Glass fiber composite filter material with adjustable aperture and preparation method thereof

Abstract

The invention provides an aperture-adjustable glass fiber composite filter material and a preparation method thereof, and the preparation method comprises the following steps: (1) mixing coarse glass fiber slurry and fine glass fiber slurry for papermaking to obtain a filter paper base material; (2) adding an aperture regulator into the high-molecular polymer solution, and uniformly mixing to obtain a composite polymer solution; wherein the aperture regulator is quaternary ammonium salt; and (3) immersing the filter paper base material in the composite polymer solution, drying and forming to obtain the aperture-adjustable glass fiber composite filter material. According to the scheme, the optimization of the mechanical strength, pore size distribution and antibacterial functionality of the composite filter material is synchronously realized on the basis of ensuring the filtering performance.

Description

Technical Field

[0001] This invention relates to the field of glass fiber filter material technology, and in particular to a glass fiber composite filter material with adjustable pore size and its preparation method. Background Technology

[0002] In numerous fields such as industrial filtration, air purification, and liquid separation, glass fiber filter paper has always played an indispensable role due to its excellent high-temperature resistance, chemical stability, and high filtration efficiency. However, due to the inherent structural characteristics of glass fiber, its mechanical strength is often insufficient to meet the stringent requirements of practical applications when used alone, making it prone to breakage and shedding, which seriously affects the filtration effect and service life. To address this challenge, related technologies commonly employ resin reinforcement of glass fiber filter paper. This involves coating or impregnating the glass fiber filter paper substrate with resin, which, after curing, forms a continuous film structure that binds the dispersed glass fibers together, thereby improving the overall mechanical properties of the filter paper. However, this method has significant drawbacks: the dense film formed during resin curing extensively clogs the original pores of the glass fiber filter paper, leading to decreased air permeability, a sharp increase in filtration resistance, and consequently, a deterioration of key filtration indicators, reducing actual efficiency and user experience. Furthermore, for special filtration scenarios with high porosity and hygiene requirements, this type of traditional resin-reinforced glass fiber filter paper is particularly unsuitable.

[0003] Therefore, there is an urgent need to provide a glass fiber composite filter material with adjustable pore size and its preparation method. Summary of the Invention

[0004] This invention provides a glass fiber composite filter material with adjustable pore size and its preparation method, which can solve the problem that existing glass fiber filter paper cannot simultaneously possess good filtration performance, mechanical properties and antibacterial properties.

[0005] In a first aspect, the present invention provides a method for preparing a glass fiber composite filter material with adjustable pore size, the method comprising the following steps: (1) The coarse glass fiber slurry and the fine glass fiber slurry are mixed and formed into filter paper substrate; (2) Add a pore size regulator to the polymer solution and mix well to obtain a composite polymer solution; wherein the pore size regulator is a quaternary ammonium salt; (3) The filter paper substrate is immersed in the composite polymer solution, dried and shaped to obtain the glass fiber composite filter material with adjustable pore size.

[0006] Preferably, in step (1), the diameter of the coarse glass fiber is 2~4μm and the length is 1~2mm; the diameter of the fine glass fiber is 0.5~2μm and the length is 0.5~1mm.

[0007] Preferably, the mass ratio of coarse glass fiber to fine glass fiber in the coarse glass fiber slurry and the fine glass fiber slurry is (1~6):(1~2).

[0008] Preferably, in step (1), the pulping concentration of the coarse glass fiber slurry and the fine glass fiber slurry is 1%~2%, and the pulping time is 15~20min.

[0009] Preferably, in step (2), the solute of the polymer solution is at least one of polyvinylidene fluoride, polylactic acid or polypropylene, and the solvent is dichloromethane.

[0010] More preferably, in step (2), the mass-volume concentration of the polymer solution is 0.5-2%.

[0011] Preferably, in step (2), the pore size regulator is hexadecyltrimethylammonium bromide or dodecyldimethylbenzylammonium chloride.

