All-steel driving tire tread rubber and preparation method thereof

Abstract

The invention provides all-steel driving tire tread rubber and a preparation method of the all-steel driving tire tread rubber. The tread rubber comprises the following components: 20-60 parts of natural rubber, 20-60 parts of smoke sheet rubber, 20-40 parts of rare earth butadiene rubber, 5-35 parts of white carbon black, 20-60 parts of reinforcing carbon black, 2-5 parts of zinc oxide, 2-5 parts of stearic acid, 2-6 parts of an anti-aging agent, 0.5-3 parts of protective wax, 1-3.5 parts of a silane coupling agent, 1-3 parts of a physical plasticizer, 0.5-2 parts of an accelerant NS, 0.5-2 parts of sulfur powder and 0.1-0.5 part of a scorch retarder CTP. The long-distance tread rubber disclosed by the invention can meet the basic properties such as hardness, tear resistance and wear resistance of long-distance tread rubber, and can meet the use conditions of low-temperature flexibility, wet skid resistance, ice skid resistance, environment-friendly compliance and low rolling resistance in rainy and snowy weather in Europe, and the selection of materials also needs to conform to Europe environment-friendly and safety standards.

Description

Technical Field

[0001] The present invention relates to the technical field of rubber, and particularly to a tread rubber for all-steel drive tires and a preparation method thereof. Background Art

[0002] With the prosperous development of the world's tire technology, the performance requirements for all-steel tires in the European market are getting higher and higher. Lower rolling resistance, higher wear resistance, and better anti-hydroplaning performance are the development directions of vehicles in the European market in recent years. All along, the research direction of tires in the European market has always revolved around two dimensions: improving anti-hydroplaning performance and reducing heat generation. However, for all-steel tires used in snowy and rainy areas in Europe, only considering improving anti-hydroplaning performance and reducing tire heat generation is far from enough.

[0003] The existing methods for improving the wear resistance of rubber compounds mainly focus on adding cis-butadiene rubber with excellent low-temperature performance and using carbon black with a high specific surface area. However, limited by the performance of the materials themselves, there is still an obvious problem of hardening of the rubber compound at low temperatures. At the same time, there is a large gap in the anti-cutting performance between cis-butadiene rubber and natural rubber and styrene-butadiene rubber. While improving the wear resistance of the tread, it will cause a significant decrease in the cut resistance of the tread. Using this method to solve the problem of tire wear resistance in cold regions is not a long-term solution. Therefore, it has become an urgent problem to provide a tread rubber that has both anti-cutting performance and anti-crack and anti-blocking performance at low temperatures and at the same time has excellent wear resistance. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies existing in the prior art and provide a tread rubber for all-steel drive tires and a preparation method thereof. The rare-earth catalyzed cis-butadiene rubber used in the present invention can provide good flexibility for the rubber compound at temperatures below minus ten degrees Celsius while improving the wear resistance. The tread rubber for all-steel drive tires prepared by this method has good elasticity and elongation at break at low temperatures, excellent cut resistance, and good wear resistance, and is suitable for use in snowy and rainy areas in Europe.

[0005] To achieve the above technical purposes, the technical solutions adopted in the embodiments of the present invention are as follows: In the first aspect, the embodiments of the present invention provide a tread rubber for all-steel drive tires, which includes the following components in parts by weight: 20-60 parts of natural rubber, 20-60 parts of smoked sheet rubber, 20-40 parts of rare-earth cis-butadiene rubber, 5-35 parts of silica, 20-60 parts of reinforcing carbon black, 2-5 parts of zinc oxide, 2-5 parts of stearic acid, 2-6 parts of antioxidant, 0.5-3 parts of protective wax, 1-3.5 parts of silane coupling agent, 1-3 parts of physical plasticizer, 0.5-2 parts of accelerator NS, 0.5-2 parts of sulfur powder, and 0.1-0.5 parts of anti-scorching agent CTP; Among them, the total of the natural rubber, smoked sheet rubber, and rare-earth cis-butadiene rubber is 100 parts.

[0006] Furthermore, the smoked sheet rubber is cis-1,4-polyisoprene.

[0007] Furthermore, the rare earth cis-polybutadiene rubber is neodymium-based polybutadiene rubber with a cis content higher than 96% and no oil filling; The neodymium-based polybutadiene rubber is cis-1,4-polybutadiene rubber prepared by solution polymerization of butadiene under a neodymium-based catalyst system.

[0008] Furthermore, the white carbon black is HD175MP or 1165MP with a specific surface area of 160 - 180 m 2 / g; The silane coupling agent is liquid Si69 or Si75.

