A filter cartridge capable of inhibiting bacteria for an automobile air conditioner and a method of manufacturing the same

Abstract

This invention provides an automotive air conditioning filter element capable of inhibiting bacteria and its preparation method. The preparation method includes the following steps: (1) preparing modified nano zinc oxide; (2) adding modified nano zinc oxide to N,N-dimethylacetamide, ultrasonically dispersing for 0.5-1.5 hours, adding modified polypropylene resin, KH550, and modified filler for mixing, stirring at room temperature, and melt spinning through a meltblown spinning machine to obtain a composite meltblown fabric; (3) combining one layer of composite meltblown fabric and two layers of 3mm thick activated carbon fiber felt with hot melt adhesive, bonding the activated carbon fiber felts together with hot melt adhesive, and then bonding one layer of composite meltblown fabric to the topmost activated carbon fiber felt with hot melt adhesive, and finally performing hot pressing, cold air shaping, folding, cutting, and sealing to obtain the automotive air conditioning filter element capable of inhibiting bacteria. The filter element of this invention has excellent antibacterial effect.

Description

Technical Field

[0001] This invention belongs to the technical field of automotive air conditioning filter elements, specifically relating to an automotive air conditioning filter element capable of inhibiting bacteria and its preparation method. Background Technology

[0002] Car air conditioning filters that inhibit bacteria are often referred to as antibacterial or antimicrobial filters. These filters effectively reduce the number of bacteria and other microorganisms that enter the vehicle through the air conditioning system, thereby improving in-vehicle air quality and protecting the health of passengers.

[0003] Currently, the main materials used in air filter cartridges on the market include: Antibacterial materials: Filter cartridges are made with materials containing silver ions or other antibacterial components, which can inhibit bacterial growth. Activated carbon layer: Some high-end filter cartridges contain an activated carbon layer, which not only absorbs odors but also adsorbs and kills some bacteria. Nanotechnology: Some filter cartridges use nanotechnology to enhance their antibacterial properties; for example, nano-silver particles can adhere to the filter fibers, continuously releasing antibacterial substances. Electrostatic effect: Some filter cartridges utilize the electrostatic effect to capture tiny particles in the air, including bacteria, preventing them from entering the vehicle. HEPA filtration: High-performance particulate air filters (HEPA) can filter out extremely fine particles, including bacteria and viruses.

[0004] However, the antibacterial effect of commercially available automotive air conditioning filters is not ideal. Therefore, there is an urgent need for an automotive air conditioning filter that can inhibit bacteria and its preparation method. Summary of the Invention

[0005] The purpose of this invention is to provide an automotive air conditioning filter element capable of inhibiting bacteria and its preparation method.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing an automotive air conditioning filter element capable of inhibiting bacteria, the method comprising the following steps: (1) Add aluminum silicate to water and stir at room temperature for 1-2 hours to obtain a dispersion. Add nano zinc oxide and hexadecyltrimethylammonium bromide to water and stir at room temperature for 0.5-1 hours. Then add them to the dispersion. Adjust the pH value to neutral with 4-6wt% citric acid aqueous solution. Heat to 60-80℃ and stir. Cool and filter. Wash the filter cake with water 3-4 times. Dry at 85-90℃ for 3-4 hours to obtain modified nano zinc oxide. The modified nano zinc oxide consists of 3-4 parts aluminum silicate, 1-1.5 parts nano zinc oxide, and 0.4-0.6 parts hexadecyltrimethylammonium bromide by weight. (2) Add modified nano zinc oxide to N,N-dimethylacetamide and ultrasonically disperse for 0.5-1.5 hours. Add modified polypropylene resin, KH550 and modified filler and mix. Stir at room temperature and melt-spun through a meltblown spinning machine to obtain composite meltblown fabric. The composition by weight is 10-12 parts modified nano zinc oxide, 80-90 parts N,N-dimethylacetamide, 30-40 parts modified polypropylene resin, 1-2 parts KH550 and 7-10 parts modified filler. The modified polypropylene resin contains 2-4% by weight of modified titanium dioxide, 70-80% by weight of propylene polymer and the balance of styrene polymer. (3) A composite meltblown fabric and two 3mm thick activated carbon fiber felt fabrics are bonded together with hot melt adhesive. The activated carbon fiber felt fabrics are bonded together with hot melt adhesive. Then, a composite meltblown fabric is bonded to the topmost activated carbon fiber felt fabric with hot melt adhesive. Finally, hot pressing, cold air shaping, folding, cutting and sealing are performed to obtain the antibacterial automotive air conditioning filter.

