JP2000326384A - Intermittent extruder, intermittent extrusion method and production of catheter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable coating of good quality when a resin is intermittently extruded to cover a core wire. SOLUTION: A ring-shaped projection 25 is formed to the periphery of the nipple adaptor in a crosshead 1 to which a molten resin is supplied or to the inner peripheral surface of the die 21 therein and the nipple adaptor 20 and the die 21 are provided so as to be freely moved to approach and separate mutually. Then, the nipple adaptor 20 and the die 21 are moved in cooperation with a gear pump 3 supplying a molten resin B into the crosshead 1 so as to approach and separate mutually to apply a coating of good quality to a core wire A intermittently.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for intermittently extruding and coating a resin on a core wire, a method for intermittently extruding the resin, and a device made of different materials in the longitudinal direction by using this apparatus and method. The present invention relates to a method for manufacturing a catheter.

[0002]

2. Description of the Related Art Conventionally, a catheter (medical tube) used in the medical field such as a hospital has a distal end portion which, due to its nature, ensures that the distal end reaches a desired diseased part without damaging a living body. Is generally formed of a relatively soft resin material having high flexibility, and the other main body portion is generally formed of a relatively hard resin material in order to surely transmit a pushing torque or the like.

[0003] Such a conventional catheter is
In order to avoid accidents such as the tip falling off from the main body during use and remaining in the living body,
Alternatively, the tip and the main body are integrally formed by extrusion molding so that a step or a gap is not formed at the boundary between the tip and the main body.

[0004] That is, as a conventional method of manufacturing a catheter, for example, on a core wire which is sequentially and sequentially fed out,
After the resin material constituting the catheter tip portion is intermittently extruded and coated at predetermined intervals using an intermittent extrusion device,
The same intermittent extrusion device, or another intermittent extrusion device arranged in series, intermittently extrudes and coats the other resin material constituting the catheter main body portion only on the non-coated portion on the core wire to form a single core wire. The catheter tip and the main body part alternately form a continuous tube material, and then the core wire is extracted from the tube material and a plurality of the tube materials are arranged in the longitudinal direction so that the catheter tip and the main body part form a pair. By cutting into pieces, a plurality of pieces can be obtained at once.

[0005]

The intermittent extruder used in the manufacture of the catheter and the like is, for example, as shown in FIG. 7, a cross head 1 for covering a core wire A with a molten resin B, A gear pump 3 is arranged between the head 1 and an extruder 2 that supplies the molten resin B to the head 1. The drive / stop of the gear pump 3 is repeated at regular intervals, so that the inside of the cross head 1 is The molten resin B is intermittently coated on the passing core wire A.

However, the intermittent operation of the gear pump 3 alone takes time until the coating is completely cut off after the gear pump 3 is stopped, and the time difference is not constant. However, there is a problem that it is not possible to perform satisfactory coating.

More specifically, the molten resin B extruded from the gear pump 3 into the crosshead 1 has a conical nipple 4 for continuously feeding out a core wire A from the tip thereof and a crosshead located around the conical nipple 4 as shown in the figure. Since the nipple 4 is supplied to the tip of the nipple 4 through a resin passage C, which is a gap formed between the main body 5 and the die 6, even if the gear pump 3 is stopped, the residual pressure in the resin passage C causes the molten resin to flow. There is a disadvantage that a part of B leaks to the tip of the nipple 4 as it is and is coated on the core wire A, and the leaked resin adheres to the end of the coating and the end becomes unclear.

As shown in FIG. 8, a pair of extruders 2 and a gear pump 3 for supplying different resins to one crosshead 1 are provided. One molten resin B1 is used as an inner layer, and the other resin B2 is used. Are supplied as outer layers, respectively.
At the same time as the completion of the coating of one resin B1, the other resin B2 is extruded, and a method of alternately arranging different resins by alternately changing the coating thickness of the inner and outer layers at a constant interval has been considered. The transition of the coating could not be made clear, and it was difficult to perform the coating with high accuracy.

Accordingly, the present invention has been devised in order to effectively solve such a problem, and an object of the present invention is to provide high quality coating when intermittently extruding and coating a resin on a core wire. The present invention provides a novel intermittent extrusion apparatus and method, and a method for manufacturing a catheter using the same.

[0010]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a cross head to which molten resin is supplied.
A conical nipple and a die positioned around the nipple with a certain gap therebetween, and the molten resin is flowed from the gap to the nipple tip side, and is extruded and coated on a core wire continuously fed from the nipple tip. An intermittent extruder, wherein a ring-shaped projection is formed around the nipple side or on the inner peripheral surface of the die, and the die or nipple is provided so as to be close to and separated from each other.

