JP2003326589A - Method for manufacturing balloon, and method for manufacturing catheter balloon by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for stably manufacturing a balloon, in a method for manufacturing a catheter balloon made by biaxially stretching and blow- molding a parison consisting of a polyamide elastomer. <P>SOLUTION: In biaxially stretching and blow-molding the parison consisting of the polyamide elastomer, an inner diameter of a section forming a balloon straight tube section in a mold is made 4 to 7 times that of the prison to manufacture the balloon. More preferably, the parison one end or both ends of which has an outer diameter of 0.4 to 0.9 times that of the central part of the parison is biaxially stretched and blow-molded to manufacture the balloon. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a balloon and a method for manufacturing a catheter balloon using this balloon.

[0002]

2. Description of the Related Art Conventionally, when a stenosis or occlusion occurs in a blood vessel such as a blood vessel, an angioplasty technique for expanding the stenotic or occluded portion of the blood vessel to improve blood flow on the peripheral side of the blood vessel. (PTA: Percutaneous Transluminal A
ngioplasty, PTCA: Percutaneous Transluminal
Coronary Angioplasty, etc.) has numerous surgical procedures in many medical institutions and has become common as surgery in cases of this type.

Catheter balloons are used in sets of guide catheters and guidewires to primarily dilate the stenosis of the coronary arteries. In angioplasty using this catheter balloon, first, a guide catheter is inserted from the femoral artery, the tip is positioned at the entrance of the coronary artery via the aorta, and then the guide wire piercing the catheter balloon is used to narrow the coronary artery. Advance beyond the site, then advance the catheter balloon along the guide wire, inflate the balloon while it is in the stenosis to expand the stenosis, and then deflate the balloon to remove it outside the body. To do. However, catheter balloons are not limited to the treatment of arterial stenosis, such as coronary arteries, but are useful for many medical applications including insertion into various blood vessels as well as into various body cavities.

Balloons are usually produced by biaxial stretch blow molding of a single-hole tube. In particular, the single-hole tube used for forming a catheter balloon is called a parison for catheter balloon. Hereinafter, a parison for a catheter balloon will be simply called a parison. Parisons are often manufactured by extrusion molding a thermoplastic resin. In extrusion molding, a parison of a desired size can be obtained by adjusting extrusion conditions such as a die shape, a set temperature of an extruder, a discharge rate, a speed for drawing a balloon parison, and an air pressure.

On the other hand, there are various sizes of catheter balloons, and parisons corresponding to the respective sizes have been used to produce balloons of a desired size. However, in the case of a balloon made of a polyamide elastomer, a balloon of a size that has been conventionally used may not be bulged if it is biaxially stretch blow molding conditions slightly, or it may not be bulged as soon as it is bulged. It was Even if it could be molded, it was difficult to produce balloons at a high yield, because cracks and pinholes were not formed on the balloon surface, and the sleeve portion did not swell.

In this situation, it is known that the yield can be improved by using a parison having a high dimensional accuracy, that is, a parison having a constant inner and outer diameters and a high roundness and concentricity. However, this also makes it difficult to produce balloons with a high yield.

[0007]

SUMMARY OF THE INVENTION In view of the above situation, an object of the present invention is to provide a method for stably producing a balloon by biaxially stretch blow molding a parison made of a polyamide elastomer. To provide.

[0008]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventor has found that when a parison made of a polyamide elastomer is biaxially stretch blow molded,
The inner diameter of the part that forms the balloon straight pipe part in the mold,
It has been found that by setting the inner diameter of the parison to be 4.0 times or more and 7.0 times or less, the molding defects in the biaxial stretch blow molding process can be reduced and the balloon can be stably produced.

When the parison made of polyamide elastomer is biaxially stretch blow-molded, the inner diameter of the portion forming the balloon straight pipe portion of the mold is 4.0 times or more the inner diameter of the central portion of the parison, and 7. By making the outer diameter of one end or both ends of the parison smaller than 0 times or less than the outer diameter of the central part of the parison, the molding yield of the balloon can be increased and the parison of the parison required for this purpose can be obtained. Outer diameter of sleeve part of any size without being affected by outer diameter,
It was possible to form a balloon with an outer diameter of the tapered portion. That is, even if the parison outer diameter selected to increase the molding yield is thicker than the dimensions of the sleeve portion and taper portion of the balloon to be created, the above method can form a balloon of an intended size. Is possible.

In order to form the above parison,
It has been found that a method of heating the one or both ends to a temperature higher than room temperature to stretch the parison can be preferably used.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is for biaxially stretch blow molding a parison made of a polyamide elastomer.
The inner diameter of the part that forms the balloon straight pipe part in the mold,
This is a method of manufacturing a balloon in which the inner diameter of the parison is 4.0 times or more and 7.0 times or less.

