Oil-resistant rotary rubber core and preparation method thereof

Abstract

The invention discloses an oil-resistant rotary rubber core and a preparation method thereof, and belongs to the technical field of preparation of blowout preventer protection parts for well drilling. The preparation method comprises the following steps: mixing a mixed rubber matrix, carbon black modified polyacrylate raw rubber, a vulcanizing agent, a vulcanization accelerator and an anti-aging agent, and performing high-temperature banburying to obtain a mixture; and vulcanizing the mixture to obtain the rotary rubber core. Carbon black is subjected to surface modification to be connected to a monomer of polyacrylate rubber through a chemical bond, then carbon black modified polyacrylate raw rubber is obtained through polymerization, and finally, the carbon black modified polyacrylate raw rubber is subjected to mixing and cross-linking reaction with a mixed rubber matrix, a vulcanizing agent, a vulcanization accelerator and an anti-aging agent to obtain the modified polyacrylate rubber. The rotary rubber core with oil resistance and good mechanical property is obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of the preparation of blowout preventer protection parts for drilling, and particularly relates to an oil-resistant rotary rubber core and a preparation method thereof. Background Technique

[0002] Underbalanced drilling technology is a drilling technology that can improve drilling exploration and efficiency, and is one of the essential technologies in oil and gas resource development. So-called underbalanced drilling means that during the drilling process, the circulating pressure of the drilling fluid is lower than the pore pressure of the formation, keeping a slight overflow at the bottom of the well, allowing the formation fluid to flow into the wellbore, and it can be circulated to the ground and effectively controlled on the ground. This technology is called underbalanced pressure drilling technology. Compared with conventional drilling technology, the main advantages of underbalanced drilling are that it can reduce formation damage and increase the productivity of oil wells. For exploration wells, implementing underbalanced drilling can produce good productivity shows and provide conditions for correctly evaluating reservoirs. In addition, using underbalanced drilling can also increase the mechanical drilling rate and reduce or prevent differential sticking. The equipment required for implementing underbalanced drilling mainly includes: wellhead control equipment and surface treatment equipment. Among them, the wellhead control equipment mainly refers to the rotating control head or the rotating blowout preventer, which together with the original annular blowout preventer, ram blowout preventer, four-way joint, etc. form the wellhead blowout preventer group. Its function is to control the pressure of the oil and gas well, prevent, monitor, and control accidents, and ensure the safety of drilling personnel, drilling equipment, and oil and gas wells. The performance of the rotating control head or the rotating blowout preventer will directly affect the success or failure of the underbalanced construction of the oil and gas well. Once a failure occurs during the construction process, serious drilling accidents such as blowout may occur. One of the key components of the rotating control head or the rotating blowout preventer is the rotary rubber core, which is mainly used in the rotating blowout preventer to achieve the sealing and protection of the wellhead. Its functions include: (1) Sealing function: During the drilling process, the rotary rubber core can effectively cooperate closely with the drill string to form a good seal to prevent the leakage of well fluid and gas; (2) Withstand high pressure: The rotary rubber core can work normally under high pressure conditions to ensure that the blowout preventer can be closed in time when a blowout occurs and protect the operation safety; (3) Adapt to rotation: Since the drill string needs to rotate during the drilling process, the design of the rotary rubber core enables it to maintain good sealing performance in the rotating state and avoid seal failure caused by rotation. The mud medium acting on the rotary rubber core is a mixture composed of oil, gas, water, drill cuttings, and high molecular compounds, containing abrasive fine particles, which requires the rotary rubber core to have good oil resistance, wear resistance, and relatively high strength, etc.

[0003] Patent CN112480497A discloses a composition for preparing a rubber material, a rubber material, a preparation method thereof, and a blowout preventer. The composition of this invention uses nitrile rubber, a modified resin, silica, a vulcanization activator, a vulcanizing agent, and a vulcanization accelerator as raw materials. The modified resin modified by a silane coupling agent can combine with silica. The double bonds contained in the modified resin undergo a vulcanization cross-linking reaction, and cross-linking reactions occur between the modified resins to form a rigid resin cross-linking network. Cross-linking reactions occur between the modified resin and the nitrile rubber to form an interpenetrating cross-linking network, which can effectively increase the hardness and modulus of the rubber, and at the same time improve the oil resistance and heat swelling resistance.

[0004] Patent CN104530508A discloses a core material for a rubber and a preparation method thereof. This invention uses nitrile rubber, high abrasion furnace black, semi-reinforcing furnace black, graphene composite material, ultrafine fluidized powder, stearic acid, dioctyl phthalate, dibutyl phthalate, a promoter, and an antioxidant as raw materials. By using the ultrafine fluidized powder and the graphene composite material obtained after modification, the uniform dispersion of graphene is achieved, and the abrasion resistance and hardness of the core are improved.

[0005] Patent CN115716949A discloses an oil-resistant core material for a rubber, an oil-resistant core for a rubber, a preparation method thereof, and an application. This invention uses a rubber matrix, carbon black, a vulcanizing agent, an antioxidant, a promoter, a plasticizer, a lubricant, and a heat-conducting material as raw materials, so that the prepared core for a rubber has good oil resistance, abrasion resistance, and other properties.

[0006] The rotary core for a rubber used in the drilling process needs to have oil resistance. The above-mentioned inventions all use nitrile rubber with excellent oil resistance as the matrix. However, due to the poor mechanical properties of nitrile rubber, in actual use, it is often necessary to improve its mechanical properties by additionally adding reinforcing fillers such as carbon black and silica. However, due to reasons such as the fine particle size, large specific surface area, and easy electrostatic attraction of the reinforcing fillers, the reinforcing fillers are prone to agglomeration and uneven distribution, resulting in poor improvement of mechanical properties, and it is necessary to strictly control the preparation conditions and addition ratios.

