Radiopaque lined heat shrinkable tubing

Abstract

A non-limiting example of a radiopaque lined heat shrinkable tubing is a multi-layer construction having an inner layer and an outer layer, the inner layer comprising a thermoplastic resin highly filled with a radiopaque filler, and the outer layer comprising fluoropolymer heat shrink tubing.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of U.S. Provisional Patent Application No. 63,400,807, filed August 25, 2022, the disclosure of which is incorporated herein by reference in its entirety.

[0002] FIELD OF THE INVENTION FIELD OF THE INVENTION This application relates to heat shrink tubing and methods of making such heat shrink tubing, which have a variety of applications. [Background technology]

[0003] Heat-shrinkable tubing (also referred to herein as heat-shrink tubing) generally consists of a plastic material that is extruded and expanded into a tubular shape. The extruded and expanded tubing is designed to shrink (e.g., reduce in diameter) when heated to a predetermined temperature. As such, heat-shrink tubing can perform a variety of functions. It can provide a tight protective covering to closely encase and isolate various elements (e.g., to protect them from abrasion and provide thermal, chemical, moisture, and / or electrical isolation); it can bundle certain elements together (i.e., within the same heat-shrink tubing); it can isolate certain elements from other elements; it can be used to bond / fuse two elements, e.g., two tubes, together; and it can modify the properties of the underlying material (e.g., by closing around another material and shrinking that material as well). These capabilities make heat-shrink tubing useful for a variety of purposes, and it is used across a wide variety of industries, including the medical, chemical, electrical, optical, electronic, aerospace, automotive, and telecommunications sectors.

[0004] In medical environments, heat shrink tubing is particularly useful in designing increasingly smaller and more complex devices inserted into the body, including catheters, endoscopes, and the like. One typical medical application of heat shrink tubing involves the manufacture of guide catheters, which include a tubular structure having an inner layer of polymer, a middle layer of wire braid, and an outer layer of another polymer. To assemble such catheters, heat shrink tubing is typically applied to a shaft assembled around a mandrel, and the assembly is subjected to a temperature high enough to shrink the heat shrink tubing. Under these conditions, the outer polymer layer inside the catheter melts and flows, and the heat shrink tubing shrinks, providing a compressive force that allows the inner and outer polymer layers of the catheter shaft to bond together, encapsulating the wire braid inside. The heat shrink tubing can then be removed and discarded, and the catheter assembly can be removed from the mandrel. See, for example, U.S. Pat. No. 7,306,585 to Ross and U.S. Pat. No. 5,755,704 to Lunn, both of which are incorporated herein by reference.

[0005] Some medical devices include radiopaque markings to improve precision during medical procedures. Radiopaque markings are highly visible on x-rays. For example, the radiopaque markings create a sharp contrast that allows radiopaque features of the medical device to be visualized on x-rays to distinguish between radiopaque features of the medical device and non-radiopaque features of the medical device or the patient's body. Thus, medical personnel can use the sharp contrast caused by the radiopaque markings to assist in guiding the medical device through the patient's body.

[0006] Medical devices have been developed that utilize radiopaque markings applied to catheter shafts, such as marker bands applied to the outer layer of the catheter shaft. For example, conventional marker bands include short, thin-walled tubing machined from gold or platinum that is mechanically crimped or swaged at specific locations on the catheter. However, the use of such radiopaque markings has led to the radiopaque markings on the medical device becoming loose, shifting out of position along the medical device (e.g., catheter shaft), or becoming dislodged. These results can have adverse effects on the medical procedure, ranging from inaccurate positioning of the medical device to negative patient outcomes due to marker band dislodgment.

[0007] The present disclosure relates to tubing, and in particular to heat shrink tubing that includes a radiopaque component. Such heat shrink tubing is described herein in its expanded ("heat-shrunk") form and in its processed ("shrunk") form (e.g., as a component of a composition such as a catheter composition). Some multi-layer heat shrink tubing is also described herein as a means of introducing only one layer into a composition, e.g., one or more layers of processed heat shrink tubing are removed after placement of the desired layer.

