Method of manufacturing full face mask for air purification respirator and such full face mask

Abstract

A method of manufacturing a full face mask (1) for an air purification respirator (APR) or powered air purification respirator (PAPR) is disclosed, the method comprising the steps of: providing a sheet (100) made of a first transparent polymeric material; cutting a window (10, 110) from the sheet material; forming the window (10, 110) into a three-dimensional shape; and forming a frame (20, 120) around the window (10, 110) by injection molding a second material onto the perimeter (11, 111) of the window in a first mold (103). A full face mask for an APR or PAPR is also disclosed.

Description

Technical Field

[0001] The present invention relates generally to air purifying respirators (APR) and powered air purifying respirators (PAPR), and more particularly to a method of manufacturing a full-face mask for an APR or PAPR. The present invention also discloses a full-face mask for an APR or PAPR. Background Art

[0002] An air purifying respirator is an air filtering device that removes contaminants by filtration or absorption, preventing the inhalation of large and small particles. Air purifying respirators can be passive PAPRs, or active PAPRs. PAPRs have significant advantages over APRs because PAPRs require only a simple fit test and do not increase the work of breathing. Because PAPRs provide positive pressure inside the mask, they also reduce the risk of leakage into the mask due to the growth of beards, wrinkles, etc.

[0003] When using APRs and PAPRs, it is important that they provide a wide and undistorted field of view and are lightweight and comfortable to wear. APRs and PAPRs can be used in many different environments, for many different purposes and for many different applications. Such different conditions of use require that the full-face mask exhibit correspondingly different properties. For example, if the APR / PAPR is intended for use at different ambient temperatures, such as for fire fighting, indoors at room temperature, or outdoors at cold or extremely cold temperatures, the material forming the full-face mask should exhibit different properties. In certain applications, the material needs to withstand the erosion of the surrounding environment. In addition, certain applications may require that the window of the full-face mask exhibit certain material-dependent properties, such as sun protection, anti-reflection or anti-scratch properties. For these reasons, it is necessary to provide a method for manufacturing a full-face mask that allows free selection of the material used to form the full-face mask.

[0004] WO 2011 / 159233 A1 discloses a full face mask for PAPR. The full face mask is made of transparent plastic in one piece by a one-step vacuum forming process, and has a single arc-shaped field of view. The face seal can be made as a single piece by vacuum forming and cutting out a central opening suitable for the full face mask. The face seal is then bonded to the full face mask. Alternatively, the face seal can be formed integrally with the full face mask in a one-step vacuum forming process. Summary of the invention

[0005] It is an object of the present application to provide an improved method of manufacturing a full-face mask for use with an APR or PAPR.

[0006] Another object is to provide such a method which allows a great deal of freedom in the choice of materials comprised in the full-face mask.

[0007] Another object is to provide such a method by which a full-face mask can be manufactured at low cost.

[0008] A further object is to provide a method which allows manufacturing at high speed.

[0009] Yet another object is to provide an improved full face mask for an APR or PAPR.

[0010] In general, unless otherwise expressly defined herein, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field. Unless otherwise expressly stated, all references to "a / an / the element, means, component, mode, step, etc." should be broadly understood to refer to at least one example of the element, means, component, mode, step, etc. Unless otherwise expressly stated, the steps of any method disclosed herein do not have to be performed in the exact order disclosed.

[0011] According to a first aspect, the present application provides a method of manufacturing a full face mask for an APR or PAPR as defined in the accompanying claim 1. The method comprises the steps of providing a sheet made of a first transparent polymer material; cutting a viewing window from the sheet; forming the viewing window into a three-dimensional shape; and forming a frame around the viewing window by injection molding a second material onto the periphery of the viewing window in a first mold.

[0012] The method thus enables full-face masks including a window and a frame surrounding the window to be manufactured at high speed and low cost, while still allowing the window and frame to be manufactured from a variety of different materials using the same production line.

[0013] The viewing window may be formed into a three-dimensional shape in a separate bending or thermoforming operation before being inserted into a first mold for injection molding a frame onto the perimeter of the viewing window.

[0014] However, in preferred embodiments, the step of forming the window into a three-dimensional shape is performed in a first mold by applying heat to the window and closing the first mold. Thus, in these embodiments, a planar window cut from a sheet of a first material is placed in a first mold and formed into a three-dimensional shape within the mold, and then the frame is injection molded onto the window. In this way, a separate operation of forming a three-dimensional window is eliminated.

[0015] The method may further include the step of forming a face seal around the frame by injection molding a third material onto a perimeter of the frame.

[0016] The step of forming the face sealing edge may be performed in a second mold different from the first mold.

