JP2001309882A - Flexible tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible tube which is achieved to be thinner than an existing flexible tube and maintains flexibility and the nature of not kinking. SOLUTION: A flexible tube 10, which has a tube wall with a reinforcing layer 2 placed between an inner layer 1 and an outer layer 3 made of resin. The reinforcing layer 2 is formed by weaving rectangular wires 4a, 4b. Thickness A of the rectangular wires 4a, 4b must be more than 15 μm but less than 25 μm. The part which falls on a bended part L for the rectangular wires 4a, 4b should be wrapped up in a manner that a weaving pitch C becomes less than 6 mm. Also, the values for the thickness A, the width B, and the weaving pitch C should be set up to satisfy these two inequalities, A×B>700 and A×B×C<7500.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible tube, and more particularly to a flexible tube that is to be bent.

[0002]

2. Description of the Related Art In recent years, endoscopes have been actively used for performing body examinations and surgeries by inserting them into blood vessels and internal organs.
An endoscope is usually configured by housing an image guide, a light guide, a working channel tube, and a swing mechanism in a tube serving as an exterior. Of these, the working channel tube is used for injecting a drug solution into an affected part or inserting tools such as forceps.

[0003] In this working channel tube,
Flexibility, kink resistance and pinhole resistance are required. The flexibility is required because the endoscope is provided with a swing mechanism, and if the flexibility is poor, a large force is required at the time of swinging, thereby increasing the burden on the swing mechanism. . Kink resistance is required because the endoscope is bent to a maximum of about 160 degrees by the swing mechanism, and the working channel tube is twisted (kinks) at this time.
This causes a problem that insertion of forceps or the like cannot be performed. Pinhole resistance is required because it is necessary to prevent leakage of the chemical solution.

[0004] Further, since the endoscope is inserted into a blood vessel, an internal organ, or the like, it is desired that the outer diameter of the endoscope be as small as possible. Therefore, it is desired that the outer diameter of the working channel tube be as small as possible. Further, in the working channel tube, it is desirable that the inner diameter of the working channel tube be as large as possible in order to allow insertion of the forceps as large as possible and increase the amount of the medicinal solution that can be injected. That is, the working channel tube satisfies flexibility, kink resistance and pinhole resistance, and
It is required that the tube wall be thin.

In order to satisfy such a demand, conventionally,
As a working channel tube for an endoscope, a flexible tube having a multi-layered tube wall is used. As a typical example of such a flexible tube, a flexible tube having a multilayer structure in which a reinforcing layer made of a rectangular wire is provided between an inner layer made of a fluorine resin and an outer layer made of a polyurethane resin is known. In this flexible tube, the flexibility and the kink resistance are secured by the reinforcing layer, and the pinhole resistance is secured by the inner layer and the outer layer.

Usually, the reinforcing layer is formed of a braid formed by winding a rectangular wire on the inner layer. Since the flexibility and kink resistance of the flexible tube can be improved as the braid pitch of the braid is reduced, it is a preferable embodiment that the reinforcing layer is formed with the braid pitch as small as possible. However, if an attempt is made to reduce the braid pitch over the entire reinforcing layer, the production speed is reduced, and the productivity is reduced.

[0007] Therefore, in general, the braid pitch of the flat wire only at a portion where flexibility and kink resistance are particularly required, that is, at a portion where bending is planned (hereinafter referred to as a "bending portion"). Is set to be small (less than 6 mm). In other parts, the braid pitch is set large (6 mm or more) to increase the production speed.

[0008]

In the above-mentioned flexible tube having a multilayer structure, the pinhole resistance is secured between the inner layer and the outer layer as described above. In this case, the thickness of the inner layer made of fluororesin is 30 μm. As described above, the thickness of the outer layer made of the polyurethane resin needs to be 50 μm or more. For this reason, if the thickness of the rectangular wire forming the reinforcing layer is large, the wall of the flexible tube exceeds 100 μm, which is unsuitable for use as a working channel of an endoscope. On the other hand, if a thin rectangular wire is used, the thickness of the tube wall can be made less than 100 μm, but the required flexibility and kink resistance at the portion to be bent may not be secured.

An object of the present invention is to provide a flexible tube which can be made thinner than before and can secure sufficient flexibility and kink resistance.

