Barrier laminates

Abstract

The present invention provides a barrier film comprising a first layer formed of a thermoplastic polyurethane (TPU) and a second layer formed of a thermoplastic polymer-based coupling agent, the coupling agent containing an ethylene-vinyl acetate (EVA) copolymer and a second polar comonomer polymer, wherein the barrier film has a total thickness of 50 µm (2 mils) to 600 µm (24 mils), wherein the first layer has a thickness of 20 µm (0.8 mils) to 400 µm (16 mils), and wherein the second layer has a thickness of 20 µm (0.8 mils) to 200 µm (8 mils). The barrier film of the present invention can be used in colostomy bags, urethrostomy bags, and ileostomy bags, as well as other medical applications.

Description

Field of the Invention

[0001] The present invention relates generally to films and more particularly to barrier films for use in ostomy bags and other medical applications. Background of the Invention

[0003] The complex demands of applications in the medical field often require combining the advantageous properties of various materials. This can be hindered by the limited compatibility of different polymers.

[0004] Medical barrier films are often designed to address quality of life issues for people whose medical history / condition requires the use of a stoma (eg, colostomy, urethrostomy, and ileostomy) bag or other collecting bag.

[0005] In such cases, barrier properties are important to keep any unpleasant odors and moisture inside the bag while the bag is worn. In addition, such films provide excellent performance in terms of sealing ability and seal integrity, liquid and gas barriers, mechanical integrity and dimensional stability. Ostomy bags produced from barrier materials typically contain polyvinylidene chloride (PVDC) as a barrier material.

[0006] In the past, polyethylene has been the preferred choice for the outer layer; a more recent development is the use of ethylene / vinyl acetate copolymer (EVA) to increase the flexibility of the bag itself.

[0007] Bagging systems typically consist of a collection bag and a plastic bag. Simple bagging systems are one-piece systems, while more complex two-piece systems involve a mounting plate, usually called a flange, wafer or base plate, and a collection bag that is attached mechanically or with an adhesive to create an airtight seal.

[0008] The main requirements for materials considered for the construction of ostomy bags are flexibility, odor barrier, low weight and comfort against the skin. These requirements are usually met in existing laminates by combining a barrier film, which can be a single layer or a multilayer structure, typically 60µm to 100µm thick, with a skin contact substrate (e.g., a nonwoven fabric) that is secured to the barrier film by a peripheral bag seal.

[0009] Medical device materials must also exhibit the appropriate barrier properties necessary to maintain the proper composition of the fluids that interact with these materials, ensuring that oxygen, moisture, and potential contaminants cannot penetrate the membrane or tubing. Regardless of the rigidity of the device, these devices must also possess the durability to withstand the rigors and fast pace of the medical environment. Finally, medical devices must be made from materials that have demonstrated a clear history of biocompatibility.

[0010] There is a need in the art for better barrier films that combine the beneficial properties of thermoplastic polyurethanes with the beneficial properties of olefinic-based materials. SUMMARY OF THE INVENTION

[0012] Thus, the present invention provides a barrier film that allows a thermoplastic polyurethane (TPU) based material to be combined with an olefinic material.In order to overcome potential detrimental adhesion defects between the olefinic outer layer and the polyurethane (PU) layer of the barrier film, a specific bridging layer is also provided.

[0013] These and other advantages and benefits of the present invention will be apparent from the following detailed description of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will now be described, for purposes of illustration and not limitation, with reference to the accompanying drawings, in which:

[0016] Figure 1 A cross-sectional view of a barrier film of the present invention is shown. DETAILED DESCRIPTION OF THE INVENTION

[0018] The invention will now be described for purposes of illustration and not limitation.Except in the operating examples, or where otherwise indicated, all numerical values ​​expressing quantities, percentages, etc. in this specification are to be understood as being modified in all instances by the term "about".

[0019] Any numerical range described in this specification is intended to include all sub-ranges of the same numerical precision included in the range. For example, the range of "1.0 to 10.0" is intended to include all sub-ranges between the minimum value 1.0 and the maximum value 10.0 (including the end value), that is, the minimum value is equal to or greater than 1.0 and the maximum value is equal to or less than all sub-ranges of 10.0, such as 2.4 to 7.6. Any maximum numerical limit described in this specification is intended to include all lower numerical limits contained therein, and any minimum numerical limit described in this specification is intended to include all higher numerical limits contained therein. Therefore, the applicant reserves the right to modify this specification (including claims) to explicitly narrate any sub-range included in the scope clearly recorded herein. All these ranges are intended to be inherently described in this specification so that the modification of any such sub-range clearly recorded meets the requirements of 35 USC §112 (a) and 35 USC §132 (a). The various embodiments disclosed and described in this specification may include the features and characteristics described in various ways herein, be composed of the features and characteristics, or be substantially composed of the features and characteristics.

