Abstract:
Lithographic printing plates can be prepared and made ready for lithographic printing without wet development or processing. A positive-working lithographic printing plate precursor is exposed to ablating infrared radiation of an energy of at least 1 J/cm 2 to form a lithographic printing plate ready for lithographic printing. The positive-working lithographic printing plate precursor has a hydrophilic aluminum substrate, and on the substrate, a crosslinked hydrophilic inner layer, and an oleophilic surface layer that is chemically bonded to the crosslinked hydrophilic inner layer. An intermediate layer provided between the crosslinked hydrophilic inner and oleophilic surface layers. Either this intermediate or the oleophilic surface layer, or both, generally includes an infrared radiation absorbing compound.
Abstract translation:可以制备平版印刷版,并准备好进行平版印刷,而无需湿法显影或加工。 将正性平版印刷版原版暴露于至少1J / cm 2的能量的消融红外辐射,以形成准备用于平版印刷的平版印刷版。 正性工程平版印刷版原版具有亲水性铝基材,并且在基材上具有交联的亲水性内层和与交联的亲水性内层化学键合的亲油性表面层。 提供在交联的亲水内亲和亲油表面层之间的中间层。 这种中间体或亲油性表面层,或两者都通常包括红外辐射吸收化合物。
Abstract:
Both positive-working and negative-working imageable element can have a radiation-sensitive imageable layer that has at least one pigment colorant that does not change color when heated, and at least one dye that can change color when heated. The dye is soluble in the solvent or mixture of solvents used to coat the radiation-sensitive imageable layer on a substrate and the pigment colorant is not. This combination of pigment colorant and dye provide excellent image contrast after imaging, development, and postbaking. The pigment colorant and the dye independently have a maximum absorption of from 480 to 700 nm.
Abstract:
Positive-working imageable elements can be imaged and processed using a processing solution that comprises at least 0.03 N of an organic amine or a mixture thereof, whose conjugated acids have a pKa greater than 9 and a boiling point greater than 150°C. The imageable element is a single-layer, infrared radiation-sensitive positive-working imageable element comprising a substrate and an infrared radiation absorbing compound. It also has an imageable layer that comprises a developability-enhancing compound and a poly(vinyl acetal) in which at least 25 mol % of its recurring units comprise pendant phenol, naphthol, or anthracenol groups that are substituted with one or more electron-withdrawing groups.
Abstract:
A negative-working imageable element has an imageable layer that includes an initiator composition including an iodonium cation and a borate anion, an infrared radiation absorbing compound, a particulate primary polymeric binder, and a phosphate (meth)acrylate adhesion promoter. The element also includes a polymeric overcoat disposed over the imageable layer and can be developed on-press to provide a lithographic printing plate with high run length. The element also has improved shelf-life.
Abstract:
A method for making a lithographic printing plate is disclosed which comprises the steps of: (1) providing a heat-sensitive lithographic printing plate precursor comprising on a support having a hydrophilic surface or which is provided with a hydrophilic layer, a heat-sensitive coating comprising an IR-absorbing agent and an alkaline soluble oleophilic resin whereof the solubility in an alkaline developing solution is reduced in the coating and whereof the solubility in an alkaline developing solution is increased upon heating or IR-radiation, (2) image-wise exposing said precursor with IR-radiation or heat, and (3) developing said image-wise exposed precursor with an alkaline developing solution and comprising an antisludge agent, characterised in that said antisludge agent is a heteroaromatic compound comprising at least one thiol group. According to the above method, the formation of sludge is inhibited or reduced.