High-temperature-resistant and oil-resistant cable special for electrical equipment

Abstract

The invention relates to the technical field of rubber materials and wire and cable manufacturing, and discloses a high-temperature-resistant and oil-resistant cable special for electrical equipment, and the cable material is prepared from hydrogenated nitrile rubber, ethylene-vinyl acetate rubber, zinc dimethacrylate, alpha-methylstyrene dimer, prefabricated drying functional powder and a compounding agent. The prefabricated dried functional powder is prepared from fumed silica adsorbed epoxidized soybean oil and calcium stearate through a special process. The preparation method comprises a two-step method of high-temperature mixing induced in-situ polymerization and low-temperature mixing and vulcanizing. According to the invention, the heat resistance of a matrix is improved by constructing a zinc dimethacrylate ion enhanced network, and the plasticizer is locked by utilizing dual mechanisms of physical adsorption and chemical anchoring of the functional powder, so that the problem of hardening shrinkage of the material caused by migration of the plasticizer in a high-temperature oil environment is effectively solved; and the long-term mechanical stability and processability of the cable material are improved.

Description

Technical Field

[0001] This invention relates to the field of rubber materials and wire and cable manufacturing technology, specifically to a high-temperature and oil-resistant electrical equipment cable. Background Technology

[0002] In fields such as oil drilling platforms, high-power locomotive engines, and heavy industrial machinery, electrical connection systems operate under extremely harsh conditions for extended periods. The cables used in these systems not only withstand continuous high temperatures but also frequently come into contact with various fuel oils, hydraulic oils, or lubricants. If the cable sheath and insulation fail in this high-temperature, oily, and volatile environment, it can lead to anything from a decrease in insulation resistance causing equipment shutdowns to short circuits or even fires.

[0003] Currently, the selection of base materials for rubber cable materials is mainly based on specific priorities. While ordinary nitrile rubber (NBR) has decent oil resistance, it cannot withstand prolonged high temperatures above 120°C, and the carbon chains are prone to thermal-oxidative aging leading to cracking. To improve heat resistance, the industry has begun to shift towards using ethylene-vinyl acetate rubber (EVM) or hydrogenated nitrile rubber (HNBR). To reduce the Mooney viscosity of these high-performance rubbers, improve extrusion processing performance, and impart the necessary flexibility to the cable, existing technologies typically add large amounts of liquid plasticizers, such as phthalates or polyester oils, to the formulation. Simultaneously, to meet strength requirements, reinforcing fillers such as carbon black or silica are directly added during the mixing process.

[0004] However, this traditional modification technique has drawbacks. One issue is the persistence of the plasticizer. The liquid small-molecule plasticizer interacts only with the rubber macromolecules through physical van der Waals forces. Under high-temperature oil immersion conditions, the plasticizer easily migrates to the material surface and is extracted by the external medium. This migration causes the cable sheath to shrink, generating internal stress, drastically increasing material hardness and losing flexibility, ultimately leading to brittle fracture during equipment vibration. Secondly, there are limitations in the processing technology. Directly adding liquid oil to the internal mixer can easily cause the rubber compound to slip on the metal wall, making it difficult to effectively transmit rotor shear force and resulting in uneven filler dispersion. This not only reduces production efficiency but also causes severe batch-to-batch fluctuations in the electrical insulation performance of the finished cable. Therefore, this invention provides a high-temperature and oil-resistant cable specifically for electrical equipment to address the shortcomings of the existing technology. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a high-temperature and oil-resistant cable for electrical equipment. This solves the problems of existing rubber cable materials for electrical equipment, which suffer from increased material hardness, volume shrinkage, and significant degradation of mechanical properties due to plasticizer migration in high-temperature and oily environments, and also make it difficult to balance processing fluidity and aging resistance.

[0006] To achieve the above objectives, the present invention provides the following technical solution: The first aspect of this invention provides a high-temperature and oil-resistant cable for electrical equipment, comprising a cable core and a sheath covering the outside of the cable core. The sheath is made of raw materials comprising the following parts by weight: 40-60 parts hydrogenated nitrile rubber; 40-60 parts ethylene-vinyl acetate rubber; 18-25 parts zinc dimethacrylate; 0.6-1.5 parts α-methylstyrene dimer; 12-18 parts pre-dried functional powder; 0.4-0.6 parts anti-scorching agent; 4-6 parts activated magnesium oxide; 2-2.5 parts antioxidant; 3.0-4.0 parts dicumyl peroxide; 0.8-1.5 parts triallyl isocyanurate; and 3-5 parts calcium oxide masterbatch.

[0007] By adopting the above technical solution, and using hydrogenated nitrile rubber and ethylene-vinyl acetate rubber as the matrix, combined with the synergistic effect of the ion crosslinking network constructed by in-situ polymerization of zinc dimethacrylate and the pre-dried functional powder, the effect of high temperature resistance, oil swelling resistance and long-term mechanical property stability is obtained.

[0008] The specific mechanism of action is as follows: During high-temperature mixing, zinc dimethacrylate undergoes a grafting reaction with the matrix rubber and homopolymerizes to form nanoscale polyzinc dimethacrylate ion clusters. These ion clusters act as rigid physical crosslinking points, enhancing the material's modulus and heat resistance. α-Methylstyrene dimer acts as a chain transfer agent, regulating the polymerization chain length of zinc dimethacrylate to prevent the formation of coarse aggregates and ensure uniform dispersion.

[0009] Pre-formed dried functional powder addresses plasticizer migration through a dual mechanism of physical anchoring and chemical grafting. This powder contains fumed silica adsorbed with epoxidized soybean oil and dispersed calcium stearate. The process involves the following steps: Physical adsorption stage: During the mixing and room temperature storage stages, liquid epoxidized soybean oil is physically adsorbed into the nanopores and aggregate structure of fumed silica, which restricts the free Brownian motion of liquid molecules and reduces their diffusion and volatilization to the material surface.

[0010] Reaction triggering stage: When the cable material is in a high-temperature oil medium or a long-term thermal aging environment, the trace acidic substances produced by the penetration of external acidic medium or the thermal-oxidative degradation of the rubber matrix preferentially react with the calcium stearate dispersed in the powder, displacing free calcium ions.

[0011] Chemical anchoring stage: Free calcium ions act as Lewis acid catalysts, activating the epoxy groups on the epoxidized soybean oil molecular chains. The activated epoxy groups undergo ring-opening addition or transesterification reactions with carboxyl groups, hydroxyl groups, or polar groups on the side chains of the rubber matrix produced by oxidation, chemically bonding the originally free small-molecule plasticizer to the polymer network. This in-situ transformation chemical bonding mechanism not only permanently locks in the plasticizer, preventing its extraction by the medium and subsequent material shrinkage and hardening, but also forms a secondary cross-linked network that repairs the main chain network broken due to aging, maintaining the material's mechanical strength.

