Composite filter material and method for making same

Abstract

The application discloses a kind of composite filter material and preparation method thereof, it is related to filter material technical field.The application is when preparing composite filter material, modified carbon nanotube is prepared by hydroxylated carbon nanotube and antibacterial agent reaction;Short cut glass fiber is sequentially reacted with 3-aminopropyl triethoxysilane and phytic acid to prepare modified glass fiber;With modified glass fiber, micron glass wool fiber and submicron glass wool fiber as raw material, glass fiber filter paper is prepared using wet forming process;Modified carbon nanotube is prepared into carbon nanotube dispersion, sprayed on glass fiber filter paper, and composite filter material is prepared.The composite filter material prepared by the application has excellent antibacterial property and filtering performance.

Description

Technical Field

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

[0002] In modern society, people spend most of their time indoors, where air quality is often poor, and pollutants such as dust and particulate matter can harm human health. Currently, indoor air quality is primarily maintained through air purifiers and their high-efficiency filter materials. However, under certain temperature and humidity conditions, the dust filtration process of air purifiers can lead to bacterial growth and reproduction. Furthermore, the air also contains bioaerosols such as bacteria, viruses, and fungi. Especially with the recent outbreaks of influenza viruses, there is a widespread demand for antibacterial materials. Therefore, filter materials with high filtration efficiency and precision, as well as antibacterial and antiviral properties, are more in line with human health needs.

[0003] Currently, high-efficiency air filtration materials mainly include glass fiber filter paper (glass fiber filter paper for short) prepared by papermaking methods, meltblown nonwoven materials, and electrospun filter materials. Among them, glass fiber filter paper is widely used due to its simple preparation process, low production cost, high filtration efficiency, and numerous advantages such as corrosion resistance and heat resistance. However, ordinary glass fiber filter paper only has weak antibacterial ability, which cannot meet the application requirements. Therefore, it is essential to develop a glass fiber filter paper air filtration material with high antibacterial properties. Summary of the Invention

[0004] The purpose of this invention is to provide a composite filter material and its preparation method to solve the problems existing in the prior art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A composite filter material is prepared by using modified glass fiber, micron-sized glass wool fiber and submicron-sized glass wool fiber as raw materials and a wet molding process to prepare glass fiber filter paper; modified carbon nanotubes are formulated into a carbon nanotube dispersion and sprayed onto the glass fiber filter paper to obtain the composite filter material. The modified glass fiber is prepared by reacting chopped glass fibers sequentially with 3-aminopropyltriethoxysilane and phytic acid.

[0006] Furthermore, the modified carbon nanotubes are prepared by reacting hydroxylated carbon nanotubes with an antibacterial agent.

[0007] Furthermore, the antibacterial agent is prepared by reacting an antibacterial precursor with isophorone diisocyanate; The antibacterial precursor is prepared by reacting 3-bromo-1-propanol and triphenylphosphine.

