WO2020134690A1

WO2020134690A1 - Medical tubing and manufacturing method therefor

Info

Publication number: WO2020134690A1
Application number: PCT/CN2019/118968
Authority: WO
Inventors: 秦明林; 李兆敏; 孙权权; 邓智华; 何光彬; 阙亦云
Original assignee: 脉通医疗科技(嘉兴)有限公司
Priority date: 2018-12-24
Filing date: 2019-11-15
Publication date: 2020-07-02
Also published as: CN111347698A; CN111347698B

Abstract

The present invention provides a medical tubing and a manufacturing method therefor. The manufacturing method comprises: providing an original tubing, which is used as an inner tubing layer; forming an intermediate tubing layer on the outer surface of the inner tubing layer by weaving with metal braids, and forming a macromolecular coating on the surface of the intermediate tubing layer, and the macromolecular coating being used for forming fixed nodes at cross points of the metal braids after being heated and fused; and forming an outer tubing layer on the outer surface of the intermediate tubing layer. In addition, on the basis of the macromolecular coating, no slippage would occur at cross points of the metal braids, so that a torque transmission capability of the medical tubing is improved, the interfacial bond property between the metal braids and the inner and outer tubing layers is improved, and the overall strength of the medical tubing is improved.

Description

Medical tube and its preparation method

Technical field

The invention relates to the technical field of medical equipment, in particular to a medical tube and a preparation method thereof.

Background technique

With the development of microtraumatic interventional therapy technology, the application of medical interventional tubing is becoming more and more extensive. In the process of interventional therapy, the catheter needs to be delivered to the treatment target site safely and effectively. Therefore, interventional therapy has high requirements on the mechanical properties of the catheter, and the most important mechanical properties are torque transmission and flexibility.

In addition, in medical tubing, an enhanced composite tubing has emerged. The reinforced composite pipe has a structure in which the braided net is uniformly dispersed in the center of the pipe wall thickness, which can strengthen the mechanical properties of the pipe. However, the reinforced composite pipe still has some problems, especially the poor torque transmission ability. Therefore, it is necessary to improve the existing composite pipes.

Summary of the invention

The purpose of the present invention is to provide a medical tube and its preparation method to solve the problem of poor torque transmission capability of existing medical tubes.

To achieve the above objective, the present invention proposes a method for preparing medical tubing, which includes the following steps:

Providing an original pipe, and using the original pipe as an inner layer of the pipe;

On the outer surface of the inner layer of the pipe, braided with metal braided wire to form an intermediate layer of the pipe, wherein a polymer coating is formed on the surface of the intermediate layer of the pipe, and the polymer coating is used to melt under heat Forming a fixed node at the intersection of the metal braided wires; and

A tube outer layer is formed on the outer surface of the tube intermediate layer.

Preferably, the polymer coating is applied on the surface of the metal braid before forming the intermediate layer of the pipe.

Preferably, the step of applying the polymer coating on the surface of the metal braid before forming the intermediate layer of the pipe includes:

Dip coating and pulling the metal braided wire at least once in a solution containing a polymer coating material, and curing the metal braided wire after each dip coating and pulling the metal braided wire, In order to obtain the metal braided wire coated with the polymer coating on the surface.

Preferably, the speed of pulling the metal braided wire each time is 5-20 cm/min, and the temperature for curing the metal braided wire is 200-280°C.

Preferably, the outer layer of the pipe is formed on the outer surface of the middle layer of the pipe by an extrusion process, and the polymer coating is heated and melted at an extrusion temperature to form a place at the intersection of the metal braided wires Describe the fixed node.

Preferably, the extrusion temperature of the outer layer of the pipe is 200-270°C.

Preferably, the material of the metal braided wire is selected from one of stainless steel, carbon steel, cast iron, copper, aluminum, nickel, and iron-chromium aluminum alloy.

Preferably, the material of the polymer coating is polymer plastic.

Preferably, the polymer plastic is selected from one or a combination of polyamide, polyether block amide, and thermoplastic polyurethane.

Preferably, the thickness of the polymer coating is 16-57 μm.

Preferably, the thickness of the polymer coating is 16-43 μm.

In addition, in order to achieve the above object, the present invention also proposes a medical tubing, which is prepared by using any of the above medical tubing preparation methods.

Preferably, the wall thickness of the medical tube is 0.01 to 0.015 inch.

