A photocurable and thermosetting resin composition comprising (A) a
photosensitive prepolymer having a carboxyl group in combination with at
least two ethylenically unsaturated double bonds in its molecule, (B) a
polymerization initiator, (C) a diluent, (D) an oxetane compound having at
least two oxetanyl groups in its molecule, and (E) a curing promotor is
developable with an alkaline solution and can be formulated as a one
package preparation. Such a photocurable and thermosetting resin
composition and a photosensitive dry film prepared by the use thereof are
useful as various resist materials and electrical insulating materials,
particularly as solder resists for printed circuit boards, interlaminar
insulating materials for build-up multi-layer printed circuit boards, and
the like.
