Oil-resistant and aging-resistant NBR compound and preparation method thereof

Abstract

The application discloses an oil-resistant and aging-resistant NBR mixing rubber and a preparation method thereof, and relates to the technical field of high polymer materials.The application comprises the following steps: respectively pretreating raw materials for preparing the NBR mixing rubber; performing one-stage mixing of raw rubber and part of auxiliary materials in a closed kneader and cooling; performing two-stage mixing of the one-stage mixing rubber after cooling and residual auxiliary materials and a vulcanization system in the closed kneader; stopping the two-stage mixing rubber and filtering the two-stage mixing rubber through a rubber filter; and placing the filtered rubber in a mold for high-temperature and pressurized vulcanization molding.The application adds a filling and reinforcing system such as carbon black in different temperature intervals in stages by adopting a step-by-step and temperature-controlled mixing process, and controls the upper limit of the temperature of each mixing stage and a rubber discharging point.The controlled dispersion process is helpful to forming a more stable structure in the rubber, and can improve the modulus, tensile strength and wear resistance of the rubber, so that the product performance is more stable.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, and in particular relates to an oil-resistant and aging-resistant NBR compound and its preparation method. Background Technology

[0002] In existing technologies, nitrile rubber (NBR) compounds are widely used to manufacture oil-resistant rubber products. However, their long-term oil resistance and resistance to thermo-oxidative aging remain significant challenges. Especially under dynamic operating conditions involving continuous contact with harsh media such as fuel oil and lubricating oil, accompanied by temperature fluctuations, NBR products prepared by traditional processes are prone to problems such as uneven dispersion of compounding agents, imperfect vulcanization network structure, or processing defects. This can lead to increased swelling rate, rapid decline in physical properties, and even premature failure, severely affecting sealing reliability and equipment lifespan. Therefore, we propose an oil-resistant and aging-resistant NBR compound and its preparation method. Summary of the Invention

[0003] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution: This invention relates to an oil-resistant and aging-resistant NBR compound and its preparation method, comprising the following steps: Step S1: Pre-treat the raw materials used to prepare NBR compound separately; Step S2: Mix the pretreated raw rubber with some auxiliary materials in an internal mixer and then cool it. Step S3: The cooled first-stage compound is mixed with the remaining auxiliary materials and vulcanization system in a Banbury mixer for a second stage of mixing; Step S4: Let the obtained two-stage compounded final rubber stand and filter it through a rubber filter machine; Step S5: Place the filtered rubber material into a mold for high-temperature and high-pressure vulcanization molding.

[0004] Further, in step S1, the raw materials, by weight, are: 100 parts of nitrile rubber raw rubber; 30-50 parts of carbon black filler system; 3-8 parts of activator nano zinc oxide; 2-5 parts of antioxidant system; 3-8 parts of solid processing aid; 10-20 parts of liquid plasticizer; 1-3 parts of coupling agent; 1-3 parts of vulcanizing agent system; 1-2.5 parts of accelerator; and 0.1-0.5 parts of scorching inhibitor.

[0005] Furthermore, step 1 includes the following steps: Step S11: Place the raw nitrile rubber on an open mixing mill. Under the process condition that the roller surface temperature is constant at 40-50℃, adjust the distance between the two rollers to 0.5-1.0 mm and repeatedly pass the raw rubber through the mill 3 to 5 times until the rubber material is evenly wrapped around the rollers and the surface is smooth, forming a rubber material layer of uniform thickness. Step S12: Place the carbon black filling system, the activator nano zinc oxide and the antioxidant system into a circulating hot air drying device and dry them continuously for 2-3 hours in the temperature range of 100-110℃. Then transfer them to a sealed, moisture-proof container for cooling and storage. The water content of the treated material does not exceed 0.5% by mass.

