Patent Description:
Surgeons and other healthcare providers often wear a combination of a nonwoven-based surgical suit or gown, a hood with a visor, and an air cooling or ventilation system during operating procedures, particularly orthopedic total joint replacement surgeries such as arthroplasties and revisions of the knee, hip, and shoulder, in order to ensure sterile conditions in the operating room, protect the wearer, and create a comfortable environment for the wearer. During the course of such surgeries, aerosolized or droplets of biological fluid can spray onto the visor, obstructing the view of the surgeon or other healthcare provider. Thus, in order to provide surgeons and other healthcare providers with improved visibility, the visor can include one or more removable transparent films, where the surgeon or other healthcare provider can remove or peel away the transparent film should it become covered with biological fluids, tissue, etc., thus exposing a clean, unobstructed surface of an additional removable transparent film or the transparent base film of the visor positioned below the transparent film that was removed. The transparent films must be sterile, and because the transparent films are in close contact with each other, adequate sterilization of the transparent films is often problematic.

Currently, ethylene oxide (EO) gas is used to sterilize all nonwoven-based surgical suits or gowns and hoods. However, a problem exists when using EO gas to sterilize visors with multiple transparent films, as the transparent films are typically in direct contact with each other and such polyester films are not gas-permeable. The direct contact between film layers and non-permeability of the polyester film thereby prevents the EO gas from penetrating through the outermost, exposed transparent film to sterilize the underlying additional transparent films present.

In some cases, radiation sterilization, such as gamma or e-beam irradiation, is used to pre-sterilize visors with multiple transparent films in order to sterilize the underlying transparent films that are not exposed. However, radiation sterilization of the visor must occur prior to affixing the visor to a hood or suit of a personal protection system. If radiation sterilization were used on the final personal protection system, e.g., hood including the visor and one or more nonwoven-based gowns or suits, the polypropylene nonwoven fabric would suffer degradation that may include loss of strength, durability, or integrity, as well as generating unwanted odors, as a result of the radiation. In addition, stability of the nonwoven fabric over time may suffer unacceptably as a result of such radiation. Thus, the pre-sterilization step of radiation is required to sterilize the multi-layer visor prior to affixing the visor to the personal protection system, which is followed by sterilization of the final converted personal protection system using EO gas. However, the performance of separate pre-sterilization of the multi-layer visor in addition to EO gas sterilization of the final surgical hood or personal protection system significantly increases both the time and the cost of manufacturing.

Consequently, a need exists for a visor having a transparent base film and one or more transparent removable films attached thereto that does not require a separate step of pre-sterilization of the visor prior to incorporating the visor into a hood and/or surgical suit or gown with which it will be worn. In particular, a visor having two or more transparent removable films with one or more features to distinguish between each transparent removable film to improve ease of removal would also be useful.

<CIT>) discloses a post-formed successively peelable coextruded polymer film.

<CIT>) discloses a successively peelable coextruded polymer film with embedded antimicrobial layer(s).

<CIT>) discloses a low reflectance optical web.

<CIT>) discloses spatially modified elastic laminates.

<CIT>) discloses the manufacture of a hood for use in a personal protection system.

<CIT>) discloses articles having a polymer grafted cyclodextrin.

According to a first aspect of the invention, there is provided a method of manufacturing a multi-layer visor system for a personal protection system, as is set forth in Claim <NUM> of the accompanying claims.

The present invention is directed to a method of manufacturing a multi-layer visor system for a personal protection system. The multi-layer visor system includes a base film layer and a first removable film layer releasably coupled to an outer-facing surface of the base film layer, wherein the base film layer defines a perimeter and the first removable film layer defines a perimeter, wherein the perimeter of the first removable film layer is contained completely within the perimeter of the base film layer. The method includes the steps of: coextruding a visor film including a base film and a first removable film; cutting the base film and the first removable film in the shape of the perimeter of the base film layer; and cutting the first removable film in the shape of the perimeter of the first removable film layer.

In one particular embodiment, the outer-facing surface of the base film layer is sterile without a separate sterilization step.

The step of coextrusion is conducted at a temperature of at least about <NUM> degrees Fahrenheit (<NUM> degrees Celsius).

In an additional embodiment, the multi-layer visor system further includes a second removable film layer releasably coupled to an outer-facing surface of the first removable film layer, wherein the second removable film layer defines a perimeter, wherein the perimeter of the second removable film layer is contained completely within the perimeter of the base film layer; wherein the step of coextruding the visor composite film includes coextruding a second removable film with the first removable film and the base film; further including a step of cutting the second removable film to form the perimeter of the second removable film layer. Moreover, the perimeter of the second removable film layer can be contained completely within the perimeter of the first removable film layer. Further, the outer-facing surface of the first removable film layer is sterile without a separate sterilization step.

In yet another embodiment, the step of cutting the base film and the first removable film to form a visor shape having a perimeter is performed by die-cutting.

In still another embodiment, the method further includes steps of: aligning a first strip of colored film with an upper edge of the perimeter of the first removable film layer adjacent to the first removable film layer; and cutting the first strip of colored film to form a first colored tab along the upper edge of the perimeter of the first removable film layer, wherein the first colored tab is configured to facilitate removal of the first removable film from the base film by a user. Moreover, the method can further include steps of: aligning a second strip of colored film with an upper edge of the perimeter of the second removable film layer adjacent to the second removable film layer; and cutting the second strip of colored film to form a second colored tab along the upper edge of the perimeter of the second removable film layer, wherein the second colored tab is configured to facilitate removal of the second removable film layer from the first removable film layer by a user.

According to a second aspect of the invention, there is provided a multi-layer visor system for a personal protection system, as is set forth in Claim <NUM> of the accompanying claims.

