JPH088931B2 - Manufacturing method of vascular catheter - Google Patents

Description

TECHNICAL FIELD The present invention relates to a vascular catheter. For more information,
The present invention relates to a method of manufacturing a blood vessel catheter having a tube tip portion that does not require tapering or bending of the tube tip portion and that does not change its shape economically and has a strong restoring force.

[Conventional technology]

Traditionally, vascular catheters have been used in blood vessels of the heart, abdominal arteries,
It is used when inserting a contrast medium into a coronary artery or a blood vessel of the head, or when performing treatment such as enlarging a stenosis. A blood vessel catheter is generally a tube body made of a synthetic resin inner tube made of a synthetic resin such as polyethylene, a wire mesh attached (braided) to the outer circumference of the inner tube, and an outer tube coated on the wire mesh, It is composed of a hollow synthetic resin tube distal end formed at one end of the tube body. The tube tip is tapered so that it can be smoothly moved in the blood vessel, and is appropriately bent according to the bending condition of the blood vessel and the shape of the organ. Such a blood vessel catheter can be moved in a blood vessel with a guide wire inserted in the inner tube. Then, when the guide wire is pulled out after the tube tip reaches the vicinity of the target organ, the tube tip returns to its original bent state, and the tip of the tube can be positioned at a predetermined place in the organ. .

Under the present circumstances, such vascular catheters are mainly manufactured by the following two types of methods.

First, in the first method, an inner tube made of a thermoplastic resin is extruded and a wire mesh made of stainless steel or the like is knitted on the outer circumference of the obtained inner tube. Then, the stitches are cut at regular intervals so that the portions with the stitches and the portions without the stitches appear alternately (see FIG. 5). After that, the cut surface of the wire mesh is fixed so as not to be fluffed, and the inner tube is covered and extruded to form an outer tube made of synthetic resin on the outer periphery of the inner tube. After forming the outer tube, the tube body was cut into a length of one catheter (in Fig. 5, the length of one catheter is represented by (1)), and this tube was immersed in a polyethylene glycol solution at about 160 ° C. Then, the tip portion (see (11) in FIG. 5) is subjected to a stretching treatment by heating and the tip portion of the tube tip portion (tapering and bending) is performed. Finally, the chamfering of the tip of the tube is performed. The bending of the tube tip may be performed while heating the tube tip with, for example, hot air, hot water, or the polyethylene glycol solution (liquid 160 ° C.) described above.

On the other hand, as the second method, there is one described in US Pat. No. 3,485,234. In the method described in this specification, the wire mesh is knitted on the extruded inner tube in the same manner as the first method. After the outer tube is formed on the inner tube by coating and extruding, the obtained tube body is cut into a length of one catheter, and only the outer tube at one end is peeled off by a predetermined length. after that,
The separately-prepared tapered distal end of the tube having the larger inner diameter is spread out, and the stripped portion of the outer tube is inserted into this portion. Finally, a sleeve made of a heat-shrinkable material is fitted to the connection portion and heated to connect the tube tip portion and the tube body. The sleeve is removed after the connection is complete. The bending of the tube tip portion is performed by bending the tube tip portion while heating the tube tip portion as in the first method.

[Problems to be Solved by the Invention]

However, in the first method of the above-mentioned two methods, the tapering of the tube tip is performed by the stretching treatment under heating, and even if the temperature conditions and the pulling speed are controlled, the taper degree and the tube meat are reduced. There is a problem that the dimensions such as thickness are inevitably varied, and because the bending of the tube tip is done by heating, the bent state cannot be maintained for a long time and it will inevitably deform over time. In addition, since the bent part formed under heating is so-called weak, the guide wire is forcibly straightened for insertion into the blood vessel, and the guide wire is pulled out at the intended location. Even if you try to return it to the bent state, it does not return to the original shape accurately, and the tube tip is placed in the specified position. There is a problem that can not be.

On the other hand, regarding the second method, since there is no description as to how the tapering of the tube tip portion is performed, the dimensional accuracy of the tube tip portion is unknown, but the tube tip portion is bent. Is insufficient and the shape changes with time and the stiffness is weak, and there are the same problems as in the first method.

Furthermore, as can be said in common with all methods, in order to obtain a vascular catheter, it takes a laborious process of tapering and bending the tube tip, which means that It took time to manufacture and was a cause of cost increase.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for producing a blood vessel catheter in which the drawbacks of the above-mentioned conventional techniques are eliminated. That is, an object of the present invention is to provide a method of manufacturing a blood vessel catheter which can omit tapering and bending, can prevent shape change over time, and can significantly improve dimensional accuracy. Is.

[Means for solving the problem]

The method for producing a blood vessel catheter of the present invention includes a tubular main body made of a synthetic resin inner tube, a wire mesh attached to the outer periphery of the inner tube, and a synthetic resin outer tube coated on the wire mesh, A method for manufacturing an angiocatheter having a tapered hollow tube tip portion at one end of a tube body, comprising a step of knitting a wire mesh on the outer circumference of an inner tube, and an outer tube on the outer circumference of the inner tube with the wire mesh. The step of covering and forming the tube body, the step of cutting the obtained tube body to a specified length, the step of peeling the outer tube at one end of the tube body after cutting for a specified length, and the outer tube Step of inserting the inner pin from the stripped side into the inner tube A step of arranging the tube main body with the inner pin inserted therein in one mold of a splitting machined so as to correspond to the outer shape of the tube tip, and aligning the other mold of the split mold with the one mold, And a step of pouring a synthetic resin forming the tip portion of the tube into the mold.

