Method for manufacturing balloon catheters

Abstract

To provide a manufacturing method of a balloon catheter provided with a protrusion on a surface of a part of the balloon that expands to a relatively large extent when the balloon is inflated.SOLUTION: A manufacturing method of a balloon catheter includes: a process (A) for preparing a resin tubular body 21 having a protrusion 23 on the surface; a process for preparing a first metal mold having a balloon-shaped lumen and in which a concave part is formed on the inner wall surface; a first molding process (B) for expanding the resin tubular body 21 in the first metal mold and causing the protrusion 23 of the resin tubular body 21 to enter the concave part on the inner wall surface of the first metal mold to acquire an intermediate mold 41 having the protrusion 23 on the surface; a process (C) for removing part of the protrusion 23 of the intermediate mold 41; a process for preparing a second metal mold having a balloon-shaped lumen and formed with a concave part on the internal wall surface; and a second molding process (D) for expanding the intermediate mold 41 in the second metal mold and causing the protrusion 23 of the intermediate mold 41 to enter the concave part on the inner wall surface of the second metal mold.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a balloon catheter, and more particularly to a method for manufacturing a balloon catheter provided with a balloon having protrusions on its surface.

Background Art

[0002] It is known that stenosis occurs in blood vessels, which are channels for blood circulation in the body, and various diseases are caused by stagnation of blood circulation. In particular, when stenosis occurs in the coronary arteries that supply blood to the heart, there is a risk of serious diseases such as angina pectoris and myocardial infarction. As one method for treating such vascular stenosis, there is angioplasty (PTA, PTCA, etc.) in which a balloon catheter is used to expand the stenosis. There is known a balloon catheter having protrusions provided on the surface of the balloon. By using such a balloon catheter, when the balloon is expanded, the protrusions of the balloon can be made to bite into the stenosis to create cracks in the stenosis, thereby effectively expanding the stenosis. As a method for manufacturing a balloon catheter having protrusions provided on the surface of the balloon, for example, Patent Document 1 discloses a manufacturing method including a step of inserting a resin parison into the inner cavity of a mold having grooves formed on its inner wall surface, a step of expanding the parison in the mold to allow the resin to enter the grooves of the mold, and a step of removing the parison from the mold before the resin of the parison reaches the bottom of the grooves.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a balloon catheter with protrusions on the surface of the balloon, it is preferable that the protrusions are provided on the portion of the balloon that expands significantly when the balloon is inflated, and not on the portion that does not expand significantly. This allows for effective expansion of the stenotic portion when the balloon is inflated, and when the balloon is deflated, it becomes easier to neatly fold the balloon, thereby improving the passability of the balloon into body cavities and endoscopic forceps channels. The present invention provides a method for manufacturing such a balloon catheter, and moreover, a method for manufacturing a balloon catheter in which protrusions are provided on the surface of the balloon, specifically on the portion of the balloon that expands relatively significantly when the balloon is inflated. [Means for solving the problem]

[0005] The present invention includes the following method for manufacturing a balloon catheter. [1] A step of preparing a resin tubular body having a longitudinal direction and a radial direction and having protrusions on its surface, Steps to prepare a first mold having a lumen extending in a first axial direction from the proximal to the distal side, wherein the inner wall surface forming the lumen comprises a first straight pipe forming portion, a first proximal tapered forming portion located proximal to the first straight pipe forming portion and whose inner diameter decreases as it moves away from the first straight pipe forming portion, a first proximal sleeve forming portion located proximal to the first proximal tapered forming portion, a first distal tapered forming portion located distal to the first straight pipe forming portion and whose inner diameter decreases as it moves away from the first straight pipe forming portion, and a first distal sleeve forming portion located distal to the first distal tapered forming portion, wherein recesses are formed on the inner wall surfaces of the first straight pipe forming portion, the first proximal tapered forming portion, the first distal tapered forming portion, the first proximal sleeve forming portion, and the first distal sleeve forming portion; A first molding step to obtain an intermediate molded body having the projection on its surface, wherein the resin tubular body is placed in the lumen of the first mold, the resin tubular body is expanded to contact the inner wall surface of the first mold, and the projection is inserted into the recess, thereby obtaining an intermediate molded body having a straight tube portion that contacts the first straight tube forming portion, a proximal tapered portion that contacts the first proximal tapered portion, a proximal sleeve portion that contacts the first proximal sleeve forming portion, a distal tapered portion that contacts the first distal tapered portion, and a distal sleeve portion that contacts the first distal sleeve forming portion, A protrusion removal step is performed to remove the protrusions present on the proximal sleeve portion and the distal sleeve portion of the intermediate molded body. Steps to prepare a second mold having a lumen extending in a second axial direction from the proximal to the distal side, wherein the inner wall surface forming the lumen comprises a second straight tube forming portion, a second proximal taper forming portion located proximal to the second straight tube forming portion and whose inner diameter decreases as it moves away from the second straight tube forming portion, a second proximal sleeve forming portion located proximal to the second proximal taper forming portion, a second distal taper forming portion located distal to the second straight tube forming portion and whose inner diameter decreases as it moves away from the second straight tube forming portion, and a second distal sleeve forming portion located distal to the second distal taper forming portion, wherein the length of the second straight tube forming portion in the second axial direction is formed to be longer than the length of the first straight tube forming portion in the first axial direction, the inner diameter of the second straight tube forming portion is formed to be larger than the inner diameter of the first straight tube forming portion, and a recess is formed on the inner wall surface of the second straight tube forming portion. A second molding step involves placing the intermediate molded body, from which a portion of the protrusions obtained in the protrusion removal step has been removed, into the cavity of the second mold, expanding the intermediate molded body to bring it into contact with the inner wall surface of the second mold, and causing the protrusions to enter the recesses. A method for manufacturing a balloon catheter having [a certain feature]. [2] The method for manufacturing a balloon catheter according to [1], wherein in the first molding step, the resin tubular body is expanded while being pulled in the longitudinal direction. [3] A method for manufacturing a balloon catheter according to [1] or [2], wherein in the second molding step, the resin tubular body is expanded without stretching the intermediate molded body in the longitudinal direction. [4] A method for manufacturing a balloon catheter according to any one of [1] to [3], wherein the length from the proximal end of the proximal tapered portion of the intermediate molded body to the distal end of the distal tapered portion is shorter than the length from the midpoint between the proximal and distal ends of the second proximal tapered portion of the second mold to the midpoint between the proximal and distal ends of the second distal tapered portion. [5] A method for manufacturing a balloon catheter according to any one of [1] to [3], wherein the length from the proximal end of the proximal tapered portion of the intermediate molded body to the distal end of the distal tapered portion is shorter than the length in the second axial direction of the second straight tube forming portion of the second mold. [6] The resin tubular body has an enlarged diameter portion in a part of its longitudinal direction, and in the first molding step, the portion of the resin tubular body including the enlarged diameter portion is placed in the lumen of the first mold, according to any one of [1] to [5]. [7] A method for manufacturing a balloon catheter according to any one of [1] to [6], comprising the steps of: preparing a straight tubular resin body having a first section, a second section, and a third section from one side in the longitudinal direction and having protrusions on its surface; and heating the straight tubular resin body to stretch the first section and the third section in the longitudinal direction to obtain a resin tubular body having an enlarged diameter portion in the second section. [Effects of the Invention]

[0006] According to the present invention, a balloon catheter can be easily manufactured in which a projection is provided on the surface of the straight tube portion of the balloon, which is the part that expands significantly when the balloon is inflated. [Brief explanation of the drawing]

[0007] [Figure 1] This diagram shows an example of the configuration of a balloon catheter according to an embodiment of the present invention, and represents a side view of the balloon catheter. [Figure 2] This figure shows a perspective view of the balloon attached to the balloon catheter shown in Figure 1. [Figure 3] It represents a III-III cross-sectional view of the balloon catheter shown in FIG. 1. [Figure 4] It represents a IV-IV cross-sectional view of the balloon catheter shown in FIG. 1. [Figure 5] It represents a schematic diagram of the overall process of the manufacturing method of the balloon catheter according to an embodiment of the present invention. [Figure 6] It represents a perspective view of the resin tubular body to be used in the resin tubular body preparation step of the manufacturing method shown in FIG. 5. [Figure 7] It represents a VII-VII cross-sectional view of the resin tubular body shown in FIGS. 6 and 9. [Figure 8] It represents a schematic diagram of the straight tubular resin tubular body preparation step and the stretching step. [Figure 9] It represents a perspective view of the resin tubular body to be used in the straight tubular resin tubular body preparation step. [Figure 10] It represents an example of the first mold used in the first mold preparation step and represents an axial cross-sectional view of the first mold. [Figure 11] It represents an example of an XI-XI cross-sectional view of the first mold shown in FIG. 10 (including a partially enlarged view around the concave portion of the mold). [Figure 12] It represents another example of an XI-XI cross-sectional view of the first mold shown in FIG. 10 (including a partially enlarged view around the concave portion of the mold). [Figure 13] It represents a schematic diagram of the first molding step. [Figure 14] It represents an example of an XIV-XIV cross-sectional view of the mold and the resin tubular body shown in FIG. 13. [Figure 15] It represents an example of an XV-XV cross-sectional view of the mold and the resin tubular body shown in FIG. 13 (including a partially enlarged view around the concave portion of the mold and the protrusion of the intermediate molded body). [Figure 16] It represents a schematic diagram of the protrusion removal step. [Figure 17] It represents an XVII-XVII cross-sectional view of the intermediate molded body shown in FIG. 16. [Figure 18] It represents an example of the second mold used in the second mold preparation step and represents an axial cross-sectional view of the second mold. [Figure 19]It represents an example of a cross-sectional view taken along line XIX-XIX of the second mold shown in FIG. 18 (including a partially enlarged view around the concave portion of the mold). [Figure 20] It represents a schematic view of the second molding step. [Figure 21] It represents an example of a cross-sectional view taken along line XXI-XXI of the mold and the resin tubular body shown in FIG. 20 (including a partially enlarged view around the concave portion of the mold and the protrusion of the balloon molding).

Mode for Carrying Out the Invention

[0008] Hereinafter, the present invention will be specifically described based on the following embodiments. However, the present invention is not limited by the following embodiments, and it is of course possible to appropriately modify and implement it within a range that conforms to the gist of the foregoing and following descriptions, and all of them are included in the technical scope of the present invention. In each drawing, for convenience, hatching, reference numerals of members, etc. may be omitted, but in such cases, reference shall be made to the specification and other drawings. Also, the dimensions of various members in the drawings may differ from the actual dimensions because priority is given to facilitating understanding of the features of the present invention.

[0009] The present invention relates to a method for manufacturing a balloon catheter provided with a balloon having protrusions on its surface. A balloon catheter is a medical device mainly used in angioplasty (PTA, PTCA, etc.) for expanding a stenosis performed in the treatment of a stenotic part of a blood vessel. It is known that when a stenosis occurs in a blood vessel, which is a flow path for blood circulation in the body, and blood circulation is obstructed, various diseases may occur. In particular, when a stenosis occurs in the coronary artery that supplies blood to the heart, there is a risk of serious diseases such as angina pectoris and myocardial infarction. Since angioplasty is a minimally invasive treatment that does not require thoracotomy such as bypass surgery, it is widely performed. The balloon catheter according to the present invention has protrusions provided on the surface of the balloon, whereby a scoring function can be imparted to the balloon. Therefore, when the balloon is expanded at the stenotic part, it is possible to make the protrusions of the balloon bite into the stenotic part and create cracks in the stenotic part, effectively expanding the stenotic part.

[0010] Before describing the manufacturing method of the balloon catheter of the present invention, the structure of the balloon catheter that can be manufactured by the manufacturing method of the present invention will be described first. Note that the balloon catheter manufactured by the manufacturing method of the present invention is not limited to that shown in the drawings.

[0011] Figures 1 to 4 show examples of the configuration of a balloon catheter that can be manufactured by the manufacturing method of the present invention. Figure 1 shows a side view of the balloon catheter, Figure 2 shows a perspective view of the balloon provided in the balloon catheter shown in Figure 1, Figure 3 shows a III-III cross-sectional view of the balloon catheter shown in Figure 1, and Figure 4 shows an IV-IV cross-sectional view of the balloon catheter shown in Figure 1. Figure 1 shows an example of the configuration of a rapid exchange type balloon catheter.

