High-temperature-resistant composite filter material

Abstract

The utility model discloses a high-temperature-resistant composite filter material which comprises a filter felt, the upper side of the filter felt is covered with a layer of polyimide nanofiber membrane, boron nitride nanosheets are doped in the polyimide nanofiber membrane, and the upper side of the polyimide nanofiber membrane is covered with a layer of boron nitride membrane. The polyimide nanofiber membrane can be separated from high-temperature gas and corrosive gas by using the boron nitride membrane, so that the service life of the polyimide nanofiber membrane is prolonged. The polyimide nanofiber membrane can intercept most of dust, has the characteristics of good air permeability, good hydrophobicity, high mechanical strength and the like required by a conventional filtering membrane, and is superior to a conventional polytetrafluoroethylene membrane and even superior to a conventional polyimide membrane in temperature resistance due to the addition of the boron nitride nanosheets; the effects of high temperature resistance, chemical corrosion resistance and creep resistance are achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of dust collector filter bags, in particular to a high-temperature resistant composite filter material. Background Art

[0002] High-temperature resistant filter materials made of polyimide (PI) short fibers have the advantages of high cost-effectiveness, easy cleaning, and long service life. Therefore, they are widely used in the field of high-temperature filtration and dust removal. However, polyimide itself does not have water- and oil-repellent properties and is easily hydrolyzed in an alkaline environment, resulting in a decrease in the breaking strength of the polyimide filter material or bag sticking, seriously affecting the dust removal efficiency of the filter bag.

[0003] To improve the filtration performance and lifespan of filter media, polyimide filter media is typically coated with a polytetrafluoroethylene (PTFE) membrane. However, this coating can creep at high temperatures, potentially changing the membrane's structure and affecting filtration efficiency. Base fabrics suitable for high-temperature environments are typically PTFE-based, polyimide-based, and aramid-based. However, PTFE-based fabrics can creep at high temperatures, resulting in a decrease in mechanical properties. Polyimide and aramid-based fabrics are also not chemically resistant. Utility Model Content

[0004] The purpose of the utility model is to provide a high-temperature resistant composite filter material, which has the advantages of high-temperature resistance, chemical corrosion resistance and extended service life of the filter material.

[0005] In order to achieve the above objectives, the solution of the present invention is:

[0006] A high-temperature resistant composite filter material comprises a filter felt, the upper side of which is covered with a layer of polyimide nanofiber membrane doped with boron nitride nanosheets, and the upper side of the polyimide nanofiber membrane is covered with a layer of boron nitride membrane.

[0007] Furthermore, the polyimide nanofiber membrane is composed of polyimide nanofibers doped with boron nitride nanosheets and is prepared by an electrostatic spinning method.

[0008] Furthermore, the polyimide nanofibers of the polyimide nanofiber membrane have a diameter of 50 nm to 800 nm and a pore size of 0.5 μm to 30 μm.

[0009] Furthermore, the mass ratio of boron nitride nanosheets to polyimide nanofibers in the polyimide nanofiber membrane is 5-10:100.

[0010] Furthermore, the filter felt includes a base fabric layer, a first fiber layer and a second fiber layer, and the first fiber layer and the second fiber layer are respectively arranged on the upper and lower sides of the base fabric layer; the first fiber layer and the second fiber layer are both fiber felts made of polyimide fibers doped with boron nitride nanosheets.

[0011] Furthermore, the base fabric layer is made of polyetheretherketone, and the base fabric layer has a gram weight of 100g / m 2 -300g / m 2 .

[0012] Furthermore, the mass ratio of the boron nitride nanosheets to the polyimide fibers in the first fiber layer and the second fiber layer is 5-10:100.

[0013] Furthermore, the polyimide fibers doped with boron nitride nanosheets in the first fiber layer and the second fiber layer have a fiber fineness of 1.0 dtex to 2.2 dtex and a length of 48 mm to 76 mm.

[0014] Furthermore, the first fiber layer, the base fabric layer and the second fiber layer are reinforced by needle punching and hydroentanglement to form a fiber mat; the fiber mat has a thickness of 1.5mm-3.0mm and a gram weight of 300g / m 2 -600g / m 2 The transverse and longitudinal breaking strengths of the fiber felt with a sample size of 5cm*20cm are both ≥900N.

[0015] Furthermore, the boron nitride film is prepared by depositing it on the surface of the polyimide nanofiber membrane using a vapor deposition method.

