Antistatic filter cloth and preparation method thereof

Abstract

The invention discloses an antistatic filter cloth and a preparation method thereof, and relates to the technical field of filter materials. The technical key points are measured by weight and are composed of the following components: 35-55 parts of modified antistatic fiber, 25-35 parts of polyester fiber, 4-7 parts of anti-ultraviolet agent, and 3-5 parts of cross-linking agent. The technical effect is that the safety hazards caused by static electricity are effectively avoided through low surface resistance, the adsorption of dust and impurities is reduced, and stable operation is ensured in various environments. The tensile strength is significantly enhanced, making the filter cloth more tough and durable, extending the service life, and reducing the replacement frequency and maintenance cost. In terms of filtration efficiency, the high efficiency performance of up to 98%-99% can accurately and stably remove tiny particles and meet the needs of high-precision filtration. In particular, it still has excellent antibacterial and antiviral properties without adding any antibacterial and antiviral materials.

Description

Technical Field

[0001] The invention relates to the technical field of filter materials, in particular to an antistatic filter cloth and a preparation method thereof. Background Art

[0002] Filter cloth is widely used in many industrial production processes and some places with high environmental requirements, such as electronic manufacturing workshops, medical and health fields, etc. However, there are many problems with traditional filter cloth. First, ordinary filter cloth is very easy to generate static electricity during the friction process. Static electricity not only causes dust to be adsorbed on the surface of the filter cloth, reducing the filtration efficiency, but also may cause static electricity sparks, which poses a great safety hazard in some flammable and explosive environments. Second, in the fields of medical and health, filter cloth needs to have good antibacterial and antiviral capabilities to prevent the spread of bacteria and viruses, but the performance of traditional filter cloth in this regard is often insufficient.

[0003] At present, although there are some antistatic filter cloths on the market, their antistatic performance is limited, and few of them can simultaneously take into account good antibacterial and antiviral properties. Existing improvement methods are mostly to simply add antistatic agents or antibacterial agents, which cannot fundamentally solve the problem of synergistic improvement of material performance and cannot meet the growing and diversified needs. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides an antistatic filter cloth and a preparation method thereof, which can significantly improve the antistatic performance of the filter cloth.

[0005] To achieve the above purpose, the present invention provides the following technical solution: an antistatic filter cloth and a preparation method thereof, which are composed of the following components by weight: 35-55 parts of modified antistatic fiber, 25-35 parts of polyester fiber, 4-7 parts of anti-ultraviolet agent, and 3-5 parts of cross-linking agent.

[0006] Preferably, the modified antistatic fiber is prepared from the following components by weight: 45-55 parts of polyethylene terephthalate, 8-12 parts of surface acidified carbon nanotubes, 10-13 parts of quaternary ammonium salt antistatic agent, and 3-4 parts of coupling agent.

[0007] Preferably, the anti-ultraviolet agent is a mixture of benzophenone and benzotriazole in a ratio of 1:1-2.

[0008] Preferably, the cross-linking agent is a mixture of glutaraldehyde and epoxy resin in a ratio of 2:1-3.

[0009] Preferably, the method comprises the following steps:

[0010] S1, performing surface acidification treatment on the carbon nanotubes, soaking them in a mixed solution of nitric acid and sulfuric acid for 2-3 hours, then repeatedly rinsing them with deionized water until they are neutral, and then drying them; at the same time, vacuum drying the polyethylene terephthalate at 80-100° C. for 6-8 hours, controlling the moisture content to be below 0.05%;

[0011] S2, adding the treated polyethylene terephthalate, carbon nanotubes, quaternary ammonium salt antistatic agent and coupling agent into a twin-screw extruder, the screw speed is 300-400r / min, the temperature of each zone is: 230-240°C for feeding section, 250-260°C for melting section, 260-270°C for mixing section, 270-280°C for homogenizing section, nitrogen protection is introduced during the melt blending process, the nitrogen flow rate is controlled at 0.5-1L / min, and then high-speed spinning is performed through a spinning machine, the spinning speed is 3000-4000m / min, and the spinning temperature is accurately controlled at 280-300°C according to the formula to obtain modified antistatic fiber;

[0012] S3, adding modified antistatic fiber, polyester fiber, anti-ultraviolet agent, and cross-linking agent into a planetary mixer, with an orbital speed of 100-150 r / min, a rotation speed of 200-300 r / min, and a stirring time of 30-40 minutes, and adding 0.1%-0.3% of the total weight of the material. The organic silicon dispersing aid is stirred evenly to obtain a mixed material;

