Polyurethane-polyethylene delamination resistant tubing with gas barrier properties.

SLIP RESISTANT PIPE OF POLYURETHANOL POLYETHYLENE WITH GAS BARRIER PROPERTIES

FIELD OF THE INVENTION

The present invention relates to a polymeric pipeline typically formed by a co-extrusion process, the pipeline having multiple layers of different polymeric materials, each layer successively adhered to each other.

BACKGROUND OF THE INVENTION

Tubing comprised of a polymeric material is used in many industrial and commercial applications, including in the medical field. Various FDA compliant plastics are used, depending on the desired properties and intended applications. When using tubing to transport fluids for in vivo treatment of human patients, the choice of polymeric materials may be a factor.

Polyvinyl chloride (PVC) is one of the most widely used plastics. While structurally stable and easily molded into desired shapes, PVC is typically manufactured using plasticizers that can migrate from the PVC matrix into body fluids and has other properties not ideally suited for applications.

Ref. 254330 of medical treatment. Also, due to the inherent nature of plasticized PVC pipe, potential absorption of medicines and other components of the aqueous fluids used in medical treatments arises in the side wall of the PVC pipe. Polyurethane is potentially a substitute for PVC. However, polyurethane and polyethylene comprised double layer pipe suffers from the inability of the two layers to adhere to each other under low to moderate stress, deformation or mechanical handling conditions, as well as the inability to sufficiently prevent oxygen migration through the layers. US Patent No. 4,627,844 by Schmitt (Schmitt), the disclosure of which refers to the related matter herein, describes a three-layer pipe that is modeled on a commercial product sold under the trademark SUREPATH 151 by Natvar Division of Tekni-Plex, Inc . As described in Schmitt, an outer layer of PVC and an inner layer of low-density polyethylene (LDPE) fluid contact are co-extruded with an intermediate bonding layer of acetate copolymer. ethylene vinyl (EVA). However, while Schmitt greatly reduces the possibility of migration of PVC additives to the fluid and absorption of fluid components into the PVC pipe, providing a contact layer with the

ΧΧΧΧΧΧ LDPE fluid, PVC removal is preferred. Other piping configurations are described in US Patent No. 7,647,949, US Patent No. 4,211,741, and US Patent Application No. 2007/0119511, the disclosures of which refer to the related subject matter herein. When a medical tubing is implicit, preserving the integrity of the reagents contained in the fluids that are routed through the tubing can be a problem. Similarly, preventing migration of components out of fluids through the pipeline may be a problem. In such applications, the incorporation into the pipeline of a layer of material comprised of a gas barrier material can be implemented for purposes of preventing the migration of gases, such as oxygen, into the fluid, thereby avoiding reagents sensitive to oxygen in the fluid.

BRIEF DESCRIPTION OF THE INVENTION

In accordance with the invention, there is provided a pipeline comprising an inner layer, an outer layer and a barrier layer device between the inner layer and the outer layer, where the barrier layer is joined to the outer layer by a layer of adhesive placed between the outer layer and the barrier layer, and the barrier layer is attached to the inner layer by an adhesive layer placed between

ΧΧΧΧΧΧ the inner layer and the barrier layer, where the inner layer comprises a polyethylene, the outer layer comprises a thermoplastic polyurethane and the barrier layer comprises a material that acts as a gas barrier.

The barrier layer preferably comprises more than about 90% by weight of an ethylene vinyl alcohol copolymer or a polyamide or mixtures thereof.

The adhesive typically comprises one or more acrylic copolymers of ethylene, more typically one or more copolymers of ethylene acrylate grafted with anhydride, and preferably one or more copolymers of ethylenemethyl acrylate grafted with anhydride.

The inner layer typically comprises more than about 90% by weight of a polyethylene and the outer layer comprises more than about 90% by weight of an aromatic or aliphatic polyether-based polyurethane.

The barrier layer typically comprises more than about 90% by weight of an ethylene vinyl alcohol copolymer or a polyamide or mixtures thereof, and the adhesive comprises more than about 90% by weight of one or more acrylic copolymers of ethylene.

The barrier layer may comprise more than about 90% by weight of an ethylene vinyl alcohol copolymer or a polyamide or mixtures thereof, and the inner layer may comprise more than about 90% by weight of a polyethylene and the outer layer may comprise more than about 90% by weight of an aromatic or aliphatic polyether-based polyurethane.

