Preparation method of high-temperature-resistant and corrosion-resistant composite spunlace filter material

Abstract

The invention relates to the technical field of high-temperature gas filtration, and particularly discloses a preparation method of a high-temperature-resistant and corrosion-resistant composite spunlace filter material. The preparation method of the filter material comprises the following steps: pretreating the PTFE short fibers, the glass fibers and the high-temperature-resistant glass fiber woven base cloth; mixing the pretreated glass fibers with PI fibers to obtain mixed fibers; the pretreated PTFE fibers and the mixed fibers are respectively subjected to carding, net forming and net laying, the pretreated PTFE fibers form a surface layer, the mixed fibers form a bottom layer, pretreated high-temperature-resistant glass fiber woven base cloth is used as middle base cloth, pre-needled reinforcement and winding are performed to obtain a pre-needled felt, and the pre-needled felt is subjected to spunlace reinforcement, drying and winding to obtain a filter material plain felt; dipping, shaping and laminating the filter material to obtain the high-temperature-resistant and corrosion-resistant composite spunlace filter material. According to the method, a high-temperature-resistant system for increasing the temperature-resistant threshold value layer by layer is formed, the corrosion resistance is enhanced, and synergistic improvement of high temperature resistance and strong corrosion resistance is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of high-temperature gas filtration, and particularly to a preparation method of a high-temperature resistant and corrosion resistant composite spunlace filter material. Background Art

[0002] With the development of industrial technology, the filtration requirements for high-temperature and highly corrosive gases or liquids are increasing day by day. Especially in the fields of chemical industry, metallurgy, waste incineration power generation, thermal power generation, and high-temperature flue gas treatment, higher requirements are put forward for the temperature resistance, chemical corrosion resistance, mechanical strength, and filtration accuracy of filtration materials. Ordinary polyester, polypropylene, or fiberglass filter materials are prone to fiber degradation, structural damage, or performance decline in harsh environments such as high temperatures above 200°C, strong acids, strong alkalis, and organic solvents, resulting in short service life, decreased filtration efficiency, and even potential safety hazards.

[0003] Existing filter materials are mostly prepared by processes such as needling and spunbonding. The fiber entanglement density is insufficient, resulting in uneven pore distribution and difficulty in balancing the requirements of high filtration accuracy and low pressure drop. Although the spunlace process can achieve three-dimensional fiber entanglement through high-pressure water jets to improve the uniformity and denseness of the material, the conventional spunlace process has poor adaptability to high-performance fibers such as aramid and PI fibers, with a high fiber damage rate, and the temperature and corrosion resistance synergistic effect of the composite material has not been effectively developed.

[0004] Therefore, there is an urgent need to develop a composite spunlace filter material and its preparation method to achieve a synergistic improvement in high-temperature resistance and strong corrosion resistance and meet the industrial filtration requirements under extreme working conditions. Summary of the Invention

[0005] In order to synergistically improve the high-temperature resistance and strong corrosion resistance of the filter material, the present application provides a preparation method of a high-temperature resistant and corrosion resistant composite spunlace filter material.

[0006] The preparation method of a high-temperature resistant and corrosion resistant composite spunlace filter material provided by the present application adopts the following technical solutions:

[0007] A preparation method of a high-temperature resistant and corrosion resistant composite spunlace filter material includes the following steps:

[0008] S1. Spray an antistatic agent on PTFE short fibers, stack them at a constant temperature to obtain pretreated PTFE short fibers; rinse and dry glass fibers to obtain pretreated glass fibers; impregnate a high-temperature resistant fiberglass woven base fabric with PTFE emulsion and dry it to obtain a pretreated high-temperature resistant fiberglass woven base fabric;

[0009] S2. Mix the pretreated glass fibers and PI fibers according to a weight ratio of (75-95):(5-25) to obtain mixed fibers;

[0010] S3. Card, form a web, and lay the pretreated PTFE fibers and the mixed fibers respectively. The pretreated PTFE fibers form the surface layer, the mixed fibers form the bottom layer, and the intermediate base fabric uses a pretreated high-temperature resistant fiberglass woven base fabric. After pre-needling reinforcement, wind it into a roll to obtain a pre-needled felt. Then, subject the pre-needled felt to hydroentangling reinforcement, drying, and winding to obtain a filter media base felt.

