Abstract: The present invention provides a radiation sensitive composition suitable for us in on-press developable printing plates. The radiation sensitive composition comprises an initiator system including an onium salt and a radiation absorber. The initiator system is combined with a polymerizable material, and a polymeric binder including polyethylene oxide segments.

Abstract: Processes for imaging and developing imageable elements useful as lithographic printing plate precursors either thermally or with ultraviolet radiation that use the same developer are disclosed. The imageable elements comprise a top layer and an underlayer. The top layer contains a phenolic polymer and a material that has either the o-benzoquinonediazide functionality or the o-diazonaphthoquinone functionality. The developer is a 20:80 to 80:20 mixture of (1) an aqueous alkaline developer that has a pH greater than 11 and contains about 2 wt % to about 8 wt % of an alkali metal silicate, and (2) a solvent based developer that contains about 0.5 wt % to about 15 wt % of an organic solvent or mixture of organic solvents.

Abstract: Infrared absorbing compounds in which the anion is selected from the group consisting of 5-isatinsulfonate, 10-camphorsulfonate, and 4,5-dihydroxy-1,3-benzenedisulfonate are disclosed. Negative-working imageable elements containing these compounds have improved dot stability.

Abstract: A method for forming images useful as lithographic printing plate precursors is disclosed. An imageable element in which the imageable layer comprises an acid generator, a crosslinking agent, and a binder is imaged with ultraviolet radiation and developed with a solvent based developer. The acid generator is an iodonium, sulfonium, or diazonium salt in which the anion is an organic sulfate or thiosulfate anion. The binder comprises a copolymer that contains a reactive pendent group capable of undergoing acid crosslinking, in which the reactive pendent group is hydroxyl, carboxylic acid, sulfonamide, alkoxymethyl, or a mixture thereof. The method is especially suited for use with direct digital ultraviolet imaging devices. The resulting image is useful as a lithographic printing plate.

Abstract: An acid generating agent useful for imaging photosensitive elements selected from compounds of formulae (I), (II) and (III). wherein R1 is selected from the group consisting of an unsubstituted and substituted hydrocarbon or aryl group; wherein X is selected from the group consisting of oxygen, sulfur and selenium; wherein Y is selected from the group consisting of sulfur, selenium and tellurium; wherein Ar1 is selected from the group consisting of an unsubstituted and substituted aryl group; wherein R2, R3 and R4 are individually selected from the group consisting of an unsubstituted and substituted hydrocarbon or aryl group or any two of them are bonded together to form a ring structure; and wherein R5 and R6 are individually selected from the group of an unsubstituted and substituted hydrocarbon or aryl group, or are bonded to each other to form a ring structure.

Abstract: A method for making a relief printing plate from an imageable lithographic printing plate precursor. The relief printing plate has ink-receptive cured areas, and ink-repellent non-image areas. The method comprises the steps of: a) imaging the lithographic printing plate precursor to produce ink-receptive image areas and ink-repellent non-image areas; b) applying a curable composition to form a coating on ink-receptive image areas; and c) curing the coating to produce ink-receptive cured areas. The method of another embodiment further comprises the steps of: d) applying a curable composition to form a coating on ink-receptive cured areas; e) curing the coating on the cured areas; and f) repeating steps d) and e) to attain a desired relief depth for the ink-receptive cured areas. In the practice of an embodiment of the invention, a modified rotary printing press may be employed to make a relief printing plate from a lithographic printing plate.

Abstract: A method for making a relief printing plate, by using a lithographic printing plate to create ink-receptive areas on a receiver base. The relief printing plate has ink-receptive cured areas defining an image. The method comprises the steps of: a) imaging a lithographic printing plate precursor to produce a lithographic printing plate having ink-receptive image areas and ink-repellent non-image areas; b) applying a first curable composition to the lithographic printing plate, to form a coating of the first curable composition on ink-receptive image areas; c) contacting the coating to the receiver base to make an impression on the receiver base; and d) curing the impression on the receiver base to produce ink-receptive cured areas defining an image. In the practice of an embodiment of the invention, a modified rotary printing press may be employed to make a relief printing plate on a receiver base using a lithographic printing plate.

Abstract: Imageable elements that contain silicate-coated polymer particles in the imageable layer, stacks of these elements, and methods for forming images using these elements are disclosed. The elements do not stick to each other when stacked without interleaving paper, and only one imageable element is lifted at a time when the imageable elements are handled by automatic processing equipment. Blanket piling is not observed when silicate-coated particles are present in the imageable layer.

Abstract: Processes for imaging and developing imageable elements useful as lithographic printing plate precursors either thermally or with ultraviolet radiation that use the same developer are disclosed. The imageable elements comprise a top layer and an underlayer. The top layer contains a phenolic polymer and a material that has either the o-benzoquinonediazide functionality or the o-diazonaphthoquinone functionality. The developer is a 20:80 to 80:20 mixture of (1) an aqueous alkaline developer that has a pH greater than 11 and contains about 2 wt % to about 8 wt % of an alkali metal silicate, and (2) a solvent based developer that contains about 0.5 wt % to about 15 wt % of an organic solvent or mixture of organic solvents.

