Anti-rust cable accessory insulation lubricating grease and preparation method thereof

Abstract

The present application relates to the technical field of power cable, especially relates to a rust-proof cable accessory insulation lubricating grease and a preparation method thereof, which comprises 100 parts of base oil, 8-25 parts of modified fumed silica, 0.01-3 parts of extreme pressure anti-wear agent and 0.1-1 part of antioxidant by weight fraction. The present application realizes double function integration by simultaneously constructing benzotriazole corrosion inhibition group and diphenylsilane insulation barrier on the surface of fumed silica. The triazole ring of benzotriazole is oriented exposed on the surface of the filler, and a dense passivation film is formed by the coordination of lone pair electrons and metal atoms, thereby blocking the electrochemical corrosion path from the molecular level; the rigid aromatic ring of diphenylsilane inhibits electron migration through steric hindrance effect, thereby forming a high-energy barrier insulation layer. The two are stably combined through siloxane covalent bond, thereby solving the performance conflict caused by the phase separation of rust inhibitor and insulation agent in the traditional physical mixing process, and long-acting synergistic protection ability is given to the lubricating grease.

Description

Technical Field

[0001] This invention relates to the field of power cable technology, and in particular to a rust-preventive cable accessory insulating grease and its preparation method. Background Technology

[0002] Cable accessory insulating grease is a key material for ensuring the safe operation of power cable connection systems. It is specifically designed for use in harsh environments such as cable terminals and joints where high electric fields, mechanical vibrations, and corrosive conditions coexist. Its core function is to achieve long-term protection through the synergistic effect of three functions: First, as an electrically stable medium, it fills microscopic defects at the interface to homogenize the electric field distribution and eliminate the risk of partial discharge; second, it forms a molecular-level anti-rust barrier, building a passivation film on the conductor metal surface to block water and oxygen erosion and inhibit electrochemical corrosion; and third, it plays a dynamic stress buffering role, absorbing thermomechanical stress with its thixotropic properties, reducing insertion and extraction wear, and sealing and isolating contaminants. This ensures the insulation integrity, metal protection, and mechanical reliability of high-voltage cable systems under complex operating conditions, providing a fundamental guarantee for power grid safety.

[0003] Chinese patent CN110591386B discloses a curable insulating vinyl silicone grease material, its preparation method, and its uses, belonging to the field of power cable technology. This curable insulating vinyl silicone grease material is cured from vinyl silicone oil, silica, side-containing hydrogen silicone oil, end-containing hydrogen silicone oil, inhibitor, and catalyst in a mass ratio of 100:(5-50):(0.1-20):(0.1-20):(0.01-1):(0.005-1). This curable insulating vinyl silicone grease material is an addition-type polyorganosiloxane, possessing excellent lubricity and water resistance, and can be used as an interface coating between cable accessories and power cables. Due to its excellent electrical properties and appropriate pre-curing viscosity, this curable insulating vinyl silicone grease material can continue to cure after being applied between the cable accessories and the power cable, thereby improving interface breakdown strength and water resistance. Furthermore, since curing does not produce small molecule byproducts, it avoids volume shrinkage and bubble formation, thus preventing swelling of silicone rubber and extending the service life of cable accessories. However, this technology mainly focuses on the swelling of silicone grease and the poor thixotropy of silicone gel. It still has shortcomings in the rust prevention performance of grease, especially in harsh working environments where it is easily corroded by water, salt and other corrosive substances, which can lead to a decline in the performance of grease and affect the insulation effect and service life of cable accessories. Summary of the Invention

[0004] In view of this, the present invention proposes a rust-preventive cable accessory insulating grease and its preparation method to solve the problem of insufficient rust prevention performance of existing cable accessory insulating greases. This rust-preventive cable accessory insulating grease has good corrosion resistance and can maintain stable insulation performance and lubrication effect for a long time in harsh working environments, thereby extending the service life of cable accessories and improving the safety and reliability of power systems.

[0005] The technical solution of the present invention is achieved as follows: The present invention provides a rust-preventive cable accessory insulating grease, which, by weight, comprises 100 parts of base oil, 8-25 parts of modified fumed silica, 0.01-3 parts of extreme pressure anti-wear agent, and 0.1-1 parts of antioxidant.