[0007] Therefore, it is of great significance to design a rotary core for a rubber that can improve the uniform dispersion of the reinforcing filler to achieve oil resistance and good mechanical properties. Summary of the Invention

[0008] In view of the deficiencies of the prior art, the present invention solves the technical problems raised in the background art by surface-modifying carbon black, making it chemically bonded to the monomers of polyacrylate rubber, then obtaining carbon black-modified polyacrylate raw rubber through polymerization, and finally mixing and cross-linking with a mixed rubber matrix, a vulcanizing agent, a vulcanization accelerator, and an antioxidant to obtain a rotary core for a rubber. Specifically, the technical solution of the present invention includes the following content:

[0009] One of the objectives of the present invention is to provide a preparation method for an oil-resistant rotary rubber core. The preparation method includes the following steps:

[0010] 87 to 92 parts by weight of a mixed rubber matrix, 54 to 63 parts by weight of carbon black-modified polyacrylate raw rubber, 1 to 2.5 parts by weight of a vulcanizing agent, 0.6 to 1 part by weight of a vulcanization accelerator, and 4 to 6 parts by weight of an antioxidant are mixed and then kneaded at 110°C to 120°C for 8 min to 12 min to obtain a mixture;

[0011] The mixture is subjected to a primary vulcanization treatment at a temperature of 170°C to 180°C for 10 min to 12 min, and then placed in a temperature environment of 150°C to 160°C for a secondary vulcanization treatment for 2 h to 3 h to obtain the rotary rubber core.

[0012] Further, the mixed rubber matrix is composed of nitrile rubber and hydrogenated nitrile rubber in a weight ratio of 1:1.

[0013] Further, the acrylonitrile content of the nitrile rubber is 32% to 33%, and the acrylonitrile content in the hydrogenated nitrile rubber is 36% to 42%.

[0014] Further, the preparation method of the carbon black-modified polyacrylate raw rubber includes the following steps:

[0015] Carbon black and nitric acid solution are mixed and dispersed in a weight ratio of 1 to 2:10 to 20, and then heated to 90°C to 100°C and reacted for 15 h to 20 h to obtain carboxyl-modified carbon black;

[0016] The carboxyl-modified carbon black, glycol derivative, dicyclohexylcarbodiimide, and 4-dimethylaminopyridine are mixed in a weight ratio of 1:2 to 3:3 to 4:0.5 to 0.8 and reacted in a temperature environment of 20°C to 25°C for 20 h to 24 h to obtain hydroxyl-modified carbon black;

[0017] The hydroxyl-modified carbon black, acrylic acid derivative, dicyclohexylcarbodiimide, and 4-dimethylaminopyridine are mixed in a weight ratio of 1:2 to 3:4 to 5:0.8 to 1 and reacted in a temperature environment of 20°C to 25°C for 20 h to 24 h to obtain acrylic acid derivative-modified carbon black;

[0018] The acrylic acid derivative-modified carbon black, methyl acrylate, ethyl acrylate, water-soluble emulsifier, and deionized water are mixed and stirred in a weight ratio of 1 to 2:10 to 15:10 to 15:0.1 to 0.5:68 to 78 to form a mixed emulsion. The mixed emulsion is mixed with a radical initiator and heated to 60°C to 70°C and reacted for 3 h to 5 h, and then a polymerization inhibitor is added and the reaction is controlled at 30°C to 40°C for 20 min to 30 min to obtain the carbon black-modified polyacrylate raw rubber.

[0019] Furthermore, the mass concentration of the nitric acid solution is 50% - 60%.

[0020] Furthermore, the diol derivative includes ethylene glycol, 1,2 - propylene glycol or 1,3 - propylene glycol.

[0021] Furthermore, the acrylic acid derivative includes acrylic acid or methacrylic acid.

[0022] Furthermore, the water - soluble emulsifier includes sodium dodecyl sulfate or sodium dodecyl sulfonate.

[0023] Furthermore, the radical initiator is composed of an equal amount combination of ammonium persulfate and sodium bisulfite or an equal amount combination of potassium persulfate and sodium bisulfite.

[0024] Furthermore, the polymerization inhibitor includes N,N - diethylhydroxylamine or N - isopropylhydroxylamine.

[0025] Furthermore, the weight ratio of the mixed emulsion: radical initiator: polymerization inhibitor is 1: 0.01 - 0.05: 0.01 - 0.02.

[0026] Furthermore, the vulcanizing agent includes sulfur or dicumyl peroxide.

[0027] Furthermore, the vulcanization accelerator includes tetramethylthiuram disulfide, 2 - mercaptobenzothiazole or N - cyclohexyl - 2 - benzothiazolesulfenamide.

[0028] Furthermore, the antioxidant includes antioxidant 4020, antioxidant 445 or antioxidant 2246.

[0029] The second object of the present invention is to provide a rotary rubber core prepared by the preparation method of a rotary rubber core with oil resistance.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] In the present invention, the reinforcing filler carbon black is subjected to oxidation treatment to obtain functional groups carboxyl groups on its surface, and then condensed and esterified with glycol derivatives, so that functional groups hydroxyl groups are loaded on the surface of the carbon black, and then hydroxyl-modified carbon black is obtained. Then, through an esterification reaction, the hydroxyl-modified carbon black and an acrylic acid derivative are condensed through the carboxyl group and the hydroxyl group, and the carbon-carbon double bond in the structure of the acrylic acid derivative is introduced onto the surface of the carbon black to obtain acrylic acid derivative-modified carbon black with a carbon-carbon double bond functional group. Then, the acrylic acid derivative-modified carbon black is subjected to a polymerization reaction with methyl acrylate and ethyl acrylate under the action of a radical initiator, so that the carbon black is introduced into the polyacrylate raw rubber through a chemical reaction to obtain carbon black-modified polyacrylate raw rubber. Compared with the adverse effect that directly adding carbon black easily causes agglomeration, the modified carbon black is dispersed in the polyacrylate raw rubber through a chemical reaction, which not only enhances the dispersibility of the carbon black in the polyacrylate raw rubber, but also improves the binding force with the polyacrylate raw rubber. Finally, it is crosslinked with nitrile rubber and hydrogenated nitrile rubber containing a high content of acrylonitrile through a vulcanization system. By utilizing the characteristic that a high content of acrylonitrile in nitrile rubber and hydrogenated nitrile rubber can improve the oil resistance, through the synergistic cooperation of carbon black-modified polyacrylate raw rubber, nitrile rubber and hydrogenated nitrile rubber, while further improving the oil resistance of the rubber, the mechanical properties of the rubber are improved, so that the finally prepared rotary rubber core not only has good oil resistance, but also has good toughness, wear resistance and tensile strength. Detailed Embodiments

[0032] The technical solutions of the present invention will be clearly and completely described below through the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present invention.

