A ternary ethylene propylene rubber sealing strip and a preparation method thereof

Abstract

The application relates to the field of sealing strips, in particular to a three-element ethylene-propylene rubber sealing strip and a preparation method thereof, which comprises the following components in parts by weight: three-element ethylene-propylene rubber 150-180 parts, carbon black 60-90 parts, white carbon black 8-12 parts, peroxide vulcanizing agent 3-8 parts, zinc oxide 6-12 parts, magnesium oxide 12-16 parts, paraffin oil 10-18 parts, accelerator 1-3 parts, stearic acid 1-3 parts, antioxidant 1-3 parts, coupling agent 1-3 parts. The application forms a high-density and uniform crosslinking network through the synergistic effect between carbon black and white carbon black activated by the coupling agent and the generation of C-C crosslinking bonds through the free radical reaction of the peroxide vulcanizing agent, so that the tensile strength of the three-element ethylene-propylene rubber sealing strip is effectively improved.

Description

Technical Field

[0001] This application relates to the field of sealing strips, and in particular to a EPDM rubber sealing strip and its preparation method. Background Technology

[0002] Ethylene propylene diene monomer (EPDM) rubber is a copolymer of ethylene, propylene, and a small amount of non-conjugated diene. It is a type of ethylene propylene rubber. Because its main chain is composed of chemically stable saturated hydrocarbons and it only contains unsaturated double bonds in its side chains, it has excellent aging resistance such as ozone resistance, heat resistance, and weather resistance. It can be widely used in automotive parts, waterproof building materials, wire and cable sheaths, heat-resistant hoses, tapes, automotive seals, and other fields.

[0003] Among them, door and window sealing strips are core components for building energy conservation and sealing protection, and their performance directly affects the airtightness, watertightness, sound insulation, and thermal insulation effects of buildings. Ethylene propylene diene monomer (EPDM) rubber, with its excellent weather resistance, ozone resistance, and UV aging resistance, has become the preferred material for door and window sealing strips. However, the tensile strength of existing EPDM rubber is insufficient to meet people's needs, and edge cracking is prone to occur during use. Therefore, there is an urgent need for an EPDM rubber sealing strip with excellent tensile strength. Summary of the Invention

[0004] To improve the tensile strength of EPDM rubber sealing strips, this application provides an EPDM rubber sealing strip and its preparation method.

[0005] Firstly, this application provides a EPDM rubber sealing strip, which adopts the following technical solution: A EPDM rubber sealing strip comprises the following components in parts by weight: 150-180 parts EPDM rubber, 60-90 parts carbon black, 8-12 parts silica, 3-8 parts peroxide vulcanizing agent, 6-12 parts zinc oxide, 12-16 parts magnesium oxide, 10-18 parts paraffin oil, 1-3 parts accelerator, 1-3 parts stearic acid, 1-3 parts antioxidant, and 1-3 parts coupling agent.

[0006] By adopting the above technical solution, EPDM rubber, as the matrix, provides rubber elasticity and basic mechanical properties. Carbon black, as a core reinforcing agent, is added to the reaction and synergistically improves the tensile strength of EPDM rubber with silica. Then, through the reaction of coupling agents with rubber molecular chains, a chemical bond of "filler-coupling agent-rubber" is formed, reducing filler agglomeration and enhancing interfacial adhesion. Peroxide vulcanizing agents can generate CC crosslinks through free radical reactions, thereby forming a high-density, uniform crosslinked network that provides rigid support for the EPDM rubber sealing strip, allowing stress to be effectively transferred through the crosslinking points, thus improving the tensile strength of the EPDM rubber sealing strip. Furthermore, the addition of zinc oxide and magnesium oxide synergizes with the peroxide vulcanizing agent in the vulcanization process, stabilizing the vulcanization process. Through the synergistic effect of the above raw materials, the prepared EPDM rubber sealing strip exhibits excellent tensile strength.

[0007] Preferably, the EPDM rubber sealing strip further includes processing aid A and processing aid B, wherein processing aid A is at least one of magnesium hydroxide and aluminum hydroxide, and processing aid B is at least one of glyceryl borate, glyceryl monostearate, and glyceryl monomethacrylate.

