JP6134154B2 - Balloon for balloon catheter - Google Patents

Description

  The present invention relates to a balloon catheter used for a balloon catheter used in an operation for the purpose of expanding a living body lumen.

  Conventionally, percutaneous angioplasty (PTA: Percutaneous Transluminal Angioplasty or PTCA) expands and treats stenosis or occlusion of vascular lumen and restores blood flow such as coronary arteries and peripheral blood vessels. Widely used for improvement. A balloon catheter used for percutaneous angioplasty is formed by joining a balloon that can be inflated and deflated by adjusting internal pressure to the tip of a shaft, and a guide wire is inserted into the shaft. A structure in which a cavity (guide wire lumen) and a lumen (inflation lumen) for supplying a pressure fluid for adjusting balloon internal pressure are provided along the longitudinal direction of the shaft.

  A general surgical example of PTCA using such a balloon catheter is as follows. First, a guide catheter is inserted from a puncture site such as a femoral artery, brachial artery, or radial artery, and the distal end thereof is disposed at the entrance of the coronary artery via the aorta. Next, the guide wire inserted through the guide wire lumen is advanced beyond the stenosis site of the coronary artery, and a balloon catheter is inserted along the guide wire to match the balloon with the stenosis. Next, using a device such as an inflator, a pressure fluid is supplied to the balloon via the inflation lumen, and the balloon is inflated to expand the stenosis. After dilatation treatment of the stenosis, PTCA is terminated by retracting the balloon under reduced pressure and removing it from the body. PTA is also performed in the same manner as PTCA on the lesioned part of the lower limb artery.

  In recent years, there is a tendency for balloon catheters to be applicable to highly difficult lesions with stenosis and bending, and the balloon can pass smoothly through the lesions. There is a need for a PTCA balloon catheter and a PTA balloon catheter having permeability.

One of the factors that greatly contribute to the passage of the balloon catheter is the folding size of the balloon portion. For this reason, the diameter of the balloon part is reduced by devising a folding method at the time of producing the catheter. In general, the balloon portion of a balloon catheter is folded by wrapping the balloon around the inner shaft at the manufacturing stage to reduce the folding dimension as much as possible. It is desirable to be able to fold around the catheter shaft and reduce the diameter. This is because the catheter used to expand the lesion may be used again to treat other lesions. Further, it is desirable to reduce the diameter as much as possible when taking it out of the body. In particular, when the catheter has passed through the stent strut, it is necessary to remove the catheter from the stent strut after the treatment. Therefore, the balloon portion can be more safely removed if it is folded to a small diameter.

  For convenience, in the balloon catheter manufacturing process, the device is used to “wrap” the balloon by external force, and after the wrapped balloon is expanded, the pressure fluid is removed to spontaneously contract, Folding the balloon is called “relapping”.

  In addition, a convex portion at the time of wrapping, that is, a section protruding outward from the inside of the balloon in a cross section perpendicular to the long axis direction of the balloon is a “wing portion”, and there are a plurality of concave portions, that is, the wing portion. A portion between the adjacent wings is referred to as a “groove”. Moreover, the shape at the time of wrapping is expressed using the number of wings. For example, in the case of FIG. 8, there are four blades.

  The passage performance of the balloon catheter to the stenosis is called “cross performance”. In particular, the passage performance in the wrapped state, that is, the passage performance at the first use is “first cross performance”, and the balloon is expanded in the stenosis. After that, the performance of passing the balloon catheter through the same or different stenosis in the rewrapped and rewrapped state is referred to as “recross performance”.

  Conventionally, various balloons that have been brazed with a wrapping shape and methods for manufacturing the same have been proposed for the purpose of stabilizing the wrapping shape and reducing the diameter.

  For example, Patent Document 1 discloses a method in which a wall thickness distribution is provided in a cross section perpendicular to the major axis direction of a balloon (hereinafter referred to as a balloon cross section), and balloon wrapping is controlled by a difference in rigidity caused by the difference in film thickness. It is disclosed. However, when forming a thickness wrinkle while achieving the pressure resistance of the balloon after forming the thickness distribution on the balloon cross section, it is necessary to set the thickness of the thin portion of the balloon in accordance with the required pressure resistance. Along with this, the thickness of the thick part has to be increased, and the overall thickness increases, so that the wrapping and rewrapping dimensions tend to increase. If the balloon wrapping and rewrapping dimensions are large in the balloon catheter, there is a problem in the cross performance of the balloon catheter that the first cross performance and the recross performance are impaired.

