Flexible tubes for endoscopes, endoscopic medical devices and their manufacturing methods

Abstract

This invention provides a flexible endoscope tube, an endoscopic medical device incorporating the flexible endoscope tube, and a method for manufacturing the same. The flexible endoscope tube exhibits excellent resilience, maintaining a tight seal between the flexible tube substrate and its covering polymer coating even after prolonged and repeated exposure to a hot atmosphere. Furthermore, the seal between the flexible tube substrate and the polymer coating is not easily compromised even after repeated disinfection treatment with hydrogen peroxide. The flexible endoscope tube comprises a flexible tube substrate made of metal, a siloxane compound layer on the flexible tube substrate, a primer layer on the siloxane compound layer, and a polymer coating layer on the primer layer. The siloxane compound has hydroxyl groups, and the polymer coating layer contains at least one compound selected from polyamide, polyester, polyurethane, and polyolefin on the side in contact with the primer layer.

Description

Technical Field

[0001] This invention relates to a flexible tube for endoscopy, 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, esophagus, etc. Because it is inserted into the body, it is desirable to avoid damaging organs and causing pain or discomfort to the patient. Based on these requirements, the flexible tube constituting the insertion part (the structural part inserted into the body cavity) of the endoscope is a spiral tube formed by winding a soft, flexible metal strip into a helix. Furthermore, the spiral tube is coated with a soft polymer, which, if necessary, is further coated to prevent irritation or damage to the inner surfaces of the esophagus, digestive tract, body cavities, etc.

[0003] To ensure smooth movement of the flexible tube within the body, high resilience is required. By improving the resilience of the flexible tube, it easily returns to a straight shape after passing through a bend within the body, thus reducing the burden on the patient during examination. As a technique to meet this requirement, for example, Patent Document 1 describes a method where a primer is applied to the surface of a metal core material (flexible tube substrate), followed by a molded outer skin layer; the primer can be a silane coupling agent, a titanate coupling agent, an aluminum coupling agent, or a zirconium coupling agent. According to Patent Document 1, this flexible tube for endoscopy exhibits excellent resilience.

[0004] Previous technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2010-035923 Summary of the Invention

[0007] The technical problem to be solved by the invention

[0008] On the other hand, to improve the operability and durability of endoscopes, it is crucial to enhance the adhesion between the flexible tube substrate and the polymer coating covering it. If this adhesion is insufficient, wrinkling, lifting, cracking, and peeling can easily occur on the polymer coating due to the bending of the flexible tube during insertion. Furthermore, twisting can easily occur on the polymer coating when rotating the flexible tube after insertion. If wrinkling, lifting, cracking, peeling, or twisting occurs on the polymer coating, the surface of the inserted flexible tube may snag on surrounding tissues, causing pain to the patient.

[0009] Each time an endoscope is used, it is repeatedly exposed to a warm environment generated by the light source built into the endoscope. Furthermore, each time an endoscope is used, it undergoes disinfection or sterilization with medication, again resulting in repeated exposure to a warm environment of approximately 60°C. The inventors have discovered that the flexible endoscope tube described in Patent Document 1 tends to experience a decrease in its seal when repeatedly exposed to a warm environment. Therefore, it is also required that the flexible endoscope tube exhibit excellent long-term thermal durability (the characteristic that the seal does not easily decrease even when repeatedly exposed to a warm environment).

[0010] It was also learned that the flexible endoscope tube described in Patent Document 1 also tends to have decreased sealing performance due to repeated disinfection treatment with hydrogen peroxide water, which has strong oxidizing power. This is believed to be because hydrogen peroxide oxidizes and decomposes the primer components, and is particularly attributed to the activation of the hydrogen peroxide through the surface of the metal substrate.

[0011] Therefore, the object of the present invention is to provide a flexible endoscope tube and an endoscopic medical device incorporating the flexible endoscope tube, wherein the flexible endoscope tube exhibits excellent resilience and maintains sufficient adhesion between the flexible tube substrate and the polymer coating layer even after prolonged and repeated exposure to a hot atmosphere. Furthermore, even after repeated disinfection treatment with hydrogen peroxide water, the adhesion between the flexible tube substrate and the polymer coating layer is not easily diminished. In addition, the object of the present invention is to provide a method for manufacturing the aforementioned flexible endoscope tube and a method for manufacturing the aforementioned endoscopic medical device.

[0012] means for solving technical problems

[0013] In view of the aforementioned problems, the inventors conducted repeated studies on the formation of polymer coatings on flexible tubes for endoscopes. They discovered that by forming a layer on the surface of a flexible tube substrate made of a metallic material using a hydroxyl-containing siloxane compound, forming a primer layer on this siloxane compound layer, and then using a specific type of polymer as the constituent material of the polymer coating layer adjacent to the primer layer, the aforementioned problems can be solved. This invention was completed based on further repeated studies of these insights.

[0014] The above-mentioned problems of the present invention are solved by the following solution.

[0015] <1>

[0016] A flexible tube for endoscopes comprises a flexible tube substrate made of metal, a siloxane compound layer on the flexible tube substrate, a primer layer on the siloxane compound layer, and a polymer coating layer on the primer layer.

[0017] The above-mentioned siloxane compounds have hydroxyl groups.

[0018] The polymer coating layer comprises at least one compound selected from polyamide, polyester, polyurethane and polyolefin on the side in contact with the primer layer.

[0019] <2>

[0020] according to <1> The flexible tube for the endoscope, wherein,

[0021] The aforementioned siloxane compounds include organosiloxane compounds.

[0022] <3>

[0023] according to <1> or <2> The flexible tube for the endoscope, wherein,

[0024] The aforementioned primer layer contains at least one of silane coupling agent, titanium coupling agent, zirconium coupling agent, and aluminum coupling agent.

[0025] <4>

[0026] according to <1> ~ <3> The flexible tube for the endoscope described in any one of the following statements, wherein,

[0027] The aforementioned primer layer contains a silane coupling agent.

[0028] <5>

[0029] according to <1> ~ <4> The flexible tube for the endoscope described in any one of the following statements, wherein,

[0030] The aforementioned primer layer contains an aminosilane coupling agent.

[0031] <6>

[0032] according to <1> ~ <5> The flexible tube for the endoscope described in any one of the following statements, wherein,

[0033] The metal constituting the flexible tube substrate is stainless steel.

[0034] <7>

[0035] according to <1> ~ <6> The flexible tube for the endoscope described in any one of the following statements, wherein,

[0036] The metal constituting the above-mentioned flexible tube substrate has a passivation film on its surface.

[0037] <8>

[0038] according to <1> ~ <7> The flexible tube for the endoscope described in any one of the following statements, wherein,

[0039] The polymer coating is a single-layer or multi-layer structure, and the layer in contact with the primer layer contains at least one compound selected from polyamide, polyester, polyurethane and polyolefin.

[0040] <9>

[0041] according to <1> ~ <8> The flexible tube for the endoscope described in any one of the following statements, wherein,

[0042] The polymer coating has a double-layer structure, and the ratio of the thickness of the inner and outer layers of the double-layer structure varies gradually along the axial direction of the flexible tube substrate.

[0043] <10>

[0044] according to <1> ~ <9> The flexible tube for the endoscope described in any one of the following statements, wherein,

[0045] The thickness ratio of the inner layer to the outer layer is 95:5 to 60:40 at one end of the flexible tube for the endoscope, and 5:95 to 40:60 at the other end.

[0046] <11>

[0047] An endoscopic medical device, which has <1> ~ <10> The flexible tube for endoscopes as described in any one of these descriptions.

[0048] <12>

[0049] A method for manufacturing a flexible tube for endoscopes includes depositing a siloxane compound layer on a flexible tube substrate made of metal, depositing a primer layer on the siloxane compound layer, and depositing a polymer coating layer on the primer layer.

[0050] Siloxane compounds have hydroxyl groups,

[0051] The polymer coating layer contains at least one compound selected from polyamide, polyester, polyurethane and polyolefin on the side in contact with the primer layer.

[0052] <13>

[0053] A method for manufacturing an endoscopic medical device, comprising: passing through... <12> The endoscope flexible tube obtained by the manufacturing method of the described endoscope flexible tube is assembled into the insertion part of the endoscope type medical device.

[0054] <14>

[0055] A method for manufacturing an endoscopic medical device, comprising: <1> ~ <10> The endoscope is assembled into the insertion part of the endoscopic medical device using a flexible tube as described in any one of the above methods.

[0056] In this specification, when there are multiple substituents or linking groups (hereinafter referred to as substituents, etc.) indicated by specific symbols, or when multiple substituents, etc., are specified simultaneously or alternatively, it means that the individual substituents, etc., may be the same as or different from each other. Furthermore, even without specific explanation, when multiple substituents, etc., are adjacent, it means that they may also be linked together or cyclically contracted to form a ring.

[0057] In this specification, the term "substituent" (and the same applies to linking groups) that is not explicitly stated as substituted or unsubstituted means that the group may have any substituents to achieve the desired effect. This meaning also applies to compounds that are not explicitly stated as substituted or unsubstituted.

[0058] In this specification, when the number of carbon atoms of a certain group is specified, that number of carbon atoms refers to the total number of carbon atoms of the group as a whole. That is, when the group is in the form of further having substituents, it refers to the total number of carbon atoms including the substituents.

[0059] Invention Effects

[0060] The flexible tube for endoscopes of the present invention has excellent resilience. Even when repeatedly exposed to a hot atmosphere for a long time, it can maintain the tightness of the flexible tube substrate and the polymer coating covering it. In addition, even when repeatedly subjected to disinfection treatment with hydrogen peroxide water, the tightness of the flexible tube substrate and the polymer coating is not easily reduced.

