Etching of plastic using acidic solutions containing trivalent manganese
View Patent ↗A method of preparing a solution capable of etching a platable plastic. The method comprises the steps of: (a) providing an electrolyte comprising a solution of manganese(II) in a solution of 9 to 15 molar sulfuric acid or phosphoric acid to an electrolytic cell; (b) applying a current to the electrolytic cell, wherein the electrolytic cell comprises an anode and a cathode; and (c) oxidizing the electrolyte to form manganese(III) ions, wherein the manganese(III) ions form a metastable sulfate complex. Thereafter, a platable plastic may be immersed in the metastable sulfate complex for a period of time to etch the platable substrate prior to subsequent plating steps.
1. A method of preparing a solution capable of etching a plastic substrate, the method comprising the steps of:
(a) providing an electrolyte comprising manganese(II) ions and at least 9 molar sulfuric acid to an electrolytic cell;
(b) applying a current to the electrolytic cell, wherein the electrolytic cell comprises an anode and a cathode;
(c) oxidizing the electrolyte to form manganese(III) ions, wherein the concentration of manganese (II) ions and manganese(III) ions exceeds the concentration of permanganate ions; and
(d) etching the plastic substrate with the electrolyte.
2. The method of claim 1 , wherein the plastic substrate comprises acrylonitrile-butadiene-styrene or acrylonitrile-butadiene-styrene/polycarbonate.
3. The method of claim 1 , wherein the source of manganese(II) is from the group consisting of manganese sulfate, manganese carbonate and manganese hydroxide.
4. The method of claim 1 , wherein the anode comprises a material selected from the group consisting of platinum, platinized titanium, iridium oxide coated titanium, and niobium.
5. The method of claim 1 , wherein the cathode comprises a material selected from the group consisting of platinum, platinized titanium, iridium oxide coated titanium, and niobium.
6. The method of claim 1 , wherein the temperature of electrolyte is between 50 and 70° C.
7. The method of claim 1 , wherein the step of oxidizing the electrolyte includes agitating the electrolyte.
8. The method of claim 1 , wherein the electrolytic cell is divided.
9. The method of claim 1 , wherein the electrolytic cell is not divided.
10. A method of preparing a solution capable of etching a plastic substrate, the method comprising the steps of:
(a) providing an electrolyte comprising manganese(II) ions and at least 9 molar sulfuric acid to an electrolytic cell;
(b) applying a current to the electrolytic cell, wherein the electrolytic cell comprises an anode and a cathode; and
(c) oxidizing the electrolyte to form manganese(III) ions, wherein after oxidizing the electrolyte to form manganese(III) ions, the concentration of mangariese(III) ions exceeds the concentration of permanganate ions; and
(d) etching the plastic substrate with the electrolyte.
11. The method of claim 10 , wherein the plastic substrate comprises acrylonitrile-butadiene-styrene or acrylonitrile-butadiene-styrene/polycarbonate.
12. The method of claim 10 , wherein the source of manganese(II) is from the group consisting of manganese sulfate, manganese carbonate and manganese hydroxide.
13. The method of claim 10 , wherein the anode comprises a material selected from the group consisting of platinum, platinized titanium, iridium oxide coated titanium, and niobium.
14. The method of claim 10 , wherein the cathode comprises a material selected from the group consisting of platinum, platinized titanium, iridium oxide coated titanium, and niobium.
15. The method of claim 10 , wherein the temperature of electrolyte is between 50 and 70° C.
16. The method of claim 10 , wherein the step of oxidizing the electrolyte includes agitating the electrolyte.
17. The method of claim 10 , wherein the electrolytic cell is divided.
18. The method of claim 10 , wherein the electrolytic cell is not divided.
19. A method of preparing a solution capable of etching a plastic substrate, the method comprising the steps of:
(a) providing an electrolyte comprising manganese(II) ions and at least 9 molar sulfuric acid to an electrolytic cell;
(b) applying a current to the electrolytic cell, wherein the electrolytic cell comprises an anode and a cathode;
(c) oxidizing the electrolyte to form manganese(III) ions, wherein after the step of oxidizing the electrolyte to form manganese(III) ions, the electrolyte remains at least substantially free of permanganate ions; and
(d) etching the plastic substrate with the electrolyte.
20. The method of claim 19 , wherein the plastic substrate comprises acrylonitrile-butadiene-styrene or acrylonitrile-butadiene-styrene/polycarbonate.
21. The method of claim 19 , wherein the source of manganese(II) is from the group consisting of manganese sulfate, manganese carbonate and manganese hydroxide.
22. The method of claim 19 , wherein the anode comprises a material selected from the group consisting of platinum, platinized titanium, iridium oxide coated titanium, and niobium.
23. The method of claim 19 , wherein the cathode comprises a material selected from the group consisting of platinum, platinized titanium, iridium oxide coated titanium, and niobium.
24. The method of claim 19 , wherein the temperature of electrolyte is between 50 and 70 ° C.
25. The method of claim 19 , wherein the step of oxidizing the electrolyte includes agitating the electrolyte.
26. The method of claim 19 , wherein the electrolytic cell is divided.
27. The method of claim 19 , wherein the electrolytic cell is not divided.