Patent ID: 10828884

Abstract:
Lithographic printing plate precursors are prepared with a unique substrate and one or more radiation-sensitive imageable layers. The substrate is prepared by two separate anodizing processes to provide an inner aluminum oxide layer having an average dry thickness (Ti) of 650-3,000 nm and a multiplicity of inner micropores having an average inner micropore diameter (Di) of ≤15 nm. A formed outer aluminum oxide layer comprises a multiplicity of outer micropores having an average outer micropore diameter (Do) of 15-30 nm; an average dry thickness (To) of 130-650 nm; and a micropore density (Co) of 500-3,000 micropores/μm2. The ratio of Do to Di is greater than 1.1:1, and Do in nanometers and the outer aluminum oxide layer micropore density (Co) in micropores/μm2, are further defined by the outer aluminum oxide layer porosity (Po) according to the following equation: 0.3≤Po≤0.8 where Po is 3.14(Co)(Do2)/4,000,000.