Air filter element, preparation method and application

Abstract

The invention provides an air filter element, a preparation method and application, the air filter element is provided with a plurality of filter layers, the plurality of filter layers comprise a first filter layer, a hydrophobic layer, a second filter layer and a flow guide layer which are connected in sequence, the hydrophobic layer comprises a nano microporous hydrophobic film and hydrophobic modified porous particles, and the hydrophobic modified porous particles are arranged in the first filter layer. The hydrophobic modified porous particles are attached to the surface of the nano-microporous hydrophobic film, the pore diameter of the nano-microporous hydrophobic film of the hydrophobic layer is 0.1-0.8 mu m, and the particle size of the hydrophobic modified porous particles is 100-200 meshes. According to the filter element structure in the scheme, the filter precision and the air inlet efficiency are guaranteed, and meanwhile the technical problem that in the prior art, an engine air inlet system is poor in waterproof performance when a vehicle wades into water is solved.

Description

Technical Field

[0001] This invention relates to the technical field of air filter elements, and more specifically, to an air filter element, its preparation method, and its application. Background Technology

[0002] Traditional car air filters are mostly made of non-woven fabric, filter paper, and other materials. Their main function is limited to intercepting dust and particulate matter in the air, lacking effective waterproof and breathable performance. When a car is wading through water at a depth close to or exceeding the height of the air intake, liquid water and water vapor are highly likely to enter the engine, causing a series of problems, including but not limited to: piston seizure, cylinder corrosion, and engine stalling. These problems not only endanger driving safety but also lead to high repair costs, seriously affecting user experience and vehicle lifespan.

[0003] To improve their cars' wading performance, some owners choose to modify their snorkels, redesigning the vehicle's air intake system to raise the air intake above the wading depth to prevent direct water intrusion. This modification is costly, has poor compatibility, and may affect the vehicle's original performance. Some waterproof air filters use a hydrophobic coating to prevent liquid water intrusion, but these filters generally have limited waterproofing, especially in blocking water vapor. Furthermore, the coating is prone to peeling off under high temperatures and airflow, affecting the filter's waterproofing performance and lifespan, while also increasing intake resistance and reducing engine power output.

[0004] There is currently no effective solution to the technical problem of poor waterproof performance of the engine intake system when a vehicle is wading through water. Summary of the Invention

[0005] The main objective of this invention is to provide an air filter element, its preparation method, and its application, in order to solve the technical problem of poor waterproof performance of the engine intake system when a vehicle is wading through water.

[0006] To achieve the above objectives, according to one aspect of the present invention, an air filter element is provided, the air filter element having multiple filter layers, the multiple filter layers including a first filter layer, a hydrophobic layer, a second filter layer and a flow guiding layer connected in sequence, the hydrophobic layer including a nanoporous hydrophobic membrane and hydrophobically modified porous particles, the hydrophobically modified porous particles being attached to the surface of the nanoporous hydrophobic membrane, wherein the pore size of the nanoporous hydrophobic membrane is 0.1~0.8μm and the particle size of the hydrophobic modified porous particles is 100~200 mesh.

[0007] Furthermore, the hydrophobically modified porous particles include at least one of MOF particles modified with silane coupling agent, carbon molecular sieve and zeolite molecular sieve, and the water contact angle of the hydrophobically modified porous particles is α, where α ≥ 150°.

[0008] Furthermore, the first filter layer is made of polyester needle-punched nonwoven fabric with a pore size of 100~150μm and an areal density of 90~120g / m³. 2 .

[0009] Furthermore, the second filter layer is made of glass fiber and wood pulp fiber, the filtration accuracy of the second filter layer is 2~5μm, and the porosity of the second filter layer is β1, β1≥75%.

[0010] Furthermore, the flow guiding layer is made of honeycomb polypropylene sheet with a pore size of 4~6mm and a porosity of β2, where β2≥85%.

