Multi-layered tubing

The present invention relates to a polymeric pipe typically produced by a co-extrusion process, wherein the pipe line has a plurality of layers of different polymeric substances.

Background [0002] Tubing consisting of a polymeric substance is used in many industrial and commercial applications, including in the medical field. Various FDA approved plastics are used, depending on the desired properties and intended uses. When tubing is used to transfer fluids for in vivo therapy of human patients or to deliver any fluid, which fluid or component contained in the fluid must be separated and maintained inside and not leaked through the pipe walls, an important factor may be the choice of polymeric substance having some selective property.

[0003] Poly (vinyl chloride) (PVC) is one of the most widely used plastics. Although it is structurally stable and easy to give it the desired shapes, PVC is typically made using plasticizers that can escape from the PVC matrix into body fluids and have other properties not well suited for use in medical therapy. Similarly, due to the intrinsic nature of plasticized PVC tubing, it is possible to absorb drugs and other components of aqueous fluids used in treatment heaps on the PVC pipe walls. In US Patent No. 4,627,844 to Schmitt ("Schmitt"), the disclosure of which is close to the object of the present invention, discloses a three-layer pipe that was commercialized under the trade mark "SUREPATH 151" by Natvar Division Tekni-Plex, Inc. As disclosed in Schmitt's publication, the PVC outer layer and the inner liquid-contact layer of low density polyethylene (LDPE) are co-extruded with an intermediate tie layer of an ethylene-vinyl acetate (EVA) copolymer. Polyurethane is a potential replacement for PVC, as disclosed in the jointly owned and the subject matter of the US documents, further numbers 13/354 029 and 13/586 288. Other tube configurations are disclosed in US Patent No. 7,647,949, US Patent No. 4,211,741 and US Patent No. 2007/0119511, the disclosures of which are close to the object of the present invention. Examples of the state of the art upon which the non-critical parts of the independent claims are based are given in The PVC outer layer and the inner liquid-in-contact layer of low density polyethylene (LDPE) are co-extruded with an intermediate tie layer of ethylene-vinyl acetate (EVA) copolymer. Polyurethane is a potential replacement for PVC, as disclosed in the jointly owned and the subject matter of the US documents, further numbers 13/354 029 and 13/586 288. Other tube configurations are disclosed in US Patent No. 7,647,949, US Patent No. 4,211,741 and US Patent No. 2007/0119511, the disclosures of which are close to the object of the present invention. Examples of the state of the art upon which the non-critical parts of the independent claims are based are given in The PVC outer layer and the inner liquid-in-contact layer of low density polyethylene (LDPE) are co-extruded with an intermediate tie layer of ethylene-vinyl acetate (EVA) copolymer. Polyurethane is a potential replacement for PVC, as disclosed in the jointly owned and the subject matter of the US documents, further numbers 13/354 029 and 13/586 288. Other tube configurations are disclosed in US Patent No. 7,647,949, US Patent No. 4,211,741 and US Patent No. 2007/0119511, the disclosures of which are close to the object of the present invention. Examples of the state of the art upon which the non-critical parts of the independent claims are based are given in as disclosed in the jointly owned and the subject matter of the US documents, reference numbers 13/354 029 and 13/586 288. Other tube configurations are disclosed in U.S. Patent No. 7,647,969, U.S. Patent No. 4,211,741, and U.S. Patent Publication No. 2007/0119511. the disclosures of which are close to the object of the present invention. Examples of the state of the art upon which the non-critical parts of the independent claims are based are given in as disclosed in the jointly owned and the subject matter of the US documents, reference numbers 13/354 029 and 13/586 288. Other tube configurations are disclosed in U.S. Patent No. 7,647,969, U.S. Patent No. 4,211,741, and U.S. Patent Publication No. 2007/0119511. the disclosures of which are close to the object of the present invention. Examples of the state of the art upon which the non-critical parts of the independent claims are based are given in

US2009286028 and US2009087606.

Summary of the invention [0004] According to the invention there is provided a pipe, pipe or pipe device that comprises at least three concentric layers of polymeric substances comprising an inner and outer layer of a polymeric substance composed of a thermoplastic polyurethane and a center layer composed of a polymeric substance comprising an acrylate-containing polymer, which is placed between the inner and outer layers and binds them due to adhesion mechanisms, such as chemical adhesion, without the need for additional binders or adhesive layers. The polyurethane, which consists of both inner and outer layers, may have the same or different structure, molecular weight, crystallinity, purity, content of monomeric units, degree of branching, chain length, additions content,

[0005] Layers of polymeric substances are co-extruded to form a conduit, so that the outer and inner layers adhere to the middle layer, and thus all three layers adhere to each other. The tubular conduit is formed so that it has a central hollow channel, aperture or passage, radially surrounded and bounded by polymeric layers that act as the wall or walls of the conduit.

