Patent Description:
Face masks are commonly used in the health care industry to reduce the risk of transferring infectious bacteria, virus and the like between the health care practitioners and the patients. Recently, face masks are becoming more widely used by the general public to control, reduce or prevent spreading of respiratory viruses like influenza, SARS, SARS-CoV-<NUM>, and COVID-<NUM>, or at least to serve as precautionary measures. Most face masks work by covering a wearer's face, and more particularly, nose and mouth of the wearer thereby blocking or filtering airborne droplets or aerosols which carry the harmful germs. Various types and designs of face masks, including disposable surgical masks and reusable face covers have been developed, which can be formed with different materials having different filtration efficacies applicable for different uses and purposes. Nonetheless, there exists a need for face masks that provide a more effective barrier to air-borne contaminants while still providing an improved comfortability and usability for the wearers.

For example, <CIT> discloses an air-pollution face mask comprising a filter segment comprising a multi-layered filtration material adapted to cover the mouth and nostrils of the user. The filter segment is joined by a seam with a support segment. The face mask further comprises one or more exhalation valves located at the filter segment. <CIT> discloses a fabric for use in hygienic products such as marks. The fabric comprises a textile material layer composed of microfibers and an inorganic porous substance, and a nanofiber nonwoven fabric layer laminated on the textile material layer. <CIT> discloses an imitative denim fabric for avoiding the generation of electrostatic charges. The imitative denim fabric comprises a base cloth layer having metal electrical conductivity fiber inside a spandex wrapped yarn as the weft yarn. <CIT> discloses a face mask comprising a surface layer, a lining and a functional layer; the functional layer comprises a first fiber layer, a silver-loaded short fiber non-woven fabric layer, a silver-loaded filament filter layer, a high efficiency filter layer and a second fiber layer from outside to inside. The first fiber layer and the second fiber layer are each composed of linen cloth, cotton cloth or blended cloth; the silver-loaded short fiber non-woven fabric layer is composed of polypropylene fiber or terylene non-woven fabric with a layer of nano-silver on the surface of the non-woven fabric; the silver-loaded filament filter layer is composed of multiple filaments, the filaments are hollow polyester filaments with nano-silver is impregnated at the hollow cavity of each filament; the high efficiency filter layer is composed of polypropylene ultra-thin fiber with the surface of the polypropylene ultra-thin fiber being coated with teflon. <CIT> discloses a multilayered fiber filter sheet formed by layering a silver-ion containing sheet with another sheet formed by weaving of bamboo fiber. <CIT> discloses a sterilization mask comprises a sterilization layer having nano silver fibers, a first filtration layer, a second filtration layer and an outer surface layer.

An object of the present invention is to provide a novel material for use in a face mask.

Another object of the present invention is to provide a novel reusable face mask.

A further object of the present invention is to mitigate or obviate to some degree one or more problems associated with known face masks, or at least to provide a useful alternative.

The above objects are met by the combination of features of the main claims. The dependent claims disclose further advantageous embodiments of the invention.

One skilled in the art will derive from the following description other objects of the invention. Therefore, the foregoing statements of object are not exhaustive and serve merely to illustrate some of the many objects of the present invention.

In a first main aspect, the invention provides a composite material for use in a face mask. The composite material comprises a fabric layer comprising a metallic silver-coated fiber material; wherein the metallic silver-coated fibre material is woven into the fabric layer and comprises about <NUM>% to about <NUM>% by weight in respect of a total weight of the fabric layer; and a polymer layer comprising thermoplastic polyurethane (TPU); wherein the fabric layer and the polymer layer are laminated to form a single composite layer; the single composite layer extends substantially an entire area of a face covering portion of the face mask; wherein the fabric layer and the polymer layer are of substantially the same shape and size to overlay each other, such that any air stream passing through the single composite layer of the face covering portion will be effectively filtered by both the fabric layer and the polymer layer.

In a second main aspect, the invention provides a face mask. The face mask comprises a face covering portion formed of the composite material according to the first aspect, and a strap attached to the face covering portion.

