Organic sealing protective composite material for power equipment and preparation method thereof

Abstract

This invention provides an organic sealing and protective composite material for power equipment and its preparation method, belonging to the field of polymer material preparation technology. The organic sealing and protective composite material for power equipment provided by this invention includes an electric field conducting layer and an electroactive sealing layer disposed on the surface of the electric field conducting layer. This invention converts the electric field during power equipment operation into a driving force for actively compensating for interfacial thermal mismatch. The electric field is introduced into the electroactive sealing layer through the electric field conducting layer, causing it to undergo electrostrictive deformation, thereby filling the interfacial micro-gap caused by temperature changes in real time. This fundamentally solves the problem of gas-phase water permeation caused by the repeated opening and closing of interfacial micro-gap under temperature cycling.

Description

Technical Field

[0001] This invention belongs to the field of polymer material preparation technology, specifically relating to an organic sealing and protective composite material for power equipment and its preparation method. Background Technology

[0002] The dense arrangement of internal components in power equipment makes it prone to arcing and localized overheating during long-term continuous operation. Furthermore, the installation and sealing of various power equipment, such as substations, ring main units, and terminal boxes, generally face multiple protection requirements, including moisture-proofing, waterproofing, and fireproofing. Existing insulating coatings for power equipment are mostly made of a single material and lack flame-retardant properties. In the event of a fire, these coatings are easily ignited and produce molten droplets, further exacerbating the spread of the fire. Some flame-retardant coatings suffer from poor insulation and insufficient adhesion to the substrate, leading to easy peeling after application. Additionally, some products have an irritating odor, making them unsuitable for the enclosed environment inside equipment. Traditional equipment sealing in power construction often uses fire-retardant putty, which has significant limitations in its protective effect. Fire-retardant putty softens and collapses under high temperatures and cracks and breaks under low-temperature, dry conditions, making it difficult to form a continuous and effective sealing structure. This not only fails to effectively prevent moisture intrusion, easily causing condensation inside the equipment and leading to short circuits, but also allows small animals such as rats, snakes, and squirrels to enter through gaps in the seal and nest, creating additional safety hazards for equipment operation.

[0003] Existing technologies have solved some protection problems to a certain extent, but they have not addressed a hidden and long-standing technical challenge: electrochemical corrosion, decreased insulation resistance, and surface discharge defects still exist during equipment operation, which seriously affect the long-term operational reliability of the equipment. Summary of the Invention

[0004] The purpose of this invention is to provide an organic sealing and protective composite material for power equipment and its preparation method. The organic sealing and protective composite material provided by this invention can actively adapt to temperature changes and deform, dynamically compensate for interfacial thermal mismatch, and block the permeation of gas phase water, thus overcoming the defect of gas phase water permeation in protective materials caused by the micro-interface breathing effect under temperature cycling and electric field coupling.

[0005] To achieve the objectives of this invention, the following technical solutions are provided: An organic sealing and protective composite material for power equipment includes an electric field conducting substrate and an electroactive sealing layer disposed on the surface of the electric field conducting substrate; The raw materials for preparing the electric field conducting layer, by mass fraction, include: 10-30 parts of conductive polymer and 5-15 parts of first silane coupling agent; The electroactive sealing layer comprises component A and component B; The raw materials for preparing component A, by mass fraction, include: 60-80 parts of acrylate dielectric elastomer, 10-30 parts of dielectric ceramic filler, 2-5 parts of crosslinking agent, and 5-10 parts of flame retardant; the raw materials for preparing component B include: 60-80 parts of isocyanate, 5-15 parts of second silane coupling agent, 5-10 parts of latent curing agent, and 5-15 parts of plasticizer; the mass ratio of component A to component B is 2-3:1.

[0006] Preferably, the conductive polymer comprises poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate and / or polyaniline.

[0007] Preferably, the first silane coupling agent and the second silane coupling agent independently comprise c - Glycidyl etheroxypropyltrimethoxysilane and / or c -Aminopropyltriethoxysilane.

[0008] Preferably, the raw materials for preparing the electric field conducting layer further include 30-50 parts of terminal silane polyether resin.

