Virus removal filter and mask using same

Abstract

To provide a virus removing filter having sufficient breathability, having virus removing performances and being excellent as a mask member.SOLUTION: A virus removing filter comprises: a first base material 11 composed of an open-cell foam sheet; an intermediate fiber layer 31 composed of a nanofiber formed on one surface of the first base material 11; and a second base material 21 composed of an open-cell foam sheet superposed on the intermediate fiber layer 31. The open-cell foam sheets of the first base material 11 and the second base material 21 are defined as a skinned soft slab polyurethane foam sheet, and the nanofiber of the intermediate fiber layer 31 is defined as a polyurethane.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a virus removal filter and a mask using the same. [Background technology]

[0002] Conventional masks include those made of gauze (Patent Document 1) and those made of urethane foam (Patent Document 2). However, masks made of gauze or urethane foam have coarse meshes and are not sufficient in terms of virus removal performance.

[0003] Also, a mask made of a composite fabric of a nanofiber nonwoven fabric layer and at least one layer of fabric has been proposed (Patent Document 3). However, this mask is intended to ensure wind resistance, moisture permeability, and stretchability, and does not disclose its ability to remove viruses. Furthermore, because it uses a nonwoven fabric as the base material, it does not adhere well to the face, which is likely to reduce the virus removal rate.

[0004] Additionally, masks that claim to remove viruses have also appeared on the market, but viruses are less than 1 μm in size, and if the mesh of the filter that makes up the mask is made finer, the breathability decreases, and some people find it difficult to breathe when wearing the mask for long periods of time.

[0005] A mask made by laminating a nanofiber nonwoven fabric with an inorganic porous substance loaded on it and a microfiber nonwoven fabric has been disclosed as a mask designed to efficiently block viruses, bacteria, etc. and inactivate or kill captured viruses, bacteria, etc. (Patent Document 4). However, because the microfiber fibers themselves are thick, this mask has an extremely low porosity per unit area, reducing breathability and potentially making the wearer feel short of breath after prolonged use. Furthermore, when nonwoven fabric is used as the base material for a mask, the low stretchability and flexibility of the nonwoven fabric result in insufficient conformity to the skin, potentially allowing viruses, etc., to penetrate through gaps between the skin and the mask. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Utility Model Application Publication No. 53-4799 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-136754 [Patent Document 3] Japanese Patent Application Laid-Open No. 2014-234561 [Patent Document 4] Japanese Patent Application Laid-Open No. 2008-188082 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made in consideration of the above points, and an object of the present invention is to provide a virus removal filter that is sufficiently breathable and has virus removal performance, and a mask using the same. [Means for solving the problem]

[0008] The first aspect is a first substrate made of an open-cell foam sheet; a second substrate made of an open-cell foam sheet; an intermediate fibrous layer positioned between the first substrate and the second substrate; A filter composed of a laminate of BFE collection rate is 60% or more, and the air permeability is 30cm 3 / cm 2 ·sec or more (excluding those containing activated carbon in the intermediate fiber layer).

[0009] The second aspect is In the filter according to the first aspect, the first substrate or the second substrate is made of an open-cell polyurethane foam sheet. The third aspect is The intermediate fiber layer has a basis weight of 0.10 to 0.80 g / m 2 The filter according to the first or second aspect is characterized in that: The fourth aspect is A mask comprising the filter according to any one of the first to third aspects.

[0010] The fifth aspect is a first substrate made of an open-cell foam sheet; a second substrate made of an open-cell foam sheet; an intermediate fibrous layer positioned between the first substrate and the second substrate; A mask consisting only of a laminate of BFE collection rate is 60% or more, and the air permeability is 30cm 3 / cm 2 sec or more.

[0011] The sixth aspect is The mask according to a fifth aspect is characterized in that the first substrate or the second substrate is made of an open-cell polyurethane foam sheet. A seventh aspect is The intermediate fiber layer has a basis weight of 0.10 to 0.80 g / m 2 The mask according to the fifth or sixth aspect is characterized in that: [Effects of the Invention]

[0012] One aspect According to the present invention, since the filter has an intermediate fiber layer made of nanofibers, it can efficiently remove viruses at the nano level. Furthermore, by using open-cell foam sheets for the first substrate and the second substrate, the air permeability of the virus removal filter is increased, making it less likely to become clogged or lose its air permeability even after long-term use.

