Disposable face mask with enhanced fluid barrier

Abstract: A disposable face mask (10) that includes a filter body (14) capable of filtering liquids and/or particles of a size appropriate for the mask's (10) intended purposes, while providing excellent breathability and comfort to the wearer for extended periods of time. The filter body (14) is formed from multiple layers of filtration material having various configurations. Such masks (10) may be secured by one or more knitted headbands (16,18) to the head of a wearer. Various gasket-type sealing materials such as plastic film or other materials such as hydrogel may be used to enhance the fluid barrier formed between the periphery (24,38) of the mask (10) and the wearer's face.

Description: This invention relates generally to disposable face masks capable of preventing the passage of airborne aerosols, particulate matter and/or liquids. More particularly, this invention relates to disposable face masks having an enhanced fluid barrier between the periphery of the mask and a wearer's face. Also, this invention allows using various materials to enhance the filtration capabilities of the resulting mask for the specific operating environment while maintaining good breathability. Disposable face masks have been manufactured for many years. In the medical field, many of these early masks were used in preventing contamination of a patient by the breath of health care personnel. In recent years with increased concern for infection of health care personnel with airborne pathogens, such as the hepatitis B virus, it has become necessary to not only prevent contamination of patients due to exhalation from health care personnel, but also to prevent infection of health care personnel due to inhalation of airborne infection particles. It has become even more important in view of the advent of human immunodeficiency virus (HIV) and the recent increase in infectious tuberculosis associated with many HIV patients. The rapid increase of infectious diseases, particularly AIDS, has made the use of such protective equipment increasingly important. The Center for Disease Control in Atlanta, Georgia, has found that the AIDS virus (HIV) can be passed by contact with body fluids. Contact of AIDS contaminated body fluids with another person's source of body fluids, e.g., eyes, nose, mouth, etc., can pass the disease. Therefore, it is necessary to prevent a patient's body fluids from contacting the face of health care personnel. Aerosols having airborne liquid and solid particles are generated not only by the exhalation of infected patients, but also by certain procedural manipulations and processes that impart energy to any liquid or microbial suspension. Surgical procedures involving use of drills and saws are particularly prolific producers of aerosols which may contain tuberculosis, HIV or other pathogens from an infected patient. Concern with tuberculosis has been increasing since new strains of the disease show strong resistances to multiple types of drug treatment. One type of mask is illustrated in U.S. Patent No. 2,012,505 entitled Mask, issued on August 27, 1935 to S.J. Goldsmith. Another type of disposable face mask is illustrated in U.S. Patent No. 4,319,567 entitled Disposable Face Mask , issued on March 16, 1982 to M. Magidson. This mask is molded and has been especially configured in an effort to avoid leakage of fluid flow past the edges of the mask. Obviously, leakage cannot be tolerated when attempting to control liquids and/or aerosols. U.S. Patent 4,606,341 entitled Noncollapsible Surgical Face Mask, issued August 19, 1986 to Vance M. Hubbard and Welton K. Brunson shows a conventional rectangular face mask having a trapezoidal pleat. For some operating conditions, rectangularly shaped masks, including the mask shown in Patent '341, may have less than an optimal fit to prevent the passage of liquids and aerosols between the periphery of the masks and a wearer's face. Recent developments in surgical face masks have resulted in resistance to liquid penetration from the exterior of such masks. US Patent No. 4,920,960 entitled Body Fluids Barrier Mask, issued on May 1, 1990 to Hubbard, et al., is exemplary of improvements in such masks. US Patent No. 5,020,533 entitled Face Mask with Liquid and Glare Resistant Visor, issued on June 4, 1991 to Hubbard, et al ., is an example of incorporating a visor to protect the face of a wearer from liquids during medical procedures. FR-A-2,249,643 discloses a disposable face mask in accordance with the precharacterising portion of claim 1. US-A-4,616,647 discloses a molded fiber disposable face mask having enhanced nose and chin filter-seals. US-A-4,790,307 discloses a disposable surgical mask having a self-contained supply of anti-bacterial material. US-A-5,419,318 discloses a breathing mask comprising a soft, flexible face-contacting member of cup shape and an outer shell member fastened thereto. In accordance with the present invention, there is provided a disposable face mask comprising: a filter body sized to fit