JP7368190B2 - Method for manufacturing flexible medical tube - Google Patents

Description

FIELD OF THE INVENTION The present invention relates to a flexible tube and a method for manufacturing the same.

As medical tubes, there are known balloon catheters for vasodilation, balloon catheters for gastrostomy, drain tubes, blood flow tubes, and the like. In such tubes, the functionality of the tubes is progressing, and various studies are being conducted to improve the fluidity of the medium in the tube lumen, the operability, and the durability of the tube.

For example, Patent Document 1 discloses a blood vessel tube in which a plurality of spiral protuberances are formed on the inner wall of the tube. This vascular tube can maintain a flow rate by inducing a spiral flow due to the spiral protuberance. Further, Patent Document 2 discloses a medical tube in which a spiral groove is provided on the outer surface of the tube tip. It is stated that the medical tube described in Patent Document 2 has a spiral groove so that the catheter can be easily pushed in and can be inserted smoothly without damaging tissue. It is also described that such a spiral groove can be processed using a laser irradiation device.

Special Publication No. 2002-533157 Japanese Patent Application Publication No. 2000-254235

However, there is no disclosure of a flexible tube with a spiral groove on the inner wall. Generally, a flexible tube having multiple spiral protuberances on the inner wall as described in Patent Document 1 is manufactured by injection molding using a special mold using a thermosetting resin or the like. I can do it. However, when the angle of the helix changes as in Patent Document 2, the injection molding method requires changing the mold depending on the intended use, leading to concerns about increased manufacturing costs and lack of versatility. Furthermore, with the laser processing described in Patent Document 2, it is difficult to form on the inner wall.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a flexible tube having a spiral groove at least on the inner wall, and a manufacturing method for easily obtaining the flexible tube.

The flexible tube of the present invention is made of resin and has at least one spiral groove on its inner wall.

The JIS A hardness of the resin is preferably 15 degrees or more and 60 degrees or less.

The flexible tube of the present invention may further have a spiral groove on the outer wall.

Further, the method for manufacturing a flexible tube of the present invention includes a first step of extruding raw resin into a cylindrical shape while rotating the in-die using an extrusion molding machine having a die consisting of a cylindrical in-die and a cylindrical out-die. and a second step of solidifying the raw material resin extruded into a cylindrical shape, and one spiral groove is formed on at least the inner wall.

In the manufacturing method of the present invention, it is preferable that the in-die protrudes from the out-die by 0 mm or more and 3 mm or less in the extrusion direction.

Moreover, it is preferable that the rotation speed of the in-die is 1 rpm or more and 60 rpm or less.

In the first step, when the temperature of the raw resin is 23° C., the extrusion speed is preferably 0.2 m/min or more and 5 m/min or less.

The Mooney viscosity of the raw material resin is preferably 5 or more and 60 or less.

According to the present invention, a flexible tube having a spiral groove at least on the inner wall can be easily obtained.

FIG. 2 is a side view of a flexible tube of the present invention. 2 is a sectional view taken along line X1-X1 in FIG. 1. FIG. FIG. 1 is a partially enlarged sectional view of a flexible tube of the present invention. 1 is a schematic configuration diagram of an example of an extrusion molding machine used for manufacturing the flexible tube of the present invention. FIG. 2 is a sectional view of a die in an extrusion molding machine used in the present invention. It is a sectional view showing another example of the die in the extrusion molding machine used in the present invention.

Embodiments of the present invention will be described below with reference to the drawings. The following embodiments are presented for the purpose of illustration, and the present invention is not limited to the embodiments shown below.

[Flexible tube]
As shown in FIG. 1, the flexible tube 10 of this embodiment has one spiral groove 12 on the outer wall 10b. Further, as shown in FIG. 2, the flexible tube 10 has one spiral groove 11 formed on the inner wall 10a.
The flexible tube 10 is made of resin. Thermoplastic resins and thermosetting resins can be used as the resin. Examples of the thermoplastic resin include polyethylene, polypropylene, polystyrene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer ABS resin, polyvinyl chloride, polyvinyl chloride, and polystyrene. Examples include vinylidene chloride and methacrylic resin. Further, examples of the thermosetting resin include polyamide, polyamide elastomer, polyester, polyester elastomer, polyurethane, and silicone rubber.
Further, the hardness of the flexible tube 10 is preferably 15 degrees or more and 60 degrees or less in JIS A hardness.

