Dust removal filter material with anti-condensation and self-cleaning properties and preparation method thereof

Abstract

The present invention discloses a dust removal filter material with anti-condensation and self-cleaning properties and a preparation method thereof, relating to the technical field of filter materials. The filter material is composed of a filter material body and a surface treatment layer. The filter material body fiber can be selected from a variety of materials. The surface treatment layer is mainly composed of perfluoro and polyfluoroalkyl compounds containing straight-chain carbon atoms, organic fluorine-silicon modified acrylate compounds and ethoxylated non-ionic fluorocarbon surfactants. The preparation method includes the preparation of the filter material body, the preparation of the surface coating treatment liquid, the surface coating spraying and the drying and shaping treatment. The present invention can effectively improve the performance of the filter material under complex working conditions, and has good comprehensive properties such as anti-condensation, self-cleaning, waterproof and oil-proof, and filtering in high temperature, high humidity or oil-containing environments. The filter material has a water repellency level of 4 or above, and an oil repellency level of 7 or above. It can effectively reduce the outlet concentration, increase the cycle time, and the dust removal rate can reach more than 99.99%.

Description

Technical Field

[0001] The present invention relates to the technical field of filter materials, in particular to a dust removal filter material with anti-condensation and self-cleaning properties and a preparation method thereof. Background Art

[0002] Bag filters, with their efficient dust removal capabilities, simple structure, and convenient maintenance, are widely used in industries such as coal-fired power plants, steel smelting, cement production, and glass manufacturing. However, in actual operation, due to complex and changing operating conditions, filter bags are often affected by factors such as moisture, oil mist, and high temperatures, resulting in decreased filter media performance or even failure. Among these, the "bag sticking" problem is particularly prominent and has become one of the major challenges limiting the stable operation of bag filters. "Bag sticking" refers to the phenomenon in which, in high humidity environments or flue gases containing oily substances, dust adheres to the dust-facing surface of the filter media or internal fibers, clogging the filter media pores, causing a sharp drop in air permeability and a significant increase in equipment resistance. This not only directly affects the dust collector's operating efficiency, but also increases energy consumption, shortens filter bag life, and even leads to system downtime and high maintenance costs due to frequent filter bag replacements.

[0003] Currently, the industry's main methods for addressing the "bag-sticking" problem include coating and impregnation treatments, adding chemical water- and oil-repellent agents, and laminating treatments. Although these technologies have alleviated the "bag-sticking" problem to a certain extent, their effectiveness is often limited by the operating environment. In particular, in high-temperature, high-humidity, or oil-containing environments, conventional treatment methods make it difficult for existing filter bag materials to maintain their anti-condensation and anti-adhesion capabilities over the long term. Field application feedback and laboratory high-temperature testing have shown that the water- and oil-proof grades are prone to failure at certain temperatures. Therefore, there is an urgent need for a new filter material that combines anti-condensation, self-cleaning capabilities, and durable oil-proof properties to meet the needs of use in complex working conditions and effectively solve the "bag-sticking" problem.

[0004] Chinese patent publication number CN115970395A discloses a method for treating polyester filter media to make it waterproof and wear-resistant, and the filter media prepared therefrom. The method prepares and uses a nano-silica aerogel / waterproof and oil-proof composite impregnation liquid to impregnate the polyester filter media, thereby achieving a simultaneous increase in the wear resistance and waterproof properties of the polyester filter media. The main focus of the patent may be on achieving simultaneous improvement in the wear resistance and waterproof properties of the filter media, but it ignores the oil-proof properties of the filter media and its long-term effectiveness at high temperatures.

[0005] Chinese patent publication number CN102392355A discloses a method for preparing water- and oil-repellent, easy-to-clean filter media. This method utilizes a composite of PTFE emulsion and long-chain alkyl silicone oil for conventional impregnation of the filter media to achieve water- and oil-repellency. However, in real industrial environments, dust particles are complex and diverse in composition, including viscous components and chemically active substances. Relying solely on the water- and oil-repellent properties of PTFE emulsion to prevent dust bagging is insufficient. The water- and oil-repellent properties of PTFE emulsion cannot effectively prevent dust agglomeration and adhesion, resulting in dust bagging. Summary of the Invention

[0006] The purpose of the present invention is to solve the above technical problems and provide a dust removal filter material with anti-condensation and self-cleaning properties and a preparation method thereof. Through specific surface treatment, it can effectively overcome the defects of the existing technology, meet the needs of complex working conditions and solve the problem of "bag sticking".

[0007] In order to achieve the above technical objectives and meet the above technical requirements, the technical solution adopted by the present invention is: a dust removal filter material with anti-condensation and self-cleaning properties, the filter material is composed of a filter material body and a surface treatment layer; the filter material body is a filter felt prepared by a needle punching process;

[0008] The surface treatment layer contains at least one component, which is a perfluoroalkyl compound containing a straight chain of carbon atoms. The compound is evenly covered on the surface of the fiber layer, and the solid attachment amount of the compound on the filter material is 5 to 40 g / m 2 The surface treatment component uniformly covers the fiber surface at a thickness of 0-50 microns and covers at least 90% of the fiber surface area; at a thickness of 50-100 microns below the surface, the surface treatment component covers at least 75% of the fiber surface area; at a thickness of less than 200 microns below the surface, the surface treatment component covers less than or equal to 20% of the fiber surface area.

[0009] The perfluoroalkyl and polyfluoroalkyl compounds having a linear carbon chain in the surface treatment layer preferably have a linear carbon chain of six or more carbon atoms.

[0010] The surface treatment layer also contains an organic fluorine-silicon modified acrylate compound, which is an antifouling soft composite modifier with a solid attachment amount of 2 to 10 g / m 2 .

[0011] The surface treatment layer also contains an ethoxylated nonionic fluorocarbon surfactant with a solid attachment amount of 1 to 3 g / m².

[0012] The fibers constituting the main body of the filter material are preferably a mixture of one or more of PPS fibers, aramid fibers, glass fibers, basalt fibers, polyimide, polytetrafluoroethylene, and the like.

[0013] The method for preparing the dust removal filter material having anti-condensation and self-cleaning properties comprises the following steps:

[0014] Step 1: Preparation of filter material: Select fibers and base fabrics, open, mix, finely open, comb, lay nets, add base fabrics, and needle punch the short fibers to make semi-finished needle-punched felt. The unit weight is controlled at 400-900g / m 2 , and perform different post-treatments on the prepared filter felt such as singeing, calendering, heat setting, etc. according to needs;

[0015] Step 2: Prepare the surface coating treatment liquid. The liquid is configured according to the mass of solid adhesion on the filter media surface: 5-40g / m² of linear carbon atom perfluoro and polyfluoroalkyl compounds, 2-10g / m² of organic fluorine-silicon modified acrylate compounds, 1-3g / m² of ethoxylated non-ionic fluorocarbon surfactants. Some crosslinking agents and stabilizers can also be added to the prepared treatment liquid, and the rest is water.

[0016] Step 3: Surface coating spraying, evenly apply it on the surface of the high-temperature resistant fiber layer by spraying. The spraying distance during the spraying process is between 15cm-30cm, and the spraying inclination angle is less than or equal to 45 degrees before and after the vertical direction of the filter material. The relative humidity is between 40% and 70%, and the ambient temperature is controlled between 10℃ and 35℃.

[0017] Step 4: Dry and shape the prepared filter material to improve its performance stability; the drying and shaping temperature is preferably in three temperature ranges: Zone 1: 80℃~120℃, treatment time is 1~2 minutes; Zone 2: 120℃~160℃, treatment time is 1~2 minutes; Zone 3: 160℃~220℃, treatment time is 5~10 minutes.

[0018] The crosslinking agent in the above step 2 is preferably a silane coupling agent, and the added content is 1-3%; the stabilizer is preferably one of butylated hydroxyanisole (BHA) or BHT (tert-butylhydroquinone), and the added content is 0.5-2%.

