WASH-DURABLE AND REUSABLE RESPIRATORY FACE MASK

Abstract

A wash-durable and reusable respiratory face mask for filtering air comprising a face part configured to cover at least the nose and the mouth of a head of a user includes two substantially symmetrical regions, where each region includes a top edge configured to form a trajectory which runs, when the mask is worn by the user, from the bridge of the nose of the head towards an ear of the head. The trajectory includes at least two sections, the first section being configured to cover at least part of the nose when the mask is worn by the user and forming a substantially convex bend, and the second section extending from the first section toward an ear.

Claims

1. A wash-durable and reusable respiratory face mask (100) for filtering air comprising a face part (105) configured to cover at least the nose and the mouth of a head of a user and comprising two substantially symmetrical regions (110a, 110b) and each region (110a, 110b) comprising a top edge (140) configured to form a trajectory (T2) which runs, when the mask (100) is worn by the user, from the bridge of the nose of the head towards an ear of the head, wherein the trajectory (T2) comprises at least two sections (141, 142), the first section (141) being configured to cover at least part of the nose when the mask (100) is worn by the user and forming a substantially convex bend, and the second section (142) extending from the first section (141) towards an ear.

2. The mask (100) of claim 1, wherein the second section (142) forms a substantially concave bend.

3. The mask (100) of claim 1, wherein the acute angle (A1401) between the tangent (K1401) of the first section (141) at the start of the first section (141) and the tangent (K1403) of the second section (142) at the end of the second section (142) is in the range of 20-60°, preferably 30-50°, more preferably 35-45° and most preferably 37-43°.

4. The mask (100) of claim 1, wherein the maximum value of the acute angle (A1402) between the tangent (K1403) of the second section (142) at the end of the second section (142) and the tangent (K140m) of the first section (141) at any point of the first section (141) is in the range of 50-90°, preferably 60-80°, more preferably 65-75° and most preferably 68-72°.

5. The mask (100) of claim 1, wherein the obtuse angle (A1403) between the tangent (K1402) of the second section (142) at the start of the second section (142) and the tangent (K1403) of the second section (142) at the end of the second section (142) is in the range of 110-180°, preferably 130-165°, more preferably 139-155° and most preferably 143-151°.

6. The mask (100) of claim 1, wherein the point (P140m) in which the second section (142) extends from the first section (141) is located on the trajectory (T2) with the greatest perpendicular distance between the point (P140m) and a straight line connecting the start and the end of the trajectory (T2).

7. The mask (100) of claim 1, wherein L1402 is in the range of 0.5-3.5 cm, preferably 1.0-3.0 cm, more preferably 1.5-2.5 cm, even more preferably 1.8-2.2 cm and most preferably 1.9-2.1 cm; and/or L1402 is in the range of 5-40%, preferably 10-35%, more preferably 14-30%, even more preferably 18-26% and most preferably 20-24% of L1401; wherein L1401 is the length of a straight line between the start and the end of the top edge (140) when the mask lies flat and is folded at its mirror plane, and L1402 is the greatest value of a perpendicular distance between a point (P140m) on the trajectory (T2) of the top edge (140) and L1401.

8. The mask (100) of claim 1, wherein the end of the trajectory T2 and/or the end of the top edge (140) is located in a negative-Y-direction of a length L1403 of 0.2-3.0 cm, preferably 0.4-2.0 cm, more preferably 0.5-1.5 cm and most preferably 0.7-1.2 cm, with respect to the point in which the second section (142) extends from the first section (141), wherein the negative-Y-direction is the direction from the start of a front edge (120) to the end of a front edge (120) of the face part (105) wherein the front edge (120) is comprised by the face part (105) and located at the border between the two regions (110a, 110b) and configured to form a trajectory T1 which runs, when the mask (100) is worn by the user, from the bridge of the nose of the head to the chin of the head, substantially at the symmetrical mirror plane (M1) of the face.

9. The mask (100) of claim 1, wherein the mask (100) comprises a front edge (120) located at the border between the two regions (110a, 110b) and configured to form a trajectory (T1) which runs, when the mask (100) is worn by the user, from the bridge of the nose of the head to the chin of the head, substantially at the symmetrical mirror plane (M1) of the face, wherein the front edge (120) comprises a seam (125) configured continuously along said trajectory (T1).

10. The mask (100) of claim 1, wherein the distance of any point on the trajectory (T1) from the symmetrical mirror plane (M1) of the face when the mask is worn by the user is at most 2.5 cm, preferably at most 2.0 cm, more preferably at most 1.5 cm and most preferably at most 1.0 cm.

11. The mask (100) of claim 9, wherein the seam (125) is a single stitch seam (125).

12. The mask (100) of claim 9, wherein, the trajectory (T1) comprises at least two sections (121, 122), each of which forms a substantially straight line, the first section (121) being configured to cover at least part of the nose when the mask (100) is worn by the user and the second section (122) extending from the first section (121) towards the mouth, and the acute angle (A1201) between the substantially straight lines formed by the first (121) and second sections (122) is in the range of 10-30°, preferably 15-25°, more preferably 17-23° and most preferably 18-22°.

13. The mask (100) of claim 12, wherein the trajectory (T1) comprises a third section (123) forming a substantially straight line and extending from the second section (122) towards the chin, and the acute angle (A1202) between the substantially straight lines formed by the second (122) and third sections (123) is in the range of 12-32°, preferably 15-29°, more preferably 18-26° and most preferably 20-24°.

14. The mask (100) of claim 13, wherein the length of the third section (123) is in the range of 0.5-3.5 cm, preferably 1.0-3.0 cm, more preferably 1.5-2.5 cm and most preferably 1.8-2.2 cm.

15. The mask (100) of claim 14, wherein the trajectory (T1) comprises a fourth section (124) extending from the third section (123) to the chin and the acute angle (A1203) between the substantially straight line of the third section (123) and the tangent (K1201) of the fourth section at the start of the fourth section (124) is in the range of 10-50°, preferably 20-40°, more preferably 25-35° and most preferably 27-33°.

16. The mask (100) of claim 15, wherein the acute angle (A1204) between the substantially straight line of the third section (123) and the tangent (K1202) of the fourth section at the end of the fourth section (124) is in the range of 35-90°, preferably 45-85°, more preferably 55-75° and most preferably 62-68°.

