LIQUID PHENOL NOVOLAC RESIN AND CURING AGENT,FOR SEMICONDUCTOR SEALING

摘要

PROBLEM TO BE SOLVED: To obtain a liquid phenol novolac resin which can exhibit excellent flowability, low water absorptivity, and heat resistance by bridging a skeleton component being phenol and o-substituted phenol with methylene and/or hydroxyphenylmethylene groups. SOLUTION: Formalin and at least either of o- and p-hydroxybenzaldehyde are used as a bridging agent for phenol and phenol having a 1-4C alkyl in the ortho position (e.g. o-cresol) or o-allylphenol. The compositional rate of the o-substituted phenol in the resin is 5-95 mol% based on the entire skeleton component, and that of the hydroxyphenylmethylene groups is at most 70 mol% based on the entire bridging component. The bridging agent and an at least three molar times of a phenolic compound are reacted with each other at 50-200 deg.C in the presence of an acid catalyst such as a-n acid to obtain a liquid phenol novolac resin having a number-average molecular weight of at most 400. This resin can be desirably used as a curing agent for an epoxy resin or an epoxidized phenol novolac resin for e.g. semiconductor sealing.