[0013] S4. The mixed material is formed by a needle punching method or a hydroentanglement method. The needle punching method uses a variable needle plate with a starting needle distance of 5 mm and gradually reduced to 2 mm, and the needle depth is controlled at 10-15 mm. The hydroentanglement method uses a multi-stage hydroentanglement process, with an initial hydroentanglement pressure of 10-15 MPa, which is gradually increased to 20-30 MPa. A narrow slit nozzle is used, and the distance between the nozzle and the filter cloth is 10-15 cm to obtain an antistatic filter cloth.

[0014] S5. Heat-set the antistatic filter cloth by infrared heating at a temperature of 190-210°C for 1.5-2.5 minutes, while applying a tension of 5-10N; then put it into an aqueous solution containing an appropriate amount of detergent, and use ultrasonic assisted water washing at an ultrasonic frequency of 20-40kHz for 20-30 minutes, and finally use hot air circulation drying at a drying temperature of 80-100°C for 30-40 minutes to obtain the final antistatic filter cloth.

[0015] Preferably, in the process of preparing the modified antistatic fiber, the screw diameter of the twin-screw extruder is 40-60 mm.

[0016] Preferably, during the needle punching process, the needle punching frequency of the needle punching machine is 800-1200 times / min.

[0017] Preferably, during the hydroentanglement forming process, the water tank temperature of the hydroentanglement equipment is controlled at 20-30°C.

[0018] Preferably, after heat setting and before washing, the filter cloth is pre-stretched with a stretching ratio of 1.1-1.3.

[0019] Compared with the prior art, the present invention provides an antistatic filter cloth and a preparation method thereof, which have the following beneficial effects: low surface resistance effectively avoids the safety hazards caused by static electricity, reduces the adsorption of dust and impurities, and ensures stable operation in various environments. The tensile strength is significantly enhanced, making the filter cloth more tough and durable, extending the service life, and reducing the replacement frequency and maintenance costs. In terms of filtration efficiency, the high efficiency performance of up to 98%-99% can accurately and stably remove tiny particles and meet the needs of high-precision filtration. In particular, without adding any antibacterial and antiviral materials, it still has excellent antibacterial and antiviral properties. In addition, after being processed through carefully designed multi-process processes, the filter cloth has excellent dimensional stability. When used under different environmental conditions, it can always maintain a stable shape, ensuring the consistency and reliability of the filtration effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The figure is a bar chart comparing the antibacterial rate and antiviral rate of the embodiments of the present invention and the comparative examples. DETAILED DESCRIPTION

[0021] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0022] Surface resistance test, test standard: Test according to ASTMD257-14 "DC resistance or conductivity test method for insulating materials".

[0023] Test steps:

[0024] Prepare the test samples and cut the antistatic filter cloth into three square samples with a size of 100 mm × 100 mm.

[0025] Using a high resistance meter, place the sample between the test electrodes, ensuring that the electrodes are in full contact with the sample.

[0026] Under the environmental conditions of 23℃±2℃ and relative humidity of 50%±5%, apply a test voltage of 100V to the sample, read and record the stabilized resistance value.

[0027] The three samples were tested separately and the average value was taken as the surface resistance value of the antistatic filter cloth of this group.

[0028] Tensile strength test, test standard: refer to GB / T3923.1-2013 "Tensile properties of textile fabrics Part 1: Determination of breaking strength and elongation at break (strip method)".

[0029] Test steps:

[0030] The antistatic filter cloth was cut into 5 rectangular samples with a length of 250 mm and a width of 50 mm.

[0031] Adjust the parameters of the electronic universal material testing machine and set the tensile speed to 100 mm / min.

[0032] Clamp the specimen in the upper and lower clamps of the testing machine, ensuring that the specimen is in a vertical position in the clamps and that the clamps have uniform clamping force on the specimen.

[0033] Start the testing machine and stretch the sample until it breaks, and record the maximum force value at the time of fracture.

[0034] The five samples were tested separately, and the average value was calculated and taken as the tensile strength value of the antistatic filter cloth of this group.

[0035] Filtration efficiency test, test standard: Test in accordance with GB / T6165-2008 "High Efficiency Air Filter Performance Test Method Efficiency and Resistance".

