JP2002224021A - Flexible tube for endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible tube for an endoscope with excellent chemical resistance. SOLUTION: An inserting part flexible tube 1 is composed of a spiral tube 21, a net-like tube 22 for covering the outer peripheray of the spiral tube 21, skin 3 for covering the outer periphery of the net-like tube 22, and a covering layer 4 for covering the outer periphery of the skin 3. The covering layer 4 is composed mainly of a composite of urethane-based elastomer (an organic material) and silica (an inorganic material). In the composite, a composite domain is formed by joining silica to a hard segment of urethane-based elastomer. The composite has a structure of separating a soft segment of the urethane- based elastomer and the composite domain into two layer. The average thickness of the covering layer 4 is desirably 1 to 100 μm. In the skin 3, a part on the side for contacting with at least the covering layer 4 is desirably composed of a material including urethane-based elastomer.

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 In an endoscopic examination, it is necessary to insert a flexible tube of an endoscope into a body cavity such as a stomach, a duodenum, a small intestine or a large intestine. For this reason, the insertion section flexible tube of the endoscope has an outer skin of the flexible tube for the endoscope, thereby improving the ease of insertion operation (flexibility) and reducing the burden on the patient. In addition, it prevents liquids such as body fluids from entering the inside of the endoscope. Conventionally, an elastic material such as a urethane elastomer has been generally used as a constituent material of the outer cover of the flexible tube for an endoscope.

[0003] Since endoscopes are used repeatedly, they must be cleaned and disinfected each time. However, the conventional materials have poor chemical resistance. For this reason, by repeatedly cleaning and disinfecting the endoscope, the outer cover of the flexible tube deteriorates. Then, the flexibility of the outer skin itself of the flexible tube for an endoscope is reduced, which causes a problem that it becomes difficult to insert the flexible tube into a lumen. Further, when the deterioration is severe, fine cracks or the like are generated, and the constituent material of the outer skin of the flexible tube for an endoscope may be peeled off.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a flexible tube for an endoscope having excellent chemical resistance.

[0005]

This and other objects are achieved by the present invention which is defined below as (1) to (12).

(1) A flexible tube for an endoscope having a coating layer mainly formed of a composite of an organic material and an inorganic material on an outer surface side of an outer skin, wherein the composite is a urethane-based flexible tube. A flexible tube for an endoscope, comprising an elastomer and silica. Thereby, a flexible tube for an endoscope having excellent chemical resistance can be provided.

(2) The composite includes a urethane-based elastomer having a hard segment and a soft segment, and silica, and a composite domain formed by bonding the silica to the hard segment; The flexible tube for an endoscope according to the above (1), wherein the flexible tube has a structure where two layers are separated.

As a result, the chemical resistance of the flexible tube for an endoscope is further improved, and the heat resistance, light resistance, water resistance and the like are also improved.

(3) The above-mentioned (1) or (2), wherein at least a portion of the outer skin on the side in contact with the coating layer is made of a material containing a urethane elastomer.
4. The flexible tube for an endoscope according to claim 1.

[0010] Thereby, the adhesion between the coating layer and the outer skin is particularly excellent, and the elasticity and flexibility of the flexible tube for an endoscope are improved.

(4) The flexible tube for an endoscope according to the above (3), wherein the content of the urethane-based elastomer in a portion of the outer skin in contact with the coating layer is 10 wt% or more.

Thus, the adhesion between the coating layer and the outer skin is particularly excellent, and the elasticity and flexibility of the flexible tube for an endoscope are further improved.

(5) The above-mentioned (1) to (4), wherein at least a portion of the outer skin in contact with the coating layer is made of a material containing an ester elastomer.
The flexible tube for an endoscope according to any one of the above. Thereby, the heat resistance of the flexible tube for an endoscope is improved.

(6) The outer shell according to any one of (1) to (5), wherein at least a part of the outer skin in contact with the coating layer is made of a material containing an olefin-based elastomer. Flexible tube for endoscope.

Thus, the heat resistance of the flexible tube for an endoscope is improved, and the production cost is advantageously reduced.

(7) The flexible tube for an endoscope according to any one of the above (1) to (6), wherein the outer skin has a laminated portion in which a plurality of layers are laminated.

This makes it possible to combine the advantages of the constituent materials of the respective layers constituting the laminate, further improving the characteristics of the flexible tube for an endoscope.

(8) The average thickness of the coating layer is 1 to 1
The flexible tube for an endoscope according to any one of the above (1) to (7), which has a size of 00 μm.

As a result, the chemical resistance can be further improved while maintaining the characteristics of the constituent material of the outer cover.

(9) The endoscope according to any one of (1) to (8), wherein the composite contains 1 to 50 parts by weight of the silica based on 100 parts by weight of the urethane-based elastomer. Flexible tube.

As a result, the adhesion between the outer cover and the coating layer is improved, and the chemical resistance and heat resistance of the flexible tube for an endoscope are further improved.

(10) The composite according to any of the above (1) to (9), which is obtained by reacting a urethane elastomer having an alkoxysilyl group at both terminals with a hydrolyzable alkoxysilane. The flexible tube for an endoscope according to any one of claims 1 to 3. This further improves the chemical resistance, heat resistance, and the like of the flexible tube for an endoscope.

(11) The flexible tube for an endoscope according to the above (10), wherein the hydrolyzable alkoxysilane is tetraalkoxysilane and / or a condensate thereof. This further improves the chemical resistance, heat resistance, and the like of the flexible tube for an endoscope.

(12) The flexible tube for an endoscope according to any one of the above (1) to (11), wherein the coating layer is formed by a coating method.

This makes it possible to easily form a coating layer having a relatively small thickness and a uniform thickness, which is advantageous in reducing the manufacturing cost and the manufacturing time.

[0026]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a flexible tube for an endoscope according to the present invention.

Hereinafter, a preferred embodiment of a flexible tube for an endoscope according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is an overall view showing an electronic endoscope (electronic scope) having an insertion section 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, the electronic endoscope 10 is provided at a flexible insertion tube 1 of a long object having elasticity (flexibility) and at a distal end of the flexible insertion tube 1. Operating section 6 provided at the proximal end of insertion section flexible tube 1, which is gripped by an operator to operate electronic endoscope 10, and connection section connected to 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 user operates the wire 2, the wire (not shown) provided in the insertion portion flexible tube 1 is pulled, and the bending portion 5 is bent in four directions, and the direction can be changed.