[0007] Furthermore, the preparation method of the modified polypropylene resin is as follows: (1) Under nitrogen protection, add 2-3% of the weight of modified titanium dioxide of polypropylene to 30-40% of the weight of styrene of polypropylene, stir to make the modified titanium dioxide evenly dispersed, and then add 0.5-1% of the weight of polypropylene of organic peroxide initiator. (2) Styrene containing organic peroxide initiator and modified titanium dioxide is uniformly absorbed into polypropylene powder under nitrogen protection. The mixture is preheated at 60-65℃ for 1-2 hours, then stirred at 130-135℃ for 2-3 hours. The reaction is terminated and cooled to room temperature. After adding antioxidant, the mixture is granulated to obtain modified polypropylene resin.

[0008] Furthermore, the organic peroxide initiator is tert-butyl peroxide or ditert-butyl peroxide.

[0009] Furthermore, the modified titanium dioxide is prepared by adding hexadecyltrimethylammonium bromide and methacryloyloxyethyltrimethylammonium chloride in a weight ratio of 1:2 to 3 to a titanium dioxide solution of 3% by weight. After stirring at 75-80℃ for 4-5 hours, the mixture is cooled, allowed to stand, filtered, washed with water until the precipitate is free of halide ions, dried, and ground into powder of less than 200 mesh to obtain modified titanium dioxide.

[0010] Furthermore, the method for preparing the modified filler is as follows: S1. Preparation of modified carboxymethyl carbon nanotubes: (1) KH560 and carboxymethyl carbon nanotubes were mixed together and placed in a sealed container to prevent air from entering. Then, they were sonicated. After completion, an organic solvent was added to obtain a mixture. (2) Stir the mixture in step (1) under oil bath heating conditions, then centrifuge to remove the supernatant, wash away the residue in the obtained solid product, and freeze-dry the solid product in liquid nitrogen to obtain modified carboxymethyl carbon nanotubes. Preparation of S2, carboxymethyl carbon nanotubes: (3) Prepare an alcohol solution of the modified carboxymethyl carbon nanotubes, and then add an aqueous solution of nano-titanium dioxide dropwise to the alcohol solution of the modified carboxymethyl carbon nanotubes and stir under oil bath heating conditions. (4) Then centrifuge to remove the supernatant, wash away the residue in the obtained solid product, and freeze-dry the solid product in liquid nitrogen to obtain the modified filler.

[0011] Furthermore, the content of titanium dioxide is 0.03-0.08% of the mass of carboxymethyl carbon nanotubes.

[0012] Furthermore, the mass ratio of the modified carboxymethyl carbon nanotubes to titanium dioxide is 10:1-3; Furthermore, the addition ratio of KH560, carboxymethyl carbon nanotubes, and organic solvent is: 0.6-1.5g: 0.07-0.13g: 30-60ml.

[0013] The present invention also provides an automotive air conditioning filter element prepared by the aforementioned method that can inhibit bacteria.

[0014] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: 1. This invention uses modified nano-zinc oxide. Nano-zinc oxide itself has excellent antibacterial properties because it can release zinc ions. Zinc ions can destroy bacterial cell membranes, interfere with bacterial metabolism, and lead to bacterial death. Aluminum silicate, as an inorganic material, can provide a stable carrier structure, allowing nano-zinc oxide to be more uniformly dispersed in the medium, thus improving the stability of nano-zinc oxide. Simultaneously, aluminum silicate can also enhance the physical strength and durability of the filter element. Hexadecyltrimethylammonium bromide (CTAB): CTAB is a cationic surfactant with good dispersing and stabilizing effects, enabling nano-zinc oxide particles to be better dispersed in water, forming a stable suspension. CTAB also has certain antibacterial activity, which can enhance the overall antibacterial effect of the filter element. The modified nano-zinc oxide prepared in this invention can improve antibacterial performance mainly because of the inherent antibacterial properties of nano-zinc oxide, as well as the enhanced stability and antibacterial effect through interaction with other materials. Such a filter element can effectively inhibit bacterial growth in automotive air conditioning systems and improve in-vehicle air quality.