[0019] The dust removal filter material has anti-condensation and self-cleaning properties. The waterproof and oil-proof grades of the filter material are tested based on GB / T4745-2012 "Test and evaluation of the waterproof performance of textiles - Water immersion method". The water repellency grade of the filter material is above level 4, and the oil repellency grade can reach above level 7.

[0020] The dust removal filter material with anti-condensation and self-cleaning properties adopts VDI3926-1:2004 "Testing of cleanable filter media - Standard test for the evaluation of cleanable filter media" for filtration performance evaluation, and the dust removal rate can reach more than 99.99%.

[0021] Compared with the traditional structure, the present invention has the following advantages:

[0022] 1. The surface treatment layer of the present invention achieves gradient coverage on the surface of the filter material, which can achieve higher levels of waterproof, oil-proof and anti-fouling properties, and can effectively improve the performance of the filter material under complex working conditions. In high temperature, high humidity or oil-containing environments, it has excellent anti-condensation, self-cleaning, waterproof and oil-proof and filtration comprehensive properties. It can achieve long-term and stable anti-condensation and anti-adhesion capabilities of the filter bag material, and effectively prevent filter bag sticking;

[0023] 2. The filter material of the present invention has a water repellency level of above 4 and an oil repellency level of above 7. It can effectively reduce the outlet concentration, increase the circulation time, and the dust removal rate can reach above 99.99%. It has broad application prospects in industrial dust removal and civilian fields. DETAILED DESCRIPTION

[0024] The present invention will be further described below.

[0025] A dust removal filter material with anti-condensation and self-cleaning properties, the filter material consisting of a filter material body and a surface treatment layer; the filter material body is a filter felt prepared by a needle punching process, and the unit weight is preferably 400-900g / m²; its fiber is preferably a mixture of one or more of PPS fiber, aramid fiber, glass fiber, basalt fiber, polyimide, polytetrafluoroethylene, etc.

[0026] Preparation method of dust removal filter material filter material body: select appropriate fibers (and base fabric), and make semi-finished needle-punched felt by subjecting the short fibers to processes such as opening, mixing, fine opening, carding, laying, adding base fabric, and needling.

[0027] The surface treatment layer of the filter material contains at least one component, which is a perfluoroalkyl compound containing a straight chain of carbon atoms, preferably a straight chain of six or more carbon atoms. The solid adhesion amount of the compound on the filter material is preferably 5 to 40 g / m 2Per- and polyfluoroalkyl compounds with straight carbon chains can form a dense and stable protective film on the surface of materials, significantly outperforming many common water repellents. Compared to common water repellents, their longer carbon chains result in stronger intermolecular forces, a tighter molecular arrangement, and a lower critical surface tension. The presence of fluorine atoms further enhances this effect. Fluorine atoms have a strong electronegativity, attracting electrons and creating a denser electron cloud around the molecules. This dense electron cloud structure increases the attraction between the molecular chains, resulting in a denser waterproof film. This film not only effectively blocks the penetration of water molecules but also repels oil molecules, giving the material excellent water and oil repellency. However, when the number of carbon atoms is less than six, the stability of its water and oil repellency is significantly reduced. Experiments have shown that when the solid deposition rate of per- and polyfluoroalkyl compounds with straight carbon chains on the filter media is between 5 and 40 g / m², the compounds form a uniform gradient covering structure between the fiber layers. When the adhesion level is less than 5g / m², a complete protective film cannot be formed, and the compound cannot fully cover the fiber surface, resulting in water and oil repellency that does not meet the requirements of this case. When the adhesion level is higher than 40g / m², on the one hand, it will block the pores between the fibers, affecting the air permeability of the filter material, resulting in high pressure drop during filtration, resulting in reduced filtration performance and increased energy consumption. On the other hand, excessive compound will cause accumulation on the material surface, forming an uneven coating, which in turn reduces the stability of the protective effect.

[0028] Its gradient attachment structure is: the fiber surface at a thickness of 0-50 microns is evenly covered, and the surface treatment component covers at least 90% of the fiber surface area. This area is the part that is in direct contact with the external environment and is the first line of defense against water and oil penetration. If the area is less than 90%, water molecules and oil molecules can easily enter the interior of the material through these gaps. This will result in the material's waterproof and oil-proof properties failing to meet the requirements, and once liquid enters, it will also affect the material's internal structure, such as causing fiber adhesion and easy dust penetration, and thus the filtration efficiency will also fail to meet the requirements; at a thickness of 50-100 microns below the surface, the surface treatment component covers at least 75% of the fiber surface area. Although this depth area is not directly exposed to the external environment, it is still affected by liquid penetration. If the coverage area is insufficient, due to the incompleteness of the protective layer, the liquid gradually penetrates into this area, resulting in the filtration performance failing to meet the requirements, resulting in an increase in the dust outlet concentration and an increase in pressure loss; at a thickness of less than 200 microns below the surface, the surface treatment component covers an area less than or equal to 20% of the fiber surface area. In this deeper area, the performance is mainly maintained by the material's own structure and the protection of the upper layer. If the coverage area is too large, the internal microstructure of the material will be excessively changed, causing the pores between the fibers to be blocked, resulting in the material's air permeability and filtration performance failing to meet the requirements. Moreover, too many compounds in this area will also increase the cost and weight of the material, which does not meet the requirements of practical applications.

[0029] The filter material surface also contains an organic fluorine-silicone-modified acrylate compound, with a preferred solid adhesion rate of 2-10 g / m² on the fiber surface. This organic fluorine-silicone-modified acrylate compound produces a synergistic effect with the aforementioned linear carbon-chain perfluoroalkyl and polyfluoroalkyl compounds (waterproofing agents). While the waterproofing agent primarily prevents water and oil penetration, the organic fluorine-silicone-modified acrylate compound further reduces dust adhesion on the filter material surface, achieving easy cleaning and low dust adhesion, forming a complementary protective system. For example, when the waterproofing agent prevents the penetration of liquids, the organic fluorosilicone modified acrylate compound can prevent dust and other solid dirt from being adsorbed on the fiber surface in a humid environment, thereby greatly improving the overall anti-fouling ability of the material. When the attachment amount of the organic fluorosilicone modified acrylate compound is less than 2g / m², it cannot evenly cover the fiber surface, and the anti-fouling performance is not significantly improved. When the attachment amount of the organic fluorosilicone modified acrylate compound is higher than 10g / m², excessive compounds accumulate on the fiber surface, destroying the original reasonable protective structure. While the cost increases, the anti-fouling effect will not be further improved, but the filtration efficiency will be reduced.

[0030] The filter material also contains an ethoxylated nonionic fluorocarbon surfactant, preferably with a solid attachment density of 1-3 g / m² on the fiber surface. Surfactants reduce the surface tension of solutions and alter the interfacial properties between the solution and the material. The surfactant forms an adsorption layer on the fiber surface, causing some solute molecules to preferentially adsorb there. As impregnation progresses, the surfactant's distribution gradient causes the adsorption and diffusion of solutes to follow a gradient, resulting in a highly concentrated impregnation layer on the surface. The degree of impregnation gradually decreases as the material deepens, creating a gradient stratification effect. This treatment results in a uniform surface treatment layer covering at least 90% of the fiber surface at a thickness of 0-50 microns. At a depth of 50-100 microns below the surface, the surface treatment component covers at least 75% of the fiber surface. At a depth of less than 200 microns below the surface, the surface treatment component covers less than or equal to 20% of the fiber surface. When the ethoxylated nonionic fluorocarbon surfactant attachment rate is less than 1g / m², the excessive amount of surfactant prevents a complete and effective adsorption layer from forming on the fiber surface. This results in insufficient reduction of the solution's surface tension, poor interfacial property modification, disordered and incomplete adsorption of solute molecules, and a failure to form an ideal concentration gradient during impregnation. Consequently, the coating struggles to achieve the desired gradient stratification effect, leading to a decrease in final product quality. Problems such as uneven coating thickness and inadequate internal impregnation can occur, impacting filter media performance, such as reduced filtration efficiency and stability. When the ethoxylated nonionic fluorocarbon surfactant attachment rate is greater than 3g / m², the excess surfactant creates an excessively thick adsorption layer on the fiber surface. This layer becomes too viscous, causing excessive surface aggregation of solute molecules, blocking surface channels and hindering proper diffusion into the material. Furthermore, this excessively thick adsorption layer can lead to uneven stress distribution within the coating, making it susceptible to cracking or flaking. At the same time, too much surfactant will increase production costs and have an adverse effect on subsequent processing and other product properties, such as making the air permeability of the filter material worse or making it easier to adsorb impurities during actual use.

