Patent Description:
<CIT> describes a method of making a thermoplastic film, uniformly stretching the thermoplastic film to control the thickness thereof and imparting desirable mechanical properties thereto.

<CIT> describes an elastomeric film comprising a layer comprising at least one olefin-based elastomeric polymer, at least one draw down polymer, wherein said elastomeric film has a basis weight of no more than about <NUM> gsm and a permanent set of no more than about <NUM>% after recovery from being stretched to <NUM>% of its original size.

<CIT> describes breathable films prepared from melt embossed polyolefin/filler precursor films.

<CIT> describes antibacterial microporous films and a high speed method of making them.

<CIT> describes a process for the production of an air-permeable film which comprises stretching a film made of a composition comprising a polyolefin resin and an inorganic filler.

<CIT> describes gas-permeable but liquid-impermeable polyolefin microporous films.

<CIT> describes multilayer breathable microporous films with reinforced impermeability to liquid.

<CIT> describes a breathable, elastic film/support layer laminate including a thermoplastic elastomer film sheet of a thermoplastic elastomer and a filled semi crystalline predominantly linear polymer.

<CIT> describes coextruded, elastomeric breathable films for use in comfortable garments and personal care products.

The present invention provides a process for making a microporous breathable film comprising the steps of.

According to the present disclosure, a microporous breathable film is made using a manufacturing process. The manufacturing process comprises the steps of extruding a composition to form a molten web, casting the molten web to form a quenched film, and stretching the quenched film to form the microporous breathable film.

In illustrative embodiments, the composition extruded to form the molten web comprises a polyolefin and an inorganic filler. The quenched film is formed by casting the molten web against a surface of a chill roll using a vacuum box and/or blowing air (e.g., an air knife and/or an air blanket).

Also described herein is a microporous breathable film comprising a polyolefin and an inorganic filler dispersed in the polyolefin has a basis weight of less than about <NUM> gsm. The microporous breathable film also has a Dart Impact Strength of at least about <NUM> grams.

In illustrative embodiments, a multi-layer breathable barrier film comprises at least one microporous breathable film layer according to the present disclosure and at least one moisture-permeable barrier layer. The at least one moisture-permeable barrier layer comprises a hygroscopic polymer.

In illustrative embodiments, a personal hygiene product comprises at least one inner microporous breathable film and at least one outer non-woven layer. The at least one inner microporous breathable film is configured to contact skin and/or clothing of a user of the personal hygiene product.

Additional features of the present disclosure will become apparent to those skilled in the art upon consideration of illustrative embodiments exemplifying the best mode of carrying out the disclosure as presently perceived.

A first embodiment of a microporous breathable film <NUM> in accordance with the present disclosure is shown, for example, in <FIG>. Microporous breathable film <NUM> includes a thermoplastic polymer <NUM> and a solid filler <NUM> dispersed in the thermoplastic polymer <NUM>. In some embodiments, the microporous breathable film <NUM> includes a combination of two or more thermoplastic polymers <NUM> and/or a combination of two or more solid fillers <NUM>. As shown in <FIG>, the microporous breathable film <NUM> includes an interconnected network of micropores <NUM> formed in the thermoplastic polymer resin <NUM>. On average, the micropores <NUM> are smaller in size than the size of a typical water droplet but larger in size than a water vapor molecule. As a result, the micropores <NUM> permit the passage of water vapor but minimize or block the passage of liquid water. Two representative pathways for the transmission of water vapor through the microporous breathable film <NUM> are shown by the dashed lines <NUM> and <NUM> in <FIG>.

A precursor film containing a thermoplastic polymer <NUM> and a solid filler <NUM> dispersed in the thermoplastic polymer <NUM> may be produced by either a cast film process or a blown film process. The film thus produced may then be stretched by one or more stretching processes. The stretching process moves (e.g., pulls) polymeric material away from the surface of solid filler dispersed therein, thereby forming the micropores <NUM>.

In one example, stretching may be achieved via machine direction (MD) orientation by a process analogous to that shown in simplified schematic form in <FIG>. For example, the film <NUM> shown in <FIG> may be passed between at least two pairs of rollers in the direction of an arrow <NUM>. In this example, first roller <NUM> and a first nip <NUM> run at a slower speed (V<NUM>) than the speed (V<NUM>) of a second roller <NUM> and a second nip <NUM>. The ratio of V<NUM>/V<NUM> determines the degree to which the film <NUM> is stretched. Since there may be enough drag on the roll surface to prevent slippage, the process may alternatively be run with the nips open. Thus, in the process shown in <FIG>, the first nip <NUM> and the second nip <NUM> are optional.

In another example, stretching may be achieved via transverse or cross-directional (CD) stretching by a process analogous to that shown in simplified schematic form in <FIG>. For example, the film <NUM> shown in <FIG> may be moved in the direction of the arrow <NUM> while being stretched sideways on a tenter frame in the directions of doubled-headed arrow <NUM>. The tenter frame includes a plurality of attachment mechanisms <NUM> configured for gripping the film <NUM> along its side edges.

In a further example, stretching may be achieved via intermeshing gears (IMG) stretching by a process analogous to the one shown in simplified schematic form in <FIG>. For example, a film <NUM> may be moved between a pair of grooved or toothed rollers as shown in <FIG> in the direction of arrow <NUM>. In one example, the first toothed roller <NUM> may be rotated in a clockwise direction while the second toothed roller <NUM> may be rotated in a counterclockwise direction. At each point at which one or more teeth of the rollers <NUM> and <NUM> contact the film <NUM>, localized stresses may be applied that stretch the film <NUM> and introduce interconnecting micropores therein analogous to the micropores <NUM> shown in <FIG>. By the use of IMG stretching, the film <NUM> may be stretched in the machine direction (MD), the cross direction (CD), at oblique angles to the MD, or in any combination thereof.

A precursor film containing a thermoplastic polymer <NUM> and a solid filler <NUM> dispersed in the polymer <NUM> that is stretched to form a microporous breathable film <NUM> in accordance with the present disclosure may be prepared by mixing together the thermoplastic polymer <NUM> (or a combination of thermoplastic polymers <NUM>), the solid filler <NUM>, and any optional components until blended, heating the mixture, and then extruding the mixture to form a molten web. A suitable film-forming process may be used to form a precursor film en route to forming a microporous breathable film. For example, the precursor film may be manufactured by casting or extrusion using blown-film, co-extrusion, or single-layer extrusion techniques and/or the like. In one example, the precursor film may be wound onto a winder roll for subsequent stretching in accordance with the present disclosure. In another example, the precursor film may be manufactured in-line with a film stretching apparatus such as shown in one or more of <FIG>.

In addition to containing one or more thermoplastic polymers and solid filler, the precursor film may also contain other optional components to improve the film properties or processing of the film. Representative optional components include, but are not limited to, anti-oxidants (e.g., added to prevent polymer degradation and/or to reduce the tendency of the film to discolor over time) and processing aids (e.g., added to facilitate extrusion of the precursor film). In one example, the amount of one or more anti-oxidants in the precursor film is less than about <NUM>% by weight of the film and the amount of one or more processing aids is less than about <NUM>% by weight of the film. Additional optional additives include but are not limited to whitening agents (e.g., titanium dioxide), which may be added to increase the opacity of the film. In one example, the amount of one or more whitening agents is less than about <NUM>% by weight of the film. Further optional components include but are not limited to antiblocking agents (e.g., diatomaceous earth) and slip agents (e.g. erucamide a. erucylamide), which may be added to allow film rolls to unwind properly and to facilitate secondary processing (e.g., diaper making). In one example, the amount of one or more antiblocking agents and/or one or more slip agents is less than about <NUM>% by weight of the film. Further additional optional additives include but are not limited to scents, deodorizers, pigments other than white, noise reducing agents, and/or the like, and combinations thereof. In one example, the amount of one or more scents, deodorizers, pigments other than white, and/or noise reducing agents is less than about <NUM>% by weight of the film.

Prior to stretching, the precursor film may have an initial basis weight of less than about <NUM> grams per square meter (gsm). In one example, the precursor film has an initial basis weight of less than about <NUM> gsm. The precursor film may be a monolayer film, in which case the entire precursor film comprises the thermoplastic polymer (or combination of thermoplastic polymers) and solid filler (or combination of solid fillers). In another example, the precursor film may be a multilayer film as suggested in <FIG>.

In one example, a microporous breathable film <NUM> in accordance with the present disclosure is formed via a blown film process. In another example, a microporous breathable film <NUM> in accordance with the present disclosure is formed via a cast film process. The cast film process involves the extrusion of molten polymers through an extrusion die to form a thin film. The film is pinned to the surface of a chill roll with an air knife, an air blanket, and/or a vacuum box.

In illustrative embodiments, a process for making a microporous breathable film <NUM> in accordance with the present disclosure includes (a) extruding a composition containing a thermoplastic polymer <NUM> and a solid filler <NUM> to form a molten web, (b) casting the molten web against a surface of a chill roll using an air knife, an air blanket, a vacuum box, or a combination thereof to form a quenched film, and (c) stretching the quenched film to form the microporous breathable film <NUM>.

It has been discovered that by using a vacuum box, blowing air (e.g., an air knife and/or an air blanket), or a vacuum box in combination with blowing air to cast the molten web against a chill roll in accordance with the present disclosure, microporous breathable films <NUM> exhibiting surprisingly and unexpectedly improved properties as compared to other microporous breathable films may be prepared. As further described below, these properties may include reduced basis weight, increased Dart Impact Strength, increased strain at peak machine direction, reduced alcohol penetration as measured by Pressure Penetration Through a Fabric (PPT) testing, reduced bonding force needed to achieve a destruct bond in ultrasonic sealing, and/or the like, and combinations thereof.

