JP2001314368A - Flexible tube for endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible tube for an endoscope having various types of performances required for the tube for the endoscope and to particularly provide the flexible tube for the endoscope having excellent chemical resistance, springiness and durability. SOLUTION: The flexible tube 1 for an inserting part comprises a spiral tube 21, a net-like tube 22 covering an outer periphery of the tube 21, and an outer coat 3 covering an outer periphery of the tube 22. The coat 3 is constituted of a laminate having an inner layer 31, an outer layer 32 and an intermediate layer 33. Many protrusions 4 are formed on an inner peripheral surface of the layer 31. The layer 31 is preferably constituted of a material easy to control formations of the protrusions 4. The layer 32 is preferably constituted of a material having a chemical resistance. The layer 33 is formed between the layer 31 and the layer 32. The layer 33 is preferably formed as a more flexible (excellent springiness) layer than the layer 32.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible tube for an endoscope.

[0002]

2. Description of the Related Art A flexible tube for an endoscope has a structure in which a tubular core material in which the outer periphery of a spiral tube is covered with a mesh tube is covered with a sheath made of synthetic resin or the like.

In endoscopy, a flexible tube for an endoscope is inserted while being bent deep into a body cavity such as the stomach, duodenum, small intestine or large intestine. For good operability at the time of insertion, the pushing force applied at the proximal end (hand side) of the flexible tube for an endoscope must be reliably transmitted to the distal end. Conversely, the endoscope tends to be in a state (buckling state) in which the pushing force applied on the proximal end side of the flexible tube for an endoscope is absorbed by the bent portion of the flexible tube for an endoscope. Flexible tube has poor operability. In order to make the flexible tube for an endoscope hard to buckle, the flexible tube for an endoscope needs to have excellent elasticity to bending. In addition, since buckling is likely to occur at a portion where the outer skin has peeled off from the core material, the outer skin and the core material need to be in close contact with each other.

Further, in order to improve the operability at the time of insertion, when a twist (rotation) is applied at the proximal end side (hand side) of the flexible tube for an endoscope, this rotation is performed. It is also necessary that the distal end portion surely rotates along with the proximal end side without being absorbed in the middle. For this reason, the flexible tube for an endoscope needs to be excellent in followability of the distal end portion to the rotation on the proximal end side.

In order to improve the resiliency of the flexible tube for an endoscope, the outer tube of the flexible tube for an endoscope has a two-layer structure of an outer layer and an inner layer, and the outer layer is made of a flexible material and the inner layer is made of an elastic material. A flexible tube for an endoscope made of a material having good spontaneity is disclosed in Japanese Examined Patent Publication No. 5-50287.

However, in the above-mentioned prior art, the adhesion (coupling force) between the outer skin and the core material is not taken into consideration. The elasticity and buckling resistance of the pipe sometimes decreased. That is, there is a problem in durability of the flexible tube for an endoscope.

Further, the endoscope needs to be cleaned and disinfected each time it is used. In the prior art, since the chemical resistance of the outer skin is not taken into account, there is a risk that deterioration may progress due to repeated disinfection, fine cracks or the like may occur, or the outer skin may peel off from the core material.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a flexible tube for an endoscope which has various performances required for a flexible tube for an endoscope. An object of the present invention is to provide a flexible tube for an endoscope excellent in performance and durability.

[0009]

This and other objects are achieved by the present invention which is defined below as (1) to (15).

(1) A flexible tube for an endoscope having a tubular core material and an outer skin coated on the outer periphery of the core material, wherein the outer skin is an inner layer, an outer layer, and a space between them. A flexible tube for an endoscope, comprising: a portion constituted by a laminate having at least one intermediate layer positioned thereon. This allows
Each layer can be provided with its own characteristics, and a flexible tube for an endoscope having excellent chemical resistance, elasticity and durability can be provided.

(2) The flexible tube for an endoscope according to the above (1), wherein the core material has a large number of holes and / or concave portions on its outer periphery. Thereby, elasticity and durability are further improved.

