JP2021120499A - Virus removing filter and mask using the same - Google Patents

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

The present invention relates to a virus removing filter and a mask using the same.

Conventionally, as a mask, there are a mask made of gauze (Patent Document 1) and a mask made of urethane foam (Patent Document 2). However, the mask made of gauze or urethane foam had a coarse mesh and was not sufficient in virus removal performance.

Further, a mask made of a composite fabric of a nanofiber non-woven fabric layer and at least one layer of cloth has been proposed (Patent Document 3). However, this mask is intended to ensure wind resistance, moisture permeability and elasticity, and does not disclose virus removal. Furthermore, since the non-woven fabric is used as the base material, the adhesion to the face is inferior, and there is a high possibility that the removal rate of the virus will be lowered.

In addition, masks that claim to remove viruses have also appeared, but the size of the virus is 1 μm or less, and if the mesh of the filter that makes up the mask is made finer, the air permeability will decrease, and when used as a mask for a long time, Some people feel stuffy.

As a mask for the purpose of efficiently blocking viruses and bacteria and inactivating and killing the collected viruses and bacteria, a mask in which an inorganic porous substance is supported on a nanofiber non-woven fabric and laminated with a microfiber non-woven fabric. Is disclosed (Patent Document 4). However, since the microfiber itself is thick in this mask, the porosity per unit area is extremely low, the air permeability is lowered, and there is a risk of feeling stuffy after long-term use. Further, when a non-woven fabric is used as the base material of the mask, the non-woven fabric has low extensibility and flexibility, so that the non-woven fabric has insufficient followability to the skin, and a virus or the like may invade through the gap between the skin and the mask.

Jitsukaisho 53-4799 Japanese Unexamined Patent Publication No. 2008-136754 Japanese Unexamined Patent Publication No. 2014-234561 Japanese Unexamined Patent Publication No. 2008-188082

The present invention has been made in view of the above points, and an object of the present invention is to provide a virus removing filter having sufficient air permeability and virus removing performance, and a mask using the same.

The invention of claim 1 is a first base material made of an open cell foam sheet, an intermediate fiber layer made of nanofibers formed on one side of the first base material, and open cells laminated on the intermediate fiber layer. The present invention relates to a virus removing filter composed of a second base material made of a foam sheet.

The invention of claim 2 is characterized in that, in claim 1, the open cell foam sheet of the first base material and the second base material is made of a defilmed soft slab polyurethane foam sheet.

The invention of claim 3 is characterized in that, in claim 1 or 2, the nanofiber is polyurethane.

In the invention of claim 4, two mask halves having an opening as an ear hook on one end side and a curved shape portion bulging outward on the other end side are any of claims 1 to 3. The present invention relates to a mask composed of the virus removing filter according to the first item, in which the two mask halves are joined at the curved shape portion.

According to the invention of claim 1, since it has an intermediate fiber layer made of nanofibers, nanolevel viruses can be efficiently removed. Further, by using the open cell foam sheet for the first base material and the second base material, the air permeability of the virus removal filter is increased, and clogging and deterioration of air permeability are unlikely to occur even if the filter is used for a long time. can.

According to the invention of claim 2, since the open cell foam sheet is made of a soft slab polyurethane foam sheet from which the film has been removed, high air permeability can be ensured.

According to the invention of claim 3, since the nanofiber is made of polyurethane, when the nanofiber is formed on one side of the first base material, the adhesiveness between the first base material and the nanofiber is high and the elasticity is high. A good nanofiber layer is obtained.

According to the invention of claim 4, the mask can remove the virus by the intermediate fiber layer made of nanofibers, and the first base material and the second base material are composed of the open cell foam sheet, so that the mask has a high air permeability. (Lower ventilation resistance), making it difficult to feel stuffy even after long-term use. Further, the use of the open cell foam sheet enhances the extensibility and flexibility of the mask, improves the followability to the skin, and prevents viruses and the like from invading through the gap between the skin and the mask.