In one example, the molten web is cast against the surface of the chill roll under negative pressure using a vacuum box as shown in simplified schematic form in <FIG>. A vacuum box works by evacuating air between the film and the surface of the chill roll. For example, as shown in <FIG>, a film <NUM> is extruded from an extrusion die <NUM> in the direction of arrow <NUM> and quenched from the molten state with a vacuum box <NUM>. The vacuum box <NUM> draws a vacuum behind the molten web <NUM> in the direction of arrow <NUM> to draw the film <NUM> down onto the chill roll <NUM>. The vacuum drawn in the direction of arrow <NUM> removes the entrained air between the surface of the chill roll <NUM> and the film <NUM>. The vacuum box process is not subject to draw resonance for high molecular weight polymers that would tend to extrude unstable thickness in a nipped quench process due to the draw resonance phenomenon.

When a vacuum box <NUM> is used, the molten polymer may exit the die <NUM> and hit the chill roll <NUM> within a smaller distance than in an embossed process. For example, in some embodiments, the melt curtain is configured to hit the chill roll <NUM> within a distance of less than about <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM> inches, <NUM>, inches, <NUM> inches, or <NUM> inch. In illustrative embodiments, the melt curtain is configured to exit the die and hit the roll within a distance of less than about <NUM> inches and, in some examples, within a distance of about or less than <NUM> inch. One advantage of reducing the distance between the die <NUM> and the roll surface <NUM> as compared to in a nipped quench process is that smaller distances are less susceptible to the phenomenon of neck-in. Neck-in refers to a reduction in width of the molten web that occurs as the web leaves the die. By drawing the film <NUM> onto a surface of the chill roll <NUM> over a short distance as shown in <FIG>, the vacuum box <NUM> may enhance web cooling, facilitate higher line speeds, reduce film neck-in, and/or reduce drag at the lip exit.

In another example, the molten web is cast against the surface of the chill roll under positive pressure using an air knife or air blanket, as shown in simplified schematic form in <FIG>. An air knife works to promote web quenching by gently blowing a high-velocity, low-volume air curtain over the molten film, thereby pinning the molten film to the chill roll for solidification. For example, as shown in <FIG>, a film <NUM> is extruded from an extrusion die <NUM> in the direction of arrow <NUM> and quenched from the molten state with an air knife <NUM> blowing an air curtain over the molten film <NUM>, thereby pinning the molten web <NUM> against a surface of the chill roll <NUM>. An air blanket (a. "soft box") works similarly to an air knife and promotes web quenching by gently blowing an air curtain over the molten film. However, in the case of an air blanket, the air curtain is low velocity and high volume.

In a further example, the molten web is cast against the surface of the chill roll under a combination of negative pressure from a vacuum box, as shown in <FIG>, and positive pressure from an air knife, as shown in <FIG>. In illustrative embodiments, in the casting of the molten web against a surface of the chill roll, an exit temperature of cooling fluid passing through the chill roll is between about <NUM> degrees Fahrenheit and about <NUM> degrees Fahrenheit and, in some examples, between about <NUM> degrees Fahrenheit and about <NUM> degrees Fahrenheit.

The thermoplastic polymer <NUM> (or combination of thermoplastic polymers <NUM>) used to make a microporous breathable film <NUM> in accordance with the present disclosure is not restricted, and may include all manner of thermoplastic polymers capable of being stretched and of forming micropores. In illustrative embodiments, the thermoplastic polymer is a polyolefin, including but not limited to homopolymers, copolymers, terpolymers, and/or blends thereof.

Representative polyolefins that may be used in accordance with the present disclosure include but are not limited to low density polyethylene (LDPE), high density polyethylene (HDPE), linear low density polyethylene (LLDPE), ultra-low density polyethylene (ULDPE), polypropylene, ethylene-propylene copolymers, polymers made using a single-site catalyst, ethylene maleic anhydride copolymers (EMAs), ethylene vinyl acetate copolymers (EVAs), polymers made using Zeigler-Natta catalysts, styrene-containing block copolymers, and/or the like, and combinations thereof. Methods for manufacturing LDPE are described in <NPL>) and in <CIT>, both of which are incorporated by reference herein, except that in the event of any inconsistent disclosure or definition from the present specification, the disclosure or definition herein shall be deemed to prevail.

ULDPE may be produced by a variety of processes, including but not limited to gas phase, solution and slurry polymerization as described in<NPL>), incorporated by reference above, except that in the event of any inconsistent disclosure or definition from the present specification, the disclosure or definition herein shall be deemed to prevail.

ULDPE may be manufactured using a Ziegler-Natta catalyst, although a number of other catalysts may also be used. For example, ULDPE may be manufactured with a metallocene catalyst. Alternatively, ULDPE may be manufactured with a catalyst that is a hybrid of a metallocene catalyst and a Ziegler-Natta catalyst. Methods for manufacturing ULDPE are also described in <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, and <CIT>, each of which is incorporated by reference herein in its entirety, except that in the event of any inconsistent disclosure or definition from the present specification, the disclosure or definition herein shall be deemed to prevail. The density of ULDPE is achieved by copolymerizing ethylene with a sufficient amount of one or more monomers. In illustrative embodiments, the monomers are selected from <NUM>-butene, <NUM>-hexene, <NUM>-methyl-<NUM>-pentene, <NUM>-octene, and combinations thereof. Methods for manufacturing polypropylene are described in <NPL>), which is incorporated herein by reference, except that in the event of any inconsistent disclosure or definition from the present specification, the disclosure or definition herein shall be deemed to prevail.

In illustrative embodiments, a polyolefin for use in accordance with the present disclosure includes polyethylene, polypropylene, or a combination thereof. In one example, the polyethylene includes linear low density polyethylene which, in some embodiments, includes a metallocene polyethylene. In another example, the polyethylene includes a combination of linear low density polyethylene and low density polyethylene. In a further example, the polyolefin consists essentially of only linear low density polyethylene.

In addition to thermoplastic polymer (e.g., polyolefin), a composition to be extruded in accordance with the present disclosure further includes a solid filler. The solid filler is not restricted, and may include all manner of inorganic or organic materials that are (a) non-reactive with thermoplastic polymer, (b) configured for being uniformly blended and dispersed in the thermoplastic polymer, and (c) configured to promote a microporous structure within the film when the film is stretched. In illustrative embodiments, the solid filler includes an inorganic filler.

Representative inorganic fillers for use in accordance with the present disclosure include but are not limited to sodium carbonate, calcium carbonate, magnesium carbonate, barium sulfate, magnesium sulfate, aluminum sulfate, magnesium oxide, calcium oxide, alumina, mica, talc, silica, clay (e.g., non-swellable clay), glass spheres, titanium dioxide, aluminum hydroxide, zeolites, and a combination thereof. In illustrative embodiments, the inorganic filler includes an alkali metal carbonate, an alkaline earth metal carbonate, an alkali metal sulfate, an alkaline earth metal sulfate, or a combination thereof. In one example, the inorganic filler includes calcium carbonate.

In another example, the solid filler includes a polymer (e.g., high molecular weight high density polyethylene, polystyrene, nylon, blends thereof, and/or the like). The use of polymer fillers creates domains within the thermoplastic polymer matrix. These domains are small areas, which may be spherical, where only the polymer filler is present as compared to the remainder of the thermoplastic matrix where no polymer filler is present. As such, these domains act as particles.

The solid filler <NUM> provided in a composition to be extruded in accordance with the present disclosure may be used to produce micropores <NUM> of film <NUM>, as shown in <FIG>. The dimensions of the solid filler <NUM> particles may be varied based on a desired end use (e.g., the desired properties of the microporous breathable film <NUM>). In one example, the average particle size of a solid filler particle ranges from about <NUM> microns to about <NUM> microns. In illustrative embodiments, the average particle size ranges from about <NUM> micron to about <NUM> microns and, in some examples, from about <NUM> micron to about <NUM> microns. The average particle size may be one of several different values or fall within one of several different ranges. For example, it is within the scope of the present disclosure to select an average particle size of the solid filler to be one of the following values: about <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns. <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, or <NUM> microns.

It is also within the scope of the present disclosure for the average particle size of the solid filler <NUM> provided in a composition to be extruded in accordance with the present disclosure to fall within one of many different ranges. In a first set of ranges, the average particle size of the solid filler <NUM> is in one of the following ranges: about <NUM> microns to <NUM> microns, <NUM> microns to <NUM> microns, <NUM> microns to <NUM> microns, <NUM> microns to <NUM> microns, <NUM> microns to <NUM> microns, <NUM> microns to <NUM> microns, <NUM> microns to <NUM> microns, <NUM> microns to <NUM> microns, <NUM> microns to <NUM> microns, <NUM> microns to <NUM> microns, <NUM> microns to <NUM> microns, <NUM> microns to <NUM> microns, and <NUM> microns to <NUM> microns. In a second set of ranges, the average particle size of the solid filler <NUM> is in one of the following ranges: about <NUM> microns to <NUM> microns, <NUM> microns to <NUM> microns, <NUM> microns to <NUM> microns, <NUM> microns to <NUM> microns, <NUM> microns to <NUM> microns, <NUM> microns to <NUM> microns, <NUM> microns to <NUM> microns, <NUM> microns to <NUM> microns, <NUM> microns to <NUM> microns, and <NUM> microns to <NUM> microns. In a third set of ranges, the average particle size of the solid filler <NUM> is in one of the following ranges: about <NUM> microns to <NUM> microns, <NUM> microns to <NUM> microns, <NUM> microns to <NUM> microns, <NUM> microns to <NUM> microns, <NUM> microns to <NUM> microns, <NUM> microns to <NUM> microns, <NUM> microns to <NUM> microns, <NUM> microns to <NUM> microns, <NUM> microns to <NUM> microns, and <NUM> microns to <NUM> microns.

