catheter

Abstract

The present invention provides a catheter that is less likely to deteriorate even when stored for a long period of time. The present invention pertains to a catheter comprising: a catheter tip that has a catheter tip resin layer containing at least 60 mass% of tungsten carbide (WC); a catheter body that has a catheter body resin layer containing at least one second additive selected from the group consisting of antioxidants and light stabilizers; and the catheter tip resin layer. The total value of the contained amount of at least one first additive selected from the group consisting of antioxidants and light stabilizers and contained in the catheter tip resin layer is less than the total value of the contained amount of the second additive in the catheter body resin layer, and the total value of the contained amount of the first additive is not less than 0 mass% but less than 3 mass% with respect to the catheter tip resin layer.

Description

catheter

[0001] The present invention relates to a catheter.

[0002] When treating or diagnosing a stenosis, a catheter is used to insert a medical device into the body and guide it to the target site. To accurately determine the position of the catheter tip when inserting the catheter into the body, the tip of the catheter (catheter tip) typically contains a radiopaque material that enables detection by X-ray. For example, metallic tungsten powder is known as a highly radiopaque material and is used as a catheter tip material (see, for example, Patent Document 1). Resins with amide or ester bonds are commonly used as catheter materials.

[0003] U.S. Pat. No. 5,584,821

[0004] Catheters are not always used immediately, but may be stored for long periods before use. Catheter tips are usually made of resin for their moldability and flexibility, but if tungsten is added to the catheter tip as an X-ray opaque material, there is a risk that the resin may deteriorate.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a catheter in which the resin is unlikely to deteriorate even when stored for a long period of time.

[0006] A catheter according to one embodiment of the present invention has the following configuration: (1) A catheter comprising: a catheter tip having a catheter tip resin layer containing 60% by mass or more of tungsten carbide (WC); and a catheter main body having a catheter main body resin layer containing at least one second additive selected from the group consisting of antioxidants and light stabilizers, wherein the total content of the at least one first additive selected from the group consisting of antioxidants and light stabilizers contained in the catheter tip resin layer is less than the total content of the second additive in the catheter tip main body resin layer, and the total content of the first additive is 0% by mass or more and less than 3% by mass of the catheter tip resin layer.

[0007] (2) The catheter according to (1), wherein the resin contained in the catheter tip resin layer is a resin having an ester bond and / or an amide bond.

[0008] (3) The catheter according to (2), wherein the resin having an ester bond and / or an amide bond includes a polyamide resin.

[0009] (4) The catheter according to any one of (1) to (3), wherein the particle size of the tungsten carbide is 1 to 10 μm.

[0010] (5) A catheter according to any one of (1) to (4), wherein the catheter tip does not contain metallic tungsten (W) alone.

[0011] (6) The catheter according to any one of (1) to (5), wherein the antioxidant is at least one of a phosphorus-based antioxidant, a sulfur-based antioxidant, and a phenol-based antioxidant, and the light stabilizer is at least one of an ultraviolet absorber and a HALS.

[0012] 1 is a diagram showing the overall configuration of a catheter, and FIG. 2 is a schematic cross-sectional view of the vicinity of the junction between the catheter tip and the catheter main body.

[0013] The present invention provides a catheter comprising: a catheter tip having a catheter tip resin layer containing 60% by mass or more of tungsten carbide (WC); and a catheter main body having a catheter main body resin layer containing at least one second additive selected from the group consisting of antioxidants and light stabilizers, wherein the total content of the at least one first additive selected from the group consisting of antioxidants and light stabilizers contained in the catheter tip resin layer is less than the total content of the second additive in the catheter main body resin layer, and the total content of the first additive is 0% by mass or more and less than 3% by mass of the catheter tip resin layer.

[0014] According to the catheter of the present invention, it is possible to provide a catheter in which the risk of resin deterioration even when stored for a long period of time is reduced.

[0015] Metallic tungsten powder is usually used in combination with a resin, and the present inventors speculated that the deterioration of the resin during long-term storage may be due to the accelerated hydrolysis of the ester bond and / or amide bond in the presence of metallic tungsten.

[0016] Metallic tungsten is converted into metallic tungsten (W) and a very small amount of tungsten oxide (WO) by the oxidation reaction expressed by the following formula during the manufacturing process or by oxygen in the air. ３ When this tungsten oxide comes into contact with water, it undergoes a hydration reaction to become tungstic acid, and acidic hydrogen ions (in this specification, "hydrogen ions" and "acidic hydrogen ions" refer to "H ＋ This contributes to the release of hydroxybenzoates (which means "hydrogen peroxide"), i.e., acidification, resulting in a decrease in pH.

[0017]

[0018] In fact, a resin containing metallic tungsten powder (W) (Comparative Example 1, described below), a resin containing tungsten carbide powder (WC) (Example 1, described below), and only the resin were subjected to high temperature and high humidity conditions for a certain period of time, and the pH values ​​before and after the test were compared. Specifically, 1 g of each of the three pellet-shaped resins was added to 5 mL of RO water and stirred before and after a one-week high temperature and high humidity load. The mixture was allowed to stand at room temperature for 24 hours, and then the pH was measured using a pH meter (AS600, manufactured by AS ONE Corporation, 25°C). As a result, the pH values ​​of the resin sample containing no metals and the resin containing tungsten carbide powder of Example 1 did not decrease before and after the high temperature and high humidity load, but the pH value of the resin containing metallic tungsten powder of Comparative Example 1 decreased significantly before and after the high temperature and high humidity load.

[0019] Under acidic conditions, the ester bond and / or amide bond undergoes hydrolysis. Furthermore, as the hydrolysis proceeds, the terminal carboxyl groups of the decomposition products act as acids, which can increase the reaction rate of the hydrolysis.

[0020] Table 1 below shows the results of measuring the molecular weight (in PMMA terms) using GPC for the sample of Comparative Example 1 ((1) sample before loading) and a sample obtained by leaving the sample in a high-temperature, high-humidity environment for a certain period of time ((2) sample after loading). In Table 1, Mn means number-average molecular weight, Mw means weight-average molecular weight, and Mz means z-average molecular weight.

[0021]

[0022] These results show that resins containing metallic tungsten powder undergo decomposition due to high temperature and humidity loads, resulting in low molecular weight components. This decomposition of the resin is thought to be due to hydrolysis of the resin.

[0023] Such hydrolysis may progress gradually over a long period of storage of the catheter, even under normal temperature and humidity conditions, potentially resulting in deterioration of the resin over time.

[0024] The above-mentioned concerns arise particularly in catheter tips in which a relatively large amount of radiopaque material (for example, 60% by mass or more of the total) is blended to enhance the contrast of the tip.

