Flexible tube for endoscope, endoscope-type medical instrument, and method for manufacturing the same

Abstract

The present application provides a flexible tube for an endoscope, an endoscope medical instrument using the same, and a manufacturing method for each of the flexible tube for an endoscope and the endoscope medical instrument, the flexible tube for an endoscope having a flexible tube base material in a cylindrical shape and a coating layer covering an outer periphery of the flexible tube base material, wherein the coating layer contains a chain extender of a polyester having a naphthalene structure, the chain extender containing a constituent component from at least one chain extender among (A) an epoxy compound, (B) an isocyanate compound, (C) an amine compound, (D) an oxazoline compound, (E) a carbodiimide compound having a molecular weight lower than 3,000, and (F) a carboxylic anhydride, and a constituent component from a polyester having a naphthalene structure.

Description

Technical Field

[0001] This invention relates to a flexible tube for endoscopes, an endoscopic medical device, and a method for manufacturing the same. 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 or discomfort for the patient. Considering these requirements, the flexible tube constituting the insertion part of the endoscope is a spiral tube formed by winding a soft, curved metal strip into a helix. Furthermore, it is coated with a soft resin 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. The flexible tube that forms the insertion part of the endoscope needs to be cleaned and disinfected 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 have a high degree of durability that can withstand repeated sterilization processes.

[0004] For example, Patent Document 1 describes a flexible endoscope tube covered with an outer skin made of an endoscope elastomer molded body, which is less likely to cause outer skin deterioration due to various drugs. The endoscope elastomer molded body is made by cross-linking two or more thermoplastic polyester elastomers.

[0005] Patent document 2 describes an endoscope flexible tube with an outer skin consisting of two resin layers that has excellent peracetic acid resistance. The two resin layers are either a resin layer containing one or more elastomers or chain extenders selected from the group consisting of polyester elastomers, polyurethane elastomers and polyamide elastomers, or a resin layer containing chain extenders of two or more elastomers selected from the group consisting of polyester elastomers, polyurethane elastomers and polyamide elastomers.

[0006] Patent document 3 describes a flexible endoscope tube formed by coating the surface of a flexible tube material with an outer skin. In this case, by using polybutylene naphthalene dicarboxylate in the hard segments of the polyester elastomer constituting the outer skin, the deterioration of the outer skin caused by cleaning or disinfecting solutions is suppressed, and the durability for sterilization treatment using an autoclave is also improved.

[0007] Patent document 4 describes a thermoplastic resin composition containing a resin having a polybutylene succinate chain and one or more copolymer resins selected from the group consisting of aliphatic ether ester copolymer resins and aliphatic ether amide copolymer resins, which has excellent heat resistance for sterilization at high temperatures, and the tube body of a flexible tube for endoscopes is formed using this composition.

[0008] In addition, Patent Document 5 describes that the resin layer used as the substrate of the coated flexible tube is composed of 10% thermoplastic resin with a tensile strength of 10 MPa or more, and a hindered amine compound with a molecular weight of 500 or more is mixed in the resin. Therefore, the resin layer is not prone to deterioration regardless of repeated hydrogen peroxide plasma treatment or repeated hydrogen peroxide gas treatment.

[0009] Previous technical documents

[0010] Patent documents

[0011] Patent Document 1: Japanese Patent Application Publication No. 2009-183467

[0012] Patent Document 2: Japanese Patent Application Publication No. 2014-188217

[0013] Patent Document 3: Japanese Patent Application Publication No. 2004-141487

[0014] Patent Document 4: Japanese Patent Application Publication No. 2010-189598

[0015] Patent Document 5: International Publication No. 2019 / 189035 Summary of the Invention

[0016] The technical problem to be solved by the invention

[0017] Regarding the sterilization durability of flexible endoscope tubes, in recent years, from the perspective of suppressing the deterioration of flexible endoscope tubes due to moist heat, chemical sterilization treatments using hydrogen peroxide plasma, hydrogen peroxide gas, etc., have been widely adopted instead of autoclave treatment. Furthermore, recently, sterilization treatment using ozonated water, prepared by dissolving trace amounts of ozone (O3) in water, has begun. This ozonated water generates potent 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.

[0018] Furthermore, in order to smoothly and reliably deliver the endoscope insertion part to the affected area, the endoscope insertion part is repeatedly bent. Therefore, the endoscope insertion part is required to have the characteristics of not easily peeling off the flexible tube substrate and the coating of the flexible tube substrate, and not easily cracking the coating, even when repeatedly bent (bending durability).

[0019] In addition, in order to insert the endoscope into the body without giving the patient a foreign body sensation and to deliver it smoothly and reliably to the affected area, the flexible tube of the endoscope is required to not only have improved bending durability, but also a smooth surface without bumps and unevenness, and excellent lubricity with the inner surfaces of body cavities, digestive tract, esophagus, etc., that is, excellent surface smoothness.

[0020] In view of the above, an object of the present invention is to provide an endoscope flexible tube that exhibits excellent sterilization durability against powerful sterilization treatments such as ozone water, and also exhibits excellent bending durability and surface smoothness, as well as an endoscope-type medical device using the same. Furthermore, an object of the present invention is to provide a method for manufacturing both the aforementioned endoscope flexible tube and the aforementioned endoscope-type medical device.

[0021] means for solving technical problems

[0022] The inventors have conducted in-depth research on the above-mentioned problems and have found that, as a constituent material of the coating (outer skin) of the flexible tube for endoscopes, a polyester having a constituent component derived from a specific chain extender and incorporating a naphthalene structure is used in the coating of the flexible tube for endoscopes, thereby solving the above-mentioned problems and thus completing the present invention.

[0023] The above objectives can be achieved through the following methods.

[0024] <1>

[0025] An endoscope flexible tube comprises a flexible cylindrical flexible tube substrate and a coating covering the outer periphery of the flexible tube substrate, wherein,

[0026] The aforementioned coating layer comprises a chain extender of a polyester having a naphthalene structure.

[0027] The aforementioned chain extender comprises a component from at least one chain extender selected from (A) an epoxy compound, (B) an isocyanate compound, (C) an amine compound, (D) an oxazoline compound, (E) a carbodiimide compound with a molecular weight less than 3,000, and (F) a carboxylic anhydride, and a component from a polyester having a naphthalene structure.

[0028] <2>

[0029] according to <1> The flexible tube for the endoscope, wherein,

[0030] The chain extender of the polyester having the naphthalene structure described above includes components from the epoxy compound described above (A), and the components from the epoxy compound described above (A) include components from di- to hexafunctional epoxy compounds.

[0031] <3>

[0032] according to <1> or <2> The flexible tube for the endoscope, wherein,

[0033] The chain extender of the polyester having the naphthalene structure described above includes components from the isocyanate compound described above (B), and the components from the isocyanate compound described above (B) include components from difunctional or trifunctional isocyanate compounds.

[0034] <4>

[0035] according to <1> ~ <3> The flexible tube for the endoscope described in any one of the following statements, wherein,

[0036] The chain extender of the polyester having the naphthalene structure described above includes components derived from the above-mentioned (C) amine compound, which includes components derived from di- to tetrafunctional amine compounds.

[0037] <5>

[0038] according to <1> ~ <4> The flexible tube for the endoscope described in any one of the following statements, wherein,

[0039] The chain extender of the polyester having the naphthalene structure described above includes components derived from the (D) oxazoline compound described above, including components derived from high molecular weight oxazoline compounds.

[0040] <6>

[0041] according to <1> ~ <5> The flexible tube for the endoscope described in any one of the following statements, wherein,

[0042] The chain extender of the polyester having a naphthalene structure comprises a component from the carbodiimide compound with a molecular weight of less than 3,000 in the above (E) and the component from the carbodiimide compound with a molecular weight of less than 3,000 in the above (E) includes a component from a carbodiimide compound having a cyclic structure.

[0043] <7>

[0044] according to <1> ~ <6> The flexible tube for the endoscope described in any one of the following statements, wherein,

[0045] The chain extender of the polyester having the naphthalene structure described above contains components derived from the carboxylic anhydride described above, including components derived from tetracarboxylic dianhydride.

[0046] <8>

[0047] An endoscopic medical device, which has <1> ~ <7> The flexible tube for endoscopes as described in any one of these descriptions.

[0048] <9>

[0049] A method for manufacturing a flexible tube for an endoscope, comprising:

[0050] A coating is formed on at least the outer periphery of a flexible tubular substrate using a coating forming material comprising at least one chain extender selected from (A) an epoxy compound, (B) an isocyanate compound, (C) an amine compound, (D) an oxazoline compound, (E) a carbodiimide compound with a molecular weight less than 3,000, and (F) a carboxylic anhydride, and a polyester having a naphthalene structure.

[0051] <10>

[0052] A method for manufacturing an endoscopic medical device, comprising:

[0053] By according to <9> The method for manufacturing a flexible endoscope tube includes the steps for obtaining the flexible endoscope tube; and

[0054] The process of assembling the obtained endoscope into the insertion part of an endoscopic medical device using a flexible tube.