(3) The core material includes a spiral tube formed by spirally winding a band-shaped material, and a braided body that is formed by braiding a thin wire, which is coated on the outer periphery of the spiral tube and braided. The flexible tube for an endoscope according to (2). This gives you elasticity,
The durability is further improved.

(4) The flexible tube for an endoscope according to the above (2) or (3), wherein a projection portion which has entered the hole and / or the concave portion of the core material is formed continuously from the inner layer. .
Thereby, elasticity and durability are further improved.

(5) At least one of the fine wires forming the braided body is coated with a synthetic resin, and at least a part of the coating layer is melted and bonded to the inner layer. Or the flexible tube for endoscopes according to (4). Thereby, elasticity and durability are further improved.

(6) The flexible tube for an endoscope according to the above (5), wherein the inner layer contains a material having high compatibility with a synthetic resin constituting the coating layer. This gives you elasticity,
The durability is further improved.

(7) The flexible tube for an endoscope according to any one of the above (1) to (6), wherein the thickness of the laminate is substantially constant along the longitudinal direction. Thereby, the operability of insertion is further improved, and the burden on the patient is further reduced.

(8) Any one of the inner layer, the outer layer, and the intermediate layer is made of a material having a physical property or a chemical property different from those of the other one. The flexible tube for an endoscope according to any one of (1) to (7). Thereby, at least one of chemical resistance, elasticity, and durability is further improved.

(9) The flexible tube for an endoscope according to any one of the above (1) to (8), wherein the outer layer is made of a material having excellent chemical resistance. Thereby, chemical resistance is further improved.

(10) The flexible tube for an endoscope according to any one of the above (1) to (9), wherein the intermediate layer is a layer softer than the outer layer. Thereby, the elasticity is further improved.

(11) The outer layer is a layer whose hardness is higher than the hardness of the inner layer and the intermediate layer.
The flexible tube for an endoscope according to any one of (10) to (10). Thereby, chemical resistance and durability are further improved.

(12) The flexible tube for an endoscope according to any one of the above (1) to (11), wherein the intermediate layer has a cushioning function between the outer layer and the inner layer. Thereby, the elasticity is further improved.

(13) At least one of the inner layer, the outer layer, and the intermediate layer is formed of a polyurethane elastomer, a polyester elastomer, a polyolefin elastomer, a polystyrene elastomer, a polyamide elastomer, a fluorine elastomer, and a fluorine rubber. The flexible tube for an endoscope according to any one of the above (1) to (12), which is made of a material containing at least one selected from the group consisting of: Thereby, at least one of chemical resistance, elasticity, and durability is further improved.

(14) The inner layer, the outer layer, and the intermediate layer are each selected from the group consisting of a polyurethane elastomer, a polyester elastomer, a polyolefin elastomer, a polystyrene elastomer, a polyamide elastomer, a fluorine elastomer, and a fluorine rubber. The flexible tube for an endoscope according to any one of the above (1) to (13), wherein the flexible tube is made of a material containing at least one of the following. Thereby, chemical resistance, elasticity, and durability are further improved.

(15) The flexible tube for an endoscope according to any one of the above (1) to (14), wherein the outer skin is coated on an outer periphery of the core material by extrusion molding. Thereby, a flexible tube for an endoscope can be manufactured with good productivity and preferably.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a flexible tube for an endoscope according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is an overall view showing an electronic endoscope (electronic scope) having an insertion portion flexible tube to which the flexible tube for an endoscope of the present invention is applied. Hereinafter, in FIG. 1, the upper side will be described as a “base end” and the lower side as a “distal end”.

As shown in FIG. 1, an electronic endoscope 10 is provided at a flexible insertion portion flexible tube 1 having a long length and having a distal end portion. Operating section 6 provided at the proximal end of the flexible tube 1, the insertion section flexible tube 1 and held by an operator to operate the entire electronic endoscope 10, and a connecting section connected to the operating section 6. The flexible tube 7 includes a flexible tube 7 and a light source insertion portion 8 provided on a distal end side of the flexible tube 7.

The flexible tube 1 is used by inserting it into a lumen of a living body. The operation unit 6 is provided with operation knobs 61 and 62 on its side surface. These operation knobs 61 and 6
When the operator operates the wire 2, the wire (not shown) disposed in the insertion portion flexible tube 1 is pulled, so that the bending tube 5 bends in four directions and can change its direction.

