A fuel filter element and a method of making and using the same

Abstract

The application discloses a fuel filter filter material and a preparation method and application thereof, and relates to the technical field of composite filter materials.The fuel filter filter material comprises a first filter layer, a second filter layer and a third filter layer which are sequentially stacked, wherein raw material components of the first filter layer comprise polybutylene terephthalate and a conductive agent; raw material components of the second filter layer comprise glass fiber, polybutylene terephthalate fiber, conductive fiber and auxiliary fiber; and raw material components of the third filter layer comprise polybutylene terephthalate and an antibacterial agent.The fuel filter filter material provided by the application can solve the technical problems of poor acid corrosion resistance, low oil-water separation efficiency, insufficient filtration precision, easy static electricity accumulation, easy breeding of microorganisms and short service life of the filter material for biodiesel in the prior art.

Description

Technical Field

[0001] This invention relates to the field of composite filter material technology, specifically to a fuel filter material, its preparation method, and its application. Background Technology

[0002] Biodiesel, as a renewable and environmentally friendly new clean energy source, has been widely promoted and applied globally in recent years. Compared with traditional petroleum-based diesel, biodiesel has advantages such as lower sulfur content, better lubrication performance, and biodegradability. However, during the production, storage, and transportation of biodiesel, due to the influence of its raw material sources (such as animal and vegetable oils) and transesterification characteristics, it often contains a higher proportion of water, acidic substances, gums, and impurities. In addition, biodiesel has strong hygroscopicity and is prone to oxidation and deterioration during use.

[0003] Fuel filters are a critical component of the engine's fuel system. Their main function is to filter out solid impurities such as iron oxide and dust, as well as moisture, from the fuel to prevent clogging of the fuel system (especially the fuel injectors), reduce mechanical wear, and ensure stable engine operation. Currently, most existing fuel filter media use a single-layer structure, and the materials are mostly ordinary cellulose paper or conventional polyester (PET) nonwoven fabric. However, when these traditional filter media are applied to biodiesel filtration applications, the following significant technical shortcomings are exposed: First, it lacks resistance to chemical corrosion. The acidic substances and moisture in biodiesel can accelerate the hydrolysis and corrosion of ordinary filter media, leading to a decrease in the strength of the filter media, damage, and even filtration failure, thus shortening the service life of the filter.

[0004] Secondly, there is the safety hazard of static electricity buildup. When biodiesel flows through the filter media, the high-speed flow and friction easily generate static electricity. Traditional filter media are mostly insulating materials, lacking effective conductive paths, causing static charges to accumulate inside the filter. When the static voltage reaches a certain level, it may generate electric sparks, posing a safety risk of fire or explosion under certain conditions.

[0005] Secondly, microbial growth leads to clogging. The moisture and organic components in biodiesel provide a suitable environment for the growth of microorganisms (such as bacteria and fungi). Microorganisms multiply on the surface of the filter media and form a biofilm, which is not only difficult to remove through conventional filtration, but also further adsorbs impurities, causing the filter to clog quickly and increasing maintenance costs.

[0006] Finally, filtration accuracy and dust holding capacity are difficult to balance. Existing single-layer filter media structures often struggle to achieve both filtration accuracy and dust holding capacity. If high filtration accuracy is pursued, the porosity is low, the dust holding capacity is small, and it is prone to clogging; if high dust holding capacity is pursued, the filtration accuracy is insufficient, and tiny particles can easily penetrate the filter media and enter the engine system, causing wear.

[0007] Therefore, how to develop a fuel filter material that combines high air permeability, high filtration efficiency, and high dust holding capacity to adapt to the special operating environment of biodiesel has become an urgent technical problem to be solved in the field of fuel filtration technology. Summary of the Invention

[0008] This invention provides a fuel filter material, its preparation method, and its application to solve the technical problems of insufficient filtration accuracy, low dust holding capacity, and low air permeability of biodiesel filter materials in related technologies.

[0009] In a first aspect, the present invention provides a fuel filter media, the fuel filter media comprising a first filter layer, a second filter layer, and a third filter layer stacked sequentially, wherein... The raw material components of the first filter layer include polybutylene terephthalate and a conductive agent; The raw material components of the second filter layer include glass fiber, polybutylene terephthalate fiber, conductive fiber, and auxiliary fiber; The raw material components of the third filter layer include polybutylene terephthalate and antibacterial agents.

[0010] In some embodiments, the conductive agent accounts for 0.5%-3% of the total mass of the first filter layer.

[0011] In some embodiments, the conductive agent is selected from at least one of conductive carbon black, carbon nanotubes, and graphene materials.

[0012] In some embodiments, the intrinsic viscosity of the polybutylene terephthalate in the first filter layer is 0.75 dL / g to 0.85 dL / g.

[0013] In some embodiments, in the second filter layer, the mass fraction of glass fiber is 40%-45%, the mass fraction of polybutylene terephthalate fiber is 50%-55%, the mass fraction of conductive fiber is 3%-5%, and the mass fraction of auxiliary fiber is 1%-7%.

[0014] In some embodiments, the conductive fiber includes carbon fiber.

[0015] In some embodiments, the auxiliary fiber is selected from at least one of acrylic fiber, PET fiber, basalt fiber, PTFE fiber and spandex fiber.

[0016] In some embodiments, the antibacterial agent accounts for 0.8%-1.5% of the total mass of the third filter layer.

[0017] In some embodiments, the antimicrobial agent comprises a silver ion-loaded antimicrobial agent on a metal-organic framework material.

[0018] In some embodiments, the metal-organic framework material is selected from one of UiO-66-NH2, UiO-66, NH2-MIL-125(Ti), MIL-101(Cr) and ZIF-8.

[0019] In some embodiments, the intrinsic viscosity of the polybutylene terephthalate is 0.65 dL / g to 0.75 dL / g.

[0020] In some embodiments, the weight ratio of the first filter layer, the second filter layer and the third filter layer is (50-75):(130-180):(45-65).

[0021] In some embodiments, the thickness of the fuel filter media is 1.0 mm to 1.35 mm.

[0022] In some embodiments, the fuel filter media has a gradient filtration structure, wherein the first filter layer is used to filter particulate matter with a particle size greater than 10 μm, the second filter layer is used to filter particulate matter with a particle size of 4-10 μm, and the third filter layer is used to filter particulate matter with a particle size less than 4 μm.

