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CN-121975330-A - High-stability silicon rubber composite material, preparation method thereof and cable

CN121975330ACN 121975330 ACN121975330 ACN 121975330ACN-121975330-A

Abstract

The invention discloses a high-stability silicone rubber composite material, a preparation method thereof and a cable, and belongs to the technical field of material preparation. According to the invention, a sol-gel method is adopted to prepare ternary composite filler (TiO 2 @Fe-MOFs@F) with nano TiO 2 as a core and in-situ grown Fe-MOFs as an intermediate shell layer and a covalent grafted hydrophobic functional layer, so that stable application of the Fe-MOFs in a cooling liquid environment is realized for the first time, and the thermal oxidative aging performance, liquid corrosion resistance, electrical insulation reliability and flame retardance of the material are synergistically improved, thereby meeting the extreme performance requirements of a 800V high-voltage platform new energy automobile on the cable material. The obtained silicon rubber composite material shows the performance retention rate and the reliability far exceeding the prior art in the composite or sequential stress tests of long-term thermal oxidation aging, cooling liquid soaking, wet thermal aging, cold and hot impact and the like, and meets the use requirements of the high-voltage cable of the new energy automobile.

Inventors

  • DENG JINYU
  • WANG CHUANFU
  • Gong Yuanliang
  • CHEN LINGXIANG
  • WU XIAO
  • XIE TINGYU
  • ZHOU JIANBO

Assignees

  • 贵阳中安科技集团有限公司

Dates

Publication Date
20260505
Application Date
20260212

Claims (10)

  1. 1. The high-stability silicone rubber composite material is characterized by comprising, by mass, 100 parts of methyl vinyl silicone rubber, 10-30 parts of fumed silica, 2-8 parts of hydroxyl silicone oil, 0.5-3 parts of a silane coupling agent, 3-15 parts of a ternary composite filler, 0.5-2 parts of a vulcanizing agent, 0.1-1 part of an antioxidant, 0.01-0.1 part of a platinum catalyst and 0.5-3 parts of a phosphorus-nitrogen composite flame retardant; The preparation method of the ternary composite filler comprises the following steps: A1, preparing nano TiO 2 sol, namely mixing acid liquor and titanium precursor solution to ensure that the molar ratio of hydrogen ions to titanium ions in a reaction system is 0.1-0.2:0.5-1.5, stirring and reacting for 6-12h at room temperature, standing and aging for 8-24h, and finally carrying out hydrothermal reaction for 6-12h at 120-200 ℃ to obtain nano TiO 2 sol; A2, surface amino modification, namely concentrating nano TiO 2 sol, dispersing in an organic solvent, adding a silane coupling agent into TiO 2 suspension, wherein the addition amount is 2-6% of the mass of TiO 2 , and then reacting for 1-2 hours at 70-80 ℃ to obtain an amino TiO 2 dispersion; A3, in-situ growth of Fe-MOFs shell layers, namely mixing ferric salt and terephthalic acid in a molar ratio of 1.5-2.5:0.5-1.5, then adding the mixture into an amination TiO 2 dispersion liquid, reacting for 20-36 hours at 110-130 ℃, centrifuging, washing, and drying the washed matter to constant weight at 80-90 ℃ to obtain Ti 2 @Fe-MOFs powder, wherein the dosage of the amination TiO 2 dispersion liquid is 1% -10% of the total volume of the ferric salt and the terephthalic acid; A4, constructing a hydrophobic functional layer, namely dispersing TiO 2 @Fe-MOFs powder in an organic solvent, then adding 1-5 wt% of perfluorooctyl triethoxysilane, reacting for 4-8 hours at 70-85 ℃, centrifuging, washing, and drying the washed product at 80-100 ℃ for 10-12 hours to obtain the ternary composite filler.
  2. 2. The high-stability silicone rubber composite material according to claim 1, wherein the raw materials comprise, by mass, 100 parts of methyl vinyl silicone rubber, 20 parts of gas-phase white carbon black, 5 parts of hydroxyl silicone oil, 2 parts of a silane coupling agent, 10 parts of a ternary composite filler, 1 part of a vulcanizing agent, 0.5 part of an antioxidant, 0.05 part of a platinum catalyst and 1.5 parts of a phosphorus-nitrogen composite flame retardant.
  3. 3. The high stability silicone rubber composite of claim 1, wherein the vulcanizing agent is one or more of 2, 5-dimethyl-2, 5-di-t-butylperoxy hexane, dicumyl peroxide and 1, 1-bis (t-butylperoxy) -3, 5-trimethylcyclohexane, and the antioxidant is one or more of 1010, 1076, 330 and 168 antioxidants.
  4. 4. The high stability silicone rubber composite of claim 1, wherein the acid solution is dilute nitric acid, dilute hydrochloric acid, or dilute sulfuric acid.
  5. 5. The high stability silicone rubber composite of claim 1, wherein the titanium precursor solution is one or more of tetrabutyl titanate, tetraisopropyl titanate, and tetraethyl titanate.
  6. 6. The high stability silicone rubber composite according to claim 1, wherein the organic solvent is absolute ethanol, methanol, isopropanol or n-butanol.
  7. 7. The high stability silicone rubber composite according to claim 1, wherein the silane coupling agent is KH-550, KH-540 or KH-792.
  8. 8. The high stability silicone rubber composite of claim 1, wherein the iron salt is one or more of ferric chloride, ferric nitrate, and ferric sulfate.
  9. 9. The method for preparing a high-stability silicone rubber composite material according to any one of claims 1 to 8, comprising the steps of: S1, firstly, using a double-roller open mill to roll methyl vinyl silicone rubber Bao Tongbao, then sequentially adding fumed silica, hydroxyl silicone oil, a silane coupling agent and ternary composite filler, and repeatedly cutting and turning at a roll temperature of 40-60 ℃ for 30-45min; S2, cooling the lower piece of the sizing material to room temperature, then adding the rest raw materials, and discharging the piece after 2-5 times of thin ventilation to obtain a rubber compound; S3, filling the rubber compound into a cable extruder preheated to 110-130 ℃, vulcanizing for 10-30min at 170-180 ℃ and 10-15MPa, heating to 190-210 ℃ and vulcanizing for 3-5h at two stages to obtain the silicone rubber composite material.
  10. 10. The silicone rubber composite cable is characterized by sequentially comprising a conductor layer (1), an insulating layer (2), a shielding layer (3) and a sheath layer (4) from inside to outside, wherein the raw materials used for the insulating layer (2) are the silicone rubber composite material according to any one of claims 1-8.

