JP7676250B2 - mask - Google Patents

Description

The present invention relates to a mask that is comfortable to wear, has excellent adhesion, and does not lose its shape even after repeated use.

In general, masks that cover the nose and mouth are widely used to prevent infectious diseases, hay fever, and the like. A wide variety of such masks have been proposed to meet different needs, and the following, for example, are known as disposable masks made of nonwoven fabric sheets.

Japanese Patent Application Publication No. 11-114080 Japanese Utility Model Application Publication No. 60-113057 Utility Model Registration No. 3172588 JP 2005-95370 A

The masks in Patent Documents 1 and 2 are made by cutting a nonwoven fabric sheet into a specified shape, and integrally forming a mask part that covers the area from the nose to the mouth, and engagement parts that engage with the left and right ears. However, because the flat sheet is worn by fitting it to the uneven surface of the face, prioritizing adhesion places a large burden on the ears, and the mask also fits tightly around the mouth, making it difficult to breathe. Furthermore, because the masks are intended to be disposable, there is the problem that the engagement parts that engage with the ears easily stretch and deform, and deformation reduces the effectiveness of the fit.

On the other hand, the mask in Patent Document 3 does not fit the entire nonwoven fabric sheet to the face, but instead has wires in the top and left and right edges of the mask, which is folded to give it a three-dimensional appearance, to improve adhesion. However, not only is it time-consuming and costly to manufacture, but it is also time-consuming to wear the mask, as the three wire parts must be aligned to the face. Furthermore, if the wire parts become distorted, they will no longer fit the face, making it difficult to reuse the mask once it has been removed.

The mask in Patent Document 4 aims to achieve both a good fit and a comfortable fit by using a special nonwoven fabric sheet with excellent elasticity. However, because the holes for engaging with the ears are long and thin, there is a feeling of tension. In addition, because the area of the part that covers the cheeks is large, there is also the problem that it does not provide a cooling sensation, and improvements in these areas are required.

The present invention has been made in consideration of these circumstances, and aims to provide an excellent mask that adheres well to the face, is comfortable to wear, does not cause pain behind the ears in particular, and does not lose its shape even when put on and taken off repeatedly.

To achieve the above object, the first gist of the present invention is a mask made of a single layer of polyurethane elastic nonwoven fabric, used to cover the nose and mouth, comprising a central portion that covers the nose and mouth when worn, and a pair of left and right ear engagement portions that extend laterally from the central portion and engage with the ears when worn, each of the pair of left and right ear engagement portions having an opening for engaging the ears, with the first opening portion located closest to the center of the mask being approximately isosceles triangular in shape with its apex pointing toward the center of the mask, the second opening portion extending laterally from the first opening portion being rectangular in shape with upper and lower opening edges extending parallel to each other, and the third opening portion extending laterally from the second opening portion being approximately partially circular.

The second gist of the present invention is a mask in which a welded portion is provided along an imaginary center line P that extends vertically through the center of the central portion, and the welded portion gives the mask a three-dimensional shape. The third gist of the present invention is a mask in which the welded portion has a width dimension d, which is transverse to the longitudinal direction, of 0.1 to 1.5 mm.

In particular, a fourth aspect of the present invention is a mask in which the angle θ at the apex corner of the first opening portion at the opening of the ear engagement portion is 30 to 80°, and a fifth aspect of the present invention is a mask in which the apex corner of the first opening portion at the opening of the ear engagement portion is rounded with a radius of curvature _R1 of 1 to 10 mm.

Furthermore, a sixth aspect of the present invention is a mask in which, at the opening of the ear engagement portion, the length dimension _L1 extending to the left and right of the second opening portion is 20 to 40 mm, and the ratio ( _L1 / _L0 ) of _L1 to the total length _L0 in the left and right direction when the mask is stretched flat on a plane is 0.05 to 0.14.A seventh aspect of the present invention is a mask in which, at the opening of the ear engagement portion, the radius of curvature _R2 of the arc portion of the approximately partially circular shape of the third opening portion is 20 to 30 mm.

