Two-stage process for the production of anodically oxidized aluminum planar materials and use of these materials in manufacturing offset-printing plates

US4566952A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Gerhard Sprintschnik · Taunusstein, DE
• Walter Niderstatter · Eltville am Rhein, DE
• Joachim Stroszynski · Wiesbaden, DE

Key dates

• Filing date: Mar 30, 1984
• Grant date: Jan 28, 1986
• Expiry date: Mar 30, 2004

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S205/921
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

Disclosed is a process for the production of a material in the form of a plate, a foil or a strip, from aluminum or an alloy thereof, which has been chemically, mechanically and/or electrochemically roughened. The process comprises a two-stage oxidation involving a first stage (a) which is performed in an aqueous electrolyte having from about 60 to 180 g/l of phosphoric acid, at a temperature of the electrolyte bath of about 47.degree. to 70.degree. C. and at a voltage of about 36 to 80 V and a second stage (b) which is performed in an aqueous electrolyte having from about 60 to 300 g/l of sulfuric acid, at a temperature of the electrolyte bath of about 30.degree. to 65.degree. C. and at a voltage of about 15 to 35 V. Also disclosed is an offset-printing plate, having a radiation-sensitive coating and a support material produced by the process described above.