All-steel snow tire tread and its preparation method

Abstract

The present invention provides a steel radial snow tire tread and a preparation method thereof. The raw materials thereof, by weight parts, consist of: 50 - 80 parts of natural rubber, 20 - 50 parts of solution styrene-butadiene rubber with double glass transition temperatures, 40 - 60 parts of carbon black, 10 - 20 parts of white carbon black with high specific surface area, 1 - 2.5 parts of silane coupling agent, 5 - 10 parts of modified anti-hydroplaning resin, 2 - 5 parts of zinc oxide, 1 - 3 parts of stearic acid, 1 - 3 parts of antioxidant 4020, 1 - 3 parts of antioxidant RD, 1 - 3 parts of protective wax, 1 - 1.8 parts of sulfur, and 1 - 1.5 parts of accelerator NS. The prepared steel radial snow tire tread compound has two glass transition temperatures. The first glass transition temperature ≤ -60 °C, which meets the use requirements in severe cold regions; -40 °C ≤ the second glass transition temperature ≤ -20 °C, with excellent anti-hydroplaning performance and snow and ice road grip performance. At the same time, the heat generation is reduced, and the wear resistance is improved by more than 20% compared with the existing steel radial snow tire products, meeting the use requirements of the tire in severe cold regions and the high-performance use requirements of fuel saving and high wear resistance mileage after winter or when driving across regions to non-severe cold regions.

Description

Technical Field

[0001] The invention relates to the technical field of all-steel snow tires, and in particular to an all-steel snow tire tread and a preparation method thereof. Background Art

[0002] With the development of the tire industry and the upgrading and iteration of technology, the market segmentation and demand diversification of tires are also increasing. In areas with low temperatures and snowy weather all year round, the use of winter tires is gaining more and more attention from car users. Winter tires are mainly used in low temperatures and on icy and snowy roads, which requires the hardness of the tire tread rubber at low temperatures to be lower than that of ordinary tires, and it must have excellent ice and snow grip performance to improve the tire's maneuverability and ensure driving safety. Unlike semi-steel snow tires, all-steel snow tires have a large load capacity and wear quickly, and most users will not change tires after winter and continue to use snow tires. It can be seen that all-steel snow tires not only need to have good anti-slip and ice and snow road grip, but also need excellent wear resistance and low rolling resistance to meet the high-performance requirements of long tire service life and low fuel consumption.

[0003] In the prior art, when designing the tread formula of all-steel snow tires, a certain amount of cis-butadiene rubber is usually used in the natural rubber system. The glass transition temperature Tg of cis-butadiene rubber is -100°C, which is the synthetic rubber with the best cold resistance. It can reduce the hardening degree of the tread rubber at low temperatures and increase the contact area between the tire tread and the ground, but the anti-slip ability of cis-butadiene rubber is poor. In order to further improve the anti-slip performance of the tread rubber when designing the tread formula of all-steel snow tires, patents CN105086005B and CN105037824B use solution-polymerized styrene-butadiene rubber with a Tg close to that of natural rubber, or use oil-filled neodymium-based cis-butadiene rubber with a lower Tg, and add highly dispersed white carbon black commonly used in semi-steel snow tires. The prepared tread rubber has moderate hardness, good elasticity, and excellent anti-slip performance in severe cold and snow.

[0004] Compared with cis-1,4-butadiene rubber, the combined use of solution-polymerized styrene-butadiene rubber, which has a Tg close to that of natural rubber, can improve the tread ice grip (tanδ@-25℃) and wet grip (tanδ@0℃), but it will also increase the heat generation of the rubber (tanδ@60℃), resulting in increased tire rolling resistance; the specific surface area of ​​highly dispersed silica is relatively small and it is easy to disperse in the rubber matrix, but its reinforcement of rubber is insufficient, and there is still much room for improvement in the wear resistance of the tire. Summary of the invention

[0005] The invention provides an all-steel snow tire tread and a preparation method thereof, so as to solve the defects in the prior art.