[0023] In a second aspect, the present invention provides a method for preparing the fuel filter material described in the first aspect, comprising the following steps: The first filter layer is obtained by blending a conductive agent with polybutylene terephthalate and then processing it by melt-blowing. The second filter layer is prepared by mixing glass fiber, polybutylene terephthalate fiber, conductive fiber and auxiliary fiber, followed by pulping, molding and drying. The third filter layer is prepared by blending antibacterial agent with polybutylene terephthalate and then using a melt-blowing process. The first filter layer, the second filter layer, and the third filter layer are hot-pressed to form the fuel filter media.

[0024] In some embodiments, during the step of preparing the first filter layer, the hot air pressure of the meltblown process is 15-25 kPa and the hot air temperature is 260-290°C.

[0025] In some embodiments, during the step of preparing the third filter layer, the hot air pressure of the meltblown process is 25-40 kPa and the hot air temperature is 220-230°C.

[0026] In some embodiments, the temperature for point hot pressing is 205°C-225°C.

[0027] Thirdly, the present invention provides a fuel filter comprising the fuel filter media described in the first aspect.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. By compounding conductive carbon materials and conductive fibers into the filter media, a continuous conductive path is constructed, which can quickly eliminate the static electricity accumulation caused by the friction of biodiesel flow, eliminate the safety risks caused by static sparks, and significantly improve the safety of use.

[0029] 2. The metal-organic framework material is used to load silver ion antibacterial agents, so as to achieve controlled slow release of silver ions and synergistic sterilization of "silver ions + active oxygen", which effectively inhibits the growth of microorganisms and the formation of biofilm, avoids the rapid clogging of the filter element due to microbial contamination, and greatly extends the service life.

[0030] 3. A gradient pore structure is formed by an outer polybutylene terephthalate (PBT) conductive layer, a middle glass fiber / PBT fiber hybrid layer, and an inner ultrafine fiber layer. Impurities are intercepted in a graded manner according to >10μm, 4-10μm, and <4μm, which greatly improves dust holding capacity and reduces flow resistance while ensuring high filtration accuracy.

[0031] 4. The filter material is bonded by hot pressing with a point-type hot press, which is simple and has a strong interlayer bond. The filter material can be directly folded and formed into a cylindrical filter element. It is resistant to the acid corrosion of biodiesel, has good oil-water separation effect, and has excellent comprehensive performance. It is especially suitable for biodiesel-specific filters. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the fuel filter media structure provided in an embodiment of the present invention.

[0034] Reference numerals: Fuel filter media 100, first filter layer 10, second filter layer 20, third filter layer 30, adhesive layer 40. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0036] The inventors discovered that by employing a three-layer composite gradient pore structure, using acid-resistant polybutylene terephthalate (PBT) as the substrate, and introducing conductive materials in the outer layer, conductive fibers in the middle layer, and metal-organic frameworks (MOFs) loaded with silver ion antibacterial agents in the inner layer, it is possible to simultaneously achieve acid resistance, antistatic properties, antibacterial properties, high-precision graded filtration, high dust holding capacity, low flow resistance, and efficient oil-water separation, making it perfectly suited for biodiesel application scenarios.

[0037] In view of this, the present invention provides a fuel filter material, its preparation method and application, to solve the technical problems of insufficient filtration accuracy, low dust holding capacity and low air permeability of biodiesel filter materials in related technologies.

[0038] In a first aspect, the present invention provides a fuel filter media, according to embodiments of the present invention, such as... Figure 1 As shown, the fuel filter media 100 includes a first filter layer 10, a second filter layer 20, and a third filter layer 30 stacked sequentially, wherein... The raw material components of the first filter layer 10 include polybutylene terephthalate and a conductive agent; The raw material components of the second filter layer 20 include glass fiber, polybutylene terephthalate fiber, conductive fiber and auxiliary fiber; The raw material components of the third filter layer 30 include polybutylene terephthalate and an antibacterial agent.

[0039] This invention employs a three-layer composite structure stacked sequentially. Leveraging the excellent hydrolysis and acid corrosion resistance of the PBT substrate, it effectively resists the erosion of acidic substances and moisture in biodiesel. Simultaneously, the conductive agent in the first filter layer and the conductive fibers in the second filter layer work together to construct a continuous conductive network throughout the filter media, promptly dissipating static electricity buildup caused by fuel flow and eliminating safety hazards. The antibacterial agent added to the third filter layer inhibits microbial growth, preventing filter clogging caused by biofilm formation. Meanwhile, the glass fibers in the second filter layer provide structural support, ensuring the strength of the filter media. This achieves a comprehensive performance profile, including high filtration accuracy, high dust holding capacity, high air permeability, and structural stability, thereby extending the service life of the fuel filter.

[0040] It should be noted that the present invention does not impose any special limitation on the form of PBT, and it can include, but is not limited to, conventional raw material forms in the art such as slices, granules, flakes, and columns. Those skilled in the art can flexibly choose according to actual processing needs. According to a specific embodiment of the present invention, the PBT is PBT slices.

[0041] In some embodiments of the present invention, the conductive agent accounts for 0.5%-3% of the total mass of the first filter layer. Within this range, the conductive agent content reaches the permeation threshold, enabling the first filter layer to possess antistatic properties, promptly dissipating the static charge generated by the flow of biodiesel, and preventing the danger caused by electric sparks. At the same time, this addition amount avoids the decrease in the processing performance of the matrix material and the increase in cost caused by excessive conductive agent, ensuring the structural stability of the first filter layer and achieving a balance between antistatic effect, processing performance, and economy.

[0042] In some embodiments of the present invention, the conductive agent is selected from at least one of conductive carbon black, carbon nanotubes, and graphene. By selecting the above-mentioned conductive agents, and utilizing the conductivity and chemical stability of these carbon-based conductive materials, conductive pathways can be efficiently constructed in the PBT matrix. Carbon nanotubes and graphene have high aspect ratios, which helps to form a complete conductive network, while conductive carbon black has good dispersibility. These materials are all resistant to biodiesel corrosion and have stable performance in fuel environments, ensuring that the first filter layer can effectively and persistently remove electrostatic charges generated by fuel flow, preventing static electricity accumulation that could lead to safety hazards, while maintaining good mechanical properties, thus improving the safety of the fuel filter.