[0020] Unless otherwise stated, any patent, publication or other public material identified herein is incorporated by reference in its entirety into this specification, but only to the extent that the incorporated material does not conflict with existing definitions, statements or other public materials clearly set forth in this specification. Thus, and to the extent necessary, the explicit disclosures set forth in this specification replace any conflicting material incorporated by reference herein. Any material or portion thereof incorporated by reference into this specification but conflicting with existing definitions, statements or other public materials set forth herein is incorporated only to the extent that there is no conflict between the incorporated material and the existing public materials. The applicant reserves the right to amend this specification to expressly record any subject matter or portion thereof incorporated by reference herein.

[0021] References throughout this specification to "various non-limiting embodiments," "certain embodiments," etc., are intended to indicate that a particular feature or characteristic may be included in one embodiment. Thus, the use of the phrases "in various non-limiting embodiments," "certain embodiments," etc., in this specification does not necessarily refer to a common embodiment, but may refer to different embodiments. Furthermore, particular features or characteristics may be combined in any suitable manner in one or more embodiments. Thus, particular features or characteristics illustrated or described in conjunction with various or certain embodiments may be combined in whole or in part with features or characteristics of one or more other embodiments without limitation. Such modifications and variations are intended to be included within the scope of this specification.

[0022] Unless otherwise indicated, the grammatical articles "a", "an", and "the" as used herein are intended to include "at least one" or "one or more", even though in some cases "at least one" or "one or more" is explicitly used. Thus, these articles are used in this specification to refer to one or more than one (i.e., "at least one") of the grammatical objects of the article. For example, and not limitation, "a component" means one or more components, and thus, feasibly, more than one component is contemplated and may be employed or used in the implementation of the described embodiments. Furthermore, unless the context requires otherwise, the use of a singular noun includes the plural, and the use of a plural noun includes the singular.

[0023] In a first aspect, the present invention is directed to a barrier film comprising a first layer formed of a thermoplastic polyurethane (TPU) and a second layer formed of a heat activated olefin-based polymer coupling agent containing at least an ethylene-vinyl acetate (EVA) copolymer and a second polar comonomer, wherein the packaging material has a total thickness of 2 mils (50 µm) to 24 mils (600 µm), the first layer has a thickness of 0.8 mils (20 µm) to 16 mils (400 µm), and the second layer has a thickness of 0.8 mils (20 µm) to 8 mils (200 µm). The barrier film of the present invention may find use in stoma (e.g., colostomy, urethrostomy, and ileostomy) bags and other medical applications.

[0024] In a second aspect, the invention relates to a method of constructing an ostomy bag, the method comprising: combining an olefinic film with a barrier film to form a multilayer film, the barrier film comprising a first layer formed of a thermoplastic polyurethane (TPU) and a second layer formed of a heat-activated olefin-based polymer coupling agent, the coupling agent containing at least an ethylene-vinyl acetate (EVA) copolymer and a second polar comonomer, wherein the packaging material has a total thickness of 2 mils (50µm) to 24 mils (600µm), the first layer has a thickness of 0.8 mils (20µm) to 16 mils (400µm), and the second layer has a thickness of 0.8 mils (20µm) to 8 mils (200µm), and forming a bag comprising a first wall and a second wall bonded together to define a closed compartment having an interior from the multilayer film.

[0025] Of particular interest in the present invention is the combination of elastomers with barrier materials.Laminar films are provided to bridge the adhesion properties between polyurethane (PU) and barrier films available in the art.

[0026] The barrier film of the present invention may comprise two layers, or preferably more layers. Conventional gas and odor barrier materials may be used, for example vinylidene chloride copolymers with comonomers such as acrylates, acrylic acid and vinyl chloride, or ethylene-vinyl alcohol copolymers, or vinylidene fluoride-vinyl fluoride copolymers, or polyamides, or mixtures thereof, optionally with the addition of chlorinated paraffins, stabilizers and waxes.

[0027] The structuring process may include a PVDC (polyvinylidene chloride) layer embedded between polyolefin layers.Preferred coextruded films include PVDC and also include an EVA (ethylene-vinyl alcohol) copolymer layer (eg, PVDC / EVA film), in particular EVA / PVDC / EVA.

[0028] Films comprising EVA (ethylene vinyl alcohol) copolymers and preferably also comprising an EVA layer are also of interest, preferably EVA / Tie / EVOH / Tie / EVA barrier materials. The "Tie" layer may preferably be selected from modified EVA films.

[0029] Furthermore, the use of EVA as the outer layer allows for sealing methods such as high frequency welding.