[0006] On the one hand, the present invention provides a tread for all-steel snow tires, which is composed of the following raw materials in parts by weight: 50-80 parts of natural rubber, 20-50 parts of solution-polymerized styrene-butadiene rubber with a dual glass transition temperature, 40-60 parts of carbon black, 10-20 parts of high specific surface area silica, 1-2.5 parts of silane coupling agent, 5-10 parts of modified anti-wet skid resin, 2-5 parts of zinc oxide, 1-3 parts of stearic acid, 1-3 parts of antioxidant 4020, 1-3 parts of antioxidant RD, 1-3 parts of protective wax, 1-1.8 parts of sulfur, and 1-1.5 parts of accelerator NS.

[0007] According to the tread for all-steel snow tires provided by the present invention, the solution-polymerized styrene-butadiene rubber with a dual glass transition temperature has a dual glass transition temperature, the first Tg is less than -70 °C, the second Tg ranges from -55 °C to -35 °C, and the peak value of its loss factor is lower than that of ordinary solution-polymerized styrene-butadiene rubber with a single glass transition temperature and a low glass transition temperature.

[0008] According to the tread for all-steel snow tires provided by the present invention, the carbon black is N115 or N220.

[0009] According to the tread for all-steel snow tires provided by the present invention, the high specific surface area silica has a specific surface area of 220-300 m 2 / g as measured by BET, and a dibutyl phthalate absorption value of 250-300 cm 3 / 100 g.

[0010] According to the tread for all-steel snow tires provided by the present invention, the silane coupling agent is Si-75, and the weight ratio of it to the high specific surface area silica is 1:10 - 1.4:10.

[0011] According to the tread for all-steel snow tires provided by the present invention, the modified anti-wet resin is a copolymer resin of modified styrene and dicyclopentadiene.

[0012] According to the tread for all-steel snow tires provided by the present invention, the preparation method of the tread for all-steel snow tires is carried out according to the following steps:

[0013] (a) Put natural rubber, solution-polymerized styrene-butadiene rubber with a dual glass transition temperature, part of carbon black, high specific surface area silica, and silane coupling agent into an internal mixer and mix for 40-50 s, the rotational speed of the internal mixer is 40-55 rpm, the pressure of the upper ram is 45-55 N / cm 2 , lift the upper ram 2 times, each time for 5-15 s, and discharge the rubber and make a sheet when the mixing temperature is 150-155 °C to obtain a first-stage masterbatch;

[0014] (b) Put a section of masterbatch rubber and the remaining carbon black, zinc oxide, stearic acid, modified anti-wet skid resin, antioxidant 4020, antioxidant RD, and protective wax into a mixer and knead for 10 - 30 s. The mixer speed is 45 - 50 rpm, and the upper plug pressure is 45 - 55 N / cm 2 , and discharge the rubber and sheet it when the kneading temperature is 155 - 165 °C to obtain the second-stage masterbatch rubber;

[0015] (c) Put the second-stage masterbatch rubber, sulfur, and accelerator NS into a mixer and knead for 20 - 30 s. The mixer speed is 20 - 25 rpm, and the upper plug pressure is 40 - 45 N / cm 2 , and discharge the rubber and sheet it when the kneading temperature is 100 - 110 °C to obtain the tread rubber.

[0016] The all-steel snow tire tread and its preparation method provided by the present invention have the following technical effects: The prepared all-steel snow tread rubber has two glass transition temperatures. The first glass transition temperature ≤ -60 °C, meeting the use requirements in severe cold regions; -40 °C ≤ the second glass transition temperature ≤ -20 °C, with low modulus at low temperatures, excellent anti-wet skid performance and ice and snow road grip performance. At the same time, the heat generation is reduced, and the wear resistance is improved by more than 20% compared with existing all-steel snow tire products, far meeting the index requirements of ECE-R117 regulations for tire rolling resistance, snow traction index, and wet traction index, meeting the use requirements of tires in severe cold regions and the high-performance use requirements for fuel saving and high wear resistance mileage after winter or when traveling across regions to non-severe cold regions.

[0017] 1. Use solution styrene-butadiene rubber with dual glass transition temperatures (Tg). The first Tg of the solution styrene-butadiene rubber is less than -70 °C, and the second Tg temperature range is -55 °C to -35 °C, and the peak value of the loss factor is lower than that of low-Tg solution styrene-butadiene rubber with ordinary single glass transition temperature, enabling the all-steel snow tread rubber to have two glass transition temperatures, with moderate hardness at low temperatures, low elastic modulus at -25 °C, high loss factor tanδ value at 0 °C, and low loss factor tanδ value at 60 °C, taking into account high ice and snow grip, anti-wet skid performance, and low heat generation performance.