[0008] The present disclosure includes, but is not limited to, the following embodiments. Embodiment 1: A tube comprising: an inner layer comprising a thermoplastic material, the thermoplastic material being filled with a radiopaque material; and an outer layer comprising a fluoropolymer material. Embodiment 2: The tube of embodiment 1, wherein the thermoplastic material comprises one or more of polyamide or Pebax (polyether block amide). Embodiment 3: The tube of embodiment 1 or 2, wherein the inner layer comprises radiopaque material in an amount of about 5% to about 80% by weight, based on the total weight of the inner layer. Embodiment 4: The tube of embodiment 1 or 2, wherein the inner layer comprises the radiopaque material in an amount of about 25% to about 50% by weight, based on the total weight of the inner layer. Embodiment 5: The tube of embodiment 1 or 2, wherein the inner layer comprises the radiopaque material in an amount of about 30% to about 40% by weight, based on the total weight of the inner layer. Embodiment 6: A tube described in any one of embodiments 1 to 5, wherein the radiopaque material is dispersed substantially uniformly throughout the inner layer. Embodiment 7: A tube according to any one of embodiments 1 to 6, wherein the outer layer is peelable. Embodiment 8: A tube described in any one of embodiments 1 to 7, wherein the radiopaque material comprises barium sulfate. Embodiment 9: A tube according to any one of embodiments 1 to 8, wherein the radiopaque material comprises one or more of bismuth oxychloride, bismuth basic carbonate, and tungsten metal powder. Embodiment 10: The tube of any of embodiments 1 to 9, wherein the inner layer has an average wall thickness of about 0.010 inches. Embodiment 11: The tube of any of embodiments 1 to 10, wherein the inner layer has an average wall thickness of between 0.005 inches and 0.020 inches. Embodiment 12: A tube according to any one of embodiments 1 to 11, wherein the fluoropolymer material of the outer layer comprises fluorinated ethylene propylene (FEP). Embodiment 13: A tube described in any of embodiments 1 to 11, wherein the fluoropolymer material of the outer layer comprises polytetrafluoroethylene (PTFE). Embodiment 14: A tube according to any one of embodiments 1 to 11, wherein the fluoropolymer material of the outer layer comprises perfluoroalkoxyalkane (PFA). Embodiment 15: A tube according to any one of embodiments 1 to 14, wherein the outer layer has a higher melting point than the inner layer. Embodiment 16: A tube described in any one of embodiments 1 to 14, wherein the inner and outer layers are in an expanded form. Embodiment 17: A tube described in any one of embodiments 1 to 16, wherein the ratio of the contraction of the expanded inner diameter of the tube to the recovered inner diameter of the tube is greater than 1.2:1. Embodiment 18: A medical device manufactured using the tubing of any of embodiments 1 to 17 (e.g., by positioning the tubing and applying heat and / or pressure to shrink the tubing into place). Embodiment 19: The medical device of embodiment 18, wherein the outer layer is removed (e.g., after the tube is in place and shrunk by application of heat and / or pressure). Embodiment 20: A medical device comprising a tube, the tube comprising a thermoplastic material filled with a radiopaque material. Embodiment 21: The medical device of embodiment 20, wherein the radiopaque material is dispersed substantially uniformly throughout the tube. Embodiment 22: A medical device comprising a tube according to any of embodiments 1 to 17 (in inflated or deflated form). Embodiment 23: A medical device comprising at least the inner layer of a tube according to any one of embodiments 1 to 17. Embodiment 24: The medical device of any of embodiments 18 to 23, wherein the medical device is a catheter. Embodiment 25: A medical device according to either embodiment 23 or 24, wherein the outer layer of the tube is removed during assembly of the medical device.

[0009] These and other features, aspects, and advantages of the present disclosure will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which are briefly described below. The present invention includes any combination of two, three, four, or more of the above-described embodiments, as well as any combination of two, three, four, or more features or elements described in this disclosure, whether or not such features or elements are explicitly combined in the description of a particular embodiment herein. The present disclosure, in all of its various aspects and embodiments, is intended to be read as a whole, such that all separable features or elements of the disclosed invention are intended to be combinable unless the context clearly indicates otherwise. Other aspects and advantages of the present invention will become apparent from the following.

[0010] For an understanding of embodiments of the present invention, reference is made to the accompanying drawings, which are not necessarily drawn to scale and in which reference numerals indicate components of exemplary embodiments of the present invention. The drawings are merely illustrative and should not be construed as limiting the invention. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a general schematic diagram of an arrangement 8 of the present disclosure. [Figure 2] FIG. 1 is a general schematic diagram of one method for forming a composition 8 of the present disclosure; and [Figure 3] 1 is a general schematic diagram of one way in which a composition 8 of the present disclosure may be placed / utilized, for example, within a medical device (other components not shown). DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all, embodiments of the invention are shown. Indeed, these inventions may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements.Like numbers refer to like elements throughout.

[0013] The present disclosure relates to heat-shrink tubing containing radiopaque fillers, as well as methods of making and using such tubing. The present disclosure further provides compositions, e.g., tubing containing two or more layers (in expanded and heat-shrunk forms). The present disclosure also provides methods of using these compositions, which in some embodiments can provide for the deployment and use of only one layer of the composition, e.g., by removing one or more layers of the composition after deployment. Thus, the present disclosure describes tubes / layers containing radiopaque fillers and their deployment / use within medical devices, such as catheter shafts.

