Low odor epdm seal and method of making same

Abstract

The application relates to the technical field of rubber sealing materials, and particularly discloses a low-odor EPDM sealing ring and a preparation method thereof. The raw materials for preparing the low-odor EPDM sealing ring include ethylene propylene diene rubber, modified calcined kaolin, white carbon black, N-990 carbon black, paraffin oil, stearic acid, zinc oxide, a deodorizing agent, a vulcanizing agent and a crosslinking agent. The calcined kaolin is modified by using methacryloxy silane and a composite intercalating agent. The methacryloxy silane forms an organic coating on the surface of the calcined kaolin, thereby improving the compatibility of the calcined kaolin and the rubber. The composite intercalating agent is inserted into the interlayer of the kaolin, which is beneficial to the rubber matrix entering the interlayer and combining with the kaolin, improves the tensile strength and the tensile stress of the rubber compound, and the modified calcined kaolin and the N-990 carbon black have a synergistic effect, so that a better reinforcing effect is achieved, and the rubber is balanced between elasticity and strength.

Description

Technical Field

[0001] This application relates to the field of rubber sealing materials technology, and in particular to a low-odor EPDM sealing ring and its preparation method. Background Technology

[0002] With the rapid development of the automotive industry, the requirements for sealing performance and user experience of automotive air conditioning systems and in-vehicle refrigerators are becoming increasingly stringent. As a key component of these devices, sealing rings not only need to possess good mechanical properties and durability, but also need to meet the requirements of low odor and low volatility to avoid affecting the air quality inside the vehicle due to the odor of the sealing material, thereby reducing the user experience.

[0003] In the existing technology, in order to improve the deodorization effect, it is necessary to increase the amount of carbon black added to the rubber matrix. However, due to the difference in the interfacial properties between carbon black and rubber matrix, and the fact that a higher amount of carbon black added can easily lead to an increase in the hardness of the rubber, while the elongation and elasticity and other mechanical properties will decrease, thus affecting its performance. Summary of the Invention

[0004] To achieve better reinforcement and maintain a balance between elasticity and strength in the rubber sealing ring, this application provides a low-odor EPDM sealing ring and its preparation method.

[0005] Firstly, this application provides a low-odor EPDM sealing ring, which adopts the following technical solution:

[0006] A low-odor EPDM sealing ring, by weight, is prepared from the following raw materials:

[0007] 90-110 parts of EPDM rubber, 45-55 parts of modified calcined kaolin, 10-30 parts of silica, 30-45 parts of N-990 carbon black, 8-12 parts of paraffin oil, 0.9-1.5 parts of stearic acid, 5.5-7.5 parts of zinc oxide, 0.8-1.2 parts of deodorizer, 4-6 parts of vulcanizing agent, and 1.8-2.2 parts of crosslinking agent;

[0008] The raw materials for preparing the modified calcined kaolin include calcined kaolin, methacryloxysilane, and a composite intercalating agent, wherein the weight ratio of the calcined kaolin, methacryloxysilane, and the composite intercalating agent is 1:(0.1-0.3):(0.8-1.2).

[0009] By adopting the above technical solution, the sealing ring of this application uses EPDM rubber as the matrix material, and adds modified calcined kaolin, N-990 carbon black, and silica as composite reinforcing agents. An appropriate amount of N-990 carbon black can significantly improve the mechanical properties and wear resistance of the rubber, while the introduction of modified calcined kaolin can reduce the adverse effects on the rubber caused by excessive N-990 carbon black addition, improving the tensile strength and tensile stress of the rubber compound. The synergistic effect of modified calcined kaolin and N-990 carbon black can achieve a better reinforcing effect, maintaining a balance between elasticity and strength in the rubber. Silica can optimize the rheological properties of the rubber during processing; silica has a higher specific surface area and porosity, enhancing the elasticity and softness of the rubber. Stearic acid and zinc oxide work synergistically to form active complexes during vulcanization, further promoting the cross-linking reaction and improving the cross-linking density and heat resistance. The deodorizer can decompose and adsorb the irritating odor generated during rubber vulcanization. Paraffin oil has good compatibility with EPDM rubber and can improve the processing performance of EPDM rubber.