[0030] The materials involved in the anti-odor multilayer structure are described in, for example, U.S. Patent No. 5,470,624. The material suitable for skin contact is selected to be as discrete as possible, for example by its soft touch and low noise or quietness. Highly tough materials from the polyurethane group provide these properties. In addition, the flexibility of the stoma bag structure is considered to be increasingly important because of the need for highly elastic opening structures (apertures) of adhesives, flanges or bags.

[0031] Processing techniques include application and lamination of adhesives, or in the case of flange welding reasonably far away from the bag opening structure, so that the opening structure can be stretched and formed into the desired shape and size.

[0032] For those skilled in the art, polyurethane materials are well known for their versatility and suitability for forming materials ranging from adhesives, foams to solid elastomers. Adhesives suitable for medical applications can be formed, for example, from polyurethane dispersions. Solid elastomers can be selected, for example, from thermoplastic polyurethanes (TPU) classes.

[0033] For those skilled in the art, thermoplastic polyurethane (TPU) is well known for its wear-resistant and stable properties and can provide solutions for bags / packs, nested blister packaging and composite blister packaging. TPU is a strong material, and TPU products show high tear strength and tear resistance, durability (even for soft grades), good chemical resistance, ideal transparency, important abrasion resistance, and excellent low temperature performance. Bags composed only of TPU do not provide sufficient barrier properties for small-gauge films.

[0034] The exterior of the ostomy bag must be durable enough to resist puncture, but must still exhibit adequate barrier properties to control the spread of odor. Tensile strength is necessary to resist bursting, tearing, and cutting. Thermoplastic polyurethane (TPU) gives the product elasticity and is desirable for applications with mechanical risks.

[0035] Thermoplastic polyurethanes (TPUs) are flexible over a wide temperature range without the use of plasticizers, and their base chemistry allows them to be tailored to specific needs. Eliminating the use of plasticizers can help reduce the risk of health complications known to be caused by such chemicals.

[0036] Specifically, thermoplastic polyurethane (TPU) formulations can be created to suit the medical industry's requirements, keeping in mind that no plasticizers are involved in TPU production, and the material does not leach any harmful byproducts. Thermoplastic polyurethane (TPU) is well known for its reliability in the medical field, and selected formulations have long been proven to be biocompatible.

[0037] For those skilled in the art, thermoplastic polyurethane (TPU) is well known for its skin-friendliness and biocompatibility, and can be processed using thermoplastics such as welding and sealing. To ensure the longevity of medical products, easy sealing is necessary. Technologies such as ultrasonic and solvent welding provide more efficient and consistent welding quality than previously used methods.

[0038] Due to its customizable nature, thermoplastic polyurethane (TPU) is an ideal material for constructing a variety of medical devices, such as tubes and fluid storage bags. The safety of TPU products with respect to their use on or in the human body is important, as medical products must often deliver drugs, blood, or other fluids, and therefore the materials used in their development must not leach any harmful substances that could leach into these fluids and compromise the integrity of the fluids.

[0039] Thermoplastic polyurethane (TPU) is also considered the material of choice for flanges and opening structures in medical devices.

[0040] Polyurethane dispersions are the materials of choice for forming skin-friendly adhesive layers with an adhesive strength that can be adjusted to the application requirements. Thus, tailored formulations are created in the medical field.

[0041] The present invention provides a solution in the form of a multilayer composite film structure intended to be laminated or sealed to a barrier material. Such a laminate can then be laminated, welded or overmolded with a thermoplastic polyurethane (TPU) based material to form a flange or opening structure. Alternatively, the film according to the present invention can be coated with other polyurethane materials in advance.

[0042] like Figure 1 As shown in , the composite film according to the present invention comprises a first layer 1 substantially comprising thermoplastic polyurethane (TPU) and a second layer 2 comprising at least one modified ethylene-vinyl acetate (EVA) copolymer.

[0043] In some embodiments, layer 2 comprises ethylene-vinyl acetate (EVA) copolymer modified by thermoplastic polyurethane (TPU), and the adhesion to different polymers is improved by blending both TPU and EVA. This blending method provides excellent adhesion properties for bonding to TPU and rigid thermoforming polymers. In this embodiment, the film according to the present invention contains at least one TPU / EVA blend layer.

[0044] The second layer 2 contains polar comonomers, such as disclosed in U.S. Patent No. 5,593,775. Preferably, ethylene is a comonomer. In the packaging material according to the present invention, at least two different polar oxygen-containing olefin copolymers A and B are mixed and melted together under sufficient shearing. In various embodiments, relative to the gross weight of the polymer resin used, the total proportion of polar oxygen-containing comonomer units is 18 wt % to 40 wt %. Olefin comonomer A should be present in a larger amount, and its total proportion is at least 60% of the total weight of the comonomer units. In certain embodiments, the comonomers used for polar olefin copolymers A and B are methacrylic acid and / or its salt and / or its ester, and / or acrylic acid and / or its salt and / or its ester, and / or vinyl acetate in unsaponified and / or saponified form.

