Low-adsorption multilayer medical tubing

Abstract

To provide a flexible medical tube that has low absorption of drug solutions and their components. [Solution] The medical tube may have a continuous inner layer having a continuous outer layer thereon, the inner layer containing polyethylene, or polypropylene, or a polyolefin such as a functionalized polyolefin. The outer layer may contain a thermoplastic polymer such as one or more of thermoplastic polyurethane (TPU), thermoplastic olefin (TPO), thermoplastic elastomer (TPE), styrene-containing thermoplastic elastomer (S-TPE), polyolefin elastomer (POE), styrene-based block copolymer (SBC), or a blend containing these. Advantageously, the outer layer and / or inner layer do not contain polyvinyl chloride. Such tubes can be used as medical devices such as infusion sets.

Description

Technical Field

[0005] ,

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 111,538, filed on November 9, 2020, the entire disclosure of which is incorporated herein by reference.

[0002] The present disclosure generally relates to tubes, and particularly to flexible medical tubes with low absorption of drug solutions and their components. Such tubes can be used in medical devices such as tubes for the administration of drug solutions by intravenous drip.

Background Art

[0003] Plastic tubes are widely used in the medical field, particularly in patient analysis and treatment procedures. However, medical tubes are subject to various, sometimes incompatible requirements. For example, medical tubes should be strong but soft and flexible, resistant to twisting, less reactive with fluids, and not inject harmful chemicals into the fluid transported through the medical tube. However, many plastic materials with such properties tend to be inflexible. However, in many applications, medical tubes are used with infusion pumps that move fluid through the tube by pinching, clamping, or compressing the tube together. In such uses, a flexible, easily pinched, and quickly resilient tube is required. Soft tubes such as polyvinyl chloride using plasticizers have been used for many years in infusion sets. Unfortunately, plasticized polymer materials such as plasticized polyvinyl chloride may be sticky and can lead to tube blockage and rupture.

[0004] Therefore, there is a continuing need for medical tubes that can meet the various requirements of medical applications.

Summary of the Invention

[0005] Aspects of the subject art relate to a medical tube comprising a continuous inner layer having a continuous outer layer thereon. Advantageously, the inner layer comprises a polyolefin, and the outer layer comprises a polymer material different from the inner layer, such as a different thermoplastic polymer.

[0006] The polyolefin inner layer may include polyethylene, polypropylene, or functionalized polyolefin, or a combination thereof. The functionalized polyolefin may be selected from maleic anhydride-modified polyethylene, maleic anhydride-modified polypropylene, maleic anhydride-modified plastomer, amine-functionalized polyolefin, or a combination thereof. The outer layer may include thermoplastic polymers such as one or more of thermoplastic polyurethane (TPU), thermoplastic olefin (TPO), thermoplastic elastomer (TPE), styrene-containing thermoplastic elastomer (S-TPE), polyolefin elastomer (POE), styrene-based block copolymer (SBC), or blends thereof. Advantageously, the outer and / or inner layers are polyvinyl chloride-free.

[0007] The subject technology also relates to a method for manufacturing a medical tube by co-extruding a continuous inner layer having a continuous outer layer directly thereon, wherein the inner layer comprises a polyolefin and the outer layer comprises a thermoplastic polymer material different from that of the inner layer. The method may further include extruding a tie layer between the continuous inner layer and the continuous outer layer. The manufactured medical tube can be formed to transmit visible light.

[0008] The embodiments of the medical tubes and methods described above include one or more of the following features individually or in combination. In some embodiments, the medical tube may further comprise a tie layer between a continuous inner layer and a continuous outer layer. The tie layer may include maleic anhydride-modified polypropylene, maleic anhydride-modified polyethylene, ethyl vinyl acetate copolymer, or a combination thereof. Alternatively, the inner layer may be in direct contact with the outer layer. Furthermore, in other embodiments, the medical tube may comprise an intermittent, solvent-bondable segment layer in direct contact with the outer layer, such as an intermittent, solvent-bondable segment layer of thermoplastic polyurethane.

