| 摘要 |
PURPOSE:To improve the heat resistance and mechanical properties of the titled fiber and to decrease the light transmission loss at a high temp. by using polycarbonate for a core and specific fluorine-contained polycarbonate for a sheath. CONSTITUTION:The core of the above-mentioned fiber is formed of the polycarbonate and the sheath is formed of the fluorine-contained polycarbonate (A) which has a refractive index as low as >=0.07, has >=8.0 solubility parameter and is substantially transparent. The essential component of the polymer A is preferably the unit expressed by the formula (where Rf, Rf' denote fluoroalkyl of 1-6C or perfluoroalkyl of 1-4C). For example, the polymer A is formed by the reaction of bis(4-hydroxyphenyl)hexafluoropropane and phosgene and the fiber is formed by passing the polymer through a mouthpiece for compounding and extruding the same into the double structure of the core and sheath. |
