Union sealing ring for high-pressure pipeline and preparation method

Abstract

The invention provides a union sealing ring for a high-pressure pipeline and a preparation method, and belongs to the technical field of sealing washs.The sealing ring is prepared from 100 parts of nitrile rubber, 14-16 parts of ethylene propylene diene monomer, 30-40 parts of carbon black, 8-12 parts of hyperbranched modified acrylate colloid and 2-4 parts of magnesium oxide. The hyperbranched modified acrylate colloid is prepared by modifying acrylate with hydroxylated boron nitride nanosheets and then carrying out hyperbranched treatment, and the hyperbranched modified acrylate colloid is prepared from the following components in parts by weight: 3-7 parts of zinc oxide, 1-2 parts of an accelerant, 0.5-1 part of a vulcanization accelerator, 3-5 parts of a composite vulcanizing agent, 1-2 parts of an anti-aging agent and 0.5-1.5 parts of stearic acid. The prepared union sealing ring for the high-pressure pipeline has excellent temperature stability, high mechanical strength and sealing performance can be kept in a temperature change environment, and long-term stable operation of the high-pressure pipeline is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of sealing rings, and particularly relates to a union sealing ring for high-pressure pipelines and a preparation method thereof. Background Art

[0002] A union is a key component widely used in the connection of high-pressure pipelines, and its sealing performance directly affects the safety and stability of the pipelines. The sealing rings used for unions need to adapt to different working conditions, and the material selection of the sealing rings is directly related to the performance and quality of the pipelines for transporting high-pressure liquids.

[0003] Nitrile butadiene rubber (NBR), a copolymer formed by the polymerization of acrylonitrile and butadiene monomers, has low price and high pressure resistance. In addition, due to the high elasticity obtained from its cross-linked network structure, nitrile butadiene rubber is widely used in the field of high-pressure pipeline sealing. In the prior art, nitrile butadiene rubber sealing rings are sensitive to temperature. In a temperature-changing environment, the compression set is large and the mechanical strength decreases significantly, resulting in poor sealing effect and reduced durability of the sealing rings, and it is difficult to meet the requirements of long-term stable operation of high-pressure pipelines. Summary of the Invention

[0004] To solve the problems in the background art, the present invention provides a union sealing ring for high-pressure pipelines and a preparation method thereof. The obtained sealing ring can effectively adapt to temperature changes, has excellent temperature stability, can maintain high mechanical strength and sealing performance, and ensures the long-term stable operation of high-pressure pipelines.

[0005] To achieve the above object, the present invention provides the following technical solutions: A union sealing ring for high-pressure pipelines, by weight, the raw material composition of the sealing ring includes: 100 parts of nitrile butadiene rubber, 14 - 16 parts of ethylene propylene diene monomer rubber, 30 - 40 parts of carbon black, 8 - 12 parts of hyperbranched modified acrylate colloid, 2 - 4 parts of magnesium oxide, 3 - 7 parts of zinc oxide, 1 - 2 parts of accelerator, 0.5 - 1 part of vulcanization accelerator, 3 - 5 parts of composite vulcanizing agent, 1 - 2 parts of antioxidant, 0.5 - 1.5 parts of stearic acid; wherein the hyperbranched modified acrylate colloid is prepared by modifying acrylate with hydroxylated boron nitride nanosheets and then performing hyperbranched treatment.

[0006] Further, the preparation of the hyperbranched modified acrylate colloid includes the following steps: A1. Mix 1 part of hydroxylated boron nitride nanosheets and 2 - 3 parts of sodium hydroxide evenly, heat to 350 - 450 °C under nitrogen protection, keep warm for 2 - 4 h, cool to room temperature, add them to a high-pressure reactor containing 10 - 20 parts of deionized water, carry out hydrothermal reaction at 140 - 160 °C for 1 - 2 h, filter, wash, and dry to obtain hydroxylated boron nitride nanosheets. Add the hydroxylated boron nitride nanosheets to 20 - 30 parts of dimethyl sulfoxide and ultrasonicate for 10 - 20 min to obtain a dispersion of hydroxylated boron nitride nanosheets; A2. Add the dispersion of boron nitride nanosheets and acrylate monomers to the reactor, stir for 0.5 - 1.5 h, add benzoyl peroxide and dodecyl mercaptan, heat to 55 - 65 °C under nitrogen protection, and keep the reaction warm for 3 - 5 h to obtain boron nitride-modified acrylate, where the mass ratio of acrylate monomers, benzoyl peroxide, and dodecyl mercaptan is 100:0.3 - 1:2 - 4; A3. Add branched monomers, triphenylphosphine, and 2-ethylhexyl acrylate to the boron nitride-modified acrylate obtained in A2, raise the temperature to 120 - 130 °C, stir for 2 - 4 h, add 2,6-di-tert-butyl-p-cresol according to 0.05 - 0.1% by weight of the boron nitride-modified acrylate, and continue to stir for 0.5 - 1 h to obtain a hyperbranched modified acrylate colloid, where the mass ratio of boron nitride-modified acrylate, triphenylphosphine, and 2-ethylhexyl acrylate is 100:1 - 3:0.5 - 1.