The summary of the invention does not necessarily disclose all the features essential for defining the invention; the invention may reside in a sub-combination of the disclosed features.

The foregoing and further features of the present invention will be apparent from the following description of preferred embodiments which are provided by way of example only in connection with the accompanying figures, of which:.

The following description is of preferred embodiments by way of example only and without limitation to the combination of features necessary for carrying the invention into effect.

Reference in this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Similarly, various requirements are described which may be requirements for some embodiments but not other embodiments.

In the claims hereof, any element expressed as a means for performing a specified function is intended to encompass any way of performing that function. The invention as defined by such claims resides in the fact that the functionalities provided by the various recited means are combined and brought together in the manner which the claims call for. It is thus regarded that any means that can provide those functionalities are equivalent to those shown herein.

The present invention relates to a face mask and particularly, a reusable face mask which provides a close-fitting coverage around the wearer's nose, mouth and optionally chin to thereby minimize or eliminate the amount of air-borne contaminants, such as virus, bacteria or the like, from being exhaled and/or inhaled by the wearer. The face mask provides a dual protection functionality, comprising a self-disinfecting layer as well as an effective filtration layer. The reusable face mask further allows good breathability i.e. moisture vapor transmission, with the face mask being reusable and the anti-microbial and filtration efficiencies maintained after about <NUM>-<NUM> times of washings.

<FIG> shows a traditional reusable face mask <NUM> in the prior art. The face mask <NUM> comprises a mask body <NUM> for covering the face, and particularly, the nose and mouth of the wearer. The mask body <NUM> generally comprises one or more layers of fabrics such as, but are not limited to, cotton, silk, and/or other natural or synthetic fiber materials. Very often the face mask <NUM> is provided with an elastic strap <NUM>, which can be a head strap or ear straps affixed to or sewn at the two lateral sides of the mask body <NUM>. The face mask <NUM> may further be provided with a nose clip <NUM> at an upper edge of the mask body <NUM> for positioning of the mask at, and for providing a closer fitting of the mask against the wearer's face.

As the filtration efficiency of the general fabric material is known to be limited, a filter layer <NUM>, which is often provided as a rectangular sheet of porous materials such as microfibers, can optionally be inserted between the mask body <NUM> of the face mask <NUM> and the wearer's face to enhance the filtration effect. However, the filter layer <NUM> will unavoidably be movable within the face mask <NUM> due to movement of the wearer, which significantly reduces the overall filtration efficacy.

Some other face masks are therefore provided with an internal pocket or compartment for accommodating the filter layer <NUM> to keep the filter layer <NUM> in place. Nonetheless, movement of the filter layer <NUM> within the compartment may cause the filter layer <NUM> to become partially folded over within the compartment, which will adversely affect not only the filtration ability of the mask but also the user's comfort of wearing the mask.

Referring to <FIG>, shown is an embodiment of a reusable face mask <NUM> according to the present invention. The reusable face mask <NUM> comprises a face covering portion <NUM> for covering the wearer's face and more particularly, the nose, mouth and optionally the chin of the wearer. In one embodiment, the face covering portion <NUM> is preferably configured in a substantially three-dimensional shape to generally conform with a shape of the nose of the wearer for closer fitting against the wearer's face. The face mask <NUM> further comprises a pair of elastic or resilient ear straps <NUM>, such as the ear loops as shown in the figure, which can be sewn or affixed to the face covering portion <NUM> of the face mask <NUM>. A person skilled in the relevant art will appreciate that any other known types of tying means, such as head ties, elastic bands, straps or the like, will also be applicable, as it is only necessary that the face mask <NUM> is provided with some suitable means of retaining the face mask <NUM> over a wearer's face.

Particularly, the face covering portion <NUM> of the face mask <NUM> is formed of a composite material comprising at least one fabric layer <NUM> having a metallic fiber material namely a metallic silver-coated fibre material; and at least one polymer layer <NUM> laminated with the at least one fabric layer <NUM> to form a single composite layer. More particularly, the at least one polymer layer <NUM> is of substantially the same shape and size as the at least one fabric layer <NUM> such that the two layers substantially overlay each other, whereby any air stream passing through the composite layer will be effectively filtered by both the at least one fabric layer <NUM> and the at least one polymer layer <NUM>.

