JP2001299926A - Stepped catheter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stepped catheter improved in the mountability onto a hub and having proper elongation and sufficient strength. SOLUTION: This stepped catheter (catheter tube 4) comprises a major diameter part 4a constituting the hub or the mounting part onto the hub and a minor diameter part 4b formed continuously by use of a material integrated to the major diameter part 4a. The elongation of the material of the minor diameter part 4b is smaller than that of the major diameter part 4a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stepped catheter having improved attachment to a hub.

[0002]

2. Description of the Related Art A medical catheter is used by attaching a catheter tube made of a resin elastomer or the like to a hub having an insertion port for a guide wire, a contrast agent or the like. The hub of such a catheter has a substantially constant size for connection to a drug solution injector or the like, and various kinds of catheter tubes having different diameters according to the purpose of use and the like are attached to the hub.

[0003] Such catheter tubes are often thin, having an outer diameter of 1 mm or less, and in particular, micro-catheters for children have an outer diameter of about 0.5 mm or less. In some cases, it is difficult to mount the device on the device, and there is a case where a problem occurs in terms of time and labor and reliability of the mounting and joining. Further, in a multi-lumen catheter in which a plurality of tubes such as two lumens and three lumens are attached to one hub, it is more difficult to join the catheter to the hub.

[0004] Therefore, in the hub mounting portion of the small diameter tube,
A stepped catheter in which a large-diameter tube is joined to facilitate handling and is attached to a hub has been considered.

On the other hand, in the case of an indwelling needle for indwelling a drug or the like in a body, a large-diameter hub portion and a small-diameter tube portion are formed of an integral resin to improve the reliability of joining and assembling, thereby improving the manufacturing process. Some have been developed with a simplified structure.
In such an indwelling needle structure made of an integral resin, for example, a large-diameter tube is heated and stretched by hot stretching to form a small-diameter tube.

[0006] In such a catheter (including an indwelling needle), the catheter tube to be inserted into the body has sufficient strength, flexibility and elasticity, and accordingly a certain degree of extensibility is required. It is.

Conventionally, to increase the strength of a catheter,
A reinforcing blade layer made of resin or metal is provided between the inner and outer layers of the catheter tube having a two-layer structure of an inner layer and an outer layer, or a surface treatment for reinforcement is performed.

[0008]

However, when the diameter of the catheter is reduced as described above, it becomes technically very difficult to provide a blade layer for increasing the strength or to perform surface treatment.

With respect to the flexibility, sufficient flexibility due to the elasticity of the elastomer material is necessary. However, if the elongation percentage when the catheter tube is pulled is too large, the catheter tube may be slightly caught when pulled out. As a result, the tube may be stretched and stagnated, which may hinder a smooth drawing operation. Therefore, it is desirable that the elongation ratio is small.

Further, in the conventional stepped catheter for improving the assemblability of the catheter tube and the hub, the large-diameter portion and the small-diameter portion are separately formed and joined to each other. There is a possibility that the strength may decrease or peeling may occur.

Further, if the conventional indwelling needle structure in which the hub and tube are formed of an integral resin is simply diverted to a stepped catheter having a small diameter, a catheter tube having an appropriate elongation and strength cannot be obtained.

The present invention has been made in consideration of the above-mentioned prior art, and has as its object to provide a stepped catheter having an improved extensibility to a hub, an appropriate extensibility, and a sufficient strength.

[0013]

In order to achieve the above object, according to the present invention, there is provided a large diameter portion constituting a hub or a portion to be attached to the hub, and a small diameter portion formed integrally with the large diameter portion. A stepped catheter comprising: a stepped catheter, wherein the elongation of the material of the small diameter portion is smaller than the elongation of the large diameter portion.

According to this configuration, since the large diameter portion of the hub mounting portion and the small diameter portion of the catheter tube are formed of an integral material, the workability of mounting to the hub is improved, and the possibility of separation or breakage is eliminated, and reliability is improved. As a result, a small diameter portion that is inserted into the body at the time of use has a small extension, so when pulling out the catheter, the catheter tube can be extended smoothly due to slight hooking, etc. Usability is improved.