[0043] In some embodiments of the present invention, the intrinsic viscosity of the polybutylene terephthalate (PBT) in the first filter layer is 0.75 dL / g to 0.85 dL / g. By limiting the intrinsic viscosity of PBT in the first filter layer to the above range, the PBT melt has suitable fluidity and melt strength. In the subsequent melt-blowing process, this viscosity range ensures that the PBT melt can be easily stretched into fine fibers by hot air, avoiding processing difficulties or excessively coarse fibers due to excessive viscosity, while also preventing problems such as insufficient melt strength, easy fiber breakage, or poor web uniformity due to excessively low viscosity. Therefore, the resulting first filter layer has excellent mechanical strength and structural stability, effectively supporting the conductive agent and resisting the erosion of biodiesel, while maintaining the inherent acid corrosion resistance of PBT material, ensuring the reliability of the filter material during long-term use.

[0044] It should be noted that the intrinsic viscosity mentioned in this invention refers to the intrinsic viscosity of a 0.5 g / dL dilute PBT solution prepared with phenol-tetrachloroethane (mass ratio 1:1) as solvent, measured using an Ubbelohde viscometer at 25°C. The unit is dL / g, and it is used to characterize the molecular weight and melt flow properties of PBT resin.

[0045] In some embodiments of the present invention, in the second filter layer, the mass fraction of the glass fiber is 40%-45%, the mass fraction of the polybutylene terephthalate fiber is 50%-55%, the mass fraction of the conductive fiber is 3%-5%, and the mass fraction of the auxiliary fiber is 1%-7%.

[0046] This invention ensures excellent mechanical strength and structural stability of the filter media by limiting the mass fraction of glass fiber in the second filter layer to 40%-45% and the mass fraction of PBT fiber to 50%-55%, forming a robust framework that resists the impact of fuel flow. The mass fraction of conductive fiber is limited to 3%-5%, ensuring a continuous conductive network within the mixed fiber matrix to synergistically dissipate static electricity with the first filter layer, while avoiding increased cost and brittleness due to excessive addition. The mass fraction of auxiliary fibers is limited to 1%-7% to adjust the flexibility and pore structure of the filter media. This specific component ratio achieves a second filter layer that provides strong support while possessing high-efficiency antistatic properties and good processing adaptability, thereby guaranteeing the overall service life and safety performance of the fuel filter media.

[0047] In some embodiments of the present invention, the conductive fiber comprises carbon fiber. Utilizing the excellent conductivity and chemical stability of carbon fiber, conductive pathways can be efficiently constructed within the glass fiber matrix of the second filter layer. Carbon fiber not only synergizes with the conductive agent in the first filter layer to form a continuous conductive network throughout the filter media, promptly dissipating electrostatic charges generated by the flow of biodiesel and eliminating safety hazards, but also possesses high strength and resistance to acid and alkali corrosion, enabling it to adapt to the harsh environment of biodiesel and preventing conductivity failure due to corrosion or breakage during long-term use. This ensures the durability and reliability of the antistatic properties of the fuel filter media.

[0048] In some embodiments of the present invention, the auxiliary fiber is selected from at least one of acrylic fiber, PET fiber, basalt fiber, PTFE fiber and spandex fiber.

[0049] This invention modifies and optimizes the second filter layer by selecting at least one auxiliary fiber from acrylic fiber, PET fiber, basalt fiber, PTFE fiber, and spandex fiber, utilizing the specific physicochemical properties of these materials. PTFE fiber provides excellent chemical corrosion resistance, enabling it to withstand the acidic environment of biodiesel; basalt fiber enhances the heat resistance and strength of the filter media; while acrylic fiber, spandex fiber, and PET fiber effectively improve the brittleness of the glass fiber matrix, enhancing the flexibility and impact resistance of the filter media. This specific material selection optimizes the pore structure and mechanical properties of the fiber network without significantly reducing the overall corrosion resistance of the filter media, ensuring the structural stability and filtration reliability of the second filter layer under complex operating conditions, thereby guaranteeing the long-term reliable operation of the fuel filter.

[0050] In some embodiments of the present invention, the antibacterial agent accounts for 0.8%-1.5% of the total mass of the third filter layer. Within this mass percentage range, the antibacterial performance threshold is met without causing deterioration of PBT melt flowability or a decrease in fiber breaking strength.

[0051] In some embodiments of the present invention, the antibacterial agent comprises silver ions (Ag) supported on a metal-organic framework material. + Antibacterial agent.

[0052] This invention utilizes metal-organic frameworks (MOFs) to load silver ion antibacterial agents. The highly ordered microporous structure (approximately 1-3 nm) of MOFs anchors silver ions, preventing their aggregation. In a biodiesel environment, a diffusion control mechanism enables the controlled, sustained release of silver ions, avoiding burst release and improving safety, achieving long-lasting antibacterial effects (>99.9% inhibition rate maintained for over 30 days). Simultaneously, the excellent thermal stability of MOFs ensures structural integrity at PBT melt processing temperatures (220℃-230°C). Surface modification improves compatibility and dispersion uniformity with the matrix without affecting mechanical strength or filtration efficiency. Furthermore, the metal-organic framework exhibits peroxidase-like activity, synergistically bactericidally interacting with silver ions to construct a dual antibacterial mechanism of "silver ions + reactive oxygen species," which enhances antibacterial durability, broad spectrum, and material lifespan.

[0053] In some embodiments of the present invention, the MOFs are selected from one of UiO-66-NH2, UiO-66, NH2-MIL-125(Ti), MIL-101(Cr) and ZIF-8.

[0054] This invention ensures that the carrier material possesses excellent thermal and chemical stability by limiting the MOFs to one of UiO-66-NH2, UiO-66, NH2-MIL-125(Ti), MIL-101(Cr), and ZIF-8. This allows the MOFs to withstand the high-temperature environment of PBT melting without decomposition, maintaining structural integrity for precise anchoring of silver ions. These specific types of MOF materials have suitable pore structures, which are beneficial for the loading and controlled release of silver ions, avoiding initial burst release failure. They also exhibit good tolerance in biodiesel environments, continuously exerting a synergistic bactericidal effect of "silver ions + active oxygen," thereby ensuring that the inner filter material maintains efficient and stable antibacterial performance throughout its long service life and effectively preventing filter clogging caused by microbial growth.

[0055] In some embodiments of the present invention, the intrinsic viscosity of the polybutylene terephthalate in the third filter layer is 0.65 dL / g-0.75 dL / g.

