Abstract: A radiation-sensitive medium comprises hydrophilic polymer particles, the particles comprising a thermally softenable hydrophobic polymer, a hydrophilic polymer and a bonding compound capable of chemically bonding to the hydrophobic polymer and to the hydrophilic polymer. The radiation-sensitive medium further may comprise a substance capable of converting radiation into heat. The radiation-sensitive medium is aqueous-ineluable when coated and dried, and becomes hydrophobic under the action of heat. The polymer particles are made by polymerization of at least one hydrophobic monomer and at least one bonding compound in the presence of the hydrophilic polymer. The radiation-sensitive medium may be provided as a coatable composition to be applied to substrates to form a processless radiation-imageable lithographic printing precursor, which may further be provided with an aqueous eluable hydrophilic overcoat.

Abstract: A radiation-sensitive medium comprises hydrophilic polymer particles, the particles comprising a thermally softenable hydrophobic polymer, a hydrophilic polymer and a bonding compound capable of chemically bonding to the hydrophobic polymer and to the hydrophilic polymer. The radiation-sensitive medium further may comprise a substance capable of converting radiation into heat. The radiation-sensitive medium is aqueous-ineluable when coated and dried, and becomes hydrophobic under the action of heat. The polymer particles are made by polymerization of at least one hydrophobic monomer and at least one bonding compound in the presence of the hydrophilic polymer. The radiation-sensitive medium may be provided as a coatable composition to be applied to substrates to form a processless radiation-imageable lithographic printing precursor, which may further be provided with an aqueous eluable hydrophilic overcoat.

Abstract: An aqueous alkaline developer for use with an imaged lithographic printing precursor comprises an aqueous alkaline medium, sodium metasilicate, a steric or electrosteric stabilizer, and a rinse aid or a phase stabilizer. It is suited for developing a lithographic printing precursor comprising, on a substrate, a coated and dried layer of a radiation-sensitive composition comprising one or more acetal resins. The developer may further contain a moderator, a dispersing agent capable of solvating a hydrophobic image colorant, and a wetting agent. The acetal resin of the precursor may be derived from polyvinyl alcohol by condensation with aldehydes. The imageable element is imageable by radiation, preferably infrared radiation, and provides good sensitivity for use in lithographic applications, such as conventional imaging systems, computer-to-plate systems or other direct imaging elements and applications when treated with the developer.