The present invention is further directed to a multi-layer visor system for a personal protection system. The visor system includes a base film layer and a first removable film layer releasably coupled to an outer-facing surface of the base film layer. The base film layer and the first removable film layer are coextruded.

In one particular embodiment, the base film defines a perimeter and the first removable film layer defines a perimeter, wherein the perimeter of the first removable film is contained completely within the perimeter of the base film.

In another embodiment, an outer-facing surface of the base film layer is sterile.

In a further embodiment, the base film layer includes a polyester or a polycarbonate.

In yet another embodiment, the first removable film layer includes a polyester or a polycarbonate.

In an additional embodiment, the visor system includes an anti-reflective coating applied to an inner-facing surface of the base film layer.

The visor system includes a protective film releasably coupled to an inner-facing surface of the base film layer.

In one more embodiment, the first removable film layer includes a tab, wherein the tab facilitates removal of the first removable film layer from the base film layer.

In another embodiment, the first removable film layer includes a transparent viewing portion and a colored tab portion.

In a further embodiment, the visor system includes a second removable film layer releasably coupled to an outer-facing surface of the first removable film layer; wherein the first removable film layer and the second removable film layer are coextruded. Moreover, the base film layer defines a perimeter and the second removable film layer defines a perimeter, wherein the perimeter of the second removable film layer may be contained completely within the perimeter of the base film layer. Further, an outer-facing surface of the first removable film layer may be sterile. Moreover, the second removable film layer may include a polyester or a polycarbonate. Further, the second removable film layer can include a tab, wherein the tab facilitates removal of the second removable film layer from the first removable film layer. In addition, the first removable film layer can include a tab; further wherein the tab of the first removable film layer can be visually distinct from the tab of the second removable film layer.

The present invention is further directed to a multi-layer visor system as described above, wherein the surgical hood and the multi-layer visor system are sterile.

According to a further aspect of the invention, there is provided a surgical hood comprising the multi-layer visor system as described above, wherein the surgical hood and the multi-layer visor system are sterile, as is set forth in Claim <NUM> of the accompanying claims.

According to a further aspect of the invention, there is provided a surgical gown including an integrated surgical hood and the multi-layer visor system as described above, wherein the surgical gown, the integrated surgical hood, and the multi-layer visor system are sterile, as is set forth in Claim <NUM> of the accompanying claims.

According to a further aspect of the invention, there is provided a personal protection system including a surgical gown and a separate surgical hood including the multi-layer visor system as described above, wherein the personal protection system is ethylene gas sterilized in a single package, as is set forth in Claim <NUM> of the accompanying claims.

According to a further aspect of the invention, there is provided a method of manufacturing a sterile protective surgical garment, as is set forth in Claim <NUM> of the accompanying claims. The method includes the steps of: providing a multi-layer visor system as described above, wherein an outer-facing surface of the base film layer is sterile; providing a surgical hood comprising a nonwoven fabric material, a helmet, or other headwear; attaching the multi-layer visor system to an attachment area of the surgical hood, helmet, or headwear to form a protective surgical garment; and exposing the protective surgical hood to ethylene oxide gas to sterilize the protective surgical garment.

These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description and appended claims.

As used herein, the terms "about," "approximately," or "generally," when used to modify a value, indicates that the value can be raised or lowered by <NUM>% and remain within the disclosed embodiment. Further, when a plurality of ranges are provided, any combination of a minimum value and a maximum value described in the plurality of ranges are contemplated by the present invention. For example, if ranges of "from about <NUM>% to about <NUM>%" and "from about <NUM>% to about <NUM>%" are described, a range of "from about <NUM>% to about <NUM>%" or a range of "from about <NUM>% to about <NUM>%" are also contemplated by the present invention.

Generally speaking, the present invention is directed to a visor system for a surgical hood that can be a component of a personal protection system, which can include a ventilation system in some embodiments. The present invention is further directed to a method of manufacturing the visor system, and a method of manufacturing a protective surgical garment incorporating the visor system and which does not require a step of pre-sterilization of the visor system. The visor system includes a base film layer and at least a first removable film layer releasably coupled to an outer-facing surface of the base film layer. The base film layer and the first removable film layer are coextruded. Specifically, in one embodiment, a first removable film is releasably coupled to an outer-facing surface of the base film and a second removable film is releasably coupled to an outer-facing surface of the first removable film, and each of the base film layer, first removable film layer, and second removable film layer are coextruded films. The films are coextruded together at sufficiently high temperatures to ensure sterility of each of the film layers. Sterility is conceptualized as the probability that a pathogenic organism will be present on a product. The safe sterility assurance level ("SAL") required by the Food and Drug Administration for medical devices, or "terminal kill," is <NUM>-<NUM>, meaning a probability of one out of one million devices may contain a single organism. Put another way, terminal kill is generally associated with a <NUM>-log reduction in bacteria. Because the temperatures of coextrusion of the films are sufficiently high to achieve "terminal kill", no separate sterilization step is required in order to sterilize each of the layers of the multi-layer visor system. Although it is to be understood that the transparent films of the visor system of the present invention can be formed from polycarbonate or polyester, which are materials through which ethylene oxide gas cannot penetrate, the high temperatures of the coextrusion of the thermoplastic film material is sufficiently high to achieve sterility between the film layers, and the lack of oxygen between each of the film layers enables the sterility to be maintained. Thus, the visor system does not need to be pre-sterilized prior to incorporating the visor system into a sterile protective garment.

