| 摘要 |
<p>PURPOSE:To produce the titled bases low in insulation resistance and water absorption, excellent in flame retardancy and small in warpage after processing into printed circuit boards, by humidifying resin varnish-impregnated bases before the initial stage of their drying. CONSTITUTION:Resin-impregnated bases for laminated sheet are produced by impregnating bases (e.g., kraft paper or glass cloth) with a resin varnish (e.g., phenolic resin varnish or epoxy resin varnish) and drying them by heating. Before the initial stage of the drying, the bases are humidified to a moisture content of about 6-15wt% based on the resin varnish-impregnated bases. Means for humidification may consist of, for example, spraying the bases with mist by means of a sprayer or contacting them with steam before feeding them to a drier or the like.</p> |
