JPH08322940A - Tube for catheter, manufacture thereof, and manufacturing device - Google Patents

Abstract

PURPOSE: To provide a tube for a catheter which can be manufactured at a low cost, has high reliability, and has a high quality of the appearance form of the flared part thereof. CONSTITUTION: In a tube 11 for a catheter which is formed by thermoplastic resin and has a conical flared part 13 at one end of a tube 12, the flared part 13 is formed in such a manner that the thickness is uniform and both the inner and outer conical surfaces 14, 15 are parallel to each other, and the flared part 13 is integrally formed on the tube 12 without a connecting part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catheter tube made of a thermoplastic synthetic resin and having a conical flare portion at one end, a manufacturing method and a manufacturing apparatus therefor.

[0002]

2. Description of the Related Art Usually, most medical catheters are composed of inner and outer double tubes, and each tube supplies a drug or a contrast agent through a conical flare portion provided at one end thereof. Are connected. Therefore, the tube connection requires certainty and a good sealing property, and therefore the flare portion is required to have high quality and high accuracy. The following two methods have been conventionally used for processing such flare portions.

The first flare processing method is, as shown in FIG. 10, one end of a tube 4 made of a thermoplastic synthetic resin by a slide table 3 on a conical flare molding surface 2 provided at the tip of a flare expansion body 1. To press and soften one end of the tube 4 by the heater 5 for heating the tube and the sensor 6 for adjusting the heating temperature embedded in the flare expansion body 1 to expand it conically along the flare molding surface 2. Is a method of molding the flare portion 7. This method has a low production cost because the apparatus is simple, and is highly reliable because the flare portion 7 is integrally formed at one end of the tube 4.

Although not shown in the drawings, the second flare processing method uses an injection molding method, in which a pellet-shaped thermoplastic synthetic resin is melted, and the molten thermoplastic resin is injected into a mold for injection molding at high pressure. After sending and molding flare parts,
This is a method of connecting the flare parts to one end of a tube by an adhesive or heat welding. This method is suitable for the case where the shape of the appearance of the flare is complicated or when the quality of the appearance is important because a desired flare shape product can be obtained with high accuracy depending on the shape of the mold.

[0005]

However, the above-described conventional flare processing method has the following problems. In the first flare processing method, there is a problem that the molding temperature condition of the flare portion 7 is very narrow. This will be described based on the flare processing experiment results using the polyethylene tube shown in Table 1.

[0006]

[Table 1]

If the set temperature is lower than 70 ° C., it does not soften and cannot be expanded, and if it is 70 to 85 ° C., the softening is insufficient and cracks occur during expansion. On the contrary, when the set temperature exceeds 115 ° C., the flare expansion body 1 is in a semi-molten state from the point of contact and does not expand, and becomes a dumpling state on the spot. Therefore, the flare processable region is about 87 to 115 ° C., but the temperatures near 87 ° C. and 115 ° C. are actually unstable regions, and the stable flare processable temperature range is 90 to 105 ° C. Furthermore, 90-
The flare portion 7 molded at 103 ° C. has a drawback that it contracts due to residual stress at the time of mold release, and the shape at the time of molding cannot be completely maintained. Therefore, the temperature range for obtaining the flare portion 7 which is satisfactory to some extent is about 104 to 105 ° C., but even in this case, a slight shrinkage occurred.

As described above, the problem that the molding temperature condition is extremely narrow and the contraction at the time of mold release is unavoidable is that the resin having a high crystallinity, that is, the characteristic of suddenly softening and melting near the melting point with respect to the temperature rise. Is more prominent in a resin showing, for example, polyethylene, polypropylene, polyethylene terephthalate, polyvinyl alcohol, polyamide and the like.

