Abstract: A base board for printed circuits prepared by the additive process, obtained by heating under pressure a layer comprising at least one sheet of prepreg comprising a thermosetting resin as impregnant and a layer of composition comprising a semi-cured thermosetting resin and a nitrile rubber, said layer of composition being placed on one or both sides of said prepreg layer to integrate said layers as a finished laminate. This base board is used in the additive process for manufacturing a printed circuit board having favorable properties with strong adhesion between the circuit and the base board without showing any warp or twist.