[0009] Preferably, the acrylate dielectric elastomer is a polyurethane acrylate oligomer; The dielectric ceramic filler is barium titanate and / or barium strontium titanate; The crosslinking agent is IPDI trimer; The flame retardant is triphenyl phosphate.

[0010] Preferably, component A in the electroactive sealing layer further includes 5-15 parts of ionic liquid; The ionic liquid is 1-ethyl-3-methylimidazolium tetrafluoroborate.

[0011] Preferably, a flexible conductive layer is further disposed on the surface of the electroactive sealing layer; The raw materials for preparing the flexible conductive layer, by mass fraction, include: 70-90 parts of silicone rubber matrix and 10-30 parts of conductive filler; The conductive filler includes one or more of carbon nanotubes, graphene, and conductive carbon black.

[0012] Preferably, the ratio of the thickness of the electric field conducting layer to the thickness of the electroactive sealing layer is 1~5:300~1000.

[0013] This invention also provides a method for preparing the organic sealing and protective composite material for power equipment described in the above technical solution, comprising the following steps: A conductive polymer, a first silane coupling agent, and an organic solvent are mixed to obtain an electric field conducting bottom slurry; The electric field conducting underlayer paste is coated on the surface of a metal substrate, and after the first curing, an electric field conducting underlayer is obtained. The raw materials for preparing components A and B in the electroactive sealing layer are mixed to obtain the electroactive sealing layer slurry. The electroactive sealing layer slurry is coated onto the surface of the electric field conducting substrate, and after a second curing, the organic sealing and protective composite material for power equipment is obtained. Alternatively, a flexible conductive layer slurry can be obtained by mixing a silicone rubber matrix with conductive fillers; An electroactive sealing layer slurry and a flexible conductive layer slurry are sequentially coated on the surface of the electric field conducting bottom layer, and after curing, the organic sealing and protective composite material for power equipment is obtained.

[0014] Preferably, the second curing process includes pre-curing and temperature-curing performed sequentially; The pre-curing temperature is 20~25℃, and the holding time is 2~4h; the heating curing temperature is 60~80℃, and the holding time is 6~12h.

[0015] This invention provides an organic sealing and protective composite material for power equipment, comprising an electric field conducting substrate and an electroactive sealing layer disposed on the surface of the electric field conducting substrate. The electric field conducting substrate is prepared from the following raw materials by mass: 10-30 parts of a conductive polymer and 5-15 parts of a first silane coupling agent. The electroactive sealing layer comprises component A and component B. Component A is prepared from the following raw materials by mass: 60-80 parts of an acrylate dielectric elastomer, 10-30 parts of a dielectric ceramic filler, 2-5 parts of a crosslinking agent, and 5-10 parts of a flame retardant. Component B is prepared from the following raw materials: 60-80 parts of an isocyanate, 5-15 parts of a second silane coupling agent, 5-10 parts of a latent curing agent, and 5-15 parts of a plasticizer. The mass ratio of component A to component B is 2-3:1. Typically, there is a significant difference in the coefficient of thermal expansion between the metal matrix and the organic sealing material. Under temperature cycling and electric field coupling, periodic shear stress is generated at the interface, forming micron-level breathing effect gaps. This gap allows for the continuous infiltration of vapor-phase water molecules, forming concealed condensation in the low-temperature region inside the equipment, leading to defects such as electrochemical corrosion, decreased insulation resistance, and surface discharge. The present invention addresses this by placing an electric field conducting layer on the surface of a metal substrate. This layer comprises a conductive polymer and a silane coupling agent. The silane coupling agent forms a chemical bond with the metal substrate, ensuring the conductive polymer adheres firmly to the metal surface. The conductive polymer conducts the electric field generated during equipment operation to the surface of the layer, providing an energy source for subsequent electroactive responses. An electroactive sealing layer is disposed above the electric field conducting layer and comprises a dielectric elastomer matrix and a high-dielectric filler. When the equipment is powered on, the electric field is applied to the electroactive sealing layer through the electric field conducting layer. Under the influence of the electric field, this layer undergoes electrostrictive deformation—contracting along the thickness direction and expanding in the planar direction—actively increasing the interfacial contact pressure between the sealing layer and the metal substrate. This active deformation can compensate in real time for the difference in thermal expansion between the metal substrate and the sealing layer caused by temperature changes, filling any micro-gaps that may occur at the interface to block the infiltration channels of vapor-phase water. This application transforms the electric field that might have accelerated insulation degradation into a driving force for actively compensating for interfacial thermal mismatch, enabling the sealing and protective material to change from passively bearing stress to actively responding to deformation, fundamentally solving the problem of gas phase water permeation caused by repeated opening and closing of interfacial micro-gap under temperature cycling. Detailed Implementation

