Abstract: An actinic energy ray-curable resin is obtained by reacting an unsaturated monocarboxylic acid (c) with a terminal epoxy group of an epoxy resin having an unsaturated group and a hydroxyl group in its side chains and an epoxy group in its terminal and further reacting a polybasic acid anhydride (d) with the hydroxyl group of the above-mentioned epoxy resin, wherein the above-mentioned epoxy resin is a product of the polyaddition reaction of a reaction product (I) of a polybasic acid anhydride (a) and a compound (b) having at least one unsaturated double bond and one alcoholic hydroxyl group in its molecule, a compound (II) having at least two carboxyl groups in its molecule, and a bifunctional epoxy compound (III), wherein at least either one of the carboxyl group-containing compound (II) and the bifunctional epoxy compound (III) is a compound containing no aromatic ring.

Abstract: An actinic energy ray-curable resin is obtained by reacting (c) an epihalohydrin with hydroxyl groups of a linear epoxy resin (A′) which is a product of the polyaddition reaction of (a) a bifunctional hydrogenated bisphenolic epoxy compound with (b) a compound having at least two carboxyl groups in its molecule to obtain a polynuclear epoxy resin (A″) having epoxy groups in its terminal and side chain and further reacting (d) an unsaturated monocarboxylic acid with an epoxy group of the polynuclear epoxy resin (A″) to introduce a photopolymerizable unsaturated group therein and further reacting (e) a polybasic acid anhydride with a hydroxyl group of the polynuclear epoxy resin to introduce a carboxyl group therein. A photocurable and thermosetting resin composition capable of being developed with an aqueous alkaline solution is obtained by mixing this actinic energy ray-curable resin with a photopolymerization initiator, a diluent, and a polyfunctional epoxy compound.