[0008] By employing the above technical solution, the composite of processing aid A and processing aid B can effectively improve the tensile strength of EPDM rubber sealing strips. Magnesium hydroxide and aluminum hydroxide have hydroxyl groups on their surfaces, and glycerol borate ester can act as a molecular bridge. The borate ester groups can form coordination bonds with the metal ions on the surface of processing aid A. The carbon chains in the glycerol borate ester can entangle with the molecular chains of EPDM rubber, forming a chemical-physical dual crosslinking. This enhances the interfacial adhesion between processing aid A and the EPDM rubber matrix. Furthermore, the coordination effect between glycerol borate ester and processing aid A effectively reduces the aggregation of processing aid A, thereby reducing the hindrance to the movement of EPDM rubber molecular chains. Simultaneously, the plasticizing effect of glycerol borate ester, through coordination adsorption, can be more evenly distributed around the filler, enhancing the mobility of the chain segments and thus improving the tensile strength of the EPDM rubber sealing strip.

[0009] Glyceryl monostearate can form hydrogen bonds with the hydroxyl groups on the surface of magnesium hydroxide and aluminum hydroxide through its polar hydroxyl groups, forming a coating layer on the surface of filler particles, effectively reducing filler agglomeration. Furthermore, the long-chain alkyl groups of glyceryl monostearate have good compatibility with the molecular chains of EPDM rubber, which can reduce the surface energy of the filler-rubber interface and promote the bonding between the filler and the EPDM rubber matrix, thereby effectively improving the tensile strength of EPDM rubber sealing strips.

[0010] Preferably, the processing aid A is 20-40 parts by weight.

[0011] By adopting the above technical solution, when the weight of processing aid A is between 20 and 40 parts, the polar groups on the surface of processing aid A can form hydrogen bonds or coordination with the polar groups of processing aid B, resulting in excellent tensile strength of the prepared EPDM rubber sealing strip. When the weight of processing aid A is less than 20 parts, the interaction sites between processing aid A and processing aid B are limited, and sufficient interfacial bonding network cannot be formed, resulting in limited tensile strength of the prepared EPDM rubber sealing strip. When the weight of processing aid A is greater than 40 parts, there are more filler particles, which are prone to agglomeration and stress concentration points, thus reducing the tensile strength of the EPDM rubber sealing strip.

[0012] Preferably, the processing aid A is magnesium hydroxide.

[0013] Preferably, the magnesium hydroxide is present in 25-35 parts by weight.

[0014] By adopting the above technical solution, magnesium hydroxide and aluminum hydroxide, being metal hydroxides, can release water vapor upon thermal decomposition, absorbing heat and diluting flammable gases. Simultaneously, magnesium oxide and aluminum oxide are generated to cover the surface, thereby inhibiting the combustion of EPDM rubber sealing strips and achieving a flame-retardant effect. Specifically, the decomposition temperature of magnesium hydroxide is 340-430℃, while that of aluminum hydroxide is 220-250℃. The higher decomposition temperature of magnesium hydroxide effectively reduces the premature release of water of crystallization, ensuring sufficient interfacial reaction with processing aid B. Furthermore, magnesium hydroxide has a larger specific surface area, providing more hydroxyl groups to react with processing aid B, resulting in EPDM rubber sealing strips with more ideal tensile strength.

[0015] Magnesium hydroxide can also be used as a processing aid A. During decomposition, it releases water vapor, absorbs heat and dilutes flammable gases, and generates magnesium oxide to cover the surface, thereby inhibiting the combustion of EPDM rubber sealing strips and achieving a flame-retardant effect.

