| 摘要 |
PROBLEM TO BE SOLVED: To enable a flexible printed-wiring board to be manufactured by a circuit step in high working efficiency by a method wherein the whole transmission degree and the mirror gloss degree of the visible region ray from an electric insulating film side are set up within a specific range. SOLUTION: The blending amount of a black pigment into a thermosetting adhesive or an electric insulating film in the state of a cover lay film is specified as follows i.e., the contentαof the black pigment per unit area to a transmission surface to be 100<=α<=1000μg/cm<2> , finally, the whole transmission degree X in the vissible region ray from the electric insulating film side to be 0<=X<=3%, while the mirror glass degree Y to be 0<Y<=50%. Through these procedures, the shielding cover lay film having excellent shielding property can be manufactured making needless of the black ink printing step on a flexible printed-wiring board in a circuit step thereby enabling the workability, working efficiency to be improved.
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