Nonwoven mask and its manufacturing method

Abstract

To provide a nonwoven mask which is easily manufactured while making it difficult for a wearer to feel stuffiness by keeping a mask body in an outwardly swollen state when worn.SOLUTION: In a nonwoven mask, a mask body 10 is configured by overlapping an outside nonwoven fabric 11 forming an outer face of the mask body 10, an inside nonwoven fabric 12 forming an inner face of the mask body 10, and a filter sheet 13 arranged in a gap space between the outside nonwoven fabric 11 and the inside nonwoven fabric 12. A shape retention sheet 14 which spreads in a vertical direction and a longitudinal direction is arranged in the gap space in a state of being overlapped with a planer region α1 which substantially crosses a middle section of the mask body 10 in the longitudinal direction.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a nonwoven mask and a method for manufacturing the same. [Background technology]

[0002] With the spread of the novel coronavirus disease (COVID-19), more and more people are wearing masks on a daily basis. While various types of masks are available on the market, including those made from nonwoven fabric (nonwoven masks), cloth (cloth masks), and urethane foam (urethane masks), recent research has shown that nonwoven masks offer better protection against droplets than cloth or urethane masks, and so wearing nonwoven masks is recommended. However, nonwoven masks have the drawback of being poorly breathable, making them difficult for the wearer to breathe.

[0003] To eliminate the breathlessness of nonwoven fabric masks, nonwoven fabric masks have been introduced that have shape-retaining wires 16 embedded in the vertically central portion of the mask body 10 so as to extend in the left-right direction, as shown in Fig. 1 (see, for example, "linear shape-retaining wires 9" in Figs. 1 and 2 of Patent Document 1). This shape-retaining wire 16 keeps the mask body 10 in a state where it expands outward when the nonwoven fabric mask is worn, ensuring space between the mask body 10 and the mouth. This reduces the breathlessness felt by the wearer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Publication No. 3230190 Summary of the Invention [Problem to be solved by the invention]

[0005] However, as shown in FIG. 1, nonwoven masks in which the shape-retaining wire 16 is arranged laterally in the vertical middle of the mask body 10 have the drawback of being time-consuming to manufacture. In this type of nonwoven mask, the shape-retaining wire 16 is accommodated in the gap between the nonwoven fabric (outer nonwoven fabric) that forms the outer surface of the mask body 10 and the nonwoven fabric (inner nonwoven fabric) that forms the inner surface of the mask body 10. Therefore, it is necessary to secure the shape-retaining wire 16 to the outer and inner nonwoven fabrics at locations above and below the shape-retaining wire 16 to prevent the shape-retaining wire 16 from moving vertically. In the nonwoven mask shown in FIG. 1, the outer and inner nonwoven fabrics that form the mask body 10 are welded along a pair of upper and lower welding lines L6 and L7, and the shape-retaining wire 16 is inserted into the gap between the outer and inner nonwoven fabrics, between the welding lines L6 and L7.

[0006] The present invention has been made to solve the above problems, and aims to provide a nonwoven fabric mask that is easy to manufacture while keeping the mask body inflated outward when worn, making it less likely for the wearer to feel short of breath. Another object of the present invention is to provide a method for manufacturing this nonwoven fabric mask. [Means for solving the problem]

[0007] The above issues are: The mask body is An outer nonwoven fabric that forms the outer surface of the mask body; An inner nonwoven fabric that forms the inner surface of the mask body; A filter sheet disposed in the gap space between the outer nonwoven fabric and the inner nonwoven fabric; A nonwoven mask constructed by layering A shape-retaining sheet extending in the vertical and horizontal directions is arranged in the gap space so as to overlap a planar region that substantially crosses the middle portion of the mask body in the horizontal direction. A nonwoven mask characterized by This is solved by providing

[0008] Here, the term "shape-retaining sheet" refers to a thin, planar material that has shape-retaining properties. A material that has better shape-retaining properties (a material with higher bending resistance) than the other planar materials that make up the mask body, such as the outer nonwoven fabric and the inner nonwoven fabric, is selected as the shape-retaining sheet. Because this shape-retaining sheet constitutes the mask body, it is typically made of a breathable material (woven fabric, nonwoven fabric, etc.). In particular, a resin-fused nonwoven fabric in which short fibers made of a thermoplastic resin are fused together has breathability while also having a higher bending resistance than other nonwoven fabrics of a similar thickness, and therefore can be suitably used as the shape-retaining sheet.

