PURPOSE: To simply and economically obtain the subject resin having a small degree of dispersion at a specific molecular weight by reacting a phenol with an aldehyde under reflux, continuing the reaction under a specific condition, concentrating the reactional product under reduced pressure and subjecting to steam distillation.
CONSTITUTION: First, a phenol is reacted with an aldehyde preferably at 60-110°C usually for 1-50 hours under reflux. Then, after the reaction under reflux is over, the reaction is continued at 120-180°C under normal pressure for 1-12 hours to carry out cleavage reaction and re-bonding reaction of methylene chain. Finally the reactional product is concentrated under reduced pressure at 140-200°C and/or subjected to steam distillation to give the objective resin. A naphthol such as 1-naphthol may be used as a phenol and the molar ratio in the reaction of the naphthol to the phenol is preferably 0.2-2.
HAGIWARA SHINSUKE
SAITO HIROYUKI