[0055] <11>

[0056] A method for manufacturing an endoscopic medical device, comprising:

[0057] Will <1> ~ <7> The flexible tube for endoscopes described in any one of these applications is assembled into the insertion portion of an endoscopic medical device.

[0058] In this specification, the term "compound not explicitly described as substituted or unsubstituted" means that it may have substituents within the range to achieve the desired effect.

[0059] In this specification, when specifying the number of carbon atoms of a certain group, the number of carbon atoms refers to the total number of carbon atoms of the group. That is, when the group is further substituented, the number of carbon atoms refers to the total number of carbon atoms including the substituent.

[0060] In addition, in this specification, “~” is used to mean both the lower and upper limits, including the values ​​described before and after it.

[0061] Invention Effects

[0062] The flexible endoscope tube of the present invention exhibits excellent sterilization durability under strong sterilization treatments such as ozone water, and also demonstrates excellent bending durability and surface smoothness. The endoscopic medical device of the present invention is an instrument incorporating the flexible endoscope tube possessing the aforementioned excellent properties. Furthermore, according to the manufacturing method of the flexible endoscope tube of the present invention, it is possible to obtain the flexible endoscope tube of the present invention possessing the aforementioned properties. According to the manufacturing method of the endoscopic medical device of the present invention, it is possible to obtain an endoscopic medical device incorporating the flexible endoscope tube of the present invention possessing the aforementioned properties. Attached Figure Description

[0063] Figure 1 This is an external diagram showing the structure of an electronic endoscope.

[0064] Figure 2 This is a partial cross-sectional view showing the general structure of the flexible tube used for endoscopy. Detailed Implementation

[0065] Flexible tubes for endoscopes

[0066] The flexible tube for endoscopes of the present invention (hereinafter, sometimes referred to simply as "flexible tube") is a flexible tube for endoscopes having a flexible cylindrical flexible tube substrate and a coating layer covering the outer periphery of the flexible tube substrate, wherein the coating layer comprises a chain extender of a polyester having a naphthalene structure.

[0067] The chain extender of the polyester having a naphthalene structure is a polymer obtained by chain extending the polyester having a naphthalene structure using at least one chain extender selected from (A) an epoxy compound, (B) an isocyanate compound, (C) an amine compound, (D) an oxazoline compound, (E) a carbodiimide compound with a molecular weight of less than 3,000, and (F) a carboxylic anhydride. That is, the chain extender of the polyester having a naphthalene structure comprises components derived from at least one chain extender selected from (A) an epoxy compound, (B) an isocyanate compound, (C) an amine compound, (D) an oxazoline compound, (E) a carbodiimide compound with a molecular weight of less than 3,000, and (F) a carboxylic anhydride, and components derived from the polyester having a naphthalene structure.

[0068] The flexible tube of this invention exhibits excellent sterilization durability even under strong sterilization treatments such as ozone water, as well as excellent bending durability and, consequently, excellent surface smoothness. Specifically, it can be considered that polyesters with a naphthalene structure, due to the size of the naphthalene structure's molecular area, possess a barrier function that hinders the transfer and penetration of sterilizing active species such as hydroxyl radicals into the coating layer. It can be considered that, in this invention, by using a specific chain extender to designate the polyester with this structure as a chain extender (crosslinker), the aforementioned barrier function is effectively improved. Furthermore, it can be considered that, in the coating layer, the naphthalene structure of the chain extender also hinders the movement of unreacted chain extenders to the coating layer surface during thermoforming, and by designing it as a chain extender, an appropriate crosslinking density and high molecular weight are achieved, thereby improving the properties required for endoscopes, such as surface smoothness, flexibility, and fatigue resistance.

[0069] (Covering layer)

[0070] The flexible tube of the present invention has a coating layer on the outer periphery of the flexible tube substrate. The flexible tube of the present invention may also have an intermediate layer on the flexible tube substrate, in which case the flexible tube of the present invention has a coating layer on the intermediate layer.

[0071] In this invention, the coating layer can be a single layer or a multilayer structure with two or more layers, preferably a single layer. In the case of a single-layer coating layer, the single-layer coating layer contains a chain extender of a polyester having a naphthalene structure. Furthermore, in the case of a multilayer structure with two or more layers, at least the outermost layer contains a chain extender of a polyester having a naphthalene structure. That is, in this invention, the outermost layer of the coating layer contains a chain extender of a polyester having a naphthalene structure.

[0072] -Polyesters with naphthalene structures-

[0073] Examples of polyesters having a naphthalene structure include polyester resins having a naphthalene structure and polyester elastomers having a naphthalene structure.

[0074] As a polyester having the naphthalene structure, a preferred example is a polyester composed of a dicarboxylic acid component (a component derived from naphthalene dicarboxylic acid) and a diol component (a component derived from diol).

[0075] A specific example of a preferred dicarboxylic acid component as the aforementioned naphthalenedicarboxylic acid component is 2,6-naphthalenedicarboxylic acid.

[0076] First, polyester resins with naphthalene structures will be explained.

[0077] Polyester resins with a naphthalene structure preferably contain naphthalene dicarboxylic acid. Polyester resins containing naphthalene dicarboxylic acid may also contain dicarboxylic acid components other than naphthalene dicarboxylic acid as dicarboxylic acid components.

[0078] Other than naphthalene dicarboxylic acid, the aforementioned dicarboxylic acid components are not particularly limited, and substances commonly used as dicarboxylic acid components in polyester resins can be widely used. Examples include components derived from terephthalic acid, isophthalic acid, ortho-phthalic acid, sodium isophthalate-5-sulfonate, oxalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, dodecanoic acid, dimer acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, mesocarboxylic acid, and cyclohexanedicarboxylic acid. One or more of these dicarboxylic acid components may be used.

[0079] Polyester resins with a naphthalene structure can be widely used with substances commonly used as diol components in polyester resins. Examples include components derived from 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 can be used.

[0080] The aforementioned polyester resins with a naphthalene structure can also be composed of 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.

[0081] The aforementioned polyester resin with a naphthalene structure 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 tetroxide, trimethylolpropane, glycerol, and pentaerythritol.

[0082] In addition, as the polyester resin having the naphthalene structure described above, it can be used in combination with two or more homopolymers or copolymers composed of the above components.

[0083] Next, polyester elastomers with naphthalene structures will be described.

[0084] Polyester elastomers having a naphthalene structure preferably have a naphthalene dicarboxylic acid component. More preferably, they are copolymers 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 constituents, and the soft segments are at least any one of (i) to (iii) below.

[0085] (i) Amorphous soft segments composed of aliphatic polyester chains;

[0086] (ii) Amorphous soft segments composed of aliphatic polymer diol components;

[0087] (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.

[0088] 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.

[0089] A specific example of a preferred dicarboxylic acid component as the aforementioned naphthalene dicarboxylic acid component is 2,6-naphthalene dicarboxylic acid. The following describes polyester elastomers with naphthalene structures in their hard segments.

[0090] 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, and the hard segments may also contain dicarboxylic acid components other than naphthalene dicarboxylic acid. As dicarboxylic acid components other than naphthalene dicarboxylic acid components constituting the hard segments, substances commonly used as dicarboxylic acid components constituting the hard segments can be widely used. Examples include dicarboxylic acid components other than naphthalene dicarboxylic acid components described in the description of polyester resins with a naphthalene structure; 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% or more by mass (preferably 70% or more by mass, more preferably 80% or more by mass, more preferably 90% or more by mass) 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.

[0091] As the diol component constituting the aforementioned hard segments, substances commonly used as diol components constituting polyester resins can be widely used. Examples include the diol components described in polyester resins having a naphthalene structure, and one or more of these diol components may be present.

[0092] The aforementioned hard segments may contain one or more of the hydroxycarboxylic acid components described in the instructions for polyester resins with naphthalene structures as constituent components.

[0093] The aforementioned hard segments can be homopolymers composed of the constituent components described above, or they can be copolymers.

[0094] 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.

[0095] 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 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 even more preferably 2 to 6. In addition, n is preferably 5 to 100, more preferably 10 to 50.

[0096] 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 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.

[0097] 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.

[0098] Polyesters with a naphthalene structure, when reacting with a chain extender to form a chain extender, thus possess at least one functional group that reacts with the functional groups present in the chain extender, such as hydroxyl and carboxyl groups, or at least one of these groups is formed during the heating and mixing process described above. The polyester may possess these functional groups in at least one of the polymer's main chain and side chains, preferably at one or both ends of the main chain. These functional groups can be introduced into the polyester, for example, by selecting the raw materials used to synthesize the polyester, or by adjusting the conditions for stopping the polymerization reaction. Furthermore, these functional groups can also be generated through the hydrolysis of the polyester, etc.

[0099] For example, the functional group equivalent (weight-average molecular weight of each of the above functional groups) of the polyester can be appropriately determined by taking into account the functional number and functional group equivalent of the chain extender.

