FR3109500A1 - Filtering protective mask - Google Patents

Abstract

Filtering protection mask Respiratory protection mask (1), comprising: a plastic shell (10) to be placed on the face, this shell comprising: a flexible rear part (11) without added seal, having a rear edge (19) adapted to match the shape of the face, the rear part (11) being made with a wall thickness (e) of between 0.15 and 0.5 mm over at least part of its periphery, and a front part provided with a zone for receiving (17) a filter material holding element (30). Figure for abstract: Fig. 1

Description

Filtering protective mask

The present invention relates to a filtering protective mask.

Surgical protective masks are known, consisting of one or more layers of textile held on the face of the user by elastic bands. The disadvantage of these masks is that they are dedicated to single use, and thus generate a significant amount of waste.

In addition, the quality of protection is relatively low, these masks being intended primarily to prevent the wearer of the mask from splashing onto those around them.

Masks with a preformed shell also exist. These masks in principle have an improved filtering power, for example FFP2 or FFP3, but their relative rigidity means that the interface with the skin is often imperfect, especially for certain face morphologies. Passages formed between the skin and the edge of the mask can leak air, which reduces the effectiveness of the mask and can constitute an annoyance for wearers of glasses by directing the hot exhaled air towards them, with a risk of condensation.

To improve the interface with the skin, it is common to add a metal insert to conform to the shape of the nose or a foam gasket. However, these elements complicate the manufacture of the mask and its recycling. In addition, such masks remain disposable.

Faced with the current shortage of masks in some countries due to the COVID -19 epidemic, it has been proposed to make and use washable textile masks. These masks are similar in their filtration qualities to basic surgical masks, and are essentially intended only to protect the user's environment from the risk of projections from the wearer. Their cleaning to be satisfactory requires respecting specific conditions, in particular drying at high temperature or ironing. In addition, they are often thick and therefore relatively heavy and uncomfortable for some. Finally, their manufacture is difficult to automate, because it requires sewing operations.

It has been proposed on some forums to use 3D printers to make plastic masks arranged to receive a filtering material such as a cotton disc and allow its replacement. The masks offered, however, have a shell whose shape substantially reproduces that of existing FFP2 masks, and are relatively heavy and uncomfortable to wear over a long period. In addition, these masks are intended for single printing, and their cost price is incompatible with mass production likely to meet the high demand in times of health crisis. For comfort at the interface with the skin, a silicone seal is added.

There is therefore a need to benefit from a mask which is at the same time comfortable, allows efficient filtration, reusable and easy to clean, even to sterilize and recycle, and capable of being easily produced on a large scale at a cost compatible with wide distribution.

The invention aims to meet this need and it achieves this thanks to a respiratory protection mask, comprising:

• a plastic shell to be placed on the face, this shell comprising:
  • a flexible rear part without added seal, having a rear edge adapted to match the shape of the face, and
  • a front part provided with a zone for receiving an element for holding a filtering material, this front part preferably comprising two lateral bosses which are connected at the front to said reception zone.

Advantageously, the rear part is made with a relatively thin wall thickness, preferably between 0.15 and 0.5 mm, over at least part of its periphery. Also advantageously, the rear ends of the bosses are remote from the rear edge of the shell.

The mask according to the invention has many advantages.

First of all, its shape is compatible with production by 3D printing in batches or by injection molding. The material used for manufacture can be chosen so as to be compatible with going through the dishwasher, or even be sterilizable in an autoclave.

The thin material of the back part provides great flexibility at the interface with the skin, and the back of the shell can be easily deformed to adapt to the shape of the face. This reduces the risk of leaks between the mask and the face, which improves safety and comfort by reducing the risk of hot exhaled air projecting onto the wearer's goggles. The thinness of the material also contributes to the lightness of the mask and the comfort of wearing it. The presence of side bosses in preferred embodiments contributes to stiffening the hull at the front without unduly harming its deformability at the rear. The fact of stiffening the shell at the front makes it easier to fix the holding element and facilitates handling of the mask, which can be done through the nose of the latter to position it correctly on the face, without the user not be penalized by the flexibility of the rear part.

Preferably, the rear part is made with a wall thickness comprised between 0.15 and 0.5 mm all around, better still comprised between 0.15 and 0.4 mm, even better comprised between 0.15 and 0.35 mm , for example 0.25mm.