When the molten resin is coated by using such an intermittent extruder, the gear pump is driven, and at the same time, the die or nipple is moved close to each other and pressed against the projection while the molten resin is placed on the core wire. When the coating of the molten resin is stopped, by stopping the gear pump and simultaneously moving the die or nipple away from each other to release the residual resin pressure in the resin passage, the residual resin may leak out. As a result, high-quality intermittent coating with a clear boundary between the coated portion and the non-coated portion can be performed.

Accordingly, at least two or more such devices are arranged in the flow direction of the core wire, and a resin made of a predetermined material is extruded and coated on the core wire over a predetermined distance by an upstream extruder. After the coating layer is formed intermittently, a resin having a different composition from the resin of the coating layer is continuously extruded and coated by a downstream extruder at the end of the coating layer, and then the core wire is removed and the tube is lengthened. By cutting in the length direction, a high-quality catheter made of two or more resins having different properties in the length direction can be easily manufactured.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

First, FIG. 1 shows an embodiment of an intermittent extrusion apparatus according to the present invention.

As shown in the figure, this intermittent extruder comprises a crosshead 1 for extruding and coating a molten resin B on a core wire A.
And an extruder 2 for supplying the molten resin B to the crosshead 1, a gear pump 3 located between the extruder 2 and the crosshead 1, and a pushing mechanism 7 attached to the crosshead 1 side. It is configured.

The extruder 2 has a screw 9 rotatably housed in a cylindrical extruder main body 8. The screw 9 is driven by a motor 10 at a predetermined speed via a belt 11 and a speed reducer 12. By rotating and kneading and heating the solid resin material to form a molten resin B,
The molten resin B is extruded from the tip to the gear pump 3 via the connecting pipe 13.

The gear pump 3 includes a pump casing 15 having a flow path 14 for the molten resin B and a pair of gears 16, 16 meshed and housed with the flow path 14 interposed therebetween. Is driven and stopped by a motor (not shown), so that the molten resin B supplied from the extruder 2 side is intermittently supplied to the crosshead 1 side via the connecting pipe 17. A connecting pipe 13 connecting the gear pump 3 and the extruder 2 is provided with a resin pressure gauge 1.
The rotation speed of the motor 10 is controlled so that the extrusion pressure from the extruder 2 is always constant according to the driving / stopping of the gear pump 3.

The crosshead 1 has a cylindrical crosshead body 5 having both ends opened, a sleeve-shaped nipple adapter 20 located in the crosshead body 5 and having a conical tip, and a tip of the nipple adapter 20. The nipple 37 is mounted mainly on the nipple adapter 20 and the die 21 located at a predetermined distance from the tip of the nipple adapter 20 and the nipple 37.

The nipple adapter 20 is fixed by a sleeve 23 having a mounting flange 39 so as to be located at a substantially axial center portion in the crosshead body 5, and a core A fed from a core feeding device (not shown) or the like. The nipple 37 is passed through the nipple 37 and is continuously fed out from the nipple 37 at the tip. Around the distal end of the nipple adapter 20, there is formed a rounded protrusion 25 extending in a ring shape in the circumferential direction.

The die 21 is formed so as to conically surround the distal ends of the nipple adapter 20 and the nipple 37.
A molten resin passage C, which is a conical gap, is formed around the periphery of the core wire A, and the core wire A is passed as it is to adjust the coating thickness of the resin coated on the core wire A. The die 21 is prevented from falling off from the crosshead main body 5 by the die holding nut 24, and is housed in the crosshead main body 5 so as to be movable close to and away from the nipple 37. The crosshead body 5
The crosshead body 5 is heated to a predetermined temperature to prevent the molten resin B inside from being hardened.

On the other hand, the pushing mechanism 7 has a cylindrical die pressing member 26 located in the vicinity of the die 21, a bracket 27 for supporting the die pressing member 26, and a direct engaging member for slidably engaging the bracket 27. An air cylinder 28 for pushing the moving guide 29 and the bracket 27, and a base 30 for fixing the linear moving guide 29 and the air cylinder 28 to the crosshead 1 side are provided. By sliding the bracket 27 and the die pusher 26 toward the crosshead 1, the die 21 can be moved so as to be forcibly pushed in the direction of the nipple adapter 20.

In the figure, reference numerals 32, 32 and 33 denote sleeve 2
3 with the mounting flange 39 and the base 30 in the crosshead 1
Bolt 34 for fixing the molten resin B supplied from the gear pump 3 to the resin passage C in the crosshead 1.
Supply holes for flowing to the side.

Next, an example of the intermittent extrusion method according to the present invention using the intermittent extrusion apparatus having the above-described configuration will be described.

