JPH01297071A - Production of balloon catheter - Google Patents

Abstract

PURPOSE:To facilitate the control of an expansion rate and to improve quality by forming only the balloon having the composite structure in which a woven material is used as a reinforcing material and attaching the balloon to a catheter in the same manner as an ordinary balloon catheter and fixing the same. CONSTITUTION:This catheter is formed of the composite of the 2-layered structure obtd. by impregnating and integrating a rubber-like elastic material 2 into and to the cylindrical woven material 1 formed around a die bar 9 and vulcanizing the rubber-like elastic material 2. The catheter is otherwise formed of the composite of the 3-layered structure obtd. by impregnating and integrating the rubber-like elastic material 6 into and to the cylindrical woven material 5 formed around the die bar 9 provided with a layer 4 of a cylindrical elastic material on the surface, then vulcanizing the rubber-like elastic materials 4, 6. The balloon 10 having the composite structure obtd. by this method is put on the catheter tube 8 and both ends thereof are adhered by an adhesive agent or are tied by yarn 11 or are fixed by both thereof.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to dilation and patency of narrowed portions of body lumens such as the esophagus, blood vessels, valves, bile ducts, urethra, and ureters, and removal of foreign bodies such as thrombi. The present invention relates to a method for manufacturing a medical balloon catheter for use in the medical field.

[Conventional technology]

In order to gradually dilate a narrowed part of a biological lumen, it is necessary to prevent pressure from being applied locally due to deformation of the balloon, and also to prevent it from expanding beyond a certain limit. Rather than using an elastic body, pre-molded balloons made of resin, which do not expand or contract themselves, are used and are highly valued.

However, these molded resin balloons have many drawbacks in use and manufacturing, so in order to solve these problems, we have developed a combination of braided material and elastic material to increase the strength of the balloon. , balloons that are not inflated beyond a certain limit have been proposed.

For example, in Japanese Patent Application Laid-Open No. 59-91970, kM&I
Using a tube made of I material, the outside of the part that will become the shaft of the catheter is coated with an inelastic coating made of semi-hard material, and the inside of the part that will become the shaft and the inside and outside of the part that will be the balloon are covered with elastic coatings. A dilatation catheter is disclosed. However, this catheter is reinforced with a braided material over almost its entire length, and the covering material is different between the outside and inside, or between the shaft and the balloon, or only the part that becomes the balloon is made of KIA&ll material. There is a problem that the manufacturing process becomes extremely complicated because methods such as roughening are used. Another drawback is that it is difficult to control the inflation diameter and length of the balloon.

Furthermore, in Japanese Patent Publication No. 103453/1983, the balloon structure has an inner layer and an outer layer made of elastic polyurethane, and an intermediate layer made of &i tubes, and even though the polyurethane itself is said to be elastic, it is made of rubber. Balloons have been proposed that have significantly lower elasticity compared to the quality, and are reinforced by combining them with &W tubes without losing elasticity, but there are restrictions on the inflation rate and it is difficult to control. Above, when forming a balloon, the inner layer and middle layer are fixed to a sleeve attached to the catheter and immersed in liquid polyurethane to form the outer layer, which poses many manufacturing problems, such as difficulty in selecting the inflation rate, etc. Not only is it difficult to handle as it requires a very large amount of force to inflate, but it is also difficult to control manufacturing conditions, which can easily cause problems with quality. If the adjustment fails, there is a problem in that there is a large loss in manufacturing costs including catheter components and assembly man-hours.

(Problems to be Solved by the Invention) In view of the problems of conventional balloon catheters for dilating and opening constricted areas in biological lumens, the present invention aims to control the inflation rate and manufacturing conditions of the balloon. The object of the present invention is to provide an economically advantageous method for manufacturing a balloon catheter that is easy to manufacture, has excellent reproducibility and quality stability, and has a simple manufacturing and assembly process, making it suitable for mass production.

