High-temperature-resistant anti-stripping PTFE (Polytetrafluoroethylene) membrane filter layer, preparation method and dust removal filter bag

Abstract

The invention relates to the technical field of industrial dust removal, in particular to a high-temperature-resistant anti-stripping PTFE (polytetrafluoroethylene) membrane filter layer, a preparation method and a dust removal filter bag, the high-temperature-resistant anti-stripping PTFE membrane filter layer comprises a PTFE membrane layer, the PTFE membrane layer comprises a micropore area and a plurality of closed-pore areas, the micropore area of the PTFE membrane layer is provided with a plurality of micropores penetrating through the PTFE membrane layer, and the closed-pore areas of the PTFE membrane layer are communicated with the micropore area; the closed pore area of the PTFE film layer does not contain the micropores or the porosity is less than 5%; the base layer comprises a first thickness layer and a plurality of convex structures which extend from the surface of the first thickness layer to the second thickness layer along the thickness direction of the first thickness layer. According to the invention, the closed-pore area is arranged on the PTFE film layer and the convex structure is arranged on the base layer, when the PTFE film layer and the base layer are compounded, the convex structure of the base material is combined with the closed-pore area of the PTFE film layer, and molecular chains of the PTFE and the base material are entangled by hot-pressing and melting, so that chemical bonding force is generated, and the interface bonding strength is enhanced; particularly, the layering resistance is obviously enhanced under a high-temperature vibration working condition, and the service life of the filter bag structure is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial dust removal, and particularly relates to a high-temperature resistant and anti-detachment PTFE film-covered filter layer, a preparation method thereof, and a dust removal filter bag. Background Art

[0002] The filter media of traditional bag filters are generally made of woven filter cloth or non-woven needle felt. Its dust removal mechanism is the "deep filtration" technology, that is, in the initial stage of filtration, a dust cake is first formed on the surface of the filter bag through the capture of dust by the filter media fibers, and then this dust cake is used as the main filter layer to filter the dust. The disadvantage of this method is that due to the relatively large pores in the filter media itself, some dust will pass through the filter media and be discharged in the initial stage of filtration, resulting in poor initial filtration effect.

[0003] Polytetrafluoroethylene (PTFE) film-covered dust removal filter bags have the advantages of high temperature resistance, chemical corrosion resistance, high filtration efficiency, anti-frosting and anti-blocking, so dust removal filter bags based on PTFE film are widely used in dust removal fields such as waste incineration and coal-fired power plants.

[0004] PTFE forms a microporous film through a biaxial stretching process and is compounded with a substrate through a hot lamination process to form a surface filtration structure. The PTFE film-covered dust removal filter bag can be installed in a bag filter. When the flue gas passes through the filter bag, the dust is intercepted on the surface of the film, and the clean gas passes through the filter bag and is discharged.

[0005] Among them, the PTFE film has a three-dimensional network microporous structure, a smooth and hydrophobic surface. The dust is intercepted on the surface of the film rather than penetrating into the interior of the substrate, realizing "surface filtration". The substrate provides mechanical support and temperature resistance for the microporous film. Common substrates include polyester, PPS, P84, etc., which can withstand high temperatures below 260°C.

[0006] When the traditional PTFE microporous film and the substrate are hot-pressed and compounded, if the upper limit of the hot-pressing temperature is low, the connection at the composite interface is not firm, and it is easy to delaminate under high temperature or mechanical vibration. If the hot-pressing temperature is increased, the micropores will collapse, affecting the filtration efficiency. In the prior art, attempts have been made to increase the interface strength by adding adhesives, but the adhesive will penetrate into the micropores, resulting in a decrease in air permeability and poor high-temperature resistance.