Furthermore, an eighth aspect of the present invention is a mask in which the polyurethane elastic nonwoven fabric has the following properties (1) to (4):
(1) Weight: 60 to 120 g/ ^m2
(2) Tensile strength in the machine direction (MD direction) and cross direction (CD direction): both 1000 cN/20 mm or more (3) Tensile elongation in the machine direction and cross direction: both 300% or more (4) 100% elongation recovery rate in the machine direction and cross direction: both 90% or more

And, in the mask according to the eighth aspect of the present invention, in a ninth aspect, the mask is one in which the polyurethane elastic nonwoven fabric further has the following properties (5) and (6):
(5) Air permeability: 50 cc/cm ² /sec or more (6) Maximum heat absorption rate (Q-max): 0.08 or more

That is, since the mask of the present invention is entirely made of a single layer of elastic polyurethane nonwoven fabric, it has excellent elasticity and excellent wearing comfort and adhesion to the face.
In addition, the openings for engaging with the ears on the ear engaging parts that extend to the left and right have a unique shape that has not been seen before, so the area around the mouth does not feel cramped and a tight fit is maintained. In addition, because the openings are large in the areas that overlap with the cheeks, there is no feeling of pressure from the mask fabric, and it has the advantage of providing a cool feeling even when the outside temperature is high.
The effects of each part of the opening will now be described in more detail.

(1) Effect of the first opening portion of the opening being approximately isosceles triangular in shape: The portion extending from the portion that engages with the ears to the central portion that covers the nose and mouth is divided into upper and lower portions by the first opening portion, so that the lower edge portion that rests on the lower jaw and the upper end portion that rests on the nose are pulled in the left and right directions, respectively, and are kept in close contact with the face, making it difficult for slack to occur in the fabric, while the area near the center of the central portion from the nose to the mouth is not affected, and the mouth can be opened and closed relatively freely. This results in an excellent wearing comfort.

(2) Effect of the second opening part of the opening being rectangular This part of the mask that overlaps with the cheeks is a large rectangular opening, so the skin on the cheeks is not pressed by the mask fabric, making it comfortable to wear. It also makes it less stuffy, and provides a cool feeling even when the outside temperature is high.

(3) Effect of the third opening part of the opening being approximately partially circular The upper and lower ends of the approximately partially circular shape are connected to the upper and lower opening edges that extend in parallel to the second opening part, and these opening edges that extend in the upper, lower, left and right directions expand and contract to maintain the mask's adhesion to the face. The tensile stress generated by the upper and lower opening edges being pulled is dispersed by the arc-shaped opening edges that come into contact with the back of the ears, and is not concentrated at one point, so that the back of the ears is less likely to hurt.

In particular, among the present inventions, those in which a welded portion is provided along an imaginary center line P that extends vertically through the center of the central portion, and the welded portion gives the mask a three-dimensional shape, are preferable because the mask can easily conform to the contours of the face and there is more space around the nose and mouth.

In particular, among the present invention, the welded portion has a width dimension d of 0.1 to 1.5 mm in the transverse direction across the longitudinal direction. This makes the welded portion less noticeable in the center of the front of the mask, resulting in a good appearance, since the width dimension d of the welded portion is very small. In addition, the presence of the welded portion does not reduce the comfort of the mask, and the welded portion is less likely to damage the fabric when washed, making this mask suitable.

Furthermore, in the present invention, when the angle θ at the apex of the first opening portion of the opening of the ear engagement portion is 30 to 80°, the pulling force applied to the ear engagement portion does not forcibly pull the portion connected to the central portion covering the nose and mouth in a diagonal direction, which is particularly preferable and provides a better wearing comfort. Moreover, since the mask shape easily fits the face, there is no looseness and the fabric is less likely to become loose, making it more hygienic and aesthetically pleasing.

In the present invention, when the apex corner of the first opening is rounded with a radius of curvature _R1 of 1 to 10 mm, even if the mask is used repeatedly, tensile stress is not concentrated at the tip of the apex corner, and this part is less likely to break. In addition, the shape of the apex corner is further suppressed, so that the mask as a whole does not lose its shape, which is preferable.

In the present invention, it is particularly preferable that the length dimension _L1 extending to the left and right of the second opening portion in the opening of the ear engagement portion is 20 to 40 mm, since this reduces the burden on the ears. Moreover, it is preferable that the ratio ( _L1 / _L0 ) of _L1 to the total length _L0 in the left and right direction when the mask is stretched flat on a plane is 0.05 to 0.14, since this reduces the feeling of pressure on the cheeks, and a cool feeling can be obtained even when the outside temperature is high.

