Catheter tube

Abstract

To provide a catheter tube which ensures a cross-sectional area required for the auxiliary inner tube thereof, and furthermore has high robustness.SOLUTION: A catheter tube 1 is provided, comprising: a main inner tube 11; a plurality of auxiliary inner tubes 12a, 12b which are arranged in parallel to the main inner tube 11 and each of which has a cross-sectional area smaller than that of the main inner tube 11 in a transverse plane view; and an outer layer 13 which is formed of resin having fusion temperature lower than fusion temperature of resin forming the main inner tube 11 and fusion temperature of resin forming the plurality of the auxiliary inner tubes 12a, 12b and covers the main inner tube 11 and the plurality of the auxiliary inner tubes 12a, 12b. Two neighboring auxiliary inner tubes 12a, 12b in the plurality of the auxiliary inner tubes 12a, 12b are in contact with each other.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a catheter tube having a plurality of lumens.

Background Art

[0002] Conventionally, a catheter tube having a plurality of lumens, so-called a multi-lumen tube, has been used for a balloon catheter or the like. For example, Patent Document 1 discloses a medical multi-lumen tube in which a first inner layer tube (main inner tube) made of a first resin is coated with an outer layer, and a second inner layer tube (sub inner tube) made of a second resin is disposed within the outer layer. When such a multi-lumen tube is applied to an occlusion balloon catheter, the first inner layer tube (main inner tube) functions as a main lumen tube through which a guide wire or another catheter or the like is inserted, and the second inner layer tube (sub inner tube) functions as an inflation lumen tube through which a gas or a fluid for expanding and contracting the balloon flows.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a catheter tube having a main inner tube and a sub inner tube, the sub inner tube is disposed within an outer layer that coats the main inner tube. However, in order to secure a space for disposing the sub inner tube, it is not possible to simply increase the cross-sectional area of the outer layer. On the other hand, depending on the use of the sub inner tube, a certain cross-sectional area is also required for the lumen of the sub inner tube. For example, when the sub inner tube functions as an inflation lumen tube, it is necessary to make the cross-sectional area of the sub inner tube relatively large in order to shorten the time required for deflating the balloon.

[0005] Given the limited space for arranging the secondary inner tubes, one approach to securing the cross-sectional area of ​​the lumen of the secondary inner tubes is to increase the overall cross-sectional area of ​​the secondary inner tubes by providing multiple secondary inner tubes within the outer layer, as shown in Figure 6 of Reference 1. However, providing multiple secondary inner tubes within the outer layer can lead to misalignment (phase shift) during assembly, resulting in poor assembly accuracy and a deformation of the catheter tube's shape, thus reducing the robustness of the catheter tube.

[0006] This invention has been made in view of these points, and aims to provide a highly robust catheter tube while ensuring the required cross-sectional area for the secondary inner tube. [Means for solving the problem]

[0007] To achieve the above objective, the present invention provides a catheter tube comprising: a main inner tube; a plurality of sub-inner tubes arranged in parallel with the main inner tube and having a smaller cross-sectional area than the main inner tube in a cross-sectional view; and an outer layer covering the main inner tube and the plurality of sub-inner tubes, formed of a resin having a melting temperature lower than the melting temperature of the resin forming the main inner tube and the melting temperature of the resin forming the plurality of sub-inner tubes, wherein two adjacent sub-inner tubes in the plurality of sub-inner tubes are in contact with each other (Invention 1).

[0008] According to this invention (Invention 1), even if the outer layer has only a limited cross-sectional area, by arranging multiple sub-internal tubes within the outer layer, it is possible to secure the required cross-sectional area for the sub-internal tubes as a whole while making the shape of each sub-internal tube less prone to deformation. Furthermore, because two adjacent sub-internal tubes in the multiple sub-internal tubes are in contact with each other, the occurrence of misalignment during assembly can be suppressed, allowing for highly accurate assembly, and as a result, a highly robust catheter tube can be manufactured.

[0009] In the above invention (Invention 1), it is preferable that the two adjacent sub-internal tubes are in contact with each other at a position closer to the main internal tube in a cross-sectional view (Invention 2).

[0010] According to this invention (Invention 2), since multiple sub-internal tubes can be arranged along the outer circumference of the main internal tube, multiple sub-internal tubes can be efficiently arranged in the limited space within the outer layer.