The shell advantageously has a material thickness, on its rear edge in contact with the skin, of less than 0.3 mm.

The hull can advantageously be produced by 3D printing, in batches, with a personalized shape, if necessary.

In an exemplary implementation of the invention, the element for holding the filtering material comprises a part for fixing to the shell, defining a housing for receiving the filtering material, and a part for retaining the filtering material, configured to fix on the fixing part. The fact of attaching the holding element to the shell can make it possible to produce it separately, and facilitate the manufacture of the shell, in particular by 3D printing, by allowing the shells to be stacked during their production.

The retaining part can be configured to attach to the fixing part in an adjustable manner, being able to be moved relative to the fixing part until the desired tightening for the filter material is obtained.

This can make it possible to immobilize a variable thickness of filtering material, or even several one or more layers of filtering material, at the choice of the user, and according to the desired filtration efficiency. The invention thus offers the possibility of using a large number of different filtering materials, thereby reducing the risk of shortages.

Preferably, the retaining part is mounted in a captive manner, being connected by a hinge to the fixing part.

The housing for receiving the filtering material is preferably of circular outline, adapted to receive a disk of filtering material. Thus, the user can use as filtering material a cotton disc of the type used to remove make-up, which is easy to obtain, or any other suitable substrate.

The hull can be formed at the front with a grid made in one piece with the rest of it. This grid provides a flat receiving surface for the filter material and can help to further stiffen the shell at the front, in the area where the holding element is received.

The element for holding the filtering material can be arranged to be mounted by any means on the shell, for example by screw thread, cone on cone or bayonet-type fixing.

The holding element can be arranged to press the filter material against the shell once mounted. For example, the shell is made with a grid at the front, against which the filter material is pressed by the holding element.

As a variant, the element for holding the filtering material is arranged to be fixed from the inside on the shell. In this particular case, the holding element may be in the form of a ring.

The retaining element can be arranged to be fixed from the outside on the hull.

The element for holding the filtering material can be arranged to be fixed on the shell by pinching or pressing the filtering material against the shell so as to ensure its maintenance.

Preferably, the mask comprises two buttons integral with the shell, for attaching an elastic band, preferably single, these buttons preferably having an oval head, elongated in a direction perpendicular to the direction of traction of the rubber band. This can make it possible to use an elastic band provided with buttonholes, while facilitating the assembly of this band and its maintenance. The presence of buttonholes along the support band allows easy adjustment of the length of the elastic band. The elastic band can be easily removed if necessary to facilitate washing of the mask. The buttons are preferably arranged on the shell so as not to interfere with the stacking of the masks for manufacture, and in particular the buttons can engage in the shell immediately under a given shell of the stack.

The side bosses may have the same thickness of material as the rear part of the shell, at least over the major part of their length.

Preferably, the rear part of the shell ends in a rounded edge directed outwards. The rounding avoids injuring the skin and the outward orientation preserves the flexibility of the back part.

The aft end of the bosses may be moved a distance (d) of at least 15mm from the aft edge of the hull. This distance is measured along the rear part.

The radius of curvature of the side bosses at their top and at mid-length thereof is for example between 20 and 30 mm. Preferably, this radius of curvature tends to increase towards the rear, the bosses preferably having a generally conical shape.

The side bosses preferably have a relief of between 10 and 20°, better still of between 13 and 17°, for example of the order of 15°. Such a value makes it possible to optimize the production of masks by 3D printing, by making it possible to produce a stack of a high number of shells in the same tank while avoiding the risk of fusion of the shells between them. The rear part then has, in particular for such clearance angle values of the side bosses, a clearance greater than that of the side bosses, at least on the sides.

Preferably, the side bosses connect at the front to a thicker neck, at least partially defining the reception area.

The mask, and in particular at least the shell, is preferably made of polyamide 11, optionally incorporating a biocidal agent or to which a biocidal material has been applied, for example in the form of a spray. The material used can be chosen for its compatibility with passage through a dishwasher and/or its sterilization in an autoclave.

Another subject of the invention is a process for manufacturing a mask as defined above, in which the technique for manufacturing the mask is an additive manufacturing technique. In particular, a batch of several stacked masks can thus be produced in the same manufacturing tank.