Next, there is a problem that the quality of the external shape of the molded flare portion 7 is not always sufficient. That is, in the first method, as shown in FIG. 10, one end of the tube 4 having a constant wall thickness is forcibly expanded into a conical shape by the flare expansion body 1, so that the flare portion 7 is fleshed by increasing the surface area. As shown in FIG. 11 (conventional product), the thickness is reduced from the flare expansion start end A toward the end B, and as shown in FIG.
Is formed. The flare expansion start end A and end B of the conventional catheter tube are shown in FIG.

As shown in FIG. 14, the conical angle α of the outer conical surface of the flare portion 7 becomes smaller than the conical angle β of the inner conical surface due to the thinning of the wall thickness. There is unevenness in the tightening of the flare portion 7 between 10 and the sealing performance deteriorates.

Further, due to the roundness 8 at the tip of the flare portion 7, as shown in FIG. 15, the area f sandwiched by both fastening fittings 9 and 10 is a trapezoidal edge flare portion (shown by a dotted line in the figure). Area F, and the sealability is further reduced.

Further, since the amount of change in the thickness of the flare portion 7 and the roundness 8 at the tip are not controlled and molded, the shape of the flare portion is subtly different and stable even if molded under the same conditions. It is difficult to obtain the shape. for that reason,
It is difficult to use the tightening fittings 9 and 10.

Next, in the second flare processing method, the mold part of the injection molding machine is expensive and the equipment becomes large, so that the production cost is drastically increased and the flare part is made into parts. Therefore, there is a problem that a connecting step with the tube is required. In particular, in connection with the tube, there are cases where adhesion is difficult depending on the material. For example, when the material is polyethylene, a connection method by heat welding is adopted because there is no good adhesive. However, with cross-linked tubes and resins with strong cohesive force due to ionic groups such as ionomers, it is difficult to obtain sufficient adhesive strength even by heat welding, and it is easy to connect the flared parts made into parts to the tube. is not. Even if the connection can be made by some method, it is inevitable that the connection point is inferior in reliability to the one in which the flare portion is integrally formed at one end of the tube by the first flare processing method.

An object of the present invention is to solve the problems of the conventional techniques as described above and to provide a low cost, highly reliable catheter tube having a high quality appearance of the flare portion. To do.

[0015]

In order to achieve the above object, the catheter tube of the first invention is made of a thermoplastic synthetic resin and has a conical flare portion at one end of the tube. The flare portion has a uniform thickness and its inner and outer conical surfaces are formed parallel to each other, and the flare portion is integrally formed with the tube without a connection portion. . A cylindrical flange may be formed at the tip of the flare portion in order to enhance the mountability to the tube connecting tightening fitting.

A second aspect of the present invention is a method for producing a catheter tube, which is a method for producing a catheter tube according to the first aspect of the present invention, in which the tube guide is axially provided from the top of the conical flare molding surface. An outer die is fitted on the outer periphery of a flare extension body formed by projecting a rod to form a flare molding space between the flare extension body and the outer die.
A second step of inserting a tube made of a thermoplastic synthetic resin into the outer circumference of the tube guide rod and introducing the tube into the flare molding space, and the flare molding space while heating and melting the end of the introduced tube. The third step of filling the inside of the flare portion to form the flare portion, the fourth step of fixing the shape of the flare portion by cooling and solidifying after the completion of filling, and the tube having the flare portion formed at the end of the external metal. It has a configuration including a fifth step of releasing from the mold and the flare expansion body.

Furthermore, the catheter tube manufacturing apparatus of the third invention is an apparatus for carrying out the manufacturing method of the second invention, and has a conical flare molding surface on the outer periphery,
A flare extension body in which a tube guide rod is projected in the axial direction from the top of the flare molding surface, and a tube heating heater and a heating temperature adjusting sensor are embedded therein, and a hollow split mold that can be opened and closed. An outer metal mold having a flare molding concave portion in a portion, holding an outer periphery of the flare expansion body to form a flare molding space between the flare molding concave portion and the flare molding surface, and a tube The slide table is inserted into the outer periphery of the guide rod and pushed into the flare forming space.

