JP3232553B2 - Catheter and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for manufacturing a catheter. More specifically, the present invention relates to
The present invention relates to an improvement of the invention proposed in Japanese Patent No. 270063.

[0002]

2. Description of the Related Art Conventionally, in the case of blood transfusion or infusion,
A catheter (referred to as an indwelling needle) temporarily indwelled in a blood vessel is often used. The indwelling needle generally consists of an outer needle made of thermoplastic resin and an inner needle made of stainless steel, and after inserting into the body with the inner needle attached to the outer needle, the inner needle is removed and a blood transfusion set is inserted into the remaining outer needle. And an infusion set are used. The distal end of the indwelling needle is formed so as to be thin in order to reduce the resistance at the time of insertion into the body, and is formed so as to make the step with the inner needle as small as possible. Conventionally, polytetrafluoroethylene (PTFE), polyurethane, polyethylene, or the like has been used as a material for forming the outer needle, and a method of processing the tip, such as injection molding or grinding, is employed. Have been.

[0003]

However, when manufacturing the outer needle of the indwelling needle made of synthetic resin, the conventional tip processing method has the following problems. That is, the method of injection molding the whole is long molding time, it is difficult to manufacture a thin indwelling needle, the tip is easily damaged and it is difficult to automatically align, so it takes time to process after molding, and the mold is expensive. is there,
If the thickness of the inner needle varies, the fitting strength of the inner needle and the outer needle varies, and material loss occurs and uneconomical except when using a hot runner mold. ing. In addition, the method of grinding the tip has a drawback that dust adheres to the tube surface because static electricity is generated by grinding. As a solution to such a drawback, the present applicant inserts a metal core into a tube, heats and softens the tip of the tube into which the metal core is inserted, and pushes the metal core into a mold and a metal core. A method of processing the tip of a tube has already been proposed (Japanese Patent Laid-Open No. 63-270).
No. 063).

However, the above-mentioned Japanese Patent Application Laid-Open No. 63-2700
The method disclosed in JP-A-63-63, in the case of manufacturing a thin catheter or a long catheter, may not maintain rigidity of a core metal inserted into a catheter having no distal end portion, and may result in poor processing. In some cases, a perfect circle was not formed, or a shape defect at the tip such as a crack at the tip occurred. The present invention has been made in view of the above circumstances.
An object of the present invention is to provide a method for manufacturing a catheter in which the drawbacks of the invention of Japanese Patent No. 270063 are improved.

[0005]

SUMMARY OF THE INVENTION According to the present invention, in order to solve the above-mentioned problems, it is possible to eliminate processing defects caused by the length and thinness of a catheter by pulling a core from under a mold. And arrived at the present invention. That is, the present invention provides (a) a catheter having a distal end portion formed of a needle base and a tube, wherein the outer needle tube has a base having an outer diameter smaller than the inner diameter of the tube and a distal end of the base. Is inserted until the tip of the base of the core comes to a position retracted from the tip of the tube by a predetermined length.
(B) While holding the core so that it does not move inside the tube, the tube into which the core is inserted in step (a) has a hole diameter larger than the outer diameter of the base of the core and smaller than the outer diameter of the tube. Insert the tube into a preheated mold until the tube is supported. (C) After the tube is heated and softened for a predetermined time, the tip of the core is pulled from below the mold while holding the needle base of the outer needle so that the tip of the base of the core is at a predetermined position in the mold. And hold for a certain period of time.
(D) The mold after the step (c) is cooled for a predetermined time. (E) Pull out the tube into which the core has been inserted from the mold after the step (d). (F) Pull out the metal core from the tube. (G) Cut the tip of the tube at a predetermined position. The method for producing a catheter comprises the steps of: Further, a catheter manufactured by this method and having a wall thickness of 0.05 mm or less at the distal end of the tube.

