JP2001149483A - Forming method of catheter tip end, and catheter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a forming method of a catheter tip end, by which the burden of a patient is less when the catheter is pierced and made to reside on the patient, wherein damages of a molding die or the like can be prevented from occurring at the time of the forming; and provide such a catheter. SOLUTION: A tapered hole section is formed in a die, and a catheter and a core rod are inserted in the die. Thus, a tapered section is formed on the catheter. At the same time, an excessive section of the catheter is cut off in this method for forming the catheter tip end into the tapered shape. Then, this catheter is obtained by such a method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a distal end of an indwelling catheter used for indwelling an artery and a vein, for example, for infusion.
The present invention relates to an indwelling catheter and an indwelling needle assembly.

[0002]

2. Description of the Related Art When performing infusion or the like on a patient, an indwelling needle assembly including an indwelling catheter (outer needle) and an inner needle is used. This indwelling needle assembly has a double needle structure in which the inner needle is inserted into the indwelling catheter and is integrated, and only the inner needle is withdrawn after arteriovenous puncture, leaving only the indwelling catheter in the living body. Is what you do. Therefore, it is preferable that the indwelling catheter is inserted into a blood vessel in a manner following the inner needle. For this purpose, the distal end of the indwelling catheter is required to have a shape with a smaller step than the inner needle.

In the prior art, a method of inserting a catheter into a mold and using a core rod inserted into the catheter has been adopted to form such a tip having a small step. In this method, the mold is heated, and the burr of the catheter generated by the heat melting is cut by bringing the mold into contact with the peripheral edge of the tip of the core rod to form the tip.

However, in the conventional method of forming the distal end of the catheter, the core rod is applied to a part of the tapered hole of the inner hole of the mold to cut off an excessive distal end, so that there are the following problems. It is not possible to process a catheter utilizing all the tapered holes provided in the mold. That is, only a catheter having a tapered portion shorter than the tapered hole provided in the mold can be obtained. In order to lengthen the tapered portion by the conventional forming method, it is necessary to reduce the diameter of the core rod, but the durability is inferior due to the load at the time of processing. A long gentle slope cannot be set inside the tapered portion of the catheter tip, and the tip is not supple. Since the peripheral edge of the core rod directly hits the mold, there is a problem that the core rod and the mold are easily damaged.

[0005]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, the present invention provides a catheter having a long tapered portion, and the tapered end of the catheter which can set the tapered portion inside the catheter tip to a long gentle slope. It is an object of the present invention to provide a method of forming a shape and a catheter obtained by the method. As a result, it is possible to obtain a catheter capable of accepting the outer diameter of the inner needle within a certain wide range, to select the outer diameter of the inner needle according to the purpose, and to reduce the burden on the patient particularly when a thin inner needle is used. be able to. Another object of the present invention is to provide a method for forming a tapered tip of a catheter that is less likely to cause damage to a core rod and a mold.

[0006]

The above object is achieved by the present invention described below. (1) The present invention relates to a mold having an inner hole in which a large-diameter hole portion and a small-diameter hole portion communicate with each other via a tapered hole portion. The catheter is inserted by inserting the catheter from the large-diameter hole portion to the small-diameter hole portion to form a tapered portion in the catheter, and by inserting the core rod into the small-diameter hole portion from within the catheter. Cutting the portion inserted in the small-diameter hole portion into a tapered tip of the catheter.

(2) In the present invention, the end of the core rod to be inserted into the inner hole of the mold has a tapered shape, and the tapered shape has a small diameter portion larger than the inner diameter of the small diameter hole portion of the mold. The small-diameter portion, the large-diameter portion of which is larger than the inner diameter of the small-diameter hole portion of the mold, wherein the core rod inserts the tapered small-diameter portion into the small-diameter hole portion of the mold. This is a method of forming the tip of the catheter according to (1) into a tapered shape.

(3) The present invention is characterized in that the catheter is softened to form a tapered portion by heating at least the vicinity of the tapered hole portion of the inner hole of the mold. ) To (2), wherein the catheter tip is formed in a tapered shape.

(4) The present invention is a catheter obtained by the method described in (1) or (2), wherein the catheter tip is formed in a tapered shape. (5) The present invention is an indwelling needle assembly in which an inner needle having an outer diameter equal to or larger than an inner diameter of an opening at a tapered end of the catheter is inserted into the catheter according to (4).

(6) The present invention relates to a catheter having a tapered distal end, wherein the distal end of the tapered portion has no end face, and the cross-sectional shape of the tapered portion in the axial direction is proportionally cut from the distal end. The tapered portion has an increased thickness, and the ratio of the axial length of the tapered portion to the axial length of the tapered portion is 0.1.
~ 1, more preferably 0.35-0.85. (7) The present invention is an indwelling needle assembly in which an inner needle having an outer diameter equal to or larger than the inner diameter of the opening at the distal end of the catheter is inserted into the catheter according to (6).

