JP2022179160A - Manufacturing method of mask and sheet-like member for mask - Google Patents

Abstract

To provide a technique for suppressing damage of a filter layer and an increase of ventilation resistance when a shape retaining function is provided in a mask.SOLUTION: A mask according to one aspect of the present invention includes a mask body having a mouth layer which can cover the mouth of a wearer, an outer layer which is exposed to a non-skin side and is laminated on the mouth layer, and an intermediate sheet laminated between the mouth layer and the outer layer. The intermediate sheet has bending rigidity of a prescribed value or more, and the intermediate sheet includes a plurality of openings and fibers which have prescribed fiber diameters or less, which overlap with the plurality of openings.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present disclosure relates to a method for manufacturing a mask and a sheet-like member for a mask.

In recent years, there has been known a disposable mask in which ear straps or the like are attached to a mask body in which sheet members such as nonwoven fabric are laminated. Such a mask forms a three-dimensional shape that can cover the nose and mouth when worn by the wearer. Techniques for maintaining such a three-dimensional shape have also been disclosed (see Patent Documents 1 to 4, for example). Also, as a method for producing a nonwoven fabric, a method is disclosed in which a thermoplastic resin is melt-spun, made into a fiber stream by a high-speed gas, and then collected in a sheet form (for example, Patent Document 5).

Japanese Unexamined Patent Application Publication No. 2007-21027 Utility Model Registration No. 3220304 Utility Model Registration No. 3163625 Japanese Unexamined Patent Application Publication No. 2014-33973 JP-A-07-145542

In order to maintain the three-dimensional shape of the mask, it is conceivable to separately laminate a sheet-like member having higher bending rigidity than the nonwoven fabric on the filter layer of the mask body. However, in the case of such a mask, the filter layer may be perforated by the sheet-like member having high bending rigidity coming into contact with the filter layer during manufacture, transportation, or use. Therefore, the function of the filter layer may deteriorate. In particular, when the mask body is folded into a pleated shape, the folds of the sheet-like member with high bending rigidity are likely to harden, and the filter layer may be easily damaged.

Further, when the filter layer and the sheet-like member with high bending rigidity are laminated separately, the length (thickness) of the ventilation path is increased, and as a result, it is conceivable that the ventilation resistance is increased. Therefore, it is conceivable that a burden is applied when the wearer breathes.

In one aspect, the present disclosure has been made in view of such circumstances, and its purpose is to suppress damage to the filter layer and prevent an increase in airflow resistance when providing a mask with a shape maintaining function. It is to provide the technology to suppress.

In order to solve the above problems, in the present invention, the mask body is provided with a sheet-like member having both a filter function and a shape maintaining function.

Specifically, the mask according to one aspect of the present invention includes a mouth layer capable of covering the wearer's mouth, an outer layer exposed on the non-skin surface side and laminated on the mouth layer, the mouth layer and the outer layer. and an intermediate sheet laminated between layers, the intermediate sheet having a bending rigidity equal to or greater than a predetermined value, the intermediate sheet having a plurality of openings and a plurality of the openings and fibers having a predetermined fiber diameter or less that overlap with each other.

Moreover, in the mask according to the above aspect, the mask body may further have folds that can be expanded in a direction from the nose to the mouth when worn by the wearer.

Further, in the mask according to the above aspect, the average bending rigidity of the intermediate sheet may be in the range of 0.1 gf·cm ² to 0.5 gf·cm ² .

Further, in the mask according to the above aspect, the intermediate sheet has an aperture ratio in the range of 25% to 70%, and the total opening area of the plurality of apertures is 0.15 mm ² to 1.3 mm ² . , the basis weight of the fibers may be in the range of 10 g/m ² to 30 g/m ² , and the average fiber diameter of the fibers may be 5 μm or less.

Moreover, in the mask according to the above aspect, the intermediate sheet and the fibers may contain the same substance.

Further, in the mask according to the one aspect described above, the edge of the opening may be inclined with respect to the thickness direction of the intermediate sheet.

