Face mask improvements

Abstract

The disclosed method of manufacturing a filter mask includes using an overmolding step to both form the seal member and secure the seal member to the support frame and sheet of filter material.

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a facial mask, in particular a facial mask for filtering air, i.e. a filter mask, and to a facial mask manufactured by the disclosed method. [Background technology]

[0002] Face masks that filter particulate matter from the air, or filter masks, typically come in one of two types. Specifically, face masks can have a mask body that itself functions to filter particulate matter from the air. This type of filter mask is typically lightweight and relatively inexpensive for single-use and disposable use. Alternatively, face masks can have a mask body adapted to receive a replaceable filter cartridge so that they are reusable.

[0003] Filter masks can be worn in work or public settings to protect against dust, smoke, and other harmful substances, as well as against pathogens such as viruses or bacteria. For example, in healthcare settings, filter masks are used to prevent inhalation of pathogens from the environment by preventing particulates, such as droplets and aerosols, from passing through the mask. Filter masks can also protect others from pathogens exhaled by the wearer.

[0004] A filter mask typically comprises a filter, such as a sheet of woven or nonwoven filter material, and a means for holding the mask on the wearer's head, for example, by elastic loops placed around the ears. In use, the filter covers the user's mouth and nose or otherwise directs air through the filter, so that all air inhaled by the wearer passes through the filter. To protect others from pathogens exhaled by the wearer, the filter may be positioned so that all air exhaled by the wearer passes through the filter.

[0005] Filtering masks worn in work environments, such as by medical professionals, must remain securely fitted to the face and be comfortable to wear for significant periods of time in environments where the risk of contamination may be high. Such masks must fit snugly against the wearer's face, preferably forming a seal against the face to prevent inhaled and exhaled air from passing around the edges of the mask.

[0006] Filter masks are generally single-use products that are manufactured and sold in large quantities. To make this type of product commercially viable, the cost and complexity of manufacturing must be minimized. Summary of the Invention [Problem to be solved by the invention]

[0007] There has now been developed a facial mask for filtering air and a method of making the same that overcomes or substantially mitigates the above-referenced and / or other problems associated with the prior art. [Means for solving the problem]

[0008] According to a first aspect of the present invention, there is provided a method of manufacturing a filter mask, the filter mask comprising a support frame, a filter, and a seal member, the method comprising: a) placing a filter and a support frame in a mold; b) injecting a polymer material into the mold to form a seal member; The seal member is engaged with the filter and support frame during injection molding of the seal member to secure the seal member to the support frame and sheet of filter material.

[0009] The injection molding of the sealing member in the method according to the invention may be overmolding, which in the context of the present invention means an injection molding process in which a first material is molded onto a second material to form a single article, the first material being able to partially or totally cover the second material.

[0010] The method for manufacturing a filter mask according to the first aspect of the present invention is advantageous primarily because the step of injection molding the seal member secures the seal member to the support frame and the sheet of filter material, thereby fixing the relative positions of these components without the need for any additional assembly or molding steps.Facial masks, particularly filter masks, are mass-produced and low-cost products.Because the profit margins on each individual item are low, reducing the cost and complexity of the manufacturing process is key to producing a viable product.

[0011] According to a further aspect of the present invention there is provided a filter mask manufactured according to the method described above. According to a further aspect of the present invention there is provided a filter mask comprising a support frame, a filter and a seal member, the seal member being secured to the support frame and the filter.

[0012] The support frame and filter together may define a mask body that forms a cavity for accommodating the wearer's mouth and nose. The mask body may be curved in at least the transverse plane.

[0013] The support frame may be fabricated in a preceding step of the method of the present invention. The support frame may be fabricated by injection molding in the preceding step. Thus, the method may further include a preceding step in which the support frame is formed by injection molding. The method may further include a step of transferring the support frame from a first mold in which the support frame is injection molded to a second mold in which the seal member is injection molded.

[0014] The support frame may be made from a plastic material such as polypropylene, poly(styrene-butadiene-styrene) (SBS), polycarbonate, plastomer, thermoplastic, thermoplastic elastomer, thermoset, or blends or combinations thereof.

[0015] The support frame may have an outer surface and an inner surface, the inner surface facing the wearer in use and the outer surface facing away from the wearer in use.

[0016] The support frame can support at least a portion of the filter, for example, by preventing distortion of the sheet of filter material. The support frame can provide rigidity to the mask.

[0017] The support frame can be in the form of a rim, for example, conforming to the shape of the filter material. The rim can have the form of a closed loop. The rim can define an opening through which inhaled and / or exhaled air flows in use. When a filter is placed on the support frame, the support frame can extend around the periphery of the filter. The support frame can include a shoulder extending from an inner edge of the rim, which provides a surface against which the filter can be placed and facilitates retention of the filter within the mold prior to injection molding of the seal member. The filter can be placed on an inner surface of the support frame.

[0018] Instead of or in addition to a rim, the support frame may include one or more ribs, eg, a plurality of ribs, extending across the surface of the filter, eg, to provide support to the filter and rigidity to the mask.

[0019] In a filter mask according to the present invention, the outer surface of the support frame may further comprise a shield extending over at least a portion of the surface of the filter. The shield may be separate from the filter, allowing air to flow between the shield and the filter before being drawn through the filter by the wearer, for example, during inhalation. Thus, a space or void may exist between the shield and the filter. An inlet opening may be defined between an edge of the shield and the surface of the filter through which air can be drawn by the wearer inhaling.

[0020] The shield can provide a barrier against which particles in the environment impinge. Therefore, the shield can reduce the amount of particles that strike the filter during use, thereby extending the useful life of the filter, and therefore the filter mask. The separation between the shield and the filter allows incoming air to flow through the filter across its entire surface, even if the shield is impermeable or substantially impermeable. The shield also provides reinforcement to the mask, preventing it from collapsing longitudinally and keeping the mask positioned correctly against the wearer's nose and chin.

[0021] The shield may be formed from a plastic material, which may form a solid barrier for deflecting particles and may reduce the risk of physical damage to the filter by providing a protective barrier. The shield may form a rigid barrier.

[0022] Alternatively, the shield may be a composite shield formed from two or more components. The composite shield may include a sheet of filter material (shield filter) and a shield frame, with the shield filter overlaid on and attached to the shield frame. The shield frame may be a plastic frame or may form part of the support frame. The shield frame may include a shield rim having substantially the same shape as the intended shield and / or shield filter, with the shield rim attached to the periphery of the shield filter. Such a composite shield can actively absorb and block contaminants and reduce moisture accumulation within the mask, increasing wearer comfort. The composite shield may be removably secured to the mask so that it can be replaced if saturated. Either the entire composite shield or only the sheet of filter material may be removable and replaceable.

[0023] According to a further aspect of the present invention, there is provided a filter mask comprising a support frame, a filter and a seal member, the support frame holding the filter such that ambient air is drawn through the filter upon inhalation by a wearer, the support frame including a shield extending over at least a portion of an outwardly facing surface of the filter, the shield being separate from the filter, and in use, air flowing between the shield and the filter before air is drawn through the filter by the wearer during inhalation.