[0012] The balloon catheter 1 has a shaft 2 and a balloon 10 provided on the outside of the shaft 2. The balloon catheter 1 has a proximal end and a distal end, with the balloon 10 provided at the distal end of the shaft 2. The proximal end of the balloon catheter 1 refers to the direction toward the user (operator) relative to the extending direction of the balloon catheter 1, and the distal end refers to the opposite direction from the proximal end, i.e., the direction toward the target of treatment. The direction from the proximal end to the distal end of the balloon catheter 1 is also called the longitudinal direction.

[0013] The balloon catheter 1 is configured to supply fluid to the inside of the balloon through the shaft 2, and the expansion and contraction of the balloon 10 can be controlled using an indefleror (balloon pressure / depressurization device). The fluid may be pressurized fluid pressurized by a pump or the like. Hereinafter, the fluid supplied to the inside of the balloon 10 will be referred to as the "balloon expansion fluid".

[0014] Shaft 2 is composed of, for example, an inner shaft 3 and an outer shaft 4. The inner shaft 3 is positioned within the lumen of the outer shaft 4. The inner shaft 3 can function as a passage for a guidewire that guides the advancement of shaft 2, and when using balloon catheter 1, the guidewire is inserted through the lumen of the inner shaft 3. The space between the inner shaft 3 and the outer shaft 4 can function as a passage for balloon inflation fluid.

[0015] In the rapid exchange type balloon catheter 1, a guidewire port 7 is provided midway from the distal to the proximal end of the shaft 2. The proximal end of the inner shaft 3 is connected to the guidewire port 7, and the distal end of the inner shaft extends to the distal part of the shaft 2, thereby forming a guidewire insertion passage that extends from the guidewire port 7 to the distal part of the shaft 2.

[0016] The outer shaft 4 may have a proximal outer shaft 4A and a distal outer shaft 4B, in which case it is preferable that the inner shaft 3 is positioned in the lumen of the distal outer shaft 4B. The proximal outer shaft 4A and the distal outer shaft 4B may be made of the same material or of different materials. For example, it is preferable that the proximal outer shaft 4A is made of resin or metal and the distal outer shaft 4B is made of resin. The outer shaft 4 may not be divided into a proximal outer shaft 4A and a distal outer shaft 4B, but may be made of a single member, or the proximal outer shaft 4A and the distal outer shaft 4B may be further made up of multiple tube members.

[0017] It is preferable that a hub 5 is provided on the proximal side of the shaft 2. The hub 5 preferably has a fluid injection section 6 that communicates with the flow path of the balloon expansion fluid in the shaft 2. The balloon 10, shaft 2 (inner shaft 3, outer shaft 4), and hub 5 can be joined using conventionally known joining methods such as adhesives or heat welding.

[0018] Although not shown in the drawings, the balloon catheter may be an over-the-wire type balloon catheter in which the inner shaft extends from the distal to the proximal end of the shaft, and a guidewire insertion passage is formed from the distal to the proximal end of the shaft. In this case, it is preferable that the flow path for the balloon inflation fluid and the guidewire insertion passage provided in the shaft extend to the hub, and that the hub is configured to have a fluid injection section communicating with the flow path for the balloon inflation fluid and a treatment section communicating with the guidewire insertion passage. It is preferable that the hub has a bifurcated structure, with the fluid injection section provided on one of the bifurcated ends and the treatment section on the other.

[0019] It is preferable that the outer surface of shaft 2 is coated. In rapid exchange type balloon catheter 1, it is preferable that the outer surface of one or both of the proximal outer shaft 4A and distal outer shaft 4B is coated, and it is more preferable that the outer surfaces of both the proximal outer shaft 4A and distal outer shaft 4B are coated. In over-the-wire type balloon catheter, it is preferable that the outer surface of the outer shaft is appropriately coated.

[0020] The coating can be hydrophilic or hydrophobic, depending on the purpose. The outer surface of the shaft 2 can be coated by immersing the shaft 2 in a hydrophilic or hydrophobic coating agent, applying a hydrophilic or hydrophobic coating agent to the outer surface of the shaft 2, or covering the outer surface of the shaft 2 with a hydrophilic or hydrophobic coating agent. The coating agent may contain chemicals or additives.

[0021] Examples of hydrophilic coating agents include hydrophilic polymers such as polyvinyl alcohol, polyethylene glycol, polyacrylamide, polyvinylpyrrolidone, and methyl vinyl ether maleic anhydride copolymer, as well as hydrophilic coating agents made from any combination of these polymers.

[0022] Examples of hydrophobic coating agents include polytetrafluoroethylene (PTFE), ethylene fluoride propylene (FEP), perfluoroalkoxyalkanes (PFA), silicone oil, hydrophobic urethane resins, carbon coatings, diamond coatings, diamond-like carbon (DLC) coatings, ceramic coatings, and substances with low surface free energy terminated with alkyl groups or perfluoroalkyl groups.

[0023] It is preferable that a tip 8 is provided at the distal end of the balloon catheter 1. The tip 8 may be provided as a separate component from the inner shaft 3 distal to the distal end of the inner shaft 3, or the distal end of the inner shaft 3 may function as the tip 8 by extending the inner shaft 3 distal to the distal end of the balloon 10.

[0024] The shaft 2 may have radiopaque markers 9 positioned in the longitudinal direction of the balloon 10 to allow confirmation of the balloon 10's position under X-ray fluoroscopy. The radiopaque markers 9 can be positioned, for example, on the inner shaft 3 located inside the balloon 10, preferably at positions corresponding to both ends of the straight section of the balloon 10, or at a position corresponding to the center of the straight section of the balloon 10.

[0025] The balloon 10 has a longitudinal direction and a radial direction, and is formed in a cylindrical shape with openings on the proximal and distal sides (see Figure 2). The radial direction of the balloon 10 is the direction perpendicular to the longitudinal direction and means the direction extending radially from the center of the balloon 10. The balloon 10 also has a circumferential direction, which is the direction along the outer circumference of the expanded balloon 10 in a longitudinal cross-section of the balloon 10.

[0026] The balloon 10 has a proximal sleeve portion 11, a proximal tapered portion 12, a straight tube portion 13, a distal tapered portion 14, and a distal sleeve portion 15 in the longitudinal direction. The straight tube portion 13 is formed in a substantially cylindrical shape extending in the longitudinal direction and has the largest radial length (outer diameter) in the balloon 10. The proximal tapered portion 12 is located on the proximal side of the straight tube portion 13 and connects to the proximal end of the straight tube portion 13. The proximal tapered portion 12 is formed such that its outer diameter decreases as it moves away from the straight tube portion 13. The proximal sleeve portion 11 is located on the proximal side of the proximal tapered portion 12 and connects to the proximal end of the proximal sleeve portion 11. The proximal sleeve portion 11 is formed in a substantially cylindrical shape. The distal tapered portion 14 is located on the distal side of the straight tube portion 13 and connects to the distal end of the straight tube portion 13. The distal tapered section 14 is formed such that its outer diameter decreases as it moves away from the straight pipe section 13. The distal sleeve section 15 is located distal to the distal tapered section 14 and is connected to the distal end of the distal sleeve section 15. The distal sleeve section 15 is formed in a substantially cylindrical shape.

[0027] As described above, the balloon 10 is configured such that when the balloon 10 is expanded in a lesion such as a stenosis, the straight tube portion 13 makes sufficient contact with the lesion, making it easier to perform treatment such as dilation of the lesion. Furthermore, because the balloon 10 has a proximal tapered portion 12 and a distal tapered portion 14, when the balloon 10 is deflated, the outer diameters of the proximal and distal ends of the balloon 10 can be reduced, thereby reducing the step difference between the shaft 2 and the balloon 10, making it easier to insert the balloon 10 into a body cavity or into the forceps channel of an endoscope.

[0028] In the distal portion of the shaft 2, it is preferable that the inner shaft 3 extends distally from the distal end of the outer shaft 4, and that the inner shaft 3 extends through the internal space of the balloon 10 from the proximal sleeve portion 11 to the distal sleeve portion 15. Furthermore, it is preferable that the inner shaft 3 is joined to the inner surface of the distal sleeve portion 15 of the balloon 10, and the outer shaft 4 is joined to the inner surface of the proximal sleeve portion 11 of the balloon 10. With the distal portion of the shaft 2 configured in this way, the balloon expansion fluid can be supplied to the internal space of the balloon 10 through the space between the inner shaft 3 and the outer shaft 4.

[0029] The balloon 10 is made of resin, specifically a thermoplastic resin. Examples of resins that make up the balloon 10 include polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymer; polyester resins such as polyethylene terephthalate and polyester elastomer; polyurethane resins such as polyurethane and polyurethane elastomer; polyamide resins such as polyphenylene sulfide resin, polyamide, and polyamide elastomer; fluororesin, silicone resin, and natural rubber such as latex rubber. These may be used individually or in combination of two or more. Among these, polyamide resins, polyester resins, and polyurethane resins are preferably used. In particular, it is preferable to use elastomer resins from the viewpoint of thinning the balloon 10 and its flexibility. For example, among polyamide resins, nylon 12 and nylon 11 are suitable materials for the balloon 10, and nylon 12 is preferably used because it can be molded relatively easily during blow molding. Also, from the viewpoint of thinning the balloon 10 and its flexibility, polyamide elastomers such as polyether ester amide elastomer and polyamide ether elastomer are preferably used. In particular, polyether ester amide elastomers are preferred due to their high yield strength and good dimensional stability of the balloon 10.

[0030] The balloon 10 has a projection 16 on the outer surface of the straight tube 13. The presence of the projection 16 on the outer surface of the straight tube 13 gives the balloon 10 a scoring function. When the balloon 10 is expanded, it can bite into the calcified stenosis, causing a crack in the stenosis. Therefore, it is possible to expand the stenosis while suppressing intima dissection. Furthermore, it is possible to increase the strength of the balloon 10 and suppress over-expansion during pressurization.

[0031] The projection 16 may also be provided on the outer surface of the proximal tapered portion 12 and / or the distal tapered portion 14, but it is preferable that the projection 16 is not provided on the side of the proximal tapered portion 12 and the distal tapered portion 14 that is farther from the straight tube portion 13. For example, in the proximal tapered portion 12, it is preferable that the projection 16 is not provided in the proximal 1 / 2 range of the proximal tapered portion 12, more preferably not in the proximal 2 / 3 range, and even more preferably not in the proximal 3 / 4 range. In the distal tapered portion 14, it is preferable that the projection 16 is not provided in the distal 1 / 2 range of the distal tapered portion 14, more preferably not in the distal 2 / 3 range, and even more preferably not in the distal 3 / 4 range. This makes it easier to neatly fold the balloon 10 when it is deflated, and for example, the balloon 10 can be folded so that the projection 16 is not exposed. Therefore, the ease of inserting the balloon 10 into the body cavity or the forceps channel of an endoscope can be improved. It is preferable that the protruding portion 16 is not provided on the proximal sleeve portion 11 and the distal sleeve portion 15.

[0032] The projections 16 are formed to protrude radially from the outer surface of the balloon 10. The projections 16 can be provided linearly or as dots on the outer surface of the straight tube portion 13, for example. In the former case, the projections 16 are provided as ridges. In the latter case, it is preferable to provide multiple dot-shaped projections 16, and it is more preferable to provide multiple dot-shaped projections 16 arranged in a row. By providing the projections 16 in this way, it becomes easier to control the direction in which cracks form in the constricted portion. The direction of extension of the linear projections 16 or the arrangement direction of the multiple dot-shaped projections 16 may be, for example, the longitudinal direction of the balloon 10, the direction extending spirally in the longitudinal direction, or the circumferential direction. However, from the viewpoint of ease of manufacturing the balloon 10 having the projections 16, it is preferable that the direction of extension of the linear projections 16 or the arrangement direction of the multiple dot-shaped projections 16 is the longitudinal direction of the balloon 10.

