JPS609825B2 - Catheter manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION '1' Technical Field The present invention relates to a method for manufacturing a catheter, particularly a method for manufacturing a catheter used for endotracheal tube suction.

BACKGROUND ART As shown in FIG. 1, the outer surface la of a catheter 1 used for suctioning an endotracheal tube during intubation smoothly slides into the Oyo tube (not shown) that has been inserted into the trachea or the like. Satin surface processing to allow insertion,
A so-called embossing process has been applied.

The distal end of the catheter is rounded in order to allow smooth insertion as described above. The code lb is the bottom part. However, the conventional method for processing the insertion tip of a catheter is to heat a mold (or glass mold) 2 made of nickel or the like from the back with a burner 3, as shown in FIG. about 15
When the temperature reaches 0q0, move away the burner 3, immediately press the cut tip of the catheter against the mold 2, and after a few seconds, cool the mold 2 by blowing cold air etc. to shape the tip of the catheter 1. was stabilized, and then the catheter was separated from the mold 2 to form the insertion tip of the catheter as shown in FIG. However, according to this processing method, the area of the outer surface of the catheter shown in FIG. 1, including at least the rounded portion lb, became a mirror surface due to the heat received from the mold. When a catheter having a mirror-like concave portion is inserted into an endotracheal tube, the catheter 1 comes into close contact with the inner surface of the endotracheal tube and cannot be inserted smoothly. In particular, when using a catheter, multiple treatments are often performed on the patient appropriately, quickly, and simultaneously, and if the catheter is not inserted smoothly in such cases, the doctor will become impatient and the treatment will be adversely affected. Alternatively, the insertion force of the catheter may be transmitted to the wall of the trachea through the endotracheal tube, causing extreme pain to the patient. The same effect applies even if a catheter with a mirror-finished end is inserted directly into the trachea or elsewhere. The present invention has been devised in view of the above-mentioned points, and an object of the present invention is to provide a method for manufacturing a catheter having a concave portion that does not eliminate the matte surface of the outer surface of the catheter. (3) Disclosure of the Invention This invention involves forming a tube with a matte surface on the outer surface using a thermoplastic polymer material, and after cutting the required maximum diameter, a pair of electrodes for generating high-frequency oscillation, and a tube between the two electrodes. and an insulator that insulates the mold, one electrode has a columnar part with a tapered tip, and the other electrode has a base end of the columnar part around the columnar part. The insulator is a cylindrical body that forms a machining space extending vertically in the direction, and the insulator is a cylindrical body into which the columnar part is inserted, and the tip is widened from the reduced diameter part of the machining space toward the columnar part. After inserting the cut end surface of the tube into the processing space of the mold, high-frequency oscillation is applied to the mold to the extent that the softening of the tube does not reach the outer surface, and the cut end surface is turned to the inner surface. This method of manufacturing a catheter is characterized in that the tube is cooled after the tube is released and the tip is made into a retracted shape.

In particular, it is preferable to use polyvinyl chloride as the self-thermoplastic polymer material mentioned above. Therefore, according to the processing method of the present invention, the thick center of the distal end of the catheter softens and becomes thermoplastic under the action of thrust. It is possible to obtain a tip end that matches the mold without causing deformation and eliminating the matte surface on the outer surface of the catheter.In addition, unlike conventional processing methods, the mold does not need to be heated, and the heating time can be significantly shortened. In turn, productivity can be significantly improved.

(4) Best Mode for Carrying Out the Invention The shape of the insertion tip of the catheter of the present invention is the same as the conventional one, and therefore, FIG. 1 shows not only the conventional example but also the embodiment of the present invention. Fig. 3 is an explanatory diagram of the method for processing the insertion tip of the catheter of the present invention.As shown in the figure, the mold D used in this processing method has a pair of electrodes that generate high-frequency oscillation and An insulator that insulates between the electrodes, one electrode has a columnar part whose tip is tapered, and the other electrode has a columnar part that is further contracted around the columnar part in the direction of the proximal end of the columnar part. The insulator is a cylindrical body that forms a machining space that rubs, and the insulator is a cylindrical body into which the columnar part is inserted, and the tip part expands from the reduced diameter part of the machining space toward the columnar part. More specifically, with reference to the drawings, the mold D consists of a pair of male and female irons that oscillate high frequencies when they are mated with each other with an insulator 7 made of fluororesin, glass, polycarbonate, etc. in between. A mold that uses a male die 4 and a female die 6 consisting of electrodes, presses the catheter 1 into the processing space 5 formed between the male die 4 and the female die 6, and deforms the pressing end of the force catheter into the shape of the processing space by high-frequency heating. and the male type 4 is
A tapered columnar portion 4a whose peripheral surface is formed as a male taper surface that enters the catheter passage when the catheter 1 is pressed and transforms the inner surface of the catheter into a female taper surface with a larger diameter toward the end surface of the catheter; The male die 4 has a support columnar part 4b extending integrally from the large end of the part 4a and supporting the tapered columnar part 4a, and the insulator 7 is connected to the support columnar part of the male die 4. The tapered columnar part side end surface 7a is attached to the outer surface of the tapered columnar part 4.
It is formed as a male taper surface that coincides with the large flea end of a, and deforms the catheter end surface into a female taper surface that becomes smaller in diameter toward the catheter passage when the catheter is pressed. An insulator 7 is placed in the center of a concave portion (the processing space) 5 defined by a conical curved wall 61 surrounding the tapered columnar portion 4a of No. 4 to form the processing space 5.
It has a shape in which a hole 62 is bored on the outer surface of the wall, and a boundary line 6 where the curved wall 61 and the small hole 62 intersect.
3 coincides with the large end of the male tapered surface of the insulator 7,
The curved wall 61 has a female tapered surface 61a for deforming the outer surface of the catheter into a male tapered surface that tapers toward the end surface of the catheter when the catheter is pressed, and a convex curved surface that tapers at the outer end of the catheter 1. This is a mold formed from a concave curved surface 61b for deforming the shape so that Note that either of the electrodes 4 and 6 may be positive or negative.