In illustrative embodiments, the amount of solid filler used in accordance with the present disclosure includes from about <NUM>% by weight to about <NUM>% by weight of the composition to be extruded, quenched film formed from the extruded composition, and/or microporous breathable film formed from the quenched film. In further illustrative embodiments, the amount of solid filler used in accordance with the present disclosure includes from about <NUM>% by weight to about <NUM>% by weight of the composition to be extruded, quenched film formed from the extruded composition, and/or microporous breathable film formed from the quenched film. Although amounts of filler outside this range may also be employed, an amount of solid filler that is less than about <NUM>% by weight may not be sufficient to impart uniform breathability to a film. Conversely, amounts of filler greater than about <NUM>% by weight may be difficult to blend with the polymer and may cause a loss in strength in the final microporous breathable film.

The amount of solid filler <NUM> may be varied based on a desired end use (e.g., the desired properties of the microporous breathable film <NUM>). In one example, the amount of solid filler <NUM> ranges from about <NUM>% to about <NUM>% by weight of the composition, quenched film, and/or microporous breathable film. In another example, the amount of solid filler <NUM> ranges from about <NUM>% to about <NUM>% by weight of the composition, quenched film, and/or microporous breathable film. The amount of solid filler <NUM> may be one of several different values or fall within one of several different ranges. For example, it is within the scope of the present disclosure to select an amount of the solid filler <NUM> to be one of the following values: about <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, or <NUM>% by weight of the composition, quenched film, and/or microporous breathable film.

It is also within the scope of the present disclosure for the amount of the solid filler <NUM> to fall within one of many different ranges. In a first set of ranges, the amount of the solid filler <NUM> is in one of the following ranges: about <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, and <NUM>% to <NUM>% by weight of the composition, quenched film, and/or microporous breathable film. In a second set of ranges, the amount of the solid filler is in one of the following ranges: about <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, and <NUM>% to <NUM> % by weight of the composition, quenched film, and/or microporous breathable film. In a third set of ranges, the amount of the solid filler is in one of the following ranges: about <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, and <NUM>% to <NUM>% by weight of the composition, quenched film, and/or microporous breathable film.

Although filler loading may be conveniently expressed in terms of weight percentages, the phenomenon of microporosity may alternatively be described in terms of volume percent of filler relative to total volume. By way of illustration, for calcium carbonate filler having a specific gravity of <NUM>/cc and a polymer having a specific gravity of about <NUM>, <NUM>% by weight CaCO<NUM> corresponds to a filler loading of about <NUM>% by volume {(<NUM>/<NUM>)/(<NUM>/<NUM> + <NUM>/<NUM>)}. Similarly, the <NUM> weight percent upper end of the range described above corresponds to about <NUM>% by volume of CaCO<NUM>. Thus, the amount of filler may be adjusted to provide comparable volume percentages for alternative solid fillers that have different (e.g., unusually low or high) specific gravities as compared to calcium carbonate.

In some embodiments, to render the solid filler particles free-flowing and to facilitate their dispersion in the polymeric material, the filler particles may be coated with a fatty acid and/or other suitable processing acid. Representative fatty acids for use in this context include but are not limited to stearic acid or longer chain fatty acids.

The type of stretching used to transform a quenched film into a microporous breathable film <NUM> in accordance with the present disclosure comprises CD-IMG stretching. All manner of stretching processes-and combinations of stretching processes-that are capable of moving (e.g., pulling) polymeric material <NUM> away from the surface of solid filler <NUM> dispersed therein in order to form micropores <NUM>-are contemplated for use. In some examples, the stretching includes MD stretching. In further examples, the stretching includes MD IMG stretching. In still further examples, the stretching includes cold draw. Also described herein, the stretching may include a combination of two or more different types of stretching including but not limited to MD stretching, CD IMG stretching, MD IMG stretching, cold draw, and/or the like. In some examples, the stretching includes a combination of CD IMG stretching and cold draw (which, in some embodiments, is performed subsequently to the CD IMG stretching).

The type of stretching used to transform a quenched film into a microporous breathable film <NUM> in accordance with the present disclosure includes CD IMG stretching. In addition, in illustrative embodiments, at least a portion of the stretching is performed at a temperature above ambient temperature. In one example, at least a portion of the stretching is performed at a temperature of between about <NUM> degrees Fahrenheit and about <NUM> degrees Fahrenheit.

In illustrative embodiments, a process for making a microporous breathable film <NUM> in accordance with the present disclosure further includes (d) annealing the microporous breathable film <NUM>. In one example, the annealing is performed at a temperature of between about <NUM> degrees Fahrenheit and about <NUM> degrees Fahrenheit.

In illustrative embodiments, as noted above, a microporous breathable film <NUM> prepared in accordance with the present disclosure (e.g., by using a vacuum box and/or air knife to cast a molten web containing a polyolefin and an inorganic filler against a chill roll) may have reduced basis weight, increased Dart Impact Strength, increased strain at peak machine direction, reduced alcohol penetration as measured by PPT testing, and/or reduced bonding force needed to achieve a destruct bond in ultrasonic sealing, as compared to conventional microporous breathable films.

The basis weight of a microporous breathable film <NUM> in accordance with the present disclosure may be varied based on a desired end use (e.g., the desired properties and/or applications of the microporous breathable film). According to the invention, the basis weight is less than <NUM> gsm. Lower basis weights minimize material cost as well as maximize consumer satisfaction (e.g., a thinner film may provide increased comfort to the user of a personal hygiene product that includes the film). The basis weight of a microporous breathable film <NUM> in accordance with the present disclosure may be one of several different values or fall within one of several different ranges. For example, it is within the scope of the present disclosure to select a basis weight to be one of the following values: <NUM> gsm, <NUM> gsm, <NUM> gsm, <NUM> gsm, <NUM> gsm, <NUM> gsm, or <NUM> gsm.

In illustrative embodiments, a microporous breathable film <NUM> in accordance with the present disclosure exhibits a greater Dart Impact Strength than conventional microporous breathable films of similar basis weight. The basis weight of a microporous breathable film <NUM> in accordance with the present disclosure may be varied based on a desired Dart Impact Strength.

The Dart Impact Strength of a microporous breathable film <NUM> in accordance with the present disclosure may be one of several different values or fall within one of several different ranges. For example, for a microporous breathable film <NUM> having a basis weight of less than <NUM> gsm, <NUM> gsm, <NUM> gsm, <NUM> gsm, or <NUM> gsm-it is within the scope of the present disclosure to select a Dart Impact Strength to be greater than or equal to one of the following values: about <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, <NUM> grams, or <NUM> grams.

It is also within the scope of the present disclosure for the Dart Impact Strength of the microporous breathable film <NUM> to fall within one of many different ranges. In a first set of ranges, the Dart Impact Strength for a microporous breathable film having a basis weight of less than about <NUM> gsm-in some embodiments, less than about <NUM> gsm, <NUM> gsm, <NUM> gsm, <NUM> gsm, <NUM> gsm, or <NUM> gsm-is in one of the following ranges: about <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, and <NUM> grams to <NUM> grams. In a second set of ranges, the Dart Impact Strength for a microporous breathable film <NUM> having a basis weight of less than about <NUM> gsm-in some embodiments, less than about <NUM> gsm, <NUM> gsm, <NUM> gsm, <NUM> gsm, <NUM> gsm, or <NUM> gsm-is in one of the following ranges: about <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, and <NUM> grams to <NUM> grams. In a third set of ranges, the Dart Impact Strength for a microporous breathable film <NUM> having a basis weight of less than about <NUM> gsm-in some embodiments, less than about <NUM> gsm, <NUM> gsm, <NUM> gsm, <NUM> gsm, <NUM> gsm, or <NUM> gsm-is in one of the following ranges: about <NUM> grams to about <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, <NUM> grams to <NUM> grams, and <NUM> grams to <NUM> grams.

In illustrative embodiments, a microporous breathable film <NUM> in accordance with the present disclosure exhibits a greater strain at peak machine direction than conventional microporous breathable films of similar basis weight. The basis weight of a microporous breathable film <NUM> in accordance with the present disclosure may be varied based on a desired strain at peak machine direction.

The strain at peak machine direction of a microporous breathable film <NUM> in accordance with the present disclosure may be one of several different values or fall within one of several different ranges. For example, for a microporous breathable film having a basis weight of less than <NUM> gsm, <NUM> gsm, <NUM> gsm, <NUM> gsm, or <NUM> gsm-it is within the scope of the present disclosure to select a strain at peak machine direction to be greater than or equal to one of the following values: <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, or <NUM>%.

It is also within the scope of the present disclosure for the strain at peak machine direction of the microporous breathable film <NUM> to fall within one of many different ranges. In a first set of ranges, the strain at peak machine direction for a microporous breathable film having a basis weight of less than <NUM> gsm, <NUM> gsm, <NUM> gsm, <NUM> gsm, or <NUM> gsm-is in one of the following ranges: <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, and <NUM>% to <NUM>%. In another set of ranges, the strain at peak machine direction for a microporous breathable film <NUM> having a basis weight of less than <NUM> gsm, <NUM> gsm, <NUM> gsm, <NUM> gsm, or <NUM> gsm-is in one of the following ranges: <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, and <NUM>% to <NUM>%.