[0024] According to a further aspect of the present invention, there is provided a filter mask comprising a support frame, a primary filter and a seal member, the support frame holding the primary filter such that upon inhalation by a wearer ambient air is drawn through the primary filter, the support frame including a shield frame carrying the shield filter extending over at least a portion of the outward facing surface of the primary filter, the shield frame being separated from the primary filter such that, in use, air flows between a peripheral edge of the shield frame and the primary filter.

[0025] In the following paragraphs, unless otherwise indicated, references to "shield" refer to both shields formed from plastic material and composite shields formed from a shielding frame and a shielding filter. Additionally, unless otherwise indicated, references to "filter" refer to the main filter, i.e., the filter held by the support frame, and references to "shield filter" refer to the filter that forms part of the composite shield.

[0026] The support frame may include a rim and a shield, or a rim and a shield frame, and the shield or shield frame may be offset from the rim, e.g., in a cross-section. The rim may extend around and / or over the periphery of the filter, and the shield or shield frame may be offset from both the rim and the filter. The rim and shield or shield frame may be connected together by one or more connecting members that extend between the shield and rim and can fix their relative positions. For example, the connecting members may extend between the rim and the shield or shield frame at three, four, or five points, and these points may be regularly spaced around the rim.

[0027] The shield may be offset from the filter, for example in cross section, and may have a shape that corresponds to the shape of the filter, with the surfaces of the filter and shield being parallel.

[0028] When measured along a line perpendicular to the surface of the shield, there may be a gap between the shield and the filter having an average size of 0.1 to 5 cm, or 0.2 to 2.5 cm, or 0.2 to 1.5 cm, or 0.3 to 1 cm. This gap between the shield and the filter may be maintained by one or more ribs extending across at least a portion of the surface of the shield facing the filter. The ribs may be linear or arcuate. The ribs may contact the filter, preventing the shield from contacting the filter material and thus maintaining airflow between the shield and the filter material, even while the wearer is moving.

[0029] The surface area of ​​the shield may be at least 50%, at least 60%, at least 70%, or at least 80%, or at least 90%, or at least 95% of the surface area of ​​the filter. The surface area of ​​the shield may be up to 110%, or up to 105%, or up to 100%, or up to 95% of the surface area of ​​the filter. The shield may extend over at least 50%, at least 60%, at least 70%, or at least 80%, or at least 90%, or at least 95%, or up to 100% of the surface area of ​​the filter.

[0030] The shield may extend across the entire surface area of ​​the filter, or may extend beyond the periphery of the filter so that the shield overhangs the edge of the filter. Alternatively, the shield may extend across less than 100% of the surface area of ​​the filter, such that a portion of the filter is exposed at the periphery of the shield. Alternatively or additionally, the shield may be formed with openings through which the sheet of filter material is exposed, which can aid in airflow and help evenly distribute the particle load on the filter. Alternatively, the shield may have no openings and form a continuous barrier. Thus, the shield may have a continuous surface that extends across most of the surface of the filter material.

[0031] There may be a space between the edge of the shield and the rim of the support frame through which the filter is exposed to the environment, caused by a horizontal offset of the shield from the filter and / or the shield extending over less than 100% of the surface area of ​​the filter. The offset of the shield from the filter and / or partial coverage of the filter by the shield allows air to flow around the shield and through the filter, ensuring that the full surface area of ​​the filter material is used while the wearer is breathing.

[0032] At the same time, the shield itself protects some or most of the filter. The shield can trap some of the airborne particles, such as aerosol particles and / or other contaminants, that contact the mask, preventing them from coming into contact with the filter. This increases the lifespan of the mask by increasing the time it takes for the filter to become saturated. The shield also reduces the risk of damage to the more delicate filter and prevents or blocks the wearer from touching a potentially contaminated filter while handling the mask.

[0033] At least a portion of the periphery of the shield may be separated from the rim of the support frame, thereby defining one or more inlet openings through which air is drawn when the wearer inhales. The one or more inlet openings may be arranged in a loop or partial loop to allow occlusion by the wearer's fingers to perform a fit test. In particular, prior art tests of the fit of face masks on a wearer typically involve expensive testing equipment or are not easily performed by the wearer themselves. Arranging the one or more inlet openings in a loop or partial loop to allow occlusion by the wearer's fingers allows the wearer to then test whether air leaks into the mask when the one or more inlet openings are occluded, thereby testing the fit of the mask. In particular, if the face mask fits effectively, the wearer should not be able to inhale when one or more openings are blocked.

[0034] According to a further aspect of the present invention, there is provided a filter mask comprising a support frame, a filter, and a seal member, the support frame holding the filter such that ambient air is drawn through the filter upon inhalation by a wearer, the filter mask including a shield extending over at least a portion of the outwardly facing surface of the filter, at least a portion of the periphery of the shield being separated from the support frame, and one or more inlet openings defined between the shield and the support frame through which air is drawn upon inhalation by the wearer.

[0035] The separation between the periphery of the shield and the support frame is preferably less than the width of an average human finger, e.g., an index finger, for an adult mask or a child mask. For example, the separation between the periphery of the shield and the support frame may be less than 2 cm, or less than 1.5 cm, or less than 1 cm.

[0036] The one or more entrance openings may be located around the entire periphery of the shield, but may be separated by a member connecting the support frame and the shield. The one or more entrance openings in the nose and / or chin regions may extend along a curved path from an angled apex in the mask's central region outward toward the sides of the mask to accommodate a wearer's fingers during fit testing, with the fingers meeting at the angled apex. Alternatively, or in combination, the one or more entrance openings in the nose and / or chin regions may extend along a regular curved path from one side of the mask to the other to accommodate a wearer's fingers during fit testing, with the fingers meeting at the midpoint of the curved path. The one or more entrance openings in the side regions of the mask may be aligned with the longitudinal axis of the mask and the wearer, i.e., the axis from the nose to the chin region, or may be generally linear in shape to accommodate, for example, a portion of the wearer's hand between the index finger and thumb during fit testing.

[0037] Alternatively, one or more inlet openings may be positioned around a portion of the periphery of the shield. In particular, the inlet openings may be positioned around the cheek and / or chin regions, with no inlet openings in the nose region. This arrangement may direct the exhaled airflow away from the wearer's eyes, increasing wearer comfort and reducing or preventing fogging of the wearer's eyeglasses. This arrangement of openings still allows for the fit testing described in the preceding paragraph to be performed.

[0038] Alternatively, the mask may be provided with covers for one or more inlet openings, which allow the openings to be closed without the wearer having to use their fingers to close the openings.There is therefore also provided a kit of parts comprising a filter mask according to the above-described aspect of the invention and covers for one or more inlet openings, which covers allow the openings to be closed to perform a fit test.

[0039] Further arrangements for facilitating fit testing include means for generating an odor on the mask, which will be filtered out. For example, the mask can include an odor-releasing element on the exterior of the filter and a cover for suppressing the odor prior to use, the cover being at least partially removed, e.g., by peeling, scratching, etc., to at least partially expose the odor-releasing element. The wearer should be unable to detect an odor if the face mask fits effectively.

