Niobium carbide and ethylene-butadiene rubber liquid-phase composite material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of sealing materials, and discloses a niobium carbide and ethylene-butadiene rubber liquid-phase composite material as well as a preparation method and application thereof. The niobium carbide and ethylene-butadiene rubber liquid-phase composite material comprises an ethylene-butadiene rubber matrix and a niobium carbide nano filler dispersed in the matrix, wherein the niobium carbide nanofiller is chemically bonded with a molecular chain of the ethylene-butadiene rubber through a coupling agent, and the content of the niobium carbide nanofiller is 1-5% of the mass of the ethylene-butadiene rubber. Through an innovative liquid-phase compounding process, highly uniform dispersion and strong interface chemical bonding of nano niobium carbide in an ethylene-butadiene rubber matrix are realized, a rubber sealing product prepared from the niobium carbide and ethylene-butadiene rubber liquid-phase composite material comprehensively replaces ethylene-butadiene rubber, and the rubber sealing product has excellent elasticity while maintaining excellent elasticity. The comprehensive mechanical property and the high-temperature aging resistance are synergistically improved; the tensile strength and the elongation at break are synchronously increased at normal temperature; and after long-term thermal aging at 125-150 DEG C, the compression set rate is remarkably reduced, and the sealing retention is excellent.

Description

Technical Field

[0001] This invention relates to the field of sealing materials technology, and in particular to a niobium carbide and ethylene butyl rubber liquid phase composite material, its preparation method and application. Background Technology

[0002] As a critical national infrastructure, the stable operation of the power system is directly related to social and economic security and people's livelihood. In various stages of power generation, transmission, and transformation, a large number of electrical devices rely on rubber seals to provide functions such as dustproofing, waterproofing, corrosion protection, and insulation. However, power equipment often operates in high-temperature environments. For example, the temperature of high-voltage switches, transformers, and cable joints can reach over 100°C due to the thermal effect of current or the accumulation of ambient heat, and may even remain at around 150°C for extended periods. Under these conditions, ordinary rubber seals are highly susceptible to thermo-oxidative aging, leading to a sharp decline in their physical and mechanical properties. This manifests as reduced tensile strength, decreased elastic modulus, increased hardness, and increased compression set, ultimately causing seal failure and resulting in serious accidents such as decreased equipment insulation performance, media leakage, short circuits, and even fires.

[0003] Currently, the main approaches to improving the high-temperature resistance of rubber in the industry include adding antioxidants and using reinforcing fillers. While common antioxidants such as amines and phenols can delay aging to some extent, they exhibit poor dispersibility in the rubber matrix, are prone to migration, have insufficient durability, and their protective effect significantly diminishes under long-term high temperatures. On the other hand, conventional reinforcing fillers such as carbon black and silica are primarily used to improve the mechanical strength of rubber, with limited effect on improving high-temperature resistance. Furthermore, excessive filling can lead to decreased rubber elasticity and deterioration of processing performance.

[0004] In recent years, nanofillers (such as nano-silica and carbon nanotubes) have been introduced into rubber modification research due to their high specific surface area and unique interfacial effects, with the potential to simultaneously enhance mechanical properties and thermal stability. However, the uniform dispersion of nanofillers in rubber remains a major technical challenge. Traditional mechanical blending methods (dry mixing) easily lead to nanoparticle agglomeration, forming stress concentration points. This not only fails to leverage the nano-effects but also reduces the toughness and fatigue life of the rubber. Furthermore, the interfacial bonding strength between nanofillers and the rubber matrix is ​​insufficient, making them prone to interfacial debonding under high temperatures or dynamic loads, thus accelerating material failure.

[0005] Therefore, developing a new composite material and its preparation process that can achieve high dispersion and strong interfacial bonding of nanofillers and significantly improve the high-temperature aging resistance of rubber has become a technical bottleneck that urgently needs to be overcome in the field of sealing materials for power equipment. Summary of the Invention

[0006] The present invention aims to at least solve one of the aforementioned technical problems existing in the prior art. Therefore, one objective of the present invention is to provide a niobium carbide and ethylene-butyl rubber liquid-phase composite material.

[0007] The second objective of this invention is to provide a method for preparing this niobium carbide and ethylene butyl rubber liquid phase composite material.

[0008] The third objective of this invention is to provide a rubber sealing product.

[0009] The fourth objective of this invention is to provide a method for preparing such a rubber sealing product.

[0010] The fifth objective of this invention is to provide applications for such rubber sealing products.

[0011] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first aspect of the present invention provides a niobium carbide and ethylene butyl rubber liquid phase composite material, comprising an ethylene butyl rubber matrix and niobium carbide nanofiller dispersed in the matrix; wherein the niobium carbide nanofiller is chemically bonded to the molecular chain of ethylene butyl rubber by a coupling agent, and its content is 1%-5% of the mass of ethylene butyl rubber.