Here, the mold employed in the manufacturing method of the present invention is such that the cavity of the mold has a relatively large taper following the tube insertion opening having a diameter sufficiently larger than the outer diameter of the tube. A first tapered portion having a hole diameter larger than the outer diameter, a second tapered portion reduced in diameter with a gentle taper following the first tapered portion, and a tube formed in the same diameter cylindrical shape following the second tapered portion. It is preferable to include a straight portion having a hole diameter smaller than the outer diameter and larger than the outer diameter of the base of the cored bar. In addition, the core metal includes a pipe having an outer diameter smaller than the inner diameter of the tube, and a core wire inserted into a lumen of the pipe, and the core wire is sufficiently longer than the pipe, and the inner end of the pipe is provided at the base end. A member having a flange having an outer diameter larger than the cavity may be employed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory view of the catheter of the present invention, FIGS. 2 to 5 are explanatory views of the manufacturing method of the present invention, and FIG.
FIG. 4 is a view showing another embodiment of the core used in the manufacturing method of the present invention. In the catheter 1 of the present invention, the thickness of the distal end portion 13 of the tube 11 is formed to be 0.05 mm or less by the manufacturing method of the present invention. As shown in FIG. 1, a synthetic resin such as a polyurethane resin or polyvinyl chloride is formed. Hub 1 formed of plastic such as polypropylene, polyethylene, or polycarbonate at one end of tube 11 formed of resin.
2 is attached.

The formation of the distal end of the catheter 1 of the present invention is achieved by the manufacturing method of the present invention. According to this method, the molding conditions such as the cavity shape of the mold, the outer diameter of the core metal, the heating temperature, the heating time, the cooling temperature, and the cooling time can be made constant, so that a constantly constant tip shape can be obtained. Can be. Hereinafter, the manufacturing method of the present invention will be described with reference to FIGS. First, (a) a synthetic resin catheter having an unformed distal end portion as shown in FIG.
First, a core 2 having a base 21 having an outer diameter smaller than the inner diameter of the tube 11 and a tip 22 having a smaller outer diameter extended from the tip of the base 21 is attached to the base 21 of the core 21. Insert until the tip comes to the position retracted a predetermined length from the tip of the tube. Here, tube 1 of cored bar 2
Although the insertion into 1 is automatically performed using a special machine (not shown), generally, except for special cases,
The distal end is inserted to a position withdrawn from the distal end of the tube 11 by 4 to 6 mm, preferably about 5 mm. As shown in FIG. 2, the mold 3 has a cavity including a first tapered portion 31, a second tapered portion 32, and a straight portion 33, and the first tapered portion 31 has a hole diameter outside the tube 11. In particular, the tube insertion port 34 is formed so that the tube 11 can be easily inserted.
It is formed with a sufficiently larger diameter. Although the taper of the first taper portion 31 is not particularly limited,
Generally, it is formed at about 30 ° to 60 °.

The second tapered portion 32 is a portion that determines the distal end shape of the catheter 1. The second tapered portion 32 is reduced in diameter with a gentle taper continuously from the first tapered portion 31, and is connected to the straight portion 33. The hole diameter of the second tapered portion 32 is the first tapered portion 3
At the point of contact with No. 1, the diameter is larger than the outer diameter of the tube 11, and at the point of contact with the straight portion 33, the diameter is smaller than the outer diameter of the tube 11, and the taper is preferably 4 ° to 15 °.
Is formed. When the taper is 15 ° or more, the puncture resistance of the formed catheter becomes large, and when this is pierced into a vein of a patient as an outer needle of an indwelling needle, for example, it may cause pain to the patient. When the taper is smaller than 4 °, the taper is too long, and therefore the distal end portion 13 of the catheter 1 is long, so that the wall thickness is naturally too small. When the catheter 1 is pierced, it is not preferable because the catheter 1 may be turned up at the time of piercing. The hole diameter of the straight portion 33 is smaller than the outer diameter of the tube 11 and larger than the outer diameter of the base 21 of the cored bar 2, and the length of the straight portion 33 is determined by the size of the indwelling needle 1.