In other words, utilizing the coextrusion approach contemplated by the visor system of the present invention allows the formation of a multi-layer visor system that is sterile between each of the layers upon formation of the visor film, which is in stark contrast to current film attachment methods that utilize adhesives. Because ethylene oxide gas cannot penetrate films bonded together via adhesives and cannot penetrate polyester and polycarbonate transparent films, unlike the visor system of the present invention, currently available visor systems often require the use of radiation sterilization (e.g., gamma radiation) as an interim step to sterilize the visor system separately before the visor system can be incorporated into a surgical hood, which is then sterilized by, for instance, EO gas, resulting in a very inefficient and time-consuming sterilization process.

On the other hand, the coextruded film layers contemplated by the present invention allow the high temperature of the coextrusion process to kill biological indicator (BI) microbes to yield an underlying sterile surface of each film layer. The resulting multi-layer visor system of the present invention can thus be formed and then bonded or otherwise attached to a surgical hood or a surgical gown with attached hood, and the entire protective surgical garment can then be sterilized in one step via exposure to ethylene oxide gas, rather than having to sterilize the individual components in multiple steps as required for currently available multi-layer visor systems. This is because the intermediate surfaces of the layers of film of the visor system are sterile upon coextrusion of the film due to the high temperatures of coextrusion, and the inner and outer surfaces of the visor system are then sterilized by ethylene oxide gas along with the rest of the protective surgical garment. This results in a surgical hood and/or gown where all of the transparent films (e.g., the base film and one or more removable films) are sterile in the event that one or more of the outermost transparent films are peeled away from the visor system and discarded as they become soiled.

In addition, it is to be understood that the visor system of the present invention contemplates placement of one or more peel-away tabs for removal of each of the removable film layers around the perimeter of the removable transparent films of the visor system so as to be unobtrusive to the surgeon or other healthcare provider. Moreover, the various transparent films are attached to each other with a bond strength sufficient to secure the transparent films to each other when in use, while also allowing for the surgeon or other healthcare provider to easily peel away and remove an outermost soiled transparent film without dislodging the other layers and the underlying helmet to which the surgical hood and visor system is secured.

The specific features of the visor system and methods of manufacturing of the present invention are discussed in more detail and may be better understood with reference to <FIG>.

Referring now to <FIG>, a front view of one visor system <NUM> contemplated by the present invention is shown. The visor system <NUM> includes a base film <NUM> having a perimeter <NUM> including an upper side <NUM>, a lower side <NUM>, a first lateral side <NUM>, a second lateral side <NUM>, and an outer-facing surface <NUM> (see <FIG>) that is the surface facing away from the wearer's face and may be exposed to the environment when incorporated into a surgical hood and an inner-facing surface (not shown) that is the surface closest to a wearer's face when incorporated into a surgical hood. The base film <NUM> can include tabs <NUM> and <NUM> extending from a first lateral side <NUM> and a second lateral side <NUM> of the visor system <NUM>. Tabs <NUM> and <NUM> can be used to secure the visor system <NUM> to a surgical hood, such as the surgical hood <NUM> shown in <FIG>. The visor system <NUM> also includes at least one removable film, e.g., a plurality of removable films, configured to be easily peeled away to expose a clean film layer underneath. For instance, the visor system <NUM> can include at least a first removable film layer <NUM> having a perimeter <NUM> that can be contained completely within the perimeter <NUM> of the base film layer <NUM>, as shown in <FIG>. For instance, as shown in <FIG>, the visor system <NUM> includes a first removable film layer <NUM>, and a second removable film layer <NUM>, where the second removable film layer <NUM> has a perimeter <NUM> that can be contained completely within the perimeter <NUM> of the base film layer <NUM>. The plurality of removable film layers, e.g. removable film layers <NUM> and <NUM>, can each include tabs (e.g., tabs <NUM> and <NUM>, respectively) that enable the wearer to peel-away the outermost removable film layer <NUM> or <NUM> when it becomes soiled or when the wearer's visibility is otherwise diminished due to the presence of blood, tissue, or other matter coming into contact with the film layer <NUM> or <NUM>.

As shown in <FIG>, in some embodiments, the tabs <NUM> and <NUM> can be present on opposite sides of the visor system <NUM>, e.g., the tab <NUM> of the first removable film layer <NUM> can be adjacent to the first lateral edge <NUM> of the base film layer <NUM> and the tab <NUM> of the second removable film layer <NUM> can be adjacent to the second lateral edge <NUM> of the base film layer <NUM>. Meanwhile, in other embodiments (not shown), both tabs <NUM> and <NUM> can both be present on the same side of the visor system <NUM>. The tabs <NUM> and <NUM> can be present on an upper side of each of the removable film layers <NUM> and <NUM>, respectively, or on one or both of the lateral sides of the removable film layers <NUM> and <NUM>, such that neither of the tabs <NUM> or <NUM> occludes a wearer's field of view through the visor system <NUM>. <FIG> illustrates another alternative arrangement of a visor system 100A having a first removable film layer 140A having a tab 150A on one lateral side of the first removable film layer 140A, and a second removable film layer 160A having a tab 170A on an opposite lateral side of the second removable film layer 160A. Optionally, as shown in <FIG>, the second removable film layer 160A can include a cut-away section <NUM> A on the lateral side opposite the tab 170A and aligned with the tab 150A of the first removable film layer 140A in order to expose the tab 150A and first removable film layer 140A to be able to easily distinguish between the removable layers.

As shown in <FIG>, the base film <NUM> can have a height H1 in the y-direction ranging from about <NUM> inches (in) (<NUM> centimeters or cm) to about <NUM> in (<NUM>), such as from about <NUM> in (<NUM>) to about <NUM> in (<NUM>), for example from about <NUM> in (<NUM>) to about <NUM> in (<NUM>).