[0008] Furthermore, the preparation method of the composite filter material includes the following preparation steps: (1) Dissolve 3-bromo-1-propanol and triphenylphosphine in N,N-dimethylformamide at a molar ratio of 1:1 to 10-12 times the mass of 3-bromo-1-propanol. React in an oil bath at 115-125°C for 60-70 h under nitrogen protection. Cool to room temperature, wash with ethyl acetate, and vacuum dry at 40-50°C for 10-14 h to obtain the antibacterial precursor. Mix the antibacterial precursor and tetrahydrofuran at a mass ratio of 1:(16-20), add an equimolar amount of isophorone diisocyanate of the antibacterial precursor, and add 0.0g of the antibacterial precursor by mass. An antibacterial agent was prepared by stirring dibutyltin dilaurate at 0.02 to 0.004 times its mass at 40 to 50 °C for 12 to 14 hours and then rotary evaporating under reduced pressure. The antibacterial agent, dibutyltin dilaurate, and N,N-dimethylformamide were mixed evenly at a mass ratio of 1:(0.001 to 0.003):(20 to 30). Hydroxylated carbon nanotubes at 0.5 to 0.6 times the mass of the antibacterial agent were added, and the mixture was stirred at 60 to 70 °C for 4 to 6 hours. The mixture was then filtered, washed with anhydrous ethanol, and vacuum dried at 60 to 70 °C for 20 to 24 hours to obtain modified carbon nanotubes. (2) Mix amino-functionalized glass fiber, phytic acid and 50wt% ethanol solution in a mass ratio of 1:(1~1.2):(30~40), stir and react at 60~70℃ for 10~12h, filter, wash with water, and vacuum dry at 50~60℃ to obtain modified glass fiber. (3) Weigh the modified glass fiber, micron-sized glass wool fiber, and submicron-sized glass wool fiber in a mass ratio of 3:3:4, with a total mass of 2.6 g. Disperse them in deionized water to a slurry concentration of 0.03 wt%. Adjust the pH of the dispersion to 2.5-3.5 with dilute sulfuric acid. Use a standard fiber desiccant at 10000 r·min -1 After dissolving for 8 minutes, a fiber dispersion was obtained; the fiber dispersion was injected into the forming wire of the paper machine, stirred, dehydrated and formed to obtain a wet filter paper blank; the wet filter paper blank was placed in a flat dryer and dried at 100~110 ℃ for 35~45 minutes to obtain glass fiber filter paper; (4) Mix modified carbon nanotubes, dispersant and distilled water in a mass ratio of 1:(0.4~0.6):600, and ultrasonically disperse for 10~20 min to prepare carbon nanotube dispersion; wet glass fiber filter paper for 5~7 min, spray the carbon nanotube dispersion onto the wetted glass fiber filter paper with a spray gun, and air dry naturally to obtain composite filter material.

[0009] Furthermore, the reaction principle of the antibacterial agent in step (1) is as follows: .

[0010] Furthermore, the preparation process of the hydroxylated carbon nanotubes in step (1) is as follows: potassium permanganate and distilled water are mixed evenly at a mass ratio of 1:(20~24) to obtain a potassium permanganate solution; carbon nanotubes and potassium permanganate solution are mixed at a mass ratio of 1:(50~60), refluxed at 100℃ for 10~12h, cooled to room temperature, filtered, and a mixed solvent with a volume ratio of V(HCl):V(H2O):V(H2O2)=1:2:2 is added to the filter cake. The mass of the mixed solvent is 20~30 times the mass of the carbon nanotubes. After no more bubbles are generated, the mixture is filtered, washed repeatedly with distilled water 5~7 times, and vacuum dried at 60~70℃ for 20~24h to obtain hydroxylated carbon nanotubes.

[0011] Furthermore, the carbon nanotubes are multi-arm carbon nanotubes with a diameter of 10~20 nm.

[0012] Furthermore, the preparation process of the amino-functionalized glass fiber in step (2) is as follows: chopped glass fiber and 50wt% ethanol solution are mixed at a mass ratio of 1:(80~100), 0.1~0.14 times the mass of chopped glass fiber of 3-aminopropyltriethoxysilane is added, the temperature is raised to 50~60℃ and stirred for 3~4h, filtered, washed with water, and dried under vacuum at 50~60℃ to obtain amino-functionalized glass fiber.

[0013] Furthermore, the average diameter of the chopped glass fibers is approximately 6 μm.

[0014] Furthermore, the average diameter of the micron-sized glass wool fibers in step (3) is 1.91 μm, and the average diameter of the submicron-sized glass wool fibers is 0.36 μm.

[0015] Furthermore, the dispersant in step (4) is sodium dodecylbenzenesulfonate.

[0016] Furthermore, the amount of carbon nanotube dispersion sprayed onto glass fiber filter paper in step (4) is 100 g / 20 cm. 2 .

[0017] Compared with the prior art, the beneficial effects achieved by the present invention are: An antibacterial precursor was prepared by reacting 3-bromo-1-propanol with triphenylphosphine; an antibacterial agent was prepared by reacting the antibacterial precursor with isophorone diisocyanate; modified carbon nanotubes were prepared by reacting the hydroxyl groups on hydroxylated carbon nanotubes with the isocyanate groups on the antibacterial agent. Numerous studies have shown that carbon nanotubes have antibacterial capabilities and possess excellent properties such as high mechanical strength and high temperature resistance. The antibacterial ability can be further enhanced by grafting cationic antibacterial agents onto carbon nanotubes. Then, the modified carbon nanotubes were loaded onto glass fiber filter paper using a spraying technique, which improved the antibacterial ability of the composite filter material.

