Preparation method of elastic filter material capable of improving ash removal performance

Abstract

The invention discloses a preparation method of an elastic filter material capable of improving ash removal performance, which comprises the following steps: taking silicone rubber as a base material, adding a proper amount of cross-linking agent and catalyst to prepare a pre-cross-linked silicone rubber spinning solution, heating the pre-cross-linked silicone rubber spinning solution, and uniformly dispersing an elastomer by adopting an electrostatic spinning technology to obtain the elastic filter material with good ash removal performance. According to the invention, a multi-stage finishing process of pre-spinning, hot pressing and respinning is creatively adopted, and the spinning solution is uniformly finished to the air purification surface of the filter material, so that a tough elastic film with a three-dimensional interpenetrating network structure is formed on the surface of the filter material, the filter material is endowed with excellent elasticity, and the ash removal performance of the filter material can be effectively improved; and the prepared elastic filter material has the characteristics of high curing efficiency, excellent interface bonding strength, good film uniformity, environmental friendliness and the like, can effectively solve the technical problem of poor ash removal effect caused by insufficient elasticity of the traditional filter material, and has important significance on the adaptability of the filter material to complex working conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of functional finishing of filter materials for bag filters, and specifically relates to a preparation method for improving the dust cleaning performance of filter materials by electrospinning. Background Art

[0002] In the field of industrial production, with the progress of technologies such as high-temperature resistant filter materials and pulse dust cleaning, bag filters have been widely used in the treatment of high-temperature and high-concentration flue gases due to their excellent dust removal performance, and have gradually become one of the dust removal methods with the highest filtration efficiency for industrial dust. However, single organic fiber materials such as polytetrafluoroethylene, polyphenylene sulfide, and aromatic polyimide, which are high-temperature resistant filter materials, often face problems such as limited performance, insufficient mechanical properties, and poor dust cleaning performance under special working conditions. Therefore, the coating filter material composite technology is usually used for improvement, that is, by preparing a functional coating and compositely finishing it on the surface of the filter material, so that these high-temperature filter materials have multifunctional properties such as low resistance, easy dust cleaning, and corrosion resistance, in order to improve their application universality.

[0003] Chinese Patent CN 105986480 A discloses a protective coating, filter material, substrate and its preparation method with a high polytetrafluoroethylene coverage rate and strong adsorption force with filter material fibers. By processing the filter material in a way of stacking a polyelectrolyte layer and a polytetrafluoroethylene (PTFE) nanoparticle layer, the antioxidant performance, acid and alkali corrosion resistance, filtration efficiency and dust cleaning ability of the filter bag are significantly improved, thus effectively extending its service life. However, this preparation process has certain limitations: the process steps of stacking the polyelectrolyte layer and PTFE nanoparticles are relatively complex, which may lead to higher production costs; at the same time, if not properly controlled during the stacking process, the problem of uneven coating thickness is likely to occur, thereby affecting the overall performance of the filter material. Chinese Patent No. CN 104436861A discloses a method for making a high-precision coated filter material. By performing heat setting, cleaning, impregnation and coating treatment on the filter material substrate, the acid and alkali resistance, water resistance, antioxidant property and wear and fold resistance of the filter material are significantly enhanced, further extending the service life of the filter material. But the limitation of this method is that its multi-step processing technology (including heat setting, cleaning, impregnation and coating treatment) may lead to an increase in production costs, and has high requirements for equipment and technology, and there may be certain implementation difficulties in actual applications. To sum up, the filter material coating treatments involved in existing patents all focus on the dust-facing surface, and mainly improve the dust cleaning performance by enhancing the anti-adhesion or water resistance of the filter material surface, while there is no report on the research of improving the dust cleaning performance by finishing the clean gas side to enhance elasticity.