Meanwhile, the first removable film layer <NUM> can have a height H2 in the y-direction, including the tab <NUM>, ranging from about <NUM> in (<NUM>) to about <NUM> in (<NUM>), such as from about <NUM> in (<NUM>) to about <NUM> in (<NUM>), for example from about <NUM> in (<NUM>) to about <NUM> in (<NUM>). When measured without including the tab <NUM>, the first removable film layer <NUM> can have a height H3 in the y-direction extending from the upper edge <NUM> to the lower edge <NUM> ranging from about <NUM> in (<NUM>) to about <NUM> in (<NUM>), such as from about <NUM> in (<NUM>) to about <NUM> in (<NUM>), for example from about <NUM> in (<NUM>) to about <NUM> in (<NUM>).

The second removable film layer <NUM> can also have a height H3 in the y-direction including the tab <NUM> ranging from about <NUM> in (<NUM>) to about <NUM> in (<NUM>), such as from about <NUM> in (<NUM>) to about <NUM> in (<NUM>), for example from about <NUM> in (<NUM>) to about <NUM> in (<NUM>), i.e., the height of the second removable film layer <NUM> including tab <NUM> can be approximately equal to the height of the first removable film layer <NUM> excluding the tab <NUM>. When measured without including the tab <NUM>, the second removable film layer <NUM> can have a height H4 in the y-direction ranging from about <NUM> in (<NUM>) to about <NUM> in (<NUM>), such as from about <NUM> in (<NUM>) to about <NUM> in (<NUM>), for example from about <NUM> in (<NUM>) to about <NUM> in (<NUM>).

In addition, the base film layer <NUM> can have an overall width W1 in the x-direction including the tabs <NUM> and <NUM> ranging from about <NUM> in (<NUM>) to about <NUM> in (<NUM>), such as from <NUM> in (<NUM>) to about <NUM> in (<NUM>), for example from about <NUM> in (<NUM>) to about <NUM> in (<NUM>), and a width W2 in the x-direction excluding the tabs <NUM> and <NUM> ranging from about <NUM> in (<NUM>) to about <NUM> in (<NUM>), such as from about <NUM> in (<NUM>) to about <NUM> in (<NUM>), such as from about <NUM> in (<NUM>) to about <NUM> in (<NUM>).

Moreover, the first removable film layer <NUM> and the second removable film layer <NUM> can each have a width W3 in the x-direction ranging from about <NUM> in (<NUM>) to about <NUM> in (<NUM>), such as from about <NUM> in (<NUM>) to about <NUM> in (<NUM>), for example from about <NUM> in (<NUM>) to about <NUM> in (<NUM>).

Additionally, the tabs <NUM> and <NUM> can have a width W4 ranging from about <NUM> in (<NUM>) to about <NUM> in (<NUM>), such as from about <NUM> in (<NUM>) to about <NUM> in (<NUM>), for example from about <NUM> in (<NUM>) to about <NUM> in (<NUM>).

Further, regardless of the dimensions of each of the film layers <NUM>, <NUM>, and <NUM>, or the number of removable films present in the visor system <NUM>, the films can each be transparent and can each be formed from polycarbonate or polyester. In one particular embodiment, the films <NUM>, <NUM>, and <NUM> can be polyester. For instance, the films can be formed from clear polymer polyethylene terephthalate, commonly referred to as PET. PET is thermoplastic, i.e., it softens and melts at high temperatures.

The films according to the invention can be manufactured in various ways. A preferred manufacturing method uses coextrusion, for example through flat film coextrusion. Furthermore, both individual and all coatings of the film according to the invention can be formed by extrusion, particularly through flat film coextrusion. Referring now to <FIG>, in flat film coextrusion of the visor film <NUM>, molten polymer, e.g., polyester, is cast through multiple extruders and die slots, e.g., flat dies, that meet at an exit opening, to adopt its flat film shape. The coextrusion process can deliver polymer, e.g., polyester, at a range of melt temperatures and viscosities/densities that cool differentially. The coextruded films <NUM>, <NUM> and <NUM> can be connected by ultra-thin tie layers that provide adhesion to the surface adjacent to it (i.e., between the base film <NUM> and the first removable film <NUM>, and between the first removable film <NUM> and the second removable film <NUM>, respectively) while maintaining ease of release between the films <NUM>, <NUM>, <NUM> in the final multi-layered visor film <NUM>.

The visor film <NUM> may optionally include one or more protective films <NUM>, as shown in <FIG>, which may form the outermost layers of the visor film <NUM>. The protective film(s) <NUM> may be formed of any suitable protective thermoplastic film material, e.g., polyethylene film. The protective film(s) <NUM>, when present, can maintain the sterility of the base film <NUM> and/or the second removable film <NUM> and protect the integrity of the base film <NUM> and/or the second removable film <NUM>, e.g., to protect from scratches. In alternative aspects of the invention, the protective film(s) <NUM> can be applied on either of the outermost layers of the visor film <NUM> or visor system <NUM> after the coextrusion of the base film <NUM>, first removable film <NUM> and second removable film <NUM> of the visor film <NUM>. For instance, in an embodiment of the visor system <NUM> (not shown), a protective film <NUM> may be applied over the second removable film layer <NUM> after the adhesive gasket <NUM> has been applied to the base film layer <NUM>, which will be described in greater detail below.

