Antibacterial multi-gradient air filter, filter material and preparation method thereof

Abstract

The present invention discloses an antibacterial multi-gradient air filter, a filter material and a preparation method thereof. The present invention adopts a three-gradient fiber layer structure with a certain thickness, and after multiple cold-setting and heat-setting processes, an antibacterial multi-gradient filter material is prepared as the filter body of the antibacterial multi-gradient air filter. The filter made of this material as the main body has the advantages of low resistance, high filtration efficiency, high dust holding capacity, and can adapt to the high humidity and high salt environment of the ocean. At the same time, it also has the functions of filtering droplets, salt, dust, and virus aerosol particles. In addition, the antibacterial multi-gradient air filter provided by the present invention can be designed in plate, box and bag types according to different filtering requirements, and can be applied to different application scenarios such as ship cabin delivery, return air and ventilation between cabins, and has excellent applicability and practical effect.

Description

Technical Field

[0001] The invention belongs to the field of ship air purification, and in particular relates to an antibacterial multi-gradient air filter, a filter material and a preparation method thereof. Background Art

[0002] The ship cabin ventilation system is a system for air exchange between the various cabins of the ship. The existing ship cabin ventilation systems generally do not have air purification and disinfection functions, making it difficult to ensure the health of cabin personnel. Existing ship cabin supply and return air usually use coarse-effect filter materials made of metal or non-metallic wire mesh with a simple woven structure. This coarse-effect filter has poor filtering effect and mainly serves to prevent the inhalation of foreign matter. After being used for a long time on ships and in environments with high humidity, it will become a breeding ground for viruses and bacteria. Some ships with higher requirements for environmental comfort install coarse and medium-efficiency filter materials at the cabin air supply outlets, but this type of material is usually not designed for the marine environment, cannot adapt to high humidity, and does not consider the needs of virus aerosol prevention and control.

[0003] Since the aerosols carrying viruses are small in size, the existing coarse or medium efficiency filter materials have poor filtering effects on them; if the filtering efficiency of the existing filters is upgraded and replaced with high efficiency filters made of high efficiency filter paper, it will bring too much resistance, high operating energy consumption, high fan energy consumption requirements, and even affect the ventilation volume. At the same time, since the air in the marine environment is characterized by high humidity and high salt, the filter materials used for filtering and purification in the cabin must be resistant to moisture and salt corrosion.

[0004] Chinese patent application CN94113377.X discloses "a bactericidal air purification material and its preparation", and discloses an air purification material with three functions of filtration, adsorption and sterilization and its preparation method. The purification material is composed of a surface fiber bactericide, a 0-0.3 mm polypropylene ultrafine fiber filter cloth, a polypropylene fiber mesh and an activated carbon fiber mesh. The preparation method includes: carbon finishing the fiber mesh, needle punching composite, dust removal and smoke filtering finishing, sterilization finishing, drying and other steps. The purification material provided by this method has the characteristics of small air resistance, high sterilization, adsorption and filtration efficiency, and arbitrary shaping. However, the material cannot adapt to the marine environment with high air humidity. Since the virus has the characteristics of aerosol transmission and the aerosol carrying the virus is small in size, the filter material cannot effectively filter the virus.

[0005] Chinese patent application CN212596385U discloses a ship air disinfection and purification device, which is composed of several structures with a certain accommodation space stacked together to accommodate a friction nano-power generation unit; the friction nano-power generation unit includes a shell and a nano-sphere in the shell, with a slight gap between the shell and the shell, and uninterrupted contact with the shell; the inner surface of the shell is sprayed with an aluminum or copper electrode as the positive electrode of the friction nano-power generation unit; the nano-sphere is the negative electrode of the friction nano-power generation unit, and the friction contact with the positive electrode causes the micro-nano structure on its surface to generate a displacement current, thereby establishing an electrostatic field, and converting the kinetic energy and pressure energy of the airflow into a high-voltage electrostatic field inside the purification device for air purification. This method purifies the air by a high-voltage electric field, which can achieve the effect of purification and disinfection to a certain extent, but the high-voltage electric field is prone to sparks under high humidity conditions, further causing safety hazards such as fire.

