Phenolic resin, curable resin composition, and cured product thereof

The present invention addresses the problem of providing a phenolic resin, a composition, and a cured product thereof, which have excellent fluidity and excellent balance of thermal modulus, low hygroscopicity, and dielectric properties of a cured product thereof, and which can be suitably used in semiconductor sealing materials and the like. A reaction product of a monohydric phenol compound and an aromatic carboxylic acid having a hydroxyl group, the reaction product being characterized in that the total peak area of an ester compound represented by formula (1) and a ketone compound represented by formula (2) in GPC measurement is 70-99%. (In the formula, each of R1-R17 independently represents a hydrogen atom, an alkyl group having 1-4 carbon atoms, or an alkoxy group having 1-4 carbon atoms. ) 本发明的课题在于，提供：流动性优异、且固化物的热时模量、低吸湿性、介电特性的均衡性优异、能适合用于半导体封装材料等的酚醛树脂、组合物、和其固化物，本发明提供一种酚醛树脂，其特征在于，其为一元酚化合物与具有羟基的芳香族羧酸的反应物，GPC测定中下述式(1)所示的酯化合物与下述式(2)所示的酮化合物(2)的总计的峰面积为70～99％。(式中，R1～R17各自独立地为氢原子、碳原子数1～4的烷基或碳原子数1～4的烷氧基。)