WO2012027884A1

WO2012027884A1 - Ostomy pouch and film for making same

Info

Publication number: WO2012027884A1
Application number: PCT/CN2010/076476
Authority: WO
Inventors: Parimal M. Vadhar; Jian Liang; Xiaojun Li
Original assignee: Cryovac, Inc.
Priority date: 2010-08-30
Filing date: 2010-08-30
Publication date: 2012-03-08
Also published as: CN103079502A; CN103079502B

Abstract

Monolayer and multilayer, flexible films are provided for containing medical and bodily fluids that can be used in the production of medical packaging, in particular, an ostomy pouch. The films have a high content, i.e., greater than about 40 wt %, of a vinyl acetate copolymer, an acrylate copolymer, and combinations thereof. A pouch, for example, an ostomy pouch, constructed of the films of the invention is provided. A multifilm pouch, for example, an ostomy pouch, having an inner film, a front film panel, and a back film panel constructed of these high content vinyl acetate copolymer and acrylate copolymer films is also provided.

Description

OSTOMY POUCH AND FILM FOR MAKING SAME

FIELD OF INVENTION

Embodiments of the present invention relate generally to films for containing medical and bodily fluids and particularly to flexible films that can be used in the production of medical packaging, in particular, an ostomy pouch.

BACKGROUND OF THE INVENTION

Multilayer films having gas and odor barrier properties are well known and widely used in food and medical packaging applications. Generally, it is desirable for such films to have good impact resistance, flexibility, barrier properties, and desirable optical properties.

In the case of medical packaging, such as, for example, ostomy pouches, the pouch may include one or more fitments, such as a tube or mounting plate, also commonly called a wafer or baseplate, that provide a means for accessing the interior of the pouch. Fitments provide a means for establishing fluid communication between the interior of the pouch and the outside environment.

Generally, a fitment is attached to the film by welding the fitment directly to an inner surface of the film during the process of making the pouch. The fitments are typically welded through heat sealing, such as impulse sealing, or using radio frequency (RF).

Where the films are to be used in medical applications, such as ostomy applications, they must also possess a unique combination of odor and moisture barrier properties as well as low noise, softness, heat or radio-frequency sealability, skin compatibility, and comfort. Such films have been provided in the past through the use of multi-ply film laminates where at least one of the plies is oxygen and moisture vapor impermeable.

In addition to barrier properties, it is often desirable that polymeric films for use in ostomy applications to not emit noise during use, such as when the film is crumpled or bent, so that the presence of the ostomy pouch is concealed from others. In particular, it has been found that the use of ostomy pouches makes the patient feel uneasy about such containers emitting, especially as the patient moves around, noise of a low but still audible intensity level. Most polymeric films, especially multilayer polymer films comprised of individual polymeric film layers having different rigidities (e.g., modulus), emit noise when crumpled. Such noise may alert others to the presence of the ostomy pouch, which can result in embarrassment to the wearer. Hence, the primary requirements for materials for the construction of ostomy pouches are flexibility, softness, barrier to odor, light weight and a comfortable feel to the skin. These requirements are usually met in existing laminates by combining a barrier film, which may be a monolayer or multilayer construction, and which is typically in the range of about 50 to about 200 micrometres or about 2 to 7.5 mils thick, with a skin contact substrate material, either nonwoven or perforated which is secured to the barrier film through a peripheral pouch seal.

There remains a need for films that are flexible having sound dampening properties that can be used in medical devices for containing medical fluids.

BRIEF SUMMARY OF THE INVENTION

Embodiments of the present invention are directed to an ostomy pouches and a film for making the same that helps meet many of the aforementioned needs. In one particular embodiment, the present invention is directed to a film having liquid and odor barrier properties, flexibility, low noise, and improved softness. As a result, films in accordance with the invention may be particularly useful in the construction of ostomy pouches.

The inventors of the present invention have discovered that films having at least one exterior layer comprising a relatively high content of vinyl acetate copolymer have a low modulus of elasticity and improved softness. The low modulus of elasticity helps reduce the amount of noise generated when the film is crumpled or flexed. Additionally, improved softness in the film helps provide greater comfort when the film is in contact with human skin.

The film may have one or more layers where at least one of the layers comprises at least about 40 wt% of an ethylene vinyl acetate copolymer, an acrylate copolymer, or any combination thereof and at least one or more of a linear low density polyethylene (LLDPE), a low density polyethylene LDPE, and a very low density polyethylene VLDPE.

In certain embodiments of the invention, any of the one or more layers of the film has at least about 40 wt % of an ethylene vinyl acetate (EVA) copolymer. In certain

embodiments of the invention, the EVA copolymer comprises from about 18 to about 27 wt % of vinyl acetate.

In one embodiment, the film includes at least one layer comprising a blend of an ethylene vinyl acetate, at least one of LLDPE, LDPE, or VLDPE, and from about 7 to about 40 wt % of an ethylene acrylic acid (EAA) copolymer. In still other embodiments of the invention, such layers may additionally comprise an ethylene butyl acrylate (EBA) copolymer. Any of the one or more layers of the film may additionally comprise an antiblocking agent.

According to certain embodiments of the invention, it may be desirable that the film have a modulus of elasticity that is less than about 15,000 psi, and in particular, less than about 14,400 psi. In one embodiment, the film has a modulus of elasticity that is less than about 12,000 psi. In certain embodiments of the invention directed to a multilayer pouch, the modulus of elasticity of the inner film is less than about 14,400 psi; the modulus of elasticity of the film used to construct a front panel is less than about 12,000 psi, alternatively, less than about 10,000 psi; and the modulus of elasticity of the film used to construct a back panel is less than about 12,000 psi, alternatively, less than about 10,000 psi. Without intending to be bound by theory, it is believed that a lower modulus of elasticity helps to improve flexibility and reduce the amount of noise generated by the film when crumpled or flexed.

In one embodiment, the present invention is directed to pouch formed from two or more films that are joined together to define a pouch having an interior cavity. This pouch, also referred to as a multifilm pouch, typically comprises an inner film interconnected such that it defines a cavity that is configured to contain a fluid, such as a medical fluid or a bodily fluid. The multifilm pouch additionally comprises a front panel and a back panel arranged in opposing face-to-face relation, a top end, a bottom end, and a pair of opposing side edges extending longitudinally between the top end and the bottom end. The front panel and the back panel are fixedly joined to the inner film and adheredly joined to each other along their adjacent peripheral edges to form a seam at the opposing side edges.

The ostomy pouch may include small tubings or fitments attached to the top end and the bottom end of the pouch for fluid entry and fluid exit. In certain embodiments of the invention, the inner film may be interconnected to define a fluid entry and/or a fluid exit.

Pursuant to certain embodiments of the invention, the inner film has one or more layers comprising at least about 40 wt% of a vinyl acetate copolymer, an acrylate copolymer, and any combination thereof and any one or more of a LLDPE, a LDPE, and a VLDPE. In yet other embodiments of the invention, the front panel comprises a film having one or more layers comprising at least about 40 wt% of a vinyl acetate copolymer, an acrylate copolymer, and any combination thereof and any one or more of a LLDPE, a LDPE, and a VLDPE. Any of the one or more layers of the film making up the front panel may comprise an EBA copolymer.

In yet other embodiments of the invention, the back panel comprises another film having one or more layers comprising at least about 40 wt% of a vinyl acetate copolymer, an acrylate copolymer, and any combination thereof and any one or more of a LLDPE, a LDPE, and a VLDPE. In other embodiments of the invention, any of the one or more layers of the film making up the back panel additionally comprises a pigment such as Ti0₂.

In an embodiment of the invention, the front panel and the back panel are

unconnected at the top end to allow for filling of the multifilm pouch. In an embodiment of the invention, the front panel and the back panel include inner surfaces that are heat sealed to each other along the bottom end of the pouch.

In an embodiment of the invention, the inner film is a single sheet having two longitudinal side edges. Further pursuant to this embodiment, the sheet material is folded to form opposing side edges of an inner portion of the multifilm pouch and the opposing side edges are sealed to each other to form a vertical seam that extends longitudinally along a length of the inner portion to define the cavity.

In another aspect, a monolayer or multilayer flexible film is provided.

In one embodiment, the film comprises at least one layer having at least about 40 wt% of a vinyl acetate copolymer, an acrylate copolymer, and any combination thereof. The film additionally comprises any one or more of a LLDPE, a LDPE, and a VLDPE. The film desirably has a modulus of less than about 14,400 psi in order to provide flexibility and approach the necessary sound dampening properties.