[0045] Thermoplastic polyurethane (TPU) ether-based films are preferred over TPU ester-based films due to their improved hydrolysis resistance.

[0046] For making multilayer structures, known thermoforming methods for processing plastic materials are suitable. In particular, for higher levels of bond strength between the layers, coextrusion techniques are suitable and preferred. Blown film coextrusion is a particularly preferred method for producing films according to the invention.

[0047] Furthermore, coextrusion manufacturing of films comprising a normal thermoplastic polyurethane (TPU) layer facing one surface and at least one TPU / EVA layer facing the other surface for bonding purposes improves performance. The coextrusion process provides the option for further bridging by combining with additional layers.

[0048] Thermoplastic polyurethane (TPU) and ethylene vinyl acetate (EVA) can be used in thermoplastic technology due to their combined processing window. This makes them suitable partners for enhancing adhesion properties. This combined thermoplastic window can be used in film extrusion processes, allowing coextrusion of individual layers at temperatures between 160°C and 200°C as well.

[0049] During the manufacturing process, the membrane may be surface treated so that at least one of the outer layers has been chemically or physically treated.

[0050] Ethylene vinyl acetate (EVA) modified adhesives provide improved adhesion properties between thermoplastic polyurethane (TPU) and structured olefin surfaces. Adhesion properties can be introduced by inserting an adhesive layer between the TPU and the olefin, or by blending the TPU with the olefin. In another embodiment, this can be accomplished by providing a bridged second layer 2 that is compatible by blending the TPU with EVA and having a TPU surface layer.

[0051] For a blending ratio of 0.3 to 3.0 mass% of TPU / EVA, the adhesion property of the second layer 2 exhibits the most suitable performance. Preferably, the blending ratio between TPU and modified EVA is 0.7 to 1.5 mass%.

[0052] Additional improvement can be obtained by selecting maleic anhydride (MSA) as the modifying component of ethylene vinyl acetate (EVA). The EVA MSA terpolymer can be a random copolymer or, more preferably, MSA can be grafted to the EVA backbone to provide further improvement. A preferred embodiment is a film consisting of at least two layers: a layer 1 formed of TPU to provide wear stability and a layer 2 formed of a TPU / EVA blend to provide adhesion.

[0053] In some embodiments, the coupling material resin used for the second layer 2 contains ethylene, vinyl acetate and maleic anhydride as comonomers, wherein the total amount of maleic anhydride used for the coupling material does not exceed 5000 ppm.

[0054] The first layer 1 of the film according to the present invention comprises at least one TPU elastomer, preferably a linear TPU elastomer, whose long-chain diol component is a polyether or a polyester, and preferably has a Shore A hardness of 75-95 measured according to ASTM D 2240.

[0055] The film according to the present invention may be laminated or welded directly adjacent to or reasonably remote from the opening structure of the bag to enable the opening structure to be stretched and formed into a desired shape and size.

[0056] In some embodiments, the thermoplastic composite film according to the present invention is laminated to the olefinic outer side of the barrier film with a size larger than the opening structure. Thus, by being stretched and formed to the desired size, the risk of failure of the laminate can be avoided.

[0057] The film according to the invention can also be coated with a preferably polyurethane-based adhesive and subsequently sealed to current state-of-the-art barrier films.

[0058] For the multilayer structure according to the present invention, TPU ether-based film layers are preferred over TPU ester-based film layers due to their improved hydrolysis resistance.

[0059] Suitable thermoplastic polyurethanes are available, for example, under the trade names DESMOPAN, ELASTOLLAN, ESTANE, MORTHANE and TEXIN.

[0060] The film according to the invention contains in the first (TPU) layer 1 additional processing additives from substances including but not limited to:

[0061] I. Anti-blocking agent, inorganic or organic spacer;

[0062] II. Slip aids or release aids, usually surface-active;

[0063] III. Pigments or fillers; and

[0064] IV. Stabilizers.

[0065] In selected embodiments, the total amount of Additives I to IV is from 0% to 30%, and in certain embodiments, the total amount is >0% to 30%.

[0066] In various embodiments, the film has a total thickness of 2 mils (50 µm) to 24 mils (600 µm). In these embodiments, the first (TPU) layer 1 has a layer thickness of 0.8 mils (20 µm) to 16 mils (400 µm), and the second (blend) layer 2 has a thickness gauge of 0.8 mils (20 µm) to 8 mils (200 µm).

