Metallisable surface layer for printed circuit boards - which eliminates oxidative etching of the base material, comprises copolymer of organic acid (ester) and e.g. acid amide

摘要

A metallisable surface layer for printed circuit boards contains a copolymer of an organic acid and/or ester, together with an acid amide and/or amino-ester. Pref. the organic acid is (meth)acrylic, crotonic or semi-esters of itaconic, maleic or fumaric acid. The ester is formed from these acids and 1-12C alcohols. Oxidative etching and roughening of the board, e.g. with K dichromate/H2SO4 mixt., fluoboric acid or gas contg. SO3 is eliminated, together with associated problems of process control and pollution. The layer provides sites for metal adhesion throughout the full thickness, so that metal bonding occurs in holes subsequently formed in the board.