Long-fatigue-life rubber compound for air spring and preparation method of long-fatigue-life rubber compound

Abstract

The invention relates to the technical field of air spring materials, and particularly discloses a long-fatigue-life rubber compound for an air spring and a preparation method of the long-fatigue-life rubber compound. The invention discloses a rubber compound with long fatigue life. The rubber compound is prepared from the following components: rubber, high-wear-resistance carbon black, semi-reinforcing carbon black, white carbon black, naphthenic oil, zinc oxide, stearic acid, an anti-aging agent, bimodal wax, sulfur and an accelerant. The rubber is formed by mixing natural rubber and butadiene rubber; the anti-aging agent is prepared from a quinoline anti-aging agent RD, an amine anti-aging agent 4020, an amine anti-aging agent 6PPD, an amine anti-aging agent 3100, a phenol anti-aging agent 2246 and Mg-Al layered double hydroxide; the accelerant is formed by mixing an accelerant CZ and an accelerant DTDM. By utilizing the technical scheme provided by the invention, the rubber compound with excellent fatigue resistance, thermo-oxidative aging resistance and ozone aging resistance is prepared.

Description

Technical Field

[0001] The present application relates to the technical field of air spring materials, and in particular to a high fatigue life rubber compound for air springs and a preparation method thereof. Background Art

[0002] Air springs, as a key component with support, shock absorption and buffering functions, are widely used in commercial vehicles, construction machinery, rail transit and other fields. At present, natural rubber (NR) is still a common base material for air spring compounds due to its excellent elasticity and low cost. However, it has obvious shortcomings in actual use: Insufficient fatigue performance: Air springs need to be repeatedly inflated and deflated during operation and withstand dynamic loads (such as bumps and vibrations during vehicle driving). The unsaturated double bonds in the NR molecular chain are easily broken under long-term stress, resulting in a decrease in the elasticity of the compound, cracks, and a generally short fatigue life. Poor environmental adaptability: Under conditions of high temperature and ozone, NR undergoes rapid thermal oxidation aging and ozone aging, which manifests as rubber hardening and cracking, further shortening the service life of the air spring and even causing safety hazards such as leakage and failure. Summary of the Invention

[0003] In order to solve the above technical problems, the present application provides a high fatigue life rubber compound for air springs and a preparation method thereof.

[0004] In a first aspect, the present application provides a high fatigue life rubber compound for air springs, which is prepared from the following components in parts by weight: 100 parts of rubber, 20-40 parts of high wear-resistant carbon black, 10-30 parts of semi-reinforcing carbon black, 3-10 parts of white carbon black, 3-10 parts of naphthenic oil, 4-8 parts of zinc oxide, 0.5-1.5 parts of stearic acid, 5-15 parts of antioxidant, 1-3 parts of bimodal wax, 1.5-3 parts of sulfur, and 1-3 parts of accelerator; The rubber is composed of a mixture of natural rubber and butadiene rubber in a weight ratio of 7-9:1-3; The antioxidant is composed of a mixture of quinoline antioxidant RD, amine antioxidant 4020, amine antioxidant 6PPD, amine antioxidant 3100, phenolic antioxidant 2246, and Mg-Al layered double hydroxide in a weight ratio of 1-3:1-3:1-3:1-3:1-3:0.1-0.5; The accelerator is composed of a mixture of accelerator CZ and accelerator DTDM in a weight ratio of 0.5-1.5:0.5-1.5.

[0005] The technical solution adopted in this application aims to construct a "rubber-antiaging agent-protective wax synergistic protection system" to solve the problems of mixed rubber properties, resistance to thermal oxidation aging, and resistance to ozone aging.

[0006] Among rubbers, BR has highly regular and flexible molecular chains, and its unsaturated double bonds are more evenly distributed. This allows the chains to slide and rearrange more smoothly under repeated deformation (fatigue conditions), minimizing stress concentration and making crack propagation due to localized chain breakage less likely. However, BR has poor tear resistance and inferior processing performance to NR (due to higher heat generation). Therefore, using a combination of natural rubber and BR in a certain ratio can achieve a balanced performance by leveraging BR's improved fatigue performance while retaining NR's tear resistance, resistance to thermal and ozone aging, and processing advantages.