[0015] 2. The modified polypropylene resin of this invention can improve the antibacterial properties of automotive filter elements. The modified titanium dioxide exhibits excellent antibacterial properties because it can release free radicals with antibacterial effects, especially hydroxyl radicals and superoxide anion radicals. These free radicals can damage bacterial cell membranes, interfere with bacterial metabolism, and thus inhibit bacterial growth. By adding surfactants such as hexadecyltrimethylammonium bromide (CTAB) and methacryloyloxyethyltrimethylammonium chloride (DMOAC), the surface properties of the modified titanium dioxide are altered, making it easier to combine with the polypropylene matrix and disperse more uniformly within it, thereby improving the material's antibacterial properties. Stirring under nitrogen protection to uniformly disperse the modified titanium dioxide within the polypropylene matrix helps ensure its uniform distribution throughout the filter element material, thus improving the consistency of the antibacterial effect. Modified polypropylene resin enhances the antibacterial properties of automotive filters through a combination of factors: the antibacterial properties of modified titanium dioxide, the modification effect of surfactants, the cross-linking effect of organic peroxide initiators, the uniform dispersion of modified titanium dioxide in the polypropylene matrix, and the protective effect of antioxidants. Such filters effectively inhibit bacterial growth in automotive air conditioning systems, improving in-vehicle air quality. Detailed Implementation

[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] Example 1 This embodiment provides a method for preparing an automotive air conditioning filter element capable of inhibiting bacteria, the preparation method comprising the following steps: (1) Add aluminum silicate to water and stir at room temperature for 1 hour to obtain a dispersion. Add nano zinc oxide and hexadecyltrimethylammonium bromide to water and stir at room temperature for 1 hour. Then add them to the dispersion. Adjust the pH value to neutral with 4wt% citric acid aqueous solution. Heat to 80℃ and stir. Cool and filter. Wash the filter cake with water 3 times. Dry at 90℃ for 3 hours to obtain modified nano zinc oxide. The composition by weight is 4 parts aluminum silicate, 1 part nano zinc oxide and 0.6 parts hexadecyltrimethylammonium bromide. (2) Add modified nano zinc oxide to N,N-dimethylacetamide, ultrasonically disperse for 0.5 hours, add modified polypropylene resin, KH550 and modified filler and mix, stir at room temperature, and melt-spun through a meltblown spinning machine to obtain composite meltblown fabric; by weight, it is 12 parts modified nano zinc oxide, 80 parts N,N-dimethylacetamide, 40 parts modified polypropylene resin, 2 parts KH550 and 10 parts modified filler; The modified polypropylene resin contains 4% by weight of modified titanium dioxide, 70% by weight of propylene polymer and the balance of styrene polymer. (3) A composite meltblown fabric and two 3mm thick activated carbon fiber felt fabrics are bonded together with hot melt adhesive. The activated carbon fiber felt fabrics are bonded together with hot melt adhesive. Then, a composite meltblown fabric is bonded to the topmost activated carbon fiber felt fabric with hot melt adhesive. Finally, hot pressing, cold air shaping, folding, cutting and sealing are performed to obtain the antibacterial automotive air conditioning filter.

[0018] The preparation method of modified polypropylene resin is as follows: (1) Under nitrogen protection, 3% of the weight of modified titanium dioxide of polypropylene was added to 30% of the weight of styrene of polypropylene, and stirred to make the modified titanium dioxide evenly dispersed. Then, 1% of the weight of organic peroxide initiator of polypropylene was added. (2) Styrene containing organic peroxide initiator and modified titanium dioxide was uniformly absorbed into polypropylene powder under nitrogen protection. The mixture was preheated at 60°C for 1 hour, then stirred at 135°C for 2 hours to terminate the reaction. The mixture was then cooled to room temperature, and an antioxidant was added before granulation to obtain modified polypropylene resin.

[0019] The organic peroxide initiator is tert-butyl peroxide or ditert-butyl peroxide.

[0020] The modified titanium dioxide is prepared by adding hexadecyltrimethylammonium bromide and methacryloyloxyethyltrimethylammonium chloride in a weight ratio of 1:2 to a titanium dioxide solution of 3% by weight. After stirring at 80°C for 4 hours, the mixture is cooled, allowed to stand, filtered, washed with water until the precipitate is free of halide ions, dried, and ground into powder with a mesh size of less than 200 to obtain modified titanium dioxide.