In some aspects of the invention, the melting temperature of the polyester material from which the films <NUM>, <NUM>, and <NUM> are coextruded can in in a range from about <NUM> to about <NUM> degrees Fahrenheit (about <NUM> to about <NUM> degrees Celsius). Thus, when coextruded, the layers of molten polyester forming each of the films <NUM>, <NUM> and <NUM> is generally at a temperature equal to or greater than the melting temperature of about <NUM>-<NUM> degrees Fahrenheit. The very high melting temperature of the polyester material that is coextruded to form the films <NUM>, <NUM>, <NUM> that form each of the layers <NUM>, <NUM> and <NUM> of the visor system <NUM> contributes to the sterility of the visor system <NUM> by ensuring sterility between each of the layers <NUM>, <NUM> and <NUM>.

For comparison, hospital steam autoclave systems achieve terminal kill at recommended temperatures of about <NUM>-<NUM> degrees Fahrenheit for sterilizing surgical instruments. Sterility is conceptualized as the probability that a pathogenic organism will be present on a product. The safe sterility assurance level ("SAL") required by the Food and Drug Administration for medical devices, or "terminal kill," is <NUM>-<NUM>, meaning a probability of one out of one million devices may contain a single organism. Put another way, terminal kill is generally associated with a <NUM>-log reduction in bacteria.

Thus, by far exceeding the recommended temperature range for terminal kill by coextruding polyester at a melt temperature of from about <NUM> to about <NUM> degrees Fahrenheit, and by coextruding the films such that there is no space, e.g., air or oxygen, in between the films, the present inventors have found that coextrusion of the polyester films can achieve a sterile outer surface of the base film <NUM>, which forms the base film layer <NUM> of the visor system <NUM>, and a sterile outer surface of the first removable film layer <NUM>, which forms the first removable film layer <NUM> of the visor system <NUM>, without requiring a separate or distinct step of sterilizing the layers of the visor system <NUM>. In a laboratory test for sterility of the coextruded film <NUM>, <NUM> sample visors <NUM> formed from the coextruded film <NUM> were tested for sterility and microbe growth. All <NUM> visors were confirmed through testing to have no microbe growth and thus confirmed as sterile. Notably, current standards for sterility state that a sample size of <NUM>, as was tested with the <NUM> visors, is acceptable to establish sterility of a product. Therefore, the visor <NUM> of the present invention meets sterility standards.

For instance, as shown in <FIG>, a visor film <NUM> may be coextruded including a base film <NUM>, a first removable film <NUM> and a second removable film <NUM>, which each form the base film layer <NUM>, first removable film layer <NUM> and second removable film layer <NUM>, respectively, when the visor system <NUM> is formed. As shown in <FIG>, the visor film <NUM> may additionally include a release layer <NUM> between the base film <NUM> and the first removable film <NUM>, and between the first removable film <NUM> and the second removable film <NUM>. The release layer <NUM> may be a distinct film, as shown in <FIG>, or it may be one or more additive composition(s) mixed and coextruded with the base film <NUM>, first removable film <NUM> or second removable film <NUM>. The release layer <NUM> is configured to enable each of the removable films <NUM>, <NUM> to separate easily from the respective adjacent layers of film when the visor system <NUM> is formed. Each of the release layers <NUM> are configured to be removed along with an outer removable film layer. For instance, when the second removable film layer <NUM> of the visor system <NUM> is peeled away, both the second film <NUM>, which forms the second removable film layer <NUM> of the visor system <NUM>, and the release layer <NUM> immediately adjacent to the second film <NUM> as shown in <FIG>, are peeled away together.

Further, as shown in <FIG>, the base film layer <NUM> formed from the base film <NUM> of the visor film <NUM> can have a film thickness T1 in the z-direction ranging from about <NUM> micrometers (<NUM> mils) to about <NUM> micrometers (<NUM> mils) (<NUM> mil is <NUM> inches), such as from about <NUM> micrometers (<NUM> mils) to about <NUM> micrometers (<NUM> mils), such as from about <NUM> micrometers (<NUM> mils) to about <NUM> micrometers (<NUM> mils). In one particular embodiment, the base film layer thickness T1 may be about <NUM> micrometers (about <NUM> mils). The removable film layers <NUM> and <NUM> formed from the removable films <NUM> and <NUM> of the visor film <NUM> can each have a thickness T2 in the z-direction ranging from about <NUM> micrometers (<NUM> mils) to about <NUM> micrometers (<NUM> mils), such as from about <NUM> micrometers (<NUM> mil) to about <NUM> micrometers (<NUM> mils), such as from about <NUM> micrometers (<NUM> mils) to about <NUM> micrometers (<NUM> mils). In one particular embodiment, the removable film layers <NUM> and <NUM> can each have a thickness T2 of about <NUM> micrometers (about <NUM> mils). The release layers <NUM> of the visor film <NUM> can account for a thickness T3 in the z-direction of the film <NUM> in a range from about <NUM> micrometers (<NUM> mils) to about <NUM> micrometers (<NUM> mil). Additionally, when present, the protective film(s) <NUM> can have a thickness T4 in the z-direction in a range from about <NUM> micrometers (<NUM> mils) to about <NUM> micrometers (about <NUM> mils). A total thickness T5 of the multi-layer visor system <NUM> in the z-direction, as measured, e.g., using calipers, can be in a range from about <NUM> micrometers (about <NUM> mils) to about <NUM> micrometers (about <NUM> mils).