Next, in step (A), the tube 11 into which the metal core 2 has been inserted is inserted into the tube 11 in step (A), for example, so that the core metal 2 does not move inside the tube 11.
Are fixed on the same axis, and inserted into the mold 3 heated to a predetermined temperature in advance until the tube 11 is supported (see FIG. 3). Next, in the step (c), after the tube 11 is heated and softened for 0.5 to 1.0 second, FIG.
As shown in the figure, while holding the needle base 12 of the catheter 1, the distal end portion 22 of the core 2 protruding downward from the mold 3 is grasped and pulled downward, and the core 2 is moved to a predetermined position of the mold 3. Push it in further. After maintaining in this state for 5 to 10 seconds, in the step (d), the mold 4 after the step (c) is cooled by air blow, and then in the step (e),
The tube 11 into which the core 2 has been inserted is pulled out from the mold 3 after the step (d) (see FIG. 5). In the step (f), the core 2 is pulled out from the tube 11, and finally the step (key) is completed. In), the distal end portion 13 of the tube 11 may be cut at a predetermined position.

Incidentally, as the core 2, one shown in FIG. 6 can also be employed. This is composed of a pipe 23 having an outer diameter smaller than the inner diameter of the tube 11, and a core wire 24 inserted into the lumen of the pipe 23. The core wire 24 is sufficiently longer than the pipe 23 and has a The flange 25 has an outer diameter larger than the inner diameter of the pipe 23. Core wire 24
Is pulled downward in the mold 3, the flange 2 of the core wire 24
5 collides with the pipe 23 and pushes it down, so that the tip processing becomes possible.

[0012]

As is apparent from the above description, by employing the present invention, it is possible to provide a catheter having a stable tip shape and a small piercing resistance even in a long catheter or a thin catheter. It can reduce the physical distress of the patient.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a catheter of the present invention.

FIG. 2 is an explanatory diagram of a manufacturing method of the present invention.

FIG. 3 is an explanatory view of the manufacturing method of the present invention.

FIG. 4 is an explanatory view of a manufacturing method of the present invention.

FIG. 5 is an explanatory view of the manufacturing method of the present invention.

FIG. 6 is an explanatory view showing another embodiment of the core used in the present invention.

[Explanation of symbols]

 Reference Signs List 1 catheter 11 tube 12 hub 13 distal end 2 core metal 21 base 22 distal end 23 pipe 24 core wire 25 flange 3 mold 31 first taper portion 32 second taper portion 33 straight portion

Claims (4)

(57) [Claims] 1. A method for producing a catheter comprising the following steps. (A) Prepare a catheter having a distal end formed of a needle base and a tube, and provide, in the tube of the catheter, a base having an outer diameter smaller than the inner diameter of the tube, and a further smaller part extended to the distal end of the base. A core bar having an outer diameter is inserted until the tip of the base of the core bar is retracted from the distal end of the tube by a predetermined length. (B) While holding the core so that it does not move inside the tube, the tube into which the core is inserted in step (a) has a hole diameter larger than the outer diameter of the base of the core and smaller than the outer diameter of the tube. Insert the tube into a preheated mold until the tube is supported. (C) After the tube is heated and softened for a predetermined time, the tip of the core is pulled from below the mold while holding the needle base of the outer needle so that the tip of the base of the core is at a predetermined position in the mold. And hold for a certain period of time. (D) The mold after the step (c) is cooled for a predetermined time. (E) Pull out the tube into which the core has been inserted from the mold after the step (d). (F) Pull out the metal core from the tube. (G) Cut the tip of the tube at a predetermined position. 2. A first tapered portion having a hole diameter larger than the outer diameter of the tube, wherein the cavity of the mold has a tube insertion port having a diameter sufficiently larger than the outer diameter of the tube, and a hole having a larger diameter than the outer diameter of the tube. A second taper portion that is reduced in diameter with a gradual taper following the first taper portion, and is smaller than the outer diameter of the tube formed in a cylindrical shape having the same diameter following the second taper portion;
2. The method according to claim 1, further comprising a straight portion having a hole diameter larger than the outer diameter of the base of the cored bar. 3. A core bar comprising a pipe having an outer diameter smaller than the inner diameter of a tube, and a core wire inserted into a lumen of the pipe, wherein the core wire is sufficiently longer than the pipe, and a pipe is provided at a base end thereof. The manufacturing method according to claim 1, further comprising a flange having an outer diameter larger than the inner diameter of the inner cavity. 4. The catheter according to claim 1, wherein the thickness of the distal end portion of the tube is formed to be 0.05 mm or less.