[0007] This application adopts a synergistic scheme of main and auxiliary antioxidants in the anti-aging system of the air spring, designed for its dynamic working conditions and complex environment, by constructing an antioxidant / Mg-Al layered double hydroxide hybrid dispersion system: the antioxidant can be embedded in the interlayer of the Mg-Al layered double hydroxide through ion exchange, and the active ingredients are slowly released at high temperature to capture free radicals. The metal itself has antioxidant activity, which synergistically improves heat resistance with the organic antioxidant. Quinoline antioxidant RD focuses on resistance to thermal oxidation and dynamic fatigue aging, and stabilizes the rubber structure; amine antioxidants 4020, 6PPD, and 3100 focus on scavenging free radicals and quickly consuming ozone, among which 4020 and 6PPD are more resistant to ozone, and 3100 also takes into account resistance to flexural aging; phenolic antioxidant 2246, on the one hand, can decompose peroxides produced by amine reactions, avoid secondary oxidation, and extend the life of the main agent; on the other hand, it can reduce discoloration caused by amine oxidation, taking into account the appearance; in terms of synergistic effect, quinoline and amine antioxidants form a "structural stability-active protection" complement, and phenols "clean up by-products" to strengthen protection, ultimately reducing the rate of thermal oxidation aging, delaying ozone cracking, and meeting the long-term use needs of air springs.

[0008] Bimodal wax acts as a physical barrier. The protective wax can form a uniform wax film on the surface of the rubber compound through migration, acting like an "outer shield" to block ozone molecules from directly invading the interior of the rubber compound, reducing the probability of contact between ozone and rubber molecules. Especially in static or low-stress states, it can quickly build a first line of defense. Bimodal wax has a special carbon number distribution, containing a relatively large number of low-carbon atomic components and a certain amount of high-carbon atomic components. At low temperatures, low-carbon alkanes can quickly migrate to the rubber surface to form a protective film; at high temperatures, high-carbon alkane components can gradually precipitate to play a protective role, ensuring long-term protective effects. Combined with the rationality of the carbon number distribution and compatibility with rubber, as well as reasonable addition amount and process control, a uniform and dense protective film can be formed on the rubber surface, thereby providing ozone protection for the product over the entire temperature range, especially suitable for the protection needs of air springs under different temperature fluctuation conditions.

[0009] This application utilizes a "rubber-antioxidant-protective wax synergistic protection system" that synergistically achieves dual protection through "physical barrier + chemical removal": the wax film reduces ozone erosion efficiency through physical barrier, while the anti-aging system simultaneously counteracts penetrating ozone and thermal oxygen aging. The two form a closed-loop protection system that collectively minimizes the risk of ozone cracking and thermal oxygen aging. This system is more suitable for the long-term use requirements of air springs under complex operating conditions.

[0010] Preferably, the high fatigue life rubber compound is prepared from the following components in parts by weight: 100 parts of rubber, 25-35 parts of high wear-resistant carbon black, 15-25 parts of semi-reinforcing carbon black, 5-7 parts of white carbon black, 5-7 parts of naphthenic oil, 5-7 parts of zinc oxide, 0.7-1.2 parts of stearic acid, 7-13 parts of antioxidant, 1.5-2.5 parts of bimodal wax, 1.8-2.6 parts of sulfur, and 1.5-2.5 parts of accelerator.

[0011] Preferably, the rubber is composed of a mixture of natural rubber and butadiene rubber in a weight ratio of 7.5-8.5:1.5-2.5.

[0012] In a specific embodiment, the rubber is composed of a mixture of natural rubber and butadiene rubber in a weight ratio of 8:2.

[0013] Preferably, the antioxidant is composed of a mixture of quinoline antioxidant RD, amine antioxidant 4020, amine antioxidant 6PPD, amine antioxidant 3100, phenolic antioxidant 2246, and Mg-Al layered double hydroxide in a weight ratio of 1-2:2-3:1-2:1-2:2-3:0.2-0.4.

[0014] In a specific embodiment, the antioxidant is composed of a mixture of quinoline antioxidant RD, amine antioxidant 4020, amine antioxidant 6PPD, amine antioxidant 3100, phenolic antioxidant 2246, and Mg-Al layered double hydroxide in a weight ratio of 2:2:1:1:3:0.3.

[0015] Preferably, in the antioxidant, the Mg-Al layered double hydroxide is prepared by co-precipitation of a mixed salt solution containing 0.5-0.8 mol / L magnesium nitrate and 0.1-0.4 mol / L aluminum nitrate and an alkaline solution containing 1.5-2.5 mol / L sodium nitrate and 2.0-3.0 mol / L sodium hydroxide.