[0007] Therefore, there is an urgent need for a dust removal filter bag structure that takes into account interface strength, filtration efficiency and high temperature resistance. Summary of the Invention

[0008] In view of the technical problems existing in the PTFE film-covered filter layer in the prior art, the first aspect of the present invention proposes a high-temperature resistant and anti-detachment PTFE film-covered filter layer, including:

[0009] The PTFE film layer includes a microporous region and a plurality of closed pore regions. The PTFE film layer has a plurality of micropores penetrating the PTFE film layer in the microporous region, and the closed pore regions of the PTFE film layer do not contain the micropores or have a porosity of less than 5%.

[0010] The base layer includes a first thickness layer and a plurality of raised structures extending from the surface of the first thickness layer along its thickness direction to a second thickness layer. The base layer includes a woven fiber cloth substrate or a non-woven fiber cloth substrate.

[0011] Among them, a plurality of the closed pore regions are regularly distributed in the PTFE film layer, and adjacent closed pore regions do not contact each other. The PTFE film layer and the base layer are fixed to each other, and the raised structures of the base layer correspond to the closed pore regions of the PTFE film layer in position and are in contact with each other.

[0012] Preferably, the closed pore regions in the PTFE film layer account for 10-20% of the total area of the PTFE film layer.

[0013] Preferably, the diameter of the closed pore regions is 0.5-1 mm, the distance between adjacent closed pore regions is 1-3 mm, and a plurality of the closed pore regions are distributed in a matrix array or a honeycomb shape.

[0014] Preferably, the raised height of the raised structures is 0.1-0.3 mm, and the raised structures are arranged such that the cross-sectional diameter near the first thickness layer is larger than the cross-sectional diameter near the second thickness layer.

[0015] Preferably, the surface of the raised structures is provided with a polyphenylene sulfide or polyimide adhesive layer, and the thickness of the adhesive layer is 5-15 microns.

[0016] Preferably, the contact interface between the raised structures and the closed pore regions forms a molten bonding layer through hot pressing.

[0017] Preferably, a gradient transition zone is provided around the microporous region. In the gradient transition zone, the micropores are arranged with a gradually changing pore diameter, which gradually increases from 0 to 0.5 microns according to the distance from the center of the microporous region.

[0018] In a second aspect of the present invention, a method for preparing the above-mentioned high-temperature resistant and anti-detachment PTFE-coated filter layer is proposed, including the following steps:

[0019] Step 1, PTFE film layer processing: The PTFE film layer is subjected to biaxial stretching to form a microporous film, and micropores in a predetermined region of the PTFE film layer are closed by laser selective sintering or femtosecond laser to form a plurality of closed pore regions.

[0020] Step 2, base layer processing: A plurality of raised structures are formed on the surface of the base layer by hot embossing.

[0021] Step 3, film layer lamination: Align the convex structure of the base layer with the closed-cell area of the PTFE film layer, and perform hot pressing at 350 - 380 °C and a pressure of 0.8 - 1.5 MPa for 10 - 15 seconds to achieve interfacial melt bonding.

[0022] Preferably, if the base layer is a woven fiber cloth, multiple convex structures are formed by pressing with a hot pressing mold at 300 - 400 °C and a pressure of 5 - 10 MPa; if the base layer is a non-woven fiber cloth, multiple convex structures are formed by an ultrasonic embossing process at a frequency of 20 - 40 kHz and a linear pressure of 100 - 150 N / cm.

[0023] The third aspect of the present invention proposes a dust removal filter bag, including:

[0024] A support structure, including a support cage and a connection structure;

[0025] A bag body, including an opening, the bag body is sleeved outside the support cage, and the opening extends and is fixed to the outside of the connection structure;

[0026] Wherein, the bag body is made of the above-mentioned high-temperature resistant and anti-detachment PTFE coated filter layer;

[0027] The bag body is arranged to fit the surface of the support cage, and the bag body is arranged as a cylindrical bag body or a columnar bag body with pleats on the side wall.