[0036] Test steps:

[0037] To prepare the filter material sample for testing, the antistatic filter cloth is sealed and mounted on a circular test frame to form a sample with an effective filtration area of ​​100 cm².

[0038] Build a filtration efficiency test system, which includes an aerosol generator, an aerosol photometer, a test air duct and other equipment.

[0039] Sodium chloride aerosol was used as the test aerosol, and the occurrence concentration was (20-30) mg / m³.

[0040] Install the test sample in the test air duct and adjust the air flow speed so that the surface wind speed through the sample reaches 0.5m / s.

[0041] The aerosol concentrations at the upstream and downstream of the test air duct were measured respectively, and the filtration efficiency was calculated according to the formula. Each sample was tested 3 times, and the average value was taken as the filtration efficiency value of the antistatic filter cloth of this group.

[0042] Antibacterial rate test, test standard: Test according to GB / T20944.3-2008 "Evaluation of antibacterial properties of textiles Part 3: Oscillation method".

[0043] Test steps:

[0044] Prepare bacterial suspensions of Staphylococcus aureus (ATCC6538) and Escherichia coli (ATCC8739) at a concentration of (1-5) × 10 6 CFU / mL.

[0045] The antistatic filter cloth was cut into 5 samples of 25 mm × 25 mm in size and placed in a sterile conical flask.

[0046] Add 10 mL of nutrient broth containing bacterial suspension into each conical flask so that the sample is completely immersed in the bacterial solution.

[0047] The conical flask was placed in a shaking incubator and cultured at 37°C and 120 r / min for 24 hours.

[0048] After the culture was completed, 1 mL of the shaking solution was taken for serial dilution, and then the dilutions were spread on nutrient agar plates, cultured in an incubator at 37°C for 24 hours, and the number of colonies on the plates was counted.

[0049] At the same time, a blank control (bacterial suspension without the sample) was set up and the same steps were followed. The antibacterial rate was calculated according to the formula, and Staphylococcus aureus and Escherichia coli were tested respectively, and the average value was taken as the antibacterial rate value of the antistatic filter cloth for the corresponding bacteria.

[0050] Antiviral rate test, test standard: refer to YY / T1465.3-2016 "Medical Device Immunogenicity Evaluation Method Part 3: Plaque Formation Test" for testing.

[0051] Test steps:

[0052] Select influenza virus (such as H1N1) as the test virus and dilute the virus solution to an appropriate concentration.

[0053] The antistatic filter cloth was cut into three samples of 20 mm × 20 mm in size and placed in a sterile culture dish.

[0054] Add 1 mL of virus solution to each culture dish to allow the sample to fully adsorb the virus.

[0055] After 30 minutes, the sample was taken out and placed in a culture bottle containing cell culture medium and co-cultured with monkey kidney cells (Vero cells).

[0056] The culture flasks were incubated in a 37°C, 5% CO2 incubator for 72 hours.

[0057] After the culture was completed, the cytopathic effect was observed and the virus titer in the culture flask was determined by plaque counting method.

[0058] At the same time, a positive control (containing virus liquid but no sample) and a negative control (no virus liquid and sample) were set up. The antiviral rate was calculated according to the formula, and the three samples were tested separately, and the average value was taken as the antiviral rate value of the antistatic filter cloth of this group.

[0059] Dimensional stability test, test standard: Test in accordance with the relevant provisions of GB / T8629-2017 "Household Washing and Drying Procedure for Textile Testing".

[0060] Test steps:

[0061] Cut the antistatic filter cloth into three square samples of 200mm×200mm in size, mark two mutually perpendicular center lines on the samples, measure the distance from the intersection of the two center lines to each side, and record the initial size.

[0062] The samples were washed and dried for 5 times according to the standard washing procedure, with the washing temperature at 40°C, standard detergent, and low-temperature drying (temperature not exceeding 60°C).

[0063] After completing the washing and drying cycle, place the sample in an environmental condition of 23℃±2℃ and 50%±5% relative humidity for 24 hours to allow it to reach equilibrium.

[0064] Measure the distance from the marked point to each side again and calculate the dimensional change rate. Test the three samples separately and take the average value as the dimensional stability (dimensional change rate after heat setting) value of the group of antistatic filter cloth.