[0016] Preferably, in the antioxidant, the preparation method of the Mg-Al layered double hydroxide is as follows: under stirring conditions of 500-1000 rpm, a mixed salt solution containing 0.5-0.8 mol / L magnesium nitrate and 0.1-0.4 mol / L aluminum nitrate and an alkali solution containing 1.5-2.5 mol / L sodium nitrate and 2.0-3.0 mol / L sodium hydroxide are added dropwise to a reactor at a constant flow rate of 1-2 mL / min; the pH is maintained at 9.5-10.0 and the reaction temperature is maintained at 25-40°C throughout the process; after the addition is completed, static aging is carried out at 60-70°C for 18-24 hours to obtain a slurry; and then the slurry is centrifuged, filtered, washed with water until neutral, and dried at 70-90°C.

[0017] Preferably, the preparation method of the antioxidant is as follows: pre-mixing the raw materials according to the ratio, and preparing the antioxidant by banburying at 100-140° C. and 100-200 rpm for 10-20 minutes.

[0018] Preferably, the accelerator is composed of a mixture of accelerator CZ and accelerator DTDM in a weight ratio of 0.5-1.0:1.0-1.5.

[0019] In a specific embodiment, the accelerator is composed of a mixture of accelerator CZ and accelerator DTDM in a weight ratio of 0.8:1.2.

[0020] In a second aspect, the present application provides a method for preparing the high fatigue life rubber compound, which specifically comprises the following steps in sequence: (1) Add natural rubber to the internal mixer for plastication, open the mixer to produce sheets, cool and then leave for 24-72 hours; (2) Add butyl rubber, zinc oxide, stearic acid, antioxidant, bimodal wax and sulfur to the plasticized natural rubber according to the formula ratio, mix them at a temperature of 60-80℃ for 40-60s, and then raise the top bolt; (3) Then add high wear-resistant carbon black, semi-reinforced carbon black, white carbon black and naphthenic oil, and mix at a temperature of 120-140 ° C for 60-90 seconds, discharge the material, and raise the top plug 1-2 times in the middle to volatilize some small molecular organic matter; (4) Thinly pass the material on the open mill, and the sheet is discharged from the open mill to obtain the rubber compound; (5) Cool the above rubber compound to room temperature and leave it for more than 8 hours to obtain a masterbatch; (6) Add the above masterbatch into the internal mixer, add the accelerator according to the formula ratio, mix for 100-150s, and discharge when the temperature is ≤100℃; (7) Thinning and producing strips on the open mill; (8) After cooling to 20-25℃, let it stand for 16-24 hours to obtain the finished product.

[0021] In a third aspect, the present application provides the use of the above-mentioned high fatigue life rubber compound in the preparation of air springs.

[0022] In summary, the technical solution of this application has the following effects: The rubber compound provided in this application and solution achieves significant improvements in air spring performance through a rational ratio of natural rubber to butadiene rubber, a compounded antioxidant system, and the application of bimodal wax: fatigue life is significantly increased, reaching 10 million cycles; resistance to thermal oxidative aging is significantly improved, with minimal changes in tensile strength and elongation at break after aging at 85°C for 72 hours; resistance to ozone aging is significantly enhanced, with no cracking after aging at 100 pphm at 40°C for 72 hours at 20% tension; and enhanced temperature protection allows for use at -40°C to 80°C. These improvements effectively address the rapid aging and fatigue susceptibility of natural rubber, significantly improving the reliability and service life of air springs, reducing maintenance costs, and enhancing product market competitiveness. DETAILED DESCRIPTION

[0023] The present application is further described in detail below in conjunction with examples, comparative examples and performance testing experiments. These examples should not be construed as limiting the scope of protection claimed in this application. Example Examples 1-5

[0024] Examples 1-5 respectively provide a high fatigue life rubber compound and a preparation method thereof.

[0025] The difference between the above embodiments is that the amount of each component in the high fatigue life rubber compound is different, as shown in Table 1.

[0026] The preparation method of the Mg-Al layered double hydroxide in the above embodiment is specifically as follows.

[0027] Prepare the solution: dissolve magnesium nitrate hexahydrate and aluminum nitrate nonahydrate in deionized water to obtain a mixed salt solution containing 0.7 mol / L magnesium nitrate and 0.2 mol / L aluminum nitrate; dissolve sodium nitrate and sodium hydroxide in deionized water to obtain an alkaline solution containing 2.0 mol / L sodium nitrate and 2.5 mol / L sodium hydroxide.

