JP2003062081A - Balloon for catheter and method of manufacturing it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a balloon for a catheter and a method of advantageously manufacturing it so as to advantageously accomplish both superior dilatability and crossability when inserted through a stenosed site and the like of various tubular organs of a human body. SOLUTION: The balloon for a catheter is composed of a polymer material having regions capable of crystallization and is structured such that the degree of crystallization in the outer surface is higher than that in the inner surface by more than 10% and that the orientation degree gradually increases from the inner surface toward the outer surface.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a balloon for a catheter and a method for manufacturing the balloon, and more particularly, to expand / contract a catheter inserted into a tubular organ of a human body in order to dilate a stenosis portion of the tubular organ. The present invention relates to a catheter balloon attached to a catheter and an advantageous method for manufacturing such a catheter balloon.

[0002]

BACKGROUND ART Conventionally, as a medical instrument to be inserted into a tubular organ of a human body such as a blood vessel, a digestive tract, a ureter, a trachea, a bile duct, or other body cavity or tissue for treatment or examination,
A catheter has been used, and in recent years, a balloon catheter having a balloon attached to the distal end of the catheter so as to be expandable / contractible has been used, for example, for treating myocardial infarction and angina. ing.

That is, as is well known, myocardial infarction and angina occur due to a decrease in blood flow to the myocardium due to the formation of a stenosis in the coronary artery of the heart. As one of the safe and effective methods for treating such myocardial infarction and angina without performing bypass surgery, a balloon catheter is inserted into the coronary artery of the heart in a deflated state and the stenosis thereof is performed. In recent years, a method of improving blood flow to the myocardium by allowing the balloon to expand (inflate) and expand the stenotic portion to reach a portion, so-called PTCA (coronary angioplasty), is commonly used in recent years. It is being done.

By the way, in the balloon of the balloon catheter used for such a treatment of PTCA and the like, the expansion performance capable of sufficiently expanding the narrowed portion of the relatively hard blood vessel and the entire balloon in the narrowed portion which bends in places. The distal end portion of the balloon is required to have a passing performance capable of smoothly passing (passing) while bending along the narrowed portion so that the balloon can be positioned. Among them, in order to improve the expansion performance, it is desirable to form the balloon with a hard material that exhibits high pressure resistance, while on the other hand, to improve the passage performance, easy flexibility and excellent flexibility are required. Since it is advantageous to form the balloon with a material that has this, it is extremely difficult to achieve both expansion performance and passage performance by simply selecting the material. It was difficult.

Under such circumstances, in Japanese Patent Laid-Open No. 9-164191 and Japanese Patent Laid-Open No. 9-506008, at least one surface of a base material layer made of a high-strength polymer or a non-flexible polymer material for a structure is used. It has been clarified that a balloon for a catheter is formed by integrally laminating a coating layer made of a flexible polymer, a thermoplastic elastomer, or the like, which is softer than the base material layer. In such a multi-layered catheter balloon, in the base material layer made of a high-strength polymer or a non-flexible polymer material for a structure, the expansion performance based on high compressive strength can be improved. In a coating layer made of a flexible polymer, a thermoplastic elastomer or the like, the passage performance derived from flexibility is improved, but in reality, the hardness of the balloon surface is simply increased by forming the coating layer. It was not possible to sufficiently realize the flexural rigidity required for improving the passing performance only by lowering it, and therefore it was not possible to obtain the expected effect of improving the passing performance. Of.

Moreover, since the catheter balloons disclosed in the above two publications have a multi-layered structure, it is unavoidable that the wall thickness increases.
Therefore, in order to smoothly pass through the narrowed portion, the thinning of the catheter balloon, which is desired in addition to flexibility, cannot be realized at all. Further, even when a balloon is manufactured by a known blow molding, since the parison that gives the target balloon has to have a multi-layer structure, the forming process of such a parison becomes inevitably complicated. Therefore, there is a problem in workability and cost efficiency in the manufacturing process of the balloon, and further, there is a possibility of causing a problem of peeling between the multiple layers in the parison and the balloon.

In Japanese Patent Laid-Open No. 192408/1993, blow molding is performed on a parison made of a flexible resin material while giving a temperature gradient that decreases from the inner surface portion to the outer surface portion. Discloses a method for producing a balloon in which the outer surface portion is oriented more than the inner surface portion and a higher tensile strength is imparted. However, when manufacturing a balloon for a catheter by such a method, in practice, it was extremely difficult to give a desired temperature gradient to the parison,
Therefore, in the manufactured balloon, sufficient expansion performance could not be stably obtained.

Further, Japanese Patent Laid-Open No. 2000-271209 discloses a balloon for a catheter, which is provided with pressure resistance and flexibility by controlling the crystallinity within a predetermined range. However, even with such a balloon, it can be said that the passage performance based on flexibility can be sufficiently exhibited,
It was hard to say.