17. The mask (100) of claim 15, wherein the fourth section (124) forms a continuous bend such that L6b is in the range of 2.0-12.0%, preferably 4.0-10.0%, more preferably 5.5-8.5%, even more preferably 6.0-8.0% and most preferably 6.5-7.5% of L5b; wherein L5b is the length of a straight line between the start and the end of the fourth section (124) when the mask (100) lies flat and is folded at its mirror plane, and L6b is the greatest value of a perpendicular distance between a point on the fourth section (124) and L5b.

18. The mask (100) of claim 1, wherein one or more hydrophilic agents and/or one or more antimicrobial agents are adhered to the mask; and/or wherein the mask (100) is at least N90/R90/P90-rated, preferably at least N95/R95/P95-rated and most preferably at least N99/R99/P99-rated.

19. The mask (100) of claim 1, wherein the face part (105) comprises at least one, preferably two, three or more layers (111, 112, 113); and/or wherein at least one layer (111, 112) comprises a textile material and wherein at least one layer (113) comprises a particulate filter material.

20. The mask (100) of claim 1, wherein a layer (111, 112) comprising textile of woven fabrics is an outer layer (111) exposed to the outside when the mask (100) is worn by a user; and/or wherein a layer (111, 112) comprising textile from the group consisting of knitted, warp-knitted, and crocheted fabrics preferably knitted fabrics is an inner layer (112) exposed to the face when the mask (100) is worn by a user.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0142] FIG. 1: is a front view of the face mask according to the invention when worn by the user

[0143] FIG. 2a: is a side view (cut A-A of FIG. 1) of the face mask showing different layers of the face mask in one embodiment

[0144] FIG. 2b: is a side view (cut A-A of FIG. 1) of the face mask showing different layers of the face mask in another embodiment

[0145] FIG. 2c: is a front view of the face mask mounted on a user's head and indicating the sealing element covered by the face part

[0146] FIG. 3a: is a side view of the face mask showing various edges, trajectories, and sections

[0147] FIG. 3b: is a side view of the face mask 100 showing various angles and tangents

[0148] FIG. 3c1: is a side view of the face mask showing various lengths and perpendicular distances

[0149] FIG. 3c2: is a side view of a prior art face mask showing the various lengths and perpendicular distances of the prior art face mask

[0150] FIG. 3d1: is a side view of the face mask according to the invention showing various angles and their values

[0151] FIG. 3d2: is a side view of a prior art face mask showing various angles and their values of the prior art face mask

[0152] FIG. 3e: is a side view of the face mask according to the invention showing details of the top edge of the face mask

[0153] FIG. 4a: is a side view of the face mask worn by the user and showing the distance to the mouth and the fixing tapes

[0154] FIG. 4b: is a side view of a prior art face worn by the user and showing the distance to the mouth and the fixing tapes

[0155] FIG. 5: is a side view of the face mask according to the invention worn by the user and showing the fixing tapes, the binding tapes and the nose clip.

[0156] Throughout the present drawings and specification, the same reference numerals refer to the same elements. The drawings may not be to scale, and the relative size, and depiction of elements in the drawings may be exaggerated for clarity, illustration, and convenience. However, the relative proportions of each drawing may reflect the real proportions unless otherwise stated.

Definitions

[0157] Unless otherwise stated, the term “substantial” or “substantially” as used in the present context may be understood to a great or significant extent or for the most part or essentially.

[0158] In the context of the present invention, “antimicrobial” relates to the ability to kill at least some types of microorganisms, or to inhibit the growth or reproduction of at least some types of microorganisms. Said term relates to any compound, agent, product or process that is harmful to one or more microorganism as used in the context of the present invention. Preferably, the one or more microorganisms get destroyed or inactivated by the “antimicrobial” product or process. By “antimicrobial agent” is meant any substance or combination of substances that kills, inactivates or prevents the growth of a microorganism. The terms “microorganism” and “microbe”, which are used interchangeably in the context of the present invention, are defined to comprise any organism too small to be seen by the unaided eye, such as, especially, single-celled organisms or viruses.

[0159] In the context of the present invention, the terms “textile” and “textile material” relate to a flexible material consisting of fibers, or a network of natural and/or artificial/synthetic fibers, such as a yarn or a fabric. The material may be in its natural or processed or even finished form.

[0160] “Tangents” are defined as a straight line that touches a curve at a point, for instance a section of an edge, an edge or a trajectory, but does not cross that curve at that point. Tangents at a certain point or location on a curve used herein are to be understood to have substantially the same form when the point is varied along the curve by +/−0.1 cm. This should help to avoid misinterpretations of tangents due to local shape deformations of the mask within the context of the present invention. These misinterpretations may arise if the tangent was applied in a mathematical sense, which would reflect even the slightest manufacturing inaccuracies, which is not intended to be applicable herein. A tangent at an end of a section as used herein is to be understood to be located away from the end of the section by 0.05-0.5 cm.

[0161] The term “convex” as used in the present invention is to be understood as having an outline or surface curved like the exterior of a circle or sphere. Also, in terms of a convex polygon for instance, is to be understood as not having any interior angles greater than 180°.

[0162] The term “concave” as used in the present invention is to be understood as having an outline or surface curved inwards like the interior of a circle or sphere. Also, in terms of a concave polygon for instance, is to be understood as having at least one internal angle that is greater than 180 degrees.

[0163] A “bartack” or “bartack seam” is a condensed zigzag seam used for reinforcement or anchoring of textile or fabrics. A “backtack” or backtack seam” is a straight single-needle seam (or actually just 3-4 stitches), that prevents the main seam from unravelling. For instance, the manufacturer backs up a few stitches once the main seam is complete.

[0164] “Particulate filtering material” or “particulate filter material” trap particles, such as dust or aerosols and other droplets which may carry microorganisms, out of the breathing air. Particulate filtering materials may be tested and classified according to their filter efficiency towards the smallest sized particle. Ninety-five percent filtration of particles is the minimum level that is stipulated by the National Institute for Occupational Safety and Health (NIOSH) in the United States for a “95-rating”, according to NIOSH-42CFR84. The particulate filtering materials are further classified according to their oil resistance. In this regard, “N” indicates no oil resistance, “R” indicates slight oil resistance, and “P” indicates strong oil resistance (for example: a N95-rated, R95-rated or P95-rated particulate filtering material).