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 curved section 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, and the light source processor is further connected to a monitor (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 (not shown). 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, and the like.
, A light guide (not shown) using an optical fiber bundle disposed continuously in the insertion portion flexible tube 1 and the bending portion 5.
Illuminates the observation site from the distal end of the curved portion 5 and illuminates it.

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 portion 5, the insertion portion flexible tube 1, the operation portion 6 and the connection portion flexible tube 7, and the image sensor 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 is an enlarged semi-longitudinal sectional view showing a first embodiment of an insertion portion flexible tube to which the flexible tube for an endoscope of the present invention is applied.

The flexible tube 1 has a core material 2 and an outer skin 3 covering the outer periphery thereof, and a coating layer 4 is further formed on the outer surface side of the outer skin 3. In addition, for example, an instrument such as an optical fiber, an electric cable, a cable or a tube (omitted in the drawing) is disposed inside the flexible tube 1 for insertion.
A space 24 that can be inserted is provided.

The core member 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-shaped 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 thin wires 23 made of metal or nonmetal. 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.

When at least one of the thin wires 23 forming the mesh tube 22 is coated with a synthetic resin, the resin coated on the thin wire 23 is made of a constituent material of the outer cover 3 (at least the inner periphery of the outer cover 3). It is preferable that the material be excellent in compatibility with the surface constituting material). Thereby, the adhesion between the outer cover 3 and the core material 2 is improved. As a result, even when the flexible tube 1 is bent, the outer skin 3 maintains a state of being in close contact with the core material 2 and expands and contracts sufficiently in accordance with the curvature 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 bonding force between the outer cover 3 and the core 2 is strong, the outer cover 3 and the core 2 are less likely to peel off even when the flexible tube 1 is used repeatedly. Therefore, the insertion portion flexible tube 1
Has excellent elasticity even after repeated use, and has excellent durability.

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 inner periphery of the outer cover 3 is in close contact with the core material 2.

A large number of projections (anchors) 31 protruding toward the inner peripheral side are formed on the inner peripheral surface of the outer cover 3 continuously from the outer cover 3. Each protruding portion 31 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 31 that has entered the recess is formed until it reaches the outer periphery of the spiral tube 21. The protruding portion 31 that has entered the hole is formed longer, and its tip enters the space 25 of the spiral tube 21.

Since the projections 31 are formed in this manner, the projections 31 engage with a large number of holes and recesses formed on the outer periphery of the core material 2, so that an anchor effect is produced.
The outer cover 3 is securely fixed to the core 2. 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.

Also, by forming the protruding portion 31,
Since the bonding force between the outer cover 3 and the reticulated tube 22 is strong, the outer cover 3 is less likely to peel 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.

In particular, when the thin wire 23 is coated with a synthetic resin having excellent compatibility with the constituent material of the outer cover 3 (at least the material forming the inner peripheral surface of the outer cover 3), these effects are not obtained. By acting synergistically, the elasticity and durability of the flexible tube 1 become more remarkable.

The constituent material of the outer cover 3 is not particularly limited, but for example, a polyolefin such as polyvinyl chloride, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polyamide, polyethylene terephthalate (PE)
T), polyesters such as polybutylene terephthalate,
Fluorine resins such as polyurethane, polystyrene resin, polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, various flexible resins such as polyimide, urethane elastomer, ester elastomer, olefin elastomer, amide elastomer Elastomer, styrene-based elastomer, fluorine-based elastomer,
One or a combination of two or more of various elastomers such as silicone rubber, fluorine rubber and latex rubber can be used.

It is preferable that at least the portion of the outer skin 3 that contacts the coating layer 4 is made of a material containing a urethane elastomer. Thereby, the coating layer 4
And the adhesion to the outer skin 3 is particularly excellent. Also,
The elasticity and flexibility of the insertion portion flexible tube 1 are further improved. Examples of the urethane-based elastomer include a polyester-based urethane-based elastomer, a polyether-based urethane-based elastomer, and a polycarbonate-based urethane-based elastomer.

The part of the outer skin 3 that is in contact with the coating layer 4 is
When it is made of a material containing a urethane-based elastomer, the content of the urethane-based elastomer in a portion of the outer skin 3 in contact with the coating layer 4 is preferably 10 wt% or more, and more preferably 20 wt% or more. More preferably, it is more preferably at least 40 wt%. As a result, the above-mentioned effect becomes more remarkable.

It is preferable that at least a portion of the outer skin 3 in contact with the coating layer 4 is made of a material containing an ester elastomer. Thereby, the coating layer 4
The heat resistance of the flexible tube 1 can be improved while maintaining the close contact with the flexible tube 1. Examples of the ester elastomer include a polyester / polyether type ester elastomer and a polyester / polyester type ester elastomer.

The portion of the outer skin 3 that comes into contact with the coating layer 4 may be made of an ester elastomer alone, but is preferably made of a material containing an ester elastomer and a urethane elastomer. preferable. In this case, the content of the ester-based elastomer in the portion of the outer skin 3 on the side in contact with the coating layer 4 is preferably 10 wt% or more, and more preferably 60 wt% or more. When the content of the ester-based elastomer in the portion of the outer skin 3 in contact with the coating layer 4 is a value within the above range, the adhesion between the outer skin 3 and the coating layer 4 and the heat resistance of the flexible tube 1 at the insertion portion are provided. However, all of them are particularly excellent.

It is preferable that at least the portion of the outer skin 3 that contacts the coating layer 4 is made of a material containing an olefin-based elastomer. This allows
The heat resistance of the insertion portion flexible tube 1 can be improved while maintaining the adhesion with the coating layer 4. In addition, the insertion portion flexible tube 1
This is also advantageous in reducing the manufacturing cost of the device. Examples of the olefin-based elastomer include a blend-type olefin-based elastomer, a partially cross-linked blend-type olefin-based elastomer, and a completely cross-linked (dynamically cross-linked) blend-type olefin-based elastomer.

