A high and low temperature resistant EPDM rubber compound and its preparation method

Abstract

The present application relates to the field of EPDM rubber, and specifically discloses a high- and low-temperature resistant EPDM rubber mix and its preparation method. A high- and low-temperature resistant EPDM rubber mix, calculated by weight, comprises the following raw materials: 100 parts of EPDM rubber; 20-25 parts of compounded eucommia gum; 40-45 parts of carbon black; 20-25 parts of white carbon black; 5-10 parts of paraffin oil; 2-3 parts of zinc oxide; 1-2 parts of stearic acid; 1.5-2.5 parts of peroxide; 2-2.5 parts of a cross-linking aid; 2-3 parts of an antioxidant; 1 part of sulfur; and 2-3 parts of an accelerator. The EPDM rubber mix of the present application can still maintain good resilience and mechanical properties at -20°C and below, and the mass change rate after heat treatment at 150°C for 96 hours does not exceed 1.4wt%, ensuring stable performance in high-temperature environments. The low-temperature characteristic T10 rigidity modulus of the EPDM rubber mix reaches -50°C or even lower, and has a wide range of applications.

Description

Technical Field

[0001] The present application relates to the technical field of EPDM rubber, and in particular to an EPDM rubber compound that is resistant to high and low temperatures and a preparation method thereof. Background Art

[0002] Rubber materials have always played a vital role in the industrial materials sector. With the continuous advancement of technology and the increasing demands for material performance across various industries, rubber materials are undergoing continuous development and innovation. EPDM rubber, a type of rubber material, has attracted significant attention for its unique performance advantages. It is produced by uniformly mixing EPDM rubber with reinforcing fillers and other additives through either internal or open mixing processes. EPDM raw rubber is a blend of ethylene, propylene, and a third monomer. The ethylene segments impart excellent heat resistance and rigidity, while the propylene segments, through their methyl side chains, disrupt the regularity of the ethylene segments, enhancing overall flexibility and low-temperature resistance. A balanced combination of these two monomers delivers balanced heat resistance and appropriate rigidity and toughness. The third monomer regulates vulcanization activity. This rubber compound, with its advantages such as aging resistance, excellent mechanical properties, balanced high and low temperature resistance, and flexible processing, plays a vital role in various industrial sectors. It is particularly valuable in seals, shock absorbers, and waterproof membranes, driving the development and progress of these industries.

[0003] In the past, the industry has adopted a variety of conventional methods to address the issue of improving the performance of EPDM rubber compounds. In order to improve the overall performance of the rubber compound, it is usually necessary to start by adjusting the ratio of raw materials. For example, the ratio of ethylene and propylene in EPDM rubber is changed in the hope of optimizing the high and low temperature resistance of the rubber compound. At the same time, it is also common to select suitable reinforcing fillers and other additives, such as using different types of carbon black, white carbon black, etc., to enhance the mechanical properties of the rubber compound. In addition, the various raw materials are mixed more evenly by adjusting the internal or open mixing process parameters, such as temperature and time, to improve the quality and performance of the rubber compound. However, although these methods can improve certain properties of the rubber compound to a certain extent, they still have significant limitations when faced with increasingly complex and harsh usage environments.

[0004] With the continuous development of human society's production and living needs, conventional EPDM rubber compounds are facing more severe tests. In low-temperature environments, such as -20°C and below, the material's resilience will be severely reduced, and its mechanical properties will be partially lost, making it difficult to meet the requirements of long-term use in large temperature differences and low-temperature environments. Some researchers have tried to use EPDM raw rubber with a lower ethylene content and a higher propylene content to improve low-temperature resistance, but this will lead to a significant reduction in heat resistance. Therefore, how to further optimize the low-temperature rigidity of EPDM rubber compounds while maintaining balanced high and low temperature resistance has become a difficult problem that needs to be solved urgently in existing technologies. Summary of the Invention

[0005] In order to solve the above technical problems, the present application provides an EPDM rubber compound that is resistant to high and low temperatures and a preparation method thereof.