[0025] Based on this knowledge, the present inventors have conducted extensive research and have found that resin deterioration under high temperature and high humidity load conditions can be suppressed by using tungsten carbide (WC) instead of metallic tungsten (W) powder as the radiopaque material. By using tungsten carbide (WC), tungsten oxide (WO) as shown in Formula 1 can be suppressed. ３ ), the subsequent hydration reaction of tungsten oxide is also less likely to proceed, and the suppression of the generation of acidic hydrogen ions prevents a decrease in the pH value, which is thought to result in the suppression of the hydrolysis of ester bonds and / or amide bonds.

[0026] Therefore, the catheter tip does not need to contain antioxidants / light stabilizers that inhibit deterioration of the resin, and the amounts of these additives can be less than those normally required.

[0027] The catheter according to the present invention will be described below with reference to the drawings. In the description of the drawings, the same elements are given the same reference numerals, and duplicate explanations will be omitted. The dimensional proportions in each drawing are exaggerated for the sake of explanation, and may differ from the actual proportions.

[0028] In addition, any combination of two or more of the individual preferred embodiments of the present invention described below is also a preferred embodiment of the present invention and is considered to be disclosed in this specification (i.e., is a lawful basis for amendment).

[0029] Figure 1 is a diagram showing the overall configuration of a catheter 1 of the present invention. In Figure 1, the side of the catheter 1 that is inserted into a living body (the left side of Figure 1) is referred to as the distal end side, the side of the catheter 1 where the hub 30 is located is referred to as the proximal end side, and the direction in which the catheter main body 10 of the catheter 1 extends is referred to as the axial direction. Furthermore, in a cross section (cross section perpendicular to the axis) of the catheter main body 10 with the axial direction of the catheter main body 10 as the reference axis, the direction moving away from or approaching the catheter main body 10 is referred to as the radial direction.

[0030] The catheter 1 has a catheter main body 10 extending in the axial direction, a catheter tip 20 disposed on the distal side of the catheter main body 10, a hub 30 disposed on the proximal side of the catheter main body 10, and a kink-resistant protector (strain relief) 40 disposed between the catheter main body 10 and the hub 30. The catheter main body 10 and the catheter tip 20 may be joined to each other.

[0031] The catheter body 10 is formed of a flexible hollow tubular member. A lumen 10H is formed in the catheter body 10 over the entire length of the catheter body 10. The lumen 10H opens at the distal end of the catheter tip 20.

[0032] Fig. 2 is an enlarged cross-sectional schematic view of the distal end structure of the catheter 1 according to one embodiment of the present invention. As shown in Fig. 2, the catheter 1 is configured as a flexible tubular member having an axially extending lumen, a distal opening communicating with the lumen, and a proximal opening communicating with the lumen.

[0033] The catheter body may have a layered structure in which layers are stacked in the radial direction. The catheter body may include a tubular catheter body resin layer 12 (outer layer), an inner layer 11 disposed on the inner surface of the catheter body resin layer 12, a metal reinforcement layer 13 disposed between the catheter body resin layer 12 and the inner layer 11, and a hydrophilic lubricating layer 14 disposed on the outer surface of the catheter body resin layer 12. Although not limited to the present invention, in the embodiment shown in FIG. 2 , the inner layer 11 and the hydrophilic lubricating layer 14 extend to the distal end of the catheter tip 20. That is, in the embodiment shown in FIG. 2 , the inner layer 11 and the hydrophilic lubricating layer 14 are common to the inner layer and hydrophilic lubricating layer of the catheter tip 20 and may also form a layered structure with the catheter tip resin layer 21. Furthermore, in the catheter tip, the catheter body resin layer 12 (without the inner layer 11 and the hydrophilic lubricating layer 14) may be a single layer, or the catheter body resin layer 12 may be a single layer containing the metal reinforcement layer 13.

[0034] The inner layer 11 is preferably made of a material that provides low friction at least in the portion that comes into contact with a device, such as a treatment catheter or a guidewire, when the device is inserted into the lumen 10H. This configuration allows the device inserted into the catheter to move longitudinally with less sliding resistance, improving operability. Specifically, the inner layer 11 can be made of a fluorine-based resin material, such as polytetrafluoroethylene (PTFE).

[0035] The catheter body resin layer 12 has a hollow tubular shape extending in the axial direction of the catheter body 10. The hydrophilic lubricating layer 14, like the catheter body resin layer 12, has a hollow tubular shape extending in the axial direction of the catheter body 10.

[0036] The presence of the hydrophilic lubricating layer 14 facilitates insertion into a living body. The constituent material of the hydrophilic lubricating layer 14 is not particularly limited, but examples thereof include copolymers of epoxy group-containing monomers such as glycidyl acrylate, glycidyl methacrylate, 3,4-epoxycyclohexylmethyl acrylate, 3,4-epoxycyclohexylmethyl methacrylate, β-methylglycidyl methacrylate, and allyl glycidyl ether with hydrophilic monomers such as N-methylacrylamide, N,N-dimethylacrylamide, and acrylamide; (co)polymers composed of the above hydrophilic monomers; cellulose-based polymeric substances such as hydroxypropyl cellulose and carboxymethyl cellulose; polysaccharides, polyvinyl alcohol, methyl vinyl ether-maleic anhydride copolymer, water-soluble polyamide, poly(2-hydroxyethyl (meth)acrylate), polyethylene glycol, polyacrylamide, polyvinylpyrrolidone, and copolymers of polyvinylpyrrolidone and polyurethane described in U.S. Pat. No. 4,100,309 and Japanese Patent Laid-Open Publication No. 59-19582. These hydrophilic lubricating materials may be used alone or in the form of a mixture of two or more kinds.

[0037] A hub 30 is attached (fixed) to the proximal end of the catheter main body 10. The hub 30 has an inner cavity that communicates with the lumen 10H and has a luer taper formed therein.

[0038] The hub 30 can be used to insert or remove long objects (linear objects) such as guidewires, catheters (e.g., balloon catheters and stent delivery catheters), endoscopes, ultrasound probes, and temperature sensors, and can also be used to inject various liquids such as contrast agents (X-ray contrast agents), medicinal solutions, and physiological saline. The hub 30 can also be connected to other devices, such as a Y-branch connector. The hub 30 can be made of thermoplastic resins such as polycarbonate, polyamide, polysulfone, and polyarylate.

[0039] The catheter is inserted into the body while its position is confirmed under X-ray fluoroscopy. In the present invention, since the catheter tip 20 contains tungsten carbide, which is a radiopaque material, the catheter main body 10 does not necessarily need to contain a radiopaque material. However, a radiopaque material (an X-ray contrast medium) may be blended into the material constituting the catheter main body resin layer 12. Examples of radiopaque materials that can be used include barium sulfate, bismuth oxide, and tungsten. Furthermore, the radiopaque material need not be present throughout the entire length of the catheter main body 10, but may be present only in a portion of the catheter main body 10, such as the distal end of the catheter main body 10 or the catheter tip 20.