over the mouth and nose of a wearer, the filter body having top and bottom edges with the top edge arranged to extend across the nose and cheeks of the wearer and the bottom edge arranged to extend under the chin of the wearer; a first strip of sealing material disposed on the interior of the filter body adjacent to and extending along the top edge; a second strip of sealing material disposed on the interior of the filter body adjacent to and extending along the bottom edge; a flap attached to each side of the filter body; and first securing means and second securing means attached to the respective flaps and arranged to extend about the head of the wearer, the first and second securing means cooperating with the flaps for urging the first strip of sealing material on the top edge and the second strip of sealing material on the bottom edge into tight engagement with the wearer to prevent undesired fluid flow between the top edge and the bottom edge and the wearer's face; the flaps cooperating with their respective first securing means and second securing means to prevent undesired fluid flow between the respective sides of the filter body and the face of the wearer; characterised in that the flaps extend laterally outwards from the sides of the filter body and the first and second securing means are attached to the flaps so as to be laterally outwards of the sides of the filter body. A disposable face mask incorporating the present invention provides an enhanced fluid barrier around the periphery of the mask to prevent the bypass of both liquids and aerosols between the edges of the mask and the wearer's face. For some applications the disposable face mask may include one or more layers of selected materials such as expanded polytetrafluoroethylene to enhance the filtration capability of the resulting mask. The present invention may be applied to standard pleated style face masks or off-the-face style masks. For some applications, a single pair of ties may be used to secure the mask to the head and face of the wearer. For other applications, the mask may be secured to the head and face of the wearer with four surgical tie strips or a continuous loop of resilient material. The flaps extend the coverage area of the face mask and improve the fluid seal in cooperation with the sealing material between the periphery of the mask and the face of the wearer. The securing means may be formed from resilient material to provide comfort to the wearer while maintaining a tight peripheral seal for long periods of time. The securing means may be formed from various types of material as desired. Embodiments of the invention provide significant technical advantages by forming a barrier which prevents the passage of liquids and aerosols between the periphery of the mask and the wearer's face. The resulting face mask blocks liquid spray and aerosols from passing through the exterior of the mask or around the edges of the face mask and contacting portions of the wearer's face. Further technical advantages of an embodiment of the invention include the use of a filter media formed from expanded polytetrafluoroethylene (PTFE) membrane with one or more layers of bicomponent polyethylene or polypropylene disposed on opposite sides of the filter media. The seals may be formed by thin layers of plastic film materials such as polyethylene and polypropylene. For other applications, various types of hydrogel may be disposed on the periphery of the face mask as the sealing material. By forming a gasket-type seal with the sealing material, normal movement of the face mask associated with breathing and talking by the wearer will not compromise the fluid barrier formed between the sealing material and the wearer's face. For a more complete understanding of the present invention and advantages thereof, reference is now made to the following description of exemplary non-limiting embodiments of the invention taken in conjunction with the accompanying drawings, in which: FIGURE 1 is a perspective view of a disposable face mask incorporating an embodiment of the present invention illustrated on the head of a wearer; FIGURE 2 is a front plan view of the mask shown in FIGURE 1; FIGURE 3 is a back plan view of the mask shown in FIGURE 1; and FIGURE 4 is a back plan view of a face mask incorporating a further embodiment of the present invention. The preferred embodiments of the present invention and its advantages are best understood by referring to FIGURES 1-4 of the drawings, like numerals being used for like and corresponding parts of the various drawings. For purposes of this application aerosols are defined as insoluble liquids or particulate matter frequently associated with microbial solutions. The term "fluid" is used within this application to include any gas, liquid, or mixture of gas and liquid. Various types of particulate matter and aerosols may be entrained with such fluids. For purposes of this application, the term "gasket-type seal" means a fluid barrier or pressure tight seal formed by placing a deformable material