[0013] Also, one aspect According to the disclosure, the open-cell foam sheet is made of a soft slab polyurethane foam sheet from which the membrane has been removed, thereby ensuring high breathability.

[0014] Also, one aspect According to the method, since the nanofibers are made of polyurethane, when the nanofibers are formed on one side of the first substrate, a nanofiber layer having high adhesion between the first substrate and the nanofibers and having good stretchability can be obtained.

[0015] Also, one aspectAccording to the report, the mask can remove viruses with an intermediate fiber layer made of nanofibers, and the first and second substrates are made of open-cell foam sheets, which increases breathability (reduces airflow resistance) and makes it less likely to feel stuffy even when worn for long periods of time. Furthermore, the use of open-cell foam sheets increases the stretch and flexibility of the mask, allowing it to conform well to the skin and preventing viruses and other contaminants from entering through gaps between the skin and the mask. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a partially cutaway perspective view of a virus removal filter according to one embodiment of the present invention. [Figure 2] 1 is a perspective view of a mask according to an embodiment of the present invention. [Figure 3] FIG. 3 is a perspective view showing the state in which two mask halves are stacked on top of each other in the mask of FIG. 2. [Figure 4] 3A to 3C are diagrams showing steps in manufacturing the mask of FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will now be described. Fig. 1 is a perspective view showing a virus removal filter 10 according to one embodiment of the present invention, with a second substrate 21 partially cut away.

[0018] The virus removal filter 10 is composed of a laminate of a first substrate 11, a second substrate 21, and an intermediate fiber layer 31 located between the first substrate 11 and the second substrate 21.

[0019] The first substrate 11 and the second substrate 21 are made of an open-cell foam sheet. The material of the open-cell foam sheet may be any foam with an open-cell structure, such as open-cell polyurethane (PUR) foam, open-cell polyethylene (PE) foam, or open-cell melamine foam. A more preferred open-cell foam is open-cell polyurethane (PUR) foam. Open-cell polyurethane foam has excellent elongation and strength, a high aperture ratio, and enhanced breathability. When used in a mask, it allows the mask to fit the face well and ensures good breathability. Open-cell polyurethane foams include ether-based and polyester-based foams, with polyester-based foams being more preferred due to their good elongation.

[0020] The open-cell polyurethane foam is preferably a membrane-removed flexible slab polyurethane foam. The membrane-removed flexible slab polyurethane foam is obtained by removing the cell membrane from a flexible slab polyurethane foam through a known membrane-removal treatment. Examples of membrane-removal treatments include a method of removing the cell membrane from a flexible slab polyurethane foam using a solvent or a method of removing the cell membrane by explosion. The flexible slab polyurethane foam is formed by slab foaming, in which polyurethane foaming raw material is discharged onto a conveyor belt and foamed continuously.

[0021] The number of cells (JIS K6400-1) of the open-cell foam sheet is preferably 40 to 110 cells / 25 mm. As the number of cells decreases, the breathability increases but the strength decreases. Conversely, as the number of cells increases, the breathability decreases but the strength increases. The density (JIS K7222) of the open-cell foam sheet is 10 to 85 kg / m. 3 When the density is low, flexibility and lightness are increased but strength is reduced, and conversely, when the density is high, flexibility and lightness are reduced but strength is increased.

[0022] The thicknesses of the first substrate 11 and the second substrate 21 may each be within the range of 0.5 to 2.5 mm. More preferably, the thickness of the first substrate is 1.3 to 2.5 mm, and the thickness of the second substrate is 0.5 to 1.5 mm. Furthermore, the total thickness of the laminate of the first substrate and the second substrate is preferably 4.0 mm or less. If the first substrate 11 and the second substrate 21 are too thin, their strength decreases; conversely, if they are too thick, their flexibility and breathability decrease. Furthermore, in this embodiment, it is preferable to make the thickness of the first substrate 11, on one side of which the intermediate fiber layer 31 is formed, greater than the thickness of the second substrate 21 to facilitate the formation of the intermediate fiber layer 31. When open-cell foams with different thicknesses on the front and back sides are used as a filter, it is preferable to use the thicker first substrate as the suction side and the thinner second substrate as the suction side. It is preferable to suck in dust particles and other contaminants through the thicker first substrate, remove them through the filter, and then suction air through the thinner second substrate.

