| 摘要 |
<p>A process for the production of a phenolic resin modified with a liquid polybutadiene being useful as an impregnating varnish in the production of a copper-clad laminate for a printed circuit, which comprises preparing an adduct of a liquid polybutadiene having a number average molecular weight of 150 to 5,000 with an alpha , beta -unsaturated dicarboxylic acid or its anhydride, subjecting the adduct to an addition reaction with one or plurality of phenols in the presence of an acid catalyst to obtain a composition and reacting the composition with formaldehyde in the presence of a basic catalyst.</p> |