[0006] Furthermore, step S2 includes the following steps: Step S21: Start the internal mixer, set the initial temperature of the mixing chamber to 70-80℃, set the rotor speed to 40-60 rpm, and put in the nitrile rubber raw rubber that has been pretreated in step S1 for plasticizing and mixing for 2-3 minutes. Step S22: Through the feeding port on the internal mixer, add the first part of carbon black, which accounts for one-third of the total weight of the carbon black filling system, all the solid processing aids, the activator nano zinc oxide, the antioxidant system and the anti-scorching agent in sequence. Step S23: Through the shearing heat generated by the internal mixer itself and external heating, the temperature of the material in the mixing chamber rises evenly. When the temperature measuring system shows that the material temperature reaches the discharge temperature point of 120-130℃, the internal mixer opens the discharge door to discharge a section of mixed rubber, which is then placed in a room temperature environment to cool until it is consistent with the ambient temperature.

[0007] Furthermore, step S3 includes the following steps: Step S31: Put the first section of compounded rubber, which has been cooled to room temperature, back into the internal mixer, adjust the initial temperature of the mixing chamber to 60-70℃, and adjust the rotor speed to 30-50 rpm; Step S32: Add the second part of carbon black, which accounts for two-thirds of the remaining total weight of the carbon black filling system, all liquid plasticizer and coupling agent into the mixing chamber in sequence; Step S33: Continue the mixing process. When the material temperature in the mixing chamber rises to the range of 100-110℃, add the entire vulcanizing agent system and accelerator. Step S34: Maintain mixing for 2-3 minutes to ensure uniform dispersion of vulcanizing agent and accelerator. When the material temperature further rises to the final mixing and discharge temperature of 110-120℃, perform the discharge operation to obtain the final mixed rubber.

[0008] Furthermore, step S4 includes the following steps: Step S41: Place the final compound in a clean, cool, and ventilated area and let it stand at ambient temperature for 8-12 hours to eliminate the internal stress generated during the mixing process and allow the compounding agents to further diffuse evenly. Step S42: Feed the placed rubber compound into a screw filter press. Control the barrel temperature at 80-100℃ so that the rubber compound passes through a multi-layer filter device with a pore size of 150-200 mesh to filter out the small solid impurities, undispersed compounding agent agglomerates and gel particles.

[0009] Furthermore, step S5 includes the following steps: Step S51: Prepare a metal mold according to the required shape and specifications of the finished product, and clean and preheat the mold cavity; Step S52: After accurately weighing the filtered rubber material, fill it into the preheated mold cavity, close the mold, and place it between the hot plates of the flat vulcanizing machine. Step S53: Start the flat vulcanizing machine, apply a mold closing pressure of 10-15 MPa to the mold, and keep the hot plate temperature constant between 160-170℃. According to the size of the thickest part of the finished product, set the vulcanization time at 1.2-1.5 minutes / mm to carry out constant temperature and pressure vulcanization reaction. Step S54: After the preset vulcanization time is reached, release the pressure, open the mold, and take out the vulcanized product to obtain the oil-resistant and aging-resistant NBR compound.

[0010] Furthermore, the acrylonitrile content of the raw nitrile rubber is in the range of 34% to 38%; The carbon black filling system is composed of high abrasion-resistant carbon black and semi-reinforcing carbon black, and the mass ratio of high abrasion-resistant carbon black to semi-reinforcing carbon black is in the range of 2:1 to 3:1. The antioxidant system is composed of a polymeric antioxidant 2,2,4-trimethyl-1,2-dihydroquinoline polymer and a p-phenylenediamine antioxidant N-isopropyl-N'-phenyl-p-phenylenediamine, with a mass ratio of 1:1 to 1:1.5.

[0011] The present invention has the following beneficial effects: 1. This invention employs a step-by-step, temperature-controlled mixing process, adding carbon black and other reinforcing fillers in stages and at different temperature ranges, and precisely controlling the upper temperature limit and discharge point of each mixing stage. This effectively optimizes the dispersibility of fillers in the rubber matrix. This controlled dispersion process helps to form a more uniform and stable network structure in the rubber compound, thereby laying a good foundation for the physical properties of the finished compound and improving its key mechanical indicators such as tensile stress, tensile strength, and abrasion resistance, making the product performance more stable.

[0012] 2. This invention effectively reduces the risk of scorching caused by premature high temperature by adding vulcanizing agents and accelerators at a relatively low temperature in the later stage of a specific mixing process and completing the final mixing and debinding within a controlled time. This intervention in the vulcanization process ensures processing safety and facilitates sufficient cross-linking reaction in subsequent vulcanization stages, thereby improving the uniformity of cross-linking density of the finished vulcanizate and enabling it to obtain better compression set performance and elastic recovery rate.