[0028] Under stirring conditions of 800 rpm, the mixed salt solution and the alkaline solution are dripped into the reactor in parallel at 1.5 mL / min through a constant flow pump; the pH is maintained at 9.5-10.0 and the reaction temperature is 30°C throughout the process; after the addition is completed, static aging is carried out at 65°C for 20 hours to promote crystal growth to obtain a slurry; the slurry is centrifuged, filtered, washed with water to neutrality, and dried at 80°C to constant weight.

[0029] The preparation method of the antioxidant is as follows: quinoline antioxidant RD, amine antioxidant 4020, amine antioxidant 6PPD, amine antioxidant 3100, phenolic antioxidant 2246, and Mg-Al layered double hydroxide are pre-mixed in a weight ratio of 2:2:1:1:3:0.3 in an internal mixer, and the mixture is prepared by internal mixing at 120°C and 160 rpm for 15 minutes.

[0030] The preparation method of the high fatigue life rubber compound in the above embodiment is specifically as follows.

[0031] (1) Add natural rubber to the internal mixer for plastication, open the mixer to produce sheets, cool and package, and then leave for 48 hours; (2) Add the plasticized natural rubber, butadiene rubber, zinc oxide, stearic acid, antioxidant, bimodal wax, and sulfur into the internal mixer according to the formula ratio, mix them at 70℃ for 50s, and then raise the top bolt; (3) Add high wear-resistant carbon black, semi-reinforced carbon black, white carbon black and naphthenic oil into the internal mixer, mix to 130℃ and discharge the material, raise the top bolt twice in the middle to volatilize some small molecular organic matter; (4) Thinly pass the material on the open mill, and the sheet is discharged from the open mill to obtain the rubber compound; (5) Cool the above rubber compound to room temperature and leave it for more than 8 hours to obtain a masterbatch; (6) Add the above masterbatch into the internal mixer, and add the accelerator according to the formula ratio (the accelerator is composed of a mixture of accelerator CZ and accelerator DTDM with a weight ratio of 0.8:1.2), mix for 120s, and discharge when the temperature is ≤100℃; (7) Thinning and producing strips on the open mill; (8) Cool to 22°C and let stand for 20 hours to obtain the finished product.

[0032] Table 1 Amount of each component in the high fatigue life rubber compound in Examples 1-5 and Comparative Examples 1-2 Examples 6-9

[0033] Examples 6-9 respectively provide a high fatigue life rubber compound and a preparation method thereof.

[0034] The difference between the above embodiment and embodiment 1 is that the weight ratio of natural rubber to butadiene rubber is different, as shown below.

[0035] In Example 6, the weight ratio of natural rubber to butadiene rubber is 70g:30g.

[0036] In Example 7, the weight ratio of natural rubber to butadiene rubber is 90 g:10 g.

[0037] In Example 8, the weight ratio of natural rubber to butadiene rubber is 75g:25g.

[0038] In Example 9, the weight ratio of natural rubber to butadiene rubber is 85 g:15 g.

[0039] The other process parameters in the above embodiment are the same as those in Example 1. Examples 10-14

[0040] Examples 10-14 respectively provide a high fatigue life rubber compound and a preparation method thereof.

[0041] The difference between the above embodiment and embodiment 1 is that the types of antioxidants are different, as shown below.

[0042] In Example 10: The preparation method of Mg-Al layered double hydroxide is as follows: under stirring conditions of 800 rpm, a mixed salt solution containing 0.2 mol / L magnesium nitrate and 0.7 mol / L aluminum nitrate and an alkali solution are added dropwise to the reactor at 1.5 mL / min through a constant flow pump; the pH is maintained at 9.5-10.0 and the reaction temperature is 30°C throughout the process; after the addition is completed, static aging is carried out at 65°C for 20 hours to promote crystal growth to obtain a slurry; the slurry is centrifuged, filtered, washed with water to neutrality, and dried at 80°C to constant weight.

