Flexible tube for endoscope, endoscope-type medical instrument, and flexible tube base material for endoscope

Abstract

This invention provides a flexible tube for endoscopes, an endoscopic medical device having the flexible tube, and a coating material for the flexible tube substrate. The flexible tube comprises a flexible cylindrical flexible tube substrate and a coating layer of the flexible tube substrate. The coating layer contains at least one of (a) (a1) a polyester resin having a naphthalene structure and (a2) a polyester elastomer having a naphthalene structure, and at least one of (b) (b1) a thermoplastic resin without a naphthalene structure and (b2) a thermoplastic elastomer without a naphthalene structure. Component (a) accounts for more than 50% by mass and less than 90% by mass of the total amount of components (a) and (b) in the coating layer.

Description

Technical Field

[0001] This invention relates to flexible tubes for endoscopes, endoscopic medical devices, and coating materials for flexible tube substrates for endoscopes. Background Technology

[0002] An endoscope is a medical instrument used to observe the inside of a patient's body cavities, digestive tract, or esophagus. Because it is inserted into the body, it is desirable to avoid damaging organs and to minimize pain and discomfort for the patient. Considering these requirements, the flexible tube constituting the insertion part of the endoscope is a spiral tube formed by spirally winding a soft, bent metal strip. Furthermore, it is surrounded by a soft polymer material to prevent irritation or damage to the inner surfaces of the esophagus, digestive tract, or body cavities.

[0003] Endoscopes used for observing the human body are reused. Therefore, the flexible tube that forms the insertion part of the endoscope needs to be cleaned and sterilized with chemicals after each use. Especially when inserted into high-risk sites such as the bronchus, a level of cleanliness exceeding that of sterilization is required. Therefore, the flexible tube for endoscopes must possess a high degree of durability that can withstand repeated sterilization processes.

[0004] For example, Patent Document 1 describes a flexible tube for endoscopes, which is formed by covering the surface of the flexible tube material with an outer skin. The outer skin is made of a polyester elastomer in which polybutylene naphthalene is used in the hard segments, which improves the heat resistance and hydrolysis resistance of the outer skin and can be used in an autoclave (high-pressure steam sterilization).

[0005] In addition, Patent Document 2 describes an endoscope flexible tube covered with an outer skin made of an endoscope elastomer molded body made of two or more thermoplastic polyester elastomers, which is less prone to outer skin deterioration for various drugs.

[0006] Previous technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2004-141487

[0009] Patent Document 2: Japanese Patent Application Publication No. 2009-183467 Summary of the Invention

[0010] The technical problem to be solved by the invention

[0011] As a sterilization process for flexible endoscope tubes, autoclave treatment as described above is performed. In addition, in recent years, from the viewpoint of suppressing the deterioration of flexible endoscope tubes due to damp heat, chemical sterilization treatments using hydrogen peroxide plasma, ethylene oxide gas, etc., have been widely implemented. Furthermore, sterilization treatment using ozonated water, prepared by dissolving trace amounts of ozone (O3) in water, has recently begun. This ozonated water generates highly reactive species such as hydroxyl radicals, and its oxidizing power is stronger than that of hydrogen peroxide gas. Therefore, as an organic material resistant to ozonated water sterilization treatment, fluoropolymers are currently in the known stage.

[0012] Furthermore, even without autoclaving, the flexible tubes used in endoscopes require moisture and heat resistance. This means that the flexible tube portion of the endoscope is inserted into the body, and the target internal area is observed and lesions treated while being illuminated by strong light. These observations and treatments under strong light are performed while rinsing the observation window (lens) of the flexible tube with water. In other words, the endoscope, after insertion, is exposed to heat and moisture from the light source, placing it in a moisture and heat environment. Therefore, during repeated in vivo observations or lesion treatments, the coating (outer skin) of the flexible tube deteriorates, and water vapor easily penetrates the interior of the flexible tube, accelerating the deterioration of various components that make up the endoscope. Recently, there has been an increasing demand for smaller diameter flexible tubes for endoscopes, and the coating is being made thinner, leading to higher requirements for the moisture and heat resistance (water vapor barrier properties) of the coating.

[0013] In view of the above, the object of the present invention is to provide an endoscope flexible tube that exhibits excellent gas barrier properties even when exposed to a humid and hot environment for a long time, and excellent sterilization durability against powerful sterilization treatments such as ozone water, and an endoscope-type medical device using the same. Furthermore, another object of the present invention is to provide an endoscope flexible tube substrate coating material suitable for forming the coating layer of the aforementioned endoscope flexible tube.

[0014] means for solving technical problems

[0015] The inventors, through repeated and dedicated research into the aforementioned issues, discovered that by using a polymer blend comprising a polyester resin or polyester elastomer having a naphthalene structure and a thermoplastic resin or thermoplastic elastomer without a naphthalene structure in a specific ratio as the constituent material of the coating layer of a flexible tube for endoscopes, the resulting coating layer, while the polymers are separated from each other, forms a homogeneous composition. This coating layer, as a thin layer, exhibits excellent gas barrier properties even under prolonged exposure to humid and hot environments, and possesses durability that is not easily degraded even under intensive sterilization treatments such as ozone water. This invention was completed based on further repeated research based on these insights.

[0016] The above objectives can be achieved through the following methods.

[0017] <1>

[0018] A flexible tube comprising a flexible cylindrical flexible tube substrate and a coating layer thereof, wherein,

[0019] The aforementioned coating layer contains components (a) and (b), wherein component (a) accounts for more than 50% by mass and less than 90% by mass of the total amount of components (a) and (b) in the aforementioned coating layer.

[0020] (a) (a1) at least one of a polyester resin having a naphthalene structure and (a2) a polyester elastomer having a naphthalene structure;

[0021] (b)(b1) at least one of a thermoplastic resin that does not have a naphthalene structure and (b2) a thermoplastic elastomer that does not have a naphthalene structure.

[0022] <2>

[0023] according to <1> The flexible tube for the endoscope, wherein,

[0024] The thermoplastic resins that do not have a naphthalene structure as described above (b1) include at least one of polyolefin resins, polydiene resins, polystyrene resins, polyacrylic resins, polyvinyl resins, polyester resins, polyamide resins, polycarbonate resins, polyurethane resins, polysulfone resins, polyether resins, and fluorinated resins.

[0025] <3>

[0026] according to <2> The flexible tube for the endoscope, wherein,

[0027] The thermoplastic resins that do not have a naphthalene structure, as described in (b1), include at least one of polyolefin resins, polydiene resins, and polystyrene resins.