[0018]

In the present invention, since the flare portion is molded by injection molding in a conical flare molding space formed between the flare expansion body and the outer mold, the flare portion has a uniform thickness and its Both the inner and outer conical surfaces are formed parallel to each other, and the cross-sectional shape thereof has the same trapezoidal edge shape as the flare molding space (see FIGS. 1 and 2 corresponding to the examples described later).

Therefore, when the flare portion is attached to the tube connecting tightening fitting as shown in FIG. 2, there is no unevenness in tightening of the tightening fitting, and the area F sandwiched by both tightening fittings is the area in the conventional flare portion ( 12
It is wider than f) in (b). Therefore, the sealing property is superior to the conventional flare part.

Further, since the flare portion is integrally formed at one end of the tube without the connection portion, the reliability of the tube is high. Further, since the flare portion is formed in the same manner as the injection molding, the quality of the outer shape of the flare portion is extremely high like the injection molded product.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a sectional view of a catheter tube showing an embodiment of the present invention. As shown in FIG. 1, the catheter tube 11 has a conical flare portion 13 integrally formed at one end of a tube 12 made of a thermoplastic synthetic resin such as low-density polyethylene without a connecting portion. .

The flare portion 13 has a uniform thickness and its inner and outer conical surfaces 14 and 15 are formed in parallel with each other. Therefore, the cone angles of both conical surfaces 14 and 15 are equal to each other,
is θ. The cross-sectional shape of the flare portion 13 has the same trapezoidal edge shape as the flare molding space 34 (FIGS. 4 and 5) described later.

The catheter tube 11 has extremely high reliability because the flare portion 13 is formed integrally with the tube 12. In addition, as shown in FIG. 2, when the flare portion 13 is attached to the tube connecting tightening fittings 9 and 10, the flare portion 13 has a uniform thickness and both conical surfaces 1.
Since 4 and 15 are formed in parallel with each other, there is no unevenness in tightening, and the area F sandwiched by both tightening fittings 9 and 10 is wide, so that the sealing property is good.

The catheter tube 11 can be manufactured by a manufacturing apparatus as shown in FIG. In this manufacturing apparatus, a flare extension body 22, an outer mold 23, and a slide table 24 are attached to a support base 21.

A front bearing 25 and a rear bearing 26 are erected on the support base 21, and a support shaft 27 is provided between the two bearings 25, 26. The flare extension 22 includes a tube heating heater 28 and a heating temperature adjusting sensor 29.
It is a brass rod-shaped body having a good heat transfer property and having a base portion implanted in the upper portion of the front bearing 25. This flare extension 2
As shown in the enlarged view of FIG. 4, 2 has a conical flare molding surface 30 with a cone angle of θ on the outer periphery of the tip end, and a tube guide rod 31 made of stainless steel projects axially from the top of the flare molding surface 30. It is set up. The flare molding surface 30 is coated with a fluorine-based resin such as Teflon (registered trademark of du Pont) or a release agent in order to improve releasability.

The outer mold 23 is a hollow split mold that can be opened and closed.
It is made of Teflon, which is excellent in mold releasability and heat resistance, and is mounted on the support shaft 27 via the support 32 so that the position of the flare extension 22 can be adjusted. As shown in an enlarged view in FIG. 4, the outer mold 23 has a conical flare forming recess 33 having a cone angle of θ in the hollow portion, and when the outer periphery of the flare expansion body 22 is held, the flare forming is performed. A conical flare molding space 34 having a cone angle of θ is formed between the recess 33 and the flare molding surface 30. The flare molding space 34 has a trapezoidal edge cross section. The slide table 24 is
The tube 12 is inserted into the outer circumference of the tube guide rod 31 and pushed into the flare molding space 34.
It is mounted on 7 so as to be movable in the axial direction.