[0009] Further advantages of the subject art will be readily apparent to those skilled in the art from the detailed description below, and only specific aspects of the subject art are shown and described merely as examples. It should be understood that the subject art is capable of other different configurations, and some of its details can be modified in various other ways without departing entirely from the subject art. Therefore, the drawings and description should be considered illustrative and not limiting in nature.

[0010] The accompanying drawings are included for further understanding, are incorporated herein and constitute part of this specification, illustrate the disclosed embodiments, and together with the specification serve to illustrate the principles of the disclosed embodiments. [Brief explanation of the drawing]

[0011] [Figure 1] This figure shows an exemplary medical tube having a continuous inner layer and an outer layer according to an aspect of the present disclosure. [Figure 2] The present disclosure comprises another exemplary medical tube including a continuous inner layer, a continuous outer layer thereon, and a tie layer between the continuous inner layer and the continuous outer layer. [Figure 3] This figure shows another example of a two-layer polyolefin-lined medical tube. [Figure 4]This figure shows how specific variables affect the extrusion molding of medical tubing. [Figure 5] This figure shows the effect of adjusting specific variables during extrusion molding on adhesive strength. [Modes for carrying out the invention]

[0012] The detailed description below illustrates various configurations of the subject art and is not intended to represent only the configurations in which the subject art may be implemented. The detailed description includes specific details to provide a complete understanding of the subject art. Therefore, dimensions are provided for specific embodiments as non-limiting examples. However, it will be apparent to those skilled in the art that the subject art may be implemented without these specific details. In some cases, well-known structures and components are shown in block diagrams to avoid obscuring the concepts of the subject art.

[0013] It should be understood that this disclosure includes examples of the subject art and does not limit the scope of the appended claims. Various aspects of the subject art are disclosed below in accordance with specific but non-limiting examples. The various embodiments described herein may be carried out in different ways and variations according to the desired use or implementation.

[0014] The aspect of the subject technology relates to medical tubing that can adapt to various characteristic requirements. To overcome the technical challenges arising from conflicting design requirements for such tubing, medical tubing requires sophisticated material formulations and architectures. For example, medical tubing must be able to be coupled to fittings and other components for connecting tubing by solvent bonding, adhesive bonding, or mechanical bonding. Furthermore, medical tubing must not simultaneously absorb the drug solution and its components without altering the tubing itself or any active pharmaceutical ingredient (API). This requires both inert materials for drug compatibility and solvent-responsive materials for solvent bonding ability, which are typically conflicting requirements for a single material. Additionally, there is a movement towards more environmentally friendly materials and a movement to eliminate polyvinyl chloride (PVC). While the tubing is expected to recover quickly and completely, it also needs rigidity to allow for cutting processes for manufacturability.

[0015] The medical tubing of this disclosure can be used as medical tubing for intravenous administration of medications by infusion using intravenous assemblies for transporting intravenous fluids to a patient, gravity-feed containers, and / or infusion pumps. An assembly of tubing, valves, fittings, and needles that intravenously connects a fluid container to a patient is sometimes referred to as an "IV set." An infusion pump is a medical device that can be used to administer intravenous (IV) fluids. Such assemblies, containers, and pumps use tubing coupled to one or more medical connectors, and the tubing of this disclosure is useful on its own.

[0016] In some embodiments, the subject art relates to a medical tube comprising a continuous inner layer having a continuous outer layer thereon. Advantageously, the inner layer comprises a polyolefin having low absorption properties such that the polyolefin inner layer does not readily absorb the drug solution and / or components therein, or does not readily affect any active pharmaceutical ingredient (API) transported through the tube. Furthermore, the polyolefin inner layer is less susceptible to change in the tube itself due to the transport of the drug solution through the tube.

[0017] In some embodiments, the continuous inner layer may include functionalized polyolefins such as maleic anhydride-modified polyethylene (e.g., high-density polyethylene (HDPE) or low-density polyethylene (LDPE)), maleic anhydride-modified polypropylene, maleic anhydride-modified plastomer, or combinations thereof. Such functionalized polyolefins facilitate interlayer adhesion between the inner and outer layers.