[0017] The steps of forming the frame and the face seal edge can be performed in the same injection molding machine by 2K injection molding or multi-material molding.

[0018] The step of forming a frame around the window may include fusing or adhering the second material to the first material.Such fusing or adhering of the frame to the window may preferably be performed when the window and the frame comprise the same or chemically fusible or adherable material.

[0019] Alternatively or in combination, the step of forming a frame around the viewing window may include forming a mechanical joint between the frame and the viewing window. Such a mechanical joint between the frame and the viewing window may be performed in the case where the frame and the viewing window comprise non-fusible or non-adhesive materials and / or in the case where a particularly strong mutual fixation of the two components is required.

[0020] The step of forming the face seal around the frame may include fusing or adhering the third material to the second material.

[0021] Alternatively or in combination, the step of forming the face sealing edge around the frame may include forming a mechanical bond between the sealing edge and the frame. Such a mechanical bond between the face sealing edge and the frame may be performed in the case where the face sealing edge and the frame comprise non-fusible or non-adhesive materials and / or in the case where a particularly strong mutual fixation of the two components is required.

[0022] The first material may include PETG or PC.

[0023] The second material may be selected from the group consisting of PETG, PC, PA, PP, ABS and TPE.

[0024] Both the first material and the second material may comprise PETG or PC. By using the same material to form the window and the frame, it may be helpful to achieve fixation between the two components by fusing or adhering.

[0025] The third material may be selected from the group consisting of TPE, silicone and rubber.

[0026] The method may further comprise the step of coating at least one side of the viewing window with a layer of a fourth material. The fourth material may be, for example, a material exhibiting sun protection, anti-reflection and / or anti-scratch properties.

[0027] The step of coating the window with the fourth material layer may preferably be performed before the step of forming a frame around the window, for example before the step of forming the window into a three-dimensional shape.

[0028] According to a second aspect, the present application provides a full face mask for an air purifying respirator (APR) or a powered air purifying respirator (PAPR) as defined in independent claim 15. The full face mask comprises: a viewing window comprising a cut-out of a first transparent polymer sheet, the cut-out having been formed into a three-dimensional geometric shape; and a frame formed of a second material that has been injection molded onto the periphery of the viewing window.

[0029] The full face mask may also include a face sealing edge that has been injection molded onto the periphery of the frame.

[0030] Other objects and advantages of the method and the full-face mask appear from the following description of embodiments and from the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Various aspects and embodiments will now be described by way of example with reference to the accompanying drawings, in which:

[0032] Figure 1a is a perspective view of a full-face mask for a PAPR according to one embodiment.

[0033] Figure 1b FIG. 1 is an exploded perspective view of the full face mask shown in FIG. 1 .

[0034] Figure 2a to Figure 2c is a schematic diagram of various steps in an embodiment of a method of manufacturing a full-face mask. DETAILED DESCRIPTION

[0035] Various aspects of the present application will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the present application are shown.

[0036] However, these aspects can be embodied in many different forms and should not be construed as limiting. Instead, these embodiments are provided by way of example so that this application will be thorough and complete and fully convey the scope of all aspects of the application to those skilled in the art. The same number refers to the same element throughout the specification.

[0037] Figure 1a and Figure 1b An embodiment of a full face mask 1 for an APR or PAPR is shown. The full face mask 1 is manufactured by a manufacturing method as described below. The full face mask 1 includes a window 10, a frame 20 and a facial sealing edge 30. In use, the APR or PAPR includes additional components not shown in the figure. These components may include at least one filter unit, a blower or fan for providing positive pressure in the mask, a power supply, a valve device and a strap for fixing the mask so that the mask covers the wearer's face. These components and their functions are well known in the art and will not be described here.

[0038] The window 10 is formed of a sheet of transparent polymer material. Examples of materials used to form the window are PETG (polyethylene terephthalate) and PC (polycarbonate). However, other sheet-like transparent polymer materials with visual clarity, bendable or thermoformable into a three-dimensional shape can also be used to form the window. The window has a three-dimensional shape with an outer periphery 11.

[0039] The frame 20 is formed of an injection moldable polymer material. Examples of such materials include PETG, PA, PC (polycarbonate), PP (polypropylene), ABS (acrylonitrile butadiene styrene) and TPE (thermoplastic elastomer). The frame 20 has a three-dimensional shape having an outer periphery 21 and a central through hole 22 surrounded by an edge 23. The window 10 is accommodated in the central opening 22, and the periphery 11 of the window is fixed in a sealed manner along the edge 23 of the frame.