[0006] Considering the needs of cabin supply and return air and ventilation between cabins, it is very necessary to develop a filter material with low resistance, high filtration efficiency, high dust holding capacity, which can adapt to the high humidity and high salt environment of the ocean, has the function of filtering out droplets, salt, dust, viral aerosol particles, and can inhibit bacteria and inactivate viruses, and can be used for cabin supply and return air and ventilation between cabins. Summary of the invention

[0007] To overcome the above problems, the present invention provides a cabin ventilation filter which has antibacterial and microbial inactivation effects, is adaptable to high humidity and high salt environments, and can be repeatedly washed and used multiple times, as well as a filter material used with the filter and a preparation method thereof.

[0008] The object of the present invention is achieved through the following scheme: an antibacterial multi-gradient air filter comprises a filter material and a frame.

[0009] The filter material has a multi-gradient fiber layer structure, including an ultra-fine fiber layer, a fine fiber layer and a coarse fiber layer arranged in a gradually dense manner along the air flow direction.

[0010] The frame is arranged around the filter material and fixed to the filter material by means of a sealant.

[0011] Air filters include three types: flat plate, box and bag filters.

[0012] The flat plate filter includes a flat antibacterial multi-gradient filter material and a flat plate frame.

[0013] The box filter consists of 3 to 6 antibacterial multi-gradient filter materials and frames folded into a "V" shape.

[0014] The bag filter consists of 3 to 6 antibacterial multi-gradient filter materials and frames folded into a "bag shape".

[0015] Preferably, in the flat filter, a double-layer metal mesh is used to clamp the antibacterial multi-gradient filter material from top to bottom and lay it flat, and the material is sealed with the frame by a sealant.

[0016] Preferably, in the flat-plate, box-type and bag-type filters, the thickness of a single antibacterial multi-gradient filter material is 8 mm to 15 mm.

[0017] The present invention also provides an antibacterial multi-gradient filter material for making the antibacterial multi-gradient air filter.

[0018] The antibacterial multi-gradient filter material has a multi-gradient fiber layer structure, which includes:

[0019] A microfiber layer formed by mixing the main microfiber with the secondary fiber;

[0020] A fine fiber layer formed by mixing main fine fibers with secondary fibers;

[0021] The coarse fiber layer is formed by mixing the main coarse fibers with the secondary fibers.

[0022] The multi-gradient fiber layer structure is arranged in a gradually dense manner along the airflow direction, and the specific order is: coarse fiber layer-fine fiber layer-ultrafine fiber layer.

[0023] The fiber diameter of each fiber layer in the multi-gradient fiber layer structure gradually decreases along the airflow direction, and a super-hydrophobic film is formed on the surface of each fiber layer.

[0024] The present invention also provides a method for preparing an antibacterial multi-gradient filter material, which is used to prepare the antibacterial multi-gradient filter material in the above filter, and specifically comprises the following steps:

[0025] S1 fiber blending: the opened main microfibers are mixed with the secondary fibers to form a microfiber layer, and a carding machine is used to lay the bottom layer;

[0026] The opened main fine fibers are mixed with the secondary fibers to form a fine fiber layer, and a carding machine is used for middle-layer web laying;

[0027] The loosened main coarse fibers are mixed with the secondary fibers to form a coarse fiber layer, and a carding machine is used to lay the upper layer to obtain a multi-gradient fiber layer structure.

[0028] S2 hot melt bonding: The multi-gradient fiber layer structure obtained in S1 was hot-melted at 150° C.-200° C. for 4 min-12 min using a chain-driven box-type hot air oven.

[0029] S3 cold rolling and shaping: the hot-melted multi-gradient fiber layer structure is cold rolled and shaped at 10°C-20°C by using a pair of rollers, with a driving speed of 5m / min-10m / min, to obtain a raw material of the multi-gradient fiber layer structure.

[0030] S4 hydrophobic flame retardant treatment: prepare 4%-12% polytetrafluoroethylene hydrophobic flame retardant emulsion, and make the multi-gradient fiber layer structure raw material obtained in S3 be immersed in the polytetrafluoroethylene hydrophobic flame retardant emulsion to form a super hydrophobic film on the surface of the multi-gradient fiber layer structure raw material.

