Composite high-temperature-resistant filter cloth and preparation method thereof

Abstract

The application discloses a kind of composite high-temperature-resistant filter cloth and preparation method thereof, it is related to filter cloth technical field, and its technical key points include base cloth layer and coating on the surface of base cloth layer, the base cloth layer is by following weight parts of fiber composition: basalt fiber 30-50 parts, aramid fiber 20-40 parts, polyphenylene sulfide fiber 10-30 parts;The coating is by following weight parts of component composition: organic silicon modified acrylic resin 40 parts, nanometer titanium dioxide 10 parts, hydrophilic nanometer silicon dioxide 10 parts, coupling agent 3 parts, curing agent 5 parts, technical effect, the reasonable matching of base cloth layer fiber and the stable structure formed after coating optimization preparation process, so that it can withstand higher temperature, can satisfy high-temperature working condition demand, effectively expand the application range.Filter efficiency, base cloth layer fiber combination and nanometer titanium dioxide and hydrophilic nanometer silicon dioxide in coating synergistic effect in good dispersion state, dust interception, adsorption and capture effect are excellent.

Description

Technical Field

[0001] This invention relates to the field of filter cloth technology, specifically to a composite high-temperature resistant filter cloth and its preparation method. Background Technology

[0002] As a key material widely used in many fields, the development of filter cloth is closely linked to the needs of modern industry and environmental protection. It mainly separates larger impurities from the mixture through physical barrier.

[0003] In industrial production processes, such as steel, cement, and chemical industries, large amounts of dust-laden, high-temperature gases are generated. Traditional filter cloths often suffer from clogging when faced with high-humidity, sticky dust. This is because dust particles easily adhere to the filter cloth surface and are difficult to remove. As usage time increases, filtration resistance rises continuously, severely affecting filtration efficiency and the normal operation of equipment. Furthermore, for applications in high-temperature environments, the high-temperature resistance of ordinary filter cloths is insufficient to meet the requirements of long-term stable operation. Therefore, developing a filter cloth that is both high-temperature resistant and possesses good self-cleaning capabilities is of great significance. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a composite high-temperature resistant filter cloth and its preparation method. Through a special fiber combination and improved coating technology, the filter cloth possesses excellent high-temperature resistance and self-cleaning ability.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a composite high-temperature resistant filter cloth and its preparation method, comprising a base cloth layer and a coating applied to the surface of the base cloth layer, wherein the base cloth layer is composed of the following fibers in parts by weight: 30-50 parts basalt fiber, 20-40 parts aramid fiber, and 10-30 parts polyphenylene sulfide fiber; the coating is composed of the following components in parts by weight: 40 parts organosilicon modified acrylic resin, 10 parts nano titanium dioxide, 10 parts hydrophilic nano silica, 3 parts coupling agent, and 5 parts curing agent.

[0006] Preferably, the preparation method of the organosilicon modified acrylic resin is as follows: the acrylic resin and organosilicon monomer are mixed in a mass ratio of 3:1-5:1, an initiator is added, and the mixture is reacted at 70-90°C for 3-5 hours. The amount of initiator is 0.5%-1.5% of the total mass of the acrylic resin and organosilicon monomer.

[0007] Preferably, the coupling agent is a silane coupling agent KH-550.

[0008] Preferably, the curing agent is an amino resin curing agent.

[0009] Preferably, the nano-titanium dioxide has a particle size of 20-50 nm, and the hydrophilic nano-silica has a particle size of 10-30 nm.

[0010] Preferably, the preparation method of the base fabric layer includes the following steps: opening and carding basalt fiber, aramid fiber and polyphenylene sulfide fiber respectively, then blending the carded fibers to form a blended yarn, and then weaving the blended yarn to form the base fabric layer, wherein the weaving method is plain weave or twill weave.

