Tie layer compositions and multilayer tubing incorporating same

Abstract

A PTFE-based liner having improved adhesion to a polymer jacket.SOLUTION: A multilayer tube comprising an inner layer and a tie layer is described. The inner layer comprises a fluorinated polymer and has an inner surface defining an inner diameter of the multi-layer tube and an outer surface separated from the inner surface by a thickness of the inner layer. The tie layer comprises a functionalized styrenic block copolymer and is disposed on an outer surface of the inner layer. When the multi-layer tube further comprises an outer layer, the multi-layer tube exhibits improved peel strength compared to a multi-layer tube comprising only an inner layer and an outer layer. Also described are methods of making the multi-layer tubes and articles comprising the multi-layer tubes.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure discloses a multilayer tube comprising an inner layer comprising a fluorinated polymer (e.g., polytetrafluoroethylene (PTFE)) and a tie layer comprising a functionalized styrenic block copolymer disposed on the outer surface of the inner layer. The multilayer tube comprising the fluorinated polymer layer, the tie layer, and the additional polymer layer can exhibit improved peel strength compared to the fluorinated polymer layer and the additional polymer layer alone. [Background technology]

[0002] (background) Polymeric tubing is used in many applications, such as intravascular medical devices. Various intravascular medical devices, including guidewires, catheters, and medical tubing, allow medical personnel to perform procedures such as the delivery of stents or other implantable devices. In some cases, implantable devices are inserted into a patient's vascular system at a convenient site and delivered through the vascular system to a target site. Coatings or liners on the inner walls of catheters or medical tubing are commonly used to provide a smooth inner surface. A smooth inner surface can reduce friction against an implantable device or other delivery component as it is pushed through the lumen of the catheter or medical tubing. One material widely used as a coating, tubing, or liner is polytetrafluoroethylene (PTFE).

[0003] PTFE has many beneficial properties, including chemical resistance, high-temperature resistance, biocompatibility, and a low coefficient of friction. In medical applications, the surface of PTFE tubing can be modified via an etching process to chemically activate the surface and increase adhesion strength to the outer jacket layer or other adjacent layers. However, the etching efficiency of PTFE liners can be affected by ultraviolet (UV) light, humidity, and storage time. To avoid efficiency loss, it is recommended to apply adjacent layers as soon as possible after the PTFE liner is manufactured, but lead times and other factors in the supply chain can make this difficult. As a result of the change in the coefficient of friction, adhesion between the PTFE liner and the tubing or jacket in which it is used may be less than desirable.

[0004] Consequently, a need exists for a PTFE-based liner that has improved adhesion to a polymer jacket. Summary of the Invention [Means for solving the problem]

[0005] (overview) This Summary is intended to provide some examples and is not intended to limit the scope of the present invention in any way. For example, any feature included in an example of this Summary is not required by a claim unless the claim explicitly recites that feature. Also, features, components, steps, concepts, etc. described in the examples of this Summary and elsewhere in this disclosure can be combined in various ways. Various features or steps described elsewhere in this disclosure may be included in the examples summarized herein.

[0006] The present disclosure discloses a multilayer tube comprising an inner layer comprising a fluorinated polymer (e.g., polytetrafluoroethylene (PTFE)) and a tie layer comprising a functionalized styrenic block copolymer disposed on the outer surface of the inner layer. The multilayer tube comprising the fluorinated polymer layer, the tie layer, and the additional polymer layer can exhibit improved peel strength compared to the fluorinated polymer layer and the additional polymer layer alone.

[0007] In one exemplary embodiment, the multi-layer tubing includes an inner layer comprising a fluorinated polymer, the inner layer having an inner surface defining an inner diameter of the multi-layer tubing, an outer surface spaced from the inner surface by the thickness of the inner layer, and a tie layer comprising a functionalized styrenic block copolymer disposed on the outer surface of the inner layer.

[0008] In another exemplary embodiment, a multi-layer tubing includes an inner layer comprising polytetrafluoroethylene (PTFE), the inner layer having an inner surface defining an inner diameter of the multi-layer tubing, an outer surface separated from the inner surface by (or by) the thickness of the inner layer, and a tie layer comprising a functionalized styrene block copolymer disposed on the outer surface of the inner layer.

[0009] In another exemplary embodiment, a method for making a multi-layer tube includes forming a tie layer on an outer surface of an inner layer comprising a fluorinated polymer from a tie layer coating composition comprising a functionalized styrenic block copolymer.

[0010] In another exemplary embodiment, an intravascular medical device includes a multi-layer tube of any other embodiment provided herein.

[0011] In another exemplary embodiment, the catheter comprises the multi-layered tubing of any other embodiment provided herein.

[0012] In another exemplary embodiment, the medical tubing comprises a multi-layer tubing of any other embodiment provided herein.

[0013] In embodiments, the functionalized styrenic block copolymer (or block copolymer) of any other embodiment provided herein comprises a maleic anhydride-grafted styrenic block copolymer. In embodiments, the functionalized styrenic block copolymer of any other embodiment provided herein comprises maleic anhydride-grafted poly(styrene-ethylene / butylene-styrene) (SEBS-g-MA). In embodiments, the functionalized styrenic block copolymer of any other embodiment provided herein comprises greater than 25 wt% styrene.