In illustrative embodiments, a microporous breathable film <NUM> in accordance with the present disclosure exhibits reduced alcohol penetration as measured by Pressure Penetration Through a Fabric (PPT) testing. In PPT testing, the imperviousness of a film is quantified in relation to the degree to which a dye-containing alcohol penetrates the film. The amount of alcohol penetration may, in turn, be measured as the percentage of blotter paper surface area that contains red blots after a nonwoven material saturated with red dye is overlaid on a film and a weight is applied. The PPT test is further described in the Examples section below as well as in <CIT>, the entire contents of which are incorporated by reference herein, except that in the event of any inconsistent disclosure or definition from the present specification, the disclosure or definition herein shall be deemed to prevail.

The basis weight of a microporous breathable film <NUM> in accordance with the present disclosure may be varied based on a desired degree of alcohol penetration of the film as measured by PPT testing. In one example, a microporous breathable film <NUM> in accordance with the present disclosure has a basis weight of less than about <NUM> gsm and an alcohol penetration of less than about <NUM>% as measured by PPT testing.

The alcohol penetration of a microporous breathable film <NUM> in accordance with the present disclosure as measured by PPT testing may be one of several different values or fall within one of several different ranges. For example, for a microporous breathable film having a basis weight of less than <NUM> gsm, <NUM> gsm, <NUM> gsm, or <NUM> gsm-it is within the scope of the present disclosure to select an alcohol penetration of less than or equal to one of the following values: about <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, or <NUM>%.

It is also within the scope of the present disclosure for the alcohol penetration of a microporous breathable film <NUM> in accordance with the present disclosure as measured by PPT testing to fall within one of many different ranges. In a first set of ranges, the alcohol penetration as measured by PPT testing for a microporous breathable film having a basis weight of less than <NUM> gsm, <NUM> gsm, <NUM> gsm, or <NUM> gsm-is in one of the following ranges: about <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, and <NUM>% to <NUM>%. In a second set of ranges, the alcohol penetration as measured by PPT testing for a microporous breathable film having a basis weight of less than <NUM> gsm, <NUM> gsm, <NUM> gsm, or <NUM> gsm-is in one of the following ranges: about <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, and <NUM> to <NUM>%. In a third set of ranges, the alcohol penetration as measured by PPT testing for a microporous breathable film having a basis weight of less than <NUM> gsm, <NUM> gsm, <NUM> gsm, or <NUM> gsm-is in one of the following ranges: about <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, and <NUM>% to <NUM>%.

In some embodiments, a microporous breathable film <NUM> in accordance with the present disclosure is essentially impervious to one or more of water, methyl alcohol, ethyl alcohol, body fluids (e.g., blood, body fats and oils, saliva, menses, feces, urine, and/or the like), and surfactant-containing disinfectants. In some embodiments, the microporous breathable film <NUM> in accordance with the present disclosure has an isopropyl alcohol penetration of less than about <NUM>%, in some embodiments less than about <NUM>%, and in some embodiments less than about <NUM>%. In some embodiments, a microporous breathable film <NUM> in accordance with the present disclosure is essentially impervious to alcohol (e.g., isopropyl alcohol).

In illustrative embodiments, a microporous breathable film <NUM> in accordance with the present disclosure exhibits reduced bonding force to achieve a destruct bond. The "destruct bond" refers to a strong bond between two materials (e.g., a microporous breathable film <NUM> or multi-layer breathable barrier film <NUM> in accordance with the present disclosure bonded to a nonwoven layer), such that an attempt to separate the two materials (e.g., by pulling) damages one of the materials (e.g., the bonding agent is stronger than the materials that are bonded together).

The basis weight of a microporous breathable film <NUM> in accordance with the present disclosure may be varied based on a desired bonding force. In one example, a microporous breathable film <NUM> in accordance with the present disclosure has a basis weight of less than about <NUM> gsm and a bonding force less than about <NUM> Newtons for a <NUM>-mm wide horn.

The bonding force of a microporous breathable film <NUM> in accordance with the present disclosure may be one of several different values or fall within one of several different ranges. For example, for a microporous breathable film having a basis weight of less than <NUM> gsm, <NUM> gsm, <NUM> gsm, or <NUM> gsm -it is within the scope of the present disclosure to select a bonding force to be less than or equal to one of the following values for a <NUM>-mm wide horn: about <NUM> Newtons, <NUM> Newtons, <NUM> Newtons, <NUM> Newtons, <NUM> Newtons, <NUM> Newtons, <NUM> Newtons, <NUM> Newtons, <NUM> Newtons, <NUM> Newtons, <NUM> Newtons, <NUM> Newtons, <NUM> Newtons, <NUM> Newtons, <NUM> Newtons, <NUM> Newtons, or <NUM> Newtons.

It is also within the scope of the present disclosure for the bonding force of a microporous breathable film <NUM> in accordance with the present disclosure to fall within one of many different ranges. In a first set of ranges, the bonding force for a microporous breathable film having a basis weight of less than or equal to about <NUM> gsm-in some embodiments, less than <NUM> gsm, <NUM> gsm, <NUM> gsm, or <NUM> gsm-is in one of the following ranges for a <NUM>-mm wide horn: about <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, and <NUM> Newtons to <NUM> Newtons. In a second set of ranges, the bonding force for a microporous breathable film having a basis weight of less than <NUM> gsm, <NUM> gsm, <NUM> gsm, or <NUM> gsm-is in one of the following ranges for a <NUM>-mm wide horn: about <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, and <NUM> Newtons to <NUM> Newtons. In a third set of ranges, the bonding force for a microporous breathable film having a basis weight of less than or equal to about <NUM> gsm-in some embodiments, less than <NUM> gsm, <NUM> gsm, <NUM> gsm, or <NUM> gsm-is in one of the following ranges for a <NUM>-mm wide horn: about <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, <NUM> Newtons to <NUM> Newtons, and <NUM> Newtons to <NUM> Newtons.

In some embodiments, as described above, the present disclosure provides a monolayer microporous breathable film <NUM>. In other embodiments, the present disclosure also provides a multi-layer microporous breathable film (not shown). In one example, a multilayer microporous breathable film includes a core layer and one or more outer skin layers adjacent to the core layer. The core layer may resemble the film <NUM> shown in <FIG> and include a thermoplastic polymer (or combination of thermoplastic polymers) and a solid filler (or combination of solid fillers) dispersed therein, whereas the one or more outer skin layers may have either the same composition as the core or a different composition than the core. In one example, the skin layers may be independently selected from compositions designed to minimize the levels of volatiles building up on the extrusion die. Upon subsequent stretching, the core layer becomes microporous and breathable, while the skin layers may or may not be breathable depending upon whether or not they contain a solid filler. The thickness and composition of one or more skin layers in a multilayer version of a microporous breathable film are selected so that, when the precursor film is subsequently stretched, the resulting film is still breathable. In one example, a pair of skin layers sandwiching a core layer are relatively thin and together account for no more than about <NUM>% of the total film thickness. In some embodiments, regardless of whether or not a skin layer contains a solid filler, the skin layer may still be breathable. For example, the skin layer may include one or more discontinuities that are introduced during the stretching process. The likelihood of discontinuities forming in a skin layer may increase as the thickness of the skin layer subjected to stretching decreases.

In one example, a multi-layer microporous breathable films in accordance with the present disclosure may be manufactured by feed block coextrusion. In another example, a multi-layer microporous breathable films in accordance with the present disclosure may be made by blown film (tubular) coextrusion. Methods for feed block and blown film extrusion are described in<NPL>), which is incorporated herein by reference, except that in the event of any inconsistent disclosure or definition from the present specification, the disclosure or definition herein shall be deemed to prevail. Methods for film extrusion are also described in <CIT>, the entire contents of which are likewise incorporated by reference herein, except that in the event of any inconsistent disclosure or definition from the present specification, the disclosure or definition herein shall be deemed to prevail.

In some embodiments, as described above, the present disclosure provides microporous breathable films (e.g., mono-layer or multi-layer). In other embodiments, the present disclosure further provides multi-layer breathable barrier films.

A multi-layer breathable barrier film <NUM> is shown, for example, in <FIG>. The multi-layer breathable barrier film <NUM> shown in <FIG> includes at least one microporous breathable film layer <NUM> and at least one monolithic moisture-permeable barrier layer <NUM>. The monolithic moisture-permeable barrier layer <NUM> includes a hygroscopic polymer. In illustrative embodiments, the monolithic moisture-permeable barrier layer <NUM> is a monolithic hydrophilic polymer. Monolithic hydrophilic polymers are able to transmit moisture without the additional need of fillers and stretching. The mechanism of breathability in a monolithic hydrophilic polymer is accomplished by absorption and desorption of moisture.

The at least one microporous breathable film layer <NUM> in <FIG> is analogous to the microporous breathable film <NUM> shown in <FIG>, and may be prepared by a process analogous to that described above. In one example, the at least one microporous breathable film layer <NUM> includes a polyolefin and an inorganic filler dispersed in the polyolefin. Also described herein, the at least one microporous breathable film layer <NUM> may have a basis weight of less than about <NUM> gsm and a Dart Impact Strength of greater than about <NUM> grams.

In illustrative embodiments, as shown in <FIG>, the multi-layer breathable barrier film <NUM> further includes at least at least one additional microporous breathable film layer <NUM>. The second microporous breathable film layer <NUM> may be the same as or different than the first microporous breathable film layer <NUM>. For example, the first microporous breathable film layer <NUM> and the second microporous breathable film layer <NUM> may differ from each other in thickness, breathability, pore size, and/or thermoplastic composition.