[0018] Modified glass fibers were prepared by reacting short glass fibers sequentially with 3-aminopropyltriethoxysilane and phytic acid. A large amount of phytic acid with hydrophilic and antibacterial properties was attached to the surface of the short glass fibers, which further enhanced the antibacterial ability of the composite filter material. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] In the following specific embodiments, the hydroxylated carbon nanotubes are self-made, and the preparation process is as follows: Potassium permanganate and distilled water were mixed evenly at a mass ratio of 1:22 to obtain a potassium permanganate solution. Carbon nanotubes and potassium permanganate solution were mixed at a mass ratio of 1:50 and refluxed at 100℃ for 12 hours. After cooling to room temperature, the mixture was filtered. A mixed solvent with a volume ratio of V(HCl):V(H2O):V(H2O2) = 1:2:2 was added to the filter cake. The mass of the mixed solvent was 30 times the mass of the carbon nanotubes. After no more bubbles were generated, the mixture was filtered, washed repeatedly with distilled water 5 times, and dried under vacuum at 65℃ for 24 hours to obtain hydroxylated carbon nanotubes.

[0021] Example 1: A method for preparing a composite filter material, the method comprising the following preparation steps: (1) Dissolve 3-bromo-1-propanol and triphenylphosphine in N,N-dimethylformamide at a molar ratio of 1:1 to 10 times the mass of 3-bromo-1-propanol. React in an oil bath at 115°C for 70 h under nitrogen protection. Cool to room temperature, wash with ethyl acetate, and dry under vacuum at 40°C for 14 h to obtain the antibacterial precursor. Mix the antibacterial precursor and tetrahydrofuran at a mass ratio of 1:16, add an equimolar amount of isophorone diisocyanate to the mixture, and add... Dibutyltin dilaurate (0.002 times the mass of the antibacterial precursor) was added and stirred at 40°C for 14 hours. The mixture was then evaporated under reduced pressure to obtain an antibacterial agent. The antibacterial agent, dibutyltin dilaurate, and N,N-dimethylformamide were mixed evenly at a mass ratio of 1:0.001:20. Hydroxylated carbon nanotubes (0.5 times the mass of the antibacterial agent) were added, and the mixture was stirred at 60°C for 6 hours. The mixture was then filtered, washed with anhydrous ethanol, and vacuum dried at 60°C for 24 hours to obtain modified carbon nanotubes. (2) Short-cut glass fibers and 50wt% ethanol solution were mixed at a mass ratio of 1:80, and 0.1 times the mass of the short-cut glass fibers were added to 3-aminopropyltriethoxysilane. The mixture was heated to 50℃ and stirred for 4 hours. After filtration, washing with water, and vacuum drying at 50℃, amino-functionalized glass fibers were obtained. Amino-functionalized glass fibers, phytic acid, and 50wt% ethanol solution were mixed at a mass ratio of 1:1:30. The mixture was stirred at 60℃ for 12 hours, filtered, washed with water, and vacuum dried at 50℃ to obtain modified glass fibers. (3) Weigh the modified glass fiber, micron-sized glass wool fiber, and submicron-sized glass wool fiber in a mass ratio of 3:3:4, with a total mass of 2.6 g. Disperse them in deionized water to a slurry concentration of 0.03 wt%. Adjust the pH of the dispersion to 2.5 with dilute sulfuric acid and use a standard fiber disintegrator at 10000 r·min. -1 After dissolving for 8 minutes, a fiber dispersion was obtained; the fiber dispersion was injected into the forming wire of the paper machine, stirred, dehydrated and formed to obtain a wet filter paper blank; the wet filter paper blank was placed in a flat dryer and dried at 100 °C for 45 minutes to obtain glass fiber filter paper; (4) The modified carbon nanotubes, sodium dodecylbenzenesulfonate, and distilled water were mixed at a mass ratio of 1:0.4:600 and ultrasonically dispersed for 10 min to prepare a carbon nanotube dispersion. Glass fiber filter paper was moistened for 5 min, and the carbon nanotube dispersion was sprayed onto the moistened glass fiber filter paper using a spray gun at a spraying amount of 100 g / 20 cm. 2 The material is air-dried naturally to obtain a composite filter material.

