| 摘要 |
PURPOSE:To provide superior heat resistance and mechanical properties to the titled fiber and to allow the fiber to show satisfactory optical transmission characteristics even at high temp. by using a core material layer of transparent polycarbonate having 0.4-0.6dl/g intrinsic viscosity and a sheath material layer as basic constituent units. CONSTITUTION:A core material layer 11 and a sheath material layer 12, or a core material layer 21, a sheath material layer 22 and a protective layer 23 are used as basic constituent units. The core material layers 11, 21 are made of polycarbonate, preferably alicyclic or aromatic polycarbonate represented by formula I (where R is a group represented by formula II). The polycarbonate is transparent and has 0.40-0.60dl/g, preferably 0.45-0.55dl/g intrinsic viscosity [eta] in methylene chloride at 20 deg.C. |
