A polymer sealing ring and its preparation method

Abstract

This application discloses a polymer sealing ring and its preparation method, relating to the field of polymer materials technology. The raw materials, by mass percentage, include 30-50% fluorinated modified silicone rubber, 15-25% fluororubber, 7.2-16.4% hybrid silica, 2.5-6% hydroxyl silicone oil, 8-11% plasma-modified alumina, 4-8% carbon black, 0.8-1.4% palm wax, 0.8-1.4% internal release agent, 1-2% vulcanizing agent, 3-5% triallyl isocyanurate, and 0.5-1% antioxidant. This application prepares fluorinated modified silicone rubber by grafting C2-18-perfluoroalkyl iodoethane onto the side chains of silicone rubber, effectively improving the low-temperature resistance of silicone rubber and successfully suppressing the low-temperature crystallization phenomenon of methyl vinyl silicone rubber. Using a blend of fluororubber and fluorinated modified silicone rubber as the sealing ring matrix exhibits good performance at both high and low temperatures, effectively expanding the service temperature range of the sealing ring material.

Description

Technical Field

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

[0002] A sealing ring is a widely used elastic ring-shaped component in industry and daily life, primarily used to prevent fluid or gas leakage and ensure the sealing performance of equipment and systems. Polymer sealing rings are made of high-molecular polymers, including rubber, silicone rubber, fluororubber, and polytetrafluoroethylene (PTFE). Due to their unique properties, such as good elasticity, wear resistance, and chemical corrosion resistance, polymer materials are ideal for manufacturing sealing rings. Compared to traditional metal seals, polymer sealing rings offer advantages such as light weight, low cost, and ease of processing. These characteristics make polymer sealing rings indispensable in modern industry, serving as key components for ensuring safe equipment operation and improving production efficiency.

[0003] However, polymer sealing rings often face a series of technical challenges under different temperature conditions. For example, due to temperature and pressure variations in high-temperature environments, conventional rubber sealing rings are prone to aging, deformation, and hardening, leading to decreased sealing performance or even failure. With continuous technological advancements, the formulation and manufacturing technology of polymer sealing ring materials have undergone significant evolution, especially in the use of fillers and additives. These improvements have also significantly enhanced the temperature resistance of polymer sealing ring materials.

[0004] For related technologies, please refer to Chinese invention patent CN116751414B, which discloses a high-temperature resistant rubber sealing ring and its preparation method. The raw materials include, by weight, 100 parts rubber, 4-9 parts activator, 1-2 parts co-activator, 1-4 parts chemical antioxidant, 0.5-1.5 parts physical antioxidant, 70-90 parts reinforcing agent, 3-8 parts plasticizer, 10-15 parts hydrogenated dimer fatty acid, 4-10 parts ferric chloride, 2-5 parts thioctic acid, 3-5 parts crosslinking agent DCP, and 1-2 parts accelerator DM.

[0005] Regarding the aforementioned technologies, the inventors believe that although adding fillers and additives can effectively improve the high-temperature resistance of polymer sealing rings, many fillers, due to their large specific surface area, are prone to agglomeration in the rubber matrix. This not only leads to uneven local performance of the sealing ring but may also cause stress concentration, thereby reducing the material's service life. Furthermore, interfacial defects may exist between the filler and the rubber matrix, affecting load transfer efficiency and thus reducing the overall performance of the material. Excessive filler may also impair the rubber's elasticity, abrasion resistance, or processability. Summary of the Invention

[0006] To address the aforementioned technical problems, this application provides a polymer sealing ring and its preparation method.

[0007] This application provides a polymer sealing ring, which adopts the following technical solution:

[0008] A polymer sealing ring, the raw materials comprising, by mass percentage: 30-50% fluorinated modified silicone rubber, 15-25% fluororubber, 7.2-16.4% hybrid silica, 2.5-6% hydroxyl silicone oil, 8-11% plasma-modified fluorinated alumina, 4-8% carbon black, 0.8-1.4% palm wax, 0.8-1.4% internal release agent, 1-2% vulcanizing agent, 3-5% triallyl isocyanurate, and 0.5-1% antioxidant.