[0028] Compared with the prior art, the advantages of the present invention are as follows:

[0029] By setting a closed-cell area on the PTFE film layer and a convex structure on the base layer, when the PTFE film layer and the base layer are laminated, the convex structure of the base material is combined with the closed-cell area of the PTFE film layer. Through hot pressing, the molecular chains of PTFE and the base material are entangled, generating chemical bonding force, enhancing the interfacial bonding strength, especially significantly enhancing the anti-delamination ability under high-temperature vibration conditions, and extending the service life of the filter bag structure. Description of the Drawings

[0030] The drawings are not intended to be drawn to scale. In the drawings, each identical or approximately identical component shown in each figure may be represented by the same reference numeral. For clarity, not every component is labeled in each figure. Now, embodiments of various aspects of the present invention will be described by way of examples and with reference to the drawings, wherein:

[0031] Figure 1 is a schematic structural diagram of the high-temperature resistant and anti-detachment PTFE coated filter layer shown in the present invention;

[0032] Figure 2 is a schematic structural diagram of the PTFE film layer shown in the present invention;

[0033] Figure 3 is a schematic structural view of the base layer shown in the present invention;

[0034] Figure 4 is another schematic structural view of the high-temperature resistant and anti-detachment PTFE coated filter layer shown in the present invention;

[0035] Figure 5 is a schematic view of forming a closed pore region by treating the PTFE film layer shown in the present invention;

[0036] Figure 6 is a schematic view of forming a plurality of convex structures by treating the base layer shown in the present invention;

[0037] Figure 7 is a schematic structural view of the cylindrical dust removal filter bag shown in the present invention;

[0038] Figure 8 is a schematic cross-sectional structural view of the cylindrical dust removal filter bag shown in the present invention;

[0039] Figure 9 is a schematic structural view of the corrugated columnar dust removal filter bag shown in the present invention;

[0040] Figure 10 is a schematic cross-sectional structural view of the corrugated columnar dust removal filter bag shown in the present invention. Detailed Embodiments

[0041] In order to better understand the technical content of the present invention, specific embodiments are hereby given and described in conjunction with the accompanying drawings as follows.

[0042] In the prior art, there is a contradiction between the interfacial bonding strength and the structural integrity in the hot pressing and compounding between the PTFE film layer and the base layer. For example, under high temperature and high pressure (especially when approaching the melting point of PTFE, 327 °C), plastic deformation is likely to occur in the contact area of the microporous membrane, the pore diameter increases or even closes, resulting in a decrease in filtration efficiency. When hot pressing evenly, the contact surface between the membrane and the substrate only relies on physical adsorption, and the bonding strength is usually lower than 0.5 MPa, and delamination is likely to occur under dynamic working conditions.

[0043] At the same time, when using an adhesive for auxiliary compounding, there is a contradiction between the air permeability and the bonding strength. The used adhesive will penetrate into the micropores. For example, when the viscosity of the polyurethane adhesive is ≤200 cP, the penetration depth can reach 50 μm, resulting in a decrease in the air permeability by more than 30%. At the same time, the adhesive is also easily decomposed at high temperatures and cannot meet the requirement of high temperature resistance.

[0044] Therefore, based on the above composite problem of the PTFE film layer and the base layer, the present application aims to construct microporous regions and closed pore regions in the PTFE film layer, and construct raised structures on the base layer, so that the closed pore regions of the PTFE film layer are combined with the raised structures on the base layer, and the combination region is transferred from the porous weak region to the non-porous high-strength region, which can significantly improve the interface strength, while also ensuring the filtration efficiency and reducing the pore loss.

[0045]

High-temperature resistant and anti - detachment PTFE coated filter layer

[0046] Combination Figures 1 to 3 As shown in the figure, a first aspect of the present invention proposes a high-temperature resistant and anti - detachment PTFE coated filter layer, which includes a PTFE film layer 10 and a base layer 20.

[0047] In an optional embodiment, the thickness of the PTFE film layer 10 is 20 - 50 microns, and the thickness of the base layer 20 is 0.5 - 3 mm.

