Guide wire

Abstract

This guide wire comprises: a core shaft; a first coating film that covers the outer periphery of the core shaft, the surface roughness of the first coating film being greater than the surface roughness of the core shaft; and a resin coating film that covers the outer periphery of the first coating film.

Description

Guidewire

[0001] The technology disclosed herein relates to guidewires.

[0002] A known guidewire has a laminated structure of an oxide coating layer and a resin coating layer formed on the outer periphery of a core shaft (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2016-221141

[0004] The resin coating that covers the outer periphery of the guidewire is required to be durable enough to prevent peeling off during the procedure due to contact with the blood vessel wall, etc. In order to improve the durability of the resin coating, conventional guidewires have had room for improvement in the adhesion between the resin coating and the components located inside the resin coating.

[0005] This specification discloses a technique that can solve the above-mentioned problems.

[0006] The technology disclosed in this specification has been made to solve at least part of the above-mentioned problems, and can be realized in the following forms.

[0007] (1) The guide wire disclosed in this specification includes a core shaft, a first coating covering the outer periphery of the core shaft, the first coating having a surface roughness greater than that of the core shaft, and a resin coating covering the outer periphery of the first coating.

[0008] This guidewire has a first coating covering the outer periphery of the core shaft, and the surface roughness of the first coating is greater than the surface roughness of the core shaft, thereby improving adhesion between the core shaft located inside the resin coating and the resin coating.

[0009] (2) In the above guidewire, the first coating may have a recess recessed toward the inside in the radial direction of the core shaft.

[0010] According to this guidewire, a portion of the resin coating enters the recess, and the first coating and the resin coating locally engage with each other, thereby further improving the adhesion between the core shaft and the resin coating.

[0011] (3) In the above guidewire, the recess may be linear and extend along the circumferential direction of the core shaft.

[0012] According to this guide wire, the engaging portion between the recess and the resin coating is linear and extends along the circumferential direction of the core shaft, thereby further improving the adhesion between the core shaft and the resin coating.

[0013] (4) In the above guidewire, the recess may be linear and extend along the longitudinal direction of the core shaft.

[0014] According to this guide wire, the engaging portion between the recess and the resin coating is linear and extends along the longitudinal direction of the core shaft, thereby further improving the adhesion between the core shaft and the resin coating.

[0015] (5) In the above guidewire, the recess may be a line extending spirally along the longitudinal direction of the core shaft.

[0016] According to this guide wire, the engaging portion between the recess and the resin coating is linear and extends spirally along the longitudinal direction of the core shaft, thereby further improving the adhesion between the core shaft and the resin coating.

[0017] (6) In the above guide wire, the first coating may further include a convex portion adjacent to the concave portion when viewed radially of the core shaft and positioned radially outward of the core shaft relative to the concave portion, and the first coating may have an uneven interface between the concave portion and the convex portion when viewed radially of the core shaft.

[0018] With this guide wire, part of the resin coating penetrates into the irregularities at the interface between the recessed and protruding portions, and the first coating and the resin coating are locally engaged, thereby further improving the adhesion between the core shaft and the resin coating.

[0019] (7) In the above guide wire, the first coating may be an oxide coating formed by oxidizing the surface of the core shaft.

[0020] According to this guidewire, the first coating can be formed relatively easily.

[0021] (8) The above guide wire may further include a coil including a wire wound spirally around the outer periphery of the core shaft, and a second coating covering the outer periphery of the wire, wherein the resin coating covers the outer periphery of the second coating, and the surface roughness of the second coating may be greater than the surface roughness of the wire.

[0022] This guide wire has a second coating covering the outer periphery of the wire, and the surface roughness of the second coating is greater than the surface roughness of the wire, thereby improving adhesion between the wire positioned inside the resin coating and the resin coating.

[0023] (9) In the above guide wire, the second coating may be an oxide coating formed by oxidizing the surface of the wire.

[0024] According to this guidewire, the second coating can be formed relatively easily.

[0025] The technology disclosed in this specification can be realized in various forms, for example, in the form of a guidewire manufacturing method, a catheter, a catheter manufacturing method, an endoscope, a dilator, etc.