[0006] The rust-preventive cable accessory insulating grease provided by this invention achieves a multi-functional synergistic enhancement effect. This grease is based on a benzotriazole-diphenylsilane composite functional layer constructed on the surface of modified fumed silica, simultaneously achieving a dual protection mechanism of metal passivation and electron migration barrier—the benzotriazole groups form a dense molecular-level rust-preventive film through lone pair electron coordination, blocking the electrochemical corrosion path; the rigid aromatic ring of diphenylsilane effectively inhibits interfacial charge accumulation. Furthermore, nano-zinc molybdate is embedded into the silane network through physical adsorption, and its molybdate ions deposit a restorative inorganic phase in the corrosion micro-regions, forming a layered synergistic protection with the organic passivation film, significantly improving durability under humid, hot, and salt spray environments. This design simultaneously optimizes the thermomechanical stability of the material: the aromatic ring structure inhibits high-temperature molecular chain movement, allowing the grease to maintain stable thixotropic properties and insulation resistance, solving the problems of sealing failure and insulation fluctuation caused by cable thermal cycling.

[0007] Based on the above technical solutions, preferably, the modified fumed silica is prepared by a one-step silane crosslinking process. The preparation method includes: under nitrogen protection, dispersing fumed silica in anhydrous xylene, adding a mixed silane solution, stirring and heating to 58-62°C, then adding acetic acid dilution dropwise, then heating to 105-115°C, stirring and refluxing for 23-25 ​​hours, adding zinc molybdate and continuing the reaction for 0.9-1.1 hours, filtering, washing, and drying to obtain modified fumed silica.

[0008] Specifically, this one-step silane crosslinking process achieves precise functional construction through a directional hydrolysis-condensation mechanism: Under nitrogen protection, the silanol groups (≡Si-OH) on the surface of fumed silica first undergo selective hydrolysis with the alkoxy groups of diphenyldimethoxysilane and 1-[2-(triethoxysilyl)ethyl]benzotriazole to generate active silanol (≡Si-OR→≡Si-OH); subsequently, under acetic acid catalysis, the silanol and the hydroxyl groups on the silica surface undergo dehydration condensation to form ≡Si-O-Si≡ covalent bonds, while the benzotriazole corrosion inhibitor groups are exposed on the filler surface; the zinc molybdate added in the final stage is embedded into the silane network through physical adsorption to form a molecular-level synergistic protective structure of organic passivation film (BTA)-inorganic repair layer (ZnMoO4), ultimately endowing the material with a triple integration of excellent insulation, corrosion resistance and humid heat stability.

[0009] Based on the above technical solutions, preferably, the mass ratio of the fumed silica to the mixed silane solution is 1:0.15-0.25.

[0010] Specifically, when the silane ratio is too low, insufficient silane coverage leads to residual hydrophilic silanol groups on the surface of fumed silica, which absorb moisture to form a conductive water film, causing a sharp drop in volume resistivity. At the same time, insufficient diphenylsilane grafting rate causes the insulation network to break. When the silane ratio is too high, excessive silane triggers multilayer condensation, deeply burying the benzotriazole corrosion inhibitor groups, preventing the passivation film from contacting the metal and thus losing its rust-preventing function.

[0011] Based on the above technical solutions, preferably, the mixed silane solution is a mixed solution of diphenyldimethoxysilane and 1-[2-(triethoxysilyl)ethyl]benzotriazole, and the mass ratio of diphenyldimethoxysilane to 1-[2-(triethoxysilyl)ethyl]benzotriazole is 1:1.6-4.8.

[0012] When the mass proportion of diphenyldimethoxysilane (DPDMS) in a mixed silane solution is too high, its highly reactive methoxy group (-OCH3) preferentially hydrolyzes and condenses, forming a dense aromatic ring layer on the silica surface. This deeply embeds the benzotriazole (BTA) corrosion-inhibiting group, preventing the triazole ring from contacting the metal interface and thus losing its passivation ability, thereby reducing rust prevention performance. Simultaneously, excess diphenyldimethoxysilane initiates multilayer crosslinking, leading to a decrease in volume resistivity and reduced insulation performance. Conversely, when the mass proportion of 1-[2-(triethoxysilyl)ethyl]benzotriazole (BTA silane) is too high, the DPDMS aromatic ring grafting rate is insufficient, resulting in porosity defects in the insulation network.

[0013] Based on the above technical solutions, preferably, the mass ratio of the acetic acid diluent to the fumed silica is 0.025-0.045:1, the acetic acid diluent is a mixed solution of acetic acid and anhydrous xylene, and the mass ratio of acetic acid to anhydrous xylene is 1:4.9-5.1; the dropping rate of the acetic acid diluent is 0.45-0.55 mL / min.

[0014] Based on the above technical solutions, preferably, the amount of zinc molybdate added is 0.4-0.6 wt% of the fumed silica.