[0010] Furthermore, this application modifies calcined kaolin using methacryloxysilane and a composite intercalating agent, significantly improving the dispersibility and compatibility of calcined kaolin in rubber and enhancing the interfacial bonding ability between kaolin and rubber. Good dispersibility helps maintain the elasticity of rubber, enhancing its ability to recover its original shape after pressure removal. Specifically, methacryloxysilane forms an organic coating on the surface of calcined kaolin, thereby improving its compatibility with rubber. The composite intercalating agent can disrupt the hydrogen bonds formed between kaolin layers; that is, the composite intercalating agent forms hydrogen bonds with the hydroxyl groups of the aluminum-oxygen octahedrons and the oxygen atoms of the silicon-oxygen tetrahedra between kaolin layers, thus inserting itself into the interlayer space of kaolin, widening the interlayer spacing, reducing the surface energy between layers, and decreasing the aggregation of kaolin particles. This results in more uniform dispersion of kaolin in the organic phase and facilitates the entry of the rubber matrix into the interlayer space, combining with kaolin to form an organic-inorganic composite material.

[0011] Preferably, the composite intercalating agent is composed of acetamide and salicylamide, wherein the weight ratio of acetamide to salicylamide is 1:(0.2-0.4).

[0012] By adopting the above technical solution, acetamide and salicylamide work synergistically. After the composite intercalating agent enters the interlayer of kaolin, it is arranged in a near-vertical and orderly manner with amino groups facing the aluminum oxide octahedral sheets of kaolin. This breaks the hydrogen bond between the kaolin layers and forms new hydrogen bonds with the inner hydroxyl groups of the silicon oxide surface between the kaolin layers through the amino groups. Furthermore, the methyl groups of the acetamide molecules facing the silicon oxide tetrahedral sheets are also embedded in the trigonal cavities, which further increases the interlayer spacing of the kaolin.

[0013] Preferably, the method for preparing the modified calcined kaolin is as follows:

[0014] (1) Calcined kaolin and dimethyl sulfoxide solution were ultrasonically vibrated at 50-60℃ for 18-22h, filtered and dried to obtain dimethyl sulfoxide / kaolin composite.

[0015] (2) Dissolve the composite intercalating agent in an ethanol solution and stir to form a composite hydrolysate. Then mix the dimethyl sulfoxide / kaolin composite with the composite hydrolysate, stir magnetically for 2-4 hours, wash 2-3 times, filter and dry to obtain intercalated kaolin.

[0016] (3) Dissolve methacryloyloxysilane in ethanol solution and stir to form silane hydrolysate; then place the silane hydrolysate and intercalated kaolin in a ball mill with a vibration frequency of 35-39 Hz and ball mill for 3-4 hours to complete the pretreatment, then filter, wash, dry and pulverize to obtain modified calcined kaolin.

[0017] By adopting the above technical solution, calcined kaolin is modified with methacryloyloxysilane and a composite intercalating agent, making it more uniformly dispersed in the rubber matrix, enhancing the interfacial bonding between kaolin and rubber, improving the stability of the rubber molecular chain, and thus improving the tensile stress and tensile strength of the rubber.

[0018] Preferably, the methacryloyloxysilane is at least one selected from γ-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, and 3-methacryloyloxypropyltriisooxysilane.

[0019] By adopting the above technical solution, the silanol generated by the hydrolysis of alkoxy groups in the methacryloyloxysilane molecule undergoes a condensation reaction with the hydroxyl groups on the surface of kaolin to form a silicon-oxygen bond. Meanwhile, the methacryloyloxy group undergoes a copolymerization reaction with EPDM rubber to form a strong chemical bond, thereby achieving a chemical bridge between inorganic and organic materials. This not only improves the dispersibility of kaolin in the organic phase but also enhances the compatibility between kaolin and the rubber matrix.

[0020] Preferably, the deodorizing agent is deodorizing agent XJF-02.

[0021] By adopting the above technical solution, the deodorizer XJF-02 can effectively reduce and suppress the odor caused by rubber additives and residual monomers in EPDM rubber. It reacts directly with low-molecular-weight mixtures (such as functional groups containing amino nitrogen and hydrogen sulfide) through chemical chelation, causing them to lose their volatility, thereby achieving the purpose of deodorization.

[0022] Preferably, the vulcanizing agent is at least one of di-tert-butyl peroxide diisopropylbenzene, diisopropylbenzene peroxide, zinc dibutyl dithiocarbamate, and N-cyclohexyl-2-benzothiazole sulfenamide.

[0023] Preferably, the crosslinking agent is at least one selected from triallyl isocyanurate, triallyl cyanurate, and crosslinking agent CA94-50.