Further, in the mask according to the above aspect, the opening has a rectangular shape, the ratio of the long side to the short side of the opening is 1:1 to 5:1, and the length of the short side is 5 mm or less. may be

Further, a method for manufacturing a sheet-like member for a mask according to one aspect of the present invention includes a discharging step of discharging a thermoplastic resin from the tip of a nozzle; A fiberization step in which the thermoplastic resin is fiberized by jetting gas of a predetermined temperature from the oblique rear side of the nozzle at a predetermined pressure, and the fibers fiberized in the fiberization step are worn. An intermediate sheet having a plurality of openings, which is laminated between a mouth layer capable of covering the mouth of a person and an outer layer exposed on a non-skin surface side and laminated on the mouth layer, overlapping at least the openings of the intermediate sheet. and a cooling step in which the fibers overlapping at least the openings in the overlapping step are cooled.

ADVANTAGE OF THE INVENTION According to this invention, when providing a shape maintenance function to a mask, it can suppress that a filter layer is damaged and the increase in ventilation resistance can be suppressed.

FIG. 1 is an external perspective view of a mask according to an embodiment. FIG. 2 is a diagram showing the sheet structure of the mask according to the embodiment. FIG. 3 illustrates an outline of a manufacturing apparatus for manufacturing shape-retaining sheets. FIG. 4 is an example of a flowchart of steps for manufacturing a shape-retaining sheet. FIG. 5 illustrates an overview of the deposition of olefinic fibers on an olefinic film. FIG. 6 shows an example of the performance of shape-retaining sheets.

<Embodiment>
A mask and a mask manufacturing method according to an embodiment of the present invention will be described below with reference to the drawings. The configurations of the following embodiments are examples, and the present invention is not limited to the configurations of these embodiments.

FIG. 1 is an external perspective view of a mask according to an embodiment. As shown in FIG. 1, the mask 1 has a mask body 2, ear straps 3 and 4, side portions 5 and 6, and a nose fitter 7. As shown in FIG. The mask main body 2 is formed of a sheet-like breathable material and has a size capable of covering the wearer's mouth and nose. The ear straps 3 and 4 are formed of a string-like stretchable material, and are attached to the left and right sides of the mask body 2 by joining the ends at the side portions 5 and 6 located on both sides of the mask body 2 . Each forms an annular ring.

The mask body 2 is composed of various sheets such as nonwoven fabric having air permeability, and is a laminate of a plurality of sheets. The plurality of sheets are appropriately joined together at their upper, lower, left, and right edges. The mask body 2 has folds that can form a pleated three-dimensional shape. Such creases are held by the side portions 5 and 6 by joining the side portions 5 and 6 to the left and right end portions of the mask main body 2 folded in a pleat shape. That is, unfolding of the folds is prevented at the side portions 5 and 6 of the left and right ends, and the creases are unfolded in the region near the center of the mask body 2 when the mask 1 is worn, so that the pleats of the mask body 2 are formed. is expanded and becomes a three-dimensional shape. By closing the pleats when the mask is not worn, the mask body 2 can be flat and not bulky.

The string-like stretchable material constituting the ear straps 3 and 4 is formed of, for example, a mixed woven belt of rubber thread and cotton, a mixed knitted net of resin filaments, or a stretchable nonwoven fabric. Both ends of such a string-like material are joined to the left and right sides 5 and 6 of the mask body 2, respectively, so that one end of the material becomes a starting point and the other end of the material becomes a loop. Shaped ear straps 3 and 4 are formed on both left and right sides of the mask body 2 .

The nose fitter 7 is a member fixed to the mask body 2 in the upper part of the mask body 2 with its longitudinal direction extending in the lateral direction of the mask body 2 . The nose fitter 7 may be fixed inside the laminate in a state of being sandwiched between the sheet-like breathable materials that constitute the mask body 2, or may be fixed to the surface of the mask body 2. good too. The nose fitter 7 is made of a plastically deformable material that has enough strength to be deformed into an appropriate shape by being pressed by the wearer's fingers, and that maintains its shape even when the pressure is released. By providing such a nose fitter 7 on the upper part of the mask body 2 , the wearer can close the gap between the nose and the mask body 2 .

The above-described materials constituting the mask 1 are preferably joined by ultrasonic welding, but for example, sewing with sewing thread or the like, adhesion with hot melt adhesive or the like, heat sealing, or other various joining techniques can be applied. .

FIG. 2 is a diagram showing the sheet structure of the mask according to the embodiment. The mask body 2 according to the embodiment includes an outer layer sheet 10 (an example of the "outer layer" of the present disclosure), a shape-retaining sheet 12 (an example of the "intermediate sheet" of the present disclosure), and a skin sheet 13 (an example of the "mouth area" of the present disclosure). An example of "layer") is laminated. A nonwoven fabric is used for the outer layer sheet 10 and the skin sheet 13 . Also, the shape-retaining sheet 12 is a highly rigid sheet in which a plastic film and fibers are integrally molded (details will be described later).