Description

High-stability silicon rubber composite material, preparation method thereof and cable Technical Field The invention belongs to the technical field of material preparation, and particularly relates to a high-stability silicone rubber composite material, a preparation method thereof and a cable. Background As new energy automobiles are developed to high voltage platforms (e.g., 800V), high energy density batteries, and ultra-high power electric drive systems, the working environment of their internal wiring systems is becoming extremely harsh, and cable insulation materials are required to withstand local high temperatures up to 150-200 ℃ for long periods of time, withstand direct voltage stresses above 1000V, and may be exposed to glycol-based coolant environments due to leakage from thermal management systems. Under the long-term action of the composite stress (heat, oxygen, electricity and chemical medium), the traditional cross-linked polyethylene (XLPE), ethylene Propylene Rubber (EPR) and common Silicon Rubber (SR) are easy to cause accelerated degradation of insulation and mechanical properties, and after cooling liquid is permeated, the swelling, plasticization and rapid decline of dielectric strength of the material are easy to cause, and electric leakage or short circuit can be possibly caused, so that potential safety hazards are caused. Room temperature vulcanized silicone Rubber (RTV) is considered as one of ideal candidate materials for high voltage cable insulation due to its excellent electrical insulation, flexibility and broad temperature range stability. However, the organic side chains and the silicon-oxygen main chains of the silicone rubber undergo thermooxidative aging in a high-temperature aerobic environment, resulting in breakage of molecular chains and destruction of a crosslinked network, which are manifested in hardening and embrittlement of the material, degradation of mechanical properties and insulation failure. Although some studies have attempted to improve the properties of silicone rubber by adding inorganic fillers or flame retardants, these methods tend to sacrifice flexibility, processability, or electrical properties, have limited barrier effects against permeation of polar small molecules such as cooling fluids, and fail to achieve long-term stability under "thermo-wet-liquid-electric" multi-field coupling. Therefore, developing a silicon rubber composite material which can cooperatively solve the problems of long-term thermal oxidative aging, coolant erosion resistance, high volume resistivity and high reliability becomes an urgent need for the development of new energy automobiles. Disclosure of Invention The invention aims to solve the technical problems of poor working performance and insufficient coolant erosion resistance of the traditional silicone rubber cable material under complex and severe working conditions (long-term high-temperature or thermal oxidation aging environment). In order to achieve the aim, the invention adopts the technical scheme that the high-stability silicone rubber composite material is provided, and comprises, by mass, 100 parts of methyl vinyl silicone rubber, 10-30 parts of fumed silica, 2-8 parts of hydroxyl silicone oil, 0.5-3 parts of a silane coupling agent, 3-15 parts of a ternary composite filler (TiO 2 @Fe-MOFs@F), 0.5-2 parts of a vulcanizing agent, 0.1-1 part of an antioxidant, 0.01-0.1 part of a platinum catalyst and 0.5-3 parts of a phosphorus-nitrogen composite flame retardant; The preparation method of the ternary composite filler (TiO 2 @Fe-MOFs@F) comprises the following steps: A1, preparing nano TiO 2 sol, namely mixing acid liquor and titanium precursor solution under the protection of nitrogen, enabling the molar ratio of hydrogen ions to titanium ions in a reaction system to be 0.1-0.2:0.5-1.5, stirring at room temperature for reaction for 6-12h, standing and aging for 8-24h, and finally carrying out hydrothermal reaction at 120-200 ℃ for 6-12h to obtain nano TiO 2 sol; A2, surface amino modification, namely concentrating nano TiO 2 sol, dispersing in an organic solvent, adding a silane coupling agent into TiO 2 suspension, wherein the addition amount is 2-6% of the mass of TiO 2, and then placing the mixture at 70-80 ℃ for reaction for 1-2 hours to enable the surfaces of TiO 2 particles to be grafted with amino functional groups, so as to obtain an amino TiO 2 dispersion; A3, growing Fe-MOFs shell in situ, namely mixing ferric salt and terephthalic acid in a molar ratio of 1.5-2.5:0.5-1.5, then adding the mixture into an aminated TiO 2 dispersion liquid, reacting for 20-36 hours at 110-130 ℃, wherein Fe 3+ and terephthalic acid take TiO 2 nano particles with amino grafted on the surfaces as heterogeneous nucleation points in the reaction process, growing in situ on the surfaces to form uniform Fe-MOFs (MIL-101 (Fe) shell layers, centrifuging, washing, and drying the washed matter at 80-90 ℃ to constant weight to o