In order to manufacture the catheter tube 11 with the above-mentioned manufacturing apparatus, first, as shown in FIG. 4 in the first step, the outer mold 23 is closed and positioned at a predetermined position with respect to the flare expansion body 22, The outer mold 23 holds the outer periphery of the flare expansion body 22 to form a flare molding space 34. The positioning and centering of the outer mold 23 can be easily achieved by providing a hollow portion of the outer mold 23 with a recess that can be fitted into the cylindrical portion of the flare expansion body 22, as shown in the figure. .

Next, in the second step, as shown in FIG. 3, the tube 12 is set on the slide table 24, and the flare extension 22 is heated to 150 ° C. by the heater 28 and the sensor 29. Then, as shown in FIG. 5, the slide table 24 is moved to move the tube 1
The second end is inserted into the outer circumference of the tube guide rod 31, the melting margin is set to 20 mm, and then the tube 12 is introduced into the flare molding space 34 at a speed of 40 mm / min.

In the next third step, as shown in FIG. 6, the end of the introduced tube 12 comes into contact with the flare molding surface 30 and begins to melt by heat transfer from the heater 28. The molten resin is pushed into the flare molding space 34 by the tube 12 that is continuously introduced, the fluidity is increased by further heating, and the flare molding space 34 is filled by the pressure of the molten resin that is continuously pushed. Then, the flare portion 13 as shown in FIG. 7 is formed.

Next, in the fourth step, as shown in FIG. 7, introduction of the tube 12 is stopped at the same time as the filling is completed, and the flare portion 13 in the flare molding space 34 is solidified by cooling to 80 ° C. by air cooling. And fix the shape.

In the final fifth step, as shown in FIG. 8, the outer mold 23 is opened and the flare portion 13 is attached to the end of the tube 12.
The catheter tube 11 molded with is separated from the outer mold 23 and the flare expansion body 22 and taken out. The thickness of the flared portion of the obtained catheter tube 11 is shown in FIG.
As shown in No. 1 (product of the present invention), the flare expansion start end A to end B was uniform. The flare expansion start end A and end B of the catheter tube of the present invention are shown in FIG.

The present inventors repeated the above operation 60 times, but were able to obtain the catheter tube 11 of the same quality with good reproducibility. Moreover, it was possible to obtain the flare portion 13 having a quality comparable to that of the injection molded product. Also,
As for the temperature condition, the flare portion 13 could be molded in a wide range of 135 to 165 ° C.

Although the flare portion 13 has a shape as shown in FIG. 1 in the present embodiment, it is not limited to this, and as another embodiment shown in FIG. A cylindrical flange 16 may be integrally formed at the tip of 13. As a result, the mountability to the fastening fittings 9 and 10 is improved.

Further, in order to make the present invention more effective,
Instead of heating by the heater 28, the outer die 23 may be heated, or these may be used together. Further, the tube guide rod 31 may have a tapered tip for facilitating insertion of the tube 12, and may be made of a ceramic material or a hollow material to reduce heat transfer from the flare expansion body 22. You may make it a tube and let heat escape. Furthermore, in order to prevent the tube 12 from buckling when the tube 12 is introduced into the flare molding space 34, a cooling mechanism may be provided to cool the tube and strengthen its rigidity.

[0035]

As described above, in the present invention, the end of the tube introduced into the flare molding space is heated to the melting point, and the flare portion is formed by injection molding. Therefore, when the flare portion is cooled and solidified, residual stress does not remain, the flare portion has a uniform thickness and its inner and outer conical surfaces are formed parallel to each other, and its cross-sectional shape is the same as that of the flare molding space (preferably trapezoidal shape). Edge-like).

When the flare portion thus obtained is attached to the tube fitting fastening fitting, the fastening fitting has no unevenness in tightening, and the area sandwiched by both fastening fittings is wider than the area of the conventional flare portion. Therefore, it exhibits excellent sealing properties.

Further, since the flare portion is integrally formed at one end of the tube without the connection portion, the reliability of the catheter tube is enhanced.