[0065] Example 1

[0066] An antistatic filter cloth and a preparation method thereof, specifically comprising the following steps:

[0067] S1. 10 parts of carbon nanotubes were subjected to surface acidification treatment, immersed in a mixed solution of nitric acid and sulfuric acid (volume ratio of 1:3) for 2 hours, then repeatedly rinsed with deionized water until neutral, and dried in a vacuum drying oven at 80°C for 12 hours; 50 parts of polyethylene terephthalate were vacuum dried at 80°C for 8 hours, and the moisture content was controlled below 0.05%.

[0068] S2, adding the treated polyethylene terephthalate, carbon nanotubes, 12 parts of quaternary ammonium salt antistatic agent, and 3 parts of coupling agent into a twin-screw extruder, the screw speed is 300r / min, and the temperature of each zone is: 230°C for the feeding section, 250°C for the melting section, 260°C for the mixing section, and 270°C for the homogenizing section. During the melt blending process, nitrogen protection is introduced, and the nitrogen flow rate is controlled at 0.5L / min, and then high-speed spinning is performed through a spinning machine, the spinning speed is 3000m / min, and the spinning temperature is 280°C to obtain a modified antistatic fiber.

[0069] S3, mixing: add 40 parts of modified antistatic fiber, 30 parts of polyester fiber, 5 parts of anti-ultraviolet agent which is a mixture of benzophenone and benzotriazole in a ratio of 1:1, and 4 parts of cross-linking agent which is a mixture of glutaraldehyde and epoxy resin in a ratio of 2:1 into a planetary mixer, with an orbital speed of 100 r / min, a rotation speed of 200 r / min, and a stirring time of 30 minutes. At the same time, add 0.1% of the total weight of the material into a silicone dispersing aid, and stir evenly to obtain a mixed material.

[0070] S4. Forming: The mixed material is formed by a needle punching method, using a variable needle pitch needle plate, with an initial needle pitch of 5 mm and gradually reduced to 2 mm, a needle punching depth controlled at 10 mm, and a needle punching frequency of 800 times / min to obtain an antistatic filter cloth.

[0071] S5, post-treatment: The antistatic filter cloth is heat-set by infrared heating at a temperature of 190°C for 2.5 minutes, and a tension of 5N is applied at the same time; then, it is placed in an aqueous solution containing an appropriate amount of detergent, and ultrasonic-assisted washing is performed at a frequency of 20kHz for 20 minutes, and finally, hot air circulation drying is performed at a drying temperature of 80°C for 40 minutes to obtain the final antistatic filter cloth.

[0072] Example 2

[0073] An antistatic filter cloth and a preparation method thereof, specifically comprising the following steps:

[0074] S1. 12 parts of carbon nanotubes were subjected to surface acidification treatment, immersed in a mixed solution of nitric acid and sulfuric acid (volume ratio of 1:3) for 2.5 hours, then repeatedly rinsed with deionized water until neutral, and dried in a vacuum drying oven at 80°C for 12 hours; 45 parts of polyethylene terephthalate were vacuum dried at 90°C for 7 hours, and the moisture content was controlled below 0.05%.

[0075] S2, adding the treated polyethylene terephthalate, carbon nanotubes, 13 parts of quaternary ammonium salt antistatic agent, and 4 parts of coupling agent into a twin-screw extruder, the screw speed is 350r / min, and the temperature of each zone is: 235°C for the feeding section, 255°C for the melting section, 265°C for the mixing section, and 275°C for the homogenizing section. During the melt blending process, nitrogen protection is introduced, and the nitrogen flow rate is controlled at 0.8L / min, and then high-speed spinning is performed through a spinning machine, the spinning speed is 3500m / min, and the spinning temperature is 290°C to obtain a modified antistatic fiber.

[0076] S3, mixing: 50 parts of modified antistatic fiber, 25 parts of polyester fiber, 6 parts of anti-ultraviolet agent mixed with benzophenone and benzotriazole in a ratio of 1:1.5, and 3 parts of cross-linking agent mixed with glutaraldehyde and epoxy resin in a ratio of 2:2 are added into a planetary mixer with an orbital speed of 120 r / min and a rotation speed of 250 r / min for 35 minutes. At the same time, 0.2% of the total weight of the material is added with an organosilicon dispersing aid, and the mixture is uniformly stirred to obtain a mixed material.

