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 invention relates to a method for making a lithographic printing plate which comprises imagewise exposing a lithographic printing plate precursor comprising one or more layers at least one of which is associated with one or more unsubstituted or substituted triarylmethane dyes and at least one of which layers is radiation-sensitive, and developing the imagewise exposed printing plate precursor with an aqueous alkaline developing composition, wherein the composition comprises at least one amphoteric surfactant of formula (I):—wherein R1 is an unsubstituted alkyl group; each R2 and each R3 are independently selected from H, hydroxy and an unsubstituted or substituted alkyl group; R4 and R5 are independently selected from an unsubstituted alkyl group or one Of R4 and R5 may be the group —(CH2)m—Y—R1; X? is selected from COO?, SO3?, OSO3?, PO3H?, PO3Z?, OPO3H? and OPO3Z?, wherein Z is a monovalent cation; Y is selected from CONH, NHCO, COO, OCO, NHCONH and O; l is 0 or 1; m is an integer from 1 to 10; and n i

Abstract: Lithographic printing plate precursor comprising: a) an untreated or pretreated substrate and b) a radiation-sensitive coating comprising: (i) at least one polymeric binder soluble or swellable in aqueous alkaline developers; (ii) at least one free-radical polymerizable monomer and/or oligomer comprising at least one non-aromatic C—C double bond and at least one SH group in the molecule; and (iii) a radiation-sensitive initiator or initiator system for free-radical polymerization, wherein component (ii) has the formula (I) wherein each R1a, R1b and R1c is independently selected from H, C1-C6 alkyl, C2-C8 alkenyl, aryl, halogen, CN and COOR1d, wherein R1d is H, C1-C18 alkyl, C2-C8 alkenyl, C2-C8 alkynyl or aryl; and Z is an aliphatic, heterocyclic or heteroaromatic spacer or a combination of two or more thereof, wherein Z can optionally comprise one or more additional SH groups and/or one or more additional non-aromatic C—C double bonds; and each Z1 is independently selected from a single bond, formulae (Ia),

Abstract: Lithographic substrate comprising (a) a dimensionally stable plate- or foil-shaped support, (b) an aluminum oxide layer provided on at least one side of the support (a), and (c) a hydrophilic layer applied onto the aluminum oxide layer comprising at least one phosphono-substituted siloxane of the general formula (I).

Abstract: Lithographic substrate comprising (a) a dimensionally stable plate- or foil-shaped support, (b) an aluminum oxide layer provided on at least one side of the support (a), and (c) a hydrophilic layer applied onto the aluminum oxide layer comprising at least one phosphono-substituted siloxane of the general formula (I)

Abstract: Process for the production of lithographic printing plates comprising (a) providing a lithographic substrate with a hydrophilic surface; (b) applying a negative working radiation-sensitive composition onto the hydrophilic surface, wherein the composition comprises: (i) one or more types of monomers and/or oligomers and/or polymers, each comprising at least one ethylenically unsaturated group accessible to a free-radical polymerization, (ii) at least one sensitizer which in the presence of at least one coinitiator and upon exposure to radiation of a wavelength of 300 to <480 nni or >750 to 1,100 nm initiates the free-radical polymerization of component (i); and (iii) at least one binder with acidic functional groups and is substantially not sensitive to the wavelength range of 480 to 750 nm; (c) image-wise exposure of the resulting negative working lithographic printing plate precursor to radiation selected from the wavelength range of 300 to <480 nm or >750 to 1,100 nm depending on the sensitizer

Abstract: Radiation-sensitive element comprising (a) an optionally pretreated substrate and (b) a radiation-sensitive coating consisting of a composition comprising (i) one or more types of monomers and/or oligomers and/or polymers, each comprising at least one ethylenically unsaturated group accessible to a freeradical polymerization, (ii) at least one radiation-sensitive initiator or initiator system for free-radical polymerization absorbing radiation selected from the wavelength range of 300 to 1,200 nm; and (iii) at least one silsesquioxane comprising at least one substituent with at least one ethylenically unsaturated group each; applied onto the substrate.

Abstract: Lithographic printing plate precursor comprising: a) an untreated or pretreated substrate and b) a radiation-sensitive coating comprising: (i) at least one polymeric binder soluble or swellable in aqueous alkaline developers; (ii) at least one free-radical polymerizable monomer and/or oligomer comprising at least one non-aromatic C—C double bond and at least one SH group in the molecule; and (iii) a radiation-sensitive initiator or initiator system for free-radical polymerization, wherein component (ii) has the formula (I) wherein each R1a, R1b and R1c is independently selected from H, C1-C6 alkyl, C2-C8 alkenyl, aryl, halogen, CN and COOR1d, wherein R1d is H, C1-C18 alkyl, C2-C8 alkenyl, C2-C8 alkynyl or aryl; and Z is an aliphatic, heterocyclic or heteroaromatic spacer or a combination of two or more thereof, wherein Z can optionally comprise one or more additional SH groups and/or one or more additional non-aromatic C—C double bonds; and each Z1 is independently selected from a single bond, formulae (Ia),

Abstract: Initiator system comprising: (a) at least one substance capable of absorbing IR radiation, (b) at least one compound capable of forming free radicals, and (c) at least one 1,4-dihydropyridine derivative of the formula (I)

