| 摘要 |
PURPOSE:To obtain a printing plate capable of providing a uniform form surface, free of contamination and having excellent durability in printing, by chemically etching a surface of an aluminum plate with an aqueous solution containing a mineral acid and an aluminum salt of a mineral acid, said salt being in a concentration of 40-95 wt% based on the saturation concentration thereof, to obtain a center line average roughness of 0.3-1.3mum. CONSTITUTION:An aluminum plate subjected to a cleaning treatment if required, is chemically etched with an aqueous solution containing a mineral acid and an alumi num salt of a mineral acid. The mineral acid may be hydrochloric acid, sulfuric acid or the like, with hydrochloric acid being particularly preferable. As the salt, aluminum chloride is particularly preferred, and the salt must be contained in the solution in a concentration of 40-95 wt% based on the saturation concentration thereof. A center line surface roughness of 0.3-1.3 mum is profitably obtained under the treating conditions of a temperature of 20-100 deg.C and a treating time of 1-120 sec. Since smut is formed on the surface of the aluminum plate thus chemically etched, a desmutting treatment is performed. Where the aluminum plate is served is production of a palnographic plate with high durability in printing, the plate thus treated is further subjected to an anodic oxidation treatment by a method ordinarily used in the field. |
