JPH0999086A - Production of compliant balloon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing a balloon which has a high degree of pressure resistance performance and is expanded in the outside diameter at the time of expansion with an increase in expansion pressure. SOLUTION: A parison molded of a polyurethane resin having a 100% tensile stress of 20 to 60MPa and a glass transition temperature of -50 to 37 deg.C is heated to a temp. higher by at least 5 deg.C than the glass transition temp. of this polyurethane resin. The parison is then stretched 1.4 to 3.5 times. The stretched parison is then inserted into a balloon mold and the mold is heated to a temp. higher than the boundary temp. of a region where the polyurethane resin is in a glassy state and a region where the polyurethane resin attains a rubber state in the state of applying 0.3 to 2.0MPa pressure in the parison, by which the polyurethane resin is softened and the parison is expanded. This parison is brought into pressurized contact with the balloon mold and is pressed, by which the balloon is molded.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention mainly relates to blood vessels, biliary tracts,
The present invention relates to a method for producing a compliant balloon having high pressure resistance, which is useful as a balloon of a dilatation balloon catheter which is percutaneously or endoscopically inserted into a stenosis such as an esophagus to treat stenosis.

[0002]

2. Description of the Related Art In recent years, the cardiovascular system, digestive tract system, biliary system,
Various dilation procedures have been performed as a treatment means for a stenotic part of a luminal organ such as a urinary system. As one of the dilatation procedures, there is a method of destroying or evaporating a tissue with a high-frequency scalpel or a laser to expand a stenosis. Although this method is extremely effective, it requires technical skill, is liable to cause complications such as perforation and bleeding, and is not economical and therefore generally difficult to use.

[0003] As other methods, there have been reports of a method of scraping tissue of a stenosis by mechanical means and a method of expanding and maintaining a stenosis by a metal stent, but the former method is capable of restenosis. In the latter method, since the metal is semi-permanently implanted in the living body, a long-term observation of the prognosis is necessary. For this reason, it is hard to say that both are currently widely used methods. As for such a method, there is a mechanical dilation technique as the most widely used method. This method is roughly classified into a method using a dilator and a method using a balloon catheter.

[0004] The former method is a method in which a dilator having a tapered tip is introduced into a constriction to directly expand the constriction. However, the reach of the dilator is limited. When located farther from the insertion part, the part of the thick shaft that substantially expands does not reach the stenosis part and cannot be expanded sufficiently.When introduced into a part with strong bending, there is a risk of perforation by the dilator. It has some disadvantages. Regarding the risk of perforation, it has been reported that the dilator has a small hole through which the guide wire passes, the guide wire is passed through the stenosis in advance, and the dilator is pushed into the stent, but the scope of application is narrow. . Also, this method is not applicable to the cardiovascular system.

On the other hand, the method using a dilatation balloon catheter is a method in which a balloon is percutaneously or endoscopically introduced to a stenosis portion, and the balloon is inflated with high pressure to dilate the stenosis. Since this method uses a thin and flexible balloon catheter, it has a wider range of reachable areas than the method using a dilator, has excellent insertion properties, and has little invasiveness to a patient. Furthermore, in the case of dilation using an endoscope, it is possible to insert a balloon catheter through the forceps opening,
It is also possible to expand while actually observing the state of the narrowed portion.

A balloon inflation pressure of 0.3 to 2.0 MPa is required to expand the stenosis with a balloon. Moreover, the higher the pressure resistance of the balloon, the better from the viewpoint of safety. However, the pressure resistance of balloons of catheters currently on the market is not sufficient, which is a major reason why this technique is not widely used. Some catheter balloons currently on the market use polyethylene and polyolefin copolymers, but the pressure resistance of this is at most 1 MPa, and there is no room for expansion at high pressure. There is a problem with safety.

