JP2004305241A - Tube for sheathing core wire and manufacturing method therefor, and guide wire and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tube for sheathing a core wire and a manufacturing method therefor, and a guide wire and a manufacturing method therefor that can appropriately form a sheathing layer. <P>SOLUTION: The core wire 2 forming the guide wire 1 is sheathed with an inner layer 3a made of a synthetic resin containing a radiopaque material and can satisfy the need for the radiopacity the guide wire 1 is required to have. Since the inner layer 3a is sheathed with an outer layer 3a made of a synthetic resin whose content of the radiopaque material is lower than the content of the radiopaque material in the inner layer 3a, the area occupied by the radiopaque material in the outer surface of the outer layer 3a is smaller than a conventional one. Consequently, a sheathing layer 4 can be formed more appropriately than before. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a core coating tube, a method for manufacturing the same, a guide wire, and a method for manufacturing the same.
[0002]
2. Description of the Related Art Conventionally, a catheter has been inserted into a tubular trachea for examination and treatment of tubular organs of the human body such as blood vessels, ureters, bile ducts, and trachea. When inserting this catheter, a thin and flexible guide wire is inserted into the tubular organ in advance, the tip of the guide wire is allowed to reach the target site, and the catheter is inserted along the outer periphery of the guide wire. Like that.
[0003]
Since this guide wire is operated under X-ray fluoroscopy, X-ray opacity is required. Further, lubrication of the surface is required to prevent damage in the tubular organ and to improve operability. As a guide wire satisfying such requirements, for example, Japanese Patent Application Laid-Open No. 2001-327607 discloses a core wire, a synthetic resin covering body covering the core wire and containing an X-ray opaque material, and a covering body made of the synthetic resin. And a coating layer coated with a hydrophilic polymer material. According to this guide wire, the requirement for radiopacity is satisfied by the coating containing the radiopaque material, and the requirement for surface lubrication is satisfied by the coating layer.
[0004]
[Patent Document 1] Japanese Patent Application Laid-Open No. 2001-327607 (FIG. 1, 29th paragraph, etc.)
[0005]
However, since the coating layer is formed by bonding the hydrophilic polymer material of the coating layer and the synthetic resin of the coating, it contains the X-ray opaque material as described above. When the coating layer is formed on the coating, the area occupied by the synthetic resin on the outer surface of the coating is reduced by the X-ray opaque material, and there is a problem that the coating layer cannot be formed properly. Was.
[0006]
The present invention has been made in order to solve this problem, and an object of the present invention is to provide a core wire coating tube capable of appropriately forming a coating layer, a method of manufacturing the same, a guide wire, and a method of manufacturing the same. Things.
[0007]
In order to achieve this object, a core wire coating tube according to claim 1 is used as a guide wire for guiding a catheter to a target site, and a core wire constituting the guide wire is used. A first covering made of a synthetic resin containing an X-ray opaque material, covering the core wire, and covering the first covering, and X-rays in the first covering A second covering made of a synthetic resin containing an X-ray opaque material at a lower ratio than the content of the opaque material.
[0008]
According to the tube for covering a core wire according to the first aspect, the core wire constituting the guide wire is covered with the first synthetic resin-made sheath containing an X-ray opaque material, whereby X required for the guide wire is obtained. The requirement for line opacity is satisfied. Further, since the first coating is covered with the second coating made of a synthetic resin containing the X-ray opaque material at a lower ratio than the content of the X-ray opaque material in the first coating, the first coating is conventionally used. In comparison, the area occupied by the radiopaque material on the outer surface of the second coating is reduced.
[0009]
The core coating tube according to claim 2 is the core coating tube according to claim 1, wherein the content of the X-ray opaque material in the first coating is about 40% to about 70% by weight. The content of the X-ray opaque material in the second coating is about 40% by weight or less.
