JP2001299922A - Flexible tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible tube excellent in push-in property, torque transmissibility and follow-up property and particularly excellent in kinking resistance in which the braid of a linear body is never disordered or sagged, or a buckling is hardly caused even in the vicinity of the tip part. SOLUTION: This flexible tube 1 comprises a reinforcement layer interposition layer 2 for mutually fixing a substantially cylindrical flexible inner tube 3 and outer tube 4 through a reinforcement layer 5 so that the inner tube 3 is located on the inside of the outer tube 4. The reinforcement layer 5 has a reinforcing material 12 consisting of a straight angle-shaped body 11 with a tensile strength of 500-2,000 MPa or a plurality of thereof in a net shape so that the angle formed by each straight angle-like body 11 to the axial direction A of the inner tube 3 is changed stepwise or continuously substantially along the axial direction A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible tube suitable for a catheter such as an imaging catheter, a guiding catheter, and an expansion catheter.

[0002]

2. Description of the Related Art A catheter such as a contrast catheter, a guiding catheter, and a dilatation catheter is required to have excellent operability such that it can be quickly and reliably inserted into a vascular system having a fine and complicated pattern. . For this reason, a flexible tube for a catheter is required to simultaneously satisfy the following characteristics with one tube. (1) Pushing force by which the operator's pushing force to penetrate the blood vessel can be reliably transmitted from the proximal end to the distal end of the catheter on the operator's hand side. (2) Applied at the proximal end Torque transmission so that rotational force can be reliably transmitted to the distal end. (3) Followability so that it can proceed smoothly in a curved blood vessel along a preceding guide wire without damaging the blood vessel inner wall. (4) Purpose Kink resistance so that the tube tip does not buckle at the curved or bent part of the blood vessel even after the guide wire has been pulled out and the guide wire pulled out

[0003] Japanese Patent Application Laid-Open No. 6-134034 discloses a catheter tube satisfying the above-mentioned characteristics. The catheter tube has a main portion in which a flexible inner tube and an outer tube are joined via a reinforcing material layer, and a tip portion in which the inner tube and the outer tube are joined without a reinforcing material layer interposed therebetween. A catheter body. The reinforcing material layer is for imparting bending rigidity to the main part, and is formed by braiding a linear body in a lattice shape so as to be in contact with the outer surface of the inner tube and the inner surface of the outer tube.

Further, in the above catheter tube, the angle of inclination of the linear body with respect to the axis of the catheter body is gradually increased in the axial direction so that the bending rigidity changes stepwise or continuously in the axial direction of the catheter body. Alternatively, the braid state is set so as to change continuously. When the catheter tube is used, the distal end portion is a portion that is required to be bent more frequently than the base end portion on the opposite side, and is required to have appropriate rigidity and appropriate flexibility. Therefore, the braided state is, specifically, such that the inclination angle of the linear body becomes smaller from the distal end side to the proximal end side of the catheter tube, in other words, the bending rigidity of the catheter body becomes closer to the distal end side. It is set to decrease as it goes.

In such a conventional catheter tube, a single wire having a circular cross section or a collective wire formed by twisting a plurality of the single wires has been often used as the linear body. As a material of the single wire, a hard wire such as SUS304 or SUS316 has been generally used in order to impart sufficient bending rigidity to the main part. However, such a linear body has a small area in contact with the outer surface of the inner tube also having a circular cross section, and it has been difficult to stably hold the inner surface on the outer surface during braiding. In addition, since hard wires are used, it is difficult to braid itself, and there is a problem that it is not possible to braid a regular lattice spacing. Therefore, even if such a linear body is braided, the linear body is disturbed or sagged, and cannot be braided according to a preset braided state, and a portion having an undesirably large lattice spacing is formed. There was a problem that was done.

If a portion having a large lattice spacing is formed undesirably, the bending rigidity of the portion becomes insufficient. Therefore, if the catheter tube is bent so as to bend or bend at the portion, buckling may occur at the portion. In particular, since the bending rigidity is set in advance near the distal end portion in advance as compared with the base end side as described above, there is a problem that the tube is likely to buckle near the distal end portion.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide not only the above-described pushability, torque transmission and followability but also no disturbance or sagging of the braid of the linear body and buckling near the tip. An object of the present invention is to provide a high-quality flexible tube suitable as a catheter tube which is particularly excellent in kink resistance, in which the occurrence of kinking is difficult.