[0018] The outer layer may contain a different polymer material from the inner layer so that the outer surface of the tube may have different properties from the inner layer material. For example, the outer layer may contain a thermoplastic polymer or a blend thereof, such as one or more of thermoplastic polyurethane (TPU), thermoplastic olefin (TPO), thermoplastic elastomer (TPE), styrene-containing thermoplastic elastomer (S-TPE), polyolefin elastomer (POE), styrene-based block copolymer (SBC), or a blend containing them. A thermoplastic polymer useful as an outer layer may be further blended with other polymer components and / or additives. For example, a thermoplastic polymer useful as an outer layer may be further blended with an adhesion promoter such as acrylic TPE, or a polar functionalized polyolefin such as up to 15 wt% or more of the blend, an adhesion imparterant, and a clarifying agent such as up to 10 wt% of the blend. Many thermoplastic polymers have properties that are advantageous for the outer layer of medical tubes, such as thermoplastic polyurethane (TPU), and these properties may be useful for solvent bonding the outer layer of the tube. Alternatively, or in combination, many thermoplastic polymers advantageously improve the flexibility of tubes.

[0019] In some embodiments of the medical tubes of this disclosure, the tie layer may be included between a continuous inner layer and a continuous outer layer.

[0020] Advantageously, the medical tubing of this disclosure is polyvinyl chloride-free. That is, the outer layer and / or inner layer and / or tie layer, if present, are polyvinyl chloride-free.

[0021] In some embodiments, the medical tubing of this disclosure may have a Shore A hardness greater than about 85 or less than about 85. A Shore A hardness greater than about 85 for medical tubing applications is typically considered rigid. Pump tubing typically uses softer tubing with a Shore A hardness of less than about 65, for example, 55 or less.

[0022] The following medical tube structure and material formulation can meet many of the requirements of IV sets and other requirements for medical tubes.

Table 1

[0023] As shown in Table 1, the continuous inner layer can include an amine-functionalized polyolefin or a maleic anhydride-modified polyolefin. Such an amine-functionalized polyolefin can be adjusted by reactive extrusion (for example, selection from 1, 2, 3, 4 in Table 1 above) by reacting a maleic anhydride-modified polyolefin with a polyetheramine in combination. This formulation or maleic anhydride-functionalized polyolefin can enhance the compatibility between the nonpolar, low surface energy material polyolefin and a group of more polar materials. The tube architecture of Table 1 requires good interlayer adhesion between the polar material group and the nonpolar material group, and thus this customization must enhance the adhesion of the inner layer to the outer layer.

[0024] The two-layer polyolefin-lined TPU medical tube structure as provided in Table 1 offers several advantages as follows. That is, the absence of a three-layer approach, an increase in processing line speed / line output compared to three layers. For example, the execution of coextrusion molding should be faster and less complex than three layers. The standard cost is expected to be lower than three layers, and due to compatibilization by functionalization of the inner layer compared to the weak adhesion of unmodified polyolefin, the layer adhesion is good, and as a result of the inner layer being a functionalized polyolefin, the drug adsorption is low.

[0025] Furthermore, in some embodiments, the continuous inner layer may be relatively thinner than the continuous outer layer, which should facilitate the tube having bulk properties similar to the TPU layer. Additionally, the ether-based TPU layer provides better solvent bonding, and the selection of an aliphatic main chain provides better color stability.

[0026] Figure 1 shows an example of a double-layer polyolefin-lined medical tube. Such a structure can be used with the polymer materials listed in Table 1 above to provide a solvent-bondable, low-adsorption double-layer polyolefin-lined TPU medical tube. As shown in the figure, the double-layer medical tube includes an inner layer (10) and an outer layer (12) immediately above the inner layer.

[0027] For use in applications including IV sets and / or infusion pumps, the tubing of the present disclosure may have an inner diameter for fluid flow in the range of about 1.5 mm to about 6 mm, for example, 2 mm to 4 mm. The overall sidewall thickness may be in the range of about 0.2 mm to about 1 mm, for example, 0.4 mm to 0.6 mm. In some embodiments of the present disclosure, the outer layer may include 10 to 90% of the sidewall thickness, and the inner layer may include 90 to 10% of the sidewall thickness. In one embodiment, the outer layer may have a thickness of about 0.01 mm to about 0.5 mm, for example, about 0.05 mm to about 0.2 mm, and the inner layer may have a thickness of about 0.1 mm to about 0.8 mm, for example, about 0.5 mm to about 0.5 mm.