[0067] The film according to the invention can be used to bridge otherwise incompatible polymeric materials.The film can be laminated to flexible plastic materials and the film is advantageously obtainable by various heat and solvent based sealing methods.

[0068] In addition to ostomy bags, another application of the films of the present invention is for combining olefinic barrier films and three-dimensional thermoplastic polyurethane (TPU) parts together.Preferred welding flange and opening structures are flat structures extruded from TPU. Example

[0069] The following non-limiting and non-exhaustive examples are intended to further describe various non-limiting and non-exhaustive embodiments without limiting the scope of the embodiments described in this specification. Unless otherwise indicated, all quantities given in "parts" and "percents" are understood to be by weight.

[0070] The following examples and comparative examples were produced by blown film extrusion. Kunststoffe (84 (1994) 1131-1138), Pearson Mechanics of Polymer Processing (Elsevier Publishers, New York, 1985), or Davis-Standard Company, Paper, Film & Foil Converter Extrusion processes suitable for processing thermoplastic materials are described in Rauwendaal 64 (1990), pp. 84-90. Polymer Extrusion(Hanser Publishers, New York 1986), or Michaeli in Extrusions-Werkzeuge (Hanser Verlag, Munich 1991) describes a blown film tool for forming the melt into a film shape.

[0071] Example 1

[0072] A coextruded film was produced using a two-layer blown film die, comprising a first layer formed of a thermoplastic polyurethane (TPU)-ether having a Shore A-hardness of 89 measured according to ASTM D2240, equivalent to a Shore-D of 36. The TPU-ether had a melt flow index (MFI) (@190°C / 21.6kg) of 25 g / 10 min according to ISO 1133-1, a hardness of 1.12 g / cm2 according to ISO 1183-1, and a hardness of 2.0 g / cm3 according to ISO 1183-1. 3 The 100µm layer contained processing additives: 2.5% diatomaceous earth and 0.3% amide wax. All ingredients of this first layer were processed in a single extruder.

[0073] The second layer is an ethylene vinyl acetate (EVA) copolymer grafted with maleic anhydride having an MFI (@230°C / 2.16 kg) of 3.5 g / 10 min according to ISO 1133-1 and an MFI (@230°C / 2.16 kg) of 0.94 g / cm according to ISO 1183-1. 3 The specific gravity is 28 mass %. The VA content of the resin is 28 mass %, and the maleic anhydride is less than 4000 ppm. The Shore A hardness according to ASTM D2240 is 80 / Shore D hardness is 27. The TMA starting temperature is 75°C. The second layer has a thickness of 50 μm.

[0074] The extrusion tool was set to a temperature of 160° C. to 200° C. The two melt streams were combined in a double-layer blown film die at a processing temperature of 195° C. and ejected through a circular die with a diameter of 130 mm. The circular melt was cooled by blowing cold air thereon. The film was then shrunk, laid flat, separated, and rolled up.

[0075] Example 2

[0076] The coextruded film was produced using a two-layer blown film die starting with a first layer formed from a thermoplastic polyurethane (TPU) ether having a Shore A hardness of 89 measured according to ASTM D2240, corresponding to a Shore D hardness of 36. The TPU ether had an MFI (@190°C / 21.6kg) of 25 g / 10 min according to ISO 1133-1 and a hardness of 1.12 g / cm2 according to ISO 1183-1. 3 The 90µm layer contained processing additives: 2.5% diatomaceous earth and 0.3% amide wax. All ingredients of this first layer were processed in a single extruder.

[0077] The second layer is a blend of 50 wt% TPU-ether with an MFI (@190°C / 21.6 kg) of 25 according to ISO 1133-1 and 1.12 g / cm2 according to ISO 1183-1 and 50 wt% of a graft copolymer of ethylene vinyl acetate / maleic anhydride. 3 The graft copolymer has a specific gravity of 89 Shore A hardness / 36 Shore D hardness according to ASTM D2240, and a TMA onset temperature of 165°C, and the graft copolymer has an MFI (@230°C / 2.16kg) of 3.5 g / 10 min according to ISO 1133-1 and a TMA onset temperature of 0.94 g / cm2 according to ISO 1183-1. 3 The specific gravity is 28 mass %. The VA content of the resin is 28 mass %, and the maleic anhydride is less than 4000 ppm. The Shore A hardness according to ASTM D2240 is 80 / Shore D hardness is 27. The TMA starting temperature is 75°C. The second layer has a thickness of 60 μm.

[0078] The extrusion tool was set to a temperature of 160° C. to 200° C. The two melt streams were combined in a double-layer blown film die at a processing temperature of 195° C. and ejected through a circular die with a diameter of 130 mm. The circular melt was cooled by blowing cold air thereon. The film was then shrunk, laid flat, separated, and rolled up.