[0012] More preferably, in step (2), the mass-volume concentration of the pore size regulator in the composite polymer solution is 0.5% to 1%.

[0013] Preferably, in step (2), the mixing temperature is 30~35℃, the stirring speed is 300~500r / min, and the time is 30~40min.

[0014] More preferably, the immersion temperature is 25~30°C and the immersion time is 5~10 minutes.

[0015] Preferably, during the drying and molding process, the temperature is 45~50℃, the relative humidity is 55%~60%RH, and the static molding time is 10~15min.

[0016] Secondly, embodiments of the present invention also provide a glass fiber composite filter material with adjustable pore size, which is prepared by the preparation method described in any one of the first aspects above.

[0017] Compared with the prior art, the present invention has at least the following beneficial effects: In this invention, coarse and fine glass fiber slurries are first mixed and formed into a filter paper substrate with a specific pore size distribution. The substrate is then immersed in a composite solution containing a polymer and a quaternary ammonium salt pore size regulator. During subsequent molding, the endothermic effect caused by solvent evaporation in the polymer solution causes water vapor in the air to condense, forming uniformly distributed micro-droplets on the surface of the polymer solution. These micro-droplets act as pore templates, interacting with the continuously concentrated polymer phase. After the solvent and water have completely evaporated, a three-dimensional porous network structure and a uniform microporous structure are formed in the fiber pores and on the surface of the filter paper substrate, respectively. This enhances the mechanical strength of the substrate while preventing fiber pore blockage, further optimizing filtration efficiency. Simultaneously, the quaternary ammonium salt added to the polymer solution not only precipitates and dissolves in the condensed water droplets during solvent evaporation, increasing the droplet surface area and causing it to shrink, thus achieving precise control of the filter material pore size, but also imparts good antibacterial properties to the substrate. Ultimately, while ensuring filtration performance, the mechanical strength, pore size distribution, and antibacterial functionality of the filter material are simultaneously optimized. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a scanning electron microscope (SEM) image of the filter paper substrate with a pore size of 10-15 μm provided in Embodiment 2 of the present invention; Figure 2 This is a scanning electron microscope (SEM) image of a glass fiber composite filter material with adjustable pore size provided in Embodiment 2 of the present invention. Figure 3 This is a scanning electron microscope (SEM) image of a glass fiber composite filter material with adjustable pore size provided in Embodiment 12 of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] This invention provides a method for preparing a glass fiber composite filter material with adjustable pore size, the method comprising the following steps: (1) The coarse glass fiber slurry and the fine glass fiber slurry are mixed and formed into filter paper substrate; (2) Add a pore size regulator to the polymer solution and mix well to obtain a composite polymer solution; wherein the pore size regulator is a quaternary ammonium salt; (3) The filter paper substrate is immersed in the composite polymer solution, dried and shaped to obtain the glass fiber composite filter material with adjustable pore size.

[0022] In this embodiment of the invention, coarse and fine glass fiber slurries are first mixed and formed into a filter paper substrate with a specific pore size distribution. The substrate is then immersed in a composite solution containing a polymer and a quaternary ammonium salt pore size regulator. During subsequent molding, the endothermic effect caused by solvent evaporation in the composite polymer solution causes water vapor in the air to condense, forming uniformly distributed micro-droplets on the surface of the polymer solution. These micro-droplets act as pore templates, interacting with the continuously concentrated polymer phase. After the solvent and water have completely evaporated, a three-dimensional porous network structure and a uniform microporous structure are formed between the fiber pores and on the surface of the filter paper substrate, respectively. This enhances the mechanical strength of the substrate while preventing fiber pore blockage, further optimizing filtration efficiency. Simultaneously, the quaternary ammonium salt added to the composite polymer solution not only precipitates and dissolves in the condensed water droplets during solvent evaporation, increasing the droplet surface area and causing it to shrink, thus achieving precise control of the filter material pore size, but also imparts good antibacterial properties to the substrate. Ultimately, while ensuring filtration performance, the mechanical strength, pore size distribution, and antibacterial functionality of the filter material are simultaneously optimized.