Several methods have been proposed as methods for solving this problem. For example, Japanese Patent Publication Sho-63-26
Japanese Patent No. 655 describes a balloon made of polyethylene terephthalate, and provides a balloon having a breaking force of 1.4 MPa or more. Further, JP-A-63-212373 and JP-A-3-57462 disclose balloons made of polyamide elastomer or nylon. However, although these materials have a high breaking pressure, they have the drawback that they cannot be bonded to the thermoplastic elastomer used as the material of the shaft or tube of the catheter, and their high pressure resistance cannot be sufficiently brought out.

To solve this problem, a method of using a polyethylene terephthalate or nylon catheter tube can be considered, but this one has a high hardness, a high rigidity, and is easily bent when bent, so that a bent living body can be used. It is not suitable as a tube material to be inserted into the lumen. Further, since these are highly crystalline resins, they have extremely high fluidity above the melting point, and there is a processing problem that it is difficult to maintain the shape of a molded article such as a balloon near the melting point.

As a method for improving the bonding strength between the balloon and the shaft or the tube, a balloon made of polyurethane is disclosed in Japanese Patent Application Laid-Open No. 4-500024. This product uses a polyurethane resin having a Shore hardness of about 75 D and a glass transition point of about 38 ° C. or higher to achieve a high withstand voltage, and has a withstand pressure performance of at least 0.7 MPa.

On the other hand, these balloons have a characteristic that their outer diameter is substantially constant regardless of the inflation pressure, and that the desired outer diameter at the time of inflation can be reliably obtained. However, reliably obtaining the desired outer diameter at the time of expansion may lead to inconvenience. For example, depending on the degree of stenosis, if the outer diameter of the used catheter when the balloon is inflated is too large, it may damage the intima of the lumen and induce complications. On the contrary, the outer diameter of the catheter used when the balloon is inflated is too small, and a balloon having a larger inflated outer diameter may be required. In this case, the use of a balloon catheter reduces invasion to the patient, but for example, in the case of biliary dilation, pain is an inevitable complication,
In order to minimize the patient's pain, it is desirable to carry out the balloon catheter exchange as little as possible.

[0011] Here, the inventors of the present invention have found that an outer diameter at the time of inflation increases at a constant rate as the balloon inflation pressure increases, and if a balloon having a high degree of pressure resistance is provided, it is a therapeutically effective means. I started research, thinking that it would be.
As a result of extensive studies on the relationship between various materials and their balloon expansion characteristics and pressure resistance, assuming that the adhesion between the balloon and the shaft of the catheter or the tube is good, it has certain specific physical properties. By using a polyurethane resin as a material, we have succeeded in developing a balloon that has a pressure resistance of at least 2 MPa and the outer diameter of the balloon when expanded is up to 45% as the balloon inflation pressure increases. The contents are disclosed in Japanese Patent Application No. 7-213848.

This is 0.1% in water at 37 ° C.
When the balloon outer diameter when the balloon is inflated at a pressure of MPa is r _0.1 and the balloon outer diameter when the balloon is inflated at a pressure of 1.5 MPa is r _1.5 , (r _1.5 −r _0.1 ) / r
_{As a} balloon that has an inflating property of _0.1 = 0.10 to 0.45 and is inserted into blood vessels, biliary tracts, esophagus, etc. percutaneously or endoscopically to expand and treat the stenosis. It was extremely effective.

[0013]

The present invention is mainly directed to blood vessels,
Provided is a method for producing a compliant balloon having high pressure resistance, which is useful as a balloon of a dilatation balloon catheter for percutaneously or endoscopically inserting into a stricture such as a biliary tract or an esophagus. To do.

[0014]

Means for Solving the Problems The inventors have made earnest studies on a method for manufacturing a balloon based on the above invention. In the process, we paid attention to the fact that the relationship between the balloon inflation pressure and the outer diameter when inflated changed depending on the manufacturing conditions of the balloon. Then, as a result of conducting experiments and analyzing factors during manufacturing, it was confirmed that the elongation degree of the parison and the molding temperature of the balloon are extremely significant. Therefore, the present invention provides the present invention by finding a manufacturing method capable of controlling the expansion characteristics of the balloon without impairing the high degree of pressure resistance, by carefully studying the relationship between the expansion degree of the parison, the molding temperature of the balloon, and the expansion characteristics of the balloon. Came to do.