[0031] Preparation of the surface coating treatment solution for dust removal filter materials: The following ingredients are formulated based on the amount of solids adhering to the filter media surface: 5-40 g / m² of linear perfluoroalkyl and polyfluoroalkyl compounds, preferably 2-10 g / m² of organofluorosilicone-modified acrylates, and 1-3 g / m² of ethoxylated nonionic fluorocarbon surfactants. A silane coupling agent (at a concentration of 1-3%), a stabilizer (BHA (butylated hydroxyanisole) or BHT (tert-butylhydroquinone) at a concentration of 0.5-2%, and the remainder (water) are optionally added to the treatment solution to create a surface coating treatment solution. The addition of a silane coupling agent facilitates uniform coating coverage on the fiber surface, adjusts the rheological properties of the coating solution, promotes the dispersion and distribution of various components, and facilitates the creation of a gradient stratification effect. Furthermore, the silane coupling agent on one end reacts with the hydroxyl groups on the fiber surface to form chemical bonds, while the organic group on the other end interacts with the organic components of the coating, significantly enhancing the bond between the coating and the fiber. When the addition level is less than 1%, the interface between the inorganic components and the organic coating on the filter media surface cannot be fully covered, resulting in insufficient adhesion between the coating and the filter media, and thus reduced filter media durability. Because the amount of silane coupling agent is too low, it cannot form sufficient chemical bonds or physical adsorption to enhance interfacial adhesion. When the addition level exceeds 3%, the excess silane coupling agent will form aggregates within the coating. These aggregates affect coating uniformity, causing localized changes in coating performance, reduced air permeability, and increased pressure drop. Excessive silane coupling agent also increases costs, reducing product cost-effectiveness. Stabilizers such as BHA (butylated hydroxyanisole) or BHT (tert-butylhydroquinone) are primarily used to prevent oxidation of coating components during storage or use. If the addition level is less than 0.5%, their antioxidant capacity is insufficient. In real-world environments, coating materials can undergo oxidation reactions due to exposure to oxygen, ultraviolet light, and other factors, leading to performance degradation such as discoloration and embrittlement. However, adding more than 2% can negatively impact other coating properties, such as altering the coating's chemical stability and causing adverse reactions with other ingredients. Excessive amounts of stabilizer can also increase production costs and affect the coating's physical properties, such as increasing hardness and reducing flexibility.

[0032] Spraying the surface coating of the dust removal filter material: The treatment liquid is evenly applied to the surface of the high-temperature resistant fiber layer by spraying. The spraying distance is preferably between 15cm and 30cm, and the spraying angle should be less than or equal to 45 degrees relative to the filter material. The relative humidity is preferably between 40% and 70%, and the ambient temperature is preferably between 10°C and 35°C. Extensive experiments have shown that these process parameters achieve the best gradient coating distribution. When the spraying distance is less than 15cm, the high-pressure treatment liquid sprayed from the spray gun has a strong impact and is difficult to disperse. This can lead to localized over-concentration of the sprayed liquid, resulting in uneven distribution. This can also cause the treatment liquid to penetrate deeper, making it less likely to concentrate on the fiber surface. This can affect coating uniformity and surface properties such as surface smoothness and gloss. Furthermore, a closer distance can result in excessively thick coating in some areas, which can easily cause defects such as cracking during drying, and also result in waste of treatment liquid. When the spraying distance is greater than 30cm, the treatment liquid will diffuse and disperse significantly before reaching the fiber surface, resulting in a reduction in the amount of treatment liquid effectively adhering to the fiber layer. This makes it difficult to achieve the desired coating thickness, affecting the coating's integrity and functionality. This prevents the formation of a continuous, uniform, and sufficiently thick protective coating, thereby reducing the filtration efficiency and service life of the dust filter material. When the spraying angle is greater than ±45 degrees, the treatment liquid is applied to the fiber surface in an excessively oblique direction, causing most of the treatment liquid to drift into the surrounding environment and fail to effectively coat the fiber surface. This prevents uniform adhesion and results in uneven coating thickness, with some areas potentially missing or too thin a coating. This in turn affects the overall performance of the dust filter material, such as its ability to intercept dust and other particulate matter and its ability to resist pollution. Most of the treatment liquid will drift into the surrounding environment and fail to effectively coat the fiber surface, resulting in significant waste of treatment liquid and environmental pollution. Furthermore, it completely prevents effective coating of the fiber layer, preventing the dust filter material from achieving the expected surface coating performance. When the relative humidity is below 40%, the environment is too dry, and the water in the treatment fluid evaporates quickly. This can cause the treatment fluid's viscosity to change during the spraying process, making it too thick, affecting its fluidity and atomization. This leads to uneven spraying and the formation of granules or lumps that accumulate on the fiber surface, rather than a uniform coating. This, in turn, affects the coating quality and the filtration performance of the dust removal filter material. When the relative humidity is above 70%, the ambient humidity is high, and the evaporation rate of the water in the treatment fluid slows down, resulting in a prolonged drying time for the coating. During the drying process, the coating is easily adsorbed with impurities and dust from the air, contaminating the coating surface. Furthermore, the high humidity environment affects the chemical reactivity of certain components in the treatment fluid, resulting in a decrease in the bonding strength between the coating and the fiber, and a decrease in the durability and stability of the coating.When the ambient temperature is below 10°C, the viscosity of the treatment liquid increases and its fluidity deteriorates, which is not conducive to atomization and uniform coating during the spraying process, resulting in uneven coating thickness, rough surface and other problems. At the same time, low temperatures will reduce the reactivity of some components in the treatment liquid, affecting the curing speed and quality of the coating, making the coating and the fiber bond weak, and reducing the performance and service life of the dust removal filter material. When the ambient temperature is above 35°C, the solvent and other components in the treatment liquid evaporate too quickly, causing the concentration of the treatment liquid to change during the spraying process, affecting its uniformity and stability, and easily causing defects such as uneven coating surface and bubbles. In addition, high temperature environments may cause some components in the treatment liquid to decompose or denature, destroying the structure and performance of the coating and reducing the protective effect and reliability of the dust removal filter material.

[0033] Surface Drying and Curing of Dust Removal Filter Material: The prepared filter material is dried and cured to improve its performance stability. To achieve a stable gradient structure on the surface coating, the drying and curing temperature is preferably within three ranges: Zone 1: 80°C - 120°C, curing time: 1-2 minutes. This stage primarily allows the water repellent to be evenly distributed throughout the filter material and evaporates excess water. The lower temperature prevents the coating from accumulating on the surface due to rapid evaporation, allowing it to fully penetrate the fibers within the material. Zone 2: 120°C - 160°C, curing time: 1-2 minutes. The surface coating begins to cure initially, and water continues to evaporate. As the temperature rises, some components in the agent undergo a chemical reaction, gradually transforming from a liquid to a solid state, allowing it to better adhere to the fiber surface. Zone 3: 160°C - 220°C, curing time: 5-10 minutes. This is the critical drying and curing stage. During this high temperature stage, the coating fully cures, forming a more stable and dense water repellent structure. The high temperature promotes the full reaction of chemical bonds in the water repellent, allowing it to tightly bond to the filter material fibers.