[0023] According to some preferred embodiments, in step (1), the diameter of the coarse glass fiber is 2~4μm (e.g., it can be 2μm, 2.5μm, 3μm, 3.5μm or 4μm), and the length is 1~2mm (e.g., it can be 1mm, 1.5mm or 2mm); the diameter of the fine glass fiber is 0.5~2μm (e.g., it can be 0.5μm, 1μm, 1.5μm or 2μm), and the length is 0.5~1mm (e.g., it can be 1mm, 1.5mm or 2mm). (The thickness is 0.5mm, 0.8mm, or 1mm); the mass ratio of coarse glass fiber to fine glass fiber in the coarse glass fiber slurry and the fine glass fiber slurry is (1~6):(1~2) (for example, it can be 1:1, 1:1.5, 1:2, 2:1, 2:1.5, 2:2, 3:1, 3:1.5, 3:2, 4:1, 4:1.5, 4:2, 5:1, 5:1.5, 5:2, 6:1, 6:1.5, or 6:2).

[0024] According to some preferred embodiments, in step (1), the pulping concentration of the coarse glass fiber slurry and the fine glass fiber slurry is 1% to 2% (for example, it can be 1%, 1.5% or 2%), and the pulping time is 15 to 20 minutes (for example, it can be 15 minutes, 18 minutes or 20 minutes).

[0025] In this embodiment of the invention, coarse glass fibers with a larger diameter and longer length are first selected as the skeleton material, while fine glass fibers with a smaller diameter and shorter length are embedded in the gaps between the coarse glass fibers in the skeleton, thus finely controlling the pore structure. The coarse and fine glass fibers are then mixed with water and pulped to obtain coarse glass fiber slurry and fine glass fiber slurry, respectively. By adjusting the ratio of coarse and fine glass fiber slurry, the pore size of the glass fiber filter paper substrate can be initially controlled. A higher proportion of coarse glass fiber results in a larger pore size and better air permeability in the formed substrate. Increasing the proportion of fine glass fiber effectively fills the gaps between the fiber networks, reducing the average pore size and improving filtration accuracy. Subsequently, the coarse and fine glass fiber slurries are mixed in a certain ratio and then paper-made to obtain a glass fiber filter paper substrate with a specific pore size. Therefore, in this embodiment of the invention, the ratio of coarse and fine glass fiber slurry can be adjusted according to the pore size of the target substrate.

[0026] According to some preferred embodiments, in step (2), the solute of the polymer solution is at least one of polyvinylidene fluoride, polylactic acid or polypropylene, and the solvent is dichloromethane; the mass-volume concentration of the polymer solution is 0.5~2% (for example, it can be 0.5%, 1%, 1.5% or 2%).

[0027] In this embodiment of the invention, the aforementioned types of polymers are selected as reinforcing phases. These polymers are added to a solvent and stirred and mixed under constant temperature water bath conditions of 30-35°C to obtain a polymer solution of a certain mass-volume concentration. All of these polymers possess excellent film-forming ability, forming a tough solid film after solvent evaporation. This allows for the construction of a robust three-dimensional porous network between glass fibers, significantly improving the mechanical strength of the substrate. Furthermore, the solvent used rapidly absorbs heat during evaporation, inducing water vapor in the air to condense into uniform micro-droplets that remain on the surface of the formed polymer film, providing a physical template for the formation of a regular microporous structure. Thus, the rapid concentration of the polymer solution and the volatile properties of the solvent work synergistically to form a three-dimensional porous network structure and a uniform microporous structure between the fiber pores and on the surface of the filter paper substrate, respectively. This enhances the mechanical strength of the substrate while preventing fiber pore blockage, further optimizing filtration efficiency and filtration resistance.

