JP2000116787A - Tube for medical treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tube for medical treatment which allows the coating of the surface of a metallic tube with a smooth resin tube having a uniform thickness without subjecting the tubes to a heat treatment of high temperature. SOLUTION: A resin is previously molded to a tubular form and this tube is swollen by an organic solvent to increase the bore of the resin tube 13, following which the metallic tube 12 is inserted therein and the solvent is dried to shrink the resin tube 13. The resin tube is thus deposited on the outer periphery of the metallic tube 12. A metallic tube consisting of a superelastic material is preferably used as the metallic tube 12. The metallic tube may also be a metallic tube imparted with flexibility by forming grooves 14 at its front end or may be a mesh-like tube. The front end 13a of the resin tube 13 is preferably projected from the front end 12a of the metallic tube 12. Further, the surface of the resin tube 13 may be coated with a hydrophilic resin film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medical tube such as a catheter in which a resin tube is coated around a metal tube.

[0002]

2. Description of the Related Art In recent years, for examination and treatment of tubular organs of the human body such as blood vessels, ureters, bile ducts, and trachea, a catheter is inserted to administer a drug such as a contrast medium, or tissue is passed through a catheter with forceps or the like. Some of them are collected.

[0003] In order to prevent the catheter from easily deforming along the insertion path of a blood vessel or the like and not damaging the inner wall of the blood vessel or the like, flexibility and slipperiness, particularly at the distal end portion, and insertion and operability are required. Stiffness at the proximal end is needed to improve Further, pressure resistance is required so as not to expand against internal pressure when injecting a drug or the like.

[0004] The catheter generally comprises a resin tube such as a fluororesin or a urethane resin. However, the resin tube is difficult to be pushed into a body cavity due to insufficient rigidity on the base side. In addition, since the torsional rigidity is insufficient, it is difficult to turn the base side in a desired direction by rotating the base side, and there is a problem that the insertion operation cannot be performed quickly. Further, there is a problem that the pressure is increased due to swelling with respect to the internal pressure when the medicine is injected.

On the other hand, for example, JP-A-8-308933,
Japanese Patent Application Laid-Open No. 8-308934 discloses a catheter or the like having a metal tube having a groove formed at the distal end for imparting flexibility, and a resin tube or a resin film coated on the outer periphery of the metal tube. A medical tube is disclosed. Although these medical tubes are excellent in operability and pressure resistance, it is necessary to cover the outer periphery of the metal tube with a resin tube or a resin film in order to improve the slipperiness.

Hitherto, as a method of coating the surface of a metal tube or the like with a resin, an inner layer made of unfired ethylene tetrafluoride resin, a wound layer of a metal wire, and an outer layer made of unfired ethylene tetrafluoride resin are used. After laminating in order, they are heated to a temperature equal to or higher than the melting point of the tetrafluoroethylene resin to integrate them (Japanese Patent Laid-Open No. 5-95892), an inner layer, a first outer layer, and a reinforcing layer formed therebetween. Is a catheter having a body portion covered with a second outer layer and a distal end portion formed of only a second outer layer, wherein the first outer layer is extruded into an inner layer provided with a reinforcing layer. (JP-A-6-70982).

[0007]

However, in the above method, when the resin is welded and integrated by heating it to a temperature higher than the melting point of the tetrafluoroethylene resin, when a superelastic material is used for the metal tube, The properties are impaired by the heat treatment. Also, in the method of the above, when applying resin, heat is applied for extrusion molding,
In the same manner as described above, there is a disadvantage that the properties of the superelastic material are impaired.

In the extrusion molding, the metal tube is eccentric with respect to the resin tube, which tends to cause uneven thickness. When a spiral groove or the like is formed at the tip of the metal tube, the resin tube enters the groove. Irregularities are formed on the surface,
In some cases, the hydrophilic resin could not be coated well on that portion, and the slipperiness was sometimes impaired. Furthermore, it was difficult to make the tip of the resin tube protrude from the tip of the metal tube.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a resin tube having a smooth and uniform thickness without subjecting a metal tube surface to a high-temperature heat treatment. An object of the present invention is to provide a medical tube that can be covered.

[0010]

In order to achieve the above object, a first aspect of the present invention is to cover a metal tube with a resin tube swollen with an organic solvent and evaporate and dry the organic solvent to form the resin tube. An object of the present invention is to provide a medical tube which is in close contact with the outer periphery of a metal tube.