[0026] FIG. 1 is an explanatory diagram illustrating a guidewire of a first embodiment. FIG. 2 is an explanatory diagram illustrating a longitudinal cross section of the guidewire of the first embodiment. FIG. 3 is an explanatory diagram illustrating a portion of the appearance of a first coating. FIG. 4 is an explanatory diagram illustrating a portion of the longitudinal cross section of a core shaft. FIG. 5 is an electron microscope (SEM) photograph of the first coating. FIG. 6 is an electron microscope (SEM) photograph of the first coating. FIG. 7 is an explanatory diagram illustrating a portion of the appearance of a guidewire of a second embodiment. FIG. 8 is an explanatory diagram illustrating a cross section of the guidewire of the second embodiment. FIG. 9 is an explanatory diagram illustrating a portion of the appearance of a guidewire of a third embodiment. FIG. 10 is an explanatory diagram illustrating a portion of the longitudinal cross section of the guidewire of the third embodiment. FIG. 11 is an explanatory diagram illustrating a guidewire of a fourth embodiment. FIG. 12 is an explanatory diagram illustrating a longitudinal cross section of the guidewire of the fourth embodiment. FIG. 13 is an explanatory diagram illustrating a portion of the appearance of the first coating. FIG. 14 is an explanatory diagram illustrating a portion of the longitudinal cross section of a core shaft. FIG. 15 is an electron microscope (SEM) photograph of the first coating. FIG. 16 is an electron microscope (SEM) photograph of the first coating. FIG. 17 is an explanatory diagram illustrating a portion of the longitudinal cross section of a guidewire of a fifth embodiment.

[0027] <First Embodiment> Fig. 1 is an explanatory diagram illustrating a guidewire 1 according to a first embodiment. The guidewire 1 will be described with reference to Figs. 1 to 6. The sizes of the components of the guidewire 1 shown in Figs. 1 to 4 are merely examples and may be expressed on a scale different from the actual size.

[0028] The guidewire 1 is a medical device that is inserted into blood vessels or digestive organs and is primarily used to insert other medical devices, such as catheters, into the body. The guidewire 1 has a core shaft 10 (FIG. 2), a first coating 20, a resin coating 50, and a coil 60. In this embodiment, the resin coating 50 is permeable, so the components inside the resin coating 50 are also shown in FIGS. 1 and 3. The first coating 20 has protrusions 30 and recesses 40, as described below.

[0029] FIG. 2 is an explanatory diagram illustrating a longitudinal cross section of the guidewire 1. The core shaft 10 is a long member extending along the longitudinal direction of the guidewire 1. The outer diameter of the core shaft 10 gradually decreases toward the distal end. The core shaft 10 has, in order from the distal end to the proximal end of the core shaft 10, a first straight portion 11, a tapered portion 12, and a second straight portion 13. The first straight portion 11 includes the distal end of the core shaft 10. The second straight portion 13 includes the proximal end of the core shaft 10. The outer diameter of the first straight portion 11 is approximately constant in the longitudinal direction of the core shaft 10. The outer diameter of the first straight portion 11 is the smallest in the core shaft 10. The outer diameter of the second straight portion 13 is approximately constant in the longitudinal direction of the core shaft 10. The outer diameter of the second straight portion 13 is the largest in the core shaft 10. The tapered portion 12 is provided between the first straight portion 11 and the second straight portion 13. The outer diameter of the tapered portion 12 gradually decreases toward the tip side. Although not shown, in this embodiment, the first straight portion 11, the tapered portion 12, and the second straight portion 13 each have a circular cross section.

[0030] There are no particular limitations on the material of the core shaft 10. Examples of materials that can be used for the core shaft 10 include stainless steel (SUS302, SUS304, SUS316, etc.), superelastic alloys such as Ni-Ti alloys, piano wire, nickel-chromium alloys, cobalt alloys, platinum, gold, and tungsten.

[0031] The first coating 20 is a thin film that covers a part of the tapered portion 12 of the core shaft 10 and the outer periphery of the second straight portion 13. The first coating 20 will be described in detail later.

