| 摘要 |
PROBLEM TO BE SOLVED: To provide a moisture-resistant coverlay film wherein its steam-transmittance is so small as to obtain a high-level moisture resistance stably over a long term, and when covering with it a flexible printed wiring board, the negative-terminal side thereof is suppressed from becoming basic by a moisture and the wiring peeling thereof is suppressed from generating, and to provide the flexible printed wiring board using the coverlay film. SOLUTION: The moisture-resistant coverlay film has a base-material film comprising a polyimide film and has an organic moisture-resistant film laminated on the surface of the base-material film. The organic moisture-resistant film contains at least the polyvalent metal salt of a polycarboxylic-acid-based polymer (A). Also, in the infrared-ray absorption spectrum of the moisture-resistant coverlet film, its area ratioα[peak(3,700-2,500 cm<SP>-1</SP>)/peak(1,800-1,500cm<SP>-1</SP>)] is made not larger than 2.5, and its peak ratioβ[peak(1,560 cm<SP>-1</SP>)/peak(1,700 cm<SP>-1</SP>)] is made not smaller than 1.2. COPYRIGHT: (C)2006,JPO&NCIPI
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