High-temperature-resistant sealing strip for automobile and preparation method thereof

Abstract

The invention provides a high-temperature-resistant sealing strip for an automobile and a preparation method thereof, and relates to the technical field of rubber sealing elements. The high-temperature-resistant sealing strip for the automobile is prepared from the following materials in parts by weight: 65 to 85 parts of ethylene propylene diene monomer, 32 to 46 parts of nitrile rubber, 20 to 30 parts of diatomite modified basalt fiber, 16 to 20 parts of dual-modified activated aluminum oxide particles, 6 to 8 parts of zinc oxide, 0.5 to 1.5 parts of antioxidant, 1 to 2 parts of anti-aging agent, 1 to 1.6 parts of vulcanizing agent and 0.8 to 1.2 parts of vulcanization accelerator. According to the high-temperature-resistant sealing strip for the automobile, the raw materials and the proportion are meticulously adjusted, and a multi-layer and multifunctional thermal protection system is formed in the sealing strip through the kieselguhr modified basalt fibers and the double-modified activated aluminum oxide particles; the two complements each other and have a synergistic effect, so that the high-temperature resistance of the sealing strip is remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of rubber sealing parts, and in particular to a high temperature resistant sealing strip for automobiles and a preparation method thereof. Background Art

[0002] With the rapid development of the automobile industry, the requirements for the performance stability of automobiles in high temperature environments are getting higher and higher. Among them, automobile sealing strips, as key components to ensure the sealing performance of vehicles, are prone to deformation, aging, and even failure at high temperatures, seriously affecting the safety and comfort of the car. Therefore, the development of a high-temperature resistant and stable performance automobile sealing strip has become a hot topic in current research.

[0003] At present, automotive sealing strips on the market are mainly made of rubber materials, such as ethylene propylene diene monomer (EPDM), nitrile rubber (NBR), etc. Although these rubber materials have certain high temperature resistance, they are still prone to aging and cracking in extreme high temperature environments. In order to improve the high temperature resistance of sealing strips, researchers have tried to add various fillers and additives, such as fibers, ceramic particles, oxides, etc., to enhance the mechanical strength and thermal stability of sealing strips.

[0004] However, existing automotive sealing strips still have deficiencies in high temperature resistance. On the one hand, factors such as the amount, type and dispersibility of fillers and additives have a great influence on the performance of the sealing strips and are difficult to accurately control; on the other hand, the compatibility between fillers and additives and the rubber matrix is ​​poor, which easily leads to problems such as interface peeling and performance degradation. Based on this, the present invention provides a high temperature resistant automotive sealing strip and a preparation method thereof. Summary of the invention

[0005] The purpose of the present invention is to provide a high temperature resistant sealing strip for automobiles and a preparation method thereof, so as to optimize the mechanical properties and high temperature resistant properties of the sealing strip for automobiles.

[0006] On the one hand, the present invention provides a high-temperature resistant sealing strip for automobiles, comprising the following materials in parts by weight: 65-85 parts of EPDM rubber, 32-46 parts of nitrile rubber, 20-30 parts of diatomaceous earth-modified basalt fiber, 16-20 parts of double-modified activated alumina particles, 6-8 parts of zinc oxide, 0.5-1.5 parts of antioxidant, 1-2 parts of antioxidant, 1-1.6 parts of vulcanizer, and 0.8-1.2 parts of vulcanization accelerator.

[0007] Furthermore, the preparation method of the diatomite-modified basalt fiber includes: adding the basalt fiber after ultrasonic cleaning with acetone, the silane coupling agent and the diatomite to a mixed solvent of ethanol and water in a mass ratio of 1:1, mixing them evenly and then performing ultrasonic modification, and then washing with water and ethanol and drying them respectively to obtain the obtained fiber.

[0008] Furthermore, the weight ratio of the basalt fiber, the silane coupling agent and the diatomaceous earth is 5: (0.5-1): (1-1.2).

[0009] Furthermore, the basalt fiber includes two types of fibers of length: 6-8 mm and 20-22 mm, with a diameter of 10-12 μm, and a weight ratio of the two being 1:(3-4).

[0010] Furthermore, the preparation method of the double-modified activated alumina particles includes: adding alumina to concentrated nitric acid and stirring it into a slurry, maintaining it for 30-40 minutes, and after activation, rinsing it with water and drying it to obtain a primary activated alumina; adding the primary activated alumina to an ethanol solution containing 14-16wt% of a silane coupling agent KH560, mixing and ultrasonically reacting for 2-3 hours, drying at 55-65°C for 46-50 hours, and removing excess ethanol to obtain the alumina.

[0011] Furthermore, the dosage ratio of the aluminum oxide to concentrated nitric acid is (2-3) g: (2-3) mL; and the mass ratio of the primary activated aluminum oxide to the silane coupling agent is 100: (4.5-5.5).

[0012] Furthermore, the antioxidant includes one or more of antioxidant 1010 , antioxidant 1135 , antioxidant 168 , and antioxidant 618 .

[0013] Furthermore, the antioxidant includes antioxidant MB and antioxidant 455 in a weight ratio of (1-2):1; the vulcanizing agent is sulfur; and the vulcanization accelerator includes accelerator DM and accelerator ZDC in a weight ratio of (4-5):(1-2).