[0016] This invention provides an organic sealing and protective composite material for power equipment, comprising an electric field conducting substrate and an electroactive sealing layer disposed on the surface of the electric field conducting substrate; The raw materials for preparing the electric field conducting layer, by mass fraction, include: 10-30 parts of conductive polymer and 5-15 parts of first silane coupling agent; The electroactive sealing layer comprises component A and component B; The raw materials for preparing component A, by mass fraction, include: 60-80 parts of acrylate dielectric elastomer, 10-30 parts of dielectric ceramic filler, 2-5 parts of crosslinking agent, and 5-10 parts of flame retardant; the raw materials for preparing component B include: 60-80 parts of isocyanate, 5-15 parts of second silane coupling agent, 5-10 parts of latent curing agent, and 5-15 parts of plasticizer; the mass ratio of component A to component B is 2-3:1.

[0017] In this invention, unless otherwise specified, all raw materials are derived from commercially available products known to those skilled in the art or prepared using methods known to those skilled in the art.

[0018] In this invention, the raw materials for preparing the electric field conducting layer include 10 to 30 parts of conductive polymer by mass, and in specific embodiments, it can be 15, 20 or 27 parts; the conductive polymer includes poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT:PSS) and / or polyaniline.

[0019] In this invention, based on the mass fraction of the conductive polymer, the raw materials for preparing the electric field conducting layer include 5 to 15 parts of a first silane coupling agent, which in specific embodiments can be 8, 10, or 13 parts; the first silane coupling agent includes one or more of γ-glycidoxypropyltrimethoxysilane (KH-560) and γ-aminopropyltriethoxysilane (KH-550), which in specific embodiments can be KH-560 and KH-550, wherein the mass ratio of KH-560 to KH-550 is 1 to 3: 1 to 3.

[0020] In this invention, based on the mass fraction of the conductive polymer, the raw materials for preparing the electric field conducting layer also include 20-40 parts of solvent, which may be 25 or 30 parts in specific embodiments; the solvent includes an alcohol solvent and water, the alcohol solvent may be ethanol or isopropanol, and the water is deionized water; the volume ratio of isopropanol to water is 7:3.

[0021] In this invention, PEDOT:PSS and polyaniline are both commonly used conductive polymers in the field, exhibiting good film-forming properties and high chemical stability, enabling them to form a uniform thin-layer conductive network on the metal surface. The epoxy groups of KH-560 react with the hydroxyl groups on the metal surface, while the amino groups of KH-550 form a strong bond with the metal oxide layer. The synergistic effect of the two coupling agents allows them to adapt to different metal surface conditions. This invention achieves molecular-level mixing by selecting PEDOT:PSS and KH-560 / KH-550 as a compound and dissolving them in a mixed solvent of isopropanol / water, thus obtaining stable interfacial adhesion while ensuring conductivity. If the conductive polymer and silane coupling agent are not mixed evenly, the conductive network may be diluted and become ineffective.

[0022] In this invention, based on the mass fraction of the conductive polymer, the raw materials for preparing the electric field conducting layer also include 30-50 parts of terminal silane polyether resin, which in specific embodiments can be 33, 35, 40, 43, or 45 parts; the terminal silane polyether resin can specifically be a silane-terminated polyether (CAS No. 75009-88-0); the number average molecular weight of the terminal silane polyether resin is 2000-4000. In this invention, one end of the terminal silane polyether resin forms a cross-linked network with the components in the electric field conducting layer through silane groups, while the other end chemically reacts with the active groups in the electroactive sealing layer, forming a covalent bond between the two layers. This eliminates the interlayer interface caused by physical bonding in traditional multilayer structures and avoids the risk of interlayer delamination due to the different shrinkage rates of the two layers under temperature cycling.

