| 摘要 |
PURPOSE:To produce the titled resin useful as a sealing agent for electrical devices which can form a cured product excellent in heat resistance and mechanical strength, by polycondensing o-cresol with an aldehyde in the presence of an acidic catalyst in a specified organic solvent. CONSTITUTION:A high-MW cresol novolak resin of a softening point >=145 deg.C is produced by polycondensing o-cresol with an aldehyde (e.g., paraformaldehyde) in the presence of an acidic catalyst (e.g., sulfuric acid) in a solvent selected from among 3-12C aliphatic alcohols, 3-6C glycol ethers, benzyl alcohol and 2-6C aliphatic carboxylic acids (e.g., methyl cellosolve, n-butanol or acetic acid). This resin is excellent in solubility in organic solvents such as aliphatic alcohols, ketones, esters, and glycol ethers. When it is cured by the addition of an epoxy resin or a polyisocyanate, it can form a cured product rich in heat resistance and excellent in mechanical strength, so that it is useful as a sealing agent for electrical devices or an aircraft structural material.
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