[0014] In some embodiments, the multilayer tubing of any other embodiment provided herein further includes an outer layer disposed on the tie layer such that the tie layer is disposed between the inner layer and the outer layer. In some embodiments, the outer layer of any other embodiment provided herein comprises polyurethane, polyamide, polyether, polyamide / polyether block copolymer, polyester, copolyester, stainless steel, glass, or a combination thereof. In some embodiments, the outer layer of any other embodiment provided herein comprises a polyamide / polyether block copolymer.

[0015] In embodiments, the tie layer of any other embodiment provided herein has a thickness of from about 2.5 μm to about 30 μm.

[0016] In some embodiments, the multilayer tube of any other embodiment provided herein further comprises a reinforcement layer. In some embodiments, the reinforcement layer of any other embodiment provided herein comprises a wire coil.

[0017] In embodiments, the outer surface of the inner layer of any other embodiment provided herein is etched.

[0018] In some embodiments, the multi-layer tubing of any other embodiment provided herein exhibits an increase in peel strength of at least about 25% compared to an otherwise identical multi-layer tubing that does not include a tie layer. In some embodiments, the multi-layer tubing of any other embodiment provided herein exhibits an increase in peel strength of about 25% to about 250% compared to an otherwise identical multi-layer tubing that does not include a tie layer.

[0019] In embodiments, the method of manufacturing the multi-layer tube of any other embodiment provided herein includes etching the outer surface of the inner layer prior to forming the tie layer.

[0020] In some embodiments, the method for manufacturing a multi-layer tubing of any other embodiment provided herein includes dipping the inner layer in a tie layer coating composition. In some embodiments, the method for manufacturing a multi-layer tubing of any other embodiment provided herein includes forming a reinforcing layer formed from a wire coil along at least a portion of the length of the multi-layer tubing. In some embodiments, forming the reinforcing layer of any other embodiment provided herein includes wrapping a wire around the tie layer. In some embodiments, the method for manufacturing a multi-layer tubing of any other embodiment provided herein includes forming an outer layer comprising polyurethane, polyamide, polyether, or a combination thereof on the tie layer such that the tie layer is disposed between the outer layer and the inner layer.

[0021] A further understanding of the nature and advantages of the present invention is set forth in the following description and claims, particularly when considered in conjunction with the accompanying drawings, in which like parts bear like reference numerals and in which:

[0022] BRIEF DESCRIPTION OF THE DRAWINGS To further clarify various aspects of the embodiments of the present disclosure, a more particular description of certain examples and embodiments will be provided with reference to various aspects of the accompanying drawings. It will be understood that these drawings depict only exemplary embodiments of the present disclosure and therefore should not be considered limiting of the scope of the present disclosure. Furthermore, while some examples may be drawn to scale, not all examples are necessarily drawn to scale. Examples and other features and advantages of the present disclosure will be described with additional specificity and detail through the use of the accompanying drawings. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is an axial cross-sectional view of a multi-layer tube according to one or more embodiments shown and described herein. [Figure 2] FIG. 2 is a bar graph showing the peel strength (Y-axis; in Newtons) of various samples (X-axis). [Figure 3] FIG. 3 is a bar graph showing the peel strength (Y-axis; units of Newtons) of PTFE Liner A and comparative samples incorporating a reinforcing layer as described in the Examples. [Figure 4] FIG. 4 is a bar graph showing the peel strength (Y-axis; units of Newtons) of samples without a reinforcing layer and containing the various PTFE liners, tie layers, and outer layers described in the examples. [Figure 5] FIG. 5 is a bar graph showing peel strength (Y-axis; units of Newtons) for samples incorporating PTFE liner B, a reinforcing layer, and a PEBAX outer layer as described in the Examples. DETAILED DESCRIPTION OF THE INVENTION

[0024] (Detailed explanation) The following description refers to the accompanying drawings that illustrate exemplary embodiments of the present disclosure. Other embodiments having different structure and operation do not depart from the scope of the present disclosure.

[0025] The present disclosure is directed to a tie layer comprising a functionalized styrenic block copolymer, a multilayer tubing comprising a tie layer and a fluoropolymer inner layer, a method for making the multilayer tubing comprising the tie layer, and an article comprising the multilayer tubing. The multilayer tubing comprising the fluoropolymer layer and an additional layer may exhibit improved peel strength compared to an otherwise identical multilayer tubing comprising only the additional polymer layer.

[0026] 1 shows an axial cross-section of an exemplary multi-layer tube 100. The multi-layer tube 100 includes an inner layer 102, a tie layer 104, and an outer layer 106. The tie layer 104 is disposed between the inner layer 102 and the outer layer 106. In the present disclosure, the multi-layer tube 100 may include the inner layer 102 and the tie layer 104. Consequently, it should be understood that the outer layer 106 is optional in some embodiments of the present disclosure. Additionally, other layers (e.g., a reinforcing layer, a fourth layer, a fifth layer, etc.) may be added in accordance with the present disclosure.

