| 摘要 |
PURPOSE:To improve the optical transmission power as well as the mechanical performance and heat resistance of a polymer as the sheath material by specifying the ratio between the coefft. of linear thermal expansion of a polymer forming the core material part which is in contact with the sheath material layer and the coefft. of linear thermal expansion of a polymer forming the coating layer which is in contact with the sheath material layer. CONSTITUTION:The ratio alpha3/alpha1 between the coefft. alpha1 of linear thermal expansion of a polymer forming a core material part 1 which is in contact with a sheath material layer 2 and the coefft. alpha3 of linear thermal expansion of a polymer forming a coating layer 3 which is in contact with the layer 2 is adjusted to 0.6-1.7. The coefft. of linear thermal expansion of the polymer forming the layer 3 can be adjusted by mixing the polymer with an inorg. or org. filler such as carbon black, talc or glass fiber. It is industrially advantageous that the coating layer 3 and the core material part 1 are made of the same polymer. |