[0009]

The present invention has been made in view of the circumstances as described above, and the first problem to be solved by the present invention is to increase the pressure resistance and the pressure resistance without increasing the wall thickness. Flexibility that is easy to bend can be sufficiently enhanced together, and when it is attached to a catheter and inserted into, for example, a stenotic portion of various tubular organs of the human body, both expansion performance and passage performance, It is an object of the present invention to provide an improved structure of a catheter balloon which can be very effectively and sufficiently exerted. Further, in the present invention, it is a second problem to be solved to provide a method for producing such a catheter balloon advantageously.

[0010]

SOLUTION: As a result of earnest and repeated studies by the present inventors to solve the first and second technical problems as described above, in a balloon having a single layer structure, simply,
In addition to increasing the degree of orientation of the outer surface portion more than that of the inner surface portion, at the same time, increasing the crystallinity of the outer surface portion to a certain size or more than the crystallinity of the inner surface portion causes bending in the inner surface portion. It has been found that, while ensuring easy flexibility, it becomes possible to exert excellent pressure resistance on the outer surface portion, and a balloon having such excellent characteristics can be used for a parison that gives the balloon. It was also found that the parison can be easily obtained by stretching the parison in the axial direction by drawing using a drawing die prior to blow molding.

That is, the present invention has been completed on the basis of such findings, and the gist of the invention is as follows.
In a balloon that is attached to a catheter so as to be expandable / contractible, the balloon is made of a polymer material having a crystallizable region, and the crystallinity of the outer surface portion is greater than that of the inner surface portion by 10% or more and is oriented. The catheter balloon is characterized in that the degree is gradually increased from the inner surface to the outer surface.

In such a balloon for a catheter according to the present invention, the degree of orientation is gradually increased from the inner surface to the outer surface of the balloon wall, so that the degree of orientation of the outer surface portion is higher than that of the inner surface portion. It is advantageously increased, and the crystallinity of the outer surface of the balloon wall is sufficiently higher than the crystallinity of the inner surface by 10% or more. Even if there is, flexibility that can be easily bent can be ensured in the inner surface portion, and excellent pressure resistance strength can be exhibited in the outer surface portion.

Therefore, in the catheter balloon according to the present invention as described above, both the pressure resistance and the flexibility for easy bending can be sufficiently enhanced while realizing the thinning by the single layer structure, Thus, when it is attached to a catheter and inserted into a narrowed portion of various tubular organs, both the expansion performance and the passage performance can be extremely effectively and sufficiently exhibited.

In addition, in the catheter balloon according to the present invention, as described above, when it is attached to the catheter and inserted into a narrowed portion of various tubular organs of the human body, excellent expansion performance and passage performance are exhibited. Therefore, for example, damage to the blood vessel wall or the like due to the destruction of the balloon during the medical work performed by expanding the narrowed portion of the tubular organ such as the blood vessel such as PTCA can be advantageously avoided, and the safety of medical work Not only can effectively increase the resistance of the blood vessel or the like when passing through the narrowed portion of the tubular organ such as a blood vessel, but also effectively improve the workability in medical work. It is possible to insert the balloon into the deep part of the stenosis.

Further, in the balloon for a catheter according to the present invention, since the flexibility for easy bending can be sufficiently enhanced, the bulk in the contracted state can be made smaller, and the rewrapping property ( The contraction performance from the expanded state) can be advantageously enhanced so that when the stricture part of a tubular organ such as a blood vessel is reached, expanded, and then contracted, the stenosis is extracted. Not only the portion but also the portion other than the narrowed portion can be passed more smoothly, and as a result, the workability in the medical work as described above can be enhanced more effectively.

According to one of the preferred embodiments of the catheter balloon according to the present invention, the polymer material having the crystallizable region is crystallized with respect to the thermoplastic elastomer having the crystallizable region. Can be a nucleating agent,
30% by weight of a crystalline polymer having a crystallizable region
It is composed of a composition prepared by mixing in the following proportions.

In the catheter balloon having such a structure, while maintaining a high degree of flexibility of the thermoplastic elastomer, the crystallizable region of the thermoplastic elastomer accompanying the addition of the crystalline polymer as the crystal nucleating agent is maintained. Increase,
By the crystallinity of such a crystalline polymer and the function as a crystal nucleus, the crystallinity of the thermoplastic elastomer can be more highly extracted, and excellent pressure resistance can be realized, and as a result, Both the compressive strength and the flexibility that can be easily bent can be enhanced more advantageously, and at the time of insertion into a narrowed portion of a tubular organ such as a blood vessel, the expansion performance and the passage performance are at a higher level. It can be demonstrated.

According to another advantageous embodiment of the catheter balloon according to the present invention, the polymer material having the crystallizable region imparts slidability to at least the outer surface portion. The fluidity-imparting material is contained at a ratio of 5% by weight or less. By adopting such a configuration, when attached to a catheter and inserted into a narrowed portion of a tubular organ such as a blood vessel, excellent slidability can be exerted on the inner surface of the narrowed portion. Therefore, more sufficient passage performance can be exhibited.

