Wading rubber sealing rubber ring and preparation method thereof

Abstract

The invention belongs to the technical field of rubber sealing rings, and particularly discloses a wading rubber sealing ring and a preparation method thereof, the wading rubber sealing ring comprises the following components by weight: 60-70 parts of modified ethylene propylene diene monomer, 35-50 parts of modified white carbon black, 20-30 parts of hydrogenated nitrile rubber, 0-10 parts of fluororubber, 2-5 parts of polyester fiber, 0.5-3 parts of an anti-hydrolysis agent, and 1-3 parts of a hydrophobic agent. 2-4 parts of an antimicrobial agent, 3-5 parts of an anti-aging agent and 1-7 parts of sulfur; the anti-hydrolysis agent is a mixture of tetrakis [beta-(3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester and a carbodiimide anti-hydrolysis agent; the hydrophobic agent is a mixture of polydimethylsiloxane and perfluorooctyltriethoxysilane, and the hydrophobic agent is a mixture of polydimethylsiloxane and perfluorooctyltriethoxysilane. The wading rubber sealing rubber ring and the preparation method thereof are suitable for fresh water and warm water scenes, and have wide application prospects in ship sealing and sewage treatment equipment in seawater and industrial wastewater scenes.

Description

Technical Field

[0001] This invention relates to the field of rubber sealing ring technology, and in particular to a water-resistant rubber sealing ring and its preparation method. Background Technology

[0002] Rubber sealing rings possess excellent elasticity and sealing performance, preventing water leakage and improving connection strength to a certain extent. However, existing water-resistant rubber sealing rings are subject to prolonged contact with fresh water, seawater, or industrial wastewater, facing challenges such as water penetration, hydrolytic aging, microbial adhesion, and chemical corrosion. In particular, while ethylene propylene diene monomer (EPDM) rubber possesses basic water resistance, its performance degrades under prolonged immersion (over 3 months) or high-temperature water environments above 60°C due to the hydrolysis of weak bonds in its molecular chains caused by the unsaturated double bonds and small amounts of polar groups in the EPDM side chains. Summary of the Invention

[0003] The purpose of this invention is to provide a water-contact rubber sealing ring and its preparation method, which is suitable for freshwater and warm water scenarios and has broad application prospects in marine sealing and sewage treatment equipment in seawater and industrial wastewater scenarios.

[0004] To achieve the above objectives, the present invention provides a water-resistant rubber sealing ring, comprising the following weight proportions:

[0005] Modified EPDM rubber 60-70 parts, modified silica 35-50 parts, hydrogenated nitrile butadiene rubber 20-30 parts, fluororubber 0-10 parts, polyester fiber 2-5 parts, anti-hydrolysis agent 0.5-3 parts, hydrophobic agent 1-3 parts, antimicrobial agent 2-4 parts, antioxidant 3-5 parts, sulfur 1-7 parts.

[0006] The anti-hydrolysis agent is a mixture of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] and carbodiimide anti-hydrolysis agents, used to block the hydrolysis reaction chain;

[0007] The hydrophobic agent is a mixture of polydimethylsiloxane and perfluorooctyltriethoxysilane, used to construct a surface hydrophobic barrier;

[0008] The antimicrobial agent is nano-zinc oxide, which not only acts as a sulfidation activator but also releases Zn. 2+ It disrupts the cell membranes of microorganisms, inhibiting the growth of bacteria (Escherichia coli, Staphylococcus aureus);

[0009] The antioxidant is N,N'-bis(β-naphthyl)-p-phenylenediamine, which has low solubility in water (≤0.01g / L) and an antioxidant retention rate of ≥90% after soaking for 72 hours.

[0010] Preferably, the ratio of the tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] pentaerythritol ester to the carbodiimide antihydrolysis agent is 2:1, by mass.

[0011] Preferably, the ratio of polydimethylsiloxane to perfluorooctyltriethoxysilane is 6-3:1, by mass.

[0012] This invention also provides a method for preparing a water-resistant rubber sealing ring, comprising the following steps:

[0013] S1. Raw material pretreatment: Modified EPDM rubber and hydrogenated nitrile rubber are preheated in an oven at 60-70℃ for 2-3 hours to obtain a substrate with a moisture content of less than 0.1%.

