| 摘要 |
PROBLEM TO BE SOLVED: To obtain an optical fiber showing good pneumatic conveying characteristics and high productivity by applying a foamable UVcuring resin liquid with addition of a thermally expanding foaming material, heating the liquid to foam and irradiating the layer with UV rays to form a foamed layer. SOLUTION: A raw wire of an optical fiber released from a release drum 32 is introduced along a pulley to coating dies 24. In the coating dies 24, the optical fiber wire 22 is coated with a UVcuring resin liquid containing a thermally expanding foaming material and then immediately introduced into a heating furnace where the thermally expanding foaming material is decomposed and foamed by heating. By changing the furnace temp. and travelling speed, the magnification of foaming can be controlled. The optical fiber wire 22 heated in the heating furnace 26 is immediately sent to a UV irradiating device 27 where the fiber is irradiated with UV rays to harden the UV-curing resin liquid as foamed to form a foamed layer. Thus, an optical fiber wire 28 for pneumatic conveying can be obtd. The obtd. fiber is wound along a pulley on a winding drum 30. |
