TREATING ALUMINUM OXIDE LAYER WITH AQUEOUS HEXAMETAPHOSPHATE SOLUTION FOR PRODUCING PRINTING PLATE SUPPORT

摘要

A process for manufacturing materials in the form of sheets, foils or webs comprising chemically, mechanically and/or electrochemically roughened and anodically oxidized aluminum or one of its alloys, wherein the resultant aluminum oxide layers are posttreated with an aqueous solution containing phosphoroxo anions, is performed such that a post-treatment of the aluminum oxide layers is effected by immersion in an aqueous solution containing hexametaphosphate anion. In a preferred embodiment, the aqueous solution is adjusted to a pH of 1 to 5 by addition of an acid. The resulting materials, which have reduced adsorption properties, are preferably employed as support materials for offset printing plates.