JP2001269411A - Tube for catheter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tube for catheter which is formed by causing two resins having different hardness to continue in a longitudinal direction in which the reliability of junction is raised by relaxing the changes of hardness on the boundary surface of the resin. SOLUTION: A tube for catheter 12 which is formed of the first resin (a rigid portion 12a) having different hardness continuing along the longitudinal direction and the second resin (a flexible portion 12b), wherein for a transition portion 12c between the first resin and the second resin, the composition ratio of the first resin and the second resin in a section varies along the longitudinal direction so that stiffness gradually increases or decreases along the longitudinal direction and a mixing region 12d of both the resins is formed on the boundary surface between the first resin and the second resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medical catheter, and more particularly, to a catheter tube made of extruded products of two kinds of resins having different hardnesses, and a method and an apparatus for manufacturing the same.

[0002]

2. Description of the Related Art A medical catheter is a resin molded body having a length corresponding to a portion to be used. A hand portion is made of a resin material having relatively high rigidity. It is formed with. When manufacturing a catheter tube made of two kinds of resins having different hardnesses, the two kinds of resin are sequentially supplied to an extrusion die to form a continuous tube.

FIG. 14 is a horizontal sectional view of a conventional extrusion die for extruding a catheter tube by switching a plurality of resins. The extrusion die 30 includes a die 32 having an extrusion hole 31, a die holder 34 for holding the die 32 by bolts 33, and a mandrel 35 mounted facing the extrusion hole 31. The mandrel 35 includes an inner layer mandrel holder 36 and an outer layer mandrel holder 3.
7, and is fixedly held in the die holder 34. Each of the inner and outer mandrel holders 36 and 37 has a cylindrical or conical shape, and a guide cavity 38 for supplying resin to the mandrel 35 is formed along the entire peripheral surface of the cylindrical or conical tip.

A resin (hard first resin having relatively high rigidity) and B resin (soft second resin having low rigidity) having different hardnesses are supplied to both outer sides of the die holder 34 by switching. Switching devices 39 and 40 are provided. Each of the switching devices 39 and 40 is provided with an A
It is connected to the resin supply port 43 and the B resin supply port 45.
The die holder 34 and the switching devices 39 and 40 are provided with a heater 47 for maintaining the resin in a softened state.

The switching device 39 for supplying the resin A includes a switching valve 4
1 and an A resin inlet 42 to which an A resin extruder (not shown) is connected. The resin A is supplied to the resin supply port 43 of the die holder 34 by the rotation of the switching valve 41. The A-resin supplied to the A-resin supply port 43 is supplied to a groove (not shown) of the outer layer mandrel holder 37 through the communication path 44, and the guide cavity 38 at the distal end portion is passed through the groove.
And is drawn out of the extrusion hole 31 through the annular space on the outer surface of the mandrel 35.

Similarly, the B resin is changed by the switching device 40
It is supplied to the guide cavity 38 of the inner layer mandrel holder 36 through the B resin supply port 45 and the communication passage 46,
The mandrel 35 is drawn out of the extrusion hole 31 through the annular space on the outer surface.

A resin and B are switched by switching devices 39 and 40.
The resin is alternately switched and selected, and supplied into the die holder 34 sequentially and sequentially. At this time, the resin not selected is transferred to the switching valve 41 of each switching device 39 or 40.
From the outside through a resin outlet (not shown).
At this time, a part of the resin not selected is supplied to the resin supply ports 43 and 45 in the switching devices 39 and 40 and the die holder 34, the communication passages 44 and 46, the inner and outer mandrel holders 36 and It remains in the groove on 37 and in the guide cavity 38 and then stays there until it is switched out.

The mandrel 35 is fixed to the tip of a shaft 48. The axis of the shaft 48 is coaxial with the axis of the extrusion hole 31 of the die 32. This shaft 48 is fixed in the inner layer mandrel holder 36,
It is fixed and held in the die holder 34. At the time of use, for example, the core is inserted along the shaft 48, the mandrel 35 and the axis of the extrusion hole 31, and the extrusion hole 31 is formed around the core.
And the molten resin selected by the switching device is supplied to extrude the tube.

The mandrel 35 has a conical front portion and a cylindrical tip portion engaged in the extrusion hole 31 of the die 32, and is annular between the outer surface of the mandrel 35 and the inner surface of the extrusion hole 31 (the entrance portion has a conical shape). After that, a space having a cylindrical shape on the downstream side is formed. The resin flows out of the extrusion hole 31 through the annular space. The mandrel 35 guides the resin flowing along the surface of the mandrel to the extrusion hole 31 and has a smooth outer surface of the mandrel and an inner surface of the extrusion hole to make the flow of the resin a steady laminar flow. The thickness of the space is kept constant.

