Process for treating lithographic printing forms and lithographic printing forms produced thereby
AssigneeHoechst Aktiengesellschaft
InventorsAndreas Elsaesser, Michael Brenk
Life of this patent
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Abstract
Grained, anodized and hydrophilized lithographic printing plates which have a negative or positive working radiation-sensitive coating, are exposed and are developed in an aqueous alkaline solution, are subjected, after hydrophilization, to a treatment with a salt solution containing divalent or polyvalent cations in a concentration of not less than 0.02 mol/l, thereby minimizing degradation of the plate and contamination of the printing forms and the development apparatus.
Claims21
A process for treating grained, and anodized lithographic printing plates so as to reduce the amount of degradation of the metal oxide layer formed during the anodization, comprising the steps of hydrophilizing the plate with polyvinylphosphonic acid and treating the hydrophilized plate with a salt solution containing divalent or polyvalent cations in a concentration of not less than 0.02 mol/l, wherein the salt solution contains at least one salt selected from the group consisting of MgCl.sub.2, Mg(NO.sub.3).sub.2, CaCl.sub.2, Ca(NO.sub.3).sub.2, Ca acetate, SrCl.sub.2, Sr laevulinate, BaCl.sub.2, Ba(NO.sub.3).sub.2, ScCl.sub.3, Sc.sub.2 (SO.sub.4).sub.3, LaCl.sub.3, La(NO.sub.3).sub.3, TiCl.sub.3, VSO.sub.4, CrCl.sub.2, MnBr.sub.2, NiCl.sub.2, CuCl.sub.2, ZnSO.sub.4, AlCl.sub.3, SnCl.sub.2, and Pb acetate.
Dependencies are inferred from the claim text.