Abstract: A radiation-sensitive composition includes a free radically polymerizable component, an initiator composition capable of generating free radicals sufficient to initiate polymerization upon exposure to imaging radiation, an infrared radiation absorbing dye having a tetraaryl pentadiene chromophore, a polymeric binder comprising a polymer backbone to which are directly or indirectly linked poly(alkylene glycol) side chains, and a nonionic phosphate acrylate having a molecular weight of at least 250. This composition can be used to prepare a negative-working imageable element that is sensitive to suitable imaging radiation and can be imaged at relatively low energy and developed either on-press or off-press.

Abstract: A laser imageable flexographic printing plate precursor comprises a thermoset elastomeric upper layer that is at least partially ablatable and comprises a radiation sensitive compound, and a non-ablatable elastomeric underlayer. This flexographic printing plate precursor can be imaged to provide a printing plate that is primarily useful for “high quality” printing because the resulting relief image is generally not greater than 600 ?m and has an extremely even “floor”. The imaged flexographic printing plate also can have a high visual contrast between the imaged areas and the non-imaged background areas.

Abstract: Sulfated polymers, imageable elements containing these polymers, and methods for preparing images useful as lithographic printing plates from these imageable elements are disclosed. The sulfate groups are attached either to aryl groups that are pendent to the polymer backbone, and/or to alkyl groups that are either pendant to the polymer backbone and/or part of the polymer backbone. The elements can be thermally imaged and developed in water or in fountain solution so that an alkaline developer is not required. They can be imaged and developed on press using fountain solution so that it is unnecessary to mount them in a separate exposure device.

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: Positive-working imageable elements comprise a radiation absorbing compound and inner and outer layers on a substrate having a hydrophilic surface. The inner layer comprises a polymeric material that is removable using an alkaline developer and comprises a backbone and attached groups represented by the following Structure Q: wherein L1, L2, and L3 independently represent linking groups, T1, T2, and T3 independently represent terminal groups, and a, b, and c are independently 0 or 1. The imageable elements have improved resistance to development and printing chemicals and solvents.

Abstract: A radiation-sensitive composition and negative-working imageable element includes a polymeric binder comprising pendant allyl ester groups to provide solvent resistance, excellent digital speed (sensitivity) and can be imaged and developed without a preheat step to provide lithographic printing plates. The polymeric binder can be prepared with a precursor polymer having pendant carboxy groups that are converted to allyl ester groups using an allyl-containing halide in the presence of a base in order to avoid gelation.

Abstract: Negative-working imageable elements can be imaged and then developed using a lower pH organic-based single-phase developer that is less toxic and corrosive and that can be more readily disposed of after use. This developer has a pH less than 12 and comprises a) an amphoteric surfactant comprising a nitrogen-containing heterocycle, b) an amphoteric surfactant having two or more nitrogen atoms, or c) an amphoteric surfactant of a) and an amphoteric surfactant of b).

Abstract: A radiation-sensitive medium comprises hydrophilic polymer particles, the particles comprising a thermally softenable hydrophobic polymer, a hydrophilic polymer and a bonding compound capable of chemically bonding to the hydrophobic polymer and to the hydrophilic polymer. Th radiation-sensitive medium further may comprise a substance capable of converting radiation into heat. The radiation-sensitive medium is aqueous-ineluable when coated and dried, and becomes hydrophobic under the action of heat. The polymer particles are made by polymerization of at least one hydrophobic monomer and at least one bonding compound in the presence of the hydrophilic polymer. The radiation-sensitive medium may be provided as a coatable composition to be applied to substrates to form a processless radiation-imageable lithographic printing precursor.

Abstract: The present invention provides an aqueous regenerator for addition to an aqueous developer that contains an organic solvent, a dispersing agent and a weak base, and has a pH of between about 8 and less than about 13. The aqueous regenerator includes an organic solvent, dispersing agent, and an effective amount of a strong base such that the regenerator has a greater pH than the developer into which the regenerator is to be added.

Abstract: Positive-working imageable elements comprise a radiation absorbing compound and inner and outer layers on a substrate having a hydrophilic surface. The inner layer comprises a combination of two different polymeric binders one of which has an acid number of at least 30, which combination of polymers provides improved post-development bakeability (more quickly baked or cured at lower temperatures) and desired digital speed with no loss in chemical resistance.

Abstract: There are provided a negative-working photosensitive composition which can be cured by infrared rays and is less likely to suffer polymerization inhibition by oxygen during radical polymerization, and also exhibits high adhesion with a metal, and a negative-working photosensitive lithographic printing plate which is capable of directly forming images by irradiation with infrared rays from a solid or semiconductor laser based on digital signals, and also has high sensitivity and excellent printing durability. The negative-working photosensitive composition contains an infrared absorber (A), an organoboron compound (B) which functions as a polymerization initiator by using in combination with the infrared absorber (A), a compound having a polymerizable unsaturated group (C) and a diazo resin (D), and the negative-working photosensitive lithographic printing plate comprises a support, and a photosensitive layer containing the negative-working photosensitive composition formed on the support.

Abstract: A single manufacturing pass for manufacturing a multilayered self-organized coating onto a substrate to provide all of the functions usually provided in multiple-pass coatings for manufacturing an infrared imageable offset lithographic printing plate; and a process whereby two or more polymeric materials that cannot usually co-exist in solution may be dissolved in suitably dilute solvent mixtures which, when coated onto a substrate and the solvents evaporated, deposit a continuous graduation of polymeric mixtures vertical to the substrate, caused by the self-assembly process.