[0011] According to another aspect of the present invention, a method for preparing an air filter element is provided, comprising the following steps: adding porous particles to an ethanol solution containing a silane coupling agent for modification treatment to obtain hydrophobically modified porous particles; diluting a first binder with an ethyl acetate solution, adding the hydrophobically modified porous particles to the diluted first binder and stirring to obtain a coating slurry; coating the coating slurry onto the surfaces of both sides of a nanoporous hydrophobic membrane and performing a curing treatment to obtain a hydrophobic layer; placing a first filter layer, a hydrophobic layer, a second filter layer, and a flow guiding layer in a predetermined sequence, with a second binder coated between two adjacent filter layers, and performing hot pressing and curing treatment to obtain a filter element substrate; cutting and punching the filter element substrate according to the size of the air filter, and assembling a sealing ring at the edge of the filter element substrate to obtain an air filter element.

[0012] Further, the porous particles are modified by adding an ethanol solution containing a silane coupling agent, including the following steps: after adding the porous particles to the ethanol solution containing the silane coupling agent, the particles are stirred and modified at an ambient temperature of 80~120℃ and a stirring speed of 400r / min for 1~3h to obtain hydrophobic modified porous particles; the hydrophobic modified porous particles are washed with anhydrous ethanol and dried; the dried hydrophobic modified porous particles are then subjected to a mesh sieve treatment.

[0013] Furthermore, the first adhesive includes at least one of fluorosilicone rubber, silicone rubber, and phenolic resin, and / or the second adhesive includes at least one of fluorosilicone rubber, silicone rubber, and phenolic resin.

[0014] Furthermore, in the hydrophobic layer, the mass percentage of the first binder is 3-7%.

[0015] According to another aspect of the present invention, an application of an air filter element is provided, wherein the aforementioned air filter element is applied to an air filter of a vehicle engine.

[0016] The air filter element, using the technical solution of this invention, is composed of a first filter layer, a hydrophobic layer, a second filter layer, and a flow-guiding layer. The first filter layer performs preliminary filtration of impurities in the air, the hydrophobic layer filters water from the air, the second filter layer performs deep filtration of impurities in the air, and the flow-guiding layer guides airflow to uniformly penetrate the filter element. The multiple filter layers work synergistically to achieve waterproofing, filtration, and low-resistance functions. The hydrophobic layer is composed of a nanoporous hydrophobic membrane and hydrophobically modified porous particles. The nanoporous hydrophobic membrane with a pore size of 0.1~0.8μm ensures the free passage of air molecules while effectively blocking the penetration of liquid water molecules. The hydrophobically modified porous particles with a particle size of 100~200 mesh enhance the filter element's ability to intercept tiny water droplets and water vapor. This dual waterproof design solves the problem of poor waterproofing in traditional filter elements, effectively preventing piston seizure, cylinder corrosion, and other safety issues related to driving in water. The filter element structure in the above solution, while ensuring filtration accuracy and intake efficiency, solves the technical problem of poor waterproofing performance of the engine intake system in existing technologies when vehicles are wading through water. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0018] Figure 1 A schematic diagram of the air filter element in this application is shown;

[0019] Figure 2 The manufacturing process of the air filter element in this application is shown.

[0020] The above figures include the following reference numerals:

[0021] 1. First filter layer;

[0022] 2. Hydrophobic layer;

[0023] 3. Second filter layer;

[0024] 4. Flow deflector layer;

[0025] 5. Adhesive layer;

[0026] 6. Sealing ring. Detailed Implementation

[0027] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0028] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0029] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0030] Exemplary embodiments according to this application will now be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of this application is thorough and complete, and that the concept of these exemplary embodiments is fully conveyed to those skilled in the art. In the drawings, for clarity, the thickness of layers and regions may be exaggerated, and the same reference numerals are used to denote the same devices, and therefore their description will be omitted.

[0031] Combination Figure 1 As shown, according to a specific embodiment of this application, an air filter element is provided.

[0032] Specifically, the air filter element has multiple filter layers, which include a first filter layer 1, a hydrophobic layer 2, a second filter layer 3, and a flow guiding layer 4 connected in sequence. The hydrophobic layer 2 includes a nanoporous hydrophobic membrane and hydrophobically modified porous particles. The hydrophobically modified porous particles are attached to the surface of the nanoporous hydrophobic membrane. The pore size of the nanoporous hydrophobic membrane in the hydrophobic layer 2 is 0.1~0.8μm, and the particle size of the hydrophobic modified porous particles is 100~200 mesh.