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for forming a tapered tip of a catheter of the present invention and a catheter obtained by the method will be described below with reference to the accompanying drawings. FIG. 1 schematically shows a cross section of a mold 1 and a core rod 2 according to the present invention, and FIG.
The tapered portion 31 is formed in the catheter 3 with the core rod 2 and the extra portion 32 is cut from the catheter 3 to schematically show a cross section.

The mold 1 has a mold body 15 having an inner hole 11 in which a large diameter hole 12 and a small diameter hole 14 communicate with each other via a tapered hole 13. The large-diameter hole portion 12 is for inserting the core rod 2 and the catheter 3 from the opening thereof,
The tapered hole portion 13 forms the tapered portion 31 of the catheter 3, and the small diameter hole portion 14 cuts and discharges an extra portion 32 from the tapered portion 31 of the catheter 3.

As a material constituting the mold 1, specifically, a material made of a metal such as nickel and harder than the core rod 2 is suitable. The mold 1 is desirably a material that heats and softens the catheter 3 to form the tapered portion 31. Other methods include reducing the diameter by pressure.

The axial length A of the tapered hole 13 of the mold 1 is preferably 0.05 to 0.50 mm, more preferably 0.08 to 0.30 mm. The inner diameter of the large-diameter hole 12 is preferably 0.35 to 2.00 mm in diameter, more preferably 0.40 to 1.90 mm. The inner diameter of the small diameter hole portion 14 is preferably 0.20 to 1.70 mm in diameter, more preferably 0.25 to 1.50 mm. The axial length of the large-diameter hole 12 and the small-diameter hole 14 is not particularly limited.
It can be arbitrarily selected depending on the length of the catheter 3 and the like.

The core rod 2 preferably has a tapered portion 21 at the tip. Tapered portion 2 of core rod 2
1 has a relationship of 1 ° <(θ−θ ′) <50 °, and more preferably 5 ° <(θ, with respect to the angle θ of the tapered hole of the mold 1. −θ ′) <20
°. Specifically, the angle θ ′ is preferably from 8 ° to 22 °, and more preferably from 10 ° to 20 °. In addition, core rod 2
More specifically, is preferably made of a metal such as copper, which is softer than the mold 1. Further, the surface of the tapered portion 21 of the core rod 2 preferably has a surface roughness of about 0.8 μm.

The axial length B of the tapered shape of the core rod 2 is preferably 0.05 to 2.0 mm, and more preferably 0.4 to 0.9 mm. The diameter of the tapered portion of the core rod 2 can be arbitrarily selected depending on the size of the catheter 3, but is preferably 0.05 to 1.60 mm at the thin tip, more preferably 0.10 to 1.50 mm, and the tapered shape. It is preferably 0.25 to 1.90 mm at the root portion, more preferably 0.30 to 1.70 mm.

An example in which the taper portion 31 is formed on the catheter 3 by the mold 1 and the core rod 2 will be described below. The core rod 2 is inserted into the catheter 3 in advance. At this time, it is desirable that the distal end position of the core rod 2 in the tapered direction from the distal end position of the catheter 3 protrudes from −0.03 to +2.0 mm, and more preferably −0.2 to +0.5 mm.

The catheter 3 into which the core rod 2 has been inserted is
A load is applied so as to be pushed from the large diameter hole 12 to the vicinity of the tapered hole 13. This position can be arbitrarily selected depending on the thickness and thickness of the catheter 3 and the shape of the tapered hole 13 to be formed. At least the tapered hole 13 of the mold 1 is heated. The temperature at this time varies depending on the material of the catheter 3 and the like, but is about 160 to 22.
0 ° C.

The mold 1 is heated. Thereby, the catheter 3 into which the core rod 2 is inserted is further pushed in by the load,
Thereby, the taper portion 31 having the same shape as the tapered hole portion 13 is formed in the catheter 3 softened by heating, and the tapered portion 21 of the core rod 2 is pushed into the small diameter hole portion 14 of the mold 1. And the tapered portion 21
The tapered surface of the catheter 3 and the edge 141 of the small-diameter hole portion 14 come into contact with each other, and the extra portion 32 ahead of the tapered portion 31 of the catheter 3
Is disconnected. The catheter 3 into which the core rod 2 has been inserted is
The excess part 32 is removed from the small-diameter hole part 14 by the mold 1.
It is discharged outside.

FIG. 3 shows a cross section of an example of the tapered portion 31 of the catheter 3 formed by the above-described method. The tapered portion 31 has no end face at the front end, and the cross-sectional shape in the axial direction has a thickness change portion 3 in which the cross-sectional area increases proportionally from the front end.
3 The ratio of the axial length D of the thickness changing portion 33 to the axial length C of the tapered portion 31 is 0.15 to
To 1, more preferably 0.35 to 0.85. In addition,
FIG. 4 shows a cross section of an example in which an end face 33 is provided at the tip of the tapered portion.