[0014] S2. Pre-dispersion of functional additives: Mix nano zinc oxide and anti-hydrolysis agent, grind to obtain functional additive masterbatch with a particle size of less than 5μm;

[0015] S3, Substrate Plasticizing: Set the initial temperature of the internal mixer to 80-90℃, first add fluororubber and the substrate obtained in S1 (modified EPDM rubber and hydrogenated nitrile rubber), plasticize for 3-5 minutes until the rubber compound softens, add polyester fiber, mix for 2-3 minutes to make the fiber evenly dispersed, and at the same time control the discharge temperature below 110℃ to avoid heat degradation of the fiber.

[0016] S4, Reinforcement: Raise the temperature of the internal mixer to 90-100℃, add modified silica in 2-3 batches with an interval of 1-3 minutes between each batch, mix for 5-7 minutes, add hydrophobic agent and functional additive masterbatch obtained in S2 in sequence, mix for 3-4 minutes, and then discharge the glue.

[0017] S5, Thin pass: Transfer to open mill, initially set the roller temperature to 50-60℃ and the roller gap to 1-2mm, add N,N'-bis(β-naphthyl)p-phenylenediamine, thin pass 4-5 times, then add sulfur, adjust the roller gap to 0.5mm, thin pass 6-8 times, let stand for 12-24h to obtain rubber compound;

[0018] S6. First stage of vulcanization: Transfer the rubber compound to the mold, set the temperature to 145-155℃, the pressure to 10-12MPa, and the vulcanization time to 6-8min, accounting for 40% of the total vulcanization time.

[0019] S7. Second stage vulcanization: Temperature set at 165-175℃, pressure at 15-18MPa, vulcanization time at 8-10min, accounting for 50% of the total vulcanization time;

[0020] S8. Third stage vulcanization: The temperature is set to 115-125℃, the pressure to 5-8MPa, and the vulcanization time to 1.5-2min, accounting for 10% of the total vulcanization time, to obtain the rubber ring.

[0021] S9. Boiling and surface activation treatment: The rubber ring obtained in S7 is soaked in deionized water at 80-90℃ for 2-3 hours to remove residual vulcanizing agents and small molecules, reduce extractables in later use, and then naturally cooled to room temperature to avoid structural stress caused by sudden cooling. Low-temperature plasma treatment is used to further improve the surface hydrophobicity and remove residual impurities on the surface to obtain a water-resistant rubber sealing ring.

[0022] Preferably, the preparation method of the modified EPDM rubber includes the following steps:

[0023] According to the proportion, set the initial temperature of the internal mixer to 80-90℃, add EPDM rubber and plasticize for 3-5 minutes, then add antioxidant and mix for 0.5-1 minutes. Add maleic anhydride in 2-3 batches, mixing for 1.5-2.5 minutes after each addition. Raise the temperature of the internal mixer to 150-160℃, add initiator and dispersant and plasticize for 5-8 minutes. Transfer the rubber compound discharged from the internal mixer to a single-screw extruder with a discharge temperature of 160-170℃ to obtain modified EPDM rubber granules of 2-3 mm.

[0024] Preferably, the dispersant is zinc stearate, the initiator is dicumyl peroxide, and the antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], with a dosage ratio of EPDM rubber: maleic anhydride: initiator: antioxidant: dispersant = 100:7:1:0.3:0.4, by mass.

[0025] Preferably, the preparation method of the hydrogenated nitrile butadiene rubber includes the following steps:

[0026] According to the proportion, the nitrile rubber solution was transferred to a high-pressure reactor, triethylamine and antioxidant were added and stirred, nitrogen gas was introduced, Pd / C catalyst was added, rhodium-based catalyst was slowly added and stirred, nitrogen gas was turned off and hydrogen gas was introduced, and the reaction was activated by stirring at a constant temperature and pressure of 2-3 MPa and 80-90℃. Then the temperature and pressure were increased to 8-12 MPa and 100-120℃ and hydrogenation was carried out for 6-10 hours. After the reaction was completed, hydrogen gas was turned off and nitrogen gas was introduced. The solid product was taken out, purified to remove residual catalyst, washed and dried to obtain hydrogenated nitrile rubber.

[0027] Preferably, the ratio of the nitrile rubber: the triethylamine: the antioxidant: the Pd / C catalyst: the rhodium-based catalyst is 100:0.3:0.4:0.5:1, by mass.

