Balloon for balloon catheter and method for manufacturing balloon catheter

Abstract

A method for manufacturing a balloon catheter comprises: a step of preparing a cylindrical parison (20) made of resin and a mold (30) having an inner cavity for inserting the parison (20) and forming a first groove (41) on the inner wall surface forming the inner cavity; a step of inserting the parison (20) into the inner cavity of the mold (30); a step of introducing a fluid into the inner cavity (23) of the parison (20) to expand the parison (20) and allow the resin to enter the first groove (41); and a step of removing the parison (20) from the mold (30) before the resin reaches the bottom (41a) of the first groove (41).

Description

Technical Field

[0001] The present invention relates to a balloon for a balloon catheter and a method for producing a balloon catheter using a cylindrical resin parison. Background Art

[0002] A balloon catheter is used to dilate a stenosis formed in a blood vessel, and a protrusion or a blade for biting into the stenosis is preferably provided on the surface of the balloon. For example, Patent Document 1 discloses a balloon having a protrusion, and a method for manufacturing a balloon having a step of forming a protrusion by mutually fusing at least parts of adjacent inner surfaces at a portion where the inner surfaces of the balloon are arranged opposite to each other. Patent Document 2 discloses a balloon having wrinkles formed as protrusions, and a method of forming wrinkles on a balloon using a mold.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2017-12678

[0004] Patent Document 2: Japanese Patent Application No. 2005-511187

[0005] However, although the protrusion of the balloon abuts against the stenosis, the protrusion does not bite sufficiently into the calcified lesion or plaque, and cracks are not easily formed, which leaves room for improvement. Summary of the invention

[0006] Therefore, the present invention aims to provide a balloon for a balloon catheter and a method for manufacturing a balloon catheter that can easily cut cracks in a calcified lesion or plaque at a stenotic part.

[0007] One embodiment of the balloon for a balloon catheter of the present invention that can solve the above-mentioned problems is characterized in that it has: a balloon body; and a protrusion, which is formed on the outer side of the balloon body and is made of the same material as the balloon body, and the surface roughness of the outer side of the protrusion is less than the surface roughness of the outer side of the balloon body. By setting the surface roughness of the outer side of the protrusion and the balloon body in this way, the friction resistance when the protrusion bites into the calcified lesions or plaques formed in the stenosis can be suppressed to be low. Therefore, it is easy to cut grooves on the calcified lesions or plaques in the stenosis, so that they are easy to form cracks, thereby preventing the dissociation of the vascular endothelium while expanding the stenosis. In addition, usually, the balloon catheter is delivered to the stenosis in a state where the balloon folded in a manner of covering the protrusion with the balloon membrane is stored in a protective tube. However, when delivering, the protrusion of the balloon abuts or scrapes against the outer surface of the balloon body, thereby there is a concern that the coating applied to the outer surface of the balloon body will peel off. However, according to the balloon of the present invention, the surface roughness of the protrusion is smaller than that of the balloon body, so that even if the protrusion abuts against the outer surface of the balloon body, the coating can be prevented from peeling off. Therefore, when the balloon is extended out of the protective tube and the catheter is used, the catheter can maintain a high passability in the body.

[0008] In the above-mentioned balloon for a balloon catheter, the protrusion preferably has a tip region including a radially outer end of the protrusion and a base region located radially inward of the tip region and having a larger surface roughness than the tip region.

[0009] The present invention also provides a method for manufacturing a balloon catheter. One embodiment of the method for manufacturing a balloon catheter of the present invention that can solve the above-mentioned problems is characterized in that it has: a step of preparing a cylindrical parison made of resin, and a mold having an inner cavity for inserting the parison and forming a first groove on the inner wall surface forming the inner cavity; a step of inserting the parison into the inner cavity of the mold; a step of introducing a fluid into the inner cavity of the parison to expand the parison and allow the resin to enter the first groove; and a step of removing the parison from the mold before the resin reaches the bottom of the first groove. The above-mentioned manufacturing method has a step of removing the parison from the mold before the resin reaches the bottom of the first groove, so that the concavo-convex shape of the inner wall surface of the first groove is not transferred at the top side of the protrusion. Therefore, the friction resistance when the protrusion bites into the calcified lesion or plaque formed in the stenosis can be suppressed to a low level. As a result, it is easy to cut a groove on the calcified lesion or plaque in the stenosis, so that cracks are easily formed. Therefore, the stenosis can be expanded while preventing the dissociation of the vascular endothelium.

[0010] In the above-mentioned manufacturing method, the protrusion formed on the outer surface of the blank after the process of allowing the resin to enter the first groove preferably has a base end area that blocks the entrance of the first groove by abutting against the inner wall surface of the first groove, and a top end area located radially outward of the base end area and separated from the inner wall surface of the first groove.

[0011] In the above manufacturing method, the surface roughness of the tip region of the protrusion is preferably smaller than the surface roughness of the outer side surface of the parison measured after the step of allowing the resin to enter the first groove.

[0012] The manufacturing method may further include a step of grinding the outer side surface of the protrusion. The manufacturing method may further include a step of sharpening the protrusion. The manufacturing method may further include a step of roughening the outer side surface of the protrusion.

[0013] In the above-mentioned manufacturing method, preferably, the protrusion extends in the longitudinal direction of the parison, and the manufacturing method further comprises a step of varying the height of the protrusion depending on the position in the longitudinal direction of the parison.

[0014] In the above-mentioned manufacturing method, it is preferred that the protrusion extends in the longitudinal direction of the parison, and the manufacturing method further comprises a step of cutting a groove on an outer side surface of the protrusion.

[0015] In the above manufacturing method, the first groove of the mold preferably has a contact area that contacts the base end area of ​​the parison and a non-contact area separated from the top end area of ​​the parison, and the contact area has an arc-shaped portion formed in a cross section of the mold perpendicular to the longitudinal direction.

[0016] In the above manufacturing method, preferably, the mold has a first section extending in the longitudinal direction thereof and forming a straight tube portion of the balloon, and the first groove is formed in the first section.

[0017] In the above-mentioned manufacturing method, it is preferred that the mold has a second section on both sides of the first section in its length direction and forming a tapered portion of the balloon, and a third section that exists at the end side of the above-mentioned mold in the length direction closer to the second section and forming a sleeve portion of the balloon. The second section is composed of a distal second section that exists at a position corresponding to the distal side of the balloon relative to the first section, and a proximal second section that exists at a position corresponding to the proximal side of the balloon relative to the first section. The third section is composed of a distal third section that exists at a position corresponding to the distal side of the balloon relative to the distal second section and forming a distal sleeve portion of the balloon, and a proximal third section that exists at a position corresponding to the proximal side of the balloon relative to the proximal second section and forming a proximal sleeve portion of the balloon. A third groove shallower than the first groove is formed on the inner wall surface of at least one of the distal third section and the proximal third section of the mold, and in the process of allowing the resin to enter the first groove, the resin reaches the bottom of the third groove.

