mask

Abstract

To provide a mask in which a bonding part giving a three-dimensional effect to the mask is inconspicuous and which is excellent in adhesion and wearing feeling.SOLUTION: A mask is formed of one layer of a polyurethane elastic non-woven fabric, and includes a center part 2 and ear engaging parts 3. In the center part, the whole mask is folded into two with a center line P as a fold, and then right and left faces of the mask overlap each other. In a folded portion, an upper part is in an arc shape which bulges outward, and a lower part is in a linear shape. A bonding part 1 with a width dimension d of 0.1 to 1.5 mm is provided along at least the arc-like folded portion in the fold, and a three-dimensional shape is given by the bonding part 1.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a mask that is comfortable to wear, has excellent adhesion, and also looks good. [Background technology]

[0002] In general, masks that cover the nose and mouth are widely used to prevent infectious diseases, hay fever, etc. A wide variety of such masks have been proposed according to needs, and the following, for example, is known as a disposable type mask made of a nonwoven fabric sheet. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-95370 A Summary of the Invention [Problem to be solved by the invention]

[0004] The mask in Patent Document 1 aims to achieve both adhesion and a comfortable fit by using a special nonwoven fabric sheet with excellent elasticity. As shown in Fig. 7, this mask has a high adhesion to the face, so in order to eliminate the feeling of pressure on the mouth, a welded part 20 with a width of 2 to 7 mm is provided in the center of the mask from the nose to the mouth, and the rigidity of this part is used to function as a rib that lifts the fabric.

[0005] However, the wide welded part 20 extends vertically in front of the face, which is unattractive. When carrying the mask in a bag or pocket, folding the welded part 20 reduces its function as a rib by folding it, so this part must be folded in an extended state, which is another problem. It is therefore not possible to fold the mask smaller than the length of the welded part 20 for storage.

[0006] Recently, masks that can be washed and reused have been widely used, such as those shown in FIG. 8, which are made entirely of a flexible sponge material and have a welding part 21 that extends vertically in the center of the mask (FIG. 8 shows the mask folded flat).

[0007] However, like the mask shown in Fig. 7, this mask also has the problem that unless the welded parts 21 are made wide to a certain extent (specifically, 2 mm or more), the fabric sticks to the mouth, making it difficult to breathe or speak. Therefore, the problem that the welded parts 21 are conspicuous and unattractive remains.

[0008] The present invention has been made in consideration of the above circumstances, and has an object to provide a mask in which the welded parts that give the mask a three-dimensional appearance are not noticeable, and which has excellent adhesion and comfort when worn. [Means for solving the problem]

[0009] In order to achieve the above object, a first gist of the present invention is a mask made of a single layer of elastic polyurethane nonwoven fabric and used to cover the nose and mouth, the mask 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, the mask is folded in half at the central portion along an imaginary center line P that extends vertically through the center, so that the left and right surfaces of the mask overlap each other, the upper portion of the fold in this overlapping state is an arc-shaped portion that bulges outward and the lower portion is linear, and a welded portion having a width dimension d of 0.1 to 1.5 mm is provided along at least the arc-shaped fold portion of the fold, and the welded portion gives the mask a three-dimensional shape.

[0010] In addition, the second gist of the present invention is a mask in which the ratio (A / B) of the length dimension A of the arc-shaped upper part to the length dimension B of the linear lower part at the fold portion is 4 / 6 to 6 / 4, and the third gist of the present invention is a mask in which the radius of curvature R3 of the arc-shaped at the fold portion is 100 to 150 mm.

[0011] A fourth aspect of the present invention is a mask in which an opening for ear engagement is provided in each of the pair of left and right ear engagement portions, and the opening has a first opening portion located closest to the center of the mask and has a substantially isosceles triangular shape with an apex corner facing toward the center of the mask, a second opening portion extending laterally from the first opening portion has 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 has a substantially partial circular shape.A fifth 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 portions is 30 to 80°.