[0012] Preferably, the raw materials of the sheath layer include: 50-55 parts by weight of hydrogenated nitrile rubber; 45-50 parts by weight of ethylene-vinyl acetate rubber; 20-22 parts by weight of zinc dimethacrylate; 0.8-1.2 parts by weight of α-methylstyrene dimer; and 15 parts by weight of pre-dried functional powder.

[0013] By adopting the above technical solution, the rubber-plastic blend ratio and the amount of reinforcing agent were optimized, so that the matrix compatibility and processing viscosity were balanced, ensuring that the extruded surface was smooth and dense.

[0014] Preferably, the pre-dried functional powder is made of fumed silica, epoxidized soybean oil and calcium stearate, wherein the weight ratio of fumed silica, epoxidized soybean oil and calcium stearate is 10:20-28:0.3-0.6.

[0015] By adopting the above technical solution, the oil loading is controlled within the oil absorption value threshold of fumed silica, ensuring that the powder is in a dry and flowing state and preventing agglomeration; at the same time, the proportion of calcium stearate is limited to ensure catalytic efficiency and avoid excessive metal ion residue affecting electrical insulation.

[0016] Preferably, the pre-prepared dried functional powder is prepared by the following steps: calcium stearate is dispersed in epoxidized soybean oil heated to 55-60°C to form a modified oil solution, and then the modified oil solution is atomized and sprayed into fumed silica under high-speed stirring. The material temperature is maintained at 55-65°C by shear friction heat, and the mixture is mixed until the material is in a dry powder state.

[0017] By adopting the above technical solution, hot oil is used to reduce viscosity and improve the dispersion of calcium stearate. Combined with the atomization spraying process, the modified oil is uniformly penetrated into the interior of silica agglomerates in the form of microdroplets, rather than simply coating the surface, thus improving the stability of physical oil locking.

[0018] Preferably, the scorching inhibitor is 2,6-di-tert-butyl-4-methylphenol; and the antioxidant is 4,4'-bis(α,α-dimethylbenzyl)diphenylamine.

[0019] By adopting the above technical solutions, the anti-scorching agent BHT provides processing safety in the high-temperature mixing section and prevents early cross-linking of the rubber compound; the antioxidant, as a high-temperature resistant amine antioxidant, works synergistically with the above-mentioned chemical anchoring mechanism to further capture free radicals and delay the thermo-oxidative aging chain reaction.

[0020] The second aspect of this invention provides a method for preparing a high-temperature and oil-resistant electrical equipment cable, comprising the following steps: S1. Prefabrication of cable core: Select a conductor and extrude an insulation layer on its outer layer to make an insulated wire core. Twist and fill the insulated wire core into a cable to make a cable core. S2. Hydrogenated nitrile rubber, ethylene-vinyl acetate rubber, antioxidant, active magnesium oxide and scorch inhibitor are mixed in an internal mixer. Then zinc dimethacrylate, α-methylstyrene dimer and pre-dried functional powder are added. The mixture is heated and mixed at a constant temperature of 136-145℃ to obtain the A-section compound. S3. Cool the A-section compound to below 75°C, add dicumyl peroxide, triallyl isocyanurate and calcium oxide masterbatch, mix evenly and then sheet to obtain the sheath-specific compound. S4. The special compound rubber for sheathing obtained in step S3 is extruded onto the outer layer of the cable core prefabricated in step S1, and then subjected to high-temperature vulcanization crosslinking to obtain the finished product.

[0021] The preparation method employs a segmented temperature control process to ensure that each component functions within a specific temperature window.

[0022] During the S2 high-temperature mixing stage, the temperature is set at 136-145℃ to ensure complete melting and molecular-level dispersion of zinc dimethacrylate, followed by in-situ polymerization under mechanical shear to form an ion-reinforcing network. Simultaneously, this temperature promotes the bonding between the oil phase in the pre-formed powder and the hydroxyl groups on the silica surface, enhancing the interfacial interaction between the filler and the matrix.

[0023] During the S3 low-temperature mixing stage, the temperature is strictly controlled within the range of 65-75℃ to prevent the peroxide initiator from decomposing prematurely and causing scorching. Calcium oxide masterbatch is added at this stage to effectively absorb residual moisture in the system, ensuring the density of the subsequently vulcanized products.

[0024] In the S4 extrusion and cross-linking stage, the sheath material is directly extruded onto the prefabricated cable core and immediately subjected to high-temperature continuous vulcanization, ensuring a tight bond between the sheath and the cable core structure and forming a complete cable protection system.

[0025] Preferably, in step S2, the pre-dried functional powder is pretreated using the following method: epoxidized soybean oil is heated to 55-60°C in a mixing container, calcium stearate is added and stirred and dispersed for 15 minutes to obtain a mixture; fumed silica is added to a high-speed mixer, and the resulting mixture is sprayed through a high-pressure atomizing nozzle at a speed of 1500-1800 rpm; the spraying time is controlled to be 5-8 minutes, and the temperature is maintained at 55-65°C using shear heat; after the spraying is completed, mixing continues for 3-5 minutes until the material is discharged.

[0026] Pretreatment converts liquid plasticizers into solid powders, solving the problems of slippage and uneven dispersion caused by directly adding liquid oil in the internal mixer, and greatly improving mixing efficiency and the uniformity of the rubber compound.

[0027] Preferably, the process parameters for step S2 are controlled as follows: after adding zinc dimethacrylate, α-methylstyrene dimer and pre-dried functional powder, the pressure of the top plug of the internal mixer is increased to 0.6-0.8 MPa, and the rotor speed is increased to 75-95 rpm. The temperature of the rubber compound is raised to 136-145℃ within 2 minutes, and the constant temperature mixing time is 3-5 minutes.

[0028] High top bolt pressure and high rotation speed provide strong shear force, promoting rapid fusion of high-viscosity rubber matrix; rapid heating strategy shortens the thermal history of rubber compound, ensuring complete reaction of additives while reducing thermal breakage of rubber main chain.

[0029] Preferably, step S3 further includes: transferring the A-section compound to a two-roll mill, adjusting the roller gap to 1.5 mm for thin-pass heat dissipation; when the temperature of the compound drops to 65-75℃, adding dicumyl peroxide, triallyl isocyanurate and calcium oxide masterbatch; then performing triangular wrapping and left and right cutting operations 5-6 times each, adjusting the roller gap to 4 mm for sheeting, and curing at room temperature for 8-24 hours.