[0009] The shape-retaining sheet may be made of the same material as the filter sheet (the filter sheet may function as the shape-retaining sheet, or the shape-retaining sheet may function as the filter sheet). In this case, the mask body can be made of three layers: [1] outer nonwoven fabric, [2] inner nonwoven fabric, and [3] filter sheet / shape-retaining sheet. However, the filter sheet is required to have different performance than the shape-retaining sheet (blocking performance against foreign substances such as viruses and bacteria). For this reason, the shape-retaining sheet is usually made separate from the filter sheet. In this case, the mask body is made of four or more layers: [1] outer nonwoven fabric, [2] inner nonwoven fabric, [3] filter sheet, and [4] shape-retaining sheet.

[0010] In the nonwoven fabric mask of the present invention, the component for maintaining the mask body in an outwardly expanded state when worn is a shape-retaining sheet that extends in the vertical and horizontal directions. This creates significant friction between the component (shape-retaining sheet) and the outer nonwoven fabric, inner nonwoven fabric, and filter sheet. Therefore, even if the outer nonwoven fabric and inner nonwoven fabric are not fastened (e.g., welded) along the upper and lower edges of the shape-retaining sheet, the component (shape-retaining sheet) is less likely to shift vertically. This reduces the process of fastening the outer nonwoven fabric and inner nonwoven fabric. Additionally, when overlapping the outer nonwoven fabric, inner nonwoven fabric, and filter sheet, the shape-retaining sheet can also be overlapped. This eliminates the need to insert a shape-retaining sheet into the gap between the outer nonwoven fabric and inner nonwoven fabric. This allows for easy production of a nonwoven fabric mask that maintains the mask body in an outwardly expanded state when worn.

[0011] In the nonwoven fabric mask of the present invention, the mask body preferably has a plurality of pleats extending in the left-right direction, and a shape-retaining sheet is preferably disposed so as to overlap at least one of the plurality of pleats. This allows the mask body to easily bulge outward when worn. In addition, the pleats are processed by creating creases in the mask body (forming mountain folds and valley folds). At these creases, not only the outer nonwoven fabric and inner nonwoven fabric, but also the shape-retaining sheet are folded, further reducing the vertical displacement of the shape-retaining sheet.

[0012] In a typical nonwoven mask, the outer and inner nonwoven fabrics are welded (bonded) together at least along their left and right edges to prevent the mask body from coming apart. In this regard, in the nonwoven mask of the present invention, it is preferable to weld the left and right edges of the shape-retaining sheet together with the left and right edges of the outer and inner nonwoven fabrics. This fixes the shape-retaining sheet to the outer and inner nonwoven fabrics, making it less likely for the shape-retaining sheet to shift position in the vertical direction.

[0013] In the nonwoven fabric mask of the present invention, the shape-retaining sheet may be placed inside the filter sheet (in the gap between the filter sheet and the inner nonwoven fabric). However, because the shape-retaining sheet has stiffness, if it is placed near the inner nonwoven fabric, its stiff texture will be easily transmitted to the wearer's mouth through the inner nonwoven fabric, which may make the nonwoven fabric mask uncomfortable to wear. For this reason, it is preferable to place the shape-retaining sheet as close to the outer nonwoven fabric as possible in the gap space between the outer nonwoven fabric and the inner nonwoven fabric (between the outer nonwoven fabric and the filter sheet). This makes it possible to improve the comfort of the nonwoven fabric mask. [Effects of the Invention]

[0014] As described above, the present invention makes it possible to provide a nonwoven fabric mask that is easy to manufacture while keeping the mask body inflated outward when worn, making it less likely for the wearer to feel short of breath. It also makes it possible to provide a method for manufacturing this nonwoven fabric mask. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a front view showing a conventional nonwoven fabric mask. [Figure 2] FIG. 1 is a perspective view showing a nonwoven fabric mask according to the present invention. [Figure 3] FIG. 1 is a front view showing a nonwoven fabric mask according to the present invention. [Figure 4] 1 is a cutaway perspective view showing a nonwoven fabric mask according to the present invention, broken at the left-right middle portion of the mask body. FIG. [Figure 5] 1 is a cross-sectional view showing a state in which the mask body of the nonwoven fabric mask according to the present invention is cut along a plane perpendicular to the left-right direction. FIG. [Figure 6] 1 is a side view showing a nonwoven fabric mask manufacturing apparatus according to the present invention. [Figure 7] 1 is an enlarged perspective view showing the periphery of a guide member in a nonwoven fabric mask manufacturing apparatus according to the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0016] A preferred embodiment of the nonwoven fabric mask of the present invention will be described in more detail with reference to the drawings. The configuration described below is merely an example, and the technical scope of the present invention is not limited to the configuration described below. The nonwoven fabric mask of the present invention can be appropriately modified within the scope that does not impair the spirit of the invention.