[0032] The coil 60 is formed by a wire 61 wound helically around the outer periphery of the core shaft 10 along the longitudinal direction of the core shaft 10. The tip of the coil 60 and the tip of the core shaft 10 are joined by a joint 70. The rear end of the coil 60 and the tapered portion 12 of the core shaft 10 are joined by a joint 71.

[0033] There are no particular limitations on the material of the coil 60. Examples of materials that can be used for the coil 60 include stainless steel (SUS302, SUS304, SUS316, etc.), superelastic alloys such as Ni-Ti alloys, piano wire, nickel-chromium alloys, cobalt alloys, platinum, gold, and tungsten.

[0034] There are no particular limitations on the material of the joints (70, 71). Examples of the material that can be used for the joints (70, 71) include brazing material (aluminum alloy brazing, silver brazing, gold brazing, etc.), metal solder (Ag—Sn alloy, Au—Sn alloy, etc.), and adhesive (epoxy adhesive, etc.).

[0035] The resin coating 50 is a thin film made of resin and covers the outer periphery of each of the first coating 20, the coil 60, the joints 70, and the joints 71.

[0036] The resin coating 50 can be formed from a hydrophobic resin material, a hydrophilic resin material, or a mixture thereof. Examples of hydrophobic resin materials that can be used include silicone resin, polyurethane, polyethylene, polyvinyl chloride, polyester, polypropylene, polyamide, polystyrene, polyolefin elastomer, polyester elastomer, polyamide elastomer, and polyurethane elastomer. Examples of hydrophilic resin materials that can be used include starches such as carboxymethyl starch, celluloses such as carboxymethyl cellulose, polysaccharides such as alginic acid, chitin, chitosan, and hyaluronic acid, and natural water-soluble polymers such as gelatin, and synthetic water-soluble polymers such as polyvinyl alcohol, polyethylene oxide, polyethylene glycol, polypropylene glycol, polyvinylpyrrolidone, and water-soluble nylon.

[0037] <Details of First Coating 20> Figure 3 is an explanatory diagram illustrating a portion of the appearance of the first coating 20. The first coating 20 is a thin film that covers a portion of the outer periphery of the core shaft 10 (Figure 2). The first coating 20 is a film-like oxide formed by bonding of the metal material contained in the core shaft 10 with oxygen. That is, the first coating 20 in this embodiment is an oxide coating formed by oxidizing the surface of the core shaft 10. The first coating 20 has protrusions 30 and recesses 40.

[0038] The protrusions 30 are part of the first coating 20. The protrusions 30 are adjacent to the recesses 40 when viewed in the radial direction of the core shaft 10. The protrusions 30 are located radially outward of the recesses 40. The protrusions 30 have fine irregularities on their outer surfaces. The surface roughness of the protrusions 30 (hereinafter referred to as "surface roughness S1") is greater than the surface roughness of the core shaft 10 (hereinafter referred to as "surface roughness S2"). In other words, the relationship between the surface roughness S1 and the surface roughness S2 is expressed by an inequality S1 > S2. For example, the surface roughness S1 of the protrusions 30 in this embodiment, expressed in terms of the root mean square height (Sq), is 0.01 μm to 10 μm. On the other hand, the surface roughness S2 of the core shaft 10 in this embodiment, expressed in terms of the root mean square height (Sq), is 0.001 μm to 5 μm. The surface roughness S2 of the core shaft 10 in this embodiment refers to the surface roughness of the portion of the core shaft 10 that is not covered with the first coating 20. In this embodiment, it refers to the surface roughness of the first straight portion 11 and the surface roughness of the tip side of the tapered portion 12 that is not covered with the first coating 20.

[0039] In this embodiment, the distance between adjacent convex portions 30 in the longitudinal direction of the core shaft 10 is referred to as the "distance L1," and the length of the convex portion 30 itself in the longitudinal direction of the core shaft 10 is referred to as the "width W1." In this embodiment, the distances L1 between adjacent convex portions 30 are substantially the same. In this embodiment, the widths W1 of the convex portions 30 are substantially the same.