[0014] On the other hand, the present invention also provides a method for preparing a high temperature resistant sealing strip for an automobile, the steps comprising: (1) Start the internal mixer for preheating, weigh EPDM rubber, nitrile rubber, diatomaceous earth modified basalt fiber, double modified activated alumina particles, and zinc oxide according to the proportion, mix at 95-105°C for 20-30 minutes to obtain a masterbatch; (2) adding antioxidant, anti-aging agent, vulcanizing agent and vulcanization accelerator to the masterbatch according to the proportion, mixing in an open mixer for 5-10 minutes, and then standing at room temperature to obtain a mixed rubber; (3) The mixed rubber is molded and subjected to two vulcanization treatments respectively to obtain a product.

[0015] Furthermore, the two vulcanization treatment steps include: the first vulcanization treatment has a vulcanization temperature of 170-178° C. and a vulcanization time of 5-10 minutes; the second vulcanization treatment has a vulcanization temperature of 180-190° C. and a vulcanization time of 2-3 hours.

[0016] The beneficial effects of the present invention are: (1) The present invention uses EPDM and nitrile rubber as the main materials of the sealing strip by precisely controlling the ratio of various materials. EPDM is a copolymer of ethylene, propylene and a small amount of non-conjugated dienes. This structure makes it have excellent high temperature resistance. With an appropriate amount of nitrile rubber, the stability and durability of the sealing strip at high temperatures can be improved. On this basis, diatomaceous earth modified basalt fiber, double modified activated alumina particles, zinc oxide and other raw materials are added to ensure that the sealing strip has good physical properties and processing properties while maintaining excellent high temperature resistance.

[0017] (2) Diatomaceous earth has an extremely high specific surface area and porosity, and can be used as a carrier to effectively adsorb and fix basalt fibers to form a stable fiber network structure. This structure forms a three-dimensional skeleton inside the sealing strip, which not only enhances the mechanical strength of the sealing strip, but also effectively reduces the thermal deformation and thermal stress concentration of the sealing strip at high temperatures through the poor thermal conductivity and low thermal expansion coefficient of the fiber. In the present invention, the surface properties of basalt fibers are improved by modifying diatomaceous earth and silane coupling agents, the interfacial compatibility between the fibers and the rubber matrix is ​​increased, and the overall performance of the composite material is improved. In addition, when diatomaceous earth is used to modify basalt fibers, its porous structure may also help to enhance the bonding force between the fibers and the sealing strip matrix.

[0018] (3) The basalt fibers in the present invention include fibers of two lengths, 6-8 mm and 20-22 mm. The shorter 6-8 mm fibers can be better dispersed in the rubber matrix, improving the strength and toughness of the rubber, thereby enhancing the tear and fracture resistance of the sealing strip at high temperatures. At the same time, these short fibers can also effectively prevent the excessive stretching and fracture of the rubber molecular chain at high temperatures, further protecting the integrity of the sealing strip. The longer 20-22 mm fibers play the role of bridges and skeletons. They form a stable network structure in the rubber matrix, which can resist the softening and deformation of the rubber caused by high temperatures. The addition of long fibers also improves the creep resistance of the rubber, so that the sealing strip can still maintain its original shape and sealing effect under the action of high temperature for a long time. By adding these two lengths of fibers, the sealing strip can not only maintain a stable shape and size under high temperature environment, but also effectively prevent rubber aging and performance degradation caused by high temperature. The design of this composite reinforcement structure enables the sealing strip to still exert excellent sealing performance under high temperature conditions, thereby extending the service life of the sealing strip and improving its reliability.

[0019] (4) The present invention enhances the surface activity and dispersibility of activated alumina through concentrated nitric acid activation and dual modification with silane coupling agent KH560, and enhances the interaction between activated alumina and rubber matrix, which is beneficial to improving the high temperature stability and durability of the sealing strip. After dual modification, the surface properties of activated alumina are improved, and it not only has higher thermal stability and chemical stability, but also has excellent adsorption capacity and catalytic performance. These particles can be evenly dispersed in the sealing strip material to form a thermal barrier layer, effectively reflect and absorb heat, and reduce the temperature inside the sealing strip.

[0020] (5) In the present invention, the diatomite-modified basalt fiber and the double-modified activated alumina particles work together inside the sealing strip to form a multi-level, multifunctional thermal protection system. The basalt fiber skeleton provides structural support for the sealing strip, while the activated alumina particles enhance the thermal barrier capacity of the sealing strip through their excellent thermal stability and adsorption properties. The two complement each other and work synergistically to significantly improve the high temperature resistance of the sealing strip.

[0021] (6) In the present invention, two vulcanization treatments are used to improve the high temperature resistance of the sealing strip; the first vulcanization treatment is carried out at a lower temperature and time to initially shape the sealing strip; the second vulcanization treatment is carried out at a higher temperature and longer time to fully cross-link the rubber molecular chains to form a stable network structure, thereby improving the high temperature stability and durability of the sealing strip. DETAILED DESCRIPTION

[0022] The technical scheme of the present invention is described clearly and completely below. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. It should be noted that the following raw materials are all commercially available.

[0023] Example 1

[0024] The present embodiment provides a high temperature resistant sealing strip for automobiles, comprising the following materials in parts by weight: 75 parts of EPDM rubber, 39 parts of nitrile rubber, 25 parts of diatomaceous earth modified basalt fiber, 18 parts of double modified activated alumina particles, 7 parts of zinc oxide, 1 part of antioxidant, 1.5 parts of anti-aging agent, 1.3 parts of vulcanizing agent, and 1 part of vulcanization accelerator; The preparation method of diatomite-modified basalt fiber includes: adding basalt fiber, silane coupling agent and diatomite after ultrasonic cleaning with acetone in a weight ratio of 5:0.7:1.1 to a mixed solvent of ethanol and water in a mass ratio of 1:1, mixing evenly and then ultrasonically modifying, washing with water and ethanol three times respectively after 30 minutes, and drying to obtain the basalt fiber. The basalt fiber includes two lengths of 7mm and 21mm in a weight ratio of 1:3.5, with a diameter of 11μm; the diameter of the alumina particles is 30μm, and the other embodiments are the same as the comparative examples.

