JPH09313612A - Catheter and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catheter which is formed by using a synthetic resin tube and is low in pricking resistance and its production. SOLUTION: An arbor 2 consisting of a base part 21 and a front end 22 extended at the front end of the base part 21 is inserted into the tube 11 of the catheter not formed with the front end until the arbor comes to a position where the front end of the base part 21 retracts by a prescribed length from the front end of the tube. Next, the tube 11 inserted with the arbor 2 is inserted into a metal mold 3 heated to a prescribed temp. until the state of supporting the tube is attained while the arbor 2 is held. The tube 11 is then softened by heating for a prescribed time and therefore, the front end 22 is pulled to push the arbor 2 into the metal mold 3. The arbor is held for a specified time and the metal mold 3 is cooled for a specified time. The tube 11 inserted with the arbor 2 is drawn out of the metal mold 3 and the arbor 2 is drawn from the tube 11. The front end 13 of the tube 11 is then cut at a prescribed position.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for manufacturing a catheter. More specifically, the present invention is disclosed in JP-A-63-
It relates to an improvement of the invention proposed in Japanese Patent No. 270063.

[0002]

2. Description of the Related Art Conventionally, when transfusing blood or infusion,
A catheter (indwelling needle) that is temporarily placed 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.After inserting the inner needle on the outer needle and inserting it into the body, the inner needle is removed and the remaining outer needle is transfused. Or infusion set is used. The tip of the indwelling needle outer needle is formed thin so as to reduce the resistance when it is inserted into the body, and is made so that the step with the inner needle is made as small as possible. Polytetrafluoroethylene (PTFE), polyurethane, polyethylene, etc. have been conventionally used as the material for forming the outer needle, and the method for processing the tip includes the method of injection molding or the method of grinding the whole. Has been done.

[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 outer needle, the tip is easily scratched, and it is difficult to automatically align the alignment, so it takes time to process after molding, and the mold is expensive. is there,
It has drawbacks such as variation in fitting strength between inner and outer needles when there is variation in the thickness of the inner needle, and uneconomical material loss unless a hot runner die is used. ing. Further, the method of grinding the tip portion has a drawback that dust is attached to the tube surface because static electricity is generated by the grinding. As a solution to such a drawback, the applicant of the present invention inserts a cored bar into a tube, heats and softens the tip of the tube into which the cored bar is inserted, and presses the cored bar into a mold and a cored bar. A method of processing the tip of the tube between the two has been proposed (Japanese Patent Laid-Open No. 63-270).
063).

However, the above-mentioned Japanese Patent Laid-Open No. 63-2700.
In the method disclosed in Japanese Patent Laid-Open No. 63, when a thin catheter or a long catheter is manufactured, the rigidity of a cored bar to be inserted into a catheter having a tip-unformed part may not be maintained, resulting in defective processing, or even if processing is possible. In some cases, the shape of the tip was not perfect, or the tip had a defective shape such as a crack at the tip. The present invention has been made in view of the above circumstances, and is disclosed in JP-A-63-
It is an object of the present invention to provide a method for manufacturing a catheter, in which the drawbacks of the invention of Japanese Patent No. 270063 are improved.

[0005]

In order to solve the above-mentioned problems, the present invention is capable of eliminating processing defects due to the length and thinness of the catheter by pulling the cored bar from under the mold. And has reached the present invention. That is, the present invention provides (a) a catheter having a needle base and a tube whose tip is not formed, and a tube of the outer needle having a base having an outer diameter smaller than the inner diameter of the tube and a tip of the base. A cored bar having a tip portion having a smaller outer diameter extended to the end is inserted until the tip of the base of the cored bar is at a position retracted by a predetermined length from the tip of the tube.
(A) The tube in 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 while holding the core so as not to move inside the tube. Insert into a preheated mold until the tube is in support. (C) After heating the tube for a certain period of time to soften it, pull the tip of the cored bar from below the mold while holding the needle base of the outer needle so that the tip of the base of the cored bar is at the specified position of the mold. Hold it for a certain period of time.
(D) Cool the mold for which the step (C) has been completed for a certain period of time. (E) Pull out the tube with the cored bar inserted from the mold that completed step (d). (F) Pull out the core metal from the tube. (G) Cut the tip of the tube at a predetermined position. A method for manufacturing a catheter, which comprises the steps of Further, the catheter manufactured by this method has a wall thickness of 0.05 mm or less at the distal end portion of the tube.

Here, in the mold employed in the manufacturing method of the present invention, the cavity of the mold has a tube insertion opening having a diameter sufficiently larger than the outer diameter of the tube, followed by a tube having a relatively large taper. A first taper portion having a hole diameter larger than the outer diameter, a second taper portion that follows the first taper portion and reduces in diameter with a gradual taper, and a tube formed in the same diameter tube following the second taper 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 portion of the core metal. The core metal includes a pipe having an outer diameter smaller than the inner diameter of the tube, and a core wire inserted into the inner cavity of the pipe, the core wire being sufficiently longer than the pipe, and the inner end of the pipe being inside the pipe. You may employ | adopt the thing which has the collar whose outer diameter is larger than a cavity.

