Abstract: A lithographic printing plate precursor has a substrate and an infrared radiation-sensitive composition comprising a polymeric binder, a free radical polymerizable system consisting of at least one polymerizable component, a compound capable of absorbing infrared radiation, and an initiator system comprising an iodonium salt that is capable of producing free radicals; and at least 1% and up to and including 10% by weight, based on the infrared-sensitive composition, of at least one mono- or polycarboxylic acid having an aromatic moiety.

Abstract: The present invention provides an infrared-sensitive composition including an initiator system comprising: (a) an infrared absorbing compound; (b) a radical producing compound; and (c) a carboxylic acid co-initiator compound. In some embodiments of the invention, the co-initiator is a monocarboxylic acid. In other embodiments of the present invention, the co-initiator is a polycarboxylic acid. The infrared-sensitive composition further includes a polymeric binder and 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. In some embodiments of the present invention, the acid number of the polymeric binder is 70 mg KOH/g or less. The present invention further provides a printing plate precursor, a process for preparing the printing plate and a method of producing an image.

Abstract: Improved photopolymerization initiator systems are comprised of a spectral sensitizer that sensitizes in the ultraviolet or visible regions of the spectrum and an N-aryl, O-aryl or S-aryl polycarboxylic acid co-initiator. The improved initiator systems are incorporated in photo-polymerizable compositions containing one or more addition-polymerizable ethylenically-unsaturated compounds to form compositions suitable for the preparation of radiation-sensitive layers in lithographic printing plates adapted to be imagewise-exposed with ultraviolet- or visible-light-emitting lasers such as argon-ion lasers and frequency doubled Nd:YAG lasers. Such plates are able to effectively meet the dual requirements of very high photospeed and very good shelf-life required in computer-to-plate systems.

Abstract: Improved photopolymerization initiator systems are comprised of a spectral sensitizer that sensitizes in the ultraviolet or visible regions of the spectrum and an N-aryl, O-aryl or S-aryl polycarboxylic acid co-initiator. The improved initiator systems are incorporated in photo-polymerizable compositions containing one or more addition-polymerizable ethylenically-unsaturated compounds to form compositions suitable for the preparation of radiation-sensitive layers in lithographic printing plates adapted to be imagewise-exposed with ultraviolet- or visible-light-emitting lasers such as argon-ion lasers and frequency doubled Nd:YAG lasers. Such plates are able to effectively meet the dual requirements of very high photospeed and very good shelf-life required in computer-to-plate systems.

Abstract: Improved lithographic printing plates adapted to be imagewise-exposed with ultraviolet- or visible-light-emitting lasers such as argon-ion lasers and frequency doubled Nd:YAG lasers, are comprised of a radiation-sensitive layer and an oxygen barrier layer. The radiation-sensitive layer includes one or more addition-polymerizable ethylenically-unsaturated compounds and a photopolymerization initiator system comprised of a spectral sensitizer that sensitizes in the ultraviolet or visible regions of the spectrum and an N-aryl, O-aryl or S-aryl polycarboxylic acid co-initiator; the oxygen barrier layer comprises fully hydrolyzed polyvinyl alcohol; and a basic compound is incorporated in the oxygen barrier layer or the radiation-sensitive layer or both in an amount sufficient to control thermal fog susceptibility of the lithographic printing plate.

Abstract: Improved lithographic printing plates adapted to be imagewise-exposed with ultraviolet- or visible-light-emitting lasers such as argon-ion lasers and frequency doubled Nd:YAG lasers, are comprised of a radiation-sensitive layer and an oxygen barrier layer. The radiation-sensitive layer includes one or more addition-polymerizable ethylenically-unsaturated compounds and a photopolymerization initiator system comprised of a spectral sensitizer that sensitizes in the ultraviolet or visible regions of the spectrum and an N-aryl, O-aryl or S-aryl polycarboxylic acid co-initiator; the oxygen barrier layer comprises fully hydrolyzed polyvinyl alcohol; and a basic compound is incorporated in the oxygen barrier layer or the radiation-sensitive layer or both in an amount sufficient to control thermal fog susceptibility of the lithographic printing plate.

Abstract: A peel-developable lithographic printing plate is comprised of a substrate, a hydrophilic layer comprising a polymeric acid overlying the substrate, a radiation-sensitive image-forming layer overlying the hydrophilic layer and a stripping layer that is strippably adhered to the image-forming layer. The image-forming layer is comprised of a photo-polymerizable composition comprising a polymeric binder, a plurality of addition-polymerizable ethylenically-unsaturated compounds at least one of which possesses phosphorus-derived acidic functionality and a photopolymerization initiator. After imagewise exposure of the plate to activating radiation, the stripping layer is peeled from the image-forming layer with only the unexposed regions of the image-forming layer adhering thereto so as to reveal the underlying hydrophilic layer and thereby form a lithographic printing surface.

Abstract: A masking element is prepared with a photosensitive layer on a suitable support, overcoated with a masking layer containing an infrared absorbing compound and a thermally bleachable dye. The dye is bleached by imagewise laser irradiation, followed by floodwise exposure to produce an image in the photosensitive layer corresponding to the laser produced image. The outermost layers are removed and development provides a suitable negative-working printing plate.

Abstract: An infrared imaging composition comprises three essential components: a photocrosslinkable polymeric binder having pendant photopolymerizable olefinic double bonds, a polyazide photoinitiator and an infrared absorbing compound. These compositions are useful in photosensitive elements such as lithographic printing plates that can be used to provide images using lasers, followed by development.

Abstract: An infrared imaging composition contains two essential components, namely an infrared absorbing compound, and a phenolic resin that is either mixed or reacted with an o-diazonaphthoquinone derivative. These compositions are useful in photosensitive elements such as lithographic printing plates that can be adapted to direct-to-plate imaging procedures.

Abstract: An infrared imaging composition contains two essential components, namely an infrared radiation absorbing compound, and a phenolic resin that is either mixed or reacted with an o-diazonaphthoquinone derivative. These compositions are useful in photosensitive elements such as lithographic printing plates that can be used to provide images using laser imaging, followed by uniform exposure and development.