[0009] Preferably, the raw materials comprise, by mass percentage, 40% fluorinated modified silicone rubber, 20% fluororubber, 11.9% hybrid silica, 4.2% hydroxyl silicone oil, 9.5% plasma-modified fluorinated alumina, 6% carbon black, 1.1% palm wax, 1.1% internal release agent, 1.5% vulcanizing agent, 4% triallyl isocyanurate, and 0.7% antioxidant.

[0010] Preferably, the fluorinated modified silicone rubber is prepared from the following raw materials in parts by weight: 3-7 parts methyl vinyl silicone rubber, 27-63 parts tetrahydrofuran, 6.6-15.4 parts C2-18-perfluoroalkyl iodoethane, 0.024-0.056 parts photoinitiator, and 48-110 parts anhydrous ethanol.

[0011] Preferably, the photoinitiator is benzoin dimethyl ether.

[0012] Preferably, the preparation method of the fluorinated modified silicone rubber includes the following steps:

[0013] Methyl vinyl silicone rubber was added to tetrahydrofuran and stirred with a magnetic stirrer until fully dissolved. Then, C2-18-perfluoroalkyl iodoethane was added and the mixture was stirred for 30-50 minutes. A photoinitiator was then added and the mixture was irradiated with ultraviolet light in a closed environment for 5-10 minutes. After the reaction was completed, the mixed solution was added to anhydrous ethanol for flocculation to obtain the product. The product was then vacuum dried at 55-65℃ to obtain fluorinated modified silicone rubber.

[0014] Preferably, the hybrid silica is prepared from the following raw materials in parts by weight: 240-360 parts anhydrous ethanol, 5-8 parts oleic acid, 22-33 parts tetraethyl orthosilicate, 5-7.5 parts silane coupling agent KH560, and 100-150 parts deionized water.

[0015] Preferably, the method for preparing the hybrid silica includes the following steps:

[0016] Oleic acid was added to anhydrous ethanol and stirred until completely dissolved. Then tetraethyl orthosilicate, silane coupling agent KH560 and deionized water were added and stirred evenly. The pH of the solution was adjusted to 10-11. The reaction was then magnetically stirred at 60-70℃ and 800-1000 rpm for 6-8 hours. After the reaction was completed, the product was washed and dried to obtain hybrid silica.

[0017] Preferably, the method for preparing plasma-fluorinated modified alumina includes the following steps:

[0018] S1. By weight, add 150-200 parts of ethanol aqueous solution to 10-15 parts of nano alumina, stir until fully dissolved, stir at 50-60℃ and 4000-5000rpm for 20-30 minutes, add 1-1.5 parts of silane coupling agent KH560, then add 50-75 parts of ethanol aqueous solution, continue stirring for 40-60 minutes, dry the mixed solution at 80-90℃ for 48-54 hours, grind into powder to obtain silane coupling agent modified nano alumina;

[0019] S2. Place the silane coupling agent-modified nano-alumina into the reactor and evacuate until the pressure inside the reactor is 1.8 × 10⁻⁶. -3 -2.8×10 -3 Pa; then a mixture of carbon tetrafluoride and nitrogen gas is introduced into the reactor until the pressure inside the reactor rises to 13-14 kPa; after applying voltage and performing plasma fluorination treatment for 30-40 min, plasma fluorinated modified alumina is obtained.

[0020] Preferably, the voltage is 22-26kV.

[0021] This application also provides a method for preparing a polymer sealing ring, using the following technical solution:

[0022] A method for preparing a polymer sealing ring includes the following steps:

[0023] S1. Weigh the raw materials as follows by mass percentage: fluorinated modified silicone rubber, fluororubber, hybrid silica, hydroxyl silicone oil, plasma fluorinated modified alumina, carbon black, palm wax, internal release agent, vulcanizing agent, triallyl isocyanurate, and antioxidant; add the raw materials to a mixer and mix at 40-50℃ for 5-8 minutes to obtain the rubber compound;

[0024] S2. Add the rubber material to the injection molding machine and injection mold to obtain the precursor of the silicone rubber sealing ring;

[0025] S3. Place the silicone rubber sealing ring precursor into a vulcanizer and vulcanize it for 25-35 minutes at a temperature of 165-175℃ and a pressure of 15-17MPa; then place it in an oven and vulcanize it again for 3-4 hours at a temperature of 180-220℃ to obtain the silicone rubber sealing ring.

