High tensile strength EPDM elastomeric matting compound and method of making same

Abstract

The application relates to the technical field of rubber mixtures, and specifically discloses a high-tensile-strength EPDM elastic pad rubber mixture and a preparation method thereof. The EPDM elastic pad rubber mixture disclosed by the application specifically comprises the following components: raw rubber 80-120 parts, reinforcing agent 70-100 parts, paraffin oil 20-30 parts, zinc oxide 4-7 parts, stearic acid 1-3 parts, anti-aging agent 2-6 parts, sulfur 0.5-1 part, accelerator 1-3 parts, and dithio-bicyclohexylamide 2-3 parts; the reinforcing agent is obtained by mixing N550 fast-pressing carbon black, N330 high-wear-resistance carbon black and maleic anhydride-acrylate modified lignin; the anti-aging agent is composed of anti-aging agent RD and anti-aging agent 4010NA; and the accelerator is composed of thiuram accelerator and thiazole accelerator. The raw material formula is improved, the prepared rubber mixture has excellent tensile strength, and the rubber mixture has excellent hot air aging resistance and fatigue resistance.

Description

Technical Field

[0001] This application relates to the technical field of rubber compound, specifically to a high tensile strength EPDM elastic pad compound and its preparation method. Background Technology

[0002] Currently, high-speed rail is developing rapidly, with speeds constantly breaking records, such as the CR450 EMU prototype reaching a speed of 450 kilometers per hour. Behind this continuous increase in speed, the impact and vibration loads on the railway track system are also increasing exponentially, which places extremely high demands on the performance of track components. As a key safety component ensuring track stability, the improvement of the tensile strength of the elastic pad layer is of great significance.

[0003] The elastic padding layer in railway tracks is a key component ensuring the safe and stable operation of high-speed railways, primarily used in the limiting groove devices of track slabs. It absorbs the impact force generated by high-speed trains, restricts track slab displacement, and ensures track structural stability. According to the "Elastic Padding Layer for Limiting Structure of Double-Block Ballastless Track on Bridges" (Q / CR6-2014), the raw material for the elastic padding layer must be EPDM rubber with a tensile strength ≥12MPa and an elongation at break ≥250%. Low tensile strength of the elastic padding layer can have many serious consequences. Insufficient strength means it cannot effectively absorb the impact energy of train operation, leading to reduced track stability, increased train vibration, decreased comfort, and even potential deviation from the normal operating trajectory. Furthermore, this will subject the track system to greater pressure and impact, accelerating the wear of track slabs, fasteners, and other components, shortening the service life of track infrastructure, and increasing maintenance costs and frequency. In extreme cases, low tensile strength of the elastic padding layer may lead to premature failure and fracture, posing a significant safety risk to high-speed trains and potentially causing major accidents.

[0004] Therefore, improving the tensile strength of the elastic pad is a key measure to adapt to the increase in railway speed, ensure operational safety, and promote the sustainable development of railways. Summary of the Invention

[0005] To address the aforementioned technical problems, this application provides a high tensile strength EPDM elastic pad compound and its preparation method.

[0006] This application provides a high tensile strength EPDM elastic cushioning compound, specifically comprising the following components in parts by weight: 80-120 parts raw rubber, 70-100 parts reinforcing agent, 20-30 parts paraffin oil, 4-7 parts zinc oxide, 1-3 parts stearic acid, 2-6 parts antioxidant, 0.5-1 part sulfur, 1-3 parts accelerator, and 2-3 parts dicaprolactam disulfide; The raw rubber is composed of a mixture of high-ethylene medium Mooney EPDM3092, low-ethylene high Mooney EPDM8550, and low-ethylene low Mooney EPDM501A in a weight ratio of 1-2:2-3:1-2. The reinforcing agent is obtained by mixing N550 fast-extruded carbon black, N330 high-abrasion-resistant carbon black, and maleic anhydride-acrylate modified lignin in a weight ratio of 5-7:2-3:0.5-2. The antioxidant is composed of antioxidant RD and antioxidant 4010NA mixed in a weight ratio of 1-3:1-3; The accelerator is composed of a mixture of thiuram-based accelerators and thiazole-based accelerators in a weight ratio of 0.5-1.5:0.5-1.5.