[0040] In the case where the window 10 and the frame 20 include mutually fusible and / or adhesive materials, for example, when the window 10 and the frame 20 both include PETG or PC, the mutual fixation of the two components can be achieved by material fusion and / or adhesion. In other cases or in addition, the window 10 and the frame can be fixed to each other by mechanical engagement. This engagement can, for example, include a U-shaped channel (not shown) that extends along the inner edge 23 of the frame 20 and tightly receives the outer periphery 11 of the window 10. This engagement can alternatively or in combination include mutually cooperating recesses and protrusions arranged along the periphery 11 of the window 10 and the inner edge 23 of the frame 20.

[0041] When the mutual fixation between the window 10 and the frame 20 is achieved by fusing, adhering or mechanical bonding, the mutual fixation between the two parts is completed when the frame 20 is injection-molded onto the periphery 11 of the window 10 during the first injection-molding operation.

[0042] The frame 20 also includes a second opening 24 for arranging a valve device and a filter unit (not shown), wherein the valve device and the filter unit are not described in further detail herein. These additional components are usually attached to the full-face mask 1 after the mask 1 including the window 10, the frame 20 and the face sealing edge 30 is completed.

[0043] The face seal 30 is arranged to contact the wearer's face in a sealing manner, thereby sealing the interior of the mask 1 from the surrounding atmosphere when in use. The face seal 30 is formed of a flexible polymer material that can be injection molded. Examples of such materials suitable for the face seal are TPE, silicone and rubber. The face seal 30 has a three-dimensional shape, which has an outer periphery 31 arranged to contact the wearer's face in a sealing manner and a central opening 32 surrounded by an edge 33. The frame 20 is received in the central opening 32, and the periphery 21 of the frame is fixed in a sealing manner along the edge 33 of the face seal 30.

[0044] In the case where the frame 20 and the face seal edge 30 include mutually fusible and / or adhesive materials, such as when both the frame 20 and the face seal edge 30 include TPE, the mutual fixation of the two components can be achieved by material fusion and / or adhesion. In other cases or in addition, the frame 20 and the face seal edge 30 can be fixed to each other by mechanical engagement. Such engagement can, for example, include a U-shaped channel (not shown) that extends along the inner edge 33 of the face seal edge and tightly receives the outer periphery 21 of the frame 20. Such engagement can alternatively or in combination include mutually cooperating recesses and protrusions arranged along the periphery 21 of the frame 20 and the inner edge 33 of the face seal edge 30.

[0045] The face sealing edge 30 further comprises a plurality of outwardly projecting flexible protrusions 34 which are arranged to be used for securing a strap (not shown) to secure the full face mask 1 to the wearer's head.

[0046] Figure 2a to Figure 2c An embodiment of a method of manufacturing a full-face mask for an APR or PAPR is schematically illustrated.

[0047] Figure 2a A first step is shown, wherein a sheet 100 made of a first transparent polymer material is provided on a roller 101 and fed to a punch 102 to punch a window 110 from the sheet 100. In some embodiments, a rolling mill (not shown) may be arranged between the roller 101 and the punch 102 for relaxing the material and enhancing the planarity of the sheet 100. After being punched from the sheet 100, the window has a substantially planar two-dimensional shape with an outer perimeter 111.

[0048] Figure 2b The second and third steps of the method are shown. A flat viewing window 110 is positioned in a mold 103 of a first injection molding machine. The mold 103 comprises two mold halves 103a, 103b and a channel 103c, wherein the channel 103c is used to provide an injectable material into the mold cavity.

[0049] After positioning the planar window 110 in the mold 103, the mold is closed. By closing the mold 103, the planar window is reshaped from a two-dimensional shape to a three-dimensional shape corresponding to the internal shape of the mold 103. During this reshaping of the window, heat may be applied to the mold 103, thereby applying heat to the window 110, so that the window is reshaped by thermoforming.

[0050] In the next step, the second material is injected into the interior of the mold 103 through the channel 103c. The interior shape of the mold is arranged so that the injected material contacts the outer periphery 111 of the window 110 and forms a frame 120 having a three-dimensional shape and having an outer periphery 121 around the window 110.

[0051] Figure 2c A further step of the method is shown. The three-dimensional assembly of the window 110 and the frame 120 is positioned in a mold 104 of a second injection molding machine. The mold 104 comprises two mold halves 104a, 104b and a channel 104c for providing the injectable material into the mold cavity.

[0052] After positioning the assembly of the window 110 and the frame 120 in the mold 104, the mold is closed. Then, the third material is injected into the interior of the mold 104 through the channel 104c. The internal shape of the mold is arranged so that the injected material contacts the outer periphery 121 of the frame 120 and forms a face seal edge 130 having a three-dimensional shape and having an outer periphery 131 around the assembly of the window 110 and the frame 120.