[0006] The present application provides a high and low temperature resistant EPDM rubber compound, which includes the following raw materials, calculated by weight: 100 parts of EPDM rubber; 20-25 parts of compounded eucommia gum; 40-45 parts of carbon black; 20-25 parts of white carbon black; 5-10 parts of paraffin oil; 2-3 parts of zinc oxide; 1-2 parts of stearic acid; 1.5-2.5 parts of peroxide; 2-2.5 parts of a cross-linking aid; 2-3 parts of an antioxidant; 1 part of sulfur; and 2-3 parts of an accelerator.

[0007] By adopting the above technical solution, the present application selects EPDM rubber with an ethylene content of 55wt% and a third monomer (ethylidene norbornene) content of 2.3wt%, which has good low-temperature resistance. A certain ratio of carbon black and white carbon black can be fully dispersed in the system and provide good high-temperature and low-temperature resistance. The eucommia gum matrix in the compounded eucommia gum has the duality and plasticity of rubber, and its glass transition temperature is not higher than -60°C. It has very good low-temperature rigidity and can maintain sufficient toughness and structural stability when used in low-temperature environments. Adding it to the EPDM compound rubber in a certain proportion can fully improve the low-temperature resistance of the EPDM compound rubber. Zinc oxide and stearic acid will generate zinc stearate during the preparation process, which plays a role in improving the activity of sulfur and peroxide. As a result, the degree of vulcanization in the system is more sufficient, the unreacted stearic acid can reduce the viscosity of the rubber, improve the mixing efficiency, and play an anti-scorching role, and the unreacted zinc oxide will generate electrostatic interaction with the carbon black, promoting the further full dispersion of the carbon black in the system. Combined with other additives, this application significantly optimizes the low-temperature rigidity of the EPDM rubber compound while maintaining balanced high and low temperature resistance, ensuring that the material can still maintain good resilience and mechanical properties at -20°C and below, and the mass change rate after heat treatment at 150°C for 96h does not exceed 1.4wt%, ensuring stable performance in high temperature environment, and making the low-temperature characteristic T10 rigidity modulus of the rubber compound reach -50°C or even lower, greatly broadening the application range of the material, especially improving the reliability in low temperature environment. The cross-linking auxiliary agent in this application is triallyl isocyanurate, and the antioxidant is antioxidant RD and antioxidant MB with a weight ratio of 1:1.

[0008] Preferably, the compound eucommia gum includes disulfide heterocycle-modified epoxidized eucommia gum, FeCl3 and epoxidized eucommia gum.

[0009] Preferably, the weight ratio of the disulfide heterocycle-modified epoxidized eucommia gum, FeCl 3 and epoxidized eucommia gum is (40-50): (1.5-2): (50-60).

[0010] By adopting the above technical solution, the present application adds disulfide heterocycle-modified epoxidized eucommia gum, which has good compatibility with EPDM rubber and has high molecular chain flexibility, and can maintain good resilience when used at temperatures of -20°C and below; FeCl3 and epoxidized eucommia gum will form a material with metal coordination bonds during mixing, which also has the property of being fully compatible with EPDM rubber, and the metal coordination bonds therein will play a stabilizing structural effect when the temperature of the mixed rubber changes or is subjected to certain external forces, thereby widening the suitable temperature range of the mixed rubber and improving its mechanical strength to a certain extent; epoxidized eucommia gum can also fully improve the dispersion effect of white carbon black in the rubber matrix.

[0011] Preferably, the weight ratio of the disulfide heterocycle-modified epoxidized eucommia gum, FeCl 3 and epoxidized eucommia gum is (40-50):1.8:55.

[0012] By adopting the above technical solution, the present application strictly controls the weight ratio of disulfide heterocycle modified epoxidized eucommia gum, FeCl3 and epoxidized eucommia gum, so that the improvement effect of the compounded eucommia gum on the various properties of the mixed rubber is optimized to the greatest extent.

[0013] Preferably, the epoxidized eucommia gum is prepared by the following method: dispersing eucommia gum, formic acid and hydrogen peroxide in an organic solvent at a molar ratio of 1: (0.35-0.45): (0.3-0.4), stirring for reaction, adding ethanol for precipitation after reaction, washing and drying to obtain epoxidized eucommia gum.