Furthermore, since the flare portion is formed by the injection molding procedure, the variation in the outer shape of the flare portion is dramatically improved.

Furthermore, since the structure of the manufacturing apparatus is simple, the manufacturing cost of the catheter tube can be low.

If a cylindrical flange is formed at the tip of the flare portion, the mountability of the flare portion to the tube connecting tightening fitting is improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a catheter tube of the present invention.

FIG. 2 is a cross-sectional view showing a state in which the flare portion of the catheter tube of the present invention is attached to a fastening fitting.

FIG. 3 is an overall configuration diagram of a manufacturing apparatus of the present invention.

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

FIG. 5 is an explanatory view showing a second step of the manufacturing method of the present invention.

FIG. 6 is an explanatory view showing a third step of the manufacturing method of the present invention.

FIG. 7 is an explanatory view showing a fourth step of the manufacturing method of the present invention.

FIG. 8 is an explanatory diagram showing a fifth step of the manufacturing method of the present invention.

FIG. 9 is a cross-sectional view showing another embodiment of the catheter tube of the present invention.

FIG. 10 is a cross-sectional view for explaining an example of a conventional manufacturing method.

FIG. 11 is a view showing a change in wall thickness from the expansion start end to the expansion end of the flare portion of the conventional catheter tube and the catheter tube of the present invention.

FIG. 12 is a view showing an expansion start end A to an end B of a flare portion of a conventional catheter tube.

FIG. 13 is a view showing an expansion starting end A to an end B of the flare portion of the catheter tube of the present invention.

FIG. 14 is a cross-sectional view showing a state in which a flare portion of a conventional catheter tube is attached to a fastening fitting.

FIG. 15 is a cross-sectional view showing a state in which a flare portion of a conventional catheter tube is attached to a fastening fitting.

[Explanation of symbols]

11 Tube for catheter 12 Tube 13 Flare part 14 Inner conical surface 15 Outer conical surface 16 Collar part 22 Flare expansion body 23 Outer mold 24 Slide table 28 Heater 29 Sensor 30 Flare molding surface 31 Tube guide rod 33 Flare molding concave 34 34 Flare Molding space

Claims (4)

[Claims] 1. A catheter tube made of a thermoplastic synthetic resin and having a conical flare portion at one end of the tube, wherein the flare portion has a uniform thickness and its inner and outer conical surfaces are parallel to each other. At the same time, the catheter tube is characterized in that the flare portion is integrally formed with the tube without a connection portion. 2. The catheter tube according to claim 1, wherein a cylindrical collar portion is formed at the tip of the flare portion. 3. An outer mold is fitted on the outer periphery of a flare expansion body formed by projecting a tube guide rod in the axial direction from the top of a conical flare molding surface, and these flare expansion body and outer mold are connected to each other. A first step of forming a flare molding space between the two, and a second step of inserting a tube made of a thermoplastic synthetic resin into the outer periphery of the tube guide rod and introducing the flare molding space into the flare molding space.
A third step of forming a flare part by filling the flare forming space while heating and melting the end of the introduced tube; and fixing the shape of the flare part by cooling and solidifying after the completion of filling. A method for producing a catheter tube, comprising a fourth step and a fifth step of releasing the tube having the flared portion formed at the end from the outer mold and the flare expansion body. 4. A conical flare molding surface is provided on the outer periphery,
A flare extension body in which a tube guide rod is projected in the axial direction from the top of the flare molding surface, and a tube heating heater and a heating temperature adjusting sensor are embedded therein, and a hollow split mold that can be opened and closed. An outer metal mold having a flare molding concave portion in a portion, holding an outer periphery of the flare expansion body to form a flare molding space between the flare molding concave portion and the flare molding surface, and a tube A device for manufacturing a catheter tube, comprising: a slide table that is inserted into the outer periphery of a guide rod and pushed into the flare molding space.