A type of polytetrafluoroethylene fiber PTFE dust collector filter bag

Abstract

This invention discloses a polytetrafluoroethylene (PTFE) fiber dust collector filter bag, relating to the field of dust collector filter bag technology. The PTFE fiber dust collector filter bag of this invention is manufactured by the following method: a modified PTFE fiber membrane is needle-punched onto a PTFE composite base fabric to obtain the PTFE fiber dust collector filter bag; wherein, the modified PTFE fiber membrane is a PTFE fiber membrane loaded with nano-Al₂O₃ powder, and the PTFE composite base fabric is a glass fiber-nano SiO₂-PTFE composite base fabric. The PTFE fiber dust collector filter bag prepared by this invention has excellent chemical stability, resistance to acid and alkali corrosion, non-hygroscopic properties, good antioxidant properties, high and low temperature resistance, good mechanical properties, wear resistance, and flame retardancy. It also exhibits significant dust removal efficiency, wide adaptability to various environments, and a long service life.

Description

Technical Field

[0001] This invention relates to the field of dust collector filter bag technology, specifically to a polytetrafluoroethylene (PTFE) fiber dust collector filter bag. Background Technology

[0002] Baghouse dust collectors are widely used in industries such as cement, steel, chemicals, and waste incineration. They are primarily used to treat flue gas and dust emitted during industrial production or generated in the surrounding environment, effectively removing pollution and purifying the air. Existing dust collector filter bags mainly fall into two categories: woven fabric and non-woven fabric. Woven fabric is made by interlacing warp and weft yarns, resulting in a dense structure, high strength, and durability. Needle-punched fabric, on the other hand, uses the up-and-down movement of needles to entangle fibers, forming a loose, porous structure with good air permeability and filtration performance. Dust collector filter bags obtained through needle punching are more widely used.

[0003] Baghouse dust collectors primarily rely on their filter bags to filter flue gas and dust. The filter media of these bags determines their adaptability to various types of flue gas and dust, as well as their service life. Due to the complex environment in which dust is filtered, the filter media must possess properties such as corrosion resistance, high-temperature resistance, oxidation resistance, and hydrolysis resistance. The properties of fibers used in industrial filter media vary significantly. Commonly used high-temperature resistant filter materials include polyphenylene sulfide (PPS) fiber needle-punched felt, polyimide (P84) fiber needle-punched felt, polytetrafluoroethylene (PTFE) fiber needle-punched felt, and glass fiber filter media. Polytetrafluoroethylene (PTFE) fiber possesses unparalleled advantages over other high-temperature resistant fibers, exhibiting resistance to high temperatures, acids, alkalis, and oxidation, and is non-hydrolyzable. This makes it highly suitable for treating various flues and dust. However, PTFE, often referred to as the "king of plastics," is a completely symmetrical, unbranched linear polymer with a unique fluorine-enclosed double-helix structure. This structure leads to difficulties in processing and molding, poor mechanical properties, a large coefficient of expansion, poor thermal conductivity, and poor wear resistance. Consequently, its dust retention and filtration performance in dust collector filter bags is limited. Therefore, existing PTFE dust collector filter bags suffer from low mechanical strength, poor wear resistance, and short service life, severely restricting the application of this technology. Summary of the Invention

[0004] The purpose of this invention is to provide a polytetrafluoroethylene (PTFE) fiber dust collector filter bag, which solves the following technical problems:

[0005] Existing polytetrafluoroethylene (PTFE) dust collector filter bags suffer from low mechanical strength, poor wear resistance, and short service life.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A polytetrafluoroethylene (PTFE) fiber dust collector filter bag, which is manufactured by the following method:

[0008] Modified polytetrafluoroethylene fiber membranes are needle-punched onto polytetrafluoroethylene composite base fabric to obtain polytetrafluoroethylene fiber PTFE dust removal filter bags.

[0009] The modified polytetrafluoroethylene fiber membrane is a polytetrafluoroethylene fiber membrane loaded with nano-Al2O3 powder, and the polytetrafluoroethylene composite base fabric is a glass fiber-nano SiO2-polytetrafluoroethylene composite base fabric.