[0040] According to a further aspect of the present invention, there is provided a filter mask comprising a support frame, a filter and a seal member, the support frame holding the filter such that upon inhalation by a wearer ambient air is drawn through the filter from outside the filter to inside the filter, and the filter mask including an element for releasing odours onto the outside of the filter.

[0041] The filter mask may include a cover for suppressing odors before use, the cover being at least partially removable to at least partially expose the odor-releasing element. The cover can reduce the risk of odors being transferred to other parts of the filter mask, such as the inside of the filter. Furthermore, the cover can be removed once the mask is fitted to ensure that fit testing is not affected by the wearer detecting odors before the test.

[0042] The filter may be sufficiently impermeable to odors so that the wearer does not detect odors in the air drawn through the filter. Elements may be exposed to emit odors only on the exterior of the filter, so that the wearer should not be able to detect odors when the face mask fits effectively.

[0043] The odor-releasing element may comprise or be disposed on a portion of the support frame, such as the shield or a portion of the shield, or the odor-releasing element may be applied to the entire support frame. If the element is applied to the entire support frame, any portion of the support frame on the inside of the filter may need to be covered to suppress odor, for example, by overmolding a thermoplastic elastomer cover.

[0044] The support frame may include a shield extending across at least a portion of the outwardly facing surface of the filter, with at least a portion of the periphery of the shield being separated from the support frame. One or more inlet openings may be defined between the shield and the support frame, through which air is drawn upon inhalation by a wearer.

[0045] The support frame is typically formed from a plastic material that retains its shape during use. The support frame may include a rim and / or a shield and / or one or more connecting members. If multiple components are present, the entire support frame may be integrally formed, for example, by injection molding, or the support frame may be formed of two or more parts that are connected together, for example, by gluing, welding, or mechanical fastening. Thus, if the support frame includes a rim and a shield, the rim and shield may be integrally formed in a single injection molding step, or the rim and shield may be formed separately and then joined together either chemically or mechanically.

[0046] The filter may be formed from a filter substrate that is dense enough to prevent the passage of most airborne particles, such as dust particles, liquid droplets, and aerosols. The masks of the present invention may filter out at least 80%, or at least 85%, or at least 90%, or at least 95%, or at least 99% of airborne particles.

[0047] In countries including the UK and European Union, FFP standards stipulate the requirements for filter masks as respiratory protection devices. The EN149 standard defines three classes of filter efficiency: FFP1, FFP2, and FFP3. The mask of the present invention may be, for example, an FFP3 mask, which, under the EN149 standard, filters out at least 99% of airborne particles at an airflow of 95 L / min and has a total inward leakage of less than 2%. The mask of the present invention may be an FFP2 mask, which filters out at least 94% of airborne particles at an airflow of 95 L / min and has a total inward leakage of less than 8%. In the United States, the National Institute for Occupational Safety and Health (NIOSH) provides the N95 classification for air filtration, and the mask of the present invention may be an N95 mask, which means that it filters out at least 95% of airborne particles.

[0048] Materials suitable for use as filter substrates are known in the art, and any suitable material can be used for the sheet of filter material in the present invention. For example, the filter can be a nonwoven material, an electrostatic material, a meltblown material, a spunbond material, a woven material, a nanofiber material, or a nanoweb material, or can be formed from a glass fiber medium. The filter can include multiple layers to enhance its performance and enhance wearer comfort. Thus, the filter can include one or more layers selected from nonwoven materials, electrostatic materials, meltblown materials, spunbond materials, woven materials, nanoweb materials, and / or nanofiber materials. For example, the filter can include layers of nonwoven materials, electrostatic materials, and meltblown materials, along with a fibrous layer, to enhance wearer comfort and provide structure to the filter. The filter can have any suitable configuration; for example, the surface of the filter can be smooth, e.g., flat or planar, or the filter can be pleated. The filter (pleated or non-pleated) may have flat or planar areas around its periphery to facilitate the overmolding process. The filter may further include one or more additives to enhance its effectiveness in reducing or preventing the transmission of pathogens, such as antimicrobial agents.

[0049] The use of pleated filters increases the filter's surface area, improving its effectiveness. Pleating a filter can increase its surface area by 5 to 50%, or 5 to 30%, or 10 to 20% compared to a non-pleated filter. To accommodate a pleated filter, the shape of the support frame can correspond to the shape of the pleated filter, ensuring a tight fit between the two components to prevent leakage. For example, if the filter abuts a shoulder or rim on the support frame, the shoulder or rim can have a series of corrugations that correspond to the pleats of the filter, so that when the filter contacts the shoulder or rim, the corrugations nest with the pleats of the filter to ensure a tight fit. The filter can be pleated before being placed in a mold with the support frame, and a seal member can be overmolded to secure the seal member, support frame, and filter together. Alternatively, pleats may be formed in the filter by compressing an unpleated (i.e., flat or planar) filter between a corrugated rim or shoulder of the support frame and a correspondingly shaped mold before overmolding the seal member to secure the seal member, support frame, and filter together.

[0050] The filter placed in the mold in the method of the present invention may include only the filter substrate and may be flexible in shape. The filter may not include a support for the filter substrate until secured to the support frame and seal member.

[0051] The filter may be cut to the correct shape from a larger sheet of filter substrate, for example, using a die. If the filter is formed from multiple layers, the filter may be cut to size and the edges may be sealed in a single hot stamping process, in which heat is used to seal the peripheral edges of the filter during the cutting process. The sealed perimeter prevents moisture or contaminants from penetrating into the filter material between the layers during use. The size and shape of the filter may correspond to the size and shape of at least a portion of the support frame. For example, the size and shape of the filter may correspond to the size and shape of the rim of the support frame, so that the filter can be positioned on the rim, for example, on a shoulder extending inward from the rim, such that the support frame extends around the perimeter of the filter.

[0052] In some embodiments, the filter can be contacted with the support frame before the support frame and filter are both placed in the mold. For example, the filter can be placed on the rim of the support frame before the support frame and filter are both placed in the mold. Alternatively, the support frame can be placed in the mold before the filter is positioned on the support frame. In either case, both the support frame and the filter are placed in the mold prior to injection molding of the seal member. Preferably, the support frame and the sheet of filter material are not fastened or bonded together before being placed in the mold.

[0053] The seal member is adapted to fit snugly against the wearer's face and is overmolded around both the filter and the support frame. Thus, the filter and support frame are placed in a mold and their relative positions are fixed by injection molding of the seal member. This secures the support frame, filter, and seal member together in a single step without the need for additional adhesives or overmolding steps, thereby reducing time and cost.

[0054] To secure the filter and support frame together in a single overmolding step, the filter can be positioned on an outer or inner surface, such as a rim, of the support frame such that the edges of the sheet of filter material and the support structure are substantially aligned. During injection of the polymer material that forms the seal member, a portion of the polymer material can encase the aligned edges of the sheet of filter material and the support structure. Thus, the peripheral edges of both the filter and the support frame, or the rim of the support frame, can be encapsulated within the portion of the polymer material that forms the seal member.