[0028] Table 2 below shows another example of a medical tube structure that can be used in accordance with this disclosure. [Table 2]

[0029] As provided in Table 2, a medical tube may include a continuous inner layer, a continuous outer layer over the inner layer, and a tie layer between the continuous inner and outer layers. As provided in Table 2, the inner layer may include polyolefins such as polypropylene or polyethylene (e.g., linear low-density polyethylene (LDPE)). The outer layer may include thermoplastic polyurethane (TPU), which may be useful for solvent bonding the outer layer of the tube. The medical tube may also include a tie layer between the continuous inner and outer layers. Such a tie layer may include functionalized polyolefins such as maleic anhydride-modified polypropylene, maleic anhydride-modified polyethylene, or other tie layer polymers such as ethyl vinyl acetate copolymer (EVA), or a combination thereof.

[0030] The three-layer polyolefin-lined TPU medical tube structure, as shown in Table 2, offers several advantages. Specifically, compatibility is achieved without requiring more expensive functionalized polymers by selecting compatible main chains such as PP and PP-based TPO or POP, and PE and PE-based TPO or POE, and the inclusion of a PP or PE-based inner layer reduces drug adsorption.

[0031] Furthermore, in some embodiments, the continuous inner layer may be relatively thinner than the continuous outer layer, which should facilitate the tube having bulk properties similar to those of a TPU layer. In addition, the ether-based TPU layer provides better solvent bonding, and the selection of aliphatic backbone provides better color stability.

[0032] Figure 2 shows an example of a three-layer polyolefin-lined medical tube. Such a structure can be used with the polymer materials listed in Table 2 above to provide a solvent-bondable, low-adsorption polyolefin-lined TPU medical tube with a tie layer. As shown in the figure, the three-layer medical tube includes an inner layer (20), an outer layer (22), and a tie layer (24) that is in direct contact with the inner layer (20) and the outer layer (22).

[0033] For use in applications including IV sets and / or infusion pumps, the tubing of the present disclosure may have an inner diameter for fluid flow in the range of about 1.5 mm to about 6 mm, for example, 2 mm to 4 mm. The overall sidewall thickness may be in the range of about 0.2 mm to about 1 mm, for example, 0.4 mm to 0.6 mm. In some embodiments of the present disclosure, the outer layer may include 10 to 90% of the sidewall thickness, and the inner layer may include 90 to 10% of the sidewall thickness. In one embodiment, the outer layer may have a thickness of about 0.1 mm to about 0.8 mm, for example, about 0.5 mm to about 0.5 mm, and the inner layer may have a thickness of about 0.01 mm to about 0.5 mm, for example, about 0.05 mm to about 0.2 mm.

[0034] Figure 3 shows another example of a two-layer polyolefin-lined medical tube. Such a structure can be used to provide a solvent-bondable, low-adsorption polyolefin-lined medical tube. As shown, the medical tube comprises a continuous inner polyolefin layer (30) and a continuous outer layer (34). For this example, the medical tube further comprises an intermittent, solvent-bondable segmented layer (32) in direct contact with the outer layer 34. The intermittent, solvent-bondable segmented layer may include a thermoplastic polyurethane such as TPU, which has good bonding properties.

[0035] Table 3 below shows another example of a medical tube structure that can be used in accordance with this disclosure. [Table 3]

[0036] As provided in Table 3 above, medical tubing may include a continuous inner layer and a continuous outer layer immediately above it. The continuous inner layer may include non-functionalized polyolefins such as polyethylene (e.g., LDPE, HDPE) or polypropylene. The continuous outer layer may include thermoplastic polymers such as polyolefin elastomers (POE) (e.g., ethylene-octenopolyolefin elastomer, ethylene-butenopolyolefin elastomer), polyolefin plastomers (POP), propylene elastomers, and other thermoplastic polymers, or blends thereof.