[0026] In summary, this application includes at least one of the following beneficial technical effects:

[0027] 1. By adopting the above technical solution, this application prepares fluorinated modified silicone rubber by grafting C2-18-perfluoroalkyl iodoethane onto the side chain of silicone rubber, which effectively improves the low-temperature resistance of silicone rubber and successfully suppresses the low-temperature easy crystallization phenomenon of methyl vinyl silicone rubber. In addition, fluororubber has stable performance at high temperatures. The modified silicone rubber provided by this application also solves the problem of poor compatibility of traditional fluorinated / silicone blends. By blending fluorinated modified silicone rubber with fluororubber as the base material of the sealing ring, the resulting sealing ring material has good performance at both high and low temperatures, which greatly improves the operating temperature range of the polymer sealing ring.

[0028] 2. This application employs a one-pot method to treat in-situ generated silica with a combination of silane coupling agent and oleic acid to prepare hybrid silica. The presence of the silane coupling agent enhances the compatibility between silica and rubber molecular chains, while the coating modification with oleic acid can form a film on the surface of silica particles, which helps reduce the agglomeration of silica particles and significantly improves the dispersibility and compatibility of silica in silicone rubber materials, thereby enhancing the reinforcing effect of silica on rubber materials.

[0029] 3. In this application, after the nano-alumina is modified by coupling with a silane coupling agent, the surface of the silane coupling agent-modified alumina is fluorinated by plasma fluorination treatment to achieve fluorination modification of alumina. This significantly improves the dispersibility and compatibility of nano-alumina in silicone rubber materials, effectively accelerates the vulcanization reaction, increases the crosslinking density, and improves the hardness and wear resistance of the sealing ring material. Detailed Implementation

[0030] The present application will be further described in detail below with reference to the embodiments.

[0031] The chemical reagents used in the preparation examples, embodiments, and comparative examples provided in this invention are all commercially available products, and their brands and manufacturers are as follows:

[0032] Methyl vinyl silicone rubber, Condis Chemical (Hubei) Co., Ltd.;

[0033] C2-18-Perfluoroalkyliodoethane, Xiaogan Shenyuan Chemical Co., Ltd.;

[0034] Fluororubber, Guangdong Wengjiang Chemical Reagent Co., Ltd., FKM246;

[0035] Hydroxysilicone oil, Hubei Zhonglong Kangcheng Fine Chemical Co., Ltd.;

[0036] Carbon black, Tianjin Yiborui Chemical Co., Ltd., Carbon black N990;

[0037] Palm wax, Wuhan Hongde Yuexin Pharmaceutical Technology Co., Ltd.;

[0038] WS-280, Dongguan Yuebang Rubber Technology Co., Ltd.

[0039] Preparation Example 1: Preparation of Fluorinated Modified Silicone Rubber

[0040] Preparation Example 1.1

[0041] 3g of methyl vinyl silicone rubber was added to 27g of tetrahydrofuran and magnetically stirred until fully dissolved. Then, 6.6g of C2-18-perfluoroalkyl iodoethane was added and the mixture was stirred for 30 minutes. Then, 0.024g of benzoin dimethyl ether was added. The grafting reaction was initiated by irradiation with a 365nm wavelength ultraviolet lamp in a closed environment for 5 minutes. After the reaction was completed, the mixed solution was added to 48g of anhydrous ethanol for flocculation to obtain the product. The product was then vacuum dried at 55℃ to obtain fluorinated modified silicone rubber.

[0042] Preparation Example 1.2

[0043] Add 5g of methyl vinyl silicone rubber to 45g of tetrahydrofuran and stir magnetically until fully dissolved. Then add 11g of C2-18-perfluoroalkyl iodoethane and continue mixing and stirring for 40min. Then add 0.04g of benzoin dimethyl ether and irradiate with a 365nm wavelength ultraviolet lamp in a closed environment to initiate the grafting reaction for 8min. After the reaction is completed, add the mixed solution to 79g of anhydrous ethanol for flocculation to obtain the product. Dry the product under vacuum at 60℃ to obtain fluorinated modified silicone rubber.