In addition, in the present invention, it is particularly preferable that the radius of curvature _R2 of the arc portion in the approximately partially circular shape of the third opening portion in the opening of the ear engagement portion is 20 to 30 mm, since this further reduces the burden on the ear.

In particular, among the polyurethane elastic nonwoven fabrics of the present invention, those in which the following characteristics are set within a specified range: (1) basis weight, (2) tensile strength in the longitudinal direction (MD) and transverse direction (CD), (3) tensile elongation in the longitudinal direction and transverse direction, and (4) 100% elongation recovery rate in the longitudinal direction and transverse direction, are more suitable, since they have a better wearing comfort and adhesion to the face.

And among the masks according to the seventh aspect above, those in which the polyurethane elastic nonwoven fabric has the following characteristics set within a predetermined range: (5) breathability, (6) maximum heat absorption rate (Q-max), are particularly suitable as they are easier to breathe, less likely to become stuffy, and have an even improved feeling of coolness.

1 is a perspective view showing a mask according to an embodiment of the present invention; FIG. 2A is an explanatory diagram showing the mask when it is stretched out flat, and FIG. 2B is an explanatory diagram showing one side of the mask when it is folded in half at the center. FIG. 2 is a plan view showing the polyurethane elastic nonwoven fabric used in the above mask cut for use in the mask. FIG. 2A is a schematic explanatory diagram showing the shapes of the left and right openings of the mask, and FIGS. 2B and 2C are schematic explanatory diagrams showing modified examples of the opening shapes in the mask. 13 is an explanatory diagram showing still another modified example of the opening shape in the mask. FIG.

Next, the form for implementing the present invention will be described in detail with reference to the drawings.

One embodiment of the mask of the present invention is shown in Figure 1. This mask is used to cover the nose and mouth, and is made by cutting a single layer of elastic polyurethane nonwoven fabric into a predetermined shape that is symmetrical on the left and right, and providing a welded portion 1 along an imaginary center line P that serves as the axis of symmetry, thereby giving it a three-dimensional shape.

To explain in more detail, the mask has a central section 2 that covers the nose and mouth when worn, and a pair of left and right ear engagement sections 3 that extend laterally from the central section 2 and engage with the ears when worn. Each of the pair of left and right ear engagement sections 3 has an opening 4 for engaging the mask with the ears.

The opening 4 has a first opening portion 5 located closest to the center of the mask, which is a roughly isosceles triangle with its apex facing the center of the mask, a second opening portion 6 extending laterally from the first opening portion 5, which is a rectangle with upper and lower opening edges extending parallel to each other, and a third opening portion 7 extending laterally from the second opening portion 6, which is semicircular.

The welded portion 1 extends upward from a position (indicated by O in FIG. 1) that is approximately the center in the vertical direction of a center line P that extends vertically through the center of the central portion 2 of the mask, and the portion below the welded portion 1 is simply a fold (a so-called "loop").

When the mask is laid out flat, its planar shape is as shown in Figure 2(a). At this time, the part through which the imaginary center line P passes is bulged out to cover the nose area by the welded part 1, and this bulged part is shown folded over to the left (the bulged part is shown with diagonal lines S). Also, if the entire mask is folded in half along the center line P and placed with the right side facing up, it will look like Figure 2(b).

As can be seen from these figures, the left and right upper edge portions 8 extending from the central portion 2 toward the left and right ear engagement portions 3 are highest in the center and slope downward toward the boundary between the first opening portion 5 and the second opening portion 6 of the left and right openings 4. Similarly, the left and right lower edge portions 9 are lowest in the center and slope upward toward the boundary between the first opening portion 5 and the second opening portion 6 of the left and right openings 4.

The welded part 1 extending along the center line P of the central part 2 is curved in a gentle arc, and the folded part below the welded part 1 is naturally straight. In this way, when the upper part along the center line P where the welded part 1 is provided is curved in an arc, this part fits the nose and the mask is less likely to slip off. Also, when the lower part along the center line P is straight, the fabric does not slacken, and the mask is less likely to slip off the lower chin.

The above mask can be obtained, for example, as follows. First, a polyurethane elastic nonwoven fabric that is stretchable, breathable, and equipped with a specified filtering function (such as pollen prevention or splash prevention) is prepared, and cut or welded into the shape shown in Figure 3. This shape is symmetrical about the center line P, and a large cutout 10 is provided in the upper center so that after welding, the central portion will have a three-dimensional shape that bulges forward. By welding the curved left and right edges of this cutout 10, a mask with the shape shown in Figures 1 and 2 can be obtained.