[0012] In some embodiments of the present invention, the content of the niobium carbide nanofiller in the niobium carbide-butyl rubber liquid phase composite material is 2%-4% of the mass of butyl rubber.

[0013] In some embodiments of the present invention, the niobium carbide nanofiller is prepared by a method comprising the following steps: dispersing micron-sized niobium carbide in an alcohol solution, adding an anionic surfactant, and ultrasonically treating to obtain the niobium carbide nanofiller with a particle size of 20-40 nm.

[0014] In some embodiments of the present invention, the particle size of the micron-sized niobium carbide is 2-4 μm.

[0015] In some embodiments of the present invention, the volume concentration of the alcohol solution is 85%-95%.

[0016] In some preferred embodiments of the present invention, the volume concentration of the alcohol solution is 90%-95%.

[0017] In some embodiments of the present invention, the alcohol solution comprises an aqueous solution of ethanol.

[0018] In some embodiments of the present invention, the solid-liquid ratio of the micron-sized niobium carbide to the alcohol solution is 1 g: (5-10) mL.

[0019] In some embodiments of the present invention, the process of dispersing the micron-sized niobium carbide in the alcohol solution is aided by stirring, with a stirring speed of 300-500 r / min and a stirring time of 15-30 min.

[0020] Specifically, limiting the ratio of micron-sized niobium carbide to alcohol solution can ensure that the alcohol solution fully disperses the niobium carbide powder and avoid increased energy consumption in subsequent processing due to excessive solvent.

[0021] In some embodiments of the present invention, the amount of the anionic surfactant is 0.5%-2% of the mass of micron-sized niobium carbide.

[0022] In some embodiments of the present invention, the anionic surfactant includes sodium dodecylbenzenesulfonate.

[0023] Specifically, anionic surfactants can adsorb onto the surface of niobium carbide particles, reducing the surface tension between particles and significantly improving the dispersibility of the powder in solution.

[0024] In some embodiments of the present invention, after adding the anionic surfactant, the mixture is further stirred at a speed of 300-500 r / min for 10-20 min.

[0025] In some embodiments of the present invention, the ultrasonic treatment power is 300-500W and the time is 1-2h.

[0026] Specifically, ultrasonic treatment utilizes the high temperature and high pressure generated by the cavitation effect of ultrasound to instantly impact particle agglomerates, as well as the high frequency vibration under mechanical action, to homogenize micron-sized niobium carbide to nano-sized particles. The reduction in particle size leads to an exponential increase in specific surface area, providing a huge interfacial area for full contact with rubber.

[0027] In some embodiments of the present invention, after the ultrasonic treatment is completed, the solid phase is further separated by solid-liquid separation, dried, and the niobium carbide nanofiller is obtained.

[0028] In some embodiments of the present invention, the solid-liquid separation method is selected from centrifugation or filtration; the centrifugation speed is 5000-8000 r / min and the time is 10-20 min; the filtration includes using a filter membrane with a pore size of 0.2-0.5 μm.

[0029] In some embodiments of the present invention, the drying temperature is 80-100°C and the time is 4-6 hours.

[0030] In some embodiments of the present invention, the niobium carbide and ethylene butyl rubber liquid phase composite material comprises the following raw materials: ethylene butyl rubber, niobium carbide nanofiller, coupling agent, nonionic surfactant, flocculant and water.

[0031] In some embodiments of the present invention, the coupling agent includes a silane coupling agent.

[0032] In some preferred embodiments of the present invention, the coupling agent includes γ-aminopropyltriethoxysilane (KH-550).

[0033] In some embodiments of the present invention, the nonionic surfactant includes at least one of polyethylene glycol 400 (PEG-400) and fatty alcohol polyoxyethylene ether (AEO).

[0034] In some embodiments of the present invention, the flocculant includes polyacrylamide (PAM).

[0035] A second aspect of the present invention provides a method for preparing the niobium carbide and ethylene-butyl rubber liquid-phase composite material described in the first aspect of the present invention, comprising the following steps: S1. Niobium carbide nanofiller, nonionic surfactant and water are mixed to obtain niobium carbide dispersion; ethylene butyl rubber, nonionic surfactant and water are mixed to obtain ethylene butyl rubber dispersion. S2. Inject the niobium carbide dispersion into the ethylene butyl rubber dispersion, add a coupling agent, react, and obtain a mixture. S3. Add flocculant to the mixture to obtain composite material precursor; S4. The composite material precursor is pressed into sheets to obtain the niobium carbide and ethylene butyl rubber liquid phase composite material.

[0036] Specifically, this invention abandons the traditional solid-solid (dry powder-raw rubber) mechanical mixing, and slowly mixes the niobium carbide nanofiller dispersion with the ethylene-butyl rubber latex aqueous dispersion in the liquid phase. The electrostatic repulsion and steric hindrance of nonionic surfactants (such as sodium dodecylbenzenesulfonate, PEG-400) are used to maintain the stable dispersion of niobium carbide nanoparticles in the liquid phase, and to achieve uniform microscale penetration with rubber latex particles. The aqueous environment is also conducive to the hydrolysis of coupling agents and their initial reaction with the filler surface, creating conditions for complete bonding in the subsequent drying and vulcanization stage. This uniform micro-composite structure is fixed as a whole by flocculation, thus obtaining the precursor composite material.