In the manufacturing method of the present invention, first, a tube having a satin finish on the outer surface is formed from a thermoplastic polymeric material such as polyvinyl chloride. As a method for making the outer surface a matte surface, for example, there is a method of blowing air onto the outer surface immediately before the cooling step, which is the final step for molding the tube. Then, the tube is cut to a required length to form the catheter 1. Next, the cut end surface of the catheter is pressed against the mold D having the above-described shape with a constant thrust, for example, about 50 mm. In the manufacturing method of the present invention, the catheter 1 is pressed against the mold D while the pair of electrodes 4 and 6 constituting the mold D is pressed.
A high-frequency current of constant strength is passed between the two. Then,
The catheter pressed between the electrodes 4 and 6 is softened by high-frequency heating, and because it is under the action of thrust, it undergoes thermoplastic deformation, that is, a shape change according to the shape of the mold D, as shown in Figure 1. The shape of the tip of the insertion section. As a characteristic of high-frequency heating, the softening of the catheter as described above begins at the thick center of the catheter and progresses toward the outer surface. When the high frequency oscillation time is increased, the softening of the catheter progresses completely to the outer surface, and the matte surface of the outer surface disappears, becoming a mirror surface. Therefore, in the manufacturing method of the present invention, high frequency oscillation is stopped before the catheter softens to the outer surface. Furthermore, if the high frequency oscillation time is too short, the degree of softening of the catheter is small and thrust is applied to the catheter, but the catheter is difficult to undergo good thermoplastic deformation according to the mold D, and processing time is required. In other words, the processed shape is incomplete. Furthermore, the softening and plastic deformation of the catheter is also influenced by the high frequency oscillation output (anode current value). The greater the oscillation output, the faster the catheter softens, and the further the softening progresses. In general, the degree of softening and plastic deformation of a catheter is determined by factors such as the high-frequency oscillation output and oscillation time, the material of the catheter, especially the amount of plasticizer contained in the catheter, the wall thickness of the catheter, the distance between electrodes, and the thrust force used to press the catheter against the mold. Determined by the correlation between Therefore, in the method of the present invention, high-frequency heating is performed under controlled conditions such that the softening of the catheter does not extend to the outer surface.

FIGS. 4, 5, and 6 show the progress of deformation of catheters obtained through experiments due to high-frequency machining.

FIG. 4 shows the state before machining, FIG. 5 shows the state in the middle of machining or is currently unfinished, and FIG. 6 shows the state after machining is completed. According to this experiment, if the catheter is subjected to high-frequency machining under suitable machining conditions, the cut tip surface lc, which is a mirror surface, will be moved to the inner side, and the satined surface of the outer surface will not disappear at the rounded part lb, as shown in FIG. It was confirmed that it was possible to obtain In the method of this invention, as described above, a cathode 1 is placed in the mold D.
The catheter 1 is thermoplastically deformed into a shape corresponding to the mold D by performing high-frequency heating for several seconds while pressing. However, if the catheter 1 is immediately separated from the mold D, the processed shape will not be stable. For this reason, the present invention further includes:
The high-frequency oscillation is stopped and the catheter 1 is kept pressed against the mold D for one to several seconds to cool the catheter 1 and stabilize the processed shape. Example 1
The mold according to the present invention, in which the distance between the electrodes was set to 0.95 mm, was attached to a high-frequency heating device manufactured by Kodensha Electronics Co., Ltd., and the outer diameter/inner diameter was 4.0 x 2.6 mm thick. 0.7m/
Approximately 5 pieces of soft polyvinyl chloride tube is placed in the mold above.
Press the tube with a thrust of 0.0 m, set the frequency to 40.48M, perform high-frequency heating, stop the oscillation, press the tube as it is, allow at least 1 second for cooling to stabilize the processed shape, and generate high-frequency oscillation output ( The graph shown in FIG. 7 was obtained as a result of searching for a thin processing area using the anode current (anode current) and oscillation time as variables.