[0028] Preferably, the preparation method of the modified silica includes the following steps:

[0029] Add silica and KH-570 silane coupling agent to a high-speed mixer at a ratio of 100:3, and mix for 15-20 minutes at 120-130℃ and 1500 r / min to ensure that the coupling agent completely coats the surface of silica, thus obtaining modified silica.

[0030] Preferably, the power of the low-temperature plasma treatment is 300W and the time is 30-60s.

[0031] Therefore, the present invention employs the above-mentioned water-resistant rubber sealing ring and its preparation method, and the beneficial effects are as follows:

[0032] The polar groups of the modified EPDM rubber of this invention can form weak hydrogen bonds with water molecules, reducing the penetration of water into the rubber interior; the saturated molecular chain (few double bonds) of the hydrogenated nitrile rubber avoids the problem of double bond breakage in the hydrolysis reaction, while the cyano group (-CN) can enhance the intermolecular forces and improve the water swelling resistance (the volume swelling rate after soaking for 72 hours is ≤8%, which is much lower than the 15% volume swelling rate of ordinary EPDM rubber); nano zinc oxide inhibits bacterial growth, with an antibacterial rate of ≥99% against Escherichia coli.

[0033] The gradient vulcanization molding process of this invention employs a first stage at low temperature and medium pressure to construct a basic cross-linked network, resulting in a highly elastic rubber layer. Simultaneously, silica and rubber molecules undergo initial bonding, laying the foundation for the formation of the outer waterproof and wear-resistant layer (dense structure). The second stage utilizes high temperature and high pressure to enhance cross-linking and structural shaping, eliminating intermolecular gaps and forming a porous, dense structure. This also promotes the migration of hydrophobic agents to the surface, constructing a hydrophobic barrier. The third stage uses low temperature and low pressure to eliminate internal stress and the volatilization of small molecules, preventing residual substances from being extracted by water during subsequent water immersion and affecting sealing performance. Overall, this process balances "inner layer elasticity" and "outer layer protection," reducing water permeability and improving tensile strength retention under immersion and resistance to hydrolytic aging.

[0034] The water-contact rubber sealing ring prepared by this invention is suitable for freshwater and warm water (≤80℃) scenarios, and has broad application prospects in marine sealing and sewage treatment equipment in seawater and industrial wastewater scenarios.

[0035] The technical solution of the present invention will be further described in detail below through embodiments. Detailed Implementation

[0036] The technical solution of the present invention will be further described below through embodiments.

[0037] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0038] Example 1

[0039] A water-resistant rubber sealing ring, comprising the following components by weight:

[0040] 65 parts modified EPDM rubber, 40 parts modified silica, 25 parts hydrogenated nitrile rubber, 5 parts fluororubber, 3 parts polyester fiber, 1.5 parts anti-hydrolysis agent, 2 parts hydrophobic agent, 2.5 parts nano zinc oxide, 4 parts N,N'-bis(β-naphthyl)-p-phenylenediamine, and 2 parts sulfur.

[0041] The anti-hydrolysis agent consists of 1 part pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] and 0.5 parts carbodiimide anti-hydrolysis agent.

[0042] The hydrophobic agent consists of 1.7 parts of polydimethylsiloxane and 0.3 parts of a mixture of perfluorooctyltriethoxysilane.

[0043] The preparation method of the modified EPDM rubber is as follows:

[0044] According to the formula of EPDM rubber: maleic anhydride: initiator: antioxidant: dispersant = 100:7:1:0.3:0.4, the antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid].

[0045] Set the initial temperature of the internal mixer to 85℃, add the above-mentioned weight proportions of EPDM rubber and plasticize for 3 minutes, then add the antioxidant and mix for 1 minute. Add maleic anhydride in 3 batches, mixing for 2 minutes after each addition. Raise the temperature of the internal mixer to 155℃, add dicumyl peroxide and zinc stearate and plasticize for 8 minutes. Transfer the rubber compound discharged from the internal mixer to a single-screw extruder with a discharge temperature of 160℃ to obtain 3mm modified EPDM rubber granules.

[0046] The preparation method of its hydrogenated nitrile butadiene rubber is as follows:

[0047] The ratio of nitrile rubber: triethylamine: antioxidant: Pd / C catalyst: rhodium-based catalyst is 100: 0.3: 0.4: 0.5: 1, and the antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid].