[0010]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, the values of the thickness [μm], width [μm] and braid pitch [mm] of the flat wire have been set. It has been found that if the thickness is set so as to satisfy a certain relationship, flexibility and kink resistance are not impaired even if the thickness of the rectangular wire is reduced. The flexible tube of the present invention has been made based on this finding, and has the following features. In addition, the flat wire referred to in the present invention refers to a wire whose cross section perpendicular to the central axis is rectangular or substantially rectangular, or a wire whose cross section has a shape in which both short sides of the rectangle are bulged in an arc shape. Flat wire width B
Means the length in the longitudinal direction in the cross section, and the thickness A of the rectangular wire means the length in the direction perpendicular to the longitudinal direction in the cross section.

(1) It has a pipe wall provided with a reinforcing layer between an inner layer and an outer layer formed of a resin material, and the reinforcing layer is formed by a braid formed by a flat wire. The rectangular wire constituting the reinforcing layer has a thickness A exceeding 15 μm and 25 mm.
μm, and at least a part of the flat wire is wound so that the braid pitch C is less than 6 mm,
A flexible tube in which the thickness A, width B, and braid pitch C of the rectangular wire satisfy the following formulas (1) and (2) at the portion. A × B> 700 (1) A × B × C <7500 (2)

(2) The flexible tube has a portion that is to be bent, and at least a portion of the rectangular wire forming the reinforcing layer is located at the portion that is to be bent. The flexible tube according to (1).

(3) The flexible tube according to the above (1), wherein the inner layer is formed of a fluorine resin and the outer layer is formed of a polyurethane resin.

(4) The thickness of the tube wall is 50 μm to 100 μm
m, the flexible tube according to the above (1).

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a flexible tube according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a view showing an example of the flexible tube of the present invention, and a part of an outer layer is shown in a cross section.
FIG. 2 is a view showing an example of a rectangular wire constituting the reinforcing layer of the present invention, and shows only a part. 3A to 3D are views showing an example of the method for manufacturing the flexible tube of the present invention shown in FIG. 1, and FIGS. 3A to 3D show the manufacturing method for each step.

As shown in the example of FIG. 1, the flexible tube 1 of the present invention
Numeral 0 indicates that bending is to be performed, and has a bent portion L. M indicates other sites. The flexible tube 10 of the present invention is particularly useful for a working channel of an endoscope provided with a swing mechanism. The flexible tube 10 of the present invention
Reinforcing layer 2 between inner layer 1 and outer layer 3 formed of resin material
Is provided.

The reinforcing layer 2 is provided on the inner layer 1,
It is composed of a braid of the flat wire 4a and the flat wire 4b. The braided reinforcing layer 2 ensures the flexibility and kink resistance of the flexible tube 10. As the rectangular wires 4a and 4b constituting the reinforcing layer 2, the thickness A exceeds 15 μm and is 2 mm.
Less than 5 μm, preferably 16 μm to 23 μm,
The width B is 40 μm to 90 μm, preferably 50 μm to 60 μm.
μm is used.

A part of the flat wires 4a and 4b, in the example of FIG.
mm, preferably 1 mm to 5 mm. In this portion, the thickness A, the width B, and the braid pitch C satisfy the following expressions (1) and (2). In the formulas (1) and (2), the unit of the thickness A and the width B is μm, and the unit of the braid pitch C is mm. A × B> 700 Equation (1) A × B × C <7500 Equation (2)

If the values of the thickness A, the width B, and the braid pitch C of the flat wires 4a and 4b are set so as to satisfy all of the above conditions in the portion located at the portion L to be bent, The bent portion L of the flexible tube 10 has the flexibility and the kink resistance secured, despite the fact that the reinforcing layer 2 is formed by a thin rectangular wire.

In order to improve the production speed, the braid pitch C 'in the portion M other than the planned bending portion L is larger than the braid pitch C in the planned bending portion L. Further, as shown in the example of FIG. 2, the rectangular wires 4a and 4b have a uniform thickness A and width B from one end to the other end.

Next, a method for manufacturing the flexible tube 10 of the present invention shown in FIG. 1 will be described with reference to FIG. First, as shown in the example of FIG.
Is provided. The inner layer 1 is partially shown in section,
The cross section is hatched.

In the example of FIG. 3A, a stainless steel wire is used as the core wire 5. The core wire 5 is not limited to this, and a wire made of a metal material other than stainless steel or a resin material, for example, a mild steel wire, a nickel-plated soft copper wire, or the like can be used. However, in the present invention, as described above, the core wire 5 is preferably made of a stainless steel wire because copper powder and plating scum do not adhere to the inner surface of the flexible tube. Further, in the example of FIG. 3A, the cross section of the core wire 1 is circular, but this is not particularly limited.
The outer diameter and length of the core wire 5 are not particularly limited, and may be appropriately set according to the inner diameter and length of the flexible tube.

