An air filter material and its preparation method

Abstract

This application relates to the field of filter material technology, mainly to an air filter material and its preparation method. An air filter material comprises the following components: wood pulp fiber: 60-70 parts by weight; modified PAN nanofibers: 10-20 parts by weight; modified PTFE emulsion: 1-3 parts by weight; modified PLA: 5-10 parts by weight; chitosan: 0.1-1 parts by weight; sodium polyacrylate: 0.01-0.1 parts by weight. The preparation method of the air filter material includes the following steps: soaking wood pulp fiber in water and pulping; mixing the pulped wood pulp fiber, modified PAN nanofibers, modified PTFE emulsion, modified PLA, chitosan, and sodium polyacrylate to obtain a mixed pulp; using the mixed pulp for papermaking; drying and calendering to obtain the air filter material. The air filter material provided by this application, while ensuring high filtration performance, also possesses high moisture resistance and strong antibacterial effects.

Description

Technical Field

[0001] This application relates to the field of filter material technology, and mainly to an air filter material and its preparation method. Background Technology

[0002] Air filtration materials are the core components of air purification systems, responsible for intercepting particulate matter, adsorbing harmful gases, and inhibiting the growth of microorganisms. They are widely used in fields with stringent air quality requirements, such as precision manufacturing, medical and health care, and environmental engineering. Traditional air filtration materials mainly consist of glass fiber filter paper, synthetic fiber filter media, and activated carbon composite materials. They achieve air purification through mechanisms such as physical interception, electrostatic adsorption, or chemical adsorption, and can meet basic filtration needs under normal operating conditions.

[0003] However, in terms of filtration efficiency, especially for fine particulate matter such as PM2.5, the filtration efficiency of traditional filter paper needs improvement. Some filter papers use a single fiber structure, which has limited ability to intercept fine particles, allowing pollutants to easily penetrate and affecting air purification. At the same time, filter paper has a limited dust holding capacity, making it prone to clogging, leading to a rapid decline in filtration efficiency and requiring frequent replacement, increasing usage costs and maintenance workload. Furthermore, the structural design of some filter papers is not optimized, resulting in greater airflow resistance and affecting air circulation efficiency.

[0004] Furthermore, regarding antibacterial and anti-mold properties, air filter paper is prone to bacterial and mold growth during use, leading to secondary pollution, affecting air quality, and potentially posing a threat to human health. Existing filter paper has poor antibacterial and anti-mold properties and cannot effectively inhibit the growth of microorganisms.

[0005] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this application is to provide an air filter material and a method for preparing the same, with the aim of improving the performance of the air filter material.

[0007] The technical solution of this application is as follows:

[0008] An air filter material comprising the following components:

[0009] Wood pulp fiber: 60-70 parts by weight;

[0010] Modified PAN nanofibers: 10-20 parts by weight;

[0011] Modified PTFE emulsion: 1-3 parts by weight;

[0012] Modified PLA: 5-10 parts by weight;

[0013] Chitosan: 0.1-1 parts by weight;

[0014] Sodium polyacrylate: 0.01-0.1 parts by weight.

[0015] Furthermore, the preparation of modified PAN nanofibers includes the following steps:

[0016] PAN nanofibers, polar solvents, and PEG monomethyl ether are mixed and reacted at 55-65℃ for 4-6 hours under inert gas protection.

[0017] After washing and drying, modified PAN nanofibers are obtained.

[0018] Furthermore, the amount of polar solvent used is 3-6 times the weight of the PAN nanofibers;

[0019] The amount of PEG monomethyl ether used is 8-12% of the weight of PAN nanofibers.

[0020] Furthermore, the preparation of the modified PTFE emulsion includes the following steps: dodecyltrimethylammonium chloride is mixed and stirred with PTFE emulsion to obtain the modified PTFE emulsion.

[0021] Furthermore, the amount of dodecyltrimethylammonium chloride used is 0.1-1% of the solid content of the PTFE emulsion.

[0022] Furthermore, the preparation of modified PLA includes the following steps: PLA, dichloromethane, isocyanate, and catalyst are mixed and heated to 80-85℃ under inert gas protection for 2-3 hours.

[0023] After precipitation and drying, modified PLA is obtained.

[0024] Furthermore, the amount of isocyanate used is 0.5-2% of the weight of PLA, and the amount of catalyst used is 0.01-0.1% of the weight of PLA.

