Low rolling resistance low temperature rise tire tread rubber material and method of making same

Abstract

The application relates to the field of tires, in particular to a low-rolling-resistance and low-temperature-rise tire tread rubber material and a preparation method thereof, which comprises the following components in parts by weight: 1,4-trans polyisoprene rubber 0-50 parts, natural rubber 0-100 parts, silica 10-60 parts, carbon black 0-100 parts, white carbon black 0-80 parts, silane coupling agent 0-20 parts, stearic acid 1-5 parts, zinc oxide 1-5 parts, antioxidant 1-3 parts, accelerator 1-4 parts, naphthenic oil 1-5 parts and sulfur 1-4 parts. Compared with the prior art, the tire tread rubber material uses 1,4-trans polyisoprene rubber and natural rubber as the base rubber, silica, carbon black and white carbon black as the composite filler, and cooperates with other auxiliary materials, so that the rolling resistance and dynamic temperature rise of the rubber material are effectively reduced, and the rubber material has good wear resistance and physical and mechanical properties.

Description

Technical Field

[0001] This invention belongs to the field of new tire materials technology, and relates to a low rolling resistance and low temperature rise tire tread compound material and its preparation method. The invented tread compound material can effectively reduce the rolling resistance and dynamic temperature rise of the tire during driving, and is energy-saving and environmentally friendly. Background Technology

[0002] Tires are a crucial component of modern automobiles, playing a vital role in load-bearing, traction, and braking. Tires are a typical rubber composite system. Due to the high strength, excellent physical properties, and adhesive properties of natural rubber, current automotive tire carcass rubber materials typically use all-natural rubber or natural rubber with a small amount of styrene-butadiene rubber (SBR), with carbon black as the filler. During driving, tires continuously deform, and under alternating loads, heat is generated due to hysteresis losses, causing the internal temperature to rise. This reduces the tire's airtightness and the adhesion strength to the carcass material. Simultaneously, increased deformation increases rolling resistance, leading to fatigue damage to the natural rubber system and potentially causing safety accidents. Therefore, reducing tire rolling resistance and dynamic heat rise through material selection and formulation adjustments in rubber composite systems is of significant practical importance.

[0003] Patent application CN202110835949.3 discloses a low-heat tire tread formulation, comprising natural rubber, wollastonite, carbon black, silica, coupling agent, stearic acid, zinc oxide, antioxidant, accelerator, and sulfur. Because wollastonite can reduce the temperature rise of the surface and core of the vulcanized product under alternating loads, it lowers the Mooney viscosity of the compound while ensuring good performance. Therefore, the vulcanized composite material prepared with wollastonite generates less heat under alternating loads, resulting in a smaller temperature rise of the surface and core. This leads to better mechanical properties in the vulcanized product, ensuring the quality of the final product. Furthermore, it reduces environmental problems during production, lowers the production cost of rubber products, and improves economic and social benefits. However, this formula only uses natural rubber as the base rubber and does not improve the rubber molecular chain structure to reduce rolling resistance and dynamic heat generation. In addition, natural rubber is expensive and domestic resources are limited. Wollastonite, as a natural inorganic filler, can give rubber excellent physicochemical properties due to its needle-like or fibrous structure, but its dispersion in the rubber matrix is ​​difficult to control, which is an urgent problem to be solved in rubber processing. Summary of the Invention

[0004] The purpose of this invention is to overcome the defects of the prior art by providing a low rolling resistance and low temperature rise tire tread compound material and its preparation method, which can effectively reduce tire rolling resistance and effectively reduce the temperature rise of the surface and center temperature of the vulcanized rubber.

[0005] The objective of this invention can be achieved through the following technical solution: a low rolling resistance and low temperature rise tire tread material, characterized in that it comprises the following components in parts by weight: 0-50 parts of 1,4-trans polyisoprene rubber, 0-100 parts of natural rubber, 10-60 parts of silica, 0-100 parts of carbon black, 0-80 parts of silica, 0-20 parts of silane coupling agent, 1-5 parts of stearic acid, 1-5 parts of zinc oxide, 1-3 parts of antioxidant, 1-4 parts of accelerator, 1-5 parts of naphthenic oil, and 1-4 parts of sulfur.