[0048] Among them, the PTFE film layer 10 includes a microporous region 11 and a plurality of closed pore regions 12. The PTFE film layer 10 has a plurality of micropores penetrating the PTFE film layer 10 in the microporous region 11.

[0049] In an optional embodiment, as Figure 4 shown, first, a thick substrate is formed by pre - pressing a PTFE dispersion resin + 30% glass fiber reinforcing agent through an extruder in step a1, and then the thick substrate is formed into a microporous membrane through a biaxial stretching step a2. The micropore diameter of the microporous region 11 is 0.2 - 0.5 microns. After the PTFE film layer 10 is stretched to form a microporous membrane, steps a3 such as femtosecond laser or selective laser sintering for constructing closed pore regions can be used to close the micropores on the surface of the microporous membrane by the heat melting generated by the laser to form closed pore regions.

[0050] If the porosity in the closed pore region 12 is too high, it will cause low bonding interface strength. Therefore, optionally, the closed pore region 12 of the PTFE film layer 10 does not contain micropores or the porosity is less than 5%.

[0051] Furthermore, the base layer 20 includes a first thickness layer 22 and a plurality of raised structures 21 extending from the surface of the first thickness layer 22 along its thickness direction to the second thickness layer.

[0052] Among them, the base layer 20 can be selected as a woven fiber cloth substrate or a non - woven fiber cloth substrate.

[0053] The woven fiber cloth substrate can be selected as a glass fiber cloth, and protrusions can be formed by hot pressing. For example, hemispherical pits are etched on the surface of a stainless steel pressing roller. The size of the pits can be selected as a diameter of 1 mm and a depth of 0.3 mm, arranged in a hexagonal or matrix close-packed pattern. During hot pressing, the temperature of the pressing roller is controlled at 380 °C, the pressure is 8 MPa, and the contact time is 5 s to form regular protrusions with a height of 0.25 mm.

[0054] Preferably, after forming the regular protrusions, a PTFE suspension (concentration 20%) is sprayed and sintered at a temperature of 350 °C to form an anti-corrosion coating.

[0055] The non-woven fiber cloth substrate can be selected as an aramid non-woven fabric, and a protrusion structure is formed by ultrasonic embossing. For example, a 20 kHz ultrasonic generator + a titanium alloy embossing roller is used. Among them, the pattern of the titanium alloy embossing roller is configured to correspond to the closed pore region 12. At an amplitude of 50 μm, a linear pressure of 120 N / cm, and a speed of 1.5 m / min, local melting of the fibers is caused by frictional heat to form a protrusion structure 21.

[0056] Preferably, after forming the protrusion structure 21, it is impregnated with a 5% polyimide solution and cured at a temperature of 250 °C, so as to improve the stability of the protrusion structure 21.

[0057] In this way, through the provided protrusion structure 21, when the PTFE film layer 10 and the base layer 20 are hot-pressed and compounded, the protrusion structure 21 and the closed pore region 12 come into contact and melt and bond with each other. While meeting the composite strength, it can avoid closing other micropores and maintain a good porosity.

[0058] As described above, the contact interface between the protrusion structure 21 and the closed pore region 12 forms a molten-bonded bonding layer through hot pressing, and this bonding layer has a more reliable connection ability.

[0059] In an alternative embodiment, multiple closed pore regions 12 are regularly distributed on the PTFE film layer 10, and the adjacent closed pore regions 12 do not contact each other. The PTFE film layer 10 and the base layer 20 are fixed to each other, and the protrusion structure 21 of the base layer 20 corresponds to the closed pore region 12 of the PTFE film layer 10 and comes into contact with each other.

[0060] In this way, the protrusion structure 21 and the closed pore region 12 of the PTFE film layer 10 form a bonding interface layer, which can inhibit the propagation of cracks. Especially when applied to the dust removal filter bag of a bag filter, it can reduce the risk of film coating and substrate dust under cyclic load factors. Therefore, while improving the interface strength, the filtration performance is maintained.