The present invention has a 100% tensile stress of 20 to 60M.
1. A parison made of a polyurethane resin having a glass transition point of −50 to 37 ° C. at Pa is heated to a temperature that is at least 5 ° C. higher than the glass transition point of the polyurethane resin.
The parson that has been stretched 4 to 3.5 times and then stretched is introduced into a balloon mold, and 0.3 to 2.0 MPa is applied to the parison.
In the state where the pressure of is applied, the temperature of the mold is heated to a temperature higher than the boundary temperature between the region where the polyurethane resin is in the glass state and the region where it is in the rubber state to soften the polyurethane resin and expand the parison, A method for producing a compliant balloon, which comprises contacting and pressing a balloon mold to form the balloon.

As a method of producing balloons having different expansion characteristics, after expanding the parison by 1.4 to 1.8 times, the mold temperature is changed to a region where the polyurethane resin is in the glass state and a region where the polyurethane resin is in the rubber state. A method for producing a compliant balloon having a small expansion coefficient that is molded at a temperature that is at least 35 ° C. higher than the boundary temperature between the and, and after extending the parison by 1.8 to 3.5 times, the mold temperature is set to the polyurethane resin in a glass state. It is a method for producing a compliant balloon having a large expansion coefficient, which is formed at a temperature equal to or higher than the boundary temperature between the region and the region where the rubber state is achieved, and does not exceed the boundary temperature + 35 ° C. at the highest.

[0017]

First, materials used in the present invention will be described. To make balloons in accordance with the present invention, the specific types of polyurethane resins described below are used. The polyurethane resin usable in the present invention has a molecular weight of 2
After reacting an organic diisocyanate with a long-chain polyol composed of a repeating unit containing at least one of an ester bond, an ether bond, or a carbonate bond of 0 to 3000, at least one selected from water or a polyol compound. It is a thermoplastic polyurethane resin obtained by reacting two chain extenders. The molecular weight of this compound is required to be at least 80,000, preferably 120,000 or more in order to maintain the mechanical properties described later.

The organic diisocyanate used is not particularly limited, and any organic diisocyanate known in the art can be used, for example, 4,4'-methylenebis (phenylisocyanate), 4,4'-methylenebis (cyclohexylisocyanate). , 2,4-toluene diisocyanate, 2,6-toluene diisocyanate,
Examples include 1,4-phenylene diisocyanate and mixtures thereof. The chain extender used is not particularly limited, and any chain extender known in the art can be used,
For example, the diol compound is ethylene glycol,
1,3-propanediol, 1,4-butanediol,
1,5-pentanediol, 1,6-hexanediol, 1,3-cyclohexadiol, 1,4-cyclohexadiol, 1,4-cyclohexanedimethanol,
Examples include bisphenol A and mixtures thereof.

The polyurethane resin usable in the present invention is
It includes a thermoplastic polyurethane resin having a partially crosslinked structure introduced into the molecular chain or between the molecular chains. As a method for introducing a crosslinked structure, for example, in the above-mentioned step of synthesizing a polyurethane resin, a small amount of a polyethylene oxide-polypropylene oxide copolymer polyol is added to a long-chain diol for reaction, or a chain extender such as triol is used. There is a method of using a compound having three or more functional groups. Of course, the polyurethane resin used in the present invention is not limited to those produced by these means. Further, the polyurethane resin used in the present invention is required to have the physical properties described below.

First, the polyurethane resin is 20-60MP
It should have a 100% tensile stress of a, more preferably 25-50 MPa. The 100% tensile stress referred to here means a physical property value according to the measuring method of JIS K 7311. 100% tensile stress of polyurethane resin is 20M
When it is less than Pa, the balloon produced from this has a large creep, is poor in pressure resistance, and easily undergoes permanent deformation at a low inflation pressure, which is not preferable. A 100% tensile stress of more than 60 MPa is not preferable because the balloon becomes hard and becomes non-compliant.

