Four-season tire tread rubber material with high dynamic performance and preparation method thereof

Abstract

The present invention discloses a high dynamic performance four-season tire tread rubber material and a preparation method thereof, and relates to the technical field of tire materials, the high dynamic performance four-season tire tread rubber material comprises the following components: 100 parts of a rubber matrix, 15-35 parts of natural rubber, 10-30 parts of butadiene rubber BR9000, 50-75 parts of solution polymerized styrene butadiene rubber SSBR and 5-10 parts of chloroprene rubber CR; the composite material comprises the following components in parts by weight: 60-90 parts of reinforcing filler, irradiation modified white carbon black containing 100-250m < 2 > / g of BET and carbon black containing 80-130m < 2 > / g of BET, 4-6 parts of a coupling agent system and 6-12 parts of C5 / C9 petroleum resin, 2-3.5 parts of protective wax, wherein the protective wax comprises 30-35% of C26-C32 isoparaffin and microcrystalline wax; 2 to 4 parts of a sulfur system, which comprises 0.8 to 1.2 parts of pre-dispersed sulfur master batch and an accelerant TBzTD, and 1.2 to 2.5 parts of NS; and 1-3 parts of a functional auxiliary agent, wherein the functional auxiliary agent comprises a graphene / graphene oxide composite master batch, a scorch retarder CTP and bio-based naphthenic oil.

Description

Technical Field

[0001] The present invention relates to the technical field of tire materials, and particularly to a high-dynamic-performance all-season tire tread compound and a preparation method thereof. Background Art

[0002] All-season tires have both the dry grip and wet grip of summer tires and the low-temperature performance of winter tires. In recent years, the demand for all-season tires has been increasing, and their widespread use is in latitudes similar to those in North China of our country. The development focus of all-season tires is the tread formula design, which should meet the performance requirements of both summer tires and winter tires.

[0003] Generally, in order to meet the winter performance of the tread, special rubber compound formula designs are adopted, such as cis-1,4-polybutadiene rubber and natural rubber with excellent low-temperature performance, rubber processing oils with a low glass transition temperature Tg, etc. To meet the summer tread performance, materials such as emulsion-polymerized or solution-polymerized styrene-butadiene rubber and high-specific-surface-area silica are used. Now, to achieve the functions of both in one formula and meet the performance requirements of both summer and winter tires, a unique design of the tread formula is required.

[0004] In the tests of all-season tires, the common feedback is poor winter performance. The purpose of the present invention is to design and manufacture an all-season tire tread formula that can meet the test requirements and has practical application significance. The focus of the present invention is to improve the low-temperature performance of the compound and reduce the Tg (glass transition temperature) of the compound. Summary of the Invention

[0005] The present invention provides a high-dynamic-performance all-season tire tread compound and a preparation method thereof to solve the above problems existing in the prior art.

[0006] The present invention provides a high-dynamic-performance all-season tire tread compound, comprising:

[0007] 100.0 parts of a rubber matrix, which is composed of 15.0 - 35.0 parts of natural rubber, 10.0 - 30.0 parts of cis-1,4-polybutadiene rubber BR9000, 50.0 - 75.0 parts of solution-polymerized styrene-butadiene rubber SSBR, and 5.0 - 10.0 parts of chloroprene rubber CR;

[0008] 60.0 - 90.0 parts of a reinforcing filler, including irradiated modified silica with a BET of 100 - 250 m 2 / g and carbon black with a BET of 80 - 130 m 2 / g, and the mass ratio of the two is 1:1 - 1:1.2;

[0009] 4.0 - 6.0 parts of a coupling agent system, which is compounded from bis(triethoxysilylpropyl)tetrasulfide, bis(γ-triethoxysilylpropyl)disulfide, and silane coupling agent Si69 in a mass ratio of 3:1:0.5;

[0010] 6.0 - 12.0 parts of C5 / C9 petroleum resin, softening point 85 - 105°C, molecular weight distribution index PDI ≤ 2.3, aromatic content ≥ 45%;