  In addition, in order to provide a thickness difference in the balloon state, an extreme thickness difference must be provided in advance in the balloon tube before blow molding, and the production of such a balloon tube is very difficult and the production yield is low. However, it is difficult to manufacture a balloon having a stable quality such that the final balloon has a different film thickness in order to form a balloon by blow-molding a balloon tube having an extreme thickness difference.

  Patent Document 2 discloses a balloon formed into a shape defined by at least three flutes extending along the longitudinal direction of the balloon and alternating wings.

  Patent Document 3 discloses a scroll shape in which at least a plurality of longitudinal grooves continuous in the long axis direction of the balloon and the same number of wings corresponding to the longitudinal grooves are formed in advance by a mold, and are formed by concave grooves and ridges. A balloon shaped into a shape having wings and longitudinal grooves corresponding to a cross section is disclosed. However, when the groove and the protrusion are formed as in Patent Document 2 or 3, stable control of the wrapping shape can be realized, but the shape of the balloon cross section at the time of expansion is not substantially circular, which is sufficient in clinical practice. There was a problem that it could not be obtained. In addition, the balloon mold used for shaping has a very complicated shape, and much time is wasted on product development, and there is room for improvement in that the manufacturing cost becomes very high.

  Patent Document 4 discloses a balloon in which at least three ribs are formed on the inner surface (thickness direction) of the balloon cross section, and a method for manufacturing the same. It is disclosed that a tube having ribs on the inner surface can be produced by extrusion forming a tube having ribs on the inner surface and then blow molding. However, as in Patent Document 1, since the thickness of the thin portion of the balloon is set in accordance with the required pressure resistance, the wrapping and rewrapping dimensions tend to increase, and as a result, the first cross performance and recross performance of the balloon catheter. There was a problem in that it decreased.

  Patent Document 5 discloses a balloon having the same number of two types of lamellae (A and B) having different elasticity on the circumference of the balloon cross section along the balloon major axis direction and a manufacturing method thereof. As a specific manufacturing method, there are a method of forming a balloon tube by coextrusion of materials having different elasticity, and a method of forming a lamellar portion having different elasticity by locally laminating a resin to only one lamella portion on the balloon. It is disclosed. However, when such a balloon tube is manufactured by coextrusion molding, the materials having different elasticity are extremely different in fluidity at the time of extrusion, so that the technical difficulty is very high in terms of providing stable dimensions. However, there were problems in practical use. Further, when trying to manufacture by coextrusion molding, two melt extruders are required, and there is a problem that the manufacturing cost becomes very high. Moreover, even if a balloon tube can be produced by coextrusion, it is difficult to produce a balloon by blow-molding the balloon tube due to the characteristic difference between different materials. When the balloon is formed of a different material, there are problems that the strength of the balloon is reduced due to stress concentration, a desired therapeutic effect cannot be obtained due to non-uniform expansion, and there is a high risk of damaging the blood vessel.

Japanese Patent Laid-Open No. 3-92173 JP-A-2-224766 JP 2003-62080 A Japanese National Publication No. 6-506848 European Patent Application No. 2072067

  In the conventional technology, the balloon cross-section produced is not deformed and is not substantially circular, and the film thickness and material of each balloon part are greatly different. The diameter was increased, that is, the first cross performance was deteriorated. In addition, when the manufactured balloon is deflated, a highly rigid part forms a wrapping wing, which may reduce the risk of damaging the blood vessel and the recross performance of the stenosis. It was.

  The present invention aims to solve the above-mentioned problems, and its purpose is a balloon for a balloon catheter that can be suitably used for percutaneous angioplasty such as PTCA and PTA. It is possible to manufacture from the same material throughout, and it is possible to stabilize the quality by the uniform film thickness and shape of the balloon, especially the balloon straight tube, and it has excellent wrapping performance and cloth performance. The object is to provide a balloon for a balloon catheter.

As a result of intensive studies on the above problems, the present inventors have invented a balloon for a balloon catheter to be expanded in a blood vessel described below.
That is, the present invention is a balloon for a balloon catheter used for a balloon catheter, wherein the balloon is formed of a resin composition and has a softening temperature lower than that of an adjacent portion in a vertical cross section perpendicular to the axial direction. The present invention relates to a balloon for a balloon catheter having at least one part.

  The present invention also relates to the balloon for a balloon catheter, wherein the balloon is formed of the same resin composition.

