High-humidity-resistant filter material and preparation method thereof

Abstract

The invention belongs to the technical field of protective materials, and relates to a high-humidity-resistant filter material and a preparation method thereof.The method comprises the steps that a filter material body is sequentially provided with a first hydrophilic fiber layer, a second hydrophilic fiber layer and a core filter layer in a stacked mode from outside to inside; the thickness of the second hydrophilic fiber layer is increased in a gradient manner from top to bottom. The filter material has the beneficial effects that water is fully diffused in the first hydrophilic fiber layer and then is transmitted into the second hydrophilic fiber layer, and the second hydrophilic fiber layer is of a wedge-shaped structure with a small upper end thickness and a large lower end thickness, so that the absorbed water is finally converged to the bottom, and the resistance of the filter material is slowly increased in a long-term use process. The filter material provided by the invention can realize gradient diffusion of water in a short time, greatly alleviates the problem of high resistance increase speed of the filter material in a high-humidity environment, protects static electricity of the core filter layer from being influenced by humidity, and realizes high efficiency and low resistance in the service life of the filter material.

Description

Technical Field

[0001] The invention relates to the technical field of protective materials, and in particular to a high-humidity resistant filter material and a preparation method thereof. Background Art

[0002] Fiber filter media is widely used in the field of air filtration, and its most important filtration performance includes filtration efficiency and resistance. With the emergence of high-efficiency filter media such as nanofiber filter media, high-density surface filter media, and electrostatic filter media, high filtration efficiency is no longer a major problem. The resistance of the filter media is too high, especially in a high-humidity environment, the resistance of the filter media increases rapidly in a short period of time, which has become a key problem that the existing filter media urgently needs to solve.

[0003] In order to solve the problem of too fast increase of filter material resistance in high humidity environment, the main technical measure currently adopted is to treat the filter material with super hydrophobicity, so that water vapor can pass through the filter material without blocking the filter material pores. However, when water vapor and droplets exist at the same time, the droplets will accumulate on the surface of the hydrophobic filter material and block the filter material pores, causing the filter material resistance to increase rapidly. For example, in tunnel mining working faces, a combination of spray dust reduction and filter material dust removal is often used. The droplets generated by the spray will cause the filter material resistance to rise rapidly, greatly affecting the normal use of the filter material.

[0004] Therefore, superhydrophobic filter materials cannot solve the problem of rapid increase in resistance when water vapor and droplets coexist. Summary of the invention

[0005] Technical issues to be solved: In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a high-humidity resistant filter material and a preparation method thereof, which solves the technical problem of how to alleviate the excessively rapid increase in filter material resistance under a high-humidity environment.

[0006] Technical solution: In order to achieve the above object, the main technical solutions adopted by the present invention include: In a first aspect, the present invention provides a high-humidity resistant filter material, wherein a first hydrophilic fiber layer, a second hydrophilic fiber layer and a core filter layer are sequentially stacked from the outside to the inside of the filter material body; The thickness of the second hydrophilic fiber layer increases gradually from top to bottom.

[0007] Optionally, the first hydrophilic fiber layer is made of hydrophilic polyester, hydrophilic polyurethane or hollow fiber with capillary action, the water absorption rate of which is greater than 0.2 cm / s.

[0008] Optionally, the first hydrophilic fiber layer has a thickness of 3 mm to 5 mm.

[0009] Optionally, the second hydrophilic fiber layer is a hydrophilic fiber web wrapped with super absorbent resin particles or powder, and the super absorbent resin particles or powder are evenly distributed between the two layers of hydrophilic fiber web.

[0010] Optionally, the super absorbent resin in the second hydrophilic fiber layer is polyacrylic acid salt, starch acrylate polymer, starch-acrylonitrile graft copolymer or acrylamide-acrylonitrile-acrylic acid terpolymer with a water absorption capacity greater than 30 g / g.

[0011] Optionally, the second hydrophilic fiber layer has an upper thickness of 2 mm to 4 mm and a lower thickness of 4 mm to 10 mm.

[0012] Optionally, the core filter layer is one of the electret filter materials with electrostatic effect, specifically melt-blown polypropylene or electrospun nanofiber membrane.

[0013] Optionally, the core filter layer has a thickness of 5 mm to 15 mm.