[0025] The preparation method of the double-modified activated alumina particles includes: adding alumina to concentrated nitric acid and stirring it into a slurry, maintaining it for 35 minutes, rinsing it with water after activation and drying it to obtain a primary activated alumina; adding the primary activated alumina to an ethanol solution containing 15wt% of the silane coupling agent KH560, mixing and ultrasonically reacting for 2.5 hours, drying at 60°C for 48 hours, and removing excess ethanol. The dosage ratio of the alumina to the concentrated nitric acid is 1g:1mL; the mass ratio of the primary activated alumina to the silane coupling agent is 100:5; The antioxidant is antioxidant 1010; the antioxidant includes antioxidant MB and antioxidant 455 in a weight ratio of 1.5:1; the vulcanizing agent is sulfur; and the vulcanization accelerator includes accelerator DM and accelerator ZDC in a weight ratio of 4.5:1.5.

[0026] The method for preparing the high temperature resistant sealing strip for automobiles in this embodiment comprises the following steps: (1) Start the internal mixer for preheating, weigh EPDM rubber, nitrile rubber, diatomaceous earth modified basalt fiber, double modified activated alumina particles, and zinc oxide according to the proportion, mix at 100 ° C for 25 minutes to obtain a masterbatch; (2) adding an antioxidant, an anti-aging agent, a vulcanizing agent, and a vulcanization accelerator to the masterbatch according to a proportion, mixing the mixture in an open mixer for 7 minutes, and then standing the mixture at room temperature to obtain a mixed rubber; (3) The rubber mixture is molded and subjected to two vulcanization treatments, wherein the first vulcanization treatment is performed at a vulcanization temperature of 174°C and a vulcanization time of 7 minutes; and the second vulcanization treatment is performed at a vulcanization temperature of 185°C and a vulcanization time of 2.5 hours.

[0027] Example 2

[0028] The present embodiment provides a high temperature resistant sealing strip for automobiles, comprising the following materials in parts by weight: 70 parts of EPDM rubber, 36 parts of nitrile rubber, 24 parts of diatomaceous earth modified basalt fiber, 17 parts of double modified activated alumina particles, 6 parts of zinc oxide, 1.2 parts of antioxidant, 1.2 parts of anti-aging agent, 1.4 parts of vulcanizing agent, and 1.0 parts of vulcanization accelerator; The preparation method of diatomite-modified basalt fiber includes: adding basalt fiber, silane coupling agent and diatomite after ultrasonic cleaning with acetone in a weight ratio of 5:0.5:1 to a mixed solvent of ethanol and water in a mass ratio of 1:1, mixing evenly and then ultrasonically modifying, washing with water and ethanol three times respectively after 30 minutes, and drying to obtain the basalt fiber. The basalt fiber includes two lengths of 6mm and 20mm in a weight ratio of 1:3, with a diameter of 10μm; The preparation method of the double-modified activated alumina particles includes: adding alumina to concentrated nitric acid and stirring it into a slurry, maintaining it for 30 minutes, rinsing it with water after activation and drying it to obtain a primary activated alumina; adding the primary activated alumina to an ethanol solution containing 14wt% of the silane coupling agent KH560, mixing and ultrasonically reacting it for 2 hours, drying it at 65°C for 46 hours, and removing the excess ethanol. The dosage ratio of the alumina to the concentrated nitric acid is 2g:3mL; the mass ratio of the primary activated alumina to the silane coupling agent is 100:4.5; The antioxidant is antioxidant 1135; the antioxidant includes antioxidant MB and antioxidant 455 in a weight ratio of 1:1; the vulcanizing agent is sulfur; and the vulcanization accelerator includes accelerator DM and accelerator ZDC in a weight ratio of 4:1.

[0029] The method for preparing the high temperature resistant sealing strip for automobiles in this embodiment comprises the following steps: (1) Start the internal mixer for preheating, weigh EPDM rubber, nitrile rubber, diatomaceous earth modified basalt fiber, double modified activated alumina particles, and zinc oxide according to the proportion, mix them at 95°C for 20 minutes to obtain a masterbatch; (2) adding an antioxidant, an anti-aging agent, a vulcanizing agent, and a vulcanization accelerator to the masterbatch according to a proportion, mixing the mixture in an open mixer for 8 minutes, and then standing the mixture at room temperature to obtain a mixed rubber; (3) The rubber mixture is molded and subjected to two vulcanization treatments, wherein the first vulcanization treatment is performed at a vulcanization temperature of 172°C and a vulcanization time of 8 min; and the second vulcanization treatment is performed at a vulcanization temperature of 185°C and a vulcanization time of 2 h.