[0004] At present, the preparation methods of silicone rubber functional coatings mainly include the emulsion method and the solvent method. The emulsion method involves dispersing silicone rubber in an aqueous phase and forming a stable emulsion system with the aid of silica sol and emulsifiers. However, this method has a complex process, requiring precise control of the types and ratios of emulsifiers and silica sol, as well as adjustment of process parameters such as pH value and shear rate. The operation steps are cumbersome and the equipment requirements are high. Secondly, due to the presence of the aqueous phase, the prepared silicone rubber emulsion exhibits poor water resistance, heat resistance, and mechanical properties, and is prone to performance degradation especially in high-temperature or high-humidity environments. The solvent method adopts a process route of directly dissolving silicone rubber in organic solvents. Although it simplifies the preparation process compared to the emulsion method, the use of a large amount of organic solvents not only brings environmental problems of volatile organic compound (VOC) emissions but also significantly increases the production cost. Summary of the Invention

[0005] Aiming at the problems of difficult emulsification, complex process flow, and volatile organic compound (VOC) emissions in the dispersion of high-viscosity silicone rubber in the prior art, the present invention proposes a method for preparing an elastic filter material with improved dust cleaning performance. It innovatively proposes to uniformly disperse high-viscosity silicone rubber by regulating electrospinning process parameters to replace traditional organic solvents. This technical solution not only avoids the complex emulsification process in the traditional process but also completely solves the problem of VOC emissions, having the significant advantages of simple process, high efficiency, and environmental protection. In particular, the present invention successfully applies electrospun silicone rubber materials to the field of dust filtration, filling the application blank of electrospinning technology in the preparation of high-permeability silicone rubber elastomers, which conforms to the development concept of green manufacturing. Compared with the traditional method, the present invention shows outstanding process innovation and performance superiority in the direct dispersion of silicone rubber.

[0006] To achieve the above object, the present invention adopts the following technical solutions: A method for preparing an elastic filter material with improved dust cleaning performance, which comprises the following steps: (1) Preparation of silicone rubber spinning solution: Stir and mix end-functionalized polydimethylsiloxane (PDMS), antistatic agent, and reinforcing agent, then add a crosslinking agent and maintain stirring for more than 30 min, and then add a catalyst and a wetting agent, and continuously stir until a uniform and stable pre-crosslinked silicone rubber spinning solution is formed; (2) Preparation of elastic filter material: After heating the obtained pre-crosslinked silicone rubber spinning solution, use electrospinning technology to perform the first loading on the clean gas side of the filter material. After standing at room temperature, perform a leveling treatment using a hot pressing process. After the surface of the filter material is completely cured, perform the second electrospinning loading to ensure uniform loading of the spinning on the surface of the filter material. Then, after drying and curing, form an elastic film on the surface of the filter material, that is, obtain the elastic filter material.

[0007] Further, the end-group functionalized polydimethylsiloxane described in step (1) is any one or more of vinyl-terminated polydimethylsiloxane, hydroxyl-terminated polydimethylsiloxane, amino-terminated polydimethylsiloxane, and hydrogen-containing silicone oil, and its viscosity is 30-15000 cst, preferably 1000-10000 cst.

[0008] Further, the antistatic agent described in step (1) is any one or more of HS-B2, HS-T3, LH, HS-B2, HS-YM, HS-BM02, and the mass ratio of its dosage to the used end-group functionalized polydimethylsiloxane is 0.001-0.02:1.

[0009] Further, the reinforcing agent described in step (1) is any one or more of silica, carbonate, carbon nanotube, nano calcium carbonate, and the mass ratio of its dosage to the used end-group functionalized polydimethylsiloxane is 0.01-0.2:1.

[0010] Further, the crosslinking agent described in step (1) is any one or more of trimethyltriethoxysilane, isobutyltrimethylsilane, tetraethyl orthosilicate, and the mass ratio of its dosage to the used end-group functionalized polydimethylsiloxane is 0.05-0.25:1.

[0011] Further, the catalyst described in step (1) is any one of organotin compounds stannous octoate, dibutyltin dilaurate or titanate catalysts; the mass ratio of its dosage to the used end-group functionalized polydimethylsiloxane is 0.001-0.02:1.

[0012] Further, the wetting agent described in step (1) is any one of Sivel 8378, JH-4020, TEGO 245, HT-198, HT-105, OT-75, PE-100, and its mass proportion in the obtained pre-crosslinked silicone rubber spinning solution is 0.001%-0.07%.