[Means to solve the problem]

That is, the present invention is directed to knitting a cylindrical knitted fabric around a mold rod having the same outer diameter as a catheter tube using a circular knitting machine, or a cylindrical knitted fabric knitted using a circular knitting machine or a flat threading machine. is placed around a mold rod having the same outer diameter as the catheter tube, immersed in natural rubber latex, synthetic rubber latex, or silicone rubber solution to impregnate the rubber, and air-dried until dry to the touch. A balloon characterized in that, after repeating the operation multiple times, the rubber is vulcanized by raising the temperature, the resulting composite is placed over a catheter tube, and both ends are tied with thread and/or fixed with adhesive. This is a method for manufacturing a catheter.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing the structure of a balloon according to an embodiment of the present invention. Its basic structure consists of a cylindrical knitted fabric (1) formed around a mold rod (9) and a rubber-like elastic material ( It is a composite with a 2N structure obtained by impregnating and integrating the rubber-like elastic material (2) and then vulcanizing the rubber-like elastic material (2).

FIG. 2 shows the structure of a balloon according to another embodiment of the present invention, the basic structure of which is formed around a mold rod (9) having a cylindrical elastic material layer (4) on its surface. A three-layer structure obtained by impregnating the formed cylindrical knitted fabric (5) with a rubber-like elastic substance (6) and then vulcanizing the rubber-like elastic substances (4) and (6). It is a complex of

Classifying this from the viewpoint of manufacturing method, it can be roughly divided into the following four methods.

i) Use a circular knitting machine to create a cylindrical knitted fabric (1
1 is knitted, immersed in a rubber liquid to impregnate it, dried and vulcanized to obtain a two-layered composite balloon (3).

ii) Using a mold rod (9) that has been immersed in a rubber liquid and dried to form a rubber film (layer of elastic material) (4) on its surface in advance,
A three-layered composite balloon (7) is obtained by the method i).

iii) A cylindrical knitted fabric (1) previously knitted using a circular knitting machine or a flat knitting machine is placed around the mold rod (9), dipped in a rubber solution to impregnate it, dried and vulcanized. 27
An i-structured composite balloon (3) is obtained.

iv) Using the mold rod (9) on which a rubber film (layer of elastic material) (4) has been formed in advance by immersing it in a rubber liquid and drying it, a three-layer composite balloon is prepared using the method of iii). (7
).

As mentioned above, the basic structure of balloons can be roughly divided into two-layered balloons (3) and three-layered balloons (7), and the manufacturing method is to knit a cylindrical knitted fabric +11 directly around the mold rod (9). Method of impregnating elastic substances (2) and (6) and mold rod (9)
) is covered with a separately knitted cylindrical knitted fabric (5) and impregnated with elastic substances (2) and (6).

A balloon with a composite structure obtained by these methods can be obtained by covering the catheter tube (8) with a balloon α field and gluing both ends with adhesive or tying it with thread 00, as shown in Fig. 3. , fixed with both. Furthermore, coating the joint with resin will ensure complete safety, and this method is especially recommended as a fixing method for balloons that require pressure resistance.

Adhesives include latex rubber, silicone rubber,
Epoxy resin, polyurethane, etc. can be used. Further, although fixing with the thread αD may be used depending on the purpose, there is no problem in fixing with a tape-like material.

Next, factors that determine the expansion rate, which is an important characteristic of a balloon with a composite structure, include the type and characteristics of the rubber-like elastic material and the cylindrical knitted material. As the rubber-like elastic material, natural rubber latex, synthetic rubber latex, silicone rubber solution, etc. are used, and the expansion rate of the balloon is greatly influenced by the elastic modulus of the material. Thermoplastic elastomers can also be used to make them relatively difficult to stretch. In addition, the operation of soaking the balloon in a rubber liquid to impregnate it with rubber and air drying it until it is dry to the touch should be repeated several times, preferably 2 to 6 times, to prevent the formation of pinholes in the resulting balloon. It can be completely prevented.