[0040] Hereinafter, embodiments for carrying out the present invention will be described in detail. In this specification, the range "X to Y" includes X and Y and means "X or more and Y or less." Unless otherwise specified, operations and measurements of physical properties are carried out under conditions of room temperature (20 to 25°C) and a relative humidity of 40 to 50% RH. A and / or B refers to A, B, or a combination thereof.

[0041] (Catheter) The catheter 1 of the present invention is a long medical device that can be passed through a biological organ and used for the purpose of treating and improving a stricture, or for the purpose of delivering a medical device such as a stent inside the body. Examples of biological organs include, but are not limited to, blood vessels, bile ducts, tracheas, esophagus, other digestive tracts, urethras, ear and nose cavities, and other organs. In one embodiment, the biological organ is a blood vessel, which may be, for example, a coronary artery.

[0042] The catheter 1 of the present invention contains a radiopaque material, which allows the catheter 1 to be visualized under X-ray irradiation using imaging techniques such as X-ray fluoroscopy as the catheter 1 is guided through a blood vessel to a target location. The radiopaque material may be contained in the catheter tip 20 in particular.

[0043] In one embodiment, the catheter 1 is used together with an introducer sheath. In one embodiment, the catheter 1 is used together with an introducer sheath and a guidewire. Here, the introducer sheath is a tubular medical device that is passed from outside the body into the inside of a blood vessel in advance to insert the catheter into the blood vessel, and the guidewire is a medical device that is introduced before inserting the catheter to help guide the catheter to a desired location within the blood vessel. For example, after passing through the introducer sheath, a guidewire is passed through the introducer sheath and inserted through the blood vessel to near the desired location for catheter 1. Thereafter, the catheter 1 is introduced into the blood vessel through a through-hole inside the introducer sheath via the guidewire, and then guided through the blood vessel along the guidewire to the desired location. After that, the guidewire is removed, allowing the catheter 1 to guide a medical device or the like to the desired location.

[0044] (Catheter Tip) The catheter tip 20 is made of a material that is more flexible than the catheter main body 10. The catheter tip 20 is also called a distal tip, and has the functions of suppressing damage to a biological lumen such as a blood vessel and improving insertability into a stenosis formed in a blood vessel. In Fig. 2, the catheter tip 20 has a tapered shape in which the outer diameter decreases toward the distal end, but the outer diameter may be substantially constant up to the distal end.

[0045] The catheter tip has a catheter tip resin layer 21. The catheter tip resin layer 21 contains a resin having an ester bond and / or an amide bond (a resin having an ester bond, an amide bond, or a combination thereof), tungsten carbide, and, optionally, at least one additive (first additive) selected from the group consisting of an antioxidant and a light stabilizer. Because the catheter tip contains tungsten carbide, it has X-ray contrast properties. The catheter tip resin layer may be a single layer or multiple layers (two or more layers). In the case of multiple layers, the compositions (e.g., resin type and mixing ratio) may be different or the same. Furthermore, it is preferable that tungsten carbide is dispersed as particles within the resin.

[0046] The catheter tip may be composed of only the catheter tip resin layer, or may have other functional layers (for example, the aforementioned hydrophilic lubricating layer on the outer layer side) laminated on the inner layer side (lumen side) and / or outer layer side (surface side) of the catheter tip resin layer. The hydrophilic lubricating layer is as described above.

[0047] Examples of resins having an ester bond and / or an amide bond (hereinafter also simply referred to as resins having bonds) include polyamide, polyamide elastomer, polyamide imide, polyester, polyester elastomer, etc., and the above resins may be used alone or in the form of a laminate or blend of two or more types.

[0048] Among these, the resin having bonds preferably contains a polyamide-based resin because it has high flexibility and little affinity or difference in hardness with adjacent members, more preferably contains polyamide and / or polyamide elastomer (polyamide, polyamide elastomer, or a combination thereof), and even more preferably contains polyamide elastomer. The resin having bonds preferably contains 50% by mass or more (up to 100% by mass), more preferably 80% by mass or more (up to 100% by mass), and even more preferably 100% by mass (consisting of polyamide-based resin). Furthermore, the resin having bonds preferably contains 50% by mass or more (up to 100% by mass), more preferably 80% by mass or more (up to 100% by mass), and even more preferably 100% by mass (consisting of polyamide elastomer).

[0049] Among the resins constituting the catheter tip, the resin having bonds preferably accounts for 80% by mass or more (upper limit 100% by mass), more preferably 90% by mass or more (upper limit 100% by mass), and even more preferably 100% by mass (consisting of resin having bonds).Furthermore, among the resins in the catheter tip resin layer, the resin having bonds preferably accounts for 80% by mass or more (upper limit 100% by mass), more preferably 90% by mass or more (upper limit 100% by mass), and even more preferably 100% by mass (consisting of resin having bonds).

[0050] A polyamide elastomer that can be used as a resin having a bond is a thermoplastic resin made of a copolymer having hard segments derived from a crystalline polymer with a high melting point and soft segments derived from an amorphous polymer with a low glass transition temperature, and refers to a resin having an amide bond (-CONH-) in the main chain of the polymer that forms the hard segment. A structural unit having an amide bond (-CONH-) in the main chain of the polymer that forms the hard segment is also called an amide unit of a polyamide elastomer.

[0051] In this specification, the term "amide unit of a polyamide elastomer" refers to a repeating unit derived from an amide bond in a polymer chain of the polyamide elastomer, and the amide unit in the polyamide elastomer is preferably a repeating unit represented by the following formula (1):

[0052]

[0053] In the above formula (1), n ​​is preferably an integer of 2 to 20, and more preferably an integer of 5 to 11. In the examples described later, n is 11.

[0054] Examples of polymers that form soft segments include polyesters and polyethers. Further examples include polyethers such as polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol (PTMG), and polyester polyols, and ABA triblock polyether diols. The polymers that form soft segments may be used alone or in combination of two or more. Furthermore, polyether diamines obtained by reacting ammonia or the like with the terminals of polyethers may be used, and for example, ABA triblock polyether diamines may be used. Polyethers, which are polymers that can form soft segments, can form polyether block amide copolymers in which they are bonded to polyamide blocks, which are hard segments, via ester bonds.

[0055] The content of the soft segment in the polyamide elastomer is preferably from 1 to 50% by mass, more preferably from 10 to 30% by mass.

[0056] In addition to the hard segment and soft segment, the polyamide elastomer may contain a chain extender such as dicarboxylic acid.