[0011] Preferably, the coating is prepared using the following steps: Step 1: Pretreatment: Heat-treat the nano-titanium dioxide at 300-400℃ for 1-2 hours to remove surface impurities and enhance its photocatalytic activity. Cool the heat-treated nano-titanium dioxide to room temperature before use. Hydrophilic nano-silica was treated in a vacuum environment at 80-100℃ for 30-60 minutes to further improve its hydrophilicity and dispersibility. The treated hydrophilic nano-silica was then put into use. Step 2, Mixing and Dispersion: Add the silicone-modified acrylic resin to a high-speed disperser and pre-disperse it for 10-15 minutes at 40-50℃ and a speed of 1500-2000 r / min. Then, the pretreated nano-titanium dioxide, hydrophilic nano-silica, and coupling agent are slowly added to the disperser, and stirring is continued for 1-2 hours to ensure that all components are fully mixed and homogeneous, thus obtaining a preliminary coating mixture. During this process, the disperser speed is gradually increased to 2500-3000 r / min to ensure good dispersion of the nanoparticles; Step 3, Ultrasonic treatment: Transfer the preliminary coating mixture to an ultrasonic device and ultrasonically treat it at an ultrasonic frequency of 40-60kHz for 30-60 minutes to further break up the agglomeration of nanoparticles and make the coating system more uniform and stable. Step 4: Adding and stirring the curing agent: Transfer the ultrasonically treated coating mixture back to the mixing container, add the curing agent at 30-40℃, and stir at 800-1000r / min for 45-60 minutes to ensure that the curing agent is evenly dispersed in the coating system; Step 5, Vacuum Degassing: Place the coating mixture containing the curing agent in a vacuum environment, maintaining the vacuum level at -0.08MPa to -0.1MPa, and degas for 10-20 minutes to remove air bubbles from the coating and prevent defects such as pinholes from appearing in the coating.

[0012] Preferably, the preparation steps of the high-temperature resistant filter cloth coating are as follows: A1. Coating application: The base fabric layer is immersed in the degassed coating mixture for 3-5 minutes, and then rolled with rollers to control the coating thickness to 10-30μm; A2. Curing of the coating: The coated base fabric layer is then pre-cured at 80-100℃ for 2-3 minutes, and then cured at 120-150℃ for 3-5 minutes to fully cure the coating and obtain the composite filter cloth.

[0013] Compared with existing technologies, this invention provides a composite high-temperature resistant filter cloth and its preparation method, which has the following beneficial effects: Regarding high-temperature resistance, the rational ratio of the base fabric fibers and the optimized preparation process of the coating form a stable structure, enabling it to withstand higher temperatures and meet the requirements of high-temperature operating conditions, effectively expanding its application range. In terms of filtration efficiency, the synergistic effect of the base fabric fiber combination and the nano-titanium dioxide and hydrophilic nano-silica in the coating, under good dispersion, results in excellent dust interception, adsorption, and capture effects, effectively purifying dust-laden gases and ensuring a clean production environment. Regarding self-cleaning ability, the hydrophilic nano-silica treatment and uniform coating preparation process allow dust to combine with water and slide off smoothly, significantly improving self-cleaning ability caused by process defects, reducing cleaning and maintenance frequency, lowering operating costs, and extending service life. The coating and the base fabric have good adhesion, thanks to the thorough treatment of each component and reasonable process during preparation. This ensures strong chemical bonding and physical adsorption between the two, making the filter cloth structure more stable. It can maintain stable performance even under long-term use and complex working conditions, providing a high-performance and high-reliability filter material solution for the industrial filtration field. Attached Figure Description

[0014] Figure 1 A line graph showing the high-temperature resistance performance test results of a composite high-temperature resistant filter cloth; Figure 2 This is a line graph showing the bonding strength test between the coating and the base fabric of a composite high-temperature resistant filter cloth. Detailed Implementation

[0015] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0016] Detailed experimental testing steps in this invention: Sample preparation: Prepare high-temperature resistant filter cloth samples, ensuring that the size, shape, etc. of each sample meet the test requirements.

[0017] Filtration efficiency test: Install the sample in the filtration efficiency test device, ensuring a good seal and no gas leakage.

[0018] Turn on the flue gas generator to produce simulated flue gas containing a certain concentration of solid particles, and control parameters such as flue gas temperature and flow rate to make them similar to actual working conditions. For example, the temperature is set to 200℃ and the flow rate is set to 1m / min.

[0019] The simulated flue gas was passed through a filter cloth sample. After a certain period of filtration, the permeable particles were collected downstream of the filter cloth using a particulate matter collector.

[0020] The mass of collected particles was accurately weighed using a balance. The filtration efficiency of each filter cloth sample was calculated using the formula: filtration efficiency (%) = (1 - total mass of particles at the end of the test / initial total mass of particles) × 100%.

[0021] Self-cleaning ability test: Install the filter cloth sample in the self-cleaning test device and measure its initial resistance in a clean state.

[0022] A simulated dust-laden airflow containing sticky dust is introduced and maintained for a period of time to allow the dust to adhere evenly to the surface of the filter cloth until the resistance rises to a certain value.