[0023] The intermediate fiber layer 31 is made of nanofibers and is formed on one side of the first substrate 11 (the side facing the second substrate 21). The nanofibers can be formed by electrospinning. In this process, a polymer solution is directly sprayed from a nozzle onto one side of the first substrate 22, and a spider web-like nanofiber intermediate fiber layer 31 is formed in a state of being adhered to one side of the first substrate 11. The electrospinning process uses an apparatus consisting of a DC high-voltage power supply, an infusion pump, a stainless steel needle syringe, and a metal collector. The polymer solution is sprayed from the nozzle at the tip of the needle syringe. The nozzle and the metal collector are oppositely charged, and when the polymer solution is sprayed from the syringe, nanofiber fibers are deposited on the substrate 11 placed on the collector, forming a layer.

[0024] The nanofiber material may be any material that can be formed into nanofibers by electrospinning, including thermoplastic resins such as polystyrene, polycarbonate, poly(meth)acrylate, polyvinyl chloride, polyethylene terephthalate, nylon-6,6, and nylon-4,6; biodegradable polymers such as polyurethane, polyvinyl alcohol, polylactic acid, polycaprolactone, polyethylene glycol, polyethylene-vinyl acetate copolymer, polyethylene-vinyl alcohol copolymer, polyethylene oxide, and collagen; polyacrylonitrile, polyamide, polyaniline, paraamide, polyvinyl acetate, and acetylcellulose (acetate). Polyurethane is a particularly preferred material because it has good adhesion to one side of the first substrate 11 when forming the nanofibers by spraying and good elongation. The intermediate fiber layer 31 made of polyurethane nanofibers easily conforms to the elongation of the first substrate 11 and the second substrate 21, allowing the virus removal filter 10 to easily fit the face when used as a mask component.

[0025] The diameter of the nanofibers may be any diameter that falls within the definition of a nanofiber, specifically, 1 nanometer (nm) to 1 micrometer (μm), preferably 10 nanometers (nm) to 0.8 micrometers (μm), more preferably 10 nanometers (nm) to 0.5 micrometers (μm), and even more preferably 10 nanometers (nm) to 100 nanometers (nm). Note that if the nanofiber diameter is too small, viruses may pass through the nanofibers in the intermediate fiber layer 31, while if the nanofiber diameter is too large, the breathability of the intermediate fiber layer 31 may decrease. A more preferred diameter is 10 nanometers (nm) to 100 nanometers (nm).

[0026] The weight of the intermediate fiber layer 31 made of the nanofiber is not limited, but is preferably 0.10 to 0.80 g / m 2If the basis weight is reduced, the gaps between the nanofibers will become larger, which may allow viruses to pass between the nanofibers, and conversely, if the basis weight is increased, the gaps between the nanofibers will become smaller, which may reduce breathability.

[0027] A manufacturing example of the virus removal filter 10 is shown below. A long sheet of open-cell porous material is used as the first substrate, and BASF thermoplastic polyurethane pellets are dissolved in a solvent on top of it, and a nanofiber nonwoven fabric is laminated and spun onto it by electrospinning. The fiber diameter is adjusted to a predetermined diameter by adjusting the distance between the spinning nozzle and the long sheet, the discharge rate of the nanofiber raw material discharged from the nozzle, and the voltage. The spun urethane nanofiber intermediate layer is entangled with the long sheet of open-cell porous material. The long sheet is wound onto a roll, and the roll and the second substrate roll are attached to a flame welding device. The virus removal filter 10 is obtained by laminating and transporting the second substrate roll while applying a flame to the urethane nanofiber intermediate layer on the roll.

[0028] The virus removal filter 10 preferably has an elongation (JIS K6400-5) of 100 to 500% in order to provide a good fit to the face when used as a mask. Furthermore, the virus removal filter 10 preferably has an air permeability (JIS L1096 8.26.1 A method) of 30 (cm 3 / cm 2 ·sec) or more, and more preferably, the air permeability is 30 to 95 (cm 3 / cm 2 ·sec).

[0029] The virus removal performance of the virus removal filter 10 can be determined by the BFE capture rate (%). The BFE capture rate is a value measured in accordance with JIS L1912:1997 (Annex) (Test Methods for Medical Nonwoven Fabrics), and a higher BFE capture rate indicates no change in the total colony count of Staphylococcus aureus. That is, the BFE capture rate is the percentage obtained by subtracting the total colony count (B) when the sample was set from the total colony count (A) of the control, and dividing the difference by the total colony count (A) of the control. Bacteria capture efficiency BFE (%) = {(A) - (B)} ÷ (A) × 100 The virus removal filter 10 preferably has a BFE collection rate of 60 to 100%, more preferably 70 to 100%.

