Process for the one-stage anodic oxidation of aluminum bases for offset printing plates

Abstract From the Canadian patent

A process is disclosed for the production of bases for offset printing plates in the form of sheets foils or webs made of roughened aluminum or one of its alloys, which is carried out in an anodic oxidation stage, i.e. in an aqueous electrolyte which contains phosphorus-containing anions. In the procedure an, electrolyte containing dissolved phosphoroxo anions with the exception of aqueous H3PO4, is employed and, the treatment is carried out for a period of about 1 to 90 seconds, at a voltage between about 10 and 100 volts and at a temperature of about 10 to 80 °C. The electrolyte is in particular, a salt of an, oxyacid of phosphorus such as Na3PO4 or K3PO4. Hydrophilization of the base can …