A multifunctional flame-retardant high-dielectric liquid for vehicle adaptive structures and its preparation method

Abstract

This invention discloses a multifunctional flame-retardant high-dielectric liquid for vehicle adaptive structures and its preparation method. The invention relates to the field of functional materials technology and comprises the following components by mass percentage: perfluoropolyether base oil: 70% to 90%; surface-modified ferroelectric ceramic filler: 5% to 20%, wherein the average particle size of the ferroelectric ceramic filler is 10 nanometers to 10 micrometers, and it is surface-treated with a silane coupling agent or a titanate coupling agent; viscosity modifier: 2% to 8%, wherein the viscosity modifier is selected from at least one of fluorinated polyolefins, fluorinated silicone oils, or hydrogenated styrene-isoprene copolymers. This liquid uses perfluoropolyether, which has excellent chemical inertness and high thermal stability, as the base oil. By adding surface-modified high-dielectric-constant ferroelectric ceramic filler, the dielectric constant can be improved while maintaining high insulation. The introduction of a specific viscosity modifier enables the liquid to have relatively stable rheological properties over a wide temperature range, meeting damping adjustment requirements.

Description

Technical Field

[0001] This invention relates to the field of functional materials technology, specifically to a multifunctional flame-retardant high-dielectric liquid for vehicle adaptive structures and its preparation method. Background Technology

[0002] In the fields of modern new energy vehicles, aerospace, and high-end equipment, the demand for functional fluids that can simultaneously meet multiple physical and chemical performance requirements is becoming increasingly urgent. These fluids are often referred to as "dielectric fluids" or "engineering functional fluids," and their core function is to perform one or more functions such as insulation, heat transfer, damping, or protection under specific operating conditions. For example, transformer oil used for insulation and cooling in power equipment, and hydraulic oil used for power transmission and lubrication in hydraulic systems, both fall into this category. With technological advancements, especially the increasing integration and multi-functionality of intelligent vehicles, more complex and demanding performance requirements have emerged for dielectric materials. For instance, fluid units used for active safety or structural deformation regulation require their working media to not only possess the electrical insulation properties of traditional insulating oils but may also be required to have excellent flame retardancy, efficient thermal management capabilities, controllable damping characteristics, and good long-term compatibility with sensitive components such as batteries.

[0003] However, existing functional liquids often focus on meeting a single core performance requirement, making it difficult to achieve a balance across multiple demanding specifications. For example, while traditional mineral insulating oils or silicone oils possess good electrical insulation properties, they have limited flash points, insufficient flame retardancy, and typically low specific heat capacity, resulting in mediocre thermal management capabilities. Phosphate ester liquids, specifically designed for flame retardancy, may pose a risk of side reactions with battery materials, affecting the stability of the electrochemical system. Perfluoropolyether liquids, with their excellent chemical inertness and thermal stability, have limitations in terms of dielectric constant adjustment and viscosity-temperature characteristic optimization when used in their pure form.

[0004] To address this issue, a multifunctional flame-retardant high-dielectric liquid for vehicle adaptive structures and its preparation method were designed to solve the aforementioned technical problems. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a multifunctional flame-retardant high-dielectric liquid for vehicle adaptive structures and its preparation method, thus solving the technical problems mentioned in the background section.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a multifunctional flame-retardant high-dielectric liquid for vehicle adaptive structures, comprising components in the following mass percentages: a) Perfluoropolyether base oil: 70% to 90%; b) Surface-modified ferroelectric ceramic filler: 5% to 20%, wherein the average particle size of the ferroelectric ceramic filler is 10 nanometers to 10 micrometers, and the filler is surface-treated with silane coupling agent or titanate coupling agent. c) Viscosity modifier: 2% to 8%, wherein the viscosity modifier is selected from at least one of fluorinated polyolefins, fluorinated silicone oils or hydrogenated styrene-isoprene copolymers; d) Stabilizer complex system: 0.5% to 2%, wherein the stabilizer complex system comprises phenolic antioxidants, amine antioxidants and metal passivators; e) Corrosion inhibitor: 0.1% to 1%; The liquid has a dielectric strength of not less than 40 kV / mm at 25°C and a flash point of not less than 300°C or is non-flammable.

[0007] Preferably, the molecular structure of the perfluoropolyether base oil is F-(CF(CF3)-CF2-O)n-CF2-CF3, and its kinematic viscosity at 40°C is 30 cSt to 100 cSt.

[0008] Preferably, the ferroelectric ceramic filler is selected from at least one of barium titanate, barium strontium titanate, or lead magnesium niobate-lead titanate.

[0009] Preferably, the phenolic antioxidant is 2,6-di-tert-butyl-p-cresol, the amine antioxidant is alkylated diphenylamine, and the metal passivator is a benzotriazole derivative.