[0043] In Example 11: The preparation method of Mg-Al layered double hydroxide is as follows: under stirring conditions of 800 rpm, a mixed salt solution containing 0.5 mol / L magnesium nitrate and 0.4 mol / L aluminum nitrate and an alkali solution are added dropwise to a reactor at 1.5 mL / min through a constant flow pump; the pH is maintained at 9.5-10.0 and the reaction temperature is 30°C throughout the process; after the addition is completed, static aging is carried out at 65°C for 20 hours to promote crystal growth to obtain a slurry; the slurry is centrifuged, filtered, washed with water to neutrality, and dried at 80°C to constant weight.

[0044] In Example 12: The preparation method of Mg-Al layered double hydroxide is as follows: under stirring conditions of 800 rpm, a mixed salt solution containing 0.8 mol / L magnesium nitrate and 0.1 mol / L aluminum nitrate and an alkali solution are added dropwise to the reactor at 1.5 mL / min through a constant flow pump; the pH is maintained at 9.5-10.0 and the reaction temperature is 30°C throughout the process; after the addition is completed, static aging is carried out at 65°C for 20 hours to promote crystal growth to obtain a slurry; the slurry is centrifuged, filtered, washed with water to neutrality, and dried at 80°C to constant weight.

[0045] In Example 13: the antioxidant is composed of a mixture of quinoline antioxidant RD, amine antioxidant 4020, amine antioxidant 6PPD, amine antioxidant 3100, phenolic antioxidant 2246, and Mg-Al layered double hydroxide in a weight ratio of 1:3:2:2:2:0.2.

[0046] In Example 14, the antioxidant is composed of a mixture of quinoline antioxidant RD, amine antioxidant 4020, amine antioxidant 6PPD, amine antioxidant 3100, phenolic antioxidant 2246, and Mg-Al layered double hydroxide in a weight ratio of 3:1:3:3:1:0.5.

[0047] The other process parameters in the above embodiment are the same as those in Example 1. Comparative Example Comparative Example 1-2

[0048] Comparative Examples 1-2 respectively provide a rubber compound and a preparation method thereof.

[0049] The difference between the comparative example and Example 1 is that the amounts of the components in the high fatigue life rubber compound are different, as shown in Table 1.

[0050] The other process parameters in the above comparative example are the same as those in Example 1. Comparative Examples 3-8

[0051] Comparative Examples 3-8 respectively provide a rubber compound and a preparation method thereof.

[0052] The differences between the above comparative example and the embodiment are specifically as follows.

[0053] In Comparative Example 3, the rubber is composed of a mixture of natural rubber and chloroprene rubber in a weight ratio of 80 g:20 g.

[0054] In Comparative Example 4, the rubber is composed of a mixture of natural rubber and butadiene rubber in a weight ratio of 20 g:80 g.

[0055] In Comparative Example 5: No Mg-Al layered double hydroxide was added to the antioxidant, which was composed of a mixture of quinoline antioxidant RD, amine antioxidant 4020, amine antioxidant 6PPD, amine antioxidant 3100, and phenolic antioxidant 2246 in a weight ratio of 2:2:1:1:3.

[0056] In Comparative Example 6: In the antioxidant, an equal amount of Zn-Al layered double hydroxide is used instead of Mg-Al layered double hydroxide; the preparation method of Zn-Al layered double hydroxide is the same as that of Mg-Al layered double hydroxide.

[0057] In Comparative Example 7: Among the antioxidants, an equal amount of amine antioxidant 4010NA is used instead of amine antioxidant 4020; the antioxidant is composed of a mixture of quinoline antioxidant RD, amine antioxidant 4010NA, amine antioxidant 6PPD, amine antioxidant 3100, phenolic antioxidant 2246, and Mg-Al layered double hydroxide in a weight ratio of 2:2:1:1:3:0.3.

[0058] In Comparative Example 8: The antioxidant is composed of a mixture of quinoline antioxidant RD, amine antioxidant 4020, amine antioxidant 6PPD, amine antioxidant 3100, phenolic antioxidant 2246, and Mg-Al layered double hydroxide in a weight ratio of 4:0.5:4:5:0.5:0.3.

[0059] The other process parameters in the above comparative example are the same as those in Example 1. Performance testing part

[0060] (1) Dynamic fatigue resistance over a wide temperature range: The fatigue resistance of the rubber compound specimens was tested according to ASTM D4482. The test conditions were: temperature cycle: -40°C → 25°C → 80°C (maintain each temperature condition for 1 hour); frequency: 5 Hz, until complete fracture, and the number of cycles was recorded.

