PURPOSE: To enable the formation of electrolytic copper foil having a gold hot elongation rate by electrolyzing an electrolyte, specific volumetric % of which is continuously subjected to an active carbon treatment, within a specific period of time.
CONSTITUTION: The electrolyte is introduced in the amt. of 60vol.%, from an electrolyte supply line 1 into an active carbon packed column 2 and is subjected to the active carbon treatment. The electrolyte within 20 minutes after the treatment is joined with the untreated electrolyte and is introduced into an electrolytic cell 3 where electrolytic copper foil 6 is deposited on a cathode by using a cathode drum 4 and an insoluble anode 5. This copper foil has ≥8.5% hot elongation rate at 180°C. The above-mentioned deposition is estimated to occur in that the tervalent iron ions and hexad chromium ions contained in the electrolyte are reduced by the cathode and that the most thereof forms the foil consisting of the copper alone.
NABEKURA KAZUYOSHI
HIRASAWA YUTAKA
FUJIKI MAKOTO
| JPS6152387A | 1986-03-15 |