[0033] In the embodiments of this application, the air filter element is composed of a first filter layer 1, a hydrophobic layer 2, a second filter layer 3, and a flow guiding layer 4. The first filter layer 1 performs preliminary filtration of impurities in the air, the hydrophobic layer 2 is used to filter water in the air, the second filter layer 3 performs deep filtration of impurities in the air, and the flow guiding layer 4 is used to guide airflow to penetrate the filter element evenly. The multiple filter layers work together to achieve waterproof, filtration, and low-resistance functions. The hydrophobic layer 2 is composed of a nanoporous hydrophobic membrane and hydrophobically modified porous particles. The nanoporous hydrophobic membrane with a pore size of 0.1~0.8μm can ensure that air molecules can pass freely while effectively blocking the penetration of liquid water molecules. The hydrophobically modified porous particles with a particle size of 100~200 mesh enhance the filter element's ability to intercept tiny water droplets and water vapor. This dual waterproof design solves the problem of poor waterproof performance of traditional filter elements and effectively prevents water-related driving safety problems such as piston seizure and cylinder corrosion. The filter structure in the above solution, while ensuring filtration accuracy and air intake efficiency, solves the technical problem of poor waterproof performance of the engine air intake system when the vehicle is wading through water in the prior art.

[0034] Furthermore, the hydrophobically modified porous particles include at least one of MOF particles modified with silane coupling agent, carbon molecular sieve and zeolite molecular sieve, and the water contact angle of the hydrophobically modified porous particles is α, where α ≥ 150°.

[0035] The MOF particles are ZIF-8 or ZIF-67.

[0036] In the embodiments of this application, MOF particles, carbon molecular sieves, and zeolite molecular sieves have regular microporous structures, which can achieve sieving of different gas molecules, maintain low intake resistance, and ensure that the engine power output is not affected. Through silane coupling agent modification, the hydrophilic groups on the surface of MOF particles, carbon molecular sieves, and zeolite molecular sieves are replaced by hydrophobic methyl groups, forming a stable superhydrophobic surface. Furthermore, the water contact angle α of the hydrophobically modified porous particles is ≥150°, which effectively repels water molecules. Even tiny water droplets or water vapor are difficult to form sufficient contact on the particle surface, ensuring that the filter element can maintain stable waterproof performance under continuous water immersion conditions.

[0037] Furthermore, the first filter layer 1 is made of polyester needle-punched nonwoven fabric with a pore size of 100~150μm and an areal density of 90~120g / m³. 2 .

[0038] In the embodiments of this application, during the initial stage of air entering the filter element, the polyester needle-punched nonwoven fabric intercepts impurities such as sand and large dust particles in the air, providing protection for subsequent filtration and the hydrophobic layer 2. The pore size of the polyester needle-punched nonwoven fabric is set between 100 and 150 μm, ensuring effective interception of large particles without excessively hindering airflow, thus guaranteeing the overall air permeability of the air filter element and reducing air intake resistance. The areal density of the polyester needle-punched nonwoven fabric is 90-120 g / m³. 2 While ensuring sufficient air permeability of polyester needle-punched nonwoven fabric, the mechanical strength of the material is enhanced, so that it can maintain the integrity of the structure when facing complex working conditions such as airflow impact and temperature changes, thus avoiding deformation or damage of the filter layer during long-term use.

[0039] Furthermore, the second filter layer 3 is made of glass fiber and wood pulp fiber, the filtration accuracy of the second filter layer 3 is 2~5μm, and the porosity of the second filter layer 3 is β1, β1≥75%.