[0033] It is preferable that multiple projections 16 are provided at different positions in the circumferential direction on the straight tube portion 13 of the balloon 10. That is, it is preferable that the projections 16 are provided at multiple locations in the circumferential direction of the balloon 10. In this case, it is preferable that the projections 16 are arranged at approximately equal intervals in the circumferential direction of the straight tube portion 13 of the balloon 10. This makes it possible to create cracks at multiple locations in the constricted section when the balloon 10 is expanded. For example, it is preferable that linear projections 16 extending in the longitudinal direction are provided at multiple locations in the circumferential direction of the balloon 10, or that multiple point-shaped projections 16 arranged in the longitudinal direction form a group of projections, and that this group of projections is provided at multiple locations in the circumferential direction of the balloon 10. In the latter case, it is preferable that the circumferential spacing of the group of projections is wider than the longitudinal spacing of the multiple projections 16 included in one group of projections. It is preferable that the projections 16 are provided at two or more positions in the circumferential direction of the balloon 10, more preferably three or more, and preferably eight or fewer, and more preferably six or fewer. Furthermore, in this case, it is preferable that the circumferential spacing of the protrusions 16 is longer than the circumferential length of a single protrusion 16. In Figures 2 and 4, linearly extending protrusions 16 are provided at three locations in the circumferential direction of the straight tube portion 13 of the balloon 10.

[0034] In the straight tube section 13 of the balloon 10, the projection 16 is preferably provided in a range of 1 / 2 or more of the longitudinal direction of the straight tube section 13, more preferably in a range of 2 / 3 or more, and even more preferably in a range of 3 / 4 or more. This makes it possible to create cracks over a wide area of ​​the constricted section when the balloon 10 is expanded.

[0035] The cross-sectional shape of the projection 16 is not particularly limited. For example, the cross-sectional shape perpendicular to the longitudinal direction of the projection 16 can be a polygon such as a triangle or quadrilateral, a partial circular shape such as a semicircle or sector, a roughly circular shape, a wedge shape, a convex shape, a spindle shape, or an irregular shape. Polygons include not only those with clearly defined corner vertices and straight sides, but also rounded polygons with rounded corners and those with at least a portion of their sides being curved. It is preferable that the projection 16 is formed to narrow towards the tip, and it is particularly preferable that it is formed in this manner in the cross-section perpendicular to the longitudinal direction.

[0036] In the straight tube portion 13 of the balloon 10, it is preferable that the wall thickness of the portion where the projection 16 is provided is thicker than the wall thickness of the portion where the projection 16 is not provided. This enhances the scoring function provided by the projection 16. The wall thickness of the portion of the straight tube portion 13 of the balloon 10 where the projection 16 is provided is preferably 1.5 times or more, more preferably 2.0 times or more, and even more preferably 2.5 times or more, than the wall thickness of the portion of the straight tube portion 13 of the balloon 10 where the projection 16 is not provided. There is no particular upper limit to the wall thickness of the portion of the straight tube portion 13 of the balloon 10 where the projection 16 is provided; for example, it may be 30 times or less, 20 times or less, or 10 times or less, the wall thickness of the portion of the straight tube portion 13 of the balloon 10 where the projection 16 is not provided.

[0037] The balloon 10 may have an inner projection (not shown) that protrudes radially inward from the inner surface of the balloon 10. The projection 16 and the inner projection may be located at the same position with respect to the longitudinal and circumferential directions of the balloon 10, and it is preferable that they are integrally molded, which may result in a part of the balloon 10 being formed to be thicker.

[0038] The present invention provides a suitable method for manufacturing a balloon catheter equipped with a balloon having protrusions on its surface as described above, and the manufacturing method of the present invention comprises the following steps. That is, the manufacturing method of a balloon catheter according to an embodiment of the present invention comprises the steps of: preparing a resin tubular body having protrusions on its surface (hereinafter referred to as the "resin tubular body preparation step"), preparing a first mold having a balloon-shaped lumen, wherein a recess is formed on the inner wall surface forming the lumen (hereinafter referred to as the "first mold preparation step"), and placing the resin tubular body in the lumen of the first mold, inflating the resin tubular body within the first mold, and causing the protrusions provided on the surface of the resin tubular body to enter the recess on the inner wall surface of the first mold. The present invention comprises a first molding step of obtaining an intermediate molded body formed in a balloon shape and having protrusions on its surface; a protrusion removal step of removing a portion of the protrusions of the intermediate molded body; a step of preparing a second mold having a balloon-shaped lumen and having recesses formed on the inner wall surface that form the lumen (hereinafter referred to as the "second mold preparation step"); and a second molding step of placing the intermediate molded body in the lumen of the second mold, inflating the intermediate molded body within the second mold, and causing the protrusions provided on the surface of the intermediate molded body to fit into the recesses on the inner wall surface of the second mold. According to the manufacturing method of the present invention, a balloon catheter can be easily manufactured in which protrusions are provided on the surface of the straight tube portion of the balloon, which is the part that expands significantly when the balloon is inflated.

[0039] The method for manufacturing a balloon catheter according to an embodiment of the present invention will be described in detail below with reference to Figures 5 to 21. Figure 5 shows a schematic diagram of the overall process for manufacturing a balloon catheter, Figures 6 to 9 show a schematic diagram of the resin tubular body preparation process and a perspective view and radial cross-sectional view (cross-sectional view perpendicular to the longitudinal direction) of the resin tubular body used therein, and Figures 10 to 21 show schematic diagrams of each process from the first mold preparation process to the second molding process. In Figure 5, the overall process for manufacturing a balloon catheter is shown with the resin tubular body as the focus, and a cross-sectional view along the longitudinal direction of the resin tubular body is shown. In Figures 7, 8 and 10 to 21, cross-sectional views along the longitudinal direction or perpendicular to the longitudinal direction of the mold and resin tubular body are shown in each process.

[0040] In the resin tubular body preparation step, a resin tubular body 21 (21A) having protrusions 23 on its surface is prepared (see Figures 5(A), 6, and 7). The resin tubular body 21A is a tubular object made of resin and has a lumen extending in the longitudinal direction. The resin constituting the resin tubular body 21A is described in the same way as the resin constituting the balloon 10 described above. Figure 7 shows a longitudinal vertical cross-sectional view of the enlarged diameter portion 24 of the resin tubular body 21A shown in Figure 6.

[0041] The resin tubular body 21 has a longitudinal direction and a radial direction. In the resin tubular body 21, the longitudinal direction corresponds to the direction of extension of the resin tubular body 21, and the radial direction is the direction perpendicular to the longitudinal direction, meaning the direction extending radially from the center of the resin tubular body 21 in a cross section perpendicular to the longitudinal direction of the resin tubular body 21. The resin tubular body 21 also has a circumferential direction, which is the direction along the outer circumference of the resin tubular body 21 in a cross section perpendicular to the longitudinal direction of the resin tubular body 21. The longitudinal direction, radial direction, and circumferential direction of the resin tubular body 21 correspond to the longitudinal direction, radial direction, and circumferential direction of the balloon 10, respectively.

[0042] The resin tubular body 21A preferably has projections 23 on the outer surface of the cylindrical portion 22 (see Figure 7). The projections 23 are provided so as to protrude radially outward from the outer surface of the cylindrical portion 22. The cross-sectional shape of the projections 23 is described in the above description of the cross-sectional shape of the projection 16 of the balloon 10, and preferably the projections 23 are formed to become narrower towards the tip. This makes it easier to improve the scoring function of the resulting balloon 10. In a longitudinal cross-section of the resin tubular body 21A, it is preferable that the resin tubular body 21A is formed to be thicker in the portion where the projections 23 are provided than in the other portions.

[0043] In the resin tubular body 21A, it is preferable that the projection 23 is made of the same resin as the cylindrical portion 22, and that the projection 23 and the cylindrical portion 22 are integrally molded. The cylindrical portion 22 of the resin tubular body 21A may have an inner layer and an outer layer, in which case it is preferable that the projection 23 is made of the same resin as the outer layer of the cylindrical portion 22. This prevents the projection 23 from unintentionally falling off during the manufacturing of the balloon 10. Alternatively, the projection 23 and the cylindrical portion 22 may be made of different resins, provided that the resin constituting the projection 23 and the resin constituting the cylindrical portion 22 have a certain degree of compatibility.

[0044] In the resin tubular body 21A, it is preferable that the projection 23 is provided so as to extend in the longitudinal direction. That is, it is preferable that the projection 23 is provided as a convex ridge extending in the longitudinal direction. This makes it easier to manufacture the resin tubular body 21A having projections 23 on its surface, and also makes it easier to get the projection 23 into the recess 39 of the inner wall surface 33 of the mold 31 when the resin tubular body 21A is expanded in the subsequent first molding step.

[0045] In the resin tubular body 21A, it is preferable that multiple projections 23 are provided at different positions in the circumferential direction. In this case, it is preferable that the projections 23 are arranged at approximately equal intervals in the circumferential direction of the resin tubular body 21A. It is preferable that the projections 23 are provided at two or more positions in the circumferential direction of the resin tubular body 21A, more preferably three or more, preferably eight or fewer, and more preferably six or fewer. In Figures 6 and 7, the projections 23 are provided so as to extend in the longitudinal direction, and the projections 23 are provided at three locations in the circumferential direction of the resin tubular body 21A.

[0046] In a longitudinal cross-section of the resin tubular body 21A, it is preferable that the projection 23 is formed such that its width narrows towards the tip. That is, it is preferable that the length of the projection 23 in the circumferential direction of the resin tubular body 21A is formed such that it becomes shorter towards the tip. In this case, the projection 23 may have a portion in which its width does not change towards the tip. By forming the projection 23 in this manner, the scoring function of the resulting balloon 10 can be enhanced.

[0047] It is preferable that the resin tubular body 21A has an enlarged diameter portion 24 in a part of its longitudinal direction. This makes it easier to blow mold the resin tubular body 21A around the enlarged diameter portion 24 in the subsequent first molding step. In the resin tubular body 21A, the outer diameter of the enlarged diameter portion 24 is preferably 1.2 times or more, more preferably 1.5 times or more, preferably 5.0 times or less, and more preferably 4.0 times or less than the outer diameter of the other parts. The outer diameter described herein refers to the maximum outer diameter passing through the centroid of the outer edge of the lumen in a vertical cross-section in the longitudinal direction of the resin tubular body 21A.

[0048] Preferably, the resin tubular body 21A has protrusions 23 on the surface of the enlarged diameter portion 24, as well as on the surface of portions other than the enlarged diameter portion 24. More preferably, as shown in Figure 5(A), the resin tubular body 21A has a first section 25, a second section 26, and a third section 27 from one side in the longitudinal direction, with the enlarged diameter portion 24 formed in the second section 26, and the protrusions 23 provided in the first section 25, the second section 26, and the third section 27.

[0049] To form a resin tubular body 21A having an enlarged diameter portion 24 in a part of its longitudinal direction, as shown in Figure 8, the resin tubular body preparation step preferably includes a step of preparing a straight tubular resin tubular body 21 (21P) having a first section 25, a second section 26, and a third section 27 from one side in the longitudinal direction and having protrusions 23 on its surface (hereinafter referred to as the "straight tubular resin tubular body preparation step") and a step of heating the straight tubular resin tubular body 21P to stretch the first section 25 and the third section 27 in the longitudinal direction to obtain a resin tubular body 21A having an enlarged diameter portion 24 in the second section 26 (hereinafter referred to as the "stretching step"). Figure 9 shows a perspective view of the straight tubular resin tubular body 21P, and the longitudinal vertical cross-sectional view of the straight tubular resin tubular body 21P is the same as the longitudinal vertical cross-sectional view of the enlarged diameter portion 24 of the resin tubular body 21A shown in Figure 7.

[0050] The resin tubular body 21P has a lumen extending in the longitudinal direction. The resin tubular body 21P can be manufactured by extrusion molding, injection molding, etc., and is preferably manufactured by extrusion molding. This facilitates mass production of the resin tubular body 21P and can increase the production efficiency of balloon catheters. The resin tubular body 21P can be used as a precursor for parison used in blow molding. It is preferable that the portion of the resin tubular body 21P provided with the projection 23 is formed to be thicker than the other portions.

