Catheter shaft with fluoropolymer inner liner and related methods

Abstract

To provide a catheter with an inner liner with high lubricity and durability, while maintaining a lower manufacturing cost and processability.SOLUTION: A catheter 100 comprises a proximal handle 110, a distal tip 104, and a shaft 102 extending between the proximal handle and the distal tip. The shaft comprises an outer polymer layer, and an inner polymer layer disposed adjacent to the outer polymer layer and defining an internal lumen. The inner polymer layer includes a blend of two or more polymers, and the blend of two or more polymers includes PTFE and one or more copolymers.SELECTED DRAWING: Figure 1

Description

Background Art

[0001] A variety of disposable heart introducers or delivery catheters are widely used in hospitals not only for performing electrophysiology and atrial fibrillation (EP / AF)-related clinical procedures, but also for facilitating the implantation of heart valves and heart occlusive devices and cardiac rhythm management (CRM) pacing leads. To meet the associated functional requirements in terms of structural complexity (e.g., axial flexibility, surface lubricity, torsional resistance, column strength, and torqueability, etc.), such introducers or delivery catheters are often manufactured as tubular shafts having a central lumen defined by an inner liner, onto which an outer polymeric member is adhesively bonded seamlessly to form a polymeric sheath or related shaft segment.

[0002] To facilitate the introduction or delivery of medical devices (e.g., EP mapping or ablation catheters, CRM pacing leads, heart occlusive plugs, percutaneous heart pumps, replacement mitral or aortic valves, etc.), the central lumen, such as that defined by the polymeric inner liner of an introducer sheath or delivery catheter shaft, should exhibit consistent surface lubricity and durable ablation resistance, minimizing the frictional resistance to the advancement of the device through the entire length of the shaft and tortuous vasculature on the way to the target anatomical site.

[0003] Polymer inner liners can generally be manufactured from polytetrafluoroethylene (PTFE) homopolymer materials among all known polymer materials due to their high material lubricity (lowest coefficient of friction in the dry state). However, PTFE supplied in powder form is not melt processable and must be ram or paste extruded. Due to its characteristic fibrous structure, such extruded PTFE liners can have weak lateral strength and poor wear resistance. Thus, a heart introducer or delivery catheter including such a PTFE inner liner may be susceptible to damage to the material in the form of fibrous cracks or splits.

Summary of the Invention

[0004] Embodiments include a catheter comprising a proximal handle, a distal tip, and a shaft extending between the proximal handle and the distal tip. The shaft comprises an outer polymer layer and an inner polymer layer disposed adjacent to the outer polymer layer and defining an internal lumen. The inner polymer layer comprises a blend of two or more polymers, and the blend of two or more polymers comprises PTFE and one or more copolymers.

[0005] Embodiments further include a catheter liner disposed adjacent to the outer polymer layer and defining an internal lumen. The inner polymer layer comprises a blend of two or more polymers, and the blend of two or more polymers comprises PTFE and one or more copolymers.

[0006] Further embodiments include a method of manufacturing a catheter liner. The method includes melt blending PTFE fine powder and a TFE-containing copolymer sufficient to form a dispersion blend, melt extruding the dispersion blend to form an inner layer, chemically etching the inner layer to form a chemically activated inner layer, and contacting the activated inner layer with at least one additional layer. The amount of PTFE in the dispersion blend is 1 wt% to 35 wt% of the total blend.

Brief Description of the Drawings

[0007]

Figure 1

[0008]

Figure 2

[0009]

Figure 3

[0010]

Figure 4

[0011]

Figure 5

[0012]