In a preferred embodiment, the breaking strength of the material of the small diameter portion is larger than the breaking strength of the large diameter portion.

According to this configuration, since the breaking strength of the small diameter portion serving as the catheter tube is increased, a catheter having high reliability in strength can be obtained.

In a further preferred configuration example, the elongation percentage of the material of the small diameter portion is about 200% or more and 600% or less when a 0.33 mmφ tube is used, and the breaking strength is 3%.
It is characterized in that it is not less than 00 g and not more than 500 g.

Such a range is determined experimentally. Regarding the elongation, if it is more than this range, the catheter tube is too elongated to be able to be pulled out smoothly, and if it is less than this range, the rigidity is too strong to use. Worse. With respect to the breaking strength, if it is within this range, the strength can be increased as compared with a conventional catheter tube, and it can be realized by using a normal elastomer.

According to the present invention, a method for manufacturing a stepped catheter in which such a large diameter portion and a small diameter portion having different elongation rates and breaking strengths are formed integrally from the same material,
The original tube is set in a stretching device capable of heating and stretching, the original tube is heated, the heated portion is subjected to primary stretching by hot stretching, and after this primary stretching, secondary stretching is performed at room temperature. A method for manufacturing a stepped catheter, wherein the small diameter portion is formed by a portion, and the large diameter portion is formed by a raw tube tube of a non-heated, non-stretched portion adjacent to the small diameter portion.

According to this configuration, the original tube is once stretched as the primary stretching in the hot stretching in which the heated portion is stretched, cooled by natural cooling or the like, and then subjected to the secondary stretching by the cold stretching at room temperature without heating. The tube is stretched to form a small diameter portion of the tube. A sharp step is formed between the stretched small diameter portion and the unheated and unstretched original tube tube that is not stretched, and the large diameter portion of the sharply constricted step portion has a large diameter portion. Form.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram of a catheter according to the present invention, and FIG. 2 is an outline view of the catheter tube.

This catheter 1 has a hub 2 having an insertion port 2a for a drug solution injector, a guide wire or the like mounted on a catheter tube 4 of the present invention. As shown in FIG. 2, the catheter tube 4 is composed of a large-diameter portion 4a serving as an attachment portion to the hub and a small-diameter portion 4b formed of an integral material continuously from the large-diameter portion 4a. It has the shape of a stepped tube with a distinct step 3 formed between them. The stepped catheter tube 4 is made of, for example, a polyester elastomer, and as described later, the catheter tube 4 of the present invention.
It is formed by stepwise stretching. By this two-step stretching process, the elongation characteristics of the small-diameter portion 4b are made smaller than the elongation characteristics of the large-diameter portion 4a, and the breaking strength of the small-diameter portion 4b is reduced from that of the large-diameter portion 4a. Can be larger.

FIG. 3 is a flowchart of a method for manufacturing a stepped catheter tube according to the present invention. First, a raw tube (not shown) of a catheter made of an elastomer of polyester or other resin material is set in a heating and stretching device (not shown) having a heater and a pulling means (step S1). The diameter and length of the original tube correspond to the diameter and length of the target catheter tube obtained after stretching. Both ends of such a raw tube are clamped by a suitable chuck mechanism.

Next, a portion of the original tube to be extended is heated by the heater (step S2). At this time, the heater temperature is, for example, about 240 to 250 ° C., and the raw tube is heated to near the melting temperature (about 200 ° C. for polyester elastomer) by radiant heat transfer.

A primary stretching process by hot stretching is performed by pulling and stretching both ends of the heated and softened raw tube tube (step S3). At this time, the heater may be removed. By this hot stretching, the original tube is stretched to, for example, three times the length. As a result, a clear step is formed between the stretched and thinned portion and the unheated, unstretched raw tube. The primary stretching process is completed by performing such hot stretching (step S4).

Next, the temperature of the primary hot stretched portion stretched three times is lowered by natural cooling for, for example, about 30 seconds (step S5), and a secondary stretching process is performed by cold stretching at room temperature (step S5). Step S6). Thereby, depending on the required length, it is 2 to 5 times (6 to 5 times for the original tube).
(15 times). The secondary stretching process is completed by performing such cold stretching (step S7).