[0028] Meanwhile, experiments conducted in this invention have confirmed that a suitable concentration of polymer solution is beneficial for enhancing the mechanical strength of the substrate while ensuring good filtration efficiency and reducing filtration resistance. If the concentration of the polymer solution is too low, it is not conducive to ensuring good mechanical strength of the substrate. On the other hand, if the concentration of the polymer solution is too high, although it can significantly enhance the mechanical properties of the filter material, the excessively high concentration will cause the polymer to overfill the fiber pores, reduce the effective interconnected channels, and thus increase the filtration resistance.

[0029] According to some preferred embodiments, in step (2), the pore size regulator is hexadecyltrimethylammonium bromide or dodecyldimethylbenzylammonium chloride; in the composite polymer solution, the mass-volume concentration of the pore size regulator is 0.5%~1% (for example, it can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%).

[0030] In this embodiment of the invention, adding the aforementioned quaternary ammonium salts to the polymer solution enables effective regulation of the microporous structure of the substrate and antibacterial functionalization. When solvent evaporation induces water vapor to condense into microdroplets, quaternary ammonium salt molecules in the solution precipitate and accumulate at the water droplet interface. By changing the interface, the water droplets shrink, thereby forming micropores with smaller diameters in the polymer membrane. By systematically adjusting the concentration of quaternary ammonium salts in the solution, precise control of the final pore size can be achieved. Experiments of this invention have confirmed that the higher the concentration of the pore size regulator, the smaller the volume of the formed water droplets and the smaller the resulting micropore size. Although this can improve filtration efficiency, it will increase filtration resistance. Conversely, the lower the concentration of the pore size regulator, the larger the formed pore size. Although this is beneficial for reducing flow resistance, the density of antibacterial functional groups per unit area decreases significantly, making it difficult to meet the functional requirements of the filter material for inhibiting microbial growth in humid environments or during long-term use. Therefore, in this embodiment of the invention, by rationally controlling the concentration of the quaternary ammonium salt pore size regulator, the synergistic regulation of pore size control and antibacterial performance is achieved, thereby preparing a composite filter material with good filtration performance, permeability and biological stability.

[0031] According to some preferred embodiments, in step (2), the mixing temperature is 30~35℃ (for example, it can be 30℃, 32℃ or 35℃), the stirring speed is 300~500r / min (for example, it can be 300r / min, 400r / min or 500r / min), and the time is 30~40min (for example, it can be 30min, 35min or 40min).

[0032] According to some preferred embodiments, the immersion temperature is 25~30°C (e.g., 25°C, 28°C or 30°C), and the time is 5~10 min (e.g., 5 min, 8 min or 10 min).

[0033] According to some preferred embodiments, during the drying and molding process, the temperature is 45~50℃ (e.g., 45℃, 48℃ or 60℃), the relative humidity is 55%~60%RH (e.g., 55%RH, 58%RH or 60%RH), and the static molding time is 10~15min (e.g., 10min, 11min, 12min, 13min, 14min or 15min).

[0034] In this embodiment of the invention, the filter paper substrate prepared above is completely immersed in the prepared composite polymer solution at room temperature to ensure that the substrate fully adsorbs the solution. The immersed substrate is then removed and sent to the molding zone, where the temperature and humidity are precisely controlled. This balances the filtration efficiency, flow resistance, and mechanical properties of the filter material while simultaneously regulating the pore size distribution. Maintaining a constant high humidity environment during molding ensures that sufficient water vapor condenses evenly across the entire surface and interior of the filter material during solvent evaporation and heat absorption, forming micro-droplets that serve as microporous templates. If the humidity is too low, a sufficient number and size of micro-droplets cannot be formed, resulting in uneven micropore size or distribution. Simultaneously, using a suitable drying temperature is beneficial for forming a fine and regular microporous structure. If the drying temperature is too high, the violent evaporation of the solvent will cause uneven cooling in certain areas, resulting in uneven droplet size distribution and ultimately a disordered microporous structure.