[0027] The multi-layer tube 100 extends axially along its length. The length of the multi-layer tube 100 can vary widely, for example, being 15 meters (m) or longer. The multi-layer tube 100 also includes an inner diameter ID defined by the inner surface of the inner layer 102. Similarly, the inner diameter ID can vary in some embodiments of the present disclosure. In some embodiments of the present disclosure, the inner diameter ID is suitable for use in catheter applications. The multi-layer tube 100 can have a generally cylindrical shape, although other shapes are possible.

[0028] Additionally, the inner layer 102 includes an outer surface that is spaced (or separated) from the inner surface by a thickness t1 of the inner layer 102. The wall thickness can generally be described as substantially uniform and does not vary appreciably around the circumference of the multi-layer tube 100 or along the length of the multi-layer tube 100.

[0029] In the present disclosure, the inner layer 102 typically comprises a fluorinated polymer such as polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), polyvinylidene fluoride (PVDF), or fluorinated ethylene-propylene copolymer (FEP). Fluorinated polymers (sometimes referred to herein as fluororesins) provide a low coefficient of friction on the inner surface of the multilayer tube 100 while exhibiting high thermal and chemical resistance. A variety of fluorinated polymer resins are commercially available and can be used to form the fluoropolymer tubes or liners provided herein. In various embodiments of the present disclosure, the inner layer 102 consists essentially of a fluorinated polymer, i.e., no additional components (e.g., fillers) are intentionally added to the inner layer 102.

[0030] As shown in FIG. 1 , the tie layer 104 is disposed on the outer surface of the inner layer 102. In other words, the tie layer 104 is concentrically outside the inner layer 102 of the multi-layer tube 100. In various embodiments of the present disclosure, the tie layer 104 is disposed directly on the outer surface of the inner layer 102, with no intervening layer between the tie layer 104 and the inner layer 102. The tie layer 104 has a thickness t2 separating a first surface of the tie layer 104 from a second surface of the tie layer 104. In various embodiments of the present disclosure, the thickness t2 of the tie layer 104 is from about 2.5 μm to about 30 μm, e.g., from about 2.5 μm to about 25 μm, or from about 3 μm to about 20 μm, including any and all ranges and subranges therein.

[0031] The tie layer 104 is generally formed from a composition (sometimes referred to herein as a "tie layer coating composition") that includes a functionalized styrenic block copolymer. In embodiments of the present disclosure, the functionalized styrenic block copolymer is a styrenic block copolymer having a grafting compound attached thereto. While various grafting compounds are known in the art, polar grafting compounds, more specifically maleated grafting compounds, are used in various embodiments of the present disclosure. In various embodiments of the present disclosure, the grafting compound is maleic anhydride. The amount of grafting compound in the functionalized styrenic block copolymer can vary depending on the particular embodiment, but in various embodiments of the present disclosure, the grafting compound is present in an amount greater than about 1 wt. % and less than about 5 wt. % based on the total weight of the functionalized styrenic block copolymer, for example, from about 1 wt. % to about 3 wt. %, including any and all ranges and subranges therein. In certain embodiments of the present disclosure, the functionalized styrenic block copolymer includes from about 1.4 wt. % to about 2 wt. % of the grafting compound based on the total weight of the functionalized styrenic block copolymer.

[0032] In the present disclosure, the styrenic block copolymer can have a linear structure, but in some embodiments, the styrenic block copolymer can also include a branched polymer, a radial polymer, or a functionalized block copolymer. In one or more embodiments, the styrenic block copolymer can include styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), styrene-ethylene / butylene-styrene (SEBS), styrene-ethylene-propylene-styrene (SEPS), or a combination thereof. In several embodiments of the present disclosure, the styrenic block copolymer is a styrenic block copolymer having 25 wt% or more styrene, for example, 30 wt% or more styrene, based on the total weight of the styrenic block copolymer. In some embodiments of the present disclosure, the styrenic block copolymer includes 25 wt% to 50 wt% styrene, or 30 wt% to 45 wt% styrene, including any range and subrange therein.

[0033] In certain embodiments of the present disclosure, the functionalized styrene block copolymer is maleic anhydride grafted SEBS (SEBS-g-MA). Various commercially available functionalized styrene block copolymers may be suitable for use in the tie layer, including, but not limited to, KRATON FG1901G polymer, a 30% polystyrene content linear triblock copolymer based on styrene and ethylene / butylene functionalized with 1.0 wt% to 2.0 wt% maleic anhydride (e.g., 1.0 wt% to 2.0 wt%, 1.4 wt% to 2.0 wt%, 1.0 wt% to 1.7 wt%, or 1.4 wt% to 1.7 wt%) available from Kraton Corporation (Houston, Texas); or KRATON 13% polystyrene content linear triblock copolymer based on styrene and ethylene / butylene functionalized with 0.7 wt% to 1.3 wt% maleic anhydride (e.g., 0.7 wt% to 1.3 wt%, 1.0 wt% to 1.3 wt%, 0.7 wt% to 1.2 wt%, or 1.0 wt% to 1.2 wt%) available from Kraton Corporation (Houston, Texas). Contains FG1924G polymer.

