To obtain a novolac resin which is useful as a curing agent for epoxy resins and can give a cured product excellent in water resistance, strength, etc., by condensing a specified biphenyl with a phenol in the presence of an acid catalyst.
A compound represented by formula I (wherein X is a halogen, hydroxyl or a lower alkoxyl; and P is H, a halogen, a 1-8C alkyl or an aryl) is condensed with a phenol (e.g. isobutylphenol) in the presence of an acid catalyst (e.g. hydrochloric acid). The reaction temperature is desirably about 40-180°C. The reaction time is desirably about 1-10hr. After the reaction, the reaction mixture is subjected to treatments such as washing with water to obtain a novolac resin represented by formula II (wherein (n) is 0-10 on the average; and R is H, a halogen, a 1-8C alkyl or an aryl). An epoxy resin composition containing the novolac resin as a curing agent is useful in the fields of laminating materials, coating materials, adhesives, resists, etc.
KUBOKI KENICHI
SHIMAMURA YOSHIRO