[0021] The modified filler is prepared by: S1. Preparation of modified carboxymethyl carbon nanotubes: (1) KH560 and carboxymethyl carbon nanotubes were mixed together and placed in a sealed container to prevent air from entering. Then, they were sonicated. After completion, an organic solvent was added to obtain a mixture. (2) Stir the mixture in step (1) under oil bath heating conditions, then centrifuge to remove the supernatant, wash away the residue in the obtained solid product, and freeze-dry the solid product in liquid nitrogen to obtain modified carboxymethyl carbon nanotubes. Preparation of S2, carboxymethyl carbon nanotubes: (3) Prepare an alcohol solution of the modified carboxymethyl carbon nanotubes, and then add an aqueous solution of nano-titanium dioxide dropwise to the alcohol solution of the modified carboxymethyl carbon nanotubes and stir under oil bath heating conditions. (4) Then centrifuge to remove the supernatant, wash away the residue in the obtained solid product, and freeze-dry the solid product in liquid nitrogen to obtain the modified filler.

[0022] The content of titanium dioxide is 0.08% of the mass of carboxymethyl carbon nanotubes.

[0023] The mass ratio of the modified carboxymethyl carbon nanotubes to titanium dioxide is 10:3; The addition ratio of KH560, carboxymethyl carbon nanotubes, and organic solvent is 1.5g:0.07g:60ml.

[0024] Comparative Example 1 The difference between this comparative example and Example 1 is that the zinc oxide is not modified.

[0025] A method for preparing an automotive air conditioning filter element capable of inhibiting bacteria, the method comprising the following steps: (1) Add nano zinc oxide to N,N-dimethylacetamide, ultrasonically disperse for 0.5 hours, add modified polypropylene resin, KH550 and modified filler and mix, stir at room temperature, and melt-spun through a meltblown spinning machine to obtain composite meltblown fabric; by weight, it is 12 parts modified nano zinc oxide, 80 parts N,N-dimethylacetamide, 40 parts modified polypropylene resin, 2 parts KH550 and 10 parts modified filler; The modified polypropylene resin contains 4% by weight of modified titanium dioxide, 70% by weight of propylene polymer and the balance of styrene polymer. (2) A composite meltblown fabric and two 3mm thick activated carbon fiber felt fabrics are bonded together with hot melt adhesive. The activated carbon fiber felt fabrics are bonded together with hot melt adhesive. Then, a composite meltblown fabric is bonded to the topmost activated carbon fiber felt fabric with hot melt adhesive. Finally, hot pressing, cold air shaping, folding, cutting and sealing are performed to obtain the antibacterial automotive air conditioning filter.

[0026] The preparation method of modified polypropylene resin is as follows: (1) Under nitrogen protection, 3% of the weight of modified titanium dioxide of polypropylene was added to 30% of the weight of styrene of polypropylene, and stirred to make the modified titanium dioxide evenly dispersed. Then, 1% of the weight of organic peroxide initiator of polypropylene was added. (2) Styrene containing organic peroxide initiator and modified titanium dioxide was uniformly absorbed into polypropylene powder under nitrogen protection. The mixture was preheated at 60°C for 1 hour, then stirred at 135°C for 2 hours to terminate the reaction. The mixture was then cooled to room temperature, and an antioxidant was added before granulation to obtain modified polypropylene resin.

[0027] The organic peroxide initiator is tert-butyl peroxide or ditert-butyl peroxide.

[0028] The modified titanium dioxide is prepared by adding hexadecyltrimethylammonium bromide and methacryloyloxyethyltrimethylammonium chloride in a weight ratio of 1:2 to a titanium dioxide solution of 3% by weight. After stirring at 80°C for 4 hours, the mixture is cooled, allowed to stand, filtered, washed with water until the precipitate is free of halide ions, dried, and ground into powder with a mesh size of less than 200 to obtain modified titanium dioxide.

[0029] The modified filler is prepared by: S1. Preparation of modified carboxymethyl carbon nanotubes: (1) KH560 and carboxymethyl carbon nanotubes were mixed together and placed in a sealed container to prevent air from entering. Then, they were sonicated. After completion, an organic solvent was added to obtain a mixture. (2) Stir the mixture in step (1) under oil bath heating conditions, then centrifuge to remove the supernatant, wash away the residue in the obtained solid product, and freeze-dry the solid product in liquid nitrogen to obtain modified carboxymethyl carbon nanotubes. Preparation of S2, carboxymethyl carbon nanotubes: (3) Prepare an alcohol solution of the modified carboxymethyl carbon nanotubes, and then add an aqueous solution of nano-titanium dioxide dropwise to the alcohol solution of the modified carboxymethyl carbon nanotubes and stir under oil bath heating conditions. (4) Then centrifuge to remove the supernatant, wash away the residue in the obtained solid product, and freeze-dry the solid product in liquid nitrogen to obtain the modified filler.