[0031] S5 hot rolling shaping: the multi-gradient fiber layer structure raw material passed through the polytetrafluoroethylene hydrophobic flame retardant emulsion in S4 is hot-pressed by using oil-heated hot rollers at 140°C-220°C, with a driving speed of 5m / min-10m / min to obtain a multi-gradient fiber layer structure filter material.

[0032] S6 air cooling and shaping: the multi-gradient fiber layer structure filter material obtained in S5 is passed through a guide roller provided with ventilation holes to cool and shape it, and then trimmed and cut to obtain a multi-gradient fiber layer structure material.

[0033] S7 antibacterial treatment: Add nano silver powder and surface additives into water, ultrasonicate and stir evenly to obtain a nano silver solution, immerse the trimmed and cut multi-gradient fiber layer structure material into the nano silver solution, adjust the pH to 7.5-8.5, heat to 60℃-80℃ and keep warm for 40min-60min, take out the multi-gradient fiber layer structure material, roll and dry it to obtain an antibacterial multi-gradient filter material.

[0034] Preferably, in step S1, in the ultrafine fiber layer, the fine fiber layer and the coarse fiber layer, the main ultrafine fibers, the main fine fibers and the main coarse fibers are PET fibers or PP fibers, and the secondary fibers are ES fibers.

[0035] Preferably, in step S1, in the ultrafine fiber layer, the fine fiber layer and the coarse fiber layer, the proportion of the main ultrafine fibers, the main fine fibers and the main coarse fibers is 70%-80%.

[0036] Preferably, in step S1, the main coarse fibers in the coarse fiber layer are long fibers or short fibers prepared by conventional spinning, and the fiber diameter is 2 μm-10 μm.

[0037] Preferably, in step S1, the main fine fibers in the fine fiber layer are short fibers prepared by electrospinning, and the fiber diameter is 400nm-800nm.

[0038] Preferably, in step S1, the main ultrafine fibers in the ultrafine fiber layer are long fibers or short fibers prepared by microfluidic air-jet spinning technology or electrostatic spinning technology, and the fiber diameter is 60nm-200nm.

[0039] Preferably, in step S1, the ratio of the ultrafine fiber layer, the fine fiber layer and the coarse fiber layer in the multi-gradient fiber layer structure is: ultrafine fiber layer: fine fiber layer: coarse fiber layer = 30%-40%: 30%-40%: 20%-40%.

[0040] Preferably, in step S7, the nanosilver solution is obtained by adding the nanosilver dispersion, the dispersant and the surface additive into water, and then subjecting the mixture to ultrasonication and stirring.

[0041] Compared with the prior art, the present invention has the following advantages:

[0042] 1. The filter provided by the present invention adopts an antibacterial multi-gradient filter material with a certain thickness. The density of the three-layer fiber material is getting denser and the wire diameter is getting finer along the direction of the airflow. This design makes the filter material present an obvious three-dimensional structure in the direction of the airflow. Particles of different sizes are captured in fiber layers with different fiber diameters and densities. Fibers and fiber layers of different diameters are used to their full potential, which improves the dust collection efficiency of the filter material. The ultrafine fiber layer with a fiber diameter of 60nm-200nm has a good filtering effect on the new coronavirus with a size of 60nm-140nm, and the ultrafine fiber prepared by microfluidic air jet spinning technology or electrostatic spinning technology can still achieve a sub-high efficiency filtration level of filtration efficiency under low resistance.

[0043] 2. The filter material used in the filter of the present invention has been treated with super-hydrophobicity to form a super-hydrophobic film on the surface of each layer of fiber of the antibacterial multi-gradient filter material. When there is moisture in the filtered air, water mist or water droplets are captured by the fibers, and small water droplets gather and grow on the super-hydrophobic fiber surface to form larger droplets that drip. The salt particles captured on the fibers will dissolve in the water and be removed, and the solid particles insoluble in water will also be removed as the liquid drips, which effectively delays the increase in resistance, increases the actual dust holding capacity of the filter material, and extends its service life.

[0044] 3. The filter material used in the filter of the present invention has been treated with silver-loaded antibacterial agents. The silver ion sterilization effect can effectively inhibit and kill microorganisms and viruses captured on the fiber surface, and inhibit the spread of viruses between cabins through aerosols. The material is suitable for an environmental humidity of more than 70% RH, and has obvious antibacterial and microbial inactivation effects.

