Infrared-sensitive planographic printing plate precursor

1 . An infrared-sensitive planographic printing plate precursor comprising:

a support;

a recording layer on one surface of the support, which recording layer contains a water-insoluble and alkali-soluble resin, an infrared absorber and a long-chain alkyl group-containing polymer, and is capable of forming an image by infrared irradiation; and

a back coating layer on the other surface of the support, which back coating layer contains an organic polymer and has a thickness of 0.3 μm or more.

2 . The infrared-sensitive planographic printing plate precursor of claim 1 , wherein:

the recording layer has a multi-layered structure comprising a lower layer containing the water-insoluble and alkali-soluble resin, and an uppermost layer containing the water-insoluble and alkali-soluble resin and the long-chain alkyl group-containing polymer; and

at least one of the lower layer and/or the uppermost layer contains the infrared absorber.

3 . The infrared-sensitive planographic printing plate precursor of claim 1 , wherein the long-chain alkyl group-containing polymer is a copolymer of at least a monomer having a long-chain alkyl group and a vinyl monomer having a carboxyl group.

4 . The infrared-sensitive planographic printing plate precursor of claim 1 , wherein a long-chain alkyl group contained in the long-chain alkyl group-containing polymer has 6 or more carbon atoms.

5 . The infrared-sensitive planographic printing plate precursor of claim 1 , wherein the recording layer contains particles of the long-chain alkyl group-containing polymer, and projections are formed of the particles on a surface of the recording layer.

6 . The infrared-sensitive planographic printing plate precursor of claim 5 , wherein an average particle diameter of the particles is 0.05 to 50 μm.

7 . The infrared-sensitive planographic printing plate precursor of claim 1 , wherein the recording layer contains the long-chain alkyl group-containing polymer in an amount of 0.5 to 30% by mass based on the total solid matter of the recording layer.

8 . An infrared-sensitive planographic printing plates precursor comprising:

a support;

a recording layer on one surface of the support, which recording layer contains a water-insoluble and alkali-soluble resin and an infrared absorber, and is capable of forming an image by infrared irradiation; and

an organic polymer layer on the other surface of the support, which organic polymer layer contains a long-chain alkyl group-containing polymer and an organic polymer that is different from the long-chain alkyl group-containing polymer.

9 . The infrared-sensitive planographic printing plate precursor of claim 8 , wherein the recording layer has a multi-layered structure including a layer nearest to the support and a layer furthest from the support, and at least one of the layer nearest to the support and/or the layer furthest from the support contains the infrared absorber.

10 . The infrared-sensitive planographic printing plate precursor of claim 8 , wherein the long-chain alkyl group-containing polymer is a copolymer of at least a monomer having a long-chain alkyl group and a vinyl monomer having a carboxyl group.

11 . The infrared-sensitive planographic printing plate precursor of claim 8 , wherein a long-chain alkyl group contained in the long-chain alkyl group-containing polymer has 6 or more carbon atoms.

12 . The infrared-sensitive planographic printing plate precursor of claim 8 , wherein the organic polymer layer contains particles of the long-chain alkyl group-containing polymer, and projections are formed of the particles on a surface of the organic polymer layer.

13 . The infrared-sensitive planographic printing plate precursor of claim 12 , wherein an average particle diameter of the particles is 0.05 to 50 μm.

14 . The infrared-sensitive planographic printing plate precursor of claim 8 , wherein the organic polymer layer contains the long-chain alkyl group-containing polymer in an amount of 0.01 to 30% by mass based on the total solid matter of the organic polymer layer.

15 . An infrared-sensitive planographic printing plate precursor comprising:

a support;

a recording layer on one surface of the support, which recording layer contains a water-insoluble and alkali-soluble resin and an infrared absorber, and is capable of forming an image by infrared irradiation; and

an organic polymer layer on the other surface of the support,

wherein the precursor comprises a matte surface on at least one of a surface of the recording layer and/or a surface of the organic polymer layer.

16 . The infrared-sensitive planographic printing plate precursor of claim 15 , wherein the recording layer has a multi-layered structure.

17 . The infrared-sensitive planographic printing plate precursor of claim 15 , wherein the matte surface is a surface with fine projections.

18 . The infrared-sensitive planographic printing plate precursor of claim 17 , wherein an average diameter of the fine projections is 0.1 to 50 μm.

19 . The infrared-sensitive planographic printing plate precursor of claim 17 , wherein the fine projections contain a resin.

20 . The infrared-sensitive planographic printing plate precursor of claim 17 , wherein a density of the fine projections is 1 to 1000/mm 2 .