Multi-layered tubing.

The present invention relates to polymeric pipe typically formed by a coextrusion process, the pipe that has multiple layers of the same or different polymeric materials, each layer successively adhered to each other.

Background of the Invention

The pipe comprised of polymeric material is used in many industrial and commercial applications including in the medical field. Several FDA-approved plastics are used (acronym for Food and Drug Administration) depending on the desired properties and the proposed applications. Where the pipe is for transporting fluids for the in vivo treatment of human patients, the selection of polymeric materials can be a factor.

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

Ref. 249920 doctor. Likewise, due to the inherent nature of plasticized PVC pipe, the potential absorption of medicines and other components of aqueous fluids used in medical treatments on the side wall of the PVC pipe increases. Polyurethane is potentially a substitute for PVC. However, the double-layer pipe comprised of polyurethane and polyethylene suffers from the inability of the two layers to remain attached to each other under conditions of mechanical manipulation or deformation or low or moderate tension. United States Patent No. 4,627,844 of Schmitt (Schmitt), the description of which is hereby incorporated by reference as if fully exposed, describes a three-layer tube that is incorporated into a commercial product sold under the SUREPATH 151 brand of Natvar Division of Tekni-Plex , Inc. How to

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fluid, with an intermediate tie layer of ethylene-vinyl acetate (EVA) copolymer. However, while Schmitt greatly reduces the possibility of migration of additives from the PVC into the fluid and the absorption of components from the fluid to the PVC pipe by providing an LDPE layer in contact with fluid, removal is preferred. PVC Other pipe configurations are described in U.S. Patent No. 7 \ 647,949, U.S. Patent No. 4,211,741 and U.S. Patent Publication No. 2007/0119511, descriptions of which are incorporated by reference as if they were fully disclosed herein.

Brief Description of the Invention In accordance with the invention, there is provided a tubular pipe, tube or device comprising at least three concentric layers of polymeric materials comprising an outer layer of a first selected polymeric material (typically comprised of at least about 90% by weight of a polyurethane), an inner layer of a second polymeric material selected (typically comprised of at least about 90% by weight of a polyethylene) and an intermediate layer of a third polymeric material (typically comprised of at least about 90% by weight of an acrylate-containing polymer ) which is placed between and joins the inner and outer layers together by adhesion mechanisms, such as chemical adhesion. The layers of polymeric materials are coextruded together to form the pipe such that the outer and inner layers adhere to the intermediate or middle layer and thus adhere to each other. The pipe is formed with a channel, hole or central passage, hollow that is

<img file="MX366202B_D0001.tif" />

'' i circled radially and defined by the polymeric layers that act as the pipe walls.

The polymeric materials are preferably free of contaminants meaning that they contain no more than significant amounts of potentially unwanted materials (typically less than about 0.5% and preferably less than about 0.2%, by weight) and / or prevent the leaching or leakage of materials. undesired such as plasticizers, catalysts, monomers, metals, salts, ions or other substances that are potentially unwanted to a human being in an aqueous medium or solution with which the other of the three layers can come into contact during the normal course of use of the pipe in the distribution of aqueous fluid, such as insulin , chemotherapy drugs and other drug suspensions, aqueous, potentially unstable, to or from a human subject. In addition to acting as an adhesive between and adhering to the outer and inner layers, the intermediate layer prevents delamination of the outer and inner layers of the intermediate layers under conditions of deformation or relatively low to moderate strain. In addition, the intermediate layer acts as a barrier to leaching or leaking contaminants from the outer layer to or through the inner layer into the hollow central hole or passages of the tube.

Preferably, the polymeric material in the outer layer is comprised of an elastomeric, thermoplastic (TPU) polyurethane material, the inner layer is comprised of a polyethylene (PE), typically a low density polyethylene ( LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE) or mixtures thereof, and the intermediate or middle layer is comprised of an ethylene-ethyl acrylate (EEA) copolymer, ethylene-methyl acrylate copolymer (EMA), an ethylene-acrylate-grafted ethylene-acrylate copolymer (AEMA), a copolymer of two or more of these acrylates or a mixture of two or more of the above.

With reference to Figures 1, 2, preferably the outer polyurethane layer 1 is between about 0.001 (0.00254 cm) and about 0.025 (0.0635 cm) thick, T3, the inner layer of polyethylene 3 is between about 0.001 (0.00254 cm) and approximately 0.025 (0.0635 cm) thick, TI, and the intermediate layer of acrylate copolymer 2 is between about 0.001 (0.0254 cm) and about 0.025 (0.0635 cm) thick, T2. Layers 1, 2, 3 collectively form a tubular wall that surrounds and defines a central passage 20 of fluid flow.