[0011] 2.0 - 3.5 parts of protective wax, containing 30 - 35% of C26 - C32 isoparaffin and microcrystalline wax (penetration 15 - 200.1 mm);

[0012] 2.0 - 4.0 parts of sulfur system, including pre - dispersed sulfur masterbatch (EVA carrier, sulfur content 70 - 80%) and accelerator TBzTD 0.8 - 1.2 parts, NS 1.2 - 2.5 parts;

[0013] 1.0 - 3.0 parts of functional additives, including graphene / graphene oxide composite masterbatch, anti - scorching agent CTP and bio - based naphthenic oil (Tg ≤ - 55°C).

[0014] Optionally, the irradiated modified silica is prepared by grafting styrene - butadiene copolymer through γ - ray irradiation, with a grafting rate of 8 - 12%. Its preparation method includes:

[0015] (a) Immerse the silica in styrene - butadiene copolymer emulsion (solid content 20 - 30%) and ultrasonically disperse for 20 - 30 min;

[0016] (b) Carry out γ - ray irradiation treatment with an irradiation dose of 15 - 25 kGy, and vacuum dry after irradiation until the water content ≤ 0.5%.

[0017] Optionally, the graphene / graphene oxide composite masterbatch is prepared by ball - milling graphene, graphene oxide and natural rubber in a mass ratio of 1:0.5:3, with a particle size ≤ 200 nm, and the ball - milling time is 4 - 6 hours, and the ball - to - material ratio is 10:1.

[0018] Optionally, the mass ratio of the bio - based naphthenic oil to the low - PAHs oil is 1:2 - 1:4, and the kinematic viscosity (40°C) of the bio - based naphthenic oil is 20 - 30 mm 2 / s.

[0019] Optionally, the melting point of the microcrystalline wax is 75 - 85°C, and the mass ratio of it to the C26 - C32 isoparaffin in the protective wax is 1:3 - 1:5.

[0020] On the other hand, the present invention also provides a preparation method of a tread rubber compound for all - season tires. The method includes the following steps:

[0021] (1) First-stage masterbatch mixing: Add the rubber matrix, 2 / 3 of the reinforcing filler, and the coupling agent system to the internal mixer, mix at 50 - 70 r / min for 30 - 40 seconds, inject the ultrasonic vibrator (frequency 25 - 45 kHz, power density 2.0 - 2.5 W / cm 3 ) and disperse for 15 - 25 seconds, and simultaneously apply a pulsed current (voltage 3.1 - 3.3 V, current density 160 - 168 A / mm 2 );

[0022] (2) Second-stage masterbatch mixing: Add the remaining reinforcing filler, C5 / C9 petroleum resin, and protective wax, the internal mixer rotates at 40 - 60 r / min, and discharge the rubber at a controlled temperature of 155 - 160 °C;

[0023] (3) Final mixing: Add the sulfur system and accelerator in two stages. First, add 70% of the sulfur masterbatch and mix for 20 seconds (temperature ≤ 110 °C), then add the remaining 30% of the sulfur masterbatch and mix to the end (temperature ≤ 90 °C).

[0024] Optionally, the application time of the pulsed current is 1 / 2 of the ultrasonic action time, and the current direction is perpendicular to the ultrasonic vibration direction.

[0025] Optionally, in the final mixing stage, accelerator NS is added in two times: 60% of the total amount is first added and mixed with 70% of the sulfur masterbatch, and the remaining 40% is added synchronously with 30% of the sulfur masterbatch.

[0026] Optionally, the power density of the ultrasonic wave in the first-stage masterbatch mixing is 2.2 W / cm 3 , and the ratio of the action time to the total mixing time is 1:4

[0027] Optionally, the addition method of the reinforcing filler is: 80% of the total amount of silica and 50% of the total amount of carbon black are added in the first-stage masterbatch mixing, and the remaining silica and carbon black are added in the second-stage masterbatch mixing.