[0007] Further, in step A2, the mass ratio of the dispersion of hydroxylated boron nitride nanosheets to acrylate monomers is 5:2 - 4.

[0008] Further, in step A3, the mass ratio of boron nitride-modified acrylate to branched monomers is 10:2 - 4.

[0009] Further, in step A2, the acrylate monomer is one or a mixture of two or more of ethyl acrylate, butyl acrylate, 2-hydroxyethyl acrylate, and 2-hydroxypropyl acrylate.

[0010] Further, in step A3, the branched monomer is one or a mixture of two or more of pentaerythritol triacrylate, pentaerythritol tetraacrylate, and dipentaerythritol hexaacrylate.

[0011] Further, the accelerator is one or a mixture of two of triallyl cyanurate and triallyl isocyanurate, and the vulcanization accelerator is one or a mixture of two of tetraethylthiuram disulfide and tetramethylthiuram disulfide.

[0012] Further, the antioxidant is one or a mixture of two of antioxidant RD and antioxidant 4020.

[0013] Furthermore, the composite vulcanizing agent is a mixture of sulfur and cumene hydroperoxide with a mass ratio of 1:3 - 5.

[0014] The present invention also provides a preparation method of a union seal ring for high-pressure pipelines, which is used to prepare the union seal ring for high-pressure pipelines in the above solution, and includes the following steps: S1. After mixing and plasticizing nitrile rubber, ethylene propylene diene monomer rubber and hyperbranched modified acrylate colloid, add them into a mixer together with zinc oxide, magnesium hydroxide, carbon black, stearic acid and antioxidant, and mix at room temperature for 20 - 40 min to obtain a mixed rubber; S2. Add the mixed rubber into an open mill and add a composite vulcanizing agent, a promoter and a vulcanization accelerator, mix at 70 - 80 °C for 5 - 10 min, discharge the rubber to obtain a mixed rubber; S3. Transfer the mixed rubber obtained in step S2 to a vulcanization device for vulcanization treatment. Among them, the vulcanization temperature in the vulcanization device is 145 - 165 °C, and the vulcanization time is 5 - 10 min to obtain vulcanized rubber; S4. Process the vulcanized rubber obtained in step S3 into a specified shape to obtain a union seal ring for high-pressure pipelines.

[0015] This application has the following beneficial effects: 1. The union seal ring for high-pressure pipelines provided by the present invention has a simple and efficient preparation process. The obtained seal ring has high mechanical strength and temperature stability. When used in an environment with temperature changes, the seal ring can maintain high mechanical strength and excellent sealing performance.

[0016] 2. In the preparation of the hyperbranched modified acrylate colloid, the introduction of hydroxyl groups increases the surface activity of boron nitride nanosheets, improves the dispersibility and compatibility of boron nitride nanosheets with polymers and other materials. Hydroxylated boron nitride nanosheets can improve the thermal conductivity of the material, enabling the internal heat of the material to be transferred in a timely and effective manner, avoiding the deterioration of compression set due to temperature changes. The hyperbranched treatment can improve the resilience of the material, enhance the compression set resistance of the material, and at the same time improve the compatibility of nitrile rubber and ethylene propylene diene monomer rubber, improve the dispersion ability and bonding performance between rubbers, enabling the seal ring material to maintain stable performance under extreme temperature differences, effectively coping with the challenges brought by thermal expansion and contraction, and improving the temperature adaptability of the seal ring.

[0017] 3. Hydroxylated boron nitride nanosheets have a two-dimensional sheet structure, a high specific surface area and surface activity. They can form a stable and dense three-dimensional network structure in hyperbranched materials, further improving the heat transfer performance and structural strength of the material. Through the combination of hydroxylation modification of boron nitride nanosheets and hyperbranched treatment, the temperature stability of the seal ring can be improved, and its sealing performance in high and low temperature environments can be further improved. Detailed embodiments

[0018] The present application will be further described in detail below in conjunction with embodiments.

[0019] Unless otherwise specified, the raw materials of the embodiments and comparative examples of the present application are all commercially available.

[0020] Example 1 A union seal ring for high-pressure pipelines is prepared from the following raw materials by weight: 100 parts of nitrile rubber, 15 parts of ethylene propylene diene monomer rubber, 35 parts of carbon black, 10 parts of hyperbranched modified acrylate colloid, 3 parts of magnesium oxide, 5 parts of zinc oxide, 1.5 parts of accelerator, 0.8 part of vulcanization accelerator, 4 parts of composite vulcanizing agent, 1.5 parts of antioxidant and 1.0 part of stearic acid. Among them, the accelerator is triallyl cyanurate, the vulcanization accelerator is tetraethylthiuram disulfide, the antioxidant is antioxidant RD, and the composite vulcanizing agent is a mixture of sulfur and cumene hydroperoxide with a mass ratio of 1:4.

