Base laminate for mfr. of printed circuits - comprises core of mineral filler compounded with binder, sandwiched between impregnated glass-fibre plies and/or copper foil

摘要

Base material used in mfr. of printed circuits by subtractive, semi-additive, or additive process, for insulating intermediate plies, comprises ac ore of (non)conductive mineral filler(s) mixed and calendered with binder(s). The resulting core ply is sandwich-laminated between paper/glass-fibre-fleece/glass-fibre-textile plies which are impregnated with an excess of epoxy and/or phenolic resin. The resin content of the core is relatively low. A variant calls for a further ply viz. a Cu-foil, to be laminated on one or both sides of the resulting laminated whilst a second variant claims laminating the Cu-foil(s) directly onto the core, without any intermediate ply (plies).