[0051] The outer diameter of the resin tubular body 21P and the size of the projection 23 can be appropriately set according to the desired size and shape of the balloon 10 to be manufactured. Preferably, the resin tubular body 21P is constructed with projections 23 on the outer surface of the cylindrical portion 22, similar to the resin tubular body 21A. The outer diameter of the cylindrical portion 22 of the resin tubular body 21P, i.e., the outer diameter of the resin tubular body 21P excluding the projection 23, should be approximately 0.1 mm to 5.0 mm. The wall thickness of the cylindrical portion 22 of the resin tubular body 21P, i.e., the wall thickness of the resin tubular body 21P other than the portion on which the projection 23 is provided, should be approximately 0.03 mm to 2.0 mm. The height (radial length) of the projection 23 of the resin tubular body 21P, i.e., the height of the projection 23 relative to the outer surface of the cylindrical portion 22 of the resin tubular body 21P, should be approximately 0.03 mm to 2.0 mm.

[0052] As shown in Figure 7, the resin tubular body 21P preferably has a projection L1 of 0.05 times or more the outer diameter of the cylindrical portion 22, more preferably 0.1 times or more, even more preferably 0.2 times or more, preferably 1.0 times or less, more preferably 0.8 times or less, and even more preferably 0.5 times or less. If the resin tubular body 21P is formed in this manner, it becomes easier to mold the intermediate molded body 41 having the projection 23 in the subsequent first molding step, and it also becomes easier to remove the projection 23 from the intermediate molded body 41 in the projection removal step.

[0053] The height L1 of the projection 23 is preferably 0.5 times or more the width L2 of the base of the projection 23, more preferably 0.7 times or more, even more preferably 0.9 times or more, and preferably 3.0 times or less, more preferably 2.5 times or less, and even more preferably 2.0 times or less. If the projection 23 is formed in this manner, it becomes easier to mold the intermediate molded body 41 having the projection 23 in the first molding step, and it also becomes easier to remove the projection 23 from the intermediate molded body 41 in the projection removal step. From the viewpoint of forming a sharper projection 16 of the resulting balloon 10, the height L1 of the projection 23 is preferably 1.0 times or more the width L2 of the base of the projection 23, more preferably 1.1 times or more, and even more preferably 1.2 times or more. The height L1 of the projection 23 refers to the length of the projection 23 that protrudes radially relative to the outer surface of the cylindrical portion 22, and the width L2 of the base of the projection 23 refers to the length in the circumferential direction of the resin tubular body 21P at the point where the projection 23 contacts the outer surface of the cylindrical portion 22.

[0054] The descriptions above regarding the outer diameter of the resin tubular body 21P and the size of the protrusions 23 can also be applied to the outer diameter of the enlarged portion 24 and the protrusions 23 of the resin tubular body 21A. Furthermore, the descriptions regarding the shape and arrangement of the protrusions 23 of the resin tubular body 21A can also be applied to the protrusions 23 of the resin tubular body 21P.

[0055] The resin tubular body 21P preferably has protrusions 23 on the surface of each section from the first section 25 to the third section 27. In the resin tubular body 21P, the first section 25 and the third section 27 can be sections that are stretched in the longitudinal direction during the stretching process, while the second section 26 can be a section that is not stretched in the longitudinal direction during the stretching process. The length of each section can be appropriately set according to the manufacturing conditions and the size of the resulting balloon 10.

[0056] The projection 23 may be provided so as to extend intermittently in the longitudinal direction from the first section 25 to the third section 27, but it is preferable that it extends continuously in the longitudinal direction from the first section 25 to the third section 27 of the resin tubular body 21P. Furthermore, it is preferable that the cross-sectional shape perpendicular to the longitudinal direction of the resin tubular body 21P is substantially uniform in the longitudinal direction from the first section 25 to the third section 27.

[0057] In the stretching process, the first section 25 and the third section 27 of the resin tubular body 21P are heated to a temperature above the glass transition temperature of the constituent resin of the resin tubular body 21P, while the second section 26 is not heated, or is heated below the glass transition temperature of the constituent resin of the resin tubular body 21P, thereby selectively stretching the first section 25 and the third section 27 in the longitudinal direction. The first section 25 and the third section 27 are stretched in the longitudinal direction by heating the resin tubular body 21P and pulling the resin tubular body 21P from one or both sides in the longitudinal direction. Heating of the resin tubular body 21P can be done by known heating means such as a heater or hot air. From the viewpoint of selectively heating the first section 25 and the third section 27, it is preferable to heat the resin tubular body 21P from the outside. In the stretching process, by stretching the first section 25 and the third section 27 of the resin tubular body 21P in the longitudinal direction, the resulting resin tubular body 21A will have an outer diameter of the second section 26 that is larger than the outer diameters of the first section 25 and the third section 27, and an enlarged diameter section 24 can be formed in the second section 26.

[0058] In the first mold preparation step, a first mold 31 is prepared for pre-molding the resin tubular body 21A into a balloon shape in the first molding step (see Figure 10). The first mold 31 has a balloon-shaped lumen 32 that extends in the axial direction, and a recess 39 is formed in the inner wall surface 33 that forms the lumen 32. One side of the first mold 31 in the axial direction is referred to as the proximal side, and the other side as the distal side. The axial direction of the first mold 31 corresponds to the longitudinal direction of the resin tubular body 21. The first mold 31 also has a radial direction and a circumferential direction that correspond to the radial direction and circumferential direction of the resin tubular body 21, respectively. Hereinafter, the axial direction of the first mold 31 will be referred to as the "first axial direction".

[0059] The first mold 31 has a lumen 32 extending in the first axial direction, and the inner wall surface 33 forming the lumen 32 includes a first straight pipe forming section 36, a first proximal tapered section 35 located proximal to the first straight pipe forming section 36 and whose inner diameter decreases as it moves away from the first straight pipe forming section 36, a first proximal sleeve forming section 34 located proximal to the first proximal tapered section 35, and a first The first mold 31 has a first distal tapered section 37 whose inner diameter decreases as it moves away from the straight pipe forming section 36, and a first distal sleeve forming section 38 located distal to the first distal tapered section 37. Recesses 39 are formed in the inner wall surfaces 33 of the first straight pipe forming section 36, the first proximal tapered section 35, the first distal tapered section 37, the first proximal sleeve forming section 34, and the first distal sleeve forming section 38. Hereinafter, the recess formed in the inner wall surface 33 of the first mold 31 will be referred to as the "first recess".

[0060] In the first mold 31, it is preferable that the inner wall surface 33 of the first straight pipe forming section 36 forms a substantially cylindrical internal space, and that the inner diameter is largest in the first straight pipe forming section 36. The first proximal tapered section 35 is connected to the proximal end of the first straight pipe forming section 36 and is formed such that its inner diameter decreases as it moves away from the first straight pipe forming section 36, and it is preferable that the inner wall surface 33 of the first proximal tapered section 35 forms a truncated conical internal space. The first distal tapered section 37 is connected to the distal end of the first straight pipe forming section 36 and is formed such that its inner diameter decreases as it moves away from the first straight pipe forming section 36, and it is preferable that the inner wall surface 33 of the first distal tapered section 37 forms a truncated conical internal space. The first proximal sleeve forming portion 34 is connected to the proximal end of the first proximal tapered portion 35, and it is preferable that the inner wall surface 33 of the first proximal sleeve forming portion 34 forms a substantially cylindrical internal space. The inner diameter of the first proximal sleeve forming portion 34 is preferably substantially the same as the inner diameter at the connection between the first proximal sleeve forming portion 34 and the first proximal tapered portion 35. The first distal sleeve forming portion 38 is connected to the distal end of the first distal tapered portion 37, and it is preferable that the inner wall surface 33 of the first distal sleeve forming portion 38 forms a substantially cylindrical internal space. The inner diameter of the first distal sleeve forming portion 38 is preferably substantially the same as the inner diameter at the connection between the first distal sleeve forming portion 38 and the first distal tapered portion 37.

[0061] The first mold 31 is preferably made of metal. Examples of metals that make up the first mold 31 include iron, copper, aluminum, and alloys thereof (for example, stainless steel, brass, duralumin, etc.). If the first mold 31 is made of metal, in the first molding process, heating the first mold 31 from the outside makes it easier to uniformly heat the resin tubular body 21A placed in the lumen 32 of the first mold 31, and makes it easier to mold the resin tubular body 21A to match the shape of the lumen 32 of the first mold 31. The first mold 31 can be heated by known heating means such as a heater, hot air, or electromagnetic induction heating.

[0062] Preferably, the first mold 31 is composed of multiple segments. That is, it is preferable that multiple mold segments are combined to form the first mold 31. This makes it easier to place the resin tubular body 21A in the lumen 32 of the first mold 31, and to remove the intermediate molded body 41 from the first mold 31 after the resin tubular body 21A is expanded inside the first mold 31 in the first molding process to form an intermediate molded body 41.

[0063] The first mold 31 may be divided into multiple sections in the circumferential direction or into multiple sections in the first axial direction. That is, the first mold 31 may be formed by arranging multiple mold segments in the circumferential direction or by arranging multiple mold segments in the first axial direction. In the former case, for example, multiple half-pipe shaped mold segments can be arranged in the circumferential direction to form at least a part of the first axial direction of the first mold 31. In the latter case, for example, as shown in Figure 10, the first mold 31 can be formed by arranging mold segment 31A, which gives the first proximal sleeve forming section 34, mold segment 31B, which gives the first proximal taper forming section 35, mold segment 31C, which gives the first straight pipe forming section 36, mold segment 31D, which gives the first distal taper forming section 37, and mold segment 31E, which gives the first distal sleeve forming section 38, in this order in the first axial direction. By configuring the first mold 31 in this way, intermediate molded bodies 41 of various shapes and sizes can be manufactured in the first molding process by replacing each mold segment. The first mold 31 may be formed by arranging a plurality of mold segments in the circumferential direction and a plurality of mold segments in the first axial direction.

[0064] The first mold 31 has a first straight tube forming section 36, a first proximal taper forming section 35, a first distal taper forming section 37, a first proximal sleeve forming section 34, and a first distal sleeve forming section 38, with the inner wall surface 33 of the first straight tube forming section 36 being formed to be recessed radially outward in the first recess 39. The first recess 39 is provided to allow the projections 23 on the surface of the resin tubular body 21A to enter the first recess 39 when the resin tubular body 21A is expanded in the first molding process. This prevents the projections 23 on the surface of the resin tubular body 21A from being crushed and deformed by the inner wall surface 33 of the first mold 31 when the resin tubular body 21A is expanded in the first mold 31, making it easier to remove a portion of the projections 23 of the intermediate molded body 51 in the subsequent projection removal process.

[0065] In the first straight tube forming section 36, the first recess 39 is preferably provided as a groove extending in the first axial direction of the first mold 31. This makes it easier to insert the projection 23 into the first recess 39 when the resin tubular body 21A is expanded in the first molding process. More specifically, in the first molding process, the position of the projection 23 provided on the surface of the resin tubular body 21A and the position of the first recess 39 formed in the first straight tube forming section 36 of the first mold 31 are aligned in the circumferential direction, and the resin tubular body 21A is expanded in this state. This makes it easier to insert the projection 23 provided on the surface of the resin tubular body 21A into the first recess 39 of the first mold 31, even if the resin tubular body 21A is stretched in the longitudinal direction. The first recess 39 is preferably provided so as to extend continuously in the first axial direction from the first proximal sleeve forming section 34 to the first distal sleeve forming section 38.

[0066] The cross-sectional shape of the first recess 39 is not particularly limited, but it is preferable that the first recess 39 has a portion that narrows in width toward the radially outward direction. Examples of such cross-sectional shapes of the first recess 39 include a V-shape and a U-shape. When the first recess 39 is formed as a groove, it is formed as a V-shaped groove or a U-shaped groove. Figures 11 and 12 show examples of the XI-XI cross-sectional view of the first mold 31 shown in Figure 10, with Figure 11 showing an example in which the first recess 39 has a U-shaped cross-section, and Figure 12 showing an example in which the first recess 39 has a V-shaped cross-section. By forming the first recess 39 in this way, it becomes easier to form a balloon 10 having a sharp projection 16 on its outer surface.

