Wear-resistant tire tread rubber material and preparation method thereof

Abstract

The invention discloses a wear-resistant tire tread rubber material and a preparation method thereof, and relates to the technical field of tire materials, the wear-resistant tire tread rubber material comprises the following components: 100.0 parts of a rubber matrix, 20-60 parts of solution polymerized styrene-butadiene rubber, 40-95 parts of emulsion polymerized styrene-butadiene rubber, and 10-30 parts of butadiene rubber; the BET (Brunauer, Emmett and Teller) specific surface area is 90-150m < 2 > / g, and the DBP (Dibutyl Phosphate) absorption value is 100-160ml / 100g; 2-15 parts of low PAHs operation oil, wherein the aromatic hydrocarbon content is less than or equal to 3%; the composite protective wax is composed of low-temperature wax with the content of more than or equal to 50% and high-temperature wax according to the weight ratio of 1: 1 to 1: 2; a vulcanization system: 1.2 to 3.5 parts of sulfur, 1.0 to 2.0 parts of an accelerant NS, and 0.5 to 1.0 part of an accelerant DPG; according to the wear-resistant and wear-resistant rubber disclosed by the invention, by virtue of a high SSBR ratio, superfine carbon black gradient filling and a three-section mixing process, the wet-skid performance and the wear resistance are balanced, and meanwhile, environmental protection laws and regulations and processing requirements are met.

Description

Technical Field

[0001] The present invention relates to the technical field of tire materials, and particularly to a wear-resistant tire tread compound and a preparation method thereof. Background Art

[0002] Due to the demands of the domestic and international taxi markets, wear-resistant tires have always occupied an important segment of the market. Wear-resistant tires in the mainstream market suffer from the problem of insufficient wet grip, especially in rainy regions. The development focus of wear-resistant tire tread compounds is to improve the wet grip of tires under the condition of ensuring that the mileage is not affected.

[0003] Generally, in order to meet the long driving mileage of the tread compound, the amounts of cis-polybutadiene rubber and reinforcing agent are increased in the formulation design, but the consequent problem is the reduction of wet skid performance. Insufficient wet skid performance, especially under rainy or slippery road surface conditions, leads to a sharp decrease in tire grip, resulting in an extended braking distance and potential safety hazards.

[0004] As described above, the current wear-resistant tire technology faces two major contradictions: the conflict between high wear resistance requirements and wet skid performance, and the compatibility contradiction between material property improvement and processing technology. There is an urgent need for an innovative formulation and process to significantly improve wet skid safety performance while ensuring extremely long driving mileage and meeting the requirements of environmental protection regulations. Summary of the Invention

[0005] The present invention provides a wear-resistant tire tread compound and a preparation method thereof to solve the above problems existing in the prior art.

[0006] The present invention provides a wear-resistant tire tread compound, comprising:

[0007] 100.0 parts of a rubber matrix, composed of 20 - 60 parts of solution styrene-butadiene rubber (SSBR), 40 - 95 parts of emulsion styrene-butadiene rubber (E-SBR), and 10 - 30 parts of cis-polybutadiene rubber (BR);

[0008] 50 - 80 parts of an ultra-fine carbon black reinforcing filler, with a BET specific surface area of 90 - 150 m 2 / g and a DBP absorption value of 100 - 160 ml / 100 g;

[0009] 2 - 15 parts of a low-PAHs processing oil, with an aromatic content of ≤ 3%;

[0010] 1 - 2.5 parts of a composite protective wax, composed of a low-temperature wax (with a C26 - C29 content ≥ 50%) and a high-temperature wax (with a C30 - C32 content ≥ 30%) in a weight ratio of 1:1 to 1:2;

[0011] A vulcanization system: 1.2 - 3.5 parts of sulfur, 1.0 - 2.0 parts of accelerator NS, and 0.5 - 1.0 part of accelerator DPG;

[0012] Auxiliary components: 3 - 8 parts of zinc oxide, 1 - 3 parts of stearic acid, 2 - 4.5 parts of antioxidant, 0.1 - 0.4 parts of scorch retarder.

[0013] Optionally, the ultrafine carbon black is at least one of N134, N220 or N234, and the particle size distribution D50 ≤ 30 nm.