When the inner diameter of the portion forming the balloon straight pipe portion in the mold is 7.0 times or more the inner diameter of the parison,
Depending on the biaxially stretch blow molding conditions, it does not swell at all, or the rate of swelling and bursting simultaneously increases. Even if the molding can be performed, a satisfactory breaking pressure cannot be achieved, or defective appearance such as cracks, cracks, pinholes, dents, and unexpanded portions is likely to occur. On the other hand, the inner diameter of the portion of the mold forming the straight tube portion of the balloon is 4.
If it is set to 0 times or less, the parison becomes thick, so it cannot be usually inserted into the mold and cannot be molded, or even if the both ends or one end of the parison is stretched so that it can be inserted into the mold, the stretch ratio must be extremely large. To have to
It is not preferable because the capacity of the stretching device is exceeded or the parison is broken. Even if the balloon can be stretched, the balloon is likely to have a poor appearance such as a crack due to excessive stretching.

As the polyamide elastomer used as a raw material for the balloon of the present invention, a block copolymer comprising a hard segment and a soft segment is used, preferably a hard segment comprising a polyamide and a soft segment comprising a polyether. The block copolymer used in the present invention is used. Further, the polyamide constituting this hard segment includes polyamide 6, 6-6, 6-10, 6
Although -12, 11, 12 and the like can be used, polyamide 12 is particularly preferable. Polyethylene glycol, polypropylene glycol, polytetramethylene glycol and the like can be used as the polyether constituting the soft segment, and polytetramethylene glycol is particularly preferable. On the other hand, as the hardness of the polyamide-based elastomer, any hardness can be used depending on the flexibility required for the balloon, but a Shore D hardness of 25 to 72 is preferable, and a Shore D hardness of 50 is more preferable. 72 ones are used.

The method for producing the parison used for the balloon of the present invention is not particularly limited, but it is generally produced by extrusion molding.

In the method for manufacturing a balloon of the present invention, it is desirable that the parison has high dimensional accuracy. A gear pump for molding a balloon parison with high dimensional accuracy, an outer diameter control mechanism that adjusts the take-up speed to keep the outer diameter of the balloon parison constant, and an ultrasonic wave that measures the thickness of the balloon parison during extrusion molding. It is preferable to use an on-line wall thickness measuring device.

In order to stably manufacture the balloon,
It is desirable for the parison to be free of foreign material and it is desirable to use a filter during extrusion to make such a parison by extrusion.

FIG. 1 is a schematic sectional view showing an embodiment of the balloon of the present invention. The balloon of FIG. 1 has a straight pipe portion 2 that expands or contracts by the introduction of a pressure fluid, and a straight pipe portion 2
Proximal side taper part 3a and distal side taper part 3b that are connected to both ends of the taper and decrease in diameter toward the outside, and cylindrical proximal side sleeve part 4a and distal side sleeve that are connected to these taper parts 3a and 3b And part 4b.

The balloon of the present invention can be manufactured using, for example, the apparatus shown in FIG. A typical manufacturing method will be described below, but the present invention is not limited thereto. The balloon parison 5 is introduced into the mold straight tube portion 6, the mold distal end portion 7a, and the mold proximal end portion 7b, and the molds 6, 7a, 7b are heated to form a balloon parison balloon. The force gauge 9 measures the change in stress in the axial direction of the part 8.
And the fixing parts 10 and 11 are moved on the slide table 12 in the axial direction and opposite sides while holding the balloon parison 5 at the same time, and at the same time, the expansion fluid 13 is injected into the parison to inflate the parison. The molds 6, 7a, 7b are cooled to produce a balloon.

The temperature of the mold during biaxial stretch blow molding may be controlled by heating with an electric heater to circulate water around the mold to cool it, or by circulating a heat medium around the mold to heat the mold. Although various methods such as cooling can be used, it is easy to control the temperature of the center and both sides of the mold individually,
A method of heating with an electric heater and circulating water around the mold to cool it is desirable because it is easy to set the temperature in several steps within one molding cycle.

In the method of manufacturing a balloon of the present invention, since it is necessary to establish a specific relationship between the inner diameter of the portion forming the balloon straight pipe portion of the mold and the inner diameter of the central portion of the parison, a uniform outer diameter and inner diameter can be obtained. When the parison is used, it is difficult to make the outer diameter, the inner diameter, and the wall thickness of the taper portion and the sleeve portion into desired dimensions. That is, there is a problem that the outer diameter of the parison becomes thicker than either one of the mold distal end and the mold proximal end, or both ends of the mold, and the parison cannot be inserted into the mold.