Figure 6A

Figure 6B

Modes for Carrying Out the Invention

[0013] Embodiments of the present specification describe an inner catheter liner and related methods that provide a liner with high lubricity and durability while maintaining lower manufacturing costs and processability. In one embodiment, one or more melt-processable tetrafluoroethylene (TFE)-containing copolymers are blended with a certain amount of PTFE fine powder and melt-extruded into an integral and lubricious fluoropolymer inner liner. Since PTFE is not melt-processable, such a melt-processable TFE-containing copolymer blend, or an inner liner melt-extruded from a fluoropolymer blend, has high lubricity, higher wear resistance, and improved abrasion resistance, as well as ease of manufacture and cost savings, compared to a conventional or common inner liner ram-extruded from only PTFE homopolymer. In addition to its high lubricity and wear resistance, such an inner liner melt-extruded from a TFE-containing copolymer blend has little fibrous morphological structure that causes problems in the use of medical devices over time. TFE-containing copolymer resins, or fluorinated copolymer resins of tetrafluoroethylene (TFE), are generally melt-processable and have slightly lower material lubricity than PTFE inner liners, but can be easily used to manufacture an integral fluoropolymer inner liner with equivalent or better lateral and axial strength and longer-lasting wear and abrasion resistance. To enhance material lubricity, fluoropolymer blends or compounds of TFE-containing copolymer resins are developed by incorporating PTFE fine powder as a lubricant to enhance performance due to its inherent chemical compatibility with PTFE homopolymer. The TFE units of the TFE-containing copolymer can be represented by the following structure: [Chemical formula]

[0014] In additional embodiments, a cross-linked PTFE inner liner can be utilized. The cross-linking between the linear PTFE polymer chains prevents axial delamination of the inner liner consisting of highly oriented PTFE fibrils formed by ram extrusion, while improving wear and abrasion resistance while maintaining maximum lubricity. In another embodiment, a small amount of a TFE-containing copolymer is added to the PTFE fine powder to obtain a fluoropolymer blend for forming the inner liner by ram extrusion. The addition of the TFE-containing copolymer breaks down the fibrous PTFE morphology and creates a more durable inner liner.

[0015] Referring to FIG. 1, a perspective view of a catheter 100 according to some embodiments is shown. The catheter shaft 102 includes a distal end or tip 104 and a proximal end 106. The handle 110 can be coupled or integrated with the shaft proximal end 106 to control or manipulate the catheter shaft 102. A hub or port 112 can be disposed near the handle 110 or the proximal end 106, for example, to introduce a medical device. The valve 108 may be in contact with the hub 112, the proximal end 106, or both.

[0016] The catheter shaft 102 may include one or more catheter shaft sections 114. The catheter shaft 102 may be manufactured from a plurality of sections 114, each of which may be manufactured or designed with different materials or material ratios to achieve structural flexibility and maneuverability. For example, one section 114 can have higher torsional or torque resistance than another section 114. The sections 114 may be formed as an integral shaft in the manufacturing process. Alternatively, the sections 114 may be manufactured separately and then attached or assembled.

[0017] Referring to FIG. 2, a cross-sectional view of catheter 100 (along line A-A of FIG. 1) according to some embodiments is shown. Inner liner or layer 202 forms a central lumen 212 within catheter shaft 102. An optional reinforcement layer 204 surrounds inner liner 202. An optional intermediate layer 206 is present between reinforcement layer 204 and outer layer 208. Outer heat shrinkable tube or layer 210 is disposed in contact with outer layer 208.

[0018] Inner liner 202 may be integral with the entire catheter shaft 102 or may be part of one or more catheter sections 114.

[0019] The inner liner 202 can have different compositions or material ratios, for example, in one catheter section 114 and another catheter section. The inner liner 202 can be manufactured from a fluoropolymer blend of one or more TFE-containing copolymers and polytetrafluoroethylene (PTFE) homopolymer as a secondary component. The amount of PTFE homopolymer in the blend can be from about 1 wt% to about 35 wt%. The amount of PTFE homopolymer can be, for example, from about 5 wt% to about 15 wt%, from about 3 wt% to about 20 wt%, from about 5 wt% to about 30 wt%, or from about 0.5 wt% to about 25 wt%. One or more copolymers are chemically derived from TFE as a comonomer, and such copolymers can contain, for example, more than 5% TFE comonomer, or from about 5% to about 50% TFE comonomer, or from about 10% to about 40% TFE comonomer. Specific examples of TFE-containing copolymers include perfluorocopolymers such as perfluoroalkoxyalkane (PFA) and fluorinated ethylene propylene copolymer (FEP). Further examples include partially fluorinated copolymers such as ethylene-tetrafluoroethylene copolymer (ETFE), ethylene-fluorinated ethylene-propylene copolymer (EFEP), and THV thermoplastic elastomer. ETFE is essentially a 1:1 alternating copolymer of ethylene and tetrafluoroethylene. EFEP is a random terpolymer of ethylene, tetrafluoroethylene, and hexafluoropropylene. THV is, for example, a random terpolymer of tetrafluoroethylene (TFE), hexafluoropropylene (HFP), and vinylidene fluoride (VDF).