[0030] An embodiment of a mask using the virus removal filter 10 will be described with reference to the drawings. The mask 100 shown in Figures 2 and 3 covers part of the face including the mouth and nostrils, has ear loops 130 on both the left and right ends, and is made by joining two sheet-like mask halves 110, 110 together.

[0031] The mask half 110 is formed by dividing the mask 100 in half at the left-right middle position, and is constructed by punching out the virus removal filter 10 into a shape having openings 130 as ear loops at one end 110a and a curved portion 150 that bulges outward at the other end 110b. In the illustrated embodiment, as shown in Fig. 3, the mask half 110 has a shape in which the width (vertical width when in use) increases from approximately the middle position M1 of the mask half 110 in the left-right (lengthwise) direction toward the other end 110b where the curved portion 150 is formed.

[0032] The openings 130a of the ear hooks 130 are through-holes sized to allow ears to be inserted and hooked onto the ears when the mask 100 is worn on the face. The shape of the openings 130a is not particularly limited as long as they are large enough to allow ear insertion. Examples include holes of suitable shapes such as circular, rectangular, and oval. Furthermore, it is preferable that the distance d between the openings 130a and the outer periphery of the mask half 110 be 2 mm or more at its narrowest point, so that the ear hooks 130 are less likely to break near the ear hooks 130 when pulled.

[0033] The curved portion 150 is a portion that joins the two mask halves 110, 110. The curved portion 150 has an outwardly bulging curved shape (i.e., a substantially arcuate shape). Therefore, after the two mask halves 110 are joined at the curved portion 150, when the two mask halves 110, 110 are unfolded, the joined curved portion 150 bulges outward from the mask. Furthermore, the joined curved portion 150 is located at the left-right center of the mask 100, corresponding to the tip of the nose and the mouth when the mask 100 is worn on the face. Therefore, the outward bulging of the joined curved portion 150 causes the mask 100 to bulge outward at the nose, making it easier for the edge of the mask to fit snugly against the face near the bridge of the nose. This allows the periphery of the mask 100 to fit snugly against the face, creating space around the nostrils and mouth, making breathing easier. The curved portion 150 does not have to be entirely curved, and may be partially straight. In particular, if the portion from the bridge of the nose to the tip of the nose is partially straight, a better fit can be obtained.

[0034] The curved portions 150, 150 are joined by adhesive, welding, hot melt, etc. Welding methods include heat welding, vibration welding, ultrasonic welding, laser welding, etc. Joining by welding such as heat welding is particularly preferable because it does not require the use of solvents that pose health concerns, as do adhesives.

[0035] The manufacture of the mask 10 will be briefly explained with reference to FIG. 4. The mask 100 is manufactured by punching two mask halves 110, 110 from the virus removal filter 10, stacking the two mask halves 110, 110 as shown in FIG. 4 (4-1) and (4-2), and then joining the curved portions 150, 150 of the mask halves 110, 110 by adhesive or welding as shown in FIG. 4 (4-3) to form the mask 100. When joining the curved portions 150, 150 by thermal welding, this is done by sandwiching the curved portions 150, 150 of the stacked mask halves 110, 110 between hot plates. The temperature of the hot plates is set to a temperature at which the virus removal filters 10 constituting the mask halves 110, 110 can be thermally welded. Furthermore, when the virus removal filter 10 constituting the mask halves 150, 150 is configured such that the thickness of the first base material 11 is greater than the thickness of the second base material 21, it is preferable to join the mask halves 150, 150 so that the thicker first base material 11 is on the face side in order to improve the fit of the mask to the face. [Example]

[0036] An intermediate fiber layer made of nanofibers was directly spray-formed onto one side of a first substrate by electrospinning, and then a second substrate was welded onto the intermediate fiber layer by flame lamination to produce the virus removal filters of the following examples. The diameter of the nanofibers in the intermediate fiber layer was measured by diameter / length distribution measurement using a transmission or scanning electron microscope (TEM / SEM). The basis weight of the intermediate fiber layer was calculated by measuring the mass of the sample and converting it into per square meter.

