A fluorine-free high-flux anti-adhesion fiber membrane filter material and a preparation method thereof

Abstract

This invention discloses a fluorine-free, high-flux, anti-adhesion fiber membrane filter material and its preparation method, belonging to the technical field of high-temperature flue gas filter materials. The filter material consists of a polyphenylene sulfide (PPS) needle-punched felt substrate layer, a PPS melt-blown membrane layer, and a sepiolite-PDMS composite anti-adhesion coating loaded on the membrane surface. The anti-adhesion coating is composed of hydrophobically modified sepiolite fibers coated with polydimethylsiloxane, forming a three-dimensional permeable network structure with properties such as being fluorine-free, superhydrophobic, high-temperature resistant, and anti-adhesive. The filter material prepared by this invention exhibits excellent anti-clogging properties, low resistance, high filtration efficiency, and long service life under high-temperature, high-humidity flue gas environments containing viscous substances such as ammonium bisulfate. It solves the technical problems of traditional coated filter media being prone to adhesion, difficult to clean, and short-life. Furthermore, its fluorine-free nature enables environmentally friendly closed-loop systems, meeting the requirements of sustainable development.

Description

Technical Field

[0001] This invention relates to the field of high-temperature flue gas filtration materials, specifically to a fluorine-free high-flux anti-adhesion fiber membrane filtration material and its preparation method. Background Technology

[0002] Baghouse dust collectors are widely used for high-temperature flue gas purification in industries such as steel, cement, and power. In complex flue gas environments containing ammonium bisulfate (ABS), moisture, and fine particulate matter, traditional membrane filter media are prone to particle adhesion and caking, leading to increased filtration resistance, difficulty in dust removal, and a significantly shortened service life. Currently, most membrane filter media on the market focus on improving filtration accuracy, but their surface anti-adhesion properties are insufficient. Especially under high temperature and humidity conditions, condensate and ABS condensate easily wet the membrane surface, exacerbating clogging and significantly reducing the service life of the filter media.

[0003] To address the aforementioned issues, current technologies improve the anti-adhesion properties of filter media to water and ammonium bisulfate by impregnating with fluorinated emulsions or loading with hydrophobic coatings. For example, Chinese patent CN119455528A discloses a technique of adding bentonite to a PTFE composite emulsion and then treating the filter media by impregnation, thereby improving the anti-adhesion and durability of the filter media. Chinese patent CN114875659A prepares Ti / Si core-shell structured microparticles from nano-titanium dioxide and nano-silica, formulates an impregnation solution, and loads it onto surface-treated filter media through a padding-baking process to obtain superhydrophobic filter media. However, while the fluorinated materials in the above solutions can effectively improve hydrophobicity, their environmental persistence and bioaccumulation risks are increasingly concerning; and rigid particles such as nano-titanium dioxide and silica are prone to agglomeration and clogging on the surface of the coated filter media fiber membrane, seriously affecting the air permeability of the filter media, making it difficult to simultaneously achieve anti-adhesion function and high throughput characteristics.

[0004] Therefore, developing a composite filter material that combines high throughput, strong anti-adhesion, high temperature resistance, and long service life is of great significance for improving the operating efficiency and reliability of bag filters under complex flue gas conditions. Summary of the Invention

[0005] To address the problem of traditional coated filter media easily clogging in high-temperature, high-humidity flue gas containing sticky substances, resulting in high filter resistance and short lifespan, this invention aims to provide a fluorine-free, high-flux, anti-adhesion fiber membrane filter material and its preparation method. Using sepiolite fiber as a skeleton, it is composited with polydimethylsiloxane to prepare a coating with low surface energy, good air permeability, and strong anti-adhesion properties. This coating is then applied to the surface of a high-flux PPS coated filter material using a spraying method, enhancing the filter material's anti-adhesion performance and extending its lifespan. This filter material meets the requirements for long-term stable operation in high-temperature, high-humidity flue gas environments containing sticky substances, providing a more efficient and environmentally friendly technical solution for industrial flue gas purification.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for preparing a fluorine-free high-flux anti-adhesion fiber membrane filter material includes the following preparation steps:

[0008] (1) Preparation of hydrophobic sepiolite fiber: sepiolite powder was added to a hydrochloric acid solution with a mass fraction of 1% to 4% to disintegrate it, and after washing, drying and grinding, acidified sepiolite fiber was obtained; the acidified sepiolite fiber was dispersed in anhydrous ethanol, a silane coupling agent was added and reacted at 60 to 90 °C for 3 to 10 h, and after washing, drying and grinding, hydrophobic sepiolite fiber was obtained (the sepiolite fiber was alkylated and grafted with an alkyl coupling agent).

[0009] (2) Preparation of sepiolite dispersion: The hydrophobic sepiolite fiber obtained in step (1) and polydimethylsiloxane are added to n-hexane, ultrasonically dispersed, and then a curing agent is added and stirred evenly. Then a wetting agent and an antistatic agent are added and stirred evenly to obtain a composite functional coating liquid.

[0010] (3) Preparation of membrane filter material: Polyphenylene sulfide meltblown fiber membrane or polyphenylene sulfide hydroentangled membrane is hot-pressed with polyphenylene sulfide needle-punched felt using a membrane coating machine to obtain high-flux membrane filter material;

[0011] (4) Spraying and curing of anti-adhesion coating: After ultrasonic cleaning and drying of the high-flux membrane filter material obtained in step (3), the composite functional coating liquid obtained in step (2) is sprayed onto the membrane surface of the clean membrane filter material. After standing at room temperature until the hexane evaporates, it is cured in an oven to obtain the high-flux anti-adhesion fiber membrane filter material.

[0012] Further, in step (1), the solid-liquid ratio of the sepiolite powder to the hydrochloric acid solution is 1:20 to 1:25; the silane coupling agent is one or more of dodecyltriethoxysilane, octyltriethoxysilane, methyltrimethoxysilane, ethyltriethoxysilane, and hexadecyltrimethoxysilane; the mass ratio of the silane coupling agent to the acidified sepiolite fiber is 1.5:1 to 3:1, and the solid-liquid ratio of the acidified sepiolite fiber to anhydrous ethanol is 1:50 to 1:70.

[0013] Furthermore, the washing, drying and grinding steps in step (1) involve washing with deionized water until the filtrate is neutral, then drying at 80~100 ℃ to constant weight, and grinding with an agate mortar for 20~30 min.

[0014] Furthermore, the polydimethylsiloxane mentioned in step (2) is selected from two-component thermosetting or condensation-curing silicone rubber, such as Dow Corning 184 series or Shin-Etsu KE series; the curing agent is one of the platinum curing agent or organotin curing agent that is compatible with silicone rubber, and the amount added is 5% to 20% of the mass of polydimethylsiloxane; the solid-liquid ratio of hydrophobic sepiolite fiber and polydimethylsiloxane to n-hexane is (7~10):100.

[0015] Furthermore, the wetting agent mentioned in step (2) is any one of CAD-W-8378, JH-420, TEGO 245, HT-198, HT-105, OT-75, and PE-100, and its addition amount is 1% to 5% of the mass of polydimethylsiloxane; the antistatic agent is any one or two of TX-10 and HS-BM02, and its addition amount is 0.5% to 1% of the mass of polydimethylsiloxane.

[0016] Furthermore, the thickness of the polyphenylene sulfide meltblown fiber membrane or hydroentangled membrane mentioned in step (3) is 45~55 μm, and the air permeability is 240~260 L / dm. 2 The diameter is 5~8 μm; the thickness of the polyphenylene sulfide needle-punched felt is 1.40~1.55 mm, and the air permeability is 90~130 L / dm. 2 The hot pressing temperature is 130~170 ℃, the hot roller speed is 1~4 m / min, and the pressure is 0.2~0.4 MPa.

[0017] Furthermore, in step (4), the time spent at room temperature is 20~40 min, the curing temperature is 100~140 ℃, and the curing time is 1~4 h.