[0165] When the user stands upright and has their head directed straight to the front, the “vertical height” is measured from the ground in a line extending vertical from the ground, the vertical line forming a perpendicular angle to the ground. The “vertical direction” is directed from the ground upwards, wherein the direction is perpendicular to the ground.

Angle Definitions

[0166] A1201: An acute angle between the substantially straight lines formed by the first 121 and second sections 122 of the trajectory T1 of the front edge 120 as discussed below. [0167] A1202: An acute angle between the substantially straight lines formed by the second 122 and third sections 123 of the trajectory T1 of the front edge 120 as discussed below. [0168] A1203: An acute angle between the substantially straight line of the third section 123 and the tangent (K1201) of the fourth section at the start of the fourth section 124 of the trajectory T1 of the front edge 120 as discussed below. [0169] A1204: An acute angle between the substantially straight line of the third section 123 and the tangent (K1202) of the fourth section at the end of the fourth section 124 of the trajectory T1 of the front edge 120 as discussed below. [0170] A1401: An acute angle between the tangent (K1401) of the first section 141 at the start of the first section 141 and the tangent (K1403) of the second section 142 at the end of the second section 142 of the trajectory T2 as discussed below. [0171] A1402: An acute angle between the tangent (K1403) of the second section 142 at the end of the second section 142 and the tangent (K140m) of the first section 141 at any point of the first section 141 of the trajectory T2 as discussed below. [0172] A1403: An obtuse angle between the tangent (K1402) of the second section 142 at the start of the second section 142 and the tangent (K1403) of the second section 142 at the end of the second section 142 of the trajectory T2 as discussed below. [0173] A1501: An obtuse angle between the tangent (K1501) of the trajectory (T3) at the start of the trajectory (T3) and the tangent (K1502) of the trajectory (T3) at the end of the trajectory (T3) as discussed below. [0174] A150m: An obtuse angle (A150m) between the tangent (K150m) of the trajectory (T3) at the midpoint of the trajectory (T3) and the tangent (K1501) of the trajectory (T3) at the start of the trajectory (T3) as discussed below. [0175] A1601: An angle facing the face part (105) and formed between the tangent (K1502) of the trajectory T3 of the bottom edge 150 at the end of the trajectory T3 of the bottom edge 150 and the tangent (K1601) of the trajectory T4 of the rear edge 160 at the start of the trajectory T4 of the rear edge 160 as discussed below. [0176] A1602: An angle facing the face part 105 and formed between the tangent (K1403) of the trajectory T2 of the top edge 140 at the end of the trajectory T2 of the top edge 140 and the tangent (K1602) of the trajectory T4 of the rear edge 160 at the end of the trajectory T4 of the rear edge 160 as discussed below.

Length Definitions

[0177] L1: Is the smallest distance between the mouth section 128 and the foremost contact point of the lips of the closed mouth when the mask is worn by the user as discussed below. [0178] L2a: Is the length of a straight line between the start and the end of the trajectory (T1) when the mask is worn by the user as discussed below. [0179] L2b: Is the length of a straight line between the start and the end of the front edge 120 when the mask lies flat and is folded at its mirror plane as discussed below. [0180] L3: Is the greatest value of a perpendicular distance between a point on the trajectory (T1) of the front edge 120 and L2b when the mask 100 lies flat and is folded at its mirror plane as discussed below. [0181] L5b: Is the length of a straight line between the start and the end of the fourth section 124 when the mask 100 lies flat and is folded at its mirror plane as discussed below. [0182] L6b: is the greatest value of a perpendicular distance between a point on the fourth section 124 and L5b when the mask 100 lies flat and is folded at its mirror plane as discussed below. [0183] L7b: Is the length of a straight line between the start and the end of the trajectory T4 of the rear edge 160 when the mask lies flat and is folded at its mirror plane as discussed below. [0184] L8b: Is the greatest value of a perpendicular distance between a point on the trajectory T4 of the rear edge 160 and L7b when the mask 100 lies flat and is folded at its mirror plane as discussed below. [0185] L1401: Is the length of a straight line between the start and the end of the top edge 140 when the mask lies flat and is folded at its mirror plane as discussed below. [0186] L1402: Is the greatest perpendicular distance between a point (P140m) on the trajectory (T2) of the top edge 140 and L1401 when the mask 100 lies flat and is folded at its mirror plane as discussed below. [0187] L1403: Is the distance between a point (P140m) on the trajectory (T2) of the top edge 140 and the trajectory T2 and/or the end of the top edge 140 measured in the negative-Y-direction, wherein the negative-Y-direction is the direction from the start of the front edge 120 to the end of the front edge 120 of the face part 105 when the mask 100 lies flat and is folded at its mirror plane as discussed below.

Miscellaneous Definitions

[0188] T1: Trajectory formed by front edge [0189] T2: Trajectory formed by top edge of symmetrical region 110a [0190] T3: Trajectory formed by bottom edge of symmetrical region 110a [0191] T4: Trajectory formed by rear edge of symmetrical region 110a [0192] M1: Symmetrical mirror plane of the face [0193] P140m: Point in which the second section 142 extends from the first section 141, located on the trajectory (T2) with the greatest perpendicular distance between the point (P140m) and a straight line connecting the start and the end of the trajectory (T2).

DETAILED DESCRIPTION

[0194] In the following, exemplary embodiments of the present invention are described in more detail. However, the present invention is not limited to these, and a multitude of other embodiments are applicable without departing from the spirit of the invention.