[0035] This invention also provides a glass fiber composite filter material with adjustable pore size obtained by any of the above-described preparation methods.

[0036] In this embodiment of the invention, by using the above preparation method, while utilizing polymer to enhance the mechanical properties of glass fiber filter material, the filter material's filtration and permeability can be ensured by controlling the micropore size, and its antibacterial properties can be imparted, thereby giving the filter material excellent broad-spectrum performance, which can simultaneously meet differentiated filtration precision requirements and strict hygiene and safety standards. To more clearly illustrate the technical solution and advantages of the present invention, the following describes in detail, through several embodiments, an adjustable pore size glass fiber composite filter material and its preparation method.

[0037] Example 1: (1) Coarse glass fibers (diameter 2~4μm, length 1~2mm) and fine glass fibers (diameter 0.5~2μm, length 0.5~1mm) are added to water and pulped to obtain coarse glass fiber pulp and fine glass fiber pulp with a pulping concentration of 1%; Coarse glass fiber slurry and fine glass fiber slurry are mixed at a fiber mass ratio of 6:1, and after papermaking, filter paper substrate with a pore size of 15~20μm is obtained. (2) Add the polymer (polyvinylidene fluoride) to the solvent (dichloromethane solvent), and stir at a stirring speed of 500 r / min for 30 min under a constant temperature water bath at 30℃ until the polymer is completely dissolved to obtain a polymer solution with a mass volume concentration of 1% (w / v); then, add the pore size regulator (hexadecyltrimethylammonium bromide) to the polymer solution, and continue stirring at 30℃ for 20 min to ensure complete dissolution to obtain a composite polymer solution; wherein, the mass volume concentration of the pore size regulator in the composite polymer solution is 0.5% (w / v). (3) Immerse the filter paper substrate completely in the composite polymer solution for 5 minutes to ensure that the substrate fully absorbs the solution. Then take out the immersed substrate and send it to the molding area. Control the environmental parameters of the molding area: temperature 45℃, relative humidity 55% RH, and let it stand for 10 minutes to obtain glass fiber composite filter material with adjustable pore size.

[0038] Example 2: (1) Coarse glass fibers (diameter 2~4μm, length 1~2mm) and fine glass fibers (diameter 0.5~2μm, length 0.5~1mm) are added to water and pulped to obtain coarse glass fiber pulp and fine glass fiber pulp with a pulping concentration of 1%; Coarse glass fiber slurry and fine glass fiber slurry are mixed at a fiber mass ratio of 3:2, and after papermaking, filter paper substrate with a pore size of 10~15μm is obtained. (2) Add the polymer (polyvinylidene fluoride) to the solvent (dichloromethane solvent), and stir at a stirring speed of 500 r / min for 30 min under a constant temperature water bath at 30℃ until the polymer is completely dissolved to obtain a polymer solution with a mass volume concentration of 1% (w / v); then, add the pore size regulator (hexadecyltrimethylammonium bromide) to the polymer solution, and continue stirring at 30℃ for 20 min to ensure complete dissolution to obtain a composite polymer solution; wherein, the mass volume concentration of the pore size regulator in the composite polymer solution is 0.5% (w / v). (3) Immerse the filter paper substrate completely in the composite polymer solution for 5 minutes to ensure that the substrate fully absorbs the solution. Then take out the immersed substrate and send it to the molding area. Control the environmental parameters of the molding area: temperature 45℃, relative humidity 55% RH, and let it stand for 10 minutes to obtain glass fiber composite filter material with adjustable pore size.