[0030] Thin-pass operation can quickly reduce rubber temperature; the cutting knife and triangular wrapping process force the rubber compound to undergo multi-dimensional tumbling and mixing, eliminating local aggregation of vulcanizing agents; the curing process relaxes internal stress and improves the dimensional stability of the rubber compound.

[0031] Preferably, in step S4, the crosslinking temperature is controlled at 178-185℃ and the steam pressure is controlled at 1.3-1.5MPa.

[0032] High-temperature and high-pressure steam conditions provide sufficient cross-linking activation energy, and external pressure is used to suppress the formation of micropores inside the product, thus ensuring the electrical strength of the insulation layer.

[0033] This invention provides a high-temperature and oil-resistant cable specifically for electrical equipment. It offers the following advantages: 1. This invention uses hydrogenated nitrile butadiene rubber and ethylene-vinyl acetate rubber as the matrix, combined with in-situ polymerization technology of zinc dimethacrylate, to improve the high-temperature resistance and oil resistance mechanical properties of the cable material. During the high-temperature mixing stage, zinc dimethacrylate generates nano-ionic clusters in situ under the regulation of α-methylstyrene dimers, constructing a high-strength ionic cross-linking network. This network structure enhances the modulus of the material and effectively resists the swelling effect of high-temperature oil media on the rubber molecular chains.

[0034] 2. This invention solves the problem of easy migration and precipitation of traditional liquid plasticizers in high-temperature oil environments by introducing pre-formed dried functional powder. This powder utilizes the porous structure of fumed silica to physically adsorb epoxidized soybean oil, and under the catalysis of calcium stearate, promotes a chemical grafting reaction between the plasticizer and the rubber matrix during thermo-oxidative aging. This mechanism, combining physical adsorption and chemical bonding, inhibits plasticizer extraction, prevents volume shrinkage and hardening brittleness in the cable insulation layer due to plasticizer loss, and ensures the long-term flexibility of the material.

[0035] 3. The preparation process of this invention improves the processing dispersibility and product density of high-filler systems. The pretreatment process converts liquid epoxidized soybean oil into a dry powder, avoiding the slippage phenomenon caused by directly adding liquid oil during mixing and improving shear mixing efficiency. Combined with a segmented temperature control process, it ensures molecular-level dispersion and controllable polymerization of zinc dimethacrylate in the rubber matrix, eliminating stress concentration points caused by localized agglomeration, thereby obtaining a cable material with a smooth surface and stable electrical insulation properties. Attached Figure Description

[0036] Figure 1 The following is a comparison of the performance changes of different components of the present invention under simulated acidic oil conditions; wherein, Figure (a) is a graph showing the retention rate of mechanical properties after aging of simulated acidic oil, and Figure (b) is a graph showing the change rate of 100% constant elongation stress after aging. Figure 2 Figure 1 shows a comparison of the basic mechanical properties and heat aging resistance of different components of the present invention; wherein, Figure 2(a) is a comparison of tensile strength values ​​before and after heat aging, and Figure 3(b) is a graph showing the rate of decay of heat aging performance. Figure 3 The figures show a comparison of the stability tests of different groups of the present invention after immersion in IRM 903 oil; wherein, Figure (a) is a graph of mass and volume stability after oil immersion, and Figure (b) is a graph of hardness increase after oil immersion. Detailed Implementation

[0037] The technical solutions in 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.

[0038] The main raw materials and reagents used in the following examples and comparative examples have the following sources and specifications. Reagents not specifically mentioned are all commercially available analytical grade or higher grade products.

[0039] Hydrogenated nitrile butadiene rubber (HNBR), chemically known as hydrogenated (acrylonitrile-butadiene) copolymer, CAS number 88254-10-8. It contains 36wt%-44wt% bound acrylonitrile (ACN), has a Mooney viscosity (ML(1+4)) of 70-90 at 100℃, and an iodine value less than 20mg / 100mg.

[0040] Ethylene-vinyl acetate rubber (EVM), chemically known as ethylene-vinyl acetate copolymer, CAS number 24937-78-8. It contains 60wt%-70wt% vinyl acetate (VA) and has a Mooney viscosity (ML(1+4)) of 20-35 at 100℃. It is a non-crystalline elastomer with high VA content.

[0041] Zinc dimethacrylate (ZDMA), CAS number 13189-00-9.

[0042] α-Methylstyrene dimer (AMSD), chemically named 2,4-diphenyl-4-methyl-1-pentene, CAS number 6362-80-7.

[0043] Fumed silica, CAS number 7631-86-9, has a specific surface area of ​​150-250 m². 2 / g.

[0044] Epoxidized soybean oil (ESO), CAS number 8013-07-8.

[0045] Calcium stearate, CAS number 1592-23-0.

[0046] Dicumyl peroxide (DCP), CAS number 80-43-3.

[0047] Triallyl isocyanurate (TAIC), CAS number 1025-15-6.

[0048] 2,6-Di-tert-butyl-4-methylphenol (BHT), CAS number 128-37-0.

[0049] 4,4'-Bis(α,α-dimethylbenzyl)diphenylamine (antioxidant), CAS number 10081-67-1.

[0050] Calcium oxide masterbatch, the active ingredient calcium oxide CAS number is 1305-78-8, and the calcium oxide content is 80wt%.

[0051] Active magnesium oxide, CAS number 1309-48-4.

[0052] Preparation Example 1: This preparation example provides a method for preparing pre-dried functional powder A1, including the following steps: (1) In a stirring container with a heating jacket, add 2500g of epoxidized soybean oil, heat to 55°C, then add 50g of calcium stearate, stir for 15 minutes until the calcium stearate is evenly dispersed in the oil phase to form a modified oil solution. (2) Put 1000g of fumed silica into the main chamber of the high-speed mixer, start the agitator, and set the speed to 1500rpm; (3) The modified oil prepared in step (1) is sprayed into the high-speed mixer chamber through a high-pressure atomizing nozzle. The spraying rate is controlled so that the oil is sprayed out within 6 minutes. The material temperature is maintained at 60°C by using shear friction heat. (4) After the oil is sprayed, continue mixing at 1500 rpm for 4 minutes until the material is loose, free of lumps and has free flow dry powder state. Discharge and seal the package to obtain pre-dried functional powder A1.

[0053] Preparation Example 2: This preparation example provides a method for preparing pre-dried functional powder A2, including the following steps: (1) In a stirring container with a heating jacket, add 2000g of epoxidized soybean oil, heat to 55°C, then add 40g of calcium stearate, stir for 15 minutes until the calcium stearate is evenly dispersed in the oil phase to form a modified oil solution. (2) Put 1000g of fumed silica into the main chamber of the high-speed mixer, start the agitator, and set the speed to 1500rpm; (3) The modified oil prepared in step (1) is sprayed into the high-speed mixer chamber through a high-pressure atomizing nozzle. The spraying rate is controlled so that the oil is sprayed out within 5 minutes. The material temperature is maintained at 55°C by using shear friction heat. (4) After the oil is sprayed, continue mixing at 1500 rpm for 3 minutes until the material is loose, free of lumps and has free flow dry powder state. Discharge and seal the package to obtain pre-dried functional powder A2.