The ethylene-ethyl acrylate (EEA) copolymers, the ethylene-methyl acrylate (EMA) copolymers and the ethylene-acrylate-grafted methyl anhydride (AEMA) copolymers are elastomeric in nature and have excellent visual clarity. In a typical 3M3L coextrusion process, TPU, EEA or EMA or AEMA and PE are extruded in a molten state through a nozzle head to form a tubular extruded product that is then cooled through conventional water baths or Vacuum water tanks and subsequently either rolled or cut to a particular length for use. The level of elasticity and softness of the EEA, EMA AEMA or copolymers thereof is controlled by the amount of comonomer of methyl acrylate or ethyl acrylate used with ethylene in the copolymerization process. The resulting three layer tubes, elaborated by a coextrusion process they act in a monolithic way since they return to their original form and original dimensions after they are tensioned or stretched in a tense manner along the longitudinal axis of the tube at a tension of up to approximately 55 MPa and one of formation of up to approximately 900-950% and without any visual delamination between any of the layers after they are immersed in water at approximately 60 ° C for approximately 36 hours.

According to the invention, a tube is provided comprising an inner layer, an outer layer and a layer

<img file="MX366202B_D0002.tif" />

intermediate where the inner layer comprises a polyethylene, the outer layer comprises a thermoplastic polyurethane and the intermediate layer comprises an ethylene-acrylate copolymer or an ethylene-acrylate copolymer or an ethylene-acrylate copolymer grafted with anhydride , a copolymer of two or more of these acrylates a mixture of two or more of the above.

The inner layer typically comprises more than about 90% by weight of a polyethylene, the outer layer typically comprises more than about 90% by weight of an aromatic or aliphatic polyether-based polyurethane or the intermediate layer typically comprises more than about 90% by weight of an ethylene ethyl acrylate copolymer.

Typically, the polyethylene comprises one or more of a low density polyethylene, a linear low density polyethylene and a high density polyethylene, the aromatic polyether-based polyurethane typically comprises a polytetramethylene glycol-based polyurethane and the ethylene acrylate copolymer of Ethyl typically comprises at least about 19.5 percent by weight of ethyl acrylate content.

The inner layer typically comprises more than about 90% by weight of polyethylene, the outer layer typically comprises more than about 90% by weight of an aromatic polyether-based polyurethane and the intermediate layer typically comprises more than about 90% by weight of a copolymer of ethylene methyl acrylate.

The inner layer may comprise more than about 90% by weight low density polyethylene (LDPE) while the outer layer comprises more than about 90% by weight of a polyurethane based on polytetramethylene glycol and the intermediate layer comprises more than about 90% of an ethylene-acrylate copolymer grafted with anhydride.

Typically, the thickness of the outer layer of the polyurethane is between about 0.001 (0.00254 cm) and about 0.025 (0.0635 cm), the thickness of the inner layer of polyethylene is between about 0.001 (0.00254 cm) and about 0.025 (0.0635 cm) and The thickness of the acrylate copolymer intermediate layer is between about 0.001 (0.00254 cm) and about 0.025 (0.0635 cm).

More preferably, the inner and outer layers do not visually delaminate from each other at a tension of approximately 55 MPa and a deformation of up to approximately 900-950% when measuring a pipe length of approximately 2 inches (5.08 cm) of axial length at along its axis using a Lloyd LR5K plus mechanical tester at a rotation speed of approximately 12 inches (30.48 cmj / minute at ambient conditions of approximately 72 ° F (22.22 ° C) and approximately 50% humidity relative, the breaking point of the pipe 10 which is approximately 57-62 MPa and approximately 1000-1050-s.

More preferably, the tube does not visually delaminate after it is immersed in water at 60 ° C for 36 hours and subsequently flattened mechanically by manual crushing of the tube from its normal round cross-sectional condition to a condition or flattened or oval shape of cross section.

Preferably, the tube has an axial central passage of fluid flow through which aqueous fluid is routed, the inner layer having a radially inner wall surface that makes contact with the aqueous fluid, the outer and inner layers that resist delamination of each other at a tension of up to about 55 MPa and a deformation of up to about 900-950%.

In another aspect of the invention, a medical tube for transporting aqueous fluid is provided, comprising:

an inner layer comprising more than about 90% by weight of a polyethylene, an outer layer comprising more than 90% by weight of a polyurethane based on aromatic polyether, and an intermediate layer placed between the outer and inner layers comprising more than approximately 90% by weight of an ethylene-ethyl acrylate copolymer or an ethylene-methyl acrylate copolymer or an ethylene-acrylate-grafted copolymer with anhydride, a copolymer of two or more of these acrylates or a mixture of two or more of the foregoing.

In this embodiment, the inner and outer layers are not visually delaminated from one another preferably at a tension of up to about 55 MPa and a deformation of up to about 900-950%. And this tube is preferably not delaminated visually after it is immersed in water at 60 ° C for 36 hours.