[0016] When the weight of magnesium hydroxide is between 25 and 35 parts, the resulting EPDM rubber sealing strip has both ideal tensile strength and flame retardant effect. When the weight of magnesium hydroxide is less than 25 parts, the insufficient amount of magnesium hydroxide results in limited interaction sites with processing aid B, making it impossible to form a sufficient interfacial bonding network. Consequently, the effect of improving the tensile strength of the EPDM rubber sealing strip is not significant. When the weight of magnesium hydroxide is greater than 35 parts, the excessive amount of magnesium hydroxide added is prone to agglomeration. The agglomerates have gaps or weak bonding areas at the interface with the EPDM rubber, causing cracks to appear at the agglomerates when the EPDM rubber sealing strip is stretched, thus affecting the tensile strength of the EPDM rubber sealing strip.

[0017] Preferably, the processing aid B is present in parts by weight of 3-5 parts.

[0018] By adopting the above technical solution, when the weight of processing aid B is 3-5 parts, the molecules of processing aid B can cover the active sites on the surface of processing aid A, ensuring the coordination between processing aid B and processing aid A, and effectively improving the tensile strength of EPDM rubber sealing strips. When the weight of processing aid B is less than 3 parts, processing aid B cannot coat the polar hydroxyl groups on the surface of processing aid A, resulting in insufficient coupling at the "filler-rubber" interface, unsatisfactory filler dispersion and stress transfer efficiency, leading to lower tensile strength of the resulting EPDM rubber sealing strips. When the weight of processing aid B is greater than 5 parts, the excessive polar groups of processing aid B will increase the viscosity of the rubber compound, leading to a sharp increase in mixing energy consumption, rough extrusion surface, and even strip breakage. Moreover, processing aid B is prone to agglomeration or migration in the EPDM rubber matrix, forming a "free aid phase," which weakens the interfacial adhesion and causes a decrease in tensile strength.

[0019] Preferably, the processing aid B is a glycerol borate ester.

[0020] By adopting the above technical solution, glycerol borate ester can act as a molecular bridge. The borate ester group can form coordination bonds with the metal ions on the surface of processing aid A. The carbon chain in glycerol borate ester can entangle with the molecular chain of EPDM rubber to form a chemical-physical double crosslinking, which improves the interfacial adhesion between processing aid A and EPDM rubber matrix. This is more stable than the hydrogen bonding of glycerol monostearate and the ring-opening reaction of glycerol monomethacrylate.

[0021] The decomposition temperature of glycerol borate ester matches that of magnesium hydroxide, allowing it to exist stably at the vulcanization temperature of peroxide vulcanizing agents. Without affecting the free radicals generated by the decomposition of peroxide vulcanizing agents, it can also "shield" the active sites on the surface of magnesium hydroxide through coordination, reducing free radical adsorption loss, increasing the crosslinking density by 10-15%, and making the vulcanized rubber network more uniform.

[0022] Glyceryl borate itself also has a flame retardant synergistic effect. When combined with magnesium hydroxide, it forms a triple flame retardant mechanism of "endothermic-char-oxygen barrier". When magnesium hydroxide is heated and releases water vapor to dilute the combustible gas, glyceryl borate decomposes to generate borate. The low-melting-point borate can form a composite ceramic carbon layer with the metal oxides generated by the decomposition of processing aid A, which significantly improves the high temperature resistance and strength of the carbon layer and prevents the spread of flame.

[0023] Glyceryl borate itself can also participate in the reaction as a low-temperature resistant additive. Glyceryl borate can act as an internal plasticizer, inserting into the rubber molecular chains, weakening the intermolecular forces, lowering the glass transition temperature, and enabling the chain segments to maintain their mobility at low temperatures.

[0024] Preferably, the mass ratio of processing aid B to processing aid A is 1:6-10.