In order to solve the above-mentioned second problem, the present invention provides a method for manufacturing a balloon which is attached to a catheter so as to be expandable / contractible,
(A) preparing a parison made of a polymer material having a crystallizable region, and (b) using a drawing die having a die hole with an inner diameter smaller than the outer diameter of the prepared parison, Through the die hole of the die,
A step of pre-processing the parison, which comprises drawing the parison in the axial direction while stretching the parison; and (c) a step of blow-molding the pre-processed parison to form an intended balloon. A method for manufacturing a characteristic balloon for a catheter is also the gist thereof.

That is, in such a method for manufacturing a balloon for a catheter according to the present invention, prior to the blow molding of a parison formed of a polymer material having a crystallizable region, which gives a target balloon, Since the parison is pre-processed by drawing the parison in the axial direction by drawing using a drawing die, it has a crystallizable region as described above. In addition to being made of a polymer material, the crystallinity of the outer surface portion of the balloon wall is 10% or more greater than the crystallinity of the inner surface portion, and the degree of orientation is
The balloon configured to gradually increase from the inner surface to the outer surface can be easily and reliably formed.

Therefore, according to the method for producing a balloon for a catheter in accordance with the present invention, it is possible to advantageously increase both the pressure resistance and the flexibility of easy bending while realizing the thinning by the single layer structure. Therefore, when attached to a catheter and inserted into a stenotic portion of a tubular organ such as a blood vessel, a catheter balloon capable of effectively and sufficiently exhibiting both expansion performance and passage performance is extremely advantageous. Can be manufactured.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, in order to more specifically clarify the present invention, the configurations of a catheter balloon and a method for producing the same according to the present invention will be described in detail with reference to the drawings. .

First, FIGS. 1 and 2 show an example of a catheter balloon having a structure according to the present invention in a longitudinal sectional shape and a transverse sectional shape under a state in which it is attached to a catheter and expanded or inflated. And are respectively shown schematically. As is apparent from FIGS. 1 and 2, the catheter balloon 10 of the present embodiment has an axially intermediate portion which is an expanded or inflatable bulge portion 12, while both end portions thereof are mutually The mounting portions 14 and 16 have different outer diameters.

And in such a balloon 10,
As shown by the solid lines in FIGS. 1 and 2, when the expanded portion 12 is expanded or inflated, the expanded portion 12 has a larger diameter than the two mounting portions 14 and 16 and has a substantially stepped cylindrical overall shape. 1 and 2, and as shown by the chain double-dashed line in FIGS. 1 and 2, before the expansion of such an enlarged portion 12, the enlarged portion 12 is closed when the umbrella is closed and folded. With the same shape, the outer shape formed by folding and the entire exposed surface to the outside in the folded enlarged portion 12 has a maximum outer diameter smaller than the outer diameter of the large-diameter mounting portion 16. , And has a substantially cylindrical shape. Further, here, the maximum outer diameter (dimension indicated by m in FIG. 2) in the enlarged portion 12 that is folded as described above and has a substantially cylindrical outer shape and the diameter that gives the maximum outer diameter are set. The dimension of the diameters that are positioned orthogonally (n in FIG.
And the ratio value (m / n) with respect to the vertical outer diameter will be approximately 1.

Further, in the balloon 10 as described above, the inner shaft 20 composed of a small-diameter tubular body is inserted into the outer shaft 18 made of a large-diameter tubular body as in the conventional case. It is adapted to be attached to the distal end of a catheter 22 having a double tube structure. That is, of the mounting portions 14 and 16 at both ends of the balloon 10,
With the distal end portion of the catheter 22 inserted from the mounting portion 14 side having a large diameter, the mounting portion 14 having a large diameter is attached to the distal end portion of the outer shaft 18 of the catheter 22.
An inner shaft 20 is attached airtightly, and a small-diameter mounting portion 16 located at the end opposite to the large-diameter mounting portion 14 is protruded from the distal end portion of the outer shaft 18 of the catheter 22. It is configured to be airtightly fixed to the tip portion.

Thus, in the balloon 10 according to the present embodiment, for example, the inner shaft 2 of the catheter 22 is attached to the tip end of the catheter 22.
While being guided by a guide wire (not shown) inserted through the inside of the catheter 0, it is inserted into a blood vessel such as a coronary artery in which a stenotic portion is formed and advanced so that the stenotic portion can be reached and positioned. It has become. Then, at that position, the outer shaft 1 of the catheter 22
An expansion liquid such as physiological saline solution supplied through the inner hole from the tip opening of 8 is fed into the balloon 10 to be filled therein, whereby the enlarged portion 12 is expanded or inflated, The swelling portion 12 is configured to be able to spread the narrowed portion, and under such a condition, the expansion liquid filled in the swelling portion 12 is discharged from the tip opening of the outer shaft 18. As a result, the enlarged portion 12 can be contracted. The catheter 22 is again guided by the guide wire under the contracted state of the bulging portion 12 and extracted from the blood vessel such as the coronary artery. However, the stenosis portion is expanded even after the catheter 22 is extracted. The state of being kept as it is will be maintained.

