Long-acting crack-resistant off-the-road tire sidewall rubber composition

Abstract

The invention discloses a long-acting crack-resistant sidewall rubber composition for an off-the-road tire, and relates to the technical field of tires. According to the technical scheme, the rubber composition comprises the following components in parts by weight: 100 parts of a rubber component, 43-53 parts of carbon black, 5-10 parts of processing oil, 2-4 parts of tackifying resin, 1-2 parts of a rubber cracking prevention agent DH-175, 2-4 parts of an anti-reversion agent DC-273, 4-6 parts of an anti-aging agent, 1-2 parts of protective wax, 3-5 parts of zinc oxide, 1-2 parts of stearic acid, 1.3-1.8 parts of sulfur, 1.4-1.8 parts of an accelerant and 0.1-0.2 part of a scorch retarder. The invention overcomes the problem of insufficient flexural aging resistance of the existing tire sidewall rubber material, and provides the long-acting and cracking-resistant sidewall rubber composition for the off-the-road tire, which can be used for a long time in a high-heat and high-ultraviolet scene, so that the flexural aging resistance of the sidewall rubber is greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of tires, and in particular to a long-lasting crack-resistant engineering machinery tire sidewall rubber composition. Background Art

[0002] Tires are an important part of automobiles, and the quality of their rubber is directly related to the service life of tires and the safety of automobile driving. With the development of technology, the requirements for the aging resistance of tire rubber are getting higher and higher, especially in the sidewalls and other parts that are frequently bent and strongly affected by light, the aging performance is particularly important. A large number of cracks will appear on the sidewalls after aging, which will not only cause customer complaints, but also bring serious safety hazards as the cracks continue to grow, which can easily lead to problems such as tire blowouts. Therefore, it is particularly important to provide a sidewall rubber with better aging resistance. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the problem of insufficient flexural aging resistance of existing tire sidewall rubber materials, and to provide a long-lasting, crack-resistant engineering machinery tire sidewall rubber composition that can be used for a long time in high-heat and high-ultraviolet scenes, thereby greatly improving the flexural aging resistance of the sidewall rubber.

[0004] The technical solution of the present invention is:

[0005] A long-lasting crack-resistant engineering machinery tire sidewall rubber composition comprises the following components in parts by weight: 100 parts of a rubber component, 43-53 parts of carbon black, 5-10 parts of a processing oil, 2-4 parts of a tackifying resin, 1-2 parts of a rubber crack preventing agent DH-175, 2-4 parts of an anti-vulcanization reversion agent DC-273, 4-6 parts of an antioxidant, 1-2 parts of a protective wax, 3-5 parts of zinc oxide, 1-2 parts of stearic acid, 1.3-1.8 parts of sulfur, 1.4-1.8 parts of an accelerator, and 0.1-0.2 parts of a scorch retarder.

[0006] Among them, the rubber crack prevention agent DH-175 1-2 parts is mainly composed of a mixture of refined paraffin and protective wax, a product of Wuxi Dongcai Technology Co., Ltd.; the anti-sulfurization reversion agent DC-273 2-4 parts is a pungent soap mixture composed by optimized design, a product of Wuxi Dongcai Technology Co., Ltd.

[0007] Preferably, the rubber component is 40-50 parts of natural rubber and 50-60 parts of butadiene rubber.

[0008] Preferably, the carbon black is N375 or N347 carbon black.

[0009] Preferably, the tackifying resin is phenolic resin SP1068 or SL1801.

[0010] Preferably, the processing oil is environmentally friendly oil.

[0011] Preferably, the antioxidant is ketoamine antioxidant RD and p-phenylenediamine antioxidant 4020.

[0012] Preferably, the accelerator is a sulfenamide accelerator NS.