[0037] Many thermoplastic polymers, including thermoplastic elastomers (TPEs) and thermoplastic olefins useful for the outer layer of medical tubes according to this disclosure, can be compounded with polyolefins for cost optimization, improved crystallinity, increased mechanical strength, increased working range (i.e., environmental stability and shelf life), and improved material compatibility (i.e., interlayer adhesion to the inner layer). The following are some different customizations that can overcome specific drawbacks of thermoplastic polymers from s-TPEs and TPOs.

[0038] Custom-made styrene-based block copolymer (SBC) compounds: SBC grades are useful due to their flexibility and solvent responsiveness, i.e., bonding properties. However, some of our experiments have shown that they have inferior kink resistance compared to other polymer types within styrene-based TPEs. Furthermore, certain SBC grades lack high-temperature resistance, as observed by their low softening points. Similarly, POP and POE grades, such as TPO from Engage Reactor, lack high-temperature resistance, as observed by their low softening points. Tables 4-5 provide examples of thermoplastic polymer blends that can be used as continuous outer layers for medical tubing according to this disclosure.

[0039] SBC blends with random PP copolymers: SBC blends with random PP copolymers produce solvent-bondable, kink-resistant materials for as-is tubing or for solvent-bondable lamination. Blend ratios can vary from 5 to 95% of olefin components (ethylene or propylene-based) additives, to be further refined based on transparency requirements. These blends may also contain adhesion promoters such as acrylic TPEs, or up to 15 wt% (of the blend) of polar functionalized polyolefins. Adding tackifiers, fining agents, and polymer processing aids up to 10 wt% (of the blend) is typical for these types of compounds when it is necessary to alter the melt, flow, rheology, and transparency of the tubing. Various processing variables can affect the transparency and mechanical properties of the tubing.

[0040] TPO blends with heat-resistant TPO such as random PP copolymers, polyolefins, or olefin-based block copolymers. The blend ratio can vary from 5 to 95% of the olefin component (ethylene or propylene-based), which can be adjusted based on transparency requirements. These blends may also contain adhesion promoters such as acrylic TPEs, or up to 15 wt% of polar functionalized polyolefins in the blend. It is typical for these types of compounds to add up to 10 wt% of tackifiers, fining agents, and polymer processing aids (of the blend) if it is necessary to change the melt, flow, rheology, and transparency of the tube. Various processing variables can affect the transparency and mechanical properties of the tube. [Table 4] [Table 5]

[0041] The medical tube structure of two-layer polyolefin-lined thermoplastic polymers, as provided in Table 3, offers several advantages, namely: the absence of a three-layer approach; increased processing cycle time compared to three layers; for example, co-extrusion molding should be faster and less complex than with three layers; costs are expected to be lower than with three layers; layer adhesion is good due to compatibility with the inner layer; and drug adsorption is low due to the inclusion of an unfunctionalized polyolefin inner layer.

[0042] The medical tubes of this disclosure can be manufactured by extrusion molding. For example, the medical tubes of this disclosure can be co-extruded as a continuous inner layer having a continuous outer layer thereon, wherein the inner layer comprises a polyolefin and the outer layer comprises a polymer material different from that of the inner layer. It is preferable to produce transparent medical tubes, for example, those that transmit visible light. There are a number of challenges in extruding transparent tubes. The following processing variables can result in differences between transparent and opaque tubes. Transparency is affected by die temperature, mold design, and parion ventilation.

[0043] Die Temperature: (a) Die temperature affects the transparency of the tube through its interaction with the tube's surface finish. Lowering the die temperature near the end of the die causes the outermost layer (surface) of the tube to "stick" to the mold as it is extruded. This sticking creates a difference in the polymer melting rate from the inside to the outside, resulting in micro-deformations (cracks) on the surface. These cracks give the tube an opaque or "matte" appearance. (b) Conversely, increasing the die temperature reduces the difference in polymer melting rate from the inside to the outside, making the tube more transparent and reducing the appearance of micro-deformations on the surface.

[0044] Mold Design: (a) Extrusion molds, as well as die temperature, can affect surface finish. By reducing friction between the mold material and the polymer molten material, the polymer melting rate becomes more consistent throughout the parison. This reduction in friction is achieved by applying a finishing or coating process to the mold.