[0034] Various performance test methods of the filter material of the present invention are as follows, but are not limited to these test methods.

[0035] Test method for the surface adhesion ratio of dust removal filter materials: The adhesion of the fiber surface coating is analyzed by combining SEM, ultraviolet-visible spectroscopy (UV-Vis) technology, and Raman spectroscopy technology on fibers at different locations.

[0036] Dust removal filter material surface water and oil resistance test: Based on GB / T4745-2012 "Test and evaluation of water resistance of textiles - Water immersion method", the filter material's water and oil resistance rating is tested to evaluate its water and oil resistance performance.

[0037] Water repellency: Take a flat filter material at least 18 x 18 cm, dampen it, and clamp it in a fixture (at a 45° angle to the horizontal plane). With the front side facing upward, quickly and steadily pour 250 ml of water into the funnel. Continue spraying for 25-30 seconds. After stopping the spraying, remove the holder holding the sample and gently tap it once horizontally against a solid object with the front side facing downward. Then rotate 180° and tap again. Finally, evaluate the filter material based on the water repellency rating. In this case, a water repellency rating of 4 or higher is considered acceptable.

[0038] Oil repellency: Lay the test sample face-up on a smooth, horizontal absorbent pad. Starting with oil number 1, drop five small drops (approximately 0.05 ml) onto the sample. Place the drops 4 cm apart and hold the tip of the dropper 6 mm from the sample surface. Observe the drops at a 45° angle for 30 seconds ± 2 seconds. Evaluate according to the evaluation criteria and comparison chart. In this case, oil repellency of level 7 or higher is considered acceptable.

[0039] Evaluation of the surface filtration performance of dust removal filter materials: The filtration performance of the filter materials was evaluated using VDI 3926-1:2004 "Testing of cleanable filter media - Standard test for the evaluation of cleanable filter media" to determine their filtration effect and efficiency in actual dust removal applications.

[0040] The performance of the filter material was determined based on the VDI3926 standard. The size of the test sample was 150 mm in diameter and the feed dust concentration was 5.0 ± 0.5 g / m 3 , the filtration wind speed is 2m / min (air volume 1.85m 3 / h). The experimental sequence is the initial 30 times + stabilization 5000 times + the final 30 times. The method for the initial 30 times and the final 30 times is: as the running time increases, the pressure difference on both sides of the filter material will gradually increase. When the pressure difference reaches 1000Pa, the pulse air will clean the dust on the surface of the filter material, and then proceed to the next process. This process is repeated 30 times. During the experiment, the experimental time (t / s) and pressure changes are recorded, and the weight M (g) of the dust passing through the filter material is weighed at the same time. The stabilization process means that during the operation, the filter material is cleaned at intervals of 5s, the cleaning pressure is 5bar, and the number of cleaning times is 5000. The calculation formulas for the outlet dust concentration and capture efficiency are as follows:

[0041] The outlet dust concentration C = the weight of dust passing through the filter material M / (1.85×time t / 3600). The unit of outlet dust concentration C is g / m 3 ;

[0042] Collection efficiency = (1-export dust concentration C / 5) × 100%;

[0043] The pressure loss is the pressure loss automatically recorded by the equipment after the last injection of the last 30 times;

[0044] The cycle time is the total time spent on the last 30 cycles.

[0045] The present invention is further described in detail below through specific examples and comparative examples, but the present invention is not limited to these examples.

[0046] Example 1: A mixture of aramid fibers was selected as the primary filter media fiber. Opening and mixing processes were performed to produce a semi-finished needled felt with a unit weight of 600 g / m², which was then heat-set. In the surface coating preparation, a linear perfluoroalkyl compound with eight carbon atoms was added to achieve a surface solids content of 8 g, an organic fluorine-silicon-modified acrylate compound was added to achieve a surface solids content of 5 g, an ethoxylated nonionic fluorocarbon surfactant was added to achieve a surface solids content of 2.5 g, a silane coupling agent content of 2.5%, a BHT (tert-butylhydroquinone) content of 1.5%, and the remainder being water. Spray coating was performed according to the specified spraying parameters, followed by drying and setting in a drying and setting machine at 100°C in zone 1 for 1.5 minutes, 140°C in zone 2 for 1.5 minutes, and 180°C in zone 3 for 8 minutes. The filter material of the present invention was finally produced. The physical properties of the filter material are shown in Table 1.

[0047] Example 2: A mixture of aramid fibers was selected as the primary filter media fiber. Opening and mixing processes were performed to produce a semi-finished needled felt with a unit weight of 600 g / m², which was then heat-set. In the surface coating preparation, a linear perfluoroalkyl compound with eight carbon atoms was added to achieve a surface solids content of 25 g, an organic fluorine-silicon-modified acrylate compound was added to achieve a surface solids content of 5 g, an ethoxylated nonionic fluorocarbon surfactant was added to achieve a surface solids content of 2.5 g, a silane coupling agent content of 2.5%, a BHT (tert-butylhydroquinone) content of 1%, and the remainder being water. Spray coating was performed according to the specified spraying parameters, followed by drying and setting in a drying and setting machine with a first zone temperature of 100°C for 1.5 minutes, a second zone temperature of 140°C for 1.5 minutes, and a third zone temperature of 180°C for 8 minutes. The filter material of the present invention was finally produced. The physical properties of the filter material are shown in Table 1.

[0048] Example 3: A mixture of aramid fibers was selected as the primary filter media fiber. Opening and mixing processes were performed to produce a semi-finished needled felt with a unit weight of 600 g / m², which was then heat-set. In the surface coating preparation, a linear perfluoroalkyl compound with eight carbon atoms was added to achieve a surface solids content of 35 g, an organic fluorine-silicon-modified acrylate compound was added to achieve a surface solids content of 5 g, an ethoxylated nonionic fluorocarbon surfactant was added to achieve a surface solids content of 2.5 g, a silane coupling agent content of 2.5%, a BHT (tert-butylhydroquinone) content of 1.5%, and the remainder being water. Spray coating was performed according to the specified spraying parameters, followed by drying and setting in a drying and setting machine with a first zone temperature of 100°C for 1.5 minutes, a second zone temperature of 140°C for 1.5 minutes, and a third zone temperature of 180°C for 8 minutes. The filter material of the present invention was finally produced. The physical properties of the filter material are shown in Table 1.

[0049] Example 4: A mixture of aramid fibers was selected as the primary filter media fiber. Opening and mixing processes were performed to produce a semi-finished needled felt with a unit weight of 600 g / m², which was then heat-set. In the surface coating preparation, a six-carbon linear perfluoroalkyl and polyfluoroalkyl compound was added to achieve a surface solids content of 25 g, an organic fluorine-silicon-modified acrylate compound to achieve a surface solids content of 5 g, an ethoxylated nonionic fluorocarbon surfactant to achieve a surface solids content of 2.5 g, a silane coupling agent content of 2.5%, a BHT (tert-butylhydroquinone) content of 1.5%, and the remainder being water. Spray coating was performed according to the specified spraying parameters, followed by drying and setting in a drying and setting machine with a first zone temperature of 100°C for 1.5 minutes, a second zone temperature of 140°C for 1.5 minutes, and a third zone temperature of 180°C for 8 minutes. The filter material of the present invention was finally produced. The physical properties of the filter material are shown in Table 1.