[0067] As shown in Figure 11, it is preferable that the first recess 39 has a portion near its entrance that maintains or widens in width radially outward. For example, it is preferable that the first recess 39 has a portion in at least a part of the radially inner 1 / 2 of the region of the first recess 39 that maintains or widens in width radially outward. This makes it less likely for the projection 23 provided on the resin tubular body 21A to come into contact with the first recess 39 when it is inserted into the first recess 39 during the first molding process, thereby preventing the projection 23 from deforming or cracking. Preferably, the first recess 39 has a portion in at least a part of the radially inner 1 / 2 of the region of the first recess 39 that maintains or widens in width radially outward, and the portion that maintains or widens in width radially outward is formed to have a length of at least 1 / 3 of the radial length of the first recess 39.

[0068] In the inner wall surface 33 of the first mold 31, it is preferable that multiple first recesses 39 are provided at different positions in the circumferential direction. In this case, it is preferable that the first recesses 39 are arranged at approximately equal intervals in the circumferential direction on the inner wall surface 33 of the first mold 31. It is preferable that the first recesses 39 are provided at two or more positions in the circumferential direction on the inner wall surface 33 of the first mold 31, more preferably three or more, and preferably eight or fewer, and even more preferably six or fewer. Furthermore, in the vertical cross-section in the first axial direction of the first straight tube forming section 36, it is preferable that the spacing (separation length along the inner wall surface 33) of the multiple first recesses 39 arranged in the circumferential direction is longer than the maximum length of the first recess 39 in the circumferential direction. In Figures 11 and 12, the first recesses 39 are provided at three locations in the circumferential direction on the inner wall surface 33 of the first mold 31, which corresponds to the number of protrusions 23 provided on the surface of the resin tubular body 21A in the circumferential direction.

[0069] The depth L3 of the first recess 39, that is, the radial length from the inner wall surface 33 of the first mold 31 to the bottom of the first recess 39, is preferably longer than the height L1 of the projection 23 provided on the surface of the resin tubular body 21A, that is, the radial length of the projection 23 of the resin tubular body 21A (see Figures 7, 11, and 12). This prevents the tip of the projection 23 from hitting the bottom of the first recess 39 when the projection 23 provided on the resin tubular body 21A is inserted into the first recess 39 during the first molding process. It also prevents the projection 23 from cracking when it hits the bottom of the first recess 39. As a result, it becomes easier to form a balloon 10 having a sharp projection 16 on its outer surface. The depth L3 of the first recess 39 is preferably 1.1 times or more the height L1 of the projection 23, more preferably 1.2 times or more, even more preferably 1.3 times or more, and preferably 3.0 times or less, more preferably 2.5 times or less, and even more preferably 2.0 times or less. The bottom of the first recess 39 refers to the radially outer portion of the first recess 39 relative to the first mold 31.

[0070] The width L4 (length in the circumferential direction) of the entrance to the first recess 39 in a cross section perpendicular to the first axial direction of the first mold 31 is preferably the same as or longer than the width L2 of the base of the projection 23 in a cross section perpendicular to the longitudinal direction of the resin tubular body 21A (see Figures 7, 11, and 12). The width L4 of the entrance to the first recess 39 is preferably 1.0 times or more, more preferably 1.05 times or more, even more preferably 1.1 times or more, and preferably 2.0 times or less, more preferably 1.8 times or less, and even more preferably 1.5 times or less of the width L2 of the base of the projection 23 of the resin tubular body 21A. This makes it easier to insert the projection 23 provided on the resin tubular body 21A into the first recess 39 during the first molding process.

[0071] In the first molding process, as shown in Figure 13, a resin tubular body 21A is placed in the lumen 32 of the first mold 31, and the resin tubular body 21A is inflated to obtain an intermediate molded body 41 having a balloon shape and protrusions 23 on its surface. The intermediate molded body 41 has a proximal sleeve portion 42, a proximal tapered portion 43, a straight tube portion 44, a distal tapered portion 45, and a distal sleeve portion 46 from one side in the longitudinal direction, and the outer diameter of the proximal tapered portion 43 and the distal tapered portion 45 decreases as they move away from the straight tube portion 44. The longitudinal direction of the intermediate molded body 41 corresponds to the longitudinal direction of the resin tubular body 21. The intermediate molded body 41 also has a radial direction and a circumferential direction that correspond to the radial direction and circumferential direction of the resin tubular body 21, respectively.

[0072] When placing the resin tubular body 21A in the lumen 32 of the first mold 31, it is preferable that the portion of the resin tubular body 21A including the enlarged diameter portion 24 is positioned in the lumen 32 of the first mold 31. This makes it easier to mold the resin tubular body 21A to match the shape of the lumen 32 of the first mold 31A. Specifically, it is preferable that the enlarged diameter portion 24, i.e., the second section 26, is positioned in the range from the first proximal taper forming portion 35 to the first distal taper forming portion 37 of the first mold 31 with respect to the first axial direction of the first mold 31, and more preferably that it is positioned only in the first straight pipe forming portion 36 of the first mold 31. The first section 25 of the resin tubular body 21A is preferably arranged in the first proximal sleeve forming section 34 and the first proximal taper forming section 35 with respect to the first axial direction of the first mold 31, and more preferably arranged in the first proximal sleeve forming section 34, the first proximal taper forming section 35 and the first straight pipe forming section 36. The third section 27 of the resin tubular body 21A is preferably arranged in the first distal sleeve forming section 38 and the first distal taper forming section 37 with respect to the first axial direction of the first mold 31, and more preferably arranged in the first distal sleeve forming section 38, the first distal taper forming section 37 and the first straight pipe forming section 36. Furthermore, it is preferable that the outer diameter of the enlarged portion 24 of the resin tubular body 21A, i.e., the outer diameter of the second section 26, is smaller than the inner diameter of the first straight pipe forming portion 36 of the first mold 31; the outer diameter of the first section 25 of the resin tubular body 21A is smaller than the inner diameters of the first proximal sleeve forming portion 34 and the first proximal taper forming portion 35 of the first mold 31; and the outer diameter of the third section 27 of the resin tubular body 21A is smaller than the inner diameters of the first distal sleeve forming portion 38 and the first distal taper forming portion 37 of the first mold 31.

[0073] Preferably, a portion of the first section 25 and a portion of the third section 27 of the resin tubular body 21A are positioned outside the lumen 32 of the first mold 31, and the first section 25 and the third section 27 are held outside the first mold 31 by a fixing device. This allows the resin tubular body 21A to be positioned approximately at the center of the lumen 32 of the first mold 31 in a vertical cross-section in the first axial direction of the first mold 31, as shown in Figure 14, making it easier to uniformly expand the resin tubular body 21A in the radial direction during the first molding process. Figure 14 shows an example in which the resin tubular body 21A is positioned in the lumen 32 of the first mold 31 as shown in Figure 11.

[0074] The longitudinal length of the resin tubular body 21A from the first section 25 to the third section 27 used in the first molding process is preferably 1.1 times or more, more preferably 1.2 times or more, and even more preferably 1.3 times or more, the length in the first axial direction of the lumen 32 of the first mold 31. This makes it easier to hold a portion of the first section 25 and a portion of the third section 27 of the resin tubular body 21A outside the lumen 32 of the first mold 31. There is no particular upper limit to the longitudinal length of the resin tubular body 21A from the first section 25 to the third section 27 used in the first molding process, but from the viewpoint of reducing the amount of resin used when manufacturing the balloon 10, it is preferably 10 times or less, more preferably 8 times or less, and even more preferably 5 times or less, the length in the first axial direction of the lumen 32 of the first mold 31.

[0075] After placing the resin tubular body 21A in the lumen 32 of the first mold 31, the resin tubular body 21A is expanded to contact the inner wall surface 33 of the first mold 31, thereby obtaining an intermediate molded body 41 (41A) having a straight tube portion 44 in contact with the first straight tube forming portion 36, a proximal tapered portion 43 in contact with the first proximal tapered portion 35, a proximal sleeve portion 42 in contact with the first proximal sleeve forming portion 34, a distal tapered portion 45 in contact with the first distal tapered portion 37, and a distal sleeve portion 46 in contact with the first distal sleeve forming portion 38. At this time, the projections 23 provided on the surface of the resin tubular body 21A are inserted into the first recess 39 of the first mold 31, thereby obtaining an intermediate molded body 41A formed in a balloon shape with projections 23 on its surface.

[0076] In the first molding process, it is preferable to heat the resin tubular body 21A and introduce a fluid into the lumen of the resin tubular body 21A to expand it. The resin tubular body 21A can be heated by heating the first mold 31 with the resin tubular body 21A placed in the lumen 32 of the first mold 31.

[0077] It is preferable that the heating temperature be above the glass transition temperature of the resin constituting the resin tubular body 21A. If the first mold 31 is formed from a plurality of mold segments arranged in the first axial direction, for example, the mold segment in which the second section 26 of the resin tubular body 21A is located may be heated to a higher temperature, thereby preferentially heating and expanding the second section 26 of the resin tubular body 21A. For example, in the example shown in Figure 13, the mold segment 31C in which the second section 26 of the resin tubular body 21A is located may be heated to a higher temperature than mold segments 31A, 31B, 31D, and 31E, or mold segments 31B to 31D may be heated to a higher temperature than mold segments 31A and 31E.

[0078] The fluid introduced into the lumen of the resin tubular body 21A may be a gas such as air or nitrogen gas, or a liquid such as water. By introducing fluid into the lumen of the resin tubular body 21A, the inside of the resin tubular body 21A is pressurized, causing the resin tubular body 21A to expand, and thus enabling so-called blow molding. Pressurization of the inside of the resin tubular body 21A can be performed, for example, by closing one end of the resin tubular body 21A in the longitudinal direction and introducing fluid from the other end, or by introducing fluid from both ends of the resin tubular body 21A in the longitudinal direction.

[0079] When the resin tubular body 21A is expanded in the first mold 31, the pressure inside the lumen of the resin tubular body 21A is preferably, as a gauge pressure, 1.0 MPa or more, more preferably 1.5 MPa or more, even more preferably 2.0 MPa or more, and preferably 6.0 MPa or less, and more preferably 5.5 MPa or less.

[0080] When the resin tubular body 21A is expanded in the first molding process, it is preferable that the second section 26 of the resin tubular body 21A abuts against at least the first proximal tapered section 35, the first straight section 36, and the first distal tapered section 37 of the first mold 31, and the second section 26 may further abut against the first proximal sleeve forming section 34 and / or the first distal sleeve forming section 38. When the resin tubular body 21A is expanded, the first section 25 may abut against the first proximal sleeve forming section 34, and the third section 27 may abut against the first distal sleeve forming section 38.

[0081] In the first molding step, it is preferable to expand the second section 26 of the resin tubular body 21A in the longitudinal and radial directions. This makes it easier to mold the resin tubular body 21A to match the shape of the lumen 32 of the first mold 31. In order to expand the second section 26 of the resin tubular body 21A in the longitudinal direction, it is preferable to heat the second section 26 and stretch it in the longitudinal direction while introducing a fluid into the lumen of the resin tubular body 21A to expand the second section 26. In the first molding step, in addition to the second section 26, the first section 25 and the third section 27 may also be expanded in the longitudinal and radial directions.

[0082] In the first molding process, the second section 26 may be stretched longitudinally within the first mold 31, and then expanded longitudinally and radially. This makes it easier to bring the second section 26 of the resin tubular body 21A into contact with the first proximal sleeve forming section 34 and the first distal sleeve forming section 38 of the first mold 31. Furthermore, in the straight tube section 13 of the balloon 10 obtained in this way, the orientation direction of the polymer constituting the resin tends to be oriented longitudinally. That is, in the straight tube section 13, the orientation direction of the polymer constituting the resin has a greater proportion of components oriented longitudinally. In this case, when the balloon 10 ruptures, it is more likely to rupture longitudinally in the straight tube section 13 than circumferentially. Therefore, even if the balloon 10 ruptures due to overpressure or the like during use, the balloon 10 will rupture safely, and it is less likely that fragments of the balloon 10 will damage the inner wall of the body cavity.