[0045] Parison Aperture: (a) The last process parameter that can affect the clarity of the tube is the placement of the parison vents. The purpose of the vents is to ventilate any fumes from the parison as it is extruded, and they are usually placed just above the parison. Vents with large openings are placed far away from the parison and can capture any fumes, while small snake-type vents should be placed within a few centimeters (a few inches) of the parison. If the vents are placed too close to the parison, the parison will be affected by the air intake, which can alter the surface finish of the tube and result in an opaque / matte finish. (b) This is similar to the matte extrusion process, where cooling air is blown directly onto the parison as it is extruded.

[0046] Figure 4 shows how items 1 and 2 are affected during extrusion molding, and Figure 5 shows the effect of adjusting specific variables on adhesive strength during extrusion molding.

[0047] Any particular order or hierarchy of blocks in the disclosed process method is understood to be an example of an exemplary technique. It is understood that, based on design or implementation preferences, any particular order or hierarchy of blocks in the process can be rearranged, or that all illustrated blocks can be executed. In some implementations, any of the blocks may be executed concurrently.

[0048] This disclosure is provided to enable those skilled in the art to carry out various embodiments described herein. This disclosure provides various examples of the subject art, and the subject art is not limited to these examples. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments.

[0049] References to singular elements are intended to mean "one or more" rather than "one and just one" unless otherwise specified. Unless otherwise specified, the term "several" refers to one or more. Masculine pronouns (e.g., his) include feminine and neuter pronouns (e.g., her and her), and vice versa. Headings and subheadings, if any, are used for convenience only and do not limit the invention.

[0050] The term “exemplary” is used herein to mean “serving as an example or illustration.” No embodiment or design described herein as “exemplary” shall necessarily be construed as being preferable or advantageous to other embodiments or designs. In one embodiment, various alternative configurations and operations described herein may be considered at least equivalent.

[0051] As used herein, the expression “at least one of ~” preceding a list of items, along with the term “or” used to separate any of the items, modifies the entire list, rather than each individual item in the list. The expression “at least one of ~” does not require the selection of at least one item. Rather, it allows the meaning to include at least one of any of the items, and / or at least one of any combination of the items, and / or at least one of each of the items. For example, the expression “at least one of A, B, or C” can refer to A only, B only, or C only, or any combination of A, B, and C.

[0052] Expressions such as “Aspect” do not mean that such an aspect is essential to the subject art, or that such an aspect applies to all configurations of the subject art. Disclosure relating to one aspect may apply to all configurations, or to one or more configurations. An aspect may provide one or more examples. Expressions such as “Aspect” may refer to one or more aspects, and vice versa. Expressions such as “Example” do not mean that such an example is essential to the subject art, or that such an example can apply to all configurations of the subject art. Disclosure relating to one example may apply to all examples, or to one or more examples. An example may provide one or more examples. Expressions such as “Example” may refer to one or more examples, and vice versa. Expressions such as “Configuration” do not mean that such a configuration is essential to the subject art, or that such a configuration applies to all configurations of the subject art. Disclosure relating to a configuration may apply to all configurations, or to one or more configurations. A configuration may provide one or more examples. Expressions such as “Configuration” may refer to one or more configurations, and vice versa.

[0053] In one embodiment, unless otherwise specified, all measurements, values, grades, locations, sizes, dimensions, and other specifications described herein, including the following claims, are approximate and not exact. In one embodiment, they are intended to have a reasonable range that is consistent with the functions to which they relate and with what is customary in the art to which they relate.

[0054] It is understood that any particular sequence or hierarchy of steps, actions, or processes disclosed is an example of an exemplary method. It is understood that any particular sequence or hierarchy of steps, actions, or processes may be rearranged based on design preferences. Some of the steps, actions, or processes may be performed simultaneously. Some or all of the steps, actions, or processes may be performed automatically without user intervention. The claims of the attached methods present various elements of steps, actions, or processes in a sample sequence, if any, and are not meant to be limited to any particular sequence or hierarchy presented.