[0040] The recesses 40 are portions of the first coating 20 that are recessed radially inward of the core shaft 10 relative to the protrusions 30. The recesses 40 are linear and extend along the circumferential direction of the core shaft 10. A plurality of recesses 40 are formed along the longitudinal direction of the core shaft 10. In this embodiment, the distance between adjacent recesses 40 in the longitudinal direction of the core shaft 10 is referred to as the "distance L2," and the length of the recess 40 itself in the longitudinal direction of the core shaft 10 is referred to as the "width W2" of the recess 40. In this embodiment, the distances L2 between adjacent recesses 40 are approximately the same. The widths W2 of the recesses 40 in this embodiment are approximately the same.

[0041] FIG. 4 is an explanatory diagram illustrating a portion of the longitudinal cross section of the core shaft 10. In this embodiment, the film thickness of the protrusion 30 is referred to as "film thickness T1," and the film thickness of the recess 40 is referred to as "film thickness T2." As described above, because the recess 40 is recessed radially inward of the core shaft 10, the film thickness T2 of the recess 40 is smaller than the film thickness T1 of the protrusion 30. In this embodiment, the film thickness T1 of the protrusion 30 is approximately 0.1 μm to approximately 10 μm. The film thickness of a dense coating formed on the surface of a specific metal material, generally referred to as a "passive coating," is on the order of a few nanometers. Therefore, the so-called passive coating and the first coating 20 of this embodiment have different film thicknesses. The film thickness of the first coating 20 is larger than that of a typical passive coating. In each figure, the thickness of the first coating 20 is exaggerated for illustrative purposes. However, since the thickness of the first coating 20 is relatively smaller than the outer diameter of the core shaft 10 (approximately 0.2 mm to approximately 1.0 mm), the influence of the first coating 20 on the outer diameter of the guide wire 1 is small.

[0042] A method for manufacturing the first coating 20 will be exemplified. First, a metal wire is ground to produce a core shaft 10 having a first straight portion 11, a tapered portion 12, and a second straight portion 13. The core shaft 10 is rotated about its longitudinal axis, and a laser is irradiated onto the outer circumferential surface of the core shaft 10. The first coating 20 is formed on the portion directly irradiated with the laser (hereinafter referred to as the "irradiated portion"). Accordingly, heat from the laser is transferred to the periphery of the irradiated portion (hereinafter referred to as the "peripheral portion"). This promotes an oxidation reaction in the peripheral portion, and the first coating 20 is also formed in the peripheral portion. In the irradiated portion, the laser locally evaporates the core shaft 10. As a result, a recessed shape is formed radially inward of the core shaft 10, forming a recess 40. As the first coating 20 is formed in the peripheral portion, a fine uneven shape is generated, forming a protrusion 30. By adjusting conditions such as the laser output and irradiation time, it is possible to adjust the film thicknesses (T1, T2) of the convex portions 30 and the concave portions 40, the surface roughness S1 of the convex portions 30, and the like.

[0043] The first coating 20 can also be formed by a known chemical surface treatment such as a passivation treatment in which a coating is formed by immersing the core shaft 10 in a treatment liquid containing an oxidizing agent. The above-described method of manufacturing the first coating 20 by laser heating makes it easier to form the first coating 20 than a manufacturing method using a treatment liquid, and since the first coating 20 can be formed without using an oxidizing agent, workers can work more safely.

[0044] FIGS. 5 and 6 are scanning electron microscope (SEM) photographs of the first coating 20 of the first embodiment. FIG. 5 is an SEM photograph of the first coating 20 of the first embodiment, observed at 100x magnification. FIG. 6 is an SEM photograph of the first coating 20 of the first embodiment, observed at 1000x magnification. FIGS. 5 and 6 show a portion of the first coating 20 formed by laser heating on the outer periphery of the core shaft 10 ( FIG. 2 ) made of a stainless steel alloy. As described above, multiple convex portions 30 and multiple concave portions 40 are alternately formed along the longitudinal direction of the core shaft 10. In FIGS. 5 and 6 , the fine irregularities of the convex portions 30 are depicted as being closer to black as the concave portions become deeper, and closer to white as the convex portions become taller. As shown in FIG. 6 , a portion of the concave portions 40 has melted and solidified into a spherical shape due to heat.