The portion of the outer skin 3 in contact with the coating layer 4 may be composed of an olefin elastomer alone, but is preferably composed of a material containing an olefin elastomer and a urethane elastomer. preferable.
In this case, the content of the olefin-based elastomer in the portion of the outer skin 3 in contact with the coating layer 4 is preferably 10 wt% or more, more preferably 20 to 80 wt%. When the content of the olefin-based elastomer in the portion of the outer skin 3 in contact with the coating layer 4 is within the above range, the adhesion between the outer skin 3 and the coating layer 4 and the heat resistance of the insertion portion flexible tube 1 However, all of them are particularly excellent.

Further, the constituent material of the outer cover 3 may optionally contain an additive, if necessary. Examples of the additives include plasticizers, inorganic fillers, pigments, various stabilizers (antioxidants, light stabilizers, antistatic agents, antiblocking agents, lubricants), X-ray contrast agents, and the like.

The constituent materials of the outer cover 3 have been described above. The composition of the constituent materials of the outer cover 3 (mixing ratio of the components) is as follows.
It may be uniform over the entire outer skin 3,
Each part may be different. For example, a material (gradient material) in which the compounding ratio of the contained components changes sequentially in the thickness direction may be used.

The thickness of the outer cover 3 (excluding the protrusion 31)
Is preferably 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 thickness of the outer cover 3 (excluding the protrusion 31)
Can protect the core material 2 and the instruments and the like inserted therein from liquids such as body fluids, and the insertion portion flexible tube 1
It is not particularly limited as long as it does not hinder the curvature of
About 0.08-0.9 mm is preferable, and 0.10-0.
About 8 mm is more preferable.

The coating layer 4 is formed on the outer surface side of the outer cover 3 as described above. The coating layer 4 has a function of improving the chemical resistance of the flexible tube for an endoscope while maintaining characteristics (for example, elasticity, flexibility, and the like) of the outer cover 3.

The coating layer 4 is mainly composed of a composite of an organic material and an inorganic material.
It has a urethane-based elastomer (organic material) and silica (inorganic material).

The composite is not particularly limited as long as it has a urethane-based elastomer (organic material) and silica (inorganic material). For example, a urethane-based composite having an alkoxysilyl group at its terminal (at least one end) can be used. An elastomer (hereinafter, also referred to as "urethane-based elastomer A") and a hydrolyzable alkoxysilane (hereinafter, referred to as "urethane-based elastomer A").
Also called "alkoxysilane A". ) Are preferred.

In such a composite, most of the silica produced by the reaction of the alkoxysilane A (hydrolyzable alkoxysilane) is introduced into the domain of the hard segment of the urethane-based elastomer A to form a composite domain. It has a structure (sea-island structure) in which the domain and the soft segment are separated into two layers. Due to such a two-layer separation structure (sea-island structure), the soft segment of the urethane-based elastomer constituting the matrix of the composite does not contain silica, so that its elasticity and flexibility are maintained as it is, while the hard segment of the urethane-based elastomer is maintained. In this case, only the domain is made tough by the composite domain with silica, and the chemical resistance is particularly excellent. In addition, since the coating layer 4 is mainly composed of such a composite, the flexible tube 1 of the insertion portion has particularly excellent chemical resistance, and also has heat resistance, light resistance, water resistance, and the like. improves.

Hereinafter, the urethane-based elastomer A, the alkoxysilane A, and the composite obtained by reacting them will be described in detail.

The urethane-based elastomer A is, for example, a urethane-based elastomer having any one of functional groups selected from isocyanate group, hydroxyl group and amino group at the terminal (hereinafter, also referred to as "urethane-based elastomer B").
And an alkoxysilane having a functional group capable of reacting with a terminal functional group of the urethane elastomer B (hereinafter, also referred to as “alkoxysilane B”).

The urethane-based elastomer B can be produced, for example, by reacting a polyol component and an organic polyisocyanate compound, and a chain extender with the polyol component and the organic polyisocyanate compound. By adjusting appropriately,
A desired functional group can be introduced at the terminal.

The polyol component forms a soft segment of the urethane-based elastomer and has two hydroxyl groups.
Although various compounds having at least one compound can be used, it is preferable to use a polymer polyol. Examples of the high molecular polyol include polyether polyols such as polymers or copolymers of ethylene oxide, propylene oxide, tetrahydrofuran and the like; ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propane Diol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, octanediol, 1,4-butynediol And various known low-molecular-weight glycols such as dipropylene glycol and the like, alkyl glycidyl ethers such as n-butyl glycidyl ether and 2-ethylhexyl glycidyl ether, glycidyl versatate and the like. Glycidyl carboxylic acid esters, adipic acid, maleic acid, fumaric acid, phthalic anhydride, isophthalic acid, terephthalic acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, azelaic acid, sebacic acid, suberic acid, etc. Polyester polyols obtained by dehydration-condensation of dibasic acids or their corresponding acid anhydrides and dimer acids; Polyester polyols obtained by ring-opening polymerization of cyclic ester compounds; Other polycarbonate polyols, polybutadiene diol , Polyisoprene diols, polychloroprene diols, hydrides of polybutadiene glycol, polyolefin diols such as hydrides of polyisoprene glycol, and glycols obtained by adding ethylene oxide or propylene oxide to bisphenol A. Obtained by polymerizing various radically polymerizable unsaturated monomers such as alkyl (meth) acrylates in the presence of a chain transfer agent having one or more chain transfer groups such as two or more hydroxyl groups and mercapto groups. Examples include macromonomers such as polymers, polyalkoxysilanes such as polydimethylsiloxane, castor oil polyol, and chlorinated polypropylene polyol. Among such high molecular polyols, it is preferable to use polyester polyols. Incidentally, the number average molecular weight of these high molecular polyols is preferably preferably 1500 or more,
More preferably, it is 2000 or more. Further, the number average molecular weight is preferably 6000 or less.

The organic polyisocyanate compound forms a hard segment of the urethane elastomer. Examples of the organic polyisocyanate compound include various compounds such as a linear aliphatic polyisocyanate, a cycloaliphatic polyisocyanate, an aromatic polyisocyanate, an araliphatic polyisocyanate, and a polyisocyanate obtained from an amino acid derivative.