[0011] In the above inventions (Inventions 1 and 2), a coating film covering the plurality of sub-internal tubes may be provided (Invention 3).

[0012] According to this invention (Invention 3), the integration of multiple secondary inner tubes can be enhanced by the coating film, thereby further increasing the robustness of the catheter tube.

[0013] In the above invention (Invention 3), the coating film may be made of a resin having a melting temperature lower than the melting temperature of the resin forming the main inner tube and the melting temperatures of the resins forming the plurality of sub-inner tubes (Invention 4). Furthermore, in the above inventions (Inventions 3 and 4), the coating film may be made of a resin having a melting temperature higher than the melting temperature of the resin forming the outer layer (Invention 5).

[0014] In the above invention (Invention 3-5), the coating film may have a slit formed along the axial direction at a position away from the main inner tube in a cross-sectional view (Invention 6).

[0015] According to this invention (Invention 6), the presence of slits makes it easier to arrange multiple secondary inner tubes along the outer circumference of the main inner tube, even if the covering film covers multiple secondary inner tubes. This enhances the robustness of the catheter tube while efficiently arranging multiple secondary inner tubes within the limited space of the outer layer.

[0016] In the above inventions (Inventions 1-6), it is preferable that the plurality of sub-internal tubes are integrated (Invention 7).

[0017] According to such an invention (Invention 7), since a plurality of sub-inner tubes are integrated, it is possible to further suppress the occurrence of displacement during assembly.

[0018] In the above invention (Invention 7), the plurality of sub-inner tubes may be integrated by fixing two adjacent sub-inner tubes to each other (Invention 8), or the plurality of sub-inner tubes may be integrated by sharing a part of the tube walls of two adjacent sub-inner tubes (Invention 9).

Effect of the Invention

[0019] According to the present invention, it is possible to provide a catheter tube with high robustness while ensuring the cross-sectional area required for the sub-inner tube.

Brief Description of the Drawings

[0020] [Figure 1] It is an explanatory diagram showing the structure of a catheter using a catheter tube according to an embodiment of the present invention. [Figure 2] It is an explanatory diagram showing a cross-section (A-A cross-section in FIG. 1) of the catheter tube according to the embodiment. [Figure 3] It is an explanatory diagram showing a cross-section of the catheter tube of Modification 1. [Figure 4] It is an explanatory diagram showing a cross-section of the catheter tube of Modification 2. [Figure 5] It is an explanatory diagram showing a cross-section of the catheter tube of Modification 3. [Figure 6] It is an explanatory diagram showing a cross-section of the catheter tube of Modification 4. [Figure 7] It is an explanatory diagram showing a cross-section of the catheter tube of Modification 5. <x [Figure 8] It is an explanatory diagram showing a cross-section of the catheter tube of Modification 6. [Figure 9] It is an explanatory diagram showing a cross-section of the catheter tube of Modification 7. [Figure 10] It is an explanatory diagram showing a cross-section of the catheter tube of Modification 8. [Modes for carrying out the invention]

[0021] Embodiments of the present invention will be described below with reference to the drawings. Figure 1 is an explanatory diagram showing the structure of a catheter 10 using the catheter tube 1 according to this embodiment, and Figure 2 is an explanatory diagram showing a cross-section of the catheter tube 1 (section AA in Figure 1). It should be noted that the present invention is not limited to the embodiments described below, and the embodiments described are merely examples to explain the technical features of the present invention. Furthermore, the shapes and dimensions shown in each drawing are shown only to facilitate understanding of the content of the present invention and do not accurately reflect the actual shapes and dimensions.

[0022] In this specification, "tip side" means the direction along the axial direction of the catheter tube 1 constituting the catheter 10, and the direction in which the catheter 10 advances toward the treatment site. "Proximal side" means the direction along the axial direction of the catheter tube 1 constituting the catheter 10, and the direction opposite to the tip side. Furthermore, "tip" refers to the tip end of any member or part, and "proximal end" refers to the proximal end of any member or part. In addition, "tip portion" refers to the portion of any member or part that includes the tip and extends from the tip toward the proximal end to the middle of the member, etc., and "proximal end portion" refers to the portion of any member or part that includes the proximal end and extends from this proximal end toward the tip to the middle of the member, etc. In Figure 1, the left side of the illustration is the "tip side" that is inserted into the body, and the right side of the illustration is the "proximal side" that is manipulated by the operator.