[0044] Preparation Example 1.3

[0045] 7g of methyl vinyl silicone rubber was added to 63g of tetrahydrofuran and magnetically stirred until fully dissolved. Then, 15.4g of C2-18-perfluoroalkyl iodoethane was added and the mixture was stirred for 50min. Then, 0.056g of benzoin dimethyl ether was added. The grafting reaction was initiated by irradiation with a 365nm wavelength ultraviolet lamp in a closed environment for 10min. After the reaction was completed, the mixed solution was added to 110g of anhydrous ethanol for flocculation to obtain the product. The product was then vacuum dried at 65℃ to obtain fluorinated modified silicone rubber.

[0046] Preparation Example 2: Preparation of Hybridized Silica

[0047] Preparation Example 2.1

[0048] 5g of oleic acid was added to 240g of anhydrous ethanol and stirred until completely dissolved. Then, 22g of tetraethyl orthosilicate, 5g of silane coupling agent KH560 and 100g of deionized water were added and stirred evenly. The pH of the solution was adjusted to 10 with ammonia. The reaction was then carried out under magnetic stirring at 60℃ and 800rpm for 6 hours. After the reaction was completed, the product was washed and dried to obtain hybrid silica.

[0049] Preparation Example 2.2

[0050] 6.5g of oleic acid was added to 300g of anhydrous ethanol and stirred until completely dissolved. Then, 27.5g of tetraethyl orthosilicate, 6.3g of silane coupling agent KH560 and 125g of deionized water were added and stirred evenly. The pH of the solution was adjusted to 10.5 with ammonia. The reaction was then magnetically stirred at 65℃ and 900rpm for 7h. After the reaction was completed, the product was washed and dried to obtain hybrid silica.

[0051] Preparation Example 2.3

[0052] 8g of oleic acid was added to 360g of anhydrous ethanol and stirred until completely dissolved. Then, 33g of tetraethyl orthosilicate, 7.5g of silane coupling agent KH560 and 150g of deionized water were added and stirred evenly. The pH of the solution was adjusted to 11 with ammonia. The reaction was then carried out under magnetic stirring at 70℃ and 1000rpm for 8 hours. After the reaction was completed, the product was washed and dried to obtain hybrid silica.

[0053] Preparation Example 3: Plasma Fluorination Modified Alumina

[0054] Preparation Example 3.1

[0055] S1. Add 150g of ethanol-water solution (the mass ratio of ethanol to water is 6:1) to 10g of nano-alumina, stir until fully dissolved, stir at 50℃ and 4000rpm for 20min, add 1g of silane coupling agent KH560, then add 50g of ethanol-water solution (the mass ratio of ethanol to water is 6:1), continue stirring for 40min, dry the mixed solution at 80℃ for 48h, grind it into powder to obtain silane coupling agent modified nano-alumina;

[0056] S2. Place the silane coupling agent-modified nano-alumina into the reactor and evacuate until the pressure inside the reactor is 2.8 × 10⁻⁶. - 3 Pa; then a mixture of carbon tetrafluoride and nitrogen (volume ratio of carbon tetrafluoride and nitrogen is 4:1) is introduced into the reactor until the pressure inside the reactor rises to 14 kPa; a voltage of 22 kV is applied, and plasma fluorination treatment is performed for 30 min to obtain plasma fluorinated modified alumina.

