Planographic printing plate precursor having an image-recording layer containing an infrared ray absorbent, a polymerization initiator, a polymerizable compound, and a thiol compound

1 . A planographic printing plate precursor, comprising a support and, on the support, an image-recording layer containing an infrared ray absorbent, a polymerization initiator, a polymerizable compound, and a thiol compound.

2 . The planographic printing plate precursor of claim 1 , flyer comprising a protective layer on the image-recording layer.

3 . The planographic printing plate precursor of claim 2 , wherein the protective layer contains a lamellar inorganic compound.

4 . The planographic printing plate precursor of claim 1 , wherein the thiol compound is represented by the following Formula (I):

wherein in Formula (I), R represents an alkyl group that may have a substituent or an aryl group that may have a substituent, A represents an atomic group which, together with a N═C—N portion, forms a five- or six-membered carbon atom-containing heterocyclic ring and, and A may have a substituent.

5 . The planographic printing plate precursor of claim 4 , wherein the thiol compound is a compound represented by the following Formulae (II) or (III):

wherein in Formulae (II) and (III), R represents an alkyl group that may have a substituent or an aryl group that may have a substituent; and X represents a halogen atom, an alkoxyl group, an alkyl group that may have a substituent, or an aryl group that may have a substituent.

6 . The planographic printing plate precursor of claim 1 , wherein the thiol compound is at least one of the following compounds.

7 . The planographic printing plate precursor of claim 1 , wherein the image-recording layer further contains a binder polymer.

8 . The planographic printing plate precursor of claim 7 , wherein the binder polymer has a side chain containing a cross-linkable group.

9 . The planographic printing plate precursor of claim 8 , wherein the crosslinkable group is an ethylenically unsaturated bond group.

10 . The planographic printing plate precursor of claim 9 , wherein the ethylenically unsaturated bond group is a group represented by any one of the following Formulae (A) to (C):

wherein in Formula (A), R 1 to R 3 independently represent a hydrogen atom or a monovalent substituent composed of at least one non-metal atom; X represents an oxygen or a sulfur atom, or —N(R 12 )—; and R 12 represents a hydrogen atom or a monovalent organic group;

wherein in Formula (B), R 4 to R 8 independently represent a hydrogen atom or a monovalent substituent group composed of at least one non-metal atom; Y represents an oxygen or a sulfur atom, or —N (R 12 )—; and R 12 represents a hydrogen atom or a monovalent organic group; and

wherein in Formula (C), R 9 to R 11 independently represent a hydrogen atom or a monovalent substituent group composed of at least one non-metal atom; Z represents an oxygen or a sulfur atom, or —N (R 13 )—; and R 13 represents an alkyl group that may have a substituent.