[0037] In some embodiments of the present invention, the mass ratio of the niobium carbide nanofiller, the nonionic surfactant, and water is 1: (0.01-0.03): (10-20).

[0038] In some embodiments of the present invention, the process of mixing the niobium carbide nanofiller, nonionic surfactant and water is supplemented by stirring, with a stirring speed of 400-600 r / min and a stirring time of 20-30 min.

[0039] In some embodiments of the present invention, the mass ratio of the ethylene butyl rubber, nonionic surfactant and water is 1:(0.01-0.03):(10-20).

[0040] In some embodiments of the present invention, the process of mixing the ethylene butyl rubber, nonionic surfactant and water is supplemented by stirring, with a stirring speed of 300-500 r / min and a stirring time of 30-40 min.

[0041] In some embodiments of the present invention, the niobium carbide dispersion is injected into the ethylene butyl rubber dispersion at a rate of 5-10 mL / min.

[0042] In some embodiments of the present invention, the amount of the coupling agent is 1%-3% of the mass of the ethylene butyl rubber solution dispersion.

[0043] In some embodiments of the present invention, the reaction process is aided by stirring, including stirring at a speed of 100-200 r / min for 10-20 min, and then stirring at a speed of 400-600 r / min for 30-40 min.

[0044] In some embodiments of the present invention, the amount of flocculant used is 0.5%-2% of the mass of the mixture.

[0045] In some embodiments of the present invention, the addition of flocculant includes stirring for 10-20 minutes, letting stand for 1-2 hours, separating the solid phase by solid-liquid separation, drying, and obtaining the precursor of the composite material.

[0046] In some embodiments of the present invention, the drying temperature is 60-80°C and the time is 8-12 hours.

[0047] In some embodiments of the present invention, the temperature for tableting is 50-70°C.

[0048] Specifically, this temperature range allows ethylene butyl rubber to have good plasticity while avoiding excessively high temperatures that could lead to premature vulcanization or carbonization of the rubber and alter its properties.

[0049] In some embodiments of the present invention, the tableting process is carried out in an open mill with a roll gap of 1-2 mm and a rotation speed of 20-30 r / min.

[0050] In some embodiments of the present invention, after the tableting process is completed, a 12-24 hour resting period is also included.

[0051] Specifically, after compression, the rubber sheet is left to stand for 12-24 hours to allow the internal stress to be fully released, the molecular chains to rearrange, and the stability of the composite material to be improved.

[0052] A third aspect of the present invention provides a rubber sealing product, comprising, by weight, the following raw materials: 100-105 parts of niobium carbide and ethylene-butyl rubber liquid phase composite material, 55-75 parts of reinforcing filler, 1-3 parts of silane coupling agent, 3.5-5 parts of peroxide vulcanization system, and 1-5 parts of antioxidant; wherein the niobium carbide and ethylene-butyl rubber liquid phase composite material is as described in the first aspect of the present invention.

[0053] In some embodiments of the present invention, the reinforcing filler includes at least one of medium-high structure carbon black and large particle size low structure carbon black.

[0054] In some preferred embodiments of the present invention, the reinforcing filler is a compound of 25-35 parts by weight of medium-high structure carbon black and 30-40 parts by weight of large particle size low structure carbon black.

[0055] In some preferred embodiments of the present invention, the medium-high structure carbon black includes Cabot carbon black N550.

[0056] In some preferred embodiments of the present invention, the large particle size low structure carbon black includes Cabot carbon black N774.

[0057] In some embodiments of the present invention, the silane coupling agent includes γ-aminopropyltriethoxysilane (KH-550).

[0058] Specifically, this invention uses a combination of medium-high structure carbon black and large-particle-size low-structure carbon black. The medium-high structure carbon black imparts excellent mechanical strength, abrasion resistance, and processing fluidity to the rubber compound, while the large-particle-size low-structure carbon black focuses on improving the elasticity of the rubber compound and reducing dynamic heat generation and compression set. The combination of the two can form a composite reinforcing network in the rubber that combines rigidity and flexibility, balancing the dual requirements of sealing products for maintaining strength and adapting to deformation. The amount of large-particle-size low-structure carbon black in the formulation is slightly higher than that of medium-high structure carbon black, indicating that priority is given to ensuring the rebound sealing performance of the sealing ring, while supplementing mechanical strength, which is in line with the performance orientation of ethylene butyl rubber sealing rings that prioritizes sealing and takes strength as a secondary factor.

[0059] In some embodiments of the present invention, the peroxide vulcanization system includes a peroxide vulcanizing agent and a crosslinking agent.