[0061] (2) Thermal oxidative aging resistance: According to ASTM D573, the changes in tensile strength and elongation at break of the rubber mix before and after aging were measured to evaluate the thermal oxidative aging resistance of the rubber mix. The test conditions were: the rubber mix was placed in an environment at a temperature of 85°C for 72 hours.

[0062] (3) Ozone aging resistance: According to the provisions of ASTM D1149, the test conditions are as follows: the rubber mix is ​​placed in an environment with an ozone concentration of 100 pphm and a temperature of 40°C for 72 hours, the sample is stretched 20% and fixed, and then the crack level of the rubber mix sample is visually observed: the number and length of cracks (according to the standard classification, level 0 is no cracks, and level 5 is severe cracks).

[0063] Test results: as shown in Table 2.

[0064] Table 2 Performance test results of the rubber compounds in the examples and comparative examples

[0065] From the test results in Table 2 above, it can be seen that the rubber compound prepared by using the technical solution provided by the present application has excellent fatigue resistance, thermal oxidation aging resistance and ozone aging resistance.

[0066] By comparing the test results of Examples 1-5 and Comparative Examples 1-2, it can be seen that the amount of each raw material component has a significant impact on the performance of the product. In Comparative Examples 1-2, the amounts of the raw materials used are not matched, and the performance of the prepared rubber compound is poor. In contrast, the present application effectively ensures the performance of the rubber compound by precisely matching the amount of each raw material component.

[0067] By comparing the test results of Examples 1, 6-9, and Comparative Examples 3-4, it can be seen that the type of rubber has a significant impact on the performance of the rubber mix. In Comparative Example 3, the rubber is composed of a mixture of natural rubber and chloroprene rubber in a weight ratio of 80g:20g, and in Comparative Example 4, the rubber is composed of a mixture of natural rubber and butadiene rubber in a weight ratio of 20g:80g. The performance of the resulting rubber mix is ​​poor. In contrast, the present application uses a mixture of natural rubber and butadiene rubber in a weight ratio of 7-9:1-3 as the rubber raw material, effectively ensuring the performance of the rubber mix.

[0068] By comparing the test results of Examples 1, 10-14, and Comparative Examples 5-8, it can be seen that the type of antioxidant has a significant impact on the performance of the rubber mix. In Comparative Example 5, no Mg-Al layered double hydroxide was added to the antioxidant; in Comparative Example 6, an equal amount of Zn-Al layered double hydroxide was used instead of Mg-Al layered double hydroxide; in Comparative Example 7, an equal amount of amine antioxidant 4010NA was used instead of amine antioxidant 4020; and in Comparative Example 8, the antioxidant was composed of a mixture of quinoline antioxidant RD, amine antioxidant 4020, amine antioxidant 6PPD, amine antioxidant 3100, phenolic antioxidant 2246, and Mg-Al layered double hydroxide in a weight ratio of 4:0.5:4:5:0.5:0.3. The performance of the rubber mix prepared was poor. In contrast, the present application comprises a mixture of quinoline antioxidant RD, amine antioxidant 4020, amine antioxidant 6PPD, amine antioxidant 3100, and phenolic antioxidant 2246 in a weight ratio of 1-3:1-3:1-3:1-3:1-3, which effectively ensures the performance of the mixed rubber.

[0069] Although the present invention has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made based on the present invention. Therefore, such modifications and improvements, which do not depart from the spirit of the present invention, are intended to be within the scope of protection claimed herein.

Claims

1. A high fatigue life rubber compound for air springs, characterized in that: It is prepared from the following components in parts by weight: 100 parts of rubber, 20-40 parts of high-wear-resistant carbon black, 10-30 parts of semi-reinforcing carbon black, 3-10 parts of white carbon black, 3-10 parts of naphthenic oil, 4-8 parts of zinc oxide, 0.5-1.5 parts of stearic acid, 5-15 parts of antioxidant, 1-3 parts of bimodal wax, 1.5-3 parts of sulfur, and 1-3 parts of accelerator; The rubber is composed of a mixture of natural rubber and butadiene rubber in a weight ratio of 7-9:1-3; The antioxidant is composed of a mixture of quinoline antioxidant RD, amine antioxidant 4020, amine antioxidant 6PPD, amine antioxidant 3100, phenolic antioxidant 2246, and Mg-Al layered double hydroxide in a weight ratio of 1-3:1-3:1-3:1-3:1-3:0.1-0.5; The accelerator is composed of a mixture of accelerator CZ and accelerator DTDM in a weight ratio of 0.5-1.5:0.5-1.