[0061] The flexible tube, which serves as the insertable structural part of the endoscopic medical device of the present invention, exhibits excellent resilience. Even when repeatedly exposed to a hot atmosphere over a long period, it can maintain sufficient adhesion between the flexible tube substrate and the polymer coating covering it. Furthermore, even after repeated disinfection treatment with hydrogen peroxide water, the adhesion between the flexible tube substrate and the polymer coating is not prone to decrease. Therefore, the endoscopic medical device of the present invention has excellent durability, further reducing the burden on the patient during use.

[0062] According to the manufacturing method of the flexible tube for endoscope of the present invention, a flexible tube for endoscope can be obtained with excellent resilience. Even when repeatedly exposed to a hot atmosphere for a long time, the adhesion between the flexible tube substrate and the polymer coating covering it can be fully maintained. In addition, even when repeatedly subjected to disinfection treatment with hydrogen peroxide water, the adhesion between the flexible tube substrate and the polymer coating is not easily reduced.

[0063] According to the manufacturing method of the endoscopic medical device of the present invention, the flexible tube constituting the device can be characterized by excellent resilience, maintaining sufficient adhesion between the flexible tube substrate and the polymer coating layer even after prolonged and repeated exposure to a hot atmosphere, and exhibiting minimal degradation of adhesion even after repeated disinfection treatment with hydrogen peroxide water. Therefore, the manufacturing method of the endoscopic medical device of the present invention provides an endoscopic medical device with excellent durability and significantly reduced burden on the patient during use. Attached Figure Description

[0064] Figure 1 This is an external view showing the structure of one embodiment of an electronic endoscope.

[0065] Figure 2 This is a partial cross-sectional view showing the structure of one embodiment of a flexible tube for endoscopy.

[0066] Figure 3 This is a block diagram illustrating the structure of one embodiment of a manufacturing apparatus for a flexible tube for an endoscope.

[0067] Figure 4 It is Figure 3 A sectional view obtained by cutting along the BB line. Detailed Implementation

[0068] Taking an electronic endoscope as an example, a preferred embodiment of an endoscopic medical device assembled with the flexible endoscopic tube of the present invention (hereinafter, the flexible endoscopic tube is sometimes simply referred to as a "flexible tube") will be described. The electronic endoscope is used as a medical device for observing the body by inserting the flexible tube into body cavities, the digestive tract, the esophagus, etc. Figure 1 In the example shown, the electronic endoscope 2 includes an insertion part 3 for insertion 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 and a light source. 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 3c connected to the tip of the bend 3b and housing an in-body imaging device (not shown). The flexible tube 3a, occupying most of the length of the insertion part 3, is flexible almost entirely, especially the portion inserted into a body cavity or other internal space, which is made even more flexible. Figure 1 In the middle, the curved corner 3b side has a soft structure, while the main body operating part 5 side has a hard structure.

[0069] [Flexible tube for endoscopes]

[0070] The flexible tube for endoscopes of the present invention comprises a flexible tube substrate made of metal, a siloxane compound layer on the flexible tube substrate, a primer layer on the siloxane compound layer, and a polymer coating layer on the primer layer.

[0071] The above-mentioned siloxane compounds have at least one of hydrolyzable groups and hydroxyl groups.

[0072] Furthermore, the polymer coating layer contains at least one compound selected from polyamide, polyester, polyurethane, and polyolefin on the side in contact with the primer layer. Specifically, the flexible endoscope tube sequentially comprises a flexible tube substrate made of metal, a siloxane compound layer, a primer layer, and a polymer coating layer. The siloxane compound has hydroxyl groups, and the polymer coating layer contains at least one compound selected from polyamide, polyester, polyurethane, and polyolefin on the side in contact with the primer layer.

[0073] In addition, Figure 2 The diagram does not show the siloxane compound layer and primer layer.

[0074] The flexible endoscope tube of the present invention exhibits excellent resilience. Even after prolonged and repeated exposure to a hot atmosphere, it maintains sufficient adhesion between the flexible tube substrate and the polymer coating covering it. Furthermore, even after repeated disinfection treatment with hydrogen peroxide water, the adhesion between the flexible tube substrate and the polymer coating is not easily reduced. The reason for this is not yet clear, but it is speculated to be due to the following factors: the siloxane compound layer itself exhibits higher resistance to hydrogen peroxide; the number of covalent bonds (e.g., ether bonds) between the primer layer and the flexible tube substrate layer, etc.

[0075] <Flexible tube substrate>

[0076] Flexible tubes have a flexible tube substrate made of metal as the innermost layer.

[0077] like Figure 2 As shown, the flexible tube substrate 14 is preferably configured as follows: a cylindrical mesh 12 formed by covering a spiral tube 11, which is formed by spirally winding a metal strip 11a around the innermost side, is covered with a braided metal wire, and tube ends 13 are respectively fitted to both ends. To prevent corrosion, the surface of the metal constituting the flexible tube substrate 14 is preferably subjected to passivation treatment. That is, the flexible tube substrate 14 preferably has a passivation film (e.g., a metal oxide film) on its outer periphery. This passivation treatment can be performed 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.

[0078] 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 combine to form a passivation film. However, even when stainless steel is used as the constituent material of the flexible tube substrate 14, in order to more reliably form a more uniform passivation film across the entire stainless steel surface, it is preferable to apply the above-described passivation treatment to the stainless steel.

[0079] <Siloxane compound layer>

[0080] The siloxane compound contained in the siloxane compound layer is a compound having a siloxane bond (a repeating structure of [-Si-O]), for example, an oligomer or polymer obtained by hydrolyzing and condensing silane compounds having hydrolyzable groups together. Therefore, the siloxane compound has hydroxyl groups. The silane compound can be either an inorganic silane compound or an organosilane compound, preferably an organosilane compound. That is, the siloxane compound is preferably an organosiloxane compound.

[0081] Examples of hydrolyzable groups include alkoxy (alkyloxy), alkenyloxy, acyloxy, aminooxy, oxime, and amide groups, with alkoxy being preferred.

[0082] The alkyl group in the alkoxy group can be straight-chain, branched, or cyclic. The alkyl group preferably has 1 to 30 carbon atoms, more preferably 1 to 20, even more preferably 1 to 10, and even more preferably 1 or 2. Specific examples of alkyl groups include methyl, ethyl, isopropyl, butyl, and cyclopentyl.

[0083] The alkenyl group in the alkenyloxy group can be any of straight-chain, branched, or cyclic. The alkenyl group preferably has 2 to 30 carbon atoms, more preferably 2 to 20, and even more preferably 2 to 10.

[0084] Examples of organosilane compounds include tetraalkoxysilane compounds, trialkoxysilane compounds, and dialkoxysilane compounds.

[0085] The aforementioned tetraalkoxysilanes are not particularly limited, and examples include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, and tetrabutoxysilane.

[0086] Trialkoxysilane compounds are not particularly limited, and examples include methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, and phenyltriethoxysilane.

[0087] Dialkoxysilane compounds are not particularly limited, and examples include dimethyldimethoxysilane and dimethyldiethoxysilane.

[0088] Siloxane compounds preferably do not have organic groups other than methyl and ethyl groups.

[0089] The weight-average molecular weight of the siloxane compound is not particularly limited, for example, preferably 100 to 2000, more preferably 150 to 500.

[0090] The weight-average molecular weight or number-average molecular weight of the compounds described in this application is determined by the following procedure.

[0091] Weight-average molecular weight or number-average molecular weight can be measured as the molecular weight of polystyrene by gel permeation chromatography (GPC).

[0092] Specifically, the GPC device HLC-8220 (trade name, manufactured by Tosoh Corporation) was used, with tetrahydrofuran as the eluent, and the chromatographic column was G3000HXL+G2000HXL (both trade names, manufactured by Tosoh Corporation), with a flow rate of 1 mL / min at 23°C, and detection was performed using RI.

[0093] Examples of siloxane compounds that can be used in the present invention include those used in the examples described later, but the present invention is not limited thereto.

[0094] The flexible tube of the present invention is defined as a form in which a siloxane compound layer reacts with at least one of a flexible tube substrate and a primer layer. For example, the siloxane compound layer may be in the form of a siloxane compound having hydroxyl groups reacting with the constituent metals of the primer layer or the flexible tube substrate, or reacting with groups on the surface of the polymer coating layer.

[0095] The content of siloxane compounds in the siloxane compound layer is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more. The siloxane compound layer can be a layer composed of siloxane compounds.

[0096] The content of organosiloxanes in the siloxane compound layer is not particularly limited; for example, it can be set to 80% by mass or more, preferably 90% by mass or more, or even 100% by mass.

[0097] Provided that the effects of the present invention are not compromised, the siloxane compound layer may also contain components other than siloxane compounds. Examples of such components include: alkanol metals other than the coupling agents described later, adhesive resins, and stabilizers (surfactants and antioxidants).

[0098] The average thickness of the siloxane compound layer is not particularly limited. From the viewpoint of the flexible tube's resilience, thermal durability, and hydrogen peroxide water resistance, 5 to 400 nm is preferred, 15 to 300 nm is more preferred, 25 to 150 nm is even more preferred, and 40 to 100 nm is even more preferred.

[0099] <Primer layer>

[0100] Considering the resilience, thermal durability, and hydrogen peroxide resistance of the flexible tube, the primer layer constituting the flexible tube of the present invention preferably includes at least one of silane coupling agent, titanium coupling agent, zirconium coupling agent, and aluminum coupling agent.

