Abstract:
Negative-working imageable elements have a hydrophilic substrate and a single thermally-sensitive imageable layer. This layer can include an infrared radiation absorbing compound and polymeric particles that coalesce upon thermal imaging. These coalesceable polymeric particles comprise a thermoplastic polymer and a colorant to provide improved visible contrast between exposed and non-exposed regions in the imaged element, such as lithographic printing plates.
Abstract:
Images can be provided using a method comprising thermally imaging a negative-working imageable element to provide an imaged element with exposed regions and non-exposed regions, the exposed regions consisting essentially of coalesced core-shell particles, and developing the imaged element on-press to remove only the non-exposed regions using a lithographic printing ink, fountain solution, or both. The imageable element comprises a single thermally-sensitive imageable layer consisting essentially of an infrared radiation absorbing compound and core-shell particles that coalesce upon thermal imaging. The core of the core-shell particles is composed of a hydrophobic thermoplastic polymer, the shell of the core-shell particles is composed of a hydrophilic polymer that is covalently bonded to the core hydrophobic thermoplastic polymer, and the thermally-sensitive imageable layer comprises less than 10 weight % of free polymer.
Abstract:
A lithographic printing plate precursor comprises an imagable layer comprising a free radically polymerizable component, an initiator composition capable of generating free radicals upon exposure to imaging infrared radiation, an infrared radiation absorbing dye comprising an infrared radiation absorbing cation and a counter anion, and a polymeric binder. The salt formed between the infrared radiation absorbing cation and a tetraphenyl borate has solubility in 2-methoxy propanol at 20° C. that is greater than or equal to 3.5 g/l. The use of these infrared radiation absorbing dyes in the imagable layers provides a reduced tendency of these dyes to crystallize in the presence of tetraaryl borate counter anions.
Abstract:
Imageable elements can be imaged and then processed using a solution containing core-shell particles that are designed to complex with non-coalesced particles in the non-exposed regions of imaged element. A separate development step is not needed, but the non-coalesced particles and complexed core-shell particles can be removed from the resulting printing plate before using the resulting lithographic printing plate for printing.
Abstract:
Lithographic printing plates are prepared by imaging and developing negative-working lithographic printing plate precursors that include certain particulate polymeric binders in the photosensitive imageable layer. Such particulate polymeric binders are poly(urethane-acrylic) hybrids. Development is carried out using a working strength developer that includes one or more organic solvents in a total amount of at least 7 weight % and an anionic surfactant in an amount of at least 5 weight %.
Abstract:
Negative-working imageable elements have a hydrophilic substrate and a single thermally-sensitive imageable layer. This layer can include an infrared radiation absorbing compound and polymeric particles that coalesce upon thermal imaging. These coalesceable polymeric particles comprise a thermoplastic polymer and a colorant to provide improved visible contrast between exposed and non-exposed regions in the imaged element, such as lithographic printing plates.
Abstract:
A lithographic printing plate precursor comprises an imageable layer comprising a free radically polymerizable component, an initiator composition capable of generating free radicals upon exposure to imaging infrared radiation, an infrared radiation absorbing dye that is defined by Structure (I) shown in the disclosure, which dyes comprise one or more ethylenically unsaturated polymerizable groups in an organic group that is attached to the methine chain. These infrared radiation absorbing dyes exhibit a reduced tendency to crystallize in the imageable layers in the presence of tetraaryl borate counter anions and therefore provide improved shelf life.
Abstract:
Imaged lithographic printing plates are processed using a developer that is replenished with only water, but replenishment is at a rate to allow developer volume to slowly decrease from a developer reservoir. This allows for a longer processing cycle especially when the developer is supplied from a container having a defined amount and applied using spray devices where water evaporation from the developer can be significant. Water lost by evaporation is replenished while water carried out by lithographic printing plates is not replenished.
Abstract:
A lithographic printing plate precursor can be used to prepare a printing plate using thermal ablation. The precursor has a non-thermally ablatable first layer on a substrate. Over the first layer is a thermally ablatable outer layer that includes an IR absorbing compound in an ablatable polymeric binder. The first layer includes a sol gel as a continuous inorganic matrix and a discontinuous inorganic phase (inorganic particles) dispersed therein.
Abstract:
The present invention provides a positive-working, thermally imageable element generally comprising a multi-layered imageable coating. The invention provides an imageable element comprising a substrate, an ink-receptive top layer, and an underlayer, the underlayer including a specific copolymer described herein. The copolymer can be a polymer comprising constitutional units derived from: a) a monomer having a cyclic urea group; b) a monomer comprising an N-substituted maleimide; c) a (meth)acrylamide or (meth)acrylate monomer; and d) a (meth)acrylic acid or vinyl benzoic acid monomer. In another embodiment, the copolymer can be a polymer comprising constitutional units derived from: a) a monomer having a cyclic urea group; b) a (meth)acrylic acid or vinyl benzoic acid monomer; c) and a (meth)acrylonitrile monomer. The imageable element may be used to prepare a lithographic printing plate that is resistant to press chemistry and can optionally be baked to increase press runlength.