Since the skin sheet 13 is in direct contact with the skin, a non-woven fabric that is particularly comfortable to the touch may be used. The outer layer sheet 10 may be a sheet made of the same material as the skin surface sheet 13, or may be a sheet of a different standard having excellent resistance to the external environment and breathability. In order to prevent erroneous attachment, the outer layer sheet 10 and the skin sheet 13 may have different colors.

Moreover, the mask body 2 is provided with pleated folds formed by folding back a laminate in which the outer layer sheet 10, the shape maintaining sheet 12, and the skin sheet 13 are laminated. In this embodiment, the crease extends in the left-right direction of the mask body 2 (hereinafter referred to as the "lateral direction") in plan view. Then, when the mask 1 is worn by the wearer and the folds are unfolded in the vertical direction of the mask body 2 in plan view (hereinafter referred to as the "vertical direction"), the pleats of the mask body 2 are widened to form a three-dimensional shape. Become. At this time, the side portions 5 and 6 of the mask body 2 prevent the folds from unfolding, so that a dome-shaped bulging portion is formed on the non-skin surface side of the wearer. Thereby, a space is formed between the mask main body 2 and the wearer's mouth, and the wearer can breathe easily.

However, as described above, the nonwoven fabric used for the outer layer sheet 10 and the skin sheet 13 of the mask body 2 is flexible. Therefore, even when the mask 1 is worn by the wearer and the three-dimensional shape is formed so as to cover the nose and mouth, when the wearer receives force due to the wearer's movement such as moving the mouth. Pleats tend to fold back and it is difficult to maintain the three-dimensional shape. Therefore, in the present embodiment, the three-dimensional shape of the mask body 2 is maintained by forming the shape maintaining sheet 12 using a plastic film with high bending rigidity.

FIG. 3 illustrates an outline of a manufacturing apparatus 50 that manufactures the shape-retaining sheet 12. As shown in FIG. As shown in FIG. 3, the manufacturing apparatus 50 includes a nozzle 51 and a nozzle die 52 on which the nozzle 51 is provided. The nozzle die 52 has an isosceles triangle in cross section, and the apex angle α is, for example, 80 degrees or more and 100 degrees or less. A row of nozzles 51 is drilled at the vertex end of the isosceles triangle. Although the shape of the nozzle 51 is not limited to the example shown in FIG. 3, the nozzle 51 is designed so that the vicinity of the apical end of the nozzle 51 does not substantially have a flat portion.

In addition, the manufacturing apparatus 50 is provided with a lip 53 with a certain gap 54 (for example, 1.0 mm or more and 2.0 mm or less, hereinafter also referred to as a lip gap) from both side surfaces in the width direction of the nozzle die 52 in FIG. . Further, the apical end of the nozzle 51 is arranged in a state of protruding downward from the lip 53 by a distance of 0 mm or more and 0.8 mm or less, for example.

FIG. 4 is an example of a flowchart of steps for manufacturing the shape-retaining sheet 12 using the manufacturing apparatus 50 shown in FIG.

(Step S1)
In step S1, an olefin film 8, which is an example of a plastic film, is arranged so as to face the apical end of the nozzle 51 (see FIG. 3). Here, the olefin film 8 is regularly provided with a plurality of holes throughout. A melted olefin resin (an example of a “thermoplastic resin” in the present disclosure) is discharged toward the olefin film 8 from the apex end of the nozzle 51 . The melt viscosity of the olefin resin passing through the nozzle 51 is, for example, 20 poise or more and 250 poise or less. Also, step S1 is an example of the "discharging step" of the present disclosure.

(Step S2)
In step S<b>2 , high-temperature, high-speed gas passes through the gap 54 and is jetted toward the olefin resin discharged from the vertex end of the nozzle 51 . Incidentally, the temperature of the gas is, for example, about 290.degree. Also, the injection pressure of the gas is, for example, 0.2 kg/cm ² or more and 1.0 kg/cm ² or less. By injecting the gas in this way, the olefin resin is thinned and further fibrillated into olefin fibers. Note that step S2 is an example of the "fiberization step" of the present disclosure.

(Step S3)
In step S3, the olefin fibers produced in step S2 are deposited on the olefin film 8. FIG.