[0013] 3. This invention removes minute impurities, undispersed compounding agent aggregates, and gels formed during the mixing process. This process improves the homogeneity and purity of the rubber compound, directly reducing potential defects in the finished product. For applications requiring high cleanliness and high reliability, this effect can effectively improve the yield and long-term usability of the product.

[0014] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the process for preparing an oil-resistant and aging-resistant NBR compound and its preparation method according to the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Please see Figure 1 As shown, this invention relates to an oil-resistant and aging-resistant NBR compound and its preparation method, comprising the following steps: Step S1: Pre-treat the raw materials used to prepare NBR compound separately; Step S2: Mix the pretreated raw rubber with some auxiliary materials in an internal mixer and then cool it. Step S3: The cooled first-stage compound is mixed with the remaining auxiliary materials and vulcanization system in a Banbury mixer for a second stage of mixing; Step S4: Let the obtained two-stage compounded final rubber stand and filter it through a rubber filter machine; Step S5: Place the filtered rubber material into a mold for high-temperature and high-pressure vulcanization molding.

[0019] In step S1, the raw materials, by weight, are: 100 parts of nitrile rubber raw rubber; 30-50 parts of carbon black filler system; 3-8 parts of activator nano zinc oxide; 2-5 parts of antioxidant system; 3-8 parts of solid processing aid; 10-20 parts of liquid plasticizer; 1-3 parts of coupling agent; 1-3 parts of vulcanizing agent system; 1-2.5 parts of accelerator; and 0.1-0.5 parts of scorching inhibitor.

[0020] Step 1 includes the following steps: Step S11: Place the raw nitrile rubber on an open mixing mill. Under the process condition that the roller surface temperature is constant at 40-50℃, adjust the distance between the two rollers to 0.5-1.0 mm and repeatedly pass the raw rubber through the mill 3 to 5 times until the rubber material wraps around the rollers evenly, the surface is smooth, and a rubber material layer of uniform thickness is formed. Step S12: Place the carbon black filling system, the activator nano zinc oxide and the antioxidant system into a circulating hot air drying device and dry them continuously for 2-3 hours in the temperature range of 100-110℃. Then transfer them to a sealed, moisture-proof container for cooling and storage. The water content of the treated material does not exceed 0.5% by mass.

[0021] Step S2 includes the following steps: Step S21: Start the internal mixer, set the initial temperature of the mixing chamber to 70-80℃, set the rotor speed to 40-60 rpm, and put in the nitrile rubber raw rubber that has been pretreated in step S1 for plasticizing and mixing for 2-3 minutes. Step S22: Through the feeding port on the internal mixer, add the first part of carbon black, which accounts for one-third of the total weight of the carbon black filling system, all the solid processing aids, the activator nano zinc oxide, the antioxidant system and the anti-scorching agent in sequence. Step S23: Through the shearing heat generated by the internal mixer itself and external heating, the temperature of the material in the mixing chamber rises evenly. When the temperature measuring system shows that the material temperature reaches the discharge temperature point of 120-130℃, the internal mixer opens the discharge door to discharge a section of mixed rubber, which is then placed in a room temperature environment to cool until it is consistent with the ambient temperature.

[0022] Step S3 includes the following steps: Step S31: Put the section of compounded rubber cooled to room temperature back into the internal mixer, adjust the initial temperature of the mixing chamber to 60-70℃, and adjust the rotor speed to 30-50 rpm; Step S32: Add the second part of carbon black, which accounts for two-thirds of the remaining total weight of the carbon black filling system, all liquid plasticizer and coupling agent into the mixing chamber in sequence; Step S33: Continue the mixing process. When the material temperature in the mixing chamber rises to the range of 100-110℃, add the entire vulcanizing agent system and accelerator. Step S34: Maintain mixing for 2-3 minutes to ensure uniform dispersion of vulcanizing agent and accelerator. When the material temperature further rises to the final mixing and discharge temperature of 110-120℃, perform the discharge operation to obtain the final mixed rubber.