[0101] Furthermore, the silane coupling agent preferably does not have siloxane bonds, and preferably has organic groups other than methyl, ethyl, methoxy and ethoxy groups (e.g., vinyl, propyl, anhydride, epoxy).

[0102] As silane coupling agents, titanium coupling agents, zirconium coupling agents, and aluminum coupling agents used in this invention, common silane coupling agents, titanium coupling agents, zirconium coupling agents, and aluminum coupling agents applicable to the primer layer of flexible tubes for endoscopes can be widely used. In this invention, considering the resilience, thermal durability, and hydrogen peroxide water resistance of the flexible tube, the primer layer preferably contains a silane coupling agent, more preferably an aminosilane coupling agent (preferably a silane coupling agent having at least one of unsubstituted amino and monosubstituted amino groups). Specific examples of silane coupling agents, titanium coupling agents, zirconium coupling agents, and aluminum coupling agents used in the embodiments described later can be given, but this invention is not limited thereto.

[0103] The total content of silane coupling agent, titanium coupling agent, zirconium coupling agent, and aluminum coupling agent in the aforementioned primer layer is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more. Furthermore, the aforementioned primer layer may be a layer composed of at least one of silane coupling agent, titanium coupling agent, zirconium coupling agent, and aluminum coupling agent.

[0104] The molecular weight of the silane coupling agent, titanium coupling agent, zirconium coupling agent and aluminum coupling agent used in the present invention is not particularly limited, for example, preferably 100 to 2000, more preferably 200 to 500.

[0105] Alternatively, polymeric silane coupling agents can also be used.

[0106] When the primer layer contains an aminosilane coupling agent, the content of the aminosilane coupling agent in the silane coupling agent constituting the primer layer is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more.

[0107] Provided that the effect of the present invention is not compromised, the primer layer may contain components other than silane coupling agents, titanium coupling agents, zirconium coupling agents and aluminum coupling agents. Examples of such components include, for example, alkanolic metals, adhesive resins, surfactants and antioxidants, etc., in addition to the coupling agents mentioned above.

[0108] In this invention, "the primer layer comprises at least one of silane coupling agents, titanium coupling agents, zirconium coupling agents, and aluminum coupling agents" means that it includes at least one of silane coupling agents, titanium coupling agents, zirconium coupling agents, and aluminum coupling agents in a state after reacting with a siloxane compound layer or flexible tube substrate, and in a state after reacting with a polymer coating layer. That is, the silane coupling agents, titanium coupling agents, zirconium coupling agents, and aluminum coupling agents are in a state where at least a portion is hydrolyzed and hydroxyl groups are exposed, and they can react with the constituent metals of the siloxane compound layer or flexible tube substrate, or react with the groups on the surface of the polymer coating layer.

[0109] The primer layer described above is significantly thinner than a typical adhesive layer (in other words, the concept of thickness can be ignored). That is, the primer layer differs from the adhesive layer used for bonding flexible tube substrates to polymer coatings, which requires a certain thickness and flexibility.

[0110] <Polymer Coating>

[0111] The flexible tube of the present invention has a polymer coating layer on the outer periphery of a flexible tube substrate having a siloxane compound layer and a primer layer in sequence.

[0112] exist Figure 2 In this form, an upper coating 16 containing fluorine or the like, which contributes to chemical resistance, is applied to the outer surface of the polymer coating 15. Figure 2 In the figure, only one layer of the spiral tube 11 is shown, but it can also be constructed by overlapping two or more layers coaxially. In addition, in order to clearly illustrate the layer structure, the polymer coating layer 15 and the upper coating layer 16 are drawn to be thicker than the diameter of the flexible tube substrate 14 in the figure.

[0113] In this invention, a polymer coating layer covers the outer peripheral surface of a flexible tube substrate having the aforementioned siloxane compound layer and primer layer. Figure 2 In this form, the polymer coating layer 15 is a double-layer structure formed by stacking an inner layer 17 covering the entire circumference of the flexible tube substrate 14 around its axis and an outer layer 18 covering the entire circumference of the inner layer 17 around its axis. Typically, the inner layer 17 is made of a soft polymer and the outer layer 18 is made of a hard polymer, but the present invention is not limited to these forms.

[0114] In this invention, as described below, when the polymer coating layer is a multilayer structure with two or more layers, at least the innermost layer (the layer in contact with the primer layer) contains at least one compound selected from polyamide, polyester, polyurethane, and polyolefin. Furthermore, in this invention, when the polymer coating layer is a single layer, the single-layer polymer coating layer contains at least one compound selected from polyamide, polyester, polyurethane, and polyolefin. That is, in this invention, the polymer coating layer contains at least one compound selected from polyamide, polyester, polyurethane, and polyolefin at least on the side in contact with the primer layer, preferably on the side in contact with the primer layer.

[0115] (Polyamide)

[0116] As a polyamide, common polyamides that can be widely used as polymer coatings for flexible tubes used in endoscopes are widely applicable. Examples include crystalline polyamides, amorphous polyamides, and polyamide elastomers.

[0117] There are no particular limitations on crystalline polyamides; examples include aliphatic polyamides and aromatic polyamides.

[0118] Examples of aliphatic polyamides include: poly(ε-hexamethylene adipamide) (polyamide 6), polytetramethylene adipamide (polyamide 46), polyhexamethylene adipamide (polyamide 66), poly(hexamethylene adipamide) / polyhexamethylene adipamide copolymer (polyamide 6 / 66), poly(undecanamide) (polyamide 11), poly(hexamethylene adipamide) / poly(undecanamide) copolymer (polyamide 6 / 11), poly(dodecanoamide) (polyamide 12), poly(hexamethylene adipamide) / poly(dodecanoamide) copolymer (polyamide 6 / 12), poly(hexamethylene sebacate) (polyamide 610), poly(decamethylene sebacate) (polyamide 1010), poly(hexamethylene lauramide) (polyamide 612), poly(decamethylene lauramide) (polyamide 1012), poly(undecanamide) (polyamide 116), and mixtures or copolymers thereof.

[0119] 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. Amide / polyhexamethylene isophthalamide copolymer (polyamide 66 / 6I), polytrimethylhexamethylene terephthalamide (polyamide TMDT), polybis(4-aminocyclohexyl)methane lauramide (polyamide PACM12), polybis(3-methyl-4-aminocyclohexyl)methane lauramide (nylon dimethyl PACM12), polyadipamide isophthalamide (polyamide MXD6), polydemoethylene terephthalamide (polyamide 10T), polyundemethylene terephthalamide (polyamide 11T), and mixtures or copolymers thereof.

[0120] Examples of amorphous polyamides include: condensation polymers of isophthalic acid / terephthalic acid / 1,6-hexanediamine / bis(3-methyl-4-aminocyclohexyl)methane, condensation polymers of terephthalic acid / 2,2,4-trimethyl-1,6-hexanediamine / 2,4,4-trimethyl-1,6-hexanediamine, condensation polymers of isophthalic acid / bis(3-methyl-4-aminocyclohexyl)methane / ω-laurolactam, and condensation polymers of isophthalic acid / terephthalic acid / 1,6-hexanediamine. Polymers, 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, condensation polymers of isophthalic acid / bis(3-methyl-4-aminocyclohexyl)methane / ω-laurolactam, condensation polymers of isophthalic acid / terephthalic acid / other diamine components, etc.

[0121] Examples of polyamide elastomers include elastomers with polyamide as the hard segment, often referred to as amide thermoplastic elastomers. Examples include multiblock copolymers with polyamide as the hard segment and polyether or polyester as the soft segment, and multiblock copolymers with polyamide as the hard segment and soft segments having both ether and ester bonds. Examples of hard segments include polyamides 6, 66, 610, 11, and 12. Examples of polyethers in the soft segment include polyethylene glycol, poly(oxytetramethylene) glycol, and poly(propylene oxide) glycol; examples of polyesters include polyethylene adipate and 1,4-butanediol adipate.

[0122] Examples of commercially available polyamides that can be used in this invention include: polyamide 11 (manufactured by Arkema, trade name "RILSAN BMN O"), polyamide 12 (manufactured by Cadena Lu-Evonik, trade name "DAIAMID L1940"), polyamide 1010 (manufactured by Cadena Lu-Evonik, trade name "VESTAMID TerraDS16"), polyamide 1012 (manufactured by Evonik, trade name "VESTAMID TerraDD16"), amorphous polyamide (manufactured by Cadena Lu-Evonik, trade name "TROGAMIDCX7323"), and polyamide elastomers (manufactured by Arkema, trade names "PEBAX 4533", "PEBAX 7233", and "PEBAXRnew80R53").

[0123] Polyamides can be used alone or in combination of two or more.

[0124] (Polyester)

[0125] As a polyester, common polyesters that can be widely used as polymer coatings for flexible tubes used in endoscopes are widely applicable. Examples include thermoplastic polyesters and polyester elastomers.

[0126] Examples of thermoplastic polyesters include polyester resins composed of dicarboxylic acid and diol components, and polyester resins composed of hydroxycarboxylic acid components.

[0127] Examples of dicarboxylic acid components include: terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-biphenyl dicarboxylic 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.

[0128] In addition, examples of diol components include: ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, cyclohexanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, polybutanediol, and ethylene oxide adducts of bisphenol A or bisphenol S.

[0129] Examples of hydroxycarboxylic acid components include: ε-caprolactone, lactic acid, and 4-hydroxybenzoic acid.

[0130] The thermoplastic polyester resin can be a homopolymer composed of the above-mentioned dicarboxylic acid components and diol components or a homopolymer composed of the above-mentioned hydroxycarboxylic acid components, or it can be a copolymer. Furthermore, it can also contain small amounts of trifunctional or higher-functional compounds such as trimellitic acid, pyromellitic acid, benzopyrene, trimethylolpropane, glycerol, and pentaerythritol.

