Patent ID: 7205084

Claim:
A positive-working heat-sensitive lithographic printing plate precursor comprising a support having a hydrophilic surface or which is provided with a hydrophilic layer and an oleophilic coating provided on the support, said coating comprising an infrared light-to-heat converter and an alkali-soluble phenolic resin, wherein the phenyl group of the phenolic monomeric unit of said phenolic resin is (a) chemically modified with an organic substituent comprising a group having the chemical structure of Formula I: wherein n is 0, 1, 2 or 3, wherein each R 1 is selected from hydrogen, an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group, —SO 2 —NH—R 2 , —NH—SO 2 —R 4 , —CO—NR 2 —R 3 , —NR 2 —CO—R 4 , —O—CO—R 4 , —CO—O—R 2 , —CO—R 2 , —SO 3 —R 2 , —SO 2 —R 2 , —SO—R 4 , —P(═O)(—O—R 2 )—(—O—R 3 ), —NR 2 —R 3 , —O—R 2 , —S—R 2 , —CN, —NO 2 , a halogen, —N-phthalimidyl, —M—N-phthalimidyl, or —M—R 2 , wherein M represents a divalent linking group containing 1 to 8 carbon atoms, wherein R 2 , R 3 , R 5 and R 6 are independently selected from hydrogen or an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group, wherein R 4 is selected from an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclic, aryl, heteroaryl, aralkyl or heteroaralkyl group, or wherein at least two groups selected from each R 1 to R 4 together represent the necessary atoms to form a cyclic structure, or wherein R 5 and R 6 together represent the necessary atoms to form a cyclic structure, or (b) substituted with a group having the structure —N═N—O, wherein the —N═N— group is covalently bound to a carbon atom of the phenyl group and wherein O is an aromatic group, wherein said coating further comprises a polymeric development accelerator, and wherein said polymeric development accelerator is a phenolic formaldehyde resin comprising at least 70 mol % of meta-cresol as a recurring monomeric unit.