[0045] The first coating 20 has unevenness at the interface between the recessed portion 40 and the protruding portion 30 when viewed in the radial direction of the core shaft 10. More specifically, with reference to Fig. 6, the boundary line between the recessed portion 40 and the protruding portion 30 has a wavy shape when viewed in the radial direction of the core shaft 10. In other words, at the interface between the protruding portion 30 and the recessed portion 40, a portion that protrudes toward the recessed portion 40 and a portion that is recessed toward the opposite side from the recessed portion 40 are repeated in the circumferential direction of the core shaft 10.

[0046] In this embodiment, the first coating 20 is formed on part of the tapered portion 12 of the core shaft 10 and on the outer periphery of the second straight portion 13. However, the area where the first coating 20 is formed on the core shaft 10 can be set as desired. For example, the first coating 20 may be formed on the outer periphery of the first straight portion 11, and may not be formed on the outer periphery of the second straight portion 13. The first coating 20 may be formed on the outer periphery of a member other than the core shaft 10, such as the coil 60, the joint portion 70, and the joint portion 71. In such a case, adhesion between the member on whose outer periphery the first coating 20 is formed and the resin coating 50 covering the outer periphery thereof is improved.

[0047] The guidewire 1 of the present embodiment described above includes a core shaft 10, a first coating 20 covering the outer periphery of the core shaft 10, the first coating 20 having a surface roughness greater than that of the core shaft 10, and a resin coating 50 covering the outer periphery of the first coating 20. The contact area between the first coating 20 and the resin coating 50 is larger than the contact area between the outer periphery of the core shaft 10 and the resin coating 50 when the resin coating 50 is formed directly on the outer periphery of the core shaft 10 that does not have the first coating 20. This improves adhesion between the core shaft 10 and the resin coating 50 of the guidewire 1. In other words, the core shaft 10 and the resin coating 50 of the guidewire 1 are more firmly bonded to each other, and peeling of the resin coating 50 from the core shaft 10 can be suppressed.

[0048] The first coating 20 has a recess 40. A portion of the resin coating 50 enters the recess 40, and the first coating 20 and the resin coating 50 locally engage with each other, thereby further improving the adhesion between the core shaft 10 and the resin coating 50.

[0049] The recess 40 is linear and extends along the circumferential direction of the core shaft 10. As a result, an engagement portion between the recess 40 and the resin coating 50 is formed along the circumferential direction of the core shaft 10, and the adhesion between the core shaft 10 and the resin coating 50 is further improved.

[0050] The first coating 20 further includes a protrusion 30 that is adjacent to the recess 40 when viewed in the radial direction of the core shaft 10 and is located radially outward of the recess 40 on the core shaft 10. The first coating 20 has irregularities at the interface between the recess 40 and the protrusion 30 when viewed in the radial direction of the core shaft 10. As a result, a portion of the resin coating 50 penetrates into the irregularities at the interface between the recess 40 and the protrusion 30, and the first coating 20 and the resin coating 50 locally engage with each other, thereby further improving the adhesion between the core shaft 10 and the resin coating 50.

[0051] The first coating 20 is an oxide coating formed by oxidizing the surface of the core shaft 10. This makes it possible to form the first coating 20 relatively easily.

[0052] 7 is an explanatory diagram illustrating a portion of the external appearance of a guidewire 1a according to a second embodiment. The guidewire 1a according to the second embodiment differs from the guidewire 1 according to the first embodiment in the form of the first coating. A description of the common parts of the guidewire 1a and the guidewire 1 will be omitted.

[0053] The first coating 20a of the second embodiment has a protrusion 30a and a recess 40a. The recess 40a of the second embodiment is linear and extends along the longitudinal direction of the core shaft 10. A plurality of recesses 40a are formed along the circumferential direction of the core shaft 10.

[0054] In this embodiment, the distance between adjacent protrusions 30a in the circumferential direction of the core shaft 10 is referred to as the "distance L1a," and the length of the protrusion 30a itself in the circumferential direction of the core shaft 10 is referred to as the "width W1a." In this embodiment, the distances L1a between adjacent protrusions 30a are substantially the same. In this embodiment, the widths W1a of the protrusions 30a are substantially the same.