[0131] Examples of polyester elastomers include elastomers with polyester hard segments, often referred to as ester thermoplastic elastomers. Examples of other elastomers include multiblock copolymers with crystalline polyester hard segments and polyether or polyester soft segments, and multiblock copolymers with crystalline polyester hard segments and soft segments having both ether and ester bonds.

[0132] Examples of hard segments include: polybutylene terephthalate and polyethylene terephthalate.

[0133] Examples of soft segments include: polyalkylene glycols such as polybutane glycol and polypropylene glycol, bisphenol A ethylene oxide adducts, bisphenol A propylene oxide adducts, and polyesters such as polycaprolactone.

[0134] As a polyester elastomer, block copolymers consisting of a high-melting-point polyester segment (hard segment) and a low-melting-point polymer segment (soft segment) with a molecular weight of 400 to 6,000 can be used, such as those described in Japanese Patent Application Publication No. 11-92636.

[0135] Examples of commercially available polyesters used in this invention include: polyester elastomers (manufactured by Toyobo Corporation under the trade names "PELPRENE P-40B", "PELPRENE P-70B" and "PELPRENE S-3001", and manufactured by Mitsubishi Chemical Corporation under the trade name "PRIMALLOY B1942") and polybutylene terephthalate (manufactured by Mitsubishi Engineering Plastics Corporation under the trade name "NOVADURAN 5505S").

[0136] Polyester can be used alone or in combination of two or more types.

[0137] (Polyurethane)

[0138] As polyurethane, common polyurethanes that can be used as polymer coatings for flexible tubes in endoscopes can be widely employed. Polyurethanes of the form of carbonates, ethers, esters, or mixtures thereof can be used. Polyurethane elastomers are also preferred. Examples of polyurethane elastomers include block polymers, also known as urethane thermoplastic elastomers, which are block polymers with polyurethane hard segments and soft segments having ether, ester, or carbonate bonds, or mixtures thereof, and can be appropriately prepared according to the purpose. Examples include block polymers comprising hard segments composed of low-molecular-weight diols and diisocyanates, and soft segments composed of high-molecular-weight (long-chain) diols and diisocyanates.

[0139] Examples of high molecular weight (long-chain) diols include: polyether diols, polyester diols, and lactone-based polyester diols. Examples include: polypropylene glycol, polybutane oxide, poly(1,4-butanediol adipate), poly(ethylene glycol adipate-co-1,4-butanediol adipate), polycaprolactone diols, poly(1,6-hexanediol carbonate), and poly(1,6-hexanediol adipate-co-neopentyl adipate). The number average molecular weight of the high molecular weight (long-chain) diol is preferably 500–10,000.

[0140] As low-molecular-weight diols, short-chain diols such as ethylene glycol, propylene glycol, 1,4-butanediol, and bisphenol A can be used. The number-average molecular weight of the short-chain diols is preferably 48–500.

[0141] Examples of diisocyanate components mentioned above include: diphenylmethane diisocyanate, hexamethylene diisocyanate, benzyltoluidine diisocyanate, 1,5-naphthalene diisocyanate, isophorone diisocyanate, phthalic acid diisocyanate, etc.

[0142] As for the polyurethane elastomer involved in the above embodiments, reference can be made to, for example, the disclosure of Japanese Patent Application Publication No. 2005-015643.

[0143] Examples of commercially available polyurethanes that can be used in this invention include: PANDEX T-2185, T-2983N (manufactured by DIC Corporation), Miractran (manufactured by Miractran Corporation of Japan), Flasollan (manufactured by BASF Corporation of Japan), Resamine (manufactured by Dainisei Chemical Co., Ltd.), Pellethane (manufactured by Dow Chemical Co., Ltd.), IRON RUBBER (manufactured by NOK Corporation), MOBILON (manufactured by Nisshinbo Chemical Co., Ltd.), etc. Examples include: ISOPLAST (manufactured by Lubrizol Corporation), TECOFLEX (manufactured by Lubrizol Corporation), SUPERFLEX 830, 460, 870, 420 or 420NS (polyurethane manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), HYDRANAP-40F, WLS-202 or HW-140SF (polyurethane manufactured by DIC Corporation), OLESTER UD500 or UD350 (polyurethane manufactured by Mitsui Chemicals Co., Ltd.), and TAKELAC W-615, W-6010, W-6020, W-6061, W-405, W-5030, W-5661, W-512A-6, W-635 or WPB-6601 (manufactured by Mitsui Chemicals Co., Ltd.), etc.

[0144] Polyurethane can be used alone or in combination of two or more types.

[0145] (Polyolefins)

[0146] As polyolefins, common polyolefins that can be widely used as polymer coatings for flexible tubes used in endoscopes are examples of polyolefin resins or rubbers and olefin elastomers.

[0147] Examples of polyolefin resins or rubbers include homopolymers or copolymers of α-olefins with 2 to 20 carbon atoms, such as ethylene, propylene, 1-butene, 1-hexene, and 4-methyl-pentene. Other examples include copolymers of non-conjugated dienes with 2 to 20 carbon atoms, such as dicyclopentadiene, 1,4-hexadiene, cyclooctadiene, methylene norbornene, ethylidene norbornene, butadiene, and isoprene, with α-olefins. Furthermore, examples include ethylene-α-olefin copolymer rubbers, ethylene-α-olefin-non-conjugated diene copolymer rubbers, propylene-α-olefin copolymer rubbers, and butene-α-olefin copolymer rubbers. In addition, the following can also be used: ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid ester-(meth)acrylic acid copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl acetate-(meth)acrylic acid copolymer, ethylene-propylene-(meth)acrylic acid copolymer, ethylene-propylene-(meth)acrylic acid ester-(meth)acrylic acid copolymer, ethylene-maleic anhydride copolymer, ethylene-(meth)acrylic acid ester-maleic anhydride copolymer, ethylene-butene-maleic anhydride copolymer, ethylene-butene-(meth)acrylic acid copolymer, ethylene-butene-maleic anhydride-(meth)acrylic acid copolymer, propylene-butene-maleic anhydride copolymer, propylene-butene-(meth)acrylic acid copolymer, propylene-butene-maleic anhydride-(meth)acrylic acid copolymer, and ethylene-vinyl chloride copolymer, etc.

[0148] Examples of polyolefins that are olefin elastomers include: ethylene-propylene copolymers, ethylene-1-butene copolymers, ethylene-α-olefin copolymers, propylene-1-butene copolymers, propylene-α-olefin copolymers, 1-butene-α-olefin copolymers, propylene-1-butene-ethylene copolymers, propylene-α-olefin-ethylene copolymers, propylene-α-olefin-1-butene copolymers, 1-butene-α-olefin-ethylene copolymers, and polypropylene.

[0149] Examples of rubber components in olefin elastomers include: propylene rubber (PP), ethylene-propylene rubber (EPM) and ethylene-propylene-diene rubber (EPDM), polyisoprene, polybutadiene, chloroprene rubber, and isobutylene-isoprene copolymer.

[0150] Olefin elastomers may contain one or more polyolefin and rubber components.

[0151] Examples of commercially available polyolefins used in this invention include: SARLINK 3145D (trade name, manufactured by Toyobo Co., Ltd.) and ZELAS MC707 (trade name, manufactured by Mitsubishi Chemical Co., Ltd.).

[0152] Polyolefins can be used alone or in combination of two or more.

[0153] When the polymer coating layer is a single layer, the total content of compounds selected from polyamide, polyester, polyurethane, and polyolefin in the polymer coating layer, and when the polymer coating layer is multilayer, the total content of compounds selected from polyamide, polyester, polyurethane, and polyolefin in the innermost layer, is preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, and even more preferably 90% by mass or more. Furthermore, when the polymer coating layer is a single layer, it can be a layer composed of at least one compound selected from polyamide, polyester, polyurethane, and polyolefin; and when the polymer coating layer is multilayer, the innermost layer can be a layer composed of at least one compound selected from polyamide, polyester, polyurethane, and polyolefin.

[0154] When the polymer coating is a single layer, or when the innermost layer of the polymer coating is a multilayer layer, contains a polymer other than that selected from polyamide, polyester, polyurethane and polyolefin, the polymer is not particularly limited as long as it does not impair the effect of the present invention.

[0155] Furthermore, the polymer coating may appropriately contain various commonly used additives within a range that does not impair the effects of the present invention. Examples of such additives include, for instance, heat stabilizers, inorganic fillers, impact modifiers, plasticizers, lubricants, metallic soaps, lightfastness agents, and colorants. The content of the above-mentioned additives in the polymer coating can also be appropriately adjusted. Such additives may be derived from the polymer material used, or they may be added separately from the polymer.

[0156] When the polymer coating is multilayered, the layers other than the innermost layer preferably contain at least one compound selected from polyamide, polyester, polyurethane, and polyolefin. These polymers can be appropriately combined to form layers with desired properties.

[0157] The polymers used in the polymer coatings 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 particularly preferably a molecular weight of 30,000 to 300,000.

[0158] In this invention, unless otherwise specified, the molecular weight of the polymer constituting the polymer coating refers to the weight-average molecular weight. The weight-average molecular weight can be measured as the molecular weight converted from polystyrene by gel permeation chromatography (GPC).