By the way, as described above, the catheter balloon 10 of this embodiment, which is attached to the catheter 22 so as to be expandable / contractible, has a single-layer structure, as is apparent from FIG. As a result, thinning can be advantageously realized. Here, according to the present invention, the thin balloon 10 is made of a polymer material having a crystallizable region, and the crystallinity of the outer surface portion is higher than that of the inner surface portion. It is configured to be larger than 10% and the degree of orientation gradually increases from the inner surface to the outer surface.

That is, in such a balloon 10, the crystallinity of the outer surface portion of the balloon wall is 10% or more higher than the crystallinity of the inner surface portion, and the degree of orientation is the inner surface of the balloon wall. Due to the synergistic effect of gradually increasing from the outer surface to the outer surface, despite having a thin wall, the inner surface portion has sufficient flexibility that can be easily bent, while the outer surface portion exhibits high pressure resistance. It can be done.

Moreover, since such a balloon 10 is thin and has sufficient flexibility in the inner surface portion, when the expanded portion 12 is contracted from the expanded state, it is not expanded yet. The state is relatively close to the folded state of. That is, in the conventional product, when the expanded portion 12 is contracted from the expanded state, it becomes a flat state regardless of the folded state before the expansion. Balloon 10 of the present embodiment
Is restored to a folded state before being expanded, that is, a folded state similar to a folded state of a rain umbrella, as shown by a chain double-dashed line in FIGS. 1 and 2, when contracted from the expanded state. Has become. As a result, here, even when the enlarged portion 12 contracts, the outer shape of the enlarged portion 12 has a maximum outer diameter smaller than the large-diameter mounting portion 14 (dimension indicated by m in FIG. 2). In addition, the ratio (m / n) of the ratio between the maximum outer diameter and the vertical outer diameter (dimension indicated by n in FIG. 2) becomes a value close to 1, so that it has a substantially cylindrical shape similar to that before the expansion. It is composed of

The method of measuring the respective crystallinities for obtaining the difference between the crystallinity of the outer surface and the crystallinity of the inner surface of the balloon wall of the balloon 10 is not limited in any way. Known methods of measuring crystallinity, such as density, X-ray diffraction, infrared absorption (IR), Raman spectrum, and nuclear magnetic resonance (NMR) spectrum, can be appropriately adopted. .

Further, the polymer material having a crystallizable region which constitutes such a balloon 10 is not particularly limited, and examples thereof include polyolefin, polyamide, polyurethane, polyester, polyolefin elastomer, polyamide elastomer, and the like. One of the various known materials such as polyurethane elastomer and polyester elastomer may be selected and used alone, or two or more of them may be used in a suitable mixing ratio. The composition obtained by combining the above is used to form the composition.

Among them, in the case of using a thermoplastic elastomer having a crystallizable region, on the other hand, when the thermoplastic elastomer itself has a crystallizable region and is added to the thermoplastic elastomer, a crystal nucleating agent is used. A composition obtained by blending a relatively high crystalline polymer that can be used in an amount of 30% by weight or less will be preferably used. Because, in such a composition, the high degree of flexibility of the thermoplastic elastomer can be effectively exerted, and at the same time,
Due to the increase of the crystallizable region of the thermoplastic elastomer accompanying the addition of the high molecular polymer as the crystal nucleating agent, and further, the high crystallinity of the high molecular polymer and the function as the crystal nucleating agent, the thermoplastic elastomer is increased. This is because the crystallinity of can be extracted to a higher degree and excellent pressure resistance can be realized. The crystalline high-molecular polymer is appropriately determined according to the type of thermoplastic elastomer. For example, when the thermoplastic elastomer is polyamide elastomer, nylon 12 or the like is used.
Further, for a thermoplastic elastomer having a crystallizable region, 30
In the case of blending in a proportion of more than wt%, further improvement of the crystallinity of the thermoplastic elastomer cannot be expected, and on the contrary, the flexibility of the thermoplastic elastomer will be impaired. The blending amount is determined so that the content is 30% by weight or less based on the whole composition.

Further, as described above, the polymer material having the crystallizable region is advantageous because the balloon 10 can be smoothly moved in a blood vessel such as a coronary artery in which a stenotic portion is formed. Is a slidability imparting material that imparts slidability to at least the outer surface portion of the balloon 10.
The target balloon 10 is constituted by containing 5% by weight or less. As the slidability imparting material, for example, a low friction coefficient material such as silicone oil or polytetrafluoroethylene (PTFE) is used. Further, even if such a slidability-imparting material is contained in a proportion of more than 5% by weight with respect to the polymer material forming the balloon 10 and having a crystallizable region, the outer surface portion of the balloon 10 No further improvement in slidability was observed, and therefore the content of the slidability-imparting material was 5 in order to suppress wasteful use of the material.
It is said to be less than weight%.

By the way, the catheter balloon 10 having such a structure is advantageously manufactured by utilizing a well-known blow molding method. In that case, for example, the following is performed. , That work will proceed.

That is, first, as shown in FIG. 3, using a known extruder or the like (not shown), the nozzle 24 attached to the tip of the extruder constitutes the balloon 10, and a predetermined crystallization is possible. After extruding the polymer material having a region in a molten state, it is immediately cooled with cold water to form the parison 26 made of such a material.