Specifically, any one or more layers of the film may comprise from about 17 to about 50 wt % of an EVA copolymer, from about 7 to about 40 wt % of an EAA copolymer, an EBA copolymer, and/or an antiblocking agent. In certain embodiments of the invention, the EVA copolymer has from about 18 to about 27 wt % of vinyl acetate. In certain

embodiments of the invention, any one or more layers of the film comprises at least about 20 wt % of any one or more of a LLDPE, a LDPE, and a VLDPE.

In an embodiment of the invention, the film is a multilayer film comprising a first exterior layer having at least about 40 wt% of a vinyl acetate copolymer, an acrylate copolymer, and any combination thereof and any one or more of a LLDPE, a LDPE, and a VLDPE. In certain embodiments of the invention, the first exterior layer of the film comprises any one or more of from about 20 to about 50 wt % of an EVA copolymer, from about 7 to about 36 wt % of an EAA copolymer, an EBA copolymer, and/or an antiblocking agent. In certain embodiments of the invention, the EVA copolymer has from about 18 to about 27 wt % of vinyl acetate.

The multilayer film additionally comprises a second exterior layer, for example, the second layer comprising at least about 40 wt% of a vinyl acetate copolymer, an acrylate copolymer, and any combination thereof and any one or more of a LLDPE, a LDPE, and a VLDPE. In certain embodiments of the invention, the second exterior layer of the film comprises any one or more of from about 20 to about 40 wt % of an EVA copolymer, from about 7 to about 20 wt % of an EAA copolymer, an EBA copolymer, and/or an antiblocking agent. In certain embodiments of the invention, the EVA copolymer has from about 18 to about 27 wt % of vinyl acetate.

In certain embodiments of the invention, the multilayer film may have at least one interior layer comprising at least about 40 wt% of a vinyl acetate copolymer, an acrylate copolymer, and any combination thereof and any one or more of a LLDPE, a LDPE, and a VLDPE. In certain embodiments of the invention, the at least one interior layer of the film comprises any one or more of at least about 40 wt % of an EVA copolymer, from about 7 to about 40 wt % of an EAA copolymer, an EBA copolymer, and/or an antiblocking agent. In certain embodiments of the invention, the EVA copolymer has from about 18 to about 27 wt % of vinyl acetate.

In certain embodiments, the multilayer film of the invention has a modulus of less than about 14,400 psi in order to provide flexibility and to provide sound dampening properties.

Other aspects and embodiments will become apparent upon review of the following description taken in conjunction the accompanying drawings. The invention, though, is pointed out with particularity by the appended claims.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:

FIG. 1 is a front elevation view of an ostomy pouch in accordance with an

embodiment of the present invention;

FIG. 2 illustrates a cross-section of a top view of an ostomy pouch taken along the II- II line of FIG. 1 in accordance with an embodiment of the present invention;

FIG. 3 illustrates a cross-section of a side view of an ostomy pouch taken along the III-III line in accordance with an embodiment of the present invention;

FIG. 4 illustrates a cross-section of a side view of an ostomy pouch according to FIG. 3 additionally comprising a nonwoven fabric adherently disposed across the back panel and fitments in accordance with an embodiment of the present invention; and FIG. 5 is a schematic cross-section of a five-layer film in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. While certain embodiments of the invention may be described, this invention may, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The embodiments of the invention are not to be interpreted in any way as limiting the various inventions described herein. Like numbers refer to like elements throughout.

Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. All terms, including technical and scientific terms, as used herein, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs unless a term has been otherwise defined. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning as commonly understood by a person having ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure. Such commonly used terms will not be interpreted in an idealized or overly formal sense unless the disclosure herein expressly so defines otherwise.

Unless otherwise expressly indicated to the contrary, any test standards referenced herein, for example, any ASTM test standard, refer to the most recent standard adopted prior to the time this application is filed.

Exemplary compositions of the invention are described in the examples presented herein. As a person having ordinary skill in the art to which this invention belongs would appreciate, variations or modifications from these exemplary compositions, as detailed in the specification and as further set forth in the claims that follow, are intended to be included within the scope of the present invention.

As used herein, "wt %" or "weight percent" or "% by weight" or "percent by weight" and any variations thereof, unless specifically stated to the contrary, means a weight percentage of the component based on the total weight of the composition or article in which the component is included.

With reference to FIGS. 1, 2, and 3, a front elevation view of an ostomy pouch, a cross-section of an ostomy pouch in accordance with at least one embodiment of the invention is illustrated and broadly designated by reference number 10. In the illustrated embodiment, a film will be constructed to specifically serve as a front panel 12, a film will be constructed to specifically serve as a film backing or a back panel 14, and a film will be constructed to specifically serve as an inner film 16, which is interconnected to define a cavity 18 for the containment of a fluid, for example, such as a medical fluid or a bodily fluid in the case of the ostomy pouch 10. The front panel 12 and a back panel 14 are arranged in opposing face-to-face relation. The term "pouch" as used herein also includes bags, satchels, and the like.

At least one of the front panel, back panel, or inner film comprises a film having at least one exterior layer comprising a relatively high content of vinyl acetate copolymer. For example, the front panel, back panel, or inner film may comprise a film may have one or more layers where at least one of the layers comprises at least about 40 wt% of a vinyl acetate copolymer, an acrylate copolymer, or any combination thereof and at least one or more of a LLDPE, a LDPE, and a VLDPE.

In one embodiment, the present invention provides either a monolayer or a multilayer film and certain articles of manufacture produced from the monolayer and/or the multilayer films of the invention. In certain embodiments of the invention, a multilayer film has a first exterior layer comprising a polymer blend, a second exterior that may be the same or different from the first exterior layer, and at least one inner layer disposed between the exterior layers.

Desirably, films in accordance with the invention provide a Young's modulus or modulus of elasticity as measured in accordance with ASTM D882 that is low enough to impart a desired flexibility to the film. In certain embodiments, in order to provide flexibility and help provide the desired sound dampening properties required for the film, the modulus of the film is at most about 13,700 psi, at most about 12,800 psi, at most about 12,000 psi, at most about 11,000 psi, and at most about 10,200 psi as measured in the machine direction. In certain embodiments, the modulus of the film is at most about 14,400 psi, at most about 13,700 psi, at most about 12,700 psi, at most about 11,200 psi, and at most about 9,700 psi as measured in the transverse direction. In certain exemplary embodiments of the invention, a monolayer film or a multilayer film has a modulus of about 14,400 psi or less. Young's modulus, also referred to as the modulus of elasticity, may be measured in accordance with ASTM procedure D882. Unless indicated to the contrary, all references to modulus herein refer to Young's modulus.

Referring back to FIGS. 1, 2, and 3, the ostomy pouch comprises a top end 24 and a bottom end 26, whereby either or both of the top end 24 and the bottom end 26 may comprise a fitment as illustrated in FIG. 4. For example, according to FIG. 4 the ostomy pouch may include small tubings or fitments 28, 30 attached to the top end 24 and bottom end 26 of the pouch for fluid entry 32 and fluid exit 34. In certain embodiments of the invention, the inner film 16 may be interconnected to define any of the fitments 28, 30 for fluid entry 32 and/or a fluid exit 34.

In an embodiment of the invention, the ostomy pouch 10 may be configured to be worn by a patient. In certain embodiments of the invention, the ostomy pouch 10 may be configured to be attached to a patient's bedside or even a stand using for example the handle 36 illustrated in the embodiment represented by FIG. 1. The optional handle 36 may be attached to a stand or, for example, a loop or similar device attached to a belt or harness to be worn by a patient. In other embodiments of the invention, depending, for example upon the intended use of the pouch, the pouch need not be worn by a patient and need not necessarily be configured to attach to a patient's bedside or even a stand.

Generally, the front panel 12 and the back panel 14 are fixedly joined to the inner film 16 and are adheredly joined to each other along their adjacent peripheral edges to form a seam at the opposing side edges 20, for example. However, in certain embodiments of the invention, the surface area about which the back panel 14 is disposed may be such that any portion of the back area of the ostomy pouch 10 that comes in contact with the body of the patient during normal use of the ostomy pouch 10 will be a point of contact with the back panel 14. In an embodiment of the invention, the material of the back panel 14 is defined such that it is adherent with a nonwoven fabric 22, for example, a non-woven polyester fabric, as illustrated in FIG. 4. The nonwoven layer attached to the back panel 14 is intended to provide comfort to and is compatible with the skin of the patient.