Specific examples of the linear aliphatic diisocyanate include methylene diisocyanate, isopropylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and 2,4,4-diisocyanate. Trimethylhexamethylene diisocyanate, dimer isocyanate in which the carboxyl group of the dimer acid is replaced with an isocyanate group, and the like. Specific examples of the cycloaliphatic diisocyanate include cyclohexane-
Examples thereof include 1,4-diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-di (isocyanatomethyl) cyclohexane, and methylcyclohexane diisocyanate. As specific examples of the aromatic diisocyanate,
Dialkyldiphenylmethane diisocyanate such as 4,4'-diphenyldimethylmethane diisocyanate;
Tetraalkyldiphenylmethane diisocyanate such as 4,4'-diphenyltetramethylmethane diisocyanate, 1,5-naphthylene diisocyanate, 4,4 '
-Diphenylmethane diisocyanate, 4,4'-dibenzyl isocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4
-Tolylene diisocyanate, 2,6-tolylene diisocyanate and the like. Specific examples of the araliphatic diisocyanate include xylylene diisocyanate, m
-Tetramethylxylylene diisocyanate. Specific examples of the diisocyanate obtained from the amino acid derivative include lysine diisocyanate.

The chain extender usually has 2 carbon atoms.
It is preferred to use up to about 6 low molecular polyols and / or low molecular polyamines. Low-molecular polyols include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol,
3-propanediol, 1,3-butanediol, 1,
4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1,5-pentanediol,
Low molecular weight glycols such as 1,6-hexanediol; trihydric alcohols such as glycerin, butanetriol, pentanetriol, hexanetriol, trimethylolethane, and trimethylolpropane; and tetrahydric or higher alcohols such as pentaerythritol and sorbitol. Can be Examples of low molecular weight polyamines include amine compounds such as ethylenediamine, propylenediamine, hexamethylenediamine, triethylenetetramine, diethylenetriamine, isophoronediamine, dicyclohexylmethane-4,4′-diamine; 2-hydroxyethylethylenediamine, 2-hydroxyethyl Propylenediamine, di-2-hydroxyethylethylenediamine, di-
Examples thereof include diamine compounds having a hydroxyl group such as 2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, and di-2-hydroxypropylethylenediamine. These chain extenders are preferably 20% by weight or less of the total amount of the hydrophobic polymer diol and the organic polyisocyanate compound, and 15% by weight or less.
It is more preferable that:

The urethane elastomer B can be obtained, for example, by reacting a polymer polyol with an organic polyisocyanate compound and, if necessary, a chain extender. For the reaction, a general urethane-based elastomer production method can be adopted, and in addition to batch charging, when a chain extender is used, a urethane prepolymer method in which a polymer polyol and an organic polyisocyanate compound are previously reacted can also be adopted. . Further, by appropriately adjusting the amount of each component used, any one of an isocyanate group, a hydroxyl group and an amino group can be introduced into the terminal of the urethane elastomer B.

The urethane elastomer B thus obtained preferably has a number average molecular weight of about 1,800 to 100,000.

The alkoxysilane B to be reacted with the urethane-based elastomer B is
Those having a functional group corresponding to the terminal functional group are appropriately selected and used. That is, urethane elastomer B
When the terminal functional group of is a isocyanate group, an alkoxysilane B having a hydroxyl group and / or an amino group is used. When the terminal functional group of the urethane elastomer B is a hydroxyl group or an amino group, As the silane B, one having an isocyanate group can be used.

Examples of the alkoxysilane having an amino group (alkoxysilane B) include, for example, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyldimethylethoxysilane,
3-aminopropylmethyldiethoxysilane, 4-aminobutyltriethoxysilane, 3-aminopropyltris (trimethylsiloxy) silane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N-
(2-aminoethyl) -3-aminopropylmethyldiethoxysilane, N- (6-aminohexyl) -aminopropyltrimethoxysilane, 3- (m-aminophenoxy) propyltrimethoxysilane, aminophenyltrimethoxysilane, etc. Is mentioned.

Examples of the alkoxysilane having an isocyanate group (alkoxysilane B) include 3-isocyanatopropyltriethoxysilane, 3-isocyanatopropylmonomethyldiethoxysilane, and 3-isocyanatopropyldimethylethoxysilane. .

In the present invention, urethane-based elastomer A is a urethane-based elastomer having an isocyanate group at the end (urethane-based elastomer B) and an alkoxysilane having an amino group (alkoxysilane B). It is preferable to use those reacted.

As the alkoxysilane A, those generally used in the sol-gel method can be used. For example, the general ^{_{formula: R 1 n Si (OR 2}} ) in _4-n (wherein, n represents an integer of 0 to 2, R ¹ is a lower alkyl group which may have a functional group directly bonded to a carbon atom, An aryl group, an unsaturated aliphatic residue, which may be the same or different, and R ² represents a hydrogen atom or a lower alkyl group), or a partial condensate thereof. The lower alkyl group refers to a linear or branched alkyl group having 6 or less carbon atoms.

Specific examples of such alkoxysilane A (hydrolyzable alkoxysilane) include tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane and tetrabutoxysilane; Trimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, isopropyltrimethoxysilane, isopropyltrimethoxysilane Ethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-meth Trialkoxysilanes such as captopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3,4-epoxycyclohexylethyltrimethoxysilane, and 3,4-epoxycyclohexylethyltrimethoxysilane , Dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane or partial condensates thereof. Among these, tetraalkoxysilanes or partial condensates thereof (hereinafter, also simply referred to as “tetraalkoxysilanes”) are preferable. By using a tetraalkoxysilane as the alkoxysilane A, the affinity between the domain formed by the hard segment of the urethane-based elastomer (urethane-based elastomer A) and the alkoxysilane A is particularly excellent. As a result, the obtained composite has particularly excellent chemical resistance, heat resistance and the like. Further, among tetraalkoxysilanes, particularly, tetramethoxysilane, tetraethoxysilane or a partial condensate thereof is preferable.

When the silica formed by condensation of alkoxysilane A (hydrolyzable alkoxysilane) exceeds the total amount of domains formed by the hard segments of the urethane-based elastomer (urethane-based elastomer A), the silica is applied to the coating layer 4. In this case, cohesion, precipitation, and phase separation may occur, and the adhesion between the coating layer 4 and the outer cover 3 may be reduced. For this reason, the amount of the alkoxysilane A to be used when producing the composite is preferably about 1 to 50 parts by weight, in terms of silica to be produced, based on 100 parts by weight of the urethane-based elastomer, and is preferably 3 to 30 parts by weight. It is more preferred to be parts by weight. When the relative content of silica is within the above range, the adhesion between the outer cover 3 and the coating layer 4 is improved, and the chemical resistance, heat resistance, and the like of the flexible tube 1 are further improved.