In one embodiment, the at least one fabric layer <NUM> preferably comprises a first fabric layer <NUM> and a second fabric layer <NUM> configured to sandwich the at least one polymer layer <NUM> therebetween, as shown in <FIG>, with the three layers being laminated to form a single composite layer.

The at least one fabric layer <NUM>, such as either one or both of the fabric layers <NUM>, <NUM>, comprises a metallic silver-coated fibre material such as a metallic silver-coated yarn material. More preferably, the metallic silver-coated fibre or yarn material comprises <NUM>% pure silver metal coated polymer fibre, such as but is not limited to, a polyamide fibre. In one embodiment, the metallic silver-coated yarn material can be woven with one or more other fibre materials, such as one or more non-metallic fibre or yarn materials to form the at least one fabric layer <NUM>. In one embodiment, the one or more non-metallic fibre materials may comprise synthetic fibre materials such as one or more of a polyester fibre or yarn material and a spandex fibre or yarn material. For example, in one specific embodiment, the at least one fabric layer <NUM> can be a woven piece of fabric comprising about <NUM>% to about <NUM>% by weight of the polyester fibre or yarn materials, about <NUM>% to about <NUM>% by weight of the spandex fibre or yarn material, and about <NUM>% to about <NUM>% by weight of the metallic silver-coated fibre or yarn material, although a skilled person will appreciate that the fabric layer <NUM> could also be formed by weaving the metallic silver-coated fibre or yarn with any other known fibres or yarns to thereby vary, adjust or customize the physical and/or chemical properties of the fabric layer <NUM> for different applications and purposes of the face mask <NUM>.

In one embodiment, the at least one fabric layer <NUM>, such as each of the first fabric layer <NUM> and the second fabric layer <NUM> is preferably of a thickness ranged from about <NUM> to about <NUM>.

The metallic silver-coated fibre or yarn material of the fabric layer <NUM> comprises metallic silver atoms, which can be oxidized to form silver ions. These silver ions are known to possess powerful anti-viral and anti-microbial abilities. Particularly, the positively charged metal ions are electrostatically attracted to the negatively charged bacteria, interfering or altering structure of the bacterial DNA and thus inhibiting replication of the bacteria. Metallic silver has also been proven to exhibit inhibiting activity against a broad-spectrum of pathogens including bacteria, virus, fungi or the like upon contact. The fabric layer <NUM> thus serves as a first-tier barrier against any air-borne contaminants by its self-disinfecting, anti-viral and anti-microbial effects due to the presence of the metallic silver-coated yarn, with the disinfecting effect further supported by the natural filtering action of the woven fabric of the fabric layer <NUM>.

The at least one polymer layer <NUM> comprises thermoplastic polyurethane (TPU) polymer. In one specific embodiment, the TPU polymer layer <NUM> is of a thickness ranged from about <NUM> to about <NUM>, and more preferably, about <NUM>. The TPU polymer layer <NUM> is preferably porous to allow an effective transmission of moisture vapor for an enhanced breathability. In one embodiment, the TPU polymer layer <NUM> is of a moisture vapor transmission rate (MVTR) of more than <NUM>/m<NUM> × <NUM> hrs (measured based on the ASTM E96BW <NUM> standard). More preferably, the TPU polymer layer <NUM> also demonstrates good water resistance and stretchability. For example, in one embodiment the TPU polymer layer <NUM> is of a water-resistance of more than <NUM> mmH<NUM>O (measured based on the JIS L1092B standard), and a stretchability of more than <NUM> MPa (measured based on the ASTM D882 standard).