[0018] Furthermore, in step (4), the loading amount of the composite functional coating liquid sprayed on the membrane surface of the clean membrane filter material is 8~15 g / m. 2 The ultrasonic cleaning time is 30-60 min, the drying temperature is 100-120 ℃, and the drying time is 4 h; the room temperature standing time is 30 min, the curing temperature is 100-140 ℃, and the curing time is 2-4 h.

[0019] This invention further provides a high-flux anti-adhesion fiber membrane filter material with a three-dimensional breathable coating structure. The three-dimensional breathable network structure is composed of hydrophobic sepiolite fibers coated with polydimethylsiloxane. The coated fibers are randomly and interwoven on the surface of the polyphenylene sulfide meltblown fiber membrane, forming a three-dimensional interconnected pore structure between the fibers. Specifically, the anti-adhesion coating is not a dense, continuous membrane layer, but a micro / nano fiber particle-polymer composite network structure composed of hydrophobically modified sepiolite fibers (DSEP) and polydimethylsiloxane (PDMS). The hydrophobically modified sepiolite fibers serve as the skeletal support, and their surface is coated with PDMS low surface energy material. Multiple coated fibers are interwoven on the surface of the meltblown fiber membrane, forming a breathable coating with three-dimensional interconnected pores. This structural design avoids direct loading of PDMS, which would clog the filtration channels on the surface of the filter media fiber membrane. By existing in the form of "fiber surface coating - fiber overlap", it not only gives the filter media excellent anti-adhesion properties, but also retains the original high-flux characteristics of the filter media substrate to the maximum extent.

[0020] The aforementioned fluorine-free, high-flux, anti-adhesion fiber membrane filter material can be applied to high-temperature flue gas dust removal, especially in environments with high humidity dust or ammonium bisulfate condensation.

[0021] The present invention has the following advantages:

[0022] (1) This invention uses sepiolite, a natural fibrous silicate mineral, which has a unique nanofiber structure and its morphology is highly matched with the fiber network of the fiber membrane on the filter material surface. Introducing hydrophobically modified sepiolite fibers into the coating system can form a synergistic effect with polydimethylsiloxane: on the one hand, it provides abundant adhesion sites and support skeleton for low surface energy PDMS, significantly reducing the PDMS loading and mitigating its physical blockage of fiber channels while ensuring the same anti-adhesion effect, thus maximizing the maintenance of the original air permeability of the filter material; on the other hand, DSEP can construct a micro-nano multi-level structure on the coating surface, improve the surface roughness, and further weaken the adhesion of sticky pollutants to the filter material surface. The filter material prepared in this way has an anti-adhesion coating formed by the interlaced stacking of hydrophobically modified sepiolite fibers coated with PDMS to form a three-dimensional air permeable network structure. This structural design enables the filter material to obtain high hydrophobicity (water contact angle > 133°) and excellent anti-adhesion properties while maximizing the preservation of the high flux characteristics (air permeability > 64 L / dm) of the filter material substrate. 2 ( / min), which solves the technical problem that traditional functional coatings easily clog the pores of micro and nanofiber membranes.

[0023] (2) The filter material prepared by the present invention has excellent performance, low dynamic filtration resistance, high dust stripping rate, and filtration efficiency >99.99%.

[0024] (3) It has good high temperature resistance and can be used for a long time below 160 ℃, making it suitable for complex flue gas environments.

[0025] (4) The core functional materials selected in this invention are polydimethylsiloxane (PDMS) and modified sepiolite fiber, both of which are fluorine-free. This avoids the environmental and health risks that may be caused by traditional fluorinated hydrophobic filter materials (such as PTFE) during production, use and disposal, thus achieving an environmental protection closed loop and meeting the requirements of green chemical industry and sustainable development. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating the preparation process of the fluorine-free high-flux anti-adhesion fiber membrane filter material in Embodiment 2 of the present invention.

[0027] Figure 2 The infrared spectrum of the hydrophobically modified sepiolite fiber in Example 2 of this invention.

[0028] Figure 3 This is a water wetting angle image of the fluorine-free high-flux anti-adhesion fiber membrane filter material in Embodiment 2 of the present invention.