[0008]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have obtained a tensile strength of 500.
Excellent indentation, torque transmission and followability are achieved by fixing a reinforcing material layer formed by braiding a rectangular linear body of MPa to 2000 MPa in a net-like state while being interposed between an inner layer and an outer layer. In addition, it has been found that a flexible tube suitable as a catheter tube which is particularly excellent in kink resistance, in which the braid of the linear body is not disturbed and buckling does not easily occur even near the distal end portion, is provided. The invention has been completed.

That is, the present invention is as follows. (1) A substantially cylindrical inner tube and outer tube each having flexibility,
What is claimed is: 1. A flexible tube having a reinforcing material layer interposed portion that is fixed via a reinforcing material layer so that an inner tube is inside an outer tube, wherein the reinforcing material layer has a tensile strength of 500 MPa to 2000 MPa.
One or a plurality of rectangular linear bodies of MPa are braided in a net shape, and the angle formed by each rectangular linear body with respect to the axial direction of the inner pipe is stepwise or continuous substantially along the axial direction. A flexible tube having a reinforcing material that changes into a flexible tube. (2) The angle formed by each rectangular linear body with respect to the axial direction of the inner tube changes so as to increase stepwise or continuously from one end to the other end. The flexible tube according to the above (1). (3) The above (1), which is for a catheter.
Or the flexible tube according to (2).

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
FIG. 1 is a side view schematically showing a reinforcing member layer interposition portion 2 of a flexible tube 1 according to a preferred embodiment of the present invention in a partially cutaway state. FIG. 2 is a side view of the flexible tube 1 of FIG. Cutting plane line I in an imaginary plane perpendicular to the axial direction A of the inner tube 3
FIG. 3 is a simplified cross-sectional view from the viewpoint of -I, and FIG. 3 is a simplified view of a preferred example of a catheter 6 using the flexible tube 1 of FIG. As shown in FIGS. 1 and 2, the flexible tube 1 of the present invention has a reinforcing material layer having a flexible inner tube 3 and an outer tube 4 and a reinforcing material layer 5 interposed therebetween. An intervening part 2 is provided. The inner tube 3 and the outer tube 4 are interposed between the outer surface 3a of the inner tube 3 and the inner surface 4a of the outer tube 4 via the reinforcing material layer 5 so that the inner tube 3 is located inside the outer tube 4. It is fixed. The flexible tube of the present invention is particularly suitably used for a catheter. In addition, the inner pipe 3 and the outer pipe 4
The axial directions of the flexible tube 1 and the flexible tube 1 are the same direction A.

As shown in FIG. 3, the flexible tube 1 has a tip 7 connected to one end 2a of the interposed reinforcing material layer 2 in addition to the interposed reinforcing material layer 2 described above. The tip portion 7 is different from the reinforcing material layer interposition portion 2 in that the reinforcing material layer 5 is not interposed between the inner pipe 3 and the outer pipe 4. When used for the catheter 6, a hub 8 is attached to the other end 2b of the reinforcing material layer interposed portion 2 opposite to the one end 2a. As shown in FIGS. 1 and 2, the flexible tube 1 has a lumen 10 formed therein. The lumen 10 extends from the proximal end 9 of the flexible tube 1 to the distal end 7. The lumen 10 corresponds to the internal space of the inner tube 3 and serves as a flow path for a drug solution or the like when the flexible tube 1 of the present invention is used for a catheter. At the time of insertion into a blood vessel, a guide wire is inserted into the lumen 10. The hub 8 functions as an injection port for a drug solution or the like into the lumen 10 and an insertion port for the guide wire, and also functions as a grip when the flexible tube 1 is operated.