[0060] In some preferred embodiments of the present invention, the peroxide vulcanization system is a compound of 2-3 parts peroxide vulcanizing agent and 0.5-1.5 parts crosslinking agent by weight.

[0061] In some preferred embodiments of the present invention, the peroxide sulfiding agent includes dicumyl peroxide (DCP).

[0062] In some preferred embodiments of the present invention, the co-crosslinking agent comprises 1,3,5-triallyl-triazine-2,4,6(1H,3H,5H)-trione (TAIC).

[0063] Specifically, a peroxide vulcanization system is selected, supplemented with a crosslinking agent. The CC crosslinking bonds formed by peroxides have high bond energy and thermal stability far superior to the polysulfide bonds (low bond energy, easy to thermally break) of traditional sulfur vulcanization. The crosslinking agent can further improve the crosslinking efficiency and density, making the rubber network more stable at high temperatures.

[0064] In some embodiments of the present invention, the antioxidant includes at least one of imidazole antioxidants and amine antioxidants.

[0065] In some preferred embodiments of the present invention, the antioxidant is a compound of 0.5-2.5 parts by weight of an imidazole antioxidant and 0.5-2.5 parts by weight of an amine antioxidant.

[0066] In some preferred embodiments of the present invention, the imidazole antioxidant includes 2-mercaptobenzimidazole (antioxidant MB).

[0067] In some preferred embodiments of the present invention, the amine antioxidant includes 4,4'-bis(α,α-dimethylbenzyl)diphenylamine (antioxidant 445).

[0068] Specifically, this invention combines imidazole and amine antioxidants, and their synergistic effect is manifested in the following four aspects: 1) The two antioxidants complementarily scavenge active free radicals at different stages of the thermo-oxidative aging chain reaction of rubber. The imidazole antioxidant can quickly capture aging-inducing peroxide free radicals (ROO·), while the amine antioxidant can effectively scavenge alkoxy free radicals (RO·) and alkyl free radicals (R·), thus achieving complete blocking of the oxidation reaction; 2) The imidazole antioxidant can passivate the catalytic oxidation activity of trace transition metal ions in the system, not only directly slowing down the catalytic oxidation of metal ions, but also... The aging process protects amine antioxidants from premature consumption, indirectly enhancing the durability of the entire protection system; 3) Due to differences in molecular weight and properties, imidazole antioxidants migrate quickly, providing rapid initial protection, while amine antioxidants migrate slowly but remain for a long time, providing long-term stability. The combination of the two achieves a time-complementary effect of immediate response and long-term stability; 4) The two have complementary and superimposed protective spectrums. Imidazole antioxidants focus on protection against thermo-oxidative aging and metal ion catalytic aging, while amine antioxidants, in addition to thermo-oxidative aging, also have anti-ozone aging function, thus covering a wider range of failure causes.

[0069] In some embodiments of the present invention, the raw materials for preparing the rubber sealing product further include 4-8 parts of vulcanizing activator and 1.5-2.5 parts of internal release agent by weight.

[0070] In some preferred embodiments of the present invention, the vulcanizing activator is a compound of 3.5-6.5 parts zinc oxide and 0.5-1.5 parts stearic acid by weight.

[0071] In some preferred embodiments of the present invention, the internal release agent includes Moldex MF-935P.

[0072] In some preferred embodiments of the present invention, the rubber sealing product comprises, by weight, the following raw materials: 102-104 parts of niobium carbide and ethylene-butyl rubber liquid phase composite material, 27-33 parts of medium-high structure carbon black, 32-37 parts of large particle size low structure carbon black, 1-3 parts of silane coupling agent, 2.4-2.6 parts of peroxide vulcanizing agent, 0.9-1.1 parts of co-crosslinking agent, 0.8-1.2 parts of imidazole antioxidant, 0.8-1.2 parts of amine antioxidant, 4-6 parts of zinc oxide, 0.8-1.2 parts of stearic acid, and 1.8-2.2 parts of internal release agent.

[0073] A fourth aspect of the present invention provides a method for preparing the rubber sealing article described in the third aspect of the present invention, comprising the following steps: The raw materials for preparing the rubber sealing product are mixed to obtain a compound; the compound is vulcanized to obtain the rubber sealing product.

[0074] In some embodiments of the present invention, the vulcanization temperature is 150-170°C, the pressure is 10-15 MPa, and the time is 15-25 min.

[0075] The fifth aspect of the invention provides the application of the rubber sealing product described in the third aspect of the invention in electrical equipment.