[0018] 2. Use high specific surface area white carbon black with a BET specific surface area of 220 - 300 m2 / g and a dibutyl phthalate absorption value of 250 - 300 cm3 / 100 g. Through the adjustment of components and the optimization of the ratio with silane coupling agent Si75, while improving the puncture of the water film to ensure grip on wet and ice and snow ground, the wear resistance is significantly improved compared with the tread rubber compound using low specific surface area highly dispersed white carbon black and is close to the tread rubber filled with pure carbon black.

[0019] 3. Using a modified styrene and dicyclopentadiene copolymer resin, the resin has excellent compatibility with rubber, which can improve the wet skid resistance of the tread compound and simultaneously reduce the rolling resistance. While ensuring the excellent ice and snow grip of all-steel snow tires, the rolling resistance is further reduced and the wear resistance is significantly improved, which can greatly meet the safety requirements of truck and bus users when using in low-temperature ice and snow areas, as well as the high-performance requirements of low fuel consumption and high wear resistance of the tires when driving to non-severe cold areas after winter or across regions.

[0020] Through the application of solution-polymerized styrene-butadiene rubber with double glass transition temperatures, high specific surface area silica, modified styrene and dicyclopentadiene copolymer resin and the optimization of the ratio of each component, the all-steel tread compound prepared by mixing and production has a low elastic modulus at low temperatures, strong grip on ice, snow and wet ground, and low rolling resistance; the wear resistance is increased by more than 20%, meeting the use requirements of tires in severe cold regions, as well as the fuel-saving and high-mileage use requirements of users when they do not replace the snow tires after winter or when driving to non-severe cold regions; it solves the problem that currently, the tread rubber of tires has insufficient reinforcement and the wear resistance of tires needs to be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in 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 some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0022] Figure 1 It is the DMA temperature scanning curve of the tread compounds prepared in Comparative Example 1 and Example 4 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] The following will further describe in detail the specific embodiments of the present invention in conjunction with the embodiments. The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of the present invention.

[0024] In order to better understand the purpose of the present invention, the following will further describe the present invention in detail.

[0025] A tread of an all-steel snow tire according to an embodiment of the present application is composed of the following raw materials in parts by weight: 50-80 parts of natural rubber, 20-50 parts of solution-polymerized styrene-butadiene rubber with a dual glass transition temperature, 40-60 parts of carbon black, 10-20 parts of white carbon black with a high specific surface area, 1-2.5 parts of silane coupling agent, 5-10 parts of modified anti-wet skid resin, 2-5 parts of zinc oxide, 1-3 parts of stearic acid, 1-3 parts of antioxidant 4020, 1-3 parts of antioxidant RD, 1-3 parts of protective wax, 1-1.8 parts of sulfur, and 1-1.5 parts of accelerator NS.

[0026] To further optimize the above technical solution, the solution-polymerized styrene-butadiene rubber with a dual glass transition temperature has a dual glass transition temperature, the first Tg is less than -70 °C, the second Tg temperature range is -55 °C to -35 °C, and the peak value of its loss factor is lower than that of ordinary solution-polymerized styrene-butadiene rubber with a single glass transition temperature and a low glass transition temperature.

[0027] To further optimize the above technical solution, the carbon black is N115 or N220.

[0028] To further optimize the above technical solution, the white carbon black with a high specific surface area has a specific surface area of 220-300 m 2 / g as measured by BET, and the dibutyl phthalate absorption value is 250-300 cm 3 / 100 g.

[0029] To further optimize the above technical solution, the silane coupling agent is Si-75, and the weight ratio of it to the white carbon black with a high specific surface area is 1:10 - 1.4:10.

[0030] To further optimize the above technical solution, the modified anti-wet resin is a copolymer resin of modified styrene and dicyclopentadiene.