[0034] In various embodiments of the present disclosure, the composition forming tie layer 104 (i.e., the tie layer coating composition) consists essentially of the functionalized styrenic block copolymer, i.e., no additional components (e.g., fillers) are intentionally added to the composition forming tie layer 104. In certain embodiments of the present disclosure, the composition forming tie layer 104 consists essentially of SEBS-g-MA. In various embodiments of the present disclosure, the composition forming tie layer 104 consists of the functionalized styrenic block copolymer, i.e., no additional components (e.g., fillers) are present in the composition forming tie layer 104. In certain embodiments of the present disclosure, the composition forming tie layer 104 consists of SEBS-g-MA. In various embodiments of the present disclosure, the composition forming tie layer 104 excludes a tackifier (or tackifier). In various embodiments of the present disclosure, the composition forming tie layer 104 excludes a non-SEBS tackifier. In certain embodiments, the composition forming tie layer 104 excludes a non-SEBS-g-MA tackifier or tackifier in addition to SEBS or SEBS-g-MA. In various embodiments of the present disclosure, the composition forming the tie layer 104 excludes ethylene / alpha olefin copolymers. In embodiments of the present disclosure, the composition forming the tie layer 104 excludes tackifiers and ethylene / alpha olefin copolymers.

[0035] Without being bound by theory, it is believed that in addition to improving adhesion between the inner and outer layers, the tie layer protects the inner layer against the adverse effects of UV light and / or moisture, thereby allowing the inner layer to have a longer shelf life.

[0036] 1 , the multi-layer tube 100 further includes an optional outer layer 106. The outer layer 106 may be referred to as a "jacket" and may be added to the multi-layer tube 100 to impart different physical properties to the multi-layer tube 100. For example, the outer layer 106 may impart strength and stiffness to the multi-layer tube 100. The outer layer 106 may have any suitable thickness and, if included, may extend along all or a portion of the length of the multi-layer tube 100. In embodiments of the present disclosure, the outer layer 106 is configured with one or more segments of different lengths and hardnesses, which may be used to impart different properties to different longitudinal sections of the multi-layer tube 100.

[0037] The outer layer 106 may comprise any material known and used in the art. In embodiments of the present disclosure, the outer layer 106 comprises stainless steel, glass, a polymer, or a combination or derivative thereof. The polymer included in the outer layer 106 may include, by way of example and not limitation, polyurethane, polyamide, polyether, low-density polyethylene (LDPE), high-density polyethylene (HDPE), polyethylene terephthalate (PET), polyamide / polyether block copolymer, polyester, copolyester, or a combination or derivative thereof, including, but not limited to, polyamide / polyether block copolymer. Commercially available materials suitable for use include, by way of example and not limitation, products available under the trademarks TECOFLEX (an aliphatic polyether-based thermoplastic polyurethane available from The Lubrizol Corporation, Wickliffe, Ohio), PEBAX (a polyether block amide available from Arkema SA, France), and VESTAMID (a polyamide 12 available from Evonik Industries AG, Germany).

[0038] In embodiments of the present disclosure, outer layer 106 consists essentially of polyurethane, polyamide, polyether, or combinations thereof, i.e., no additional components (e.g., fillers) are intentionally added to outer layer 106. However, in some embodiments, outer layer 106 includes one or more additives, including, but not limited to, radiopaque fillers or radiopaque nanoclays, which are known and usable in the art. Radiopaque fillers include, without limitation, barium sulfate, bismuth subcarbonate, bismuth trioxide, bismuth oxychloride, tungsten, tantalum, platinum, gold, and combinations thereof.

[0039] Although referred to herein as an "outer layer," it is contemplated that one or more additional layers may be disposed on the outer surface of the outer layer 106. For example, in some embodiments of the present disclosure, a heat shrink layer (not shown) is disposed on the outer layer to apply a radially inward force to the multi-layer tube 100 during its formation. The heat shrink layer may be formed from a fluoropolymer or polyolefin material, such as polytetrafluoroethylene (PTFE) or fluorinated ethylene propylene copolymer (FEP). The heat shrink layer may be referred to as a shape-retaining structure because it maintains the overall shape of the multi-layer tube 100 during further processing, as described in more detail below.

[0040] A reinforcing layer in the form of a hypotube, coil, or other reinforcing structure formed from stainless steel, nitinol, or other material may optionally be incorporated into the multi-layer tube 100. When included, the reinforcing layer can provide support and / or structure to the multi-layer tube 100. In various embodiments of the present disclosure, the reinforcing layer is positioned between the tie layer and the outer layer, although it can also be positioned elsewhere within the multi-layer tube structure. For example, in embodiments of the present disclosure, the hypotube, coil, or other reinforcing structure is embedded in the inner layer 102 or the tie layer 104. In embodiments of the present disclosure, the multi-layer tube 100 excludes polymeric fibers. As used herein, the term "polymeric fiber" refers to a material made from polymeric fibers, threads, or yarns interlaced by any one of a variety of methods, such as, but not limited to, weaving or knitting.

