Sheath tube and preparation method thereof

Abstract

The invention relates to a sheath tube and a sheath tube preparation method. The preparation method of the sheath tube comprises the steps of attaching the connecting layer to at least part of the tube wall of the tube body, enabling the connecting layer to wrap at least part of the tube wall, then attaching the hydrophilic layer to at least part of the tube wall attached with the connecting layer, and enabling the hydrophilic layer to wrap at least part of the connecting layer. Therefore, the sheath tube can be prepared by more easily combining the tube body with the hydrophilic layer through the connecting layer. Therefore, the structure of the sheathing canal is simplified, an ultra-thin polytetrafluoroethylene tube does not need to be sleeved inside and outside the canal body, the preparation process of the sheathing canal is simplified, and the manufacturing cost of the sheathing canal is saved. In addition, compared with a sheathing canal in the prior art, at least part of the inner wall and at least part of the outer wall of the sheathing canal are provided with the hydrophilic layers, the sheathing canal can reach a preset position more smoothly during an operation, and tissue of a patient is prevented from being damaged.

Description

Technical Field

[0001] The present application relates to the technical field of medical devices, and in particular to a sheath tube and a preparation method thereof. Background Art

[0002] In the past few decades, minimally invasive interventional surgery has developed rapidly. Compared with open surgical surgery, minimally invasive interventional surgery only requires a smaller incision on the patient to establish a channel with minimal trauma, and use guiding devices such as sheaths to deliver medical device implants or drugs through the channel to the lesion site, so that physical, mechanical or chemical treatment can be performed. Polytetrafluoroethylene (PTFE) and polyvinyl pyrrolidone (PVP) are currently widely used in the preparation of sheaths due to their unique properties and good biosafety. For example, polytetrafluoroethylene can be used for the inner wall of the sheath to achieve a smooth inner wall to facilitate the passage of other components or other instruments; polyvinyl pyrrolidone has good hydrophilic and water absorption properties. When wetted in a water environment, it exhibits excellent lubricity on the surface of the sheath, which facilitates the sheath to better pass through the vascular cavity or natural cavity and smoothly reach the predetermined position, thereby avoiding damage to the tissue.

[0003] In order to achieve low friction and smooth performance on the inner wall of the tube, the sheath products on the market basically use an extra layer of ultra-thin polytetrafluoroethylene tube (PTFE tube) inside the tube to achieve its performance requirements by using the low friction performance of the material. However, due to the complex preparation process of ultra-thin PTFE tube (single-side wall thickness less than 0.05mm) and poor affinity with other materials, in order to achieve a firm fit with other materials, it must undergo surface chemical etching, and the stability of the process is difficult to achieve; at the same time, the fusion process of PTFE ultra-thin tube on the inner wall of other tubes is complicated, and high-cost auxiliary materials such as heat shrink tubes are required. Due to the high prices of PTFE ultra-thin tubes and heat shrink tubes, the use of this material in products greatly increases the cost of the product. In addition, since the sheath is very small, there is a lack of coating technology for the inner wall of the tube. The existing ultra-slip hydrophilic coating that has been maturely used on medical sheaths is only limited to the outer surface of the sheath and cannot be used on the inner surface of the tube. Summary of the invention

[0004] Based on this, it is necessary to provide a sheath tube and a method for preparing the sheath tube in order to overcome the above-mentioned deficiencies in existing sheath tube products and reduce the processing cost of the sheath tube.

[0005] According to one aspect of the present application, a sheath tube is provided, comprising:

[0006] tube body;

[0007] A connecting layer, attached to the tube wall of the tube body, so that the tube wall is wrapped in the connecting layer;

[0008] The hydrophilic layer is attached to the surface of the connecting layer so that the connecting layer is wrapped in the hydrophilic layer.

[0009] In one of the embodiments, the tube wall of the tube body has at least one gap connecting the inner cavity of the tube body and the outside of the tube body, and the gap is filled with the connecting layer.

[0010] In one embodiment, the connecting layer is attached to both the outer wall and the inner wall of the tube body.