[0023] Stop the flow of dust-laden air and observe and record the time it takes for the filter cloth to recover to its initial resistance under natural conditions. This will be used as an evaluation index of self-cleaning ability.

[0024] Temperature resistance test: Place the filter cloth sample in a high-temperature oven and raise the temperature at a certain rate (e.g., 5℃ / min).

[0025] At regular temperature intervals (e.g., 50°C), samples are removed for visual inspection, dimensional measurement, and mechanical property testing. The samples are observed for deformation, embrittlement, or breakage until they are damaged or reach the set maximum test temperature. The highest temperature at which the sample can operate normally is recorded as the test result for its temperature resistance.

[0026] Operating resistance test: The filter cloth sample is installed in the resistance test device, and clean air at a certain temperature and flow rate is introduced. The resistance at this time is measured as the initial operating resistance.

[0027] Keeping the air temperature and flow rate constant, continuously introduce air for a period of time, recording the resistance value at regular intervals until the resistance stabilizes. Observe and record the operating resistance after stabilization to evaluate the resistance characteristics of the filter cloth during actual operation.

[0028] Relevant national or industry standards for the experiment: GB / T 6719-2009 "Technical Requirements for Bag Filters": This standard specifies the basic technical requirements for bag filters, including performance indicators, structural design, manufacturing process, installation and commissioning, operation and maintenance requirements. When testing composite high-temperature resistant filter cloth, the test methods and requirements for performance indicators such as filtration efficiency and operating resistance can be referred to to ensure the accuracy and comparability of the test results.

[0029] HJ / T 324-2006 "Technical Requirements for Bag Filter Media for Environmental Protection Products": This standard specifies the technical requirements for bag filter media, covering the material, performance, appearance quality, and testing methods. When testing composite high-temperature resistant filter cloth, the relevant provisions of this standard regarding filter media performance testing should be followed, such as the test methods and judgment criteria for indicators like temperature resistance, tensile strength, and air permeability, to ensure that the test results meet the requirements for environmentally friendly products.

[0030] FZ / T 64055-2015 "Filter Media for Bag Filters": This industry standard specifies the terms and definitions, product classification, technical requirements, test methods, inspection rules, marking, packaging, transportation, and storage of filter media for bag filters. In experimental testing, this standard can be used to comprehensively test and evaluate the various properties of composite high-temperature resistant filter cloths to ensure they meet the quality requirements for filter media used in bag filters.

[0031] The names and models of the instruments used in the experiment are as follows: Filtration efficiency test: High-temperature filter bag fixing device: self-made, designed and manufactured according to the size and shape of the test sample to ensure that the filter bag can be firmly fixed without affecting the passage of flue gas.

[0032] Flue gas generator: 30L type, which can generate stable simulated flue gas and accurately control parameters such as flue gas temperature, flow rate and particulate matter concentration to meet the testing needs under different working conditions.

[0033] Gas analyzer: GA-2000 model, which can monitor the concentration changes of solid particulate matter in flue gas in real time, with high measurement accuracy, and can provide accurate data support for the calculation of filtration efficiency.

[0034] Particulate matter collector: Model PG-100, which uses high-efficiency filter material and reasonable structural design, can effectively collect particulate matter that passes through the filter cloth. It has high collection efficiency and facilitates subsequent weighing and analysis.

[0035] Balance: FA2004N model, with an accuracy of 0.1mg, can accurately weigh the collected particulate matter, providing a reliable data basis for calculating filtration efficiency.

[0036] Self-cleaning ability test: Self-cleaning test device: self-made, mainly composed of a dust-laden airflow generation system, filter cloth installation fixture, resistance measurement system, etc. It can simulate the dust accumulation and self-cleaning process of the filter cloth under actual working conditions and accurately measure the resistance change of the filter cloth.

[0037] Resistance measuring instrument: ZXY-1, measuring range 0-2000Pa, accuracy 1Pa, can monitor the resistance change of filter cloth in real time during dust accumulation and self-cleaning process, providing accurate data support for the evaluation of self-cleaning ability.

[0038] Temperature resistance test: High-temperature drying oven: DHG-9070A model, with a temperature range of room temperature to 300℃ and a temperature fluctuation of ±1℃, which can provide a stable high-temperature environment to meet the requirements of filter cloth temperature resistance performance testing.

[0039] Dimensional measuring tools: calipers, rulers, etc., with an accuracy of 0.02mm, are used to measure the dimensional changes of the filter cloth at different temperatures and to evaluate its temperature resistance stability.