The inner tube 3 is a substantially cylindrical tube member, and is preferably realized in a perfect circular cylindrical shape as shown in FIG.
The material for forming the inner tube 3 is not particularly limited as long as it has a degree of flexibility and rigidity required when molded as a flexible tube. Preferred materials include, for example, Polytetrafluoroethylene (P
TFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (PF
A) such as a fluororesin, nylon 66, nylon 6,
Examples thereof include a polyamide resin such as nylon 612 and a thermoplastic urethane resin, and among them, a fluorine resin is preferable. Such an inner tube 3 preferably has an inner diameter R1 of 0.3 mm to 2.5 mm, more preferably 0.5 mm to 2.5 mm.
2.0 mm, the outer diameter R2 of which is preferably 0.4 m
m to 2.6 mm, more preferably 0.6 mm to 2.1 m
m. The inner pipe 3 preferably has a Shore D hardness of 40 to 80, more preferably 50 to 70.
Is realized as follows.

The outer tube 4 is also a cylindrical tube member similar to the inner tube 3, and is preferably realized in a perfect circular cylindrical shape. The material for forming the outer tube 4 is not particularly limited as long as it has a degree of flexibility and rigidity required when molded as a flexible tube. Examples include polyurethane resin, nylon resin, polyethylene resin, and polypropylene resin. When the flexible tube of the present invention is used for a catheter, a polyurethane resin having particularly excellent antithrombotic properties is preferable among the above. Such an outer tube 4 has an outer diameter R3
Is preferably 0.7 mm to 4.0 mm, more preferably 0.9 mm to 2.5 mm. The inner diameter R4 of the outer tube 4 is preferably substantially equal to the outer diameter R2 of the inner tube 3 described above. The outer pipe 4 preferably has a Shore D hardness of 40.
To 80, more preferably 50 to 70.

In the flexible tube 1 of the present invention, the angle formed with respect to the axial direction A of the tube 1 changes stepwise or continuously substantially along the axial direction A as described later. By braiding the rectangular linear body 11, the bending rigidity in the axial direction A is adjusted so as to change stepwise or continuously. Therefore, the change in the bending stiffness does not have to be adjusted by the difference in stiffness of the constituent materials used for the inner pipe 3 and the outer pipe 4, and the inner pipe 3 and the outer pipe 4 may be made of the same material. When the inner tube 3 and the outer tube 4 are made of the same material, the manufacturing of the flexible tube 1 can be made easier and the manufacturing cost can be made lower.

Further, in the constituent material of the inner tube 3 and / or the outer tube 4, preferably in the constituent material of the outer tube 4, X
An X-ray contrast agent is kneaded so that the position of the flexible tube 1 can be confirmed under fluoroscopy. Examples of the X-ray contrast agent include metal powder of platinum, gold, silver, tungsten or an alloy thereof, barium sulfate, bismuth oxide, or a coupling compound thereof.

The inner pipe 3 and the outer pipe 4 have respective diameters R1 to R4.
May be constant along the axial direction A of the tube 1, respectively, or may vary within the range of each suitable diameter along the axial direction A. For example, as described later, when the flexible tube 1 of the present invention has a configuration in which the angle formed by the rectangular linear body 11 with respect to the axial direction A changes stepwise, the angle of the rectangular linear body 11 changes. Before and after, and before and after the boundary where the tip 7 and the reinforcing material layer interposed part 2 are continuous, the outer diameter R2 of the inner pipe 3 or the outer diameter R3 of the outer pipe 4 faces the tip 7 along the axial direction A. Or gradually decrease the inner tube 3
Similarly, the inner diameter R <b> 1 may gradually increase toward the distal end portion 7.

The reinforcing material layer 5 interposed between the inner pipe 3 and the outer pipe 4 has a reinforcing material 12 in which a plurality of rectangular wires 11 are braided in a net shape. In this specification, the term “rectangular linear body” refers to a linear body having a substantially rectangular cross section perpendicular to its extending direction. In this specification, a direction along a long side of the substantially rectangular section is defined as a width direction of the rectangular linear body 11, and a direction along a short side substantially perpendicular to the long side is defined as a rectangular linear body. 11 thickness direction. The above-described substantially rectangular shape includes a shape in which at least one of the long side and the short side is a curve, and also includes a substantially square shape. When the cross-sectional shape is substantially square, a direction along any one of the four sides is defined as a width direction, and a direction substantially perpendicular to the direction is defined as a thickness direction.