[0020] PFA copolymers are generally described as tetrafluoroethylene (TFE)-perfluoroalkoxy (PFA) copolymers, or simply PFA copolymers, which are synthesized by using the comonomers of TFE (CF2=CF2) and perfluoroalkyl vinyl ether (CF2=CF-O-R F ), that is, as follows.

Chemical formula

[0021] The FEP copolymer is generally known as a tetrafluoroethylene-hexafluoropropylene copolymer having the following molecular structure. [Chemical formula] Exemplary FEP copolymer resins can include Teflon® FEP, Neoflon™ FEP, Dyneon™ FEP, etc. Generally, the FEP copolymer has a relatively low melting point of about 260 °C.

[0022] A family of terpolymers chemically derived from tetrafluoroethylene (TFE), hexafluoropropylene (HFP), and vinylidene fluoride (VDF) comonomers is generally known as THV thermoplastic elastomers and has the following exemplary structure: [Chemical formula]

[0023] Exemplary families of THV thermoplastic elastomer materials are commercially available under the trade name Dyneon(™) THV. These THV materials have various mechanical properties suitable for different design requirements. Depending on the different ratios of TFE, HFP, and VDF comonomers, the THV thermoplastic elastomer materials have various melting temperatures of about 120 to 225 °C.

[0024] ETFE copolymers are chemically derived from ethylene and tetrafluoroethylene comonomers and have the following general molecular structure.

Chemical formula

[0025] EFEP copolymers are chemically derived from ethylene, tetrafluoroethylene, and hexafluoropropylene comonomers and have the following general molecular structure.

Chemical formula

[0026] Using TFE-containing copolymer materials with relatively low melting points (such as EFEP, THV copolymer, FEP, etc.), a lubricious fluoropolymer blend can be prepared that includes PTFE fine powder and an additional perfluoropolyalkyl ether or perfluoropolyether (PFPE) liquid lubricant in an amount of about 0 to 10 wt%, or 1% to 10 wt%. Such a fluoropolymer blend can contain the liquid lubricant, for example, in an amount of about 2 to 5 wt%. In one example, commercially available PFPE liquid lubricants are poly(hexafluoropropylene oxide) (HFPO) as shown below,

Chemical formula

Chemical formula

Chemical formula

Chemical formula

[0027] One of the above TFE-containing copolymer resins, or an integral, lubricious inner liner formed by melt extrusion molding of a base fluoropolymer blend, still has a very low surface energy comparable to that of PTFE homopolymer materials. In order to chemically adhere to the outer layer 208 or any layer adjacent to the outside of the liner 202, which is generally composed of a polar polymer material, the outer surface of such an inner layer 202 can be chemically etched using a sodium-containing etchant such as a solution of sodium naphthalide in THF or glyme solvent, similar to the PTFE inner liner formed by ram extrusion molding. Chemical etching chemically activates the outer surface of the inner liner 202 and thermally bonds the liner 202 to the outer polymer layer 208 (or intermediate layer 206 or any adjacent outer layer) of the shaft 102, while the inner surface of the liner 202 remains unaffected in order to define the surface lubricity of the central lumen of the shaft.