In the example of FIG. 3A, the inner layer 1 is formed by extrusion-coating the core wire 5 with a fluororesin. In the present invention, the resin material forming the inner layer 1 is not limited to a fluororesin, but other thermoplastic polyurethane, nylon 66, nylon 6,
Polyamide resins such as nylon 12 and nylon 612 can also be used. However, the pull-out property of the core wire,
It is preferable to use a fluororesin having a small friction coefficient in consideration of the insertion of the forceps and the laser irradiation fiber.

Further, in the present invention, the method for forming the inner layer 1 is not limited to extrusion coating, and other methods for forming the inner layer 1 include a dip coating method.
However, extrusion coating is preferred because continuous molding is possible and the cost is low. In the present invention, the thickness of the inner layer 1 is preferably set to 30 μm to 60 μm, particularly preferably 40 μm to 50 μm, because it is necessary to make the wall of the tube as thin as possible while maintaining the pinhole resistance. preferable.

Next, as shown in the example of FIG. 3B, a reinforcing layer 2 is formed on the inner layer 1. The reinforcing layer 2 is a flat wire 4
a and the flat wire 4b are woven into a net shape.
Here, the term “net-like” refers to a state in which a plurality of rectangular wires are spirally wound in different winding directions so as to intersect the outer periphery of the first resin layer 2 regularly. .

In the example shown in FIG. 3B, the reinforcing layer 2 is formed by:
It is performed by a braiding machine. A known device can be used as the braiding machine. As a specific example of the braiding machine,
A first rotating body for rotating the bobbin around which the rectangular wire 4a is wound around the core wire 5, a second rotating body for rotating the bobbin around which the rectangular wire 4b is wound around the core wire 5, and a rectangular wire; And an arm that moves up and down to weave the first rotating body and the second rotating body so that they rotate in opposite directions about the core wire 1.

In the example of FIG. 3 (b), the winding of the flat wire 4a and the flat wire 4b is performed so that the braid pitch C at the portion L to be bent is smaller than the braid pitch C 'of the other portions M. Is being done. Braid pitch C is 6m
m or more, the flexibility and kink resistance required for the to-be-bent portion L cannot be ensured.
Set to less than. The braid pitch C 'is preferably set to 6 mm to 10 mm, and more preferably 7 mm to 9 mm from the viewpoint of improving the production speed. However, the reason why the braid pitch C ′ is made larger than the braid pitch C is from the viewpoint of the production speed as described above, and in the present invention, the braid pitch C ′ is set to be equal to or less than the braid pitch C. Is also good.

In the present invention, the flat wires 4a and 4b are
It can be produced by rolling a wire having a circular cross section or the like with a roll to flatten the cross section, or by extruding the wire into a rectangular or substantially rectangular cross section. In the examples of FIGS. 1 to 3, the flat wires 4a and 4b have a uniform thickness A and a uniform width B from one end to the other end as described above. A rectangular wire in which one or both of the width A and the width B continuously or stepwise can be used.

In the present invention, examples of the material forming the rectangular wires 4a and 4b include metal materials such as stainless steel, copper and Ni-Ti alloy, and resin materials such as nylon and polyester. Among them, stainless steel is preferred from the viewpoint of corrosion resistance and strength.

Next, as shown in FIG. 3C, an outer layer 3 made of a resin material is provided on the reinforcing layer 2. Outer layer 3
Is partially shown in cross section, and the cross section is hatched. In the example of FIG. 3C, the outer layer 3 is formed by dip coating with a polyurethane resin. Specifically, the outer layer 3 is formed by alternately performing a step of immersing the one obtained in FIG. 3B in a dimethylformamide solution in which a polyurethane resin is dissolved and a step of heating and drying the removed one several times. It is formed by performing.

However, in the present invention, the material for forming the outer layer 3 is not limited to a polyurethane resin, and other nylon resins, polyethylene resins, polypropylene resins, and the like can be used. However, it is preferable to use a polyurethane resin from the viewpoint of antithrombotic properties and adhesiveness.
Further, the method of forming the outer layer 3 is not limited to the above-described dip coating, and a method such as extrusion coating can be used. However, it is preferable to use the dip coating in view of the thin-film formability and the fact that the forming material of the outer layer easily reaches the lower part of the braid.