[0055] Alternatively, during overmolding of the seal, the injected material may be directed between the filter and the support frame such that it forms an adhesive layer between the filter and the support frame around the periphery of the filter. The periphery of the filter may be enveloped by the injected material, which then bonds to the support frame (e.g., to the rim of the support frame). The injected material may be absorbed into the filter around the periphery of the filter, strengthening the bond between the seal and the filter and providing additional protection against moisture ingress between the layers of filter material.

[0056] By "substantially aligned" it is meant that the edges of the filter material and the support structure are positioned close enough together that they can be enveloped by a portion of the seal member or otherwise adhered together.

[0057] The seal member may be formed from an elastomeric material, and materials suitable for use in making seal members for face masks are known in the art. For example, the seal member may be formed from a thermoplastic elastomer (TPE) or a thermoset elastomer, such as liquid silicone rubber.

[0058] The sealing member may be shaped to fit snugly against the wearer's face and seal against the face so that all air inhaled by the wearer passes through the filter material. To enhance comfort and sealing, the sealing member may be in the form of a cushion. That is, the sealing member may form a resiliently compressible area between the support frame and the wearer's face to enhance comfort and improve the seal.

[0059] Because mask effectiveness improves with improved fit (and reduced leakage), it is useful to have a mask that can adapt to different sized faces and remain effective even when the wearer moves and takes an active role, such as the filtering masks used by medical professionals.

[0060] Any embodiment of the support frame and / or seal may include one or more additives to help enhance the effectiveness of the mask in reducing or preventing the spread of bacteria or other pathogens. In particular, additives containing silver ions (e.g., in the form of Silver Knight™) may be incorporated into the plastic of the support frame and / or seal. Silver ions have been found to catalyze the inactivation of pathogenic bacteria, preventing their proliferation and reducing microbial growth within and on the surface of the mask.

[0061] According to a further aspect of the present invention, there is provided a filtering mask comprising a support frame and a sheet of filtering material, the support frame and the sheet of filtering material defining a mask body adapted to provide a cavity around a wearer's mouth and nose in use, the filtering mask including a seal member depending from at least a portion of a peripheral edge of the mask body, the seal member comprising a lip portion depending both inwardly and outwardly relative to the peripheral edge of the mask body.

[0062] The seal member may extend around the entire peripheral edge of the mask body. A portion of the peripheral edge of the support frame around which the inwardly and outwardly depending lip portions extend may constitute a chin portion. The inwardly depending lip portion may extend around most of the peripheral edge of the support frame. The outwardly depending lip portion may extend around only a portion of the peripheral edge of the support frame, for example, in the chin region.

[0063] The inwardly depending lip portion may be in a generally flat configuration. The inwardly depending lip portion may be in the form of an upstanding wall that follows the contour of the peripheral edge of the body. The inwardly depending lip portion may include a discontinuity that facilitates deformation of the inwardly depending lip portion.

[0064] The outwardly depending lip portion may have a concave contact surface. The outwardly depending lip portion may be shaped to provide a base or shelf formation under the wearer's chin. A proximal portion of the outwardly depending lip portion may engage the wearer's chin, while a distal portion may curve and extend under the wearer's chin. The outwardly depending lip portion may be shaped in the form of a chin cup. The chin cup may accommodate at least a portion of the wearer's chin in use. The outwardly depending lip portion may be shaped to provide both a front lip portion and a lower lip portion.

[0065] The inwardly depending lip portion may contact the lower part of the wearer's face, such as the wearer's chin, to form a seal. For users with larger facial heights, the outwardly depending lip portion may pass just below the wearer's lower chin to provide an additional seal. For all wearers, the outwardly depending lip portion provides an alignment guide for positioning the mask on the face and can help keep the mask in the correct position on the face even if the chin moves during use.

[0066] The periphery of the support frame near the inner and outer lip portions may be shaped by a first radius from a center point or region of the mask. The inwardly depending lip portion typically has an inner edge with a radius smaller than the first radius. The outwardly depending lip portion typically has an outer edge with a radius larger than the first radius.

[0067] The nose portion of the seal member may include an inwardly depending lip portion and may present a convex surface for contact with the wearer's face. The nose portion of the seal member may include reinforcing formations, e.g., portions of increased thickness, on each side of the nose, and may have a reduced thickness, e.g., in the nasal bridge region.

[0068] The seal member, and therefore the filtering mask, may also extend laterally across the wearer's cheeks such that a seal is formed between the mask seal and cheek tissue and the interior cavity of the mask extends across the cheeks.

[0069] During speech, the majority of facial movement is within the jaw, including the vertical separation of the nose and chin, while there is a relatively small amount of movement in the cheeks. Additionally, cheek tissue is softer and more compliant than either the nose or chin tissue. This means that a lesser degree of flexibility is required for the sealing member to achieve an effective seal with the cheek tissue than in other parts of the face.

[0070] According to a further aspect of the present invention, there is provided a face mask comprising a mask body defining a cavity for accommodating a wearer's nose and mouth, through which, in use, a wearer inhales respiratory gases, and a sealing member depending from the mask body for engagement with the wearer's face, the mask body comprising a nose portion for accommodating the wearer's nose, a mouth portion for accommodating the wearer's mouth, and cheek portions extending laterally across the wearer's cheeks.

[0071] The cheek portions may extend laterally across the wearer's cheeks between the upper edges of the wearer's cheekbones and the lower edge of the wearer's chin.

[0072] The cheek portions may each have a first edge extending from the left or right edge of the nose portion, such that the first edge of the cheek portion rests on the wearer's cheekbones. The first edge may extend along an arcuate path. The first edge may be a concave outer edge. The transition between the first edge of the cheek portion and the left or right edge of the nose portion may be arcuate.

[0073] The cheek portions may each have a second edge extending from the left or right edge of the mouth portion, such that the second edge of the cheek portion is received above the lower edge of the wearer's chin. The second edge may extend along an arcuate path. The second edge may be a concave outer edge. The transition between the second edge of the cheek portion and the left or right edge of the mouth portion may be arcuate.

[0074] The angle between the first and second edges of each cheek portion may increase with increasing lateral position, and the first and second edges may be substantially parallel at the distal ends of the cheek portions, e.g., at positions adjacent the wearer's ears. The edges of each cheek portion may be substantially straight. The distal region of each cheek portion may be substantially rectangular in shape, thereby increasing the surface area of ​​the mask body covering the wearer's cheeks.

[0075] The mask body may extend a greater distance transversely across the wearer's face relative to the distance the mask body extends longitudinally across the wearer's face. The greater distance may be relative to the surface of the wearer's face, i.e., the distance may be a dimension along the surface of the face as opposed to a linear dimension.

[0076] The mask body may extend a greater distance in the transverse direction relative to the distance the mask body extends longitudinally. The greater distance may be relative to the surface of the mask, i.e., the distance may be a dimension along or parallel to the surface of the mask, as opposed to a linear dimension.