The coating layer 4 is mainly composed of the above-described composite, but may optionally contain additives as necessary. As additives, for example, plasticizers, inorganic fillers, pigments, various stabilizers (antioxidants,
Light stabilizer, antistatic agent, antiblocking agent, lubricant),
X-ray contrast agents and the like.

Although the constituent materials of the coating layer 4 have been described above, the composition of the constituent materials of the coating layer 4 (the mixing ratio of the contained components) is described.
May be uniform over the entire coating layer 4 or may be different at each site.

The average thickness of the coating layer 4 is not particularly limited, but is preferably, for example, 1 to 100 μm,
More preferably, it is 80 μm.

When the average thickness of the coating layer 4 is within the above range, the chemical resistance can be further improved while sufficiently maintaining the properties of the constituent material of the outer cover 3. Further, at least a part of the coating layer 4 may be integrated with the outer skin 3.

The flexible tube 1 of the insertion part of the present embodiment as described above is manufactured, for example, as follows.

First, a spiral tube 21 and a mesh tube 22 are prepared. The spiral tube 21 can be obtained, for example, by preparing a plate material and subjecting it to a turning process. Further, the mesh tube 22 can be obtained by braiding the fine wire 23.

The helical tube 21 and the mesh tube 22 thus obtained are assembled to produce the core material 2. Then, core material 2
The outer skin 3 is formed on the outer periphery of the.

The outer skin 3 can be formed, for example, by coating the constituent material of the outer skin 3 on the core material 2 by extrusion molding.

The constituent material of the outer cover 3 is obtained by melting or softening the above-mentioned components, mixing and kneading. For melting or softening, mixing and kneading the components, for example, a kneader, a kneader-ruder, a roll, a kneading machine such as a continuous kneading extruder and the like can be used. When each component is kneaded using such a kneading machine, the material is a material in which each component is uniformly mixed.

The kneading temperature is not particularly limited.
For example, it is preferably about 160 to 220 ° C.
It is more preferably about 80 to 210 ° C,
The temperature is more preferably about 205 ° C. When each component is kneaded in such a temperature range, the uniformity of each component in the material is improved.

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 moldability of the outer tube 3 of the flexible tube 1 for insertion. Therefore, the uniformity of the thickness of the outer cover 3 is improved.

Thereafter, the coating tube 4 is formed on the outer surface of the outer cover 3 to obtain the flexible tube 1 at the insertion portion.

Examples of the method for forming the coating layer 4 include various coating methods such as dipping, doctor blade, spin coating, brush coating, spray coating, and roll coater.
Extrusion molding, two-color molding and the like can be mentioned. Among these, the method of forming the coating layer 4 is preferably a method using various coating methods.

According to such a coating method, it is relatively thin,
The coating layer 4 having a uniform thickness can be formed very easily. It is also advantageous for reducing the manufacturing cost and manufacturing time of the flexible tube 1 for insertion.

The coating of the coating layer 4 may be performed, for example, by fitting the coating layer 4 formed in a tube shape to the outer surface of the outer cover 3.

The coating layer 4 can be formed by coating the constituent material of the coating layer 4 containing the above-mentioned composite, and the composition containing the urethane-based elastomer A and the alkoxysilane A (coating) The composition can also be formed by coating the outer layer 3 with the layer forming composition) and reacting the composition on the outer layer 3 to form a complex.

In forming the coating layer 4,
The constituent material of the coating layer 4 containing the composite or the composition may be coated on the outer cover 3 as it is. For example, a solution in which these are dissolved in a solvent capable of dissolving them may be used.

As the solvent used for preparing the solution, for example, a solvent containing water enough to dissolve the urethane-based elastomer A and the alkoxysilane A and to allow hydrolysis of the alkoxysilane A to be used is used. Can be. Examples of the solvent include aromatic solvents such as benzene, toluene and xylene; ester solvents such as ethyl acetate and butyl acetate; methanol, ethanol,
Alcohol solvents such as isopropanol and n-butanol; acetone, methyl ethyl ketone, diethyl ketone,
Solvents containing at least one of ketone solvents such as methyl isobutyl ketone; amide solvents such as dimethylformamide; sulfoxide solvents such as dimethyl sulfoxide; ether solvents such as dimethyl ether and diethyl ether. Usually, the solid content concentration in the solution is about 10 to 40% by weight.

The composition may contain, for example, a curing catalyst that promotes the hydrolysis and condensation of alkoxysilane A (hydrolyzable alkoxysilane) and promotes the curing reaction of the composition. Good.

As such a curing catalyst, for example, formic acid,
Organic acid catalysts such as acetic acid, propionic acid, p-toluenesulfonic acid, and methanesulfonic acid; inorganic acid catalysts such as boric acid and phosphoric acid; and alkaline catalysts, among others, are particularly preferable.

By using an organic acid catalyst as the curing catalyst, the tendency of silica to be guided to the domain formed by the hard segments of the urethane-based elastomer A is increased.

In addition, when alkoxysilane A (hydrolyzable alkoxysilane) is hydrolyzed with an organic acid catalyst, silanol residues are increased, and the hydrogen bonding interaction with the hard segment of urethane elastomer A is reduced. Become stronger.

Among these organic acid catalysts, formic acid, acetic acid,
Paratoluenesulfonic acid is particularly preferred.

The curing catalyst may be used in a so-called catalytic amount. That is, the amount of the catalyst used can be appropriately determined depending on the activity of the catalyst used. Usually, the molar ratio to the used alkoxysilane A (hydrolyzable alkoxysilane) is adjusted to 0.1 with paratoluenesulfonic acid having a high catalytic ability.
About 001 to 5 mol%, for example, about 0.01 to 50 mol% of formic acid, acetic acid or the like having a low catalytic ability is used. The timing of addition of the curing catalyst is not particularly limited. When a solvent-free composition is prepared from the urethane-based elastomer A and the alkoxysilane A, the solution composition is prepared by dissolving the urethane-based elastomer A and the alkoxysilane A in a solvent. May be added at the time of preparation. Alternatively, the composition may be added after coating the outer skin 3.