[0025] Further, PLA is dissolved in dichloromethane to prepare a PLA solution with a concentration of 8-12%; then it is mixed with isocyanate and catalyst, and heated to 80-85℃ under inert gas protection for 2-3 hours.

[0026] This application also provides a method for preparing an air filter material, comprising the following steps:

[0027] Wood pulp fibers are soaked in water and pulped to 35-40°SR;

[0028] The pulped wood pulp fibers, modified PAN nanofibers, modified PTFE emulsion, modified PLA, chitosan, and sodium polyacrylate are mixed to obtain a mixed pulp.

[0029] Papermaking is carried out using mixed pulp; after drying and calendering, air filter material is obtained.

[0030] Furthermore, the modified PAN nanofibers participate in the mixing in the form of a modified PAN nanofiber suspension; the modified PAN nanofiber suspension includes modified PAN nanofibers and water;

[0031] Chitosan participates in the mixing in the form of a chitosan solution; the chitosan solution includes chitosan and water.

[0032] The air filter material provided in this application, while ensuring high filtration performance, also possesses high moisture resistance and strong antibacterial properties. Specifically:

[0033] Wood pulp fibers are pulped to form a large-pore framework, providing low-resistance channels for airflow. Modified PAN nanofibers are grafted with PEG and ultrasonically dispersed to achieve single-fiber formation, uniformly filling the gaps in the wood pulp network and refining the pores to form a gradient pore structure of "large-pore guidance and small-pore interception." This structure ensures efficient airflow (low initial pressure drop) while enhancing the capture efficiency of PM0.3-PM2.5 particles through the pore gradient. Furthermore, PTFE emulsion is adsorbed onto the surface of PTFE particles through the electrostatic interaction of DTAC, making the emulsion positively charged. The modified PTFE emulsion adheres to the network surface, more effectively generating strong electrostatic adsorption with negatively charged bacteria, viruses, and tiny particles, further enhancing filtration efficiency, especially significantly improving the capture efficiency of charged particles. This forms a dual interception mechanism of pore structure interception and charge adsorption, achieving highly efficient air purification.

[0034] In modified PLA, PLA forms a three-dimensional network structure through cross-linking with isocyanate. Its urethane bonds chemically bond with the hydroxyl groups of wood pulp fibers and the cyano groups of modified PAN nanofibers, forming an interpenetrating "fiber-crosslink network" structure. This structure constructs a dense chemical connection network at the microscopic level, achieving stable connections between fibers through urethane bonds, effectively improving wet strength and water resistance, and preventing paper base swelling and deformation caused by moisture penetration. Simultaneously, the modified PTFE emulsion reduces surface energy through DTAC, and the two work synergistically to form a dual-effect protection system of "hydrophobic barrier - low surface energy." This system not only effectively blocks oily particles (such as oil fumes and droplets) and moisture penetration, but also maintains the integrity of the pore structure through molecular-level barrier action, avoiding pore blockage or structural damage caused by moisture intrusion, ultimately achieving multi-dimensional enhancement of moisture resistance.

[0035] Chitosan disrupts bacterial cell membranes through its cationic properties, directly inhibiting microbial growth. DTAC in the modified PTFE emulsion enhances the antibacterial effect through electrostatic adsorption and chemical antibacterial activity, forming a dual "physical-chemical" antibacterial mechanism. In humid environments, the quaternary ammonium salts in the modified PTFE emulsion continuously exert their chemical antibacterial effect, synergizing with the cationic properties of chitosan, significantly improving the inhibition rate against *Escherichia coli* and *Staphylococcus aureus*. This charge-bio dual-effect synergy not only enhances the inhibitory ability against various microorganisms but also effectively prevents filter paper from becoming moldy, extending its service life and ensuring long-lasting antibacterial performance in complex environments.

[0036] Compared with the prior art, this application has the following beneficial effects:

[0037] 1. Wood pulp fibers, after pulping, form a large-pore framework, providing low-resistance channels for airflow. Modified PAN nanofibers are grafted with PEG and dispersed ultrasonically to achieve single-fiber formation, uniformly filling the gaps in the wood pulp network to form a gradient pore structure of "large-pore guidance and small-pore interception." This structure ensures efficient airflow while enhancing the capture capacity of tiny particles through the pore gradient. PTFE emulsion adsorbs positively charged particles through electrostatic interactions, resulting in strong adsorption with negatively charged particles, forming a dual interception mechanism of pore structure and charge adsorption, achieving highly efficient air purification.