[0016] By adopting the above technical solution, the boron nitride membrane can be used to isolate the polyimide nanofiber membrane from high-temperature and corrosive gases, extending the service life of the polyimide nanofiber membrane. The polyimide nanofiber membrane can intercept most dust particles while also possessing the good air permeability, good hydrophobicity, and high mechanical strength required of conventional filter membranes. Furthermore, due to the addition of boron nitride nanosheets, the temperature resistance is superior to that of conventional polytetrafluoroethylene membranes, and even better than that of conventional polyimide membranes. It also has excellent resistance to high temperatures, chemical corrosion, and creep.

[0017] In addition, boron nitride is also added to the polyimide fiber, which makes the fiber's glass transition temperature, thermal decomposition temperature and heat resistance index higher than conventional pure PI fiber, thereby improving the PI fiber's high temperature resistance and oxidation resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of an embodiment of the present utility model;

[0019] Figure 2 This is a scanning electron microscope image of a polyimide nanofiber membrane according to an embodiment of the present invention;

[0020] Explanation of reference numerals: composite filter material 100 , filter felt 10 , base fabric layer 11 , first fiber layer 12 , second fiber layer 13 , polyimide nanofiber membrane 20 , boron nitride membrane 30 , boron nitride nanosheet 1 . DETAILED DESCRIPTION

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0022] like Figure 1 As shown, a high-temperature resistant composite filter material 100 provided in this embodiment includes a filter felt 10, the upper side of the filter felt 10 is covered with a layer of polyimide nanofiber membrane 20, the polyimide nanofiber membrane 20 is doped with boron nitride nanosheets 1, and the upper side of the polyimide nanofiber membrane 20 is covered with a layer of boron nitride membrane 30.

[0023] In the composite filter material 100 of this embodiment, the boron nitride membrane 30 can be used to isolate the polyimide nanofiber membrane 20 from high-temperature and corrosive gases, thereby extending the service life of the polyimide nanofiber membrane 20. The polyimide nanofiber membrane 20 can intercept most dust particles while also possessing the characteristics of good air permeability, good hydrophobicity, and high mechanical strength required of conventional filter membranes. Moreover, due to the addition of the boron nitride nanosheets 1, the temperature resistance is better than that of conventional polytetrafluoroethylene membranes and conventional polyimide membranes.

[0024] In this embodiment, the boron nitride film 30 can be prepared by depositing it on the surface of the polyimide nanofiber film 20 using a vapor deposition method.

[0025] The polyimide nanofiber membrane 20 may be composed of polyimide nanofibers doped with boron nitride nanosheets 1, and may be generally prepared by an electrospinning method; the mass ratio of the boron nitride nanosheets 1 to the polyimide nanofibers in the polyimide nanofiber membrane 20 may be 5 to 10:100; the polyimide nanofibers in the polyimide nanofiber membrane 20 may have a diameter of 50 nm to 800 nm, and a pore size of 0.5 μm to 30 μm (see Figure 2 ) to have a good filtering effect.

[0026] This embodiment mainly improves conventional polyimide filter materials.

[0027] The filter felt 10 includes a base fabric layer 11 , a first fiber layer 12 and a second fiber layer 13 . The first fiber layer 12 and the second fiber layer 13 are respectively arranged on the upper and lower sides of the base fabric layer 11 .

[0028] Both the first fiber layer 12 and the second fiber layer 13 can be fiber mats made of polyimide fibers doped with boron nitride nanosheets 1, with the mass ratio of boron nitride nanosheets to polyimide fibers being 5 to 10:100. The boron nitride nanosheets 1 impart excellent oxidation and corrosion resistance to the polyimide, making it suitable for high-temperature environments. The first and second fiber layers 12, 13 can be produced using a non-woven process, with a fiber fineness of 1.0 to 2.2 dtex and a length of 48 to 76 mm.

[0029] The base fabric layer 11 can be made of polyetheretherketone, and the base fabric layer 11 has a weight of 100 g / m 2 -300g / m 2 . It has properties such as high temperature resistance, chemical corrosion resistance and creep resistance.

[0030] The first fiber layer 12, the base fabric layer 11 and the second fiber layer 13 are reinforced by needle punching and hydroentanglement to form a fiber mat; the fiber mat has a thickness of 1.5mm-3.0mm and a gram weight of 300g / m 2 -600g / m 2 The horizontal and vertical breaking strengths are both ≥900N (strip size 5cm*20cm). The fibers are tightly entangled and can intercept a small amount of dust that penetrates, ensuring ultra-low emission of the filter material.