Secondly, the polyurethane resin used in the present invention must have a glass transition point of -50 to 37 ° C, preferably -40 to 30 ° C. The glass transition point here is the boundary temperature at which the soft segment component in the polyurethane resin starts micro Brownian motion,
It is measured as the temperature at which the drop of the dynamic storage modulus starts in the dynamic viscoelasticity test or as the transition temperature from the glass state to the rubber state in the differential scanning calorimeter (DSC) analysis. If the glass transition temperature of the polyurethane resin is higher than 37 ° C, the micro-Brownian motion of the molecular chain of the soft segment component is frozen in the environment of 37 ° C or lower, which is the temperature at which the balloon is actually used, that is, inside the biliary tract or esophagus. Since it exhibits a glass state, a balloon made of this material is not preferable because it is hard and compliant characteristics cannot be obtained, and when the glass transition point is lower than -50 ° C, the elastic modulus decreases, so the balloon becomes too soft, It is not preferable because the pressure resistance decreases and permanent deformation easily occurs at a low expansion pressure.

Such a polyurethane resin can be obtained by synthesizing it based on a known technique such as a prepolymer method. Although the type of the polyol used as the soft segment component is limited, it is possible to use a commercially available product, for example, a product name “Isoplast” manufactured by Dow Chemical Co., a product name manufactured by Nippon Miractolan Co., Ltd. "Miractolane" is preferred.

Next, a method for manufacturing a compliant balloon according to the present invention will be described. First, as a first step, a polyurethane resin is melt-extruded to a thickness of 30 to 5
A parison having a diameter of 00 μm and an outer diameter of 0.5 to 3.0 mm is prepared. In order to produce a uniform balloon without uneven wall thickness, it is necessary to prepare a parison having a very small variation in outer diameter and wall thickness. For example, the variation of the outer diameter of the parison is within ± 1% of the reference value, the cross-sectional shape of the parison is visually a perfect circle, and the XY coordinate axis with the center of the parison cross section (circle) as the reference point 0. Think X
When the outer diameter of the parison on the axis is d _x and the outer diameter of the parison on the Y axis is d _y , the ratio d _x / d _y is in the range of 0.98 to 1.02, X, It can be raised that the standard deviation / average value (CV value) of the wall thicknesses of the four parisons on the Y axis is 0.05 or less.

In the second step, the molded parison is tensioned and stretched 1.4 to 3.5 times. According to the invention, it is then necessary to heat the parison to a temperature at least 5 ° C. above the glass transition point of the polyurethane resin to soften it. The parison is hard near the glass transition point,
Stretching is difficult, and if stretched forcibly, it may break, which is not preferable. Further, even if it can be extended, the outer diameter of the extended portion is not uniform, and the surface is rough, which is not preferable. There is no particular limitation on the heating method,
Although a hot water bath, a dryer, a drier, etc. can be used, the inventors prefer to use a hot water bath that can easily control the temperature and can apply heat uniformly.

The stretched parison is cooled in a tensioned state so as to maintain a stretched state of 1.4 to 3.5 times.
It is usually sufficient to carry out the cooling at room temperature, but from the viewpoint of improving work efficiency, the method of immersing in cooling in ice water is preferable. According to the present invention, the elongation of the parison is controlled to 1.4 to 3.5 times. When the elongation of the parison is less than 1.4 times, the balloon obtained from this has a 30% increase in the length direction of the balloon as the inflation pressure increases.
It is not preferable because the above remarkable stretching occurs, and if it is more than 3.5 times, the permanent strain of the parison after stretching is large,
It is not preferable because balloon molding becomes impossible.

The temperature at which the parison is stretched needs to be raised or lowered depending on the size and wall thickness of the parison used and the desired balloon expansion characteristics, but the parison stretched under the preferred conditions reheats the parison after cooling. At times, it is possible to see a phenomenon in which the length of the parison after expansion contracts by 10 to 60% in an instant, so this is one guide. That is, since the parison in which no shrinkage is observed has a high temperature at the time of elongation, or the heating and holding time thereof is too long, it is necessary to lower the temperature or shorten the heating and holding time.

