Abstract: A positive-working lithographic printing plate precursor has an outermost imageable layer that is present at a dry coverage weight of at least 0.7 g/m2 and up to and including 1.6 g/m2 and comprises a primary polymeric binder comprising recurring units of a hydroxyaryl acetal or a hydroxyaryl ester, or recurring units of both a hydroxyaryl acetal and a hydroxyaryl ester. The outermost imageable layer also contains an alkali-soluble secondary vinyl polymer that is not a primary polymeric binder and a non-polymeric polyhydric phenol. These precursors comprise an infrared radiation absorber to make them sensitive and imageable using infrared radiation. After imaging, the precursors can be processed (developed) using an relatively low pH developer such as a silicate- or metasilicate-free developer.

Abstract: A positive-working lithographic printing plate precursor has an outermost imageable layer that is present at a dry coverage weight of at least 0.7 g/m2 and up to and including 1.6 g/m2 and comprises a primary polymeric binder comprising recurring units of a hydroxyaryl acetal or a hydroxyaryl ester, or recurring units of both a hydroxyaryl acetal and a hydroxyaryl ester. The outermost imageable layer also contains an alkali-soluble secondary vinyl polymer that is not a primary polymeric binder and a non-polymeric polyhydric phenol. These precursors comprise an infrared radiation absorber to make them sensitive and imageable using infrared radiation. After imaging, the precursors can be processed (developed) using an relatively low pH developer such as a silicate- or metasilicate-free developer.

Abstract: Positive-working imageable elements having improved sensitivity, high resolution, and solvent resistance are prepared using a water-insoluble polymeric binder comprising vinyl acetal recurring units that have pendant hydroxyaryl groups, and recurring units comprising carboxylic acid aryl ester groups that are substituted with a cyclic imide group. These imageable elements can be imaged and developed to provide various types of elements including lithographic printing plates.

Abstract: A method of making imaged elements such as lithographic printing plates is achieved by imagewise exposing a positive-working imageable element using energy of less than 300 mJ/cm2 to provide exposed and non-exposed regions. The imaged element is developed using an alkaline, silicate-free solution containing a carbonate to remove predominantly only the exposed regions to provide an image. The imageable element comprises a substrate and a radiation absorbing compound, and has an imageable layer on the substrate that comprises a developability-enhancing compound and a poly(vinyl acetal) in which at least 25 mol % of its recurring units comprise pendant nitro-substituted phenolic groups.

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 radiation-sensitive composition can be used to prepare positive-working imageable elements having improved sensitivity and solvent resistance. These elements are useful for making lithographic printing plates and printed circuit boards. The composition includes a water-insoluble polymeric binder that has at least 20 mol % of recurring units comprising hydroxyaryl carboxylic acid ester groups, some of which can be substituted with cyclic imide moieties.

Abstract: Positive-working imageable elements having improved sensitivity, high resolution, and solvent resistance are prepared using a water-insoluble polymeric binder comprising vinyl acetal recurring units that have pendant hydroxyaryl groups, and recurring units comprising carboxylic acid aryl ester groups that are substituted with a cyclic imide group. These imageable elements can be imaged and developed to provide various types of elements including lithographic printing plates.

Abstract: A radiation-sensitive composition can be used to prepare positive-working imageable elements having improved sensitivity and solvent resistance. These elements are useful for making lithographic printing plates and printed circuit boards. The composition includes a water-insoluble polymeric binder that has at least 20 mol % of recurring units comprising hydroxyaryl carboxylic acid ester groups, some of which can be substituted with cyclic imide moieties.

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 method of making imaged elements such as lithographic printing plates is achieved by imagewise exposing a positive-working imageable element using energy of less than 300 mJ/cm2 to provide exposed and non-exposed regions. The imaged element is developed using an alkaline, silicate-free solution containing a carbonate to remove predominantly only the exposed regions to provide an image. The imageable element comprises a substrate and a radiation absorbing compound, and has an imageable layer on the substrate that comprises a developability-enhancing compound and a poly(vinyl acetal) in which at least 25 mol % of its recurring units comprise pendant nitro-substituted phenolic groups.

Abstract: Radiation-sensitive compositions can be used to prepare positive-working imageable elements useful for example to make lithographic printing plates. The compositions include an aqueous alkaline solvent soluble polymeric binder that includes a phenolic resin (such as a novolak) or a poly(vinyl acetal). The compositions also include a developability-enhancing composition comprising one or more basic nitrogen-containing organic compounds. The radiation-sensitive composition can be coated as an imageable layer that further includes a radiation absorbing compound that is, for example, sensitive to infrared radiation.

Abstract: Radiation-sensitive compositions can be used to prepare positive-working imageable elements useful for example to make lithographic printing plates. The compositions include an aqueous alkaline solvent soluble polymeric binder that includes a phenolic resin (such as a novolak) or a poly(vinyl acetal). The compositions also include a developability-enhancing composition comprising one or more basic nitrogen-containing organic compounds. The radiation-sensitive composition can be coated as an imageable layer that further includes a radiation absorbing compound that is, for example, sensitive to infrared radiation.