[0024] By adopting the above technical solution, the vulcanizing agent and the crosslinking agent work synergistically to form a uniform and stable crosslinking network structure during the vulcanization process of rubber, which not only improves the heat resistance and compression set performance of the vulcanized rubber, but also maintains good elasticity and mechanical properties.

[0025] Preferably, the particle size of the calcined kaolin is 4000-6000 mesh.

[0026] By adopting the above technical solution, calcined kaolin with a particle size of 4000-6000 mesh has a better dispersion effect in this application.

[0027] Secondly, the method for preparing a low-odor EPDM sealing ring provided in this application adopts the following technical solution:

[0028] A method for preparing a low-odor EPDM sealing ring includes the following steps:

[0029] First, weigh the raw materials according to the stated composition ratio, and melt-blend EPDM rubber, modified calcined kaolin, silica, N-990 carbon black, paraffin oil, stearic acid, zinc oxide, and deodorizing agent at 140-150℃ to obtain a premix. Next, mix the premix with vulcanizing agent and crosslinking agent evenly, and vulcanize and mold it using a vulcanizing machine at 150-180℃. Finally, trim the edges using a stamping device to obtain a low-odor EPDM sealing ring.

[0030] Preferably, the vulcanization includes a first vulcanization and a second vulcanization. The first vulcanization is carried out at a temperature of 160-180°C for 10-15 minutes and at a pressure of 10-12 MPa. The second vulcanization is carried out at a temperature of 150-160°C for 2-3 hours and at a pressure of 7-9 MPa.

[0031] By adopting the above technical solution, using a composite filler system of modified calcined kaolin, silica, and N-990 carbon black, combined with a two-stage vulcanization process, the mechanical properties of the sealing ring are significantly improved. The synergistic effect of modified kaolin and silica enhances the tear strength and elasticity of the rubber, while carbon black provides good abrasion resistance and anti-aging properties. The two-stage vulcanization process further optimizes the cross-linked network structure, giving the sealing ring higher tensile strength, elongation at break, and compression set. During the high-temperature mixing process, the deodorizing agent can chemically react or physically adsorb odor molecules in the rubber, reducing the release of volatile organic compounds (VOCs), thereby significantly reducing the odor intensity of the sealing ring and meeting the low-odor requirements of the automotive, home appliance, and other industries.

[0032] In summary, this application includes at least one of the following beneficial technical effects:

[0033] The sealing ring of this application uses EPDM rubber as the base material, and modified calcined kaolin, N-990 carbon black, and silica as composite reinforcing agents. Appropriate amounts of N-990 carbon black can significantly improve the mechanical properties and wear resistance of the rubber, while the introduction of modified calcined kaolin can reduce the adverse effects of excessive N-990 carbon black addition, improving the tensile strength and tensile stress of the rubber compound. The synergistic effect of modified calcined kaolin and N-990 carbon black achieves a better reinforcing effect, maintaining a balance between elasticity and strength in the rubber. Silica can optimize the rheological properties of the rubber during processing; silica has a higher specific surface area and porosity, enhancing the elasticity and softness of the rubber. Stearic acid and zinc oxide work synergistically to form active complexes during vulcanization, further promoting the cross-linking reaction and increasing the cross-linking density and heat resistance. The deodorizer can decompose and adsorb the irritating odor generated during rubber vulcanization. Paraffin oil has good compatibility with EPDM rubber and can improve the processing performance of EPDM rubber.

[0034] Furthermore, this application modifies calcined kaolin using methacryloxysilane and a composite intercalating agent, significantly improving the dispersibility and compatibility of calcined kaolin in rubber and enhancing the interfacial bonding ability between kaolin and rubber. Good dispersibility helps maintain the elasticity of rubber, enhancing its ability to recover its original shape after pressure removal. Specifically, methacryloxysilane forms an organic coating on the surface of calcined kaolin, thereby improving its compatibility with rubber. The composite intercalating agent can disrupt the hydrogen bonds formed between kaolin layers; that is, the composite intercalating agent forms hydrogen bonds with the hydroxyl groups of the aluminum-oxygen octahedrons and the oxygen atoms of the silicon-oxygen tetrahedra between kaolin layers, thus inserting itself into the interlayer space of kaolin, widening the interlayer spacing, reducing the surface energy between layers, and decreasing the aggregation of kaolin particles. This results in more uniform dispersion of kaolin in the organic phase and facilitates the entry of the rubber matrix into the interlayer space, combining with kaolin to form an organic-inorganic composite material. Detailed Implementation

[0035] The present application will be further described in detail below with reference to the embodiments.