[0018] In the manufacturing method, preferably, in the step of preparing the parison, a parison having a guide portion formed on an outer side surface protruding radially outward is prepared, and in the step of inserting the parison into the inner cavity of the mold, the guide portion is arranged in the third groove.

[0019] In the above-mentioned manufacturing method, it is preferred that the mold has a second section in its length direction that exists on both sides of the first section and forms a tapered portion of the balloon, and the second section is composed of a distal second section that exists at a position corresponding to the distal side of the balloon relative to the first section, and a proximal second section that exists at a position corresponding to the proximal side of the balloon relative to the first section, and no groove is formed on the inner wall surface of at least one of the distal second section and the proximal second section of the mold.

[0020] In the above manufacturing method, the first groove preferably has a portion whose width increases toward the outside in the radial direction.

[0021] In the above manufacturing method, the first groove preferably has a portion whose width decreases toward the outside in the radial direction.

[0022] According to the balloon for balloon catheter and the manufacturing method of the balloon catheter, the friction resistance when the protruding part of the balloon bites into the calcified lesion or plaque formed in the stenosis can be suppressed to a low level. Therefore, it is easy to cut a groove on the calcified lesion or plaque in the stenosis, so that cracks are easily formed, thereby preventing the dissociation of the vascular endothelium and expanding the stenosis. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A side view showing a balloon for a balloon catheter according to an embodiment of the present invention.

[0024] Figure 2 express Figure 1 II-II sectional view.

[0025] Figure 3 Indicates Figure 2 A cross-sectional view of a modified example of .

[0026] Figure 4 Indicates that Figure 2 An enlarged cross-sectional view of part P.

[0027] Figure 5 A perspective view showing a parison before expansion according to one embodiment of the present invention.

[0028] Figure 6 A cross-sectional view (partial side view) showing a state in which a parison before expansion is arranged in a mold according to one embodiment of the present invention is shown.

[0029] Figure 7 express Figure 6 The VII-VII cross-sectional view shows a cross section of the first section of the straight tube portion forming the balloon.

[0030] Figure 8 Indicates Figure 7 A cross-sectional view showing the parison in an expanded state is shown.

[0031] Fig. 9 Indicates that Figure 8 Enlarged cross-sectional view of part Q.

[0032] Fig.10 express Fig. 9 A cross-sectional view of a modified example of .

[0033] Fig.11 express Fig. 9 Cross-sectional views of other modified examples.

[0034] Fig.12 express Figure 6 The XII-XII cross-sectional view shows a cross section of the distal second section of the distal tapered portion forming the balloon.

[0035] Fig.13 express Figure 6 The XIII-XIII cross-sectional view shows a cross section of the second section on the proximal side of the proximal tapered portion forming the balloon.

[0036] Fig.14 express Figure 6 The XIV-XIV cross-sectional view shows a cross section of a distal third section of the distal sleeve portion forming the balloon.

[0037] Fig.15 express Figure 6 The XV-XV cross-sectional view shows a cross section of a third section of the proximal side of the proximal side sleeve portion forming the balloon.

[0038] Fig.16 express Figure 6 The XVI-XVI cross-sectional view shows a cross section of the fourth distal section outside the distal sleeve forming the balloon.

[0039] Fig.17 express Figure 6 The XVII-XVII cross-sectional view shows a cross section of the fourth section on the proximal side of the exterior of the proximal side sleeve forming the balloon. DETAILED DESCRIPTION

[0040] The present invention is described in more detail below based on the following embodiments, but the present invention is not limited to the following embodiments, and can be implemented with appropriate additional changes within the scope of the above and the following purports, and all of the above situations are included in the technical scope of the present invention. In addition, in each of the drawings, hatching, component reference numerals, etc. are sometimes omitted for ease of description, but in the above case, refer to the specification and other drawings. In addition, the sizes of various components in the drawings are preferentially conducive to the understanding of the features of the present invention, and therefore are sometimes different from the actual sizes.

[0041] 1. Balloon for balloon catheter

[0042] One embodiment of the balloon for a balloon catheter of the present invention is characterized in that it has: a balloon body; and a protrusion, which is formed on the outer side of the balloon body and is made of the same material as the balloon body, and the surface roughness of the outer side of the protrusion is less than the surface roughness of the outer side of the balloon body. By setting the surface roughness of the outer side of the protrusion and the balloon body in this way, the friction resistance when the protrusion bites into the calcified lesion or plaque formed in the stenosis can be suppressed to a lower level. Therefore, it is easy to cut a groove on the calcified lesion or plaque of the stenosis, so that cracks are easily formed, so that the stenosis can be expanded while preventing the dissociation of the vascular endothelium. In addition, usually, the balloon catheter is delivered to the stenosis in a state where the balloon folded in a manner of covering the protrusion with the balloon membrane is stored in a protective tube. However, when delivering, the protrusion of the balloon abuts or scrapes against the outer surface of the balloon body, thereby worrying that the coating applied to the outer surface of the balloon body will peel off. However, according to the balloon of the present invention, the surface roughness of the protrusion is smaller than that of the balloon body, so that even if the protrusion abuts against the outer surface of the balloon body, the coating can be prevented from peeling off. Therefore, when the balloon is extended out of the protective tube and the catheter is used, the catheter can maintain a high passability in the body. Hereinafter, the balloon for the balloon catheter is sometimes referred to as a "balloon".

[0043] Reference Figure 1-2 The balloon for the balloon catheter will be described. Figure 1 A side view showing a balloon for a balloon catheter according to an embodiment of the present invention, Figure 2 express Figure 1 II-II sectional view.

[0044] Balloon catheters are medical devices used in angioplasty (PTA, PTCA, etc.) to dilate narrowed blood vessels. It is well known that when blood vessels, which are the flow path for blood circulation in the body, become narrow, blood circulation stagnates, and various diseases occur. In particular, if coronary arteries that supply blood to the heart become narrow, there is a concern that major diseases such as angina pectoris and myocardial infarction may occur. Angioplasty is a minimally invasive treatment that does not require open-chest surgery such as bypass surgery, and is therefore widely practiced.

[0045] The balloon catheter has a shaft and a balloon arranged outside the shaft. The balloon catheter has a proximal side and a distal side, a balloon is arranged on the distal side of the shaft, and a hub is arranged on the proximal side of the shaft. In addition, the proximal side of the balloon refers to the direction close to the hand side of the user or the operator in the extension direction of the balloon catheter or the length axis of the shaft, and the distal side refers to the opposite direction of the proximal side, that is, the direction close to the treatment object side. In addition, the direction from the proximal side of the balloon toward the distal side is called the proximal-distal direction.

[0046] like Figure 1-2As shown, the balloon 1 has a balloon body 6 and a protrusion 10, which is formed on the outer side 7 of the balloon body 6 and is made of the same material as the balloon body 6. The balloon body 6 defines the basic shape of the balloon 1, and is preferably formed into a bag-like shape with openings on the proximal side and the distal side. The protrusion 10 is preferably provided on the outer side 7 of the balloon body 6 in a dot-shaped, line-shaped or mesh-shaped pattern. By providing the protrusion 10 on the outer side 7 of the balloon body 6 and giving the protrusion 10 a scoring function, it is possible to cut cracks in the calcified stenosis during angioplasty and expand it. In addition, it is also possible to achieve high strength of the balloon 1 and suppress excessive expansion during pressurization.