According to the first aspect, when the resin tube is coated on the metal tube, it is not necessary to heat the resin tube to a high temperature. Therefore, a material whose characteristics change by heat, such as a superelastic material, is used as the metal tube. Also does not impair its properties. Further, since the resin is formed in a tube shape in advance, even if a groove or the like is formed in the lower metal tube, it is possible to cover the resin layer with a smooth and uniform thickness. Further, by adjusting the outer diameter of the metal tube and the inner diameter of the resin tube, a very thin resin coating is possible.

A second aspect of the present invention is the medical tube according to the first aspect, wherein an inner diameter of the resin tube before being swollen with an organic solvent is equal to or smaller than an outer diameter of the metal tube. Is provided.

According to the second aspect of the invention, when the swollen resin tube is covered with the metal tube and dried, the resin tube can be firmly adhered to the outer periphery of the metal tube.

According to a third aspect of the present invention, there is provided a medical tube according to the first or second aspect, wherein the resin tube projects from the tip of the metal tube.

According to the third aspect, since the resin tube protrudes from the metal tube, it is possible to prevent the inner wall from being damaged when the distal end of the medical tube hits the inner wall of the human tubular organ.

In the present invention, it is preferable that the metal tube is made of a superelastic material. In this case, the flexibility of the superelastic material allows the metal tube to be inserted into a tubular organ while maintaining a suitable degree. By adding a high rigidity, the insertion operability can be further improved.

The resin tube is preferably made of polyurethane, in which case it is easy to swell with an organic solvent, and its surface is easily coated with a hydrophilic resin or the like.

Further, it is preferable that the surface of the resin tube is further coated with a hydrophilic resin film, whereby the slipperiness can be improved.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The metal tube used in the present invention is preferably made of a superelastic material, stainless steel or the like, and particularly preferably made of a superelastic material having excellent flexibility. As the superelastic material, Ni-Ti alloy, Cu-Z
n-X (X = Al, Fe, etc.) alloy, Ni-Ti-X (X
= Fe, Cu, V, Co) alloys and the like are preferably used.

It is widely known that the Ni-Ti alloy and the like have a shape memory effect and a superelastic (pseudoelastic) effect as a shape memory alloy, and among them, those having a superelastic (pseudoelastic) effect Is suitable for use as a medical tube because it returns to its original shape without permanent deformation upon unloading even if a deformation strain exceeding the yield point is given, and has a large return characteristic against torsion and bending. It is preferable that the temperature condition for exhibiting the (pseudoelasticity) effect is set to the internal temperature of a human or an animal or lower. For superelasticity (pseudoelasticity),
Reference can be made to JIS H 7001 issued by the Japan Standards Association.

As the metal tube, a metal cylindrical tube is preferably used. However, a mesh tube formed by providing a large number of holes in a metal cylinder or knitting a metal wire rod may be used. Also, at the tip of the metal tube,
For example, a spiral groove may be provided in order to provide sufficient flexibility so as not to damage the inner wall of the tubular organ of the human body. Also, the distal end of the metal tube can be cut obliquely to impart flexibility to the distal end. Further, a metal coil may be fixed to the tip of a normal metal tube.

The metal tube has an outer diameter of 0.3 to 2.0 mm and a wall thickness of 0.04 to 0.1, although it depends on the use of the medical tube, especially when used as a catheter.
mm is preferably used.

The resin tube used in the present invention is not particularly limited as long as it can be swelled by an organic solvent. In particular, a tube made of polyurethane is preferably used. The size of the resin tube is not particularly limited as long as it can swell with an organic solvent and coat the outer periphery of the metal tube and, when the organic solvent is evaporated and dried, can adhere to the outer periphery of the metal tube. In order to increase the inner diameter, it is preferable that the inner diameter before swelling with the organic solvent is equal to or smaller than the outer diameter of the metal tube, and the inner diameter after swelling with the organic solvent is larger than the outer diameter of the metal tube. The thickness of the resin tube is 0.05 to 0.3.
mm is preferably used.

Further, by using a resin tube longer than the entire length of the metal tube to be covered, the tip of the resin tube can protrude a predetermined length from the tip of the metal tube to form a flexible tip made of only resin. preferable.

Examples of the organic solvent for swelling the resin tube used in the present invention include toluene, methylene chloride and methyl ethyl ketone.

In the present invention, when the resin tube is swollen, it is preferable that the resin tube is immersed in the above-mentioned organic solvent at room temperature for 1 minute or more, depending on the thickness of the resin tube.