[0006] Preferably, the material comprises the following components in parts by weight: 20-40 parts of 1,4-trans-polyisoprene rubber, 60-80 parts of natural rubber, 10-30 parts of silica, 10-30 parts of carbon black, 5-20 parts of silica, 1-10 parts of silane coupling agent, 1-3 parts of stearic acid, 2-4 parts of zinc oxide, 1-3 parts of antioxidant, 1-3 parts of accelerator, 1-5 parts of naphthenic oil, and 1-4 parts of sulfur.

[0007] More preferably, the material comprises the following components in parts by weight: 20-40 parts of 1,4-trans-polyisoprene rubber, 60-80 parts of natural rubber, 10-30 parts of silica, 10-30 parts of carbon black, 10 parts of silica, 5 parts of silane coupling agent, 2 parts of stearic acid, 3 parts of zinc oxide, 2 parts of antioxidant, 1.6 parts of accelerator, 3 parts of naphthenic oil, and 3 parts of sulfur.

[0008] Preferably, the 1,4-trans-polyisoprene rubber has a trans content of 99%, a number-average molecular weight of 100,000 to 500,000, and a molecular weight distribution index (PI) of 1.5 to 3. 1,4-trans-polyisoprene rubber, also known as synthetic eucommia rubber, is obtained by the directional polymerization of isoprene. It is an isomer of natural rubber and, similar to natural eucommia rubber, its molecular chain structure is more regular and ordered than that of natural rubber, making it easier to aggregate and form crystalline regions. It crystallizes rapidly at temperatures below 60°C, resulting in significantly different properties compared to natural rubber. By blending the two in a certain proportion and rationally controlling the crystallization of the trans-polyisoprene rubber, the tear strength, aging resistance, abrasion resistance, and dynamic heat rise of the blended rubber can be improved, showing broad application prospects.

[0009] Preferably, the natural rubber includes standard rubber, smoked sheet rubber, and air-dried rubber.

[0010] Preferably, the silica structure comprises microparticles, flakes, or stacked granules, with the main components including 75%–91% silica, 3%–14% alumina, and small amounts of iron (0.6%–2.1%), magnesium (0.4%–1.4%), etc. The median particle size is 0.5–5 μm. Its structure is formed by the natural combination of microparticle silica (silicic acid) and flake kaolinite, creating an aggregate with a unique stacked granular structure dominated by silica and containing a small amount of clay minerals. After simple processing, nano-sized powder can be obtained. As a novel filler, silica possesses high silica content, fine particle size, a unique stacked granular structure, and stable physicochemical properties. When mixed with rubber, it exhibits advantages such as good dispersibility, rapid powder absorption, non-sticking to rollers, low pollution, and low cost. The combined use of silica powder with silica or carbon black has a synergistic effect on reinforcing the performance of rubber materials.

[0011] Preferably, the stearic acid is octadecanoic acid;

[0012] The antioxidant is one or a combination of antioxidant 4020, antioxidant 4010, antioxidant 4010NA, and antioxidant RD;

[0013] The accelerator is one or a combination of several of the following: accelerator DPG, accelerator CZ, accelerator TMTD, and accelerator DM.

[0014] Preferably, the silica is nano-silica with a DBP absorption of 165–200 ml / 100 g and a CTAB specific surface area of ​​165–200 m² / g. 2 / g.

[0015] Preferably, the carbon black is one or a combination of N330, N550, and N660.

[0016] With the global resource crisis and increasing environmental awareness, green tires are the future development direction of the automotive tire industry, driving the increasing application of silica in tire tread compounds. Silica is a general term for hydrated silica, existing as an amorphous or flocculent powder with numerous hydroxyl groups on its surface, making it prone to water absorption and agglomeration. Compared to carbon black, silica can effectively reduce the rolling resistance of vulcanized rubber and reduce hysteresis loss; however, due to the large number of silanol groups on its surface, silica is highly polar and has poor compatibility with most hydrocarbon rubbers. Furthermore, its high surface energy leads to severe agglomeration between silica particles, making it difficult to disperse in rubber. Therefore, silane coupling agents are used to modify the surface of silica to improve its dispersibility and interfacial interaction with the rubber matrix; in addition, using it in combination with other fillers is also a way to enhance dispersibility.

[0017] Preferably, the silane coupling agent is one or a combination of several of KH550, KH560, and Si-69.

[0018] This invention also provides a method for preparing a low rolling resistance, low temperature rise tire tread compound material, comprising the following steps:

[0019] S1, Mixing

[0020] S11) Plasticize natural rubber on an open mill with a roller temperature of 25-35℃ and a roller gap of 0.3-1mm, and make thin triangular wraps 10-15 times.