[0047] In the present invention, the protrusion 10 of the balloon 1 refers to a portion formed to have a relatively high film thickness in the radial direction compared to a predetermined position of the balloon body 6. In the case where one protrusion 10 is provided for the balloon body 6, as shown in FIG. Figure 2 As shown, the above-mentioned predetermined position refers to the position A opposite to the radial outer end 11 of the protrusion 10 in the circumferential direction of the balloon 1. In the case where a plurality of protrusions 10 are provided on the balloon body 6, as shown in FIG. Figure 3 As shown, the predetermined position refers to a position B corresponding to the midpoint of the outer ends 11 of the protrusions 10 adjacent in the circumferential direction of the balloon 1 .

[0048] The maximum height of the protrusion 10 in the radial direction is preferably 1.2 times or more, more preferably 1.5 times or more, and further preferably 2 times or more of the membrane thickness at the above-mentioned specified position of the balloon body 6. It is also allowed to be less than 100 times, less than 50 times, less than 30 times, or less than 10 times. Thus, it is easy to cut a groove of appropriate depth on the calcified lesion or plaque of the stenosis, so that cracks are easily formed.

[0049] When the protrusion 10 is formed in a dot or line shape, the protrusion 10 is preferably configured to extend in the proximal and distal directions of the balloon 1. In addition, the protrusion 10 may also be configured to extend in a spiral shape around the center of the long axis of the balloon 1. Furthermore, the protrusion 10 may also be configured to extend in the circumferential direction of the balloon 1. Thus, the contact area between the protrusion 10 and the stenosis can be adjusted, so that the passing performance of the catheter in the body cavity and the anti-slip performance of the balloon 1 relative to the stenosis can be taken into account.

[0050] like Figure 1As shown, the balloon 1 comprises: a straight tube portion 2; tapered portions 3 located on both sides of the straight tube portion 2 and having an outer diameter that decreases toward the end side in the distal direction x1; a sleeve portion 4 located on the end side in the distal direction x1 relative to the tapered portion 3 and connected to the shaft of the balloon catheter; and a sleeve outer portion 5 located on the end side in the distal direction x1 relative to the sleeve portion 4 and cut off before the balloon 1 is attached to the shaft. The tapered portion 3 located on the distal side relative to the straight tube portion 2 is referred to as a distal tapered portion 3D, and the tapered portion 3 located on the proximal side relative to the straight tube portion 2 is referred to as a proximal tapered portion 3P. In addition, the sleeve portion 4 located on the distal side relative to the distal tapered portion 3D is referred to as a distal sleeve portion 4D, and the sleeve portion 4 located on the proximal side relative to the proximal tapered portion 3P is referred to as a proximal sleeve portion 4P. The sleeve outer portion 5 located on the distal side of the distal sleeve portion 4D is referred to as a distal sleeve outer portion 5D, and the sleeve outer portion 5 located on the proximal side of the proximal sleeve portion 4P is referred to as a proximal sleeve outer portion 5P.

[0051] The protrusion 10 is preferably disposed on the straight tube portion 2. Thus, the protrusion 10 can easily bite into the stenosis when the balloon 1 is expanded. The protrusion 10 can also be disposed on the straight tube portion 2 and the tapered portion 3 to easily cut cracks in the stenosis.

[0052] Figure 3 Indicates Figure 2 A cross-sectional view of a modified example of Figure 2 As shown, only one protrusion 10 may be provided. Figure 3 As shown, a plurality of protrusions 10 may also be provided. In this case, it is preferred that a plurality of protrusions 10 are arranged in a circumferential direction, and it is more preferred that the protrusions 10 are arranged at equal intervals in the circumferential direction. By providing a plurality of protrusions 10 in this way, cracks can be easily cut out at multiple locations of the narrow part. In addition, it is preferred that a plurality of protrusions 10 are separated in the circumferential direction, and it is more preferred that the separation distance between adjacent protrusions 10 in the circumferential direction is greater than the maximum circumference of the protrusion 10.

[0053] The balloon body 6 and the protrusion 10 are made of the same material, thereby maintaining the softness of the balloon 1 while preventing the protrusion 10 from damaging the outer side 7 of the balloon body 6. The balloon body 6 and the protrusion 10 are preferably integrally molded. Thus, the protrusion 10 can be prevented from falling off the balloon body 6. Such a balloon 1 can be manufactured, for example, by placing a parison extruded by extrusion molding in a mold having a groove and by biaxial stretch blow molding. The preferred method for manufacturing the balloon will be described later in the section "2. Method for manufacturing a balloon catheter".

[0054] As the resin constituting the balloon body 6 and the protrusion 10, for example, polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymers, polyester resins such as polyethylene terephthalate and polyester elastomers, polyurethane resins such as polyurethane and polyurethane elastomers, polyphenylene sulfide resins, polyamide resins such as polyamide and polyamide elastomers, fluorine resins, silicone resins, natural rubbers such as latex rubber, etc. are cited. Only one of these resins can be used, or two or more can be used at the same time. Among them, polyamide resins, polyester resins, and polyurethane resins are preferably used. In particular, elastomer resins are preferably used from the perspective of the filmization and flexibility of the balloon 1. For example, among the polyamide resins, nylon 12 and nylon 11 are cited as the preferred materials for the balloon 1. From the perspective of being able to be relatively easily molded during blow molding, nylon 12 is preferably used. In addition, from the perspective of the filmization and flexibility of the balloon 1, polyamide elastomers such as polyetheresteramide elastomers and polyamideether elastomers are preferably used. Among them, polyetheresteramide elastomer is preferably used because it has high yield strength and good dimensional stability of the balloon 1 .

[0055] The surface roughness of the outer side surface 12 of the protrusion 10 is less than the surface roughness of the outer side surface 7 of the balloon body 6. By reducing the surface roughness of the protrusion 10 in this way, it is easy to cut a groove on the calcified lesion or plaque of the stenosis, so that cracks are easily formed, thereby preventing the dissociation of the vascular endothelium while expanding the stenosis. The surface roughness of the outer side surface 12 of the protrusion 10 is preferably 0.01 times or more of the surface roughness of the outer side surface 7 of the balloon body 6, more preferably 0.05 times or more, and further preferably 0.1 times or more. In addition, it is also allowed to be less than 0.9 times, less than 0.8 times, and less than 0.7 times. As a method for reducing the surface roughness of the outer side surface 12 of the protrusion 10, a method of grinding the protrusion 10 using a grinder or a file is cited.