[0054] Preparation Example 3: This preparation example provides a method for preparing pre-dried functional powder A3, including the following steps: (1) In a stirring container with a heating jacket, add 2800g of epoxidized soybean oil, heat to 60°C, then add 60g of calcium stearate, stir for 15 minutes until the calcium stearate is evenly dispersed in the oil phase to form a modified oil solution. (2) Put 1000g of fumed silica into the main chamber of the high-speed mixer, start the stirring paddle, and set the speed to 1800rpm; (3) The modified oil prepared in step (1) is sprayed into the high-speed mixer chamber through a high-pressure atomizing nozzle. The spraying rate is controlled so that the oil is sprayed out within 8 minutes. The material temperature is maintained at 65°C by using shear friction heat. (4) After the oil is sprayed, continue mixing at 1800 rpm for 5 minutes until the material is loose, free of lumps and has free flow dry powder state. Discharge and seal the package to obtain pre-dried functional powder A3.

[0055] Preparation Example 4: This preparation example provides a method for preparing pre-dried functional powder A4, including the following steps: (1) In a stirring container with a heating jacket, add 2500g of epoxidized soybean oil, heat to 55°C, then add 30g of calcium stearate, stir for 15 minutes until the calcium stearate is evenly dispersed in the oil phase to form a modified oil solution. (2) Put 1000g of fumed silica into the main chamber of the high-speed mixer, start the agitator, and set the speed to 1500rpm; (3) The modified oil prepared in step (1) is sprayed into the high-speed mixer chamber through a high-pressure atomizing nozzle. The spraying rate is controlled so that the oil is sprayed out within 6 minutes. The material temperature is maintained at 60°C by using shear friction heat. (4) After the oil is sprayed, continue mixing at 1500 rpm for 4 minutes until the material is loose, free of lumps and free-flowing dry powder. Discharge and seal the package to obtain pre-dried functional powder A4.

[0056] Example 1: This embodiment provides a method for preparing a high-temperature and oil-resistant electrical equipment cable. The raw material composition of the cable material (by weight) is as follows: 50 parts HNBR, 50 parts EVM, 20 parts ZDMA, 1.0 part AMSD, 115 parts pre-dried functional powder A1, 0.5 parts BHT, 5 parts active magnesium oxide, 2 parts antioxidant, 3.5 parts DCP, 1.0 part TAIC, and 4 parts calcium oxide masterbatch (CaO-80).

[0057] The preparation method includes the following steps: S1. Prefabrication of cable core: Select tinned copper conductors that meet the standards, and extrude an insulation layer on the outer layer to make insulated wire cores; twist multiple insulated wire cores according to design requirements, fill the gaps with filler, wrap with wrapping tape, and make a round cable core for later use. S2, High-Temperature Kinetic Dispersion Mixing (Section A): Preheat the internal mixer to 90°C, set the rotor speed to 60 rpm, add HNBR and EVM rubber compounds, and simultaneously add antioxidant, active magnesium oxide and anti-scorching agent BHT, and mix for 1.5 minutes; then add ZDMA, AMSD and pre-dried functional powder A1, increase the top jack pressure to 0.6 MPa and increase the rotor speed to 80 rpm, rapidly raise the rubber compound temperature to 140°C within 2 minutes, and mix at this temperature for 3 minutes, then discharge the rubber to obtain Section A compound; S3. Low-temperature vulcanization compounding (Section B): Transfer the Section A compound to the open mill, adjust the roller gap to 1.5mm for thin-pass heat dissipation, and reduce the temperature of the rubber compound to 70℃; add DCP, TAIC and calcium oxide masterbatch, and perform triangular wrapping and left and right cutting operations 5 times each to ensure uniform dispersion; adjust the roller gap to 4mm for sheeting, and let it stand at room temperature for 12 hours to obtain the sheath-specific compound; S4. Extrusion and crosslinking: The sheath-specific compound obtained in step S3 is added to a cold-feed extruder and uniformly extruded through the die head mold to wrap the outermost layer of the cable core prefabricated in step S1; then it is fed into a 180°C continuous vulcanization pipeline for continuous vulcanization and crosslinking, with the steam pressure maintained at 1.4 MPa. After cooling and drying, a high-temperature and oil-resistant electrical equipment-specific cable is obtained.

[0058] Example 2: This embodiment provides a method for preparing a high-temperature and oil-resistant electrical equipment cable. The raw material composition of the cable material (by weight) is as follows: 60 parts HNBR, 40 parts EVM, 18 parts ZDMA, 0.8 parts AMSD, 12 parts pre-dried functional powder A2, 0.4 parts BHT, 4 parts active magnesium oxide, 2 parts antioxidant, 3.0 parts DCP, 0.8 parts TAIC, and 3 parts calcium oxide masterbatch (CaO-80).

[0059] The preparation method includes the following steps: S1. Prefabrication of cable core: Select tinned copper conductors that meet the standards, and extrude an insulation layer on the outer layer to make insulated wire cores; twist multiple insulated wire cores according to design requirements, fill the gaps with filler, wrap with wrapping tape, and make a round cable core for later use. S2, High-Temperature Kinetic Dispersion Mixing (Section A): Preheat the internal mixer to 90°C and speed to 60 rpm. Add HNBR, EVM, antioxidant, magnesium oxide and BHT, and mix for 1 minute. Add ZDMA, AMSD and pre-dried functional powder A2, increase the pressure to 0.7 MPa and speed to 85 rpm, raise the glue temperature to 138°C, and mix at a constant temperature for 4 minutes. Discharge the glue to obtain Section A compound. S3, Low-temperature vulcanization compounding (Section B): The Section A compound is cooled to 75°C on a two-roll mill; DCP, TAIC and calcium oxide masterbatch are added, and the mixture is mixed evenly and then rolled into triangular pieces 5 times; the mixture is sheeted out and cured for 8 hours to obtain the special compound for sheathing. S4. Extrusion and cross-linking: The sheath-specific compound obtained in step S3 is added to a cold-feed extruder and uniformly extruded through the die head mold to wrap the outermost layer of the cable core prefabricated in step S1; then it is fed into a continuous vulcanization pipeline at 178°C for continuous vulcanization and cross-linking, with the steam pressure maintained at 1.3MPa. After cooling and drying, a high-temperature and oil-resistant electrical equipment-specific cable is obtained.