[0030] Example 3

[0031] The present embodiment provides a high temperature resistant sealing strip for automobiles, comprising the following materials in parts by weight: 80 parts of EPDM rubber, 40 parts of nitrile rubber, 26 parts of diatomaceous earth modified basalt fiber, 18 parts of double modified activated alumina particles, 8 parts of zinc oxide, 1.5 parts of antioxidant, 2 parts of anti-aging agent, 1.6 parts of vulcanizing agent, and 1.2 parts of vulcanization accelerator; The preparation method of diatomite-modified basalt fiber includes: adding basalt fiber, silane coupling agent and diatomite after ultrasonic cleaning with acetone in a weight ratio of 5:1:1.2 to a mixed solvent of ethanol and water in a mass ratio of 1:1, mixing evenly and then ultrasonically modifying, washing with water and ethanol three times respectively after 30 minutes, and drying to obtain the basalt fiber. The basalt fiber includes two lengths of 8mm and 22mm in a weight ratio of 1:3, with a diameter of 12μm; The preparation method of the double-modified activated alumina particles includes: adding alumina to concentrated nitric acid and stirring it into a slurry, maintaining it for 40 minutes, rinsing it with water after activation and drying it to obtain a primary activated alumina; adding the primary activated alumina to an ethanol solution containing 16wt% of the silane coupling agent KH560, mixing and ultrasonically reacting for 3 hours, drying it at 65°C for 50 hours, and removing excess ethanol. The dosage ratio of the alumina to the concentrated nitric acid is 3g:2mL; the mass ratio of the primary activated alumina to the silane coupling agent is 100:5.5; The antioxidant is one or more of antioxidant 168; the antioxidant includes antioxidant MB and antioxidant 455 in a weight ratio of 2:1; the vulcanizing agent is sulfur; and the vulcanization accelerator is accelerator DM and accelerator ZDC in a mass ratio of 5:2.

[0032] The method for preparing the high temperature resistant sealing strip for automobiles in this embodiment comprises the following steps: (1) Start the internal mixer for preheating, weigh EPDM rubber, nitrile rubber, diatomaceous earth modified basalt fiber, double modified activated alumina particles, and zinc oxide according to the proportion, mix them at 105°C for 20 minutes to obtain a masterbatch; (2) adding antioxidant, anti-aging agent, vulcanizing agent and vulcanization accelerator to the masterbatch according to the proportion, mixing in an open mixer for 10 minutes, and then standing at room temperature to obtain a mixed rubber; (3) The rubber mixture is molded and subjected to two vulcanization treatments, wherein the first vulcanization treatment is performed at a vulcanization temperature of 178°C and a vulcanization time of 6 min; the second vulcanization treatment is performed at a vulcanization temperature of 190°C and a vulcanization time of 2 h.

[0033] Example 4

[0034] The present embodiment provides a high temperature resistant sealing strip for automobiles, comprising the following materials in parts by weight: 85 parts of EPDM rubber, 32 parts of nitrile rubber, 30 parts of diatomaceous earth modified basalt fiber, 16 parts of double modified activated alumina particles, 8 parts of zinc oxide, 0.5 parts of antioxidant, 2 parts of anti-aging agent, 1 part of vulcanizing agent, and 1.2 parts of vulcanization accelerator; The preparation method of diatomite-modified basalt fiber includes: adding basalt fiber, silane coupling agent and diatomite after ultrasonic cleaning with acetone in a weight ratio of 5:1:1.2 to a mixed solvent of ethanol and water in a mass ratio of 1:1, mixing evenly and then ultrasonically modifying, washing with water and ethanol three times respectively after 30 minutes, and drying to obtain the basalt fiber. The basalt fiber includes two lengths of 8mm and 20mm in a weight ratio of 1:3, with a diameter of 12μm; The preparation method of the double-modified activated alumina particles includes: adding alumina to concentrated nitric acid and stirring it into a slurry, maintaining it for 30 minutes, rinsing it with water after activation and drying it to obtain a primary activated alumina; adding the primary activated alumina to an ethanol solution containing 16wt% of a silane coupling agent KH560, mixing and ultrasonically reacting it for 3 hours, drying it at 55°C for 50 hours, and removing excess ethanol to obtain the obtained alumina particles. The dosage ratio of the alumina to the concentrated nitric acid is (3) g: (2) mL; the mass ratio of the primary activated alumina to the silane coupling agent is 100: (4.5); The antioxidant is antioxidant 618; the antioxidant includes antioxidant MB and antioxidant 455 in a weight ratio of 2:1; the vulcanizing agent is sulfur; and the vulcanization accelerator includes accelerator DM and accelerator ZDC in a weight ratio of 5:2.

[0035] The method for preparing the high temperature resistant sealing strip for automobiles in this embodiment comprises the following steps: (1) Start the internal mixer for preheating, weigh EPDM rubber, nitrile rubber, diatomaceous earth modified basalt fiber, double modified activated alumina particles, and zinc oxide according to the proportion, mix at 100 ° C for 30 minutes to obtain a masterbatch; (2) adding antioxidant, anti-aging agent, vulcanizing agent and vulcanization accelerator to the masterbatch according to the proportion, mixing in an open mixer for 10 minutes, and then standing at room temperature to obtain a mixed rubber; (3) The rubber mixture is molded and subjected to two vulcanization treatments, wherein the first vulcanization treatment is performed at a vulcanization temperature of 170°C and a vulcanization time of 10 min; and the second vulcanization treatment is performed at a vulcanization temperature of 190°C and a vulcanization time of 2 h.