[0028] <4>

[0029] according to <1> ~ <3> The flexible tube for the endoscope described in any one of the following statements, wherein,

[0030] The thermoplastic elastomers that do not have a naphthalene structure as described in (b2) above include at least one of polystyrene elastomers, polyolefin elastomers, polyvinyl chloride elastomers, polyurethane elastomers, polyester elastomers, and polyamide elastomers.

[0031] <5>

[0032] according to <4> The flexible tube for the endoscope, wherein,

[0033] The thermoplastic elastomers that do not have a naphthalene structure as described in (b2) above include at least one of polystyrene elastomers and polyolefin elastomers.

[0034] <6>

[0035] according to <1> ~ <5> The flexible tube for the endoscope described in any one of the following statements, wherein,

[0036] In the aforementioned coating layer, the aforementioned component (a) and the aforementioned component (b) are separated from each other.

[0037] <7>

[0038] according to <1> ~ <6> The flexible tube for the endoscope described in any one of the following statements, wherein,

[0039] The aforementioned coating contains a compatibilizer.

[0040] <8>

[0041] An endoscopic medical device, which has <1> ~ <7> The flexible tube for endoscopes as described in any one of the above.

[0042] <9>

[0043] A flexible tube substrate coating material for endoscopes contains components (a) and (b), wherein component (a) constitutes more than 50% by mass and less than 90% by mass of the total amount of components (a) and (b).

[0044] (a) (a1) at least one of a polyester resin having a naphthalene structure and (a2) a polyester elastomer having a naphthalene structure;

[0045] (b)(b1) at least one of a thermoplastic resin that does not have a naphthalene structure and (b2) a thermoplastic elastomer that does not have a naphthalene structure.

[0046] Invention Effects

[0047] The flexible endoscope tube of the present invention exhibits excellent gas barrier properties even when exposed to humid and hot environments for extended periods, and demonstrates excellent sterilization durability against potent sterilization treatments such as ozone water. The endoscopic medical device of the present invention is an instrument incorporating the aforementioned excellent properties of the flexible endoscope tube. Furthermore, the coating material of the present invention is suitable as a polymer material constituting the coating layer of the flexible endoscope tube of the present invention. Attached Figure Description

[0048] Figure 1 This is an external diagram showing the structure of an electronic endoscope.

[0049] Figure 2 This is a partial cross-sectional view showing the general structure of the flexible tube used for endoscopy. Detailed Implementation

[0050] A preferred embodiment of the endoscopic medical device of the present invention will be described using an electronic endoscope as an example. The electronic endoscope is equipped with an endoscopic flexible tube (hereinafter, the endoscopic flexible tube will also be simply referred to as "flexible tube"), and is widely used as a medical device. Figure 1 In the example shown, the electronic endoscope 2 includes an insertion part 3 inserted into the body, a main operating part 5 connected to the base of the insertion part 3, and a universal plug 6 connected to a processor or light source device. The insertion part 3 consists of a flexible tube 3a connected to the main operating part 5, a bend 3b connected to the flexible tube 3a, and a tip part 3c connected to the front end of the bend 3b and housing an in-body imaging device (not shown). The flexible tube 3a, which occupies most of the length of the insertion part 3, is flexible almost along its entire length, and the portion inserted into the body is particularly flexible.

[0051] Flexible tube

[0052] like Figure 2 As shown, the flexible tube 3a (flexible tube for endoscope) is configured to have a flexible tube substrate 14, which is formed by winding a metal strip 11a into a spiral shape on the innermost side, covered with a cylindrical mesh 12 made of woven metal wire, and fitted with tube heads 13 at both ends. Furthermore, a coating layer 15 is applied to the outer peripheral surface of the flexible tube substrate 14. Only one layer of the spiral tube 11 is shown, but it can also be configured as two coaxially overlapping layers. Moreover, to clearly illustrate the layer structure, the coating layer 15 is depicted as being thicker than the wall of the flexible tube substrate 14.

[0053] In this embodiment, the coating layer 15 is formed with a substantially uniform thickness along the longitudinal direction (axial direction) of the flexible tube substrate 14. The thickness of the coating layer 15 is, for example, 0.1 to 0.6 mm, and the outer diameter D of the flexible tube 3a is, for example, 2.0 to 10.0 mm, preferably 3.0 to 8.0 mm. Furthermore, the outer diameter of the flexible tube substrate 14 is, for example, 1.6 to 9.6 mm, preferably 2.2 to 7.8 mm. When the insertion part 3 is inserted into the bronchus, the thickness of the coating layer 15 is preferably 0.1 to 0.3 mm, the outer diameter D of the flexible tube 3a is preferably 3.0 to 5.0 mm, and the outer diameter of the flexible tube substrate 14 is preferably 2.4 to 4.8 mm.

[0054] The flexible tube for endoscopes of the present invention comprises a flexible cylindrical flexible tube substrate and a coating layer covering the flexible tube substrate, wherein the coating layer contains the following components (a) and (b).

[0055] (a) (a1) at least one of a polyester resin having a naphthalene structure and (a2) a polyester elastomer having a naphthalene structure;

[0056] (b)(b1) at least one of a thermoplastic resin that does not have a naphthalene structure and (b2) a thermoplastic elastomer that does not have a naphthalene structure.

[0057] In this invention, the proportion of the above-mentioned component (a) to the total amount of the above-mentioned components (a) and (b) in the above-mentioned coating layer is more than 50% by mass and less than 90% by mass.

[0058] In the flexible endoscope tube of the present invention, component (a) constituting the coating layer has a naphthalene structure, exhibiting strong intramolecular and intermolecular interactions. Therefore, when components (a) and (b) are uniformly blended in a prescribed ratio, the two components are not easily immiscible, resulting in a phase-separated state at the microscopic level. For example, a phase-separated state is formed where component (a) is the continuous phase and component (b) is the dispersed phase. It can be assumed that when such a phase-separated state is formed, the phases repel each other, resulting in a strong aggregation of polymer blocks in each phase. As a result, it can be inferred that the water vapor barrier is improved, and the ozone water resistance is also effectively improved. Furthermore, it can be inferred that the large molecular area unique to naphthalene also contributes to this improvement in barrier performance. In addition, sometimes the distinction between the continuous and dispersed phases is not always clear, but the portion of component (a), which has a larger proportion of component (a) in the coating layer, tends to increase in its continuous (connected) presence throughout the entire coating layer. In addition, the particle size of each dispersed phase (the phase existing in the form of particles) is preferably about 1 to 50 μm when viewed from above, and is also preferably about 1 to 30 μm.