[0045] 4. The filter material used in the filter of the present invention has been processed by multiple cold-setting and hot-setting methods, which increases the stiffness and elasticity of the filter material, changes its one-time use status, and can be repeatedly washed and used multiple times, effectively extending the service life of the filter material, meeting the needs of ships for ocean-going missions and special driving conditions without replacement and repeated use. Repeated washing and reuse ≥ 10 times.

[0046] 5. The filter of the present invention can be manufactured into a flat plate, bag or box filter suitable for cabin air supply and return ports according to the specific installation space and filtration flow rate of the ship for air filtration. Among them, the flat plate filter is suitable for installation in the occasion where the diameter and depth of the space are small and the air flow rate is low, and the bag filter is suitable for installation in the occasion where the diameter and depth of the space are large and the air flow rate is large. When the wind speed is 1m / s-2m / s, the bag filter can reduce the filter material resistance from within 100Pa to within 30Pa, and the efficiency reaches the sub-high efficiency filtration level. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is a schematic diagram of the structure of the antibacterial multi-gradient filter material in the present invention;

[0048] Figure 2 It is a schematic diagram of the structure of the flat plate filter in the present invention;

[0049] Figure 3 It is a schematic diagram of the bag filter structure of the present invention;

[0050] Figure 4 It is a schematic diagram of the box filter structure of the present invention;

[0051] Figure 5 The figure is a flow chart for preparing the antibacterial multi-gradient filter material of the present invention. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] The technical solution of the present invention provides an antibacterial multi-gradient filter, comprising a filter material and a frame.

[0054] like Figures 1 to 4 As shown, the filter material used in the antibacterial multi-gradient filter is a multi-gradient fiber layer structure, including an ultra-fine fiber layer, a fine fiber layer and a coarse fiber layer arranged in a gradually dense manner along the air flow direction.

[0055] The frame is arranged around the filter material and fixed to the filter material by means of a sealant.

[0056] Air filters include three types: flat plate, box and bag filters.

[0057] The flat plate filter includes a flat antibacterial multi-gradient filter material and a flat plate frame.

[0058] The box filter consists of 3 to 6 antibacterial multi-gradient filter materials and frames folded into a "V" shape.

[0059] The bag filter consists of 3 to 6 antibacterial multi-gradient filter materials and frames folded into a "bag shape".

[0060] In some embodiments of the present invention, a double-layer metal mesh is used to clamp an antibacterial multi-gradient filter material with a thickness of 8 mm from top to bottom and spread it flat, and then sealed with a frame by sealant to obtain a flat filter, which is applied to the cabin supply and return air vents.

[0061] In some embodiments of the present invention, three antibacterial multi-gradient filter materials with a thickness of 15 mm are folded into a "bag shape" and arranged in a frame, and sealed with the frame by sealant to obtain a "bag-type" antibacterial multi-gradient filter, which is used for cabin supply and return air outlets.

[0062] In some embodiments of the present invention, six antibacterial multi-gradient filter materials with a thickness of 10 mm are folded into a "V" shape and arranged in a frame. The V-shaped support structure can further strengthen the firmness of the antibacterial multi-gradient filter material in the frame. The antibacterial multi-gradient filter material is sealed with the frame by sealant to obtain a "box-type" antibacterial multi-gradient filter, which is applied to the cabin supply and return air outlets.

[0063] The technical solution of the present invention also provides an antibacterial multi-gradient filter material, which is used to make the above-mentioned filter and has a multi-gradient fiber layer structure, including:

[0064] A microfiber layer formed by mixing the main microfiber with the secondary fiber;

[0065] A fine fiber layer formed by mixing main fine fibers with secondary fibers;

[0066] The coarse fiber layer is formed by mixing the main coarse fibers with the secondary fibers.

[0067] The multi-gradient fiber layer structure is arranged in a gradually dense manner along the airflow direction, and the specific order is: coarse fiber layer-fine fiber layer-ultrafine fiber layer. The fiber diameters used in each fiber layer of the multi-gradient fiber layer structure gradually decrease along the airflow direction.

[0068] The surface of each fiber layer of the multi-gradient fiber layer structure is provided with a super-hydrophobic film.