between two relatively stationary objects. Such gasket-type seals are sometimes referred to as "static seals". A wide variety of gasket-type sealing materials including thin plastic films and/or hydrogels may be satisfactorily used to form a gasket-type seal between the periphery of a face mask and the face of a wearer. Other types of deformable material such as open cell and closed cell foams may also be used to form the desired gasket-type seal. Mask 210 incorporating an embodiment of the present invention is shown in FIGURES 1, 2 and 3. Mask 210 includes filter body 228 with flaps 230 and 232 extending respectively from each side of filter body 228. As will be explained later in more detail, strips 270 and 272 of gasket-type sealing material are disposed respectively adjacent to top edge 244 and bottom edge 246. For some applications, filter body 228 may be fabricated in general as described in U.S. Patent 4,635,628 entitled Surgical Face Mask with Improved Moisture Barrier and U.S. Patent 4,969,457 entitled Body Fluids Barrier Mask. Flaps 230 and 232 are preferably formed from fluid impervious material folded with a generally U-shaped cross section. Flaps 230 and 232 may sometimes be referred to as C-folds. For one application of the present invention, flaps 230 and 232 may be formed from polyethylene film laminated to a non-woven material. The non-woven material may also be hydro- entangled. For other applications, the polyethylene film may be laminated to any type of material as desired. The polyethylene film layer may be color coded to correspond with different applications for using the resulting face mask. For still other applications, a breathable type film may be used to form flaps 230 and 232. For further applications, flaps 230 and 232 may be formed from resilient and/or stretchable materials. Such resilient materials include thermoplastic rubbers which may be extruded or injection molded as strips or sheets of material. An example of such thermoplastic rubbers is available under the trademark KRATON® from Shell Oil Company. One of the benefits of an embodiment of the invention is the ability to form flaps 230 and 232 from materials that have lower cost as compared to the material used to form filter body 228. Another benefit of an embodiment of the invention is the ability to form strips 270 and 272 along with flaps 230 and 232 from a wide variety of materials which provide an enhanced fluid seal with the face of the wearer while providing a comfortable fit during long periods of wear. Such materials are available from various suppliers. Filter body 228, flaps 230 and 232, and strips 270 and 272 are designed to prevent the undesired flow of liquids from the exterior of mask 210 to the face of wearer 212. It is extremely difficult to construct a mask that will fit the facial configuration of all wearers without constructing the mask specifically for each individual face. The use of strips 270 and 272 along with flaps 230 and 232 greatly increases the different sizes and types of faces which can be effectively protected by mask 210. Forming flaps 230 and 232 from suitable resilient or stretchable material further improves facial fit with a large number of wearers. Filter body 228 may comprise a plurality of pleats 233, 234 and 235 which allow expansion of filter body 228 to cover the mouth and nose of wearer 212. The number of pleats 233, 234 and 235 formed in filter body 228 may be varied to provide the desired fit with the face of wearer 212. Pleat 233 is preferably folded in a reverse direction as compared to pleats 234 and 235. By providing reverse pleat 233, filter body 228 has an increased tendency to stand away from the face of wearer 212. For some applications filter body 228 may be formed without pleats. For other applications, filter body 228 may be formed with non-collapsing face panels such as shown in U.S. Patent 4,606,341 entitled Non-Collapsible Surgical Face Mask. For still further applications, filter body 228 may be formed from only one layer of material or from multiple layers of material. Flaps 230 and 232 allow for a wide variety of options in selecting material with the desired breathability and fluid resistance for filter body 228. The use of reverse pleat 233 in cooperation with pleats 234 and 235 forms a larger breathing chamber as compared to other soft, pleated style masks which contact a substantial portion of the wearer's face. The larger breathing chamber permits cooler and easier breathing associated with "off-the-face" style mask such as shown in U.S. Patent 4,606,341. The present invention allows optimizing the volume of air contained within filter body 228 without sacrificing comfort to the wearer or filtration efficiency. Various adhesives, ultrasonic seals and/or heat seals may be used to attach strips 270 and 272 on the interior of filter body 228 respectively adjacent to top edge 244 and bottom edge 246. A plurality of ultrasonic seals (sometimes referred to as ultrasonic welds) 244a and 246a respectively have been found to be particularly advantageous