[0010] As a further aspect of the present invention: the modified polytetrafluoroethylene fiber membrane is at least disposed on the side of the polytetrafluoroethylene composite base fabric closest to the dust, and the unit area weight of the polytetrafluoroethylene fiber PTFE dust collector filter bag is 400-800 g / m². 2 .

[0011] As a further aspect of the present invention, the preparation method of the polytetrafluoroethylene composite base fabric includes the following steps:

[0012] Tetraethyl orthosilicate and anhydrous ethanol were ultrasonically mixed, and ammonia and deionized water were added dropwise. After mixing evenly, the mixture was reacted for 4-6 hours. Then, γ-aminopropyltriethoxysilane coupling agent was added, and the reaction was continued for 4-6 hours to obtain an interface modifier.

[0013] The modified glass fiber is obtained by completely immersing the glass fiber in the interface modifier, allowing it to stand, washing and drying it.

[0014] The modified glass fiber is impregnated in a polytetrafluoroethylene aqueous dispersion, and after spinning, drying, baking, sintering, cooling and weaving, a polytetrafluoroethylene composite base fabric is obtained.

[0015] As a further aspect of the present invention: the ammonia water is a 25-30 wt% ammonia solution, the addition ratio of the anhydrous ethanol, the ammonia water, the deionized water, the tetraethyl orthosilicate and the γ-aminopropyltriethoxysilane coupling agent is 200 mL: 1-3 mL: 10-20 mL: 6-10 mL: 0.8-1.2 mL, and the solid content of the polytetrafluoroethylene in the polytetrafluoroethylene aqueous dispersion is 40-50%.

[0016] As a further aspect of the present invention: the mass ratio of the glass fiber to the interface modifier is 1:5-8, and the mass ratio of the modified glass fiber to the polytetrafluoroethylene aqueous dispersion is 1:5-10.

[0017] As a further aspect of the present invention, the method for preparing the modified polytetrafluoroethylene fiber membrane includes the following steps:

[0018] A polytetrafluoroethylene suspension was added dropwise to a polyvinyl alcohol aqueous solution, and the mixture was stirred in a sealed container at room temperature to obtain a spinning solution.

[0019] Nano Al2O3 powder was added to the spinning solution, stirred and allowed to stand to obtain a modified spinning solution.

[0020] The modified spinning solution is spun, dried, and sintered to obtain a modified polytetrafluoroethylene fiber membrane.

[0021] As a further aspect of the present invention: the mass fraction of polyvinyl alcohol in the polyvinyl alcohol aqueous solution is 10-20%, and the mass ratio of polyvinyl alcohol to polytetrafluoroethylene in the polytetrafluoroethylene suspension is 1:5-6.

[0022] As a further aspect of the present invention: the mass fraction of the nano-Al₂O₃ powder in the modified spinning solution is 0.5-1%.

[0023] The beneficial effects of this invention are:

[0024] This invention prepares a modified polytetrafluoroethylene (PTFE) fiber membrane loaded with nano-Al₂O₃ powder and a glass fiber-nano-SiO₂-PTFE composite base fabric. The modified PTFE fiber membrane is then bonded to the PTFE base fabric via a needle-punching process, and the resulting PTFE fiber dust collector filter bag is obtained through cutting and sewing. The PTFE base fabric prepared in this invention exhibits excellent mechanical properties, is pressure-resistant and wear-resistant, and the modified PTFE fiber membrane enhances the hydrophobic and oil-repellent properties of PTFE. The resulting dust collector filter bag possesses excellent chemical stability, resistance to acid and alkali corrosion, non-hygroscopic properties, good oxidation resistance, high and low temperature resistance, good mechanical properties, antistatic properties, anti-condensation properties, tensile strength, compressive strength, folding strength, and wear resistance. Furthermore, it exhibits low gas filtration resistivity, significant dust removal efficiency, wide adaptability to various environments, good economic benefits, and a service life of over 3 years. It can be widely used in high-temperature flue gas dust filtration in industries such as steel, power generation, cement, and coal-fired boilers.