[0048] The above-mentioned nitrile rubber solution in parts by weight was transferred to a high-pressure reactor. Triethylamine and antioxidant were added and stirred. Nitrogen gas was introduced, and Pd / C catalyst was added. Rhodium-based catalyst was slowly added and stirred. After the nitrogen gas was turned off, hydrogen gas was introduced. The reactor was kept at a constant temperature and pressure of 2 MPa and 80 °C and stirred for activation. Then the temperature and pressure were increased to 8 MPa and 100 °C and hydrogenation was carried out for 6 hours. After the reaction was completed, the hydrogen gas was turned off and nitrogen gas was introduced. The solid product was taken out, purified to remove residual catalyst, washed and dried to obtain hydrogenated nitrile rubber.

[0049] The preparation method of its modified silica is as follows:

[0050] Silica and KH-570 silane coupling agent were added to a high-speed mixer at a ratio of 100:3 and mixed at 125°C and 1500 r / min for 20 min to ensure that the coupling agent completely coated the surface of the silica, thus obtaining modified silica.

[0051] The preparation method of its water-resistant rubber sealing ring is as follows:

[0052] S1. Raw material pretreatment: Modified EPDM rubber and hydrogenated nitrile rubber are preheated in an oven at 65℃ for 2 hours to obtain a substrate with a moisture content of less than 0.1%.

[0053] S2. Pre-dispersion of functional additives: Mix nano zinc oxide and anti-hydrolysis agent, grind to obtain functional additive masterbatch with a particle size of less than 5μm;

[0054] S3, Substrate Plasticizing: Set the initial temperature of the internal mixer to 80℃, first add fluororubber and the substrate obtained in S1 (modified EPDM rubber and hydrogenated nitrile rubber), plasticize for 3 minutes until the rubber compound softens, add polyester fiber, and mix for 2 minutes.

[0055] S4, Reinforcement: Raise the temperature of the internal mixer to 90℃, add modified silica in 3 batches with an interval of 1 minute between each batch, mix for 5 minutes, add hydrophobic agent and functional additive masterbatch obtained in S2 in sequence, mix for 3 minutes, discharge the glue, and control the discharge temperature below 110℃.

[0056] S5, Thin pass: Transfer to open mill, initially set the roller temperature to 50℃ and the roller gap to 2mm, add N,N'-bis(β-naphthyl)p-phenylenediamine, thin pass 5 times, then add sulfur, adjust the roller gap to 0.5mm, thin pass 8 times, let stand for 24h to obtain rubber compound;

[0057] S6. First stage of vulcanization: Transfer the rubber compound to the mold, set the temperature to 150℃, the pressure to 11MPa, and the vulcanization time to 8min, accounting for 40% of the total vulcanization time.

[0058] S7. Second stage vulcanization: The temperature is set at 170℃, the pressure at 18MPa, and the vulcanization time is 10min, accounting for 50% of the total vulcanization time.

[0059] S8. Third stage vulcanization: The temperature is set to 120℃, the pressure to 8MPa, and the vulcanization time to 2min, accounting for 10% of the total vulcanization time, to obtain the rubber ring.

[0060] S9. Boiling and surface activation treatment: The rubber ring obtained in S7 is soaked in deionized water at 90℃ for 2 hours to remove residual vulcanizing agents and small molecules, reducing extractables during later use. It is then naturally cooled to room temperature to avoid structural stress caused by sudden cooling. Low-temperature plasma treatment is then used with a power of 300W for 60 seconds to further improve the surface hydrophobicity and remove residual impurities on the surface, resulting in a water-resistant rubber sealing ring.

[0061] Example 2

[0062] The difference from Example 1 is that the hydrophobic agent is a mixture of 1.65 parts of polydimethylsiloxane and 0.35 parts of perfluorooctyltriethoxysilane.

[0063] Example 3

[0064] The difference from Example 1 is that the hydrophobic agent is a mixture of 1.6 parts of polydimethylsiloxane and 0.4 parts of perfluorooctyltriethoxysilane.

[0065] Example 4

[0066] The difference from Example 1 is that the hydrophobic agent is a mixture of 1.5 parts of polydimethylsiloxane and 0.5 parts of perfluorooctyltriethoxysilane.