5.

2. The high fatigue life rubber compound according to claim 1, characterized in that The invention is prepared from the following components in parts by weight: 100 parts of rubber, 25-35 parts of high-wear-resistant carbon black, 15-25 parts of semi-reinforcing carbon black, 5-7 parts of white carbon black, 5-7 parts of cyclohexane oil, 5-7 parts of zinc oxide, 0.7-1.2 parts of stearic acid, 7-13 parts of antioxidant, 1.5-2.5 parts of bimodal wax, 1.8-2.6 parts of sulfur, and 1.5-2.5 parts of accelerator.

3. The high fatigue life rubber compound according to claim 1, characterized in that The rubber is composed of a mixture of natural rubber and butadiene rubber in a weight ratio of 7.5-8.5:1.5-2.

5.

4. The high fatigue life rubber compound according to claim 1, characterized in that The antioxidant is composed of a mixture of quinoline antioxidant RD, amine antioxidant 4020, amine antioxidant 6PPD, amine antioxidant 3100, phenol antioxidant 2246 and Mg-Al layered double hydroxide in a weight ratio of 1-2:2-3:1-2:1-2:2-3:0.2-0.

4.

5. The high fatigue life rubber compound according to claim 1, characterized in that: In the antioxidant, the Mg-Al layered double hydroxide is prepared by co-precipitation of a mixed salt solution containing 0.5-0.8 mol / L magnesium nitrate and 0.1-0.4 mol / L aluminum nitrate and an alkaline solution containing 1.5-2.5 mol / L sodium nitrate and 2.0-3.0 mol / L sodium hydroxide.

6. The high fatigue life rubber compound according to claim 5, characterized in that: In the antioxidant, the preparation method of the Mg-Al layered double hydroxide is as follows: under stirring conditions of 500-1000 rpm, a mixed salt solution containing 0.5-0.8 mol / L magnesium nitrate and 0.1-0.4 mol / L aluminum nitrate and an alkaline solution containing 1.5-2.5 mol / L sodium nitrate and 2.0-3.0 mol / L sodium hydroxide are dripped into a reactor at a constant flow rate of 1-2 mL / min; the pH is maintained at 9.5-10.0 and the reaction temperature is maintained at 25-40°C throughout the process; after the dripping is completed, static aging is carried out at 60-70°C for 18-24 hours to obtain a slurry; and then the slurry is centrifuged, filtered, washed with water until neutral, and dried at 70-90°C.

7. The high fatigue life rubber compound according to claim 1, characterized in that: The preparation method of the antioxidant is as follows: various raw materials are pre-mixed according to a proportion, and the mixture is prepared by banburying at 100-140° C. and 100-200 rpm for 10-20 minutes.

8. The high fatigue life rubber compound according to claim 1, characterized in that: The accelerator is composed of a mixture of accelerator CZ and accelerator DTDM in a weight ratio of 0.5-1.0:1.0-1.

5.

9. A method for preparing a high fatigue life rubber compound according to any one of claims 1 to 8, characterized in that: Specifically, the following steps are performed in sequence: (1) Add natural rubber to the internal mixer for plastication, open the mixer to produce sheets, cool and then leave for 24-72 hours; (2) Add butyl rubber, zinc oxide, stearic acid, antioxidant, bimodal wax and sulfur to the plasticized natural rubber according to the formula ratio, mix them at a temperature of 60-80℃ for 40-60s, and then raise the top bolt; (3) Then add high wear-resistant carbon black, semi-reinforced carbon black, white carbon black and naphthenic oil, and mix at a temperature of 120-140 ° C for 60-90 seconds, discharge the material, and raise the top plug 1-2 times in the middle to volatilize some small molecular organic matter; (4) Thinly pass the material on the open mill, and the sheet is discharged from the open mill to obtain the rubber compound; (5) Cool the above rubber compound to room temperature and leave it for more than 8 hours to obtain a masterbatch; (6) Add the above masterbatch into the internal mixer, add the accelerator according to the formula ratio, mix for 100-150s, and discharge when the temperature is ≤100℃; (7) Thinning and producing strips on the open mill; (8) After cooling to 20-25℃, let it stand for 16-24 hours to obtain the finished product.

10. Use of the high fatigue life rubber compound according to any one of claims 1 to 8 in the preparation of air springs.

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