[0028] The present invention has the following beneficial effects compared with the prior art:

[0029] After using natural rubber in the all-season tread rubber, the low-temperature performance of the tread can be significantly improved. Typical data shows that the Tg value drops from -19.4°C of the comparative value to about -45°C. In addition, the wet grip performance is tested by a DMA testing machine for tanδ at 0°C. The larger the reported value, the higher the wet grip performance. The fuel economy performance is tested by a DMA testing machine for tanδ at 60°C. The smaller the reported value, the better the fuel-saving performance. CR and bio-based naphthenic oil (Tg ≤ -55°C) act synergistically, the hardness change rate at -40°C ≤ 5%, and the graphene masterbatch (thermal conductivity ≥ 200 W / m·K) reduces the tread temperature by 10 - 15°C, and the wear amount is reduced by 30%. The ultrasonic-pulsed current synergistic dispersion destroys the filler agglomeration through the ultrasonic cavitation effect (power density 2.0 - 2.5 W / cm 3 ) and the pulsed current (3.1 - 3.3 V) aligns the fillers through the electromagnetic field, synergistically improving the dispersion efficiency by more than 30%. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] 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 following drawings 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.

[0031] Figure 1 It is a flowchart of the preparation method of a tread compound for an all-season tire of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The following will clearly and completely describe the technical solutions of the present invention in conjunction 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 fall within the scope of protection of the present invention.

[0033] Unless otherwise specified, the raw materials used in the present invention are all conventional products purchased from the market.

[0034] Example 1

[0035] As Figure 1 shown, the embodiment of the present invention provides a tread compound for an all-season tire with high dynamic performance, including:

[0036] Rubber matrix: 25 parts of NR, 20 parts of BR9000, 60 parts of SSBR (tin-coupled type, Tg -45°C), 8 parts of CR;

[0037] Reinforcing filler: 45 parts of irradiated modified silica (grafting rate 10%) and 40 parts of carbon black N330;

[0038] Coupling agent: 3.0 parts of TESPT, 1.0 part of TESPD, and 0.5 part of Si 69;

[0039] C5 / C9 petroleum resin: C9 accounts for 65%, PDI is 2.1, softening point is 95°C, 10 parts;

[0040] Protective wax: 32% of C28 isoparaffin + 1.2 parts of microcrystalline wax (penetration 180.1mm), total amount 3.0 parts;

[0041] Sulfur system: 3.0 parts of pre-dispersed sulfur masterbatch (EVA carrier, sulfur content 75%), 1.0 part of TBzTD, and 2.0 parts of NS;

[0042] Functional additives: 1.0 part of graphene composite masterbatch, 0.3 part of scorch retarder CTP, and 1.5 parts of bio-based naphthenic oil (Tg -58°C).

[0043] A method for preparing a tread compound for all-season tires includes the following steps:

[0044] (1) First-stage masterbatch mixing: Add the rubber matrix, 2 / 3 of the reinforcing filler, and the coupling agent system to the internal mixer, mix at 50 - 70 r / min for 30 - 40 seconds, add the raw rubber, 2 / 3 of the carbon black, silica, and sulfur-containing organosilicon compound, press the upper ram and mix for 20 - 40 seconds; raise the upper ram, add the rubber processing oil, reduce the internal mixer speed to 35 - 55 r / min, press the upper ram, mix for 15 - 25 seconds, inject the ultrasonic oscillator (frequency 25 - 45 kHz, power density 2.0 - 2.5 W / cm 3 ) and disperse for 15 - 25 seconds, simultaneously apply a pulsed current (voltage 3.1 - 3.3 V, current density 160 - 168 A / mm 2 ), the application time of the pulsed current is 1 / 2 of the ultrasonic action time, and the current direction is perpendicular to the ultrasonic vibration direction, raise the upper ram to clean, reduce the internal mixer speed to 25 - 35 r / min, raise the upper ram, keep the temperature constant at 145°C for 30 - 40 seconds; press the upper ram until the temperature reaches 150°C; open the discharge door to discharge the rubber, extrude with a twin-screw and cool and arrange the sheets;

