Patent ID: 6040116
Filing Date: 2000-03-21
Classification: G03F

Abstract:
A process for the production of a flexographic relief printing plate having a photopolymerized relief layer from a photosensitive recording element comprising (A) a dimensionally stable substrate, (B) a photopolymerizable relief-forming recording layer, which comprises a single layer or two or more individual layers, and (C) an optically transparent top layer,wherein the optically transparent top layer (C) firmly adheres to the surface of the recording layer (B),said process comprising:(1) imagewise exposure of the photopolymerizable relief-forming recording layer (B) to actinic light, with the result that there is a difference between the solubilities of the exposed and unexposed parts of the recording layer (B),(2) washout (development) of the optically transparent top layer (C) and of the unexposed and therefore nonphotopolymerized parts of the imagewise exposed relief-forming recording layer (B) with a developer with formation of the photopolymerized relief layer,whereindevelopment (process step 2) is carried out in one operation using a water-in-oil emulsion as the sole developer,the water-in-oil emulsion consists of an aqueous phase and an organic phase,the organic phase consists of a solvent selected from the group consisting of n-hexane, n-heptane, octane, cyclohexane, hexylcyclohexane, petroleum ether, naphtha, mineral spirits, mineral spirits from which aromatic constituents have been removed, synthetic isoparaffins, n-paraffins, hydrogenated mineral oils, petroleum fractions, hydrogenated oil fractions, xylene, ethylbenzene, diethyl-substituted benzenes, n-butylbenzene, n-pentylbenzene, n-hexylbenzene, isopropylbenzene, ketones, halogenated aliphatic hydrocarbons, a mixture of two or more of these solvents, and a mixture of one or more of these solvents with alcohol and/or minor amounts of surfactant, andthe optically transparent top layer (C) is soluble in aqueous solvents but insoluble in the organic phase suitable and effective for developing the layer (B), and the unexposed parts of the recording layer (B) are insoluble in aqueous solvents.