[0036] Comparative Example 1 The present embodiment provides a high temperature resistant sealing strip for automobiles, comprising the following materials in parts by weight: 75 parts of EPDM rubber, 39 parts of nitrile rubber, 25 parts of silica-modified basalt fiber, 18 parts of double-modified activated alumina particles, 7 parts of zinc oxide, 1 part of antioxidant, 1.5 parts of anti-aging agent, 1.3 parts of vulcanizing agent, and 1 part of vulcanization accelerator; The preparation method of silica-modified basalt fiber includes: adding basalt fiber, silane coupling agent and silica after ultrasonic cleaning with acetone in a weight ratio of 5:0.7:1.1 to a mixed solvent of ethanol and water in a mass ratio of 1:1, mixing evenly and then ultrasonically modifying, washing with water and ethanol three times respectively after 30 minutes, and drying to obtain the basalt fiber. The basalt fiber includes two lengths of 7mm and 21mm in a weight ratio of 1:3.5, with a diameter of 11μm; The preparation method of the double-modified activated alumina particles includes: adding alumina to concentrated nitric acid and stirring it into a slurry, maintaining it for 35 minutes, rinsing it with water after activation and drying it to obtain a primary activated alumina; adding the primary activated alumina to an ethanol solution containing 15wt% of the silane coupling agent KH560, mixing and ultrasonically reacting for 2.5 hours, drying at 60°C for 48 hours, and removing excess ethanol. The dosage ratio of the alumina to the concentrated nitric acid is 1g:1mL; the mass ratio of the primary activated alumina to the silane coupling agent is 100:5; The antioxidant is antioxidant 1010; the antioxidant includes antioxidant MB and antioxidant 455 in a weight ratio of 1.5:1; the vulcanizing agent is sulfur; and the vulcanization accelerator includes accelerator DM and accelerator ZDC in a weight ratio of 4.5:1.5.

[0037] The method for preparing the high temperature resistant sealing strip for automobiles in this embodiment comprises the following steps: (1) Start the internal mixer for preheating, weigh EPDM rubber, nitrile rubber, silica-modified basalt fiber, double-modified activated alumina particles, and zinc oxide according to the ratio, and mix them at 100° C. for 25 minutes to obtain a masterbatch; (2) adding an antioxidant, an anti-aging agent, a vulcanizing agent, and a vulcanization accelerator to the masterbatch according to a proportion, mixing the mixture in an open mixer for 7 minutes, and then standing the mixture at room temperature to obtain a mixed rubber; (3) The rubber mixture is molded and subjected to two vulcanization treatments, wherein the first vulcanization treatment is performed at a vulcanization temperature of 174°C and a vulcanization time of 7 minutes; and the second vulcanization treatment is performed at a vulcanization temperature of 185°C and a vulcanization time of 2.5 hours.

[0038] Comparative Example 2 The present embodiment provides a high temperature resistant sealing strip for automobiles, comprising the following materials in parts by weight: 75 parts of EPDM rubber, 39 parts of nitrile rubber, 25 parts of diatomaceous earth modified basalt fiber, 18 parts of double modified activated alumina particles, 7 parts of zinc oxide, 1 part of antioxidant, 1.5 parts of anti-aging agent, 1.3 parts of vulcanizing agent, and 1 part of vulcanization accelerator; The preparation method of diatomite-modified basalt fiber includes: adding basalt fiber, silane coupling agent and diatomite after ultrasonic cleaning with acetone in a weight ratio of 5:0.7:1.1 to a mixed solvent of ethanol and water in a mass ratio of 1:1, mixing evenly and then performing ultrasonic modification, washing with water and ethanol three times respectively after 30 minutes, and drying to obtain the basalt fiber. The basalt fiber has a length of 7mm and a diameter of 11μm; The preparation method of the double-modified activated alumina particles includes: adding alumina to concentrated nitric acid and stirring it into a slurry, maintaining it for 35 minutes, rinsing it with water after activation and drying it to obtain a primary activated alumina; adding the primary activated alumina to an ethanol solution containing 15wt% of the silane coupling agent KH560, mixing and ultrasonically reacting for 2.5 hours, drying at 60°C for 48 hours, and removing excess ethanol. The dosage ratio of the alumina to the concentrated nitric acid is 1g:1mL; the mass ratio of the primary activated alumina to the silane coupling agent is 100:5; The antioxidant is antioxidant 1010; the antioxidant includes antioxidant MB and antioxidant 455 in a weight ratio of 1.5:1; the vulcanizing agent is sulfur; and the vulcanization accelerator includes accelerator DM and accelerator ZDC in a weight ratio of 4.5:1.5.

[0039] The method for preparing the high temperature resistant sealing strip for automobiles in this embodiment comprises the following steps: (1) Start the internal mixer for preheating, weigh EPDM rubber, nitrile rubber, diatomaceous earth modified basalt fiber, double modified activated alumina particles, and zinc oxide according to the proportion, mix at 100 ° C for 25 minutes to obtain a masterbatch; (2) adding an antioxidant, an anti-aging agent, a vulcanizing agent, and a vulcanization accelerator to the masterbatch according to a proportion, mixing the mixture in an open mixer for 7 minutes, and then standing the mixture at room temperature to obtain a mixed rubber; (3) The rubber mixture is molded and subjected to two vulcanization treatments, wherein the first vulcanization treatment is performed at a vulcanization temperature of 174°C and a vulcanization time of 7 minutes; and the second vulcanization treatment is performed at a vulcanization temperature of 185°C and a vulcanization time of 2.5 hours.

