| 摘要 |
PURPOSE:To obtain excellent dimensional stability and impregnation properties of a plating solution by enabling low pressure lamination molding and preventing the generation of voids, by making the number of bubbles contained by a resin- impregnated base material less than 500 pieces per square inch. CONSTITUTION:Impregnation of a base material with resin is performed under depressurization of a varnish tank by depressurizing the same or depressurizing the same after pressurizing the same by passing the base material between an upper and lower two rolls arranged within the same. As the impregnation is performed under pressurization or depressurization, involving-in of bubbles to the base material in the inside of the varnish tank can be reduced. After the base material has been impregnated with the resin, the resin-impregnated base material whose containing bubbles are less than 500 pieces per square inch is obtained by drying the same. Then necessary sheets of the resin- impregnated base material are piled up, metallic foils are arranged on both sides or one side of them, a plurality of sets of which is combined by making the foregoing sheets into the set, placed between an upper and lower two sheets of moving belts and laminated board or multi-layer board is obtained.
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