| 摘要 |
PROBLEM TO BE SOLVED: To obtain a high molecular weight novolak type phenolic resin excellent in handling, heat-resistant properties, curability and carbonization properties, good in the balance between various properties and suitably usable in a wide range of applications. SOLUTION: A novolak type phenolic resin has an amount of unreacted phenol of not greater than 0.5 wt.% and a weight average molecular weight, based on polystyrene as the reference material, of not smaller than 500,000 and can be obtained by reacting a phenol with paraformaldehyde having a purity of not lower than 85% and/or a polyacetal resin without using a catalyst. Preferably, the weight average molecular weight is not smaller than 1,000,000, and not less than 70% bound methylene groups in the phenolic resin are at the ortho-position.
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