[0007] The core requirements of the EPDM elastic cushioning compound produced in this application are high elasticity, ease of production, and low cost. By precisely designing the raw rubber, reinforcing materials, anti-aging system materials, and low-sulfur, high-accelerator sulfur vulcanization system, the prepared compound has excellent tensile strength, and the compound has excellent resistance to hot air aging and fatigue resistance.

[0008] This application uses a combination of medium-ethylene high Mooney EPDM, low-ethylene low Mooney EPDM, high-ethylene medium Mooney EPDM 3092, low-ethylene high Mooney EPDM 8550, and low-ethylene low Mooney EPDM 501A for raw rubber. The high cohesive strength of the former enhances the tensile strength of the vulcanized rubber, while the low Mooney viscosity of the latter improves processing fluidity, and the low ethylene content enhances molecular chain flexibility to optimize elasticity and compression set. By adjusting the ratio of the three components, a synergistic balance of tensile strength, processability, and elastic compression set is achieved, meeting the comprehensive requirements of EPDM elastic pads for 'high strength + easy processing + excellent elasticity'.

[0009] The reinforcing filler system of this application employs a combination of N550 fast-extruded carbon black, N330 high-abrasion-resistant carbon black, and maleic anhydride-acrylate modified lignin. N330, with its small particle size and high structural properties, strengthens the tensile strength and abrasion resistance of the vulcanizate. N550 optimizes the processing flowability and dispersion uniformity of the rubber compound through its easy dispersibility. Maleic anhydride-acrylate modified lignin possesses multiple active reaction sites, resulting in better compatibility and entanglement with rubber molecules. The covalent bond between the modified lignin and rubber enhances interfacial interaction, reducing defects caused by poor filler-rubber interfacial bonding after thermal aging, and maintaining the structural integrity of the material. Simultaneously, it better buffers and disperses stress, reducing stress concentration around carbon black particles. The synergistic effect of these three components ensures the core performance of the EPDM elastic pad—"high strength and high abrasion resistance"—while also maintaining good aging resistance and processability, achieving a balance between performance and production.

[0010] This application selects a composite antioxidant combining "fatigue resistance and thermo-oxidative resistance": The elastic padding layer is subjected to long-term dynamic compression, which easily leads to a decrease in tensile strength due to fatigue aging. Therefore, antioxidants RD and 4010NA are selected as a composite. 4010NA can delay the breakage of cross-linking bonds under dynamic fatigue; RD can inhibit the damage to the rubber molecular chains caused by thermo-oxidative aging, avoiding a precipitous drop in strength after long-term use.

[0011] This application selects a low-sulfur, high-accelerator sulfur vulcanization system. The core principle of this system is to construct a strong and tough cross-linked network. The mechanical properties of rubber are determined by the type and density of cross-linked bonds formed after vulcanization. Polysulfide bonds (-S-, n≥3) have lower bond energy but longer bond lengths and better flexibility; under stress, they can absorb energy through bond stretching and partial fracture, giving rubber excellent elasticity and fatigue resistance. Low-sulfur bonds (monosulfide bonds -S-, disulfide bonds -SS-) have high bond energy but short bond lengths and high rigidity; although they can improve strength, they can lead to brittleness and decreased elasticity in rubber. Therefore, by adjusting the appropriate formulation ratio, suitable types and concentrations of accelerators can be obtained to preferentially generate polysulfide cross-linked bonds under low-sulfur conditions, while maintaining a "moderately high" cross-linking density. This avoids both the poor strength caused by insufficient cross-linking and the loss of elasticity caused by excessive cross-linking.

[0012] Preferably, the high tensile strength EPDM elastic cushion compound specifically comprises the following components in parts by weight: 90-110 parts raw rubber, 80-90 parts reinforcing agent, 22-28 parts paraffin oil, 5-6 parts zinc oxide, 1.5-2.5 parts stearic acid, 3-5 parts antioxidant, 0.6-0.9 parts sulfur, 1.5-2.5 parts accelerator, and 2.2-2.8 parts dicaprolactam disulfide.