In this embodiment, the material of the catheter 3 is not particularly limited, but examples thereof include polyurethane, polytetrafluoroethylene, and ethylene-tetrafluoroethylene copolymer. Outer diameter is 0.50-2.50m in diameter
m is more preferably 0.60 to 2.30 mm, and the inner diameter is preferably 0.30 to 2.00 mm in diameter.
More preferably, it is 0.40 to 1.85 mm. The wall thickness is preferably 0.05 to 0.25 mm, more preferably 0.2 to 0.25 mm.
08 to 0.21 mm.

The catheter 3 obtained according to the present embodiment
Can be used mainly as an indwelling needle assembly by inserting an inner needle having an outer diameter greater than the inner diameter of the opening at the end in the tapered direction.

[0023]

According to the method for forming the tip of a catheter of the present invention, a catheter can be machined utilizing all the tapered holes provided in the mold. That is, a catheter having a long tapered portion can be obtained, and such a catheter has a small piercing resistance due to the long tapered portion and can reduce the burden on the patient. According to the method for forming a catheter tip of the present invention, a catheter having no end face at the tip can be obtained, and such a catheter has low piercing resistance and can reduce the burden on the patient.

According to the method of forming a catheter tip of the present invention, a catheter having a long gentle slope portion, that is, a wall thickness change portion having a proportionally larger cross-sectional area inside the tapered portion of the catheter tip can be obtained. When used as an indwelling needle assembly due to the thickness change part,
The outer diameter of the inner needle can be tolerated within a certain wide range, that is, the outer diameter of the inner needle can be selected according to the purpose, reducing the burden on the patient, especially when a narrow inner needle is used. can do. Further, when used as an indwelling needle assembly, the thickness change portion can reduce the withdrawal resistance when the inner needle is withdrawn from the catheter.

According to the method for forming a catheter tip of the present invention, even when a catheter having a long tapered portion is to be obtained, it is not necessary to reduce the diameter of the core rod as a whole, and the durability of the core rod is improved. According to the method for forming the tip of the catheter of the present invention, the peripheral edge of the tip of the mandrel does not directly hit the mold, so that the mandrel and the mold can be prevented from being damaged.
Further, since the method of forming the tip of the catheter of the present invention is a method of inserting the tip of the core rod into the small-diameter hole of the mold, it is possible to obtain catheters having various tip shapes depending on the combination of the core rod and the mold. .

[Brief description of the drawings]

FIG. 1 schematically shows a cross section of a mold 1 and a core rod 2 according to the present invention.

FIG. 2 schematically illustrates a cross section of an example of an embodiment of the present invention.

FIG. 3 shows a cross section of a tapered portion of the catheter of the present invention.

FIG. 4 shows a cross section of a catheter having an end face at the tip.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 type | mold 11 inner hole 12 large diameter hole 13 taper-shaped hole 14 small diameter hole 15 type main body 2 core rod 21 taper-shaped part 3 catheter 31 taper part 32 extra part 33 thickness change part

Claims (7)

[Claims] 1. A catheter and a core rod are inserted through the large-diameter hole side opening of the inner hole of a type having an inner hole in which a large-diameter hole portion and a small-diameter hole portion communicate with each other via a tapered hole portion. The taper portion is formed in the catheter by inserting the catheter from the large-diameter hole portion to the small-diameter hole portion, and the core rod is inserted into the small-diameter hole portion from within the catheter to thereby form the catheter. A method for forming a tip of a catheter in a tapered shape, comprising cutting a portion inserted into a small-diameter hole. 2. The core rod has a tapered end inserted into the inner hole of the mold, and the tapered shape has a small-diameter portion smaller than an inner diameter of the small-diameter hole portion of the mold and a large-diameter portion. The part according to claim 1, wherein the part is larger than the inner diameter of the small diameter hole of the mold, and the core rod inserts the tapered small diameter part into the small diameter hole of the mold. A method of forming the tip of a catheter into a tapered shape. 3. The taper according to claim 1, wherein the catheter is softened to form a tapered portion by heating at least the vicinity of the tapered hole portion of the inner hole of the mold. A method of forming the tip of a catheter into a tapered shape. 4. A catheter obtained by the method according to claim 1, wherein the catheter tip is formed in a tapered shape. 5. An indwelling needle assembly, wherein an inner needle having an outer diameter equal to or larger than the inner diameter of an opening at a tapered end of the catheter is inserted into the catheter according to claim 4. 6. A catheter having a tapered distal end, wherein the distal end of the tapered portion has no end face, and the tapered portion has a cross-sectional shape in the axial direction whose cross-sectional area increases proportionally from the distal end. A catheter having a thickness change portion, wherein a ratio of an axial length of the thickness change portion to an axial length of the taper portion is 0.15 to 1. 7. An indwelling needle assembly comprising the catheter according to claim 6, wherein an inner needle having an outer diameter equal to or larger than the inner diameter of the opening at the distal end of the catheter is inserted.