[0038] 2. PLA forms a three-dimensional network structure through isocyanate crosslinking. Its urethane bonds chemically bond with the hydroxyl groups of wood pulp fibers and the cyano groups of modified PAN nanofibers, constructing an interpenetrating "fiber-crosslink network" structure. This structure forms a dense chemically connected network at the microscopic level, enhancing wet strength and water resistance through stable bonding, effectively preventing paper base swelling and deformation caused by moisture penetration. Combined with the low surface energy characteristics of modified PTFE emulsion, a synergistic protective system of hydrophobic barrier and low surface energy is formed, blocking oily particles and moisture penetration while maintaining the integrity of the pore structure, preventing structural damage, and achieving multi-dimensional enhancement of moisture resistance.

[0039] 3. Chitosan disrupts bacterial cell membranes and inhibits microbial growth through its cationic properties; the quaternary ammonium salt in the modified PTFE emulsion enhances the antibacterial effect through electrostatic adsorption and chemical antibacterial activity, forming a dual "physical-chemical" antibacterial mechanism. In humid environments, the quaternary ammonium salt continues to exert its antibacterial effect, synergistically enhancing the inhibitory ability against microorganisms with chitosan, effectively preventing mold growth, extending service life, and ensuring long-lasting antibacterial performance. Detailed Implementation

[0040] To facilitate understanding of this application, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of this application.

[0041] This application provides an air filter material comprising the following components:

[0042] Wood pulp fiber: 60-70 parts by weight;

[0043] Modified PAN nanofibers: 10-20 parts by weight;

[0044] Modified PTFE emulsion: 1-3 parts by weight;

[0045] Modified PLA: 5-10 parts by weight;

[0046] Chitosan: 0.1-1 parts by weight (degree of deacetylation 80-90%);

[0047] Sodium polyacrylate (PAAS): 0.01-0.1 parts by weight.

[0048] This application also provides a method for preparing an air filter material, comprising the following steps:

[0049] Step 1: Soak the wood pulp fibers in water for 24-48 hours, initially disperse them using a high-speed disperser for 20-60 minutes (1000-1500 rpm), and then beat them to 35-40°SR using a pulper.

[0050] Step 2: Prepare modified PAN nanofibers, including the following steps:

[0051] PAN nanofibers (commercially available, purchased from Suzhou Beike Nanotechnology Co., Ltd. in this example) were dispersed in a polar solvent, and PEG monomethyl ether was added to obtain mixture A.

[0052] The amount of polar solvent used is 3-6 times the weight of PAN nanofibers.

[0053] Polar solvents include DMF, DMSO, DMAc, a mixture of acetone and DMF, butyl acetate, butyl propionate, and anisole.

[0054] The amount of PEG monomethyl ether used is 8-12% of the weight of PAN nanofibers.

[0055] Under inert gas protection, mixture A is heated to 55-65℃ and reacted for 4-6 hours.

[0056] After the reaction was completed, the nanofibers were washed with ethanol several times and dried under vacuum for 24-48 hours to obtain the modified PAN nanofibers.

[0057] Step 3: Add the modified PAN nanofibers to deionized water and disperse them using an ultrasonic disruptor for 20-40 minutes (300-400W, intermittent ultrasonication) to prepare a modified PAN nanofiber suspension with a concentration of 0.1-1%.

[0058] Step 4: Prepare the modified PTFE emulsion, including the following steps:

[0059] The PTFE emulsion is diluted with deionized water to a solid content of 3-8% to obtain a diluted PTFE emulsion.

[0060] Dodecyltrimethylammonium chloride was dissolved in deionized water to prepare a 0.1-1% dodecyltrimethylammonium chloride solution.

[0061] The amount of dodecyltrimethylammonium chloride used is 0.1-1% of the solid content of the PTFE emulsion.

[0062] The dodecyltrimethylammonium chloride solution is slowly added to the diluted PTFE emulsion and stirred for 20-60 minutes to fully disperse the dodecyltrimethylammonium chloride in the PTFE emulsion, thus obtaining the modified PTFE emulsion.