[0014] Preferably, the disulfide heterocycle-modified epoxidized eucommia gum is prepared by the following method: eucommia gum, formic acid and hydrogen peroxide are dispersed in an organic solvent at a molar ratio of 1: (0.35-0.45): (0.3-0.4), stirred for reaction, and after completion, ethanol is added for precipitation, washed, and dried to obtain epoxidized eucommia gum, which is then dispersed in an organic solvent with thioctic acid at a weight ratio of 1: (0.35-0.4) under inert gas protection, stirred until completely dissolved, and concentrated sulfuric acid is added dropwise. After reacting for 3-4 hours, the product is precipitated with alcohol and dried to obtain disulfide heterocycle-modified epoxidized eucommia gum.

[0015] Preferably, the accelerator comprises accelerator DM and accelerator NS in a weight ratio of 1:1.

[0016] Preferably, the peroxide is 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane.

[0017] In the second aspect, the present application provides a method for preparing a high and low temperature resistant EPDM rubber compound, comprising the following steps: mixing the EPDM rubber, zinc oxide, stearic acid, antioxidant, compound eucommia gum, carbon black, white carbon black and paraffin oil at a temperature of 90-110°C, then adding peroxide and cross-linking aid, mixing evenly, cooling to 40-45°C and adding sulfur and accelerator to continue mixing, mixing evenly, standing overnight, and then vulcanizing at a temperature of 160-170°C and a pressure of 14-15MPa, standing overnight after vulcanization to obtain an EPDM rubber compound.

[0018] Preferably, the compounded eucommia gum includes disulfide heterocycle-modified epoxidized eucommia gum, FeCl3 and epoxidized eucommia gum, and is distributed and added into the system for mixing. Specifically, before the first mixing, 8-10wt% of the epoxidized eucommia gum is evenly blended with white carbon black, and then mixed with the remaining epoxidized eucommia gum, FeCl3, EPDM rubber, zinc oxide, stearic acid, antioxidant, disulfide heterocycle-modified epoxidized eucommia gum, carbon black and paraffin oil at a temperature of 90-110°C.

[0019] By adopting the above technical solution, the present application evenly blends a certain proportion of epoxidized eucommia gum and silica before the first mixing. The two can interact with each other via the active groups on their surfaces, and the epoxidized eucommia gum has a good compatibility effect with EPDM rubber. Therefore, in the subsequent mixing process, silica can be more evenly dispersed inside the rubber matrix.

[0020] In summary, this application has the following beneficial technical effects:

[0021] 1. While maintaining balanced high and low temperature resistance, this application significantly optimizes the low-temperature rigidity of the EPDM rubber compound, ensuring that the material maintains good resilience and mechanical properties at -20°C and below. The mass change rate after heat treatment at 150°C for 96 hours does not exceed 1.4wt%, ensuring stable performance in high-temperature environments. The low-temperature characteristic T10 rigidity modulus of the rubber compound reaches -50°C or even lower, greatly broadening the application range of the material and, in particular, improving its reliability in low-temperature environments.

[0022] 2. In the preparation method of the present application, when disulfide heterocycle-modified epoxidized eucommia gum, FeCl3 and epoxidized eucommia gum are added, a certain proportion of epoxidized eucommia gum and silica are evenly blended before the first mixing. The two can interact with each other via the active groups on their surfaces, and the epoxidized eucommia gum has a good compatibility effect with EPDM rubber. Therefore, in the subsequent mixing process, silica can be more evenly dispersed inside the rubber matrix. DETAILED DESCRIPTION

[0023] Material Source

[0024] Unless otherwise specified, the raw materials used in this application are all commercially available products, specifically:

[0025] Eucommia gum, industrial grade, was purchased from Shandong Beilong Eucommia Bioengineering Co., Ltd.;

[0026] EPDM rubber was purchased from Mitsui Chemicals, with the brand name 2060M, ethylene 55wt%, ethylidene norbornene 2.3wt%, and Mooney viscosity =40;

[0027] Carbon black was purchased from Ningbo Detai Chemical Co., Ltd. with the brand name N550;

[0028] Silica was purchased from Rhodia Silica (Qingdao) Co., Ltd. with the brand name Z1165MP.

[0029] The present application is further described in detail below with reference to preparation examples, embodiments and comparative examples.