[0021] S12) Plasticize 1,4-trans-polyisoprene rubber on an open mill with a roller temperature of 50℃~60℃ and a roller gap of 0.3~1.0mm, and make triangular wraps 10~15 times.

[0022] S13) Add the plasticized 1,4-trans-polyisoprene rubber to the natural rubber wrapped on the roller at a roller temperature of 45-60℃ and mix evenly.

[0023] S14) Add zinc oxide, stearic acid, accelerator, and antioxidant in sequence. After each addition of an auxiliary material, tap the rubber once on each side.

[0024] S15) Add silica and fumed silica in small batches. After each addition, cut the rubber on both sides once. After mixing evenly, add silane coupling agent in small batches and mix for 3-5 minutes.

[0025] S16) Add carbon black in batches and small amounts. After each addition, cut the rubber on both sides once. After the carbon black is completely mixed in, add naphthenic oil and sulfur. After mixing evenly, adjust the roller gap to 0.3-1.0 mm and make a thin triangular wrap 10-15 times. Then adjust the roller gap to 2-3 mm and determine the calendering direction to produce the sheet.

[0026] S17) The compound obtained in step S16) is left to stand at 25℃~30℃ for 12~18 hours;

[0027] S2, sulfurization

[0028] The compound obtained in step S17) is vulcanized at a temperature of 140-150℃ and a pressure of 30-40 MPa. The vulcanization time is the positive vulcanization time measured by a vulcanizer at the corresponding temperature. After vulcanization, the sample is left at room temperature for 10-20 hours to obtain the product.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. This invention, by selecting a reasonable rubber compound ratio and filler type, uses 1,4-trans-polyisoprene rubber and natural rubber as the base rubber, and silica, carbon black, and precipitated silica as the composite filler system. Combining the advantages and properties of each material, and by rationally controlling the production process, a tire tread compound material with low rolling resistance and low temperature rise is prepared. This material can effectively reduce tire energy consumption and has good economic and social prospects. In addition, silica is abundant and inexpensive, which can further reduce production costs and improve economic and social benefits.

[0031] 2. The tire tread compound of this invention uses 1,4-trans-polyisoprene rubber and natural rubber as the base rubber, and silica, carbon black, and precipitated silica as composite fillers, along with other auxiliary materials, to effectively reduce the rolling resistance and dynamic temperature rise of the compound. Specifically, the crystalline structure of trans-polyisoprene rubber reduces tire deformation and weakens intermolecular friction loss, thereby effectively reducing tire rolling resistance. Silica reduces the heat generated by the vulcanized rubber under alternating loads, thus effectively reducing the temperature rise of the vulcanized rubber surface and center. The addition of appropriate amounts of precipitated silica and silane coupling agents allows the silane coupling agents to react with or physically adsorb onto the surface of precipitated silica, resulting in a lower Mooney viscosity in the compound, promoting filler dispersion, improving compound flowability, and effectively reducing rolling resistance. The synergistic effect of the components gives the tread compound material prepared by this invention a low dynamic temperature rise, while also possessing good wear resistance and physical and mechanical properties.

[0032] 3. The tire tread rubber preparation process of this invention firstly involves uniformly plasticizing 1,4-trans-polyisoprene rubber and natural rubber by adjusting different roller temperatures, and then fully mixing them at an appropriate temperature to produce a uniformly mixed masterbatch. This allows the trans-polyisoprene rubber crystals to be uniformly dispersed in the rubber matrix, forming an island structure. Then, by calculating parameters such as the pre-dispersion rate, migration rate, and rubber vulcanization crosslinking rate of the additives, the feeding sequence is rationally controlled to promote the effective and uniform dispersion of fillers in the colloid, enabling the components in the rubber composite material to have a synergistic effect, effectively reducing the rolling resistance and dynamic temperature rise of the rubber compound. Detailed Implementation

[0033] The embodiments of the present invention are described in detail below. These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments.

[0034] Example 1

[0035] The low rolling resistance and low temperature rise tire tread compound material involved in this embodiment includes the following components by weight: 80 parts natural rubber, 20 parts 1,4-trans polyisoprene rubber, 10 parts silica, 10 parts silica, 30 parts carbon black (N330), 5 parts silane coupling agent (Si-69), 2 parts stearic acid, 3 parts zinc oxide, 1 part antioxidant (4010NA), 1 part antioxidant (RD), 1.6 parts accelerator (CZ), 3 parts naphthenic oil, and 3 parts sulfur.