In the medical tube and its preparation method provided by the present invention, by forming a polymer coating on the intermediate layer of the tube, the polymer coating can be heated and melted to form a fixed node at the intersection of the metal braided wire, so that each The braided wire cannot slip at the intersection. In this way, the torque transmission performance of the medical tubing can be improved, and the flexibility of the medical tubing can be ensured. At the same time, the polymer coating can be used to improve the interfacial bonding performance between the metal braided wire and the inner and outer tubing bases, thereby improving the overall strength of the medical tubing. In addition, the polymer coating will not have a negative impact on human tissue, ensuring the safety of the product.

In a preferred embodiment, the thickness of the polymer coating is 16-57 μm, which can effectively improve the torque transmission capability of medical tubing. More preferably, the thickness of the polymer coating is 16-43 μm, while improving the torque transmission capacity of the medical tube, and ensuring good flexibility of the medical tube.

In a preferred embodiment, the polymer coating is applied to the metal braid before forming the intermediate layer of the pipe. More preferably, the metal braided wire is dip-coated and pulled at least once in a solution containing a polymer coating material, and after each dip-coating and pulling of the metal braided wire, the metal braided wire is cured to obtain Metal braided wire coated with polymer coating on the surface. In this way, not only the process is simple, environmentally friendly, and convenient for continuous production, but also the polymer coating can be evenly coated on the surface of the metal braided wire, and the torque transmission performance and overall strength of the medical tube are better improved.

BRIEF DESCRIPTION

FIG. 1 is a schematic diagram of a pipe middle layer and a pipe outer layer provided on an inner layer of a pipe successively provided by an embodiment of the present invention.

detailed description

In order to make the purpose, advantages and features of the present invention clearer, the medical tubing and the preparation method of the present invention will be described in detail in conjunction with specific drawings and embodiments. It should be noted that the drawings are in a very simplified form and all use inaccurate scales, which are only used to conveniently and clearly assist the purpose of explaining the embodiments of the present invention.

As used in this specification and the appended claims, the term "or" is generally used with the meaning including "and/or" unless the content clearly indicates otherwise. In addition, in the following description, a large number of specific details are given in order to provide a more thorough understanding of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without one or more of these details. In other embodiments, in order to avoid confusion with the present invention, some technical features known in the art are not described.

Here, the problems in the prior art and the core idea of the present invention will be described specifically. As mentioned above, the inventors found that the existing reinforced composite pipe has a poor torque transmission capability. The inventor further research found that the thinner wall of medical tubing makes metal fibers widely used in medical tubing, because metal fiber can provide higher support strength and ensure the mechanical properties of medical tubing. The inventors further researched and found that in the metal fiber reinforced medical tubing, the braided wires are only physically interlaced (that is, not fixed together), so that each braided wire is prone to slip at the intersection, and the metal fiber The smooth surface makes the braided wires more prone to sliding deformation at the intersection. All of these affect the torque transmission capacity of medical tubing, which is not conducive to doctors performing surgical operations.

Based on the above research, in an embodiment, the present invention provides a method for preparing medical tubing, which includes the following steps:

Step 1: Provide an original pipe and use the original pipe as the inner layer of the pipe;

Step 2: On the outer surface of the inner layer of the pipe, weave with metal braided wire to form an intermediate layer of the pipe, wherein a polymer coating is formed on the surface of the intermediate layer of the pipe, and the polymer coating is used for Heated and melted to form a fixed node at the intersection of metal braided wire;

Step 3: forming a pipe outer layer on the outer surface of the middle layer of the pipe.

In another embodiment, the present invention also provides a medical tube prepared by the above preparation method.

In this way, during the preparation process, when the polymer coating is heated and melted, the melted polymer coating material can form a fixed node at the intersection of each braided wire, so that the braided wire and the braided wire cannot be at the intersection point Sliding (that is, being fixed), thereby improving the torque transmission capacity of the medical tube and ensuring the compliance of the tube. In addition, the polymer coating material makes the inner layer of the tube and the outer layer of the tube more tightly bonded together, which enhances the bonding strength between the inner and outer layers of the tube, thereby improving the overall strength of the medical tube. In addition, the polymer coating will not have a negative impact on human tissue, ensuring the safety of the product.

Next, the medical tube of the present invention and its preparation method will be further described in conjunction with FIG. 1 and specific embodiments.

