Process for producing phenolic novolak

摘要

A phenolic novolak having the contents of a monomeric phenol and a dimeric phenol and a degree of dispersion controlled can be obtained in high yield by a process for production of a phenolic novolak having a step of conducting a heterogeneous reaction of a phenol and an aldehyde in the presence of a phosphoric acid and an unreactive oxygen-containing organic solvent as a reaction cosolvent.