After the swollen resin tube is coated on the outer periphery of the metal tube, the solvent is preferably evaporated and dried at room temperature for 10 minutes or more, depending on the thickness of the resin tube. More preferably, it is dried for one hour or more. Further, when it is desired to shorten the drying time, the material may be placed in an oven and heated at a temperature at which the properties of the superelastic material are not impaired, or may be air-dried.

Preferably, the surface of the resin tube is further coated with a hydrophilic resin film. As a hydrophilic resin film,
For example, polyurethane, polyether block amide,
Polyethylene, polyvinyl chloride, polyester, polypropylene, polyamide, polystyrene, fluororesin,
Silicon resin or the like is used. Also, the resin tube is
A material containing an X-ray opaque material may be used. As the X-ray opaque material, for example, a powder such as bismuth, barium sulfate, or tungsten is preferably used.

Although the medical tube of the present invention is particularly suitable as a catheter, it can also be applied to a tube for enclosing an optical fiber such as an endoscope.

1 to 3 show one embodiment of a medical tube according to the present invention. 1 is a side view showing a metal tube, FIG. 2 is a cross-sectional view showing a state in which a metal tube is covered with a resin tube swollen with an organic solvent, and FIG. FIG. 3 is a cross-sectional view showing a state in which the tube is in close contact with the outer periphery of the tube.

The metal tube 12 is made of, for example, a superelastic material, and is formed such that the outer periphery of the tip portion is tapered and the wall thickness of the tube is gradually reduced. In this case, the degree of thinning is preferably such that the thickness a at the forefront is 0.2 to 0.8 times the thickness b on the base side (see FIG. 3). Such processing can be performed by an etching method or a centerless polishing method.

A spiral groove 14 penetrating into and out of the tube is formed at the tip of the metal tube 12 to provide flexibility.

The pitch of the spiral groove 14 is gradually narrowed toward the tip, so that the spiral groove 14
The width A on the base side in the coil portion formed by
Is 5 to 20 mm, and the width B on the tip side is 0.1 to 2 mm. The spiral groove 14 can be formed by, for example, a method using etching, a method using mechanical processing, or the like. As the method using mechanical processing, cutting, laser processing, or the like is preferably adopted.

As the resin tube 13, a urethane resin is preferably used, and after swelling with an organic solvent such as toluene, methylene chloride, methyl ethyl ketone, etc., is coated on the outer periphery of the metal tube 12, as shown in the figure. At this time, the length of the resin tube 13 is made longer than the length of the metal tube 12, and the tip 13 a of the resin tube 13 is formed.
Are arranged so as to protrude from the distal end 12 a of the metal tube 12.

In this state, when the organic solvent which swells the resin tube 13 is dried by evaporation, the resin tube 13 contracts and adheres to the outer periphery of the metal tube 12 to obtain the medical tube 11 as shown in FIG. Can be. In addition, the outer periphery of the resin tube 13 may be further coated with a hydrophilic resin film as described above.

When the medical tube 11 is used as a catheter, the outer diameter of the metal tube 12 is preferably 0.4 to 2.0 mm in the state shown in FIG.
The outer diameter of 3 is preferably 0.5 to 2.6 mm. The thickness b of the metal tube 12 on the base side is 0.05 to 0.2.
mm is preferable, and the thickness c of the resin tube 13 is 0.0
5 to 0.3 mm is preferred. Further, the medical tube 11
The overall length is preferably 500 to 2000 mm, and the length D of the distal end provided with the spiral groove 14 in the metal tube 12 and having flexibility is preferably 50 to 600 mm.
Furthermore, the protruding length C of the distal end 13a of the resin tube 13 from the distal end 12a of the metal tube 12 is 2 to 300.
mm is preferred.

FIGS. 4 and 5 show another embodiment of the medical tube according to the present invention. In this embodiment,
The distal end 23 of the metal tube 22 is cut obliquely, thereby providing flexibility.

As shown in FIG. 4, a resin tube 13 swollen with an organic solvent is put on the outer periphery of a metal tube 22.
Next, by evaporating and drying the organic solvent, the resin tube 13 is brought into close contact with the outer periphery of the metal tube 22 as shown in FIG. At this time, the resin tube 13 covers the obliquely cut distal end portion 23 of the metal tube 22 in a tubular shape, prevents the distal end portion 23 from being exposed, and secures an internal passage of the medical tube 21.

