| 摘要 |
PURPOSE:To prevent voids and craters from developing, enhance edgewise insulation resistance and at the same time peel strength of metal foil by a method wherein base material is impregnated with resin in an atmosphere, the absolute humidity of which is below a specified value. CONSTITUTION:Base material is impregnated with resin in the atmosphere, the absolute humidity of which is 0.015kg/m<3>. As a result, the edgewise insulation resistance of the resultant base material is high and neither void in its interior nor crater in its surface exists. In addition, the curing characteristics such as the gel time, the maximum exothermic temperature and the like of the resin during the manufacture of a board material are also improved. Especially as for a board material, to the surface of which metal foil is laminated by molding, no shrinkage mark develops in the metal foil and accordingly the peel strength of the metal foil is enhanced. Furthermore, the base material is preferably impregnated with the resin in such a manner that the resin content of the resultant printed-wiring board material lies within the range of 30-80wt%. If the resin content is less than 30wt%, blister tends to develop in the base material during the curing of the resin. If the resin content is more than 80wt%, the base material warps in a large scale when it is etched. |