[0040] In the embodiments of this application, the second filter layer 3 is a composite filter paper of glass fiber and wood pulp fiber. Glass fiber has excellent high-temperature resistance and chemical stability, preventing the filter layer from deforming under airflow impact, while wood pulp fiber has good hygroscopicity and softness, which helps to absorb the small vibrations caused by airflow fluctuations inside the filter layer and maintain the flatness of the filter layer. The two fibers are combined in a specific ratio to form the second filter layer 3, which can effectively filter out fine particles with a particle size between 2 and 5 μm in the air, such as PM2.5 and other pollutants, ensuring the air quality inhaled by the engine. Compared with the first filter layer 1, the second filter layer 3 provides a higher level of filtration, ensuring the cleanliness of the engine interior and extending the engine's service life. The porosity of the second filter layer 3 is β1≥75%. The high porosity ensures that most of the airflow can pass smoothly, reducing the resistance of the air filter element to the intake system and avoiding affecting the engine's power output. The high porosity also promotes uniform pressure distribution within the filter layer, avoiding localized airflow congestion and ensuring that the airflow is evenly distributed throughout the entire filter layer.

[0041] Furthermore, the flow guiding layer 4 is made of honeycomb polypropylene sheet with a pore size of 4~6mm and a porosity of β2, where β2≥85%.

[0042] In the embodiments of this application, the pore size of the flow guiding layer 4 is 4~6mm, which ensures that the airflow can be effectively dispersed when passing through, avoiding excessively fast local airflow speed or the formation of eddies; the design of the porosity β2≥85% of the flow guiding layer 4 enhances the uniformity of airflow, enabling the airflow to smoothly and quickly penetrate the entire filter element and reducing the air intake resistance; that is, the pore size and porosity design of the honeycomb polypropylene plate can effectively guide the airflow to penetrate the entire filter element, ensuring smooth airflow even after high-density filter materials, and avoiding the decrease in filter element efficiency caused by airflow obstruction.

[0043] The multiple filter layers include a first filter layer 1, a hydrophobic layer 2, a second filter layer 3, and a flow guiding layer 4 connected in sequence. The hydrophobic layer 2 includes a nanoporous hydrophobic membrane and hydrophobically modified porous particles. The hydrophobically modified porous particles are attached to the surface of the nanoporous hydrophobic membrane. The pore size of the nanoporous hydrophobic membrane in the hydrophobic layer 2 is 0.1~0.8μm, and the particle size of the hydrophobic modified porous particles is 100~200 mesh.

[0044] According to another specific embodiment of this application, a method for preparing an air filter element is provided, such as... Figure 2 As shown, it includes the following steps:

[0045] Step S1: The porous particles are added to an ethanol solution containing a silane coupling agent for modification treatment to obtain hydrophobically modified porous particles.

[0046] Specifically, the porous particles are ZIF-8, and the silane coupling agent is methyltrimethoxysilane or KH-570.

[0047] The porous particles are modified by using an ethanol solution containing a silane coupling agent. Through chemical bonding, hydrophobic groups are effectively grafted onto the surface of the porous particles, thereby obtaining hydrophobically modified porous particles with a high water contact angle. This step ensures that the hydrophobic layer 2 of the air filter can efficiently intercept liquid water and water vapor, achieving a perfect combination of air permeability and moisture blocking, and solving the main problem faced by the engine intake system when the vehicle is wading through water.

[0048] Step S2: Dilute the first binder with ethyl acetate solution, add the hydrophobic modified porous particles to the diluted first binder and stir to obtain the coating slurry.

[0049] Step S3: Coat the coating slurry onto the surfaces of both sides of the nanoporous hydrophobic film and cure it to obtain hydrophobic layer 2.

[0050] Specifically, a coating slurry is uniformly coated onto both sides of the nanoporous hydrophobic membrane using a spraying method, with a coating thickness of 0.15~0.35mm on each side. After pre-curing at 100~140℃ for 30 minutes, hydrophobic layer 2 is obtained. The temperature resistance range of hydrophobic layer 2 is -40℃~150℃, making it suitable for the extreme temperature environments of engine intake systems and ensuring stable performance of the filter element under both extremely cold and high temperature conditions. The thickness of hydrophobic layer 2 is controlled between 0.3~0.7mm.