[0100] Examples of commercially available polyesters with a naphthalene structure include TQB-KET30 (trade name, manufactured by Teijin Chemical Co., Ltd.) and PELPRENE EN type (trade name, manufactured by Toyobo Co., Ltd.).

[0101] Polyesters with naphthalene structures can be used alone or in combination of two or more.

[0102] When the coating layer is a single layer, the content of the polyester chain extender having a naphthalene structure in the coating layer, and when the coating layer is multilayer, the content of the polyester chain extender having a naphthalene structure in the outermost layer, is preferably 50% by mass or more, more preferably 60% by mass or more, further preferably 70% by mass or more, further preferably 80% by mass or more, and further preferably 90% by mass or more. Furthermore, when the coating layer is a single layer, it can be a layer composed of a polyester chain extender having a naphthalene structure; when the coating layer is multilayer, the outermost layer can be a layer composed of a polyester chain extender having a naphthalene structure.

[0103] When the coating layer is a single layer, and when the coating layer is multilayered, the outermost layer can be a blend of at least one of a polyester chain extender having a naphthalene structure, or a polymer other than a polyester having a naphthalene structure and its chain extender. In this case, polymers commonly used as coating materials for flexible tubes for endoscopes can be widely used as polymers other than polyesters having a naphthalene structure. Examples of such polymers include polyesters without a naphthalene structure, polyurethanes, and polyamides.

[0104] When the coating is multilayered, the layers other than the outermost layer preferably contain at least one of a polyester having a naphthalene structure and its chain extender.

[0105] The polymers and their chain extenders used in the coating layer of the present invention preferably have a molecular weight of 10,000 to 1,000,000, more preferably a molecular weight of 20,000 to 500,000, and even more preferably a molecular weight of 50,000 to 300,000.

[0106] In this invention, unless otherwise specified, the molecular weight of the polymer constituting the coating layer refers to the weight-average molecular weight. The weight-average molecular weight can be measured as the molecular weight equivalent to polystyrene using gel permeation chromatography (GPC). Specific measurement conditions are shown below.

[0107] The determination can be performed using a GPC apparatus HLC-8220 (trade name, manufactured by Tosoh Corporation), with chloroform as the eluent and G3000HXL+G2000HXL (both trade names, manufactured by Tosoh Corporation) as the chromatographic column, at 23°C and a flow rate of 1 mL / min, by gel permeation chromatography with detection using an RI (differential refractive index) detector.

[0108] In this application specification, the number-average molecular weight can be determined under the same conditions as the weight-average molecular weight described above. In this application specification, when a range of weight-average molecular weights for a compound is described, this range is preferably also used as the range of number-average molecular weights for that compound.

[0109] -Chain extender-

[0110] The chain extender of the naphthalene-structured polyester used in this invention is prepared using at least one chain extender selected from (A) an epoxy compound, (B) an isocyanate compound, (C) an amine compound, (D) an oxazoline compound, (E) a carbodiimide compound with a molecular weight less than 3,000, and (F) a carboxylic anhydride.

[0111] (A) Epoxy compounds

[0112] The epoxy compound used as a chain extender in this invention is not particularly limited, and epoxy compounds described in, for example, Japanese Patent Application Publication No. 2008-115293 may be used.

[0113] The epoxy compound can be either a monofunctional epoxy compound or a polyfunctional epoxy compound, with polyfunctional epoxy compounds being preferred. From the perspective of the sterilization durability, bending durability, and surface smoothness of the flexible endoscope tube, the polyfunctional epoxy compound preferably has 2 to 6 functions (the number of epoxy groups per molecule), more preferably 2 to 5, and even more preferably 2 to 4.

[0114] The molecular weight of the epoxy compound is preferably 100 to 1,000, more preferably 200 to 600. When the epoxy compound has a molecular weight distribution, its weight-average molecular weight (Mw) is preferably 200 to 1,000, more preferably 300 to 800. In this invention, the weight-average molecular weight of the chain extender can be measured using GPC as the weight-average molecular weight converted from polystyrene. Specific measurement conditions are shown below.

[0115] The determination can be performed using a GPC apparatus HLC-8220 (trade name, manufactured by Tosoh Corporation), with tetrahydrofuran as the eluent and G3000HXL+G2000HXL (both trade names, manufactured by Tosoh Corporation) as the chromatographic column, at 23°C and a flow rate of 1 mL / min, by gel permeation chromatography with a RI (differential refractive index) detector.

[0116] The functional group equivalent (molecular weight or weight-average molecular weight of each epoxy group) of the epoxy compound is not particularly limited, but is preferably 50 to 300, more preferably 70 to 200.

[0117] Specific examples of epoxy compounds include diglycidyl ethers of diphenols (diglycidyl ethers comprising a structure from a compound having two hydroxyl groups bonded to a benzene ring or a naphthalene ring), polyglycidyl ethers of poly(three or more) phenols (diglycidyl ethers comprising a structure from a compound having three or more hydroxyl groups bonded to a benzene ring or a naphthalene ring), diglycidyl ethers of aliphatic diols or high molecular weight diols, polyglycidyl ethers of three or more aliphatic alcohols, epoxy-modified polysiloxanes, glycidyl esters, glycidyl amines, chain aliphatic epoxides, alicyclic epoxides, and urethane-modified epoxy compounds having urethane bonds in their structure.

[0118] The diglycidyl ether used as the aforementioned diphenol is not particularly limited, but diglycidyl ethers of diphenols (with 6 to 30 carbon atoms) are preferred. Examples include bisphenol F diglycidyl ether, bisphenol A diglycidyl ether, bisphenol B diglycidyl ether, bisphenol AD ​​diglycidyl ether, bisphenol S diglycidyl ether, halogenated bisphenol A diglycidyl ether (e.g., tetrachlorobisphenol A diglycidyl ether), catechol diglycidyl ether, resorcinol diglycidyl ether, hydroquinone diglycidyl ether, 1,6-dihydroxynaphthalene diglycidyl ether, dihydroxybiphenyl diglycidyl ether, octachloro-4,4'-dihydroxybiphenyl diglycidyl ether, tetramethylbiphenyl diglycidyl ether, 9,9'-bis(4-hydroxyphenyl)fluorene diglycidyl ether, and diglycidyl ether obtained by reacting 2 moles of bisphenol A with 3 moles of epichlorohydrin.

[0119] Polyglycidyl ethers of the aforementioned polyphenols (three or more) are not particularly limited, but polyglycidyl ethers with 6 or more carbon atoms and Mw of 5,000 or less are preferred. Examples include pyrogallol triglycidyl ether, dihydroxynaphthylcresol triglycidyl ether, tris(hydroxyphenyl)methane triglycidyl ether, dinaphthyltriol triglycidyl ether, 4,4'-oxybis(1,4-phenylethyl)phenyl glycidyl ether, and bis(dihydroxynaphthyl)tetraglycidyl ether. Glycidyl ethers of ethers, phenols or cresol phenolic resins (Mw200-5,000), glycidyl ethers of limonene phenolic resins (Mw400-5,000), polyglycidyl ethers of polyphenols (Mw400-5,000) obtained by the condensation reaction of phenol with glyoxal, glutaraldehyde or formaldehyde, and polyglycidyl ethers of polyphenols (Mw400-5,000) obtained by the condensation reaction of resorcinol with acetone, etc.

[0120] The diglycidyl ether of the aforementioned aliphatic diol or high molecular weight diol is not particularly limited, but is preferably aliphatic diol or high molecular weight diol with 2 to 100 carbon atoms, such as ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tetramethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, polyethylene glycol (Mw150 to 4,000) diglycidyl ether, polypropylene glycol (Mw180 to 5,000) diglycidyl ether, polytetramethylene glycol (Mw200 to 5,000) diglycidyl ether, neopentyl glycol diglycidyl ether, etc.

[0121] The polyglycidyl ether that is a trivalent or higher aliphatic alcohol is not particularly limited, but is preferably a glycidyl ether with 3 or more carbon atoms and Mw of 10,000 or less. Examples include trimethylolpropane triglycidyl ether, glycerol triglycidyl ether, pentaerythritol tetraglycidyl ether, sorbitol hexaglycidyl ether, and poly(n(the number of repetitions of "-CH2-CH(OH)-CH2-O-") = 2 to 5) glycerol polyglycidyl ether.

[0122] The epoxy-modified polysiloxanes mentioned above are not particularly limited, but glycidyl ethers of polydialkylsiloxanes (e.g., polydimethylsiloxane) with a Mw of 200 to 2,000 having two or more hydroxyl groups are preferred. Examples include 1,3-bis(3-epoxypropoxypropyl)-1,1,3,3-tetramethyldisiloxane and 1,3-bis(3-epoxypropoxypropyl)-1,1,3,3-poly(n(repetition number of "-Si-O-") = 2 to 20)tetramethyldisiloxane.

