FACE PROTECTION DEVICE WITH VISUAL INDICATOR FOR EXPOSURE TIME

Description

[0001] The present invention relates to a device that visually indicates the end of the useful life of a face protective device against biological agents, hereinafter referred to as mask.BACKGROUND OF THE INVENTION

[0002] Air pollution is widely acknowledged as a major risk factor for global public health, causing thousands of premature deaths in Europe each year, as well as cardiovascular and pulmonary diseases that affect millions of patients. The size of the pollutants plays a determining role, as the smallest particles are the most likely to become airborne and, therefore, to be more dangerous. In fact, particles larger than 10 µm are usually collected in the upper portion of the respiratory system and thus cannot enter the deep portion of the lungs. However, particles smaller than 10 µm are breathable, which means that they are capable of penetrating deep into the lungs. Those particles include, inter alia, bacteria, viruses, clay, silt, tobacco smoke and metallic fumes. The European Environment Agency (EEA) estimated that there were 417,000 premature deaths in 2018 that can be attributed to particulate matter (PM) with a diameter <2.5 µm (PM2.5), this size range being considered as most dangerous.

[0003] A container comprising an exposure time indicator for oxidising gases in the environment is known from US2006110835A1.

[0004] Furthermore, the unexpected emergence of the coronavirus (COVID-19) has raised concerns about whether air pollution may increase the severity of the illness and the risk of death after infection, as well as facilitate the spreading of severe acute respiratory syndrome by coronavirus 2 (SARS-CoV-2) or other pathogens of respiratory infectious diseases, such as tuberculosis and measles or influenza (H1N1 A).

[0005] The danger of pollutants in the air can be solved through the application of basic controls, such as increasing ventilation, providing suitable filter media in rooms or providing workers with protective equipment, such as protective masks.

[0006] Likewise, protective masks have been widely used by hospital staff, laboratory researchers, construction site workers, as well as the general public in highly polluted areas or during flu season. These are made up of a filtering barrier, which is a critical component that determines the level of protection of the mask, as the filtering efficiency depends on the particle size and the speed of the air flow.

[0007] Since the 2019 pandemic, the use of masks for long periods of time is becoming more and more frequent for users. This can lead to breathing difficulties, and to a greater sensation of feeling overwhelmed and congested, due to the accumulation of carbon dioxide and moisture inside the mask. In addition, prolonged mask use for several hours in a row causes the same air to be recirculated over and over again, causing discomfort during breathing, favouring congestion and causing loss of filtering efficiency. Here, we would be talking about a mask that has exhausted the minimum protection capacity thereof. In fact, there are maximum use times that are limited for the different types of masks, which, nevertheless, still lack a system that visually indicates the end of the useful life thereof. In this manner, we are currently faced with the impossibility that the user himself, and other people who come into contact therewith, know in an easy and direct manner the moment when their mask is no longer useful and must be therefore discarded and replaced with a new one, with the corresponding health risks that this entails.DESCRIPTION OF THE INVENTION

[0008] A chemical reaction or mechanism is described that is modified during the use time of the mask. The components that form part of the reaction will be contained in some type of specific compatible carrier that will later be adhered or included in the mask during the manufacturing process.

[0009] The colouring is indigo blue, very insoluble in water, which undergoes a chemical reduction process with sodium dithionite (Na 2 S 2 O 4 ) in basic medium. Under these conditions, indigo turns from its characteristic blue to a completely soluble and translucent yellowish colour (Fig. 1). From this point, the colour change timing is modulated by using what we call "sacrificial reagent", which is nothing more than an excess of the reducing agent (sodium dithionite) that is consumed as the oxygen enters, maintaining the yellow colour during the use of the device, until it is finished and the colour change begins, indicating the end of the use time of the mask.

[0010] Disclosed is a protective device with visual exposure time indication system and loss of effectiveness comprising a face protective device, comprising two sides, a first internal side, configured to be in contact with the skin of a subject using the face protective device; and a second external side configured to be in contact with the air; and an exposure time indicator through colour change characterised in that it comprises a container that is semi-permeable to oxygen with a surface of 0.5 to 5 cm by 0.5 to 5 cm, adhered by means of a system selected from an adhesive, heat sealing and ultrasonic sealing, on the second side of the face protective device, and in that the container comprises between 0.1 ml and 3 ml of a basic aqueous solution at a pH between 10 and 14 containing a mass ratio between indigo and sodium dithionite between 1:0.7 and 1:1.8.

[0011] A protective device according to the invention is defined in claim 1.

[0012] Said device has the advantages that by having placed the expiration indicator close to an area where the mask is in contact with the skin, body temperature aids in minimising the effect of external temperature for temporary exposures. In addition, the airflow required to effectively influence the colour change timing is well above normal respiratory flow. The reagents, being completely isolated by the container that is semi-permeable to oxygen and the small amount thereof, do not pose a risk to whoever is using the device. The mass ratio between indigo and sodium dithionite at 1:0.7 is equivalent to 1.1 dithionite equivalents, and it is the minimum required to reduce all the indigo, making a colour change towards translucent yellow. With a mass ratio of 1:1.5, an excess of sacrificial reagent is included so that, once the mask is exposed to the air, the estimated time for all of the indigo to oxidise and change colour back to its original blue is 8 h.