[0059] The aforementioned coating layer 15 can be a single layer or a multilayer composed of layers with different compositions (multilayers with different ratios of dicarboxylic acid components or diol components). The aforementioned coating layer 15 is preferably a single layer. When the aforementioned coating layer 15 is a multilayer, at least one layer is composed of the endoscope flexible tube substrate coating material of the present invention, and preferably the outermost layer is composed of the endoscope flexible tube substrate coating material of the present invention. Furthermore, the flexible tube of the present invention may have a surface coating on the outer side of the aforementioned coating layer. For example, the composition of the surface coating can be found in Japanese Patent Application Publication No. 2015-16261.

[0060] (Polyester with naphthalene structure [component (a)])

[0061] The above component (a) is at least one of (a1) a polyester resin having a naphthalene structure and (a2) a polyester elastomer having a naphthalene structure.

[0062] Preferably, the polyester resin of component (a1) and the polyester elastomer of component (a2) are composed of a dicarboxylic acid component and a diol component, which preferably contain a naphthalene dicarboxylic acid component.

[0063] In this invention, a specific example of a preferred dicarboxylic acid component as a naphthalenedicarboxylic acid component is 2,6-naphthalenedicarboxylic acid.

[0064] First, the polyester resin having a naphthalene structure in the above component (a1) will be described.

[0065] The polyester resin having a naphthalene structure as described above (a1) preferably has a naphthalene dicarboxylic acid component. Polyester resins having a naphthalene dicarboxylic acid component may also have a dicarboxylic acid component other than naphthalene dicarboxylic acid as the dicarboxylic acid component.

[0066] Other than naphthalene dicarboxylic acid, the aforementioned dicarboxylic acid components are not particularly restricted and can be widely used as dicarboxylic acid components commonly used to constitute polyester resins. Examples include terephthalic acid, isophthalic acid, phthalic acid, sodium isophthalate-5-sulfonate, oxalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, dodecanoic acid, dimer acid, maleic anhydride, maleic acid, fumaric acid, itaconic acid, citraconic acid, mesocarboxylic acid, cyclohexanedicarboxylic acid, etc. One or more of these dicarboxylic acid components can be used.

[0067] The polyester resin containing the naphthalene structure described above (a1) is widely used as a diol component commonly found in polyester resins. Examples include ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, cyclohexanediol, triethylene glycol, bisphenol A, and bisphenol S. One or more of these diol components may be used.

[0068] Polyester resins containing a naphthalene structure, as described above (a1), may also incorporate hydroxycarboxylic acid components. Examples of such hydroxycarboxylic acid components include ε-caprolactone, lactic acid, and 4-hydroxybenzoic acid. One or more of these hydroxycarboxylic acid components may be used.

[0069] The polyester resin with naphthalene structure in component (a1) can be a homopolymer or a copolymer composed of the above components, and may further contain small amounts of trifunctional compounds such as trimellitic acid, pyromellitic acid, pyromellitic tetracarboxylic acid, trimethylolpropane, glycerol, and pentaerythritol.

[0070] In addition, the polyester resin having a naphthalene structure as the above-mentioned component (a1) may also be used in combination with two or more homopolymers or copolymers composed of the above-mentioned components.

[0071] Next, the polyester elastomer having a naphthalene structure of the above component (a2) will be described.

[0072] The polyester elastomer having a naphthalene structure as described above (a2) preferably has a naphthalene dicarboxylic acid component. More preferably, it is a copolymer composed of hard segments and soft segments, wherein the hard segments are composed of crystalline polyester chains having a dicarboxylic acid component including a naphthalene dicarboxylic acid component and a low molecular weight diol component as constituent components, and the soft segments are at least any one of (i) to (iii) below.

[0073] (i) Soft segments composed of aliphatic polyester chains;

[0074] (ii) Soft segments composed of aliphatic polymer diol components;

[0075] (iii) A soft segment composed of a polyester chain, said polyester chain being composed of an aliphatic polymer diol component and a dicarboxylic acid component containing an aromatic dicarboxylic acid.

[0076] That is, the naphthalene structure can be introduced into either or both of the hard and soft segments, preferably into at least the hard segment.

[0077] The following describes polyester elastomers with naphthalene structures in their hard segments.

[0078] Polyester elastomers with a naphthalene structure in their hard segments preferably have naphthalene dicarboxylic acid components in their hard segments. When the hard segments have naphthalene dicarboxylic acid components, all dicarboxylic acid components in the hard segments can be naphthalene dicarboxylic acid components, and the hard segments may also contain dicarboxylic acid components other than naphthalene dicarboxylic acid components. As dicarboxylic acid components other than naphthalene dicarboxylic acid components constituting the hard segments, dicarboxylic acid components commonly used as components of hard segments constituting ordinary polyester elastomers can be widely used. Examples include, for instance, dicarboxylic acid components other than naphthalene dicarboxylic acid components described in the description of the polyester resin with a naphthalene structure described above; one or more of these dicarboxylic acid components may be present. Preferably, the dicarboxylic acid components other than naphthalene dicarboxylic acid components constituting the hard segments include aromatic dicarboxylic acid components (dicarboxylic acid components having aromatic rings), and preferably 50% by mass or more (preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more) of the dicarboxylic acid components other than naphthalene dicarboxylic acid components are aromatic dicarboxylic acid components. Furthermore, it is also preferable that all dicarboxylic acid components other than naphthalene dicarboxylic acid components constituting the hard segments are aromatic dicarboxylic acid components.

[0079] As the diol component constituting the aforementioned hard segment, a wide range of diol components commonly used as constituents of polyester resins can be applied. Examples include the diol components described in polyester resins having a naphthalene structure in component (a1) above, and one or more of these diol components may be present.

[0080] The aforementioned hard segment may contain one or more of the hydroxycarboxylic acid components described in the description of the polyester resin having a naphthalene structure in the aforementioned component (a1) as constituent components.

[0081] The aforementioned hard segments can be homopolymers composed of the constituent components described above, or they can be copolymers.