An image pickup device (CCD) (not shown) for picking up an image of a subject at an observation site is provided at the distal end of the bending tube 5, and an image signal connector 82 is provided at the distal end of the light source insertion section 8. Have been. The image signal connector 82 is connected to a light source processor (not shown),
Further, the light source processor device is connected to a monitor device (not shown) via a cable.

A light source connector 81 is provided at the end of the light source insertion portion 8, and the light source connector 81 is connected to a light source processor. The light emitted from the light source processor device is transmitted to the light source connector 81, the light source insertion portion 8, the connection portion flexible tube 7, the operation portion 6, the insertion portion flexible tube 1, and the bending tube 5. The light passes through a light guide (not shown) composed of optical fiber bundles arranged continuously, and is irradiated onto the observation site from the distal end of the curved tube 5 and illuminated.

The reflected light (subject image) from the observation site illuminated by the illumination light is picked up by an image pickup device. The image sensor outputs an image signal corresponding to the captured subject image.

This image signal is continuously arranged in the bending tube 5, the insertion portion flexible tube 1, the operation portion 6, and the connection portion flexible tube 7, and the image element and the image signal connector 82 Is transmitted to the light source insertion unit 8 via an image signal cable (not shown) for connecting.

Then, predetermined processing (for example, signal processing, image processing, and the like) is performed in the light source insertion unit 8 and the light source processor, and then input to the monitor. In the monitor device, an image (electronic image) captured by the image sensor,
That is, an endoscope monitor image of a moving image is displayed.

The overall configuration of the electronic endoscope 10 having the flexible insertion tube 1 to which the flexible tube for an endoscope of the present invention is applied has been described above. Needless to say, the present invention can be applied to a flexible tube of a fiber endoscope.

FIG. 2 shows the flexible tube 1 at the insertion portion of the electronic endoscope 10.
FIG. The insertion portion flexible tube 1 is made of a core material 2
And an outer skin 3 covering the outer periphery thereof. Also,
The insertion section flexible tube 1 is provided with a space 24 in which instruments and the like (omitted in the drawing) such as an optical fiber, an electric cable, a cable or a tube can be arranged and inserted.

The core 2 is composed of a spiral tube 21 and a braided tube (braided body) 22 that covers the outer periphery of the spiral tube 21, and is formed as a tube-like long object as a whole. The core material 2 has an effect of reinforcing the insertion portion flexible tube 1. In particular, by combining the spiral tube 21 and the mesh tube 22,
The insertion portion flexible tube 1 can ensure sufficient mechanical strength.

The spiral tube 21 is formed by spirally winding a belt-like material with a uniform diameter at an interval 25. As a material constituting the belt-like material, for example, stainless steel, a copper alloy, or the like is preferably used.

The mesh tube 22 is formed by braiding a plurality of metal or nonmetal thin wires 23 arranged. As a material constituting the fine wire 23, for example, stainless steel, a copper alloy, or the like is preferably used. Also, the mesh tube 22
May be coated with a synthetic resin (not shown) on at least one of the fine wires 23 forming the pattern.

On the outer periphery of the braided tube 22, a braided thin wire 2
A gap 26 is formed by the third stitch. The gap 26 becomes a concave portion at a position overlapping the outer periphery of the spiral tube 21, and a hole communicating with the space 24 at a position overlapping the interval 25 of the spiral tube 21, and forms a large number of holes and concave portions on the outer periphery of the core material 2. are doing.

The outer periphery of the core material 2 is covered with an outer skin 3. The outer cover 3 is formed of a laminate having an inner layer 31, an outer layer 32, and an intermediate layer 33.

As will be described below, the outer skin 3 is
1, one of the outer layer 32 and the intermediate layer 33 is made of a material having different physical characteristics or chemical characteristics from those of the other one layer. Physical properties include, for example, rigidity (flexibility), hardness, elongation, tensile strength, shear strength, flexural modulus, flexural strength, and the like. Chemical properties include, for example, chemical resistance And weather resistance. Note that these are merely examples, and the present invention is not limited to these.