It is a perspective view which shows by cutting out a part of the virus removal filter of one Embodiment of this invention. It is a perspective view of the mask which concerns on one Embodiment of this invention. It is a perspective view which shows the state in which the two mask halves are overlapped in the mask of FIG. It is a figure which shows the process at the time of manufacturing the mask of FIG.

Hereinafter, embodiments of the present invention will be described. FIG. 1 is a perspective view showing a part of the second base material 21 of the virus removing filter 10 according to the embodiment of the present invention.

The virus removing filter 10 is composed of a laminate of a first base material 11, a second base material 21, and an intermediate fiber layer 31 located between the first base material 11 and the second base material 21. ing.

The first base material 11 and the second base material 21 are made of an open cell foam sheet. The material of the open-cell foam sheet may be any foam having an open-cell structure, and examples thereof include open-cell polyurethane (PUR) foam, open-cell polyethylene (PE) foam, and open-cell melamine foam. .. A more preferred open cell foam is an open cell polyurethane (PUR) foam. The open-cell polyurethane foam has excellent elongation and strength, a high aperture ratio, and can enhance breathability. Therefore, when used for a mask, the mask can be fitted to the face and has good ventilation. Sex can be ensured. There are ether type and polyester type in the open cell polyurethane foam, but the polyester type which can obtain good elongation is more preferable.

Further, the open-cell polyurethane foam is preferably a defilmed soft slab polyurethane foam. The defilmed soft slab polyurethane foam is obtained by subjecting the soft slab polyurethane foam to a known demembrane treatment to remove the cell film. As the film removing treatment, there are a method of removing the cell film of the soft slab polyurethane foam with a solvent, a method of removing the cell film by an explosion, and the like. Further, the soft slab polyurethane foam is formed by slab foaming in which a polyurethane foaming raw material is discharged onto a conveyor belt and continuously foamed.

The number of cells (JIS K6400-1) of the open cell foam sheet is preferably 40 to 110 cells / 25 mm. When the number of cells is small, the air permeability is increased but the strength is decreased. On the contrary, when the number of cells is large, the air permeability is decreased but the strength is increased. The density of the open cell foam sheet (JIS K7222) is preferably ^{10 to 85 kg / m 3.} When the density is low, the flexibility and lightness are increased, but the strength is lowered. On the contrary, when the density is high, the flexibility and lightness are inferior, but the strength is increased.

The thickness of the first base material 11 and the second base material 21 may be in the range of 0.5 to 2.5 mm, respectively. More preferably, the thickness of the first base material is 1.3 to 2.5 mm, and the thickness of the second base material is 0.5 to 1.5 mm. Further, the thickness of the laminated first base material and the second base material is preferably 4.0 mm or less. If the thickness of the first base material 11 and the second base material 21 is too thin, the strength is lowered, and conversely, if the thickness is too thick, the flexibility and breathability are deteriorated. Further, in the present embodiment, the thickness of the first base material 11 on which the intermediate fiber layer 31 is formed on one side is made larger than the thickness of the second base material 21 to facilitate the formation of the intermediate fiber layer 31. preferable. When the open cell foams having different thicknesses on the front and back surfaces are used as a filter, it is preferable that the thick first base material is the suction side and the thin second base material side is the suction side. It is preferable to suck in dust such as fine particles from the thick first base material, remove it with a filter, and then suck air from the thin second base material side.

The intermediate fiber layer 31 is made of nanofibers and is formed on one side of the first base material 11 (the side facing the second base material 21). The formation of the nanofibers can be performed by an electrospinning method. At that time, the polymer solution is directly sprayed from the nozzle onto one side of the first base material 22, and the intermediate fiber layer 31 of the nanofibers in the shape of a spider nest is formed in a state of being adhered to one side of the first base material 11. do. The electrolytic spinning method uses a device consisting of a DC high voltage power supply, an infusion pump, a stainless needle syringe, and a metal collector. The polymer solution is ejected from the tip nozzle of the needle syringe. The nozzle and the metal collector are charged at the opposite poles, and when the polymer solution is sprayed from the syringe, nanofiber fibers are deposited on the base material 11 placed on the collector to form a layer.