[0014] Optionally, the content of isoparaffin in the composite protective wax ≥ 25%, and the content of C26 - C27 in the low - temperature wax is 14 - 24 wt%, and the content of C28 - C29 is 15 - 25 wt%.

[0015] Optionally, the low - PAHs processing oil is TDAE or HNAP, the antioxidant is a mixture of antioxidant RD and antioxidant 4020, with a weight ratio of 1:1 to 1:2, and the weight ratio of accelerator NS to DPG is 2:1 to 4:1.

[0016] Optionally, the addition of the reinforcing filler is carried out in two stages. In the first stage, 60 - 80% of the total carbon black is added, and in the second stage, the remaining 20 - 40% is added. The tanδ of the vulcanized rubber compound at 0℃ ≥ 0.28, the tanδ at 60℃ ≤ 0.16, and the Akron abrasion ≤ 0.13 cm 3 / 1.61 km.

[0017] On the other hand, the present invention also provides a method for preparing a wear - resistant tire tread rubber compound. The method includes the following steps:

[0018] (1) Preparation of the first - stage masterbatch: Adjust the speed of the internal mixer to 40 - 60 r / min, put in the rubber matrix, 60 - 80% of the ultrafine carbon black, zinc oxide and stearic acid, mix for 20 - 40 seconds, add the low - PAHs processing oil, reduce the speed to 35 - 55 r / min, and continue to mix until the temperature reaches 160 - 170℃, then discharge the rubber to obtain the first - stage masterbatch;

[0019] (2) Preparation of the second - stage masterbatch: Put the first - stage masterbatch, the remaining 20 - 40% of the ultrafine carbon black, antioxidant, and composite protective wax into the internal mixer, with a speed of 45 - 55 r / min, mix until the temperature reaches 160 - 170℃, and discharge the rubber to obtain the second - stage masterbatch;

[0020] (3) Preparation of the final masterbatch: Put the second - stage masterbatch, sulfur, accelerator, and scorch retarder into the internal mixer, with a speed of 25 - 40 r / min, mix until discharging at 100 - 115℃, and obtain the tread rubber compound after sheeting on a two - roll mill and cooling.

[0021] Optionally, in step (1), the mixing temperature is 165 ± 5℃, and the mixing time ≤ 40 seconds.

[0022] Optionally, in step (2), the antioxidant is a mixture of antioxidant RD and 4020, which is added to the internal mixer in two portions.

[0023] Optionally, in step (3), sulfur is added in the form of insoluble sulfur, with a content of 1.5 - 2.5 parts.

[0024] Optionally, after the final rubber compound is discharged from the mill, it is sheeted out by a twin - screw extruder, and the extrusion pressure is 10 - 15 MPa.

[0025] The present invention has the following beneficial effects compared with the prior art:

[0026] In this solution, through the dynamic blending of a high - proportion solution - polymerized styrene - butadiene rubber and cis - 1,4 - polybutadiene (BR), a rigid - flexible segment synergistic network is formed, which raises the tanδ value at 0 °C to 0.28 - 0.30 (compared with 0.25 - 0.26 for traditional rubber compounds), and shortens the wet braking distance by 12 - 15%; in the step - by - step gradient filling process of ultra - fine carbon black (N134 / N220 / N234), the carbon black dispersion degree reaches grade 9 (ISO11345 standard), the internal stress distribution of the rubber compound is uniform, and the fluctuation of the wet skid performance is reduced by 30%. The high reinforcing effect of ultra - fine carbon black (BET≥90m 2 / g) and the high cut - resistance of SSBR act synergistically, and the Akron abrasion is stabilized at 0.11 - 0.13 cm 3 / 1.61 km, which is more than 20% higher than the traditional formula. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0028] Figure 1 It is a flowchart of the preparation method of a wear - resistant tire tread rubber compound of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The following will clearly and completely describe the technical solutions of the present invention in combination with the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0030] Unless otherwise specified, the raw materials used in the present invention are all conventional products purchased from the market.

