Electrochemically roughening aluminum metal sheet
AssigneeAlcan International Limited
InventorsJohn A. Ward, John A. Hunter, Jonathan Ball, Peter K. F. Limbach
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Abstract
A method of electrochemically roughening an aluminum metal sheet for use as a lithographic plate support comprises subjecting the sheet in an electrolyte to an alternating current treatment. Treatment is performed in the presence of at least one added component, present in the sheet or in the electrolyte, selected from Hg, Ga, In, Sn, Bi, Tl, Cd, Pb, Zn and Sb. The added component accelerates the electrograining, so that only 35-75 kCoulombs per square meter of electricity is required.
Claims6
A method of electrochemically roughening an aluminium metal sheet for use as a lithographic plate support, which method comprises subjecting the sheet in an electrolyte to an alternating current treatment to roughen the surface of the sheet, the treatment having a charge input of from about 35 to about 75 kCm.sup.-2 and being performed in the presence of an added component selected from at least one of Hg, Ga, In, Sn, Bi, Tl, Cd, Pb, Zn and Sb, said component being present, in the sheet at a concentration of 0.01-0.5% by weight and/or as a coating on the sheet and/or in combined form in solution in the electrolyte at a concentration of 0.001M to 0.1M, the concentration being effective to increase the rate of electrochemical roughening.
In a method of electrochemically roughening an aluminium metal sheet for use as a lithographic plate support, which method comprises subjecting the sheet in an electrolyte to an alternating current treatment having a charge input of from about 35 to about 75 kCm.sup.-2 to roughen the surface of the sheet, use of an added component selected from Hg, Ga, In, Sn, Bi, Tl, Cd, Pb, Zn and Sb to increase the rate of electrochemical roughening, said added component being present, in the sheet at a concentration of 0.01-0.5% by weight and/or in combined form in solution in the electrolyte at a concentration of 0.001M to 0.1M.
Dependencies are inferred from the claim text.