[0023] In this invention, the electroactive sealing layer comprises component A and component B; by mass fraction, the raw materials for preparing component A include 60-80 parts of acrylate dielectric elastomer, which may be 65, 70 or 75 parts in specific embodiments; the acrylate dielectric elastomer is a polyurethane acrylate oligomer, specifically an aliphatic polyurethane acrylate (68987-79-1).

[0024] In this invention, based on the mass fraction of the acrylate dielectric elastomer, the raw materials for preparing component A include 10-30 parts of dielectric ceramic filler, which in specific embodiments can be 15, 18, 20, 27, or 29 parts; the dielectric ceramic filler is barium carbonate or barium strontium titanate; the particle size of the dielectric ceramic filler is 50-200 nm. In this invention, the dielectric ceramic filler is used to improve the dielectric constant of the electroactive sealing layer and enhance the response amplitude of the electrostrictive deformation.

[0025] In this invention, based on the mass fraction of the acrylate dielectric elastomer, the raw materials for preparing component A include 2 to 5 parts of a crosslinking agent, which may be 3 or 4 parts in specific embodiments; the crosslinking agent is IPDI trimer.

[0026] In this invention, based on the mass fraction of the acrylate dielectric elastomer, the raw materials for preparing component A include 5 to 10 parts of flame retardant, which may be 6 or 8 parts in specific embodiments; the flame retardant is triphenyl phosphate.

[0027] In this invention, based on the mass fraction of the acrylate dielectric elastomer, the raw materials for preparing component A also include 5-15 parts of an ionic liquid, which in specific embodiments can be 7, 8, or 13 parts; the ionic liquid is 1-ethyl-3-methylimidazolium tetrafluoroborate. In this invention, the ionic liquid can reduce the elastic modulus of the dielectric elastomer and increase its dielectric constant, enabling the electroactive sealing layer to produce the electrostrictive deformation under a relatively low electric field strength.

[0028] In this invention, the raw materials for preparing component B include 60 to 80 parts of isocyanate by mass, and in specific embodiments, it can be 65, 70, or 75 parts; the isocyanate can be HDI trimer.

[0029] In this invention, based on the mass fraction of isocyanate, the raw materials for preparing component B include 5 to 15 parts of a second silane coupling agent, which may be 8 or 10 parts in specific embodiments; the silane coupling agent may be the same as the silane coupling agent described above, and will not be repeated here.

[0030] In this invention, based on the mass fraction of isocyanate, the raw materials for preparing component B include 5 to 10 parts of a latent curing agent, which may be 7 or 12 parts in specific embodiments; the latent curing agent is an oxazolidine curing agent.

[0031] In this invention, based on the mass fraction of isocyanate, the raw materials for preparing component B include 5 to 15 parts of plasticizer, which may be 10 or 13 parts in specific embodiments; the plasticizer is a phthalate plasticizer, specifically diisononyl phthalate.

[0032] In this invention, the mass ratio of component A to component B is 2~3:1.

[0033] In this invention, a flexible conductive layer is further provided on the surface of the electroactive sealing layer; by mass fraction, the raw materials for preparing the flexible conductive layer include 70 to 90 parts of silicone rubber matrix, which in specific embodiments can be 73, 78, 80 or 85 parts; the silicone rubber matrix includes addition-type liquid silicone rubber or condensation-type room temperature vulcanizing silicone rubber.

[0034] In this invention, based on the mass fraction of the silicone rubber matrix, the raw materials for preparing the flexible conductive layer include 10-30 parts of conductive filler, which in specific embodiments can be 15, 20, 22, or 27 parts; the conductive filler includes one or more of carbon nanotubes, graphene, or conductive carbon black. In this invention, a driving electric field is formed between the flexible conductive layer (such as a carbon nanotube / silicone rubber composite material) and the metal substrate. The electric field strength of the driving electric field is 10-200 V / μm, used to provide a stable electric driving force independent of the device's operating voltage.