[0013] Further, the filter material described in step (2) is any one of PPS laminated filter material, PTFE laminated filter material, PET laminated filter material, PPS&PTFE laminated filter material, P32 laminated filter material, PI laminated filter material, and various needle punched felts, hydroentangled felts, needle punched and hydroentangled composite felts that are not limited to laminated filter materials.

[0014] Further, before use, the filter material in step (2) needs to be ultrasonically cleaned with absolute ethanol for 0.2-1.5 h to remove fine particles and grease on the surface and in the internal pores of the filter material.

[0015] Further, the process conditions for electrospinning in step (2) are as follows: voltage 20 - 40 kV, receiving distance 5 - 10 cm, temperature of the spinning solution 45 - 65 °C, flow rate 0.1 - 2 mL / h, and ambient temperature 20 - 30 °C.

[0016] Further, after the first electrospinning in step (2) is completed, it needs to be placed at room temperature for 10 - 20 min.

[0017] Further, the temperature for hot pressing in step (2) is 40 - 100 °C, the pressure is 0.2 - 0.6 MPa, and the time is 2 - 20 s.

[0018] Further, the temperature for curing in step (2) is 25 - 120 °C, and the time is 0.2 - 2 h.

[0019] Further, the temperature for drying and curing in step (2) is 60 - 120 °C, and the time is 0.5 - 3 h.

[0020] Further, the total finishing amount of the pre-crosslinked silicone rubber spinning solution on the clean gas side of the filter medium is 10 - 120 g / m 2 , where, during the first electrospinning, its loading amount is 5 - 10 g / m 2 ; during the second electrospinning, its loading amount is 5 - 100 g / m 2 .

[0021] Aiming at the problems existing in the traditional methods of directly spraying, impregnating and loading on the filter medium, such as uneven loading on the filter medium substrate, insufficient interfacial bonding force and VOC emission pollution, the present invention proposes a new process for preparing elastic filter media by a three-step method of "pre-spinning - hot pressing - re-spinning" based on electrospinning. Firstly, through the pre-spinning combined with the hot pressing process, the clean gas side of the filter medium is leveled to provide a uniform substrate for the subsequent construction of the elastic film, and by precisely controlling the electrospinning parameters, the loading amount of the elastomer is controlled, promoting the formation of a three-dimensional interpenetrating network structure between the silicone rubber and the filter medium fibers, effectively solving the problems of difficult interfacial bonding between the silicone rubber and the filter medium substrate and serious environmental pollution; at the same time, the present invention innovatively adopts the strategy of step-by-step spinning and loading, while ensuring the uniformity of the silicone rubber elastomer, effectively avoiding the negative impact of the traditional process on the air permeability of the filter medium, realizing the synergistic optimization of the uniformity of the elastomer and the air permeability of the substrate, and having significant process innovation and application value.

[0022] Compared with the prior art, the present invention has the following advantages: 1. The present invention innovatively adopts a solvent-free electrospinning dispersion technology, and by precisely controlling key parameters such as voltage, spinning distance, solution temperature, etc., it replaces the role of traditional organic solvents in reducing the viscosity, surface tension of the silicone rubber solution and increasing the conductivity of the solution.

[0023] It solves the problems of VOC emission pollution caused by the use of organic solvents or emulsifiers during the dispersion of traditional high-viscosity silicone rubber. Its preparation process is simple and efficient, without using any solvents, being green and safe, and greatly saving production costs.

[0024] 2. Compared with traditional post-treatment modification processes such as spraying or dipping methods, the present invention uses an advanced electrospinning dispersion technology to achieve uniform loading of silicone rubber on the clean gas side of the filter media, overcoming the problems of low loading strength and uneven loading existing in traditional methods, and forming a continuous and dense network elastomer structure of silicone rubber elastomer on the surface of the filter media.

[0025] 3. The present invention innovatively uses a multi-stage finishing process of "pre-spinning - hot pressing and leveling - re-spinning". Through the synergistic effect of stage-by-stage spinning and hot pressing and leveling technologies, a uniform and dense nanofiber structure transition layer of silicone rubber is formed on the surface of the substrate, and a second spinning is carried out by precisely controlling the spinning parameters to construct an elastic functional layer on the surface of the leveled filter media, so as to precisely control the key properties such as the air permeability and thickness of the silicone rubber elastomer filter media, thereby meeting the requirements of different application scenarios. Description of the Drawings

[0026] Figure 1 It is a process flow chart for preparing an elastic filter media by the multi-stage finishing process of "pre-spinning - hot pressing and leveling - re-spinning" of the present invention.