[0017] 1. Overview of the nonwoven fabric mask according to the present invention Fig. 2 is a perspective view showing a nonwoven fabric mask according to the present invention. Fig. 3 is a front view showing a nonwoven fabric mask according to the present invention. As shown in Figs. 2 and 3, the nonwoven fabric mask of this embodiment is composed of a mask body 10 and ear loops 20.

[0018] The mask body 10 is a component that covers the area around the mouth of the wearer of the nonwoven fabric mask. This mask body 10 prevents foreign substances in the air (such as viruses, bacteria, pollen, and dust) from entering the wearer's mouth and nose, and prevents droplets from the wearer's mouth from scattering to the surrounding area. The lateral width W1 (FIG. 3) of the mask body 10 is set to a range of approximately 150 to 180 mm if the nonwoven fabric mask is for adults, and to a range of approximately 100 to 150 mm if the nonwoven fabric mask is for children. Furthermore, the vertical width W2 (FIG. 3) of the mask body 10 is set to a range of approximately 80 to 120 mm (if the mask body 10 has pleats P, as in the nonwoven fabric mask of this embodiment, this is the value when the pleats P are formed; the same applies below) regardless of whether the nonwoven fabric mask is for adults or children.

[0019] On the other hand, the ear loops 20 are components for hanging over the ears of the nonwoven mask. A pair of ear loops 20 are provided on the left and right sides of the mask body 10. When this pair of ear loops 20 is hung over the left and right ears, respectively, the mask body 10 is positioned around the wearer's mouth. In the nonwoven mask of this embodiment, the ear loops 20 are provided by fastening (by welding, etc.) string material made of a separate material from the mask body 10 to the left and right edges of the mask body 10, but the ear loops 20 can also be provided in a manner that is continuous with the mask body 10 (by extending the mask body 10 in the left-right direction and forming holes for hanging the ears in the extended portions).

[0020] The nonwoven fabric mask of the present invention is not particularly limited in its use. The nonwoven fabric mask of the present invention can be suitably used as a household mask or sanitary mask worn for the purposes of virus protection, hay fever protection, and PM2.5 protection, as well as a dust mask to prevent dust from flying at work sites and a medical mask worn in medical settings. The nonwoven fabric mask of this embodiment is intended to be used as a household mask or sanitary mask.

[0021] 2. Mask body configuration Fig. 4 is a cutaway perspective view showing a nonwoven fabric mask according to the present invention cut at the left-right middle of the mask body 10. Fig. 5 is a cross-sectional view showing the mask body 10 of the nonwoven fabric mask according to the present invention cut along a plane perpendicular to the left-right direction. In the nonwoven fabric mask of this embodiment, as shown in Figs. 4 and 5, the mask body 10 is formed by overlapping an outer nonwoven fabric 11, an inner nonwoven fabric 12, a filter sheet 13, and a shape-retaining sheet 14. A longitudinal (linear or strip-shaped) folding member 15 is attached to a location along the upper edge of the mask body 10.

[0022] 2.1 Outer non-woven fabric and inner non-woven fabric Of the components constituting the mask body 10, the outer nonwoven fabric 11 is a sheet material that forms the outer surface of the mask body 10, and the inner nonwoven fabric 12 is a sheet material that forms the inner surface of the mask body 10. In order to reduce the breathlessness felt by the wearer of the nonwoven fabric mask, nonwoven fabrics with a certain degree of breathability are used for the outer nonwoven fabric 11 and the inner nonwoven fabric 12. Specifically, the breathability is 100 to 500 cm. 3 / cm 2 A nonwoven fabric having a viscosity of about 313 cm can be suitably used as the outer nonwoven fabric 11 and the inner nonwoven fabric 12. Here, "air permeability" refers to the air permeability measured in accordance with "Method A (Fragile method)" in "JIS L 1096" "Testing Methods for Woven and Knit Fabrics." In the nonwoven fabric mask of this embodiment, the air permeability of the outer nonwoven fabric 11 is 313 cm. 3 / cm 2 s degree, the inner nonwoven fabric 12 breathability is 319 cm 3 / cm 2 Of the outer nonwoven fabric 11 and the inner nonwoven fabric 12, the outer nonwoven fabric 11 is subjected to an antibacterial treatment. Similarly, the inner nonwoven fabric 12 can also be subjected to an antibacterial treatment.