for respectively attaching strips 270 and 272. If the breathing chamber formed by filter body 228 is too large, excessive amounts of exhaled air may be retained within filter body 228 at normal breathing rates. By properly selecting the size of filter body 228 and flaps 230 and 232, excessive heating of air within filter body 228 is minimized and dizziness from prolonged periods of re-breathing exhaled air is also minimized. Since the present invention results in an enhanced fluid seal or barrier formed in part by strips 270 and 272 between the periphery of mask 210 and the face of wearer 212, incorporating the benefits of an "off-the-face" style face mask is important for extended periods of wearing mask 210. As shown by the cutaway portion of FIGURE 2, filter body 228 includes four layers of material with an external surface of cover stock 236 as the outermost layer. Inner layer or internal surface 238 which contacts the face of wearer 212 may be constructed of a light weight, highly porous, softened, non-irritating, non-woven fabric, such as Dexter, Inc. product No. 3768. Inner layer 238 is designed to prevent unwanted materials such as facial hair, loose fibers or perspiration from contacting intermediate layers 240 and 242 which might cause a wicking effect to draw liquids through filter body 228. Inner layer 238 also provides a comfortable surface for contact with the face of wearer 212. Intermediate layer 240 preferably comprises a barrier material that is capable of differentiating between gases and liquids and may be, for example, Visqueen Film Products' low density polyethylene, Vispore X-6212. Non-wetting materials, such as used to form barrier material 240, have small apertures which prevent liquids with a relatively high surface tension from passing therethrough yet will allow gases with a low surface tension to pass therethrough. It is preferable to have the apertures as large as possible to allow easy breathing, and yet small enough to retard or prevent the flow of liquids. Intermediate layer 240 is designed to freely pass gases in either direction, while restricting the passage of liquids in at least one direction. Filter body 228 is constructed with barrier material 240 positioned to restrict liquid passage from the exterior of mask 210. Further description of the construction and operation of such barrier material may be found in U.S. Patent No. 3,929,135 issued December 230, 1975, to Thompson, assigned to Procter and Gamble Co. The next intermediate layer is preferably filtration media 242, which may be, for example, melt blown polypropylene or polyester. Filtration media 242 is provided to inhibit the passage of airborne bacteria in either direction which will prevent passage of germs to and from wearer 212. Outermost layer 236 provides the external surface for filter body 228, which may be treated, for example, by spraying with a liquid repellant to render the external surface material resistant to liquids. Outer layer 236 and filtration media layer 242 serve as an aid to barrier material 240 by slowing down any liquid that may be splashed, sprayed or thrown at mask 210. By requiring the liquid to pass through layers 236 and 242 prior to reaching barrier material 240, the liquid will have less pressure and barrier material 240 will be better able to prevent passage of the liquid. Outer layer 236 may be formed from non-woven material such as cellulose fiber. Filter body 228 may be formed by bonding layers 236, 238, 240, and 242 with each other in a generally rectangular configuration. Such bonding is preferably provided along top edge 244, bottom edge 246 and lateral sides 250 and 252, respectively. The corresponding bonded areas 244a, 252a, 246a, and 250a may be formed by sewing, glue, heat sealing, welding, ultrasonic bonding and/or any other suitable bonding procedure. Flaps 230 and 232 are preferably integrally attached to filter body 228 as part of the respective bonded areas 250a and 252a. Flaps 230 and 232 are preferably formed from fluid impervious material such as a plastic membrane and folded with a U-shaped configuration to form an opening to receive tie strips 216 and 218 therein. Bonded areas 220 and 222 are preferably used to secure the approximate mid-point of tie strips 216 and 218 with corresponding mid-points of flaps 230 and 232. Top edge 244 of filter body 228 preferably includes an elongated malleable member 248 provided so that top edge 244 of filter body 228 can be configured to closely fit the contours of the nose and cheeks of wearer 212. Malleable member 248 is preferably constructed from an aluminum strip with a rectangular cross section, but may also be a molded or malleable-steel or plastic member. Top edge 244, bottom edge 246 and flaps 230 and 232 cooperate with each other to define the periphery of mask 210 which contacts the face of wearer 212. Strips 270 and 272 along with flaps 230 and 232 substantially increase the area of contact with the face of wearer 212 as compared to a face mask having only top edge 242, bottom edge 246 and lateral