[0012] A sixth aspect of the present invention is a mask in which the elastic polyurethane nonwoven fabric has the following properties (1) to (4): (1) Weight: 60-120g / m 2 (2) Tensile strength in both the machine direction (MD) and cross direction (CD): 1000cN / 20mm or more (3) Tensile elongation in both the longitudinal and transverse directions: 300% or more (4) 100% elongation recovery rate in both the vertical and horizontal directions: 90% or more

[0013] Furthermore, in a seventh aspect of the present invention, among the masks according to the sixth aspect, the mask is one in which the polyurethane elastic nonwoven fabric further has the following properties (5) and (6): (5) Air permeability: 50cc / cm 2 / sec or more (6) Maximum heat absorption rate (Q-max): 0.08 or more Effect of the Invention

[0014] 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. When the mask is folded in half along imaginary center line P in the center covering the nose and mouth, the upper part of the fold has a special shape that bulges outward in an arc, and the lower part is straight. Since a weld is provided at least in the arc-shaped fold, even if the fabric on both sides is pulled toward the ears when the mask is worn, there is extra fabric around the folds from the nose to the mouth, so that ample space is maintained.

[0015] Therefore, even if the welded portion formed at the fold does not perform the reinforcing function of a rib as in conventional masks, the fabric does not press against the mouth. Therefore, the width dimension d of the welded portion can be set to 0.1 to 1.5 mm, which is the minimum width that performs the welding function, and the welded portion extending to the center of the mask is not noticeable, resulting in a good-looking appearance. Moreover, since the width of the welded portion is narrow and this portion is not required to perform the reinforcing function of a rib, the entire mask, including the welded portion, can be folded up small, making it convenient to carry and store.

[0016] Among the present invention, those in which the ratio (A / B) of the length dimension A of the arc-shaped upper part to the length dimension B of the straight lower part at the fold portion is 4 / 6 to 6 / 4 are particularly preferred, as this creates a protrusion between the nose and mouth, making it easy to create an appropriate space and particularly reducing the feeling of pressure around the mouth.

[0017] Furthermore, among the masks of the present invention, those in which the radius of curvature R3 of the arc shape at the fold portion is 100 to 150 mm are particularly preferred, since this reduces the feeling of pressure around the mouth and also provides a more comfortable wearing sensation against the cheeks.

[0018] Furthermore, among the present invention, in particular, the pair of left and right ear engagement parts each have an opening for ear engagement, and the openings are given specific shapes at the first opening, the second opening, and the third opening, respectively, so that the mouth area is not cramped and the mask maintains a tight fit. In addition, since the opening is large at the part that overlaps with the cheek, there is no feeling of pressure from the mask fabric, and it is also suitable in that a cool feeling can be obtained even when the outside temperature is high. Furthermore, it has the advantage that the back of the ear is not easily hurt even when the ear engagement parts are hung on the ears.

[0019] Among them, in particular, the ear engaging opening has an angle θ of 30 to 80° at the apex of the first opening, which is particularly suitable since the pulling force applied to the ear engaging part does not forcibly pull the part connected to the center part covering the nose and mouth in a diagonal direction, resulting in a better wearing comfort. Moreover, the mask shape easily fits the face, so there is no looseness and the fabric is less likely to become loose, making it more hygienic and aesthetically pleasing.

[0020] In particular, among the polyurethane elastic nonwoven fabrics of the present invention, those in which each of the following properties is set within a prescribed 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 set within a prescribed range, have better wearing comfort and adhesion to the face, and are therefore preferred.

[0021] Among them, the polyurethane elastic nonwoven fabrics in which the properties of (5) breathability and (6) maximum heat absorption rate (Q-max) are set within a predetermined range are particularly suitable, as they are more breathable and less likely to become stuffy, and thus have an improved cooling sensation. [Brief description of the drawings]

[0022] [Figure 1] 1 is a perspective view showing a mask according to an embodiment of the present invention; [Diagram 2]FIG. 1(a) is a diagram showing the mask when laid out flat, and FIG. 1(b) is a diagram showing the mask when folded in half at the center. [Diagram 3] FIG. 2 is a plan view showing the polyurethane elastic nonwoven fabric used in the above mask cut for use in the mask. [Figure 4] 13(a) and 13(b) are explanatory views showing modified examples of the welded portion of the mask. [Diagram 5] 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. [Figure 6] 13 is an explanatory diagram showing still another modified example of the opening shape in the mask. FIG. [Figure 7] FIG. 13 is an explanatory diagram showing an example of a conventional product when worn. [Figure 8] FIG. 13 is an explanatory diagram showing another example of a conventional product folded in half. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Next, an embodiment of the present invention will be described in detail with reference to the drawings.