[0021] The preparation of the hyperbranched modified acrylate colloid includes the following steps: A1. Mix 1 part of boron nitride nanosheets and 2.5 parts of sodium hydroxide evenly, heat to 400 °C under nitrogen protection, keep warm for 3 h, cool to room temperature, add them to a high-pressure reaction kettle containing 15 parts of deionized water, and carry out hydrothermal reaction at 150 °C for 1.5 h. Filter, wash and dry to obtain hydroxylated boron nitride nanosheets. Add the hydroxylated boron nitride nanosheets to 25 parts of dimethyl sulfoxide and ultrasonic for 15 min to obtain a hydroxylated boron nitride nanosheet dispersion; A2. Add the hydroxylated boron nitride nanosheet dispersion and acrylate monomer to the reaction kettle, stir for 1 h, add benzoyl peroxide and dodecyl mercaptan, heat to 60 °C under nitrogen protection, and keep warm for 4 hours to obtain boron nitride modified acrylate. The mass ratio of the acrylate monomer, benzoyl peroxide and dodecyl mercaptan is 100:0.5:3. The acrylate monomer is ethyl acrylate, and the mass ratio of the hydroxylated boron nitride nanosheet dispersion and the acrylate monomer is 5:3; A3. Add a branched monomer, triphenylphosphine and 2-ethylhexyl acrylate to the boron nitride modified acrylate obtained in A2, raise the temperature to 125 °C, stir for 3 hours, add 2,6-di-tert-butyl-p-cresol according to 0.1% by weight of the boron nitride modified acrylate, and continue to stir for 0.5 h to obtain a hyperbranched modified acrylate colloid. The mass ratio of the boron nitride modified acrylate, triphenylphosphine and 2-ethylhexyl acrylate is 100:2:0.8, and the mass ratio of the boron nitride modified acrylate and the branched monomer is 10:3. The branched monomer is pentaerythritol triacrylate; The union seal ring for high-pressure pipelines is prepared by the following steps: S1. Mix acrylonitrile-butadiene rubber, ethylene propylene diene monomer rubber and hyperbranched modified acrylate colloid, and then plastify them. After that, put them together with zinc oxide, magnesium hydroxide, carbon black, stearic acid and antioxidant into a mixer and knead at room temperature for 30 min to obtain kneaded rubber. S2. Add the kneaded rubber to an open mill, and add compound vulcanizing agent, accelerator and vulcanization accelerator. Knead at 75 °C for 10 min, then discharge the rubber to obtain kneaded compound. S3. Transfer the kneaded compound obtained in step S2 to a vulcanization device for vulcanization treatment. Among them, the vulcanization temperature in the vulcanization device is 155 °C and the vulcanization time is 8 min to obtain vulcanized rubber. S4. Process the vulcanized rubber obtained in step S3 into a specified shape to obtain a union seal ring for high-pressure pipeline.

[0022] Example 2 A union seal ring for high-pressure pipeline is prepared from the following raw materials by weight: 100 parts of acrylonitrile-butadiene rubber, 14 parts of ethylene propylene diene monomer rubber, 30 parts of carbon black, 8 parts of hyperbranched modified acrylate colloid, 2 parts of magnesium oxide, 3 parts of zinc oxide, 1 part of accelerator, 0.5 part of vulcanization accelerator, 3 parts of compound vulcanizing agent, 1 part of antioxidant and 0.5 part of stearic acid. Among them, the accelerator is triallyl isocyanurate, the vulcanization accelerator is tetramethyl thiuram disulfide, the antioxidant is antioxidant 4020, and the compound vulcanizing agent is a mixture of sulfur and cumene hydroperoxide with a mass ratio of 1:3.