1. Front Edge with a Continuous Seam

[0195] FIG. 1 shows a front view of a user wearing a wash-durable and reusable respiratory face mask 100 according to an exemplary embodiment of the invention. The face mask 100 comprises a face part 105 that is configured to cover at least the nose and the mouth of a head of a user, and further comprises two substantially symmetrical regions 110a, 110b. The mirror plane M1 of the face of the user serves to define the symmetrical regions 110a, 110b and may thus be used to virtually split the face part 105 into its two symmetrical regions 110a, 110b. At the border of these symmetrical regions 110a, 110b, a front edge 120 is located, which forms a trajectory T1 which runs, when the mask 100 is worn by the user, from the bridge of the nose of the head to the chin of the head (see also FIG. 3, which is a side view of FIG. 1 when the mask lies flat and is folded at its mirror plane). The front edge 120 comprises a seam 125 which runs continuously along the trajectory T1. The seam 125 can be used to attach at least two parts of the face part 105 but may also be present without the technical functionality of connecting two parts of the face part 105. However, the seam 125 typically joins two or more layers of fabric, or other materials and to hold those together with stitches. When the mask 100 is worn by a user, slight deviations of the trajectory T1 and the symmetrical mirror plane M1 of the face of the user may occur. This can happen for instance when the user or another person pulls on one region 110a, 110b or any kind of force acts on the mask 100 or the face part 105 in a way that does not match the normal usage mode of the face mask 100. Therefore, the distance of a point on the trajectory T1 to the symmetrical mirror plane M1 of the face of the user may be at most 2.5 cm, preferably at most 2.0 cm, more preferably at most 1.5 cm and most preferably at most 1.0 cm, without deviating from the exemplary embodiment of the underlying invention. The seam 125 is preferably a single stitch, single ply constructed or double-stitched seam 125. However, any kind of seam may be applied, which includes at least all of the seam types according to the seam type classification and terminology standard ISO 4916:1991, which is hereby incorporated by reference. The manufacturing process is simplified and/or facilitated by using a single stitch seam. If the two pieces of a face part are stitched together, as it is the case in an embodiment of the present invention, they have the appearance of a butterfly. Thus, this type of stitching is also called single needle butterfly stitch. The continuous seam provides smoothness of the front edge and substantially prevents or limits the establishment or occurrence of sharp corners on the front edge, which may be present in the prior art due to seams that are not continuous and therefore have endings on the front edge. More importantly even, this configuration of the seam 125 of the front edge 120 of the mask 100 contributes to stabilizing the pocket which is formed by the face part in front of the mouth of the user. Thus, a desired distance between the face mask 100 or the face part 105 and the mouth of the user is better maintained and in particular capable of withstanding forces exerted on it during an intake of breath by the user.

[0196] With reference to FIGS. 2a and 3a, in a preferred embodiment, the mask 100 comprises three layers 111, 112, 113. The inner layer 112 comprises fabrics of knitted cotton textile, the outer layer 111 comprises fabrics of woven cotton textile, and the third layer 113 comprises particulate filter material, e.g., non-woven fabrics or melt blown fleece. As can be seen in FIG. 2a, the third layer 113 is sandwiched by the inner layer 112 and the outer layer 111. The particulate filter material of the third layer 113 effectively filters the inhaled and exhaled air and the antimicrobial agents that are adhered to the textile material of the remaining layers sanitize the air, e.g., kill microorganisms and viruses.

2. Face Part Layers Divided into Two Pieces

[0197] FIG. 1 also shows that the face mask 100 comprises an outer layer 111 according to an embodiment of the invention, wherein the outer layer in is divided into two pieces along the border of the symmetrical regions 110a, 110b, and thereby also along the symmetrical mirror plane M1 of the face. The outer layer in is exposed to the environment when the mask 100 is worn by the user. FIG. 2 shows the outer layer 111 in an exemplary side view A-A of FIG. 1. The two pieces are separated from and connected to each other. The connection means is in one embodiment achieved by the seam 125 that goes along the trajectory T1, which runs, when the mask 100 is worn by the user, from the bridge of the nose of the head to the chin of the head. The trajectory T1 is formed by the front edge 120.

[0198] Furthermore, the face part 105 comprises a second, inner layer 112 according to an embodiment of the invention, wherein the inner layer 112 is divided into two pieces along the border of the symmetrical regions 110a, 110b, and thereby also along the symmetrical mirror plane M1 of the face. The two pieces are separated from and connected to each other. The connection means is a seam, which is but one example suitable for the use in an embodiment of the invention. FIG. 1 and FIG. 2a also show in an exemplary embodiment that the outer layer 111 comprises a sealing element 106 overlapping the border of the regions 110a, 110b. In addition, or instead, the sealing element 106 may be comprised by the inner layer 112 according to the exemplary embodiment of FIG. 2b. FIG. 2c shows both embodiments in a front view. The sealing element 106 of this exemplary embodiment is glued to the outer layer 111. However, different attachment means are possible. The sealing element 106 has a thickness in the range of 0.05-1.0 mm, preferably 0.08-0.6 mm, more preferably 0.1-0.4 mm and most preferably 0.12-0.2 mm. Depending on the material/parts used for the sealing element the thickness may vary. For instance, if silicon is applied as a material, the thickness may be greater than 1.0 mm. The sealing element 106 is a thin element, comparable to a foil or tape which sticks to the layer, wherein the width and length dimensions are much larger than its thickness. The width of the sealing element 106 is in the range of 0.4-4.0 cm, preferably 0.6-3.5 cm, more preferably 0.8-3.0 cm and most preferably 1.0-2.5 cm, and the length is preferably such that it can cover the complete continuous seam 125 which connects the two pieces of the outer layer together. The thickness of the sealing element 106 is in the range of 0.05-1.0 mm, preferably 0.08-0.6 mm, more preferably 0.1-0.4 mm and most preferably 0.12-0.2 mm. The sealing element 106 comprises or consists of one or more selected materials/parts from the group consisting of seam sealing tape, Silicon, liquid stripe and Polyurethan, preferably the sealing element 106 is a seam sealing tape. The sealing element 106 is flexible and durable, and even though it is lightweight, it is preferably waterproof and seals tightly, which guarantees that no dirt, water, or other elements will leak through and interfere with the bond or seam, which is covered by it. Furthermore, in an exemplary embodiment of the invention, the sealing element 106 fulfills the adhesion tape test according to DIN EN ISO 10683 and water resistance tests similar to DIN 18542, DIN EN ISO 2812-1, DIN EN ISO 2812-1 or DIN EN ISO 16925. Due to these advantageous characteristics, the sealing element 106 is non-permeable for liquids, aerosols and/or air. The permeability to liquids, aerosols and/or air is substantially lower than that of layers 111, 112 of the face part 105. It therefore seals the border of the regions 110a, 110b. This increases safety for the user and the surrounding users because leakage of air without being filtered by the mask 100 is prevented.

