| abstract |
(57) [Summary] An object of the present invention is to provide a flexible printed wiring board material that is used for a flexible printed wiring board, a coverlay material, and a bonding sheet. Provided are an epoxy resin composition having heat resistance and moisture resistance, and a substrate for flexible printed wiring, a coverlay material, and a bonding sheet using the same. The composition contains an epoxy resin (a), a curing agent (b), and a phenolic hydroxyl group-containing polyamide-polybutadiene-acrylonitrile copolymer (c), and has a compounding weight ratio of (c) / ｛(a) + ( b) + (c)｝ = 0.05- An epoxy resin composition having a ratio of 0.90. |