The TPU polymer layer <NUM> thus serves as a second-tier barrier against the air-borne contaminants by providing an effective filtration layer. For example, with the single composite layer formed from lamination of the first fabric layer <NUM>, the TPU polymer layer <NUM>, and the second fabric layer <NUM>, the resulting face mask <NUM> demonstrates a bacterial filtration efficiency (BFE) of more than <NUM>%. In one embodiment, the bacterial filtration efficiency (BFE) is found to be maintained as more than <NUM>% after <NUM>-<NUM> times of hand washings. In one embodiment, the composite layer formed from lamination of the first fabric layer <NUM>, the TPU polymer layer <NUM>, and the second fabric layer <NUM> is of a preferred thickness ranged from about <NUM> to about <NUM>, more preferably, about <NUM> to about <NUM>.

In one embodiment, it is preferred that the first fabric layer <NUM> and the second fabric layer <NUM> which sandwich the TPU polymer layer <NUM> each comprise the metallic silver fiber or yarn material. In another embodiment, only one of the two fabric layers <NUM>, <NUM>, such as the first, externally facing fabric layer <NUM>, preferably comprises the metallic silver fiber or yarn material. In one further embodiment, one or more additional fabric layers formed from such as, but are not limited to, polypropylene fabric materials, cellulose fiber materials such as cotton and/or bamboo fabric materials, activated carbon comprising fabric materials, etc., can be added between the first and the second fabric layers <NUM>, <NUM> to improve wearing comfort and/or to further increase the filtration efficacy. In one embodiment, these one or more additional fabric layers are preferably arranged between the TPU polymer layer <NUM> and the second fabric layer <NUM>.

The face mask <NUM> may further comprise a nose engaging means <NUM>, which can be provided in the form of an elongated deformable member arranged at a center region of an upper edge of the face covering portion <NUM> for a closer-fitting of the upper edge of the face mask <NUM> across the wearer's nose and face. In one embodiment, the nose engaging mean <NUM> may comprise a deformable wire or the like which forms a nose clip. The nose engaging means <NUM> may further comprise an extended portion <NUM>, such as the two end extensions <NUM> as shown in the figure, to further allow a closer fitting of the face mask <NUM> against the wearer's face. Both the nose engaging means <NUM> and the extended portions <NUM> are preferably finger-manipulatable to allow conformation of the mask with a contour or contours of the wearer's face.

In one embodiment, the at least one fabric layer <NUM> and the at least one polymer layer <NUM> are laminated to form the single composite layer via a hot melt processing technique. In this process, polyurethane (PUR) heat melt adhesive is heated to a required viscosity and is transferred to the surface of the TPU polymer layer <NUM> in the form of melted adhesive dots. The melt adhesive will then be evenly spread out to become a homogenous thin layer and subsequently, binding the TPU polymer layer <NUM> with the one or more fabric layers <NUM>, <NUM> under the action of a heated roller. The process is generally simple, fast and of relatively low cost which does not require complicated machinery and processing steps. Furthermore, the thin layer of adhesive when set does not substantially hinder the breathability of the resultant composite layer. In one further embodiment, the hot melt adhesive may also be spray under high temperature and pressure onto the TPU polymer layer <NUM> to allow atomization of the adhesive for a fine and even coating onto the TPU polymer layer <NUM>.

In one embodiment, the composite layer is formed as a thin, flat sheet of composite layer material and then cut and sewn to form the face covering portion <NUM> of the mask <NUM> in a desired shape generally conforming to a shape of a user's face. The edges surrounding the face covering portion <NUM> may be formed as a seam extending around the face covering portion <NUM> to thereby strengthen the mask <NUM> and provide useful anchor points to which the ear straps <NUM> may be attached. The deformable elongated member <NUM> may be secured in position within an upper seam which, in use, extends across a user's nose and/or face. Preferably, the material forming the seam is also stretchable but with a certain degree of rigidity to strengthen the mask <NUM>.

Forming the composite layer as a single composite flat layer and then cutting and sewing said layer provides a simple, straight forward and efficient way of mass producing a face mask using existing manufacturing facilities and furthermore, allows face masks of various sizes to be readily formed as required.