The additive manufacturing technique also allows customization of the shape of the hull. It is thus possible to generate a file making it possible to control a 3D printer used for the manufacture of the shell, from information on the morphology of the person intended to wear the mask, in particular from an at least partial 3D scan of the face of it.

The invention also relates to a method for manufacturing a mask according to the invention in which the shell is produced by injection molding. In this case, it is advantageous to mold the retaining element with the hull. The latter is for example connected to the shell by a hinge or by one or more breakable bridges of material.

Another subject of the invention is a method for cleaning a mask according to the invention, in which the filtering material and possibly the elastic band are removed, and the mask is washed in a dishwasher. A new filter material can be placed on the clean mask.

The mask can also be made of a material suitable for sterilization in an autoclave, if necessary.

The invention may be better understood on reading the detailed description which follows, non-limiting examples of implementation thereof, and on examining the appended drawing, in which:

FIG. 1 represents in perspective an example of a mask according to the invention,

FIG. 2 is a view similar to FIG. 1 of the mask after opening of the element for holding the filtering material, the latter being represented before insertion into its housing,

FIG. 3 represents the mask before assembly of the retaining element on the hull,

Figure 4 is a section of the hull in a transverse plane,

Figure 5 illustrates the mounting of the elastic band on the shell,

Figure 6 is a partial section along the axis of the housing for receiving the filter material,

FIG. 7 partially and schematically shows in section the rear edge of the hull,

Figure 8 shows a detail of the reception area,

Figure 9 is a side view illustrating the positioning of the fastening buttons of the elastic band,

FIG. 10 is an exploded view of a first mask variant according to the invention,

FIG. 11 is an exploded view of a second mask variant according to the invention,

FIG. 12 is an exploded view of a third mask variant according to the invention,

FIG. 13 represents in perspective a variant of a mask, and

FIG. 14 represents in elevation a stack of mask shells as obtained by additive manufacturing.

detailed description

An example of a mask 1 according to the invention will now be described with reference to FIGS. 1 to 8.

The latter comprises a shell 10 to be applied to the face, carrying a filtering material 30, visible in FIG. 2 in particular, held in place by a holding element 20 attached to the shell 10 in a reception zone 17.

The shell 10 has a flexible rear part 11 of generally flared shape towards the rear, terminated by an edge 19 visible in FIG. 7, rounded and directed outwards.

The top of the shell 10 forms a narrower zone 14, intended to match the shape of the bridge of the nose.

The shell 10 has at the front two bosses 12a and 12b of generally conical shape, flaring towards the rear with a draft of about fifteen degrees with respect to the axis X of the front part. The radius of curvature R of each boss 12a or 12b thus increases towards the rear, being for example of the order of about twenty mm at mid-length of the bosses, when progressing from the front to the rear.

The bosses 12a and 12b are connected to the rear part 11 of the shell along a junction line 70 distant by a distance d from the rear edge 19 of the shell 10, as can be seen in FIG. 8 in particular. This distance d is for example of the order of about twenty mm. The rear part 11 has, in the extension of the bosses 12a and 12b towards the rear, a larger taper, as can be seen in Figure 6.

The bosses 12a and 12b meet at the front at a neck 16 forming a shoulder 72. The neck 16 is terminated by a collar 18 participating in the assembly of the holding element 20.

In the example considered, the neck 16 supports a grid 80 against which the filtering material 30 bears on one side, as can be seen in Figure 6 more particularly.

The flange 18 has a circular outline with flats 83, three in number, arranged at 120° from each other, as can be seen in Figure 3.

The fixing element 20 has, as can also be seen in this figure, a fixing part 21 arranged to be fixed on the neck 16, and a holding part 22, connected by a hinge 23 to the fixing part 21. The latter has a wall defining an opening 84 to be engaged on the neck 16. The opening 84 has a circular outline with flats 24 and immobilization stops 25. The collar 18 is provided on its face facing the rear with corresponding notches 85, intended to cooperate with the stops 25 to block the rotation of the fixing part 21 at the end of its assembly on the neck 16.

The holding part 22 has a grid 28 surrounded by a raised edge 90, itself terminated by a rim 91 directed outwards.

The mask 1 is held on the user's head by an elastic band 40, visible in Figure 5 only, not shown in the other figures.

This strip 40 is provided with at least one buttonhole 41 at each end, and better still with buttonholes 41 distributed over its entire length at regular intervals.