[0035] In this invention, the ratio of the thickness of the electric field conducting layer to the thickness of the electroactive sealing layer is 1~5:300~1000; in a specific embodiment, the thickness of the electric field conducting layer is 10~50μm, the thickness of the electroactive sealing layer is 3~10mm, and the thickness of the flexible conductive layer is 50~100μm; in this invention, the thickness refers to the thickness of the dry film after curing.

[0036] In this invention, if the thickness of the electric field conducting layer is too thin, the conductive network will be discontinuous and the electric field distribution will be uneven; if the thickness is too thick, the resistance of the electric field conducting layer will be too low, which may generate a large leakage current and affect the insulation safety. If the thickness of the electroactive sealing layer is too thin, the deformation space will be insufficient, making it difficult to compensate for interface gaps; if the thickness is too thick, the electric field strength will be significantly attenuated, and the driving efficiency will decrease. This invention controls the thickness ratio within the range of 1~5:300~1000, which can ensure a uniform electric field distribution while keeping the leakage current below the milliampere level, without significantly affecting the overall insulation performance.

[0037] This invention also provides a method for preparing the organic sealing and protective composite material for power equipment described in the above technical solution, comprising the following steps: A conductive polymer, a first silane coupling agent, and an organic solvent are mixed to obtain an electric field conducting bottom slurry; The electric field conducting underlayer paste is coated on the surface of a metal substrate, and after the first curing, an electric field conducting underlayer is obtained. The raw materials for preparing components A and B in the electroactive sealing layer are mixed to obtain the electroactive sealing layer slurry. The electroactive sealing layer slurry is coated onto the surface of the electric field conducting substrate, and after a second curing, the organic sealing and protective composite material for power equipment is obtained. Alternatively, a flexible conductive layer slurry can be obtained by mixing a silicone rubber matrix with conductive fillers; The electroactive sealing layer slurry and the flexible conductive layer slurry are sequentially coated on the surface of the electric field conducting bottom layer, and after curing, the organic sealing and protective composite material for power equipment is obtained.

[0038] This invention does not impose any special limitations on the metal substrate.

[0039] This invention involves coating an electric field conducting underlayer slurry onto the surface of a metal substrate, followed by a first curing to obtain the electric field conducting underlayer. This invention does not have specific limitations on the electric field conducting underlayer slurry used; in specific embodiments, it can be applied by air spraying. The nozzle diameter of the air spray gun can be 0.5~0.8mm, and the spraying pressure can be 0.3~0.5MPa. This invention does not limit the number of spraying passes, as long as the dry film thickness is 10~50μm. The first curing temperature is 20~25℃, and the holding time is 2~4h.

[0040] After obtaining the electric field conducting underlayer, the present invention coats the surface of the electric field conducting underlayer with an electroactive sealing layer slurry, and after a second curing, obtains the organic sealing and protective composite material for power equipment. The present invention does not have a specific limitation on the electroactive sealing layer slurry; in specific embodiments, it can be applied by scraping. The second curing includes sequential pre-curing and thermal curing; the pre-curing temperature is 20~25℃, and the holding time is 2~4 hours; the thermal curing temperature is 60~80℃, and in specific embodiments, it can be 65 or 70℃, and the holding time is 6~12 hours; the heating rate from pre-curing to the required thermal curing temperature is 0.5~1.0℃ / min.

[0041] In this invention, when the organic sealing and protective composite material for power equipment includes a flexible conductive layer, after obtaining the electric field conducting bottom layer, an electroactive sealing layer slurry and a flexible conductive layer slurry are sequentially coated on the surface of the electric field conducting bottom layer, and after a second curing, the organic sealing and protective composite material for power equipment is obtained.