The present invention also relates to the balloon for balloon catheter, wherein the balloon has a straight tube portion, and the thickness of the straight tube portion is substantially uniform.
The present invention also relates to the balloon for a balloon catheter, wherein the softening temperature of the low temperature portion is lower by 5 ° C. or more than adjacent sites.

  The present invention also relates to the balloon for a balloon catheter, wherein the balloon has two or more low-temperature parts.

  The present invention also relates to the balloon for a balloon catheter, wherein an acute center angle is 60 ° or more in at least one arc formed by the low temperature portion and the closest low temperature portion.

  The present invention also relates to the balloon for a balloon catheter according to any one of claims 1 to 6, wherein the balloon is folded with the low temperature portion serving as a wing portion.

According to the present invention, the balloon of the balloon catheter can be made of the same material, does not require complicated or expensive equipment, has a small wrapping dimension after balloon expansion, and reproducibility of the wrapping shape (shape stability). To produce a practical and useful balloon. In addition, the balloon manufactured in the present invention has a uniform thickness in the circumferential direction and the axial direction in the vertical cross section perpendicular to the axial direction of the straight tube portion of the balloon, and has excellent mechanical strength. In this case, the wrapping shape is stable and the size is small, so that the cross performance with respect to the narrowed portion is not deteriorated.

It is a schematic perspective view of an over-the-wire type (OTW type) among general balloon catheters. It is a schematic perspective view of a high-speed exchange type (RX type) among general balloon catheters. FIG. 6 is a view showing a longitudinal section of an RX balloon catheter that is a general RX balloon catheter and that has a coaxial guide wire lumen portion. FIG. 4 is a cross-sectional view of a portion corresponding to A-A ′ in FIG. 3. FIG. 3 is a cross-sectional view of an extrusion die used for providing a balloon tube having a protrusion of the present invention (a vertical cross-sectional view with respect to the resin flow direction, (a) for an outer protrusion, and (b) for an inner protrusion. . In the balloon tube which has a projection part used for this invention, (a) Side view, (b) The cross section of the balloon tube with a narrow projection part width | variety, (c) The cross section of the balloon tube with a wide projection part width | variety. It is the (a) side view and (b) sectional view in the balloon manufactured from the balloon tube which has four projection parts. It is balloon sectional drawing at the time of wrapping the balloon of FIG. It is the tube for balloons which two adjacent protrusion parts exist in the space | interval of 120 degrees (acute angle), (a) Side view and (b) Sectional drawing. FIG. 10 is a (a) side view and (b) cross-sectional view of a balloon manufactured with the balloon tube of FIG. 9. It is sectional drawing of the balloon at the time of wrapping the balloon of FIG. It is a vertical sectional view of a two-layer balloon tube composed of the same resin material in the circumferential direction.

  Hereinafter, various embodiments of a balloon catheter and a balloon according to the present invention will be described in detail with reference to the drawings. However, the present invention is not limited thereto.

  The balloon catheter is mainly composed of a balloon and a shaft, and the balloon is joined to the distal portion of the shaft. In the general balloon catheter, the shaft is composed of a proximal shaft and a distal shaft, and the proximal portion of the distal shaft is joined to the distal side of the proximal shaft. An adapter member for holding the balloon catheter is joined to the proximal end of the proximal shaft. A portion of the distal shaft is formed from an inner shaft and an outer shaft that coaxially surrounds the inner shaft, the inner shaft extending distally beyond the outer shaft. A coaxial type in which a guide wire lumen is formed in the lumen of the inner shaft is generally used, but the structure beyond that is not particularly limited. That is, the OTW type shown in FIG. 1 or the RX type shown in FIG. 2 may be used. Further, other structures may be used.

In the case of a typical RX type balloon catheter which is a coaxial type in which the guide wire lumen portion 1 is formed in the inner shaft lumen 2 as shown in FIG. 3, the coaxial type portion (corresponding to AA ′ in FIG. 3). The cross section of the portion to be constructed is as shown in FIG.
In general, a balloon has a straight tube portion 5A and joints 5D and 5E on the distal and proximal sides thereof, and tapered portions 5B and 5C between the straight tube portion 5A and the joints 5D and 5E.

  Although the dimensions of the balloon are determined by the intended use of the balloon catheter, the balloon suitable for carrying out the present invention has an outer diameter of the straight pipe portion when expanded of 1.00 mm to 35.00 mm. The length of is from 5.00 mm to 300.00 mm.