[0025] By adopting the above technical solution, when the mass ratio of processing aid B to processing aid A is in the range of 1:6-10, the resulting EPDM rubber sealing strip exhibits excellent tensile strength and a certain flame-retardant effect. When the proportion of processing aid B is too high, the molecules of processing aid B become too dense, leading to an increase in the viscosity of the rubber compound. This hinders the chain segment movement of the EPDM rubber, resulting in a decrease in the tensile strength of the EPDM rubber sealing strip. When the proportion of processing aid A is too high, processing aid B cannot effectively encapsulate the particles of processing aid A, resulting in poor filler dispersion and easy formation of agglomerates. This weakens the interfacial adhesion between the filler and the EPDM rubber matrix, reduces stress transfer efficiency, and thus makes the improvement in the tensile strength of the sealing strip insignificant. In some cases, the tensile strength may even decrease due to stress concentration points formed by filler agglomeration. Secondly, this application provides a method for preparing an EPDM rubber sealing strip, which adopts the following technical solution: A method for preparing an EPDM rubber sealing strip, comprising the following steps: S1: Ethylene propylene diene monomer (EPDM) rubber, carbon black, silica, zinc oxide, magnesium oxide, paraffin oil, stearic acid, antioxidant, coupling agent and other raw materials are mixed in the formula amount and then mixed in the reaction system in the formula amount to obtain the compound rubber. S2: Cool and shape the compounded rubber to obtain EPDM rubber sealing strips.

[0026] By employing the above-mentioned technical means, this application prepares EPDM rubber sealing strips through a single-stage mixing, a two-stage mixing, cooling, and shaping process. The process is simple and easy to operate, thereby obtaining an EPDM rubber sealing strip with excellent tensile strength.

[0027] In summary, this application includes at least one of the following beneficial technical effects: 1. This application uses EPDM rubber as the matrix to provide rubber elasticity and basic mechanical properties. Carbon black can be added to the reaction as a core reinforcing agent and synergistically improve the tensile strength of EPDM rubber with silica. Then, through the reaction of coupling agent with rubber molecular chain, a chemical connection of "filler-coupling agent-rubber" is formed, which reduces filler agglomeration and enhances interfacial adhesion. Peroxide vulcanizing agent can generate CC crosslinks through free radical reaction, thereby forming a high-density and uniform crosslink network, providing rigid support for EPDM rubber sealing strip and effectively improving the tensile strength of EPDM rubber sealing strip; 2. This application combines magnesium hydroxide and glycerol borate. Glycerol borate acts as a molecular bridge to effectively improve the interfacial adhesion between magnesium hydroxide and the EPDM rubber matrix. Furthermore, the plasticizing effect of glycerol borate can enhance the chain segment mobility of EPDM rubber molecules, effectively improving the tensile strength of the EPDM rubber sealing strip. At the same time, magnesium hydroxide itself can act as a flame retardant, and glycerol borate itself can act as a low-temperature resistant additive. As a result, the obtained EPDM rubber sealing strip has excellent tensile strength, flame retardant effect, and low-temperature resistance. 3. In this application, the mass ratio of processing aid B to processing aid A is set in the range of 1:6-10. The resulting EPDM rubber sealing strip has excellent tensile strength, reduces the phenomenon of increased rubber viscosity caused by excessive processing aid B, and reduces the phenomenon of weak interfacial bonding between filler and ternary rubber matrix caused by excessive processing aid A. Detailed Implementation

[0028] The raw materials in this application include the following: Glyceryl borate esters: Commercially available products with CAS number 49625-59-42; Glyceryl monostearate: a commercially available product with CAS number 123-94-4; Glyceryl monomethyl vinyl ester: a commercially available product with CAS number 5919-74-4; Peroxide vulcanizing agent: selected from alkyl peroxides or diacyl peroxides, this application takes alkyl peroxides as an example; Coupling agent: selected from silane coupling agents or titanate coupling agents; this application takes silane coupling agent as an example.

[0029] The present application will be further described in detail below with reference to embodiments and comparative examples.

[0030] Example 1

[0031] A EPDM rubber sealing strip comprises the following components in parts by weight: 160g EPDM rubber, 75g carbon black, 10g silica, 6g alkyl peroxide, 9g zinc oxide, 14g magnesium oxide, 14g paraffin oil, 2g accelerator TMTD, 2g stearic acid, 2g antioxidant MB, and 2g alkyl coupling agent.