[0061] In the above embodiment, in order to maintain the air permeability of the PTFE film layer 10, the closed pore regions 12 in the PTFE film layer 10 account for 10-20% of the total area of the PTFE film layer 10.

[0062] When the proportion of the closed - cell region 12 in the PTFE film layer 10 exceeds 20%, the air - permeability decreases, which is not conducive to achieving a good filtration effect. When the proportion of the closed - cell region 12 in the PTFE film layer 10 is less than 10%, the distribution of the closed - cell region 12 is less, the load - bearing capacity increases, which is not conducive to maintaining durability and reliability.

[0063] In an alternative embodiment, the diameter of the closed - cell region 12 is 0.5 - 1 mm, the distance between adjacent closed - cell regions 12 is 1 - 3 mm, and a plurality of closed - cell regions 12 are distributed in a matrix array or honeycomb pattern. The protrusion height of the protrusion structure 21 is 0.1 - 0.3 mm, and the cross - sectional diameter of the protrusion structure 21 near the first thickness layer 22 is set to be larger than the cross - sectional diameter near the second thickness layer.

[0064] In a preferred embodiment, the surface of the protrusion structure 21 is provided with a polyphenylene sulfide or polyimide adhesive layer, and the thickness of the adhesive layer is 5 - 15 microns.

[0065] Specifically, a 10 - μm - thick polyphenylene sulfide (PPS) adhesive layer is pre - coated on the surface of the substrate protrusion. When hot - pressed, an interpenetrating network structure is formed with PTFE, which can further improve the peel strength.

[0066] Preferably, a gradient transition zone is provided around the microporous region 11. In the gradient transition zone, the micropores are set to have a gradually changing pore diameter, which gradually increases from 0 to 0.5 microns according to the distance from the center of the microporous region 11.

[0067] In this way, the possible stress concentration around the closed - cell region 12 in the later stage can be reduced, and the tearing at the junction of the closed - cell region 12 and the microporous region 11 can be avoided.

[0068]

Preparation Method of High - Temperature - Resistant and Anti - Detachment PTFE Coated Filter Layer

[0069] Combined with Figure 5 and Figure 6 As shown, a second aspect of the present invention proposes a preparation method of the above - mentioned high - temperature - resistant and anti - detachment PTFE coated filter layer, including the following steps:

[0070] Step 1, PTFE film layer 10 processing: The PTFE film layer 10 is subjected to biaxial stretching to form a microporous film, and the micropores in a predetermined area of the PTFE film layer 10 are closed by laser - selected sintering or femtosecond laser to form a plurality of closed - cell regions 12;

[0071] Step 2, base layer 20 processing: A plurality of protrusion structures 21 are formed on the surface of the base layer 20 by hot - embossing in step b1;

[0072] Step 3. Membrane layer compounding: Align the convex structure 21 of the base layer 20 with the closed-cell region 12 of the PTFE membrane layer 10, and perform hot pressing at 350 - 380 °C under a pressure of 0.8 - 1.5 MPa for 10 - 15 seconds to achieve interfacial melting and bonding.

[0073] As Figure 4 shown, first, a thick substrate is formed by pre-pressing a PTFE dispersion resin (particle size 0.2 μm) + 30% glass fiber reinforcing agent through an extruder in step a1. Then, the thick substrate is formed into a microporous membrane through a biaxial stretching step a2. During the stretching process, the longitudinal stretching ratio is 3:1 (temperature 280 °C), and the transverse stretching ratio is 4:1 (temperature 300 °C). After stretching, the micropore diameter of the microporous region 11 is 0.2 - 0.5 microns. After the PTFE membrane layer 10 is stretched to form a microporous membrane, step a3 such as femtosecond laser or selective laser sintering can be used to construct the closed-cell region, and the micropores on the surface of the microporous membrane are closed by heat melting generated by the laser to form a closed-cell region.