[0023] 2.2 Filter Sheet The filter sheet 13 is a sheet material for blocking foreign substances (viruses, bacteria, pollen, dust, etc.). For this reason, a sheet material with a finer mesh and lower air permeability than the outer nonwoven fabric 11 and the inner nonwoven fabric 12 is selected for the filter sheet 13. The air permeability of the filter sheet 13 is generally 1 to 200 cm 3 / cm 2 In the nonwoven mask of this embodiment, the air permeability is set in the range of 45 cm 3 / cm 2 A meltblown nonwoven fabric of the type s is used as the filter sheet 13. The filter sheet 13 is accommodated in the gap space between the outer nonwoven fabric 11 and the inner nonwoven fabric 12.

[0024] 2.3 Shape-retaining sheet The shape-retaining sheet 14 is a thin sheet material that keeps the mask body 10 in an outwardly bulged state (a state in which an outwardly convex arch is formed from the left to right portion of the mask body 10) so that, when the nonwoven mask is worn, there is space between the area around the wearer's mouth and the inner surface of the mask body 10. For this reason, a sheet material with a higher stiffness than the other sheet materials that make up the mask body 10 (the outer nonwoven fabric 11, the inner nonwoven fabric 12, and the filter sheet 13) is selected for the shape-retaining sheet 14.

[0025] The shape-retaining sheet 14 typically has a bending resistance of 0.1 mN or greater. Here, "bending resistance" refers to the bending resistance measured in accordance with "Method A (Gurley method)" in "JIS L 1096, Testing Methods for Woven and Knit Fabrics." If the shape-retaining sheet 14 has anisotropy, this refers to the bending resistance in the left-right direction of the shape-retaining sheet 14. The shape-retaining sheet 14 preferably has a bending resistance of 0.15 mN, more preferably 0.2 mN or greater. However, if the shape-retaining sheet 14 has an excessively high bending resistance, the mask body 10 may not conform to the wearer's mouth, potentially resulting in a poor wearing comfort. Furthermore, the periphery of the mask body 10 may lift up from the wearer's face, potentially allowing foreign matter to enter or droplets to be dispersed. For this reason, the shape-retaining sheet 14 typically has a bending resistance of 5.0 mN or less. The bending resistance of the shape-retaining sheet 14 is preferably 2.0 mN or less, and more preferably 1.0 mN or less. The bending resistance of the shape-retaining sheet 14 can also be made even lower, such as 0.5 mN or less or 0.3 mN or less. In the nonwoven fabric mask of this embodiment, the bending resistance of the shape-retaining sheet 14 is approximately 0.22 mN.

[0026] This shape-retaining sheet 14 is not particularly required to have the ability to block foreign matter like the filter sheet 13. For this reason, in order to make it easier for the wearer of the nonwoven fabric mask to breathe, it is preferable that the air permeability of the shape-retaining sheet 14 be as high as possible within the range that ensures the shape retention of the shape-retaining sheet 14. The air permeability of the shape-retaining sheet 14 is 300 cm 3 / cm 2 s or more, and 500 cm 3 / cm2 s or more is more preferable, and 600 cm 3 / cm 2 It is more preferable that the air permeability of the shape-retaining sheet 14 is 1000 cm or more. Although there is no particular upper limit to the air permeability of the shape-retaining sheet 14, if the air permeability of the shape-retaining sheet 14 is made too high, it becomes difficult to ensure the bending resistance of the shape-retaining sheet 14. For this reason, the air permeability of the shape-retaining sheet 14 is usually set to 1000 cm or more. 3 / cm 2 The air permeability of the shape-retaining sheet 14 is 800 cm 3 / cm 2 s or less, and 700 cm 3 / cm 2 In the nonwoven fabric mask of this embodiment, the air permeability of the shape-retaining sheet 14 is 637 cm 3 / cm 2 It is about s.

[0027] Various sheet materials can be used for the shape-retaining sheet 14, but typically, woven fabric or nonwoven fabric is used. More preferably, nonwoven fabric is used. Examples of fibers constituting the woven fabric or nonwoven fabric used for the shape-retaining sheet 14 include chemical fibers such as polyethylene terephthalate, polyester, polyethylene, polypropylene, polyurethane, polyvinyl chloride, nylon, aramid, vinylon, vinylidene, acrylic, acetate, and rayon, and natural fibers such as cotton, linen, wool, and silk.