[0006] The pipe or conduit is particularly suitable for transporting aqueous liquids such as liquids used in medical treatments and applications. Alternatively, a pipe or conduit may be used for directing, delivering and transporting non-aqueous and aqueous liquid and gas liquids, including organic substances such as ethers, alcohols, hydrocarbons, amines, aldehydes, ketones, amides, carboxylic acids and esters, and non-aqueous fluids such as oxygen, carbon dioxide, carbon monoxide, helium, neon, argon, krypton, xenon, radon, hydrogen, nitrogen and the like, and mixtures of two or more any of the above or one or more of the foregoing with aqueous liquid.

Preferably, the polymeric substance of the inner and outer layers consists of a polyurethane thermoplastic elastomeric material ("TPU") and the middle layer consists of a copolymer of ethylene with ethyl acrylate (EEA), an ethylene copolymer with methyl acrylate (EMA) grafted with copolymer anhydride ethylene with methyl acrylate (AEMA), a copolymer of two or more of the aforementioned acrylates or a mixture of two or more of the foregoing.

[0008] In one embodiment of the invention, the middle layer preferably has a thickness substantially greater than the combined thicknesses of the inner and outer layers. The thickness T2 in the cross-section of the central layer, figure 1, typically ranges from about 5% to about 98% and more often from about 10% and about 85% of the total thickness in the cross-section of the pipe wall 10 (namely the thickness T1 of the inner layer plus the thickness T2 the middle layer plus the thickness T3 of the outer layer). The thickness T2 of the middle layer can range from about 5% to about 30% of the total thickness in the cross section of the pipe wall, or in another embodiment about 31% to about 60%, and in yet another preferred embodiment of the invention from about 61% to about 98 %. By increasing the thickness of the middle layer in the pipe wall, that is, the proportional volume of the polymeric substance of the middle layer of the tube relative to the volume of the polymeric substance of the inner and outer layers, the cost can be significantly reduced and / or the other benefit (s) can be obtained. For example, when the polymeric layer of the middle layer is a soft ethylene-ethyl acrylate (EEA) and / or methyl ethylene-acrylate (EMA), these substances provide good adhesion to a polyurethane thermoplastic elastomer (TPU) and maintain resistance to pipe delamination under high load conditions and temperatures, but are less expensive than thermoplastic polyurethane elastomers that make up the inner and outer layers. Generally,

[0009] Thus, it can be imagined that in one embodiment of the invention the bulk of the side wall of the tube will be made of EEA or EMA substance and the inner layer and the TPU outer layer will be as thin as possible to still function both as a contact layer with fluid (inner layer) and as an outer layer with which various fittings (luer connectors, etc.) can be combined.

[0010] With reference to Fig. 1, 2, in one embodiment of the invention, the tube 10 with a length L extending along the longitudinal axis A of the pipe has polyurethane layers 3, 1, internal and external, which have a thickness T1, T3 from about 0, 00635 mm to about 0.635 mm (about 0.00025 to about 0.025 inches), and a middle layer 2 of a T2 acrylate copolymer from about 0.203 mm to about 3.048 mm (about 0.008 to about 0.120 inches). Layers 1, 2, 3 together form a tubular wall surrounding and defining a central passage 20 for fluid flow.

[0011] Ethylene-ethyl acrylate (EEA) copolymers, methyl-ethyl acrylate copolymers (EMA) and anhydride-grafted ethylene-methyl acrylate copolymers (AEMA) are elastomeric in nature and have excellent clarity. In a typical co-extrusion process, TPU and EEA or EMA or AEMA are extruded in the form melted through the die head to form a tubular shaped extrudate which is then cooled in conventional water baths or vacuum water tanks and which is in turn coiled or cut into a certain usable length. The level of elasticity and softness of the EEA, EMA AEMA or their copolymer is regulated by the amount of ethyl acrylate or methyl acrylate as the comonomer used with ethylene in the copolymerization process.