[0030] Preparation Example 1.1

[0031] The preparation method of epoxidized eucommia gum comprises the following steps:

[0032] Eucommia gum is dispersed in cyclohexane to form a solution with a concentration of 8wt%, and stirred at 50°C until completely dissolved. After keeping the temperature at 40°C for 2h, formic acid is added, and after standing for 10min, hydrogen peroxide is added and the addition is completed dropwise within 10min. After reacting for 3h, sodium bicarbonate is added dropwise to stop the reaction. The product is precipitated with ethanol, washed, and dried in a vacuum oven at 40°C for 48h to obtain epoxidized Eucommia gum, and the molar ratio of Eucommia gum, formic acid and hydrogen peroxide is controlled to be 1:0.35:0.4.

[0033] Preparation Example 1.2

[0034] The preparation method of epoxidized eucommia gum comprises the following steps:

[0035] Eucommia gum is dispersed in cyclohexane to form a solution with a concentration of 8wt%, and stirred at 50°C until completely dissolved. After keeping the temperature at 40°C for 2h, formic acid is added. After standing for 10min, hydrogen peroxide is added and the addition is completed dropwise within 10min. After reacting for 3h, sodium bicarbonate is added dropwise to stop the reaction. The product is precipitated with ethanol, washed, and dried in a vacuum oven at 40°C for 48h to obtain epoxidized Eucommia gum. The molar ratio of Eucommia gum, formic acid and hydrogen peroxide is controlled to be 1:0.45:0.3.

[0036] Preparation Example 2.1

[0037] The preparation method of disulfide heterocycle modified epoxidized eucommia gum comprises the following steps:

[0038] Eucommia gum is dispersed in cyclohexane to form a solution with a concentration of 8wt%, and stirred at a temperature of 50°C until completely dissolved. After keeping warm at a temperature of 40°C for 2h, formic acid is added, and hydrogen peroxide is added after standing for 10min. The addition is controlled to be complete within 10min. After reacting for 3h, sodium bicarbonate is added dropwise to stop the reaction. The product is precipitated with ethanol, washed, and dried in a vacuum oven at 40°C for 48h to obtain epoxidized Eucommia gum, and the molar ratio of Eucommia gum, formic acid and hydrogen peroxide is controlled to be 1:0.35:0.4; 5mol of epoxidized Eucommia gum is dispersed in toluene to obtain a solution with a concentration of 2wt%, and stirred at a temperature of 60°C under nitrogen protection until completely dissolved. Then, 1.75mol of thioctic acid is added and stirred until completely dissolved. Then, 20mL of concentrated sulfuric acid is added and stirred. After reacting for 3h, methanol is added to precipitate the product, washed, and dried in a vacuum oven at 40°C to constant weight to obtain disulfide heterocycle-modified epoxidized Eucommia gum.

[0039] Preparation Example 2.2

[0040] The preparation method of disulfide heterocycle modified epoxidized eucommia gum comprises the following steps:

[0041] Eucommia gum is dispersed in cyclohexane to form a solution with a concentration of 8wt%, and stirred at a temperature of 50°C until completely dissolved. After keeping warm at a temperature of 40°C for 2h, formic acid is added, and hydrogen peroxide is added after standing for 10min, and the addition is controlled to be complete within 10min. After reacting for 3h, sodium bicarbonate is added dropwise to stop the reaction, and the product is precipitated with ethanol, washed, and dried in a vacuum oven at 40°C for 48h to obtain epoxidized Eucommia gum, and the molar ratio of Eucommia gum, formic acid and hydrogen peroxide is controlled to be 1:0.45:0.3; 5mol of epoxidized Eucommia gum is dispersed in toluene to obtain a solution with a concentration of 2wt%, and stirred at a temperature of 60°C under nitrogen protection until completely dissolved, and then 2mol of thioctic acid is added and stirred until completely dissolved, and then 20mL of concentrated sulfuric acid is added and stirred. After reacting for 3h, methanol is added to precipitate the product, washed, and dried in a vacuum oven at 40°C to constant weight to obtain disulfide heterocycle-modified epoxidized Eucommia gum.