In the present invention, in such a case, the inner diameter of the portion forming the balloon straight tube portion in the mold is 4.0 times or more and 7.0 times or less the inner diameter of the central portion of the parison, and further, By making the outer diameter of one end or both ends of the parison smaller than the outer diameter of the central portion of the parison, the above problem can be avoided. According to this method, it is possible to form a balloon having a taper portion and a sleeve portion of an arbitrary size without being affected by the size of the parison required for this, while enabling stable production of the balloon. Becomes Generally, from the viewpoint of the permeability of the stenosis,
It is desired to reduce the diameter and the thickness of the tapered portion and the sleeve portion within a range that satisfies the required pressure resistance characteristics. The "central portion" referred to here depends on the required shape of the balloon, but the length of the straight tube portion of the balloon is 0. It means a portion having a length of 3 times or more and 1.0 times or less. On the other hand, the terms “one end” and “both ends” as used herein mean a portion other than the central portion of the parison, depending on the required shape of the balloon.

In the parison used in the present invention, the outer diameter of one end or both ends is smaller than the outer diameter of the central part of the parison, the outer diameter of one end or both ends is 0.
A dimension of 4 times or more and 0.9 times or less is suitable for forming a balloon size such as a PTCA catheter balloon or a PTA catheter balloon which has many applications.

The above method not only improves the insertability of the parison into the mould, but also adjusts the length of one or both ends of the parison if necessary (ie, said one or both ends). (The length is adjusted so that the portion becomes the taper portion of the balloon, and further the sleeve portion), and the taper portion and the sleeve portion of the balloon can be thinned.

Here, in order to form a parison for use in the present invention in which the outer diameter of one end or both ends is smaller than the outer diameter of the central part of the parison, one end or both ends is heated to a temperature higher than room temperature. The method of stretching the parison can be preferably used. Especially in order to prevent the size of the center part from changing,
It is preferable to heat and stretch only one end or both ends to a temperature higher than room temperature in a state where the central portion is not heated and is cooled in some cases.

Such stretching of the parison can be carried out, for example, by using the apparatus shown in FIG. The balloon parison 5 is fixed to the fixing portions 16 and 17, and one side of the balloon parison 5 is heated to a temperature higher than room temperature and is sandwiched between the upper heater 14 and the lower heater 15 so that the parison and the heater do not come into contact with each other, and the fixing portion 16 is fixed. Axial slide table 18
It is moved up and stretched in the axial direction, and then the other side is similarly sandwiched between the upper heater 14 and the lower heater 15,
While the center of the parison is left unstretched, the fixed portion 17 is moved in the axial slide table 18 shape and stretched in the axial direction. Stretching may be performed on only one side. In general, the characteristics required on the proximal side and the distal side of the balloon are often different, and it is preferable to adjust each dimension at each of these positions to a different value. It is preferable to have different values for the side and the distal side. In this case, do the stretching of the parison on one side or
When drawing at the same time, it can be realized by controlling the heating temperature separately.

The catheter balloon using the balloon produced by the manufacturing method of the present invention can be used in all body cavities and blood vessels of the human body, and more preferably in coronary arteries, blood vessels of limbs, artificial blood vessels and the like. .

[0027]

The present invention will be described in more detail based on the following examples and comparative examples, which should not be construed as limiting the invention in any way.

(Example 1) Polyamide elastomer P
EBAX7033SA01 (manufactured by Elf Atchem) was extrusion-molded to prepare a parison having an outer diameter of 0.94 mm and an inner diameter of 0.51 mm.

Both ends of the parison were heated by a pair of heaters maintained at 150 ° C. and stretched, and the parison central portion 10 mm was left unstretched, and the outside diameter was 0.66 mm on both the right and left sides.

The parison was held at 110 ° C., the diameter of the straight pipe portion was 3.0 mm, the diameter of the proximal sleeve portion was 0.98 mm,
A balloon having an outer diameter of 3.0 mm and a wall thickness of 17 μm was formed by performing biaxial stretch blow molding at a nitrogen pressure of 3.5 MPa and an axial stretch distance of 46 mm in a die having a distal sleeve portion diameter of 0.74 mm. The inner diameter of the portion forming the balloon straight pipe portion in the mold was 5.9 times the inner diameter of the central portion of the parison.
Molding was performed 50 times in the same manner, but a balloon could be formed without bursting 50 times. A visual inspection was performed on 50 created balloons. In the visual inspection, the surface of the balloon was inspected for cracks, cracks, pinholes, dents, unexpanded portions, and other defects. All balloons had no poor appearance. Good product rate = (number of good products) /
The results calculated as (the number of parisons tried to be molded) are shown in Table 1.