[0030] The content of titanium dioxide is 0.08% of the mass of carboxymethyl carbon nanotubes.

[0031] The mass ratio of the modified carboxymethyl carbon nanotubes to titanium dioxide is 10:3; The addition ratio of KH560, carboxymethyl carbon nanotubes, and organic solvent is 1.5g:0.07g:60ml.

[0032] Comparative Example 2 The difference between this comparative example and Example 1 is that the polypropylene resin is not modified.

[0033] A method for preparing an automotive air conditioning filter element capable of inhibiting bacteria, the method comprising the following steps: (1) Add aluminum silicate to water and stir at room temperature for 1 hour to obtain a dispersion. Add nano zinc oxide and hexadecyltrimethylammonium bromide to water and stir at room temperature for 1 hour. Then add them to the dispersion. Adjust the pH value to neutral with 4wt% citric acid aqueous solution. Heat to 80℃ and stir. Cool and filter. Wash the filter cake with water 3 times. Dry at 90℃ for 3 hours to obtain modified nano zinc oxide. The composition by weight is 4 parts aluminum silicate, 1 part nano zinc oxide and 0.6 parts hexadecyltrimethylammonium bromide. (2) Add modified nano zinc oxide to N,N-dimethylacetamide, ultrasonically disperse for 0.5 hours, add polypropylene resin, KH550 and modified filler and mix, stir at room temperature, and melt-spun through a meltblown spinning machine to obtain composite meltblown fabric; by weight, it is 12 parts modified nano zinc oxide, 80 parts N,N-dimethylacetamide, 40 parts modified polypropylene resin, 2 parts KH550 and 10 parts modified filler; (3) A composite meltblown fabric and two 3mm thick activated carbon fiber felt fabrics are bonded together with hot melt adhesive. The activated carbon fiber felt fabrics are bonded together with hot melt adhesive. Then, a composite meltblown fabric is bonded to the topmost activated carbon fiber felt fabric with hot melt adhesive. Finally, hot pressing, cold air shaping, folding, cutting and sealing are performed to obtain the antibacterial automotive air conditioning filter.

[0034] The modified filler is prepared by: S1. Preparation of modified carboxymethyl carbon nanotubes: (1) KH560 and carboxymethyl carbon nanotubes were mixed together and placed in a sealed container to prevent air from entering. Then, they were sonicated. After completion, an organic solvent was added to obtain a mixture. (2) Stir the mixture in step (1) under oil bath heating conditions, then centrifuge to remove the supernatant, wash away the residue in the obtained solid product, and freeze-dry the solid product in liquid nitrogen to obtain modified carboxymethyl carbon nanotubes. Preparation of S2, carboxymethyl carbon nanotubes: (3) Prepare an alcohol solution of the modified carboxymethyl carbon nanotubes, and then add an aqueous solution of nano-titanium dioxide dropwise to the alcohol solution of the modified carboxymethyl carbon nanotubes and stir under oil bath heating conditions. (4) Then centrifuge to remove the supernatant, wash away the residue in the obtained solid product, and freeze-dry the solid product in liquid nitrogen to obtain the modified filler.

[0035] The content of titanium dioxide is 0.08% of the mass of carboxymethyl carbon nanotubes.

[0036] The mass ratio of the modified carboxymethyl carbon nanotubes to titanium dioxide is 10:3; The addition ratio of KH560, carboxymethyl carbon nanotubes, and organic solvent is 1.5g:0.07g:60ml.

[0037] Comparative Example 3 The difference between this comparative example and Example 1 is that the modified filler was replaced with nano-titanium dioxide.