The adhesive may comprise more than about 90% by weight of one or more acrylic copolymers of ethylene and the inner layer may comprise more than 90% by weight of a polyethylene and the outer layer may comprise more than

<td colspan="2">approximately</td><td> 90%</td><td>in weigh</td><td>of</td><td>a polyurethane to</td><td colspan="2">base of</td>

<td>polyether</td><td>aromatic</td><td>ico o</td><td>aliphatic</td><td></td><td></td><td></td><td></td>

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<td colspan="2">approximately</td><td> 90%</td><td>in weigh</td><td>of</td><td>a copolymer of</td><td colspan="2">alcohol</td>

<td colspan="2">ethylene vinyl</td><td>Or uns.</td><td>polyamide</td><td>or</td><td colspan="2">mixtures thereof,</td><td>and the</td>

<td>adhesive</td><td>can</td><td colspan="2">understand more</td><td>of</td><td>about 90%</td><td>in</td><td>weight</td>

<td>one's</td><td>or more</td><td colspan="4">acrylic copolymers of ethylene,</td><td>1 a</td><td>cap</td>

<td>inside</td><td>can</td><td colspan="2">understand more</td><td>of</td><td>about 90%</td><td>in</td><td>weight</td>

of a polyethylene and the outer layer may comprise more than about 90% by weight of an aromatic or aliphatic polyether-based polyurethane.

The polyethylene typically comprises one or more of a low-density polyethylene, a linear low-density polyethylene and a high-density polyethylene, and the aromatic polyether-based polyurethane may comprise a polytetramethylene glycol-based polyurethane.

The adhesive may comprise more than about 90% by weight of one or more acrylic copolymers of ethylene, the inner layer may comprise more than about 90% by weight of low-density polyethylene (LDPE), the outer layer may comprise more than about 90 % by weight of a polytetramethylene glycol-based polyurethane and the middle layer may comprise more than about 90% by weight of a material that acts as a gas barrier.

The adhesive typically comprises more than about 90% by weight of one or more acrylic copolymers of ethylene.

The thickness of the polyurethane outer layer is typically between approximately 0.001 inch (0.0254 mm) and approximately 0.025 inch (0.635 mm), the thickness of the polyethylene inner layer is typically between approximately 0.001 inch (0.0254 mm) and approximately 0.025 inch ( 0.635 mm) and the thickness of the barrier layer is typically between about 0.001 inch (0.0254 mm) and about 0.025 inch (0.635 mm).

Preferably, the inner and outer layers do not visually delaminate when subjected to stress and deformation to the cadence point of the pipe, as measured by a mechanical tester and a pulling speed of approximately 12 inches per minute at ambient conditions of 72 ° F (22 ° C) and 50% relative humidity.

Preferably, the pipe is not visually delaminated when immersed in 60 ° C water for 36 hours.

Preferably, the pipe has a central axial fluid flow passage through which the aqueous fluid is directed, the inner layer having a radially inner wall surface that contacts the aqueous fluid, the outer and inner layers resisting delamination when stressed to the point of yield of the pipe, as measured in a mechanical tester at a traction speed of 12 inches per minute (5 mm / second) at ambient conditions of 72 ° F (22 ° C) and 50% relative humidity. Preferably, such a pipe is not visually delaminated after being immersed in 60 ° C water for 36 hours.

In such tubing, the thickness of the adhesive placed between the barrier layer and the outer layer is preferably between approximately 0.001 inch (0.0254 mm) and approximately 0.025 inch (0.635 mm) and the thickness of the adhesive placed between the barrier layer and the layer. Interior is preferably between approximately 0.001 inch (0.0254 mm) and approximately 0.025 inch (0.635 mm).

In another aspect of the invention, there is provided a medical tubing for the transportation of an aqueous fluid comprising:

an inner layer comprising more than about 90% by weight of a polyethylene, an outer layer comprising more than about 90% by weight of an aromatic polyether-based polyurethane,

<img file="MX369587B_D0001.tif" />

a barrier layer placed between the outer and inner layers comprising more than about 90% by weight of a material that acts as a gas barrier, and, an adhesive placed between the barrier layer and the outer layer and placed between the layer barrier and the inner layer, the adhesive comprising one or more acrylic ethylene copolymers.