[0060] Example 3: This embodiment provides a method for preparing a high-temperature and oil-resistant electrical equipment cable. The raw material composition of the cable material (by weight) is as follows: 40 parts HNBR, 60 parts EVM, 25 parts ZDMA, 1.2 parts AMSD, 18 parts pre-dried functional powder A3, 0.6 parts BHT, 6 parts active magnesium oxide, 2.5 parts antioxidant, 4.0 parts DCP, 1.5 parts TAIC, and 5 parts calcium oxide masterbatch (CaO-80).

[0061] The preparation method includes the following steps: S1. Prefabrication of cable core: Select tinned copper conductors that meet the standards, and extrude an insulation layer on the outer layer to make insulated wire cores; twist multiple insulated wire cores according to design requirements, fill the gaps with filler, wrap with wrapping tape, and make a round cable core for later use. S2, High-Temperature Kinetic Dispersion Mixing (Section A): Preheat the internal mixer to 90°C and speed to 60 rpm. Add HNBR, EVM, antioxidant, magnesium oxide, and BHT, and mix for 1.5 minutes. Add ZDMA, AMSD, and pre-dried functional powder A3. Increase the pressure to 0.8 MPa and speed to 90 rpm. Raise the rubber temperature to 142°C and mix at a constant temperature for 3 minutes. Discharge the rubber to obtain Section A compound. S3, Low-temperature vulcanization compounding (Section B): The Section A compound is cooled to 65°C on a two-roll mill; DCP, TAIC and calcium oxide masterbatch are added and mixed evenly, and cut 6 times from left and right; sheet out and cure for 24 hours to obtain the special compound for sheathing. S4. Extrusion and cross-linking: The special compound rubber for sheathing obtained in step S3 is added to a cold feed extruder and evenly extruded through the die head mold to wrap the outermost layer of the cable core prefabricated in step S1; then it is fed into a continuous vulcanization pipeline at 185°C for continuous vulcanization and cross-linking, with the steam pressure maintained at 1.5MPa. After cooling and drying, a high-temperature resistant and oil-resistant special cable for electrical equipment is obtained.

[0062] Example 4: This embodiment provides a method for preparing a high-temperature and oil-resistant electrical equipment cable. The raw material composition of the cable material (by weight) is as follows: 50 parts HNBR, 50 parts EVM, 25 parts ZDMA, 1.5 parts AMSD, 115 parts pre-dried functional powder A1, 0.5 parts BHT, 5 parts active magnesium oxide, 2 parts antioxidant, 3.5 parts DCP, 1.2 parts TAIC, and 4 parts calcium oxide masterbatch (CaO-80).

[0063] The preparation method includes the following steps: S1. Prefabrication of cable core: Select tinned copper conductors that meet the standards, and extrude an insulation layer on the outer layer to make insulated wire cores; twist multiple insulated wire cores according to design requirements, fill the gaps with filler, wrap with wrapping tape, and make a round cable core for later use. S2, High-Temperature Kinetic Dispersion Mixing (Section A): Preheat the internal mixer to 90°C and speed to 60 rpm. Add HNBR, EVM, antioxidant, magnesium oxide, and BHT, and mix for 1.5 minutes. Add ZDMA, AMSD, and pre-dried functional powder A1. Increase the pressure to 0.8 MPa and speed to 95 rpm. Raise the rubber temperature to 145°C and mix at a constant temperature for 3 minutes. Discharge the rubber to obtain Section A compound. S3, Low-temperature vulcanization compounding (Section B): The Section A compound is cooled to 70°C on a two-roll mill; DCP, TAIC and calcium oxide masterbatch are added and mixed evenly; sheeting is done and cured for 12 hours to obtain the special compound for sheathing. S4. Extrusion and cross-linking: The sheath-specific compound obtained in step S3 is added to a cold-feed extruder and uniformly extruded through the die head mold to wrap the outermost layer of the cable core prefabricated in step S1; then it is fed into a continuous vulcanization pipeline at 182°C for continuous vulcanization and cross-linking, with the steam pressure maintained at 1.4 MPa. After cooling and drying, a high-temperature and oil-resistant electrical equipment-specific cable is obtained.

[0064] Example 5: This embodiment provides a method for preparing a high-temperature and oil-resistant electrical equipment cable. The raw material composition of the cable material (by weight) is as follows: 55 parts HNBR, 45 parts EVM, 22 parts ZDMA, 0.6 parts AMSD, 15 parts pre-dried functional powder A4, 0.5 parts BHT, 5 parts active magnesium oxide, 2 parts antioxidant, 3.5 parts DCP, 1.0 part TAIC, and 4 parts calcium oxide masterbatch (CaO-80).

[0065] The preparation method includes the following steps: S1. Prefabrication of cable core: Select tinned copper conductors that meet the standards, and extrude an insulation layer on the outer layer to make insulated wire cores; twist multiple insulated wire cores according to design requirements, fill the gaps with filler, wrap with wrapping tape, and make a round cable core for later use. S2, High-Temperature Kinetic Dispersion Mixing (Section A): Preheat the internal mixer to 85°C and speed to 55 rpm. Add HNBR, EVM, antioxidant, magnesium oxide and BHT, and mix for 1 minute. Add ZDMA, AMSD and pre-dried functional powder A4, increase the pressure to 0.7 MPa and speed to 75 rpm, raise the glue temperature to 136°C, and mix at a constant temperature for 5 minutes. Discharge the glue to obtain Section A compound. S3, Low-temperature vulcanization compounding (Section B): The Section A compound is cooled to 70°C on a two-roll mill; DCP, TAIC and calcium oxide masterbatch are added and mixed evenly; sheeting is done and cured for 12 hours to obtain the special compound for sheathing. S4. Extrusion and crosslinking: The sheath-specific compound obtained in step S3 is added to a cold-feed extruder and uniformly extruded through the die head mold to wrap the outermost layer of the cable core prefabricated in step S1; then it is fed into a 180°C continuous vulcanization pipeline for continuous vulcanization and crosslinking, with the steam pressure maintained at 1.4 MPa. After cooling and drying, a high-temperature and oil-resistant electrical equipment-specific cable is obtained.

[0066] Comparative Example 1: Compared with Example 1, the difference is that the pre-prepared dried functional powder A1 is not used. Instead, equal parts by weight of fumed silica, epoxidized soybean oil (ESO), and calcium stearate are directly added to the internal mixer during the mixing process in section A, while the rest of the formulation and process steps are the same.

[0067] Comparative Example 2: The difference from Example 1 is that α-methylstyrene dimer (AMSD) is not added to the formulation, while the rest of the formulation and process steps are the same.

