilane modified silica LK100-R) to the internal mixer, pressurize with the top plug for 20-40 seconds; remove the plug, add 50%-80% of (3-((acryloyloxy)propyl)triethoxysilane modified silica, pressurize with the top plug for 25-45 seconds; remove the plug, add the remaining 20%-50% of (3-((acryloyloxy)propyl)triethoxysilane modified silica, pressurize with the top plug for 25-45 seconds; remove the plug for 5-15 seconds; finally, pressurize and mix to 150℃-160℃ or for 120 seconds, then discharge the binder, sheet, and cool. Second stage of mixing: Put the first stage of mixed rubber into the internal mixer, pressurize with the top plug for 30-60 seconds, lift the plug for 5-15 seconds, and then pressurize to 150℃-160℃ or reach 100 seconds before discharging the rubber, extruding the sheet and cooling. Third stage of mixing: Put the second stage of mixed rubber into the internal mixer, pressurize with the top plug for 30-60 seconds, lift the plug for 5-15 seconds, and then pressurize and mix to 150℃-160℃ or after 100 seconds, discharge the rubber, sheet and cool. Fourth stage mixing: The third stage compound rubber, sulfur, vulcanization accelerator, and scorch inhibitor are put into the internal mixer. The top plug is pressed for 20-40 seconds, the top plug is lifted for 5-15 seconds, the pressure is increased for 20-40 seconds, the top plug is lifted for 5-15 seconds, the pressure is increased for 20-40 seconds, the top plug is lifted for 5-15 seconds, the pressure is increased again and the mixture is mixed to 105-125℃ or after 100 seconds, the rubber is discharged, the sheet is discharged and cooled.

9. The preparation method according to claim 8, characterized in that, The process parameters for each stage of mixing are as follows: Rotor speed: 35-55 rpm for the first stage of mixing, 40-55 rpm for the second stage of mixing, 40-55 rpm for the third stage of mixing, and 15-30 rpm for the fourth stage of mixing; Top bolt pressure: 85–125 bar; Cooling water pressure: ≥0.01 MPa.

10. The use of the tire tread rubber composition according to claim 1 or 2 in the manufacture of all-steel radial truck tire treads.

Images