[0077] S4. Molding: The mixed material is molded by hydroentanglement, using a multi-stage hydroentanglement process, with an initial hydroentanglement pressure of 12 MPa, which is gradually increased to 25 MPa. A narrow slit nozzle is used, and the distance between the nozzle and the filter cloth is 12 cm. The water tank temperature of the hydroentanglement equipment is controlled at 25°C to obtain an antistatic filter cloth.

[0078] S5, post-treatment: The antistatic filter cloth is heat-set by infrared heating at a temperature of 200°C for 2 minutes, and a tension of 8N is applied at the same time; then, it is placed in an aqueous solution containing an appropriate amount of detergent, and ultrasonic-assisted washing is performed at a frequency of 30kHz for 25 minutes, and finally, hot air circulation drying is performed at a drying temperature of 90°C for 35 minutes to obtain the final antistatic filter cloth.

[0079] Example 3

[0080] An antistatic filter cloth and a preparation method thereof, specifically comprising the following steps:

[0081] S1. 8 parts of carbon nanotubes were subjected to surface acidification treatment, immersed in a mixed solution of nitric acid and sulfuric acid (volume ratio of 1:3) for 3 hours, then repeatedly rinsed with deionized water until neutral, and dried in a vacuum drying oven at 80°C for 12 hours; 55 parts of polyethylene terephthalate were vacuum dried at 100°C for 6 hours, and the moisture content was controlled below 0.05%.

[0082] S2, adding the treated polyethylene terephthalate, carbon nanotubes, 10 parts of quaternary ammonium salt antistatic agent, and 3 parts of coupling agent into a twin-screw extruder, the screw speed is 400r / min, and the temperature of each zone is: 240°C for the feeding section, 260°C for the melting section, 270°C for the mixing section, and 280°C for the homogenizing section. During the melt blending process, nitrogen protection is introduced, and the nitrogen flow rate is controlled at 1L / min, and then high-speed spinning is performed through a spinning machine, the spinning speed is 4000m / min, and the spinning temperature is 300°C to obtain a modified antistatic fiber.

[0083] S3, mixing: 45 parts of modified antistatic fiber, 30 parts of polyester fiber, 7 parts of anti-ultraviolet agent mixed with benzophenone and benzotriazole in a ratio of 1:2, and 5 parts of cross-linking agent mixed with glutaraldehyde and epoxy resin in a ratio of 2:3 are added into a planetary mixer with an orbital speed of 150 r / min and a rotation speed of 300 r / min for 40 minutes. At the same time, 0.3% of the total weight of the materials is added with an organosilicon dispersing aid, and the mixture is stirred evenly to obtain a mixed material.

[0084] S4. Forming: The mixed material is formed by a needle punching method, using a variable needle pitch needle plate, with an initial needle pitch of 5 mm and gradually reduced to 2 mm, a needle punching depth controlled at 15 mm, and a needle punching frequency of 1200 times / min to obtain an antistatic filter cloth.

[0085] S5, post-treatment: the antistatic filter cloth blank is heat-set by infrared heating at a temperature of 210°C for 1.5 minutes, and a tension of 10N is applied at the same time; then it is placed in an aqueous solution containing an appropriate amount of detergent, and ultrasonic-assisted washing is performed at a frequency of 40kHz for 30 minutes, and finally hot air circulation drying is performed at a drying temperature of 100°C for 30 minutes to obtain the final antistatic filter cloth.

[0086] Comparative Example 1:

[0087] S1. Without performing surface acidification treatment on carbon nanotubes, 8 parts of carbon nanotubes, 55 parts of polyethylene terephthalate (without strict moisture control, moisture content of about 0.2%), 10 parts of quaternary ammonium salt antistatic agent, and 3 parts of coupling agent are directly added into a common reactor, melt blended and reacted at 250-280°C for 3 hours (without nitrogen protection), and then spun through a common spinning machine at a spinning speed of 2000m / min and a spinning temperature of 270°C (without precise control), to obtain modified antistatic fibers.

[0088] S2. Mixing: 45 parts of modified antistatic fiber, 30 parts of polyester fiber, 7 parts of anti-ultraviolet agent (mixed in an unspecified proportion), and 5 parts of cross-linking agent (mixed in an unspecified proportion) were uniformly stirred using a common mixer at a stirring speed of 100 r / min for 20 minutes without adding a dispersing aid.

[0089] S3. Forming: A needle punching method is adopted, using a needle plate with a fixed needle distance of 5 mm, a needle punching depth of 8 mm, and a needle punching frequency of 600 times / min to obtain an antistatic filter cloth.

