Aqueous alkaline solution for developing offset printing plates
AssigneeImation Corp.
InventorMario Piro
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Abstract
The present invention relates to an aqueous alkaline developing solution comprising an alkaline mixture of an alkali metal silicate and/or an alkali metal metasilicate, wherein the M.sub.2 O/SiO.sub.2 molar ratio of said alkaline mixture is in the range of from 0.5 to 1.2, the total content of said alkaline mixture being in the range of from 6 to 15% by weight of the total developing solution, and wherein said developing solution comprises a non-ionic surfactant and at least another surfactant selected from the group consisting of anionic surfactants and amphoteric surfactants. An alkali metal hydroxide can be optionally added to the alkaline mixture. Also claimed is the concentrated developing solution to be diluted to the desired strength.
Claims27
A method for developing a printing plate comprising quinonediazide Or diazo compounds in a photosensitive layer, said method comprising imagewise exposing said printing plate, and then washing off more soluble areas of said photosensitive layer in an aqueous alkaline developing solution, wherein said aqueous alkaline developing solution comprising an alkaline composition of at least one compound selected from the group consisting of alkali metal silicate and alkali metal metasilicate, wherein the M.sub.2 O/SiO.sub.2 molar ratio of said alkaline composition is in the range of from 0.5 to 1.2, the total content of said alkaline composition being in the range of from 6 to 15% by weight of total developing solution, and wherein said developing solution comprises a non-ionic surfactant and at least another surfactant selected from the group consisting of anionic surfactants and amphoteric surfactants.
A method for developing a printing plate comprising quinonediazide or diazo compounds in a photosensitive layer, said method comprising imagewise exposing said printing plate, and then washing off more soluble areas of said photosensitive layer in an aqueous alkaline developing solution, wherein said aqueous alkaline developing solution is made from a concentrated aqueous alkaline developing solution by diluting said concentrated solution with water in a mixing ratio of 1 to 3 to form a ready-to-use aqueous alkaline developing solution comprising an alkaline composition of at least one compound selected from the group consisting of alkali metal silicate and alkali metal metasilicate, wherein the M.sub.2 O/SiO.sub.2 molar ratio of said alkaline composition is in the range of from 0.5 to 1.2, the total content of said alkaline composition being in the range of from 6 to 15% by weight of total developing solution, and wherein said developing solution comprises a non-ionic surfactant and at least another surfactant selected from the group consisting of anionic surfactants and amphoteric surfactants.
Dependencies are inferred from the claim text.