[0023] As shown in Figure 1, the catheter 10 comprises a long catheter tube 1, a tip 2 attached to the tip end of the catheter tube 1, a balloon 3 provided between the tip 2 and the catheter tube 1, and a connector 4 connected to the proximal end of the catheter tube 1. The catheter 10 is a balloon catheter used to diagnose or treat stenosis or occlusion, and is used, for example, when inserted into a blood vessel of the heart where a stenosis has formed to widen the stenosis within the blood vessel. In this embodiment, the catheter 10 using the catheter tube 1 is described as a balloon catheter, but the catheter tube of the present invention is not limited to this, and may be applied to catheters without balloons, dilators, endoscopes, etc.

[0024] As shown in Figure 2, the catheter tube 1 is a long tubular member having multiple lumens inside, and comprises a main inner tube 11, two secondary inner tubes 12a and 12b having a smaller cross-sectional area than the main inner tube 11 in a cross-sectional view, and an outer layer 13 covering the main inner tube 11 and the two secondary inner tubes 12a and 12b. The main inner tube 11 is composed of an inner layer tube 111 having a roughly circular lumen in a cross-sectional view, and a reinforcing body 112 arranged on the outer circumference of the inner layer tube 111. The two secondary inner tubes 12a and 12b each have a roughly rectangular lumen in a cross-sectional view and are covered by a single coating film 14 in a contact state. The two secondary inner tubes 12a and 12b are both arranged in parallel with the main inner tube 11, that is, the main inner tube 11 and the two secondary inner tubes 12a and 12b are arranged along the same axial direction (the longitudinal direction of the catheter tube 1).

[0025] The tip 2 is located at the tip of the catheter 10 and has an opening (not shown) that communicates with the lumen of the inner layer tube 111 of the main inner tube 11.

[0026] Balloon 3 is positioned between the multi-lumen tube 10 and the tip 2, and the internal space of balloon 3 is in communication with the lumens of the two secondary inner tubes 12a and 12b.

[0027] Connector 4 is a Y-shaped connector having a main port 41 having an opening (not shown) that communicates with the lumen of the inner layer tube 111 of the main inner tube 11, and a side port 42 having an opening (not shown) that communicates with the lumen of the sub-inner tubes 12a and 12b, and is connected to the base end of the multi-lumen tube 10.

[0028] Catheter 10 can, for example, guide a guidewire or other catheter inserted through the opening of the main port 41 of connector 4, through the inside of the main inner tube 11 to the opening of the tip 2. Catheter 10 can also supply fluid to the internal space of balloon 3 through the opening of the side port 42 of connector 4 via the secondary inner tubes 12a and 12b.

[0029] The inner layer tube 111 of the main inner tube 11 is a tube formed of resin, and a lumen is formed on its inside into which a guide wire or other catheter is inserted. The resin material forming the inner layer tube 111 is not particularly limited, but a resin with good sliding properties with other components is preferred. Examples include fluororesins such as PTFE (polytetrafluoroethylene), PVDF (polyvinylidene fluoride), PFA (perfluoroalkoxyalkane), FEP (perfluoroethylenepropene), and ETFE (ethylenetetrafluoroethylene), as well as PE (polyethylene) and PP (polypropylene). The outer diameter of the inner layer tube 111 is configured to be larger than the outer diameter of the secondary inner tubes 12a and 12b, which will be described later.

[0030] The reinforcing body 112, which is arranged on the outer circumference of the inner layer pipe 111, is, for example, a braided body (metal blade layer) formed by weaving multiple strands of wire into a mesh-like structure. The reinforcing body 112 may cover the entire inner layer pipe 111 or it may cover only a portion of the inner layer pipe 111. Alternatively, a resin outer layer pipe (not shown) with the reinforcing body 112 embedded in it may be arranged on the outer circumference of the inner layer pipe 111.

[0031] The secondary inner tubes 12a and 12b are tubes formed of resin, and a lumen is formed inside them for the flow of fluids such as gases and liquids. The resin material used to form the secondary inner tubes 12a and 12b is not particularly limited, but a resin with high mechanical strength and high crush resistance is preferred. Examples include PEEK (polyether ether ketone), PI (polyimide), PEI (polyetherimide), and PPS (polyphenylene sulfide). The secondary inner tubes 12a and 12b may be formed of the same type of resin as the inner layer tube 111 of the main inner tube 11, or they may be formed of a different resin. The outer diameter of the secondary inner tubes 12a and 12b is configured to be smaller than the outer diameter of the inner layer tube 111 of the main inner tube 11. It should be noted that the two secondary inner tubes 12a and 12b do not necessarily have to be made of the same resin material, nor do they need to be the same size or shape.