[0027] Figure 2 It is a scanning electron microscope image of PPS elastic filter media with the same loading amount prepared in the comparative example (a) and Example 1 (b).

[0028] Figure 3 It is a comparison chart of the dust stripping rate (K) of PPS elastic filter media with different finishing amounts prepared in Example 1 and the original filter media.

[0029] Figure 4 It is a comparison chart of the dust stripping rate (K) of PET, PI and P32 elastic filter media with a finishing amount of 22.45 g / m 2 prepared in Example 2 and the original filter media.

[0030] Figure 5 It is a comparison chart of the maximum reverse acceleration of PPS elastic filter media with different finishing amounts prepared in Example 1 and the original filter media.

[0031] Figure 6 It is a comparison chart of the maximum reverse acceleration of PET, PI and P32 elastic filter media with a finishing amount of 22.45 g / m 2 prepared in Example 2 and the original filter media. Detailed Embodiments

[0032] As Figure 1 , a method for preparing an elastic filter medium with improved dust cleaning performance, comprising the following steps: (1) Preparation of silicone rubber spinning solution: Stir and mix end-functionalized polydimethylsiloxane (PDMS), antistatic agent, and reinforcing agent evenly, then add a crosslinking agent and maintain stirring for more than 30 min, and then add a catalyst and a wetting agent, and continue stirring until a uniform and stable pre-crosslinked silicone rubber spinning solution is formed; (2) Preparation of elastic filter medium: First, ultrasonically clean the filter medium with absolute ethanol for 0.2 - 1.5 h to remove fine particles and grease on the surface and inside the pores of the filter medium. Then, heat the obtained pre-crosslinked silicone rubber spinning solution to 45 - 65 °C, and use electrospinning technology to perform the first loading on the clean gas side of the filter medium, with a loading amount of 5 - 10 g / m 2 . After standing at room temperature for 10 - 20 min, hot press for 2 - 20 s at 40 - 100 °C under a pressure of 0.2 - 0.6 MPa, and then cure at 25 - 120 °C for 0.2 - 2 h and perform the second electrospinning loading, with a loading amount of 5 - 100 g / m 2 . After drying and curing at 60 - 120 °C for 0.5 - 3 h, a layer of elastic film is formed on the surface of the filter medium, that is, an elastic filter medium is obtained, where the total finishing amount of the pre-crosslinked silicone rubber spinning solution on the clean gas side of the filter medium is 10 - 120 g / m 2 .

[0033] Among them, the end-functionalized polydimethylsiloxane in step (1) is any one or more of vinyl-terminated polydimethylsiloxane, hydroxyl-terminated polydimethylsiloxane, amino-terminated polydimethylsiloxane, and hydrogen-containing silicone oil, and its viscosity is 30 - 15000 cst.

[0034] The antistatic agent in step (1) is any one or more of HS-B2, HS-T3, LH, HS-B2, HS-YM, HS-BM02, and the mass ratio of its dosage to the used end-functionalized polydimethylsiloxane is 0.001 - 0.02:1.

[0035] The reinforcing agent in step (1) is any one or more of white carbon black, carbonate, carbon nanotube, nano calcium carbonate, and the mass ratio of its dosage to the used end-functionalized polydimethylsiloxane is 0.01 - 0.2:1.

[0036] The crosslinking agent in step (1) is any one or more of trimethyltriethoxysilane, isobutyltrimethylsilane, tetraethyl orthosilicate, and the mass ratio of its dosage to the used end-functionalized polydimethylsiloxane is 0.05 - 0.25:1.

[0037] The catalyst described in step (1) is any one of organotin compounds stannous octoate, dibutyltin dilaurate or titanate catalysts; the mass ratio of its dosage to the mass of the end-functionalized polydimethylsiloxane used is 0.001~0.02:1.

[0038] The wetting agent described in step (1) is any one of Sivel 8378, JH-4020, TEGO 245, HT-198, HT-105, OT-75, PE-100, and its mass proportion in the obtained pre-crosslinked silicone rubber spinning solution is 0.001%~0.07%.

