| 摘要 |
PURPOSE:To improve the heat-resisting property of the titled fiber, and to lessen the increase of the optical transmission loss, even in case of using in the surrounding of a high temp. by constituting the titled fiber of a core layer and a sheath layer as a fundamental constituting unit, and by composing the core layer of a polymer represented by a specified formula. CONSTITUTION:The titled fiber comprises the core layer and the sheath layer as the fundamental constituting unit, and the core layer is composed of a poly carbonate polymer having a repeating unit shown by formula I wherein R1-R4 are each hydrogen atom. or methyl group and may be the same or different with each other, A is a group shown by formula II (wherein, when A is isopropylidene group, R is not hydrogen atom). And, the refractive index of the core layer is larger than that of the sheath layer by >=0.01. Thus, the heat- resisting property of the titled fiber is improved, and the increase of the optical transmission loss is lessened, even in case of using said fiber in the surrounding of the high temperature. |