[0031] Example 1

[0032] 50.0 parts of solution-polymerized styrene-butadiene rubber SSBR2550, 46.25 parts of emulsion-polymerized styrene-butadiene rubber SBR1723, 30.0 parts of cis-butadiene rubber BR9000, 80.0 parts of carbon black N134, 13.0 parts of low-PAHs processing oil TDAE, 3.5 parts of zinc oxide, 2.5 parts of stearic acid, 2.5 parts of antioxidant 4020, 1.5 parts of antioxidant RD, 1.5 parts of compound protective wax, 1.8 parts of sulfur I S7020, 1.3 parts of accelerator NS, 0.8 parts of accelerator DPG, 0.2 parts of scorch retarder CTP.

[0033] Put 50.0 parts of solution-polymerized styrene-butadiene rubber SSBR2550, 46.25 parts of emulsion-polymerized styrene-butadiene rubber SBR1723, and 30.0 parts of cis-butadiene rubber BR9000 into an F370 internal mixer, set the initial speed at 50 RPM and mix for 20 seconds; after lifting the upper ram, put in 60.0 parts of carbon black N134 (75% of the total 80.0 parts), 3.5 parts of zinc oxide, 2.5 parts of stearic acid, 2.5 parts of antioxidant 4020, 1.5 parts of antioxidant RD, and 1.5 parts of compound protective wax, reduce the speed to 45 RPM and press the ram (0.6 MPa) and mix until 120 °C; inject 13.0 parts of low-PAHs processing oil TDAE, continue to mix until the temperature reaches 165 °C, then discharge the rubber to a twin-screw extruder to make sheets (thickness 10 mm), and cool to below 40 °C; put the first-stage masterbatch and the remaining 20.0 parts of carbon black N134 into the internal mixer, mix at 50 RPM for 30 seconds until 165 °C, and extrude and make sheets (thickness 8 mm); in the final mixing stage, put the second-stage masterbatch into a Banbury internal mixer, add 1.8 parts of sulfur I S7020, 1.3 parts of accelerator NS, 0.8 parts of DPG, and 0.2 parts of scorch retarder CTP, mix at 30 RPM until discharging at 108 °C, and vulcanize after making sheets on a two-roll mill (150 °C × 30 minutes).

[0034] Example 2

[0035] 60.0 parts of solution-polymerized styrene-butadiene rubber SSBR2550, 40.0 parts of emulsion-polymerized styrene-butadiene rubber SBR1723, 20.0 parts of cis-butadiene rubber BR9000, 75.0 parts of carbon black N220, 7.0 parts of low-PAHs processing oil HNAP, 3.5 parts of zinc oxide, 2.0 parts of stearic acid, 2.0 parts of antioxidant 4020, 1.0 parts of antioxidant RD, 2.0 parts of compound protective wax, 1.7 parts of sulfur I S7020, 1.5 parts of accelerator NS, 0.7 parts of accelerator DPG, 0.2 parts of scorch retarder CTP.

[0036] 60.0 parts of solution-polymerized butadiene styrene rubber SSBR2550, 40.0 parts of emulsion-polymerized butadiene styrene rubber SBR1723, and 20.0 parts of butadiene rubber BR9000 were put into an internal mixer, mixed at 55 RPM for 20 seconds, and then 56.25 parts of carbon black N220 (75% of the total 75.0 parts), 3.5 parts of zinc oxide, and 2.0 parts of stearic acid were added; 4.0 parts of low-PAHs operating oil HNAP were injected, mixed to a temperature of 170°C, and then the rubber was discharged and cooled; a masterbatch was mixed with the remaining carbon black N22018.75 parts, antioxidant 40202.0 parts, RD 1.0 parts, and composite protective wax 2.0 parts at 55 RPM for 25 seconds to 170°C; sulfur IS70201.7 parts, accelerator NS1.5 parts, DPG 0.7 parts, and anti-scorch agent CTP were added in the final mixing stage. 0.2 parts, mixed to 110℃ for rubber discharge, after vulcanization, the tanδ of the rubber at 0℃ reaches 0.293.

[0037] Example 3

[0038] Solution polymerized butadiene styrene rubber SSBR255070.0 parts, emulsion polymerized butadiene styrene rubber SBR172363.75 parts, butadiene rubber BR900010.0 parts, carbon black N23470.0 parts, low PAHs operating oil HNAP 2.0 parts, zinc oxide 3.0 parts, stearic acid 1.5 parts, antioxidant 40202.0 parts, antioxidant RD 2.0 parts, composite protective wax 1.5 parts, sulfur IS70201.5 parts, accelerator NS1.8 parts, accelerator DPG 0.5 parts, anti-scorch agent CTP 0.2 parts.