[0011] S4. Immerse the filter media base felt in a finishing agent. After immersion, squeeze out the liquid, dry and shape it, and apply a film to obtain a high-temperature resistant and corrosion resistant composite hydroentangled filter media.

[0012] By adopting the above technical solution, the PTFE fibers are used as the surface layer, directly contacting the corrosive gas / liquid, and preferentially undertaking corrosion protection. Compared with ordinary blended composite filter media, it can not only improve the corrosion resistance and bending resistance of the surface layer fibers, but also improve the bonding ability between the fiberglass filter media fibers by increasing the path of the PTFE fibers, thereby improving the post-treatment formula and not using silicone oil and other coupling agents, making the production process more environmentally friendly. PI fibers are resistant to oxidizing acids, making up for the shortcoming of fiberglass in acid resistance. Therefore, the fiberglass / PI blended layer maintains the structural strength at high temperatures and prevents the micropores from expanding due to thermal deformation of the surface layer. The PTFE-reinforced fiberglass base fabric serves as a support skeleton, bearing mechanical stress and blocking the high-temperature heat conduction to the interior of the filter media.

[0013] Moreover, through the above hydroentangling reinforcement process, the present application forces the PTFE and the fiberglass / PI fibers to interpenetrate and entangle with each other under high-pressure water flow, improving the interfacial bonding strength and the dust removal rate. Therefore, the method of the present application forms a high-temperature resistant system with gradually increasing temperature resistance thresholds from the surface layer to the bottom layer to the base fabric, avoiding local overheating failure, enhancing the corrosion resistance of the filter media, and achieving the coordinated improvement of high-temperature resistance and strong corrosion resistance.

[0014] In a specific feasible implementation, in step S3, the grammage of the surface layer is 120 - 140 g / m 2 .

[0015] By adopting the above technical solution, the surface layer with a grammage of 120 - 140 g / m 2 has a lower grammage, allowing the water needles under the hydroentangling pressure of the present application to fully penetrate to the bottom layer, promoting the interpenetration and entanglement of the PTFE fibers and the fiberglass / PI fibers, and improving the interfacial peel strength. Moreover, the low-grammage surface layer preferentially intercepts fine particles, and the bottom layer and the base fabric bear the large-particle load, avoiding the blockage of a single layer and extending the service life.

[0016] In a specific feasible implementation, in step S3, the grammage of the bottom layer is 200 - 220 g / m 2 .

[0017] By adopting the above technical solution, the grammage of 200 - 220 g / m 2The bottom layer has a relatively large thickness, which helps to block the penetration of corrosive media to the base fabric. Moreover, as the transition layer between the surface layer and the base fabric, the gram weight is 200-220g / m 2 It can provide sufficient mechanical strength to withstand the filtration pressure difference and air flow scouring, and avoid collapse or deformation.

[0018] In a specific feasible implementation, in step S1, the gram weight of the high-temperature resistant fiberglass woven base fabric is 380-400g / m 2 。

[0019] In a specific feasible implementation, in step S1, the glass fiber is heat-treated at 420-480°C, cooled to room temperature, immersed in a dilute hydrochloric acid solution with a mass concentration of 1-1.5%, and after the impregnation is completed, it is rinsed and dried to obtain the pretreated glass fiber.

[0020] By adopting the above technical solution, heat treatment at 420-480°C can thoroughly remove organic pollutants such as grease and dust adsorbed during fiber production and transportation, and avoid impurity interference with interface bonding in subsequent processes. Impregnation with 1-1.5% dilute hydrochloric acid can selectively dissolve the metal oxides on the fiber surface, reduce its reactivity with acid and alkali media in high-temperature / corrosive environments, and reduce the corrosion risk. Moreover, the dilute hydrochloric acid impregnation treatment can partially etch the fiber surface, reduce brittleness, improve the fiber bending strength, make it more resistant to high-pressure water flow impact in the hydroentangling process, and reduce breakage.