[0022] Example 2: A method for preparing a composite filter material, the method comprising the following preparation steps: (1) Dissolve 3-bromo-1-propanol and triphenylphosphine in N,N-dimethylformamide at a molar ratio of 1:1 to 11 times the mass of 3-bromo-1-propanol. React in an oil bath at 120°C for 65 h under nitrogen protection. Cool to room temperature, wash with ethyl acetate, and dry under vacuum at 45°C for 12 h to obtain the antibacterial precursor. Mix the antibacterial precursor and tetrahydrofuran at a mass ratio of 1:18, add an equimolar amount of isophorone diisocyanate to the mixture, and add... Dibutyltin dilaurate, at a mass ratio of 0.003, was reacted with the antibacterial precursor at 45°C for 13 hours by stirring and then evaporated under reduced pressure to obtain an antibacterial agent. The antibacterial agent, dibutyltin dilaurate, and N,N-dimethylformamide were mixed evenly at a mass ratio of 1:0.002:25. Hydroxylated carbon nanotubes, at a mass ratio of 0.55, were added. The mixture was stirred at 65°C for 5 hours, filtered, washed with anhydrous ethanol, and vacuum dried at 65°C for 22 hours to obtain modified carbon nanotubes. (2) Short-cut glass fibers and 50wt% ethanol solution were mixed at a mass ratio of 1:90, and 0.12 times the mass of the short-cut glass fibers were added to 3-aminopropyltriethoxysilane. The mixture was heated to 55℃ and stirred for 3.5h. After filtration, washing with water, and vacuum drying at 55℃, amino-functionalized glass fibers were obtained. Amino-functionalized glass fibers, phytic acid, and 50wt% ethanol solution were mixed at a mass ratio of 1:1.1:35. The mixture was stirred for 11h at 65℃, filtered, washed with water, and vacuum dried at 55℃ to obtain modified glass fibers. (3) Weigh the modified glass fiber, micron-sized glass wool fiber, and submicron-sized glass wool fiber in a mass ratio of 3:3:4, with a total mass of 2.6 g. Disperse them in deionized water to a slurry concentration of 0.03 wt%. Adjust the pH of the dispersion to 3 with dilute sulfuric acid and use a standard fiber desiccant at 10000 r·min. -1 After dissolving for 8 minutes, a fiber dispersion was obtained; the fiber dispersion was injected into the forming wire of the paper machine, stirred, dehydrated and formed to obtain a wet filter paper blank; the wet filter paper blank was placed in a flat dryer and dried at 105 °C for 40 minutes to obtain glass fiber filter paper; (4) The modified carbon nanotubes, sodium dodecylbenzenesulfonate, and distilled water were mixed at a mass ratio of 1:0.5:600 and ultrasonically dispersed for 15 min to prepare a carbon nanotube dispersion. Glass fiber filter paper was moistened for 6 min, and the carbon nanotube dispersion was sprayed onto the moistened glass fiber filter paper using a spray gun at a spraying amount of 100 g / 20 cm. 2 The material is air-dried naturally to obtain a composite filter material.