[0013] In the present invention, "air" is understood as the gaseous, transparent, odourless and tasteless substance that envelops the Earth and forms the atmosphere; it is mainly made up of oxygen and nitrogen, and varying amounts of argon, water vapour and carbon dioxide and may comprise bacteria, viruses, clay, silt, tobacco smoke and metallic fumes. In a preferred embodiment, the container that is semi-permeable to oxygen is made of a heat-sealable polymer. More preferably the heat-sealable polymer is selected from polypropylene, PVC, polyamide, cellulose acetate and any combination of the above.

[0014] In another preferred embodiment, the container that is semi-permeable to oxygen is made of a polymer that can be sealed using ultrasound. More preferably the polymer that can be sealed using ultrasound is selected from polypropylene, PVC, polyamide, cellulose acetate and any combination of the above.

[0015] In another preferred embodiment, the container that is semi-permeable to oxygen is made of a heat-sealable polymer or of a polymer that can be sealed using ultrasound, wherein said heat-sealable polymer or polymer that can be sealed using ultrasound is selected from polypropylene, polyamide PVC, cellulose acetate and any combination of the above.

[0016] In another even more preferred embodiment, the thickness of the heat-sealable polymer container is between 40 µm and 100 µm. And even more preferably between 50 µm and 90 µm.

[0017] In another preferred embodiment, the size of the container surface is 2.5 cm to 3.5 cm by 2.5 cm to 3.5 cm.

[0018] In another preferred embodiment, the adhesive is selected from epoxy resins, cyanoacrylates, polyurethanes, silicones, acrylics, phenolics, polyimides, vinyls, neoprene and any combination thereof.

[0019] In another preferred embodiment, the pH is between 10.5 and 11.5. The advantage of said pH range is that the solution is the least caustic possible and therefore less dangerous both for the container that is semi-permeable to oxygen and for the user who uses the protective system.

[0020] In another preferred embodiment, the basic aqueous solution is selected from a solution comprising NaOH, KOH, RbOH, CsOH, Be(OH) 2 , Mg(OH) 2 , Ca(OH) 2 and any combination of the above.

[0021] In another preferred embodiment, the basic aqueous solution is NaOH and the pH is 11.

[0022] In another preferred embodiment, the mass ratio of indigo with sodium dithionite is 1:1. With a mass ratio of 1:1, the estimated time to oxidise all the indigo and for the colour change to occur is 4 h. Said value coincides with the recommended use time of some face protectors.

[0023] In another preferred embodiment, the mass ratio of indigo with sodium dithionite is 1:1.5.

[0024] With a mass ratio of 1:1.5, the estimated time to oxidise all the indigo and for the colour change to occur is 8 h. Said value coincides with the recommended use time of different long-lasting face protectors.

[0025] In a preferred embodiment, the face protective device is selected from a 1-ply surgical mask, 3-ply surgical mask, N95 mask, KN95 mask, KF94 mask, FFP1 mask, FFP2 mask with and without exhalation valve, FFP3 mask with and without exhalation valve.

[0026] In a more preferred embodiment, the face protective device is a 3-ply surgical mask, and wherein the exposure time indicator through colour change comprises a polypropylene container with a surface of 3 cm x 2.5 cm, adhered by means of an adhesive on the second side of the mask, and comprising 1 ml of an aqueous solution of NaOH at pH = 11 containing 2 mg of Indigo, 2 mg of sodium dithionite.

[0027] In a more preferred embodiment, the face protective device is an FFP2 mask without an exhalation valve, and wherein the exposure time indicator through colour change comprises a polypropylene container with a surface of 3 cm x 3 cm, adhered by means of an adhesive on the second side of the mask, and comprising 1.1 ml of an aqueous solution of NaOH at pH = 11 containing 2 mg of Indigo, 2.6 mg of sodium dithionite.

[0028] According to the invention, the indicator device in which the container that is semi-permeable to oxygen comprises the solid reagents (indigo and dithionite in the corresponding proportions) and a capsule inside containing the basic aqueous solution and wherein said capsule is configured to be broken.

[0029] In another preferred embodiment, the indicator device further comprises insulating means, preferably airtight and impermeable to oxygen, adjacent to the expiration indicator device, and enveloping said indicator device completely, and wherein said means are configured to be removed, withdrawn and / or broken. In a more preferred embodiment, the insulating, airtight and impermeable medium is a Nylon bag with a thickness of at least 0.24 mm.

[0030] Also disclosed is a kit characterised in that it comprises I. an airtight container that is impermeable to oxygen configured to be removed; and II. the protective device with the visual indication system described above inside the airtight container.

[0031] A kit according to the invention is defined in claim 14.