[0032] The outer layer 13 is formed of resin and covers the main inner tube 11 (inner layer tube 111, reinforcing body 112) and the secondary inner tubes 12a and 12b. The resin material forming the outer layer 13 is not particularly limited, but examples include polyamide, polyamide elastomer, polyester, polyurethane, polyurethane elastomer, etc. The outer layer 13 may be formed of a single resin material, or it may be formed in multiple regions using multiple resin materials with different properties. Furthermore, tungsten powder may be included in the resin forming the outer layer 13, and the hardness of the resin may be changed depending on the amount of tungsten powder. By including tungsten powder, which is a radiopaque powder, in the resin forming the outer layer 13, the position of the catheter 10 can be accurately determined by the operator, such as a physician, during coronary angiography.

[0033] The coating film 14 is formed of resin and covers the two sub-internal tubes 12a and 12b in a state of contact and integration. That is, the two sub-internal tubes 12a and 12b are integrated by the coating film 14 in such a state that adjacent sub-internal tubes 12a and 12b are in contact with each other. The resin forming the coating film 14 has a melting temperature higher than the resin forming the outer layer 13. The resin material forming the coating film 14 is not particularly limited, but a resin with good adhesion and bonding between the coating film 14 and the outer layer 13 is preferred, and examples include polyurethane, polyamide elastomer, modified polyethylene, etc.

[0034] In this embodiment, the catheter tube 1 is equipped with two secondary inner tubes 12a and 12b, which are in contact with each other in a cross-sectional view at a position close to the main inner tube 11. The fact that two adjacent secondary inner tubes 12a and 12b are in contact with each other in a cross-sectional view at a position close to the main inner tube 11 means that the two secondary inner tubes 12a and 12b can be arranged along the outer circumference of the main inner tube 11, allowing multiple secondary inner tubes 12a and 12b to be efficiently arranged in the limited space within the outer layer 13. Furthermore, in this embodiment, the cohesive film 14 enhances the unity of the multiple secondary inner tubes 12a and 12b, thereby further increasing the robustness of the catheter tube 10.

[0035] The state in which the two sub-internal tubes 12a and 12b are in contact may be maintained simply by covering the two sub-internal tubes 12a and 12b with the coating film 14, or it may be maintained by fixing two adjacent sub-internal tubes 12a and 12b together using known fixing means such as adhesive or welding. In this embodiment, the two adjacent sub-internal tubes 12a and 12b are in contact only at a position closer to the main internal tube 11 in a cross-sectional view, but it is not necessary that they be in contact in this manner; it is sufficient that the two adjacent sub-internal tubes 12a and 12b are in contact with each other so that misalignment does not occur during assembly. More preferably, the two adjacent sub-internal tubes 12a and 12b are integrated while in contact with each other.

[0036] The thickness of the coating film 14 is not particularly limited, but it is preferable that it be thinner than the thickness of the walls of the two sub-internal tubes 12a and 12b in order to efficiently arrange the two sub-internal tubes 12a and 12b. In this embodiment, the coating film 14 is configured to have a uniform thickness throughout, but it is not limited to this, and for example, the coating film 14 may be formed such that the thickness of the part of the coating film 14 farther from the main internal tube 11 is thinner than the thickness of the part closer to the main internal tube 11. When the coating film 14 is formed in this way, the part of the coating film 14 farther from the main internal tube 11 is more stretchable than the part closer to the main internal tube 11, making it easier to arrange the two sub-internal tubes 12a and 12b along the outer circumference of the main internal tube 11.

[0037] Furthermore, if the points where the two auxiliary inner tubes 12a and 12b are in contact are defined as contact points, these contact points may be provided continuously or intermittently along the longitudinal direction of the catheter tube 1. Providing contact points intermittently along the longitudinal direction of the catheter tube 1 means that there are also points where the two auxiliary inner tubes 12a and 12b are not in contact. If the points where the two auxiliary inner tubes 12a and 12b are not in contact are defined as gaps, then if gaps exist along the longitudinal direction of the catheter tube 1, the movement of the two auxiliary inner tubes 12a and 12b will not be as constrained by each other, thereby ensuring the flexibility of the catheter tube 1.