[0083] In the first molding step, the resin tubular body 21A is expanded in the first mold 31, causing the protrusions 23 on the surface of the resin tubular body 21A to enter the first recess 39 of the first mold 31. This yields an intermediate molded body 41A formed in a balloon shape with protrusions 23 on its surface. Preferably, the intermediate molded body 41A has protrusions 23 on the surfaces of the proximal sleeve portion 42, the proximal tapered portion 43, the straight tube portion 44, the distal tapered portion 45, and the distal sleeve portion 46.

[0084] When the resin tubular body 21A is expanded and the projection 23 is inserted into the first recess 39 of the first mold 31, it is preferable that the projection 23 does not come into contact with the bottom of the first recess 39, as shown in Figure 15. This makes it less likely that the projection 23 of the intermediate molded body 41A will be unintentionally distorted or crushed. Therefore, it becomes easier to form an intermediate molded body 41A having a sharp projection 23 on its outer surface. Figure 15 shows an example in which an intermediate molded body 41A is formed by blow molding using the first mold 31 shown in Figure 11.

[0085] It is preferable to include a step of removing the intermediate molded body 41A from the first mold 31 after the first molding step (hereinafter referred to as the "first mold removal step"). In the first mold removal step, the first mold 31 may be removed from the intermediate molded body 41A while the intermediate molded body 41A is fixed, or the intermediate molded body 41A may be removed from the first mold 31 while the first mold 31 is fixed. In the first mold removal step, it is preferable to lower the temperature of the first mold 31 to below the glass transition temperature of the resin constituting the intermediate molded body 41A before removing the intermediate molded body 41A from the first mold 31.

[0086] In the first mold removal step, it is preferable to remove the intermediate molded body 41A from the first mold 31 before the projection 23 reaches the bottom of the first recess 39 of the first mold 31. This makes it less likely that the projection 23 of the intermediate molded body 41A after blow molding will be unintentionally distorted or crushed.

[0087] The intermediate molded body 41A obtained as described above is then subjected to a protrusion removal process, in which a portion of the protrusions 23 of the intermediate molded body 41A is removed. The protrusion removal process is preferably performed after the first mold removal process. In the protrusion removal process, as shown in Figure 16, the protrusions 23 present on the proximal sleeve portion 42 and the distal sleeve portion 46 of the intermediate molded body 41A are removed. Since the proximal sleeve portion 42 and the distal sleeve portion 46 are formed in a substantially straight tubular shape, the protrusions 23 present on the proximal sleeve portion 42 and the distal sleeve portion 46 can be easily removed by applying a cutting means such as a cutter to the surfaces of the proximal sleeve portion 42 and the distal sleeve portion 46. The protrusion removal process yields an intermediate molded body 41 (41B) from which the protrusions 23 present on the proximal sleeve portion 42 and the distal sleeve portion 46 have been removed.

[0088] In the protrusion removal process, it is sufficient to remove at least a portion of the protrusions 23 present in the proximal sleeve portion 42 and distal sleeve portion 46 of the intermediate molded body 41A. Preferably, all of the protrusions 23 present in the proximal sleeve portion 42 and distal sleeve portion 46 that will be placed in the second mold 51 in the subsequent second molding process are removed. On the other hand, it is preferable that the protrusions 23 present in the straight tube portion 44 are not removed in the protrusion removal process. It is also preferable that the protrusions 23 present in the proximal tapered portion 43 and distal tapered portion 45 are not removed in the protrusion removal process, however, it is permissible to remove the protrusions 23 present in the proximal tapered portion 43 near the proximal sleeve portion 42 (for example, in the proximal 1 / 3 range of the proximal tapered portion 43) and it is permissible to remove the protrusions 23 present in the distal tapered portion 46 near the distal sleeve portion 47 (for example, in the distal 1 / 3 range of the distal tapered portion 46).

[0089] In the protrusion removal process, the protrusions 23 can be removed using known cutting means such as a cutter, laser light, or heat wire. In the proximal sleeve portion 42 and the distal sleeve portion 46, the protrusions 23 provided on the surface of the intermediate molded body 41A can be easily removed by applying a cutting means such as a cutter to the intermediate molded body 41A and moving the cutting means in the longitudinal direction relative to the intermediate molded body 41A. In the protrusion removal process, the position of the intermediate molded body 41A may be fixed and the protrusions 23 may be removed by moving a cutting means such as a cutter in the longitudinal direction of the intermediate molded body 41A, or the cutting means such as a cutter may be fixed and installed and the intermediate molded body 41A may be moved in the longitudinal direction to remove the protrusions 23. Alternatively, the protrusions 23 may be removed by moving the intermediate molded body 41A in one longitudinal direction while moving the cutting means such as a cutter in the other longitudinal direction of the intermediate molded body 41A.

[0090] In the projection removal step, the entire projection 23 in the height direction (i.e., the radial direction of the intermediate molded body 41A) may be removed, or only a portion of the projection 23 in the height direction may be removed. Preferably, at least 1 / 3 of the projection 23 in the height direction is removed, more preferably at least 1 / 2, and even more preferably at least 2 / 3. This makes it easier to form a smooth surface on the portion originating from the proximal sleeve portion 42 and the distal sleeve portion 46 when the projection 23, from which a portion in the height direction has been removed, is pressed against the inner wall surface 53 of the second mold 51 in the subsequent second molding step, as the projection 23 is crushed. In this case, a smooth projection that is lower in height than the projection 16 of the straight pipe portion 13 is formed on the portion originating from the proximal sleeve portion 42 and the distal sleeve portion 46, and an inner projection may be formed at the same position in the longitudinal and circumferential directions.

[0091] In the intermediate molded body 41B from which a portion of the protrusion 23 has been removed in the protrusion removal process, as shown in Figure 17, it is preferable that the height L5 of the protrusion 23 in the straight tube section 44 is 0.3 times or more the width L6 of the base, more preferably 0.5 times or more, even more preferably 0.7 times or more, and also preferably 3.0 times or less, more preferably 2.5 times or less, and even more preferably 2.0 times or less. This makes it easier to mold the balloon molded body 61 having the protrusion 23 in the second molding process, and also makes it easier to make the protrusion 23 sharp.

[0092] In the projection removal process, the projections 23 of the proximal sleeve portion 42 and the distal sleeve portion 46 are removed from the intermediate molded body 41B. Next, in the second mold preparation process, a second mold 51 having a balloon-shaped lumen 52 is prepared, and in the second molding process, the intermediate molded body 41B is blow-molded using the second mold 51 to obtain a balloon molded body 61.

[0093] In the second mold preparation step, a second mold 51 is prepared for the final molding of the intermediate molded body 41B into a balloon shape that matches the balloon 10 in the second molding step (see Figure 18). The second mold 51 has a balloon-shaped lumen 52 that extends in the axial direction, and a recess 59 is formed in the inner wall surface 53 that forms the lumen 52. One side of the second mold 51 in the axial direction is referred to as the proximal side, and the other side as the distal side. The axial direction of the second mold 51 corresponds to the longitudinal direction of the intermediate molded body 41B. The second mold 51 also has a radial direction and a circumferential direction that correspond to the radial direction and circumferential direction of the intermediate molded body 41B, respectively. Hereinafter, the axial direction of the second mold 51 will be referred to as the "second axial direction".

[0094] The second mold 51 has a lumen 52 extending in the second axial direction, and the inner wall surface 53 forming the lumen 52 has a second straight pipe forming section 56, a second proximal tapered section 55 located proximal to the second straight pipe forming section 56 and whose inner diameter decreases as it moves away from the second straight pipe forming section 56, a second proximal sleeve forming section 54 located proximal to the second proximal tapered section 55, a second distal tapered section 57 located distal to the second straight pipe forming section 56 and whose inner diameter decreases as it moves away from the second straight pipe forming section 56, and a second distal sleeve forming section 58 located distal to the second distal tapered section 57, and a recess 59 is formed in the inner wall surface 53 of the second straight pipe forming section 56. Hereinafter, the recess formed in the inner wall surface 53 of the second mold 51 will be referred to as the "second recess".

[0095] For details of the constituent materials of the second mold 51 and the shapes of the second straight pipe forming section 56, the second proximal taper forming section 55, the second distal taper forming section 57, the second proximal sleeve forming section 54, and the second distal sleeve forming section 58, please refer to the description of the first mold 31 above. The second mold 51 may be formed from multiple mold segments, and as shown in Figure 18, it may be formed from mold segment 51A that gives the second proximal sleeve forming section 54, mold segment 51B that gives the second proximal taper forming section 55, mold segment 51C that gives the second straight pipe forming section 56, mold segment 51D that gives the second distal taper forming section 57, and mold segment 51E that gives the second distal sleeve forming section 58. For details of the mold segments of the second mold 51, please refer to the description of the first mold 31 above. In the reference to the description of the first mold 31, by reading "first" as "second", it will be considered the description of the second mold 51.

[0096] In the second mold 51, the second axial length of the second straight pipe forming section 56 is longer than the first axial length of the first straight pipe forming section 36 of the first mold 31, and the inner diameter of the second straight pipe forming section 56 is larger than the inner diameter of the first straight pipe forming section 56 of the first mold 31. With the second mold 51 formed in this way, the intermediate molded body 41B can be placed in the lumen 52 of the second mold 51. Preferably, in the second mold 51, the second axial length from the second proximal taper forming section 55 to the second distal taper forming section 57 is longer than the first axial length from the first proximal taper forming section 35 to the first distal taper forming section 37 of the first mold 31. Furthermore, it is preferable that the inner diameter of the second proximal sleeve forming portion 54 of the second mold 51 is larger than the inner diameter of the first proximal sleeve forming portion 34 of the first mold 31, and that the inner diameter of the second distal sleeve forming portion 58 is larger than the inner diameter of the first distal sleeve forming portion 38 of the first mold 31.

[0097] The second mold 51 has a second recess 59 on the inner wall surface 53 of the second straight pipe forming section 56. The inner wall surface 53 of the second straight pipe forming section 56 is formed to be recessed radially outward in the second recess 59. The second recess 59 is provided to allow the protrusions 23 provided on the surface of the intermediate molded body 41B to enter the second recess 59 when the intermediate molded body 41B is expanded in the second molding process. As a result, when the intermediate molded body 41B is expanded in the second mold 51, the protrusions 23 provided on the surface of the intermediate molded body 41B are not crushed by the inner wall surface 53 of the second mold 51, and a balloon 10 having protrusions 16 on the outer surface of the straight pipe section 13 can be formed.

[0098] In the second straight pipe forming section 56, the second recess 59 is preferably provided as a groove extending in the second axial direction of the second mold 51. This makes it easier to insert the projection 23 into the second recess 59 when the intermediate molded body 41B is expanded in the second molding process. Specifically, in the second molding process, the position of the projection 23 provided on the surface of the intermediate molded body 41B and the position of the second recess 59 formed in the second straight pipe forming section 56 of the second mold 51 are aligned in the circumferential direction, and the intermediate molded body 41B is expanded in this state, making it easier to insert the projection 23 provided on the surface of the intermediate molded body 41B into the second recess 59 of the second mold 51. When the second recess 59 is provided as a groove extending in the second axial direction, the length of the second recess 59 (groove) in the second axial direction is preferably 1 / 2 or more of the length of the second straight pipe forming section 56 in the second axial direction, more preferably 2 / 3 or more, and even more preferably 3 / 4 or more. It is particularly preferable that the second recess 59 (groove) is provided so as to extend over the entire second axial direction of the second straight pipe forming portion 56.

[0099] The second mold 51 may also be provided with a second recess 59 in the second tapered portion 55 and / or the second tapered portion 57, but it is preferable that the inner wall surface 53 of the second tapered portion 55 and the inner wall surface 53 of the second tapered portion 57 are not provided with a second recess 59. This makes it easier to form smooth surfaces for the proximal tapered portion 12 and distal tapered portion 14 of the resulting balloon 10. Furthermore, it is preferable that the inner wall surface 53 of the second sleeve forming portion 54 and the inner wall surface 53 of the second sleeve forming portion 58 are not provided with a second recess 59.