In the constituent material of the coating layer 4 containing the composite or in the composition, a viscosity modifier, a plasticizer, an antibacterial agent, a fungicide, a leveling agent may be used as long as the effects of the present invention are not impaired. Various organic and inorganic additives such as a defoaming agent, a colorant, a stabilizer, a curing catalyst, and a solvent for adjusting the solubility can be added as necessary. In addition, it is a matter of course that commonly used components can be used in various applications.

FIG. 3 is an enlarged semi-longitudinal sectional view showing a second embodiment of the flexible tube at the insertion portion to which the flexible tube for an endoscope of the present invention is applied. Hereinafter, the insertion portion flexible tube 1 shown in FIG. 3 will be described focusing on differences from the first embodiment, and the description of the same items will be omitted.

In the flexible tube 1 of the insertion portion according to the second embodiment, the outer skin 3 is formed of a laminate having an inner layer 32, an intermediate layer 33, and an outer layer 34.

[0108] As described below, the outer skin 3 is
2. One of the intermediate layer 33 and the outer layer 34 is made of a material having different physical characteristics or chemical characteristics from those of the other layers. Examples of physical properties include rigidity (elasticity), hardness, elongation, tensile strength, shear strength, flexural modulus, flexural strength, and the like.
Chemical properties include, for example, chemical resistance, weather resistance, and the like. Note that these are merely examples, and the present invention is not limited to these.

The inner layer 32 is formed on the innermost side of the outer skin 3 and is in close contact with the core material 2. Therefore, it is preferable to select a material having excellent adhesion to the core material 2 as a constituent material of the inner layer 32. The inner layer 32 is formed of a material that can form the protrusion 31 by controlling the size (length), shape, number, and the like of the protrusions 31 to be appropriate. Is preferred. When the inner layer 32 is made of such a material, the elasticity and durability of the flexible tube 1 can be controlled.

The constituent material of the inner 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,
Fluorine resins such as polyurethane, polystyrene resin, polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, various flexible resins such as polyimide, urethane elastomer, ester elastomer, olefin elastomer, amide elastomer Elastomer, styrene-based elastomer, fluorine-based elastomer,
One or a combination of two or more of various elastomers such as silicone rubber, fluorine rubber and latex rubber can be used.

Of these, urethane-based elastomers, olefin-based elastomers, and ester-based elastomers are particularly preferred because the formation of the projections 31 is easily controlled.

Although the thickness of the inner layer 32 (excluding the portion of the protruding portion 31) is not particularly limited, it is usually 0.03 to 0.03.
It is preferably about 0.8 mm, more preferably about 0.03 to 0.4 mm.

The intermediate layer 33 is formed on the outer peripheral surface of the inner layer 32. The intermediate layer 33 is preferably a layer having better elasticity than an outer layer 34 described later. This allows
The intermediate layer 33 exhibits a cushion function between the inner layer 32 and the outer layer 34. The intermediate layer 33 is preferably a layer that is more flexible than the inner layer 32.

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 32 and the outer layer 34 having relatively high hardness, the restoring force of the intermediate layer 33 is efficiently transmitted to the inner layer 32 and the outer layer 34. For this reason, almost all of the restoring force of the intermediate layer 33 is utilized for restoring the bending of the flexible tube 1 at the insertion portion. 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 copolymers, various flexible resins such as polyimides, urethane elastomers, One or a combination of two or more of various elastomers such as an ester elastomer, an olefin elastomer, an amide elastomer, a styrene elastomer, a fluorine elastomer, a silicone rubber, a fluorine rubber, and a latex rubber can be used.

Of these, urethane-based elastomers, olefin-based elastomers, and ester-based elastomers having low hardness are particularly preferred because of their excellent elasticity.

The thickness of the intermediate layer 33 is not particularly limited, but is usually preferably about 0.02 to 0.8 mm.
It is more preferably about 0.02 to 0.4 mm.

The outer layer 34 is formed on the outermost side of the outer skin 3. The outer layer 34 is made of the same material as the constituent material of the outer cover 3 of the first embodiment described above. However, in the present embodiment, as described above, the inner layer 32 having excellent adhesion to the core material 2 and the intermediate layer 33 having excellent elasticity are provided.
Is provided, the physical properties of the outer skin 3 are
It does not depend solely on the physical properties of. Therefore,
Even if the outer layer 34 is relatively hard, sufficient elasticity can be obtained as the entire outer skin 3.

Although the thickness of the outer layer 34 is not particularly limited,
Usually, about 0.03 to 0.8 mm is preferable,
It is more preferably about 3 to 0.4 mm.

It should be noted that the outer cover 3 may have a laminated portion in which such a plurality of layers are laminated over its entire length, or may have at least a part thereof.

As described above, by forming the outer cover 3 as a laminate of a plurality of layers, the advantages of the material constituting each layer can be obtained.

The flexible tube 1 of the present embodiment can be manufactured in the same manner as the flexible tube 1 of the first embodiment described above. By simultaneously extruding the constituent material of the inner layer 32, the constituent material of the intermediate layer 33, and the constituent material of the outer layer 33 using a machine, and covering the laminated body on the core material 2, the outer skin 3 having a laminated structure is continuously formed. Can be formed. Thereby, the productivity of the flexible tube 1 can be improved. Also,
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.

The flexible tube for an endoscope according to the present invention has been described above, but the present invention is not limited to these.

For example, in the second embodiment, the outer skin 3
Is composed of three layers, the inner layer 32, the intermediate layer 33, and the outer layer 34, but may be composed of two layers (for example, the inner layer 32 and the outer layer 34 in which the intermediate layer 33 is omitted). ,
It may be composed of four or more layers.

As a method of 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.

Further, the flexible tube for an endoscope of the present invention can be applied to, for example, a flexible tube at a connection portion connected to a light source processor.

[0127]

Next, specific examples of the present invention will be described.

1. Production of Flexible Tube for Endoscope (Example 1) First, a 3.2 mm wide stainless steel strip was wound to produce a spiral tube 21 having an outer diameter of 9 mm and an inner diameter of 7 mm. Next, a braided tube was prepared by braiding 10 stainless steel thin wires each having a diameter of 0.08 mm. The spiral tube was covered with this mesh tube to obtain a core material.