In an embodiment of the invention, the front panel 12 and the back panel 14 are unconnected along the top end 24 to allow for filling of the multifilm pouch. In other embodiments of the invention, the front panel 12 and the back panel 14 include inner surfaces that are heat sealed to each other along the bottom end 26 of the multifilm pouch.

In an embodiment of the invention, the inner film 16 may not extend the entire longitudinal length of the pouch 10 as measured from the top end 24 to the bottom end 26, for example is illustrated in FIGS. 3 and 4. In certain embodiments of the invention, the inner film extends about 1/5, about 1/4, about 1/3, about 1/2, about 2/3, and about 3/4 of the longitudinal length as measured from the top end 24 to the bottom end 26 of the pouch. In certain embodiments of the invention, the inner film 16 extends substantially the full length of the distance as measured from the top end 24 to the bottom end 26 of the pouch. Pursuant to the embodiment whereby the inner film 16 does not extend substantially the full length of the distance as measured from the top end 24 to the bottom end 26 of the pouch, the inner film may be positioned any where within the body of the pouch as defined by the front panel 12 and the back panel 14. In the exemplary embodiments represented by FIGS. 2 and 3, the inner film 16 is positioned within the body of the pouch as defined by the front panel 12 and the back panel 14 such that the inner film 16 is substantially aligned with the top end 24 and continues to extend throughout the body of the pouch as defined by the front panel 12 and the back panel 14 as further provided herein.

In certain embodiments of the invention, the inner film 16 is a single sheet having two longitudinal side edges, wherein the sheet material is folded to form opposing side edges of an inner portion of the multifilm pouch, and the opposing side edges are sealed to each other to form a vertical seam, such as a fin seal, that extends longitudinally along a length of the inner portion to define the cavity 18.

Pursuant to the embodiment for the three-film pouch as illustrated in FIGS. 1 - 4, generally, the front panel 12 and the inner film 16 may be clear to allow viewing of the fluid contained within the pouch. For example, in certain applications, the fluid may be of a particular color or have sediment, which may be informative to the person viewing the contents. Additionally, the amount of fluid contained within the pouch may also be readily viewable if the front panel 12 and inner film 16 are clear. In certain embodiments of the invention, the film of the front panel 12 may be defined such that it is amenable to being surface printed.

In certain embodiments of the invention, the front panel 12 is clear with a total transmission of about 84 % and a haze of about 45 %. Pursuant to this embodiment, the front panel 12 has the following additional properties: a thickness in a range of from about 5.3 mils to about 6.5 mils, a width of from about 10.1 to about 10.3 inches, and a length running from the top end 24 to the bottom end 26 of from about 19.7 to about 20.1 inches; a tensile at break in the machine direction of about 2,610 psi and a tensile at break in the transverse direction of about 1,450 psi; an elongation at break in the machine direction of about 700 % and elongation at break in the transverse direction of about 580 %; a moisture vapor transmission rate (MVTR) of about 14 g/m²-24 h and an oxygen transmission rate (OTR) of about 2,400 cc/m²-24 h; and an ammonia permeability of about 25,000 cm³/m²-24 h. A front panel 12 constructed to these specifications with the films as further disclosed herein is expected to have a shelf life of at least one year when stored at 77F and about 50 to about 60% relative humidity. Of course, the front panel 12 may have other varying ranges for the properties as further disclosed herein.

In certain embodiments of the invention, as further disclosed herein, the back panel 14 may be clear or a pigment may be included in the back panel, or rather a pigment may be included in any layer of the film used for the back panel 14. For example, a white pigment or a pigment imparting another color may add the background needed in order to gain a better perspective when viewing the fluid through the front panel 12 and inner film 16.

Additionally, a pigmented back panel will allow, in certain embodiments, the user to be informed of which side of the pouch is the backside and which side of the pouch is intended to be the front side. In particular, this may be important in those embodiments when a nonwoven has not additionally be affixed the back panel 14.

In certain embodiments of the invention, the back panel 14 is not clear but white with a total transmission of about 15 %. Pursuant to this embodiment, the back panel 14 has the following additional properties: a thickness in a range of from about 5.3 mils to about 6.5 mils, a width of from about 12.4 to about 12.6 inches, and a length running from the top end 24 to the bottom end 26 of from about 19.7 to about 20.1 inches; a tensile at break in the machine direction of about 2,030 psi and a tensile at break in the transverse direction of about 1,450 psi; an elongation at break in the machine direction of about 600 % and elongation at break in the transverse direction of about 500 %; a moisture vapor transmission rate (MVTR) of about 10 g/m²-24 h and an oxygen transmission rate (OTR) of about 1,700 cc/m²-24 h; and an ammonia permeability of about 48,000 cm³/m²-24 h. A back panel 14 constructed to these specifications with the films as further disclosed herein is expected to have a shelf life of at least one year when stored at 77F and about 50 to about 60% relative humidity. Of course, the back panel 14 may have other varying ranges for the properties as further disclosed herein.

According to an embodiment of the invention, the materials used in the construction of the pouch meet FDA requirements.

Pursuant to the embodiments directed to a multilayer pouch, the films making up the outside panels, such as the front panel and the back panel in the three-film pouch may be constructed to have a lower modulus than the inner film. For example, the films making up the outside panels may have a modulus of at most about 12,700 psi, at most about 12,000 psi, at most about 11,200 psi, at most about 10,000 psi, and at most about 9,700 psi as measured in the transverse direction while the modulus of the inner film is at most about 14,400 psi, at most about 13,700 psi, at most about 12,700 psi, at most about 11,200 psi, and at most about 9,700 psi as measured in the transverse direction.

In another embodiment, a pouch, according to the present invention, which may be an ostomy pouch, may have a single-film. The film may have one or more layers where any of the one or more layers comprises at least about 40 wt% of a vinyl acetate copolymer, an acrylate copolymer, and any combination thereof and any one or more of a LLDPE, a LDPE, and a VLDPE.

In an embodiment of the invention, the film defines a pouch having two longitudinal side edges and the film is folded to form opposing side edges of the pouch. The opposing side edges are sealed to each other to form a vertical seam that extends longitudinally along a length of the pouch to define the cavity.

In one embodiment of the invention, any of the one or more layers of the film has an

EVA copolymer in concentrations as provided for the films further defined herein. In an embodiment of the invention, the EVA copolymer comprises from about 5 to about 50 wt %, from about 9 to about 40 wt %, and from about 15 to about 30 wt % of vinyl acetate. In certain embodiments of the invention, the EVA copolymer comprises from about 18 to about 27 wt % of vinyl acetate. In certain embodiments of the invention, any of the at least one or more layers of the pouch comprise from an EAA copolymer in the concentrations as provided for the films further defined herein. In still other embodiments of the invention any such layers of the film may additionally comprises an EBA copolymer. Any of the one or more layers of the film may additionally comprise an antiblocking agent according to the concentrations as provided for the films further defined herein.

According to certain embodiments of the invention, it is desired that the film of the pouch has a modulus of less than about 15,000 psi, and, in particular, less than about 14,400 psi. In other embodiments of the invention, it is desired that the film of the pouch has a modulus of less than about 12,000 psi, and, in particular, less than about 10,000 psi. It is believed that the low modulus helps to provide flexibility to the pouch, impart softness to the pouch, and to attenuate the sound associated with the movement of the pouch.

As can be appreciated by those having ordinary skill in this art, the pouches of the present invention are not limited to a one-film structure or a three-film structure as described above. Pouches having any number of films, e.g., two, four, five, or more layers, are included within the scope of the present invention. For example, additional film(s) may be included in the pouch in order to enhance the strength, increase the moisture barrier capabilities of the pouch, reduce oxygen permeability, etc. if such additional properties are desired.

The films used for the inner film 16, the front panel 12, and the back panel 14 in manufacturing the multilayer pouch may include any of the films as described herein.

The films of the invention may include monolayer or multilayer films. A five-layer film in accordance with the present invention is illustrated in FIG. 5 and broadly designated by reference number 40. A five-layer film 40 includes a first exterior layer 42, a second exterior layer 44, and an interior layers 46-50 positioned between exterior layers 42 and 46. It should be noted, however, that additional layers, e.g., adhesive layers or additional function layers, such as barrier layers, may be included in film 40 as desired.