  The balloon according to the present invention has at least one low temperature portion over the entire length of the balloon in the balloon cross section of the balloon straight tube portion at the circumferential portion where the softening temperature of the resin composition is lower than the portions adjacent to both sides. Therefore, it is excellent in wrapping property and rewrapping property. The softening temperature in the present invention means that when the sample temperature is gradually raised while pressing the tip of the compression probe provided with a thin needle-like protrusion against the sample with a constant load, the tip of the compression probe is applied to the sample. Indicates the threshold temperature at which subduction begins.

  When a balloon having a part with a different softening temperature is warmed to room temperature or higher in warm water or body blood, a part with a low softening temperature can have higher flexibility than a part with a high softening temperature. In general, at the time of wrapping, the wing part is subjected to larger deformation than the groove part. For example, when the balloon is wrapped from the expanded state to four wings, the groove portion is formed by bending about 90 ° in the balloon cross section, but the wing portion is formed by bending about 180 °. , When wrapping, tends to become wings. For this reason, in this invention, there exists a tendency for the softening part 20 with a low softening temperature to form a wing | blade part at the time of lapping.

The balloon or balloon tube according to the present invention is not particularly limited as long as it is formed of a material mainly composed of a resin composition, but is preferably formed of the same resin composition throughout. The same resin composition may be a single resin material or a blend resin material formed of several different resin materials. Further, it may have a multilayer structure formed of two or more layers in the radial direction of the balloon or balloon tube.
In the case of a multilayer structure in the radial direction, each layer is made of the same resin material in the circumferential direction.

  The method for producing a balloon according to the present invention is characterized in that different characteristics can be imparted even with the same material, which was not easy in the prior art, and finally, when producing a balloon, a melt extrusion process, a balloon blow molding process It is preferable that the resin is formed of a single resin material in that the production yield is improved.

  The resin material is not particularly limited as long as it is a material suitable for a balloon for a balloon catheter, but is preferably selected from polyolefin, polyurethane, polyether, polyester, and polyamide. In particular, in the case of the balloon catheter for dilatation according to the present invention, a resin composition mainly composed of polyamide is preferable from the viewpoint of excellent pressure strength and flexibility necessary for dilating the constricted portion.

  Although one form of the manufacturing method of the balloon of this invention is demonstrated in detail below, the manufacturing method of the balloon of this invention is not limited to this.

The method for manufacturing a balloon according to the present invention includes a protrusion having a tip region protruding in the radial direction of the outer peripheral surface or the inner peripheral surface in a cross section perpendicular to the axial direction of the balloon tube (hereinafter referred to as a tube cross section). The balloon tube is formed by using a balloon tube 16 formed by biaxial stretching by blow molding or vacuum molding.
Thereby, the film thickness is substantially uniform in the circumferential direction, that is, the part derived from the protrusion 16 and the part derived from the non-projection part 22 are equivalent in thickness, but the part derived from the protrusion 16 has the wing part at the time of wrapping. A balloon that can be formed and folded and stably reduced in diameter can be manufactured.
Moreover, it is preferable to have the protrusion part 16 over the full length of an axial direction.

  As shown in FIG. 6b, the protrusion 16 has a distal end region 18 projecting outward from the outer peripheral surface 17 of the tube cross section to the balloon tube outer side, and a proximal end region 19 defined by the outer peripheral surface 17 and the inner peripheral surface 15. Become. The tip region 18 refers to a region protruding from a perfect circle in the tube cross section. In addition, the base end region 19 indicates a region surrounded when connecting both hems of the distal end region 18 and the center of the balloon tube in a perfect circle.

The tip region may be provided so as to protrude from the inner peripheral surface 15 to the inside of the balloon tube, or may be provided so as to protrude from both the outer peripheral surface and the inner peripheral surface.
The balloon tube having the protrusion 16 that can be used in the present invention preferably has different softening temperatures between the protrusion 16 and the non-protrusion 22. If the protrusion 16 and the non-protrusion 22 have different softening temperatures, the wrapping property of the manufactured balloon can be further improved.

  In addition, the softening temperature in the balloon manufacturing method according to the present invention, as described above, gradually increased the sample temperature while pressing the tip of the compression probe provided with the thin needle-like protrusion against the sample with a constant load. In this case, the temperature indicates a threshold temperature at which the tip of the compression probe starts to sink into the sample.