[0063] Step 5: Prepare modified PLA, including the following steps:

[0064] Dissolve PLA in dichloromethane to prepare a PLA solution with a concentration of 8-12%.

[0065] Hexamethylene diisocyanate and the catalyst dibutyltin dilaurate were added to the PLA solution to obtain mixture B.

[0066] The amount of HDI used is 0.5-2% of the weight of PLA, and the amount of DBTDL used is 0.01-0.1% of the weight of PLA.

[0067] Under nitrogen protection, mixture B is heated to 80-85°C and reacted for 2-3 hours.

[0068] After the reaction was completed, PLA was precipitated with ethanol and dried under vacuum for 24-48 hours to obtain modified PLA.

[0069] Step 6: Dissolve chitosan in deionized water at a concentration of 0.1-1% (40℃) to obtain a chitosan solution.

[0070] Step 7: Add the pulped wood pulp fiber, modified PAN nanofiber suspension, modified PTFE emulsion, modified PLA solution and chitosan solution to the mixing tank in sequence, and add sodium polyacrylate.

[0071] Use a mixer to stir at 500-600 rpm for 20-60 minutes to obtain mixed pulp.

[0072] Step 8: Pour the mixed pulp into the paper machine and form the paper, controlling the basis weight of the filter paper to be 40-60 g / m³. 2 .

[0073] Step 9: Lay the filter paper formed in Step 8 flat on a stainless steel plate and put it in an oven to dry (70-80℃, 30-60 minutes).

[0074] Step 10: Place the dried filter paper from Step 9 into a calender for calendering (95-105℃, 4-6MPa, 0.5-2 minutes) to obtain air filter material.

[0075] The present application will be further described below through specific embodiments.

[0076] Example 1

[0077] An air filter material comprising the following components:

[0078] Wood pulp fiber: 70kg (commercially available, NBKP, CanforPulp);

[0079] Modified PAN nanofibers: 10kg;

[0080] Modified PTFE emulsion: 1 kg;

[0081] Modified PLA: 10kg;

[0082] Chitosan: 0.3kg (commercially available, degree of deacetylation 90%);

[0083] Sodium polyacrylate (PAAS): 0.03kg (commercially available, CAS No. 9003-04-7).

[0084] This embodiment also provides a method for preparing an air filter material, including the following steps:

[0085] Step 1: Soak the wood pulp fibers in water for 24 hours, initially disperse them for 30 minutes (1000 rpm) using a high-speed disperser, and then beat them to 35°SR using a pulper.

[0086] Step 2: Prepare modified PAN nanofibers, including the following steps:

[0087] PAN nanofibers (commercially available, purchased from Suzhou Beike Nanotechnology Co., Ltd. in this example) were dispersed in DMF, and PEG monomethyl ether (commercially available, CAS No. 9004-74-4, preferred molecular weight 2000) was added to obtain mixture A.

[0088] The amount of DMF used is 5 times the weight of PAN nanofibers.

[0089] The amount of PEG monomethyl ether used is 10% of the weight of PAN nanofibers.

[0090] Under nitrogen protection, mixture A was heated to 60°C and reacted for 4 hours.

[0091] After the reaction was completed, the nanofibers were washed three times with ethanol and dried under vacuum for 24 hours to obtain the modified PAN nanofibers.

[0092] Step 3: Add the modified PAN nanofibers to deionized water and disperse them using an ultrasonic disruptor for 30 minutes (300W, intermittent ultrasonication) to prepare a modified PAN nanofiber suspension with a concentration of 0.1%.

[0093] Step 4: Prepare the modified PTFE emulsion, including the following steps:

[0094] The PTFE emulsion (commercially available, in this example purchased from Chemours 601X in the United States) was diluted with deionized water to a solid content of 5% to obtain a diluted PTFE emulsion.

[0095] Dodecyltrimethylammonium chloride was dissolved in deionized water to prepare a 0.1% dodecyltrimethylammonium chloride solution.

[0096] The amount of dodecyltrimethylammonium chloride used is 0.3% of the solid content of the PTFE emulsion.

[0097] The dodecyltrimethylammonium chloride solution was slowly added to the diluted PTFE emulsion and stirred for 30 minutes to fully disperse the dodecyltrimethylammonium chloride in the PTFE emulsion, thus obtaining the modified PTFE emulsion.