[0090] S4. Post-treatment: Heat setting is performed by ordinary electric heating at a temperature of 170°C for 1 minute without tension. Washing is performed by ordinary immersion washing for 15 minutes, and drying is performed by natural air drying.

[0091] Comparative Example 2:

[0092] S1. The carbon nanotubes are subjected to simple physical cleaning instead of acid treatment, and 8 parts of the treated carbon nanotubes, 55 parts of polyethylene terephthalate (dried in an ordinary oven with a moisture content of about 0.1%), 10 parts of quaternary ammonium salt antistatic agent, and 3 parts of coupling agent are added into a twin-screw extruder, but the screw speed is set to 200r / min, and the temperature of each zone is 10°C lower than that in the invention. The mixture is melt-blended without nitrogen protection, and then the spinning speed is 2500m / min and the spinning temperature is 280°C to obtain a modified antistatic fiber.

[0093] S2. Mixing: Use an ordinary mixer to evenly mix 45 parts of modified antistatic fiber, 30 parts of polyester fiber, 7 parts of anti-ultraviolet agent (mixed in an unspecified proportion), and 5 parts of cross-linking agent (mixed in an unspecified proportion) at a stirring speed of 150 r / min for 25 minutes, and add 0.05% of a dispersing aid (lower than the amount used in the invention).

[0094] S3. Forming: A needle punching method is adopted, using a needle plate with a fixed needle distance of 4 mm, a needle punching depth of 12 mm, and a needle punching frequency of 700 times / min to obtain an antistatic filter cloth.

[0095] S4, post-treatment: heat setting is performed by ordinary electric heating, the temperature is 180℃, the time is 1.5 minutes, and a tension of 3N is applied. Washing is performed by ordinary immersion washing, the washing time is 20 minutes, and drying is performed by ordinary oven drying, the temperature is 70℃, and the drying time is 25 minutes.

[0096] Comparative Example 3:

[0097] S1. The carbon nanotubes are acidified, but the soaking time is only 1 hour. 8 parts of the treated carbon nanotubes, 55 parts of polyethylene terephthalate (dried in a vacuum drying oven at 70°C and with a moisture content of about 0.08%), 10 parts of a quaternary ammonium salt antistatic agent, and 3 parts of a coupling agent are added into a twin-screw extruder. The screw speed is 350 r / min. The temperature of each zone is the same as that of the invention, but melt blending is performed at a nitrogen flow rate of 0.3 L / min (lower than the amount used in the invention). Then, the spinning speed is 3500 m / min and the spinning temperature is 290°C to obtain a modified antistatic fiber.

[0098] S2. Mixing: Use a planetary mixer, but the revolution speed is 80r / min, the rotation speed is 150r / min, the stirring time is 35 minutes, add 0.2% of the dispersing agent, and stir 45 parts of modified antistatic fiber, 30 parts of polyester fiber, 7 parts of anti-ultraviolet agent (mixed in an unspecified proportion), and 5 parts of cross-linking agent (mixed in an unspecified proportion) evenly.

[0099] S3. Forming: The hydroentanglement method is adopted, the hydroentanglement pressure is always maintained at 15 MPa, and a common nozzle is used. The distance between the nozzle and the filter cloth is 8 cm to obtain the antistatic filter cloth.

[0100] S4, post-treatment: infrared heating is used for heat setting, the temperature is 200℃, the time is 2 minutes, and the tension is 7N. Ultrasonic assisted water washing is used for water washing, but the frequency is 15kHz, the water washing time is 25 minutes, and hot air circulation drying is used for drying, the temperature is 90℃, and the drying time is 35 minutes.

[0101] Comparative Example 4:

[0102] S1. Fiber selection: Use the common antistatic fiber on the market with polyacrylonitrile as the base material and adding conventional antistatic agents (such as potassium alkyl phosphate).

[0103] S2, mixing: 45 parts of the commercial antistatic fiber, 30 parts of polyester fiber, 7 parts of anti-ultraviolet agent (mixed in an unspecified proportion), and 5 parts of cross-linking agent (mixed in an unspecified proportion) were added into a common mixer at a stirring speed of 120 r / min for 30 minutes without adding a dispersing agent.

[0104] S3. Forming: A needle punching method is adopted, using a needle plate with a fixed needle distance of 4 mm, a needle punching depth of 10 mm, and a needle punching frequency of 750 times / min to obtain an antistatic filter cloth.