When viewing through the visor system <NUM> having base film layer <NUM> and a plurality of removable film layers, e.g., <NUM> and <NUM>, the visor system <NUM> appears to be one single piece of plastic film. The present inventors have found that the transparency, i.e., the percentage of transmission of light, of the visor system <NUM> is inversely related to the number of layers of film(s) used to form the visor system <NUM>. Thus, a visor system <NUM> having fewer layers generally may have a higher percentage of light transmission than a visor system having a greater number of layers. In order to provide a sufficient field of view for a surgeon or other user of the visor system <NUM> of the present invention, the visor system <NUM> has a target light transmission percentage of about <NUM>% or greater, such as about <NUM>% or greater, for instance about <NUM>% or greater. In addition, a high value of clarity is necessary in order to provide a sufficient field of view for a surgeon or other user of the visor system <NUM> of the present invention. The visor system <NUM> has a target clarity percentage of about <NUM>% or greater, such as about <NUM>% or greater, for instance about <NUM>% or greater. The present inventors have found that the desire of the surgeons or other users of the visor system <NUM> for removable peel-away layers is balanced with the criticality of the transparency and clarity of the visor system <NUM> for the surgeons and/or other users, e.g., to be able to have a clear field of view to perform a surgery or other medical procedure. The visor system of the present invention may generally include a number of peel-away film layers, such as from one (<NUM>) to about four (<NUM>) peel-away layers while maintaining at least about <NUM>% light transmission and at least about <NUM>% clarity.

Typical polyester film reflects back incident light by about <NUM> - <NUM> % and is sufficient to cause eye strain/fatigue. Thus, an anti-reflective coating <NUM> may be applied, e.g., aqueously applied, or coextruded on the inner-facing surface of the base film <NUM> as shown in <FIG>. The anti-reflective coating <NUM> is configured to reduce glare of the visor system <NUM>. Glare is caused by a significant ratio of luminance between the task (that which is being looked at) and the glare source, e.g., light source. In some aspects, the anti-reflective coating <NUM> may be an anti-reflective and anti-fog coating for reducing both glare and fogging of the visor system <NUM>. For example, one particular anti-reflective, anti-fog coating that may be applied to the base film <NUM> is the AFAR anti-fog anti-reflective offered by <NUM>™. The AFAR technology has greater than <NUM>% light absorption, thereby significantly reducing glare.

After the formation of the visor film <NUM>, e.g., by coextrusion as described above, the visor system <NUM> may be formed by cutting each of the individual layers <NUM>, <NUM> and <NUM> from the visor film <NUM>. One such method is die-cutting or kiss-cutting of the visor film <NUM> to form the visor layers <NUM>, <NUM>, <NUM>. For instance, a first die-cut in the shape of the perimeter <NUM> of the base film layer <NUM> of the visor system <NUM> may cut through all of the layers of the visor film <NUM>. Then, a second die-cut in the shape of the perimeter <NUM> of the first removable film layer <NUM> may cut through the second removable film <NUM> and the first removable film <NUM>, along with the release layers <NUM>, to form the first removable film layer <NUM>. Next, a third die-cut in the shape of the perimeter <NUM> of the second removable film layer <NUM> may cut through just the second removable film <NUM> and its adjacent release layer <NUM> to form the second removable film layer <NUM>. Thus, each of the film layers <NUM>, <NUM> and <NUM> of the visor system <NUM> may be die-cut from the visor film <NUM>, each having distinct shapes and dimensions, as described above and illustrated in <FIG>. In other aspects of the invention, the visor system <NUM> may be formed from the visor film <NUM>, e.g., by laser cutting each of the layers <NUM>, <NUM>, and <NUM> in the desired shape, or any other suitable method that is capable of cutting each of the layers <NUM>, <NUM>, and <NUM> to shape from the visor film <NUM>.

Turning next to <FIG>, the tabs <NUM> and <NUM> of the first removable film layer <NUM> and second removable film layer <NUM>, respectively, may be formed having different shapes, colors, textures, and/or other distinctive features in order to enable a wearer to easily distinguish between the tabs <NUM> and <NUM>. Thus, it can be easier for a wearer to know which tab to pull first to remove the outermost, i.e., second removable film layer <NUM>, using the tab <NUM>. For instance, as is shown in <FIG>, <FIG>, the tab <NUM>, shown in detail in <FIG>, has a different shape than the tab <NUM>, shown in detail in <FIG>. For instance, the tab <NUM> may be a three-sided shape having an upper side <NUM> a, a lower side <NUM> b adjacent to the first removable film layer <NUM> as shown in <FIG>, and a lateral side <NUM> c. The upper side 151a may be sloped between an upper end of the lateral side 151c to an opposite end of the lower side 151b as shown in <FIG>. In contrast, the tab <NUM> may be a foursided tab having an upper side 171a, a lower side 171b adjacent to the second removable film layer <NUM>, a first lateral side 171c and a second lateral side 171d. The first and second lateral sides 171c and 171d may each connect between the upper side 171a and the lower side 171b such that the tab <NUM> forms a generally quadrilateral shape, e.g., a rectangular shape or a trapezoidal shape. Thus, the different shapes of the tabs <NUM> and <NUM> can help a user distinguish between the two tabs in order to determine which tab should be pulled first.

In addition, the second tab <NUM> may be formed having a first color, and the first tab <NUM> may be formed having a second color, where the second color is different from the first color. Ideally, the second color is visually contrasting to the first color in order to easily distinguish between the two colors. The colors of each of the tabs <NUM> and <NUM> may be formed from colored tapes of two distinct colors, e.g., coextruded with the visor film <NUM> or attached to the removable film layers <NUM> and <NUM> after cutting the visor system <NUM> from the visor film <NUM>.

