Method of plating plastics

Claim 1

A method for electrodepositing a thin, conductive layer of copper strike on a plastic substrate while avoiding burn-off so as to render it suitable to receive a continuous covering layer of electrolytically deposited copper which method comprises: electrolessly depositing a thin layer of a metal selected from the group consisting of copper, nickel, cobalt and mixtures thereof on a surface of the plastic substrate; positioning the plastic substrate on a supporting member, with the supporting member being in contact at a plurality of spaced apart electrical contact points with the substrate for the passage of electrical current therebetween; immersing the substrate and its support in a copper strike bath in a manner such that all of said electrical contact points formed between said supporting member and said substrate are immersed in said bath, with said bath including from about 10.0 to about 45.0 g/l of copper ions, at least one acid selected from the group consisting of sulfuric acid, fluoroboric acid and sulfamic acid, with the acid being present in an amount sufficient to cause the electroplating bath to have a conductivity ranging from about 0.40 to about 0.60 mhos, and from about 30 to about 105 mg/l of chloride ions; and passing electrical current through the supporting member and the strike bath while said electrical contact points are immersed in said bath so as to cause a strike layer of copper to be electrolytically deposited over the layer of electrolessly deposited metal.

Claim 2

A method for electrodepositing a thin, conductive layer of copper strike on a plastic substrate while avoiding burn-off so as to render it suitable to receive a continuous covering layer of electrolytically deposited copper which method comprises: electrolessly depositing a thin layer of a metal selected from the group consisting of copper, nickel, cobalt and mixtures thereof on a surface of the plastic substrate; positioning the plastic substrate on a supporting member, with the supporting member being in contact at a plurality of spaced apart electrical contact points with the substrate for the passage of electrical current therebetween; immersing the substrate and its support in a copper strike bath in a manner such that all of said electrical contact points formed between said supporting member and said substrate are immersed in said bath, with said bath including from about 10.0 to about 45.0 g/l of copper ions, at least one acid selected from the group consisting of sulfuric acid, fluoroboric acid and sulfamic acid, with the acid being present in an amount sufficient to cause the electroplating bath to have a conductivity ranging from about 0.40 to about 0.60 mhos, and from about 30 to about 105 mg/l of chloride ions; and passing electrical current through the supporting member and the strike bath while said electrical contact points are immersed in said bath so as to cause a strike layer of copper to be electrolytically deposited over the layer of electrolessly deposited metal.