In such an extrusion die, by supplying the hard and soft resins alternately, a catheter tube in which the hard and soft resins are joined in order along the longitudinal direction is formed. This tube is cut into a set of hard and soft parts after manufacture to form a catheter.

The joint between the hard A resin and the soft B resin in such a tube, because the resin sequentially passes through an annular space having a constant thickness between the outer surface of the mandrel and the inner surface of the extrusion hole of the die, The flow velocity in the central part of the space is high, the flow velocity in the part in contact with the wall surface is low, and the profile of the flow velocity distribution inevitably causes the resin flowing later to wedge into the thickness of the previous resin in a wedge shape. Become.

FIG. 15 shows a state of a cross section of such a junction boundary. In FIGS. 7A and 7B, the resin distribution shape of the cross section of the tube 50 is a shape in which the A resin 52 bites into the B resin 51 in a wedge shape to form a joining boundary surface. (B) In the figure, when the B resin 51 is drawn out after molding, the outer diameter is reduced by the tensile force (the inner diameter is constant depending on the diameter of the core material).

[0013]

However, in a conventional extrusion die for a catheter tube, since the outer surface of the mandrel and the inner surface of the extrusion hole are smooth and the thickness of the annular space through which the resin flows is constant, there is a problem. The joint interface between the two types of resins is almost completely divided into a wedge shape by two resin materials, and the two resin materials are hardly mixed at the interface. For this reason, the bonding strength of the two resins at the boundary surface is weak, and there is a possibility that peeling may occur. In addition, the local bending when the bending stress is applied due to a large change in strength increases, and the reliability of the bonding is increased. There was a problem in terms.

If the difference in hardness is large, the tube on the soft side becomes thinner when the tube is drawn out during the molding process, and the outer shape is locally constricted, particularly at the joint, and the strength may be reduced. .

The present invention has been made in consideration of the above-mentioned prior art, and is intended to form a catheter tube formed by continuously joining two kinds of resins having different hardnesses in the longitudinal direction so that the change in hardness at the resin boundary surface is moderated. It is an object of the present invention to provide a catheter tube with improved reliability, a method for manufacturing the same, and a manufacturing apparatus.

[0016]

According to the present invention, there is provided a catheter tube formed of a first resin and a second resin having different hardnesses which are continuous in a longitudinal direction. The transition between the second resin and the second resin is such that the composition ratio of the first resin and the second resin in the cross section changes along the longitudinal direction so that the stiffness gradually increases or decreases along the longitudinal direction. Provided is a catheter tube, wherein a kneaded region of both resins is formed at a boundary surface between the resin and the second resin.

According to this configuration, at the transition from the first resin to the second resin, the composition ratio of the two resins in the cross section of the ring-shaped tube changes so as to gradually increase or decrease with respect to one resin, and the two resins are combined. Since the material is kneaded at the interface, a rapid change in the rigidity at the interface is suppressed, and the reliability of bonding is improved.

Further, in the present invention, as a method for manufacturing the catheter tube, a die having an extrusion hole, a die holder for holding the die, and a mandrel mounted in the die holder and engaged with the extrusion hole are provided. In a method of manufacturing a catheter tube formed of a first resin and a second resin having different hardnesses that are continuous in a longitudinal direction using an extrusion die having the same, a flow path area is changed with respect to a resin passing through the extrusion hole. While the first
Provided is a method for manufacturing a catheter tube, wherein the resin and the second resin are supplied alternately.

According to this configuration, since the flow area of the resin passing through the extrusion hole changes and the resin flows in a turbulent flow or in a state close to the turbulent flow, when the different types of resins are supplied alternately and continuously, the first flow is changed. The resin put in the resin and the resin put in later are kneaded at the boundary, and a kneaded region where both resins are mixed and stirred is formed, so that the reliability of joining is improved.

Further, according to the present invention, as the apparatus for manufacturing a catheter tube, a die having an extrusion hole, a die holder for holding the die, a mandrel mounted in the die holder and engaged with the extrusion hole are provided. A kneading means is provided between a die and a mandrel at the entrance of the extrusion hole in a manufacturing apparatus for a catheter tube provided with an extrusion die having the following.

According to this structure, the die surface and the mandrel surface at the inlet of the extrusion hole are not merely smooth surfaces but are provided with a resin kneading means. Since the resin and the resin added later are kneaded at the boundary, and a kneaded region where both resins are mixed and stirred is formed, the reliability of bonding is improved.