[0033] Unless otherwise specified, the raw materials and reagents used in the present invention below are all commercially available products or can be prepared by known methods.

[0034] The nitrile rubber was purchased from Zhenjiang South Imperial Chemical Co., Ltd.;

[0035] The hydrogenated nitrile rubber was purchased from Shanghai Zannan Technology Co., Ltd.

[0036] Preparation Example 1:

[0037] The preparation of carbon black-modified polyacrylate raw rubber specifically includes the following process:

[0038] Mix 10 parts by weight of carbon black and 100 parts by weight of a nitric acid solution with a mass concentration of 50% in a reaction flask. Subsequently, continuously introduce nitrogen into the reaction flask for 10 min to 15 min to completely expel the air in the reaction flask. Then place the reaction flask in an ultrasonic cleaner and disperse it with an ultrasonic power of 200 W for 20 min. Subsequently, place it in an oil bath at 90 °C and heat it for reaction for 15 h. After the reaction is completed, naturally cool it to room temperature, then filter and separate to collect the particles, and repeatedly rinse the particles with deionized water until the pH of the rinsing water reaches neutral. Then place the particles in a vacuum drying oven at 60 °C and dry them to a constant weight to obtain carboxyl-modified carbon black.

[0039] Weigh 1 part by weight of carboxyl-modified carbon black, disperse it evenly in anhydrous dichloromethane solution, then add 2 parts by weight of ethylene glycol, 3 parts by weight of dicyclohexylcarbodiimide, and 0.5 part by weight of 4-dimethylaminopyridine and mix. In a temperature environment of 20 °C, stir and react at a rotation speed of 200 r / min for 20 h. After the reaction is completed, filter and separate the liquid and solid particles. First, rinse the solid particles with ethanol, then with acetone, and finally with deionized water. After rinsing, place them in a vacuum drying oven at 60 °C and dry them to a constant weight to obtain hydroxyl-modified carbon black.

[0040] Take 1 part by weight of hydroxyl-modified carbon black, 2 parts by weight of acrylic acid, 4 parts by weight of dicyclohexylcarbodiimide, and 0.8 part by weight of 4-dimethylaminopyridine and mix. In a temperature environment of 20 °C, stir and react at a rotation speed of 200 r / min for 20 h. After the reaction is completed, filter and separate, and rinse successively with acetone and deionized water, then place it in a vacuum drying oven at 60 °C and dry it to a constant weight to obtain acrylic acid-modified carbon black.

[0041] Mix 1 part by weight of acrylic acid-modified carbon black, 10 parts by weight of methyl acrylate, 10 parts by weight of ethyl acrylate, 0.1 part by weight of sodium dodecyl sulfate, and 68 parts by weight of deionized water in a reaction flask and stir until homogeneous to obtain a mixed emulsion. Replace the air in the reaction flask with nitrogen. Subsequently, add 0.891 part by weight of a radical initiator (composed of an equal amount combination of ammonium persulfate and sodium bisulfite) to the mixed emulsion and stir evenly. Then raise the temperature to 60 °C and stir and react at a rotation speed of 400 r / min for 3 h. After the reaction is completed, lower the temperature to 30 °C, then add 0.891 part by weight of N,N-diethylhydroxylamine and stir and react for 20 min. Finally, lower the temperature to room temperature and stop stirring. After centrifugal filtration and separation, obtain a precipitate. Place the precipitate in a drying oven at 70 °C and dry it for 10 h to obtain carbon black-modified polyacrylate raw rubber.

[0042] Preparation Example 2:

[0043] The preparation of carbon black-modified polyacrylate raw rubber specifically includes the following process:

[0044] Mix 12 parts by weight of carbon black and 120 parts by weight of nitric acid solution with a mass concentration of 50% in a reaction flask. Subsequently, continuously introduce nitrogen into the reaction flask for 10 min to 15 min to completely expel the air in the reaction flask. Then place the reaction flask in an ultrasonic cleaner and disperse it with an ultrasonic power of 220 W for 21 min. Subsequently, place it in an oil bath at 90 °C and heat it for reaction for 16 h. After the reaction is completed, naturally cool it to room temperature, then filter and separate to collect the particles, and repeatedly rinse the particles with deionized water until the pH of the rinsing water reaches neutral. Then place the particles in a vacuum drying oven at 60 °C and dry them to a constant weight to obtain carboxyl-modified carbon black.

[0045] Weigh 1 part by weight of carboxyl-modified carbon black and disperse it evenly in anhydrous dichloromethane solution. Subsequently, add 2.2 parts by weight of ethylene glycol, 3 parts by weight of dicyclohexylcarbodiimide, and 0.6 part by weight of 4-dimethylaminopyridine and mix. In a temperature environment of 20 °C, stir and react at a speed of 200 r / min for 20 h. After the reaction is completed, filter and separate the liquid and solid particles. First, rinse the solid particles with ethanol, then with acetone, and finally with deionized water. After rinsing, place them in a vacuum drying oven at 60 °C and dry them to a constant weight to obtain hydroxyl-modified carbon black.

[0046] Take 1 part by weight of hydroxyl-modified carbon black, 2.2 parts by weight of acrylic acid, 4 parts by weight of dicyclohexylcarbodiimide, and 0.8 part by weight of 4-dimethylaminopyridine and mix. In a temperature environment of 20 °C, stir and react at a speed of 220 r / min for 20 h. After the reaction is completed, filter and separate and rinse successively with acetone and deionized water, and then place it in a vacuum drying oven at 60 °C and dry it to a constant weight to obtain acrylic acid-modified carbon black.

