Abstract:
To provide a lithographic printing plate precursor which is capable of undergoing image recording with infrared laser and exhibits high printing durability while maintaining stain resistance and preservation stability, and particularly, to provide a lithographic printing plate precursor capable of undergoing on-press development and a plate making method thereof, the invention is directed to a lithographic printing plate precursor comprising a hydrophilic support having thereon an image-recording layer containing (A) a polymer fine particle, (B) a radical polymerizable compound and (C) an infrared absorbing dye, wherein (A) the polymer fine particle is obtained by a reaction between a polyvalent isocyanate compound which is an adduct of a polyhydric phenol compound having two or more hydroxyl groups in its molecule and isophorone diisocyanate and a compound having an active hydrogen atom.
Abstract:
A method of making a lithographic printing plate comprising the steps of : a) providing a lithographic printing plate precursor comprising a support having a hydrophilic surface or which is provided with a hydrophilic layer, and a coating provided thereon, said coating comprising (i) a contiguous photopolymerisable layer having a photopolymerisable composition, or (ii) a contiguous intermediate layer and thereon a photopolymerisable layer having a photopolymerisable composition, wherein said photopolymerisable composition comprises a polymerisable compound, a polymerization initiator and a first polymer, b) image-wise exposing said coating, c) optionally, heating the precursor, d) developing the precursor by treating the coating of the precursor with a gum solution or by mounting the exposed precursor on a plate cylinder of a lithographic printing press and rotating the plate cylinder while feeding dampening liquid and/or ink to the coating, wherein said contiguous photopolymerisable or intermediate layer further comprises (1) an adhesion promoting compound which is a non-polymeric compound containing a group having an ethylenically unsaturated bond and a group selected from a phosphate group, a phosphonate group and a trialkoxysilane group, and (2) a second polymer having at least 1 mol % of a first monomeric unit having a phosphate group, a phosphonate group, a carboxylic acid group, a sulphonic acid group, a phenolic group, a trialkoxysilane group, an ammonium group or a phosphonium group and at least 30 mol % of a second monomeric unit having a hydrophilic group, wherein the amount of said adhesion promoting compound is higher than the amount of said second polymer, with the proviso that, if the contiguous layer is the photopolymerisable layer, the amount of said second polymer xn the photopolymerisable layer is at least 0.01 % by weight and less than 5 % by weight.
Abstract:
A heat-sensitive positive-working lithographic printing plate precursor is disclosed which comprises on a support having a hydrophilic surface or which is provided with a hydrophilic layer, a heat and/or light-sensitive coating comprising a surfactant, characterized in that said surfactant comprises a polyether block including a pendant fluoroalkylgroup and a urethane linking group.
Abstract:
Imageable elements that can be imaged using infrared radiation comprise an imageable layer and a protective overcoat on a hydrophilic substrate. The imageable layer includes an IR-sensitive cyanine dye. The protective overcoat predominantly comprises one or more poly (vinyl alcohol) resins, each of which has a hydrolysis level of 85% or less. The use of this particular overcoat composition used in combination with the IR-sensitive cyanine dye provides improved tolerance to fogging by white light while maintaining desired imaging speed. The imageable elements are used for negative-working lithographic printing plates.
Abstract:
A method of making a lithographic printing plate comprising the steps of : a) providing a lithographic printing plate precursor comprising (i) a support having a hydrophilic surface or which is provided with a hydrophilic layer, (ii) a coating on said support, comprising an imaging layer, and, optionally, an intermediate layer between the imaging layer and the support, wherein said imaging layer comprises a switchable polymer, b) image-wise exposing said coating, whereby said polymer undergoes a chemical reaction induced by said exposing, thereby creating a lithographic image consisting of printing areas and non-printing areas wherein the non-printing areas are removable from the support by a gum solution, c) developing the precursor by treating the coating of the precursor with said gum solution, thereby removing the non-printing areas.