[0029] Figure 4 The pore size distribution diagrams are shown for the fluorine-free high-flux anti-adhesion fiber membrane filter materials in Examples 1-3 and Comparative Example 1 of the present invention.

[0030] Figure 5 Scanning electron microscope image of the high-throughput anti-adhesion fiber membrane filter material prepared in Example 2.

[0031] Figure 6 The adhesion of ammonium bisulfate in Comparative Examples 1 (a1~a4) and Example 2 (b1~b4) of the present invention is shown.

[0032] Figure 7 The condensation of ammonium bisulfate is shown in Comparative Example 1 and Example 2 of this invention.

[0033] Figure 8 The changes in residual mass of ammonium bisulfate in Comparative Example 1 and Example 2 of this invention are shown. Detailed Implementation

[0034] The technical solutions of the present invention will be described in detail below through embodiments. The following embodiments are merely exemplary and can only be used to explain and illustrate the technical solutions of the present invention, and should not be construed as limiting the technical solutions of the present invention.

[0035] Unless otherwise specified, all raw materials used in this embodiment can be obtained through commercial channels.

[0036] like Figure 1 As shown, the preparation method of the fluorine-free high-flux anti-adhesion PPS fiber membrane filter material provided in this embodiment of the invention includes the following steps:

[0037] S1: Preparation of hydrophobically modified sepiolite fiber;

[0038] S2: Preparation of PDMS / DSEP composite functional coating solution;

[0039] S3: Hot pressing lamination of PPS fiber membrane and needle-punched felt;

[0040] S4: Spraying and curing of anti-adhesion functional coating.

[0041] The polyphenylene sulfide meltblown fiber membranes or hydroentangled membranes involved in the following examples and comparative examples have a thickness of 45~55 μm and an air permeability of 240~260 L / dm. 2 / min, diameter 5~8 μm; polyphenylene sulfide needle-punched felt thickness 1.40~1.55 mm, air permeability 90~130 L / dm 2 / min.

[0042] The present invention will be further described below with reference to specific embodiments.

[0043] Example 1

[0044] A method for preparing a fluorine-free high-flux anti-adhesion fiber membrane filter material, comprising the following specific steps:

[0045] 5.0 g of sepiolite powder was stirred with 100 mL of 3% hydrochloric acid solution for 4 hours. The product was washed repeatedly with deionized water and filtered until the filtrate was neutral. Then, it was dried in an oven at 80-100 °C to constant weight and ground with an agate mortar for 20-30 min to obtain acidified sepiolite fiber. 30 parts by weight of acidified sepiolite fiber and 70 parts by weight of hexadecyltrimethoxysilane were dispersed in 2000 parts by weight of anhydrous ethanol and stirred at 70 °C for 6 hours. After washing, drying, and grinding, hydrophobically modified sepiolite fiber (DSEP) was obtained.

[0046] Take 40 parts by weight of the above-mentioned hydrophobic modified sepiolite fiber and 60 parts by weight of Dow Corning 184 silicone rubber (polydimethylsiloxane), add them to 1000 parts by weight of n-hexane, and ultrasonically disperse for 30 minutes. Then add 6 parts by weight of silicone rubber curing agent, stir and mix evenly, then add 2 parts by weight of wetting agent CAD-W-8378 and 1 part by weight of antistatic agent TX-10 and continue stirring evenly to obtain the composite functional coating liquid.

[0047] A 20×25 cm PPS meltblown fiber membrane was aligned with a PPS needle-punched felt and hot-pressed at 160℃, 0.30 MPa, and a hot roller speed of 2 m / min to obtain a PPS membrane-coated filter material substrate. The PPS membrane-coated filter material substrate was ultrasonically cleaned with anhydrous ethanol for 30 min to remove fine particles and grease from the surface and internal pores of the filter material. It was then dried in a 100℃ oven for 4 h, and the weight was recorded. The above-mentioned composite functional coating liquid was sprayed onto the surface of the PPS membrane-coated filter material substrate using a spray gun. After being left at room temperature for half an hour, it was cured in an oven at 120℃ for 2 h to obtain a fluorine-free, high-flux, anti-adhesion functional filter material. The loading of the composite functional coating liquid was 9.5 g / m³. 2 .