[0056] This invention limits the intrinsic viscosity of PBT in the third filter layer to 0.65 dL / g-0.75 dL / g, resulting in a resin melt with low melt viscosity and suitable fluidity. This facilitates full stretching by high-temperature, high-speed hot air during the melt-blowing process, leading to the formation of ultrafine fiber structures with finer diameters (0.5-10 μm). This viscosity range avoids the problems of excessively high viscosity leading to coarse fibers and reduced filtration accuracy, while preventing defects such as insufficient melt strength, fiber breakage, or uneven web formation caused by excessively low viscosity. Consequently, the resulting third filter layer not only has a higher specific surface area, improving the contact efficiency and antibacterial effect between the antimicrobial agent and fuel, but also ensures that the filter media maintains good structural integrity while possessing high filtration accuracy, effectively intercepting fine particles and preventing microbial clogging.

[0057] In some embodiments of the present invention, the weight ratio of the first filter layer, the second filter layer, and the third filter layer is (50-75):(130-180):(45-65). The present invention optimizes the quality configuration of each functional layer of the filter media by limiting the weight distribution of the first, second, and third filter layers to (50-75):(130-180):(45-65). The second filter layer has a higher weight, providing excellent mechanical strength and dust-holding capacity as the main support layer, ensuring the structural stability of the filter media under fuel impact. The first and third filter layers maintain a suitable low weight, ensuring effective loading and coverage of conductive and antibacterial functional components while avoiding excessive filtration resistance due to excessively thick surface layers. This specific weight distribution balances the structural strength, filtration performance, and fuel flow capacity of the filter media, enabling it to have sufficient mechanical support while possessing a low initial pressure drop and a high dirt-holding capacity, thereby effectively extending the service life of the fuel filter.

[0058] It should be explained that the basis weight ratio mentioned in this invention refers to the ratio of the unit area mass (basis weight, unit: g / m²) of the first filter layer, the second filter layer, and the third filter layer. It is used to limit the material ratio and structural distribution of the three filter media to ensure that the overall filtration performance, mechanical strength, air permeability resistance and structural stability of the filter media reach the optimal balance.

[0059] In some embodiments of the present invention, the thickness of the fuel filter media is 1.0-1.35 mm.

[0060] This invention limits the thickness of the fuel filter media to 1.0mm-1.35mm. A thickness of at least 1.0mm ensures sufficient pore volume and dust-holding space, preventing rapid clogging due to insufficient dirt-holding capacity caused by an excessively thin filter layer. A thickness of at least 1.35mm effectively controls the flow resistance of fuel, preventing excessive fuel supply pressure loss due to excessively thick filter media, while also accommodating the installation space of the filter housing. This specific thickness design, while ensuring that the first, second, and third filter layers fully utilize their conductive, supportive, and antibacterial functions, balances the relationship between filtration accuracy, dust holding capacity, and fuel flow performance. It also prevents performance degradation of the filter media due to compression deformation during long-term use, thereby extending the maintenance cycle and service life of the fuel filter.

[0061] In some embodiments of the present invention, the fuel filter media is a gradient filtration structure, wherein the first filter layer is used to filter particulate matter with a particle size greater than 10 μm, the second filter layer is used to filter particulate matter with a particle size of 4-10 μm, and the third filter layer is used to filter particulate matter with a particle size less than 4 μm.

[0062] This invention sets the fuel filter media to a gradient filtration structure. The first filter layer intercepts large particulate impurities larger than 10μm, the second filter layer intercepts medium particulate impurities of 4-10μm, and the third filter layer intercepts micro-particulate impurities smaller than 4μm. This achieves graded filtration from coarse to fine, which can efficiently remove fine pollutants such as unsaponifiable fatty acids, colloids, and microbial metabolites from biodiesel. This helps to improve filtration accuracy and dust holding capacity, reduce flow resistance, and effectively prevent fine impurities from clogging precision injectors. It is suitable for the high impurity and fine particle size filtration requirements of biodiesel and better meets the requirements of biodiesel-specific filters for high-precision filtration and long-term stable use.

[0063] In some embodiments of the present invention, such as Figure 1 As shown, the first filter layer 10, the second filter layer 20 and the third filter layer 30 are bonded and fixed together by an adhesive layer 40.

[0064] This invention achieves integrated composite of three filter layers by setting an adhesive layer 40 between the first filter layer 10, the second filter layer 20, and the third filter layer 30. This adhesive layer effectively prevents the filter media from delamination, misalignment, or deformation under fuel flow impact and engine vibration, ensuring the stability of the conductive contact between the first and second filter layers, thereby maintaining the connectivity of the conductive network throughout the filter media. Simultaneously, the strong interlayer bonding strength ensures the positional stability of the gradient filtration structure during long-term use, avoiding a decrease in filtration accuracy or functional failure due to interlayer separation. This ensures the consistency and reliability of the overall structure of the fuel filter media, thereby ensuring that the fuel filter maintains stable filtration, antistatic, and antibacterial performance during long-term use.

[0065] In some embodiments of the present invention, the adhesive layer 40 includes a PBT fiber layer. At 205℃-225℃, the multi-layer filter material is composited using a point-pressing method, causing slight melting of the surface layers of adjacent PBT fiber layers. After cooling, the molten areas form purely physical bonding points, thus forming an adhesive layer between the layers. These bonding points account for only 3-8% of the total area, with a porosity loss of <5%. The entire process involves no adhesives or chemical additives, achieving stable composite of the multi-layer filter material. Furthermore, this PBT fiber layer possesses characteristics of resistance to biodiesel corrosion and high bonding strength, enabling the three filter layers to be firmly composited into one, preventing delamination and detachment during use. It also does not clog the micropores of the filter material or obstruct fuel flow. While achieving stable composite of the three-layer structure, it fully preserves the gradient pore size, high air permeability, and low flow resistance characteristics of the filter material.

[0066] Secondly, the present invention provides a method for preparing the fuel filter material, wherein, according to an embodiment of the present invention, the preparation method includes the following steps: S100. The conductive agent is blended with polybutylene terephthalate and the first filter layer is obtained by melt-blowing process.

[0067] This step involves blending the conductive agent with PBT and then using a melt-blown process to form the first filter layer. This allows the conductive agent to be uniformly dispersed in the PBT substrate, forming a continuous and stable conductive path. This effectively eliminates the static electricity buildup generated during the flow of biodiesel, avoiding safety risks caused by static sparks. At the same time, the melt-blown process gives the filter layer a uniform fiber structure and suitable pore size, ensuring good filtration and air permeability of the first filter layer. Furthermore, the acid corrosion resistance of PBT makes it suitable for the acidic environment of biodiesel use, improving the overall stability and service life of the filter layer.