[0010] Preferably, it further comprises phase change material microcapsules dispersed therein, wherein the amount of phase change material microcapsules added is 0% to 15% of the total mass of the multifunctional flame-retardant high dielectric liquid.

[0011] Preferably, the phase change material microcapsules have a core of paraffin, fatty acid or hydrated salt and a wall material of melamine resin or polyurea, with an average particle size of 1 micrometer to 100 micrometers.

[0012] A method for preparing a multifunctional flame-retardant high-dielectric liquid includes the following steps: S1: The ferroelectric ceramic filler is vacuum dried at 80-120°C, then dispersed in anhydrous ethanol, a silane coupling agent is added, and the mixture is stirred at 60-80°C for 2-4 hours. After the reaction is completed, the filler is separated, washed, and dried to obtain the surface-modified ferroelectric ceramic filler. S2: Under an inert atmosphere, heat the perfluoropolyether base oil to 60-80°C; S3: Under stirring and high-speed shear dispersion conditions, the surface-modified ferroelectric ceramic filler obtained in step S1, the viscosity modifier, the stabilizer composite system and the corrosion inhibitor obtained in step S2 are added to the base oil in step S2 in sequence, and the components are uniformly dispersed or dissolved. S4: Vacuum degassing and precision filtration are performed on the mixture obtained in step S3.

[0013] Preferably, in step S3, when the multifunctional flame-retardant high-dielectric liquid contains phase change material microcapsules, after adding the corrosion inhibitor and mixing evenly, the phase change material microcapsules are added at a stirring speed of less than 500 rpm and mixed evenly. Beneficial effects

[0014] This invention provides a multifunctional flame-retardant high-dielectric liquid for vehicle adaptive structures and its preparation method. The liquid uses a chemically inert and thermally stable perfluoropolyether as a base oil. By adding surface-modified high-dielectric-constant ferroelectric ceramic fillers, the dielectric constant can be increased while maintaining high insulation. The introduction of a specific viscosity modifier enables the liquid to exhibit relatively stable rheological properties over a wide temperature range, meeting damping adjustment requirements. The composite system of stabilizers and corrosion inhibitors helps ensure the liquid's performance stability during long-term use and its compatibility with common engineering materials such as metals and elastomers. Overall, this liquid integrates multiple functions including insulation protection, flame retardant safety, thermal management, and damping adjustment, meeting the comprehensive requirements of media materials in vehicle adaptive structures and providing a reliable material basis for the design of intelligent vehicle-related systems. Attached Figure Description

[0015] Figure 1 This is a flowchart illustrating the multifunctional flame-retardant high-dielectric liquid for vehicle adaptive structures and its preparation method as described in this invention. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] Please see Figure 1 This invention provides a technical solution: a multifunctional flame-retardant high-dielectric liquid for vehicle adaptive structures, comprising the following components by mass percentage: a) 70% to 90% perfluoropolyether base oil; b) 5% to 20% of surface-modified ferroelectric ceramic filler, wherein the average particle size of the ferroelectric ceramic filler is 10 nanometers to 10 micrometers and is surface-treated with silane coupling agent or titanate coupling agent. c) Viscosity modifier: 2% to 8%, wherein the viscosity modifier is selected from at least one of fluorinated polyolefins, fluorinated silicone oils or hydrogenated styrene-isoprene copolymers; d) Stabilizer complex system: 0.5% to 2%, wherein the stabilizer complex system comprises phenolic antioxidants, amine antioxidants and metal passivators; e) Corrosion inhibitor: 0.1% to 1%; The liquid has a dielectric strength of not less than 40 kV / mm at 25°C and a flash point of not less than 300°C or is non-flammable.

[0018] In this embodiment, the molecular structure of the perfluoropolyether base oil is F-(CF(CF3)-CF2-O)n-CF2-CF3, and its kinematic viscosity at 40°C is 30 cSt to 100 cSt.

[0019] In this embodiment, the ferroelectric ceramic filler is further selected from at least one of barium titanate, barium strontium titanate, or lead magnesium niobate-lead titanate.

[0020] In this embodiment, the phenolic antioxidant is 2,6-di-tert-butyl-p-cresol, the amine antioxidant is alkylated diphenylamine, and the metal passivating agent is a benzotriazole derivative.

[0021] This embodiment is further configured to include phase change material microcapsules dispersed therein, wherein the amount of phase change material microcapsules added is 0% to 15% of the total mass of the multifunctional flame-retardant high dielectric liquid.

[0022] In this embodiment, the phase change material microcapsules are configured such that the core is paraffin, fatty acid or hydrated salt, and the wall material is melamine resin or polyurea, with an average particle size of 1 micrometer to 100 micrometers.