The inner layer 31 is formed on the innermost side of the outer skin 3 and is in close contact with the core material 2.

On the inner peripheral surface of the inner layer 31, a number of projections (anchors) 4 protruding toward the inner peripheral side are formed continuously from the inner layer 31. Each protruding portion 4 enters each of a large number of holes and concave portions formed on the outer periphery of the core material 2. The tip of the protrusion 4 that has entered the recess is a spiral tube 2
1 until it reaches the outer circumference. The protruding portion 4 that has entered the hole is formed longer, and its tip enters the space 25 of the spiral tube 21.

The inner layer 31 has a size (length) of the protrusion 4,
It is preferable that the projection 4 be formed of a material that can form the protruding portion 4 by controlling the shape, the number, and the like to be appropriate.

Since the projecting portion 4 is formed as described above, the projecting portion 4 engages with a large number of holes and concave portions formed on the outer periphery of the core member 2, so that an anchor effect is generated, and The outer skin 3 is securely fixed with respect to. Therefore, even when the flexible tube 1 is bent, the outer skin 3 is kept in close contact with the core material 2 and expands and contracts sufficiently in accordance with the bending of the core material 2. The restoring force of the outer skin 3 greatly expanded and contracted in this way is strongly exerted, and greatly contributes to the force for restoring the bending of the insertion portion flexible tube 1. Therefore, with such a configuration, the flexible insertion section 1 is excellent in elasticity.

Further, since the projecting portion 4 has a strong bonding force between the outer cover 3 and the reticulated tube 22, the outer cover 3 hardly peels off from the reticulated tube 22 even when used repeatedly. Therefore, the flexible tube 1 has excellent elasticity even after repeated use, and is excellent in durability.

When at least one of the thin wires 23 forming the mesh tube 22 is coated with a synthetic resin, at least a part of the coated resin (coating layer) is melted to form an inner layer. 31 (bonded).

By forming the constituent material of the inner layer 31 to include a material having excellent compatibility with the synthetic resin coated on the fine wire 23, the coating layer of the fine wire 23 is sufficiently bonded to the inner layer 31.

As described above, the coating layer of the fine wire 23 is
In the case where the outer shell 3 and the core material 2 are bonded together, the bonding strength between the outer skin 3 and the core material 2 is higher. In addition, the flexible insertion tube 1 has better elasticity and durability.

The constituent material of the inner layer 31 is not particularly limited. For example, polyolefin such as polyvinyl chloride, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polyamide, polyethylene terephthalate (PE)
T), polyesters such as polybutylene terephthalate,
Polyurethane, polystyrene resin, polytetrafluoroethylene, fluorine-based resin such as ethylene-tetrafluoroethylene copolymer, various flexible resins such as polyimide, polyurethane-based elastomer, polyester-based elastomer, polyolefin-based elastomer, polyamide-based One or a combination of two or more of various elastomers such as an elastomer, a polystyrene-based elastomer, a fluorine-based elastomer, a silicone rubber, a fluorine rubber, and a latex rubber can be used.

Of these, polyurethane elastomers, polyolefin elastomers, and polyester elastomers are particularly easy to control the formation of the protruding portions 4.
preferable.

The thickness of the inner layer 31 (excluding the portion of the protrusion 4) is not particularly limited, but is usually 0.05 to
It is preferably about 0.8 mm, and more preferably about 0.05 to 0.4 mm.

The outer layer 32 is formed on the outermost side of the outer skin 3. The outer layer 32 is preferably made of a material having chemical resistance. Thereby, even if the washing and disinfection are repeatedly performed, the outer skin 3 is hardly deteriorated, and the outer skin 3 hardens, and the flexibility is reduced, and the outer skin 3 is hardly peeled off from the mesh tube 22 due to cracks or the like.

The hardness of the outer layer 32 is set relatively high. The hardness of the outer layer 32 is preferably higher than the hardness of the inner layer 31 and the intermediate layer 33. Thereby, even if it is repeatedly used, the surface of the outer cover 3 is not easily scratched, and is less likely to cause a crack or the like.