Then, as shown in FIG. 4, a drawing die 30 having a die hole 28 having an inner diameter smaller than the outer diameter of the previously extruded parison 26 by a predetermined dimension is used.
The parison 26 is pulled out in the axial direction through the die hole 28 of the pulling die 30. In the drawing step, for example, the drawing die 30 is used after being heated to about 80 ° C., and the core metal having an outer diameter slightly smaller than the inner diameter of the parison 26 in the inner hole of the parison 26. A method such as pulling out under the condition that 32 is inserted will be adopted.

Thus, in the drawing step, the parison 26 is preliminarily processed by thinning the parison 26 and stretching the parison 26 in the axial direction so that the crystallinity of the outer surface portion of the wall of the parison 26 is increased. The crystallinity is increased more than the crystallinity of the inner surface, and the degree of orientation is gradually increased from the inner surface to the outer surface.

The inner diameter of the die hole 28 of the drawing die 30 used in the drawing process of the parison 26 is as follows.
It will be appropriately determined depending on the outer diameter of the parison 26. That is, the difference between the crystallinity of the outer surface portion and the crystallinity of the inner surface portion of the target balloon wall of the balloon 10 is determined by the crystallinity of the outer surface portion and the crystallinity of the inner surface portion of the wall portion of the parison 26 after the drawing process. The crystallinity of the outer surface of the target balloon wall of the target balloon 10 is more than that of the inner surface of the balloon 10 because it is derived from the difference in crystallinity.
% So that the crystallinity of the outer surface portion of the parison 26 after the drawing process is greater than the crystallinity of the inner surface portion of the parison 26 in accordance with the outer diameter of the parison 26. The inner diameter of the die hole 28 is determined.

After that, as shown in FIG. 5, the parison 26 preliminarily processed by the above-mentioned drawing corresponds to the target balloon 10 formed in the blow molding mold 34 in the mold closed state. It is placed in a shaped cavity 36. At this time, the ends of the parison 26 on both sides in the axial direction are hermetically sealed by the mold matching parts of the blow molding mold 34.

Subsequently, as shown in FIG. 6, after inserting the air nozzle 38 into the sealing portion on one axial side of the parison 26, the parison 2 is passed through this air nozzle 38.
By blowing air into the parison 26 to expand the parison 26, an intermediate compact 40 having a shape corresponding to the inner surface shape of the cavity 36 is obtained. After that, although not shown, the blow molding die 34 is opened to separate the intermediate molding body 40 from the blow molding die 34, and then both axial end portions of the intermediate molding body 40 are removed. The unnecessary portion of is cut to obtain the desired catheter balloon 10 as shown in FIG.

As described above, in the present embodiment, the parison 2 formed by using the polymer material having the crystallizable region is used.
6 is preliminarily processed by simply drawing the drawing die 30 through a die hole 28 having a predetermined inner diameter, and then the parison 26 subjected to the preprocessing is subjected to normal blow molding. The obtained balloon 10 has a single layer structure made of a polymer material having a crystallizable region, and the crystallinity of the outer surface portion is 10% or more larger than that of the inner surface portion. And the degree of orientation can be easily configured so as to gradually increase from the inner surface to the outer surface.

Therefore, according to the present embodiment as described above,
In the catheter balloon 10 in which the thinning due to the single layer structure can be advantageously realized, and the compressive strength and the flexibility for easy bending can be sufficiently enhanced, for example, the temperature of the parison 26 can be partially different. The catheter balloon 10 thus manufactured can be extremely easily manufactured without performing any troublesome and difficult operation, and the catheter balloon 10 thus manufactured is attached to the catheter 22 to a narrowed portion of a blood vessel such as a coronary artery. When inserted, both expansion performance and passage performance can be exerted extremely effectively and sufficiently, based on high pressure resistance and excellent flexibility that allows easy bending. is there.

In this embodiment, as described above, when the balloon 10 is attached to the catheter 22 and inserted into a narrowed portion of a blood vessel such as a coronary artery,
Since excellent expansion performance and passage performance can be exhibited, for example, it is advantageous that the balloon 10 is destroyed when it is expanded at the stenosis portion and the wall of a blood vessel such as a coronary artery is damaged. As a result, the safety of medical work involving the operation of inserting the balloon 10 into a blood vessel such as a coronary artery can be effectively enhanced. In addition, the resistance generated when the balloon 10 passes through a narrowed portion of a blood vessel such as a coronary artery can be advantageously made small, so that not only the workability in the medical work can be improved but also the deep portion of the narrowed portion can be obtained. Therefore, the balloon 10 can be made to reach smoothly.