[0014] In a second aspect, the present invention provides a method for preparing a high-humidity resistant filter material, comprising: S1, preparing the core filter layer by melt-blowing, electrospinning or corona electret; S2, preparing hydrophilic fibers or particles with a large water capacity into a second hydrophilic fiber layer with a thickness gradient increasing from top to bottom; S3, the first hydrophilic fiber layer, the second hydrophilic fiber layer and the core filter layer are stacked in sequence from outside to inside; S4. The first hydrophilic fiber layer, the second hydrophilic fiber layer and the core filter layer are tightly bonded together by heat pressing and / or gluing to form a high-humidity resistant filter material.

[0015] Beneficial effects: The beneficial effects of the present invention are as follows: a high-humidity resistant filter material of the present invention presents a multi-layer structure with gradually changing hydrophilic properties from the outside to the inside, the outermost layer is a hydrophilic fiber layer with a fast water absorption speed, the second layer is a hydrophilic fiber layer with a large water capacity, and the third layer is a core filter layer with an electrostatic adsorption effect. In a high-humidity environment, water vapor or droplets quickly diffuse in the hydrophilic fiber layer after contacting the filter material, and will not form a liquid film to block the pores of the fiber mesh, thereby ensuring that the resistance of the filter material will not increase rapidly in the initial use. After the water is fully diffused in the hydrophilic fiber layer, it is transmitted to the hydrophilic fiber layer. The hydrophilic fiber layer is a wedge-shaped structure with a small thickness at the upper end and a large thickness at the lower end, thereby ensuring that the absorbed water eventually converges to the bottom, so that the resistance of the filter material increases slowly during long-term use. The filter material provided by the present invention can make water diffuse gradually in a short time, greatly alleviating the problem of the fast increase rate of the filter material resistance in a high-humidity environment, while protecting the static electricity of the core filter layer from being affected by humidity, thereby achieving high efficiency and low resistance within the service life of the filter material. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of the overall structure of a high-humidity resistant filter material provided in an embodiment of the present invention; Figure 2 A test diagram of water absorption speed of a first hydrophilic fiber layer material (polyurethane) used in a high-humidity resistant filter material provided in an embodiment of the present invention; Figure 3 A test diagram of water absorption speed of a second hydrophilic fiber layer material (sodium polyacrylate) used in a high-humidity resistant filter material provided in an embodiment of the present invention; Figure 4 A resistance growth trend diagram of a high-humidity resistant filter material provided by an embodiment of the present invention under the condition of coexistence of water droplets and water vapor; Figure 5 A test chart of water absorption speed of a first hydrophilic fiber layer material (polyester) used in a high-humidity resistant filter material provided in an embodiment of the present invention; Figure 6 An exemplary diagram of a high-humidity resistant filter material provided by an embodiment of the present invention for use in individual respiratory protection equipment; Figure 7 A high humidity resistant filter material provided in an embodiment of the present invention is used for a resistance growth diagram of individual respiratory protection equipment under high humidity.

[0017] Description of reference numerals: 1: first hydrophilic fiber layer; 2: second hydrophilic fiber layer; 3: Core filter layer. DETAILED DESCRIPTION

[0018] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below in conjunction with the accompanying drawings through specific embodiments. In order to better understand the above technical solution, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a clearer and more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0019] Embodiment 1 First, refer to Figure 1 This embodiment provides a high-humidity resistant filter material, wherein the filter material body is sequentially stacked from the outside to the inside to form a first hydrophilic fiber layer 1, a second hydrophilic fiber layer 2 and a core filter layer 3; The thickness of the second hydrophilic fiber layer 2 increases gradually from top to bottom.

[0020] The first hydrophilic fiber layer 1 is a hydrophilic fiber material with fast water absorption speed and small volume expansion after water absorption; the second hydrophilic fiber layer 2 is a hydrophilic fiber material with large water holding capacity; the core filter layer 3 is a polypropylene melt-blown cloth material with electrostatic adsorption effect.

[0021] The high humidity resistant filter material is used in a high humidity environment, and the humidity of the high humidity environment is ≥100% (an environment where water vapor and liquid droplets are mixed).