  The method for producing the balloon tube having the protruding portion 16 projecting in the radial direction used in the method for producing a balloon of the present invention is not particularly limited, but extrusion molding is preferable in that a portion having a different softening temperature can be easily provided. . In the present invention, when a balloon tube that can be suitably used is manufactured by an extrusion molding method, an extrusion mold in which a narrow channel 11 is perforated so as to correspond to a desired projection shape and projection position is used. By pouring the molten resin, it is possible to manufacture a balloon tube having a protrusion 16 protruding in the radial direction. When providing the protrusion 16 projecting to the outside of the balloon tube, as shown in FIG. 5a, the outer mold 13 can be provided with a narrow channel 11 that is bored radially outward. Further, when providing the protrusion 16 projecting inside the balloon tube, as shown in FIG. 5b, the inner mold 23 can be provided with a narrow channel 11 that is bored radially inward. When the molten resin flows through the narrow channel 11, the tip region 18 of the protrusion 16 is formed.

  In extrusion molding, the molten resin receives heat from the mold and flows through the mold while being heated. On the contrary, it is known that the mold is cooled by taking heat from the resin. However, since the narrow portion channel 11 formed in the mold has a small amount of resin flowing in, the mold part forming the narrow portion channel 11 hardly takes heat away from the resin, and the temperature of the narrow portion channel 11 is narrow. It is kept at a higher temperature than the mold part other than the partial flow path 11. Further, since the narrow channel 11 is narrow, the flowing resin is subjected to high shear stress, and heat generation is promoted. Therefore, the resin flowing through the narrow channel 11 is extruded at a higher temperature than the resin flowing through the wide channel 12. Further, the resin in the vicinity of the narrow channel 11 is also affected by the high temperature resin flowing in the narrow channel 11 and is extruded at a higher temperature than the resin in the vicinity of the narrow channel 11.

  In extrusion molding, when the temperature of the molten resin increases, the degree of molecular orientation of the obtained molded product tends to decrease. For this reason, the resin flowing in the narrow channel 11 and the vicinity thereof is extruded at a higher temperature than the resin flowing in the wide channel 12 or the narrow channel 11 and the corresponding part of the obtained molded product. Tends to be low-oriented compared to other parts such as peripheral parts.

  In general, when the primary structure of a molecular substance is the same, the lower the degree of molecular orientation, the lower the characteristic temperature including the melting point, glass transition point, and softening point. Therefore, a balloon tube formed by extrusion using a mold provided with a narrow channel has a protrusion even when the protrusion and the non-protrusion are made of the same resin composition. The softening temperature of 16 tends to be lower than the softening temperature of the non-projecting portion 22.

Next, in the balloon manufacturing method of the present invention, a balloon is formed using a balloon tube. The molding method is not particularly limited, but blow molding or vacuum molding is preferable.
A balloon tube that can be suitably used in the present invention is placed in a mold, and a balloon having the same shape as the balloon mold can be formed by stretching in the axial direction and the radial direction by a biaxial stretching process. .

The shape of the balloon mold that can be used in the present invention is not particularly limited, but a general round mold is more preferable in that a balloon having a uniform film thickness and shape can be produced.
Moreover, in the process of manufacturing a balloon from a balloon tube, the biaxial stretching process may be performed under heating conditions or may be performed a plurality of times. The axial stretching may be performed simultaneously with the radial stretching, or may be performed before or after the radial stretching. Furthermore, an annealing treatment may be performed after stretching in order to stabilize the shape and dimensions of the balloon. The balloon molded by the above method can have the characteristics of the balloon tube before molding. That is, the portion of the balloon corresponding to the projection 16 of the balloon tube can be molded with a softening temperature lower than that of the portion corresponding to the non-projection 22.
In the present invention, a portion of the balloon corresponding to the protrusion 16 at the time of the balloon tube is referred to as a softening portion 20, and a portion corresponding to the non-protrusion 22 is referred to as a non-softening portion 21.

  Further, in the blow molding and vacuum forming, the balloon tube is pressed against the balloon mold with a high stress. Therefore, in the process of forming the balloon tube as a balloon, the protrusion 16 in the balloon tube loses its shape, The film thickness of the softened portion 20 and the non-softened portion 21 in the straight tube portion of the obtained balloon tends to be substantially uniform. In order to make the film thickness of the softened portion 20 and the non-softened portion 21 substantially uniform, it is desirable that the protruding portion 16 of the balloon tube protrudes radially outward in the tube cross section. The protrusions 16 that protrude radially outwardly are pressed evenly against the mold during balloon molding, and are uniformly leveled. Therefore, the protrusion 16 has a more uniform film thickness than the case of protruding radially inward. There is a tendency to produce balloons.

  In the method for manufacturing a balloon according to the present invention, a balloon having a portion having different thermosoftening characteristics can be manufactured by using a balloon tube having the protrusions 16 or having portions having different heat softening characteristics. .