Example 2 A test material with an outer diameter/inner diameter of 4.7/3.1 and a wall thickness of 0.7 m/m was pressed into a mold with an electrode distance of 0.98 mm and subjected to high-frequency heating. As a result of searching for a suitable machining area, the graph shown in FIG. 8 was obtained (however, other conditions were the same as in Example 1).

Example 3 A test material with an outer diameter/inner diameter of 5.3/3.4 and a wall thickness of 0.95 m/skin was pressed into a mold with an electrode distance of 1.13 m/m, and high-frequency heating was performed. However, as a result of searching for a suitable machining area, the graph shown in FIG. 9 was obtained (however, other conditions were the same as in Example 1).

In addition, the results of measuring the relationship between the tuning scale of the high-frequency heating device manufactured by Kasudensha Electronics Co., Ltd. and the anode current of the mold are shown in the first
It is shown in Figure 0 for reference.

'5} Effects As explained above, the method for manufacturing a catheter of the present invention involves pressing the cutting tip of the catheter against a mold formed by a pair of electrodes that can perform high-frequency heating, while applying high-frequency heating to soften the outer surface of the catheter. This is a configuration in which the cutting tip is thermoplastically deformed into a shape that corresponds to the mold.

Therefore, in the method for manufacturing a catheter of the present invention, a smooth insertion tip can be obtained without eliminating the matte surface on the outer surface of the catheter.

Therefore, when the catheter obtained by the processing method of the present invention is inserted into the patient's trachea through the tracheal tube or directly, the insertion is extremely smooth and the catheter does not pull on the patient's tracheal wall. There will be no blindness that can cause damage to the patient, and as a result, the doctor will not have to worry or be confused during treatment, and the reliability of the doctor will be significantly improved. Furthermore, since the present invention does not involve heating the mold unlike the conventional processing method mentioned at the beginning, the heating time and cooling time can be significantly shortened, and therefore the processing time of the insertion tip can be significantly shortened, resulting in improved productivity. significantly contributes to improvement.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the insertion tip of a conventional catheter and a catheter of the present invention. FIG. 2 is an explanatory diagram of a method of processing the insertion tip of a conventional catheter. Figures 3 to 10 show embodiments of the present invention; Figure 3 is an explanatory diagram of a method for processing the insertion tip of the catheter; Figures 4, 5, and 6 show the insertion tip of the catheter; A cross-sectional view of the tip of the catheter showing the deformation process that occurs. Figures 7, 8, and 9 show that the appropriate machining area was searched under different conditions using the anode current, which is the high-frequency oscillation output, and the oscillation time as variables. Graph, FIG. 10 is a graph showing the relationship between the tuning purpose of the high-frequency heating device used as an example and the anode current. D...Mold, blade...catheter, la...outer surface of catheter, lb...Kind part of the catheter, 4, 6... A pair of electrodes constituting the mold,
5... Processing space constituting the mold, 7... Insulator constituting the mold, 4a... Tapered columnar part ~ 4b... Support columnar part, 7a... Column part side end surface t 61... Curved wall, 61a・
...Female taper surface, 61b...concave curved surface, 62...small hole. Number 2 Figure 3 Figure 4 Figure 5 *6 Figure Fin Wa Figure Traditional 8 Figure Old Man Figure 10

Claims (1)

[Scope of Claims] 1 A tube having a satin finish on the outer surface is formed from a thermoplastic polymer material, and after being cut to a required length, a pair of electrodes for high frequency oscillation and an insulator for insulating between both electrodes. A mold comprising: one electrode having a columnar part whose tip tapers to reduce its diameter, and the other electrode having a diameter reduced in the direction of the proximal end of the columnar part around the columnar part. The insulator is a cylindrical body that forms a space, and the insulator is a cylindrical body that is inserted through the columnar part and has a tip whose diameter increases from a diameter-reduced part of the processing space toward the columnar part. After inserting the cut end of the tube into the processing space of this mold, high-frequency oscillation is applied to the mold to the extent that the tube does not soften to the outer surface, causing the cut end to escape to the inner surface and squeezing the tip. A method for manufacturing a catheter, which comprises cooling the tube after forming the tube into a shape. 2. The method for manufacturing a catheter according to claim 1, wherein the thermoplastic polymer material is polyvinyl chloride.