[0100] The cross-sectional shape of the second recess 59 is not particularly limited, but it is preferable that the second recess 59 has a portion that narrows in width toward the radially outward direction. Examples of such cross-sectional shapes of the second recess 59 include a V-shape and a U-shape. When the second recess 59 is formed as a groove, it is formed as a V-shaped groove or a U-shaped groove. Figure 19 shows an example of the XIX-XIX cross-sectional view of the second mold 51 shown in Figure 18, and shows an example in which a second recess 59 with a U-shaped cross-section is provided. By forming the second recess 59 in this way, it becomes easier to form a balloon 10 having a sharp projection 16 on its outer surface. For details of the cross-sectional shape of the second recess 59, refer to the description of the first recess 39 of the first mold 31 above.

[0101] In the inner wall surface 53 of the second mold 51, it is preferable that multiple second recesses 59 are provided at different positions in the circumferential direction. In this case, it is preferable that the second recesses 59 are arranged at approximately equal intervals in the circumferential direction on the inner wall surface 53 of the second mold 51. It is preferable that the second recesses 59 are provided at two or more positions in the circumferential direction on the inner wall surface 53 of the second mold 51, more preferably three or more, and preferably eight or fewer, and even more preferably six or fewer. Furthermore, in the vertical cross-section in the second axial direction of the second straight pipe forming section 56, it is preferable that the spacing (separation length along the inner wall surface 53) of the multiple second recesses 59 arranged in the circumferential direction is longer than the maximum length of the second recess 59 in the circumferential direction. In Figure 19, the second recesses 59 are provided at three locations in the circumferential direction on the inner wall surface 53 of the mold 51, which corresponds to the number of protrusions 23 provided on the surface of the intermediate molded body 41B in the circumferential direction.

[0102] The depth L7 of the second recess 59, that is, the radial length from the inner wall surface 53 of the second mold 51 to the bottom of the second recess 59, is preferably longer than the height L5 of the projection 23 provided on the surface of the intermediate molded body 41B, that is, the radial length of the projection 23 of the intermediate molded body 41B (see Figures 17 and 19). This prevents the tip of the projection 23 from hitting the bottom of the second recess 59 when the projection 23 provided on the intermediate molded body 41B is inserted into the second recess 59 during the second molding process. It also prevents the projection 23 from cracking when it hits the bottom of the second recess 59. As a result, it becomes easier to form a balloon 10 having a sharp projection 16 on its outer surface. The depth L7 of the second recess 59 is preferably 1.1 times or more, more preferably 1.2 times or more, still preferably 1.3 times or more, preferably 3.0 times or less, more preferably 2.5 times or less, and still preferably 2.0 times or less, of the height L5 of the protrusion 23 provided on the surface of the intermediate molded body 41B. The bottom of the second recess 59 refers to the radially outer portion of the second recess 59 relative to the second mold 51.

[0103] The width L8 (length in the circumferential direction) of the entrance to the second recess 59 in a cross section perpendicular to the second axial direction of the second mold 51 is preferably the same as or longer than the width L6 of the base of the projection 23 in a cross section perpendicular to the longitudinal direction of the intermediate molded body 41B (see Figures 17 and 19). The width L8 of the entrance to the second recess 59 is preferably 1.0 times or more, more preferably 1.05 times or more, even more preferably 1.1 times or more, and preferably 2.0 times or less, more preferably 1.8 times or less, and even more preferably 1.5 times or less of the width L6 of the base of the projection 23 of the intermediate molded body 41B. This makes it easier to insert the projection 23 provided on the intermediate molded body 41B into the second recess 59 during the second molding process.

[0104] In the second molding process, as shown in Figure 20, the intermediate molded body 41B, from which a portion of the protrusions 23 obtained in the protrusion removal process has been removed, is placed in the lumen 52 of the second mold 51, and the intermediate molded body 41B is inflated to obtain a balloon molded body 61 with protrusions 23 on its surface. The balloon molded body 61 has a shape corresponding to the balloon 10, and has a proximal sleeve portion 62, a proximal tapered portion 63, a straight portion 64, a distal tapered portion 65, and a distal sleeve portion 66, which correspond to the proximal sleeve portion 11, proximal tapered portion 12, straight tube portion 13, distal tapered portion 14, and distal sleeve portion 15 of the balloon 10, respectively. The balloon molded body 61 has a longitudinal direction corresponding to the longitudinal direction of the intermediate molded body 41B, and also has radial and circumferential directions corresponding to the radial and circumferential directions of the intermediate molded body 41B, respectively.

[0105] When placing the intermediate molded body 41B in the lumen 52 of the second mold 51, it is preferable that the intermediate molded body 41B has its proximal sleeve portion 42, proximal tapered portion 43, straight tube portion 44, distal tapered portion 45, and distal sleeve portion 46 positioned in the lumen 52 of the second mold 51. More specifically, it is preferable that the straight tube portion 44 of the intermediate molded body 41B be positioned only in the second straight tube forming portion 56 of the second mold 51 with respect to the second axial direction of the second mold 51. It is preferable that the proximal tapered portion 43, straight tube portion 44, and distal tapered portion 45 of the intermediate molded body 41B be positioned in the range from the second proximal tapered forming portion 55 to the second distal tapered forming portion 57 of the second mold 51 with respect to the second axial direction of the second mold 51, and more preferably that they be positioned only in the second straight tube forming portion 56 of the second mold 51. This makes it easier to mold the intermediate molded body 41B to match the shape of the lumen 52 of the second mold 51. Furthermore, it is preferable that the outer diameter of the straight pipe section 44 of the intermediate molded body 41B is smaller than the inner diameter of the second straight pipe forming section 56 of the second mold 51. It is also preferable that the outer diameters of the proximal tapered section 43, the straight pipe section 44, and the distal tapered section 45 of the intermediate molded body 41B are smaller than the inner diameter of the second straight pipe forming section 56 of the second mold 51.

[0106] Preferably, the length from the proximal end of the proximal tapered portion 43 to the distal end of the distal tapered portion 45 of the intermediate molded body 41B is shorter than the length from the midpoint between the proximal and distal ends of the second proximal tapered forming portion 55 of the second mold 51 to the midpoint between the proximal and distal ends of the second distal tapered forming portion 57. This makes it easier to mold the intermediate molded body 41B to match the shape of the lumen 52 of the second mold 51. More preferably, the length from the proximal end of the proximal tapered portion 43 to the distal end of the distal tapered portion 45 of the intermediate molded body 41B is shorter than the length in the second axial direction of the second straight tube forming portion 56 of the second mold 51.

[0107] The proximal sleeve portion 42 of the intermediate molded body 41B is preferably arranged in the second proximal sleeve forming portion 54 and the second proximal taper forming portion 55 with respect to the second axial direction of the second mold 51, and may also be arranged in the second straight tube forming portion 56. The distal sleeve portion 46 of the intermediate molded body 41B is preferably arranged in the second distal sleeve forming portion 58 and the second distal taper forming portion 57 with respect to the second axial direction of the second mold 51, and may also be arranged in the second straight tube forming portion 56. Furthermore, the outer diameter of the proximal sleeve portion 42 of the intermediate molded body 41B is preferably smaller than the inner diameter of the second proximal sleeve forming portion 54 and the second proximal taper forming portion 55 of the second mold 51, and the outer diameter of the distal sleeve portion 46 of the intermediate molded body 41B is preferably smaller than the inner diameter of the second distal sleeve forming portion 58 and the second distal taper forming portion 57 of the second mold 51.

[0108] Preferably, a portion of the proximal sleeve portion 42 and a portion of the distal sleeve portion 46 of the intermediate molded body 41B are positioned outside the lumen 52 of the second mold 51, and the proximal sleeve portion 42 and distal sleeve portion 46 are held by a fixing device outside the second mold 51. This allows the intermediate molded body 41B to be positioned approximately at the center of the lumen 52 of the second mold 51 in the vertical cross-section in the second axial direction of the second mold 51, making it easier to uniformly expand the intermediate molded body 41B in the radial direction during the second molding process.

[0109] The longitudinal length of the intermediate molded body 41B used in the second molding process, from the proximal sleeve portion 42 to the distal sleeve portion 46, is preferably 1.1 times or more, more preferably 1.2 times or more, and even more preferably 1.3 times or more, the length of the second axial direction of the lumen 52 of the second mold 51. This makes it easier to hold a portion of the proximal sleeve portion 42 and a portion of the distal sleeve portion 46 of the intermediate molded body 41B outside the lumen 52 of the second mold 51. There is no particular upper limit to the longitudinal length of the intermediate molded body 41B used in the second molding process, from the proximal sleeve portion 42 to the distal sleeve portion 46, but from the viewpoint of reducing the amount of resin used when manufacturing the balloon 10, it is preferably 10 times or less, more preferably 8 times or less, and even more preferably 5 times or less, the length of the second axial direction of the lumen 52 of the second mold 51.

[0110] In the second molding process, the intermediate molded body 41B is placed in the lumen 32 of the second mold 51, and then the intermediate molded body 41B is expanded to come into contact with the inner wall surface 53 of the second mold 51, while the projections 23 provided on the intermediate molded body 41B are inserted into the second recess 59 of the second mold 41. Specifically, by expanding the intermediate molded body 41B, a balloon molded body 61 is obtained having a straight pipe portion 64 in contact with the second straight pipe forming portion 56, a proximal tapered portion 63 in contact with the second proximal tapered portion 55, a proximal sleeve portion 62 in contact with the second proximal sleeve forming portion 54, a distal tapered portion 65 in contact with the second distal tapered portion 57, and a distal sleeve portion 66 in contact with the second distal sleeve forming portion 58. At this time, the protrusions 23 provided on the surface of the intermediate molded body 41B are inserted into the second recess 59 of the second mold 51, thereby obtaining a balloon molded body 61 formed in a balloon shape with protrusions 23 on its surface.

[0111] In the second molding step, it is preferable to heat the intermediate molded body 41B and introduce a fluid into the lumen of the intermediate molded body 41B to expand it. The intermediate molded body 41B can be heated by heating the second mold 51 with the intermediate molded body 41B placed in the lumen 52 of the second mold 51. For explanations regarding the heating of the intermediate molded body 41B and the fluid and pressurization introduced into it in the second molding step, refer to the explanations in the first molding step described above.

[0112] When the intermediate molded body 41B is expanded in the second molding process, it is preferable that the straight pipe portion 44 of the intermediate molded body 41B comes into contact with the second straight pipe forming portion 56 of the second mold 51, and it is also preferable that the proximal tapered portion 43 and distal tapered portion 45 of the intermediate molded body 41B come into contact with the second straight pipe forming portion 56.

[0113] The proximal tapered portion 43 of the intermediate molded body 41B may abut against the second proximal tapered portion 55 of the second mold 51, but it is preferable that it does not abut against the second proximal sleeve-forming portion 54. If the proximal tapered portion 43 abuts against the second proximal tapered portion 55, it is preferable that it abuts only the distal half of the second proximal tapered portion 55, more preferably only the distal one-third, and even more preferably only the distal one-quarter. It is particularly preferable that the proximal tapered portion 43 does not abut against the second proximal tapered portion 55, but abuts only against the second straight tube-forming portion 56. This makes it easier to form a smooth surface on the proximal tapered portion 63 of the balloon molded body 61.

[0114] The distal tapered portion 45 of the intermediate molded body 41B may abut against the second distal tapered forming portion 57 of the second mold 51, but it is preferable that it does not abut against the second distal sleeve forming portion 58. If the distal tapered portion 45 abuts against the second distal tapered forming portion 57, it is preferable that it abuts only the proximal 1 / 2 of the second distal tapered forming portion 57, more preferably only the proximal 1 / 3, and even more preferably only the proximal 1 / 4. It is particularly preferable that the distal tapered portion 45 does not abut against the second distal tapered forming portion 57, but abuts only against the second straight tube forming portion 56. This makes it easier to form a smooth surface on the distal tapered portion 65 of the balloon molded body 61.