[0048] Example 2

[0049] A method for preparing a fluorine-free high-flux anti-adhesion fiber membrane filter material, comprising the following specific steps:

[0050] 5.0 g of sepiolite powder was reacted with 100 mL of 4% hydrochloric acid solution for 2 hours. The product was washed repeatedly with deionized water and filtered until the filtrate was neutral. Then, it was dried in an oven at 80-100 °C to constant weight and ground in an agate mortar for 20-30 min to obtain acidified sepiolite fiber. 40 parts by weight of acidified sepiolite fiber and 60 parts by weight of dodecyltriethoxysilane were dispersed in 2000 parts by weight of anhydrous ethanol and stirred at 80 °C for 6 hours. After washing, drying, and grinding, hydrophobically modified sepiolite fiber (DSEP) was obtained.

[0051] Take 30 parts by weight of the above-mentioned hydrophobic modified sepiolite fiber and 60 parts by weight of Dow Corning 184 silicone rubber, add them to 1000 parts by weight of n-hexane, ultrasonically disperse for 30 minutes, then add 1 part by weight of silicone rubber curing agent, stir for 30 minutes, then add 1 part by weight of wetting agent CAD-W-8378 and 1 part by weight of antistatic agent HS-B2 and continue stirring for 30 minutes to obtain the composite functional coating liquid.

[0052] A 20×25 cm PPS meltblown fiber membrane was aligned with a PPS needle-punched felt and hot-pressed at 160℃, 0.30 MPa, and a hot roller speed of 2 m / min to obtain a PPS membrane-coated filter material substrate. The PPS membrane-coated filter material substrate was ultrasonically cleaned with anhydrous ethanol for 30 min to remove fine particles and grease from the surface and internal pores of the filter material. It was then dried in a 100℃ oven for 4 h, and the weight was recorded. The above-mentioned composite functional coating liquid was sprayed onto the surface of the PPS membrane-coated filter material substrate using a spray gun. After being left at room temperature for half an hour, it was cured in an oven at 120℃ for 2 h to obtain a fluorine-free, high-flux, anti-adhesion functional filter material. The loading of the composite functional coating liquid was 11.4 g / m³. 2 .

[0053] Example 3

[0054] A method for preparing a fluorine-free high-flux anti-adhesion fiber membrane filter material, comprising the following specific steps:

[0055] 5.0 g of sepiolite powder was reacted with 100 mL of 4% hydrochloric acid solution for 2 hours. The product was washed repeatedly with deionized water and filtered until the filtrate was neutral. Then, it was dried in an oven at 80-100 °C to constant weight and ground in an agate mortar for 20-30 min to obtain acidified sepiolite fiber. 30 parts by weight of acidified fiber and 70 parts by weight of octyltriethoxysilane were dispersed in 2000 parts by weight of anhydrous ethanol and reacted at 80 °C for 4 hours. After washing, drying, and grinding, hydrophobically modified sepiolite fiber (DSEP) was obtained.

[0056] Take 40 parts by weight of the hydrophobic modified sepiolite fiber and 60 parts by weight of Dow Corning 184 silicone rubber, add them to 1000 parts by weight of n-hexane, ultrasonically disperse for 30 minutes, then add 1 part by weight of silicone rubber curing agent, stir and mix evenly, then add 1 part by weight of wetting agent OT-75 and 1 part by weight of antistatic agent HS-B2 and continue stirring evenly to obtain composite functional coating liquid.