Thereafter, the tube stretched by the two-stage stretching process is taken out (step S8), and one large diameter portion is cut off to form the catheter tube 4 as shown in FIG.

FIG. 4 is a graph of the experimental data of the elongation rate of the stepped catheter tube formed by the two-step stretching process, and FIG. 5 is a graph of the experimental data of the breaking strength. In FIG. 4, the vertical axis shows the elongation (%), and in FIG. 5, the vertical axis shows the breaking strength (gram weight g: 1 g ≒ 0.0098 N).

In the graphs of FIG. 4 and FIG.
Is the average value of the measurement results of the original tube having an outer diameter of 0.33 mmφ, and point B is the measurement result of the tube obtained by stretching the original tube three times by hot stretching (primary stretching). It is the average value of the values converted to a 0.33 mmφ tube. At points C, D, E and F, the tube stretched three times by hot stretching was further stretched two, three, four and five times by cold stretching (secondary stretching). It is the average of the values obtained by converting the measurement results of the tubes into tubes having an outer diameter of 0.33 mmφ.

As shown at points C to F in FIG. 4, the elongation is reduced by performing the secondary cold stretching after the primary hot stretching, as compared with the case of only hot stretching (point B). 200-6
It was within the range of 00%. Further, as shown at points C to F in FIG. 5, by performing the secondary cold stretching after the primary hot stretching, the breaking strength is increased as compared with the case of only hot stretching (point B), and almost 300 to It was within the range of 500 g.

[0031]

As described above, according to the present invention, since the large diameter portion of the hub mounting portion and the small diameter portion of the catheter tube are formed of an integral material, the workability of mounting to the hub is increased by the large diameter hub mounting portion. Improved, integral formation with the small diameter portion eliminates the risk of separation or breakage, etc., and a highly reliable catheter is obtained, and the small diameter portion inserted into the body during use is small in extension, so when pulling out the catheter, The catheter tube can be pulled out smoothly without stagnation due to stretching of the catheter tube due to slight hooking or the like, and usability is improved. Further, since the breaking strength of the small-diameter portion serving as the catheter tube increases, a catheter having high strength and reliability can be obtained. In particular, a remarkable effect can be obtained by applying the present invention to a small-diameter catheter such as a pediatric catheter or a multi-lumen catheter such as a 2-lumen or 3-lumen catheter.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a catheter according to the present invention.

FIG. 2 is an external view of a catheter tube.

FIG. 3 is a flowchart of a method for manufacturing a stepped catheter tube according to the present invention.

FIG. 4 is a graph of experimental data of elongation of a stepped catheter tube formed by a two-step stretching process.

FIG. 5 is a graph of experimental data on the breaking strength of a stepped catheter tube formed by a two-step stretching process.

[Explanation of symbols]

1: catheter, 2: insertion port, 3: step portion, 4: catheter tube, 4a: large diameter portion, 4b: small diameter portion

Claims (4)

[Claims] 1. A stepped catheter comprising a hub or a large-diameter portion forming an attachment portion to a hub, and a small-diameter portion formed continuously with the large-diameter portion, wherein a material of the small-diameter portion is formed. A stepped catheter, wherein the elongation is smaller than the elongation of the large diameter portion. 2. The stepped catheter according to claim 1, wherein the breaking strength of the material of the small diameter portion is larger than the breaking strength of the large diameter portion. 3. The elongation rate of the material of the small diameter portion is 0.33 m.
The stepped catheter according to claim 2, wherein when the tube has a diameter of mφ, it is about 200% or more and 600% or less, and the breaking strength is 300 g or more and 500 g or less. 4. The original tube is set in a stretching device capable of heating and pulling, the original tube is heated, the heated portion is subjected to primary stretching by hot stretching, and after this primary stretching, is subjected to secondary stretching at room temperature. The small-diameter portion is formed by the secondary stretched portion, and the large-diameter portion is formed by a raw tube tube of a non-heated non-stretched portion adjacent to the small-diameter portion. A method for producing the stepped catheter according to the above.