[0023] Example 3: A method for preparing a composite filter material, the method comprising the following steps: (1) Dissolve 3-bromo-1-propanol and triphenylphosphine in N,N-dimethylformamide at a molar ratio of 1:1 to 12 times the mass of 3-bromo-1-propanol. React in an oil bath at 125°C for 60 h under nitrogen protection. Cool to room temperature, wash with ethyl acetate, and dry under vacuum at 50°C for 10 h to obtain the antibacterial precursor. Mix the antibacterial precursor and tetrahydrofuran at a mass ratio of 1:20, add an equimolar amount of isophorone diisocyanate to the mixture, and add... Dibutyltin dilaurate (0.004 times the mass of the antibacterial precursor) was added and reacted at 50°C for 12 hours with stirring. The mixture was then evaporated under reduced pressure to obtain an antibacterial agent. The antibacterial agent, dibutyltin dilaurate, and N,N-dimethylformamide were mixed evenly at a mass ratio of 1:0.003:30. Hydroxylated carbon nanotubes (0.6 times the mass of the antibacterial agent) were added, and the mixture was stirred at 70°C for 4 hours. The mixture was then filtered, washed with anhydrous ethanol, and vacuum dried at 70°C for 20 hours to obtain modified carbon nanotubes. (2) Short-cut glass fibers and 50wt% ethanol solution were mixed at a mass ratio of 1:100, and 0.14 times the mass of the short-cut glass fibers were added to 3-aminopropyltriethoxysilane. The mixture was heated to 60℃ and stirred for 3h. After filtration, the mixture was washed with water and dried under vacuum at 60℃ to obtain amino-functionalized glass fibers. Amino-functionalized glass fibers, phytic acid and 50wt% ethanol solution were mixed at a mass ratio of 1:1.2:40. The mixture was stirred for 10h at 70℃, filtered, washed with water and dried under vacuum at 60℃ to obtain modified glass fibers. (3) Weigh modified glass fiber, micron-sized glass wool fiber and submicron-sized glass wool fiber in a mass ratio of 3:3:4, with a total mass of 2.6 g, disperse them in deionized water, and the slurry concentration is 0.03 wt%; adjust the pH of the dispersion to 3.5 with dilute sulfuric acid, and dissolve it for 8 min at 10000 r·min-1 using a standard fiber dispersant to obtain a fiber dispersion; inject the fiber dispersion into the forming wire of the paper machine, stir, dehydrate and form to obtain a filter paper wet blank; place the filter paper wet blank in a flat dryer and dry it at 110 ℃ for 35 min to obtain glass fiber filter paper; (4) Modified carbon nanotubes, sodium dodecylbenzenesulfonate, and distilled water were mixed at a mass ratio of 1:0.6:600 and ultrasonically dispersed for 20 min to prepare a carbon nanotube dispersion. Glass fiber filter paper was moistened for 7 min, and the carbon nanotube dispersion was sprayed onto the moistened glass fiber filter paper using a spray gun at a spraying amount of 100 g / 20 cm. 2 The material is air-dried naturally to obtain a composite filter material.

[0024] Comparative Example 1: The difference between the preparation method of the composite filter material in Comparative Example 1 and Example 2 is that step (1) is omitted, and the "modified carbon nanotubes" in step (4) are replaced with "hydroxylated carbon nanotubes". The remaining steps are the same as in Example 2.

[0025] Comparative Example 2: The preparation method of the composite filter material in Comparative Example 2 differs from that in Example 2 in that step (2) is omitted, and the "modified glass fiber" in step (3) is replaced with "chopped glass fiber". The remaining steps are the same as in Example 2.

[0026] Comparative Example 3: The difference between the preparation method of the composite filter material in Comparative Example 3 and Example 2 is that steps (1) and (4) are omitted, and the "glass fiber filter paper" in step (3) is used as the "composite filter material". The remaining steps are the same as in Example 2.

[0027] Test case Antibacterial test: Escherichia coli and Staphylococcus aureus were used as test bacteria. The antibacterial rate of the samples was tested by shaking method according to GB / T 20944.3—2008. The test results are shown in Table 1.

[0028] Filtration performance testing: The filtration performance of the filter paper was measured using a TSI8130 automatic gas permeation test bench (USA). The generated sodium chloride aerosol particles exhibited a normal distribution with a median particle size of 0.26 μm. The test method conformed to standard EN143, and the test flow rate was 32 L·min. -1 The test results were taken as the average of the three groups of samples. The test results are shown in Table 2.

[0029] Table 1

[0030] Table 2

[0031] The experimental data in Tables 1 and 2 show that the composite filter material prepared in this application has excellent antibacterial ability and filtration efficiency.