[0036] Preparation Example

[0037] Preparation Example 1

[0038] Preparation of modified calcined kaolin:

[0039] (1) 450g of calcined kaolin and 500mL of dimethyl sulfoxide solution (the ratio of dimethyl sulfoxide to water is 10:1) were ultrasonically vibrated at 50℃ for 18h, filtered and dried to obtain dimethyl sulfoxide / kaolin composite.

[0040] (2) Dissolve 360g of composite intercalating agent (300g of acetamide and 60g of salicylamide) in 95% ethanol solution and stir to form a composite hydrolysate. Then mix the dimethyl sulfoxide / kaolin composite with the composite hydrolysate, stir magnetically for 2 hours, wash twice, filter and dry to obtain intercalated kaolin.

[0041] (3) Dissolve 45g of 3-methacryloxypropyltriethoxysilane in 95% ethanol solution and stir to form silane hydrolysate; then place the silane hydrolysate and intercalated kaolin in a ball mill with a vibration frequency of 35Hz and ball mill for 3h to complete the pretreatment, then filter, wash, dry and pulverize to obtain modified calcined kaolin.

[0042] Preparation Example 2

[0043] Preparation of modified calcined kaolin:

[0044] (1) 500g of calcined kaolin and 550mL of dimethyl sulfoxide solution (the ratio of dimethyl sulfoxide to water is 10:1) were ultrasonically vibrated at 55℃ for 20h, filtered and dried to obtain dimethyl sulfoxide / kaolin composite.

[0045] (2) Dissolve 500g of composite intercalating agent (385g of acetamide and 115g of salicylamide) in 95% ethanol solution and stir to form a composite hydrolysate. Then mix the dimethyl sulfoxide / kaolin composite with the composite hydrolysate, stir magnetically for 3 hours, wash 3 times, filter and dry to obtain intercalated kaolin.

[0046] (3) Dissolve 100g of γ-methacryloxypropyltrimethoxysilane (A-174) in 95% ethanol solution and stir to form silane hydrolysate; then place the silane hydrolysate and intercalated kaolin in a ball mill, the ball mill vibration frequency is 37Hz, and the ball milling is performed for 3.5 hours to complete the pretreatment. Then filter, wash, dry and pulverize to obtain modified calcined kaolin.

[0047] Preparation Example 3

[0048] Preparation of modified calcined kaolin:

[0049] (1) 550g of calcined kaolin and 600mL of dimethyl sulfoxide solution (the ratio of dimethyl sulfoxide to water is 10:1) were ultrasonically vibrated at 60℃ for 22h, filtered and dried to obtain dimethyl sulfoxide / kaolin composite.

[0050] (2) Dissolve 660g of composite intercalating agent (471g of acetamide and 189g of salicylamide) in 95% ethanol solution and stir to form a composite hydrolysate. Then mix the dimethyl sulfoxide / kaolin composite with the composite hydrolysate, stir magnetically for 4 hours, wash 3 times, filter and dry to obtain intercalated kaolin.

[0051] (3) Dissolve 165g of 3-methacryloxypropyltriisooxysilane in 95% ethanol solution and stir to form silane hydrolysate; then place the silane hydrolysate and intercalated kaolin in a ball mill with a vibration frequency of 39Hz and ball mill for 4 hours to complete the pretreatment, then filter, wash, dry and pulverize to obtain modified calcined kaolin.

[0052] Preparation Example 4

[0053] The difference between this preparation example and preparation example 2 is that in step (2), an equal amount of formamide is used instead of acetamide.

[0054] Preparation Example 5

[0055] The difference between this preparation example and preparation example 2 is that in step (2), an equal amount of benzamide is used instead of salicylamide.

[0056] Preparation Example 6

[0057] The difference between this preparation example and preparation example 2 is that in step (2), an equal amount of acrylamide is used instead of the composite intercalating agent.

[0058] Preparation Example 7

[0059] The difference between this preparation example and preparation example 2 is that in step (3), an equal amount of 3-aminopropyltrimethoxysilane is used instead of γ-methacryloyloxypropyltrimethoxysilane.

