Catheter with press-fit polytetrafluoroethylene liner and method of manufacture
By combining the PTFE liner with metal tubes with primer and annealing, the problem of lining delamination when the catheter is bent or bent is solved, and the lubricity and mechanical properties of the catheter are improved, making it suitable for medical surgery.
Patent Information
- Application Number
- CN202380057076.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-07-26
- Filing Date
- 2023-07-24
- Publication Date
- 2025-03-28
AI Technical Summary
The PTFE lining of existing catheters is prone to delamination when bending or bending, and its lubricity and mechanical properties are insufficient to meet the needs of medical surgery.
The PTFE liner is pressed onto the metal tube by using a primer and secured to the outer member by annealing, ensuring that the liner is not layered when bent or bent.
The stable fixation of the PTFE lining is achieved, ensuring that the catheter is not layered when bent or bent, and at the same time, the lubricity and mechanical properties of the catheter are improved, and it is suitable for various medical procedures.
Smart Images
Figure CN119731012A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a method and a polytetrafluoroethylene (PTFE) liner pressed onto a metal surface using a primer solution. In particular, the present invention relates to securing a polytetrafluoroethylene liner to a metal pipe to form a conduit. Background Art
[0002] Vascular treatments utilize minimally invasive, catheter-based procedures and specialized equipment and techniques. Catheters used in these procedures often utilize a coating or lining on the inner wall to provide a smooth inner surface. The smooth inner diameter (ID) associated with these devices facilitates reduced friction as devices such as stents, balloons, atherectomies, or thrombectomies are pushed through the lumen of the catheter. If the lubricity of the inner diameter (ID) of the catheter is insufficient, the device may cause damage to the lining as it is pushed through the lumen of the catheter. The effect of increasing the lubricity of the catheter ID is a reduction in the deployment force of the catheter device as it passes through the lumen, thereby increasing the likelihood of a successful procedure.
[0003] The mechanical properties of the catheter liner are also important. For example, high tensile strength and yield strength may be required when certain devices are passed through the catheter in a compressed state. The compressed state exerts an outward radial force, which causes friction with the ID, generally making it difficult to deliver the device therethrough. On the other hand, when the catheter must pass through a vasculature containing sharp turns, high flexibility of the liner is generally required. In this case, a highly flexible liner with moderate tensile strength is generally more desirable than a high tensile strength liner with low flexibility / high stiffness.
[0004] Various materials have been attempted as the inner wall (base lining) material. One material that has been considered is polytetrafluoroethylene (PTFE). PTFE is beneficial because it has many beneficial properties, including excellent chemical resistance, high temperature resistance, biocompatibility, and very low coefficient of friction / high lubricity.
[0005] Known polytetrafluoroethylene based materials used in catheter applications have various disadvantages. For example, although some extruded polytetrafluoroethylene tubes can be produced with sufficiently thin walls and sufficiently high tensile strength, they exhibit high stiffness and high tensile modulus values, making them unsuitable. In addition, it is reported that although modified extruded polytetrafluoroethylene tubes have high tensile strength, the stiffness is not ideal, which is due to the method by which the high tensile strength is obtained. Alternatively, dip-coated tubes generally have relatively low wear resistance, so the IDs of these tubes generally have poor lubricity.
[0006] It would be beneficial to provide a polytetrafluoroethylene liner for metal or rigid pipe that provides the desired strength and lubricity characteristics. It would also be beneficial to provide a method of press-fitting a polytetrafluoroethylene liner to a metal pipe. Summary of the invention
[0007] An object is to provide a metal sheet or tube having a polytetrafluoroethylene liner that is press-fitted to the metal sheet or tube to allow the metal sheet or tube to be bent or flexed without delamination of the polytetrafluoroethylene liner.
[0008] The object is to provide a method of manufacturing a conduit which ensures that the polytetrafluoroethylene liner will remain pressed to the metal sheet or tube when the metal sheet or tube is bent or flexed.