FIGS. 5(A) and 5(B) illustrate an overview of the deposition of olefin fibers 55 on the olefin film 8. FIG. As shown in FIG. 5(A), the olefin film 8 is provided with holes 81 . The hole 81 has a rectangular shape with an aspect ratio of 1:1 to 5:1. Moreover, the short side of the hole 81 is 5 mm or less. In the example shown in FIG. 5, since an example of a partial enlarged view of the olefin film 8 is shown, description of the regular arrangement of the holes 81 is omitted.

Gas injected through the gap 54 passes through the holes 81 . That is, an air flow is formed between the nozzle 51 and the olefin film 8, and the fiberized olefin fibers 55 move according to the air flow. Then, the olefin fibers 55 that have moved are collected by the holes 81 .

Here, the edge 82 of the hole 81 is inclined with respect to the thickness direction of the film. That is, the thickness of the olefin film 8 gradually decreases as the hole 81 is approached. Olefin fibers 55 are deposited on the edge 82 of such an olefin film 8 . The holes 81 are then closed with the olefin fibers 55 . Note that step S3 is an example of the "overlapping step" of the present disclosure.

FIG. 5B is another example showing how the olefin fibers 55 are deposited. In FIG. 5A, the olefin fibers 55 are deposited on the edges 82 of the holes 81, but in FIG. ing. The olefin fibers 55 are deposited on the olefin film 8 as in at least one of FIG. 5(A) and FIG. 5(B).

(Step S4)
In step S<b>4 , the olefin resin is stopped from being discharged from the apex end of the nozzle 51 . Then, in step S3, the olefin film 8 with the olefin fibers 55 deposited on the edge 82 is left for a predetermined period of time to be cooled. The olefin fibers 55 are then adhered to the edge 82 . In this manner, the shape-retaining sheet 12 in which the olefin fibers 55 and the olefin film 8 are integrally formed is manufactured. Note that step S4 is an example of the “cooling step” of the present disclosure.

The manufacturing apparatus 50 may be adjusted so that the olefin fibers 55 are deposited not only on the edges 82 of the holes 81 but also on other areas of the olefin film 8 .

<Performance of Shape Retaining Sheet 12>
FIG. 6 shows an example of the performance of the shape-retaining sheet 12 manufactured using the manufacturing apparatus 50 as described above. The performance of the shape-retaining sheet 12 shown in FIG. 6 is exemplified by the performance of the shape-retaining sheet 12 manufactured by changing the specification of the olefin film 8 and the specification of the manufacturing apparatus 50 to various values.

More specifically, as shown in FIG. 6 , the shape-retaining sheets 12 of samples 1 to 6 had an opening ratio of the holes 81 of 25% to 70% and a total opening area of the holes 81 of 0. 0.15 mm ² to 1.3 mm ² , and a sheet when the bending rigidity is changed in the range of 0.1 gf cm ² (an example of “bending rigidity equal to or greater than a predetermined value” in the present disclosure) to 0.5 gf cm ² be. Further, with regard to the specifications of the manufacturing apparatus 50, the protrusion distance of the apex end of the nozzle 51 from the lip 53 downward in FIG. This is a sheet when the apex angle α is changed in the range of 80 degrees or more and 100 degrees or less. In the shape-retaining sheets 12 of samples 1 to 6 manufactured under these conditions, the basis weight of the olefin fibers 55 is 10 g/m ² to 30 g/m ² , the average fiber diameter of the olefin fibers 55 is 5 μm or less, and the olefin fibers 55 The variation in fiber diameter (standard deviation/average) was 1 or less. Also, the MB (meltblown) uniformity was above average.

In addition, since the shape-maintaining sheets 12 of samples 1 to 6 have an opening ratio of the holes 81 of 25% to 70%, the opening ratio is too high in the step of manufacturing the shape-maintaining sheet 12 (step S3). This prevented the olefin fibers 55 from passing through the holes 81 and moving to the opposite side. Therefore, deterioration of the particle trapping function of the shape-retaining sheet 12 was suppressed. In addition, when the opening ratio is too low, a suitable air flow is not formed between the nozzle 51 and the olefin film 8, and the olefin fibers 55 are prevented from being collected in the holes 81. Therefore, the maximum pore diameter [μm] of the shape-retaining sheets 12 of samples 1 to 6 was about 8.5 to 13, and the particle trapping probability was a high value of 80% or more. In addition, since the ventilation resistance was about 0.6 kPa·s/m, the wearer can breathe without any problem. In addition, since the sensory evaluation of the hardness of the mask was good, the sense of discomfort when wearing the mask was reduced.