The material of the nanofibers may be one capable of forming nanofibers by an electrolytic spinning method, for example, polystyrene, polycarbonate, poly (meth) acrylate, polyvinyl chloride, polyethylene terephthalate, nylon-6,6, nylon-4, Thermoplastic resins such as 6, polyurethane, polyvinyl alcohol, polylactic acid, polycaprolactone, polyethylene glycol, polyethylene-vinyl acetate copolymers, polyethylene-vinyl alcohol copolymers, polyethylene oxide, biodegradable polymers such as collagen, Examples thereof include polyacrylonitrile, polyamide, polyaniline, paraamide, polyvinyl acetate, acetylcellulose (acetate) and the like. In particular, polyurethane is a particularly preferable material because it has good adhesiveness to one side of the first base material 11 and has good elongation when the nanofibers are spray-formed. The intermediate fiber layer 31 made of polyurethane nanofibers has good followability to the elongation of the first base material 11 and the second base material 21, and when the virus removing filter 10 is used as a constituent member of the mask, the mask becomes a face. Easy to fit in.

The diameter of the nanofiber may be any diameter as defined by the nanofiber, specifically, 1 nanometer (nm) to 1 micrometer (μm), preferably 10 nanometer (nm) to 0.8. It is micrometer (μm), more preferably 10 nanometers (nm) to 0.5 micrometer (μm), and even more preferably 10 nanometers (nm) to 100 nanometers (nm). If the diameter of the nanofibers is too small, the virus may pass between the nanofibers of the intermediate fiber layer 31, and conversely, if the diameter of the nanofibers is too large, the air permeability of the intermediate fiber layer 31 decreases. .. More preferred diameters are from 10 nanometers (nm) to 100 nanometers (nm).

The basis weight of the intermediate fiber layer 31 made of the nanofibers is not limited, but is preferably ^{0.10 to 0.80 g / m 2.} If the basis weight is small, the nanofiber spacing becomes large and the virus may pass between the nanofibers. Conversely, if the basis weight is large, the nanofiber spacing becomes small and the air permeability decreases. become.

An example of manufacturing the virus removing filter 10 is shown below. A long sheet of open cell porous material for the first base material is used, a thermoplastic polyurethane pellet manufactured by BASF is dissolved in a solvent, and a nanofiber non-woven fabric is laminated and spun by an electrolytic spinning method. The fiber diameter is adjusted to a predetermined wire diameter according to the distance between the spinning nozzle and the long sheet, and the discharge amount and voltage of the nanofiber raw material discharged from the nozzle. The spun urethane nanofiber intermediate layer is entwined with the long sheet of the open cell porous body. The long sheet is wound on a roll, the roll and the roll of the second base material are attached to the flame welding device, and the roll of the second base material is applied while irradiating the urethane nanofiber intermediate layer of the roll with flame. The virus removing filter 10 can be obtained by laminating and transporting the above.

The virus removing filter 10 preferably has an elongation (JIS K6400-5) of 100 to 500% in order to improve the fit to the face when a mask is formed. Further, the virus removing filter 10 has an air permeability (JIS L1096 8.26.1 A method) of 30 (cm ³ / cm ² · sec) or more in order to prevent suffocation when a mask is formed. Is preferable, and the air permeability is more preferably 30 to 95 (cm ³ / cm ² · sec).

The virus removal performance of the virus removal filter 10 can be judged by the BFE collection rate (%). The BFE collection rate is a value measured according to JIS L1912: 1997 (Appendix) (medical non-woven fabric test method), and the larger the value, the more the total number of Staphylococcus aureus colonies does not change. .. That is, it refers to the percentage of the value obtained by subtracting the total number of colonies (B) when the sample is set from the total number of colonies (A) of the control and dividing the difference by the total number of colonies (A) of the control.
Bacterial collection efficiency BFE (%) = {(A)-(B)} ÷ (A) × 100
The virus removing filter 10 preferably has a BFE collection rate of 60 to 100%, more preferably 70 to 100%.

An embodiment of a mask using the virus removing filter 10 will be described with reference to the drawings. The mask 100 shown in FIGS. 2 and 3 covers a part of the face including the mouth and nostrils, and has ear hooks 130 on both the left and right ends, and two sheet-shaped mask halves 110 and 110 are attached. It consists of joined ones.