In one embodiment of the invention, the monolayer film or the at least one exterior layers 42, 44 of the multilayer film comprises a blend of at least one of a vinyl acetate copolymer, an acrylate copolymer, and any combination thereof and any one or more of a linear low density polyethylene (LLDPE), a low density polyethylene (LDPE), and a very low density polyethylene (VLDPE).

For example, the vinyl acetate copolymer may comprise an ethylene vinyl acetate (EVA) copolymer having varying concentrations of vinyl acetate. The vinyl acetate-derived units in the EVA copolymer are present in an amount ranging from about 2 to 40 percent by weight of the total. In an embodiment of the invention, the EVA copolymer comprises from about 18 to about 27 wt % of vinyl acetate. According to certain embodiments of the invention, the monolayer film or a layer of the multilayer film may comprise at least about 20 wt %, at least about 30 wt%, at least about 35 wt %, at least about 40 wt %, and at least about 50 wt % of at least one of a vinyl acetate copolymer, an acrylate copolymer, and any combination thereof. In certain embodiments of the invention, the monolayer film or a layer of the multilayer film comprises from about 17 to about 50 wt % of an EVA copolymer.

In certain embodiments of the invention, the film comprises from about 17 to about 50 wt %, from about 20 to about 50 wt %, from about 20 to about 40 wt %, and from about 40 to about 50 wt % of EVA copolymer. In certain other embodiments of the invention, the film comprises at least about 40 wt % of EVA copolymer.

A suitable EVA copolymer for use in the invention includes the V5510J resin supplied by the BASF-YPC joint venture in China having a vinyl acetate content of approximately 18 wt %. Additionally, ESCORENE™ Ultra LD 761.36 is a commercially available EVA copolymer that is supplied by ExxonMobil Chemical having a vinyl acetate content of approximately 26.7 wt %.

According to certain embodiments of the invention, each of the layers of a multilayer film may have varying compositions in order to impart suitable properties to the films. For example, in certain embodiments of the invention, an exterior layer of the film may include EBA or may have higher concentrations of EBA in order to promote bonding with a nonwoven fabric as further disclosed herein. Similarly, the compositions and blends of an exterior layer of the multilayer films may be formulated to impart desirable bonding strength among the layers such as, for example, using copolymers that favor thermal bonding or RF bonding techniques. As such, the films of the invention have the additional benefit of providing improved sealability among the films when used, for example, in the pouches of the invention.

In certain embodiments of the invention, as the concentration of acrylate copolymers is increased, the concentration of the EVA copolymer may be decreased. Suitable acrylate copolymers for use in the invention include ethylene acrylic acid (EAA), ethylene butyl acrylate (EBA), and ethylene methyl acrylate (EMA). NUCREL™ 3707 supplied by DuPont is a copolymer of ethylene and acrylic acid, which is suitable for use in the films of the invention. DuPont also supplies ELVALOY™ acrylate copolymers that can also be suitable for use in manufacturing the films of the invention.

Other suitable acrylate copolymers may include ethylene-co- n-butyl acrylate-co- carbon monoxide available from DuPont under the tradename ELVALOY™ HP771, ethylene-co- n-vinyl acetate-co-carbon monoxide available from DuPont under the tradename ELVALOY™ HP4924, and ethylene-co- n-butyl acrylate-co-glycidyl methacrylate available from DuPont under the tradename ELVALOY™ PTW.

According to certain embodiments of the invention, the monolayer film or a layer of the multilayer film comprises from about 7 to about 40 wt % of an EAA copolymer. In yet other embodiments of the invention, the monolayer film or a layer of the multilayer films comprises an EBA copolymer.

In certain embodiments of the invention, the film comprises from about 7 to about 40 wt %, from about 7 to about 36 wt %, and from about 7 to about 20 wt % of EAA copolymer. In certain other embodiments of the invention, the film comprises at least about 7 wt % of EAA copolymer.

In certain embodiments of the invention, when included, the EBA copolymer may range from about 20 to about 50 wt % in any layer of the film, but may desirably be included in the layers intended to bond with other layers or a nonwoven material. In certain other embodiments of the invention, when included, the EMA copolymer may be included in any amount up to about 50 wt % in any layer of the film.

Without intending to be limiting, generally, the peel strength of any seal increases as the amount the vinyl acetate (VA) , butyl acrylate (BA), or methyl acrylate (MA) content in the ethylene vinyl acetate or the ethylene acrylate copolymer increases. For example, a blend of an ethylene/alpha-olefin copolymer and an ethylene vinyl acrylate copolymer wherein the vinyl acrylate content in the ethylene acrylate copolymer is about 28 weight % will produce a RF seal having a greater peel strength than a similar blend in which the vinyl acrylate content is about 12 weight %. Accordingly, at lower levels of the VA, BA, or MA in the ethylene vinyl acetate or the ethylene acrylate copolymer, it may be desirable to include a higher content of the ethylene vinyl acetate or the ethylene acrylate copolymer in the overall blend.

A wide variety of ethylene/alpha-olefin (EAO) copolymers may be used in the practice of the present invention. The term "ethylene/alpha-olefin copolymer" generally designates copolymers of ethylene with one or more comonomers selected from C₃ to C₂₀ alp ha-ole fins, such as 1-butene, 1-pentene, 1-hexene, 1-octene, methyl pentene and the like, in which the polymer molecules comprise long chains with relatively few side chain branches. These polymers are obtained by low pressure polymerization processes and the side branching which is present will be short compared to non-linear polyethylenes (e.g., LDPE, a polyethylene homopolymer). The polyethylene polymers may be either heterogeneous or homogeneous.

Heterogeneous ethylene/alpha-olefin copolymers are ethylene/alpha-olefin

copolymerization reaction products of relatively wide variation in molecular weight and composition distribution, and which are prepared using conventional Ziegler-Natta or other heterogeneous catalysts. Examples of heterogeneous ethylene/alp ha-ole fins include linear low density polyethylene (LLDPE), linear medium density polyethylene (LMDPE), very low density polyethylene (VLDPE), and ultra-low density polyethylene (ULDPE). LLDPE is generally understood to include that group of heterogeneous ethylene/alpha-olefin

copolymers which fall into the density range of about 0.915 to about 0.94 g/cc. Sometimes linear polyethylene in the density range from about 0.926 to about 0.94 is referred to as LMDPE. Lower density heterogeneous ethylene/alpha-olefin copolymers are VLDPE

(typically used to refer to the ethylene/butene copolymers available from Union Carbide with a density ranging from about 0.88 to about 0.91 g/cc ) and ULDPE (typically used to refer to the ethylene/octene copolymers supplied by Dow). Suitable LLDPE for use in the inventive films includes the LL 1002 Series available from ExxonMobil. Additionally, LDPE is available from Qatar Petrochemicals, which is marketed under the name LOTRENE™ FD0274.

According to certain embodiments of the invention, the monolayer film or a layer of the multilayer film may comprise at least about 20 wt %, at least about 30 wt%, at least about 35 wt %, and at least about 40 wt % of any one or more of a LLDPE, a LDPE, and a VLDPE. In certain embodiments of the invention, a monolayer film or a layer of the multilayer film comprising a LLDPE and a LDPE will have a weight ratio of LLDPE to LDPE in a range from about 0.25 to about 2. Further pursuant to these certain embodiments, the weight ratio of LLDPE to LDPE may be about 1.0, about 1.05, or about 1.5.

In certain embodiments of the invention, the amount of LDPE included in a layer of the film ranges from about 0 to about 25 wt% and from about 7 to about 20 wt %. In certain embodiments of the invention, the amount of LLDPE included in a layer of the film ranges from about 0 to about 25 wt% and from about 7 to about 20 wt %. In certain embodiments of the invention, the amount of LLDPE included in a layer of the film ranges from about 0 to about 25 wt% and, when used, from about 15 to about 25 wt %. In certain embodiments of the invention, when used, the amount of VLDPE included in a layer of the film ranges from about 15 to about 40 wt% and, alternatively, from about 20 to about 30 wt %.

In certain embodiments of the invention, in particular for a film intended to be bonded to a nonwoven material, the composition and concentration of the layer intended to contact with and bond to the nonwoven material may desirably be formulated to achieve the preferred bonding properties. In one embodiment of the invention, the layer intended to bond with the nonwoven material comprises an EVA copolymer, an EAA copolymer, an EBA copolymer, and LDPE. Of course, the layer may additionally comprise other antiblock additives, stabilizers, etc. as further disclosed herein.