[0009] An object is to provide a catheter having a polytetrafluoroethylene liner press-fitted to a metal tube, which allows the catheter to be bent or curved without delamination of the polytetrafluoroethylene liner.
[0010] The embodiment relates to a catheter having an outer member, a primer, and an inner liner pressed to the outer member. The primer is disposed between the outer member and the inner liner and is annealed to fix the inner liner to the outer member.
[0011] An embodiment relates to a method for press-fitting a polytetrafluoroethylene liner to a flexible outer member. The method includes: applying a primer to an outer surface of the polytetrafluoroethylene liner; applying a primer to an inner surface of the outer member, the inner surface of the outer member facing the outer surface of the polytetrafluoroethylene liner; annealing the primer on the outer surface and the primer on the inner surface; re-applying the primer to the outer surface and the inner surface; moving the outer surface and the inner surface to engage with each other; applying a force to maintain the engagement of the outer surface and the inner surface; and annealing the re-applied primer to press-fit the outer surface to the inner surface.
[0012] Other features and advantages of the present invention will be apparent from the following more detailed description of illustrative embodiments, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Figure 1 is a perspective view of an illustrative embodiment of a catheter of the present invention.
[0014] Figure 2 yes Figure 1 A perspective view of an illustrative embodiment of an outer member of a catheter.
[0015] Figure 3 yes Figure 1 A perspective view of an illustrative embodiment of an interior lining of a catheter.
[0016] Figure 4 is along Figure 1 An enlarged cross-sectional view taken along line 4-4. DETAILED DESCRIPTION
[0017] The description of the illustrative embodiments according to the principles of the present invention is intended to be read in conjunction with the accompanying drawings, which should be considered as part of the entire written description. In the description of the embodiments of the present invention disclosed herein, any reference to direction or orientation is intended only for convenience of description and is not intended to limit the scope of the present invention in any way. Relative terms such as "lower", "upper", "horizontal", "vertical", "above", "below", "up", "down", "top" and "bottom" and their derivatives (e.g., "horizontally", "downwardly", "upwardly", etc.) should be interpreted as referring to the orientation shown in the figure described or discussed at the time. These relative terms are only used for convenience of description and do not require the device to be constructed or operated in a specific orientation unless so explicitly stated. Terms such as "attachment", "fixation", "connection", "coupling", "interconnection" and similar terms refer to the relationship in which structures are fixed or attached to each other directly or indirectly through intermediate structures, as well as removable or rigid attachments or relationships, unless otherwise explicitly stated.
[0018] like Figures 1 to 4 As shown, the device 10 has an outer flexible member 12 and an inner liner 14. The outer flexible member 12 and the inner liner 14 are fixed to each other by a primer 16 located between the outer flexible member 12 and the liner 14, as shown in FIG. Figure 4 In the illustrative embodiment shown, the outer flexible member 12 and the inner liner 14 are tubular members having circular cross-sectional areas, wherein the device 10 is a catheter 18. However, the outer flexible member 12 and the inner liner 14 may have other configurations, including but not limited to planar configurations.
[0019] exist Figure 2 In the illustrated embodiment, the outer flexible member 12 is a hollow flexible metal member having an inner wall 20 and an outer wall 22. In the illustrated embodiment, the inner wall 20 and the outer wall 22 are solid continuous metal surfaces and are not made of mesh or other perforated materials. The outer flexible member 12 has an inner diameter 24 and an outer diameter 26. The outer flexible member 12 can be, but is not limited to, a laser cut hypotube. In the illustrated embodiment, the outer member 12 of the catheter 18 has an inner diameter 24 between about 1 mm and about 13 mm, an outer diameter 26 between about 1.12 mm and about 15 mm, and a thickness between about 0.06 mm and about 1 mm.
