ELECTROCHEMICAL ROUGHENING OF ALUMINUM FOR PRINTING PLATES IN HYDROCHLORIC ACID AND HYDROFLUORIC ACID

摘要

The invention relates to a process for the electrochemical roughening of a plate of aluminum or an alloy thereof which is useful for a printing plate support, comprising the steps of (A) immersing the plate in an aqueous mixed electrolyte solution containing (i) from about 0.5 to 10% by weight HCl and (ii) a further inorganic acid comprising HF, such that said mixed electrolyte solution contains from about 0.05 to 5% by weight of HF; and (B) applying an alternating current to the plate to produce a uniformly roughened offset printing plate support. The very uniformly roughened support materials are used in the production of offset printing plates.