The flat linear body 11 is made of JIS G430
The tensile strength measured by the measuring method specified in 9 is 50
0 MPa to 2000 MPa, preferably 650 MPa to
1750 MPa, more preferably 1000 MPa to 15
One having a pressure of 00 MPa is used. SUS304, SUS316, SU
S201, SUS303, SUS305, SUS30
9, stainless steel wire such as SUS310, and SUS304 is particularly preferable. The size of the rectangular wire 11 is not particularly limited as long as it is suitable for the braid, but its width is preferably 40 μm to 200 μm, more preferably 50 μm to 100 μm, and its thickness is preferably 5 μm to 50 μm , More preferably 20 µm to 4
0 μm.

The rectangular linear body 11 has a thickness direction
Are braided in a net shape so as to substantially coincide with the radial direction. The “net shape” referred to in the present specification refers to a flat angle braided by, for example, spirally winding a plurality of flat linear bodies 11 around the outer surface 3a of the inner tube 3 without changing the winding direction and without loosening. It refers to a braid state in which the linear bodies 11 regularly intersect with each other. In the example shown in FIG. 1, the rectangular linear bodies 11 regularly intersect with each other, so that each rectangular linear body 1
The portions 13 which are so-called meshes surrounded by 1 have a rhombic shape, and are braided so that the area of the portion 13 is substantially uniform in, for example, each of the regions 14, 15, 16 described later. The number of used rectangular wire bodies 11 is not particularly limited as long as it is braided into the mesh shape, and may be one or a plurality of wires. The braid is formed using the body 11.

In the present invention, the rectangular wire is braided so that the angle formed by each rectangular wire with respect to the axial direction of the flexible tube changes substantially along the axial direction. The change of the angle may be stepwise or continuous. FIG. 1 shows a case where the angle changes stepwise. When the angle formed by each of the rectangular linear members 11 with respect to the axial direction A of the flexible tube 1 changes stepwise, the reinforcing material layer intervening portion 2 is divided into a plurality of regions along the axial direction A. In FIG. 1, for example, the reinforcing material layer intervening portion 2 is sequentially formed from the distal end region 7, the intermediate region 15, and the proximal end region 16 of the flexible tube 1 from the distal end 7 side to the proximal end 9 side. An aspect divided into three regions is shown.

In such a flexible tube 1, as shown in FIG. 1, the rectangular linear body 11 in the distal region 14 forms an angle θ 1 with respect to the axial direction A, and the rectangular linear body 11 in the intermediate region 15. The body 11 forms an angle θ2 with respect to the axial direction A, and the flat linear body 11 in the proximal region 16 is aligned with the axial direction A.
When the angle θ3 is satisfied, the relationship of θ1>θ2> θ3 holds. The angle θ1 is preferably 50 ° to 90 °.
°, more preferably selected from the range of 60 ° ~ 80 °,
The angle θ2 is preferably selected from the range of 35 ° to 65 °, more preferably 45 ° to 55 °.
Is preferably 10 ° to 50 °, more preferably 20 °
It is selected from the range of 〜40 °.

In the reinforcing material layer 5, the smaller the angle of the rectangular linear body 11 is, the closer the extending direction of the braided rectangular linear body 11 becomes to be parallel to the axial direction A of the flexible tube 1. The reinforcing effect of the reinforcing member 12 increases as the extending direction of the rectangular linear body 11 approaches parallel to the axial direction A of the flexible tube 1, and the bending rigidity applied to the reinforcing member layer interposed portion 2 Becomes larger. Therefore, by setting the angle of the rectangular linear body 11 as described above, the bending rigidity of the intermediate region 15 becomes smaller than that of the proximal region 16, and the bending rigidity of the distal region 14 becomes smaller than that of the intermediate region 15. , Reinforcement layer 5
The bending rigidity is further reduced in the distal end portion 7 where no is provided than in the distal end side region 14. In other words, the flexible tube 1 is configured so that the flexibility gradually increases from the base end 9 toward the distal end 7.

In the case of such a configuration, the reinforcing material layer interposition portion 2
When the bending stiffness in the distal region 14 is 1, the bending stiffness in the intermediate region 15 is preferably 1 to 3, more preferably 1.5 to 2.5.
The bending rigidity in the proximal region 16 is preferably 2 to
5, more preferably 3 to 4.