[0009] Furthermore, the reinforcing carbon black includes at least one of N134 and BL101.

[0010] Furthermore, the antiozonant includes 1.5 - 3.5 parts of p-phenylenediamine antiozonant 4020 and 0.5 - 2.5 parts of ketoamine antiozonant RD.

[0011] Furthermore, the protective wax is bimodal microcrystalline wax or trimodal microcrystalline wax.

[0012] Furthermore, the physical plasticizer is a mixture of fatty acid zinc soaps, with an iodine value of 40 - 50 g I2 / 100g, an ash content of 12% - 14% at 950 °C, a melting point of 98 - 108 °C, and a zinc oxide content of 12% - 14%.

[0013] In a second aspect, an embodiment of the present invention provides a method for preparing the tread rubber of the all-steel drive tire described in the first aspect, including the following steps: (1) First-stage mixing: Charge 20 - 60 parts of natural rubber, 20 - 60 parts of smoked sheet rubber, 20 - 40 parts of rare earth cis-polybutadiene rubber, 5 - 35 parts of white carbon black, 10 - 30 parts of reinforcing carbon black, 1 - 3.5 parts of silane coupling agent, and 1 - 3 parts of physical plasticizer into a mixer for mixing. When the upper ram pressure is 4.0 - 5.9 MPa, the rotor speed is 25 - 45 r / min, and the temperature of the rubber compound is 100 - 120 °C, open the feed port again to add 2 - 5 parts of zinc oxide, 2 - 5 parts of stearic acid, and 0.5 - 3 parts of protective wax. Start constant-temperature rubber mixing: Keep the temperature constant at 120 - 145 °C for 50 - 90 seconds, and the discharge temperature is 145 - 152 °C. The overall rubber mixing time is 160 - 260 s to obtain the first-stage mixed rubber; (2)Two-stage mixing: Put the one-stage mixed rubber obtained in step (1), the remaining 10 - 30 parts of reinforcing carbon black, and 2 - 6 parts of antioxidant into a mixer for mixing. The pressure of the upper plug is 4.0 - 5.9 MPa, the rotor speed is 25 - 45 r / min. When the temperature of the rubber compound reaches 110 - 145 °C, start constant-temperature rubber mixing: keep the temperature constant at 120 - 145 °C for 20 - 60 seconds, the discharge temperature is 145 - 155 °C, and the overall rubber mixing time is 110 - 180 s to obtain the two-stage mixed rubber; (3)Three-stage mixing: Put the two-stage mixed rubber obtained in step (2), 0.5 - 2 parts of accelerator NS, 0.5 - 2 parts of sulfur powder, and 0.1 - 0.5 parts of anti-scorching agent CTP into a mixer for mixing. The rotor speed is 20 - 40 r / min, the pressure of the upper plug is 4.0 - 5.9 MPa, the discharge temperature is 100 - 110 °C, and the time is 110 - 140 s to obtain the finished tread rubber.

[0014] The beneficial effects brought by the technical solution provided by the embodiment of the present invention are as follows: (1)In the present invention, neodymium-based cis-butadiene rubber is introduced into the rubber compound, and the obtained rubber compound can meet the basic properties of long-distance tread rubber: hardness, tear resistance, wear resistance, etc. At the same time, it meets the requirements under European rain and snow weather conditions: low-temperature flexibility, wet skid resistance, ice skid resistance, environmental compliance, and possibly low rolling resistance. At the same time, the selection of materials also needs to meet European environmental protection and safety standards.

[0015] (2)The preparation method of the present invention has a simple process and is easy to realize large-scale industrial production. Specific embodiments

[0016] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention and are not used to limit the present invention.