[0057] Preparation Example 3.2

[0058] S1. Add 175g of ethanol-water solution (the mass ratio of ethanol to water is 8:1) to 12.5g of nano-alumina, stir until fully dissolved, stir at 55℃ and 4500rpm for 25min, add 1.25g of silane coupling agent KH560, then add 62.5g of ethanol-water solution (the mass ratio of ethanol to water is 8:1), continue stirring for 50min, dry the mixed solution at 85℃ for 51h, grind it into powder to obtain silane coupling agent modified nano-alumina;

[0059] S2. Place the silane coupling agent-modified nano-alumina into the reactor and evacuate until the pressure inside the reactor reaches 2.3 × 10⁻⁶. - 3 Pa; then a mixture of carbon tetrafluoride and nitrogen (volume ratio of carbon tetrafluoride and nitrogen is 4:1) is introduced into the reactor until the pressure inside the reactor rises to 13.5 kPa; a voltage of 24 kV is applied, and plasma fluorination treatment is performed for 35 min to obtain plasma fluorinated modified alumina.

[0060] Preparation Example 3.3

[0061] S1. Add 200g of ethanol-water solution (the mass ratio of ethanol to water is 9:1) to 15g of nano-alumina, stir until fully dissolved, stir at 60℃ and 5000rpm for 30min, add 1.5g of silane coupling agent KH560, then add 75g of ethanol-water solution (the mass ratio of ethanol to water is 9:1), continue stirring for 60min, dry the mixed solution at 90℃ for 54h, grind it into powder to obtain silane coupling agent modified nano-alumina;

[0062] S2. Place the silane coupling agent-modified nano-alumina into the reactor and evacuate until the pressure inside the reactor is 1.8 × 10⁻⁶. - 3 Pa; then a mixture of carbon tetrafluoride and nitrogen (volume ratio of carbon tetrafluoride and nitrogen is 4:1) is introduced into the reactor until the pressure inside the reactor rises to 13 kPa; a voltage of 26 kV is applied, and plasma fluorination treatment is performed for 40 min to obtain plasma fluorinated modified alumina.

[0063] Example 1

[0064] S1. Weigh out 30g of fluorinated modified silicone rubber and 25g of fluororubber prepared in Preparation Example 1.1, 16.4g of hybrid silica prepared in Preparation Example 2.1, 6g of hydroxyl silicone oil, 8g of plasma fluorinated modified alumina prepared in Preparation Example 3.1, 8g of carbon black, 0.8g of palm wax, 0.8g of internal release agent, 1g of vulcanizing agent, 3g of triallyl isocyanurate, and 1g of antioxidant, based on 100g of raw materials; add the raw materials to a mixer and mix at 40°C for 8 minutes to obtain the rubber compound;

[0065] S2. Add the rubber material to the injection molding machine, and injection mold it at a barrel temperature of 200℃ and a nozzle temperature of 190℃ to obtain the polymer rubber sealing ring precursor.

[0066] S3. Place the silicone rubber sealing ring precursor into a flat vulcanizing apparatus and vulcanize it for 25 minutes at a temperature of 165℃ and a pressure of 15MPa; then place it in an oven and vulcanize it again for 3 hours at a temperature of 180℃ to obtain the polymer sealing ring.

[0067] The internal release agent used in this embodiment is WS-280; the vulcanizing agent used is 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane; and the antioxidant used consists of antioxidant BHT, ultraviolet absorber UV-531, and antioxidant DTPD in a mass ratio of 1:1:3.

[0068] Example 2

[0069] S1. Weigh out 40g of fluorinated modified silicone rubber, 20g of fluororubber, 11.9g of hybrid silica, 4.2g of hydroxyl silicone oil, 9.5g of plasma fluorinated modified alumina, 6g of carbon black, 1.1g of palm wax, 1.1g of internal release agent, 1.5g of vulcanizing agent, 4g of triallyl isocyanurate, and 0.7g of antioxidant per 100g. Add the raw materials to a mixer and mix at 40°C for 8 minutes to obtain the rubber compound.

[0070] S2. Add the rubber material to the injection molding machine, and injection mold it at a barrel temperature of 200℃ and a nozzle temperature of 190℃ to obtain the polymer rubber sealing ring precursor.

[0071] S3. Place the silicone rubber sealing ring precursor into a flat vulcanizing apparatus and vulcanize it for 25 minutes at a temperature of 165℃ and a pressure of 15MPa; then place it in an oven and vulcanize it again for 3 hours at a temperature of 180℃ to obtain the polymer sealing ring.