[0123] The glycidyl esters mentioned above are not particularly limited, but preferably are glycidyl esters of aromatic carboxylic acids, aliphatic carboxylic acids, or alicyclic carboxylic acids having 6 or more carbon atoms and being divalent or more. Examples include glycidyl esters of phthalic acids (diglycidyl phthalate, diglycidyl isophthalate, diglycidyl terephthalate, etc.), triglycidyl trimellitate, and other aromatic carboxylic acids; aromatic nucleohydrides of the glycidyl esters of the above-mentioned aromatic carboxylic acids; diglycidyl dimeric acid; diglycidyl oxalate; diglycidyl malate; diglycidyl succinate; diglycidyl glutarate; diglycidyl adipate; and (co)polymers (degree of polymerization, for example, 2 to 10) of (meth)acrylates; and glycidyl esters of aliphatic or alicyclic carboxylic acids.

[0124] The aforementioned glycidylamine is not particularly limited, but preferably is an aromatic amine having 6 or more carbon atoms and having two or more active hydrogen atoms, or an alicyclic or heterocyclic amine having 5 or more carbon atoms and having two or more active hydrogen atoms. Examples include N,N-diglycidylaniline, N,N-diglycidyltoluidine, N,N,N',N'-tetraglycidyldiaminodiphenylmethane, N,N,N',N'-tetraglycidyldiaminodiphenyl sulfone, and N,N,N',N'-tetraglycidyldiaminodiphenylmethane. Glycidylamines of aromatic amines such as tetraglycidyldiaminodiphenylmethane and N,N,O-triglycidylaminophenol; glycidylamines of aliphatic amines such as N,N,N',N'-tetraglycidylphenyldimethyldiamine and N,N,N',N'-tetraglycidylhexamethylenediamine; hydrogenated compounds of N,N,N',N'-tetraglycidylphenyldimethyldiamine and glycidylamines of alicyclic amines such as N,N,N',N'-tetraglycidylcyclohexanediamine; and glycidylamines of heterocyclic amines such as triglycidylmelamine.

[0125] The aforementioned chain-like aliphatic epoxides are not particularly limited, but chain-like aliphatic epoxides with 6 or more carbon atoms and a divalent or higher valence are preferred. Examples include epoxy-oxidized (poly)aliphatic dienes (e.g., epoxy-oxidized butadiene (Mw260-2,500) with an epoxy equivalent of 130 to 1,000) and epoxy-oxidized oils (epoxy-oxidized soybean oil (Mw130-2,500)).

[0126] The alicyclic epoxides described above are not particularly limited, but alicyclic epoxides with 6 or more carbon atoms, Mw 2,500 or less, and 2 or more epoxy groups are preferred. Examples include vinylcyclohexene dioxide, limonene dioxide, dicyclopentadiene dioxide, bis(2,3-epoxycyclopentyl) ether, ethylene glycol diepoxydicyclopentyl ether, bis(3,4-epoxy-6-methylcyclohexylmethyl) adipate, and bis(3,4-epoxy-6-methylcyclohexylmethyl) butylamine. Additionally, nucleohydrogenates of the epoxides of phenol described above are also included.

[0127] The urethane-modified epoxy compound having urethane bonds in the above structure is not particularly limited, and examples include, for instance, the reaction product of polyether urethane oligomers (Mw 200 to 2,500, for example, isocyanate-terminated urethane prepolymers obtained by reacting polyether diol with diisocyanate) and glycidyl ether.

[0128] (B) Isocyanate compounds

[0129] The isocyanate compound used as a chain extender in this invention is not particularly limited, and isocyanate compounds described, for example, in International Publication No. 2014 / 157375 may be used.

[0130] The isocyanate compound can be either a monofunctional isocyanate compound or a polyfunctional isocyanate compound, with polyfunctional isocyanate compounds being preferred. From the perspective of the sterilization durability, bending durability, and surface smoothness of the flexible endoscope tube, the polyfunctional isocyanate compound preferably has 2 or 3 functions (the number of isocyanate groups per molecule), more preferably 3.

[0131] The molecular weight of the isocyanate compound is preferably 100 or more, more preferably 150 or more. When the isocyanate compound has a molecular weight distribution, the weight-average molecular weight of the isocyanate compound is preferably 150 to 10,000, more preferably 200 to 10,000, and even more preferably 300 to 5,000.

[0132] Specific examples of monofunctional isocyanate compounds include butyl isocyanate, isopropyl isocyanate, 2-chloroethyl isocyanate, phenyl isocyanate, p-bromophenyl isocyanate, m-chlorophenyl isocyanate, o-chlorophenyl isocyanate, p-chlorophenyl isocyanate, 2,5-dichlorophenyl isocyanate, 3,4-dichlorophenyl isocyanate, 2,6-dimethylphenyl isocyanate, o-fluorophenyl isocyanate, p-fluorophenyl isocyanate, m-tolyl isocyanate, p-tolyl isocyanate, o-trifluoromethylphenyl isocyanate, m-trifluoromethylphenyl isocyanate, and benzyl isocyanate.

[0133] Specific examples of polyfunctional isocyanate compounds include hexamethylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,5-naphthalene diisocyanate, diphenylmethane-4,4'-diisocyanate, 2,2-dimethyldiphenylmethane-4,4'-diisocyanate, benzyltoluidine diisocyanate, isophorone diisocyanate, phenyl dimethyl diisocyanate, and 1,3-bis(isocyanate methyl) Cyclohexane, 1,3-bis(isocyanate-methyl)benzene, terephthalic diisocyanate, 1,3,6-hexamethylene triisocyanate, bicycloheptane triisocyanate, tri-(3-isocyanate-4-methylphenyl)isocyanurate and tri-(6-isocyanate-hexyl)isocyanurate (synonym: 1,3,5-tris(6-isocyanate-hexyl-1-yl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione).

[0134] Alternatively, compounds containing terminal isocyanate groups obtained by reacting the aforementioned polyfunctional isocyanate compounds with active hydrogen compounds may also be used. Examples of such compounds include addition reactants with terminal isocyanate groups obtained by reacting toluene diisocyanate with trimethylolpropane, and addition reactants with terminal isocyanate groups obtained by reacting toluene diisocyanate with pentaerythritol.

[0135] (C) Amine compounds

[0136] The amine compound used as a chain extender in this invention is not particularly limited, and amine compounds described in, for example, Japanese Patent Application Publication No. 2008-545606 and Japanese Patent Application Publication No. 2018-182199 may be used.

[0137] The amino group in an amine compound can be either an unsubstituted amino group or a monosubstituted amino group, with a nonsubstituted amino group being preferred. Hereinafter, amine compounds having a nonsubstituted amino group will be referred to as "primary amine compounds," and compounds having a monosubstituted amino group will be referred to as "secondary amine compounds." Specifically, amine compounds having both nonsubstituted and monosubstituted amino groups are classified as primary amine compounds.

[0138] From the perspective of the sterilization durability, bending durability and surface smoothness of the flexible tube for endoscopes, the functional number of the amine compound (the number of amino groups in one molecule) is preferably 2 to 4, more preferably 3 or 4, and even more preferably 4.

[0139] The molecular weight of the amine compound is preferably 50 or more, more preferably 150 or more. When the amine compound has a molecular weight distribution, the weight-average molecular weight of the amine compound is preferably 200 to 10,000, more preferably 300 to 8,000.

[0140] As amine compounds, amine compounds having a ring structure are preferred, especially alicyclic amine compounds (amine compounds having an alicyclic ring) and aromatic amine compounds (amine compounds having at least one of an aromatic hydrocarbon ring and an aromatic heterocycle), and more preferably aromatic amine compounds. Furthermore, amine compounds having alicyclic rings and aromatic rings (aromatic hydrocarbon rings and aromatic heterocycles) are classified as aromatic amine compounds.

[0141] Amine compounds can have multiple ring structures within a molecule, and these ring structures can be the same or different.

[0142] Cyclohexylamine is a specific example of an alicyclic primary amine compound (an amine compound having an alicyclic and unsubstituted amino group).

[0143] N-methylcyclohexylamine is a specific example of an alicyclic secondary amine compound (an amine compound having an alicyclic ring and a monosubstituted amino group).

[0144] Specific examples of aromatic primary amine compounds (amine compounds having an aromatic ring and a non-substituted amino group) include diaminodiphenyl ether, xylenediamine (preferably p-xylenediamine), diaminobenzene, diaminotoluene, methylenediphenylamine, dimethyldiaminobiphenyl, bis(trifluoromethyl)diaminobiphenyl, diaminobenzophenone, diaminobenzoylaniline, bis(aminophenyl)fluorene, bis(aminophenoxy)benzene, bis(aminophenoxy)biphenyl, dicarboxylated diaminodiphenylmethane, diaminoresorcinol, dihydroxybenzidine, diaminobenzidine, 4,4'-diaminodiphenylmethane Alkane, 1,3,5-triaminophenoxybenzene, 2,2'-dimethylbenzidine, tris(4-aminophenyl)amine, 2,7-diaminofluorene, tetra(4-aminophenyl)methane, 2,4'-diaminodiphenylmethane, (o-tolyl)biguanide, melamine (1,3,5-triazine-2,4,6-triamine), cyanuric acid diamide, melamine, melamine, 5-thiazolylamine, 2-aminobenzothiazole, N,N',N”-tris(4-aminophenyl)-1,3,5-triazine-2,4,6-triamine and 2,4-diamino-6-phenyl-1,3,5-triazine.