[0013] Preferably, the anti-scorch agent is a highly active anti-scorch agent CTP.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] Compared with the existing tire sidewall rubber, the present invention adds an additional rubber cracking inhibitor DH-175 on the basis of the original anti-aging system. The rubber has a wider range of carbon number distribution and can be used with protective wax to ensure that the sidewall still has a good UV resistance effect for a very long time, delay the aging process of the rubber, and reduce the occurrence of cracks. In addition, the anti-reversion agent DC-273 participates in the vulcanization reaction to form a stable cross-linking bond, enhance the anti-reversion performance of the rubber, and maintain the physical properties of the rubber even under high temperature and multiple flexing conditions. The synergistic effect of these two materials under static and dynamic protection is crucial to improving the durability and stability of the sidewall rubber in high heat and high UV environments, and can significantly extend the service life of the tire. DETAILED DESCRIPTION

[0016] In order to enable persons skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

[0017] Examples 1-3 and Comparative Examples 1-3

[0018] The sidewall rubber formulations of Examples 1-3 and Comparative Examples 1-3 are shown in Table 1:

[0019] Table 1 Sidewall rubber formulations of Examples 1-3 and Comparative Examples 1-3

[0020]

[0021]

[0022] The preparation method of the sidewall rubber of Examples 1-3 and Comparative Examples 1-3 comprises the following steps:

[0023] S1 one-stage mixing

[0024] First, put 20# standard rubber, BR9000, half of N375 carbon black, zinc oxide, stearic acid, antioxidant 4020 and RD, rubber cracking inhibitor DH-175, tackifying resin SL-1801, and protective wax into the internal mixer at the same time, maintain the speed at 43r / min, mix for 30s, raise the top bolt, add the remaining N375 carbon black, continue to mix under pressure for 40s, raise the top bolt, add environmentally friendly oil, press the top bolt and mix to 135℃, raise the top bolt, mix under pressure to 150℃ to discharge the rubber; after cooling and placing for 5h, a masterbatch is obtained, and then final mixing is carried out;

[0025] S2 Final Refining

[0026] The masterbatch of step S1 and sulfur, anti-reversion agent DC-273, accelerator NS, and anti-scorch agent CTP are simultaneously put into an internal mixer, the speed is maintained at 29r / min, and the mixture is pressurized and mixed. The mixture is lifted and pressed every 30s. After repeating 4 times, the rubber is discharged and sliced. After being left to cool, the high-efficiency and aging-resistant sidewall rubber is obtained.

[0027] The sidewall rubbers of the engineering machinery tires prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to high temperature vulcanization to prepare test samples, and then performance tests were performed. The test results are shown in Table 2:

[0028] Table 2 Performance test results of engineering machinery tire sidewall rubber prepared in Examples 1-3 and Comparative Examples 1-3

[0029]

[0030]

[0031] Test sample vulcanization conditions: 147℃×60min; aging test conditions: 100℃×48h.

[0032] Ozone cracking resistance test conditions: temperature 60°C, relative humidity 50%RH, ozone concentration 200ppHm, static tensile strain 20%, time 230h.

[0033] By comparing Example 1 with Comparative Example 1, it can be seen that by adding rubber crack prevention agent DH-175 and anti-vulcanization reversion agent DC-273 to the rubber compound at the same time, the hardness, tensile stress, tensile strength, elongation at break and other properties of the rubber compound do not change much; the tear strength is increased by 20%; the ozone crack resistance is significantly improved, the flexural crack growth is increased by about 47%, and the aging resistance is significantly improved.

[0034] By comparing Example 1 with Comparative Examples 2-3, it can be seen that adding the rubber crack prevention agent DH-175 and the anti-reversion agent DC-273 to the rubber formula at the same time has a more obvious improvement effect in tear strength, ozone resistance and flex crack resistance compared to the rubber compound with only one of the materials added, and the advantages are more obvious.

[0035] In summary, the application of anti-reversion agent DC-273 and rubber cracking inhibitor DH-175 in rubber materials can significantly improve the tear resistance, ozone aging resistance and flexural aging resistance of rubber materials. The mechanism of action of these two materials is as follows:

[0036] 1. Tear resistance: The anti-reversion agent DC-273 optimizes the cross-linking network of rubber through its unique chemical structure, changes the cross-linking bond structure formed during the vulcanization of the rubber, enhances the cohesion of the rubber and the uniformity of stress distribution, and improves the heat-resistant oxygen stability of the rubber, thereby giving the vulcanized rubber good anti-reversion properties. At the same time, it helps to improve the tear resistance of the rubber, because the more stable cross-linking bonds can better disperse and withstand the tearing stress when the material is subjected to tearing force, delaying the expansion of cracks. Rubber cracking inhibitor DH-175 gradually migrates to the surface of the product after vulcanization to form a dense protective film, which not only has a shielding effect on ozone, but also enhances the tear resistance of rubber. The existence of the protective film makes it difficult for cracks to penetrate the dense protective layer, and the crack expansion path becomes more complicated, increasing the resistance to crack expansion.