[0069] The technical solution of the present invention also provides a method for preparing an antibacterial multi-gradient filter material, which is used to prepare the antibacterial multi-gradient filter material. The specific preparation process is as follows: Figure 5 shown.

[0070] In some embodiments of the present invention, the method for preparing the antibacterial multi-gradient material comprises the following steps:

[0071] S1 fiber blending: PET is selected as the main fiber and ES is selected as the secondary fiber.

[0072] The opened PET microfibers are mixed with ES fibers to form a microfiber layer, and a carding machine is used to lay the bottom layer;

[0073] The opened PET fine fibers are mixed with ES fibers to form a fine fiber layer, and a carding machine is used for middle-layer web laying;

[0074] The opened PET coarse fibers are mixed with ES fibers to form a coarse fiber layer, and a carding machine is used to lay the upper layer to obtain a multi-gradient fiber layer structure.

[0075] The multi-gradient fiber layer structure is arranged in a gradually dense manner along the airflow direction, and the specific order is: coarse fiber layer-fine fiber layer-ultrafine fiber layer. The fiber diameters used in each fiber layer of the multi-gradient fiber layer structure gradually decrease along the airflow direction.

[0076] The PET fibers in the coarse fiber layer are long fibers prepared by conventional spinning, with a fiber diameter of 2 μm;

[0077] The PET fibers in the fine fiber layer are short fibers prepared by electrospinning, with a fiber diameter of 400 nm;

[0078] The PET fibers in the ultrafine fiber layer are long fibers prepared by microfluidic air-jet spinning technology, and the fiber diameter is 60 nm.

[0079] In each fiber layer, PET fiber accounts for 70%.

[0080] The proportion of each fiber layer in the multi-gradient fiber layer structure is: ultra-fine fiber layer: fine fiber layer: coarse fiber layer = 30%: 30%: 40%.

[0081] S2 hot melt bonding: The multi-gradient fiber layer structure obtained in S1 was hot-melt bonded at 150°C for 4 min using a chain-driven box-type hot air oven.

[0082] S3 cold rolling and shaping: the hot-melted multi-gradient fiber layer structure is cold rolled and shaped at 10°C using a pair of rollers at a driving speed of 5m / min to obtain a raw material of the multi-gradient fiber layer structure.

[0083] S4 hydrophobic flame retardant treatment: prepare 4% polytetrafluoroethylene hydrophobic flame retardant emulsion, and make the multi-gradient fiber layer structure raw material obtained in S3 be immersed in the polytetrafluoroethylene hydrophobic flame retardant emulsion to form a super hydrophobic film on the surface of the multi-gradient fiber layer structure raw material.

[0084] S5 hot rolling shaping: the multi-gradient fiber layer structure raw material passed through the polytetrafluoroethylene hydrophobic flame retardant emulsion in S4 is hot-pressed with an oil-heated hot roller at 140°C, with a driving speed of 5m / min to obtain a multi-gradient fiber layer structure filter material.

[0085] S6 air cooling and shaping: the multi-gradient fiber layer structure filter material obtained in S5 is passed through a guide roller provided with ventilation holes to cool and shape it, and then trimmed and cut to obtain a multi-gradient fiber layer structure material.

[0086] S7 antibacterial treatment: Add nano silver powder and surface additives into water, ultrasonicate and stir evenly to obtain a nano silver solution, immerse the trimmed and cut multi-gradient fiber layer structure material into the nano silver solution, adjust the pH to 7.5, heat to 60°C and keep warm for 40 minutes, take out the multi-gradient fiber layer structure material, roll and dry it to obtain an antibacterial multi-gradient filter material with a thickness of 8 mm.

[0087] In some embodiments of the present invention, the method for preparing the antibacterial multi-gradient material comprises the following steps:

[0088] S1 fiber blending: PET is selected as the main fiber and ES is selected as the secondary fiber.

[0089] The opened PET microfibers are mixed with ES fibers to form a microfiber layer, and a carding machine is used to lay the bottom layer;

[0090] The opened PET fine fibers are mixed with ES fibers to form a fine fiber layer, and a carding machine is used for middle-layer web laying;

[0091] The opened PET coarse fibers are mixed with ES fibers to form a coarse fiber layer, and a carding machine is used to lay the upper layer to obtain a multi-gradient fiber layer structure.