[0037] Example 1 First substrate: De-filmed soft slab polyurethane foam (polyester-based), density 0.075 g / cm 3 , 80 cells / 25mm, Product name: MF-80A, Made by Inoac Corporation, Thickness: 1.5mm Second base material: 1mm thick soft slab polyurethane foam (polyester type) with the film of the first base material removed Middle fiber layer: Polyurethane nanofiber, diameter: 466 nm, basis weight: 0.13 g / m 2 A polyurethane resin solution was prepared by dissolving polyurethane resin in DMF (N,N-dimethylformamide). This solution was placed in a needle syringe and discharged onto a first substrate attached to a metal collector 15 cm from the nozzle at room temperature and atmospheric pressure with an applied voltage of 20 kV and a nozzle diameter of 0.4 mm. The first substrate and intermediate fiber layer were then laminated using an electrospinning device. A second substrate was then laminated onto the laminated first substrate and intermediate fiber layer. A flame welding device manufactured by Taiyo Rika Kogyo Co., Ltd. was used.

[0038] Example 2 First substrate: same as in Example 1 Second substrate: same as in Example 1 Middle fiber layer: Polyurethane nanofiber, diameter: 531 nm, basis weight: 0.25 g / m 2 A polyurethane resin solution was prepared by dissolving polyurethane resin in DMF (N,N-dimethylformamide). This solution was placed in a needle syringe and discharged onto a first substrate attached to a metal collector 15 cm from the nozzle at an applied voltage of 20 kV, a nozzle diameter of 0.4 mm, and room temperature and atmospheric pressure. The first substrate and intermediate fiber layer were then laminated using an electrospinning device. A second substrate was then laminated onto the laminated first substrate and intermediate fiber layer. A flame welding device manufactured by Taiyo Rika Kogyo Co., Ltd. was used.

[0039] Example 3 First substrate: same as in Example 1 Second substrate: same as in Example 1 Middle fiber layer: Polyurethane nanofiber, diameter: 443 nm, basis weight: 0.35 g / m 2 A polyurethane resin solution was prepared by dissolving polyurethane resin in DMF (N,N-dimethylformamide). This solution was placed in a needle syringe and discharged onto a first substrate attached to a metal collector placed 15 cm from the nozzle at an applied voltage of 20 kV, a nozzle diameter of 0.4 mm, and room temperature and atmospheric pressure. The first substrate and intermediate fiber layer were then laminated using an electrospinning device. A second substrate was then laminated onto the laminated first substrate and intermediate fiber layer. A flame welding device manufactured by Taiyo Rika Kogyo Co., Ltd. was used.

[0040] Example 4 First substrate: the same material as in Example 1, thickness 2.0 mm Second substrate: same as in Example 1 Middle fiber layer: Polyurethane nanofiber, diameter: 449 nm, basis weight: 0.14 g / m 2 A polyurethane resin solution was prepared by dissolving polyurethane resin in DMF (N,N-dimethylformamide). This solution was placed in a needle syringe and discharged onto a first substrate attached to a metal collector placed 15 cm from the nozzle at an applied voltage of 20 kV, a nozzle diameter of 0.4 mm, and room temperature and atmospheric pressure. The first substrate and intermediate fiber layer were then laminated using an electrospinning device. A second substrate was then laminated onto the laminated first substrate and intermediate fiber layer. A flame welding device manufactured by Taiyo Rika Kogyo Co., Ltd. was used.

[0041] Example 5 First substrate: De-filmed soft slab polyurethane foam (polyester-based), density 0.09 g / cm 3 , Cell count 105 / 25mm, Product name: MF-DS, Inoac Corporation, Thickness 1.5mm Second base material: 1mm thick soft slab polyurethane foam (polyester type) with the film of the first base material removed Middle fiber layer: Polyurethane nanofiber, diameter: 458 nm, basis weight: 0.28 g / m 2 A polyurethane resin solution was prepared by dissolving polyurethane resin in DMF (N,N-dimethylformamide). This solution was placed in a needle syringe and discharged onto a first substrate attached to a metal collector placed 15 cm from the nozzle at an applied voltage of 20 kV, a nozzle diameter of 0.4 mm, and room temperature and atmospheric pressure. The first substrate and intermediate fiber layer were then laminated using an electrospinning device. A second substrate was then laminated onto the laminated first substrate and intermediate fiber layer. A flame welding device manufactured by Taiyo Rika Kogyo Co., Ltd. was used.