[0020] exist Figure 3In the illustrated embodiment, the inner liner 14 is a hollow flexible liner tube or member having an inner wall 30 and an outer wall 32. In the illustrated embodiment, the inner wall 30 and the outer wall 32 are solid continuous surfaces and are not made of mesh or other perforated materials. The inner liner 14 has an inner diameter 34 and an outer diameter 36. The inner liner 14 can be made of polytetrafluoroethylene (PTFE), but is not limited thereto. The inner liner 14 has high lubricity or a low coefficient of friction, which makes it easy to deploy a medical device (not shown) through the inner liner 14 and the catheter 18. The inner liner 14 also has a high enough tensile strength to avoid puncture or tearing of the liner 14 when the medical device passes through the liner 14. In the illustrated embodiment, the inner liner 14 of the catheter 18 has an inner diameter 34 between about 0.8 mm and about 12.7 mm, an outer diameter 36 between about 1 mm and about 13 mm, and a thickness between about 0.1 mm and about 0.15 mm.
[0021] The primer 16 is a mixture that provides adequate adhesion between the outer wall 32 of the inner liner 14 and the inner wall 20 of the outer member 12. In the illustrated embodiment, the primer 16 of the catheter 18 has a thickness between about 0.012 mm and about 0.1 mm.
[0022] In one illustrative embodiment, the primer 16 includes the following:
[0023] describe Volume Percent Ethanol 20-30 Sterile water 15-25 Dimethylacetamide (DMAC) 1-5 Triethylamine solution 35-65 Multifunctional aziridine crosslinker 1-5
[0024] An example of a triethylamine based solution is Primer 5-017 provided by Coatings2Go. An example of a multifunctional aziridine crosslinker is Crosslinker A provided by Coatings2Go.
[0025] The dimethylacetamide in the primer allows for better control of the viscosity of the primer 16. Additionally, since the primer 16 is reactive and changes over time, the dimethylacetamide allows for an extended pot life or shelf life of the primer 16.
[0026] When mixing primers 16, a new syringe should be used to draw each liquid from its container or a properly cleaned and labeled beaker should be used to prevent cross contamination.
[0027] In an illustrative embodiment, when mixing the primer, ethanol is added first, followed by sterile water, dimethylacetamide, triethylamine-based solution, and multifunctional aziridine crosslinking agent. The triethylamine-based solution and multifunctional aziridine crosslinking agent are slowly or gradually added to the mixture. The mixture is covered and allowed to mix or stir for about 5 to about 7 minutes.
[0028] Before applying the primer 16 to the outer member 12 and the inner liner 14, the surfaces of the outer member 12 and the inner liner 14 must be properly cleaned to remove any loose or oily residue that may prevent adhesion, or residue that may allow the inner liner 14 to easily separate from the outer member 12, resulting in delamination. To ensure that all residue is removed, a combination of detergents, polar and non-polar solvents are used.
[0029] The outer member 12 and the inner liner 14 are placed in a cleaning mixture. An illustrative embodiment of the cleaning mixture includes a 1% sterile aqueous solution and Alconox Powdered PrecisionCleaner mixed with water. An ultrasonic cleaner can be used to clean the outer member 12, the inner liner 14, and the cleaning mixture. After the cleaning cycle is completed, the outer member 12 and the inner liner 14 are exposed to a sterile water rinse, an acetone soak, and an alcohol soak. Alternatively, a 70% to 99% isopropyl alcohol (IPA) solution can be used to clean the inner liner 14.
[0030] After the outer member 12 and liner 14 are properly cleaned and the primer 16 is properly mixed, the polytetrafluoroethylene liner is first pre-coated. In the illustrative embodiment, the liner 14 is cut to a length of about 47 inches to about 49 inches, preferably about 48 inches. The liner 14 is placed on the primer pre-coat mandrel. Then, the outer wall 32 of the liner 14 can be cleaned along the entire length of the liner 14 using a 99% isopropyl alcohol damp cloth. The liner 14 with the primer pre-coat mandrel is allowed to dry for about 5 seconds to about 25 seconds using the distal end 42, preferably about 15 seconds.