In the third step, the stretched parison is inserted into a balloon mold, and the parison is filled with 0.3 to 2.0 MPa.
The pressure of the mold is applied to heat the mold to a temperature higher than the boundary temperature between the region where the polyurethane resin, which is the material of the parison, is in the glass state and the region where it is in the rubber state, to soften the polyurethane resin. , Inflate the parison. Since the parison which has started to expand comes into contact with the balloon mold, it is pressed and set in this state to complete the balloon molding.
After completion of the balloon molding, the mold is cooled to room temperature while the pressurized state of the parison is maintained. After the cooling is completed, the pressurized state of the parison is released, and the balloon is released.

According to the present invention, the pressure applied in the parison is adjusted to 0.3 to 2.0 MPa. When the pressure applied to the parison is 0.3 MPa or less, the parison does not expand, which is not preferable. When the pressure is 2.0 MPa or more, the parison bursts during molding, which is not preferable. Further, according to the present invention, the mold temperature is adjusted to a temperature higher than the boundary temperature between the region where the polyurethane resin forming the parison is in the glass state and the region where it is in the rubber state. If the temperature of the mold is below this boundary temperature, the softening of the polyurethane resin necessary for expanding the parison cannot be obtained, which is not preferable. The preferred mold temperature varies depending on the combination of the required compliant properties and the type of polyurethane resin used, but the elasticity of the polyurethane resin decreases near the melting point, the fluidity becomes strong, and the shape of the parison is maintained. This is not preferable as molding conditions because it becomes impossible.

The "boundary temperature between the region in which the polyurethane resin is in the glass state and the region in which it is in the rubber state" is the temperature at which the sudden drop of the dynamic storage elastic modulus is completed in the dynamic viscoelasticity test. Is measured as. Cooling of the mold after completion of molding may be performed rapidly to improve the molding efficiency, but it should be gradually cooled to increase the pressure resistance of the balloon. The inventors have experimentally confirmed that the pressure resistance of the slowly cooled balloon is better than that of the rapidly cooled balloon. The reason is required to be examined in detail, but it is presumed that slow cooling allows the molecular arrangement after molding to be more stable.

The size of the balloon depends on the luminal organ to be dilated, but generally speaking, in the vascular system, the outer diameter is 2 to 4 mm, the length is 20 to 40 mm, and the thickness of the balloon is 10 to 25 μm. System, biliary system has an outer diameter of 6 to 4
The thickness is 0 mm, the length is 20 to 100 mm, and the thickness of the balloon is 10 to 40 μm. The present invention can be applied to any of these balloons. Of course, the present invention does not limit the size of the balloon that can be manufactured to balloons having dimensions in this range.

The balloon manufactured according to the above-mentioned method has a balloon outer diameter of r _0.1 when the balloon is inflated at a pressure of 0.1 MPa in water at 37 ° C. and a balloon outer diameter when inflated at a pressure of 1.5 MPa. Balloon outer diameter is r _1.5
When you _{and, (r 1.5 -r 0.1) /} r 0.1 = 0.10~0.4
It has an expansion characteristic of 5.

According to the present invention, by adjusting the elongation of the parison and the temperature of the molding die in the above-described manufacturing method, (r _1.5 -r _0.1 ) / r _0.1 ≤0.25, or (r _1.5
-R _0.1) / r _0.1> it is possible to produce a balloon having a 0.25 expansion properties of the. Specifically, in order to obtain a balloon having an expansion property of (r _1.5 −r _0.1 ) / r _0.1 ≦ 0.25, the elongation of the parison is 1.4.
The mold temperature must be raised to at least 35 ° C. higher than the boundary temperature between the region in which the polyurethane resin forming the parison is in the glass state and the region in which the polyurethane resin forming the parison is in the rubber state. _In order to obtain a balloon having an expansion characteristic of _1.5 −r _0.1 ) / r _0.1 > 0.25, the elongation of the parison is set to 1.8 to 3.5 times, and the mold temperature is set to the polyurethane resin forming the parison. It is necessary to control the temperature to be equal to or higher than the boundary temperature between the region in the glass state and the region in the rubber state and not exceeding the boundary temperature + 35 ° C. at the highest.