[0041] The coil can have any suitable pitch and corresponding surface area coverage known and available in the art. In embodiments of the present disclosure, the coil has a surface area coverage of 25% to 75%, 30% to 70%, 40% to 60%, or 45% to 55%, including all ranges and subranges contained therein. In certain embodiments, the multi-layer tube 100 includes a stainless steel coil as a reinforcing layer.

[0042] The present disclosure is also directed to articles comprising the multilayer tubing. Examples of such articles include, but are not limited to, intravascular medical devices, including catheters and medical tubing. In embodiments of the present disclosure, the intravascular medical device comprises the multilayer tubing of the present disclosure. The intravascular medical device includes a catheter and / or a medical tubing.

[0043] Any one of a variety of methods may be used to form the multi-layer tube 100, including, but not limited to, film casting and ram extrusion. In some embodiments of the present disclosure, the inner layer 102 may be formed by extruding a material onto a metal substrate (e.g., a wire). After extrusion, the inner layer-coated substrate may be sintered at a temperature above about 345°C to fuse the grains of the inner layer 102 and form a substantially uniform inner layer 102. The product may then be cooled, and the inner layer 102 may be removed from the substrate. Other methods of forming the inner layer 102 are known and used in the art. It is further contemplated that a commercially available tube consisting essentially of the inner layer 102 may be obtained and processed to form the multi-layer tube 100. Examples of such commercially available tubing include, but are not limited to, those available from Zeus Industrial Products, Inc. (Orangeburg, South Carolina), Nordson Medical (Easton, Pennsylvania), Junkosha Inc. (Japan), TE Connectivity Corporation (Berwyn, Pennsylvania), Medibrane Ltd. (Israel), Creganna Unlimited Company (Ireland), and Duke Extrusion (Santa Cruz, California).

[0044] In embodiments of the present disclosure, the inner layer 102 is etched to its outer surface, while in other embodiments of the present disclosure, the inner layer 102 is not subjected to etching or other surface modification processes. Etching may, for example, remove a few hundred angstroms or more (e.g., about 2.5×10 -5 The etching may include chemically etching the inner layer 102 by exposing it to an etchant such as fluorine for a time effective to etch to a depth of about 1 mm.

[0045] The tie layer coating composition is applied to the outer surface of the inner layer using any suitable method. For example, the tie layer coating composition can be applied via dip coating, spray coating, painting, drip coating, extrusion coating, or other suitable coating methods. In embodiments, the tie layer coating composition includes a functionalized styrenic block copolymer in the form of a dispersion. For example, the functionalized styrenic block copolymer can be dispersed in a solvent (e.g., toluene) to form the tie layer coating composition. After application to the outer surface of the inner layer 102, the tie layer coating composition is dried to form the tie layer 104. In other embodiments of the present disclosure, the tie layer coating composition is a molten form of the functionalized styrenic block copolymer. After application to the outer surface of the inner layer 102, the molten tie layer coating composition is cooled and solidified to form the tie layer 104.

[0046] In embodiments including a reinforcing layer, the reinforcing layer is disposed on at least a portion of the surface of the tie layer 104. In some embodiments, such as when the reinforcing layer is a wire coil, the reinforcing layer can be embedded in the tie layer 104. For example, a wire can be wrapped around the multi-layer tube before or while the tie layer composition is drying to form the tie layer 104. In other embodiments of the present disclosure, the reinforcing layer can be disposed on an outer surface of the tie layer 104 (e.g., wrapped around the multi-layer tube following formation of the tie layer 104). In still other embodiments of the present disclosure, the reinforcing layer can be disposed on a portion of the surface of the inner layer prior to applying the tie layer coating composition.

[0047] In embodiments including an outer layer 106, the outer layer 106 is formed by disposing the material comprising the outer layer onto the tie layer 104. For example, the outer layer 106 may be disposed on the tie layer 104 by applying the outer layer as a coating to the tie layer 104 and / or the reinforcing layer. Any suitable form of coating the outer layer 106 to achieve the desired outer layer 106 may be used as needed. In another example, the polymeric material may be in the form of a tube into which a multi-layer tube including the inner layer 102 and the tie layer 104 is inserted. However, other methods of forming the outer layer 106 on the tie layer 104 may be used depending on the particular embodiment of the present disclosure.

[0048] In various embodiments of the present disclosure, a heat seal layer is further disposed on the multi-layer tube 100. The multi-layer tube 100, including the inner layer 102, tie layer 104, outer layer 106, and heat seal layer, is then laminated or melt processed in accordance with the present disclosure.