[0068] Comparative Example 3: Compared with Example 1, the difference is that calcium stearate is not added when preparing the pre-dried functional powder, while the rest of the formulation and process steps are the same.

[0069] Comparative Example 4: Compared with Example 1, the difference is that the mixing process of section A is changed, the mixing temperature is controlled to always be below 110°C (ZDMA is not melted), and mechanical dispersion is achieved by extending the mixing time to 10 minutes. The rest of the formula is the same.

[0070] Comparative Example 5: Compared with Example 1, the difference is that ZDMA and AMSD are not used, but are replaced with N550 carbon black in equal amounts; at the same time, pre-dried powder is not used, but an equal amount of liquid ESO is directly added as a plasticizer, and the other components are the same.

[0071] Test Example 1: Test Description: This test aims to verify the material's ability to self-heal and maintain its properties in an acidic oil environment.

[0072] Test steps: Use standard IRM 903 oil resistance test oil as the base medium, add 0.5% oleic acid (AR grade purity) to it, and mechanically stir for 30 minutes to mix it evenly to prepare a simulated acidic aging oil solution.

[0073] The vulcanized rubber sheets prepared in Example 1 and Comparative Example 3 were selected and cut into Type II dumbbell-shaped specimens according to GB / T 528 standard. Five parallel specimens were prepared for each group, and the initial tensile strength and elongation at break before aging were measured at room temperature. The average value was taken as the reference data.

[0074] The above samples were completely immersed in a glass container filled with simulated acidic aging oil, with no contact between the samples or with the container wall. The samples were placed in a forced-air drying oven and subjected to an immersion aging test at 150°C for 168 hours.

[0075] After aging, the sample was removed and allowed to cool naturally to room temperature. The surface oil was wiped off with filter paper, and after standing for 4 hours, the tensile strength and elongation at break after aging were measured using a tensile testing machine, and the performance retention rate was calculated.

[0076] The test data is shown in Table 1: Table 1: Performance test data of simulated acidic oil aging (150℃×168h) (Note: The data in Table 1 are the average values ​​of the test results of 5 parallel samples, without rounding, preserving the original experimental fluctuation characteristics.) According to the appendix Figure 1According to the data in Table 1, Example 1 maintained a tensile strength retention rate of 88.9% and an elongation at break retention rate of 82.3% after aging in simulated acidic oil; while Comparative Example 3 maintained a tensile strength retention rate of only 63.6% and an elongation at break retention rate that dropped significantly to 55.0%.

[0077] The data discrepancies confirmed the chemical activity of calcium stearate in the system during the aging process. In Comparative Example 3, due to the lack of acid-responsive components, high temperature and oleic acid medium penetration led to thermo-oxidative degradation of the HNBR / EVM matrix. Acidic substances further catalyzed ester hydrolysis and main chain breakage, which macroscopically manifested as a significant decrease in mechanical properties and minimal change in tensile stress, indicating that no effective re-crosslinking occurred.

[0078] In contrast, Example 1 utilizes the latent calcium stearate within the pre-formed powder to achieve performance self-stabilization. When external oleic acid molecules penetrate the material, they preferentially undergo a displacement reaction with calcium stearate, generating free calcium ions that act as Lewis acid catalysts. This catalyst in situ activates epoxidized soybean oil (ESO) anchored on the silica surface, promoting ring-opening polymerization of residual epoxy groups with the polar side groups of the EVM matrix, carboxyl groups generated from hydrolysis, or ESO itself. This newly formed chemical crosslinking network triggered by aging products effectively repairs or compensates for network defects caused by main chain breakage, thereby maintaining the structural integrity of the material under harsh operating conditions. In Example 1, the 100% tensile stress showed a significant increase (+17.4%) after aging, further confirming that this secondary crosslinking enhancement reaction occurred during the aging process.

[0079] Test Example 2: Test Description: This test aims to evaluate the effects of different component systems and process conditions on the initial physical and mechanical properties and heat aging stability of the material.

[0080] Test steps: According to GB / T528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber", the vulcanized rubber sheets prepared in Examples 1-5 and Comparative Examples 2, 4 and 5 were cut into I-shaped dumbbell specimens. The initial tensile strength, elongation at break and 100% constant elongation stress were tested using a tensile testing machine at a tensile rate of 500 mm / min.

[0081] According to GB / T 531.1-2008 "Test Method for Indentation Hardness of Vulcanized Rubber or Thermoplastic Rubber", the initial hardness of the material was determined using a Shore A hardness tester, and the average value was taken for 5 points of each sample.

[0082] According to GB / T 3512-2014 "Accelerated Aging and Heat Resistance Test of Vulcanized Rubber or Thermoplastic Rubber in Hot Air", the samples were suspended in a heat aging test chamber and subjected to hot air aging treatment at 165℃ for 168 hours, with forced air circulation during the aging process.

[0083] After aging, the sample was removed and conditioned for 24 hours in a standard laboratory environment (23±2℃). Its tensile strength and elongation at break were tested again, and the performance change rate after aging was calculated.

[0084] The test data is shown in Table 2: Table 2: Basic physical and mechanical properties and hot air aging (165℃×168h) test data According to the appendix Figure 2 According to the data in Table 2, the initial tensile strength of Examples 1-5 is above 23.8 MPa, with the highest reaching 26.4 MPa (Example 4). After rigorous heat aging at 165℃ for 168h, the change rate of tensile strength is controlled between -4.5% and -7.2%, demonstrating excellent mechanical properties and heat resistance stability.

[0085] Comparative Example 2 (without AMSD) showed an initial tensile strength reduced to 17.6 MPa and an elongation at break of only 285%. This is because, lacking the regulation of the chain transfer agent AMSD, ZDMA underwent excessive homopolymerization during high-temperature mixing, forming large ZDMA aggregates. These large particles could not serve as effective nano-reinforcing points; instead, they became stress concentration sources in the matrix, leading to premature fracture of the material during tensile testing. Simultaneously, due to the lack of fine and uniformly distributed ionic crosslinking points, the material's thermal stability decreased, resulting in a significant strength loss after aging (-15.9%).

[0086] Comparative Example 4 (low-temperature process) exhibited the worst performance, with an initial tensile strength of only 10.2 MPa, which decreased sharply after aging. This confirms the necessity of a high-temperature kinetic dispersion process above 135°C. Under low-temperature conditions, ZDMA failed to reach a molten state, making molecular-level dispersion and in-situ reaction impossible; it existed only as a common inert filler in the rubber. Due to the lack of a dual network of chemical and ionic bonds, the material could not resist thermal and oxidative attack, leading to the rapid collapse of its microstructure during aging.