[0060] Example

[0061] Example 1

[0062] A low-odor EPDM sealing ring comprising the following materials:

[0063] 900g EPDM rubber (Mitsui 3072E(P)M), 450g modified calcined kaolin (prepared in Preparation Example 1), 100g silica (Cabot CAB-O-SIL M5), 300g N-990 carbon black, 80g paraffin oil, 9g stearic acid, 55g zinc oxide (ZNO-80), 8g deodorizer XJF-02, 40g dicumyl peroxide, and 18g triallyl cyanurate.

[0064] The method for preparing the low-odor EPDM sealing ring in this embodiment includes the following steps:

[0065] First, the raw materials are weighed according to the stated composition ratio. EPDM rubber, modified calcined kaolin, silica, N-990 carbon black, paraffin oil, stearic acid, zinc oxide, and deodorizing agent XJF-02 are melt-blended at 140°C to obtain a premix. Then, the premix is ​​mixed evenly with dicumyl peroxide and triallyl cyanurate, and subjected to a first vulcanization at 160°C and 10MPa for 10 minutes. Next, a second vulcanization is performed at 150°C and 7MPa for 2 hours. After the reaction is completed, the edges are trimmed using a stamping device to obtain a low-odor EPDM sealing ring.

[0066] Example 2

[0067] A low-odor EPDM sealing ring comprising the following materials:

[0068] 1000g EPDM rubber (Mitsui 3072E(P)M), 500g modified calcined kaolin (prepared in Preparation Example 2), 200g silica (Cabot CAB-O-SIL M5), 400g N-990 carbon black, 100g paraffin oil, 12g stearic acid, 65g zinc oxide (ZNO-80), 10g deodorizer XJF-02, 50g di-tert-butyl peroxide diisopropylbenzene, and 20g triallyl isocyanurate.

[0069] The method for preparing the low-odor EPDM sealing ring in this embodiment includes the following steps:

[0070] First, the raw materials are weighed according to the stated composition ratio. EPDM rubber, modified calcined kaolin, silica, N-990 carbon black, paraffin oil, stearic acid, zinc oxide, and deodorizing agent XJF-02 are melt-blended at 140°C to obtain a premix. Then, the premix is ​​mixed evenly with di-tert-butyl peroxide diisopropylbenzene and triallyl isocyanurate. The mixture is then subjected to a first vulcanization at 170°C and 11 MPa for 12 minutes. Next, a second vulcanization is performed at 155°C and 8 MPa for 2.5 hours. After the reaction is completed, the edges are trimmed using a stamping device to obtain a low-odor EPDM sealing ring.

[0071] Example 3

[0072] A low-odor EPDM sealing ring comprising the following materials:

[0073] 1100g EPDM rubber (Mitsui 3072E(P)M), 550g modified calcined kaolin (prepared in Preparation Example 3), 300g silica (Cabot CAB-O-SIL M5), 450g N-990 carbon black, 120g paraffin oil, 15g stearic acid, 75g zinc oxide (ZNO-80), 12g deodorizer XJF-02, 60g N-cyclohexyl-2-benzothiazole sulfenamide, and 22g crosslinking agent CA94-50.

[0074] The method for preparing the low-odor EPDM sealing ring in this embodiment includes the following steps:

[0075] First, the raw materials are weighed according to the stated composition ratio. EPDM rubber, modified calcined kaolin, silica, N-990 carbon black, paraffin oil, stearic acid, zinc oxide, and deodorizing agent XJF-02 are melt-blended at 150°C to obtain a premix. Then, the premix is ​​mixed evenly with N-cyclohexyl-2-benzothiazole sulfenamide and crosslinking agent CA94-50. The mixture is then subjected to a first vulcanization at 180°C and 12MPa for 15 minutes. Next, a second vulcanization is performed at 160°C and 9MPa for 3 hours. After the reaction is completed, the edges are trimmed using a stamping device to obtain a low-odor EPDM sealing ring.

[0076] Example 4

[0077] The difference between this embodiment and Example 2 is that the modified calcined kaolin prepared in Example 4 is used.

[0078] Example 5

[0079] The difference between this embodiment and Example 2 is that the modified calcined kaolin prepared in Example 5 is used.

[0080] Comparative Example

[0081] Comparative Example 1

[0082] A low-odor EPDM sealing ring, which differs from Example 2 in that it uses modified calcined kaolin prepared in Preparation Example 6.

[0083] Comparative Example 2

[0084] A low-odor EPDM sealing ring, which differs from Example 2 in that it uses modified calcined kaolin prepared in Preparation Example 7.