[0082] When the aforementioned soft segment is (i) an aliphatic polyester chain, the dicarboxylic acid component constituting the aliphatic polyester chain is not particularly limited as long as it is an aliphatic dicarboxylic acid component. It may contain components derived from, for example, oxalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, dodecanoic acid, dimer acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, mesocarboxylic acid, cyclohexanedicarboxylic acid, etc. The aliphatic polyester chain may contain one or more of these dicarboxylic acid components.

[0083] The diol component of the aliphatic polyester chain constituting the aforementioned soft segment is not particularly limited as long as it is an aliphatic diol. Examples of aliphatic diol components include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 3-methyl-1,5-pentanediol, 1,3-propanediol, 1,4-butanediol, 1,9-nonanediol, neopentanediol, 1,5-pentanediol, 1,6-hexanediol, decanediol, and cyclohexanediol. One or more of these diol components may be present. Furthermore, the aliphatic polyester chain preferably contains an aliphatic polymeric diol component. Examples of aliphatic polymeric diol components include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, and other polyalkylene glycols. One or more of these aliphatic polymeric diol components may be present. In this invention, the polyalkylene glycol is HO-[(CH2)] m O] n The compound represented by -H. Here, m is preferably 1 to 12, more preferably 2 to 10, even more preferably 2 to 8, and particularly preferably 2 to 6. In addition, n is preferably 5 to 100, more preferably 10 to 50.

[0084] Furthermore, in the case where the aforementioned soft segment is (ii) an amorphous soft segment derived from an aliphatic polymeric diol, the aliphatic polymeric diol is not particularly limited as long as it is an aliphatic polymeric diol. Examples include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, and other polyalkylene glycols. The polyester elastomer may be configured to have a structure having one or more of these aliphatic polymeric diol components as soft segments. The structure of polyalkylene glycols is as described above.

[0085] Furthermore, when the aforementioned soft segment is (iii) a soft segment composed of a polyester chain, wherein the polyester chain is composed of an aliphatic polymer diol component and a dicarboxylic acid component containing an aromatic dicarboxylic acid, the aliphatic polymer diol component is not particularly limited, and examples such as the components derived from aliphatic polymer diols described in (ii) above can be listed. Additionally, as an aromatic dicarboxylic acid component, components derived from naphthalene dicarboxylic acid can be listed. Furthermore, when a dicarboxylic acid component other than an aromatic dicarboxylic acid component is included, the dicarboxylic acid components described in (i) above can be listed as such dicarboxylic acid components.

[0086] Examples of the above-mentioned components (a) having a naphthalene structure that are commercially available include TQB-KET30 (manufactured by Teijin Chemical Co., Ltd.) and PELPRENE EN type (manufactured by Toyobo Co., Ltd.).

[0087] Polyesters with naphthalene structures can be used alone or in combination of two or more.

[0088] (Thermoplastic resins and thermoplastic elastomers without naphthalene structure [component (b)])

[0089] The aforementioned component (b) is at least one of (b1) a thermoplastic resin without a naphthalene structure and (b2) a thermoplastic elastomer without a naphthalene structure. The aforementioned component (b) is not particularly limited as long as it is a thermoplastic resin or thermoplastic elastomer without a naphthalene structure; however, a substance with a low number of polar functional groups and high hydrophobicity is preferred. It can be considered that by increasing the hydrophobicity of component (b), the interaction with the naphthalene structure of component (a) is enhanced, the barrier function as a coating layer between phases is further improved, and the permeability to water vapor under humid and hot conditions and the inhibition of the penetration of active species such as hydroxyl radicals generated by ozone water are enhanced.

[0090] The thermoplastic resin of the above component (b1) preferably includes at least one of polyolefin resin, polydiene resin, polystyrene resin, polyacrylic resin, polyvinyl resin, polyester resin, polyamide resin, polycarbonate resin, polyurethane resin, polysulfone resin, polyether resin and fluorinated resin.

[0091] The thermoplastic resin of the above component (b1) more preferably includes at least one of polyolefin resin, polydiene resin and polystyrene resin.

[0092] <Polyolefin resin>

[0093] In this invention, the term "polyolefin resin" refers to a resin composed of a polymer containing an olefin component. The polymer containing the olefin component can be an olefin homopolymer or an olefin copolymer. Examples of olefin copolymers include copolymers of a certain olefin and olefins different from it, and copolymers of olefins and compounds other than olefins that have carbon-carbon double bonds, such as vinyl compounds.

[0094] Olefin components are building blocks derived from olefins. Examples of olefin compounds (olefins) that can be introduced into polyolefin resins include ethylene, propylene, 1-butene, and 4-methyl-1-pentene.

[0095] Examples of the aforementioned polyolefin resins include, for example, low-density polyethylene resin, ultra-low-density polyethylene resin, high-density polyethylene resin, linear low-density polyethylene resin, polypropylene resin, polymethylpentene resin, and resins composed of ethylene-vinyl acetate copolymers.

[0096] When the above component (b1) contains a polyolefin resin, one or more of the polyolefin resins may be used.

[0097] Commercially available polyolefin resins include, for example, NOVATEC PP (manufactured by Nippon Polypropylene Co., Ltd.), NOVATEC LD (manufactured by Mitsubishi Chemical Co., Ltd.), NOVATEC LL (manufactured by Mitsubishi Chemical Co., Ltd.), and NOVATEC HD (manufactured by Mitsubishi Chemical Co., Ltd.).

[0098] <Polydiene resin>

[0099] In this invention, when referred to as a polydiene resin, it is a resin composed of a polymer containing a diene component as a constituent. In this invention, if the polymer contains an olefin component, it is classified as a polyolefin resin even if it contains a diene component. The diene component is a constituent unit derived from a diene compound. Examples of diene compounds that can be introduced into a polydiene resin include 1,3-butadiene and 2-methyl-1,3-butadiene (isoprene).

[0100] Examples of the aforementioned polydiene resins include resins composed of polybutadiene, styrene-butadiene copolymer, polyisoprene, and acrylonitrile-butadiene-styrene copolymer.

[0101] When the above component (b1) contains polydiene resin, one or more of the polydiene resins may be used.

[0102] Commercially available polydiene resins include, for example, JSR1500 (manufactured by JSR Corporation).

[0103] <Polystyrene resin>

[0104] The aforementioned polystyrene resin is a resin composed of a polymer containing styrene as a constituent component. In this invention, when the polymer contains an olefin component, it is classified as a polyolefin resin. Furthermore, when the polymer does not contain an olefin component but does contain a diene component, it is classified as a polydiene resin.

[0105] Examples of polystyrene resins include resins composed of polystyrene, acrylonitrile-styrene copolymers, etc.

