Process for the electrochemical roughening of aluminum for use as printing plate supports, in an aqueous mixed electrolyte

US4618405A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Dieter Mohr · Appenheim, DE
• Werner Frass · Wiesbaden, DE

Key dates

• Filing date: Apr 23, 1985
• Grant date: Oct 21, 1986
• Expiry date: Apr 23, 2005

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C25F3/04
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

Disclosed is a process for electrochemically roughening aluminum or aluminum alloys for use as printing plate supports, in an aqueous mixed electrolyte solution containing hydrochloric acid (HCl) and, as an additional inorganic electrolyte, at least one compound selected from the group consisting of condensed phosphoric acids, amidosulfonic acid, and the water-soluble alkali metal salts and ammonium salts thereof. In particular, the solution contains from 0.5 to 10% by weight of HCl and from 0.05 to 5.0% by weight of the additional inorganic electrolyte (for example, diphosphoric acid or polyphosphoric acid). The support materials which are particularly uniformly roughened are employed in the production of offset-printing plates.