sides 250 and 252 in contact the face of wearer 212. Typically surgical style pleated face masks have a generally rectangular or square configuration of approximately 17.8 x 17.8 cm (7 x 7 inches) prior to pleating. The length and width dimensions of a typical face mask may vary by ± 1.27 cm (½ inches) resulting in a face mask which is often rectangular in configuration as compared to a square. For some applications, the present invention allows reducing the length of top edge 244 from 17.8 cm (7 inches) to as short as 11.4 to 12.7 cm (4½ to 5 inches). Alternatively, the present invention allows increasing the length of top edge 244 as desired. Also, the distance from top edge 244 to bottom edge 246 when mask 210 has been placed over the face of wearer 212 may be reduced from 17.8 cm to 14.0 to 15.2 cm (7 to 5½ to 6 inches). Therefore, flaps 230 and 232, along with other features of the present invention, allow reducing the total area of the filter media associated with mask 210 from approximately 316 cm 2 (49 square inches) to 161 cm 2 to 194 cm 2 (25 square inches to 30 square inches) while maintaining approximately the same effective area. This reduction in area results in a substantial saving in the cost of materials used to fabricate mask 210 while, at the same time, maintaining good breathability, high efficiency filtration, and providing an improved seal between the periphery of mask 210 and the face of wearer 212 by incorporating strips 270 and 272. The arrangement of surgical ties 216 and 218 is such that portions 216a and 218a extending from top edge 244 may be placed over the top of the head of wearer 212. Portions 216b and 218b extending from bottom edge 246 may be positioned around the lower base of the head of wearer 212 as illustrated in FIGURE 1. Positioning tie strips 216 and 218 in this manner results in compressing or gathering the respective flaps 230 and 232 to form a flat, flange type fluid barrier with the face of wearer 212. Also, securing surgical ties 216 and 218 in this manner urges strips 270 and 272 of gasket-type sealing material disposed respectively along top edge 244 and bottom edge 246 into fluid sealing engagement with the contours of the face of wearer 212. Surgical tie strips 216a, 218a, 216b and 218b may be positioned on the head of wearer 212 to provide the optimum full angle and the optimum amount of force to form the desired fluid barrier between the periphery of mask 210 and the face of wearer 212. Top edge 244 with malleable member 248 conforms very closely to the configuration of the nose and cheeks of wearer 212. It is important that bottom edge 246 and the chin of wearer 212 and top edge 244 and the nose and cheeks of wearer 212 fit very closely since any leaks result in bypass or blow-by of fluids either entering mask 210 or being discharged from mask 210 during use by wearer 212. For some applications, filter body 228 may include outer mask layer 236 that is preferably constructed from a spun-bonded polypropylene. Outer mask layer 236 may also be constructed from a bi-component and/or powder bonded material such as polyethylene or polypropylene, a cellulastic tissue, or a spun-bonded polyester. Outer mask layer 236 will typically-have a basis weight range of 15.5 g/m (0.5 ounces per yard) to 31 g/m (1.0 ounces per yard). 21.7 g/m (0.7 ounces per yard) is one of the preferred basis weights for outer layer 236. Inner mask layer 238 may alternatively comprise bicomponent polyethylene and polypropylene or bicomponent polyethylene and polyester. Layer 238 may also be constructed from polyester and/or polyethylene material or cellulastic tissue. Layer 238 will typically have a basis weight range of 12.4 g/m (0.4 ounce per yard) to 23.3 g/m (0.75 ounces per yard). 12.8 g/m (0.413 ounces per yard) is one of the preferred basis weights for layer 238. One or more intermediate layers of filter media may be disposed between outer mask layer 236 and inner mask layer 238. Selection of the number and type of intermediate layers of filter media will depend upon the intended use and function for mask 210. In FIGURE 2, filter body 228 is shown with only two intermediate mask layers 240 and 242 which comprise the filter media for mask 210. These layers may be constructed from melt-blown polypropylene, extruded polycarbonate, melt-blown polyester, or melt-blown urethane. Various types of material may be used for intermediate mask layers 240 and 242. For example, intermediate mask layer 240 may be formed from an expanded polytetrafluoroethylene (PTFE) membrane. Such materials are manufactured by W. L. Gore & Associates. A more complete description of the construction and operation of such materials can be found in U.S. Patent No. 3,953,566 entitled Process for Producing Porous Products, issued on April 27, 1976 to Robert W. Gore, and U.S. Patent No. 4,187,390 entitled Porous Products for Process Therefor, issued on February 5, 1980 to Richard W. Gore. The present invention allows designing mask 210 with the optimum periphery to fit the face of wearer 212, the optimum