[0106] Commercially available polystyrene resins include, for example, CEVIAN N (manufactured by Daicel Corporation).

[0107] <Polyacrylic resins>

[0108] In this invention, when referred to as a polyacrylic resin, it is a resin composed of a polymer having at least one of a component having a (meth)acryloyl group as a constituent and a (meth)acrylonitrile component. In this invention, when these polymers contain an olefin component, they are classified as polyolefin resins. Furthermore, when these polymers do not contain an olefin component but contain a diene component, they are classified as polydiene resins. Additionally, when these polymers do not contain either an olefin component or a diene component but contain a styrene component, they are classified as polystyrene resins. "(meth)acryloyl group" means acryloyl group and / or methacryloyl group. The same applies to "(meth)acrylonitrile".

[0109] The constituent having the above-mentioned (meth)acryloyl group is at least one of (meth)acrylic acid component and (meth)acrylate component. Examples of (meth)acrylates include methyl methacrylate, methyl acrylate, ethyl acrylate, ethyl methacrylate, butyl methacrylate, butyl acrylate, methoxyethyl acrylate, ethoxyethyl acrylate, etc.

[0110] Examples of polyacrylic resins include resins composed of polymethyl methacrylate, polyacrylonitrile, etc.

[0111] Commercially available polyacrylic resins include, for example, ACRYPET VH (manufactured by Mitsubishi Chemical Corporation).

[0112] Polyvinyl resin

[0113] In this invention, when referred to as polyvinyl resin, it is a resin composed of a polymer having components derived from vinyl compounds, that does not belong to any of the above-mentioned polyolefin resins, polydiene resins, polyacrylic resins, or polystyrene resins.

[0114] Examples of the aforementioned polyethylene-based resins include polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl acetate resin, and polyvinyl alcohol resin.

[0115] As a commercially available polyvinyl resin used in this invention, examples include KANEVINYL (manufactured by KANEKA Corporation).

[0116] <Polyester Resin>

[0117] The polyester resin that does not have a naphthalene structure is a polyester resin in which neither the dicarboxylic acid component, the diol component, nor the hydroxycarboxylic acid component has a naphthalene structure. As the dicarboxylic acid component, diol component, and hydroxycarboxylic acid component that can constitute the polyester resin that does not have a naphthalene structure, the components that do not have a naphthalene structure described in the above (a1) polyester resin can be appropriately used.

[0118] Examples of such polyester resins include polyethylene terephthalate and polybutylene terephthalate.

[0119] As a commercially available polyester resin without a naphthalene structure for use in this invention, examples include NOVADURAN 5010CR2 (manufactured by Mitsubishi Chemical Corporation).

[0120] <Polyamide resin>

[0121] The polyamide resin can be either crystalline or amorphous polyamide. Furthermore, in this invention, the term "polyamide resin" refers to a resin containing polyamide-imide.

[0122] Examples of crystalline polyamides include aliphatic polyamides and aromatic polyamides.

[0123] Examples of aliphatic polyamides include poly(ε-hexamethylene)amide (polyamide 6), polynonamide (polyamide 9), polytetramethylene adipamide (polyamide 46), polyhexamethylene adipamide (polyamide 66), polyhexamethylene adipamide / polyhexamethylene adipamide copolymer (polyamide 6 / 66), polyundecanoamide (polyamide 11), polyhexamethylene / polyundecanoamide copolymer (polyamide 6 / 11), polydodecanoamide (polyamide 12), polyhexamethylene / polydodecanoamide copolymer (polyamide 6 / 12), polyhexamethylene decanamide (polyamide 610), polydedecanoamide (polyamide 1010), polyhexamethylene dodecanoamide (polyamide 612), polydedecanoamide (polyamide 1012), polyundecanoamide (polyamide 116), and mixtures or copolymers thereof.

[0124] Examples of aromatic polyamides include polyhexamethylene isophthalamide (polyamide 6I), polyhexamethylene terephthalamide (polyamide 6T), polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (polyamide 6T / 6I), polyhexamethylene terephthalamide / polyhexamethylene terephthalamide copolymer (polyamide 6 / 6T), polyhexamethylene terephthalamide / polyhexamethylene terephthalamide copolymer (polyamide 6 / 6I), polyhexamethylene adipamide / polyhexamethylene terephthalamide copolymer (polyamide 66 / 6T), and polyhexamethylene adipamide. Diamide / polyhexamethylene isophthalamide copolymer (polyamide 66 / 6I), polytrimethylhexamethylene terephthalamide (polyamide TMDT), polybis(4-aminocyclohexyl)methanedodecanoamide (polyamide PACM12), polybis(3-methyl-4-aminocyclohexyl)methanedodecanoamide (nylon dimethyl PACM12), polyadipamide isophthalamide (polyamide MXD6), polydecamethylene terephthalamide (polyamide 10T), polyundemethylene terephthalamide (polyamide 11T), and mixtures or copolymers thereof.

[0125] Examples of non-crystalline polyamides include, for instance, condensates of isophthalic acid / terephthalic acid / 1,6-hexanediamine / bis(3-methyl-4-aminocyclohexyl)methane, condensates of terephthalic acid / 2,2,4-trimethyl-1,6-hexanediamine / 2,4,4-trimethyl-1,6-hexanediamine, condensates of isophthalic acid / bis(3-methyl-4-aminocyclohexyl)methane / ω-laurolamide, and so on. Condensation polymers of formic acid / terephthalic acid / 1,6-hexanediamine, condensation polymers of isophthalic acid / 2,2,4-trimethyl-1,6-hexanediamine / 2,4,4-trimethyl-1,6-hexanediamine, condensation polymers of isophthalic acid / terephthalic acid / 2,2,4-trimethyl-1,6-hexanediamine / 2,4,4-trimethyl-1,6-hexanediamine, and condensation polymers of isophthalic acid / terephthalic acid / other diamine components, etc.

[0126] One or more of the above-mentioned polyamide resins may be used.

[0127] <Polycarbonate resin>

[0128] The aforementioned polycarbonate resin is a polymer composed of constituent components linked by -OC(=O)-O- bonds (a polymer with multiple -OC(=O)-O- bonds in the main chain).

[0129] As a commercially available polycarbonate resin used in this invention, examples include IUPILON S-2000 (manufactured by Mitsubishi Chemical Corporation).