[0017] Comparative example 1 A method for preparing a tread rubber for all-steel drive tires includes the following steps: (1)One-stage mixing: By weight, 50 parts of natural rubber, 50 parts of RSS3 smoked sheet rubber, 10 parts of 1165MP precipitated silica, 25 parts of N134 reinforcing carbon black, 1 part of liquid silane coupling agent Si 69 and 2 parts of physical plasticizer SL 5055 are put into a BB430 internal mixer for mixing. The upper plug pressure is 5.5 MPa, the rotor speed is 35 r / min. When the temperature of the rubber compound reaches 115 °C, 3.5 parts of zinc oxide, 2.5 parts of stearic acid and 1 part of protective wax SUNPRAX-672 are put into the feeding port again. Start constant-temperature rubber mixing: The constant temperature is 140 °C, the duration is 70 seconds, the discharge temperature is 145 °C, and the overall rubber mixing time is 226 s to obtain one-stage mixed rubber; (2)Two-stage mixing: Put the one-stage mixed rubber obtained in step (1) that has been parked for more than 8 hours, 25 parts of N134 reinforcing carbon black, 1 part of antioxidant RD and 1.5 parts of antioxidant 4020 into a BB430 internal mixer for mixing. The upper plug pressure is 5.0 MPa, the rotor speed is 35 r / min. When the temperature of the rubber compound reaches 138 °C, start constant-temperature rubber mixing: The constant temperature is 140 °C, the duration is 50 seconds, the discharge temperature is 145 °C, and the overall rubber mixing time is 170 s to obtain two-stage mixed rubber; (3)Three-stage mixing: Put the two-stage mixed rubber obtained in step (2) that has been parked for more than 4 hours, 1.2 parts of accelerator NS, 1.1 parts of sulfur powder and 0.35 part of scorch retarder CTP into an F270 internal mixer for mixing. The rotor speed is 24 r / min, the upper plug pressure is 5.9 MPa, the discharge temperature is 105 °C, and the time is 130 s to obtain the finished tread rubber.

[0018] Example 1 A preparation method of a tread rubber for all-steel drive tires, comprising the following steps: (1)One-stage mixing: By weight, 40 parts of natural rubber, 40 parts of RSS3 smoked sheet rubber, 20 parts of neodymium-based cis-1,4-polybutadiene rubber CB22, 10 parts of 1165MP precipitated silica, 25 parts of N134 reinforcing carbon black, 1 part of liquid silane coupling agent Si 69 and 2 parts of physical plasticizer SL 5055 are put into a BB430 internal mixer for mixing. The upper plug pressure is 5.5 MPa, the rotor speed is 35 r / min. When the temperature of the rubber compound reaches 115 °C, 3.5 parts of zinc oxide, 2.5 parts of stearic acid and 1 part of protective wax SUNPRAX-672 are put into the feeding port again. Start constant-temperature rubber mixing: The constant temperature is 140 °C, the duration is 70 seconds, the discharge temperature is 145 °C, and the overall rubber mixing time is 226 s to obtain one-stage mixed rubber; (2)Two-stage mixing: Put the one-stage mixed rubber obtained in step (1) that has been parked for more than 8 hours, 25 parts of N134 reinforcing carbon black, 1 part of antioxidant RD, and 1.5 parts of antioxidant 4020 into a BB430 internal mixer for mixing. The pressure of the upper plug is 5.0 MPa, the rotor speed is 35 r / min. When the temperature of the rubber compound reaches 138 °C, start constant-temperature rubber mixing: keep the temperature constant at 140 °C for 50 seconds, the discharge temperature is 145 °C, and the overall rubber mixing time is 170 s to obtain the two-stage mixed rubber; (3)Three-stage mixing: Put the two-stage mixed rubber obtained in step (2) that has been parked for more than 4 hours, 1.2 parts of accelerator NS, 1.1 parts of sulfur powder, and 0.35 parts of scorch retarder CTP into an F270 internal mixer for mixing. The rotor speed is 24 r / min, the pressure of the upper plug is 5.9 MPa, the discharge temperature is 105 °C, and the time is 130 s to obtain the finished tread rubber.

[0019] Example 2 A preparation method of a tread rubber for all-steel drive tires, comprising the following steps: (1)One-stage mixing: By weight, put 35 parts of natural rubber, 35 parts of RSS3 smoked sheet rubber, 30 parts of neodymium-based cis-butadiene rubber CB22, 10 parts of 1165MP silica, 25 parts of N134 reinforcing carbon black, 1 part of liquid silane coupling agent Si 69, and 2 parts of physical plasticizer SL 5055 into a BB430 internal mixer for mixing. The pressure of the upper plug is 5.5 MPa, the rotor speed is 35 r / min. When the temperature of the rubber compound reaches 115 °C, open the feed port again and put in 3.5 parts of zinc oxide, 2.5 parts of stearic acid, and 1 part of protective wax SUNPRAX-672 to start constant-temperature rubber mixing: keep the temperature constant at 140 °C for 70 seconds, the discharge temperature is 145 °C, and the overall rubber mixing time is 226 s to obtain the one-stage mixed rubber; (2)Two-stage mixing: Put the one-stage mixed rubber obtained in step (1) that has been parked for more than 8 hours, 25 parts of N134 reinforcing carbon black, 1 part of antioxidant RD, and 1.5 parts of antioxidant 4020 into a BB430 internal mixer for mixing. The pressure of the upper plug is 5.0 MPa, the rotor speed is 35 r / min. When the temperature of the rubber compound reaches 138 °C, start constant-temperature rubber mixing: keep the temperature constant at 140 °C for 50 seconds, the discharge temperature is 145 °C, and the overall rubber mixing time is 170 s to obtain the two-stage mixed rubber; (3)Three-stage mixing: Put the two-stage mixed rubber obtained in step (2) that has been parked for more than 4 hours, 1.2 parts of accelerator NS, 1.1 parts of sulfur powder, and 0.35 parts of scorch retarder CTP into an F270 internal mixer for mixing. The rotor speed is 24 r / min, the pressure of the upper plug is 5.9 MPa, the discharge temperature is 105 °C, and the time is 130 s to obtain the finished tread rubber.