[0055] In this embodiment, the distance between adjacent recesses 40a in the circumferential direction of the core shaft 10 is referred to as the "distance L2a," and the length of the recess 40a itself in the circumferential direction of the core shaft 10 is referred to as the "width W2a" of the recess 40a. In this embodiment, the distances L2a between adjacent recesses 40a are approximately the same. The widths W2a of the recesses 40a in this embodiment are approximately the same.

[0056] 8 is an explanatory diagram illustrating a cross section of the guide wire 1a of the second embodiment. In this embodiment, multiple recesses 40a are formed at equal intervals in the circumferential direction of the core shaft 10. In this embodiment, the film thickness of the protrusions 30a is referred to as the "film thickness T1a," and the film thickness of the recesses 40a is referred to as the "film thickness T2a." Because the recesses 40a are recessed radially inward of the core shaft 10, the film thickness T2a of the recesses 40a is smaller than the film thickness T1a of the protrusions 30a.

[0057] In the guide wire 1a of the present embodiment described above, the recess 40a is linear and extends along the longitudinal direction of the core shaft 10. As a result, the engagement portion between the recess 40a and the resin coating 50 is formed along the longitudinal direction of the core shaft 10, and the adhesion between the core shaft 10 and the resin coating 50 is further improved.

[0058] 9 is an explanatory diagram illustrating a portion of the external appearance of a guidewire 1b according to a third embodiment. The guidewire 1b according to the third embodiment differs from the guidewire 1 according to the first embodiment in the form of the first coating. A description of the commonalities between the guidewire 1b and the guidewire 1 will be omitted.

[0059] The first coating 20b of the third embodiment has a protrusion 30b and a recess 40b. The recess 40b of the third embodiment is linear and extends spirally along the longitudinal direction of the core shaft 10. In this embodiment, the recess 40b is formed continuously from the rear end to the front end of the recess 40b.

[0060] In this embodiment, the distance between adjacent portions of the protrusion 30b in the longitudinal direction of the core shaft 10 is referred to as the "distance L1b," and the length of the protrusion 30b itself in the longitudinal direction of the core shaft 10 is referred to as the "width W1b." In this embodiment, the distances L1b between adjacent portions are substantially the same. In this embodiment, the widths W1b of the protrusions 30b are substantially the same.

[0061] In this embodiment, the distance between adjacent portions of the recess 40b in the longitudinal direction of the core shaft 10 is referred to as the "distance L2b," and the length of the recess 40b itself in the longitudinal direction of the core shaft 10 is referred to as the "width W2b" of the recess 40b. In this embodiment, the distances L2b between adjacent portions are substantially the same. In this embodiment, the widths W2b of the recesses 40b are substantially the same.

[0062] 10 is an explanatory diagram illustrating a portion of a longitudinal cross section of a guidewire 1b according to a third embodiment. In this embodiment, the thickness of the protruding portion 30b is referred to as a "thickness T1b," and the thickness of the recessed portion 40b is referred to as a "thickness T2b." Because the recessed portion 40b is recessed radially inward of the core shaft 10, the thickness T2b of the recessed portion 40b is smaller than the thickness T1b of the protruding portion 30b.

[0063] In the guide wire 1b of this embodiment described above, the recess 40b has a linear shape that extends spirally along the longitudinal direction of the core shaft 10. As a result, the engagement portion between the recess 40b and the resin coating 50 is formed along the longitudinal direction of the core shaft 10, and the adhesion between the core shaft 10 and the resin coating 50 is further improved.

[0064] 11 is an explanatory diagram illustrating a guidewire 1c of a fourth embodiment. The guidewire 1c differs from the guidewire 1 of the first embodiment in that the first coating 20c does not have the recess 40. Description of the aspects of the guidewire 1c that are common to the guidewire 1 will be omitted.

[0065] 12 is an explanatory diagram illustrating a longitudinal cross section of a guidewire 1c according to a fourth embodiment. The first coating 20c of the guidewire 1c includes a convex portion 30c formed continuously along the longitudinal direction of the core shaft 10. The first coating 20c covers a part of the tapered portion 12 and the outer periphery of the second straight portion 13 of the core shaft 10.