[0047] Mix 1 part by weight of acrylic acid-modified carbon black, 11 parts by weight of methyl acrylate, 11 parts by weight of ethyl acrylate, 0.2 part by weight of sodium dodecyl sulfate, and 70 parts by weight of deionized water in a reaction flask and stir until homogeneous to obtain a mixed emulsion. Replace the air in the reaction flask with nitrogen. Subsequently, add 1.864 parts by weight of a radical initiator (composed of an equal amount combination of ammonium persulfate and sodium bisulfite) to the mixed emulsion and stir evenly. Then raise the temperature to 62 °C and stir and react at a speed of 400 r / min for 3 h. After the reaction is completed, cool the temperature to 30 °C, then add 0.932 part by weight of N,N-diethylhydroxylamine and stir and react for 22 min. Finally, lower the temperature to room temperature and stop stirring. After centrifugal filtration and separation, obtain a precipitate, and place the precipitate in a drying oven at 70 °C and dry it for 10 h to obtain carbon black-modified polyacrylate raw rubber.

[0048] Preparation Example 3:

[0049] The preparation of carbon black-modified polyacrylate raw rubber specifically includes the following process:

[0050] Mix 14 parts by weight of carbon black and 140 parts by weight of nitric acid solution with a mass concentration of 55% in a reaction flask. Subsequently, continuously introduce nitrogen into the reaction flask for 10 min to 15 min to completely expel the air in the reaction flask. Then place the reaction flask in an ultrasonic cleaner and disperse it with an ultrasonic power of 240 W for 22 min. Subsequently, place it in an oil bath at 95 °C and heat it for reaction for 17 h. After the reaction is completed, naturally cool it to room temperature, then filter and separate to collect the particles, and repeatedly rinse the particles with deionized water until the pH of the rinsing water reaches neutral. Then place the particles in a vacuum drying oven at 60 °C and dry them to constant weight to obtain carboxyl-modified carbon black.

[0051] Weigh 1 part by weight of carboxyl-modified carbon black and disperse it evenly in anhydrous dichloromethane solution. Subsequently, add 2.4 parts by weight of 1,2-propanediol, 3.5 parts by weight of dicyclohexylcarbodiimide, and 0.6 part by weight of 4-dimethylaminopyridine and mix. In a temperature environment of 20 °C, stir and react at a speed of 250 r / min for 22 h. After the reaction is completed, filter and separate the liquid and solid particles. First, rinse the solid particles with ethanol, then with acetone, and finally with deionized water. After rinsing, place them in a vacuum drying oven at 60 °C and dry them to constant weight to obtain hydroxyl-modified carbon black.

[0052] Take 1 part by weight of hydroxyl-modified carbon black, 2.4 parts by weight of acrylic acid, 4.5 parts by weight of dicyclohexylcarbodiimide, and 0.9 part by weight of 4-dimethylaminopyridine and mix. In a temperature environment of 20 °C, stir and react at a speed of 240 r / min for 22 h. After the reaction is completed, filter and separate and rinse successively with acetone and deionized water, and then place it in a vacuum drying oven at 60 °C and dry it to constant weight to obtain acrylic acid-modified carbon black.

[0053] Mix 1 part by weight of acrylic acid-modified carbon black, 12 parts by weight of methyl acrylate, 12 parts by weight of ethyl acrylate, 0.3 part by weight of sodium dodecyl sulfate, and 72 parts by weight of deionized water in a reaction flask and stir until homogeneous to obtain a mixed emulsion. Replace the air in the reaction flask with nitrogen. Subsequently, add 2.919 parts by weight of a radical initiator (composed of an equal amount combination of ammonium persulfate and sodium bisulfite) to the mixed emulsion and stir evenly. Then raise the temperature to 64 °C and stir and react at a speed of 450 r / min for 4 h. After the reaction is completed, cool the temperature to 35 °C, then add 0.973 part by weight of N,N-diethylhydroxylamine and stir and react for 24 min. Finally, lower the temperature to room temperature and stop stirring. After centrifugal filtration and separation, obtain a precipitate. Place the precipitate in a drying oven at 70 °C and dry it for 11 h to obtain carbon black-modified polyacrylate raw rubber.

[0054] Preparation Example 4:

[0055] The preparation of carbon black-modified polyacrylate raw rubber specifically includes the following process:

[0056] Mix 16 parts by weight of carbon black and 160 parts by weight of nitric acid solution with a mass concentration of 55% in a reaction flask. Subsequently, continuously introduce nitrogen into the reaction flask for 10 min to 15 min to completely expel the air in the reaction flask. Then place the reaction flask in an ultrasonic cleaner and disperse it with an ultrasonic power of 260 W for 23 min. Subsequently, place it in an oil bath at 95 °C and heat it for 18 h. After the reaction is completed, naturally cool it to room temperature, then filter and separate to collect the particles, and repeatedly rinse the particles with deionized water until the pH of the rinsing water reaches neutral. Then place the particles in a vacuum drying oven at 60 °C and dry them to a constant weight to obtain carboxyl-modified carbon black.

[0057] Weigh 1 part by weight of carboxyl-modified carbon black, disperse it evenly in anhydrous dichloromethane solution, then add 2.6 parts by weight of 1,2-propanediol, 3.5 parts by weight of dicyclohexylcarbodiimide, and 0.7 part by weight of 4-dimethylaminopyridine and mix. In a temperature environment of 25 °C, stir and react at a speed of 250 r / min for 22 h. After the reaction is completed, filter and separate the liquid and solid particles. First, rinse the solid particles with ethanol, then with acetone, and finally with deionized water. After rinsing, place them in a vacuum drying oven at 60 °C and dry them to a constant weight to obtain hydroxyl-modified carbon black.