[0057] These polyamide elastomers may be used alone or in combination of two or more.

[0058] The weight average molecular weight of the polyamide elastomer is preferably 10,000 to 500,000, more preferably 15,000 to 400,000, and even more preferably 20,000 to 300,000. In one embodiment, the weight average molecular weight of the polyamide elastomer is preferably 10,000 or more, more preferably 15,000 or more, and even more preferably 20,000 or more. In one embodiment, the weight average molecular weight of the polyamide elastomer is preferably 500,000 or less, more preferably 300,000 or less, and even more preferably 200,000 or less.

[0059] The molecular weight (e.g., number average molecular weight, weight average molecular weight, z-average molecular weight) of the polymer according to the present invention can be measured by a known method such as MS spectroscopy, light scattering, liquid chromatography, gas chromatography, or gel permeation chromatography (GPC), and in this specification, the molecular weight is measured by GPC.

[0060] The measurement conditions for the GPC method can be, for example, as follows: (1) Pretreatment: Filtration with a 0.45 μm PTFE cartridge filter (2) Apparatus: HLC-8420GPC (manufactured by Tosoh Corporation) (3) Separation column: TSKgel Super AWM-H (6.0 mm ID x 15 cm) (4) Measurement temperature: 40°C (5) Carrier: hexafluoroisopropanol (+10 mM CF ３ (COONa) (6) Flow rate: 0.3 mL / min (7) Injection volume: 20 μL (8) Detector: differential refractometer (RI detector), polarity = (+) (9) Concentration: 1 mg / mL (10) Molecular weight standard: standard polymethyl methacrylate.

[0061] From the viewpoint of flexibility, the Shore D hardness of polyamide elastomers that can be used in catheter tips is preferably 20 to 80, and more preferably 30 to 50. In this specification, the Shore D hardness according to ISO 868:2003 is used to measure the hardness of resins, such as polyamide elastomers. When multiple types of polyamide elastomers are used in this specification, the Shore D hardness of the entire polyamide elastomers is used, taking into account the mass ratio of the polyamide elastomers contained therein.

[0062] Polyamides that can be used as the bond-containing resin are not particularly limited as long as they are polymers having an amide bond (—CO—NH—) in the main chain, and are usually produced by polymerization of a lactam or amino acid with a ring structure, or by condensation polymerization of a dicarboxylic acid and a diamine. Homopolyamides are preferably used as polyamides. Monomers that can be polymerized independently include ε-caprolactam, ω-laurolactam, 6-aminocaproic acid, enantholactam, 7-aminoheptanoic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, 9-aminononanoic acid, and piperidone.

[0063] Furthermore, when polycondensing a dicarboxylic acid and a diamine, examples of the dicarboxylic acid include adipic acid, sebacic acid, dodecanedicarboxylic acid, glutaric acid, terephthalic acid, 2-methylterephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, etc. Examples of the diamine include tetramethylenediamine, hexamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, paraphenylenediamine, metaphenylenediamine, etc.

[0064] Examples of polyamides include nylon 4, 6, 7, 8, 11, 12, 6.6, 6.9, 6.10, 6.11, 6.12, 6T, 6 / 6.6, 6 / 12, 6 / 6T, 6T / 6I, etc. The polyamides may be used singly or in combination of two or more.

[0065] The polyamide may be end-capped with a carboxylic acid, an amine, etc. Examples of the carboxylic acid include aliphatic monocarboxylic acids such as caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, and behenic acid. Examples of the amine include aliphatic primary amines such as hexylamine, octylamine, decylamine, laurylamine, myristylamine, palmitylamine, stearylamine, and behenylamine.

[0066] The weight average molecular weight of the polyamide is preferably 10,000 to 500,000, more preferably 15,000 to 400,000, and even more preferably 20,000 to 300,000.

[0067] The resin content in the catheter tip resin layer is appropriately set taking into consideration X-ray contrast properties, flexibility, moldability, etc., and may be, for example, 10 to 40% by mass, or 20 to 35% by mass. In one embodiment, the resin content in the catheter tip resin layer is preferably 10% by mass or more, and more preferably 20% by mass or more. In one embodiment, the resin content in the catheter tip resin layer is preferably 40% by mass or less, and more preferably 35% by mass or less. In this specification, when the catheter tip resin layer is composed of multiple layers, the content of a certain component in the catheter tip resin layer means the ratio of the total mass of the certain component contained in all of the catheter tip resin layers to the total mass of all of the catheter tip resin layers.

[0068] The catheter tip resin layer also contains tungsten carbide as a radiopaque material. Metallic tungsten powder, which is commonly used as a radiopaque material, can release acid when oxidized and then hydrated, as described above. However, tungsten carbide is substantially immune to this effect, and as a result, the risk of resin decomposition is reduced, making it superior.

[0069] In one embodiment, only tungsten carbide is used as the radiopaque material. In one embodiment, the catheter tip resin layer contains simple metallic tungsten (W) powder as the radiopaque material. In one embodiment, the catheter tip resin layer does not contain simple metallic tungsten (W). In one embodiment, the catheter tip contains simple metallic tungsten (W) powder as the radiopaque material. In one embodiment, the catheter tip does not contain simple metallic tungsten (W). As used herein, the term "not containing" means, for example, that it is not intentionally added as a raw material, and also includes cases where it is contained due to unintentional contamination, for example, decomposition over time. Specifically, the content of metallic tungsten (W) powder in the catheter tip resin layer is preferably 0.01% by mass or less (lower limit: 0% by mass), and more preferably 0.001% by mass or less.

[0070] The particle size of the tungsten carbide can be 1 to 10 μm. When the particle size of the tungsten carbide is 1 μm or more, the surface area is sufficiently small, reducing the area exposed to air, making it difficult for the decomposition, oxidation, and hydration reactions of the tungsten carbide to proceed, and as a result, acid release is sufficiently suppressed. Furthermore, when the particle size of the tungsten carbide is 10 μm or less, the system is more likely to become uniform when mixed with the resin, contributing to improved operability during manufacturing and maintaining high quality of the catheter tip resin layer. The particle size of the tungsten carbide is preferably 2 to 5 μm, more preferably 3 to 4.5 μm. In one embodiment, the particle size of the tungsten carbide is 1 μm or more, preferably 2 μm or more, and more preferably 3 μm or more. In one embodiment, the particle size of the tungsten carbide is 10 μm or less, preferably 5 μm or less, and more preferably 4.5 μm or less.

[0071] Here, in this specification, particle size or particle diameter refers to the volume average particle diameter, which can be measured by, for example, but not limited to, a dynamic light scattering method.

[0072] Furthermore, various types of tungsten carbide are commercially available, and in the present invention, these commercially available products can be preferably used.