[0055] All structural and functional equivalents of elements of various aspects described throughout this disclosure, known or to those skilled in the art, are expressly incorporated herein by reference and intended to be encompassed by the claims. Furthermore, nothing disclosed herein is intended to be made available to the public, whether such disclosure is expressly stated in the claims or not. Unless an element is expressly stated using the expression “means for” or, in the case of a method claim, using the expression “steps for,” no element of the claims should be construed under Section 112(f) of the U.S. Patent Act. Furthermore, wherever terms such as “include” and “have” are used, such terms are intended to be inclusive in the same manner as the term “comprise,” as “comprise” is construed when used as a transitional word in the claims.

[0056] The title, background art, summary, brief description of the drawings, and abstract of this disclosure are incorporated into this disclosure and provided as exemplary examples of this disclosure, and not as limiting descriptions. They are presented with the understanding that they are not to be used to limit the scope or meaning of the claims. Furthermore, in the modes for carrying out the invention, it will be understood that exemplary examples are provided by description, and various features are grouped together in various embodiments for the purpose of streamlining this disclosure. The method of this disclosure should not be interpreted as reflecting an intention that the claimed subject matter requires more features than the features explicitly mentioned in each claim. Rather, as reflected in the following claims, the subject matter of the invention has fewer features than all the features of a single disclosed configuration or operation. Thus, the following claims are incorporated into the modes for carrying out the invention, and each claim stands alone as separately claimed subject matter.

[0057] The claims are not intended to be limited to the embodiments described herein, but are given the full scope consistent with the language of the claims and encompass all legal equivalents. Nevertheless, no claim shall, and should not be interpreted as, encompassing subject matter that does not meet the requirements of Section 101, 102, or 103 of the U.S. Patent Act.

Claims

1. A medical tube comprising a continuous inner layer having a continuous outer layer thereon, The inner layer is formed of a functionalized polyolefin, the outer layer comprises a thermoplastic polyurethane containing an adhesion promoter, and the outer layer is the outermost layer. The material of the inner layer is different from the material of the outer layer. The functionalized polyolefin includes an amine-functionalized polyolefin obtained by combining the functionalized polyolefin with one or more of the following: maleic anhydride-modified polyethylene, maleic anhydride-modified polypropylene, and maleic anhydride-modified plastomer. The aforementioned medical tube does not contain polyvinyl chloride. Medical tubing.

2. The medical tube according to claim 1, wherein the amine-functionalized polyolefin is formed by reacting a polyetheramine with a maleic anhydride-modified polyolefin.

3. The medical tube according to claim 1, wherein the thermoplastic polyurethane includes ether-based thermoplastic urethane.

4. The medical tube according to claim 1, wherein the thermoplastic polyurethane is a blend comprising one or more of an adhesion promoter and a clarifying agent.

5. The medical tube according to claim 1, wherein the outer layer comprises one or more of the following: thermoplastic olefin (TPO), thermoplastic elastomer (TPE), styrene-containing thermoplastic elastomer (S-TPE), polyolefin elastomer (POE), and styrene-based block copolymer (SBC), or a blend containing these.

6. The medical tube according to claim 5, further comprising a continuous second inner layer comprising polyethylene or polypropylene.

7. The medical tube according to any one of claims 1 to 6, wherein the inner layer is in direct contact with the outer layer.

8. The medical tube according to any one of claims 1 to 6, wherein the medical tube further comprises a second inner layer comprising polypropylene or polyethylene, and the functionalized polyolefin is a tie layer between the continuous second inner layer and the continuous outer layer.

9. The medical tube according to claim 8, wherein the second inner layer is linear low-density polyethylene (LDPE).

10. The medical tube according to any one of claims 1 to 6, wherein the medical tube has a Shore A hardness of 55 or less.

11. A medical tube according to any one of claims 1 to 6, further comprising an intermittent, solvent-bondable segment layer in direct contact with the outer layer, wherein the intermittent, solvent-bondable segment layer is included in only a portion of the length of the medical tube.

12. A method for manufacturing a medical tube according to claim 1, comprising co-extruding the continuous inner layer having the continuous outer layer thereon.

13. The method according to claim 12, wherein the medical tube transmits visible light.

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