Abstract: Initiator system comprising: (a) at least one substance capable of absorbing IR radiation, (b) at least one compound capable of forming free radicals, and (c) at least one 1,4-dihydropyridine derivative of the formula (I) wherein R1 is selected from a hydrogen atom, —C(O)OR7, an optionally substituted alkyl group, an optionally substituted aryl group and an optionally substituted aralkyl group, R2 and R3 are independently selected from optionally substituted alkyl groups, optionally substituted aryl groups, CN and a hydrogen atom, R4 and R5 are independently selected from —C(O)OR7, —C(O)R7, —C(O)NR8R9 and CN, or R2 and R4 together form an optionally substituted phenyl ring or a 5- to 7-membered carbocyclic or heterocyclic ring, wherein the unit is present in the carbocyclic or heterocyclic ring adjacent to position 5 of the dihydropyridine ring and wherein the carbocyclic or heterocyclic ring optionally comprises additional substituents, or both R2 and R4 as well as R3 and R5 form either optiona

Abstract: Radiation-sensitive composition comprising: (a) one or more types of monomers and/or oligomers and/or polymers, each comprising at least one ethylenically unsaturated group accessible to a free-radical polymerization, (b) at least one sensitizer, (c) at least one coinitiator capable of forming free radicals together with the sensitizer (b) and selected from hexaarylbiimidazoles; and (d) optionally one or more components selected from alkali-soluble binders, dyes, exposure indicators, plasticizers, chain transfer agents, leuco dyes, surfactants, inorganic fillers and thermopolymerization inhibitors, characterized in that the at least one sensitizer is a 1,4-dihydropyridine derivative of the formula (I) which does not contain any nitro groups bonded to an aromatic ring.

Abstract: Heat-sensitive element comprising (a) an optionally pre-treated substrate (b) a positive working heat-sensitive coating comprising (i) at least one novolak resin, (ii) at least one component which reduces the aqueous alkaline developer solubility of novolak, wherein said reduction in solubility is reversed upon the application of heat, and (iii) at least one acidic polyvinyl acetal comprising the structural units (A), (B), (C) (A) (B) (C) and (D) wherein (D) is at least one unit selected from (D-1), (D-2), and (D-3): (D-1) (D-2) (D-3) wherein R1 is a hydrogen atom or a C1-C4 alkyl group, R2 is a hydrogen atom or a C1-C18 alkyl group, R3 is a hydrogen atom or a C1-C4 alkyl group, R4 is a hydrogen atom or a C1-C4 alkyl group, R5 is —COOH, —(CH2)a—COOH, —O—(CH2)a—COOH, —SO3H, —PO3H2 or —PO4H2, a is an integer from 1 to 8, and X is selected from —(CR6R7)n— and —CR8?CR9— wherein n is an integer of 1 to 6, each R6 and R7 is independently selected from a hydrogen atom and C1-C6 alkyl group, and R8 and R9 are indepen

Abstract: A single-step process for the production of meso-substituted cyanine dyes is provided comprising the reaction of a dye (III), with (a) a methylene compound (IV) or (V) or a quaternary salt (VI) or (VII) and (b) a compound selected from functionalized (hetero)aromatic compounds Ar—B, saturated cyclic amines (IV) and heteroaromatic compounds (V).

Abstract: The use of certain mercapto compounds as shelf life improvers for infrared-sensitive lithographic printing plate precursors is disclosed. The compounds are five-membered heteroaromatic rings containing a nitrogen atom and at least one other heteroatom, which can be oxygen, sulfur, or another nitrogen atom, such that two ring heteroatoms are bonded to a ring carbon bearing a thiol group.

Abstract: The present invention relates to IR-sensitive compositions containing an initator system comprising: (a) at least one compound capable of absorbing IR radiation selected from triarylamine dyes, thiazolium dyes, indolium dyes, oxazolium dyes, cyanine dyes, polyaniline dyes, polypyrrole dyes, polythiophene dyes and phthalocyanine pigments (b) at least one compound capable of producing radicals selected from polyhaloalkyl-substituted compounds (c) at least one polycarboxylic acid represented by the following formula I wherein Y is selected from the group consisting of O, S and NR7, each of R4, R5 and R6 is independently selected from the group consisting of hydrogen, C1-C4 alkyl, aryl which is optionally substituted, —COOH and NR8CH2COOH, R7 is selected from the group consisting of hydrogen, C1-C6 alkyl, —CH2CH2OH, and C1-C5 alkyl substituted with -COOH, R8 is selected from the group consisting of —CH2COOH, —CH2OH and —(CH2)2N(CH2COOH)2 and r is 0, 1, 2 or 3 with the proviso that at least one of R4, R5, R

Abstract: A method and an apparatus for the refreshment and reuse of loaded developers used in lithographic printing are disclosed. The pH of an aqueous, essentially silicate-free loaded developer is reduced to below about 11. Insoluble material is separated, and the pH increased to about 12.0 to 14.0 to produce a refreshed developer. The refreshed developer may be used to develop additional exposed printing plate precursors.

Abstract: The present invention relates to IR-sensitive compositions suitable for the manufacture of printing plates developable on-press. The IR-sensitive compositions comprise a first polymeric binder which does not comprise acidic groups having a pKa value?8; a second polymeric binder comprising polyether groups; an initiator system; and a free radical polymerizable system comprising at least one member selected from unsaturated free radical polymerizable monomers, free radical polymerizable oligomers and polymers containing C?C bonds in the back bone and/or in the side chain groups. The initiator system includes (i) at least one compound capable of absorbing IR radiation; (ii) at least one compound capable of producing radicals selected from polyhaloalkyl-substituted compounds; and (iii) at least one polycarboxylic acid of formula R4—(CR5R6)r—Y—CH2COOH, wherein oxi<redii+1.6 eV, where oxi=oxidation potential of component (i) in eV, and redii=reduction potential of component (ii) in eV.

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: 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: A method for the refreshment and reuse of loaded developers used in lithographic printing is disclosed. A polyoxyalkylene derivative is added to a silicate-containing loaded developer. Insoluble material is separated and the alkalinity level of the resulting essentially colorless liquid adjusted to produce a refreshed developer. The refreshed developer may be used to develop additional exposed imageable elements.