[0031] To further optimize the above technical solution, the preparation method of the tread of the all-steel snow tire is carried out according to the following steps:

[0032] (a) Put 70 parts of natural rubber, 30 parts of solution-polymerized styrene-butadiene rubber with a dual glass transition temperature, part of the carbon black, white carbon black with a high specific surface area, and silane coupling agent into an internal mixer and knead for 40-50 s. The speed of the internal mixer is 40-55 rpm, and the pressure of the upper plug is 45-55 N / cm 2 , lift the upper plug 2 times, each time for 5-15 s, and discharge the rubber and take out the sheet when the kneading temperature is 150-155 °C to obtain a first-stage masterbatch;

[0033] (b) Put the first-stage masterbatch and the remaining carbon black, zinc oxide, stearic acid, modified anti-wet skid resin, antioxidant 4020, antioxidant RD, and protective wax into an internal mixer and knead for 10-30 s. The speed of the internal mixer is 45-50 rpm, and the pressure of the upper plug is 45-55 N / cm2 When the mixing temperature is 155 - 165 °C, the rubber is discharged and sheeted to obtain the second-stage masterbatch.

[0034] (c) Put the second-stage masterbatch, sulfur, and accelerator NS into a mixer and mix for 20 - 30 s. The mixer speed is 20 - 25 rpm, and the upper plug pressure is 40 - 45 N / cm 2 When the mixing temperature is 100 - 110 °C, the rubber is discharged and sheeted to obtain the tread rubber.

[0035] Example 1

[0036] Put 70 parts of natural rubber, 30 parts of solution-polymerized styrene-butadiene rubber with double glass transition temperatures, 25 parts of carbon black, 15 parts of highly dispersed silica, and 1.2 parts of silane coupling agent into a mixer and mix for 45 s. The mixer speed is 50 rpm, and the upper plug pressure is 50 N / cm 2 Lift the upper plug 2 times, each time for 10 s. When the mixing temperature is 150 °C, the rubber is discharged and sheeted to obtain the first-stage masterbatch.

[0037] Put the first-stage masterbatch, 25 parts of carbon black, 3 parts of zinc oxide, 2 parts of stearic acid, 5 parts of anti-slip resin, 1.5 parts of antioxidant 4020, 1.5 parts of antioxidant RD, and 1.5 parts of protective wax into a mixer and mix for 20 s. The mixer speed is 45 rpm, and the upper plug pressure is 50 N / cm 2 When the mixing temperature is 155 - 165 °C, the rubber is discharged and sheeted to obtain the second-stage masterbatch.

[0038] Put the second-stage masterbatch, 1.5 parts of sulfur, and 1.3 parts of accelerator NS into a mixer and mix for 25 s. The mixer speed is 22 rpm, and the upper plug pressure is 42 N / cm 2 When the mixing temperature is 105 °C, the rubber is discharged and sheeted to obtain the tread rubber.

[0039] Example 2

[0040] Put 70 parts of natural rubber, 30 parts of solution-polymerized styrene-butadiene rubber with double glass transition temperatures, 25 parts of carbon black, 15 parts of high specific surface area silica, and 1.5 parts of silane coupling agent into a mixer and mix for 45 s. The mixer speed is 50 rpm, and the upper plug pressure is 50 N / cm 2 Lift the upper plug 2 times, each time for 10 s. When the mixing temperature is 150 °C, the rubber is discharged and sheeted to obtain the first-stage masterbatch.

[0041] Put the first-stage masterbatch, 25 parts of carbon black, 3 parts of zinc oxide, 2 parts of stearic acid, 5 parts of anti-slip resin, 1.5 parts of antioxidant 4020, 1.5 parts of antioxidant RD, and 1.5 parts of protective wax into a mixer and mix for 20 s. The mixer speed is 45 rpm, and the upper plug pressure is 50 N / cm 2 When the mixing temperature is 160 °C, the rubber is discharged and sheeted to obtain the second-stage masterbatch.

[0042] Put 2-stage masterbatch, 1.5 parts of sulfur, and 1.4 parts of accelerator NS into the internal mixer and knead for 25 s. The rotational speed of the internal mixer is 23 rpm, and the pressure of the upper ram is 42 N / cm 2 , and discharge the rubber and sheet it out at a kneading temperature of 105 °C to obtain the tread rubber.

