Abstract: Radiation-sensitive elements are described whose radiation-sensitive coating comprises both a photopolymerizable oligomer with a biuret structural unit and a photopolymerizable phosphazene oligomer.

Abstract: The invention relates to radiation-sensitive elements comprising an aluminum substrate that has been roughened electrochemically with hydrochloric acid, and a radiation-sensitive coating comprising a coumarin sensitizer (I), a coinitiator a free-radical polymerizable monomer one or more P—OH groups and a biuret oligomer.

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 process for the production of lithographic printing plate precursors with a coating comprising a diazo resin is described, wherein a solvent mixture comprising (i) 2 to 9.9 wt.-% 1-methoxy-2-propanol, (ii) 20 to 50 wt.-% of at least one ketone with a boiling point below 130° C., (iii) 20 to 60 wt.-% of at least one alkanol with a boiling point below 120° C., and (iv) 10 to 30 wt.-% ethyl lactate, and a slot coater are used to produce the printing plate precursors.

Abstract: Apparatus and method for exposing a lithographic printing plate wherein the apparatus includes a plurality of laser diodes emitting light of wavelength between 350 nm and 450 nm. The light from each of the laser diodes is directed onto the lithographic printing plate such that each spot on the lithographic printing plate receives light emitted from at least one of the laser diodes. Preferably, the lithographic printing plate is a violet-sensitive lithographic member and the lithographic member is a printing press plate. The power of each laser diode may be between 5 mW and 30 mW, and preferably the laser diodes emit light of wavelength between 390 nm and 430 nm.

Abstract: The present invention includes an imageable element, which can be: (a) an imageable element comprising an imaging layer which comprises: an aromatic diazonium salt containing compound having an alkoxy substituent and an aromatic diazonium salt containing compound free of an alkoxy substituent; a polyvinyl acetal binder; and a sheet substrate; or (b) an imageable element comprising an imaging layer which comprises: an aromatic diazonium salt containing compound having an alkoxy substituent and an aromatic diazonium salt containing compound free of an alkoxy substituent; and a sheet substrate. The imaging layer includes a total aromatic diazonium salt containing compound content of at least 10 weight percent. The molar ratio of the aromatic diazonium salt containing compound having an alkoxy substituent to the aromatic diazonium salt containing compound that is free of an alkoxy substituent is from about 1.0:1 to 70:1. Upon imagewise exposure and development, an imaged element is obtained.

Abstract: The present invention relates to a light-sensitive composition containing: (i) at least one diazonium polycondensation product or at least one system that can be radically polymerized and consists of photoinitiators and unsaturated compounds which can be radically polymerized or at least one hybrid system consisting of a diazonium polycondensation product and a system that can be radically polymerized and consists of photo initiators and unsaturated compounds which can be radically polymerized, (ii) at least one binding agent and optionally one or more exposure indicators, one or more dyes for increasing the image contrast and one or more acids for stabilizing the light-sensitive composition which is characterized in that the binding agent essentially consists of units (A, B, C, D), whereby A corresponds to formula (I), B corresponds to formula (II), C corresponds to formula (III) and D corresponds to formula (IV). The invention also relates to the use thereof for coating printing plates.

Abstract: Polymeric acetal resins useful in lithographic printing are disclosed. The polymeric acetal resin contains units (A), (B), (C), (D), and (E). Unit (A) is a vinyl alcohol unit. Unit; (B) is a polyvinyl acetal unit containing an R group, where R is hydrogen, an aliphatic group, an aromatic group, or an arylaliphatic group. Unit (C) is a vinyl carboxylate unit. Unit (D) is an acidic vinyl acetal unit and/or a residue of an acidic vinyl monomer. Unit (E) is a free radical polymerization-inhibiting vinyl acetal unit and/or a free radical polymerization-inhibiting vinyl alcohol ester unit. The resin comprises about 10 to about 60 mol % of unit (A), about 5 to about 60 mol % of unit (B), about 0.3 to about 30 mol % of unit (C), about 1 to about 40 mol % of unit (D), and about 0.01 to about 2 mol % of unit (E).

Abstract: The present invention includes an imageable element, which can be: (a) an imageable element comprising an imaging layer which comprises: an aromatic diazonium salt containing compound having an alkoxy substituent and an aromatic diazonium salt containing compound free of an alkoxy substituent; a polyvinyl acetal binder; and a sheet substrate; or (b) an imageable element comprising an imaging layer which comprises: an aromatic diazonium salt containing compound having an alkoxy substituent and an aromatic diazonium salt containing compound free of an alkoxy substituent; and a sheet substrate. The imaging layer includes a total aromatic diazonium salt containing compound content of at least 10 weight percent. The molar ratio of the aromatic diazonium salt containing compound having an alkoxy substituent to the aromatic diazonium salt containing compound that is free of an alkoxy substituent is from about 1.0:1 to 70:1. Upon imagewise exposure and development, an imaged element is obtained.

Abstract: A visible radiation sensitive composition is disclosed. The composition comprises at least one ethylenically unsaturated monomer capable of free radical initiated addition polymerization; optionally, at least one binder; and a photoinitiator system comprising a coinitiator and a cyanopyridone sensitizer. The coinitiator preferably comprises a metallocene and an onium compound.