[0079] Comparative Example 1

[0080] A single-layer blown film die was used to produce a film consisting of a thermoplastic polyurethane (TPU)-ether having a Shore A hardness of 89 measured according to ASTM D2240, corresponding to a Shore D hardness of 36. The TPU-ether had an MFI (@190°C / 21.6kg) of 25 g / 10 min according to ISO 1133-1 and an MFI (@190°C / 21.6kg) of 1.12 g / cm according to ISO 1183-1. 3The 150 µm layer contains processing additives: 2.5% diatomaceous earth and 0.3% amide wax. All components of this layer are processed in a single extruder.

[0081] The extruder was operated at a temperature of 160°C to 200°C. The melt stream was inserted into a blown film die at a processing temperature of 195°C and ejected through a lip set of 130 mm in diameter. The round melt was cooled by blowing cold air on it. The film was then shrunk, laid flat, separated, and rolled up.

[0082] Comparative Example 2

[0083] A coextruded film was produced using a two-layer blown film die, comprising a first layer formed of a thermoplastic polyurethane (TPU)-ester having a Shore A hardness of 90 measured according to ASTM D2240, equivalent to a Shore D hardness of 40. The TPU-ester had an MFI (@190°C / 21.6kg) of 60 g / 10 min according to ISO 1133-1 and a Shore D hardness of 1.22 g / cm2 according to ISO 1183-1. 3 The 30µm layer contains a processing additive of 5% diatomaceous earth and 1% amide wax. All components of this layer are processed in a single extruder.

[0084] The second layer is essentially made of linear hydroxyl polyester polyurethane. This flexible hot melt polyurethane with a high crystallization rate generally has excellent adhesion on a large number of materials. Extruded flat products made from this raw material are known to have a high quality. The TPU-ester has a viscosity of 1200 mPas according to ISO 3219 and a viscosity of 1.16 g / cm according to ISO 1183-1. 3 A specific gravity of 94 Shore A hardness / 45 Shore D hardness according to ASTM D2240 and a TMA onset temperature of 55° C. The second layer has a thickness of 20 μm.

[0085] The extrusion tool was set to a temperature of 130° C. to 180° C. The melt stream was introduced into a multilayer blown film die at a processing temperature of 180° C. and ejected through a round lip assembly having a diameter of 300 mm. The round melt was cooled by blowing cold air thereon. The film was then shrunk, laid flat, separated, and rolled up.

[0086] Comparative Example 3

[0087] A single-layer round blown film die was used to produce a film consisting of a 115 µm (4.5 mil) layer of low-density polyethylene (PE). The PE had an MFI (@190°C / 2.16 kg) of 0.4 g / 10 min according to ISO 1133-1, an MFI (@190°C / 2.16 kg) of 0.92 g / cm according to ISO 1183-1, and an MFI (@190°C / 2.16 kg) of 0.92 g / cm 3 and a Shore A hardness of 94 (equivalent to a Shore D hardness of 45) measured according to ASTM D2240. The PE has a TMA onset temperature of 103°C.

[0088] The extrusion tool is operated at a temperature of 160°C to 195°C. The melt stream is introduced into the blown film die at a processing temperature of 190°C and ejected through a lip assembly with a diameter of 130 mm. The round melt is cooled by blowing cold air on it. The film is then shrunk, laid flat, separated, and rolled up.

[0089] The evaluation and comparison of the performance of the samples according to the invention and the comparative samples focused on the adhesion to the barrier film.

[0090] The films prepared as examples and comparative examples were laminated using a HOTRONIX laminator. The films according to the examples and according to the comparative examples were laminated against a three-layer film EVA / PVDC / EVA with a thickness of 75 μm (3 mils). The lamination was carried out at 150° C. for 10 seconds.

[0091] A visual depiction of the artificial separation was determined, as well as tensile test results from the test rig.

[0092] For tensile testing, 1 inch / 25.4 mm wide specimen strips were cut from the laminate using a parallel blade specimen cutter. The separation force was determined using a conventional specimen grip and the load cell of the tensile testing apparatus.

[0093] To demonstrate bridging, a molded thermoplastic polyurethane (TPU) part was welded to a laminate film. Weld results and failure modes were compared when force was applied between the barrier film and the molded part.

[0094] In the following Table I, characteristic data of Examples and Comparative Examples are given.