[0051] Step S4: Place the first filter layer 1, the hydrophobic layer 2, the second filter layer 3 and the flow guiding layer 4 in a preset order, and coat the two adjacent filter layers with a second adhesive. Perform hot pressing and curing treatment to obtain the filter element substrate.

[0052] Specifically, the first filter layer 1, the hydrophobic layer 2, the second filter layer 3, and the flow guiding layer 4 are placed into a hot rolling mill in a preset order, the temperature is set to 100~140℃, the pressure is set to 0.4Mpa, and the pressing time is 8min; after pressing, the layers are cured in a constant temperature oven at 100~140℃ for 30~60min to achieve a firm composite of each layer.

[0053] The second adhesive applied between the two filter layers forms an adhesive layer 5.

[0054] The slurry preparation, coating, curing, and multi-layer hot-pressing curing processes in steps S2 to S4 effectively promote the tight bonding between the various material layers. The mixing of the first binder with hydrophobically modified porous particles not only improves the stability of the hydrophobic layer 2 material itself but also ensures its good bonding with the nanoporous hydrophobic membrane. The second binder further enhances the interlayer bonding between the first filter layer 1, the hydrophobic layer 2, the second filter layer 3, and the flow guiding layer 4. Even under the strong airflow impact generated by engine operation, the material layers will not peel off or shift, ensuring the structural stability and functional consistency of the air filter element under complex operating conditions.

[0055] Step S5: Cut and punch holes in the filter element substrate according to the size of the air filter, and install sealing rings 6 on the edge of the filter element substrate to obtain the air filter.

[0056] The sealing ring 6 fitted at the edge of the filter element substrate ensures a tight fit between the filter element and the filter housing, preventing air leakage and improving the installation quality and waterproof effect of the filter element.

[0057] Furthermore, the porous particles are modified by adding them to an ethanol solution containing a silane coupling agent, including the following steps:

[0058] Step S11: After adding the porous particles to an ethanol solution containing a silane coupling agent, the particles are stirred and modified at an ambient temperature of 80~120℃ and a stirring speed of 400r / min for 1~3h to obtain hydrophobically modified porous particles.

[0059] The modification treatment is carried out within a temperature range of 80~120℃ to promote the effective reaction between the silane coupling agent and the surface of the porous particles. The relatively high but not overheated ambient temperature accelerates the formation of chemical bonds, allowing hydrophobic groups to be more firmly grafted onto the porous particles, thereby improving the modification efficiency. A stirring speed of 400 r / min ensures uniform suspension of the porous particles in the solution, avoiding the problem of incomplete local reactions, while a modification time of 1~3 hours provides a sufficient time window to complete the modification reaction, ensuring the quality of the hydrophobically modified porous particles.

[0060] Specifically, porous granular raw powder is added to a silane coupling agent ethanol solution with a mass fraction of 8%~10%, and the solid-liquid ratio is 1:8.

[0061] Step S12: Wash the hydrophobic modified porous particles with anhydrous ethanol and then dry them.

[0062] Specifically, the particles are dried at 110°C for 2 hours. Step S12 aims to remove residual ethanol solvent and byproducts from the modification process, and also cleans away any impurities that may be adsorbed on the surface of the porous particles, further improving the purity of the hydrophobically modified porous particles.

[0063] Step S13: Perform mesh sieving on the dried hydrophobic modified porous particles.

[0064] Specifically, a 100-200 mesh sieve is used for sieving. Screening the dried hydrophobic modified porous particles removes particles that do not meet the particle size requirements, which is beneficial for the uniform dispersion of the subsequent coating and maximizing the hydrophobic efficiency.

[0065] The modification treatment of porous particles by steps S11 to S13 not only significantly improves the hydrophobic properties of the particles and ensures the quality of the hydrophobically modified porous particles, but also provides uniform and pure raw materials for subsequent composite material design.

[0066] Furthermore, the first adhesive includes at least one of fluorosilicone rubber, silicone rubber, and phenolic resin, and / or the second adhesive includes at least one of fluorosilicone rubber, silicone rubber, and phenolic resin.