[0066] Fig. 13 is an explanatory diagram illustrating a portion of the appearance of the first coating 20. Fig. 14 is an explanatory diagram illustrating a portion of a longitudinal cross section of the core shaft 10 of the guide wire 1c according to the fourth embodiment. The film thickness of the protrusions 30c in this embodiment is referred to as the "film thickness T1c." The film thickness T1c of the protrusions 30c is approximately constant along the longitudinal direction of the core shaft 10.

[0067] FIGS. 15 and 16 are scanning electron microscope (SEM) photographs of the first coating 20c of the fourth embodiment. FIG. 15 is an SEM photograph of the first coating 20c of the fourth embodiment, observed at 100x magnification. FIG. 16 is an SEM photograph of the first coating 20c of the fourth embodiment, observed at 1000x magnification. FIGS. 15 and 16 show a portion of the first coating 20c formed by laser heating on the outer periphery of a core shaft 10 (FIG. 2) made of a stainless steel alloy. In the core shaft 10 shown in FIGS. 15 and 16, the surface of the core shaft 10 was irradiated with a laser adjusted to an output level that did not significantly evaporate the outer periphery of the core shaft 10, thereby heating the outer periphery of the core shaft 10, thereby forming the first coating 20c. In FIGS. 15 and 16, the fine irregularities of the convex portions 30c are depicted as being closer to black as the concave portions become deeper, and closer to white as the convex portions become taller. In the guide wire 1c described above, the adhesion between the core shaft 10 and the resin coating 50 can also be improved.

[0068] 17 is an explanatory diagram illustrating a portion of a longitudinal cross section of a guidewire 1d according to a fifth embodiment. The guidewire 1d according to the fifth embodiment differs from the guidewire 1 according to the first embodiment in that it includes a second coating 80, which will be described later. A description of the aspects of the guidewire 1d that are common to the guidewire 1 will be omitted.

[0069] The guide wire 1d has a core shaft 10, a first coating 20, a resin coating 50, and a coil 60. The guide wire 1d further has a second coating 80. The second coating 80 is a thin film that covers the outer periphery of the wire 61. In this embodiment, the second coating 80 covers a portion of the wire 61. The tip end of the wire 61 is not covered by the second coating 80. The rear end of the wire 61 is not covered by the second coating 80. The resin coating 50 covers the outer periphery of the second coating 80. The second coating 80 is a film-like oxide formed when the metal material contained in the wire 61 combines with oxygen. That is, the second coating 80 in this embodiment is an oxide coating formed by oxidizing the surface of the wire 61.

[0070] The surface roughness of the second coating 80 (hereinafter referred to as "surface roughness S3") is greater than the surface roughness of the wire 61 (hereinafter referred to as "surface roughness S4"). In other words, when the relationship between the surface roughness S3 and the surface roughness S4 is expressed by an inequality sign, S3 > S4. For example, the surface roughness S3 of the second coating 80 in this embodiment, expressed by the root mean square height (Sq), is 0.01 μm to 10 μm. On the other hand, the surface roughness S4 of the wire 61 in this embodiment, expressed by the root mean square height (Sq), is approximately 0.001 μm to 5 μm. The surface roughness S4 of the wire 61 in this embodiment refers to the surface roughness of the portions of the wire 61 that are not covered with the second coating 80. In this embodiment, this refers to the surface roughness of the portions of the wire 61 that are not covered with the second coating 80 and are located at the front and rear ends.

[0071] The guidewire 1d of the present embodiment described above includes a core shaft 10, a first coating 20 covering the outer periphery of the core shaft 10, and a resin coating 50 covering the outer periphery of the first coating 20. The guidewire 1d further includes a coil 60 including strands of wire 61 wound helically around the outer periphery of the core shaft 10, and a second coating 80 covering the outer periphery of the strands of wire 61. The resin coating 50 covers the outer periphery of the second coating 80, and the surface roughness of the second coating 80 is greater than the surface roughness of the strands of wire 61. The contact area between the second coating 80 and the resin coating 50 is greater than the contact area between the outer periphery of the strands of wire 61 and the resin coating 50 when the resin coating 50 is formed directly on the outer periphery of the strands of wire 61 without the second coating 80. This improves adhesion between the strands of wire 61 and the resin coating 50 of the guidewire 1d. In other words, the wires 61 and the resin coating 50 of the guide wire 1d are bonded more firmly, and peeling of the resin coating 50 from the wires 61 can be suppressed.