[0087] Although Comparative Example 5 (carbon black / liquid oil system) had a decent initial strength (19.8 MPa), it was significantly lower than the 24.3 MPa of Example 1. Furthermore, its tensile strength decreased by 18.2% after aging, and its elongation at break decreased by more than 35%. This indicates that the rigid ionic network constructed by in-situ polymerization of ZDMA has higher thermal stability compared to the traditional physical reinforcing network of carbon black. In addition, the examples introduced plasticizers through pre-dried powder, which, compared to the direct addition of liquid oil in Comparative Example 5, reduced the volume shrinkage and performance degradation caused by the volatilization and migration of small molecule plasticizers during aging.

[0088] Test Example 3: Test Description: This test evaluates the volume stability and resistance to plasticizer extraction of materials in high-temperature oil media by comparing the mass and volume changes of materials prepared under different processes in a standard oil resistance test.

[0089] Experimental steps: According to GB / T 1690-2010 "Test Method for Liquid Resistance of Vulcanized Rubber or Thermoplastic Rubber", rectangular specimens with dimensions of 25mm×50mm×2.0mm were cut from the vulcanized rubber sheets prepared in Examples 1-5 and Comparative Examples 1 and 5. Three parallel specimens were prepared for each group, and holes were punched at the top of the specimens for hanging.

[0090] The initial mass of the sample in air was weighed using an analytical balance with an accuracy of 0.1 mg. Then, the initial mass of the sample in distilled water was determined using Archimedes' displacement method. The initial volume of the sample was calculated using the density formula. At the same time, the initial hardness of the sample before immersion was determined using a Shore A hardness tester.

[0091] The sample is suspended and completely immersed in a glass test tube containing standard IRM 903 oil resistance test oil (highly swelling mineral oil). The test tube is placed in an aluminum bath heating device and continuously immersed for 168 hours at a constant temperature of 150°C, ensuring that the samples do not come into contact with each other or touch the container wall, and the ratio of oil volume to sample volume is greater than 15:1.

[0092] After soaking, remove the sample and cool it at room temperature for 30 minutes. Then, quickly immerse it in acetone for 10 seconds to remove the oil adhering to the surface. Wipe the surface gently with lint-free filter paper and immediately weigh the mass in the air and the mass in the water after soaking. Calculate the rate of change of mass and the rate of change of volume. After standing for 2 hours, measure the hardness of the sample again and calculate the change in hardness.

[0093] The test data is shown in Table 3: Table 3: Immersion performance test data of IRM 903 oil (150℃×168h) According to the appendix Figure 3According to the data in Table 3, Examples 1-5 exhibited dimensional stability and resistance to extraction after being immersed in oil at 150°C for 168 hours. Their mass change rate remained within a positive range of +1.5% to +2.8%, their volume change rate was +2.6% to +4.2%, and their hardness change was minimal (0 to +2 degrees). This indicates that only slight oil molecule swelling occurred in the materials of these examples, and no significant migration or loss of the plasticizer ESO occurred within the system.

[0094] The test results for Comparative Example 1 (direct mixing process) showed a completely different trend, with a mass change rate of -4.3%, a volume change rate of -2.1% (shrinkage), and an increase in hardness of 9 degrees. The negative growth in mass and volume in IRM 903, a medium that typically causes rubber swelling, directly confirms severe plasticizer extraction within the material. Because Comparative Example 1 did not employ pre-dried powder technology, the liquid ESO was not effectively physically adsorbed by the nanopores of fumed silica, nor did it undergo chemical grafting with silanol groups at high temperatures via calcium stearate catalysis. The free ESO rapidly migrated to the external medium in the high-temperature oil bath, leading to shrinkage of the rubber compound. Simultaneously, with the loss of plasticizer, the lubrication between rubber molecular chains weakened, resulting in a significant increase in material hardness and a loss of its original flexibility.

[0095] Comparative Example 5 (traditional liquid addition) performed the worst, with a mass loss of -6.8% and a sharp increase in hardness of 12 degrees. This further verifies the effectiveness of the "fumed silica-ESO-ZDMA" ternary anchoring mechanism. In the example scheme, not only is physical oil locking achieved by utilizing the pores of silica, but more importantly, a dense ion cluster layer formed by in-situ polymerization of ZDMA in the internal mixing stage A (140℃) is used to construct a labyrinth effect that blocks the entry and exit of oil molecules. Combined with chemically grafted ESO, this solves the technical problem of hardening and cracking of traditional oil-resistant cable materials due to plasticizer precipitation.

[0096] Test Example 4: Test Description: This test aims to examine the impact of different raw material pretreatment methods and processing techniques on the appearance quality of finished cable materials.

[0097] Test steps: Cylindrical samples approximately 10 cm long were cut from the finished cable materials prepared in Examples 1-5 and Comparative Examples 1, 4, and 5, and corresponding 2 mm thick vulcanized test pieces were prepared.

[0098] Oil penetration test (filter paper method): Place the vulcanized test piece between two sheets of qualitative filter paper, with a flat steel plate underneath and on top of each piece, and apply a 1kg standard weight. Place the entire apparatus in a 70℃ forced-air drying oven for 24 hours. After removal, remove the weight and test piece, and observe the oil adsorption on the filter paper surface under natural light. Grade the filter paper based on the percentage of oil stain area: Grade 1: No visible oil stains; Grade 2: Only scattered dots of oil; Grade 3: Localized patchy oil stains; Grade 4: Filter paper is heavily soaked; Grade 5: Filter paper is completely wet and transparent.

[0099] Appearance and cross-sectional density inspection: Under sufficient light, visually observe the surface smoothness of the extruded sample and record whether there is a grainy texture or flow marks. Then, use a sharp blade to cut the sample radially and observe the cross-section using a 5x magnifying glass, recording whether there are visible pores, microcracks, or obvious filler agglomeration white spots.

[0100] Based on the above observations, the performance of each group in three dimensions—anti-permeability, surface smoothness, and cross-sectional density—was recorded.

[0101] The test data is shown in Table 4: Table 4: Surface Exudability and Appearance Quality Assessment Results (Note: The lower the oil penetration grade, the better the anti-migration performance; surface condition reflects the uniformity of dispersion; cross-sectional density reflects the moisture absorption and defoaming effect.) According to the data in Table 4, Examples 1-5 showed advantages in appearance quality control, with their oil penetration levels mainly concentrated at Grade 1 (no visible oil stains). Only Example 3 (high oil content formulation) showed slight Grade 2 traces. Furthermore, the surfaces of all sample examples were smooth and delicate, with dense cross-sections free of pores. This indicates that by pre-locking liquid ESO within the nanopores of fumed silica through a pre-drying process, combined with high-temperature chemical grafting, the Brownian motion of plasticizer molecules was successfully restricted, making it difficult for them to migrate to the material surface under hot-pressing conditions. Simultaneously, the CaO masterbatch in the formulation effectively absorbed trace amounts of moisture from the raw materials, preventing foaming during high-temperature extrusion.