[0098] Step 5: Prepare modified PLA, including the following steps:

[0099] PLA (commercially available; in this example, the PLA resin type is 4032D, purchased from NatureWorks) was dissolved in dichloromethane to prepare a 10% PLA solution.

[0100] Hexamethylene diisocyanate and the catalyst dibutyltin dilaurate were added to the PLA solution to obtain mixture B.

[0101] The amount of HDI used is 1% of the weight of PLA, and the amount of DBTDL used is 0.01% of the weight of PLA.

[0102] Under nitrogen protection, mixture B was heated to 80°C and reacted for 2 hours.

[0103] After the reaction was completed, PLA was precipitated with ethanol and dried under vacuum for 24 hours to obtain modified PLA.

[0104] Step 6: Dissolve chitosan in deionized water to obtain a chitosan solution with a chitosan concentration of 0.1% (40℃).

[0105] Step 7: Add the pulped wood pulp fiber, modified PAN nanofiber suspension, modified PTFE emulsion, modified PLA solution and chitosan solution to the mixing tank in sequence, and add sodium polyacrylate.

[0106] Use a mixer to stir at 500 rpm for 30 minutes to obtain mixed pulp.

[0107] Step 8: Pour the mixed pulp into the paper machine, form the paper, and control the basis weight of the filter paper to 50 g / m³. 2 .

[0108] Step 9: Lay the filter paper formed in Step 8 flat on a stainless steel plate and put it in an oven to dry (80℃, 30 minutes).

[0109] Step 10: Place the dried filter paper from Step 9 into a calender for calendering (100℃, 5MPa, 1 minute) to obtain air filter material.

[0110] Performance testing:

[0111] 1. Filtration effect: Using outdoor particles as the pollution source, the wind speed was controlled at v = 1.1 m / s, and the experimental conditions were: T = 34~36℃, relative humidity 23%~29%, discharge voltage U1 = +9kV, polarization voltage U2 = +21kV. The filtration efficiency of the air filter material for 0.3μm particles was tested.

[0112] 2. Antibacterial effect: The antibacterial rate of air filter material against Escherichia coli was tested using the plate colony count method in accordance with GB / T 21510-2008 "Test Method for Antibacterial Performance of Nano-Inorganic Antibacterial Materials".

[0113] 3. Moisture resistance: Refer to GB / T 454-2020 "Determination of bursting strength of paper" to test the initial bursting strength of air filter materials.

[0114] The air filter material was then placed in an environment with 95% humidity for 48 hours, and its burst strength was tested again after the treatment.

[0115] The moisture resistance is calculated using the formula: Moisture resistance (%) = (Initial burst strength - Bursting strength after treatment) / Initial burst strength * 100%.

[0116] The lower the calculated moisture resistance, the less affected the air filter material is by moisture.

[0117] Test results:

[0118] 1. Filtration efficiency: 75.8%.

[0119] 2. Antibacterial rate: 95%.

[0120] 3. Moisture resistance: 3%.

[0121] Example 2

[0122] An air filter material comprising the following components:

[0123] Wood pulp fiber: 65kg (commercially available, NBKP, CanforPulp);

[0124] Modified PAN nanofibers: 15kg;

[0125] Modified PTFE emulsion: 1.5 kg;

[0126] Modified PLA: 8kg;

[0127] Chitosan: 0.5kg (commercially available, degree of deacetylation 90%);

[0128] Sodium polyacrylate (PAAS): 0.045 kg (commercially available, CAS No. 9003-04-7).

[0129] This embodiment also provides a method for preparing an air filter material, including the following steps:

[0130] Step 1: Soak the wood pulp fibers in water for 24 hours, initially disperse them for 30 minutes (1000 rpm) using a high-speed disperser, and then beat them to 40°SR using a pulper.

[0131] Step 2: Prepare modified PAN nanofibers, including the following steps:

[0132] PAN nanofibers (commercially available, purchased from Suzhou Beike Nanotechnology Co., Ltd. in this example) were dispersed in DMF, and PEG monomethyl ether (commercially available, CAS No. 9004-74-4, preferred molecular weight 2000) was added to obtain mixture A.

[0133] The amount of DMF used is four times the weight of PAN nanofibers.

[0134] The amount of PEG monomethyl ether used is 12% of the weight of PAN nanofibers.

[0135] Under nitrogen protection, mixture A was heated to 60°C and reacted for 4 hours.