[0038] A method for preparing an automotive air conditioning filter element capable of inhibiting bacteria, the method comprising the following steps: (1) Add aluminum silicate to water and stir at room temperature for 1 hour to obtain a dispersion. Add nano zinc oxide and hexadecyltrimethylammonium bromide to water and stir at room temperature for 1 hour. Then add them to the dispersion. Adjust the pH value to neutral with 4wt% citric acid aqueous solution. Heat to 80℃ and stir. Cool and filter. Wash the filter cake with water 3 times. Dry at 90℃ for 3 hours to obtain modified nano zinc oxide. The composition by weight is 4 parts aluminum silicate, 1 part nano zinc oxide and 0.6 parts hexadecyltrimethylammonium bromide. (2) Add modified nano zinc oxide to N,N-dimethylacetamide, ultrasonically disperse for 0.5 hours, add modified polypropylene resin, KH550 and nano titanium dioxide and mix, stir at room temperature, and melt-spun through a meltblown spinning machine to obtain composite meltblown fabric; by weight, it is 12 parts modified nano zinc oxide, 80 parts N,N-dimethylacetamide, 40 parts modified polypropylene resin, 2 parts KH550 and 10 parts modified filler; The modified polypropylene resin contains 4% by weight of modified titanium dioxide, 70% by weight of propylene polymer and the balance of styrene polymer. (3) A composite meltblown fabric and two 3mm thick activated carbon fiber felt fabrics are bonded together with hot melt adhesive. The activated carbon fiber felt fabrics are bonded together with hot melt adhesive. Then, a composite meltblown fabric is bonded to the topmost activated carbon fiber felt fabric with hot melt adhesive. Finally, hot pressing, cold air shaping, folding, cutting and sealing are performed to obtain the antibacterial automotive air conditioning filter.

[0039] The preparation method of modified polypropylene resin is as follows: (1) Under nitrogen protection, 3% of the weight of modified titanium dioxide of polypropylene was added to 30% of the weight of styrene of polypropylene, and stirred to make the modified titanium dioxide evenly dispersed. Then, 1% of the weight of organic peroxide initiator of polypropylene was added. (2) Styrene containing organic peroxide initiator and modified titanium dioxide was uniformly absorbed into polypropylene powder under nitrogen protection. The mixture was preheated at 60°C for 1 hour, then stirred at 135°C for 2 hours to terminate the reaction. The mixture was then cooled to room temperature, and an antioxidant was added before granulation to obtain modified polypropylene resin.

[0040] The organic peroxide initiator is tert-butyl peroxide or ditert-butyl peroxide.

[0041] The modified titanium dioxide is prepared by adding hexadecyltrimethylammonium bromide and methacryloyloxyethyltrimethylammonium chloride in a weight ratio of 1:2 to a titanium dioxide solution of 3% by weight. After stirring at 80°C for 4 hours, the mixture is cooled, allowed to stand, filtered, washed with water until the precipitate is free of halide ions, dried, and ground into powder with a mesh size of less than 200 to obtain modified titanium dioxide.

[0042] Comparative Example 4 The difference between this comparative example and Example 1 is that the preparation method of the modified filler is different. A method for preparing an automotive air conditioning filter element capable of inhibiting bacteria, the method comprising the following steps: (1) Add aluminum silicate to water and stir at room temperature for 1 hour to obtain a dispersion. Add nano zinc oxide and hexadecyltrimethylammonium bromide to water and stir at room temperature for 1 hour. Then add them to the dispersion. Adjust the pH value to neutral with 4wt% citric acid aqueous solution. Heat to 80℃ and stir. Cool and filter. Wash the filter cake with water 3 times. Dry at 90℃ for 3 hours to obtain modified nano zinc oxide. The composition by weight is 4 parts aluminum silicate, 1 part nano zinc oxide and 0.6 parts hexadecyltrimethylammonium bromide. (2) Add modified nano zinc oxide to N,N-dimethylacetamide, ultrasonically disperse for 0.5 hours, add modified polypropylene resin, KH550 and modified filler and mix, stir at room temperature, and melt-spun through a meltblown spinning machine to obtain composite meltblown fabric; by weight, it is 12 parts modified nano zinc oxide, 80 parts N,N-dimethylacetamide, 40 parts modified polypropylene resin, 2 parts KH550 and 10 parts modified filler; The modified polypropylene resin contains 4% by weight of modified titanium dioxide, 70% by weight of propylene polymer and the balance of styrene polymer. (3) A composite meltblown fabric and two 3mm thick activated carbon fiber felt fabrics are bonded together with hot melt adhesive. The activated carbon fiber felt fabrics are bonded together with hot melt adhesive. Then, a composite meltblown fabric is bonded to the topmost activated carbon fiber felt fabric with hot melt adhesive. Finally, hot pressing, cold air shaping, folding, cutting and sealing are performed to obtain the antibacterial automotive air conditioning filter.

[0043] The preparation method of modified polypropylene resin is as follows: (1) Under nitrogen protection, 3% of the weight of modified titanium dioxide of polypropylene was added to 30% of the weight of styrene of polypropylene, and stirred to make the modified titanium dioxide evenly dispersed. Then, 1% of the weight of organic peroxide initiator of polypropylene was added. (2) Styrene containing organic peroxide initiator and modified titanium dioxide was uniformly absorbed into polypropylene powder under nitrogen protection. The mixture was preheated at 60°C for 1 hour, then stirred at 135°C for 2 hours to terminate the reaction. The mixture was then cooled to room temperature, and an antioxidant was added before granulation to obtain modified polypropylene resin.

