Abstract: A lithographic printing plate precursor comprising a coating provided on a support having a hydrophilic surface, the coating containing thermoplastic polymer particles and an IR-dye characterized in that the IR-dye contains a structural element according to Formula I wherein A represents hydrogen, halogen or a monovalent organic group; Y and Y? independently represent —CH— or —N—; R1 and R2 independently represent hydrogen, an optionally substituted alkyl or aryl group or represent the necessary atoms to form a ring; * represents the linking positions to the rest of the molecule.

Abstract: A method for preparing a colour laser marked article comprising the steps of: a) infrared laser marking a security element including a polymeric support and a colour forming layer comprising a colour forming compound, an infrared dye and a polymeric binder comprising vinyl acetate and at least 85 wt % of vinyl chloride based on the total weight of the binder; and b) exposing the laser marked security element with light having a wavelength higher than 440 nm. The light exposure of step b) hinders the falsification of an issued security document without significant increase of background density.

Abstract: a method for preparing a lithographic printing plate that includes imagewise exposing a lithographic printing plate precursor comprising a coating provided on a support having a hydrophilic surface, the coating containing thermoplastic polymer particles and an infrared radiation absorbing dye characterized in that the coating further comprises a phenolic stabilizer.

Abstract: A lithographic printing plate precursor includes a cyanine dye, characterized in that the cyanine dye includes two different chromophoric groups, a chromophoric group that has its main absorption in the infrared region and another chromophoric group that has its main absorption in the visible light region.

Abstract: A lithographic printing plate precursor comprising an image-recording layer, said image-recording layer being photopolymerizable upon exposure to light having a wavelength of from 300 to 500 nm and containing a mixture of sensitizers.

Abstract: A method of colour laser marking a security document precursor including, in order, at least: a) a polymeric foil; b) at least one colourless colour forming layer for generating a colour different from black containing at least an infrared absorber, a colour forming compound and a polymeric binder; and c) either a lasermarkable polymeric support or a lasermarkable layer for generating a black colour; comprising the steps of: (1) laser marking a colour different from black in the colourless colour forming layer with an infrared laser used in continuous wave mode; and (2) laser marking a black colour by carbonization in the lasermarkable polymeric support or the lasermarkable layer with the same infrared laser used in a pulsed mode; and wherein at least one of the polymeric foil and the lasermarkable polymeric support is transparent for the infrared light of the infrared laser.

Abstract: A security document precursor including, in order, at least: a) a transparent biaxially stretched polyethylene terephthalate foil; b) a colourless colour forming layer containing at least an infrared absorber, a colour forming component and a polymeric binder; and c) a polymeric support; wherein the colourless colour forming layer contains at least one component forming a compound having a melting temperature of less than 20° C. upon laser marking the colourless colour forming layer with an infrared laser. Methods for securing a security document using the security document precursor are also disclosed.

Abstract: A method of colour laser marking an article having a polymeric foil with at least one colourless layer containing an infrared absorber, a polymeric binder and a colour forming compound; including the steps of:—laser marking the colourless layer with an infrared laser using a first laser operation mode to generate a blue or cyan colour; and—laser marking the same colourless layer with an infrared laser using a second laser operation mode to generate a black colour, wherein the first laser operation mode applies less energy to the colourless layer than the second laser operation mode.

Abstract: A security document precursor including, in order: a) at least one transparent biaxially stretched polyester foil; b) one colourless colour forming layer containing at least an infrared absorber, a colourless dye-precursor and a polymeric binder; and c) a polymeric support; wherein the polymeric binder is copolymer including at least 90 wt % of a chlorinated ethylene and 1 wt % to 10 wt % of vinyl acetate both based on the total weight of the binder. Methods for making the security document precursor are also disclosed.

Abstract: A lithographic printing plate precursor comprising an image-recording layer, said image-recording layer being photopolymerizable upon exposure to light having a wavelength of from 300 to 500 nm and containing a mixture of sensitizers.

Abstract: A heat-sensitive negative-working lithographic printing plate precursor comprising: a support having a hydrophilic surface or which is provided with a hydrophilic layer; and an image-recording layer comprising hydrophobic thermoplastic polymer particles, an infrared light absorbing dye and a dye; wherein said dye has a specified structure and a most bathochromic light absorption peak between 451 nm and 750 nm.

Abstract: A heat-sensitive negative-working lithographic printing plate precursor comprising: a support having a hydrophilic surface or which is provided with a hydrophilic layer; and an image-recording layer comprising hydrophobic thermoplastic polymer particles and an infrared light absorbing dye; characterized in that: said image-recording layer further comprises a compound, said compound comprising an aromatic moiety and at least one acidic group or salt thereof and having a most bathochromic light absorption peak at a wavelength between 300 nm and 450 nm.

Abstract: A lithographic printing plate precursor includes a cyanine dye, characterized in that the cyanine dye includes two different chromophoric groups, a chromophoric group that has its main absorption in the infrared region and another chromophoric group that has its main absorption in the visible light region.

Abstract: A heat-sensitive imaging element includes an IR dye, and more particularly a heat-sensitive lithographic printing plate precursor includes the IR dye. A method for making the lithographic printing plate produces a print-out image of high contrast upon exposure to IR-radiation or heating.

Abstract: A heat-sensitive imaging element includes an IR dye having a structure according to Formula I, wherein at least one of the Rd groups is a group which is transformed by a chemical reaction, induced by exposure to IR-radiation or heat, into a group which is a stronger electron-donor than the Rd; or wherein at least one of the Ra groups is a group which is transformed by a chemical reaction, induced by exposure to IR-radiation or heat, into a group which is a stronger electron-acceptor than the Ra. The imaging element is able to form a visible print-out image with a high contrast directly after image-wise exposure by IR-radiation or heating.

Abstract: A lithographic printing plate precursor comprising a coating provided on a support having a hydrophilic surface, the coating containing thermoplastic polymer particles and an infrared radiation absorbing dye characterized in that the coating further comprises a phenolic stabilizer.

Abstract: A lithographic printing plate precursor comprising a coating provided on a support having a hydrophilic surface, the coating containing thermoplastic polymer particles and an IR-dye characterized in that the IR-dye contains a structural element according to Formula I wherein A represents hydrogen, halogen or a monovalent organic group; Y and Y? independently represent —CH— or —N—; R1 and R2 independently represent hydrogen, an optionally substituted alkyl or aryl group or represent the necessary atoms to form a ring; * represents the linking positions to the rest of the molecule.

Abstract: A lithographic printing plate precursor includes a coating provided on a support having a hydrophilic surface, the coating containing thermoplastic polymer particles and an infrared radiation absorbing dye characterized in that the dye contains a substituent selected from bromo and iodo.

Abstract: The present invention provides new intermediate compounds enabling the preparation of N-meso substituted cyanine, merocyanine or oxonole dyes wherein the N-meso substituent comprises electron withdrawing groups and wherein such N-meso substituents are introduced at the intermediate level. These intermediates enable the formation of dyes having in the meso-position N-substituents comprising electron withdrawing groups without the need for further derivatization of the meso-substituent at the dye level.

Abstract: A heat-sensitive imaging element includes an IR dye having a structure according to Formula I, wherein at least one of the Rd groups is a group which is transformed by a chemical reaction, induced by exposure to IR-radiation or heat, into a group which is a stronger electron-donor than the Rd; or wherein at least one of the Ra groups is a group which is transformed by a chemical reaction, induced by exposure to IR-radiation or heat, into a group which is a stronger electron-acceptor than the Ra. The imaging element is able to form a visible print-out image with a high contrast directly after image-wise exposure by IR-radiation or heating.