[0145] Specific examples of aromatic secondary amine compounds (amine compounds having an aromatic ring and a monosubstituted amino group) include 1,9-diaminofluorene, dibenzylamine, N,N'-di-isopropyl-p-phenylenediamine, N,N'-di-sec-butyl-p-phenylenediamine, N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine, N,N'-bis(1-ethyl-3-methylpentyl)-p-phenylenediamine, and N,N'-bis(1-methyl N,N'-dicyclohexyl-p-phenylenediamine, N,N'-diphenyl-p-phenylenediamine, N,N'-bis(2-naphthyl)-p-phenylenediamine, N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, N-(1-methylheptyl)-N'-phenyl-p-phenylenediamine, N-cyclohexyl-N'-phenyl-p-phenylenediamine, 4-(p-toluene) (Sulfoyl)diphenylamine, diphenylamine (which may have alkyl groups having 1 to 8 carbon atoms), 4-isopropoxydiphenylamine, N-phenyl-1-naphthylamine (which may have a tert-octyl group), N-(4-tert-octylphenyl)-1-naphthylamine, N-phenyl-2-naphthylamine, octylated diphenylamine (e.g., p,p'-di-tert-octyldiphenylamine), 4-n-butylaminophenol, 4-butyrylaminophenol, 4-nonanoylamino Benzylphenol, 4-dodecanoylaminophenol, 4-octadecanoylaminophenol, bis(4-methoxyphenyl)amine, 1,2-bis[(2-methylphenyl)-amino]ethane, 1,2-bis(phenylamino)propane, bis[4-(1′,3′-dimethylbutyl)phenyl]amine, 2,3-dihydro-3,3-dimethyl-4H-1,4-benzothiazine and phenothiazine (which may have alkyl groups having 1 to 8 carbon atoms).

[0146] In this invention, from the perspective of the sterilization durability, bending durability and surface smoothness of the flexible tube for endoscopes, aromatic primary amine compounds are preferably used as (C) amine compounds.

[0147] (D) Oxazoline compounds

[0148] In this invention, the oxazoline compound used as a chain extender is not particularly limited, and oxazoline compounds described in, for example, Japanese Patent Application Publication No. 2020-56006 and Japanese Patent Application Publication No. 2016-4978 may be used.

[0149] The oxazoline compound can be either a monofunctional oxazoline compound or a polyfunctional oxazoline compound, preferably a polyfunctional oxazoline compound. The number of functions (the number of oxazoline groups in one molecule) of the polyfunctional oxazoline compound is preferably 2 to 100, more preferably 2 to 50, and even more preferably 2 to 20.

[0150] The molecular weight of the oxazoline compound is preferably 100 or more, more preferably 200 or more. When the oxazoline compound has a molecular weight distribution, that is, when the oxazoline compound is a high molecular weight oxazoline compound, the weight-average molecular weight of the oxazoline compound is preferably 200 to 500,000, more preferably 500 to 500,000, more preferably 5,000 to 500,000, and even more preferably 10,000 to 200,000.

[0151] Examples of oxazoline compounds include bisoxazoline compounds and high molecular weight oxazoline compounds (i.e., polymers containing oxazoline groups, such as oxazoline-containing polystyrene, oxazoline-containing acrylic polymers, and oxazoline-containing styrene-(meth)acrylic acid copolymers). From the perspective of the sterilization durability, bending durability, and surface smoothness of the flexible tube for endoscopes, high molecular weight oxazoline compounds are preferred.

[0152] The oxazoline content of the high molecular weight oxazoline compound is not particularly limited, but is preferably 0.05 to 1.5 mmol / g, more preferably 0.1 to 1.0 mmol / g.

[0153] Examples of bisoxazoline compounds include 2,2'-bis(2-oxazoline), 2,2'-bis(4-methyl-2-oxazoline), 2,2'-bis(4,4-dimethyl-2-oxazoline), 2,2'-bis(4-ethyl-2-oxazoline), 2,2'-bis(4,4'-diethyl-2-oxazoline), 2,2'-bis(4-propyl-2-oxazoline), and 2,2'-bis(4-butyl-2-oxazoline). 2,2'-Bis(4-hexyl-2-oxazoline), 2,2'-Bis(4-phenyl-2-oxazoline), 2,2'-Bis(4-cyclohexyl-2-oxazoline), 2,2'-Bis(4-benzyl-2-oxazoline), 2,2'-p-phenylenebis(2-oxazoline), 2,2'-m-phenylenebis(2-oxazoline) (also known as 2,2'-(1,3-phenylene)bis(2-oxazoline)), 2,2'-o-phenylenebis(2-oxazoline) 2,2'-p-phenylenebis(4-methyl-2-oxazoline), 2,2'-p-phenylenebis(4,4-dimethyl-2-oxazoline), 2,2'-m-phenylenebis(4-methyl-2-oxazoline), 2,2'-m-phenylenebis(4,4-dimethyl-2-oxazoline), 2,2'-ethylenebis(2-oxazoline), 2,2'-tetramethylenebis(2-oxazoline), 2,2'-hexamethylenebis(2-oxazoline) 2,2'-Oxazoline, 2,2'-Octamethylenebis(2-oxazoline), 2,2'-Decamethylenebis(2-oxazoline), 2,2'-Ethylenebis(4-methyl-2-oxazoline), 2,2'-Tetramethylenebis(4,4-dimethyl-2-oxazoline), 2,2'-9,9'-Diphenoxyethanebis(2-oxazoline), 2,2'-Cyclohexylbis(2-oxazoline), and 2,2'-Diphenylenebis(2-oxazoline).

[0154] As a specific example of a high molecular weight oxazoline compound, the EPOCROS series manufactured by Nippon Shokubai Chemical Industry Co., Ltd. can be cited (e.g., EPOCROS K2010E, EPOCROS K2020E, EPOCROS K2030E, EPOCROS WS500, EPOCROS WS700, EPOCROS RPS-1005, all of which are trade names).

[0155] (E) Carbodiimide compounds with a molecular weight of less than 3,000

[0156] In this invention, carbodiimide compounds with a molecular weight of less than 3,000 (hereinafter also referred to as "carbodiimide compounds") used as chain extenders are not particularly limited, and carbodiimide compounds with a molecular weight of less than 3,000 as described in, for example, Japanese Patent Application Publication No. 2019-9263 and Japanese Patent Application Publication No. 2016-182685 may be used.

[0157] Furthermore, in the case of carbodiimide compounds having a molecular weight distribution, "molecular weight" refers to the weight-average molecular weight.

[0158] The molecular weight of the carbodiimide compound is preferably 150 or more, more preferably 200 or more. When the carbodiimide compound has a molecular weight distribution, the weight-average molecular weight is preferably 200 to 3,000, more preferably 500 to 2,000.

[0159] The carbodiimide compound can be either a monofunctional carbodiimide compound or a polyfunctional carbodiimide compound. The number of functions (the number of carbodiimide groups per molecule) of the carbodiimide compound is preferably 1 to 6, more preferably 1 to 3, and even more preferably 1.

[0160] The structure of the carbodiimide compound is not particularly limited and can be either chain-like or cyclic. However, carbodiimide compounds with cyclic structures are preferred from the perspectives of sterilization durability, bending durability, and surface smoothness of the flexible tube for endoscopes.

[0161] "Carbodiimide compounds with cyclic structures" refers to compounds that have a ring containing a carbodiimide group as a ring component, that is, compounds that have a ring (carbodiimide ring) with nitrogen atoms constituting the carbodiimide group and carbon atoms as ring-forming atoms.

[0162] The carbodiimide ring can consist of one or more carbodiimide groups, but one is preferred.

[0163] The carbodiimide ring is preferably a 4- to 16-membered ring, more preferably a 6- to 12-membered ring. Examples of the constituent atoms of the carbodiimide ring other than the carbodiimide group include carbon atoms, oxygen atoms, nitrogen atoms, and sulfur atoms.

[0164] Specific examples of monofunctional carbodiimide compounds include dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, tert-butylisopropylcarbodiimide, diphenylcarbodiimide, di-tert-butylcarbodiimide, di-β-naphthylcarbodiimide, N,N'-di-2,6-diisopropylphenylcarbodiimide, and compounds having a carbodiimide ring (with one carbodiimide group constituting the ring).

[0165] Specific examples of multifunctional carbodiimide compounds include polycarbodiimide compounds, i.e., polymers having carbodiimide groups in repeating units, wherein the degree of polymerization of such polymers is 2 or more, preferably 4 or more. On the other hand, the degree of polymerization is preferably 40 or less, more preferably 30 or less.

[0166] In addition, as specific examples of multifunctional carbodiimide compounds, compounds having two or more carbodiimide rings (the number of carbodiimide groups constituting the ring is 1) and compounds having one carbodiimide ring (the number of carbodiimide groups constituting the ring is 2 or more) can be listed.