[0040] Comparative Example 3 The present embodiment provides a high temperature resistant sealing strip for automobiles, comprising the following materials in parts by weight: 75 parts of EPDM rubber, 39 parts of nitrile rubber, 25 parts of diatomaceous earth modified basalt fiber, 18 parts of double modified activated alumina particles, 7 parts of zinc oxide, 1 part of antioxidant, 1.5 parts of anti-aging agent, 1.3 parts of vulcanizing agent, and 1 part of vulcanization accelerator; The preparation method of diatomite-modified basalt fiber includes: adding basalt fiber, silane coupling agent and diatomite after ultrasonic cleaning with acetone in a weight ratio of 5:0.7:1.1 to a mixed solvent of ethanol and water in a mass ratio of 1:1, mixing evenly and then performing ultrasonic modification, washing with water and ethanol three times respectively after 30 minutes, and drying to obtain the basalt fiber. The basalt fiber has a length of 21 mm and a diameter of 11 μm; The preparation method of the double-modified activated alumina particles includes: adding alumina to concentrated nitric acid and stirring it into a slurry, maintaining it for 35 minutes, rinsing it with water after activation and drying it to obtain a primary activated alumina; adding the primary activated alumina to an ethanol solution containing 15wt% of the silane coupling agent KH560, mixing and ultrasonically reacting for 2.5 hours, drying at 60°C for 48 hours, and removing excess ethanol. The dosage ratio of the alumina to the concentrated nitric acid is 1g:1mL; the mass ratio of the primary activated alumina to the silane coupling agent is 100:5; The antioxidant is antioxidant 1010; the antioxidant includes antioxidant MB and antioxidant 455 in a weight ratio of 1.5:1; the vulcanizing agent is sulfur; and the vulcanization accelerator includes accelerator DM and accelerator ZDC in a weight ratio of 4.5:1.5.

[0041] The method for preparing the high temperature resistant sealing strip for automobiles in this embodiment comprises the following steps: (1) Start the internal mixer for preheating, weigh EPDM rubber, nitrile rubber, diatomaceous earth modified basalt fiber, double modified activated alumina particles, and zinc oxide according to the proportion, mix at 100 ° C for 25 minutes to obtain a masterbatch; (2) adding an antioxidant, an anti-aging agent, a vulcanizing agent, and a vulcanization accelerator to the masterbatch according to a proportion, mixing the mixture in an open mixer for 7 minutes, and then standing the mixture at room temperature to obtain a mixed rubber; (3) The rubber mixture is molded and subjected to two vulcanization treatments, wherein the first vulcanization treatment is performed at a vulcanization temperature of 174°C and a vulcanization time of 7 minutes; and the second vulcanization treatment is performed at a vulcanization temperature of 185°C and a vulcanization time of 2.5 hours.

[0042] Comparative Example 4 The present embodiment provides a high temperature resistant sealing strip for automobiles, comprising the following materials in parts by weight: 75 parts of EPDM rubber, 39 parts of nitrile rubber, 25 parts of basalt fiber, 18 parts of double modified activated alumina particles, 7 parts of zinc oxide, 1 part of antioxidant, 1.5 parts of anti-aging agent, 1.3 parts of vulcanizing agent, and 1 part of vulcanization accelerator; The basalt fibers include two lengths of 7 mm and 21 mm in a weight ratio of 1:3.5, and a diameter of 11 μm; The preparation method of the double-modified activated alumina particles includes: adding alumina to concentrated nitric acid and stirring it into a slurry, maintaining it for 35 minutes, rinsing it with water after activation and drying it to obtain a primary activated alumina; adding the primary activated alumina to an ethanol solution containing 15wt% of the silane coupling agent KH560, mixing and ultrasonically reacting for 2.5 hours, drying at 60°C for 48 hours, and removing excess ethanol. The dosage ratio of the alumina to the concentrated nitric acid is 1g:1mL; the mass ratio of the primary activated alumina to the silane coupling agent is 100:5; The antioxidant is antioxidant 1010; the antioxidant includes antioxidant MB and antioxidant 455 in a weight ratio of 1.5:1; the vulcanizing agent is sulfur; and the vulcanization accelerator includes accelerator DM and accelerator ZDC in a weight ratio of 4.5:1.5.

[0043] The method for preparing the high temperature resistant sealing strip for automobiles in this embodiment comprises the following steps: (1) Start the internal mixer for preheating, weigh EPDM rubber, nitrile rubber, diatomaceous earth modified basalt fiber, double modified activated alumina particles, and zinc oxide according to the proportion, mix at 100 ° C for 25 minutes to obtain a masterbatch; (2) adding an antioxidant, an anti-aging agent, a vulcanizing agent, and a vulcanization accelerator to the masterbatch according to a proportion, mixing the mixture in an open mixer for 7 minutes, and then standing the mixture at room temperature to obtain a mixed rubber; (3) The rubber mixture is molded and subjected to two vulcanization treatments, wherein the first vulcanization treatment is performed at a vulcanization temperature of 174°C and a vulcanization time of 7 minutes; and the second vulcanization treatment is performed at a vulcanization temperature of 185°C and a vulcanization time of 2.5 hours.