[0073] The tungsten carbide content may be 60% by mass or more relative to the entire catheter tip resin layer. When the tungsten carbide content is 60% by mass or more relative to the entire catheter tip resin layer, sufficient visibility of the catheter tip 20 can be ensured during X-ray transmission. In one embodiment, the tungsten carbide content is preferably 60 to 80% by mass, more preferably 65 to 80% by mass, and even more preferably 70 to 80% by mass, relative to the entire catheter tip resin layer, but a content of 60 to 70% by mass may also be suitable. In one embodiment, the tungsten carbide content may be 65% by mass or more, or 70% by mass or more, relative to the entire catheter tip resin layer. In another embodiment, the tungsten carbide content may be 80% by mass or less, or 70% by mass or less, relative to the entire catheter tip resin layer.

[0074] In the present invention, the catheter tip resin layer 21 may contain an additive. The additives that may be contained in the catheter tip resin layer 21 are not particularly limited, but include antioxidants and light stabilizers (in this specification, at least one additive selected from the group consisting of antioxidants and light stabilizers that may be contained in the catheter tip resin layer is referred to as a "first additive").

[0075] The antioxidant used herein can prevent deterioration such as denaturation and decomposition caused by oxidation of the resin. Examples of the antioxidant used herein include phosphorus-based antioxidants, sulfur-based antioxidants, and phenol-based antioxidants. Specific examples of phosphorus-based antioxidants include tris(nonylphenyl)phosphite, tris(2,4-di-t-butylphenyl)phosphite, distearyl pentaerythritol diphosphite, bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, bis(2,4-di-t-butyl-6-methylphenyl)pentaerythritol diphosphite, bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite, bis(2,4-dicumylphenyl)pentaerythritol diphosphite, tetrakis(2,4-di-t-butylphenyl)-4,4'-diphenylene diphosphonite, and 2,2'-methylenebis(4,6-di-t-butylphenyl). 2-ethylhexyl phosphite, 2,2'-ethylidenebis(4,6-di-t-butylphenyl)fluorophosphite, bis(2,4-di-t-butyl-6-methylphenyl)ethyl phosphite, 2-(2,4,6-tri-t-butylphenyl)-5-ethyl-5-butyl-1,3,2-oxaphosphorinane, 2,2',2''-nitrilotriethyl-tris(3,3',5,5'-tetra-t-butyl-1,1'-biphenyl-2,2'-diyl)phosphite, 2,4,8,10-tetra-t-butyl-6-[3-(3-methyl-4-hydroxy-5-t-butylphenyl)propoxy]dibenzo[d,f][1,3,2]dioxaphosphepine, and the like. Specific examples of sulfur-based antioxidants include dilauryl-3,3'-thiopropionate, dimyristyl-3,3'-thiodipropionate, disteary-3,3'-thiodipropionate, pentaerythritol tetrakis(3-laurylthiopropionate), ditridecyl-3,3'-thiodipropionate, 1,3,5-tris-β-stearylthiopropionyloxyethyl isocyanurate, and the like, but are not limited to these.Specific examples of the phenolic antioxidant include 2,6-di-t-butyl-4-methylphenol, octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 4,4'-butylidenebis(3-methyl-6-t-butylphenol), ethylenebis(oxyethylene)bis[3-(5-t-butyl-4-hydroxy-m-tolyl)propionate], 4,4'-thiobis(3-methyl-6-t-butylphenol), 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxyphenyl)propionate, Examples of antioxidants include, but are not limited to, tris-(3,5-di-t-butyl-4-hydroxybenzyl)benzene, 1,3,5-tris(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate, 3,9-bis-{2-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl}-2,4,8,10-tetraoxaspiro[5.5]undecane, tris-(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate, 2,2'-methylenebis(4-methyl-6-cyclohexylphenol), 2,2'-dihydroxy-3,3'-di(α-methylcyclohexyl)-5,5'-dimethyldiphenylmethane, and the like. These antioxidants may be used alone or in combination of two or more.

[0076] In this specification, the light stabilizer absorbs light of a corresponding wavelength, thereby preventing deterioration such as modification and decomposition caused by radical formation or other reactions resulting from the light absorption of the resin. Examples of the light stabilizer in this specification include, but are not limited to, ultraviolet absorbers and HALS (hindered amine light stabilizers).

[0077] Examples of the ultraviolet absorber include 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-[2-hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl]benzotriazole, 2-(2-hydroxy-3-t-butyl-5-methylphenyl)-5-chlorobenzotriazole, 2-(2-hydroxy-3,5-di-t-butylphenyl)-5-chlorobenzotriazole, 2-(2-hydroxy-3,5-di-t-butylphenyl)benzotriazole, 2-(2-hydroxy-3,5-di-t-amylphenyl)benzotriazole, 2-(2-hydroxy-5-t-octylphenyl)benzotriazole, 2-(2-hydroxy-octoxyphenyl)benzotriazole, 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-(1,1,3, benzotriazole-based ultraviolet absorbers such as 2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl]-5-(octyloxy)phenol and 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-(hexyloxy)phenol; benzophenone-based ultraviolet absorbers such as 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,4-dihydroxybenzophenone and 2,2',4,4'-tetrahydroxybenzophenone; benzoate-based ultraviolet absorbers such as 2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate and n-hexadecyl-3,5-di-t-butyl-4-hydroxybenzoate, but are not limited to these.

[0078] Examples of HALS include bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate and methyl 1,2,2,6,6-pentamethyl-4-piperidylsebacate (mixture), bis(1,2,2,6,6-pentamethyl-4-piperidyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butylmalonate, bis(2,2,6,6-tetramethyl-4-piperidyl)decanedioate, methyl-1(octyloxy)-4-piperidyl)ester and reaction products of 1,1-dimethylethyl hydroperoxide with octane, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, ester mixtures of 2,2,6,6-tetramethyl-4-piperidinol and higher fatty acids, tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate, tetrakis(1,2,2,6,6-pentamethyl-4-piperidyl) Poly(2,2,6,6-tetramethyl-4-piperidyl)imino)-1,2,3,4-butanetetracarboxylate, polycondensate of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol, poly[{(6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl){(2,2,6,6-tetramethyl-4-piperidyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidyl)imino}}, dibutylamine-1,3,5-triazine Examples of suitable amines include, but are not limited to, a polycondensate of N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine and N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine, and N,N',N'',N'''-tetrakis-(4,6-bis-(butyl-(N-methyl-2,2,6,6-tetramethylpiperidin-4-yl)amino)-triazin-2-yl)-4,7-diazadecane-1,10-diamine.

[0079] These light stabilizers may be used alone or in combination of two or more.