Since it is not clear at present how the degree of extension of the parison and the temperature of the mold control the molecular arrangement of the polyurethane resin, it is impossible to state the theoretical proof of the present invention. However, the two factors of parison stretch and mold temperature are independent of each other, no interaction occurs, and the contribution of parison stretch to balloon expansion characteristics is greater than that of mold temperature. Has become clear at the stage of study leading to the present invention. Therefore, when it is necessary to strictly set (r _1.5 −r _0.1 ) / r _0.1 of the balloon, the mold temperature is the boundary temperature between the region where the polyurethane resin forming the parison is in the glass state and the region where it is in the rubber state. It is preferable to set the temperature to around + 35 ° C., take the parison extension degree to several levels, and make a trial to determine the final manufacturing conditions.

As described above, the balloon manufactured according to the present invention has both excellent pressure resistance and desired inflation characteristics, and is a luminal organ such as vascular system, digestive tract system, biliary tract system, urinary tract system or the like. It can be used very suitably as a balloon for dilatation treatment of a stenotic part. Next, the effects of the present invention will be described in more detail by showing examples.

[0035]

【Example】

(Example 1) 4836.94 g of poly (hexamethylene carbonate) diol having a molecular weight of 2000 and 4,4'-methylene bis (phenyl isocyanate) 2012.70
g in a reaction vessel with a jacket and reacting at 80 ° C. for 3 hours with stirring, and then 416.39 g of 1-cutting, 4-butanediol was added, and the mixture was stirred at 50 ° C. for 1 hour.
The reaction was performed for 0 minutes. The reaction is then transferred to a tray and 80
React at 16 ° C for 16 hours, then at 120 ° C for 16 hours, number average molecular weight 75,000, weight average molecular weight 240
, A Shore hardness of 74 D, a glass transition point of 10 ° C., a boundary temperature of 80 ° C. between a glassy region and a rubbery region, and 100% tensile stress of 34.5 MPa were obtained.

This product was crushed into pellets and melt-extruded to prepare a parison having a thickness of 260 μm and an outer diameter of 1.9 mm. Next, this parison was immersed in a hot water bath at 60 ° C., tension was applied to the parison to extend it to 2.7 times, and then the parison was placed in an ice water bath while maintaining the extended state to obtain a parison with an outer diameter of 1.15 mm. This parison has an outer diameter of 6 mm when expanded,
It was inserted into a mold of a balloon having a length of 40 mm, a pressure of 1.4 MPa was applied to the parison, and hot air was blown to the mold to heat the parison in the mold. The mold temperature was maintained at 110 ° C. to expand the parison, and the balloon molding was completed. After that, the mold was gradually cooled over 10 minutes, and the expansion characteristics and the breaking pressure of the taken out balloon were examined and summarized in Table 1.

The inflation characteristics are as follows: balloon outer diameter r _0.1 when the balloon is inflated in water at 37 ° C. under a pressure of _0.1 MPa, and balloon outer diameter r _1.5 when the balloon is inflated at a pressure of 1.5 MPa. Is measured with a caliper, and (r
_1.5- r _0.1 ) / r _0.1 was calculated and used as a scale. The breaking pressure was measured by immersing the balloon in water at 37 ° C., pressurizing the balloon at a rate of 0.2 MPa per 10 seconds, and measuring the pressure at the time of breaking.

(Example 2) The polycarbonate urethane parison prepared in Example 1 was immersed in a water bath at 60 ° C,
After applying tension and stretching it to 1.5 times, the parison with an outer diameter of 1.48 mm was obtained by immersing it in an ice water bath while maintaining the stretched state. This parison has an expanded outer diameter of 6 mm and a length of 4
The balloon was inserted into a mold of 0 mm in size, a pressure of 1.4 MPa was applied to the parison, and hot air was blown to the mold to heat the parison in the mold. The mold temperature was maintained at 140 ° C. to expand the parison, and the molding of the balloon was completed. After that, the mold was gradually cooled over 15 minutes, and the expansion characteristics and the breaking pressure of the taken out balloon were examined by the same method as in Example 1, and summarized in Table 1.