[0043] Example 3

[0044] Put 70 parts of natural rubber, 30 parts of solution-polymerized styrene-butadiene rubber with double glass transition temperatures, 25 parts of carbon black, 15 parts of high specific surface area white carbon black, and 1.5 parts of silane coupling agent into the internal mixer and knead for 45 s. The rotational speed of the internal mixer is 50 rpm, and the pressure of the upper ram is 50 N / cm 2 , lift the upper ram 2 times, keep it for 10 s each time, and discharge the rubber and sheet it out at a kneading temperature of 150 °C to obtain the 1-stage masterbatch;

[0045] Put the 1-stage masterbatch, 25 parts of carbon black, 3 parts of zinc oxide, 2 parts of stearic acid, 5 parts of modified anti-wet skid resin, 1.5 parts of antioxidant 4020, 1.5 parts of antioxidant RD, and 1.5 parts of protective wax into the internal mixer and knead for 20 s. The rotational speed of the internal mixer is 45 rpm, and the pressure of the upper ram is 50 N / cm 2 , and discharge the rubber and sheet it out at a kneading temperature of 160 °C to obtain the 2-stage masterbatch;

[0046] Put the 2-stage masterbatch, 1.5 parts of sulfur, and 1.4 parts of accelerator NS into the internal mixer and knead for 25 s. The rotational speed of the internal mixer is 22 rpm, and the pressure of the upper ram is 42 N / cm 2 , and discharge the rubber and sheet it out at a kneading temperature of 105 °C to obtain the tread rubber.

[0047] Example 4

[0048] Put 60 parts of natural rubber, 40 parts of solution-polymerized styrene-butadiene rubber with double glass transition temperatures, 23 parts of carbon black, 20 parts of high specific surface area white carbon black, and 2.4 parts of silane coupling agent into the internal mixer and knead for 45 s. The rotational speed of the internal mixer is 50 rpm, and the pressure of the upper ram is 50 N / cm 2 , lift the upper ram 2 times, keep it for 10 s each time, and discharge the rubber and sheet it out at a kneading temperature of 150 °C to obtain the 1-stage masterbatch;

[0049] Put the 1-stage masterbatch, 23 parts of carbon black, 3 parts of zinc oxide, 2 parts of stearic acid, 8 parts of modified anti-wet skid resin, 1.5 parts of antioxidant 4020, 1.5 parts of antioxidant RD, and 1.5 parts of protective wax into the internal mixer and knead for 10 - 30 s. The rotational speed of the internal mixer is 45 rpm, and the pressure of the upper ram is 50 N / cm 2 , and discharge the rubber and sheet it out at a kneading temperature of 160 °C to obtain the 2-stage masterbatch;

[0050] Put 2-stage masterbatch, 1.4 parts of sulfur, and 1.5 parts of accelerator NS into the internal mixer and knead for 25 s. The rotational speed of the internal mixer is 22 rpm, and the upper plug pressure is 42 N / cm 2 , and discharge the rubber and sheet it out to obtain tread rubber when the kneading temperature is 105 °C.

[0051] Example 5

[0052] Put 50 parts of natural rubber, 50 parts of solution-polymerized styrene-butadiene rubber with double glass transition temperatures, 21 parts of carbon black, 20 parts of high specific surface area white carbon black, and 2.4 parts of silane coupling agent into the internal mixer and knead for 45 s. The rotational speed of the internal mixer is 50 rpm, and the upper plug pressure is 50 N / cm 2 , lift the upper plug 2 times, each time for 10 s, and discharge the rubber and sheet it out to obtain 1-stage masterbatch when the kneading temperature is 150 °C;

[0053] Put 1-stage masterbatch, 21 parts of carbon black, 3 parts of zinc oxide, 2 parts of stearic acid, 10 parts of modified anti-wet skid resin, 1.5 parts of antioxidant 4020, 1.5 parts of antioxidant RD, and 1.5 parts of protective wax into the internal mixer and knead for 20 s. The rotational speed of the internal mixer is 45 rpm, and the upper plug pressure is 50 N / cm 2 , and discharge the rubber and sheet it out to obtain 2-stage masterbatch when the kneading temperature is 160 °C;

[0054] Put 2-stage masterbatch, 1.4 parts of sulfur, and 1.5 parts of accelerator NS into the internal mixer and knead for 25 s. The rotational speed of the internal mixer is 22 rpm, and the upper plug pressure is 42 N / cm 2 , and discharge the rubber and sheet it out to obtain tread rubber when the kneading temperature is 105 °C.