[0039] The filter material described in step (2) is any one of PPS coated filter material, PTFE coated filter material, PET coated filter material, PPS&PTFE coated filter material, P32 coated filter material, PI coated filter material, and various needle punched felts, hydroentangled felts, needle punched and hydroentangled composite felts that are not limited to coated filter materials.

[0040] The process conditions for electrospinning in step (2) are: voltage 20~40 kV, receiving distance 5~10 cm, spinning solution flow rate 0.1~2 mL / h, and ambient temperature 20~30°C.

[0041] In order to make the content of the present invention easier to understand, the technical solutions of the present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited thereto.

[0042] The embodiments of the present invention are described in detail below. The examples are intended to explain the present invention and should not be construed as limiting the present invention. Reagents or instruments not indicated by the manufacturer can be obtained as conventional products through commercial purchase.

[0043] I. Preparation method of elastic filter material Example 1 Weigh 10 g of hydroxyl-terminated polydimethylsiloxane with a viscosity of 5000 cst, add 0.03 g of antistatic agent HS-B2 and 0.3 g of reinforcing agent fumed silica, stir and mix well, then add 1.0 g of tetraethyl orthosilicate, stir with a magnetic stirrer at 400 r / min for 30 min, then add 0.01 g of dibutyltin dilaurate and 0.006 g of wetting agent Sivel 8378, and continue to stir and mix evenly to obtain a pre-crosslinked silicone rubber spinning solution; Cut the PPS coated filter media into round pieces with a diameter of about 15 cm. After ultrasonic cleaning with absolute ethanol for 20 min to remove fine particles and grease on the surface and in the internal pores of the filter media, first place them in an oven at 100 °C for 2 h of drying, and then place them in a vacuum drying oven for drying at 120 °C to remove the internal moisture of the filter media. Then heat the above pre-crosslinked silicone rubber spinning solution to 60 °C, and perform the first electrospinning on the clean gas side of the filter media (the process conditions for electrospinning are: voltage 25 kV, receiving distance 7 cm, spinning solution flow rate 1 mL / h, ambient temperature 25 °C), and its loading amount is 5 g / m 2 , after removing the filter media and placing it at room temperature for 10 min, hot press it at 80 °C and a pressure of 0.4 MPa for 4 s to make it flat, and then place it in a constant temperature forced air drying oven for drying at 80 °C for 0.5 h for curing. Then perform the second electrospinning under the same process conditions, and its loading amount is 5 - 110 g / m 2 , and then dry and cure at 80 °C for 2 h to form an elastic film on the surface of the filter media, that is, obtain PPS elastic filter media with different finishing amounts prepared by the electrospinning method.

[0044] Example 2 Weigh 20 g of hydroxyl-terminated polydimethylsiloxane with a viscosity of 10000 cst, add 0.05 g of antistatic agent HS-T3 and 0.8 g of reinforcing agent fumed silica, stir and mix well, then add 1.5 g of tetraethyl orthosilicate, use a magnetic stirrer to stir at 400 r / min for 30 min, then add 0.03 g of dibutyltin dilaurate and 0.09 g of wetting agent Sivel 8378, and continue to stir and mix evenly to obtain a pre-crosslinked silicone rubber spinning solution; Cut the PET, PI and P32 coated filter media into round pieces with a diameter of about 15 cm respectively. After ultrasonic cleaning with absolute ethanol for 20 min to remove fine particles and grease on the surface and in the internal pores of the filter media, first place them in an oven at 100 °C for 2 h of drying, and then place them in a vacuum drying oven for drying at 120 °C to remove the internal moisture of the filter media. Then heat the above pre-crosslinked silicone rubber spinning solution to 50 °C, and perform the first electrospinning on the clean gas side of the above three filter media respectively (the process conditions for electrospinning are: voltage 30 kV, receiving distance 8 cm, spinning solution flow rate 0.5 mL / h, ambient temperature 27 °C), and its loading amount is 5 g / m 2 , after removing the filter media and placing it at room temperature for 10 min, hot press it at 50 °C and a pressure of 0.4 MPa for 8 s to make it flat, and then place it in a constant temperature forced air drying oven for drying at 80 °C for 0.5 h for curing. Then perform the second electrospinning under the same process conditions, and its spinning loading amount is 19.5 g / m 2, and then dried and cured at 60 °C for 1 h to form an elastic film on the surface of the filter material, thus obtaining PET, PI and P32 elastic filter materials prepared by the electrospinning method with a finishing amount of 22.45 g / m 2 respectively.