[0032] A method for preparing an EPDM rubber sealing strip, comprising the following steps: S1: Ethylene propylene diene monomer (EPDM) rubber, carbon black, silica, zinc oxide, magnesium oxide, paraffin oil, stearic acid, antioxidant, and coupling agent are mixed in the formula amount for the first stage of mixing. Then, peroxide vulcanizing agent and accelerator are added to the reaction system in the formula amount for the second stage of mixing to obtain the compound rubber. S2: Cool and shape the compounded rubber to obtain EPDM rubber sealing strips.

[0033] The first stage of mixing is carried out at a temperature of 120℃ for 10 minutes; the second stage of mixing is carried out at a temperature of 80℃ for 3 minutes.

[0034] Example 2-3 Examples 2-3 are based on the preparation method of Example 1, but the composition of the EPDM rubber sealing strip is adjusted as shown in Table 1.

[0035] Comparative Examples 1-3 Comparative Examples 1-3 are based on the preparation method of Example 1, but the composition of the EPDM rubber sealing strip is adjusted as shown in Table 1.

[0036] Performance testing The EPDM rubber sealing strips of Examples 1-3 and Comparative Examples 1-3 were analyzed, and the specific testing methods are as follows: 1. Tensile strength The tensile strength of EPDM rubber sealing strips was tested according to GB / T 528-2009 standard (dumbbell-shaped specimen).

[0037] Based on the above detection method, the test results of Examples 1-3 and Comparative Examples 1-3 were obtained, as shown in Table 1 below.

[0038] Table 1. Composition and performance test results of EPDM rubber sealing strips in Examples 1-3 and Comparative Examples 1-3.

[0039] Referring to Table 1, a comparison of Examples 1-3 and Comparative Examples 1-3 shows that the tensile strength of the EPDM rubber sealing strips obtained in Examples 1-3 is significantly higher than that obtained in Comparative Examples 1-3. This may be because carbon black acts as a core reinforcing agent during the preparation process, significantly improving the tensile strength of the EPDM rubber sealing strips. The addition of silica can synergistically work with carbon black to construct a "dual filler network," further enhancing the tensile strength of the EPDM rubber sealing strips. The peroxide vulcanizing agent generates CC crosslinks through free radical reactions, providing rigid support for the EPDM rubber sealing strips, thereby increasing their tensile strength.

[0040] Example 4

[0041] Example 4 is based on the preparation method of Example 1, with the addition of 30g of magnesium hydroxide (processing aid A) and 4g of glycerol borate ester (processing aid B) in S1, while other conditions remain unchanged.

[0042] Examples 5-9 Examples 5-9 are based on the preparation method of Example 4, but the types of processing aid A and processing aid B are adjusted, as shown in Table 2.

[0043] Performance testing The EPDM rubber sealing strips of Examples 4-9 above were analyzed, and the specific testing methods are as follows: 1. Flame retardancy The oxygen index method was used to test the flame retardant effect of EPDM rubber sealing strips according to the method specified in GB / T 10707-2008.

[0044] 2. Low temperature resistance The low-temperature resistance of EPDM rubber sealing strips was tested according to the method specified in GB / T 7758-2020. The samples were stretched to 50% elongation at standard temperature, cooled to -70℃ and held for 10 minutes, and then heated at a rate of 1℃ / min. The shrinkage rate of the samples at different temperatures was recorded. By plotting temperature-shrinkage rate curves, the temperatures at which 30% and 70% shrinkage rates were achieved (TR30, TR70) were determined, thus characterizing the material's low-temperature elasticity retention capability.

[0045] Based on the above detection method, the test results of Examples 1 and 4-9 were obtained, as shown in Table 2 below.

[0046] Table 2. Types and performance tests of processing aid A and processing aid B in Examples 1 and 4-9.