[0028] In an additional embodiment, the inner liner 202 may be an irradiated crosslinked PTFE tube (i.e., xPTFE tube) (the same or similar to tube 210), or a heat shrinkable PTFE tube having a crosslinked network structure. The introduction of crosslinking between highly oriented PTFE fibrils significantly increases the transverse strength of the xPTFE tube, which is manufactured by ram extrusion molding and has a fibrous structure. As a result, the material resistance to fibrous splitting or cracking and continuous wear and abrasion is significantly increased without impairing the inherent material lubricity.

[0029] In one embodiment, crosslinking of the PTFE tube induced by irradiation can be achieved by adding E-beam irradiation at a later stage of the sintering zone under an inert gas purge and precise temperature control near 340°C. Alternatively, E-beam crosslinking of the PTFE tube after extrusion can also be achieved. In this case, a PTFE tube cut to a finite length from one coil of a ram-extruded tube is attached onto a support metal (stainless steel) mandrel and then placed in a heated E-beam chamber under precise (e.g., at about 340°C) temperature control and an inert gas purge (e.g., argon, N2, etc.).

[0030] Typical polymer materials can be crosslinked in various phases (i.e., solid or molten state) via ionizing irradiation (e.g., E-beam, gamma-ray irradiation, etc.). An example is heat-shrinkable tubes made of various semi-crystalline polymer materials. For example, a polymer tube before extrusion is crosslinked in its solid state and then, when heated to a high temperature near its melting temperature in an inert oxygen-free environment, thermally expanded with a radial expansion ratio and then rapidly cooled to the solid state to obtain a shrinkable dimension. Such heat-shrinkable tubes tend to shrink back to their non-expanded dimensions when heated due to the memory effect of the material provided by the crosslinked network structure of the material.

[0031] PTFE homopolymer materials do not normally crosslink via general solid-state ionization irradiation because the material is prone to degradation via irradiation-induced chain scission. Such irradiation-induced chain scission reactions increase with irradiation temperature when the PTFE material is in the solid state. However, the irradiation-induced crosslinking reaction within the molten PTFE material becomes dominant over irradiation-induced chain scission when the irradiation temperature is sufficiently higher than the melting point. Considering the competing effect of thermally induced chain scission on the progress of the irradiation-induced crosslinking reaction, E-beam irradiation for PTFE homopolymer materials can be carried out at a preferred irradiation temperature near 340 °C and exposed to an inert, oxygen-free environment (e.g., argon, helium, nitrogen, etc.). Therefore, the ram extrusion process can be modified to manufacture xPTFE tubes by performing E-beam irradiation in the latter half of the sintering stage. After E-beam crosslinking and any thermal expansion and quenching, the xPTFE tubes exhibit significantly improved ablation resistance without being affected by axial cracks and fissures. Therefore, such xPTFE tubes can be used as an integral and lubricious inner liner 202 for manufacturing the catheter shaft 102 or shaft segment 114. To combine with the outer member 208, the outer surface of the xPTFE tube or such an inner liner 202 must also be chemically treated using the same sodium naphthalide solution in THF or glyme solvent as outlined above. The outer layer 208 may be directly adjacent to the inner liner 202 or may be disposed adjacent to any reinforcing layer 204 and any intermediate layer 206. The outer layer 208 may include, for example, multiple layers. Each layer within the outer layer 208 may be manufactured from the same material or different materials. Any layer within the outer layer 208 may be a chemically compatible or bondable polymer material. Various polymer materials with synergistically balanced material properties (e.g., modulus, tensile strength, material toughness, melt processability and thermal stability, chemical resistance, and compatibility with other constituent materials, etc.) can be selected to prepare the single-layer or multi-layer outer polymer layer 208 of the introducer sheath or catheter shaft 102 and related shaft segments or sections 114.