[0159] like Figure 2 As shown, in this invention, the polymer coating 15 is preferably formed with a substantially uniform thickness along the longitudinal direction (axial direction) of the flexible tube substrate 14. The thickness of the polymer coating 15 is, for example, 0.2 mm to 1.0 mm. The outer diameter D of the flexible tube 3a is appropriately set according to the purpose, for example, 11 to 14 mm. Figure 2 In this design, the thicknesses of the inner layer 17 and the outer layer 18 are formed such that, along the axial direction of the flexible tube substrate 14, the thickness ratio of each layer 17 and 18 varies relative to the overall thickness of the polymer coating layer 15. Specifically, at one end 14a (top end side) of the flexible tube substrate 14 mounted on the bend 3b, the thickness of the inner layer 17 is greater than the thickness of the outer layer 18 relative to the total thickness of the polymer coating layer 15. Furthermore, from one end 14a toward the other end 14b (base end side) mounted on the main operating part 5, the thickness of the inner layer 17 gradually decreases, while at the other end 14b, the thickness of the outer layer 18 is greater than the thickness of the inner layer 17.

[0160] exist Figure 2 In the flexible tube 3a, the thickness ratio of the inner layer 17 is the largest at one end 14a, while the thickness ratio of the outer layer 18 is the largest at the other end 14b. The thickness ratio of the inner layer 17 to the outer layer 18 can be, for example, 9:1 at one end 14a and, for example, 1:9 at the other end 14b. By changing the thickness of the two layers, the thickness ratio of the inner layer 17 to the outer layer 18 is reversed from both ends 14a to 14b. This creates a difference in hardness between the one end 14a side and the other end 14b side, allowing the flexibility to vary axially by making one end 14a side softer and the other end 14b side harder. Preferably, the thickness ratio of the inner and outer layers at one end is 95:5 to 60:40 (inner layer:outer layer), and preferably the thickness ratio at the other end is 5:95 to 40:60 (inner layer:outer layer).

[0161] Furthermore, by setting the thickness ratio of the inner layer 17 to the outer layer 18 within the range of 95:5 to 5:95, the extrusion amount of the polymer on the thinner side can also be precisely controlled.

[0162] The soft and hard polymers used in the inner layer 17 and outer layer 18 preferably have a difference of 100% modulus values, which is an indicator of the hardness after molding, of 1 MPa or more, more preferably 3 MPa or more. The difference in melt viscosity at molding temperatures of 150°C to 300°C, which is an indicator of the fluidity of the polymer in the molten state, is preferably 2500 Pa·s or less. Thus, the polymer coating layer 15 composed of the inner layer 17 and outer layer 18 can ensure both good molding accuracy and the required hardness difference between the top and bottom sides.

[0163] <Top Coating>

[0164] In the flexible tube of the present invention, a coating 16 is disposed on the outer periphery of the polymer coating layer 15 as needed. The material of the coating is not particularly limited, and urethane coatings, acrylic coatings, fluoropolymer coatings, silicone coatings, epoxy coatings, polyester coatings, etc. can be used.

[0165] The main purpose of using a top coating is to protect or polish the surface of the flexible tube, impart lubrication, and provide chemical resistance. Therefore, a top coating with high elasticity, a smooth surface, and excellent chemical resistance is preferred.

[0166] [Manufacturing method of flexible tube]

[0167] <Formation of Siloxane Compound Layers>

[0168] The following are specific examples of methods for forming siloxane compound layers, but the present invention is not limited to these specific examples.

[0169] The siloxane compound layer can be formed on the flexible tube substrate (outer periphery) through the processes described in (i) and (ii) below.

[0170] (i) A silica composition is prepared by dehydration condensation reaction of an alkoxysilane compound.

[0171] (ii) After coating the flexible tube substrate with a silica composition, the silica composition is dried (or heated) to form a coating film, and then heated.

[0172] In step (i) above, the alkoxysilane compound is subjected to a dehydration condensation reaction in a composition containing an alkoxysilane compound, water and an organic solvent to obtain a silica composition.

[0173] For example, an alkoxysilane compound, an organic solvent, and water are mixed, and a catalyst (described later) is prepared as needed. The mixture is then stirred at, for example, 40–120°C for 10 minutes to 8 hours. An organic solvent (preferably the same as described above) is added to the resulting mixture, and the mixture is stirred at room temperature (e.g., 25–30°C) for approximately 10–90 minutes to prepare a homogeneous solution. The solution obtained in this manner is then diluted with an organic solvent (preferably a different organic solvent than described above).

[0174] In the silica composition, the total content of silane compounds (compounds containing silicon atoms) is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.5% by mass or more, and even more preferably 1% by mass or more. On the other hand, the total content of the above-mentioned silane compounds is preferably 70% by mass or less, more preferably 50% by mass or less, even more preferably 40% by mass or less, and even more preferably 20% by mass or less.

[0175] To make the siloxane compound layer porous, the silica composition may also contain surfactants.

[0176] As an organic solvent, it is preferable to use an organic solvent that can miscible with water as described above. That is, a water-soluble organic solvent is preferred. Examples include: monohydric alcohols with 1 to 5 carbon atoms such as methanol, ethanol, 1-propanol, 2-propanol, 2-methyl-1-propanol, 1-butanol, 2-butanol, tert-butanol, and 1-pentanol; dihydric alcohols with 1 to 4 carbon atoms such as glycerol and pentaerythritol; ethers or esters of the above alcohols such as methyl acetate, ethyl acetate, isobutyl acetate, diethylene glycol, ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, 2-ethoxyethanol, propylene glycol monomethyl ether, and propylene glycol methyl ether acetate; ketones such as acetone and methyl ethyl ketone; formamide, N-methylformamide, etc. Amide compounds such as N-ethylformamide, N,N-dimethylformamide, N,N-diethylformamide, N-methylacetamide, N-ethylacetamide, N,N-dimethylacetamide, N,N-diethylacetamide, N-methylpyrrolidone, N-formylmorpholine, N-acetylmorpholine, N-formylpiperidine, N-acetylpiperidine, N-formylpyrrolidine, N-acetylpyrrolidine, N,N'-diformylpiperazine, N,N'-diacetylpiperazine, etc.; lactone compounds such as γ-butyrolactone; ureas such as tetramethylurea and N,N'-dimethylimidazoline; and dimethyl sulfoxide, etc. Among these, alcohols are preferred, and monohydric alcohols are more preferred, in order to hydrolyze under more stable conditions compared to the contained alkoxysilane compounds.

[0177] Silica compositions typically contain a catalyst. The catalyst can be any substance that promotes the hydrolysis and dehydration condensation reactions of alkoxysilane compounds.

[0178] Examples include: hydrofluoric acid, phosphoric acid, boric acid, hydrochloric acid, nitric acid, sulfuric acid, formic acid, acetic acid, oxalic acid, maleic acid, methylmalonic acid, stearic acid, linoleic acid, benzoic acid, phthalic acid, citric acid, succinic acid, etc.; amine compounds such as ammonia, butylamine, dibutylamine, triethylamine, etc.; bases such as pyridine; Lewis acids such as aluminum acetylacetone complexes; etc.

[0179] In addition, metal chelate compounds can be cited as examples of catalysts. Examples of metals that can be used in such chelate compounds include titanium, aluminum, zirconium, tin, and antimony.

[0180] Within the scope of not impairing the effects of the present invention, the silica composition may also contain components other than the alkoxysilane compounds, organic solvents, surfactants, water, and catalysts mentioned above.

[0181] In step (ii) above, for example, the flexible tube substrate is immersed in the silica composition obtained in step (i) above, and then the flexible tube substrate is removed and dried to form a coating film. Next, it is heated at 80 to 400°C, thereby obtaining a flexible tube substrate having a siloxane compound layer.

[0182] Furthermore, when using commercially available siloxane compounds, it is possible to prepare a silica composition containing, for example, 0.01 to 3% by mass of a siloxane compound in the aforementioned organic solvent, and to perform the aforementioned step (ii) using this composition.

[0183] Before forming the siloxane compound layer, the flexible tube substrate is preferably pre-cleaned using an acid or alkali solution, an aqueous surfactant solution, or an organic solvent. Furthermore, it is preferable to further pre-clean with water or warm water after the above cleaning to reduce the amount of acid, alkali, surfactant, etc., on the substrate surface.

[0184] In this invention, to the extent that the effects of the invention are not compromised, a portion of the flexible tube substrate may be not covered by the siloxane compound layer (i.e., a portion of the siloxane compound layer may have voids).

[0185] <Formation of the primer layer>

[0186] In the manufacture of the flexible tube of the present invention, after forming a siloxane compound layer, a primer layer is formed on the siloxane compound layer. The primer layer can be formed by dissolving at least one of a silane coupling agent, a titanium coupling agent, a zirconium coupling agent, and an aluminum coupling agent in a solvent to prepare a coating solution, applying or spraying the coating solution onto the outer periphery of the flexible tube substrate, or immersing the flexible tube substrate in the coating solution, thereby forming a coating film at least on the outer periphery of the flexible tube substrate, and then drying the coating film by a common method (e.g., high-temperature drying at around 100°C).

[0187] As solvents for the coating solution, alcohol solvents such as methanol and ethanol; ketone solvents such as acetone and methyl ethyl ketone; ester solvents such as ethyl acetate; hydrocarbon solvents such as toluene, or mixtures of these solvents, can be used. Furthermore, to promote the hydrolysis of silane coupling agents, titanium coupling agents, zirconium coupling agents, and aluminum coupling agents, a mixture of these solvents with water or an acid catalyst such as acetic acid is preferred. Additionally, the coating solution can be prepared as acidic (e.g., pH 1–4 at 25°C) or alkaline (e.g., pH 9–11 at 25°C).

[0188] The content of silane coupling agent, titanium coupling agent, zirconium coupling agent and aluminum coupling agent in the coating solution is not particularly limited. For example, the total content can be set to 0.01 to 2% by mass, preferably 0.05% by mass or more and less than 1.5% by mass, and more preferably 0.1% by mass or more and less than 1.0% by mass.