[0136] After the reaction was completed, the nanofibers were washed three times with ethanol and dried under vacuum for 24 hours to obtain the modified PAN nanofibers.

[0137] Step 3: Add the modified PAN nanofibers to deionized water and disperse them using an ultrasonic disruptor for 30 minutes (300W, intermittent ultrasonication) to prepare a modified PAN nanofiber suspension with a concentration of 0.5%.

[0138] Step 4: Prepare the modified PTFE emulsion, including the following steps:

[0139] The PTFE emulsion (commercially available, in this example purchased from Chemours 601X in the United States) was diluted with deionized water to a solid content of 5% to obtain a diluted PTFE emulsion.

[0140] Dodecyltrimethylammonium chloride was dissolved in deionized water to prepare a 0.1% dodecyltrimethylammonium chloride solution.

[0141] The amount of dodecyltrimethylammonium chloride used is 0.5% of the solid content of the PTFE emulsion.

[0142] The dodecyltrimethylammonium chloride solution was slowly added to the diluted PTFE emulsion and stirred for 30 minutes to fully disperse the dodecyltrimethylammonium chloride in the PTFE emulsion, thus obtaining the modified PTFE emulsion.

[0143] Step 5: Prepare modified PLA, including the following steps:

[0144] PLA (commercially available; in this example, the PLA resin type is 4032D, purchased from NatureWorks) was dissolved in dichloromethane to prepare a 10% PLA solution.

[0145] Hexamethylene diisocyanate and the catalyst dibutyltin dilaurate were added to the PLA solution to obtain mixture B.

[0146] The amount of HDI used is 1.2% of the weight of PLA, and the amount of DBTDL used is 0.02% of the weight of PLA.

[0147] Under nitrogen protection, mixture B was heated to 80°C and reacted for 2 hours.

[0148] After the reaction was completed, PLA was precipitated with ethanol and dried under vacuum for 24 hours to obtain modified PLA.

[0149] Step 6: Dissolve chitosan in deionized water to obtain a chitosan solution with a chitosan concentration of 0.5% (40℃).

[0150] Step 7: Add the pulped wood pulp fiber, modified PAN nanofiber suspension, modified PTFE emulsion, modified PLA solution and chitosan solution to the mixing tank in sequence, and add sodium polyacrylate.

[0151] Use a mixer to stir at 500 rpm for 30 minutes to obtain mixed pulp.

[0152] Step 8: Pour the mixed pulp into the paper machine, form the paper, and control the basis weight of the filter paper to 50 g / m³. 2 .

[0153] Step 9: Lay the filter paper formed in Step 8 flat on a stainless steel plate and put it in an oven to dry (80℃, 30 minutes).

[0154] Step 10: Place the dried filter paper from Step 9 into a calender for calendering (100℃, 5MPa, 1 minute) to obtain air filter material.

[0155] Test results:

[0156] 1. Filtration efficiency: 76.2%.

[0157] 2. Antibacterial rate: 96%.

[0158] 3. Moisture resistance: 2.5%.

[0159] Comparative Example 1

[0160] An air filter material comprising the following components:

[0161] Wood pulp fiber: 70kg (commercially available, NBKP, CanforPulp);

[0162] PAN nanofibers: 10kg;

[0163] PTFE emulsion: 1 kg;

[0164] PLA: 10kg;

[0165] Chitosan: 0.3kg (commercially available, degree of deacetylation 90%);

[0166] Sodium polyacrylate (PAAS): 0.03kg (commercially available, CAS No. 9003-04-7).

[0167] This embodiment also provides a method for preparing an air filter material, including the following steps:

[0168] Step 1: Soak the wood pulp fibers in water for 24 hours, initially disperse them for 30 minutes (1000 rpm) using a high-speed disperser, and then beat them to 35°SR using a pulper.

[0169] Step 2: Add PAN nanofibers to deionized water and disperse them using an ultrasonic disruptor for 30 minutes (300W, intermittent ultrasonication) to prepare a PAN nanofiber suspension with a concentration of 0.1%.

[0170] Step 3: Dilute the PTFE emulsion (commercially available, in this example purchased from Chemours 601X in the United States) with deionized water to a solid content of 5% to obtain a diluted PTFE emulsion.

[0171] Step 4: Dissolve chitosan in deionized water to obtain a chitosan solution with a chitosan concentration of 0.1% (40℃).