[0040] Mechanical performance testing instruments, such as tensile testing machines and universal testing machines, are used to measure the mechanical properties of filter cloth after high-temperature treatment, such as tensile strength and elongation, and to evaluate the influence of its temperature resistance on its mechanical properties.

[0041] Running resistance test: Resistance testing device: Similar to the resistance measurement system in the self-cleaning ability testing device, it mainly consists of an air supply system, filter cloth mounting fixture, pressure sensor, etc., and can accurately measure the resistance change of the filter cloth during the air introduction process.

[0042] Air compressor: ZW-0.36 / 7 model, providing a stable clean air source to meet testing requirements at different flow rates.

[0043] Flow meter: LZB-4 type, with a measurement range of 0-10m³ / h and an accuracy of 1%, used to accurately control the airflow rate entering the filter cloth, ensuring the accuracy and comparability of test results.

[0044] Example 1: A composite high-temperature resistant filter cloth and its preparation method, specifically including the following steps: Preparation of the base fabric layer: Weigh out 40 parts of basalt fiber, 30 parts of aramid fiber, and 20 parts of polyphenylene sulfide fiber. Open and card the basalt fiber, aramid fiber, and polyphenylene sulfide fiber separately, then blend the carded fibers to form a blended yarn. Weave the blended yarn using a plain weave method to form the base fabric layer.

[0045] Coating preparation: Preparation of silicone-modified acrylic resin: The acrylic resin and silicone monomer are mixed in a mass ratio of 4:1, an initiator is added, and the mixture is reacted at 80°C for 4 hours. The amount of initiator is 1% of the total mass of the acrylic resin and silicone monomer.

[0046] Nano-titanium dioxide was heat-treated at 350℃ for 1.5 hours and then cooled to room temperature; hydrophilic nano-silica was treated at 90℃ for 45 minutes in a vacuum environment.

[0047] The silicone-modified acrylic resin was added to a high-speed disperser and pre-dispersed at 1800 r / min for 12 minutes at 45°C. Then, the pretreated nano-titanium dioxide, hydrophilic nano-silica and silane coupling agent KH-560 were slowly added to the disperser and stirred for 1.5 hours to ensure that the components were fully mixed. During this process, the speed of the disperser was gradually increased to 2800 r / min to obtain a preliminary coating mixture.

[0048] The initial coating mixture was transferred to an ultrasonic device and ultrasonically treated at an ultrasonic frequency of 50 kHz for 45 minutes.

[0049] Transfer the ultrasonically treated coating mixture back to the mixing container, add the amino resin curing agent at 35°C, and stir at 900 r / min for 50 minutes.

[0050] The coating mixture containing the curing agent was placed in a vacuum environment with the vacuum level maintained at -0.09 MPa and the degassing time was 15 minutes.

[0051] The base fabric layer is immersed in the deaerated coating mixture for 4 minutes, and then rolled with rollers to control the coating thickness to 20 μm. After that, the coated base fabric layer is pre-cured at 90°C for 2.5 minutes and then cured at 130°C for 4 minutes to obtain a composite high-temperature resistant filter cloth.

[0052] Example 2: Specifically includes the following steps: Preparation of the base fabric layer: Weigh out 35 parts of basalt fiber, 35 parts of aramid fiber, and 25 parts of polyphenylene sulfide fiber. Open and card the basalt fiber, aramid fiber, and polyphenylene sulfide fiber respectively, then blend the carded fibers to form a blended yarn. Weave the blended yarn into the base fabric layer using a twill weave method.

[0053] Coating preparation: Preparation of silicone-modified acrylic resin: The acrylic resin and silicone monomer are mixed in a mass ratio of 3:1, an initiator is added, and the mixture is reacted at 70°C for 5 hours. The amount of initiator is 1.5% of the total mass of the acrylic resin and silicone monomer.

[0054] Nano-titanium dioxide was heat-treated at 300℃ for 2 hours and then cooled to room temperature; hydrophilic nano-silica was treated at 80℃ for 60 minutes in a vacuum environment.

[0055] Organosilicon-modified acrylic resin was added to a high-speed disperser and pre-dispersed at 2000 r / min for 15 minutes at 40°C. Then, the pretreated nano-titanium dioxide, hydrophilic nano-silica and silane coupling agent KH-550 were slowly added to the disperser and stirred for 2 hours to ensure that the components were fully mixed. During this process, the speed of the disperser was gradually increased to 3000 r / min to obtain a preliminary coating mixture.