[0039] Example 3: (1) Coarse glass fibers (diameter 2~4μm, length 1~2mm) and fine glass fibers (diameter 0.5~2μm, length 0.5~1mm) are added to water and pulped to obtain coarse glass fiber pulp and fine glass fiber pulp with a pulping concentration of 1%; Coarse glass fiber slurry and fine glass fiber slurry are mixed at a fiber mass ratio of 2:3, and after papermaking, filter paper substrate with a pore size of 5~10μm is obtained. (2) Add the polymer (polyvinylidene fluoride) to the solvent (dichloromethane solvent), and stir at a stirring speed of 500 r / min for 30 min under a constant temperature water bath at 30℃ until the polymer is completely dissolved to obtain a polymer solution with a mass volume concentration of 1% (w / v); then, add the pore size regulator (hexadecyltrimethylammonium bromide) to the polymer solution, and continue stirring at 30℃ for 20 min to ensure complete dissolution to obtain a composite polymer solution; wherein, the mass volume concentration of the pore size regulator in the composite polymer solution is 0.5% (w / v). (3) Immerse the filter paper substrate completely in the composite polymer solution for 5 minutes to ensure that the substrate fully absorbs the solution. Then take out the immersed substrate and send it to the molding area. Control the environmental parameters of the molding area: temperature 45℃, relative humidity 55% RH, and let it stand for 10 minutes to obtain glass fiber composite filter material with adjustable pore size.

[0040] Example 4: Example 4 is basically the same as Example 2, except that in step (2), the mass volume concentration of the pore size regulator in the composite polymer solution is 0.8% (w / v).

[0041] Example 5: Example 5 is basically the same as Example 2, except that in step (2), the mass volume concentration of the pore size regulator in the composite polymer solution is 1.0% (w / v).

[0042] Example 6: Example 6 is basically the same as Example 2, except that in step (2), the pore size regulator in the composite polymer solution is dodecyl dimethyl benzyl ammonium chloride.

[0043] Example 7: Example 7 is basically the same as Example 2, except that in step (2), the mass volume concentration of the polymer solution is 0.5% (w / v).

[0044] Example 8: Example 8 is basically the same as Example 2, except that in step (2), the mass volume concentration of the polymer solution is 1.5% (w / v).

[0045] Example 9: Example 9 is basically the same as Example 2, except that in step (2), the mass volume concentration of the polymer solution is 2.0% (w / v).

[0046] Example 10: Example 10 is basically the same as Example 2, except that in step (2), the polymer in the polymer solution is polylactic acid.

[0047] Example 11: Example 11 is basically the same as Example 2, except that in step (2), the polymer in the polymer solution is polypropylene.

[0048] Example 12: Example 12 is basically the same as Example 2, except that in step (2), the mass volume concentration of the polymer solution is 3.0% (w / v).

[0049] Example 13: Example 13 is basically the same as Example 2, except that in step (2), the mass volume concentration of the pore size regulator in the composite polymer solution is 2.0% (w / v).

[0050] Example 14: Example 14 is basically the same as Example 2, except that in step (3), the temperature is 60°C, the relative humidity is 50%RH, and the static molding time is 10min.

[0051] Example 15: Example 15 is basically the same as Example 2, except that in step (3), the temperature is 40°C, the relative humidity is 65%RH, and the static molding time is 10 min.

[0052] Comparative Example 1: Comparative Example 1 is basically the same as Example 2, except that in step (2), the pore size regulator (hexadecyltrimethylammonium bromide) is added to the solvent (dichloromethane solvent), and stirred at a stirring speed of 500r / min for 30min under a constant temperature water bath at 30℃ until it is completely dissolved, and a solution with a mass volume concentration of 0.5% (w / v) is obtained.

[0053] Comparative Example 2: Comparative Example 2 is basically the same as Example 2, except that in step (2), the polymer (polyvinylidene fluoride) is added to the solvent (dichloromethane solvent), and stirred at a stirring speed of 500r / min for 30min under a constant temperature water bath at 30℃ until the polymer is completely dissolved, and a polymer solution with a mass volume concentration of 1% (w / v) is obtained.