The prepared balloon was placed in a water tank filled with physiological saline at 37 ° C., and 0.2a of physiological saline was used.
The pressure was increased by tm. Table 1 shows the results obtained by maintaining the pressure for 1 second, increasing the pressure until the balloon ruptures, and measuring the balloon rupture pressure. The measured value is an average value of n = 3. (Example 2) Polyamide elastomer PEBAX70
33SA01 (manufactured by Elf Atchem) is extruded,
A parison having an outer diameter of 0.86 mm and an inner diameter of 0.51 mm was prepared.

The both ends of the parison were heated by a heater kept at 150 ° C. and stretched, and the parison central part 10 m
m is left unstretched and the outside diameter is 0.6 on both right and left sides.
It was set to 0 mm.

The parison was held at 110 ° C., the diameter of the straight pipe portion was 3.0 mm, the diameter of the proximal sleeve portion was 0.98 mm,
A balloon having an outer diameter of 3.0 mm and a wall thickness of 16 μm was formed by performing biaxial stretch blow molding at a nitrogen pressure of 3.5 MPa and an axial stretch distance of 46 mm in a die having a distal sleeve portion diameter of 0.74 mm. The inner diameter of the portion forming the balloon straight pipe portion in the mold was 5.9 times the inner diameter of the central portion of the parison.
Molding was performed 50 times in the same manner, but a balloon could be formed without bursting 50 times. A visual inspection was performed on 50 created balloons. In the visual inspection, the surface of the balloon was inspected for cracks, cracks, pinholes, dents, unexpanded portions, and other defects. All balloons had no poor appearance. Table 1 shows the non-defective product rate = (the number of non-defective products / the number of parisons tried to be molded).

The results of measuring the breaking pressure of the balloon in the same manner as in Example 1 are shown in Table 1. (Example 3) Polyamide elastomer PEBAX70
33SA01 (manufactured by Elf Atchem) is extruded,
A parison having an outer diameter of 0.80 mm and an inner diameter of 0.51 mm was prepared.

The both ends of the parison were heated by a heater kept at 150 ° C. and stretched, and the parison central part 10 m
m is left unstretched and the outside diameter is 0.6 on both right and left sides.
It was set to 0 mm.

The parison was held at 110 ° C., the diameter of the straight tube portion was 3.0 mm, the diameter of the proximal sleeve portion was 0.98 mm,
A balloon having an outer diameter of 3.0 mm and a wall thickness of 16 μm was formed by performing biaxial stretch blow molding at a nitrogen pressure of 3.5 MPa and an axial stretch distance of 46 mm in a die having a distal sleeve portion diameter of 0.74 mm. The inner diameter of the portion forming the balloon straight pipe portion in the mold was 5.9 times the inner diameter of the central portion of the parison.
Molding was performed 50 times in the same manner, but a balloon could be formed without bursting 50 times. A visual inspection was performed on 50 created balloons. In the visual inspection, the surface of the balloon was inspected for cracks, cracks, pinholes, dents, unexpanded portions, and other defects. All balloons had no poor appearance. Table 1 shows the non-defective product rate = (the number of non-defective products / the number of parisons tried to be molded).

The results of measuring the breaking pressure of the balloon in the same manner as in Example 1 are shown in Table 1.

Example 4 Polyamide Elastomer P
EBAX7033SA01 (manufactured by Elf Atchem) was extrusion-molded to prepare a parison having an outer diameter of 0.86 mm and an inner diameter of 0.44 mm.

Both ends of the parison were heated by a heater kept at 150 ° C. and stretched to stretch the parison central portion 9 mm.
Is left unstretched and has an outer diameter of 0.60 on both the right and left sides.
mm.

The parison was held at 110 ° C., the diameter of the straight pipe portion was 3.0 mm, the diameter of the proximal sleeve portion was 0.98 mm,
A balloon having an outer diameter of 3.0 mm and a wall thickness of 16 μm was formed by performing biaxial stretch blow molding at a nitrogen pressure of 3.5 MPa and an axial stretch distance of 36 mm in a die having a distal sleeve portion diameter of 0.74 mm. The inner diameter of the portion forming the balloon straight pipe portion in the mold was 6.8 times the inner diameter of the central portion of the parison.
The same molding was carried out 50 times, but a balloon could be made without bursting 48 times and bursting twice. A visual inspection was performed on the 48 formed balloons. In the visual inspection, the surface of the balloon was inspected for cracks, cracks, pinholes, dents, unexpanded portions, and other defects. All balloons had no poor appearance. Table 1 shows the non-defective product rate = (the number of non-defective products / the number of parisons tried to be molded).