First, when the core A is coated with the molten resin B, as shown in FIG.
1 is pushed in the direction of the nipple 37 so as to move closely, and the inner peripheral surface thereof is formed with a projection 2 formed at the tip of the nipple adapter 20.
After pressing against 5, the gear pump 3 is driven. Then
The molten resin B flowing into the resin passage C passes through between the rounded projection 25 and the die 21 and the nipple 3.
7 and is continuously coated on the core wire A fed from the tip. That is, the protrusion 2
The provision of 5 makes it possible to shorten the narrow path portion of the resin passage C to suppress the flow resistance low, and also it is difficult for eccentricity to occur at the time of coating. The molten resin B coated on the core wire A is coated to a certain thickness depending on the diameter of the through hole 40 formed in the die 21.

Next, after the core resin A is coated with the molten resin B over a predetermined length, when the coating is stopped, the gear pump 3 is stopped as shown in FIG. Return the piston 31 of the air cylinder 28. Then, the die 21 that has been in proximity to the nipple 37 moves away from the nipple 37 due to the residual pressure in the resin passage C, thereby increasing the volume of the resin passage C. The pressure will be released.

As a result, the supply of the molten resin B to the core wire A is instantaneously interrupted, so that the molten resin A does not leak from the resin passage C immediately after the stop of the gear pump 3 as in the prior art, and the coated portion and the uncoated It is possible to achieve a high-quality coating with a clear boundary between the parts. Thereafter, by repeating such an operation at regular intervals in conjunction with the gear pump 3, it becomes possible to intermittently form a high-quality coating on one core wire at regular intervals.

As shown in FIG. 4, two or more intermittent extruders of the present invention are arranged in series with respect to one core wire A, and an outer diameter measuring device for measuring the outer diameter of the coating portion therebetween. 35, a resin made of an arbitrary material is intermittently coated on the core wire A at an arbitrary interval by the above-described intermittent extrusion method using an intermittent extrusion device on the upstream side, and then the end of the coating portion is removed. It is detected by the diameter measuring device 35, the timing is measured from the linear velocity, etc., and then the end of the coating portion is continuously coated with a resin made of another material by an intermittent extrusion device on the downstream side, so that a resin of a different kind in the longitudinal direction is obtained. Can be continuously coated.

Accordingly, the resin material is arbitrarily combined to form a tube made of a resin having different components in the longitudinal direction, and then cut into a plurality of tubes at the boundary, so that the tip and the body as described above are formed. It is possible to easily manufacture a high-quality catheter made of a resin different from the above.

Although the present embodiment has been described with reference to an example in which the projection 25 is formed on the nipple adapter 20 side, the projection 25 may be formed on the die 21 or on both sides, as shown in FIG. As described above, the die 21 is fixed to the crosshead 1 and the sleep 2 of the nipple adapter 20 is fixed.
A moving mechanism such as a pair of air cylinders 36 is provided on the third side, and the nipple adapter 2 is moved by the moving mechanism.
Even if the 0 and nipple 37 sides are moved toward and away from the die 21 side, the same operation and effect as described above can be obtained.

Next, FIG. 6 shows another embodiment of the present invention.

As shown in the figure, in this embodiment, a ring-shaped projection 25 is formed at the tip of the nipple adapter 20 and a resin passage upstream of the projection 25 is formed on the die 21 side as in the above-described embodiment. The overflow hole 38 communicating with C is processed.

In the present embodiment, unlike the intermittent extrusion method of the present invention described above, the die 21 is connected to the projection 2 of the nipple adapter 20 as in the conventional intermittent extrusion method.
Coating is performed in a state of being separated from 5, and when coating is stopped,
By pressing the die 21 against the projection 25 of the nipple adapter 20, the coating on the core wire A is instantaneously stopped.

That is, at the time of coating, the resin passage C
The molten resin B in the inside flows into the tip side of the nipple 37 and a part of the molten resin B is discharged from the overflow hole 38. When the coating is stopped, the die 21 is pressed against the projection 25 of the nipple adapter 20. As soon as the resin passage C is closed, the residual pressure escapes to the overflow hole 38 side, so that the molten resin B in the resin passage C does not leak out from between the die 21 and the projection 25, The flow is stopped instantly. As a result, similarly to the above-described embodiment, it is possible to achieve high-quality coating in which the boundary between the coated portion and the non-coated portion is clear. It should be noted that this method is also effective for a product having an extremely small basis weight and for which it is better to always overflow the die 21.