[0072] The internal release agent used in this embodiment is WS-280; the vulcanizing agent used is 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane; and the antioxidant used consists of antioxidant BHT, ultraviolet absorber UV-531, and antioxidant DTPD in a mass ratio of 1:1:3.

[0073] Example 3

[0074] S1. Weigh out 50g of fluorinated modified silicone rubber, 15g of fluororubber, 7.2g of hybrid silica, 2.5g of hydroxyl silicone oil, 11g of plasma fluorinated modified alumina, 4g of carbon black, 1.4g of palm wax, 1.4g of internal release agent, 2g of vulcanizing agent, 5g of triallyl isocyanurate, and 0.5g of antioxidant per 100g. Add the raw materials to a mixer and mix at 40°C for 8 minutes to obtain the rubber compound.

[0075] S2. Add the rubber material to the injection molding machine, and injection mold it at a barrel temperature of 200℃ and a nozzle temperature of 190℃ to obtain the polymer rubber sealing ring precursor.

[0076] S3. Place the silicone rubber sealing ring precursor into a flat vulcanizing apparatus and vulcanize it for 25 minutes at a temperature of 165℃ and a pressure of 15MPa; then place it in an oven and vulcanize it again for 3 hours at a temperature of 180℃ to obtain the polymer sealing ring.

[0077] The internal release agent used in this embodiment is WS-280; the vulcanizing agent used is 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane; and the antioxidant used consists of antioxidant BHT, ultraviolet absorber UV-531, and antioxidant DTPD in a mass ratio of 1:1:3.

[0078] Example 4

[0079] S1. Weigh out 30g of fluorinated modified silicone rubber, 25g of fluororubber, 16.4g of hybrid silica, 6g of hydroxyl silicone oil, 8g of plasma fluorinated modified alumina, 8g of carbon black, 0.8g of palm wax, 0.8g of internal release agent, 1g of vulcanizing agent, 3g of triallyl isocyanurate, and 1g of antioxidant per 100g. Add the raw materials to a mixer and mix at 45°C for 7 minutes to obtain the rubber compound.

[0080] S2. Add the rubber material to the injection molding machine, and injection mold it at a barrel temperature of 210℃ and a nozzle temperature of 200℃ to obtain the polymer rubber sealing ring precursor.

[0081] S3. Place the silicone rubber sealing ring precursor into a flat vulcanizing apparatus and vulcanize it at a temperature of 170℃ and a pressure of 16MPa for 30 minutes; then place it in an oven and vulcanize it again at a temperature of 200℃ for 3.5 hours to obtain the polymer rubber sealing ring.

[0082] The internal release agent used in this embodiment is WS-280; the vulcanizing agent used is 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane; and the antioxidant used consists of antioxidant BHT, ultraviolet absorber UV-531, and antioxidant DTPD in a mass ratio of 1:1:3.

[0083] Example 5

[0084] S1. Weigh out 30g of fluorinated modified silicone rubber and 25g of fluororubber prepared in Preparation Example 1.1, 16.4g of hybrid silica prepared in Preparation Example 2.1, 6g of hydroxyl silicone oil, 8g of plasma fluorinated modified alumina prepared in Preparation Example 3.1, 8g of carbon black, 0.8g of palm wax, 0.8g of internal release agent, 1g of vulcanizing agent, 3g of triallyl isocyanurate, and 1g of antioxidant, based on a weight of 100g. Add the raw materials to a mixer and mix at 50°C for 5 minutes to obtain the rubber compound.

[0085] S2. Add the rubber material into the injection molding machine, and injection mold it at a barrel temperature of 220℃ and a nozzle temperature of 230℃ to obtain the polymer rubber sealing ring precursor.

[0086] S3. Place the silicone rubber sealing ring precursor into a flat vulcanizing apparatus and vulcanize it for 35 minutes at a temperature of 175℃ and a pressure of 17MPa; then place it in an oven and vulcanize it again for 4 hours at a temperature of 220℃ to obtain the polymer sealing ring.

[0087] The internal release agent used in this embodiment is WS-280; the vulcanizing agent used is 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane; and the antioxidant used consists of antioxidant BHT, ultraviolet absorber UV-531, and antioxidant DTPD in a mass ratio of 1:1:3.