[0020] Example 3 A preparation method of a steel-belted driving tire tread rubber, comprising the following steps: (1) First-stage mixing: By weight, 30 parts of natural rubber, 30 parts of RSS3 smoked sheet rubber, 40 parts of neodymium-based cis-1,4-polybutadiene rubber CB22, 10 parts of 1165MP precipitated silica, 25 parts of N134 reinforcing carbon black, 1 part of liquid silane coupling agent Si 69, and 2 parts of physical plasticizer SL5055 are put into a BB430 internal mixer for mixing. The upper ram pressure is 5.5 MPa, the rotor speed is 35 r / min. When the temperature of the rubber compound reaches 115 °C, 3.5 parts of zinc oxide, 2.5 parts of stearic acid, and 1 part of protective wax SUNPRAX-672 are put into the feed inlet again. Start constant-temperature rubber mixing: The constant temperature is 140 °C, the duration is 70 s, the discharge temperature is 145 °C, and the overall rubber mixing time is 226 s to obtain the first-stage mixed rubber; (2) Second-stage mixing: The first-stage mixed rubber obtained in step (1) that has been parked for more than 8 hours, 25 parts of N134 reinforcing carbon black, 1 part of antioxidant RD, and 1.5 parts of antioxidant 4020 are put into a BB430 internal mixer for mixing. The upper ram pressure is 5.0 MPa, the rotor speed is 35 r / min. When the temperature of the rubber compound reaches 138 °C, start constant-temperature rubber mixing: The constant temperature is 140 °C, the duration is 50 s, the discharge temperature is 145 °C, and the overall rubber mixing time is 170 s to obtain the second-stage mixed rubber; (3) Third-stage mixing: The second-stage mixed rubber obtained in step (2) that has been parked for more than 4 hours, 1.2 parts of accelerator NS, 1.1 parts of sulfur powder, and 0.35 part of scorch retarder CTP are put into an F270 internal mixer for mixing. The rotor speed is 24 r / min, the upper ram pressure is 5.9 MPa, the discharge temperature is 105 °C, and the time is 130 s to obtain the finished tire tread rubber.

[0021] The steel-belted driving wheel tire tread rubber obtained in Examples 1-3 of the present invention is vulcanized under the vulcanization conditions: 151 °C, 30 minutes. The physical properties of the vulcanized rubber are shown in Table 1.

[0022] Table 1 Physical properties of the finished tire tread rubber prepared in Comparative Example 1 and Examples 1-3 after vulcanization

[0023] From the physical property test data shown in Table 1, it can be seen that compared with Comparative Example 1, Examples 1, 2, and 3 have increased hardness, decreased 300% modulus, decreased tear strength, decreased Akron abrasion, decreased cut resistance volume ratio, decreased heat build-up under compression, decreased tanD (0°C), and decreased tanD (60°C). It can be thus known that in the tread compound of all-steel drive tires, adding a certain amount of neodymium-based cis-1,4-polybutadiene rubber can improve the Akron abrasion, cut resistance volume ratio, heat build-up, and wet grip of the final compound to a certain extent, while the modulus and tear resistance performance decrease. After comprehensive balance analysis of all the above test data and considering various aspects, the tread compounds prepared in Examples 1-3 can all meet the performance requirements. In particular, the tire tread compound obtained in Example 2 can meet the basic performance requirements of long-distance tread compounds, such as hardness, tear resistance, and abrasion resistance, and at the same time meet the requirements for use in European rainy and snowy weather conditions, including low-temperature flexibility, wet grip, ice grip, and possibly low rolling resistance. At the same time, the selection of materials also needs to meet European environmental protection and safety standards.