[0105] S4, post-treatment: heat setting is performed by ordinary electric heating, the temperature is 185℃, the time is 1.5 minutes, and a tension of 4N is applied. Washing is performed by ordinary immersion washing, the washing time is 20 minutes, and drying is performed by ordinary oven drying, the temperature is 75℃, and the drying time is 30 minutes.

[0106] The antistatic filter cloths obtained in Examples 1, 2, 3 and Comparative Examples 1, 2, 3, and 4 were respectively cut into three square specimens with a size of 100 mm × 100 mm, and the test items were numbered 2024-JDLB-1, 2024-JDLB-2, 2024-JDLB-3, 2024-JDLB-4, 2024-JDLB-5, 2024-JDLB-6 and 2024-JDLB-7, and the test samples were subjected to surface resistance test, tensile strength test and filtration efficiency test. The specific test results are shown in Table 1.

[0107] Table 1

[0108]

[0109] The test samples were tested for antibacterial rate, antiviral rate and dimensional stability. The specific test results are shown in Table 2.

[0110] Table 2

[0111]

[0112] From the test data, the antistatic filter cloth of the embodiment of the present invention shows obvious advantages in various performances compared with the comparative example, which is due to the improvement of a series of process steps.

[0113] In terms of antistatic performance, the surface resistance of the embodiment is significantly lower than that of the comparative example. This is mainly due to the surface acidification treatment of the carbon nanotubes, which increases the active sites of the carbon nanotubes, so that when melt-blended with raw materials such as polyethylene terephthalate, it can more effectively form a conductive network. At the same time, the use of a twin-screw extruder and precise temperature and speed control ensure that the raw materials are evenly dispersed and the conductive performance is enhanced. In the comparative examples, for example, the carbon nanotubes are not acidified in comparative example 1, and a common reactor is used, resulting in uneven mixing of the raw materials, poor formation of the conductive network, and a significant increase in surface resistance.

[0114] In terms of tensile strength, the Example has higher strength. This is because during the preparation process, high-speed spinning technology makes the fiber molecules more regular in orientation and enhances the bonding force between fibers. Parameter optimization in the needle punching and spunlace forming processes, such as the variable needle spacing design of the needle punching method, the appropriate needle punching depth and frequency, and the multi-stage pressure control of the spunlace method, all help to improve the overall strength of the filter cloth. Comparative Example 2 has a low screw speed and unreasonable forming process parameters, resulting in loose bonding between fibers and reduced tensile strength.

[0115] In terms of filtration efficiency, the embodiment is as high as 98%-99%, which is much higher than the comparative example. This is due to the optimization of the filter cloth structure in the molding process, such as the needle punching and water entanglement to make the fibers entangled more tightly and evenly, forming a more reasonable filtration pore size distribution. At the same time, the addition of modified antistatic fibers may also improve the interaction between the filter cloth and the filter. In comparative example 3, due to the single water entanglement pressure and the improper distance between the nozzle and the filter cloth, the filter cloth structure is not ideal and the filtration efficiency is limited.

[0116] In terms of antibacterial and antiviral properties, the antibacterial and antiviral rates of the examples are significantly higher than those of the comparative examples without adding antibacterial and antiviral materials. This is probably due to the unique structure and composition of the modified antistatic fiber, which changes the interaction mode with bacteria and viruses at the microscopic level. For example, the synergistic effect of carbon nanotubes and quaternary ammonium salt antistatic agents may destroy the structure of bacteria and viruses or inhibit their activity. Comparative Example 4 uses ordinary antistatic fibers on the market, which do not have the unique structure of the fiber of the present invention, and has poor antibacterial and antiviral properties.

[0117] In terms of dimensional stability, the dimensional change rate of the embodiment after heat setting is low. This is due to the precise temperature control of the infrared heating method and the appropriate tension applied during the heat setting process, which ensures the structural stability of the filter cloth at high temperatures. At the same time, the optimized washing and drying processes, such as ultrasonic-assisted washing and hot air circulation drying, reduce the dimensional changes caused by the washing and drying processes. Comparative Example 1 uses ordinary electric heating, the temperature control is inaccurate, and there is no tension applied. The washing and drying methods are improper, resulting in a high dimensional change rate.