[0080] The antioxidant in the first additive and the second additive described below is preferably at least one of a phosphorus-based antioxidant, a sulfur-based antioxidant, and a phenol-based antioxidant, and the light stabilizer is preferably at least one of an ultraviolet absorber and a HALS.

[0081] Furthermore, the first additive and the second additive described below are preferably at least one selected from the group consisting of phosphorus-based antioxidants, sulfur-based antioxidants, phenol-based antioxidants, ultraviolet absorbers, and HALS.

[0082] The total content of the antioxidant and light stabilizer (first additive) in the catheter tip resin layer relative to the entire catheter tip resin layer may be 0% to 3% by mass, and preferably 0% to less than 3% by mass. When the total content of the antioxidant and light stabilizer is within the above range, the antioxidant and light stabilizer can be prevented from floating to the surface of the resin. In one embodiment, the total content of the antioxidant and light stabilizer in the catheter tip resin layer relative to the entire catheter tip resin layer can be 3% by mass or less (lower limit: 0% by mass), less than 3% by mass, 1% by mass or less, 0.5% by mass or less, 0.1% by mass or less, 0.05% by mass or less, 0.02% by mass or less, or 0.01% by mass or less. Furthermore, the total content of at least one agent selected from the group consisting of phosphorus-based antioxidants, sulfur-based antioxidants, phenol-based antioxidants, ultraviolet absorbers, and HALS that may be contained in the catheter tip resin layer relative to the entire catheter tip resin layer may be 0% by mass to 3% by mass, 0% by mass or more but less than 3% by mass, 0% by mass or more but 1% by mass or less, 0% by mass or more but 0.5% by mass or more, 0% by mass or more but 0.1% by mass or more, 0% by mass or more but 0.05% by mass or more, 0% by mass or more but 0.02% by mass or less, or 0% by mass or more but 0.01% by mass or more.

[0083] The catheter tip resin layer may also contain additives other than antioxidants and light stabilizers. Such additives may impart advantageous physical properties to the catheter tip, such as ease of handling. Examples of other additives used herein include, but are not limited to, plasticizers, lubricants, surfactants, antistatic agents, fillers, diluents, coupling agents, colorants, flame retardants, and foaming agents.

[0084] Examples of the plasticizer include benzoate esters such as diethylene glycol dibenzoate, phthalate esters such as dibutyl phthalate (DBP), di-2-ethylhexyl phthalate (DOP), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), diundecyl phthalate (DUP), ditridecyl phthalate (DTDP), bis(2-ethylhexyl) terephthalate (DOTP), and bis(2-ethylhexyl) isophthalate (DOIP), di-2-ethylhexyl adipate (DOA), and bis(2-ethylhexyl) adipate (DOA). Aliphatic dibasic acid esters such as diisononyl adipate (DINA), diisodecyl adipate (DIDA), di-2-ethylhexyl sebacate (DOS), diisononyl sebacate (DINS), etc.; trimellitic acid esters such as tri-2-ethylhexyl trimellitate (TOTM), triisononyl trimellitate (TINTM), triisodecyl trimellitate (TIDTM), etc.; pyromellitic acid esters such as tetra-2-ethylhexyl pyromellitate (TOPM), etc.; tri-2-ethylhexyl phosphate (TOP ), phosphate esters such as tricresyl phosphate (TCP), alkyl esters of polyhydric alcohols such as pentaerythritol, epoxidized vegetable oils such as epoxidized soybean oil and epoxidized linseed oil, epoxy esters such as 4,5-epoxy-1,2-cyclohexanedicarboxylic acid di-2-ethylhexyl ester, alicyclic dibasic acid esters such as 1,2-cyclohexanedicarboxylic acid diisononyl (DINCH) and 4-cyclohexene-1,2-dicarboxylic acid di-2-ethylhexyl ester, 1,4-butadipic acid dicaprate, Examples of the chlorinated fatty acid ester include, but are not limited to, fatty acid glycol esters such as phenylalanine diol, citric acid esters such as acetyl tributyl citrates (ATBC), acetyl trihexyl citrate (ATHC), acetyl triethylhexyl citrate (ATEHC), and butyryl trihexyl citrate (BTHC), isosorbide diesters, chlorinated paraffins obtained by chlorinating paraffin wax or n-paraffin, chlorinated fatty acid esters such as chlorinated stearic acid esters, and higher fatty acid esters such as butyl oleate.

[0085] Examples of lubricants include, but are not limited to, silicone, liquid paraffin, paraffin wax, metal salts of fatty acids such as metal stearates and metal laurates, fatty acid amides, fatty acid waxes, and higher fatty acid waxes.

[0086] Examples of surfactants include, but are not limited to, fatty acid esters of glycerin such as glycerin monostearate, glycerin monolaurate, glycerin monooleate, and glycerin monopalmitate; fatty acid esters of propylene glycol such as propylene glycol monolaurate, propylene glycol monostearate, propylene glycol monooleate, and propylene glycol monopalmitate; and fatty acid esters of sorbitan such as sorbitan monolaurate, sorbitan monostearate, sorbitan monooleate, and sorbitan monolpalmitate.

[0087] Examples of the antistatic agent include, but are not limited to, anionic antistatic agents of the alkyl sulfonate type, alkyl ether carboxylic acid type, or dialkyl sulfosuccinate type; nonionic antistatic agents such as polyethylene glycol derivatives, sorbitan derivatives, and diethanolamine derivatives; cationic antistatic agents such as quaternary ammonium salts of the alkyl amidoamine type and alkyl dimethyl benzyl type, and organic acid salts or hydrochlorides of alkyl pyridinium type; and amphoteric antistatic agents such as alkyl betaine type and alkyl imidazoline type.

[0088] Examples of diluents include, but are not limited to, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate and low-boiling aliphatic and aromatic hydrocarbons.

[0089] Examples of fillers include, but are not limited to, calcium carbonate, silica, alumina, clay, talc, diatomaceous earth, metal oxides such as ferrite, fibers and powders of glass, carbon, metals, etc., glass spheres, graphite, aluminum hydroxide, barium sulfate, magnesium oxide, magnesium carbonate, magnesium silicate, and calcium silicate.

[0090] Examples of colorants include, but are not limited to, carbon black, lead sulfide, white carbon, titanium white, lithopone, safflower, antimony sulfide, chrome yellow, chrome green, phthalocyanine green, cobalt blue, phthalocyanine blue, molybdenum orange, and the like.

[0091] Examples of flame retardants include, but are not limited to, inorganic compounds such as aluminum hydroxide, antimony trioxide, magnesium hydroxide, and zinc borate; phosphorus compounds such as cresyl diphenyl phosphate, trischloroethyl phosphate, trischloropropyl phosphate, and trisdichloropropyl phosphate; and halogen compounds such as chlorinated paraffin.