[0021] In a specific feasible implementation, in step S3, the hydroentangling reinforcement is operated according to the following process: five hydroentangling heads are used, and the pre-needled felt is successively passed through 1# 150-180 bar, 2# 130-160 bar, 3# 150-180 bar, 4# 130-160 bar, 5# 150-180 bar, the hydroentangling speed is 4-6 m / min, and after hydroentangling reinforcement, the drying temperature is 100-150°C.

[0022] By adopting the above technical solution, by using the above pressure, it can penetrate the surface layer PTFE fibers and penetrate deep into the interface between the bottom layer and the base fabric to form a three-dimensional interpenetrating network structure, enabling the interface between the bottom layer and the base fabric to be directionally entangled to form a "hook-shaped" fiber interlocking structure, and improving the peel strength. By adjusting the hydroentangling pressure in stages, the synergistic optimization of fiber entanglement strength, interface bonding force and high-temperature and corrosion resistance performance is achieved.

[0023] In a specific feasible implementation, in step S4, the film coating is operated according to the following process: a microporous PTFE film with a thickness of 7-10μm and a pore diameter of 1-1.5μm is laminated to the surface layer, and hot pressing is carried out through an electromagnetic roll, the temperature of the electromagnetic roll is 350-380°C, and after the hot pressing is completed, the film coating is completed.

[0024] By adopting the above technical solution, at a high temperature of 350-380 °C, the film and the surface layer of PTFE fibers are slightly melted on the surface to form a molten blend interface, improving the bonding strength and ensuring the mechanical properties of the substrate. Moreover, the microporous PTFE film with the above thickness and pore size enables the filter material to maintain a good dust removal rate.

[0025] In a specific feasible embodiment, in step S4, the pick-up of the padding is 115%-130%.

[0026] By adopting the above technical solution, a pick-up of 115%-130% ensures that the finishing agent fully penetrates into the fiber gaps to form a continuous protective film, rather than just covering the surface. The upper limit of the pick-up of 130% prevents excessive finishing agent from clogging the pores of the filter material and maintains the air permeability.

[0027] In summary, the present application has the following beneficial effects:

[0028] 1. The method of the present application forms a high-temperature resistant system that gradually increases the temperature resistance threshold from the surface layer → the bottom layer → the base fabric, avoiding local overheating failure and enhancing the corrosion resistance of the filter material, achieving the coordinated improvement of high temperature resistance and strong corrosion resistance.

[0029] 2. The present application realizes the coordinated optimization of fiber entanglement strength, interfacial bonding force, and high temperature and corrosion resistance by adjusting the hydroentangling pressure in stages. Specific Embodiments

[0030] The present application will be further described in detail below with reference to examples and comparative examples.

[0031] Examples

[0032] Example 1

[0033] This example provides a method for preparing a high-temperature and corrosion-resistant composite hydroentangled filter material, which adopts the following steps:

[0034] S1. Spray an antistatic agent on PTFE staple fibers with a fineness of 1.5-3.0 dtex and a length of 40-60 mm, and stack them at a constant temperature of 40 °C for 5 h to obtain pretreated PTFE staple fibers. The antistatic agent in this example is an aqueous solution of antistatic agent 609 with a mass concentration of 10%. Place glass fibers (silica content ≥ 55%, diameter 6-9 μm) in a high-temperature calcination furnace, heat-treat them at 450 °C for 30 minutes, cool them to room temperature, immerse them in a 1% dilute hydrochloric acid solution for ultrasonic cleaning for 10 minutes, rinse them with deionized water until neutral, and dry them at 120 °C to obtain pretreated glass fibers. Place a high-temperature resistant glass fiber woven base fabric (Boda fiberglass, the grammage can be 380-400 g / m 2 , the grammage in this example is 400 g / m 2) It is impregnated in a PTFE emulsion with a solid content of 40%, and then dried in a shaping oven at a temperature of 200°C at a speed of 4 m / min to obtain a pre-treated high-temperature resistant fiberglass woven base fabric.