[0036] The specific preparation process of the low rolling resistance and low temperature rise tire tread compound material involved in this embodiment is as follows:

[0037] I. Mixing

[0038] 1) Plasticize the natural rubber on a two-roll mill with a roller temperature of 30°C and a roller gap of 0.5 mm. Make 10 thin triangular wraps.

[0039] 2) Plasticize 1,4-trans-polyisoprene rubber on an open mill with a roller temperature of 55°C and a roller gap of 0.5 mm, and perform 10 thin triangular wraps.

[0040] 3) Add the plasticized 1,4-trans polyisoprene rubber to the natural rubber wrapped on the roller at a roller temperature of 50°C and mix evenly.

[0041] 4) Add zinc oxide, stearic acid, accelerator, and antioxidant in sequence. After each addition of an auxiliary material, tap the rubber once on each side.

[0042] 5) Add silica and fumed silica in small batches (in this example, add in three batches, each batch being 1 / 3 of the total amount, and add within 3 minutes). After each addition, cut the rubber on both sides once. After mixing evenly, add silane coupling agent in small batches and mix for 5 minutes.

[0043] 6) Add carbon black in batches and small amounts (in this embodiment, it is added in three batches, each time adding 1 / 3 of the total amount, and the addition is completed within 3 minutes). After each addition, cut the rubber on both sides once. After the carbon black is completely mixed evenly, add naphthenic oil and sulfur. After mixing evenly, adjust the roller gap to 0.5mm and make a thin triangular wrap 10 times. Then adjust the roller gap to 2mm and determine the calendering direction to produce the sheet.

[0044] 7) Let the rubber compound obtained in step 6 stand at 28°C for 16 hours.

[0045] II. Sulfidation

[0046] 8) The vulcanization characteristic curve of the rubber compound was measured by a rotorless vulcanizer. The vulcanization temperature was set to 143℃, the vulcanization pressure to 35MPa, and the vulcanization time to Tc90+3min.

[0047] The performance test of the low rolling resistance and low temperature rise tire tread rubber material obtained in this embodiment was conducted by replacing all the 1,4-trans-polyisoprene rubber in the formulation of Example 1 with natural rubber as the formulation of Comparative Example 1: 100 parts natural rubber, 10 parts silica, 10 parts silica, 30 parts carbon black (N330), 5 parts silane coupling agent (Si-69), 2 parts stearic acid, 3 parts zinc oxide, 1 part antioxidant (4010NA), 1 part antioxidant (RD), 1.6 parts accelerator (CZ), 3 parts naphthenic oil, and 3 parts sulfur. The silica in the formulation of Example 1 was completely replaced with fumed silica to form the formulation of Comparative Example 2: 80 parts natural rubber, 20 parts 1,4-trans polyisoprene rubber, 20 parts fumed silica, 30 parts carbon black (N330), 5 parts silane coupling agent (Si-69), 2 parts stearic acid, 3 parts zinc oxide, 1 part antioxidant (4010NA), 1 part antioxidant (RD), 1.6 parts accelerator (CZ), 3 parts naphthenic oil, and 3 parts sulfur.

[0048] Following the above process, Example 1, Comparative Example 1, and Comparative Example 2 were prepared into rubber samples for performance testing, as shown in the table below:

[0049] Test Project Comparative Example 1 Comparative Example 2 Example 1 Mooney viscosity / MU 35.13 42.25 38.35 100% constant tensile stress / MPa 2.14 2.98 3.16 300% constant tensile stress / MPa 11.02 11.39 11.52 Tensile strength / MPa 20.6 19.8 22.1 Elongation at break / % 601 487 593 ΔG' / KPa 133.53 196.75 136.27 tanδ@60℃ 0.09 0.09 0.08 Surface temperature rise / °C 21.3 24.1 14.2 Core temperature rise / ℃ 33.6 45.6 26.1 <![CDATA[Wear volume / cm 3 / 1.61 km]]> 0.24 0.14 0.16

[0050] The specific testing methods for the above-mentioned test items are as follows:

[0051] Mooney viscosity: Tested according to national standard GB / T 1232.1-2016 "Determination of Mooney viscosity of unvulcanized rubber";

[0052] 100% constant elongation stress, 300% constant elongation stress, tensile strength, and elongation at break: all were tested in accordance with the national standard GB528-82 "Determination of tensile properties of vulcanized rubber";

[0053] ΔG': The difference between the shear modulus of vulcanizate at 0.28% low strain and 40% high strain was measured using a rubber processing analyzer (RPA).