[0032] For example, such a polymer material for the outer polymer layer 208 generally includes a series of segmented block copolymers based on various thermoplastic elastomer materials, such as polyamide-based thermoplastic elastomers (i.e., poly(ether-block-amide) copolymers), having constituent hard segments derived from methylene diphenyl diisocyanate (MDI), and constituent soft segments derived from different types of long-chain polyglycols and combinations of these polyglycols (e.g., polyether glycols, polycarbonate glycols, dihydroxylated siloxane polymers, etc.), and may be selected from thermoplastic polyurethane elastomers, polyester-based thermoplastic elastomers (i.e., poly(ether-co-ester) block copolymers), etc. Alternatively, the thermoplastic material may be considered for the outer polymer layer 208 that requires relatively high modulus, column strength, and torque properties. These materials may include engineering thermoplastic polyurethanes, polyamides (e.g., PA11, PA12, PA612, etc.), polyesters (i.e., poly(ethylene terephthalate) or PET, poly(butylene terephthalate) or PBT, etc.), poly(bisphenol A carbonate), etc.

[0033] For a steerable introducer and high-performance delivery catheter device, any reinforcing layer 204 may be utilized. This layer 204 includes a tubular mesh woven from a plurality of threads of metal wire (e.g., stainless steel or nickel-titanium alloy (or nitinol)) incorporated at the interface between the inner liner 202 and the outer polymer layer 208, and can form a braided multilayer catheter shaft 102 or an associated shaft segment 114. Further, in some other embodiments, the reinforcing layer 204 may be embedded within the outer layer 208 or the intermediate layer 206 at different radial positions.

[0034] Any intermediate layer 206 may act as a matrix material layer, for example, together with the reinforcement layer 204. In some embodiments, the intermediate layer 206 can be extruded onto the reinforcement layer 204 to form the matrix material layer. In other embodiments, the intermediate layer 206 may be extruded separately and then slid around the reinforcement layer 204 as part of the catheter shaft 102 assembly.

[0035] In some embodiments, the intermediate layer 206 may be superelastic with respect to the inner liner 202. In other words, the intermediate layer 206 may have a lower flexural modulus and a higher yield strain than the inner liner 202. The lower the flexural modulus and the higher the yield strain of the intermediate layer 206 with respect to the inner liner 202, the more the steerability and torsional resistance of the catheter shaft 102 are promoted.

[0036] In some embodiments, the intermediate layer 206 forms the outermost layer of the catheter shaft 102 and may act as or replace the outer layer 208. Alternatively, the outer layer 208 may be formed around the intermediate layer 206. The outer layer 208 can be formed by extruding a polymeric material onto the intermediate layer 206. In some embodiments, the outer layer 208 and the intermediate layer 206 are co-extruded onto the reinforcement layer 204. In another example, the outer layer 208 may be extruded separately and then slid around the intermediate layer 206.

[0037] Materials suitable for the intermediate layer 206 can be selected from, but are not limited to, styrenic block copolymers (e.g., including Kraton™ D (styrene-butadiene-styrene (SBS) triblock copolymer and styrene-isoprene-styrene (SIS) triblock copolymer), Kraton™ G (styrene-ethylene / butylene-styrene copolymer and styrene-ethylene-styrene (SEPS) copolymer, and SIBSTAR™ styrene-isobutylene-styrene triblock copolymer), thermoplastic olefins (TPO) and elastomer alloys (e.g., Santoprene™ and Versaflex™), thermoplastic polyurethanes (e.g., Pellethane™, Estane™, Tecoflex™, Tecothane™, Tecoplast™, and Tecophilic™ TPU), poly(ether-b-amide) (e.g., Pebax™, Vestamid™ E, and Grilamide™ ELY), poly(ether-ester) (e.g., Hytrel™), ionomer thermoplastic elastomers (e.g., Surlyn™), and any combination thereof. Particularly suitable substances for the intermediate layer 206 include, but are not limited to, Pebax™ 4033, Pebax™ 5033, Pellethane™ 2363-55D, and Surlyn™ 9320.

