| 摘要 |
PROBLEM TO BE SOLVED: To retain stable electric properties and mechanical strength even in very high temperature by using an alumina yarn or a silica yarn as a pressure winding material for a mica tape attached longitudinally as a flame resistant layer. SOLUTION: Of a mica tape produced by sticking a polyethylene film and mica dusts on a soft copper single wire conductor 1, the mica side is longitudinally attached to the conductor 1 side and a fired alumina yarn is transversely wound to pressure the mica tape. Moreover, the outside is pushed down by an alumina yarn in the same way and further a mica tape pressured and wound by an alumina yarn is formed outside to form a flame resistant layer 2 of a longitudinally attached mica tape. An insulation layer 3 is formed on the outside of the flame resistant layer 2 to give an insulated core wire 7 and insulated core wires 7 produced by such a method are stranded while using a polypropylene string as an intermediate material, the resultant stranded wires are pressure wound with a polyester tape and successively coated with an ethylene type resin composition by extrusion to form a sheath 6 and a flame resistant electric wire is thus manufactured. |