[0058] Take 1 part by weight of hydroxyl-modified carbon black, 2.6 parts by weight of methacrylic acid, 4.5 parts by weight of dicyclohexylcarbodiimide, and 0.9 part by weight of 4-dimethylaminopyridine and mix. In a temperature environment of 25 °C, stir and react at a speed of 260 r / min for 22 h. After the reaction is completed, filter and separate, and rinse successively with acetone and deionized water, then place it in a vacuum drying oven at 60 °C and dry it to a constant weight to obtain methacrylic acid-modified carbon black.

[0059] Mix 2 parts by weight of methacrylic acid-modified carbon black, 13 parts by weight of methyl acrylate, 13 parts by weight of ethyl acrylate, 0.3 part by weight of sodium dodecyl sulfate, and 74 parts by weight of deionized water in a reaction flask and stir until uniform to obtain a mixed emulsion. Replace the air in the reaction flask with nitrogen. Subsequently, add 4.092 parts by weight of a radical initiator (composed of an equal combination of potassium persulfate and sodium bisulfite) to the mixed emulsion and stir evenly. Then raise the temperature to 66 °C and stir and react at a speed of 450 r / min for 4 h. After the reaction is completed, lower the temperature to 35 °C, then add 2.046 parts by weight of N-isopropylhydroxylamine and stir and react for 26 min. Finally, lower it to room temperature and stop stirring. After centrifugal filtration and separation, obtain a precipitate, and place the precipitate in a drying oven at 70 °C and dry it for 11 h to obtain carbon black-modified polyacrylate raw rubber.

[0060] Preparation Example 5:

[0061] The preparation of carbon black-modified polyacrylate raw rubber specifically includes the following process:

[0062] 18 parts by weight of carbon black and 180 parts by weight of nitric acid solution with a mass concentration of 60% were mixed together in a reaction flask. Subsequently, nitrogen gas was continuously introduced into the reaction flask for 10 - 15 minutes to completely expel the air in the reaction flask. Then the reaction flask was placed in an ultrasonic cleaner and dispersed with an ultrasonic power of 280 W for 24 minutes. Subsequently, it was placed in an oil bath at 100 °C and heated for reaction for 19 hours. After the reaction was completed, it was naturally cooled to room temperature, and then the particles were collected by filtration and separation. The particles were repeatedly rinsed with deionized water until the pH of the rinsing water reached neutral. Then the particles were placed in a vacuum drying oven at 60 °C and dried to a constant weight to obtain carboxyl - modified carbon black.

[0063] Weigh 1 part by weight of carboxyl - modified carbon black and disperse it evenly in anhydrous dichloromethane solution. Subsequently, 2.8 parts by weight of 1,3 - propanediol, 4 parts by weight of dicyclohexylcarbodiimide, and 0.7 part by weight of 4 - dimethylaminopyridine were added and mixed. In a temperature environment of 25 °C, the mixture was stirred and reacted at a rotation speed of 300 r / min for 24 hours. After the reaction was completed, the liquid and solid particles were separated by filtration. The solid particles were first rinsed with ethanol, then with acetone, and finally with deionized water. After rinsing, they were placed in a vacuum drying oven at 60 °C and dried to a constant weight to obtain hydroxyl - modified carbon black.

[0064] Take 1 part by weight of hydroxyl - modified carbon black, 2.8 parts by weight of methacrylic acid, 5 parts by weight of dicyclohexylcarbodiimide, and 1 part by weight of 4 - dimethylaminopyridine and mix them. In a temperature environment of 25 °C, the mixture was stirred and reacted at a rotation speed of 280 r / min for 24 hours. After the reaction was completed, it was filtered and separated and rinsed successively with acetone and deionized water, and then placed in a vacuum drying oven at 60 °C and dried to a constant weight to obtain methacrylic - acid - modified carbon black.

[0065] Mix 2 parts by weight of methacrylic - acid - modified carbon black, 14 parts by weight of methyl acrylate, 14 parts by weight of ethyl acrylate, 0.4 part by weight of sodium dodecyl sulfonate, and 76 parts by weight of deionized water in a reaction flask and stir until homogeneous to obtain a mixed emulsion. The air in the reaction flask was replaced with nitrogen gas. Subsequently, 5.32 parts by weight of a radical initiator (composed of an equal amount combination of potassium persulfate and sodium bisulfite) was added to the mixed emulsion and stirred evenly. Then the temperature was raised to 68 °C, and the mixture was stirred and reacted at a rotation speed of 500 r / min for 5 hours. After the reaction was completed, the temperature was lowered to 40 °C, and 2.128 parts by weight of N - isopropylhydroxylamine was added and stirred for reaction for 28 minutes. Finally, it was cooled to room temperature and stirring was stopped. The precipitate was obtained by centrifugal filtration separation, and the precipitate was placed in a drying oven at 70 °C and dried for 12 hours to obtain carbon - black - modified polyacrylate raw rubber.

[0066] Preparation Example 6:

[0067] The preparation of carbon - black - modified polyacrylate raw rubber specifically includes the following process:

[0068] Mix 20 parts by weight of carbon black and 200 parts by weight of a nitric acid solution with a mass concentration of 60% in a reaction flask. Subsequently, continuously introduce nitrogen into the reaction flask for 10 min to 15 min to completely expel the air in the reaction flask. Then place the reaction flask in an ultrasonic cleaner and disperse it with an ultrasonic power of 300 W for 25 min. Subsequently, place it in an oil bath at 100 °C and heat it for reaction for 20 h. After the reaction is completed, naturally cool it to room temperature, then filter and separate to collect the particles, and repeatedly rinse the particles with deionized water until the pH of the rinsing water reaches neutral. Then place the particles in a vacuum drying oven at 60 °C and dry them to a constant weight to obtain carboxyl-modified carbon black.