[0077] The portion of the mask body that accommodates the wearer's nose and mouth may have an outer surface that is, for example, generally arcuate in cross section, while the portion that accommodates the wearer's cheeks may have an outer surface that is, for example, substantially flatter in cross section. The filter mask and its internal cavity may extend laterally across the wearer's cheeks so that the edges of the mask are located within 5 cm, or 4 cm, or 3 cm, or 2 cm of the wearer's ears when in use. Thus, the mask can substantially cover the wearer's cheeks.

[0078] If the facial mask is a filter mask, the mask body may be defined by a support frame and a filter. The seal member may extend around a periphery of the support frame, for example, around a rim. The shape of at least a portion of the support frame and the filter may correspond to the shape of a proximal edge of the seal member. The support frame and the filter may extend laterally across the cheeks of the wearer.

[0079] The mask body of the facial mask may extend laterally across the cheeks of the wearer. The seal members of the facial mask may extend laterally across the cheeks of the wearer. The portion of the mask body extending across the cheeks of the wearer may form a shallower cavity between the mask and the wearer's face than the portion of the mask extending over the wearer's nose and mouth.

[0080] The extension of the mask over the cheeks increases the surface area of ​​the sheet of filter material and therefore the volume of air that can pass through the filter. At the same time, the shallower cavity in this area of ​​the mask reduces dead space within the mask.

[0081] A filtering mask according to the invention may include means for securing the mask to a wearer in use. Such means may include one or more cords or straps, for example elastic cords or straps, that fit around the wearer's head to press the filtering mask against the wearer's face.

[0082] The cord or strap may be formed as a separate component or components and then inserted through holes or slots and attached to the filtering mask by knotting or sealing, or by bonding the cord or strap to the mask. The cord or strap may be bonded to the mask by adhesive or chemical bonding, or by overmolding. The cord(s) or strap(s) may be worn over the wearer's ears or around the back of the wearer's head. This may help prevent the mask from slipping and / or riding up on the wearer's face during use.

[0083] Two cords or straps may be provided, passing around each of the wearer's ears, or one cord passing over the wearer's ears and one passing under the ears and running around the back of the head.

[0084] Alternatively, a single cord may pass twice across the back of the wearer's head. A first side of the support structure may be positioned adjacent one of the wearer's ears in use, and a second side of the support structure may be positioned adjacent the other of the wearer's ears in use. The first and second sides of the support structure may be located in areas of the support structure closest to the wearer's ears in use.

[0085] The two ends of a single elastic cord or strap may be held by a pair of first attachment formations located on a first side of the support frame, for example, the side adjacent one of the wearer's ears. The first attachment formations may be integrally formed with the support frame or may be formed separately and then attached, for example, by gluing, welding, or mechanical fastening (e.g., snap-fit ​​fastening). Each of the pair of first attachment formations may hold one end of the cord or strap and may be a clip or clamp, or an opening or slot through which the cord or strap can be threaded, with a knot tied to the cord or strap to prevent it from slipping back through the slot or opening.

[0086] At least one, e.g., one or two, attachment formations may be located on a second side of the support frame, e.g., the side adjacent the other of the wearer's ears, the attachment formation(s) holding a central portion of the cord or strap. Thus, the cord or strap may extend from one of the first attachment formations through the second attachment formation(s), form a cord loop, and return to the other of the first attachment formations.

[0087] This configuration can allow a user to tighten the cord or strap by pulling the loop formed in the second attachment formation(s), thereby providing an improved tightening configuration that may be beneficial for other types of face masks.

[0088] According to a further aspect of the present invention, there is provided a facial mask comprising a pair of first attachment formations and a pair of second attachment formations, the pair of first attachment formations being positioned on a first side of the facial mask near a first ear of a wearer in use, the pair of second attachment formations being positioned on a second side of the facial mask near a second ear of the wearer in use, each of the pair of first attachment formations providing means for securing an end of a strap, and the pair of second attachment formations providing means for releasably securing an intermediate portion of the strap.

[0089] A pair of second attachment formations may be disposed on a second side of the support frame, and the cord or strap may be passed sequentially through the pair of second attachment formations to form a loop of the cord between the pair of second attachment formations. The second attachment formations may allow easy passage of the cord in one direction upon application of tension, but may offer significant resistance to movement of the cord in the opposite direction without additional user action (e.g., pressing a button or applying significantly greater force). Thus, while wearing the mask, the wearer can easily adjust the length of the strap to fit their head size with one hand by pulling the loop of the cord formed between the pair of second attachment formations. When tension is applied, the cord will slide through the pair of second attachment formations, thus shortening the length of the cord around the back of the wearer's head and pressing the face mask against the wearer's face. Once the fit is correct, the user releases the cord, and the mask is held in place by the cord or strap.

[0090] The pair of second attachment formations may each comprise a slot or opening substantially covered by the tab. An edge of the tab and / or the corresponding edge of the slot or opening may comprise a means for gripping the cord, such as a roughened surface or a series of teeth. In use, the cord or strap is inserted through the slot or opening between the edge of the tab and the edge of the slot or opening. A gripping formation, such as a series of teeth or a roughened surface along at least one edge of the tab or along the slot / opening and the corresponding edge of the tab, can prevent the cord or elastic from slipping back through the slot or opening. The series of teeth may be angled or curved outward, i.e., in a direction in which easy movement of the cord through the slot or opening is desired. Thus, the teeth may be angled or curved away from the slot or opening so that when the cord or strap moves in the opposite direction, the teeth will embed into and promote gripping of the cord or strap.

[0091] Alternatively, the pair of second attachment formations may each include a slot or opening and an elastic member, the elastic member substantially covering the slot and elastically biased against the slot. In use, a cord or strap is inserted through the slot against the bias of the elastic member, such that tension applied to the strap pulls the elastic member sufficiently away from the slot or opening to allow the cord to pass through the slot or opening. When tension on the cord is released, the bias of the elastic member pushes the elastic member back against the slot or opening, closing it and trapping the cord between the elastic member and the edge of the slot or opening. Thus, the cord can be easily pulled through the slot by application of tension against the bias of the elastic member, but the elastic member can prevent the cord from inadvertently moving in the opposite direction through the slot, even when tension is applied to the cord (e.g., when the cord is stretched around the wearer's head). A means for releasing the biased member may be provided to allow the cord to slide in the reverse direction through the slot when desired by the wearer, for example a release catch, or reverse movement may be activated when a significant force is applied by the wearer. The elastic member may further comprise means for gripping the cord, for example a rough surface or a series of teeth, to help prevent slippage of the cord.

[0092] The first and / or second attachment formations may form part of the support frame. The first and / or second attachment formations may be integrally formed with the support frame. The second attachment formation may be integrally formed with the support member in a single molding step. Thus, a tab extending planarly across the opening may be integrally formed within the support frame in a single molding step. The tab may protrude from the support frame. Due to manufacturing limitations, flashing may cause the tab to be attached to the opening in an undesirable position, where the distance between the edge of the tab and the adjacent edge of the opening is small, e.g., less than 2 mm, or less than 1 mm, or less than 0.5 mm. This can be resolved by applying a force to the tab to break the flashing. The force may be applied to a surface of the tab, e.g., a surface of the tab protruding from the support frame. Such a force may be applied to the tab using an overmolding tool during the overmolding step to form the seal member, thus reducing the number of separate steps required in the manufacture of the mask.

