| 摘要 |
PROBLEM TO BE SOLVED: To protect wiring by covering wiring across on a slit opening part with a protection paint film where an initial elastic rate is set to a specific range, the breaking point strength of the specific range is provided, an expansion rate is set to a specific range, electric insulation property is sufficient, a thermal decomposition start temperature is set to the specific range, and a solder heat resistance property exceeding a specified one is shown. SOLUTION: The one-side surface of a number of wires 5 across a slit-shaped opening part 4 of a bending part 3 of a flexible wiring board 2 is covered with a protection paint film 6. The paint film 6 is formed by a covering composition where an initial elastic rate is set to 1-70 kg/mm<2> as a film, breaking point strength is set to approximately 0.5-20 kg/mm<2> at 25 deg.C, an expansion rate is set to approximately 30-500%, electric insulation property is maintained at a sufficient level, thermal decomposition start temperature is set to approximately 250-500 deg.C, and a solder heat resistance property of 30 seconds or more at 200 deg.C is shown. This sort of protection paint film 6 is provided, thus preventing a number of the wires 5 consisting of metal foil from being broken at the bending part 3 even when the flexible wiring board 2 is bent by, for example, 180 deg.C at the slit opening part 4 of a support film 1. |