[0038] With this type of catheter tube 1, even if the outer layer 13 has a limited cross-sectional area, by arranging multiple sub-internal tubes 12a and 12b within the outer layer 13, it is possible to secure the required cross-sectional area for the sub-internal tubes as a whole while making the shape of each sub-internal tube 12a and 12b less prone to deformation. Furthermore, since the multiple sub-internal tubes 12a and 12b are integrated in such a way that adjacent sub-internal tubes 12a and 12b remain in contact with each other, the occurrence of misalignment during assembly can be suppressed, allowing for accurate assembly, and as a result, a highly robust catheter tube 1 can be manufactured.

[0039] Here, we will explain the relationship between the melting temperatures of the resins that form the main inner tube 11 (its inner layer tube 111), the secondary inner tubes 12a and 12b, the outer layer 13, and the coating film 14. As mentioned above, the resin that forms the outer layer 13 has a lower melting temperature than the resin that forms the main inner tube 11 (its inner layer tube 111) and the resins that form the two secondary inner tubes 12a and 12b. This is because, in the process of manufacturing the catheter tube 1, the outer layer 13 is formed to cover the main inner tube 11 and the secondary inner tubes 12a and 12b while the secondary inner tubes 12a and 12b are assembled to the main inner tube 11. This is to prevent the inner layer tube 111 of the main inner tube 11 and the secondary inner tubes 12a and 12b from melting during the formation of the outer layer 13.

[0040] Furthermore, for the same reasons, it is preferable that the resin forming the coating film 14 has a melting temperature lower than the melting temperature of the resin forming the main inner tube 11 (and its inner layer tube 111) and the melting temperature of the resin forming the two sub-inner tubes 12a and 12b. Moreover, it is preferable that the resin forming the coating film 14 has a melting temperature higher than the melting temperature of the resin forming the outer layer 13. This is to prevent the two sub-inner tubes 12a and 12b, whose contact state is maintained by being covered with the coating film 14, from separating too much when the coating film 14 is formed, resulting in a state where the sub-inner tubes 12a and 12b do not come into contact with each other.

[0041] For example, the melting temperature of the resin forming the main inner tube 11 is preferably in the range of 180 to 420°C, the melting temperature of the resin forming the secondary inner tubes 12a and 12b is preferably in the range of 340 to 410°C, the melting temperature of the resin forming the outer layer 13 is preferably in the range of 180 to 270°C, and the melting temperature of the resin forming the coating film 14 is preferably in the range of 180 to 240°C.

[0042] The manufacturing method for the catheter tube 1 having the above structure will be described below. First, the resin material of the inner layer tube 111 of the main inner tube 11 is coated onto a metal core using an extrusion molding machine or the like, or the metal core is coated or immersed in a solution in which the resin material of the inner layer tube 111 is dissolved, and then dried to form the inner layer tube 111 of the main inner tube 11. The reinforcing body 112 is wrapped around this inner layer tube 111 to form the main inner tube 11.

[0043] Next, similar to the inner layer tube 111 of the main inner tube 11, the resin material of the sub-inner tubes 12a and 12b is coated onto a metal core using an extrusion molding machine or the like, or the metal core is coated or immersed in a solution in which the resin material of the sub-inner tubes 12a and 12b is dissolved, and then dried to form the sub-inner tubes 12a and 12b. The coating film 14 that covers the sub-inner tubes 12a and 12b may be formed by coating or immersing the sub-inner tubes 12a and 12b in a solution in which the resin material of the coating film 14 is dissolved, and then drying them, or the resin material of the coating film 14 can be extruded at the same time as the sub-inner tubes 12a and 12b are formed by extrusion molding.

[0044] A catheter tube 1 can be manufactured by arranging the sub-internal tubes 12a and 12b, which are covered with a coating film 14, along the formed main internal tube 11, covering it with a tube made of resin material for the outer layer 13, and then heating and heat-welding it. Alternatively, the catheter tube 1 can also be manufactured by using the sub-internal tubes 12a and 12b, which are covered with a coating film 14, along the main internal tube 11 as a pseudo-core, and then covering it with the resin material for the outer layer 13 by extrusion molding.