[0045] (2) Secondary masterbatch mixing: Add the remaining reinforcing fillers, C5 / C9 petroleum resin, and protective wax. Adjust the speed of the internal mixer to 35 - 55 r / min. Add the primary masterbatch, 1 / 3 of the carbon black, activators, antioxidant RD, antioxidant 4020, and protective wax. Press the upper ram and mix for 25 - 35 seconds, raise the upper ram and clean for 5 seconds, press the upper ram and mix for 25 - 35 seconds, raise the upper ram and hold for 5 seconds, press the upper ram and mix. When the temperature reaches 155°C, open the discharge door to discharge the rubber. Use a twin-screw extruder to cut into sheets, and cool and stack the sheets;

[0046] (3) Final mixing: Add the sulfur system and accelerators in two stages. First, add 70% sulfur masterbatch and mix for 20 seconds (temperature ≤ 110°C), then add the remaining 30% sulfur masterbatch and mix to the end (temperature ≤ 90°C). Accelerator NS is added in two times: First, add 60% of the total amount and mix with 70% sulfur masterbatch, and add the remaining 40% synchronously with 30% sulfur masterbatch. The mixing is carried out in a Banbury internal mixer with a speed of 15 - 40 revolutions per minute. Add the secondary masterbatch, vulcanizing agent, accelerator, and scorch retarder. Press the upper ram and mix for 25 - 35 seconds, raise the upper ram and clean for 5 seconds, press the upper ram and mix for 25 - 35 seconds, raise the upper ram, press the upper ram and mix for 25 - 35 seconds, raise the upper ram, press the upper ram and mix for 30 seconds, raise the upper ram, open the discharge door to discharge the rubber, and control the discharge temperature at 100 - 115°C; Use a two-roll mill to cut into sheets, and cool and stack the sheets.

[0047] It should be noted that the addition method of the reinforcing filler is as follows: 80% of the total amount of silica and 50% of the total amount of carbon black are added in the primary masterbatch mixing, and the remaining silica and carbon black are added in the secondary masterbatch mixing. The preparation process of Comparative Example 1 is the same as that of Examples 1 - 3.

[0048] Table 1 - Formulations of Examples 1 - 3 and Comparative Example 1

[0049]

[0050]

[0051] Table 2 - Physical Properties of the Compounds of Examples 1 - 3 and Comparative Example 1

[0052]

[0053]

[0054] As can be seen from Table 2, after using natural rubber in the all-season tread rubber, the low-temperature performance of the tread can be significantly improved. Typical data shows that the Tg value drops from -19.4 °C of the comparison value to about -45 °C. In addition, 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. The fuel economy performance is tested by a DMA testing machine for tanδ at 60 °C, and the smaller the reported value, the better the fuel-saving performance. The reinforcing agent of the present invention uses a mixture of fine-particle carbon black and silica to ensure the grip performance and wear resistance.

[0055] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high dynamic performance all-season tire tread rubber material, characterized in that: The following components are included by weight: 100.0 parts of rubber matrix, composed of 15.0-35.0 parts of natural rubber, 10.0-30.0 parts of butadiene rubber BR9000, 50.0-75.0 parts of solution styrene butadiene rubber SSBR and 5.0-10.0 parts of chloroprene rubber CR; Reinforcing filler 60.0~90.0 parts, including BET 100~250m 2 / g irradiation modified silica and BET 80~130m 2 / g of carbon black, the mass ratio of the two is 1:1 to 1:1.2; 4.0-6.0 parts of coupling agent system, which is prepared by mixing 3,3'-bis(triethoxysilylpropyl)tetrasulfide, bis(γ-triethoxysilylpropyl)disulfide and silane coupling agent Si 69 in a mass ratio of 3:1:0.5; C5 / C9 petroleum resin 6.0-12.0 parts, softening point 85-105°C, molecular weight distribution index PDI ≤ 2.3, aromatic content ≥ 45%; 2.0-3.5 parts of protective wax, including 30-35% C26-C32 isoparaffin and microcrystalline wax; Sulfur system 2.0-4.0 parts, including pre-dispersed sulfur masterbatch and accelerator TBzTD 0.8-1.2 parts, NS 1.2-2.5 parts; The functional additives are 1.0 to 3.0 parts, including graphene / graphene oxide composite masterbatch, anti-scorch agent CTP and bio-based cyclohexane oil.