[0056] The initial coating mixture was transferred to an ultrasonic device and ultrasonically treated at an ultrasonic frequency of 40 kHz for 60 minutes.

[0057] Transfer the ultrasonically treated coating mixture back to the mixing container, add the amino resin curing agent at 30°C, and stir at 1000 r / min for 60 minutes.

[0058] The coating mixture containing the curing agent was placed in a vacuum environment with the vacuum level maintained at -0.08 MPa and the degassing time was 20 minutes.

[0059] The base fabric layer is immersed in the deaerated coating mixture for 5 minutes, and then rolled with rollers to control the coating thickness to 15 μm. After that, the coated base fabric layer is pre-cured at 80°C for 3 minutes and then cured at 120°C for 5 minutes to obtain a composite high-temperature resistant filter cloth.

[0060] Example 3: Specifically includes the following steps: Preparation of the base fabric layer: Weigh out 45 parts of basalt fiber, 25 parts of aramid fiber, and 20 parts of polyphenylene sulfide fiber. Open and card the basalt fiber, aramid fiber, and polyphenylene sulfide fiber separately, then blend the carded fibers to form a blended yarn. Weave the blended yarn using a plain weave method to form the base fabric layer.

[0061] Coating preparation: Preparation of silicone-modified acrylic resin: The acrylic resin and silicone monomer are mixed in a mass ratio of 5:1, an initiator is added, and the mixture is reacted at 90°C for 3 hours. The amount of initiator is 0.5% of the total mass of the acrylic resin and silicone monomer.

[0062] Nano-titanium dioxide was heat-treated at 400℃ for 1 hour and then cooled to room temperature; hydrophilic nano-silica was treated at 100℃ for 30 minutes in a vacuum environment.

[0063] Organosilicon-modified acrylic resin was added to a high-speed disperser and pre-dispersed at 1500 r / min for 10 minutes at 50°C. Then, the pretreated nano-titanium dioxide, hydrophilic nano-silica and silane coupling agent KH-550 were slowly added to the disperser and stirred for 1 hour to ensure that the components were fully mixed. During this process, the speed of the disperser was gradually increased to 2500 r / min to obtain a preliminary coating mixture.

[0064] The initial coating mixture was transferred to an ultrasonic device and ultrasonically treated at an ultrasonic frequency of 60 kHz for 30 minutes.

[0065] Transfer the ultrasonically treated coating mixture back to the mixing container, add the amino resin curing agent at 40°C, and stir at 800 r / min for 45 minutes.

[0066] The coating mixture containing the curing agent was placed in a vacuum environment with the vacuum level maintained at -0.1 MPa and the degassing time was 10 minutes.

[0067] The base fabric layer is immersed in the deaerated coating mixture for 3 minutes, and then rolled with rollers to control the coating thickness to 25 μm. After that, the coated base fabric layer is pre-cured at 100°C for 2 minutes and then cured at 150°C for 3 minutes to obtain a composite high-temperature resistant filter cloth.

[0068] Example 4 specifically includes the following steps: Preparation of the base fabric layer: Weigh out 30 parts of basalt fiber, 40 parts of aramid fiber, and 30 parts of polyphenylene sulfide fiber. Open and card the basalt fiber, aramid fiber, and polyphenylene sulfide fiber separately, then blend the carded fibers to form a blended yarn. Weave the blended yarn using a plain weave method to form the base fabric layer.

[0069] Coating preparation: Preparation of silicone-modified acrylic resin: Acrylic resin and silicone monomer are mixed in a mass ratio of 3.5:1, an initiator is added, and the mixture is reacted at 85°C for 3.5 hours. The amount of initiator is 1.2% of the total mass of acrylic resin and silicone monomer.

[0070] Nano-titanium dioxide was heat-treated at 380℃ for 1.2 hours and then cooled to room temperature; hydrophilic nano-silica was treated at 95℃ for 35 minutes in a vacuum environment.

[0071] The silicone-modified acrylic resin was added to a high-speed disperser and pre-dispersed at 1900 r / min for 13 minutes at 48°C. Then, the pretreated nano-titanium dioxide, hydrophilic nano-silica and silane coupling agent KH-550 were slowly added to the disperser and stirred for 1.8 hours to ensure that the components were fully mixed. During this process, the speed of the disperser was gradually increased to 2900 r / min to obtain a preliminary coating mixture.

[0072] The initial coating mixture was transferred to an ultrasonic device and ultrasonically treated at an ultrasonic frequency of 55 kHz for 50 minutes.