Abstract: A direct-to-press imaging method comprises:

Abstract: A method for forming a printing plate from a printing plate precursor having a radiation-sensitive layer, sensitive to radiation in a first frequency spectrum such as the far or near infrared, and to radiation in a second frequency spectrum other than the first frequency spectrum such as visible or ultraviolet. The plate is exposed twice. Once to imaging radiation in the first frequency spectrum and again to radiation in the second frequency spectrum. The second frequency spectrum exposure is done only to the areas of the plate undesirably shaded during the imagewise exposure.

Abstract: An IR-sensitive composition comprising, in addition to a polymeric binder, a free radical polymerizable system consisting of at least one member selected from unsaturated free radical polymerizable monomers, oligomers which are free radical polymerizable, and polymers containing C═C bonds in the back bone and/or in the side chain groups and an initiator system, wherein the initiator system comprises the following components: (a) at least one material capable of absorbing IR radiation, (b) at least one compound capable of producing radicals and (c) at least one hereto-substituted arylacetic acid co-initiator compound indicated by the following general structures: 1

Abstract: QHB-Modified free radical polymerizable compounds and free radical polymerizable compositions that comprise these compounds are disclosed. A QBH-modified free radical polymerizable compound has at least one moiety that comprises at least one free radical polymerizable group; a supporting backbone, and at least one and preferably at least two moieties capable of forming four or more, typically four, hydrogen bonds with similar or complementary units on other molecules or portions of molecules. Free radical polymerizable compositions that contain these compounds may be used in any of the well-known applications for free radical polymerizable compositions. They are especially useful for the formation of imageable elements useful as lithographic printing plate precursors.

Abstract: Thermally imageable elements and methods for their preparation and use are disclosed. The elements contain, in order, a substrate; an underlayer; and an ink-repellent layer. The underlayer contains a crosslinked allyl functional polyurethane. A photothermal conversion material is present in either in the underlayer or in an absorber layer between the underlayer and the ink-repellent layer. Thermal imaging and development removes the ink-repellent layer and reveals the underlayer in the exposed regions to form an imaged element useful as a waterless lithographic printing plate.

Abstract: The present invention provides an initiator system including an infrared-absorbing compound that exhibits an electronic transition band in the near-infrared region, an initiator, and a metallocene compound. Upon exposure to infrared radiation, the initiator system is capable of producing radicals sufficient to initiate a photopolymerization reaction. Suitable infrared-absorbing compounds include indocyanine dyes, for example. Trihalomethyl triazine compounds and onium compounds are suitable initiators. Suitable metallocene compounds include ferrocenes and titanocenes. The present invention also provides an infrared-sensitive composition including an ethylenically unsaturated polymerizable component, an infrared-absorbing compound that exhibits an electronic transition band in the near-infrared region, an initiator, and a metallocene compound. The infrared-sensitive composition provides improved photospeed and sensitivity in some embodiments.

Abstract: The present invention provides an imageable element, which includes: a substrate; a crosslinked layer disposed on the substrate; and an imageable ink-receptive layer disposed on the crosslinked layer, the imageable ink-receptive layer including an ablation free imageable composition. The present invention provides methods of producing the above imaged element.

Abstract: Thermally imageable elements and methods for their preparation and use are disclosed. The elements contain, in order, a substrate; an underlayer; and an ink-repellent layer. The underlayer contains a crosslinked allyl functional polyurethane. A photothermal conversion material is present in either in the underlayer or in an absorber layer between the underlayer and the ink-repellent layer. Thermal imaging and development removes the ink-repellent layer and reveals the underlayer in the exposed regions to form an imaged element useful as a waterless lithographic printing plate.

Abstract: An acid generating agent useful for imaging photosensitive elements selected from compounds of formulae (I), (II) and (III).

Abstract: A positive working, multi-layer thermally imageable element is disclosed. The element comprises a substrate, an underlayer, and a top layer. The top layer comprises a crosslinked polymeric material. The element may be thermally imaged and developed to form a lithographic printing plate.

Abstract: A direct-to-press imaging method comprises: (a) applying an imageable coating to a printing cylinder, wherein the imageable coating comprises a composition such as a thermally switchable polymer which changes affinity for a printing fluid upon exposure to imaging radiation such as infrared radiation delivered imagewise via a laser, and the imageable coating is substantially insoluble in the printing fluid; (b) imagewise exposing the imageable coating to actinic radiation to obtain an imaged coating; (c) printing a plurality of copies of an image from the imaged coating; and (d) reapplying the imageable coating as desired by repeating steps (a) through (c) at least once without substantially removing the prior imaged coating before reapplying the imageable coating.