  In the balloon manufactured by the method for manufacturing a balloon according to the present invention, the softened portion 20 having a low softening temperature can form a wing portion during wrapping. In the present invention, the film thickness of the balloon can be made substantially uniform in the circumferential direction.

  The balloon manufactured by the method for manufacturing a balloon according to the present invention does not control the wrapping by providing a difference in the thickness of the balloon, but controls the wrapping by providing a portion having different thermal softening characteristics. There is a feature, and since the wing portion that contacts the blood vessel wall at the time of insertion into the body is formed by the softened portion of the balloon, the risk of damaging the blood vessel and the recross performance with respect to the narrowed portion are excellent.

  In the balloon manufactured by the method for manufacturing a balloon of the present invention, it is desirable that the softening temperature of the softened portion 20 is 5 ° C. or more lower than the softening temperature of the non-softened portion 21 in order to stably control the wrapping. If there is a difference of 5 ° C. or more, the same effect can be obtained in any case. Such a balloon can be manufactured by using a balloon tube in which the softening temperature of the protrusion 16 is lower by 5 ° C. or more than the softening temperature of the non-protrusion.

  Further, in order to stably wrap at the intended portion of the balloon, it is preferable that the projection 16 of the balloon tube is formed high and thin. For example, as the shape of the protrusion 16 in the tube cross section, a shape having a high aspect ratio value represented by a ratio of a radial length of the distal end region 18 and an arc length that is an interface between the distal end region 18 and the proximal end region 19 is preferable. For example, a shape such as an acute triangle (FIG. 6B) is more preferable than a semicircular shape (FIG. 6C).

  The longer the radial length of the protrusion 16 in the balloon tube (hereinafter, the higher the height), that is, the higher the height of the tip region 18, the more easily the effect of the present invention can be obtained. The high protrusion 16 can be formed when the height of the narrow channel 11 of the mold during extrusion molding is high. When the height of the narrow channel 11 is high, the number of mold parts maintained at a high temperature during extrusion molding increases, and shear heat generation due to the molten resin flowing through the narrow channel 11 is likely to occur. Therefore, since the temperature difference during processing of the resin flowing through the narrow channel 11 and the resin flowing through the wide channel 12 increases, the difference in the orientation of the resin also tends to increase. Therefore, the difference between the softening temperature of the protrusion 16 and the softening temperature of the non-protrusion 22 is increased, and the difference between the softening temperatures of the softened portion 20 and the non-softening portion 21 in the balloon is increased, thereby obtaining a stable wrapping effect. It becomes easy to be done.

  The height of the tip region 18 of the projection of the balloon tube that can be suitably used in the present invention is 15% or more of the height of the proximal region 19 in that a stable wrapping effect of the balloon is easily obtained. It is preferable that Molded from balloon tubing. The height of the base region 19 indicates the thickness of the perfect circle portion of the balloon tube, and the height of the protrusion 16 is preferably 115% or more of the balloon tube thickness.

  In addition, the width of the protrusion 16 is an arc that the proximal end region 19 of the protrusion 16 occupies with respect to the circumference of the tube in the tube cross section of the balloon tube because it is easy to obtain a stable wrapping effect of the balloon. It is preferable to form such that the total of the total amount becomes 50% or less.

  If the width of the protrusion 16 is narrow, the temperature difference during processing of the protrusion 16 and the non-protrusion 22 tends to increase in the process of forming the protrusion. As a result, the softened portion 20 and the non-softened portion 21 of the balloon This is because the difference in softening temperature tends to increase.

  Moreover, it is preferable that an acute center angle is 60 ° or more in an arc formed by the two closest protrusions. When the softened portions formed from the protrusions 16 are too close to each other, that is, when the central angle on the acute angle side formed by the protrusions is less than 60 °, the closest softening portions are at the time of balloon wrapping. They tend to compete and tend to be difficult to wrap at the intended site.

  In the present invention, the number of the protrusions 16 of the balloon tube is not particularly limited as long as the wrapping property can be obtained, but by providing two protrusions 16, the effect of the present invention for solving the problem can be obtained. Can be obtained. For example, the balloon (FIG. 10) created from the balloon tube (FIG. 9) in which the protrusions 16 are arranged at two locations so that the central angle on the acute angle side formed by the protrusions is 120 ° is two locations at the time of wrapping. Therefore, the non-softened portion at a position of 120 ° from the two softened portions 20 also forms a wing portion, and the balloon is wrapped into three wings.