The stretchability of the composite layer renders the mask <NUM> more comfortable than many conventional masks to wear greatly reducing the user's tendency to adjust and therefore touch the mask <NUM> during use.

By forming the surrounding seam to have a degree of stretchability, although less than that of the composite layer, provides not only strength to the mask but also a closer fit around the edge of the mask, i.e. around the seam, to improve comfort, but, more importantly, to reduce air escaping past the edges of the mask when worn by a user when inhaling or exhaling.

A further benefit of forming a seam around the face covering portion <NUM> is to provide a convenient means for securing the deformable elongated member <NUM> such as a nose clip <NUM> in place and to allow an extension <NUM> of such member <NUM> to be included in the mask <NUM> to better conform the mask to a user's face over their nose and upper cheeks. Preferably, in an adult mask <NUM>, the deformable member <NUM> is at least about <NUM> to about <NUM> in length and/or extends at least across <NUM>% of the length of the top seam of the mask <NUM> and more preferably, equal to or more than <NUM>% of the length of the top seam of the mask <NUM>.

Although the embodiments as described and illustrated in the present specification relate to a composite material for use in a face mask or a face cover, the present invention shall not be limited only to this specific application. Instead, a skilled person in the relevant art should readily understood that the composite material and its manufacturing methods are also applicable to the manufacturing of other types of personal protective equipment such as, but are not limited to, protective clothing, gloves, hats, socks, shoes or the like, as well as other wearable items such as general clothing, gloves, footwears and headwears, etc. to protect the wearers from harmful contaminants.

The present invention is therefore advantageous in that it provides a reusable face mask comprising at least one anti-microbial, metallic silver-comprising fabric layer and at least one highly stretchable, water resisting and breathable filter layer. The two layers are shaped to substantially the same shape and size and are laminated to form a single composite layer via a heat melt lamination process. The resulting composite layer is extremely thin with superior breathability and stretchability, as well as a bacterial filtration efficiency of higher than <NUM>% even after <NUM>-<NUM> washings. The metallic silver-comprising fabric layer provides a self-disinfecting effect, and is found to demonstrate an effective anti-microbial action to successfully reduce viability of harmful pathogens six times faster than a control fabric formed without the metallic silver yarn. The face mask of the present invention requires that the anti-microbial fabric layer and the water resisting and breathable TPU filter layer to be shaped to substantially the same shape and size and thus, for the layers to substantially overlaying each other to ensure that any air stream passing through the laminated, composite layer will have to be effectively filtered by both layers for a more effective protection from the air-borne contaminants.

The present description illustrates the principles of the present invention. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the invention and are included within its scope as defined in the claims.

Moreover, all statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof.

While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only exemplary embodiments have been shown and described and do not limit the scope of the invention in any manner. It can be appreciated that any of the features described herein may be used with any embodiment. The illustrative embodiments are not exclusive of each other or of other embodiments not recited herein. Accordingly, the invention also provides embodiments that comprise combinations of one or more of the illustrative embodiments described above. Modifications and variations of the invention as herein set forth can be made without departing from the scope thereof, and, therefore, only such limitations should be imposed as are indicated by the appended claims.

Claim 1:
A composite material for use in a face mask (<NUM>), comprising:
a fabric layer (<NUM>) comprising a metallic silver-coated fibre material; wherein the metallic silver-coated fibre material is woven with one or more other fibre materials to form the fabric layer and comprises about <NUM>% to about <NUM>% by weight in respect of a total weight of the fabric layer (<NUM>); and
a polymer layer (<NUM>) comprising thermoplastic polyurethane (TPU);
wherein the fabric layer (<NUM>) and the polymer layer (<NUM>) are laminated to form a single composite layer; the single composite layer extends substantially an entire area of a face covering portion (<NUM>) of the face mask (<NUM>);
wherein the fabric layer (<NUM>) and the polymer layer (<NUM>) are of substantially the same shape and size to overlay each other, such that any air stream passing through the single composite layer of the face covering portion (<NUM>) will be effectively filtered by both the fabric layer (<NUM>) and the polymer layer (<NUM>).