[0035] S2. After mixing the pre-treated glass fibers and PI fibers (length 50 mm, fineness 2.0 dtex) according to a weight ratio of 85:15, a mixed fiber is obtained.

[0036] S3. The pre-treated PTFE fibers and the mixed fibers are respectively carded, formed into a web, and laid into a mat. The pre-treated PTFE fibers form the surface layer with a grammage of 130 g / m 2 . The mixed fibers form the bottom layer with a grammage of 210 g / m 2 , and the middle base fabric uses the pre-treated high-temperature resistant fiberglass woven base fabric. After pre-needling reinforcement and winding into a roll, a pre-needled felt is obtained. The pre-needled felt is subjected to hydroentangling reinforcement using five hydroentangling heads, and the pre-needled felt is successively passed through 1# 150 - 180 bar, 2# 130 - 160 bar, 3# 150 - 180 bar, 4# 130 - 160 bar, 5# 150 - 180 bar, with a hydroentangling speed of 5 m / min. After hydroentangling reinforcement, it is dried at 130°C and then wound to obtain a filter media plain felt.

[0037] S4. The filter media plain felt is impregnated in a fluorocarbon finishing agent (Jiaxing Yuxin, YX - 608) with a mass concentration of 4%. After impregnation, squeezing is carried out with a squeeze retention of 125%, and then it is dried in a shaping oven at a temperature of 200°C at a speed of 4 m / min to complete shaping. Then, a microporous PTFE film with a thickness of 9 μm and a pore size of 1.3 μm is laminated to the surface layer, and hot pressing is carried out through an electromagnetic roll with the temperature of the electromagnetic roll being 365°C. After hot pressing, lamination is completed to obtain a high-temperature resistant and corrosion-resistant composite hydroentangled filter media.

[0038] Example 2

[0039] The difference between this example and Example 1 is only that in step S2: after mixing the pre-treated glass fibers and PI fibers (length 50 mm, fineness 2.0 dtex) according to a weight ratio of 75:25, a mixed fiber is obtained.

[0040] Example 3

[0041] The difference between this example and Example 1 is only that in step S2: after mixing the pre-treated glass fibers and PI fibers (length 50 mm, fineness 2.0 dtex) according to a weight ratio of 95:5, a mixed fiber is obtained.

[0042] Example 4

[0043] The difference between this embodiment and Embodiment 1 is only that in Step S3: the pre-needled felt is hydroentangled using five hydroentangling heads, and the pre-needled felt is successively passed through 1# at 150 - 180 bar, 2# at 130 - 160 bar, 3# at 150 - 180 bar, 4# at 130 - 160 bar, 5# at 150 - 180 bar, the hydroentangling speed is 4 m / min, and after hydroentangling, it is dried at 100 °C.

[0044] Embodiment 5

[0045] The difference between this embodiment and Embodiment 1 is only that in Step S3: the pre-needled felt is hydroentangled using five hydroentangling heads, and the pre-needled felt is successively passed through 1# at 150 - 180 bar, 2# at 130 - 160 bar, 3# at 150 - 180 bar, 4# at 130 - 160 bar, 5# at 150 - 180 bar, the hydroentangling speed is 6 m / min, and after hydroentangling, it is dried at 150 °C.

[0046] Embodiment 6

[0047] The difference between this embodiment and Embodiment 1 is only that in Step S3: the grammage of the surface layer is 110 g / m 2 .

[0048] Embodiment 7

[0049] The difference between this embodiment and Embodiment 1 is only that in Step S3: the grammage of the surface layer is 120 g / m 2 .

[0050] Embodiment 8

[0051] The difference between this embodiment and Embodiment 1 is only that in Step S3: the grammage of the surface layer is 140 g / m 2 .