The wall thickness T ₁₀ of the flexible tube 10 can be appropriately selected from 0.2 mm to 1 mm depending on the intended use.
The pitch P ₁₁ of the spiral grooves 11 on the inner wall 10a and the pitch P ₁₂ of the spiral grooves 12 on the outer wall 10b can be manufactured in a range of 0.5 mm or more and 50 mm or less, respectively. The pitches P ₁₁ and P ₁₂ may be equally spaced from one end of the flexible tube 10 to the other, or may vary gradually.

The width W ₁₁ of the spiral groove 11 of the inner wall 10a in the central axis direction and the width W ₁₂ of the spiral groove 12 of the outer wall 10b are each 0.5 mm or more from the viewpoint of maintaining the wall thickness and strength of the flexible tube 10. It is preferable.
The depth _d11 of the spiral groove 11 on the inner wall 10a of the flexible tube 10 and the depth _d12 of the spiral groove 12 on the outer wall 10b (see FIG. 3) are determined from the viewpoint of maintaining the wall thickness and strength of the flexible tube 10. Therefore, it is preferably 50 μm or more and 1000 μm or less, respectively.

Since the flexible tube 10 of the present invention has the spiral groove 11 on the inner wall 10a, it is possible to induce a spiral flow, thereby improving the fluidity of the medium flowing inside.

[Method for manufacturing flexible tube]
The method for manufacturing a flexible tube of the present invention uses an extrusion molding machine having a die consisting of a cylindrical in-die and a cylindrical out-die, and includes a first step of extruding raw resin while rotating the in-die, and This method includes a second step of solidifying the raw material resin.

(Extrusion molding machine)
First, an example of an extrusion molding machine used in the manufacturing method of the present invention will be described with reference to FIGS. 4 and 5.
As shown in FIG. 4, the extrusion molding machine 20 includes an extruder 35 and a die 30. As shown in FIG. 5, the die 30 includes a cylindrical in-die 31 and a cylindrical out-die 32. The in-die 31 is rotatably installed around an axis by a rotation mechanism (not shown). The out-die 32 may include heating means (not shown) for heating the raw resin.

-First step-
In the first step, the raw resin 10A extruded from the extruder 35 is supplied to the passage 34 between the in-die 31 and the out-die 32, and is extruded into a cylindrical shape from the extrusion port 33 while rotating the in-die 31. . The direction of rotation may be either clockwise rotation or counterclockwise rotation toward the extrusion direction X. Hereinafter, the extruded cylindrical tube of the raw material resin 10A will be referred to as the flexible tube 10 before solidification.
As shown in FIG. 5, when the flexible tube 10 before solidification is extruded from the extrusion port 33, the inner wall 10a comes into contact with the corner 31b of the in-die die 31 due to its flexibility, and by rotating the in-die die 31, A spiral groove 11 is formed in the inner wall 10a. At the same time, the outer wall 10b of the flexible tube 10 before solidification comes into contact with the corner 32b of the out die 32, thereby forming the spiral groove 12.

The corner portion 31b of the in-die 31 preferably has an angle of about 90 degrees and a radius of about 0.3 mm.

-Second process-
Next, the raw resin 10A extruded into a cylindrical shape is solidified to obtain the flexible tube 10. The extruded raw material resin 10A is supported by a conveyor belt. The distance from the extrusion port to the conveyor belt depends on the extrusion speed and the rigidity of the in-die material, but is preferably within 1 m. If it exceeds 1 m, the raw resin 10A will sag or stretch, making it difficult to form grooves well.
The solidifying means 40 is a cooling means when the raw resin 10A is a thermoplastic resin, and is a heating means when the raw resin 10A is a thermosetting resin. As the cooling means, a known technique can be used, and a blower or a cooling device can be used. As the heating means, known techniques can be used, including a method of heating with a heater, a method of leaving it at a high temperature, and the like.