[0015] By introducing zinc molybdate nanoparticles, an organic-inorganic multi-level self-healing and protective system can be constructed. This system embeds itself into a silane network via Si-O-Mo bonds, intelligently releasing molybdate ions (MoO4²⁻) in the corrosion micro-region. These ions form a molecular-level synergy with the benzotriazole organic passivation film—the zinc molybdate deposition of ZnMoO4 inorganic barrier physically blocks chloride ion corrosion, while benzotriazole inhibits anodic dissolution of the metal through coordination bonds. This coupling enhances the anti-rust performance. However, when the zinc molybdate content is too low, the molybdate release concentration is insufficient to effectively cover the damaged micro-region. Conversely, when the zinc molybdate content is too high, it clogs the pores of the insulating framework, shielding the benzotriazole from its corrosion-inhibiting contact and causing a decrease in dielectric strength due to the conductive pathways formed by particle stacking.

[0016] Based on the above technical solutions, preferably, the filtration is thermal filtration, and the thermal filtration temperature is 55-62℃.

[0017] During low-temperature filtration, the ≡Si-O-Si≡ bonds formed by silane condensation are prone to hydrolysis, leading to the breakage of covalent bonds and the release of free silane. At the same time, the sudden change in interfacial tension caused by solvent evaporation forces the benzotriazole corrosion inhibitor group to flip inward, losing its metal passivation ability. On the other hand, excessively high temperatures trigger excessive cross-linking of silane, causing the diphenylsilane aromatic ring to be deeply stacked and embedded with the corrosion inhibitor group, resulting in a sudden drop in surface polarity and the formation of micron-sized aggregates, which destroys its dispersion stability and thixotropic function in the grease.

[0018] Based on the above technical solutions, preferably, the base oil is a long-chain alkyl silicone oil, and the kinematic viscosity of the long-chain alkyl silicone oil at 25°C is 200-1000 cSt.

[0019] Based on the above technical solutions, preferably, the extreme pressure anti-wear agent is one or more of dimer fatty acids, tricresyl phosphate, and triphenyl thiophosphate; and the antioxidant is one or more of diphenylamine, antioxidant 1076, antioxidant 1010, and antioxidant 264.

[0020] This invention also provides a method for preparing a rust-preventive cable accessory insulating grease, the method being used to prepare the rust-preventive cable accessory insulating grease as described above, the method comprising:

[0021] S1. Weigh the base oil, modified fumed silica, extreme pressure anti-wear agent, and antioxidant according to the specified proportions.

[0022] S2. Heat the base oil and modified fumed silica together to 100-110℃, and stir and knead until evenly mixed.

[0023] S3. Add extreme pressure anti-wear agent and antioxidant, start heating and kneading, keep the temperature constant at 128-132℃, vacuum after 80-90 minutes, stir and knead evenly and then stop heating. When the temperature drops below 50℃, stop kneading, cool to room temperature and grind three times on a three-roll mill to obtain rust-proof cable accessory insulating lubricant.

[0024] The rust-preventive cable accessory insulating grease and its preparation method of the present invention have the following advantages over the prior art:

[0025] (1) This invention utilizes a one-step silane crosslinking process to simultaneously construct benzotriazole corrosion inhibitor groups and diphenylsilane insulating barriers on the surface of fumed silica, achieving dual functional integration. The triazole ring of benzotriazole is oriented and exposed on the filler surface, forming a dense passivation film through lone pair electrons coordinating with metal atoms, thus blocking the electrochemical corrosion path at the molecular level; the rigid aromatic ring of diphenylsilane inhibits electron migration through steric hindrance, improving insulation performance. The two are stably combined through siloxane covalent bonds, resolving the performance conflict caused by the phase separation of rust inhibitor and insulating agent in traditional physical mixing processes, and endowing the grease with long-term synergistic protective capabilities.

[0026] (2) This invention introduces zinc molybdate nanoparticles to construct an organic-inorganic multi-level protection system. Zinc molybdate is chemically bonded into a silane network, and its molybdate ions deposit a restorative barrier in the metal corrosion micro-region, forming a synergistic enhancement effect with the benzotriazole organic passivation film: the former blocks chloride ion corrosion, and the latter inhibits anolyte metal dissolution. This design significantly improves the protective durability of the material in harsh environments such as humid heat and salt spray, overcoming the risk of sudden corrosion caused by the environmental failure of traditional rust inhibitors.

[0027] (3) This invention uses acetic acid / xylene diluent to control proton release and maintain the dynamic equilibrium of the hydrolysis-condensation reaction, ensuring that the active sites of benzotriazole face the surface and avoiding the embedding effect caused by excessive cross-linking of insulating silane. At the same time, the rigid aromatic ring structure of diphenylsilane effectively inhibits high-temperature molecular chain movement, reduces interfacial polarization loss, and keeps the grease with stable insulation resistance and rheological properties.