In a preferred configuration example, the kneading means is characterized by comprising a convex portion, a concave portion or a step portion formed on the die and / or the mandrel.

According to this configuration, the turbulent flow or a state close to the turbulent flow is formed by changing the area of the flow path of the resin by the convex, concave, or step portions formed on one or both of the die and the mandrel. Are kneaded at the resin boundary portion.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an overall configuration of a catheter tube manufacturing apparatus to which the present invention is applied, and FIG.
Is a plan view, and (B) is a side view. The core wire feeder 1 supplies a core wire having an inner diameter of a tube to be formed to an extrusion die 2. On both sides of the extrusion die 2, an A extruder 3 for supplying a hard A resin and a B extruder 4 for supplying a soft B resin are provided.
At the outlet side of the extrusion die 2, a cooling water tank 5 for cooling the formed and drawn tube is provided. A take-up machine 6 and a take-up machine 7 are provided at the outlet side of the cooling water tank 5. A resin tube made of resin A and resin B extruded on a core wire by the extrusion device 2 is pulled together with the core wire by a pulling machine 6 with a predetermined tension, and slits (not shown) formed at both ends of the cooling water tank 5 are formed. Through the cooling water tank 5 and is solidified at a predetermined hardness (shape is stabilized). Cooling water tank 5
Is always supplied with overflowing water. Pickup machine 6
The outer diameter of the tube is determined according to the tensile strength of the tube. The inner diameter of the tube is determined by the outer diameter of the core wire. The tube solidified to a predetermined hardness state is wound up by the winder 7.

In such an apparatus, the A tube and the B resin are alternately switched and continuously supplied to continuously form catheter tubes having different hardnesses in the longitudinal direction.

FIG. 2 is an external view showing an example of a catheter using the tube of the present invention. The catheter 8 includes a hub 9 serving as an insertion port for a contrast agent and a guide wire, a strain relief 10 for protecting a tube of the hub mounting portion, and a catheter tube 11. Catheter tube 1
1 is formed by a hand side portion 11a made of hard A resin, a tip portion 11b made of soft B resin, and a transition portion 11c between which the hardness gradually changes.

FIGS. 3A and 3B are a cross-sectional view of a catheter tube according to the present invention and a graph of its rigidity (hardness). (A) As shown in the figure, the catheter tube 12 has a hard portion 12a made of only A resin.
And a soft portion 12b made of only B resin, and a transition portion 12c in the middle. In the transition portion 12c, the A resin bites into the B resin side in a wedge shape, and a boundary layer kneading portion 12d in which both resins are kneaded is formed on the boundary surface. In the transition portion 12c, as shown in FIG. 6B, the rigidity of the tube gradually changes from 100% hardness of the A resin to 100% hardness of the B resin.

FIG. 4 shows the transition section 12 of the tube 12 of FIG.
3 shows a cross section of a portion c. (A) is a figure in which the wedge shape is formed in an annular shape continuously in the circumferential direction of the tube tube wall, and is formed by the mandrel of FIGS. 5 and 6 and FIGS. FIG. 7B shows the wedge shape divided into a plurality of pieces in the circumferential direction, and each of the divided parts is sharply formed like a spear tip, and is formed by a mandrel shown in FIG. 7 described later. In each case, a boundary layer kneading portion 12d is formed between the hard portion 12a made of the A resin and the soft portion 12b made of the B resin.

FIGS. 5 to 11 show examples of a mandrel to be mounted on an extrusion die of a catheter tube having the above-mentioned kneading layer. In each case, the extrusion mold 3 shown in FIG.
0 in the same extrusion mold as the mandrel 35 and / or
Alternatively, the kneading portion is formed by changing the shape of the die 32. In each of the figures, (A) shows the mandrel assembled state, and (B) shows the mandrel alone.

The mandrel 13 in FIG. 5 has an annular recess 19 along the circumferential direction of the conical surface for guiding the resin. The mandrel 13 is fixed to the tip of the shaft 14 by, for example, a screw connection, and the conical portion of the mandrel and the cylindrical portion on the tip side are inserted into the extrusion hole 21 of the die 17 and are annular (the inlet side is conical and the tip side is cylindrical). A (cylindrical) resin passage 18 is formed. In the resin passage 18, an inner resin supply cavity 15 and an outer resin supply cavity 16 are provided.
A resin and B resin are supplied alternately and continuously.
In this example, the inlet of the cylindrical resin passage 18 (resin junction)
The enlarged channel portion 20 is formed by the concave portion 19 of the mandrel and the corresponding concave portion on the die side, and the channel immediately after the enlarged portion 20 is narrowed to form the reduced channel portion 22. . By alternately flowing the resin A and the resin B while changing the flow path area in this manner, the two resins are kneaded at the boundary portion, and the above-described boundary layer kneading portion 12d is formed. In addition, the flow path enlarged portion 20 may be formed by providing a concave portion on either the mandrel side or the die side.