[0042] Example 1.1

[0043] A method for preparing a high- and low-temperature resistant EPDM rubber compound comprises the following steps (the amounts of each substance are shown in Table 1):

[0044] S1. Place EPDM rubber, carbon black and white carbon black in a drying oven at 80°C for 12 hours to remove moisture and set aside;

[0045] S2. Take out 8wt% of the epoxidized eucommia gum prepared in Preparation Example 1.1, blend it with the dried white carbon black in step S1, and stir for 20 minutes to obtain a mixture. Then, mix it with the remaining epoxidized eucommia gum, FeCl3, EPDM rubber, zinc oxide, stearic acid, antioxidant (antioxidant RD and antioxidant MB in a weight ratio of 1:1) and disulfide heterocycle-modified epoxidized eucommia gum, carbon black and paraffin oil prepared in Preparation Example 2.1 at a temperature of 90°C and a speed of 30 r / min for 5 minutes, add peroxide (1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane) and a crosslinking aid (triallyl isocyanurate), maintain the original temperature and speed and continue mixing for 4 minutes, then increase the speed to 45 r / min, mix for 5 minutes, discharge the glue, put it into an open mill, and mix for 2 minutes at a roller temperature of 45°C to obtain a mixture to be vulcanized;

[0046] S3. Add sulfur and accelerator (accelerator DM and accelerator NS in a weight ratio of 1:1) to the mixture to be vulcanized and continue mixing for 5 minutes. Remove the sheet and let it stand overnight. Then, vulcanize it at a temperature of 170°C, a pressure of 14 MPa, and a time equal to the positive vulcanization time. After the vulcanization is completed, let it stand overnight to obtain an EPDM rubber compound.

[0047] Example 1.2

[0048] A method for preparing a high- and low-temperature resistant EPDM rubber compound comprises the following steps (the amounts of each substance are shown in Table 1):

[0049] S1. Place EPDM rubber, carbon black and white carbon black in a drying oven at 80°C for 12 hours to remove moisture and set aside;

[0050] S2. Take out 10 wt % of the epoxidized eucommia gum prepared in Preparation Example 1.2, blend it with the dried white carbon black in step S1, and stir for 20 min to obtain a mixture. Then, mix it with the remaining epoxidized eucommia gum, FeCl3, EPDM rubber, zinc oxide, stearic acid, antioxidant (antioxidant RD and antioxidant MB in a weight ratio of 1:1) and disulfide heterocycle-modified epoxidized eucommia gum, carbon black and paraffin oil prepared in Preparation Example 2.2 at a temperature of 110°C and a speed of 30 r / min for 4 min, add peroxide (1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane) and a crosslinking aid (triallyl isocyanurate), maintain the original temperature and speed and continue mixing for 4 min, then increase the speed to 45 r / min, mix for 5 min, discharge the glue, put it into an open mill, and mix for 2 min at a roller temperature of 40°C to obtain a mixture to be vulcanized;

[0051] S3. Add sulfur and accelerator (accelerator DM and accelerator NS in a weight ratio of 1:1) to the mixture to be vulcanized and continue mixing for 5 minutes. Remove the sheet and let it stand overnight. Then, vulcanize it at a temperature of 160°C, a pressure of 15 MPa, and a time equal to the positive vulcanization time. After the vulcanization is completed, let it stand overnight to obtain an EPDM rubber compound.

[0052] Table 1 Amount of each component used in Examples 1.1-1.2 (kg)

[0053]

[0054] Example 2.1

[0055] A method for preparing a high- and low-temperature resistant EPDM rubber compound, which differs from Example 1.1 in that: the amount of epoxidized eucommia gum prepared in Preparation Example 1.1 is 0.826 kg, the amount of FeCl3 used is 0.038 kg, the amount of disulfide heterocycle-modified epoxidized eucommia gum prepared in Preparation Example 2.1 is 1.136 kg, and the rest are the same as Example 1.1.

[0056] Example 2.2

[0057] A method for preparing a high- and low-temperature resistant EPDM rubber compound, which differs from Example 1.1 in that: the amount of epoxidized eucommia gum prepared in Preparation Example 1.1 is 0.936 kg, the amount of FeCl3 used is 0.034 kg, the amount of disulfide heterocycle-modified epoxidized eucommia gum prepared in Preparation Example 2.1 is 1.03 kg, and the rest are the same as Example 1.1.

[0058] Example 3.1

[0059] A method for preparing a high- and low-temperature resistant EPDM rubber compound, which differs from Example 2.1 in that: in step S3, the weight ratio of accelerator DM to accelerator NS is 2:1, and the rest is the same as Example 1.1.