[0167] Specific carbodiimide compounds that can be obtained industrially include, for example, CARBODILITEHMV-8CA (Nisshin Boshoku), CARBODILITE LA-1 (Nisshin Boshoku), STABAXOL I (Rhein Chemicals), STABAXOL P (Rhein Chemicals), STABAXOL P100 (Rhein Chemicals), STABAXOL P400 (Rhein Chemicals), STABILIZER9000 (Raschig Chemi), and CARBOSISTA TCC-NP (Teijin). (All are trade names.)

[0168] Furthermore, carbodiimide compounds having a cyclic structure can be prepared by, for example, the method described in International Publication No. 2011 / 093478. Additionally, polycarbodiimide compounds can be prepared by, for example, the methods described in U.S. Patent No. 2,941,956, Japanese Patent Publication No. 47-33279, J. Org. Chem. Vol. 28, pp. 2069-2075 (1963), and Chemical Review 1981, Vol. 81, No. 4, pp. 619-621.

[0169] Organic diisocyanates, which are raw materials for the manufacture of polycarbodiimide compounds, include, for example, aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, and mixtures thereof. Specifically, examples include 1,5-naphthalene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-toluene diisocyanate, and 2,6-phenylene diisocyanate. - Toluene diisocyanate, mixtures of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate, hexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, phenyl diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, methylcyclohexane diisocyanate, tetramethylphenyl diisocyanate, 2,6-diisopropylphenyl isocyanate, and 1,3,5-triisopropylphenyl-2,4-diisocyanate, etc.

[0170] (F) acid anhydride

[0171] In this invention, the carboxylic anhydride (anhydride derived from carboxylic acid) used as a chain extender is not particularly limited and can be either a chain carboxylic anhydride or a cyclic carboxylic anhydride, preferably a cyclic carboxylic anhydride.

[0172] The number of carboxylic anhydride groups is not particularly limited, but is preferably 1 to 3, and more preferably 2. That is, carboxylic anhydride (dicarboxylic anhydride), tetracarboxylic dianhydride and hexacarboxylic trihydride are preferred, and tetracarboxylic dianhydride is more preferred from the perspective of sterilization durability, bending durability and surface smoothness of the flexible tube for endoscopes.

[0173] The molecular weight of the carboxylic anhydride is not particularly limited, but is preferably 150 to 600, more preferably 180 to 400.

[0174] As a carboxylic anhydride (an anhydride derived from carboxylic acids), a carboxylic anhydride as described in, for example, Japanese Patent Application Publication No. 2016-37538 may be used.

[0175] Specific examples of carboxylic anhydrides (dicarboxylic anhydrides) include 4-ethynylphthalic anhydride (abbreviated as 4-EPA), 4-phenylethynylphthalic anhydride, maleic anhydride, citraconic anhydride, itaconic anhydride, allyl nadic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, cyclohexene-1,2-dicarboxylic anhydride, exo-3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride, and allyl succinic anhydride, etc.

[0176] Specific examples of tetracarboxylic dianhydrides include 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA), pyromellitic dianhydride (PMDA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 2,2',3,3'-benzophenone tetracarboxylic dianhydride, 2,3,3',4'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride, 2,2',3,3'-diphenylsulfone tetracarboxylic dianhydride, 2,3,3',4'-diphenylsulfone tetracarboxylic dianhydride, and 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride. Abbreviations: ODPA, 2,2',3,3'-diphenyl ether tetracarboxylic dianhydride, 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride, 2,2-[bis(3,4-dicarboxyphenyl)]hexafluoropropane dianhydride, ethylene glycol bis(dehydrated trimellitate), 4,4'-[(isopropylidene)bis(p-phenyleneoxy)]diphthalic dianhydride, cyclobutane tetracarboxylic dianhydride, methylcyclobutane tetracarboxylic dianhydride, cyclopentane tetracarboxylic dianhydride, 1,2,4,5-cyclohexane tetracarboxylic dianhydride, ethane tetracarboxylic dianhydride, butane tetracarboxylic dianhydride, and 3,3',4,4'-dicyclohexyl tetracarboxylic dianhydride.

[0177] As a specific example of a hexacarboxylic acid trihydride, benzenehexacarboxylic acid 1,2:3,4:5,6-carboxylic acid trihydride can be cited.

[0178] From the perspective of the sterilization durability, bending durability and surface smoothness of the flexible tube for endoscopes, at least one of (B) isocyanate compound, (C) amine compound, (D) oxazoline compound, (E) carbodiimide compound with a molecular weight of less than 3,000 and (F) carboxylic anhydride is preferably used as a chain extender, and more preferably at least one of (D) oxazoline compound, (E) carbodiimide compound with a molecular weight of less than 3,000 and (F) carboxylic anhydride is used.

[0179] In these combinations of chain extenders, the preferred configurations of each chain extender are as described above. That is, in these combinations, combinations of the preferred configurations of each chain extender are further preferred.

[0180] In this invention, chain extenders can be used alone or in combination of two or more.

[0181] The preparation of chain extenders of polyesters with naphthalene structures can be carried out using typical reaction conditions between polymers and chain extenders. For example, Japanese Patent Application Publication No. 2014-188217 can be consulted. Specifically, for example, the chain extender can be prepared by melt-mixing a mixture containing a polyester with a naphthalene structure and a chain extender, thereby reacting the polyester with the chain extender. This melt-mixing can be carried out, for example, using a mixer (such as a twin-screw mixer) at a heating temperature of 150°C to 300°C. Furthermore, a catalyst can be used as needed to prepare the chain extender of the polyester with a naphthalene structure.

[0182] The amount of chain extender used in the preparation of chain extenders of polyesters having a naphthalene structure is not particularly limited. In a total of 100 parts by weight of polyester having a naphthalene structure and chain extender, it is preferably 0.05 parts by weight or more and 3.0 parts by weight or less, more preferably 0.1 parts by weight or more and 2.0 parts by weight or less, and even more preferably 0.2 parts by weight or more and 1.5 parts by weight or less.

[0183] The coating layer may appropriately contain various commonly used additives without impairing the effects of the present invention. Examples of such additives include heat stabilizers, inorganic fillers, impact modifiers, plasticizers, lubricants, metallic soaps, lightfastness agents, and colorants. The content of the above-mentioned additives in the coating layer can also be appropriately adjusted. Such additives can be derived from the polyester chain extender having a naphthalene structure used, or they can be added separately from the polyester chain extender having a naphthalene structure.

[0184] (Middle layer)

[0185] To improve the adhesion between the flexible tube substrate and the coating layer, an intermediate layer such as an adhesive layer or a primer layer can be provided between them. As an example of such an adhesive layer, a layer formed from a composition of a polymer such as polyurethane and a polyisocyanate compound can be cited. As an example of a primer layer, a silane coupling agent can be cited. Furthermore, the thickness of the intermediate layer is not particularly limited and can be, for example, 0.1 to 1.0 mm.

[0186] (Topcoat)

[0187] In the flexible tube of the present invention, a topcoat (not shown) may be provided on the outer periphery of the coating layer 15 as needed. The material of the topcoat is not particularly limited, and urethane coatings, acrylic coatings, fluoropolymer coatings, silicone coatings, epoxy coatings, polyester coatings, etc. can be used.

[0188] The main purpose of using a topcoat is to protect or polish the surface of the flexible tube, impart lubrication, and provide chemical resistance. Therefore, a topcoat with a high elastic modulus, a smooth surface, and excellent chemical resistance is preferred.

[0189] <Manufacturing Method of Flexible Tubes>

[0190] The manufacture of the flexible endoscope tube of the present invention includes a coating layer formation step. This coating layer formation step includes: forming a coating layer on the outer periphery of the flexible tube substrate using a coating layer forming material, said coating layer forming material comprising a component from a polyester having a naphthalene structure, and at least one chain extender selected from (A) an epoxy compound, (B) an isocyanate compound, (C) an amine compound, (D) an oxazoline compound, (E) a carbodiimide compound with a molecular weight less than 3,000, and (F) a carboxylic anhydride. The formation of the coating layer itself using the coating layer forming material can be carried out by conventional methods, for example, by extruding the coating (forming temperature: 150–250°C) of the coating layer forming material. Furthermore, the coating layer forming material can be obtained, for example, by mixing the components for the coating layer forming material using a twin-screw extruder.

[0191] Endoscopic medical devices

[0192] The flexible tube of this invention can be widely used in endoscopic medical devices. It can also be applied to instruments, such as those with clamps or wires at the tip of an endoscope, or those with baskets or brushes. Furthermore, endoscopic medical devices, in a broader sense, include not only medical devices with an endoscope as their basic structure, but also remotely operated medical devices and other medical and diagnostic devices with flexible insertion parts that are inserted into the body for use.

[0193] The endoscopic medical device of the present invention has an endoscopic flexible tube of the present invention assembled in its insertion portion. That is, the method of manufacturing the endoscopic medical device of the present invention includes assembling the endoscopic flexible tube of the present invention, or the endoscopic flexible tube obtained by the method of manufacturing the endoscopic flexible tube of the present invention, into the insertion portion of the endoscopic medical device.