[0044] Comparative Example 5 The present embodiment provides a high temperature resistant sealing strip for automobiles, comprising the following materials in parts by weight: 75 parts of EPDM rubber, 39 parts of nitrile rubber, 25 parts of diatomaceous earth modified basalt fiber, 18 parts of modified activated alumina particles, 7 parts of zinc oxide, 1 part of antioxidant, 1.5 parts of anti-aging agent, 1.3 parts of vulcanizing agent, and 1 part of vulcanization accelerator; The preparation method of diatomite-modified basalt fiber includes: adding basalt fiber, silane coupling agent and diatomite after ultrasonic cleaning with acetone in a weight ratio of 5:0.7:1.1 to a mixed solvent of ethanol and water in a mass ratio of 1:1, mixing evenly and then ultrasonically modifying, washing with water and ethanol three times respectively after 30 minutes, and drying to obtain the basalt fiber. The basalt fiber includes two lengths of 7mm and 21mm in a weight ratio of 1:3.5, with a diameter of 11μm; The preparation method of the modified activated alumina particles comprises: adding alumina to concentrated nitric acid and stirring to form a slurry, maintaining for 35 minutes, and rinsing with water and drying after activation. The ratio of the amount of alumina to concentrated nitric acid is 1g:1mL; The antioxidant is antioxidant 1010; the antioxidant includes antioxidant MB and antioxidant 455 in a weight ratio of 1.5:1; the vulcanizing agent is sulfur; and the vulcanization accelerator includes accelerator DM and accelerator ZDC in a weight ratio of 4.5:1.5.

[0045] The method for preparing the high temperature resistant sealing strip for automobiles in this embodiment comprises the following steps: (1) Start the internal mixer for preheating, weigh EPDM rubber, nitrile rubber, diatomaceous earth modified basalt fiber, modified activated alumina particles, and zinc oxide according to the ratio, and mix them at 100°C for 25 minutes to obtain a masterbatch; (2) adding an antioxidant, an anti-aging agent, a vulcanizing agent, and a vulcanization accelerator to the masterbatch according to a proportion, mixing the mixture in an open mixer for 7 minutes, and then standing the mixture at room temperature to obtain a mixed rubber; (3) The rubber mixture is molded and subjected to two vulcanization treatments, wherein the first vulcanization treatment is performed at a vulcanization temperature of 174°C and a vulcanization time of 7 minutes; and the second vulcanization treatment is performed at a vulcanization temperature of 185°C and a vulcanization time of 2.5 hours.

[0046] Comparative Example 6 The present embodiment provides a high temperature resistant sealing strip for automobiles, comprising the following materials in parts by weight: 75 parts of EPDM rubber, 39 parts of nitrile rubber, 25 parts of diatomaceous earth modified basalt fiber, 18 parts of modified activated alumina particles, 7 parts of zinc oxide, 1 part of antioxidant, 1.5 parts of anti-aging agent, 1.3 parts of vulcanizing agent, and 1 part of vulcanization accelerator; The preparation method of diatomite-modified basalt fiber includes: adding basalt fiber, silane coupling agent and diatomite after ultrasonic cleaning with acetone in a weight ratio of 5:0.7:1.1 to a mixed solvent of ethanol and water in a mass ratio of 1:1, mixing evenly and then ultrasonically modifying, washing with water and ethanol three times respectively after 30 minutes, and drying to obtain the basalt fiber. The basalt fiber includes two lengths of 7mm and 21mm in a weight ratio of 1:3.5, with a diameter of 11μm; The preparation method of the modified activated alumina particles comprises: adding alumina to an ethanol solution containing 15wt% of a silane coupling agent KH560, mixing and ultrasonically reacting for 2.5h, drying at 60°C for 48h, and removing excess ethanol. The mass ratio of the alumina to the silane coupling agent is 100:5; The antioxidant is antioxidant 1010; the antioxidant includes antioxidant MB and antioxidant 455 in a weight ratio of 1.5:1; the vulcanizing agent is sulfur; and the vulcanization accelerator includes accelerator DM and accelerator ZDC in a weight ratio of 4.5:1.5.

[0047] The method for preparing the high temperature resistant sealing strip for automobiles in this embodiment comprises the following steps: (1) Start the internal mixer for preheating, weigh EPDM rubber, nitrile rubber, diatomaceous earth modified basalt fiber, double modified activated alumina particles, and zinc oxide according to the proportion, mix at 100 ° C for 25 minutes to obtain a masterbatch; (2) adding an antioxidant, an anti-aging agent, a vulcanizing agent, and a vulcanization accelerator to the masterbatch according to a proportion, mixing the mixture in an open mixer for 7 minutes, and then standing the mixture at room temperature to obtain a mixed rubber; (3) The rubber mixture is molded and subjected to two vulcanization treatments, wherein the first vulcanization treatment is performed at a vulcanization temperature of 174°C and a vulcanization time of 7 minutes; and the second vulcanization treatment is performed at a vulcanization temperature of 185°C and a vulcanization time of 2.5 hours.

[0048] Comparative Example 7 The present embodiment provides a high temperature resistant sealing strip for automobiles, comprising the following materials in parts by weight: 75 parts of EPDM rubber, 39 parts of nitrile rubber, 25 parts of diatomaceous earth modified basalt fiber, 18 parts of aluminum oxide particles, 7 parts of zinc oxide, 1 part of antioxidant, 1.5 parts of anti-aging agent, 1.3 parts of vulcanizing agent, and 1 part of vulcanization accelerator; The preparation method of diatomite-modified basalt fiber includes: adding basalt fiber, silane coupling agent and diatomite after ultrasonic cleaning with acetone in a weight ratio of 5:0.7:1.1 to a mixed solvent of ethanol and water in a mass ratio of 1:1, mixing evenly and then ultrasonically modifying, washing with water and ethanol three times respectively after 30 minutes, and drying to obtain the basalt fiber. The basalt fiber includes two lengths of 7mm and 21mm in a weight ratio of 1:3.5, with a diameter of 11μm; The antioxidant is antioxidant 1010; the antioxidant includes antioxidant MB and antioxidant 455 in a weight ratio of 1.5:1; the vulcanizing agent is sulfur; and the vulcanization accelerator includes accelerator DM and accelerator ZDC in a weight ratio of 4.5:1.5.