[0025] This invention employs electrospinning technology to prepare polytetrafluoroethylene (PTFE) fiber membranes, and directly loads high-hardness, crystal-stable, and high-temperature-resistant nano-Al₂O₃ particles onto the surface to obtain modified PTFE fiber membranes. A secondary rough structure is constructed on the fiber membrane, modifying its surface and resulting in membranes with excellent hydrophobic and oil-repellent properties. This invention significantly enhances the hydrophobic and oil-repellent properties of PTFE fiber membranes by loading nano-Al₂O₃ particles onto the surface while maintaining the membrane's surface morphology, while also achieving good polyvinyl alcohol removal efficiency and preserving the membrane's flexibility. Furthermore, the modified PTFE fiber membranes obtained through this method can be needle-punched onto PTFE fabric, giving the resulting dust collector filter bags oil- and water-repellent properties. The filter bag surface is not easily permeated by water or oil, solving the problems of condensation and clogging, making it suitable for high-humidity environments. Simultaneously, the low surface friction coefficient and lack of dust adhesion facilitate the removal of dust layers from the filter material surface, greatly reducing the possibility of clogging.

[0026] This invention involves impregnating and coating glass fiber with nano-silica modified by a silane coupling agent. The silane coupling agent surface treatment of the nano-silica reduces its surface energy, facilitating effective dispersion and adsorption on the glass fiber surface. This increases the surface roughness of the glass fiber, enhancing its electrostatic adsorption in a polytetrafluoroethylene (PTFE) dispersion. After sintering, hydrogen bonding and mechanical interlocking enhance the interfacial bond strength between PTFE and the modified glass fiber, resulting in a glass fiber-nano-SiO2-PTFE composite material. Spinning and weaving then produce a PTFE composite fabric, ultimately improving the mechanical properties of the PTFE composite fabric. In this invention, glass fiber possesses excellent mechanical properties, abrasion resistance, dimensional stability, and chemical corrosion resistance, while nano-silica exhibits flame retardancy and abrasion resistance. Using glass fiber and silica as fillers improves the composite material's hardness and compressive strength, while reducing shrinkage, abrasion, and production costs. The base fabric obtained by this invention does not decompose at high temperatures, does not crack at low temperatures, and basically does not deform or have missing rolls after being subjected to compression load. It has excellent dimensional stability, almost no elongation, excellent wear resistance, and flame retardancy, which greatly extends the service life of dust collector filter bags. Detailed Implementation

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Example 1: The preparation method of the modified polytetrafluoroethylene fiber membrane includes the following steps:

[0029] Weigh 5g of polyvinyl alcohol granules and dissolve them in 45g of deionized water. After standing and degassing, a transparent polyvinyl alcohol solution with a mass fraction of 10% is obtained. Then, a polytetrafluoroethylene suspension containing 30g of polytetrafluoroethylene is slowly added dropwise to the above polyvinyl alcohol solution. The mixture is sealed and stirred at room temperature for 4 hours to form a spinning solution with a polytetrafluoroethylene / polyvinyl alcohol mass ratio of 6:1.

[0030] Weigh out 0.5% nano Al2O3 powder and pour it into the above spinning solution. Stir with a magnetic stirrer for 4 hours. After stirring, let it stand for 12 hours to remove bubbles and obtain the modified spinning solution.

[0031] The modified spinning solution was spun at room temperature with the following parameters set: voltage (-2, +17) kV, injection speed 0.6 mL / h, receiving distance between the nozzle and the spinning receiving roller 15 cm, roller speed 600 r / min, and then dried in a drying oven at 60°C for 4 h. Finally, it was sintered in a muffle furnace at 330°C to obtain a modified polytetrafluoroethylene fiber membrane.

[0032] Example 2: The preparation method of the modified polytetrafluoroethylene fiber membrane includes the following steps:

[0033] Weigh 5g of polyvinyl alcohol granules and dissolve them in 45g of deionized water. After standing and degassing, a transparent polyvinyl alcohol solution with a mass fraction of 10% is obtained. Then, a polytetrafluoroethylene suspension containing 30g of polytetrafluoroethylene is slowly added dropwise to the above polyvinyl alcohol solution. The mixture is sealed and stirred at room temperature for 4 hours to form a spinning solution with a polytetrafluoroethylene / polyvinyl alcohol mass ratio of 6:1.