[0073] The ultrasonically treated coating mixture was transferred back to the mixing container, and an amino resin curing agent was added at 38°C. The mixture was stirred at 950 r / min for 55 minutes.

[0074] The coating mixture containing the curing agent was placed in a vacuum environment with the vacuum level maintained at -0.095 MPa and the degassing time was 18 minutes.

[0075] The base fabric layer was immersed in the deaerated coating mixture for 4.5 minutes, and then rolled with rollers to control the coating thickness to 18 μm. After that, the coated base fabric layer was pre-cured at 95°C for 2.8 minutes and then cured at 140°C for 4.5 minutes to obtain a composite high-temperature resistant filter cloth.

[0076] Comparative Example 1, preparation of the base fabric layer: same as in Example 1.

[0077] Coating preparation: Preparation of silicone-modified acrylic resin: The acrylic resin and silicone monomer are mixed in a mass ratio of 4:1, an initiator is added, and the mixture is reacted at 80°C for 4 hours. The amount of initiator is 1% of the total mass of the acrylic resin and silicone monomer.

[0078] No heat treatment of nano-titanium dioxide or vacuum treatment of hydrophilic nano-silica is performed. Nano-titanium dioxide, hydrophilic nano-silica, and silane coupling agent KH-550 are directly added to organosilicon-modified acrylic resin (without pre-dispersed nano-titanium dioxide, etc.), and stirred at 1200 r / min for 1 hour at 45°C to obtain a coating mixture.

[0079] Add the amino resin curing agent to the coating mixture at 35°C and stir at 900 r / min for 50 minutes.

[0080] Vacuum degassing is not performed.

[0081] The base fabric layer was immersed in the coating mixture for 4 minutes, and then rolled with rollers to control the coating thickness to 20 μm. After that, the coated base fabric layer was pre-cured at 90°C for 2.5 minutes and then cured at 130°C for 4 minutes to obtain the control filter cloth.

[0082] Comparative Example 2, Preparation of the base fabric layer: Same as in Example 1.

[0083] Coating preparation: Preparation of silicone-modified acrylic resin: The acrylic resin and silicone monomer are mixed in a mass ratio of 4:1, an initiator is added, and the mixture is reacted at 80°C for 4 hours. The amount of initiator is 1% of the total mass of the acrylic resin and silicone monomer.

[0084] Nano-titanium dioxide was heat-treated at 350℃ for 1.5 hours and then cooled to room temperature; hydrophilic nano-silica was treated at 90℃ for 45 minutes in a vacuum environment.

[0085] The silicone-modified acrylic resin was added to a high-speed disperser and pre-dispersed at 1800 r / min for 12 minutes at 45°C. Then, the pretreated nano-titanium dioxide, hydrophilic nano-silica, and silane coupling agent KH-550 were slowly added to the disperser and stirred for 1.5 hours to ensure that the components were fully mixed. During this process, the speed was not increased (maintained at 1800 r / min) to obtain a preliminary coating mixture.

[0086] The initial coating mixture was transferred to an ultrasonic device and ultrasonically treated at an ultrasonic frequency of 50 kHz for 45 minutes.

[0087] Transfer the ultrasonically treated coating mixture back to the mixing container, add the amino resin curing agent at 35°C, and stir at 900 r / min for 50 minutes.

[0088] The coating mixture containing the curing agent was placed in a vacuum environment with the vacuum level maintained at -0.09 MPa and the degassing time was 15 minutes.

[0089] The base fabric layer was immersed in the deaerated coating mixture for 4 minutes, and then rolled with rollers to control the coating thickness to 20 μm. After that, the coated base fabric layer was pre-cured at 90°C for 2.5 minutes and then cured at 130°C for 4 minutes to obtain the control filter cloth.

[0090] Comparative Example 3, Preparation of the base fabric layer: Same as in Example 1.

[0091] Coating preparation: Preparation of silicone-modified acrylic resin: The acrylic resin and silicone monomer are mixed in a mass ratio of 4:1, an initiator is added, and the mixture is reacted at 80°C for 4 hours. The amount of initiator is 1% of the total mass of the acrylic resin and silicone monomer.

[0092] Nano-titanium dioxide was heat-treated at 350℃ for 1.5 hours and then cooled to room temperature; hydrophilic nano-silica was treated at 90℃ for 45 minutes in a vacuum environment.