[0011] In one embodiment, the tube body is in a spiral structure, a mesh structure, or a common structure of the two extending along its own axial direction.

[0012] In one embodiment, the material of the connecting layer is one or more of polyamide, polyetheramide, polyurethane, polyethylene or polypropylene;

[0013] And / or, the material of the hydrophilic layer is one or more of hyaluronic acid, polyvinyl pyrrolidone, polyvinyl alcohol, polyethylene glycol or polyacrylamide.

[0014] In one embodiment, the wall thickness of the tube body after being wrapped by the connecting layer is 0.1 mm to 0.3 mm;

[0015] And / or, the thickness of the hydrophilic layer is 0.01 mm to 0.1 mm.

[0016] According to another aspect of the present application, there is provided a method for preparing the sheath tube as described above, comprising:

[0017] S1. attaching a connection layer to at least a portion of the tube wall of the tube body, so that the connection layer wraps the tube wall;

[0018] S2. Attaching a hydrophilic layer on the connecting layer.

[0019] In one embodiment, step S1 comprises:

[0020] S11, immersing at least a portion of the tube body into a first solution, so that at least a portion of the tube body is adhered to the first solution;

[0021] S12, taking out the tube body from the first solution;

[0022] S13, solidifying the first solution attached to the tube body to form the connecting layer.

[0023] In one embodiment, step S11 includes:

[0024] S111, immersing the tube body into the first solution at a uniform speed;

[0025] And / or, step S12 includes:

[0026] S121, taking out the tube body from the first solution at a uniform speed.

[0027] In one embodiment, step S2 comprises:

[0028] S21, immersing at least part of the connection layer into a second solution, so that the second solution adheres to the connection layer;

[0029] S22, taking out the tube body from the second solution;

[0030] S23, solidifying the second solution attached to the surface of the connecting layer to form the hydrophilic layer.

[0031] In one embodiment, step S21 includes:

[0032] S211, immersing the tube body into the second solution at a uniform speed;

[0033] And / or, step S22 includes:

[0034] S221, taking out the tube body with the connecting layer attached thereto from the second solution at a uniform speed.

[0035] In one embodiment, after step S2, the method further includes:

[0036] S3, cutting off the portion of the tube body to which the connecting layer is not attached.

[0037] The above sheath tube and its preparation method, by attaching a connecting layer to at least part of the tube wall of the tube body, so that the connecting layer wraps at least part of the tube wall in the form of a film, and at the same time, by directly attaching a hydrophilic layer for making the sheath tube exhibit better lubricity on the surface of the connecting layer, the hydrophilic layer also directly wraps at least part of the connecting layer in the form of a film, so that the tube body can be more easily combined with the hydrophilic layer through the connecting layer to prepare the sheath tube, thereby simplifying the structure of the sheath tube, and there is no need to arrange an ultra-thin polytetrafluoroethylene tube inside and outside the tube body, thereby simplifying the preparation process of the sheath tube and saving the manufacturing cost of the sheath tube. In addition, compared with the sheath tube of the prior art, at least part of the inner wall and at least part of the outer wall of the sheath tube have a hydrophilic layer, which can more smoothly reach the predetermined position during surgery to avoid damage to the patient's tissue. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A front view of a sheath provided in accordance with an embodiment of the present application.

[0039] Figure 2 A cross-sectional view of a tube body provided in an embodiment of the present application having a connecting layer and a hydrophilic layer attached thereto.

[0040] Figure 3 for Figure 2 Schematic diagram of the enlarged H region.

[0041] Figure 4 A front view of a tube body with a spiral structure provided in one embodiment of the present application.

[0042] Figure 5 A front view of a tube body with a mesh structure provided in one embodiment of the present application.

[0043] Figure 6 A flowchart of a method for preparing a sheath tube according to an embodiment of the present application.

[0044] Figure 7 It is a schematic diagram of the steps of the sheath preparation method when the tube body is a mesh structure.

[0045] Figure 8 It is a schematic diagram of the steps of the method for preparing the sheath tube when the tube body has a spiral structure.