[0092] The multi-gradient fiber layer structure is arranged in a gradually dense manner along the airflow direction, and the specific order is: coarse fiber layer-fine fiber layer-ultrafine fiber layer. The fiber diameters used in each fiber layer of the multi-gradient fiber layer structure gradually decrease along the airflow direction.

[0093] The PET fibers in the coarse fiber layer are short fibers prepared by conventional spinning, with a fiber diameter of 10 μm;

[0094] The PET fibers in the fine fiber layer are short fibers prepared by electrospinning, with a fiber diameter of 800 nm;

[0095] The PET fibers in the ultrafine fiber layer are short fibers prepared by electrospinning technology, and the fiber diameter is 200 nm.

[0096] In each fiber layer, PET fiber accounts for 80%.

[0097] The proportion of each fiber layer in the overall fiber layer structure is: ultrafine fiber layer: fine fiber layer: coarse fiber layer = 40%: 40%: 20%.

[0098] S2 hot melt bonding: The multi-gradient fiber layer structure obtained in S1 was hot-melted at 200°C for 12 min using a chain-driven box-type hot air oven.

[0099] S3 cold rolling and shaping: the hot-melted multi-gradient fiber layer structure is cold rolled and shaped at 20°C using a pair of rollers at a driving speed of 10 m / min to obtain a raw material of the multi-gradient fiber layer structure.

[0100] S4 hydrophobic flame retardant treatment: 12% polytetrafluoroethylene hydrophobic flame retardant emulsion is prepared, and the multi-gradient fiber layer structure raw material obtained in S3 is impregnated through the polytetrafluoroethylene hydrophobic flame retardant emulsion to form a super hydrophobic film on the surface of the multi-gradient fiber layer structure raw material.

[0101] S5 hot rolling shaping: the multi-gradient fiber layer structure raw material passed through the polytetrafluoroethylene hydrophobic flame retardant emulsion in S4 is hot-pressed with an oil-heated hot roller at 220°C, with a driving speed of 10m / min to obtain a multi-gradient fiber layer structure filter material.

[0102] S6 air cooling and shaping: the multi-gradient fiber layer structure filter material obtained in S5 is passed through a guide roller provided with ventilation holes to cool and shape it, and then trimmed and cut to obtain a multi-gradient fiber layer structure material.

[0103] S7 antibacterial treatment: Add nano-silver powder and surface additives into water, ultrasonicate and stir evenly to obtain a nano-silver solution, immerse the trimmed and cut multi-gradient fiber layer structure material into the nano-silver solution, adjust the pH to 8.5, heat to 80°C and keep warm for 60 minutes, take out the multi-gradient fiber layer structure material, roll and dry it to obtain an antibacterial multi-gradient filter material with a thickness of 15 mm.

[0104] In some embodiments of the present invention, the method for preparing the antibacterial multi-gradient material comprises the following steps:

[0105] S1 fiber blending: PP is selected as the main fiber and ES is selected as the secondary fiber.

[0106] The opened PP microfiber is mixed with the ES fiber to form a microfiber layer, and a carding machine is used to lay the bottom layer;

[0107] The opened PP fine fibers are mixed with ES fibers to form a fine fiber layer, and a carding machine is used for middle-layer web laying;

[0108] The opened PP coarse fibers are mixed with ES fibers to form a coarse fiber layer, and a carding machine is used to lay the upper layer to obtain a multi-gradient fiber layer structure.

[0109] The multi-gradient fiber layer structure is arranged in a gradually dense manner along the airflow direction, and the specific order is: coarse fiber layer-fine fiber layer-ultrafine fiber layer. The fiber diameters used in each fiber layer of the multi-gradient fiber layer structure gradually decrease along the airflow direction.

[0110] The PP fibers in the coarse fiber layer are long fibers prepared by conventional spinning, with a fiber diameter of 5 μm;

[0111] The PET fibers in the fine fiber layer are short fibers prepared by electrospinning, with a fiber diameter of 600 nm;

[0112] The PET fibers in the ultrafine fiber layer are long fibers prepared by microfluidic air-jet spinning technology, and the fiber diameter is 100 nm.

[0113] In each fiber layer, PP fiber accounts for 75%.