[0056] In the case where the balloon body 6 is provided with only one protrusion 10, as Figure 2 As shown, the surface roughness of the outer side surface 7 of the balloon body 6 is obtained by measuring the portion of the outer side surface 7 of the balloon body 6 including the above-mentioned position A. In the case where the balloon body 6 is provided with a plurality of protrusions 10, as shown in FIG. Figure 3 As shown in FIG. 1 , the surface roughness of the outer side surface 7 of the balloon body 6 is obtained by measuring the portion of the outer side surface 7 of the balloon body 6 including the above-mentioned position B. Figure 2-3 As shown, the surface roughness of the outer side surface 12 of the protrusion 10 is obtained by measuring the portion of the outer side surface 12 of the protrusion 10 including the radial outer end 11 of the protrusion 10 (i.e., the top end of the protrusion 10). In addition, in the case of multiple protrusions 10, any protrusion 10 can be measured.

[0057] The surface roughness is the arithmetic mean roughness (arithmetic mean deviation) Ra of the outer side surface of the balloon body 6 or the protrusion 10 in the reference length interval of the roughness curve, and the reference length is 0.1 mm. The above-mentioned arithmetic mean roughness Ra is equivalent to the arithmetic mean roughness Ra specified in JIS B 0601 (2001) and is measured according to JIS B 0633 (2001). The measurement is performed using a measuring machine specified in JIS B0651 (2001) (for example, a laser microscope VK-9510 manufactured by Keyence Corporation).

[0058] The surface roughness of the entire outer side surface 12 of the protrusion 10 (i.e., the entire outer circumference of the protrusion 10) is preferably smaller than the surface roughness of the outer side surface 7 of the balloon body 6. This makes it easier to cut grooves in calcified lesions or plaques at the stenosis, further promoting the formation of cracks.

[0059] like Figure 3 As shown, when the balloon body 6 is provided with a plurality of protrusions 10, the surface roughness of the outer side 12 of all protrusions 10 is preferably smaller than the surface roughness of the outer side 7 of the balloon body 6. Thus, it is easy to cut grooves on the calcified lesions or plaques at the stenosis, further promoting the formation of cracks.

[0060] Figure 4 Indicates that Figure 2 FIG. 1 is an enlarged cross-sectional view of a portion P of the balloon 1 having the protrusion 10. Figure 4 As shown, the protrusion 10 preferably has: a top region 13, which includes the radially outer end 11 of the protrusion 10; and a base region 14, which is located radially inward of the top region 13 and has a greater surface roughness than the top region 13. As a result, the top region 13 can easily cut grooves on the calcified lesions or plaques of the stenosis, thereby easily forming cracks, thereby preventing the dissociation of the vascular endothelium while expanding the stenosis. In addition, since the friction resistance between the base region 14 and the stenosis can be increased, the anti-slip performance of the balloon 1 relative to the stenosis can be improved.

[0061] The surface roughness of the base end region 14 is preferably at least twice, more preferably at least three times, and even more preferably at least five times that of the surface roughness of the tip end region 13 , but may be 20 times or less, 18 times or less, or 15 times or less.

[0062] The surface roughness of the base end region 14 can be the same as the surface roughness of the outer side surface 7 of the balloon body 6, or preferably be more than 0.1 times the surface roughness of the outer side surface 7 of the balloon body 6, more preferably be more than 0.2 times, and further preferably be more than 0.3 times. In addition, it is also allowed to be less than 0.9 times, less than 0.8 times, and less than 0.7 times.

[0063] The orientation of the molecules may be different in the tip region 13 and the base region 14. For example, the molecules may be oriented parallel to the radially outer side or the direction of movement of the resin during blow molding in the tip region 13, and the molecules may be oriented perpendicular to the radially outer side or the direction of movement of the resin during blow molding in the base region 14. For example, the orientation of the molecules can be measured using X-ray diffraction or Raman spectroscopy.

[0064] The crystallinity may be different between the tip region 13 and the base region 14. The crystallinity of the tip region 13 is preferably higher than that of the base region 14. Thus, cooling strain is less likely to occur in the tip region 13 when the protrusion 10 is manufactured, and thus excessive deformation of the tip region 13 can be prevented. The crystallinity can be calculated, for example, based on a calorific value obtained from a DSC curve obtained by differential scanning calorimetry.

[0065] 2. Balloon catheter manufacturing method

[0066] One embodiment of the method for manufacturing a balloon catheter of the present invention is characterized in that it has the steps of preparing a cylindrical parison made of resin and a mold having an inner cavity for inserting the parison and forming a first groove on the inner wall surface forming the inner cavity; inserting the parison into the inner cavity of the mold; introducing a fluid into the inner cavity of the parison to expand the parison and allow the resin to enter the first groove; and removing the parison from the mold before the resin reaches the bottom of the first groove. The above-mentioned manufacturing method has the step of removing the parison from the mold before the resin reaches the bottom of the first groove, so the concavo-convex shape of the inner wall surface of the first groove is not transferred at the top end side of the protrusion. Therefore, the friction resistance when the protrusion bites into the calcified lesion or plaque formed in the stenosis can be suppressed to a low level. As a result, it is easy to cut a groove on the calcified lesion or plaque in the stenosis, so that cracks are easily formed. Therefore, the stenosis can be expanded while preventing the dissociation of the vascular endothelium. In addition, the balloon described in "1. Balloon for balloon catheter" can be manufactured by the above-mentioned manufacturing method.

[0067] Reference Figures 5 to 9 The above-mentioned production method will be described. Figure 5 A perspective view showing a parison before expansion according to one embodiment of the present invention, Figure 6 A cross-sectional view (partial side view) showing a state where a parison before expansion is arranged in a mold according to one embodiment of the present invention is shown. Figure 7 express Figure 6 The VII-VII cross-sectional view shows a cross section of the first section of the straight tube portion forming the balloon. Figure 8 Indicates Figure 7 A cross-sectional view of the parison in an expanded state is shown. Fig. 9 Indicates that Figure 8 Enlarged cross-sectional view of part Q.

[0068] First, a parison 20 and a mold 30 are prepared. The parison 20 is a cylindrical member made of resin. The parison 20 is manufactured by extrusion molding, for example. The parison 20 has a first end 21 and a second end 22, and extends in a length direction x2 from the first end 21 toward the second end 22.

[0069] like Figure 5 As shown, the cross-sectional shape of the parison 20 in the direction perpendicular to the length direction x2 can also be roughly uniform in the length direction x2. As a result, the productivity of the parison 20 can be improved. In addition, the cross-sectional shape of the parison 20 in the direction perpendicular to the length direction x2 can also be different depending on the position in the length direction x2. The outer diameter of a part of the parison 20 in the length direction x2 (for example, the part corresponding to the straight tube part and the tapered part of the balloon) can also be larger than other parts outside the part. In order to make the cross-sectional shape of the parison 20 different in the length direction x2, other molds can also be used in advance for blow molding.

[0070] As a material constituting the parison 20 , the description of the resin constituting the balloon body 6 and the protrusion 10 thereof described in “1. Balloon for balloon catheter” can be referred to.