[0038] Referring to FIG. 3, a flowchart diagram of a method (300) for manufacturing a catheter shaft using melt processing of an inner liner or layer according to some embodiments is shown. One or more TFE-containing copolymers are melt blended (306) with PTFE fine powder by using conventional polymer mixing. One or more optional liquid lubricants may be added (305) to the blend. The resulting fluoropolymer blend is then melt extruded (308) to form an inner liner or layer. Chemical etching 312 of the outer surface of the inner layer is performed to obtain a chemically etched inner liner / inner layer, which is utilized to form (316) a catheter shaft (or shaft segment). Additional components or layers, such as an outer layer, and optionally an intermediate layer, and optionally a reinforcing layer, etc., may then be assembled or formed (318) either subsequently or together.

[0039] As described above, a fluoropolymer blend of one or more TFE-containing copolymers containing PTFE fine powder (302) in a lesser weight is dry blended and melt mixed (i.e., melt blended (306)). The melt mixing includes introducing the PTFE and the TFE-containing copolymer into a single-screw or twin-screw extrusion molding machine, where all components of the blend are completely melted, mixed, then cooled and pelletized. The resulting pelletized fluoropolymer blend is then melt extruded (308) through a tubular die to obtain a tubular inner liner by using a single-screw extrusion molding machine. In such a fluoropolymer blend, by maintaining the amount of PTFE fine powder in an amount significantly less than that of the TFE-containing copolymer, the presence of solid PTFE fine particles sufficiently dispersed in the high-viscosity PTFE homopolymer material or melt does not prevent the inherent melt processability of the primary TFE-containing copolymer material composed of the melt fluoropolymer blend material during the tube extrusion molding of the inner layer. The outer surface of the inner layer is chemically activated by using chemical etching (312). The resulting etched inner layer is then thermally integrated and joined (316) to form a catheter shaft and can be integrated and joined with other components (e.g., an outer layer, and optionally an intermediate layer and a reinforcing layer) to form a catheter shaft (or shaft segment) via a so-called thermal lamination or reflow process (318).

[0040] The etched inner liner, outer polymer layer 208, and optionally reinforcing layer 204 and intermediate layer 206 (see FIG. 2) may be sequentially assembled onto a rod-shaped metal mandrel (see 502 in FIG. 5) whose outer diameter matches the central lumen of the liner. The resulting assembly may then be completely encapsulated by a heat shrink tube 210. When heated to a predetermined temperature (see heat source 504 in FIG. 5), the outer polymer layer 208 and / or the intermediate polymer layer 206 partially or completely melt and flow to fill any voids within the assembly under the radial pressure generated by the shrinkable tube 210. This is generally known as a heat lamination or reflow process for manufacturing a multi-layer catheter shaft 102 (or shaft segment 114). By reflow, the polymer layers bond together seamlessly by heat fusion, optionally together with any reinforcing layer 204 embedded therebetween, such that an integral shaft 102 or integral shaft segment 114 is obtained when the shrinkable tube 210 is removed.

[0041] Referring to FIG. 4, a flowchart diagram of a method (400) for manufacturing a catheter shaft using an inner liner ram extruded from a PTFE fluoropolymer blend material according to some embodiments is shown. A PTFE fine powder and one or more TFE-containing copolymers in fine powder form are dry blended in a suitable solvent and sufficiently dispersed (402) to prepare a hybrid PTFE paste. The hybrid PTFE paste is then compression molded (406) as a hybrid PTFE preform and ram extruded (410) to form a ram extruded hybrid PTFE inner liner. By using chemical etching (312), the outer surface of the inner layer is chemically activated and an etched hybrid PTFE inner layer is obtained. The catheter shaft or shaft segment is formed (316) by a reflow process using the etched inner liner (as described above with respect to FIG. 4). Additional components or layers, such as an outer layer, and optionally an intermediate layer, and optionally a reinforcing layer, etc., may then be assembled or formed (318) either subsequently or together.