Table 1 shows the results of measuring the burst pressure of the balloon in the same manner as in Example 1.

(Example 5) Polyamide elastomer P
EBAX7033SA01 (manufactured by Elf Atchem) was extruded to form a parison having an outer diameter of 0.80 mm and an inner diameter of 0.44 mm.

Both ends of the parison were heated by a heater kept at 150 ° C. and stretched, and the parison central portion 9 mm
Is left unstretched and has an outer diameter of 0.60 on both the right and left sides.
mm.

The parison was held at 110 ° C., the diameter of the straight pipe portion was 3.0 mm, the diameter of the proximal sleeve portion was 0.98 mm,
A balloon having an outer diameter of 3.0 mm and a wall thickness of 16 μm was formed by performing biaxial stretch blow molding at a nitrogen pressure of 3.5 MPa and an axial stretch distance of 36 mm in a die having a distal sleeve portion diameter of 0.74 mm. The inner diameter of the portion forming the balloon straight pipe portion in the mold was 6.8 times the inner diameter of the central portion of the parison.
The same molding was carried out 50 times, but a balloon could be made without bursting 46 times and bursting 4 times. A visual inspection was performed on 46 formed balloons. In the visual inspection, the surface of the balloon was inspected for cracks, cracks, pinholes, dents, unexpanded portions, and other defects. All balloons had no poor appearance. Table 1 shows the non-defective product rate = (the number of non-defective products / the number of parisons tried to be molded).

Table 1 shows the results of measuring the burst pressure of the balloon in the same manner as in Example 1.

Example 6 Polyamide Elastomer P
EBAX7033SA01 (manufactured by Elf Atchem) was extrusion molded to prepare a parison having an outer diameter of 0.75 mm and an inner diameter of 0.44 mm.

The both ends of the parison were heated by a heater kept at 150 ° C. and stretched, and the central part of the parison was 9 mm.
Is left unstretched and has an outer diameter of 0.60 on both the right and left sides.
mm.

The parison was held at 110 ° C., the diameter of the straight pipe portion was 3.0 mm, the diameter of the proximal sleeve portion was 0.98 mm,
A balloon having an outer diameter of 3.0 mm and a wall thickness of 15 μm was formed by performing biaxial stretch blow molding at a nitrogen pressure of 3.5 MPa and an axial stretch distance of 36 mm in a die having a sleeve portion diameter of 0.74 mm on the distal side. The inner diameter of the portion forming the balloon straight pipe portion in the mold was 6.8 times the inner diameter of the central portion of the parison.
The same molding was performed 50 times, but a balloon could be made without bursting 44 times, and bursting 6 times. A visual inspection was performed on 44 formed balloons. In the visual inspection, the surface of the balloon was inspected for cracks, cracks, pinholes, dents, unexpanded portions, and other defects. All balloons had no poor appearance. Table 1 shows the non-defective product rate = (the number of non-defective products / the number of parisons tried to be molded).

The results of measuring the burst pressure of the balloon in the same manner as in Example 1 are shown in Table 1.

Example 7 Polyamide Elastomer P
EBAX7033SA01 (manufactured by Elf Atchem) was extrusion-molded to prepare a parison having an outer diameter of 1.04 mm and an inner diameter of 0.64 mm.

The both ends of the parison were heated by a heater kept at 150 ° C. and stretched, and the central part of the parison was 8 mm.
Is left unstretched and has an outer diameter of 0.60 on both the right and left sides.
mm.

The parison was held at 110 ° C., the diameter of the straight pipe portion was 3.0 mm, the diameter of the proximal sleeve portion was 0.98 mm,
A balloon having an outer diameter of 3.0 mm and a wall thickness of 19 μm was formed by performing biaxial stretch blow molding at a nitrogen pressure of 3.5 MPa and an axial stretching distance of 60 mm in a mold having a distal sleeve portion diameter of 0.74 mm. The inner diameter of the portion forming the straight balloon portion of the mold was 4.7 times the inner diameter of the central portion of the parison.
The same molding was performed 50 times, but a balloon could be formed without bursting 50 times. A visual inspection was performed on 50 created balloons. In the visual inspection, the surface of the balloon was inspected for cracks, cracks, pinholes, dents, unexpanded portions, and other defects. All balloons had no poor appearance. Table 1 shows the non-defective product rate = (the number of non-defective products / the number of parisons tried to be molded).

Table 1 shows the results of measuring the burst pressure of the balloon in the same manner as in Example 1.

Example 8 Polyamide Elastomer P
EBAX7033SA01 (manufactured by Elf Atchem) was extruded to form a parison having an outer diameter of 0.96 mm and an inner diameter of 0.64 mm.