The mandrel 13 shown in FIG. 6 has three rows of annular projections 23 provided on the conical surface as a resin kneading means. The resin flow path area also changes due to such protrusions 23, and the two resins are kneaded at the boundary, thereby forming the boundary layer kneading portion 12d.

The mandrel 13 shown in FIG. 7 has three rows of annular projections 2 on its conical surface as a means for kneading the resin.
3 and a plurality of grooves 24 inclined in a certain direction are formed in the annular convex portions in two rows on the upstream side in a circumferential direction. The inclination directions of the grooves 24 of the first two rows of the annular projections 23 are formed in mutually opposite directions and alternately shifted. By forming the groove 24 in this manner, the wedge-shaped boundary between the two resins is divided according to the number of grooves, and becomes a plurality of spear-tip-shaped boundaries, the cross section of which is as shown in FIG. Depending on the shape of multiple islands, or material and flow velocity,
A plurality of spiral stripes are formed which advance in the axial direction while traveling from the inner surface to the outer surface of the tube cylinder wall. By forming such a groove 24, the kneading action of the boundary portion is promoted, and the boundary layer kneading portion 12d is reliably formed.

The mandrel 13 shown in FIG. 8 is provided with a double screw 25 projecting from the conical surface thereof as a resin kneading means. It is desirable that this screw be a subflight screw having a thread groove formed along the top thereof in order to enhance the kneading effect.

The mandrel 13 shown in FIG. 9 has a structure in which three rows of steps 26 are formed on the conical surface as a means for kneading the resin.

The mandrel 13 shown in FIG. 10 is provided with two annular convex portions 23 on the conical surface as a resin kneading means, and has a convex portion on the front die side corresponding to the rear convex portion 23. Is provided. By providing the protrusions on the die side and the mandrel side in this manner, a vortex is generated in the resin flow, and the kneading action is promoted.

The mandrel 13 shown in FIG. 11 forms two rows of steps 26 on the conical surface as resin kneading means, and forms steps on the die side corresponding to each step 26 so that the resin flow is reduced. And the kneading action of the resin is increased by increasing the turbulence of the resin.

FIG. 12 is a graph of bending strength (rigidity) showing rigidity of a catheter tube made of two kinds of materials. The vertical axis represents a value obtained by dividing the load when a load of 2 mm is applied by applying a load to the center of a simple support beam having a span of 6 mm by the sectional area at that time. The horizontal axis shows the composition ratio (L: P) of hard nylon L and soft nylon P. The figure shows the stiffness at each composition ratio in the transition region between the point A composed entirely of hard nylon L and the point B composed entirely of soft nylon P. Graph a of symbol は is an unmixed tube with a hard outer layer and a soft inner layer, graph b of symbol ■ is an unmixed tube with a soft outer layer and a hard inner layer, graph c of symbol △
Denotes a tube in which both materials are melted and kneaded, and a graph d indicated by a symbol x denotes a tube formed by mixing both materials in a pellet state. As shown in the drawing, in the case of the tube of the graph c which is melt-kneaded, the rigidity is low and changes very slowly at a position close to 100% soft nylon (point B), and the soft nylon portion moves to the soft nylon portion. 100% hard nylon (point A)
Has been migrated to. That is, the rigidity is changed on the side closer to the hard member without a sudden change in the rigidity of the soft material. For this reason, the strength reliability against bending of the tube is enhanced.

FIG. 13 shows the breaking strength of the same material as in FIG. As shown in the figure, the four types of tubes (graphs a, b, c, and d) change with almost the same strength (the melt-kneaded tubes in graph c tend to have a somewhat higher strength). That is, the melt-kneaded tube can obtain a preferable profile of change in rigidity as shown in FIG. 12 described above while maintaining sufficient strength.

[0039]

As described above, in the present invention, for example, at the boundary between the hard first resin and the soft second resin,
While the composition ratio of both resins in the ring-shaped cross section changes so as to gradually increase or decrease with respect to one resin,
Since the two resins are kneaded at the boundary, a rapid change in rigidity at the interface is suppressed, and the reliability of bonding is improved.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view of the entire catheter tube manufacturing apparatus according to the present invention.