[0046] Description of reference numerals:

[0047] 10. sheath; 100. tube body; 101. gap; 200. connecting layer; 300. hydrophilic layer; 310. outer hydrophilic layer; 320. inner hydrophilic layer; 40. first solution; 50. second solution. DETAILED DESCRIPTION

[0048] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0049] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0050] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0051] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0052] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0053] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0054] As described in the background technology, a sheath is a guiding device that delivers medical device implants or drugs through the channel to the lesion site for physical, mechanical or chemical treatment during minimally invasive surgery. In order to achieve low friction and smooth performance of the inner wall of the sheath, polytetrafluoroethylene (PTFE) and polyvinyl pyrrolidone (PVP) are currently widely used in the preparation of sheaths due to their respective unique properties and good biosafety.

[0055] However, if the above materials are used in the preparation of sheath tubes, it is necessary to add an extra layer of ultra-thin polytetrafluoroethylene tube (PTFE tube) inside the tube, and use the low friction system of the material to achieve its performance requirements. However, due to the complex preparation process of ultra-thin PTFE tubes (single-side wall thickness less than 0.05 mm) and poor affinity with other materials, in order to achieve a firm fit with other materials, surface chemical etching must be performed, and the stability of the process is difficult to achieve; at the same time, the fusion process of PTFE ultra-thin tubes on the inner wall of other tubes is complicated, and high-cost auxiliary materials such as heat shrink tubes are required. Due to the high prices of PTFE ultra-thin tubes and heat shrink tubes, the use of this material in products greatly increases the cost of the product. In addition, since the sheath tube is very small, there is a lack of coating technology for the inner wall of the tube. The existing ultra-slip hydrophilic coating that has been maturely used on medical sheath tubes is only limited to the outer surface of the sheath tube and cannot be used on the inner surface of the tube.

[0056] Based on the above problems, the inventors of the present application have thought of immersing a tube body with certain elasticity and flexibility in a solution dissolved with other special materials so that two or more layers of thin film coating can be formed on the surface of the tube body to wrap the tube wall. In this way, there is no need to add an additional layer of ultra-thin polytetrafluoroethylene tube, so that the tube wall of the tube body can be directly attached with a coating that is used to make the sheath tube exhibit better torque control performance and better lubricity, thereby reducing many process steps in the preparation of the sheath tube, thereby simplifying the preparation process of the sheath tube, effectively saving the manufacturing cost of the sheath tube and solving the above problems.

[0057] The structure of the sheath tube and the method for preparing the sheath tube in the present application are described below by taking a medical sheath tube used in minimally invasive surgery as an example. It is understood that in other embodiments, the sheath tube of the present application is not limited to a medical sheath tube, but can also be a catheter used in any other field, which is not limited here.

[0058] See also Figure 1 , Figure 1The schematic diagram of the structure of the sheath tube 10 in one embodiment of the present application is shown. The sheath tube 10 provided in one embodiment of the present application comprises a tube body 100, a connecting layer 200 and a hydrophilic layer 300, wherein the connecting layer 200 is attached to at least a portion of the tube wall of the tube body 100, so that at least a portion of the tube wall is wrapped in the connecting layer 200; the hydrophilic layer 300 is attached to at least a portion of the outer surface of the connecting layer 200, so that at least a portion of the connecting layer 200 is wrapped in the hydrophilic layer 300. The connecting layer 200 is used to provide an intermediary effect for the connection between the tube body 100 and the hydrophilic layer 200, so that the tube body 100 and the hydrophilic layer 200 can be more easily combined with each other, and the connecting layer 200 is also used to support and reinforce the tube body 100, and the hydrophilic layer 300 is used to make the sheath tube 10 exhibit better lubricity and reduce friction, so that the sheath tube 10 can better pass through the vascular cavity or natural cavity, so that it can smoothly reach the predetermined position, thereby avoiding damage to the tissue in the patient's body.

