Patent ID: 6194125
Filing Date: 2001-02-27
Classification: G03F,Y10S

Abstract:
A process for the production of a photopolymeric letterpress printing plate, wherein said process consists essentially of arranging one on top of the other on a dimensionally stable substrate having a thickness of from 50 to 1100 .mu.m:a layer (A) consisting essentially of a mixture of at least one polymeric binder; said binder being soluble or dispersible in water or a water/alcohol mixture, or in a copolymerizable ethylenically unsaturated organic compound which is compatible with the polymeric binder and a photoinitiator or photoinitiator system; said layer (A) being cross-linkable by actinic radiation;a layer (B) comprising a film-forming polymeric binder; said binder being soluble or dispersible in water or a water/alcohol mixture; said binder comprising at least one substance which is finely distributed in the binder; said layer (B) being sensitive to IR radiation and having a high absorbence to IR radiation in the wavelength range of from 750 to 20,000 nm; said layer (B) having a peelable protective film applied to one of its surfaces; said layer (B) having an optical density .gtoreq.2.5 in the actinic range; and then removing the protective film from layer (B); structuring the layer (B) by laser ablation; exposing the structure layer (B) uniformly to actinic radiation; developing the exposed layer (B) with water or a water/alcohol mixture; and they drying the plate.