[0028] However, if the above-mentioned bending resistance is imparted to the nonwoven fabric, the nonwoven fabric becomes thicker, and the weight of the nonwoven fabric mask increases. For this reason, the thickness of the nonwoven fabric used as the shape-retaining sheet 14 should be kept to 1.0 mm or less. The thickness of the shape-retaining sheet 14 is preferably 0.4 mm or less, and more preferably 0.2 mm or less. However, if the nonwoven fabric used as the shape-retaining sheet 14 is too thin, the shape-retaining sheet 14 becomes more likely to tear. For this reason, the thickness of the shape-retaining sheet 14 is usually set to 0.05 mm or more. In the nonwoven fabric mask of this embodiment, the thickness of the shape-retaining sheet 14 is approximately 0.16 mm.

[0029] In this regard, a resin-fused nonwoven fabric in which short fibers made of a thermoplastic resin are fused can impart the necessary bending resistance even to a thin nonwoven fabric as described above. In the nonwoven fabric mask of this embodiment, a resin-fused nonwoven fabric in which short fibers made of polyethylene terephthalate are fused is used as the shape-retaining sheet 14.

[0030] This shape-retaining sheet 14 is arranged so as to overlap the planar region α1 (the portion indicated by hatching in the figures) shown in Figures 2 and 3. Planar region α1 is an area that roughly crosses the middle section of the mask body 10 (the middle section in the up-down direction) in the left-right direction, and the left-right width W4 (Figure 3) of the shape-retaining sheet 14 is usually approximately the same as the left-right width W1 of the mask body 10. This shape-retaining sheet 14 extends not only in the left-right direction but also in the up-down direction. Therefore, the planar region α1 on which the shape-retaining sheet 14 is arranged also has a predetermined width not only in the left-right direction but also in the up-down direction (up-down width W3 in Figure 3).

[0031] In this way, by using a shape-retaining sheet 14 that extends in the vertical and horizontal directions, it is possible to ensure a wide contact area between the shape-retaining sheet 14 and the outer nonwoven fabric 11, and between the shape-retaining sheet 14 and the filter sheet 12. This allows for large friction to be generated between the shape-retaining sheet 14 and the outer nonwoven fabric 11, and between the shape-retaining sheet 14 and the filter sheet 12. Therefore, even without welding the outer nonwoven fabric 11 and the inner nonwoven fabric 12 at locations along the upper and lower edges of the shape-retaining sheet 14 (planar region α1), the shape-retaining sheet 14 is less likely to shift position in the vertical direction. This makes it possible to reduce the number of steps required to bond the outer nonwoven fabric 11 and the inner nonwoven fabric 12 together.

[0032] Because the shape-retaining sheet 14 is a thin, planar material, if its vertical width W3 (FIG. 3) is too narrow, it may not be able to exhibit the required shape retention. Furthermore, it may be difficult to ensure the contact area between the shape-retaining sheet 14 and the outer nonwoven fabric 11, and the contact area between the shape-retaining sheet 14 and the filter sheet 12, which may reduce the friction. For this reason, the vertical width W3 of the shape-retaining sheet 14 (when the mask body 10 has pleats P, as in the nonwoven fabric mask of this embodiment, and the shape-retaining sheet 14 is also folded at the pleats P, this refers to the width after folding; the same applies below) is typically set to 10 mm or more. The vertical width W3 of the shape-retaining sheet 14 is preferably 20 mm or more, more preferably 30 mm or more, and even more preferably 40 mm or more.

[0033] However, if the vertical width W3 of the shape-retaining sheet 14 is made too wide (too close to the vertical width W2 of the mask body 10), the entire mask body 10 may become stiff, which may result in a poor wearing comfort of the nonwoven mask. For this reason, the vertical width W3 of the shape-retaining sheet 14 is typically set to 0.9 times or less the vertical width W2 of the mask body 10. The vertical width W3 of the shape-retaining sheet 14 is preferably set to 0.8 times or less the vertical width W2 of the mask body 10, more preferably 0.7 times or less, and even more preferably 0.6 times or less. More specifically, the vertical width W3 of the shape-retaining sheet 14 is typically set to 90 mm or less, preferably 80 mm or less, more preferably 70 mm or less, and even more preferably 60 mm or less. In the nonwoven mask of this embodiment, the vertical width W2 of the mask body 10 is approximately 95 mm, while the vertical width W3 of the shape-retaining sheet 14 is approximately 50 mm, and the ratio W3 / W2 of the vertical width W3 to the vertical width W2 is just over 0.5.