The mask obtained in this way is entirely made of a single layer of polyurethane elastic nonwoven fabric, so it has excellent elasticity and excellent fit and fit to the face. And because the central part 2 bulges forward, there is space from the nose to the mouth, making it easy to breathe and move the mouth.

In particular, the first opening 5 of the opening 4 for engaging with the ear is shaped like an isosceles triangle with the apex angle facing the center, so that the portion extending from the ear engaging portion 3 to the central portion 2 covering the nose and mouth is divided into upper and lower portions by the first opening 5. With this configuration, the lower edge 9 that rests on the lower jaw and the upper end 8 that rests from the nose to the cheeks are pulled left and right, respectively, maintaining a tight fit to the face, while the central portion between them, from the nose to the mouth, is less susceptible to the effects of the pulling force, providing an advantage in that there is more space around the mouth in particular.

In addition, the second opening 6 of the opening 4 is rectangular, and the part that overlaps with the cheek is open wide, so the skin on the cheek is not pressed by the mask fabric, making it more comfortable to wear. And because the contact area with the mask fabric is small, it is less likely to become stuffy, and has the advantage of providing a cool feeling even when the outside temperature is high.

Furthermore, the third opening portion 7 of the opening 4 is semicircular, and the semicircular opening edge is connected to the upper and lower opening edges of the second opening portion 6, which extend in parallel. Therefore, even if the semicircular opening edge that touches the back of the ear is pulled as the upper and lower opening edges expand and contract, the pulling force is distributed to each part of the semicircular shape and is not concentrated at one point, so that the back of the ear is less likely to hurt.

The polyurethane elastic nonwoven fabric used in the above mask is a nonwoven fabric made of polyurethane elastic fibers. Polyurethane elastic fibers are more flexible than other fibers such as polypropylene, and have the advantage of being less susceptible to heat buildup inside the mask due to their high thermal conductivity.

The polyurethane elastic nonwoven fabric does not have to be entirely made of polyurethane elastic fibers, and may be partially replaced with other fibers. However, in order to ensure the elasticity, flexibility, etc. required for the mask, if other fibers are used, it is desirable to set the proportion of such fibers to 10% by mass or less of the total fibers.

The thickness of the polyurethane elastic fibers used in the polyurethane elastic nonwoven fabric is not particularly limited, but in consideration of the pollen and droplet removal performance, it is desirable for the fiber diameter to be as small as possible so that dense air holes can be formed, and in consideration of the overall strength, elasticity, breathability, etc., the average fiber diameter is 25 μm or less, preferably 5 to 15 μm, and more preferably 8 to 12 μm.

Furthermore, in order to obtain a good wearing comfort and sufficient adhesion, it is preferable that the above-mentioned polyurethane elastic nonwoven fabric has the following properties (1) to (4).
(1) Weight per unit area: 60 to 120 g/m ² , particularly 80 to 120 g/m ² , and furthermore 90 to 110 g/m ²
(2) Tensile strength in the machine direction (MD direction) and the cross direction (CD direction): both 1000 cN/20 mm or more. In particular, the machine direction tensile strength is 1200 cN/20 mm or more, and even 1600 cN/20 mm or more. In particular, the cross direction (CD direction) tensile strength is 1600 cN/20 mm or more, and even 1800 cN/20 mm or more. (3) Tensile elongation in the machine direction and the cross direction: both 300% or more, and especially 350 to 520%.
(4) 100% elongation recovery rate in both the longitudinal and transverse directions: 90% or more, especially 94-100%

The above "tensile strength" and "tensile elongation" are values measured in accordance with JIS L1913:2010 6.3.1, and the above "100% elongation recovery rate" is a value measured in accordance with JIS L1096:2010 8.16.2.

In order to obtain a better wearing feeling, it is preferable that the polyurethane elastic nonwoven fabric further has the following properties (5) and (6). The upper limit of the air permeability is appropriately set depending on the required filter performance, etc. The maximum heat absorption rate (Q-max) is an index of the degree of coldness felt when touched, and the higher the value, the stronger the cold feeling obtained, which is preferable.
(5) Air permeability: 50 cc/cm ² /sec or more; (6) Maximum heat absorption rate (Q-max): 0.08 or more, preferably 0.10 or more.