[0076] Compared with the prior art, the beneficial effects of the present invention are: The niobium carbide-ethylene-butyl rubber liquid-phase composite material provided by this invention achieves highly uniform dispersion and strong interfacial chemical bonding of nano-niobium carbide in the ethylene-butyl rubber matrix through an innovative liquid-phase composite process, fundamentally solving the technical bottleneck of filler agglomeration and weak interfacial bonding in traditional dry mixing. Rubber sealing products made by completely replacing ethylene-butyl rubber with the niobium carbide-ethylene-butyl rubber liquid-phase composite material maintain excellent elasticity while achieving synergistic improvement in comprehensive mechanical properties and high-temperature aging resistance: tensile strength and elongation at break increase simultaneously at room temperature; after long-term heat aging at 125-150℃, the compression set is significantly reduced, resulting in excellent sealing retention; furthermore, the synergistic effect of the composite anti-aging system (MB / 445), the complementarity of carbon black (N550 / N774), and the thermal stability of the peroxide vulcanization network jointly construct a multi-layered protection and reinforcement mechanism. When this sealing product is applied to high-temperature and harsh operating conditions such as power equipment, its service life can be significantly extended, and its reliability is significantly enhanced, providing key material support for achieving long-term safe operation of equipment. Detailed Implementation

[0077] The present invention will be further described in detail below through specific embodiments. Unless otherwise specified, the raw materials, reagents, or apparatus used in the embodiments and comparative examples are all available from conventional commercial sources or can be obtained by existing technical methods. Unless otherwise specified, the test or experimental methods are conventional methods in the art.

[0078] Note: 1. The open mill used in the following examples and comparative examples is a Φ160mm open mill from Jiangsu Tianhui Test Machinery Co., Ltd.; the flat vulcanizing machine is a 400×400mm flat vulcanizing machine from Dongguan Zhuosheng Machinery Equipment Co., Ltd.

[0079] 2. Unless otherwise specified, "parts" in the following examples and comparative examples refer to "parts by weight"; 3. The raw material information used in the following examples and comparative examples is shown in Table 1: Table 1. Information on raw materials used in the examples and comparative examples.

[0080] Example 1 This embodiment prepares a niobium carbide-ethylene-butyl rubber liquid phase composite material and uses it to prepare rubber sealing products. The steps are as follows: Preparation of niobium carbide and ethylene-butyl rubber liquid phase composite material: S11. Select niobium carbide raw material with a purity of 99% and a particle size of 2-4μm, mix it with 95% ethanol aqueous solution at a solid-liquid ratio of 1g: 8mL, and stir continuously at a stirring speed of 400r / min for 25min to initially form a uniform suspension. S12. Add sodium dodecylbenzenesulfonate at 1% of the mass of niobium carbide to the suspension, and continue stirring at 400 r / min for 15 min. Then place the suspension in an ultrasonic device and sonicate at 400 W for 1.5 h. Centrifuge the resulting suspension at 6000 r / min for 15 min, collect the solid product and dry it at 90 °C for 5 h to obtain niobium carbide nanofillers with a particle size of 20-40 nm. S13. Niobium carbide nanofiller, PEG-400 and water are mixed at a mass ratio of 1:0.02:15 and stirred at 500 r / min for 25 min to form a niobium carbide dispersion; ethylene butyl rubber, fatty alcohol polyoxyethylene ether and water are mixed at a mass ratio of 1:0.02:15 and stirred at 400 r / min for 35 min to form an ethylene butyl rubber dispersion. S21. Inject the niobium carbide dispersion into the ethylene butyl rubber dispersion at a rate of 5 mL / min, and add the silane coupling agent KH-550. Then, stir at 200 r / min for 15 min, and then stir at 500 r / min for 35 min to obtain a mixture. The content of niobium carbide nanofiller is 1% of the mass of ethylene butyl rubber, and the amount of KH-550 is 2% of the mass of the ethylene butyl rubber solution dispersion. S31. Add flocculant PAM to the mixture at a dosage of 1% of the mixture mass, continue stirring for 20 min, and then let stand for 1 h to allow the mixture to flocculate; after flocculation, filter with filter paper, collect the solid phase and dry at 70℃ for 10 h to obtain the composite material precursor. S41. Place the composite material precursor in a two-roll mill. Set the two-roll mill temperature to 60℃ and the roll gap to 0.8mm. Press the mixture into sheets at a speed of 25r / min. After pressing, let the rubber sheet rest for 12-24h to allow the internal stress to be fully released and the molecular chains to rearrange, thus obtaining a niobium carbide and ethylene-butyl rubber liquid phase composite material, namely F-1. Preparation of rubber sealing products: 1) Preheat the open mill to 70℃, adjust the roll gap to 1.5mm, and keep the roll speed ratio at 1: (1.3-1.4). Add 101g of niobium carbide and ethylene butadiene rubber liquid phase composite material F-1 to the open mill, adjust the roll gap to make the rubber completely wrap the rolls to form a smooth roll-wrapped rubber, and adjust the rubber accumulation to 10-15g to keep a small amount of rubber accumulated between the rolls. 2) Dry 30 parts of N550 carbon black and 35 parts of N774 carbon black in an oven at 100℃ for 2 hours. Then add half of the N550 carbon black and N774 carbon black, and 1 part of internal release agent 935P. After they are basically dispersed, add the remaining N550 carbon black and N774 carbon black, and 1 part of internal release agent 935P until all fillers are completely and evenly dispersed. 3) Add 5 parts zinc oxide and 1 part stearic acid, and mix until uniform; add 1 part antioxidant MB and 1 part antioxidant 445, and mix for 3 minutes; finally add 2.5 parts DCP and 1 part TAIC, control the roller temperature to not exceed 80℃, and mix for 5 minutes to ensure dispersion. 4) Adjust the roller gap to 2mm, pass the rubber compound through the thin layer 3 times, and make a triangular wrap 3 times after each thin layer. Finally, adjust the roller gap to 5mm and cut the sheet to obtain a compounded rubber sheet with a thickness of about 5mm. Let it stand at room temperature (23±2℃) for 24 hours. 5) The mixed rubber sheet is vulcanized on a flat vulcanizing machine at 160℃ and 15MPa for 20 minutes. After the vulcanization is completed, it is left to stand at room temperature for 24 hours to obtain a rubber sealing product, which is denoted as Y-1.