Abstract: A lithographic printing plate precursor comprises a substrate, a free radical polymerizable photosensitive layer comprising a light-sensitive composition on the substrate, and a water-soluble overcoat layer on the photosensitive layer, wherein the overcoat layer comprises polyvinyl alcohol, and a further component that is not amphoteric and is poly(1-vinylimidazole) or a copolymer of 1-vinylimidazole and at least one further monomer. The photosensitive layer comprises a free radical polymerizable component and a photoinitiator.

Abstract: The present invention includes an imageable element, which can be: (a) an imageable element comprising an imaging layer which comprises: an aromatic diazonium salt containing compound having an alkoxy substituent and an aromatic diazonium salt containing compound free of an alkoxy substituent; a polyvinyl acetal binder; and a sheet substrate; or (b) an imageable element comprising an imaging layer which comprises: an aromatic diazonium salt containing compound having an alkoxy substituent and an aromatic diazonium salt containing compound free of an alkoxy substituent; and a sheet substrate. The imaging layer includes a total aromatic diazonium salt containing compound content of at least 10 weight percent. The molar ratio of the aromatic diazonium salt containing compound having an alkoxy substituent to the aromatic diazonium salt containing compound that is free of an alkoxy substituent is from about 1.0:1 to 70:1.

Abstract: Polymeric acetal resins useful in lithographic printing are disclosed. The polymeric acetal resin contains units (A), (B), (C), (D), and (E). Unit (A) is a vinyl alcohol unit. Unit; (B) is a polyvinyl acetal unit containing an R group, where R is hydrogen, an aliphatic group, an aromatic group, or an arylaliphatic group. Unit (C) is a vinyl carboxylate unit. Unit (D) is an acidic vinyl acetal unit and/or a residue of an acidic vinyl monomer. Unit (E) is a free radical polymerization-inhibiting vinyl acetal unit and/or a free radical polymerization-inhibiting vinyl alcohol ester unit. The resin comprises about 10 to about 60 mol % of unit (A), about 5 to about 60 mol % of unit (B), about 0.3 to about 30 mol % of unit (C), about 1 to about 40 mol % of unit (D), and about 0.01 to about 2 mol % of unit (E).

Abstract: A visible radiation sensitive composition is disclosed. The composition comprises at least one ethylenically unsaturated monomer capable of free radical initiated addition polymerization; optionally, at least one binder; and a photoinitiator system comprising a coinitiator and a cyanopyridone sensitizer. The coinitiator preferably comprises a metallocene and an onium compound.

Abstract: The present invention relates to a light-sensitive composition containing: (i) at least one diazonium polycondensation product or at least one system that can be radically polymerized and consists of photoinitiators and unsaturated compounds which can be radically polymerized or at least one hybrid system consisting of a diazonium polycondensation product and a system that can be radically polymerized and consists of photo initiators and unsaturated compounds which can be radically polymerized, (ii) at least one binding agent and optionally one or more exposure indicators, one or more dyes for increasing the image contrast and one or more acids for stabilizing the light-sensitive composition which is characterized in that the binding agent essentially consists of units (A, B, C, D), whereby A corresponds to formula (I), B corresponds to formula (II), C corresponds to formula (III) and D corresponds to formula (IV). The invention also relates to the use thereof for coating printing plates.

Abstract: Copolymers containing the units A, B, C, D and optionally E are used to prepare radiation sensitive compositions and lithographic printing plates. The copolymer contains about 25 to 55 mol % of unit A which has the formula The copolymer contains about 0.5 to 25 mol % of unit B which has the formula wherein R1 is selected from the group consisting of alkyl, aryl and aralkyl. The copolymer contains about 0.5 to 40 mol % of unit C which has the formula wherein X is an aliphatic or aromatic spacer group, and Ac is an acidic group selected from the group consisting of —COOH, —SO3H, —SO2NR9R10 with R9 and R10 independently being selected from hydrogen and alkyl; and when X is phenylene, Ac can also be OH.

Abstract: Copolymers containing the units A, B, C, D and optionally E are used to prepare radiation sensitive compositions and lithographic printing plates.

Abstract: The present invention includes an imageable element, which can be: (a) an imageable element comprising an imaging layer which comprises: an aromatic diazonium salt containing compound having an alkoxy substituent and an aromatic diazonium salt containing compound free of an alkoxy substituent; a polyvinyl acetal binder; and a sheet substrate; or (b) an imageable element comprising an imaging layer which comprises: an aromatic diazonium salt containing compound having an alkoxy substituent and an aromatic diazonium salt containing compound free of an alkoxy substituent; and a sheet substrate. The imaging layer includes a total aromatic diazonium salt containing compound content of at least 10 weight percent. The molar ratio of the aromatic diazonium salt containing compound having an alkoxy substituent to the aromatic diazonium salt containing compound that is free of an alkoxy substituent is from about 1.0:1 to 70:1.

Abstract: An aqueous developer for imageable elements that contain a radiation-sensitive initiator system and at least one free radical polymerizable material is disclosed. The developer develops these plates quickly, with high throughput, but with no sludge formation in the developing process. The developer contains water, a buffer, and one or more filter dyes and/or one of more free radical inhibitors. The imageable elements are useful as printing plates.

Abstract: An aqueous developer for imageable elements that contain a radiation-sensitive initiator system and at least one free radical polymerizable material is disclosed. The developer develops these plates quickly, with high throughput, but with no sludge formation in the developing process. The developer contains water, a buffer, and one or more filter dyes and/or one of more free radical inhibitors. The imageable elements are useful as printing plates.