[0022] The mechanism of high-humidity resistant filter media is as follows: after water vapor or liquid droplets come into contact with the filter media, they quickly diffuse in the first hydrophilic fiber layer 1, and no liquid film will be formed to block the pores of the fiber mesh, ensuring that the resistance of the filter media will not increase rapidly in the initial use. After the water fully diffuses in the first hydrophilic fiber layer 1, it is transferred to the second hydrophilic fiber layer 2. The second hydrophilic fiber layer 2 is a wedge-shaped structure with a small thickness at the upper end and a large thickness at the lower end, ensuring that the absorbed water eventually converges to the bottom, so that the resistance of the filter media increases slowly in long-term use, and at the same time protects the core filter layer from charge decay under the action of humidity.

[0023] Optionally, the first hydrophilic fiber layer 1 is made of a hydrophilic material such as hydrophilic polyester, hydrophilic polyurethane, or hollow fiber with capillary action, with a water absorption rate greater than 0.2 cm / s.

[0024] Optionally, the first hydrophilic fiber layer 1 has a thickness of 3 mm to 5 mm.

[0025] Optionally, the second hydrophilic fiber layer 2 is a hydrophilic fiber web wrapped with super absorbent resin particles or powder, and the super absorbent resin particles or powder are evenly distributed between the two layers of hydrophilic fiber web.

[0026] Optionally, the super absorbent resin in the second hydrophilic fiber layer 2 is a super absorbent resin such as polyacrylic acid salt, starch acrylate polymer, starch-acrylonitrile graft copolymer or acrylamide-acrylonitrile-acrylic acid terpolymer with a water absorption capacity greater than 30g / g (each gram of absorbent resin can absorb 30g of water).

[0027] Optionally, the second hydrophilic fiber layer 2 has an upper thickness of 2 mm to 4 mm and a lower thickness of 4 mm to 10 mm.

[0028] Optionally, the core filter layer is one of the electret filter materials with electrostatic effect, specifically melt-blown polypropylene or electrospun nanofiber membrane.

[0029] Optionally, the core filter layer has a thickness of 5 mm to 15 mm.

[0030] In a second aspect, this embodiment provides a method for preparing a high-humidity resistant filter material, comprising: S1, preparing the core filter layer by melt-blowing, electrospinning or corona electret; S2, preparing hydrophilic fibers or particles with a large water capacity into a second hydrophilic fiber layer 2 with a thickness gradient increasing from top to bottom; S3, the first hydrophilic fiber layer 1, the second hydrophilic fiber layer 2 and the core filter layer 3 are stacked in sequence from outside to inside; S4. The first hydrophilic fiber layer 1, the second hydrophilic fiber layer 2 and the core filter layer 3 are tightly bonded together by heat pressing and / or gluing to form a high-humidity resistant filter material.

[0031] According to the method for preparing a high-humidity resistant filter material provided in this embodiment, since it is used to prepare a high-humidity resistant filter material provided in the first aspect embodiment of the present invention, the method for preparing a high-humidity resistant filter material has all the technical effects of the high-humidity resistant filter material, and will not be repeated here.

[0032] Embodiment 2 Reference Figure 1 Preparation of high-humidity filter material with sandwich structure. First, a polyurethane fiber layer with a water absorption speed of 150ms (the time to absorb 1ml of water) is selected as the first hydrophilic fiber layer 1, such as Figure 2 As shown, cut to the required size. Weigh an appropriate amount of sodium polyacrylate (the appropriate standard is 5g / cm 2 -10g / cm 2 ) particles, the water absorption rate of sodium polyacrylate particles is 6s. Figure 3 As shown, the water capacity is 73g / g (1g of sodium polyacrylate can absorb 73g of water), and the particles are laid flat on the hot melt adhesive film according to the principle of thin top and thick bottom as the second hydrophilic fiber layer 2. The polypropylene electret filter material is prepared by melt-blowing process as the core filter layer.

[0033] The first polyurethane hydrophilic fiber layer 1, the second sodium polyacrylate hydrophilic fiber layer 2, the hot melt adhesive film, and the polypropylene core filter layer are compounded together by hot pressing to form a high-humidity resistant filter material. Compared with ordinary filter materials, the resistance growth of the high-humidity resistant filter material is significantly slower in a high-humidity environment. The resistance growth is less than 500Pa within 4 hours, while the resistance growth of ordinary filter materials is 1500Pa. Figure 4 After testing in a high humidity environment, the efficiency of the high humidity resistant filter material remained above 90%, while the efficiency of the ordinary filter material dropped to 75% because the charge of the polypropylene core filter layer was neutralized by water vapor.