[0023] A method for preparing a multifunctional flame-retardant high-dielectric liquid includes the following steps: S1: The ferroelectric ceramic filler is vacuum dried at 80-120°C, then dispersed in anhydrous ethanol, a silane coupling agent is added, and the mixture is stirred at 60-80°C for 2-4 hours. After the reaction is completed, the filler is separated, washed, and dried to obtain the surface-modified ferroelectric ceramic filler. S2: Under an inert atmosphere, heat the perfluoropolyether base oil to 60-80°C; S3: Under stirring and high-speed shear dispersion conditions, the surface-modified ferroelectric ceramic filler obtained in step S1, the viscosity modifier, the stabilizer composite system and the corrosion inhibitor obtained in step S2 are added to the base oil in step S2 in sequence, and the components are uniformly dispersed or dissolved. S4: Vacuum degassing and precision filtration are performed on the mixture obtained in step S3.

[0024] In this embodiment, it is further configured that, in step S3, when the multifunctional flame-retardant high dielectric liquid contains phase change material microcapsules, after adding the corrosion inhibitor and mixing evenly, the phase change material microcapsules are added at a stirring speed of less than 500 rpm and mixed evenly.

[0025] Its detailed connection method is a well-known technology in this field. The following mainly introduces the working principle and process, and the specific work is as follows.

[0026] Example 1: High-damping insulating liquid for vehicle body adaptive pneumatic capsule unit Formulated according to the following mass percentages: 85% perfluoropolyether base oil (kinematic viscosity at 40°C approximately 46 cSt), 10% surface-modified barium titanate nanoparticles with an average particle size of approximately 100 nm (treated with KH-550 silane coupling agent), 3.5% polytetrafluoroethylene microparticles (as thickener), 1.2% composite antioxidant composed of 2,6-di-tert-butyl-p-cresol and alkylated diphenylamine, and 0.3% benzotriazole derivative (as corrosion inhibitor).

[0027] The preparation process is as follows: First, barium titanate nanoparticles were vacuum dried at 100°C for 2 hours, then dispersed in anhydrous ethanol. 2% (by mass) of KH-550 coupling agent was added, and the mixture was stirred at 70°C for 3 hours. After the reaction, the mixture was centrifuged, washed twice with ethanol, and then vacuum dried at 80°C for 4 hours to obtain surface-modified barium titanate filler. Under nitrogen protection, perfluoropolyether base oil was added to the reactor, heated to 70°C, and stirred. While maintaining stirring, a high-speed shear disperser (approximately 3000 rpm) was turned on, and the above-mentioned surface-modified barium titanate filler was slowly added, continuously dispersed at high speed for 1.5 hours. Then, polytetrafluoroethylene microparticles, composite antioxidants, and corrosion inhibitors were added sequentially, with stirring continued for 30 minutes after each component addition to ensure complete dispersion or dissolution. The resulting mixture was degassed at 70°C and a vacuum of -0.098 MPa for 3 hours, and then filtered through a 5-micron precision filter to obtain the target liquid.

[0028] The liquid was tested and found to have a dielectric strength of approximately 45 kV / mm at 25°C (measured according to ASTM D877), and a relative permittivity of approximately 4.8 at 1 kHz. Its kinematic viscosity is approximately 2800 cSt at -40°C, approximately 52 cSt at 40°C, and approximately 18 cSt at 100°C (measured according to ASTM D445). Tested according to ASTM D92, its flash point is above 320°C, indicating non-flammability. A 1000-hour compatibility test at 150°C with EPDM rubber seals showed a rubber volume change of less than 5%. This liquid is suitable for filling pneumatic capsule units in adaptive vehicle body structures, providing controllable damping while ensuring reliable insulation from high-voltage electrical components.

[0029] Example 2: Flame-retardant high-dielectric liquid for immersion cooling and safety protection of power battery packs The mixture is formulated according to the following mass percentages: 78% perfluoropolyether base oil (kinematic viscosity at 40°C is approximately 30 cSt), 15% surface-modified barium strontium titanate micropowder (treated with KH-560 silane coupling agent) with an average particle size of approximately 5 μm, 4% hydrogenated styrene-isoprene copolymer (as a viscosity index improver), 2% composite stabilizer composed of 2,6-di-tert-butyl-p-cresol, alkylated diphenylamine and benzotriazole derivatives, and 10% paraffin phase change microcapsules (phase change temperature approximately 35°C, wall material is melamine resin, average particle size approximately 20 μm) by addition.

[0030] The preparation process was carried out according to Example 1, with the following differences: KH-560 coupling agent was used in the surface modification step; after the basic mixing and dispersion steps were completed, the system temperature was lowered to below 40°C, and then paraffin phase change microcapsules were slowly added at a stirring speed of less than 300 rpm, and gently stirred for 1 hour to ensure uniform dispersion. Finally, the liquid was obtained after degassing and filtration.