[0059] Specifically, the tube body 100 needs to have strong mechanical properties such as pushing and twisting control, so as to achieve expansion or bending deformation. In some embodiments, the tube body 100 may be a tube body 100 with a solid structure, such as a solid tube body 100 with certain elasticity and flexibility, or a skeleton structure with a gap 101. Figure 2 and Figure 3 As shown, the tube body 100 is a skeleton structure with a gap 101, and the gap 101 connects the inner cavity of the tube body 100 and the outside of the tube body 100. In some cases, it is not easy for the hydrophilic layer 300 to be directly attached to the surface of the tube body 100. If it is necessary to directly attach to the surface of the tube body 100, it must be achieved by spraying or adding a layer of ultra-thin polytetrafluoroethylene tube (PTFE tube) and other processes, which makes the preparation process of the sheath tube complicated and difficult to achieve. Therefore, as a preferred embodiment, the connecting layer 200 is filled in the gap 101, so that the connecting layer 200 wraps the tube body 100, that is, the connecting layer 200 is attached to the inner wall and the outer wall of the tube body 100, and the hydrophilic layer 300 is attached to the surface of the connecting layer 200, including an outer hydrophilic layer 310 and an inner hydrophilic layer 320, wherein the outer hydrophilic layer 310 is attached to the surface of the connecting layer 200 located outside the tube body 100, and the inner hydrophilic layer 320 is attached to the surface of the connecting layer 200 located inside the tube body 100, so that the hydrophilic layer 300 is directly attached to the surface of the connecting layer 200.

[0060] Thus, through the above arrangement, during the preparation process of the sheath tube, the connecting layer 200 serves as a substrate for attaching the hydrophilic layer 300 to the tube body 100, which can make it easier for the tube body 100 to be combined with the hydrophilic layer 300, and can provide support and reinforcement for the skeleton structure tube body 100 having the gap 101, so that the tube body 100 has better strength and rigidity, and thus the tube body 100 has better twist control, pushing and support. In addition, the hydrophilic layer 300 makes the inner and outer surfaces of the sheath tube 10 have better lubrication properties, and simplifies the structure of the sheath tube 10.

[0061] Furthermore, the tube body 100 of the skeleton structure can be implemented in various ways. In one implementation, Figure 4 As shown, the tube body 100 is a spiral structure extending along its own axial direction, and is formed by spirally winding a metal wire. The size of its pitch is the size of the above-mentioned gap 101. The spiral structure is used to enhance the flexibility and bending resistance of the tube body 100, or as shown in FIG. Figure 5 As shown, the tube body 100 is a mesh structure, woven from metal wires, and can also be formed by punching holes on the tube wall of the tube body 100 through processes such as laser cutting to increase the pushing ability and torsional resistance of the tube body 100, which is not particularly limited here.

[0062] Specifically, when the tube body 100 is wound or woven by metal wires, the material of the metal wires can be stainless steel or nickel-titanium metal, so that the tube body 100 has better pushing and twisting control performance, can perform arbitrarily expansion or bending deformation under the action of external force, and can eliminate the deformation after deformation and return to its original shape.

[0063] In some embodiments, the metal wire can be a round wire or a flat wire. Preferably, when the metal wire is a round wire, the size of the round wire is in the range of 0.01 mm to 0.1 mm; when the metal wire is a flat wire, the thickness of the flat wire is in the range of 0.01 mm to 0.1 mm, and the width is in the range of 0.1 mm to 0.5 mm. When the tube body 100 is wound by metal wires to form a spring-like structure, the spacing between adjacent metal wires is 0.1 mm to 2 mm; when the tube body 100 is woven by metal wires to form a mesh structure, the PPT (i.e., mesh density) of the mesh structure is in the range of 25 to 100.

[0064] In this way, by adopting the above structural dimension parameters, the mechanical properties of the tube body 100 can be optimized.

[0065] Furthermore, in some embodiments, in order to better combine the connection layer 200 with the metal tube body 100, the material of the connection layer 200 is one of high molecular polymers such as polyamide (PA), polyetheramide (Pebax), polyurethane (PU), polyethylene (PE) or polypropylene (PP) or a mixture thereof, or other types of high molecular polymers. Preferably, the wall thickness of the tube body 100 after being wrapped by the high molecular polymer connection layer 200 is 0.1 mm to 0.3 mm.