[0010]
According to a third aspect of the present invention, in the tube for covering a core wire according to the first or second aspect, the content of the X-ray opaque material in the second covering body is constituted by 0% by weight.
[0011]
According to a fourth aspect of the present invention, in the tube for covering a core wire according to any one of the first to third aspects, the second covering is thinner than the first covering.
[0012]
The core coating tube according to claim 5 is the core coating tube according to any one of claims 1 to 4, wherein the first coating and the second coating have an affinity for each other. It consists of.
[0013]
The tube for covering a core wire according to claim 6 is the tube for covering a core wire according to any one of claims 1 to 5, wherein the first coating and the second coating are made of polyurethane synthetic resin. It is configured.
[0014]
The method for manufacturing a core wire coating tube according to claim 7 is formed between a hollow cylindrical inner mold, a hollow cylindrical outer mold including the inner mold, and the inner mold and the outer mold. A manufacturing method for manufacturing the core wire coating tube according to any one of claims 1 to 6 using an extrusion molding apparatus having an annular flow path, wherein the first line is formed along an inner mold side in the annular flow path. Extruding a synthetic resin containing an X-ray opaque material as a constituent material of the coating, and extending the first coating as a constituent material of the second coating along the outer mold side in the annular flow path. An extrusion step of extruding a synthetic resin containing an X-ray opaque material at a lower ratio than the content rate of the X-ray opaque material, and simultaneously extruding and molding the first coating and the second coating; And a jetting step of jetting gas into the air passage of the inner die.
[0015]
According to the method for manufacturing a core wire coating tube according to the seventh aspect, the synthetic resin containing the X-ray opaque material, which is a constituent material of the first coating, is placed along the inner mold side in the annular flow path. Extruded. At the same time, the synthetic resin containing the X-ray opaque material at a lower ratio than the content of the X-ray opaque material in the first cover, which is a constituent material of the second cover, is formed along the outer mold side in the annular flow path. Extruded. Therefore, the first coating and the second coating are simultaneously extruded and formed. During this time, gas is being blown from the inner air passage toward the through passage of the first coating.
[0016]
An eighth aspect of the present invention provides a guide wire including the core covering tube according to any one of the first to sixth aspects, and a core covered by the first covering body of the core covering tube.
[0017]
The method for manufacturing a guide wire according to claim 9, wherein the hollow cylindrical inner die, the hollow cylindrical outer die including the inner die, and the annular flow formed between the inner die and the outer die. A method for manufacturing the guide wire according to claim 8, wherein the X-ray is a constituent material of the first coating body along an inner mold side in the annular flow path by using an extrusion molding apparatus having a path. While extruding a synthetic resin containing an opaque material, the content of the X-ray opaque material in the first coating, which is a constituent material of the second coating, along the outer mold side in the annular flow path An extrusion step of extruding a synthetic resin containing an X-ray opaque material at a lower rate and simultaneously extruding and molding the first coating and the second coating; And an insertion step of inserting into an airway.
[0018]
According to the method of manufacturing a guide wire according to the ninth aspect, the synthetic resin containing the X-ray opaque material, which is a constituent material of the first coating, is extruded along the inner mold side in the annular flow path. You. At the same time, the synthetic resin containing the X-ray opaque material at a lower ratio than the content of the X-ray opaque material in the first cover, which is a constituent material of the second cover, is formed along the outer mold side in the annular flow path. Extruded. Therefore, the first coating and the second coating are simultaneously extruded and formed. Also, at this time, the core wire is inserted into the through passage of the first covering from the inner die air passage.
[0019]
According to the tube for covering a core wire according to the first aspect, the core wire constituting the guide wire is covered with the first covering made of synthetic resin containing an X-ray opaque material. The requirement for radiopaque properties required for the wire can be satisfied. Also, the first coating is covered with a second synthetic resin coating that contains the X-ray opaque material at a lower rate than the content of the X-ray opaque material in the first coating. (2) The ratio of the area occupied by the radiopaque material on the outer surface of the coating is reduced as compared with the conventional case. That is, the ratio of the area occupied by the synthetic resin on the outer surface of the second coating increases as compared with the conventional case. Therefore, a coating layer can be formed more appropriately than in the conventional case.