[0044] The organic peroxide initiator is tert-butyl peroxide or ditert-butyl peroxide.

[0045] The modified titanium dioxide is prepared by adding hexadecyltrimethylammonium bromide and methacryloyloxyethyltrimethylammonium chloride in a weight ratio of 1:2 to a titanium dioxide solution of 3% by weight. After stirring at 80°C for 4 hours, the mixture is cooled, allowed to stand, filtered, washed with water until the precipitate is free of halide ions, dried, and ground into powder with a mesh size of less than 200 to obtain modified titanium dioxide.

[0046] The modified filler is prepared by: S1. Preparation of modified graphene oxide: (1) KH560 and graphene oxide are mixed together and placed in a sealed container to prevent air from entering. Then, they are sonicated. After completion, an organic solvent is added to obtain a mixture. (2) Stir the mixture in step (1) under oil bath heating conditions, then centrifuge to remove the supernatant, wash away the residue in the obtained solid product, and freeze-dry the solid product in liquid nitrogen to obtain modified graphene oxide. S2. Preparation of amphiphilic graphene oxide: (3) Prepare an alcohol solution of the modified graphene oxide as described above, and then add an aqueous solution of nano-titanium dioxide dropwise to the alcohol solution of the modified graphene oxide, and stir under oil bath heating conditions. (4) Then centrifuge to remove the supernatant, wash away the residue in the obtained solid product, and freeze-dry the solid product in liquid nitrogen to obtain the modified filler.

[0047] The content of titanium dioxide is 0.08% of the mass of graphene oxide.

[0048] The mass ratio of the modified graphene oxide to titanium dioxide is 10:3; The addition ratio of KH560, graphene oxide, and organic solvent is 1.5g:0.07g:60ml.

[0049] Performance testing The filter elements prepared in Example 1 and Comparative Examples 1-4 were subjected to performance tests.

[0050] The test was conducted according to the national standard GB / T20944.2-2007 "Evaluation of Antimicrobial Properties of Textiles" Part 2 - Absorption Method. The test strains were Escherichia coli ATCC35150 and Staphylococcus aureus ATCC27659, and the concentration of the prepared sample bacterial solution was 10. 7 CFU / mL.

[0051] The composite meltblown fabric was cut into 10cm×10cm samples. Six samples were reserved for testing in each example. Three samples were used as a group. A control sample group was also set up. The control group consisted of three ordinary non-woven fabric samples. The test data were taken as the average value.

[0052] Inhibition rate = (Ct - Tt / Ct) × 100 Where: Ct - the average number of bacteria measured after the control sample is inoculated and cultured for 24 hours; Tt - the average number of bacteria measured after the test sample is inoculated and cultured for 24 hours.

[0053] The results are shown in Table 1.

[0054] Table 1 Performance Test Results

[0055] The performance test results above show that Example 1 exhibits the most outstanding antibacterial effect, mainly due to the synergistic effect of the components. The comparative example, however, failed to employ the necessary technical solutions, resulting in significantly inferior performance compared to the examples. These experimental results further demonstrate the importance of the technical solutions defined in this invention for its technical effectiveness.

[0056] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an automotive air conditioning filter element capable of inhibiting bacteria, characterized in that, The preparation method includes the following steps: (1) Add aluminum silicate to water and stir at room temperature for 1-2 hours to obtain a dispersion. Add nano zinc oxide and hexadecyltrimethylammonium bromide to water and stir at room temperature for 0.5-1 hours. Then add them to the dispersion. Adjust the pH value to neutral with 4-6wt% citric acid aqueous solution. Heat to 60-80℃ and stir. Cool and filter. Wash the filter cake with water 3-4 times. Dry at 85-90℃ for 3-4 hours to obtain modified nano zinc oxide. (2) Add modified nano zinc oxide to N,N-dimethylacetamide and ultrasonically disperse for 0.5-1.5 hours. Add modified polypropylene resin, KH550 and modified filler and mix. Stir at room temperature and melt-spun through a meltblown spinning machine to obtain composite meltblown fabric. The composition by weight is 10-12 parts modified nano zinc oxide, 80-90 parts N,N-dimethylacetamide, 30-40 parts modified polypropylene resin, 1-2 parts KH550 and 7-10 parts modified filler. The modified polypropylene resin contains 2-4% by weight of modified titanium dioxide, 70-80% by weight of propylene polymer and the balance of styrene polymer. (3) A composite meltblown fabric and two 3mm thick activated carbon fiber felt fabrics are bonded together with hot melt adhesive. The activated carbon fiber felt fabrics are bonded together with hot melt adhesive. Then, a composite meltblown fabric is bonded to the topmost activated carbon fiber felt fabric with hot melt adhesive. Finally, hot pressing, cold air shaping, folding, cutting and sealing are performed to obtain the antibacterial automotive air conditioning filter.