In another aspect of the invention, a medical tube for transporting an aqueous fluid is provided, comprising:

an inner layer comprised of at least about 90% by weight of a polyethylene, an outer layer comprised of at least about 90% by weight of a polyurethane based on aromatic polyether, an intermediate layer placed between the inner and outer layers comprised of at least about 90% by weight of an ethylene-ethyl acrylate copolymer, an ethylene-acrylate copolymer, an ethylene-acrylate copolymer grafted with anhydride, a copolymer of two or more of these acrylates or a mixture of two or more of the above, wherein the pipe does not visually delaminate after it is immersed in water at 60 ° C for 36 hours.

In another aspect of the invention, a medical tube for transporting an aqueous fluid is provided comprising:

an inner layer comprised of at least about 90% by weight of a low density polyethylene, an outer layer comprised of at least about 90% by weight of a polyurethane based on polytetramethylene glycol, an intermediate layer comprised of at least about 90% by weight of an ethyl ethylene acrylate copolymer, an ethylene-acrylate copolymer, an ethylene-acrylate copolymer grafted with anhydride, a copolymer of these acrylates or a mixture of two or more of the above, where the pipe does not visually delaminate at a tension of up to about 55 MPa and a deformation of up to about 900-950%, and where the pipe does not visually delaminates after it is immersed in water at 60 ° C for 36 hours.

More preferably, the intermediate layer serves as a barrier against, or substantially prevents or substantially diminishes the migration of mobile portions such as monomers, short chain polymers, ions, water, small organic molecules, metals, plasticizers, catalysts and the like between outer and inner layers or the outer layer in the inner layer or the central flow passage or the central flow passage or inner layer in the outer layer.

Additionally, according to the invention there is provided a method for forming a medical tube 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 which has a selected structural stability; selecting a second polymeric material that is inert to aqueous fluids; , select a third polymeric material that easily bonds and adheres to the first and second polymeric materials of the co-extrusion and cooling of the materials;

co-extrude the first, second and third polymeric materials selected to form the medical tubing in a configuration such that the outer layer comprises at least about 90% by weight of the first polymeric material, the inner layer comprises at least about 90% by weight of the second polymeric material and the intermediate layer comprises at least about 90% by weight of the third polymeric material.

Preferably, in this method, the first polymeric material is selected to be a polyurethane, the second polymeric material is selected to be a polyethylene and the third polymeric material is selected from the group consisting of an ethylene-acrylate copolymer of ethyl, a copolymer of ethylene acrylate methyl, a copolymer of ethylene acrylate grafted with anhydride, a copolymer of these acrylate copolymers or a mixture of two or more of the above.

Additionally, according to the invention, there is provided a method for administering an aqueous fluid to a subject, which comprises;

selecting a tube comprising an inner layer, an outer layer and an intermediate layer, wherein the inner layer comprises a polyethylene, the outer layer comprises a thermoplastic polyurethane and the intermediate layer comprises an ethylene-methyl acrylate copolymer or a copolymer of ethylene-acrylate grafted with anhydride, a copolymer of two or more of these acrylates or a mixture of two or more of the foregoing;

wherein the tube has a central passage of fluid flow surrounded by the layers;

<img file="MX366202B_D0003.tif" />

route an aqueous fluid through the central fluid flow passage of the tubes, and administer the aqueous fluid routed through the central fluid flow passage to a subject's blood vessel.

In this method, the selection step preferably comprises:

co-extrude the outer, intermediate layers to form the tube such that the outer layer comprises at least about 90% by weight of the polyurethane, the inner layer comprises at least about 90% by weight of the polyurethane and the intermediate layer comprises at least about 90 % by weight of one or more of the acrylate copolymers.

Brief Description of the Figures

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

Fig. 1 is a schematic perspective view of a three layer tube showing the outer and intermediate or middle layers separated in order to better illustrate the arrangement of the pipe arrangement;

Fig. 2 is a cross-sectional view taken along lines 2-2 of tube 10 in Figure

1.