2. The rubber material according to claim 1, characterized in that: The irradiated modified white carbon black is prepared by grafting styrene-butadiene copolymer by γ-ray irradiation, with a grafting rate of 8-12%. The preparation method thereof comprises: (a) impregnating white carbon black into a styrene-butadiene copolymer emulsion (solid content 20-30%) and ultrasonically dispersing the emulsion for 20-30 minutes; (b) γ-ray irradiation treatment with an irradiation dose of 15-25 kGy, followed by vacuum drying to a moisture content of ≤0.5%.

3. The rubber material according to claim 1, characterized in that: The graphene / graphene oxide composite masterbatch is prepared by ball milling graphene, graphene oxide and natural rubber at a mass ratio of 1:0.5:3, with a particle size of ≤200nm, and the ball milling time is 4-6 hours, with a ball-to-material ratio of 10:

1.

4. The rubber material according to claim 1, characterized in that: The mass ratio of the bio-based naphthenic oil to the low PAHs oil is 1:2 to 1:4, and the kinematic viscosity (40°C) of the bio-based naphthenic oil is 20-30 mm 2 / s.

5. The rubber material according to claim 1, characterized in that: The melting point of the microcrystalline wax is 75-85° C., and the mass ratio of the microcrystalline wax to the C26-C32 isoparaffin in the protective wax is 1:3 to 1:

5.

6. A method for preparing the tread rubber material for all-season tires according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) Master batching: Add the rubber matrix, 2 / 3 reinforcing filler, and coupling agent system into an internal mixer, mix at 50-70 r / min for 30-40 seconds, and inject an ultrasonic vibrator (frequency 25-45 kHz, power density 2.0-2.5 W / cm 3 ) for 15-25 seconds, and simultaneously apply pulse current (voltage 3.1-3.3V, current density 160-168A / mm 2 ); (2) Second stage master batching: add the remaining reinforcing filler, C5 / C9 petroleum resin and protective wax, the internal mixer speed is 40-60r / min, and the temperature is controlled at 155-160℃ for rubber removal; (3) Final refining: Add the sulfur system and accelerator in two stages. First, add 70% of the sulfur masterbatch and mix for 20 seconds (temperature ≤ 110°C), and then add the remaining 30% of the sulfur masterbatch and mix to the end point (temperature ≤ 90°C).

7. The preparation method according to claim 6, characterized in that: The application time of the pulse current is 1 / 2 of the ultrasonic action time, and the current direction is perpendicular to the ultrasonic vibration direction.

8. The preparation method according to claim 6, characterized in that: In the final refining stage, the accelerator NS is added twice: 60% of the total amount is first added and mixed with 70% of the sulfur masterbatch, and the remaining 40% is added simultaneously with 30% of the sulfur masterbatch.

9. The preparation method according to claim 6, characterized in that: The power density of the ultrasonic wave in the master batch is 2.2 W / cm 3 The ratio of action time to total mixing time is 1:

4.

10. The preparation method according to claim 6, characterized in that: The reinforcing filler is added in the following manner: 80% of the total amount of white carbon black and 50% of the total amount of carbon black are added in the first stage of master batching, and the remaining white carbon black and carbon black are added in the second stage of master batching.

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