[0060] Example 3.2

[0061] A method for preparing a high- and low-temperature resistant EPDM rubber compound, which differs from Example 2.1 in that: in step S3, the weight ratio of accelerator DM to accelerator NS is 1:2, and the rest is the same as Example 1.1.

[0062] Example 4.1

[0063] A method for preparing a high- and low-temperature resistant EPDM rubber compound, which differs from Example 2.1 in that: in step S2, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane is replaced with diisopropylbenzene peroxide, and the rest is the same as Example 1.1.

[0064] Example 4.2

[0065] A method for preparing a high- and low-temperature resistant EPDM rubber compound, which differs from Example 2.1 in that: in step S2, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane is replaced with di-tert-butyl peroxide diisopropylbenzene, and the rest is the same as Example 1.1.

[0066] Example 4.3

[0067] A method for preparing a high- and low-temperature resistant EPDM rubber compound, which differs from Example 2.1 in that: in step S2, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane is replaced with 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane; otherwise, the method is the same as Example 1.1.

[0068] Comparative Example 1

[0069] The difference from Example 1.1 is that the compound eucommia gum is removed, and the rest is the same as Example 1.1.

[0070] Comparative Example 2.1

[0071] The difference from Example 1.1 is that the compound eucommia gum is completely replaced by the epoxidized eucommia gum prepared in Preparation Example 1.1, and the rest is the same as Example 1.1.

[0072] Comparative Example 2.2

[0073] The difference from Example 1.1 is that the compound eucommia gum is completely replaced by the disulfide heterocycle-modified epoxidized eucommia gum prepared in Preparation Example 2.1, and the rest is the same as Example 1.1.

[0074] Performance testing

[0075] High temperature resistance test: The materials obtained in the examples and comparative examples were cut into specimens of 75±0.25 mm×25±0.25 mm×2 mm, and their mass change (wt%) at 150±2°C was tested and recorded in Table 2;

[0076] Low temperature resistance test: Referring to the standard ISO 2912, the low temperature property T10 rigidity modulus (°C) of the materials obtained in the examples and comparative examples was tested and recorded in Table 2.

[0077] Table 2 Performance test table

[0078]

[0079] Data Analysis:

[0080] As can be seen from Table 2, the heat treatment mass change rate of the materials of Examples 1.1-1.2 is 1.37-1.39wt%, and the low-temperature characteristic T10 rigidity modulus is -52°C~-50°C, which proves that the present application significantly optimizes the low-temperature rigidity of the EPDM rubber mix while maintaining balanced high and low temperature resistance, ensuring that the material can still maintain good resilience and mechanical properties at -20°C and below. The mass change rate after heat treatment at 150°C for 96h does not exceed 1.4wt%, ensuring stable performance in a high temperature environment, and making the low-temperature characteristic T10 rigidity modulus of the rubber mix reach -50°C or even lower, greatly broadening the application range of the material, especially improving the reliability in a low temperature environment.

[0081] The difference between Example 2.1-2.2 and Example 1.1 is that the present application changes the amount of epoxidized eucommia gum, the amount of FeCl3 and the disulfide heterocycle-modified epoxidized eucommia gum. The results show that the heat treatment quality change rate of Examples 2.1-2.2 decreases, and the low-temperature characteristic T10 rigid modulus also decreases significantly, proving that the present application strictly controls the weight ratio of disulfide heterocycle-modified epoxidized eucommia gum, FeCl3 and epoxidized eucommia gum, which can maximize the optimization of the effect of the compounded eucommia gum on improving the various properties of the mixed rubber.

[0082] The difference between Comparative Example 1 and Example 1.1 is that the present application removes the compound eucommia gum, and the results show that the heat treatment mass change rate and the low-temperature characteristic T10 rigid modulus are increased. The difference between Comparative Example 2.1-2.2 and Example 1.1 is that the present application replaces the compound eucommia gum with epoxidized eucommia gum and disulfide heterocycle-modified epoxidized eucommia gum, respectively. The results show that the heat treatment mass change rate of Comparative Example 2.1 is increased, and the low-temperature characteristic T10 rigid modulus of Comparative Example 2.2 is increased, which proves that the disulfide heterocycle-modified epoxidized eucommia gum has good compatibility with EPDM rubber, and It also has high molecular chain flexibility and can maintain good resilience when used at temperatures of -20°C and below; FeCl3 and epoxidized eucommia gum will form a material with metal coordination bonds during mixing, which is also fully compatible with EPDM rubber, and the metal coordination bonds therein will play a stabilizing structural role when the temperature of the mixed rubber changes or is subjected to certain external forces, thereby widening the suitable temperature range of the mixed rubber and improving its mechanical strength to a certain extent; epoxidized eucommia gum can also fully improve the dispersion effect of white carbon black in the rubber matrix.