On the other hand, the characteristics of a cylindrical knitted fabric are determined by the type of fiber material (yarn) used, the knitting method, the stitch density, etc., and by appropriately selecting and combining these, the desired expansion rate can be obtained. Specifically, ■ change the type of thread. for example,
For balloons that require a small diameter and high strength, use polyester fibers or polyamide fibers, etc. whose threads themselves have low elongation, and for balloons that have a large diameter and require a high expansion ratio, use materials with an elongation of 100 to 800%. Spandex fibers are suitable. For intermediate uses, elongation is 20 to 5.
Although 0% woolly nylon is used, a combination of different types of yarn may be used.

(2) Changing the Thickness of Thread Normally, threads of 50 to 200 deniers are used, but by using thicker threads of up to about 300 deniers, the knitted fabric material can be made more difficult to stretch.

■ Changing the knitting method 0 Normally, flat knitting or rubber knitting is used among weft stockinette knitting, but if you want it to be difficult to stretch, tank knitting, floating knitting, etc., which are somewhat difficult to stretch, are used.

■ Change the stitch density 0 Normally, the number of wales (vertical row 1
Number of stitches per inch) 40 to 65, number of courses (horizontal row 1
The number of stitches per inch is in the range of 50 to 75, but by increasing the number of wales and courses by 20 to 30 each, it becomes difficult to elongate, and by decreasing them, elongation can be increased. In addition, although it is usually knitted with one thread, it is also possible to knit with one thread of the same thickness or different thickness.
A method of knitting two strands in addition to one is also effective.

〔Effect of the invention〕

The balloon in the present invention has a composite structure using knitted material as a reinforcing material, but first, only the balloon is made,
Since it is attached and fixed to the catheter tube in the same way as a normal balloon catheter, it is easy to control the expansion rate and manufacturing conditions of the balloon, and it is possible to obtain a balloon of stable quality. Not only is the (assembly) process simple and suitable for mass production, but it also has the advantage that the existing balloon catheter assembly process can be used almost as is, making it suitable as a method for manufacturing medical balloon catheters using composite structure balloons. .

[Brief explanation of the drawing]

FIGS. 1 and 2 are schematic diagrams showing the basic configuration for manufacturing a balloon with a composite structure used in the present invention. FIG. 1 shows a balloon with a two-layer structure, and FIG. 2 shows a balloon with a three-layer structure. Moreover, FIG. 3 is a schematic diagram showing an example of a state in which a balloon is attached to a catheter tube.

Claims (4)

[Claims] (1) A circular knitting machine is used to knit a cylindrical knitted fabric by flat knitting, rubber knitting, floating knitting, or tuck knitting around a mold rod having an outer diameter dimension equivalent to that of the catheter tube, and this is made of natural rubber latex, After repeating the process of dipping into a synthetic rubber latex or silicone rubber solution to impregnate the rubber and air-drying it until it is dry to the touch, the temperature is raised to vulcanize the rubber, and the resulting composite is inserted into a catheter. A method for manufacturing a balloon catheter, which comprises placing the catheter over a tube, tying both ends of the catheter with a thread, and/or fixing the catheter with an adhesive. (2) In the balloon catheter manufacturing method according to claim (1), the mold rod is dipped in advance in a natural rubber latex, synthetic rubber latex, or silicone rubber solution and dried to form a rubber film on the surface of the mold rod. After that, the cylindrical knitted fabric is knitted, and a rubber membrane is further formed in this state. (3) Using a circular knitting machine or a flat knitting machine, flat knitting, rubber knitting,
A cylindrical knitted fabric is knitted by floating knitting or tuck knitting,
It is placed around a mold rod having the same outer diameter as the catheter tube, and immersed in natural rubber latex, synthetic rubber latex, or silicone rubber solution to impregnate the rubber.
After repeating the air-drying process several times until it is dry to the touch, the temperature is raised to vulcanize the rubber, the resulting composite is placed over the catheter tube, and both ends are tied with thread and/or fixed with adhesive. A method for manufacturing a balloon catheter, characterized by: (4) In the method for manufacturing a balloon catheter according to claim (3), the mold rod is dipped in advance in a natural rubber latex, synthetic rubber latex, or silicone rubber solution and dried to form a rubber film on the surface of the mold rod. A method for manufacturing a balloon catheter, which comprises covering the catheter with a cylindrical knitted fabric and further forming a rubber film in this state.