| abstract |
Provided are an active ester resin capable of having low cure shrinkage and forming a cured product having a low dielectric loss tangent, a curable resin composition including the ester resin, a cured product of the resin composition, a printed wiring board, and a semiconductor encapsulating material. The active ester resin includes a product of reaction of essential raw materials including: a phenolic hydroxyl group-containing compound (A); a polynaphthol resin (B) having a molecular structure in which naphthol compound (b) moieties are linked with an aromatic ring- or cyclo ring-containing structural moiety (α); and an aromatic polycarboxylic acid or an acid halide thereof (C). Also provided are a curable resin composition including the ester resin, a cured product of the resin composition, a printed wiring board, and a semiconductor encapsulating material. |