The at least one additional microporous breathable film layer <NUM>-similar to the at least one microporous breathable film layer <NUM>-is analogous to the microporous breathable film <NUM> shown in <FIG>, and may be prepared by a process analogous to that described above. In one example, the at least one additional microporous breathable film layer <NUM> includes a polyolefin and an inorganic filler dispersed in the polyolefin. Also described herein, the at least one additional microporous breathable film layer <NUM> may have a basis weight of less than about <NUM> gsm and a Dart Impact Strength of greater than about <NUM> grams. In illustrative embodiments, as shown in <FIG>, the at least one monolithic moisture-permeable barrier layer <NUM> is disposed between the at least one microporous breathable film layer <NUM> and the at least one additional microporous breathable film layer <NUM> although other configurations may likewise be implemented.

The monolithic moisture-permeable barrier layer <NUM> shown in <FIG> provides an internal viral and alcohol barrier layer and-unlike microporous breathable film layer <NUM> and microporous breathable film layer <NUM>-may be unfilled or substantially unfilled (e.g., contain an amount of solid filler that does not result in the creation of micropores as a result of stretching). In illustrative embodiments, the monolithic moisture-permeable barrier layer <NUM> contains a hygroscopic polymer-including but not limited to the hygroscopic polymers described in International Patent Publication No. <CIT>. The entire contents of International Patent Publication No.<CIT> are hereby incorporated by reference, except that in the event of any inconsistent disclosure or definition from the present specification, the disclosure or definition herein shall be deemed to prevail.

The monolithic moisture-permeable barrier layer <NUM> provides a barrier to viruses and to alcohol penetration. In one example, a tie layer (not shown) may be used to combine dissimilar layers (e.g., monolithic moisture-permeable barrier layer <NUM> and one or both of microporous breathable film layer <NUM> and microporous breathable film layer <NUM>). In another example, an adhesive may be blended in one or more of the adjacent dissimilar layers, thus avoiding potential loss in permeability arising from a continuous non-breathable tie layer.

In a further example, no tie resin is present in one, more than one, or any of the layers of a multi-layer film structure. While neither desiring to be bound by any particular theory nor intending to limit in any measure the scope of the appended claims or their equivalents, it is presently believed that in some embodiments, the use of a tie resin adhesive to keep layers from separating during manufacture and handling may be avoided inasmuch as unstretched lanes of a film (e.g., such as may be produced by CD IMG activation) fulfill the function of the tie resin and facilitate adjoining of layers. For embodiments in which no tie resin is present, there may be advantages in terms of cost savings since tie resins tend to be costly. In addition, tie resins are prone to gel formation during the extrusion process, which is generally undesirable.

The internal monolithic moisture-permeable barrier layer <NUM> may include a hygroscopic polymer. In illustrative embodiments, the hygroscopic polymer is selected from the group consisting of hygroscopic elastomers, polyesters, polyamides, polyetherester copolymers, polyetheramide copolymers, polyurethanes, polyurethane copolymers, poly(etherimide) ester copolymers, polyvinyl alcohols, ionomers, celluloses, nitrocelluloses, and/or the like, and combinations thereof. In some embodiments, the at least one monolithic moisture-permeable barrier layer <NUM> further includes an adhesive which, in some embodiments, includes polyethylene/acrylate copolymer, ethylene/methyl acrylate copolymer, acid-modified acrylate, anhydride-modified acrylate, ethylene vinyl acetate, acid/acrylate-modified ethylene vinyl acetate, anhydride-modified ethylene vinyl acetate, and/or the like, or a combination thereof. The monolithic moisture-permeable barrier layer <NUM> may be prepared from a hygroscopic polymer resin or from a combination of hygroscopic polymer resins and, optionally, from a blend of one or more hygroscopic polymer resins and one or more adhesives.

In one example, the internal monolithic moisture-permeable barrier layer <NUM> may constitute from about <NUM>% to about <NUM>% of the total thickness of the film <NUM>. In another example, the barrier layer <NUM> may constitute from about <NUM> % to about <NUM>% of the total thickness of the film <NUM>. In a further example, the barrier layer <NUM> may constitute from about <NUM>% to about <NUM>% of the total thickness of the film <NUM>. In some embodiments (not shown), the film <NUM> includes a plurality of monolithic moisture-permeable barrier layers <NUM>, and the above-described exemplary ranges of thickness percentages may be applied to the sum of the multiple barrier layers within the film. Multi-layer breathable barrier films <NUM> in accordance with the present disclosure may include one or more internal monolithic moisture-permeable barrier layers <NUM>, which may be contiguous with each other or with interposed microporous breathable layers such as microporous breathable layer <NUM> and microporous breathable layer <NUM>. In illustrative embodiments, one or more moisture-permeable barrier layers <NUM> provided in a multi-layer breathable barrier film <NUM> in accordance with the present disclosure, are monolithic and do not contain any fillers that provide sites for the development of micropores. However, monolithic moisture-permeable barrier layers may contain other additives to confer desired properties to the barrier layer.

Representative materials for the monolithic moisture-permeable barrier layer <NUM> include but are not limited to hygroscopic polymers such as ε-caprolactone (available from Solvay Caprolactones), polyether block amides (available from Arkema PEBAX), polyester elastomer (such as Dupont Hytrel or DSM Arnitel) and other polyesters, polyamides, celluloses (e.g., cellulose fibers), nitrocelluloses (e.g., nitrocellulose fibers), ionomers (e.g., ethylene ionomers), and/or the like, and combinations thereof. In one example, fatty acid salt-modified ionomers as described in the article entitled "<NPL>) may be used as a monolithic moisture-permeable barrier layer <NUM>. In some embodiments, sodium, magnesium, and/or potassium fatty acid salt-modified ionomers may be used to provide desirable water vapor transmission properties. In some embodiments, the monolithic moisture-permeable barrier layer <NUM> is selected from the group consisting of hygroscopic elastomers, polyesters, polyamides, polyetherester copolymers (e.g., a block polyetherester copolymer), polyetheramide copolymers (e.g., a block polyetheramide copolymer), polyurethanes, polyurethane copolymers, poly(etherimide) ester copolymers, polyvinyl alcohols, ionomers, celluloses, nitrocelluloses, and/or the like, and combinations thereof. In one example, copolyether ester block copolymers are segmented elastomers having soft polyether segments and hard polyester segments, as described in <CIT>. Representative copolyether ester block copolymers are sold by DuPont under the trade name HYTREL®. Representative copolyether amide polymers are copolyamides sold under the trade name PEBAX® by Atochem Inc. of Glen Rock, New Jersey. Representative polyurethanes are thermoplastic urethanes sold under the trade name ESTANE® by the B. Goodrich Company of Cleveland, Ohio. Representative copoly(etherimide) esters are described in <CIT>.

In some embodiments, the monolithic moisture-permeable barrier layer <NUM> may include or be blended with a thermoplastic resin. Representative thermoplastic resins that may be used for this purpose include but are not limited to polyolefins, polyesters, polyetheresters, polyamides, polyether amides, urethanes, and/or the like, and combinations thereof. In some embodiments, the thermoplastic polymer may include (a) a polyolefin, such as polyethylene, polypropylene, poly(i-butene), poly(<NUM>-butene), poly(i-pentene), poly(<NUM>-pentene), poly(<NUM>-methyl-<NUM>-pentene), poly(<NUM>-methyl-<NUM>-pentene), <NUM>,<NUM>-poly-<NUM>,<NUM>-butadiene, <NUM>,<NUM>-poly-<NUM>,<NUM>-butadiene, polyisoprene, polychloroprene, polyacrylonitrile, polyvinyl acetate, poly(vinylidene chloride), polystyrene, and/or the like, and combinations thereof; (b) a polyester such as poly(ethylene terephthalate), poly(butylenes)terephthalate, poly(tetramethylene terephthalate), poly(cyclohexylene-<NUM>,<NUM>-dimethylene terephthalate), poly(oxymethylene-<NUM>,<NUM>-cyclohexylenemethyleneoxyterephthaloyl), and/or the like, and combinations thereof; and (c) a polyetherester, such as poly(oxyethylene)-poly(butylene terephthalate), poly(oxytetramethylene)-poly(ethylene terephthalate), and/or the like, and combinations thereof; and/or (d) a polyamide, such as poly(<NUM>-aminocaproic acid), poly(,-caprolactam), poly(hexamethylene adipamide), poly(hexamethylene sebacamide), poly(<NUM><NUM> -aminoundecanoic acid), and/or the like, and combinations thereof.

In illustrative embodiments the hygroscopic polymer is a hygroscopic elastomer. A variety of additives may be added to the monolithic moisture-permeable barrier layer <NUM> to provide additional properties such as antimicrobial effects, odor control, static decay, and/or the like. One or more monolithic moisture-permeable barrier layers <NUM> is placed in the film <NUM> to impede the flow of liquids, liquid borne pathogens, viruses, and other microorganisms that may be carried by a liquid challenge.

One or more of the monolithic moisture-permeable barrier layers <NUM>, microporous breathable film layer <NUM>, and microporous breathable film layer <NUM> in the multi-layer breathable barrier film <NUM> may include one or more adhesives for adhering the internal monolithic moisture-permeable barrier layer <NUM> to contiguous layers to form the multi-layer film <NUM>. In one example, adhesive may be components suitable for adhering two or more layers together. In one example, adhesives are compatibilizing adhesives that increase the compatibility of the layers as well as adhering the layers to one another. The adhesives may be included in the resin or other extrudable material before extruding that resin into the monolithic moisture-permeable barrier layer <NUM>. Representative compatibilizing adhesives include but are not limited to polyethylene/acrylate copolymer, ethylene/methyl acrylate copolymer, acid-modified acrylate, anhydride-modified acrylate, ethylene vinyl acetate, acid/acrylate-modified ethylene vinyl acetate, anhydride-modified ethylene vinyl acetate, and/or the like, and combinations thereof. In one example, when one of the microporous breathable layer <NUM>, the microporous breathable layer <NUM> and the monolithic moisture-permeable barrier layer <NUM> includes an adhesive, the adhesive may have a relatively high methacrylate content (e.g., a methacrylate content of at least about <NUM>% to <NUM>%). In some embodiments, the internal monolithic moisture-permeable barrier layer <NUM> may be prepared from blends including up to about <NUM>% by weight adhesive and at least about <NUM>% by weight hygroscopic polymer.