[0092] Examples of the foaming agent include, but are not limited to, organic foaming agents such as azodicarbonamide and oxybisbenzenesulfonylhydrazide, and inorganic foaming agents such as sodium bicarbonate.

[0093] In addition to the catheter tip resin layer, the catheter tip may be provided with an inner layer (inner layer 11 in Fig. 2) so that when a device such as a treatment catheter or a guide wire is inserted into the lumen 10H, at least the portion that comes into contact with the device has low friction. The inner layer is as described above.

[0094] (Catheter Body) The catheter body 10 is formed of a flexible, hollow tubular member. A lumen 10H is formed in the catheter body 10 over the entire length of the catheter body 10. The lumen 10H opens at the distal end of the catheter tip 20.

[0095] In the configuration shown in FIG. 2 , the catheter main body 10 has an inner layer 11 disposed on the inner surface, a catheter main body resin layer (outer layer; in this specification, referred to as the “catheter main body resin layer” or “catheter main body resin layer”) 12 disposed on the outer periphery of the inner layer 11, a lubricating layer 14 disposed at least on the distal end side of the outer periphery of the catheter main body resin layer 12, and a metal reinforcement layer 13 disposed inside the catheter main body resin layer 12.

[0096] 2, the inner layer 11 and the hydrophilic lubricating layer 14 are arranged to extend to the tip of the catheter tip 20. Therefore, the inner layer 11 and the hydrophilic lubricating layer 14 are common to the inner layer and the hydrophilic lubricating layer in the catheter tip 20.

[0097] Examples of resins that can be used to form the catheter main body resin layer 12 include polyolefins such as polypropylene, ethylene-propylene copolymer, and ethylene-vinyl acetate copolymer; modified polyolefin resins; thermoplastic resins such as soft polyvinyl chloride; various elastomers such as polyurethane elastomer, polyamide elastomer, and polyester elastomer; and crystalline plastics such as polyamide, crystalline polyethylene, and crystalline polypropylene. The catheter main body resin layer may be a single layer or multiple layers consisting of two or more layers. In the case of multiple layers, the compositions (such as resin types and mixing ratios) may be the same or different.

[0098] Among these, the resin constituting the catheter body resin layer 12 is preferably polyamide and / or polyamide elastomer (polyamide, polyamide elastomer, or a combination thereof).

[0099] The polyamide that can be contained in the catheter body resin layer can be the polyamide described above in the section on the catheter tip resin layer.

[0100] The polyamide elastomer that can be contained in the catheter body resin layer can be the polyamide elastomer described above in the section on the catheter tip resin layer.

[0101] From the viewpoint of flexibility, the Shore D hardness of the polyamide elastomer used in the catheter main body is preferably 30 to 80 D, more preferably 40 to 75 D. The method for measuring the hardness of the polyamide elastomer is as described above. The Shore D hardness of the resin of the catheter main body is preferably equal to or greater than the Shore D hardness of the resin of the catheter tip, and more preferably greater.

[0102] In one embodiment, the resin content may be 20 to 99.9% by mass, more preferably 30 to 95% by mass, even more preferably 50 to 90% by mass, and even more preferably 70 to 90% by mass, of the entire catheter body resin layer. When the resin content is within the above range, the moldability of the catheter body can be maintained, and operability during insertion is particularly excellent. In this specification, when the catheter body resin layer is composed of multiple layers, the content of a certain component in the catheter body resin layer refers to the ratio of the total mass of a certain component contained in all of the catheter body resin layers to the total mass of all of the catheter body resin layers.

[0103] Tungsten carbide may or may not be included in the catheter body resin layer as a radiopaque substance to allow the position of the catheter body to be determined during X-ray irradiation. In one embodiment, the tungsten carbide content may be 1% by mass or more, 10% by mass or more, 30% by mass or more, or 60% by mass or more, based on the total mass of the catheter body resin layer. In another embodiment, the tungsten carbide content may be 79.9% by mass or less, 50% by mass or less, 20% by mass or less, 10% by mass or less, 5% by mass or less, or 1% by mass or less (lower limit: 0% by mass), based on the total mass of the catheter body resin layer.

[0104] In one embodiment, the amount of tungsten carbide that may be contained in the catheter body resin layer relative to the entire catheter body resin layer may be less than the amount of tungsten carbide that may be contained in the catheter tip resin layer relative to the entire catheter tip resin layer.

[0105] In one embodiment, the catheter body resin layer contains a simple metallic tungsten (W) powder as a radiopaque material to allow the position of the catheter body to be determined during X-ray irradiation. The content of the simple metallic tungsten powder is, for example, more than 0.01% by mass and less than 10% by mass, or may be 0.1% by mass or more and 1% by mass or less, relative to the entire catheter body resin. In one embodiment, the catheter body resin layer does not contain simple metallic tungsten (W).

[0106] The catheter body also contains at least one of an antioxidant and a light stabilizer (referred to herein as a "second additive") to prevent deterioration of the resin. In one embodiment, at least one of an antioxidant and a light stabilizer may be contained in the catheter body resin layer. The antioxidants and light stabilizers that may be contained in the catheter body resin layer are as described above. Here, the second additive may be the same type as the first additive or may be a different type.

[0107] In one embodiment, the total content of the antioxidant and light stabilizer contained in the catheter body resin layer relative to the entire catheter body resin layer is preferably 0.1 to 10% by mass, more preferably 0.1 to 3% by mass, even more preferably 0.1 to 1% by mass, and still more preferably 0.1 to 0.5% by mass. In one embodiment, the total content of the antioxidant and light stabilizer contained in the catheter body resin layer relative to the entire catheter body resin layer is 0.1% by mass or more, 0.15% by mass or more, 0.2% by mass or more, 0.3% by mass or more, 0.5% by mass or more, 1% by mass or more, 2.0% by mass or more, or 3% by mass or more. In one embodiment, the total content of the antioxidant and the light stabilizer in the resin layer of the catheter body relative to the entire resin layer of the catheter body may be 10% by mass or less, 5% by mass or less, 3% by mass or less, 1% by mass or less, 0.5% by mass or less, 0.2% by mass or less, 0.15% by mass or less, 0.11% by mass or less, or 0.1% by mass or less.

[0108] Furthermore, the total content of at least one selected from the group consisting of phosphorus-based antioxidants, sulfur-based antioxidants, phenol-based antioxidants, ultraviolet absorbers, and HALS, which may be contained in the resin layer of the catheter body, relative to the total content of the resin layer of the catheter body, is preferably 0.1 to 10% by mass, more preferably 0.1 to 3% by mass, even more preferably 0.1 to 1% by mass, and still more preferably 0.15 to 0.5% by mass.