[0066] In this way, by utilizing the property that polymers and metals can better combine, the polymer is filled in the gap 101 of the tube body 100 and wraps at least a portion of the tube wall of the tube body 100, which not only further promotes the mutual bonding between the tube body 100 and the hydrophilic layer 300, making it easier for the tube body 100 and the hydrophilic layer 300 to combine with each other, but also improves the bonding strength between the various layers of the sheath 10.

[0067] Furthermore, in order to make the hydrophilic layer 300 have better lubricity and accelerate the curing of the hydrophilic layer 300 during the preparation of the sheath tube 10, in some embodiments, the material of the hydrophilic layer 300 is a polymer such as hyaluronic acid (Hyaluronic Acid), polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA), polyethylene glycol (PEG) or polyacrylamide (PAM) or a mixture thereof. Preferably, the thickness of the hydrophilic layer is 0.01 mm to 0.1 mm.

[0068] Thus, by using the above-mentioned material as the hydrophilic layer 300, the viscous hydrophilic layer 300 can be heated during the preparation of the sheath tube 10, so that the viscous hydrophilic layer 300 can be quickly solidified under the action of heat energy. Thus, the outer wall and the inner wall of the sheath tube 10 can be coated with the hydrophilic layer 300, so that the sheath tube 10 can reach the predetermined position more smoothly during surgery, avoiding damage to the patient's tissue.

[0069] The following, combined with Figures 6 to 8 , a method for preparing the sheath tube 10 of the above structure is introduced.

[0070] In the first step S1, a connection layer 200 is attached to at least a portion of the tube wall of the tube body 100, so that the connection layer 200 wraps the tube wall. Preferably, the connection layer is attached to both the outer wall and the inner wall of the tube body.

[0071] Specifically, Figure 7 and Figure 8 As shown, this step is specifically completed by the following steps. First, the spiral extension (see Figure 7 ) or reticular (cf. Figure 8) The tube body 100 is immersed in the viscous first solution 40, so that the first solution 40 adheres to at least a portion of the tube body 100 and fills the gaps in the tube body 100. Preferably, the tube body 100 is immersed in the first solution 40 at a constant rate. Section A shown in the figure is the immersion section.

[0072] Then, the tube body 100 immersed in the first solution 40 is taken out from the first solution 40. At this time, the immersed section A of the tube body 100 is attached with the first solution 40, and the viscous first solution 40 fills the gap 101 of the section A of the tube body 100. The first solution 40 can be a polyurethane solution, or a polyamide, polyetheramide, polyethylene or polypropylene solution or a mixed solution thereof. Preferably, the tube body 100 immersed in the first solution 40 can be taken out from the first solution 40 at a constant speed. Exemplarily, the speed is preferably 10 mm / min to 100 mm / min. When the tube body 100 immersed in the first solution 40 is taken out from the first solution 40 within this speed range, the thickness of the first solution 40 attached to the section A of the tube body 100 can be relatively uniform, and the phenomenon of the first solution 40 attached to a certain section of the tube body being too thick or too thin will not occur. Furthermore, the thickness of the first solution 40 attached to the section A of the tube body 100 can be controlled by controlling the pulling rate of the tube body 100 .

[0073] Finally, the first solution 40 attached to the tube body 100 is cured to form the connection layer 200. In this step, the first solution 40 on the tube body 100 can be cured by air drying or by using heat or other energy. After curing, the first solution 40 attached to the tube body 100 forms a thin film that wraps the tube body 100A section, and the thin film is the connection layer 200.

[0074] It is understandable that when the tube wall of the tube body 100 is a solid structure or the tube body 100 as a whole is a solid structure, the above-mentioned impregnation method can also be used to make the connection layer 200 adhere to the tube wall of the tube body 100.

[0075] In the second step S2 , the hydrophilic layer 300 is attached to the connecting layer 200 , so that the hydrophilic layer 300 wraps at least a portion of the connecting layer 200 to obtain the sheath tube 10 .