[0194] 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 can be used as a medical device in which a flexible endoscope tube is assembled and inserted into a body cavity for observation. Figure 1 In the example shown, the electronic endoscope 2 includes an insertion section 3 that is inserted into a body cavity, a main operating section 5 connected to the base of the insertion section 3, and a universal plug 6 connected to a processor or a light source. The insertion section 3 consists of a flexible tube 3a connected to the main operating section 5, a bend 3b connected to the flexible tube 3a, and a tip section 3c connected to the front end of the bend 3b and housing an imaging device (not shown) for intracavitary imaging. The flexible tube 3a, which occupies most of the length of the insertion section 3, is flexible almost along its entire length, and the portion inserted into the interior of a body cavity or similar structure is particularly flexible.

[0195] Flexible tube

[0196] The constituent material of the flexible tube substrate is not particularly limited, but a flexible tube substrate with metal as the constituent material is preferred.

[0197] like Figure 2 As shown, the flexible tube substrate 14 is preferably configured such that a tubular mesh 12 made of braided metal wire is covered on a spiral tube 11 formed by winding a metal strip 11a into a spiral shape on the innermost side, and tube heads 13 are respectively fitted at both ends. The metal constituting the flexible tube substrate 14 preferably has its surface subjected to passivation treatment to prevent corrosion. That is, the flexible tube substrate 14 preferably has a passivation film on its outer periphery. This passivation treatment can be carried out by common methods. For example, a passivation film can be formed on the metal surface by immersion in a solution containing a strong oxidizing agent such as nitric acid, heating in air (oxygen) or water (water vapor), or anodizing in a solution containing an oxidizing agent.

[0198] The metal constituting the flexible tube substrate 14 is preferably stainless steel. The surface of stainless steel is usually in a state where chromium and oxygen are bonded to form a passivation film. However, even when stainless steel is used as the constituent material of the flexible tube substrate 14, it is preferable to perform the above-described passivation treatment on the stainless steel in order to reliably form a more uniform passivation film across the entire stainless steel surface.

[0199] In this embodiment, the coating layer 15 is formed with a substantially uniform thickness along the length (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, 1.7 to 13.5 mm, preferably 3.0 to 8.0 mm. Furthermore, the outer diameter of the flexible tube substrate 14 is, for example, 1.6 to 12.5 mm, preferably 2.2 to 7.8 mm. Additionally, when the flexible tube of the present invention is used for insertion into a 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.

[0200] [Example]

[0201] The present invention will now be described in more detail by way of examples, but the present invention is not limited to these examples.

[0202] <Preparation of Coating Forming Materials>

[0203] The mixture prepared by setting the components listed in Tables 1-1 to 1-5 (hereinafter referred to as Table 1) to the proportions (parts by mass) listed in Table 1 is introduced into a twin-screw mixer (TECHNOVEL KZW15-30MG, trade name) with the barrel and die temperatures set at 220°C, and is mixed at a screw speed of 100 rpm. The molten strand discharged from the twin-screw mixer is cooled in a water bath and then cut into granules by a granulator to obtain a coating material.

[0204] <Preparation of Flexible Tube Substrate>

[0205] Reference Figure 2 The flexible tube substrate used in the embodiments and comparative examples is described.

[0206] A spiral tube 11 is formed using stainless steel metal strips 11a, and a flexible tube substrate in the form of the spiral tube 11 is prepared to be covered with a tubular mesh 12 incorporating stainless steel fibers. The flexible tube substrate is 80 cm in length and 12 mm in diameter. A passivation layer is formed on the surface of the stainless steel flexible tube substrate through an annealing treatment (heat treatment) during the formation of the spiral tube and the tubular mesh.

[0207] <Formation of Adhesive Layer>

[0208] A solution for forming an adhesive is prepared by mixing 10 parts by mass of polyester polyurethane ("N-2304" (trade name) manufactured by Nippon Polyurethane Industry Co., Ltd.), 1 part by mass of polyisocyanate ("CORONATE L" (trade name) manufactured by Nippon Polyurethane Industry Co., Ltd.), and 20 parts by mass of methyl ethyl ketone. The solution is uniformly coated on the outer periphery of the stainless-steel flexible tube substrate and dried at room temperature for 2 hours. Then, it is heat-treated at 150 °C for 2 hours to prepare a flexible tube substrate having an adhesive layer on its outer periphery (resin-coated surface). The thickness of the adhesive layer is 0.3 mm.

[0209] <Formation of the coating layer>

[0210] The above-prepared coating layer forming material (forming temperature: 220 °C) is extruded and coated on the outer periphery of the flexible tube substrate provided with the adhesive layer to manufacture a flexible tube for an endoscope having a coating layer. The thickness of the coating layer is 0.4 mm.

[0211] [Test Example 1 (Surface smoothness)]

[0212] The coating layer is peeled off from the above-manufactured flexible tube for an endoscope, and a test piece with a size of 2 cm × 2 cm is cut out and placed on a smooth metal plate. Using a surface gloss meter ("VG-2000" (trade name), a variable-angle gloss meter manufactured by Nippon Denshoku Industries Co., Ltd.), light is irradiated onto the surface of the test piece at an incident angle of 60°, and the reflectance is measured. The evaluation is carried out according to the following evaluation criteria. Passing this test requires a result of "C" or above. In addition, the greater the reflectance, the better the surface smoothness of the flexible tube for an endoscope.

[0213] <Evaluation criteria>

[0214] A: 90% or more

[0215] B: 80% or more and less than 90%

[0216] C: 70% or more and less than 80%

[0217] D: Less than 70%

[0218] [Test Example 2 (Flexural durability)]

[0219] One end of the above-manufactured flexible tube for an endoscope (length 80 cm) is designated as end a, and the other end is designated as end b. After making the center of the length direction of the flexible tube for an endoscope contact (touch) the apex of a fixed pulley, the flexible tube is bent along the periphery of the pulley (curvature radius 5 cm) to form a U shape. In this bent U shape, the semi-circular part (15.7 cm) around the pulley is in contact with the flexible tube. Hold end a and b and alternately pull end a and b as described below.

[0220] (1) Pull end a to keep the flexible tube in contact with the half circumference of the pulley, while moving the end of end a by 20cm.

[0221] (2) Pull end b to keep the flexible tube in contact with the half circumference of the pulley, while moving the end of end b by 40cm.

[0222] (3) Pull end a to keep the flexible tube in contact with the half circumference of the pulley, while moving the end of end a by 20cm to return to the initial U-shaped state of (1).

[0223] (1) to (3) are considered as one cycle. The number of cycles when peeling occurs between the flexible tube substrate and the coating or cracking occurs in the coating is evaluated according to the following evaluation criteria. "C" or above is considered as passing this test.

[0224] <Evaluation Criteria>

[0225] AA: 50,000 times or more

[0226] A: More than 10,000 times but less than 50,000 times

[0227] B: More than 2,000 times but less than 10,000 times

[0228] C: More than 100 times but less than 2,000 times

[0229] D: Less than 100 times

[0230] [Experiment 3 (Sterilization Durability)]

[0231] Following the same procedure as in Example 1, a test piece measuring 1 cm × 10 cm was cut. This test piece was placed in the flow path of an ozone water generator (trade name: EcoDesign "OWM-10L10P"), and ozone water with an ozone concentration of 5 ppm was allowed to flow at a rate of 1 L / min for 8 hours. Afterward, the piece was rinsed with distilled water and dried at 23°C × 50% RH (relative humidity) for 24 hours. The dried test piece was then subjected to a tensile test using a TENSILON universal testing machine (trade name: RTF-1210, A&D Corporation), and evaluated against the following evaluation criteria (100% elongation means elongation to twice its original size). A score of "C" or higher indicates a passing grade for this test.

[0232] <Evaluation Criteria>

[0233] A: It did not break even when the elongation reached 300%.

[0234] B: It did not break even when the elongation reached 200%, but broke before the elongation reached 300%.

[0235] C: It did not break even when the elongation reached 100%, but broke before the elongation reached 200%.

[0236] D: It breaks before the elongation reaches 100%.

[0237] [Table 1-1]

[0238]

[0239] [Table 1-2]

[0240]

[0241] [Table 1-3]

[0242]

[0243] [Table 1-4]

[0244]

[0245] [Table 1-5]

[0246]

[0247] Example: Implementation

[0248] Comparison: Example

[0249] <Explanation of terms in the table>

[0250] [(T) Polyester with naphthalene structure]

[0251] (T-1) Polyester elastomer containing polybutylene naphthalate in the structural unit (PELPRENE EN-5000, manufactured by Toyobo Co., Ltd., trade name, weight average molecular weight 119,000)

[0252] (T-2) Polyester elastomer containing polybutylene naphthalate in the structural unit (PELPRENE EN-1000, manufactured by Toyobo Co., Ltd., trade name, weight average molecular weight 131,000)

[0253] [(S) Other polymers]

[0254] (S-1) Polyester elastomer containing polybutylene terephthalate in the structural unit (PELPRENE P-280B manufactured by Toyobo Co., Ltd., weight average molecular weight 128,000).