In such an embodiment, the inner and outer layers do not preferably delaminate when subjected to stress and deformation to the point of pipe yield, as measured by a mechanical tester at a speed of

<td>traction of</td><td>12 inches</td><td>by</td><td>minute</td><td>(5 mm / i</td><td>second to</td>

<td>terms</td><td>environmental</td><td> 72°</td><td>F (22 ° C)</td><td>and 50%</td><td>moisture</td>

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preferably after soaking in water at 60 ° C for hours.

In such an embodiment, the adhesive comprises one or more anhydride-grafted ethylene acrylate copolymers.

In another aspect of the invention, there is provided a medical tubing for the transportation of an aqueous fluid comprising:

<td>A layer</td><td>inside</td><td>than</td><td>understands</td><td>by</td><td>least</td>

<td>approximately</td><td>90% by weight</td><td>of a</td><td>polyethylene</td><td></td><td></td>

<td>A layer</td><td>Exterior</td><td>than</td><td>understands</td><td>by</td><td>least</td>

about 90% by weight of an aromatic polyether-based polyurethane, a barrier layer placed between the outer and inner layers that comprises more than about 90% by weight of a material that acts as a gas barrier, and, an adhesive placed between the barrier layer and the outer layer and placed between the barrier layer and the inner layer, the adhesive comprising more than about 90% by weight of one or more acrylic ethylene copolymers, where the pipeline does not visually delaminate after being immersed in 60 ° C water for 36 hours.

In another aspect of the invention, there is provided a medical tubing for the transportation of an aqueous fluid comprising:

<td>a</td><td>cap</td><td>inside</td><td>than</td><td>understands</td><td>by</td><td>the</td><td>less</td>

<td colspan="2">approximately</td><td>90% in</td><td>weight</td><td colspan="2">of a polyethylene</td><td>of</td><td>low</td>

<td>density,</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>a</td><td>cap</td><td>Exterior</td><td>than</td><td>understands</td><td>by</td><td>the</td><td>less</td>

about 90% by weight of a polytetramethylene glycol-based polyurethane, a barrier layer placed between the outer and inner layers that comprises more than about 90% by weight of a material that acts as a gas barrier, and, an adhesive placed between the barrier layer and the outer layer and placed between the barrier layer and the inner layer, the adhesive comprising one or more acrylic ethylene copolymers, wherein the pipeline does not visually delaminate when subjected to stress and deformation to the pipeline yield point, measured on a mechanical tester at a pulling speed of approximately 12 inches per minute (5 mm / second) at ambient conditions 72 ° F (22 ° C) and 50% relative humidity, and, where the pipe does not visually delaminate after being immersed in water at 60 ° C for 36 hours.

In another aspect of the invention, there is provided a method of forming a medical tubing comprising an outer layer, an innermost layer, and an intermediate layer placed between the outer layer and the innermost layer, the method comprising:

selecting a first polymeric material that has a selected structural stability;

selecting a second polymeric material that is inert to aqueous fluids;

select a third polymeric material that acts as a gas barrier;

selecting a fourth polymeric material that easily binds and adheres to the first and second polymeric materials in co-extrusion and cooling of the materials;

co-extrude the first, second, third and fourth • IXSSSSS · selected polymeric materials to form the medical tubing in a configuration having an outer layer comprising at least about 90% by weight of the first polymeric material, an inner layer comprising at least about 90% by weight of the second polymeric material, a layer placed between the inner and outer layers comprising at least about 90% by weight of the third polymeric material, a layer of the fourth material placed between the outer layer and the layer of the third polymeric material and a layer of the fourth material placed between the inner layer and the layer of the third polymeric material.

In such a method, the first polymeric material is typically selected to be a polyurethane, the second polymeric material is selected to be a polyethylene, the third polymeric material is selected from the group consisting of a copolymer of ethylene vinyl alcohol and a polyamide, and the fourth material Polymeric is one or more acrylic copolymers of ethylene.