[0045] Although the catheter tube according to the present invention has been described above with reference to the drawings, the present invention is not limited to the above embodiments and various modifications are possible. Modifications of the catheter tube 1 according to the above embodiment will be described below.

[0046] <Example 1> In the catheter tube 1A of the modified example 1, as shown in Figure 3, the covering membrane 14A has a slit 141 formed along the axial direction at a position away from the main inner tube 11 in a cross-sectional view, that is, close to the outer circumference of the catheter tube 1A. The presence of the slit 141 makes it easier to position the two secondary inner tubes 12a and 12b even when the covering membrane 14A covers them, so as to be closer to the outer circumference of the main inner tube 11. This increases the robustness of the catheter tube 1A while efficiently arranging multiple secondary inner tubes 12a and 12b in the limited space within the outer layer 13.

[0047] The slits 141 may be provided continuously or intermittently along the longitudinal direction of the catheter tube 1A. Alternatively, the slits 141 may be formed by covering the two sub-internal tubes 12a and 12b with a tubular coating 14 and then forming the slits 141 on the coating 14 with a cutter or the like, or by wrapping the two sub-internal tubes 12a and 12b with a sheet-like coating 14 and then fixing the coating 14 to the sub-internal tubes 12a and 12b, leaving the slits 141 portion uncovered.

[0048] <Modification 2> In the catheter tube 1B of the modified example 2, as shown in Figure 4, both the secondary inner tubes 12Ba and 12Bb have a roughly elliptical lumen in cross-sectional view and are covered by a single covering membrane 14B. The two secondary inner tubes 12Ba and 12Bb are in contact at a position closer to the main inner tube 11 in cross-sectional view. Thus, the cross-sectional shape of the secondary inner tubes 12Ba and 12Bb is not limited to a roughly rectangular shape, but may be roughly elliptical or have other shapes. The covering membrane 14B may cover the secondary inner tubes 12Ba and 12Bb in a manner that follows the outer circumference of the two secondary inner tubes 12Ba and 12Bb.

[0049] <Variation 3> In the catheter tube 1C of the modified example 3, as shown in Figure 5, three secondary inner tubes 12Ca, 12Cb, and 12Cc are covered by a single coating membrane 14C. Each of the secondary inner tubes 12Ca, 12Cb, and 12Cc has a roughly rectangular lumen in cross-sectional view. Of the three secondary inner tubes 12Ca, 12Cb, and 12Cc, two secondary inner tubes 12Ca and 12Cb are in contact with the main inner tube 11 in cross-sectional view, and two secondary inner tubes 12Cb and 12Cc are also in contact with the main inner tube 11 in cross-sectional view. Thus, the number of secondary inner tubes 12Ca, 12Cb, and 12Cc is not limited to two, but may be three or more. Also, the shapes of the multiple secondary inner tubes 12Ca, 12Cb, and 12Cc may be the same, or they may be different.

[0050] <Modification 4> In the catheter tube 1D of the modified example 4, as shown in Figure 6, two secondary inner tubes 12Da and 12Db are covered by one coating membrane 14Da, and two secondary inner tubes 12Dc and 12Dd are covered by another coating membrane 14Db. The secondary inner tubes 12Da, 12Db, 12Dc, and 12Dd all have a roughly rectangular lumen in cross-sectional view, and the two secondary inner tubes 12Da and 12Db are in contact near the main inner tube 11 in cross-sectional view, and the two secondary inner tubes 12Dc and 12Dd are also in contact near the main inner tube 11 in cross-sectional view. Thus, the number of secondary inner tubes 12Da, 12Db, 12Dc, and 12Dd is not particularly limited to two, and there may be two or more assemblies of secondary inner tubes covered by coating membranes 14Da and 14Db.

[0051] <Modification 5> In the catheter tube 1E of Modified Example 5, as shown in Figure 7, the two secondary inner tubes 12Ea and 12Eb are arranged in contact with each other at a position close to the main inner tube 11 in a cross-sectional view, but the two secondary inner tubes 12Ea and 12Eb are not covered by a coating film. In this way, even without a coating film, if the contact state of the two secondary inner tubes 12Ea and 12Eb is maintained, it is possible to provide a highly robust catheter tube while ensuring the required cross-sectional area of ​​the secondary inner tubes. Alternatively, the two secondary inner tubes 12Ea and 12Eb may be fixed together using known means such as adhesive or welding to maintain the contact state.