The mask half body 110 has a shape divided into two at an intermediate position in the left-right direction of the mask 100, and an opening 130 as an ear hook is formed on one end 110a side and bulges outward on the other end 110b side. The virus removing filter 10 is punched into a shape having a curved shape portion 150. In the illustrated embodiment, as shown in FIG. 3, the width (from the substantially intermediate position M1 on the left and right (length direction) of the mask semifield 110 toward the other end 110b where the curved shape portion 150 is formed ( It has a shape with an enlarged vertical width when used).

The opening 130a as the ear hook 130 is formed of a through hole, and is formed in a size such that the ear is inserted and hooked on the ear when the mask 100 is attached to the face. The shape of the opening 130a is not particularly limited as long as it is a hole having a size that allows the ear to be inserted. For example, holes having an appropriate shape such as a circle, a quadrangle, and an ellipse may be mentioned. Further, the distance d between the opening 130a and the outer peripheral edge of the mask half body 110 is set to 2 mm or more at the narrowest portion, and when the ear hook 130 is pulled, it is difficult to break near the ear hook 130. It is preferable to do so.

The curved shape portion 150 is a portion that joins the two mask halves 110 and 110. Since the curved shape portion 150 has a curved shape that bulges outward (that is, a substantially arc shape), the two masks are joined after the two mask halves 110 are joined by the curved shape portion 150. When the halves 110 and 110 are unfolded, the joined curved shape portion 150 bulges outward from the mask. Further, since the joined curved shape portion 150 is located at an intermediate position between the left and right sides of the mask 100 and at a position corresponding to the tip of the nose and the mouth when the mask 100 is attached to the face, the joined curved shape portion 150 is provided. The outward bulge of the 150 causes the mask 100 to bulge outward at the position of the nose, and the edge of the mask easily adheres to the face in the vicinity of the nasal column. Therefore, the peripheral edge of the mask 100 is in close contact with the face, and a space is formed around the nostrils and the mouth, which facilitates breathing. The curved shape portion 150 may not have a curved shape at all, or may have a linear shape at a part. In particular, if a part of the portion that comes into contact with the tip of the nose from the nasal column is straight, a better wearing feeling can be obtained.

The joining of the curved shaped portions 150, 150 is performed by an adhesive, welding, hot melt, or the like. Welding includes heat welding, vibration welding, ultrasonic welding, laser welding and the like. In particular, joining by welding such as heat welding is preferable because it is not necessary to use a solvent that is concerned about health such as an adhesive.

The production of the mask 10 will be briefly described with reference to FIG. In the production of the mask 100, two mask halves 110 and 110 are formed by punching from the virus removing filter 10, and the two mask halves 110 and 110 are formed in FIGS. 4 (4-1) and (4). -2) are stacked, and as shown in (4-3) of FIG. 4, the curved shaped portions 150 and 150 of the mask halves 110 and 110 are joined by an adhesive or welding to obtain the mask 100. When the curved shape portions 150 and 150 are joined by heat welding, the curved shape portions 150 and 150 of the overlapped mask halves 110 and 110 are sandwiched between hot plates. The temperature of the hot plate at that time is set to a temperature at which the virus removing filters 10 constituting the mask semifields 110 and 110 can be heat-welded. Further, when the virus removing filter 10 constituting the mask semifields 150, 150 has a structure in which the thickness of the first base material 11 is larger than the thickness of the second base material 21, the face of the mask is covered. In order to improve the fit, it is preferable to join the mask halves 150 and 150 so that the first base material 11 having a large thickness is on the face side.

An intermediate fiber layer made of nanofibers is directly sprayed onto one side of the first base material by an electric field spinning method, and then the second base material is welded onto the intermediate fiber layer by frame lamination to form the viruses of the following examples. A filter for removal was created. The diameter of the nanofibers in the intermediate fiber layer was measured by measuring the diameter and length distribution with a transmission electron microscope (TEM / SEM). The basis weight of the intermediate fiber layer was calculated per square meter by measuring the mass of the sample.