[0054] tanδ@60℃: The loss factor tanδ at 60℃ was measured using a Dynamic Mechanical Properties Analyzer (DMA) with temperature scanning.

[0055] Surface temperature rise: The temperature difference on the surface of the colloid is measured using a thermocouple temperature probe;

[0056] Center temperature rise: Insert the thermocouple temperature probe into the center of the colloid to measure the temperature difference at the center of the colloid;

[0057] Akron abrasion performance test: The test was conducted in accordance with GB / T1689-1998 "Determination of abrasion resistance of vulcanized rubber";

[0058] Where: ΔG‘ It can characterize the dispersion of filler particles in the rubber compound, ΔG ‘ The smaller the value, the better the filler dispersion in the rubber compound; the lower the tanδ@60℃, the smaller the rolling resistance; surface temperature rise and center temperature rise refer to the temperature rise of the sample's surface and internal center when an alternating load is applied to the test sample. As can be seen from the table: because the molecular chains of 1,4-trans-polyisoprene rubber are more regular than those of natural rubber and are more prone to crystallization, the addition of some 1,4-trans-polyisoprene rubber resulted in a slight increase in Mooney viscosity, 100% tensile stress, 300% tensile stress, and tensile strength in Example 1 compared to Comparative Example 1, while the elongation at break decreased slightly. Compared to Comparative Example 2, Example 1 shows that silica can reduce Mooney viscosity, which is beneficial for rubber compound processing; furthermore, after adding silica, the ΔG in Example 1... ‘ The value is significantly lower than ΔG in Comparative Example 2. ‘ This indicates better filler dispersion. The tanδ@60℃ value in Example 1 is lower than that in Comparative Examples 1 and 2, indicating that the rubber compound in Example 1 has lower rolling resistance when used in the tire tread. The microcrystalline regions formed by silica and 1,4-trans-polyisoprene rubber can reduce tire deformation and decrease intermolecular friction loss, thereby effectively reducing tire rolling resistance. Furthermore, compared to Comparative Example 1, the addition of 1,4-trans-polyisoprene rubber in Comparative Example 2 and Example 1 significantly reduces rubber compound wear. The surface and center temperature rise in Example 1 are significantly lower than those in Comparative Examples 1 and 2, showing a clear effect in temperature reduction. This indicates that proper control of the crystallinity of 1,4-trans-polyisoprene rubber and the proportion of silica can result in lower rolling resistance and lower heat generation in the tire tread under alternating loads, which is beneficial for ensuring tire performance and extending service life.

[0059] Example 2

[0060] The low rolling resistance and low temperature rise tire tread compound material involved in this embodiment includes the following components by weight: 70 parts natural rubber, 30 parts 1,4-trans polyisoprene rubber, 20 parts silica, 10 parts silica, 20 parts carbon black, 5 parts carbon black (N330), 2 parts silane coupling agent (Si-69), 2 parts stearic acid, 3 parts zinc oxide, 1 part antioxidant (4010NA), 1 part antioxidant (RD), 1.6 parts accelerator (CZ), 3 parts naphthenic oil, and 3 parts sulfur.

[0061] The performance test of the low rolling resistance and low temperature rise tire tread rubber material obtained in this embodiment was conducted by replacing all the carbon black in the formulation of Example 2 with silica as the formulation of Comparative Example 3: 70 parts natural rubber, 30 parts 1,4-trans polyisoprene rubber, 20 parts silica, 30 parts silica, 7.5 parts silane coupling agent (Si-69), 2 parts stearic acid, 3 parts zinc oxide, 1 part antioxidant (4010NA), 1 part antioxidant (RD), 1.6 parts accelerator (CZ), 3 parts naphthenic oil, and 3 parts sulfur. The silica in Example 2 was completely replaced with carbon black to form the formulation of Comparative Example 4: 70 parts natural rubber, 30 parts 1,4-trans polyisoprene rubber, 20 parts silica, 30 parts carbon black, 5 parts silane coupling agent (Si-69), 2 parts stearic acid, 3 parts zinc oxide, 1 part antioxidant (4010NA), 1 part antioxidant (RD), 1.6 parts accelerator (CZ), 3 parts naphthenic oil, and 3 parts sulfur.