The length of the distal region 14, the intermediate region 15 and the proximal region 16 along the axial direction A is appropriately selected according to the application. For example, the total length of the flexible tube is 110 cm. , The tip side region 14
Is 1 cm to 10 cm, and the length of the intermediate region 15 is 10 cm.
cm to 40 cm, and the length of the proximal region 16 is 50 cm to 8
0 cm.

As described above, the flexible tube 1 of the present invention
Is configured such that the bending rigidity decreases from the base end 9 toward the distal end 7. As described above, the entire structure has moderate flexibility, and particularly has a high flexibility at the distal end portion 7 side. Therefore, when used for a catheter, the stimulation applied to the inner wall of the blood vessel and the like is extremely small, and the blood vessel moves ahead in the blood vessel. It is possible to provide the flexible tube 1 having excellent followability so as to be able to proceed smoothly without damaging the inner wall of the blood vessel along the guide wire. In addition, in the flexible tube 1, the pushing force of the operator in order to penetrate the blood vessel has a proximal end 9 of the flexible tube 1 on the operator's hand side.
And has sufficient bending rigidity over the entire tube 1 so that the rotational force applied at the proximal end 9 can be reliably transmitted to the distal end 7. The configuration on the 9th side has a high bending rigidity. Therefore, it is possible to provide the flexible tube 1 that can exhibit excellent pushability and torque transmission.

As described above, in the present invention, the rectangular linear body 11 having a tensile strength of 500 MPa to 2000 MPa is braided in a net shape. As described above, since the rectangular linear body 11 having a rectangular cross section perpendicular to the extending direction is used as the linear body, a comparison is made with the case where the linear body having a circular cross section is used. Thus, the area in contact with the outer surface 3a of the inner tube 3 having a circular cross section is large, and the linear body can be stably held by the outer surface 3a of the inner tube 3 during braiding. Thus, a regular braided reinforcement 12 with easier braiding
Can be formed. Further, since a material having an appropriate amount of moderate hardness and an appropriate elongation is selected as the rectangular linear body 11, it is easier to braid than when braiding using a conventional hard wire. For this reason, unlike the related art, the rectangular wire 11
It is possible to provide the higher-quality flexible tube 1 including the reinforcing material 12 braided in a regular mesh without disturbing or sagging. As described above, in the flexible tube 1 of the present invention, the braid can be surely braided according to the preset braid state. Therefore, buckling hardly occurs at any portion even when bent or bent so as to be bent, and the tip portion 7 which is liable to buckle in the past.
Since the buckling hardly occurs even in the vicinity, it is possible to provide the flexible tube 1 suitable for a catheter excellent in kink resistance, in which the tube is not easily buckled in a curved or bent portion of the blood vessel even after the guide wire is pulled out, and which is excellent in kink resistance. .

A flexible tube using the rectangular wire 11 has a larger compressive strength in the radial direction than a flexible tube using a round wire having the same diameter as the thickness of the rectangular wire 11. The kink resistance can be improved without increasing the thickness of the reinforcing material layer 5.

In the above embodiment, the distal end of the flexible tube has a structure in which no reinforcing material layer is interposed between the inner pipe and the outer pipe. However, in the present invention, the reinforcing material layer is also provided at the distal end. May be interposed. In such a case, the angle of the rectangular linear body at the distal end with respect to the axial direction A is realized to be larger than the angle θ1 in the distal end region 14.

In the embodiment shown in FIG. 1, the reinforcing material layer interposed portion 2 is divided into three regions, that is, a distal region 14, an intermediate region 15, and a proximal region 16. It is not limited to division into regions, and the base end 9
If the configuration is such that the flexibility increases sequentially from the side toward the distal end portion 7 side, the configuration may be divided into two regions, or the configuration may be divided into four or more regions. You may.

Further, as described above, from the distal end 7 side to the proximal end 9
Although the configuration is such that the bending rigidity increases stepwise toward the side, the present invention is not limited to this, and
A configuration in which the bending rigidity continuously increases from the side toward the base end portion 9 may be employed.