[0067] Fluorosilicone rubber, silicone rubber, and phenolic resin all possess excellent weather resistance and a wide operating temperature range. Fluorosilicone rubber and silicone rubber remain stable within a temperature range of -40℃ to 150℃, while phenolic resin exhibits excellent mechanical strength and chemical resistance at high temperatures. This temperature resistance ensures that the adhesive layer 5 of the air filter will not soften, decompose, or lose its adhesiveness under various climatic conditions and in the high-temperature operating environment of the engine, thus maintaining a strong bond between the various material layers and improving the overall durability and reliability of the filter element. All three materials demonstrate good chemical stability and anti-aging properties. In the complex chemical environment inside the air filter element, whether it is oil, exhaust gas, or changes in humidity, the adhesive layer 5 can resist chemical erosion and maintain the stability of its physical properties.

[0068] Furthermore, in the hydrophobic layer 2, the mass percentage of the first adhesive is 3-7%.

[0069] An appropriate amount of adhesive can ensure the strength of the interlayer bond while avoiding excessive pore clogging, thereby reducing the resistance of the filter element when air passes through and maintaining good intake performance of the engine.

[0070] Example 1

[0071] For example, the first filter layer 1 is a polyester needle-punched nonwoven fabric with a pore size of 120 μm and an areal density of 100 g / m³. 2 The first layer has a thickness of 1.2 mm. The second layer has a thickness of 0.5 mm and is composed of PTFE nanoporous film (pore size 0.5 μm) and ZIF-8 particles (particle size 150 mesh) modified with methyltrimethoxysilane. The modification temperature is 100℃, the modification time is 2 h, and the water contact angle after modification is 155°. The third layer is a composite filter paper of glass fiber and wood pulp fiber, with a filtration accuracy of 3 μm, a porosity of 78%, and a thickness of 1.0 mm. The fourth layer is a honeycomb polypropylene board with a honeycomb pore size of 5 mm, a porosity of 86%, and a thickness of 1.2 mm. The binder is fluorosilicone rubber, accounting for 5% of the mass of the fourth layer, with a curing temperature of 120℃, a curing time of 45 min, and a temperature resistance range of -40℃ to 150℃. The sealing ring 6 is nitrile rubber with a width of 1.5 mm. The specific preparation process is as follows:

[0072] (1) Preparation of hydrophobically modified ZIF-8 particles: ZIF-8 raw powder was added to a 9% (w / w) methyltrimethoxysilane ethanol solution with a solid-liquid ratio of 1:8. The mixture was stirred and modified at 100℃ and 400r / min for 2h. After being washed three times with anhydrous ethanol, it was dried at 110℃ for 2h and passed through a 150-mesh sieve for later use.

[0073] (2) Preparation of hydrophobic layer 2: Fluorosilicone rubber was diluted with ethyl acetate to a mass fraction of 5%, and hydrophobic modified ZIF-8 particles were added and stirred to form a slurry. The slurry was uniformly coated on both sides of the PTFE nanoporous film by spraying, with a coating thickness of 0.25 mm on each side. The slurry was pre-cured at 120℃ for 30 min to obtain hydrophobic layer 2.

[0074] (3) Multilayer composite: The first filter layer 1, the hydrophobic layer 2 (coated surface facing the first filter layer 1), the second filter layer 3, and the flow guiding layer 4 are stacked in sequence, placed in a hot rolling mill, pressed at 120℃ and 0.4MPa pressure for 8 minutes, and then cured in a constant temperature oven at 120℃ for 45 minutes to achieve a firm composite of each layer;

[0075] (4) Finished product processing: According to the size of the air filter of a 2.0L car, the composite plate is trimmed and punched, and nitrile rubber sealing ring 6 is assembled to obtain the finished air filter element.

[0076] According to actual measurements, in the embodiments of this application, the hydrophobic efficiency of the air filter element is ≥99.5% (i.e., no water penetration after immersion in 15~20cm deep clean water for 30min); when the gas flow rate is 20m / s, the air intake resistance of the air filter element is only 4~7kPa, which is better than that of traditional filter elements (6~8kPa); the filtration efficiency for particles with a diameter ≥3μm is ≥99%, which meets the air intake cleanliness requirements of automobiles, and the service life can reach 10000-12000km.