[0081] Example 2 This embodiment prepares a niobium carbide and ethylene butyl rubber liquid phase composite material and uses it to prepare rubber sealing products. The only difference from Example 1 is that in the niobium carbide and ethylene butyl rubber liquid phase composite material, the content of niobium carbide nanofiller is 2% of the mass of ethylene butyl rubber, denoted as F-1, and the rubber sealing product prepared by F-2 is denoted as Y-2.

[0082] Example 3 This embodiment prepares a niobium carbide and ethylene butyl rubber liquid phase composite material and uses it to prepare rubber sealing products. The only difference from Example 1 is that in the niobium carbide and ethylene butyl rubber liquid phase composite material, the content of niobium carbide nanofiller is 3% of the mass of ethylene butyl rubber, denoted as F-3. The rubber sealing product prepared with F-3 is denoted as Y-3.

[0083] Example 4 This embodiment prepares a niobium carbide and ethylene butyl rubber liquid phase composite material and uses it to prepare rubber sealing products. The only difference from Example 1 is that in the niobium carbide and ethylene butyl rubber liquid phase composite material, the content of niobium carbide nanofiller is 4% of the mass of ethylene butyl rubber, denoted as F-4. The rubber sealing product prepared with F-4 is denoted as Y-4.

[0084] Example 5 This embodiment prepares a niobium carbide and ethylene butyl rubber liquid phase composite material and uses it to prepare rubber sealing products. The only difference from Example 1 is that in the niobium carbide and ethylene butyl rubber liquid phase composite material, the content of niobium carbide nanofiller is 5% of the mass of ethylene butyl rubber, denoted as F-5. The rubber sealing product prepared with F-5 is denoted as Y-5.

[0085] Comparative Example 1 This comparative example prepares a rubber sealing product, and the steps are as follows: 1) Preheat the open mill to 70℃, adjust the roll gap to 1.5mm, and keep the roll speed ratio at 1: (1.3-1.4). Add 101g of niobium carbide and ethylene butadiene rubber liquid phase composite material F-1 to the open mill, adjust the roll gap to make the rubber completely wrap the rolls to form a smooth roll-wrapped rubber, and adjust the rubber accumulation to 10-15g to keep a small amount of rubber accumulated between the rolls. 2) Dry 3 parts of niobium carbide powder with a particle size of 20-40nm, 30 parts of N550 carbon black and 35 parts of N774 carbon black in an oven at 100℃ for 2h. Then add the niobium carbide powder in batches until it is completely and evenly dispersed. Then add half of the N550 carbon black and N774 carbon black and 1 part of internal release agent 935P. After it is basically dispersed, add the remaining N550 carbon black and N774 carbon black and 1 part of internal release agent 935P until all fillers are completely and evenly dispersed. 3) Add 5 parts zinc oxide and 1 part stearic acid, and mix until uniform; add 1 part antioxidant MB and 1 part antioxidant 445, and mix for 3 minutes; finally add 2.5 parts DCP and 1 part TAIC, control the roller temperature to not exceed 80℃, and mix for 5 minutes to ensure dispersion. 4) Adjust the roller gap to 2mm, pass the rubber compound through the thin layer 3 times, and make a triangular wrap 3 times after each thin layer. Finally, adjust the roller gap to 5mm and cut the sheet to obtain a compounded rubber sheet with a thickness of about 5mm. Let it stand at room temperature (23±2℃) for 24 hours. 5) The mixed rubber sheet is vulcanized on a flat vulcanizing machine at 160℃ and 15MPa for 20 minutes. After the vulcanization is completed, it is left to stand at room temperature for 24 hours to obtain a rubber sealing product, which is denoted as G-1.