[0050] Example 5: A mixture of aramid fibers was selected as the primary filter media fiber. Opening and mixing processes were performed to produce a semi-finished needled felt with a unit weight of 600 g / m², which was then heat-set. In the surface coating preparation, a linear perfluoroalkyl compound with eight carbon atoms was added to achieve a surface solids content of 25 g, an organic fluorine-silicon-modified acrylate compound was added to achieve a surface solids content of 3 g, an ethoxylated nonionic fluorocarbon surfactant was added to achieve a surface solids content of 2.5 g, a silane coupling agent content of 2.5%, a BHT (tert-butylhydroquinone) content of 1.5%, and the remainder being water. Spray coating was performed according to the specified spraying parameters, followed by drying and setting in a drying and setting machine with a first zone temperature of 100°C for 1.5 minutes, a second zone temperature of 140°C for 1.5 minutes, and a third zone temperature of 180°C for 8 minutes. The filter material of the present invention was finally produced. The physical properties of the filter material are shown in Table 1.

[0051] Example 6: A mixture of aramid fibers was selected as the primary filter media fiber. Opening and mixing processes were performed to produce a semi-finished needled felt with a unit weight of 600 g / m², which was then heat-set. In the surface coating preparation, a linear perfluoroalkyl compound with eight carbon atoms was added to achieve a surface solids content of 25 g, an organic fluorine-silicon-modified acrylate compound was added to achieve a surface solids content of 9 g, an ethoxylated nonionic fluorocarbon surfactant was added to achieve a surface solids content of 2.5 g, a silane coupling agent content of 2.5%, a BHT (tert-butylhydroquinone) content of 1.5%, and the remainder being water. Spray coating was performed according to the specified spraying parameters, followed by drying and setting in a drying and setting machine with a first zone temperature of 100°C for 1.5 minutes, a second zone temperature of 140°C for 1.5 minutes, and a third zone temperature of 180°C for 8 minutes. The filter material of the present invention was finally produced. The physical properties of the filter material are shown in Table 1.

[0052] Example 7: A mixture of aramid fibers was selected as the primary filter media fiber. Opening and mixing processes were performed to produce a semi-finished needled felt with a unit weight of 600 g / m², which was then heat-set. In the surface coating preparation, a linear perfluoroalkyl compound with eight carbon atoms was added to achieve a surface solids content of 25 g, an organic fluorine-silicon-modified acrylate compound was added to achieve a surface solids content of 15 g, an ethoxylated nonionic fluorocarbon surfactant was added to achieve a surface solids content of 2.5 g, a silane coupling agent content of 2.5%, a BHT (tert-butylhydroquinone) content of 1.5%, and the remainder being water. Spray coating was performed according to the specified spraying parameters, followed by drying and setting in a drying and setting machine with a first zone temperature of 100°C for 1.5 minutes, a second zone temperature of 140°C for 1.5 minutes, and a third zone temperature of 180°C for 8 minutes. The filter material of the present invention was finally produced. The physical properties of the filter material are shown in Table 1.

[0053] Example 8: A mixture of aramid fibers was selected as the primary filter media fiber. Opening and mixing processes were performed to produce a semi-finished needled felt with a unit weight of 600 g / m², which was then heat-set. In the surface coating preparation, a linear perfluoroalkyl compound with eight carbon atoms was added to achieve a surface solids content of 25 g, an organic fluorine-silicon-modified acrylate compound was added to achieve a surface solids content of 5 g, an ethoxylated nonionic fluorocarbon surfactant was added to achieve a surface solids content of 1.5 g, a silane coupling agent content of 2.5%, a BHT (tert-butylhydroquinone) content of 1.5%, and the remainder being water. Spray coating was performed according to the specified spraying parameters, followed by drying and setting in a drying and setting machine with a first zone temperature of 100°C for 1.5 minutes, a second zone temperature of 140°C for 1.5 minutes, and a third zone temperature of 180°C for 8 minutes. The filter material of the present invention was finally produced. The physical properties of the filter material are shown in Table 1.

[0054] Example 9: A mixture of aramid fibers was selected as the primary filter media fiber. Opening and mixing processes were performed to produce a semi-finished needled felt with a unit weight of 600 g / m², which was then heat-set. In the surface coating preparation, a linear perfluoroalkyl compound with eight carbon atoms was added to achieve a surface solids content of 25 g, an organic fluorosilicone-modified acrylate compound was added to achieve a surface solids content of 5 g, an ethoxylated nonionic fluorocarbon surfactant was added to achieve a surface solids content of 2 g, a silane coupling agent content of 2.5%, a BHT (tert-butylhydroquinone) content of 1.5%, and the remainder being water. Spray coating was performed according to the specified spraying parameters, followed by drying and setting in a drying and setting machine at 100°C in zone 1 for 1.5 minutes, 140°C in zone 2 for 1.5 minutes, and 180°C in zone 3 for 8 minutes. The filter material of the present invention was finally produced. The physical properties of the filter material are shown in Table 1.

[0055] Example 10: A mixture of aramid fibers was selected as the primary filter media fiber. Opening and mixing processes were performed to produce a semi-finished needled felt with a unit weight of 600 g / m², which was then heat-set. In the surface coating preparation, a linear perfluoroalkyl compound with eight carbon atoms was added to achieve a surface solids content of 25 g, an organic fluorosilicone-modified acrylate compound to achieve a surface solids content of 5 g, an ethoxylated nonionic fluorocarbon surfactant to achieve a surface solids content of 5 g, a silane coupling agent content of 2.5%, a BHT (tert-butylhydroquinone) content of 1.5%, and the remainder being water. Spray coating was performed according to the specified spraying parameters, followed by drying and setting in a drying and setting machine with a first zone temperature of 100°C for 1.5 minutes, a second zone temperature of 140°C for 1.5 minutes, and a third zone temperature of 180°C for 8 minutes. The filter material of the present invention was finally produced. The physical properties of the filter material are shown in Table 1.

[0056] Example 11: A mixture of aramid fibers was selected as the primary filter media fiber. Opening and mixing processes were performed to produce a semi-finished needled felt with a unit weight of 600 g / m², which was then heat-set. In the surface coating preparation, a linear perfluoroalkyl compound with eight carbon atoms was added to achieve a surface solids content of 25 g, an organic fluorine-silicon-modified acrylate compound was added to achieve a surface solids content of 5 g, an ethoxylated nonionic fluorocarbon surfactant was added to achieve a surface solids content of 2.5 g, a silane coupling agent content of 1.5%, a BHT (tert-butylhydroquinone) content of 1.5%, and the remainder being water. Spray coating was performed according to the specified spraying parameters, followed by drying and setting in a drying and setting machine with a first zone temperature of 100°C for 1.5 minutes, a second zone temperature of 140°C for 1.5 minutes, and a third zone temperature of 180°C for 8 minutes. The filter material of the present invention was finally produced. The physical properties of the filter material are shown in Table 1.

[0057] Example 12: A mixture of aramid fibers was selected as the primary filter media fiber. Opening and mixing processes were performed to produce a semi-finished needled felt with a unit weight of 600 g / m², which was then heat-set. In the surface coating preparation, a linear perfluoroalkyl compound with eight carbon atoms was added to achieve a surface solids content of 25 g, an organic fluorosilicone-modified acrylate compound was added to achieve a surface solids content of 5 g, an ethoxylated nonionic fluorocarbon surfactant was added to achieve a surface solids content of 2.5 g, a silane coupling agent content of 2%, a BHT (tert-butylhydroquinone) content of 1.5%, and the remainder being water. Spray coating was performed according to the specified spraying parameters, followed by drying and setting in a drying and setting machine with a first zone temperature of 100°C for 1.5 minutes, a second zone temperature of 140°C for 1.5 minutes, and a third zone temperature of 180°C for 8 minutes. The filter material of the present invention was finally produced. The physical properties of the filter material are shown in Table 1.