The tabs <NUM> and/or <NUM> can additionally be formed having different textures so that a wearer can distinguish between the tabs based on tactile feel. For instance, the tab <NUM> can include textured elements <NUM> as shown in <FIG>, while the tab <NUM> may be smooth without any textured elements. The textured elements <NUM> can be formed on the tab by any suitable means, e.g., coextrusion during formation of the visor film <NUM>, printing, imprinting, or otherwise additive manufacturing, molding, or any other suitable means of achieving a textured surface. Generally, the outer-facing surface of the tab is provided with textured elements <NUM> so that a wearer may feel the textured elements <NUM>, although in some aspects, both surfaced of the tab may be provided with textured elements <NUM>. The textured elements <NUM> may be disposed in a pattern, e.g., lines such as straight or curved lines, dashes, dots and/or a dash-dot pattern, circles, swirls, checkered pattern, diagonal pattern, or any other pattern, or the textured elements <NUM> may be applied randomly with no uniform pattern formed.

As illustrated in <FIG>, one or more of the tabs, e.g., tab <NUM>, may additionally include a crease <NUM> along which the tab <NUM> may be folded or creased in order to form a three-dimensional shape, as shown in <FIG>, which is a cross-sectional view of the tab <NUM> of <FIG> taken along the line E-E. The tab may include one or more creases <NUM>. For instance, a plurality of creases <NUM> may be used to form a crinkled or uneven texture. The crease <NUM> as shown in <FIG> can enable a wearer to more easily locate and grasp the tab <NUM>, e.g., by folding the upper side 171a of the tab <NUM> in a direction away from the visor system <NUM>. The crease <NUM> can form an angle in a range from about <NUM> degrees to about <NUM> degrees, such as from about <NUM> degrees to about <NUM> degrees, for instance about <NUM> degrees to about <NUM> degrees.

Turning back to <FIG>, an adhesive gasket <NUM> may be applied to the base film layer <NUM>. The adhesive gasket <NUM> is configured to adhere the visor system <NUM> to a surgical hood, e.g., as shown in <FIG>. The adhesive gasket <NUM> is defined by an inner perimeter <NUM> and an outer perimeter <NUM>, whereby the inner perimeter <NUM> surrounds the perimeter <NUM> of the first removable film layer <NUM> such that the removable film layers <NUM>, <NUM> remain fully exposed when the visor system <NUM> is attached to the surgical hood <NUM>. The adhesive gasket <NUM> can be formed from any suitable adhesive material. For instance, a hot-melt adhesive, e.g., a low temperature polyolefin hot melt adhesive or glue, may be used. Alternative adhesives may include pressure-sensitive adhesive or heat-activated adhesive. After applying the adhesive gasket <NUM> to the base film layer <NUM> but prior to attaching the visor system <NUM> to the surgical hood <NUM>, a protective film <NUM> may be placed over the visor system <NUM> in contact with the adhesive gasket <NUM> in order to protect the outer layer, e.g., second removable film layer <NUM>, of the visor system and the adhesive gasket <NUM> until the surgical hood <NUM> is ready for assembly.

During assembly, or conversion, of the visor system <NUM> into a surgical hood <NUM> as shown in <FIG>, the protective film <NUM> adjacent to the second removable film layer <NUM> can be removed to expose the adhesive gasket <NUM>. Then, the visor system <NUM> can be inserted into an interior portion of a surgical hood <NUM> or other medical helmet or garment. For instance, the surgical hood <NUM> can be made of a nonwoven barrier fabric, e.g., a polypropylene nonwoven fabric <NUM>. The surgical hood <NUM> can include a cut-out area <NUM> configured to receive the visor system <NUM> which is surrounded by an attachment region <NUM>. The adhesive gasket <NUM> is then adhered to the attachment region <NUM> on the inner portion of the surgical hood <NUM>, as shown in <FIG>. After assembling the surgical hood <NUM>, a protective film <NUM> on the inner side of the base film layer <NUM>, if present, is removed. Then, the surgical hood <NUM> is ready for final packaging and sterilization. The entire protective surgical garment, e.g., surgical hood <NUM> including the visor system <NUM>, can then be sterilized in one step via exposure to ethylene oxide gas. The EO gas penetrates and sterilizes the nonwoven fabric of the surgical hood <NUM> as well as the exposed surfaces of the visor system <NUM>, while the inner layers of the visor system <NUM> remain sterilized due to the high temperatures of coextrusion of the visor film <NUM> from which the visor system <NUM> is formed. This results in a surgical hood and/or gown where all of the transparent films (e.g., the base film and one or more removable films) are sterile in the event that one or more of the outermost transparent films are peeled away from the visor system and discarded as they become soiled. Due to the sterility of the inner layers of the visor system <NUM> resulting from the high temperatures of coextrusion of the visor film <NUM>, as described above, there is no need for pre-sterilization of the visor system <NUM> prior to assembling the surgical hood <NUM>.