[0028] (4) In this invention, the aggregation tendency caused by hydroxyl groups on the surface of fumed silica is eliminated by long-chain alkyl groups of silane. The functionalized surface and the base oil form a stable colloidal system with similar compatibility, and submicron-level uniform dispersion can be achieved without the addition of external dispersants. This design avoids the negative impact of impurity ions on electrical insulation, maintains the integrity of the seal under the thermomechanical stress of the cable, and provides all-weather protection for the power grid system. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] It should be noted that the fumed silica in this embodiment of the invention was purchased from Guangzhou Haoyi New Material Technology Co., Ltd., model Aerosil 200; and the long-chain alkyl silicone oil was purchased from Shenzhen Jipeng Silicon Fluorine Materials Co., Ltd., model JP-308.

[0031] Example 1

[0032] This embodiment provides a rust-preventive cable accessory insulating grease, which, by weight, comprises 100 parts of long-chain alkyl silicone oil (viscosity 500 cSt), 16.5 parts of modified fumed silica, 1.5 parts of dimer fatty acid, and 0.5 parts of diphenylamine.

[0033] The modified fumed silica was prepared as follows: 20g of fumed silica (specific surface area 200±10 m² / g) was placed in a vacuum drying oven and dried at 120°C for 12 hours to remove physically adsorbed water. The dried fumed silica was then added to a ball mill jar with 200g of zirconia grinding balls (5mm in diameter) and milled at 300 rpm for 2 hours to obtain pretreated fumed silica. Nitrogen gas was introduced into a three-necked flask at a rate of 1L / min. After 30min, the pretreated 20g of fumed silica and 200mL of anhydrous xylene were added to the nitrogen-protected three-necked flask, and ultrasonic dispersion was initiated for 30min to form a uniform suspension. 3.05g of 1-[2-(triethoxysilyl)ethyl]benzotriazole and 0.95g of diphenyldimethoxysilane were weighed into a drying beaker and gently shaken to obtain a mixed silane solution. Measure 0.12 g of glacial acetic acid and add it to 0.6 g of anhydrous xylene. Mix well and transfer to a constant pressure dropping funnel. Add the mixed silane solution to a three-necked flask, heat to 60°C and stir at 300 rpm. Add diluted acetic acid dropwise at a rate of 0.5 mL / min. After the addition is complete, heat to 110°C, turn on the water separator, and stir under reflux for 24 hours. Add 0.1 g of zinc molybdate and continue the reaction for 1 hour. Nitrogen gas is continuously introduced at a rate of 1 L / min throughout the entire reaction. After the reaction is complete, allow it to cool naturally until the temperature of the reaction solution drops to 60°C. Filter quickly using a Buchner funnel preheated to 60°C. Wash three times with hot xylene at 60°C, twice with a 9:1 volume ratio ethanol / water mixture, and once with anhydrous ethanol. Then dry under vacuum at 80°C for 12 hours to obtain modified fumed silica.

[0034] The preparation method of rust-proof cable accessory insulating grease includes: weighing 100 parts of long-chain alkyl silicone oil, 16.5 parts of modified fumed silica, 1.5 parts of dimer fatty acid, and 0.5 parts of diphenylamine according to the proportion; adding the long-chain alkyl silicone oil and modified fumed silica together into a vacuum kneader, heating to 110℃, and stirring and kneading for 40 minutes; adding dimer fatty acid and diphenylamine, starting heating and kneading, keeping the temperature constant at 130℃, evacuating the vacuum after 85 minutes, continuing to knead for 30 minutes and stopping heating; stopping kneading when the temperature drops below 50℃, cooling to room temperature, and grinding three times on a three-roll mill to obtain rust-proof cable accessory insulating grease.

[0035] Example 2

[0036] This embodiment provides a rust-preventive cable accessory insulating grease, which, by weight, comprises 100 parts of long-chain alkyl silicone oil (viscosity 500 cSt), 8 parts of modified fumed silica, 0.01 parts of dimer fatty acid, and 0.1 parts of diphenylamine.