Here, usually, when the hardness of the outer layer 32 is made relatively high in consideration of chemical resistance and resistance to scratching, the flexibility and elasticity of the insertion portion flexible tube 1 are reduced. It may decrease. On the other hand, in the present invention, there is no such a possibility by providing the flexible intermediate layer 33 as described later.

The constituent material of the outer layer 32 is not particularly limited. For example, polyolefin such as polyvinyl chloride, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polyamide, polyethylene terephthalate (PE)
T), polyesters such as polybutylene terephthalate,
Polyurethane, polystyrene resin, polytetrafluoroethylene, fluorine-based resin such as ethylene-tetrafluoroethylene copolymer, various flexible resins such as polyimide, polyurethane-based elastomer, polyester-based elastomer, polyolefin-based elastomer, polyamide-based One or a combination of two or more of various elastomers such as an elastomer, a polystyrene-based elastomer, a fluorine-based elastomer, a silicone rubber, a fluorine rubber, and a latex rubber can be used.

Among these, in particular, polyolefins such as ethylene-vinyl acetate copolymer, fluorine resins such as polytetrafluoroethylene and ethylene-tetrafluoroethylene copolymer, polyolefin elastomers, fluorine elastomers, silicone rubber, fluorine rubber Rubber is preferable because of its excellent chemical resistance.

The thickness of the outer layer 32 is not particularly limited.
Usually, it is preferably about 0.05 to 0.8 mm, and 0.0
It is more preferably about 5 to 0.4 mm.

The intermediate layer 33 is formed between the inner layer 31 and the outer layer 32. It is preferable that the intermediate layer 33 be a layer that is more flexible (excellent in elasticity) than the outer layer 32. Thus, the intermediate layer 33 exhibits a cushion function between the inner layer 31 and the outer layer 32. Further, the intermediate layer 33 includes the inner layer 31.
Preferably, the layer is more flexible.

The cushion function of the intermediate layer 33 will be described in more detail. When the flexible tube 1 is bent, the elasticity of the intermediate layer 33 is excellent, so that the deformed intermediate layer 33 exerts a strong restoring force. And the middle layer 3
Since 3 is sandwiched between the inner layer 31 and the outer layer 32 having relatively high hardness, the restoring force of the intermediate layer 33 is efficiently transmitted to the inner layer 31 and the outer layer 32. Therefore, almost all of the restoring force of the intermediate layer 33 is used for restoring the bending of the insertion portion flexible tube 1. Therefore, by adopting such a configuration, the flexible tube 1 is excellent in elasticity.

The constituent material of the intermediate layer 33 is not particularly limited. For example, polyolefin such as polyvinyl chloride, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polyamide, polyethylene terephthalate (P
ET), polyesters such as polybutylene terephthalate, polyurethanes, polystyrene resins, polytetrafluoroethylene, fluorine resins such as ethylene-tetrafluoroethylene copolymer, various flexible resins such as polyimides, polyurethane elastomers, Among various elastomers such as polyester elastomer, polyolefin elastomer, polyamide elastomer, polystyrene elastomer, fluorine elastomer, silicone rubber, fluorine rubber, latex rubber, etc.
Species or a combination of two or more can be used.

Of these, polyurethane elastomers, polyolefin elastomers and polyester elastomers having low hardness are particularly preferred because of their excellent flexibility (elasticity).

In this embodiment, the intermediate layer 33 has a single-layer structure, but may have a structure in which two or more intermediate layers 33 are formed.

The thickness of the intermediate layer 33 is not particularly limited, but is usually preferably about 0.05 to 0.8 mm.
It is more preferably about 0.05 to 0.4 mm.

It is preferable that the entire thickness of the outer cover 3 (excluding the protrusion 4) is substantially constant along the longitudinal direction. Thereby, the operability when inserting the flexible tube 1 into the body cavity is further improved, and the burden on the patient is further reduced.

The overall thickness of the outer cover 3 (excluding the protruding portion 4) can protect the core member 2 and instruments and the like inserted therein from liquids such as bodily fluids, and can be inserted into the insertion portion. There is no particular limitation as long as the flexibility of the flexible tube 1 is not hindered. Usually, it is preferably about 0.15 to 0.9 mm, and 0.3 to 0.9 mm.
It is more preferably about 0.8 mm.