The above "breathability" is a value measured in accordance with JIS L1913:2010 6.8.1 Frazier method, and the above "maximum heat absorption rate (Q-max)" is a value measured in accordance with JIS L1927:2020.

The polyurethane elastic nonwoven fabric with such characteristics is most preferably obtained by the melt blowing method. To explain this method in more detail, for example, a spinning device described in JP-B-41-7883 is used, and a thermoplastic polyurethane elastomer is melt-discharged from the spinneret, and an accelerated gas flow is sprayed from both sides of the nozzle to thin the filaments. The thinned filaments are then separated from the gas flow and stacked on a collection device such as a moving conveyor net, and are cooled and solidified while being bonded at their contact points. Of course, after cooling and solidifying on the collection device, the filaments may be bonded by heating and pressing using a roller or the like. The polyurethane elastic nonwoven fabric obtained in this way has a structure in which thin continuous filaments of polyurethane elastic fiber are randomly stacked, and therefore has excellent breathability, dense filtering function, high elasticity, and flexibility.

The polyurethane elastic nonwoven fabric may be one that has been given antibacterial or bactericidal properties. Those that have been given antibacterial properties are hygienic as they inhibit the growth of germs. And those that have been given bactericidal properties can prevent the invasion of germs from the outside, so they can be used for special purposes.

Furthermore, the polyurethane elastic nonwoven fabric may be one that has been given electrical conductivity. By giving the mask electrical conductivity, static electricity will not build up, so it will not attract dust or dirt, making it more hygienic.

The mask of the present invention is resistant to deformation due to its material and shape. Therefore, it is suitable for repeated use after washing rather than being thrown away. For this reason, it is desirable that the shape of the polyurethane elastic nonwoven fabric after, for example, 10 home washes (in accordance with JIS L1930:2014 C4M method) remains as unchanged as possible compared to the shape before washing.

In the above example, the welded part 1 is provided along the imaginary center line P that extends vertically through the center of the mask in the central part 2, and the welded part 1 gives the mask a three-dimensional shape, but the welded part 1 is not necessarily required. That is, even if the mask is made of a single flat piece of fabric (polyurethane elastic nonwoven fabric), the elasticity of the polyurethane elastic nonwoven fabric is good, and as mentioned above, the shape of the openings 4 provided in the ear engagement parts 3 on both sides of the mask is special, so even if the welded part 1 is not provided, the upper edge 8 of the mask is pressed against the part that crosses the nose, and the lower edge 9 of the mask is pressed against the chin, and the central fabric from the nose to the mouth is pushed forward, creating a gap. As a result, the mask periphery fits closely along the contours of the face, just like a three-dimensional mask, and the mask is roomy in the center and comfortable to breathe in.

When the welded portion 1 is provided as in the above example, the degree of freedom of the fabric in the space around the mouth is easily affected by the arrangement of the arc-shaped upper portion 15 with the welded portion 1 provided and the linear lower portion 16 below it, so it is preferable that the arc-shaped upper portion 15 passes vertically from the nose to the mouth [see FIG. 2(b)]. It is also preferable that the linear lower portion 16 reaches from below the mouth to the chin. To achieve this, it is preferable that the ratio (A/B) of the length dimension A of the upper portion 15 to the length dimension B of the lower portion 16 is 4/6 to 6/4, and more preferably 4.3/5.7 to 5.7/4.3. In other words, it is preferable that the position O, which is the switching point between the upper portion 15 and the lower portion 16, is located near the center in the vertical direction of the fold portion.

And, as in the above example, when the welded portion 1 is provided in the center of the mask, even if the welded portion 1 is not made rigid to function as a rib, the central fabric from the nose to the mouth is pushed forward as described above, so there is no need to set the width dimension d [see FIG. 2(b)] of the welded portion 1 across the longitudinal direction to a wide value. In other words, by providing the welded portion 1, the fabric can be welded to obtain a more stable three-dimensional effect, but since high rigidity as a rib is not required, the width dimension d is preferably set to, for example, 2 mm or less, and especially 0.1 to 1.5 mm. In this way, by making the width dimension of the welded portion 1 very narrow, the welded portion 1 is not noticeable in the center of the mask, resulting in a good-looking appearance. In addition, since the welded portion is not stiff, combined with the size of the ear engagement openings 4, it is possible to obtain an excellent wearing comfort and cool feeling.