[0199] FIG. 2 also shows a third layer 113, which in the exemplary embodiment of the invention is sandwiched by the inner layer 112 and the outer layer in of the face part 105. The third layer 113 is preferably a single-piece and/or non-woven fabric that extends in both regions 110a, 110b. Thus, there is no seam at the border of the two regions 110a, 110b of the third layer 113, and it is therefore best suited for filtering air which enters and exists the mask, for instance by inhaling and exhaling of the user.

[0200] With the arrangement of the layers of the previously described embodiment, the third layer 113 is protected by the outer layer 111 and the inner layer 112. This is in particular beneficial for the washability, durability and reusability of the mask 100, since the non-woven material of the third layer 113, which is suited for filtering the air, is protected against external mechanical, chemical or any other kind of damage during the washing procedure.

3. Front Edge

[0201] FIGS. 1 and 3 show the shape of the front edge 120 of the face mask 100 in a front and a side view, respectively, in a preferred embodiment of the invention. The shape of the front edge 120 is designed to overcome at least part of the limitations of prior art addressed above. It improves the fit of the mask 100 when the mask 100 is worn by a user and provides for a better alignment with the general silhouette of a human's face. The front edge 120 forms a trajectory T1, which runs, when the mask 100 is worn by the user, from the bridge of the nose of the head to the chin of the head, substantially at the symmetrical mirror plane (M1) of the face. The shape is described by different sections. In the embodiment of FIG. 3, four sections are shown. However, the invention is not limited to this configuration, and other embodiments may comprise at least two sections. The first section 121 forms a straight line and covers at least part of the nose, when the mask 100 is worn by a user. The second section 122 is a straight line as well, starts at the end of the first section and extends from it in an angle A1201 of preferably 200 (see angle definition above). The angles of a preferred embodiment are further summarized in Table 4 below in comparison to the prior art. The transition point from the first section 121 to the second section 122 is substantially at the middle of the nose, see FIG. 4. The third section 123 of the trajectory T1 is a substantially straight line as well and extends from the second section 122 in an angle A1202 of preferably 22° (see angle definition above). The length of this third section is typically 2 cm. The start of the third section is in the domain of the trajectory T1 in front of the mouth, typically at the vertical height (for “vertical height”, see definition above) of the upper lip, see FIG. 4. The fourth section 124 of the trajectory T1 is a line that is not straight but has a continuous convex bend or is curved and extends from the third section 123 in an angle A1203 (see angle definition above) of preferably 30°. The length of this third section is typically about 2 cm. The start of the third section 123, and thus the end of the third section 123, is in the domain of the trajectory T1 in front of the mouth, typically at a vertical height (for “vertical height”, see definition above) below the lower lip of the user, see FIG. 4. The angle A1204 (see angle definition above) at the end of the fourth section 124 is preferably 65°. The bend of the fourth section 124 is in a further embodiment specified by using length L5b and L6b (see length definition above). L6b is preferably in the range of 7% of L5b (see Table 1).

TABLE-US-00001 TABLE 1 Lengths of fourth section 124 of front edge 120 Parameter Present application Prior art L5b (non-dimensional) 6.31 5.57 L6b (non-dimensional) 0.44 0.57 L6b/L5b 7.0% 10.3%

[0202] The convex bend of the fourth section 124 in this embodiment supports the alignment of the mask 100 or the face part 105 with the chin of a user and thus improves the prior art masks. The benefit of this arrangement is that the tangent at the end of the fourth section 124 of the trajectory T1 formed by the front edge 120 matches the curvature of the chin of the user. Furthermore, the overall shape of the front edge takes into account a reduction of fabric remnants and thereby improves manufacturing. Any angle variation that occurs on the sections (121-124) of the trajectory T1 or on the trajectory T1 formed by the front edge 120 along the path of the trajectory T1 is limited to a maximum value, e.g. at most 28-32°, on a minimum pathlength, e.g. at least 0.5-0.8 cm. In such an embodiment of the present invention, the visual acceptance and attraction to the face mask is increased as opposed to a mask that has sharp angle variations and thus sharp corners in the front edge.

4. Distance to the Mouth

[0203] FIGS. 4a and 4b show the distance L1 from the mouth section 128 of the front edge 120 to the lips of the user in one embodiment of the invention when the mask is worn by the user. FIGS. 3c1 and 3c2 show the distance L3 of the front edge 120 of the face mask 100 from the straight line L2b in one embodiment of the invention when the mask lies flat and is folded at its mirror plane. The mask 100 of these embodiments maintains a certain distance L1 or L3 (see length definition above) shown in Table 2 below. The drawings as well as the Table show the difference over a prior art mask.

TABLE-US-00002 TABLE 2 Distances of mouth section 128 of front edge 120 to mouth of a user, for the definition of the lengths see above Parameter Present application Prior art mask L1 4.5 cm 2.7 cm L1/L2a 29% 19% L3 4.9 cm 4.1 cm L3/L2b 32% 29%

[0204] The configurations of this embodiment have the advantage that the material of the mask 100, for instance the textile material, is prevented from getting in touch with the mouth when the user inhales or otherwise changes the facial expression, due to the increased distance from the front edge to the mouth. This is beneficial for speaking and any other activity performed with the mouth and provides the user with more comfort, because the mask touching the mouth is unpleasant.