[0014] In one embodiment, a construct 8 is provided that includes a first inner layer 10 and a second outer layer 12, as shown generally in Figure 1. The first inner layer 10 includes a thermoplastic material that includes one or more radiopaque materials. The second outer layer 12 includes a fluoropolymer material.

[0015] The first, inner layer 10 generally comprises a thermoplastic polymer. Thermoplastic polymers are known, and examples of suitable thermoplastic polymers include, but are not limited to, polyamide, Pebax (polyether block amide), urethane, polyethylene, or copolymers, derivatives, or combinations thereof. In some embodiments, layer 10 can consist essentially of a thermoplastic polymer and a radiopaque material.

[0016] The first inner layer 10 further comprises one or more radiopaque materials. Radiopaque materials are generally understood to be materials that are opaque to X-rays, such that devices or components thereof containing such materials are visible under fluoroscopy or radiography. In some embodiments, the radiopaque material is a high-density metal containing tungsten metal, such as tungsten metal powder. In some embodiments, the radiopaque material is a barium-containing compound (e.g., barium sulfate) or a bismuth-containing compound (e.g., bismuth oxychloride or bismuth basic carbonate).

[0017] The radiopaque material can be in the form of a solid material, such as, for example, a powder. Advantageously, the radiopaque material is generally uniformly dispersed throughout layer 10, although the disclosure is not so limited and layer 10, in some embodiments, can include clumps or clusters of radiopaque material. The amount of radiopaque material (i.e., loading) within a given layer 10 can vary and can be, for example, from about 5% to about 80% by weight based on the weight of layer 10, such as, for example, from about 5% to about 60% by weight, from about 5% to about 50% by weight, from about 25% to about 60% by weight, from about 25% to about 50% by weight, from about 30% to about 60% by weight, from about 30% to about 50% by weight, or from about 30% to about 40% by weight based on the weight of layer 10. Generally, but not exclusively, barium and bismuth based radiopaque materials can be incorporated at loadings towards the lower end of these ranges (e.g., about 30% to about 50% by weight), and tungsten can be incorporated at relatively higher loadings (e.g., up to about 80% by weight).

[0018] The first, inner layer 10 is generally tubular in shape, as shown in FIG. 1. In some embodiments, the wall is substantially uniform in thickness along the length of the tube and / or around the circumference of the tube. Layer 10 can have an average wall thickness of about 0.005 inches to about 0.020 inches, such as about 0.005 inches to about 0.015 inches, for example, about 0.010 inches. It is understood that the wall thickness and / or uniformity of layer 10 can vary in some embodiments depending on whether the layer is in the expanded (heat-shrunk) form or the used / shrunk form.

[0019] The second, outer layer 12, in some embodiments, comprises a fluoropolymer-based heat shrink tubing. The composition of the heat shrink tubing is not particularly limited. By way of example, the fluoropolymer may be fluorinated ethylene propylene (FEP), polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), or copolymers, mixtures, or derivatives thereof. Layer 11, in some embodiments, may consist essentially of one or more fluoropolymers.

[0020] In some embodiments, layer 12 comprises peelable tubing. Examples of peelable tubing and the manufacture of such tubing are described in U.S. Patent No. 10,434,222 to Roof et al., which is incorporated herein by reference in its entirety. "Peellable" means, for example, that layer 12 can be used to position layer 10 during the formation of a medical device, and can be easily removed from the construct, leaving layer 10 intact if desired, without becoming part of the final medical device in which it is incorporated. The composition of layer 12 can be selected to facilitate peelability. In some embodiments, this layer can include a blend with other materials to provide peelability. In some embodiments, in addition to the fluoropolymers described above, layer 12 can include up to about 30% by weight of fillers and / or additives to aid in peelability.

[0021] Like layer 10, layer 12 is also generally tubular in shape, and in some embodiments, the wall is substantially uniform in thickness along the length and / or circumference of the tube. The thickness of second, outer layer 12 is not particularly limited, and in some embodiments, layer 12 can have an average wall thickness of, for example, about 0.07 inches to about 0.020 inches. It is understood that the wall thickness and / or uniformity of layer 12 can vary in some embodiments depending on whether the layer is in the expanded (heat-shrunk) form or the used / shrunk form.