[0069] Weigh 1 part by weight of carboxyl-modified carbon black and disperse it evenly in anhydrous dichloromethane solution. Subsequently, add 3 parts by weight of 1,3-propanediol, 4 parts by weight of dicyclohexylcarbodiimide, and 0.8 part by weight of 4-dimethylaminopyridine and mix. In a temperature environment of 25 °C, stir and react at a speed of 300 r / min for 24 h. After the reaction is completed, filter and separate the liquid and solid particles. First, rinse the solid particles with ethanol, then with acetone, and finally with deionized water. After rinsing, place them in a vacuum drying oven at 60 °C and dry them to a constant weight to obtain hydroxyl-modified carbon black.

[0070] Take 1 part by weight of hydroxyl-modified carbon black, 3 parts by weight of methacrylic acid, 5 parts by weight of dicyclohexylcarbodiimide, and 1 part by weight of 4-dimethylaminopyridine and mix. In a temperature environment of 25 °C, stir and react at a speed of 300 r / min for 24 h. After the reaction is completed, filter and separate and rinse successively with acetone and deionized water, and then place it in a vacuum drying oven at 60 °C and dry it to a constant weight to obtain methacrylic acid-modified carbon black.

[0071] Mix 2 parts by weight of methacrylic acid-modified carbon black, 15 parts by weight of methyl acrylate, 15 parts by weight of ethyl acrylate, 0.5 part by weight of sodium dodecylsulfonate, and 78 parts by weight of deionized water in a reaction flask and stir until homogeneous to obtain a mixed emulsion. Replace the air in the reaction flask with nitrogen. Subsequently, add 5.525 parts by weight of a radical initiator (composed of an equal amount combination of potassium persulfate and sodium bisulfite) to the mixed emulsion and stir evenly. Then raise the temperature to 70 °C and stir and react at a speed of 500 r / min for 5 h. After the reaction is completed, lower the temperature to 40 °C, then add 2.21 parts by weight of N-isopropylhydroxylamine and stir and react for 30 min. Finally, lower the temperature to room temperature and stop stirring. After centrifugal filtration and separation, obtain a precipitate. Place the precipitate in a drying oven at 70 °C and dry it for 12 h to obtain carbon black-modified polyacrylate raw rubber.

[0072] Preparation Example 7:

[0073] The preparation of carbon black-modified polyacrylate raw rubber specifically includes the following process:

[0074] Increase the mass concentration of nitric acid in Preparation Example 6 to 80%, raise the reaction temperature of the oil bath to 110 °C, and extend the heating duration to 24 h. Keep the other conditions the same as those in Preparation Example 6.

[0075] Preparation Example 8:

[0076] The preparation of carbon black-modified polyacrylate raw rubber specifically includes the following process:

[0077] Replace methacrylic acid in Preparation Example 6 with 10-undecenoic acid, and keep the other conditions the same as those in Preparation Example 6.

[0078] Preparation Example 9:

[0079] The preparation of silica white-modified polyacrylate raw rubber specifically includes the following process:

[0080] Take 1 part by weight of silica white, 2.8 parts by weight of methacrylic acid, 5 parts by weight of dicyclohexylcarbodiimide, and 1 part by weight of 4-dimethylaminopyridine and mix them. Stir and react at a speed of 280 r / min for 24 h in a temperature environment of 25 °C. After the reaction, filter and separate, and wash successively with acetone and deionized water, then place it in a vacuum drying oven at 60 °C and dry to constant weight to obtain methacrylic acid-modified silica white.

[0081] Mix 2 parts by weight of methacrylic acid-modified silica white, 14 parts by weight of methyl acrylate, 14 parts by weight of ethyl acrylate, 0.4 part by weight of sodium dodecylsulfonate, and 76 parts by weight of deionized water in a reaction flask and stir until homogeneous to obtain a mixed emulsion. Replace the air in the reaction flask with nitrogen, then add 5.32 parts by weight of a radical initiator (composed of an equal amount combination of potassium persulfate and sodium bisulfite) to the mixed emulsion and stir evenly, then raise the temperature to 68 °C and stir and react at a speed of 500 r / min for 5 h. After the reaction, cool down to 40 °C, then add 2.128 parts by weight of N-isopropylhydroxylamine and stir and react for 28 min. Finally, lower the temperature to room temperature and stop stirring. Separate the precipitate by centrifugal filtration, and place the precipitate in a drying oven at 70 °C and dry for 12 h to obtain silica white-modified polyacrylate raw rubber.

[0082] Example 1:

[0083] The preparation of an oil-resistant rotary rubber core specifically includes the following process:

[0084] Mix 87 parts by weight of a mixed rubber matrix (composed of 43.5 parts by weight of nitrile rubber with 32% acrylonitrile mass fraction and 43.5 parts by weight of hydrogenated nitrile rubber with 36% acrylonitrile mass fraction), 54 parts by weight of the carbon black-modified polyacrylate raw rubber obtained in Preparation Example 1, 1 part by weight of sulfur, 0.6 part by weight of tetramethylthiuram disulfide, and 4 parts by weight of antioxidant 4020 into a kneader. Heat up to 110 °C and knead for 8 min to obtain a mixture. Subsequently, put the mixture into a flat vulcanizer and heat up to 170 °C for the first-stage vulcanization treatment for 10 min, then put it into a drying oven at 150 °C for the second-stage vulcanization for 2 h to obtain a vulcanized rubber. Pour the vulcanized rubber into a mold and cool it to form an oil-resistant rotating rubber core.

[0085] Example 2:

[0086] The preparation of an oil-resistant rotating rubber core specifically includes the following process:

[0087] Mix 88 parts by weight of a mixed rubber matrix (composed of 44 parts by weight of nitrile rubber with 32% acrylonitrile mass fraction and 44 parts by weight of hydrogenated nitrile rubber with 36% acrylonitrile mass fraction), 56 parts by weight of the carbon black-modified polyacrylate raw rubber obtained in Preparation Example 2, 1.4 parts by weight of sulfur, 0.7 part by weight of tetramethylthiuram disulfide, and 4 parts by weight of antioxidant 4020 into a kneader. Heat up to 110 °C and knead for 8 min to obtain a mixture. Subsequently, put the mixture into a flat vulcanizer and heat up to 170 °C for the first-stage vulcanization treatment for 10 min, then put it into a drying oven at 150 °C for the second-stage vulcanization for 2 h to obtain a vulcanized rubber. Pour the vulcanized rubber into a mold and cool it to form an oil-resistant rotating rubber core.