[0052] Embodiment 9

[0053] The difference between this embodiment and Embodiment 1 is only that in Step S3: the grammage of the surface layer is 150 g / m 2 .

[0054] Embodiment 10

[0055] The difference between this embodiment and Embodiment 1 is only that in Step S3: the grammage of the bottom layer is 190 g / m 2 .

[0056] Embodiment 11

[0057] The difference between this embodiment and Embodiment 1 is only that in Step S3: the grammage of the bottom layer is 200 g / m 2 .

[0058] Example 12

[0059] The difference between this example and Example 1 is only that in step S3: the basis weight of the bottom layer is 220 g / m 2 .

[0060] Example 13

[0061] The difference between this example and Example 1 is only that in step S3: the basis weight of the bottom layer is 230 g / m 2 .

[0062] Example 14

[0063] The difference between this example and Example 1 is only that the rolling allowance is 115%.

[0064] Example 15

[0065] The difference between this example and Example 1 is only that the rolling allowance is 130%.

[0066] Example 16

[0067] The difference between this example and Example 1 is only that in step S1, the glass fiber (silica content ≥ 55%, diameter 6 - 9 μm) is placed in a high-temperature calcination furnace, heat-treated at 420 °C for 30 minutes, cooled to room temperature, immersed in a 1.5% by mass dilute hydrochloric acid solution for ultrasonic cleaning for 10 minutes, rinsed with deionized water until neutral, and dried at 120 °C to obtain pretreated glass fiber.

[0068] Example 17

[0069] The difference between this example and Example 1 is only that in step S1, the glass fiber (silica content ≥ 55%, diameter 6 - 9 μm) is placed in a high-temperature calcination furnace, heat-treated at 480 °C for 30 minutes, cooled to room temperature, immersed in a 1.3% by mass dilute hydrochloric acid solution for ultrasonic cleaning for 10 minutes, rinsed with deionized water until neutral, and dried at 120 °C to obtain pretreated glass fiber.

[0070] Example 18

[0071] The difference between this example and Example 1 is only that in step S4, after shaping, a microporous PTFE film with a thickness of 7 μm and a pore diameter of 1 μm is laminated to the surface layer and hot-pressed by an electromagnetic roll.

[0072] Example 19

[0073] The difference between this embodiment and Embodiment 1 is only that in step S4, after shaping, a microporous PTFE film with a thickness of 10 μm and a pore diameter of 1.5 μm is laminated to the surface layer and hot-pressed by an electromagnetic roller.

[0074] Comparative example

[0075] Comparative example 1

[0076] The difference between this comparative example and Embodiment 1 is only that the preparation method of the high-temperature resistant and corrosion-resistant composite spunlace filter material adopts the following steps:

[0077] S1. Glass fibers (silica content ≥ 55%, diameter 6 - 9 μm) and PI fibers (length 50 mm, fineness 2.0 dtex) are mixed according to a weight ratio of 85:15 to obtain mixed fibers.

[0078] S2. PTFE fibers with a fineness of 1.5 - 3.0 dtex and a length of 40 - 60 mm and the mixed fibers are respectively carded, formed into a web, and laid, and the PTFE fibers form the surface layer with a grammage of 130 g / m 2 . The mixed fibers form the bottom layer with a grammage of 210 g / m 2 . The intermediate base fabric uses a high-temperature resistant glass fiber woven base fabric, which is pre-needled and reinforced, wound into a roll to obtain a pre-needled felt. The pre-needled felt is hydroentangled with five hydroentangling heads, and the pre-needled felt passes through 1# 150 - 180 bar, 2# 130 - 160 bar, 3# 150 - 180 bar, 4# 130 - 160 bar, 5# 150 - 180 bar in sequence, and the hydroentangling speed is 5 m / min. After hydroentangling, it is dried at 130 °C and then wound to obtain a filter material base felt.