[0042] This invention employs a gradient curing process to treat the electroactive sealing layer, enabling the material to form a uniform, stress-free cross-linked network during curing. Simultaneously, chemical cross-linking occurs between the electric field-conducting underlayer and the electroactive sealing layer via terminal silane-based polyether resin, eliminating the interlayer interface. This invention matches parameters during the curing process of the two layers; if the electric field-conducting underlayer cures too quickly while the electroactive sealing layer cures lags behind, insufficient reactivity at the interface prevents chemical cross-linking; if the electric field-conducting underlayer cures too slowly, the structure of this layer may be damaged when the electroactive sealing layer slurry is poured. This application selects an electric field-conducting underlayer slurry that cures rapidly at room temperature (2-4 hours) in conjunction with the gradient-cured sealing layer, ensuring that the two layers overlap within the curing time window and that sufficient interfacial chemical cross-linking occurs. Furthermore, the sequential pre-curing and temperature-curing processes of this invention, through gradient curing, eliminate internal stress and microscopic defects, ensuring that the electroactive sealing layer maintains stable deformation response capabilities during long-term use.

[0043] To further illustrate the present invention, the organic sealing and protective composite material for power equipment and its preparation method provided by the present invention are described in detail below with reference to embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0044] Example 1 Weigh 20 parts by weight of PEDOT:PSS aqueous dispersion (solid content 1.3wt%), 5 parts by weight of KH-560 silane coupling agent, 5 parts by weight of KH-550 silane coupling agent, 40 parts by weight of silyl-terminated polyether, 20 parts by weight of isopropanol and 10 parts by weight of deionized water, and stir and mix them at room temperature (23±2℃) for 30 min to obtain an electric field conducting underlayer slurry. Apply the electric field conducting underlayer slurry to the surface of the metal substrate by air spraying: use a spray gun with a nozzle diameter of 0.5 mm, a spraying pressure of 0.3 MPa, and spray twice to achieve a dry film thickness of 30 μm. Cure at room temperature for 2 h to obtain the electric field conducting underlayer.

[0045] 20 parts by mass of barium titanate nanoparticles and 65 parts by mass of aliphatic polyurethane acrylate were mixed at 2000 rpm for 30 min. Then, 10 parts by mass of 1-ethyl-3-methylimidazolium tetrafluoroborate, 3 parts by mass of IPDI trimer, and 8 parts by mass of triphenyl phosphate were added, and the mixture was stirred for another 15 min to obtain electroactive sealing layer A slurry. 70 parts by mass of HDI trimer, 10 parts by mass of KH-560 silane coupling agent, 8 parts by mass of oxazolidine latent curing agent (TP-820), and 12 parts by mass of diisononyl phthalate were mixed and stirred evenly to obtain electroactive sealing layer B slurry. Electroactive sealing layer A and B slurries were mixed and slowly poured onto the surface of the above electric field conducting substrate, controlling the dry film thickness to 5 mm. The mixture was first pre-cured at room temperature (23±2℃) for 3 h, then heated from room temperature to 70℃ at a rate of 0.8℃ / min and held for 8 h to cure. The mixture was then allowed to cool naturally to room temperature to obtain the electroactive sealing layer.

[0046] 80 parts by weight of addition-type liquid silicone rubber and 20 parts by weight of multi-walled carbon nanotubes were dispersed three times in a three-roll mill to obtain a flexible conductive layer slurry. Before the above-mentioned electroactive sealing layer was completely cured (i.e., 2 hours after being poured onto the surface of the electric field conducting bottom layer), the flexible conductive layer slurry was scraped onto the surface of the electroactive sealing layer, with a dry film thickness of about 100 μm. Then, it was gradient cured together with the above-mentioned electroactive sealing layer to obtain an organic sealing and protective composite material.

[0047] Example 2 The organic sealing and protective composite material was prepared according to the preparation method described in Example 1, except that 10 parts by weight of 1-ethyl-3-methylimidazolium tetrafluoroborate were not added to the electroactive sealing layer A slurry.

[0048] Example 3 The organic sealing and protective composite material was prepared according to the preparation method described in Example 1, except that: the electroactive sealing layer A and B slurries were mixed and slowly poured onto the surface of the above-mentioned electric field conducting bottom layer, and then placed in a 70°C oven for heat preservation and curing for 8 hours.