[0052] <Variation 6> In the catheter tube 1F of the modified example 6, as shown in Figure 8, two adjacent secondary inner tubes 12Fa and 12Fb share a portion of their tube walls, thereby integrating multiple secondary inner tubes 12Fa and 12Fb. Specifically, two integrated secondary inner tubes 12Fa and 12Fb are formed by erecting a flat, plate-shaped tube wall 122 within a secondary inner tube 121 having a roughly rectangular lumen in a flattened cross-sectional view. In this way, even without a coating, if the contact state is maintained by the integration of the two secondary inner tubes 12Fa and 12Fb, it is possible to provide a highly robust catheter tube while ensuring the required cross-sectional area of ​​the secondary inner tubes.

[0053] <Example 7> In the catheter tube 1G of the modified example 7, as shown in Figure 9, two adjacent secondary inner tubes 12Ga and 12Gb share a portion of the tube wall, thereby integrating multiple secondary inner tubes 12Ga and 12Gb. Specifically, the two secondary inner tubes 12Ga and 12Gb are formed as a single spectacle-shaped secondary inner tube 124 having two substantially elliptical lumens 123a and 123b in cross-sectional view, thereby forming two integrated secondary inner tubes 12Ga and 12Gb. In this way, even without a coating film, if the contact state is maintained by the integration of the two secondary inner tubes 12Ga and 12Gb, it is possible to provide a highly robust catheter tube while ensuring the required cross-sectional area of ​​the secondary inner tubes.

[0054] <Differentiation Example 8> In the catheter tube 1H of the modified example 8, as shown in Figure 10, two adjacent secondary internal tubes 12Ha and 12Hb share a portion of the tube wall, thereby integrating multiple secondary internal tubes 12Ha and 12Hb. Specifically, the two secondary internal tubes 12Ha and 12Hb are formed as a single secondary internal tube 126, where the corners of the two roughly rectangular lumens 125a and 125b near the main internal tube 11 are connected in cross-sectional view, thereby forming two integrated secondary internal tubes 12Ha and 12Hb. In this way, even without a coating, if the contact state is maintained by the integration of the two secondary internal tubes 12Ha and 12Hb, it is possible to provide a highly robust catheter tube while ensuring the required cross-sectional area of ​​the secondary internal tubes. [Explanation of symbols]

[0055] 10 Catheters 1 Catheter tube 11 Outer layer 12 Main inner pipe 13 Reinforcement 14a, 14b Secondary inner canal 2 Tips 3 Balloons 4 connectors

Claims

1. Main internal pipe and Multiple sub-internal tubes are arranged in parallel with the main internal tube and have a smaller cross-sectional area than the main internal tube in a cross-sectional view, An outer layer covering the main inner tube and the plurality of sub-inner tubes, formed from a resin having a melting temperature lower than the melting temperature of the resin forming the main inner tube and the melting temperature of the resin forming the plurality of sub-inner tubes, The system comprises a coating film that covers the plurality of sub-internal tubes, A catheter tube in which two adjacent sub-internal tubes in the aforementioned plurality of sub-internal tubes are in contact with each other.

2. The catheter tube according to claim 1, wherein the two adjacent sub-internal tubes are in contact with each other in a cross-sectional view at a position closer to the main internal tube.

3. The catheter tube according to claim 1, wherein the coating film is made of a resin having a melting temperature lower than the melting temperature of the resin forming the main inner tube and the melting temperatures of the resins forming the plurality of sub-inner tubes.

4. The catheter tube according to any one of claims 1 to 3, wherein the coating film is made of a resin having a melting temperature higher than the melting temperature of the resin forming the outer layer.

5. The catheter tube according to any one of claims 1 to 4, wherein the coating film has a slit formed along the axial direction at a position away from the main inner tube in a cross-sectional view.

6. The catheter tube according to any one of claims 1 to 5, wherein the plurality of sub-internal tubes are integrated.

7. The catheter tube according to claim 6, wherein the plurality of sub-internal tubes are integrated by fixing two adjacent sub-internal tubes together.

8. The catheter tube according to claim 6, wherein the plurality of sub-internal tubes are integrated by two adjacent sub-internal tubes sharing a portion of the tube wall.

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