Radiation-sensitive composition containing a resole resin and a novolac resin and use thereof in lithographic printing plates
AssigneeEastman Kodak Company
InventorsNeil F. Haley, Steven L. Corbiere
Life of this patent
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Abstract
A radiation-sensitive composition especially adapted to prepare a lithographic printing plate that is sensitive to both ultraviolet and infrared radiation and capable of functioning in either a positive-working or negative-working manner is comprised of (1) a resole resin, (2) a novolac resin, (3) a latent Bronsted acid and (4) an infrared absorber. The solubility of the composition in aqueous alkaline developing solution is both reduced in exposed areas and increased in unexposed areas by the steps of imagewise exposure to activating radiation and heating.
Claims19
A method of forming a lithographic printing surface comprising the following steps carried out in the following order:
- (a) providing a lithographic printing plate comprising a support and an imaging layer containing an admixture of (1) a resole resin, (2) a novolac resin, (3) a latent Bronsted acid and (4) an infrared absorber;
- (b) imagewise exposing said lithographic printing plate to activating radiation;
- (c) heating said lithographic printing plate to provide reduced solubility in exposed areas and increased solubility in unexposed areas;
- and
- (d) contacting said lithographic printing plate with an aqueous alkaline developing solution to remove the unexposed areas thereof and thereby form a lithographic printing surface.
Dependencies are inferred from the claim text.