[0130] <Polyurethane Resin>

[0131] The polyurethane resin used in this invention is a resin composed of a polymer (a polymer having multiple urethane bonds in the main chain) whose constituent components are linked by urethane bonds.

[0132] Commercially available polyurethane resins used in this invention include, for example, VULKOLLAN (manufactured by Bayer).

[0133] <Polysulfone resin>

[0134] The aforementioned polysulfone resin is a polymer composed of components linked by sulfonyl groups (-S(=O)2-) (a polymer with multiple -S(=O)2- bonds in the main chain).

[0135] As a commercially available polysulfone resin used in this invention, examples include UDEL P1700 (manufactured by SOLVAY).

[0136] <Polyether resin>

[0137] Polyether resin is a resin composed of polymers whose constituent components are linked by ether bonds (polymers having multiple ether bonds in the main chain). In this invention, even if the polymer has ether bonds in its polymer chain, it is classified as such a resin if it belongs to any of the resins described as component (b1) above.

[0138] Examples of polyether resins include polyphenylene ether resin, polyetherimide resin, polyetherketone resin, and polyetheretherketone resin.

[0139] Fluoropolymers

[0140] The aforementioned fluorinated resin is a polymer having fluorine atoms as substituents. In this invention, if the polymer has fluorine atoms, it is classified as a fluorinated resin even if it also belongs to any of the resins described as component (b1) above.

[0141] Examples of the aforementioned fluorinated resins include polytetrafluoroethylene resin, tetrafluoroethylene-perfluoroalkoxyethylene copolymer, and polyvinylidene fluoride resin.

[0142] Commercially available fluorinated resins include, for example, NEOFLON PFA (manufactured by Daikin Industries).

[0143] The thermoplastic elastomer of the above component (b2) preferably includes at least one of polystyrene elastomer, polyolefin elastomer, polyvinyl chloride elastomer, polyurethane elastomer, polyester elastomer and polyamide elastomer.

[0144] The thermoplastic elastomer of the above component (b2) more preferably includes at least one of polystyrene elastomer and polyolefin elastomer.

[0145] <Polystyrene elastomers>

[0146] The aforementioned polystyrene elastomer is an elastomer having a polystyrene structure as its hard segment. Examples of soft segments include substances having a polybutadiene structure, a polyisoprene structure, or a hydrogenated polybutadiene structure.

[0147] Commercially available polystyrene elastomers include, for example, TEFABLOC 4300C (manufactured by Mitsubishi Chemical Corporation).

[0148] <Polyolefin Elastomers>

[0149] The aforementioned polyolefin elastomers are elastomers with hard segments consisting of crystalline polyethylene or crystalline polypropylene structures. Examples of soft segments include ethylene-propylene-diene rubber (EPDM), polyisobutylene rubber (IIR), ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, chlorinated polyethylene, and amorphous polyethylene.

[0150] Commercially available polyolefin elastomers include, for example, EXCELINK 1700B (manufactured by JSR Corporation).

[0151] <Polyvinyl chloride elastomer>

[0152] The aforementioned polyvinyl chloride elastomers are elastomers with crystalline polyvinyl chloride structures as hard segments. Examples of soft segments include acrylonitrile-butadiene rubber structures and plasticized polyvinyl chloride structures.

[0153] Commercially available polyvinyl chloride elastomers include, for example, SUNPRENE F1469 (manufactured by Mitsubishi Chemical Corporation).

[0154] <Polyurethane Elastomers>

[0155] Examples of polyurethane elastomers include elastomers comprising structural units consisting of hard segments made of glycol and diisocyanate components and soft segments made of polyether or aliphatic polyester.

[0156] Commercially available polyurethane elastomers include, for example, MIRACTRAN (manufactured by MIRACTRAN Corporation of Japan).

[0157] <Polyester Elastomers>

[0158] The polyester elastomer that does not have a naphthalene structure is a polyester elastomer in which none of the dicarboxylic acid component, diol component, and hydroxycarboxylic acid component has a naphthalene structure. The dicarboxylic acid component, diol component, and hydroxycarboxylic acid component that can constitute the polyester elastomer that does not have a naphthalene structure can be appropriately applied to the components described in the polyester elastomer of (a1) above that do not have a naphthalene structure.

[0159] Commercially available polyester elastomers include, for example, ARNITEL EM460 (manufactured by DMS).

[0160] <Polyamide elastomers>

[0161] Examples of polyamide elastomers include multiblock copolymers where the hard segment is polyamide and the soft segment is polyether or polyester. Examples of hard segments include polyamides 6, 66, 610, 11, and 12. Examples of polyethers in the soft segments include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, and other polyalkylene glycols. Examples of polyesters in the soft segments include polyethylene adipate and polybutanediol adipate.

[0162] As a commercially available polyamide elastomer used in this invention, examples include PEBAX 5533 (manufactured by Arkema).

[0163] The aforementioned coating layer may further comprise a compatibilizer. The compatibilizer in this invention is a substance that promotes the miscibility of the component (a) having the aforementioned naphthalene structure with the component (b) not having the aforementioned naphthalene structure. Preferably, the compatibilizer is a compound having a portion that is compatible with the component (a) having the aforementioned naphthalene structure and a portion that is compatible with the component (b) not having the aforementioned naphthalene structure (a non-reactive compatibilizer), or a compound that is reactive with one or both of component (a) and component (b) (a reactive compatibilizer), and more preferably a non-reactive compatibilizer.

[0164] Examples of non-reactive compatibilizers include random polymers such as hydrogenated styrene-butadiene rubber, ethylene-propylene rubber, and ethylene-vinyl acetate copolymer; block polymers such as hydrogenated styrene-butadiene copolymer and hydrogenated styrene-based thermoplastic elastomers; and grafted polymers with polystyrene grafted onto the base of polyethylene or polypropylene.

[0165] Examples of reactive compatibilizers include maleic anhydride-modified polypropylene and ethylene-glycidyl methacrylate copolymer.

[0166] Commercially available non-reactive compatibilizers include, for example, DYNARON (manufactured by JSR Corporation). Commercially available reactive compatibilizers include, for example, BONDFAST (manufactured by Sumitomo Chemical Co., Ltd.).

[0167] The coating layer preferably contains 1 part by mass and less than 5 parts by mass of the compatibilizer relative to 100 parts by mass of the total amount of components (a) and (b). If the amount of the compatibilizer added is within the above range, the formation of the phase separation structure of the coating layer can be sufficiently maintained, while improving the adhesion between the continuous phase and the separated phase, and further improving the barrier properties.

