Lightweight Respiratory Mask

Abstract

Disclosed is a particularly lightweight breathing mask for respiratory applications or as personal protective equipment, in which the rigid component is produced from thermoplastic films by means of high-pressure forming. The base material of the rigid component is available in a flat form and can thus be printed or coated in a variety of ways before processing; this allows properties to be introduced into the mask that would not be feasible in a conventional injection molding process. The use of film instead of injection-molded components enables a significant reduction in weight and thus an improvement in wearing comfort for the user. At the same time, the film allows a higher degree of flexibility of the rigid component during operation, enabling a better fit to the shape of the face under certain operating conditions and thus also improving wearing comfort

Claims

1. a hollow dome made of plastic, preferably transparent plastic, for use in a respirator or respiratory therapy mask or in sports equipment or personal protective equipment, wherein the base material of the dome is present in the form of a plastic film which is formed into a three-dimensionally shaped form by means of high-pressure forming and is then trimmed to the required outer and optionally inner contours.

2. a hollow dome according to claim 1, which has a significantly lower weight, preferably 0.2 to 0.6 times the weight, more preferably 0.3 to 0.5 times the weight of a comparably shaped injection-molded dome, and thereby improves the comfort for the user.

3. a hollow dome according to claim 1, wherein the starting material, which comes in the form of a plastic film, has a thickness in the range from 0.1 mm to 1.0 mm, preferably from 0.3 mm to 0.7 mm, more preferably from 0.4 mm to 0.6 mm.

4. a hollow dome according to claims 1-3, wherein the starting material consists of a thermoplastic, preferably polycarbonate, further preferably high temperature polycarbonate.

5. a hollow dome according to claims 1-4, in which the rigid component retains a degree of flexibility after forming, so that a controlled elastic deformation can take place in operation which positively influences the wearing comfort on the face.

6. a degree of flexibility of a film formed into a hollow dome according to claim 5, which allows an elastic deformation between 10% and 50%, preferably between 20% and 40%.

7. a hollow dome according to claims 1-6, which is joined to a sealing lip of silicone or thermoplastic elastomer to achieve a sealing effect on the face of the support, and in which the sealing lip is either attached to the formed film, or is preferably injection molded to the formed film by a multicomponent injection molding process.

8. a hollow dome according to claims 1-6 as well as according to claim 7, wherein the starting material is coated prior to forming, preferably with one or more printing inks, which are maintained on the three-dimensional shape of the hollow dome after forming of the film.

9. a coating according to claim 8, which includes electrically conductive inks

10. a coating according to claim 9, in which electrical components are also applied to the starting material before forming.

11. an application of electrically conductive inks to the base material of a hollow dome according to claims 9-10, by means of which conductive tracks for capacitive switches are formed in the hollow dome of the mask which in turn can be used to control devices connected to the mask, for example respirators.

12. an application of electrically conductive inks to the base material of a hollow dome according to claims 9-11, in which the inks form contacts for subsequently applied sensor elements.

13. an application of electrically conductive inks to the base material of a hollow dome according to claims 9-12, in which the inks form conductive paths as antennas for short-range wireless communications.

14. a hollow dome according to claims 1-8, wherein printing inks are applied that wear, fade, abrade or intentionally delaminate over time.

15. a wear indicator according to claim 14, in which the wear of the printing ink occurs continuously through normal handling and cleaning of the hollow dome, for example through cleaning agents or UV light, and thus visually indicates the service life of the mask system.

16. a hollow dome according to claims 1-7, wherein the film is coated with a second material, such as wood, metal or cellular fibers, sufficiently thin to also be converted into a three-dimensional shape upon forming.

Description

DESCRIPTION OF DRAWINGS

[0029] FIG. 1 shows an isometric view (11) of the formed rigid dome structure as seen from the outside, as it would be seen on a wearer's face, and another isometric view (12) as seen from inside the mask cushion cavity, the enclosure on the wearer's face. Several features are displayed here as examples, yet other shapes or embodiments are obviously also feasible. The rigid dome structure forms a part (111) of an enclosure on a wearer's face during use together with a subsequently overmoulded sealing portion, which is not shown here. Geometric features for receiving e.g. a wearer's nose (113) or chin (114) can be included. The rigid dome structure incorporates a planar flange (112) for forming part of a rotational interface to an air supply tubing. It also forms a flange area (115) along its outer perimeter for bonding to an elastic cushion portion during overmoulding. A conical structure (121) such as e.g. a standardized cone for connecting to respiratory tubing and accessories, is also formed as part of the rigid dome structure.

[0030] FIG. 2 shows a front view (21), a side view (22) and a cross-sectional view (23) of the formed rigid dome structure, again depicting the elements shown in FIG. 1, such as the planar flange (112) in (221), and the conical structure (121) in 231. FIG. 2 illustrates the very thin wall sections 232 achievable by forming a plastic film.

[0031] FIG. 3 shows two different embodiments of the rigid dome structure arrayed on a film sheet (33), the film sheet being characterized by an outer area (331) intended for retention in the forming tool, the inner area (332) enabling the deformation of the flat film sheet into the desired three-dimensional shape. One embodiment (31) shows a design more suitable for respiratory masks having a connection portion for an air supply tubing (312), as shown in FIG. 1 and FIG. 2, while the other embodiment is not intended to connect to an external air supply, such as might be the case in sports or personal protective equipment. In a manufacturing step subsequent to the high-pressure forming, both embodiments are trimmed at an external contour (311, 321), while the first embodiment (31) also is trimmed at an inner contour (312), to achieve the finished rigid dome structure which is then overmoulded with a sealing or face contact portion.

[0032] FIG. 4 shows a cross sectional view (41) through the formed film already shown in FIG. 3. A flat plastic material (411) is heated and formed into a three-dimensional shape by application of an elevated air pressure as known from the prior art. The film can be formed into a negative, or downward portion (412) of the forming tool, and the central areas of the forming tool can be raised (413) above the parting plane (414) so that it already forms a portion of the three-dimensional shape as the tool closes. Both effects combined allow for a maximized height of the formed rigid dome structure, while ensuring a uniform film stretch. In the present embodiment, the high-pressure forming tool is located on the lower side (415) of the film sheet, it is however obvious that the forming tool could also be located on the opposite side (416), so that the film sheet is formed face down. Such a face down forming may be advantageous in case conductive tracks or sensitive inks or coatings are pre-applied to the film, which cannot endure contact with the forming tool.

[0033] FIG. 5 shows another cross sectional view (51) of the formed rigid dome structure shown in the previous figures, depicting a second layer (511), e.g. a printing or coating layer, applied to the outside of the film prior to the high-pressure forming process. As the high-pressure forming process is dimensionally more accurate and more repeatable than vacuum forming or low-pressure forming, it is possible to position the second layer such that important areas of the formed rigid dome structure are not coated in the finished part, such as the flange intended for bonding during overmoulding (512) or the conical standardized connector portion (513). While FIG. 5 shows a coating applied to the outside of the formed rigid structure, it is obvious that printings or coatings may also be applied to an inside portion (514) of said structure, or to both the outside and the inside portions.