In some embodiments, the hygroscopic polymer may be dried before it is extruded. Feeding pre-dried hygroscopic elastomer in small amounts to an extruder has proven to be effective in avoiding moisture absorption, preventing hydrolysis of the hygroscopic elastomer, and reducing or eliminating the formation of dark blue gels and holes in web. In some higher stretch ratio cases, gels rendered holes and even web break.

A multi-layer breathable barrier film <NUM> in accordance with the present disclosure may contain one or a plurality of monolithic moisture-permeable barrier layers <NUM>, each of which may be placed in any order in the inner layers of the film structure. In illustrative embodiments, the monolithic moisture-permeable barrier layer <NUM> is not placed on the outer surface of the resultant film <NUM> in order to avoid damage caused by foreign materials. In one example, when the film <NUM> contains a plurality of monolithic moisture-permeable barrier layers <NUM>, individual monolithic moisture-permeable barrier layers <NUM> are not placed adjacent to each other inside the film in order to increase efficacy. When a plurality of monolithic moisture-permeable barrier layers <NUM> is used, the individual monolithic moisture-permeable barrier layers <NUM> may differ from each other in thickness and/or type of thermoplastic polymer.

In one example, a representative structure for a multi-layer breathable barrier film <NUM> contains five layers (not shown), with one monolithic moisture-permeable barrier layer being in the core of the structure and four microporous breathable film layers being arranged around the core. In one example, the five-layer breathable barrier film has a A-C-B-C-A structure, wherein A represents a first microporous breathable film layer, C represents a second microporous breathable film layer that is different than or the same as the first microporous breathable film layer, and B represents a monolithic moisture-permeable barrier layer.

In one example, the outermost microporous breathable film layer (A and/or C) contains Dow <NUM> LLDPE or Dow PL1280 ULDPE or Dow <NUM> LLDPE, and calcium carbonate. Additional antioxidants, colorants, and/or processing aids may optionally be added. The microporous breathable film layer A may differ from the microporous breathable film layer C in the amount and/or identity of solid filler present (e.g., calcium carbonate, barium sulfate, talc, glass spheres, other inorganic particles, etc.). The inner monolithic moisture-permeable barrier layer B may contain a hygroscopic elastomer such as Dupont HYTREL PET and an adhesive such as Dupont BYNEL <NUM><NUM>%EVA or Dupont AC1820 acrylate, with additional antioxidants, colorants, and processing aids optionally being added. In one example, the inner monolithic moisture-permeable barrier layer B contains about <NUM>% adhesive and about <NUM>% by weight or more of hygroscopic elastomer. Instead of a polyester elastomer, other hygroscopic polymers, such as ε-caprolactone, polyester block amides, polyester elastomers, polyamides, and blends thereof may be utilized as the inner monolithic moisture-permeable barrier layers.

Multi-layer breathable barrier films <NUM> of a type described above are not limited to any specific kind of film structure. Other film structures may achieve the same or similar result as the three-layer film <NUM> shown in <FIG> or the five-layer structure A-C-B-C-A described above. Film structure is a function of equipment design and capability. For example, the number of layers in a film depends only on the technology available and the desired end use for the film. Representative examples of film structures that may be implemented in accordance with the present disclosure include but are not limited to the following, wherein A represents a microporous breathable film layer (e.g., <NUM> or <NUM>) and B represents an alcohol and viral monolithic moisture-permeable barrier layer (e.g., <NUM>):.

In the above-described exemplary film structures, each of the microporous breathable film layers A may include two or more microporous breathable film layers in order to better control other film properties, such as the ability to bond to nonwovens. For example, when there are two microporous breathable film layers in one A microporous breathable film layer, and when C represents the second microporous breathable film layer, some exemplary film structures are as follows:.

Additionally, die technology that allows production of multiple layers in a multiplier fashion may be used. For example, an ABA structure may be multiplied from about <NUM> to about <NUM> times. The resulting <NUM>-time multiplied ABA structure may be expressed as follows:
A-B-A-A-B-A-A-B-A-A-B-A-A-B-A-A-B-A-A-B-A-A-B-A-A-B-A-A-B-A.

Representative applications using a microporous breathable film <NUM> and/or a multi-layer breathable barrier film <NUM> include but are not limited to medical gowns, diaper back sheets, drapes, packaging, garments, articles, carpet backing, upholstery backing, bandages, protective apparel, feminine hygiene, building construction, bedding and/or the like. Films in accordance with the present disclosure may be laminated to a fabric, scrim, or other film support by thermal, ultrasonic, and/or adhesive bonding. The support may be attached to at least one face of the film and or to both faces of the film. The laminate may be made using wovens, knits, nonwovens, paper, netting, or other films. Adhesive bonding may be used to prepare such laminates. Adhesive bonding may be performed with adhesive agents such as powders, adhesive webs, liquid, hot-melt and solvent-based adhesives. Additionally, these types of support may be used with ultrasonic or thermal bonding if the polymers in the support are compatible with the film surface. Laminates of the present multilayer films and nonwoven fabrics may provide surgical barriers. In one example, the fabrics are spunbonded or spunbond-meltblown-spunbond (SMS) fabrics. In another example, the fabrics may be spunlaced, airlaid, powder-bonded, thermal-bonded, or resin-bonded. The encasing of the monolithic moisture-permeable barrier layer <NUM> protects the monolithic moisture-permeable barrier layer <NUM> from mechanical damage or thermal damage and allows for thermal and ultrasonic bonding of the multilayer film at extremely low thicknesses.

Multi-layer breathable barrier films <NUM> in accordance with the present disclosure may be used in applications in the medical field. Porous webs are used currently in the medical field for Ethylene Oxide (EtO) sterilization as the gas must be able to permeate packaging in order to sterilize the contents. These porous webs are often used as the top sheets for rigid trays and as breather films in pouches. Medical paper is commonly used for these purposes as is Tyvek (spunbond HDPE). The multi-layer breathable barrier films <NUM> in accordance with the present disclosure may be used to replace either of these products in such applications.

In one example, multi-layer breathable barrier films <NUM> in accordance with the present disclosure may be used in any application that involves a blood barrier. For example, disposable blankets, operating table covers, or surgical drapes may incorporate a multilayer breathable barrier film <NUM> in accordance with the present disclosure , as they represent blood barrier applications that might function more comfortably with a breathable substrate.

In some embodiments, as described above, the present disclosure provides microporous breathable films <NUM> (e.g., mono-layer or multi-layer) and multi-layer breathable barrier films <NUM>. In other embodiments, the present disclosure further provides personal hygiene products containing one or more microporous breathable films (e.g., mono-layer or multi-layer) in accordance with the present disclosure, and/or one or more multi-layer breathable barrier films in accordance with the present disclosure. In illustrative embodiments, a personal hygiene product in accordance with the present disclosure includes at least one inner microporous breathable film <NUM> prepared by a process as described above and at least one outer non-woven layer. The at least one inner microporous breathable film <NUM> is configured for contacting skin and/or clothing of a user of the personal hygiene product. In some embodiments, the personal hygiene product further includes at least one monolithic moisture-permeable barrier layer <NUM> disposed between the at least one inner microporous breathable film <NUM> and the at least one outer non-woven layer.

In one example, the at least one inner microporous breathable film is bonded to the at least one outer non-woven layer without an adhesive (e.g., via heat sealing, ultrasonic welding, and/or the like). In some embodiments, each of the at least one inner microporous breathable film <NUM> and the at least one outer non-woven layer comprises polypropylene and/or polyethylene. In illustrative embodiments, the inner microporous breathable film <NUM> includes calcium carbonate as the solid filler.

In illustrative embodiments, the personal hygiene product in accordance with the present disclosure is configured as an incontinence brief, a surgical gown, or a feminine hygiene product.

The following examples and representative procedures illustrate features in accordance with the present disclosure, and are provided solely by way of illustration. They are not intended to limit the scope of the appended claims or their equivalents.

For production of the example films, an extrusion cast line with up to <NUM> extruders was used. The "A" and "B" extruders are <NUM>½" in diameter, and the "C" extruder is <NUM>¾" in diameter. The extruders feed into a combining feedblock manufactured by Cloeren Corporation of Orange, TX, which can layer the A, B and C extruder outputs in a variety of configurations. From the feedblock, the molten polymer proceeds into a monolayer cast die (manufactured by Cloeren) that is about <NUM>" wide. The die has an adjustable gap. For the samples described herein, the adjustable gap was maintained between <NUM> and <NUM> mils. The molten polymer drops down to a chill roll. For the samples described herein, the chill roll had an embossed pattern FST-<NUM> which was engraved by Pamarco of Roselle, NJ as their pattern P-<NUM>. The embossed pattern P-<NUM> is a square pattern (e.g., with lines nearly aligned with the Machine Direction) with <NUM> squares per inch and a depth of about <NUM> microns. The roll itself has an <NUM>" diameter with internal water cooling. The engrave roll pattern may be replaced with other patterns that are shallow enough not to interfere with a vacuum box quench. One alternative is a <NUM> Ra pattern (<NUM> microinch average roughness) generated by a sand-blasting process on a chrome plated roll.

