Abstract: A process for producing a printed circuit board characterized by forming a thermosetting resin layer on internal walls of through holes before an electroless plating treatment can produce printed circuit boards having high reliability without causing blow-holes on the through hole walls.

Abstract: A process for preparing a chemically platable thermosetting powder coating characterized by preliminarily kneading a composition comprising 3 to 50% by weight of a thermosetting resin, 5 to 60% by weight of an inorganic filler and up to 80% by weight of a rubber component comprising at least 10% by weight of a rubber having ethylenic double bonds and polar groups in the molecule, the amount of which rubber component constitutes the total amount of rubber component in the final powder coating, the rubber component content of the composition to be subjected to the preliminary kneading being at least twice the rubber component content of the final powder coating, said composition being heated at a temperature of at least the melting point of the thermosetting resin at least once during the course of the preliminary kneading, thereby to effect efficient dispersion of the components.

Abstract: A method of improving adhesion between the surface of a substrate and a metal deposit electrolessly plated thereon by forming a novel adhesive material layer comprising (A) a rubber material and (B) a thermosetting resin which is present in a proportion defined by the formula 20.ltoreq.(B)/(A)+(B).ltoreq.85 volume %. In the adhesive layer the thermosetting resin is dispersed, in the form of substantially spherical particles of 0.5 to 15.mu., in the continuous phase of the rubber material. The method is useful for producing printed circuit boards having a high precision and high accuracy pattern circuit. Further, the method is extremely advantageous when it is applied to the so-called photo-forming process since disappearance of the catalyst nuclei on the circuit pattern image can be eliminated.