[0023] The preparation of hyperbranched modified acrylate colloid includes the following steps: A1. Mix 1 part of boron nitride nanosheets and 2 parts of sodium hydroxide evenly, heat to 350 °C under nitrogen protection, keep warm for 4 h, cool to room temperature, add them to a high-pressure reactor containing 10 parts of deionized water, and carry out hydrothermal reaction at 140 °C for 2 h. Filter, wash and dry to obtain hydroxylated boron nitride nanosheets. Add the hydroxylated boron nitride nanosheets to 20 parts of dimethyl sulfoxide and ultrasonicate for 10 min to obtain a hydroxylated boron nitride nanosheet dispersion. A2. Add the hydroxylated boron nitride nanosheet dispersion and acrylate monomer to the reactor, stir for 0.5 h, add benzoyl peroxide and dodecyl mercaptan, heat to 55 °C under nitrogen protection, and keep warm for 5 h to obtain boron nitride modified acrylate. Among them, the mass ratio of acrylate monomer, benzoyl peroxide and dodecyl mercaptan is 100:0.3:2, the acrylate monomer is butyl acrylate, and the mass ratio of hydroxylated boron nitride nanosheet dispersion and acrylate monomer is 5:2. A3. Add a branched monomer, triphenylphosphine, and 2-ethylhexyl acrylate to the boron nitride-modified acrylate obtained in A2. Heat the mixture to 120 °C and stir for 4 hours. Add 2,6-di-tert-butyl-p-cresol according to 0.05% by weight of the boron nitride-modified acrylate, and continue stirring for 0.5 h to obtain a hyperbranched modified acrylate colloid. The mass ratio of the boron nitride-modified acrylate, triphenylphosphine, and 2-ethylhexyl acrylate is 100:1:0.5, and the mass ratio of the boron nitride-modified acrylate to the branched monomer is 10:2. The branched monomer is pentaerythritol tetraacrylate; The union nut seal ring for high-pressure pipelines is prepared by the following steps: S1. Mix and plastify nitrile rubber, ethylene propylene diene monomer rubber, and the hyperbranched modified acrylate colloid, and then put them together with zinc oxide, magnesium hydroxide, carbon black, stearic acid, and antioxidant into a mixer. Knead at room temperature for 20 min to obtain kneaded rubber; S2. Add the kneaded rubber to an open mill and add a compound vulcanizing agent, accelerator, and vulcanization accelerator. Knead at 70 °C for 10 min, discharge the rubber, and obtain kneaded rubber; S3. Transfer the kneaded rubber obtained in step S2 to a vulcanization device for vulcanization treatment. The vulcanization temperature in the vulcanization device is 145 °C, and the vulcanization time is 10 min to obtain vulcanized rubber; S4. Process the vulcanized rubber obtained in step S3 into a specified shape to obtain the union nut seal ring for high-pressure pipelines.

[0024] Example 3 A union nut seal ring for high-pressure pipelines is prepared from the following raw materials by weight: 100 parts of nitrile rubber, 16 parts of ethylene propylene diene monomer rubber, 40 parts of carbon black, 12 parts of hyperbranched modified acrylate colloid, 4 parts of magnesium oxide, 7 parts of zinc oxide, 2 parts of accelerator, 1 part of vulcanization accelerator, 5 parts of compound vulcanizing agent, 2 parts of antioxidant, and 1.5 parts of stearic acid. The accelerator is triallyl cyanurate, the vulcanization accelerator is tetraethylthiuram disulfide, the antioxidant is antioxidant RD, and the compound vulcanizing agent is a mixture of sulfur and cumene hydroperoxide with a mass ratio of 1:5.

[0025] The preparation of the hyperbranched modified acrylate colloid includes the following steps: A1. Mix 1 part of boron nitride nanosheets and 3 parts of sodium hydroxide evenly, heat to 450 °C under nitrogen protection, keep warm for 2 h, cool to room temperature, add to a high-pressure reaction kettle containing 20 parts of deionized water, carry out a hydrothermal reaction at 160 °C for 1 h, filter, wash, and dry to obtain hydroxylated boron nitride nanosheets. Add the hydroxylated boron nitride nanosheets to 30 parts of dimethyl sulfoxide and sonicate for 20 min to obtain a hydroxylated boron nitride nanosheet dispersion; A2. Add the hydroxylated boron nitride nanosheet dispersion and acrylate monomer to the reaction kettle, stir for 1.5 h, add benzoyl peroxide and dodecyl mercaptan, heat to 65 °C under nitrogen protection, and keep the temperature for 3 hours to obtain boron nitride-modified acrylate. The mass ratio of acrylate monomer, benzoyl peroxide and dodecyl mercaptan is 100:1:4. The acrylate monomer is 2-hydroxyethyl acrylate, and the mass ratio of hydroxylated boron nitride nanosheet dispersion to acrylate monomer is 5:4; A3. Add the branched monomer, triphenylphosphine and 2-ethylhexyl acrylate to the boron nitride-modified acrylate obtained in A2, raise the temperature to 130 °C, stir for 2 hours, add 2,6-di-tert-butyl-p-cresol according to 0.1% by weight of the boron nitride-modified acrylate, and continue to stir for 1 h to obtain a hyperbranched modified acrylate colloid. The mass ratio of boron nitride-modified acrylate, triphenylphosphine and 2-ethylhexyl acrylate is 100:3:1, and the mass ratio of boron nitride-modified acrylate to branched monomer is 10:4. The branched monomer is dipentaerythritol hexaacrylate; The union nut seal ring for high-pressure pipelines is prepared by the following steps: S1. Mix and plasticize nitrile rubber, ethylene propylene diene monomer rubber and hyperbranched modified acrylate colloid, and then put them into a kneader together with zinc oxide, magnesium hydroxide, carbon black, stearic acid and antioxidant, and knead at room temperature for 40 min to obtain kneaded rubber; S2. Add the kneaded rubber to an open mill, add a compound vulcanizing agent, a promoter and a vulcanization accelerator, knead at 80 °C for 5 min, and discharge the rubber to obtain kneaded rubber; S3. Transfer the kneaded rubber obtained in step S2 to a vulcanization device for vulcanization treatment. The vulcanization temperature in the vulcanization device is 165 °C and the vulcanization time is 5 min to obtain vulcanized rubber; S4. Process the vulcanized rubber obtained in step S3 into a specified shape to obtain the union nut seal ring for high-pressure pipelines.