[0068] In some embodiments of the present invention, in the step of preparing the first filter layer, the hot air pressure of the meltblown process is 15-25 kPa, and the hot air temperature is 260-290°C. This temperature range ensures that the PBT melt is fully plasticized and has a suitable viscosity, facilitating effective stretching into fibers under high-temperature hot air, while avoiding excessive temperature that could lead to resin degradation or damage to the conductive agent structure. Combined with the 15-25 kPa air pressure, it provides appropriate stretching force, resulting in a uniform fiber diameter distribution and promoting the axial orientation of the conductive agent along the fiber axis, thereby constructing a stable conductive network. Thus, the resulting first filter layer not only possesses excellent antistatic properties and mechanical strength but also maintains a suitable pore structure, ensuring the stability and reliability of the first filter layer's filtration function.

[0069] S200: Glass fiber, PBT fiber, conductive fiber and auxiliary fiber are mixed, and the mixture is pulped, molded and dried to obtain the second filter layer.

[0070] This step involves mixing glass fiber, PBT fiber, conductive fiber, and auxiliary fibers, followed by pulping, molding, and drying to obtain the second filter layer. This allows various fibers to interweave evenly, forming a structurally stable fiber mesh carrier. While ensuring efficient filtration of medium-sized impurities, it further enhances the overall structural strength and dust holding capacity of the filter material. Combined with conductive fibers, it achieves a synergistic antistatic effect, preventing the accumulation of static electricity during biodiesel flow. Furthermore, the wet molding process allows for more uniform fiber distribution, ensuring that the air permeability and flow resistance of the filter layer match the usage requirements of biodiesel filters.

[0071] S300: The antibacterial agent is blended with polybutylene terephthalate and the third filter layer is obtained by melt-blowing process.

[0072] In this step, the third filter layer is prepared by blending the antibacterial agent with PBT and using a melt-blowing process. The high-temperature, high-speed stretching effect of the melt-blowing process uniformly loads and encapsulates the antibacterial agent within the PBT microfiber matrix, effectively preventing rapid loss or agglomeration and deactivation of the antibacterial agent under fuel scouring. The blending process ensures uniform dispersion of the antibacterial components in the filter layer, resulting in consistent antibacterial capabilities. The microfiber structure formed by melt-blowing has a high specific surface area, increasing the contact efficiency between the antibacterial agent and microorganisms, enhancing the bactericidal effect, and creating fine pores for high-precision filtration. Furthermore, the third filter layer prepared by this process combines the acid corrosion resistance and structural stability of PBT material, enabling it to maintain stable antibacterial and precision filtration functions for a long time even in the harsh environment of biodiesel, effectively preventing filter clogging caused by microbial growth and extending the filter's service life.

[0073] In some embodiments of the present invention, the fiber diameter formed in the third filter layer is 0.5μm-10μm. Limiting the fiber diameter of the third filter layer to the above range can form a uniform and dense ultrafine fiber network, making the average pore size of the filter layer micropores stable at about 3μm. This can accurately intercept impurities such as fine colloids and microbial metabolites smaller than 4μm in biodiesel, achieving high-precision filtration, while ensuring suitable air permeability and low flow resistance. At the same time, it provides sufficient attachment sites for antibacterial agents, allowing silver ions to be released in a controlled manner and fully contact the bacteria, enhancing the long-lasting antibacterial effect. Furthermore, the dense fiber structure can effectively improve oil-water separation efficiency, meeting the high-precision and long-life requirements of biodiesel-specific filters.

[0074] It should be noted that the fiber diameter mentioned in this invention refers to the average cross-sectional diameter of a single meltblown ultrafine fiber in the third filter layer, which is obtained by observation and statistical calculation using a scanning electron microscope (SEM), and the unit is μm.

[0075] In some embodiments of the present invention, in the step of preparing the third filter layer, the hot air pressure of the melt-blowing process is 25-40 kPa, and the hot air temperature is 220-230°C. This temperature range is slightly lower than the processing temperature of the first filter layer, which ensures that the PBT melt flows appropriately to be stretched into ultrafine fibers of 0.5-10 μm, while avoiding excessively high temperatures that could lead to the decomposition or inactivation of the antibacterial agent or structural damage. Combined with the relatively high air pressure of 25-40 kPa, sufficient stretching force is provided to refine the fibers, forming a dense microporous structure to improve filtration accuracy. Therefore, the resulting third filter layer not only has high-precision filtration capability but also ensures the effective loading and long-term release of the antibacterial agent, achieving a balance between antibacterial and filtration performance, and effectively preventing filter clogging caused by microbial growth.

[0076] S400. Point-type hot pressing is used between the first filter layer, the second filter layer and the third filter layer to obtain the fuel filter material.

[0077] In this step, the three layers of PBT-based material are integrated and composited directly through hot pressing without the need for adhesives between the first, second, and third filter layers. The molten PBT fibers form a strong bonding interface between the layers, effectively preventing delamination, misalignment, or deformation of the filter media under fuel flow impact and engine vibration, ensuring the conductivity of the conductive network and the stability of the gradient filtration structure. The hot pressing process not only controls the overall thickness and pore structure of the composite filter media but also enhances the interlayer bonding strength, enabling it to withstand subsequent folding and rolling processes without failure. This step simplifies the composite process, ensures the consistency and reliability of the filter media structure, and thus ensures that the fuel filter maintains stable filtration, antistatic, and antibacterial performance during long-term use.

[0078] In some embodiments of the present invention, the hot-pressing temperature is 205℃-225℃. This temperature range allows the surface PBT fibers to melt and microflow, ensuring a strong bonding interface between the three filter layers and preventing the filter media from delaminating or shifting under fuel impact. Simultaneously, this temperature is slightly lower than the melting point of the PBT matrix fibers, preventing the fiber skeleton from shrinking, deforming, or the pore structure from collapsing due to overheating, thus maintaining the stability of the gradient filtration structure. Furthermore, the suitable temperature effectively avoids potential thermal damage to the active ingredients of the antibacterial agent and the conductive network structure, ensuring that the filter media maintains excellent antibacterial and conductive properties after composite molding. This guarantees the overall structural integrity and functional reliability of the fuel filter media, extending its service life.

[0079] Thirdly, the present invention provides a fuel filter, wherein, according to an embodiment of the present invention, the fuel filter employs the fuel filter material described in the first aspect above.

[0080] The fuel filter provided by this invention, by employing the aforementioned three-layer composite fuel filter media, inherits the excellent acid corrosion resistance, antistatic properties, and antibacterial properties of the filter media, making it particularly suitable for biodiesel filtration applications. This fuel filter effectively resists the erosion of acidic substances and moisture in the fuel, prevents safety hazards caused by static electricity buildup, and inhibits filter element clogging caused by microbial growth, extending the filter's maintenance cycle and service life. Simultaneously, thanks to the gradient filtration structure of the filter media, this fuel filter maintains high filtration accuracy while possessing high oil flow capacity, effectively protecting the engine's fuel system from wear caused by impurities, and ensuring the long-term stable operation and reliability of the power system.