[0093] The silicone-modified acrylic resin was added to a high-speed disperser and pre-dispersed at 1800 r / min for 12 minutes at 45°C. Then, the pretreated nano-titanium dioxide, hydrophilic nano-silica and silane coupling agent KH-550 were slowly added to the disperser and stirred for 1.5 hours to ensure that the components were fully mixed. During this process, the speed of the disperser was gradually increased to 2800 r / min to obtain a preliminary coating mixture.

[0094] No ultrasonic treatment is performed.

[0095] Transfer the initial coating mixture back to the mixing container, add the amino resin curing agent at 35°C, and stir at 900 rpm for 50 minutes.

[0096] The coating mixture containing the curing agent was placed in a vacuum environment with the vacuum level maintained at -0.09 MPa and the degassing time was 15 minutes.

[0097] The base fabric layer was immersed in the deaerated coating mixture for 4 minutes, and then rolled with rollers to control the coating thickness to 20 μm. After that, the coated base fabric layer was pre-cured at 90°C for 2.5 minutes and then cured at 130°C for 4 minutes to obtain the control filter cloth.

[0098] Comparative Example 4: Purchase commercially available high-temperature resistant filter cloth, model KQXCTQB, as a comparative test sample. See Table 1 for detailed official parameters. Table 1 Official Test Data for High Temperature Resistant Filter Cloth

[0099] Examples 1, 2, 3, and 4, Comparative Examples 1, 2, and 3, and a commercially available high-temperature resistant filter cloth of model KQXCTQB were used as comparative test samples. The test items were numbered sequentially as 2024-NGWLB-1, 2024-NGWLB-2, 2024-NGWLB-3, 2024-NGWLB-4, 2024-NGWLB-5, 2024-NGWLB-6, 2024-NGWLB-7, and 2024-NGWLB-8. High-temperature resistance and filtration efficiency were tested, and the average value was taken. Specific test results are shown in Table 2. Table 2. Test results of high-temperature resistance and filtration efficiency of high-temperature resistant filter cloth

[0100] The test results show that the high-temperature resistant filter cloths prepared in Examples 1-4 are significantly superior to the comparative test samples in terms of high-temperature resistance and filtration efficiency. The silicone-modified acrylic resin and other components in the coating form a more stable structure after the optimized preparation process, enabling them to withstand higher temperatures. Comparative Example 1, due to the lack of pretreatment of the nanomaterials and a rough preparation process, exhibits a significant decrease in high-temperature resistance. The examples also outperformed the comparative test samples in filtration efficiency, thanks to the effective combination of fibers in the base fabric layer for dust interception and the adsorption and capture of fine dust by the nano-titanium dioxide and hydrophilic nano-silica in the coating under good dispersion. Comparative Example 1 had lower filtration efficiency due to poor dispersion of nanomaterials, while Comparative Examples 2 and 3 also had lower filtration efficiency than the examples due to problems such as nanoparticle agglomeration caused by missing process steps.

[0101] Examples 1, 2, 3, and 4, Comparative Examples 1, 2, and 3, and a commercially available high-temperature resistant filter cloth of model KQXCTQB were used as comparative test samples. The test items were numbered sequentially as 2024-NGWLB-1, 2024-NGWLB-2, 2024-NGWLB-3, 2024-NGWLB-4, 2024-NGWLB-5, 2024-NGWLB-6, 2024-NGWLB-7, and 2024-NGWLB-8. Self-cleaning ability and coating-base fabric adhesion were tested, and the average values ​​were taken. Specific test results are shown in Table 3. Table 3. Test results of self-cleaning ability and coating-base fabric adhesion of high temperature resistant filter cloth

[0102] The test results show that the self-cleaning ability of the examples is strong because the hydrophilic nano-silica can better form a hydrophilic layer on the coating surface after treatment, and the entire coating preparation process ensures that the components are evenly distributed, making the dust and water combine and slide off more smoothly. In Comparative Example 1, the untreated nanomaterials and rough process resulted in poor self-cleaning ability; in Comparative Example 2, the nanoparticles were not well dispersed because the dispersion speed was not increased; and in Comparative Example 3, the lack of ultrasonic treatment led to agglomeration, all of which affected the self-cleaning ability. Comparative Example 4 did not have the corresponding self-cleaning ability. The good adhesion between the coating and the base fabric in the examples is due to the thorough dispersion and pretreatment of the components during coating preparation, as well as the reasonable coating and curing processes, which resulted in strong chemical bonding and physical adsorption between the coating and the base fabric. Comparative Example 1 showed weak adhesion due to process defects; Comparative Examples 2 and 3 also had weaker adhesion due to missing or incomplete processes; and Comparative Example 4 also showed significantly weaker adhesion than the examples.