[0067] Example 5

[0068] The difference from Embodiment 1 is that it includes the following weight distribution:

[0069] 65 parts modified EPDM rubber, 45 parts modified silica, 25 parts hydrogenated nitrile butadiene rubber, 3 parts polyester fiber, 1.5 parts anti-hydrolysis agent, 2 parts hydrophobic agent, 2.5 parts nano zinc oxide, 4 parts N,N'-bis(β-naphthyl)-p-phenylenediamine, and 2 parts sulfur.

[0070] Comparative Example 1

[0071] The difference from Embodiment 1 is that it includes the following weight distribution:

[0072] 65 parts EPDM rubber, 45 parts silica, 25 parts nitrile rubber, 2 parts hydrophobic agent, 4 parts N,N'-bis(β-naphthyl)-p-phenylenediamine, and 2 parts sulfur.

[0073] A method for preparing a rubber sealing ring, without modifying the EPDM rubber, silica, or nitrile rubber, includes the following steps:

[0074] S1. Raw material pretreatment: Preheat EPDM rubber and nitrile rubber in an oven at 65℃ for 2 hours to obtain a substrate with a moisture content of less than 0.1%;

[0075] S2, Substrate Plasticizing: Set the initial temperature of the internal mixer to 80℃, add the substrate (EPDM rubber and nitrile rubber) obtained in S1, and plasticize for 5 minutes;

[0076] S3, Reinforcement: Raise the temperature of the internal mixer to 90℃, add the silica in 3 batches with an interval of 1 minute between each batch, mix for 5 minutes, add the hydrophobic agent and mix for 3 minutes, then discharge the glue, and control the discharge temperature below 110℃.

[0077] S4, Thin pass: Transfer to open mill, initially set the roller temperature to 50℃ and the roller gap to 2mm, add N,N'-bis(β-naphthyl)p-phenylenediamine, thin pass 5 times, then add sulfur, adjust the roller gap to 0.5mm, thin pass 8 times, let stand for 24h to obtain rubber compound;

[0078] S5. Vulcanization: Transfer the rubber compound to the mold, set the temperature to 150℃, the pressure to 11MPa, and the vulcanization time to 20min to obtain the rubber sealing ring.

[0079] Test

[0080] The rubber sealing rings prepared in Examples 1-5 were subjected to actual seawater immersion environment simulation. The volume expansion rate, tensile strength retention rate, antimicrobial performance (antibacterial rate), water permeability, and hydrolytic aging resistance were periodically tested. The test results are shown in Table 1.

[0081] Table 1 Statistical analysis of performance test results

[0082]

[0083]

[0084] Therefore, the present invention employs the above-mentioned water-contaminated rubber sealing ring and its preparation method, which is suitable for freshwater and warm water scenarios, and has broad application prospects in ship sealing and sewage treatment equipment in seawater and industrial wastewater scenarios.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A water-resistant rubber sealing ring, characterized in that, Includes the following weight groups: Modified EPDM rubber 60-70 parts, modified silica 35-50 parts, hydrogenated nitrile butadiene rubber 20-30 parts, fluororubber 0-10 parts, polyester fiber 2-5 parts, anti-hydrolysis agent 0.5-3 parts, hydrophobic agent 1-3 parts, antimicrobial agent 2-4 parts, antioxidant 3-5 parts, sulfur 1-7 parts. The anti-hydrolysis agent is a mixture of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] and carbodiimide anti-hydrolysis agents; The hydrophobic agent is a mixture of polydimethylsiloxane and perfluorooctyltriethoxysilane; The antimicrobial agent is nano zinc oxide; The antioxidant is N,N'-bis(β-naphthyl)-p-phenylenediamine.

2. The water-resistant rubber sealing ring according to claim 1, characterized in that: The ratio of the tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] pentaerythritol ester to the carbodiimide antihydrolysis agent is 2:1, by mass.

3. The water-resistant rubber sealing ring according to claim 1, characterized in that: The ratio of polydimethylsiloxane to perfluorooctyltriethoxysilane is 6-3:1, by mass.