The shell 10 is made with two buttons 13 for attaching the band 40. Each button 13 has a head of oval section, with a major axis oriented substantially perpendicular to the recommended line of traction of the elastic band 40 on the shell 10, the head being connected to the shell by a rod of smaller section. To hang the band 40 on the button 13, the user orients the buttonhole 41 substantially along the long axis of the head of the button 13, as illustrated in Figure 5.

The presence of a single point of traction on the shell 10 on each side of the latter at a relatively small distance from the rear edge 19, for example less than 15mm, avoids wrinkling its wall and thus reduces the risk of creating an air passage between the rear edge 19 of the shell 10 and the skin of the face. Preferably, each button 13 is positioned on the shell 10 such that when the mask is observed from the side, the angle formed between the axis X of the collar 16 and the line L joining the center of the button 13 with the intersection of the axis X of the neck 16 and of the front face of the grid 80, i.e. between 10 and 20°, being for example close to approximately 15°, as illustrated in FIG. 8. The orientation of the traction of the elastic band allows the mask to be pressed against the face, the elastic band passing over the ears of the wearer of the mask.

The rear part 11 of the shell 10 is made with a relatively small thickness e of material, preferably less than or equal to 0.3 mm, for example equal to 0.25 mm.

This very small thickness is present in the example illustrated over the entire periphery of the rear part 11, including on the rounding of the rear edge 19, which confers great flexibility on the mask and good adaptability to the morphology of the face. .

The bosses 12a and 12b can be made with the same thickness of material as the rear part 11 up to the zone forming a shoulder 72 where the wall of the shell 10 becomes thicker.

The illustrated mask 1 is particularly suitable for additive manufacturing, but the invention is not limited to the manufacture of the mask by 3D printing technology and the shell can also be made by injection molding.

In the context of additive manufacturing, several shells can be produced within the same manufacturing batch, in the same manufacturing tank, in a configuration where the masks are stacked, as illustrated in figure 14. An angle of tapering the bosses 12a and 12b by around fifteen degrees makes it possible to obtain a good compromise between the number of shells that can be manufactured in this stacked configuration and the absence of unwanted material melting between adjacent shells. The 3D printer used is for example a Multi Jet Fusion type printer from Hewlett Packard, but the invention is not limited to a particular additive manufacturing technology and other additive manufacturing technologies, for example of the SLS type. , can be used.

Identical shells 10 can be manufactured in the same batch, by playing on the adaptability of the mask 1 to the shape of the face thanks to the high deformability of the shell 10.

It is also possible to personalize the shape of the shell 10 to the morphology of the face of the wearer, by drawing the contour of the shell 10 to measure to take account of the shape of the face.

In this case, the user can send at least two frontal and profile photographs of his face, or even a more complete scan produced by filming his face at 180°, and the optimal shape to be given to the shell 10 is generated from of this information. In particular, it is possible to play on the taper of the rear part 11 and its length, from one mask to another, depending on the shape of the face.

The material in which the shell 10 can be made is for example a polyamide, preferably a biosourced polymer such as polyamide 11.

Where appropriate, the polymeric material of the mask includes a biocidal agent. Alternatively, the mask is coated, for example by spraying, with a biocidal coating.

The holding element 20 can be produced by the same additive manufacturing technique as the shell 10, or alternatively by a different manufacturing technique, for example by injection molding.

The fact of making the holding element 20 in the form of a separate part makes it possible to stack the shells 10, and thus to gain in productivity in the case of additive manufacturing.

To assemble the mask 1, the fixing part 21 is engaged on the collar 16 at the front, and locked on the latter by rotating it.

This then leads to the configuration illustrated in Figure 6, with flats 24 engaged in the groove formed between the collar 18 and the shoulder 72 at the base of the neck 16.

The filtering material 30 can then be placed in its housing, delimited by the post 26 present at the periphery of the fixing part 21, as illustrated in FIG. 6.

In the example illustrated, the filter material 30 is a cotton disc, of the type used to remove make-up. It is possible to use any type of filtering material, and in particular with reinforced filtration power, for example of the FFP2 type.