[0024] 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 symmetrical shape and providing a welded part 1 along an imaginary center line P, which is the axis of symmetry, to give it a three-dimensional shape.

[0025] More specifically, 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.

[0026] The opening 4 has a first opening portion 5 located closest to the center of the mask, which is approximately an isosceles triangle with its apex facing toward the center of the mask, a second opening portion 6 extending laterally from the first opening portion 5, which is rectangular 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.

[0027] In addition, the welded portion 1 extends along the upper portion 15 of the fold, above a position (indicated by O in FIG. 1) that is approximately the center in the vertical direction of the center line P that extends vertically through the center of the central portion 2 of the mask, and the lower portion 16 below the welded portion 1 is simply a fold (a so-called "loop").

[0028] When the above mask is laid flat on its sides, 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 the mask in Figure 2(b).

[0029] 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 vicinity of 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 vicinity of the boundary between the first opening portion 5 and the second opening portion 6 of the left and right openings 4.

[0030] The welded portion 1 extending along the upper portion 15 of the fold is curved in a gentle arc, and the portion extending along the lower portion 16 below the welded portion 1 is naturally straight.

[0031] 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 filter function (such as pollen prevention, splash prevention, etc.) is prepared and cut into a shape as shown in Fig. 3. This shape is symmetrical about a 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 edges on the left and right of this cutout 10, a mask with the shape shown in Figs. 1 and 2 can be obtained.

[0032] The mask obtained in this manner is entirely made of a single layer of elastic polyurethane nonwoven fabric, and therefore has excellent elasticity, comfort when worn, and adhesion to the face.

[0033] Moreover, when the central part 2 that covers the nose and mouth is folded in half along the imaginary center line P, the upper part 15 of the fold is an arc that bulges outward, and the lower part 16 is a straight line, creating a special shape, and since at least the arc-shaped part has the welded part 1, even if the fabric on the left and right sides is pulled toward the ears when wearing the mask, there is enough fabric around the folds from the nose to the mouth, and the amount of space is maintained. This makes it easy to breathe and move your mouth.

[0034] And since the welded part 1 formed at the fold does not have a reinforcing effect as a rib as in conventional masks, the width dimension d of the welded part 1 can be set to the minimum width that performs the welding function, and therefore the welded part 1 extending to the center of the mask is not noticeable, resulting in a good-looking appearance. Moreover, since the width of the welded part 1 is narrow and this part is not required to have a reinforcing effect as a rib, the whole mask including the welded part 1 can be folded up small, making it convenient to carry and store.

[0035] The polyurethane elastic nonwoven fabric used in the mask is a nonwoven fabric made of polyurethane elastic fibers. Polyurethane elastic fibers are more flexible than other fibers such as polypropylene, and have a high thermal conductivity, which has the advantage that heat is less likely to build up inside the mask.

[0036] 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 and flexibility required for a 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.

[0037] 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 that the fiber diameter 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.

[0038] Furthermore, in order to obtain a good wearing comfort and sufficient adhesion, it is particularly preferable for the above-mentioned polyurethane elastic nonwoven fabric to have the following properties (1) to (4). (1) Weight: 60-120g / m 2 , especially 80~120g / m 2 , and even 90-110g / m 2 (2) Tensile strength in both the machine direction (MD) and cross direction (CD): 1000cN / 20mm or more In particular, the longitudinal tensile strength is 1200cN / 20mm or more, or even 1600cN / 20mm or more. In particular, the tensile strength in the transverse direction (CD direction) is 1600cN / 20mm or more, or even 1800cN / 20mm or more. (3) Tensile elongation in both the longitudinal and transverse directions: 300% or more, especially 350-520% (4) 100% elongation recovery rate in both the vertical and horizontal directions: 90% or more in both directions, especially 94-100%

[0039] 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" is a value measured in accordance with JIS L1096:2010 8.16.2.

[0040] 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 coolness felt when touched, and the higher the value, the stronger the coolness felt, which is preferable. (5) Air permeability: 50cc / cm 2 / sec or more (6) Maximum heat absorption rate (Q-max): 0.08 or more, especially 0.10 or more

[0041] 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.