[0058] Example 13: A mixture of aramid fibers was selected as the primary filter media fiber. Opening and mixing processes were performed to produce a semi-finished needled felt with a unit weight of 600 g / m², which was then heat-set. In the surface coating preparation, a linear perfluoroalkyl compound with eight carbon atoms was added to achieve a surface solids content of 25 g, an organic fluorosilicone-modified acrylate compound was added to achieve a surface solids content of 5 g, an ethoxylated nonionic fluorocarbon surfactant was added to achieve a surface solids content of 2.5 g, a silane coupling agent content of 5%, a BHT (tert-butylhydroquinone) content of 1.5%, and the remainder being water. Spray coating was performed according to the specified spraying parameters, followed by drying and setting in a drying and setting machine with a first zone temperature of 100°C for 1.5 minutes, a second zone temperature of 140°C for 1.5 minutes, and a third zone temperature of 180°C for 8 minutes. The filter material of the present invention was finally produced. The physical properties of the filter material are shown in Table 1.

[0059] Example 14: A mixture of aramid fibers was selected as the primary filter media fiber. Opening and mixing processes were performed to produce a semi-finished needled felt with a unit weight of 600 g / m², which was then heat-set. In the surface coating preparation, a linear perfluoroalkyl compound with eight carbon atoms was added to achieve a surface solids content of 25 g, an organic fluorosilicone-modified acrylate compound to achieve a surface solids content of 5 g, an ethoxylated nonionic fluorocarbon surfactant to achieve a surface solids content of 2.5 g, a silane coupling agent content of 2.5%, a BHA (butylated hydroxyanisole) content of 1.5%, and the remainder being water. Spray coating was performed according to the specified spraying parameters, followed by drying and setting in a drying and setting machine with a first zone temperature of 100°C for 1.5 minutes, a second zone temperature of 140°C for 1.5 minutes, and a third zone temperature of 180°C for 8 minutes. The filter material of the present invention was finally produced. The physical properties of the filter material are shown in Table 1.

[0060] Example 15: A mixture of aramid fibers was selected as the primary filter media fiber. Opening and mixing processes were performed to produce a semi-finished needled felt with a unit weight of 600 g / m², which was then heat-set. In the surface coating preparation, a linear perfluoroalkyl compound with eight carbon atoms was added to achieve a surface solids content of 8 g, an organic fluorine-silicon-modified acrylate compound was added to achieve a surface solids content of 5 g, an ethoxylated nonionic fluorocarbon surfactant was added to achieve a surface solids content of 2.5 g, a silane coupling agent content of 2.5%, a BHT (tert-butylhydroquinone) content of 1%, and the remainder being water. Spray coating was performed according to the specified spraying parameters, followed by drying and setting in a drying and setting machine with a first zone temperature of 100°C for 1.5 minutes, a second zone temperature of 140°C for 1.5 minutes, and a third zone temperature of 180°C for 8 minutes. The filter material of the present invention was finally produced. The physical properties of the filter material are shown in Table 1.

[0061] Example 16: A mixture of aramid fibers was selected as the primary filter media fiber. Opening and mixing processes were performed to produce a semi-finished needled felt with a unit weight of 600 g / m², which was then heat-set. In the surface coating preparation, a linear perfluoroalkyl compound with eight carbon atoms was added to achieve a surface solids content of 8 g, an organic fluorine-silicon-modified acrylate compound was added to achieve a surface solids content of 5 g, an ethoxylated nonionic fluorocarbon surfactant was added to achieve a surface solids content of 2.5 g, a silane coupling agent content of 2.5%, a BHT (tert-butylhydroquinone) content of 1%, and the remainder being water. Spray coating was performed according to the specified spraying parameters, followed by drying and setting in a drying and setting machine with a first zone temperature of 100°C for 1.5 minutes, a second zone temperature of 140°C for 1.5 minutes, and a third zone temperature of 180°C for 8 minutes. The filter material of the present invention was finally produced. The physical properties of the filter material are shown in Table 1.

[0062] Comparative Example 1: A mixture of aramid fibers was selected as the primary filter media fiber. Opening and mixing processes were performed to produce a semi-finished needled felt with a unit weight of 600 g / m², which was then heat-set. In the surface coating preparation, a linear perfluoroalkyl compound with eight carbon atoms was added to achieve a surface solids content of 1g, an organic fluorosilicone-modified acrylate compound to achieve a surface solids content of 5g, an ethoxylated nonionic fluorocarbon surfactant to achieve a surface solids content of 2.5g, a silane coupling agent content of 2.5%, a BHT (tert-butylhydroquinone) content of 1.5%, and the remainder being water. Spray coating was performed according to the specified spraying parameters, followed by drying and setting in a drying and setting machine at 100°C in zone 1 for 1.5 minutes, 140°C in zone 2 for 1.5 minutes, and 180°C in zone 3 for 8 minutes. The filter material of the present invention was finally produced. The physical properties of the filter material are shown in Table 2.

[0063] Comparative Example 2: A mixture of aramid fibers was selected as the primary filter media fiber. Opening and mixing processes were performed to produce a semi-finished needled felt with a unit weight of 600 g / m², which was then heat-set. In the surface coating preparation, a linear perfluoroalkyl compound with eight carbon atoms was added to achieve a surface solids content of 3g, an organic fluorosilicone-modified acrylate compound to achieve a surface solids content of 5g, an ethoxylated nonionic fluorocarbon surfactant to achieve a surface solids content of 2.5g, a silane coupling agent content of 2.5%, a BHT (tert-butylhydroquinone) content of 1.5%, and the remainder being water. Spray coating was performed according to the specified spraying parameters, followed by drying and setting in a drying and setting machine at 100°C in zone 1 for 1.5 minutes, 140°C in zone 2 for 1.5 minutes, and 180°C in zone 3 for 8 minutes. The filter material of the present invention was finally produced. The physical properties of the filter material are shown in Table 2.

[0064] Comparative Example 3: A mixture of aramid fibers was selected as the primary filter media fiber. Opening and mixing processes were performed to produce a semi-finished needled felt with a unit weight of 600 g / m², which was then heat-set. During the surface coating preparation, a linear perfluoroalkyl compound with eight carbon atoms was added to achieve a surface solids content of 45 g, an organic fluorine-silicon-modified acrylate compound was added to achieve a surface solids content of 0.5 g, an ethoxylated nonionic fluorocarbon surfactant was added to achieve a surface solids content of 2.5 g, a silane coupling agent content of 2.5%, a BHT (tert-butylhydroquinone) content of 1.5%, and the remainder being water. Spray coating was performed according to the specified spraying parameters, followed by drying and setting in a drying and setting machine at 100°C in zone 1 for 1.5 minutes, 140°C in zone 2 for 1.5 minutes, and 180°C in zone 3 for 8 minutes. The filter material of the present invention was finally produced. The physical properties of the filter material are shown in Table 2.

[0065] Comparative Example 4: A mixture of aramid fibers was selected as the primary filter media fiber. Opening and mixing processes were performed to produce a semi-finished needled felt with a unit weight of 600 g / m², which was then heat-set. In the surface coating preparation, a linear perfluoroalkyl compound with eight carbon atoms was added to achieve a surface solids content of 60 g, an organic fluorosilicone-modified acrylate compound was added to achieve a surface solids content of 15 g, an ethoxylated nonionic fluorocarbon surfactant was added to achieve a surface solids content of 2.5 g, a silane coupling agent content of 2.5%, a BHT (tert-butylhydroquinone) content of 1.5%, and the remainder being water. Spray coating was performed according to the specified spraying parameters, followed by drying and setting in a drying and setting machine at 100°C in zone 1 for 1.5 minutes, 140°C in zone 2 for 1.5 minutes, and 180°C in zone 3 for 8 minutes. The filter material of the present invention was finally produced. The physical properties of the filter material are shown in Table 2.