[0072] The second coating 80 is an oxide coating formed by oxidizing the surface of the wire 61. This makes it possible to form the second coating 80 relatively easily.

[0073] <Modifications> The technology disclosed in this specification is not limited to the above-described embodiments, and can be implemented in various forms without departing from the spirit thereof. For example, the following modifications are also possible.

[0074] In the guide wire 1 of the first embodiment, the recesses 40 are formed along the circumferential direction of the core shaft 10. The recesses do not have to be formed around the entire circumferential circumference of the core shaft, but may be formed over half the circumferential length of the core shaft. The recesses are not limited to being linear, and may be formed in, for example, a dotted shape. Even in these cases, the adhesion between the core shaft and the resin coating can be improved.

[0075] The coil 60 of the guidewire (1, 1c, 1d) of the first, fourth, and fifth embodiments covers the outer periphery of the first straight portion 11 and a portion of the outer periphery of the tapered portion 12. However, the length of the coil can be set arbitrarily, and for example, it may be long enough to cover only a portion of the distal end of the first straight portion. The guidewire does not necessarily have to have a coil, but may instead have a core shaft, an oxide coating covering the outer periphery of the core shaft, and a resin coating. In this case, by forming an oxide coating on the entire core shaft, including the first straight portion, the tapered portion, and the second straight portion, and then forming a resin coating on the outer periphery of the oxide coating, the adhesion of the resin coating to the core shaft can be improved.

[0076] The first coating does not necessarily have to be an oxide coating, and similarly, the second coating does not necessarily have to be an oxide coating.

Claims

1. A guidewire, A core shaft; a first coating covering an outer periphery of the core shaft, the first coating having a surface roughness greater than a surface roughness of the core shaft; a resin coating covering the outer periphery of the first coating.

2. 2. The guidewire of claim 1, The guidewire, wherein the first coating has a recess recessed toward the radially inner side of the core shaft.

3. 3. The guidewire according to claim 2, The guide wire, wherein the recess is linear and extends along the circumferential direction of the core shaft.

4. 3. The guidewire according to claim 2, The guide wire, wherein the recess is linear and extends along the longitudinal direction of the core shaft.

5. 3. The guidewire according to claim 2, The guide wire, wherein the recess is a line extending spirally along the longitudinal direction of the core shaft.

6. The guidewire according to any one of claims 2 to 5, the first coating further includes a protrusion adjacent to the recess as viewed in the radial direction of the core shaft and positioned radially outward of the recess, The guide wire, wherein the first coating has an unevenness at the interface between the recessed portion and the protruding portion when viewed in the radial direction of the core shaft.

7. 2. The guidewire of claim 1, The guide wire, wherein the first coating is an oxide coating formed by oxidizing the surface of the core shaft.

8. 10. The guidewire of claim 1, further comprising: a coil including a wire wound in a spiral shape around the outer periphery of the core shaft; a second coating covering the outer periphery of the wire, the resin coating covers the outer periphery of the second coating, The guide wire, wherein the surface roughness of the second coating is greater than the surface roughness of the wire.

9. 9. The guidewire of claim 8, The guide wire, wherein the second coating is an oxide coating formed by oxidizing the surface of the wire.

10. A guide wire as described in claim 2, A guide wire, wherein a portion of the recess is spherical when viewed in the radial direction of the core shaft.

11. The guide wire according to claim 1, further comprising: a coil including a wire wound in a spiral shape around the outer periphery of the core shaft; A guide wire in which the first coating covers the outer periphery of a portion of the core shaft located rearward of the rear end of the coil, but does not cover the outer periphery of a portion of the core shaft located inside the coil.