Further, in this embodiment, since the balloon 10 is thin and has a high degree of flexibility, the outer shape of the enlarged portion 12 is large when the balloon 10 is deflated. Has a smaller maximum outer diameter (dimension indicated by m in FIG. 2) and a ratio value (m / n) between the maximum outer diameter and the vertical outer diameter (dimension indicated by n in FIG. 2). ) Is approximately 1, and the re-wrapping property (contraction performance from the expanded state) can be advantageously enhanced because it has a substantially cylindrical shape similar to that before expansion. As a result, when it is attached to the catheter 22 and is once expanded and then contracted at a narrowed portion in a blood vessel such as a coronary artery, when it is pulled out from the narrowed portion, not only the narrowed portion but also the narrowed portion is narrowed. Even in the parts other than the parts, the parts can be passed more smoothly, thereby
The workability in medical work involving the operation of inserting the balloon 10 into a blood vessel such as a coronary artery can be more effectively enhanced.

In the above embodiment, the parison 26 for providing the catheter balloon 10 is formed by extrusion molding. However, the parison 26 may be formed by a method other than extrusion molding such as injection molding. It is possible.

Needless to say, the overall shape of the catheter balloon 10 is not particularly limited to that shown in the above embodiment.

The specific construction of the present invention has been described above in detail, but this is merely an example, and the present invention is subject to various changes, modifications, improvements, etc. based on the knowledge of those skilled in the art. It is understood that the present invention can be carried out in a mode in which any of the following is added, and that all such embodiments are included in the scope of the present invention without departing from the spirit of the present invention. Should be.

In addition, representative examples will be shown below. However, the present invention should not be construed as being limited to the specific examples described above and the detailed description of the embodiments of the present invention. Needless to say.

[0049]

EXAMPLE First, as a polymer material having a crystallizable region which constitutes a target catheter balloon, 34
A polyamide elastomer having a flexural modulus of 0 MPa (polyether block amide: a copolymer of polyether that is a soft segment and polyamide that is a hard segment) and nylon 12 having a flexural modulus of 1470 MPa in a weight ratio of 9: A polymer material composed of a composition blended in a ratio of 1 was prepared. Then, using the prepared polymer material, extrusion molding was performed using a known extruder to obtain an outer diameter of 0.97 mm and
A parison of predetermined length having an inner diameter of 60 mm was molded. The crystallinity of the inner surface portion and the crystallinity of the outer surface portion of the thus-formed parison were determined by the following formula (1) by a known surface reflection infrared absorption method. The degree was 1.617, and the crystallinity of the outer surface portion was 1.636.

Crystallinity = peak area of amide I / peak area of amide II (1) [wherein amide I shows a peak at a wavelength of 1490 to 1590 cm ⁻¹ , and amide II is 1590 to 16
It shows a peak at a wavelength of 90 cm ^-1 . ]

Then, using a drawing die having a die hole having an inner diameter of 0.90 mm and a core metal having an outer diameter of 0.59 mm and a circular cross section having a predetermined length, the core metal is molded as described above. The drawing die was heated to 80 ° C. while being inserted into the inner hole of the parison. Then, the parison having the cored bar inserted therein was axially pulled out through the die hole of the prepared drawing die to thin the parison and stretch it in the axial direction.

Here, the crystallinity of the inner surface portion and the crystallinity of the outer surface portion of the wall portion of the parison after the stretching process are determined in the same manner as when the respective crystallinities of the parison were obtained before the stretching process. The crystallinity of the inner surface part was 1.673, and the crystallinity of the outer surface part was 1.840. The crystallinity of the outer surface part was crystallized by the stretching process. It was found to be increased by a greater amount compared to the degree.

Next, the stretched parison was housed in a cavity formed in a blow molding die having a known structure and having a shape corresponding to the intended balloon, and then, in the same manner as in the conventional case. The target balloon (Example) was obtained by blowing air into the parison. The outer diameter of the balloon thus obtained was 3.0 mm, and the thickness was 23 μm.

On the other hand, apart from the balloon of the embodiment obtained as described above, the same material as the polymer material having the crystallizable region, which constitutes the balloon of the embodiment, is used,
0.86 was obtained by extrusion molding using a known extruder.
A parison of a predetermined length having an outer diameter of mm and an inner diameter of 0.52 mm was molded. The crystallinity of the inner surface portion and the crystallinity of the outer surface portion of the thus-formed parison were determined in the same manner as in the case of determining the respective crystallinity of the parison that gives the balloon of the above example, the inner surface. Part has a crystallinity of 1.602, and the outer surface has a crystallinity of 1.61.
It was 5.

Then, for comparison, the parison thus formed was formed in the blow molding die having a known structure as it was without performing any stretching process as described above. Then, the target balloon (comparative example) was obtained by containing it in a cavity having a shape corresponding to the target balloon and blowing air into the parison in the same manner as when molding the balloon of the example. The outer diameter of the balloon thus obtained is 3.0.
mm, and the thickness was 24 μm.

Next, the crystallinity of the inner surface portion and the crystallinity of the outer surface portion of the wall portions of the two types of balloons of the example balloons and the comparative example balloons obtained as described above are respectively calculated as the parison. In the same way as when determining the crystallinity of
From the obtained respective values, the ratio (percentage) of the difference between the crystallinity of the outer surface portion and the crystallinity of the inner surface portion with respect to the crystallinity of the inner surface portion, in other words, the outer surface portion The percentage (percentage) of the crystallinity of the above is larger than that of the inner surface portion of each of the two types of balloons. The results are also shown in Table 1 below. In Table 1 below, the ratio (percentage) of the difference between the crystallinity of the outer surface portion and the crystallinity of the inner surface portion with respect to the crystallinity of the inner surface portion is shown simply as a ratio.