In the flexible tube of the present invention, the bending stiffness basically increases stepwise or continuously from the distal end side to the proximal end side. For example, when the present invention is realized by a flexible tube having a curved portion that bends in the intermediate region in advance, the bending rigidity in the intermediate region is larger than the bending rigidity in the proximal region. It may be formed as follows.

A preferred example of the method for manufacturing the flexible tube 1 of the present invention will be described. First, the core wire is covered with the above-described material of the inner tube 3, and the inner tube 3 is formed on the core wire. As an apparatus used for this coating and forming, for example, 30
mmφ extruder and the like. Examples of the core wire include a SUS wire and a nickel-plated soft copper wire.
S-line is particularly preferably used. After subjecting the inner tube 3 thus formed to a surface treatment using a surface treatment agent,
The rectangular linear body 11 is spirally wound around the outer surface 3a of the inner tube 3. As the surface treatment agent, for example, tetraetch (manufactured by Junkosha) is preferably used. Flat wire 11
As described above, the tensile strength is 500 MPa to 200 MPa.
The one of 0 MPa is used. The winding of the rectangular linear body 11 is performed by a method generally used in this field, for example, by using a device such as a braiding machine. For example, the winding start position of the rectangular linear body 11 is set to the distal end portion 7 and the distal side region 14.
When the rotation speed of the inner tube 3 is constant, the speed of the movement of the inner tube 3 along the axial direction is set to the tip side region 14,
By sequentially increasing the winding positions of the intermediate region 15 and the proximal region 16, the rectangular linear bodies 11 are formed so as to form the angles θ1, θ2, and θ3 as described above.
Can be braided. Thus, the reinforcing member 12 is formed.

Next, a material obtained by winding the rectangular wire 11 around the inner tube 3 including the core wire is made of the material for forming the outer tube 4 described above.
The coating is performed so as to have a predetermined outer diameter R3. As an apparatus used for the coating, for example, a 20 mmφ extruder, a dip coater and the like can be mentioned. The coating is performed such that the inner surface 4a of the outer tube 4 is fixed to the outer surface 3a of the inner tube 3 via the rectangular linear body 11. Further, the above-described fixing is performed by interposing an adhesive such as a urethane adhesive or an epoxy adhesive between the inner surface 4a of the outer tube 4 and the outer surface 3a of the inner tube 3 and the rectangular linear body 11. Is also good. In this way, the outer tube 4 is fixed via the reinforcing material layer 5 so as to be outside the inner tube 3.

As described above, the above-mentioned X-ray contrast agent may be added to the material of the inner tube 3 and / or the outer tube 4. For example, bismuth oxide is added to the material of the outer tube 4 as the X-ray contrast agent. .

Next, annealing is performed using an apparatus such as an air circulation oven, in other words, annealing. Annealing is performed in a temperature range of 80 ° C. to 105 ° C. for 3 hours to 24 hours.

Finally, the core tube is pulled out from the inner tube 3 using a core wire drawing machine or the like, whereby the flexible tube 1 of the present invention can be suitably manufactured.

The above is merely an example of a suitable manufacturing method, and the flexible tube 1 of the present invention does not have to be manufactured by the above manufacturing method.

[0038]

The present invention will be described in detail with reference to the following examples, but the present invention is not limited to the following examples. Example 1 Ten prototypes of the flexible tube 1 having the configuration shown in FIGS. 1 and 2 were manufactured by the above-described manufacturing method. The conditions of each part of the tube 1 are as follows. In addition, the braid of the flat linear body 11 used the microminiature high-speed braid machine. Length of flexible tube 1: 110 cm Length of distal region 14: 10 cm Length of middle region 15: 20 cm Length of proximal region 16: 70 cm Length of distal end 7: 10 cm Inner diameter R1 of inner tube 3 : 1.20 mm Outer diameter R2 of the inner tube 3: 1.28 mm Outer diameter R3 of the outer tube 4: 1.65 mm Constituent material of the inner tube 3: Fluorine resin (tetrafluoroethylene-hexafluoropropylene copolymer (FEP)) ,
Shore D hardness: 60) Constituent material of outer tube 4: Polyurethane resin containing X-ray contrast agent (bismuth oxide) (aliphatic thermoplastic polyurethane elastomer, Shore D hardness: 60) Surface treatment agent of inner tube 3: tetraetch ( Constituent material of the rectangular linear body 11: SUS304 Tensile strength of the rectangular linear body 11: 1420 MPa Width of the rectangular linear body 11: 89 μm Thickness of the rectangular linear body 11: 22 μm Angle θ1: 70 ° Angle θ2: 45 ° Angle θ3: 30 ° Annealing temperature: 80 ° C Annealing time: 16 hours

Example 2 Ten prototypes of flexible tubes were produced in the same manner as in Example 1 except that a rectangular linear body having a tensile strength of 750 MPa was used.