[0013] Preferably, the raw rubber is composed of a mixture of high-ethylene medium Mooney EPDM3092, low-ethylene high Mooney EPDM8550, and low-ethylene low Mooney EPDM501A in a weight ratio of 1.3-1.7:2.3-2.7:1.3-1.7.

[0014] In one specific implementation, the weight ratio of high-ethylene medium Mooney EPDM3092, low-ethylene high Mooney EPDM8550, and low-ethylene low Mooney EPDM501A in the raw rubber can be 1:2:1, 1.3:2:1, 1.5:2:1, 1.7:2:1, 2:2:1, 1:2.3:1, 1.3:2.3:1, 1.5:2.5:1, 1.7:2.7:1, 2:3:1, 1:3:1.3, 1.3:2:1.5, 1.5:2:1.7, or 1.7:2:2.

[0015] Experimental analysis shows that selecting the above-mentioned weight ratios of high-ethylene medium Mooney EPDM3092, low-ethylene high Mooney EPDM8550, and low-ethylene low Mooney EPDM501A as raw rubber can further improve the performance of the compounded rubber.

[0016] Preferably, the reinforcing agent is obtained by mixing N550 fast-extruded carbon black, N330 high-abrasion-resistant carbon black, and maleic anhydride-acrylate modified lignin in a weight ratio of 5.5-6.5:2.2-2.8:0.7-1.5.

[0017] In one specific implementation, the weight ratio of N550 fast-extruded carbon black, N330 high-abrasion-resistant carbon black, and maleic anhydride-acrylate modified lignin in the reinforcing agent can be 5:2:0.5, 5.5:2:0.5, 6:2:0.5, 6.5:2:0.5, 7:2:0.5, 5:2.2:0.5, 5.5:2.5:0.5, 6:2.8:0.5, 6.5:3:0.5, 5:2.2:0.7, 5.5:2.5:1, 6:2.8:1.5, or 6.5:3:2.

[0018] Experimental analysis shows that the reinforcing agent prepared by selecting the above-mentioned weight ratio of N550 fast-extrusion carbon black, N330 high-abrasion-resistant carbon black, and maleic anhydride-acrylate modified lignin can further improve the performance of the compound.

[0019] Preferably, the maleic anhydride-acrylate modified lignin is obtained by reacting lignin, maleic anhydride, acrylate, and dicumyl peroxide in a weight ratio of 80-100:5-7:4-6:0.8-1.2 at a temperature of 140-170°C.

[0020] Preferably, the antioxidant is composed of antioxidant RD and antioxidant 4010NA mixed in a weight ratio of 1-1.5:2-3.

[0021] Preferably, the accelerator is composed of a mixture of thiuram-based accelerators and thiazole-based accelerators in a weight ratio of 0.8-1.2:0.8-1.2.

[0022] Preferably, the accelerator is composed of a mixture of thiuram-based accelerator TMTD and thiazole-based accelerator MBTS in a weight ratio of 0.8-1.2:0.8-1.2.

[0023] Secondly, this application also provides a method for preparing the high tensile strength EPDM elastic pad compound, specifically including the following steps in sequence: (1) Add raw rubber, zinc oxide, stearic acid and antioxidant to the internal mixer, and mix for 40-60 seconds under the conditions of temperature of 60-80℃, pressure of 4-6 bar and speed of 35-45 r / min, and then raise the top bolt. Then add reinforcing agent and paraffin oil, heat to 120-150℃, and mix for 100-200s under pressure of 4-6 bar and speed of 25-35 r / min. Discharge the material and raise the top plug 1-2 times in the middle to obtain intermediate rubber compound. (2) Pass the intermediate rubber compound through a thin sheet and then sheet it; cool the rubber compound to room temperature and let it stand for more than 8 hours to obtain the masterbatch; (3) Add the masterbatch to the internal mixer, along with sulfur and accelerator, and mix for 100-150 seconds under a pressure of 8-10 bar and a speed of 20-30 r / min. Discharge the material at ≤90℃; pass through a thin tube and extrude the strip. (4) After cooling to 20-25℃, stand for 16-24 hours to obtain the finished product.

[0024] Thirdly, this application also provides the application of the high tensile strength EPDM elastic pad compound in track components.