[0095] Table I

[0096] nature Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 EVA layer facing EVA TPU / EVA blend layer facing EVA Hot melt adhesive polyurethane layer facing EVA Tensile Test - Description Film failure* - Very good adhesion Film failure* - Very good adhesion Adhesion failure Bond failure - very weak bond Membrane failure*) - Very good adhesion Tensile test-peel strength g / in. (gf) 1341 1014 123 4 1379 TPU parts welding success good good good good no Failure modes of structures No layer separation, barrier film failure No layer separation, barrier film failure Layer separation of TPU / barrier film Layer separation of TPU / barrier film Layer separation of TPU / laminated films

[0097] *Failed film: 3-layer barrier film EVA / PVDC / EVA at 3 mils.

[0098] These data clearly show that the membranes according to the invention are superior to the comparative membranes.

[0099] This specification has been written with reference to various non-limiting and non-exhaustive embodiments. However, it will be appreciated by those of ordinary skill in the art that various substitutions, modifications or combinations of any disclosed embodiment (or portion thereof) may be made within the scope of this specification. Therefore, it is conceivable and understood that this specification supports additional embodiments that are not explicitly set forth herein. Such embodiments may be obtained, for example, by combining, modifying or reorganizing the steps, components, elements, features, aspects, characteristics, limitations, etc. disclosed in the various non-limiting embodiments described in this specification. Thus, the applicant reserves the right to amend the claims during the examination to add the various described features in this specification, and such amendments comply with the requirements of 35 U.S.C. §112(a) and 35 USC §132(a).

[0100] Various aspects of the subject matter described herein are set forth in the numbered clauses below:

[0101] Clause 1. A barrier film comprising a first layer formed of a thermoplastic polyurethane (TPU) and a second layer formed of a heat activated olefin-based polymer coupling agent containing at least an ethylene-vinyl acetate (EVA) copolymer and a second polar comonomer, wherein the barrier film has a total thickness of 50 µm (2 mils) to 600 µm (24 mils), the first layer has a thickness of 20 µm (0.8 mils) to 400 µm (16 mils), and wherein the second layer has a thickness of 20 µm (0.8 mils) to 200 µm (8 mils).

[0102] Clause 2. The barrier film of Clause 1, wherein the ethylene vinyl acetate (EVA) copolymer contains at least 15% vinyl acetate.

[0103] Clause 3. The barrier film of Clause 1 or Clause 2, wherein the first layer has a Shore A hardness of 75-95 as measured according to ASTM D 2240.

[0104] Clause 4. The barrier film of any one of Clauses 1 to 3, wherein the second layer comprises a blend of thermoplastic polyurethane (TPU) and ethylene vinyl acetate (EVA) copolymer.

[0105] Clause 5. The barrier film according to any one of Clauses 1 to 4, wherein the ethylene vinyl acetate (EVA) copolymer comprises maleic anhydride in an amount less than 5000 ppm.

[0106] Clause 6. The barrier film according to any one of Clauses 1 to 5, wherein the second layer comprises a blend of thermoplastic polyurethane (TPU) and modified ethylene vinyl acetate (EVA) in a ratio of 0.3% to 3.0% by mass.

[0107] Clause 7. The barrier film according to any one of Clauses 1 to 6, wherein the second layer comprises a blend of thermoplastic polyurethane (TPU) and modified ethylene vinyl acetate (EVA) in a ratio of 0.7% to 1.5% by mass.

[0108] Clause 8. The barrier film according to any one of Clauses 1 to 7, wherein the second polar comonomer is selected from the group consisting of vinyl acetate, acrylic acid, acrylic acid esters, acrylic acid salts, methacrylic acid, methacrylic acid esters and methacrylic acid salts.

[0109] Clause 9. The barrier film according to any one of clauses 1 to 8, wherein 0% to 30% of an additive is added to the first layer, the additive being selected from anti-blocking agents, inorganic or organic release agents, slip aids or separation aids, pigments, fillers and stabilizers.

[0110] Clause 10. The barrier film according to any one of clauses 1 to 9, wherein the film is produced in a coextrusion process at a temperature of 160°C to 200°C.

[0111] Clause 11. The barrier film according to any one of clauses 1 to 9, wherein the film is produced in a blown film coextrusion process at a temperature of 160°C to 200°C.

[0112] Clause 12. The barrier film according to any one of clauses 1 to 11, wherein at least one layer is subjected to a physical or chemical surface treatment.

[0113] Clause 13. The barrier film of any one of Clauses 1 to 12, further comprising an adhesive layer applied to the first layer.

[0114] Clause 14. The barrier film of Clause 13, wherein the adhesive comprises polyurethane.

[0115] Clause 15. A laminate structure comprising the barrier film according to any one of Clauses 1 to 14 joined to an olefin base film.

[0116] Clause 16. The laminate structure of Clause 15, wherein the olefin is polyethylene.

[0117] Clause 17. The laminate structure according to any one of Clauses 15 and 16, wherein the barrier film and the olefin-based film are joined by a thermal bonding method selected from thermal lamination and flame bonding.