[0114] The proportion of each fiber layer in the overall fiber layer structure is: ultrafine fiber layer: fine fiber layer: coarse fiber layer = 35%: 35%: 30%.

[0115] S2 hot melt bonding: The multi-gradient fiber layer structure obtained in S1 was hot-melted at 180°C for 8 minutes using a chain-driven box-type hot air oven.

[0116] S3 cold rolling and shaping: the hot-melted multi-gradient fiber layer structure is cold rolled and shaped at 15°C using a pair of rollers at a driving speed of 8m / min to obtain a raw material of the multi-gradient fiber layer structure.

[0117] S4 hydrophobic flame retardant treatment: 8% polytetrafluoroethylene hydrophobic flame retardant emulsion is prepared, and the multi-gradient fiber layer structure raw material obtained in S3 is immersed in the polytetrafluoroethylene hydrophobic flame retardant emulsion to form a super hydrophobic film on the surface of the multi-gradient fiber layer structure raw material.

[0118] S5 hot rolling shaping: the multi-gradient fiber layer structure raw material passed through the polytetrafluoroethylene hydrophobic flame retardant emulsion in S4 is hot-pressed at 180°C using an oil-heated hot roller, with a driving speed of 8m / min to obtain a multi-gradient fiber layer structure filter material.

[0119] S6 air cooling and shaping: the multi-gradient fiber layer structure filter material obtained in S5 is passed through a guide roller provided with ventilation holes to cool and shape it, and then trimmed and cut to obtain a multi-gradient fiber layer structure material.

[0120] S7 antibacterial treatment: Add nanosilver dispersion, dispersant and surface additive into water, obtain nanosilver solution through ultrasonic and stirring, immerse the trimmed multi-gradient fiber layer structure material into the nanosilver solution, adjust the pH to 8, heat to 70°C and keep warm for 50 minutes, take out the multi-gradient fiber layer structure material, roll and dry it to obtain an antibacterial multi-gradient filter material with a thickness of 10 mm.

[0121] The above embodiments are only used to illustrate the present invention, rather than to limit the present invention. Those skilled in the art may make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also belong to the scope of the present invention and should be defined by the claims.

Claims

1. A method for preparing an antibacterial multi-gradient filter material, characterized in that: The method comprises the following steps: S1 fiber blending: the opened main microfibers are mixed with the secondary fibers to form a microfiber layer, and a carding machine is used to lay the bottom layer; The opened main fine fibers are mixed with the secondary fibers to form a fine fiber layer, and a carding machine is used for middle-layer web laying; The opened main coarse fibers are mixed with the secondary fibers to form a coarse fiber layer, and a carding machine is used to lay the upper layer to obtain a multi-gradient fiber layer structure; S2 hot melt bonding: The multi-gradient fiber layer structure obtained in S1 was hot-melted at 150°C-200°C for 4min-12min using a chain-driven box-type hot air oven; S3 cold rolling and shaping: cold rolling and shaping the hot-melted multi-gradient fiber layer structure at 10°C-20°C by using a pair of rollers, with a driving speed of 5m / min-10m / min, to obtain a raw material of the multi-gradient fiber layer structure; S4 hydrophobic flame retardant treatment: preparing 4%-12% polytetrafluoroethylene hydrophobic flame retardant emulsion, and making the multi-gradient fiber layer structure raw material obtained in S3 be immersed in the polytetrafluoroethylene hydrophobic flame retardant emulsion, so that a super hydrophobic film is formed on the surface of the multi-gradient fiber layer structure raw material; S5 hot rolling shaping: hot pressing the multi-gradient fiber layer structure raw material that has passed through the polytetrafluoroethylene hydrophobic flame retardant emulsion in S4 with an oil-heated hot roller at 140°C-220°C, with a driving speed of 5m / min-10m / min to obtain a multi-gradient fiber layer structure filter material; S6 air cooling and shaping: passing the multi-gradient fiber layer structure filter material obtained in S5 through a guide roller provided with ventilation holes to cool and shape it, and trimming and cutting it to obtain a multi-gradient fiber layer structure material; S7 antibacterial treatment: adding nano silver powder and surface additives into water, ultrasonicating and stirring to obtain a nano silver solution, immersing the trimmed multi-gradient fiber layer structure material into the nano silver solution, adjusting the pH to 7.5-8.5, heating to 60°C-80°C and keeping warm for 40min-60min, taking out the multi-gradient fiber layer structure material, rolling and drying to obtain an antibacterial multi-gradient filter material.