[0037] The modified fumed silica was prepared as follows: 20g of fumed silica (specific surface area 200±10 m² / g) was placed in a vacuum drying oven and dried at 120°C for 12 hours to remove physically adsorbed water. The dried fumed silica was then added to a ball mill jar with 200g of zirconia grinding balls (5mm in diameter) and milled at 300 rpm for 2 hours to obtain pretreated fumed silica. Nitrogen gas was introduced into a three-necked flask at a rate of 1L / min. After 30min, the pretreated 20g of fumed silica and 200mL of anhydrous xylene were added to the nitrogen-protected three-necked flask, and ultrasonic dispersion was initiated for 30min to form a uniform suspension. 1.85g of 1-[2-(triethoxysilyl)ethyl]benzotriazole and 1.15g of diphenyldimethoxysilane were weighed into a drying beaker and gently shaken to obtain a mixed silane solution. Measure 0.08 g of glacial acetic acid and add it to 0.42 g of anhydrous xylene. Mix well and transfer to a constant pressure dropping funnel. Add the mixed silane solution to a three-necked flask, heat to 60°C and stir at 300 rpm. Add diluted acetic acid dropwise at a rate of 0.5 mL / min. After the addition is complete, heat to 110°C, turn on the water separator, and stir under reflux for 24 hours. Add 0.08 g of zinc molybdate and continue the reaction for 1 hour. Nitrogen gas is continuously introduced at a rate of 1 L / min throughout the entire reaction. After the reaction is complete, allow it to cool naturally until the temperature of the reaction solution drops to 60°C. Filter quickly using a Buchner funnel preheated to 60°C. Wash three times with hot xylene at 60°C, twice with a 9:1 volume ratio ethanol / water mixture, and once with anhydrous ethanol. Then dry under vacuum at 80°C for 12 hours to obtain modified fumed silica.

[0038] The preparation method of rust-proof cable accessory insulating grease includes: weighing 100 parts of long-chain alkyl silicone oil, 8 parts of modified fumed silica, 0.01 parts of dimer fatty acid, and 0.1 parts of diphenylamine according to the proportion; adding the long-chain alkyl silicone oil and modified fumed silica together into a vacuum kneader, heating to 110℃, and stirring and kneading for 40 minutes; adding dimer fatty acid and diphenylamine, starting heating and kneading, keeping the temperature constant at 130℃, evacuating the vacuum after 85 minutes, continuing to knead for 30 minutes and then stopping heating; stopping kneading when the temperature drops below 50℃, cooling to room temperature, and grinding three times on a three-roll mill to obtain rust-proof cable accessory insulating grease.

[0039] Example 3

[0040] This embodiment provides a rust-preventive cable accessory insulating grease, which, by weight, comprises 100 parts of long-chain alkyl silicone oil (viscosity 500 cSt), 25 parts of modified fumed silica, 3 parts of dimer fatty acid, and 1 part of diphenylamine.

[0041] The modified fumed silica was prepared as follows: 20g of fumed silica (specific surface area 200±10 m² / g) was placed in a vacuum drying oven and dried at 120°C for 12 hours to remove physically adsorbed water. The dried fumed silica was then added to a ball mill jar with 200g of zirconia grinding balls (5mm in diameter) and milled at 300 rpm for 2 hours to obtain pretreated fumed silica. Nitrogen gas was introduced into a three-necked flask at a rate of 1L / min. After 30min, the pretreated 20g of fumed silica and 200mL of anhydrous xylene were added to the nitrogen-protected three-necked flask, and ultrasonic dispersion was initiated for 30min to form a uniform suspension. 4.14g of 1-[2-(triethoxysilyl)ethyl]benzotriazole and 0.86g of diphenyldimethoxysilane were weighed into a drying beaker and gently shaken to obtain a mixed silane solution. Measure 0.15 g of glacial acetic acid and add it to 0.75 g of anhydrous xylene. Mix well and transfer to a constant pressure dropping funnel. Add the mixed silane solution to a three-necked flask, heat to 60°C and stir at 300 rpm. Add diluted acetic acid dropwise at a rate of 0.5 mL / min. After the addition is complete, heat to 110°C, turn on the water separator, and stir and reflux for 24 hours. Add 0.08 g of zinc molybdate and continue the reaction for 1 hour. Nitrogen gas is continuously introduced at a rate of 1 L / min throughout the entire reaction. After the reaction is complete, allow it to cool naturally until the temperature of the reaction solution drops to 60°C. Filter quickly using a Buchner funnel preheated to 60°C. Wash three times with hot xylene at 60°C, twice with a 9:1 volume ratio ethanol / water mixture, and once with anhydrous ethanol. Then dry under vacuum at 80°C for 12 hours to obtain modified fumed silica.