In such a method, the first polymeric material is preferably selected to be a polyurethane, the second polymeric material is selected to be a polyethylene, the third polymeric material is selected from the group consisting of an ethylene vinyl alcohol copolymer and a polyamide, and the fourth material Polymeric is selected so that the medical tubing is not visually delaminated after immersion in 60 ° C water for 36 hours.

In such a method, the adhesive typically comprises one or more anhydride-grafted ethylene acrylate copolymers.

In another aspect of the invention, there is provided a method for releasing an aqueous fluid to a patient, comprising:

select a pipeline comprising an inner layer, an outer layer and a barrier layer placed between the inner and outer layers, where the inner layer comprises a polyethylene, the outer layer comprises a thermoplastic polyurethane and the barrier layer comprises one or more of a copolymer of ethylene vinyl alcohol and a polyamide;

where the pipe has a central fluid flow passage surrounded by the layers;

directing an aqueous fluid through the central fluid flow passage of the tubing, and releasing the directed aqueous fluid through the central fluid flow passage into a patient's blood vessel.

The selection stage preferably comprises:

select the pipe so that a layer of an adhesive is placed between the outer layer and the barrier layer and between the inner layer and the barrier layer.

The selection stage typically comprises:

co-extrude the outer, inner, and barrier layers and the adhesive layers to form the pipe and select the adhesive to comprise more than about 90% by weight of one or more ethylene scrol copolymers.

Typically, the adhesive comprises one or more anhydride-grafted ethylene acrylate copolymers.

The adhesive may comprise one or more anhydride-grafted ethylenemethyl acrylate copolymers.

BRIEF DESCRIPTION OF THE FIGURES

The figures represent one or more embodiments of the invention shown by way of examples of the invention, wherein:

Figure 1 is a schematic perspective view of a five layer pipe showing the outer and middle or intermediate layers cut in order to better illustrate the construction and arrangement of the pipe;

Figure 2 is a cross sectional view taken along lines 2-2 of pipe 10 shown in Figure 1.

DETAILED DESCRIPTION OF THE INVENTION

Shown in Figure 1 is a five co-extruded layer 10, comprising an outer layer an embodiment of a pipe according to the invention, 1 comprised of at least about 90% by weight of a polyurethane material, typically a polytetramethylene glycol-based polyurethane, an example of which is Lubrizol TPU Pellethane 2363-90AE, an inner fluid contact layer 3 comprising at least about 90% by weight of a polyethylene material, typically a low-density polyethylene, an example of which is Westlake LDPE EM808AA, an intermediate gas barrier layer 5 comprising at least about 90% by weight of an ethylene vinyl alcohol (EVOH) copolymer, a polyamide, or a mixture of combination of two or more thereof and bonding layers 7, 9 comprised of an adhesive material that bonds the barrier layer 5 to the outer 1 and inner 3 layers. The gas barrier layer 5 acts as a barrier to gases, generally such as oxygen, nitrogen, hydrogen, chlorine, nitrous oxide, and the like. The adhesive layers 7, 9 preferably comprise a material that renders the pipe 10 subsequent to extrusion resistant to delamination, wherein the pipe does not visually delaminate after being immersed in water at 60 ° C for 3-6 hours and, subsequently, mechanically flatten by manually squeezing the pipe from its normal roundness in the cross-section condition to a flattened or oval cross-section shape or condition. The adhesive material is more preferably selected to comprise one or more acrylic ethylene copolymers, an example of which is an anhydride-grafted ethylenemethyl acrylate copolymer, a specific example of which is an anhydride-grafted ethylenemethyl acrylate copolymer, such as Westlake Tymax GA 7001 commercially available (anhydride grafted ethylenemethyl acrylate copolymer).