[0023] Step S4 includes the following steps: Step S41: Place the final compound in a clean, cool, and well-ventilated area and let it stand at ambient temperature for 8-12 hours to eliminate the internal stress generated during the mixing process and allow the compounding agents to further diffuse evenly. Step S42: Feed the placed rubber compound into a screw filter press. Control the barrel temperature at 80-100℃ so that the rubber compound passes through a multi-layer filter device with a pore size of 150-200 mesh to filter out the small solid impurities, undispersed compounding agent agglomerates and gel particles.

[0024] Step S5 includes the following steps: Step S51: Prepare a metal mold according to the required shape and specifications of the finished product, and clean and preheat the mold cavity; Step S52: After accurately weighing the filtered rubber material, fill it into the preheated mold cavity, close the mold, and place it between the hot plates of the flat vulcanizing machine. Step S53: Start the flat vulcanizing machine, apply a mold closing pressure of 10-15 MPa to the mold, and keep the hot plate temperature constant between 160-170℃. According to the size of the thickest part of the finished product, set the vulcanization time at 1.2-1.5 minutes / mm to carry out constant temperature and pressure vulcanization reaction. Step S54: After the preset vulcanization time is reached, release the pressure, open the mold, and take out the vulcanized product to obtain an oil-resistant and aging-resistant NBR compound.

[0025] The acrylonitrile content of nitrile rubber raw rubber is in the range of 34% to 38%; The carbon black filler system consists of high abrasion-resistant carbon black and semi-reinforcing carbon black, with a mass ratio of high abrasion-resistant carbon black to semi-reinforcing carbon black ranging from 2:1 to 3:1. The antioxidant system is composed of a polymeric antioxidant 2,2,4-trimethyl-1,2-dihydroquinoline polymer and a p-phenylenediamine antioxidant N-isopropyl-N'-phenyl-p-phenylenediamine, with a mass ratio of 1:1 to 1:1.5.

[0026] One specific application of this embodiment is: Implementation materials Nitrile rubber raw material (acrylonitrile content 36%): 100 parts; Carbon black filler system (high abrasion-resistant carbon black: semi-reinforcing carbon black = 2.5:1): 40 parts; Nano zinc oxide activator: 5 parts; Antioxidant system (polymeric antioxidant 2,2,4-trimethyl-1,2-dihydroquinoline polymer: N-isopropyl-N'-phenyl-p-phenylenediamine = 1:1.2): 3.5 parts; Solid processing aids: 5 parts; Liquid plasticizer: 15 parts; Coupling agent: 2 parts; Vulcanizing agent system: 2 parts; Accelerator: 1.8 parts; Scorch inhibitor: 0.3 parts; Implementation steps Step S1: Raw material pretreatment Step S11, Pretreatment of raw nitrile rubber: Place the raw nitrile rubber on an open mixing mill, set the roller surface temperature to a constant 45°C, adjust the distance between the two rollers to 0.8 mm, and repeatedly pass the raw rubber through the mill 4 times until the rubber compound is evenly wrapped around the rollers, the surface is smooth, and a rubber compound layer of uniform thickness is formed.

[0027] Step S12, Drying of solid raw materials: The carbon black filling system, the activator nano zinc oxide and the antioxidant system are placed in a circulating hot air drying device and dried continuously at 105°C for 2.5 hours. Then, they are transferred to a sealed, moisture-proof container for cooling and storage. After testing, the water content of the material is 0.3%, which meets the requirement of not exceeding 0.5%.

[0028] Step S2, Part 1 Mixing Step S21: Start the internal mixer, set the initial temperature of the mixing chamber to 75℃, set the rotor speed to 50 rpm, and put in the pretreated nitrile rubber raw rubber for plasticizing and mixing for 2.5 minutes.

[0029] Step S22: Through the feeding port on the internal mixer, add the first part of carbon black (accounting for one-third of the total weight of the carbon black filling system, approximately 13.3 parts), all solid processing aids, activator nano zinc oxide, antioxidant system, and anti-scorching agent in sequence.