FIG. 6 shows another embodiment of the medical tube obtained by the present invention. In the medical tube 31, a mesh tube formed by knitting a metal wire is used as the metal tube 32. After being swollen with an organic solvent, the resin tube 13 is covered on the outer periphery of the metal tube 32 of a mesh, and is evaporated and dried on the outer periphery of the metal tube 32 by evaporating the organic solvent.

In the present invention, as the metal tube, a simple tube whose tip is not processed may be used.

[0041]

EXAMPLE As a metal tube, a tube made of a superelastic material having an outer diameter of 0.5 mm, an inner diameter of 0.38 mm, and a length of 1500 mm was cut at an oblique end as shown in FIGS. Using. The resin tube is made of polyurethane and has an outer diameter of 0.70 mm, an inner diameter of 0.45 mm, and a length of 200 before being swollen with an organic solvent.
A 0 mm tube was used.

The above resin tube was immersed in methyl ethyl ketone at room temperature for 1 minute or more to swell. This resin tube was placed on the outer periphery of the metal tube, and the extra length of the resin tube with respect to the length of the metal tube was arranged to protrude from the tip of the metal tube. In this state, the organic solvent was evaporated and dried at room temperature for 10 minutes or more, and the resin tube was shrunk and attached to the outer periphery of the metal tube.

Next, the part on which the resin tube was attached was immersed in a 5% by weight solution of 4,4-diphenylmethane isocyanate in methyl ethyl ketone for 30 to 120 seconds.
By leaving the reaction at 60 ° C. for 10 to 60 minutes,
Unreacted isocyanate groups were formed on the surface of the resin tube.

Furthermore, polyvinylpyrrolidone having a molecular weight of 1.2 million (trade name "K-90", manufactured by Wako Pure Chemical Industries, Ltd.) was added to 2
Immersed in a dichloromethane solution containing 10 to 10% by weight for 3 to 60 seconds and left at 60 ° C. for 3 to 12 hours to bind polyvinylpyrrolidone to unreacted isocyanate groups and to polymerize polyvinylpyrrolidone with each other to obtain hydrophilicity. A conductive resin film 40 was formed.

When the catheter thus obtained was used for angiography, it had moderate rigidity and was easy to push in.
Moreover, the tip was flexible and did not damage the blood vessel tissue, and excellent operability was obtained.

[0046]

As described above, according to the present invention,
The resin tube previously formed into a tubular shape was swollen with an organic solvent, the outer periphery of the metal tube was covered, and the organic solvent was evaporated and dried, so that the resin tube was adhered to the outer periphery of the metal tube. Even if the shape is complicated, it is possible to easily cover the resin layer with a uniform thickness.

Further, since the resin tube is integral and has no joint, even if a groove or the like is formed at the tip of the metal tube, or even if the metal tube is made of a mesh or the like, the medical tube has a smooth surface with no unevenness. Tubes can be easily manufactured. By adjusting the outer diameter of the metal tube and the inner diameter of the resin tube, a very thin resin coating is also possible.

Further, since the resin tube can be coated at room temperature, even if a super elastic material is used as the metal tube,
Its characteristics are not impaired.

[Brief description of the drawings]

FIG. 1 is a side view showing a metal tube in one embodiment of a medical tube according to the present invention.

FIG. 2 is a cross-sectional view showing a state where the metal tube is covered with a resin tube swollen with an organic solvent.

FIG. 3 is a cross-sectional view showing a state in which a solvent in the resin tube is evaporated and dried, and the resin tube is brought into close contact with the outer periphery of a metal tube.

FIG. 4 is a cross-sectional view showing a metal tube covered with a resin tube swollen with an organic solvent in another embodiment of the medical tube according to the present invention.

FIG. 5 is a cross-sectional view showing a state in which the solvent in the resin tube is evaporated and dried, and the resin tube is brought into close contact with the outer periphery of the metal tube.

FIG. 6 is a cross-sectional view showing a medical tube according to yet another embodiment of the present invention in a completed state.

[Explanation of symbols]

 11, 21, 31 Medical tube 12, 22, 32 Metal tube 13 Resin tube

Claims (3)

[Claims] 1. A medical tube, wherein a resin tube swollen with an organic solvent is covered on a metal tube, and the organic solvent is evaporated to dryness, whereby the resin tube is brought into close contact with the outer periphery of the metal tube. 2. The medical tube according to claim 1, wherein an inner diameter of the resin tube before being swollen with an organic solvent is equal to or smaller than an outer diameter of the metal tube. 3. The medical tube according to claim 1, wherein the resin tube protrudes from a tip of the metal tube.