[0086] Comparative Example 2 This comparative example prepares a rubber sealing product, and the steps are as follows: 1) Preheat the open mill to 70℃, adjust the roll gap to 1.5mm, and keep the roll speed ratio at 1: (1.3-1.4). Add 101g of niobium carbide and ethylene butadiene rubber liquid phase composite material F-1 to the open mill, adjust the roll gap to make the rubber completely wrap the rolls to form a smooth roll-wrapped rubber, and adjust the rubber accumulation to 10-15g to keep a small amount of rubber accumulated between the rolls. 2) Dry 30 parts of N550 carbon black and 35 parts of N774 carbon black in an oven at 100℃ for 2 hours. Then, add half of the N550 carbon black and N774 carbon black, as well as 1 part of internal release agent 935P. After they are basically dispersed, add the remaining N550 carbon black and N774 carbon black, as well as 1 part of internal release agent 935P, until all fillers are completely and evenly dispersed. 3) Add 5 parts zinc oxide and 1 part stearic acid, and mix until uniform; add 1 part antioxidant MB and 1 part antioxidant 445, and mix for 3 minutes; finally add 2.5 parts DCP and 1 part TAIC, control the roller temperature to not exceed 80℃, and mix for 5 minutes to ensure dispersion. 4) Adjust the roller gap to 2mm, pass the rubber compound through the thin layer 3 times, and make a triangular wrap 3 times after each thin layer. Finally, adjust the roller gap to 5mm and cut the sheet to obtain a compounded rubber sheet with a thickness of about 5mm. Let it stand at room temperature (23±2℃) for 24 hours. 5) The mixed rubber sheet is vulcanized on a flat vulcanizing machine at 160℃ and 15MPa for 20 minutes. After the vulcanization is completed, it is left to stand at room temperature for 24 hours to obtain a rubber sealing product, which is denoted as W-1.

[0087] Performance testing The performance of the rubber sealing products prepared in Examples 1-5 and Comparative Examples 1-2 was tested. The test items and reference standards are as follows: 1. Shore hardness: Tested according to GB / T 531.1-2008 "Vulcanized rubber or thermoplastic rubber - Indentation hardness test method - Part 1: Shore hardness tester method (Shore hardness)"; 2. Tensile strength and elongation at break: Tested in accordance with GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber"; 3. Permanent deformation rate (Permanent Deformation Rate I) after hot air aging at 125℃ for 168 hours with a compression rate of 25% and after hot air aging at 150℃ for 168 hours with a compression rate of 25% (Permanent Deformation Rate II): The tests were conducted in accordance with GB / T 7759.1-2015 "Determination of Compression Permanence of Vulcanized Rubber or Thermoplastic Rubber - Part 1: Under Normal and High Temperature Conditions".

[0088] Table 2 Performance test results of rubber sealing products in Examples 1-5 and Comparative Examples 1-2

[0089] Table 2 shows the performance test results of the rubber sealing products in Examples 1-5 and Comparative Examples 1-2. Y-1 to Y-5 are sealing products made from composite materials (F-1 to F-5) prepared by the liquid phase method, with niobium carbide content increasing from 1% (relative to ethylene butyl rubber) to 5%. G-1 is a comparative sample made by traditional dry mixing with the direct addition of 3 parts of micron-sized niobium carbide. W-1 is a pure ethylene butyl rubber base formulation without any added niobium carbide, serving as the performance comparison benchmark. As shown in Table 2, the tensile strength of Y-3 (16.1 MPa) is approximately 33% higher than that of G-1 (12.1 MPa), and the elongation at break (313%) is approximately 65% ​​higher than that of G-1 (190%). This fully demonstrates the nanoscale dispersion and strong interface achieved by the liquid phase method. The combination transforms niobium carbide from a stress concentration defect point (dry process) into a highly efficient load-bearing reinforcement point, while significantly improving the strength and toughness of the material. The compression set of Y-3 after aging at 125℃ and 150℃ (17% and 32%) is significantly lower than that of G-1 (29% and 45%), indicating that the uniformly dispersed nano-niobium carbide network and strong interface can more effectively suppress the irreversible slippage of rubber molecular chains at high temperatures, resulting in better thermal stability. The hardness of G-1 (74) is abnormally high, which is a typical characteristic of severe agglomeration of micron-sized fillers, resulting in a hard and brittle material. The hardness of Y-3 (69) is moderate, reflecting the balance between reinforcement and elasticity. It can be seen that the liquid phase composite process fundamentally solves the problems of filler agglomeration and weak interface in dry mixing, which is the key to the leap in performance.

[0090] Among Y-1 to Y-5, tensile strength and elongation at break both peaked at Y-3 (3% content) (16.1 MPa, 313%), and then began to decline in Y-4 and Y-5. This indicates that at this addition amount, the nanofiller dispersion reached an ideal state, forming an effective stress transfer network. Exceeding this amount, the filler spacing became too small, and even in the liquid phase, local agglomeration easily occurred, becoming defect points again, leading to a decline in performance. The lowest compression set at 125℃ occurred in Y-3 (17%), and at 150℃, Y- 3 (32%) also performed best, indicating that an appropriate amount of uniformly dispersed nano-niobium carbide provided the greatest thermal shielding and network constraint effect. Insufficient amount would not have a good effect, while excessive amount would cause internal defects due to agglomeration, weakening the network stability. As for hardness, the hardness increased slowly with the increase of niobium carbide content, which is consistent with the general rule that the rubber becomes harder with the increase of filler. Therefore, in the liquid phase composite material of niobium carbide and ethylene butyl rubber, the content of niobium carbide nanofiller is 3% of the mass of ethylene butyl rubber, which is the best ratio to achieve a balance of strength, toughness and heat resistance.