[0168] <Manufacturing Method of Flexible Tubes for Endoscopes>

[0169] By coating a flexible tube substrate with a coating material formed by uniformly blending the above-mentioned components (a) and (b) to form a phase-separated state, a flexible tube for endoscopes can be obtained. Extrusion coating is preferably used to coat the flexible tube substrate. Furthermore, to improve the adhesion between the flexible tube substrate 14 and the coating layer 15 before coating with the coating material, an adhesive layer or a primer layer can be provided on the surface of the flexible tube substrate 14. An example of such an adhesive layer is a layer formed from a composition of a polymer such as polyurethane and a polyisocyanate compound. Another example of a primer layer is a silane coupling agent.

[0170] Endoscopic medical devices

[0171] The flexible tube for endoscopes involved in this invention is not limited to endoscope applications and can be widely used in endoscopic medical devices. It can also be applied to instruments with clamps or wires at the tip of the endoscope, or instruments with baskets or brushes, achieving excellent results. Furthermore, endoscopic medical devices, in addition to medical devices with the endoscope as their basic structure, broadly include, in a broader sense, flexible medical or diagnostic devices that are inserted into the body, such as remotely operated medical devices.

[0172] [Example]

[0173] The present invention will be further described in detail below through embodiments, but the present invention is not limited to these embodiments.

[0174] (Examples 1-38, Comparative Examples 1-4)

[0175] <Fabrication of Coating Material for Flexible Tube Substrates for Endoscopes>

[0176] The raw materials were mixed to form the compositions (parts by mass) listed in Tables 1-5 below. The mixture was then melt-mixed using a twin-screw mixer (product name: KZW15-30MG, manufactured by TECHNOVEL) at a barrel temperature of 270°C and a screw speed of 100 rpm. The molten resin bundles were cooled in a water bath and then granulated to form granular coating materials for flexible endoscope tubes. Component (a) of the coating material, a polyester resin or polyester elastomer with a naphthalene structure, constitutes a substantially continuous phase, while component (b), a thermoplastic resin or thermoplastic elastomer without a naphthalene structure, forms particles with a particle size of approximately 1 μm to 20 μm and constitutes a dispersed phase, thus separating the phases. In this way, the coating material as a whole is in a homogeneous composition state while simultaneously forming a phase-separated state.

[0177] <Preparation of Resin Sheets>

[0178] The endoscope flexible tube substrate coating material obtained above was heated to 270°C and pressurized at 10 MPa for 30 seconds using a small experimental pressurizer (manufactured by Toyo Seiki Co., Ltd.) to form a thin film sheet (hereinafter also referred to as "polyester sheet") with a thickness of 0.01 mm, a length of 10 cm and a width of 10 cm.

[0179] [Experimental Example 1] Barrier Test

[0180] Using the obtained sheet material, according to JIS Z0208, a moisture permeability test was conducted under the conditions of 60℃, 90%RH, and 96 hours. The obtained water vapor permeability was compared with the barrier performance evaluation criteria below to evaluate the water vapor barrier performance. The results are shown in Tables 1 to 5 below.

[0181] <Barrier Assessment Criteria>

[0182] S: Water vapor permeability is less than 5 g / m 2 ·96 hours.

[0183] A: Water vapor permeability is 5g / m 2 • More than 96 hours and less than 10g / m 2 ·96 hours.

[0184] B: Water vapor permeability is 10 g / m 2 • More than 96 hours and less than 20g / m 2 ·96 hours.

[0185] C: Water vapor permeability is 20 g / m 2 • More than 96 hours and less than 30g / m 2 ·96 hours.

[0186] D: Water vapor permeability is 30 g / m 2• More than 96 hours.

[0187] [Experimental Example 2] Evaluation of Ozone Water Tolerance

[0188] The polyester sheet prepared above was placed in a glass box measuring 20cm long × 20cm wide × 1cm thick. The glass box containing the polyester sheet was then placed in the flow path of an ozone water generator (trade name: EcoDesign "OWM-10L10P"), and ozone water with an ozone concentration of 3ppm was allowed to flow at a flow rate of 1L / min for 3 hours for treatment. Afterwards, the sheet was washed with distilled water and dried at 23°C × 50% RH (relative humidity) for 24 hours. A tensile test was then performed using a TENSILON universal testing machine (trade name: RTF-1210, A&D Corporation). The results were evaluated against the following criteria (100% elongation means elongation to twice the original length). The results are shown in Tables 1-5 below.

[0189] <Ozone Water Tolerance Evaluation Criteria>

[0190] S: It did not break even when the elongation reached 200%.

[0191] A: It did not break even when the elongation reached 150%, but it broke before the elongation reached 200%.

[0192] B: It did not break even when the elongation reached 100%, but broke before the elongation reached 150%.

[0193] C: It breaks before the elongation reaches 100%.

[0194] [Table 1]

[0195]

[0196] [Table 2]

[0197]

[0198] [Table 3]

[0199]

[0200] [Table 4]

[0201]

[0202] [Table 5]

[0203]

[0204] <Explanation of terms in the table>

[0205] -Compound 1-1 used in the examples: Polyester elastomer with a naphthalene structure (trade name: PELPRENE EN, manufactured by Toyobo Co., Ltd.)

[0206] 1-2: Polyester resin with naphthalene structure (trade name: TQB-OT, manufactured by Teijin Chemical Co., Ltd., polybutylene dinaphthalate)

[0207] 2-1: Polyolefin resin (trade name: NOVATEC PP, manufactured by Nippon Polypropylene Co., Ltd.)

[0208] 2-2: Polydiene resin (trade name: JSR1500, manufactured by JSR Corporation)

[0209] 2-3: Polyacrylic acid resin (trade name: ACRYPET VH, manufactured by Mitsubishi Chemical Corporation)

[0210] 2-4: Polystyrene resin (trade name: CEVIAN N, manufactured by Daicel Corporation)

[0211] 2-5: Polyvinyl resin (trade name: KANEVINYL M1008, manufactured by KANEKA Corporation)

[0212] 2-6: Polyester resin (trade name: NOVADURAN 5010CR2, manufactured by Mitsubishi Chemical Corporation)

[0213] 2-7: Polyamide resin (trade name: UBESTA, manufactured by Ube Industries, Inc.)