[0026] Example 4 A union nut seal ring for high-pressure pipelines is prepared from the following raw materials by weight: 100 parts of nitrile rubber, 14 parts of ethylene propylene diene monomer rubber, 40 parts of carbon black, 12 parts of hyperbranched modified acrylate colloid, 2 parts of magnesium oxide, 7 parts of zinc oxide, 1 part of promoter, 1 part of vulcanization accelerator, 3 parts of compound vulcanizing agent, 1 part of antioxidant and 1.5 parts of stearic acid. The promoter is triallyl cyanurate, the vulcanization accelerator is tetramethyl thiuram disulfide, the antioxidant is antioxidant RD, and the compound vulcanizing agent is a mixture of sulfur and cumene hydroperoxide with a mass ratio of 1:3.

[0027] The preparation of the hyperbranched modified acrylate colloid includes the following steps: A1. Mix 1 part of boron nitride nanosheets and 3 parts of sodium hydroxide evenly, heat to 450 °C under nitrogen protection, keep the temperature for 2 h, cool to room temperature, add it to a high-pressure reactor containing 10 parts of deionized water, and carry out hydrothermal reaction at 160 °C for 1 h. Filter, wash, and dry to obtain hydroxylated boron nitride nanosheets. Add the hydroxylated boron nitride nanosheets to 20 parts of dimethyl sulfoxide and ultrasonicate for 20 min to obtain a hydroxylated boron nitride nanosheet dispersion; A2. Add the hydroxylated boron nitride nanosheet dispersion and acrylate monomer to the reaction kettle, stir for 0.5 h, add benzoyl peroxide and dodecyl mercaptan, heat to 65 °C under nitrogen protection, and keep the temperature for 3 hours to obtain boron nitride-modified acrylate. The mass ratio of acrylate monomer, benzoyl peroxide and dodecyl mercaptan is 100:1:2. The acrylate monomer is hydroxypropyl acrylate, and the mass ratio of hydroxylated boron nitride nanosheet dispersion and acrylate monomer is 5:2; A3. Add a branched monomer, triphenylphosphine and 2-ethylhexyl acrylate to the boron nitride-modified acrylate obtained in A2, raise the temperature to 120 °C, and stir for 4 hours. Add 2,6-di-tert-butyl-p-cresol according to 0.1% by weight of the boron nitride-modified acrylate, and continue to stir for 0.5 h to obtain a hyperbranched modified acrylate colloid. The mass ratio of boron nitride-modified acrylate, triphenylphosphine and 2-ethylhexyl acrylate is 100:2:1, and the mass ratio of boron nitride-modified acrylate and branched monomer is 10:3. The branched monomer is pentaerythritol triacrylate; The union nut seal ring for high-pressure pipelines is prepared by the following steps: S1. Mix and plasticize nitrile rubber, ethylene propylene diene monomer rubber and hyperbranched modified acrylate colloid, and then put them into a mixer together with zinc oxide, magnesium hydroxide, carbon black, stearic acid and antioxidant, and mix at room temperature for 20 min to obtain a mixed rubber; S2. Add the mixed rubber to an open mill and add a compound vulcanizing agent, accelerator and vulcanization accelerator, mix at 80 °C for 5 min, and discharge the rubber to obtain a mixed rubber; S3. Transfer the mixed rubber obtained in step S2 to a vulcanizing device for vulcanization treatment. The vulcanization temperature in the vulcanizing device is 145 °C and the vulcanization time is 10 min to obtain vulcanized rubber; S4. Process the vulcanized rubber obtained in step S3 into a specified shape to obtain the union nut seal ring for high-pressure pipelines.

[0028] Example 5 A union nut sealing ring for high-pressure pipelines is prepared from the following raw materials by weight: 100 parts of nitrile rubber, 16 parts of ethylene propylene diene monomer rubber, 30 parts of carbon black, 12 parts of hyperbranched modified acrylate colloid, 4 parts of magnesium oxide, 3 parts of zinc oxide, 1 part of accelerator, 0.5 part of vulcanization accelerator, 5 parts of compound vulcanizing agent, 1 part of antioxidant and 0.5 part of stearic acid. The accelerator is triallyl isocyanurate, the vulcanization accelerator is tetraethylthiuram disulfide, the antioxidant is antioxidant 4020, and the compound vulcanizing agent is a mixture of sulfur and cumene hydroperoxide with a mass ratio of 1:5.