In this experiment, microporous breathable films were made from the formulation XC3-<NUM>-<NUM> shown in Table <NUM>.

The molten web formed by extrusion of the composition XC3-<NUM>-<NUM> shown in Table <NUM> was quenched by either a conventional embossed roll process or a chill cast vacuum box process in accordance with the present disclosure on a 250T roll (<NUM> rpm setting). The physical properties of a film made by the conventional embossed roll process and a film made by the chill cast process in accordance with the present disclosure are shown in Table <NUM>. Table <NUM> further includes physical properties for a third film made by the chill cast vacuum box process, which was down-gauged to <NUM> gsm. In Table <NUM> and in subsequent tables, Elmendorf tear results that are below the assay range of the equipment are indicated by an asterisk and should be regarded as being for reference only.

As shown by the data in Table <NUM>, a microporous breathable film in accordance with the present disclosure shows substantially improved TD tear, and puncture properties as compared to a conventional embossed roll film. For example, microporous breathable films prepared by the chill cast process show greater MD tensile strength and less MD elongation as compared to the embossed film. Moreover, surprisingly, the non-embossed microporous breathable film exhibits a reduced water vapor transmission rate (WVTR) as compared to the comparable embossed film. This observation stands in contrast to the findings reported in <CIT>, which states that the MVTR (moisture vapor transmission rate) of a non-embossed film is greater than the MVTR of a comparable embossed film that is incrementally stretched under essentially the same conditions.

The embossed process is prone to draw resonance. As a result, microporous breathable films prepared by a conventional embossing process typically include LDPE to assist in the processing. However, for microporous breathable films prepared by a chill cast vacuum box quenching process in accordance with the present teachings, the LDPE may be omitted, thereby affording stronger films having properties that were heretofore unachievable with conventional films.

Seven formulations containing a CaCO<NUM>-containing compound (CF7414 or T998K5) were used to prepare microporous breathable films in accordance with the present disclosure. In each of these seven formulations, the CaCO<NUM>-containing compound (CF7414 or T998K5) is present in <NUM>% by weight and PPA is present in <NUM>%. The remainder of the formulations is a polymer or polymer blend. The composition of the seven formulations, including the compositions of the polymer/polymer blend constituting the balance, is shown in Table <NUM> below.

The films made from formulations <NUM> and <NUM> were <NUM> gsm, whereas films made from formulations <NUM>-<NUM> and <NUM> were <NUM> gsm.

The composition of the CaCO<NUM>-containing compounds CF7414 and T998K5 shown in Table <NUM> are specified in Table <NUM> below.

The seven formulations shown in Table <NUM> were used to make a series of microporous breathable films. The films were subjected to varying amounts of pre-stretch and, in some cases to MD IMG stretching. The physical properties of the films thus prepared are summarized in Tables <NUM>, <NUM>, and <NUM> below.

Data for a series of microporous breathable films prepared by conventional methods (e.g., Windmoeller & Hoelscher blown MDO film, cast MDO films, and cast IMG films) are shown in Table <NUM> below. Data for a series of microporous breathable films prepared by a vacuum box process in accordance with the present teachings are shown in Table <NUM> below.

As shown by the data in Table <NUM>, the blown MDO film exhibits poor strain and tear properties. Moreover, the strain at peak MD corresponding to the films in Table <NUM> are substantially higher than those in Table <NUM>. In addition, the films in Table <NUM> exhibit excellent Dart Drop and slow puncture characteristics.

A series of <NUM> skinless microporous breathable films having a structure BBBBB were prepared from the formulation XC1-<NUM>-<NUM> shown in Table <NUM>. The composition of compound CF7414 is given above in Table <NUM>.

The <NUM> films were subjected to the following different processing conditions: basis weights (<NUM> gsm vs. <NUM> gsm), pre-stretch (<NUM>%/<NUM>% vs. <NUM>%/<NUM>%), depth of engagement (<NUM> vs. <NUM>), and post-stretch (<NUM>% vs. <NUM>%). The physical properties of the resultant films are summarized in Table <NUM>-<NUM>.

In Tables <NUM>-<NUM>, the legend W/X/Y/Z is a shorthand nomenclature signifying basis weight (gsm)/pre-stretch/depth of engagement of IMG rolls/post-stretch. For example, the designation <NUM>/<NUM>/<NUM>/<NUM> represents a basis weight of <NUM> gsm, <NUM>%/<NUM>% pre-stretch, a depth of engagement of <NUM>, and <NUM>% post-stretch.

A series of <NUM> skinned microporous breathable films having a structure CBBBC were prepared from the formulation XC1-<NUM>-<NUM> shown in Table <NUM>. The composition of compound CF7414 is given above in Table <NUM>.

In Tables <NUM>-<NUM>, the legend W/X/Y/Z is a shorthand nomenclature signifying basis weight (gsm)/pre-stretch/depth of engagement of IMG rolls/post-stretch. For example, the designation <NUM>/<NUM>/<NUM>/<NUM> represents a basis weight of <NUM> gsm, <NUM>%/<NUM>% pre-stretch, a depth of engagement of <NUM>, and <NUM> post-stretch.

Two microporous breathable films A3 and B3 having a structure CBBBC were prepared from the formulation XC3-<NUM>-<NUM> shown in Table <NUM>. The physical properties of the resultant films are shown in Table <NUM>.

In Table <NUM>, the legend X/Y/Z is a shorthand nomenclature signifying pre-stretch/depth of engagement of IMG rolls/post-stretch. For example, the designation <NUM>/<NUM>/<NUM> corresponding to film A2 represents a <NUM>%/<NUM>% pre-stretch, a depth of engagement of <NUM>, and <NUM>% post-stretch. Surprisingly and unexpectedly, the films A2 and B2 exhibit high Dart Impact Strength (e.g., greater than <NUM> grams) in spite of exceptionally low basis weights (e.g., less than <NUM> gsm).

The overall thickness of the microporous breathable film may be varied depending on the particular end use for which the film is manufactured. In illustrative embodiments, films in accordance with the present disclosure have a thickness that is less than typical thicknesses for microporous breathable films. As described above, the beneficial properties of microporous breathable films prepared in accordance with the present disclosure by using a vacuum box, air knife, and/or air blanket to cast a molten web against a chill roll may include one or more of reduced basis weight, increased Dart Impact Strength, increased strain at peak machine direction, and/or the like, and may allow the films to be used at a decreased gauge or thickness as compared to conventional microporous breathable films. However, basis weights and thicknesses may be easily adjusted to fit a desired end use.

Polypropylene microporous breathable films A4 through D4 having a structure A/B/A (<NUM>/<NUM>/<NUM> layering), and polypropylene microporous breathable films E4 through H4 having a structure A/B/A (<NUM>/<NUM>/<NUM> layering), were prepared from the formulation XC3-<NUM>-<NUM> shown in Table <NUM>. The composition of compounds T1000J2 and CF7414* shown in Table <NUM> is specified in Table <NUM> below.

The physical properties of the resultant polypropylene films are shown in Table <NUM> below. The films A4, B4, E4, and F4 were not subjected to any post-stretching, whereas the films C4, D4, G4, and H4 received <NUM>% post-stretch. The films A4, B4, C4, and D4 have a <NUM>/<NUM>/<NUM> A/B/A layering, whereas the films E4, F4, G4, and H4 have a <NUM>/<NUM>/<NUM> A/B/A layering.

As shown in Table <NUM>, the <NUM>-gsm film D4 exhibits an impressive force at peak MD of <NUM>/in and an impressive force at <NUM>% strain MD of <NUM>/in. The force at <NUM>% strain MD measurement reflects the degree to which a film may be stretched when pulled (e.g., by a consumer). In addition, as shown in Table <NUM>, the <NUM>-gsm film D4 also exhibits a high TEA MD of <NUM> Ft·Lb/in<NUM>, which is a measure of the toughness of the film (wherein higher numbers corresponding to increased robustness).

The <NUM>-gsm film D4 shown in Table <NUM> was ultrasonically bonded to a <NUM>-gsm spunbond polypropylene homopolymer material by Herrmann Ultrasonics. The film D4 was bonded to the polypropylene homopolymer using microgap control, a <NUM>-kHz ultrasonic horn, and a bond roll having a discrete bond pattern. The ultrasonically bonded material thus formed exhibited good bonding characteristics and represents an example of how a film in accordance with the present disclosure may be bonded to a nonwoven material without the use of an adhesive. As such, a film in accordance with the present disclosure (e.g., a polypropylene film including but not limited to the film D4 shown in Table <NUM>) may be desirable for use in forming personal hygiene products (e.g., including but not limited to incontinence briefs, adult underpads for incontinence, surgical gowns, drapes, feminine hygiene products), and Protective Apparel such as garments, aprons, gloves or the like).

Polypropylene microporous breathable films I4 through L4 having a structure A/B/A (<NUM>/<NUM>/<NUM> layering) were prepared from the formulation XC3-<NUM>-<NUM> shown in Table <NUM>. The composition of compound CF7414* shown in Table <NUM> is specified above in Table <NUM>.

The physical properties of the resultant polyethylene with blended polypropylene films are shown in Table <NUM> below. The films I4 and K4 were not subjected to any post-stretching, whereas the films J4 and L4 received <NUM>% post-stretch. The films I4, J4, K4, and L4 have a <NUM>/<NUM>/<NUM> A/B/A layering.

As shown in Table <NUM>, the <NUM>-gsm film L4 exhibits an impressive force at peak MD of <NUM>,<NUM>/in and an impressive force at <NUM>% strain MD of <NUM>/in. In addition, as shown in Table <NUM>, the <NUM>-gsm film D4 also exhibits a high TEA MD of <NUM>,<NUM> Ft·Lb/in<NUM>, which is a measure of the toughness of the film (with higher numbers corresponding to increased robustness).