[0103] The above are merely specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent substitutions, or modifications made based on the present invention to solve essentially the same technical problems and achieve essentially the same technical effects are all covered within the protection scope of the present invention.

Claims

1. A composite high-temperature resistant filter cloth, characterized in that: The product comprises a base fabric layer and a coating applied to the surface of the base fabric layer. The base fabric layer is composed of the following fibers in parts by weight: 30-50 parts basalt fiber, 20-40 parts aramid fiber, and 10-30 parts polyphenylene sulfide fiber. The coating is composed of the following components in parts by weight: 40 parts silicone-modified acrylic resin, 10 parts nano titanium dioxide, 10 parts hydrophilic nano silica, 3 parts coupling agent, and 5 parts curing agent. The preparation steps of the coating are as follows: Step 1, Pretreatment: Heat treat the nano-titanium dioxide at 300-400℃ for 1-2 hours to remove surface impurities and enhance its photocatalytic activity. After heat treatment, cool the nano-titanium dioxide to room temperature for later use. Hydrophilic nano-silica was treated in a vacuum environment at 80-100℃ for 30-60 minutes to further improve its hydrophilicity and dispersibility. The treated hydrophilic nano-silica was then put into use. Step 2, Mixing and Dispersion: Add the silicone-modified acrylic resin to a high-speed disperser and pre-disperse it for 10-15 minutes at 40-50℃ and a speed of 1500-2000 r / min. Then, the pretreated nano-titanium dioxide, hydrophilic nano-silica and coupling agent are slowly added to the disperser and stirred for 1-2 hours to ensure that the components are fully mixed and uniform, thus obtaining a preliminary coating mixture. During this process, the speed of the disperser is gradually increased to 2500-3000 r / min to ensure good dispersion of the nanoparticles. Step 3, Ultrasonic treatment: Transfer the preliminary coating mixture to an ultrasonic device and ultrasonically treat it at an ultrasonic frequency of 40-60kHz for 30-60 minutes to further break up the agglomeration of nanoparticles and make the coating system more uniform and stable. Step 4: Adding and stirring the curing agent: Transfer the ultrasonically treated coating mixture back to the mixing container, add the curing agent at 30-40℃, and stir at 800-1000r / min for 45-60 minutes to ensure that the curing agent is evenly dispersed in the coating system; Step 5, Vacuum Degassing: Place the coating mixture containing the curing agent in a vacuum environment, maintaining the vacuum level at -0.08MPa to -0.1MPa, and degas for 10-20 minutes to remove air bubbles from the coating.

2. The composite high-temperature resistant filter cloth according to claim 1, characterized in that: The preparation method of the organosilicon-modified acrylic resin is as follows: the acrylic resin and organosilicon monomer are mixed in a mass ratio of 3:1-5:1, an initiator is added, and the mixture is reacted at 70-90℃ for 3-5 hours. The amount of initiator is 0.5%-1.5% of the total mass of the acrylic resin and organosilicon monomer.

3. The composite high-temperature resistant filter cloth according to claim 1, characterized in that: The coupling agent is silane coupling agent KH-550.

4. The composite high-temperature resistant filter cloth according to claim 1, characterized in that: The curing agent is an amino resin curing agent.

5. The composite high-temperature resistant filter cloth according to claim 1, characterized in that: The nano-titanium dioxide has a particle size of 20-50 nm, and the hydrophilic nano-silica has a particle size of 10-30 nm.

6. The composite high-temperature resistant filter cloth according to claim 1, characterized in that: The preparation method of the base fabric layer includes the following steps: opening and carding basalt fiber, aramid fiber and polyphenylene sulfide fiber respectively, then blending the carded fibers to form blended yarn, and then weaving the blended yarn to form the base fabric layer, the weaving method being plain weave or twill weave.

7. A method for preparing a composite high-temperature resistant filter cloth as described in any one of claims 1-6, characterized in that: The preparation steps of the composite high-temperature resistant filter cloth coating are as follows: A1. Coating application: The base fabric layer is immersed in the degassed coating mixture for 3-5 minutes, and then rolled with rollers to control the coating thickness to 10-30μm; A2. Curing of the coating: The coated base fabric layer is then pre-cured at 80-100℃ for 2-3 minutes, and then cured at 120-150℃ for 3-5 minutes to fully cure the coating and obtain the composite filter cloth.

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