Example 3 Except that a rectangular linear body having a tensile strength of 1920 MPa was used,
In the same manner as in Example 1, the prototype of the flexible tube was
This was produced.

COMPARATIVE EXAMPLE 1 A rectangular wire having a tensile strength of 2190 MPa was used.
In the same manner as in Example 1, the prototype of the flexible tube was
This was produced.

Comparative Example 2 Ten prototypes of flexible tubes were produced in the same manner as in Example 1 except that a rectangular linear body having a tensile strength of 450 MPa was used.

Kink Resistance Test Ten samples of each of the examples and the comparative examples, each of which was prepared, were bent at 160 ° at the center of the tip side region to test whether buckling occurred. When no buckling occurred, it was evaluated as ○, and when buckling was 1/10 or more, it was evaluated as x. Table 1 shows the results.

Bending stiffness test A bending stiffness test was performed according to a test method specified in JIS K7203. The tip side region and the base single side region of each sample were cut to a length of 5 cm, and the load at the time of bending by 2 mm by three-point bending was measured, and this was defined as bending rigidity.
Regarding the tip side region of each sample, when the flexural rigidity was 0.3 N or less, the followability was sufficient, and when it exceeded 0.3 N, the followability was inferior. For the base end region of each sample, if the bending stiffness is 0.6N or more, the indentation and torque transmission are considered to be sufficient. If it is less than 0.6N, the indentation and torque transmission are reduced. Inferior was evaluated as x. The test was performed at a test speed of 1 mm / min, a distance between support points of 30 mm, and a test temperature of 23 ° C. Table 1 shows the results.

[0045]

[Table 1]

[0046]

As is apparent from the above description, according to the present invention, the pushability, the torque transmission property and the followability are excellent, and the braid of the linear body is not disturbed or sagged, and the vicinity of the tip is not affected. However, it is possible to provide a flexible tube that is particularly excellent in kink resistance in which buckling does not easily occur.

[Brief description of the drawings]

FIG. 1 is a side view schematically showing a reinforcing material layer interposed portion 2 of a flexible tube 1 according to a preferred example of the present invention in a partially cut-out state.

2 is an axial direction A of an inner tube 3 of the flexible tube 1 of FIG.
FIG. 3 is a simplified cross-sectional view taken along a cutting plane line II in an imaginary plane perpendicular to FIG.

FIG. 3 is a catheter 6 using the flexible tube 1 of FIG.
It is a figure which shows one preferable example of.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flexible tube 2 Reinforcement layer interposition part 3 Inner tube 4 Outer tube 5 Reinforcement layer 6 Catheter 7 Tip 9 Base end 11 Flat wire body 12 Reinforcement 14 Tip side area 15 Intermediate area 16 Base side area

Claims (3)

[Claims] 1. A reinforcing material layer interposed portion formed by fixing a flexible substantially cylindrical inner tube and an outer tube via a reinforcing material layer such that the inner tube is inside the outer tube. A flexible tube comprising: the reinforcing material layer has a tensile strength of 500 MPa to 2000 MPa.
a) one or a plurality of rectangular wire bodies are braided in a net shape, and the angle formed by each of the rectangular wire bodies with respect to the axial direction of the inner pipe is stepwise or continuous substantially along the axial direction. A flexible tube having a reinforcing material that changes into a flexible tube. 2. The method according to claim 1, wherein an angle formed by each of the rectangular linear bodies with respect to the axial direction of the inner tube changes stepwise or continuously from one end to the other end. The flexible tube according to claim 1, wherein 3. The flexible tube according to claim 1, which is used for a catheter.