On the other hand, the shape-maintaining sheets 12 of samples 7 to 11 were manufactured using the manufacturing apparatus 50 under the same conditions as the shape-maintaining sheets 12 of samples 1 to 6 were manufactured. However, as specifications of the olefin film 8, for example, the opening ratio of the holes 81 is 70% or more (sample 8), or the opening area of the holes 81 is less than 0.15 mm ² (samples 9 to 11) or greater than 1.3 mm ² ( Samples 7-8), or the shape-retaining sheets 12 of Samples 1-6 were changed such that the flexural rigidity was higher than 0.5 gf·cm ² (Samples 7-10). As a result, in the shape-retaining sheets 12 of samples 7 to 11, the basis weight of the olefin fibers 55 was less than 10 g/m ² (samples 7 to 8), and the MB (melt blown) uniformity was poor (samples 7 to 11 ). Moreover, the maximum pore diameter [μm] of the shape-retaining sheet 12 increased, and the particle trapping probability was significantly lower than that of the shape-retaining sheets 12 of samples 1-6.

The shape-retaining sheets 12 of samples 12 and 13 were manufactured using the manufacturing apparatus 50 under the same conditions and the olefin film 8 under the same conditions as when the shape-retaining sheets 12 of samples 1-6 were manufactured. However, due to variations in the manufacturing process, the average fiber diameter of the olefin fibers 55 is greater than 5 μm (sample 12), or the variation in fiber diameter (standard deviation/average) of the olefin fibers 55 is greater than 1 (sample 13). MB (meltblown) uniformity was poor (Samples 12-13). Moreover, the maximum pore diameter [μm] of the shape-retaining sheet 12 increased, and the particle trapping probability was significantly lower than that of the shape-retaining sheets 12 of samples 1-6.

The shape-retaining sheets 12 of samples 14 to 18 used the same film as the olefin film 8 used when the shape-retaining sheets 12 of samples 1 to 6 were manufactured. However, as the specifications of the manufacturing apparatus 50, the apex angle α end of the nozzle 51 protrudes from the lip 53 downward in FIG. ) or wider than 2 mm (Sample 16), or the apex angle α of the nozzle die 52 was set to less than 80 degrees (Sample 17) or 100 degrees or more (Sample 18). As a result, the maximum pore diameter [μm] of the shape-retaining sheets of samples 14-18 increased, and the particle trapping probability was significantly lower than that of the shape-retaining sheets 12 of samples 1-6.

The measurement of each performance of the shape-retaining sheet 12 is performed, for example, as follows.

(Measurement of opening ratio and opening area of hole 81)
The aperture ratio and aperture area of the holes 81 are obtained by photographing the olefin film 8 using a digital microscope. Then, the photographed image is binarized to extract the outer shape of the hole 81 and the outer shape of the olefin film 8 . Then, the opening ratio and opening area are measured by using the extracted outer shape of the holes 81 and outer shape information of the olefin film 8 . More specifically, first, the olefin film 8 is photographed with a digital microscope (for example, VHX-7000 manufactured by Keyence Corporation) in transmission mode at a magnification of 50 times. Then, the photographed image is binarized using image analysis software (for example, ImageJ manufactured by NIH). Then, for the holes 81 appearing in the binarized image, the ParticleAnalysys function is used to measure the total area and area ratio of the openings, which are defined as the opening ratio (%) and the opening area (mm ² ).

(Measurement of flexural rigidity of olefin film 8)
The olefin film 8 was cut into a size of 20 cm square, and the bending stiffness was measured with a pure bending tester (for example, KES-FB2 manufactured by Kato Tech Co., Ltd.). Measurements were taken at 8 points each in the MD (Machine Direction) direction and the CD (Cross Direction) direction, and the average value was calculated.

(Measurement of Average and Variation of Fiber Diameter of Olefin Fiber 55)
After photographing the olefin fibers 55 fixed to the shape-retaining sheet 12 with an electron microscope at a magnification of 2000, the fiber diameter was measured at 100 points using measurement software, and the average value was calculated. More specifically, an electron microscope (for example, VHX-D510 manufactured by Keyence Corporation) is used to photograph the olefin fibers 55 fixed to the shape-retaining sheet 12 at a magnification of 2000 times, and the olefin fibers 55 appearing in the photographed photograph. Among them, 100 fibers (n=100) were arbitrarily selected, the diameter (width) of the selected fibers was measured, and the arithmetic mean value was obtained as the average fiber diameter. Also, the ratio of the standard deviation of the fiber diameters to the average fiber diameter was calculated as the variation of the fiber diameters.