[0189] The coating solution may contain surfactants, catalysts, etc., in addition to at least one of silane coupling agents, titanium coupling agents, zirconium coupling agents, and aluminum coupling agents, a solvent, and a pH adjuster. More preferably, the coating solution is composed of at least one of silane coupling agents, titanium coupling agents, zirconium coupling agents, and aluminum coupling agents, and a solvent.

[0190] In this invention, to the extent that the effects of this invention are not impaired, a portion of the siloxane compound layer may be uncovered by the primer layer (i.e., a portion of the primer layer may have voids).

[0191] <Formation of Polymer Coating>

[0192] The formation of the polymer coating will be explained using the case where the polymer coating has a double-layer structure as an example.

[0193] A flexible tube with a double-layer structure consisting of an inner layer and an outer layer can be obtained, for example, by melting and mixing a first polymer material (a polymer material comprising at least one compound selected from polyamide, polyester, polyurethane and polyolefin) constituting the inner layer and a second polymer material constituting the outer layer and extruding them around the flexible tube substrate after the primer layer has been formed, thereby coating the flexible tube substrate.

[0194] In addition, polymer coatings of one or more layers can also be obtained by appropriately modifying the layer structure, referring to the methods described below.

[0195] based on Figure 3 , Figure 4 For flexible tube 3a ( Figure 1 , Figure 2 An example of a method for forming a polymer coating 15 will be described. In this method, a continuous molding machine is used to form the polymer coating 15. The continuous molding machine 20 is preferably a molding machine composed of the following components: well-known extrusion sections 21 and 22, such as hoppers, screws 21a and 22a; a head 23 for coating the polymer coating 15 onto the outer peripheral surface of the flexible tube substrate 14; a cooling section 24; a conveying section 25 (feeding cylinder 28 and winding cylinder 29) for conveying the flexible tube substrate 31 to the head 23; and a control section 26 for controlling these components. The head 23 is preferably composed of a pipe joint 32, a die head 33, and a support body 34 for fixing and supporting these components. As an example of the configuration of the device described above, the one disclosed in Japanese Patent Application Publication No. 2011-72391 can be used. Figure 3 The device described in section 5.

[0196] Preferably, the interior of the die head 33 is heated to a predetermined molding temperature. The molding temperature is preferably set in the range of 150°C to 300°C. By heating and adjusting the temperature of the heating element within the device, the temperatures of the first polymer material 39 and the second polymer material 40 can be raised to high temperatures. Furthermore, the higher the rotational speeds of the screws 21a and 22a, the higher the temperatures of the first polymer material 39 and the second polymer material 40 can be, and their fluidity can be improved. At this time, by keeping the conveying speed of the connecting flexible tube substrate 31 constant and changing the ejection amounts of the molten first polymer material 39 and the second polymer material 40, the molding thicknesses of the inner layer 17 and the outer layer 18 can be adjusted.

[0197] The process of molding a polymer coating layer 15 onto a flexible tube substrate 31 using a continuous molding machine 20 will be described. During the molding process, the continuous molding machine 20 extrudes molten first polymer material 39 and second polymer material 40 from extrusion sections 21 and 22 towards the head 23. Simultaneously, the conveying section 25 operates, conveying the flexible tube substrate 31 towards the head 23. At this time, extrusion sections 21 and 22 are in a state of continuously extruding and supplying the first polymer material 39 and second polymer material 40 to the head 23. The first polymer material 39 and second polymer material 40 extruded from extrusion sections 21 and 22 towards gates 35 and 36 converge at the edges and are supplied to the molding channel 37 through the polymer channel 38 in an overlapping state. Thus, a double-layered polymer coating layer 15 is formed, consisting of an inner layer 17 using the first polymer material 39 and an outer layer 18 using the second polymer material 40 overlapping.

[0198] The connecting flexible tube substrate 31 is a substrate formed by connecting multiple flexible tube substrates 14 (each of which has a siloxane compound layer and a primer layer formed on its outer periphery). During transport within the forming channel 37, polymer coating layers 15 are continuously formed on the multiple flexible tube substrates 14. When forming the polymer coating layer 15 from one end 14a (top side) of a flexible tube substrate to the other end 14b (base side), the inner layer 17 is immediately thickened after the polymer is extruded using the extrusion sections 21 and 22. Then, the thickness ratio of the outer layer 18 is gradually increased in the middle portion towards the other end 14b. Therefore, it is preferable to control the amount of polymer extruded to form the aforementioned gradient thickness ratio of the polymer coating layer 15.

[0199] Since the connector 30 is the connecting part of the two flexible tube substrates 14, the control unit 26 is used to switch the ejection volume of the extrusion sections 21 and 22. Specifically, the control unit 26 preferably switches the ejection volume of the extrusion sections 21 and 22 so that the thickness ratio on the other end 14b side (base end side) of one flexible tube substrate 14 changes to the thickness ratio on the one end 14a side (top end side) of the next flexible tube substrate 14. When molding the polymer coating layer 15 from one end 14a side to the other end 14b side of the next flexible tube substrate 14, it is also preferable to control the extrusion sections 21 and 22 so that the thickness of the outer layer gradually increases from one end side to the other end side.

[0200] After the polymer coating layer 15 is formed to its final end and the connecting flexible tube substrate 31 is removed from the continuous forming machine 20, the connector component 30 is removed from the flexible tube substrate 14, separating them into individual flexible tube substrates 14. Then, a coating layer 16 is applied to the separated flexible tube substrates 14 on the polymer coating layer 15 to complete the flexible tube 3a. The completed flexible tube 3a is then conveyed to the assembly process of the electronic endoscope.

[0201] In this invention, when the polymer coating is multilayered, functional layers may be sandwiched between the layers constituting the multilayer.

[0202] The above description refers to the accompanying drawings and uses an electronic endoscope as an example to observe an image of the state of an object captured by a camera device. However, the present invention is not limited thereto and can also be applied to endoscopes that use optical image guides to observe the state of an object.

[0203] The flexible tube of this invention can be widely used in endoscopic medical devices. For example, it can also be used in instruments with clamps or wires at the tip of an endoscope, or in devices with baskets or brushes. Furthermore, endoscopic medical devices are defined not only as medical devices with an endoscope as their basic structure, but also broadly include medical or diagnostic devices with flexible insertion parts that are inserted into the body, such as remotely operated medical devices.

[0204] The endoscopic medical device of the present invention has an endoscope 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 endoscope flexible tube of the present invention into the insertion portion of the endoscopic medical device.

[0205] [Example]

[0206] The present invention will be further described in detail below through embodiments, but the present invention is not limited to these embodiments.

[0207] [Fabrication of Flexible Tubes for Endoscopes]

[0208] Production Figure 2The flexible tube shown has the following structure. Furthermore, the polymer coating, as shown in Table 2 below, can be either a single-layer or double-layer structure.

[0209] <Flexible tube substrate>

[0210] A flexible tube substrate is prepared as follows: a spiral tube 11 is formed using a stainless steel (SUS304) metal strip 11a, and this spiral tube 11 is covered with a tubular mesh 12 woven with SUS304 fibers. The flexible tube substrate has a length of 80 cm and a diameter of 12 mm. 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.

[0211] After degreasing the flexible tube substrate with acetone, it was immersed in a 1N sodium hydroxide aqueous solution at 50°C for 3 minutes. Then, it was rinsed three times with distilled water and dried in an oven heated to 100°C for 10 minutes to prepare the flexible tube substrate.

[0212] <Formation of the siloxane compound layer (L-1)>

[0213] Mix 20g of tetraethoxysilane, 20g of methyltriethoxysilane, 9g of ethanol, 14g of water, and 33g of 0.3% hydrochloric acid aqueous solution. Stir in a water bath at 63°C for 30 minutes, and then stir for another 30 minutes at room temperature to prepare mixture (A).

[0214] Mixture (A) is prepared by mixing 15g of a nonionic surfactant (polyethylene oxide-polypropylene oxide-polyethylene oxide triblock polymer, BASF's "PLURONIC P-123 (trade name)", number average molecular weight 5,800) and 12g of ethanol, and stirring at room temperature for 60 minutes.

[0215] The mixture (B) was diluted 25 times with 1-butanol and filtered through a filter with a sieve aperture of 0.45 μm to obtain a silica composition (C) (1.0% solids).

[0216] The cleaned flexible tube substrate was immersed in the silica composition (C) for 5 minutes, then lifted out and air-dried at 40°C for 30 minutes. The flexible tube substrate was then heated in an oven at 300°C for 5 minutes, thereby thermally decomposing and removing the nonionic surfactant, forming a siloxane compound layer (L-1) on the outer periphery of the flexible tube substrate. The siloxane compound layer (L-1) has a porous structure and an average layer thickness of 50 nm. This siloxane compound layer (L-1) contains hydroxyl groups.

[0217] <Formation of the siloxane compound layer (L-2)>

[0218] 20g of hydrolyzed silicate (N-103X, a trade name manufactured by COLCOAT Co., Ltd., Japan, with a solid content of 2.0% by mass and isopropyl alcohol / n-butanol solvent) was diluted with 980g of ethanol to prepare a silica composition (D) (solid content 0.04%). The cleaned flexible tubing substrate was immersed in the silica composition (D) for 1 minute, then removed and air-dried at 30°C for 30 minutes. The air-dried flexible tubing substrate was then heated in an oven at 100°C for 15 minutes, thereby forming a siloxane compound layer (L-2) on the outer periphery of the flexible tubing substrate.