[0118] In summary, the present invention achieves significant improvements in antistatic performance, tensile strength, filtration efficiency, antibacterial and antiviral properties, and dimensional stability of the antistatic filter cloth by improving a series of process steps such as raw material processing, fiber preparation, mixing, molding, and post-processing. It has outstanding substantive characteristics and significant progress.

[0119] The above are only specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent replacements or modifications made based on the present invention to solve basically the same technical problems and achieve basically the same technical effects are all included in the protection scope of the present invention.

Claims

1. A method for preparing an antistatic filter cloth, characterized in that: The following steps are involved: S1, performing surface acidification treatment on the carbon nanotubes, soaking them in a mixed solution of nitric acid and sulfuric acid for 2-3 hours, then repeatedly rinsing them with deionized water until they are neutral, and then drying them; at the same time, vacuum drying the polyethylene terephthalate at 80-100° C. for 6-8 hours, controlling the moisture content to be below 0.05%; S2, adding the treated polyethylene terephthalate, carbon nanotubes, quaternary ammonium salt antistatic agent and coupling agent into a twin-screw extruder, the screw speed is 300-400r / min, the temperature of each zone is: 230-240℃ for feeding section, 250-260℃ for melting section, 260-270℃ for mixing section, 270-280℃ for homogenizing section, nitrogen protection is introduced during the melt blending process, the nitrogen flow rate is controlled at 0.5-1L / min, and then high-speed spinning is carried out through a spinning machine, the spinning speed is 3000-4000m / min, and the spinning temperature is accurately controlled at 280-300℃ according to the formula to obtain a new antistatic fiber; S3, adding the new antistatic fiber, polyester fiber, anti-ultraviolet agent, and cross-linking agent into a planetary mixer, with a revolution speed of 100-150 r / min, a rotation speed of 200-300 r / min, and a stirring time of 30-40 minutes, and adding 0.1%-0.3% of the total weight of the material, and stirring to obtain a mixed material; S4. The mixed material is formed by a needle punching method or a hydroentanglement method. The needle punching method uses a variable needle plate with a starting needle distance of 5 mm and gradually reduced to 2 mm, and the needle depth is controlled at 10-15 mm. The hydroentanglement method uses a multi-stage hydroentanglement process, with an initial hydroentanglement pressure of 10-15 MPa, which is gradually increased to 20-30 MPa. A narrow slit nozzle is used, and the distance between the nozzle and the filter cloth is 10-15 cm to obtain an antistatic filter cloth. S5, heat-setting the antistatic filter cloth by infrared heating at a temperature of 190-210° C. for 1.5-2.5 minutes, while applying a tension of 5-10N; then putting it into an aqueous solution containing an appropriate amount of detergent, washing it with ultrasonic assistance, the ultrasonic frequency is 20-40kHz, the washing time is 20-30 minutes, and finally drying it with hot air circulation, the drying temperature is controlled at 80-100° C., and the drying time is 30-40 minutes, to obtain the final antistatic filter cloth; The anti-ultraviolet agent is a mixture of benzophenone and benzotriazole in a ratio of 1:1-2; The cross-linking agent is prepared by mixing glutaraldehyde and epoxy resin in a ratio of 2:1-3.

2. The preparation method according to claim 1, characterized in that: In the preparation process of the novel antistatic fiber, the screw diameter of the twin-screw extruder is 40-60 mm.

3. The preparation method according to claim 1, characterized in that: During the needle punching process, the needle punching frequency of the needle punching machine is 800-1200 times / min.

4. The preparation method according to claim 1, characterized in that: During hydroentanglement, the water tank temperature of the hydroentanglement equipment is controlled at 20-30℃.

5. The preparation method according to claim 1, characterized in that: After heat setting and before washing, the filter cloth is pre-stretched with a stretching ratio of 1.1-1.

3.

6. An antistatic filter cloth, characterized in that: The method according to claim 1 is used to prepare the composition, and the composition comprises the following components in parts by weight: 35-55 parts of new antistatic fiber, 25-35 parts of polyester fiber, 4-7 parts of anti-ultraviolet agent, and 3-5 parts of cross-linking agent.

7. The antistatic filter cloth according to claim 6, characterized in that: The novel antistatic fiber is prepared from the following components by weight: 45-55 parts of polyethylene terephthalate, 8-12 parts of carbon nanotubes subjected to surface acidification treatment, 10-13 parts of quaternary ammonium salt antistatic agent, and 3-4 parts of coupling agent.

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