The both ends of the parison were heated by a heater kept at 150 ° C. and stretched, and the central part of the parison was 8 mm.
Is left unstretched and has an outer diameter of 0.60 on both the right and left sides.
mm.

The parison was held at 110 ° C., the diameter of the straight pipe portion was 3.0 mm, the diameter of the proximal sleeve portion was 0.98 mm,
A balloon having an outer diameter of 3.0 mm and a wall thickness of 18 μm was formed by performing biaxial stretch blow molding at a nitrogen pressure of 3.5 MPa and an axial stretch distance of 60 mm in a die having a distal sleeve portion diameter of 0.74 mm. The inner diameter of the portion forming the straight balloon portion of the mold was 4.7 times the inner diameter of the central portion of the parison.
The same molding was performed 50 times, but a balloon could be formed without bursting 50 times. A visual inspection was performed on 50 created balloons. In the visual inspection, the surface of the balloon was inspected for cracks, cracks, pinholes, dents, unexpanded portions, and other defects. All balloons had no poor appearance. Table 1 shows the non-defective product rate = (the number of non-defective products / the number of parisons tried to be molded).

Table 1 shows the results of measuring the breaking pressure of the balloon in the same manner as in Example 1.

Example 9 Polyamide Elastomer P
EBAX7033SA01 (manufactured by Elf Atchem) was extruded to prepare a parison having an outer diameter of 0.91 mm and an inner diameter of 0.64 mm.

The both ends of the parison were heated by a heater kept at 150 ° C. and stretched, and the parison central portion 8 mm
Is left unstretched and has an outer diameter of 0.60 on both the right and left sides.
mm.

The parison was held at 110 ° C., the diameter of the straight pipe portion was 3.0 mm, the diameter of the proximal sleeve portion was 0.98 mm,
A balloon having an outer diameter of 3.0 mm and a wall thickness of 18 μm was formed by performing biaxial stretch blow molding at a nitrogen pressure of 3.5 MPa and an axial stretch distance of 60 mm in a die having a distal sleeve portion diameter of 0.74 mm. The inner diameter of the portion forming the straight balloon portion of the mold was 4.7 times the inner diameter of the central portion of the parison.
The same molding was performed 50 times, but a balloon could be formed without bursting 50 times. A visual inspection was performed on 50 created balloons. In the visual inspection, the surface of the balloon was inspected for cracks, cracks, pinholes, dents, unexpanded portions, and other defects. All balloons had no poor appearance. Table 1 shows the non-defective product rate = (the number of non-defective products / the number of parisons tried to be molded).

Table 1 shows the results of measuring the breaking pressure of the balloon in the same manner as in Example 1.

Comparative Example 1 Polyamide Elastomer P
EBAX7033SA01 (manufactured by Elf Atchem) was extruded to prepare a parison having an outer diameter of 0.80 mm and an inner diameter of 0.38 mm.

The both ends of the parison were heated by a heater kept at 150 ° C. and stretched, and the parison central part 10 m
m is left unstretched and the outside diameter is 0.6 on both right and left sides.
It was set to 0 mm.

The parison was held at 130 ° C., the diameter of the straight pipe portion was 3.0 mm, the diameter of the proximal sleeve portion was 0.98 mm,
A balloon having an outer diameter of 3.0 mm and a wall thickness of 13 μm was formed by performing biaxial stretch blow molding at a nitrogen pressure of 2.5 MPa and an axial stretch distance of 40 mm in a die having a sleeve portion diameter of 0.74 mm on the distal side. The inner diameter of the portion forming the straight balloon portion of the mold was 7.9 times the inner diameter of the central portion of the parison.
Molding was performed 50 times in the same manner, but almost all balloons burst during molding, and 15 balloons could be formed without bursting. A visual inspection was performed on the 15 created balloons. In the visual inspection, the surface of the balloon was inspected for cracks, cracks, pinholes, dents, unexpanded portions, and other defects. The five balloons had a poor appearance. Good product rate =
Table 1 shows (the number of non-defective products / the number of parisons tried to be molded).

Table 1 shows the results of measuring the burst pressure of the balloon in the same manner as in Example 1.

Comparative Example 2 Polyamide Elastomer P
EBAX7033SA01 (manufactured by Elf Atchem) was extrusion-molded to prepare a parison having an outer diameter of 0.75 mm and an inner diameter of 0.38 mm.

The both ends of the parison were heated by a heater kept at 150 ° C. and stretched, and the parison central part 10 m
m is left unstretched and the outside diameter is 0.6 on both right and left sides.
It was set to 0 mm.