[0042] The preparation method of rust-proof cable accessory insulating grease includes: weighing 100 parts of long-chain alkyl silicone oil, 25 parts of modified fumed silica, 3 parts of dimer fatty acid, and 1 part of diphenylamine according to the proportion; adding the long-chain alkyl silicone oil and modified fumed silica together into a vacuum kneader, heating to 110℃, and stirring and kneading for 40 minutes; adding dimer fatty acid and diphenylamine, starting heating and kneading, keeping the temperature constant at 130℃, evacuating the vacuum after 85 minutes, continuing to knead for 30 minutes and then stopping heating; stopping kneading when the temperature drops below 50℃, cooling to room temperature, and grinding three times on a three-roll mill to obtain rust-proof cable accessory insulating grease.

[0043] Comparative Example 1

[0044] This comparative example provides a cable accessory insulating grease, which, by weight, comprises 100 parts of long-chain alkyl silicone oil (viscosity 500 cSt), 16.5 parts of fumed silica (specific surface area 200±10 m² / g), 1.5 parts of dimer fatty acid, and 0.5 parts of diphenylamine.

[0045] The preparation method of cable accessory insulating grease includes: weighing 100 parts of long-chain alkyl silicone oil, 16.5 parts of fumed silica, 1.5 parts of dimer fatty acid, and 0.5 parts of diphenylamine according to the proportion; adding the long-chain alkyl silicone oil and fumed silica together into a vacuum kneader, heating to 110℃, and stirring and kneading for 40 minutes; adding dimer fatty acid and diphenylamine, starting heating and kneading, keeping the temperature constant at 130℃, evacuating the vacuum after 85 minutes, continuing to knead for 30 minutes and then stopping heating; stopping kneading when the temperature drops below 50℃, cooling to room temperature, and grinding three times on a three-roll mill to obtain cable accessory insulating grease.

[0046] Comparative Example 2

[0047] This comparative example provides an insulating lubricant for cable accessories and its preparation method, which is the same as in Example 1, except that the preparation method of the modified fumed silica is different. The preparation method of the modified fumed silica is as follows:

[0048] 20g of fumed silica (specific surface area 200±10 m² / g) was placed in a vacuum drying oven and dried at 120°C for 12 hours to remove physically adsorbed water. The dried fumed silica was then added to a ball mill jar with 200g of zirconia grinding balls (5mm in diameter) and ball-milled at 300 rpm for 2 hours to obtain pretreated fumed silica. Nitrogen gas was introduced into a three-necked flask at a rate of 1L / min. After 30 minutes, the pretreated 20g of fumed silica and 200mL of anhydrous xylene were added to the nitrogen-protected three-necked flask, and ultrasonic dispersion was initiated for 30 minutes to form a uniform suspension. 0.12g of glacial acetic acid was added to 0.6g of anhydrous xylene, mixed thoroughly, and transferred to a constant-pressure dropping funnel. Weigh 3.05 g of 1-[2-(triethoxysilyl)ethyl]benzotriazole into a three-necked flask, heat to 60°C and stir at 300 rpm. Add diluted acetic acid dropwise at a rate of 0.5 mL / min. After the addition is complete, heat to 110°C, turn on the water separator, and stir under reflux for 24 hours. Add 0.1 g of zinc molybdate and continue the reaction for 1 hour. Nitrogen gas is continuously introduced at a rate of 1 L / min throughout the entire reaction. After the reaction is complete, allow it to cool naturally until the temperature of the reaction solution drops to 60°C. Filter the solution quickly using a Buchner funnel preheated to 60°C. Wash three times with hot xylene at 60°C, twice with a 9:1 (v / v) ethanol / water mixture, and once with anhydrous ethanol. Then, dry under vacuum at 80°C for 12 hours to obtain modified fumed silica.

[0049] Comparative Example 3

[0050] This comparative example provides an insulating lubricant for cable accessories and its preparation method, which is the same as in Example 1, except that the preparation method of the modified fumed silica is different. The preparation method of the modified fumed silica is as follows:

[0051] 20g of fumed silica (specific surface area 200±10 m² / g) was placed in a vacuum drying oven and dried at 120°C for 12 hours to remove physically adsorbed water. The dried fumed silica was then added to a ball mill jar with 200g of zirconia grinding balls (5mm in diameter) and ball-milled at 300 rpm for 2 hours to obtain pretreated fumed silica. Nitrogen gas was introduced into a three-necked flask at a rate of 1L / min. After 30 minutes, the pretreated 20g of fumed silica and 200mL of anhydrous xylene were added to the nitrogen-protected three-necked flask, and ultrasonic dispersion was initiated for 30 minutes to form a uniform suspension. 0.12g of glacial acetic acid was added to 0.6g of anhydrous xylene, mixed thoroughly, and transferred to a constant-pressure dropping funnel. 0.95 g of diphenyldimethoxysilane was weighed and added to a three-necked flask. The temperature was raised to 60°C and stirred at 300 rpm. Diluted acetic acid was added dropwise at a rate of 0.5 mL / min. After the addition was complete, the temperature was raised to 110°C, the water separator was turned on, and the mixture was stirred and refluxed for 24 hours. 0.1 g of zinc molybdate was added and the reaction was continued for 1 hour. Nitrogen gas was continuously introduced at a rate of 1 L / min throughout the entire reaction. After the reaction was completed, the mixture was allowed to cool naturally until the temperature of the reaction solution dropped to 60°C. The solution was then rapidly filtered through a Buchner funnel preheated to 60°C. The solution was then washed three times with hot xylene at 60°C, twice with a 9:1 (v / v) ethanol / water mixture, and once with anhydrous ethanol. Finally, the solution was dried under vacuum at 80°C for 12 hours to obtain modified fumed silica.

[0052] Comparative Example 4

[0053] This comparative example provides an insulating lubricant for cable accessories and its preparation method, which is the same as in Example 1, except that the preparation method of the modified fumed silica is different. The preparation method of the modified fumed silica is as follows:

[0054] 20g of fumed silica (specific surface area 200±10 m² / g) was placed in a vacuum drying oven and dried at 120°C for 12 hours to remove physically adsorbed water. The dried fumed silica was then added to a ball mill jar with 200g of zirconia grinding balls (5mm in diameter) and milled at 300 rpm for 2 hours to obtain pretreated fumed silica. Nitrogen gas was introduced into a three-necked flask at a rate of 1L / min. After 30min, the pretreated 20g of fumed silica and 200mL of anhydrous xylene were added to the nitrogen-protected three-necked flask, and ultrasonic dispersion was started for 30min to form a uniform suspension. 3.05g of 1-[2-(triethoxysilyl)ethyl]benzotriazole and 0.95g of diphenyldimethoxysilane were weighed into a drying beaker and gently shaken to obtain a mixed silane solution. Measure 0.12 g of glacial acetic acid and add it to 0.6 g of anhydrous xylene. Mix well and transfer to a constant pressure dropping funnel. Add the mixed silane solution to a three-necked flask, heat to 60°C and stir at 300 rpm. Add diluted acetic acid dropwise at a rate of 0.5 mL / min. After the addition is complete, heat to 110°C, turn on the water separator, and stir under reflux for 24 hours. Nitrogen gas is continuously introduced at a rate of 1 L / min throughout the reaction. After the reaction is complete, allow it to cool naturally until the temperature of the reaction solution drops to 60°C. Filter quickly using a Buchner funnel preheated to 60°C. Wash three times with hot xylene at 60°C, twice with a 9:1 volume ratio ethanol / water mixture, and once with anhydrous ethanol. Then dry under vacuum at 80°C for 12 hours to obtain modified fumed silica.

[0055] Comparative Example 5

[0056] This comparative example provides a cable accessory insulating grease, which, by weight, comprises 100 parts of long-chain alkyl silicone oil (viscosity 500 cSt), 16.5 parts of fumed silica (specific surface area 200±10 m² / g), 1.5 parts of dimer fatty acid, 0.5 parts of diphenylamine, 3.3 parts of silane mixed solution, and 0.08 parts of zinc molybdate.

[0057] The preparation method of cable accessory insulating grease includes: preparing a silane mixed solution according to the mass ratio of diphenyldimethoxysilane and 1-[2-(triethoxysilyl)ethyl]benzotriazole of 1:3.2; weighing 100 parts of long-chain alkyl silicone oil, 16.5 parts of fumed silica, 1.5 parts of dimer fatty acid, 0.5 parts of diphenylamine, 3.3 parts of silane mixed solution, and 0.08 parts of zinc molybdate according to the proportion; adding the long-chain alkyl silicone oil, fumed silica, and silane mixed solution together into a vacuum kneader, heating to 110℃, and stirring and kneading for 40 min; adding dimer fatty acid, diphenylamine, and zinc molybdate, starting heating and kneading, keeping the temperature constant at 130℃, evacuating vacuum after 85 min, continuing kneading for 30 min, stopping heating, stopping kneading when the temperature drops below 50℃, cooling to room temperature, and grinding three times on a three-roll mill to obtain the cable accessory insulating grease.