[0172] Step 5: Add the pulped wood pulp fiber, PAN nanofiber suspension, PTFE diluted emulsion, PLA and chitosan solution to the mixing tank in sequence, and add sodium polyacrylate.

[0173] Use a mixer to stir at 500 rpm for 30 minutes to obtain mixed pulp.

[0174] Step 6: Pour the mixed pulp into the paper machine, form the paper, and control the basis weight of the filter paper to 50 g / m³. 2 .

[0175] Step 7: Lay the filter paper formed in Step 6 flat on a stainless steel plate and put it in an oven to dry (80℃, 30 minutes).

[0176] Step 8: Place the dried filter paper from Step 7 into a calender for calendering (100℃, 5MPa, 1 minute) to obtain air filter material.

[0177] Test results:

[0178] 1. Filtration efficiency: 51.5%.

[0179] 2. Antibacterial rate: 84%.

[0180] 3. Moisture resistance: 12%.

[0181] Comparative Example 1, based on Example 1, disrupted the special combination between wood pulp fibers, modified PAN nanofibers, modified PTFE emulsion, and modified PLA. According to the test results, the filtration efficiency and antibacterial rate of the air filter material in Comparative Example 1 were significantly lower than those in Examples 1-2, while its moisture resistance was much higher. This indicates that although the air filter material in Comparative Example 1 has a certain filtration and antibacterial effect, it is significantly inferior to that in Examples 1-2. Furthermore, after high humidity treatment, the air filter material in Comparative Example 1 was permeated by moisture, resulting in decreased strength and a significant reduction in burst resistance.

[0182] It should be understood that the application of this application is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of this application.

Claims

1. An air filter material, characterized in that, Includes the following components: Wood pulp fiber: 60-70 parts by weight; Modified PAN nanofibers: 10-20 parts by weight; Modified PTFE emulsion: 1-3 parts by weight; Modified PLA: 5-10 parts by weight; Chitosan: 0.1-1 parts by weight; Sodium polyacrylate: 0.01-0.1 parts by weight; The preparation of modified PAN nanofibers includes the following steps: PAN nanofibers, polar solvents, and PEG monomethyl ether are mixed and reacted at 55-65℃ for 4-6 hours under inert gas protection. Washing and drying yields modified PAN nanofibers; The preparation of modified PTFE emulsion includes the following steps: dodecyltrimethylammonium chloride is mixed and stirred with PTFE emulsion to obtain modified PTFE emulsion; The preparation of modified PLA includes the following steps: PLA, dichloromethane, isocyanate and catalyst are mixed and heated to 80-85℃ under inert gas protection for 2-3 hours; After precipitation and drying, modified PLA is obtained.

2. The air filter material according to claim 1, characterized in that, The amount of polar solvent used is 3-6 times the weight of PAN nanofibers; The amount of PEG monomethyl ether used is 8-12% of the weight of PAN nanofibers.

3. The air filter material according to claim 1, characterized in that, The amount of dodecyltrimethylammonium chloride used is 0.1-1% of the solid content of the PTFE emulsion.

4. The air filter material according to claim 1, characterized in that, The amount of isocyanate used is 0.5-2% of the weight of PLA, and the amount of catalyst used is 0.01-0.1% of the weight of PLA.

5. The air filter material according to claim 1, characterized in that, PLA is dissolved in dichloromethane to prepare a PLA solution with a concentration of 8-12%; then it is mixed with isocyanate and catalyst, and heated to 80-85℃ under inert gas protection for 2-3 hours.

6. A method for preparing an air filter material according to any one of claims 1-5, characterized in that, Includes the following steps: Wood pulp fibers are soaked in water and pulped to 35-40°SR; The pulped wood pulp fibers, modified PAN nanofibers, modified PTFE emulsion, modified PLA, chitosan, and sodium polyacrylate are mixed to obtain a mixed pulp. Papermaking is carried out using mixed pulp; after drying and calendering, air filter material is obtained.

7. The method for preparing the air filter material according to claim 6, characterized in that, Modified PAN nanofibers are mixed in the form of a modified PAN nanofiber suspension; the modified PAN nanofiber suspension includes modified PAN nanofibers and water; Chitosan participates in the mixing in the form of a chitosan solution; the chitosan solution includes chitosan and water.