[0039] 70.0 parts of solution-polymerized butadiene styrene rubber SSBR2550, 3.75 parts of emulsion-polymerized butadiene styrene rubber SBR17236, and 10.0 parts of butadiene rubber BR9000 were put into an internal mixer, mixed at 45RPM for 20 seconds, and then 2.5 parts of carbon black N2345 (75% of the total 70.0 parts), 3.0 parts of zinc oxide, and 1.5 parts of stearic acid were added twice; 2.0 parts of low-PAHs operating oil HNAP were injected at one time, and mixed to 160℃ for rubber discharge; a masterbatch was mixed with the remaining carbon black N23417.5 parts, antioxidant 40202.0 parts, RD 2.0 parts, and composite protective wax 1.5 parts at 50RPM to 165℃, and the carbon black dispersion reached 9.5 levels; 1.5 parts of sulfur IS7020, 1.8 parts of accelerator NS, 0.5 parts of DPG, and anti-scorch agent CTP were added in the final mixing stage. 0.2 parts, mixed to 102℃, the Akron abrasion after vulcanization is 0.105cm 3 / km

[0040] Comparative Example 1

[0041] 82.5 parts of emulsion-polymerized styrene-butadiene rubber SBR1723, 40.0 parts of cis-1,4-polybutadiene rubber BR9000, 85.0 parts of carbon black N220, 18.0 parts of highly aromatic oil TDAE, 3.0 parts of zinc oxide, 2.0 parts of stearic acid, 2.0 parts of antioxidant 4020, 1.0 part of antioxidant RD, 1.5 parts of ordinary protective wax, 1.9 parts of ordinary sulfur, 1.1 parts of accelerator NS, 0.6 part of accelerator DPG, 0.2 part of scorch retarder CTP.

[0042] Put 82.5 parts of emulsion-polymerized styrene-butadiene rubber SBR1723 and 40.0 parts of cis-1,4-polybutadiene rubber BR9000 into an internal mixer. After kneading at 60 RPM for 40 seconds, add 63.75 parts of carbon black N220 (75% of the total 85.0 parts), 3.0 parts of zinc oxide, 2.0 parts of stearic acid, 2.0 parts of antioxidant 4020, 1.0 part of RD and 1.5 parts of ordinary protective wax at one time; inject 18.0 parts of highly aromatic oil TDAE, and discharge the rubber when the temperature reaches 170°C; in the final kneading stage, add 1.9 parts of ordinary sulfur, 1.1 parts of accelerator NS, 0.6 part of DPG and 0.2 part of scorch retarder CTP, knead until the temperature reaches 120°C and discharge the rubber. After vulcanization, the tanδ at 0°C is only 0.254.

[0043] Furthermore, in Examples 1-3, two-stage carbon black addition and staged kneading were adopted. Through (primary masterbatch and secondary masterbatch), the carbon black dispersion degree reached above 9.0 levels; in Comparative Example 1, all the carbon black was added at one time, and the dispersion degree was only 8.3 levels. In Examples 1-3, the discharge temperature at the final kneading stage was ≤115°C, and sulfur was added in the form of insoluble sulfur (IS7020) to avoid scorching; in Comparative Example 1, the discharge temperature reached 120°C, and ordinary sulfur was likely to cause early vulcanization.

[0044] Table 1 - Formulations of Examples 1-3 and Comparative Example 1

[0045]

[0046]

[0047] Table 2 - Physical Properties of the Rubber Compounds of Examples 1-3 and Comparative Example 1

[0048]

[0049]

[0050] As can be seen from Table 2, after increasing the amount of styrene-butadiene in the wear-resistant tread rubber, the wet skid performance of the tread can be significantly improved. A typical data is that the value of tanδ at 0°C increases from 0.254 of the comparative value to about 0.280. The wet skid performance is tested by a DMA testing machine for tanδ at 0°C, and the larger the reported value, the higher the wet skid performance. In addition, the abrasion of the example compound does not change significantly. The present invention achieves a balance between wet skid performance and wear resistance through a high proportion of SSBR, gradient filling of ultra-fine carbon black, and a three-stage mixing process, while meeting environmental regulations and processing requirements.