[0062] Following the process described in Example 1, rubber samples from Example 2, Comparative Examples 3 and 4 were prepared for performance testing. The testing methods were the same as in Example 1, as shown in the table below:

[0063] Test Project Comparative Example 3 Comparative Example 4 Example 2 Mooney viscosity / MU 41.36 36.89 39.20 100% constant tensile stress / MPa 3.26 2.76 3.43 300% constant tensile stress / MPa 12.25 10.32 11.93 Tensile strength / MPa 15.6 17.8 19.3 Elongation at break / % 482 599 543 ΔG' / KPa 207.42 128.71 148.45 tanδ@60℃ 0.11 0.12 0.09 Surface temperature rise / °C 21.5 27.9 15.7 Core temperature rise / ℃ 34.6 48.5 29.8 <![CDATA[Wear volume / cm 3 / 1.61 km]]> 0.11 0.18 0.13

[0064] As can be seen from the table, the Mooney viscosity of Example 2 is between that of Comparative Example 3 (without carbon black) and Comparative Example 4 (without silica). Due to the dispersion problem of silica in the rubber matrix, the tensile strength and elongation at break of Comparative Example 3 are both lower than those of Example 2, and ΔG ’ The larger value indicates poor dispersion of silica in the presence of 1,4-trans-polyisoprene rubber crystals. In contrast, the filler in Comparative Example 4, which does not contain silica, exhibits better dispersion. In Example 2, tanδ@60℃ is lower than that in Comparative Examples 3 and 4, indicating that the rubber compound in Example 2 has lower rolling resistance when used in the tire tread. This demonstrates that the silica / carbon black / silica composite filler system is more effective in reducing tire rolling resistance than the silica / carbon black system and the silica / silica composite filler system alone. Compared to Comparative Example 3, the rubber compound wear in Comparative Example 4 and Example 2 is increased, indicating that increasing the amount of silica can significantly reduce rubber compound wear. The surface and center temperature rise in Example 2 are significantly lower than those in Comparative Examples 3 and 4, proving that proper control of the silica / carbon black / silica composite filler system can reduce heat generation on the tire tread under alternating loads, thus ensuring tire performance and extending service life.

[0065] Example 3

[0066] The low rolling resistance and low temperature rise tire tread material involved in this embodiment includes the following components by weight: 60 parts natural rubber, 40 parts 1,4-trans polyisoprene rubber, 10 parts silica, 10 parts silica, 30 parts carbon black (N330), 5 parts silane coupling agent (Si-69), 2 parts stearic acid, 3 parts zinc oxide, 1 part antioxidant (4010NA), 1 part antioxidant (RD), 1.6 parts accelerator (CZ), 3 parts naphthenic oil, and 3 parts sulfur.

[0067] Example 4

[0068] The low rolling resistance and low temperature rise tire tread compound material involved in this embodiment includes the following components by weight: 70 parts natural rubber, 30 parts 1,4-trans polyisoprene rubber, 30 parts silica, 10 parts silica, 10 parts carbon black, 10 parts carbon black (N330), 5 parts silane coupling agent (Si-69), 2 parts stearic acid, 3 parts zinc oxide, 1 part antioxidant (4010NA), 1 part antioxidant (RD), 1.6 parts accelerator (CZ), 3 parts naphthenic oil, and 3 parts sulfur.

[0069] Following the process described in Example 1, rubber samples from Examples 3 and 4 were prepared for performance testing, as shown in the table below:

[0070]

[0071]

[0072] As can be seen from the table, the Mooney viscosity of Examples 3 and 4 increases with the increase of the proportion of 1,4-trans-polyisoprene rubber, while the addition of silica decreases the Mooney viscosity. Furthermore, with the increase of the proportion of 1,4-trans-polyisoprene rubber, the 100% elongation stress, 300% elongation stress, and tensile strength in Examples 3 and 4 are slightly higher than those in Comparative Examples 2 and 4, while the elongation at break is at the same level due to the difference in silica content. In Examples 3 and 4, the filler dispersibility is weaker than that of Comparative Example 4 with the silica / carbon black system, but compared with Comparative Example 2, the addition of silica improves the filler dispersibility. The tanδ@60℃ values ​​in Examples 3 and 4 are not greater than those in Comparative Examples 2 and 4, indicating that Examples 3 and 4 have lower rolling resistance when applied to tread rubber; moreover, the tanδ@60℃ of Example 4 is smaller than that of Examples 3 and 2, indicating that increasing the silica proportion can reduce the rolling resistance of the tread rubber. Compared with Comparative Example 2 and Example 3, the rubber wear in Example 4 was reduced, indicating that increasing the amount of silica can significantly reduce rubber wear. The surface and center temperature rises in Examples 3 and 4 were significantly lower than those in Comparative Example 2 and Example 4, and the temperature rise decreased more noticeably with increasing silica ratio in the experiment. This demonstrates that proper control of the crystallization of 1,4-trans-polyisoprene rubber and the silica ratio can ensure that the tire tread has both low rolling resistance and low heat generation under alternating loads, thus guaranteeing tire performance and extending service life.