[0034] As already mentioned, the shape-retaining sheet 14 may be formed from a single member common to the filter sheet 13 (the filter sheet 13 may function as the shape-retaining sheet 14). However, the filter sheet 13 is required to have the ability to block foreign matter, whereas the shape-retaining sheet 14 is required to have shape-retaining properties. For this reason, it is not necessarily easy to form the filter sheet 13 and the shape-retaining sheet 14 from a common member. Therefore, in the nonwoven mask of this embodiment, the filter sheet 13 and the shape-retaining sheet 14 are formed from separate members.

[0035] The shape-retaining sheet 14, together with the filter sheet 14, is accommodated in the gap space between the outer nonwoven fabric 11 and the inner nonwoven fabric 12. There is no particular limitation as to which of the filter sheet 13 and the shape-retaining sheet 14 is arranged on the outer side (the outer nonwoven fabric 11 side) and which is arranged on the inner side (the inner nonwoven fabric 12 side). However, because the shape-retaining sheet 14 is made of a stiffer material than the filter sheet 13, it is preferable to arrange it in a location away from the wearer's mouth. In the nonwoven fabric mask of this embodiment, the shape-retaining sheet 14 is arranged on the outer side of the filter sheet 13. This makes it less likely that the stiff texture of the shape-retaining sheet 14 will reach the wearer's mouth, improving the comfort of wearing the nonwoven fabric mask.

[0036] 2.4 Bending members The folding member 15 is a longitudinal member that can be bent into a desired shape. By pinching and bending this folding member 15 with fingers or the like, the upper edge of the mask body 10 can be fitted around the wearer's nose. This folding member 15 is also called a "nose fit." Various materials that undergo plastic deformation without breaking when bent can be used for the folding member 15. While metal materials such as wire can also be used for the folding member 15, it is preferable to use a resin material for safety reasons. In the nonwoven fabric mask of this embodiment, a narrow strip made of shape-retaining polyethylene is used as the folding member 15.

[0037] The folding member 15 may be attached to the outer surface of the mask body 10, but is usually embedded in the mask body 10 (covered by the outer nonwoven fabric 11 and the inner nonwoven fabric 12). In the nonwoven fabric mask of this embodiment, as shown in Fig. 5, the upper edge of the inner nonwoven fabric 12 is folded back toward the outer surface of the mask body 10 to form a sheath-shaped portion 10a along the upper edge of the mask body 10, and the folding member 15 is inserted into the sheath-shaped portion 10a through a slit 10b (Fig. 4) formed in the inner nonwoven fabric 12. The sheath-shaped portion 10a has welding lines L1 and L2 that weld the outer nonwoven fabric 11 and the inner nonwoven fabric 12 together, and these welding lines L1 and L2 prevent the folding member 15 from shifting in the vertical direction.

[0038] 2.5 pleats In the nonwoven fabric mask of this embodiment, as shown in FIGS. 4 and 5, a total of four pleats P (pleats P1, P2, P3, P4) extending in the left-right direction are formed in the mask body 10. Each of the pleats P1, P2, P3, P4 is composed of two folds (a pair of mountain folds β1 and valley folds β2). This makes it easier for the mask body 10 to bulge outward when worn. In addition, the shape retention of the mask body 10 in the left-right direction can be improved. Therefore, it is easier to maintain a space around the wearer's mouth, making it less likely for the wearer of the nonwoven fabric mask to feel short of breath. The number of pleats P is not limited to four. The number of pleats P may be three or less, or five or more.

[0039] The shape-retaining sheet 14 and filter sheet 13 are housed inside the mask body 10 (the gap between the outer nonwoven fabric 11 and the inner nonwoven fabric 12), and the filter sheet 13 is also folded where it overlaps with the pleats P1, P2, P3, and P4. On the other hand, the shape-retaining sheet 14 is arranged only in the planar region α1 that roughly crosses the middle section of the mask body 10 in the left-right direction, and therefore the shape-retaining sheet 14 is folded only where it overlaps with the second pleat P2 and the third pleat P3 (it is not folded where it overlaps with the first pleat P1 and the fourth pleat P4).

[0040] In this way, the shape-retaining sheet 14 is arranged overlapping the pleats P2 and P3, and creases are made in the shape-retaining sheet 14 where it overlaps the pleats P2 and P3, allowing the shape-retaining sheet 14 to be caught at the creases. This reduces vertical displacement of the shape-retaining sheet 14. The pleats P1 to P4 may be formed in a so-called "wheel pleat" configuration, in which the creases face in the same direction. However, in the nonwoven mask of this embodiment, the creases of the lower two rows of pleats P1 and P2 and the creases of the upper two rows of pleats P3 and P4 face in opposite directions, in which case they are formed in a so-called "box pleat" configuration. This enhances the integrity of the shape-retaining sheet 14 and the other planar materials (the outer nonwoven fabric 11, the inner nonwoven fabric 12, and the filter sheet 13), further reducing vertical displacement of the shape-retaining sheet 14.