[0088] Example 3:

[0089] The preparation of an oil-resistant rotating rubber core specifically includes the following process:

[0090] Mix 89 parts by weight of a mixed rubber matrix (composed of 44.5 parts by weight of nitrile rubber with 32% acrylonitrile mass fraction and 44.5 parts by weight of hydrogenated nitrile rubber with 39% acrylonitrile mass fraction), 58 parts by weight of the carbon black-modified polyacrylate raw rubber obtained in Preparation Example 3, 1.8 parts by weight of sulfur, 0.8 part by weight of 2-mercaptobenzothiazole, and 5 parts by weight of antioxidant 445 into a kneader. Heat up to 115 °C and knead for 10 min to obtain a mixture. Subsequently, put the mixture into a flat vulcanizer and heat up to 175 °C for the first-stage vulcanization treatment for 11 min, then put it into a drying oven at 155 °C for the second-stage vulcanization for 2 h to obtain a vulcanized rubber. Pour the vulcanized rubber into a mold and cool it to form an oil-resistant rotating rubber core.

[0091] Example 4:

[0092] Preparation of an oil-resistant rotary rubber core, specifically including the following process:

[0093] Add 90 parts by weight of a mixed rubber matrix (composed of 45 parts by weight of nitrile rubber with an acrylonitrile mass fraction of 33% and 45 parts by weight of hydrogenated nitrile rubber with an acrylonitrile mass fraction of 39%), 60 parts by weight of the carbon black-modified polyacrylate raw rubber obtained in Preparation Example 4, 2 parts by weight of dicumyl peroxide, 0.9 part by weight of 2-mercaptobenzothiazole, and 5 parts by weight of antioxidant 445 into a kneader, heat up to 115°C and knead for 10 min to obtain a mixture. Subsequently, put the mixture into a flat vulcanizer and heat up to 175°C for the first-stage vulcanization treatment for 11 min, then put it into a drying oven at 155°C for the second-stage vulcanization for 3 h to obtain a vulcanized rubber. Pour the vulcanized rubber into a mold and cool it to form an oil-resistant rotary rubber core.

[0094] Example 5:

[0095] Preparation of an oil-resistant rotary rubber core, specifically including the following process:

[0096] Add 91 parts by weight of a mixed rubber matrix (composed of 45.5 parts by weight of nitrile rubber with an acrylonitrile mass fraction of 33% and 45.5 parts by weight of hydrogenated nitrile rubber with an acrylonitrile mass fraction of 42%), 62 parts by weight of the carbon black-modified polyacrylate raw rubber obtained in Preparation Example 5, 2.3 parts by weight of dicumyl peroxide, 1 part by weight of N-cyclohexyl-2-benzothiazole sulfenamide, and 6 parts by weight of antioxidant 2246 into a kneader, heat up to 120°C and knead for 12 min to obtain a mixture. Subsequently, put the mixture into a flat vulcanizer and heat up to 180°C for the first-stage vulcanization treatment for 12 min, then put it into a drying oven at 160°C for the second-stage vulcanization for 3 h to obtain a vulcanized rubber. Pour the vulcanized rubber into a mold and cool it to form an oil-resistant rotary rubber core.

[0097] Example 6:

[0098] Preparation of an oil-resistant rotary rubber core, specifically including the following process:

[0099] Add 92 parts by weight of a mixed rubber matrix (composed of 46 parts by weight of nitrile rubber with an acrylonitrile mass fraction of 33% and 46 parts by weight of hydrogenated nitrile rubber with an acrylonitrile mass fraction of 42%), 63 parts by weight of the carbon black-modified polyacrylate raw rubber obtained in Preparation Example 6, 2.5 parts by weight of dicumyl peroxide, 1 part by weight of N-cyclohexyl-2-benzothiazole sulfenamide, and 6 parts by weight of antioxidant 2246 into a kneader, heat up to 120°C and knead for 12 min to obtain a mixture. Subsequently, put the mixture into a flat vulcanizer and heat up to 180°C for the first-stage vulcanization treatment for 12 min, then put it into a drying oven at 160°C for the second-stage vulcanization for 3 h to obtain a vulcanized rubber. Pour the vulcanized rubber into a mold and cool it to form an oil-resistant rotary rubber core.

[0100] Comparative Example 1:

[0101] The preparation of an oil-resistant rotary rubber core specifically includes the following process:

[0102] Replace the carbon black-modified polyacrylate raw rubber in Example 6 with the carbon black-modified polyacrylate raw rubber obtained in Preparation Example 7, and keep the other conditions the same as those in Example 6.

[0103] Comparative Example 2:

[0104] The preparation of an oil-resistant rotary rubber core specifically includes the following process:

[0105] Replace the carbon black-modified polyacrylate raw rubber in Example 6 with the carbon black-modified polyacrylate raw rubber obtained in Preparation Example 8, and keep the other conditions the same as those in Example 6.

[0106] Comparative Example 3:

[0107] The preparation of an oil-resistant rotary rubber core specifically includes the following process:

[0108] Replace the carbon black-modified polyacrylate raw rubber in Example 6 with the silica-modified polyacrylate raw rubber obtained in Preparation Example 9, and keep the other conditions the same as those in Example 6.

[0109] According to the standards of "GB / T 531.1-2008 Rubber, vulcanized or thermoplastic - Determination of indentation hardness", "GB / T 528-2009 Rubber, vulcanized or thermoplastic - Determination of tensile stress-strain properties", "GB / T 1690-2010 Rubber, vulcanized or thermoplastic - Resistance to liquids" and "GB / T 1689-214 Rubber, vulcanized - Determination of abrasion resistance", the performance tests were carried out on the rotary rubber cores prepared in Examples 1-6 and the rotary rubber cores prepared in Comparative Examples 1-3. The results are shown in the following table.