[0083] The embodiments of this specific implementation method are all preferred embodiments of the present application and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A high and low temperature resistant EPDM rubber compound, characterized in that: The raw materials used include the following components by weight: 100 parts of EPDM rubber; 20-25 parts of compounded eucommia gum; 40-45 parts of carbon black; 20-25 parts of white carbon black; 5-10 parts of paraffin oil; 2-3 parts of zinc oxide; 1-2 parts of stearic acid; 1.5-2.5 parts of peroxide; 2-2.5 parts of a crosslinking aid; 2-3 parts of an antioxidant; 1 part of sulfur; 2-3 parts of an accelerator; the composite eucommia gum comprises disulfide heterocycle-modified epoxidized eucommia gum, FeCl3, and epoxidized eucommia gum in a weight ratio of (40-50):1.8:55; the disulfide heterocycle-modified epoxidized eucommia gum is prepared by the following method: eucommia gum, formic acid, and hydrogen peroxide are mixed in a ratio of 1:( The epoxidized eucommia gum is dispersed in an organic solvent at a molar ratio of 1:(0.35-0.45) and (0.3-0.4), stirred for reaction, and ethanol is added after reaction to precipitate, washed, and dried to obtain epoxidized eucommia gum. Subsequently, the epoxidized eucommia gum is dispersed in an organic solvent with thioctic acid at a weight ratio of 1:(0.35-0.4) under inert gas protection, stirred until completely dissolved, and concentrated sulfuric acid is added dropwise. After reaction for 3-4 hours, the product is precipitated with alcohol and dried to obtain disulfide heterocycle-modified epoxidized eucommia gum.

2. The high and low temperature resistant EPDM rubber compound according to claim 1, characterized in that: The epoxidized eucommia gum is prepared by the following method: eucommia gum, formic acid and hydrogen peroxide are dispersed in an organic solvent at a molar ratio of 1:(0.35-0.45):(0.3-0.4), stirred for reaction, and ethanol is added for precipitation after reaction, washed and dried to obtain the epoxidized eucommia gum.

3. The high and low temperature resistant EPDM rubber compound according to claim 1, characterized in that: The accelerators include accelerator DM and accelerator NS in a weight ratio of 1:

1.

4. The high and low temperature resistant EPDM rubber compound according to claim 1, characterized in that: The peroxide is 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane.

5. A method for preparing the high and low temperature resistant EPDM rubber compound according to claim 1, characterized in that: The following steps are involved: The EPDM rubber, zinc oxide, stearic acid, antioxidant, compound eucommia gum, carbon black, white carbon black and paraffin oil are mixed at a temperature of 90-110° C., and then peroxide and a cross-linking aid are added and mixed evenly. The mixture is cooled to 40-45° C., sulfur and an accelerator are added and mixed evenly, and the mixture is left to stand overnight. Subsequently, the mixture is vulcanized at a temperature of 160-170° C. and a pressure of 14-15 MPa. After the vulcanization is completed, the mixture is left to stand overnight to obtain an EPDM rubber mixture.

6. The method for preparing a high and low temperature resistant EPDM rubber compound according to claim 5, characterized in that: The compound eucommia gum includes disulfide heterocycle-modified epoxidized eucommia gum, FeCl3 and epoxidized eucommia gum, which are distributed and added into the system for mixing, specifically: Before the first mixing, 8-10 wt% of epoxidized eucommia gum is evenly blended with white carbon black, and then mixed with the remaining epoxidized eucommia gum, FeCl3, EPDM rubber, zinc oxide, stearic acid, antioxidant, disulfide heterocycle-modified epoxidized eucommia gum, carbon black and paraffin oil at a temperature of 90-110°C.

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