[0042] The polyurethane elastic nonwoven fabric having 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 separated from the gas flow and stacked on a collecting device such as a moving conveyor net, and are cooled and solidified while being bonded at their contact points. Of course, after being cooled and solidified on the collecting 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 filter function, high stretchability, and flexibility.

[0043] The polyurethane elastic nonwoven fabric may be one that has been given antibacterial or bactericidal properties. The one that has been given antibacterial properties is hygienic as it inhibits the growth of various bacteria. The one that has been given bactericidal properties can prevent the invasion of bacteria from the outside, and therefore can be used for special purposes.

[0044] Furthermore, the polyurethane elastic nonwoven fabric may be made electrically conductive. By making the mask electrically conductive, static electricity does not build up, so that the mask is more hygienic and does not attract dust or dirt.

[0045] 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 disposable. Therefore, it is desirable that the shape of the polyurethane elastic nonwoven fabric after, for example, 10 home washings (in accordance with JIS L1930:2014 C4M method) does not change as much as possible compared to the shape before washing.

[0046] In the above example, when the mask is folded in half along an imaginary center line P that runs vertically down the center of central portion 2, the upper portion A of the fold is an arc-shaped portion that bulges outward, and the lower portion B is linear, and the welded portion 1 is provided on the arc-shaped upper portion A [see Figure 2(b)].

[0047] The degree of freedom of the fabric in the space around the mouth is determined by the arrangement of the arc-shaped upper part 15 and the straight lower part 16, and it is preferable that the arc-shaped upper part 15 passes vertically from the nose to the mouth. It is preferable that the straight lower part 16 reaches from below the mouth to the chin. For this purpose, it is preferable that the ratio (A / B) of the length dimension A of the upper part 15 to the length dimension B of the lower part 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 part 15 and the lower part 16, is located near the center in the vertical direction of the fold.

[0048] As already mentioned, the width dimension d of the welded portion 1 does not need to be as thick as in the past (for example, 2 mm or more) because the reinforcing effect of the rib is not required. In the present invention, the width dimension d is set to 0.1 to 1.5 mm so that this portion does not come off even if the mask is used repeatedly and the three-dimensional shape can be maintained. In particular, it is more preferable to set the above d to 0.5 to 1.2 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 1 is not stiff, excellent wearing comfort and coolness can be obtained, together with the size of the ear engagement openings 4.

[0049] The radius of curvature R3 of the arc-shaped upper part 15 is usually set to 100 to 150 mm, preferably 120 to 135 mm, although this depends on the longitudinal dimension of the welded part 1. That is, by making this part arc-shaped with an appropriate radius of curvature, the fabric is allowed to have some slack from the nose to the mouth, improving the fit and comfort of wearing without a feeling of pressure around the mouth.

[0050] Moreover, the angle θ″ of the linear lower portion 16 with respect to the tangent X of the upper portion 15 at the switching point position O is preferably set to 15 to 40°, more preferably 20 to 30°, since this further reduces the feeling of pressure around the mouth.

[0051] In the above example, the welded portion 1 is provided only on the upper portion 15 in the fold portion, but the welded portion 1 may be provided at least on the arc-shaped upper portion 15. Of course, as shown in Fig. 4(a), the welded portion 1 may also be provided on the linear lower portion 16, so that the welded portion 1 is continuous from the upper end to the lower end of the fold portion. Alternatively, as shown in Fig. 4(b), the welded portion 1a may be provided on the arc-shaped upper portion 15, and the welded portion 1b may be provided only in a predetermined region of the linear lower portion 16 from its lower end upward, with the portion in between remaining as a fold and unwelded.

[0052] In addition, when forming a continuous welded portion 1 from top to bottom as shown in FIG. 4(a), it is not necessary to fold one sheet of nonwoven fabric in half and weld the fold. Two sheets of nonwoven fabric, a pair of left and right sheets, may be overlapped and one edge may be welded.

[0053] In addition, in the present invention, the opening shape of the ear engagement portion 3 is not limited to the above example, but the above example having a specific first opening portion 5, second opening portion 6, and third opening portion 7 has a structure in which the fabric is divided into upper and lower portions and pulled in the left-right direction, which allows for a high degree of freedom for the fabric in the central portion 2 of the mask, and is optimally combined with the configuration of the fold portion of the present invention.

