Patent ID: 8007984
Filing Date: 2011-08-30
Classification: G03F

Abstract:
1. A process for the production of flexographic printing plates by thermal development, in which the starting material used is a photopolymerizable flexographic printing element which comprises, arranged one on top of the other, at least a dimensionally stable substrate, at least one photopolymerizable relief-forming layer, at least comprising an elastomeric binder, ethylenically unsaturated monomers, plasticizer and photoinitiator, and the thermal development process comprises at least the following steps: (a) imagewise exposure of the photopolymerizable relief-forming layer to actinic radiation to produce polymerized and unpolymerized portions of the relief-forming layer, (b) heating of the relief-forming layer to a temperature of from 40 to 200° C. after imagewise exposure to soften the unpolymerized portions of the relief-forming layer, (c) removal of the softened, unpolymerized portions of the relief-forming layer to form a printing relief, wherein steps (b) and (c) are performed simultaneously or sequentially (b) then (c); and wherein the elastomeric binder is at least one styrene/butadiene block copolymer having a molecular weight M