[0029] The preparation of the hyperbranched modified acrylate colloid includes the following steps: A1. Mix 1 part of boron nitride nanosheets and 2.5 parts of sodium hydroxide evenly, heat to 350 °C under nitrogen protection, keep warm for 4 h, cool to room temperature, add them into a high-pressure reactor containing 10 parts of deionized water, carry out hydrothermal reaction at 160 °C for 1 h, filter, wash and dry to obtain hydroxylated boron nitride nanosheets. Add the hydroxylated boron nitride nanosheets into 30 parts of dimethyl sulfoxide and ultrasonicate for 20 min to obtain a hydroxylated boron nitride nanosheet dispersion; A2. Add the hydroxylated boron nitride nanosheet dispersion and acrylate monomer into the reactor, stir for 1 h, add benzoyl peroxide and dodecyl mercaptan, heat to 65 °C under nitrogen protection, keep warm and react for 3 h to obtain boron nitride modified acrylate. The mass ratio of the acrylate monomer, benzoyl peroxide and dodecyl mercaptan is 100:0.5:2. The acrylate monomer is butyl acrylate, and the mass ratio of the hydroxylated boron nitride nanosheet dispersion and the acrylate monomer is 5:4; A3. Add a branched monomer, triphenylphosphine and 2-ethylhexyl acrylate to the boron nitride modified acrylate obtained in A2, raise the temperature to 120 °C, stir for 4 h, add 2,6-di-tert-butyl-p-cresol according to 0.05% by weight of the boron nitride modified acrylate, and continue to stir for 0.5 h to obtain a hyperbranched modified acrylate colloid. The mass ratio of the boron nitride modified acrylate, triphenylphosphine and 2-ethylhexyl acrylate is 100:3:0.5, the mass ratio of the boron nitride modified acrylate and the branched monomer is 10:4, and the branched monomer is pentaerythritol triacrylate, pentaerythritol tetraacrylate and dipentaerythritol hexaacrylate; The union nut sealing ring for high-pressure pipelines is prepared by the following steps: S1. Mix and plasticate nitrile rubber, ethylene propylene diene monomer rubber and hyperbranched modified acrylate colloid, and then put them together with zinc oxide, magnesium hydroxide, carbon black, stearic acid and antioxidant into a mixer and mix at room temperature for 20 min to obtain a mixed rubber; S2. Add the mixed rubber into an open mill and add the compound vulcanizing agent, accelerator and vulcanization accelerator, mix at 70 °C for 10 min, discharge the rubber to obtain a mixed rubber; S3. Transfer the kneaded rubber obtained in step S2 to a vulcanization device for vulcanization treatment, where the vulcanization temperature in the vulcanization device is 145°C and the vulcanization time is 5 min to obtain vulcanized rubber; S4. Process the vulcanized rubber obtained in step S3 into a specified shape to obtain a union seal ring for high-pressure pipelines.

[0030] Comparative Example 1 The difference between this comparative example and Example 1 is only that in the preparation of the hyperbranched modified acrylate colloid, the acrylate was not modified with hydroxylated boron nitride nanosheets, as follows: A1. Add dimethyl sulfoxide and acrylate monomer to a reaction kettle, stir for 1 h, add benzoyl peroxide and dodecyl mercaptan, heat to 60°C under nitrogen protection, and keep the temperature for reaction for 4 hours to obtain boron nitride modified acrylate, where the mass ratio of acrylate monomer, benzoyl peroxide and dodecyl mercaptan is 100:0.5:3, the acrylate monomer is methyl methacrylate, and the mass ratio of dimethyl sulfoxide and acrylate monomer is 5:3; A2. Add a branched monomer, triphenylphosphine and 2-ethylhexyl acrylate to the boron nitride modified acrylate obtained in A1, raise the temperature to 125°C, stir for 3 hours, add 2,6-di-tert-butyl-p-cresol according to 0.1% by weight of the boron nitride modified acrylate, and continue to stir for 0.5 h to obtain a hyperbranched modified acrylate colloid, where the mass ratio of boron nitride modified acrylate, triphenylphosphine and 2-ethylhexyl acrylate is 100:2:0.8, and the mass ratio of boron nitride modified acrylate and branched monomer is 10:3, and the branched monomer is pentaerythritol triacrylate.

[0031] Comparative Example 2 The difference between this comparative example and Example 1 is only that in the preparation of the hyperbranched modified acrylate colloid, the boron nitride modified acrylate was not hyperbranched, as follows: A1. Mix 1 part of boron nitride nanosheets and 2.5 parts of sodium hydroxide evenly, heat to 400°C under nitrogen protection, keep the temperature for 3 h, cool to room temperature, add to a high-pressure reaction kettle containing 15 parts of deionized water, and carry out hydrothermal reaction at 150°C for 1.5 h, filter, wash and dry to obtain hydroxylated boron nitride nanosheets, and add the hydroxylated boron nitride nanosheets to 25 parts of dimethyl sulfoxide and ultrasonicate for 15 min to obtain a hydroxylated boron nitride nanosheet dispersion; A2. Add the hydroxylated boron nitride nanosheet dispersion and acrylate monomer to the reaction kettle, stir for 1 h, add benzoyl peroxide and dodecyl mercaptan, heat to 60 °C under nitrogen protection, and keep the temperature for reaction for 4 h to obtain boron nitride-modified acrylate. The mass ratio of acrylate monomer, benzoyl peroxide and dodecyl mercaptan is 100:0.5:3. The acrylate monomer is methyl methacrylate, and the mass ratio of hydroxylated boron nitride nanosheet dispersion to acrylate monomer is 5:3; A3. Add triphenylphosphine and 2-ethylhexyl acrylate to the boron nitride-modified acrylate obtained in A2, raise the temperature to 125 °C, stir for 3 h, add 2,6-di-tert-butyl-p-cresol according to 0.1% by weight of the boron nitride-modified acrylate, and continue stirring for 0.5 h to obtain a hyperbranched modified acrylate colloid. The mass ratio of boron nitride-modified acrylate, triphenylphosphine and 2-ethylhexyl acrylate is 100:2:0.8.