5. Top Edge

[0205] FIG. 1 depicts the top edge 140 of the face part 105 of the mask 100 along with the trajectory T2 that it forms in a front view. FIG. 3 illustrates the same edge in a side view. The trajectory T2 has two sections according to an embodiment of the present invention. However, the invention is not limited to two sections. Multiple sections can be defined along the trajectory, as the skilled person is aware of several strategies to identify sections on any trajectory. The trajectory T2 runs, when the mask 100 is worn by the user, from the nose of the head towards an ear of the head. The first section 141 covers at least part of the nose when the mask (100) is worn by the user and forms a substantially convex bend. The second section 142 extends from the first section and forms a concave bend. The convex bend has an angle A1401 (see angle definition above) at the start of the first section 141 of 400 and a maximum angle of 70° along the path of the trajectory T2, see FIG. 3d1. The angles of a preferred embodiment are summarized in Table 4 below in comparison to the prior art. The bend of the second section 142 is less pronounced than the one of the first section 141. The transition point from the first to the second section is located where the convex bend changes into a concave bend. This point is further specified as P140m in one embodiment in FIG. 3e and described as the point P140m located on the trajectory T2 with the greatest perpendicular distance L1402 between the point P140m and a straight line L1401 connecting the start and the end of the trajectory T2. In this embodiment, L1402 has a length of 2 cm, which represents 22% of the length L1401, see Table 3.

[0206] The shape of the top edge 140, by virtue of the present embodiment, provides a tight and smooth fit and seal around the region of the nose and the eyes and ensures that the mask covers the relevant portions of the face to prevent inhaling or exhaling of unfiltered air. The region of the nose and the eyes of a face of a user is dominated by 3D shape variations of the surface of the user's face, in particular in the direction of the trajectory T2. A good seal between the mask and the face is therefore a major challenge. The convex-concave shape of the top edge 120 is well suited to cope with this challenge and supports a flush sealing. The convex shape of the first section 141 in combination with the starting location of the first section 141 at the bridge of the nose ensures that the top edge 140 of the mask 100 covers a region of a face that has less pronounced 3D shape variations. In contrast, if the first section was a straight line, it would not allow to follow the 3D shape variations of the surface of the face and would thus not create a tight sealing. Also, if the top edge started at a nose portion at a vertical height (for “vertical height”, see definition above) lower than the bridge of the nose (e.g., as shown for the prior art mask in FIG. 4b), the 3D shape variations of the surface of the user's face would be more pronounced in the direction of the trajectory T2, and sealing could be accomplished as well. Thus, a further benefit of the embodiment described above is that the top edge starts at the bridge of the nose, in particular at an upper portion of the nose, rather than for instance closer to the tip of the nose. Due to the concave shape of the second section of the top edge 140, a cutout or cutout pocket for the eyes is established. This has the effect that the mask maps the curvature of the user's face better while providing for a good seal. In the prior art mask, glasses or spectacles that a user potentially wears may become steamed up or fogged due to air leaking through at least some of the regions of the face of pronounced 3D shape variations close to the side of the nose. The pronounced convex-concave shape of the top edge 140 has the further advantage to better fit and better model a 3D geometry like a human's face by a 3D mask 100 or face part 105, which is manufactured out of a flat 2D textile and therefore incorporates substantial improvements for the production of this mask. The shape of the top edge 120 has the further advantage that glass wearers do not have to cope with steamy glasses due to the fact that the top edge starts at the bridge of the nose and the natural position of the glasses is at a position of the nose that is closer to the nose tip than the start of the top edge, see FIG. 4a, compared to prior art FIG. 4b. Thereby, the glasses sit on top of the mask, even further providing a tight sealing due to mechanical forces acting on the mask towards the face of the user. In particular, this embodiment of the present invention also ensures that the glasses or spectacles worn by a user substantially do not become steamed up or fogged as compared to the prior art mask described above. This beneficial effect would even be achieved, if the glasses were not sitting on top of the mask, but on the skin, for instance at the bridge of the nose. This is, because the shape of the mask in this embodiment substantially prevents air from leaking at least through the regions close to the eyes and the nose and thereby preventing potentially warm and exhaled air by the user from getting in contact with the glasses. This effect may also be reasoned by the combination of a multitude of the individual features of the mask according to this embodiment.

TABLE-US-00003 TABLE 3 Lengths of the top edge 140; for the definition of the lengths see above Parameter Present application Prior art L1402 2 cm 0.4 cm L1402/L1401 22% 0.5%

[0207] The embodiment of the top edge in FIG. 3e has a distance or length L1403 of 0.9 cm from the end of the trajectory T2, which represents the end of the top edge 140. This distance is measured in the negative-Y-direction, which is defined in the embodiment in FIG. 3e as the direction from the start of the front edge 120 to the end of the front edge 120 of the face part 105. However, other distances or lengths L1403 are possible without contravening the scope of the present invention.

6. Bottom Edge

[0208] FIG. 1 shows the bottom edge 150 of the face part 105 of the mask 100 in one embodiment of the invention. FIGS. 3a-3d2 give further details of one embodiment of the bottom edge 150, also in comparison to a prior art mask. The comparison of the angles of the bottom edge 150 is shown in FIGS. 3d1 (present embodiment) and 3d2 (prior art mask). The difference in the angles is appreciated by the user, since it provides a better fit, especially in the region of the chin towards the jawbone. This is especially apparent when comparing FIGS. 4a (present embodiment) and 4b (prior art mask). In this embodiment, the cheek region of the face is covered by the mask to a greater extent. Therefore, a better sealing can be established, because the region of the cheek closer to the mouth is subject to higher and more frequent shape variations when the user speaks or changes certain facial expressions.

[0209] The angles of a preferred embodiment are further summarized in Table 4 below in comparison to the prior art.

7. Pre-Stretched Edge

[0210] FIG. 5 shows the longish and elastic binding tape 180 in an embodiment of the present invention that is comprised by the bottom edge 150 of the face mask 100. However, other edges of the mask may also comprise a longish and elastic binding tape 180, in particular the top edge 140 (not shown). To ensure a tight seal and at the same time a comfortable feeling for the user, the bottom edge 150 is manufactured in the following way: the binding tape 180 is elongated by 10% in the longitudinal direction, however, different amounts may also be applicable within the scope of the present invention. Then the binding tape 180 is attached to the bottom edge 150 with a seam. This pre-stretching of the binding tape 180 ensures that when the mask is worn by a user, a natural look of the material without the appearance of a large number of folds is established. That is because in use mode, an expansion of the binding tape 180 of the bottom edge 150 occurs which brings the material of the face part 105 back in is original shape and position. Furthermore, the pre-stretching ensures that the edge streamlines well with the shape of the user's face, in particular with the shape of the chin. Thereby the pre-stretching supports a flush sealing. In particular, a good balance of a pre-stretching that is not too strong and not too loose is established. In this arrangement, the pleasant feeling of the mask also supports easy breathing for the user even during prolonged use.

