A novolak resin including a partial structure represented by —C(CF.sub.3)H—. In addition, there are provided a photosensitive resin composition containing the above-described novolak resin and a photosensitizing agent. In addition, there is provided an epoxy resin having a partial structure represented by —C(CF.sub.3)H—. In addition, there is provided a curable resin composition containing the novolak resin or the epoxy resin. In addition, there is provided a cured substance obtained by curing the composition. In addition, there is provided a production method for a novolak resin, including reacting an aromatic compound with fluoral in a presence of an acid catalyst to produce a novolak resin having a partial structure represented by —C(CF.sub.3)H—. Further, there is provided a production method for an epoxy resin, including an epoxidation step of reacting a novolak resin having a partial structure represented by —C(CF.sub.3)H— with epihalohydrin in a presence of a base.

A curable composition including a silicone copolymer, a fluoropolyether group-containing compound, and a matrix-forming composition, wherein the silicone copolymer has two or more crosslinkable groups; and the crosslinkable group is a group containing a carbon-carbon double bond, a carbon-carbon triple bond, a cyclic ether group, a hydroxyl group, a thiol group, an amino group, an azide group, a nitrogen-containing heterocyclic group, an isocyanate group, a halogen atom, a phosphoric acid-containing group, or a silane coupling group, or a precursor group thereof. Also disclosed is a film formed from the curable composition, and an article including a substrate and a layer on a surface of the substrate formed from the curable composition.

Provided is an epoxy resin composition that has excellent electric characteristics (particularly low dielectric tangent), and that can achieve high adhesive strength to metal. Specifically, provided is an epoxy resin composition comprising an active ester compound and an epoxy resin having a specific structure.