[0074] Among them, PTFE has no linear absorption for near-infrared femtosecond lasers (such as 1030 - 1064 nm), but through a multi-photon process, it can cause material decomposition in the focal region. The high peak power of the femtosecond laser (≥104 W / cm 2 ) causes local PTFE molecular chains to melt and recombine to form a dense pore-free structure, while the surrounding area retains micropores because the energy does not reach the threshold.

[0075] In a specific embodiment, the surface of the PTFE membrane is pre-treated by wiping with alcohol + plasma treatment to remove contaminants and improve the laser absorption rate; then, the laser scanning path is planned and controlled according to the design requirements; the PTFE membrane layer is processed in layers: The first layer: The laser focus is placed on the membrane surface, the energy is 10 μJ, the scanning speed is 200 mm / s, the repetition frequency is 200 kHz, and the spot diameter is 10 μm; For subsequent layers: Each layer is moved down 1 μm, and the scanning is repeated 3 - 5 times until the membrane thickness is penetrated; Finally, nitrogen is used to blow away the processing residues, and then low-temperature annealing is performed at 150 - 200 °C for 10 minutes to eliminate internal stress and stabilize the dense structure.

[0076] In an alternative embodiment, the closed-cell region of the microporous membrane can also be formed by selective laser sintering. Specifically, a CO2 laser is used, and the parameters are adjusted to a wavelength of 10.6 μm and a power of 50 W. The micropores on the surface of the microporous membrane are closed according to a predetermined pattern to form pore-free dots with a predetermined diameter. Among them, the scanning speed of the CO2 laser is 200 mm / s, the spot diameter is 0.5 mm, and the energy density is 15 J / cm 2 .

[0077] Further, if the base layer 20 is a woven fiber cloth, multiple convex structures 21 are formed by hot pressing with a hot pressing die at 300-400 °C and a pressure of 5-10 MPa; if the base layer 20 is a non-woven fiber cloth, multiple convex structures 21 are formed by an ultrasonic embossing process at a frequency of 20-40 kHz and a linear pressure of 100-150 N / cm.

[0078] In a specific embodiment, the woven fiber cloth substrate can be selected as a glass fiber cloth, and convexities can be formed by hot pressing. For example, hemispherical pits are etched on the surface of a stainless steel pressing roller, the size of the pits can be selected as a diameter of 1 mm and a depth of 0.3 mm, arranged in a hexagonal or matrix close-packed pattern. During hot pressing, the temperature of the pressing roller is controlled at 380 °C, the pressure is 8 MPa, and the contact time is 5 s to form regular convexities with a height of 0.25 mm.

[0079] Preferably, after forming the regular convexities, a PTFE suspension (concentration 20%) is sprayed and sintered at a temperature of 350 °C to form an anti-corrosion coating.

[0080] In a specific embodiment, the non-woven fiber cloth substrate can be selected as an aramid non-woven fabric, and convex structures are formed by ultrasonic embossing. For example, a 20 kHz ultrasonic generator + a titanium alloy embossing roller is used. Among them, the pattern of the titanium alloy embossing roller is configured to correspond to the closed pore region 12. At an amplitude of 50 μm, a linear pressure of 120 N / cm, and a speed of 1.5 m / min, the fibers are locally melted by frictional heat to form the convex structure 21.

[0081] Preferably, after forming the convex structure 21, it is impregnated with a 5% polyimide solution and cured at a temperature of 250 °C, so as to improve the stability of the convex structure 21.

[0082] Further, when the convex structure 21 of the base layer 20 is aligned and compounded with the closed pore region 12 of the PTFE film layer 10, a CCD vision system is used for alignment to ensure that the convex structure 21 coincides with the closed pore region 12, and the accuracy reaches ±0.05 mm. The hot pressing parameters can be selected as: temperature 370 °C, pressure 1.2 MPa, time 12 s, so that the PTFE melt in the closed pore region 12 forms a chemical bond with the convex structure 21.