[0214] 2-8: Polycarbonate resin (trade name: IUPILON S-2000, manufactured by Mitsubishi Chemical Corporation)

[0215] 2-9: Polyurethane resin (trade name: VULKOLLAN, manufactured by Bayer AG)

[0216] 2-10: Polyether resin (trade name: VICTREX PEEK, manufactured by VICTREX Corporation)

[0217] 2-11: Polyether resin (trade name: IUPIACE, manufactured by Mitsubishi Engineering Plastics, polyphenylene ether)

[0218] 2-12: Polysulfone resin (trade name: UDEL P1700, manufactured by SOLVAY)

[0219] 2-13: Polysulfone resin (trade name: RADEL A, manufactured by SOLVAY, polyethersulfone)

[0220] 2-14: Polyether resin (trade name: polyetherimide, manufactured by SABIC, polyetherimide)

[0221] 2-15: Polyamide resin (trade name: TI-5013, manufactured by Toray Industries, Inc., polyamide-imide)

[0222] 2-16: Fluoropolymer (trade name: NEOFLON PFA, manufactured by Daikin Industries)

[0223] 3-1: Polystyrene elastomer (trade name: TEFABLOC 4300C, manufactured by Mitsubishi Chemical Corporation)

[0224] 3-2: Polyolefin elastomer (trade name: EXCELINK 1700B, manufactured by JSR Corporation)

[0225] 3-3: Polyvinyl chloride elastomer (trade name: SUNPRENE F1469, manufactured by Mitsubishi Chemical Corporation)

[0226] 3-4: Polyurethane elastomer (trade name: MIRACTRAN E385, manufactured by MIRACTRAN Corporation, Japan)

[0227] 3-5: Polyester elastomer (trade name: ARNITEL EM460, manufactured by DMS)

[0228] 3-6: Polyamide elastomer (trade name: PEBAX5533, manufactured by Arkema)

[0229] 4-1: Non-reactive compatibilizer (trade name: DYNARON, manufactured by JSR Corporation)

[0230] 4-2: Reactive compatibilizer (trade name: BONDFAST, manufactured by Sumitomo Chemical Co., Ltd.)

[0231] 5-1: Crosslinking agent (trade name: CARBODILITE LA-1, manufactured by Nisshinbo Co., Ltd.)

[0232] The above 2-1 to 5-1 do not have a naphthalene structure.

[0233] As shown in Tables 1 to 5, when the coating material is composed of a resin with a naphthalene structure and no phase separation structure is formed, the resulting sheet has poor water vapor barrier properties (Comparative Example 1). Furthermore, if a compatibilizer is added, the ozone water resistance also deteriorates (Comparative Example 4). Additionally, even if the coating material is a blend of components (a) and (b) and a phase separation structure is formed, if the content of component (a) is less than that specified in this invention, both barrier properties and ozone water resistance are poor (Comparative Examples 2 and 3).

[0234] In contrast, when the coating material is a blend of components (a) and (b) forming a phase-separated structure, and the contents of each component also meet the requirements of this invention 1, the 0.01 mm thick film sheet formed from this coating material exhibits excellent water vapor barrier properties and excellent ozone water resistance (Examples 1-38). Furthermore, it is known that when the coating material is a blend of components (a) and (b), adding a compatibilizer is effective in simultaneously improving the barrier properties and ozone water resistance of the resulting sheet.

[0235] The invention has been described together with its embodiments, but we believe that, unless otherwise specified, our invention should not be limited to any of the details described, and should be interpreted broadly without departing from the spirit and scope of the invention as set forth in the appended claims.

[0236] This application claims priority based on Japanese Patent Application No. 2020-111756, filed on June 29, 2020, the contents of which are incorporated herein by reference and incorporated herein by reference as part of the description.

[0237] Symbol Explanation

[0238] 2. Electronic endoscope (endoscope)

[0239] 3 Insertion section

[0240] 3a flexible tube

[0241] 3b bend

[0242] 3C top

[0243] 5 Main Operating Section

[0244] 6 Universal Rope

[0245] 11 spiral tube

[0246] 11a metal strip

[0247] 12 cylindrical mesh

[0248] 13 pipe heads

[0249] 14 Flexible tube substrate

[0250] 15 covering layers

Claims

1. A flexible tube for an endoscope, comprising: Flexible tubular flexible tube substrate, and The coating of the flexible tube substrate, in, The coating layer contains components a and b, wherein component a accounts for more than 50% by mass and less than 90% by mass of the total amount of components a and b, and components a and b are separated from each other in the coating layer. The component a is at least one of a1 and a2. a1 is a polyester resin with a naphthalene structure. a2 is a polyester elastomer with a naphthalene structure; The component b is at least one of b1 and b2. b1 is a thermoplastic resin that does not have a naphthalene structure. b2 is a thermoplastic elastomer without a naphthalene structure; b1 includes at least one of polystyrene resin, polyester resin, and polyamide resin. b2 includes at least one of polystyrene elastomer, polyester elastomer, and polyamide elastomer.

2. The flexible endoscope tube according to claim 1, wherein, The b1 includes at least one of polyester resin and polyamide resin, and the coating layer contains a compatibilizer.

3. The flexible endoscope tube according to claim 1 or 2, wherein, The b2 comprises at least one of polyester elastomer and polyamide elastomer, and the coating layer contains a compatibilizer.

4. The flexible endoscope tube according to claim 1 or 2, wherein, The coating layer has a phase separation state in which component a is the continuous phase and component b is the dispersed phase. The dispersed phase is in the form of particles with a particle size of 1 to 50 μm when viewed from above.

5. An endoscopic medical device comprising an endoscope flexible tube according to any one of claims 1 to 4.

6. A coating material for a flexible tube substrate for an endoscope, comprising components a and b, wherein component a accounts for more than 50% by mass and less than 90% by mass of the total amount of components a and b, and components a and b are separated from each other. The component a is at least one of a1 and a2. a1 is a polyester resin with a naphthalene structure. a2 is a polyester elastomer with a naphthalene structure; The component b is at least one of b1 and b2. b1 is a thermoplastic resin that does not have a naphthalene structure. b2 is a thermoplastic elastomer without a naphthalene structure. b1 includes at least one of polystyrene resin, polyester resin, and polyamide resin. b2 includes at least one of polystyrene elastomer, polyester elastomer, and polyamide elastomer.

7. The coating material for the flexible tube substrate of an endoscope according to claim 6, wherein, The coating material has a phase separation state in which component a is the continuous phase and component b is the dispersed phase. The dispersed phase is in the form of particles with a particle size of 1 to 50 μm when viewed from above.

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