[0032] Comparative Example 3 The difference between this comparative example and Example 1 is only that in the preparation of the hyperbranched modified acrylate colloid, the acrylate was not modified with hydroxylated boron nitride nanosheets, and at the same time, the boron nitride-modified acrylate was not hyperbranched. The specific steps are as follows: A1. Add acrylate monomer to the reaction kettle, stir for 1 h, add benzoyl peroxide and dodecyl mercaptan, heat to 60 °C under nitrogen protection, and keep the temperature for reaction for 4 h to obtain boron nitride-modified acrylate; A2. Add triphenylphosphine and 2-ethylhexyl acrylate to the boron nitride-modified acrylate obtained in A1, raise the temperature to 125 °C, stir for 3 h, add 2,6-di-tert-butyl-p-cresol according to 0.1% by weight of the boron nitride-modified acrylate, and continue stirring for 0.5 h to obtain a hyperbranched modified acrylate colloid. The mass ratio of boron nitride-modified acrylate, triphenylphosphine and 2-ethylhexyl acrylate is 100:2:0.8, and the mass ratio of boron nitride-modified acrylate to branching monomer is 10:3. The branching monomer is pentaerythritol triacrylate; Effect verification Perform performance tests on the seal ring materials prepared in Examples 1-5 and Comparative Examples 1-3. The specific test results are shown in Table 1: Tensile strength test: Conduct the tensile strength test in accordance with 《GB / T 528-2009》, and test the initial tensile strength of the test specimen at a tensile speed of 500 mm / min.

[0033] Tensile strength retention rate: Place the tensile test specimen in a low-temperature chamber at -20°C for 20 h, take it out and place it at room temperature for 4 h, then put it in an oven at 120°C for 20 h, take it out and place it at room temperature for 4 h. This is one cycle. Conduct 3 such cycles, test the tensile strength of the specimen after high and low temperature treatment, and calculate the tensile strength retention rate.

[0034] Compression set: Test the compression set after high and low temperature treatment according to GB / T 1683-2018. Place the compression device with the specimen installed in a low-temperature chamber at -20°C for 20 h, take it out and place it at room temperature for 4 h, then put it in a high-temperature chamber at 120°C for 20 h, take it out and place it at room temperature for 4 h. This is one cycle. Conduct 3 such cycles, and then test the compression set of the specimen.

[0035] Table 1 Result analysis Analysis of Examples 1-5 and Comparative Examples 1-3, and combined with the data in Table 1 shows that the initial tensile strength of the sealing ring prepared by the present invention is above 16.6 MPa, indicating that the sealing ring has high mechanical strength. At the same time, after the sealing ring undergoes high and low temperature treatment, the tensile strength retention rate of the sealing ring can reach above 85.7%, and the compression set is below 20.3%, indicating that the sealing ring has high temperature adaptability. In a high and low temperature change environment, the sealing ring can maintain high mechanical strength and excellent sealing performance.

[0036] Analysis of Comparative Examples 1-3 and Example 1 shows that in the preparation of hyperbranched modified acrylate colloid, the hydroxylation of boron nitride nanosheets modification and hyperbranched treatment of acrylate can improve the temperature stability of the sealing ring, increase the tensile strength retention rate, and reduce the compression set. At the same time, the combined use of hydroxylation of boron nitride nanosheets modification and hyperbranched treatment can produce a synergistic effect, which can further reduce the compression set and greatly improve the sealing performance of the sealing ring in a temperature change environment.

[0037] In addition, it should be noted that, among the various specific technical features described in the above specific embodiments, without conflict, they can be combined in any suitable way. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0038] In addition, any combination can be made between various different embodiments of the present invention, as long as it does not violate the idea of the present invention, it should also be regarded as the content disclosed by the present invention.

Claims

1. A union seal ring for high-pressure pipelines, characterized in that, It is prepared from the following raw materials in parts by weight: 100 parts of nitrile rubber, 14 - 16 parts of ethylene propylene diene monomer rubber, 30 - 40 parts of carbon black, 8 - 12 parts of hyperbranched modified acrylate colloid, 2 - 4 parts of magnesium oxide, 3 - 7 parts of zinc oxide, 1 - 2 parts of accelerator, 0.5 - 1 part of vulcanization accelerator, 3 - 5 parts of compound vulcanizing agent, 1 - 2 parts of antioxidant, and 0.5 - 1.5 parts of stearic acid; Among them, the hyperbranched modified acrylate colloid is prepared by modifying acrylate with hydroxylated boron nitride nanosheets and then performing hyperbranched treatment.