The parison was held at 130 ° C., the diameter of the straight pipe portion was 3.0 mm, the diameter of the proximal sleeve portion was 0.98 mm,
A balloon having an outer diameter of 3.0 mm and a wall thickness of 13 μm was formed by performing biaxial stretch blow molding at a nitrogen pressure of 2.5 MPa and an axial stretch distance of 40 mm in a die having a sleeve portion diameter of 0.74 mm on the distal side. The inner diameter of the portion forming the straight balloon portion of the mold was 7.9 times the inner diameter of the central portion of the parison.
Molding was performed 50 times in the same manner, but almost all balloons burst during molding, and 22 balloons could be formed without bursting. A visual inspection was performed on 22 prepared balloons. In the visual inspection, the surface of the balloon was inspected for cracks, cracks, pinholes, dents, unexpanded portions, and other defects. The 14 balloons had a poor appearance. Table 1 shows the non-defective product rate = (the number of non-defective products / the number of parisons tried to be molded).

The results of measuring the burst pressure of the balloon in the same manner as in Example 1 are shown in Table 1.

(Comparative Example 3) Polyamide elastomer P
EBAX7033SA01 (manufactured by Elf Atchem) was extruded to prepare a parison having an outer diameter of 0.70 mm and an inner diameter of 0.38 mm.

The parison was held at 130 ° C., the diameter of the straight pipe portion was 3.0 mm, the diameter of the proximal sleeve portion was 0.98 mm,
A balloon having an outer diameter of 3.0 mm and a wall thickness of 12 μm was formed by performing biaxial stretch blow molding at a nitrogen pressure of 2.5 MPa and an axial stretch distance of 40 mm in a mold having a distal sleeve portion diameter of 0.74 mm. The inner diameter of the portion forming the straight balloon portion of the mold was 7.9 times the inner diameter of the central portion of the parison.
Molding was performed 50 times in the same manner, but almost all balloons burst during molding, and 13 balloons could be formed without bursting. A visual inspection was performed on the 13 formed balloons. In the visual inspection, the surface of the balloon was inspected for cracks, cracks, pinholes, dents, unexpanded portions, and other defects. The eight balloons had a poor appearance. Good product rate =
Table 1 shows (the number of non-defective products / the number of parisons tried to be molded).

Table 1 shows the results of measuring the breaking pressure of the balloon in the same manner as in Example 1.

(Comparative Example 4) Polyamide elastomer P
EBAX7033SA01 (manufactured by Elf Atchem) was extruded to form a parison having an outer diameter of 0.75 mm and an inner diameter of 0.34 mm.

The both ends of the parison were heated by a heater kept at 150 ° C. and stretched, and the parison central part 10 m
m is left unstretched and the outside diameter is 0.6 on both right and left sides.
It was set to 0 mm.

The parison was held at 130 ° C., the diameter of the straight pipe portion was 3.0 mm, the diameter of the proximal sleeve portion was 0.98 mm,
Biaxial stretch blow molding was performed in a mold having a diameter of the distal sleeve portion of 0.74 mm at a nitrogen pressure of 3.5 MPa and an axial stretch distance of 34 mm, but all of the 50 bursts were attempted during the 50 trials. . The inner diameter of the portion forming the balloon straight tube portion in the mold was 8.8 times the inner diameter of the central portion of the parison. Also, the mold temperature and nitrogen pressure were changed variously, but they all either burst or do not swell.
The balloon could not be molded.

Comparative Example 5 Polyamide Elastomer P
EBAX7033SA01 (manufactured by Elf Atchem) was extruded to form a parison having an outer diameter of 0.70 mm and an inner diameter of 0.34 mm.

The parison was held at 130 ° C., the diameter of the straight pipe portion was 3.0 mm, the diameter of the proximal sleeve portion was 0.98 mm,
Biaxial stretch blow molding was performed in a mold having a diameter of the distal sleeve portion of 0.74 mm at a nitrogen pressure of 3.5 MPa and an axial stretch distance of 34 mm, but all of the 50 bursts were attempted during the 50 trials. . The inner diameter of the portion forming the balloon straight tube portion in the mold was 8.8 times the inner diameter of the central portion of the parison. Also, the mold temperature and nitrogen pressure were changed variously, but they all either burst or do not swell.
The balloon could not be molded.

Comparative Example 6 Polyamide Elastomer P
EBAX7033SA01 (manufactured by Elf Atchem) was extruded to form a parison having an outer diameter of 0.66 mm and an inner diameter of 0.34 mm.