[0025] In summary, the technical solution of this application has the following effects: This application achieves excellent tensile strength, as well as superior resistance to hot air aging and fatigue resistance, through precise design of raw rubber, reinforcing materials, anti-aging system materials, and a low-sulfur, high-acceleration sulfur vulcanization system.

[0026] The elastic padding compound provided in this application has enhanced resistance to the propagation of microcracks caused by local stress. Under repeated deformation, the molecular chains have a stronger ability to resist the accumulation of irreversible damage, reducing problems such as elasticity decay and hardness increase caused by fatigue aging, thereby improving the overall service life.

[0027] After the tensile strength of the elastic padding compound provided in this application is effectively improved, the material can withstand higher dynamic impact loads, and its ability to resist instantaneous high stress damage is enhanced. It can be adapted to impact strength at higher speeds and reduce problems such as abnormal track vibration and increased noise caused by padding failure. Detailed Implementation

[0028] The present application will be further described in detail below with reference to embodiments, comparative examples and performance test results. These embodiments should not be construed as limiting the scope of protection claimed in this application.

[0029] In the embodiments of this application, the ethylene content of the high-ethylene medium Mooney EPDM3092PM is 67.2%, and the ethylene content of ML(1+4) at 125°C is 61; the ethylene content of the low-ethylene high Mooney EPDM8550C is 48%, and the ethylene content of ML(1+4) at 125°C is 80; the ethylene content of the low-ethylene low Mooney EPDM501A is 53%, and the ethylene content of ML(1+4) at 125°C is 30.

[0030] Example

[0031] Examples 1-5 Examples 1-5 respectively provide a high tensile strength EPDM elastic pad compound and its preparation method.

[0032] The difference in the above embodiments is that the amount of each raw material component in the high tensile strength EPDM elastic pad compound is different, as shown in Table 1.

[0033] The preparation method of maleic anhydride-acrylate modified lignin in the above embodiments is as follows: 90g of dried lignin, 6g of maleic anhydride, and 5g of acrylate are added to a high-speed mixer according to the specified ratio and mixed at 500r / min for 10min to achieve uniform dispersion. 1g of dicumyl peroxide is added to the mixture, and mixing continues for 5min. The internal mixer is started, preheated to 150℃, and the speed is set to 70r / min. After the temperature stabilizes, all the pretreated mixture is added to the mixing chamber, and the reaction time is 30min. After the reaction is completed, the discharge port of the internal mixer is quickly opened, the product is removed, and it is pressed into thin sheets with a thickness of 2-3mm while still hot, and then allowed to cool naturally to room temperature. The cooled product was pulverized to a particle size ≤2mm, and acetone with a solid-liquid ratio of 1g:15mL was added. The mixture was stirred and refluxed in a 60℃ water bath for 2h to remove ungrafted monomers, initiator residues, and low-molecular-weight byproducts. The refluxed mixture was placed in a centrifuge and centrifuged at 8000r / min for 15min. The precipitate was collected. The "acetone reflux-centrifugation" operation was repeated twice. The precipitate was then placed in a vacuum drying oven and dried at 80℃ for 12h to obtain maleic anhydride-acrylate modified lignin.

[0034] The preparation method of the high tensile strength EPDM elastic pad compound in the above embodiments is as follows: (1) Add medium raw rubber (composed of high ethylene medium Mooney EPDM3092, low ethylene high Mooney EPDM8550 and low ethylene low Mooney EPDM501A in a weight ratio of 1.5:2.5:1.5), zinc oxide, stearic acid and antioxidant (composed of antioxidant RD and antioxidant 4010NA in a weight ratio of 1.5:2) to the internal mixer. Mix for 50 seconds at a temperature of 70℃, a pressure of 5 bar and a speed of 40 r / min, and then raise the top plug. Then add reinforcing agent (obtained by mixing N550 fast-extrusion carbon black, N330 high-abrasion-resistant carbon black, and maleic anhydride-acrylate modified lignin in a weight ratio of 5.5:2.8:0.7) and paraffin oil. Heat to 135℃ and mix for 150 seconds at a pressure of 5 bar and a speed of 30 r / min. Discharge the material and raise the top plug twice in the middle to volatilize some small molecule organic matter, thus obtaining intermediate rubber compound. (2) The intermediate rubber compound is thinly passed through the No. 1 open mill and sheeted out of the No. 2 open mill; the above rubber compound is cooled to room temperature and left to stand for more than 8 hours to obtain the masterbatch; (3) Add the above masterbatch to the internal mixer, along with sulfur and accelerator (composed of 1:1 thiuram accelerator TMTD and thiazole accelerator MBTS by weight ratio), mix for 120s under a pressure of 9 bar and a speed of 25 r / min, and discharge at ≤90℃; pass through a thin mill and produce strips. (4) After cooling to 23°C, let stand for 24 hours to obtain the finished product.