[0076] Specifically, the specific implementation steps of this step are similar to the specific implementation steps of the first step S1. First, Figure 7 and Figure 8 As shown, the connecting layer 200 is at least partially immersed in the second solution 50, preferably at a uniform speed, so that the second solution 50 is attached to at least part of the outer surface of the connecting layer 200. Section B shown in the figure is the immersion section.

[0077] Then, the tube body 100 is taken out from the second solution 50, and the second solution 50 is attached to the B section of the surface of the connecting layer 200. The second solution 50 can be a polymer solution such as a hyaluronic acid solution, a polyvinyl pyrrolidone solution, a polyvinyl alcohol solution, a polyethylene glycol solution or a polyacrylamide solution, or a mixed solution thereof. Also preferably, the tube body 100 attached with the connecting layer 200 can be taken out from the second solution 50 at a constant rate (for example, at the same rate as the above-mentioned removal from the first solution 40) at a uniform speed, so that the thickness of the second solution 50 attached to the B section of the connecting layer 200 can be more uniform. Furthermore, the thickness of the second solution 50 attached to the B section can also be controlled by controlling the pulling rate of the tube body 100.

[0078] Finally, the second solution 50 attached to the connecting layer 200 is solidified to form the hydrophilic layer 300. In this step, the second solution 50 on the connecting layer 200 can also be solidified by air drying, baking or other energy methods. After solidification, the second solution 50 attached to the connecting layer 200 forms a thin film that wraps the B segment of the connecting layer 200, and the thin film is the hydrophilic layer 300.

[0079] In the third step S3, after curing the hydrophilic layer 300, the portion of the tube body to which the connecting layer 200 is not attached is cut off, thereby obtaining the sheath tube 10 structure described in the above embodiment of the present application.

[0080] Furthermore, by controlling the concentration of the first solution 40 and the second solution 50, the thickness of the connecting layer 200 and the hydrophilic layer 300 can also be controlled. Preferably, when the concentration of the first solution 40 and the second solution 50 is 10 mg / ml to 100 mg / ml, the thickness of the connecting layer 200 and the hydrophilic layer 300 can be the thickness described in the above preferred embodiment. It can be seen that the sheath tube 10 is prepared by the above process method, and the filling of the gap 101 of the tube body 100 is completed at one time by dipping, and the connecting layer 200 of the polymer material is formed on the inner and outer surfaces of the tube body 100, so that the tube wall of the tube body 100 is wrapped, so that the inner wall and the outer wall of the tube body 100 are attached with the connecting layer 200. The traditional preparation process requires the use of an extruder to extrude a polymer thin-walled tube in advance, and then the polymer thin-walled tube is combined with the metal tube body 100 by heat bonding or etching. Therefore, compared with the preparation process provided by the present application, the traditional preparation process method is not only complicated in preparation process, but also has high cost of auxiliary materials in the preparation process. The process method provided in the present application for preparing the sheath tube 10 solves the defects existing in the traditional preparation process method, and the connecting layer 200 attached to the tube body 100 also provides a physical surface for coating the hydrophilic layer 300.

[0081] Furthermore, since the hydrophilic coating material used in the existing sheath tube 10 is mostly polyvinyl pyrrolidone, the hydrophilic coating of this material must be cured by UV curing. For the vast majority of tube bodies 100 that are opaque, it is only limited to the outer surface of the tube body 100 and cannot be used on the inner surface of the tube body 100. At the same time, for transparent tube bodies 100, there is a certain loss in the intensity of ultraviolet light when passing through the tube wall, and the curing efficiency is low. When the sheath tube 10 is prepared by the above-mentioned process, the hydrophilic layer 300 is also formed on the surface of the connecting layer 200 in the form of a thin film by dipping, and at least a portion of the connecting layer 200 is also wrapped. Since the hydrophilic layer 300 of the sheath tube 10 provided in the present application can be made of hyaluronic acid, after the hydrophilic layer 300 is coated on at least a portion of the surface of the connecting layer 200, the hydrophilic layer 300 coated on the inner wall of the tube body 100 and the outer wall of the tube body 100 coated with the connecting layer 200 can be cured under the action of heat energy by utilizing the property of hyaluronic acid that can be solidified by heat, thereby overcoming the problem that the ultraviolet light cannot reach the inner wall of the tube body 100 and the hydrophilic layer 300 cannot be effectively cured.