[0034]

In summary, according to the present invention, the dies or nipples are provided so as to be close to or separated from each other, and the dies or nipples are moved close to or away in conjunction with the gear pump. High quality intermittent coating can be performed. In addition, since it is possible to continuously coat different kinds of materials in the longitudinal direction by using this, it is easy to manufacture a high-quality tube made of a resin having different hardness in the longitudinal direction, such as a catheter. It is possible to exhibit excellent effects such as the ability to perform

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of an intermittent extrusion device according to the present invention.

FIG. 2 is a partial cross-sectional view of a crosshead showing a position of a die at the time of coating.

FIG. 3 is a partial cross-sectional view of the crosshead showing a position of a die when coating is stopped.

FIG. 4 is a cross-sectional view showing an example of a method of manufacturing a tube made of a different resin material in the longitudinal direction, such as a catheter, by combining the intermittent extrusion device according to the present invention.

FIG. 5 is a partial cross-sectional view showing another embodiment of the intermittent extrusion device according to the present invention.

FIG. 6 is a partial cross-sectional view showing another embodiment of the intermittent extrusion device according to the present invention.

FIG. 7 is a cross-sectional view showing an example of a conventional intermittent extrusion device.

FIG. 8 is a cross-sectional view showing another example of a conventional intermittent extrusion device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Crosshead 2 Extruder 3 Gear pump 7 Extrusion mechanism 20 Nipple adapter 21 Die 25 Projection 37 Nipple 38 Overflow hole A Core wire B Molten resin C Resin passage

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Claims (6)

[Claims] 1. A crosshead to which molten resin is supplied, comprising a conical nipple and a die positioned around the nipple with a certain gap therebetween, and from the gap, the molten resin is supplied to the nipple tip side. In an extruder that extrudes and coats a core wire continuously fed from the nipple tip by flowing to the nipple side, or forming a ring-shaped projection on the inner peripheral surface of the die, and forming the die or An intermittent extruder comprising nipples which are movable close to and away from each other. 2. A crosshead to which a molten resin is supplied, comprising a conical nipple and a die positioned at a predetermined gap around the nipple, and the molten resin is supplied from the gap to the nipple tip side. In an extruder that extrudes and coats a core wire that is continuously fed from the nipple tip by flowing through the nipple, a ring-shaped protrusion is formed around the nipple side or the inner peripheral surface of the die, and the die is formed on the die. An intermittent extrusion device having an overflow hole for discharging a resin in a gap, and having a die or a nipple movable close to and away from each other. 3. The intermittent extrusion device according to claim 1, wherein the crosshead includes a pushing mechanism for moving the die or the nipple closer to each other. 4. A crosshead to which a molten resin is intermittently supplied by driving / stopping a gear pump, comprising a conical nipple and a die positioned around the nipple with a predetermined gap therebetween. In the intermittent extrusion method in which the molten resin is caused to flow to the nipple tip side and intermittently extruded and coated on a core wire continuously fed from the nipple tip, the periphery of the nipple side, or the inner peripheral surface of the die The die or nipple is provided so as to be able to approach and separate from each other, and at the time of coating with the molten resin, the gear pump is driven and at the same time, the die or nipple is moved close to each other and pressed against the projection. When the coating of the molten resin is stopped, the gear pump is stopped, and at the same time, the die or the nipple is moved away from the gap so that the gap is removed. Intermittent extrusion method characterized in that the resin pressure is released. 5. A crosshead to which a molten resin is intermittently supplied by driving / stopping of a gear pump, comprising a conical nipple and a die positioned around the nipple with a predetermined gap therebetween. In the intermittent extrusion method in which the molten resin is caused to flow to the nipple tip side and intermittently extruded and coated on a core wire continuously fed from the nipple tip, the periphery of the nipple side, or the inner peripheral surface of the die A ring-shaped projection is formed on the die and an overflow hole for discharging the molten resin in the gap is formed in the die, and the die or nipple is provided so as to be close to and separated from each other. When the gear pump is driven, the die or nipple is moved away from each other, and when the coating of the molten resin is stopped, the gear pump is stopped. The intermittent extrusion method, wherein the die or nipple is simultaneously moved and pressed against the protrusion, and the resin in the gap is discharged from the overflow hole. 6. A method of manufacturing a catheter comprising resin materials of different lengths, wherein at least two or more of the extrusion devices according to any one of claims 1 to 3 are arranged in the flow direction of the core wire. After extruding and coating a resin made of a predetermined material on the core wire over a predetermined distance on the core wire with an upstream extruder to form a coating layer intermittently, the downstream extrusion device forms a coating layer with the resin of the coating layer. A method for manufacturing a catheter, comprising extruding and coating a resin having a different composition continuously at the end of the coating layer, and thereafter extracting the core wire and cutting the tube into a plurality of pieces in the length direction.