[0102] Comparative Example 1 (direct mixing process) achieved an oil seepage level of 4, with a sticky feel on the sample surface. During stage A mixing, without pre-drying, the high specific surface area of ​​fumed silica preferentially entangles with the rubber matrix or ZDMA, resulting in insufficient ESO filling of its pores. Free ESO molecules are thermodynamically unstable in the rubber network and readily migrate to the surface along the concentration gradient under 70℃ hot-pressing conditions, causing severe "oil spraying" defects. This will significantly affect the printability and long-term insulation resistance of the cable sheath.

[0103] Although Comparative Example 4 (low-temperature mixing) showed less oil seepage (level 2), its surface condition was described as "rough with visible fine protrusions," and "white granular dots" were observed on the cross-section. This is because the mixing temperature (<110℃) did not reach the melting point of ZDMA (approximately 130℃), preventing ZDMA from melting, dispersing, and participating in the polymerization reaction. Instead, it filled the rubber as coarse crystalline particles. These micron-sized agglomerates disrupted the continuous phase of the material, leading to increased surface roughness during extrusion. This not only affected the aesthetics but also became a weak point for stress concentration.

[0104] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-temperature and oil-resistant cable for electrical equipment, characterized in that, It includes a cable core and a sheath covering the outside of the cable core, the sheath being made of raw materials comprising the following parts by weight: Hydrogenated nitrile butadiene rubber: 40-60 parts; Ethylene-vinyl acetate rubber: 40-60 parts; Zinc dimethacrylate: 18-25 parts; α-Methylstyrene dimer: 0.6-1.5 parts; Pre-dried functional powder: 12-18 parts; Anti-scorching agent: 0.4-0.6 parts; Activated magnesium oxide: 4-6 parts; Anti-aging agent: 2-2.5 parts; Dicumyl peroxide: 3.0-4.0 parts; Triallyl isocyanurate: 0.8-1.5 parts; Calcium oxide masterbatch: 3-5 parts.

2. The high-temperature and oil-resistant electrical equipment cable according to claim 1, characterized in that, In the raw material of the sheath layer: The weight parts of hydrogenated nitrile butadiene rubber are 50-55 parts; The weight parts of ethylene-vinyl acetate rubber are 45-50 parts; The weight parts of zinc dimethacrylate are 20-22 parts; The weight parts of α-methylstyrene dimer are 0.8-1.2 parts; The weight parts of the pre-dried functional powder are 15 parts.

3. The high-temperature and oil-resistant electrical equipment cable according to claim 1, characterized in that, The pre-dried functional powder is made of fumed silica, epoxidized soybean oil and calcium stearate, with the weight ratio of fumed silica, epoxidized soybean oil and calcium stearate being 10:20-28:0.3-0.

6.

4. The high-temperature and oil-resistant electrical equipment cable according to claim 1, characterized in that, The pre-dried functional powder is prepared through the following steps: Calcium stearate is dispersed in epoxidized soybean oil heated to 55-60℃ to form a modified oil solution. The modified oil solution is then atomized and sprayed into fumed silica under high-speed stirring. The material temperature is maintained at 55-65℃ by shear friction heat and the mixture is mixed until the material is in a dry powder state.

5. The high-temperature and oil-resistant electrical equipment cable according to claim 1, characterized in that, The scorching inhibitor is 2,6-di-tert-butyl-4-methylphenol; the antioxidant is 4,4'-bis(α,α-dimethylbenzyl)diphenylamine.

6. A method for preparing a high-temperature and oil-resistant electrical equipment cable, used to prepare the high-temperature and oil-resistant electrical equipment cable according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Select a conductor and extrude an insulation layer on its outer layer to obtain an insulated wire core. Twist and fill the insulated wire core into a cable to obtain the cable core. S2. Hydrogenated nitrile rubber, ethylene-vinyl acetate rubber, antioxidant, active magnesium oxide and scorch inhibitor are mixed in an internal mixer. Then zinc dimethacrylate, α-methylstyrene dimer and pre-dried functional powder are added. The mixture is heated and mixed at a constant temperature of 136-145℃ to obtain the A-section compound. S3. Cool the A-section compound to 65-75℃, add dicumyl peroxide, triallyl isocyanurate and calcium oxide masterbatch, mix evenly and then sheet to obtain the sheath-specific compound. S4. The special compound rubber for sheathing obtained in step S3 is extruded onto the outer layer of the cable core prefabricated in step S1, and then subjected to high-temperature vulcanization crosslinking to obtain the finished cable.

7. The method for preparing a high-temperature and oil-resistant electrical equipment cable according to claim 6, characterized in that, In step S1, the pre-prepared dried functional powder is pretreated using the following method: Heat epoxidized soybean oil to 55-60℃ in a stirring container, add calcium stearate and stir to disperse for 15 minutes to obtain a mixture; Fumed silica is fed into a high-speed mixer, and the resulting mixture is sprayed through a high-pressure atomizing nozzle at a speed of 1500-1800 rpm. Control the oil spraying time to 5-8 minutes and use shear heat to maintain the temperature at 55-65℃. After the oil spraying is completed, continue mixing for 3-5 minutes until the material is discharged.

8. The method for preparing a high-temperature and oil-resistant electrical equipment cable according to claim 6, characterized in that, The process parameters for step S2 are controlled as follows: After adding zinc dimethacrylate, α-methylstyrene dimer and pre-dried functional powder, increase the pressure of the top plug of the internal mixer to 0.6-0.8 MPa, and at the same time increase the rotor speed to 75-95 rpm. Within 2 minutes, raise the temperature of the rubber compound to 136-145℃, and the constant temperature mixing time is 3-5 minutes.

9. The method for preparing a high-temperature and oil-resistant electrical equipment cable according to claim 6, characterized in that, Step S3 further includes: Transfer the A-section compound to the open mill and adjust the roller gap to 1.5mm for thin-pass heat dissipation; When the temperature of the rubber compound drops to 65-75℃, add dicumyl peroxide, triallyl isocyanurate and calcium oxide masterbatch; Then perform the triangular wrapping and left and right cutting operations 5-6 times each, adjust the roller gap to 4mm for sheeting, and cure at room temperature for 8-24 hours.

10. The method for preparing a high-temperature and oil-resistant electrical equipment cable according to claim 6, characterized in that, In step S4, the crosslinking temperature is controlled at 178-185℃ and the steam pressure is controlled at 1.3-1.5MPa.

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