FIG. 2 is a configuration diagram of an example of a catheter using the tube of the present invention.

FIG. 3 is a structural explanatory view of a material transition portion of the catheter tube according to the present invention.

FIG. 4 is a cross-sectional view of a material transition portion of the catheter tube according to the present invention.

FIG. 5 is a shape explanatory view showing an example of a mandrel of the catheter front tube manufacturing apparatus according to the present invention.

FIG. 6 is an explanatory view showing the shape of another example of the mandrel of the catheter tube manufacturing apparatus according to the present invention.

FIG. 7 is a shape explanatory view showing another example of the mandrel of the catheter tube manufacturing apparatus according to the present invention.

FIG. 8 is a shape explanatory view showing another example of the mandrel of the catheter tube manufacturing apparatus according to the present invention.

FIG. 9 is a shape explanatory view showing another example of the mandrel of the catheter tube manufacturing apparatus according to the present invention.

FIG. 10 is a shape explanatory view showing another example of the mandrel of the catheter tube manufacturing apparatus according to the present invention.

FIG. 11 is a shape explanatory view showing another example of the mandrel of the catheter tube manufacturing apparatus according to the present invention.

FIG. 12 is a graph showing the bending stiffness of a catheter tube made of two materials.

13 is a graph showing the breaking strength of the catheter tube shown in FIG.

FIG. 14 is a configuration diagram of an extrusion die portion of a conventional catheter tube manufacturing apparatus.

FIG. 15 is a cross-sectional view of a joint boundary.

[Explanation of symbols]

1: core wire feeder, 2: extrusion die, 3: A extruder, 4: B
Extruder, 5: cooling water tank, 6: take-up machine, 7: take-up machine, 8:
Catheter, 9: hub, 10: strain relief, 1
1: catheter tube, 11a: proximal portion, 11
b: tip, 11c: transition, 12: catheter tube, 12a: hard, 12b: soft, 12c: transition, 12d: boundary layer kneading, 13: mandrel, 14:
Shaft, 15: resin supply cavity of inner layer, 16: resin supply cavity of outer layer, 17: die, 18: resin passage, 19: concave portion, 20: enlarged channel, 21: extrusion hole, 2
2: Channel reduction part, 23: annular convex part, 24: groove, 25:
Double thread screw, 26: step, 30: extrusion die, 31: extrusion hole, 32: die, 33: bolt, 34: die holder,
35: Mandrel, 36: Inner layer mandrel holder, 3
7: outer layer mandrel holder, 38: guide cavity, 39: switching device, 40: switching device, 41: switching valve,
42: A resin inlet, 43: A resin supply port, 44: communication path, 46: communication path, 47: heater, 48: shaft, 5
0: tube, 51: B resin, 52: A resin.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takeshi Kizuka 3898-1 Asaba-cho, Asaba-cho, Iwata-gun, Shizuoka Prefecture Zima Corporation (72) Inventor Satoru 3898-1 Asaba-cho, Asaba-cho, Iwata-gun, Shizuoka Prefecture Zima Corporation F Term (reference) 4F207 AA00 AG08 AH63 KA01 KA17 KL62 KL88

Claims (4)

[Claims] 1. A catheter tube formed of a first resin and a second resin having different hardnesses continuous in a longitudinal direction, wherein a transition portion between the first resin and the second resin has a rigidity in a longitudinal direction. The composition ratio of the first resin and the second resin in the cross section changes along the longitudinal direction so as to gradually increase or decrease along the longitudinal direction, and at the interface between the first resin and the second resin, A catheter tube, wherein a kneading region is formed. 2. An extruder having a die having an extrusion hole, a die holder for holding the die, and a mandrel mounted in the die holder and engaging with the extrusion hole. A method for manufacturing a catheter tube formed of a first resin and a second resin having different hardnesses continuously, wherein the first resin is added to the extrusion mold while changing a flow path area for the resin passing through the extrusion hole. And supplying the second resin alternately. 3. A catheter tube having a die having an extrusion hole, a die holder for holding the die, and a mandrel mounted in the die holder and having a mandrel engaged with the extrusion hole. An apparatus for manufacturing a catheter tube, wherein a resin kneading means is provided between a die and a mandrel at an entrance of the extrusion hole. 4. The apparatus according to claim 3, wherein said resin kneading means comprises a convex portion, a concave portion or a step portion formed on said die and / or mandrel.