[0035] Table 1. Amounts of each raw material component in Examples 1-5 and Comparative Examples 1-2

[0036] Examples 6-9 Examples 6-9 respectively provide a high tensile strength EPDM elastic pad compound and its preparation method.

[0037] The difference between the above embodiments and Embodiment 1 is that the types of raw rubber are different, as detailed below.

[0038] In Example 6: the raw rubber is composed of a mixture of high-ethylene medium Mooney EPDM3092, low-ethylene high Mooney EPDM8550, and low-ethylene low Mooney EPDM501A in a weight ratio of 1.3:2.7:1.7.

[0039] In Example 7: the raw rubber is composed of a mixture of high-ethylene medium Mooney EPDM3092, low-ethylene high Mooney EPDM8550, and low-ethylene low Mooney EPDM501A in a weight ratio of 1.7:2.3:1.3.

[0040] In Example 8: the raw rubber is composed of a mixture of high-ethylene medium Mooney EPDM3092, low-ethylene high Mooney EPDM8550, and low-ethylene low Mooney EPDM501A in a weight ratio of 1:3:2.

[0041] In Example 9: the raw rubber is composed of a mixture of high-ethylene medium Mooney EPDM3092, low-ethylene high Mooney EPDM8550, and low-ethylene low Mooney EPDM501A in a weight ratio of 2:3:1.

[0042] All other process parameters in the above embodiments are the same as those in Embodiment 1.

[0043] Examples 10-13 Examples 10-13 respectively provide a high tensile strength EPDM elastic pad compound and its preparation method.

[0044] The difference between the above embodiments and Embodiment 1 is that the type of reinforcing agent is different, as shown below.

[0045] In Example 10: The reinforcing agent was obtained by mixing N550 fast-extruded carbon black, N330 high-abrasion-resistant carbon black, and maleic anhydride-acrylate modified lignin in a weight ratio of 6.5:2.2:1.5.

[0046] In Example 11: The reinforcing agent was obtained by mixing N550 fast extruded carbon black, N330 high abrasion-resistant carbon black and maleic anhydride-acrylate modified lignin in a weight ratio of 7:2:2.

[0047] In Example 12: In the reinforcing agent, the weight ratio of lignin, maleic anhydride, acrylate and dicumyl peroxide in the raw materials for preparing maleic anhydride-acrylate modified lignin is 80:7:4:0.8.

[0048] In Example 13: In the reinforcing agent, the weight ratio of lignin, maleic anhydride, acrylate and dicumyl peroxide in the raw materials for preparing maleic anhydride-acrylate modified lignin is 100:5:6:1.2.

[0049] All other process parameters in the above embodiments are the same as those in Embodiment 1.

[0050] Comparative Example Comparative Examples 1-2 Comparative Examples 1 and 2 respectively provide an EPDM elastic padding compound and its preparation method.

[0051] The difference between the above comparative example and Example 1 is that the amount of each component in the EPDM elastic pad compound is different, as shown in Table 1.

[0052] All other process parameters in the above comparative examples are the same as those in Example 1.

[0053] Comparative Examples 3-5 Comparative Examples 3-5 each provide an EPDM elastic padding compound and its preparation method.

[0054] The difference between the above comparative example and Example 1 is as follows.

[0055] In Comparative Example 3, the raw rubber was composed of a mixture of high-ethylene medium Mooney EPDM3092, low-ethylene high Mooney EPDM8550, and low-ethylene low Mooney EPDM501A in a weight ratio of 2.7:1.3:1.3.

[0056] In Comparative Example 4, the reinforcing agent was obtained by mixing N550 fast-extruded carbon black, N330 high-abrasion-resistant carbon black, and lignin (unmodified) in a weight ratio of 5.5:2.8:0.7.