Next, the outer periphery of the core material was covered with an outer cover material by extrusion molding to form an outer cover (average thickness: 0.4 mm).

As the outer shell material, a urethane elastomer (TPU) in the form of pellets kneaded at 195 ° C. for 20 minutes was used. In addition, the temperature of the shell material during extrusion molding was 200 ° C.

Thereafter, a solution for forming a coating layer was applied to the outer surface of the outer skin by brushing to form a coating layer, and a flexible tube for an endoscope having a length of 1.5 m was produced.

As the solution for forming the coating layer, a solution prepared as described below was used.

First, a polyester polyol (trade name: Clapol P2010, manufactured by Kuraray Co., Ltd.), number average molecular weight: 2,000, adipic acid and 3-methyl -1,5-
Polyester polyol composed of pentanediol): 148 parts and polyester polyol (trade name:
Praxel 220 (manufactured by Daicel Chemical Industries, Ltd.), number average molecular weight: 2000, polyester polyol composed of adipic acid, ε-caprolactone, and neopentyl glycol: 222 parts, and isophorone diisocyanate:
102.7 parts was reacted at 80 ° C. for 5 hours under a nitrogen stream to obtain an isocyanate-terminated urethane prepolymer (urethane-based elastomer B).

Then, 383 parts of toluene and 383 g of methyl ethyl ketone were added to the system, and 5
After cooling to 0 ° C., 38.8 parts of isophoronediamine and 27.2 parts of 3-aminopropyltriethoxysilane (alkoxysilane B) were added to 2-propanol: 38
The solution dissolved in 3 parts was added dropwise over 10 minutes, and then reacted at the same temperature for 1 hour. Thus, the number average molecular weight: about 1
A urethane-based elastomer (urethane-based elastomer A) solution of 7000, solid content: 30% was obtained.

The urethane-based elastomer (urethane-based elastomer A) solution thus obtained: 100 parts,
4. Partial condensate of tetramethoxysilane (alkoxysilane A) (trade name: MS51 (manufactured by Tama Chemical Co., Ltd.)):
88 parts, 10% aqueous solution of p-toluenesulfonic acid: 0.1
g was mixed to prepare a coating layer forming solution.

The average thickness (dry film thickness) of the coating layer formed by applying the coating layer forming solution thus prepared was 10 μm.

Example 2 The average thickness of the coating layer was 20 μm.
A flexible tube for an endoscope was produced in the same manner as in Example 1 except for the above.

(Example 3) As a constituent material of the outer cover, a urethane elastomer (TPU) in the form of pellets: 40 parts by weight and an olefin elastomer (TP) in the form of pellets were used.
O): A flexible tube for an endoscope was produced in the same manner as in Example 1 except that kneaded 60 parts by weight at 195 ° C. for 20 minutes.

Example 4 The average thickness of the coating layer was 20 μm.
A flexible tube for an endoscope was produced in the same manner as in Example 3 except that the above procedure was adopted.

(Example 5) As a constituent material of the outer skin, a urethane elastomer (TPU) in the form of pellets: 60 parts by weight and an olefin elastomer (TP) in the form of pellets were used.
O): A flexible tube for an endoscope was produced in the same manner as in Example 1 except that 40 parts by weight and kneaded at 195 ° C. for 20 minutes were used.

Example 6 The average thickness of the coating layer was 20 μm.
A flexible tube for an endoscope was produced in the same manner as in Example 5 except that the above procedure was adopted.

(Example 7) As a constituent material of the outer skin, a pellet-type ester-based elastomer (TPEE) was used.
A flexible tube for an endoscope was produced in the same manner as in Example 1 except that the mixture kneaded at 5 ° C. for 20 minutes was used.

Example 8 The average thickness of the coating layer was 20 μm.
A flexible tube for an endoscope was produced in the same manner as in Example 7 except that the above procedure was adopted.

(Example 9) As the constituent materials of the outer cover, a urethane elastomer (TPU) in the form of pellets: 50 parts by weight and an ester elastomer (TPE) in the form of pellets were used.
E): A flexible tube for an endoscope was prepared in the same manner as in Example 1 except that kneaded with 50 parts by weight at 195 ° C. for 20 minutes.

Example 10 The average thickness of the coating layer was 20 μm.
A flexible tube for an endoscope was produced in the same manner as in Example 9 except that m was used.

(Example 11) A flexible tube for an endoscope was produced in the same manner as in Example 1 except that the outer skin formed on the outer periphery of the core material was a laminate comprising an inner layer, an intermediate layer and an outer layer. Was prepared. In addition, the formation of the laminated body was performed using the extrusion molding machine provided with three extrusion ports. That is, the constituent material of the inner layer,
The constituent material of the intermediate layer and the constituent material of the outer layer were simultaneously extruded, and the laminated body was coated on a core material to continuously produce an outer skin having a laminated structure.

As the constituent material of the inner layer, the constituent material of the intermediate layer, and the constituent material of the outer layer, a pellet-type ester-based elastomer (TPEE) was used at 195 ° C. for 20 minutes.
Kneaded at 195 ° C. for 20 minutes, and pelletized urethane-based elastomer (TPU) at 195 ° C. for 195 minutes.
A mixture kneaded at 20 ° C for 20 minutes was used. Further, the temperature of the constituent material of the inner layer, the constituent material of the intermediate layer, and the constituent material of the outer layer during extrusion molding were all 200 ° C. The thicknesses of the inner layer, the intermediate layer, and the outer layer thus formed were 0.15 mm, 0.1 mm, and 0.15 mm, respectively.

(Comparative Example 1) A flexible tube for an endoscope was produced in the same manner as in Example 1 except that no coating layer was formed on the outer surface of the outer skin of the flexible tube for an endoscope. .

Comparative Example 2 The procedure of Example 1 was repeated, except that a copolymer of an aliphatic urethane polymer and a silicone resin (urethane-silicone copolymer) was used as a constituent material of the coating layer. A flexible tube for an endoscope was manufactured.

Comparative Example 3 The average thickness of the coating layer was 20 μm.
A flexible tube for an endoscope was produced in the same manner as in Comparative Example 2 except that the above was used.

In each of Examples and Comparative Examples, TPU, TPO and TPEE used as constituent materials of the outer skin are shown below.

