| 摘要 |
PURPOSE:To improve characteristics of strength and bending by drawing and covering a bundle of optical fiber cores in a peripheral and a lengthwise direction with a liquid crystal high polymer which is fused and extruded across a buffer layer of thermoplastic rubber or material which is foamed when heated. CONSTITUTION:Optical fiber cores 2 are bundled around a center tensile strength body 1, the thermoplastic rubber 3''' is extruded from an internal layer die 6 while run in a nipple 5, and the liquid crystal high polymer 4' is extruded from an external layer die 7. At this time, the extrusion temperature of the liquid crystal high polymer 4' is set a little bit higher and the extrusion pressure of the thermoplastic rubber 3''' is set higher. Consequently, the liquid crystal high polymer 4' while extruded from the external diameter die 7 and held at high temperature above fusion temperature deforms radially with pressure applied to the thermoplastic rubber 3''' and is drawn lengthwise, so that molecules are oriented in the peripheral and lengthwise directions. Thus, the characteristics of both strength and bending are improved.
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