[0109] The total content of the antioxidant and light stabilizer (first additive) in the catheter tip resin layer may be less than the total content of the antioxidant and light stabilizer (second additive) in the catheter body resin layer as a whole. In one embodiment, the total content of the antioxidant and light stabilizer in the catheter tip resin layer is preferably ½ or less, more preferably ⅓ or less, and even more preferably 1 / 10 or less, of the total content of the antioxidant and light stabilizer in the entire catheter body resin layer. For example, the total content of the antioxidant and light stabilizer in the catheter tip resin layer is 0% by mass, and the total content of the antioxidant and light stabilizer in the catheter body resin layer is 0.1% by mass or more. As an example, the total content of the antioxidant and light stabilizer in the catheter tip resin layer relative to the catheter tip resin layer is 0% by mass, and the total content of the antioxidant and light stabilizer in the catheter main body resin layer relative to the entire catheter main body resin layer is 0.1% by mass.

[0110] The catheter body resin layer may also contain additives other than the antioxidant and light stabilizer, as described above.

[0111] The catheter main body 10 further includes a metal reinforcing layer 13. The metal reinforcing layer 13 has a plurality of reinforcing wires that reinforce the catheter main body 10. Examples of the reinforcing wires include those in a spiral or braided shape. The reinforcing wires are made of a metal such as stainless steel. Specific examples include a structure in which stainless steel wires are flattened into a plate shape and then multiple wires, approximately 8 to 32 in number, are used to form a spiral or braided structure (braided structure) so as to reduce the radial thickness of the catheter main body 10. The number of reinforcing wires is preferably a multiple of 8 to achieve balanced reinforcement in a tubular shape, but is not limited to this.

[0112] By making the reinforcing wire flat, it receives external stress evenly compared to an ellipse, resulting in consistent physical properties.

[0113] The catheter body 10 may also include an inner layer 11 and a hydrophilic lubricating layer 14. The inner layer 11 and the hydrophilic lubricating layer 14 are as described above.

[0114] The number of layers constituting the catheter main body 10 and the materials constituting each layer may vary along the longitudinal direction of the catheter main body 10. For example, the distal end portion of the catheter main body 10 may have fewer layers or may be made of a more flexible material in order to provide greater flexibility.

[0115] In this specification, the term "catheter main body" refers to a portion having a metal reinforcing layer 13 at any radial position, and the term "catheter tip" refers to the entire portion distal to the catheter main body. The distal end of the catheter main body 10 and the catheter tip 20 can be joined together by, for example, heat fusion to form an integrated unit.

[0116] The effects of the present invention will be explained using the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following examples. In the following examples, unless otherwise specified, each operation was carried out at room temperature (25°C). Furthermore, unless otherwise specified, "%" or "parts" means "% by mass" or "parts by mass".

[0117] [Preparation of dumbbell-shaped test pieces] [Example 1] 30 parts by mass of polyamide elastomer (Shore D hardness 40, weight-average molecular weight (Mw) approximately 40,000) was mixed with 70 parts by mass (mass ratio) of tungsten carbide particles (average particle diameter 3.0 to 4.19 μm). The obtained resin was press-molded using a 20 ton manual hydraulic heating press at a set temperature of 200°C. The thickness of the molded product was 1.9 to 2.1 mm. The molded press sheet was punched out according to JIS K 7161-2:2014 5A to prepare dumbbell-shaped test pieces.

[0118] Comparative Example 1 A dumbbell-shaped test piece was prepared in the same manner as in Example 1, except that tungsten particles (average particle size 3.0 μm, W content 99.9% by mass or more) were used instead of tungsten carbide particles.

[0119] [Load Test] The dumbbell-shaped test pieces prepared in the Examples and Comparative Examples were subjected to high temperature and high humidity conditions. Specifically, the dumbbell-shaped test pieces were subjected to a load test for a total of four cycles (96 hours), with the conditions shown in Table 2 below being defined as one cycle (24 hours).

[0120]

[0121] [Tensile Test] According to JIS K 7161-1:2014, a tensile test was performed on the dumbbell-shaped test pieces of Example 1 and Comparative Example 1 before and after the load test.

[0122] <Test conditions> Distance between grippers: 50 mm Distance between gauge lines: 20 mm Test speed: 100 mm / min The survival rate was calculated using the following formula to indicate durability. A higher survival rate indicates higher durability. Here, the breaking stroke length refers to the value obtained by subtracting the gauge line distance before the test from the gauge line distance after breaking.

[0123]

[0124]

[0125] As a result of the tensile test, the dumbbell-shaped test specimen of Comparative Example 1 had a survival rate of 15.8% before and after the load test, whereas the dumbbell-shaped test specimen of Example 1 had a survival rate of 89.4% before and after the load test, which was higher than that of Comparative Example 1. This result confirmed that the dumbbell-shaped test specimen of Example 1 had higher durability than the dumbbell-shaped test specimen of Comparative Example 1, even though it did not contain at least one first additive selected from the group consisting of antioxidants and light stabilizers.

[0126] This application is based on Japanese Patent Application No. 2023-102507, filed on June 22, 2023, the disclosure of which is incorporated by reference in its entirety.

[0127] 1 Catheter, 10 Catheter body, 30 Hub, 20 Catheter tip, 40 Kink-resistant protector (strain relief).

Claims

1. A catheter tip having a catheter tip resin layer containing 60% by mass or more of tungsten carbide (WC), A catheter body having a catheter body resin layer containing at least one second additive selected from the group consisting of antioxidants and light stabilizers, Includes, The particle size of the tungsten carbide is 1 to 10 μm. If the catheter body resin layer contains tungsten carbide, the amount of tungsten carbide contained in the catheter body resin layer relative to the entire catheter body resin layer is less than the amount of tungsten carbide contained in the catheter tip resin layer relative to the entire catheter tip resin layer. The total amount of at least one first additive selected from the group consisting of antioxidants and light stabilizers contained in the catheter tip resin layer is less than the total amount of the second additive contained in the catheter body resin layer. The total content of the first additive is 0% by mass or more and 0.1% by mass or less relative to the catheter tip resin layer. catheter.

2. The catheter according to claim 1, wherein the resin contained in the catheter tip resin layer is a resin having ester bonds and / or amide bonds.

3. The catheter according to claim 2, wherein the resin having ester bonds and / or amide bonds includes a polyamide resin.

4. The catheter according to claim 1 or 2, wherein the catheter tip does not contain tungsten (W) powder.

5. The antioxidant is at least one of phosphorus-based antioxidants, sulfur-based antioxidants, and phenol-based antioxidants. The catheter according to claim 1 or 2, wherein the light stabilizer is at least one of an ultraviolet absorber and HALS.