[0032] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a composite filter material, characterized in that, The preparation method of the composite filter material includes the following preparation steps: (1) Dissolve 3-bromo-1-propanol and triphenylphosphine in N,N-dimethylformamide at a molar ratio of 1:1 to 10-12 times the mass of 3-bromo-1-propanol. React in an oil bath at 115-125°C for 60-70 h under nitrogen protection. Cool to room temperature, wash with ethyl acetate, and vacuum dry at 40-50°C for 10-14 h to obtain the antibacterial precursor. Mix the antibacterial precursor and tetrahydrofuran at a mass ratio of 1:(16-20), add an equimolar amount of isophorone diisocyanate of the antibacterial precursor, and add 0.0g of the antibacterial precursor by mass. An antibacterial agent was prepared by stirring dibutyltin dilaurate at 0.02 to 0.004 times its mass at 40 to 50 °C for 12 to 14 hours and then rotary evaporating under reduced pressure. The antibacterial agent, dibutyltin dilaurate, and N,N-dimethylformamide were mixed evenly at a mass ratio of 1:(0.001 to 0.003):(20 to 30). Hydroxylated carbon nanotubes at 0.5 to 0.6 times the mass of the antibacterial agent were added, and the mixture was stirred at 60 to 70 °C for 4 to 6 hours. The mixture was then filtered, washed with anhydrous ethanol, and vacuum dried at 60 to 70 °C for 20 to 24 hours to obtain modified carbon nanotubes. (2) Mix amino-functionalized glass fiber, phytic acid and 50wt% ethanol solution in a mass ratio of 1:(1~1.2):(30~40), stir and react at 60~70℃ for 10~12h, filter, wash with water, and vacuum dry at 50~60℃ to obtain modified glass fiber. (3) Weigh the modified glass fiber, micron-sized glass wool fiber, and submicron-sized glass wool fiber in a mass ratio of 3:3:4, with a total mass of 2.6 g. Disperse them in deionized water to a slurry concentration of 0.03 wt%. Adjust the pH of the dispersion to 2.5-3.5 with dilute sulfuric acid. Use a standard fiber desiccant at 10000 r·min -1 After dissolving for 8 minutes, a fiber dispersion was obtained; the fiber dispersion was injected into the forming wire of the paper machine, stirred, dehydrated and formed to obtain a wet filter paper blank; the wet filter paper blank was placed in a flat dryer and dried at 100~110 ℃ for 35~45 minutes to obtain glass fiber filter paper; (4) Mix modified carbon nanotubes, dispersant and distilled water in a mass ratio of 1:(0.4~0.6):600, and ultrasonically disperse for 10~20 min to prepare carbon nanotube dispersion; wet glass fiber filter paper for 5~7 min, spray the carbon nanotube dispersion onto the wetted glass fiber filter paper with a spray gun, and air dry naturally to obtain composite filter material.

2. The method for preparing a composite filter material according to claim 1, characterized in that, The reaction principle of the antibacterial agent in step (1) is as follows: 。 3. The method for preparing a composite filter material according to claim 1, characterized in that, The preparation process of the amino-functionalized glass fiber in step (2) is as follows: short glass fiber and 50wt% ethanol solution are mixed at a mass ratio of 1:(80~100), 0.1~0.14 times the mass of the short glass fiber is added to 3-aminopropyltriethoxysilane, the temperature is raised to 50~60℃ and stirred for 3~4h, filtered, washed with water, and dried under vacuum at 50~60℃ to obtain amino-functionalized glass fiber.

4. The method for preparing a composite filter material according to claim 3, characterized in that, The average diameter of the chopped glass fibers is 6 μm.

5. The method for preparing a composite filter material according to claim 1, characterized in that, The average diameter of the micron-sized glass wool fiber in step (3) is 1.91 μm, and the average diameter of the submicron-sized glass wool fiber is 0.36 μm.

6. The method for preparing a composite filter material according to claim 1, characterized in that, The dispersant in step (4) is sodium dodecylbenzenesulfonate.

7. A composite filter material, characterized in that, The composite filter material is prepared by the method for preparing composite filter material according to any one of claims 1 to 6.

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