[0049] The multilayer tubing of the present disclosure exhibits greater peel strength than an otherwise identical multilayer tubing that does not include a tie layer containing a functionalized styrenic block copolymer. In embodiments of the present disclosure, the peel strength is improved by more than about 25%, more than about 50%, more than about 55%, more than about 100%, more than about 150%, or more than about 200%. In embodiments of the present disclosure, the peel strength is improved by about 25% to about 250%, about 30% to about 225%, about 50% to about 225%, about 100% to about 225%, about 50% to about 110%, or any range or subrange within these ranges. In embodiments of the present disclosure, the peel strength is greater than 8.5 Newtons (N), e.g., greater than about 9.0 N, greater than about 9.5 N, greater than about 10.0 N, greater than about 10.5 N, greater than about 11.0 N, greater than about 12.0 N, greater than about 13.0 N, greater than about 14.0 N, greater than about 14.5 N, greater than about 15.0 N, greater than about 15.5 N, greater than about 16.0 N, greater than about 16.5 N, or greater than about 17.0 N. In embodiments of the present disclosure, the peel strength is from about 8.5 N to about 20.0 N, from about 9.0 N to about 19.5 N, from about 9.5 N to about 19.0 N, from about 9.5 N to about 18.5 N, from about 10.0 N to about 18.0 N, from about 14.0 N to about 18.0 N, or any range or subrange therein.

[0050] Example The following examples are intended to better illustrate various aspects of the present disclosure, but are not intended to limit the scope of the disclosure.

[0051] In the examples below, the following materials were used:

[0052] PTFE Liner A is a 0.254 inch ID ram-extruded PTFE etched liner with a wall thickness of 0.035 inch supplied by Zeus Industrial Products Inc.

[0053] PTFE Liner B is a ram-extruded PTFE etched liner with an inside diameter of 0.254 inches and a wall thickness of 0.035 inches provided by Nordson Medical.

[0054] TECOFLEX EG-80A is an aliphatic polyether-based thermoplastic polyurethane available from The Lubrizol Corporation (Wickliffe, Ohio).

[0055] PEBAX 55D is a polyether block amide available from Arkema SA (France).

[0056] VESTAMID ML21 is a polyamide 12 available from Evonik Industries AG (Germany).

[0057] ESTANE 58810 is a thermoplastic polyurethane available from The Lubrizol Corporation (Wickliffe, Ohio).

[0058] KRATON FG1901G polymer is a linear triblock copolymer based on styrene and ethylene / butylene, functionalized with 1.4 wt% to 2.0 wt% maleic anhydride, and has a polystyrene content of 30%, and is available from Kraton Corporation (Houston, Texas).

[0059] Comparative samples (Samples C1-C12) using PTFE Liner A were obtained from Zeus with no tie layer, a tie layer formed from TECOFLEX EG-80A, a tie layer formed from PEBAX 55D, or a tie layer formed from Polyamide 12, as shown in Table 1.

[0060] Additional comparative samples (Samples C13-C20) were prepared by applying either PTFE liner B alone (Samples C13-C14) or tie layer compositions containing ESTANE 58810 (Samples C15-C20) to PTFE liner B while monitoring viscosity. The inner diameter of the PTFE liner was unsupported, and both ends were plugged to prevent the tie layer composition from contacting the inner surface of the PTFE liner. The tie layer had an average thickness of approximately 6 μm.

[0061] Six samples (Samples I1-I6) comprising tie layers according to various embodiments of the present disclosure were prepared by applying a tie layer composition comprising KRATON FG1901G polymer to PTFE liner B. Specifically, KRATON FG1901G polymer was melted in a graduated cylinder and applied to the PTFE liner at a controlled rate while monitoring the viscosity. The inner diameter of the PTFE liner was unsupported, and both ends were plugged to prevent the tie layer composition from contacting the inner surface of the PTFE liner. The tie layer had an average thickness of approximately 7.5 μm.

[0062] Samples were evaluated with and without reinforcement, as shown in Table 1. For samples with a reinforcement layer, a 0.004 inch x 0.012 inch x 0.024 inch pitch 304 stainless steel coil was used to provide 50% surface area coverage.

[0063] The outer layer was selected from one of three different materials: TECOFLEX EG-80A, PEBAX 55D, and VESTAMID ML21, as shown in Table 1.

[0064] Table 1: Sample composition [Table 1]

[0065] To construct the samples, PTFE liners (with or without tie layers as shown in Table 1) were stretched over hypotubes with an outer diameter of 0.63 mm (0.0249 inches) and a length of 30 cm (12 inches). The length of the PTFE liners ranged from about 20 cm to about 28 cm (about 8 inches to about 11 inches).

[0066] For specimens containing a reinforcement layer, the middle (or medial or inner) 12.7 cm (5 in) of the liner was wrapped with 0.1 mm (0.004 in) x 0.3 mm (0.012 in) 304 stainless steel wire at a 0.6 mm (0.024 in) pitch. The ends were terminated with a laser weld in single pulse mode with a 0.30 mm spot size at 180 V for 1.0 ms.

[0067] The outer layer indicated for each sample in Table 1, having a length similar to the corresponding PTFE liner, was placed on the sample. A 17.7 cm (7 inch) long strip of 9.5 mm (3 / 8 inch) FEP heat shrink was then placed on the sample. The middle 12.7 cm (5 inch) of each sample was laminated in a vertical laminator. Lamination parameters were determined based on the outer layer material, as shown in Table 2. The samples were removed from the laminator, the heat shrink layer was removed, and the samples were cut in half for testing.