[0066] Comparative Example 5: A mixture of aramid fibers was selected as the primary filter media fiber. Opening and mixing processes were performed to produce a semi-finished needled felt with a unit weight of 600 g / m², which was then heat-set. In the surface coating preparation, a linear perfluoroalkyl compound with eight carbon atoms was added to achieve a surface solids content of 8 g, an organic fluorosilicone-modified acrylate compound was added to achieve a surface solids content of 0.5 g, an ethoxylated nonionic fluorocarbon surfactant was added to achieve a surface solids content of 2.5 g, a silane coupling agent content of 2.5%, a BHT (tert-butylhydroquinone) content of 1.5%, and the remainder being water. Spray coating was performed according to the specified spraying parameters, followed by drying and setting in a drying and setting machine at 100°C in zone 1 for 1.5 minutes, 140°C in zone 2 for 1.5 minutes, and 180°C in zone 3 for 8 minutes. The filter material of the present invention was finally produced. The physical properties of the filter material are shown in Table 2.

[0067] Comparative Example 6: A mixture of aramid fibers was selected as the primary filter media fiber. Opening and mixing processes were performed to produce a semi-finished needled felt with a unit weight of 600 g / m², which was then heat-set. In the surface coating preparation, a linear perfluoroalkyl compound with eight carbon atoms was added to achieve a surface solids content of 25 g, an organic fluorosilicone-modified acrylate compound was added to achieve a surface solids content of 20 g, an ethoxylated nonionic fluorocarbon surfactant was added to achieve a surface solids content of 2.5 g, a silane coupling agent content of 2.5%, a BHT (tert-butylhydroquinone) content of 1.5%, and the remainder being water. Spray coating was performed according to the specified spraying parameters, followed by drying and setting in a drying and setting machine at 100°C in zone 1 for 1.5 minutes, 140°C in zone 2 for 1.5 minutes, and 180°C in zone 3 for 8 minutes. The filter material of the present invention was finally produced. The physical properties of the filter material are shown in Table 2.

[0068] Comparative Example 7: A mixture of aramid fibers was selected as the primary filter media fiber. Opening and mixing processes were performed to produce a semi-finished needled felt with a unit weight of 600 g / m², which was then heat-set. In the surface coating preparation, a linear perfluoroalkyl compound with eight carbon atoms was added to achieve a surface solids content of 25 g, an organic fluorosilicone-modified acrylate compound was added to achieve a surface solids content of 5 g, an ethoxylated nonionic fluorocarbon surfactant was added to achieve a surface solids content of 10 g, a silane coupling agent content of 2.5%, a BHT (tert-butylhydroquinone) content of 1.5%, and the remainder being water. Spray coating was performed according to the specified spraying parameters, followed by drying and setting in a drying and setting machine at 100°C in zone 1 for 1.5 minutes, 140°C in zone 2 for 1.5 minutes, and 180°C in zone 3 for 8 minutes. The filter material of the present invention was finally produced. The physical properties of the filter material are shown in Table 2.

[0069] Comparative Example 8: A mixture of aramid fibers was selected as the primary filter media fiber. Opening and mixing processes were performed to produce a semi-finished needled felt with a unit weight of 600 g / m², which was then heat-set. In the surface coating preparation, a linear perfluoroalkyl compound with eight carbon atoms was added to achieve a surface solids content of 25 g, an organic fluorosilicone-modified acrylate compound was added to achieve a surface solids content of 5 g, an ethoxylated nonionic fluorocarbon surfactant was added to achieve a surface solids content of 2.5 g, a silane coupling agent content of 10%, a BHT (tert-butylhydroquinone) content of 1.5%, and the remainder being water. Spray coating was performed according to the specified spraying parameters, followed by drying and setting in a drying and setting machine at 100°C in zone 1 for 1.5 minutes, 140°C in zone 2 for 1.5 minutes, and 180°C in zone 3 for 8 minutes. The filter material of the present invention was finally produced. The physical properties of the filter material are shown in Table 2.

[0070] Comparative Example 9: A mixture of aramid fibers was selected as the primary filter media fiber. Opening and mixing processes were performed to produce a semi-finished needled felt with a unit weight of 600 g / m², which was then heat-set. In the surface coating preparation, a linear perfluoroalkyl compound with eight carbon atoms was added to achieve a surface solids content of 25 g, an organic fluorosilicone-modified acrylate compound was added to achieve a surface solids content of 5 g, an ethoxylated nonionic fluorocarbon surfactant was added to achieve a surface solids content of 2.5 g, a silane coupling agent content of 2.5%, a BHT (tert-butylhydroquinone) content of 10%, and the remainder being water. Spray coating was performed according to the specified spraying parameters, followed by drying and setting in a drying and setting machine at 100°C in zone 1 for 1.5 minutes, 140°C in zone 2 for 1.5 minutes, and 180°C in zone 3 for 8 minutes. The filter material of the present invention was finally produced. The physical properties of the filter material are shown in Table 2.

[0071] Comparative Example 10: A mixture of aramid fibers was selected as the primary filter material. Opening and mixing processes were performed to produce a semi-finished needle-punched felt with a unit weight of 600 g / m². This was then heat-set. Zone 1 was treated at 100°C for 1.5 minutes, zone 2 at 140°C for 1.5 minutes, and zone 3 at 180°C for 8 minutes. This resulted in the filter material of the present invention. See Table 2 for the physical properties of the filter material.

[0072] Table 1 Physical properties of Examples 1-16

[0073]

[0074] Table 2 Physical properties of Comparative Examples 1-10

[0075]

[0076] According to the above table, we can draw the following conclusions:

[0077] (1) The data from Examples 1-6 fully demonstrate that, within the specified range, the filter material achieved a water resistance of Grade 4 and an oil resistance of Grade 7 or higher, meeting the requirements of the present invention. After high-temperature treatment at 240°C for 24 hours, the filter material still maintained a water resistance of Grade 3-4 and an oil resistance of Grade 6 or higher.

[0078] (2) It can be seen from Examples 1, 2, and 3 that, under the same conditions, the ratio of perfluoroalkyl and polyfluoroalkyl compounds with straight carbon chains is within the preferred range. The higher the adhesion ratio, the higher the adhesion ratio of the gradient distribution of surface coatings with different thicknesses, and the higher the water and oil repellency level.

[0079] (3) As can be seen from Examples 2 and 4, the number of carbon atoms in the straight-chain perfluoroalkyl and polyfluoroalkyl compounds is within the preferred range. When the number of carbon atoms is 8, the water and oil repellency is higher.

[0080] (4) As can be seen from Examples 2, 5, 6, and 7, the attachment weight of the organic fluorine-silicon-modified acrylate compound is within the preferred range. The higher the attachment weight, the lower the VDI outlet concentration and the longer the cycle time of the resulting filter material. When the addition ratio is too high, the dust removal ability deteriorates, the dust outlet concentration increases, the cycle time decreases, and the VDI performance index is poor.

[0081] (5) It can be seen from Examples 2, 8, 9, and 10 that, within the specified range, when different proportions of ethoxylated nonionic fluorocarbon surfactants are added, the performance indicators of the filter materials obtained meet the requirements of the present invention. When the addition ratio is too high, the dust removal ability deteriorates, the dust outlet concentration increases, the cycle time decreases, and the VDI performance index is poor.

[0082] (6) It can be seen from Examples 2, 11, 12, and 13 that within the specified range, when the silane coupling agent is added in different proportions, the performance indicators of the filter material obtained are all good. When the addition ratio is too high, the dust removal ability deteriorates, the dust outlet concentration increases, the cycle time decreases, and the VDI performance index is poor.

[0083] (7) It can be seen from Examples 2 and 14 that, within the specified range, when BHA (butylated hydroxyanisole) and BHT (tert-butylhydroquinone) are selected, the performance indicators of the filter material obtained are all good.

[0084] (8) It can be seen from Examples 2, 15, and 16 that within the specified range, when the stabilizer is added in different proportions, the performance indicators of the filter material obtained are all good. When the addition ratio is too high, the dust removal ability deteriorates, the dust outlet concentration increases, the cycle time decreases, and the VDI performance index is poor.