Further, the compressive strength of these two types of balloons (Example and Comparative Example) was measured by a known method.
Each was measured. The results are also shown in Table 1 below.

In order to check the insertion resistance of each of the balloons of the examples and the comparative example, that is, the resistance caused by the contact with the wall surfaces of the balloons when inserted into various tubular organs, etc., first, Is 1.5 mm and length is 10
A 0 mm polytetrafluoroethylene tube
A test tube was prepared which was deformed into a U shape having a curved portion with a radius of 10 mm. Further, on the other hand, an inner shaft made of high-density polyethylene having an outer diameter of 0.60 mm and an inner diameter of 0.43 mm is connected to each of the two types of balloons (Example and Comparative Example), which is well known. Wrapping process was applied. After that, the inner shafts were connected, and two types of balloons subjected to lapping (Examples and Comparative Examples) were inserted into the prepared test tubes and moved forward at the same speed. Then, the insertion resistance value of each balloon at that time was measured in the same manner as in the prior art. The results are also shown in Table 1 below.

Further, in order to examine the respective wrap properties of the balloons of the examples and the comparative example, each balloon was expanded at a pressure of 14.19 × 10 ⁵ Pa for 60 seconds, and then a negative pressure was applied. The deflated, and the maximum outer diameter of each balloon in the deflated state and the vertical outer diameter (that is, in the outer shape of the balloon in the deflated state, so as to be orthogonal to the diameter giving the maximum outer diameter). The dimension of the diameter located) and was measured respectively. Further, the value of the ratio of the measured maximum outer diameter to the vertical outer diameter (maximum outer diameter / vertical outer diameter) and roundness were calculated. The measured values and calculated values are also shown in Table 1 below.

[0060]

[Table 1]

As is clear from the results shown in Table 1, the balloons of the examples obtained by subjecting the parison to stretch processing and then blow molding the parison according to the method of the present invention have the outer surface of the wall portion. Crystallinity of
While the crystallinity of the inner surface portion is 17% higher, the balloon of the comparative example obtained by the same method as the conventional one has the crystallinity of the outer surface portion of the wall portion is larger than that of the inner surface portion. Only about 5% larger than the degree of chemical conversion. Then, in the balloon of such an example and the balloon of the comparative example, when the respective pressure resistance and insertion resistance are compared, the balloon of the example has a higher pressure resistance than the balloon of the comparative example, and It is recognized that the insertion resistance is sufficiently small. Furthermore, when comparing the outer diameters of the balloons of the examples and the balloons of the comparative examples in the respective deflated states, the balloons of the examples have a smaller maximum outer diameter and a smaller vertical outer diameter than the balloons of the comparative examples. It can be seen that the roundness is large and thus the roundness is close to 1. That is, from these, when compared with the balloon of the comparative example, the balloon of the example, when attached to a catheter and inserted into a stenosis portion of a blood vessel such as a coronary artery, has both expansion performance and passage performance. It can be clearly recognized that better properties can be exerted in performance.

Next, in the composition suitably used as the polymer material having the crystallizable region, which constitutes the balloon for catheter according to the present invention, the thermoplastic elastomer having the crystallizable region and the crystal nucleating agent can be used. The following tests were carried out to find out what the desirable range of the blending ratio with the crystalline polymer having the crystallizable region is.

That is, first, as a thermoplastic elastomer having a crystallizable region, the heat of crystallization is 38.7 J /
While preparing a predetermined amount of polyamide elastomer (the same as that used in obtaining the balloon of the above-mentioned example) of g, the crystalline polymer having a crystallizable region that can serve as a crystal nucleating agent is crystallized. The heat of chemical conversion is 54.4 J /
A predetermined amount of nylon 12 (the same as that used to obtain the balloons of the above examples), which is g, was prepared.
The amount of heat of crystallization of each of the materials prepared as the blending components was measured by using a differential scanning calorimeter (DSC).
It was determined by cooling 10 mg of the sample from the molten state at −2 ° C./min and measuring the amount of heat required for crystallization.

Next, the prepared polyamide elastomer and nylon 12 were blended in a weight ratio of 9: 1 to obtain a composition 1, and these were mixed in a weight ratio of 7: 7.
3 to obtain a composition 2, and
Blend them in a weight ratio of 5: 5,
Composition 3 was obtained. Then, the heat of crystallization of each of the three kinds of compositions (compositions 1 to 3) thus obtained is calculated based on the blending ratio to obtain a calculated value, while the materials prepared as blending components The actual measurement value using DSC was obtained in the same manner as when the heat of crystallization of was measured. Also,
The ratios (percentages) of the calculated values obtained by subtracting the calculated values from the calculated values were calculated. The results are also shown in Table 2 below.