  Further, if the protrusions 16 are provided at three or more locations, it is possible to wrap to three or more blades starting from the softened portion 20 derived from the protrusions 16. Therefore, by providing two or more protrusions 16, it is possible to wrap the balloon into three or more wings, and the effect of the present invention for solving the problem can be obtained.

  Specific examples and comparative examples according to the present invention are described in detail below, but the present invention is not limited to the following examples.

Example 1
A balloon tube was prepared by melt extrusion molding using a 72D polyamide elastomer having a durometer hardness (trade name: PEBAX7233SA01: manufactured by Arkema). As the melt extrusion molding die for the balloon tube, the one having a cross-sectional shape having a narrow channel portion 11 serving as a balloon projection on the tube outer layer side shown in FIG. 5 (a) is used. A balloon tube having the shape shown in FIG. The dimensions of the balloon tube were an outer diameter of the non-projection part: 1.00 mm and an inner diameter: 0.50 mm. Four protrusions existed at equal intervals in a cross section perpendicular to the longitudinal direction, and were prepared to have a width of 33 μm and a height of 40 μm.

  Next, this balloon tube was subjected to biaxial stretch blow molding using a blow molding die to produce a balloon having an outer diameter of the straight tube portion of 3.00 mm and a length of the straight tube portion of 15 mm.

  The produced balloons are as shown in Table 2. The film thickness of the straight tube part was measured with a micrometer, and the softened part was 17.2 μm and the non-softened part was 16.5 μm. The balloon tube and the softening point of the balloon were measured at the center of each of the protrusions and non-protrusions using a nanothermal analysis VESTA system (extremely small area thermal analyzer) manufactured by Anasys Instruments. As a result, in the balloon tube, the protruding portion was 130 ° C. and the non-projecting portion 143 ° C., and in the balloon, the softened portion was 136 ° C. and the non-softened portion was 146 ° C.

  Next, a tube (outer diameter: 0.56 mm, inner diameter: 0.42 mm) is extruded by using high density polyethylene (HY540, Nippon Polychem Co., Ltd.) as the inner shaft tube of the balloon catheter, and polyamide is used as the outer shaft tube. A tube having an outer diameter of 0.88 mm and an inner diameter of 0.71 mm was prepared by extrusion molding using an elastomer (trade name: PEBAX7233A01: manufactured by Arkema). Using these and an adapter member obtained by injection molding using polycarbonate (Makloron 2658, Bayer), an OTW balloon catheter having a coaxial structure was produced.

(Example 2)
The balloon tube, balloon, and catheter were manufactured using the same materials, methods, and molds as in Example 1 except that the projection of the balloon tube had a width of 33 μm and a height of 35 μm.
The thickness of the straight tube portion of the produced balloon was 17.0 μm for the softened portion and 16.5 μm for the non-softened portion. Regarding the softening point, the balloon tube had a protrusion 140 ° C. and a non-protrusion 145 ° C., and the balloon had a softening portion 150 ° C. and a non-softening portion 153 ° C.

(Example 3)
Tube forming was performed so that two protrusions of the balloon tube were arranged at a 120 ° positional relationship, and balloon tubes, balloons, and catheters were manufactured using the same materials, methods, and molds as in Example 1. The film thickness of the straight tube portion of the balloon was 17.0 μm for the softened portion and 16.0 μm for the non-softened portion. Regarding the softening point, the balloon tube had a protrusion 131 ° C. and a non-protrusion 143 ° C., and the balloon had a softening part 135 ° C. and a non-softening part 146 ° C.

Example 4
Balloon tubes, balloons, and catheters were prepared using the same materials, methods, and molds as in Example 1 except that five projections of the balloon tube were equally spaced, width of 33 μm, and height of 50 m. The film thickness of the straight tube portion of the balloon was 17.8 μm for the softened portion and 16.0 μm for the non-softened portion. With respect to the softening point, the balloon tube had a projection of 138 ° C. and a non-projection of 144 ° C., and the balloon had a softening portion of 142 ° C. and a non-softening portion of 155 ° C.

(Example 5)
In the production of a balloon tube, a nylon tube having a durometer hardness of 74D (trade name: RILSAN AESN OTL: manufactured by Arkema Inc.) is used as the material, and the other materials, methods, and molds are the same as those in Example 1. Balloons and catheters were prepared. The dimensions of the balloon tube were an outer diameter of the non-projection part: 1.00 mm and an inner diameter: 0.50 mm. Three protrusions were present at equal intervals in a cross section perpendicular to the longitudinal direction, and the protrusions were made to have a width of 35 μm and a height of 50 μm. The film thickness of the straight tube portion of the balloon was 17.0 μm for the softened portion and 16.0 μm for the non-softened portion. Regarding the softening point, the balloon tube had a projection of 144 ° C. and a non-projection of 164 ° C., and the balloon had a softening portion of 158 ° C. and a non-projection of 168 ° C.