[0068] Table 2: Lamination parameters [Table 2]

[0069] Peel strength was measured using an Instron tensile test with the parameters shown in Table 3, 5 units per test.

[0070] Table 3: Peel strength test parameters [Table 3]

[0071] To prepare the specimen containing the reinforcement layer for testing, the specimen was peeled away from the outer layer until the first few coil layers were exposed, ensuring data was only included from the delamination of the coil section. Displacement and force values ​​were zeroed. The specimen was then clamped in pneumatic grips, with the PTFE liner clamped in the lower grip and the corresponding outer layer of the specimen clamped in the upper grip. The specimen was inspected to ensure there was no slack in the PTFE liner or outer layer.

[0072] The data obtained are shown in Table 4 and Figures 2-5. In particular, the values ​​reported in Table 4 are the average displacement values ​​over a specific 20 mm range. Because of data variability, the displacement range varies from test to test; however, it is defined as the first 20 mm increase that occurred 10 mm after all test specimens in the same dataset stabilized. This average value is reported because it provided a consistent range of values. The values ​​reported in Table 4 are consistent with values ​​obtained by averaging the force values, excluding the values ​​for the TECOFLEX EG-80A outer layer and excluding the initial ramp-up and ramp-down values. Regarding the data obtained for specimens containing TECOFLEX EG-80A in the outer layer, the elasticity of the outer layer was believed to introduce noise and vibration into the data, and as a result, this data was excluded.

[0073] Table 4: Peel strength test results [Table 4]

[0074] As shown in Table 4, the addition of a reinforcing layer (e.g., coil wire) was found to reduce the peel strength for the outer layer of PEBAX 55D and VESTAMID ML21. Without being bound by theory, it is believed that the reinforcing layer reduces the ability of the PTFE liner to bond to the outer layer. In particular, visual inspection of the samples showed that in sections where the liner and reinforcing layer contacted, etching of the liner remained, while in sections where the outer layer contacted the liner, etching was removed during the peel test.

[0075] However, the addition of the tie layer significantly reduced the negative effect of the reinforcement layer on peel strength, as shown in Figure 2 and Table 5. In particular, the samples containing tie layers (including tie layers formed from TECOFLEX EG-80A, PEBAX 55D, VESTAMID ML21, ESTANE 58810, and KRATON FG1901) exhibited an average decrease in peel strength of only 9.21% as a result of the addition of the reinforcement layer, compared to an average decrease of 39.44% in peel strength exhibited by samples without a tie layer but including a reinforcement layer.

[0076] Table 5: Comparison of the impact of various tie layer chemistries [Table 5]

[0077] However, the tie layer did increase adhesion with varying amounts, as shown in Figures 2-5 and Table 5. Notably, tie layers containing KRATON FG1901 improved the peel strength of the liners compared to liners with tie layers containing TECOFLEX EG-80A, PEBAX 55D, VESTAMID ML21, or ESTANE 58810. Notably, including VESTAMID ML21 as a tie layer (Samples C11 and C12) actually reduced peel strength compared to other identical multilayer tubes that did not include the VESTAMID ML21 tie layer (e.g., Samples C5 and C6). The effect of using tie layers containing TECOFLEX EG-80A, PEBAX 55D, and VESTAMID ML21 on PTFE Liner A, which includes a reinforcing layer and an outer layer corresponding to the tie layer, is shown in Figure 3.

[0078] Figure 4 shows the peel strength of various samples without a reinforcement layer with VESTAMID (nylon) and PEBAX outer layers. As shown in Figure 4, the samples containing the KRATON tie layer show increased peel strength for both outer layer chemistries.

[0079] Figure 5 shows the peel strength of various samples containing a PTFE liner B, a reinforcing layer, and a PEBAX outer layer. The ESTANE tie layer (C18) showed increased peel strength over the control (C14), while the use of a KRATON tie layer (I4) resulted in increased peel strength even over the ESTANE tie layer.

[0080] The baseline adhesion of the samples containing PTFE liner B was greater than the baseline adhesion of the samples containing PTFE liner A for both the samples with and without the reinforcing layer (55.74% and 29.73%, respectively).

[0081] While various inventive aspects, concepts, and features of the present disclosure may be described and illustrated herein as embodied in combination in exemplary embodiments of the present disclosure, these various aspects, concepts, and features may be used in numerous alternative embodiments of the present disclosure, either individually or in various combinations and subcombinations thereof. Unless expressly excluded herein, all such combinations and subcombinations are intended to be within the scope of the present application. Still further, while various alternative embodiments of the present disclosure with respect to various aspects, concepts, and features of the present disclosure—e.g., alternative materials, structures, configurations, methods, devices, and components, alternative embodiments with respect to form, fit, and function—may be described herein, such descriptions are not intended to be a complete or exhaustive list of available alternative embodiments of the present disclosure, whether currently known or later developed. Those skilled in the art may readily adopt one or more of the aspects, concepts, or features of the present disclosure into additional embodiments of the present disclosure and uses within the scope of the present application, even if such aspects of the present disclosure are not explicitly disclosed herein.