[0219] <Formation of siloxane compound layers (L-3) to (L-10)>

[0220] In addition to using the components described in Table 1 below, the same procedure as for the siloxane compound layer (L-2) is followed to form siloxane compound layers (L-3) to (L-10) on the outer periphery of the flexible tube substrate. That is, each flexible tube substrate having siloxane compound layers (L-3) to (L-10) on its outer periphery is obtained. These siloxane compound layers (L-3) to (L-10) have hydroxyl groups.

[0221] <Formation of the epoxy resin layer (R-1)>

[0222] In a stainless steel container, 6.0 g of bisphenol A type epoxy resin (Mitsubishi Chemical Corporation "jER828" (trade name), epoxy equivalent 184-194 g / eq.) and 990 g of methyl ethyl ketone were mixed, and then 4.0 g of 1,6-diaminohexane was added. The mixture was stirred at room temperature for 15 minutes using a three-one motor to obtain an epoxy resin solution (E).

[0223] The cleaned flexible tube substrate was immersed in an epoxy resin solution (E) for 5 minutes, then lifted out and air-dried at 40°C for 30 minutes to allow the methyl ethyl ketone (MEK) to evaporate. The flexible tube substrate was then heated in an oven at 100°C for 3 hours to form an epoxy resin layer (R-1) on the outer periphery of the flexible tube substrate. The average thickness of the epoxy resin layer (R-1) was 80 nm.

[0224] [Table 1]

[0225]

[0226] <Notes to Table 1>

[0227] N-103X: Hydrolyzed silicate (N-103X (trade name) manufactured by COLCOAT Co., Ltd. of Japan, solid content 2.0% by mass, isopropyl alcohol / n-butanol solvent, in a hydrolyzed state, containing hydroxyl groups.)

[0228] HAS-10: Hydrolyzed silicate (manufactured by COLCOAT Co., Ltd. of Japan, "HAS-10" (trade name), solid content 10.2% by mass, methanol / isopropyl alcohol / ethanol solvent, in a hydrolyzed state, containing hydroxyl groups.)

[0229] The average layer thickness of the siloxane compound layer is calculated as follows.

[0230] The flexible tube substrate fabricated above was randomly cut at five points. The cross-sections of each siloxane compound layer were observed at 50,000x magnification using a scanning electron microscope (S-5500 (trade name), manufactured by Hitachi High Technology Co., Ltd.). The thickness of the siloxane compound layer formed on the outer periphery was obtained at each point on each cross-section. The average value of the five obtained thicknesses was taken as the average layer thickness.

[0231] <Formation of the primer layer>

[0232] Mix 150g of ethanol, 350g of water, and 1.0g of N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane (SI-1, trade name: KBM-603, manufactured by Shin-Etsu Chemical Co., Ltd.) to prepare a coating solution for primer layer formation.

[0233] The flexible tube substrate having a siloxane compound layer is immersed in the coating liquid for forming the primer layer prepared above at room temperature for 1 minute, air-dried for 10 minutes, and then placed in an oven at 100°C for 10 minutes to heat and dry, thereby preparing a flexible tube substrate with a primer layer on the siloxane compound layer (the flexible tube substrate used in Example 1).

[0234] Following the same procedure as described above, the flexible tube substrates used in each embodiment and comparative example were prepared using the raw materials listed in Table 2 (Tables 2-1 and 2-2). Furthermore, no primer layer was formed in Comparative Example 3 and Comparative Example 9.

[0235] <Formation of Polymer Coating>

[0236] A flexible endoscope tube with a polymer coating is fabricated by extruding a polymer as described in Table 2 below onto the outer periphery of a flexible tube substrate having a primer layer on a siloxane compound layer or an epoxy resin layer (molding temperature: polymer melting point + 10°C). The thickness of the polymer coating is 0.4 mm (in the case of a double-layer structure, the combined thickness of the two layers is 0.4 mm).

[0237] Furthermore, when the polymer coating is configured as a two-layer structure, both layers are simultaneously coated using bilayer extrusion molding. In this case, the ratio of the inner to outer layers at the top and rear ends is set to 80:20 (inner layer:outer layer) at the top and 20:80 (inner layer:outer layer) at the rear end. The thicknesses of the inner and outer layers form a gradient from the top to the rear end.

[0238] The following tests were conducted on the fabricated flexible tube. The results are summarized in Table 2 below.

[0239] [Experimental Example 1] Evaluation of the resilience of flexible tubes

[0240] Under conditions of 25°C and 50% relative humidity, the flexible endoscope tube fabricated above was fixed at positions 30cm and 50cm from one end. The tube at 40cm (the center of the flexible tube) was then pressed in 15mm along a direction perpendicular to the length of the flexible tube (diameter direction). The ratio of the repulsive force (b) after 30 seconds to the repulsive force (a) after 0.1 seconds was measured as the resilience (%). The repulsive force was measured using a force gauge (ZTS50N, trade name, manufactured by IMADA).

[0241] [Resilience (%)] = [(b) / (a)] × 100

[0242] Evaluate the above resilience against the following evaluation criteria. A score of "C" or above is considered acceptable.

[0243] <Resilience Evaluation Standard>

[0244] A: Resilience is above 80%.

[0245] B: Resilience is above 75% and below 80%.

[0246] C: Resilience is above 65% and below 75%.

[0247] D: Resilience is below 65%

[0248] [Experimental Example 2] Evaluation of the thermal durability of flexible tubes

[0249] The flexible tube of the endoscope prepared above was continuously heated at 60°C for 1,500 hours using a constant temperature and humidity chamber (KHWV-40HP manufactured by Satake Chemical & Machinery Co., Ltd.).

[0250] The following peeling test was performed on the flexible endoscope tube before and after heat treatment.

[0251] (Peeling test)

[0252] A 1 cm wide incision is made along the axial direction of the polymer coating of an endoscope flexible tube, reaching the flexible tube substrate. The resulting 1 cm wide incision is located on the outer circumferential surface of the polymer coating. Holding the end of the 1 cm wide incision, peeling is performed along the axial direction of the flexible tube at a constant speed, while maintaining a 90° angle between the flexible tube substrate and the peeled polymer coating. The 90° peel strength between the flexible tube substrate and the polymer coating (the innermost layer in the case of two layers) is then measured. The peel strength is measured using a force gauge and is expressed in N / cm.

[0253] The 90° peel strength of the flexible endoscope tube before heat treatment is set as "PSB(1)", and the 90° peel strength of the flexible endoscope tube after heat treatment is set as "PSA(1)". Calculate the ratio of "PSA(1)" to "PSB(1)" {(PSA(1) / PSB(1))×100(%)}, and evaluate it against the following standards. "C" or above is considered qualified.

[0254] <Evaluation Standard for Thermal Durability>

[0255] AA: above 90%

[0256] A: Above 80% but below 90%

[0257] B: 60% or more but less than 80%

[0258] C: Above 40% but below 60%

[0259] D: Below 40%

[0260] [Experimental Example 3] Evaluation of Hydrogen Peroxide Tolerance

[0261] The ends of the above-prepared flexible endoscope tube were capped with Teflon (registered trademark) plugs and immersed in 5.0% hydrogen peroxide water at 55°C for 150 hours. After immersion, the surface was thoroughly washed with water to prepare the hydrogen peroxide-immersed flexible endoscope tube.

[0262] Peel tests were conducted on the flexible endoscope tubes before and after immersion in hydrogen peroxide water, in the same manner as in Example 2, and the peel strength was measured. The 90° peel strength of the flexible endoscope tube before immersion in hydrogen peroxide water was set as "PSB(2)", and the 90° peel strength of the flexible endoscope tube after immersion in hydrogen peroxide water was set as "PSA(2)". The ratio of "PSA(2)" to "PSB(2)" was calculated as {(PSA(2) / PSB(2))×100(%)}, and evaluated against the following standard. "C" or above is considered qualified.

[0263] <Hydrogen Peroxide Tolerance Evaluation Standard>

[0264] AA: above 90%

[0265] A: Above 80% but below 90%

[0266] B: Over 60% of the month; below 80%.

[0267] C: Above 40% but below 60%

[0268] D: Below 40%

[0269] [Table 2-1]

[0270]

[0271]

[0272] [Table 2-2]

[0273]

[0274]

[0275] <Notes to Table 2>

[0276] Example: Implementation

[0277] Comparison: Example

[0278] In Comparative Example 2, for ease of comparison with the Examples, an epoxy resin layer (R-1) is described in the row of siloxane compound layers.

[0279] The abbreviations recorded in the table above are as follows.

[0280] (Silane coupling agent)

[0281] (SI-1):

[0282] N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane (trade name: KBM-603, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0283] (SI-2):

[0284] 3-Aminopropyltrimethoxysilane (trade name: KBM-903, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0285] (SI-3):

[0286] N-Methylaminopropyltrimethoxysilane

[0287] (SI-4):

[0288] 3-Uretopropyltrialkoxysilane (trade name: KBE-585, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0289] (SI-5):

[0290] N-Phenylacetyl-3-aminopropyltrimethoxysilane (trade name: KBM-573, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0291] (SI-6):

[0292] 3-Trimethoxysilylpropylsuccinic anhydride (trade name: X-12-967C, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0293] (SI-7):

[0294] (3-Methacryloxypropyl)trimethoxysilane (trade name: KBM-503, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0295] (SI-8):

[0296] 3-Epoxypropoxypropyltrimethoxysilane (trade name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0297] (SI-9):

[0298] 3-Mercaptopropyltrimethoxysilane (trade name: KBM-803, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0299] (Aluminum coupling agent)

[0300] (AL-1):

[0301] Aluminum sec-butoxide (trade name: ASBD, manufactured by Sichuan Research Institute of Fine Chemicals Co., Ltd.)