[0054] When applying the opening shape of the above example, the angle θ [see FIG. 2(b)] at the apex corner of the first opening portion 5 is preferably 30 to 80°, more preferably 40 to 70°, and particularly preferably 50 to 65°. That is, if the angle θ is too large, the opening at the cheek portion becomes shallow, and the effect of dividing the pulling force generated from the ear engagement portion 3 toward the central portion 2 of the mask into upper and lower portions to suppress the influence on the central portion 2 becomes small, which is not preferable. Also, if the angle θ is too small, it is necessary to reduce the upper and lower widths of the ear engagement portion 3 or to increase the width of the fabric at the ear engagement portion 3 (the width between the outline edge of the ear engagement portion 3 and the opening edge), which may cause a poor wearing comfort around the ears, which is not preferable.

[0055] Furthermore, in the opening 4 of the ear engagement portion 3, if the apex corner of the first opening portion 5 is not rounded, the fabric in this portion may stretch and become loose or tear after repeated use and washing, so it is desirable to provide a rounded corner. The radius of curvature R1 (see FIG. 3) of the rounded corner is preferably 1 to 10 mm, and more preferably 2 to 5 mm. If the rounded corner is too large, the effect of dividing the tensile force between the top and bottom of the fabric due to the approximately isosceles triangular shape of the first opening portion 5 becomes weak, which is undesirable.

[0056] In the above example, the apex corners of the first opening portion 5 are arranged so as to face each other toward the center line P of the mask. However, in the present invention, the state in which "the apex corners face toward the center of the mask" does not necessarily mean that the apex corners are arranged so as to face perpendicular to the center line P of the mask, as shown in FIG. 5(a). It is intended to include, for example, an arrangement in which the apex corners are arranged slightly downward with respect to the center line P, as shown in FIG. 5(b), or an arrangement in which the apex corners are arranged slightly upward with respect to the center line P, as shown in FIG. 5(c).

[0057] However, Fig. 5(b), (c)The shape of the apex angle shown in FIG. 5(a) is tilted at a large angle for the purpose of explanation, but in reality, if the direction in which the apex angle bisector D in FIG. 5(a) extends is taken as 0°, then in FIGS. 5(b) and 5(c) each of the bisectors D1 and D2 should be tilted at an angle within ±10°, which is preferable in order to prevent sagging in the mask.

[0058] In the state shown in Figure 5(b) or the state shown in Figure 5(c), the first opening portion 5 is not "isosceles triangular" 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 triangular" shape.

[0059] Similarly, the length dimension L1 [see FIG. 2(a)] extending 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 (L1 / L0) of L1 to the total mask length L0 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 (L1 / L0) 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 be poor.

[0060] 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. 6. However, in order to enlarge the opening of the third opening 7 to provide a comfortable fit, particularly a cool feeling, and to avoid discomfort when engaging with the ear, it is preferable to set the central angle θ' to, for example, 120 to 180°. In addition, taking into account the comfort when engaging with the ear, the radius of curvature R2 (return to FIG. 3) of the arcuate part in the partial circle shape is usually preferably 20 to 30 mm, more preferably 23 to 28 mm, depending on the central angle θ'.

[0061] Furthermore, the third opening 7 does not need to be a partial circle of a perfect circle as described above, but may be an ellipse slightly crushed in the vertical direction, an ellipse slightly crushed in the horizontal direction, or a partial circle of an approximation of a circle that is not an ellipse but is different from a perfect circle. In the present invention, these are collectively called "approximately partial circles". That is, in the mask of the present invention, it is important that the opening shape of the third opening 7 is an approximately partial circle shape without corners in order to obtain a comfortable fit and a cool feeling when engaging with the ears.

[0062] In addition, as described above, when the third opening portion 7 is not a partial circle of a perfect circle, the "radius of curvature R2 of the arc portion" refers to the radius of curvature R2 at a position in the arc portion of the third opening portion 7 opposite the apex angle of the first opening portion 5.

[0063] The width W of the ear-hanging portion 3 (shown by the diagonal line T in FIG. 3) 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 hanging 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, so that the mask is less likely to tear or hurt the ear when hanging on the ear due to localized stress concentration. 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, reducing the fit or making the mask more likely to tear. EXAMPLES

[0064] Next, the present invention will be described based on examples and comparative examples, but the present invention is not limited to the following examples.

