JP2006129978A - Method for manufacturing catheter balloon - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for thinning a sleeve part of a catheter balloon. <P>SOLUTION: This method for manufacturing the catheter balloon by biaxial stretch blow molding of a parison carries out biaxial stretch blow molding of the balloon and thereafter, heats a balloon sleeve part with laser beams to stretch and thin it. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a balloon for a catheter, and more particularly, to expand and treat an intravascular stenosis in percutaneous luminal surgery including peripheral angioplasty, coronary angioplasty and valvuloplasty to improve peripheral blood flow. The present invention relates to a catheter balloon used in the above.

  Conventionally, when stenosis or occlusion occurs in a vessel such as a blood vessel, angioplasty (PTA: Percutaneous Transluminal) is performed to expand the stenosis or occlusion site of the vessel and improve blood flow on the peripheral side of the vessel. Angioplasty, PTCA (Percutaneous Transluminal Coronary Angioplasty, etc.) have a large number of surgical cases in many medical institutions, and have become common as a surgical operation in this type of case.

  Balloon catheters are used in a set of guide catheter and guide wire, mainly to dilate the stenotic site of the coronary artery. In this angioplasty using a balloon catheter, the guide catheter is first inserted from the femoral artery, the tip is positioned at the entrance of the coronary artery through the aorta, and then the guide wire penetrating the balloon catheter is narrowed in the coronary artery. Advance beyond the site, then advance the balloon catheter along the guidewire, inflate with the balloon positioned at the stenosis site and dilate the stenosis site, then deflate the balloon and remove it outside the body To do. However, balloon catheters are not limited to treating arterial stenosis but are useful for many medical applications including insertion into blood vessels as well as insertion into various body cavities.

  The balloon is usually manufactured by biaxially stretching blow molding a tube. The catheter balloon is composed of a straight tube portion having a relatively uniform thickness, a tapered portion that is inclined outwardly from both ends and having a small diameter, and a thin cylindrical sleeve portion that extends outward from both ends.

  When biaxial stretch blow molding is performed, it is inevitable that the tapered portion and the sleeve portion become thicker than the straight pipe portion.

  The balloon provided at the distal portion of the catheter shaft is required to have various characteristics due to its role of expanding the stenosis in the blood vessel. A high compressive strength is required to expand the calcified hard stenosis. In addition, high flexibility is required in order to locate the bent stenosis. In addition, in order to be positioned at a stenosis site having a very high stenosis degree of 99%, not only flexibility but also a sufficiently thin balloon is required. When these characteristics are combined, the balloon is required to be thin, to have high film strength, and to have high flexibility.

  When the cone and the joint are thick, the diameter of the balloon increases when the balloon is folded, and the flexibility of the balloon is impaired. Therefore, various methods have been proposed to make the tapered portion of the balloon and the tapered portion thinner.

  Patent Document 1 discloses a technique in which after forming a balloon, the sleeve portion or the taper portion is heated with hot air to be pulled and thinned. However, in this method, since the straight pipe portion that is not desired to be stretched is also heated, the straight pipe portion is also stretched to become thin, and the performance such as the breaking pressure and the dimensional stability is lowered.

In Patent Document 2, there is a method in which a parison having a thin portion corresponding to the sleeve portion is made and blown to make the sleeve portion thin. However, this method is difficult to form such a parison in advance, and it is difficult to bring the pre-thinned portion of the parison into the taper of the balloon and the sleeve during blow molding. .
JP-A-4-17463 As is apparent from the above example, the methods disclosed so far provide excellent properties for the balloon, but on the other hand cause other problems and are not perfect.

  An object of the present invention is to provide a manufacturing method for reducing the thickness of a tapered portion or a sleeve portion without reducing the thickness of a straight tube portion of a catheter balloon formed by biaxially stretching blow molding a parison.

  As a result of repeated studies to solve the above-mentioned problems, a method for heating and thinning the balloon taper portion and the sleeve portion using laser light has been invented.

  According to the manufacturing method of the present invention, only the portion that is irradiated with the laser beam is heated, so that the taper portion and the sleeve portion can be tapered without irradiating and stretching the laser spot without reducing the straight tube portion, The sleeve portion can be thinned.

  In the present invention, the polymer material used as the balloon material is not particularly limited, and polyester, polyamide, polyester elastomer, polyamide elastomer, polyolefin, polyurethane, and the like can be used. Moreover, the blend of 2 or more types of materials may be sufficient. Moreover, you may take the multilayered structure of two or more types of materials.