In an embodiment of the invention, the layer intended to bond with the nonwoven material comprises from about 15 to about 40 wt % EVA copolymer, from about 20 to about 30 wt % EVA copolymer, and from about 22 to about 25 wt % EVA copolymer. In certain embodiments of the invention, the layer intended to bond with the nonwoven material comprises from about 5 to about 25 wt % EAA copolymer, from about 10 to about 20 wt % EAA copolymer, and from about 12.5 to about 17.5 wt % EAA copolymer. In still other embodiments of the invention, the layer intended to bond with the nonwoven material comprises from about 25 to about 75 wt % EBA copolymer, from about 40 to about 60 wt % EBA copolymer, and from about 45 to about 55 wt % EBA copolymer. In still yet other embodiments of the invention, the layer intended to bond with the nonwoven material comprises from about 1 to about 25 wt % LDPE, from about 3 to about 20 wt % LDPE copolymer, and from about 5 to about 10 wt % LDPE copolymer. Stabilizers, antiblock agents, as well as other additives, may be included at any amount up to about 10 wt %, up to about 5 wt %, and up to about 4.5 wt %. In certain embodiments of the invention, an EMA polymer may be used in addition to or in replacement of, in whole or in part, of the amounts recited for the EBA copolymer.

In an exemplary embodiment of the invention, the layer intended to bond with the nonwoven material, which demonstrates a reasonably good bonding strength, comprises about 23.5 wt % EVA copolymer, about 15 wt % EAA copolymer, about 50 wt % EBA copolymer, about 7 wt % LDPE, about 2 wt % CaC0₃, and about 2.5 wt % of an antiblocking agent.

A multilayer film such as the five-layer film 40 exhibits a Young's modulus sufficient to withstand the expected processing, handling and use conditions for a wide variety of packaging applications.

In certain embodiments, the pouches of the invention have an odor permeation rate measured using the modified ISO 7229 test as further described herein of at most about 20,000 cm³/day-atm. In an embodiment of the invention, the film used for the front panel of a multilayer pouch has an odor permeation rate of at most about 47,000 cm³/day-atm while the film used for the back panel of a multilayer pouch has an odor permeation rate of at most about 23,300 cm³/day-atm.

EAOs are copolymers of ethylene and one or more alpha-olefins, the copolymer having ethylene as the majority mole-percentage content. In some embodiments, the comonomer includes one or more C₃-C₂₀ alpha-olefins, such as one or more C₄-Ci₂ alpha- olefins, or one or more C₄-Cs alpha-olefins. Particularly useful alpha-olefins include 1- butene, 1-hexene, 1-octene, and mixtures thereof. Useful EAOs include those having a density of less than about any of the following: 0.925, 0.922, 0.92, 0.917, 0.915, 0.912, 0.91, 0.907, 0.905, 0.903, 0.9, and 0.86 grams/cubic centimeter. Unless otherwise indicated, all densities herein are measured according to ASTM D1505.

As is known in the art, heterogeneous polymers have a relatively wide variation in molecular weight and composition distribution. Heterogeneous polymers may be prepared with, for example, conventional Ziegler Natta catalysts.

On the other hand, homogeneous polymers are typically prepared using metallocene or other single site-type catalysts. Such single-site catalysts typically have only one type of catalytic site, which is believed to be the basis for the homogeneity of the polymers resulting from the polymerization. Homogeneous polymers are structurally different from

heterogeneous polymers in that homogeneous polymers exhibit a relatively even sequencing of comonomers within a chain, a mirroring of sequence distribution in all chains, and a similarity of length of all chains. As a result, homogeneous polymers have relatively narrow molecular weight and composition distributions. Examples of homogeneous polymers include the metallocene-catalyzed linear homogeneous ethylene/alpha-olefin copolymer resins available from the Exxon Chemical Company (Baytown, TX) under the EXACT trademark, linear homogeneous ethylene/alpha-olefin copolymer resins available from the Mitsui Petrochemical Corporation under the TAFMER trademark, and long-chain branched, metallocene-catalyzed homogeneous ethylene/alpha-olefin copolymer resins available from the Dow Chemical Company under the AFFINITY trademark.

More particularly, homogeneous ethylene/alpha-olefin copolymers may be characterized by one or more properties known to those of skill in the art, such as molecular weight distribution (M_w/M_n), composition distribution breadth index (CDBI), narrow melting point range, and single melt point behavior. The molecular weight distribution (M_w/M_n), also known as "polydispersity," may be determined by gel permeation chromatography.

Homogeneous ethylene/alpha-olefin copolymers which can be used in the present invention generally have an M_w/M_n of less than 2.7; such as from about 1.9 to 2.5; or from about 1.9 to 2.3 (in contrast heterogeneous ethylene/alpha-olefin copolymers generally have a M_w/M_n of at least 3). The composition distribution breadth index (CDBI) of such homogeneous ethylene/alpha-olefin copolymers will generally be greater than about 70 percent. The CDBI is defined as the weight percent of the copolymer molecules having a comonomer content within 50 percent (i.e., plus or minus 50%) of the median total molar comonomer content. The CDBI of linear ethylene homopolymer is defined to be 100%. The Composition

Distribution Breadth Index (CDBI) is determined via the technique of Temperature Rising Elution Fractionation (TREF). CDBI determination may be used to distinguish homogeneous copolymers (i.e., narrow composition distribution as assessed by CDBI values generally above 70%) from VLDPEs available commercially which generally have a broad

composition distribution as assessed by CDBI values generally less than 55%. TREF data and calculations therefrom for determination of CDBI of a copolymer may be calculated from data obtained from techniques known in the art, such as, for example, temperature rising elution fractionation as described, for example, in Wild et. al, J. Poly. Sci. Poly. Phys. Ed., Vol. 20, p.441 (1982). In some embodiments, homogeneous ethylene/alpha-olefin copolymers have a CDBI greater than about 70%, i.e., a CDBI of from about 70% to 99%. In general, homogeneous ethylene/alpha-olefin copolymers useful in the present invention also exhibit a relatively narrow melting point range, in comparison with "heterogeneous copolymers", i.e., polymers having a CDBI of less than 55%. In some embodiments, the homogeneous ethylene/alpha-olefin copolymers exhibit an essentially singular melting point characteristic, with a peak melting point (T_m), as determined by Differential Scanning Calorimetry (DSC), of from about 60° C to 105° C. In one embodiment, the homogeneous copolymer has a DSC peak T_m of from about 80° C. to 100° C. As used herein, the phrase "essentially single melting point" means that at least about 80%, by weight, of the material corresponds to a single T_m peak at a temperature within the range of from about 60° C to 105° C, and essentially no substantial fraction of the material has a peak melting point in excess of about 115° C, as determined by DSC analysis. DSC measurements are made on a Perkin Elmer SYSTEM 7™ Thermal Analysis System. Melting information reported are second melting data, i.e., the sample is heated at a programmed rate of 10° C/min. to a temperature below its critical range. The sample is then reheated (2nd melting) at a programmed rate of 10° C/min.

A homogeneous ethylene/alpha-olefin copolymer can, in general, be prepared by the copolymerization of ethylene and any one or more alpha-olefin. For example, the alpha- olefin is a C3-C20 alpha-monoolefin, such as a C4-C12 or a C₄-Cs alpha-monoolefin. For example, the alpha-olefin comprises at least one member selected from the group consisting of butene-1, hexene-1, and octene-1, i.e., 1-butene, 1-hexene, and 1-octene, respectively, or a blend of hexene-1 and butene-1.

Processes for preparing and using homogeneous polymers are disclosed in U.S. Pat. No. 5,206,075, to HODGSON, Jr., U.S. Pat. No. 5,241,031, to MEHTA, and PCT

International Application WO 93/03093, each of which is hereby incorporated herein by reference thereto, in its entirety. Further details regarding the production and use of homogeneous ethylene/alpha-olefin copolymers are disclosed in PCT International

Publication Number WO 90/03414, and PCT International Publication Number WO

93/03093, both of which designate Exxon Chemical Patents, Inc. as the Applicant, and both of which are hereby incorporated herein by reference thereto, in their respective entireties.

