Abstract: The present invention provides a radically polymerizable curable resin obtained by modifying an epoxy resin by reacting a phenol compound having an alcoholic hydroxyl group; and an unsaturated monobasic acid, to the epoxy resin having two or more epoxy groups in a molecule. The epoxy resin is reacted with the phenol compound and the unsaturated monobasic acid. The curable resin is subjected to polymerization curing with heat or light to form a cured product having excellent heat resistance, moisture resistance, and adhesion to substrates. The present invention also provides a curable resin composition containing the curable resin, as well as an alkaline-developable curable resin capable of forming a coating layer having excellent tack-free property, quick developability and excellent properties of cured layer.

Abstract: The present invention provides a production method for a photo-sensitive resin, characterized in reacting a difunctional epoxy resin (B) having two epoxy groups in a molecule with carboxyl groups contained in a resin (A) having two or more (meth)acryloyl groups and at least one carboxyl group in a molecule. Since the photo-sensitive resin prepared by extending the resin (A) to a high molecular weight linearly via the difunctional epoxy resin (B) is obtained, a resist layer having an excellent tack-free property can be formed. Further, a resist layer irradiated with rays through a patterning film can be developed rapidly and correctly in an alkaline aqueous solution. Accordingly, it has been possible to provide the high-performance liquid photo-sensitive resin compositions useful for a solder resist used for producing printed circuit boards and for an electroless plating resist or useful for producing black matrices and color filters for liquid crystal displays.