[0031] The superabsorbent foam pad is wetted with primer 16. A thin coat of primer 16 is then applied to the outer wall 32 of the liner 14. The coated liner 14 is then air dried for about 8 minutes to about 12 minutes, preferably about 10 minutes. These steps are repeated.
[0032] The pre-coated twice liner 14 is then annealed in an oven for about 5 minutes to about 7 minutes, preferably about 6 minutes, at a temperature of about 155° F. to about 165° F., preferably about 160° F. Once completed, the liner 14 is removed from the oven and cooled in a clean room until it reaches room temperature.
[0033] The distal end 44 of the outer member 12 is also pre-coated. The primer 16 is applied to the distal end 44 to a depth of about 3 inches. The inner wall 20 of the outer member 12 is also wiped from the distal end 44 to smooth and remove excess primer 16. The outer member 12 is allowed to dry for about 10 minutes + / - 1 minute using the distal end 44. These steps are repeated.
[0034] The twice pre-coated outer member 12 is then placed in an oven for annealing for 6 minutes + / - 1 minute at 160° F. + / - 5° F. Once completed, the outer member 12 is removed from the oven and cooled in a clean room until it reaches room temperature.
[0035] After the inner liner 14 and outer member 12 are pre-coated, the catheter 18 is assembled. The liner pull wire is inserted into the distal end 44 of the outer member 12 and pulled until the pull wire exits the proximal end 48 of the outer member 12. The outer member 12 is positioned and retained in the fixture with the proximal end 48 exposed approximately 0.25 inches from the fixture 50.
[0036] The balloon or inflatable core rod is positioned in the inner liner 14, and the inner liner 14 with the inflatable core rod is positioned on the fixed assembly near the outer member. One end of the pull wire is tied to the end of the inner liner 14.
[0037] The inner liner 14 is pulled through the outer member 12. As this occurs, additional primer 16 is applied to the outer wall 32 of the inner liner 14.
[0038] With the inner liner 14 fully inserted into the outer member 12, the pull wire 46 is removed from the inner liner 14. The inflatable mandrel is inflated to apply a force to the inner member 14, causing the outer wall 32 of the inner member 14 to be pushed against the inner wall 20 of the outer member 12. With the inflatable mandrel inflated, the primer 16 is applied to the outer wall 22 of the outer member 12, approximately 0.25 inches from both the proximal end 48 and the distal end 44 of the outer member 12. Excess primer 16 is gently wiped along the entire outer wall 22 of the outer member 12.
[0039] The inner liner 14 and outer member 12 with the inflated inflatable mandrel remain in place for at least about 13 minutes to about 17 minutes, preferably about 15 minutes, to allow the primer 16 to cure. Then, the inflatable mandrel is deflated and removed from the inner liner 14.
[0040] Then, a process or reflow mandrel is inserted into the inner liner 14. The inner liner 14 and outer member 12 (with the process mandrel positioned therein) are moved into an oven that has been preheated to a temperature of 430°F. The temperature is set to 420°F and the inner liner 14 and outer member 12 are positioned in the oven for about 18 minutes to about 22 minutes, preferably about 20 minutes, to allow the primer 16 to anneal. Once completed, the catheter 18 (with the inner liner 14 properly secured to the outer member 12) is removed from the oven and cooled in a clean room until it reaches room temperature.
[0041] After the primer 16 has been properly annealed and the inner liner 14 has been secured to the outer member 12, any excess primer 16 is removed from the outer wall 22 of the outer member 12. The process mandrel is removed. The inner liner 14 is trimmed to allow the inner liner 14 to extend approximately 0.5 inches beyond the proximal end 48 of the outer member 12. The portion of the inner liner 14 extending beyond the proximal end 48 is flared and folded over the proximal end 48, as shown in FIG. Figure 1 shown.
