Abstract: A film-forming oleophilic photopolymerizable composition is formed from a fluid epoxy resin having an epoxy equivalent of less than 350 and a photosensitive condensation product of a paradiazodiphenylamine fluoroborate and an organic condensation agent. The photopolymerizable compositions can be used as the photosensitive layer of negative lithographic plates, such as printing plates.Acidic aqueous solvent-developable negative lithographic plates are also provided in which the photosensitive layer is formed from a layer of the film-forming oleophilic photopolymerizable composition which is deposited on a hydrophilic support from an organic solvent solution.The lithographic printing plates of the present invention have high mechanical resistance, long shelf-life and can be used in large production runs to make a great number of copies.

Abstract: A film-forming oleophilic photopolymerizable composition is formed from a fluid epoxy resin having an epoxy equivalent of less than 350 and a photosensitive reaction product of a water-soluble, photosensitive condensation product of a diazonium compound and an organic condensation agent with an organic coupling agent. The organic coupling agent is selected such that the photosensitive reaction product is soluble in organic solvents but only slightly soluble in water. The photopolymerizable compositions can be used as the photosensitive layer of water-developable negative lithographic plates, such as printing plates.Water-developable negative lighographic plates are also provided in which the photosensitive layer is formed from a layer of the film-forming oleophilic photopolymerizable composition which is deposited on a hydrophilic support from an organic solvent solution.

Abstract: Montage films, duplicating films, color guide films, microfiche film, color transparencies and similar visual aids are prepared from photosensitive articles having a layer of a photosensitive composition coated on a transparent support, preferably a flexible plastic transparent support.The exposed articles are developable with water to form the visual aid. The photosensitive layer is formed from a composition which includes a photosensitive reaction product of a condensation product of a diazonium compound with an arylsulfonic acid, and an epoxy resin which is liquid at ambient temperatures. The diazonium compound is preferably a paradiazodiphenylamine and the preferred condensing agent is formaldehyde or paraformaldehyde.The photosensitive layer can be colored with a permanent dye of a color depending on the type and use of the visual aid.

Abstract: A method of making a presensitized lithographic plate is disclosed wherein a steel support having a tin-plated layer is depassivated and coated with a photosensitive product. Depassivation is accomplished by immersion of the support in an electrolytic bath of sodium carbonate. The electrolysis is performed with the support as a cathode and reversed so that the support is an anode of the bath. Preferably, the bath is an aqueous solution of 50 grams per liter of sodium carbonate at a temperature of 65.degree. C. with a current density of the bath being approximately 2.5 amperes per dm.sup.2. It is also contemplated that the depassivated tin-plated layer may be coated with copper before application of the photosensitive product. This can be accomplished by immersion in an electrolytic bath of copper cyanide. Preferably, the copper cyanide bath is at a temperature of 65.degree. C. with immersion occurring for approximately 3 minutes with the support in the cathode position and having a current density of 2.

Abstract: The adherence of the oleophilic polymer printing surface of a lithographic printing plate to the support of the lithographic printing plate is improved by an anchoring layer formed from a hydrophobic oleophilic ester colloid which is capable of being rendered hydrophilic by treatment with an aqueous alkali solution. After an image-wise exposure of the photosensitive layer of the presensitized photosensitive sheet used to prepare the lithographic printing plate and removal of the non-polymerized (non-image) portions of the photosensitive layer the plate is contacted with an aqueous alkali solution to render those portions of the anchoring layer, which have been exposed by removal of the non-polymerized portions of the photosensitive layer, hydrophilic. Accordingly, the portions of the anchoring layer underlying the oleophilic hardened polymeric printing surface remain hydrophobic oleophilic and therefore can increase the number of satisfactory printings which can be made from the lithographic printing plate.