[0077] According to another specific embodiment of this application, an application of an air filter element is provided, wherein the air filter element in the above embodiment is applied to the air filter of a vehicle engine.

[0078] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0079] In addition to the above, it should be noted that the terms "one embodiment," "another embodiment," and "embodiment" used in this specification refer to specific features, structures, or characteristics described in connection with that embodiment, which are included in at least one embodiment described in the general description of this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in connection with any embodiment, the intention is to suggest that implementing such a feature, structure, or characteristic in conjunction with other embodiments also falls within the scope of this invention.

[0080] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0081] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An air filter element, characterized in that, The air filter element is provided with multiple filter layers, which include a first filter layer (1), a hydrophobic layer (2), a second filter layer (3), and a flow guiding layer (4) connected in sequence. The hydrophobic layer (2) includes a nanoporous hydrophobic film and hydrophobic modified porous particles. The hydrophobic modified porous particles are attached to the surface of the nanoporous hydrophobic film. The pore size of the nanoporous hydrophobic film in the hydrophobic layer (2) is 0.1~0.8μm, and the particle size of the hydrophobic modified porous particles is 100~200 mesh.

2. The air filter element according to claim 1, characterized in that, The hydrophobically modified porous particles include at least one of MOF particles modified with a silane coupling agent, carbon molecular sieves, and zeolite molecular sieves, and the water contact angle of the hydrophobically modified porous particles is α, where α ≥ 150°.

3. The air filter element according to claim 1, characterized in that, The first filter layer (1) is made of polyester needle-punched nonwoven fabric with a pore size of 100~150μm and a surface density of 90~120g / m³. 2 .

4. The air filter element according to claim 1, characterized in that, The second filter layer (3) is made of glass fiber and wood pulp fiber. The filtration accuracy of the second filter layer (3) is 2~5μ. The porosity of the second filter layer (3) is β1, β1≥75%.

5. The air filter element according to claim 1, characterized in that, The flow guide layer (4) is made of honeycomb polypropylene plate with a pore size of 4~6mm and a porosity of β2, β2≥85%.

6. A method for preparing an air filter element, characterized in that, Includes the following steps: Porous particles were modified by adding them to an ethanol solution containing a silane coupling agent to obtain hydrophobically modified porous particles. The first binder was diluted with ethyl acetate solution, and the hydrophobic modified porous particles were added to the diluted first binder and stirred to obtain a coating slurry. The coating slurry is coated on both sides of the nanoporous hydrophobic film and then cured to obtain a hydrophobic layer (2). The first filter layer (1), the hydrophobic layer (2), the second filter layer (3) and the flow guiding layer (4) are placed in a preset order, and a second adhesive is applied between two adjacent filter layers. The filter is then subjected to hot pressing and curing to obtain the filter element substrate. According to the size of the air filter, the filter element substrate is cut and punched, and a sealing ring (6) is assembled on the edge of the filter element substrate to obtain the air filter.

7. The preparation method according to claim 6, characterized in that, The porous particles are modified by adding them to an ethanol solution containing a silane coupling agent, including the following steps: After the porous particles are added to an ethanol solution containing a silane coupling agent, they are stirred and modified at an ambient temperature of 80~120℃ and a stirring speed of 400r / min for 1~3h to obtain hydrophobically modified porous particles. The hydrophobic modified porous particles were washed with anhydrous ethanol and then dried. The dried hydrophobic modified porous particles were subjected to a mesh sieve treatment.

8. The preparation method according to claim 6, characterized in that, The first adhesive comprises at least one of fluorosilicone rubber, silicone rubber and phenolic resin, and / or the second adhesive comprises at least one of fluorosilicone rubber, silicone rubber and phenolic resin.

9. The preparation method according to claim 6, characterized in that, In the hydrophobic layer (2), the mass percentage of the first adhesive is 3-7%.

10. An application of an air filter element, characterized in that, The air filter element described in any one of claims 1-5 is used in the air filter of a vehicle engine.

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