(Maximum Pore Diameter of Aggregate of Olefin Fibers 55)
For example, the measurement was performed with a PMI perm porometer. More specifically, a perm porometer manufactured by PMI (model: CFP-1200AEX), for example, was used as a measuring device. In this measuring device, the shape-retaining sheet 12 is used as a sample, and the shape-retaining sheet 12 is immersed in an immersion liquid whose surface tension is known in advance, and all the pores of the aggregate of the olefin fibers 55 fixed to the shape-retaining sheet 12 are immersed. Pressure is applied to the shape-retaining sheet 12 while it is covered with a liquid film, and the pore diameter of the pores calculated from the pressure at which the liquid film of the immersion liquid is broken and the surface tension of the immersion liquid is measured. For example, Silwick manufactured by PMI is used as the immersion liquid. , r (unit: N/m) is the surface tension of the immersion liquid, P (unit: Pa) is the pressure at which the liquid film of that pore size breaks, and C is the wetting tension of the immersion liquid. , is a constant determined by the contact angle and the like. } was used to determine the pore size. Further, the flow rate (wet flow rate, unit: L/min) was measured when the pressure P applied to the shape-retaining sheet 12 immersed in the immersion liquid was continuously changed from low pressure to high pressure. At the initial pressure, the flow rate is 0 L/min because even the largest pore liquid film is not broken. As the pressure is increased, the liquid film in the largest pores breaks and a flow occurs (bubble point). The pore diameter (μm) obtained by substituting the pressure at this bubble point into the above formula was defined as the maximum pore diameter.

(Particle Capture Rate of Shape Retaining Sheet 12)
For example, it is measured by TSI AFT8130A. More specifically, the shape-retaining sheet 12 was cut into 15 cm squares, and the collection efficiency was measured using, for example, a TSI filtration performance measuring instrument (AFT8130 manufactured by TSI). As a measurement condition, a 2.0% NaCl aqueous solution was supplied to an aerosol generator (
For example, an aerosol having an average particle size of 0.075 μm was passed through a model 8118) fixed to a holder having a diameter of 100 mmφ. The air flow rate was 92.4 L/min, the sampling time was 4 seconds, and the particles were not neutralized. The capture probability is calculated by measuring the NaCl concentration with a photometer before and after the sample.

(Airflow resistance of shape-maintaining sheet 12)
For example, it is measured by Kato Tech KESFB8. More specifically, the shape-retaining sheet 12 is cut into 10 cm squares, and, for example, using a KES-F8-AP1 ventilation resistance tester manufactured by Kato Tech Co., Ltd., the ventilation resistance ( kPa·s/m) was measured. Moreover, 5-point measurement was performed and the average value was calculated.

[Action/effect]
According to the mask 1 as described above, the olefin film 8 having high bending rigidity and the aggregate of the olefin fibers 55 having a filter function are integrated to form the shape maintaining sheet 12 . Therefore, it is possible to prevent the olefin film 8 from contacting the olefin fibers 55 while the mask 1 is being manufactured, transported, or used, thereby preventing holes in the assembly of the olefin fibers 55 . Therefore, deterioration of the filter function is suppressed.

Moreover, according to the mask 1 as described above, the olefin film 8 and the assembly of the olefin fibers 55 are integrally molded. Therefore, an increase in thickness is suppressed. Therefore, an increase in ventilation resistance is suppressed (see samples 1 to 6 in FIG. 6).

Further, according to the mask 1 as described above, the shape-retaining sheet 12 includes the olefin film 8 having high rigidity. Therefore, the flexural rigidity of the mask body 2 is improved as compared with the case where the mask body 2 is made of ordinary non-woven fabric. Therefore, in the mask 1 that is worn by the wearer and forms a three-dimensional shape along the skin of the face, the shape-retaining sheet 12 can resist the force of the pleats tending to shrink in the vertical direction. Therefore, deformation of the three-dimensional shape of the mask body 2 with the unfolded pleats can be suppressed. Therefore, the formation of a gap between the mask main body 2 and the wearer's skin is suppressed. Therefore, deterioration of the particle trapping function of the mask 1 is suppressed.