In the present invention, the thickness of the outer layer 3 is preferably set to 10 μm to 70 μm because it is necessary to make the wall of the tube as thin as possible while maintaining the pinhole resistance similarly to the inner layer 1. It is particularly preferred that the thickness be 30 μm to 50 μm.

Finally, as shown in FIG. 3D, the core wire 1 is pulled out, and the flexible tube 10 of the present invention is completed. Cross sections of the inner layer 1 and the outer layer 3 are hatched.
Specifically, the core wire 5 can be pulled out by removing the inner layer and the outer layer of about 1 cm at both ends and extending the core wire 5 by about 10 cm to 20 cm.

When the flexible tube 10 is manufactured as shown in FIGS. 3A to 3D, the thickness of the tube wall is 50 μm or more.
The thickness can be reduced to less than 0 μm, preferably 70 μm to 90 μm. Furthermore, since sufficient flexibility and kink resistance can be ensured at the bent portion L, the flexible tube 10 of the present invention can be suitably used as a working channel tube of an endoscope.

[0035]

EXAMPLE A flexible tube of the present invention shown in FIG. 1 was actually manufactured according to the process shown in FIG. First, the outer diameter of the core wire is 1.2m
An inner layer (thickness: 40 μm) made of a fluororesin was formed on a stainless steel (SUS304) wire having a length of 1200 mm and a length of 1200 mm by an extrusion coating method. The surface of the inner layer was subjected to a surface treatment using a surface treatment agent (trade name: "Tetra-etch", manufactured by Junko Co., Ltd.).

Next, a stainless steel having a circular cross section (SUS3
A flat wire (thickness A: 22 μm, width: B: 57 μm) produced by rolling a wire rod manufactured by a roll method with a roll has a braid pitch C of 1 mm.
The reinforcement layer was manufactured by braiding so that A ×
B is 1254 and A × B × C is 1254.

Further, a polyurethane resin (T
Hermedics Co., Ltd., trade name "Tecoflex")
Was dip-coated to form an outer layer. Specifically, the outer layer is made of dimethylformamide in which polyurethane is dissolved (temperature: 50 ° C., compounding ratio: dimethylformamide 93% by weight)
And a step of immersing the core wire, the inner layer and the reinforcing layer in 5% for 5 minutes, and a step of taking out and heating and drying (60 ° C., 10 minutes) each alternately twice. Further, it was formed by drying at 60 ° C. for 16 hours. Finally, the core wire was pulled out. The outer diameter of the obtained flexible tube of the present invention is 1.36 mm, and the wall thickness of the tube wall is 80 μm.
m, and the total length was 1000 mm.

Next, the flexible tube obtained above was evaluated for flexibility and kink resistance. The flexibility was determined by performing a three-point bending according to JIS K7203, measuring the load when the deflection at the center of the flexible tube was 2 mm, and evaluating the value of the load. The kink resistance is 160
The specimen was bent to ℃, and the presence or absence of buckling was visually confirmed and evaluated. Table 1 shows the results. In Table 1, the flexibility was evaluated as ○ when the load was 0.1 N or less, and as × when the load exceeded 0.1 N. The kink resistance was evaluated as 場合 when buckling was not confirmed, and as X when buckling was confirmed. The case where the wall thickness was 100 μm or less was evaluated as ○, and the case where the thickness exceeded 100 μm was evaluated as ×.

Example 2 A flexible tube was prepared in the same manner as in Example 1 except that the braid pitch of the rectangular wire was changed to 2 mm, and the flexibility and kink resistance were evaluated. In this case, A × B is 1254, A × B × C
Was 2508. The outer diameter of the obtained flexible tube is 1.36 mm, the wall thickness of the tube is 80 μm, and the total length is 1000.
mm. Table 1 shows the results.

Example 3 A flexible tube was produced in the same manner as in Example 1 except that the braid pitch of the rectangular wire was 4 mm, and the flexibility and kink resistance were evaluated. In this case, A × B is 1254, A × B × C
Was 5016. The outer diameter of the obtained flexible tube is 1.36 mm, the wall thickness of the tube is 80 μm, and the total length is 1000.
mm. Table 1 shows the results.

Example 4 A rectangular wire having a thickness of 20 μm and a width of 63 μm was used.
A flexible tube was produced in the same manner as in Example 1 except that the braid pitch was set to 2 mm, and the flexibility and the kink resistance were evaluated. In this case, A × B is 1260 and A × B × C is 252.
It was 0. The outer diameter of the obtained flexible tube is 1.355.
mm, the wall thickness of the tube wall was 75 μm, and the total length was 1000 mm. Table 1 shows the results.