[0071] The mold 30 has an inner cavity 35 for inserting the parison 20. Specifically, it is preferred that a portion of the parison 20 in the length direction x2 is arranged in the mold 30. Figure 6 As shown, the mold 30 has a length direction x3 corresponding to the length direction x2 of the parison 20. In order to easily arrange the parison 20 in the mold 30, the length direction x3 of the mold 30 is preferably consistent with the length direction x2 of the parison 20.

[0072] like Figure 6As shown, the mold 30 preferably has a first section 31 forming a straight tube portion of the balloon in the length direction x3 thereof, and a second section 32 existing on both sides of the first section 31 and forming a tapered portion of the balloon. In addition, the mold 30 may also have a third section 33 existing at the end side of the length direction x3 of the second section 32 and forming a sleeve portion of the balloon, and a fourth section 34 existing at the end side of the length direction x3 of the third section 33 and forming the sleeve outside of the balloon. The second section 32 is preferably composed of a distal second section 32D existing at a position corresponding to the distal side of the balloon than the first section 31, and a proximal second section 32P existing at a position corresponding to the proximal side of the balloon than the first section 31. The third section 33 is preferably composed of a distal third section 33D that exists at a position corresponding to the distal side of the balloon compared to the distal second section 32D and forms the distal sleeve portion of the balloon, and a proximal third section 33P that exists at a position corresponding to the proximal side of the balloon compared to the proximal second section 32P and forms the proximal sleeve portion of the balloon. The fourth section 34 is preferably composed of a distal fourth section 34D that exists at a position corresponding to the distal side of the balloon compared to the distal third section 33D and forms the outside of the distal sleeve of the balloon, and a proximal fourth section 34P that exists at a position corresponding to the proximal side of the balloon compared to the proximal third section 33P and forms the outside of the proximal sleeve of the balloon.

[0073] The mold 30 may be formed of only one part or multiple parts. For example, the mold 30 may be formed of multiple half-divided bodies, or may be formed by connecting multiple mold parts to each other in the near and far directions. The mold 30 is preferably formed of multiple mold parts whose inner cavity cross-sectional shapes are changed in stages. Figure 6 In the embodiment, the mold 30 includes a first mold 30A, a second mold 30B, a third mold 30C, a fourth mold 30D, a fifth mold 30E, and a sixth mold 30F in order from the proximal side. Figure 6 As shown, the adjacent mold parts may be connected by engaging each other. Although not shown, magnets may be attached to the adjacent mold parts, and the parts may be connected by attracting each other.

[0074] The cross-sectional shape of the inner cavity of the mold 30 can be formed into a circular shape, an oblong shape, a polygonal shape, or a shape obtained by combining these shapes. In addition, the oblong shape includes an elliptical shape, an egg shape, and a rounded rectangle.

[0075] like Figure 7 As shown, a first groove 41 is formed on the inner wall surface 36 of the mold 30 that forms the inner cavity 35. Figure 6-7 As shown, the parison 20 is inserted into the inner cavity 35 of the mold 30. Fluid is introduced into the inner cavity 23 of the parison 20 to expand the parison 20, as shown in FIG. Figure 8 As shown, the resin is allowed to enter the first groove 41. In this way, by expanding the parison 20, the resin constituting the parison 20 enters the first groove 41, so that the protrusion 25 can be formed on the outer side surface of the parison 20.

[0076] In the present invention, the protrusion 25 of the parison 20 refers to a portion formed to be higher in the radial direction than the film thickness at a predetermined position of the expanded parison 20. The predetermined position can be referred to by replacing the term "balloon body" in the description of the predetermined position of the balloon body 6 described in "1. Balloon for balloon catheter" with another term "parison".

[0077] Before the resin reaches the bottom 41a of the first groove 41, the parison 20 is removed from the mold 30. Thus, the concavo-convex shape of the inner wall surface of the first groove 41 is not transferred at the top side of the protrusion 25, so the friction resistance when the protrusion 25 bites into the calcified lesion or plaque formed in the stenosis can be suppressed to be low. Therefore, it is easy to cut a groove on the calcified lesion or plaque in the stenosis, so that cracks are easily formed. As a result, the stenosis can be expanded while preventing the dissociation of the vascular endothelium. The expanded parison 20 can be used as a balloon for a balloon catheter. By installing the expanded parison 20 on the distal side of the shaft, a balloon catheter can be manufactured.

[0078] like Figure 7 As shown, one or more first grooves 41 can be provided. It is also possible to arrange a plurality of first grooves 41 in a circumferential direction. In this case, the first grooves 41 are preferably arranged at equal intervals in the circumferential direction. By arranging the first grooves 41 in this way, it is also possible to arrange a plurality of protrusions that enter the first grooves 41, so that cracks can be easily cut out at multiple locations of the narrow part. In addition, it is preferred that the first grooves 41 are separated in the circumferential direction, and it is more preferred that the separation distance of the adjacent first grooves 41 in the circumferential direction is greater than the maximum circumference of the first groove 41.

[0079] The first groove 41 preferably extends along the longitudinal direction x3 of the mold 30 . Thus, the protrusion 25 can be extended along the longitudinal direction x3 of the mold 30 .

[0080] The depth of the first groove 41 may be the same in the longitudinal direction x3 of the mold 30 , or may be different depending on the position in the longitudinal direction x3 .

[0081] like Fig. 9As shown in FIG. 1 , the protrusion 25 formed on the outer side surface of the parison 20 after the step of allowing the resin to enter the first groove 41 preferably includes a base end region 29 that blocks the entrance of the first groove 41 by abutting against the inner wall surface of the first groove 41, and a tip region 28 that is located radially outward of the base end region 29 and separated from the inner wall surface of the first groove 41. The tip region 28 preferably includes a radially outer end 26 of the protrusion 25. Since the base end region 29 is a portion abutting against the inner wall surface of the first groove 41, the concavo-convex shape of the inner wall surface of the first groove 41 is transferred. In contrast, since the tip region 28 is a portion separated from the inner wall surface of the first groove 41 of the mold 30, the concavo-convex shape of the inner wall surface of the first groove 41 is not transferred. By adjusting the amount of resin entering the first groove 41 in this way, the concavo-convex shapes of the outer surfaces of the tip region 28 and the base end region 29 of the protrusion 25 can be made different. Furthermore, after the parison 20 is removed from the mold 30 , the boundary between the tip end region 28 and the base end region 29 of the protrusion 25 can be confirmed by observing the cross section of the parison 20 perpendicular to the proximal direction using a microscope.

[0082] like Fig. 9 As shown in FIG. 1 , the first groove 41 preferably has a portion 41b whose width decreases toward the radially outer side. This makes it easier to sharpen the protrusion 25, and the protrusion 25 can easily cut a groove in the calcified lesion or plaque in the narrow part, so that cracks are easily formed. Fig. 9 As shown in FIG. 1 , the first groove 41 may have a depth that decreases toward the radially outer side as a whole. Fig.10 As shown, the portion 41 b whose width decreases toward the outside in the radial direction may be arranged on the inlet side of the first groove 41 .