TPU: Polyester-based urethane elastomer (product name: Resamine P-1045 (manufactured by Dainichi Seika Kogyo Co., Ltd.)) TPO: Sumitomo TPE 3572 (manufactured by Sumitomo Chemical Co., Ltd.) TPEE: polyester- Polyether type ester elastomer (Product name: Hytrel 3046 (Toray)
(Dupont Co., Ltd.))

Table 1 summarizes the constituent materials of the outer shell (in Example 11, the inner layer, the intermediate layer, and the outer layer), the constituent materials of the coating layer, and the average thickness for each of the examples and comparative examples.

[0154]

[Table 1]

[0155] 2. Evaluation of characteristics of flexible tube for endoscope [2.1] Elasticity test The flexible tube for endoscope produced in each of Examples and Comparative Examples was subjected to an elasticity test by the following method.

In the elasticity test, ten flexible tubes for each endoscope were prepared, and it was examined whether or not a bundle of these tubes could be folded together.

After bundling ten flexible tubes for each endoscope, a bending operation was performed, and the evaluation was performed according to the following four-grade criteria.

◎: Rich in elasticity. ：: elastic. Δ: Poor elasticity. X: Almost no elasticity (cured state).

[2.2] Chemical resistance test A chemical resistance test was performed on the flexible tube for an endoscope manufactured in each of Examples and Comparative Examples by the following method.

In the chemical resistance test, a warming type washing machine (trade name: SME2000 (manufactured by BHT)) was used.
A cleaning and disinfecting operation was performed on each flexible tube for an endoscope.

The washing / disinfecting operation includes a washing step (about 10 minutes) using a washing liquid (nonionic surfactant).
Disinfectant (about 0.24 wt% glutaraldehyde aqueous solution)
The process consists of four steps: a disinfection step (approximately 10 minutes), a water washing step using about 60 ° C. hot water (about 10 minutes), and a drying step using warm air (about 5 minutes).

After the washing / disinfecting operation was repeated 2,000 times, the surface condition of the flexible tube for an endoscope was observed and evaluated according to the following four criteria.

A: No change in appearance. ：: Almost no fading or yellowing is observed. Δ: Slight fading and yellowing are slightly observed. X: Gloss and yellowing are clearly recognized.

Further, the adhesion between the outer skin and the coating layer was examined for each of the flexible tubes for endoscopes in which the washing / disinfection operation was repeated 2000 times. The adhesion between the outer skin and the coating layer was measured using a cloth impregnated with ethanol, and each flexible tube for endoscope was 100
The state of the outer surface of the flexible tube for an endoscope at the time of rubbing was examined and evaluated according to the following four-grade criteria.

：: No flaw was observed on the outer surface of the flexible tube for an endoscope. ：: Slight scratches are observed on the outer surface of the flexible tube for endoscope. Δ: Slight peeling of the coating layer from the outer skin was observed. ×: Peeling of the coating layer from the outer skin is clearly observed. Table 2 shows the results.

[0166]

[Table 2]

As is clear from Table 2, the flexible tubes for endoscopes of the present invention all had excellent elasticity and chemical resistance.

On the other hand, the flexible tube for an endoscope of the comparative example is
The elasticity was excellent, but the chemical resistance was poor.

[0169]

As described above, according to the present invention, it is possible to obtain a flexible tube for an endoscope which is excellent in chemical resistance while utilizing the characteristics of the constituent material of the outer cover (particularly elasticity and flexibility). be able to.

In the case where the outer skin is a laminate in which a plurality of layers are laminated, the material of each layer is selected and the thickness and the like are appropriately set, and the advantage of the material constituting each layer is determined by the combination of the characteristics of each layer. As a result, various performances required for the flexible tube for an endoscope can be simultaneously improved.

[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 a first embodiment of an insertion portion flexible tube to which the flexible tube for an endoscope of the present invention is applied.

FIG. 3 is an enlarged semi-longitudinal sectional view showing a second embodiment of an insertion portion flexible tube to which the flexible tube for an endoscope 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 Projection 32 Inner layer 33 Intermediate layer 34 Outer layer 4 Coating layer 5 Bending part 6 Operating part 61, 62 Operation knob 7 Connecting part flexible tube 8 Light source insertion part 81 Light source connector 82 Image signal connector 10 Electronic endoscope

Claims (12)

[Claims] 1. An endoscope flexible tube having a coating layer mainly composed of a composite of an organic material and an inorganic material on an outer surface side of an outer skin, wherein the composite is a urethane-based elastomer. And flexible silica for an endoscope, comprising: 2. The composite, comprising: a urethane-based elastomer having a hard segment and a soft segment; and silica; a composite domain formed by bonding the silica to the hard segment; The flexible tube for an endoscope according to claim 1, wherein the flexible tube has a structure in which two layers are separated. 3. The flexible tube for an endoscope according to claim 1, wherein the outer skin is made of a material containing a urethane-based elastomer at least on a side in contact with the coating layer. 4. The urethane-based elastomer content in a portion of the outer skin that is in contact with the coating layer is 1
The flexible tube for an endoscope according to claim 3, wherein the content is 0 wt% or more. 5. The endoscope according to claim 1, wherein at least a portion of the outer skin that is in contact with the coating layer is made of a material containing an ester-based elastomer. Flexible tube. 6. The endoscope according to any one of claims 1 to 5, wherein at least a portion of the outer skin that is in contact with the coating layer is made of a material containing an olefin-based elastomer. Flexible tube. 7. The flexible tube for an endoscope according to claim 1, wherein the outer skin has a laminated portion in which a plurality of layers are laminated. 8. An average thickness of the coating layer is 1 to 100 μm.
The flexible tube for an endoscope according to any one of claims 1 to 7, wherein m is m. 9. The flexible tube for an endoscope according to claim 1, wherein the composite contains 1 to 50 parts by weight of the silica based on 100 parts by weight of the urethane-based elastomer. . 10. The composite according to claim 1, wherein the composite is obtained by reacting a urethane-based elastomer having an alkoxysilyl group at both terminals with a hydrolyzable alkoxysilane. Flexible tube for endoscope. 11. The hydrolyzable alkoxysilane,
The flexible tube for an endoscope according to claim 10, which is a tetraalkoxysilane and / or a condensate thereof. 12. The flexible tube for an endoscope according to claim 1, wherein the coating layer is formed by a coating method.