Abstract: A radiation-sensitive composition, positive-working coating compositions useful for the preparation of lithographic printing plates and lithographic printing plate precursors comprising the composition are disclosed. The composition comprises at least one quinonediazide compound and at least one carboxylic copolymer. The compositions produce lithographic printing plates that show high print run stability.

Abstract: The present invention provides a photosensitive lithographic printing plate with a long press life, high sensitivity, and excellent storage stability, and a photosensitive composition for a lithographic printing plate for producing such a photosensitive lithographic printing plate. The photosensitive composition for the lithographic printing plate includes (A) a binder resin, (B) a diazo resin, (C) a monomer or oligomer, a molecule of which has at least two polymerizable ethylenically unsaturated double bonds, (D) a photopolymerization initiator, (E) an o-tert-butylphenol derivative, and (F) a 2-mercaptoimidazole derivative such as 2-mercaptobenzimidazole.

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: The present invention also includes an imageable element, comprising a substrate and a thermally imageable composition comprising a thermally sensitive polymer which exhibits an increased solubility in an aqueous developer solution upon heating. The thermally sensitive polymer includes at least one covalently bonded unit and at least one thermally reversible non-covalently bonded unit, which includes a two or more centered H-bond within each of the non-covalently bonded unit. The present invention also includes a method of producing the imaged element. The present invention still further includes a thermally imageable composition comprising comprising a thermally sensitive polymer according to the present invention and a process for preparing the thermally sensitive polymer, which is a supramolecular polymer.

Abstract: Infra-red absorbing polymers useful in imageable products and the lithographic printing field comprise infra-red absorbing groups carried as pendent groups on a polymer backbone. Certain infra-red absorbing groups may also act to insolublize the polymer in a developer, until it is imagewise exposed to infra-red radiation. The resulting heat renders the polymer soluble in the developer. Imagable products employing the infra-red absorbing polymers may include positive working lithographic printing plates.

Abstract: The present invention includes a method of preparing an inkjet ink imaged lithographic printing plate, comprising the steps of: imagewise applying onto a substrate coated with an inkjet ink reactive coating composition comprising a diazonium material, an inkjet ink to produce an imaged coated substrate wherein the inkjet ink imaged regions are oleophilic and more developer-insoluble than non-imaged regions; and contacting said imaged and non-imaged regions of said an imaged coated substrate and an aqueous developer to selectively remove said coating from said developer soluble non-imaged regions. The present invention also includes a lithographic printing plate, such as an inkjet ink imaged lithographic printing plate, which is prepared by the method of the present invention.

Abstract: A method for applying a matting layer to a radiation-sensitive layer of a printing plate precursor is disclosed. The method comprises: (a) providing a matting composition comprising a polymer and a solvent, wherein the matting composition has a solid content of more than 10% and no more than 50% by weight based on the total composition; and (b) spraying the matting composition on the radiation-sensitive layer using an electrostatically aided rotary atomizer having a bell speed of more than 10,000 rpm, wherein the distance between the bell and the radiation-sensitive layer to be coated is less than 30 cm. The printing plate precursor may be in the form of a moving web. The method of the present invention can be used for matting any kind of radiation-sensitive layer of conventional positive and negative working lithographic printing plate precursors.

Abstract: Thermally imageable lithographic printing plate precursors and heat-sensitive compositions for use in these printing plate precursors are disclosed. The compositions contain an aqueous developer soluble polymer, such as a phenolic resin; a compound that reduces the aqueous developer solubility of the polymer; and optionally, and infrared absorber. Examples of compounds that reduce the aqueous developer solubility of the polymer are those that contain at least one quarternized nitrogen atom, such as quinolinium compounds, benzothiazolium compounds, pyridinium compounds, and imidazoline compounds. On thermal imaging, the irradiated areas become more soluble in the aqueous developer and can be removed to form a positive image.

Abstract: The present invention includes a radiation-imageable element for lithographic printing having a hydrophilic anodized aluminum base with a surface having pores and a image-forming layer having polymer particles coated on the aluminum base. The ratio of the average pore diameter to the average particle diameter is from 0.4:1 to 10:1. The present invention further includes a method of producing the imaged element. The method includes the steps of imagewise exposing the radiation-imageable element to radiation to produce exposed and unexposed regions and contacting the imagewise exposed radiation-imageable element and a developer to remove the exposed or the unexposed regions.