Still another species of homogeneous ethylene/alpha-olefin copolymers is disclosed in U.S. Pat. No. 5,272,236, to LAI, et al, and U.S. Pat. No. 5,278,272, to LAI, et al, both of which are hereby incorporated herein by reference thereto, in their respective entireties. In one particular embodiment, the ethylene/alpha-olefm copolymer comprises a linear low density polyethylene (LLDPE) composed of copolymers of ethylene and comonomers of 1-butene. Desirably, the content of butene is from about 8 to 16 weight %. An exemplary commercially available LLDPE that can be used in accordance with the present invention is Sabic^® 518N or Sabic 118N available from Saudi Basic Industries Corporation.

An interior layer 36-40 may sometimes serve as a functional or core layer of the film. In certain embodiments of the invention, interior layer 36-40 is comprised of a material having barrier properties so that the film is substantially impervious to vapor and liquids. As noted above, embodiments of the multilayer film of the present invention include an interior layer positioned between the first and second exterior layers. Depending upon the particular application for which the multilayer film is to be used, the interior layer may provide additional desired properties, e.g., oxygen-barrier functionality, strength, RF sealability, or melt strength. In addition, the interior layer can serve to reduce the cost of the film by allowing less material to be used in the other layers of the film structure.

The total thickness of any of the films of the invention may range from about 1 to about 10 mils, alternatively, from about 3 to about 6 mils. The films used for the front panel 12 and the back panel 14 of the ostomy pouch 10 range in thickness from about 3 to about 10 mils, from about 5 to about 7 mils, and, in a certain embodiment, about 6 mils in thickness. The inner film 16 of the ostomy pouch 10 range from about 1 to about 5 mils, from about 2 to about 4 mils, and, in a certain embodiment, about 3 mils in thickness.

Exterior layers 36, 38, 40 of a multilayer film may provide from about 50 to about 90 percent, and about 60 to about 80 percent, of the total thickness of the film 40.

Adhesive layers may be provided that include any suitable adhesive material, such as, e.g., anhydride-modified EVA copolymer, anhydride-modified EMA copolymer, and anhydride-modified EBA copolymer, unmodified EVA, unmodified EMA and unmodified EnBA with comonomer content of about 6 to 30 weight %. Of the foregoing materials, anhydride-modified EVA copolymer may be desired, particularly in those embodiments where the vinyl acetate content thereof is 25 weight percent or more. For example, an exemplary material is "BYNEL CXA E-361" available from DuPont.

Adhesive layers may comprise a material selected from the group consisting of anhydride-modified EVA copolymer; anhydride-modified ethylene/acrylate copolymer (e.g., anhydride-modified EMA copolymer, anhydride-modified ethylene/ethyl acrylate copolymer, and anhydride-modified EBA copolymer); anhydride-modified ethylene/alpha-olefin (EAO) copolymer (e.g., anhydride-modified linear low density polyethylene and anhydride-modified very low density polyethylene); homogeneous ethylene/alpha-olefm copolymer, particularly those having a density of less than about 0.89 g/cc (e.g., ethylene/octene copolymer);

anhydride-modified high density polyethylene; and mixtures of the foregoing materials.

Suitable anhydride-modified EMA copolymers are commercially available from DuPont under the tradename BYNEL™, and from Quantum Chemicals under the tradename PLEXAPv™. Anhydride-modified linear low density polyethylene is commercially available from Mitsui under the tradename ADMER™, and from DuPont under the tradename

BYNEL™.

As can be appreciated by those having ordinary skill in this art, the multilayer films of the present invention are not limited to the five-layer structure described above. Films having fewer or greater numbers of layers, e.g., two, three, four, six, seven, eight, nine, or more layers, are included within the scope of the present invention. For example, additional high density polyethylene layer(s) may be included in the film in order to increase the moisture barrier capabilities of the film if such an increase is desired. Additional oxygen barrier layer(s) may also be included if desired.

Various additives may used in any or all of the layers of the multilayer films of the present invention. Such additives include, without limitation, antiblocking agents, antioxidants, processing aids such as calcium stearate, pigments, antistatic agents, etc. For example, CaC0₃ is a suitable blocking agent in certain embodiments of the invention.

Alternatively, a masterbatch, such POLYBATCH™ LCC 70, LCC 70 W, and LCC 80 W available from A. Schulman, may be used in compounding the resins used to form the films of the invention in order to impart antiblock properties and improve stability of the film. COSLIP™ 50 is another masterbatch available from Ampacet (Thailand). An

antiblocking/slip masterbatch suitable in certain embodiments of the inventive films include the AB SL PE 10N-ER5 available from Polytechs. This masterbatch reportedly contains 10% natural silica and 5% erucamide in a LDPE carrier resin and is compatible with all grades of PE and EVA. The recommended addition rate of this masterbatch material is in a range from about 1 to about 3 wt %.

Of course, additives can be included in any amounts, but in those embodiments of the invention when CaC0₃ is included in a layer of the film, the concentration of CaC0₃ ranges from about 0.5 to about 4 wt %, from about 1 to about 3 wt %, and about 2 wt % in the blend. Actual loading of CaC0₃, according to certain embodiments, in the slip agent may be less than 100%), for example, about 90%>, about 80%>, about 70%, or less. In those embodiments of the invention when an antiblocking agent is included in a layer of the film, the concentration of the antiblock agent may range from about 0.5 to about 4 wt % and from about 1 to about 2.5 wt %. Depending upon the masterbatch and/or additive used, the actual slip additive may be at loadings that are less than 100% of the amounts used. For example, there is about 20% slip agent in the Ampacet 101350-K. Additionally, some masterbatch formulations used, according to certain embodiments of the invention, may have slip and antiblock agents included as part of additive. For example, the AB SL PE 10N ER5 masterbatch supplied by Polytechs (France), used in certain embodiments of the invention, has from about 9 to about 11 wt % silica and from about 4.5 to about 5.5 wt % erucamide.

A. Schulman's POLYWHITE™ 8100, suitable for use in packaging materials, contain components that have been certified for contact with foods and the human body. Ti0₂ is a suitable pigment, in particular, in the films used for the back panel of the multifilm pouch. Where the monolayer or the multilayer film is to be used to for making medical solution pouches, the amount of additive included in the film may be minimized in order to reduce the likelihood that such additives will be extracted into the medical solution. In a layer of the film where pigmentation is desired to be included, the concentration of the pigment ranges from about 2 to about 25 wt %, from about 5 to about 20 wt %, and from about 10 to about 15 wt % of the pigment.

Without intending to be limiting, films that are intended to be clear may have a higher EVA copolymer concentration than films where a pigment has been included. In an embodiment of the invention, any layer of a film intended to be clear has an EVA copolymer concentration of at least about 30 wt %, at least about 35 wt %, at least about 40 wt %, and at least about 50 wt %. In an embodiment of the invention, films comprising a pigment that are not intended to be clear have an EVA copolymer concentration of at least about 15 wt %, at least about 20 wt %, and at least about 25 wt %.

The monolayer or multilayer films of the present invention can be formed by cast coextrusion as a tubular film. Containers for medical applications or other end uses can be made directly from the coextruded, tubular film, or alternatively from rollstock material obtained from the tube after it has been slit and ply-separated. A hot blown process can also be used to make the film. In certain embodiments of the invention, the films may be manufactured by a flat cast or round cast (downward extruded and water cooled) process. Exemplary equipment for use in the manufacturing process for the films of the invention may be available from JinMing (China) and the AQUAFROST™ blown film process available from Brampton Engineering (Canada). Other processes, such as extrusion coating, conventional lamination, slot die extrusion, etc., can also be used to manufacture the multilayer film of the present invention, although, without intending to be limiting, these alternative processes can be more difficult or less efficient than the above-recited methods. Embodiments of the invention can be heat sealed, such as with impulse heat sealing, RF sealed, and ultrasonic sealed.

The multilayer films of the present invention have been described in connection with medical applications, and in particular, ostomy pouches. However, it is to be understood that other applications for the films are also possible, and that this disclosure should not be construed as being limited only to medical pouches or devices.

The invention may be further understood by reference to the following examples, which are provided for the purpose of representation, and are not to be construed as limiting the scope of the invention.

EXAMPLES

Example 1

A pouch for containing fluids, such as medical fluids or bodily fluids, was considered according to the parameters in Table 1.