[0079] S3. The filter material base felt is impregnated in a fluorocarbon compound finishing agent with a mass concentration of 4% (Jiaxing Yuxin, YX - 608). After impregnation, squeezing is carried out with a squeezing surplus of 125%, and then it is dried by passing through a setting oven at a temperature of 200 °C at a speed of 4 m / min to complete setting. Then, a microporous PTFE film with a thickness of 9 μm and a pore diameter of 1.3 μm is laminated to the surface layer and hot-pressed by an electromagnetic roller. The temperature of the electromagnetic roller is 365 °C. After hot-pressing, film coating is completed to obtain a high-temperature resistant and corrosion-resistant composite spunlace filter material.

[0080] Comparative example 2

[0081] The difference between this comparative example and Embodiment 1 is only that the preparation method of the high-temperature resistant and corrosion-resistant composite spunlace filter material adopts the following steps:

[0082] S1. Spray antistatic agent on PTFE short fibers with a fineness of 1.5 - 3.0 dtex and a length of 40 - 60 mm, and stack them at a constant temperature of 40 °C for 5 h to obtain pretreated PTFE short fibers. The antistatic agent in this example is an aqueous solution of antistatic agent 609 with a mass concentration of 10%. Immerse the high-temperature resistant fiberglass woven base fabric (Boda fiberglass, with a gram weight of 400 g / m 2 ) in a PTFE emulsion with a solid content of 40%, and then dry it in a shaping oven at a temperature of 200 °C at a speed of 4 m / min to obtain a pretreated high-temperature resistant fiberglass woven base fabric.

[0083] S2. Card, form a web, and lay the web for two groups of pretreated PTFE fibers. Use the pretreated high-temperature resistant fiberglass woven base fabric as the middle base fabric, and after pre-needling reinforcement, wind it into a roll to obtain a pre-needled felt. The pretreated PTFE fibers on one side of the pretreated high-temperature resistant fiberglass woven base fabric form the surface layer, with a gram weight of 130 g / m 2 . The pretreated PTFE fibers on the other side form the bottom layer, with a gram weight of 210 g / m 2 . Perform hydroentangling on the pre-needled felt, using five hydroentangling heads, and pass the pre-needled felt through 1# 150 - 180 bar, 2# 130 - 160 bar, 3# 150 - 180 bar, 4# 130 - 160 bar, 5# 150 - 180 bar in sequence. The hydroentangling speed is 5 m / min. After hydroentangling reinforcement, dry it at 130 °C, and then wind it to obtain a filter media base felt.

[0084] S4. Immerse the filter media base felt in a fluorocarbon compound finishing agent (Jiaxing Yuxin, YX - 608) with a mass concentration of 4%. After immersion, perform rolling, with a rolling surplus of 125%, and then dry it in a shaping oven at a temperature of 200 °C at a speed of 4 m / min to complete shaping. Then attach a microporous PTFE film with a thickness of 9 μm and a pore diameter of 1.3 μm to the surface layer, and perform hot pressing with an electromagnetic roll. The temperature of the electromagnetic roll is 365 °C. After hot pressing, complete film covering to obtain a high-temperature resistant and corrosion-resistant composite hydroentangled filter media.

[0085] Comparative Example 3

[0086] The difference between this comparative example and Example 1 lies only in the preparation method of the high-temperature resistant and corrosion-resistant composite hydroentangled filter media, which adopts the following steps:

[0087] S1. Spray antistatic agent on PTFE short fibers with a fineness of 1.5 - 3.0 dtex and a length of 40 - 60 mm, and stack them at a constant temperature of 40 °C for 5 h to obtain pretreated PTFE short fibers. The antistatic agent in this example is an aqueous solution of antistatic agent 609 with a mass concentration of 10%. Place glass fibers (silica content ≥ 55%, diameter 6 - 9 μm) in a high-temperature calcination furnace, heat-treat them at 450 °C for 30 minutes, cool them to room temperature, immerse them in a 1% dilute hydrochloric acid solution for ultrasonic cleaning for 10 minutes, rinse them with deionized water until neutral, and dry them at 120 °C to obtain pretreated glass fibers.