・ Example 1
First base material: Defilmed soft slab polyurethane foam (polyester type), density 0.075 g / cm ³ , number of cells 80/25 mm, product name; MF-80A, manufactured by Inoac Corporation, thickness 1.5 mm
Second base material: Soft slab polyurethane foam (polyester type) from which the film was removed from the first base material has a thickness of 1 mm. Intermediate fiber layer: Polyurethane nanofibers, diameter: 466 nm, grain size: 0.13 g / m ²
A polyurethane resin solution was prepared by dissolving the polyurethane resin in DMF (N, N-dimethylformamide). This solution is put into a needle syringe and discharged onto a first base material mounted on a metal collector at a distance of 15 cm from the nozzle at an applied voltage of 20 KV, a nozzle diameter of 0.4 mm, and room temperature at atmospheric pressure. The first base material and the intermediate fiber layer were laminated. Further, the second base material is laminated on the laminated first base material and the intermediate fiber layer. A flame welding device manufactured by Taiyo Rika Kogyo Co., Ltd. was used.

-Example 2
First base material: same as Example 1 Second base material: same as Example 1 Intermediate fiber layer: Polyurethane nanofiber, diameter: 531 nm, basis weight: 0.25 g / m ²
A polyurethane resin solution was prepared by dissolving the polyurethane resin in DMF (N, N-dimethylformamide). This solution is put into a needle syringe and discharged onto a first base material mounted on a metal collector at a distance of 15 cm from the nozzle at an applied voltage of 20 KV, a nozzle diameter of 0.4 mm, and room temperature at atmospheric pressure. The first base material and the intermediate fiber layer were laminated. Further, the second base material is laminated on the laminated first base material and the intermediate fiber layer. A flame welding device manufactured by Taiyo Rika Kogyo Co., Ltd. was used.

・ Example 3
First base material: same as Example 1 Second base material: same as Example 1 Intermediate fiber layer: Polyurethane nanofiber, diameter: 443 nm, basis weight: 0.35 g / m ²
A polyurethane resin solution was prepared by dissolving the polyurethane resin in DMF (N, N-dimethylformamide). This solution is put into a needle syringe and discharged onto a first base material mounted on a metal collector installed at a distance of 15 cm from the nozzle at an applied voltage of 20 KV, a nozzle diameter of 0.4 mm, and room temperature at atmospheric pressure, and electrolyzed. The first base material and the intermediate fiber layer were laminated by a spinning device. Further, the second base material is laminated on the laminated first base material and the intermediate fiber layer. A flame welding device manufactured by Taiyo Rika Kogyo Co., Ltd. was used.

・ Example 4
First base material: Same material as in Example 1 and thickness 2.0 mm
Second base material: Same as Example 1. Intermediate fiber layer: Polyurethane nanofiber, diameter: 449 nm, basis weight: 0.14 g / m ²
A polyurethane resin solution was prepared by dissolving the polyurethane resin in DMF (N, N-dimethylformamide). This solution is put into a needle syringe and discharged onto a first base material mounted on a metal collector installed at a distance of 15 cm from the nozzle at an applied voltage of 20 KV, a nozzle diameter of 0.4 mm, and room temperature at atmospheric pressure, and electrolyzed. The first base material and the intermediate fiber layer were laminated by a spinning device. Further, the second base material is laminated on the laminated first base material and the intermediate fiber layer. A flame welding device manufactured by Taiyo Rika Kogyo Co., Ltd. was used.

・ Example 5
First base material: Defilmed soft slab polyurethane foam (polyester type), density 0.09 g / cm ³ , number of cells 105/25 mm, product name; MF-DS, manufactured by Inoac Corporation, thickness 1.5 mm
Second base material: Soft slab polyurethane foam (polyester type) from which the film was removed from the first base material has a thickness of 1 mm. Intermediate fiber layer: Polyurethane nanofibers, diameter: 458 nm, grain size: 0.28 g / m ²
A polyurethane resin solution was prepared by dissolving the polyurethane resin in DMF (N, N-dimethylformamide). This solution is put into a needle syringe and discharged onto a first base material mounted on a metal collector installed at a distance of 15 cm from the nozzle at an applied voltage of 20 KV, a nozzle diameter of 0.4 mm, and room temperature at atmospheric pressure, and electrolyzed. The first base material and the intermediate fiber layer were laminated by a spinning device. Further, the second base material is laminated on the laminated first base material and the intermediate fiber layer. A flame welding device manufactured by Taiyo Rika Kogyo Co., Ltd. was used.