Further, according to the mask 1 as described above, the olefin film 8 and the olefin fibers 55 forming the shape-retaining sheet 12 contain olefin molecules, which are the same substance. Therefore, the adhesion between the olefin film 8 and the olefin fibers 55 is improved. Therefore, it is suppressed that the particle trapping function of the shape-retaining sheet 12 deteriorates due to the separation of the olefin fibers 55 from the olefin film 8 .

Further, according to the mask 1 as described above, the edges 82 of the holes 81 are inclined with respect to the thickness direction of the olefin film 8 as shown in FIG. Therefore, the edge 82 has an increased contact area with the olefin fibers 55 .
Therefore, the bonding strength of the olefin fibers 55 to the edge 82 is increased. Therefore, peeling of the olefin fibers 55 from the edge 82 is suppressed. Therefore, deterioration of the particle capturing function of the shape-retaining sheet 12 is suppressed.

Further, according to the mask 1 as described above, the holes 81 provided in the shape-maintaining sheet 12 have a rectangular shape with an aspect ratio of 1:1 to 5:1 and a short side of 5 mm or less. Therefore, in the step of manufacturing the shape-retaining sheet 12 (step S3), the olefin fibers 55 are prevented from passing through the holes 81 and moving to the opposite side. Therefore, deterioration of the particle capturing function of the shape-retaining sheet 12 is suppressed.

<Modification>
The mask body 2 may not have creases that can form a pleated three-dimensional shape. Further, as an alternative to the olefin film 8, a highly rigid sheet-like member made of a material different from olefin may be provided. Fibers having molecules different from olefin may also be fixed on the olefin film 8 . Also, the shape of the edge 82 of the hole 81 does not have to be slanted as described above. Also, the shape and size of the hole 81 are not limited to the examples of the above embodiments.

The embodiments and modifications disclosed above can be combined.

1: mask 2: mask body 3: ear strap 4: ear strap 5: side part 6: side part 7: nose fitter 8: olefin film 10: outer layer sheet 12: shape maintaining sheet 13: skin sheet 50: manufacturing device 51 : Nozzle 52 : Nozzle die 53 : Lip 54 : Gap 55 : Olefin fiber 81 : Hole 82 : Edge

Claims (8)

It has a mouth layer capable of covering the wearer's mouth, an outer layer exposed on the non-skin side and laminated on the mouth layer, and an intermediate sheet laminated between the mouth layer and the outer layer. Equipped with a mask body,
The intermediate sheet has a bending rigidity equal to or greater than a predetermined value,
The intermediate sheet has a plurality of openings and fibers having a predetermined fiber diameter or less overlapping the plurality of openings.
mask. The mask body further has folds that can be deployed in a direction from the nose to the mouth when worn by the wearer,
A mask according to claim 1. The average bending stiffness of the intermediate sheet is in the range of 0.1 gf cm ² to 0.5 gf cm ² ,
A mask according to claim 1 or 2. The aperture ratio of the intermediate sheet is in the range of 25% to 70%,
The sum of the opening areas of the plurality of openings is within the range of 0.15 mm ² to 1.3 mm ² ,
The fiber basis weight is in the range of 10 g/m ² to 30 g/m ² ,
The average fiber diameter of the fibers is 5 μm or less,
A mask according to any one of claims 1 to 3. said intermediate sheet and said fibers comprise the same material;
Mask according to any one of claims 1 to 4. the edge of the opening is inclined with respect to the thickness direction of the intermediate sheet;
6. A mask according to any one of claims 1-5. The opening has a rectangular shape,
The ratio of the long side to the short side of the opening is 1:1 to 5:1,
The length of the short side is 5 mm or less,
7. A mask according to any one of claims 1-6. a discharge step in which the thermoplastic resin is discharged from the tip of the nozzle;
A fiberization step in which gas of a predetermined temperature is jetted at a predetermined pressure to the thermoplastic resin discharged from the tip of the nozzle from an obliquely rearward direction when viewed from the tip of the nozzle, thereby fiberizing the thermoplastic resin. When,
The fibers fiberized in the fiberizing step are laminated between a mouth layer capable of covering the wearer's mouth and an outer layer exposed on the non-skin surface side and laminated on the mouth layer, and a plurality of an overlapping step of overlapping at least the opening of an intermediate sheet having an opening;
a cooling step in which the fibers overlapping at least the openings in the overlapping step are cooled;
A method for manufacturing a mask sheet member.

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