[0055] Comparative Example 1

[0056] Put 70 parts of natural rubber, 30 parts of solution-polymerized styrene-butadiene rubber with low glass transition temperature, 25 parts of carbon black, 15 parts of highly dispersed white carbon black, and 1.2 parts of silane coupling agent into the internal mixer and knead for 45 s. The rotational speed of the internal mixer is 50 rpm, and the upper plug pressure is 50 N / cm 2 , lift the upper plug 2 times, each time for 10 s, and discharge the rubber and sheet it out to obtain 1-stage masterbatch when the kneading temperature is 150 °C;

[0057] Put 1-stage masterbatch, 25 parts of carbon black, 3 parts of zinc oxide, 2 parts of stearic acid, 5 parts of anti-wet skid resin, 1.5 parts of antioxidant 4020, 1.5 parts of antioxidant RD, and 1.5 parts of protective wax into the internal mixer and knead for 20 s. The rotational speed of the internal mixer is 45 rpm, and the upper plug pressure is 50 N / cm 2 , and discharge the rubber and sheet it out to obtain 2-stage masterbatch when the kneading temperature is 160 °C;

[0058] Put 2-stage masterbatch, 1.5 parts of sulfur, and 1.3 parts of accelerator NS into the internal mixer and knead for 25 s. The rotational speed of the internal mixer is 22 rpm, and the upper plug pressure is 42 N / cm2 When the mixing temperature is 105 °C, the stock is discharged and sheeted to obtain the tread rubber.

[0059] Table 1 Composition of Comparative Example 1 and Examples 1-5

[0060]

[0061]

[0062] The tread rubber with the composition specified in Table 1 is prepared in a BR Banbury mixer. The preparation process involves three separate feeding and mixing stages, namely, two non-productive mixing stages and one productive mixing stage. The two non-productive stages are each mixed for about 2 - 3 minutes until the rubber temperature reaches 150 - 155 °C and 155 - 165 °C respectively, at which point they are completed. The productive stage is mixed for about 1 - 1.5 minutes until the rubber temperature reaches 100 - 110 °C, at which point it is completed.

[0063] Table 2 Mechanical and Physical Properties of Comparative Example 1 and Examples 1-5

[0064]

[0065] Table 2 shows the physical and mechanical properties of the above comparative examples and examples. Each property of the rubber compound was tested according to national or industry standards. The vulcanization conditions of the rubber compound were 151 °C × 30 min. Among them, the dynamic mechanical properties were characterized by temperature scanning of the vulcanized rubber using a dynamic viscoelastic spectrometer (DMA) produced by GABO Company of Germany. The test conditions were: compression mode, frequency 10 Hz, static strain 5%, dynamic strain 0.2%, temperature range -70 - 70 °C, heating rate 2 °C / min.

[0066] Generally, the ice and snow traction is characterized by the elastic modulus E' at -25 °C. The lower the value, the lower the modulus and the better the ice and snow traction performance. The wet skid resistance is characterized by tanδ at 0 °C. The higher the value, the stronger the wet skid resistance. The heat generation performance of the rubber compound is characterized by tanδ at 60 °C. The lower the value, the lower the heat generation of the rubber compound, that is, the lower the rolling resistance of the tire.

[0067] From Table 2 and Figure 1It can be seen that the solution-polymerized styrene-butadiene rubber with a low peak double glass transition temperature Tg can adjust the Tg of the tread compound and the peak shape of the DMA curve, reduce the Tg of the tread compound, increase the tanδ at -25°C and 0°C, reduce the E' at -25°C, reduce the tanδ at 60°C, improve the ice and snow grip and wet skid resistance of the tread compound, and reduce heat generation and improve wear resistance; the high specific surface area silica can pierce the water film, provide wet skid resistance, enhance the reinforcement performance of the rubber, and significantly improve the wear resistance compared with the high-dispersion silica; the modified styrene and dicyclopentadiene copolymer resin can improve the wet skid resistance and reduce the rolling resistance.

[0068] Table 3 Performance test data of the tread compounds of Comparative Example 1 and Examples 3 - 44 for trial production of 12R22.5 full-steel snow tires

[0069]

[0070] Table 3 gives the performance test data of the 12R22.5 full-steel snow tires trial-produced using the tread compounds of Comparative Example 1 and Examples 3 - 4. The rolling resistance of the tires was tested in the national engineering laboratory, the snow performance was tested at the Heilongjiang Red River Valley Automobile Test Center in accordance with the ECE-R117 regulation, and the wear performance of the tires was tested in accordance with GB / T 29041-2012.