[0083] Fig.10 express Fig. 9 A cross-sectional view of a modified example of Fig.10 As shown in FIG. 1 , the first groove 41 preferably has a portion 41c whose width increases toward the radially outer side. In this case, the portion 41c whose width increases toward the radially outer side is preferably arranged on the side close to the bottom 41a of the first groove 41. Thus, the resin is unlikely to reach the bottom 41a of the first groove 41, and deformation of the protrusion 25 can be prevented.

[0084] like Fig.10As shown, the first groove 41 may also have both a portion 41b whose width decreases toward the radial outside and a portion 41c whose width increases toward the radial outside. In this case, it is preferred that the portion 41c whose width increases toward the radial outside is located radially outward (i.e., the bottom 41a side of the first groove 41) than the portion 41b whose width decreases toward the radial outside. As a result, the resin does not easily reach the bottom 41a of the first groove 41, and the concavo-convex shape of the inner wall surface of the first groove 41 can be transferred to the parison 20 at the entrance side of the first groove 41. Therefore, it is easy to form the parison 20 having the top end region 28 and the base end region 29.

[0085] The surface roughness of the tip region 28 of the protrusion 25 is preferably smaller than the surface roughness of the outer surface of the parison 20 measured after the step of allowing the resin to enter the first groove 41. By reducing the surface roughness of the tip region 28 of the protrusion 25 in this way, it is easy to cut a groove on the calcified lesion or plaque of the stenosis, thereby making it easy to form a crack. Therefore, the stenosis can be expanded while preventing the dissociation of the vascular endothelium.

[0086] The measurement location of the surface roughness of the outer surface of the parison 20 can be referred to by replacing the term “parison” with “balloon body” in the description of the measurement location of the surface roughness of the outer surface 7 of the balloon body 6 described in “1. Balloon for Balloon Catheter”.

[0087] The surface roughness is the arithmetic mean roughness Ra of the inner wall surface of the mold 30 or the outer side surface of the parison 20 in the reference length interval of the roughness curve, and the reference length is 0.1 mm. The above-mentioned arithmetic mean roughness Ra is equivalent to the arithmetic mean roughness Ra specified in JIS B 0601 (2001) and is measured according to JIS B 0633 (2001). The measurement is performed using a measuring machine specified in JIS B 0651 (2001) (for example, a laser microscope VK-9510 manufactured by Keyence Corporation).

[0088] Methods for increasing the surface roughness of the inner wall surface of the mold 30 and the outer surface of the parison 20 include roughening these surfaces mechanically or chemically, such as etching, sandblasting, and using a wire brush or sandpaper.

[0089] The surface roughness of the base end region 29 is preferably at least twice, more preferably at least three times, and even more preferably at least five times that of the surface roughness of the tip end region 28 , but may be 20 times or less, 18 times or less, or 15 times or less.

[0090] The surface roughness of the base end region 29 can be the same as the surface roughness of the outer side surface of the preform 20 measured after the process of allowing the resin to enter the first groove 41, or preferably be 0.1 times or more, more preferably 0.2 times or more, and further preferably 0.3 times or more of the surface roughness of the outer side surface of the preform 20. In addition, it is also allowed to be less than 0.9 times, less than 0.8 times, and less than 0.7 times.

[0091] The manufacturing method preferably further comprises a step of grinding the outer side surface 27 of the protrusion 25. Thus, the concavo-convex shape of the outer side surface 27 of the protrusion 25 can be changed. In addition, by grinding the outer side surface 27 of the protrusion 25, the tip of the protrusion 25 can be sharpened, and the surface roughness of the tip region 28 of the protrusion 25 can be made smaller than the surface roughness of the outer side surface of the parison 20 measured after the step of allowing the resin to enter the first groove 41. A grinder or a file can be used for grinding.

[0092] The manufacturing method may also include a step of sharpening the projection 25. In this case, the top region 28 of the projection 25 is preferably sharpened. Thus, the projection 25 can easily cut a groove on the calcified lesion or plaque of the stenotic portion, thereby easily forming a crack. Therefore, the stenotic portion can be expanded while preventing the dissociation of the vascular endothelium. As a method for sharpening the projection 25, in addition to the method of grinding the outer side surface 27 of the projection 25, a method of cutting the outer side surface 27 of the projection 25 using a laser processing device or a tool can also be cited.

[0093] The manufacturing method may further include a step of roughening the outer side surface 27 of the protrusion 25. This can improve the friction resistance when the narrow portion contacts the protrusion 25, thereby improving the anti-slip performance of the balloon. In order to achieve both improved anti-slip performance and prevent the coating applied to the outer surface of the balloon from peeling off, only a portion of the circumferential direction of the protrusion 25 of the parison 20 may be roughened.

[0094] In the above manufacturing method, it is preferred that the protrusion 25 extends along the length direction x2 of the parison 20, and a step is included in which the height of the protrusion 25 is varied according to the position in the length direction x2 of the parison 20. In addition, here, the height of the protrusion 25 means the height in the radial direction from the inner surface of the balloon body. By making the height of the protrusion 25 different, the protrusion 25 can easily bite into the narrow part, thereby improving the anti-slip performance of the balloon.

[0095] The protrusion 25 extends along the length direction x2 of the parison 20, and the manufacturing method preferably further comprises a step of cutting a groove on the outer side surface 27 of the protrusion 25. By cutting the groove on the protrusion 25, the passing performance of the catheter in the body cavity can be improved. The groove can be formed using a tool such as a cutter or a knife.

[0096] The protrusion 25 may be divided into a plurality of parts by cutting out grooves. One or more grooves may be provided for one protrusion 25. The depth of the grooves may be smaller than the height of the protrusion 25. Thus, when the balloon formed by the expanded parison 20 is inserted into the body, body fluids and the like can be prevented from entering the balloon from the grooved portion. The width of the grooves is not particularly limited, but is preferably smaller than the width of the protrusion 25.

[0097] The groove may also be formed along the extension direction of the protrusion 25. The groove preferably extends along the length direction x2 of the parison 20. In addition, the groove may also extend in a spiral shape around the center of the long axis of the parison 20. By extending the groove in this way, the passing performance of the catheter in the body cavity can be improved.

[0098] The cut groove may extend along the circumferential direction of the parison 20. By extending the cut groove in this way, the anti-slip performance of the balloon with respect to the stenosis portion can be improved.

[0099] Fig.11 express Fig. 9 Cross-sectional views of other modified examples. Fig.11 As shown, the first groove 41 of the mold 30 preferably has an abutting area 42 abutting against the base end area 29 of the parison 20 and a non-abutting area 43 separated from the top end area 28 of the parison 20, and the abutting area 42 has an arc-shaped portion 41d formed in an arc shape on a cross section perpendicular to the longitudinal direction x3 of the mold 30. As a result, the rapid shape change from the outer side surface of the parison 20 to the base end area 29 of the protrusion 25 can be alleviated, so that the protrusion 25 can be prevented from being broken by external force.

[0100] The arc-shaped portion 41d is preferably formed in a portion including the radially inner end of the contact region 42. This can improve the effect of easing the change in the outer shape from the outer side surface of the parison 20 to the protrusion 25. A linear portion may be formed in the first groove 41 of the mold 30 radially outward of the arc-shaped portion 41d.