Table 1

Gauge, mil Blend, wt%

Layer Tarqet Actual EVA LLDPE LDPE VLDPE EAA EBA CaC03 a/b slip Ti02

A 0.92 48.5 — — 30.0 17.0 — 2.0 2.5 —

B 1 .04 40.0 — — 20.0 19.0 20.0 — 1 .0 —

C 1 .12 40.0 — — 20.0 19.0 20.0 — 1 .0 —

Front

D 1 .26 40.0 20.0 20.0 — 20.0 — — — —

E 0.97 38.5 20.0 20.0 — 17.0 — 2.0 2.5 —

Total 5.91 6.06

A 0.92 40.5 20.0 20.0 15.0 2.0 2.5

B 1 .04 40.0 20.0 10.0 — 18.0 — — — 12.0

C 1 .12 40.0 20.0 10.0 — 18.0 — — — 12.0

Back

D 1 .26 40.0 20.0 10.0 — 18.0 — — — 12.0

E 0.97 23.5 — 7.0 — 15.0 50.0 2.0 2.5 —

Total 5.91 6.26

A 0.49 20.5 20.0 19.0 36.0 2.0 2.5

B 0.55 20.5 20.0 20.0 — 37.0 — — 2.5 —

C 0.92 20.0 20.0 20.0 — 40.0 — — — —

Inner

D 0.67 17.5 20.0 20.0 — 40.0 — — 2.5 —

E 0.52 96.5 — — — - — 1 .0 2.5 —

Total 3.15 3.00 Tensile properties and the modulus of elasticity for each of the three films in both machine direction (MD) and transverse direction (TD) are provided in Table 2.

Table 2

Tensile Strength Elongation

at Break, psi at Break, % Modulus, psi

MD TD MD ID MD ID

Front Film 3,150 2,730 710 740 10,200 9,680

Back Film 3,190 2,760 720 750 12,800 12,700

Inner Film 3,720 3,120 600 650 13,700 14,400

The measurements for the tensile properties, elongation, and the modulus of Table 2 were performed in accordance with ASTM D882.

Impact strength of the films was evaluated and is reported in Table 3.

Table 3

Energy to Displacement

Peak Load, N Break Load, N Break, J at Break, mm

Front Film 58 58 1 .14 30.8

Back Film 68 68 0.91 23.6

Inner Film 32 32 0.36 20.0

The coefficient of friction for the abuse and sealant surfaces of each of the films was measured in accordance with ASTM D1894. The results are provided in Table 4.

Table 4

Coefficient of Friction

Static Kinetic

Method Peak Maximum Minimum Averaae

Abuse 0.29 0.23 0.19 0.21

Front Film

Sealant 0.22 0.17 0.15 0.16

Abuse 0.28 0.26 0.23 0.24

Back Film

Sealant 0.21 0.13 0.12 0.12

Abuse 0.20 0.14 0.12 0.13

Inner Film

Sealant 0.21 0.16 0.14 0.15

The moisture vapor transmission rate (MVTR), also water vapor transmission rate (WVTR), and the oxygen transmission rate (OTR) of the films of the invention may be measured according ASTM test methods F1249 and D3985, respectively. The measurements for MVTR and OTR of the exemplary front film, back film and inner film are provided in Table 5. Table 5

MVTR OTR

100°F/100% RH 73°F/0% RH

Specimen Gauge, mil gm/100 in² cc/m²

1 5.56 0.77 2,260

Front Film 2 5.87 0.75 2,340

3 5.72 0.80 2,220

1 6.13 0.57 1 ,620

Back Film 2 6.08 0.55 1 ,650

3 6.48 0.50 1 ,590

1 — — 3,155

Inner Film 2 — — 3,192

3 — — 2,775

Due to the very high OTR measurements at 0% relative humidity (RH), further tests at higher relative humidity were not performed. Additionally, odor barrier tests may be conducted using, for example, DIN 53380-3 (July 1998) entitled "Determining the Gas Transmission Rate of Plastic Film, Sheeting and Mouldings by the Carrier Gas Method" prepared by prepared by Technical Committee Kunststoff-Folien und kunststoffbeschichtete

Flachengebilde (Kunstleder); allgemeine Eigenschaften of the Normenausschufi Kunststoffe (Plastics Standards Committee), which is based somewhat on the ASTM D3985 (1995) test standard.

The films were heat sealed at 235°F. The seal strength results measured for the exemplary films are shown in Table 6.

Table 6

Maximum Load, Ibf Energy to Break, Ibf-in

Average StdDev Average StdDev

Front Film 5.26 0.24 46.8 4.35

Back Film 5.80 0.36 20.4 3.02

Inner Film 5.20 0.36 32.9 2.42

Seal strengths having a maximum load of 5 lbf, in some embodiments, are desirable.

Odor barrier test on the front film and the back film samples were conducted using a modified ISO 7229 test using ammonia gas at ambient pressure with an exposed area of 119 cm² and a collection medium of nitrogen gas at 100 ml/min. The ammonia concentration was determined using off-line infrared gas spectroscopy using a 10 cm path length cell and a Nicolet 400D FTIR spectrometer at 1 cm^"1 resolution. The measurement results for three separate trials are shown in Table 7. Table 7

Permeation Rate Time to Stable

Gauge, mil cm³/day-atm Level, h

1 2 3

Front Film 5.5 47,000 45,000 46,500 2

Back Film 5.9 20,600 20,000 23,300 2

Example 2

Another embodiment of a pouch for containing fluids, such as medical fluids or fluids, was constructed using five-layer films according to the parameters in Table 8.

Table 8

Gauge, mil Blend, wt%

Film Laver EVA LLDPE LDPE EAA EBA CaC03 a/b slip Ti02

A 0.92 40.0 20.0 20.0 17.0 — 2.0 1 .0 —

B 1 .04 40.0 20.0 20.0 20.0 — — — —

Front C 1 .72 40.0 20.0 20.0 20.0 — — — —

D 1 .26 40.0 20.0 20.0 20.0 — — — —

E 0.97 40.0 20.0 20.0 17.0 ~ 2.0 1 .0 ~

A 0.92 40.5 20.0 20.0 15.0 2.0 2.5

B 1 .04 40.0 20.0 10.0 18.0 — — — 12.0

Back C 1 .72 40.0 20.0 10.0 18.0 — — — 12.0

D 1 .26 40.0 20.0 10.0 18.0 — — — 12.0

E 0.97 23.5 — 7.0 15.0 50.0 2.0 2.5 —

A 0.49 20.5 20.0 19.0 36.0 2.0 2.5

B 0.55 20.5 20.0 20.0 37.0 — — 2.5 —

Inner C 0.92 20.0 20.0 20.0 40.0 — — — —

D 0.67 17.5 20.0 20.0 40.0 — — 2.5 —

E 0.52 96.5 — — — — 1 .0 2.5 —

According to this embodiment, the outer layer of the film of the back panel, Back-E, had a high content of EBA copolymer in order to promote bonding with a nonwoven material. However, it was found that this formulation was not as favorable in promoting bonding with a nonwoven material. Note also the construction of the other external layers (Front-E, Back- A, and Inner- A) in order to promote thermal sealing between each of the layers.

Example 3

Yet another embodiment of a pouch for containing fluids, such as medical fluids or bodily fluids, was constructed using five-layer films according to the parameters in Table 9. Table 9

Gauge, mil Blend, wt%

Film Laver EVA LDPE EAA EMA CaC03 a/b slip Ti02

A 0.97 25.0 7.0 15.0 50.0 2.0 1 .0 —

B 1 .04 25.0 9.0 15.0 50.0 — 1 .0 —

Front C 1 .72 25.0 9.0 15.0 50.0 — 1 .0 —

D 1 .26 25.0 9.0 15.0 50.0 — 1 .0 —

E 0.92 25.0 7.0 15.0 50.0 2.0 1 .0

A 0.97 25.0 7.0 15.0 50.0 2.0 1 .0

B 1 .04 25.0 — 12.0 50.0 — 1 .0 12.0

Back C 1 .72 25.0 — 12.0 50.0 — 1 .0 12.0

D 1 .26 25.0 — 12.0 50.0 — 1 .0 12.0

E 0.92 25.0 7.0 15.0 50.0 2.0 1 .0

A 0.52 25.0 7.0 15.0 50.0 2.0 1 .0

B 0.55 25.0 9.0 15.0 50.0 — 1 .0 —

Inner C 0.92 25.0 9.0 15.0 50.0 — 1 .0 —

D 0.67 25.0 9.0 15.0 50.0 — 1 .0 —

E 0.49 25.0 7.0 15.0 50.0 2.0 1 .0 —

The blend for the outer layer E of the film used in the back panel showed an improved bonding strength with a nonwoven fabric, yet not as good as that demonstrated for the same layer shown in Table 1.