Surprisingly and unexpectedly, the polyethylene-blended polypropylene film L4 manufactured from the formulation XC3-<NUM>-<NUM> is softer to the touch than the pure polypropylene film D4 manufactured from the formulation XC3-<NUM>-<NUM>. Moreover, surprisingly and unexpectedly, a polyethylene-blended polypropylene film (e.g., the film L4 shown in Table <NUM>) may exhibit better properties that a pure polypropylene film (e.g., the film D4 shown in Table <NUM>).

The <NUM>-gsm film L4 shown in Table <NUM> was ultrasonically bonded to a <NUM>-gsm spunbond polypropylene homopolymer material by Herrmann Ultrasonics. The film L4 was bonded to the polypropylene homopolymer using microgap control, a <NUM>-kHz ultrasonic horn with a width of <NUM>, and a bond roll having a discrete bond pattern. The ultrasonically bonded material thus formed exhibited good bonding characteristics and represents a further example of how a film in accordance with the present disclosure may be bonded to a nonwoven material without the use of an adhesive. As such, a film in accordance with the present disclosure (e.g., a polyethylene-blended polypropylene film including but not limited to the film L4 shown in Table <NUM>) may be desirable for use in forming personal hygiene products (e.g., including but not limited to incontinence briefs, surgical gowns, feminine hygiene products, and/or the like).

Pressure penetration of simulated blood was tested using the "Pressure Penetration Through a Fabric (PPT)" test. The PPT test is used to determine whether or not, and to what degree, simulated blood penetrates through a fabric or film under pressure for a specified time.

A sample is placed on a blotter paper on a flat surface and challenged by a <NUM>% IPA/water solution containing Astrazon Red Violet dye for <NUM> minutes while under a <NUM> psi load. The number of red spots showing on the blotter paper are determined and recorded. The test solution contains <NUM>% IPA/<NUM>% DI water with <NUM>% (<NUM> gram per liter or <NUM> gm per <NUM>) of Astrazon Red Violet 3RN liquid dye added for visibility. This method is performed in a lab at standard atmosphere for testing textiles: <NUM> °F (<NUM>), <NUM>% RH.

In the PPT test, the pre-marked blotter paper is laid on a hard, flat surface near a sink. A <NUM>"x3"' test specimen is placed, face side up, on the blotter on each of the <NUM> or <NUM> pre-marked lane squares. A <NUM>"x2" piece of absorbent spun-bond non-woven fabric is placed in the center of each specimen. A pipette is filled with the test solution and the <NUM>"x2" nonwoven is saturated with it. A cylindrical, <NUM>" diameter; <NUM> lb (<NUM> psi) weight is placed on top of the saturated specimen and a timer is started. After <NUM> minutes, the weights are removed and all except the blotter paper are discarded. The blotter paper is examined, and all red spots are counted. The number of red spots is recorded. A size limit may be specified for red spots to be counted. If one large red blotch is present, the result may be recorded as "<NUM>.

Polypropylene microporous breathable film samples A5-C5 having a structure A/B/A (<NUM>/<NUM>/<NUM> layering) were prepared from the formulation XC3-<NUM>-<NUM> shown in Table <NUM> above. Polypropylene microporous breathable film samples D5-F5 having a structure A/B/A (<NUM>/<NUM>/<NUM> layering) were prepared from the formulation XC3-<NUM>-<NUM> shown in Table <NUM> above. Polypropylene microporous cored film samples G5 and H5 having a structure A/B/A (<NUM>/<NUM>/<NUM> layering) were prepared from the formulation XC3-<NUM>-<NUM> shown in Table <NUM> below. The microporous cored films have a microporous core layer, but are not breathable as they have solid skin layers surrounding the breathable core layer. The composition of compound CF7414* shown in Table <NUM> is specified above in Table <NUM>.

The PPT Test Data for the polyethylene-blended polypropylene microporous breathable films A5-H5 are summarized in Table <NUM> below.

Additional PPT testing on films A5-H5 was performed using a <NUM>-inch square film. The nonwoven side of the film was placed on the blotter paper, and <NUM><NUM> of dye was added for a duration of <NUM> seconds. The results of this additional testing are shown in Table <NUM> below.

For comparative purposes, polypropylene-containing non-breathable film samples A6-F6 having a structure A/B/A (<NUM>/<NUM>/<NUM> layering) were prepared from the formulation XP-1943SX shown in Table <NUM> below.

The PPT Test Data for the comparative polyethylene-blended polypropylene non-breathable films A6-F6 are summarized in Table <NUM> below.

As shown by the data in Tables <NUM> and <NUM>, polyethylene cored films with polypropylene containing skins in accordance with the present disclosure were able to provide a destruct bond at a low bonding force (e.g., <NUM> Newtons). By comparison, as shown by the data in Table <NUM>, polyethylene-blended with polypropylene non-cavitated films were unable to provide a destruct bond at such a comparably low bonding force despite the high level of polypropylene in the formula. Moreover, while the PPT test results for the microporous breathable films A5-G5 are comparable to the PPT test results for the non-breathable films A6-E6, it is surprising and unexpected that a microporous breathable film in accordance with the present disclosure is able to provide barrier performance comparable to that of a non-breathable film while further providing breathability.

Four hybrid microporous-monolithic multi-layer breathable barrier films A7-D7 having polyethylene-containing microporous breathable skins, a thermoplastic copolyester elastomer core, and an A/B/C/B/A structure were prepared from the formulation XC5-<NUM>-<NUM> shown in Table <NUM> below.

Four hybrid microporous-monolithic multi-layer breathable barrier films E7-H7 having polypropylene-containing microporous breathable skins, a thermoplastic copolyester elastomer core, and an A/B/C/B/A structure were prepared from the formulation XC5-<NUM>-<NUM> shown in Table <NUM> below.

Four hybrid microporous-monolithic multi-layer breathable barrier films I7-L7 having polyethylene-containing microporous breathable skins, a thermoplastic polyester elastomer core, and an A/B/C/B/A structure were prepared from the formulation XC5-<NUM>-<NUM> shown in Table <NUM> below.

Four hybrid microporous-monolithic multi-layer breathable barrier films M7-P7 having polypropylene-containing microporous breathable skins, a thermoplastic polyester elastomer core, and an A/B/C/B/A structure were prepared from the formulation XC5-<NUM>-<NUM> shown in Table <NUM> below.

The composition of the CaCO<NUM>-containing compound CF7414* shown in Tables <NUM>-<NUM>, and the composition of the CaCO<NUM>-containing compound T1000J2 shown in Tables <NUM> and <NUM>, are specified in Table <NUM> above.

The physical properties of the resultant films A7-H7 are shown in Table <NUM> below, and the physical properties of the resultant films I7-P7 are shown in Table <NUM> below. Each of films A7-P7 received <NUM>% post-stretch. The alcohol penetration test data shown in Tables <NUM> and <NUM> represents the degree to which the monolithic layer remains intact, with values between <NUM> and <NUM> being indicative of particularly good performance. As shown in Tables <NUM> and <NUM>, many of the films exhibit high Dart Impact Strength (e.g., greater than <NUM> grams) in spite of low basis weights (e.g., <NUM> gsm).

As shown by the data in Tables <NUM> and <NUM>, multi-layer breathable barrier films in accordance with the present disclosure are able to achieve low alcohol penetration (e.g., <NUM>% to <NUM>%) at low basis weights (e.g., <NUM> gsm).

A tie resin-containing multi-layer breathable barrier film A8 having polypropylene microporous breathable skins, a thermoplastic copolyester elastomer core, and an A/B/C/B/A structure was prepared from the formulation XC5-<NUM>-<NUM>. 6A shown in Table <NUM> below. The tie resin (BYNEL 22E757) is a modified ethylene acrylate.

A tie resin-free multi-layer breathable barrier film B8 having polypropylene microporous breathable skins, a thermoplastic copolyester elastomer core, and an A/B/C/B/A structure was prepared from the formulation XC5-<NUM>-<NUM> shown in Table <NUM> below.

The composition of the CaCO<NUM>-containing compound T1001R1 shown in Tables <NUM> and <NUM> is specified in Table <NUM> below.

The physical properties of the resultant films A8 and B8 are shown in Table <NUM> below. Each of films A8 and B8 received <NUM>% post-stretch and was subjected to CD IMG stretching at a depth of <NUM> inches.

Surprisingly and unexpectedly, it was possible to successfully produce rolls of film that were subsequently hot melt-adhesively-laminated to a nonwoven layer with both the tie resin-containing formulation XC5-<NUM>-<NUM>. 6A and the tie resin-free formulation XC5-<NUM>-<NUM>. Heretofore, it had been believed that a tie resin adhesive would be required to keep the layers from separating during manufacture or handling. However, a manufacturing process in accordance with the present disclosure utilizing CD IMG activation allows the layers to remain together, thereby dispensing with the requirement of a tie resin.

Claim 1:
A process for making a microporous breathable film comprising the steps of
extruding a composition comprising a polyolefin and an inorganic filler to form a molten web,
casting the molten web against a surface of a chill roll using an air knife, air blanket, a vacuum box, or a combination thereof, and without use of a nip, to form a quenched film, and
stretching the quenched film to form the microporous breathable film, wherein the stretching comprises cross-directional intermeshing gear stretching;
wherein the microporous breathable film made by the process has a basis weight of less than <NUM> gsm and a strain at peak machine direction of at least <NUM>% according to ASTM D882.