2. The method for preparing an automotive air conditioning filter element capable of inhibiting bacteria according to claim 1, characterized in that, The preparation method of modified polypropylene resin is as follows: (1) Under nitrogen protection, add 2-3% of the weight of modified titanium dioxide of polypropylene to 30-40% of the weight of styrene of polypropylene, stir to make the modified titanium dioxide evenly dispersed, and then add 0.5-1% of the weight of polypropylene of organic peroxide initiator. (2) Styrene containing organic peroxide initiator and modified titanium dioxide is uniformly absorbed into polypropylene powder under nitrogen protection. The mixture is preheated at 60-65℃ for 1-2 hours, then stirred at 130-135℃ for 2-3 hours. The reaction is terminated and cooled to room temperature. After adding antioxidant, the mixture is granulated to obtain modified polypropylene resin.

3. The method for preparing an automotive air conditioning filter element capable of inhibiting bacteria according to claim 2, characterized in that, The organic peroxide initiator is tert-butyl peroxide or ditert-butyl peroxide.

4. The method for preparing an automotive air conditioning filter element capable of inhibiting bacteria according to claim 2, characterized in that, The modified titanium dioxide is prepared by adding hexadecyltrimethylammonium bromide and methacryloyloxyethyltrimethylammonium chloride in a weight ratio of 1:2 to 3 to a titanium dioxide solution of 3% by weight. After stirring at 75-80℃ for 4-5 hours, the mixture is cooled, allowed to stand, filtered, and washed with water until the precipitate is free of halide ions. After drying, it is ground into powder with a mesh size of less than 200 to obtain modified titanium dioxide.

5. The method for preparing an automotive air conditioning filter element capable of inhibiting bacteria according to claim 1, characterized in that, The modified filler is prepared by: S1. Preparation of modified carboxymethyl carbon nanotubes: (1) KH560 and carboxymethyl carbon nanotubes were mixed together and placed in a sealed container to prevent air from entering. Then, they were sonicated. After completion, an organic solvent was added to obtain a mixture. (2) Stir the mixture in step (1) under oil bath heating conditions, then centrifuge to remove the supernatant, wash away the residue in the obtained solid product, and freeze-dry the solid product in liquid nitrogen to obtain modified carboxymethyl carbon nanotubes. Preparation of S2, carboxymethyl carbon nanotubes: (3) Prepare an alcohol solution of the modified carboxymethyl carbon nanotubes, and then add an aqueous solution of nano-titanium dioxide dropwise to the alcohol solution of the modified carboxymethyl carbon nanotubes and stir under oil bath heating conditions. (4) Then centrifuge to remove the supernatant, wash away the residue in the obtained solid product, and freeze-dry the solid product in liquid nitrogen to obtain the modified filler.

6. The method for preparing an automotive air conditioning filter element capable of inhibiting bacteria according to claim 5, characterized in that, The content of titanium dioxide is 0.03-0.08% of the mass of carboxymethyl carbon nanotubes.

7. The method for preparing an automotive air conditioning filter element capable of inhibiting bacteria according to claim 5, characterized in that, The mass ratio of the modified carboxymethyl carbon nanotubes to titanium dioxide is 10:1-3.

8. The method for preparing an automotive air conditioning filter element capable of inhibiting bacteria according to claim 5, characterized in that, The addition ratio of KH560, carboxymethyl carbon nanotubes, and organic solvent is: 0.6-1.5g: 0.07-0.13g: 30-60ml.

9. The method for preparing an automotive air conditioning filter element capable of inhibiting bacteria according to claim 1, characterized in that, The composition by weight is 3-4 parts aluminum silicate, 1-1.5 parts nano zinc oxide, and 0.4-0.6 parts cetyltrimethylammonium bromide.

10. A filter element for automotive air conditioning that can inhibit bacteria, prepared by the method according to any one of claims 1-9.

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