[0045] Comparative example Weigh 10 g of hydroxyl-terminated polydimethylsiloxane with a viscosity of 5000 cst, add 15 ml of ethyl acetate, 0.03 g of antistatic agent HS-B2 and 0.3 g of reinforcing agent fumed silica. After stirring and mixing evenly, add 1.0 g of tetraethyl orthosilicate. Stir with a magnetic stirrer at 400 r / min for 30 min, then add 0.01 g of dibutyltin dilaurate and 0.006 g of wetting agent Sivel 8378, and continue to stir and mix evenly to obtain a pre-crosslinked silicone rubber solution; Cut the PPS coated filter material into round pieces with a diameter of about 15 cm. After ultrasonic cleaning with anhydrous ethanol for 20 min to remove fine particles and grease on the surface and inside the pores of the filter material, first place it in an oven at 100 °C for 2 h, and then place it in a vacuum drying oven at 120 °C to dry to remove the internal moisture of the filter material. Then, the above pre-crosslinked silicone rubber solution is loaded on the clean gas side of the filter material by spraying multiple times, and the loading amount is 22.4 g / m 2 . After removing the filter material and placing it at room temperature for 20 min, it is hot-pressed for 10 s at 80 °C and a pressure of 0.4 MPa for leveling treatment, and then placed in a constant temperature blast drying oven and dried at 80 °C for 0.5 h for curing to form an elastic film on the surface of the filter material, thus obtaining an elastic filter material prepared by the spraying method.

[0046] Figure 2 Figure shows the surface morphology comparison diagram of PPS elastic filter materials with the same loading amount prepared in the comparative example and Example 1. It can be seen from the scanning electron microscope that the PPS elastic filter material prepared by dispersing silicone rubber in a solvent and using the spraying process shows obvious elastomer accumulation phenomenon (a), resulting in serious pore blockage and obvious insufficient interfacial bonding strength with the matrix; while the PPS elastic filter material prepared by the "pre-spinning - hot pressing - re-spinning" process forms a layer of elastic film with relatively uniform pores on the clean gas side of the filter material, and it is tightly combined with the fiber matrix (b).

[0047] Performance test 1. Pulse-jet cleaning performance test The VDI filtration-jet cleaning experiments were carried out on the elastic filter materials prepared in the examples to investigate the pulse-jet cleaning performance of the obtained elastic filter materials. The specific experimental process is as follows: The above elastic filter media and the original filter media were respectively tested for dust cleaning performance through a dust filtration efficiency test system to evaluate the dust cleaning performance of the prepared elastic filter media. The dust cleaning performance of the elastic filter media is represented by the dust stripping rate K, and its calculation formula is as follows. The results are shown in Table 1.

[0048] , where: P is the set resistance of 1000 Pa when triggering dust cleaning; P last is the resistance of the filter media after testing in Pa; P0 is the resistance of the filter media before testing in Pa; Table 1 Comparison of dust stripping rates of PPS elastic filter media prepared in Example 1