[0037] 2. Ozone aging resistance: Rubber cracking prevention agent DH-175 contains a wide range of carbon number distribution, which can maintain a certain spray volume in a wide temperature range, forming a protective film, effectively shielding the damage of ozone to rubber, and at the same time capturing and neutralizing ozone molecules to prevent them from reacting with unsaturated bonds in rubber, thereby delaying the aging process, meeting the needs of rubber to resist ozone aging in various temperature ranges, reducing cracks and aging caused by ozone, and extending the service life of rubber materials; Anti-vulcanization reversion agent DC-273 indirectly enhances the material's ozone resistance by improving the thermal oxygen stability of rubber. It improves the chemical stability of rubber and reduces the oxidation reaction caused by ozone by changing the structure of cross-linking bonds.

[0038] 3. Flex aging resistance: Anti-reversion agent DC-273 helps reduce heat generation and wear under dynamic conditions (such as repeated flexing) by reducing the Mooney viscosity of the rubber and improving the fluidity of the rubber, thereby improving the flex aging resistance. Lower heat generation means less thermal degradation of the material during repeated deformation, maintaining the elasticity and structural integrity of the rubber; the protective film of rubber crack prevention agent DH-175 is also beneficial to flex aging resistance, because the film layer can reduce surface damage and crack formation caused by flexing, and protect the internal structure of the rubber from external factors.

[0039] When these two materials are used together, their mechanisms of action complement each other and produce a synergistic effect. Anti-reversion agent DC-273 improves the overall performance of the material by optimizing the cross-linking structure and reducing heat generation, while rubber cracking inhibitor DH-175 forms a protective layer on the surface to prevent erosion by external factors such as ozone. This synergistic effect significantly improves the performance of rubber materials in terms of tear resistance, ozone resistance and flex aging resistance, providing an efficient and reliable solution for improving the performance of sidewall rubber.

Claims

1. A long-lasting crack-resistant engineering machinery tire sidewall rubber composition, characterized in that: The invention comprises the following components in parts by weight: 100 parts of rubber component, 43-53 parts of carbon black, 5-10 parts of processing oil, 2-4 parts of tackifying resin, 1-2 parts of rubber crack preventing agent DH-175, 2-4 parts of anti-reversion agent DC-273, 4-6 parts of antioxidant, 1-2 parts of protective wax, 3-5 parts of zinc oxide, 1-2 parts of stearic acid, 1.3-1.8 parts of sulfur, 1.4-1.8 parts of accelerator and 0.1-0.2 parts of scorch retarder.

2. The long-lasting crack-resistant engineering machinery tire sidewall rubber composition according to claim 1, characterized in that: The rubber component comprises 40-50 parts of natural rubber and 50-60 parts of butadiene rubber.

3. The long-lasting crack-resistant engineering machinery tire sidewall rubber composition according to claim 1, characterized in that: The carbon black is N375 or N347 carbon black.

4. The long-lasting crack-resistant engineering machinery tire sidewall rubber composition according to claim 1, characterized in that: The tackifying resin is phenolic resin SP1068 or SL1801.

5. The long-lasting crack-resistant engineering machinery tire sidewall rubber composition according to claim 1, characterized in that: The processing oil is environmentally friendly oil.

6. The long-lasting crack-resistant engineering machinery tire sidewall rubber composition according to claim 1, characterized in that: The antioxidants are ketoamine antioxidant RD and p-phenylenediamine antioxidant 4020.

7. The long-lasting crack-resistant engineering machinery tire sidewall rubber composition according to claim 1, characterized in that: The accelerator is a sulfonamide accelerator NS.

8. The long-lasting crack-resistant engineering machinery tire sidewall rubber composition according to claim 1, characterized in that: The anti-scorch agent is a highly active anti-scorch agent CTP.

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