[0302] (AL-2):

[0303] Aluminum triacetylacetonate (trade name: ORGATICS AL-3100, manufactured by Matsumoto Fine Chemicals Co., Ltd.)

[0304] (AL-3):

[0305] Ethyl diacetate, aluminum monoacetylacetonate (trade name: ORGATICS AL-3200, manufactured by Matsumoto Fine Chemicals Co., Ltd.)

[0306] (AL-4):

[0307] Ethyl triacetate aluminum (trade name: ORGATICS AL-3215, manufactured by Matsumoto Fine Chemicals Co., Ltd.)

[0308] (AL-5):

[0309] Aluminum diisopropoxide octadecyl acetoacetate (trade name: PLENACT AL-M, manufactured by Ajinomoto Fine-Techno Co., Inc.)

[0310] (Zirconium coupling agent)

[0311] (ZR-1):

[0312] Tetra-n-propanezirconium (trade name: ORGATICS ZA-45, manufactured by Matsumoto Fine Chemicals Co., Ltd.)

[0313] (ZR-2):

[0314] Zirconium tetrabutoxide (trade name: ORGATICS ZA-65, manufactured by Matsumoto Fine Chemicals Co., Ltd.)

[0315] (ZR-3):

[0316] Zirconium tetraacetylacetonate (trade name: ORGATICS ZC-150, manufactured by Matsumoto Fine Chemicals Co., Ltd.)

[0317] (ZR-4):

[0318] Zirconium lactate (trade name: ORGATICS ZC-300, manufactured by Matsumoto Fine Chemicals Co., Ltd.)

[0319] (ZR-5):

[0320] Tri-n-Butyl Zirconium Stearate (trade name: ORGATICS ZC-320, manufactured by Matsumoto Fine Chemicals Co., Ltd.)

[0321] (Titanium coupling agent)

[0322] (TI-1):

[0323] Tetrabutyl titanate (trade name: ORGATICS TA-21, manufactured by Matsumoto Fine Chemicals Co., Ltd.)

[0324] (TI-2):

[0325] Tetrabutyl titanate dimer (trade name: ORGATICS TA-23, manufactured by Matsumoto Fine Chemicals Co., Ltd.)

[0326] (TI-3):

[0327] Isopropyl triisostearate titanate (trade name: PLENACT TTS, manufactured by Ajinomoto Fine-Techno Co., Inc.)

[0328] (TI-4):

[0329] Dioctyl bis(di-tetranyl)phosphotitanium ester (trade name: PLENACT46B, manufactured by Ajinomoto Fine-Techno Co., Inc.)

[0330] (TI-5):

[0331] Diisopropyl bis(dioctyl pyrophosphate) titanate (trade name: PLENACT38S, manufactured by Ajinomoto Fine-Techno Co., Inc.)

[0332] (U-1):

[0333] Polyether polyurethane elastomer (trade name: PANDEX T-8185, manufactured by DIC)

[0334] (U-2):

[0335] Polyether polyurethane elastomer (trade name: Miractran E380, manufactured by Nippon Polyurethane Co., Ltd.)

[0336] (U-3):

[0337] Polyester polyurethane elastomer (trade name: Miractran E480, manufactured by Nippon Polyurethane Co., Ltd.)

[0338] (U-4):

[0339] Polycarbonate polyurethane elastomer (trade name: SPANDEX T-9280, manufactured by DIC)

[0340] (E-1):

[0341] Polyester elastomer (trade name: PELPRENE P-40B, manufactured by Toyobo Co., Ltd.)

[0342] (Ae-1):

[0343] Polyamide elastomer (trade name: PEBAX4533, manufactured by Arkema)

[0344] (P-1):

[0345] Polyolefin elastomer: ZELAS MC707 (trade name), manufactured by Mitsubishi Chemical Corporation.

[0346] (F-1):

[0347] Fluorinated elastomer: DAI-EL T-530 (trade name), manufactured by Daikin Industries, Ltd.

[0348] The following conclusions can be drawn from Table 2.

[0349] The flexible tubes of Comparative Examples 1 and 6-8, which do not have the siloxane compound layer specified in this invention, have poor heat durability and hydrogen peroxide water resistance even when they have a primer layer.

[0350] Comparative Example 2's flexible tube has an epoxy resin layer instead of a siloxane compound layer between the flexible tube substrate and the primer layer. However, this flexible tube has poor heat durability and hydrogen peroxide water resistance.

[0351] Comparative Examples 3 and 9 have a siloxane compound layer as specified in this invention, but lack a primer layer as specified in this invention. These flexible tubes exhibit poor resilience, heat resistance, and hydrogen peroxide water resistance.

[0352] The flexible tube of Comparative Example 4 has a fluorinated elastomer layer as a polymer coating layer. Furthermore, the flexible tube of Comparative Example 5 has a fluorinated elastomer layer as a polymer coating layer on the side in contact with the primer layer. That is, these flexible tubes do not have the polymer coating layer specified in this invention on the side in contact with the primer layer. The flexible tube of Comparative Example 4 has poor resilience, heat durability, and hydrogen peroxide water resistance, while the flexible tube of Comparative Example 5 has poor heat durability and hydrogen peroxide water resistance.

[0353] In contrast, the flexible tubes of the present invention in Examples 1 to 48 have sufficient resilience, excellent thermal durability, and excellent resistance to hydrogen peroxide water.

[0354] Symbol Explanation

[0355] 2. Electronic endoscope (Endoscope)

[0356] 3. Insertion section

[0357] 3a Flexible tube

[0358] 3b Corner

[0359] 3C top part

[0360] 5 Main Operating Unit

[0361] 6. Universal Rope

[0362] 11. Spiral tube

[0363] 11a Metal strip

[0364] 12 cylindrical mesh

[0365] 13 Pipe head

[0366] 14 Flexible tube substrate

[0367] 14a Top side

[0368] 14b Basement side

[0369] 15 Polymer Coating

[0370] 16. Top Coating

[0371] 17 Inner Layer

[0372] 18 Outer layer

[0373] X-shaped bend, side 3b (soft)

[0374] Y Main operating section 5 sides (hard)

[0375] 20 Continuous forming machine (manufacturing equipment)

[0376] Extrusion sections 21 and 22

[0377] 21a Screw

[0378] 22a screw

[0379] 23 Head

[0380] 24 Cooling section

[0381] 25. Conveying Department

[0382] 26 Control Department

[0383] 28 Supply cylinders

[0384] 29. Winding drum

[0385] 30 Connector components

[0386] 31 Connecting Flexible Tube Substrate

[0387] 32 pipe fitting

[0388] 33 mold heads

[0389] 34 Support body

[0390] Gates 35 and 36

[0391] 37 Forming Channel

[0392] 38 Polymer Channels

[0393] 39 First Polymer Material (Soft Polymer)

[0394] 40 Second polymer material (rigid polymer)

Claims

1. A flexible tube for endoscopes, comprising a flexible tube substrate made of metal, a siloxane compound layer on the flexible tube substrate, a primer layer on the siloxane compound layer, and a polymer coating layer on the primer layer. The siloxane compound has hydroxyl groups. The polymer coating layer contains at least one compound selected from polyamide, polyester, polyurethane, and polyolefin on the side in contact with the primer layer.

2. The flexible endoscope tube according to claim 1, wherein, The siloxane compound includes organosiloxane compounds.

3. The flexible endoscope tube according to claim 1 or 2, wherein, The primer layer contains at least one of silane coupling agent, titanium coupling agent, zirconium coupling agent and aluminum coupling agent.

4. The flexible endoscope tube according to claim 1 or 2, wherein, The primer layer contains a silane coupling agent.

5. The flexible endoscope tube according to claim 1 or 2, wherein, The primer layer contains an aminosilane coupling agent.

6. The flexible endoscope tube according to claim 1 or 2, wherein, The metal constituting the flexible tube substrate is stainless steel.

7. The flexible endoscope tube according to claim 1 or 2, wherein, The metal constituting the flexible tube substrate has a passivation film on its surface.

8. The flexible endoscope tube according to claim 1 or 2, wherein, The polymer coating layer is a single-layer or multi-layer structure, and the layer in contact with the primer layer contains at least one compound selected from polyamide, polyester, polyurethane and polyolefin.

9. The flexible endoscope tube according to claim 1 or 2, wherein, The polymer coating has a double-layer structure, and the ratio of the thickness of the inner and outer layers of the double-layer structure varies gradually along the axial direction of the flexible tube substrate.

10. The flexible endoscope tube according to claim 9, wherein, The thickness ratio of the inner layer to the outer layer is 95:5 to 60:40 at one end of the flexible tube for the endoscope, and 5:95 to 40:60 at the other end.

11. An endoscopic medical device comprising an endoscope flexible tube according to any one of claims 1 to 10.

12. A method for manufacturing a flexible tube for an endoscope, comprising: depositing a siloxane compound layer on a flexible tube substrate made of metal; depositing a primer layer on the siloxane compound layer; and depositing a polymer coating layer on the primer layer. The siloxane compound has hydroxyl groups. The polymer coating layer contains at least one compound selected from polyamide, polyester, polyurethane, and polyolefin on the side in contact with the primer layer.

13. A method for manufacturing an endoscopic medical device, comprising assembling an endoscopic flexible tube obtained by the method for manufacturing an endoscopic flexible tube as described in claim 12 into the insertion portion of the endoscopic medical device.

14. A method for manufacturing an endoscopic medical device, comprising assembling an endoscope flexible tube according to any one of claims 1 to 10 into the insertion portion of the endoscopic medical device.

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