[0049] Example 4 The organic sealing and protective composite material was prepared according to the preparation method described in Example 1, except that a flexible conductive layer was not provided.

[0050] Comparative Example 1 The organic sealing and protective composite material was prepared according to the preparation method described in Example 1, except that 20 parts by mass of PEDOT:PSS aqueous dispersion was not added to the electric field conduction bottom slurry.

[0051] Comparative Example 2 The organic sealing and protective composite material was prepared according to the preparation method described in Example 1, except that 65 parts by weight of aliphatic polyurethane acrylate were not added to the electroactive sealing layer A slurry.

[0052] Test case The following tests were performed on the organic sealing and protective composite materials obtained in Examples 1-4 and Comparative Examples 1-2: 1) Electrostrictive strain test: A 500V DC voltage (electric field strength calculated based on the thickness of the electroactive sealing layer) is applied between the flexible conductive layer of the sample and the metal substrate. A laser displacement sensor is used to measure the thickness change of the central region of the electroactive sealing layer before and after the voltage is applied. The shrinkage strain in the thickness direction is calculated according to the following formula: Strain (%) = (Initial thickness - Thickness after voltage application) / Initial thickness × 100%.

[0053] 2) Water vapor transmission rate test: The sample is sealed in a permeation cup and tested for 24 hours at 38℃ and 90% relative humidity. The mass change of the permeation cup is measured, and the water vapor transmission rate (g / (m)) is calculated. 2 ·d)).

[0054] 3) Interfacial Shear Strength Retention Rate Test: The organic sealing and protective composite material was coated onto the overlapping surface of two metal substrates (overlap length 12.5 mm). After curing, the initial shear strength was tested. Another identical sample was subjected to a temperature cycling test (-40℃ to 80℃, heating rate 2℃ / min, holding time 2 hours, for a total of 100 cycles). After cycling, the shear strength was tested. The retention rate was calculated using the following formula: Retention rate (%) = Strength after cycling / Initial strength × 100%.

[0055] The test results are shown in Table 1.

[0056] Table 1. Performance test results of the organic sealing and protective composite materials obtained in Examples 1-4 and Comparative Examples 1-2.

[0057] As shown in Table 1, the electrostrictive strain of Example 1 reached 7.2%, and the water vapor permeability was only 0.12 g / (m²).2 •d) The interfacial shear strength retention rate reached 92%, while the electrostrictive strain of Comparative Example 1 (without conductive polymer in the bottom layer) and Comparative Example 2 (without dielectric elastomer in the electroactive sealing layer) were both 0%, and the water vapor permeability was as high as 1.85 and 2.10 g / (m²), respectively. 2 •d) Retention rates are only 45% and 35%. This proves that the present invention introduces an electric field through the electric field conduction layer and generates electrostrictive deformation through the electroactive sealing layer. The two work together to transform the electric field into a driving force for actively compensating for interfacial thermal mismatch, fundamentally solving the problem of gas phase water permeation caused by repeated opening and closing of interfacial micro-gap under temperature cycling.

[0058] Example 2 (non-ionic liquid): Due to insufficient deformation (2.8%), the water vapor permeability increased to 0.45 g / (m³). 2 •d) This demonstrates that ionic liquids, by reducing modulus and increasing dielectric constant, enable the sealing layer to undergo sufficient deformation under a lower electric field. Example 3 (without gradient curing) showed acceptable deformation (6.5%), but internal stress caused the interfacial shear strength retention rate to drop to 68%, and the water vapor permeability to increase to 0.38 g / (m²). 2 •d) demonstrates that gradient curing ensures long-term interface stability by eliminating internal stress. Example 4 (without a flexible conductive layer) showed only 2.5% deformation due to insufficient drive on a 380V device, and the water vapor permeability increased to 0.68 g / (m²). 2 ·d), demonstrating that the flexible conductive layer provides an independent and stable electric field driving force for low-voltage devices.