[0118] Clause 18. An open structure comprising the laminate structure according to any one of Clauses 15 and 17.

[0119] Clause 19. An ostomy bag comprising: a barrier film comprising a first layer formed of thermoplastic polyurethane (TPU) and a second layer formed of a thermoplastic polymer-based coupling agent containing an ethylene-vinyl acetate (EVA) copolymer and a second polar comonomer, wherein the barrier film has a total thickness of 50 µm (2 mils) to 600 µm (24 mils), wherein the first layer has a thickness of 20 µm (0.8 mils) to 400 µm (16 mils), and wherein the second layer has a thickness of 20 µm (0.8 mils) to 200 µm (8 mils); and an opening structure according to clause 17.

[0120] Clause 20. A method of performing a medical procedure selected from the group consisting of a colostomy, a urethrostomy, and an ileostomy, the method comprising comprising the ostomy bag of Clause 19.

[0121] Clause 21. An ostomy bag comprising: a barrier film comprising a first layer formed of thermoplastic polyurethane (TPU) and a second layer formed of a thermoplastic polymer-based coupling agent, the coupling agent comprising an ethylene-vinyl acetate (EVA) copolymer and a second polar olefin copolymer, wherein the barrier film has a total thickness of 50 µm (2 mils) to 600 µm (24 mils), wherein the first layer has a thickness of 20 µm (0.8 mils) to 400 µm (16 mils), and wherein the second layer has a thickness of 20 µm (0.8 mils) to 200 µm (8 mils); and an opening structure according to Clause 17.

[0122] Clause 22. A method of constructing an ostomy bag, the method comprising:

[0123] An olefinic film is joined with a barrier film to form a multilayer film, the barrier film comprising a first layer formed of a thermoplastic polyurethane (TPU) and a second layer formed of a thermoplastic polymer-based coupling agent containing an ethylene-vinyl acetate (EVA) copolymer and a second polar comonomer, wherein the barrier film has a total thickness of 50 µm (2 mils) to 600 µm (24 mils), wherein the first layer has a thickness of 20 µm (0.8 mils) to 400 µm (16 mils), and wherein the second layer has a thickness of 20 µm (0.8 mils) to 200 µm (8 mils), and a bag is formed, the bag comprising a first wall and a second wall joined together to define a closed compartment having an interior from the multilayer film.

Claims

1. A barrier film comprising: a first layer formed of thermoplastic polyurethane; and a second layer formed from a thermoplastic polymer-based coupling agent comprising ethylene-vinyl acetate copolymer and a second polar comonomer, wherein the barrier film has a total thickness of 50 μm to 600 μm, the first layer has a thickness of 20 μm to 400 μm, and the second layer has a thickness of 20 μm to 200 μm, wherein the ethylene-vinyl acetate copolymer contains at least 15% vinyl acetate, and wherein the first layer has a Shore A hardness of 75-95 measured according to ASTM D 2240, wherein the ethylene-vinyl acetate copolymer comprises maleic anhydride in an amount of greater than 0 and less than 5000 ppm, and wherein the second layer comprises a blend of thermoplastic polyurethane and modified ethylene-vinyl acetate in a ratio of 0.3% to 3.0% by mass. 2 . The barrier film according to claim 1 , wherein the second layer comprises a blend of thermoplastic polyurethane and modified ethylene vinyl acetate in a ratio of 0.7% to 1.5% by mass.

3. The barrier film of claim 1, wherein the second polar comonomer comprises a monomer selected from the group consisting of vinyl acetate, acrylic acid, acrylic acid esters, acrylic acid salts, methacrylic acid, methacrylic acid esters, and methacrylic acid salts.

4. The barrier film according to claim 1, wherein 0% to 30% of an additive is added to the first layer, and the additive is selected from an anti-blocking agent, an inorganic or organic release agent, a slip aid or a separation aid, a pigment, a filler and a stabilizer.

5. The barrier film according to claim 1, wherein the film is produced in a coextrusion process at a temperature of 160°C to 200°C.

6. The barrier film according to claim 5, wherein the film is produced in a blown film coextrusion process at a temperature of 160°C to 200°C.

7. The barrier film of claim 1, wherein at least one layer is subjected to a physical or chemical surface treatment.

8. The barrier film of claim 1, further comprising an adhesive layer applied to the first layer.

9. The barrier film of claim 8, wherein the adhesive comprises polyurethane.

10. A laminate structure comprising the barrier film of claim 1 joined to an olefin base film.

11. The laminate structure of claim 10, wherein the olefin is polyethylene.

12. The laminate structure of claim 10, wherein the barrier film and the olefin-based film are bonded by a thermal bonding method selected from the group consisting of thermal lamination and flame bonding.

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