| 摘要 |
PURPOSE:To contrive prevention of contamination in printing due to a silicone oil at the time of PPC plate making, by preliminarily treating the surface of an original plate with a treating liquid containing a constituent for providing a hydrophilic property by strongly reacting with a constituent in an aqueous treating liquid containing a chloride of a bivalent or higher valent metal, and after drying, treating the surface with an ordinary treating liquid. CONSTITUTION:When treating the surface of an original plate with an aqueous treating liquid containing a ferrocyanide, a phosphate and an organic acid as main constituents, an aqueous treating liquid containing a chloride of a bivalent or higher valent metal is preliminarily applied to the surface, followed by drying. The metal chloride contained in the first treating liquid is preferably aluminum chloride, ferric chloride or zinc chloride, and is used at a concentration of 1-10wt% in the liquid. An alcohol, a surfactant or the like may be added to the first treating liquid to promote wetting of the surface of the plate. The ferrocyanide may be sodium ferrocyanide, potassium ferrocyanide, ammonium ferrocyanide or the like. The phosphate may be any one of primary to tertiary ammonium salts of phosphoric acid, or the like. The organic acid may be polybasic, adipic acid, malic acid, citric acid or the like. |
