| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent the generation of short-circuit of a heating wire due to a bend thereof by the resin pressure at the time of injection molding by performing the injection molding in the condition that fused variable of the resin of a coating resin layer of a resin coated heating wire is restricted to a specified value or less. SOLUTION: A resin coated heating wire 2 is spirally wound around a core 12, which is formed of a pair of cylindrical pieces 121, 122, without generating a clearance between them. Thereafter, the core 12 wound with the resin coated heating wire 2 is inserted into an outer mold so as to seal the mold, and the fusion resin of the joint forming resin 3, which is supplied from an injection molding machine, is injected for molding from a resin gate into the mold, and the pressure is maintained for the predetermined time. At this stage, injection molding is performed in the condition that the resin fused variable of the resin coating layer of the resin coated heating wire 2 is restricted to 50 wt.% or less. Thereafter, the mold is opened, and tips of the cylindrical pieces 121, 122 are opened so as to remove the core 12, and an electric fusion joint, which is embedded in the wall without generating short-circuit of the heating wire, is obtained.</p> |