[0031] In summary, the addition of boron nitride nanosheets 1 increases the glass transition temperature, thermal decomposition temperature, and heat resistance index of the filter felt 10 comprising the first fiber layer 12 and the second fiber layer 13 to higher values than those of conventional polyimide filter media, effectively improving the polyimide fiber's antioxidant and corrosion resistance. Furthermore, the composite filter media 100 of this embodiment utilizes materials with excellent temperature resistance, enabling continuous and efficient filtration in high-temperature environments, achieving a filtration efficiency of up to 99.99%.

[0032] The utility model also has at least the following advantages:

[0033] 1. Adding boron nitride nanosheets 1 into polyimide fibers can improve the high temperature resistance and chemical corrosion resistance of the polyimide fibers and extend the service life of the filter media.

[0034] 2. Boron nitride nanosheets 1 are incorporated into the electrospun polyimide fiber membrane to improve the membrane's high-temperature and chemical corrosion resistance. The boron nitride membrane 30 on the surface acts as a barrier, reducing damage to the filter media from high-temperature corrosive gases. Existing solutions typically use PTFE membranes, which are prone to high-temperature creep.

[0035] 3. The base fabric is made of polyetheretherketone (PEEK), which is resistant to high temperatures, chemical corrosion, and creep. Existing base fabrics suitable for high-temperature environments are typically polytetrafluoroethylene (PTFE), polyimide (PI), and aramid (Kevlar). However, PTFE exhibits high-temperature creep, resulting in a decrease in mechanical properties. Polyimide and aramid base fabrics are not resistant to acid and alkali corrosion.

[0036] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiment. All technical solutions based on the concept of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, equivalent changes and modifications that do not depart from the principles of the present invention should still fall within the scope of protection of the present invention.

Claims

1. A high temperature resistant composite filter material, characterized by: The filter felt comprises a filter felt, the upper side of which is covered with a layer of polyimide nanofiber membrane, wherein the polyimide nanofiber membrane is doped with boron nitride nanosheets, and the upper side of the polyimide nanofiber membrane is covered with a layer of boron nitride membrane.

2. The high temperature resistant composite filter material according to claim 1, characterized in that: The polyimide nanofiber membrane is composed of polyimide nanofibers doped with boron nitride nanosheets and is prepared by an electrostatic spinning method.

3. The high temperature resistant composite filter material according to claim 2, characterized in that: The polyimide nanofiber of the polyimide nanofiber membrane has a diameter of 50 nm to 800 nm and a pore size of 0.5 μm to 30 μm.

4. The high temperature resistant composite filter material according to claim 2, characterized in that: The mass ratio of the boron nitride nanosheets to the polyimide nanofibers in the polyimide nanofiber membrane is 5-10:

100.

5. The high temperature resistant composite filter material according to claim 1, characterized in that: The filter felt includes a base fabric layer, a first fiber layer and a second fiber layer, wherein the first fiber layer and the second fiber layer are respectively arranged on the upper and lower sides of the base fabric layer; the first fiber layer and the second fiber layer are both fiber felts made of polyimide fibers doped with boron nitride nanosheets.

6. The high temperature resistant composite filter material according to claim 5, characterized in that: The base fabric layer is made of polyetheretherketone, and the base fabric layer has a gram weight of 100g / m 2 -300g / m 2 .

7. The high temperature resistant composite filter material according to claim 5, characterized in that: The mass ratio of the boron nitride nanosheets to the polyimide fibers in the first fiber layer and the second fiber layer is 5-10:

100.

8. The high temperature resistant composite filter material according to claim 7, characterized in that: The polyimide fibers doped with boron nitride nanosheets in the first fiber layer and the second fiber layer have a fiber fineness of 1.0 dtex to 2.2 dtex and a length of 48 mm to 76 mm.

9. A high temperature resistant composite filter material according to any one of claims 5 to 8, characterized in that: The first fiber layer, the base fabric layer and the second fiber layer are reinforced by needle punching and hydroentanglement to form a fiber mat; the fiber mat has a thickness of 1.5mm-3.0mm and a gram weight of 300g / m 2 -600g / m 2 The transverse and longitudinal breaking strengths of the fiber felt with a sample size of 5cm*20cm are both ≥900N.

10. The high temperature resistant composite filter material according to claim 1, characterized in that: The boron nitride film is prepared by depositing it on the surface of a polyimide nanofiber film through a vapor deposition method.

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