[0047] Referring to Table 2, a comparison of Examples 1 and 4-9 shows that the tensile strength of the EPDM rubber sealing strips obtained in Examples 4-9 is significantly higher than that of the EPDM rubber sealing strips obtained in Example 1. Further comparison of Examples 4-6 and 7-9 shows that the tensile strength of the EPDM rubber sealing strips obtained in Examples 4-6 is higher than that obtained in Examples 7-9. This indicates that when processing aid A is magnesium hydroxide, it has a better effect on improving the tensile strength of the EPDM rubber sealing strips. This may be due to the denser hydroxyl groups on the surface of magnesium hydroxide. With high viscosity and strong polarity, it can form a more stable bond with processing aid B. When processing aid B is glycerol borate, the resulting EPDM rubber sealing strip has the best tensile strength. This may be because glycerol borate can act as a molecular bridge, strongly connecting the borate group to the surface of magnesium hydroxide and entangled with the molecular chain of EPDM rubber through carbon chain, thereby improving the interfacial adhesion between magnesium hydroxide and EPDM rubber. At the same time, the coordination effect between glycerol borate and magnesium hydroxide effectively reduces the agglomeration of magnesium hydroxide, thus effectively improving the tensile strength of EPDM rubber sealing strip.

[0048] Compared to Example 1, the flame-retardant effect of the EPDM rubber sealing strips obtained in Examples 4-9 was significantly improved. This is likely because processing aid A, as a metal hydroxide, releases water vapor during heating, absorbing heat and diluting flammable gases, thus playing a flame-retardant role. Among these, the flame-retardant effect of the EPDM rubber sealing strips obtained in Examples 4-6 is superior to that obtained in Examples 7-9. This is likely because magnesium hydroxide has a higher decomposition temperature, allowing the generated water vapor to disperse more evenly, resulting in a more ideal effect on diluting flammable gases. Furthermore, the generated magnesium peroxide can cover the surface, inhibiting the combustion of the EPDM rubber sealing strip. Additionally, glyceryl borate ester has a synergistic flame-retardant effect, forming a triple flame-retardant mechanism of "heat absorption-char formation-oxygen barrier" with magnesium hydroxide, further improving the flame-retardant effect of the EPDM rubber sealing strip.

[0049] Compared to Example 1, the low-temperature resistance of the EPDM rubber sealing strips obtained in Examples 4-9 was improved. This may be because processing aid B can promote the movement of EPDM rubber molecular chain segments under low-temperature conditions.

[0050] Examples 10-13 Examples 10-13 are based on the preparation method of Example 4, but the amount of magnesium hydroxide added is adjusted, as shown in Table 3.

[0051] Comparative Example 4-5 Comparative Examples 4-5 were prepared using the same method as in Example 4, but with adjustments made to the amount of magnesium hydroxide added. The specific adjustments are shown in Table 3.

[0052] The EPDM rubber sealing strips of Examples 10-13 and Comparative Examples 4-5 were subjected to the above performance tests, and the test results are shown in Table 3.

[0053] Table 3. Magnesium hydroxide addition amount and performance test results for Examples 4, 10-13, and Comparative Examples 4-5.

[0054] Referring to Table 3, comparing Examples 4, 10-13, and 4-5, it can be seen that when the amount of magnesium hydroxide added is 20-40g, especially when the amount of magnesium hydroxide added is in the range of 25-35g, the resulting EPDM rubber sealing strip has excellent tensile strength. The tensile strength of the EPDM rubber sealing strip obtained in Comparative Example 4-5 is significantly lower than that of the EPDM rubber sealing strips obtained in Examples 4 and 10-13. This may be because when the amount of magnesium hydroxide added is too small, the interaction sites between magnesium hydroxide and glycerol borate are limited, and the two cannot form a sufficient interfacial bonding network. When the amount of magnesium hydroxide added is too large, agglomeration is likely to occur, forming stress concentration points, thus resulting in an unsatisfactory effect on improving the tensile strength of the EPDM rubber sealing strip.

[0055] Examples 14-15 Examples 14-15 are based on the preparation method of Example 4, but the amount of glycerol borate ester added is adjusted, as shown in Table 4.

[0056] Comparative Examples 6-7 Comparative Examples 6-7 were prepared using the same method as in Example 4, but with adjustments made to the amount of glycerol borate added. The specific adjustments are shown in Table 4.

[0057] The EPDM rubber sealing strips of Examples 14-15 and Comparative Examples 6-7 were subjected to the above performance tests, and the test results are shown in Table 4.