[0051] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A wear-resistant tire tread compound, characterized in that, It comprises the following components by weight parts: 100.0 parts of rubber matrix, which consists of 20 - 60 parts of solution-polymerized styrene-butadiene rubber, 40 - 95 parts of emulsion-polymerized styrene-butadiene rubber, and 10 - 30 parts of cis-butadiene rubber; 50 - 80 parts of ultra-fine carbon black reinforcing filler, BET specific surface area 90 - 150 m 2 / g, DBP absorption value 100 - 160 ml / 100 g; 2 - 15 parts of low-PAHs process oil, with the aromatic content ≤ 3%; 1 - 2.5 parts of composite protective wax, which consists of low-temperature wax and high-temperature wax in a weight ratio of 1:1 to 1:2; Vulcanization system: 1.2 - 3.5 parts of sulfur, 1.0 - 2.0 parts of accelerator NS, and 0.5 - 1.0 parts of accelerator DPG; Auxiliary components: 3 - 8 parts of zinc oxide, 1 - 3 parts of stearic acid, 2 - 4.5 parts of antioxidant, and 0.1 - 0.4 parts of scorch retarder.

2. The rubber compound according to claim 1, wherein, The ultrafine carbon black is at least one of N134, N220, or N234, and the particle size distribution D50 ≤ 30 nm.

3. The rubber compound according to claim 1, wherein The isoparaffin content in the composite protective wax ≥ 25%, and the C26 - C27 content of the low-temperature wax is 14 - 24 wt%, and the C28 - C29 content is 15 - 25 wt%.

4. The rubber compound according to claim 1, characterized in that, The low-PAHs process oil is TDAE or HNAP, the antioxidant is a mixture of antioxidant RD and antioxidant 4020 with a weight ratio of 1:1 to 1:2, and the weight ratio of accelerator NS to DPG is 2:1 to 4:

1.

5. The rubber compound according to claim 1, wherein, The addition of the reinforcing filler is carried out in two stages. In the first stage, 60-80% of the total carbon black is added, and in the second stage, the remaining 20-40% is added. The tanδ of the vulcanizate at 0°C ≥ 0.28, the tanδ at 60°C ≤ 0.16, and the Akron abrasion ≤ 0.13 cm 3 / 1.61 km.

6. A method for preparing the wear-resistant tire tread rubber compound according to any one of claims 1-5, characterized in that, It includes the following steps: (1) Preparation of the first-stage masterbatch: Adjust the speed of the internal mixer to 40 - 60 r / min, put in the rubber matrix, 60 - 80% of the ultrafine carbon black, zinc oxide, and stearic acid, knead for 20 - 40 seconds, add the low-PAHs process oil, reduce the speed to 35 - 55 r / min, and continue kneading until the temperature reaches 160 - 170 °C, then discharge the rubber to obtain the first-stage masterbatch; (2) Preparation of the second-stage masterbatch: Put the first-stage masterbatch, the remaining 20 - 40% of the ultrafine carbon black, antioxidant, and composite protective wax into the internal mixer, with a speed of 45 - 55 r / min, knead until the temperature reaches 160 - 170 °C, and discharge the rubber to obtain the second-stage masterbatch; (3) Preparation of the final masterbatch: Put the second-stage masterbatch, sulfur, accelerator, and scorch retarder into the internal mixer, with a speed of 25 - 40 r / min, knead until discharging at 100 - 115 °C, and roll out the sheet through a two-roll mill, and obtain the tread stock after cooling.

7. The preparation method according to claim 6, characterized in that, In step (1), the kneading temperature is 165 ± 5 °C, and the kneading time ≤ 40 seconds.

8. As described in the preparation method of claim 6, in step (2), the antioxidant is a mixture of antioxidant RD and 4020, and is added to the internal mixer in two times.

9. The preparation method according to claim 6, characterized in that, In step (3), sulfur is added in the form of insoluble sulfur, with a content of 1.5 - 2.5 parts.

10. The preparation method according to claim 6, characterized in that, After the final masterbatch is discharged, it is rolled out through a twin-screw extruder, and the extrusion pressure is 10 - 15 MPa.

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