[0020]
Further, even when the coating layer is not formed, the ratio of the area occupied by the X-ray opaque material on the outer surface of the second coating is smaller than that in the conventional case, so Roughness is suppressed. Therefore, there is an effect that damage to the inside of the tubular organ can be further suppressed and operability can be improved.
[0021]
According to the core wire coating tube according to claim 2 or 3, the content of the X-ray opaque material in the first coating is in the range of approximately 40% by weight to approximately 70% by weight, and the second coating. Since the content of the X-ray opaque material in the body is approximately 40% by weight or less, the effect of the core wire coating tube according to claim 1 can be further remarkably exhibited.
[0022]
According to the core wire coating tube of the fourth aspect, in addition to the effect of the core wire coating tube of any one of the first to third aspects, the second coating body is configured to be thinner than the first coating body. Therefore, there is an effect that it is possible to suppress an increase in the diameter of the core wire covering tube even when the second covering body is provided.
[0023]
According to the core coating tube of the fifth aspect, in addition to the effect of the core coating tube of any one of the first to fourth aspects, the first coating and the second coating are compatible with each other. And a synthetic resin having: Therefore, there is an effect that the weldability between the first coating and the second coating can be improved.
[0024]
According to the core coating tube according to the sixth aspect, in addition to the effect of the core coating tube according to any one of the first to fourth aspects, the first coating and the second coating are polyurethane-based. In addition, the effect of claim 5 can be more remarkably exhibited, and the polyurethane-based synthetic resin can be used with a hydrophilic polymer material or a biocompatible material constituting the coating layer. It is easy to be bonded, and the coating layer can be easily and appropriately formed.
[0025]
According to the method for manufacturing a core wire coating tube of the seventh aspect, the first coating and the second coating are simultaneously extruded and molded, so that the manufacturing process is performed even when the second coating is provided. There is an effect that the core wire covering tube can be manufactured without increasing. In the case where the first coating and the second coating are simultaneously extruded and formed, the synthetic resins of the respective layers are compatible with each other in the mold, so that there is an effect that stable and strong welding performance can be realized. .
[0026]
According to the guide wire of the eighth aspect, the core wire covering tube according to any one of the first to sixth aspects and the core wire covered by the first covering body of the core wire covering tube are provided. Thus, the effect according to any one of claims 1 to 6 can be obtained.
[0027]
According to the method for manufacturing a guide wire according to the ninth aspect, the first coating and the second coating are simultaneously extruded and formed, and at this time, the core wire extends from the inner air passage through the first coating. Is inserted. Therefore, there is an effect that the step of molding the core wire covering tube and the step of inserting and fitting the core wire into the through-hole of the first covering body can be performed in one step.
[0028]
Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. First, a configuration of a guidewire 1 according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a sectional view showing the guide wire 1. FIG. 2A is a perspective view showing a partial cross section of the guidewire 1, and FIG. 2B is a cross-sectional view of the guidewire 1 taken along a line II-II in FIG.
[0029]
The guide wire 1 is for guiding the catheter to the target site by inserting the distal end of the guide wire to the target site in the tubular organ before inserting the catheter. Its shape is formed in an elongated straight line whose diameter is reduced toward the tip. More specifically, the overall length L1 is approximately 5.0 m, the maximum diameter D1 is approximately 0.85 mm, and the diameter is approximately 300 mm from the tip (see L2 in FIG. 1). Have been. The total length L1, the maximum diameter portion D1, and the length L2 of the reduced diameter portion are appropriately set according to the type of the guide wire 1. For example, the total length L1 is reduced in a range of approximately 5.0 m to approximately 0.2 m. The length L2 of the diameter portion is set in a range of approximately 50 mm to 300 mm.
