| 摘要 |
PROBLEM TO BE SOLVED: To obtain a plastic optical fiber which is usable for a long time in the high-temp. environment and is free from noises from outside by providing the outer side of a sheath layer with a light shielding layer consisting of a specific resin compsn. SOLUTION: A core 1 consists of a polymethyl methacrylate(PMMA) resin. The sheath layer 2 is formed of a transparent fluororesin having the refractive index lower than the refractive index of the PMMA resin used for the core 1. The light shielding layer 3 is formed by tightly coating the sheath layer 2 with a coating resin compsn. prepd. by adding carbon black to a vinylidene fluoride based resin having >=50 wt.% vinylidene fluoride structural unit in such a manner that the thickness attains 3 to 300μm. While the carbon black may be incorporated into the coating resin compsn. up to about 10 wt.% the content thereof is preferably <=7 wt.% in order to smoothly execute the coating to the sheath layer 2. Further, the sheath layer is provided with an external coating layer 5 consisting of a thermoplastic resin in order to impart mechanical strength, chemical resistance, fashion characteristic, identifiability, etc., to the fiber. |
