SOLDER RESIST, DRY FILM THEREOF, CURED PRODUCT AND PRINTED WIRING BOARD

摘要

Disclosed is a solder resist which enables to have both adequate sensitivity during exposure and alkali developability. This solder resist is excellent in dimensional stability against temperature change, and does not exhibit brittleness. In addition, this solder resist enables to obtain a cured product which is excellent in water resistance, electrical insulation, temperature cycle resistance (TCT resistance) and the like. Also disclosed are a dry film having a solder resist layer, a cured product and a printed wiring board. Specifically disclosed is a solder resist containing an acid-modified vinyl ester which is synthesized from an epoxy compound, a phenol compound, an unsaturated monobasic acid and a polybasic acid anhydride, while using a crystalline epoxy resin having a melting point not less than 90°C as at least a part of the epoxy compound and using a compound having a bisphenol S skeleton as at least a part of the phenol compound.