[0012] The polymeric substances are preferably "pollution-free", meaning that they contain no more than insignificant amounts of potentially undesirable substances (typically less than about 0.5% and preferably less than about 0.2% by weight) and / or prevented leaching or leaking unwanted substances such as plasticisers, catalysts, monomers, metals, salts, ions or other substances that are potentially undesirable to human beings, to an aqueous solution or other liquid medium with which one or other of the three layers may come into contact during the normal course of using a conduit for transferring an aqueous (or non-aqueous) fluid, such as insulin, chemotherapeutic drugs, and other potentially unstable aqueous drug suspensions, to or from a human subject. The middle layer prevents delamination of the layers: external and internal from the middle layer under relatively low to moderate strain or strain. In addition, the middle layer acts as a barrier against leaching or leaking of contaminants from the outer layer to or through the inner layer to the hollow central hole or channel of the tube.

[0013] According to one aspect of the invention, a tube is provided including an inner layer, an outer layer and a central layer, wherein the inner layer comprises thermoplastic polyurethane, the outer layer comprises a thermoplastic polyurethane and the middle layer comprises more than about

90% by weight of a copolymer of ethylene with ethyl acrylate or an ethylene copolymer with methyl acrylate or grafted with anhydride of an ethylene copolymer with methyl acrylate, a copolymer of two or more of said acrylates or a mixture of two or more thereof.

[0014] Each of the layers, inner and outer, preferably contains more than about 90% by weight of a polyurethane based on aromatic or aliphatic polyether.

[0015] One or both of the inner and outer layers may comprise polyurethane based on poly (tetramethylene glycol).

[0016] The ethylene methyl acrylate copolymer typically comprises at least about 19.5 percent by weight methyl acrylate.

[0017] The ethylene acrylate copolymer typically contains at least about 19.5 percent by weight ethyl acrylate. [0018] Furthermore, according to the invention, there is provided a method of manufacturing a fluid delivery pipe comprising; selecting a first substance containing more than about 90% by weight of a thermoplastic polyurethane, selecting a second substance comprising more than about 90% by weight of a thermoplastic polyurethane, selecting a third substance comprising more than about 90% by weight of a copolymer of ethylene with ethyl acrylate or a copolymer of ethylene with methyl acrylate or anhydride-grafted a copolymer of ethylene with methyl acrylate, a copolymer of two or more of the aforementioned acrylates or a mixture of two or more of the above, the production of a pipe composed of an inner layer of the first substance,

wherein the tube has a central channel for fluid flow surrounded by an inner, middle and outer layer. In such a method, the manufacturing step typically involves the co-extrusion of the first, second and third substances simultaneously to form the inner and outer layers having a cross section of from 0.00635 mm to 0.635 mm in thickness (about 0.00025 to 0.025 inches). ) and to form a central layer having a cross section of about 0.203 mm to about

3.048 mm (about 0.008 inch to about 0.120 inch).

[0020] The production step may comprise co-extrusion of the first, second and third substances so that the middle layer constitutes from about 5% to about 98% of the total thickness in cross-section of the combined inner, outer and middle layers.

[0021] The production step may comprise co-extrusion of the first, second and third substances so that the middle layer constitutes from about 10% to about 85% of the total thickness in cross-section of the combined inner, outer and middle layers.

[0022] The production step may comprise co-extrusion of the first, second and third substances so that the middle layer constitutes from about 61% to about 98% of the total thickness in cross-section of the combined inner, outer and middle layers.

[0023] In another aspect of the invention there is provided a method of providing an aqueous fluid to a subject comprising; selecting a tube comprising an inner layer, an outer layer and a central layer in which the inner and outer layers comprise more than about 90% by weight of one or more thermoplastic polyurethanes and the middle layer contains a copolymer of ethylene with ethyl acrylate or a copolymer of ethylene with methyl acrylate or anhydride-grafted copolymer ethylene with methyl acrylate, a copolymer of two or more of said acrylates or a mixture of two or more thereof; wherein the tube has a central channel for fluid flow surrounded by layers; transmission of the aqueous fluid through the central channel to the flow of the tube fluid, and supplying the aqueous fluid sent through the central channel to fluid flow into the subject's blood vessel. In such a method the selection step preferably involves co-extruding the outer, inner and middle layers to form a pipe, so that the intermediate layer contains at least about 90% by weight of one or more acrylate copolymers.