As shown in Figure 1, the polyurethane outer layer 1 has a radially inner face surface SI, which joins and adheres to a radically outer face surface S2 of the anhydride-modified acrylate adhesive layer 7. The layer Adhesive 7 has a radially inner face surface S3 which joins the radially outer face surface S4 of barrier layer 5. The barrier layer 5 has a radially inner face surface S5 that joins the surface of the radially outer face S6 of another layer 9 of adhesive. The adhesive layer 9 has a radially inner face surface S7 which joins the radially outer face surface S8 of the inner polyethylene layer 3. The intermediate barrier layer 5 adheres to the outer 1 and inner 3 layers, so that the three layers 1, 3 and 5 remain adhered to the layers 7, 9 and to each other when the pipe 10 is subjected to stress and deformation to the elastic yield point of the pipe, measured in a mechanical tester at a pulling speed of approximately 12 inches per minute (5 mm / second) at ambient conditions of 72 ° F (22 ° C) and 50% relative humidity . Mechanical testers for measuring such stress and strain are known in the art, an example of which is a Lloyd LR5K Plus mechanical tester. The elastic yield point is the highest point at which one or more of the pipe layers is permanently deformed, or as otherwise defined in Introduction to Physical Polymer Science, 4th .. Edition¹', LH Sperling (author), John Wiley &amp; Sons (publisher), 2006, the description of which is referred to in the related matter herein.

Layers 1, 3, 5, 7, 9 of such pipe 10 remain adhered to each other, so that the layers do not visually delaminate after being immersed in water at 60 ° C for 36 hours, and subsequently mechanically flattened by squeezing. manual the pipe from its normal roundness in the cross section condition to a flattened or oval cross section shape or condition.

As shown in Figures 1 and 2, layers 1, 3, 5 are formed on structurally stable walls that surround and enclose a central hollow fluid passageway 20 through which an aqueous solution is directed and flows in an axial direction A contacting the radially inner face surface S9 of the inner layer 3. The adhesive layers 7, 9 bond and hold the structural layers, the inner 3, inner 5 and outer 1 layers to each other.

Inner layer 3 provides a radially internal fluid contact surface S9, with the thickness of inner layer 3 typically ranging in thickness of cross section TI from about 0.001 inch (0.0254 mm) to about 0.025 inch (0.635 mm). Intermediate layer 5 typically ranges in thickness of cross section T3 from about 0.001 inch (0.0254 mm) to about 0.025 inch (0.635 mm). Outer layer 1 typically ranges in thickness of cross section T5 from about 0.001 inch (0.0254 mm) to about 0.025 inch (0.635 mm). Adhesive layers 7, 9 typically range in cross section thickness T2, T4 from about 0.001 inch (0.0254 mm) to about 0.025 inch (0.635 mm).

The polyethylene material is preferably a branched low-density polyethylene (LDPE), such as Westlake EM808, available from Westlake Chemical Corporation. The polyethylene material may be a linear low density polyethylene (LLDPE), such as Dowlex 2035G, available from the Dow Chemical Company. The polyethylene material can also be a high-density polyethylene (HDPE), such as Chevron 9506 HDPE, Chevron 94 06 HDPE, and Chevron 9503 HDPE, available from Chevron Corporation.

The polyethylene material can be a mixture or combination of two or more of the polyethylene materials mentioned above.

Polyurethane elastomer (TPU) is typically the reaction product of a polyol and an isocyanate and usually includes a combination of soft and hard segment domains. An aromatic polyether-based TPU or an aliphatic polyether-based TPU, such as a polyurethane based on polytetramethylene glycol, can be used. Such examples of these TPU's include the Pellethane 2363-90 AE series available from Lubrizol Corporation.

The respective thickness of each layer of pipe 10 can be controlled by the conventional multi-layer extrusion tool and equipment and typically includes a die holder configured to produce a multi-layer pipe, such as a five-layer pipe as shown in Figure 1. Such apparatus Extrusion extrusion is selected to provide a uniform thickness of layers 1, 3, 5, 7, 9 along the substantial totality of axial length L of all layers 1, 3, 5, 7, 9.

The polymeric materials of which layers 1, 3, 5, 7, 9 are comprised are preferably selected to be manually flexible along and around axis A of the pipe. Polymeric materials are also selected to maintain the integrity of pipe 10 (is

<img file="MX369587B_D0002.tif" />

say there is no delamination) and its transparency or

<td>clarity</td><td>then</td><td>of being</td><td>subdued</td><td>to processes</td><td>of</td>

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Limit the scope of the invention, those skilled in the art will realize that equivalents thereof are contemplated by the foregoing description and that changes and modifications may be made thereto without departing from the spirit of the invention, all such equivalents falling, changes and modifications within the scope of the present claims.

It is noted that in relation to this date, the best method known by the applicant to put the aforementioned invention into practice is the one that is clear from the present description of the invention.