[0030]
The guide wire 1 mainly includes a core wire 2, a covering tube 3 covering the core wire 2, and a covering layer 4 covering the covering tube 3. The core wire 2 is for securing the rigidity of the guide wire 1. The core wire 2 is inserted into the through-hole of the coating tube 3 and includes a substantially linear base 2a and a diameter-reducing portion 2b tapering from the base 2a in a tapered shape. The base 2a and the reduced diameter portion 2b are integrally formed of a Ni—Ti alloy of a superelastic material. The Ni-Ti alloy is a shape memory alloy, is less likely to bend, and is suitable for operability inside a thin tube such as a tubular trachea.
[0031]
The base 2a is a portion formed with a substantially uniform diameter, and transmits the torque applied at hand to the reduced diameter portion 2b side along the axial direction. In order to efficiently transmit this torque to the reduced diameter portion 2b side, the outer diameter D2 is larger than the reduced diameter portion 2b and is approximately 0.50 mm.
[0032]
The reduced diameter portion 2b is a portion formed to be tapered from the base portion 2a, and has an outer diameter of about 0.1 mm at the foremost portion. By forming the reduced diameter portion 2b in this manner with respect to the base portion 2a formed with a substantially uniform diameter, the guide wire 1 can be easily inserted into the tubular organ, and the guide wire 1 can be continuously moved toward the foremost portion. Therefore, flexibility can be increased, and local bending can be prevented.
[0033]
The covering tube 3 is for covering the core wire 2 and corresponds to a tube for covering a core wire which is one of the present invention. The coating tube 3 is formed in a two-layer tube shape, and includes a through hole into which the core wire 2 is inserted, an inner layer 3a that forms the through hole, and an outer layer 3b that covers the inner layer 3a.
[0034]
The through hole is a hole into which the core wire 2 is inserted. The diameter is substantially uniform along the length direction and is smaller than the diameter D2 of the core wire 2. Therefore, the core wire 2 is inserted into the through hole so as to expand the through hole, and the core wire 2 inserted into the through hole is pressed against an inner layer 3a and an outer layer 3b described later. Thus, by forming the through-holes, the adhesion between the core wire 2 and the inner layer 3a can be improved. A polyurethane-based adhesive is applied to the tip end of the core wire 2 to fill a gap between the core wire 2 and the inner layer 3a.
[0035]
The inner layer 3a covers the core wire 2 and makes the guide wire 1 inserted into the tubular organ visible under fluoroscopy. The thickness D3 is substantially uniform, and is made of a synthetic resin containing an X-ray opaque material of about 70% by weight. Specifically, the thickness D3 is approximately 0.28 mm in a state where the core wire 2 is covered, polyurethane is used as a synthetic resin, and tungsten is used as an X-ray opaque material.
[0036]
The content of the radiopaque material contained in the inner layer 3a is not limited to approximately 70% by weight, but may be in the range of approximately 40% to approximately 70% by weight depending on the type of the guidewire 1. Is set by When the X-ray opaque material is contained in such a range, the guide wire 1 inserted into the tubular organ can be reliably visually recognized even under X-ray fluoroscopy.
[0037]
As the synthetic resin, in addition to polyurethane, polyethylene, polypropylene, polyolefin-based elastomer, polyester-based elastomer, polyamide-based elastomer, styrene-based elastomer, thermoplastic polyimide, polyvinyl chloride, and the like can be used. Further, as the X-ray opaque material, powder or a compound of barium sulfate, bismuth, gold, platinum or the like can be used in addition to tungsten.
[0038]
The outer layer 3b is a layer that covers the inner layer 3a, and the inner surface thereof is welded to the outer surface of the inner layer 3a. The thickness D4 is substantially uniform, and is made of a synthetic resin containing an X-ray opaque material of approximately 0% by weight. That is, the outer layer 3b does not contain an X-ray opaque material. Therefore, the X-ray opaque material is not exposed on the outer surface of the outer layer 3b, and the outer surface of the outer layer 3b is formed only of a synthetic resin.