[0065] 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.

[0066] [Table 1]

[0067] In Table 1 above, "Pollen prevention performance (removal rate)" is a value calculated in accordance with the method specified by the National Mask Industry Association of the Japan Sanitary Materials Industry Association as the "Pollen particle collection (filtration) efficiency test method."

[0068] [Examples 1 to 9, Comparative Examples 1 and 2] Using the nonwoven fabrics A to D, 11 types of masks (Examples 1 to 9, Comparative Examples 1 and 2) having the characteristics shown in Tables 2 to 5 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 overlapping, melt-cutting and welding were performed on the parts to be welded (notch 10 in FIG. 3). In Example 4, as shown in Fig. 4(a), the upper and lower parts are continuous welded parts, and in Example 5, as shown in Fig. 4(b), the upper part is the first welded part, and the lower part up to a length of 20 mm from the bottom is the second welded part. 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 Comparative Example 1, but with the width dimension d of the welded part set to 0.6 mm.

[0069] 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 to 5 below.

[0070] [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 five items of fit to the face, comfort of the ear loop, freedom of movement around the mouth when opening and closing, coolness of the face, and appearance when wearing the mask on a four-point scale: ◎...very good, ○...good, △...average, ×...bad, with the most common evaluation being the evaluation. If the evaluations given by the same number of people were tied, the tied evaluations were reevaluated by all participants.

[0071] [Washability (whether or not the shape is lost)] In accordance with the JIS L1930:2014 C4M method, after 10 home washes, the garments were visually observed for deformation and rated on a 4-point scale: ◎: no deformation at all, ○: almost no deformation, △: some parts have lost their shape upon close inspection, ×: deformation is immediately apparent.

[0072] [Table 2]

[0073] [Table 3]

[0074] [Table 4]

[0075] [Table 5]

[0076] From the above results, it can be seen that all of the example products have a good wearing feeling, a cool feeling, etc., and also look good. Moreover, they 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 product of Comparative Example 1 is narrow, which hurts the ears and does not feel cool. The welded part is noticeable and looks bad. Moreover, it is assumed to be disposable, and the shape around the welded part is easily distorted. In addition, the product of Comparative Example 2 has a narrow welded part, so it looks good, but the fabric sticks to the mouth, and it is found that the wearing comfort is inferior to the product of the embodiment. [Industrial Applicability]

[0077] INDUSTRIAL APPLICABILITY The present invention can be widely used as a reusable mask that has a good appearance with inconspicuous welded parts and also has excellent adhesion and comfort when worn. [Explanation of symbols]

[0078] 1 Welded area 2 Central part 3 Ear engagement part d Width dimension P center line

Claims

1. 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, In the central portion, the mask is folded in half along an imaginary center line P extending vertically through the center, so that the left and right surfaces of the mask overlap each other. When the two pieces are folded together, the upper part of the fold is curved outward, and the lower part is straight down to the bottom edge. a welded portion having a width dimension d of 0.1 to 1.5 mm is provided along at least the arc-shaped fold portion of the fold, and a three-dimensional shape is imparted by the welded portion; A mask characterized in that 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) and cross direction (CD): both 1000 cN / 20 mm or more (3) Tensile elongation in both the longitudinal and transverse directions: 300% or more (4) 100% elongation recovery rate in both the vertical and horizontal directions: 90% or more

2. 2. The mask according to claim 1, wherein the ratio (A / B) of the length dimension A of the arcuate upper portion to the length dimension B of the linear lower portion in the folded portion is 4 / 6 to 6 / 4.

3. The radius of curvature R of the circular arc at the fold 3 The mask according to claim 1 or 2, wherein the width is 100 to 150 mm.

4. Each of the pair of left and right ear engagement portions is provided with an opening for ear engagement, The mask according to any one of claims 1 to 3, wherein the opening has a first opening portion located closest to the center of the mask, which has a substantially isosceles triangular shape with an apex angle facing the center of the mask, a second opening portion extending laterally from the first opening portion has 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 has a substantially partial circular shape.

5. 5. The mask according to claim 4, 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.

6. The mask according to any one of claims 1 to 5, wherein 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

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