〔Example〕

Next, a method for producing the blood vessel catheter of the present invention will be described with reference to the drawings.

First, a wire mesh (2) made of stainless steel or the like is provided on the outer circumference of a tubular synthetic resin inner tube (1) (see FIG. 1) obtained by an ordinary extrusion molding method or the like.
Is woven. The wire diameter is not particularly limited in the present invention, but a wire diameter of about 0.02 to 0.5 mm is preferably used. This wire is braided on the inner tube (1) by a braiding machine for taking 8 to 24 pieces. The material of the inner tube (1) may be selected in consideration of workability, flexibility, biocompatibility, chemical resistance, etc., and, for example, polyethylene,
Polyurethane, olefin elastomer and the like can be preferably used.

Next, the outer tube (3) is covered and molded on the outer circumference of the inner tube (1) in which the wire mesh (2) is woven by a covering molding extruder or the like, and the tube body (A) is formed. The material of the outer tube (3) is the same as that of the inner tube (1) described above.

The obtained tube body (A) is cut into a length of one catheter. After cutting the tube, the outer tube (3) at one end of the tube body (A) is peeled off by a predetermined length using a cutter or the like. The portion where the outer tube is stripped off is a portion formed by overlapping a tube tip portion (4) described later on the outer periphery thereof, and the length (a) (see FIG. 1) of the tube main body (see FIG. 1). It may be selected in consideration of the strength of the connection between A) and the tip of the tube and the shape of the tip (insertion site), and is not particularly limited in the present invention, but is generally about 20 to 60 mm.

Then, the inner pin (5) is inserted into the inner tube (1) from the stripped side of the outer tube. The inner pin (5) is used to secure the hole of the hollow tube distal end (4) formed by the subsequent insert molding method.

The tube body (A) into which the inner pin (5) is inserted is placed in one of the split molds (6a) which is processed to correspond to the outer shape of the tube tip (4). After the arrangement, the other mold (6b) of the split mold is fitted to the one mold (see FIG. 2).

After arranging the split mold, configure the tip of the in-mold tube,
For example, a synthetic resin such as polyethylene or polyurethane is poured from an appropriate place. It should be noted that if the same material as the inner tube and the outer tube is used as the material of the tube distal end portion, it is easy to weld, so that a strong connection portion can be obtained. The split mold is disassembled after the poured synthetic resin is cooled for a predetermined time by utilizing an appropriate cooling means provided in the split mold.

The split molds (6a) and (6b) shown in FIG. 2 are processed so as to form a straight tube tip, but the split molds (16a) shown in FIG. ) (Only one is shown) can be used to form a curved tube tip. Thus, in the present invention,
Since the tip of the tube is insert-molded using the mold, there is an advantage that the tube tip (4) can be formed, tapering and bending can be performed at the same time. Then, not only the bending process can be omitted, but since the poured synthetic resin solidifies in a bent state, the waist becomes very strong, and the shape may change with time like the above-mentioned conventional technology. However, since the restoring force is strong even if it is deformed, it can easily return to its original shape.

In the above description, only the outer tube was peeled off before forming the tube tip, but as shown in FIG. 4, a part of the wire mesh may be cut off together with the outer tube. In this way, the length of the overlapping portion of the tube ends is made longer, so that the strength of the connecting portion can be further improved.

〔The invention's effect〕

As described above, according to the method for producing a blood vessel catheter of the present invention, the following effects can be achieved.

Since the tube tip is formed by insert molding using a mold, it is possible to omit the tapering step and bending of the tube tip, simplifying the entire manufacturing process, and in a short time and at low cost. A vascular catheter can be obtained.

Rather than imparting a bent shape by heating, the synthetic resin solidifies in a bent state in the mold, so the shape does not change over time, and a vascular catheter having a strong tube tip can be obtained. be able to.

Since the molding is performed by the mold, the dimensional accuracy of the tube tip can be significantly improved.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of a tube body in which an outer tube is stripped off, and FIG. 2 shows a state in which the tube body shown in FIG. 1 is arranged in a split mold used in the method for producing a blood vessel catheter of the present invention. Explanatory diagram showing, FIG. 3 is an explanatory diagram showing another example of the split mold used in the manufacturing method of the present invention, FIG. 4 is a schematic explanatory diagram of a tube main body in which a wire mesh is partially cut off together with an outer tube, FIG. 5 is a schematic explanatory diagram of a tube body in a conventional manufacturing method in which a wire mesh is stripped off at regular intervals. (Main symbols in the drawing) (A): Tube body (1): Inner tube (2): Wire mesh (3): Outer tube (4): Tube tip (5): Inner pins (6a), (6b) : Split type

Claims (2)

[Claims] 1. A tubular synthetic resin inner tube, a wire mesh attached to the outer periphery of the inner tube,
And a method for producing a blood vessel catheter having a tube body made of a synthetic resin outer tube coated on the wire mesh, and a hollow tube distal end formed to be tapered at one end of the tube body, comprising: A step of knitting a wire mesh on the outer periphery, a step of forming an outer tube on the outer periphery of the inner tube with the wire mesh to form a tube body, and cutting the obtained tube body to a predetermined length, The process of stripping the outer tube at one end of the tube body for a specified length, the step of inserting the inner pin into the inner tube from the side where the outer tube was stripped, and the tube body with the inner pin inserted Placing in one mold of a split mold processed to correspond to the outer shape of Combined other types of type to the type of the one, vascular catheters process, characterized by a step of pouring a synthetic resin of the tube tip in the mold. 2. The method according to claim 1, further comprising the step of cutting the wire mesh, which appears after the outer tube is stripped off, to a desired length.