[0054] Comparative Example 3: (1) Coarse glass fibers (diameter 2~4μm, length 1~2mm) and fine glass fibers (diameter 0.5~2μm, length 0.5~1mm) are added to water and pulped to obtain coarse glass fiber pulp and fine glass fiber pulp with a pulping concentration of 1%; Coarse glass fiber slurry and fine glass fiber slurry are mixed at a fiber mass ratio of 6:1, and after papermaking, filter paper substrate with a pore size of 15~20μm is obtained. (2) Polypropylene emulsion was applied to the surface of the filter paper substrate and then dried at 150°C for 5 minutes to obtain glass fiber composite filter material.

[0055] The performance of the glass fiber composite filter media samples with adjustable pore size provided in the examples and comparative examples was tested, and the test results are shown in Table 1 below: Longitudinal tensile strength test: Refer to GB / T 12914-2018 "Determination of tensile strength of paper and paperboard"; Filtration efficiency test: Refer to GB / T 40353-2021 "Air Filter Paper"; Resistance test: Refer to GB / T 40353-2021 "Air Filter Paper"; Average pore size test: Refer to ASTM D6767-21; The quality factor is calculated using the following formula: In the formula, P is the penetration rate, which is dimensionless, E is the filtration efficiency, and R is the filtration resistance, in Pa.

[0056] Table 1 Combined with Table 1 and Figures 1 to 2 As can be seen from the present invention, the glass fiber composite filter material prepared in the embodiments of the present invention has both good mechanical properties and filtration performance and low filtration resistance. Furthermore, the pore size of the composite filter material can be adjusted by regulating the concentration of the composite polymer solution and the content of the pore size regulator, such as... Figure 3As shown, if the concentration of the polymer solution in Example 12 is too high, the fiber pores of the composite filter material will be overfilled, thereby reducing the pore size of the filter material and increasing the filtration resistance.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a glass fiber composite filter material with adjustable pore size, characterized in that, The preparation method includes the following steps: (1) The coarse glass fiber slurry and the fine glass fiber slurry are mixed and formed into filter paper substrate; (2) Add a pore size regulator to the polymer solution and mix well to obtain a composite polymer solution; wherein the pore size regulator is a quaternary ammonium salt; (3) The filter paper substrate is immersed in the composite polymer solution, dried and shaped to obtain the glass fiber composite filter material with adjustable pore size.

2. The preparation method according to claim 1, characterized in that, In step (1), the coarse glass fiber has a diameter of 2~4μm and a length of 1~2mm; the fine glass fiber has a diameter of 0.5~2μm and a length of 0.5~1mm; and / or In the coarse glass fiber slurry and the fine glass fiber slurry, the mass ratio of coarse glass fiber to fine glass fiber is (1~6):(1~2).

3. The preparation method according to claim 1, characterized in that, In step (1), the pulping concentration of the coarse glass fiber slurry and the fine glass fiber slurry is 1%~2%, and the pulping time is 15~20min.

4. The preparation method according to claim 1, characterized in that, In step (2), the solute of the polymer solution is at least one of polyvinylidene fluoride, polylactic acid, or polypropylene, and the solvent is dichloromethane; and / or The mass-volume concentration of the polymer solution is 0.5-2%.

5. The preparation method according to claim 1, characterized in that, In step (2), the pore size regulator is hexadecyltrimethylammonium bromide or dodecyldimethylbenzylammonium chloride.

6. The preparation method according to claim 1, characterized in that, In step (2), the mass-volume concentration of the pore size regulator in the composite polymer solution is 0.5%~1%.

7. The preparation method according to claim 1, characterized in that, In step (2), the mixing temperature is 30~35℃, the stirring speed is 300~500r / min, and the time is 30~40min.

8. The preparation method according to claim 1, characterized in that, The immersion temperature is 25~30℃, and the time is 5~10 minutes.

9. The preparation method according to claim 1, characterized in that, During the drying and molding process, the temperature is 45~50℃, the relative humidity is 55%~60%RH, and the static molding time is 10~15min.

10. A glass fiber composite filter material with adjustable pore size, characterized in that, It is prepared by any one of claims 1 to 9.

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