[0034] Weigh out 0.8% nano Al2O3 powder and pour it into the above spinning solution. Stir with a magnetic stirrer for 4 hours. After stirring, let it stand for 12 hours to remove bubbles and obtain the modified spinning solution.

[0035] The modified spinning solution was spun at room temperature with the following parameters set: voltage (-2, +17) kV, injection speed 0.6 mL / h, receiving distance between the nozzle and the spinning receiving roller 15 cm, roller speed 600 r / min, and then dried in a drying oven at 60°C for 4 h. Finally, it was sintered in a muffle furnace at 330°C to obtain a modified polytetrafluoroethylene fiber membrane.

[0036] Example 3: The preparation method of polytetrafluoroethylene composite base fabric includes the following steps:

[0037] First, 6.0 mL of tetraethyl orthosilicate and 200 mL of anhydrous ethanol were ultrasonically mixed. Then, 2.0 mL of ammonia and 20 mL of deionized water were added dropwise. After mixing evenly, the mixture was placed in a water bath at 40 °C and reacted for 5 h. Then, 0.8 mL of γ-aminopropyltriethoxysilane coupling agent was added and reacted at 60 °C to obtain an interface modifier containing amino-modified silica.

[0038] 30g of glass fiber was placed in deionized water at 90℃, left to stand for a period of time, then removed and placed in α-amylase treatment solution, and placed in a constant temperature and humidity chamber for 2 hours. After 2 hours, it was removed and washed three times. It was then dried to constant weight to obtain glass fiber after removing the sizing agent. The glass fiber after removing the sizing agent was completely immersed in the interface modifier and left to stand for 4 hours. After being removed, it was washed with anhydrous ethanol and deionized water respectively and dried to obtain modified glass fiber.

[0039] The modified glass fiber was impregnated in 200 mL of polytetrafluoroethylene aqueous dispersion with a solid content of 40%, dried at 150°C and baked at 280°C, and after multiple cycles, sintered at high temperature and rapidly cooled to obtain polytetrafluoroethylene composite material.

[0040] The above-mentioned polytetrafluoroethylene composite material is subjected to extrusion, calendering, stretching, heated stretching, heated stretching, slitting, twisting into bundles, coarse stretching and extrusion stretching, fine stretching and extrusion stretching, heated stretching, and curling, and then prepared according to the warp and weft yarn process to obtain a polytetrafluoroethylene composite base fabric with a thickness of 0.45±0.05mm.

[0041] Example 4: The preparation method of polytetrafluoroethylene composite base fabric includes the following steps:

[0042] First, 6.0 mL of tetraethyl orthosilicate and 200 mL of anhydrous ethanol were ultrasonically mixed. Then, 2.0 mL of ammonia and 20 mL of deionized water were added dropwise. After mixing evenly, the mixture was placed in a water bath at 40 °C and reacted for 5 h. Then, 0.8 mL of γ-aminopropyltriethoxysilane coupling agent was added and reacted at 60 °C to obtain an interface modifier containing amino-modified silica.

[0043] Glass fiber was placed in deionized water at 90°C and left to stand for a period of time. Then, GFF was taken out and placed in α-amylase treatment solution again. After taking it out, it was placed in a constant temperature and humidity chamber and kept for a certain period of time. The fabric was then taken out and washed repeatedly three times. Finally, it was dried to constant weight to obtain glass fiber after removing the sizing agent. The above GFF-T was completely immersed in the above interface modifier and left to stand for a period of time. After taking it out, it was washed with anhydrous ethanol and deionized water respectively and dried to obtain modified glass fiber.

[0044] 35g of glass fiber was placed in deionized water at 90℃, left to stand for a period of time, then removed and placed in α-amylase treatment solution, and placed in a constant temperature and humidity chamber for 2 hours. After 2 hours, it was removed and washed three times. It was then dried to constant weight to obtain glass fiber after removing the sizing agent. The glass fiber after removing the sizing agent was completely immersed in the interface modifier and left to stand for 4 hours. After being removed, it was washed with anhydrous ethanol and deionized water respectively and dried to obtain modified glass fiber.

[0045] The modified glass fiber was impregnated in 200 mL of polytetrafluoroethylene aqueous dispersion with a solid content of 40%, dried at 150°C and baked at 280°C, and after multiple cycles, sintered at high temperature and rapidly cooled to obtain polytetrafluoroethylene composite material.