[0042] A hybrid PTFE paste composed of PTFE fine powder and a chemically compatible TFE-containing copolymer in fine powder form is prepared (402) and can be used for ram tube extrusion molding (410). Examples of copolymers include PFA, FEP, and / or ETFE which have a melting temperature as high as that of PTFE homopolymer and are commercially available in micronized fine powder form. To prepare the hybrid PTFE paste, about 50-99%, or about 70-90% of PTFE fine powder is thoroughly dry blended with other TFE-containing copolymers in fine powder form, and then, as in the case of 100% PTFE fine powder, it is liquid mixed with (aromatic) hydrocarbon solvents and / or fluorinated hydrocarbon fluids (e.g., Isopar™ E isoparaffinic hydrocarbon fluid). The hybrid PTFE paste is then processed (e.g., compression molding (406)) into a preform or billet. The hybrid PTFE preform or billet is intermittently fed to a ram extruder for ram tube extrusion molding 410, which can include solvent evaporation and sintering by a series of vacuum ovens, and optional E-beam crosslinking in the later stage of sintering.

[0043] TFE-containing copolymer materials, such as PFA, FEP, and ETFE, generally have a lower melting temperature and crystallization temperature than PTFE homopolymer, but have equivalent thermal stability. During sintering, other copolymer materials thermally fuse with the PTFE matrix or PTFE fibrils. As a result, upon cooling after sintering, other TFE-containing copolymers crystallize faster because they greatly disrupt the oriented phase morphology of the PTFE matrix (the undisturbed fibrous form 600 of a pure PTFE liner is shown in FIGS. 6A - B). Therefore, the fluoropolymer inner liner ram extruded from the hybrid PTFE paste shows substantially the same surface lubricity as a pure PTFE inner liner, is integral and lubricious, and does not show phenomena of axial splitting, cracking, and insufficient ablation and wear in related engineering tests.

[0044] The hybrid PTFE paste of PTFE and one or more TFE-containing copolymers may be ram extruded (410). In this process, the amount of PTFE relative to the TFE-containing copolymer in the paste can be from about 50 wt% to about 99 wt%. Conversely, the amount of one or more TFE-containing copolymers can include from about 1 wt% to about 50 wt%, from about 5 wt% to about 35 wt%, or from about 10 wt% to about 25 wt%. Ram tube extrusion (410) using a TFE-containing copolymer material in the form of a fine powder and also a PTFE homopolymer in the form of a fine powder can be utilized to prepare a hybrid fluoropolymer tube or inner liner. The inclusion of perfluorinated copolymer materials such as PFA, FEP, and ETFE retains the high material lubricity of the PTFE homopolymer material, while the inherent fibrous structure of the PTFE homopolymer is significantly disrupted or absent due to the occurrence of co-crystallization of the copolymer material between the oriented PTFE fibrils. To produce such an integral lubricious fluoropolymer inner tube or liner, both the PTFE homopolymer material and the TFE-containing perfluorinated copolymer material (e.g., PFA, ETFE, and FEP) are supplied in the form of fine powders, dry mixed, and then mixed with a hydrocarbon lubricant or solvent to obtain a hybrid PTFE paste for ram tube extrusion (410). The ram tube extrusion process (410) requires the preparation (406) of a preform and includes a plurality of process steps including, for example, ram extrusion through a tubular die, solvent evaporation, and sintering. Optionally, an E-beam crosslinking step after the sintering process step can be added to obtain an integral and lubricious crosslinked inner tube made of the hybrid PTFE fluoropolymer paste (404) (as discussed in the above alternative embodiments).

[0045] Similar to the hybrid PTFE inner layer ram extruded from the hybrid PTFE paste as described above (Figure 4), an xPTFE inner layer comprising a 100% PTFE homopolymer material (302) can be ram extruded using an E-beam crosslinking process integrated with the ram extrusion. Such an xPTFE inner layer can be chemically etched to obtain an etched inner layer, which is then assembled (318) with the outer layer 208, and optionally the reinforcement layer 204 and the intermediate layer 206, to form (316) a catheter shaft or shaft segment. Additional components or layers, such as an outer layer, and optionally an intermediate layer, and optionally a reinforcement layer, etc., can be assembled or formed (318) subsequently or together.

