| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for producing an endoscope flexible tube excellent in operability, heat resistance and chemical resistance. <P>SOLUTION: The method comprises the steps of: preparing a flexible tube assembly 64 including a spiral tube formed by spirally winding a metal strip and a cylindrical mesh body formed by knitting metal wires covering the spiral tube; and covering the flexible tube assembly 64 with an outer coat 68 from one end toward the other end of the flexible tube assembly by using an extrusion molding machine 138 wherein the outer coat has a lower layer formed of a thermoplastic polyurethane elastomer and an upper layer formed of a thermoplastic polyester elastomer and the total thickness of the layers is made constant. The outer coat 68 covers the flexible tube assembly 64, wherein the melt viscosity ratio (thermoplastic polyurethane elastomer/thermoplastic polyester elastomer: with reference to the exit temperature of the extrusion molding machine) between the thermoplastic polyurethane elastomer and the thermoplastic polyester elastomer is set to fall within a range from 1 to 35, and the thickness of the upper layer and the lower layer is gradually varied from one end to the other end. <P>COPYRIGHT: (C)2011,JPO&INPIT |