(Example 6)
The balloon tube, balloon, and catheter were manufactured using the same materials, methods, and molds as in Example 5 except that the projection of the balloon tube had a width of 35 μm and a height of 30 μm. The film thickness of the straight tube portion of the balloon was 16.7 μm for the softened portion and 16.2 μm for the non-softened portion. With respect to the softening point, the balloon tube had a protrusion 158 ° C. and a non-protrusion 162 ° C., and the balloon had a softening portion 162 ° C. and a non-softening portion 164 ° C.

(Comparative Example 1)
A balloon tube was prepared by melt extrusion molding using a 72D polyamide elastomer having a durometer hardness (trade name: PEBAX7233SA01: manufactured by Arkema). The balloon tube melt extrusion molding die having a perfect circular section was used to produce a balloon tube having a perfect circular section. The balloon tube has an outer diameter of 1.00 mm and an inner diameter of 0.50 mm. The balloon was produced by the same method as in Example 1, and the film thickness and the softening point were measured. The film thickness of the straight tube portion of the balloon was 15.3 μm. The softening point was 144 ° C. for the balloon tube and 154 ° C. for the balloon.
Next, after producing a catheter with the same material and method as in Example 1, a general folding device for a balloon catheter is used to wrap the balloon into four wings, thereby physically bracing the wrapping shape. It was.

(Comparative Example 2)
A balloon tube was prepared by melt extrusion using 74D nylon 12 (trade name: RILSAN AESN OTL: manufactured by Arkema Co., Ltd.) with durometer hardness. After producing the tube, balloon, and catheter, the wrapping-shaped brazing was performed. The film thickness of the straight tube portion of the balloon was 17.7 μm. The softening point was 162 ° C. for the balloon tube and 164 ° C. for the balloon.

(Evaluation of balloon wrapping performance)
For each of the five balloon catheters of Examples 1 to 7 and Comparative Examples 1 and 2, the inner part of the balloon was placed under a negative pressure, wound around the inner shaft, covered with a balloon protection tube, and EOG sterilized. The balloon wrapping performance was evaluated. An outline of the evaluation method is shown below.

  The guiding catheter was placed in a water bath filled with 37 ° C. physiological saline. The balloon catheter was placed with the guide wire so as to be exposed 100 mm from the distal end of the guiding catheter. Then, the mixed solution of contrast medium and physiological saline was introduced into the balloon catheter up to 14 atm with an indeflator and held for 30 seconds, and then the balloon was immediately deflated. For each level, five samples were used, and each sample was repeatedly evaluated five times. The balloon wrapping shape was confirmed in every sample for every measurement. These evaluation results are shown in Table 1.

(Evaluation results)
In Examples 1 to 6, the softened part derived from the protrusion part formed a wing part, and each could be controlled to a desired wrapping shape.
Although Comparative Examples 1 and 2 were brazed as four blades, none of the wrapping shapes could be controlled.

1. 1. Guide wire lumen Inflation lumen 5. 10. Balloon for balloon catheter Narrow channel 12. Wide channel 15. Inner peripheral surface 16. Projection 17. Outer peripheral surface 18. Tip region 19. Proximal region 20. Softening part 21. Non-softening part 22. Non-projection 24. First resin material layer 25. Second resin material layer

Claims (5)

A balloon for a balloon catheter used for a balloon catheter, wherein the balloon is formed of a resin composition and has at least one low temperature portion having a softening temperature lower than that of an adjacent portion in a vertical cross section perpendicular to the axial direction. and it is,
The low temperature part and the adjacent part are formed of the same resin composition,
The balloon has a straight tube portion, and the balloon tube balloon has a substantially uniform film thickness . The balloon for balloon catheter according to claim 1 , wherein the softening temperature of the low temperature part is lower by 5 ° C or more than adjacent sites. The balloon, balloon balloon catheter of claim 1 or 2 has the low-temperature portion 2 or more places. Wherein the low temperature portion, at least one arc forming the low temperature portion closest, balloon balloon catheter of claim 3 acute central angle is 60 ° or more. The balloon for balloon catheter according to any one of claims 1 to 4 , wherein the balloon is folded with the low-temperature portion serving as a wing portion.