[0083]

Dust removal filter bag

[0084] Combined Figures 7 to 10 As shown, a dust removal filter bag is proposed in the third aspect of the present invention, including:

[0085] A support structure, including a support cage and a connection structure 210;

[0086] A bag body 100, including an opening, the bag body 100 is sleeved outside the support cage, and the opening extends and is fixed to the outside of the connection structure 210;

[0087] Among them, the bag body 100 is made of the above-mentioned high-temperature resistant and anti-detachment PTFE coated filter layer;

[0088] The bag body 100 is arranged to fit the surface of the support cage, and the bag body 100 is arranged as a cylindrical bag body or a columnar bag body with pleats on the side wall.

[0089] Specifically, in combination with Figure 7 and Figure 8 As shown, the support structure includes a first support cage 200a and a connection structure 210. The first support cage 200a is composed of two upper and lower annular structures and multiple support columns 201. A support net 202 is provided on the outer wall of the multiple support columns 201, and the bag body 100 is wrapped outside the support net  202. Among them, the bag body 100 includes a first strengthening area 103 at the bottom of the first support cage 200a and a second strengthening area 102 at the top. Between the first strengthening area 103 and the second strengthening area 102 at the top is an ordinary filtering area 101.

[0090] Optionally, the filtering area 101 is made of the above-mentioned high-temperature resistant and anti-detachment PTFE coated filter layer. For the first strengthening area 103 and the second strengthening area 102 at the top, on the basis of the high-temperature resistant and anti-detachment PTFE coated filter layer, in combination with Figure 4 As shown, a strengthening layer is provided on one side of the PTFE film layer 10 and / or the base layer 20, such as an outer strengthening layer 30a or an inner strengthening layer 30b.

[0091] In an alternative embodiment, the outer strengthening layer 30a or the inner strengthening layer  30b is made of an aramid woven layer. The weaving density of the aramid woven layer of the inner strengthening layer 30b is much lower than the porosity of the base layer 20, and the porosity of the outer strengthening layer 30a is much lower than the porosity of the inner strengthening layer 30b, aiming to improve the strength of the first strengthening area 103 and the second strengthening area 102 at the top, especially the tensile strength.

[0092] The difference from the above embodiment lies in the structural change of the support cage. In combination with Figure 9 and Figure 10 As shown, the support structure includes a second support cage 200b and a connection structure 210. The second support cage 200b includes support columns 201 and a corrugated mesh structure 203 connected to the outside of the support columns 201. The bag body 100 is wrapped outside the support net 202 and fits outside the support net 202, so that the filtering area of the dust removal filter bag is larger.

[0093] Combined with the above embodiments, the present invention sets closed-cell regions on the PTFE film layer and convex structures on the base layer. When the PTFE film layer and the base layer are laminated, the convex structures of the base material are combined with the closed-cell regions of the PTFE film layer. By hot-pressing to melt the entanglement of the molecular chains of PTFE and the base material, chemical bonding force is generated, enhancing the interfacial bonding strength. Especially under high-temperature vibration conditions, the anti-delamination ability is significantly enhanced, and the service life of the filter bag structure is extended.

[0094] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Those with ordinary knowledge in the technical field to which the present invention pertains can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to what is defined by the claims.

Claims

1. A high-temperature resistant and anti-detachment PTFE coated filter layer, characterized in that, Comprising: A PTFE film layer (10), including a microporous region (11) and a plurality of closed pore regions (12). The PTFE film layer (10) has a plurality of micropores penetrating the PTFE film layer (10) in the microporous region (11), and the closed pore regions (12) of the PTFE film layer (10) do not contain such micropores or have a porosity less than 5%; A base layer (20), which includes a first thickness layer (22) and a plurality of protruding structures (21) extending from the surface of the first thickness layer (22) along its thickness direction to a second thickness layer. The base layer (20) includes a woven fiber cloth substrate or a non-woven fiber cloth substrate; Wherein, a plurality of the closed pore regions (12) are regularly distributed in the PTFE film layer (10), and adjacent closed pore regions (12) do not contact each other. The PTFE film layer (10) and the base layer (20) are fixed to each other, and the protruding structures (21) of the base layer (20) correspond to the positions of the closed pore regions (12) of the PTFE film layer (10) and are in contact with each other.