[0022] Advantageously, outer layer 12 can have a higher melting point than inner layer 10. These values ​​will necessarily vary depending on the exact composition of layers 10 and 12. As one non-limiting example, in some embodiments, layer 10 comprises 72D Pebax, which has a melting point of about 174°C, and layer 12 comprises FEP, which has a melting point of about 260°C.

[0023] The construct 8 can be tailored in sections, as shown in FIG. 2. The illustrated method includes, for example, expanding a tube to form expanded layer 12 (Step A), inserting tubing for inner layer 10 within the expanded outer tubing (Step B), and expanding the inner layer within the outer layer (Step C), e.g., so that the outer surface of inner layer 10 conforms to or contacts the inner surface of outer layer 12, as shown. Expansion can be accomplished by conventional methods, e.g., using heat and pressure, for example, to form a nested double-tube structure. The shrinkage ratio can be similarly varied. In some embodiments, the shrinkage ratio of the expanded inner diameter of the construct to the recovered inner diameter of the tubing is greater than 1.2:1.

[0024] In some embodiments, construct 8, including inner layer 10 and outer layer 12, is fabricated as a dual-layer heat shrink tubing. Examples of dual-layer heat shrink tubing and its fabrication are described in U.S. Patent Application Publication No. 2021 / 0370581, the entirety of which is incorporated herein by reference. Note that, while this disclosure refers to layers as "inner layer" and "outer layer," it is not intended to be limiting. For example, construct 8 can further include one or more additional layers, such as above layer 12 (thus layer 12 is not necessarily an "outer" layer of such construct). Similarly, construct 8 can further include one or more additional layers, such as below (inside) layer 10 (thus layer 10 is not necessarily an "inner" layer of such construct).

[0025] In various embodiments, the layer containing the radiopaque filler advantageously includes the radiopaque filler in the form of a material dispersed within the inner layer. The inner layer can ultimately be included as a component of (at least) the medical device (e.g., a catheter shaft). Such a composition provides the radiopaque marking as an integral component of the medical device (i.e., as an integral component incorporated within, for example, a layer of the catheter shaft). This configuration distinguishes such a composition from compositions in which the radiopaque label is simply affixed to the medical device or is otherwise associated with the medical device (e.g., as a conventional marker band). The disclosed composition ensures that the radiopaque marking will not migrate or become loose, for example, during placement or a medical procedure (because the radiopaque marking is dispersed throughout layer 10, which is an integral component of the medical device itself). Thus, in some embodiments, the disclosed tubes do not include any radiopaque components other than the radiopaque filler, i.e., any external radiopaque markings, e.g., any radiopaque markings (e.g., radiological marker bands) affixed to or otherwise associated with the tube.

[0026] Thus, in some embodiments, a medical device such as a catheter assembly (e.g., a catheter shaft) is provided that includes at least a tube containing a radiopaque filler, e.g., as described above with respect to layer 10 of the composition used to assemble the medical device. For example, the tube corresponding to layer 10 can be present as the innermost layer of the medical device, e.g., the innermost layer (inner diameter) of a catheter shaft. In other embodiments, the tube corresponding to layer 10 can be present around another tube (e.g., a catheter liner tube) that forms the innermost layer (inner diameter) of the catheter shaft. An example of a method for providing such a medical device component is shown in FIG. 3 , in which composition 8 is positioned / placed (e.g., around a mandrel or around another component, e.g., a tube / liner, etc., not shown); and heat and / or pressure are applied to the processed composition 8 (step D), which, in some embodiments, can result in shrinkage and / or reflow of outer layer 12 and / or inner layer 10. In some embodiments, as indicated by the dotted arrow in step E, outer layer 12 is optionally removed from the medical device during or after assembly (leaving only the reflowed inner layer 10 within the device). For example, the outer layer may be a peelable tubing that is removed after reflow of the inner layer 10. In other embodiments, outer layer 12 may be retained within the medical device (e.g., in a processed form, i.e., with the shrunk and / or reflowed components) such that the entire construct is a component of the medical device.

[0027] Many modifications and other embodiments of the invention will come to mind to one skilled in the art to which this invention pertains and having the benefit of the teachings presented in the foregoing description. It is to be understood, therefore, that the invention is not to be limited to the specific embodiments disclosed, and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. [Example]

[0028] Aspects of the present invention are more fully illustrated by the following examples, which are set forth to illustrate certain aspects of the invention and should not be construed as limiting the scope of the invention.