[0110]

[0111] It can be seen from the above test results that:

[0112] (1) In the present invention, carbon black is introduced into the polyacrylate raw rubber through a chemical reaction to obtain a carbon black-modified polyacrylate raw rubber, which has a good improvement in the dispersion performance of carbon black. Then, it is co-vulcanized and crosslinked with nitrile rubber and hydrogenated nitrile rubber. Through the synergistic cooperation among the three, not only does the prepared rotary rubber core retain the good oil resistance of nitrile rubber and hydrogenated nitrile rubber, but also has a good improvement in mechanical properties such as hardness and tensile strength and abrasion resistance.

[0113] (2) It can be seen from the analysis of Comparative Example 1 that due to the treatment with high-concentration nitric acid and oxidation for a long time, it may cause a large decomposition effect on the carbon skeleton on the surface of carbon black, resulting in great changes in the properties of carbon black, poor improvement in the mechanical properties of the prepared rotary rubber core, and poor wear resistance.

[0114] (3) It can be seen from the analysis of Comparative Example 2 that 10-undecenoic acid has a longer saturated carbon chain structure in terms of spatial structure compared with methacrylic acid. The longer saturated carbon chain structure increases the rotational freedom within the molecule, which in turn makes the relative movement between polymer segments easier to achieve, resulting in a further increase in the flexibility of the prepared rotary rubber core, a further decrease in the tensile strength, being not conducive to improving the hardness of the rotary rubber core, showing poor wear resistance, and a slight decrease in oil resistance.

[0115] (4) It can be seen from the analysis of Comparative Example 3 that when using silica, although the silica surface has a silanol structure and there is no need to introduce hydroxyl groups through oxidation and re-condensation, the silanol groups on the silica surface can self-condense and crosslink, resulting in fewer hydroxyl groups reacting with the carboxyl functional group in methacrylic acid, leading to poor dispersion modification effect of silica, and thus poor mechanical properties and wear resistance of the prepared rotary rubber core.

[0116] The above-described embodiments have detailed the technical solutions and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. A preparation method of an oil-resistant rotary rubber core, characterized in that The preparation method comprises the following steps: 87 to 92 parts by weight of a mixed rubber matrix, 54 to 63 parts by weight of carbon black-modified polyacrylate raw rubber, 1 to 2.5 parts by weight of a vulcanizing agent, 0.6 to 1 part by weight of a vulcanization accelerator, and 4 to 6 parts by weight of an antioxidant are mixed and then kneaded at 110°C to 120°C for 8 min to 12 min to obtain a mixture; The mixture is subjected to a primary vulcanization treatment at a temperature of 170°C to 180°C for 10 min to 12 min, and then placed in a temperature environment of 150°C to 160°C for a secondary vulcanization treatment for 2 h to 3 h to obtain the rotary rubber core.

2. The preparation method of an oil-resistant rotary rubber core according to claim 1, characterized in that, The mixed rubber matrix is composed of nitrile rubber and hydrogenated nitrile rubber in a weight ratio of 1:

1.

3. The preparation method of an oil-resistant rotary rubber core according to claim 2, characterized in that, The acrylonitrile content of the nitrile rubber is 32% to 33%, and the acrylonitrile content in the hydrogenated nitrile rubber is 36% to 42%.

4. The preparation method of an oil-resistant rotary rubber core according to claim 1, characterized in that, The preparation method of the carbon black-modified polyacrylate raw rubber comprises the following steps: Carbon black and a nitric acid solution are mixed and dispersed in a weight ratio of 1 to 2:10 to 20, and then heated to 90°C to 100°C and reacted for 15 h to 20 h to obtain carboxyl-modified carbon black; The carboxyl-modified carbon black, a glycol derivative, dicyclohexylcarbodiimide, and 4-dimethylaminopyridine are mixed in a weight ratio of 1:2 to 3:3 to 4:0.5 to 0.8 and reacted in a temperature environment of 20°C to 25°C for 20 h to 24 h to obtain hydroxyl-modified carbon black; The hydroxyl-modified carbon black, an acrylic acid derivative, dicyclohexylcarbodiimide, and 4-dimethylaminopyridine are mixed in a weight ratio of 1:2 to 3:4 to 5:0.8 to 1 and reacted in a temperature environment of 20°C to 25°C for 20 h to 24 h to obtain acrylic acid derivative-modified carbon black; The acrylic acid derivative-modified carbon black, methyl acrylate, ethyl acrylate, a water-soluble emulsifier, and deionized water are mixed and stirred in a weight ratio of 1 to 2:10 to 15:10 to 15:0.1 to 0.5:68 to 78 to form a mixed emulsion. The mixed emulsion is mixed with a radical initiator and heated to 60°C to 70°C and reacted for 3 h to 5 h, and then a polymerization inhibitor is added and the reaction is controlled at 30°C to 40°C for 20 min to 30 min to obtain the carbon black-modified polyacrylate raw rubber.

5. The preparation method of an oil-resistant rotary rubber core according to claim 4, characterized in that, The mass concentration of the nitric acid solution is 50% to 60%.

6. The preparation method of an oil-resistant rotary rubber core according to claim 4, characterized in that, The glycol derivative includes ethylene glycol, 1,2-propanediol, or 1,3-propanediol.

7. The preparation method of an oil-resistant rotating rubber core according to claim 4, characterized in that, The acrylic acid derivative includes acrylic acid or methacrylic acid.

8. The preparation method of an oil-resistant rotary rubber core according to claim 4, characterized in that, The polymerization inhibitor includes N,N-diethylhydroxylamine or N-isopropylhydroxylamine.

9. The preparation method of an oil-resistant rotary rubber core according to claim 4, characterized in that, The weight ratio of the mixed emulsion: radical initiator: polymerization inhibitor is 1:0.01 to 0.05:0.01 to 0.

02.

10. A rotary rubber core prepared by the preparation method of a rotary rubber core with oil resistance according to any one of claims 1 to 9.

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