[0088] S2. Mix the pretreated glass fibers and PI fibers (length 50 mm, fineness 2.0 dtex) according to a weight ratio of 85:15 to obtain mixed fibers.

[0089] S3. Card, form a web, and lay the web for the pretreated PTFE fibers and the mixed fibers respectively. The pretreated PTFE fibers form the surface layer, and the mixed fibers form the bottom layer. Do not use an intermediate base fabric. The pretreated PTFE fibers form the surface layer with a gram weight of 130 g / m 2 . The mixed fibers form the bottom layer with a gram weight of 210 g / m 2 . Then wind them into a roll to obtain a pre-needled felt. Perform hydroentangling on the pre-needled felt, use five hydroentangling heads, and pass the pre-needled felt through 1# 150 - 180 bar, 2# 130 - 160 bar, 3# 150 - 180 bar, 4# 130 - 160 bar, 5# 150 - 180 bar in sequence. The hydroentangling speed is 5 m / min. After hydroentangling and drying at 130 °C, then wind it to obtain a filter media base felt.

[0090] S4. Immerse the filter media base felt in a fluorocarbon finishing agent (Jiaxing Yuxin, YX - 608) with a mass concentration of 4%. After immersion, perform squeezing, and the squeeze-remnant is 125%. Then pass it through a drying oven at a temperature of 200 °C at a speed of 4 m / min to complete the setting. Then attach a microporous PTFE film with a thickness of 9 μm and a pore diameter of 1.3 μm to the surface layer, and perform hot pressing through an electromagnetic roll. The temperature of the electromagnetic roll is 365 °C. After hot pressing, complete the film laminating to obtain a high-temperature and corrosion-resistant composite hydroentangled filter media.

[0091] Performance detection test

[0092] For Examples 1 - 19 and Comparative Examples 1 - 3, conduct the following performance detections:

[0093] According to GB / T6719 - 2009 "Technical Requirements for Bag Filters", detect the thermal shrinkage rate of the high-temperature and corrosion-resistant composite hydroentangled filter media prepared in each example and comparative example after being kept at a constant temperature of 300 °C for 24 hours.

[0094] According to ISO9073-4 "Textiles - Test methods for nonwovens - Part 4: Determination of resistance to delamination", the peel strength between the middle layer and the bottom layer of the high-temperature and corrosion-resistant composite spunlace filter materials prepared in each example and Comparative Examples 1 and 3 was detected. The peel strength between the middle layer and the base fabric of the high-temperature and corrosion-resistant composite spunlace filter material prepared in Comparative Example 2 was detected.

[0095] According to GB / T12625-1990, the dust removal rate of the high-temperature and corrosion-resistant composite spunlace filter materials prepared in each example and comparative example was detected.

[0096] The samples (50×50mm) of the high-temperature and corrosion-resistant composite spunlace filter materials prepared in each example and Comparative Examples 1 and 3 were respectively immersed in a HCl solution with a mass concentration of 10% and a NaOH solution with a mass concentration of 30% at a temperature of 25±2°C for 72 hours. After taking them out, they were rinsed and dried. Then, according to the mass loss rate = (initial mass of the sample - mass of the sample after immersion treatment) ÷ initial mass of the sample × 100%, the mass loss rate was determined.

[0097] The test results are shown in Table 1.

[0098] Table 1

[0099]

[0100]

[0101] Combining Example 1 and Comparative Examples 1-3 and referring to Table 1, it can be seen that compared with Example 1, the dust removal rate of Comparative Examples 1-3 decreased, the peel strength decreased, and the thermal shrinkage rate, mass loss rate after acid impregnation, and mass loss rate after alkali impregnation all increased. This shows that adopting the preparation method of Example 1 helps to synergistically improve the high-temperature resistance and strong corrosion resistance of the filter material, and moreover, the prepared filter material has excellent dust removal performance and mechanical properties.