[0053] In an alternative embodiment of the method, not shown, Figure 2a After the stamping operation shown, the planar window 110 is re-formed into a three-dimensional shape in a separate bending or thermoforming operation and then positioned into the mold 103 to injection mold the frame 120 onto the perimeter 111 of the window 110 .

[0054] In another embodiment not shown, both injection molding operations are performed in the same injection molding machine. This can be achieved by a so-called 2K injection molding operation or a multi-material molding (MMM) operation. In such an operation, one of the mold halves is rotatable and includes two mold cavities. A flat window can be positioned in a first cavity, after which the mold is closed to reshape the window into a three-dimensional shape. Thereafter, a second material is injected to form a frame around the window. When the frame has been hardened, the mold is opened and the rotatable mold halves are rotated so that the closed two mold halves currently define a mold cavity for forming a facial sealing edge around the frame. Thereafter, a third material is injected into the mold cavity to form a facial sealing edge on the periphery of the frame.

[0055] In another embodiment not shown, the flat window is re-formed into a three-dimensional shape in a separate bending or thermoforming operation, followed by continuous formation of the frame and face seal edge by a 2K injection molding or MMM operation.

[0056] Various aspects of the present application are mainly described on the basis of reference to a few embodiments and examples thereof. However, as is readily appreciated by those skilled in the art, other embodiments than the embodiments disclosed above are equally possible within the scope of the present application as defined by the attached patent claims.

Claims

1. A method of manufacturing a full-face mask (1) for an air purifying respirator (APR) or a powered air purifying respirator (PAPR), the method comprising the steps of: Providing a sheet (100) made of a first transparent polymer material; cutting a viewing window (10, 110) from the sheet; forming the viewing window (10, 110) into a three-dimensional shape; as well as A frame (20, 120) is formed around the viewing window (10, 110) by injection molding a second material onto the periphery (11, 111) of the viewing window in a first mold (103).

2. The method according to claim 1, wherein: The step of forming the viewing window (10, 110) is performed in the first mold (103) by applying heat to the viewing window (10, 110) and closing the first mold (103).

3. The method according to claim 1 or 2, further comprising the following steps: A face seal edge (30, 130) is formed around the frame (20, 120) by injection molding a third material onto a periphery (21, 121) of the frame (20, 120).

4. The method according to claim 3, wherein: The step of forming the face sealing edge (30, 130) is performed in a second mold (104) different from the first mold (103).

5. The method according to claim 3 or 4, wherein: The steps of forming the frame and the face sealing edge are performed in the same injection molding machine by 2K injection molding or multi-material molding.

6. The method according to any one of claims 1 to 5, wherein: The step of forming the frame (20, 120) around the window (10, 110) comprises: The second material is fused or adhered to the first material.

7. The method according to any one of claims 1 to 6, wherein: The step of forming the frame (20, 120) around the window (10, 110) comprises: A mechanical joint is formed between the frame (20, 120) and the window (10, 110).

8. The method according to any one of claims 3 to 7, wherein: The step of forming the facial sealing edge (30, 130) around the frame (20, 120) comprises: The third material is fused or adhered to the second material.

9. The method according to any one of claims 3 to 8, wherein: The step of forming the facial sealing edge (30, 130) around the frame (20, 120) comprises: A mechanical bond is formed between the face sealing edge (30, 120) and the frame (20, 120).

10. The method according to any one of claims 1 to 9, wherein: The first material includes PETG or PC.

11. The method according to any one of claims 1 to 10, wherein: The second material is selected from the group consisting of PETG, PC, PA, PP, ABS and TPE.

12. The method according to any one of claims 1 to 11, wherein: Both the first material and the second material comprise the same polymer material, preferably PETG or PC.

13. The method according to any one of claims 1 to 12, wherein: The third material is selected from the group consisting of TPE, silicone and rubber.

14. The method according to any one of claims 1 to 13, comprising the steps of: At least one side of the window is coated with a layer of a fourth material.

15. A full face mask (1) for an air purifying respirator (APR) or a powered air purifying respirator (PAPR), the full face mask comprising: a viewing window (10, 110) comprising a cut-out of a first transparent polymer sheet (100) that has been formed into a three-dimensional geometric shape; and A frame (20, 120) is formed of a second material that has been injection molded onto a periphery (11, 111) of the viewing window (10, 110).

16. The full face mask according to claim 16, further comprising a face sealing edge (30, 130) which has been injection molded onto the periphery (21, 121) of the frame (20, 120).

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