[0065]

[Table 2]

As is clear from the results shown in Table 2, the polyamide elastomer, which is a thermoplastic elastomer having a crystallizable region, is blended with nylon 12, which is a crystalline polymer having a crystallizable region that can serve as a crystal nucleating agent. The three types of compositions (composition 1 to
In 3), in all cases, the measured value of the heat of crystallization exceeded the calculated value, and the amount of increase was about 8% in the composition 1 and about 6% in the composition 2, In the case of 3, it is about 2%. From this fact, the crystallinity of the polyamide elastomer can be sufficiently derived by blending the nylon 12 with the polyamide elastomer, and in particular, for the polyamide elastomer, the nylon 12 is added to the total amount of the composition. On the other hand, it can be confirmed that the crystallinity of the polyamide elastomer can be further enhanced by blending it in a proportion of about 30% by weight or less.

Incidentally, the 3 obtained as described above
Using the compositions of the types, the polyamide elastomers prepared to obtain the compositions, and the nylon 12, five types of balloons having different constituent materials are manufactured according to the method of the present invention. The insertion resistance value of the balloon was measured by the same method as the method for measuring the insertion resistance value of the above-mentioned example. As a result, the insertion resistance value of the balloon composed of the composition 1 was 274 mN, and the insertion resistance value of the composition 2 was composed. The balloon has an insertion resistance value of 294 mN, the balloon made of the composition 3 has an insertion resistance value of 363 mN, and the balloon made of only the polyamide elastomer has an insertion resistance value of 245 mN and made of nylon 12 only. The insertion resistance value of the prepared balloon was 412 mN. From this, nylon 12 is added to polyamide elastomer.
It can be confirmed that a low insertion resistance value can be advantageously ensured by blending in a proportion of about 30% by weight or less based on the total amount of the composition.

[0068]

As is apparent from the above description, in the catheter balloon according to the present invention, both the pressure resistance and the flexibility for easy bending are realized while realizing the thinning due to the single layer structure. It can be sufficiently enhanced, and when it is attached to a catheter and inserted into a stenotic portion of various tubular organs, etc., both expansion performance and passage performance can be extremely effectively and sufficiently exhibited. .

According to the method for producing a catheter balloon according to the present invention, a catheter balloon exhibiting such excellent characteristics can be produced extremely advantageously.

[Brief description of drawings]

FIG. 1 shows an example of a catheter balloon according to the present invention,
It is a longitudinal cross-sectional explanatory view shown under the state attached to the catheter.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is an explanatory view showing an example of a process for producing a catheter balloon according to the method of the present invention, showing a state in which a parison for giving the catheter balloon is being molded.

FIG. 4 is an explanatory view showing another example of steps in manufacturing a catheter balloon according to the method of the present invention, showing a state in which preparatory processing by stretching is performed on a parison that gives the catheter balloon. There is.

FIG. 5 is an explanatory view showing still another example of the process of manufacturing a balloon for a catheter according to the method of the present invention, showing a state in which a preprocessed parison is housed in a blow molding die.

FIG. 6 is an explanatory view showing another example of the process of manufacturing a balloon for a catheter according to the method of the present invention, in which air is blown into the parison housed in the blow molding die to obtain the object. The state which has formed the balloon is shown.

[Explanation of symbols]

10 Balloon for Catheter 12 Enlarged Part 14, 16 Attachment Part 22 Catheter 26 Parison 28 Die Hole 30 Drawing Die 34 Blow Molding Die 36 Cavity 40 Intermediate Molded Body

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shigenori Iwamuro             1703 Wakitacho, Moriyama-ku, Nagoya-shi, Aichi Morning             Nichi Intec Co., Ltd. F-term (reference) 4C081 AC10 CB01 EA02 EA05                 4C167 AA07 BB05 BB26 BB28 BB38                       BB39 CC09 DD01 FF01 GG31                       GG36 GG37 HH01

Claims (4)

[Claims] 1. A balloon, which is attached to a catheter so as to be expandable / contractible, is made of a polymer material having a crystallizable region, and the crystallinity of the outer surface portion is 10 more than that of the inner surface portion. % Or more and the degree of orientation is
A catheter balloon, which is configured to gradually increase from an inner surface to an outer surface. 2. The crystalline material having a crystallizable region, wherein the polymer material having a crystallizable region is 30% by weight of a crystalline polymer having a crystallizable region, which can serve as a crystal nucleating agent for a thermoplastic elastomer having a crystallizable region. The catheter balloon according to claim 1, wherein the balloon is composed of a composition blended in the following proportions. 3. The polymer material having the crystallizable region contains at least 5% by weight of a slidability imparting material that imparts slidability to at least the outer surface portion. The balloon for a catheter according to claim 1 or 2. 4. A method of manufacturing a balloon that is expandably / contractably attached to a catheter, comprising: providing a parison made of a polymer material having a crystallizable region; and preparing a parison outside the prepared parison. A pre-processing step of a parison, which comprises using a drawing die having a die hole having an inner diameter smaller than the diameter, and drawing the parison axially while drawing the parison through the die hole of the drawing die, and the pre-processing. Blow molding the parison thus formed to form an intended balloon.