(Example 3) Shore hardness 68 D, glass transition point 8 ° C., boundary temperature between glassy region and rubbery region 70 ° C., 100% tensile stress 42.2 MP
Polyester type polyurethane of a "Miractran E57
4PNAT "(manufactured by Nippon Miractolan Co., Ltd.) was melt-extruded to prepare a parison having a wall thickness of 260 μm and an outer diameter of 1.9 mm. Then immerse the parison in a 70 ° C water bath,
After tension was applied and the film was elongated to 3.0 times, the parison with an outer diameter of 1.12 mm was obtained by immersing it in an ice water bath while maintaining the elongated state. Using this parison, outer diameter of 6m when expanded
m, insert into the mold of a balloon with a length of 40 mm,
A pressure of 1.4 MPa was applied to the parison, and hot air was applied to the mold to heat the parison in the mold. Mold temperature 100
The parison was inflated by holding at 0 ° C. to complete the molding of the balloon. After that, the mold was gradually cooled over 10 minutes, and the expansion characteristics and the breaking pressure of the taken out balloon were examined by the same method as in Example 1, and summarized in Table 1.

Example 4 The parison prepared in Example 3 was dipped in a hot water bath at 70 ° C., tensioned and stretched 1.5 times, and then, while maintaining the stretched state, it was immersed in an ice water bath,
A parison with an outer diameter of 1.45 mm was obtained. This parison was inserted into a balloon mold having an outer diameter of 6 mm and a length of 40 mm when inflated, a pressure of 1.4 MPa was applied to the parison, and hot air was applied to the mold to heat the parison in the mold. .
The mold temperature was maintained at 140 ° C. to expand the parison, and the molding of the balloon was completed. After that, the mold was gradually cooled over 15 minutes, and the expansion characteristics and the breaking pressure of the taken out balloon were examined by the same method as in Example 1, and summarized in Table 1.

(Comparative Example 1) Shore hardness 65D, glass transition point -20 ° C, boundary temperature 65 ° C between the region in the glass state and the region in the rubber state, 100% tensile stress 15MP
Polyester polyurethane of "a" Pandex T-5
070 "(manufactured by Dainippon Ink and Chemicals, Inc.) was melt-extruded to prepare a parison having a wall thickness of 260 μm and an outer diameter of 1.9 mm. Next, the parison was immersed in a hot water bath at 70 ° C., tension was applied to extend the parison to 3.0 times, and then the parison was placed in an ice water bath while maintaining the stretched state to obtain a parison with an outer diameter of 1.12 mm. Using this parison, insert it into the mold of a balloon with an outer diameter of 6 mm and a length of 40 mm when inflated, apply a pressure of 1.4 MPa to the parison, and apply hot air to the mold to apply heat inside the mold. The parison was heated. The mold temperature was maintained at 95 ° C. to expand the parison, and the molding of the balloon was completed. After that, the mold was gradually cooled over 10 minutes, and the expansion characteristics and the breaking pressure of the taken out balloon were examined by the same method as in Example 1, and summarized in Table 1.

(Comparative Example 2) The parison prepared in Comparative Example 1 was immersed in a hot water bath at 70 ° C, tensioned and stretched 1.5 times, and then the parison was immersed in an ice water bath while maintaining the stretched state.
A parison with an outer diameter of 1.50 mm was obtained. This parison was inserted into a balloon mold having an outer diameter of 6 mm and a length of 40 mm when inflated, a pressure of 1.4 MPa was applied to the parison, and hot air was applied to the mold to heat the parison in the mold. .
The mold temperature was maintained at 140 ° C. to expand the parison, and the molding of the balloon was completed. After that, the mold was gradually cooled over 15 minutes, and the expansion characteristics and the breaking pressure of the taken out balloon were examined by the same method as in Example 1, and summarized in Table 1.