[0058] Table 4. Glyceryl borate ester addition amount and performance test results for Examples 4, 14-15 and Comparative Examples 6-7

[0059] Referring to Table 4, and comparing Examples 4, 14-15, and 6-7, it can be seen that when the amount of glycerol borate added is in the range of 3-5g, the resulting EPDM rubber sealing strip has ideal tensile strength. This may be because when the amount of glycerol borate added is too small, the glycerol borate cannot coat the polar hydroxyl groups on the surface of magnesium hydroxide, resulting in poor filler dispersion and stress transfer efficiency, leading to low tensile strength. When the amount of glycerol borate added is too large, it will increase the viscosity of the rubber compound, thus reducing the tensile strength.

[0060] Examples 16-17 Examples 16-17 are based on the preparation method of Example 4, with the total amount of magnesium hydroxide and glycerol borate ester maintained at 34g, and the mass ratio of glycerol borate ester to magnesium hydroxide adjusted as shown in Table 5.

[0061] Comparative Examples 8-9 Comparative Examples 8-9 were prepared using the same method as in Example 4, but with the total amount of magnesium hydroxide and glycerol borate ester maintained at 34 g. The mass ratio of glycerol borate ester to magnesium hydroxide was adjusted as shown in Table 5.

[0062] The EPDM rubber sealing strips of Examples 16-17 and Comparative Examples 8-9 were subjected to the above performance tests, and the test results are shown in Table 5.

[0063] Table 5. Mass ratio and performance test results of glycerol borate ester to magnesium hydroxide in Examples 4, 16-17, and Comparative Examples 8-9.

[0064] Referring to Table 5, and comparing Examples 4, 16-17, and 8-9, it can be seen that when the mass ratio of glycerol borate to magnesium hydroxide is 1:6-10, especially when the mass ratio of glycerol borate to magnesium hydroxide is 1:7.5, the resulting EPDM rubber sealing strip has excellent tensile strength. This may be because when the proportion of magnesium hydroxide is too large, the glycerol borate cannot effectively encapsulate the magnesium hydroxide, easily forming agglomerates, which weakens the interfacial adhesion between the filler and the EPDM rubber matrix, resulting in an unsatisfactory effect on improving tensile strength. When the proportion of glycerol borate is too large, it easily leads to an increase in the viscosity of the rubber compound, which hinders the chain segment movement of the EPDM rubber, resulting in unsatisfactory tensile strength.

[0065] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A ternary ethylene propylene rubber sealing strip, characterized in that, The product comprises the following components in parts by weight: 150-180 parts EPDM rubber, 60-90 parts carbon black, 8-12 parts silica, 3-8 parts peroxide vulcanizing agent, 6-12 parts zinc oxide, 12-16 parts magnesium oxide, 10-18 parts paraffin oil, 1-3 parts accelerator TMTD, 1-3 parts stearic acid, 1-3 parts antioxidant MB, and 1-3 parts coupling agent; It also includes processing aid A and processing aid B, wherein processing aid A is magnesium hydroxide and processing aid B is glycerol borate ester; The processing aid A is present in parts by weight of 20-40 parts; The processing aid B is present in parts by weight of 3-5 parts; The mass ratio of processing aid B to processing aid A is 1:6-10.

2. The EPDM weatherseal of claim 1, wherein, The magnesium hydroxide is present in parts by weight of 25-35.

3. A process for the production of a ternary ethylene-propylene rubber sealing strip according to any one of claims 1-2, characterized in that, Includes the following steps: S1: Ethylene propylene diene monomer (EPDM) rubber, carbon black, silica, zinc oxide, magnesium oxide, paraffin oil, stearic acid, antioxidant, coupling agent, and processing aid A and processing aid B are mixed in the formula amount for a first stage. Then, peroxide vulcanizing agent and accelerator are added to the reaction system in the formula amount for a second stage of mixing to obtain the compound rubber. S2: Cool and shape the compounded rubber to obtain EPDM rubber sealing strips.

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