| 摘要 |
PROBLEM TO BE SOLVED: To stabilize a transmission loss and dimensions and improve heat resistance by surrounding fibers with specific resin. SOLUTION: Seven or more fibers are formed of P-polymethyl metacrylate core resin. Sheath resin for surrounding the fibers is formed of resin containing a vinylidene fluoride component at 30-92 mol.%, a tetrafluoroethylene component at 1-55 mol.% and a hexafluoropropylene component at 8-25 mol.%, with a refractive index measured at 20 deg.C by a sodium D-line being 1.350-1.380, the Shore D hardness value at 23 deg.C being 30-55, and a melt flow index (under the conditions of 230 deg.C, 3.8 kg in load, 2 mm in orifice diameter and 8 mm in orifice length) showing a fluidity of 5 g/10 min.-100 g/10 min. The core fibers are surrounded with this sheath resin and compositely spinned. This sheath resin is a ternary copolymer composed of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene, or a binary copolymer composed of vinylidene fluoride and hexafluoropropylene. |
