| 摘要 |
PURPOSE:To make it possible to bend a cable having <=300mm radius and to guarantee sufficient reliability even if a non-metallic optical cable is dipped into water by using a specific FRP excellent in the breaking life of bending stress. CONSTITUTION:In the non-metallic optical cable using glass fiber plastic (FRP) obtained by reinforcing thermosetting plastic by glass fiber as a tensile strength substance, the FRP satisfies the conditions of the shown inequality. The deterioration of the intensity of glass fibers will be generated when component substances of the glass fiber are soluble in water and cracks grow. Thereby, it is preferable to use water-insoluble glass fiber, e.g. a glass fiber reducing the contents of element such as Ca, B and Na which are easily soluble in water. Thus, the FRP for non-metallic optical cable tensile strength substance capable of being laid on a position to be easily dipped into water in a manhole or the like can be obtained.
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