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Detailed description of the invention

An embodiment of a three-layer co-extruded pipe 10 according to the invention is shown in Figure 1 comprising an outer layer 1 comprised of at least about 90% by weight of a polyurethane material, typically a polyurethane-based polytetramethylene glycol , an example of which is Lubrizol TPU Pellethane 2363-90AE, an inner layer 3 in contact with fluid, comprised of at least about 90% by weight of a polyethylene material, typically a low density polyethylene, an example of which is Westlake LDPE JEM808AA and an intermediate bonding layer 2 comprised of at least about 90% by weight of an ethyl ethylene acrylate copolymer, an ethylene-acrylate copolymer, a copolymer of ethylene-methyl acrylate grafted with anhydride, a copolymer of two or more of these acrylates or a mixture of two or more of these acrylate-based compounds or compositions. An example of a suitable ethyl ethylene acrylate copolymer is Dow Amplify EA 103 (Ethylene Ethyl Acrylate which is approximately 19.5% by weight). Examples of suitable ethylene-acrylate copolymer are Westlake MA SP2268 (Methyl Ethylene-Acrylate which is approximately 24% by weight). Westlake MA SP2220 (Methyl Ethylene Acrylate which is approximately 20% by weight). An example of an ethylene acrylate copolymer of

<img file="MX366202B_D0005.tif" />

Methyl grafted with anhydride, suitable is Westlake Tymax GA 7001 (Ethylene-Methyl Acrylate Grafted with Anhydride).

As shown in Figure 1, the outer polyurethane layer 1 has a radially inner facing surface SI that joins and adheres to a radially outer facing surface S2 of the intermediate acrylate copolymer layer 2. Similarly, the inner layer of polyethylene material 3 has a radially outer facing surface S4 that joins and adheres to the radially inner facing surface S3 of the intermediate acrylate copolymer layer 2. The intermediate layer 2 adheres to the outer 1 and inner layers 3 such that the layers 1 and 3 remain adhered to the layer 2 and each other when the tube 10 is subjected to a tension of up to about 55 MPa and a deformation of up to about 900-950% as measured by pulling a section of pipe 10 of approximately 2 inches (5.08 cm) of axial length L along its A axis using a Lloyd LR5K Plus mechanical tester at a draft speed of approximately 12 inches ( 30.48 cm) / minute at ambient conditions of approximately 72 degrees F (22.2 ° C) and approximately 50% relative humidity, the breaking point of the pipe 10 which is at approximately 57-62 MPa and approximately 1000-1050%. Layers 1, 2, 3 of this pipe 10 do not visually delaminate after they are immersed in water at 60 ° C for 36 hours and

<img file="MX366202B_D0006.tif" />

subsequently they are mechanically flattened by manual crushing of the tube from its normal round condition in the cross section to a flattened or oval condition or shape in the cross section.

As shown in Figures 1 and 2, layers 1,

2, 3 are formed in structurally stable walls that surround and enclose a hollow central passage of fluid 20 through which an aqueous solution is routed and flows in an axial direction A that makes contact with the radially inner facing surface S5 of the layer interior 3. The intermediate layer 2 joins and holds together the inner and outer layers 1.

The inner layer 3 provides a radially inner surface S5 in contact with fluid, the thickness of the layer 3 which typically varies in the thickness of the cross section between approximately 0.001 inches (0.00254 cm) and approximately 0.025 inches (0.0635 cm). The intermediate layer 2 typically varies in thickness in cross section T2 of between about 0.001 (0.00254 cm) and about 0.025 inches (0.0635 cm). The outer layer 1 typically varies in thickness in cross section T3 of between about 0.001 inches (0.00254 cm) and about 0.025 inches (0.0635 cm).

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 Dow Chemical Company. The polyethylene material can also be a high density polyethylene (HDPE), such as Chevron 9506 HDPE, Chevron 9406 HDPE, and Chevron 9503 HDPE available from Chevron Corporation.

Polyurethane elastomer (TPU) is typically the reaction product of a polyol and isocyanate and usually includes a combination of hard and soft segment domains. An aromatic polyether based TPU or an aliphatic polyether based TPU can be used such as a polytetramethylene glycol based polyurethane. Preferred TPUs include the Pellethane 2363-80 AE series available from Lubrizol Corporation such as Lubrizol TPU Pellethane 236390AE.

The respective thickness of each layer of the pipe 10.20 can be controlled by the extrusion tool used, such as the Tri Pie extrusion apparatus manufactured by Genca Division of General Cable Company, Clearwater, Fia. The extrusion apparatus is selected to provide a uniform thickness of layers 1, 2, 3 along the substantial totality of the axial length L of the three layers 1, 2, 3.

The polymeric materials of which layers 1, 2, 3 are comprised are selected to be visually clear or transparent and manually flexible along and around the A axis of the pipe. Polymeric materials are also selected to maintain the integrity of the pipe 10 (specifically that delamination is not present) and its transparency or clarity after they are subjected to ethylene oxide (EtO) sterilization and gamma irradiation processes.

It is proposed that the foregoing description illustrates and does not limit the scope of the invention, those skilled in the art will understand that they are contemplated by the foregoing equivalent description thereof and that changes and modifications can be made without departing from the spirit of the invention. , all these equivalents, changes and modifications fall within the scope of the claims herein.

It is noted that in relation to this date, the best method known by the applicant to implement the present invention is that which is clear from the present description of the invention.