[0081] The technical solution provided by the present invention will be described in detail below with reference to the embodiments.

[0082] The raw materials used in the embodiments and comparative examples of this invention are as follows: Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this invention are all commercially available conventional products.

[0083] Example 1 This embodiment 1 provides a fuel filter material, the preparation method of which is as follows: 1) Preparation of the first filter layer: PBT chips with an intrinsic viscosity of 0.75 dL / g were dried, and carbon nanotubes with a mass fraction of 1% were added and mixed evenly. After being melt-extruded by an extruder and metered by a metering pump, the fibers were spun and melt-blown. The fibers were drawn and stretched into fibers under hot air pressure of 25 kPa and hot air temperature of 260℃, cooled, and wound to obtain the melt-blown outer layer material. The basis weight of this layer was 50 g / m² and the thickness was 0.3 mm.

[0084] 2) Preparation of the second filter layer: By mass fraction, 40 parts glass fiber, 50 parts PBT fiber, 5 parts carbon fiber, and 5 parts spandex fiber are mixed evenly, and then diluted, pulped, wound, slit, and dried to obtain the intermediate layer filter material; the basis weight of this layer is 170 g / m², and the thickness is 0.60 mm.

[0085] 3) Preparation of the third filter layer: (1) Disperse UiO-66-NH2 in a 0.1 mol / L aqueous solution of AgNO3, stir until homogeneous, centrifuge, wash, and spray dry at 80°C to obtain the MOFs-supported silver ion antibacterial agent Ag. + @UiO-66-NH2; (2) PBT chips with an intrinsic viscosity of 0.65 dL / g and Ag with a mass fraction of 1.5% were mixed. + @UiO-66-NH2 was mixed evenly and granulated to prepare antibacterial polyester masterbatch; the antibacterial polyester masterbatch was further blended with PBT chips to reduce Ag content in the system. + The mass fraction of @UiO-66-NH2 is 0.8%. After being melt-extruded by an extruder and metered by a metering pump, it is spun into melt-blown fibers. Under the conditions of hot air pressure of 30 kPa and hot air temperature of 220℃, it is stretched into fibers, cooled, and wound to obtain the melt-blown inner layer material. The basis weight of this layer is 50 g / m², and the thickness is 0.25 mm.

[0086] 4) Three-layer filter media composite molding: The first filter layer, the second filter layer, and the third filter layer are laid flat in sequence and fixed by point hot pressing at 205°C. After cooling and rolling, the filter material roll is obtained, which is the filter material of this embodiment. The total weight is 270g / m² and the thickness is 1.15mm.

[0087] Example 2 This embodiment 2 provides a fuel filter material, the preparation method of which is as follows: 1) Preparation of the first filter layer: PBT chips with an intrinsic viscosity of 0.82 dL / g were dried, and 2% conductive carbon black was added and mixed evenly. After being melt-extruded by an extruder and metered by a metering pump, the fibers were spun and melt-blown. The fibers were then drawn and stretched into fibers under hot air pressure of 20 kPa and hot air temperature of 270℃, cooled, and wound to obtain the melt-blown outer layer material. The basis weight of this layer was 70 g / m² and the thickness was 0.30 mm.

[0088] 2) Preparation of the second filter layer: By mass fraction, 42 parts glass fiber, 51 parts PBT fiber, 4 parts carbon fiber, and 3 parts acrylic fiber are mixed evenly, and then diluted, pulped, wound, slit, and dried to obtain the intermediate layer filter material; the basis weight of this layer is 160 g / m², and the thickness is 0.75 mm.

[0089] 3) Preparation of the third filter layer: (1) NH2-MIL-125(Ti) was dispersed in a 0.15 mol / L aqueous solution of AgNO3, stirred evenly, centrifuged, washed, and spray-dried at 80°C to obtain the MOFs-supported silver ion antibacterial agent Ag. + @NH2-MIL-125(Ti); (2) PBT slices with an intrinsic viscosity of 0.75 dL / g and Ag with a mass fraction of 3% were mixed. + @NH2-MIL-125(Ti) was mixed evenly and granulated to prepare antibacterial polyester masterbatch; the antibacterial polyester masterbatch was further blended with PBT chips to reduce the Ag content in the system. + The mass fraction of @NH2-MIL-125(Ti) is 1%. After being melt-extruded by an extruder and metered by a metering pump, it is spun into melt-blown fibers. The fibers are then drawn and stretched into fibers under hot air pressure of 40 kPa and hot air temperature of 220℃. After cooling and winding, the melt-blown inner layer material is obtained. The basis weight of this layer is 60 g / m² and the thickness is 0.2 mm.

[0090] 4) Three-layer filter media composite molding: The first filter layer, the second filter layer, and the third filter layer are laid flat in sequence and fixed by point hot pressing at 210°C. After cooling and rolling, the filter material roll is obtained, which is the filter material of this embodiment. The total weight is 290g / m² and the thickness is 1.25mm.

[0091] Example 3 This embodiment 3 provides a fuel filter material, the preparation method of which is as follows: 1) Preparation of the first filter layer: PBT chips with an intrinsic viscosity of 0.80 dL / g were dried, and 1.5% conductive carbon black by mass was added and mixed evenly. After being melt-extruded by an extruder and metered by a metering pump, the fibers were spun into fibers and stretched into fibers under hot air pressure of 25 kPa and hot air temperature of 260℃. After cooling and winding, the melt-blown outer layer material was obtained. The basis weight of this layer was 55 g / m² and the thickness was 0.25 mm.

[0092] 2) Preparation of the second filter layer: By mass fraction, 41 parts glass fiber, 54 parts PBT fiber, 3.2 parts carbon fiber, and 1.8 parts PET fiber are mixed evenly, diluted, pulped, rolled, slit, and dried to obtain the intermediate layer filter material; the basis weight of this layer is 140 g / m², and the thickness is 0.55 mm.