[0255] (S-2) Ether-based polyurethane elastomer (MIRACTRAN E574PNAT, manufactured by Nippon Polyurethane Co., Ltd., trade name, weight average molecular weight 145,000)

[0256] (S-3) Polyamide elastomer (Arkema "PEBAX 7233" (trade name), weight average molecular weight 48,000)

[0257] [(A) Epoxy compounds]

[0258] (A-1) Bisphenol A diglycidyl ether (manufactured by Mitsubishi Chemical Corporation, "jER828" (trade name), difunctional, molecular weight 340)

[0259] (A-2) Glyceryl triglycidyl ether (DENACOL EX-313, manufactured by Nagase Chertex Co., Ltd., a trifunctional company with a molecular weight of 260)

[0260] (A-3) Tetraglycidyldiaminodiphenylmethane (Sumitomo Chemical Co., Ltd. "SUMI-EPOXY ELM-434" (trade name), tetrafunctional, molecular weight 423)

[0261] [(B) Isocyanate compounds]

[0262] (B-1) p-Tolyl isocyanate (a reagent manufactured by Tokyo Chemical Co., Ltd., monofunctional, molecular weight 133)

[0263] (B-2)1,3-Bis(isocyanate methyl)benzene (Mitsui Chemicals Co., Ltd. "TAKENATE500" (trade name), difunctional, molecular weight 188)

[0264] (B-3)1,3,5-Tris(6-isocyanate-hexyl-1-yl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione (manufactured by Nippon Polyurethane Co., Ltd., "CORONATE HX" (trade name), trifunctional, molecular weight 505)

[0265] [(C)Amine compounds]

[0266] (C-1)4,4'-Diaminodiphenylmethane (a reagent manufactured by Tokyo Chemical Industry Co., Ltd., difunctional, molecular weight 198)

[0267] (C-2)1,3,5-Triazine-2,4,6-Triamine (Reagent manufactured by Fujifilm and Koh Genuine Chemicals Co., Ltd., trifunctional, molecular weight 126)

[0268] (C-3) Tetra(4-aminophenyl)methane (a reagent manufactured by Tokyo Chemical Industry Co., Ltd., tetrafunctional, molecular weight 381)

[0269] [(D)Oxazoline compounds]

[0270] (D-1)2,2'-(1,3-phenylene)bis(2-oxazoline) (Mitsuku Pharmaceutical Co., Ltd., “1,3-BPO” (trade name), difunctional, molecular weight 216)

[0271] (D-2) High molecular weight oxazoline (EPOCROS RPS-1005 manufactured by Nippon Shokubai Co., Ltd. (trade name), weight average molecular weight 160,000, oxazoline group content 0.27 mmol / g)

[0272] [(E) Carbodiimide compounds with a molecular weight below 3,000]

[0273] (E-1) Low molecular weight monocarbodiimide (STABAXOL I, manufactured by Rhein Chemical Company, molecular weight 362)

[0274] (E-2) Cyclic carbodiimide (Teijin Corporation's "CARBOSISTA TCC-NP" (trade name), molecular weight 516)

[0275] [(F)carboxylic anhydride]

[0276] (F-1)4-ethynylphthalic anhydride (a reagent manufactured by Tokyo Chemical Co., Ltd., monofunctional, molecular weight 172)

[0277] (F-2)1,2,4,5-Cyclohexanetetracarboxylic dianhydride (Tokyo Chemical Co., Ltd. reagent, difunctional, molecular weight 224)

[0278] (F-3)3,3',4,4'-Diphenyl ether tetracarboxylic acid dianhydride (a reagent manufactured by Tokyo Chemical Industry Co., Ltd., difunctional, molecular weight 294)

[0279] [Chain extender used in the comparative example]

[0280] (e-3) Polycarbodiimide (STABAXOL P100, manufactured by Rhein Chemical Company, trade name, weight average molecular weight 15,000)

[0281] Based on the results in Table 1, the following can be observed.

[0282] The coating of Comparative Example 1 contains a polyester having a naphthalene structure, but is not a chain extender as defined in this invention. The flexible tube of Comparative Example 1 failed in terms of bending durability and sterilization durability.

[0283] The coating of Comparative Example 2 comprises a polyester chain extender with a naphthalene structure prepared using polycarbodiimide with a weight average molecular weight of 15,000. The surface smoothness and sterilization durability of the flexible tube of Comparative Example 2 are unsatisfactory.

[0284] Furthermore, based on the results of Comparative Examples 3 to 20, it can be seen that even when the chain extender specified in this invention is used, the sterilization durability is at least unsatisfactory when the polyester chain does not have a naphthalene structure.

[0285] In contrast, the coatings of Examples 1 to 25 contain a chain extender of a polyester with a naphthalene structure as specified in this invention, and their surface smoothness, bending durability, and sterilization durability are all satisfactory.

[0286] Based on the comparisons of Examples 10 and 11, Examples 12 and 13, and Examples 14, 15, and 16, it is evident that the properties of flexible endoscope tubes can be further improved by using high-molecular-weight oxazoline compounds, carbodiimide compounds with cyclic structures, and tetracarboxylic dianhydrides as chain extenders. It can be considered that the use of these chain extenders can suppress the gelation of polyesters with naphthalene structures, which is one reason for the improved properties.

[0287] 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.

[0288] This application claims priority based on Japanese Patent Application No. 2020-111754, filed on June 29, 2020, the contents of which are incorporated herein by reference and incorporated herein by reference as part of the description.

[0289] Symbol Explanation

[0290] 2. Electronic endoscope (Endoscope)

[0291] 3. Insertion section

[0292] 3a Flexible tube

[0293] 3b Corner

[0294] 3C top part

[0295] 5 Main Operating Unit

[0296] 6. Universal Plug Rope

[0297] 11. Spiral tube

[0298] 11a Metal strip

[0299] 12 cylindrical mesh

[0300] 13 Pipe head

[0301] 14 Flexible tube substrate

[0302] 15. Covering layer

Claims

1. A flexible tube for an endoscope, comprising: Flexible tubular flexible tube substrate, and The coating covering the outer periphery of the flexible tube substrate. in, The coating layer comprises a chain extender of a polyester having a naphthalene structure. The chain extender comprises: The constituent elements of at least one chain extender selected from (B) trifunctional isocyanate compounds, (C) tetrafunctional amine compounds, (D) oxazoline compounds, (E) carbodiimide compounds with a molecular weight less than 3,000, and (F) carboxylic anhydrides, or the constituent elements of a chain extender composed of a combination of a trifunctional epoxide compound and a trifunctional amine compound; and Components derived from polyesters with naphthalene structures, The coating may or may not contain additives selected from the group consisting of heat stabilizers, inorganic fillers, impact modifiers, plasticizers, lubricants, metallic soaps, and colorants.

2. The flexible endoscope tube according to claim 1, wherein, The chain extender of the polyester having a naphthalene structure comprises components derived from the (D) oxazoline compound. The constituents of the (D) oxazoline compound include constituents from high molecular weight oxazoline compounds.

3. The flexible endoscope tube according to claim 1 or 2, wherein, The chain extender of the polyester having a naphthalene structure comprises components derived from the carbodiimide compound with a molecular weight less than 3,000 in the (E) group. The constituent components of the carbodiimide compounds with a molecular weight of less than 3,000 in (E) include constituent components of carbodiimide compounds having a cyclic structure.

4. The flexible endoscope tube according to claim 1 or 2, wherein, The chain extender of the polyester having a naphthalene structure includes components derived from the (F) carboxylic anhydride. The constituent components of the (F) carboxylic anhydride include those derived from tetracarboxylic dianhydride.

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

6. A method for manufacturing a flexible tube for an endoscope, wherein, include: A coating is formed on at least the outer periphery of a flexible tubular substrate using a coating forming material. The coating forming material comprises: (B) at least one chain extender selected from the following: (C) a trifunctional isocyanate compound, (D) a tetrafunctional amine compound, (E) a carbodiimide compound with a molecular weight of less than 3,000, and (F) a carboxylic anhydride, or a chain extender derived from a combination of a trifunctional epoxy compound and a trifunctional amine compound. and Polyesters with naphthalene structure, The coating forming material may or may not contain additives selected from the group consisting of heat stabilizers, inorganic fillers, impact modifiers, plasticizers, lubricants, metallic soaps, and colorants.

7. A method for manufacturing an endoscopic medical device, wherein, include: The process of obtaining a flexible tube for endoscope by the manufacturing method of the flexible tube for endoscope according to claim 6; as well as The process of assembling the obtained endoscope into the insertion part of an endoscopic medical device using a flexible tube.

8. A method for manufacturing an endoscopic medical device, wherein, include: The flexible endoscope tube according to any one of claims 1 to 4 is assembled into the insertion part of the endoscopic medical device.

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