2. The high-temperature resistant and anti-detachment PTFE film filter layer according to claim 1, wherein The closed pore regions (12) in the PTFE film layer (10) account for 10 - 20% of the total area of the PTFE film layer (10).

3. The high-temperature resistant and anti-sloughing PTFE film-coated filter layer according to claim 1, wherein The diameter of the closed pore regions (12) is 0.5 - 1 mm, the spacing between adjacent closed pore regions (12) is 1 - 3 mm, and a plurality of the closed pore regions (12) are distributed in a matrix array or a honeycomb shape.

4. The high-temperature resistant and anti-detachment PTFE coated filter layer according to claim 3, wherein, The protruding height of the protruding structures (21) is 0.1 - 0.3 mm, and the protruding structures (21) are arranged such that the cross-sectional diameter near the first thickness layer (22) is larger than the cross-sectional diameter near the second thickness layer.

5. The high-temperature resistant and anti-detachment PTFE coated filter layer according to claim 1, wherein The surface of the protruding structures (21) is provided with a polyphenylene sulfide or polyimide adhesive layer, and the thickness of the adhesive layer is 5 - 15 microns.

6. The high-temperature resistant and anti-detachment PTFE film-coated filter layer according to any one of claims 1-5, characterized in that, The contact interface between the protruding structures (21) and the closed pore regions (12) forms a molten bonding layer through hot pressing.

7. The high-temperature resistant and anti-detachment PTFE coated filter layer according to any one of claims 1-5, characterized in that A gradual transition zone is provided around the microporous region (11). In the gradual transition zone, the micropores are arranged with a gradually changing pore diameter, which gradually increases from 0 to 0.5 microns according to the distance from the center of the microporous region (11).

8. The preparation method of the high-temperature resistant and anti-detachment PTFE coated filter layer according to any one of claims 1-7, characterized in that, Including the following steps: Step 1, processing of the PTFE film layer (10): The PTFE film layer (10) is subjected to biaxial stretching to form a microporous film, and micropores in a predetermined region of the PTFE film layer (10) are closed by laser selective sintering or femtosecond laser to form a plurality of closed pore regions (12); Step 2, processing of the base layer (20): A plurality of protruding structures (21) are formed on the surface of the base layer (20) by hot embossing; Step 3, film layer lamination: Align the protruding structures (21) of the base layer (20) with the closed pore regions (12) of the PTFE film layer (10), and hot press for a preset duration at a predetermined temperature and pressure to achieve interfacial molten bonding.

9. The preparation method of the high-temperature resistant and anti-detachment PTFE film-coated filter layer according to claim 8, characterized in that, If the base layer (20) is a woven fiber cloth, multiple raised structures (21) are formed by hot pressing with a hot pressing mold at a temperature of 300 - 400 °C and a pressure of 5 - 10 MPa; if the base layer (20) is a non-woven fiber cloth, multiple raised structures (21) are formed by an ultrasonic embossing process at a frequency of 20 - 40 kHz and a linear pressure of 100 - 150 N / cm.

10. A dust removal filter bag, characterized in that, It includes: A support structure, including a support cage and a connecting structure (210); A bag body (100), including an opening, and the bag body (100) is sleeved outside the support cage, and the opening extends and is fixed to the outside of the connecting structure (210); Wherein, the bag body (100) is made of the high-temperature resistant and anti-detachment PTFE coated filter layer described in any one of claims 1 - 7; The bag body (100) is arranged to fit the surface of the support cage, and the bag body (100) is arranged as a cylindrical bag body or a columnar bag body with pleats on the side wall.

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