The method of manufacturing the flexible tube for an endoscope as described above is not particularly limited. However, it can be manufactured continuously by coating the core 2 with the core 2 by extrusion molding. According to the extruder having a plurality of extrusion ports, the inner layer 31, the outer layer 32 and the intermediate layer 33 are simultaneously extruded,
The laminate can be coated on the core material 2. Further, the thickness of each layer can be adjusted by adjusting the discharge amount of the constituent material of each layer from each extrusion port and the pulling speed of the core material 2.

The material temperature during extrusion molding is not particularly limited, but is preferably, for example, about 130 to 220 ° C., and more preferably about 165 to 205 ° C. If the material temperature during extrusion is in such a temperature range,
The material is excellent in formability of the outer cover 3. Therefore, the uniformity of the thickness of the outer cover 3 is improved.

Although the flexible tube for an endoscope of the present invention has been described above, the present invention is not limited to these.

For example, as a method for manufacturing a flexible tube for an endoscope, first, the outer cover 3 is formed as a continuous long object,
A method is also possible in which the core material 2 is inserted into the inner cavity of the outer skin 3 and then tightly fixed by heating or the like.

The flexible tube for an endoscope of the present invention is not limited to the one whose outer skin is constituted by a laminate as described above over the entire length, and the outer skin is partially formed in the longitudinal direction as described above. It may be composed of a laminate having the above configuration.

The flexible tube for an endoscope of the present invention can be applied to, for example, a light guide flexible tube.

[0073]

The present invention will now be described by way of Examples and Comparative Examples.
This will be described in more detail.

1. Production of Flexible Tube for Endoscope (Example 1) First, a stainless steel strip having a width of 3 mm was wound to produce a spiral tube 21 having an outer diameter of 9.9 mm and an inner diameter of 9.6 mm. Next, a braided tube 22 was prepared by braiding the ten thin stainless steel wires 23 each having a diameter of 0.1 mm. One of the fine wires 23 was coated with a polyamide resin. This mesh tube 2
2 was used to cover the helical tube 21 to obtain a core material 2.

Next, on the outer periphery of the core material 2 by extrusion molding,
An outer skin 3 composed of three layers of an inner layer 31, an outer layer 32, and an intermediate layer 33 was covered to produce a 1.6 m long flexible tube for an endoscope.

Example 2 A flexible tube for an endoscope was produced in the same manner as in Example 1 except that the thickness of the inner layer 31 was changed.

(Example 3) A flexible tube for an endoscope was manufactured in the same manner as in Example 1 except that the thickness of the intermediate layer 33 was changed.

Example 4 A flexible tube for an endoscope was produced in the same manner as in Example 1 except that the material and thickness of the outer layer 32 were changed.

Example 5 A flexible tube for an endoscope was produced in the same manner as in Example 1 except that the material of the outer layer 32 was changed.

Outer skin 3 in endoscope flexible tube of each embodiment
Table 1 shows the constituent materials and thicknesses of the respective layers.

The longitudinal sections of the flexible tubes for endoscopes of Examples 1 to 5 were as shown in FIG.

(Comparative Examples 1 to 4) Core 2 similar to that of Example 1
Of the inner layer 31 and the outer layer 32 by extrusion molding
A flexible tube for an endoscope having a length of 1.6 m was produced by coating the outer skin composed of the layers.

Outer skin 3 in flexible tube for endoscope of each comparative example
Table 1 shows the constituent materials and thicknesses of the respective layers.

When the longitudinal sections of the flexible tube for an endoscope of each comparative example are observed, in Comparative Examples 1, 2 and 4, as in Examples 1 to 5, as shown in FIG. Projection 4
However, in Comparative Example 3, the protrusion 4 was not formed.

2. Evaluation of characteristics of flexible tube for endoscope [2.1] Chemical resistance test A chemical resistance test was performed on each flexible tube for endoscope produced in each of Examples and Comparative Examples.

