| 摘要 |
<p>PURPOSE:To improve heat resistance, low-temperature resistance, electrical characteristics, mechanical characteristics, wear-resistance property, chemical resistance, radioactive ray resistance, etc., and to prevent curling by applying a specific polyamic aid, curing to a semi-cured state, and then pressing continuously using a metal tube for complete curing. CONSTITUTION:A polyamic acid mixed varnish is prepared by mixing a polyamic acid solution (A) which is obtained by enabling 3,3',4,4'- biphenyltetracarbon acid dianhydride and paraphenirange amine to react each other and a polyamic acid solution (B) which is obtained by enabling pyromellitic dianhydride and 4,4'-diaminodiphenyleter to react each other in the ratio of A/B=55/45-75/25 on a metal foil. This varnish is applied, turned into semi-cured state at a temperature above 80 deg.C and below 250 deg.C and then this semi-cured state varnish is wound on the metal foil 1. Further, this roll- shaped printed circuit board 4 is fixed to a metal frame 2 by a metal bolt 3 and is heated to a temperature above 300 deg.C and below 450 deg.C while applying pressure, thus performing press and heating utilizing the difference in linear expansion coefficients between a metal frame 2, a metal bolt 3 and the printed circuit board for complete curing.</p> |