2. The method for preparing an antibacterial multi-gradient filter material according to claim 1, characterized in that: In the step S1, in the ultrafine fiber layer, the fine fiber layer and the coarse fiber layer, the main ultrafine fibers, the main fine fibers and the main coarse fibers are PET fibers or PP fibers, and the secondary fibers are ES fibers.

3. The method for preparing an antibacterial multi-gradient filter material according to claim 1, characterized in that: In the step S1, in the ultrafine fiber layer, the fine fiber layer and the coarse fiber layer, the main ultrafine fibers, the main fine fibers and the main coarse fibers account for 70%-80%.

4. The method for preparing an antibacterial multi-gradient filter material according to claim 1, characterized in that: In the step S1, the main coarse fibers in the coarse fiber layer are long fibers or short fibers prepared by conventional spinning, and the fiber diameter is 2 μm-10 μm; The main fine fibers in the fine fiber layer are short fibers prepared by electrospinning, and the fiber diameter is 400nm-800nm; The main ultrafine fibers in the ultrafine fiber layer are long fibers or short fibers prepared by microfluidic air-jet spinning technology or electrostatic spinning technology, and the fiber diameter is 60nm-200nm.

5. The method for preparing an antibacterial multi-gradient filter material according to claim 1, characterized in that: In the step S1, the proportion of the ultrafine fiber layer, the fine fiber layer and the coarse fiber layer in the multi-gradient fiber layer structure is: ultrafine fiber layer: fine fiber layer: coarse fiber layer = 30%-40%: 30%-40%: 20%-40%.

6. The method for preparing an antibacterial multi-gradient filter material according to claim 1, characterized in that: In the step S7, the nanosilver solution is obtained by adding nanosilver dispersion, dispersant and surface additive into water, and then ultrasonicating and stirring.

7. An antibacterial multi-gradient filter material, characterized in that: The material is prepared by the method for preparing the antibacterial multi-gradient filter material according to any one of claims 1 to 6; The antibacterial multi-gradient filter material has a multi-gradient fiber layer structure, and the multi-gradient fiber layer structure includes: The ultrafine fiber layer is formed by mixing main ultrafine fibers with secondary fibers; The fine fiber layer is formed by mixing main fine fibers and minor fibers; The coarse fiber layer is formed by mixing main coarse fibers and secondary fibers; The multi-gradient fiber layer structure is arranged in a gradually dense manner along the airflow direction, and the specific order is: coarse fiber layer-fine fiber layer-ultrafine fiber layer; The fiber diameters used in each fiber layer of the multi-gradient fiber layer structure gradually decrease along the airflow direction; The surface of each fiber layer of the multi-gradient fiber layer structure is provided with a super-hydrophobic film.

8. An antibacterial multi-gradient air filter, comprising a filter material and a frame, characterized in that: The filter material adopts the antibacterial multi-gradient filter material according to claim 7, and the filter material has a multi-gradient fiber layer structure, and the multi-gradient fiber layer structure includes an ultra-fine fiber layer, a fine fiber layer and a coarse fiber layer arranged in a gradually dense manner along the airflow direction; The frame is arranged around the filter material and fixed to the filter material by a sealant; The air filters include three types: flat plate type, box type and bag type; The flat plate filter comprises the antibacterial multi-gradient filter material and a flat plate frame which are laid flat; The box filter includes 3 to 6 antibacterial multi-gradient filter materials and a frame folded into a "V" shape; The bag filter comprises 3 to 6 pieces of the antibacterial multi-gradient filter material folded into a "bag shape" and a frame.

9. The antibacterial multi-gradient air filter according to claim 8, characterized in that: In the flat filter, a double-layer metal mesh is used to clamp the antibacterial multi-gradient filter material from top to bottom and lay it flat, and is sealed with the frame by a sealant.

10. The antibacterial multi-gradient air filter according to claim 8, characterized in that: In the flat-plate, box-type and bag-type filters, the thickness of a single antibacterial multi-gradient filter material is 8 mm to 15 mm.

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