[0085] (9) It can be seen from Example 2 and Comparative Examples 1 and 2 that the attached gram weight of the straight-chain carbon atom perfluoro and polyfluoroalkyl compounds is too low. Although the waterproof and oil-proof performance meets the requirements of the present invention, the dust removal ability becomes poor, the dust outlet concentration increases, and the VDI performance index is poor.

[0086] (10) It can be seen from Example 2 and Comparative Examples 1 and 2 that the attachment weight of the straight-chain perfluoroalkyl and polyfluoroalkyl compounds of carbon atoms is too low, the attachment ratio of the gradient distribution of the surface coating at different thicknesses does not meet the requirements, the water and oil repellent ability is affected, the dust removal ability becomes worse, the dust outlet concentration increases, the cycle time decreases, and the VDI performance index is poor.

[0087] (11) It can be seen from Example 2 and Comparative Examples 3 and 4 that the weight of the organic fluorosilicone modified acrylate compound is too high, the adhesion ratio of the surface coating with different thickness gradient distribution is too high in some thickness ranges, the dust removal ability becomes poor, the dust outlet concentration increases, the cycle time decreases, and the VDI performance index is poor.

[0088] (12) It can be seen from Example 1 and Comparative Example 5 that the adhesion weight of the organic fluorosilicone modified acrylate compound is too low, the adhesion ratio of the surface coating with different thickness gradient distribution does not meet the requirements in some thickness ranges, the ability of the water and oil repellent is affected, the dust removal ability becomes worse, the dust outlet concentration increases, and the VDI performance index is poor.

[0089] (13) It can be seen from Example 2 and Comparative Example 6 that if the adhesion weight of the organic fluorosilicone modified acrylate compound is too high, the adhesion ratio of the surface coating with different thickness gradient distribution will not meet the requirements in some thickness ranges, the dust removal ability will deteriorate, the dust outlet concentration will increase, and the VDI performance index will be poor.

[0090] (14) It can be seen from Example 2 and Comparative Examples 6, 7, 8 and 9 that if the ethoxylated nonionic fluorocarbon surfactant, silane coupling agent and stabilizer have too high an attachment weight, the attachment ratio of the surface coating with different thickness gradient distribution will not meet the requirements in some thickness ranges, the water and oil repellent capability will be affected, the dust removal capability will be deteriorated, the dust outlet concentration will increase, and the VDI performance index will be poor.

[0091] (15) It can be seen from Example 4 and Comparative Example 10 that the dust removal filter material with anti-condensation and self-cleaning properties of the present invention has better water and oil repellency after treatment at 240°C for 24 hours than the filter material with the same filter material body and only perfluoro and polyfluoroalkyl compounds with straight carbon atoms added thereto. The VDI performance outlet concentration of the filter material of the present invention is 0.2-0.4 mg / m 3 , the outlet concentration is also slightly reduced, and the VDI performance index is better.

[0092] The above examples demonstrate that the anti-condensation and self-cleaning dust removal filter material and its preparation method of the present invention can effectively improve the performance of the filter material under complex working conditions, possessing excellent comprehensive properties such as anti-condensation, self-cleaning, waterproof and oil-proofing, and filtration, and have broad application prospects in the field of industrial dust removal. The material concepts and methods of the present invention have a wide range of applications, not limited to industrial dust removal, and can be expanded to other fields such as civilian clothing, building protection, and agricultural production in the future. It has significant advantages and feasibility for expansion and extension into multiple fields and deep integration of applications.

[0093] The above embodiments of the present invention are merely examples to clearly illustrate the present invention, but are not intended to limit the scope of protection of the present invention. All equivalent technical solutions also fall within the scope of the present invention. The scope of patent protection of the present invention should be defined by the claims.

Claims

1. Dust removal filter material with anti-condensation and self-cleaning properties, characterized by: The filter material consists of a filter body and a surface treatment layer; the filter body is a filter felt prepared by a needle punching process; The surface treatment layer is evenly covered on the surface of the fiber layer, and its main components are perfluoro and polyfluoroalkyl compounds containing linear carbon atoms, and further contain organic fluorine-silicon modified acrylate compounds and ethoxylated nonionic fluorocarbon surfactants; the solid adhesion amount of the perfluoro and polyfluoroalkyl compounds containing linear carbon atoms on the filter material is 5 to 40 g / m²; the solid adhesion amount of the organic fluorine-silicon modified acrylate compounds is 2 to 10 g / m²; and the solid adhesion amount of the ethoxylated nonionic fluorocarbon surfactant is 1 to 3 g / m²; The surface treatment component uniformly covers the fiber surface at a thickness of 0-50 microns from the surface, and covers at least 90% of the area of ​​the fiber surface; at a thickness of 50-100 microns below the surface, the surface treatment component covers at least 75% of the area of ​​the fiber surface; at a thickness of less than 200 microns below the surface, the surface treatment component covers less than or equal to 20% of the area of ​​the fiber surface.

2. The dust removal filter material with anti-condensation and self-cleaning properties according to claim 1, characterized in that: The carbon atom linear perfluoroalkyl and polyfluoroalkyl compounds in the surface treatment layer are in the form of linear chains of six or more carbon atoms.

3. The dust removal filter material with anti-condensation and self-cleaning properties according to claim 1, characterized in that: The fibers constituting the main body of the filter material are a mixture of one or more of PPS fibers, aramid fibers, glass fibers, basalt fibers, polyimide, and polytetrafluoroethylene.

4. A method for preparing the dust removal filter material with anti-condensation and self-cleaning properties according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step 1: Preparation of filter material: Select fibers and base fabrics, open, mix, finely open, card, lay, add base fabrics, and needle punch the short fibers to make semi-finished needle-punched felt. The unit weight is controlled at 400-900 g / m2. The prepared filter felt is then subjected to post-processing such as singeing, calendering, and heat setting as needed. Step 2: Prepare the surface coating treatment liquid. The liquid is configured according to the mass of solid adhesion on the filter media surface: 5-40g / m² of straight-chain perfluoroalkyl and polyfluoroalkyl compounds, 2-10g / m² of organic fluorine-silicon modified acrylate compounds, 1-3g / m² of ethoxylated non-ionic fluorocarbon surfactants. A crosslinking agent and a stabilizer are also added to the prepared treatment liquid, and the rest is water. Step 3: Surface coating spraying, evenly apply it on the surface of the high-temperature resistant fiber layer by spraying. The spraying distance during the spraying process is between 15cm-30cm, and the spraying inclination angle is less than or equal to 45 degrees before and after the vertical direction of the filter material. The relative humidity is between 40% and 70%, and the ambient temperature is controlled between 10℃ and 35℃. Step 4: Dry and shape the prepared filter material to improve its performance stability; the drying and shaping temperature is in three temperature ranges: Zone 1: 80℃~120℃, and the treatment time is 1~2 minutes; Zone 2: 120℃~160℃, treatment time is 1~2 minutes; Zone 3: 160℃~220℃, treatment time is 5~10 minutes.

5. The method for preparing the dust removal filter material with anti-condensation and self-cleaning properties according to claim 4, characterized in that: The crosslinking agent in step 2 is a silane coupling agent, and the added content is 1-3%; the stabilizer is one of butylated hydroxyanisole (BHA) or BHT (tert-butylhydroquinone), and the added content is 0.5-2%.

6. The dust removal filter material with anti-condensation and self-cleaning properties according to claim 1, characterized in that: The waterproof and oil-proof grades of the filter material were tested based on GB / T4745-2012. The water-repellent grade of the filter material reached above grade 4, and the oil-proof grade reached above grade 7.

7. The dust removal filter material with anti-condensation and self-cleaning properties according to claim 1, characterized in that: The filtration performance of the filter material was evaluated by testing using VDI3926-1:2004, and the dust removal rate was above 99.99%.

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