[0058] The physicochemical properties of the cable accessory insulating greases obtained in each embodiment and comparative example are shown in the table below:

[0059] Breakdown voltage (2.5mm spacing, flat plate), KV / mm Volume resistivity (25℃), Ω·cm Copper strip corrosion test (100℃, 24h) Rust area from salt spray test (pH 3.2, 35℃, 48h) Example 1 35.7 <![CDATA[4.30×10 15 ]]> 1a 0.25% Example 2 37.3 <![CDATA[5.26×10 15 ]]> 1a 0.38% Example 3 32.8 <![CDATA[8.64×10 14 ]]> 1a 0.27% Comparative Example 1 22.5 <![CDATA[2.13×10 14 ]]> 1b 1.32% Comparative Example 2 30.6 <![CDATA[4.89×10 14 ]]> 1a 0.29% Comparative Example 3 35.1 <![CDATA[3.85×10 15 ]]> 1a 0.85% Comparative Example 4 33.9 <![CDATA[3.56×10 15 ]]> 1a 0.33% Comparative Example 5 25.6 <![CDATA[3.58×10 14 ]]> 1b 0.88% Test methods GB / T507-2002 GB / T5654-2007 GB / T7326-1987 GB / T 10125-2021

[0060] As shown in the table above, the cable accessory insulating grease prepared by the technical solution of the present invention achieves a dual protection mechanism of metal passivation and electron migration barrier through the precise construction of a benzotriazole-diphenylsilane composite functional layer on the surface of modified fumed silica, thereby comprehensively improving the anti-rust and insulation performance of the cable accessory insulating grease.

[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An anti-rust cable accessory insulation lubricating grease, characterized by: By weight parts, including the following components: 100 parts of base oil, 8-25 parts of modified fumed silica, 0.01-3 parts of extreme pressure anti-wear agent, 0.1-1 parts of antioxidant; The modified fumed silica is prepared by one-step silane crosslinking process, and the preparation method comprises the following steps: under the protection of nitrogen, the fumed silica is dispersed in anhydrous xylene, a mixed silane solution is added, stirring is carried out to heat to 58-62℃, then acetic acid diluent is added dropwise, then heating is carried out to 105-115℃, stirring is carried out to reflux for 23-25h, zinc molybdate is added to continue to react for 0.9-1.1h, filtration, washing and drying are carried out to obtain the modified fumed silica; The mass ratio of the fumed silica to the mixed silane solution is 1:0.15-0.25; The mixed silane solution is a mixed solution of diphenyldimethoxysilane and 1-[2-(triethoxysilyl)ethyl]benzotriazole, and the mass ratio of diphenyldimethoxysilane to 1-[2-(triethoxysilyl)ethyl]benzotriazole is 1:1.6-4.

8.

2. A rust preventive cable accessory insulating lubricating grease as set forth in claim 1, characterized in that: The mass ratio of the acetic acid diluent to the fumed silica is 0.025-0.045:1, the acetic acid diluent is a mixed solution of acetic acid and anhydrous xylene, and the mass ratio of acetic acid to anhydrous xylene is 1:4.9-5.1; the dropping speed of the acetic acid diluent is 0.45-0.55mL / min.

3. A rust preventive cable accessory insulating lubricating grease as set forth in claim 1, characterized by: The addition amount of the zinc molybdate is 0.4-0.6wt% of the fumed silica.

4. A rust preventive cable accessory insulating lubricating grease as set forth in claim 1, characterized by: The filtration is hot filtration, and the hot filtration temperature is 55-62℃.

5. A rust preventive cable accessory insulating lubricating grease as set forth in claim 1, characterized by: The base oil is long-chain alkyl silicone oil, and the long-chain alkyl silicone oil has a kinematic viscosity of 200-1000cSt at 25℃.

6. A rust preventive cable accessory insulating lubricating grease as set forth in claim 1, characterized by: The extreme pressure anti-wear agent is one or more of dimer fatty acid, cresyl phosphate and triphenyl phosphorothioate; and the antioxidant is one or more of diphenylamine, antioxidant 1076, antioxidant 1010 and antioxidant 264.

7. A process for the preparation of an anti-rust cable accessory insulation grease, characterized in that: The preparation method is used for preparing the rust-proof cable accessory insulation lubricating grease according to any one of claims 1-6, and the preparation method comprises the following steps: S1, proportionally weighing base oil, modified fumed silica, extreme pressure anti-wear agent and antioxidant; S2, heating and warming the base oil and the modified fumed silica to 100-110℃, and stirring and kneading uniformly; S3, adding the extreme pressure anti-wear agent and the antioxidant, starting warming and kneading, keeping the temperature at 128-132℃, vacuumizing after 80-90min, stopping heating after stirring and kneading uniformly, stopping kneading when the temperature drops below 50℃, and grinding on a three-roll mill for three times after cooling to room temperature to obtain the rust-proof cable accessory insulation lubricating grease.