Abstract: Thermally imageable multilayer imageable elements useful as lithographic printing plate precursors that have good solvent resistance are disclosed. The underlayer of the imageable element comprises an acidic copolymer that comprises, in polymerized form, about 10 mol % to about 75 mol % of one or more monomers of the formula: CH2?CH(R1)-Z-X—NH—CO—NH—C6H3—(R2)(CO2H); in which: R1 is H or CH3; R2 is H or OH; Z is —C6H4— or —C(O) —Y—; Y is —O— or —NH—; and X is selected from —C(CH3)2—, —CH(CH3)— and —(CH2)n—, in which n is an integer from 1 to 12.

Abstract: Radiation-sensitive element comprising (a) a substrate with at least one hydrophilic surface and (b) a radiation-sensitive coating on at least one hydrophilic surface of the substrate, wherein the coating comprises: (i) at least one free-radical polymerizable monomer and/or oligomer and/or polymer with at least one ethylenically unsaturated group each, (ii) at least one absorber selected from photoinitiators and sensitizers, which is capable of absorbing radiation of a wavelength in the range of 250 to 1,200 nm and (iii) at least one stabilizer comprising in its molecule at least one group capable of inhibiting free-radical polymerization, and at least one other group capable of sorption at the hydrophilic surface of the substrate.

Abstract: A radiation-sensitive composition includes a radically polymerizable component and a borate initiator composition capable of generating radicals sufficient to initiate polymerization of the radically polymerizable component upon exposure to imaging radiation. This composition also includes a radiation absorbing compound (such as an IR-sensitive dye), a polymeric binder comprising a polymer backbone to which is directly or indirectly linked a pendant group comprising a reactive vinyl group, and a primary additive that is a poly(alkylene glycol) or an ether or ester thereof that has a number average molecular weight of from about 200 and up to 4000 and comprises from about 2 to about 50 weight % based on the total composition solids content. This composition can be used to prepare a negative-working imageable element that can be imaged at relatively low energy and developed without a preheat step.

Abstract: A positive-working radiation-sensitive composition for use with a radiation source comprises one or more polymers capable of being eluted in an alkaline aqueous solution and a development-enhancing compound. The invention provides a positive-working photosensitive composition of good sensitivity for use with one or both of ultra-violet radiation and an infrared laser radiation source. The composition is stable in its state before exposure and has an excellent handling property. The sensitivity of a radiation-sensitive coating based on the composition of this invention is increased without compromising the handling characteristics. Radiation-sensitive elements based on the composition of the invention have good development latitude. A positive-working lithographic printing precursor is based on the radiation-sensitive composition coated on a hydrophilic surface.

Abstract: The invention is directed to methods of making an article bearing a relief image using a removable film. First, an imageable film that contains at least a mask substrate and an imageable material is imagewise exposed to imaging radiation to form an imaged film. The imaged film is then transferred to an imageable article, such as a flexographic printing plate precursor. The resulting assembly is exposed to curing radiation resulting in exposed and unexposed areas of photosensitive material on the imageable article. Following exposure to curing radiation, the imaged film is then removed from the imageable article. The imageable article is then developed with a suitable developer to form a relief image. The imaged film may then be reused to make additional articles bearing the relief image.

Abstract: A method for eliminating unwanted ink-receptive sections in positive working printing plates resulting from shading of the surface layer during exposure by the clamps holding the plate on the exposure apparatus following development of an imagewise exposed precursor. Accordingly the areas that are shaded are identified prior to development and the surface layer is scored in those areas to a depth and density sufficient to result in the scored layer being removed during development but not deep enough to damage the underlying hydrophilic layer.

Abstract: Heat-sensitive element comprising a) an optionally pretreated substrate; b) a positive working coating comprising (i) at least 40 wt.-%, based on the dry weight of the coating, of at least one polymer soluble in aqueous alkaline developer selected from novolak resins, functionalized novolak resins, polyvinylphenol resins, polyvinyl cresols and poly(meth)acrylates with phenolic and/or sulfonamide side groups, (ii) 01-20 wt.-%, based on the dry weight of the coating, of at least one (C4-C20 alkyl)phenol novolak resin insoluble in aqueous alkaline developer, and (iii) optionally at least one further component selected from polymer particles, surfactants, contrast dyes and pigments, inorganic fillers, antioxidants, print-out dyes, carboxylic acid derivatives of cellulose polymers, plasticizers and substances capable of absorbing radiation of a wavelength from the range of 650 to 1,300 nm and converting it into heat.

Abstract: The present invention provides an imageable element including a lithographic substrate and an imageable layer disposed on the substrate. The imageable layer includes a radically polymerizable component, an initiator system capable of generating radicals sufficient to initiate a polymerization reaction upon exposure to imaging radiation, and a polymeric binder having a hydrophobic backbone and including both constitutional units having a pendant cyano group attached directly to the hydrophobic backbone, and constitutional units having a pendant group including a hydrophilic poly(alkylene oxide) segment. When the imageable element is imaged and developed, the resulting printing plate may exhibit improved on-press solvent resistance and longer press life.