[0039]
The thickness D4 of the outer layer 3b is approximately 0.07 mm when the core wire 2 is inserted into the through hole. That is, the outer layer 3b is configured to be thinner than the inner layer 3a. In order to make the guide wire 1 visible under X-ray fluoroscopy, the inner layer 3a needs to contain a predetermined amount of an X-ray opaque material, and the amount of the synthetic resin is regulated according to the content. The outer layer 3b only needs to be able to cover the inner layer 3a. Therefore, even when the outer layer 3b is formed, the increase in the diameter of the guide wire 1 is suppressed.
[0040]
As the synthetic resin constituting the outer layer 3b, it is preferable to select a material having an affinity for the synthetic resin constituting the inner layer 3a. Here, having affinity means synthetic resins having good adhesion to each other. As a combination of synthetic resins having affinity, for example, it is conceivable that the synthetic resin forming the inner layer 3a and the synthetic resin forming the outer layer 3b are made of the same resin or the same resin. In this embodiment, the synthetic resin of the outer layer 3b uses polyurethane, which is the same synthetic resin as the inner layer 3a.
[0041]
By thus forming both the inner layer 3a and the outer layer 3b of polyurethane, the weldability between the inner layer 3a and the outer layer 3b can be improved. In addition, since polyurethane is easily bonded to a later-described coating layer 4 with a hydrophilic polymer material or a biocompatible material as a constituent material, the coating layer 4 can be appropriately formed on the outer surface of the outer layer 3b.
[0042]
The outer layer 3b can be made of a synthetic resin such as polyethylene or polypropylene, in addition to the polyurethane, similarly to the inner layer 3a. Is preferred.
[0043]
When the core wire 2 is inserted into the through-hole of the covering tube 3 configured as described above, both ends of the covering tube 3 are opened. Therefore, caps 5 and 5 are welded to both ends of the coating tube 3. The caps 5, 5 are made of polyurethane and are formed in a substantially cylindrical shape, and are adhered to both ends of the covering tube 3 with a polyurethane-based adhesive. Thus, the core wire 2 can be hermetically sealed by the covering tube 3 and the caps 5 and 5. It is preferable that the outer surfaces of the caps 5 and 5 are formed in a hemispherical shape. By forming the outer surfaces of the caps 5 and 5 in a hemispherical shape, damage to the tubular organ can be suppressed.
[0044]
The coating layer 4 is for imparting lubrication and antithrombotic effects to the guidewire 1. This coating layer 4 is coated on the outer surface of the coating tube 3 (outer layer 3b) with a hydrophilic polymer material or a biocompatible material. Specifically, as the hydrophilic polymer material, a maleic anhydride copolymer, polyvinylpyrrolidone, polyacrylamide, or the like can be used. Further, as the biocompatible material, heparin, urokinase, hydroxyethyl methacrylate-styrene copolymer and the like can be used.
[0045]
As described above, since the outer layer 3b of the guidewire 1 does not contain an X-ray opaque material, the outer surface of the outer layer 3b is formed only of a synthetic resin. Therefore, as compared with the conventional case where the coating layer 4 is formed on the surface of a synthetic resin containing an X-ray opaque material that satisfies the X-ray opacity required for the guide wire, The hydrophilic polymer material or the like, which is a constituent material, is surely bonded to the synthetic resin of the outer layer 3b. Therefore, the coating layer 4 can be appropriately formed.
[0046]
Next, a method for manufacturing the above-described covered tube 3 and guide wire 1 will be described. FIG. 3A is a diagram for explaining a method for manufacturing the coated tube 3, and FIG. 3B is a diagram for explaining a method for manufacturing the guidewire 1. The coating tube 3 and the guide wire 1 are formed by an extrusion molding device. In this embodiment, only the die head 6 of the extrusion molding apparatus is illustrated, and other general screws, cylinders, screens, breaker plates, and the like provided in the extrusion molding apparatus are not illustrated.