[0071] As can be seen from Table 3, the full-steel snow tires produced with the tread compounds prepared in Examples 3 and 4 have obvious advantages in terms of rolling resistance, wet skid performance, snow performance, wear resistance, etc., and can make the performance indicators of the tread compound reach the optimal balance value.

[0072] In summary, through the application of the solution-polymerized styrene-butadiene rubber with double glass transition temperatures, high specific surface area silica, modified styrene and dicyclopentadiene copolymer resin and the optimization of the ratio of each component, the all-steel tread compound prepared by mixing and production has two glass transition temperatures. The first glass transition temperature ≤ -60°C, meeting the use requirements in severe cold regions; -40°C ≤ the second glass transition temperature ≤ -20°C, with a low elastic modulus at low temperatures, strong grip on ice and snow and in wet conditions, and low rolling resistance, far exceeding the index requirements of the ECE-R117 regulation for tire rolling resistance and snow and wet grip indices; the wear resistance is improved by more than 20%, meeting the use requirements of tires in severe cold regions, and the fuel-saving and high-mileage use requirements when users do not replace the snow tires after winter or when driving to non-severe cold regions.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A tread of an all-steel snow tire, characterized in that, it is composed of the following raw materials by weight parts: 50-80 parts of natural rubber, 20-50 parts of solution-polymerized styrene-butadiene rubber with double glass transition temperatures, 40-60 parts of carbon black, 10-20 parts of high specific surface area silica, 1-2.5 parts of silane coupling agent, 5-10 parts of modified anti-wet skid resin, 2-5 parts of zinc oxide, 1-3 parts of stearic acid, 1-3 parts of antioxidant 4020, 1-3 parts of antioxidant RD, 1-3 parts of protective wax, 1-1.8 parts of sulfur, 1-1.5 parts of accelerator NS; the carbon black is N115 or N220; The specific surface area of the high specific surface area silica is measured by BET to be 220 - 300 m 2 / g, and the dibutyl phthalate absorption value is 250 - 300 cm 3 / 100 g; the silane coupling agent is Si-75, and the weight part ratio thereof to the high specific surface area silica is 1:10 - 1.4:10; the modified anti-wet resin is a modified styrene and dicyclopentadiene copolymer resin; the preparation method of the tread of the all-steel snow tire is carried out according to the following steps: (a) Natural rubber, solution-polymerized styrene-butadiene rubber with double glass transition temperatures, partial carbon black, high specific surface area silica, and a silane coupling agent are put into an internal mixer and kneaded for 40 - 50 s. The rotational speed of the internal mixer is 40 - 55 rpm, and the upper plug pressure is 45 - 55 N / cm 2 , the upper plug is lifted twice, each time for 5 - 15 s, and the stock is discharged and sheeted out when the kneading temperature is 150 - 155 °C to obtain a first-stage masterbatch; (b) Put a section of masterbatch and the remaining carbon black, zinc oxide, stearic acid, modified anti-wet skid resin, antioxidant 4020, antioxidant RD, and protective wax into an internal mixer and knead for 10 - 30 s. The rotational speed of the internal mixer is 45 - 50 rpm, and the upper plug pressure is 45 - 55 N / cm 2 , and discharge the rubber and cut it into sheets at a kneading temperature of 155 - 165 °C to obtain the second-stage masterbatch; (c) Put the two-stage masterbatch, sulfur, and accelerator NS into the internal mixer and knead for 20 - 30 s. The rotational speed of the internal mixer is 20 - 25 rpm, and the pressure of the upper plug is 40 - 45 N / cm 2 , and discharge the rubber and take out the sheet at a kneading temperature of 100 - 110 °C to obtain the tread rubber; the solution-polymerized styrene-butadiene rubber with double glass transition temperatures has double glass transition temperatures, the first Tg is less than -70 °C, the second Tg temperature range is -55 °C to -35 °C, and the peak value of its loss factor is lower than that of ordinary solution-polymerized styrene-butadiene rubber with a single glass transition temperature and a low glass transition temperature.

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