The flexible tube for an endoscope produced in each of the examples and comparative examples was placed in a 10% aqueous iodine solution 1 maintained at 25 ° C.
Each was immersed in 00L for 200 hours.

In the chemical resistance test, two flexible tubes for each endoscope were used.
The state after 00 hours was evaluated according to the following four-grade criteria. A: No change in appearance. No cracking and lifting of the hull. ：: Almost no change in appearance. Slight lifting of outer skin. Δ: It can be seen that the appearance was deteriorated. Floating of outer skin occurs in various places. ×: Deterioration of appearance can be clearly recognized. Cracks and lifting of the outer skin occurred remarkably. Table 1 shows the results of the chemical resistance test.

[2.2] Elasticity test An elasticity test was performed on each flexible tube for an endoscope produced in each of the examples and comparative examples.

In the elasticity test, an operation was performed in which both ends of each flexible tube for an endoscope were supported and bent at 90 °, and the elasticity at that time was evaluated according to the following four criteria. ◎: Very excellent elasticity, ideal for use as a flexible tube for endoscopes. ：: Excellent elasticity, suitable for use as a flexible tube for an endoscope. Δ: The elasticity was somewhat poor, and there was a problem in use as a flexible tube for an endoscope. X: Poor elasticity, not suitable for use as a flexible tube for an endoscope. Table 1 shows the results of the elasticity test.

[2.3] Durability Test A durability test was performed on each flexible tube for an endoscope produced in each of the examples and comparative examples.

The durability was determined by repeating the operation of bending both ends of each flexible tube for endoscopes at 90 °, 300 times, and then examining the elasticity by the same method as the elasticity test. The evaluation was made according to the degree of decrease in elasticity before and after the evaluation, and was evaluated according to the following four-step criteria. ：: The elasticity was hardly changed, and the durability was very excellent. ：: The elasticity is slightly reduced and the durability is excellent. Δ: The elasticity was reduced as clearly seen, and there was a problem in durability. X: The elasticity was remarkably reduced, and deterioration was confirmed at various places. Table 1 shows the results of the durability test.

[0092]

[Table 1]

The materials A to D in Table 1 are as follows. Material A: Medium hardness polyurethane elastomer (JIS
81) Material B: Low hardness polyurethane elastomer (JIS)
Hardness according to K 7311 68) Material C: High hardness polyester elastomer (JIS
Hardness according to K 7311 92) Material D: High hardness polyolefin-based elastomer (JIS
Material E: High hardness polyurethane-based elastomer (JIS)
Hardness by K 7311 92) From the results shown in Table 1, it became clear that the flexible tube for an endoscope of the example is excellent in all of chemical resistance, elasticity and durability.

On the other hand, the flexible tube for an endoscope of Comparative Example 1 was inferior in chemical resistance probably because the material of the outer layer 32 was poor in chemical resistance.

The flexible tube for an endoscope of Comparative Example 2 was inferior in elasticity probably because both the inner layer 31 and the outer layer 32 were made of a material having relatively high hardness.

The flexible tube for an endoscope of Comparative Example 3 was inferior in elasticity and durability probably because the protruding portion 4 was not formed in the inner layer 31.

The flexible tube for an endoscope of Comparative Example 4 was inferior in durability because the inner layer 31 was made of a material having a relatively low hardness and the strength of the projection 4 was low.

[0098]

As described above, according to the present invention, in each layer of the laminated body constituting the outer skin, selection of a material, setting of thickness, etc. are appropriately performed, and an endoscope is obtained by combining the characteristics of each layer. Various performances required for the flexible tube for a mirror can be simultaneously improved.

In particular, by selecting the material of the outer layer, it is possible to make the flexible tube for an endoscope excellent in chemical resistance.

Further, by using a flexible material for the intermediate layer, the flexible tube for an endoscope can be made to have excellent elasticity.

By using a material having high adhesion to the core material for the inner layer, the endoscope flexible tube can be made to have excellent durability.

Further, as described above, it is possible to provide these excellent performances.

[Brief description of the drawings]

FIG. 1 is an overall view showing an electronic endoscope having an insertion portion flexible tube to which the endoscope flexible tube of the present invention is applied.