[0057] In Comparative Example 5: The reinforcing agent was obtained by mixing N550 fast extruded carbon black, N330 high abrasion-resistant carbon black, and maleic anhydride-acrylate modified lignin in a weight ratio of 2.8:5.5:0.7.

[0058] All other process parameters in the above comparative examples are the same as those in Example 1.

[0059] Performance testing (1) Tensile strength: The tensile strength of the compound rubber sample shall be determined in accordance with the provisions of GB / T 528.

[0060] (2) Resistance to hot air aging: According to GB / T 3512-2014 "Accelerated aging and heat resistance test of vulcanized rubber or thermoplastic rubber in hot air", the change in tensile strength of the compound sample before and after aging was measured to evaluate the resistance to hot air aging of the compound. The test conditions were 100℃×70h and 125℃×70h. Tensile strength change rate = (tensile strength of aged sample - tensile strength of original sample) / tensile strength of original sample × 100%.

[0061] (3) Dynamic fatigue: The presence of penetrating cracks in the compound was detected by simulating the plugging and unplugging test of the on-board charging gun (bending radius 3D×100,000 cycles, environment from -40℃ to 125℃).

[0062] Test results are shown in Table 2.

[0063] Table 2 Performance test results of the compound rubber in the examples and comparative examples

[0064] As can be seen from the test results in Table 2 above, by using the technical solution provided in this application and improving the raw material formulation and process, the prepared compound has excellent tensile strength, and the compound has excellent resistance to hot air aging and fatigue resistance.

[0065] By comparing the test results of Examples 1-5 and Comparative Examples 1-2, it can be seen that the dosage of each raw material component has a significant impact on the performance of the compound. In Comparative Examples 1-2, the dosage of raw materials was mismatched, resulting in compound with poor tensile strength, mechanical properties, and anti-aging properties. In contrast, this application, by precisely matching the dosage of each raw material component, effectively ensures that the compound has excellent mechanical properties and anti-aging properties.

[0066] Comparing the test results of Examples 1, 6-9, and Comparative Example 3, it can be seen that the raw rubber in Comparative Example 3, composed of a mixture of high-ethylene medium Mooney EPDM3092, low-ethylene high Mooney EPDM8550, and low-ethylene low Mooney EPDM501A in a weight ratio of 2.7:1.3, exhibits poor tensile strength, mechanical properties, and anti-aging properties. In contrast, the raw rubber prepared in this application, composed of a mixture of high-ethylene medium Mooney EPDM3092, low-ethylene high Mooney EPDM8550, and low-ethylene low Mooney EPDM501A in a weight ratio of 1-2:2-3:1-2, produces a compound with excellent mechanical properties and anti-aging properties.

[0067] Comparing the test results of Examples 1, 10-13, and Comparative Examples 4-5, it can be seen that the reinforcing agent in Comparative Example 3 was obtained by mixing N550 fast-extruded carbon black, N330 high-abrasion-resistant carbon black, and unmodified lignin in a weight ratio of 5.5:2.8:0.7. In Comparative Example 4, the reinforcing agent was obtained by mixing N550 fast-extruded carbon black, N330 high-abrasion-resistant carbon black, and maleic anhydride-acrylate modified lignin in a weight ratio of 2.8:5.5:0.7. The resulting compound exhibited poor tensile strength, mechanical properties, and anti-aging properties. In contrast, the present application, by mixing N550 fast-extruded carbon black, N330 high-abrasion-resistant carbon black, and maleic anhydride-acrylate modified lignin in a weight ratio of 5-7:2-3:0.5-2 to obtain the reinforcing agent, produces a compound with excellent mechanical properties and anti-aging properties.

[0068] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention are within the scope of protection claimed by the present invention.