2. The union seal ring for high-pressure pipelines according to claim 1, characterized in that, The preparation of the hyperbranched modified acrylate colloid includes the following steps: A1. Mix 1 part of hydroxylated boron nitride nanosheets and 2 - 3 parts of sodium hydroxide evenly, heat to 350 - 450 °C under nitrogen protection, keep warm for 2 - 4 h, cool to room temperature, add to a high-pressure reaction kettle containing 10 - 20 parts of deionized water, carry out hydrothermal reaction at 140 - 160 °C for 1 - 2 h, filter, wash, and dry to obtain hydroxylated boron nitride nanosheets. Add the hydroxylated boron nitride nanosheets to 20 - 30 parts of dimethyl sulfoxide and ultrasonicate for 10 - 20 min to obtain a hydroxylated boron nitride nanosheet dispersion; A2. Add the boron nitride nanosheet dispersion and acrylate monomer to the reaction kettle, stir for 0.5 - 1.5 h, add benzoyl peroxide and dodecyl mercaptan, heat to 55 - 65 °C under nitrogen protection, and keep warm for 3 - 5 hours to obtain boron nitride modified acrylate, where the mass ratio of acrylate monomer, benzoyl peroxide, and dodecyl mercaptan is 100:0.3 - 1:2 - 4; A3. Add a branching monomer, triphenylphosphine, and 2 - ethylhexyl acrylate to the boron nitride modified acrylate obtained in A2, raise the temperature to 120 - 130 °C, stir for 2 - 4 hours, add 2,6 - di - tert - butyl - p - cresol according to 0.05 - 0.1% by weight of the boron nitride modified acrylate, and continue to stir for 0.5 - 1 h to obtain a hyperbranched modified acrylate colloid, where the mass ratio of boron nitride modified acrylate, triphenylphosphine, and 2 - ethylhexyl acrylate is 100:1 - 3:0.5 - 1.

3. The union seal ring for high-pressure pipelines according to claim 2, characterized in that, In step A2, the mass ratio of the hydroxylated boron nitride nanosheet dispersion to the acrylate monomer is 5:2 - 4.

4. The union seal ring for high-pressure pipelines according to claim 2, characterized in that, In step A3, the mass ratio of the boron nitride modified acrylate to the branching monomer is 10:2 - 4.

5. The union seal ring for high-pressure pipeline according to claim 2, wherein In step A2, the acrylate monomer is one or a mixture of two or more of ethyl acrylate, butyl acrylate, 2 - hydroxyethyl acrylate, and 2 - hydroxypropyl acrylate.

6. The union seal ring for high-pressure pipeline according to claim 2, wherein In step A3, the branching monomer is one or a mixture of two or more of pentaerythritol triacrylate, pentaerythritol tetraacrylate, and dipentaerythritol hexaacrylate.

7. The union seal ring for high-pressure pipelines according to claim 1, characterized in that, The accelerator is one or a mixture of two of triallyl cyanurate and triallyl isocyanurate, and the vulcanization accelerator is one or a mixture of two of tetraethyl thiuram disulfide and tetramethyl thiuram disulfide.

8. The union seal ring for high-pressure pipeline according to claim 1, characterized in that, The antioxidant is one or a mixture of two of antioxidant RD and antioxidant 4020.

9. The union seal ring for high-pressure pipelines according to claim 1, wherein The compound vulcanizing agent is a mixture of sulfur and cumene hydroperoxide with a mass ratio of 1:3 - 5.

10. A preparation method of a union seal ring for a high-pressure pipeline, which is used to prepare the union seal ring for a high-pressure pipeline according to any one of claims 1-9, and is characterized in that, It includes the following steps: S1. After mixing and plasticizing nitrile rubber, ethylene propylene diene monomer rubber and hyperbranched modified acrylate colloid, put them into an internal mixer together with zinc oxide, magnesium hydroxide, carbon black, stearic acid and antioxidant, and mix at room temperature for 20 - 40 min to obtain the internal mixer rubber; S2. Add the internal mixer rubber to an open mill and add a compound vulcanizing agent, a promoter and a vulcanization accelerator, mix at 70 - 80 °C for 5 - 10 min, and discharge the rubber to obtain the mixed rubber; S3. Transfer the internal mixer rubber obtained in step S2 to a vulcanization device for vulcanization treatment, wherein the vulcanization temperature in the vulcanization device is 145 - 165 °C and the vulcanization time is 5 - 10 min to obtain the vulcanized rubber; S4. Process the vulcanized rubber obtained in step S3 into a specified shape to obtain a union seal ring for high-pressure pipelines.

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