[0085] Comparative Example 3

[0086] A low-odor EPDM sealing ring differs from Example 2 in that it uses an equal amount of unmodified kaolin instead of modified calcined kaolin.

[0087] Comparative Example 4

[0088] A low-odor EPDM sealing ring differs from Example 2 in that it uses an equal amount of N-990 carbon black instead of modified calcined kaolin.

[0089] Comparative Example 5

[0090] A low-odor EPDM sealing ring, which differs from Example 2 in that no silica is added.

[0091] Comparative Example 6

[0092] A low-odor EPDM sealing ring, which differs from Example 2 in that it does not contain N-990 carbon black.

[0093] Performance testing

[0094] The low-odor EPDM sealing rings prepared in Examples 1-5 and Comparative Examples 1-6 were subjected to hardness testing, compression set testing, tensile strength testing, elongation at break testing, and odor testing. The test results are recorded in Table 1.

[0095] Hardness test: The hardness of the obtained low-odor EPDM sealing ring was tested according to GB / T 531.2-2009 standard.

[0096] Compression set test: According to GB / T7759.2-2014 standard, it is expressed by testing the percentage of compression set at 0℃ / 72 hours.

[0097] Tensile strength and elongation at break: Tensile strength and elongation at break were tested according to ASTM-D3574-08.

[0098] Odor Test: The odor test was conducted according to Q / BYDQ-A1901.404-2018 "Test Method for Odor of Automotive Parts". No water was added to the test container. The container was tightly sealed and placed in a preheated electrically heated constant-temperature drying oven to (80±2)℃ for (2h±10min). Afterward, the test container was removed from the oven and cooled back to (60±5)℃ for evaluation by five assessors. The container was then placed back in the drying oven at (80±2)℃ for 30min, and a second evaluation was conducted by the five assessors. The average value of the two evaluations was taken as the final conclusion.

[0099] Table 1

[0100]

[0101]

[0102] Based on the data from Examples 2 and 4-5 and Table 1, it can be seen that: formamide has a less effective intercalation effect on kaolin than acetamide. Formamide molecules cannot enter the complex trigonal cavities of the silica-oxygen surface of kaolin, while the methyl groups of acetamide molecules can embed into the complex trigonal cavities of the silica-oxygen surface of kaolin, further increasing the interlayer spacing of kaolin and achieving a good intercalation effect. This gives the material suitable toughness and resilience, thus enhancing the sealing effect of the sealing ring. Benzamide has a less effective intercalation effect on kaolin than salicylamide. Salicylic acid molecule contains hydroxyl groups and has a stronger binding effect with kaolin. Therefore, salicylamide has a better intercalation effect on kaolin than benzamide, resulting in better dispersion of kaolin in EPDM rubber, thereby significantly improving the tensile strength and tensile stress of the material.

[0103] According to the data in Example 2, Comparative Example 1, and Table 1, the modification effect of using a single intercalating agent on kaolin is not as good as that of a composite intercalating agent. This application achieves a better intercalation effect by compounding acetamide and salicylamide to form a composite intercalating agent, which further increases the distance between kaolin sheets, allowing the rubber matrix to enter and bond between the kaolin sheets, forming an organic-inorganic composite material, and enhancing the toughness and elasticity of the rubber material.

[0104] Based on the data from Example 2, Comparative Example 2, and Table 1, it is evident that modifying kaolin with aminosilanes generates amino free radicals during the bonding process with rubber, leading to an odor in the sealing ring. In contrast, methacryloxysilanes do not cause the rubber to produce an odor.

[0105] Based on the data from Example 2, Comparative Example 3, and Table 1, it can be seen that the interfacial bonding between calcined kaolin and rubber is weak, and the rubber molecular chains are prone to slippage and detachment under external force, resulting in weak tensile strength and stress at a given elongation of the rubber material. However, modifying calcined kaolin with methacryloxysilane and a composite intercalating agent significantly improves the dispersibility and compatibility of calcined kaolin in rubber, enhances the interfacial bonding ability between kaolin and rubber, and thus improves the elasticity and toughness of the rubber.

[0106] Based on the data from Example 2, Comparative Example 4, and Table 1, it is evident that excessive carbon black significantly increases the hardness of the rubber, making the material brittle and more prone to fracture under high stress, resulting in poorer resilience. However, the synergistic effect of modified calcined kaolin and N-990 carbon black achieves a better reinforcing effect, maintaining a balance between elasticity and strength in the rubber.