[0093] Accordingly, there is provided a method of integrally forming a tab extending planarly across an aperture such that a distance between at least one edge of the tab and at least one adjacent edge of the aperture is less than 2 mm, the method comprising: a) using injection molding to form a tab extending planarly across the aperture such that a distance between at least one edge of the tab and at least one adjacent edge of the aperture is less than 2 mm; b) applying a force to a surface of the tab to release flashing formed between the at least one edge of the tab and the at least one adjacent edge of the opening during the injection molding process.

[0094] When used in the manufacture of filter masks, the injection molding process in step a) above can also form the support frame, and the application of force in step b) above can be performed by designing the shape of the overmold tool used to manufacture the seal member such that pressure is applied to the tabs to break the flashing when the mold is closed on the support member prior to overmolding. Thus, this process can be used to integrally form the second attachment formation of the filter masks described herein without requiring an additional manufacturing step.

[0095] Alternatively, the first and / or second attachment formations may be formed separately from the support frame and then connected to the support frame by chemical or mechanical means.

[0096] The mask may include an opening in the filter, which may provide a conduit through the filter or may include or be adapted to receive an additional device, such as an exhalation valve. The opening may bypass the filter material. The opening in the filter material may be attached and / or sealed to an opening in the support frame or to a device attached to the support frame. Furthermore, the polymer material injected into the mold to form the seal member may engage with the filter and the opening in the support frame or to a device attached to the support frame during injection molding of the seal member to seal the filter around the opening or device.

[0097] The mask may include one or more vents or valves, such as exhalation valves. Exhalation valves allow exhaled air to escape the filter mask without passing through the filter, thus reducing heat and humidity retained by the filter during use. However, including an exhalation valve may not be desirable when the filter mask is needed to protect others from pathogens exhaled by the wearer, for example, in a medical environment. The vents or valves may be located in the shield or in the rim of the support frame. The valve may be inserted into an opening in the shield or rim, or may form part of the shield or rim. If the valve is inserted into or forms part of the shield, the valve may also extend through the filter material, and an overmolding step to form a seal member may be used to additionally provide a seal between the valve and the filter material and / or between the opening in the support frame for receiving the valve and the filter material. If the valve is inserted into or forms part of the rim, a portion of the rim may be molded to accommodate the valve, for example, in the chin area.

[0098] If a valve is included, the injection molding step for forming the sealing member can also form the valve member. Thus, the sealing member and the valve member may be integrally formed. After molding the sealing member / exhalation valve, the valve may be inserted through the openings in the filter and shield, or through the opening in the rim. Tension between the valve and the surrounding material (shield, filter, or rim) biases the valve to close. This allows exhaled air to flow from the inside to the outside of the mask, but prevents air from flowing in the opposite direction.

[0099] The support frame, e.g., the shield and / or filter, can have an opening formed therein through which either the releasable cover or the exhalation valve can fit. An overmolding step to form a seal member can be used to additionally provide a seal between the opening in the support frame for receiving the valve or cover and the filter material. For example, the releasable cover can be secured over the opening using a snap-fit ​​or screw-fit connection, and the cover can be removed and replaced with an exhalation valve as needed. This allows for the manufacture of a single mask that can be used with or without an exhalation valve. The size of the opening is appropriate for the installation of an exhalation valve and can be 10-50 mm in diameter, 15-40 mm in diameter, or 15-30 mm in diameter. Typically, the opening diameter is approximately 20 mm.

[0100] The filtering mask may further comprise a stopcock that can be used to connect the mask to tubing for introducing or removing gas from the mask and / or wearer. Thus, the filtering mask may be used as an oxygen delivery mask or respirator, with the added protection that inhaled air (other than the oxygen being delivered) must pass through a filter. In the same manner as an exhalation valve, the stopcock may be releasably attached to an opening in the shield and, optionally, the filter. The opening may be sized to accommodate a stopcock having a diameter of 10-50 mm, or 15-40 mm, or 15-30 mm. Alternatively, the opening may be sized to accommodate a stopcock having a diameter of 2-10 mm, or 2-8 mm, or 4-8 mm. Alternatively, the stopcock may be integrally formed with the shield or another portion of the support frame.

[0101] Alternatively, the filter mask may not include a plug. Such a filter mask would be unsuitable for use as an oxygen delivery mask or respirator. Additionally or alternatively, the filter mask may include an access port. For example, the filter mask may include an access port for an endoscope, nasal cannula, or high-flow nasal cannula, allowing an endoscopy to be performed or a cannula to be worn while still providing the patient and physician with the protection provided by the filter mask. Medication or oxygen may be delivered through a high-flow nasal cannula; a characteristic of this type of treatment is that aerosolized particles may be generated and released into the environment. Depending on the nature of the patient's illness, such aerosolized particles may become contaminated and pose a risk to nearby personnel. Allowing access to the airway for delivery of the high-flow nasal cannula while wearing a filter mask to contain any generated aerosols provides a safer environment for clinicians and other nearby personnel. The access port may include an opening in the filter mask. The opening may include a pair of openings in a support frame, e.g., a shield, and a sheet of filter material, aligned with each other, allowing the cannula to pass through both openings. An overmolding step to form a seal member may be used to additionally provide a seal between the opening in the support frame and the filter material. The openings in the support frame, shield, and / or filter material may be provided with removable covers to cover the openings when not in use.

[0102] Alternatively, the face mask may be configured so that the sheet of filter material is replaceable, meaning that the entire mask does not need to be replaced after use, but only the filter material needs to be replaced, while the mask frame, including the support structure and seal, can be reused multiple times, thereby reducing both cost and waste.

[0103] A mask with a replaceable filter according to this embodiment can be manufactured using the same principles as described above in a method involving a single overmolding step that fixes the relative positions of the support frame and seal.

[0104] According to a further aspect of the present invention, there is provided a method of manufacturing a filtering mask, the filtering mask comprising a support frame and a seal member, the support frame having a housing for receiving a filter, the method comprising: a) providing a support frame within the mold; b) injecting a polymeric material into a mold to form a first seal member for sealing against the face of a wearer and a second seal member for sealing against a filter received by the housing; The seal member is engaged with the support frame to secure the seal member to the support frame during injection molding of the seal member.

[0105] According to a further aspect of the present invention, there is provided a filtering mask manufactured according to the method described above. Also provided is a filtering mask comprising a support frame and a seal member, the support frame further comprising a housing for receiving a filter, the seal member being secured to the support frame. Any of the features described above in relation to the filtering mask of the present invention may be present in this embodiment, including, but not limited to, a shield, and / or first and second attachment formations, and / or a seal member comprising inwardly and outwardly depending lip portions, and / or the inclusion of a valve or access port.