-Example 6
First base material: Defilmed soft slab polyurethane foam (polyester type), density 0.03 g / cm ³ , number of cells 60/25 mm, product name; MF-60, manufactured by Inoac Corporation, thickness 1.5 mm
Second base material: Soft slab polyurethane foam (polyester type) from which the film was removed from the first base material has a thickness of 1 mm. Intermediate fiber layer: Polyurethane nanofibers, diameter: 317 nm, grain size: 0.19 g / m ²
A polyurethane resin solution was prepared by dissolving the polyurethane resin in DMF (N, N-dimethylformamide). This solution is put into a needle syringe and discharged onto a first base material mounted on a metal collector installed at a distance of 15 cm from the nozzle at an applied voltage of 20 KV, a nozzle diameter of 0.4 mm, and room temperature at atmospheric pressure, and electrolyzed. The first base material and the intermediate fiber layer were laminated by a spinning device. Further, the second base material is laminated on the laminated first base material and the intermediate fiber layer. A flame welding device manufactured by Taiyo Rika Kogyo Co., Ltd. was used.

-Example 7
First base material: Defilmed soft slab polyurethane foam (polyether type), density 0.025 g / cm ³ , number of cells 40/25 mm, product name; EL-62, manufactured by Inoac Corporation, thickness 1.5 mm
Second base material: Soft slab polyurethane foam (polyether type) from which the film was removed from the first base material has a thickness of 1 mm. Intermediate fiber layer: Polypropylene nanofiber, diameter: 503 nm, grain size: 0.11 g / m ²
A polyurethane resin solution was prepared by dissolving the polyurethane resin in DMF (N, N-dimethylformamide). This solution is put into a needle syringe and discharged onto a first base material mounted on a metal collector installed at a distance of 15 cm from the nozzle at an applied voltage of 20 KV, a nozzle diameter of 0.4 mm, and room temperature at atmospheric pressure, and electrolyzed. The first base material and the intermediate fiber layer were laminated by a spinning device. Further, the second base material is laminated on the laminated first base material and the intermediate fiber layer. A flame welding device manufactured by Taiyo Rika Kogyo Co., Ltd. was used.

-Example 8
First base material: open cell polyethylene foam, density 0.03 g / cm ³ , number of cells 35/25 mm, thickness 1.5 mm, product name; PE Light, manufactured by Inoac Corporation Second base material: First base material Intermediate fiber layer: polyurethane nanofiber, diameter: 448 nm, grain size: 0.20 g / m ²
A polyurethane resin solution was prepared by dissolving the polyurethane resin in DMF (N, N-dimethylformamide). This solution is put into a needle syringe and discharged onto a first base material mounted on a metal collector installed at a distance of 15 cm from the nozzle at an applied voltage of 20 KV, a nozzle diameter of 0.4 mm, and room temperature at atmospheric pressure, and electrolyzed. The first base material and the intermediate fiber layer were laminated by a spinning device. Further, the second base material is laminated on the laminated first base material and the intermediate fiber layer. A flame welding device manufactured by Taiyo Rika Kogyo Co., Ltd. was used.

The following comparative example was created.
・ Comparative example 1
A commercially available SMS non-woven fabric mask in which a meltblown microweb non-woven fabric layer made of polyolefin was used as an intermediate layer and both sides of the intermediate layer were laminated with a spunbonded non-woven fabric, a total thickness of 0.6 mm, and a fiber diameter of 7.9 μm was used.

・ Comparative example 2
Defilmed soft slab polyurethane foam (polyester type) used in the first substrate of Example 1, density 0.075 g / cm ³ , number of cells 80/25 mm, product name; MF-80A, manufactured by Inoac Corporation Was composed of a single layer having a thickness of 2 mm.