[0030] Step S23: Relying on the shear heat generated by the internal mixer itself and external heating, the material temperature in the mixing chamber rises evenly. When the temperature measuring system shows that the material temperature reaches 125°C, the internal mixer opens the discharge door, discharges a section of mixed rubber, and places it in a room temperature environment to cool it down to the same temperature as the environment.

[0031] Step S3, Second-stage mixing Step S31: Put the section of compounded rubber cooled to room temperature back into the internal mixer, adjust the initial temperature of the mixing chamber to 65°C, and adjust the rotor speed to 40 rpm.

[0032] Step S32: Add the second part of carbon black (accounting for two-thirds of the total weight of the carbon black filling system, approximately 26.7 parts), all liquid plasticizer, and coupling agent sequentially into the mixing chamber.

[0033] Step S33: Continue the mixing process. When the material temperature in the mixing chamber rises to 105°C, add the entire vulcanizing agent system and accelerator.

[0034] Step S34: Maintain mixing for 2.5 minutes to ensure uniform dispersion of vulcanizing agent and accelerator. When the material temperature further rises to 115°C, perform the debinding operation to obtain the final compound.

[0035] Step S4, Parking and Filtration Step S41: Place the final compound in a clean, cool, and well-ventilated area and let it stand at ambient temperature for 10 hours to eliminate the internal stress generated during the mixing process and allow the compounding agents to diffuse more evenly.

[0036] Step S42: Feed the placed rubber material into the screw filter press, control the barrel temperature to 90°C, and let the rubber material pass through the multi-layer filter screen with a pore size of 180 mesh to filter out small solid impurities, undispersed compounding agent agglomerates and gel particles.

[0037] Step S5: High-temperature and high-pressure vulcanization molding Step S51: Prepare a metal mold according to the required shape and specifications of the finished product (a sealing gasket with a thickness of 5 mm), clean the mold cavity and preheat it.

[0038] Step S52: After accurately weighing the filtered rubber material, fill it into the preheated mold cavity, close the mold, and place it between the hot plates of the flat vulcanizing machine.

[0039] Step S53: Start the flat vulcanizing machine, apply a mold closing pressure of 12 MPa to the mold, and keep the hot plate temperature constant at 165℃. Set the vulcanization time according to the standard of 1.3 minutes / mm (5×1.3=6.5 minutes) to carry out the constant temperature and pressure vulcanization reaction.

[0040] Step S54: After the preset vulcanization time is reached, release the pressure, open the mold, and take out the vulcanized product to obtain an oil-resistant and aging-resistant NBR compound.

[0041] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0042] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. An oil-resistant and aging-resistant NBR compound and its preparation method, characterized in that: Includes the following steps: Step S1: Pre-treat the raw materials used to prepare NBR compound separately; Step S2: Mix the pretreated raw rubber with some auxiliary materials in an internal mixer and then cool it. Step S3: The cooled first-stage compound is mixed with the remaining auxiliary materials and vulcanization system in a Banbury mixer for a second stage of mixing; Step S4: Let the obtained two-stage compounded final rubber stand and filter it through a rubber filter machine; Step S5: Place the filtered rubber material into a mold for high-temperature and high-pressure vulcanization molding.

2. The oil-resistant and aging-resistant NBR compound and its preparation method according to claim 1, characterized in that, In step S1, the raw materials, by weight, are: 100 parts of nitrile rubber raw rubber; 30-50 parts of carbon black filler system; 3-8 parts of activator nano zinc oxide; 2-5 parts of antioxidant system; 3-8 parts of solid processing aid; and 10-20 parts of liquid plasticizer. 1-3 parts coupling agent; 1-3 parts vulcanizing agent system; 1-2.5 parts accelerator; 0.1-0.5 parts anti-scorching agent.

3. The oil-resistant and aging-resistant NBR compound and its preparation method according to claim 1, characterized in that, Step 1 includes the following steps: Step S11: Place the raw nitrile rubber on an open mixing mill. Under the process condition that the surface temperature of the rollers is constant at 40-50℃, adjust the distance between the two rollers to 0.5-1.0 mm and repeatedly pass the raw rubber through the mill 3 to 5 times. Step S12: Place the carbon black filling system, the activator nano zinc oxide and the antioxidant system into a circulating hot air drying device and dry them continuously for 2-3 hours in the temperature range of 100-110℃. Then transfer them to a sealed, moisture-proof container for cooling and storage.