Example 5 A rectangular wire having a thickness of 18 μm and a width of 70 μm was used.
A flexible tube was produced in the same manner as in Example 1 except that the braid pitch was set to 2 mm, and the flexibility and the kink resistance were evaluated. In this case, A × B is 1260 and A × B × C is 252.
It was 0. The outer diameter of the obtained flexible tube is 1.35 m.
m, the wall thickness of the tube wall was 70 μm, and the total length was 1000 mm. Table 1 shows the results.

Comparative Example 1 A flexible tube was prepared in the same manner as in Example 1 except that the braid pitch of the rectangular wire was 6 mm, and the flexibility and kink resistance were evaluated. In this case, A × B is 1254, A × B × C
Was 7524. The outer diameter of the obtained flexible tube is 1.36 mm, the wall thickness of the tube is 80 μm, and the total length is 1000.
mm. Table 1 shows the results.

Comparative Example 2 A rectangular wire having a thickness of 15 μm and a width of 84 μm was used.
A flexible tube was produced in the same manner as in Example 1 except that the braid pitch was set to 2 mm, and the flexibility and the kink resistance were evaluated. In this case, A × B is 1260 and A × B × C is 252.
It was 0. The outer diameter of the obtained flexible tube is 1.35 m.
m, the wall thickness of the tube wall was 70 μm, and the total length was 1000 mm. Table 1 shows the results.

Comparative Example 3 A rectangular wire having a thickness of 25 μm and a width of 50 μm was used.
A flexible tube was produced in the same manner as in Example 1 except that the braid pitch was set to 2 mm, and the flexibility and the kink resistance were evaluated. In this case, A × B is 1250 and A × B × C is 250
It was 0. The outer diameter of the obtained flexible tube is 1.41 m.
m, the wall thickness of the tube wall was 105 μm, and the total length was 1000 mm. Table 1 shows the results.

Comparative Example 4 A rectangular wire having a thickness of 20 μm and a width of 35 μm was used.
A flexible tube was produced in the same manner as in Example 1 except that the braid pitch was set to 2 mm, and the flexibility and the kink resistance were evaluated. In this case, A × B is 700, A × B × C is 1400
Met. The outer diameter of the obtained flexible tube is 1.36 m.
m, the wall thickness of the tube wall was 80 μm, and the total length was 1000 mm. Table 1 shows the results.

[0047]

[Table 1]

[0048]

As can be seen from the above description, according to the flexible tube of the present invention, the wall thickness of the tube can be reduced while ensuring flexibility and kink resistance. Therefore, by using the flexible tube of the present invention as a working channel tube of an endoscope, it is possible to reduce the diameter of the endoscope, to insert a forceps larger than before, and to further inject a drug. Can also be increased.

[Brief description of the drawings]

FIG. 1 is a view showing an example of a flexible tube of the present invention.

FIG. 2 is a view showing an example of a flat wire constituting a reinforcing layer in the flexible tube of the present invention.

FIG. 3 is a diagram showing an example of a method for manufacturing the flexible tube of the present invention shown in FIG. 3A to 3D show the manufacturing method for each step.

[Explanation of symbols]

 Reference Signs List 1 inner layer 2 reinforcing layer 3 outer layer 4a rectangular wire 4b rectangular wire 5 core wire 10 flexible tube L bent portion

Claims (4)

[Claims] 1. A pipe wall having a reinforcing layer provided between an inner layer and an outer layer formed of a resin material, wherein the reinforcing layer is formed by a braid formed by a rectangular wire. The rectangular wire forming the layer has a thickness A of more than 15 μm and less than 25 μm, and at least a part of the rectangular wire is wound so that the braid pitch C is less than 6 mm, and the thickness A of the rectangular wire in the portion is A flexible tube that satisfies the following formulas (1) and (2) with the width B and the braid pitch C. A × B> 700 (1) A × B × C <7500 (2) 2. The flexible tube has a portion that is to be bent, and at least a part of a rectangular wire forming the reinforcing layer is located at the portion that is to be bent. 2. The flexible tube according to 1. 3. The flexible tube according to claim 1, wherein the inner layer is formed of a fluorine resin and the outer layer is formed of a polyurethane resin. 4. The flexible tube according to claim 1, wherein the thickness of the tube wall is 50 μm to 100 μm.