Abstract: The invention provides a lithographic printing for precursor having an imagable coating on an aluminum support, wherein the imagable coating comprises a polymeric substance comprising colorant groups, and wherein the aluminum support on which the coating is provided is anodized but not subsequently modified by means of a post-anodic treatment compound, and the coating does not comprise a colorant dye. The polymeric substance may also comprise pendent infra-red or developer dissolution inhibiting groups, and these groups may also be the colorant groups themselves.

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 positive-working elements such as lithographic printing plates that can be adapted to direct-to-plate imaging procedures. The weight ratio of infrared radiation absorbing compound to diazonaphthoquinone moiety is less than 1:14.

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: Polymeric compounds for lithographic printing plates, especially plates for use in printing utilizing UV curable inks, may include a structural unit (I) wherein R1 represents an optionally-substituted cyclic or alkyl group, x represents 0 or 1 and A represents an optionally-substituted alkylene group. A range of compounds having different solubilities in selected solvents may be prepared by varying the identity or group R1. Such components may be prepared by reacting an amine of formula R1NH2 with the maleic anhydride derivative corresponding to moiety 1.

Abstract: Radiation-sensitive compositions comprise at least one novolak, at least one naphthoquinone diazide derivative and a copolymer; the copolymer consisting of the units A, B and C wherein unit A is present in an amount of 5 to a maximum of 50 mol % and R1 and R4 are selected such that the homopolymer of A is alkali-soluble, B is present in an amount of 20 to 70 mol % and R2, R6 and R7 are selected such that the homopolymer of B has a high glass transition temperature, and C is present in an amount of 10 to 50 mol % and R3 and R5 are selected such that the homopolymer of C is water-soluble and that unit A is different from unit C. Furthermore, the invention describes printing plates produced therefrom.

Abstract: The present invention includes a two-layer imageable element, including: a substrate, a top layer including a first thermally imageable composition including (a) a first thermally sensitive supramolecular polymer or (b) a thermally imageable composition free of the first thermally sensitive supramolecular polymer; and disposed between the substrate and the top layer, a bottom layer including a second thermally imageable composition, which includes a second thermally sensitive supramolecular polymer. The present invention also includes a method of producing the imaged element.

Abstract: A printing plate is prepared by the method comprising: (a) providing a substrate; and (b) applying by ink jetting to the substrate a fluid composition comprising an acidic polymeric compound, in which the acid groups of the acidic polymeric compound are at least partially neutralized with base, providing a printing plate that is ready-to-use on a press without having to develop it. The printing plate of this invention is capable of extended press run length and advantageously avoids the need of chemical development.

Abstract: A printing plate is prepared by the process including: (a) providing a substrate; and (b) applying by ink jetting to the substrate a fluid composition comprising a compound which comprises at least one nitrogen-containing heterocyclic moiety, providing a printing plate that is ready-to-use on a press without having to develop it. The printing plate of this invention is capable of extended press run length and advantageously avoids the need of chemical development.

Abstract: The present invention includes an imageable element, comprising a substrate and a thermally imageable composition which includes a graft copolymer having hydrophobic and hydrophilic segments. Upon imagewise exposure to thermal energy, the graft copolymer produces exposed regions that are less soluble in a developer than the unexposed regions. Also included is a method of producing an imaged element which includes a graft copolymer according to the present invention.

Abstract: A method for producing printing plate precursors by dual-feed technology is described. The obtained printing plate precursors contain polymer particles in the photosensitive layer and show high print run stability.

Abstract: The present invention also includes an imageable element, comprising a substrate and a thermally imageable composition comprising a thermally sensitive polymer which exhibits an increased solubility in an aqueous developer solution upon heating. The thermally sensitive polymer includes at least one covalently bonded unit and at least one thermally reversible non-covalently bonded unit, which includes a two or more centered H-bond within each of the non-covalently bonded unit. The present invention also includes a method of producing the imaged element. The present invention still further includes a thermally imageable composition comprising comprising a thermally sensitive polymer according to the present invention and a process for preparing the thermally sensitive polymer, which is a supramolecular polymer.