[0106] The filter may comprise only the filter substrate, which may be releasably attachable to the support frame by any suitable means, for example by clips, or by an interference fit, or by a releasable adhesive, for example an adhesive strip covered by a peelable liner that is removed immediately prior to insertion of the sheet of filter material.

[0107] Alternatively, the filter may comprise a filter substrate held in a cartridge or other support connectable to the support frame. For example, the cartridge may be connected to the outer surface of the support frame by one or more snap-fit ​​connectors or clips, or by friction fit, or there may be a port provided in the support frame to accommodate the cartridge. In this embodiment, if the mask comprises a shield, the shield may form part of the cartridge or other support such that the shield is positioned on the outer surface of the filter when the cartridge is attached to the outer surface of the mask (i.e., the cartridge or other support may comprise the shield). Alternatively, the shield may be hingedly attached to the support frame, and may be openable to allow insertion of the filter cartridge adjacent to the outer surface of the support frame and then closed. The filter cartridge may be held in place by one or more clips or other attachment members, or a hingedly attached shield may hold the filter cartridge in place.

[0108] Alternatively, the filter cartridge is connected to the inner surface of the support frame by one or more snap-fit ​​connectors or clips. In this embodiment, the shield (if present) may be present as shown in the drawings and as described above. For example, the filter mask may include a shield that, in use, extends across at least a portion of the outward-facing surface of the filter, with at least a portion of the periphery of the shield being separate from the support frame, and / or may be integrally formed with the support frame.

[0109] The cartridge may take the form of a plastic, e.g., injection-molded plastic, rim that conforms to the shape and size of the filter substrate and is secured around the periphery of the filter substrate, so that the cartridge does not restrict the flow of air through the filter substrate.

[0110] It will be understood that any feature described in relation to one aspect of the invention may be applied to any other aspect of the invention. Thus, any structural feature described in relation to a mask with an integrated filter, such as a shield, first and second attachment formations, an exhalation valve, and / or a bung, may be applied to a mask with a replaceable filter as described above.

[0111] Embodiments of the present invention will now be described, by way of example only, with reference to the following drawings, in which: [Brief explanation of the drawings]

[0112] [Figure 1] 1 is a perspective view of a support frame in a first embodiment of a filter mask according to the present invention; FIG. [Figure 2] FIG. 3 is a side view of the support frame of FIG. 2. [Figure 3] 1 is a perspective view of a filter in a first embodiment of a filter mask according to the present invention. FIG. [Figure 4a] 1 is a perspective view of a filter positioned within a support frame in a first embodiment of a filter mask according to the invention during manufacture. FIG. [Figure 4b] FIG. 4a without the filter. [Figure 5] 5 is a perspective view of the support frame and filter of FIG. 4 and a mold core used during the manufacture of a first embodiment of a filter mask according to the present invention. [Figure 6] 1 is a side view of a first embodiment of a filtering mask according to the present invention; FIG. [Figure 7] 1 is a perspective view of the rear of a first embodiment of a filtering mask according to the present invention; FIG. [Figure 8] 10 is a schematic diagram showing the connection between the support frame and the filter material formed by overmolding the seal member. FIG. [Figure 9a] 10A-10C are front and rear perspective views of a second embodiment of a filtering mask according to the present invention. [Figure 9b] 10A-10C are front and rear perspective views of a second embodiment of a filtering mask according to the present invention. [Figure 10a] 10A-10C are front and rear perspective views of a third embodiment of a filtering mask according to the present invention. [Figure 10b] 10A-10C are front and rear perspective views of a third embodiment of a filtering mask according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0113] A support frame 10 for use in a filter mask according to the present invention is shown in Figures 1 and 2. The support frame 10 has a generally curved shape and includes an integrally formed rim 11, a shield 12, a pair of first attachment formations 13, and a pair of second attachment formations 14. The shield 12 is substantially the same shape as the rim 11, but is smaller and offset from the rim 11 by approximately 1 cm. The shield 12 is attached to the rim 11 by four connecting members 16 evenly spaced around the rim's circumference, attaching to points near the edge of the shield. A space 15 between the shield 12 and the rim 11 extends around the periphery of the shield and is interrupted only by the connecting members 16. The support structure 10 is an integrally formed component, with all features manufactured in a single injection molding step.

[0114] A pair of first attachment formations 13 extend outward from a first side of the rim 11, which in use is located near a first ear of the wearer. The first attachment formations 13 take the form of keyhole-shaped slots through which a cord or strap (not shown) can be threaded and secured with a knot or clamping device. A pair of second attachment formations 14 extend outward from a second side of the rim, which in use is located near a second ear of the wearer. The second attachment formations 14 include a slot (not visible) covered by a tab 17. The tab 17 has a series of teeth 18 that provide grip. The cord or strap (not shown) passes through the slot in the attachment formations 14 from the inside to the outside of the support frame between the tab 17 and the edge of the slot. The teeth 18 grip the cord and reduce or prevent reverse movement of the cord.

[0115] In use, the cord or strap is secured to the upper first attachment formation 13, passes through the upper second attachment formation 14 from inside to outside, passes through the lower second attachment formation 14 from outside to inside, and finally is secured to the lower first attachment formation 13. The strap thus passes behind the wearer's head twice, forming a loop between a pair of second attachment formations 14 on the outside of the support structure. When the wearer applies tension to the loop, for example, by pulling on the loop, the cord is pulled through the opening and passes through the teeth 18 on the tab 17. When this tension is released, for example, by the wearer releasing the cord loop, the teeth 18 are able to grip the cord, thus preventing it from slipping back through the slot unless significant force is applied. In this way, the mask can be easily adjusted to fit the wearer's head with one hand.

[0116] Injection molding is used to manufacture the support frame 10, which is a one-piece unit manufactured from injection molded polypropylene in a single step.

[0117] When filter mask manufacturing is automated, the support frame 10 is ejected from the mold onto a vacuum cup on a robotic arm. A pneumatic die forces a sheet of filter material 22 from a roll of filter material into the support frame 10, where the roll of filter material contains a continuous series of pre-stamped sheets of filter material that are heat-sealed around their peripheral edges. A sheet of filter material 22 is shown in FIG. 3.

[0118] The sheet of filter material is placed on the inside of the support frame 10, i.e., on the side of the support frame 10 that will face the wearer in use. The sheet of filter material is placed on inwardly extending shoulders and is held in place around its periphery by retention tabs 19 on either side of the rim. This support structure / filter material assembly is shown in Figures 4a and 4b.

[0119] The support structure / filter material assembly is transferred into a first half of a mold and mounted on a mold core 30. The second half of the mold is sealed to the first half of the mold to form a mold cavity. In an injection molding step, a seal member 25 is overmolded onto the support structure / filter material assembly, surrounding the periphery of the sheet of filter material 22 and adhering it to the support frame 10 in a single overmolding step to form the seal member 25. The filter mask 20 is removed from the mold using, for example, a 20 mm pin to peel the filter mask 20 from the core 30 and transferred for manual attachment of an elastic cord and subsequent packaging.