[0031] The liquid's dielectric strength at 25°C was tested to be approximately 48 kV / mm. Its specific heat capacity (measured by differential scanning calorimetry) was approximately 1.8 J / g·K. A 28-day immersion test was conducted at 60°C on typical components of commercial lithium-ion batteries (including NCM811 positive electrode, graphite negative electrode, polyethylene separator, and aluminum and copper foil). After the test, no significant corrosion, dissolution, or morphological changes were observed in the battery materials under visual and microscopic examination. Half-cell assembly tests were performed on the immersed electrode materials, and the changes in open-circuit voltage, AC internal resistance, and charge / discharge capacity compared to the unimmersed control sample were all within the normal testing error range. This liquid is suitable as an immersion cooling and protection medium for power battery packs, providing direct and efficient heat dissipation while offering a safety barrier for the battery system due to its high dielectric strength and inherent non-flammability.

[0032] It should be noted that in this paper, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

Claims

1. A multifunctional flame-retardant high-dielectric liquid for vehicle adaptive structures, Includes, characterized in that, It consists of the following components by mass percentage: a) Perfluoropolyether base oil: 70% to 90%; b) Surface-modified ferroelectric ceramic filler: 5% to 20%, wherein the average particle size of the ferroelectric ceramic filler is 10 nanometers to 10 micrometers, and the filler is surface-treated with silane coupling agent or titanate coupling agent. c) Viscosity modifier: 2% to 8%, wherein the viscosity modifier is selected from at least one of fluorinated polyolefins, fluorinated silicone oils or hydrogenated styrene-isoprene copolymers; d) Stabilizer complex system: 0.5% to 2%, wherein the stabilizer complex system comprises phenolic antioxidants, amine antioxidants and metal passivators; e) Corrosion inhibitor: 0.1% to 1%; The liquid has a dielectric strength of not less than 40 kV / mm at 25°C and a flash point of not less than 300°C or is non-flammable.

2. The multifunctional flame-retardant high-dielectric liquid for vehicle adaptive structures according to claim 2, characterized in that, The general molecular structure of the perfluoropolyether base oil is F-(CF(CF3)-CF2-O)n-CF2-CF3, and its kinematic viscosity at 40°C is 30 cSt to 100 cSt.

3. The multifunctional flame-retardant high-dielectric liquid for vehicle adaptive structures according to claim 1, characterized in that... The ferroelectric ceramic filler is selected from at least one of barium titanate, barium strontium titanate, or lead magnesium niobate-lead titanate.

4. The multifunctional flame-retardant high-dielectric liquid for vehicle adaptive structures according to claim 1, characterized in that... The phenolic antioxidant is 2,6-di-tert-butyl-p-cresol, the amine antioxidant is alkylated diphenylamine, and the metal passivating agent is a benzotriazole derivative.

5. A multifunctional flame-retardant high-dielectric liquid for vehicle adaptive structures according to claim 1, characterized in that... It also contains phase change material microcapsules dispersed therein, wherein the amount of phase change material microcapsules added is 0% to 15% of the total mass of the multifunctional flame-retardant high dielectric liquid.

6. A multifunctional flame-retardant high-dielectric liquid for vehicle adaptive structures according to claim 5, characterized in that... The phase change material microcapsules have paraffin, fatty acid or hydrated salt as the core and melamine resin or polyurea as the wall material, with an average particle size of 1 micrometer to 100 micrometers.

7. A method for preparing the multifunctional flame-retardant high-dielectric liquid as described in any one of claims 1 to 6, characterized in that, Includes the following steps: S1: The ferroelectric ceramic filler is vacuum dried at 80-120°C, then dispersed in anhydrous ethanol, a silane coupling agent is added, and the mixture is stirred at 60-80°C for 2-4 hours. After the reaction is completed, the filler is separated, washed, and dried to obtain the surface-modified ferroelectric ceramic filler. S2: Under an inert atmosphere, heat the perfluoropolyether base oil to 60-80°C; S3: Under stirring and high-speed shear dispersion conditions, the surface-modified ferroelectric ceramic filler obtained in step S1, the viscosity modifier, the stabilizer composite system and the corrosion inhibitor obtained in step S2 are added to the base oil in step S2 in sequence, and the components are uniformly dispersed or dissolved. S4: Vacuum degassing and precision filtration are performed on the mixture obtained in step S3.

8. The method for preparing a multifunctional flame-retardant high-dielectric liquid for vehicle adaptive structures according to claim 7, characterized in that... In step S3, when the multifunctional flame-retardant high dielectric liquid contains phase change material microcapsules, after adding the corrosion inhibitor and mixing evenly, the phase change material microcapsules are added at a stirring speed of less than 500 rpm and mixed evenly.

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