[0042] Example 6 First substrate: De-filmed soft slab polyurethane foam (polyester-based), density 0.03 g / cm 3 60 cells / 25mm, Product name: MF-60, Inoac Corporation, Thickness: 1.5mm Second base material: 1mm thick soft slab polyurethane foam (polyester type) with the film of the first base material removed Middle fiber layer: Polyurethane nanofiber, diameter: 317 nm, basis weight: 0.19 g / m 2 A polyurethane resin solution was prepared by dissolving polyurethane resin in DMF (N,N-dimethylformamide). This solution was placed in a needle syringe and discharged onto a first substrate attached to a metal collector placed 15 cm from the nozzle at an applied voltage of 20 kV, a nozzle diameter of 0.4 mm, and room temperature and atmospheric pressure. The first substrate and intermediate fiber layer were then laminated using an electrospinning device. A second substrate was then laminated onto the laminated first substrate and intermediate fiber layer. A flame welding device manufactured by Taiyo Rika Kogyo Co., Ltd. was used.

[0043] Example 7 First substrate: De-filmed soft slab polyurethane foam (polyether-based), density 0.025 g / cm 3 , Number of cells: 40 / 25mm, Product name: EL-62, Made by Inoac Corporation, Thickness: 1.5mm Second base material: 1mm thick soft slab polyurethane foam (polyether type) with the film removed from the first base material Middle fiber layer: Polypropylene nanofiber, diameter: 503 nm, basis weight: 0.11 g / m 2 A polyurethane resin solution was prepared by dissolving polyurethane resin in DMF (N,N-dimethylformamide). This solution was placed in a needle syringe and discharged onto a first substrate attached to a metal collector placed 15 cm from the nozzle at an applied voltage of 20 kV, a nozzle diameter of 0.4 mm, and room temperature and atmospheric pressure. The first substrate and intermediate fiber layer were then laminated using an electrospinning device. A second substrate was then laminated onto the laminated first substrate and intermediate fiber layer. A flame welding device manufactured by Taiyo Rika Kogyo Co., Ltd. was used.

[0044] Example 8 First substrate: open-cell polyethylene foam, density 0.03 g / cm 3 , Cell count 35 / 25mm, Thickness 1.5mm, Product name: P·E Light, Manufactured by Inoac Corporation Second base material: 1mm thick open-cell polyethylene foam of the first base material Middle fiber layer: Polyurethane nanofiber, diameter: 448 nm, basis weight: 0.20 g / m 2 A polyurethane resin solution was prepared by dissolving polyurethane resin in DMF (N,N-dimethylformamide). This solution was placed in a needle syringe and discharged onto a first substrate attached to a metal collector placed 15 cm from the nozzle at an applied voltage of 20 kV, a nozzle diameter of 0.4 mm, and room temperature and atmospheric pressure. The first substrate and intermediate fiber layer were then laminated using an electrospinning device. A second substrate was then laminated onto the laminated first substrate and intermediate fiber layer. A flame welding device manufactured by Taiyo Rika Kogyo Co., Ltd. was used.

[0045] The following comparative examples were prepared. Comparison Example 1 A commercially available SMS nonwoven mask was used, with a meltblown microweb nonwoven fabric layer made of polyolefin as the middle layer, and spunbond nonwoven fabric laminated on both sides of the middle layer, with a total thickness of 0.6 mm and a fiber diameter of 7.9 μm.

[0046] Comparison Example 2 The first substrate in Example 1 was made of a soft slab polyurethane foam (polyester-based) with a density of 0.075 g / cm. 3 The cell count was 80 / 25mm, product name: MF-80A, manufactured by Inoac Corporation, and the cell was configured as a single layer with a thickness of 2mm.

[0047] Comparative Example 3 The first substrate in Example 1 was made of a soft slab polyurethane foam (polyester-based) with a density of 0.075 g / cm. 3 The cell count was 80 / 25mm, product name: MF-80A, manufactured by Inoac Corporation, and the thickness was reduced to 8mm, and the thickness was reduced to 2mm by heat pressing to form a single layer.

