Flexible tube for endoscopes and method for producing same

Abstract

The present invention provides a flexible tube having a cylindrical flexible tube base that has flexibility and a resin layer that coats the flexible tube base, in which the resin layer is configured by at least two layers of a first layer that contains a specific resin and a second layer that contains a specific resin, or in which the resin layer is a single layer or multiple layers of two or more layers, and a layer A that is any of the resin layers includes polyester elastomers, and, hindered phenol compounds or hindered amine compounds.

What is claimed is: 
     
         1 . A flexible tube having a cylindrical flexible tube base that has flexibility and a resin layer that coats the flexible tube base,
 wherein the resin layer is configured by at least two layers of a first layer and a second layer,   the first layer includes one or more elastomers or chain-extended forms thereof selected from a group consisting of polyester elastomers, polyurethane elastomers, and polyamide elastomers, and   the second layer includes chain-extended forms of two or more elastomers selected from a group consisting of polyester elastomers, polyurethane elastomers, and polyamide elastomers.   
     
     
         2 . The flexible tube according to  claim 1 ,
 wherein a chain extender for preparing the chain-extended forms of the elastomers is selected from polyfunctional epoxy compounds, polyfunctional isocyanate compounds, polyfunctional amino compounds, oxazoline compounds, carbodiimide compounds, and acid anhydrides.   
     
     
         3 . The flexible tube according to  claim 2 ,
 wherein the chain-extended form of the elastomer is obtained by adding at least one catalyst selected from amine compounds and tin chelate to the elastomer in addition to the chain extender.   
     
     
         4 . The flexible tube according to  claim 2 ,
 wherein the chain-extended form of the elastomer is obtained by adding 0.01 to 10 parts by mass of the chain extender with respect to 100 parts by mass of the elastomer.   
     
     
         5 . The flexible tube according to  claim 3 ,
 wherein the chain-extended form of the elastomer is obtained by adding 0.01 to 3 parts by mass of the catalyst with respect to 100 parts by mass of the elastomer.   
     
     
         6 . The flexible tube according to  claim 1 ,
 wherein two or more of the elastomers which configure the second layer are a combination of polyester elastomers and at least one selected from polyurethane elastomers and polyamide elastomers.   
     
     
         7 . The flexible tube according to  claim 1 ,
 wherein the resin layer is soluble in 1,1,1,3,3,3-hexafluoro-2-propanol and substantially not cross-linked.   
     
     
         8 . The flexible tube according to  claim 1 ,
 wherein the first layer of the resin layer is an inner layer which coats an entire peripheral surface around an axis of the flexible tube base, and the second layer is an outer layer which contacts the first layer and coats an entire peripheral surface around an axis of the first layer, and   the resin layer is formed of two layers of the inner layer and the outer layer.   
     
     
         9 . A flexible tube having a cylindrical flexible tube base that has flexibility and a resin layer that coats the flexible tube base,
 wherein the resin layer is a single layer or multiple layers of two or more layers, and a layer A which is any out of the resin layers includes polyester elastomers, and, hindered phenol compounds or hindered amine compounds.   
     
     
         10 . The flexible tube according to  claim 9 ,
 wherein the content of the polyester elastomers in a resin component is 50 mass % or more in the layer A.   
     
     
         11 . The flexible tube according to  claim 9 ,
 wherein the layer A further contains polyurethane elastomers or polyamide elastomers.   
     
     
         12 . The flexible tube according to  claim 9 ,
 wherein the layer A contains both hindered phenol compounds and hindered amine compounds.   
     
     
         13 . The flexible tube according to  claim 9 ,
 wherein the content of the hindered phenol compounds is 0.01 to 5 parts by mass with respect to 100 parts by mass of a resin component in the resin layer, and   the content of the hindered amine compounds is 0.01 to 5 parts by mass with respect to 100 parts by mass of a resin component in the resin layer.   
     
     
         14 . The flexible tube according to  claim 9 ,
 wherein the hindered phenol compounds have structure sites represented by the following Formula (1) and the hindered amine compounds have structure sites represented by the following Formula (2),   
       
         
           
           
               
               
           
         
         where, R 1  and R 2  each independently indicate a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or an aralkyl group having 7 to 36 carbon atoms, R 3  to R 6  each independently indicate a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, R 7  indicates a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, or —OR 8 , R 8  indicates a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and * indicates a bonding position. 
       
     
     
         15 . The flexible tube according to  claim 14 ,
 wherein the hindered phenol compounds are represented by the following Formula (1-1) or (1-2),   
       
         
           
           
               
               
           
         
         where, R 1  and R 2  are the same as in Formula (1), L indicates a single bond or a divalent linking group, p indicates an integer of 2 to 4, A 1  indicates a divalent to tetravalent linking group, R 9  to R 12  are the same as R 1 , and R 13  represents a reactive organic substituent group. 
       
     
     
         16 . The flexible tube according to  claim 14 ,
 wherein the hindered amine compounds are compounds represented by the following Formula (2-1) or compounds which have repeating units represented by (2-2),   
       
         
           
           
               
               
           
         
         where, R 3  to R 7  are the same as in Formula (2), q indicates an integer of 2 or greater, D 1  indicates a divalent or higher linking group, r represents an integer, Q represents an (s+2)-valent linking group, and s represents 1 or 2. 
       
     
     
         17 . The flexible tube according to  claim 9 ,
 wherein the resin layer is multiple layers and the layer A configures an outermost layer of the resin layer.   
     
     
         18 . The flexible tube according to  claim 17 ,
 wherein a layer B other than the outermost layer contains at least one resin selected from polyester elastomers, polyurethane elastomers, and polyamide elastomers.   
     
     
         19 . The flexible tube according to  claim 18 ,
 wherein the content of polyurethane elastomers in a resin component of the layer B is 50 mass % or more.   
     
     
         20 . The flexible tube according to  claim 9 ,
 wherein a ratio of thicknesses of the inner layer and the outer layer incrementally changes in an axial direction of the flexible tube base with respect to a thickness of the entire resin layer, and   a ratio of the thicknesses of the inner layer and the outer layer at one end of the flexible tube base is Inner layer:Outer layer=5:95 to 40:60, a ratio of the thicknesses at another end of the flexible tube base is Inner layer:Outer layer=95:5 to 60:40, and the ratio of the thicknesses is reversed between both ends.