The parison was held at 130 ° C., the diameter of the straight pipe portion was 3.0 mm, the diameter of the proximal sleeve portion was 0.98 mm,
Biaxial stretch blow molding was performed in a mold having a diameter of the distal sleeve portion of 0.74 mm at a nitrogen pressure of 3.5 MPa and an axial stretch distance of 34 mm, but all of the 50 bursts were attempted during the 50 trials. . The inner diameter of the portion forming the balloon straight tube portion in the mold was 8.8 times the inner diameter of the central portion of the parison. Also, the mold temperature and nitrogen pressure were changed variously, but they all either burst or do not swell.
The balloon could not be molded.

Comparative Example 7 Polyamide Elastomer P
EBAX7033SA01 (manufactured by Elf Atchem) was extrusion-molded to prepare a parison having an outer diameter of 1.18 mm and an inner diameter of 0.81 mm.

Both ends of the parison were heated by a heater kept at 150 ° C. and stretched to be stretched to have an outer diameter of 0.60 mm on both the right and left sides.

The parison was held at 130 ° C., the diameter of the straight pipe portion was 3.0 mm, the diameter of the proximal sleeve portion was 0.98 mm,
Biaxial stretch blow molding was carried out in a mold having a diameter of the sleeve portion on the distal side of 0.74 mm with a nitrogen pressure of 3.5 MPa and an axial stretching distance of 64 mm. The inner diameter of the portion forming the balloon straight pipe portion in the mold was 3.7 times the inner diameter of the central portion of the parison. The same molding was performed 50 times, but a balloon could be formed without bursting 50 times. A visual inspection was performed on 50 created balloons. In the visual inspection, the surface of the balloon was inspected for cracks, cracks, pinholes, dents, unexpanded portions, and other defects. The 47 balloons had a poor appearance. Table 1 shows the non-defective product rate = (the number of non-defective products / the number of parisons tried to be molded).

Table 1 shows the results of measuring the burst pressure of the balloon in the same manner as in Example 1.

As shown in Table 1, when the inner diameter of the portion forming the straight balloon portion of the die is 4.0 times or more and 7.0 times or less the inner diameter of the central portion of the parison, it is high. It can be seen that the balloon can be produced at a molding yield, and that when any other parison is used, the molding yield becomes lower and the average breaking pressure becomes lower.

[0085]

[Table 1]

The inner and outer diameters of the parison used in the examples and comparative examples are shown in FIG. It is the inner diameter, not the outer diameter or the wall thickness of the parison that has a decisive effect on the molding yield, and if the ratio of the die diameter of the balloon straight tube to the parison inner diameter is 4.0 or more and 7.0 or less, the parison is used. It is clear from the figure that a high molding yield is obtained.

[0087]

As described above, in the manufacturing method of the present invention, the ratio of the die diameter to the parison inner diameter is 4.0 or more.
By using a parison of 0 or less, a high molding yield can be realized.

[Brief description of drawings]

FIG. 1 is a schematic view of a balloon according to the present invention.

FIG. 2 is a schematic view of a balloon molding device according to the present invention.

FIG. 3 is a schematic view of a parison stretching apparatus according to the present invention.

FIG. 4 is a diagram showing inner and outer diameters of parisons used in Examples and Comparative Examples of the present invention.

[Explanation of symbols]

1 balloon 2 Straight pipe section 3a Proximal taper part 3b distal taper 4a proximal sleeve part 4b distal sleeve part 5 parison 6 Mold center 7a Mold distal end 7b Mold proximal end 8 Balloon molding part of parison 9 Force gauge 10 Fixed part 11 Fixed part 12 slide table 13 Expansion fluid 14 Upper heater 15 Lower heater 16 Fixed part 17 Fixed part 18 slide table

Claims (5)

[Claims] 1. When a parison made of a polyamide elastomer is biaxially stretch blow-molded, the inner diameter of the portion forming the balloon straight tube portion of the die is 4.
A method for producing a balloon, which is 0 times or more and 7.0 times or less. 2. When a parison made of a polyamide elastomer is biaxially stretch blow-molded, the inner diameter of the portion forming the balloon straight pipe portion in the die is 4.0 times or more the inner diameter of the central portion of the parison, and 7. A method for producing a balloon, which is 0 times or less, and further, the outer diameter of one end or both ends of the parison is smaller than the outer diameter of the central portion of the parison. 3. The production of a balloon according to claim 2, wherein the outer diameter of one end or both ends of the parison is 0.4 times or more and 0.9 times or less the outer diameter of the central part of the parison. Method. 4. The method for producing a balloon according to claim 2 or 3, characterized in that a parison stretched by heating one end or both ends to a temperature higher than room temperature is used. 5. A balloon produced by the production method according to any one of claims 1 to 4, or a catheter balloon using the balloon.