[0048] Comparative Example 4 The first substrate in Example 1 was made of a soft slab polyurethane foam (polyester-based) with a density of 0.075 g / cm. 3 , Cell count: 80 / 25mm, Product name: MF-80A, Manufactured by Inoac Corporation, 2mm thick substrate, with polyolefin microfiber, diameter: 7.8μm, basis weight: 48g / m on one side of the substrate. 2 was directly spray-formed by electrospinning.

[0049] Comparative Example 5 The first substrate in Example 1 was made of a soft slab polyurethane foam (polyester-based) with a density of 0.075 g / cm. 3 , Cell count: 80 / 25mm, Product name: MF-80A, Manufactured by Inoac Corporation, 2mm thick substrate, with polyolefin microfiber, diameter: 8.0μm, basis weight: 135g / m on one side of the substrate 2 was directly spray-formed by electrospinning.

[0050] For each of the examples and comparative examples, the BFE capture rate (%) and air permeability (cm 3 ·cm 2 ·sec), rigidity, and elongation (%) were measured. The BFE capture rate (%) is measured in accordance with JIS L1912:1997 (Appendix) (Test method for medical nonwoven fabrics). The air permeability was measured in accordance with JIS L1096 8.26.1 Method A (Fragile method), and the elongation was measured in accordance with JIS K 6400-5, Method for Determining Elongation. The measurement results and evaluation are shown in Table 1.

[0051] [Table 1]

[0052] In Examples 1 to 8, the BFE collection rate was 65 to 92% and the air permeability was 30 to 95 cm 3 / cm 2 The BFE capture efficiency and breathability were both good, falling within the range of 1.5 sec. The elongation was also good, ranging from 180 to 421%.

[0053] As described above, the virus removal filters of each Example have sufficient breathability and virus removal performance, and also have good stretch. When used to form a mask, the filters cause little breathlessness even when used for long periods of time and have virus removal performance.

[0054] On the other hand, Comparative Example 1, which is made of a laminate of microfiber nonwoven fabrics, had a high BFE collection rate, but low breathability and elongation. Comparative Example 2, which consisted of a single layer of stripped flexible slab polyurethane foam, had a low BFE capture rate. Comparative Example 3, in which the film-removed flexible slab polyurethane foam was hot-pressed, had a medium BFE collection rate of 47.7% and low air permeability. Microfiber is applied to the soft slab polyurethane foam with a membrane-removed weight of 48g / m 2 In Comparative Example 4, which was laminated with the above-mentioned material, the BFE collection rate was medium at 49.5% and the rigidity was also low. Microfiber is applied to the soft slab polyurethane foam with a membrane removal rate of 135g / m 2Comparative Example 5, in which the laminate was made of 100% BFE, had a high BFE collection rate but low air permeability. As described above, each of the comparative examples had a low BFE collection rate or low breathability, and there was no comparative example that had both a high BFE collection rate and high breathability. [Explanation of symbols]

[0055] 10. Virus removal filters 11 First base material 21 Second base material 31 Intermediate fiber layer 100 masks 110 Half mask 130 Ear hook 130a opening 150 curved section

Claims

1. a first substrate made of an open-cell foam sheet; a second substrate made of an open-cell foam sheet; an intermediate fibrous layer positioned between the first substrate and the second substrate; In a filter composed of a laminate of The BFE collection rate is 60% or more, and the air permeability is 30 cm ３ / cm ２ sec or more (excluding those containing activated carbon in the intermediate fiber layer), A method for producing a filter, comprising the step of welding the second substrate onto the intermediate fiber layer by flame lamination using a flame welding device.

2. The intermediate fiber layer has a basis weight of 0.10 to 0.80 g / m ２ 2. The method for producing a filter according to claim 1, wherein

3. A method for manufacturing a mask, comprising a step of punching the filter obtained by the method for manufacturing a filter according to claim 1 or 2.

4. a first substrate made of an open-cell foam sheet; a second substrate made of an open-cell foam sheet; an intermediate fibrous layer positioned between the first substrate and the second substrate; In a mask that is composed only of the laminate of The BFE collection rate is 60% or more, and the air permeability is 30 cm ３ / cm ２ A method for manufacturing a mask, characterized in that the time is 20 seconds or more, A method for manufacturing a mask, comprising a step of welding the second substrate onto the intermediate fiber layer by flame lamination using a flame welding device.

5. The intermediate fiber layer has a basis weight of 0.10 to 0.80 g / m ２ 5. The method for manufacturing a mask according to claim 4, wherein

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