[0082] It should be noted that in the above-mentioned sheath preparation method, all parts of the sheath 10 are not limited to obtaining the connection layer 200 and the hydrophilic layer 300 by the above-mentioned dipping method. The connection layer 200 and the hydrophilic layer 300 can also be attached to part of the surface of the tube body 100 by the above-mentioned dipping method, and the connection layer 200 and the hydrophilic layer 300 are attached to the other surface by conventional process methods, that is, the extruded polymer tube is attached to the tube wall of the tube body 100 to form the connection layer 200, and then the hydrophilic material tube is coated on the surface of the connection layer 200 to form the hydrophilic layer 300. There is no special limitation. However, it is obvious that the best technical effect can be achieved by first immersing the entire tube body 100 in the polymer solution, and then immersing it in the solution of the hydrophilic material to solidify in sequence to form the connection layer 200 and the hydrophilic layer 300.

[0083] Finally, it should be noted that the various technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the various technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0084] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A sheath tube, characterized in that: include: tube body; A connecting layer, attached to the tube wall of the tube body, so that the tube wall is wrapped in the connecting layer; The hydrophilic layer is attached to the surface of the connecting layer so that the connecting layer is wrapped in the hydrophilic layer.

2. The sheath tube according to claim 1, characterized in that: The tube wall of the tube body has at least one gap connecting the inner cavity of the tube body and the outside of the tube body, and the gap is filled with the connecting layer.

3. The sheath tube according to claim 1, characterized in that: The connecting layer is attached to both the outer wall and the inner wall of the tube body.

4. The sheath tube according to claim 1, characterized in that: The tube body is in a spiral structure, a mesh structure or a common structure of the two extending along its own axial direction.

5. The sheath tube according to claim 1, characterized in that: The material of the connecting layer is one or more of polyamide, polyetheramide, polyurethane, polyethylene or polypropylene; And / or, the material of the hydrophilic layer is one or more of hyaluronic acid, polyvinyl pyrrolidone, polyvinyl alcohol, polyethylene glycol or polyacrylamide.

6. The sheath tube according to claim 1, characterized in that: The wall thickness of the tube body after being wrapped by the connecting layer is 0.1 mm to 0.3 mm; And / or, the thickness of the hydrophilic layer is 0.01 mm to 0.1 mm.

7. A method for preparing a sheath tube according to any one of claims 1 to 6, characterized in that: include: S1. attaching a connection layer to at least a portion of the tube wall of the tube body, so that the connection layer wraps the tube wall; S2. Attaching a hydrophilic layer on the connecting layer.

8. The preparation method according to claim 7, characterized in that: Step S1 includes: S11, immersing at least a portion of the tube body into a first solution, so that at least a portion of the tube body is adhered to the first solution; S12, taking out the tube body from the first solution; S13, solidifying the first solution attached to the tube body to form the connecting layer.

9. The preparation method according to claim 8, characterized in that: Step S11 includes: S111, immersing the tube body into the first solution at a uniform speed; And / or, step S12 includes: S121, taking out the tube body from the first solution at a uniform speed.

10. The preparation method according to any one of claims 7 to 9, characterized in that: Step S2 includes: S21, immersing at least part of the connection layer into a second solution, so that the second solution adheres to the connection layer; S22, taking out the tube body from the second solution; S23, solidifying the second solution attached to the surface of the connecting layer to form the hydrophilic layer.

11. The preparation method according to claim 10, characterized in that: Step S21 includes: S211, immersing the tube body into the second solution at a uniform speed; And / or, step S22 includes: S221, taking out the tube body with the connecting layer attached thereto from the second solution at a uniform speed.

12. The preparation method according to claim 7, characterized in that: After step S2, the method further includes: S3, cutting off the portion of the tube body to which the connecting layer is not attached.

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