The filtering material bears by one side against the grid 80 and is kept pressed against the latter by the grid 28 of the retaining part 22, when the latter is folded back against the fixing part 21. The retaining part 22 is fixed in the fixing part 21, in the example considered, by tightening its raised edge 90 against the upright 26. Thus, the retaining part 22 can be pushed more or less into the fixing part 21 until the desired tightening of the filtering material 30. The clamping of the edge of the retaining part 22 against the upright 26 makes it possible both to obtain a relatively airtight assembly forcing the air to pass through the impermeable material, and on the other hand to allow an assembly with a degree of freedom in the X axis, making it possible to accommodate more or less thick filtering materials, or even several thicknesses of filtering materials, of the same nature or not.

During use, the shell 10 can undergo an overall deformation allowing it to match the shape of the user's face, thanks to the flexibility of the rear part 11, produced with a very small thickness, this flexibility n being unduly upset by the presence of bosses 12a and 12b which extend set back from the rear edge 19. The outward rounding formed by the latter makes it possible to increase the bearing surface against the skin and avoids thus to injure it, without providing too much rigidity to the rear part due to the outward orientation of this edge. The low thickness of the shell material makes the mask light and also contributes to the comfort of the mask, as does the width of the unique elastic band.

After use, the filter material 30 can be removed. To do this, the user opens the housing which contains it by pulling on the retaining part 22, this operation being facilitated by the presence of the rim 91 which protrudes slightly towards the outside of the upright 26.

Then, the mask can be cleaned by being placed in a dishwasher for example. You can optionally remove the elastic band before placing the mask in the dishwasher.

The invention is not limited to the example which has just been described, and many modifications can be made to the invention without departing from its scope.

For example, the holding element 20 can be made differently.

By way of example, FIG. 9 shows a variant of mask 1 in which the filtering material is held in the reception zone thereof by a holding element 20 in the form of a ring engaged at the inside the mask 1 from behind, and pinching the filtering material at its periphery against a corresponding seat of cylindrical shape, formed in an internal reception zone 17, at the front of the shell 10.

In the variant illustrated in FIG. 10, the holding element 20 is in the form of a cover which is engaged by the front of the mask on the reception zone 17, and clamps the filtering material 30 on a seat corresponding, of cylindrical shape of revolution. In this figure, the possibility of superimposing several thicknesses of filtering material 30 has been illustrated.

In the example of FIG. 11, the holding element 20 is arranged to be fixed on a neck formed at the front of the shell 10 in the reception zone 17, by any means, for example by screwing, friction, including cone on cone, snap or bayonet-type attachment. A fixing providing a clamping of the filtering material during the fixing of the holding element, such as a fixing of the quarter-turn type, is advantageous.

The holding element 20 has a housing defined between two walls, opening out through a slot 61 allowing the introduction of the filtering material 30 between them. The holding element 20 may have a grid against which the filtering material 30 is clamped by the front edge of the neck.

In the variant shown in Figure 13, the hull 10 is made without the side bosses, with a grid 98 at the front, bordered by a reinforcing bead 96 which extends all around the reception area 17 of the holding element 20. The latter is formed with a grid 97, and the filter material (not shown in this figure) is placed on the grid 98 before attaching the holding element 20 to the latter. The fixing of the holding element is effected for example by snap-fastening or by any other suitable means. In the case where the shell 10 is produced by additive manufacturing, it is advantageous to produce the retaining element in the form of a part produced separately, so as to allow the manufacture of the shells in a stacked form. In the case of manufacture of the shell by injection, it may be advantageous to mold the retaining element 20 at the same time as the shell 10 and in the same mold, the retaining element 20 then being connected to the shell. by a bridge of material forming a hinge for example, allowing it to be folded over the reception zone 17. In the example of FIG. 13, the rear part 11 of the shell 10 can be made with the same shape as that of the shells of examples of embodiments previously described, and in particular with a thin wall thickness at the rear edge 19 in particular. .

Of course, the shape of the shell and that of the holding element can be further modified in other variants, not illustrated. The holding element can be produced independently of the shell, as illustrated, or alternatively with the shell by being connected to the latter by a bridge of material, breakable or not, such as a hinge for example, allowing then return the element to the reception area provided for this purpose on the hull. It is still possible to use in certain variants as a holding element an O-ring, engaged on a corresponding seat made at the front of the hull.