[0057] A 20×25 cm PPS meltblown fiber membrane was aligned with a PPS needle-punched felt and hot-pressed at 160℃, 0.30 MPa, and a hot roller speed of 2 m / min to obtain a PPS membrane-coated filter material substrate. The PPS membrane-coated filter material substrate was ultrasonically cleaned with anhydrous ethanol for 30 min to remove fine particles and grease from the surface and internal pores of the filter material. It was then dried in a 100℃ oven for 4 h, and the weight was recorded. The above-mentioned composite functional coating liquid was sprayed onto the surface of the PPS membrane-coated filter material substrate using a spray gun. After being left at room temperature for half an hour, it was cured in an oven at 120℃ for 2 h to obtain a fluorine-free, high-flux, anti-adhesion functional filter material. The loading of the composite functional coating liquid was 13.3 g / m³. 2 .

[0058] Figure 2 The infrared spectrum of the hydrophobic modified sepiolite fiber in Example 2 shows that the hydrophobic sepiolite fiber was successfully alkylated.

[0059] Figure 3 The image shows the water wetting angle of the fluorine-free high-flux anti-adhesion fiber membrane filter material in Example 2. The results indicate that the prepared high-flux anti-adhesion PPS functional filter material has good hydrophobicity.

[0060] Figure 4The diagram shows the pore size distribution of the filter materials prepared in Examples 1-3 and Comparative Example 1. The pore size distribution of the high-flux anti-adhesion PPS functional filter material prepared by the method of the present invention shows a trend of shrinkage and leftward shift compared with the original filter material (Comparative Example 1), which can reduce the infiltration of water and oily liquids while maintaining the original high-flux characteristics.

[0061] Figure 5 The scanning electron microscope (SEM) image of the high-flux anti-adhesion fiber membrane filter material prepared in Example 2 shows that the surface of the hydrophobically modified sepiolite fibers (DSEP) is uniformly coated with a PDMS layer. These fibers are randomly and interwoven on the surface of the PPS membrane layer, forming numerous three-dimensional interconnected pores between them. This structural feature indicates that the anti-adhesion coating of the present invention is not a dense membrane layer, but a porous network structure composed of a "fiber skeleton + surface coating layer." This allows for the provision of high anti-adhesion properties to the membrane filter material while maximizing the high air permeability of the substrate.

[0062] Comparative Example 1

[0063] A 20×25 cm PPS meltblown fiber membrane was aligned with a PPS needle-punched felt and hot-pressed at 160℃, 0.20 MPa and hot roller speed of 2 m / min to obtain a PPS membrane filter material substrate.

[0064] The PPS-coated filter media substrate was ultrasonically cleaned with anhydrous ethanol for 20 min to remove fine particles and grease from the surface and internal pores of the filter media. It was then dried in a 100 ℃ oven for 2 h, and then dried in a vacuum drying oven at 120 ℃ to remove internal moisture, thus preparing the PPS-coated filter media.

[0065] Application Example Performance Testing

[0066] 1. Dust removal performance test

[0067] The fluorine-free high-flux anti-adhesion functional filter media prepared in the examples and the PPS membrane filter media prepared in the comparative examples were subjected to VDI filtration-cleaning experiments to examine the cleaning performance of the obtained functional filter media. The specific experimental procedures are as follows:

[0068] The dust removal performance of the above-mentioned functional filter material and the original filter material was tested by a dust filtration efficiency testing system to evaluate the dust removal performance of the prepared functional filter material. The results are shown in Table 1.

[0069] Table 1. Filtration performance of the filter media prepared in Examples 1-3 and Comparative Example 1

[0070]

[0071] Table 1 shows that when the load is 5~20 g / m 2Within this range, as the loading rate increases, the residual pressure drop of the fluorine-free high-flux anti-adhesion filter media is lower than that of the uncoated anti-adhesion coating. Example 2: Loading rate 11.4 g / m³ 2 The anti-adhesion filter media exhibits the best dust removal performance. Its residual pressure drop at the 30C1, 10000 aging, and 30C2 stages is reduced by 17.5%, 24.2%, and 24.8% compared to the original filter media, respectively. This phenomenon is likely due to the introduction of low surface energy materials, which improves dust removal performance to a certain extent, reduces dust adhesion, and allows for more thorough dust removal during the pulse-jet cleaning process, resulting in a decreasing trend in residual pressure drop and improved dust removal performance. Furthermore, with the increase in finishing material, the impact on air permeability is minimal, maintaining the original high-flux characteristics of the filter media (>50 L / dm³). 2 / min).