・ Comparative example 3
Defilmed soft slab polyurethane foam (polyester type) used in the first substrate of Example 1, density 0.075 g / cm ³ , number of cells 80/25 mm, product name; MF-80A, manufactured by Inoac Corporation Was formed into a single layer having a thickness of 8 mm and a thickness of 2 mm by hot pressing.

・ Comparative example 4
Defilmed soft slab polyurethane foam (polyester type) used in the first substrate of Example 1, density 0.075 g / cm ³ , number of cells 80/25 mm, product name; MF-80A, manufactured by Inoac Corporation. A thickness of 2 mm was used as a base material, and polyolefin microfibers having a diameter of 7.8 μm and a grain size of 48 g / m ² were directly sprayed onto one side of the base material by an electrospinning method.

・ Comparative example 5
Defilmed soft slab polyurethane foam (polyester type) used in the first substrate of Example 1, density 0.075 g / cm ³ , number of cells 80/25 mm, product name; MF-80A, manufactured by Inoac Corporation. A thickness of 2 mm was used as a base material, and polyolefin microfibers having a diameter of 8.0 μm and a grain size of 135 g / m ² were directly sprayed onto one side of the base material by an electrospinning method.

BFE collection rate (%), air permeability (cm ³ · cm ² · sec), rigidity, and elongation (%) were measured for each of the Examples and Comparative Examples.
The method for measuring the BFE collection rate (%) is JIS L1912: 1997 (Appendix) (medical non-woven fabric test method).
The air permeability was measured according to JIS L1096 8.26.1 A method (Frazier method), the elongation was measured according to JIS K 6400-5, and the elongation was determined.
The measurement results and evaluations are shown in Table 1.

In Examples 1 to 8, the BFE collection rate is in the range of 65 to 92% and the air permeability is in the range of ³⁰ to 95 cm 3 / cm ² · sec, and both the BFE collection rate and the air permeability are good. there were. Moreover, the elongation was good at 180 to 421%.

As described above, the virus removal filter of each example has sufficient air permeability, has virus removal performance, has good elongation, and is used for a long time when a mask is constructed. However, it is less stuffy and has the ability to remove viruses.

On the other hand, Comparative Example 1 composed of a laminated microfiber non-woven fabric had a high BFE collection rate, but had low air permeability and low elongation. Comparative Example 2 composed of a single layer of defilmed soft slab polyurethane foam. The BFE collection rate was low.
In Comparative Example 3 in which the defilmed soft slab polyurethane foam was heat-pressed, the BFE collection rate was medium at 47.7%, and the air permeability was also low.
In Comparative Example 4 in which microfibers were laminated on the defilmed soft slab polyurethane foam at a basis weight of 48 g / m ² , the BFE collection rate was medium at 49.5% and the rigidity was low.
In Comparative Example 5 in which microfibers were laminated on the defilmed soft slab polyurethane foam with a basis weight of 135 g / m ² , the BFE collection rate was high, but the air permeability was low.
As described above, each of the comparative examples had a low BFE collection rate and a low aeration rate, and there was no comparative example in which both the BFE collection rate and the aeration rate were high.

10 Virus removal filter 11 1st base material 21 2nd base material 31 Intermediate fiber layer 100 Mask 110 Mask half body 130 Ear hook part 130a Opening part 150 Curved shape part

Claims (4)

A first base material made of an open cell foam sheet, an intermediate fiber layer made of nanofibers formed on one side of the first base material, and a second base material made of an open cell foam sheet laminated on the intermediate fiber layer. A virus removal filter composed of a base material. The virus removing filter according to claim 1, wherein the open cell foam sheet of the first base material and the second base material is made of a defilmed soft slab polyurethane foam sheet. The virus removing filter according to claim 1 or 2, wherein the nanofibers are polyurethane. The virus removal according to any one of claims 1 to 3, wherein the two mask semifields having an opening as an ear hook on one end side and a curved shape portion bulging outward on the other end side. A mask composed of a filter for use, in which the two mask halves are joined at the curved shape portion.

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