| 摘要 |
PURPOSE:To facilitate the formation of a resin-impregnated substrate substantial ly free from residual entrapped air by processing a long strip substrate so that its edge may be thicker than the central part and impregnating this sub strate with a resin varnish. CONSTITUTION:A long strip substrate such as a woven cloth or a mat compris ing a glass fiber, a polyester fiber or the like is processed so that its edge may be about 1.2-5 times as thick as the central part. This substrate is then impregnated with a resin varnish (e.g. phenolic resin varnish). In this way, the tension exerted on the central part can be decreased and the impregnatability can be improved, so that a resin-impregnated substrate substan tially free from residual entrapped air can be obtained. A laminated sheet, a printed wiring board or the like excellent in moldability, drillability, etc., can be produced by using this substrate. |