[0049] The method for preparing the high temperature resistant sealing strip for automobiles in this embodiment comprises the following steps: (1) Start the internal mixer for preheating, weigh EPDM rubber, nitrile rubber, diatomaceous earth modified basalt fiber, double modified activated alumina particles, and zinc oxide according to the proportion, mix at 100 ° C for 25 minutes to obtain a masterbatch; (2) adding an antioxidant, an anti-aging agent, a vulcanizing agent, and a vulcanization accelerator to the masterbatch according to a proportion, mixing the mixture in an open mixer for 7 minutes, and then standing the mixture at room temperature to obtain a mixed rubber; (3) The rubber mixture is molded and subjected to two vulcanization treatments, wherein the first vulcanization treatment is performed at a vulcanization temperature of 174°C and a vulcanization time of 7 minutes; and the second vulcanization treatment is performed at a vulcanization temperature of 185°C and a vulcanization time of 2.5 hours.

[0050] Test Example 1: The performance of the high temperature resistant sealing strips prepared in the above-mentioned Examples 1-4 and Comparative Examples 1-7 was investigated, wherein the hot air aging performance test was conducted in accordance with the GB / T 3512-2014 method, and a Type 1 air aging chamber was used to test the mechanical property change rate of the sample under hot air aging conditions (aging at 125°C for 168h). The performance test results are shown in Table 1 below:

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. Those skilled in the art should understand that the present invention can still be modified or replaced by equivalents. All technical solutions and improvements that do not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A high temperature resistant sealing strip for automobiles, characterized in that: It contains the following materials in parts by weight: 65-85 parts of EPDM rubber, 32-46 parts of nitrile rubber, 20-30 parts of diatomaceous earth modified basalt fiber, 16-20 parts of double modified activated alumina particles, 6-8 parts of zinc oxide, 0.5-1.5 parts of antioxidant, 1-2 parts of antioxidant, 1-1.6 parts of vulcanizer, and 0.8-1.2 parts of vulcanization accelerator.

2. A high temperature resistant sealing strip for automobiles according to claim 1, characterized in that: The preparation method of diatomite-modified basalt fiber comprises: adding basalt fiber ultrasonically cleaned with acetone, a silane coupling agent and diatomite into a mixed solvent of ethanol and water in a mass ratio of 1:1, mixing evenly and then performing ultrasonic modification, and then washing with water and ethanol and drying respectively to obtain the fiber.

3. A high temperature resistant sealing strip for automobiles according to claim 2, characterized in that: The weight ratio of the basalt fiber, the silane coupling agent and the diatomaceous earth is 5: (0.5-1): (1-1.2).

4. A high temperature resistant sealing strip for automobiles according to claim 2, characterized in that: The basalt fibers include fibers of two lengths, 6-8 mm and 20-22 mm, with a diameter of 10-12 μm, and a weight ratio of the two being 1:(3-4).

5. The high temperature resistant sealing strip for automobile according to claim 1, characterized in that: The preparation method of the double-modified activated alumina particles comprises: adding alumina to concentrated nitric acid and stirring it into a slurry, maintaining it for 30-40 minutes, and after activation, washing it with water and drying it to obtain primary activated alumina; adding the primary activated alumina to an ethanol solution containing 14-16wt% of a silane coupling agent KH560, mixing and ultrasonically reacting it for 2-3h, drying it at 55-65°C for 46-50h, and removing excess ethanol to obtain the particles.

6. A high temperature resistant sealing strip for automobiles according to claim 5, characterized in that: The dosage ratio of the aluminum oxide to concentrated nitric acid is (2-3) g: (2-3) mL; the mass ratio of the primary activated aluminum oxide to the silane coupling agent is 100: (4.5-5.5).

7. The high temperature resistant sealing strip for automobile according to claim 1, characterized in that: The antioxidant includes one or more of antioxidant 1010 , antioxidant 1135 , antioxidant 168 , and antioxidant 618 .

8. The high temperature resistant sealing strip for automobile according to claim 1, characterized in that: The antioxidant includes antioxidant MB and antioxidant 455 in a weight ratio of (1-2):1; the vulcanizing agent is sulfur; and the vulcanization accelerator includes accelerator DM and accelerator ZDC in a weight ratio of (4-5):(1-2).

9. A method for preparing a high temperature resistant sealing strip for automobiles according to any one of claims 1 to 8, characterized in that the steps include: (1) Start the internal mixer for preheating, weigh EPDM rubber, nitrile rubber, diatomaceous earth modified basalt fiber, double modified activated alumina particles, and zinc oxide according to the proportion, mix at 95-105°C for 20-30 minutes to obtain a masterbatch; (2) adding antioxidant, anti-aging agent, vulcanizing agent and vulcanization accelerator to the masterbatch according to the proportion, mixing in an open mixer for 5-10 minutes, and then standing at room temperature to obtain a mixed rubber; (3) The rubber mixture is molded and subjected to two vulcanization treatments respectively to obtain a product.

10. The preparation method according to claim 9, characterized in that: The two vulcanization steps include: the first vulcanization temperature is 170-178° C., and the vulcanization time is 5-10 minutes; the second vulcanization temperature is 180-190° C., and the vulcanization time is 2-3 hours.

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