[0049] As can be seen from Table 1, in the range of the finishing amount of 10 - 50 g / m 2 , with the increase of the finishing amount, the dust stripping rate of the PPS elastic filter media shows a trend of first increasing and then decreasing, and the elastic filter media with a finishing amount of 22.45 g / m 2 has the best dust cleaning performance. The dust cleaning performances in the three stages of 30C1, 10000 aging, and 30C2 are increased by 15.5%, 68.1%, and 43.8% respectively compared with the original PPS filter media. The possible reason is that the reduction of the air permeability of the filter media caused by the finishing of the elastic coating on the surface of the filter media. However, with the increase of the finishing amount, while the elasticity offsets the increase in the pressure drop caused by the decrease in air permeability, it plays the role of its own elasticity, increasing the maximum reverse acceleration of the filter media during pulse jetting, thereby reducing the residual pressure drop during dust cleaning and improving the dust cleaning performance. But when the finishing amount of the filter media is too high (when the finishing amount is 120 g / m 2 ), its air permeability drops significantly, resulting in a significant reduction in the dust stripping rate during the filtration and dust cleaning process, thus affecting the dust cleaning performance of the filter media. At the same time, through comparison, it can be seen that the air permeability of the elastic filter media prepared by the spraying process in the comparative example is 23.45 L / dm 3 / min, and the dust stripping rates in the three stages of 30C1, 10000 aging, and 30C2 are 65.43%, 42.23%, and 41.26% respectively, which are reduced by 23.6%, 21.1%, and 23.4% respectively compared with the original PPS coated filter media, indicating that directly using the spraying method has a negative effect on improving the elasticity of the filter media, and its dust cleaning performance is greatly reduced.

[0050] Table 2 Comparison of dust stripping rates of different types of elastic filter media prepared in Example 2

[0051] Table 2 presents the dust stripping rates of the clean gas sides of different types of elastic filter materials prepared in Example 2. By comprehensively analyzing the data in Tables 1 and 2, it can be seen that under the condition that the finishing amount is 22.45 g / m 2 , the dust cleaning performance of the four elastic filter materials has been significantly improved. Specifically, for the PPS elastic filter material, when the finishing amount is 22.45 g / m 2 , its dust cleaning performance is the best. The dust cleaning performance in the three stages of 30C1, 10000 aging, and 30C2 has increased by 15.5%, 68.1%, and 43.8% respectively compared with the PPS film-coated filter material (Comparative Example 1); for the PET elastic filter material, when the finishing amount is 22.45 g / m², the dust cleaning performance in the three stages of 30C1, 10000 aging, and 30C2 has increased by 13.6%, 62.6%, and 71.8% respectively compared with the PET film-coated filter material; for the PI elastic filter material, under the same finishing amount, the dust cleaning performance in the three stages of 30C1, 10000 aging, and 30C2 has increased by 15.3%, 56.0%, and 50.2% respectively compared with the PI film-coated filter material; for the P32 elastic filter material, when the finishing amount is 22.45 g / m², the dust cleaning performance in the three stages of 30C1, 10000 aging, and 30C2 has increased by 12.2%, 40.5%, and 41.1% respectively compared with the P32 film-coated filter material. Based on the above analysis, adopting the elastic finishing strategy for different types of filter materials can significantly improve their dust cleaning performance. Among them, the improvement of the dust cleaning performance of the PPS and PET elastic filter materials is particularly significant.

[0052] 2. Test of maximum reverse acceleration performance For the elastic filter materials prepared in the examples, the maximum positive and negative acceleration test experiments were respectively carried out using a vibration acceleration sensor to investigate their elastic properties, and the data sequence of the acceleration changing with time obtained was imported into MATLAB software for spectral analysis. Based on the fast Fourier transform (FFT) algorithm, key parameters such as the dominant frequency and maximum amplitude of different filter material samples were obtained, and the specific data are shown in Table 3.

[0053] Table 3 Comparison of vibration response parameters of elastic filter materials

[0054] The results in Table 3 show that compared with the original film-coated filter material, there are slight differences in the acceleration when the four organic synthetic fiber filter materials undergo the maximum deformation after elastic finishing. Specifically, for the PPS elastic filter material, in the range of 10 - 50 g / m 2 , with the increase of the finishing amount, it shows a trend of first increasing and then decreasing; while for the PET, PI, and P32 elastic filter materials, when the finishing amount is 22.45 g / m 2The maximum reverse acceleration at all shows an increasing trend, increasing by 52%, 48% and 71% respectively compared with the original membrane filter material, which is also consistent with the changing trends of the dust stripping rates given in Tables 1 and 2. In addition, from the data of the maximum amplitude and frequency given in Table 3, it can be seen that compared with PPS, PET, PI, and P32 membrane filter materials, the maximum vibration and frequency show an increasing trend after being treated with silicone rubber elastomer. This experimental result fully proves that the load treatment of the elastomer can effectively enhance the mechanical vibration response of the filter material during the pulse jet cleaning process, thereby generating a greater reverse acceleration and significantly improving the cleaning efficiency.