[0107] According to the data in Example 2, Comparative Examples 5-6, and Table 1, by adding modified calcined kaolin, N-990 carbon black, and silica as composite reinforcing agents, an appropriate amount of N-990 carbon black can significantly improve the mechanical properties and abrasion resistance of rubber. The introduction of modified calcined kaolin can reduce the adverse effects on rubber caused by excessive N-990 carbon black addition, and improve the tensile strength and tensile stress of the rubber compound. Silica can optimize the rheological properties of rubber processing. Silica has a higher specific surface area and porosity, which enhances the elasticity and softness of rubber.

[0108] 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 low odor EPDM seal ring characterized in that, By weight parts, prepared from including the following raw materials: Ethylene propylene terpolymer 90-110 parts, modified calcined kaolin 45-55 parts, white carbon black 10-30 parts, N-990 carbon black 30-45 parts, paraffin oil 8-12 parts, stearic acid 0.9-1.5 parts, zinc oxide 5.5-7.5 parts, odor removal agent 0.8-1.2 parts, vulcanizing agent 4-6 parts, crosslinking agent 1.8-2.2 parts; The preparation raw materials of the modified calcined kaolin include calcined kaolin, methacryloyloxysilane and composite intercalation agent, and the weight ratio of the calcined kaolin, the methacryloyloxysilane and the composite intercalation agent is 1: (0.1-0.3): (0.8-1.2); The composite intercalation agent is compounded by acetamide and salicylamide, and the weight ratio of the acetamide and the salicylamide is 1: (0.2-0.4); The preparation method of the modified calcined kaolin is: (1) The calcined kaolin and dimethyl sulfoxide solution are ultrasonically oscillated at 50-60℃ for 18-22h, and then the dimethyl sulfoxide / kaolin composite is obtained after filtration and drying; (2) The composite intercalation agent is dissolved in ethanol solution to form a composite hydrolysis solution, then the dimethyl sulfoxide / kaolin composite is mixed with the composite hydrolysis solution, and is magnetically stirred for 2-4h, washed for 2-3 times, and then the intercalated kaolin is obtained after filtration and drying; (3) The methacryloyloxysilane is dissolved in ethanol solution to form a silane hydrolysis solution, then the silane hydrolysis solution and the intercalated kaolin are placed in a ball mill, the ball mill is vibrated at a frequency of 35-39Hz, and the pretreatment is completed after ball milling for 3-4h, then the modified calcined kaolin is obtained after filtration, washing, drying and crushing.

2. A low odor EPDM seal ring according to claim 1, characterized in that, The methacryloyloxysilane is at least one of γ-methacryloyloxypropyl trimethoxysilane, 3-methacryloyloxypropyl triethoxysilane and 3-methacryloyloxypropyl triisoxysilane.

3. A low odor EPDM seal ring according to claim 1, characterized in that, The vulcanizing agent is at least one of di-tert-butyl peroxide diisopropyl benzene and dicumyl peroxide.

4. A low odor EPDM seal ring according to claim 1, wherein The crosslinking agent is at least one of triallyl isocyanurate, triallyl cyanurate and crosslinking agent CA94-50.

5. A low odor EPDM seal ring according to claim 1, wherein The particle size of the calcined kaolin is 4000-6000 mesh.

6. A process for preparing a low odor EPDM seal ring as claimed in any one of claims 1 to 5, wherein The method comprises the following steps: Firstly, the raw materials are weighed according to the component allocation ratio, and the ethylene propylene terpolymer, the modified calcined kaolin, the white carbon black, the N-990 carbon black, the paraffin oil, the stearic acid, the zinc oxide and the odor removal agent are melt mixed at 140-150℃ to obtain a premix; then, the premix is uniformly mixed with the vulcanizing agent and the crosslinking agent, and is vulcanized and formed by a vulcanizing machine at 150-180℃; finally, the low odor EPDM sealing ring is obtained after edge cutting by a punching equipment.

7. A process for preparing a low odor EPDM seal ring according to claim 6, characterized in that, The vulcanization comprises first vulcanization and second vulcanization, the first vulcanization temperature is 160-180℃, the time is 10-15min, and the pressure is 10-12MPa; the second vulcanization temperature is 150-160℃, the time is 2-3h, and the pressure is 7-9MPa.

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