As shown in FIG. 1, by placing the tube middle layer 2 and the tube outer layer 3 on the tube inner layer 1 in sequence, a medical tube 10 can be obtained, that is, the medical tube 10 includes a sequence from inside to outside along the radial direction of the tube The inner tube layer 1, the middle tube layer 2 and the outer tube layer 3 are arranged. Optionally, the inner diameter of the medical tube 10 is 0.07 to 0.10 inch, the outer diameter is 0.08 to 0.11 inch, and the wall thickness is 0.01 to 0.015 inch. Obviously, the medical tubing 10 of the embodiment of the present invention has a thin wall. To this end, a tube intermediate layer 2 is provided between the tube inner layer 1 and the tube outer layer 3, and the tube inner layer 1 and the tube outer layer 3 are structurally supported by the tube intermediate layer 2, thereby improving the overall strength of the medical tube 10. In practical applications, the intermediate layer 2 of the pipe material is specifically woven from a metal braided wire, and the mesh shape formed by the braiding is preferably a diamond shape. It can be monofilament braided or double filament braided. The weaving method is not limited to pressing one to pick one, pressing two to pick two, etc. Preferably, the metal braided wire is 0.002-0.004 inch round wire or flat wire. Further, the material of the metal braided wire is specifically selected from high temperature resistant metal materials, more specifically selected from metal materials that can withstand the extrusion temperature described below, for example, selected from stainless steel, carbon steel, cast iron, copper, aluminum, nickel and One or a combination of iron-chromium aluminum alloys.

A polymer coating is formed on the tube intermediate layer 2, and the material of the polymer coating is preferably the same as or similar to the material of one of the tube inner layer 1 and the tube outer layer 3, such as the tube inner layer 1 and the tube outer layer The material of one of the 3 materials has a melting point and compatibility close to or the same. Therefore, the material of the polymer coating can be configured according to the material of the inner and outer layers of the pipe, so that the inner and outer layers of the pipe can achieve better adhesion through the polymer coating. Optionally, the material of the polymer coating is a polymer plastic, specifically a polymer plastic with a melting point of 200-240°C. In this embodiment, the material of the polymer coating is specifically selected from one of polyamide (PA) (such as nylon 6: PA6; nylon 12: PA12), polyether block amide (PEBA), and thermoplastic polyurethane (TPU) Or a combination thereof.

In addition, the materials of the inner tube layer 1 and the outer tube layer 3 are selected from biomedical polymer materials with excellent properties, such as thermoplastics. The thermoplastic can be selected from polyether block amide (PEBA), polyethylene (PE), polypropylene (PP), polyamide (PA) (such as nylon 6: PA6; nylon 12: PA12) and thermoplastic polyurethane (TPU) One or a combination of them. Here, the material of the tube outer layer 3 is preferably arranged according to the material of the tube inner layer 1. The material of the outer layer 3 of the pipe is mainly selected from the material with a similar melting point and better compatibility with the inner layer 1 of the pipe. For example, the material of the inner layer 1 of the pipe is polyether block amide, and the material of the outer layer 3 of the pipe is selected to be Nylon 6 or nylon 12 with similar melting points and better compatibility of ether block amide is the best, so that the inner and outer pipe can be better combined.

Further, a polymer coating is formed on the inner surface or outer surface of the tube intermediate layer 2, or a polymer coating is formed on both the inner and outer surfaces, so that the polymer coating can be heated and melted to cross the metal braided wire A fixed node is formed at the point, and the inner and outer layers of tubing are more tightly bonded.

Further, before forming the intermediate layer 2 of the pipe, it is preferable to coat the polymer coating material on each metal braided wire, and then weave the metal braided wire coated with the polymer coating material on the inner layer 1 of the pipe That's it. In this way, not only is the process simple, it is convenient for continuous production, improves the production efficiency, and reduces the production cost, but also allows the polymer coating to be evenly coated on the surface of the metal braided wire, and better improves the torque transmission performance and overall strength of the medical tubing. Specifically, the steps of applying the polymer coating material on the metal braided wire include:

Preparation of solutions containing polymer coating materials;

The metal braided wire is dip-coated and pulled at least once in a solution containing a polymer coating material, and after each dip-coating and pulling of the metal braided wire, the metal braided wire is cured to obtain a surface coated with Polymer coated metal braided wire.

More specifically, before coating, the metal braided wire needs to be fixed. After the braided wire is fixed with a certain tension using a take-up and pay-off machine, the dipping and pulling processes are performed. It includes the following steps:

Immerse the metal braided wire in the dipping tank containing the polymer coating material solution.

Then, at a designated pulling speed, the metal braid impregnated with the polymer coating material is taken out of the dipping tank. Here, the speed of pulling the metal braided wire is preferably 5 to 20 cm/min, and more preferably 5 to 15 cm/min. The faster the pulling speed, the thicker the coating.

Next, the metal braided wire impregnated with the polymer coating material is placed in a sintering furnace for curing treatment, and the curing temperature can be selected from 200 to 280° C. to obtain the metal braided wire coated with the polymer coating material on the surface.

