| 摘要 |
Process for etching a nickel-polyester layered offset plate, which is made by electroless nickel-plating of polyester and subsequently coated on the nickel-layer by a photoresist layer. After exposure of the photoresist layer under a transparent master and development of the offset-plate, the offset-plate is etched by an aqueous etching solution containing copper(II) ions, as the only etching agent together with Cl- ions. An offset printing plate is prepared from the etched nickel-polyester layered plate. The nickel layer of the nickel-polyester layered plate is etched with the aqueous etching solution. The etching solution additionally contains: (a) a salt which is inert as against the nickel-polyester layered plate, or 10 to 40 weight percent of an organic solvent, which is miscible or nonmiscible with water and which is inert as against the nickel-polyester layered plate, and 60 to 90 weight percent of de-ionized water; and (b) a wetting agent or pyridine. Subsequent to the etching process, the photoresist is removed and the printing parts (i.e., polyester parts) of the nickel-polyester layered plate are oleophilized with an oleophilization agent which is an aliphatic acid, aromatic acid, acid chloride or acid anhydride. The non-etched portion of the nickel layer of the nickel-polyester layered plate is hydrophilized with a solution of a complexing agent for nickel ions, which opposite the solvating sphere of the nickel complex has only hydrophilic groups. The oleophilization of the polyester layer and hydrophilization of the nickel layer can be executed separately in two process steps or executed concurrently in one process step, using one solution containing the oleophilization agent and the complexing agent. The aqueous etching solution does not contain a side-wall protective additive.
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