Method for depositing a first metallic layer onto non-conductive polymers
View Patent ↗The present invention relates to the etching, activation and deposition of a first metal or metal alloy layer onto non-conductive polymers. The non-conductive polymer is etched with an aqueous solution comprising 0.75 to 3.6 g/l permanganate ions in 60 to 80 vol.-% sulfuric acid, activating with a solution comprising a noble metal and depositing a first metal or metal alloy by immersion-type or electroless (autocatalytic) plating. The first metal or metal alloy layer obtained has a high adhesion on the non-conductive polymer and serves as a plating base for electroplating further metal and/or metal alloy layer(s) thereon.
1. A method for depositing a first metal or metal alloy layer onto a non-conductive polymer comprising, in this order, the steps of
(i) providing a non-conductive polymer,
(ii) contacting the non-conductive polymer with an etching solution comprising 0.75 to 3.6 g/l permanganate ions in 60 to 80 vol.-% sulfuric acid,
(iii) contacting the etched non-conductive polymer with an activator solution comprising a noble metal and
(iv) depositing a first metal or metal alloy layer by a wet-chemical method onto the activated non-conductive polymer,
wherein the etching solution further comprises phosphoric acid and the density of the etching solution is adjusted with the phosphoric acid to a range of 1.70 to 1.82 g/ml.
2. The method for depositing a first metal or metal alloy layer onto a non-conductive polymer according to claim 1 wherein the non-conductive polymer is selected from the group consisting of acrylonitrile-butadiene-styrene copolymer, polycarbonates, acrylonitrile-butadiene-styrene copolymer-polycarbonate blends, polyamide and epoxy resins.
3. The method for depositing a first metal or metal alloy layer onto a non-conductive polymer according to claim 1 wherein the temperature of the etching solution ranges from 10 to 40° C.
4. The method for depositing a first metal or metal alloy layer onto a non-conductive polymer according to claim 1 wherein the source of permanganate ions is selected from the group consisting of alkaline- and alkaline earth-metal permanganates.
5. The method for depositing a first metal or metal alloy layer onto a non-conductive polymer according to claim 1 wherein the source of permanganate ions is selected from the group consisting of sodium permanganate and potassium permanganate.
6. The method for depositing a first metal or metal alloy layer onto a non-conductive polymer according to claim 1 wherein the noble metal is selected from the group consisting of silver, gold, ruthenium, rhodium, palladium, osmium, iridium, platinum and mixtures thereof.
7. The method for depositing a first metal or metal alloy layer onto a non-conductive polymer according to claim 1 wherein the activator solution is an aqueous solution comprising palladium ions.
8. The method for depositing a first metal or metal alloy layer onto a non-conductive polymer according to claim 7 wherein the concentration of palladium ions ranges from 10 to 500 mg/l.
9. The method for depositing a first metal or metal alloy layer onto a non-conductive polymer according to claim 1 wherein the activator solution is an aqueous solution comprising colloidal palladium.
10. The method for depositing a first metal or metal alloy layer onto a non-conductive polymer according to claim 9 wherein the concentration of the colloidal palladium ranges from 50 to 500 mg/l.
11. The method for depositing a first metal or metal alloy layer onto a non-conductive polymer according to claim 1 wherein the first metal layer is deposited by electroless autocatalytic plating or immersion-type plating.
12. The method for depositing a first metal or metal alloy layer onto a non-conductive polymer according to claim 1 wherein the first metal or metal alloy layer is selected from copper, nickel and nickel alloys.