Patent ID: 7816065

Claim:
An organic composition for photopolymer coating an anodized, hydrophilic substrate to form a radiation imageable lithographic printing plate comprising: a non-aqueous solution of (a) a polymer selected from the group consisting of acrylates, siloxanes, and styrene maleic anhydrides, and one or both of a monomer that is selected form the group consisting of multifunctional acrylates and an oligomer, capable of radically cross-linking with each other when the coating is exposed to imaging radiation, (b) a non-polymerizable organic compound selected from the group consisting of N,N′-diallyltartardiamide (an allyl amide derived from tartaric acid) and tetra methyl tartaramide, and (c) a water-insoluble initiator capable of generating free radicals sufficient to initiate a polymerization reaction upon exposure to imaging radiation; wherein the non-polymerizable organic compound is also partially soluble in water such that after imaging of the dried coating as deposited on an anodized, hydrophilic substrate, only the non-imaged coating areas are removable as dislodged material from the substrate surface by penetration of water through the non-imaged coating areas without dissolution of the as-deposited and the cross linked polymer, monomer, and/or oligomer of the coating, to form a lithographic printing plate with clearly defined image areas of cross linked coating and non-image areas of substrate surface.