[0047]
First, a method for manufacturing the coated tube 3 will be described with reference to FIG. As described above, the coating tube 3 is constituted by the inner layer 3a and the outer layer 3b. A powdery synthetic resin as a constituent material of the inner layer 3a and tungsten as an X-ray opaque material are kneaded and processed into a pellet shape. The pellets are sent to the die head 6 by the rotation of the screw, and are melted by heating or frictional heat from the cylinder during the rotation. Thereafter, pressure is applied by a screen, a breaker plate, or the like, and reaches the die head 6 in a molten state. On the other hand, the constituent material of the outer layer 3b also reaches the die head 6 like the constituent material of the inner layer 3a.
[0048]
Here, the die head 6 of the extrusion molding apparatus will be described. The die head 6 includes a hollow cylindrical inner die 7, a hollow cylindrical outer die 8 including the inner die 7, an annular flow path 9 formed between the inner die 7 and the outer die 8, On the upstream side of the annular flow path 9, there are provided partition walls 10, 10 for dividing the annular flow path 9 into an inner die 7 side and an outer die 8 side.
[0049]
The constituent material of the melted inner layer 3a flows along the inner mold 7 side in the annular flow path 9 and is extruded (see arrow A in the figure). On the other hand, the molten constituent material of the outer layer 3b flows along the outer mold 8 side in the annular flow path 9 and is extruded (see arrow B in the figure). Thus, the coated tube 3 having a two-layer structure having the inner layer 3a and the outer layer 3b is extruded.
[0050]
During this time, air is jetted from the air path of the inner mold 7 (see arrow C in the figure), a predetermined internal pressure is applied toward the through-hole of the coating tube 3, and the through-hole of the coating tube 3 is closed. Is prevented. However, it is also possible to form the coating tube 3 without blowing air from the air path of the inner mold 7, and the shape of the inner mold 7 is not limited to a hollow cylindrical shape, but is merely a columnar shape. Is also good.
[0051]
In addition, the core wire 2 previously processed mechanically or by etching is inserted into the formed coated tube 3, and when the core wire 2 is inserted, the caps 5, 5 are welded to both ends of the coated tube 3. You. Then, the outer surface of the coating tube 3 (the outer layer 3b) is coated with a hydrophilic polymer material or a biocompatible material to form a coating layer 4, and the guide wire 1 having the coating tube 3 is manufactured.
[0052]
Next, a method of manufacturing the guidewire 1 will be described with reference to FIG. The guide wire 1 is coated from the air passage formed in the inner die 7 of the die head 6 when the coating tube 3 having the two-layer structure having the inner layer 3a and the outer layer 3b is extruded by the same process as described above. The core wire 2 is inserted into a through passage formed in the tube 3 (see the arrow C in the figure). Therefore, the core wire 2 can be inserted and fitted at the same time when the covering tube 3 is formed.
[0053]
As described above, the present invention has been described based on the embodiments. However, the present invention is not limited to the above embodiments, and it is easily understood that various improvements and modifications can be made without departing from the spirit of the present invention. It can be inferred.
[0054]
For example, in the guidewire 1 of the present embodiment, the case where the coating layer 4 is formed on the entire circumference of the coating tube 3 has been described. However, the coating layer 4 does not necessarily need to be formed on the entire circumference of the coating tube 3, and the coating layer 4 may be formed on the distal end side.
[0055]
In the present embodiment, the case where the outer layer 3b contains the X-ray opaque material by 0% by weight has been described. However, the content of the X-ray opaque material in the outer layer 3b is not limited to 0% by weight. If the content is lower than the content of the X-ray opaque material in the inner layer 3a, the content is from 0% to approximately It can be set in the range of 40% by weight.