After the metal braided wire coated with the polymer coating material is obtained, the braided metal braided wire coated with the polymer coating material can be braided on the original pipe material using a braiding machine. Here, the original pipe used as the inner layer 1 of the pipe can be obtained by cutting a part of the length from the entire extruded pipe, and the metal braid can be woven on different types of original pipes.

Further, after weaving the metal braided wire coated with the polymer coating material on the original pipe, an extrusion process can be performed, thereby covering the pipe middle layer 2 with a pipe outer layer 3. The extrusion temperature (preferably 200-270°C) is higher than the melting temperature of the polymer coating material, so that the polymer coating can be heated in a molten state at the extrusion temperature, so that the metal braided wire is fixed at the intersection. Therefore, preferably, while extruding the outer layer 3 of the pipe, the polymer coating on the metal braid is heated to be in a molten state, so that the high-point coating fixes the braid of the middle layer of the pipe at the intersection , And form a fixed node, and also make the inner layer 1 of the pipe and the outer layer 3 of the pipe more tightly bonded together. Specifically, the original braided pipe can be fixed with a certain tension using a take-up and pay-off machine, and then a single-screw extruder is used to coat the original braided pipe with a layer of outer tube 3, which is then cooled (may be Water cooling, air cooling) and cutting, to obtain the medical tubing 10 of the required length.

Therefore, when the medical tubing 10 of the present embodiment is twisted, the intersection between the metal braided wires is fixed (not movable) by the polymer coating, so that the metal braided wire cannot slip at the intersection point. It is good for the torque to be transmitted better, so as to improve the torque transmission ability of the medical tubing, and it is conducive to the doctor to perform the operation. The present invention does not specifically limit the application range of the medical tube 10, for example, it can be applied to products such as guide catheters, contrast catheters, radiofrequency ablation catheters, mapping catheters, and stent graft delivery systems, so as to meet the needs of different products. In addition, in practical applications, the polymer coating of the present invention is not limited to being coated on the metal braided wire before forming the tube intermediate layer 2, but can also be coated separately on the metal braided wire after forming the tube intermediate layer 2, specifically coated Cover the intersection of metal braided wire. However, the latter has a limited coating area, which is not convenient for production operations. Therefore, the present invention preferably coats the entire metal braided wire by dipping and pulling, which can overcome the defects of the latter, simplify the process, ensure continuous production, and will not damage the pipe during the curing of the polymer coating Layer 1, to ensure the performance of the pipe. In addition, this process will not cause pollution to the environment, and the environmental protection effect is good.

Next, in order to verify the performance changes of the medical tubing of this embodiment before and after the polymer coating is applied on its braided layer, this embodiment made corresponding tests on the medical tubing prepared by different preparation methods, To verify the performance improvement of medical tubing. The following embodiments will specifically describe these three preparation methods and their corresponding test results.

Example one

The preparation process of the medical tubing of this embodiment specifically includes:

First perform the dip coating and pulling process: the stainless steel braided wire is fixed with a certain tension using a retracting and unwinding machine, and passes through the dipping tank at a pulling speed of 5 cm/min, where the polymer coating material solution in the dipping tank It is a polyamide solution; after that, the stainless steel braided wire of the above step is placed in a sintering furnace and solidified at a curing temperature of 200-280°C to obtain a stainless steel metal braided wire with a polyamide coating, and the thickness of the polyamide coating is 16 μm ;

Then perform the weaving process: use a braiding machine to braid the stainless steel metal braided wire with polyamide coating on the inner layer of the pipe (the material is Pebax);

Finally, the extrusion process is performed: the inner layer of the braided pipe is fixed with a certain tension by using a take-up and pay-off machine, and a single-screw extruder is used to coat the inner layer of the braided pipe with a layer of outer layer (PA). The extrusion temperature is controlled at 200-270℃. After water bath and cutting, 850mm long medical tubing is obtained.

Example 2

The preparation process of the medical tubing provided in this example is basically the same as that in Example 1, except that the pulling rate is 10 cm/min, and the thickness of the formed polyamide coating is 28 μm.

Example Three

The preparation process of the medical tubing provided in this example is basically the same as that in Example 1, except that the pulling rate is 15 cm/min, and the thickness of the formed polyamide coating is 43 μm.

Example 4

The preparation process of the medical tubing provided in this example is basically the same as that in Example 1, except that the pulling rate is 20 cm/min, and the thickness of the polyamide coating is 57 μm.