Claims

1. A low rolling resistance, low temperature rise tire tread compound material, characterized in that, The product comprises the following components in parts by weight: 20-40 parts of 1,4-trans-polyisoprene rubber, 60-80 parts of natural rubber, 10-30 parts of silica, 10-30 parts of carbon black, 5-20 parts of silica, 1-10 parts of silane coupling agent, 1-3 parts of stearic acid, 2-4 parts of zinc oxide, 1-3 parts of antioxidant, 1-3 parts of accelerator, 1-5 parts of naphthenic oil, and 1-4 parts of sulfur. The 1,4-trans polyisoprene rubber has a trans content of 99%, a number-average molecular weight of 100,000 to 500,000, and a molecular weight distribution index (PI) of 1.5 to 3. The silica structure includes microparticles, flakes, or stacked flakes, and its main components include 75%–91% silica and 3%–14% alumina, with a median particle size of 0.5–5 µm. The silica mentioned is nano-silica, with a DBP absorption of 165-200 ml / 100 g and a CTAB specific surface area of ​​165-200 m² / g. 2 / g; The carbon black is one or a combination of N330, N550, and N660.

2. The low rolling resistance and low temperature rise tire tread compound material according to claim 1, characterized in that, The natural rubber mentioned includes standard rubber, smoked sheet rubber, and air-dried rubber.

3. The low rolling resistance and low temperature rise tire tread compound material according to claim 1, characterized in that, The stearic acid mentioned is octadecanoic acid; The antioxidant is one or a combination of antioxidant 4020, antioxidant 4010, antioxidant 4010NA, and antioxidant RD; The accelerator is one or a combination of several of the following: accelerator DPG, accelerator CZ, accelerator TMTD, and accelerator DM.

4. The low rolling resistance and low temperature rise tire tread compound material according to claim 1, characterized in that, The silane coupling agent is one or a combination of several of KH550, KH560, and Si-69.

5. A method for preparing a low rolling resistance, low temperature rise tire tread compound material as described in claim 1, characterized in that, Includes the following steps: S1, Mixing S11) Plasticize natural rubber on an open mill with a roller temperature of 25~35℃ and a roller gap of 0.35~1.0mm, and make triangular wraps 10~15 times. S12) Plasticize 1,4-trans-polyisoprene rubber on an open mill with a roller temperature of 50℃~60℃ and a roller gap of 0.3~1.0mm, and make triangular wraps 10~15 times. S13) Add the plasticized 1,4-trans-polyisoprene rubber to the natural rubber wrapped on the roller at a roller temperature of 45~60℃ and mix evenly. S14) Add zinc oxide, stearic acid, accelerator, and antioxidant in sequence. After each addition of an auxiliary material, tap the rubber once on each side. S15) Add silica and fumed silica in small batches. After each addition, cut the rubber on each side. Once the mixture is even, add the silane coupling agent in small batches and mix for 3-5 minutes. S16) Add carbon black in batches and small amounts. After each addition, cut the rubber on both sides once. After the carbon black is completely and evenly mixed, add naphthenic oil and sulfur. After mixing evenly, adjust the roller gap to 0.3~1.0mm and make a thin triangular wrap 10~15 times. Then adjust the roller gap to 2~3mm and determine the calendering direction to produce the sheet. S17) The compound obtained in step S16) is left to stand at 25℃~30℃ for 12~18 hours; S2, sulfurization The compound obtained in step S17) is vulcanized at a vulcanization temperature of 140~150℃ and a vulcanization pressure of 30~40Mpa. The vulcanization time is the positive vulcanization time measured by a vulcanizer at the corresponding temperature. After vulcanization, the sample is left at room temperature for 10~20 hours to obtain the product.

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