When the welded portion 1 is provided, it is preferable that the welded portion 1 is formed in the region from the center of the mask to the upper half region as in the above example. In this case, the edge portion that becomes the welded portion 1 may be straight, but as shown in the above example, it is preferable that it is curved in an arc shape, and the radius of curvature R ₃ of the arc shape [see FIG. 2(b)] is usually set to 100 to 150 mm, and preferably 120 to 135 mm, depending on the longitudinal dimension of the welded portion 1. In other words, by making the welded portion 1 an arc shape with an appropriate radius of curvature rather than a straight line, the three-dimensional bulging shape from the nose to the mouth is controlled to improve the wearing comfort and the close contact.

The straight line portion below the welded portion 1, which was not welded in the above example, may also be welded to form a continuous welded portion 1 from the top to the bottom. Alternatively, the arc-shaped upper welded portion 1 and the straight line-shaped lower welded portion may be spaced apart from each other, with the area between them left unwelded and with a fold. When forming a continuous welded portion 1, it is not necessary to fold a single sheet of nonwoven fabric in half and weld the fold, but two sheets of a pair of left and right nonwoven fabrics may be overlapped and the overlapping edges may be welded.

In the above example, the angle θ [see FIG. 2(b)] at the apex of the first opening 5 of the opening 4 of the ear engagement part 3 is set appropriately, but is preferably 30 to 80°, more preferably 40 to 70°, and particularly preferably 50 to 65°. In other words, if the angle θ is too large, the effect of dividing the pulling force generated from the ear engagement part 3 of the mask toward the central part 2 into upper and lower parts and suppressing the influence on the central part 2 is reduced, which is not preferable. If the angle θ is too small, it is necessary to reduce the upper and lower widths of the ear engagement part 3 or to increase the width W of the fabric at the ear engagement part 3 (the width between the outline edge of the ear engagement part 3 and the edge of the opening, see FIG. 3), which may cause a poor wearing comfort around the ears, which is not preferable.

Furthermore, in the opening 4 of the ear engagement portion 3, it is not essential to provide a radius at the apex corner of the first opening portion 5, but it is desirable to provide a radius because, if this portion is not provided with a radius, the fabric in this portion may stretch and become loose or tear after repeated use and washing. The radius of curvature R ₁ (see FIG. 3) of the radius is preferably 1 to 10 mm, and more preferably 2 to 5 mm. If the radius is too large, the effect of dividing the tensile force on the fabric into upper and lower parts due to the approximately isosceles triangular shape of the first opening portion 5 is weakened, which is undesirable.

In the above example, the apex corners of the first opening portion 5 are arranged to face each other toward the center line P of the mask, but in the present invention, the state in which the apex corners are "facing the center of the mask" does not necessarily mean that the apex corners are arranged to face perpendicular to the center line P of the mask as shown in FIG. 4(a), but also includes, for example, an arrangement in which the apex corners are slightly downward relative to the center line P as shown in FIG. 4(b), or an arrangement in which the apex corners are slightly upward relative to the center line P as shown in FIG. 4(c).

However, the shape of the apex angle shown in Figures 4(b) and (c) is tilted at a large angle for the purpose of explanation. In reality, if the direction in which the bisector D of the apex angle in Figure 4(a) extends is taken as 0°, then in Figures 4(b) and (c), each bisector D1, D2 should be tilted at an angle of within ±10°, which is preferable in order to prevent sagging in the mask.

In the state shown in FIG. 4(b) or the state shown in FIG. 4(c), the first opening portion 5 is not an "isosceles triangle" and one side of the apex angle is slightly longer than the other side, but in the present invention, these shapes are also included in the "approximately isosceles triangle".

Similarly, the length dimension L ₁ [see FIG. 2(a)] extending to the left and right of the second opening portion 6 in the opening 4 of the ear engagement portion 3 is usually set to 20 to 40 mm, although it depends on the size of the entire mask. The ratio (L 1 /L ₀ ) of L ₁ to the total mask length L ₀ in the left and right direction when the mask is stretched flat on a plane [as shown in FIG. ₂ (a)] is preferably 0.05 to 0.14, more preferably 0.085 to 0.12, and even more preferably 0.09 to 0.11. That is, if the ratio (L ₁ /L ₀ ) is too small, the opening of the second opening portion 6 may become narrow, causing a feeling of pressure, whereas if it is too large, the ear engagement portion 3 may become too long or the central portion 2 may become too short in the left and right direction, causing the overall balance to deteriorate.