[0055] The above are only the preferred embodiments of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

Claims

1. A method for preparing an elastic filter medium to improve the dust cleaning performance, characterized in that It includes the following steps: (1) Preparation of silicone rubber spinning solution: Stir and mix the end-functionalized polydimethylsiloxane, antistatic agent and reinforcing agent evenly, then successively add the crosslinking agent, catalyst and wetting agent, and continuously stir until a uniform and stable pre-crosslinked silicone rubber spinning solution is formed; (2) Preparation of elastic filter material: After heating the obtained pre-crosslinked silicone rubber spinning solution, use electrospinning technology to perform the first loading on the clean gas side of the filter material. After hot pressing, leveling and curing, perform the second electrospinning loading to ensure uniform loading of the spinning on the filter material surface. Then, after drying and curing, an elastic film is formed on the filter material surface, that is, an elastic filter material is obtained.

2. The preparation method of an elastic filter material for improving the dust cleaning performance according to claim 1, wherein: The end-functionalized polydimethylsiloxane described in step (1) is any one or more of vinyl-terminated polydimethylsiloxane, hydroxyl-terminated polydimethylsiloxane, amino-terminated polydimethylsiloxane and hydrogen-containing silicone oil, and its viscosity is 30~15000 cst.

3. A method for preparing an elastic filter material for improving the dust cleaning performance according to claim 1, characterized in that: The antistatic agent described in step (1) is any one or more of HS-B2, HS-T3, LH, HS-B2, HS-YM, HS-BM02, and the mass ratio of its dosage to the used end-functionalized polydimethylsiloxane is 0.001~0.02:

1.

4. The preparation method of an elastic filter material for improving the dust cleaning performance according to claim 1, characterized in that: The reinforcing agent described in step (1) is any one or more of white carbon black, carbonate, carbon nanotube, nano calcium carbonate, and the mass ratio of its dosage to the used end-functionalized polydimethylsiloxane is 0.01~0.2:

1.

5. A method for preparing an elastic filter material for improving the dust cleaning performance according to claim 1, characterized in that: The crosslinking agent described in step (1) is any one or more of trimethyltriethoxysilane, isobutyltrimethylsilane, tetraethyl orthosilicate, and the mass ratio of its dosage to the used end-functionalized polydimethylsiloxane is 0.05~0.25:

1.

6. The preparation method of an elastic filter material for improving the dust cleaning performance according to claim 1, characterized in that: The catalyst described in step (1) is any one of the organotin compound stannous octoate, dibutyltin dilaurate or titanate catalyst; the mass ratio of its dosage to the used end-functionalized polydimethylsiloxane is 0.001~0.02:

1.

7. A method for preparing an elastic filter material for improving the dust cleaning performance according to claim 1, characterized in that: The wetting agent described in step (1) is any one of Sivel 8378, JH-4020, TEGO 245, HT-198, HT-105, OT-75, PE-100, and its mass proportion in the obtained pre-crosslinked silicone rubber spinning solution is 0.001%~0.07%.

8. A method for preparing an elastic filter material with improved dust cleaning performance according to claim 1, characterized in that: The process conditions for electrospinning in step (2) are: voltage 20~40 kV, receiving distance 5~10 cm, spinning solution temperature 45~65℃, flow rate 0.1~2 mL / h, ambient temperature 20~30℃.

9. A method for preparing an elastic filter material for improving the dust cleaning performance according to claim 1, characterized in that: The temperature of the hot pressing in step (2) is 40~100 ℃, the pressure is 0.2~0.6 MPa, and the time is 2~20 s; the temperature of the curing is 25~120℃, and the time is 0.2~2 h; the temperature of the drying and curing is 60~120℃, and the time is 0.5~3 h.

10. A method for preparing an elastic filter material with improved dust cleaning performance according to claim 1, characterized in that: In step (2), the total finishing amount of the pre-crosslinked silicone rubber spinning solution on the clean gas side of the filter medium is 10-120 g / m 2 , where, during the first electrospinning, the loading amount is 5-10 g / m 2 ; during the second electrospinning, the loading amount is 5-100 g / m 2 .

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