| 摘要 |
PURPOSE:To obtain the titled coated optical fiber having adhesiveness to the optical fiber, easy releasability from the secondary coated layer, a high-precision outer diameter, and highly durable characteristics by coating a coating material at least twice, baking the coating, and pluralizing the primary coated layer. CONSTITUTION:A soln. of a thermosetting resin having high adhesiveness to an optical fiber is coated on the outer circumference of an optical fiber 2 which is obtained by passing a quartz preform rod 1 through a spinning furnace A, and spinning the rod into threads by using a spary type coating device B, and the coated fiber is baked in a baking furnace C at about 500 deg.C to form an inner layer part 31 for the primary coated layer 3. Then a resin which is releasable from the secondary coated layer 4 is coated on the part 31 by passing the fiber through a pressure-die type deivce D, and baked in a baking furnace E to form the outer layer part 32 of the primary coated layer 3. The primary coated layer 3 having <=3mum thickness and >=D70 Shore hardness at ordinary temp. is formed in this way. Then the secondary coated layer 4 having greater thickness than the coated layer 3 is formed on the outer surface of the coated layer 3 by passing said coated fiber through a die type coating device F and a baking device G. A coated layer 5 is further formed with an extrusion coating device H, and the fiber is wound up after cooling by a winder J.
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