[0072] 2. Water contact angle test

[0073] The water contact angles of the fluorine-free high-flux anti-adhesion functional filter media prepared in Examples 1, 2, and 3, and the PPS membrane filter media prepared in Comparative Example 1, are shown in the table below:

[0074] Table 2. Water contact angles of filter media prepared in Examples 1-3 and Comparative Example 1

[0075]

[0076] As shown in Table 2, the water contact angle of the fluorine-free high-flux anti-adhesion filter media gradually increases with the increase of loading. This is mainly attributed to the extremely low surface energy of PDMS itself. Its Si-O-Si backbone and terminal methyl groups (-CH3) can effectively reduce the surface free energy of the material, which is the basis for its hydrophobicity. Secondly, fibrous modified sepiolite (DSEP) constructs a micro-nano-scale rough structure in the PDMS matrix.

[0077] 3. Dust-Ammonium Bisulfate Adhesion Test

[0078] Given the limited number of direct evaluation methods for the retention and adhesion behavior of molten ABS on dust-laden filter media, this application designs a simulated ABS condensation and adhesion experiment based on actual working conditions. A rectangular filter media sample of 2 cm × 6 cm was cut from the filter media (with a certain amount of residual dust on the surface) after the VDI dynamic filtration performance test. The filter media was fixed on a sample stage at a certain tilt angle, with the test surface facing upwards. 1.0 g of ammonium bisulfate (NH4HSO4, analytical grade) was weighed and placed in a beaker, and heated to 150 °C along with the filter media in an oven until the ammonium bisulfate was completely melted into a liquid state. Subsequently, the molten ammonium bisulfate was slowly poured over the sample surface, allowing it to flow over the entire sample surface. After the filter media cooled naturally to room temperature, the mass change of the sample before and after the test was measured using a precision electronic balance, and the weight gain (Δm, g) was recorded. Each sample was tested in parallel three times, and the average value was taken. By comparing the weight gain of the coated functional filter media and the original filter media, the anti-adhesion performance of the filter media to molten ABS is quantitatively evaluated (the smaller the weight gain, the better the anti-adhesion performance).

[0079] Depend on Figure 6 and Figure 7 It can be seen that Comparative Example 1 and Example 2 exhibit two different situations regarding the dripping of molten ammonium bisulfate: Comparative Example 1 has a large amount of white ABS condensate remaining on the surface, covering a wide area and bonding firmly; while the surface of Example 2 remains basically clean, with only a very small amount of residue at the edges.

[0080] Depend on Figure 8 The sample weight gain data further quantitatively confirmed this phenomenon. The weight gain of Comparative Example 1 was 0.17 g, while the weight gain of Example 2 was significantly reduced to close to 0 g, a decrease of more than 90%. Considering that this experiment mainly reflects trend differences, the above results still clearly show that under the same experimental conditions, the anti-adhesion functional filter material can significantly inhibit the retention and adhesion of molten ABS on the surface of the dust-laden filter material.

[0081] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements 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 fluorine-free high-flux anti-adhesion fiber membrane filter material, characterized in that: The preparation steps include the following: (1) Preparation of hydrophobic sepiolite fiber: sepiolite powder was added to a hydrochloric acid solution with a mass fraction of 1% to 4% to disintegrate it, and after washing, drying and grinding, acidified sepiolite fiber was obtained; the acidified sepiolite fiber was dispersed in anhydrous ethanol, a silane coupling agent was added, and the reaction was carried out at 60 to 90 °C for 3 to 10 h, and after washing, drying and grinding, hydrophobic sepiolite fiber was obtained. (2) Preparation of sepiolite dispersion: The hydrophobic sepiolite fiber obtained in step (1) and polydimethylsiloxane are added to n-hexane, ultrasonically dispersed, and then a curing agent is added and stirred evenly. Then a wetting agent and an antistatic agent are added and stirred evenly to obtain a composite functional coating liquid. (3) Preparation of membrane filter material: Polyphenylene sulfide meltblown fiber membrane or polyphenylene sulfide hydroentangled membrane is hot-pressed with polyphenylene sulfide needle-punched felt using a membrane coating machine to obtain high-flux membrane filter material; (4) Spraying and curing of anti-adhesion coating: After ultrasonic cleaning and drying of the high-flux membrane filter material obtained in step (3), the composite functional coating liquid obtained in step (2) is sprayed onto the membrane surface of the clean membrane filter material. After standing at room temperature until the hexane evaporates, it is cured in an oven to obtain the high-flux anti-adhesion fiber membrane filter material.