  In the balloon manufacturing method of the present invention, for example, the apparatus shown in FIG. 1 is used to perform biaxial stretch blow molding of the balloon. That is, a balloon parison 1 having a material, diameter, and thickness suitable for being molded into a balloon is introduced into the mold 2, the mold 2 is heated, and an axial direction of the balloon molding portion 3 of the balloon parison 3 is introduced. The change in stress is detected by the force gauge 4, and the fixing portions 5 and 6 are moved on the slide table 7 in the axial direction while holding the parison 1 for the balloon, and at the same time, the expansion fluid 8 is injected into the parison. Then, the parison is inflated, the inside 2 of the mold is further heated, and the expansion fluid 8 is injected into the parison to form a balloon. Thereafter, the mold 2 is cooled and the balloon is taken out.

  In the balloon manufacturing method of the present invention, the step of irradiating the taper portion and the sleeve portion by irradiating a laser beam is performed using, for example, the apparatus shown in FIG. Both ends of the biaxially stretched blow molded balloon 9 are fixed by the fixing portions 10 and 11, and the laser beam 13 is irradiated only to the tapered portion and the sleeve portion without irradiating the balloon straight tube portion by the laser irradiation device 12, The balloon taper part and the sleeve part are stretched by moving the fixing part 11.

  Here, only the sleeve portion or only the taper portion may be irradiated with the laser beam.

  In the balloon manufacturing method of the present invention, the laser emission source is not particularly limited, but carbon dioxide as the emission source is a wavelength band in which the balloon material of polyester or nylon has an appropriate absorption, high output and low cost. It is desirable because it is. Rather than irradiating laser light from one direction, it is desirable to irradiate simultaneously from multiple directions in order to achieve uniform stretching. Further, after the taper portion and / or the sleeve portion is stretched, the balloon may be inserted again into the mold and re-expanded.

The stretched balloon sleeve portion has a thickness t _c , where the diameter of the straight tube portion is D _a , the thickness of the straight tube portion is t _a, and the diameter of the sleeve portion is D _c :
_{t c (D c -t c)} <0.70t a (D a -t a)
It is desirable that the thickness satisfies the relationship:
_{t c (D c -t c)} <0.60t a (D a -t a)
It is more desirable to satisfy this relationship.
Expression 1 indicates that the cross-sectional area of the sleeve portion is smaller than 0.70 times that of the straight pipe portion, and indicates that the sleeve portion is extended more than the straight pipe portion.

The film thickness of the taper part is expressed by the equation when the film thickness of the intermediate part of the taper part is t _b and the diameter of the intermediate part is D _b :
_{t b (D b -t b)} <0.80t a (D a -t a)
It is desirable to satisfy the relationship:
_{t b (D b -t b)} <0.70t a (D a -t a)
It is more desirable to satisfy this relationship.

  FIG. 3 is a schematic sectional view showing an embodiment of the balloon catheter of the present invention. In the balloon catheter of the present invention, as shown in FIG. 3, the catheter shaft for joining the balloon has at least a distal portion, an inner tube 14 having an open distal end and a first lumen 14L, and a distal end which is the inner tube. If the structure is composed of the outer tube 15 that is located on the proximal side of the distal end of the tube, is arranged substantially coaxially with the inner tube, and has the second lumen 15L between the inner tube, The material type which comprises the said inner tube 14 and the said outer tube 15 is not specifically limited. That is, existing materials such as polyolefin, polyamide, polyester, polyurethane, polyimide, polyolefin elastomer, polyamide elastomer, polyester elastomer, and polyurethane elastomer can be used, and combinations of material types of the inner tube 14 and the outer tube 15 are also particularly limited. The material having physical properties according to the purpose of use can be selected.

  Further, the method for joining the balloon 16 to the inner tube 14 and the outer tube 15 is not particularly limited, and it goes without saying that a known method such as heat welding or adhesion using an adhesive can be employed in the joining portion 17. In addition, one or a plurality of radiopaque markers 18 can be imparted to the inner tube 14 existing inside the balloon 16 without limiting the effects of the present invention.

Example 1
A polyamide-based elastomer PEBAX7233SA01 (manufactured by Elf Atchem) was extruded by a predetermined method to prepare a parison having an outer diameter of 1.14 mm and an inner diameter of 0.51 mm. This parison was inserted into a balloon mold having a straight tube diameter of 3.0 mm, the mold temperature was heated to 90 ° C., and both sides of the parison were stretched by 15 mm each, and simultaneously pressurized nitrogen was blown into the parison. After inflating, the mold was heated to 110 ° C., and then the mold was cooled with water to take out the balloon from the mold. At this time, the thickness of the straight pipe portion was 0.028 mm.

  A mandrel was inserted into the balloon distal sleeve, and the sleeve was irradiated with CO2 laser light and stretched. The diameter of the sleeve portion before stretching was 1.02 mm, and the wall thickness was 0.090 mm. After stretching, the sleeve portion had a diameter of 1.00 mm and a wall thickness of 0.050 mm. The thickness of the straight pipe portion after stretching was 0.028 mm, and did not change compared to before stretching.