Claims (26)

Respiratory protection mask (1), comprising:

• a plastic shell (10) to be placed on the face, this shell comprising:
  • a flexible rear part (11) without added seal, having a rear edge (19) adapted to match the shape of the face, the rear part (11) being made with a wall thickness (e) of between 0.15 and 0, 5 mm on at least part of its circumference, and
  • a front part provided with a zone for receiving (17) an element for holding a filtering material (30).

Mask according to claim 1, the front part comprising two lateral bosses (12a, 12b) whose rear ends (70) are remote from the rear edge (19) of the shell and which are connected at the front to said reception area ( 17). Mask according to one of claims 1 and 2, the rear part (11) being made with a wall thickness of between 0.15 and 0.5 mm all around, better still of between 0.15 and 0.4 mm, even better between 0.15 and 0.35mm. Mask according to any one of the preceding claims, the shell (10) having a material thickness, on its rear edge (19) in contact with the skin, of less than 0.3 mm. Mask according to any one of the preceding claims, the shell being produced by 3D printing. Mask according to any one of the preceding claims, the holding element (20) for the filtering material (30) comprising a part (21) for fixing to the shell (10), defining a housing for receiving the filtering material, and a filter media retaining portion (22) configured to attach to the attachment portion. Mask according to the preceding claim, the retaining part (22) being connected by a hinge (23) to the fastening part (21). Mask according to the preceding claim, the housing for receiving the filtering material (30) being of circular outline, adapted to receive a disc of filtering material. Mask according to any one of the preceding claims, the shell (10) being formed at the front with a grid (80; 98) integral with the remainder thereof. Mask according to any one of the preceding claims, the holding element (20) of the filtering material (30) being arranged to be mounted on the shell by a screw-in, snap-in, cone-on-cone or bayonet-type fixing. . Mask according to any one of the preceding claims, the holding element (20) being arranged to press the filtering material (30) against the shell (10) once fitted. Mask according to any one of claims 1 to 5, the element for holding the filtering material being arranged to be fixed from the inside on the shell. Mask according to the preceding claim, the holding element (20) being in the form of a ring. Mask according to any one of claims 1 to 5, the holding element being arranged to be fixed from the outside on the shell. Mask according to any one of claims 12 to 14, the holding element (20) of the filtering material being arranged to be fixed on the shell by pinching or pressing the filtering material against the shell so as to ensure its maintenance. Mask according to any one of the preceding claims, comprising two buttons (13) integral with the shell, for attaching an elastic band (40), preferably single, these buttons preferably having an oval, elongated head in a direction perpendicular to the direction of traction of the elastic band. Mask according to any one of the preceding claims, with an attachment to claim 2, the side bosses (12a, 12b) having the same thickness of material as the rear part (11) of the shell, at least over the major part of their length. Mask according to any one of the preceding claims, the rear part of the shell terminating in a rounded edge (19) directed outwards. Mask according to any one of the preceding claims, with an attachment to claim 2, the rear end of the bosses (12a, 12b) being separated by a distance (d) of at least 15mm from the rear edge (19) of the shell and/or the radius of curvature (R) of the side bosses (12a, 12b) at their top and at mid-length thereof being between 20 and 30 mm. Mask according to any one of the preceding claims, with an attachment to claim 2, the side bosses (12a, 12b) having a taper of between 10 and 20°. Mask according to any one of the preceding claims, with an attachment to claim 2, the rear part (11) having a taper greater than that of the side bosses (12a, 12b), at least on the sides. Mask according to any one of the preceding claims, with an attachment to claim 2, the side bosses (12a, 12b) connecting at the front to a thicker neck (16), at least partially defining the reception zone ( 17). Mask according to any one of the preceding claims, the shell at least being made of polyamide 11, optionally incorporating a biocidal agent, the shell preferably being made of a material which can be washed in the dishwasher and/or sterilized in an autoclave. A method of manufacturing a mask according to any preceding claim, wherein the mask manufacturing technique is an additive manufacturing technique or an injection molding technique. Method according to the preceding claim, a batch of several shells (10) of stacked masks being produced by additive manufacturing in the same manufacturing tank. Method according to one of Claims 24 and 25, in which the manufacture of the mask is carried out by an additive manufacturing technique and in which a file is generated making it possible to control a 3D printer used for the manufacture of the shell (10), from information on the morphology of the person intended to wear the mask, in particular from an at least partial 3D scan of the face of the latter.