[0032] Throughout the description and the claims, the word "comprises" and its variants do not intend to exclude other technical features, additives, components or steps. For those skilled in the art, other objects, advantages and features of the invention may be partially deduced from both the description and the embodiment of the invention. The following examples and figures are provided by way of illustration and are not intended to limit the present invention.BRIEF DESCRIPTION OF THE FIGURES

[0033] Fig. 1. Reactions involved in the transformation of indigo (blue) into leucoindigo (translucent yellow).EXAMPLES

[0034] Next, the invention will be illustrated by means of assays carried out by the inventors, which demonstrate the effectiveness of the product of the invention.Example 1

[0035] It is a container that is semi-permeable to oxygen made of AG194 polypropylene (Avery Dennison) 60 microns thick with a surface of 3 cm x 2.5 cm glued on a surgical mask, comprising therein 2 mg of Indigo (Sigma-Aldrich), 2 mg of sodium dithionite (Sigma-Aldrich) and 1 ml of an aqueous solution of NaOH at pH = 11. To prevent the errors caused by manual preparation of devices, a sample of 5 devices prepared with this recipe was used, obtaining an average colour change beginning at 3 h and resulting in a definitive darkening at 4 h.Example 2

[0036] It is a container that is semi-permeable to oxygen made of AG194 polypropylene (Avery Dennison) 60 microns thick with a surface of 3 cm x 3 cm glued on an FFP2 mask, comprising therein 2 mg of Indigo (Sigma-Aldrich), 2.6 mg of sodium dithionite (Sigma-Aldrich) and 1.1 ml of an aqueous solution of NaOH at pH = 11. To prevent the errors caused by manual preparation of devices, a sample of 6 devices prepared with this recipe was used, obtaining an average colour change beginning at 7.2 h and resulting in a definitive darkening at 8.1 h.

Claims

1. A protective device with visual exposure time indication system and loss of effectiveness comprising • a face protective device, comprising two sides, a first internal side, configured to be in contact with the skin of a subject using the face protective device; and a second external side configured to be in contact with the air; and • an exposure time indicator through colour change characterised in that it comprises a container that is semi-permeable to oxygen with a surface of 0.5 to 5 cm by 0.5 to 5 cm, adhered by means of a system selected from an adhesive, heat sealing and ultrasonic sealing, on the second side of the face protective device; and wherein the container that is semi-permeable to oxygen comprises the solid reagents indigo and dithionite in mass proportions between 1:0.7 and 1:1.5 and a capsule inside containing 0.1 ml to 3 ml of a basic aqueous solution at a pH between 10 and 14 and wherein said capsule is configured to be broken.

2. The device according to claim 1, wherein the polymer container is adhered by means of an adhesive selected from among epoxy resins, cyanoacrylates, polyurethanes, silicones, acrylics, phenolics, polyimides, vinyls, neoprene and any combination thereof.

3. The device according to claim 1, wherein the container that is semi-permeable to oxygen is made of a heat-sealable polymer or of a polymer that can be sealed using ultrasound, wherein said heat-sealable polymer or polymer that can be sealed using ultrasound is selected from polypropylene, polyamide PVC, cellulose acetate and any combination of the above.

4. The device according to any of claims 1 to 3, wherein the thickness of the polymer container is between 40 µm and 100 µm.

5. The device according to claim 4, wherein the thickness is between 50 µm and 90 µm.

6. The device according to any of claims 1 to 5, wherein the size of the container surface is 2.5 cm to 3.5 cm by 2.5 cm to 3.5 cm.

7. The device according to any of claims 1 to 6, wherein the basic aqueous solution is selected from a solution comprising NaOH, KOH, RbOH, CsOH, Be(OH)2, Mg(OH)2, Ca(OH)2 and any combination of the above.

8. The device according to any of claims 1 to 7, wherein the basic aqueous solution is NaOH and the pH is 11.

9. The device according to any of claims 1 to 8, wherein the face protective device is selected from 1-ply surgical mask, 3-ply surgical mask, N95 mask, KN95 mask, KF94 mask, FFP1 mask, FFP2 mask with and without exhalation valve, FFP3 mask with and without exhalation valve.

10. The device according to claim 9, wherein the face protective device is a 3-ply surgical mask, and wherein the exposure time indicator through colour change comprises a polypropylene container with a surface of 3 cm x 2.5 cm, adhered by means of an adhesive on the second side of the mask, and comprising therein 2 mg of indigo, 2 mg of sodium dithionite and 1 ml of an aqueous solution of NaOH at pH = 11.

11. The device according to claim 9, wherein the face protective device is an FFP2 mask without an exhalation valve, and wherein the exposure time indicator through colour change comprises a polypropylene container with a surface of 3 cm x 3 cm, adhered by means of an adhesive on the second side of the mask, and comprising 2 mg of indigo, 2.6 mg of sodium dithionite and 1.1 ml of an aqueous solution of NaOH at pH = 11 inside.

12. The device according to any of claims 1 to 11, wherein the indicator further comprises insulating means adjacent to the container, and enveloping said indicator completely, and wherein said means are configured to be removed, withdrawn and / or broken.

13. The device according to claim 12, wherein the insulating, airtight and impermeable medium is a Nylon bag with a thickness of at least 0.24 mm.

14. A kit characterised in that it comprises i. an airtight container that is impermeable to oxygen configured to be removed and / or broken; and ii. the protective device with visual indication system according to any of claims 1 to 13, inside the airtight container that is impermeable to oxygen.