As shown in <FIG>, the present invention is further directed to a method of manufacturing a multi-layer visor system and a protective surgical garment incorporating the multi-layer visor system. In step <NUM>, a visor composite film including a base film and a first removable film is coextruded. Optionally, a second removable film is also coextruded in the formation of the visor composite film. The base film, first removable film, and second removable film are formed from thermoplastic polyester or polycarbonate material having a melting temperature in a range from about <NUM> degrees Fahrenheit to about <NUM> degrees Fahrenheit (about <NUM> to about <NUM> degrees Celsius). The coextrusion step <NUM> is carried out at a temperature greater than the melting temperature, i.e., at least about <NUM> degrees Fahrenheit. Then, beginning in step <NUM>, the visor system <NUM> is cut out from the visor composite film. Specifically, in step <NUM>, each layer of the visor composite film is cut in the shape of the perimeter of the base film layer. Then, in step <NUM>, the first removable film and the second removable film, if present, are cut in the shape of the perimeter of the first removable film layer. Optionally, the perimeter <NUM> of the first removable film layer <NUM> includes the shape of the first tab <NUM>. Next, in step <NUM>, the second removable film is cut in the shape of the perimeter of the second removable film layer, resulting in a visor system <NUM> having two removable film layers such that the perimeters <NUM> and <NUM> of both the first removable film layer <NUM> and the second removable film layer <NUM>, respectively, are contained within the perimeter <NUM> of the base film layer <NUM>. Optionally, the perimeter <NUM> of the second removable film layer <NUM> includes the shape of the first tab <NUM>. Further, the shape of the first tab <NUM> and the shape of the second tab <NUM> may be different or distinct from each other to enable a user to easily distinguish between the first tab <NUM> and the second tab <NUM>. Moreover, due to the high temperature at which the coextrusion step <NUM> is carried out, an outer surface of the base film layer <NUM> adjacent to the first removable film layer <NUM> and an outer surface of the first removable film layer <NUM> adjacent to the second removable film layer <NUM> are sterile as manufactured, without any need for an additional or separate step of sterilizing the layers of the visor system <NUM>. In some aspects of the method, the cutting performed in steps <NUM>, <NUM> and <NUM> can be done by die-cutting, e.g., kiss-cutting, or by laser cutting, or any other suitable means for cutting through some but not all layers of a film.

Then, in step <NUM>, a first strip of colored film may be aligned with an upper edge <NUM> of the perimeter <NUM> of the first removable film layer adjacent to the first removable film layer <NUM>. In step <NUM>, the first strip of colored film is cut to form a first colored tab <NUM> along the upper edge <NUM> of the perimeter <NUM> of the first removable film layer <NUM>. The first colored tab is configured to facilitate removal of the first removable film from the base film by a user. Next, in step <NUM>, a second strip of colored film may be aligned with an upper edge <NUM> of the perimeter <NUM> of the second removable film layer <NUM> adjacent to the first removable film layer. In step <NUM>, the second strip of colored film is cut to form a second colored tab <NUM> along the upper edge <NUM> of the perimeter <NUM> of the second removable film layer <NUM>. The second colored tab <NUM> is configured to facilitate removal of the second removable film <NUM> from the visor system <NUM> by a user.

In step <NUM>, an adhesive gasket <NUM> is applied to an outer surface of the base film layer <NUM> having an adhesive gasket inner perimeter <NUM>, which surrounds the perimeter <NUM> of the first removable film layer <NUM>, and an adhesive gasket outer perimeter <NUM>, which is contained within the perimeter <NUM> of the base film layer <NUM>. In step <NUM>, one or more protective films <NUM> are applied to the outer surfaces of the visor system <NUM> to protect the layers of the visor system <NUM> and the adhesive gasket <NUM>.

As shown in <FIG>, the invention is further directed to a method of manufacturing a sterile protective surgical hood that includes the visor system <NUM>. In step <NUM>, the visor system <NUM> as described above and shown in <FIG> is provided. For instance, the visor system <NUM> may be manufactured according to the method <NUM> shown in <FIG>. An outer-facing surface of the base film layer <NUM> of the visor system <NUM> is sterile due to the high temperature at which the base film layer <NUM> was extruded along with the first removable film layer <NUM> and the second removable film layer <NUM>. Thus, no step of pre-sterilization of the visor system <NUM> is needed. Next, a surgical hood comprising a nonwoven fabric material, or a helmet or other protective headwear, is provided in step <NUM>. If not already present, a visor aperture is cut out of the surgical hood, helmet, or headwear. In step <NUM>, the multi-layer visor system <NUM> is attached to an attachment area <NUM> of the surgical hood, helmet or headwear to form a protective surgical garment. The adhesive gasket <NUM> of the multi-layer visor system <NUM> is used to attach to the attachment area <NUM>. Then, in step <NUM>, the entire protective surgical garment is sterilized in a single package, e.g., by exposure to ethylene oxide gas. In other words, by using the visor system <NUM> made from a coextruded visor film <NUM> as described above, which results in sterile inner surfaces of each visor layer, the entire protective surgical garment may be sterilized in one single sterilization step without any need for pre-sterilization of the visor system <NUM>.

Claim 1:
A method of manufacturing a multi-layer visor system (<NUM>) for a personal protection system, the multi-layer visor system (<NUM>) comprising a base film layer(<NUM>) , a first removable film layer (<NUM>) of one or more removable film layers releasably coupled to an outer-facing surface of the base film layer (<NUM>), a first release layer (<NUM>) disposed between the base film layer (<NUM>) and the first removable film layer (<NUM>), wherein the first release layer (<NUM>) is configured to enable separation of the first removable film layer (<NUM>) from the outer-facing surface of the base film layer (<NUM>), a first protective film (<NUM>) releasably coupled to an inner-facing surface of the base film layer (<NUM>) and a second protective film (<NUM>) releasably formed over an outermost removable film layer of the one or more removable film layers, wherein the base film layer (<NUM>) defines a perimeter (<NUM>) and the first removable film layer (<NUM>) defines a perimeter (<NUM>), wherein the perimeter (<NUM>) of the first removable film layer (<NUM>) is contained completely within the perimeter (<NUM>) of the base film layer (<NUM>), the method comprising the steps of:
coextruding a visor film (<NUM>) including the base film layer (<NUM>), the first release layer (<NUM>) and the first removable film layer (<NUM>) of one or more removable film layers at a temperature of at least about <NUM> degrees Celsius;
cutting the base film layer (<NUM>), the first release layer (<NUM>) and the first removable film layer (<NUM>) in the shape of the perimeter (<NUM>) of the base film layer (<NUM>); and
cutting the first removable film layer (<NUM>) in the shape of the perimeter (<NUM> of the first removable film layer (<NUM>).