8. Rear Edge

[0211] FIG. 1 shows an embodiment of the rear edge 160 of the face part 105 of the face mask 100. FIGS. 3a-3d2 show further details and a comparison to a prior art mask. The comparison of the angles of the rear edge 160 is shown in FIGS. 3d1 (present embodiment) and 3d2 (prior art mask). The difference in the angles provides a better fit to the user's face. Table 4 below lists the differences between the angles of an embodiment of the present invention and the prior art. The angle A1601 has a value of 109° and is sufficiently smaller than the corresponding angle of prior art mask. This also supports a more structured and clean appearance of the mask, which is appreciated by the user. The angles of a preferred embodiment are further summarized in Table 4 below in comparison to the prior art.

9. Overlapping Fixing Tape

[0212] FIG. 5 shows an embodiment of the longish and preferably elastic fixing tapes 170 of the face mask 100. Two fixing tapes 180 overlap with the mask 100. The fixing tapes 170 fix the mask 100 to the user's head. For that purpose, the fixing tapes 170 may go around the back side of the head when the mask 100 is worn by the user. FIG. 4a shows this in a preferred embodiment, and for the sake of comparison, FIG. 4b shows the fixing tapes of a prior art mask. The fixing around the head provides for a pleasant feeling even during prolonged use as compared to the prior art mask, in which the fixing means leads to a painful feeling around the ears when the mask 100 is worn for a longer period of time. Advantageously, even for glasses/spectacle wearers there is enough space between the mask and the face/glasses when the mask is about to be mounted into the final position on the head by the user. This is beneficial so that the glasses do not slip out of place.

[0213] The fixing tape 170 overlaps with the face part 105 in the longitudinal direction of the fixing tape 170 by a length L4 of 1 cm. The overlapping length is fixed to the face part 105 with two seams. One seam runs in the longitudinal direction of the overlapping length of the fixing tape 170 and is positioned at a vertically lower end of the fixing tape 170. The other seam runs in the direction perpendicular to that and is positioned close to the ending of the face part 105. The latter seam is a bartack stitch seam with a backtack stitch to prevent unravelling of the seam. This supports a firm fit and ensures mechanical integrity, well suited for prolonged use. In comparison to the prior art mask, the overlapping length is increased to improve the structural and mechanical integrity.

10. Enclosed Fixing Tape

[0214] Furthermore, FIG. 5 shows an embodiment of two longish and preferably elastic fixing tapes 170 of the face mask 100, wherein the overlapping lengths L4 of the fixing tapes 170 are enclosed by two longish and elastic binding tapes 180. The two binding tapes 180 are folded in half and enclose the upper and the lower edge of a plane panel 115 (also shown in the embodiment of FIG. 2c) of the face part 105. This enclosure also ensures that the overlapping lengths L4 of the fixing tapes 170 are enclosed and not exposed to the outside. Thus, they are protected from external impacts, which is beneficial for prolonged use. Furthermore, the binding tapes 180 are connected to the plane panel 115 by a seam. Part of this seam is the same as the one that attaches the fixing tape 170 in the longitudinal direction to the face part 105. With this arrangement, the number of seams is reduced and the manufacturing of the mask 100 is facilitated while the mechanical integrity is secured.

11. Further Aspects

[0215] FIG. 5 shows an exemplary embodiment of the face mask 100 with a nose clip 107 positioned at a mirror plane of the face of the head. The nose clip 107 extends to both sides of the mask and is enclosed by the binding tape 180. Thereby, the nose clip 107 is located close to the top edge 140 of the mask. The binding tape 180 is folded in half and connected to the face part 105 with a longitudinal seam, located substantially in parallel to the top edge 140 in a distance of about 0.5-0.7 mm. The nose clip 107 is fixed to the binding tape 180 so that relative movement with respect to the binding tape 180 is prevented. Thus, it is ensured that it is located at its preferred symmetrical position where it supports the shape of the mask 100 and the top edge 140 the most. It comprises material that supports maintaining a predefined shape. The user can manually adjust the nose clip 107 according to his own needs, e.g. so that it best fits to his individual nose.

[0216] Table 4 below lists the differences of the angles of a preferred embodiment according to FIG. 3d1 and the prior art mask according to FIG. 3d2.

TABLE-US-00004 TABLE 4 Comparison of angles of embodiments of the present invention and the prior art mask Angle Present application Prior art A1201 20° 34° A1202 22° 30° A1203 30° A1204 65° A1401 40° 20° A1402 70° A1403 147°  A1501 110°  138°  A150m 136°  A1601 109°  125°  A1602 94° 95°

Test Reports of Examples of Preferred Embodiments

[0217] It will also be appreciated that the masks may be configured to be compliant with a range of international respirator standards, as described in the following. A series of different face masks were tested according to the test protocols stated herein, for instance according to the standards of the National Institute for Occupational Safety and Health (NIOSH). Stringent requirements are prevailing for face masks as the one of the present invention. These requirements are manifested, e.g., in the Code of Federal Regulations (CFR) in title 42 “Public Heath”-under part 84 “Approval of respiratory protective devices”. The following tests comprise the 42 CFR 84.180 (Airflow resistance tests: Inhalation and Exhalation) and the CFR 84.181 (Non-powered air-purifying particulate filter efficiency level determination). A further test for the particulate filter efficiency is provided that is conducted on a TSI 8130 A Machine.

[0218] 1. Inhalation Resistance Test: TEB-APR-STP-007 (42 CFR 84.180)

[0219] The resistance to airflow is measured in the facepiece of the particulate respiratory mask mounted on a test fixture with air flowing at continuous rate of 85±2 liters per minute, before each test conducted in accordance with 42 CFR 84.182. The resistances for particulate respirators upon initial inhalation shall not exceed 35 mm water column height pressure and upon initial exhalation shall not exceed 25 mm water column height pressure. The test results in the Table below confirm that the exemplary masks at least fulfill the N95 standard.