dimensions for malleable strip 248 to form an enhanced fluid barrier with the nose and face of wearer 212. The present invention allows modification to the length of top edge 244 and bottom edge 246 while maintaining the required surface area for efficient filtration and normal breathing through filter media 240. The use of barrier materials which block the passage of liquids is particularly important when mask 212 is worn in an environment where wearer 212 may be exposed to "body fluids." These fluids such as blood, urine and saliva may contain highly contagious germs and viruses. Contact of AIDS-contaminated body fluids with another person's source of body fluids, such as the eyes, nose and mouth, may transmit the disease. Therefore, it is often preferable to include layer 240 and/or 242 which are resistant to the passage of liquids through filter body 228 to prevent body fluids from contacting the nose and mouth of wearer 212. Various types of securing means may be used to attach a mask incorporating the present invention to the face of a wearer. Tie strips 216 and 218 shown in FIGURES 1-3 represent one of these alternative securing means. Tie strips 216 and 218 may be replaced by a continuous loop of resilient material which is disposed within but not bonded to flaps 230 and 232. Surgical ties 216 and 218 may be formed from various types of material. For one application of the present invention surgical ties 216 and 218 are preferably formed from thermally bonded polypropylene having a basis weight of 50.9 to 55.9 g/m 2 (1.5 to 1.65 ounces per square yard). This particular type of material can be ultrasonically welded, stitched or heat and pressure bonded in various patterns to provide a resilient securing means for use in attaching mask 210 to the face of wearer 212. As shown in FIGURES 2and3, a single sonic stitch 224 is provided along the length of each surgical tie 216 and 218 to provide the desired longitudinal stretch and recovery capability. Single sonic stitch pattern 224 allows most of the material used to form surgical ties 216 and 218 to be open and free from the associated bonded area. Stitch pattern 224 allows surgical ties 216 and 218 to retain their naturally resilient characteristics. By providing resilient surgical ties 216 and 218, the periphery of face mask 210 will maintain a tight fluid barrier with the face of wearer 212 over a relatively long period of time. Talking and other activities by wearer 212 will not compromise the integrity of the resulting fluid barrier. Laminated strips of material may also be used to form ties 216 and 218. Mask 310 incorporating another embodiment of the present invention is shown in FIGURE 4. Except for the addition of strips 274 and 276 of gasket-type sealing material, mask 310 is essentially the same as previously described mask 210. Strips 274 and 276 may be formed from the same gasket-type sealing material as strips 270 and 272. Strip 276 extends laterally along side 252 of filter body 228 between top edge 244 and bottom edge 246. In a similar manner, strip 276 extends laterally between top edge 244 and bottom edge 246 along side 250 of filter body 228. Only a portion of each strip 270, 272, 274 and 276 is preferably bonded with the interior of face mask 310 to provide flexibility between strips 270, 272, 274 and 276 and filter body 228. Strips 270, 272, 274 and 276 cooperate with each other to allow limited movement of filter body 228 during normal talking and/or breathing of wearer 212 without compromising the fluid barrier formed between the periphery of mask 310 and the face of wearer 212. For some applications it may be desirable to apply suitable hydrogel-type materials and/or other biocompatible adhesive compounds to strips 270 and 272 for mask 210 and strips 270, 272, 274, and 276 for mask 310. For other applications strips 270, 272, and 274 and/or 276 may be eliminated from their respective face masks 210 and 310 and replaced by applying a layer of hydrogel or adhesive to the top edge, the bottom edge, and/or lateral rider of the respective face mask. It may be desirable to apply hydrogel to lateral sides 250 and 252 on the interior surface of mask 210. Examples of hydrogel type materials and compounds satisfactory for use with the present invention are shown in U.S. Patent 5,306,504 entitled Skin Adhesive Hydrogel, Its Preparation and Uses; U.S. Patent 5,254,338 entitled External Application Base or Auxiliary Agent and External Application Composition for Human Being or Animal Containing the Same ; and U.S. Patent 5,183,664 entitled Thin Film at EC Dressings, Preparation and Use . These three patents are representative of only a few of the many types of hydrogel materials and compounds which may be satisfactorily used with the present invention. In addition to the previously discussed materials, face masks 210 and 310 may be manufactured using a wide variety of non-woven materials and/or microporous films. The teachings of the present invention allow incorporating new, state of the art materials into face masks 210 and 310.