[0101] like Figure 6 to Figure 8 As shown, the mold 30 preferably has a first section 31 extending in the length direction x3 and forming the straight tube portion of the balloon, and a first groove 41 is formed in the first section 31. Thus, the protrusion 25 can be formed on the parison 20 at a position corresponding to the straight tube portion of the balloon.

[0102] Preferably, the mold 30 has second sections 32 that exist on both sides of the first section 31 in the length direction x3 and form the tapered portion of the balloon, and the second section 32 is composed of a distal second section 32D that exists at a position corresponding to the distal side of the balloon relative to the first section 31, and a proximal second section 32P that exists at a position corresponding to the proximal side of the balloon relative to the first section 31, and a second groove 45 is formed in at least one of the distal second section 32D and the proximal second section 32P of the mold 30. Thus, the second protrusion is formed at a position corresponding to the tapered portion of the balloon, so that the anti-slip performance of the balloon relative to the stenosis can be improved.

[0103] Preferably, the mold 30 has a second section 32 that exists on both sides of the first section 31 in the length direction x3 and forms the tapered portion of the balloon, and the second section 32 is composed of a distal second section 32D that exists at a position corresponding to the distal side of the balloon relative to the first section 31, and a proximal second section 32P that exists at a position corresponding to the proximal side of the balloon relative to the first section 31, and a groove is not formed on the inner wall surface of at least one of the distal second section 32D and the proximal second section 32P of the mold 30. As a result, no protrusion is formed at a position corresponding to the tapered portion of the balloon in the parison 20, so that the sliding performance of the tapered portion of the balloon can be appropriately ensured, thereby further improving the passing performance of the balloon.

[0104] Preferably, the mold 30 has a second section 32 existing on both sides of the first section 31 and forming a tapered portion of the balloon, and a third section 33 existing at the end side of the length direction x3 closer to the second section 32 and forming a sleeve portion of the balloon, the second section 32 is composed of a distal second section 32D existing at a position corresponding to the distal side of the balloon relative to the first section 31, and a proximal second section 32P existing at a position corresponding to the proximal side of the balloon relative to the first section 31, and the third section 33 is composed of a distal second section 32D existing at a position corresponding to the distal side of the balloon relative to the first section 31. The second section 32D is located at a position corresponding to the distal side of the balloon and forms the distal sleeve portion of the balloon, and the proximal third section 33P is located at a position corresponding to the proximal side of the balloon and forms the proximal sleeve portion of the balloon. A third groove 47 shallower than the first groove 41 is formed on the inner wall surface of at least one of the distal third section 33D and the proximal third section 33P of the mold 30, and in the process of allowing the resin to enter the first groove 41, the resin reaches the bottom of the third groove 47. Thus, the third protrusion lower than the protrusion 25 (first protrusion) can be formed at a position corresponding to the sleeve portion of the balloon in the parison 20, thereby improving the passing performance of the sleeve portion of the balloon in the body.

[0105] Preferably, in the process of preparing the parison 20, the parison 20 having a guide portion protruding radially outward formed on the outer side surface is prepared, and in the process of inserting the parison 20 into the inner cavity 35 of the mold 30, the guide portion is arranged in the third groove 47. Thus, after the parison 20 is expanded by introducing a fluid into the inner cavity 35 of the parison 20, the guide portion abuts against the third groove 47, thereby preventing the parison from rotating. Therefore, the protrusion formed on the outer side surface of the balloon or the balloon body can be manufactured into a desired shape.

[0106] Fig.12 express Figure 6 The XII-XII cross-sectional view shows a cross section of the distal second section 32D forming the distal tapered portion of the balloon. Fig.13 express Figure 6 The XIII-XIII cross-sectional view of FIG. 1 shows a cross section of the proximal second section 32P of the proximal tapered portion of the balloon. Fig.12 In the following figures, the parison 20 in the mold 30 is omitted. Figure 6 , Figure 12-13 As shown, the second section 32 is preferably composed of a distal second section 32D and a proximal second section 32P, and the second groove 45 is formed on the inner wall surface 36 of the proximal second section 32P, and no groove is formed on the inner wall surface 36 of the distal second section 32D. Thus, the sliding performance of the distal tapered portion of the balloon is appropriately ensured, so that the passing performance of the balloon can be improved, and the second protrusion is formed on the proximal tapered portion, so that the anti-slip performance of the balloon relative to the stenosis can be improved.

[0107] Fig.14 express Figure 6 The XIV-XIV cross-sectional view shows a cross section of the distal third section 33D of the distal sleeve portion forming the balloon. Fig.15 express Figure 6 The XV-XV cross-sectional view shows a cross section of the proximal third section 33P of the proximal sleeve portion forming the balloon. Figure 6 , Figure 14-15 As shown, the third section 33 of the mold 30 is preferably composed of a distal third section 33D and a proximal third section 33P, and a third groove 47 is formed on the inner wall surface 36 of at least one of the distal third section 33D and the proximal third section 33P. In this case, in the process of allowing the resin to enter the first groove 41, the resin preferably reaches the bottom of the third groove 47. Thus, a protrusion can also be provided at a position corresponding to the sleeve portion of the balloon in the parison 20.

[0108] Fig.16 express Figure 6 The XVI-XVI cross-sectional view shows a cross section of the distal fourth section 34D outside the distal sleeve forming the balloon. Fig.17 express Figure 6 The XVII-XVII cross-sectional view shows a cross section of the proximal fourth section 34P outside the proximal sleeve forming the balloon. Figure 6 , Figure 16-17 As shown, the mold 30 may include a distal fourth section 34D and a proximal fourth section 34P, and a fourth groove 49 may be formed on the inner wall surface 36 of at least one of the distal fourth section 34D and the proximal fourth section 34P. In this case, in the step of allowing the resin to enter the first groove 41, it is preferred that the resin reaches the bottom of the fourth groove 49. Thus, a protrusion can also be provided at a position in the parison 20 corresponding to the outer portion of the sleeve of the balloon.

[0109] The depths of the third groove 47 and the fourth groove 49 are preferably smaller than the first groove 41. Thus, in the process of allowing the resin to enter the first groove 41, it is easy for the resin to reach the bottom of the third groove 47 or the fourth groove 49 earlier than the resin completely enters the first groove 41, so that the effect of fixing the position corresponding to the sleeve portion of the balloon or the sleeve outside in the parison 20 by the mold 30 can be improved. Therefore, when the fluid is introduced into the inner cavity 23 of the parison 20 to expand the parison 20, the rotation of the parison 20 can be prevented, and the protrusion 25 can be prevented from being crushed.

[0110] The second grooves 45 to 49 may have the same or different shapes in the inner cavity cross section of the mold 30. The shapes of the second grooves 45 to 49 can refer to the description of the first groove 41.