(Comparative Example 3) Expanded outer diameter of 3 mm, length of 20 mm, thickness of 15 μm manufactured by Advanced Polymer Co., USA
m polyethylene terephthalate balloon,
The expansion characteristics and the burst pressure of the balloon were examined by the same method as in Example 1 and summarized in Table 1.

[0044]

[Table 1]

[0045]

As is clear from the evaluation results of Table 1,
The balloons shown in Examples 1 to 4 have a pressure resistance of at least 2 MPa, and it is possible to obtain a therapeutically sufficient inflation pressure. On the other hand, in the balloons shown in Comparative Examples 1 and 2, the polyurethane resin used was a material having a small 100% tensile stress, and therefore the pressure resistance performance is insufficient. The inflation characteristics of the balloons of Examples 1 to 4 are (r _1.5 −r _0.1 ) / r _0.1
= 0.10 to 0.45, the use of this balloon induces intimal damage of the lumen due to the use of an oversized balloon, and the therapeutic effect decreases due to the use of an undersized balloon. It is possible to eliminate the burden on the patient due to replacement with a balloon of a large size.

As in Examples 1 and 3, the parison was set to 1.8.
.About.3.5 times the mold temperature, and the mold temperature is equal to or higher than the boundary temperature between the region in which the polyurethane resin forming the parison is in the glass state and the region in which the polyurethane resin is in the rubber state.
The expansion characteristics of the balloon manufactured by controlling the temperature not to exceed 5 ° C are controlled to be 0.45 ≧ (r _1.5 −r _0.1 ) / r _0.1 > 0.25, and it is possible to greatly expand at high pressure. is there. In addition, as in Examples 2 and 4, the parison was set to 1.4-
Expansion of the balloon produced by stretching 1.8 times and setting the mold temperature to a temperature at least 35 ° C. higher than the boundary temperature between the region where the polyurethane resin forming the parison is in the glass state and the region where it is in the rubber state. The characteristic is 0.1 ≦ (r _1.5
It is controlled to −r _0.1 ) / r _0.1 ≦ 0.25, and it is possible to obtain intermediate expansion characteristics between the PET balloon of Comparative Example 3 and the balloons of Examples 1 and 3.

Thus, according to the manufacturing method of the present invention,
It is possible to manufacture balloons that have both excellent pressure resistance and desired expansion characteristics, and manufacture balloons for dilatation treatment of strictures of luminal organs such as vascular system, digestive tract system, biliary system, urinary system. It is extremely suitable as a method.

Claims (3)

[Claims] 1. A 100% tensile stress is 20 to 60 MPa.
Then, a parison made of a polyurethane resin having a glass transition point of −50 to 37 ° C. is heated to a temperature that is at least 5 ° C. higher than the glass transition point of the polyurethane resin, and then 1.4 to
After the stretched Parson was stretched 3.5 times, the stretched Parson was introduced into a balloon mold, and a pressure of 0.3 to 2.0 MPa was applied to the parison. Manufacture of a compliant balloon characterized by heating to a temperature higher than a boundary temperature between a certain region and a rubber region to soften the polyurethane resin to expand the parison, contacting and pressing the balloon mold Method. 2. After the parison is stretched 1.4 to 1.8 times, the mold temperature is set to a temperature at least 35 ° C. higher than the boundary temperature between the region where the polyurethane resin is in the glass state and the region where it is in the rubber state. The method for producing a compliant balloon according to claim 1, wherein the compliant balloon is molded. 3. After stretching the parison by a factor of 1.8 to 3.5, the mold temperature is equal to or higher than the boundary temperature between the region where the polyurethane resin is in the glass state and the region where the polyurethane resin is in the rubber state, and at the highest, the boundary temperature. The method for producing a compliant balloon according to claim 1, wherein the molding is performed at a temperature not exceeding + 35 ° C.