4. The oil-resistant and aging-resistant NBR compound and its preparation method according to claim 1, characterized in that, Step S2 includes the following steps: Step S21: Start the internal mixer, set the initial temperature of the mixing chamber to 70-80℃, set the rotor speed to 40-60 rpm, and put in the nitrile rubber raw rubber that has been pretreated in step S1 for plasticizing and mixing for 2-3 minutes. Step S22: Through the feeding port on the internal mixer, add the first part of carbon black, which accounts for one-third of the total weight of the carbon black filling system, all the solid processing aids, the activator nano zinc oxide, the antioxidant system and the anti-scorching agent in sequence. Step S23: Through the shearing heat generated by the internal mixer itself and external heating, the temperature of the material in the mixing chamber rises evenly. When the temperature measuring system shows that the material temperature reaches the discharge temperature point of 120-130℃, the internal mixer opens the discharge door to discharge a section of mixed rubber, which is then placed in a room temperature environment to cool until it is consistent with the ambient temperature.

5. The oil-resistant and aging-resistant NBR compound and its preparation method according to claim 1, characterized in that, Step S3 includes the following steps: Step S31: Put the first section of compounded rubber, which has been cooled to room temperature, back into the internal mixer, adjust the initial temperature of the mixing chamber to 60-70℃, and adjust the rotor speed to 30-50 rpm; Step S32: Add the second part of carbon black, which accounts for two-thirds of the remaining total weight of the carbon black filling system, all liquid plasticizer and coupling agent into the mixing chamber in sequence; Step S33: Continue the mixing process. When the material temperature in the mixing chamber rises to the range of 100-110℃, add the entire vulcanizing agent system and accelerator. Step S34: Maintain mixing for 2-3 minutes. When the material temperature rises further to the final mixing and debinding temperature of 110-120℃, perform the debinding operation to obtain the final mixed rubber.

6. The oil-resistant and aging-resistant NBR compound and its preparation method according to claim 1, characterized in that, Step S4 includes the following steps: Step S41: Place the final compound in a clean, cool, and ventilated area and let it stand at ambient temperature for 8-12 hours to eliminate the internal stress generated during the mixing process and allow the compounding agents to further diffuse evenly. Step S42: Feed the placed rubber compound into a screw filter press. Control the barrel temperature at 80-100℃ so that the rubber compound passes through a multi-layer filter device with a pore size of 150-200 mesh to filter out the small solid impurities, undispersed compounding agent agglomerates and gel particles.

7. The oil-resistant and aging-resistant NBR compound and its preparation method according to claim 1, characterized in that, Step S5 includes the following steps: Step S51: Prepare a metal mold according to the required shape and specifications of the finished product, and clean and preheat the mold cavity; Step S52: After accurately weighing the filtered rubber material, fill it into the preheated mold cavity, close the mold, and place it between the hot plates of the flat vulcanizing machine. Step S53: Start the flat vulcanizing machine, apply a mold closing pressure of 10-15 MPa to the mold, and keep the hot plate temperature constant between 160-170℃. According to the size of the thickest part of the finished product, set the vulcanization time at 1.2-1.5 minutes / mm to carry out constant temperature and pressure vulcanization reaction. Step S54: After the preset vulcanization time is reached, release the pressure, open the mold, and take out the vulcanized product to obtain the oil-resistant and aging-resistant NBR compound.

8. The oil-resistant and aging-resistant NBR compound and its preparation method according to claim 2, characterized in that, The acrylonitrile content of the raw nitrile rubber is in the range of 34% to 38%; The carbon black filling system is composed of high abrasion-resistant carbon black and semi-reinforcing carbon black, and the mass ratio of high abrasion-resistant carbon black to semi-reinforcing carbon black is in the range of 2:1 to 3:

1. The antioxidant system is composed of a polymeric antioxidant 2,2,4-trimethyl-1,2-dihydroquinoline polymer and a p-phenylenediamine antioxidant N-isopropyl-N'-phenyl-p-phenylenediamine, with a mass ratio of 1:1 to 1:1.5.

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