Similarly, in the above example, the third opening 7 of the opening 4 of the ear engagement portion 3 is semicircular (a partial circle with a central angle of 180°), but it does not necessarily have to be semicircular, and may be a partial circle with a central angle θ' smaller than 180°, as shown in FIG. 5. However, in order to enlarge the opening of the third opening 7 to provide a superior wearing sensation, particularly a cool feeling, and to avoid discomfort when engaging with the ear, it is preferable to set the radius of curvature R ₂ (return to FIG. 3) of the arc portion in the partial circle shape to be, for example, 20 to 30 mm, and more preferably 23 to 28 mm, taking into account the wearing sensation when engaging with the ear, although there is a balance with the central angle.

Furthermore, the third opening 7 does not have to be a partial circle of a perfect circle as described above, but may be an ellipse that is slightly crushed in the vertical direction, an ellipse that is slightly crushed in the horizontal direction, or an approximation of a circle that is not an ellipse but is a partial circle that is different from a perfect circle. In the present invention, these are collectively referred to as "approximately partial circles". In other words, in the mask of the present invention, it is important that the opening shape of this third opening is an approximately partial circle without corners in order to obtain a comfortable fit and a cool feeling when it engages with the ears.

In addition, as described above, when the third opening portion 7 is not a partial circle of a perfect circle, the "radius of curvature R ₂ of the arc portion" is defined as the radius of curvature R ₂ at a position in the arc portion of the third opening portion 7 opposite the apex angle of the first opening portion 5.

The width W of the ear-engaging portion 3 (shown by the hatched portion T in FIG. 3) that is narrowed by the opening 4 depends on the contour shape of the mask and the shape of the opening 4. To obtain a comfortable fit when worn on the ear, it is preferable that the width W is approximately the same in all parts. In particular, it is preferable that the contour is approximately parallel to the curve of the third opening 7, because this is less likely to cause stress to concentrate locally when worn on the ear, making it more likely to tear or cause ear pain. The width W is usually preferably 3 to 15 mm, and is preferably set to 5 to 15 mm, and more preferably 8 to 12 mm. If the width W is too large, this portion may twist and the fit to the ear may be reduced. Conversely, if the width W is too small, it is not preferable because the mask will hit the ear or cheek too hard, making the fit less comfortable or the portion may be more likely to tear.

Next, the present invention will be described based on examples and comparative examples. However, the present invention is not limited to the following examples.

First, four types of polyurethane elastic nonwoven fabrics A to D with different physical properties were prepared as mask fabrics. The physical properties of each nonwoven fabric are shown in Table 1 below.
The polyurethane elastic nonwoven fabrics A to C are made by melt-blowing a polyurethane elastomer made of diphenylmethane diisocyanate, polyol, and 1,4-butanediol. The polyurethane elastic nonwoven fabric D is the polyurethane elastic nonwoven fabric described in JP 2005-95370 A.

In addition, in Table 1 above, "Pollen prevention performance (removal rate)" is a value calculated in accordance with the method stipulated by the National Mask Industry Association of the Japan Hygiene Materials Industry Association as the "Pollen particle collection (filtration) efficiency test method."

[Examples 1 to 6, Comparative Examples 1 to 3]
Using the nonwoven fabrics A to D, nine types of masks (Examples 1 to 6, Comparative Examples 1 to 3) having the characteristics shown in Tables 2 and 3 were produced. The masks were arranged so that the longitudinal direction was the transverse direction (CD direction) of the nonwoven fabric, and a high-frequency welder was used to first melt-cut the fabric shape that would become the mask (see FIG. 3), and then, with the fabric folded in half and overlapped, melt-cut and melt-bonded the portions to be welded (notch 10 in FIG. 3).
Comparative Example 1 is a disposable mask having the shape shown in FIG. 1 of JP 2005-95370 A, and the physical properties of the fabric are based on the values shown in Example 1 of the above publication. Comparative Example 2 is a mask similar to Example 1, except that the first opening portion of the opening is semicircular like the third opening portion. Comparative Example 3 is a mask similar to Example 1, except that the second opening portion of the opening is not provided, and the approximately isosceles triangular opening of the first opening portion is extended horizontally and connected to the third opening portion.

These example products and comparative example products were evaluated for the following items according to the procedures below, and the results are shown in Tables 2 and 3 below.