[0046] The above-mentioned polytetrafluoroethylene composite material is subjected to extrusion, calendering, stretching, heated stretching, heated stretching, slitting, twisting into bundles, coarse stretching and extrusion stretching, fine stretching and extrusion stretching, heated stretching, and curling, and then prepared according to the warp and weft yarn process to obtain a polytetrafluoroethylene composite base fabric with a thickness of 0.45±0.05mm.

[0047] Example 5: A polytetrafluoroethylene (PTFE) fiber dust collector filter bag, manufactured by the following method:

[0048] The modified polytetrafluoroethylene (PTFE) fiber membrane prepared in Example 1 was laid on both sides of the PTFE composite base fabric prepared in Example 3. The thickness of the modified PTFE fiber membrane was 1 mm. Then, the modified PTFE fiber membrane and the PTFE composite base fabric were combined by a needle punching process with a needle punching density of 400-600 needles / cm. 2 After cutting and sewing, polytetrafluoroethylene (PTFE) fiber dust collector filter bags are obtained.

[0049] Example 6: A polytetrafluoroethylene (PTFE) fiber dust collector filter bag, manufactured by the following method:

[0050] The modified polytetrafluoroethylene (PTFE) fiber membrane prepared in Example 1 was laid on both sides of the PTFE composite base fabric prepared in Example 4. The thickness of the modified PTFE fiber membrane was 1 mm. Then, the modified PTFE fiber membrane and the PTFE composite base fabric were combined by a needle punching process with a needle punching density of 400-600 needles / cm. 2 After cutting and sewing, polytetrafluoroethylene (PTFE) fiber dust collector filter bags are obtained.

[0051] Example 7: A polytetrafluoroethylene (PTFE) fiber dust collector filter bag, manufactured by the following method:

[0052] The modified polytetrafluoroethylene (PTFE) fiber membrane prepared in Example 2 was laid on both sides of the PTFE composite base fabric prepared in Example 3. The thickness of the modified PTFE fiber membrane was 1 mm. Then, the modified PTFE fiber membrane and the PTFE composite base fabric were combined by a needle punching process with a needle punching density of 400-600 needles / cm. 2 After cutting and sewing, polytetrafluoroethylene (PTFE) fiber dust collector filter bags are obtained.

[0053] Example 8: A polytetrafluoroethylene (PTFE) fiber dust collector filter bag, manufactured by the following method:

[0054] The modified polytetrafluoroethylene (PTFE) fiber membrane prepared in Example 2 was laid on both sides of the PTFE composite base fabric prepared in Example 4. The thickness of the modified PTFE fiber membrane was 1 mm. Then, the modified PTFE fiber membrane and the PTFE composite base fabric were combined by a needle punching process with a needle punching density of 400-600 needles / cm. 2 After cutting and sewing, polytetrafluoroethylene (PTFE) fiber dust collector filter bags are obtained.

[0055] Comparative Example 1: A polytetrafluoroethylene (PTFE) fiber dust collector filter bag, manufactured by the following method:

[0056] The preparation steps of the polytetrafluoroethylene (PTFE) composite base fabric are omitted. The modified PTFE fiber membrane prepared in Example 1 is laid on both sides of a commercially available glass fiber base fabric with a thickness of 1 mm. Then, the modified PTFE fiber membrane and the PTFE composite base fabric are bonded together by a needle punching process with a needle punching density of 400-600 needles / cm. 2 After cutting and sewing, polytetrafluoroethylene (PTFE) fiber dust collector filter bags are obtained.

[0057] Comparative Example 2: A polytetrafluoroethylene (PTFE) fiber dust collector filter bag, manufactured by the following method:

[0058] The preparation steps of the modified polytetrafluoroethylene fiber membrane are omitted. The polytetrafluoroethylene composite base fabric prepared in Example 3 is cut and sewn to obtain a polytetrafluoroethylene fiber PTFE dust collector filter bag.