[0007]

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

The formation of the distal end portion 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 consistent tip shape can always be obtained. You can Hereinafter, the manufacturing method of the present invention will be described with reference to FIGS. First, (a) prepare a catheter made of a synthetic resin and having no tip portion formed as shown in FIG.
1, a core metal 2 having a base portion 21 having an outer diameter smaller than the inner diameter of the tube 11 and a tip portion 22 having an even smaller outer diameter extended at the tip of the base portion 21 is attached to the base metal 21 of the core metal 2. Insert until the tip comes to a position retracted from the tip of the tube for a specified length. Here, tube 1 of core metal 2
The insertion into 1 is automatically performed using a dedicated machine not shown, but generally except for special cases, the core metal 2 is
The tip is inserted to a position where it is retracted from the tip of the tube 11 by 4 to 6 mm, preferably about 5 mm. As shown in FIG. 2, the mold 3 has a cavity composed of a first taper portion 31, a second taper portion 32, and a straight portion 33, and the first taper portion 31 has a hole diameter outside the tube 11. The tube insertion opening 34 is formed to have a diameter larger than that of the tube 11 so that the tube 11 can be easily inserted.
It has a sufficiently larger diameter. The taper of the first taper portion 31 is not particularly limited,
It is generally formed at about 30 ° to 60 °.

The second taper portion 32 is a portion that determines the shape of the tip of the catheter 1. The second taper portion 32 is continuous with the first taper portion 31 in diameter with a gentle taper and is continuous with the straight portion 33. The hole diameter of the second tapered portion 32 is equal to that of the first tapered portion 3.
The contact point with 1 is larger than the outer diameter of the tube 11, and the contact point with the straight portion 33 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. Therefore, if the catheter is pierced into the vein of the patient as an outer needle of the indwelling needle, it will cause pain to the patient. When the taper is smaller than 4 °, the taper is too long, and therefore the tip portion 13 of the catheter 1 becomes long, so the wall thickness is naturally too small. When it is pierced into a catheter or the like, the catheter 1 may be rolled up during piercing, which is not preferable. The 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 portion 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 the step (a), the tube 11 having the cored bar 2 inserted therein is prevented from moving inside the tube 11 by, for example, the needle base 12 and the cored bar 2 in the step (a).
While and are fixed on the same axis, they are inserted into the mold 3 that has been heated to a predetermined temperature in advance until the tube 11 is in a supported state (see FIG. 3). Next, in step (c), the tube 11 is heated for 0.5 to 1.0 second to be softened, and
As shown in FIG. 2, while holding the needle base 12 of the catheter 1, the tip portion 22 of the cored bar 2 protruding downward of the mold 3 is grasped and pulled downward to bring the cored bar 2 to a predetermined position of the mold 3. Push it in further. After maintaining in this state for 5 to 10 seconds, in step (d), the mold 4 that has completed step (c) is cooled by air blow, and then in step (e),
The tube 11 having the cored bar 2 inserted therein is pulled out from the mold 3 that has completed the step (d) (see FIG. 5), and in the step (f), the cored bar 2 is pulled out from the tube 11 and finally the step (key) is performed. ), The tip portion 13 of the tube 11 may be cut at a predetermined position.

As the core bar 2, a core bar as shown in FIG. 6 can be adopted. 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 inner cavity of the pipe 23. The core wire 24 is sufficiently longer than the pipe 23 and has a proximal end. It has a collar 25 having an outer diameter larger than the inner diameter of the pipe 23. Core wire 24
When pulling down the mold 3 in the downward direction, the collar 2 of the core wire 24
5 collides with the pipe 23 and pushes it down, enabling tip processing.

[0012]

As is apparent from what has been described above, by adopting the present invention, it is possible to provide a catheter having a stable distal end shape and a small puncture resistance even in a long catheter or a thin catheter. The physical pain of the patient can be reduced.

[Brief description of 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 cored bar used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Catheter 11 Tube 12 Hub 13 Tip part 2 Core metal 21 Base part 22 Tip part 23 Pipe 24 Core wire 25 Tsuba 3 Mold 31 First taper part 32 Second taper part 33 Straight part

Claims (4)

[Claims] 1. A method for manufacturing a catheter comprising the following steps. (A) Prepare a catheter having an unformed tip composed of a needle base and a tube, and in the tube of the catheter, a base having an outer diameter smaller than the inner diameter of the tube and a smaller size extending at the tip of the base. A cored bar having a tip having an outer diameter is inserted until the tip of the base of the cored bar comes to a position retracted by a predetermined length from the tip of the tube. (A) The tube in 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 while holding the core so as not to move inside the tube. Insert into a preheated mold until the tube is in support. (C) After heating the tube for a certain period of time to soften it, pull the tip of the cored bar from below the mold while holding the needle base of the outer needle so that the tip of the base of the cored bar is at the specified position of the mold. Hold it for a certain period of time. (D) Cool the mold for which the step (C) has been completed for a certain period of time. (E) Pull out the tube with the cored bar inserted from the mold that completed step (d). (F) Pull out the core metal from the tube. (G) Cut the tip of the tube at a predetermined position. 2. A cavity of a mold comprises a first taper portion having a hole diameter larger than an outer diameter of a tube which is reduced in diameter by a relatively large taper following a tube insertion opening having a diameter sufficiently larger than an outer diameter of the tube, A second taper portion that follows the first taper portion and reduces in diameter with a gentle taper, and is smaller than the outer diameter of the tube formed in a tubular shape with the same diameter following the second taper portion,
The manufacturing method according to claim 1, further comprising a straight portion having a hole diameter larger than the outer diameter of the base portion of the cored bar. 3. The core metal comprises a pipe having an outer diameter smaller than the inner diameter of the tube, and a core wire inserted into an inner cavity of the pipe, the core wire being sufficiently longer than the pipe and having a pipe at the base end thereof. The manufacturing method according to claim 1, wherein the flange has an outer diameter larger than that of the inner cavity. 4. The catheter according to claim 1, wherein the tube has a distal end portion with a wall thickness of 0.05 mm or less.