[Wearing comfort, etc.]
Eleven monitors were asked to wear each mask for a day from 10am to 6pm, except when eating or drinking, and were asked to evaluate the four items of fit to the face, comfort of the ear loop, freedom of movement around the mouth when opening and closing, and coolness to the face on a four-point scale: ◎...very good, ○...good, △...average, ×...bad, with the most common evaluation being recorded. If the same number of people gave the same evaluation, the two evaluations were re-evaluated by all participants.

[Washing resistance (whether or not the shape is distorted)]
In accordance with the JIS L1930:2014 C4M method, after 10 home washes, the garments were visually observed for deformation and rated on a four-point scale: ◎: no deformation at all, ○: almost no deformation, △: some parts are deformed upon close inspection, ×: deformation is immediately apparent.

From the above results, it is seen that all of the example products have a good wearing feeling, a cool feeling, etc., and do not lose their shape even after 10 home washes, and can be used repeatedly with good results.
On the other hand, the opening of the ear hook of the comparative example 1 is narrow, which hurts the ears and does not feel cool. Also, it is assumed to be disposable, and the shape around the welded part is greatly distorted. Also, the opening shape of the ear hook of the comparative example 2 and 3 is different from the configuration of the present invention, so it is found that the wearing comfort is inferior to the example product.

The present invention can be widely used as a reusable mask that combines excellent adhesion and comfort, does not feel oppressive to the face, and has an excellent cooling sensation.

2 Central part 3 Ear engaging part 4 Opening 5 First opening part 6 Second opening part 7 Third opening part

Claims (7)

A mask made of a single layer of polyurethane elastic nonwoven fabric and used to cover the nose and mouth,
The mask has a central portion that covers the nose and mouth when worn, and a pair of left and right ear engagement portions that extend laterally from the central portion and engage with the ears when worn,
A welded portion is provided along an imaginary center line P extending vertically through the center of the central portion, and a three-dimensional shape is imparted by the welded portion,
The welded portion extends upward from a position that is approximately the center of the center line P in the up-down direction,
In the central portion of the mask, a ratio (A/B) of a dimension A of an arc-shaped upper portion having a welded portion along the center line P to a dimension B of a linear lower portion therebelow is 4/6 to 6/4;
Each of the pair of left and right ear engagement portions is provided with an opening for ear engagement,
The opening has a first opening portion located closest to the mask center and having a substantially isosceles triangular shape with an apex angle facing the mask center, a second opening portion extending laterally from the first opening portion and having a rectangular shape with upper and lower opening edges extending parallel to each other, and a third opening portion extending laterally from the second opening portion and having a substantially partial circular shape ,
A mask characterized in that, at the opening of the ear engagement portion, a length dimension L1 extending to the left and right of the second opening portion _is 20 to 40 mm, and the ratio (L1/L0) of _L1 to _{the total} length _L0 in the left and right direction when the mask is stretched flat on a plane is 0.05 to 0.14 . 2. The mask according to claim 1 , wherein the welded portion has a width dimension d of 0.1 to 1.5 mm in a width direction transverse to the longitudinal direction. 3. The mask according to claim 1 , wherein the angle θ at the apex of the first opening portion at the opening of the ear engagement portion is 30 to 80 degrees. The mask according to any one of claims 1 to 3 , wherein the opening of the ear engagement portion has an apex corner of the first opening portion rounded with a radius of curvature _R1 of 1 to 10 mm. The mask according to any one of claims 1 to 4 , wherein the radius of curvature _R2 of the arcuate portion of the substantially partially circular third opening portion at the opening of the ear engagement portion is 20 to 30 mm. The mask according to any one of claims 1 to 5 , wherein the polyurethane elastic nonwoven fabric has the following properties (1) to (4).
(1) Weight: 60 to 120 g/ ^m2
(2) Tensile strength in the machine direction (MD direction) and cross direction (CD direction): both 1000 cN/20 mm or more (3) Tensile elongation in the machine direction and cross direction: both 300% or more (4) 100% elongation recovery rate in the machine direction and cross direction: both 90% or more The mask according to claim 6 , wherein the polyurethane elastic nonwoven fabric further has the following characteristics (5) and (6).
(5) Air permeability: 50 cc/cm ² /sec or more (6) Maximum heat absorption rate (Q-max): 0.08 or more

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