| 摘要 |
PROBLEM TO BE SOLVED: To obtain a liquid phenol novolac resin having excellent flowability, low water absorptivity, and heat resistance by reacting phenol (A) and a phenol (B) compound having an alkyl of a specified number of carbon atoms/an allyl in the ortho positions, formaldehyde (C) and/or o-hydroxybenzaldehyde p- hydroxybenzaldehyde (D). SOLUTION: Phenol A and a phenol compound B are used in a ratio B/(A+B) of 5-95 mol%, and formaldehyde C and compound B acting as a bridging groups are used in a ratio D/(C+D) of at most 70 mol%. The phenol compound having a 1-4C alkyl is exemplified by o-cresol, and the phenol compound having a 1-4C alkyl is exemplified by o-allylphenol. The catalyst used is an acid such as an organic acid such as oxalic acid or p-toluenesulfonic acid or an inorganic acid. The amount of the acid used is 0.01-1 wt.% based on the phenolic compound.
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