2. The preparation method according to claim 1, characterized in that: In step (1), the solid-liquid ratio of sepiolite powder to hydrochloric acid solution is 1:20 to 1:25; the silane coupling agent is one or more of dodecyltriethoxysilane, octyltriethoxysilane, methyltrimethoxysilane, ethyltriethoxysilane, and hexadecyltrimethoxysilane; the mass ratio of silane coupling agent to acidified sepiolite fiber is 1.5:1 to 3:1, and the solid-liquid ratio of acidified sepiolite fiber to anhydrous ethanol is 1:50 to 1:

70.

3. The preparation method according to claim 1, characterized in that: The washing, drying and grinding steps in step (1) are as follows: wash with deionized water until the filtrate is neutral, then dry at 80~100 ℃ to constant weight, and grind with an agate mortar for 20~30 min.

4. The preparation method according to claim 1, characterized in that: The polydimethylsiloxane mentioned in step (2) is selected from two-component thermosetting or condensation-curing silicone rubber; the curing agent is one of the platinum curing agent or organotin curing agent that is matched with silicone rubber, and the amount added is 5% to 20% of the mass of polydimethylsiloxane; the solid-liquid ratio of hydrophobic sepiolite fiber and polydimethylsiloxane to n-hexane is (7~10):

100.

5. The preparation method according to claim 1, characterized in that: The wetting agent mentioned in step (2) is any one of CAD-W-8378, JH-420, TEGO 245, HT-198, HT-105, OT-75, and PE-100, and its addition amount is 1% to 5% of the mass of polydimethylsiloxane; the antistatic agent is any one or two of TX-10 and HS-BM02, and its addition amount is 0.5% to 1% of the mass of polydimethylsiloxane.

6. The preparation method according to claim 1, characterized in that: The polyphenylene sulfide meltblown fiber membrane or hydroentangled membrane mentioned in step (3) has a thickness of 45~55 μm and an air permeability of 240~260 L / dm. 2 The diameter is 5~8 μm; the thickness of the polyphenylene sulfide needle-punched felt is 1.40~1.55 mm, and the air permeability is 90~130 L / dm. 2 / min; the temperature of the hot pressing composite is 130~170℃, the hot roller speed is 1~4 m / min, and the pressure is 0.2~0.4 MPa.

7. The preparation method according to claim 1, characterized in that: In step (4), the loading amount of the composite functional coating liquid sprayed on the membrane surface of the clean membrane filter material is 5~18 g / m. 2 The ultrasonic cleaning time is 30-60 min, the drying temperature is 100-120 ℃, and the drying time is 4 h; the room temperature standing time is 30 min, the curing temperature is 100-140 ℃, and the curing time is 2-4 h.

8. A fluorine-free high-flux anti-adhesion fiber membrane filter material prepared by the preparation method according to any one of claims 1 to 7.

9. The fluorine-free high-flux anti-adhesion fiber membrane filter material according to claim 8, characterized in that: The anti-adhesion coating of the filter material has a three-dimensional air-permeable network structure; the three-dimensional air-permeable network structure is composed of hydrophobic sepiolite fibers coated with polydimethylsiloxane. The coated fibers are randomly stacked on the surface of the polyphenylene sulfide meltblown fiber membrane, forming a three-dimensional interconnected pore structure between the fibers.

10. The application of the fluorine-free high-flux anti-adhesion fiber membrane filter material according to claim 8 in high-temperature flue gas dust removal.

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