[0041] 2.6 Other In the nonwoven fabric mask of this embodiment, as described above, the mask body 10 is constructed by stacking four sheets of sheet material (outer nonwoven fabric 11, inner nonwoven fabric 12, filter sheet 13, and shape-retaining sheet 14). Therefore, these four sheets of sheet material must be secured together to prevent them from coming apart. In this regard, in the nonwoven fabric mask of this embodiment, as shown in FIG. 3 , the outer nonwoven fabric 11, inner nonwoven fabric 12, and filter sheet 13 are welded (secured) to each other by welding lines L1 and L2 along the upper edge of the mask body 10, welding line L3 along the lower edge of the mask body 10, welding line L4 along the left edge of the mask body 10, and welding line L5 along the right edge of the mask body 10. The shape-retaining sheet 14 is also welded along welding line L4 and welding line L5. This further reduces the likelihood of the shape-retaining sheet 14 shifting out of position.

[0042] 3. Manufacturing method of nonwoven masks Finally, a method for manufacturing the nonwoven fabric mask of this embodiment will be described. Fig. 6 is a side view showing a nonwoven fabric mask manufacturing apparatus. As shown in Figs. 4 and 5, the nonwoven fabric mask of this embodiment has a mask body 10 with a structure in which four sheets of sheet material (outer nonwoven fabric 11, inner nonwoven fabric 12, filter sheet 13, and shape-retaining sheet 14) are stacked on top of each other. As shown in Fig. 6, the sheet materials 11, 14, 13, and 12 unwound from four winding rolls 51, 52, 53, and 54 are passed through the gap between a pair of upper and lower overlapping rollers 70, so that these four sheets of sheet material are stacked on top of each other.

[0043] The first winding roll 51 unwinds the sheet material that will become the outer nonwoven fabric 11, the second winding roll 52 unwinds the sheet material that will become the shape-retaining sheet 14, the third winding roll 53 unwinds the sheet material that will become the filter sheet 13, and the fourth winding roll 54 unwinds the sheet material that will become the inner nonwoven fabric 12. A guide member 60 is provided upstream of the polymerization roller 70 so that the sheet materials 11, 14, 13, and 12 unwinded from the respective winding rollers 51, 52, 53, and 54 are properly introduced into the polymerization roller 70.

[0044] One guide member 60 is provided for each of the four sheet materials unwound from the winding rolls 51, 52, 53, and 54. FIG. 7 shows an enlarged view of the periphery of the guide member 60 in the nonwoven mask manufacturing apparatus of FIG. 6. As shown in FIG. 7, each guide member 60 has a pair of guide grooves 60a. These guide grooves 60a regulate the edges on both sides of the sheet materials 11, 14, 13, and 12, so that the sheet materials 11, 14, 13, and 12 are introduced into the polymerization roller 70 (FIG. 6) while being positioned relative to each other in the direction of arrow A (the direction corresponding to the vertical width W2 (FIG. 3) of the mask body 10).

[0045] As already mentioned, in the nonwoven mask of this embodiment, the vertical width W3 (FIG. 3) of the shape-retaining mask 14 is narrower than the vertical width W2 (FIG. 3) of the mask body 10. Therefore, the width of the sheet material (shape-retaining sheet 14) wound on the second winding roll 52 is also narrower than the widths of the sheet materials (outer nonwoven fabric 11, inner nonwoven fabric 12, and filter sheet 13) wound on the other winding rolls 51, 53, and 54. As such, it is not necessarily easy to introduce the sheet material 14, which is narrower than the other sheet materials 11, 12, and 13, into the polymerization roller 70 while accurately positioning it. However, this problem is solved by making the guide member 62 (FIG. 6) for the shape-retaining sheet 14 narrower than the other guide members 61, 63, and 64 (FIG. 6).