Example 4

Another embodiment of a pouch for containing fluids, such as medical fluids or bodily fluids, was constructed using five-layer films according to the parameters in Table 10.

Table 10

Gauge, mil Blend, wt%

Film Laver EVA LLDPE LDPE EAA EBA CaCQ3 a/b slip Ti02

A 0.97 40.0 20.0 20.0 17.0 2.0 1.0 —

B 1.04 40.0 20.0 20.0 20.0 - -

Front C 1.72 40.0 20.0 20.0 20.0 — —

D 1.26 40.0 20.0 20.0 20.0 — —

E 0.92 40.0 20.0 20.0 17.0 2.0 1.0 -

A 0.97 23.0 — 7.0 15.0 50.0 2.0 3.0 —

B 1.04 40.0 20.0 10.0 18.0 — 12.0

Back C 1.72 40.0 20.0 10.0 18.0 — 12.0

D 1.26 40.0 20.0 10.0 18.0 — 12.0

E 0.92 40.0 20.0 20.0 15.0 2.0 3.0 -

A 0.52 96.0 1 .0 3.0

B 0.55 20.0 20.0 20.0 37.0 3.0 —

Inner C 0.92 20.0 20.0 20.0 40.0 — —

D 0.67 17.0 20.0 20.0 40.0 3.0 —

E 0.49 20.0 20.0 19.0 36.0 2.0 3.0 —

The blend for the outer layer A of the film used in the back panel demonstrated favorable bonding strengths with nonwoven fabrics. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

THAT WHICH IS CLAIMED:

1. A pouch comprising a film interconnected to define a cavity configured to contain a fluid, the film having one or more layers comprising:

at least about 40 wt % of at least one of a vinyl acetate copolymer, an acrylate copolymer, and any combination thereof; and

any one or more of a LLDPE, a LDPE, and a VLDPE.

2. The pouch according to claim 1, wherein the film comprises two longitudinal side edges, the film is folded to form opposing side edges of the pouch, and the opposing side edges are sealed to each other to form a vertical seam that extends longitudinally along a length of the pouch to define the cavity.

3. The pouch according to claim 1, wherein any of the at least one or more layers comprises at least about 40 wt % of an EVA copolymer.

4. The pouch according to claim 3, wherein the EVA copolymer comprises from about 18 to about 27 wt % of vinyl acetate.

5. The pouch according to claim 1, wherein any of the at least one or more layers comprises from about 7 to about 40 wt % of an EAA copolymer.

6. The pouch according to claim 1, wherein any of the at least one or more layers additionally comprises an EBA copolymer.

7. The pouch according to claim 1, wherein any of the at least one or more layers additionally comprises an antiblocking agent.

8. The pouch according to claim 1, wherein the film has a modulus of less than about 14,400 psi.

9. A multifilm pouch comprising:

an inner film interconnected to define a cavity configured to contain a fluid; a front panel and a back panel arranged in opposing face-to-face relation; and a top end, a bottom end, and a pair of opposing side edges extending longitudinally between the top end and the bottom end,

wherein the front panel and the back panel are fixedly joined to the inner film and are adheredly joined to each other along their adjacent peripheral edges to form a seam at the opposing side edges.

10. The multifilm pouch according to claim 9, the inner film having one or more layers comprising:

at least about 40 wt % of at least one of a vinyl acetate copolymer, an acrylate copolymer, and any combination thereof; and any one or more of a LLDPE, a LDPE, and a VLDPE.

11. The multifilm pouch according to claim 9, wherein the front panel comprises a film having one or more layers comprising:

any one or more of a LLDPE, a LDPE, and a VLDPE.

12. The multifilm pouch according to claim 11, the film additionally comprising an EBA copolymer.

13. The multifilm pouch according to claim 11, wherein the back panel comprises another film having one or more layers comprising:

any one or more of a LLDPE, a LDPE, and a VLDPE.

14. The multifilm pouch according to claim 13, wherein any of the one or more layer of the another film comprises a pigment.

15. The multifilm pouch according to claim 9, wherein the front panel and the back panel are unconnected along the top end to allow for filling of the multifilm pouch.

16. The multifilm pouch according to claim 9, wherein the front panel and the back panel include inner surfaces that are heat sealed to each other along the bottom end of the multifilm pouch.

17. The multifilm pouch according to claim 9, wherein the inner film is a single sheet having two longitudinal side edges, wherein the sheet material is folded to form opposing side edges of an inner portion of the multifilm pouch, and the opposing side edges are sealed to each other to form a vertical seam that extends longitudinally along a length of the inner portion to define the cavity.

18. The multifilm pouch according to claim 17, wherein the vertical seam comprises a fin seal.

19. The multifilm pouch according to claim 9, wherein a nonwoven fabric is adheredly joined to an outer surface of the back panel.

20. The multifilm pouch according to claim 9, wherein the fluid is a medical fluid or a bodily fluid.

21. The multifilm pouch according to claim 9, wherein the multifilm pouch is an ostomy pouch.

22. A film comprising at least one layer having: at least about 40 wt % of at least one of a vinyl acetate copolymer, an acrylate copolymer, and any combination thereof; and

any one or more of a LLDPE, a LDPE, and a VLDPE,

wherein the film has a modulus less than about 14,400 psi.

23. The film according to claim 22, wherein the at least one layer comprises from about 17 to about 50 wt % of an EVA copolymer.

24. The film according to claim 23, wherein the EVA copolymer comprises from about 18 to about 27 wt % of vinyl acetate.

25. The film according to claim 22, wherein the at least one layer comprises from about 7 to about 40 wt % of an EAA copolymer.

26. The film according to claim 22, the at least one layer additionally comprising an EBA copolymer.

27. The film according to claim 22, the at least one layer having at least about 20 wt % of any one or more of a LLDPE, a LDPE, and a VLDPE.

28. The film according to claim 22, the at least one layer additionally comprising an antiblocking additive.

29. The film according to claim 22, wherein the film is a monolayer film.

30. A multilayer film comprising

a first exterior layer having:

at least about 40 wt % of at least one of a vinyl acetate copolymer, an acrylate copolymer, and any combination thereof, and

any one or more of a LLDPE, a LDPE, and a VLDPE; and

a second exterior layer.

31. The multilayer film according to claim 30, wherein the first exterior layer comprises from about 20 to about 50 wt % of an EVA copolymer.

32. The multilayer film according to claim 31 , wherein the EVA copolymer comprises from about 18 to about 27 wt % of vinyl acetate.

33. The multilayer film according to claim 30, wherein the first exterior layer comprises from about 7 to about 36 wt % of an EAA copolymer.

34. The multilayer film according to claim 30, wherein the first exterior layer additionally comprises an antiblocking agent.

35. The multilayer film according to claim 30, additionally comprising at least one interior layer having: at least about 40 wt % of at least one of a vinyl acetate copolymer, an acrylate copolymer, and any combination thereof; and

any one or more of a LLDPE, a LDPE, and a VLDPE.

36. The multilayer film according to claim 35, wherein the at least one interior layer comprises at least about 40 wt % of an EVA copolymer.

37. The multilayer film according to claim 35, wherein the at least one interior layer comprises from about 7 to about 40 wt % of an EAA copolymer.

38. The multilayer film according to claim 35, wherein the at least one interior layer additionally comprises an EBA copolymer.

39. The multilayer film according to claim 35, wherein the at least one interior layer additionally comprises an antiblocking agent.

40. The multilayer film according to claim 30, wherein the second exterior layer comprises:

any one or more of a LLDPE, a LDPE, and a VLDPE.

41. The multilayer film according to claim 40, wherein the second exterior layer comprises from about 20 to about 40 wt % of an EVA copolymer.

42. The multilayer film according to claim 40, wherein the second exterior layer comprises from about 7 to about 20 wt % of an EAA copolymer.

43. The multilayer film according to claim 40, wherein the second exterior layer additionally comprises an EBA copolymer.

44. The multilayer film according to claim 40, wherein the second exterior layer additionally comprises an antiblocking agent.

45. The multilayer film according to claim 30, wherein the multilayer film has a modulus of less than about 14,400 psi.