On-press developable negative-working imageable elements

Abstract

The present invention relates to negative-working imageable elements that can be used for the manufacture of printing plates. These imageable elements can be developed on on-press by the action of a lithographic printing ink used in combination with either water or a fountain solution. The imageable elements comprise an imageable layer that is not removable in water or fountain solution alone. The imageable layer includes a free radically polymerizable compound, a free radical initiator composition, an infrared radiation absorbing compound, and a polymeric binder comprising poly(alkylene oxide) pendant groups, and preferably additionally pendant cyano groups.

1 . An on-press developable, negative-working imageable element comprising an infrared radiation imageable layer on a substrate, said imageable layer comprising:
 a free radically polymerizable component,   a free radical initiator composition,   an infrared radiation absorbing compound, and   a polymer binder,   said imageable layer being completely removable prior to irradiation only when contacted, sequentially or simultaneously, with either water or a fountain solution and a lithographic printing ink, said imageable layer further comprising a nonionic phosphate acrylate having a molecular weight of at least 250 and 2 or more ethylene oxide units.