[0059] The preparation method of the polytetrafluoroethylene composite base fabric in Comparative Example 3 includes the following steps:

[0060] 30g of glass fiber was impregnated in 200mL of polytetrafluoroethylene aqueous dispersion with a solid content of 40%. After drying at 150℃ and baking at 280℃, the mixture was sintered at high temperature and rapidly cooled to obtain polytetrafluoroethylene composite material.

[0061] The above-mentioned polytetrafluoroethylene composite material is subjected to extrusion, calendering, stretching, heated stretching, heated stretching, slitting, twisting into bundles, coarse stretching and extrusion stretching, fine stretching and extrusion stretching, heated stretching, and curling, and then polytetrafluoroethylene composite base fabric is prepared according to the warp and weft yarn process.

[0062] A polytetrafluoroethylene (PTFE) fiber dust collector filter bag is manufactured by the following method:

[0063] The modified polytetrafluoroethylene (PTFE) fiber membrane prepared in Example 1 was laid on both sides of the PTFE composite base fabric prepared in this comparative example. The thickness of the modified PTFE fiber membrane was 1 mm. Then, the modified PTFE fiber membrane and the PTFE composite base fabric were combined by a needle punching process with a needle punching density of 400-600 needles / cm. 2 After cutting and sewing, polytetrafluoroethylene (PTFE) fiber dust collector filter bags are obtained.

[0064] Comparative Example 4: A polytetrafluoroethylene (PTFE) fiber dust collector filter bag, manufactured by the following method:

[0065] The modified polytetrafluoroethylene (PTFE) fiber membrane prepared in Example 1 was laid on both sides of a commercially available PTFE fabric. The thickness of the PTFE fiber membrane was 1 mm. Then, the modified PTFE fiber membrane and the PTFE composite base fabric were bonded together by a needle-punching process with a needle-punching density of 400-600 needles / cm. 2 After cutting and sewing, polytetrafluoroethylene (PTFE) fiber dust collector filter bags are obtained.

[0066] Performance testing

[0067] Contact angle: The static contact angle of the polytetrafluoroethylene fiber PTFE dust collector filter bags obtained in Examples 5-8 and Comparative Examples 1-4 was measured using a DSA30 contact angle measuring instrument manufactured by Krüger GmbH, Germany. The test results are shown in Table 1.

[0068] Flame retardancy: According to GB / T14656-2009 standard, the polytetrafluoroethylene fiber PTFE dust collector filter bags obtained in Examples 5-8 and Comparative Examples 1-4 were subjected to vertical combustion tests, and the test results are shown in Table 1.

[0069] Friction resistance: The friction and wear properties of the polytetrafluoroethylene fiber PTFE dust collector filter bags obtained in Examples 5-8 and Comparative Examples 1-4 were determined on an MM-200 friction and wear tester in accordance with GB / 3960-83 standard. The test results are shown in Table 1.

[0070] Filtration efficiency: The filtration efficiency and service life of the polytetrafluoroethylene fiber PTFE dust collector filter bags obtained in Examples 5-8 and Comparative Examples 1-4 were tested according to HJ / T324-2006 standard. The test results are shown in Table 1.

[0071] Mechanical properties: The mechanical properties of the polytetrafluoroethylene fiber PTFE dust collector filter bags obtained in Examples 5-8 and Comparative Examples 1-4 were tested using an Instron-3369 universal testing machine in accordance with GB / T 7689.5 standard. The test results are shown in Table 1.

[0072] Table 1: Statistical Table of Dust Collector Filter Bag Performance Test Data for Examples 5-8 and Comparative Examples 1-4

[0073]

[0074]

[0075] As shown in Table 1, the polytetrafluoroethylene fiber (PTFE) dust collector filter bags prepared in Examples 5-8 and Comparative Examples 1-4 of the present invention have good hydrophobicity, oil repellency, flame retardancy, and abrasion resistance, as well as good mechanical properties, long service life, and significant dust removal efficiency, which can reach up to 99%, greatly exceeding the national standard and approaching zero emissions. In Comparative Example 1, modified polytetrafluoroethylene (PTFE) fibers were needle-punched onto both sides of a commercially available glass fiber base fabric, and then cut and sewn to form a dust collector filter bag. The resulting dust collector filter bag exhibited reduced abrasion resistance and mechanical properties, as well as significantly reduced filtration efficiency and service life. In Comparative Example 2, PTFE composite base fabric was directly cut and sewn to form a dust collector filter bag. The resulting dust collector filter bag exhibited reduced hydrophobicity and abrasion resistance, and also reduced dust removal efficiency. In Comparative Example 3, the glass fiber was not modified, resulting in a dust collector filter bag with poor flame retardancy and reduced mechanical properties. In Comparative Example 4, modified PTFE fibers were needle-punched onto both sides of a commercially available PTFE vinyl ester fabric, and then cut and sewn to form a dust collector filter bag. The resulting dust collector filter bag exhibited significantly reduced abrasion resistance, flame retardancy, and mechanical properties.