4. A method for preparing a water-resistant rubber sealing ring as described in any one of claims 1-3, characterized in that, Includes the following steps: S1. Raw material pretreatment: Modified EPDM rubber and hydrogenated nitrile rubber are preheated in an oven at 60-70℃ for 2-3 hours to obtain a substrate with a moisture content of less than 0.1%. S2. Pre-dispersion of functional additives: Mix nano zinc oxide and anti-hydrolysis agent, grind to obtain functional additive masterbatch with a particle size of less than 5μm; S3, Substrate Plasticizing: Set the initial temperature of the internal mixer to 80-90℃, first add fluororubber and the substrate obtained from S1, plasticize for 3-5 minutes until the rubber softens, add polyester fiber, and mix for 2-3 minutes; S4, Reinforcement: Raise the temperature of the internal mixer to 90-100℃, add modified silica in 2-3 batches with an interval of 1-3 minutes between each batch, mix for 5-7 minutes, add hydrophobic agent and functional additive masterbatch obtained in S2 in sequence, mix for 3-4 minutes, and then discharge the glue. S5, Thin pass: Transfer to open mill, initially set the roller temperature to 50-60℃ and the roller gap to 1-2mm, add N,N'-bis(β-naphthyl)p-phenylenediamine, thin pass 4-5 times, then add sulfur, adjust the roller gap to 0.5mm, thin pass 6-8 times, let stand for 12-24h to obtain rubber compound; S6, First stage of vulcanization: Transfer the rubber compound to the mold, set the temperature to 145-155℃, the pressure to 10-12MPa, and the vulcanization time to 6-8min; S7. Second stage vulcanization: Temperature set at 165-175℃, pressure at 15-18MPa, vulcanization time at 8-10min; S8, Third stage vulcanization: Temperature set at 115-125℃, pressure at 5-8MPa, vulcanization time at 2-3min, to obtain the rubber ring; S9. Boiling and surface activation treatment: The rubber ring obtained in S7 is immersed in deionized water at 80-90℃ for 2-3 hours, naturally cooled to room temperature, and then treated with low-temperature plasma to obtain a water-resistant rubber sealing ring.

5. The method for preparing a water-resistant rubber sealing ring according to claim 4, characterized in that, The preparation method of the modified EPDM rubber includes the following steps: According to the proportion, set the initial temperature of the internal mixer to 80-90℃, add EPDM rubber and plasticize for 3-5 minutes, then add antioxidant and mix for 0.5-1 minutes. Add maleic anhydride in 2-3 batches, mixing for 1.5-2.5 minutes after each addition. Raise the temperature of the internal mixer to 150-160℃, add initiator and dispersant and plasticize for 5-8 minutes. Transfer the rubber compound discharged from the internal mixer to a single-screw extruder with a discharge temperature of 160-170℃ to obtain modified EPDM rubber granules of 2-3 mm.

6. The method for preparing a water-resistant rubber sealing ring according to claim 5, characterized in that, The dispersant is zinc stearate, the initiator is dicumyl peroxide, and the antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], with a dosage ratio of EPDM rubber: maleic anhydride: initiator: antioxidant: dispersant = 100:7:1:0.3:0.4, by mass.

7. The method for preparing a water-resistant rubber sealing ring according to claim 4, characterized in that, The preparation method of the hydrogenated nitrile butadiene rubber includes the following steps: According to the proportion, the nitrile rubber solution was transferred to a high-pressure reactor, triethylamine and antioxidant were added and stirred, nitrogen gas was introduced, Pd / C catalyst was added, rhodium-based catalyst was slowly added and stirred, nitrogen gas was turned off and hydrogen gas was introduced, and the reaction was activated by stirring at a constant temperature and pressure of 2-3 MPa and 80-90℃. Then the temperature and pressure were increased to 8-12 MPa and 100-120℃ and hydrogenation was carried out for 6-10 hours. After the reaction was completed, hydrogen gas was turned off and nitrogen gas was introduced. The solid product was taken out, purified to remove residual catalyst, washed and dried to obtain hydrogenated nitrile rubber.

8. The method for preparing a water-resistant rubber sealing ring according to claim 7, characterized in that: The ratio of the nitrile rubber, the triethylamine, the antioxidant, the Pd / C catalyst, and the rhodium-based catalyst is 100:0.3:0.4:0.5:1, by mass.

9. The water-resistant rubber sealing ring and its preparation method according to claim 4, characterized in that: The preparation method of the modified silica includes the following steps: Add silica and KH-570 silane coupling agent to a high-speed mixer at a ratio of 100:3, and mix for 15-20 minutes at 120-130℃ and 1500 r / min to obtain modified silica.

10. The method for preparing a water-resistant rubber sealing ring according to claim 4, characterized in that: The low-temperature plasma treatment has a power of 300W and a duration of 30-60s.

Images