[0093] 3) Preparation of the third filter layer: (1) MIL-101(Cr) was dispersed in a 0.2 mol / L aqueous solution of AgNO3, stirred evenly, centrifuged, washed, and spray-dried at 60°C to obtain the MOFs-loaded silver ion antibacterial agent Ag. + @MIL-101(Cr); (2) PBT slices with an intrinsic viscosity of 0.7 dL / g were mixed with Ag with a mass fraction of 3%. + @MIL-101(Cr) was mixed evenly and granulated to prepare antibacterial polyester masterbatch; the antibacterial polyester masterbatch was further blended with PBT chips to reduce Ag in the system. + @MIL-101(Cr) has a mass fraction of 0.9%. It is melt-extruded by an extruder, metered by a metering pump, and then spun into melt-blown fibers. The fibers are drawn and stretched into fibers under hot air pressure of 35 kPa and hot air temperature of 225℃, cooled, and wound to obtain the melt-blown inner layer material. The basis weight of this layer is 60 g / m² and the thickness is 0.2 mm.

[0094] 4) Three-layer filter media composite molding: The first, second, and third filter layers are laid flat in sequence and fixed by point-type hot pressing at 225°C. After cooling and rolling, a filter media roll is obtained. The filter material used in this embodiment has a total weight of 255 g / m² and a thickness of 1.0 mm.

[0095] Example 4 This embodiment 4 provides a fuel filter material, the preparation method of which is as follows: 1) Preparation of the first filter layer: PBT chips with an intrinsic viscosity of 0.85 dL / g were dried, and 0.5% graphene by mass was added and mixed evenly. After being melt-extruded by an extruder and metered by a metering pump, the fibers were spun into fibers and stretched into fibers under hot air pressure of 18 kPa and hot air temperature of 280℃. After cooling and winding, the melt-blown outer layer material was obtained. The basis weight of this layer was 65 g / m² and the thickness was 0.2 mm.

[0096] 2) Preparation of the second filter layer: By mass fraction, 41 parts glass fiber, 50 parts PBT fiber, 4 parts carbon fiber, 4 parts PTFE fiber, and 1 part basalt fiber are mixed evenly, and then diluted, pulped, rolled, slit, and dried to obtain the intermediate layer filter material; the basis weight of this layer is 170 g / m², and the thickness is 0.60 mm.

[0097] 3) Preparation of the third filter layer: (1) ZIF-8 was dispersed in a 0.2 mol / L aqueous solution of AgNO3, stirred evenly, centrifuged, washed, and spray-dried at 60°C to obtain the MOFs-loaded silver ion antibacterial agent Ag. +@ZIF-8; (2) PBT slices with an intrinsic viscosity of 0.65 dL / g and Ag with a mass fraction of 5% were mixed. + @ZIF-8 was mixed evenly and granulated to prepare antibacterial polyester masterbatch; the antibacterial polyester masterbatch was further blended with PBT chips to reduce Ag content in the system. + The ZIF-8 has a mass fraction of 1.2%. It is melt-extruded by an extruder, metered by a metering pump, and then spun into melt-blown fibers. Under the conditions of hot air pressure of 40 kPa and hot air temperature of 230℃, it is stretched into fibers, cooled, and wound to obtain the melt-blown inner layer material. The basis weight of this layer is 45 g / m², and the thickness is 0.3 mm.

[0098] 4) Three-layer filter media composite molding: The first, second, and third filter layers are laid flat in sequence and fixed by point-type hot pressing at 215°C. After cooling and rolling, a filter media roll is obtained. The filter material used in this embodiment has a total weight of 280 g / m² and a thickness of 1.1 mm.

[0099] Example 5 This embodiment 5 provides a fuel filter material, the preparation method of which is as follows: 1) Preparation of the first filter layer: PBT chips with an intrinsic viscosity of 0.85 dL / g were dried, and 3% conductive carbon black was added and mixed evenly. After being melt-extruded by an extruder and metered by a metering pump, the fibers were spun and melt-blown. The fibers were then stretched into fibers under hot air pressure of 20 kPa and hot air temperature of 280℃, cooled, and wound to obtain the melt-blown outer layer material. The basis weight of this layer was 75 g / m² and the thickness was 0.35 mm.

[0100] 2) Preparation of the second filter layer: By mass fraction, 40 parts glass fiber, 50 parts PBT fiber, 3 parts carbon fiber, 1 part PET fiber, 1 part spandex fiber, and 5 parts PTFE fiber are mixed evenly, and then diluted, pulped, wound, slit, and dried to obtain the intermediate layer filter material; the basis weight of this layer is 180 g / m², and the thickness is 0.60 mm.

[0101] 3) Preparation of the third filter layer: (1) Disperse UiO-66 in a 0.16 mol / L aqueous solution of AgNO3, stir until homogeneous, centrifuge, wash, and spray dry at 70°C to obtain the MOFs-loaded silver ion antibacterial agent Ag. + @UiO-66; (2) PBT slices with an intrinsic viscosity of 0.72 dL / g and Ag with a mass fraction of 8% were mixed. +@UiO-66 was mixed evenly and granulated to prepare antibacterial polyester masterbatch; the antibacterial polyester masterbatch was further blended with PBT chips to reduce the Ag content in the system. + @UiO-66 has a mass fraction of 1.5%. It is melt-extruded by an extruder, metered by a metering pump, and then spun into melt-blown fibers. Under the conditions of hot air pressure of 40 kPa and hot air temperature of 230℃, it is stretched into fibers, cooled, and wound to obtain the melt-blown inner layer material. The basis weight of this layer is 65 g / m², and the thickness is 0.25 mm.

[0102] 4) Three-layer filter media composite molding: The first, second, and third filter layers are laid flat in sequence and fixed by point-type hot pressing at 210°C. After cooling and rolling, a filter media roll is obtained. The filter material used in this embodiment has a total weight of 320 g / m² and a thickness of 1.2 mm.

[0103] Comparative Example 1 Comparative Example 1 provides a fuel filter material that uses a commercially available single-layer filter material of wood pulp fiber and glass fiber. It has no conductive layer, no antibacterial layer, and no gradient structure. The basis weight is 280 g / m² and the thickness is 1.15 mm.

[0104] Comparative Example 2 Comparative Example 2 provides a fuel filter material that differs from Example 1 in that the first filter layer does not contain a conductive agent. The first filter layer of this comparative example is made solely of pure PBT and does not contain carbon nanotubes.

[0105] Comparative Example 3 Comparative Example 3 provides a fuel filter media that differs from Example 1 in that the third filter layer does not contain an antibacterial agent. The third filter layer of this comparative example is made solely of pure PBT and does not contain MOFs-loaded silver ion antibacterial agents.