Thereafter, the flexible tube 10 solidified by the solidifying means 40 is conveyed by rollers 51 and 52 and wound up by a winding device 60.

The pitches P ₁₁ and P ₁₂ of the spiral grooves 11 and 12 can be adjusted as appropriate by adjusting the extrusion speed of the raw resin 10A, the rotation speed of the in-die 31, and the viscosity of the raw resin 10A.

The rotational speed of the in-die 31 is preferably 1 rpm or more and 60 rpm or less, and more preferably 5 rpm or more and 30 rpm or less. When the rotational speed of the in-die 31 is within the above range, the spiral grooves 11 and 12 can be formed satisfactorily while maintaining the wall thickness of the extruded flexible tube 10 before solidification constant.

The extrusion speed of the raw resin 10A is preferably 0.2 m/min or more and 5 m/min or less, and preferably 0.2 m/min or more and 3 m/min or less when the temperature of the raw resin is 23°C. When the extrusion speed of the raw resin 10A is within the above range, the spiral grooves 11 and 12 can be formed satisfactorily while maintaining a constant wall thickness of the extruded flexible tube 10 before solidification.

The Mooney viscosity of the raw resin 10A is preferably 5 or more and 60 or less. When the viscosity of the raw resin 10A is within the above range, the extrusion amount can be easily controlled and the spiral grooves 11 and 12 can be formed satisfactorily. The Mooney viscosity is the value measured according to DIN 53523 (23° C. large rotor).

In the above embodiment, regarding the arrangement of the in-die 31 and the out-die 32, the end face 31a of the in-die 31 and the end face 32a of the out-die 32 are located at the same position in the vertical direction. 31 may protrude from the end surface 32a of the out die 32 by a distance L in the extrusion direction X. The distance L is preferably 0 mm or more and 3 mm or less. By adjusting the protrusion distance L of the in-die 31, it is possible to adjust the depths _d11 and _d12 of the spiral grooves 11 and 12.

According to the flexible tube manufacturing method of the present invention, the configuration of the helical groove can be controlled by the viscosity and extrusion speed of the raw material resin, and the rotation speed of the in-die without using a special mold. It is possible to easily and accurately manufacture a flexible tube having the following properties.

10 Flexible tube 10A Raw material resin 11, 12 Spiral groove 20 Extrusion molding machine 30 Die 31 In-die 32 Out-die 31a End face of in-die 31b Corner of in-die 32b Corner of out-die 32a End face of out-die 33 Extrusion port 34 Passage 35 Extruder 40 Solidification means 51, 52 Roller 60 Winding device

Claims (5)

Using an extrusion molding machine having a die consisting of a cylindrical in-die and a cylindrical out-die , raw resin is extruded into a cylindrical shape to form a flexible tube before solidification, and the flexible tube before solidification is a first step of forming a spiral groove in the inner wall by bringing the inner wall of the sex tube into contact with the corner of the in-die and rotating the in-die;
A method for manufacturing a flexible medical tube, comprising: a second step of solidifying the unsolidified flexible tube extruded into a cylindrical shape, and forming at least one spiral groove on the inner wall. 2. The method for manufacturing a flexible medical tube according to claim 1 , wherein the in-die protrudes from the out-die by more than 0 mm and 3 mm or less in the extrusion direction. The method for manufacturing a flexible medical tube according to claim 1 or 2 , wherein the rotation speed of the in-die is 1 rpm or more and 60 rpm or less. The flexible medical tube according to any one of claims 1 to 3, wherein in the first step, when the temperature of the raw material resin is 23°C, the extrusion speed is 0.2 m/min or more and 3 m/min or less. manufacturing method. The method for manufacturing a flexible medical tube according to any one of claims 1 to 4 , wherein the raw material resin has a Mooney viscosity of 5 or more and 60 or less.

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