[0115] When the intermediate molded body 41B is expanded in the second molding process, it is preferable that the proximal sleeve portion 42 of the intermediate molded body 41B abuts against the second proximal sleeve forming portion 54 of the second mold 51, and also abuts against the second proximal tapered portion 55. The proximal sleeve portion 42 of the intermediate molded body 41B may also abut against the second straight tube forming portion 56 of the second mold 51.

[0116] When the intermediate molded body 41B is expanded in the second molding process, it is preferable that the distal sleeve portion 46 of the intermediate molded body 41B abuts against the second distal sleeve forming portion 58 of the second mold 51, and also abuts against the second distal taper forming portion 57. The distal sleeve portion 46 of the intermediate molded body 41B may also abut against the second straight tube forming portion 56 of the second mold 51.

[0117] In the second molding step, the intermediate molded body 41B is expanded at least in the radial direction. The intermediate molded body 41B may also be expanded in the longitudinal direction, but in the second molding step, it is preferable to expand the resin tubular body 41B without stretching the intermediate molded body 41B in the longitudinal direction. This makes it easier for the protrusions 23 present on the proximal tapered portion 43, the straight pipe portion 44, and the distal tapered portion 45 of the intermediate molded body 41B to fit into the second recess 59 formed in the second straight pipe forming portion 56 of the second mold 51 when the intermediate molded body 41B is expanded in the second mold 51.

[0118] In the second molding process, the intermediate molded body 41B is expanded in the second mold 51 as described above to obtain a balloon molded body 61 having protrusions 23 on its surface. Preferably, the balloon molded body 61A has protrusions 23 on the surface of the straight tube portion 64, but does not have protrusions 23 on the proximal sleeve portion 42, the proximal tapered portion 43, the distal tapered portion 45, and the distal sleeve portion 46.

[0119] When the intermediate molded body 41B is inflated and the projection 23 is inserted into the second recess 59 of the second mold 51, it is preferable that the projection 23 does not come into contact with the bottom of the second recess 59, as shown in Figure 21. This makes it less likely that the projection 23 of the intermediate molded body 41A will be unintentionally distorted or crushed. Therefore, it becomes easier to form a balloon molded body 61 having a sharp projection 23 on its outer surface. In order to prevent the projection 23 from coming into contact with the bottom of the second recess 59 when the intermediate molded body 41B is inflated, it is preferable that the pressure inside the lumen of the intermediate molded body 41B when the intermediate molded body 41B is inflated in the second mold 51 during the second molding process be less than the pressure inside the lumen of the resin tubular body 21A when the resin tubular body 21A is inflated in the first mold 31 during the first molding process. Figure 21 shows an example in which a balloon molded body 61 is formed by blow molding using the second mold 51 shown in Figure 19.

[0120] It is preferable to include a step of removing the balloon molded body 61 from the second mold 51 after the second molding step (hereinafter referred to as the "second mold removal step"). In the second mold removal step, the second mold 51 may be removed from the balloon molded body 61 while the balloon molded body 61 is fixed, or the balloon molded body 61 may be removed from the second mold 51 while the second mold 51 is fixed. In the second mold removal step, it is preferable to lower the temperature of the second mold 51 to below the glass transition temperature of the resin constituting the intermediate molded body 41 before removing the balloon molded body 61 from the second mold 51.

[0121] In the second mold removal step, it is preferable to remove the balloon molded body 61 from the second mold 51 before the projection 23 reaches the bottom of the second recess 59 of the second mold 51. This makes it less likely that the projection 23 of the balloon molded body 61 will be unintentionally distorted or crushed. As a result, the resulting balloon 10 will have a sharp projection 16 on the outer surface of the straight tube portion, making it easier for the balloon 10 to bite into the calcified stenosis and cause a crack in the stenosis when it is expanded during angioplasty.

[0122] After the second mold removal step, it is preferable to include a cutting step in which the balloon molded body 61 is cut at the proximal sleeve portion 62 and the distal sleeve portion 66 (see Figures 5(D) to (E)). This makes it possible to obtain a balloon 10 having protrusions 16 on its surface. It is preferable to cut the balloon molded body 61 substantially perpendicular to the longitudinal direction of the balloon molded body 61. The balloon molded body 61 can be cut using known cutting means such as a cutter.

[0123] In the manufacturing method of the present invention, a balloon catheter 1 can be manufactured by attaching the balloon 10 obtained in the cutting step to the distal part of the shaft 2. Therefore, it is preferable that the manufacturing method of the present invention includes a step of attaching the balloon 10 obtained in the cutting step to the distal part of the shaft 2.

[0124] The manufacturing method of the present invention may further include one or more of the following steps: a protrusion surface polishing step, a protrusion surface roughening step, and a protrusion sharpening step. These steps may be performed at any time, but it is preferable to perform them after the second mold removal step.

[0125] In the protrusion surface polishing process, the surface of the protrusion 23 is polished using a polishing machine or the like. This makes the surface of the protrusion 16 of the resulting balloon 10 smooth, making it easier to make cuts in the calcified constricted area when the balloon 10 is expanded.

[0126] In the protrusion surface roughening process, the surface of the protrusion 23 is roughened with a file or the like. This increases the resistance friction of the surface of the protrusion 16 of the resulting balloon 10, making it easier for the protrusion 16 to bite into the calcified constricted area without slipping when the balloon 10 is expanded.

[0127] In the projection sharpening process, the tips of the projections 23 are sharpened by cutting with a cutter or laser. This makes it possible to form sharp tips on the projections 16 of the resulting balloon 10, making it easier to make cuts in the calcified constricted area when the balloon 10 is expanded.

[0128] The manufacturing method of the present invention may further include a protrusion division step. In the protrusion division step, the protrusion 23, which is provided as a convex ridge, is divided into multiple parts by making an incision. The depth of the incision does not need to be greater than the height of the protrusion 23. This makes it possible to form a balloon 10 in which multiple point-shaped protrusions 16 are arranged in a row. [Explanation of Symbols]

[0129] 1: Balloon catheter 2: Shaft 5: Hub 10: Balloon 11: Proximal sleeve portion (of the balloon) 12: Proximal tapered portion (of the balloon) 13: (The) straight tube section of the balloon 14: (The) distal tapered portion of the balloon 15: Distal sleeve portion (of the balloon) 16:Protrusion 21, 21A, 21P: Resin tubular body 22: Cylindrical section 23: Protrusion 24: Expanded diameter part 25: Section 1 26: Section 2 27: Third section 31: First mold 32: Lumen (of the first mold) 33: Inner wall surface (of the first mold) 34: First proximal sleeve forming section 35: First proximal tapered section 36: First straight pipe forming part 37: First distal taper forming section 38: First distal sleeve forming section 39: (The) recess (of the first mold), the first recess 41, 41A, 41B: Intermediate molded body 42: Proximal sleeve portion (of the intermediate molded body) 43: Proximal tapered portion (of the intermediate molded body) 44: Straight pipe section (of the intermediate molded body) 45: Distal tapered portion (of the intermediate molded body) 46: Distal sleeve portion (of the intermediate molded body) 51: Second mold 52: Lumen (of the second mold) 53: Inner wall surface (of the second mold) 54: Second proximal sleeve forming section 55: Second proximal tapered section 56:Second straight pipe forming part 57: Second distal taper forming section 58: Second distal sleeve forming section 59: (Second mold) recess, second recess 61: Balloon molded body 62: Proximal sleeve portion (of the balloon molded body) 63: Proximal tapered portion (of the balloon molded body) 64: (Straight tube section of a balloon-molded body) 65: Distal tapered portion (of the balloon molded body) 66: Distal sleeve portion (of the balloon molded body)

Claims

1. A step of preparing a resin tubular body having a longitudinal direction and a radial direction, and having protrusions on its surface, Steps to prepare a first mold having a lumen extending in a first axial direction from the proximal to the distal side, wherein the inner wall surface forming the lumen comprises a first straight pipe forming portion, a first proximal tapered forming portion located proximal to the first straight pipe forming portion and whose inner diameter decreases as it moves away from the first straight pipe forming portion, a first proximal sleeve forming portion located proximal to the first proximal tapered forming portion, a first distal tapered forming portion located distal to the first straight pipe forming portion and whose inner diameter decreases as it moves away from the first straight pipe forming portion, and a first distal sleeve forming portion located distal to the first distal tapered forming portion, wherein recesses are formed on the inner wall surfaces of the first straight pipe forming portion, the first proximal tapered forming portion, the first distal tapered forming portion, the first proximal sleeve forming portion, and the first distal sleeve forming portion, A first molding step to obtain an intermediate molded body having the projection on its surface, wherein the resin tubular body is placed in the lumen of the first mold, the resin tubular body is expanded to contact the inner wall surface of the first mold, and the projection is inserted into the recess, thereby obtaining an intermediate molded body having a straight pipe portion that contacts the first straight pipe forming portion, a proximal tapered portion that contacts the first proximal tapered portion, a proximal sleeve portion that contacts the first proximal sleeve forming portion, a distal tapered portion that contacts the first distal tapered portion, and a distal sleeve portion that contacts the first distal sleeve forming portion, A protrusion removal step of removing the protrusions present on the proximal sleeve portion and the distal sleeve portion of the intermediate molded body, Steps to prepare a second mold having a lumen extending in a second axial direction from the proximal to the distal side, wherein the inner wall surface forming the lumen comprises a second straight pipe forming portion, a second proximal taper forming portion located proximal to the second straight pipe forming portion and whose inner diameter decreases as it moves away from the second straight pipe forming portion, a second proximal sleeve forming portion located proximal to the second proximal taper forming portion, a second distal taper forming portion located distal to the second straight pipe forming portion and whose inner diameter decreases as it moves away from the second straight pipe forming portion, and a second distal sleeve forming portion located distal to the second distal taper forming portion, wherein the length of the second straight pipe forming portion in the second axial direction is formed to be longer than the length of the first straight pipe forming portion in the first axial direction, the inner diameter of the second straight pipe forming portion is formed to be larger than the inner diameter of the first straight pipe forming portion, and a recess is formed on the inner wall surface of the second straight pipe forming portion. A second molding step involves placing the intermediate molded body, from which a portion of the protrusions obtained in the protrusion removal step has been removed, into the cavity of the second mold, expanding the intermediate molded body to bring it into contact with the inner wall surface of the second mold, and causing the protrusions to enter the recesses. A method for manufacturing a balloon catheter having [a certain feature].

2. A method for manufacturing a balloon catheter according to claim 1, wherein in the first molding step, the resin tubular body is expanded while being pulled in the longitudinal direction.

3. A method for manufacturing a balloon catheter according to claim 1, wherein in the second molding step, the resin tubular body is expanded without stretching the intermediate molded body in the longitudinal direction.

4. A method for manufacturing a balloon catheter according to claim 1, wherein the length from the proximal end of the proximal tapered portion of the intermediate molded body to the distal end of the distal tapered portion is shorter than the length from the midpoint between the proximal and distal ends of the second proximal tapered portion of the second mold to the midpoint between the proximal and distal ends of the second distal tapered portion.

5. The method for manufacturing a balloon catheter according to claim 1, wherein the length from the proximal end of the proximal tapered portion of the intermediate molded body to the distal end of the distal tapered portion is shorter than the length in the second axial direction of the second straight tube forming portion of the second mold.

6. The method for manufacturing a balloon catheter according to claim 1, wherein the resin tubular body has an enlarged diameter portion in a part of its longitudinal direction, and in the first molding step, the portion of the resin tubular body including the enlarged diameter portion is placed in the lumen of the first mold.

7. The step of preparing the resin tubular body is: A step of preparing a straight tubular resin body having a first section, a second section, and a third section from one side in the longitudinal direction, and having protrusions on its surface, A process to heat the straight tubular resin body to stretch the first section and the third section in the longitudinal direction, thereby obtaining a resin tubular body having an enlarged diameter section in the second section. A method for manufacturing a balloon catheter according to claim 1, including the following:

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