[0091] Compared to W-1 without niobium carbide, Y-3, which has the best performance, shows significant improvements in tensile strength (8% increase), elongation at break (6% increase), and heat-resistant compression deformation at 125℃ (15% reduction). Furthermore, W-1 outperforms G-1 by the dry method in all aspects, with higher strength, higher elongation, and less deformation. This demonstrates that using the wrong process (dry method) to add niobium carbide can have even negative effects, highlighting the necessity of the liquid phase composite process.

Claims

1. A niobium carbide and ethylene-butyl rubber liquid-phase composite material, characterized in that, The invention comprises an ethylene-butyl rubber matrix and niobium carbide nanofillers dispersed in the matrix; wherein the niobium carbide nanofillers are chemically bonded to the molecular chains of the ethylene-butyl rubber via a coupling agent, and their content is 1%-5% of the mass of the ethylene-butyl rubber.

2. The niobium carbide and ethylene-butyl rubber liquid-phase composite material according to claim 1, characterized in that, The niobium carbide nanofiller is prepared by a method comprising the following steps: dispersing micron-sized niobium carbide in an alcohol solution, adding an anionic surfactant, and ultrasonically treating the solution to obtain the niobium carbide nanofiller with a particle size of 20-40 nm.

3. The niobium carbide and ethylene-butyl rubber liquid-phase composite material according to claim 2, characterized in that, The prepared niobium carbide nanofiller has an alcohol solution volume concentration of 85%-95%; the solid-liquid ratio of the micron-sized niobium carbide to the alcohol solution is 1g: (5-10)mL. And / or, the amount of the anionic surfactant is 0.5%-2% of the mass of micron-sized niobium carbide; And / or, the ultrasonic treatment power is 300-500W, and the time is 1-2h.

4. The niobium carbide and ethylene-butyl rubber liquid-phase composite material according to any one of claims 1-3, characterized in that, The niobium carbide and ethylene butyl rubber liquid phase composite material comprises the following raw materials: ethylene butyl rubber, niobium carbide nanofiller, coupling agent, nonionic surfactant, flocculant and water.

5. The method for preparing the niobium carbide and ethylene-butyl rubber liquid-phase composite material according to claim 4, characterized in that, Includes the following steps: S1. Niobium carbide nanofiller, nonionic surfactant and water are mixed to obtain niobium carbide dispersion; ethylene butyl rubber, nonionic surfactant and water are mixed to obtain ethylene butyl rubber dispersion. S2. Inject the niobium carbide dispersion into the ethylene butyl rubber dispersion, add a coupling agent, react, and obtain a mixture. S3. Add flocculant to the mixture to obtain composite material precursor; S4. The composite material precursor is pressed into sheets to obtain the niobium carbide and ethylene butyl rubber liquid phase composite material.

6. The method for preparing the niobium carbide and ethylene-butyl rubber liquid-phase composite material according to claim 5, characterized in that, The mass ratio of the niobium carbide nanofiller, nonionic surfactant, and water is 1: (0.01-0.03): (10-20); And / or, the mass ratio of the ethylene butyl rubber, nonionic surfactant, and water is 1: (0.01-0.03): (10-20); And / or, the amount of the coupling agent is 1%-3% of the mass of the ethylene butyl rubber solution dispersion; And / or, the amount of the flocculant used is 0.5%-2% of the mass of the mixture; And / or, the temperature for tableting is 50-70°C.

7. A rubber sealing product, characterized in that, The preparation materials, by weight, include the following raw materials: 100-105 parts of niobium carbide and ethylene-butyl rubber liquid phase composite material, 55-75 parts of reinforcing filler, 1-3 parts of silane coupling agent, 3.5-5 parts of peroxide vulcanization system, and 1-5 parts of antioxidant; wherein the niobium carbide and ethylene-butyl rubber liquid phase composite material is as described in any one of claims 1-3.

8. The rubber sealing product according to claim 7, characterized in that, The reinforcing filler includes at least one of medium-high structure carbon black and large particle size low structure carbon black. And / or, the peroxide vulcanization system includes a peroxide vulcanizing agent and a crosslinking agent; And / or, the antioxidant includes at least one of imidazole antioxidants and amine antioxidants.

9. The method for preparing the rubber sealing product according to claim 7 or 8, characterized in that, Includes the following steps: The raw materials for preparing the rubber sealing product are mixed together to obtain a compound rubber. The compounded rubber is vulcanized to obtain the rubber sealing product.

10. The application of the rubber sealing product according to claim 7 or 8 in electrical equipment.

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