In another embodiment of the invention, such a method permits the transmission and delivery of liquid and gaseous non-aqueous liquids, including organic substances such as ethers, alcohols, hydrocarbons, amines, aldehydes, ketones, amides, carboxylic acids, esters and the like, and liquid substances. such as oxygen, carbon dioxide, carbon monoxide, helium, neon, argon, krypton, xenon, radon, hydrogen, nitrogen and the like, as well as mixtures of two or more all of the above with each one or mixtures of one or more of the foregoing; together with a water-based liquid. Most preferably, the inner, middle and outer layers of said pipes or pipes are not visibly detached from each other at a tension of up to about 55 MPa and a deformation to about 900950%, when measuring a tubing length of about 50, 8 mm (2 inches) in the axial direction along its axis using a Lloyd LR5K plus mechanical tester at a pulling speed of about 5 mm / s (12 inches per minute) at average ambient conditions of approximately 72 degrees F and approximately 50% relative humidity, disruption of the pipeline 10 occurs at about 57-62 MPa and about 1000-1050%. [0026] Most preferably, all said tubes or medical tubing are not visually delaminated after being immersed in water at 60 ° C for 36 hours and in turn mechanical flattening by manually squeezing the tube from its normal round state in cross-section to the shape or condition of the flattened or oval in cross-section.

Preferably, said tubes or medical tubing have a central axial fluid path through which the aqueous fluid is transmitted, the inner layer having an axially inner wall surface that contacts the aqueous fluid, the outer and inner layers resisting detachment from the middle layer at a tension of up to approximately 55 MPa and deformation to approximately 900-950%.

[0028] Most preferably, the middle layer serves as a barrier, prevents or substantially restricts the migration of motile compounds such as monomers, short chain polymers, ions, water, small organic molecules, metals, plasticizers, catalysts and the like between the outer and inner layers or from the outer layer to the inner or middle channel layer for the flow or from the central passage for the flow or the inner layer to the outer layer.

[0029] In another aspect of the invention there is provided a method of providing a non-aqueous fluid comprising; selecting a tube comprising an inner layer, an outer layer and a central layer, wherein the inner and outer layers comprise more than about 90% by weight of thermoplastic polyurethane and the middle layer contains more than about 90% by weight of a copolymer of ethylene with ethyl acrylate or an ethylene copolymer with methyl acrylate or graft an anhydride of a copolymer of ethylene with methyl acrylate, a copolymer of two or more of said acrylates or a mixture of two or more of the above; wherein the tube has a central channel for fluid flow surrounded by layers;

transmitting a non-aqueous fluid through the central channel to the fluid flow of the tube, and, providing a non-aqueous fluid channeled through the central channel to flow fluid to a previously selected fluid receiving warehouse.

In such a method, the fluid preferably comprises a liquid or non-aqueous liquid gas selected from the group of ethers, alcohols, hydrocarbons, amines, aldehydes, ketones, amides, carboxylic acids, esters, oxygen, carbon dioxide, carbon monoxide, helium, neon, argon, krypton, xenon, radon, hydrogen and nitrogen and mixtures of two or more of the foregoing with one another or one or more of the foregoing with an aqueous liquid.

[0031] The tube preferably does not visibly detach at a tension of up to about 55 MPa and a deformation to about 900-950%.

[0032] In all the embodiments and aspects of the invention described herein, the polyurethane polymer or substance from which the inner and outer layers are made separately may be the same or may have different structure, molecular weight, crystallinity, purity, monomeric unit content, branching degree, chain length, inorganic content and physical properties such as elongation, melting point, creep resistance and hardness.

Brief Description of the Drawings [0033] The drawings illustrate one or more aspects of the invention that are shown as examples of the invention in which:

Fig. 1 is a schematic perspective view of a three-layered pipe showing layers, outer and central, unfolded to better illustrate the structure and layout of the pipeline;

Fig. 2 is a cross-sectional view taken along the line 2-2 of the pipe 10 shown in Fig. 1.

Detailed description [0034] In FIG. 1 shows the form of a coextruded three-layer tubular 10 according to the invention, which comprises an outer layer 1 and an inner layer 3, each of which contains at least about 90% by weight polyurethane substance, typically poly (tetramethylene glycol), one example of which is Lubrizol TPU Pellethane 2363-90AE. The pipe or pipe 10 comprises a center layer 2 composed of a copolymer of ethylene with ethyl acrylate, a copolymer of ethylene with methyl acrylate, an anhydride grafted ethylene / methyl acrylate copolymer, a copolymer of two or more of said acrylates or a mixture of two or more of these acrylate-based compounds or of the composition. One example of a suitable ethylene / ethyl acrylate copolymer is Dow Amplify EA 103 (ethyl ethylene acrylate content of about 19.5% by weight). Examples of suitable ethylene / methyl acrylate copolymers are Westlake MA SP2268 (ethylene-acrylate methyl content about 24% by weight), Westlake MA SP2220 (ethylene-acrylate methyl content about 20% by weight). One example of a suitable ethylene / methyl acrylate grafted anhydride is Westlake Tymax GA 7001 (grafted with methyl ethyl acrylate anhydride).