[0111] This application claims the benefit of priority based on Japanese Patent Application No. 2019-108432 filed on June 11, 2019. The entire contents of the specification of Japanese Patent Application No. 2019-108432 filed on June 11, 2019 are incorporated herein by reference.

[0112] Description of reference numerals:

[0113] 1...balloon; 2...straight tube; 3...conical portion; 4...sleeve portion; 5...exterior of sleeve; 6...balloon body; 7...exterior side of balloon body; 10...protrusion; 11...exterior end; 12...exterior side of protrusion; 13...top region; 14...base region; A, B, C...position; 20...parison; 21...first end; 22...second end; 23...inner cavity; 25...protrusion; 26...exterior end; 27...exterior side of protrusion; 28...top region; 29...base region; 30...mold; 30A...first mold; 30B...second mold; 30C...third mold; 30D...fourth mold; 30E...fifth mold; 30F...sixth mold; 31...first interval; 32...the second section; 32D...the second section on the distal side; 32P...the second section on the proximal side; 33...the third section; 33D...the third section on the distal side; 33P...the third section on the proximal side; 34...the fourth section; 34D...the fourth section on the distal side; 34P...the fourth section on the proximal side; 35...the inner cavity; 36...the inner wall surface forming the inner cavity; 41...the first groove; 41a...the bottom; 41b...the portion whose width decreases toward the radial outside; 41c...the portion whose width increases toward the radial outside; 41d...the arc-shaped portion; 42...the abutment area; 43...the non-abutment area; 45...the second groove; 47...the third groove; 49...the fourth groove; x1...the distal direction; x2...the length direction of the parison; x3...the length direction of the mold.

Claims

1. A balloon for a balloon catheter, characterized in that: have: a balloon body; and a protrusion formed on the outer side of the balloon body and made of the same material as the balloon body, The balloon body and the protrusion are integrally formed in a manner to prevent the protrusion from falling off the balloon body. The protrusion has a tip region including a radially outer end of the protrusion and a base region located radially inward of the tip region and having a surface roughness greater than that of the tip region.

2. The balloon for a balloon catheter according to claim 1, wherein: The surface roughness of the outer side surface of the top region is smaller than the surface roughness of the outer side surface of the balloon body.

3. A balloon for a balloon catheter, characterized in that: have: a balloon body; and a protrusion formed on the outer side of the balloon body and made of the same material as the balloon body, The surface roughness of the outer side surface of the protrusion is smaller than the surface roughness of the outer side surface of the balloon body. The surface roughness of the outer surface of the balloon body is measured in a cross section across the length direction at a portion including a position opposite to the radial outer end of the protrusion in the circumferential direction of the balloon or at a portion including a midpoint in the circumferential direction of the outer end of the protrusion adjacent in the circumferential direction.

4. A method for manufacturing a balloon catheter, the balloon catheter comprising the balloon according to any one of claims 1 to 3, characterized in that: have: A step of preparing a cylindrical parison made of resin and a mold having an inner cavity into which the parison is inserted and having a first groove formed on an inner wall surface forming the inner cavity; The step of inserting the parison into the inner cavity of the mold; A step of introducing a fluid into the inner cavity of the parison to expand the parison so that a portion of the cylindrical parison made of resin enters the first groove; as well as A step of removing the parison from the mold before a portion of the cylindrical parison made of resin reaches the bottom of the first groove.

5. The manufacturing method according to claim 4, wherein: The protrusion formed on the outer surface of the preform after the process of allowing a part of the tubular preform made of resin to enter the first groove has a base end area that blocks the entrance of the first groove by abutting against the inner wall surface of the first groove, and a top end area located radially outward of the base end area and separated from the inner wall surface of the first groove.

6. The manufacturing method according to claim 5, wherein: The surface roughness of the tip region of the protrusion is smaller than the surface roughness of the outer side surface of the parison measured after the step of causing a part of the cylindrical parison made of resin to enter the first groove.

7. The manufacturing method according to claim 5 or 6, wherein: The method for manufacturing the balloon catheter further includes a step of grinding the outer side surface of the protrusion.

8. The manufacturing method according to claim 5 or 6, wherein: The method for manufacturing the balloon catheter further includes a step of sharpening the protrusion.

9. The manufacturing method according to claim 5 or 6, wherein: The method for manufacturing the balloon catheter further includes a step of roughening the outer side surface of the protrusion.

10. The manufacturing method according to claim 5 or 6, wherein: The protrusion extends along the length direction of the parison, The method for manufacturing the balloon catheter further includes a step of varying the height of the protrusion according to the position of the parison in the longitudinal direction.

11. The manufacturing method according to claim 5 or 6, wherein: The protrusion extends along the length direction of the parison, The method for manufacturing the balloon catheter further includes a step of cutting a groove on the outer side surface of the protrusion.

12. The manufacturing method according to claim 5 or 6, wherein: The first groove of the mold has a contact area that contacts the base end area of ​​the parison and a non-contact area that is separated from the top end area of ​​the parison. The contact region includes an arc-shaped portion formed in an arc shape in a cross section perpendicular to the longitudinal direction of the mold.

13. The manufacturing method according to claim 4 or 5, wherein: The mold has a first section extending along its length direction and forming a straight tube portion of the balloon. The first groove is formed in the first section.

14. The manufacturing method according to claim 13, wherein: The mold has a second section on both sides of the first section in its length direction and forming a tapered portion of the balloon, and a third section that is located closer to the end side of the mold in the length direction than the second section and forming a sleeve portion of the balloon. The second section is composed of a distal second section located at a position corresponding to the distal side of the balloon relative to the first section, and a proximal second section located at a position corresponding to the proximal side of the balloon relative to the first section. The third section is composed of a distal third section that exists at a position corresponding to the distal side of the balloon relative to the distal second section and forms a distal sleeve portion of the balloon, and a proximal third section that exists at a position corresponding to the proximal side of the balloon relative to the proximal second section and forms a proximal sleeve portion of the balloon. A third groove shallower than the first groove is formed on the inner wall surface of at least one of the distal third section and the proximal third section of the mold, In the step of causing a portion of the cylindrical parison made of resin to enter the first groove, the portion of the cylindrical parison made of resin reaches the bottom of the third groove.

15. The manufacturing method according to claim 14, wherein: In the step of preparing the parison, a parison having a guide portion protruding radially outwardly formed on an outer side surface is prepared. In the step of inserting the parison into the inner cavity of the mold, the guide portion is arranged in the third groove.

16. The manufacturing method according to claim 13, wherein: The mold has a second section on both sides of the first section in the length direction thereof and forms a tapered portion of the balloon. The second section is composed of a distal second section located at a position corresponding to the distal side of the balloon relative to the first section, and a proximal second section located at a position corresponding to the proximal side of the balloon relative to the first section. A groove is not formed on an inner wall surface of at least one of the distal second section and the proximal second section of the mold.

17. The manufacturing method according to claim 4 or 5, wherein: The first groove has a portion whose width increases toward the outer side in the radial direction.

18. The manufacturing method according to claim 4 or 5, wherein: The first groove has a portion whose width decreases toward the outer side in the radial direction.

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