  The cross-sectional area of the sleeve part after stretching is 0.57 times the cross-sectional area of the straight pipe part, which indicates that only the sleeve part was stretched and thinned.

(Example 2)
The same parison as in Example 1 was used. This parison was inserted into a balloon mold having a straight tube diameter of 3.0 mm, the mold temperature was heated to 90 ° C., and both sides of the parison were stretched by 15 mm each, and simultaneously pressurized nitrogen was blown into the parison. After inflating, the mold was heated to 110 ° C., and then the mold was cooled with water to take out the balloon from the mold. At this time, the thickness of the straight pipe portion was 0.028 mm.

  The taper portion and the sleeve portion were irradiated with CO2 laser light and stretched. The diameter of the sleeve portion before stretching was 1.02 mm, and the wall thickness was 0.090 mm. The diameter of the taper part middle part before extending | stretching was 2.01 mm, and wall thickness was 0.043 mm. The same mold as in the blow molding was heated to 110 ° C., and the balloon was expanded again in the mold.

  After stretching and re-expansion, the sleeve portion had a diameter of 1.02 mm and a wall thickness of 0.050 mm. After stretching and re-expansion, the diameter of the intermediate portion of the tapered portion was 2.01 mm, and the wall thickness was 0.028 mm. The thickness of the straight pipe portion after re-expansion was 0.028 mm, and did not change compared to before stretching.

  The cross-sectional area of the sleeve part after stretching is 0.56 times the cross-sectional area of the straight pipe part, and the cross-sectional area of the taper part intermediate part after stretching is 0.67 times the cross-sectional area of the straight pipe part. It shows that there was an effect of thinning.

(Comparative Example 1)
Using the same parison as in Example 1, this parison was inserted into a balloon mold having a straight pipe portion diameter of 3.0 mm, the temperature of the mold center was heated to 90 ° C., and both sides of the parison were stretched by 15 mm each. At the same time, after the pressurized nitrogen is blown into the parison and inflated, the mold is further heated to further thin the balloon sleeve part, and both ends of the parison are further stretched by 15 mm each, and the middle part of the mold is washed with water. The balloon was taken out from the mold after cooling with the above.
At this time, the outer diameter of the balloon sleeve portion was 1.02 mm, and the inner diameter was 0.90 mm. The film thickness of the straight tube portion of the balloon was 0.027 mm.

  The balloon was put on a stretching apparatus, and the taper portion and the sleeve portion were heated and stretched with warm air. The same mold as in the blow molding was heated to 110 ° C., and the balloon was expanded again in the mold. The diameter of the straight pipe part after stretching and re-expansion was 3.0 mm, and the wall thickness was 0.026 mm. The diameter of the sleeve portion after stretching and re-expansion was 1.02 mm, and the thickness of the sleeve portion was 0.070 mm.

  The cross-sectional area of the sleeve part after stretching and re-expansion is 0.86 times the cross-sectional area of the straight pipe part after stretching and re-expansion. As a result of stretching to the straight pipe part, the effect of stretching only the sleeve part was small Is shown.

  Thus, in the method of heating and drawing with warm air, the thin pipe is thinned as a result of being drawn to the straight pipe portion, and the performance of breaking pressure and dimensional stability is lowered.

  In the method for manufacturing the balloon of Examples 1 and 2, the thickness of the tapered portion and the sleeve portion of the balloon manufactured by biaxial stretch blow molding of the parison is reduced by post-stretching. The balloon catheter on which the balloon manufactured by the manufacturing method of Examples 1 and 2 is mounted has good passage performance because the sleeve portion and the tapered portion are thin. According to the balloon manufacturing method of the present invention, a high-performance balloon catheter can be obtained.

Balloon blow molding equipment Balloon stretcher Balloon catheter schematic cross section

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Parison 2 Mold 3 Balloon molding part 4 Force gauge 5 Fixed part 6 Fixed part 7 Slide table 8 Expansion fluid 9 Balloon 10 Fixed part 11 Fixed part 12 Laser irradiation apparatus 13 Laser beam 14 Inner tube 14L First lumen 15 Outer tube 15L Second lumen 16 Balloon (Straight pipe part)
17 Joint 18 Radiopaque marker 19 Balloon sleeve (proximal balloon side)
20 Balloon taper (proximal balloon side)
21 Balloon taper (balloon distal side)
22 Balloon sleeve (balloon distal side)

Claims (2)

  A method of manufacturing a catheter balloon by biaxial stretching blow molding of a parison, wherein after the balloon is biaxial stretching blow molding, the balloon taper portion and sleeve portion are heated by laser light to be stretched and thinned. A method for producing a catheter balloon.   A balloon catheter comprising a balloon manufactured by the method according to claim 1.

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