Abstract: A negative-acting photolithographic printing plate precursor has a unique negative-acting photosensitive composition on a surface. The photosensitive composition contains an acetal polymer, an infrared absorbing dye or pigment, a crosslinking agent for the acetal resin and a photosensitive chemical acid progenitor, and the acetal polymer has within its backbone a structure comprising a particular polymeric moiety derived from a polyvinyl alcohol backbone.

Abstract: A negative-acting photolithographic printing plate precursor has a unique negative-acting photosensitive composition on a surface. The photosensitive composition contains an acetal polymer, an infrared absorbing dye or pigment, a crosslinking agent for the acetal resin and a photosensitive chemical acid progenitor, and the acetal polymer has within its backbone a structure comprising a particular polymeric moiety derived from a polyvinyl alcohol backbone.

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: A positive-working radiation-sensitive composition for use with a radiation source comprises one or more polymers capable of being eluted in an alkaline aqueous solution and a development-enhancing compound. The invention provides a positive-working photosensitive composition of good sensitivity for use with one or both of ultra-violet radiation and an infrared laser radiation source. The composition is stable in its state before exposure and has an excellent handling property. The sensitivity of a radiation-sensitive coating based on the composition of this invention is increased without compromising the handling characteristics. Radiation-sensitive elements based on the composition of the invention have good development latitude. A positive-working lithographic printing precursor is based on the radiation-sensitive composition coated on a hydrophilic surface.

Abstract: A gravure printing element is fabricated using a negative-working thermally-imageable coating that is exposed using commercially available diode lasers, the coating being insensitive to ultraviolet light, daylight or visible light, and developable using aqueous media. A gravure etch mask is formed on a printing precursor by applying a coating of thermally-imageable material, curing the coating, imagewise illuminating the cured coating with a laser and removing with a developer the areas of the coating that were not illuminated. The masked precursor is then chemically etched to produce a gravure printing element.

Abstract: A positive-working radiation-sensitive composition for use with a radiation source comprises one or more polivinyl acetal polymers capable of being dissolved in an alkaline aqueous solution and a development-enhancing compound. The sensitivity of a radiation-sensitive coating based on the composition of this invention is increased without compromising the handling characteristics. Radiation-sensitive elements based on the composition of the invention have good development latitude. A positive-working lithographic printing precursor is based on the radiation-sensitive composition coated on a hydrophilic surface. The precursor is developable using an alkaline aqueous solution, and may be used with a radiation source in lithographic applications, such as conventional imaging systems, computer-to-plate systems or other direct imaging applications. The precursor is stable in its state before exposure and has an excellent handling property.