[0056]
As described above, even when the X-ray opaque material is contained in the outer layer 3b, the coating layer 4 can be appropriately formed as compared with the conventional case, and the outer layer 3b in a portion where the coating layer 4 is not formed is provided. Has the effect that tacking by the synthetic resin constituting the above can be suppressed.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a guide wire according to an embodiment of the present invention.
2A is a perspective view showing a partial cross section of the guide wire, and FIG. 2B is a cross-sectional view of the guide wire taken along a line II-II in FIG.
FIG. 3A is a diagram for explaining a method for manufacturing a coated tube, and FIG. 3B is a diagram for explaining a method for manufacturing a guide wire.
[Explanation of symbols]
1 Guide wire 2 Core wire 3 Coated tube (Tube for core wire coating)
3a Inner layer (first coating)
3b outer layer (second coating)
4 Coating layer 6 Die head (part of extrusion equipment)
7 Inner die 8 Outer die 9 Annular flow path

Claims (9)

Used for a guide wire for guiding a catheter to a target site, a core wire coating tube for coating a core wire constituting the guide wire,
A first covering body made of a synthetic resin that covers the core wire and contains an X-ray opaque material;
A second cover made of a synthetic resin that covers the first cover and contains the X-ray opaque material at a lower ratio than the content of the X-ray opaque material in the first cover. Characteristic tube for core wire coating. The content of the radiopaque material in the first coating is in a range of approximately 40% by weight to approximately 70% by weight,
2. The core wire coating tube according to claim 1, wherein the content of the radiopaque material in the second coating is configured to be approximately 40% by weight or less. 3. The core wire coating tube according to claim 1 or 2, wherein the content of the X-ray opaque material in the second coating is constituted by 0% by weight. The core wire coating tube according to any one of claims 1 to 3, wherein the second coating is configured to be thinner than the first coating. The core wire coating tube according to any one of claims 1 to 4, wherein the first coating and the second coating are made of synthetic resins having an affinity for each other. The core wire coating tube according to any one of claims 1 to 5, wherein the first coating and the second coating are made of a polyurethane synthetic resin. An extrusion molding apparatus having a hollow cylindrical inner mold, a hollow cylindrical outer mold containing the inner mold, and an annular flow path formed between the inner mold and the outer mold, according to claim 1, 6. A method for producing a core wire coating tube for producing the core wire coating tube according to any one of 6),
Along with the inner mold side in the annular flow path, the synthetic resin containing the X-ray opaque material that is a constituent material of the first coating body is extruded, and along the outer mold side in the annular flow path. Extruding a synthetic resin containing an X-ray opaque material at a lower rate than the content of the X-ray opaque material in the first coat, which is a constituent material of the second coat, and forming the first coat and the second coat An extrusion step of simultaneously extruding and molding the body,
And a jetting step of jetting gas into the air passage of the inner mold simultaneously with the extrusion step. A guide wire, comprising: the core wire covering tube according to any one of claims 1 to 6; and a core wire covered by a first covering body of the core wire covering tube. An extrusion molding apparatus having a hollow cylindrical inner mold, a hollow cylindrical outer mold enclosing the inner mold, and an annular flow path formed between the inner mold and the outer mold, according to claim 8, A method for manufacturing a guidewire for manufacturing the described guidewire,
Along with the inner mold side in the annular flow path, the synthetic resin containing the X-ray opaque material that is a constituent material of the first coating body is extruded, and along the outer mold side in the annular flow path. Extruding a synthetic resin containing an X-ray opaque material at a lower rate than the content of the X-ray opaque material in the first coat, which is a constituent material of the second coat, and forming the first coat and the second coat An extrusion step of simultaneously extruding and molding the body,
And a fitting step of fitting the core wire into the air passage of the inner mold simultaneously with the extrusion step.

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