TABLE-US-00005 TABLE 5 Test results for inhalation TEB-APR-STP-007 (42 CFR 84.180) Max. allowable Actual inhalation resistance (mm of resistance (mm Specimen H2O) (NIOSH N95) of H2O) Result 1 35 9.0° Pass 2 35 8.5 Pass 3 35 9.7 Pass

[0220] For FFP2 standard (EN-149-2001) the max. allowable resistance value for inhalation is 24.5 mmH2O (240 Pa) at a flow rate of 95 liters per minute and 7.1 mmH2O (70 Pa) at a flow rate of 30 liters per minute. The tests indicate that all tested masks also fulfill the FFP2 requirement (manifested under the EU Norm EN 149) since there remains sufficient margin to cope with an increasing flow rate from 85 to 95 liters per minute.

[0221] 2. Exhalation Resistance Test: TEB-APR-STP-003 (42 CFR 84.180)

[0222] Same procedure as for the inhalation resistance test applies for the exhalation resistance test in here. The test results in the Table below confirm that the exemplary masks at least fulfill the N95 standard.

TABLE-US-00006 TABLE 6 Test results for exhalation TEB-APR-STP-003 (42 CFR 84.180) Max. allowable Actual inhalation resistance (mm of resistance (mm Specimen H2O) (NIOSH N95) of H2O) Result 1 25 5.8° Pass 2 25 5.3 Pass 3 25 6.1 Pass

[0223] For FFP2 standard (EN-149-2001) the max. allowable resistance value for exhalation is 30.6 mmH2O (300 Pa) at a flow rate of 160 liters per minute. The tests indicate that all tested masks also fulfill the FFP2 requirement (manifested under the EU Norm EN 149) since there remains sufficient margin to cope with an increasing flow rate from 85 to 95 liters per minute.

[0224] 3. Particulate Filter Efficiency Test: TEB-APR-STP-059 (42 CFR 84.181)

[0225] This test is suited for the determination of Particulate Filter Efficiency Level for N95 Series Filters Against Solid Particulates for Non-Powered, Air-Purifying Respirators. This procedure establishes the means for ensuring that the particulate filtering efficiency of N95 series filters used on non-powered respirators submitted for Approval, Extension of Approval, or examined during Certified Product Audits, meets the minimum certification standards set forth in 42 CFR, Part 84, Subpart K, § 84.181. These filters or filter cartridges may be integral to respirator construction; mounted individually, or in sets of up to three; used in conjunction with cartridges and canisters for chin-style, front-mounted, and back-mounted gas masks; or used in combination with gas-and-vapor or atmosphere-supplying respirators.

[0226] The content of the test procedure manifested within TEB-APR-STP-059 and 42 CFR 84.181 shall be considered to be comprised within this specification. The test results in the Table below confirm that the exemplary masks at least fulfill the N95 standard.

TABLE-US-00007 TABLE 7 Test results for particulate filter efficiency test TEB-APR-STP-059 (42 CFR 84.181) Max Flow Initial Filter Allowable Initial Max Filtration Rate Resistance Leakage Leakage Leakage Efficiency Specimen (Lpm) (mmH.sub.2O) (%) (%) (%) (%) Result 1 85.3 10.6 5.00 1.78 4.50 95.50 Pass 2 85.8 10.9 5.00 1.32 3.26 96.74 Pass 3 85.3 11.9 5.00 1.73 3.39 96.61 Pass 4 85.8 11.5 5.00 1.18 4.34 95.66 Pass 5 85.7 12.7 5.00 1.74 3.54 96.46 Pass 6 85.7 12.9 5.00 1.57 2.87 97.13 Pass 7 85.8 11.1 5.00 1.84 4.28 95.72 Pass 8 85.9 14.2 5.00 2.84 4.93 95.07 Pass 9 85.3 62.9 5.00 3.9 3.9 96.09 Pass 10 85.8 21.9 5.00 1.97 4.11 95.89 Pass 11 85.8 12.2 5.00 1.36 3.11 96.89 Pass 12 85.8 12.7 5.00 1.62 3.35 96.65 Pass 13 85.7 67.6 5.00 1.69 2.80 97.20 Pass 14 85.1 64.7 5.00 4.91 4.91 95.09 Pass 15 85.8 12.1 5.00 2.01 4.48 95.52 Pass 16 85.4 61.5 5.00 1.56 2.84 97.16 Pass 17 85.4 61.6 5.00 1.01 2.15 97.85 Pass 18 85.5 64.0 5.00 1.37 2.74 97.26 Pass 19 85.9 11.2 5.00 1.42 3.49 96.51 Pass 20 85.5 60.0 5.00 1.14 2.53 97.47 Pass

[0227] 4. Particulate Filter Efficiency Test on a TSI 8130 A Machine

[0228] A further test regarding the particulate filter material (non-woven fabric) was conducted. The 8130 A machine is suited for test standards for instance according to US-standards 42 CFR 84, Chinese standards GB2626, Japanese standard JMOL and European standard EN 143, ISO 16900-3. The flow rate was 85 Lpm and the measured initial filter efficiency was in the range of 97.5%-99.5%, the loading test minimum efficiency was 95.5%-97.5% and the initial air resistance was 85 Pa. The test results confirmed that the exemplary particulate filter material at least fulfills the N95 and KN95 standard.

LIST OF REFERENCE NUMBERS

[0229] 100: Face mask [0230] 105: Face part [0231] 106: Sealing element [0232] 107: Nose clip [0233] 110a: Symmetrical region [0234] 110b: Symmetrical region [0235] 111: First layer of face mask [0236] 112: Second layer of symmetrical region [0237] 113: Third layer of symmetrical region [0238] 115: Plane panel [0239] 120: Front edge [0240] 121: At least one section, first section of first trajectory [0241] 122: At least another section, second section of first trajectory [0242] 123: Third section of first trajectory [0243] 124: Fourth section of first trajectory [0244] 125: Seam at front edge [0245] 128: Mouth section [0246] 140: Top edge [0247] 141: First section of T2 [0248] 142: Second section of T2 [0249] 150: Bottom edge [0250] 160: Rear edge [0251] 170: Fixing tape [0252] 180: Binding tape