FIG. 2 is an enlarged semi-longitudinal sectional view showing an embodiment of an insertion portion flexible tube to which the endoscope flexible tube of the present invention is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insertion part flexible tube 2 Core material 21 Spiral tube 22 Reticulated tube 23 Fine wire 24 Space 25 Interval 26 Gap 3 Outer skin 31 Inner layer 32 Outer layer 33 Intermediate layer 4 Projection part 5 Curved tube 6 Operation part 61, 62 Operation knob 7 Connection possible Flexible tube 8 Light source insertion part 81 Light source connector 82 Image signal connector 10 Electronic endoscope

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tadashi Kasai 2-36-9 Maenocho, Itabashi-ku, Tokyo Asahi Gaku Kogyo Co., Ltd. (72) Inventor Hideo Namba 2-36-9 Maenocho, Itabashi-ku, Tokyo No. Asahi Gaku Kogyo Co., Ltd. F-term (reference) 2H040 BA00 DA03 DA15 DA16 GA02 3H111 AA02 BA12 BA15 CA03 CB06 CB24 CC02 DA26 DB10 DB21 EA04 4C061 DD03 FF26 JJ03

Claims (15)

[Claims] 1. A flexible tube for an endoscope having a tubular core material and an outer skin covered on the outer periphery of the core material, wherein the outer skin is located between an inner layer, an outer layer, and the outer layer. A flexible tube for an endoscope, comprising: a portion constituted by a laminate having at least one intermediate layer. 2. The flexible tube for an endoscope according to claim 1, wherein the core material has a large number of holes and / or recesses on an outer periphery thereof. 3. The core material includes: a spiral tube formed by spirally winding a strip-shaped material; and a braided body formed by braiding a thin wire and covering the outer periphery of the spiral tube. 3. The flexible tube for an endoscope according to 2. 4. The flexible tube for an endoscope according to claim 2, wherein a protruding portion that has entered the hole and / or the concave portion of the core material is formed continuously from the inner layer. 5. A synthetic resin coating is applied to at least one of the thin wires forming the braided body, and at least a part of the coating layer is melted and bonded to the inner layer. 4. The flexible tube for an endoscope according to claim 1. 6. The flexible tube for an endoscope according to claim 5, wherein the inner layer contains a material having high compatibility with a synthetic resin constituting the coating layer. 7. The flexible tube for an endoscope according to claim 1, wherein the thickness of the laminate is substantially constant along a longitudinal direction. 8. The semiconductor device according to claim 1, wherein one of the inner layer, the outer layer, and the intermediate layer is made of a material having a physical property or a chemical property different from that of any one of the other layers. 8. The flexible tube for an endoscope according to any one of items 7 to 7. 9. The flexible tube for an endoscope according to claim 1, wherein the outer layer is made of a material having excellent chemical resistance. 10. The flexible tube for an endoscope according to claim 1, wherein the intermediate layer is a layer that is more flexible than the outer layer. 11. The outer layer is a layer whose hardness is higher than the hardness of the inner layer and the intermediate layer.
0. The flexible tube for an endoscope according to any one of [1] to [10]. 12. The flexible tube for an endoscope according to claim 1, wherein the intermediate layer has a cushioning function between the outer layer and the inner layer. 13. At least one of said inner layer, said outer layer and said intermediate layer comprises a polyurethane elastomer, a polyester elastomer, a polyolefin elastomer, a polystyrene elastomer, a polyamide elastomer, a fluorine elastomer and a fluorine rubber. The flexible tube for an endoscope according to claim 1, wherein the flexible tube is made of a material containing at least one selected from the group. 14. The inner layer, the outer layer, and the intermediate layer each include a polyurethane elastomer, a polyester elastomer, and a polyolefin elastomer,
14. The flexible tube for an endoscope according to claim 1, wherein the flexible tube is made of a material containing at least one selected from the group consisting of a polystyrene elastomer, a polyamide elastomer, a fluorine elastomer, and a fluorine rubber. . 15. The flexible tube for an endoscope according to claim 1, wherein the outer cover is formed by coating the outer periphery of the core material by extrusion molding.