[0082] Furthermore, even if some features, concepts, or aspects of the present disclosure are described herein as being preferred arrangements or methods, such description is not intended to imply that such features are essential or required unless expressly so described. Still further, to aid in understanding the present application, exemplary or representative values ​​and ranges may be included, but such values ​​and ranges are not to be construed in a limiting sense, and are intended to be critical values ​​or ranges only when expressly so described.

[0083] Moreover, while various aspects, features, and concepts may be expressly identified herein as inventive or forming part of the disclosure, such identification is not intended to be exclusive; rather, there may be inventive aspects, concepts, and features that are fully described herein without being expressly identified as such or part of a particular disclosure, the disclosure instead being set forth in the appended claims. The description of an exemplary method or process is not limited to the inclusion of every step, as required in all cases, nor should the order of presentation of the steps be construed as essential or required unless expressly so stated. The words and phrases used in the claims have all of their ordinary meanings and are not limited in any way by the description in the specification.

Claims

1. an inner layer comprising polytetrafluoroethylene (PTFE), the inner layer having an inner surface defining an inner diameter of the multilayer tube and an outer surface spaced from the inner surface by a thickness of the inner layer; and a tie layer comprising a functionalized styrene block copolymer disposed on the outer surface of the inner layer A multi-layer tube comprising:

2. 10. The multi-layer tubing of claim 1, wherein the functionalized styrene block copolymer comprises a maleic anhydride grafted styrene block copolymer.

3. 3. The multi-layer tubing of claim 1 or 2, wherein the functionalized styrene block copolymer comprises maleic anhydride grafted poly(styrene-ethylene / butylene-styrene) (SEBS-g-MA).

4. The multi-layer tubing of any one of claims 1 to 3, wherein the functionalized styrene block copolymer comprises greater than 25% by weight of styrene.

5. The multi-layer tubing of any one of claims 1 to 4, further comprising an outer layer disposed on the tie layer such that the tie layer is disposed between the inner and outer layers.

6. 6. The multi-layer tubing of claim 5, wherein the outer layer comprises polyurethane, polyamide, polyether, polyamide / polyether block copolymer, polyester, copolyester, stainless steel, glass, or a combination thereof.

7. 7. The multi-layer tube of claim 5 or claim 6, wherein the outer layer comprises a polyamide / polyether block copolymer.

8. The multi-layer tubing of any one of claims 1 to 7, wherein the tie layer has a thickness of about 2.5 µm to about 30 µm.

9. The multilayer tube according to any one of claims 1 to 8, further comprising a reinforcing layer.

10. The multi-layer tubing of claim 9 , wherein the reinforcing layer comprises a wire coil.

11. The multilayer tube according to any one of claims 1 to 10, wherein the outer surface of the inner layer is etched.

12. The multi-layer tubing of any one of claims 1 to 11, wherein the multi-layer tubing exhibits at least about a 25% increase in peel strength compared to an otherwise identical multi-layer tubing that does not include a tie layer.

13. 13. The multi-layer tubing of any one of claims 1 to 12, wherein the multi-layer tubing exhibits an increase in peel strength of about 25% to about 250% compared to an otherwise identical multi-layer tubing that does not include a tie layer.

14. forming a tie layer from a tie layer coating composition comprising a functionalized styrene block copolymer on the outer surface of an inner layer comprising polytetrafluoroethylene (PTFE); A method for producing a multilayer tube comprising:

15. Etching the outer surface of the inner layer prior to forming the tie layer. The method of claim 14 further comprising:

16. 16. The method of claim 14 or claim 15, wherein forming the tie layer comprises immersing an inner layer in the tie layer coating composition.

17. The method of any one of claims 14 to 16, further comprising forming a reinforcing layer formed from a wire coil along at least a portion of the length of the multi-layer tube.

18. The method of claim 17 , wherein forming the reinforcing layer comprises wrapping a wire around the tie layer.

19. forming an outer layer comprising polyurethane, polyamide, polyether, or a combination thereof over the tie layer such that the tie layer is disposed between the outer layer and the inner layer; The method of any one of claims 14 to 18, further comprising:

20. The process of any one of claims 14 to 19, wherein the functionalized styrene block copolymer comprises maleic anhydride grafted poly(styrene-ethylene / butylene-styrene) (SEBS-g-MA).

21. An intravascular medical device comprising the multilayer tube of any one of claims 1 to 14 or the multilayer tube formed by the method of any one of claims 14 to 20.

22. A catheter comprising the multilayer tube according to any one of claims 1 to 14 or the multilayer tube formed by the manufacturing method according to any one of claims 14 to 20.

23. A medical tube comprising the multilayer tube according to any one of claims 1 to 14 or formed by the method according to any one of claims 14 to 20.

24. an inner layer comprising a fluorinated polymer, the inner layer having an inner surface defining an inner diameter of the multilayer tubing and an outer surface spaced from the inner surface by a thickness of the inner layer; and a tie layer comprising a functionalized styrenic block copolymer disposed on the outer surface of the inner layer A multi-layer tube comprising:

25. 25. The multi-layer tubing of claim 24, wherein the functionalized styrene block copolymer comprises a maleic anhydride grafted styrene block copolymer.

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