[0024] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the examples, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A tread rubber for all-steel drive tires, characterized in that, By weight parts, it includes the following components: 20 - 60 parts of natural rubber, 20 - 60 parts of smoked sheet rubber, 20 - 40 parts of rare earth cis-1,4-polybutadiene rubber, 5 - 35 parts of white carbon black, 20 - 60 parts of reinforcing carbon black, 2 - 5 parts of zinc oxide, 2 - 5 parts of stearic acid, 2 - 6 parts of antioxidant, 0.5 - 3 parts of protective wax, 1 - 3.5 parts of silane coupling agent, 1 - 3 parts of physical plasticizer, 0.5 - 2 parts of accelerator NS, 0.5 - 2 parts of sulfur powder, and 0.1 - 0.5 parts of scorch retarder CTP; Among them, the total of the natural rubber, smoked sheet rubber and rare earth cis-1,4-polybutadiene rubber is 100 parts.

2. The all-steel drive tire tread rubber according to claim 1, wherein The smoked sheet rubber is cis-1,4-polyisoprene.

3. The all-steel drive tire tread rubber according to claim 1, wherein The rare earth cis-1,4-polybutadiene rubber is neodymium-based polybutadiene rubber with a cis content higher than 96% and is non-oil-filled; The neodymium-based polybutadiene rubber is cis-1,4-polybutadiene rubber prepared by solution polymerization of butadiene under a neodymium-based catalyst system.

4. The all-steel drive tire tread rubber according to claim 1, characterized in that, The silica is HD175MP or 1165MP with a specific surface area of 160 - 180 m 2 / g; The silane coupling agent is liquid Si69 or Si75.

5. The all-steel drive tire tread rubber according to claim 1, characterized in that, The reinforcing carbon black includes at least one of N134 and BL101.

6. The all-steel drive tire tread rubber according to claim 1, wherein The antioxidant includes 1.5 - 3.5 parts of p-phenylenediamine antioxidant 4020 and 0.5 - 2.5 parts of ketoamine antioxidant RD.

7. The all-steel drive tire tread rubber according to claim 1, wherein The protective wax is bimodal microcrystalline wax or trimodal microcrystalline wax.

8. The all-steel drive tire tread rubber according to claim 1, wherein The physical plasticizer is a mixture of fatty acid zinc soap salts, with an iodine value of 40 - 50 g I2 / 100g, an ash content of 12% - 14% at 950°C, a melting point of 98 - 108°C, and a zinc oxide content of 12% - 14%.

9. The preparation method of the all-steel drive tire tread rubber according to any one of claims 1-8, characterized in that, It includes the following steps: (1) First-stage mixing: Put 20 - 60 parts of natural rubber, 20 - 60 parts of smoked sheet rubber, 20 - 40 parts of rare earth cis-1,4-polybutadiene rubber, 5 - 35 parts of white carbon black, 10 - 30 parts of reinforcing carbon black, 1 - 3.5 parts of silane coupling agent, and 1 - 3 parts of physical plasticizer into a mixer for mixing. The top plug pressure is 4.0 - 5.9 MPa, the rotor speed is 25 - 45 r / min. When the temperature of the rubber compound is 100 - 120°C, open the feed port again and put in 2 - 5 parts of zinc oxide, 2 - 5 parts of stearic acid, and 0.5 - 3 parts of protective wax. Start constant-temperature rubber mixing: Keep the temperature constant at 120 - 145°C for 50 - 90 seconds. The discharge temperature is 145 - 152°C, and the overall rubber mixing time is 160 - 260 s to obtain the first-stage mixed rubber; (2) Second-stage mixing: Put the first-stage mixed rubber obtained in step (1), the remaining 10 - 30 parts of reinforcing carbon black, and 2 - 6 parts of antioxidant into a mixer for mixing. The top plug pressure is 4.0 - 5.9 MPa, the rotor speed is 25 - 45 r / min. When the temperature of the rubber compound is 110 - 145°C, start constant-temperature rubber mixing: Keep the temperature constant at 120 - 145°C for 20 - 60 seconds. The discharge temperature is 145 - 155°C, and the overall rubber mixing time is 110 - 180 s to obtain the second-stage mixed rubber; (3)Three-stage mixing: Put the two-stage mixed rubber obtained in step (2), 0.5 - 2 parts of accelerator NS, 0.5 - 2 parts of sulfur powder, and 0.1 - 0.5 parts of anti-scorching agent CTP into a mixer for mixing. The rotor speed is 20 - 40 r / min, the pressure of the upper plug is 4.0 - 5.9 MPa, the discharge temperature is 100 - 110 °C, and the time is 110 - 140 s to obtain the finished tread rubber.

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