Patent ID: 6558876
Filing Date: 2003-05-06
Classification: G03F,Y10S

Abstract:
A process for making a flexographic photopolymer printing plate comprising, in order:(1) providing a photosensitive element comprising: (a) a support; (b) at least one layer of a photopolymerizable material on the support, the photopolymerizable material comprising at least one elastomeric binder, at least one monomer, at least one initiator having sensitivity to non-infrared actinic radiation, and optionally at least one plasticizer, wherein at least one of the monomer and the optional plasticizer is a low molecular weight material having a weight average molecular weight of 30,000 or less; and (c) at least one infrared ablation layer which is ablatable by infrared radiation and opaque to non-infrared actinic radiation, said infrared ablation layer being in direct contact with the at least one layer of photopolymerizable material (b) and having a surface opposite the photopolymerizable layer (b) capable of being exposed to laser ablation, the infrared ablation layer comprising: (i) at least one infrared absorbing material; (ii) a radiation opaque material, wherein (i) and (ii) can be the same or different; and (iii) at least one binder which is substantially incompatible with at least one of the low molecular weight materials of layer (b), wherein the infrared ablation layer is tack-free or substantially tack-free when on the photopolymerizable layer; and optionally, (d) a coversheet; (2) removing the coversheet when present; (3) imagewise ablating layer (c) with infrared laser radiation to form a mask; (4) overall exposing the photosensitive element to actinic radiation through the mask; and (5) treating the product of step (4) with at least one developer solution to remove (I) the infrared ablation layer which was not removed during step (3), and (II) the areas of the photopolymerizable layer (b) which were not exposed to non-infrared actinic radiation.