Claims: A disposable face mask (210, 310) comprising: a filter body (228) sized to fit over the mouth and nose of a wearer (212), the filter body having top and bottom edges (244, 246) with the top edge (244) arranged to extend across the nose and cheeks of the wearer and the bottom edge (246) arranged to extend under the chin of the wearer; a first strip (270) of sealing material disposed on the interior of the filter body (228) adjacent to and extending along the top edge (244); a second strip (272) of sealing material disposed on the interior of the filter body (228) adjacent to and extending along the bottom edge (246); a flap (230, 232) attached to each side (250, 252) of the filter body (228); and first securing means (216) and second securing means (218) attached to the respective flaps (230, 232) and arranged to extend about the head of the wearer (212), the first and second securing means (216, 218) cooperating with the flaps (230, 232) for urging the first strip (270) of sealing material on the top edge (244) and the second strip of sealing material (272) on the bottom edge (246) into tight engagement with the wearer to prevent undesired fluid flow between the top edge (244) and the bottom edge (246) and the wearer's face; the flaps (230, 232) cooperating with their respective first securing means (216) and second securing means (218) to prevent undesired fluid flow between the respective sides (250, 252) of the filter body (228) and the face of the wearer (212); characterized in that the flaps (230, 232) extend laterally outwards from the sides (250, 252) of the filter body (228) and the first and second securing means (216, 218) are attached to the flaps (230, 232) so as to be laterally outwards of the sides (250, 252) of the filter body (228). The mask of Claim 1, wherein the first strip of sealing material (270) and the second strip of sealing material (272) each comprise a thin layer of plastic film with a portion of the first strip of material and a portion of the second strip of sealing material extending respectively from the top edge (244) and the bottom edge (246) of the filter body (228). The mask of Claim 1 or Claim 2, further comprising an elongate malleable member (248) located in the top edge (244) for conforming the top edge to the contours of the wearer's nose and cheeks. The mask of any preceding claim, wherein the first strip of sealing material (270) and the second strip of sealing material (272) comprise hydrogel. The mask of any preceding claim, wherein the filter body (228) comprises a layer (242) of filter media for restricting the flow of liquids through the filter body. The mask of any preceding claim, wherein the filter body (228) comprises an intermediate layer (240) of filter media formed from expanded polytetrafluoroethylene (PTFE). The mask of Claim 6, wherein the filter body (228) comprises a first layer (236) of bicomponent material disposed on one side of the intermediate layer (240) of expanded polytetrafluoroethylene and a second layer (238) of the same bicomponent material disposed on the opposite side of the layer (240) of expanded . polytetrafluoroethylene.

Inventors: BRUNSON KEVIN K, RASBERRY FRANK D, RICH ALBERT R JR, BRUNSON, KEVIN K., RASBERRY, FRANK D., RICH, ALBERT R. JR.
Applicants: KIMBERLY CLARK CO, KIMBERLEY-CLARK WORLDWIDE, INC.
Application year: 1996
Main classification: A41D13
IPC codes: A41D13