[0034] Embodiment 3 Reference Figure 1 Preparation of high-humidity filter material with sandwich structure. First, a polyester fiber layer with a water absorption rate of 4 cm / min is selected as the first hydrophilic fiber layer 1, such as Figure 5 , cut to the required size. Weigh an appropriate amount of sodium polyacrylate (the appropriate standard is 5g / cm 2 -10g / cm 2 ) particles, the water absorption rate of sodium polyacrylate particles is 6s. Figure 3The water capacity is 73g / g (1g of sodium polyacrylate can absorb 73g of water). The particles are laid flat on the hot melt adhesive film according to the principle of thin top and thick bottom as the second hydrophilic fiber layer 2. In this example, the second hydrophilic fiber layer 2 has a trapezoidal structure. The polyester fiber layer, sodium polyacrylate hydrophilic layer, polyester fiber layer, hot melt adhesive film, and polypropylene melt-blown cloth are hot-pressed and compounded in the order of hot pressing to prepare a high-humidity resistant filter material.

[0035] The prepared high humidity resistant filter material is used as the core filter material of respiratory protective equipment, such as Figure 6 As shown. The respiratory protective equipment made of high-humidity resistant filter material was tested in a mine 800 meters underground. The temperature in the mine was 40°C, the relative humidity was 100%, and there was fine water mist. Compared with ordinary respiratory protective equipment, the resistance of the respiratory protective equipment made of high-humidity resistant filter material increased significantly slower in a high-humidity environment. After 5 hours of use, the resistance increased to 450Pa, while the resistance of ordinary respiratory protective equipment increased to 700Pa. Figure 7 The high-humidity resistant filter material significantly alleviates the breathing discomfort caused by increased resistance.

[0036] Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention should also include these modifications and variations.

[0037] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may alter, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A high humidity resistant filter material, characterized in that: The filter material body is stacked in sequence from the outside to the inside, with a first hydrophilic fiber layer (1), a second hydrophilic fiber layer (2) and a core filter layer (3); The thickness of the second hydrophilic fiber layer (2) increases gradually from top to bottom.

2. A high humidity resistant filter material according to claim 1, characterized in that: The material of the first hydrophilic fiber layer (1) is hydrophilic polyester, hydrophilic polyurethane or hollow fiber with capillary action, with a water absorption rate greater than 0.2 cm / s.

3. A high humidity resistant filter material according to claim 2, characterized in that: The first hydrophilic fiber layer (1) has a thickness of 3 mm to 5 mm.

4. A high humidity resistant filter material according to claim 3, characterized in that: The second hydrophilic fiber layer (2) is a hydrophilic fiber web wrapped with highly absorbent resin particles or powder, and the highly absorbent resin particles or powder are evenly distributed between the two layers of hydrophilic fiber web.

5. A high humidity resistant filter material according to claim 4, characterized in that: The highly water-absorbent resin in the second hydrophilic fiber layer (2) is a polyacrylic acid salt, a starch acrylate polymer, a starch-acrylonitrile graft copolymer or an acrylamide-acrylonitrile-acrylic acid terpolymer having a water absorption capacity greater than 30 g / g.

6. A high humidity resistant filter material according to claim 5, characterized in that: The second hydrophilic fiber layer (2) has an upper thickness of 2 mm to 4 mm and a lower thickness of 4 mm to 10 mm.

7. A high humidity resistant filter material according to claim 6, characterized in that: The core filter layer is one of the electret filter materials with electrostatic effect, specifically melt-blown polypropylene or electrostatically spun nanofiber membrane.

8. The high humidity resistant filter material according to claim 7, characterized in that: The thickness of the core filter layer is 5 mm to 15 mm.

9. A method for preparing a high-humidity resistant filter material, characterized in that: include: S1, preparing the core filter layer by melt-blowing, electrospinning or corona electret; S2, preparing hydrophilic fibers or particles with a large water capacity into a second hydrophilic fiber layer (2) with a thickness gradient increasing from top to bottom; S3, the first hydrophilic fiber layer (1), the second hydrophilic fiber layer (2) and the core filter layer (3) are stacked in sequence from the outside to the inside; S4. The first hydrophilic fiber layer (1), the second hydrophilic fiber layer (2) and the core filter layer (3) are tightly bonded together by heat pressing and / or gluing to form a high-humidity resistant filter material.

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