Cathode for electrochemical regeneration of permanganate etching solutions
AssigneeAtotech Deutschland GmbH
InventorsReinhard De Boer, Sebastian Dunnebeil
Life of this patent
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Abstract
In order to regenerate permanganate solutions being utilized for the etching and roughening of plastics surfaces electrolytic methods are known. Though relatively small quantaties of by-products are produced with these methods as compared to chemical regeneration methods, large quantaties of manganese dioxide are produced when printed circuit boards are treated. In order to avoid formation of manganese dioxide during the regeneration method a novel cathode 2 has been found which is provided with a porous, electrically nonconducting layer 7 on the cathode body 3. The layer 7 preferably consists of a plastics material being resistant to acid and/or alkali.
Claims14
Cathode for an electrochemical arrangement for regenerating permanganate etching solutions, wherein the cathode (2) is provided with a porous, electrically nonconducting layer (7) on the surface thereof.
Cathode according to any of the preceding claims, wherein the layer (7) comprises a plastics material resistant to acid and/or alkali.
Cathode according to any of the preceding claims, wherein the layer (7) comprises a fabric (4,5) fitting firmly to the cathode (2).
Cathode according to any of the preceding claims, wherein the layer (7) comprises a material, selected from the group comprising polyalkylene und polyperhalogenalkylene.
Cathode according to any of the preceding claims, wherein the layer (7) is composed of a material, selected from the group comprising polypropylene, high density polyethylene and polytetrafluor ethylene.
Cathode according to any of the preceding claims, wherein additionally an insoluble layer (6) is adsorbed to the surface of the cathode (7), the layer (6) at least predominantly containing manganese having an oxidation number of +IV.
Cathode according to any of the preceding claims, wherein the cathode (2) is formed as a rod.
Method for the manufacture of a cathode for an arrangement for electrochemically regenerating permanganate etching solutions, wherein
- a. a cathode body (3) is provided with a porous, electrically nonconducting layer (7);
- b. the cathode body (3) provided with the layer (7) is brought into contact with an alkaline permanganate solution containing manganate;
- c. an anode (1) is brought into contact with the alkaline permanganate solution containing manganate;
- and
- d. by means of a electric current source an electric current is produced in a current circuit being formed by the cathode (2) and the anode (1) in such a way that an insoluble layer (6) is formed on the surface of the cathode (2), the layer (6) at least predominantly containing manganese having an oxidation number of +IV.
Dependencies are inferred from the claim text.