[0120] The connection between the filter, seal member, and support frame is shown schematically in FIG. 8 . The periphery of the filter 91 is positioned against a shoulder 94 extending laterally from the rim of the support frame 93, either before or after the support frame 93 is placed in the mold. Thermoplastic elastomer (TPE) 92 is injected into the mold to form the seal member. The portion of the TPE 92 shown in FIG. 8 represents only the proximal edge of the seal member. The TPE 92 is forced by the mold between the peripheral edge of the filter 91 and the rims and shoulders of the support frames 93, 94. The TPE 92 surrounds and impregnates the peripheral edge of the filter 91, and the impregnated area of ​​the periphery, designated 95, is bonded to the rims and shoulders of the support frames 93, 94. As shown in FIG. 8 , a tool shutout prevents the TPE 92 from entering the filter 91 beyond the periphery 95, ensuring that the filtering action of the filter 91 is not inhibited by the TPE. In addition to assisting in adhering the support frames 93, 94 to the filter, the impregnation of the peripheral edge 95 of the filter 91 with TPE contributes to the seal at the edges of the filter formed by heat sealing, which can prevent moisture or other contaminants from penetrating into the structure of the filter.

[0121] A side view of a filtering mask 20 according to the present invention is shown in Figure 6. The support structure 21 is the same as that described in connection with Figures 1 and 2. A sheet of filtering material 22 is positioned behind the support structure 21 and is visible around the periphery of the shield 23 in the gap between the shield 23 and the rim 24. This allows air to easily flow past the shield 23 and through the filtering material 22 while still benefiting from the protection of the shield over the filtering material.

[0122] The seal member 25 is overmolded onto the support frame 21 and the filter material 22 to secure their relative positions. The seal member 25 includes a chin engaging portion 26, a nose engaging portion 27, and a cheek engaging portion 28. The cheek engaging portion 28 extends laterally across the cheeks to form a seal against the softer skin on the cheeks, improving the overall seal of the mask.

[0123] The seal member 25 is formed of an elastomeric material, thereby providing a compressible area between the support structure 21 and the wearer's face, allowing the elastomeric material to conform to the contours of the wearer's face and provide a good seal thereagainst.

[0124] 4a and 4b show a support structure / filter element assembly with and without the presence of filter material, respectively. The support structure 10 includes a rim 11 having an inwardly extending shoulder 18 upon which a pre-cut sheet of filter material 22 is placed. Extending from a first side of the rim is a first mounting formation 13, and a second mounting formation 14 extends from a second side of the rim. The support frame 10 also includes a shield 12. A series of vertical ribs 29 across the rear of the shield 12 ensure that spacing between the shield 12 and the filter material 22 is maintained.

[0125] A second embodiment of a filter mask according to the present invention can be seen in Figures 9a and 9b and is generally designated 100. The structure of the mask is substantially the same as that described in connection with the first embodiment shown in Figures 6 and 7, except that the mask 100 further comprises a mushroom valve 101 (shown in the closed position). In the chin area, a rim 102 of a support frame comprises an upwardly protruding portion 103, and the shapes of the shield 104 and the filter material 105 correspond to the shape of the inner periphery of the rim 102 so that they accommodate the upwardly protruding portion 103. The filter material 105 is sealed along the periphery of the rim 102 of the support frame, including the upwardly protruding portion 103, by a peripheral rim of TPE 106. The upwardly protruding portion comprises an opening, and the mushroom valve 101 is formed within the opening as part of an overmolding step that also forms the seal member 107. The mushroom valve 101 allows exhaled air to escape without passing through the filter material 105. Alternatively, the mushroom valve 101 can be housed within a shield 104 .

[0126] A third embodiment of a filtering mask shown in Figures 10a and 10b is generally designated 110 and has substantially the same structure as that described in the second embodiment in connection with Figures 9a and 9b, but instead of the mushroom valve, it shows an elbow connection 111. The elbow connection 111 allows the mask 110 to be connected to other medical devices such as a nebulizer.

Claims

1. 1. A method of manufacturing a filter mask comprising a support frame, a filter, and a seal member, comprising: a) placing the filter and the support frame in a mold; b) injecting a polymer material into the mold to form the seal member; 1. A method of manufacturing a filter mask, wherein the seal member is engaged with the filter and the support frame so as to secure the seal member to the support frame and the filter during injection molding of the seal member, and so as to fix the relative positions of the support frame and the filter by injection molding the seal member.

2. 10. The method of manufacturing a filter mask according to claim 1, wherein the support frame is made by injection molding in a previous step of the method, and the method further comprises the step of transferring the support frame from a first mold in which the support frame is injection molded to a second mold in which the seal member is injection molded.

3. 3. The method of claim 1 or 2, wherein the support frame extends around the periphery of the filter when the filter is placed in the mold with the support frame.

4. A method of manufacturing a filter mask according to any one of claims 1 to 3, wherein the support frame comprises a rim that, in use, defines an opening through which inhaled and / or exhaled air flows.

5. 5. The method of manufacturing a filter mask according to claim 4, wherein the support frame includes a shoulder extending from an inner edge of the rim to provide a surface against which the filter can be placed to facilitate retention of the filter within the mold prior to injection molding of the seal member.

6. 6. A method of manufacturing a filter mask according to claim 4 or 5, wherein the filter is placed on the support frame before the support frame and the filter are both placed in the mould.

7. 7. A method of manufacturing a filter mask according to any one of claims 1 to 6, wherein the support frame comprises one or more ribs extending across the surface of the filter to provide support to the filter and rigidity to the filter mask.

8. The method for manufacturing a filter mask according to any one of claims 1 to 7, wherein the filter placed in the mold in the manufacturing method comprises only a filter substrate.

9. A method of manufacturing a filter mask according to any one of claims 1 to 8, wherein the support frame and the filter are not fixed or bonded together prior to injection moulding of the seal member.

10. A method for manufacturing a filter mask according to any one of claims 1 to 9, wherein during injection moulding of the seal member, a portion of the seal member adheres aligned edges of the filter and the support frame.

11. A method for manufacturing a filter mask described in any one of claims 1 to 10, wherein during injection molding of the sealing member, the injected material forms an adhesive layer between the filter and the support frame.

12. A filter mask comprising a support frame, a filter, and a seal member, wherein the seal member is fixed to the support frame and the filter, and the relative positions of the support frame and the filter are fixed by injection molding of the seal member.

13. 13. The filtering mask of claim 12, wherein the support frame and the filter together define a mask body that forms a cavity for accommodating a wearer's mouth and nose.

14. 14. The filtering mask of claim 12 or 13, wherein the outer surface of the support frame comprises a shield that extends over at least a portion of the surface of the filter.

15. 15. The filtering mask of claim 14, wherein the shield is separate from the filter to allow air to flow between the shield and the filter before air is drawn through the filter by the wearer during inhalation.

16. 16. The filtering mask of claim 14 or claim 15, wherein one or more inlet openings are defined between an edge of the shield and the support frame through which a wearer can draw air by inhaling.

Images