[0029] Example #1: Preparing nested pairs In the construction of this example, two charges were used. One was FEP heat shrink tubing with a minimum expanded inner diameter of 0.256 inches, a maximum recovered inner diameter of 0.166 inches, and a recovered wall thickness of 0.010 inches + / - 0.002 inches. The other charge was Pebax® tubing made from a compound containing Pebax® 5533 SA01 MED with 20% by weight loading of barium sulfate and a blue colorant. The Pebax® tubing had an inner diameter of 0.230 inches + / - 0.0025 inches and a wall thickness of 0.010 inches + / - 0.002 inches. One end of the Pebax® tubing was sealed and then slid inside the FEP heat shrink tubing so that a portion of the Pebax® tubing extended past each end of the FEP heat shrink tubing. The two-tube assembly was loaded into the vertical laminator with the open end of the Pebax® facing up and connected to the air supply system. Care was taken to connect only the Pebax® tube to the air supply system, not the FEP heat shrink tubing. The air supply system was opened and adjusted to supply 75 psi to the inside of the Pebax® tube. The vertical laminator was then started, and the heated nozzle was set to 275°F, traversing the sample at a speed of 2.5 mm / s. Once the cycle was complete, the part was removed from the vertical laminator and the ends were trimmed.

[0030] Example #2: Use of the nested pair of Example 1 in the construction of a catheter shaft An outer diameter etched PTFE liner with a 0.002-inch wall thickness was slid onto a tubular PTFE mandrel with a 0.222-inch outer diameter, and a 0.002-inch outer diameter SS wire braid was applied over the outer diameter etched PTFE liner. The part from Example 1 was then slid onto the braided liner. The assembly was then loaded into a vertical laminator. The vertical laminator was started, and the heated nozzle was set at 480°F, causing the sample to traverse at a speed of 1.2 mm / s. The part was then removed from the vertical laminator. The outer FEP portion of the part was then removed with a skiving tool, and the inner PTFE tubular mandrel was removed, resulting in a tube with an inner diameter PTFE-lined (lined) with Blue Pebax® 5533SA01 MED, an outer layer of 20% by weight barium sulfate, and an SS wire braid between the two layers.

Claims

1. an inner layer comprising a thermoplastic material, the thermoplastic material being filled with a radiopaque material; and an outer layer comprising a fluoropolymer material; Including the tube.

2. 10. The tube of claim 1, wherein the thermoplastic material comprises one or more of polyamide or Pebax (polyether block amide).

3. 10. The tube of claim 1, wherein the inner layer comprises the radiopaque material in an amount of about 5% to about 80% by weight, based on the total weight of the inner layer.

4. 10. The tube of claim 1, wherein the inner layer comprises the radiopaque material in an amount of about 25% to about 50% by weight, based on the total weight of the inner layer.

5. 10. The tube of claim 1, wherein the inner layer comprises the radiopaque material in an amount of about 30% to about 40% by weight, based on the total weight of the inner layer.

6. The tube of claim 1 , wherein the radiopaque material is dispersed substantially uniformly throughout the inner layer.

7. The tube of claim 1 , wherein the outer layer is peelable.

8. The tube of claim 1 , wherein the radiopaque material comprises barium sulfate.

9. 10. The tube of claim 1, wherein the radiopaque material comprises one or more of bismuth oxychloride, bismuth basic carbonate, and tungsten metal powder.

10. 10. The tubing of claim 1, wherein the inner layer has an average wall thickness of about 0.010 inches.

11. 10. The tubing of claim 1, wherein the inner layer has an average wall thickness of between 0.005 inches and 0.020 inches.

12. The tubing of claim 1 , wherein the fluoropolymer material of the outer layer comprises fluorinated ethylene propylene (FEP).

13. The tubing of claim 1 , wherein the fluoropolymer material of the outer layer comprises polytetrafluoroethylene (PTFE).

14. 10. The tubing of claim 1, wherein the fluoropolymer material of the outer layer comprises perfluoroalkoxyalkane (PFA).

15. The tubing of claim 1 , wherein the outer layer has a higher melting point than the inner layer.

16. 16. The tube of any one of claims 1 to 15, wherein the inner and outer layers are in an expanded form.

17. 2. The tubing of claim 1, wherein the ratio of the contraction of the expanded inner diameter of the tubing to the recovery inner diameter of the tubing is greater than 1.2:

1.

18. A medical device manufactured using the tube according to any one of claims 1 to 17.

19. 20. The medical device of claim 18, wherein the outer layer is removed.

20. A medical device comprising a tubing, the tubing comprising a thermoplastic material filled with a radiopaque material.

21. A medical device comprising a tube according to any one of claims 1 to 17.

22. A medical device comprising at least an inner layer of a tube according to any one of claims 1 to 17.

23. 23. The medical device of any one of claims 18 to 22, wherein the medical device is a catheter.

24. 24. The medical device of claim 23, wherein the outer layer of the tubing of claim 1 is removed during assembly of the medical device.

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