[0088] Example 6

[0089] The difference between Example 6 and Example 1 is that the fluorinated modified silicone rubber used in Example 6 was prepared by Preparation Example 1.2.

[0090] Example 7

[0091] The difference between Example 7 and Example 1 is that the fluorinated modified silicone rubber used in Example 7 was prepared from Preparation Example 1.3.

[0092] Example 8

[0093] The difference between Example 8 and Example 1 is that the hybrid silica used in Example 8 was prepared from Preparation Example 2.2.

[0094] Example 9

[0095] The difference between Example 9 and Example 1 is that the hybrid silica used in Example 9 was prepared from Preparation Example 2.3.

[0096] Example 10

[0097] The difference between Example 10 and Example 1 is that the plasma-fluorinated modified alumina used in Example 10 was prepared from Preparation Example 3.2.

[0098] Example 11

[0099] The difference between Example 11 and Example 1 is that the plasma-fluorinated modified alumina used in Example 11 was prepared from Preparation Example 3.3.

[0100] Comparative Example 1

[0101] The difference between Comparative Example 1 and Example 1 is that the silicone rubber used in Comparative Example 1 is methyl vinyl silicone rubber that has not been fluorinated.

[0102] Comparative Example 2

[0103] The difference between Comparative Example 2 and Example 1 is that the silica used in Comparative Example 2 is commercially available fumed silica, purchased from Jiangxi Hongbai New Materials Co., Ltd.

[0104] Comparative Example 3

[0105] The difference between Comparative Example 3 and Example 1 is that the alumina used in Comparative Example 3 is nano-alumina that has not undergone plasma fluorination modification.

[0106] Comparative Example 4

[0107] The difference between Comparative Example 4 and Example 1 is that no fluororubber was added in Comparative Example 4, but an equal amount of fluorinated modified silicone rubber was used instead.

[0108] Performance testing

[0109] I. The tensile strength and elongation at break of the polymer sealing rings obtained in Examples 1-11 and Comparative Examples 1-4 were tested according to ASTM-D3574-08, and the results are shown in Table 1.

[0110] II. Weather resistance test: Referring to GB / T 3511-2018, the polymer sealing ring samples obtained in Examples 1-11 and Comparative Examples 1-4 were irradiated for 168 hours, and the performance retention percentage of their tensile strength was tested and calculated. The results are shown in Table 1.

[0111] III. High and low temperature alternating environment test: The polymer sealing rings obtained in Examples 1-11 and Comparative Examples 1-4 were placed in an environment of 100℃ for 5 hours, and then placed in an environment of -20℃ for 5 hours. The cycle was repeated 100 times. The performance retention percentage of tensile strength was tested and calculated. The results are shown in Table 1.

[0112] The specific test results are as follows:

[0113]

[0114] As can be seen from the test results in Table 1, the polymer sealing ring provided in this application has strong tensile strength and elongation at break, and the tensile strength performance retention rate can reach more than 98% after irradiation for 168 hours, indicating that the polymer sealing ring provided in this application has excellent weather resistance. In addition, after the polymer sealing ring provided in this application is subjected to cyclic alternating placement tests in environments of 100℃ and -20℃, its tensile strength performance retention rate can reach more than 98%, indicating that the polymer sealing ring provided in this application has excellent temperature change resistance and has a wide range of applications.