Claims

1. A high tensile strength EPDM elastic pad compound, characterized in that, Specifically, it includes the following components in parts by weight: 80-120 parts raw rubber, 70-100 parts reinforcing agent, 20-30 parts paraffin oil, 4-7 parts zinc oxide, 1-3 parts stearic acid, 2-6 parts antioxidant, 0.5-1 part sulfur, 1-3 parts accelerator, and 2-3 parts dicaprolactam disulfide. The raw rubber is composed of a mixture of high-ethylene medium Mooney EPDM3092, low-ethylene high Mooney EPDM8550, and low-ethylene low Mooney EPDM501A in a weight ratio of 1-2:2-3:1-2. The reinforcing agent is obtained by mixing N550 fast-extruded carbon black, N330 high-abrasion-resistant carbon black, and maleic anhydride-acrylate modified lignin in a weight ratio of 5-7:2-3:0.5-2. The antioxidant is composed of antioxidant RD and antioxidant 4010NA mixed in a weight ratio of 1-3:1-3; The accelerator is composed of a mixture of thiuram-based accelerators and thiazole-based accelerators in a weight ratio of 0.5-1.5:0.5-1.

5. The maleic anhydride-acrylate modified lignin is obtained by reacting lignin, maleic anhydride, acrylate, and dicumyl peroxide in a weight ratio of 80-100:5-7:4-6:0.8-1.2 at a temperature of 140-170℃.

2. The high tensile strength EPDM elastic pad compound according to claim 1, characterized in that, Specifically, it includes the following components in parts by weight: 90-110 parts raw rubber, 80-90 parts reinforcing agent, 22-28 parts paraffin oil, 5-6 parts zinc oxide, 1.5-2.5 parts stearic acid, 3-5 parts antioxidant, 0.6-0.9 parts sulfur, 1.5-2.5 parts accelerator, and 2.2-2.8 parts dicaprolactam disulfide.

3. The high tensile strength EPDM elastic pad compound according to claim 1, characterized in that, The raw rubber is composed of a mixture of high-ethylene medium Mooney EPDM3092, low-ethylene high Mooney EPDM8550, and low-ethylene low Mooney EPDM501A in a weight ratio of 1.3-1.7:2.3-2.7:1.3-1.

7.

4. The high tensile strength EPDM elastic pad compound according to claim 1, characterized in that, The reinforcing agent is obtained by mixing N550 fast-extrusion carbon black, N330 high-abrasion-resistant carbon black, and maleic anhydride-acrylate modified lignin in a weight ratio of 5.5-6.5:2.2-2.8:0.7-1.

5.

5. The high tensile strength EPDM elastic pad compound according to claim 1, characterized in that, The antioxidant is composed of antioxidant RD and antioxidant 4010NA mixed in a weight ratio of 1-1.5:2-3.

6. The high tensile strength EPDM elastic pad compound according to claim 1, characterized in that, The accelerator is composed of a mixture of thiuram-based accelerators and thiazole-based accelerators in a weight ratio of 0.8-1.2:0.8-1.

2.

7. The high tensile strength EPDM elastic pad compound according to claim 1, characterized in that, The accelerator is composed of a mixture of thiuram-based accelerator TMTD and thiazole-based accelerator MBTS in a weight ratio of 0.8-1.2:0.8-1.

2.

8. The method for preparing the high tensile strength EPDM elastic pad compound according to any one of claims 1-7, characterized in that, Specifically, the following steps are performed sequentially: (1) Add raw rubber, zinc oxide, stearic acid and antioxidant to the internal mixer, and mix for 40-60 seconds under the conditions of temperature of 60-80℃, pressure of 4-6 bar and speed of 35-45 r / min, and then raise the top bolt. Then add reinforcing agent and paraffin oil, heat to 120-150℃, and mix for 100-200s under pressure of 4-6 bar and speed of 25-35 r / min. Discharge the material and raise the top plug 1-2 times in the middle to obtain intermediate rubber compound. (2) Pass the intermediate rubber compound through a thin sheet and then sheet it; cool the rubber compound to room temperature and let it stand for more than 8 hours to obtain the masterbatch; (3) Add the masterbatch to the internal mixer, along with sulfur and accelerator, and mix for 100-150 seconds under a pressure of 8-10 bar and a speed of 20-30 r / min. Discharge the material at ≤90℃; pass through a thin tube and extrude the strip. (4) After cooling to 20-25℃, stand for 16-24 hours to obtain the finished product.

9. The application of the high tensile strength EPDM elastic pad compound as described in any one of claims 1-7 in track components.

Images