[0035] As shown in Fig. 1, the outer layer of the polyurethane 1 has a radially inwardly facing surface S1 that bonds and adheres to the radially outward facing surface S2 of the middle layer 2 of the acrylate copolymer. Similarly, the inner layer 3 has a radially outwardly directed surface S4 that bonds and adheres to the radially inwardly facing surface S3 of the middle layer 2 of the acrylate copolymer. The middle layer 2 adheres to the outer and inner layers 3, such that the layers 1 and 3 remain adhered to the layer 2 and towards each other when the pipe 10 is subjected to a tension of up to about 55 MPa and a deformation of about 900-950% measured by stretching. pipeline 10 with a length of about 50, 8 mm (2 inches) in the axial direction of the length L along its A axis using a Lloyd LR5K Plus mechanical tester at a pulling speed of approximately 5 mm / s (12 inches per minute) at average ambient conditions of approximately 72 degrees F and approximately 50% relative humidity wherein the rupture of the pipeline 10 occurs at about 57-62 MPa and with a deformation of about 1000-1050%. Layers 1, 2, 3 of such tubular conduit 10 are not visibly delaminated after being immersed in water at 60 ° C for 36 hours and in turn mechanical flattening by manually compressing the tube from its normal round state in cross-section to the shape or condition of the flattened or oval in cross-section. wherein the rupture of the pipeline 10 occurs at about 57-62 MPa and with a deformation of about 1000-1050%. Layers 1, 2, 3 of such tubular conduit 10 are not visibly delaminated after being immersed in water at 60 ° C for 36 hours and in turn mechanical flattening by manually compressing the tube from its normal round state in cross-section to the shape or condition of the flattened or oval in cross-section. wherein the rupture of the pipeline 10 occurs at about 57-62 MPa and with a deformation of about 1000-1050%. Layers 1, 2, 3 of such tubular conduit 10 are not visibly delaminated after being immersed in water at 60 ° C for 36 hours and in turn mechanical flattening by manually compressing the tube from its normal round state in cross-section to the shape or condition of the flattened or oval in cross-section.

[0036] As shown in Figures 1 and 2, layers 1, 2, 3 are formed into structurally stable walls that surround and close the central hollow channel 20 for the fluid through which the fluid is transmitted and flows in the axial direction A by contacting radially facing the interior surface S5 of the inner layer 3. The middle layer 2 bonds and holds together the inner and outer layers 1 and 1.

[0037] The inner layer 3 provides a radially inner surface S5 in contact with the fluid, wherein the thickness T1 of the inner layer 3 typically varies in cross-section ranging from about 0.00635 mm to about 0.635 mm (about 0.00025 inches). to about 0.025 inches). The middle layer 2 has a thickness T2 in cross section of about 0.203 mm to about 3.048 mm (about 0.008 inch to about 0.120 inch). The thickness T3 of the outer layer 1 in cross-section typically ranges from about 0.00635 mm to about 0.635 mm (about 0.00025 inches to about 0.025 inches).

[0038] The polyurethane elastomer (TPU) is typically the reaction product of the polyol and isocyanate and usually comprises a combination of hard and soft segment domains. TPU based on aromatic polyether or TPU based on aliphatic polyether, such as polyethylene based on tetramethylene glycol, can be used. Preferably, TPU include the Pellethan 2363-80 AE series available from Lubrizol Corporation,

Wilmington, MA, like Lubrizol TPU Pellethan 2363-90AE.

[0039] A suitable thickness of each tubular layer 10,20 can be adjusted by the extrusion equipment used, such as the Tri Die extruder manufactured by Genca Division General Cable Company, Clearwater, Fla. The extruder is chosen so as to ensure uniform thickness of the layers 1, 2, 3 substantially over the entire axial length L of all three layers 1, 2, 3.

[0040] The polymeric substances of which the layers 1, 2, 3 are composed are selected so as to be visually clear or transparent and flexible manually along and about the axis A of the tubular conduit. The polymeric substances are also chosen to preserve the integrity of the pipeline 10 (namely, no delamination occurs), and transparency or clarity after exposure to ethylene oxide (EtO) and gamma irradiation.

[0041] The foregoing description is intended to illustrate and not limit the scope of the invention, it will be appreciated by those skilled in the art that changes and modifications may be made therein without departing from the invention, all such changes and modifications being within the scope of the present claims .

Tekni-Plex, Inc..

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