[0106] Performance testing 1. The fuel filter media obtained in Examples 1-5 and Comparative Examples 1-3 were tested for filtration performance, dust holding capacity, and air permeability. The specific test methods are as follows: Filtration performance testing and dust holding capacity testing: Tested according to ISO 19438.

[0107] Air permeability test: Tested according to ASTM D737, under a fixed pressure difference (usually 127 Pa, i.e. 1.25 cm H2O), measure the volume of air passing through a unit area of ​​the sample per unit time.

[0108] The test results are shown in Table 1: Table 1. Filter Media Performance Test Results

[0109] As can be seen from the data in Table 1, the fuel filter material provided by this invention, through a three-layer gradient structure design of "outer conductive melt-blown layer + middle composite fiber layer + inner antibacterial melt-blown layer", and the addition of conductive agent and MOFs-loaded silver ion antibacterial agent, achieves significant improvements in air permeability, 4μm filtration efficiency, and dust holding capacity compared to existing single-layer filter materials (Comparative Example 1), filter materials without conductive agent (Comparative Example 2), and filter materials without antibacterial agent (Comparative Example 3). It also has excellent biodiesel resistance and can be adapted to the biodiesel usage environment.

[0110] 2. The filter media prepared in Example 1 and the filter media prepared in Comparative Example 1 were respectively processed into fuel filter elements with identical specifications and dimensions. The specific preparation process is as follows: Example 1 Filter element: The three-layer composite filter material (first filter layer + second filter layer + third filter layer) described in Example 1 is used to make a cylindrical fuel filter element through folding, gluing and rolling processes.

[0111] Comparative Example 1 filter element: The single-layer filter material described in Comparative Example 1 (excluding conductive agent and antibacterial agent, with a weight equal to the sum of the three layers) is used to make a cylindrical fuel filter element through the same folding, gluing, and rolling process.

[0112] Two sets of filter elements were subjected to bench tests according to the SAE J905 fuel filter flow resistance test and the ISO 16332 oil-water separation efficiency test standards. The flow resistance at rated flow, the 4μm multi-pass filtration efficiency, and the dust holding capacity at a final pressure of 70kPa were compared. The test results are shown in Table 2. Table 2 Filter Cart Performance Test

[0113] As can be seen from the data in Table 2, under the same test conditions, the 4μm multi-pass filtration efficiency of the filter element of Example 1 of the present invention is higher, the flow resistance is lower, and the dust holding capacity is larger. Its overall filtration performance is significantly better than that of the filter element of Comparative Example 1 made of traditional commercially available filter materials, and it is more suitable for the high precision and long service life requirements of biodiesel fuel systems.

[0114] In the description of this specification, the references to terms such as "one embodiment / mode," "some embodiments / modes," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment / mode or example is included in at least one embodiment / mode or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment / mode or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments / modes or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments / modes or examples described in this specification, as well as the features of different embodiments / modes or examples.

[0115] It should be noted that in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. In this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise expressly specified.

[0116] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features of the invention herein.

Claims

1. A fuel filter media, characterized in that, The fuel filter media includes a first filter layer, a second filter layer and a third filter layer stacked in sequence, wherein the raw material components of the first filter layer include polybutylene terephthalate and a conductive agent. The raw material components of the second filter layer include glass fiber, polybutylene terephthalate fiber, conductive fiber, and auxiliary fiber; The raw material components of the third filter layer include polybutylene terephthalate and antibacterial agents.

2. The fuel filter media as described in claim 1, characterized in that, Based on the total mass of the first filter layer, the conductive agent accounts for 0.5%-3% of the total mass; and / or, The conductive agent is selected from at least one of conductive carbon black, carbon nanotubes, and graphene materials; and / or, In the first filter layer, the intrinsic viscosity of the polybutylene terephthalate is 0.75 dL / g-0.85 dL / g.

3. The fuel filter media as described in claim 1, characterized in that, In the second filter layer, the glass fiber accounts for 40%-45% of the mass, the polybutylene terephthalate fiber accounts for 50%-55% of the mass, the conductive fiber accounts for 3%-5% of the mass, and the auxiliary fiber accounts for 1%-7% of the mass; and / or, The conductive fiber includes carbon fiber; and / or, The auxiliary fiber is selected from at least one of acrylic fiber, PET fiber, basalt fiber, PTFE fiber and spandex fiber.

4. The fuel filter media as described in claim 1, characterized in that, Based on the total mass of the third filter layer, the antibacterial agent accounts for 0.8%-1.5% of the total mass; and / or, The antibacterial agent includes a silver ion-supported antibacterial agent on a metal-organic framework material; and / or... The metal-organic framework material is selected from one of UiO-66-NH2, UiO-66, NH2-MIL-125(Ti), MIL-101(Cr), and ZIF-8; and / or, In the third filter layer, the intrinsic viscosity of the polybutylene terephthalate is 0.65 dL / g-0.75 dL / g.

5. The fuel filter media as described in claim 1, characterized in that, The weight ratio of the first filter layer, the second filter layer and the third filter layer is (50-75):(130-180):(45-65).

6. The fuel filter media as described in claim 1, characterized in that, The thickness of the fuel filter media is 1.0-1.35 mm.

7. The fuel filter media as described in claim 1, characterized in that, The fuel filter media has a gradient filtration structure, wherein the first filter layer is used to filter particulate matter with a particle size greater than 10 μm, the second filter layer is used to filter particulate matter with a particle size of 4-10 μm, and the third filter layer is used to filter particulate matter with a particle size less than 4 μm.

8. A method for preparing fuel filter media as described in any one of claims 1-7, characterized in that, Includes the following steps: The first filter layer is obtained by blending a conductive agent with polybutylene terephthalate and then processing it by melt-blowing. The second filter layer is prepared by mixing glass fiber, polybutylene terephthalate fiber, conductive fiber and auxiliary fiber, followed by pulping, molding and drying. The third filter layer is prepared by blending antibacterial agent with polybutylene terephthalate and then using a melt-blowing process. The first filter layer, the second filter layer, and the third filter layer are hot-pressed to form the fuel filter material.

9. The method for preparing fuel filter media as described in claim 8, characterized in that, In the step of preparing the first filter layer, the hot air pressure of the meltblown process is 15-25 kPa, and the hot air temperature is 260-290℃; and / or, In the step of preparing the third filter layer, the hot air pressure of the meltblown process is 25-40 kPa, and the hot air temperature is 220-230℃; and / or, The temperature for point-type hot pressing is 205℃-225℃.

10. A fuel filter, characterized in that, Includes fuel filter media as described in any one of claims 1-7.

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