[0042] The catheter 18 made using the outer member 12, the inner liner 14, and the primer 16 allows the inner liner 14 to have an optimal inner diameter 34 while minimizing the outer diameter 26 of the outer member 12. The use of the primer 16 prevents the inner liner 14 from delaminating from the outer member 12 when the catheter is bent or flexed. The combination of the inner liner 14 having high lubricity and high tensile strength and the outer member 12 having appropriate flexibility and bending properties allows the catheter to be used for a variety of medical devices or procedures, including but not limited to stents, balloons, atherectomy, or thrombectomy.
[0043] Although the present invention has been described with reference to preferred embodiments, it will be appreciated by those skilled in the art that various changes may be made and that equivalents may be substituted for its elements without departing from the spirit and scope of the present invention as defined in the appended claims. It will be appreciated by those skilled in the art that the present invention may be used with many modifications of structure, arrangement, proportion, size, material and components and otherwise used in the practice of the present invention without departing from the principles of the present invention, which modifications are particularly suitable for specific environments and operating requirements. Therefore, the presently disclosed embodiments should be considered in all respects to be illustrative and not restrictive, and the scope of the present invention is defined by the appended claims, rather than by the foregoing description or embodiments.
Claims
1. A method of laminating a polytetrafluoroethylene liner to a flexible outer member, the method comprising: applying a primer to the outer surface of the polytetrafluoroethylene liner; applying the primer to an inner surface of the outer member, the inner surface of the outer member facing the outer surface of the polytetrafluoroethylene liner; annealing the primer on the outer surface and the primer on the inner surface; applying the primer again to the outer surface and the inner surface; moving the outer surface and the inner surface into engagement with each other; applying a force to maintain engagement of the outer surface and the inner surface; as well as The reapplied primer is annealed to press fit the outer surface to the inner surface.
2. The method of claim 1, further comprising: The outer surface and the inner surface are cleaned before applying the primer.
3. The method of claim 1, wherein the flexible outer member is a flexible tube, an inner wall of the flexible tube is the inner surface, and the flexible tube has an inner diameter.
4. The method of claim 3, wherein: The polytetrafluoroethylene liner is a lined pipe, the outer wall of the lined pipe is the outer surface, the lined pipe has an outer diameter, and the outer diameter is substantially equal to but smaller than the inner diameter of the flexible pipe.
5. A method as claimed in claim 4, wherein the outer surface and the inner surface are moved into engagement with each other by an inflatable mandrel which is inserted into the liner pipe and inflated, preferably wherein the inflatable mandrel is removed and a process mandrel is inserted into the liner pipe before annealing the re-applied primer.
6. The method of claim 1, wherein the primer contains dimethylacetamide.
7. The method of claim 6, wherein the primer contains triethylamine, preferably wherein the primer contains a multifunctional aziridine crosslinker.
8. A catheter, comprising: External components; Primer; and an inner liner pressed onto the outer member; The primer is disposed between the outer member and the inner liner and is annealed to secure the inner liner to the outer member.
9. The catheter of claim 8, wherein the outer member is a flexible solid member having an inner wall and an outer wall.
10. The catheter of claim 9, wherein the outer member has an outer diameter of between about 1.12 mm and about 15 mm, preferably wherein the outer member has a thickness of between about 0.06 mm and about 1 mm.
11. The catheter of claim 8, wherein the inner lining comprises polytetrafluoroethylene.
12. The catheter of claim 11, wherein the inner diameter of the inner liner is between about 0.8 mm and about 12.7 mm, preferably wherein the inner liner has a thickness between about 0.1 mm and about 0.15 mm.
13. The catheter of claim 8, wherein the primer has a thickness between about 0.012 mm and about 0.1 mm.
14. The catheter of claim 13, wherein the primer comprises dimethylacetamide.
15. The catheter of claim 14, wherein dimethylacetamide comprises about 1% to about 5% of the total volume of the primer, preferably wherein the primer comprises a crosslinking agent.