[0076] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A method for preparing a polytetrafluoroethylene (PTFE) fiber dust collector filter bag, characterized in that, It includes at least the following preparation steps: Modified polytetrafluoroethylene fiber membranes are needle-punched onto polytetrafluoroethylene composite base fabric to obtain polytetrafluoroethylene fiber PTFE dust removal filter bags. The preparation method of the polytetrafluoroethylene composite base fabric includes the following steps: Tetraethyl orthosilicate and anhydrous ethanol were ultrasonically mixed, and ammonia and deionized water were added dropwise. After mixing evenly, the mixture was reacted for 4-6 hours. Then, γ-aminopropyltriethoxysilane coupling agent was added, and the reaction was continued for 4-6 hours to obtain an interface modifier. The modified glass fiber is obtained by completely immersing the glass fiber in the interface modifier, allowing it to stand, washing and drying it. The modified glass fiber was impregnated in a polytetrafluoroethylene aqueous dispersion, and after spinning, drying, baking, sintering, cooling and weaving, a polytetrafluoroethylene composite base fabric was obtained. The preparation method of the modified polytetrafluoroethylene fiber membrane includes the following steps: A polytetrafluoroethylene suspension was added dropwise to a polyvinyl alcohol aqueous solution, and the mixture was stirred in a sealed container at room temperature to obtain a spinning solution. Nano Al2O3 powder was added to the spinning solution, stirred and allowed to stand to obtain a modified spinning solution. The modified spinning solution is spun, dried, and sintered to obtain a modified polytetrafluoroethylene fiber membrane.

2. The method for preparing a polytetrafluoroethylene (PTFE) fiber dust collector filter bag according to claim 1, characterized in that, The modified polytetrafluoroethylene (PTFE) fiber membrane is disposed at least on the side of the PTFE composite base fabric closest to the dust, and the PTFE fiber dust collector filter bag has a unit area weight of 400-800 g / m². 2 .

3. The method for preparing a polytetrafluoroethylene (PTFE) fiber dust collector filter bag according to claim 1, characterized in that, The ammonia water is a 25-30 wt% ammonia solution, and the addition ratio of the anhydrous ethanol, the ammonia water, the deionized water, the tetraethyl orthosilicate and the γ-aminopropyltriethoxysilane coupling agent is 200 mL: 1-3 mL: 10-20 mL: 6-10 mL: 0.8-1.2 mL. The solid content of polytetrafluoroethylene in the polytetrafluoroethylene aqueous dispersion is 40-50%.

4. The method for preparing a polytetrafluoroethylene (PTFE) fiber dust collector filter bag according to claim 1, characterized in that, The mass ratio of the glass fiber to the interface modifier is 1:5-8, and the mass ratio of the modified glass fiber to the polytetrafluoroethylene aqueous dispersion is 1:5-10.

5. The method for preparing a polytetrafluoroethylene (PTFE) fiber dust collector filter bag according to claim 1, characterized in that, The polyvinyl alcohol aqueous solution contains 10-20% polyvinyl alcohol by mass, and the mass ratio of polyvinyl alcohol to polytetrafluoroethylene in the polytetrafluoroethylene suspension is 1:5-6.

6. The method for preparing a polytetrafluoroethylene (PTFE) fiber dust collector filter bag according to claim 1, characterized in that, The mass fraction of the nano-Al2O3 powder in the modified spinning solution is 0.5-1%.

7. A polytetrafluoroethylene (PTFE) fiber dust collector filter bag, characterized in that, It is prepared by the preparation method described in any one of claims 1-6.

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