The torsion and bending tests of the existing medical tubing and the medical tubing prepared in Example 1 to Example 4 were performed in sequence. Among them, the torsion test process is: after passing 850mm long medical tubing through two parallel plates, connect the proximal end of the medical tubing to the torque input motor; rotate the proximal end of the medical tubing clockwise by 360° (20°/s ), and measure the forward rotation angle of the distal end of the medical tube; after 1 minute, rotate the proximal end of the medical tube counterclockwise by 360° (20°/s), and measure the reverse rotation angle of the distal end of the medical tube. In addition, three-point bending tests were performed on these pipes, and corresponding bending data was obtained. Finally, after the test, the test data recorded in Table 1 was obtained, in which the pulling rate of 0 cm/min and the coating thickness of 0 μm refer to the existing medical tubing.

Table 1: Torque transmission and bending performance of medical tubing at different pulling rates

It can be seen from Table 1 that, compared with the existing medical tubing, the medical tubing of the present invention has a significant improvement in the performance of reverse torsion. In particular, the thicker the coating, the better the torque transmission capacity of the pipe. Among them, when the pulling rate is lower at 5 cm/min, the reverse twisting angle of the pipe is improved by 11.8% compared to the existing pipe. In addition, as the pulling rate increases, the reverse torsion angle increases. For example, when the pulling rate is 10 cm/min, the reverse torsion angle increases by 23.7%; when the pulling rate is 15 cm/min, the reverse torsion angle increases. 32.6%; when the pulling rate is 20cm/min, the reverse torsion angle is increased by 33.7%.

In addition, the bending performance of the medical tube of the present invention is not much different from the existing medical tube at a certain coating thickness. Therefore, the preparation method of the present invention hardly affects the flexibility of the pipe, but when the coating thickness reaches a relatively high value, such as 20 μm, the bending strength of the pipe is significantly improved, and the flexibility of the pipe cannot be guaranteed. Therefore, by providing a polymer coating with a certain thickness, the medical tubing of the present invention can provide sufficient torsion control performance while ensuring the flexibility of the original tubing.

In short, in the medical tubing provided by the present invention, the polymer coating applied on the braided layer can effectively fix the intersection between the metal braided wires, and can also help the braided layer and the outer layer of the tube and the inner layer of the tube The bonding overcomes the problem of poor torque transmission of the pipe in the prior art.

The above description is only a description of preferred embodiments of the present invention, and does not limit the scope of the present invention. Any changes or modifications made by those of ordinary skill in the field of the present invention based on the above disclosure shall fall within the protection scope of the claims.

Claims

A method for preparing medical tubing, characterized in that it includes the following steps:

Providing an original pipe, and using the original pipe as an inner layer of the pipe;

On the outer surface of the inner layer of the pipe, braided with metal braided wire to form an intermediate layer of the pipe, wherein a polymer coating is formed on the surface of the intermediate layer of the pipe, and the polymer coating is used to melt under heat Forming a fixed node at the intersection of the metal braided wires; and

A tube outer layer is formed on the outer surface of the tube intermediate layer.
The preparation method according to claim 1, wherein the polymer coating is applied to the surface of the metal braid before forming the intermediate layer of the pipe.
The preparation method according to claim 2, wherein the step of applying the polymer coating to the surface of the metal braid before forming the intermediate layer of the pipe includes:

Dip coating and pulling the metal braided wire at least once in a solution containing a polymer coating material, and curing the metal braided wire after each dip coating and pulling the metal braided wire, In order to obtain the metal braided wire coated with the polymer coating on the surface.
The preparation method according to claim 3, characterized in that each time the speed of pulling the metal braid is 5-20 cm/min, the temperature for curing the metal braid is 200-280°C.
The preparation method according to any one of claims 1 to 4, wherein the outer layer of the pipe is formed on the outer surface of the middle layer of the pipe by an extrusion process, and the polymer coating is extruded Heated and melted at a temperature to form the fixed node at the intersection of the metal braided wires.
The preparation method according to claim 5, wherein the extrusion temperature of the outer layer of the pipe is 200-270°C.
The preparation method according to claim 1 or 2, wherein the material of the metal braid is selected from one of stainless steel, carbon steel, cast iron, copper, aluminum, nickel, and iron-chromium aluminum alloy.
The preparation method according to claim 1 or 2, wherein the material of the polymer coating is a polymer plastic.
The preparation method according to claim 8, wherein the polymer plastic is selected from one or a combination of polyamide, polyether block amide, and thermoplastic polyurethane.
The preparation method according to claim 1 or 2, wherein the thickness of the polymer coating is 16-57 μm.
The preparation method according to claim 10, wherein the thickness of the polymer coating is 16-43 μm.
A medical tube, characterized in that it is prepared by the preparation method according to any one of claims 1-11.
The medical tubing according to claim 12, wherein the medical tubing has a wall thickness of 0.01 to 0.015 inch.