[0115] 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 polymer sealing ring, characterized in that: The raw materials, by weight percentage, include 30-50% fluorinated modified silicone rubber, 15-25% fluororubber, 7.2-16.4% hybrid silica, 2.5-6% hydroxyl silicone oil, 8-11% plasma-modified fluorinated alumina, 4-8% carbon black, 0.8-1.4% palm wax, 0.8-1.4% internal release agent, 1-2% vulcanizing agent, 3-5% triallyl isocyanurate, and 0.5-1% antioxidant. The fluorinated modified silicone rubber is prepared from the following raw materials in parts by weight: 3-7 parts methyl vinyl silicone rubber, 27-63 parts tetrahydrofuran, 6.6-15.4 parts C2-18-perfluoroalkyl iodoethane, 0.024-0.056 parts photoinitiator, and 48-110 parts anhydrous ethanol; The hybrid silica is prepared from the following raw materials in parts by weight: 240-360 parts anhydrous ethanol, 5-8 parts oleic acid, 22-33 parts tetraethyl orthosilicate, 5-7.5 parts silane coupling agent KH560, and 100-150 parts deionized water. The method for preparing plasma-fluorinated modified alumina includes the following steps: S1. By weight, add 150-200 parts of ethanol aqueous solution to 10-15 parts of nano alumina, stir until fully dissolved, stir at 50-60℃ and 4000-5000rpm for 20-30 minutes, add 1-1.5 parts of silane coupling agent KH560, then add 50-75 parts of ethanol aqueous solution, continue stirring for 40-60 minutes, dry the mixed solution at 80-90℃ for 48-54 hours, grind into powder to obtain silane coupling agent modified nano alumina; S2. Place the silane coupling agent-modified nano-alumina into the reactor and evacuate until the pressure inside the reactor is 1.8 × 10⁻⁶. -3 -2.8×10 -3 Pa; then a mixture of carbon tetrafluoride and nitrogen gas is introduced into the reactor until the pressure inside the reactor rises to 13-14 kPa; after applying voltage and performing plasma fluorination treatment for 30-40 min, plasma fluorinated modified alumina is obtained.

2. The polymer sealing ring according to claim 1, characterized in that: The raw materials, by mass percentage, include 40% fluorinated modified silicone rubber, 20% fluororubber, 11.9% hybrid silica, 4.2% hydroxyl silicone oil, 9.5% plasma-modified fluorinated alumina, 6% carbon black, 1.1% palm wax, 1.1% internal release agent, 1.5% vulcanizing agent, 4% triallyl isocyanurate, and 0.7% antioxidant.

3. The polymer sealing ring according to claim 1, characterized in that: The photoinitiator is benzoin dimethyl ether.

4. The polymer sealing ring according to claim 1, characterized in that: The preparation method of the fluorinated modified silicone rubber includes the following steps: Methyl vinyl silicone rubber was added to tetrahydrofuran and magnetically stirred until fully dissolved. Then, C2-18-perfluoroalkyl iodoethane was added and the mixture was stirred for 30-50 minutes. A photoinitiator was then added and the mixture was irradiated with ultraviolet light in a closed environment for 5-10 minutes. After the reaction was completed, the mixed solution was added to anhydrous ethanol for flocculation to obtain the product. The product was then vacuum dried at 55-65℃ to obtain fluorinated modified silicone rubber.

5. A polymer sealing ring according to claim 1, characterized in that: The method for preparing the hybrid silica includes the following steps: Oleic acid was added to anhydrous ethanol and stirred until completely dissolved. Then tetraethyl orthosilicate, silane coupling agent KH560 and deionized water were added and stirred evenly. The pH of the solution was adjusted to 10-11. The reaction was then magnetically stirred at 60-70℃ and 800-1000 rpm for 6-8 hours. After the reaction was completed, the product was washed and dried to obtain hybrid silica.

6. The polymer sealing ring according to claim 1, characterized in that: The voltage is 22-26kV.

7. A method for preparing a polymer sealing ring according to any one of claims 1-6, characterized in that: Includes the following steps: S1. Weigh the raw materials as follows by mass percentage: fluorinated modified silicone rubber, fluororubber, hybrid silica, hydroxyl silicone oil, plasma fluorinated modified alumina, carbon black, palm wax, internal release agent, vulcanizing agent, triallyl isocyanurate, and antioxidant; add the raw materials to a mixer and mix at 40-50℃ for 5-8 minutes to obtain the rubber compound; S2. Add the rubber material to the injection molding machine and injection mold to obtain the polymer rubber sealing ring precursor; S3. Place the silicone rubber sealing ring precursor into a vulcanizer and vulcanize it for 25-35 minutes at a temperature of 165-175℃ and a pressure of 15-17MPa; then place it in an oven and vulcanize it again for 3-4 hours at a temperature of 180-220℃ to obtain the polymer sealing ring.

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