| abstract |
(57) [Summary] [PROBLEMS] For solder resist of flexible printed wiring board, excellent in flexibility of cured product, excellent in solder heat resistance, heat deterioration resistance, electroless gold plating resistance, can be developed with organic solvent or dilute alkali solution. And a resin composition suitable for a layer-sensitive insulating layer. A resin composition containing a specific urethane oligomer (A), at least one compound containing a dihydrobenzoxazine ring (B) in a molecule, a diluent (C), and a photopolymerization initiator (D). |