[0046] This specification describes various embodiments of apparatuses, systems, and / or methods. Numerous specific details are set forth in order to provide a thorough understanding of the overall structure, function, manufacture, and use of the embodiments described herein and shown in the accompanying drawings. However, it will be understood by those skilled in the art that the embodiments may be practiced without such specific details. In other instances, well-known operations, components, and elements have not been described in detail so as not to obscure the embodiments described herein. Those skilled in the art will appreciate that the embodiments described and illustrated herein are non-limiting examples, and thus the specific structural and functional details disclosed herein may be representative and not necessarily limit the scope of the embodiments, the scope of which is defined only by the appended claims.

[0047] References throughout this specification to "various embodiments", "some embodiments", "one embodiment", or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases "in various embodiments", "in some embodiments", "in one embodiment", or "in an embodiment" throughout this specification are not necessarily all referring to the same embodiment. Further, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Accordingly, a particular feature, structure, or characteristic illustrated or described in connection with one embodiment may be combined, in whole or in part, with the features, structures, or characteristics of one or more other embodiments without limitation, provided such combination is not illogical or non-functional.

Claims

1. A catheter comprising: A proximal handle; a distal tip; and a shaft extending between the proximal handle and the distal tip, The shaft is an outer polymer layer; an inner polymeric layer disposed adjacent to the outer polymeric layer and defining an inner lumen; Equipped with the inner polymer layer comprises a blend of two or more polymers; A catheter, wherein the blend of two or more polymers comprises PTFE and one or more copolymers.

2. The catheter of claim 1 , further comprising one or more intermediate layers disposed between the inner and outer polymeric layers.

3. The catheter of claim 1 , further comprising a reinforcing layer disposed between the inner polymeric layer and the outer polymeric layer.

4. The catheter of claim 1 , further comprising a reinforcing layer and an intermediate layer disposed between the inner polymeric layer and the outer polymeric layer.

5. The catheter of claim 1, wherein the amount of PTFE in the blend is from 1% to 35% by weight of the total blend.

6. The catheter of claim 1, wherein the amount of PTFE in the blend is between 5% and 15% by weight of the total blend.

7. The catheter of claim 1, wherein the amount of PTFE in the blend is from 0.5% to 25% by weight of the total blend.

8. The catheter of claim 1 , wherein the one or more copolymers include a copolymer having greater than 5% TFE monomer.

9. The catheter of claim 1 , wherein the one or more copolymers include a copolymer having from 10% to about 40% TFE monomer.

10. The catheter of claim 1 , wherein the one or more copolymers include PFA, FEP, ETFE, EFEP, and THV.

11. The catheter of claim 1 , wherein the blend further comprises a liquid lubricant.

12. The catheter of claim 11, wherein the liquid lubricant is present in the blend at 2% to 5% by weight.

13. The catheter of claim 11 , wherein the liquid lubricant comprises one or more of TFEO and HFPO.

14. The catheter of claim 1 , wherein the shaft comprises one or more catheter shaft sections.

15. 1. A catheter liner comprising: The catheter liner comprises: an inner polymeric layer disposed adjacent to the outer polymeric layer and defining an inner lumen; the inner polymer layer comprises a blend of two or more polymers; The blend of two or more polymers comprises PTFE and one or more copolymers. Catheter liner.

16. 16. The catheter liner of claim 15, wherein the amount of PTFE in the blend is from 1% to 35% by weight of the total blend.

17. 16. The catheter liner of claim 15, wherein the amount of PTFE in the blend is from 5% to 15% by weight of the total blend.

18. 16. The catheter liner of claim 15, wherein the amount of PTFE in the blend is from 0.5% to 25% by weight of the total blend.

19. 16. The catheter liner of claim 15, wherein the one or more copolymers include a copolymer having greater than 5% TFE monomer.

20. 1. A method of manufacturing a catheter liner, comprising: melt blending sufficient PTFE fine powder with a TFE-containing copolymer to form a dispersed blend; melt extruding the dispersed blend to form an inner layer; chemically etching the inner layer to form a chemically activated inner layer; contacting the activated inner layer with at least one additional layer; Equipped with The method wherein the amount of PTFE in said dispersed blend is from 1% to 35% by weight of said total blend.

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