[0102] Combining Examples 1-19 and referring to Table 1, it can be seen that the dust removal rates of Examples 1-19 are all above 99%, the peel strengths are all above 39 MPa, the thermal shrinkage rates are all below 2%, and the mass loss rates after acid impregnation and alkali impregnation are all below 2.0%. This shows that adopting the preparation methods within the range of Examples 1-19 all help to synergistically improve the high-temperature resistance and strong corrosion resistance of the filter material.

[0103] This specific embodiment is only an interpretation of the present application, and it does not limit the present application. Those skilled in the art can make modifications without creative contributions to this embodiment according to needs after reading this specification, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A preparation method of a high-temperature resistant and corrosion-resistant composite spunlace filter material, characterized in that, It includes the following steps: S1. Spray antistatic agent on PTFE short fibers, stack them at a constant temperature to obtain pretreated PTFE short fibers; rinse and dry glass fibers to obtain pretreated glass fibers; Immerse a high-temperature resistant glass fiber woven base fabric in PTFE emulsion and dry it to obtain a pretreated high-temperature resistant glass fiber woven base fabric; S2. Mix the pretreated glass fibers and PI fibers in a weight ratio of (75 - 95):(5 - 25) to obtain mixed fibers; S3. Card, form a web, and lay the web for the pretreated PTFE fibers and the mixed fibers respectively. The pretreated PTFE fibers form the surface layer, the mixed fibers form the bottom layer, and the intermediate base fabric uses the pretreated high-temperature resistant glass fiber woven base fabric. After pre-needling reinforcement, wind it into a roll to obtain a pre-needled felt. Carry out hydroentangling reinforcement, drying and winding on the pre-needled felt to obtain a filter media base felt; S4. Immerse the filter media base felt in a finishing agent. After the immersion ends, squeeze out the excess liquid, dry and shape it, and apply a film to obtain a high-temperature resistant and corrosion resistant composite hydroentangled filter media.

2. The preparation method of the high-temperature resistant and corrosion-resistant composite spunlace filter material according to claim 1, characterized in that, In step S3, the grammage of the surface layer is 120-140 g / m 2 .

3. The preparation method of the high-temperature resistant and corrosion-resistant composite spunlace filter material according to claim 2, characterized in that, In step S3, the basis weight of the bottom layer is 200-220 g / m 2 .

4. The preparation method of the high-temperature resistant and corrosion resistant composite spunlace filter material according to claim 3, characterized in that, In step S1, the grammage of the high-temperature resistant glass fiber woven base fabric is 380 - 400 g / m 2 .

5. The preparation method of the high-temperature resistant and corrosion-resistant composite spunlace filter material according to claim 1, characterized in that, In step S1, heat-treat the glass fibers at 420 - 480 °C, cool them to room temperature, then immerse them in a dilute hydrochloric acid solution with a mass concentration of 1 - 1.5%, and after the immersion ends, rinse and dry them to obtain pretreated glass fibers.

6. The preparation method of the high-temperature and corrosion-resistant composite spunlace filter material according to claim 1, characterized in that, In step S3, the hydroentangling reinforcement is operated according to the following process: use five hydroentangling heads, and pass the pre-needled felt through 1# 150 - 180 bar, 2# 130 - 160 bar, 3# 150 - 180 bar, 4# 130 - 160 bar, 5# 150 - 180 bar in sequence. The hydroentangling speed is 4 - 6 m / min. After hydroentangling reinforcement, the drying temperature is 100 - 150 °C.

7. The preparation method of the high-temperature and corrosion-resistant composite spunlace filter material according to claim 1, characterized in that, In step S4, the film application is operated according to the following process: bond a microporous PTFE film with a thickness of 7 - 10 μm and a pore diameter of 1 - 1.5 μm to the surface layer, and hot-press it through an electromagnetic roller. The temperature of the electromagnetic roller is 350 - 380 °C. After the hot-pressing ends, the film application is completed.

8. The preparation method of the high-temperature resistant and corrosion-resistant composite spunlace filter material according to claim 7, wherein, In step S4, the squeeze-out percentage of the squeeze-out is 115% - 130%.

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