[0046] As shown in FIG. 6, four folding guides 81, 82, 83, and 84 (only one of which is visible in the figure) are provided downstream of the polymerization roller 70 and are arranged substantially parallel to one another. These four folding guides 81, 82, 83, and 84 fold back predetermined portions of the four sheet materials (outer nonwoven fabric 11, inner nonwoven fabric 12, filter sheet 13, and shape-retaining sheet 14). A pair of upper and lower straightening rollers 90 are provided downstream of the folding guides 81, 82, 83, and 84. The four sheet materials 11, 12, 13, and 14, which have been folded back at predetermined portions by the folding guides 81, 82, 83, and 84, are passed through gaps between the straightening rollers 90 to form creases in the folded portions. These creases become the pleats P1, P2, P3, and P4 described above (FIGS. 4 and 5).

[0047] After passing through the straightening roller 90, the four sheets of sheet material are welded together at predetermined locations (locations corresponding to weld lines L1, L2, L3, L4, and L5 in FIG. 3) by a welding roller (not shown). Downstream of the welding roller, a cutting roller (not shown) is provided, and the four sheets of sheet material are cut into predetermined lengths (lengths corresponding to the left-right width W1 of the mask body 10 in FIG. 2). Each cut piece of fabric becomes the mask body 10. After cutting, folding members 15 (FIG. 4) are inserted into the mask body 10, and ear loops 20 (FIG. 3) are welded to complete the nonwoven fabric mask.

[0048] By manufacturing a nonwoven fabric mask in this manner, when overlapping the outer nonwoven fabric 11, the inner nonwoven fabric 12, and the filter sheet 13, the shape-retaining sheet 14 can also be overlapped together. This eliminates the need for a separate process for inserting the shape-retaining sheet 14 into the gap between the outer nonwoven fabric 11 and the inner nonwoven fabric 12. This makes it possible to easily manufacture a nonwoven fabric mask that has the function of keeping the mask body 10 inflated outward when worn. [Explanation of symbols]

[0049] 10 Mask body 10a Sheath 10b Slit 11 Outer non-woven fabric 12 Inner non-woven fabric 13 filter sheet 14 Shape-retaining sheet 15 Bending member 16 Shape-retaining wire 20 Ear hook 51 First Winding Roll 52 Second winding roll 53 Third Winding Roll 54 Fourth Winding Roll 60 Guide member 60a Guide groove 61 first guide member 62 second guide member 63 Third guide member 64 Fourth guide member 70 Polymerization Roller 81 First Folding Guide 82 Second Fold Guide 83 Third Fold Guide 84 Fourth Fold Guide 90 Shaping roller L1 welding wire L2 welding wire L3 welding wire L4 welding wire L5 welding wire L6 welding wire L7 welding wire P pleats P1 pleats (first row) P2 pleats (second row) P3 pleats (3rd row) P4 pleats (fourth row) W1 mask body width W2 mask body vertical width W3 Shape-retaining sheet vertical width W4 shape-retaining sheet width α1: A planar area that roughly crosses the middle part of the mask body in the left-right direction β1 mountain fold β2 valley fold

Claims

1. The mask body is An outer nonwoven fabric that forms the outer surface of the mask body; An inner nonwoven fabric that forms the inner surface of the mask body; A filter sheet disposed in the gap space between the outer nonwoven fabric and the inner nonwoven fabric; A nonwoven mask constructed by layering The mask body has a plurality of pleats extending along the left-right direction, A shape-retaining sheet extending in the vertical and horizontal directions is disposed in the gap space so as to overlap a planar region that substantially crosses the middle portion of the mask body in the horizontal direction, A shape-retaining sheet is arranged so as to overlap at least one of the plurality of pleats, and a crease is also formed in the shape-retaining sheet at the location where the shape-retaining sheet overlaps the pleat, The vertical width of the shape-retaining sheet after folding is 20 mm or more and 0.8 times or less than the vertical width of the mask body, The left and right width of the shape-retaining sheet is approximately equal to the left and right width of the mask body. A nonwoven mask characterized by:

2. 2. The nonwoven fabric mask according to claim 1, wherein the shape-retaining sheet is a woven fabric or a nonwoven fabric.

3. 3. The nonwoven mask according to claim 2, wherein the shape-retaining sheet is a resin fiber fused nonwoven fabric in which a large number of short fibers made of a thermoplastic resin are fused to each other.

4. The nonwoven mask according to any one of claims 1 to 3, wherein the left and right edges of the shape-retaining sheet are welded to the left and right edges of the outer nonwoven fabric and the inner nonwoven fabric.

5. The nonwoven fabric mask according to any one of claims 1 to 4, wherein a shape-retaining sheet is disposed between the outer nonwoven fabric and the filter sheet.

6. A method for manufacturing a nonwoven fabric mask, comprising the steps of: manufacturing the nonwoven fabric mask according to any one of claims 1 to 5;

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