[0059] In summary, this invention transforms the electric field that could have accelerated insulation degradation into a driving force that actively compensates for interfacial thermal mismatch, enabling the sealing material to shift from passively bearing stress to actively responding to deformation, thus fundamentally solving the problem of gas phase water permeation caused by repeated opening and closing of interfacial micro-gap under temperature cycling.

[0060] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. An organic sealing and protective composite material for power equipment, characterized in that, It includes an electric field conducting layer and an electrically active sealing layer disposed on the surface of the electric field conducting layer; The raw materials for preparing the electric field conducting layer, by mass fraction, include: 10-30 parts of conductive polymer and 5-15 parts of first silane coupling agent; The electroactive sealing layer comprises component A and component B; The raw materials for preparing component A, by mass fraction, include: 60-80 parts of acrylate dielectric elastomer, 10-30 parts of dielectric ceramic filler, 2-5 parts of crosslinking agent, and 5-10 parts of flame retardant; the raw materials for preparing component B include: 60-80 parts of isocyanate, 5-15 parts of second silane coupling agent, 5-10 parts of latent curing agent, and 5-15 parts of plasticizer; the mass ratio of component A to component B is 2-3:

1.

2. The organic sealing and protective composite material for power equipment according to claim 1, characterized in that, The conductive polymer includes poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate and / or polyaniline.

3. The organic sealing and protective composite material for power equipment according to claim 1, characterized in that, The first silane coupling agent and the second silane coupling agent independently comprise γ - Glycidyl etheroxypropyltrimethoxysilane and / or γ -Aminopropyltriethoxysilane.

4. The organic sealing and protective composite material for power equipment according to claim 1, characterized in that, The raw materials for preparing the electric field conduction layer also include 30-50 parts of terminal silane polyether resin.

5. The organic sealing and protective composite material for power equipment according to claim 1, characterized in that, The acrylate dielectric elastomer is a polyurethane acrylate oligomer; The dielectric ceramic filler is barium titanate and / or barium strontium titanate; The crosslinking agent is IPDI trimer; The flame retardant is triphenyl phosphate.

6. The organic sealing and protective composite material for power equipment according to claim 1, characterized in that, Component A in the electroactive sealing layer also includes 5-15 parts of ionic liquid; The ionic liquid is 1-ethyl-3-methylimidazolium tetrafluoroborate.

7. The organic sealing and protective composite material for power equipment according to claim 1, characterized in that, A flexible conductive layer is also provided on the surface of the electroactive sealing layer; The raw materials for preparing the flexible conductive layer, by mass fraction, include: 70-90 parts of silicone rubber matrix and 10-30 parts of conductive filler; The conductive filler includes one or more of carbon nanotubes, graphene, and conductive carbon black.

8. The organic sealing and protective composite material for power equipment according to claim 1, characterized in that, The ratio of the thickness of the electric field conducting layer to the thickness of the electroactive sealing layer is 1~5:300~1000.

9. A method for preparing the organic sealing and protective composite material for power equipment according to any one of claims 1 to 8, characterized in that, Includes the following steps: A conductive polymer, a first silane coupling agent, and an organic solvent are mixed to obtain an electric field conducting bottom slurry; The electric field conducting underlayer paste is coated on the surface of a metal substrate, and after the first curing, an electric field conducting underlayer is obtained. The raw materials for preparing components A and B in the electroactive sealing layer are mixed to obtain the electroactive sealing layer slurry. The electroactive sealing layer slurry is coated onto the surface of the electric field conducting substrate, and after a second curing, the organic sealing and protective composite material for power equipment is obtained. Alternatively, a flexible conductive layer slurry can be obtained by mixing a silicone rubber matrix with conductive fillers; The electroactive sealing layer slurry and the flexible conductive layer slurry are sequentially coated on the surface of the electric field conducting bottom layer, and after curing, the organic sealing and protective composite material for power equipment is obtained.

10. The preparation method according to claim 9, characterized in that, The second curing process includes sequential pre-curing and temperature-induced curing; The pre-curing temperature is 20~25℃, and the holding time is 2~4h; the heating curing temperature is 60~80℃, and the holding time is 6~12h.

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